Loading...
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * n_gsm.c GSM 0710 tty multiplexor
4 * Copyright (c) 2009/10 Intel Corporation
5 *
6 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
7 *
8 * TO DO:
9 * Mostly done: ioctls for setting modes/timing
10 * Partly done: hooks so you can pull off frames to non tty devs
11 * Restart DLCI 0 when it closes ?
12 * Improve the tx engine
13 * Resolve tx side locking by adding a queue_head and routing
14 * all control traffic via it
15 * General tidy/document
16 * Review the locking/move to refcounts more (mux now moved to an
17 * alloc/free model ready)
18 * Use newest tty open/close port helpers and install hooks
19 * What to do about power functions ?
20 * Termios setting and negotiation
21 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
22 *
23 */
24
25#include <linux/types.h>
26#include <linux/major.h>
27#include <linux/errno.h>
28#include <linux/signal.h>
29#include <linux/fcntl.h>
30#include <linux/sched/signal.h>
31#include <linux/interrupt.h>
32#include <linux/tty.h>
33#include <linux/ctype.h>
34#include <linux/mm.h>
35#include <linux/string.h>
36#include <linux/slab.h>
37#include <linux/poll.h>
38#include <linux/bitops.h>
39#include <linux/file.h>
40#include <linux/uaccess.h>
41#include <linux/module.h>
42#include <linux/timer.h>
43#include <linux/tty_flip.h>
44#include <linux/tty_driver.h>
45#include <linux/serial.h>
46#include <linux/kfifo.h>
47#include <linux/skbuff.h>
48#include <net/arp.h>
49#include <linux/ip.h>
50#include <linux/netdevice.h>
51#include <linux/etherdevice.h>
52#include <linux/gsmmux.h>
53
54static int debug;
55module_param(debug, int, 0600);
56
57/* Defaults: these are from the specification */
58
59#define T1 10 /* 100mS */
60#define T2 34 /* 333mS */
61#define N2 3 /* Retry 3 times */
62
63/* Use long timers for testing at low speed with debug on */
64#ifdef DEBUG_TIMING
65#define T1 100
66#define T2 200
67#endif
68
69/*
70 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
71 * limits so this is plenty
72 */
73#define MAX_MRU 1500
74#define MAX_MTU 1500
75#define GSM_NET_TX_TIMEOUT (HZ*10)
76
77/**
78 * struct gsm_mux_net - network interface
79 * @struct gsm_dlci* dlci
80 *
81 * Created when net interface is initialized.
82 **/
83struct gsm_mux_net {
84 struct kref ref;
85 struct gsm_dlci *dlci;
86};
87
88/*
89 * Each block of data we have queued to go out is in the form of
90 * a gsm_msg which holds everything we need in a link layer independent
91 * format
92 */
93
94struct gsm_msg {
95 struct list_head list;
96 u8 addr; /* DLCI address + flags */
97 u8 ctrl; /* Control byte + flags */
98 unsigned int len; /* Length of data block (can be zero) */
99 unsigned char *data; /* Points into buffer but not at the start */
100 unsigned char buffer[0];
101};
102
103/*
104 * Each active data link has a gsm_dlci structure associated which ties
105 * the link layer to an optional tty (if the tty side is open). To avoid
106 * complexity right now these are only ever freed up when the mux is
107 * shut down.
108 *
109 * At the moment we don't free DLCI objects until the mux is torn down
110 * this avoid object life time issues but might be worth review later.
111 */
112
113struct gsm_dlci {
114 struct gsm_mux *gsm;
115 int addr;
116 int state;
117#define DLCI_CLOSED 0
118#define DLCI_OPENING 1 /* Sending SABM not seen UA */
119#define DLCI_OPEN 2 /* SABM/UA complete */
120#define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
121 struct mutex mutex;
122
123 /* Link layer */
124 int mode;
125#define DLCI_MODE_ABM 0 /* Normal Asynchronous Balanced Mode */
126#define DLCI_MODE_ADM 1 /* Asynchronous Disconnected Mode */
127 spinlock_t lock; /* Protects the internal state */
128 struct timer_list t1; /* Retransmit timer for SABM and UA */
129 int retries;
130 /* Uplink tty if active */
131 struct tty_port port; /* The tty bound to this DLCI if there is one */
132 struct kfifo *fifo; /* Queue fifo for the DLCI */
133 struct kfifo _fifo; /* For new fifo API porting only */
134 int adaption; /* Adaption layer in use */
135 int prev_adaption;
136 u32 modem_rx; /* Our incoming virtual modem lines */
137 u32 modem_tx; /* Our outgoing modem lines */
138 int dead; /* Refuse re-open */
139 /* Flow control */
140 int throttled; /* Private copy of throttle state */
141 int constipated; /* Throttle status for outgoing */
142 /* Packetised I/O */
143 struct sk_buff *skb; /* Frame being sent */
144 struct sk_buff_head skb_list; /* Queued frames */
145 /* Data handling callback */
146 void (*data)(struct gsm_dlci *dlci, const u8 *data, int len);
147 void (*prev_data)(struct gsm_dlci *dlci, const u8 *data, int len);
148 struct net_device *net; /* network interface, if created */
149};
150
151/* DLCI 0, 62/63 are special or reserved see gsmtty_open */
152
153#define NUM_DLCI 64
154
155/*
156 * DLCI 0 is used to pass control blocks out of band of the data
157 * flow (and with a higher link priority). One command can be outstanding
158 * at a time and we use this structure to manage them. They are created
159 * and destroyed by the user context, and updated by the receive paths
160 * and timers
161 */
162
163struct gsm_control {
164 u8 cmd; /* Command we are issuing */
165 u8 *data; /* Data for the command in case we retransmit */
166 int len; /* Length of block for retransmission */
167 int done; /* Done flag */
168 int error; /* Error if any */
169};
170
171/*
172 * Each GSM mux we have is represented by this structure. If we are
173 * operating as an ldisc then we use this structure as our ldisc
174 * state. We need to sort out lifetimes and locking with respect
175 * to the gsm mux array. For now we don't free DLCI objects that
176 * have been instantiated until the mux itself is terminated.
177 *
178 * To consider further: tty open versus mux shutdown.
179 */
180
181struct gsm_mux {
182 struct tty_struct *tty; /* The tty our ldisc is bound to */
183 spinlock_t lock;
184 struct mutex mutex;
185 unsigned int num;
186 struct kref ref;
187
188 /* Events on the GSM channel */
189 wait_queue_head_t event;
190
191 /* Bits for GSM mode decoding */
192
193 /* Framing Layer */
194 unsigned char *buf;
195 int state;
196#define GSM_SEARCH 0
197#define GSM_START 1
198#define GSM_ADDRESS 2
199#define GSM_CONTROL 3
200#define GSM_LEN 4
201#define GSM_DATA 5
202#define GSM_FCS 6
203#define GSM_OVERRUN 7
204#define GSM_LEN0 8
205#define GSM_LEN1 9
206#define GSM_SSOF 10
207 unsigned int len;
208 unsigned int address;
209 unsigned int count;
210 int escape;
211 int encoding;
212 u8 control;
213 u8 fcs;
214 u8 received_fcs;
215 u8 *txframe; /* TX framing buffer */
216
217 /* Methods for the receiver side */
218 void (*receive)(struct gsm_mux *gsm, u8 ch);
219 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
220 /* And transmit side */
221 int (*output)(struct gsm_mux *mux, u8 *data, int len);
222
223 /* Link Layer */
224 unsigned int mru;
225 unsigned int mtu;
226 int initiator; /* Did we initiate connection */
227 int dead; /* Has the mux been shut down */
228 struct gsm_dlci *dlci[NUM_DLCI];
229 int constipated; /* Asked by remote to shut up */
230
231 spinlock_t tx_lock;
232 unsigned int tx_bytes; /* TX data outstanding */
233#define TX_THRESH_HI 8192
234#define TX_THRESH_LO 2048
235 struct list_head tx_list; /* Pending data packets */
236
237 /* Control messages */
238 struct timer_list t2_timer; /* Retransmit timer for commands */
239 int cretries; /* Command retry counter */
240 struct gsm_control *pending_cmd;/* Our current pending command */
241 spinlock_t control_lock; /* Protects the pending command */
242
243 /* Configuration */
244 int adaption; /* 1 or 2 supported */
245 u8 ftype; /* UI or UIH */
246 int t1, t2; /* Timers in 1/100th of a sec */
247 int n2; /* Retry count */
248
249 /* Statistics (not currently exposed) */
250 unsigned long bad_fcs;
251 unsigned long malformed;
252 unsigned long io_error;
253 unsigned long bad_size;
254 unsigned long unsupported;
255};
256
257
258/*
259 * Mux objects - needed so that we can translate a tty index into the
260 * relevant mux and DLCI.
261 */
262
263#define MAX_MUX 4 /* 256 minors */
264static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
265static spinlock_t gsm_mux_lock;
266
267static struct tty_driver *gsm_tty_driver;
268
269/*
270 * This section of the driver logic implements the GSM encodings
271 * both the basic and the 'advanced'. Reliable transport is not
272 * supported.
273 */
274
275#define CR 0x02
276#define EA 0x01
277#define PF 0x10
278
279/* I is special: the rest are ..*/
280#define RR 0x01
281#define UI 0x03
282#define RNR 0x05
283#define REJ 0x09
284#define DM 0x0F
285#define SABM 0x2F
286#define DISC 0x43
287#define UA 0x63
288#define UIH 0xEF
289
290/* Channel commands */
291#define CMD_NSC 0x09
292#define CMD_TEST 0x11
293#define CMD_PSC 0x21
294#define CMD_RLS 0x29
295#define CMD_FCOFF 0x31
296#define CMD_PN 0x41
297#define CMD_RPN 0x49
298#define CMD_FCON 0x51
299#define CMD_CLD 0x61
300#define CMD_SNC 0x69
301#define CMD_MSC 0x71
302
303/* Virtual modem bits */
304#define MDM_FC 0x01
305#define MDM_RTC 0x02
306#define MDM_RTR 0x04
307#define MDM_IC 0x20
308#define MDM_DV 0x40
309
310#define GSM0_SOF 0xF9
311#define GSM1_SOF 0x7E
312#define GSM1_ESCAPE 0x7D
313#define GSM1_ESCAPE_BITS 0x20
314#define XON 0x11
315#define XOFF 0x13
316
317static const struct tty_port_operations gsm_port_ops;
318
319/*
320 * CRC table for GSM 0710
321 */
322
323static const u8 gsm_fcs8[256] = {
324 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
325 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
326 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
327 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
328 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
329 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
330 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
331 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
332 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
333 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
334 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
335 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
336 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
337 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
338 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
339 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
340 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
341 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
342 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
343 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
344 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
345 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
346 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
347 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
348 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
349 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
350 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
351 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
352 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
353 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
354 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
355 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
356};
357
358#define INIT_FCS 0xFF
359#define GOOD_FCS 0xCF
360
361/**
362 * gsm_fcs_add - update FCS
363 * @fcs: Current FCS
364 * @c: Next data
365 *
366 * Update the FCS to include c. Uses the algorithm in the specification
367 * notes.
368 */
369
370static inline u8 gsm_fcs_add(u8 fcs, u8 c)
371{
372 return gsm_fcs8[fcs ^ c];
373}
374
375/**
376 * gsm_fcs_add_block - update FCS for a block
377 * @fcs: Current FCS
378 * @c: buffer of data
379 * @len: length of buffer
380 *
381 * Update the FCS to include c. Uses the algorithm in the specification
382 * notes.
383 */
384
385static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
386{
387 while (len--)
388 fcs = gsm_fcs8[fcs ^ *c++];
389 return fcs;
390}
391
392/**
393 * gsm_read_ea - read a byte into an EA
394 * @val: variable holding value
395 * c: byte going into the EA
396 *
397 * Processes one byte of an EA. Updates the passed variable
398 * and returns 1 if the EA is now completely read
399 */
400
401static int gsm_read_ea(unsigned int *val, u8 c)
402{
403 /* Add the next 7 bits into the value */
404 *val <<= 7;
405 *val |= c >> 1;
406 /* Was this the last byte of the EA 1 = yes*/
407 return c & EA;
408}
409
410/**
411 * gsm_encode_modem - encode modem data bits
412 * @dlci: DLCI to encode from
413 *
414 * Returns the correct GSM encoded modem status bits (6 bit field) for
415 * the current status of the DLCI and attached tty object
416 */
417
418static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
419{
420 u8 modembits = 0;
421 /* FC is true flow control not modem bits */
422 if (dlci->throttled)
423 modembits |= MDM_FC;
424 if (dlci->modem_tx & TIOCM_DTR)
425 modembits |= MDM_RTC;
426 if (dlci->modem_tx & TIOCM_RTS)
427 modembits |= MDM_RTR;
428 if (dlci->modem_tx & TIOCM_RI)
429 modembits |= MDM_IC;
430 if (dlci->modem_tx & TIOCM_CD)
431 modembits |= MDM_DV;
432 return modembits;
433}
434
435/**
436 * gsm_print_packet - display a frame for debug
437 * @hdr: header to print before decode
438 * @addr: address EA from the frame
439 * @cr: C/R bit from the frame
440 * @control: control including PF bit
441 * @data: following data bytes
442 * @dlen: length of data
443 *
444 * Displays a packet in human readable format for debugging purposes. The
445 * style is based on amateur radio LAP-B dump display.
446 */
447
448static void gsm_print_packet(const char *hdr, int addr, int cr,
449 u8 control, const u8 *data, int dlen)
450{
451 if (!(debug & 1))
452 return;
453
454 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
455
456 switch (control & ~PF) {
457 case SABM:
458 pr_cont("SABM");
459 break;
460 case UA:
461 pr_cont("UA");
462 break;
463 case DISC:
464 pr_cont("DISC");
465 break;
466 case DM:
467 pr_cont("DM");
468 break;
469 case UI:
470 pr_cont("UI");
471 break;
472 case UIH:
473 pr_cont("UIH");
474 break;
475 default:
476 if (!(control & 0x01)) {
477 pr_cont("I N(S)%d N(R)%d",
478 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
479 } else switch (control & 0x0F) {
480 case RR:
481 pr_cont("RR(%d)", (control & 0xE0) >> 5);
482 break;
483 case RNR:
484 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
485 break;
486 case REJ:
487 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
488 break;
489 default:
490 pr_cont("[%02X]", control);
491 }
492 }
493
494 if (control & PF)
495 pr_cont("(P)");
496 else
497 pr_cont("(F)");
498
499 if (dlen) {
500 int ct = 0;
501 while (dlen--) {
502 if (ct % 8 == 0) {
503 pr_cont("\n");
504 pr_debug(" ");
505 }
506 pr_cont("%02X ", *data++);
507 ct++;
508 }
509 }
510 pr_cont("\n");
511}
512
513
514/*
515 * Link level transmission side
516 */
517
518/**
519 * gsm_stuff_packet - bytestuff a packet
520 * @ibuf: input
521 * @obuf: output
522 * @len: length of input
523 *
524 * Expand a buffer by bytestuffing it. The worst case size change
525 * is doubling and the caller is responsible for handing out
526 * suitable sized buffers.
527 */
528
529static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
530{
531 int olen = 0;
532 while (len--) {
533 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
534 || *input == XON || *input == XOFF) {
535 *output++ = GSM1_ESCAPE;
536 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
537 olen++;
538 } else
539 *output++ = *input++;
540 olen++;
541 }
542 return olen;
543}
544
545/**
546 * gsm_send - send a control frame
547 * @gsm: our GSM mux
548 * @addr: address for control frame
549 * @cr: command/response bit
550 * @control: control byte including PF bit
551 *
552 * Format up and transmit a control frame. These do not go via the
553 * queueing logic as they should be transmitted ahead of data when
554 * they are needed.
555 *
556 * FIXME: Lock versus data TX path
557 */
558
559static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
560{
561 int len;
562 u8 cbuf[10];
563 u8 ibuf[3];
564
565 switch (gsm->encoding) {
566 case 0:
567 cbuf[0] = GSM0_SOF;
568 cbuf[1] = (addr << 2) | (cr << 1) | EA;
569 cbuf[2] = control;
570 cbuf[3] = EA; /* Length of data = 0 */
571 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
572 cbuf[5] = GSM0_SOF;
573 len = 6;
574 break;
575 case 1:
576 case 2:
577 /* Control frame + packing (but not frame stuffing) in mode 1 */
578 ibuf[0] = (addr << 2) | (cr << 1) | EA;
579 ibuf[1] = control;
580 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
581 /* Stuffing may double the size worst case */
582 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
583 /* Now add the SOF markers */
584 cbuf[0] = GSM1_SOF;
585 cbuf[len + 1] = GSM1_SOF;
586 /* FIXME: we can omit the lead one in many cases */
587 len += 2;
588 break;
589 default:
590 WARN_ON(1);
591 return;
592 }
593 gsm->output(gsm, cbuf, len);
594 gsm_print_packet("-->", addr, cr, control, NULL, 0);
595}
596
597/**
598 * gsm_response - send a control response
599 * @gsm: our GSM mux
600 * @addr: address for control frame
601 * @control: control byte including PF bit
602 *
603 * Format up and transmit a link level response frame.
604 */
605
606static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
607{
608 gsm_send(gsm, addr, 0, control);
609}
610
611/**
612 * gsm_command - send a control command
613 * @gsm: our GSM mux
614 * @addr: address for control frame
615 * @control: control byte including PF bit
616 *
617 * Format up and transmit a link level command frame.
618 */
619
620static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
621{
622 gsm_send(gsm, addr, 1, control);
623}
624
625/* Data transmission */
626
627#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
628
629/**
630 * gsm_data_alloc - allocate data frame
631 * @gsm: GSM mux
632 * @addr: DLCI address
633 * @len: length excluding header and FCS
634 * @ctrl: control byte
635 *
636 * Allocate a new data buffer for sending frames with data. Space is left
637 * at the front for header bytes but that is treated as an implementation
638 * detail and not for the high level code to use
639 */
640
641static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
642 u8 ctrl)
643{
644 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
645 GFP_ATOMIC);
646 if (m == NULL)
647 return NULL;
648 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
649 m->len = len;
650 m->addr = addr;
651 m->ctrl = ctrl;
652 INIT_LIST_HEAD(&m->list);
653 return m;
654}
655
656/**
657 * gsm_data_kick - poke the queue
658 * @gsm: GSM Mux
659 *
660 * The tty device has called us to indicate that room has appeared in
661 * the transmit queue. Ram more data into the pipe if we have any
662 * If we have been flow-stopped by a CMD_FCOFF, then we can only
663 * send messages on DLCI0 until CMD_FCON
664 *
665 * FIXME: lock against link layer control transmissions
666 */
667
668static void gsm_data_kick(struct gsm_mux *gsm)
669{
670 struct gsm_msg *msg, *nmsg;
671 int len;
672 int skip_sof = 0;
673
674 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
675 if (gsm->constipated && msg->addr)
676 continue;
677 if (gsm->encoding != 0) {
678 gsm->txframe[0] = GSM1_SOF;
679 len = gsm_stuff_frame(msg->data,
680 gsm->txframe + 1, msg->len);
681 gsm->txframe[len + 1] = GSM1_SOF;
682 len += 2;
683 } else {
684 gsm->txframe[0] = GSM0_SOF;
685 memcpy(gsm->txframe + 1 , msg->data, msg->len);
686 gsm->txframe[msg->len + 1] = GSM0_SOF;
687 len = msg->len + 2;
688 }
689
690 if (debug & 4)
691 print_hex_dump_bytes("gsm_data_kick: ",
692 DUMP_PREFIX_OFFSET,
693 gsm->txframe, len);
694
695 if (gsm->output(gsm, gsm->txframe + skip_sof,
696 len - skip_sof) < 0)
697 break;
698 /* FIXME: Can eliminate one SOF in many more cases */
699 gsm->tx_bytes -= msg->len;
700 /* For a burst of frames skip the extra SOF within the
701 burst */
702 skip_sof = 1;
703
704 list_del(&msg->list);
705 kfree(msg);
706 }
707}
708
709/**
710 * __gsm_data_queue - queue a UI or UIH frame
711 * @dlci: DLCI sending the data
712 * @msg: message queued
713 *
714 * Add data to the transmit queue and try and get stuff moving
715 * out of the mux tty if not already doing so. The Caller must hold
716 * the gsm tx lock.
717 */
718
719static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
720{
721 struct gsm_mux *gsm = dlci->gsm;
722 u8 *dp = msg->data;
723 u8 *fcs = dp + msg->len;
724
725 /* Fill in the header */
726 if (gsm->encoding == 0) {
727 if (msg->len < 128)
728 *--dp = (msg->len << 1) | EA;
729 else {
730 *--dp = (msg->len >> 7); /* bits 7 - 15 */
731 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
732 }
733 }
734
735 *--dp = msg->ctrl;
736 if (gsm->initiator)
737 *--dp = (msg->addr << 2) | 2 | EA;
738 else
739 *--dp = (msg->addr << 2) | EA;
740 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
741 /* Ugly protocol layering violation */
742 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
743 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
744 *fcs = 0xFF - *fcs;
745
746 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
747 msg->data, msg->len);
748
749 /* Move the header back and adjust the length, also allow for the FCS
750 now tacked on the end */
751 msg->len += (msg->data - dp) + 1;
752 msg->data = dp;
753
754 /* Add to the actual output queue */
755 list_add_tail(&msg->list, &gsm->tx_list);
756 gsm->tx_bytes += msg->len;
757 gsm_data_kick(gsm);
758}
759
760/**
761 * gsm_data_queue - queue a UI or UIH frame
762 * @dlci: DLCI sending the data
763 * @msg: message queued
764 *
765 * Add data to the transmit queue and try and get stuff moving
766 * out of the mux tty if not already doing so. Take the
767 * the gsm tx lock and dlci lock.
768 */
769
770static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
771{
772 unsigned long flags;
773 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
774 __gsm_data_queue(dlci, msg);
775 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
776}
777
778/**
779 * gsm_dlci_data_output - try and push data out of a DLCI
780 * @gsm: mux
781 * @dlci: the DLCI to pull data from
782 *
783 * Pull data from a DLCI and send it into the transmit queue if there
784 * is data. Keep to the MRU of the mux. This path handles the usual tty
785 * interface which is a byte stream with optional modem data.
786 *
787 * Caller must hold the tx_lock of the mux.
788 */
789
790static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
791{
792 struct gsm_msg *msg;
793 u8 *dp;
794 int len, total_size, size;
795 int h = dlci->adaption - 1;
796
797 total_size = 0;
798 while (1) {
799 len = kfifo_len(dlci->fifo);
800 if (len == 0)
801 return total_size;
802
803 /* MTU/MRU count only the data bits */
804 if (len > gsm->mtu)
805 len = gsm->mtu;
806
807 size = len + h;
808
809 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
810 /* FIXME: need a timer or something to kick this so it can't
811 get stuck with no work outstanding and no buffer free */
812 if (msg == NULL)
813 return -ENOMEM;
814 dp = msg->data;
815 switch (dlci->adaption) {
816 case 1: /* Unstructured */
817 break;
818 case 2: /* Unstructed with modem bits.
819 Always one byte as we never send inline break data */
820 *dp++ = gsm_encode_modem(dlci);
821 break;
822 }
823 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
824 __gsm_data_queue(dlci, msg);
825 total_size += size;
826 }
827 /* Bytes of data we used up */
828 return total_size;
829}
830
831/**
832 * gsm_dlci_data_output_framed - try and push data out of a DLCI
833 * @gsm: mux
834 * @dlci: the DLCI to pull data from
835 *
836 * Pull data from a DLCI and send it into the transmit queue if there
837 * is data. Keep to the MRU of the mux. This path handles framed data
838 * queued as skbuffs to the DLCI.
839 *
840 * Caller must hold the tx_lock of the mux.
841 */
842
843static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
844 struct gsm_dlci *dlci)
845{
846 struct gsm_msg *msg;
847 u8 *dp;
848 int len, size;
849 int last = 0, first = 0;
850 int overhead = 0;
851
852 /* One byte per frame is used for B/F flags */
853 if (dlci->adaption == 4)
854 overhead = 1;
855
856 /* dlci->skb is locked by tx_lock */
857 if (dlci->skb == NULL) {
858 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
859 if (dlci->skb == NULL)
860 return 0;
861 first = 1;
862 }
863 len = dlci->skb->len + overhead;
864
865 /* MTU/MRU count only the data bits */
866 if (len > gsm->mtu) {
867 if (dlci->adaption == 3) {
868 /* Over long frame, bin it */
869 dev_kfree_skb_any(dlci->skb);
870 dlci->skb = NULL;
871 return 0;
872 }
873 len = gsm->mtu;
874 } else
875 last = 1;
876
877 size = len + overhead;
878 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
879
880 /* FIXME: need a timer or something to kick this so it can't
881 get stuck with no work outstanding and no buffer free */
882 if (msg == NULL) {
883 skb_queue_tail(&dlci->skb_list, dlci->skb);
884 dlci->skb = NULL;
885 return -ENOMEM;
886 }
887 dp = msg->data;
888
889 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
890 /* Flag byte to carry the start/end info */
891 *dp++ = last << 7 | first << 6 | 1; /* EA */
892 len--;
893 }
894 memcpy(dp, dlci->skb->data, len);
895 skb_pull(dlci->skb, len);
896 __gsm_data_queue(dlci, msg);
897 if (last) {
898 dev_kfree_skb_any(dlci->skb);
899 dlci->skb = NULL;
900 }
901 return size;
902}
903
904/**
905 * gsm_dlci_data_sweep - look for data to send
906 * @gsm: the GSM mux
907 *
908 * Sweep the GSM mux channels in priority order looking for ones with
909 * data to send. We could do with optimising this scan a bit. We aim
910 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
911 * TX_THRESH_LO we get called again
912 *
913 * FIXME: We should round robin between groups and in theory you can
914 * renegotiate DLCI priorities with optional stuff. Needs optimising.
915 */
916
917static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
918{
919 int len;
920 /* Priority ordering: We should do priority with RR of the groups */
921 int i = 1;
922
923 while (i < NUM_DLCI) {
924 struct gsm_dlci *dlci;
925
926 if (gsm->tx_bytes > TX_THRESH_HI)
927 break;
928 dlci = gsm->dlci[i];
929 if (dlci == NULL || dlci->constipated) {
930 i++;
931 continue;
932 }
933 if (dlci->adaption < 3 && !dlci->net)
934 len = gsm_dlci_data_output(gsm, dlci);
935 else
936 len = gsm_dlci_data_output_framed(gsm, dlci);
937 if (len < 0)
938 break;
939 /* DLCI empty - try the next */
940 if (len == 0)
941 i++;
942 }
943}
944
945/**
946 * gsm_dlci_data_kick - transmit if possible
947 * @dlci: DLCI to kick
948 *
949 * Transmit data from this DLCI if the queue is empty. We can't rely on
950 * a tty wakeup except when we filled the pipe so we need to fire off
951 * new data ourselves in other cases.
952 */
953
954static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
955{
956 unsigned long flags;
957 int sweep;
958
959 if (dlci->constipated)
960 return;
961
962 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
963 /* If we have nothing running then we need to fire up */
964 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
965 if (dlci->gsm->tx_bytes == 0) {
966 if (dlci->net)
967 gsm_dlci_data_output_framed(dlci->gsm, dlci);
968 else
969 gsm_dlci_data_output(dlci->gsm, dlci);
970 }
971 if (sweep)
972 gsm_dlci_data_sweep(dlci->gsm);
973 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
974}
975
976/*
977 * Control message processing
978 */
979
980
981/**
982 * gsm_control_reply - send a response frame to a control
983 * @gsm: gsm channel
984 * @cmd: the command to use
985 * @data: data to follow encoded info
986 * @dlen: length of data
987 *
988 * Encode up and queue a UI/UIH frame containing our response.
989 */
990
991static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data,
992 int dlen)
993{
994 struct gsm_msg *msg;
995 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
996 if (msg == NULL)
997 return;
998 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
999 msg->data[1] = (dlen << 1) | EA;
1000 memcpy(msg->data + 2, data, dlen);
1001 gsm_data_queue(gsm->dlci[0], msg);
1002}
1003
1004/**
1005 * gsm_process_modem - process received modem status
1006 * @tty: virtual tty bound to the DLCI
1007 * @dlci: DLCI to affect
1008 * @modem: modem bits (full EA)
1009 *
1010 * Used when a modem control message or line state inline in adaption
1011 * layer 2 is processed. Sort out the local modem state and throttles
1012 */
1013
1014static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1015 u32 modem, int clen)
1016{
1017 int mlines = 0;
1018 u8 brk = 0;
1019 int fc;
1020
1021 /* The modem status command can either contain one octet (v.24 signals)
1022 or two octets (v.24 signals + break signals). The length field will
1023 either be 2 or 3 respectively. This is specified in section
1024 5.4.6.3.7 of the 27.010 mux spec. */
1025
1026 if (clen == 2)
1027 modem = modem & 0x7f;
1028 else {
1029 brk = modem & 0x7f;
1030 modem = (modem >> 7) & 0x7f;
1031 }
1032
1033 /* Flow control/ready to communicate */
1034 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1035 if (fc && !dlci->constipated) {
1036 /* Need to throttle our output on this device */
1037 dlci->constipated = 1;
1038 } else if (!fc && dlci->constipated) {
1039 dlci->constipated = 0;
1040 gsm_dlci_data_kick(dlci);
1041 }
1042
1043 /* Map modem bits */
1044 if (modem & MDM_RTC)
1045 mlines |= TIOCM_DSR | TIOCM_DTR;
1046 if (modem & MDM_RTR)
1047 mlines |= TIOCM_RTS | TIOCM_CTS;
1048 if (modem & MDM_IC)
1049 mlines |= TIOCM_RI;
1050 if (modem & MDM_DV)
1051 mlines |= TIOCM_CD;
1052
1053 /* Carrier drop -> hangup */
1054 if (tty) {
1055 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1056 if (!C_CLOCAL(tty))
1057 tty_hangup(tty);
1058 }
1059 if (brk & 0x01)
1060 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1061 dlci->modem_rx = mlines;
1062}
1063
1064/**
1065 * gsm_control_modem - modem status received
1066 * @gsm: GSM channel
1067 * @data: data following command
1068 * @clen: command length
1069 *
1070 * We have received a modem status control message. This is used by
1071 * the GSM mux protocol to pass virtual modem line status and optionally
1072 * to indicate break signals. Unpack it, convert to Linux representation
1073 * and if need be stuff a break message down the tty.
1074 */
1075
1076static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
1077{
1078 unsigned int addr = 0;
1079 unsigned int modem = 0;
1080 unsigned int brk = 0;
1081 struct gsm_dlci *dlci;
1082 int len = clen;
1083 const u8 *dp = data;
1084 struct tty_struct *tty;
1085
1086 while (gsm_read_ea(&addr, *dp++) == 0) {
1087 len--;
1088 if (len == 0)
1089 return;
1090 }
1091 /* Must be at least one byte following the EA */
1092 len--;
1093 if (len <= 0)
1094 return;
1095
1096 addr >>= 1;
1097 /* Closed port, or invalid ? */
1098 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1099 return;
1100 dlci = gsm->dlci[addr];
1101
1102 while (gsm_read_ea(&modem, *dp++) == 0) {
1103 len--;
1104 if (len == 0)
1105 return;
1106 }
1107 len--;
1108 if (len > 0) {
1109 while (gsm_read_ea(&brk, *dp++) == 0) {
1110 len--;
1111 if (len == 0)
1112 return;
1113 }
1114 modem <<= 7;
1115 modem |= (brk & 0x7f);
1116 }
1117 tty = tty_port_tty_get(&dlci->port);
1118 gsm_process_modem(tty, dlci, modem, clen);
1119 if (tty) {
1120 tty_wakeup(tty);
1121 tty_kref_put(tty);
1122 }
1123 gsm_control_reply(gsm, CMD_MSC, data, clen);
1124}
1125
1126/**
1127 * gsm_control_rls - remote line status
1128 * @gsm: GSM channel
1129 * @data: data bytes
1130 * @clen: data length
1131 *
1132 * The modem sends us a two byte message on the control channel whenever
1133 * it wishes to send us an error state from the virtual link. Stuff
1134 * this into the uplink tty if present
1135 */
1136
1137static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen)
1138{
1139 struct tty_port *port;
1140 unsigned int addr = 0;
1141 u8 bits;
1142 int len = clen;
1143 const u8 *dp = data;
1144
1145 while (gsm_read_ea(&addr, *dp++) == 0) {
1146 len--;
1147 if (len == 0)
1148 return;
1149 }
1150 /* Must be at least one byte following ea */
1151 len--;
1152 if (len <= 0)
1153 return;
1154 addr >>= 1;
1155 /* Closed port, or invalid ? */
1156 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1157 return;
1158 /* No error ? */
1159 bits = *dp;
1160 if ((bits & 1) == 0)
1161 return;
1162
1163 port = &gsm->dlci[addr]->port;
1164
1165 if (bits & 2)
1166 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1167 if (bits & 4)
1168 tty_insert_flip_char(port, 0, TTY_PARITY);
1169 if (bits & 8)
1170 tty_insert_flip_char(port, 0, TTY_FRAME);
1171
1172 tty_flip_buffer_push(port);
1173
1174 gsm_control_reply(gsm, CMD_RLS, data, clen);
1175}
1176
1177static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1178
1179/**
1180 * gsm_control_message - DLCI 0 control processing
1181 * @gsm: our GSM mux
1182 * @command: the command EA
1183 * @data: data beyond the command/length EAs
1184 * @clen: length
1185 *
1186 * Input processor for control messages from the other end of the link.
1187 * Processes the incoming request and queues a response frame or an
1188 * NSC response if not supported
1189 */
1190
1191static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1192 const u8 *data, int clen)
1193{
1194 u8 buf[1];
1195 unsigned long flags;
1196
1197 switch (command) {
1198 case CMD_CLD: {
1199 struct gsm_dlci *dlci = gsm->dlci[0];
1200 /* Modem wishes to close down */
1201 if (dlci) {
1202 dlci->dead = 1;
1203 gsm->dead = 1;
1204 gsm_dlci_begin_close(dlci);
1205 }
1206 }
1207 break;
1208 case CMD_TEST:
1209 /* Modem wishes to test, reply with the data */
1210 gsm_control_reply(gsm, CMD_TEST, data, clen);
1211 break;
1212 case CMD_FCON:
1213 /* Modem can accept data again */
1214 gsm->constipated = 0;
1215 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1216 /* Kick the link in case it is idling */
1217 spin_lock_irqsave(&gsm->tx_lock, flags);
1218 gsm_data_kick(gsm);
1219 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1220 break;
1221 case CMD_FCOFF:
1222 /* Modem wants us to STFU */
1223 gsm->constipated = 1;
1224 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1225 break;
1226 case CMD_MSC:
1227 /* Out of band modem line change indicator for a DLCI */
1228 gsm_control_modem(gsm, data, clen);
1229 break;
1230 case CMD_RLS:
1231 /* Out of band error reception for a DLCI */
1232 gsm_control_rls(gsm, data, clen);
1233 break;
1234 case CMD_PSC:
1235 /* Modem wishes to enter power saving state */
1236 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1237 break;
1238 /* Optional unsupported commands */
1239 case CMD_PN: /* Parameter negotiation */
1240 case CMD_RPN: /* Remote port negotiation */
1241 case CMD_SNC: /* Service negotiation command */
1242 default:
1243 /* Reply to bad commands with an NSC */
1244 buf[0] = command;
1245 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1246 break;
1247 }
1248}
1249
1250/**
1251 * gsm_control_response - process a response to our control
1252 * @gsm: our GSM mux
1253 * @command: the command (response) EA
1254 * @data: data beyond the command/length EA
1255 * @clen: length
1256 *
1257 * Process a response to an outstanding command. We only allow a single
1258 * control message in flight so this is fairly easy. All the clean up
1259 * is done by the caller, we just update the fields, flag it as done
1260 * and return
1261 */
1262
1263static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1264 const u8 *data, int clen)
1265{
1266 struct gsm_control *ctrl;
1267 unsigned long flags;
1268
1269 spin_lock_irqsave(&gsm->control_lock, flags);
1270
1271 ctrl = gsm->pending_cmd;
1272 /* Does the reply match our command */
1273 command |= 1;
1274 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1275 /* Our command was replied to, kill the retry timer */
1276 del_timer(&gsm->t2_timer);
1277 gsm->pending_cmd = NULL;
1278 /* Rejected by the other end */
1279 if (command == CMD_NSC)
1280 ctrl->error = -EOPNOTSUPP;
1281 ctrl->done = 1;
1282 wake_up(&gsm->event);
1283 }
1284 spin_unlock_irqrestore(&gsm->control_lock, flags);
1285}
1286
1287/**
1288 * gsm_control_transmit - send control packet
1289 * @gsm: gsm mux
1290 * @ctrl: frame to send
1291 *
1292 * Send out a pending control command (called under control lock)
1293 */
1294
1295static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1296{
1297 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1298 if (msg == NULL)
1299 return;
1300 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1301 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1302 gsm_data_queue(gsm->dlci[0], msg);
1303}
1304
1305/**
1306 * gsm_control_retransmit - retransmit a control frame
1307 * @data: pointer to our gsm object
1308 *
1309 * Called off the T2 timer expiry in order to retransmit control frames
1310 * that have been lost in the system somewhere. The control_lock protects
1311 * us from colliding with another sender or a receive completion event.
1312 * In that situation the timer may still occur in a small window but
1313 * gsm->pending_cmd will be NULL and we just let the timer expire.
1314 */
1315
1316static void gsm_control_retransmit(struct timer_list *t)
1317{
1318 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer);
1319 struct gsm_control *ctrl;
1320 unsigned long flags;
1321 spin_lock_irqsave(&gsm->control_lock, flags);
1322 ctrl = gsm->pending_cmd;
1323 if (ctrl) {
1324 gsm->cretries--;
1325 if (gsm->cretries == 0) {
1326 gsm->pending_cmd = NULL;
1327 ctrl->error = -ETIMEDOUT;
1328 ctrl->done = 1;
1329 spin_unlock_irqrestore(&gsm->control_lock, flags);
1330 wake_up(&gsm->event);
1331 return;
1332 }
1333 gsm_control_transmit(gsm, ctrl);
1334 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1335 }
1336 spin_unlock_irqrestore(&gsm->control_lock, flags);
1337}
1338
1339/**
1340 * gsm_control_send - send a control frame on DLCI 0
1341 * @gsm: the GSM channel
1342 * @command: command to send including CR bit
1343 * @data: bytes of data (must be kmalloced)
1344 * @len: length of the block to send
1345 *
1346 * Queue and dispatch a control command. Only one command can be
1347 * active at a time. In theory more can be outstanding but the matching
1348 * gets really complicated so for now stick to one outstanding.
1349 */
1350
1351static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1352 unsigned int command, u8 *data, int clen)
1353{
1354 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1355 GFP_KERNEL);
1356 unsigned long flags;
1357 if (ctrl == NULL)
1358 return NULL;
1359retry:
1360 wait_event(gsm->event, gsm->pending_cmd == NULL);
1361 spin_lock_irqsave(&gsm->control_lock, flags);
1362 if (gsm->pending_cmd != NULL) {
1363 spin_unlock_irqrestore(&gsm->control_lock, flags);
1364 goto retry;
1365 }
1366 ctrl->cmd = command;
1367 ctrl->data = data;
1368 ctrl->len = clen;
1369 gsm->pending_cmd = ctrl;
1370
1371 /* If DLCI0 is in ADM mode skip retries, it won't respond */
1372 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
1373 gsm->cretries = 1;
1374 else
1375 gsm->cretries = gsm->n2;
1376
1377 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1378 gsm_control_transmit(gsm, ctrl);
1379 spin_unlock_irqrestore(&gsm->control_lock, flags);
1380 return ctrl;
1381}
1382
1383/**
1384 * gsm_control_wait - wait for a control to finish
1385 * @gsm: GSM mux
1386 * @control: control we are waiting on
1387 *
1388 * Waits for the control to complete or time out. Frees any used
1389 * resources and returns 0 for success, or an error if the remote
1390 * rejected or ignored the request.
1391 */
1392
1393static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1394{
1395 int err;
1396 wait_event(gsm->event, control->done == 1);
1397 err = control->error;
1398 kfree(control);
1399 return err;
1400}
1401
1402
1403/*
1404 * DLCI level handling: Needs krefs
1405 */
1406
1407/*
1408 * State transitions and timers
1409 */
1410
1411/**
1412 * gsm_dlci_close - a DLCI has closed
1413 * @dlci: DLCI that closed
1414 *
1415 * Perform processing when moving a DLCI into closed state. If there
1416 * is an attached tty this is hung up
1417 */
1418
1419static void gsm_dlci_close(struct gsm_dlci *dlci)
1420{
1421 del_timer(&dlci->t1);
1422 if (debug & 8)
1423 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1424 dlci->state = DLCI_CLOSED;
1425 if (dlci->addr != 0) {
1426 tty_port_tty_hangup(&dlci->port, false);
1427 kfifo_reset(dlci->fifo);
1428 } else
1429 dlci->gsm->dead = 1;
1430 wake_up(&dlci->gsm->event);
1431 /* A DLCI 0 close is a MUX termination so we need to kick that
1432 back to userspace somehow */
1433}
1434
1435/**
1436 * gsm_dlci_open - a DLCI has opened
1437 * @dlci: DLCI that opened
1438 *
1439 * Perform processing when moving a DLCI into open state.
1440 */
1441
1442static void gsm_dlci_open(struct gsm_dlci *dlci)
1443{
1444 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1445 open -> open */
1446 del_timer(&dlci->t1);
1447 /* This will let a tty open continue */
1448 dlci->state = DLCI_OPEN;
1449 if (debug & 8)
1450 pr_debug("DLCI %d goes open.\n", dlci->addr);
1451 wake_up(&dlci->gsm->event);
1452}
1453
1454/**
1455 * gsm_dlci_t1 - T1 timer expiry
1456 * @dlci: DLCI that opened
1457 *
1458 * The T1 timer handles retransmits of control frames (essentially of
1459 * SABM and DISC). We resend the command until the retry count runs out
1460 * in which case an opening port goes back to closed and a closing port
1461 * is simply put into closed state (any further frames from the other
1462 * end will get a DM response)
1463 *
1464 * Some control dlci can stay in ADM mode with other dlci working just
1465 * fine. In that case we can just keep the control dlci open after the
1466 * DLCI_OPENING retries time out.
1467 */
1468
1469static void gsm_dlci_t1(struct timer_list *t)
1470{
1471 struct gsm_dlci *dlci = from_timer(dlci, t, t1);
1472 struct gsm_mux *gsm = dlci->gsm;
1473
1474 switch (dlci->state) {
1475 case DLCI_OPENING:
1476 dlci->retries--;
1477 if (dlci->retries) {
1478 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1479 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1480 } else if (!dlci->addr && gsm->control == (DM | PF)) {
1481 if (debug & 8)
1482 pr_info("DLCI %d opening in ADM mode.\n",
1483 dlci->addr);
1484 dlci->mode = DLCI_MODE_ADM;
1485 gsm_dlci_open(dlci);
1486 } else {
1487 gsm_dlci_close(dlci);
1488 }
1489
1490 break;
1491 case DLCI_CLOSING:
1492 dlci->retries--;
1493 if (dlci->retries) {
1494 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1495 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1496 } else
1497 gsm_dlci_close(dlci);
1498 break;
1499 }
1500}
1501
1502/**
1503 * gsm_dlci_begin_open - start channel open procedure
1504 * @dlci: DLCI to open
1505 *
1506 * Commence opening a DLCI from the Linux side. We issue SABM messages
1507 * to the modem which should then reply with a UA or ADM, at which point
1508 * we will move into open state. Opening is done asynchronously with retry
1509 * running off timers and the responses.
1510 */
1511
1512static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1513{
1514 struct gsm_mux *gsm = dlci->gsm;
1515 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1516 return;
1517 dlci->retries = gsm->n2;
1518 dlci->state = DLCI_OPENING;
1519 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1520 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1521}
1522
1523/**
1524 * gsm_dlci_begin_close - start channel open procedure
1525 * @dlci: DLCI to open
1526 *
1527 * Commence closing a DLCI from the Linux side. We issue DISC messages
1528 * to the modem which should then reply with a UA, at which point we
1529 * will move into closed state. Closing is done asynchronously with retry
1530 * off timers. We may also receive a DM reply from the other end which
1531 * indicates the channel was already closed.
1532 */
1533
1534static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1535{
1536 struct gsm_mux *gsm = dlci->gsm;
1537 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1538 return;
1539 dlci->retries = gsm->n2;
1540 dlci->state = DLCI_CLOSING;
1541 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1542 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1543}
1544
1545/**
1546 * gsm_dlci_data - data arrived
1547 * @dlci: channel
1548 * @data: block of bytes received
1549 * @len: length of received block
1550 *
1551 * A UI or UIH frame has arrived which contains data for a channel
1552 * other than the control channel. If the relevant virtual tty is
1553 * open we shovel the bits down it, if not we drop them.
1554 */
1555
1556static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
1557{
1558 /* krefs .. */
1559 struct tty_port *port = &dlci->port;
1560 struct tty_struct *tty;
1561 unsigned int modem = 0;
1562 int len = clen;
1563
1564 if (debug & 16)
1565 pr_debug("%d bytes for tty\n", len);
1566 switch (dlci->adaption) {
1567 /* Unsupported types */
1568 case 4: /* Packetised interruptible data */
1569 break;
1570 case 3: /* Packetised uininterruptible voice/data */
1571 break;
1572 case 2: /* Asynchronous serial with line state in each frame */
1573 while (gsm_read_ea(&modem, *data++) == 0) {
1574 len--;
1575 if (len == 0)
1576 return;
1577 }
1578 tty = tty_port_tty_get(port);
1579 if (tty) {
1580 gsm_process_modem(tty, dlci, modem, clen);
1581 tty_kref_put(tty);
1582 }
1583 /* Fall through */
1584 case 1: /* Line state will go via DLCI 0 controls only */
1585 default:
1586 tty_insert_flip_string(port, data, len);
1587 tty_flip_buffer_push(port);
1588 }
1589}
1590
1591/**
1592 * gsm_dlci_control - data arrived on control channel
1593 * @dlci: channel
1594 * @data: block of bytes received
1595 * @len: length of received block
1596 *
1597 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1598 * control channel. This should contain a command EA followed by
1599 * control data bytes. The command EA contains a command/response bit
1600 * and we divide up the work accordingly.
1601 */
1602
1603static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
1604{
1605 /* See what command is involved */
1606 unsigned int command = 0;
1607 while (len-- > 0) {
1608 if (gsm_read_ea(&command, *data++) == 1) {
1609 int clen = *data++;
1610 len--;
1611 /* FIXME: this is properly an EA */
1612 clen >>= 1;
1613 /* Malformed command ? */
1614 if (clen > len)
1615 return;
1616 if (command & 1)
1617 gsm_control_message(dlci->gsm, command,
1618 data, clen);
1619 else
1620 gsm_control_response(dlci->gsm, command,
1621 data, clen);
1622 return;
1623 }
1624 }
1625}
1626
1627/*
1628 * Allocate/Free DLCI channels
1629 */
1630
1631/**
1632 * gsm_dlci_alloc - allocate a DLCI
1633 * @gsm: GSM mux
1634 * @addr: address of the DLCI
1635 *
1636 * Allocate and install a new DLCI object into the GSM mux.
1637 *
1638 * FIXME: review locking races
1639 */
1640
1641static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1642{
1643 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1644 if (dlci == NULL)
1645 return NULL;
1646 spin_lock_init(&dlci->lock);
1647 mutex_init(&dlci->mutex);
1648 dlci->fifo = &dlci->_fifo;
1649 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1650 kfree(dlci);
1651 return NULL;
1652 }
1653
1654 skb_queue_head_init(&dlci->skb_list);
1655 timer_setup(&dlci->t1, gsm_dlci_t1, 0);
1656 tty_port_init(&dlci->port);
1657 dlci->port.ops = &gsm_port_ops;
1658 dlci->gsm = gsm;
1659 dlci->addr = addr;
1660 dlci->adaption = gsm->adaption;
1661 dlci->state = DLCI_CLOSED;
1662 if (addr)
1663 dlci->data = gsm_dlci_data;
1664 else
1665 dlci->data = gsm_dlci_command;
1666 gsm->dlci[addr] = dlci;
1667 return dlci;
1668}
1669
1670/**
1671 * gsm_dlci_free - free DLCI
1672 * @dlci: DLCI to free
1673 *
1674 * Free up a DLCI.
1675 *
1676 * Can sleep.
1677 */
1678static void gsm_dlci_free(struct tty_port *port)
1679{
1680 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
1681
1682 del_timer_sync(&dlci->t1);
1683 dlci->gsm->dlci[dlci->addr] = NULL;
1684 kfifo_free(dlci->fifo);
1685 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1686 dev_kfree_skb(dlci->skb);
1687 kfree(dlci);
1688}
1689
1690static inline void dlci_get(struct gsm_dlci *dlci)
1691{
1692 tty_port_get(&dlci->port);
1693}
1694
1695static inline void dlci_put(struct gsm_dlci *dlci)
1696{
1697 tty_port_put(&dlci->port);
1698}
1699
1700static void gsm_destroy_network(struct gsm_dlci *dlci);
1701
1702/**
1703 * gsm_dlci_release - release DLCI
1704 * @dlci: DLCI to destroy
1705 *
1706 * Release a DLCI. Actual free is deferred until either
1707 * mux is closed or tty is closed - whichever is last.
1708 *
1709 * Can sleep.
1710 */
1711static void gsm_dlci_release(struct gsm_dlci *dlci)
1712{
1713 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1714 if (tty) {
1715 mutex_lock(&dlci->mutex);
1716 gsm_destroy_network(dlci);
1717 mutex_unlock(&dlci->mutex);
1718
1719 tty_hangup(tty);
1720
1721 tty_port_tty_set(&dlci->port, NULL);
1722 tty_kref_put(tty);
1723 }
1724 dlci->state = DLCI_CLOSED;
1725 dlci_put(dlci);
1726}
1727
1728/*
1729 * LAPBish link layer logic
1730 */
1731
1732/**
1733 * gsm_queue - a GSM frame is ready to process
1734 * @gsm: pointer to our gsm mux
1735 *
1736 * At this point in time a frame has arrived and been demangled from
1737 * the line encoding. All the differences between the encodings have
1738 * been handled below us and the frame is unpacked into the structures.
1739 * The fcs holds the header FCS but any data FCS must be added here.
1740 */
1741
1742static void gsm_queue(struct gsm_mux *gsm)
1743{
1744 struct gsm_dlci *dlci;
1745 u8 cr;
1746 int address;
1747 /* We have to sneak a look at the packet body to do the FCS.
1748 A somewhat layering violation in the spec */
1749
1750 if ((gsm->control & ~PF) == UI)
1751 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1752 if (gsm->encoding == 0) {
1753 /* WARNING: gsm->received_fcs is used for
1754 gsm->encoding = 0 only.
1755 In this case it contain the last piece of data
1756 required to generate final CRC */
1757 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1758 }
1759 if (gsm->fcs != GOOD_FCS) {
1760 gsm->bad_fcs++;
1761 if (debug & 4)
1762 pr_debug("BAD FCS %02x\n", gsm->fcs);
1763 return;
1764 }
1765 address = gsm->address >> 1;
1766 if (address >= NUM_DLCI)
1767 goto invalid;
1768
1769 cr = gsm->address & 1; /* C/R bit */
1770
1771 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1772
1773 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1774 dlci = gsm->dlci[address];
1775
1776 switch (gsm->control) {
1777 case SABM|PF:
1778 if (cr == 0)
1779 goto invalid;
1780 if (dlci == NULL)
1781 dlci = gsm_dlci_alloc(gsm, address);
1782 if (dlci == NULL)
1783 return;
1784 if (dlci->dead)
1785 gsm_response(gsm, address, DM);
1786 else {
1787 gsm_response(gsm, address, UA);
1788 gsm_dlci_open(dlci);
1789 }
1790 break;
1791 case DISC|PF:
1792 if (cr == 0)
1793 goto invalid;
1794 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1795 gsm_response(gsm, address, DM);
1796 return;
1797 }
1798 /* Real close complete */
1799 gsm_response(gsm, address, UA);
1800 gsm_dlci_close(dlci);
1801 break;
1802 case UA:
1803 case UA|PF:
1804 if (cr == 0 || dlci == NULL)
1805 break;
1806 switch (dlci->state) {
1807 case DLCI_CLOSING:
1808 gsm_dlci_close(dlci);
1809 break;
1810 case DLCI_OPENING:
1811 gsm_dlci_open(dlci);
1812 break;
1813 }
1814 break;
1815 case DM: /* DM can be valid unsolicited */
1816 case DM|PF:
1817 if (cr)
1818 goto invalid;
1819 if (dlci == NULL)
1820 return;
1821 gsm_dlci_close(dlci);
1822 break;
1823 case UI:
1824 case UI|PF:
1825 case UIH:
1826 case UIH|PF:
1827#if 0
1828 if (cr)
1829 goto invalid;
1830#endif
1831 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1832 gsm_command(gsm, address, DM|PF);
1833 return;
1834 }
1835 dlci->data(dlci, gsm->buf, gsm->len);
1836 break;
1837 default:
1838 goto invalid;
1839 }
1840 return;
1841invalid:
1842 gsm->malformed++;
1843 return;
1844}
1845
1846
1847/**
1848 * gsm0_receive - perform processing for non-transparency
1849 * @gsm: gsm data for this ldisc instance
1850 * @c: character
1851 *
1852 * Receive bytes in gsm mode 0
1853 */
1854
1855static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1856{
1857 unsigned int len;
1858
1859 switch (gsm->state) {
1860 case GSM_SEARCH: /* SOF marker */
1861 if (c == GSM0_SOF) {
1862 gsm->state = GSM_ADDRESS;
1863 gsm->address = 0;
1864 gsm->len = 0;
1865 gsm->fcs = INIT_FCS;
1866 }
1867 break;
1868 case GSM_ADDRESS: /* Address EA */
1869 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1870 if (gsm_read_ea(&gsm->address, c))
1871 gsm->state = GSM_CONTROL;
1872 break;
1873 case GSM_CONTROL: /* Control Byte */
1874 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1875 gsm->control = c;
1876 gsm->state = GSM_LEN0;
1877 break;
1878 case GSM_LEN0: /* Length EA */
1879 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1880 if (gsm_read_ea(&gsm->len, c)) {
1881 if (gsm->len > gsm->mru) {
1882 gsm->bad_size++;
1883 gsm->state = GSM_SEARCH;
1884 break;
1885 }
1886 gsm->count = 0;
1887 if (!gsm->len)
1888 gsm->state = GSM_FCS;
1889 else
1890 gsm->state = GSM_DATA;
1891 break;
1892 }
1893 gsm->state = GSM_LEN1;
1894 break;
1895 case GSM_LEN1:
1896 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1897 len = c;
1898 gsm->len |= len << 7;
1899 if (gsm->len > gsm->mru) {
1900 gsm->bad_size++;
1901 gsm->state = GSM_SEARCH;
1902 break;
1903 }
1904 gsm->count = 0;
1905 if (!gsm->len)
1906 gsm->state = GSM_FCS;
1907 else
1908 gsm->state = GSM_DATA;
1909 break;
1910 case GSM_DATA: /* Data */
1911 gsm->buf[gsm->count++] = c;
1912 if (gsm->count == gsm->len)
1913 gsm->state = GSM_FCS;
1914 break;
1915 case GSM_FCS: /* FCS follows the packet */
1916 gsm->received_fcs = c;
1917 gsm_queue(gsm);
1918 gsm->state = GSM_SSOF;
1919 break;
1920 case GSM_SSOF:
1921 if (c == GSM0_SOF) {
1922 gsm->state = GSM_SEARCH;
1923 break;
1924 }
1925 break;
1926 }
1927}
1928
1929/**
1930 * gsm1_receive - perform processing for non-transparency
1931 * @gsm: gsm data for this ldisc instance
1932 * @c: character
1933 *
1934 * Receive bytes in mode 1 (Advanced option)
1935 */
1936
1937static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1938{
1939 if (c == GSM1_SOF) {
1940 /* EOF is only valid in frame if we have got to the data state
1941 and received at least one byte (the FCS) */
1942 if (gsm->state == GSM_DATA && gsm->count) {
1943 /* Extract the FCS */
1944 gsm->count--;
1945 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1946 gsm->len = gsm->count;
1947 gsm_queue(gsm);
1948 gsm->state = GSM_START;
1949 return;
1950 }
1951 /* Any partial frame was a runt so go back to start */
1952 if (gsm->state != GSM_START) {
1953 gsm->malformed++;
1954 gsm->state = GSM_START;
1955 }
1956 /* A SOF in GSM_START means we are still reading idling or
1957 framing bytes */
1958 return;
1959 }
1960
1961 if (c == GSM1_ESCAPE) {
1962 gsm->escape = 1;
1963 return;
1964 }
1965
1966 /* Only an unescaped SOF gets us out of GSM search */
1967 if (gsm->state == GSM_SEARCH)
1968 return;
1969
1970 if (gsm->escape) {
1971 c ^= GSM1_ESCAPE_BITS;
1972 gsm->escape = 0;
1973 }
1974 switch (gsm->state) {
1975 case GSM_START: /* First byte after SOF */
1976 gsm->address = 0;
1977 gsm->state = GSM_ADDRESS;
1978 gsm->fcs = INIT_FCS;
1979 /* Fall through */
1980 case GSM_ADDRESS: /* Address continuation */
1981 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1982 if (gsm_read_ea(&gsm->address, c))
1983 gsm->state = GSM_CONTROL;
1984 break;
1985 case GSM_CONTROL: /* Control Byte */
1986 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1987 gsm->control = c;
1988 gsm->count = 0;
1989 gsm->state = GSM_DATA;
1990 break;
1991 case GSM_DATA: /* Data */
1992 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
1993 gsm->state = GSM_OVERRUN;
1994 gsm->bad_size++;
1995 } else
1996 gsm->buf[gsm->count++] = c;
1997 break;
1998 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
1999 break;
2000 }
2001}
2002
2003/**
2004 * gsm_error - handle tty error
2005 * @gsm: ldisc data
2006 * @data: byte received (may be invalid)
2007 * @flag: error received
2008 *
2009 * Handle an error in the receipt of data for a frame. Currently we just
2010 * go back to hunting for a SOF.
2011 *
2012 * FIXME: better diagnostics ?
2013 */
2014
2015static void gsm_error(struct gsm_mux *gsm,
2016 unsigned char data, unsigned char flag)
2017{
2018 gsm->state = GSM_SEARCH;
2019 gsm->io_error++;
2020}
2021
2022static int gsm_disconnect(struct gsm_mux *gsm)
2023{
2024 struct gsm_dlci *dlci = gsm->dlci[0];
2025 struct gsm_control *gc;
2026
2027 if (!dlci)
2028 return 0;
2029
2030 /* In theory disconnecting DLCI 0 is sufficient but for some
2031 modems this is apparently not the case. */
2032 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2033 if (gc)
2034 gsm_control_wait(gsm, gc);
2035
2036 del_timer_sync(&gsm->t2_timer);
2037 /* Now we are sure T2 has stopped */
2038
2039 gsm_dlci_begin_close(dlci);
2040 wait_event_interruptible(gsm->event,
2041 dlci->state == DLCI_CLOSED);
2042
2043 if (signal_pending(current))
2044 return -EINTR;
2045
2046 return 0;
2047}
2048
2049/**
2050 * gsm_cleanup_mux - generic GSM protocol cleanup
2051 * @gsm: our mux
2052 *
2053 * Clean up the bits of the mux which are the same for all framing
2054 * protocols. Remove the mux from the mux table, stop all the timers
2055 * and then shut down each device hanging up the channels as we go.
2056 */
2057
2058static void gsm_cleanup_mux(struct gsm_mux *gsm)
2059{
2060 int i;
2061 struct gsm_dlci *dlci = gsm->dlci[0];
2062 struct gsm_msg *txq, *ntxq;
2063
2064 gsm->dead = 1;
2065
2066 spin_lock(&gsm_mux_lock);
2067 for (i = 0; i < MAX_MUX; i++) {
2068 if (gsm_mux[i] == gsm) {
2069 gsm_mux[i] = NULL;
2070 break;
2071 }
2072 }
2073 spin_unlock(&gsm_mux_lock);
2074 /* open failed before registering => nothing to do */
2075 if (i == MAX_MUX)
2076 return;
2077
2078 del_timer_sync(&gsm->t2_timer);
2079 /* Now we are sure T2 has stopped */
2080 if (dlci)
2081 dlci->dead = 1;
2082
2083 /* Free up any link layer users */
2084 mutex_lock(&gsm->mutex);
2085 for (i = 0; i < NUM_DLCI; i++)
2086 if (gsm->dlci[i])
2087 gsm_dlci_release(gsm->dlci[i]);
2088 mutex_unlock(&gsm->mutex);
2089 /* Now wipe the queues */
2090 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2091 kfree(txq);
2092 INIT_LIST_HEAD(&gsm->tx_list);
2093}
2094
2095/**
2096 * gsm_activate_mux - generic GSM setup
2097 * @gsm: our mux
2098 *
2099 * Set up the bits of the mux which are the same for all framing
2100 * protocols. Add the mux to the mux table so it can be opened and
2101 * finally kick off connecting to DLCI 0 on the modem.
2102 */
2103
2104static int gsm_activate_mux(struct gsm_mux *gsm)
2105{
2106 struct gsm_dlci *dlci;
2107 int i = 0;
2108
2109 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
2110 init_waitqueue_head(&gsm->event);
2111 spin_lock_init(&gsm->control_lock);
2112 spin_lock_init(&gsm->tx_lock);
2113
2114 if (gsm->encoding == 0)
2115 gsm->receive = gsm0_receive;
2116 else
2117 gsm->receive = gsm1_receive;
2118 gsm->error = gsm_error;
2119
2120 spin_lock(&gsm_mux_lock);
2121 for (i = 0; i < MAX_MUX; i++) {
2122 if (gsm_mux[i] == NULL) {
2123 gsm->num = i;
2124 gsm_mux[i] = gsm;
2125 break;
2126 }
2127 }
2128 spin_unlock(&gsm_mux_lock);
2129 if (i == MAX_MUX)
2130 return -EBUSY;
2131
2132 dlci = gsm_dlci_alloc(gsm, 0);
2133 if (dlci == NULL)
2134 return -ENOMEM;
2135 gsm->dead = 0; /* Tty opens are now permissible */
2136 return 0;
2137}
2138
2139/**
2140 * gsm_free_mux - free up a mux
2141 * @mux: mux to free
2142 *
2143 * Dispose of allocated resources for a dead mux
2144 */
2145static void gsm_free_mux(struct gsm_mux *gsm)
2146{
2147 kfree(gsm->txframe);
2148 kfree(gsm->buf);
2149 kfree(gsm);
2150}
2151
2152/**
2153 * gsm_free_muxr - free up a mux
2154 * @mux: mux to free
2155 *
2156 * Dispose of allocated resources for a dead mux
2157 */
2158static void gsm_free_muxr(struct kref *ref)
2159{
2160 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2161 gsm_free_mux(gsm);
2162}
2163
2164static inline void mux_get(struct gsm_mux *gsm)
2165{
2166 kref_get(&gsm->ref);
2167}
2168
2169static inline void mux_put(struct gsm_mux *gsm)
2170{
2171 kref_put(&gsm->ref, gsm_free_muxr);
2172}
2173
2174static inline unsigned int mux_num_to_base(struct gsm_mux *gsm)
2175{
2176 return gsm->num * NUM_DLCI;
2177}
2178
2179static inline unsigned int mux_line_to_num(unsigned int line)
2180{
2181 return line / NUM_DLCI;
2182}
2183
2184/**
2185 * gsm_alloc_mux - allocate a mux
2186 *
2187 * Creates a new mux ready for activation.
2188 */
2189
2190static struct gsm_mux *gsm_alloc_mux(void)
2191{
2192 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2193 if (gsm == NULL)
2194 return NULL;
2195 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2196 if (gsm->buf == NULL) {
2197 kfree(gsm);
2198 return NULL;
2199 }
2200 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2201 if (gsm->txframe == NULL) {
2202 kfree(gsm->buf);
2203 kfree(gsm);
2204 return NULL;
2205 }
2206 spin_lock_init(&gsm->lock);
2207 mutex_init(&gsm->mutex);
2208 kref_init(&gsm->ref);
2209 INIT_LIST_HEAD(&gsm->tx_list);
2210
2211 gsm->t1 = T1;
2212 gsm->t2 = T2;
2213 gsm->n2 = N2;
2214 gsm->ftype = UIH;
2215 gsm->adaption = 1;
2216 gsm->encoding = 1;
2217 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2218 gsm->mtu = 64;
2219 gsm->dead = 1; /* Avoid early tty opens */
2220
2221 return gsm;
2222}
2223
2224static void gsm_copy_config_values(struct gsm_mux *gsm,
2225 struct gsm_config *c)
2226{
2227 memset(c, 0, sizeof(*c));
2228 c->adaption = gsm->adaption;
2229 c->encapsulation = gsm->encoding;
2230 c->initiator = gsm->initiator;
2231 c->t1 = gsm->t1;
2232 c->t2 = gsm->t2;
2233 c->t3 = 0; /* Not supported */
2234 c->n2 = gsm->n2;
2235 if (gsm->ftype == UIH)
2236 c->i = 1;
2237 else
2238 c->i = 2;
2239 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i);
2240 c->mru = gsm->mru;
2241 c->mtu = gsm->mtu;
2242 c->k = 0;
2243}
2244
2245static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
2246{
2247 int need_close = 0;
2248 int need_restart = 0;
2249
2250 /* Stuff we don't support yet - UI or I frame transport, windowing */
2251 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2252 return -EOPNOTSUPP;
2253 /* Check the MRU/MTU range looks sane */
2254 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2255 return -EINVAL;
2256 if (c->n2 < 3)
2257 return -EINVAL;
2258 if (c->encapsulation > 1) /* Basic, advanced, no I */
2259 return -EINVAL;
2260 if (c->initiator > 1)
2261 return -EINVAL;
2262 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2263 return -EINVAL;
2264 /*
2265 * See what is needed for reconfiguration
2266 */
2267
2268 /* Timing fields */
2269 if (c->t1 != 0 && c->t1 != gsm->t1)
2270 need_restart = 1;
2271 if (c->t2 != 0 && c->t2 != gsm->t2)
2272 need_restart = 1;
2273 if (c->encapsulation != gsm->encoding)
2274 need_restart = 1;
2275 if (c->adaption != gsm->adaption)
2276 need_restart = 1;
2277 /* Requires care */
2278 if (c->initiator != gsm->initiator)
2279 need_close = 1;
2280 if (c->mru != gsm->mru)
2281 need_restart = 1;
2282 if (c->mtu != gsm->mtu)
2283 need_restart = 1;
2284
2285 /*
2286 * Close down what is needed, restart and initiate the new
2287 * configuration
2288 */
2289
2290 if (need_close || need_restart) {
2291 int ret;
2292
2293 ret = gsm_disconnect(gsm);
2294
2295 if (ret)
2296 return ret;
2297 }
2298 if (need_restart)
2299 gsm_cleanup_mux(gsm);
2300
2301 gsm->initiator = c->initiator;
2302 gsm->mru = c->mru;
2303 gsm->mtu = c->mtu;
2304 gsm->encoding = c->encapsulation;
2305 gsm->adaption = c->adaption;
2306 gsm->n2 = c->n2;
2307
2308 if (c->i == 1)
2309 gsm->ftype = UIH;
2310 else if (c->i == 2)
2311 gsm->ftype = UI;
2312
2313 if (c->t1)
2314 gsm->t1 = c->t1;
2315 if (c->t2)
2316 gsm->t2 = c->t2;
2317
2318 /*
2319 * FIXME: We need to separate activation/deactivation from adding
2320 * and removing from the mux array
2321 */
2322 if (need_restart)
2323 gsm_activate_mux(gsm);
2324 if (gsm->initiator && need_close)
2325 gsm_dlci_begin_open(gsm->dlci[0]);
2326 return 0;
2327}
2328
2329/**
2330 * gsmld_output - write to link
2331 * @gsm: our mux
2332 * @data: bytes to output
2333 * @len: size
2334 *
2335 * Write a block of data from the GSM mux to the data channel. This
2336 * will eventually be serialized from above but at the moment isn't.
2337 */
2338
2339static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2340{
2341 if (tty_write_room(gsm->tty) < len) {
2342 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2343 return -ENOSPC;
2344 }
2345 if (debug & 4)
2346 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2347 data, len);
2348 gsm->tty->ops->write(gsm->tty, data, len);
2349 return len;
2350}
2351
2352/**
2353 * gsmld_attach_gsm - mode set up
2354 * @tty: our tty structure
2355 * @gsm: our mux
2356 *
2357 * Set up the MUX for basic mode and commence connecting to the
2358 * modem. Currently called from the line discipline set up but
2359 * will need moving to an ioctl path.
2360 */
2361
2362static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2363{
2364 unsigned int base;
2365 int ret, i;
2366
2367 gsm->tty = tty_kref_get(tty);
2368 gsm->output = gsmld_output;
2369 ret = gsm_activate_mux(gsm);
2370 if (ret != 0)
2371 tty_kref_put(gsm->tty);
2372 else {
2373 /* Don't register device 0 - this is the control channel and not
2374 a usable tty interface */
2375 base = mux_num_to_base(gsm); /* Base for this MUX */
2376 for (i = 1; i < NUM_DLCI; i++)
2377 tty_register_device(gsm_tty_driver, base + i, NULL);
2378 }
2379 return ret;
2380}
2381
2382
2383/**
2384 * gsmld_detach_gsm - stop doing 0710 mux
2385 * @tty: tty attached to the mux
2386 * @gsm: mux
2387 *
2388 * Shutdown and then clean up the resources used by the line discipline
2389 */
2390
2391static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2392{
2393 unsigned int base = mux_num_to_base(gsm); /* Base for this MUX */
2394 int i;
2395
2396 WARN_ON(tty != gsm->tty);
2397 for (i = 1; i < NUM_DLCI; i++)
2398 tty_unregister_device(gsm_tty_driver, base + i);
2399 gsm_cleanup_mux(gsm);
2400 tty_kref_put(gsm->tty);
2401 gsm->tty = NULL;
2402}
2403
2404static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2405 char *fp, int count)
2406{
2407 struct gsm_mux *gsm = tty->disc_data;
2408 const unsigned char *dp;
2409 char *f;
2410 int i;
2411 char flags = TTY_NORMAL;
2412
2413 if (debug & 4)
2414 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2415 cp, count);
2416
2417 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2418 if (f)
2419 flags = *f++;
2420 switch (flags) {
2421 case TTY_NORMAL:
2422 gsm->receive(gsm, *dp);
2423 break;
2424 case TTY_OVERRUN:
2425 case TTY_BREAK:
2426 case TTY_PARITY:
2427 case TTY_FRAME:
2428 gsm->error(gsm, *dp, flags);
2429 break;
2430 default:
2431 WARN_ONCE(1, "%s: unknown flag %d\n",
2432 tty_name(tty), flags);
2433 break;
2434 }
2435 }
2436 /* FASYNC if needed ? */
2437 /* If clogged call tty_throttle(tty); */
2438}
2439
2440/**
2441 * gsmld_flush_buffer - clean input queue
2442 * @tty: terminal device
2443 *
2444 * Flush the input buffer. Called when the line discipline is
2445 * being closed, when the tty layer wants the buffer flushed (eg
2446 * at hangup).
2447 */
2448
2449static void gsmld_flush_buffer(struct tty_struct *tty)
2450{
2451}
2452
2453/**
2454 * gsmld_close - close the ldisc for this tty
2455 * @tty: device
2456 *
2457 * Called from the terminal layer when this line discipline is
2458 * being shut down, either because of a close or becsuse of a
2459 * discipline change. The function will not be called while other
2460 * ldisc methods are in progress.
2461 */
2462
2463static void gsmld_close(struct tty_struct *tty)
2464{
2465 struct gsm_mux *gsm = tty->disc_data;
2466
2467 gsmld_detach_gsm(tty, gsm);
2468
2469 gsmld_flush_buffer(tty);
2470 /* Do other clean up here */
2471 mux_put(gsm);
2472}
2473
2474/**
2475 * gsmld_open - open an ldisc
2476 * @tty: terminal to open
2477 *
2478 * Called when this line discipline is being attached to the
2479 * terminal device. Can sleep. Called serialized so that no
2480 * other events will occur in parallel. No further open will occur
2481 * until a close.
2482 */
2483
2484static int gsmld_open(struct tty_struct *tty)
2485{
2486 struct gsm_mux *gsm;
2487 int ret;
2488
2489 if (tty->ops->write == NULL)
2490 return -EINVAL;
2491
2492 /* Attach our ldisc data */
2493 gsm = gsm_alloc_mux();
2494 if (gsm == NULL)
2495 return -ENOMEM;
2496
2497 tty->disc_data = gsm;
2498 tty->receive_room = 65536;
2499
2500 /* Attach the initial passive connection */
2501 gsm->encoding = 1;
2502
2503 ret = gsmld_attach_gsm(tty, gsm);
2504 if (ret != 0) {
2505 gsm_cleanup_mux(gsm);
2506 mux_put(gsm);
2507 }
2508 return ret;
2509}
2510
2511/**
2512 * gsmld_write_wakeup - asynchronous I/O notifier
2513 * @tty: tty device
2514 *
2515 * Required for the ptys, serial driver etc. since processes
2516 * that attach themselves to the master and rely on ASYNC
2517 * IO must be woken up
2518 */
2519
2520static void gsmld_write_wakeup(struct tty_struct *tty)
2521{
2522 struct gsm_mux *gsm = tty->disc_data;
2523 unsigned long flags;
2524
2525 /* Queue poll */
2526 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2527 spin_lock_irqsave(&gsm->tx_lock, flags);
2528 gsm_data_kick(gsm);
2529 if (gsm->tx_bytes < TX_THRESH_LO) {
2530 gsm_dlci_data_sweep(gsm);
2531 }
2532 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2533}
2534
2535/**
2536 * gsmld_read - read function for tty
2537 * @tty: tty device
2538 * @file: file object
2539 * @buf: userspace buffer pointer
2540 * @nr: size of I/O
2541 *
2542 * Perform reads for the line discipline. We are guaranteed that the
2543 * line discipline will not be closed under us but we may get multiple
2544 * parallel readers and must handle this ourselves. We may also get
2545 * a hangup. Always called in user context, may sleep.
2546 *
2547 * This code must be sure never to sleep through a hangup.
2548 */
2549
2550static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2551 unsigned char __user *buf, size_t nr)
2552{
2553 return -EOPNOTSUPP;
2554}
2555
2556/**
2557 * gsmld_write - write function for tty
2558 * @tty: tty device
2559 * @file: file object
2560 * @buf: userspace buffer pointer
2561 * @nr: size of I/O
2562 *
2563 * Called when the owner of the device wants to send a frame
2564 * itself (or some other control data). The data is transferred
2565 * as-is and must be properly framed and checksummed as appropriate
2566 * by userspace. Frames are either sent whole or not at all as this
2567 * avoids pain user side.
2568 */
2569
2570static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2571 const unsigned char *buf, size_t nr)
2572{
2573 int space = tty_write_room(tty);
2574 if (space >= nr)
2575 return tty->ops->write(tty, buf, nr);
2576 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2577 return -ENOBUFS;
2578}
2579
2580/**
2581 * gsmld_poll - poll method for N_GSM0710
2582 * @tty: terminal device
2583 * @file: file accessing it
2584 * @wait: poll table
2585 *
2586 * Called when the line discipline is asked to poll() for data or
2587 * for special events. This code is not serialized with respect to
2588 * other events save open/close.
2589 *
2590 * This code must be sure never to sleep through a hangup.
2591 * Called without the kernel lock held - fine
2592 */
2593
2594static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
2595 poll_table *wait)
2596{
2597 __poll_t mask = 0;
2598 struct gsm_mux *gsm = tty->disc_data;
2599
2600 poll_wait(file, &tty->read_wait, wait);
2601 poll_wait(file, &tty->write_wait, wait);
2602 if (tty_hung_up_p(file))
2603 mask |= EPOLLHUP;
2604 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2605 mask |= EPOLLOUT | EPOLLWRNORM;
2606 if (gsm->dead)
2607 mask |= EPOLLHUP;
2608 return mask;
2609}
2610
2611static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2612 unsigned int cmd, unsigned long arg)
2613{
2614 struct gsm_config c;
2615 struct gsm_mux *gsm = tty->disc_data;
2616 unsigned int base;
2617
2618 switch (cmd) {
2619 case GSMIOC_GETCONF:
2620 gsm_copy_config_values(gsm, &c);
2621 if (copy_to_user((void *)arg, &c, sizeof(c)))
2622 return -EFAULT;
2623 return 0;
2624 case GSMIOC_SETCONF:
2625 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2626 return -EFAULT;
2627 return gsm_config(gsm, &c);
2628 case GSMIOC_GETFIRST:
2629 base = mux_num_to_base(gsm);
2630 return put_user(base + 1, (__u32 __user *)arg);
2631 default:
2632 return n_tty_ioctl_helper(tty, file, cmd, arg);
2633 }
2634}
2635
2636/*
2637 * Network interface
2638 *
2639 */
2640
2641static int gsm_mux_net_open(struct net_device *net)
2642{
2643 pr_debug("%s called\n", __func__);
2644 netif_start_queue(net);
2645 return 0;
2646}
2647
2648static int gsm_mux_net_close(struct net_device *net)
2649{
2650 netif_stop_queue(net);
2651 return 0;
2652}
2653
2654static void dlci_net_free(struct gsm_dlci *dlci)
2655{
2656 if (!dlci->net) {
2657 WARN_ON(1);
2658 return;
2659 }
2660 dlci->adaption = dlci->prev_adaption;
2661 dlci->data = dlci->prev_data;
2662 free_netdev(dlci->net);
2663 dlci->net = NULL;
2664}
2665static void net_free(struct kref *ref)
2666{
2667 struct gsm_mux_net *mux_net;
2668 struct gsm_dlci *dlci;
2669
2670 mux_net = container_of(ref, struct gsm_mux_net, ref);
2671 dlci = mux_net->dlci;
2672
2673 if (dlci->net) {
2674 unregister_netdev(dlci->net);
2675 dlci_net_free(dlci);
2676 }
2677}
2678
2679static inline void muxnet_get(struct gsm_mux_net *mux_net)
2680{
2681 kref_get(&mux_net->ref);
2682}
2683
2684static inline void muxnet_put(struct gsm_mux_net *mux_net)
2685{
2686 kref_put(&mux_net->ref, net_free);
2687}
2688
2689static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
2690 struct net_device *net)
2691{
2692 struct gsm_mux_net *mux_net = netdev_priv(net);
2693 struct gsm_dlci *dlci = mux_net->dlci;
2694 muxnet_get(mux_net);
2695
2696 skb_queue_head(&dlci->skb_list, skb);
2697 net->stats.tx_packets++;
2698 net->stats.tx_bytes += skb->len;
2699 gsm_dlci_data_kick(dlci);
2700 /* And tell the kernel when the last transmit started. */
2701 netif_trans_update(net);
2702 muxnet_put(mux_net);
2703 return NETDEV_TX_OK;
2704}
2705
2706/* called when a packet did not ack after watchdogtimeout */
2707static void gsm_mux_net_tx_timeout(struct net_device *net)
2708{
2709 /* Tell syslog we are hosed. */
2710 dev_dbg(&net->dev, "Tx timed out.\n");
2711
2712 /* Update statistics */
2713 net->stats.tx_errors++;
2714}
2715
2716static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2717 const unsigned char *in_buf, int size)
2718{
2719 struct net_device *net = dlci->net;
2720 struct sk_buff *skb;
2721 struct gsm_mux_net *mux_net = netdev_priv(net);
2722 muxnet_get(mux_net);
2723
2724 /* Allocate an sk_buff */
2725 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2726 if (!skb) {
2727 /* We got no receive buffer. */
2728 net->stats.rx_dropped++;
2729 muxnet_put(mux_net);
2730 return;
2731 }
2732 skb_reserve(skb, NET_IP_ALIGN);
2733 skb_put_data(skb, in_buf, size);
2734
2735 skb->dev = net;
2736 skb->protocol = htons(ETH_P_IP);
2737
2738 /* Ship it off to the kernel */
2739 netif_rx(skb);
2740
2741 /* update out statistics */
2742 net->stats.rx_packets++;
2743 net->stats.rx_bytes += size;
2744 muxnet_put(mux_net);
2745 return;
2746}
2747
2748static void gsm_mux_net_init(struct net_device *net)
2749{
2750 static const struct net_device_ops gsm_netdev_ops = {
2751 .ndo_open = gsm_mux_net_open,
2752 .ndo_stop = gsm_mux_net_close,
2753 .ndo_start_xmit = gsm_mux_net_start_xmit,
2754 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2755 };
2756
2757 net->netdev_ops = &gsm_netdev_ops;
2758
2759 /* fill in the other fields */
2760 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2761 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2762 net->type = ARPHRD_NONE;
2763 net->tx_queue_len = 10;
2764}
2765
2766
2767/* caller holds the dlci mutex */
2768static void gsm_destroy_network(struct gsm_dlci *dlci)
2769{
2770 struct gsm_mux_net *mux_net;
2771
2772 pr_debug("destroy network interface");
2773 if (!dlci->net)
2774 return;
2775 mux_net = netdev_priv(dlci->net);
2776 muxnet_put(mux_net);
2777}
2778
2779
2780/* caller holds the dlci mutex */
2781static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2782{
2783 char *netname;
2784 int retval = 0;
2785 struct net_device *net;
2786 struct gsm_mux_net *mux_net;
2787
2788 if (!capable(CAP_NET_ADMIN))
2789 return -EPERM;
2790
2791 /* Already in a non tty mode */
2792 if (dlci->adaption > 2)
2793 return -EBUSY;
2794
2795 if (nc->protocol != htons(ETH_P_IP))
2796 return -EPROTONOSUPPORT;
2797
2798 if (nc->adaption != 3 && nc->adaption != 4)
2799 return -EPROTONOSUPPORT;
2800
2801 pr_debug("create network interface");
2802
2803 netname = "gsm%d";
2804 if (nc->if_name[0] != '\0')
2805 netname = nc->if_name;
2806 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
2807 NET_NAME_UNKNOWN, gsm_mux_net_init);
2808 if (!net) {
2809 pr_err("alloc_netdev failed");
2810 return -ENOMEM;
2811 }
2812 net->mtu = dlci->gsm->mtu;
2813 net->min_mtu = 8;
2814 net->max_mtu = dlci->gsm->mtu;
2815 mux_net = netdev_priv(net);
2816 mux_net->dlci = dlci;
2817 kref_init(&mux_net->ref);
2818 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2819
2820 /* reconfigure dlci for network */
2821 dlci->prev_adaption = dlci->adaption;
2822 dlci->prev_data = dlci->data;
2823 dlci->adaption = nc->adaption;
2824 dlci->data = gsm_mux_rx_netchar;
2825 dlci->net = net;
2826
2827 pr_debug("register netdev");
2828 retval = register_netdev(net);
2829 if (retval) {
2830 pr_err("network register fail %d\n", retval);
2831 dlci_net_free(dlci);
2832 return retval;
2833 }
2834 return net->ifindex; /* return network index */
2835}
2836
2837/* Line discipline for real tty */
2838static struct tty_ldisc_ops tty_ldisc_packet = {
2839 .owner = THIS_MODULE,
2840 .magic = TTY_LDISC_MAGIC,
2841 .name = "n_gsm",
2842 .open = gsmld_open,
2843 .close = gsmld_close,
2844 .flush_buffer = gsmld_flush_buffer,
2845 .read = gsmld_read,
2846 .write = gsmld_write,
2847 .ioctl = gsmld_ioctl,
2848 .poll = gsmld_poll,
2849 .receive_buf = gsmld_receive_buf,
2850 .write_wakeup = gsmld_write_wakeup
2851};
2852
2853/*
2854 * Virtual tty side
2855 */
2856
2857#define TX_SIZE 512
2858
2859static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2860{
2861 u8 modembits[5];
2862 struct gsm_control *ctrl;
2863 int len = 2;
2864
2865 if (brk)
2866 len++;
2867
2868 modembits[0] = len << 1 | EA; /* Data bytes */
2869 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2870 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2871 if (brk)
2872 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2873 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2874 if (ctrl == NULL)
2875 return -ENOMEM;
2876 return gsm_control_wait(dlci->gsm, ctrl);
2877}
2878
2879static int gsm_carrier_raised(struct tty_port *port)
2880{
2881 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2882 struct gsm_mux *gsm = dlci->gsm;
2883
2884 /* Not yet open so no carrier info */
2885 if (dlci->state != DLCI_OPEN)
2886 return 0;
2887 if (debug & 2)
2888 return 1;
2889
2890 /*
2891 * Basic mode with control channel in ADM mode may not respond
2892 * to CMD_MSC at all and modem_rx is empty.
2893 */
2894 if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM &&
2895 !dlci->modem_rx)
2896 return 1;
2897
2898 return dlci->modem_rx & TIOCM_CD;
2899}
2900
2901static void gsm_dtr_rts(struct tty_port *port, int onoff)
2902{
2903 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2904 unsigned int modem_tx = dlci->modem_tx;
2905 if (onoff)
2906 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2907 else
2908 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2909 if (modem_tx != dlci->modem_tx) {
2910 dlci->modem_tx = modem_tx;
2911 gsmtty_modem_update(dlci, 0);
2912 }
2913}
2914
2915static const struct tty_port_operations gsm_port_ops = {
2916 .carrier_raised = gsm_carrier_raised,
2917 .dtr_rts = gsm_dtr_rts,
2918 .destruct = gsm_dlci_free,
2919};
2920
2921static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
2922{
2923 struct gsm_mux *gsm;
2924 struct gsm_dlci *dlci;
2925 unsigned int line = tty->index;
2926 unsigned int mux = mux_line_to_num(line);
2927 bool alloc = false;
2928 int ret;
2929
2930 line = line & 0x3F;
2931
2932 if (mux >= MAX_MUX)
2933 return -ENXIO;
2934 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2935 if (gsm_mux[mux] == NULL)
2936 return -EUNATCH;
2937 if (line == 0 || line > 61) /* 62/63 reserved */
2938 return -ECHRNG;
2939 gsm = gsm_mux[mux];
2940 if (gsm->dead)
2941 return -EL2HLT;
2942 /* If DLCI 0 is not yet fully open return an error.
2943 This is ok from a locking
2944 perspective as we don't have to worry about this
2945 if DLCI0 is lost */
2946 mutex_lock(&gsm->mutex);
2947 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
2948 mutex_unlock(&gsm->mutex);
2949 return -EL2NSYNC;
2950 }
2951 dlci = gsm->dlci[line];
2952 if (dlci == NULL) {
2953 alloc = true;
2954 dlci = gsm_dlci_alloc(gsm, line);
2955 }
2956 if (dlci == NULL) {
2957 mutex_unlock(&gsm->mutex);
2958 return -ENOMEM;
2959 }
2960 ret = tty_port_install(&dlci->port, driver, tty);
2961 if (ret) {
2962 if (alloc)
2963 dlci_put(dlci);
2964 mutex_unlock(&gsm->mutex);
2965 return ret;
2966 }
2967
2968 dlci_get(dlci);
2969 dlci_get(gsm->dlci[0]);
2970 mux_get(gsm);
2971 tty->driver_data = dlci;
2972 mutex_unlock(&gsm->mutex);
2973
2974 return 0;
2975}
2976
2977static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2978{
2979 struct gsm_dlci *dlci = tty->driver_data;
2980 struct tty_port *port = &dlci->port;
2981
2982 port->count++;
2983 tty_port_tty_set(port, tty);
2984
2985 dlci->modem_rx = 0;
2986 /* We could in theory open and close before we wait - eg if we get
2987 a DM straight back. This is ok as that will have caused a hangup */
2988 tty_port_set_initialized(port, 1);
2989 /* Start sending off SABM messages */
2990 gsm_dlci_begin_open(dlci);
2991 /* And wait for virtual carrier */
2992 return tty_port_block_til_ready(port, tty, filp);
2993}
2994
2995static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2996{
2997 struct gsm_dlci *dlci = tty->driver_data;
2998
2999 if (dlci == NULL)
3000 return;
3001 if (dlci->state == DLCI_CLOSED)
3002 return;
3003 mutex_lock(&dlci->mutex);
3004 gsm_destroy_network(dlci);
3005 mutex_unlock(&dlci->mutex);
3006 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
3007 return;
3008 gsm_dlci_begin_close(dlci);
3009 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
3010 tty_port_lower_dtr_rts(&dlci->port);
3011 tty_port_close_end(&dlci->port, tty);
3012 tty_port_tty_set(&dlci->port, NULL);
3013 return;
3014}
3015
3016static void gsmtty_hangup(struct tty_struct *tty)
3017{
3018 struct gsm_dlci *dlci = tty->driver_data;
3019 if (dlci->state == DLCI_CLOSED)
3020 return;
3021 tty_port_hangup(&dlci->port);
3022 gsm_dlci_begin_close(dlci);
3023}
3024
3025static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3026 int len)
3027{
3028 int sent;
3029 struct gsm_dlci *dlci = tty->driver_data;
3030 if (dlci->state == DLCI_CLOSED)
3031 return -EINVAL;
3032 /* Stuff the bytes into the fifo queue */
3033 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
3034 /* Need to kick the channel */
3035 gsm_dlci_data_kick(dlci);
3036 return sent;
3037}
3038
3039static int gsmtty_write_room(struct tty_struct *tty)
3040{
3041 struct gsm_dlci *dlci = tty->driver_data;
3042 if (dlci->state == DLCI_CLOSED)
3043 return -EINVAL;
3044 return TX_SIZE - kfifo_len(dlci->fifo);
3045}
3046
3047static int gsmtty_chars_in_buffer(struct tty_struct *tty)
3048{
3049 struct gsm_dlci *dlci = tty->driver_data;
3050 if (dlci->state == DLCI_CLOSED)
3051 return -EINVAL;
3052 return kfifo_len(dlci->fifo);
3053}
3054
3055static void gsmtty_flush_buffer(struct tty_struct *tty)
3056{
3057 struct gsm_dlci *dlci = tty->driver_data;
3058 if (dlci->state == DLCI_CLOSED)
3059 return;
3060 /* Caution needed: If we implement reliable transport classes
3061 then the data being transmitted can't simply be junked once
3062 it has first hit the stack. Until then we can just blow it
3063 away */
3064 kfifo_reset(dlci->fifo);
3065 /* Need to unhook this DLCI from the transmit queue logic */
3066}
3067
3068static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3069{
3070 /* The FIFO handles the queue so the kernel will do the right
3071 thing waiting on chars_in_buffer before calling us. No work
3072 to do here */
3073}
3074
3075static int gsmtty_tiocmget(struct tty_struct *tty)
3076{
3077 struct gsm_dlci *dlci = tty->driver_data;
3078 if (dlci->state == DLCI_CLOSED)
3079 return -EINVAL;
3080 return dlci->modem_rx;
3081}
3082
3083static int gsmtty_tiocmset(struct tty_struct *tty,
3084 unsigned int set, unsigned int clear)
3085{
3086 struct gsm_dlci *dlci = tty->driver_data;
3087 unsigned int modem_tx = dlci->modem_tx;
3088
3089 if (dlci->state == DLCI_CLOSED)
3090 return -EINVAL;
3091 modem_tx &= ~clear;
3092 modem_tx |= set;
3093
3094 if (modem_tx != dlci->modem_tx) {
3095 dlci->modem_tx = modem_tx;
3096 return gsmtty_modem_update(dlci, 0);
3097 }
3098 return 0;
3099}
3100
3101
3102static int gsmtty_ioctl(struct tty_struct *tty,
3103 unsigned int cmd, unsigned long arg)
3104{
3105 struct gsm_dlci *dlci = tty->driver_data;
3106 struct gsm_netconfig nc;
3107 int index;
3108
3109 if (dlci->state == DLCI_CLOSED)
3110 return -EINVAL;
3111 switch (cmd) {
3112 case GSMIOC_ENABLE_NET:
3113 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3114 return -EFAULT;
3115 nc.if_name[IFNAMSIZ-1] = '\0';
3116 /* return net interface index or error code */
3117 mutex_lock(&dlci->mutex);
3118 index = gsm_create_network(dlci, &nc);
3119 mutex_unlock(&dlci->mutex);
3120 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3121 return -EFAULT;
3122 return index;
3123 case GSMIOC_DISABLE_NET:
3124 if (!capable(CAP_NET_ADMIN))
3125 return -EPERM;
3126 mutex_lock(&dlci->mutex);
3127 gsm_destroy_network(dlci);
3128 mutex_unlock(&dlci->mutex);
3129 return 0;
3130 default:
3131 return -ENOIOCTLCMD;
3132 }
3133}
3134
3135static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3136{
3137 struct gsm_dlci *dlci = tty->driver_data;
3138 if (dlci->state == DLCI_CLOSED)
3139 return;
3140 /* For the moment its fixed. In actual fact the speed information
3141 for the virtual channel can be propogated in both directions by
3142 the RPN control message. This however rapidly gets nasty as we
3143 then have to remap modem signals each way according to whether
3144 our virtual cable is null modem etc .. */
3145 tty_termios_copy_hw(&tty->termios, old);
3146}
3147
3148static void gsmtty_throttle(struct tty_struct *tty)
3149{
3150 struct gsm_dlci *dlci = tty->driver_data;
3151 if (dlci->state == DLCI_CLOSED)
3152 return;
3153 if (C_CRTSCTS(tty))
3154 dlci->modem_tx &= ~TIOCM_DTR;
3155 dlci->throttled = 1;
3156 /* Send an MSC with DTR cleared */
3157 gsmtty_modem_update(dlci, 0);
3158}
3159
3160static void gsmtty_unthrottle(struct tty_struct *tty)
3161{
3162 struct gsm_dlci *dlci = tty->driver_data;
3163 if (dlci->state == DLCI_CLOSED)
3164 return;
3165 if (C_CRTSCTS(tty))
3166 dlci->modem_tx |= TIOCM_DTR;
3167 dlci->throttled = 0;
3168 /* Send an MSC with DTR set */
3169 gsmtty_modem_update(dlci, 0);
3170}
3171
3172static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3173{
3174 struct gsm_dlci *dlci = tty->driver_data;
3175 int encode = 0; /* Off */
3176 if (dlci->state == DLCI_CLOSED)
3177 return -EINVAL;
3178
3179 if (state == -1) /* "On indefinitely" - we can't encode this
3180 properly */
3181 encode = 0x0F;
3182 else if (state > 0) {
3183 encode = state / 200; /* mS to encoding */
3184 if (encode > 0x0F)
3185 encode = 0x0F; /* Best effort */
3186 }
3187 return gsmtty_modem_update(dlci, encode);
3188}
3189
3190static void gsmtty_cleanup(struct tty_struct *tty)
3191{
3192 struct gsm_dlci *dlci = tty->driver_data;
3193 struct gsm_mux *gsm = dlci->gsm;
3194
3195 dlci_put(dlci);
3196 dlci_put(gsm->dlci[0]);
3197 mux_put(gsm);
3198}
3199
3200/* Virtual ttys for the demux */
3201static const struct tty_operations gsmtty_ops = {
3202 .install = gsmtty_install,
3203 .open = gsmtty_open,
3204 .close = gsmtty_close,
3205 .write = gsmtty_write,
3206 .write_room = gsmtty_write_room,
3207 .chars_in_buffer = gsmtty_chars_in_buffer,
3208 .flush_buffer = gsmtty_flush_buffer,
3209 .ioctl = gsmtty_ioctl,
3210 .throttle = gsmtty_throttle,
3211 .unthrottle = gsmtty_unthrottle,
3212 .set_termios = gsmtty_set_termios,
3213 .hangup = gsmtty_hangup,
3214 .wait_until_sent = gsmtty_wait_until_sent,
3215 .tiocmget = gsmtty_tiocmget,
3216 .tiocmset = gsmtty_tiocmset,
3217 .break_ctl = gsmtty_break_ctl,
3218 .cleanup = gsmtty_cleanup,
3219};
3220
3221
3222
3223static int __init gsm_init(void)
3224{
3225 /* Fill in our line protocol discipline, and register it */
3226 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3227 if (status != 0) {
3228 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3229 status);
3230 return status;
3231 }
3232
3233 gsm_tty_driver = alloc_tty_driver(256);
3234 if (!gsm_tty_driver) {
3235 tty_unregister_ldisc(N_GSM0710);
3236 pr_err("gsm_init: tty allocation failed.\n");
3237 return -EINVAL;
3238 }
3239 gsm_tty_driver->driver_name = "gsmtty";
3240 gsm_tty_driver->name = "gsmtty";
3241 gsm_tty_driver->major = 0; /* Dynamic */
3242 gsm_tty_driver->minor_start = 0;
3243 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3244 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3245 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3246 | TTY_DRIVER_HARDWARE_BREAK;
3247 gsm_tty_driver->init_termios = tty_std_termios;
3248 /* Fixme */
3249 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3250 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3251
3252 spin_lock_init(&gsm_mux_lock);
3253
3254 if (tty_register_driver(gsm_tty_driver)) {
3255 put_tty_driver(gsm_tty_driver);
3256 tty_unregister_ldisc(N_GSM0710);
3257 pr_err("gsm_init: tty registration failed.\n");
3258 return -EBUSY;
3259 }
3260 pr_debug("gsm_init: loaded as %d,%d.\n",
3261 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3262 return 0;
3263}
3264
3265static void __exit gsm_exit(void)
3266{
3267 int status = tty_unregister_ldisc(N_GSM0710);
3268 if (status != 0)
3269 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3270 status);
3271 tty_unregister_driver(gsm_tty_driver);
3272 put_tty_driver(gsm_tty_driver);
3273}
3274
3275module_init(gsm_init);
3276module_exit(gsm_exit);
3277
3278
3279MODULE_LICENSE("GPL");
3280MODULE_ALIAS_LDISC(N_GSM0710);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * n_gsm.c GSM 0710 tty multiplexor
4 * Copyright (c) 2009/10 Intel Corporation
5 * Copyright (c) 2022/23 Siemens Mobility GmbH
6 *
7 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
8 *
9 * Outgoing path:
10 * tty -> DLCI fifo -> scheduler -> GSM MUX data queue ---o-> ldisc
11 * control message -> GSM MUX control queue --´
12 *
13 * Incoming path:
14 * ldisc -> gsm_queue() -o--> tty
15 * `-> gsm_control_response()
16 *
17 * TO DO:
18 * Mostly done: ioctls for setting modes/timing
19 * Partly done: hooks so you can pull off frames to non tty devs
20 * Restart DLCI 0 when it closes ?
21 * Improve the tx engine
22 * Resolve tx side locking by adding a queue_head and routing
23 * all control traffic via it
24 * General tidy/document
25 * Review the locking/move to refcounts more (mux now moved to an
26 * alloc/free model ready)
27 * Use newest tty open/close port helpers and install hooks
28 * What to do about power functions ?
29 * Termios setting and negotiation
30 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
31 *
32 */
33
34#include <linux/types.h>
35#include <linux/major.h>
36#include <linux/errno.h>
37#include <linux/signal.h>
38#include <linux/fcntl.h>
39#include <linux/sched/signal.h>
40#include <linux/interrupt.h>
41#include <linux/tty.h>
42#include <linux/bitfield.h>
43#include <linux/ctype.h>
44#include <linux/mm.h>
45#include <linux/math.h>
46#include <linux/nospec.h>
47#include <linux/string.h>
48#include <linux/slab.h>
49#include <linux/poll.h>
50#include <linux/bitops.h>
51#include <linux/file.h>
52#include <linux/uaccess.h>
53#include <linux/module.h>
54#include <linux/timer.h>
55#include <linux/tty_flip.h>
56#include <linux/tty_driver.h>
57#include <linux/serial.h>
58#include <linux/kfifo.h>
59#include <linux/skbuff.h>
60#include <net/arp.h>
61#include <linux/ip.h>
62#include <linux/netdevice.h>
63#include <linux/etherdevice.h>
64#include <linux/gsmmux.h>
65#include "tty.h"
66
67static int debug;
68module_param(debug, int, 0600);
69
70/* Module debug bits */
71#define DBG_DUMP BIT(0) /* Data transmission dump. */
72#define DBG_CD_ON BIT(1) /* Always assume CD line on. */
73#define DBG_DATA BIT(2) /* Data transmission details. */
74#define DBG_ERRORS BIT(3) /* Details for fail conditions. */
75#define DBG_TTY BIT(4) /* Transmission statistics for DLCI TTYs. */
76#define DBG_PAYLOAD BIT(5) /* Limits DBG_DUMP to payload frames. */
77
78/* Defaults: these are from the specification */
79
80#define T1 10 /* 100mS */
81#define T2 34 /* 333mS */
82#define T3 10 /* 10s */
83#define N2 3 /* Retry 3 times */
84#define K 2 /* outstanding I frames */
85
86#define MAX_T3 255 /* In seconds. */
87#define MAX_WINDOW_SIZE 7 /* Limit of K in error recovery mode. */
88
89/* Use long timers for testing at low speed with debug on */
90#ifdef DEBUG_TIMING
91#define T1 100
92#define T2 200
93#endif
94
95/*
96 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
97 * limits so this is plenty
98 */
99#define MAX_MRU 1500
100#define MAX_MTU 1500
101#define MIN_MTU (PROT_OVERHEAD + 1)
102/* SOF, ADDR, CTRL, LEN1, LEN2, ..., FCS, EOF */
103#define PROT_OVERHEAD 7
104#define GSM_NET_TX_TIMEOUT (HZ*10)
105
106/*
107 * struct gsm_mux_net - network interface
108 *
109 * Created when net interface is initialized.
110 */
111struct gsm_mux_net {
112 struct kref ref;
113 struct gsm_dlci *dlci;
114};
115
116/*
117 * Each block of data we have queued to go out is in the form of
118 * a gsm_msg which holds everything we need in a link layer independent
119 * format
120 */
121
122struct gsm_msg {
123 struct list_head list;
124 u8 addr; /* DLCI address + flags */
125 u8 ctrl; /* Control byte + flags */
126 unsigned int len; /* Length of data block (can be zero) */
127 u8 *data; /* Points into buffer but not at the start */
128 u8 buffer[];
129};
130
131enum gsm_dlci_state {
132 DLCI_CLOSED,
133 DLCI_WAITING_CONFIG, /* Waiting for DLCI configuration from user */
134 DLCI_CONFIGURE, /* Sending PN (for adaption > 1) */
135 DLCI_OPENING, /* Sending SABM not seen UA */
136 DLCI_OPEN, /* SABM/UA complete */
137 DLCI_CLOSING, /* Sending DISC not seen UA/DM */
138};
139
140enum gsm_dlci_mode {
141 DLCI_MODE_ABM, /* Normal Asynchronous Balanced Mode */
142 DLCI_MODE_ADM, /* Asynchronous Disconnected Mode */
143};
144
145/*
146 * Each active data link has a gsm_dlci structure associated which ties
147 * the link layer to an optional tty (if the tty side is open). To avoid
148 * complexity right now these are only ever freed up when the mux is
149 * shut down.
150 *
151 * At the moment we don't free DLCI objects until the mux is torn down
152 * this avoid object life time issues but might be worth review later.
153 */
154
155struct gsm_dlci {
156 struct gsm_mux *gsm;
157 int addr;
158 enum gsm_dlci_state state;
159 struct mutex mutex;
160
161 /* Link layer */
162 enum gsm_dlci_mode mode;
163 spinlock_t lock; /* Protects the internal state */
164 struct timer_list t1; /* Retransmit timer for SABM and UA */
165 int retries;
166 /* Uplink tty if active */
167 struct tty_port port; /* The tty bound to this DLCI if there is one */
168#define TX_SIZE 4096 /* Must be power of 2. */
169 struct kfifo fifo; /* Queue fifo for the DLCI */
170 int adaption; /* Adaption layer in use */
171 int prev_adaption;
172 u32 modem_rx; /* Our incoming virtual modem lines */
173 u32 modem_tx; /* Our outgoing modem lines */
174 unsigned int mtu;
175 bool dead; /* Refuse re-open */
176 /* Configuration */
177 u8 prio; /* Priority */
178 u8 ftype; /* Frame type */
179 u8 k; /* Window size */
180 /* Flow control */
181 bool throttled; /* Private copy of throttle state */
182 bool constipated; /* Throttle status for outgoing */
183 /* Packetised I/O */
184 struct sk_buff *skb; /* Frame being sent */
185 struct sk_buff_head skb_list; /* Queued frames */
186 /* Data handling callback */
187 void (*data)(struct gsm_dlci *dlci, const u8 *data, int len);
188 void (*prev_data)(struct gsm_dlci *dlci, const u8 *data, int len);
189 struct net_device *net; /* network interface, if created */
190};
191
192/*
193 * Parameter bits used for parameter negotiation according to 3GPP 27.010
194 * chapter 5.4.6.3.1.
195 */
196
197struct gsm_dlci_param_bits {
198 u8 d_bits;
199 u8 i_cl_bits;
200 u8 p_bits;
201 u8 t_bits;
202 __le16 n_bits;
203 u8 na_bits;
204 u8 k_bits;
205};
206
207static_assert(sizeof(struct gsm_dlci_param_bits) == 8);
208
209#define PN_D_FIELD_DLCI GENMASK(5, 0)
210#define PN_I_CL_FIELD_FTYPE GENMASK(3, 0)
211#define PN_I_CL_FIELD_ADAPTION GENMASK(7, 4)
212#define PN_P_FIELD_PRIO GENMASK(5, 0)
213#define PN_T_FIELD_T1 GENMASK(7, 0)
214#define PN_N_FIELD_N1 GENMASK(15, 0)
215#define PN_NA_FIELD_N2 GENMASK(7, 0)
216#define PN_K_FIELD_K GENMASK(2, 0)
217
218/* Total number of supported devices */
219#define GSM_TTY_MINORS 256
220
221/* DLCI 0, 62/63 are special or reserved see gsmtty_open */
222
223#define NUM_DLCI 64
224
225/*
226 * DLCI 0 is used to pass control blocks out of band of the data
227 * flow (and with a higher link priority). One command can be outstanding
228 * at a time and we use this structure to manage them. They are created
229 * and destroyed by the user context, and updated by the receive paths
230 * and timers
231 */
232
233struct gsm_control {
234 u8 cmd; /* Command we are issuing */
235 u8 *data; /* Data for the command in case we retransmit */
236 int len; /* Length of block for retransmission */
237 int done; /* Done flag */
238 int error; /* Error if any */
239};
240
241enum gsm_encoding {
242 GSM_BASIC_OPT,
243 GSM_ADV_OPT,
244};
245
246enum gsm_mux_state {
247 GSM_SEARCH,
248 GSM0_ADDRESS,
249 GSM0_CONTROL,
250 GSM0_LEN0,
251 GSM0_LEN1,
252 GSM0_DATA,
253 GSM0_FCS,
254 GSM0_SSOF,
255 GSM1_START,
256 GSM1_ADDRESS,
257 GSM1_CONTROL,
258 GSM1_DATA,
259 GSM1_OVERRUN,
260};
261
262/*
263 * Each GSM mux we have is represented by this structure. If we are
264 * operating as an ldisc then we use this structure as our ldisc
265 * state. We need to sort out lifetimes and locking with respect
266 * to the gsm mux array. For now we don't free DLCI objects that
267 * have been instantiated until the mux itself is terminated.
268 *
269 * To consider further: tty open versus mux shutdown.
270 */
271
272struct gsm_mux {
273 struct tty_struct *tty; /* The tty our ldisc is bound to */
274 spinlock_t lock;
275 struct mutex mutex;
276 unsigned int num;
277 struct kref ref;
278
279 /* Events on the GSM channel */
280 wait_queue_head_t event;
281
282 /* ldisc send work */
283 struct work_struct tx_work;
284
285 /* Bits for GSM mode decoding */
286
287 /* Framing Layer */
288 u8 *buf;
289 enum gsm_mux_state state;
290 unsigned int len;
291 unsigned int address;
292 unsigned int count;
293 bool escape;
294 enum gsm_encoding encoding;
295 u8 control;
296 u8 fcs;
297 u8 *txframe; /* TX framing buffer */
298
299 /* Method for the receiver side */
300 void (*receive)(struct gsm_mux *gsm, u8 ch);
301
302 /* Link Layer */
303 unsigned int mru;
304 unsigned int mtu;
305 int initiator; /* Did we initiate connection */
306 bool dead; /* Has the mux been shut down */
307 struct gsm_dlci *dlci[NUM_DLCI];
308 int old_c_iflag; /* termios c_iflag value before attach */
309 bool constipated; /* Asked by remote to shut up */
310 bool has_devices; /* Devices were registered */
311
312 spinlock_t tx_lock;
313 unsigned int tx_bytes; /* TX data outstanding */
314#define TX_THRESH_HI 8192
315#define TX_THRESH_LO 2048
316 struct list_head tx_ctrl_list; /* Pending control packets */
317 struct list_head tx_data_list; /* Pending data packets */
318
319 /* Control messages */
320 struct timer_list kick_timer; /* Kick TX queuing on timeout */
321 struct timer_list t2_timer; /* Retransmit timer for commands */
322 int cretries; /* Command retry counter */
323 struct gsm_control *pending_cmd;/* Our current pending command */
324 spinlock_t control_lock; /* Protects the pending command */
325
326 /* Keep-alive */
327 struct timer_list ka_timer; /* Keep-alive response timer */
328 u8 ka_num; /* Keep-alive match pattern */
329 signed int ka_retries; /* Keep-alive retry counter, -1 if not yet initialized */
330
331 /* Configuration */
332 int adaption; /* 1 or 2 supported */
333 u8 ftype; /* UI or UIH */
334 int t1, t2; /* Timers in 1/100th of a sec */
335 unsigned int t3; /* Power wake-up timer in seconds. */
336 int n2; /* Retry count */
337 u8 k; /* Window size */
338 bool wait_config; /* Wait for configuration by ioctl before DLCI open */
339 u32 keep_alive; /* Control channel keep-alive in 10ms */
340
341 /* Statistics (not currently exposed) */
342 unsigned long bad_fcs;
343 unsigned long malformed;
344 unsigned long io_error;
345 unsigned long open_error;
346 unsigned long bad_size;
347 unsigned long unsupported;
348};
349
350
351/*
352 * Mux objects - needed so that we can translate a tty index into the
353 * relevant mux and DLCI.
354 */
355
356#define MAX_MUX 4 /* 256 minors */
357static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
358static DEFINE_SPINLOCK(gsm_mux_lock);
359
360static struct tty_driver *gsm_tty_driver;
361
362/*
363 * This section of the driver logic implements the GSM encodings
364 * both the basic and the 'advanced'. Reliable transport is not
365 * supported.
366 */
367
368#define CR 0x02
369#define EA 0x01
370#define PF 0x10
371
372/* I is special: the rest are ..*/
373#define RR 0x01
374#define UI 0x03
375#define RNR 0x05
376#define REJ 0x09
377#define DM 0x0F
378#define SABM 0x2F
379#define DISC 0x43
380#define UA 0x63
381#define UIH 0xEF
382
383/* Channel commands */
384#define CMD_NSC 0x09
385#define CMD_TEST 0x11
386#define CMD_PSC 0x21
387#define CMD_RLS 0x29
388#define CMD_FCOFF 0x31
389#define CMD_PN 0x41
390#define CMD_RPN 0x49
391#define CMD_FCON 0x51
392#define CMD_CLD 0x61
393#define CMD_SNC 0x69
394#define CMD_MSC 0x71
395
396/* Virtual modem bits */
397#define MDM_FC 0x01
398#define MDM_RTC 0x02
399#define MDM_RTR 0x04
400#define MDM_IC 0x20
401#define MDM_DV 0x40
402
403#define GSM0_SOF 0xF9
404#define GSM1_SOF 0x7E
405#define GSM1_ESCAPE 0x7D
406#define GSM1_ESCAPE_BITS 0x20
407#define XON 0x11
408#define XOFF 0x13
409#define ISO_IEC_646_MASK 0x7F
410
411static const struct tty_port_operations gsm_port_ops;
412
413/*
414 * CRC table for GSM 0710
415 */
416
417static const u8 gsm_fcs8[256] = {
418 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
419 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
420 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
421 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
422 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
423 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
424 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
425 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
426 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
427 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
428 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
429 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
430 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
431 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
432 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
433 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
434 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
435 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
436 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
437 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
438 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
439 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
440 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
441 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
442 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
443 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
444 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
445 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
446 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
447 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
448 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
449 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
450};
451
452#define INIT_FCS 0xFF
453#define GOOD_FCS 0xCF
454
455static void gsm_dlci_close(struct gsm_dlci *dlci);
456static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len);
457static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk);
458static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
459 u8 ctrl);
460static int gsm_send_packet(struct gsm_mux *gsm, struct gsm_msg *msg);
461static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr);
462static void gsmld_write_trigger(struct gsm_mux *gsm);
463static void gsmld_write_task(struct work_struct *work);
464
465/**
466 * gsm_fcs_add - update FCS
467 * @fcs: Current FCS
468 * @c: Next data
469 *
470 * Update the FCS to include c. Uses the algorithm in the specification
471 * notes.
472 */
473
474static inline u8 gsm_fcs_add(u8 fcs, u8 c)
475{
476 return gsm_fcs8[fcs ^ c];
477}
478
479/**
480 * gsm_fcs_add_block - update FCS for a block
481 * @fcs: Current FCS
482 * @c: buffer of data
483 * @len: length of buffer
484 *
485 * Update the FCS to include c. Uses the algorithm in the specification
486 * notes.
487 */
488
489static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
490{
491 while (len--)
492 fcs = gsm_fcs8[fcs ^ *c++];
493 return fcs;
494}
495
496/**
497 * gsm_read_ea - read a byte into an EA
498 * @val: variable holding value
499 * @c: byte going into the EA
500 *
501 * Processes one byte of an EA. Updates the passed variable
502 * and returns 1 if the EA is now completely read
503 */
504
505static int gsm_read_ea(unsigned int *val, u8 c)
506{
507 /* Add the next 7 bits into the value */
508 *val <<= 7;
509 *val |= c >> 1;
510 /* Was this the last byte of the EA 1 = yes*/
511 return c & EA;
512}
513
514/**
515 * gsm_read_ea_val - read a value until EA
516 * @val: variable holding value
517 * @data: buffer of data
518 * @dlen: length of data
519 *
520 * Processes an EA value. Updates the passed variable and
521 * returns the processed data length.
522 */
523static unsigned int gsm_read_ea_val(unsigned int *val, const u8 *data, int dlen)
524{
525 unsigned int len = 0;
526
527 for (; dlen > 0; dlen--) {
528 len++;
529 if (gsm_read_ea(val, *data++))
530 break;
531 }
532 return len;
533}
534
535/**
536 * gsm_encode_modem - encode modem data bits
537 * @dlci: DLCI to encode from
538 *
539 * Returns the correct GSM encoded modem status bits (6 bit field) for
540 * the current status of the DLCI and attached tty object
541 */
542
543static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
544{
545 u8 modembits = 0;
546 /* FC is true flow control not modem bits */
547 if (dlci->throttled)
548 modembits |= MDM_FC;
549 if (dlci->modem_tx & TIOCM_DTR)
550 modembits |= MDM_RTC;
551 if (dlci->modem_tx & TIOCM_RTS)
552 modembits |= MDM_RTR;
553 if (dlci->modem_tx & TIOCM_RI)
554 modembits |= MDM_IC;
555 if (dlci->modem_tx & TIOCM_CD || dlci->gsm->initiator)
556 modembits |= MDM_DV;
557 /* special mappings for passive side to operate as UE */
558 if (dlci->modem_tx & TIOCM_OUT1)
559 modembits |= MDM_IC;
560 if (dlci->modem_tx & TIOCM_OUT2)
561 modembits |= MDM_DV;
562 return modembits;
563}
564
565static void gsm_hex_dump_bytes(const char *fname, const u8 *data,
566 unsigned long len)
567{
568 char *prefix;
569
570 if (!fname) {
571 print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, 16, 1, data, len,
572 true);
573 return;
574 }
575
576 prefix = kasprintf(GFP_ATOMIC, "%s: ", fname);
577 if (!prefix)
578 return;
579 print_hex_dump(KERN_INFO, prefix, DUMP_PREFIX_OFFSET, 16, 1, data, len,
580 true);
581 kfree(prefix);
582}
583
584/**
585 * gsm_encode_params - encode DLCI parameters
586 * @dlci: DLCI to encode from
587 * @params: buffer to fill with the encoded parameters
588 *
589 * Encodes the parameters according to GSM 07.10 section 5.4.6.3.1
590 * table 3.
591 */
592static int gsm_encode_params(const struct gsm_dlci *dlci,
593 struct gsm_dlci_param_bits *params)
594{
595 const struct gsm_mux *gsm = dlci->gsm;
596 unsigned int i, cl;
597
598 switch (dlci->ftype) {
599 case UIH:
600 i = 0; /* UIH */
601 break;
602 case UI:
603 i = 1; /* UI */
604 break;
605 default:
606 pr_debug("unsupported frame type %d\n", dlci->ftype);
607 return -EINVAL;
608 }
609
610 switch (dlci->adaption) {
611 case 1: /* Unstructured */
612 cl = 0; /* convergence layer type 1 */
613 break;
614 case 2: /* Unstructured with modem bits. */
615 cl = 1; /* convergence layer type 2 */
616 break;
617 default:
618 pr_debug("unsupported adaption %d\n", dlci->adaption);
619 return -EINVAL;
620 }
621
622 params->d_bits = FIELD_PREP(PN_D_FIELD_DLCI, dlci->addr);
623 /* UIH, convergence layer type 1 */
624 params->i_cl_bits = FIELD_PREP(PN_I_CL_FIELD_FTYPE, i) |
625 FIELD_PREP(PN_I_CL_FIELD_ADAPTION, cl);
626 params->p_bits = FIELD_PREP(PN_P_FIELD_PRIO, dlci->prio);
627 params->t_bits = FIELD_PREP(PN_T_FIELD_T1, gsm->t1);
628 params->n_bits = cpu_to_le16(FIELD_PREP(PN_N_FIELD_N1, dlci->mtu));
629 params->na_bits = FIELD_PREP(PN_NA_FIELD_N2, gsm->n2);
630 params->k_bits = FIELD_PREP(PN_K_FIELD_K, dlci->k);
631
632 return 0;
633}
634
635/**
636 * gsm_register_devices - register all tty devices for a given mux index
637 *
638 * @driver: the tty driver that describes the tty devices
639 * @index: the mux number is used to calculate the minor numbers of the
640 * ttys for this mux and may differ from the position in the
641 * mux array.
642 */
643static int gsm_register_devices(struct tty_driver *driver, unsigned int index)
644{
645 struct device *dev;
646 int i;
647 unsigned int base;
648
649 if (!driver || index >= MAX_MUX)
650 return -EINVAL;
651
652 base = index * NUM_DLCI; /* first minor for this index */
653 for (i = 1; i < NUM_DLCI; i++) {
654 /* Don't register device 0 - this is the control channel
655 * and not a usable tty interface
656 */
657 dev = tty_register_device(gsm_tty_driver, base + i, NULL);
658 if (IS_ERR(dev)) {
659 if (debug & DBG_ERRORS)
660 pr_info("%s failed to register device minor %u",
661 __func__, base + i);
662 for (i--; i >= 1; i--)
663 tty_unregister_device(gsm_tty_driver, base + i);
664 return PTR_ERR(dev);
665 }
666 }
667
668 return 0;
669}
670
671/**
672 * gsm_unregister_devices - unregister all tty devices for a given mux index
673 *
674 * @driver: the tty driver that describes the tty devices
675 * @index: the mux number is used to calculate the minor numbers of the
676 * ttys for this mux and may differ from the position in the
677 * mux array.
678 */
679static void gsm_unregister_devices(struct tty_driver *driver,
680 unsigned int index)
681{
682 int i;
683 unsigned int base;
684
685 if (!driver || index >= MAX_MUX)
686 return;
687
688 base = index * NUM_DLCI; /* first minor for this index */
689 for (i = 1; i < NUM_DLCI; i++) {
690 /* Don't unregister device 0 - this is the control
691 * channel and not a usable tty interface
692 */
693 tty_unregister_device(gsm_tty_driver, base + i);
694 }
695}
696
697/**
698 * gsm_print_packet - display a frame for debug
699 * @hdr: header to print before decode
700 * @addr: address EA from the frame
701 * @cr: C/R bit seen as initiator
702 * @control: control including PF bit
703 * @data: following data bytes
704 * @dlen: length of data
705 *
706 * Displays a packet in human readable format for debugging purposes. The
707 * style is based on amateur radio LAP-B dump display.
708 */
709
710static void gsm_print_packet(const char *hdr, int addr, int cr,
711 u8 control, const u8 *data, int dlen)
712{
713 if (!(debug & DBG_DUMP))
714 return;
715 /* Only show user payload frames if debug & DBG_PAYLOAD */
716 if (!(debug & DBG_PAYLOAD) && addr != 0)
717 if ((control & ~PF) == UI || (control & ~PF) == UIH)
718 return;
719
720 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
721
722 switch (control & ~PF) {
723 case SABM:
724 pr_cont("SABM");
725 break;
726 case UA:
727 pr_cont("UA");
728 break;
729 case DISC:
730 pr_cont("DISC");
731 break;
732 case DM:
733 pr_cont("DM");
734 break;
735 case UI:
736 pr_cont("UI");
737 break;
738 case UIH:
739 pr_cont("UIH");
740 break;
741 default:
742 if (!(control & 0x01)) {
743 pr_cont("I N(S)%d N(R)%d",
744 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
745 } else switch (control & 0x0F) {
746 case RR:
747 pr_cont("RR(%d)", (control & 0xE0) >> 5);
748 break;
749 case RNR:
750 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
751 break;
752 case REJ:
753 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
754 break;
755 default:
756 pr_cont("[%02X]", control);
757 }
758 }
759
760 if (control & PF)
761 pr_cont("(P)");
762 else
763 pr_cont("(F)");
764
765 gsm_hex_dump_bytes(NULL, data, dlen);
766}
767
768
769/*
770 * Link level transmission side
771 */
772
773/**
774 * gsm_stuff_frame - bytestuff a packet
775 * @input: input buffer
776 * @output: output buffer
777 * @len: length of input
778 *
779 * Expand a buffer by bytestuffing it. The worst case size change
780 * is doubling and the caller is responsible for handing out
781 * suitable sized buffers.
782 */
783
784static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
785{
786 int olen = 0;
787 while (len--) {
788 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
789 || (*input & ISO_IEC_646_MASK) == XON
790 || (*input & ISO_IEC_646_MASK) == XOFF) {
791 *output++ = GSM1_ESCAPE;
792 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
793 olen++;
794 } else
795 *output++ = *input++;
796 olen++;
797 }
798 return olen;
799}
800
801/**
802 * gsm_send - send a control frame
803 * @gsm: our GSM mux
804 * @addr: address for control frame
805 * @cr: command/response bit seen as initiator
806 * @control: control byte including PF bit
807 *
808 * Format up and transmit a control frame. These should be transmitted
809 * ahead of data when they are needed.
810 */
811static int gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
812{
813 struct gsm_msg *msg;
814 u8 *dp;
815 int ocr;
816 unsigned long flags;
817
818 msg = gsm_data_alloc(gsm, addr, 0, control);
819 if (!msg)
820 return -ENOMEM;
821
822 /* toggle C/R coding if not initiator */
823 ocr = cr ^ (gsm->initiator ? 0 : 1);
824
825 msg->data -= 3;
826 dp = msg->data;
827 *dp++ = (addr << 2) | (ocr << 1) | EA;
828 *dp++ = control;
829
830 if (gsm->encoding == GSM_BASIC_OPT)
831 *dp++ = EA; /* Length of data = 0 */
832
833 *dp = 0xFF - gsm_fcs_add_block(INIT_FCS, msg->data, dp - msg->data);
834 msg->len = (dp - msg->data) + 1;
835
836 gsm_print_packet("Q->", addr, cr, control, NULL, 0);
837
838 spin_lock_irqsave(&gsm->tx_lock, flags);
839 list_add_tail(&msg->list, &gsm->tx_ctrl_list);
840 gsm->tx_bytes += msg->len;
841 spin_unlock_irqrestore(&gsm->tx_lock, flags);
842 gsmld_write_trigger(gsm);
843
844 return 0;
845}
846
847/**
848 * gsm_dlci_clear_queues - remove outstanding data for a DLCI
849 * @gsm: mux
850 * @dlci: clear for this DLCI
851 *
852 * Clears the data queues for a given DLCI.
853 */
854static void gsm_dlci_clear_queues(struct gsm_mux *gsm, struct gsm_dlci *dlci)
855{
856 struct gsm_msg *msg, *nmsg;
857 int addr = dlci->addr;
858 unsigned long flags;
859
860 /* Clear DLCI write fifo first */
861 spin_lock_irqsave(&dlci->lock, flags);
862 kfifo_reset(&dlci->fifo);
863 spin_unlock_irqrestore(&dlci->lock, flags);
864
865 /* Clear data packets in MUX write queue */
866 spin_lock_irqsave(&gsm->tx_lock, flags);
867 list_for_each_entry_safe(msg, nmsg, &gsm->tx_data_list, list) {
868 if (msg->addr != addr)
869 continue;
870 gsm->tx_bytes -= msg->len;
871 list_del(&msg->list);
872 kfree(msg);
873 }
874 spin_unlock_irqrestore(&gsm->tx_lock, flags);
875}
876
877/**
878 * gsm_response - send a control response
879 * @gsm: our GSM mux
880 * @addr: address for control frame
881 * @control: control byte including PF bit
882 *
883 * Format up and transmit a link level response frame.
884 */
885
886static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
887{
888 gsm_send(gsm, addr, 0, control);
889}
890
891/**
892 * gsm_command - send a control command
893 * @gsm: our GSM mux
894 * @addr: address for control frame
895 * @control: control byte including PF bit
896 *
897 * Format up and transmit a link level command frame.
898 */
899
900static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
901{
902 gsm_send(gsm, addr, 1, control);
903}
904
905/* Data transmission */
906
907#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
908
909/**
910 * gsm_data_alloc - allocate data frame
911 * @gsm: GSM mux
912 * @addr: DLCI address
913 * @len: length excluding header and FCS
914 * @ctrl: control byte
915 *
916 * Allocate a new data buffer for sending frames with data. Space is left
917 * at the front for header bytes but that is treated as an implementation
918 * detail and not for the high level code to use
919 */
920
921static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
922 u8 ctrl)
923{
924 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
925 GFP_ATOMIC);
926 if (m == NULL)
927 return NULL;
928 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
929 m->len = len;
930 m->addr = addr;
931 m->ctrl = ctrl;
932 INIT_LIST_HEAD(&m->list);
933 return m;
934}
935
936/**
937 * gsm_send_packet - sends a single packet
938 * @gsm: GSM Mux
939 * @msg: packet to send
940 *
941 * The given packet is encoded and sent out. No memory is freed.
942 * The caller must hold the gsm tx lock.
943 */
944static int gsm_send_packet(struct gsm_mux *gsm, struct gsm_msg *msg)
945{
946 int len, ret;
947
948
949 if (gsm->encoding == GSM_BASIC_OPT) {
950 gsm->txframe[0] = GSM0_SOF;
951 memcpy(gsm->txframe + 1, msg->data, msg->len);
952 gsm->txframe[msg->len + 1] = GSM0_SOF;
953 len = msg->len + 2;
954 } else {
955 gsm->txframe[0] = GSM1_SOF;
956 len = gsm_stuff_frame(msg->data, gsm->txframe + 1, msg->len);
957 gsm->txframe[len + 1] = GSM1_SOF;
958 len += 2;
959 }
960
961 if (debug & DBG_DATA)
962 gsm_hex_dump_bytes(__func__, gsm->txframe, len);
963 gsm_print_packet("-->", msg->addr, gsm->initiator, msg->ctrl, msg->data,
964 msg->len);
965
966 ret = gsmld_output(gsm, gsm->txframe, len);
967 if (ret <= 0)
968 return ret;
969 /* FIXME: Can eliminate one SOF in many more cases */
970 gsm->tx_bytes -= msg->len;
971
972 return 0;
973}
974
975/**
976 * gsm_is_flow_ctrl_msg - checks if flow control message
977 * @msg: message to check
978 *
979 * Returns true if the given message is a flow control command of the
980 * control channel. False is returned in any other case.
981 */
982static bool gsm_is_flow_ctrl_msg(struct gsm_msg *msg)
983{
984 unsigned int cmd;
985
986 if (msg->addr > 0)
987 return false;
988
989 switch (msg->ctrl & ~PF) {
990 case UI:
991 case UIH:
992 cmd = 0;
993 if (gsm_read_ea_val(&cmd, msg->data + 2, msg->len - 2) < 1)
994 break;
995 switch (cmd & ~PF) {
996 case CMD_FCOFF:
997 case CMD_FCON:
998 return true;
999 }
1000 break;
1001 }
1002
1003 return false;
1004}
1005
1006/**
1007 * gsm_data_kick - poke the queue
1008 * @gsm: GSM Mux
1009 *
1010 * The tty device has called us to indicate that room has appeared in
1011 * the transmit queue. Ram more data into the pipe if we have any.
1012 * If we have been flow-stopped by a CMD_FCOFF, then we can only
1013 * send messages on DLCI0 until CMD_FCON. The caller must hold
1014 * the gsm tx lock.
1015 */
1016static int gsm_data_kick(struct gsm_mux *gsm)
1017{
1018 struct gsm_msg *msg, *nmsg;
1019 struct gsm_dlci *dlci;
1020 int ret;
1021
1022 clear_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
1023
1024 /* Serialize control messages and control channel messages first */
1025 list_for_each_entry_safe(msg, nmsg, &gsm->tx_ctrl_list, list) {
1026 if (gsm->constipated && !gsm_is_flow_ctrl_msg(msg))
1027 continue;
1028 ret = gsm_send_packet(gsm, msg);
1029 switch (ret) {
1030 case -ENOSPC:
1031 return -ENOSPC;
1032 case -ENODEV:
1033 /* ldisc not open */
1034 gsm->tx_bytes -= msg->len;
1035 list_del(&msg->list);
1036 kfree(msg);
1037 continue;
1038 default:
1039 if (ret >= 0) {
1040 list_del(&msg->list);
1041 kfree(msg);
1042 }
1043 break;
1044 }
1045 }
1046
1047 if (gsm->constipated)
1048 return -EAGAIN;
1049
1050 /* Serialize other channels */
1051 if (list_empty(&gsm->tx_data_list))
1052 return 0;
1053 list_for_each_entry_safe(msg, nmsg, &gsm->tx_data_list, list) {
1054 dlci = gsm->dlci[msg->addr];
1055 /* Send only messages for DLCIs with valid state */
1056 if (dlci->state != DLCI_OPEN) {
1057 gsm->tx_bytes -= msg->len;
1058 list_del(&msg->list);
1059 kfree(msg);
1060 continue;
1061 }
1062 ret = gsm_send_packet(gsm, msg);
1063 switch (ret) {
1064 case -ENOSPC:
1065 return -ENOSPC;
1066 case -ENODEV:
1067 /* ldisc not open */
1068 gsm->tx_bytes -= msg->len;
1069 list_del(&msg->list);
1070 kfree(msg);
1071 continue;
1072 default:
1073 if (ret >= 0) {
1074 list_del(&msg->list);
1075 kfree(msg);
1076 }
1077 break;
1078 }
1079 }
1080
1081 return 1;
1082}
1083
1084/**
1085 * __gsm_data_queue - queue a UI or UIH frame
1086 * @dlci: DLCI sending the data
1087 * @msg: message queued
1088 *
1089 * Add data to the transmit queue and try and get stuff moving
1090 * out of the mux tty if not already doing so. The Caller must hold
1091 * the gsm tx lock.
1092 */
1093
1094static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
1095{
1096 struct gsm_mux *gsm = dlci->gsm;
1097 u8 *dp = msg->data;
1098 u8 *fcs = dp + msg->len;
1099
1100 /* Fill in the header */
1101 if (gsm->encoding == GSM_BASIC_OPT) {
1102 if (msg->len < 128)
1103 *--dp = (msg->len << 1) | EA;
1104 else {
1105 *--dp = (msg->len >> 7); /* bits 7 - 15 */
1106 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
1107 }
1108 }
1109
1110 *--dp = msg->ctrl;
1111 if (gsm->initiator)
1112 *--dp = (msg->addr << 2) | CR | EA;
1113 else
1114 *--dp = (msg->addr << 2) | EA;
1115 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
1116 /* Ugly protocol layering violation */
1117 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
1118 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
1119 *fcs = 0xFF - *fcs;
1120
1121 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
1122 msg->data, msg->len);
1123
1124 /* Move the header back and adjust the length, also allow for the FCS
1125 now tacked on the end */
1126 msg->len += (msg->data - dp) + 1;
1127 msg->data = dp;
1128
1129 /* Add to the actual output queue */
1130 switch (msg->ctrl & ~PF) {
1131 case UI:
1132 case UIH:
1133 if (msg->addr > 0) {
1134 list_add_tail(&msg->list, &gsm->tx_data_list);
1135 break;
1136 }
1137 fallthrough;
1138 default:
1139 list_add_tail(&msg->list, &gsm->tx_ctrl_list);
1140 break;
1141 }
1142 gsm->tx_bytes += msg->len;
1143
1144 gsmld_write_trigger(gsm);
1145 mod_timer(&gsm->kick_timer, jiffies + 10 * gsm->t1 * HZ / 100);
1146}
1147
1148/**
1149 * gsm_data_queue - queue a UI or UIH frame
1150 * @dlci: DLCI sending the data
1151 * @msg: message queued
1152 *
1153 * Add data to the transmit queue and try and get stuff moving
1154 * out of the mux tty if not already doing so. Take the
1155 * the gsm tx lock and dlci lock.
1156 */
1157
1158static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
1159{
1160 unsigned long flags;
1161 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
1162 __gsm_data_queue(dlci, msg);
1163 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
1164}
1165
1166/**
1167 * gsm_dlci_data_output - try and push data out of a DLCI
1168 * @gsm: mux
1169 * @dlci: the DLCI to pull data from
1170 *
1171 * Pull data from a DLCI and send it into the transmit queue if there
1172 * is data. Keep to the MRU of the mux. This path handles the usual tty
1173 * interface which is a byte stream with optional modem data.
1174 *
1175 * Caller must hold the tx_lock of the mux.
1176 */
1177
1178static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
1179{
1180 struct gsm_msg *msg;
1181 u8 *dp;
1182 int h, len, size;
1183
1184 /* for modem bits without break data */
1185 h = ((dlci->adaption == 1) ? 0 : 1);
1186
1187 len = kfifo_len(&dlci->fifo);
1188 if (len == 0)
1189 return 0;
1190
1191 /* MTU/MRU count only the data bits but watch adaption mode */
1192 if ((len + h) > dlci->mtu)
1193 len = dlci->mtu - h;
1194
1195 size = len + h;
1196
1197 msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype);
1198 if (!msg)
1199 return -ENOMEM;
1200 dp = msg->data;
1201 switch (dlci->adaption) {
1202 case 1: /* Unstructured */
1203 break;
1204 case 2: /* Unstructured with modem bits.
1205 * Always one byte as we never send inline break data
1206 */
1207 *dp++ = (gsm_encode_modem(dlci) << 1) | EA;
1208 break;
1209 default:
1210 pr_err("%s: unsupported adaption %d\n", __func__,
1211 dlci->adaption);
1212 break;
1213 }
1214
1215 WARN_ON(len != kfifo_out_locked(&dlci->fifo, dp, len,
1216 &dlci->lock));
1217
1218 /* Notify upper layer about available send space. */
1219 tty_port_tty_wakeup(&dlci->port);
1220
1221 __gsm_data_queue(dlci, msg);
1222 /* Bytes of data we used up */
1223 return size;
1224}
1225
1226/**
1227 * gsm_dlci_data_output_framed - try and push data out of a DLCI
1228 * @gsm: mux
1229 * @dlci: the DLCI to pull data from
1230 *
1231 * Pull data from a DLCI and send it into the transmit queue if there
1232 * is data. Keep to the MRU of the mux. This path handles framed data
1233 * queued as skbuffs to the DLCI.
1234 *
1235 * Caller must hold the tx_lock of the mux.
1236 */
1237
1238static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
1239 struct gsm_dlci *dlci)
1240{
1241 struct gsm_msg *msg;
1242 u8 *dp;
1243 int len, size;
1244 int last = 0, first = 0;
1245 int overhead = 0;
1246
1247 /* One byte per frame is used for B/F flags */
1248 if (dlci->adaption == 4)
1249 overhead = 1;
1250
1251 /* dlci->skb is locked by tx_lock */
1252 if (dlci->skb == NULL) {
1253 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
1254 if (dlci->skb == NULL)
1255 return 0;
1256 first = 1;
1257 }
1258 len = dlci->skb->len + overhead;
1259
1260 /* MTU/MRU count only the data bits */
1261 if (len > dlci->mtu) {
1262 if (dlci->adaption == 3) {
1263 /* Over long frame, bin it */
1264 dev_kfree_skb_any(dlci->skb);
1265 dlci->skb = NULL;
1266 return 0;
1267 }
1268 len = dlci->mtu;
1269 } else
1270 last = 1;
1271
1272 size = len + overhead;
1273 msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype);
1274 if (msg == NULL) {
1275 skb_queue_tail(&dlci->skb_list, dlci->skb);
1276 dlci->skb = NULL;
1277 return -ENOMEM;
1278 }
1279 dp = msg->data;
1280
1281 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
1282 /* Flag byte to carry the start/end info */
1283 *dp++ = last << 7 | first << 6 | 1; /* EA */
1284 len--;
1285 }
1286 memcpy(dp, dlci->skb->data, len);
1287 skb_pull(dlci->skb, len);
1288 __gsm_data_queue(dlci, msg);
1289 if (last) {
1290 dev_kfree_skb_any(dlci->skb);
1291 dlci->skb = NULL;
1292 }
1293 return size;
1294}
1295
1296/**
1297 * gsm_dlci_modem_output - try and push modem status out of a DLCI
1298 * @gsm: mux
1299 * @dlci: the DLCI to pull modem status from
1300 * @brk: break signal
1301 *
1302 * Push an empty frame in to the transmit queue to update the modem status
1303 * bits and to transmit an optional break.
1304 *
1305 * Caller must hold the tx_lock of the mux.
1306 */
1307
1308static int gsm_dlci_modem_output(struct gsm_mux *gsm, struct gsm_dlci *dlci,
1309 u8 brk)
1310{
1311 u8 *dp = NULL;
1312 struct gsm_msg *msg;
1313 int size = 0;
1314
1315 /* for modem bits without break data */
1316 switch (dlci->adaption) {
1317 case 1: /* Unstructured */
1318 break;
1319 case 2: /* Unstructured with modem bits. */
1320 size++;
1321 if (brk > 0)
1322 size++;
1323 break;
1324 default:
1325 pr_err("%s: unsupported adaption %d\n", __func__,
1326 dlci->adaption);
1327 return -EINVAL;
1328 }
1329
1330 msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype);
1331 if (!msg) {
1332 pr_err("%s: gsm_data_alloc error", __func__);
1333 return -ENOMEM;
1334 }
1335 dp = msg->data;
1336 switch (dlci->adaption) {
1337 case 1: /* Unstructured */
1338 break;
1339 case 2: /* Unstructured with modem bits. */
1340 if (brk == 0) {
1341 *dp++ = (gsm_encode_modem(dlci) << 1) | EA;
1342 } else {
1343 *dp++ = gsm_encode_modem(dlci) << 1;
1344 *dp++ = (brk << 4) | 2 | EA; /* Length, Break, EA */
1345 }
1346 break;
1347 default:
1348 /* Handled above */
1349 break;
1350 }
1351
1352 __gsm_data_queue(dlci, msg);
1353 return size;
1354}
1355
1356/**
1357 * gsm_dlci_data_sweep - look for data to send
1358 * @gsm: the GSM mux
1359 *
1360 * Sweep the GSM mux channels in priority order looking for ones with
1361 * data to send. We could do with optimising this scan a bit. We aim
1362 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
1363 * TX_THRESH_LO we get called again
1364 *
1365 * FIXME: We should round robin between groups and in theory you can
1366 * renegotiate DLCI priorities with optional stuff. Needs optimising.
1367 */
1368
1369static int gsm_dlci_data_sweep(struct gsm_mux *gsm)
1370{
1371 /* Priority ordering: We should do priority with RR of the groups */
1372 int i, len, ret = 0;
1373 bool sent;
1374 struct gsm_dlci *dlci;
1375
1376 while (gsm->tx_bytes < TX_THRESH_HI) {
1377 for (sent = false, i = 1; i < NUM_DLCI; i++) {
1378 dlci = gsm->dlci[i];
1379 /* skip unused or blocked channel */
1380 if (!dlci || dlci->constipated)
1381 continue;
1382 /* skip channels with invalid state */
1383 if (dlci->state != DLCI_OPEN)
1384 continue;
1385 /* count the sent data per adaption */
1386 if (dlci->adaption < 3 && !dlci->net)
1387 len = gsm_dlci_data_output(gsm, dlci);
1388 else
1389 len = gsm_dlci_data_output_framed(gsm, dlci);
1390 /* on error exit */
1391 if (len < 0)
1392 return ret;
1393 if (len > 0) {
1394 ret++;
1395 sent = true;
1396 /* The lower DLCs can starve the higher DLCs! */
1397 break;
1398 }
1399 /* try next */
1400 }
1401 if (!sent)
1402 break;
1403 }
1404
1405 return ret;
1406}
1407
1408/**
1409 * gsm_dlci_data_kick - transmit if possible
1410 * @dlci: DLCI to kick
1411 *
1412 * Transmit data from this DLCI if the queue is empty. We can't rely on
1413 * a tty wakeup except when we filled the pipe so we need to fire off
1414 * new data ourselves in other cases.
1415 */
1416
1417static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
1418{
1419 unsigned long flags;
1420 int sweep;
1421
1422 if (dlci->constipated)
1423 return;
1424
1425 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
1426 /* If we have nothing running then we need to fire up */
1427 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
1428 if (dlci->gsm->tx_bytes == 0) {
1429 if (dlci->net)
1430 gsm_dlci_data_output_framed(dlci->gsm, dlci);
1431 else
1432 gsm_dlci_data_output(dlci->gsm, dlci);
1433 }
1434 if (sweep)
1435 gsm_dlci_data_sweep(dlci->gsm);
1436 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
1437}
1438
1439/*
1440 * Control message processing
1441 */
1442
1443
1444/**
1445 * gsm_control_command - send a command frame to a control
1446 * @gsm: gsm channel
1447 * @cmd: the command to use
1448 * @data: data to follow encoded info
1449 * @dlen: length of data
1450 *
1451 * Encode up and queue a UI/UIH frame containing our command.
1452 */
1453static int gsm_control_command(struct gsm_mux *gsm, int cmd, const u8 *data,
1454 int dlen)
1455{
1456 struct gsm_msg *msg;
1457 struct gsm_dlci *dlci = gsm->dlci[0];
1458
1459 msg = gsm_data_alloc(gsm, 0, dlen + 2, dlci->ftype);
1460 if (msg == NULL)
1461 return -ENOMEM;
1462
1463 msg->data[0] = (cmd << 1) | CR | EA; /* Set C/R */
1464 msg->data[1] = (dlen << 1) | EA;
1465 memcpy(msg->data + 2, data, dlen);
1466 gsm_data_queue(dlci, msg);
1467
1468 return 0;
1469}
1470
1471/**
1472 * gsm_control_reply - send a response frame to a control
1473 * @gsm: gsm channel
1474 * @cmd: the command to use
1475 * @data: data to follow encoded info
1476 * @dlen: length of data
1477 *
1478 * Encode up and queue a UI/UIH frame containing our response.
1479 */
1480
1481static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data,
1482 int dlen)
1483{
1484 struct gsm_msg *msg;
1485 struct gsm_dlci *dlci = gsm->dlci[0];
1486
1487 msg = gsm_data_alloc(gsm, 0, dlen + 2, dlci->ftype);
1488 if (msg == NULL)
1489 return;
1490 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1491 msg->data[1] = (dlen << 1) | EA;
1492 memcpy(msg->data + 2, data, dlen);
1493 gsm_data_queue(dlci, msg);
1494}
1495
1496/**
1497 * gsm_process_modem - process received modem status
1498 * @tty: virtual tty bound to the DLCI
1499 * @dlci: DLCI to affect
1500 * @modem: modem bits (full EA)
1501 * @slen: number of signal octets
1502 *
1503 * Used when a modem control message or line state inline in adaption
1504 * layer 2 is processed. Sort out the local modem state and throttles
1505 */
1506
1507static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1508 u32 modem, int slen)
1509{
1510 int mlines = 0;
1511 u8 brk = 0;
1512 int fc;
1513
1514 /* The modem status command can either contain one octet (V.24 signals)
1515 * or two octets (V.24 signals + break signals). This is specified in
1516 * section 5.4.6.3.7 of the 07.10 mux spec.
1517 */
1518
1519 if (slen == 1)
1520 modem = modem & 0x7f;
1521 else {
1522 brk = modem & 0x7f;
1523 modem = (modem >> 7) & 0x7f;
1524 }
1525
1526 /* Flow control/ready to communicate */
1527 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1528 if (fc && !dlci->constipated) {
1529 /* Need to throttle our output on this device */
1530 dlci->constipated = true;
1531 } else if (!fc && dlci->constipated) {
1532 dlci->constipated = false;
1533 gsm_dlci_data_kick(dlci);
1534 }
1535
1536 /* Map modem bits */
1537 if (modem & MDM_RTC)
1538 mlines |= TIOCM_DSR | TIOCM_DTR;
1539 if (modem & MDM_RTR)
1540 mlines |= TIOCM_RTS | TIOCM_CTS;
1541 if (modem & MDM_IC)
1542 mlines |= TIOCM_RI;
1543 if (modem & MDM_DV)
1544 mlines |= TIOCM_CD;
1545
1546 /* Carrier drop -> hangup */
1547 if (tty) {
1548 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1549 if (!C_CLOCAL(tty))
1550 tty_hangup(tty);
1551 }
1552 if (brk & 0x01)
1553 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1554 dlci->modem_rx = mlines;
1555 wake_up_interruptible(&dlci->gsm->event);
1556}
1557
1558/**
1559 * gsm_process_negotiation - process received parameters
1560 * @gsm: GSM channel
1561 * @addr: DLCI address
1562 * @cr: command/response
1563 * @params: encoded parameters from the parameter negotiation message
1564 *
1565 * Used when the response for our parameter negotiation command was
1566 * received.
1567 */
1568static int gsm_process_negotiation(struct gsm_mux *gsm, unsigned int addr,
1569 unsigned int cr,
1570 const struct gsm_dlci_param_bits *params)
1571{
1572 struct gsm_dlci *dlci = gsm->dlci[addr];
1573 unsigned int ftype, i, adaption, prio, n1, k;
1574
1575 i = FIELD_GET(PN_I_CL_FIELD_FTYPE, params->i_cl_bits);
1576 adaption = FIELD_GET(PN_I_CL_FIELD_ADAPTION, params->i_cl_bits) + 1;
1577 prio = FIELD_GET(PN_P_FIELD_PRIO, params->p_bits);
1578 n1 = FIELD_GET(PN_N_FIELD_N1, get_unaligned_le16(¶ms->n_bits));
1579 k = FIELD_GET(PN_K_FIELD_K, params->k_bits);
1580
1581 if (n1 < MIN_MTU) {
1582 if (debug & DBG_ERRORS)
1583 pr_info("%s N1 out of range in PN\n", __func__);
1584 return -EINVAL;
1585 }
1586
1587 switch (i) {
1588 case 0x00:
1589 ftype = UIH;
1590 break;
1591 case 0x01:
1592 ftype = UI;
1593 break;
1594 case 0x02: /* I frames are not supported */
1595 if (debug & DBG_ERRORS)
1596 pr_info("%s unsupported I frame request in PN\n",
1597 __func__);
1598 gsm->unsupported++;
1599 return -EINVAL;
1600 default:
1601 if (debug & DBG_ERRORS)
1602 pr_info("%s i out of range in PN\n", __func__);
1603 return -EINVAL;
1604 }
1605
1606 if (!cr && gsm->initiator) {
1607 if (adaption != dlci->adaption) {
1608 if (debug & DBG_ERRORS)
1609 pr_info("%s invalid adaption %d in PN\n",
1610 __func__, adaption);
1611 return -EINVAL;
1612 }
1613 if (prio != dlci->prio) {
1614 if (debug & DBG_ERRORS)
1615 pr_info("%s invalid priority %d in PN",
1616 __func__, prio);
1617 return -EINVAL;
1618 }
1619 if (n1 > gsm->mru || n1 > dlci->mtu) {
1620 /* We requested a frame size but the other party wants
1621 * to send larger frames. The standard allows only a
1622 * smaller response value than requested (5.4.6.3.1).
1623 */
1624 if (debug & DBG_ERRORS)
1625 pr_info("%s invalid N1 %d in PN\n", __func__,
1626 n1);
1627 return -EINVAL;
1628 }
1629 dlci->mtu = n1;
1630 if (ftype != dlci->ftype) {
1631 if (debug & DBG_ERRORS)
1632 pr_info("%s invalid i %d in PN\n", __func__, i);
1633 return -EINVAL;
1634 }
1635 if (ftype != UI && ftype != UIH && k > dlci->k) {
1636 if (debug & DBG_ERRORS)
1637 pr_info("%s invalid k %d in PN\n", __func__, k);
1638 return -EINVAL;
1639 }
1640 dlci->k = k;
1641 } else if (cr && !gsm->initiator) {
1642 /* Only convergence layer type 1 and 2 are supported. */
1643 if (adaption != 1 && adaption != 2) {
1644 if (debug & DBG_ERRORS)
1645 pr_info("%s invalid adaption %d in PN\n",
1646 __func__, adaption);
1647 return -EINVAL;
1648 }
1649 dlci->adaption = adaption;
1650 if (n1 > gsm->mru) {
1651 /* Propose a smaller value */
1652 dlci->mtu = gsm->mru;
1653 } else if (n1 > MAX_MTU) {
1654 /* Propose a smaller value */
1655 dlci->mtu = MAX_MTU;
1656 } else {
1657 dlci->mtu = n1;
1658 }
1659 dlci->prio = prio;
1660 dlci->ftype = ftype;
1661 dlci->k = k;
1662 } else {
1663 return -EINVAL;
1664 }
1665
1666 return 0;
1667}
1668
1669/**
1670 * gsm_control_modem - modem status received
1671 * @gsm: GSM channel
1672 * @data: data following command
1673 * @clen: command length
1674 *
1675 * We have received a modem status control message. This is used by
1676 * the GSM mux protocol to pass virtual modem line status and optionally
1677 * to indicate break signals. Unpack it, convert to Linux representation
1678 * and if need be stuff a break message down the tty.
1679 */
1680
1681static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
1682{
1683 unsigned int addr = 0;
1684 unsigned int modem = 0;
1685 struct gsm_dlci *dlci;
1686 int len = clen;
1687 int cl = clen;
1688 const u8 *dp = data;
1689 struct tty_struct *tty;
1690
1691 len = gsm_read_ea_val(&addr, data, cl);
1692 if (len < 1)
1693 return;
1694
1695 addr >>= 1;
1696 /* Closed port, or invalid ? */
1697 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1698 return;
1699 dlci = gsm->dlci[addr];
1700
1701 /* Must be at least one byte following the EA */
1702 if ((cl - len) < 1)
1703 return;
1704
1705 dp += len;
1706 cl -= len;
1707
1708 /* get the modem status */
1709 len = gsm_read_ea_val(&modem, dp, cl);
1710 if (len < 1)
1711 return;
1712
1713 tty = tty_port_tty_get(&dlci->port);
1714 gsm_process_modem(tty, dlci, modem, cl);
1715 if (tty) {
1716 tty_wakeup(tty);
1717 tty_kref_put(tty);
1718 }
1719 gsm_control_reply(gsm, CMD_MSC, data, clen);
1720}
1721
1722/**
1723 * gsm_control_negotiation - parameter negotiation received
1724 * @gsm: GSM channel
1725 * @cr: command/response flag
1726 * @data: data following command
1727 * @dlen: data length
1728 *
1729 * We have received a parameter negotiation message. This is used by
1730 * the GSM mux protocol to configure protocol parameters for a new DLCI.
1731 */
1732static void gsm_control_negotiation(struct gsm_mux *gsm, unsigned int cr,
1733 const u8 *data, unsigned int dlen)
1734{
1735 unsigned int addr;
1736 struct gsm_dlci_param_bits pn_reply;
1737 struct gsm_dlci *dlci;
1738 struct gsm_dlci_param_bits *params;
1739
1740 if (dlen < sizeof(struct gsm_dlci_param_bits)) {
1741 gsm->open_error++;
1742 return;
1743 }
1744
1745 /* Invalid DLCI? */
1746 params = (struct gsm_dlci_param_bits *)data;
1747 addr = FIELD_GET(PN_D_FIELD_DLCI, params->d_bits);
1748 if (addr == 0 || addr >= NUM_DLCI || !gsm->dlci[addr]) {
1749 gsm->open_error++;
1750 return;
1751 }
1752 dlci = gsm->dlci[addr];
1753
1754 /* Too late for parameter negotiation? */
1755 if ((!cr && dlci->state == DLCI_OPENING) || dlci->state == DLCI_OPEN) {
1756 gsm->open_error++;
1757 return;
1758 }
1759
1760 /* Process the received parameters */
1761 if (gsm_process_negotiation(gsm, addr, cr, params) != 0) {
1762 /* Negotiation failed. Close the link. */
1763 if (debug & DBG_ERRORS)
1764 pr_info("%s PN failed\n", __func__);
1765 gsm->open_error++;
1766 gsm_dlci_close(dlci);
1767 return;
1768 }
1769
1770 if (cr) {
1771 /* Reply command with accepted parameters. */
1772 if (gsm_encode_params(dlci, &pn_reply) == 0)
1773 gsm_control_reply(gsm, CMD_PN, (const u8 *)&pn_reply,
1774 sizeof(pn_reply));
1775 else if (debug & DBG_ERRORS)
1776 pr_info("%s PN invalid\n", __func__);
1777 } else if (dlci->state == DLCI_CONFIGURE) {
1778 /* Proceed with link setup by sending SABM before UA */
1779 dlci->state = DLCI_OPENING;
1780 gsm_command(gsm, dlci->addr, SABM|PF);
1781 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1782 } else {
1783 if (debug & DBG_ERRORS)
1784 pr_info("%s PN in invalid state\n", __func__);
1785 gsm->open_error++;
1786 }
1787}
1788
1789/**
1790 * gsm_control_rls - remote line status
1791 * @gsm: GSM channel
1792 * @data: data bytes
1793 * @clen: data length
1794 *
1795 * The modem sends us a two byte message on the control channel whenever
1796 * it wishes to send us an error state from the virtual link. Stuff
1797 * this into the uplink tty if present
1798 */
1799
1800static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen)
1801{
1802 struct tty_port *port;
1803 unsigned int addr = 0;
1804 u8 bits;
1805 int len = clen;
1806 const u8 *dp = data;
1807
1808 while (gsm_read_ea(&addr, *dp++) == 0) {
1809 len--;
1810 if (len == 0)
1811 return;
1812 }
1813 /* Must be at least one byte following ea */
1814 len--;
1815 if (len <= 0)
1816 return;
1817 addr >>= 1;
1818 /* Closed port, or invalid ? */
1819 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1820 return;
1821 /* No error ? */
1822 bits = *dp;
1823 if ((bits & 1) == 0)
1824 return;
1825
1826 port = &gsm->dlci[addr]->port;
1827
1828 if (bits & 2)
1829 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1830 if (bits & 4)
1831 tty_insert_flip_char(port, 0, TTY_PARITY);
1832 if (bits & 8)
1833 tty_insert_flip_char(port, 0, TTY_FRAME);
1834
1835 tty_flip_buffer_push(port);
1836
1837 gsm_control_reply(gsm, CMD_RLS, data, clen);
1838}
1839
1840static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1841
1842/**
1843 * gsm_control_message - DLCI 0 control processing
1844 * @gsm: our GSM mux
1845 * @command: the command EA
1846 * @data: data beyond the command/length EAs
1847 * @clen: length
1848 *
1849 * Input processor for control messages from the other end of the link.
1850 * Processes the incoming request and queues a response frame or an
1851 * NSC response if not supported
1852 */
1853
1854static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1855 const u8 *data, int clen)
1856{
1857 u8 buf[1];
1858
1859 switch (command) {
1860 case CMD_CLD: {
1861 struct gsm_dlci *dlci = gsm->dlci[0];
1862 /* Modem wishes to close down */
1863 if (dlci) {
1864 dlci->dead = true;
1865 gsm->dead = true;
1866 gsm_dlci_begin_close(dlci);
1867 }
1868 }
1869 break;
1870 case CMD_TEST:
1871 /* Modem wishes to test, reply with the data */
1872 gsm_control_reply(gsm, CMD_TEST, data, clen);
1873 break;
1874 case CMD_FCON:
1875 /* Modem can accept data again */
1876 gsm->constipated = false;
1877 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1878 /* Kick the link in case it is idling */
1879 gsmld_write_trigger(gsm);
1880 break;
1881 case CMD_FCOFF:
1882 /* Modem wants us to STFU */
1883 gsm->constipated = true;
1884 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1885 break;
1886 case CMD_MSC:
1887 /* Out of band modem line change indicator for a DLCI */
1888 gsm_control_modem(gsm, data, clen);
1889 break;
1890 case CMD_RLS:
1891 /* Out of band error reception for a DLCI */
1892 gsm_control_rls(gsm, data, clen);
1893 break;
1894 case CMD_PSC:
1895 /* Modem wishes to enter power saving state */
1896 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1897 break;
1898 /* Optional commands */
1899 case CMD_PN:
1900 /* Modem sends a parameter negotiation command */
1901 gsm_control_negotiation(gsm, 1, data, clen);
1902 break;
1903 /* Optional unsupported commands */
1904 case CMD_RPN: /* Remote port negotiation */
1905 case CMD_SNC: /* Service negotiation command */
1906 gsm->unsupported++;
1907 fallthrough;
1908 default:
1909 /* Reply to bad commands with an NSC */
1910 buf[0] = command;
1911 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1912 break;
1913 }
1914}
1915
1916/**
1917 * gsm_control_response - process a response to our control
1918 * @gsm: our GSM mux
1919 * @command: the command (response) EA
1920 * @data: data beyond the command/length EA
1921 * @clen: length
1922 *
1923 * Process a response to an outstanding command. We only allow a single
1924 * control message in flight so this is fairly easy. All the clean up
1925 * is done by the caller, we just update the fields, flag it as done
1926 * and return
1927 */
1928
1929static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1930 const u8 *data, int clen)
1931{
1932 struct gsm_control *ctrl;
1933 struct gsm_dlci *dlci;
1934 unsigned long flags;
1935
1936 spin_lock_irqsave(&gsm->control_lock, flags);
1937
1938 ctrl = gsm->pending_cmd;
1939 dlci = gsm->dlci[0];
1940 command |= 1;
1941 /* Does the reply match our command */
1942 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1943 /* Our command was replied to, kill the retry timer */
1944 del_timer(&gsm->t2_timer);
1945 gsm->pending_cmd = NULL;
1946 /* Rejected by the other end */
1947 if (command == CMD_NSC)
1948 ctrl->error = -EOPNOTSUPP;
1949 ctrl->done = 1;
1950 wake_up(&gsm->event);
1951 /* Or did we receive the PN response to our PN command */
1952 } else if (command == CMD_PN) {
1953 gsm_control_negotiation(gsm, 0, data, clen);
1954 /* Or did we receive the TEST response to our TEST command */
1955 } else if (command == CMD_TEST && clen == 1 && *data == gsm->ka_num) {
1956 gsm->ka_retries = -1; /* trigger new keep-alive message */
1957 if (dlci && !dlci->dead)
1958 mod_timer(&gsm->ka_timer, jiffies + gsm->keep_alive * HZ / 100);
1959 }
1960 spin_unlock_irqrestore(&gsm->control_lock, flags);
1961}
1962
1963/**
1964 * gsm_control_keep_alive - check timeout or start keep-alive
1965 * @t: timer contained in our gsm object
1966 *
1967 * Called off the keep-alive timer expiry signaling that our link
1968 * partner is not responding anymore. Link will be closed.
1969 * This is also called to startup our timer.
1970 */
1971
1972static void gsm_control_keep_alive(struct timer_list *t)
1973{
1974 struct gsm_mux *gsm = from_timer(gsm, t, ka_timer);
1975 unsigned long flags;
1976
1977 spin_lock_irqsave(&gsm->control_lock, flags);
1978 if (gsm->ka_num && gsm->ka_retries == 0) {
1979 /* Keep-alive expired -> close the link */
1980 if (debug & DBG_ERRORS)
1981 pr_debug("%s keep-alive timed out\n", __func__);
1982 spin_unlock_irqrestore(&gsm->control_lock, flags);
1983 if (gsm->dlci[0])
1984 gsm_dlci_begin_close(gsm->dlci[0]);
1985 return;
1986 } else if (gsm->keep_alive && gsm->dlci[0] && !gsm->dlci[0]->dead) {
1987 if (gsm->ka_retries > 0) {
1988 /* T2 expired for keep-alive -> resend */
1989 gsm->ka_retries--;
1990 } else {
1991 /* Start keep-alive timer */
1992 gsm->ka_num++;
1993 if (!gsm->ka_num)
1994 gsm->ka_num++;
1995 gsm->ka_retries = (signed int)gsm->n2;
1996 }
1997 gsm_control_command(gsm, CMD_TEST, &gsm->ka_num,
1998 sizeof(gsm->ka_num));
1999 mod_timer(&gsm->ka_timer,
2000 jiffies + gsm->t2 * HZ / 100);
2001 }
2002 spin_unlock_irqrestore(&gsm->control_lock, flags);
2003}
2004
2005/**
2006 * gsm_control_transmit - send control packet
2007 * @gsm: gsm mux
2008 * @ctrl: frame to send
2009 *
2010 * Send out a pending control command (called under control lock)
2011 */
2012
2013static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
2014{
2015 gsm_control_command(gsm, ctrl->cmd, ctrl->data, ctrl->len);
2016}
2017
2018/**
2019 * gsm_control_retransmit - retransmit a control frame
2020 * @t: timer contained in our gsm object
2021 *
2022 * Called off the T2 timer expiry in order to retransmit control frames
2023 * that have been lost in the system somewhere. The control_lock protects
2024 * us from colliding with another sender or a receive completion event.
2025 * In that situation the timer may still occur in a small window but
2026 * gsm->pending_cmd will be NULL and we just let the timer expire.
2027 */
2028
2029static void gsm_control_retransmit(struct timer_list *t)
2030{
2031 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer);
2032 struct gsm_control *ctrl;
2033 unsigned long flags;
2034 spin_lock_irqsave(&gsm->control_lock, flags);
2035 ctrl = gsm->pending_cmd;
2036 if (ctrl) {
2037 if (gsm->cretries == 0 || !gsm->dlci[0] || gsm->dlci[0]->dead) {
2038 gsm->pending_cmd = NULL;
2039 ctrl->error = -ETIMEDOUT;
2040 ctrl->done = 1;
2041 spin_unlock_irqrestore(&gsm->control_lock, flags);
2042 wake_up(&gsm->event);
2043 return;
2044 }
2045 gsm->cretries--;
2046 gsm_control_transmit(gsm, ctrl);
2047 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
2048 }
2049 spin_unlock_irqrestore(&gsm->control_lock, flags);
2050}
2051
2052/**
2053 * gsm_control_send - send a control frame on DLCI 0
2054 * @gsm: the GSM channel
2055 * @command: command to send including CR bit
2056 * @data: bytes of data (must be kmalloced)
2057 * @clen: length of the block to send
2058 *
2059 * Queue and dispatch a control command. Only one command can be
2060 * active at a time. In theory more can be outstanding but the matching
2061 * gets really complicated so for now stick to one outstanding.
2062 */
2063
2064static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
2065 unsigned int command, u8 *data, int clen)
2066{
2067 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
2068 GFP_ATOMIC);
2069 unsigned long flags;
2070 if (ctrl == NULL)
2071 return NULL;
2072retry:
2073 wait_event(gsm->event, gsm->pending_cmd == NULL);
2074 spin_lock_irqsave(&gsm->control_lock, flags);
2075 if (gsm->pending_cmd != NULL) {
2076 spin_unlock_irqrestore(&gsm->control_lock, flags);
2077 goto retry;
2078 }
2079 ctrl->cmd = command;
2080 ctrl->data = data;
2081 ctrl->len = clen;
2082 gsm->pending_cmd = ctrl;
2083
2084 /* If DLCI0 is in ADM mode skip retries, it won't respond */
2085 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
2086 gsm->cretries = 0;
2087 else
2088 gsm->cretries = gsm->n2;
2089
2090 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
2091 gsm_control_transmit(gsm, ctrl);
2092 spin_unlock_irqrestore(&gsm->control_lock, flags);
2093 return ctrl;
2094}
2095
2096/**
2097 * gsm_control_wait - wait for a control to finish
2098 * @gsm: GSM mux
2099 * @control: control we are waiting on
2100 *
2101 * Waits for the control to complete or time out. Frees any used
2102 * resources and returns 0 for success, or an error if the remote
2103 * rejected or ignored the request.
2104 */
2105
2106static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
2107{
2108 int err;
2109 wait_event(gsm->event, control->done == 1);
2110 err = control->error;
2111 kfree(control);
2112 return err;
2113}
2114
2115
2116/*
2117 * DLCI level handling: Needs krefs
2118 */
2119
2120/*
2121 * State transitions and timers
2122 */
2123
2124/**
2125 * gsm_dlci_close - a DLCI has closed
2126 * @dlci: DLCI that closed
2127 *
2128 * Perform processing when moving a DLCI into closed state. If there
2129 * is an attached tty this is hung up
2130 */
2131
2132static void gsm_dlci_close(struct gsm_dlci *dlci)
2133{
2134 del_timer(&dlci->t1);
2135 if (debug & DBG_ERRORS)
2136 pr_debug("DLCI %d goes closed.\n", dlci->addr);
2137 dlci->state = DLCI_CLOSED;
2138 /* Prevent us from sending data before the link is up again */
2139 dlci->constipated = true;
2140 if (dlci->addr != 0) {
2141 tty_port_tty_hangup(&dlci->port, false);
2142 gsm_dlci_clear_queues(dlci->gsm, dlci);
2143 /* Ensure that gsmtty_open() can return. */
2144 tty_port_set_initialized(&dlci->port, false);
2145 wake_up_interruptible(&dlci->port.open_wait);
2146 } else {
2147 del_timer(&dlci->gsm->ka_timer);
2148 dlci->gsm->dead = true;
2149 }
2150 /* A DLCI 0 close is a MUX termination so we need to kick that
2151 back to userspace somehow */
2152 gsm_dlci_data_kick(dlci);
2153 wake_up_all(&dlci->gsm->event);
2154}
2155
2156/**
2157 * gsm_dlci_open - a DLCI has opened
2158 * @dlci: DLCI that opened
2159 *
2160 * Perform processing when moving a DLCI into open state.
2161 */
2162
2163static void gsm_dlci_open(struct gsm_dlci *dlci)
2164{
2165 struct gsm_mux *gsm = dlci->gsm;
2166
2167 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
2168 open -> open */
2169 del_timer(&dlci->t1);
2170 /* This will let a tty open continue */
2171 dlci->state = DLCI_OPEN;
2172 dlci->constipated = false;
2173 if (debug & DBG_ERRORS)
2174 pr_debug("DLCI %d goes open.\n", dlci->addr);
2175 /* Send current modem state */
2176 if (dlci->addr) {
2177 gsm_modem_update(dlci, 0);
2178 } else {
2179 /* Start keep-alive control */
2180 gsm->ka_num = 0;
2181 gsm->ka_retries = -1;
2182 mod_timer(&gsm->ka_timer,
2183 jiffies + gsm->keep_alive * HZ / 100);
2184 }
2185 gsm_dlci_data_kick(dlci);
2186 wake_up(&dlci->gsm->event);
2187}
2188
2189/**
2190 * gsm_dlci_negotiate - start parameter negotiation
2191 * @dlci: DLCI to open
2192 *
2193 * Starts the parameter negotiation for the new DLCI. This needs to be done
2194 * before the DLCI initialized the channel via SABM.
2195 */
2196static int gsm_dlci_negotiate(struct gsm_dlci *dlci)
2197{
2198 struct gsm_mux *gsm = dlci->gsm;
2199 struct gsm_dlci_param_bits params;
2200 int ret;
2201
2202 ret = gsm_encode_params(dlci, ¶ms);
2203 if (ret != 0)
2204 return ret;
2205
2206 /* We cannot asynchronous wait for the command response with
2207 * gsm_command() and gsm_control_wait() at this point.
2208 */
2209 ret = gsm_control_command(gsm, CMD_PN, (const u8 *)¶ms,
2210 sizeof(params));
2211
2212 return ret;
2213}
2214
2215/**
2216 * gsm_dlci_t1 - T1 timer expiry
2217 * @t: timer contained in the DLCI that opened
2218 *
2219 * The T1 timer handles retransmits of control frames (essentially of
2220 * SABM and DISC). We resend the command until the retry count runs out
2221 * in which case an opening port goes back to closed and a closing port
2222 * is simply put into closed state (any further frames from the other
2223 * end will get a DM response)
2224 *
2225 * Some control dlci can stay in ADM mode with other dlci working just
2226 * fine. In that case we can just keep the control dlci open after the
2227 * DLCI_OPENING retries time out.
2228 */
2229
2230static void gsm_dlci_t1(struct timer_list *t)
2231{
2232 struct gsm_dlci *dlci = from_timer(dlci, t, t1);
2233 struct gsm_mux *gsm = dlci->gsm;
2234
2235 switch (dlci->state) {
2236 case DLCI_CONFIGURE:
2237 if (dlci->retries && gsm_dlci_negotiate(dlci) == 0) {
2238 dlci->retries--;
2239 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2240 } else {
2241 gsm->open_error++;
2242 gsm_dlci_begin_close(dlci); /* prevent half open link */
2243 }
2244 break;
2245 case DLCI_OPENING:
2246 if (dlci->retries) {
2247 dlci->retries--;
2248 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
2249 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2250 } else if (!dlci->addr && gsm->control == (DM | PF)) {
2251 if (debug & DBG_ERRORS)
2252 pr_info("DLCI %d opening in ADM mode.\n",
2253 dlci->addr);
2254 dlci->mode = DLCI_MODE_ADM;
2255 gsm_dlci_open(dlci);
2256 } else {
2257 gsm->open_error++;
2258 gsm_dlci_begin_close(dlci); /* prevent half open link */
2259 }
2260
2261 break;
2262 case DLCI_CLOSING:
2263 if (dlci->retries) {
2264 dlci->retries--;
2265 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
2266 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2267 } else
2268 gsm_dlci_close(dlci);
2269 break;
2270 default:
2271 pr_debug("%s: unhandled state: %d\n", __func__, dlci->state);
2272 break;
2273 }
2274}
2275
2276/**
2277 * gsm_dlci_begin_open - start channel open procedure
2278 * @dlci: DLCI to open
2279 *
2280 * Commence opening a DLCI from the Linux side. We issue SABM messages
2281 * to the modem which should then reply with a UA or ADM, at which point
2282 * we will move into open state. Opening is done asynchronously with retry
2283 * running off timers and the responses.
2284 * Parameter negotiation is performed before SABM if required.
2285 */
2286
2287static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
2288{
2289 struct gsm_mux *gsm = dlci ? dlci->gsm : NULL;
2290 bool need_pn = false;
2291
2292 if (!gsm)
2293 return;
2294
2295 if (dlci->addr != 0) {
2296 if (gsm->adaption != 1 || gsm->adaption != dlci->adaption)
2297 need_pn = true;
2298 if (dlci->prio != (roundup(dlci->addr + 1, 8) - 1))
2299 need_pn = true;
2300 if (gsm->ftype != dlci->ftype)
2301 need_pn = true;
2302 }
2303
2304 switch (dlci->state) {
2305 case DLCI_CLOSED:
2306 case DLCI_WAITING_CONFIG:
2307 case DLCI_CLOSING:
2308 dlci->retries = gsm->n2;
2309 if (!need_pn) {
2310 dlci->state = DLCI_OPENING;
2311 gsm_command(gsm, dlci->addr, SABM|PF);
2312 } else {
2313 /* Configure DLCI before setup */
2314 dlci->state = DLCI_CONFIGURE;
2315 if (gsm_dlci_negotiate(dlci) != 0) {
2316 gsm_dlci_close(dlci);
2317 return;
2318 }
2319 }
2320 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2321 break;
2322 default:
2323 break;
2324 }
2325}
2326
2327/**
2328 * gsm_dlci_set_opening - change state to opening
2329 * @dlci: DLCI to open
2330 *
2331 * Change internal state to wait for DLCI open from initiator side.
2332 * We set off timers and responses upon reception of an SABM.
2333 */
2334static void gsm_dlci_set_opening(struct gsm_dlci *dlci)
2335{
2336 switch (dlci->state) {
2337 case DLCI_CLOSED:
2338 case DLCI_WAITING_CONFIG:
2339 case DLCI_CLOSING:
2340 dlci->state = DLCI_OPENING;
2341 break;
2342 default:
2343 break;
2344 }
2345}
2346
2347/**
2348 * gsm_dlci_set_wait_config - wait for channel configuration
2349 * @dlci: DLCI to configure
2350 *
2351 * Wait for a DLCI configuration from the application.
2352 */
2353static void gsm_dlci_set_wait_config(struct gsm_dlci *dlci)
2354{
2355 switch (dlci->state) {
2356 case DLCI_CLOSED:
2357 case DLCI_CLOSING:
2358 dlci->state = DLCI_WAITING_CONFIG;
2359 break;
2360 default:
2361 break;
2362 }
2363}
2364
2365/**
2366 * gsm_dlci_begin_close - start channel open procedure
2367 * @dlci: DLCI to open
2368 *
2369 * Commence closing a DLCI from the Linux side. We issue DISC messages
2370 * to the modem which should then reply with a UA, at which point we
2371 * will move into closed state. Closing is done asynchronously with retry
2372 * off timers. We may also receive a DM reply from the other end which
2373 * indicates the channel was already closed.
2374 */
2375
2376static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
2377{
2378 struct gsm_mux *gsm = dlci->gsm;
2379 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
2380 return;
2381 dlci->retries = gsm->n2;
2382 dlci->state = DLCI_CLOSING;
2383 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
2384 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2385 wake_up_interruptible(&gsm->event);
2386}
2387
2388/**
2389 * gsm_dlci_data - data arrived
2390 * @dlci: channel
2391 * @data: block of bytes received
2392 * @clen: length of received block
2393 *
2394 * A UI or UIH frame has arrived which contains data for a channel
2395 * other than the control channel. If the relevant virtual tty is
2396 * open we shovel the bits down it, if not we drop them.
2397 */
2398
2399static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
2400{
2401 /* krefs .. */
2402 struct tty_port *port = &dlci->port;
2403 struct tty_struct *tty;
2404 unsigned int modem = 0;
2405 int len;
2406
2407 if (debug & DBG_TTY)
2408 pr_debug("%d bytes for tty\n", clen);
2409 switch (dlci->adaption) {
2410 /* Unsupported types */
2411 case 4: /* Packetised interruptible data */
2412 break;
2413 case 3: /* Packetised uininterruptible voice/data */
2414 break;
2415 case 2: /* Asynchronous serial with line state in each frame */
2416 len = gsm_read_ea_val(&modem, data, clen);
2417 if (len < 1)
2418 return;
2419 tty = tty_port_tty_get(port);
2420 if (tty) {
2421 gsm_process_modem(tty, dlci, modem, len);
2422 tty_wakeup(tty);
2423 tty_kref_put(tty);
2424 }
2425 /* Skip processed modem data */
2426 data += len;
2427 clen -= len;
2428 fallthrough;
2429 case 1: /* Line state will go via DLCI 0 controls only */
2430 default:
2431 tty_insert_flip_string(port, data, clen);
2432 tty_flip_buffer_push(port);
2433 }
2434}
2435
2436/**
2437 * gsm_dlci_command - data arrived on control channel
2438 * @dlci: channel
2439 * @data: block of bytes received
2440 * @len: length of received block
2441 *
2442 * A UI or UIH frame has arrived which contains data for DLCI 0 the
2443 * control channel. This should contain a command EA followed by
2444 * control data bytes. The command EA contains a command/response bit
2445 * and we divide up the work accordingly.
2446 */
2447
2448static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
2449{
2450 /* See what command is involved */
2451 unsigned int command = 0;
2452 unsigned int clen = 0;
2453 unsigned int dlen;
2454
2455 /* read the command */
2456 dlen = gsm_read_ea_val(&command, data, len);
2457 len -= dlen;
2458 data += dlen;
2459
2460 /* read any control data */
2461 dlen = gsm_read_ea_val(&clen, data, len);
2462 len -= dlen;
2463 data += dlen;
2464
2465 /* Malformed command? */
2466 if (clen > len) {
2467 dlci->gsm->malformed++;
2468 return;
2469 }
2470
2471 if (command & 1)
2472 gsm_control_message(dlci->gsm, command, data, clen);
2473 else
2474 gsm_control_response(dlci->gsm, command, data, clen);
2475}
2476
2477/**
2478 * gsm_kick_timer - transmit if possible
2479 * @t: timer contained in our gsm object
2480 *
2481 * Transmit data from DLCIs if the queue is empty. We can't rely on
2482 * a tty wakeup except when we filled the pipe so we need to fire off
2483 * new data ourselves in other cases.
2484 */
2485static void gsm_kick_timer(struct timer_list *t)
2486{
2487 struct gsm_mux *gsm = from_timer(gsm, t, kick_timer);
2488 unsigned long flags;
2489 int sent = 0;
2490
2491 spin_lock_irqsave(&gsm->tx_lock, flags);
2492 /* If we have nothing running then we need to fire up */
2493 if (gsm->tx_bytes < TX_THRESH_LO)
2494 sent = gsm_dlci_data_sweep(gsm);
2495 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2496
2497 if (sent && debug & DBG_DATA)
2498 pr_info("%s TX queue stalled\n", __func__);
2499}
2500
2501/**
2502 * gsm_dlci_copy_config_values - copy DLCI configuration
2503 * @dlci: source DLCI
2504 * @dc: configuration structure to fill
2505 */
2506static void gsm_dlci_copy_config_values(struct gsm_dlci *dlci, struct gsm_dlci_config *dc)
2507{
2508 memset(dc, 0, sizeof(*dc));
2509 dc->channel = (u32)dlci->addr;
2510 dc->adaption = (u32)dlci->adaption;
2511 dc->mtu = (u32)dlci->mtu;
2512 dc->priority = (u32)dlci->prio;
2513 if (dlci->ftype == UIH)
2514 dc->i = 1;
2515 else
2516 dc->i = 2;
2517 dc->k = (u32)dlci->k;
2518}
2519
2520/**
2521 * gsm_dlci_config - configure DLCI from configuration
2522 * @dlci: DLCI to configure
2523 * @dc: DLCI configuration
2524 * @open: open DLCI after configuration?
2525 */
2526static int gsm_dlci_config(struct gsm_dlci *dlci, struct gsm_dlci_config *dc, int open)
2527{
2528 struct gsm_mux *gsm;
2529 bool need_restart = false;
2530 bool need_open = false;
2531 unsigned int i;
2532
2533 /*
2534 * Check that userspace doesn't put stuff in here to prevent breakages
2535 * in the future.
2536 */
2537 for (i = 0; i < ARRAY_SIZE(dc->reserved); i++)
2538 if (dc->reserved[i])
2539 return -EINVAL;
2540
2541 if (!dlci)
2542 return -EINVAL;
2543 gsm = dlci->gsm;
2544
2545 /* Stuff we don't support yet - I frame transport */
2546 if (dc->adaption != 1 && dc->adaption != 2)
2547 return -EOPNOTSUPP;
2548 if (dc->mtu > MAX_MTU || dc->mtu < MIN_MTU || dc->mtu > gsm->mru)
2549 return -EINVAL;
2550 if (dc->priority >= 64)
2551 return -EINVAL;
2552 if (dc->i == 0 || dc->i > 2) /* UIH and UI only */
2553 return -EINVAL;
2554 if (dc->k > 7)
2555 return -EINVAL;
2556 if (dc->flags & ~GSM_FL_RESTART) /* allow future extensions */
2557 return -EINVAL;
2558
2559 /*
2560 * See what is needed for reconfiguration
2561 */
2562 /* Framing fields */
2563 if (dc->adaption != dlci->adaption)
2564 need_restart = true;
2565 if (dc->mtu != dlci->mtu)
2566 need_restart = true;
2567 if (dc->i != dlci->ftype)
2568 need_restart = true;
2569 /* Requires care */
2570 if (dc->priority != dlci->prio)
2571 need_restart = true;
2572 if (dc->flags & GSM_FL_RESTART)
2573 need_restart = true;
2574
2575 if ((open && gsm->wait_config) || need_restart)
2576 need_open = true;
2577 if (dlci->state == DLCI_WAITING_CONFIG) {
2578 need_restart = false;
2579 need_open = true;
2580 }
2581
2582 /*
2583 * Close down what is needed, restart and initiate the new
2584 * configuration.
2585 */
2586 if (need_restart) {
2587 gsm_dlci_begin_close(dlci);
2588 wait_event_interruptible(gsm->event, dlci->state == DLCI_CLOSED);
2589 if (signal_pending(current))
2590 return -EINTR;
2591 }
2592 /*
2593 * Setup the new configuration values
2594 */
2595 dlci->adaption = (int)dc->adaption;
2596
2597 if (dc->mtu)
2598 dlci->mtu = (unsigned int)dc->mtu;
2599 else
2600 dlci->mtu = gsm->mtu;
2601
2602 if (dc->priority)
2603 dlci->prio = (u8)dc->priority;
2604 else
2605 dlci->prio = roundup(dlci->addr + 1, 8) - 1;
2606
2607 if (dc->i == 1)
2608 dlci->ftype = UIH;
2609 else if (dc->i == 2)
2610 dlci->ftype = UI;
2611
2612 if (dc->k)
2613 dlci->k = (u8)dc->k;
2614 else
2615 dlci->k = gsm->k;
2616
2617 if (need_open) {
2618 if (gsm->initiator)
2619 gsm_dlci_begin_open(dlci);
2620 else
2621 gsm_dlci_set_opening(dlci);
2622 }
2623
2624 return 0;
2625}
2626
2627/*
2628 * Allocate/Free DLCI channels
2629 */
2630
2631/**
2632 * gsm_dlci_alloc - allocate a DLCI
2633 * @gsm: GSM mux
2634 * @addr: address of the DLCI
2635 *
2636 * Allocate and install a new DLCI object into the GSM mux.
2637 *
2638 * FIXME: review locking races
2639 */
2640
2641static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
2642{
2643 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
2644 if (dlci == NULL)
2645 return NULL;
2646 spin_lock_init(&dlci->lock);
2647 mutex_init(&dlci->mutex);
2648 if (kfifo_alloc(&dlci->fifo, TX_SIZE, GFP_KERNEL) < 0) {
2649 kfree(dlci);
2650 return NULL;
2651 }
2652
2653 skb_queue_head_init(&dlci->skb_list);
2654 timer_setup(&dlci->t1, gsm_dlci_t1, 0);
2655 tty_port_init(&dlci->port);
2656 dlci->port.ops = &gsm_port_ops;
2657 dlci->gsm = gsm;
2658 dlci->addr = addr;
2659 dlci->adaption = gsm->adaption;
2660 dlci->mtu = gsm->mtu;
2661 if (addr == 0)
2662 dlci->prio = 0;
2663 else
2664 dlci->prio = roundup(addr + 1, 8) - 1;
2665 dlci->ftype = gsm->ftype;
2666 dlci->k = gsm->k;
2667 dlci->state = DLCI_CLOSED;
2668 if (addr) {
2669 dlci->data = gsm_dlci_data;
2670 /* Prevent us from sending data before the link is up */
2671 dlci->constipated = true;
2672 } else {
2673 dlci->data = gsm_dlci_command;
2674 }
2675 gsm->dlci[addr] = dlci;
2676 return dlci;
2677}
2678
2679/**
2680 * gsm_dlci_free - free DLCI
2681 * @port: tty port for DLCI to free
2682 *
2683 * Free up a DLCI.
2684 *
2685 * Can sleep.
2686 */
2687static void gsm_dlci_free(struct tty_port *port)
2688{
2689 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2690
2691 timer_shutdown_sync(&dlci->t1);
2692 dlci->gsm->dlci[dlci->addr] = NULL;
2693 kfifo_free(&dlci->fifo);
2694 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
2695 dev_kfree_skb(dlci->skb);
2696 kfree(dlci);
2697}
2698
2699static inline void dlci_get(struct gsm_dlci *dlci)
2700{
2701 tty_port_get(&dlci->port);
2702}
2703
2704static inline void dlci_put(struct gsm_dlci *dlci)
2705{
2706 tty_port_put(&dlci->port);
2707}
2708
2709static void gsm_destroy_network(struct gsm_dlci *dlci);
2710
2711/**
2712 * gsm_dlci_release - release DLCI
2713 * @dlci: DLCI to destroy
2714 *
2715 * Release a DLCI. Actual free is deferred until either
2716 * mux is closed or tty is closed - whichever is last.
2717 *
2718 * Can sleep.
2719 */
2720static void gsm_dlci_release(struct gsm_dlci *dlci)
2721{
2722 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
2723 if (tty) {
2724 mutex_lock(&dlci->mutex);
2725 gsm_destroy_network(dlci);
2726 mutex_unlock(&dlci->mutex);
2727
2728 /* We cannot use tty_hangup() because in tty_kref_put() the tty
2729 * driver assumes that the hangup queue is free and reuses it to
2730 * queue release_one_tty() -> NULL pointer panic in
2731 * process_one_work().
2732 */
2733 tty_vhangup(tty);
2734
2735 tty_port_tty_set(&dlci->port, NULL);
2736 tty_kref_put(tty);
2737 }
2738 dlci->state = DLCI_CLOSED;
2739 dlci_put(dlci);
2740}
2741
2742/*
2743 * LAPBish link layer logic
2744 */
2745
2746/**
2747 * gsm_queue - a GSM frame is ready to process
2748 * @gsm: pointer to our gsm mux
2749 *
2750 * At this point in time a frame has arrived and been demangled from
2751 * the line encoding. All the differences between the encodings have
2752 * been handled below us and the frame is unpacked into the structures.
2753 * The fcs holds the header FCS but any data FCS must be added here.
2754 */
2755
2756static void gsm_queue(struct gsm_mux *gsm)
2757{
2758 struct gsm_dlci *dlci;
2759 u8 cr;
2760 int address;
2761
2762 if (gsm->fcs != GOOD_FCS) {
2763 gsm->bad_fcs++;
2764 if (debug & DBG_DATA)
2765 pr_debug("BAD FCS %02x\n", gsm->fcs);
2766 return;
2767 }
2768 address = gsm->address >> 1;
2769 if (address >= NUM_DLCI)
2770 goto invalid;
2771
2772 cr = gsm->address & 1; /* C/R bit */
2773 cr ^= gsm->initiator ? 0 : 1; /* Flip so 1 always means command */
2774
2775 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
2776
2777 dlci = gsm->dlci[address];
2778
2779 switch (gsm->control) {
2780 case SABM|PF:
2781 if (cr == 1) {
2782 gsm->open_error++;
2783 goto invalid;
2784 }
2785 if (dlci == NULL)
2786 dlci = gsm_dlci_alloc(gsm, address);
2787 if (dlci == NULL) {
2788 gsm->open_error++;
2789 return;
2790 }
2791 if (dlci->dead)
2792 gsm_response(gsm, address, DM|PF);
2793 else {
2794 gsm_response(gsm, address, UA|PF);
2795 gsm_dlci_open(dlci);
2796 }
2797 break;
2798 case DISC|PF:
2799 if (cr == 1)
2800 goto invalid;
2801 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
2802 gsm_response(gsm, address, DM|PF);
2803 return;
2804 }
2805 /* Real close complete */
2806 gsm_response(gsm, address, UA|PF);
2807 gsm_dlci_close(dlci);
2808 break;
2809 case UA|PF:
2810 if (cr == 0 || dlci == NULL)
2811 break;
2812 switch (dlci->state) {
2813 case DLCI_CLOSING:
2814 gsm_dlci_close(dlci);
2815 break;
2816 case DLCI_OPENING:
2817 gsm_dlci_open(dlci);
2818 break;
2819 default:
2820 pr_debug("%s: unhandled state: %d\n", __func__,
2821 dlci->state);
2822 break;
2823 }
2824 break;
2825 case DM: /* DM can be valid unsolicited */
2826 case DM|PF:
2827 if (cr)
2828 goto invalid;
2829 if (dlci == NULL)
2830 return;
2831 gsm_dlci_close(dlci);
2832 break;
2833 case UI:
2834 case UI|PF:
2835 case UIH:
2836 case UIH|PF:
2837 if (dlci == NULL || dlci->state != DLCI_OPEN) {
2838 gsm_response(gsm, address, DM|PF);
2839 return;
2840 }
2841 dlci->data(dlci, gsm->buf, gsm->len);
2842 break;
2843 default:
2844 goto invalid;
2845 }
2846 return;
2847invalid:
2848 gsm->malformed++;
2849 return;
2850}
2851
2852/**
2853 * gsm0_receive_state_check_and_fix - check and correct receive state
2854 * @gsm: gsm data for this ldisc instance
2855 *
2856 * Ensures that the current receive state is valid for basic option mode.
2857 */
2858
2859static void gsm0_receive_state_check_and_fix(struct gsm_mux *gsm)
2860{
2861 switch (gsm->state) {
2862 case GSM_SEARCH:
2863 case GSM0_ADDRESS:
2864 case GSM0_CONTROL:
2865 case GSM0_LEN0:
2866 case GSM0_LEN1:
2867 case GSM0_DATA:
2868 case GSM0_FCS:
2869 case GSM0_SSOF:
2870 break;
2871 default:
2872 gsm->state = GSM_SEARCH;
2873 break;
2874 }
2875}
2876
2877/**
2878 * gsm0_receive - perform processing for non-transparency
2879 * @gsm: gsm data for this ldisc instance
2880 * @c: character
2881 *
2882 * Receive bytes in gsm mode 0
2883 */
2884
2885static void gsm0_receive(struct gsm_mux *gsm, u8 c)
2886{
2887 unsigned int len;
2888
2889 gsm0_receive_state_check_and_fix(gsm);
2890 switch (gsm->state) {
2891 case GSM_SEARCH: /* SOF marker */
2892 if (c == GSM0_SOF) {
2893 gsm->state = GSM0_ADDRESS;
2894 gsm->address = 0;
2895 gsm->len = 0;
2896 gsm->fcs = INIT_FCS;
2897 }
2898 break;
2899 case GSM0_ADDRESS: /* Address EA */
2900 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2901 if (gsm_read_ea(&gsm->address, c))
2902 gsm->state = GSM0_CONTROL;
2903 break;
2904 case GSM0_CONTROL: /* Control Byte */
2905 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2906 gsm->control = c;
2907 gsm->state = GSM0_LEN0;
2908 break;
2909 case GSM0_LEN0: /* Length EA */
2910 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2911 if (gsm_read_ea(&gsm->len, c)) {
2912 if (gsm->len > gsm->mru) {
2913 gsm->bad_size++;
2914 gsm->state = GSM_SEARCH;
2915 break;
2916 }
2917 gsm->count = 0;
2918 if (!gsm->len)
2919 gsm->state = GSM0_FCS;
2920 else
2921 gsm->state = GSM0_DATA;
2922 break;
2923 }
2924 gsm->state = GSM0_LEN1;
2925 break;
2926 case GSM0_LEN1:
2927 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2928 len = c;
2929 gsm->len |= len << 7;
2930 if (gsm->len > gsm->mru) {
2931 gsm->bad_size++;
2932 gsm->state = GSM_SEARCH;
2933 break;
2934 }
2935 gsm->count = 0;
2936 if (!gsm->len)
2937 gsm->state = GSM0_FCS;
2938 else
2939 gsm->state = GSM0_DATA;
2940 break;
2941 case GSM0_DATA: /* Data */
2942 gsm->buf[gsm->count++] = c;
2943 if (gsm->count >= MAX_MRU) {
2944 gsm->bad_size++;
2945 gsm->state = GSM_SEARCH;
2946 } else if (gsm->count >= gsm->len) {
2947 /* Calculate final FCS for UI frames over all data */
2948 if ((gsm->control & ~PF) != UIH) {
2949 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
2950 gsm->count);
2951 }
2952 gsm->state = GSM0_FCS;
2953 }
2954 break;
2955 case GSM0_FCS: /* FCS follows the packet */
2956 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2957 gsm->state = GSM0_SSOF;
2958 break;
2959 case GSM0_SSOF:
2960 gsm->state = GSM_SEARCH;
2961 if (c == GSM0_SOF)
2962 gsm_queue(gsm);
2963 else
2964 gsm->bad_size++;
2965 break;
2966 default:
2967 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
2968 break;
2969 }
2970}
2971
2972/**
2973 * gsm1_receive_state_check_and_fix - check and correct receive state
2974 * @gsm: gsm data for this ldisc instance
2975 *
2976 * Ensures that the current receive state is valid for advanced option mode.
2977 */
2978
2979static void gsm1_receive_state_check_and_fix(struct gsm_mux *gsm)
2980{
2981 switch (gsm->state) {
2982 case GSM_SEARCH:
2983 case GSM1_START:
2984 case GSM1_ADDRESS:
2985 case GSM1_CONTROL:
2986 case GSM1_DATA:
2987 case GSM1_OVERRUN:
2988 break;
2989 default:
2990 gsm->state = GSM_SEARCH;
2991 break;
2992 }
2993}
2994
2995/**
2996 * gsm1_receive - perform processing for non-transparency
2997 * @gsm: gsm data for this ldisc instance
2998 * @c: character
2999 *
3000 * Receive bytes in mode 1 (Advanced option)
3001 */
3002
3003static void gsm1_receive(struct gsm_mux *gsm, u8 c)
3004{
3005 gsm1_receive_state_check_and_fix(gsm);
3006 /* handle XON/XOFF */
3007 if ((c & ISO_IEC_646_MASK) == XON) {
3008 gsm->constipated = true;
3009 return;
3010 } else if ((c & ISO_IEC_646_MASK) == XOFF) {
3011 gsm->constipated = false;
3012 /* Kick the link in case it is idling */
3013 gsmld_write_trigger(gsm);
3014 return;
3015 }
3016 if (c == GSM1_SOF) {
3017 /* EOF is only valid in frame if we have got to the data state */
3018 if (gsm->state == GSM1_DATA) {
3019 if (gsm->count < 1) {
3020 /* Missing FSC */
3021 gsm->malformed++;
3022 gsm->state = GSM1_START;
3023 return;
3024 }
3025 /* Remove the FCS from data */
3026 gsm->count--;
3027 if ((gsm->control & ~PF) != UIH) {
3028 /* Calculate final FCS for UI frames over all
3029 * data but FCS
3030 */
3031 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
3032 gsm->count);
3033 }
3034 /* Add the FCS itself to test against GOOD_FCS */
3035 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
3036 gsm->len = gsm->count;
3037 gsm_queue(gsm);
3038 gsm->state = GSM1_START;
3039 return;
3040 }
3041 /* Any partial frame was a runt so go back to start */
3042 if (gsm->state != GSM1_START) {
3043 if (gsm->state != GSM_SEARCH)
3044 gsm->malformed++;
3045 gsm->state = GSM1_START;
3046 }
3047 /* A SOF in GSM_START means we are still reading idling or
3048 framing bytes */
3049 return;
3050 }
3051
3052 if (c == GSM1_ESCAPE) {
3053 gsm->escape = true;
3054 return;
3055 }
3056
3057 /* Only an unescaped SOF gets us out of GSM search */
3058 if (gsm->state == GSM_SEARCH)
3059 return;
3060
3061 if (gsm->escape) {
3062 c ^= GSM1_ESCAPE_BITS;
3063 gsm->escape = false;
3064 }
3065 switch (gsm->state) {
3066 case GSM1_START: /* First byte after SOF */
3067 gsm->address = 0;
3068 gsm->state = GSM1_ADDRESS;
3069 gsm->fcs = INIT_FCS;
3070 fallthrough;
3071 case GSM1_ADDRESS: /* Address continuation */
3072 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
3073 if (gsm_read_ea(&gsm->address, c))
3074 gsm->state = GSM1_CONTROL;
3075 break;
3076 case GSM1_CONTROL: /* Control Byte */
3077 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
3078 gsm->control = c;
3079 gsm->count = 0;
3080 gsm->state = GSM1_DATA;
3081 break;
3082 case GSM1_DATA: /* Data */
3083 if (gsm->count > gsm->mru || gsm->count > MAX_MRU) { /* Allow one for the FCS */
3084 gsm->state = GSM1_OVERRUN;
3085 gsm->bad_size++;
3086 } else
3087 gsm->buf[gsm->count++] = c;
3088 break;
3089 case GSM1_OVERRUN: /* Over-long - eg a dropped SOF */
3090 break;
3091 default:
3092 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
3093 break;
3094 }
3095}
3096
3097/**
3098 * gsm_error - handle tty error
3099 * @gsm: ldisc data
3100 *
3101 * Handle an error in the receipt of data for a frame. Currently we just
3102 * go back to hunting for a SOF.
3103 *
3104 * FIXME: better diagnostics ?
3105 */
3106
3107static void gsm_error(struct gsm_mux *gsm)
3108{
3109 gsm->state = GSM_SEARCH;
3110 gsm->io_error++;
3111}
3112
3113/**
3114 * gsm_cleanup_mux - generic GSM protocol cleanup
3115 * @gsm: our mux
3116 * @disc: disconnect link?
3117 *
3118 * Clean up the bits of the mux which are the same for all framing
3119 * protocols. Remove the mux from the mux table, stop all the timers
3120 * and then shut down each device hanging up the channels as we go.
3121 */
3122
3123static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc)
3124{
3125 int i;
3126 struct gsm_dlci *dlci;
3127 struct gsm_msg *txq, *ntxq;
3128
3129 gsm->dead = true;
3130 mutex_lock(&gsm->mutex);
3131
3132 dlci = gsm->dlci[0];
3133 if (dlci) {
3134 if (disc && dlci->state != DLCI_CLOSED) {
3135 gsm_dlci_begin_close(dlci);
3136 wait_event(gsm->event, dlci->state == DLCI_CLOSED);
3137 }
3138 dlci->dead = true;
3139 }
3140
3141 /* Finish outstanding timers, making sure they are done */
3142 del_timer_sync(&gsm->kick_timer);
3143 del_timer_sync(&gsm->t2_timer);
3144 del_timer_sync(&gsm->ka_timer);
3145
3146 /* Finish writing to ldisc */
3147 flush_work(&gsm->tx_work);
3148
3149 /* Free up any link layer users and finally the control channel */
3150 if (gsm->has_devices) {
3151 gsm_unregister_devices(gsm_tty_driver, gsm->num);
3152 gsm->has_devices = false;
3153 }
3154 for (i = NUM_DLCI - 1; i >= 0; i--)
3155 if (gsm->dlci[i])
3156 gsm_dlci_release(gsm->dlci[i]);
3157 mutex_unlock(&gsm->mutex);
3158 /* Now wipe the queues */
3159 tty_ldisc_flush(gsm->tty);
3160 list_for_each_entry_safe(txq, ntxq, &gsm->tx_ctrl_list, list)
3161 kfree(txq);
3162 INIT_LIST_HEAD(&gsm->tx_ctrl_list);
3163 list_for_each_entry_safe(txq, ntxq, &gsm->tx_data_list, list)
3164 kfree(txq);
3165 INIT_LIST_HEAD(&gsm->tx_data_list);
3166}
3167
3168/**
3169 * gsm_activate_mux - generic GSM setup
3170 * @gsm: our mux
3171 *
3172 * Set up the bits of the mux which are the same for all framing
3173 * protocols. Add the mux to the mux table so it can be opened and
3174 * finally kick off connecting to DLCI 0 on the modem.
3175 */
3176
3177static int gsm_activate_mux(struct gsm_mux *gsm)
3178{
3179 struct gsm_dlci *dlci;
3180 int ret;
3181
3182 dlci = gsm_dlci_alloc(gsm, 0);
3183 if (dlci == NULL)
3184 return -ENOMEM;
3185
3186 if (gsm->encoding == GSM_BASIC_OPT)
3187 gsm->receive = gsm0_receive;
3188 else
3189 gsm->receive = gsm1_receive;
3190
3191 ret = gsm_register_devices(gsm_tty_driver, gsm->num);
3192 if (ret)
3193 return ret;
3194
3195 gsm->has_devices = true;
3196 gsm->dead = false; /* Tty opens are now permissible */
3197 return 0;
3198}
3199
3200/**
3201 * gsm_free_mux - free up a mux
3202 * @gsm: mux to free
3203 *
3204 * Dispose of allocated resources for a dead mux
3205 */
3206static void gsm_free_mux(struct gsm_mux *gsm)
3207{
3208 int i;
3209
3210 for (i = 0; i < MAX_MUX; i++) {
3211 if (gsm == gsm_mux[i]) {
3212 gsm_mux[i] = NULL;
3213 break;
3214 }
3215 }
3216 mutex_destroy(&gsm->mutex);
3217 kfree(gsm->txframe);
3218 kfree(gsm->buf);
3219 kfree(gsm);
3220}
3221
3222/**
3223 * gsm_free_muxr - free up a mux
3224 * @ref: kreference to the mux to free
3225 *
3226 * Dispose of allocated resources for a dead mux
3227 */
3228static void gsm_free_muxr(struct kref *ref)
3229{
3230 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
3231 gsm_free_mux(gsm);
3232}
3233
3234static inline void mux_get(struct gsm_mux *gsm)
3235{
3236 unsigned long flags;
3237
3238 spin_lock_irqsave(&gsm_mux_lock, flags);
3239 kref_get(&gsm->ref);
3240 spin_unlock_irqrestore(&gsm_mux_lock, flags);
3241}
3242
3243static inline void mux_put(struct gsm_mux *gsm)
3244{
3245 unsigned long flags;
3246
3247 spin_lock_irqsave(&gsm_mux_lock, flags);
3248 kref_put(&gsm->ref, gsm_free_muxr);
3249 spin_unlock_irqrestore(&gsm_mux_lock, flags);
3250}
3251
3252static inline unsigned int mux_num_to_base(struct gsm_mux *gsm)
3253{
3254 return gsm->num * NUM_DLCI;
3255}
3256
3257static inline unsigned int mux_line_to_num(unsigned int line)
3258{
3259 return line / NUM_DLCI;
3260}
3261
3262/**
3263 * gsm_alloc_mux - allocate a mux
3264 *
3265 * Creates a new mux ready for activation.
3266 */
3267
3268static struct gsm_mux *gsm_alloc_mux(void)
3269{
3270 int i;
3271 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
3272 if (gsm == NULL)
3273 return NULL;
3274 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
3275 if (gsm->buf == NULL) {
3276 kfree(gsm);
3277 return NULL;
3278 }
3279 gsm->txframe = kmalloc(2 * (MAX_MTU + PROT_OVERHEAD - 1), GFP_KERNEL);
3280 if (gsm->txframe == NULL) {
3281 kfree(gsm->buf);
3282 kfree(gsm);
3283 return NULL;
3284 }
3285 spin_lock_init(&gsm->lock);
3286 mutex_init(&gsm->mutex);
3287 kref_init(&gsm->ref);
3288 INIT_LIST_HEAD(&gsm->tx_ctrl_list);
3289 INIT_LIST_HEAD(&gsm->tx_data_list);
3290 timer_setup(&gsm->kick_timer, gsm_kick_timer, 0);
3291 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
3292 timer_setup(&gsm->ka_timer, gsm_control_keep_alive, 0);
3293 INIT_WORK(&gsm->tx_work, gsmld_write_task);
3294 init_waitqueue_head(&gsm->event);
3295 spin_lock_init(&gsm->control_lock);
3296 spin_lock_init(&gsm->tx_lock);
3297
3298 gsm->t1 = T1;
3299 gsm->t2 = T2;
3300 gsm->t3 = T3;
3301 gsm->n2 = N2;
3302 gsm->k = K;
3303 gsm->ftype = UIH;
3304 gsm->adaption = 1;
3305 gsm->encoding = GSM_ADV_OPT;
3306 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
3307 gsm->mtu = 64;
3308 gsm->dead = true; /* Avoid early tty opens */
3309 gsm->wait_config = false; /* Disabled */
3310 gsm->keep_alive = 0; /* Disabled */
3311
3312 /* Store the instance to the mux array or abort if no space is
3313 * available.
3314 */
3315 spin_lock(&gsm_mux_lock);
3316 for (i = 0; i < MAX_MUX; i++) {
3317 if (!gsm_mux[i]) {
3318 gsm_mux[i] = gsm;
3319 gsm->num = i;
3320 break;
3321 }
3322 }
3323 spin_unlock(&gsm_mux_lock);
3324 if (i == MAX_MUX) {
3325 mutex_destroy(&gsm->mutex);
3326 kfree(gsm->txframe);
3327 kfree(gsm->buf);
3328 kfree(gsm);
3329 return NULL;
3330 }
3331
3332 return gsm;
3333}
3334
3335static void gsm_copy_config_values(struct gsm_mux *gsm,
3336 struct gsm_config *c)
3337{
3338 memset(c, 0, sizeof(*c));
3339 c->adaption = gsm->adaption;
3340 c->encapsulation = gsm->encoding;
3341 c->initiator = gsm->initiator;
3342 c->t1 = gsm->t1;
3343 c->t2 = gsm->t2;
3344 c->t3 = gsm->t3;
3345 c->n2 = gsm->n2;
3346 if (gsm->ftype == UIH)
3347 c->i = 1;
3348 else
3349 c->i = 2;
3350 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i);
3351 c->mru = gsm->mru;
3352 c->mtu = gsm->mtu;
3353 c->k = gsm->k;
3354}
3355
3356static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
3357{
3358 int need_close = 0;
3359 int need_restart = 0;
3360
3361 /* Stuff we don't support yet - UI or I frame transport */
3362 if (c->adaption != 1 && c->adaption != 2)
3363 return -EOPNOTSUPP;
3364 /* Check the MRU/MTU range looks sane */
3365 if (c->mru < MIN_MTU || c->mtu < MIN_MTU)
3366 return -EINVAL;
3367 if (c->mru > MAX_MRU || c->mtu > MAX_MTU)
3368 return -EINVAL;
3369 if (c->t3 > MAX_T3)
3370 return -EINVAL;
3371 if (c->n2 > 255)
3372 return -EINVAL;
3373 if (c->encapsulation > 1) /* Basic, advanced, no I */
3374 return -EINVAL;
3375 if (c->initiator > 1)
3376 return -EINVAL;
3377 if (c->k > MAX_WINDOW_SIZE)
3378 return -EINVAL;
3379 if (c->i == 0 || c->i > 2) /* UIH and UI only */
3380 return -EINVAL;
3381 /*
3382 * See what is needed for reconfiguration
3383 */
3384
3385 /* Timing fields */
3386 if (c->t1 != 0 && c->t1 != gsm->t1)
3387 need_restart = 1;
3388 if (c->t2 != 0 && c->t2 != gsm->t2)
3389 need_restart = 1;
3390 if (c->encapsulation != gsm->encoding)
3391 need_restart = 1;
3392 if (c->adaption != gsm->adaption)
3393 need_restart = 1;
3394 /* Requires care */
3395 if (c->initiator != gsm->initiator)
3396 need_close = 1;
3397 if (c->mru != gsm->mru)
3398 need_restart = 1;
3399 if (c->mtu != gsm->mtu)
3400 need_restart = 1;
3401
3402 /*
3403 * Close down what is needed, restart and initiate the new
3404 * configuration. On the first time there is no DLCI[0]
3405 * and closing or cleaning up is not necessary.
3406 */
3407 if (need_close || need_restart)
3408 gsm_cleanup_mux(gsm, true);
3409
3410 gsm->initiator = c->initiator;
3411 gsm->mru = c->mru;
3412 gsm->mtu = c->mtu;
3413 gsm->encoding = c->encapsulation ? GSM_ADV_OPT : GSM_BASIC_OPT;
3414 gsm->adaption = c->adaption;
3415 gsm->n2 = c->n2;
3416
3417 if (c->i == 1)
3418 gsm->ftype = UIH;
3419 else if (c->i == 2)
3420 gsm->ftype = UI;
3421
3422 if (c->t1)
3423 gsm->t1 = c->t1;
3424 if (c->t2)
3425 gsm->t2 = c->t2;
3426 if (c->t3)
3427 gsm->t3 = c->t3;
3428 if (c->k)
3429 gsm->k = c->k;
3430
3431 /*
3432 * FIXME: We need to separate activation/deactivation from adding
3433 * and removing from the mux array
3434 */
3435 if (gsm->dead) {
3436 int ret = gsm_activate_mux(gsm);
3437 if (ret)
3438 return ret;
3439 if (gsm->initiator)
3440 gsm_dlci_begin_open(gsm->dlci[0]);
3441 }
3442 return 0;
3443}
3444
3445static void gsm_copy_config_ext_values(struct gsm_mux *gsm,
3446 struct gsm_config_ext *ce)
3447{
3448 memset(ce, 0, sizeof(*ce));
3449 ce->wait_config = gsm->wait_config ? 1 : 0;
3450 ce->keep_alive = gsm->keep_alive;
3451}
3452
3453static int gsm_config_ext(struct gsm_mux *gsm, struct gsm_config_ext *ce)
3454{
3455 bool need_restart = false;
3456 unsigned int i;
3457
3458 /*
3459 * Check that userspace doesn't put stuff in here to prevent breakages
3460 * in the future.
3461 */
3462 for (i = 0; i < ARRAY_SIZE(ce->reserved); i++)
3463 if (ce->reserved[i])
3464 return -EINVAL;
3465 if (ce->flags & ~GSM_FL_RESTART)
3466 return -EINVAL;
3467
3468 /* Requires care */
3469 if (ce->flags & GSM_FL_RESTART)
3470 need_restart = true;
3471
3472 /*
3473 * Close down what is needed, restart and initiate the new
3474 * configuration. On the first time there is no DLCI[0]
3475 * and closing or cleaning up is not necessary.
3476 */
3477 if (need_restart)
3478 gsm_cleanup_mux(gsm, true);
3479
3480 /*
3481 * Setup the new configuration values
3482 */
3483 gsm->wait_config = ce->wait_config ? true : false;
3484 gsm->keep_alive = ce->keep_alive;
3485
3486 if (gsm->dead) {
3487 int ret = gsm_activate_mux(gsm);
3488 if (ret)
3489 return ret;
3490 if (gsm->initiator)
3491 gsm_dlci_begin_open(gsm->dlci[0]);
3492 }
3493
3494 return 0;
3495}
3496
3497/**
3498 * gsmld_output - write to link
3499 * @gsm: our mux
3500 * @data: bytes to output
3501 * @len: size
3502 *
3503 * Write a block of data from the GSM mux to the data channel. This
3504 * will eventually be serialized from above but at the moment isn't.
3505 */
3506
3507static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
3508{
3509 if (tty_write_room(gsm->tty) < len) {
3510 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
3511 return -ENOSPC;
3512 }
3513 if (debug & DBG_DATA)
3514 gsm_hex_dump_bytes(__func__, data, len);
3515 return gsm->tty->ops->write(gsm->tty, data, len);
3516}
3517
3518
3519/**
3520 * gsmld_write_trigger - schedule ldisc write task
3521 * @gsm: our mux
3522 */
3523static void gsmld_write_trigger(struct gsm_mux *gsm)
3524{
3525 if (!gsm || !gsm->dlci[0] || gsm->dlci[0]->dead)
3526 return;
3527 schedule_work(&gsm->tx_work);
3528}
3529
3530
3531/**
3532 * gsmld_write_task - ldisc write task
3533 * @work: our tx write work
3534 *
3535 * Writes out data to the ldisc if possible. We are doing this here to
3536 * avoid dead-locking. This returns if no space or data is left for output.
3537 */
3538static void gsmld_write_task(struct work_struct *work)
3539{
3540 struct gsm_mux *gsm = container_of(work, struct gsm_mux, tx_work);
3541 unsigned long flags;
3542 int i, ret;
3543
3544 /* All outstanding control channel and control messages and one data
3545 * frame is sent.
3546 */
3547 ret = -ENODEV;
3548 spin_lock_irqsave(&gsm->tx_lock, flags);
3549 if (gsm->tty)
3550 ret = gsm_data_kick(gsm);
3551 spin_unlock_irqrestore(&gsm->tx_lock, flags);
3552
3553 if (ret >= 0)
3554 for (i = 0; i < NUM_DLCI; i++)
3555 if (gsm->dlci[i])
3556 tty_port_tty_wakeup(&gsm->dlci[i]->port);
3557}
3558
3559/**
3560 * gsmld_attach_gsm - mode set up
3561 * @tty: our tty structure
3562 * @gsm: our mux
3563 *
3564 * Set up the MUX for basic mode and commence connecting to the
3565 * modem. Currently called from the line discipline set up but
3566 * will need moving to an ioctl path.
3567 */
3568
3569static void gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
3570{
3571 gsm->tty = tty_kref_get(tty);
3572 /* Turn off tty XON/XOFF handling to handle it explicitly. */
3573 gsm->old_c_iflag = tty->termios.c_iflag;
3574 tty->termios.c_iflag &= (IXON | IXOFF);
3575}
3576
3577/**
3578 * gsmld_detach_gsm - stop doing 0710 mux
3579 * @tty: tty attached to the mux
3580 * @gsm: mux
3581 *
3582 * Shutdown and then clean up the resources used by the line discipline
3583 */
3584
3585static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
3586{
3587 WARN_ON(tty != gsm->tty);
3588 /* Restore tty XON/XOFF handling. */
3589 gsm->tty->termios.c_iflag = gsm->old_c_iflag;
3590 tty_kref_put(gsm->tty);
3591 gsm->tty = NULL;
3592}
3593
3594static void gsmld_receive_buf(struct tty_struct *tty, const u8 *cp,
3595 const u8 *fp, size_t count)
3596{
3597 struct gsm_mux *gsm = tty->disc_data;
3598 u8 flags = TTY_NORMAL;
3599
3600 if (debug & DBG_DATA)
3601 gsm_hex_dump_bytes(__func__, cp, count);
3602
3603 for (; count; count--, cp++) {
3604 if (fp)
3605 flags = *fp++;
3606 switch (flags) {
3607 case TTY_NORMAL:
3608 if (gsm->receive)
3609 gsm->receive(gsm, *cp);
3610 break;
3611 case TTY_OVERRUN:
3612 case TTY_BREAK:
3613 case TTY_PARITY:
3614 case TTY_FRAME:
3615 gsm_error(gsm);
3616 break;
3617 default:
3618 WARN_ONCE(1, "%s: unknown flag %d\n",
3619 tty_name(tty), flags);
3620 break;
3621 }
3622 }
3623 /* FASYNC if needed ? */
3624 /* If clogged call tty_throttle(tty); */
3625}
3626
3627/**
3628 * gsmld_flush_buffer - clean input queue
3629 * @tty: terminal device
3630 *
3631 * Flush the input buffer. Called when the line discipline is
3632 * being closed, when the tty layer wants the buffer flushed (eg
3633 * at hangup).
3634 */
3635
3636static void gsmld_flush_buffer(struct tty_struct *tty)
3637{
3638}
3639
3640/**
3641 * gsmld_close - close the ldisc for this tty
3642 * @tty: device
3643 *
3644 * Called from the terminal layer when this line discipline is
3645 * being shut down, either because of a close or becsuse of a
3646 * discipline change. The function will not be called while other
3647 * ldisc methods are in progress.
3648 */
3649
3650static void gsmld_close(struct tty_struct *tty)
3651{
3652 struct gsm_mux *gsm = tty->disc_data;
3653
3654 /* The ldisc locks and closes the port before calling our close. This
3655 * means we have no way to do a proper disconnect. We will not bother
3656 * to do one.
3657 */
3658 gsm_cleanup_mux(gsm, false);
3659
3660 gsmld_detach_gsm(tty, gsm);
3661
3662 gsmld_flush_buffer(tty);
3663 /* Do other clean up here */
3664 mux_put(gsm);
3665}
3666
3667/**
3668 * gsmld_open - open an ldisc
3669 * @tty: terminal to open
3670 *
3671 * Called when this line discipline is being attached to the
3672 * terminal device. Can sleep. Called serialized so that no
3673 * other events will occur in parallel. No further open will occur
3674 * until a close.
3675 */
3676
3677static int gsmld_open(struct tty_struct *tty)
3678{
3679 struct gsm_mux *gsm;
3680
3681 if (!capable(CAP_NET_ADMIN))
3682 return -EPERM;
3683
3684 if (tty->ops->write == NULL)
3685 return -EINVAL;
3686
3687 /* Attach our ldisc data */
3688 gsm = gsm_alloc_mux();
3689 if (gsm == NULL)
3690 return -ENOMEM;
3691
3692 tty->disc_data = gsm;
3693 tty->receive_room = 65536;
3694
3695 /* Attach the initial passive connection */
3696 gsmld_attach_gsm(tty, gsm);
3697
3698 /* The mux will not be activated yet, we wait for correct
3699 * configuration first.
3700 */
3701 if (gsm->encoding == GSM_BASIC_OPT)
3702 gsm->receive = gsm0_receive;
3703 else
3704 gsm->receive = gsm1_receive;
3705
3706 return 0;
3707}
3708
3709/**
3710 * gsmld_write_wakeup - asynchronous I/O notifier
3711 * @tty: tty device
3712 *
3713 * Required for the ptys, serial driver etc. since processes
3714 * that attach themselves to the master and rely on ASYNC
3715 * IO must be woken up
3716 */
3717
3718static void gsmld_write_wakeup(struct tty_struct *tty)
3719{
3720 struct gsm_mux *gsm = tty->disc_data;
3721
3722 /* Queue poll */
3723 gsmld_write_trigger(gsm);
3724}
3725
3726/**
3727 * gsmld_read - read function for tty
3728 * @tty: tty device
3729 * @file: file object
3730 * @buf: userspace buffer pointer
3731 * @nr: size of I/O
3732 * @cookie: unused
3733 * @offset: unused
3734 *
3735 * Perform reads for the line discipline. We are guaranteed that the
3736 * line discipline will not be closed under us but we may get multiple
3737 * parallel readers and must handle this ourselves. We may also get
3738 * a hangup. Always called in user context, may sleep.
3739 *
3740 * This code must be sure never to sleep through a hangup.
3741 */
3742
3743static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, u8 *buf,
3744 size_t nr, void **cookie, unsigned long offset)
3745{
3746 return -EOPNOTSUPP;
3747}
3748
3749/**
3750 * gsmld_write - write function for tty
3751 * @tty: tty device
3752 * @file: file object
3753 * @buf: userspace buffer pointer
3754 * @nr: size of I/O
3755 *
3756 * Called when the owner of the device wants to send a frame
3757 * itself (or some other control data). The data is transferred
3758 * as-is and must be properly framed and checksummed as appropriate
3759 * by userspace. Frames are either sent whole or not at all as this
3760 * avoids pain user side.
3761 */
3762
3763static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
3764 const u8 *buf, size_t nr)
3765{
3766 struct gsm_mux *gsm = tty->disc_data;
3767 unsigned long flags;
3768 size_t space;
3769 int ret;
3770
3771 if (!gsm)
3772 return -ENODEV;
3773
3774 ret = -ENOBUFS;
3775 spin_lock_irqsave(&gsm->tx_lock, flags);
3776 space = tty_write_room(tty);
3777 if (space >= nr)
3778 ret = tty->ops->write(tty, buf, nr);
3779 else
3780 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
3781 spin_unlock_irqrestore(&gsm->tx_lock, flags);
3782
3783 return ret;
3784}
3785
3786/**
3787 * gsmld_poll - poll method for N_GSM0710
3788 * @tty: terminal device
3789 * @file: file accessing it
3790 * @wait: poll table
3791 *
3792 * Called when the line discipline is asked to poll() for data or
3793 * for special events. This code is not serialized with respect to
3794 * other events save open/close.
3795 *
3796 * This code must be sure never to sleep through a hangup.
3797 * Called without the kernel lock held - fine
3798 */
3799
3800static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
3801 poll_table *wait)
3802{
3803 __poll_t mask = 0;
3804 struct gsm_mux *gsm = tty->disc_data;
3805
3806 poll_wait(file, &tty->read_wait, wait);
3807 poll_wait(file, &tty->write_wait, wait);
3808
3809 if (gsm->dead)
3810 mask |= EPOLLHUP;
3811 if (tty_hung_up_p(file))
3812 mask |= EPOLLHUP;
3813 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
3814 mask |= EPOLLHUP;
3815 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
3816 mask |= EPOLLOUT | EPOLLWRNORM;
3817 return mask;
3818}
3819
3820static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd,
3821 unsigned long arg)
3822{
3823 struct gsm_config c;
3824 struct gsm_config_ext ce;
3825 struct gsm_dlci_config dc;
3826 struct gsm_mux *gsm = tty->disc_data;
3827 unsigned int base, addr;
3828 struct gsm_dlci *dlci;
3829
3830 switch (cmd) {
3831 case GSMIOC_GETCONF:
3832 gsm_copy_config_values(gsm, &c);
3833 if (copy_to_user((void __user *)arg, &c, sizeof(c)))
3834 return -EFAULT;
3835 return 0;
3836 case GSMIOC_SETCONF:
3837 if (copy_from_user(&c, (void __user *)arg, sizeof(c)))
3838 return -EFAULT;
3839 return gsm_config(gsm, &c);
3840 case GSMIOC_GETFIRST:
3841 base = mux_num_to_base(gsm);
3842 return put_user(base + 1, (__u32 __user *)arg);
3843 case GSMIOC_GETCONF_EXT:
3844 gsm_copy_config_ext_values(gsm, &ce);
3845 if (copy_to_user((void __user *)arg, &ce, sizeof(ce)))
3846 return -EFAULT;
3847 return 0;
3848 case GSMIOC_SETCONF_EXT:
3849 if (copy_from_user(&ce, (void __user *)arg, sizeof(ce)))
3850 return -EFAULT;
3851 return gsm_config_ext(gsm, &ce);
3852 case GSMIOC_GETCONF_DLCI:
3853 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc)))
3854 return -EFAULT;
3855 if (dc.channel == 0 || dc.channel >= NUM_DLCI)
3856 return -EINVAL;
3857 addr = array_index_nospec(dc.channel, NUM_DLCI);
3858 dlci = gsm->dlci[addr];
3859 if (!dlci) {
3860 dlci = gsm_dlci_alloc(gsm, addr);
3861 if (!dlci)
3862 return -ENOMEM;
3863 }
3864 gsm_dlci_copy_config_values(dlci, &dc);
3865 if (copy_to_user((void __user *)arg, &dc, sizeof(dc)))
3866 return -EFAULT;
3867 return 0;
3868 case GSMIOC_SETCONF_DLCI:
3869 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc)))
3870 return -EFAULT;
3871 if (dc.channel == 0 || dc.channel >= NUM_DLCI)
3872 return -EINVAL;
3873 addr = array_index_nospec(dc.channel, NUM_DLCI);
3874 dlci = gsm->dlci[addr];
3875 if (!dlci) {
3876 dlci = gsm_dlci_alloc(gsm, addr);
3877 if (!dlci)
3878 return -ENOMEM;
3879 }
3880 return gsm_dlci_config(dlci, &dc, 0);
3881 default:
3882 return n_tty_ioctl_helper(tty, cmd, arg);
3883 }
3884}
3885
3886/*
3887 * Network interface
3888 *
3889 */
3890
3891static int gsm_mux_net_open(struct net_device *net)
3892{
3893 pr_debug("%s called\n", __func__);
3894 netif_start_queue(net);
3895 return 0;
3896}
3897
3898static int gsm_mux_net_close(struct net_device *net)
3899{
3900 netif_stop_queue(net);
3901 return 0;
3902}
3903
3904static void dlci_net_free(struct gsm_dlci *dlci)
3905{
3906 if (!dlci->net) {
3907 WARN_ON(1);
3908 return;
3909 }
3910 dlci->adaption = dlci->prev_adaption;
3911 dlci->data = dlci->prev_data;
3912 free_netdev(dlci->net);
3913 dlci->net = NULL;
3914}
3915static void net_free(struct kref *ref)
3916{
3917 struct gsm_mux_net *mux_net;
3918 struct gsm_dlci *dlci;
3919
3920 mux_net = container_of(ref, struct gsm_mux_net, ref);
3921 dlci = mux_net->dlci;
3922
3923 if (dlci->net) {
3924 unregister_netdev(dlci->net);
3925 dlci_net_free(dlci);
3926 }
3927}
3928
3929static inline void muxnet_get(struct gsm_mux_net *mux_net)
3930{
3931 kref_get(&mux_net->ref);
3932}
3933
3934static inline void muxnet_put(struct gsm_mux_net *mux_net)
3935{
3936 kref_put(&mux_net->ref, net_free);
3937}
3938
3939static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
3940 struct net_device *net)
3941{
3942 struct gsm_mux_net *mux_net = netdev_priv(net);
3943 struct gsm_dlci *dlci = mux_net->dlci;
3944 muxnet_get(mux_net);
3945
3946 skb_queue_head(&dlci->skb_list, skb);
3947 net->stats.tx_packets++;
3948 net->stats.tx_bytes += skb->len;
3949 gsm_dlci_data_kick(dlci);
3950 /* And tell the kernel when the last transmit started. */
3951 netif_trans_update(net);
3952 muxnet_put(mux_net);
3953 return NETDEV_TX_OK;
3954}
3955
3956/* called when a packet did not ack after watchdogtimeout */
3957static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue)
3958{
3959 /* Tell syslog we are hosed. */
3960 dev_dbg(&net->dev, "Tx timed out.\n");
3961
3962 /* Update statistics */
3963 net->stats.tx_errors++;
3964}
3965
3966static void gsm_mux_rx_netchar(struct gsm_dlci *dlci, const u8 *in_buf, int size)
3967{
3968 struct net_device *net = dlci->net;
3969 struct sk_buff *skb;
3970 struct gsm_mux_net *mux_net = netdev_priv(net);
3971 muxnet_get(mux_net);
3972
3973 /* Allocate an sk_buff */
3974 skb = dev_alloc_skb(size + NET_IP_ALIGN);
3975 if (!skb) {
3976 /* We got no receive buffer. */
3977 net->stats.rx_dropped++;
3978 muxnet_put(mux_net);
3979 return;
3980 }
3981 skb_reserve(skb, NET_IP_ALIGN);
3982 skb_put_data(skb, in_buf, size);
3983
3984 skb->dev = net;
3985 skb->protocol = htons(ETH_P_IP);
3986
3987 /* Ship it off to the kernel */
3988 netif_rx(skb);
3989
3990 /* update out statistics */
3991 net->stats.rx_packets++;
3992 net->stats.rx_bytes += size;
3993 muxnet_put(mux_net);
3994 return;
3995}
3996
3997static void gsm_mux_net_init(struct net_device *net)
3998{
3999 static const struct net_device_ops gsm_netdev_ops = {
4000 .ndo_open = gsm_mux_net_open,
4001 .ndo_stop = gsm_mux_net_close,
4002 .ndo_start_xmit = gsm_mux_net_start_xmit,
4003 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
4004 };
4005
4006 net->netdev_ops = &gsm_netdev_ops;
4007
4008 /* fill in the other fields */
4009 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
4010 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
4011 net->type = ARPHRD_NONE;
4012 net->tx_queue_len = 10;
4013}
4014
4015
4016/* caller holds the dlci mutex */
4017static void gsm_destroy_network(struct gsm_dlci *dlci)
4018{
4019 struct gsm_mux_net *mux_net;
4020
4021 pr_debug("destroy network interface\n");
4022 if (!dlci->net)
4023 return;
4024 mux_net = netdev_priv(dlci->net);
4025 muxnet_put(mux_net);
4026}
4027
4028
4029/* caller holds the dlci mutex */
4030static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
4031{
4032 char *netname;
4033 int retval = 0;
4034 struct net_device *net;
4035 struct gsm_mux_net *mux_net;
4036
4037 if (!capable(CAP_NET_ADMIN))
4038 return -EPERM;
4039
4040 /* Already in a non tty mode */
4041 if (dlci->adaption > 2)
4042 return -EBUSY;
4043
4044 if (nc->protocol != htons(ETH_P_IP))
4045 return -EPROTONOSUPPORT;
4046
4047 if (nc->adaption != 3 && nc->adaption != 4)
4048 return -EPROTONOSUPPORT;
4049
4050 pr_debug("create network interface\n");
4051
4052 netname = "gsm%d";
4053 if (nc->if_name[0] != '\0')
4054 netname = nc->if_name;
4055 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
4056 NET_NAME_UNKNOWN, gsm_mux_net_init);
4057 if (!net) {
4058 pr_err("alloc_netdev failed\n");
4059 return -ENOMEM;
4060 }
4061 net->mtu = dlci->mtu;
4062 net->min_mtu = MIN_MTU;
4063 net->max_mtu = dlci->mtu;
4064 mux_net = netdev_priv(net);
4065 mux_net->dlci = dlci;
4066 kref_init(&mux_net->ref);
4067 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
4068
4069 /* reconfigure dlci for network */
4070 dlci->prev_adaption = dlci->adaption;
4071 dlci->prev_data = dlci->data;
4072 dlci->adaption = nc->adaption;
4073 dlci->data = gsm_mux_rx_netchar;
4074 dlci->net = net;
4075
4076 pr_debug("register netdev\n");
4077 retval = register_netdev(net);
4078 if (retval) {
4079 pr_err("network register fail %d\n", retval);
4080 dlci_net_free(dlci);
4081 return retval;
4082 }
4083 return net->ifindex; /* return network index */
4084}
4085
4086/* Line discipline for real tty */
4087static struct tty_ldisc_ops tty_ldisc_packet = {
4088 .owner = THIS_MODULE,
4089 .num = N_GSM0710,
4090 .name = "n_gsm",
4091 .open = gsmld_open,
4092 .close = gsmld_close,
4093 .flush_buffer = gsmld_flush_buffer,
4094 .read = gsmld_read,
4095 .write = gsmld_write,
4096 .ioctl = gsmld_ioctl,
4097 .poll = gsmld_poll,
4098 .receive_buf = gsmld_receive_buf,
4099 .write_wakeup = gsmld_write_wakeup
4100};
4101
4102/*
4103 * Virtual tty side
4104 */
4105
4106/**
4107 * gsm_modem_upd_via_data - send modem bits via convergence layer
4108 * @dlci: channel
4109 * @brk: break signal
4110 *
4111 * Send an empty frame to signal mobile state changes and to transmit the
4112 * break signal for adaption 2.
4113 */
4114
4115static void gsm_modem_upd_via_data(struct gsm_dlci *dlci, u8 brk)
4116{
4117 struct gsm_mux *gsm = dlci->gsm;
4118 unsigned long flags;
4119
4120 if (dlci->state != DLCI_OPEN || dlci->adaption != 2)
4121 return;
4122
4123 spin_lock_irqsave(&gsm->tx_lock, flags);
4124 gsm_dlci_modem_output(gsm, dlci, brk);
4125 spin_unlock_irqrestore(&gsm->tx_lock, flags);
4126}
4127
4128/**
4129 * gsm_modem_upd_via_msc - send modem bits via control frame
4130 * @dlci: channel
4131 * @brk: break signal
4132 */
4133
4134static int gsm_modem_upd_via_msc(struct gsm_dlci *dlci, u8 brk)
4135{
4136 u8 modembits[3];
4137 struct gsm_control *ctrl;
4138 int len = 2;
4139
4140 if (dlci->gsm->encoding != GSM_BASIC_OPT)
4141 return 0;
4142
4143 modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */
4144 if (!brk) {
4145 modembits[1] = (gsm_encode_modem(dlci) << 1) | EA;
4146 } else {
4147 modembits[1] = gsm_encode_modem(dlci) << 1;
4148 modembits[2] = (brk << 4) | 2 | EA; /* Length, Break, EA */
4149 len++;
4150 }
4151 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len);
4152 if (ctrl == NULL)
4153 return -ENOMEM;
4154 return gsm_control_wait(dlci->gsm, ctrl);
4155}
4156
4157/**
4158 * gsm_modem_update - send modem status line state
4159 * @dlci: channel
4160 * @brk: break signal
4161 */
4162
4163static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk)
4164{
4165 if (dlci->gsm->dead)
4166 return -EL2HLT;
4167 if (dlci->adaption == 2) {
4168 /* Send convergence layer type 2 empty data frame. */
4169 gsm_modem_upd_via_data(dlci, brk);
4170 return 0;
4171 } else if (dlci->gsm->encoding == GSM_BASIC_OPT) {
4172 /* Send as MSC control message. */
4173 return gsm_modem_upd_via_msc(dlci, brk);
4174 }
4175
4176 /* Modem status lines are not supported. */
4177 return -EPROTONOSUPPORT;
4178}
4179
4180/**
4181 * gsm_wait_modem_change - wait for modem status line change
4182 * @dlci: channel
4183 * @mask: modem status line bits
4184 *
4185 * The function returns if:
4186 * - any given modem status line bit changed
4187 * - the wait event function got interrupted (e.g. by a signal)
4188 * - the underlying DLCI was closed
4189 * - the underlying ldisc device was removed
4190 */
4191static int gsm_wait_modem_change(struct gsm_dlci *dlci, u32 mask)
4192{
4193 struct gsm_mux *gsm = dlci->gsm;
4194 u32 old = dlci->modem_rx;
4195 int ret;
4196
4197 ret = wait_event_interruptible(gsm->event, gsm->dead ||
4198 dlci->state != DLCI_OPEN ||
4199 (old ^ dlci->modem_rx) & mask);
4200 if (gsm->dead)
4201 return -ENODEV;
4202 if (dlci->state != DLCI_OPEN)
4203 return -EL2NSYNC;
4204 return ret;
4205}
4206
4207static bool gsm_carrier_raised(struct tty_port *port)
4208{
4209 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
4210 struct gsm_mux *gsm = dlci->gsm;
4211
4212 /* Not yet open so no carrier info */
4213 if (dlci->state != DLCI_OPEN)
4214 return false;
4215 if (debug & DBG_CD_ON)
4216 return true;
4217
4218 /*
4219 * Basic mode with control channel in ADM mode may not respond
4220 * to CMD_MSC at all and modem_rx is empty.
4221 */
4222 if (gsm->encoding == GSM_BASIC_OPT &&
4223 gsm->dlci[0]->mode == DLCI_MODE_ADM && !dlci->modem_rx)
4224 return true;
4225
4226 return dlci->modem_rx & TIOCM_CD;
4227}
4228
4229static void gsm_dtr_rts(struct tty_port *port, bool active)
4230{
4231 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
4232 unsigned int modem_tx = dlci->modem_tx;
4233 if (active)
4234 modem_tx |= TIOCM_DTR | TIOCM_RTS;
4235 else
4236 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
4237 if (modem_tx != dlci->modem_tx) {
4238 dlci->modem_tx = modem_tx;
4239 gsm_modem_update(dlci, 0);
4240 }
4241}
4242
4243static const struct tty_port_operations gsm_port_ops = {
4244 .carrier_raised = gsm_carrier_raised,
4245 .dtr_rts = gsm_dtr_rts,
4246 .destruct = gsm_dlci_free,
4247};
4248
4249static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
4250{
4251 struct gsm_mux *gsm;
4252 struct gsm_dlci *dlci;
4253 unsigned int line = tty->index;
4254 unsigned int mux = mux_line_to_num(line);
4255 bool alloc = false;
4256 int ret;
4257
4258 line = line & 0x3F;
4259
4260 if (mux >= MAX_MUX)
4261 return -ENXIO;
4262 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
4263 if (gsm_mux[mux] == NULL)
4264 return -EUNATCH;
4265 if (line == 0 || line > 61) /* 62/63 reserved */
4266 return -ECHRNG;
4267 gsm = gsm_mux[mux];
4268 if (gsm->dead)
4269 return -EL2HLT;
4270 /* If DLCI 0 is not yet fully open return an error.
4271 This is ok from a locking
4272 perspective as we don't have to worry about this
4273 if DLCI0 is lost */
4274 mutex_lock(&gsm->mutex);
4275 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
4276 mutex_unlock(&gsm->mutex);
4277 return -EL2NSYNC;
4278 }
4279 dlci = gsm->dlci[line];
4280 if (dlci == NULL) {
4281 alloc = true;
4282 dlci = gsm_dlci_alloc(gsm, line);
4283 }
4284 if (dlci == NULL) {
4285 mutex_unlock(&gsm->mutex);
4286 return -ENOMEM;
4287 }
4288 ret = tty_port_install(&dlci->port, driver, tty);
4289 if (ret) {
4290 if (alloc)
4291 dlci_put(dlci);
4292 mutex_unlock(&gsm->mutex);
4293 return ret;
4294 }
4295
4296 dlci_get(dlci);
4297 dlci_get(gsm->dlci[0]);
4298 mux_get(gsm);
4299 tty->driver_data = dlci;
4300 mutex_unlock(&gsm->mutex);
4301
4302 return 0;
4303}
4304
4305static int gsmtty_open(struct tty_struct *tty, struct file *filp)
4306{
4307 struct gsm_dlci *dlci = tty->driver_data;
4308 struct tty_port *port = &dlci->port;
4309
4310 port->count++;
4311 tty_port_tty_set(port, tty);
4312
4313 dlci->modem_rx = 0;
4314 /* We could in theory open and close before we wait - eg if we get
4315 a DM straight back. This is ok as that will have caused a hangup */
4316 tty_port_set_initialized(port, true);
4317 /* Start sending off SABM messages */
4318 if (!dlci->gsm->wait_config) {
4319 /* Start sending off SABM messages */
4320 if (dlci->gsm->initiator)
4321 gsm_dlci_begin_open(dlci);
4322 else
4323 gsm_dlci_set_opening(dlci);
4324 } else {
4325 gsm_dlci_set_wait_config(dlci);
4326 }
4327 /* And wait for virtual carrier */
4328 return tty_port_block_til_ready(port, tty, filp);
4329}
4330
4331static void gsmtty_close(struct tty_struct *tty, struct file *filp)
4332{
4333 struct gsm_dlci *dlci = tty->driver_data;
4334
4335 if (dlci == NULL)
4336 return;
4337 if (dlci->state == DLCI_CLOSED)
4338 return;
4339 mutex_lock(&dlci->mutex);
4340 gsm_destroy_network(dlci);
4341 mutex_unlock(&dlci->mutex);
4342 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
4343 return;
4344 gsm_dlci_begin_close(dlci);
4345 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
4346 tty_port_lower_dtr_rts(&dlci->port);
4347 tty_port_close_end(&dlci->port, tty);
4348 tty_port_tty_set(&dlci->port, NULL);
4349 return;
4350}
4351
4352static void gsmtty_hangup(struct tty_struct *tty)
4353{
4354 struct gsm_dlci *dlci = tty->driver_data;
4355 if (dlci->state == DLCI_CLOSED)
4356 return;
4357 tty_port_hangup(&dlci->port);
4358 gsm_dlci_begin_close(dlci);
4359}
4360
4361static ssize_t gsmtty_write(struct tty_struct *tty, const u8 *buf, size_t len)
4362{
4363 int sent;
4364 struct gsm_dlci *dlci = tty->driver_data;
4365 if (dlci->state == DLCI_CLOSED)
4366 return -EINVAL;
4367 /* Stuff the bytes into the fifo queue */
4368 sent = kfifo_in_locked(&dlci->fifo, buf, len, &dlci->lock);
4369 /* Need to kick the channel */
4370 gsm_dlci_data_kick(dlci);
4371 return sent;
4372}
4373
4374static unsigned int gsmtty_write_room(struct tty_struct *tty)
4375{
4376 struct gsm_dlci *dlci = tty->driver_data;
4377 if (dlci->state == DLCI_CLOSED)
4378 return 0;
4379 return kfifo_avail(&dlci->fifo);
4380}
4381
4382static unsigned int gsmtty_chars_in_buffer(struct tty_struct *tty)
4383{
4384 struct gsm_dlci *dlci = tty->driver_data;
4385 if (dlci->state == DLCI_CLOSED)
4386 return 0;
4387 return kfifo_len(&dlci->fifo);
4388}
4389
4390static void gsmtty_flush_buffer(struct tty_struct *tty)
4391{
4392 struct gsm_dlci *dlci = tty->driver_data;
4393 unsigned long flags;
4394
4395 if (dlci->state == DLCI_CLOSED)
4396 return;
4397 /* Caution needed: If we implement reliable transport classes
4398 then the data being transmitted can't simply be junked once
4399 it has first hit the stack. Until then we can just blow it
4400 away */
4401 spin_lock_irqsave(&dlci->lock, flags);
4402 kfifo_reset(&dlci->fifo);
4403 spin_unlock_irqrestore(&dlci->lock, flags);
4404 /* Need to unhook this DLCI from the transmit queue logic */
4405}
4406
4407static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
4408{
4409 /* The FIFO handles the queue so the kernel will do the right
4410 thing waiting on chars_in_buffer before calling us. No work
4411 to do here */
4412}
4413
4414static int gsmtty_tiocmget(struct tty_struct *tty)
4415{
4416 struct gsm_dlci *dlci = tty->driver_data;
4417 if (dlci->state == DLCI_CLOSED)
4418 return -EINVAL;
4419 return dlci->modem_rx;
4420}
4421
4422static int gsmtty_tiocmset(struct tty_struct *tty,
4423 unsigned int set, unsigned int clear)
4424{
4425 struct gsm_dlci *dlci = tty->driver_data;
4426 unsigned int modem_tx = dlci->modem_tx;
4427
4428 if (dlci->state == DLCI_CLOSED)
4429 return -EINVAL;
4430 modem_tx &= ~clear;
4431 modem_tx |= set;
4432
4433 if (modem_tx != dlci->modem_tx) {
4434 dlci->modem_tx = modem_tx;
4435 return gsm_modem_update(dlci, 0);
4436 }
4437 return 0;
4438}
4439
4440
4441static int gsmtty_ioctl(struct tty_struct *tty,
4442 unsigned int cmd, unsigned long arg)
4443{
4444 struct gsm_dlci *dlci = tty->driver_data;
4445 struct gsm_netconfig nc;
4446 struct gsm_dlci_config dc;
4447 int index;
4448
4449 if (dlci->state == DLCI_CLOSED)
4450 return -EINVAL;
4451 switch (cmd) {
4452 case GSMIOC_ENABLE_NET:
4453 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
4454 return -EFAULT;
4455 nc.if_name[IFNAMSIZ-1] = '\0';
4456 /* return net interface index or error code */
4457 mutex_lock(&dlci->mutex);
4458 index = gsm_create_network(dlci, &nc);
4459 mutex_unlock(&dlci->mutex);
4460 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
4461 return -EFAULT;
4462 return index;
4463 case GSMIOC_DISABLE_NET:
4464 if (!capable(CAP_NET_ADMIN))
4465 return -EPERM;
4466 mutex_lock(&dlci->mutex);
4467 gsm_destroy_network(dlci);
4468 mutex_unlock(&dlci->mutex);
4469 return 0;
4470 case GSMIOC_GETCONF_DLCI:
4471 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc)))
4472 return -EFAULT;
4473 if (dc.channel != dlci->addr)
4474 return -EPERM;
4475 gsm_dlci_copy_config_values(dlci, &dc);
4476 if (copy_to_user((void __user *)arg, &dc, sizeof(dc)))
4477 return -EFAULT;
4478 return 0;
4479 case GSMIOC_SETCONF_DLCI:
4480 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc)))
4481 return -EFAULT;
4482 if (dc.channel >= NUM_DLCI)
4483 return -EINVAL;
4484 if (dc.channel != 0 && dc.channel != dlci->addr)
4485 return -EPERM;
4486 return gsm_dlci_config(dlci, &dc, 1);
4487 case TIOCMIWAIT:
4488 return gsm_wait_modem_change(dlci, (u32)arg);
4489 default:
4490 return -ENOIOCTLCMD;
4491 }
4492}
4493
4494static void gsmtty_set_termios(struct tty_struct *tty,
4495 const struct ktermios *old)
4496{
4497 struct gsm_dlci *dlci = tty->driver_data;
4498 if (dlci->state == DLCI_CLOSED)
4499 return;
4500 /* For the moment its fixed. In actual fact the speed information
4501 for the virtual channel can be propogated in both directions by
4502 the RPN control message. This however rapidly gets nasty as we
4503 then have to remap modem signals each way according to whether
4504 our virtual cable is null modem etc .. */
4505 tty_termios_copy_hw(&tty->termios, old);
4506}
4507
4508static void gsmtty_throttle(struct tty_struct *tty)
4509{
4510 struct gsm_dlci *dlci = tty->driver_data;
4511 if (dlci->state == DLCI_CLOSED)
4512 return;
4513 if (C_CRTSCTS(tty))
4514 dlci->modem_tx &= ~TIOCM_RTS;
4515 dlci->throttled = true;
4516 /* Send an MSC with RTS cleared */
4517 gsm_modem_update(dlci, 0);
4518}
4519
4520static void gsmtty_unthrottle(struct tty_struct *tty)
4521{
4522 struct gsm_dlci *dlci = tty->driver_data;
4523 if (dlci->state == DLCI_CLOSED)
4524 return;
4525 if (C_CRTSCTS(tty))
4526 dlci->modem_tx |= TIOCM_RTS;
4527 dlci->throttled = false;
4528 /* Send an MSC with RTS set */
4529 gsm_modem_update(dlci, 0);
4530}
4531
4532static int gsmtty_break_ctl(struct tty_struct *tty, int state)
4533{
4534 struct gsm_dlci *dlci = tty->driver_data;
4535 int encode = 0; /* Off */
4536 if (dlci->state == DLCI_CLOSED)
4537 return -EINVAL;
4538
4539 if (state == -1) /* "On indefinitely" - we can't encode this
4540 properly */
4541 encode = 0x0F;
4542 else if (state > 0) {
4543 encode = state / 200; /* mS to encoding */
4544 if (encode > 0x0F)
4545 encode = 0x0F; /* Best effort */
4546 }
4547 return gsm_modem_update(dlci, encode);
4548}
4549
4550static void gsmtty_cleanup(struct tty_struct *tty)
4551{
4552 struct gsm_dlci *dlci = tty->driver_data;
4553 struct gsm_mux *gsm = dlci->gsm;
4554
4555 dlci_put(dlci);
4556 dlci_put(gsm->dlci[0]);
4557 mux_put(gsm);
4558}
4559
4560/* Virtual ttys for the demux */
4561static const struct tty_operations gsmtty_ops = {
4562 .install = gsmtty_install,
4563 .open = gsmtty_open,
4564 .close = gsmtty_close,
4565 .write = gsmtty_write,
4566 .write_room = gsmtty_write_room,
4567 .chars_in_buffer = gsmtty_chars_in_buffer,
4568 .flush_buffer = gsmtty_flush_buffer,
4569 .ioctl = gsmtty_ioctl,
4570 .throttle = gsmtty_throttle,
4571 .unthrottle = gsmtty_unthrottle,
4572 .set_termios = gsmtty_set_termios,
4573 .hangup = gsmtty_hangup,
4574 .wait_until_sent = gsmtty_wait_until_sent,
4575 .tiocmget = gsmtty_tiocmget,
4576 .tiocmset = gsmtty_tiocmset,
4577 .break_ctl = gsmtty_break_ctl,
4578 .cleanup = gsmtty_cleanup,
4579};
4580
4581
4582
4583static int __init gsm_init(void)
4584{
4585 /* Fill in our line protocol discipline, and register it */
4586 int status = tty_register_ldisc(&tty_ldisc_packet);
4587 if (status != 0) {
4588 pr_err("n_gsm: can't register line discipline (err = %d)\n",
4589 status);
4590 return status;
4591 }
4592
4593 gsm_tty_driver = tty_alloc_driver(GSM_TTY_MINORS, TTY_DRIVER_REAL_RAW |
4594 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_HARDWARE_BREAK);
4595 if (IS_ERR(gsm_tty_driver)) {
4596 pr_err("gsm_init: tty allocation failed.\n");
4597 status = PTR_ERR(gsm_tty_driver);
4598 goto err_unreg_ldisc;
4599 }
4600 gsm_tty_driver->driver_name = "gsmtty";
4601 gsm_tty_driver->name = "gsmtty";
4602 gsm_tty_driver->major = 0; /* Dynamic */
4603 gsm_tty_driver->minor_start = 0;
4604 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
4605 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
4606 gsm_tty_driver->init_termios = tty_std_termios;
4607 /* Fixme */
4608 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
4609 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
4610
4611 if (tty_register_driver(gsm_tty_driver)) {
4612 pr_err("gsm_init: tty registration failed.\n");
4613 status = -EBUSY;
4614 goto err_put_driver;
4615 }
4616 pr_debug("gsm_init: loaded as %d,%d.\n",
4617 gsm_tty_driver->major, gsm_tty_driver->minor_start);
4618 return 0;
4619err_put_driver:
4620 tty_driver_kref_put(gsm_tty_driver);
4621err_unreg_ldisc:
4622 tty_unregister_ldisc(&tty_ldisc_packet);
4623 return status;
4624}
4625
4626static void __exit gsm_exit(void)
4627{
4628 tty_unregister_ldisc(&tty_ldisc_packet);
4629 tty_unregister_driver(gsm_tty_driver);
4630 tty_driver_kref_put(gsm_tty_driver);
4631}
4632
4633module_init(gsm_init);
4634module_exit(gsm_exit);
4635
4636
4637MODULE_LICENSE("GPL");
4638MODULE_ALIAS_LDISC(N_GSM0710);