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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[];
101};
102
103enum gsm_dlci_state {
104 DLCI_CLOSED,
105 DLCI_OPENING, /* Sending SABM not seen UA */
106 DLCI_OPEN, /* SABM/UA complete */
107 DLCI_CLOSING, /* Sending DISC not seen UA/DM */
108};
109
110enum gsm_dlci_mode {
111 DLCI_MODE_ABM, /* Normal Asynchronous Balanced Mode */
112 DLCI_MODE_ADM, /* Asynchronous Disconnected Mode */
113};
114
115/*
116 * Each active data link has a gsm_dlci structure associated which ties
117 * the link layer to an optional tty (if the tty side is open). To avoid
118 * complexity right now these are only ever freed up when the mux is
119 * shut down.
120 *
121 * At the moment we don't free DLCI objects until the mux is torn down
122 * this avoid object life time issues but might be worth review later.
123 */
124
125struct gsm_dlci {
126 struct gsm_mux *gsm;
127 int addr;
128 enum gsm_dlci_state state;
129 struct mutex mutex;
130
131 /* Link layer */
132 enum gsm_dlci_mode mode;
133 spinlock_t lock; /* Protects the internal state */
134 struct timer_list t1; /* Retransmit timer for SABM and UA */
135 int retries;
136 /* Uplink tty if active */
137 struct tty_port port; /* The tty bound to this DLCI if there is one */
138 struct kfifo fifo; /* Queue fifo for the DLCI */
139 int adaption; /* Adaption layer in use */
140 int prev_adaption;
141 u32 modem_rx; /* Our incoming virtual modem lines */
142 u32 modem_tx; /* Our outgoing modem lines */
143 bool dead; /* Refuse re-open */
144 /* Flow control */
145 bool throttled; /* Private copy of throttle state */
146 bool constipated; /* Throttle status for outgoing */
147 /* Packetised I/O */
148 struct sk_buff *skb; /* Frame being sent */
149 struct sk_buff_head skb_list; /* Queued frames */
150 /* Data handling callback */
151 void (*data)(struct gsm_dlci *dlci, const u8 *data, int len);
152 void (*prev_data)(struct gsm_dlci *dlci, const u8 *data, int len);
153 struct net_device *net; /* network interface, if created */
154};
155
156/* DLCI 0, 62/63 are special or reserved see gsmtty_open */
157
158#define NUM_DLCI 64
159
160/*
161 * DLCI 0 is used to pass control blocks out of band of the data
162 * flow (and with a higher link priority). One command can be outstanding
163 * at a time and we use this structure to manage them. They are created
164 * and destroyed by the user context, and updated by the receive paths
165 * and timers
166 */
167
168struct gsm_control {
169 u8 cmd; /* Command we are issuing */
170 u8 *data; /* Data for the command in case we retransmit */
171 int len; /* Length of block for retransmission */
172 int done; /* Done flag */
173 int error; /* Error if any */
174};
175
176enum gsm_mux_state {
177 GSM_SEARCH,
178 GSM_START,
179 GSM_ADDRESS,
180 GSM_CONTROL,
181 GSM_LEN,
182 GSM_DATA,
183 GSM_FCS,
184 GSM_OVERRUN,
185 GSM_LEN0,
186 GSM_LEN1,
187 GSM_SSOF,
188};
189
190/*
191 * Each GSM mux we have is represented by this structure. If we are
192 * operating as an ldisc then we use this structure as our ldisc
193 * state. We need to sort out lifetimes and locking with respect
194 * to the gsm mux array. For now we don't free DLCI objects that
195 * have been instantiated until the mux itself is terminated.
196 *
197 * To consider further: tty open versus mux shutdown.
198 */
199
200struct gsm_mux {
201 struct tty_struct *tty; /* The tty our ldisc is bound to */
202 spinlock_t lock;
203 struct mutex mutex;
204 unsigned int num;
205 struct kref ref;
206
207 /* Events on the GSM channel */
208 wait_queue_head_t event;
209
210 /* Bits for GSM mode decoding */
211
212 /* Framing Layer */
213 unsigned char *buf;
214 enum gsm_mux_state state;
215 unsigned int len;
216 unsigned int address;
217 unsigned int count;
218 bool escape;
219 int encoding;
220 u8 control;
221 u8 fcs;
222 u8 received_fcs;
223 u8 *txframe; /* TX framing buffer */
224
225 /* Methods for the receiver side */
226 void (*receive)(struct gsm_mux *gsm, u8 ch);
227 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
228 /* And transmit side */
229 int (*output)(struct gsm_mux *mux, u8 *data, int len);
230
231 /* Link Layer */
232 unsigned int mru;
233 unsigned int mtu;
234 int initiator; /* Did we initiate connection */
235 bool dead; /* Has the mux been shut down */
236 struct gsm_dlci *dlci[NUM_DLCI];
237 bool constipated; /* Asked by remote to shut up */
238
239 spinlock_t tx_lock;
240 unsigned int tx_bytes; /* TX data outstanding */
241#define TX_THRESH_HI 8192
242#define TX_THRESH_LO 2048
243 struct list_head tx_list; /* Pending data packets */
244
245 /* Control messages */
246 struct timer_list t2_timer; /* Retransmit timer for commands */
247 int cretries; /* Command retry counter */
248 struct gsm_control *pending_cmd;/* Our current pending command */
249 spinlock_t control_lock; /* Protects the pending command */
250
251 /* Configuration */
252 int adaption; /* 1 or 2 supported */
253 u8 ftype; /* UI or UIH */
254 int t1, t2; /* Timers in 1/100th of a sec */
255 int n2; /* Retry count */
256
257 /* Statistics (not currently exposed) */
258 unsigned long bad_fcs;
259 unsigned long malformed;
260 unsigned long io_error;
261 unsigned long bad_size;
262 unsigned long unsupported;
263};
264
265
266/*
267 * Mux objects - needed so that we can translate a tty index into the
268 * relevant mux and DLCI.
269 */
270
271#define MAX_MUX 4 /* 256 minors */
272static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
273static spinlock_t gsm_mux_lock;
274
275static struct tty_driver *gsm_tty_driver;
276
277/*
278 * This section of the driver logic implements the GSM encodings
279 * both the basic and the 'advanced'. Reliable transport is not
280 * supported.
281 */
282
283#define CR 0x02
284#define EA 0x01
285#define PF 0x10
286
287/* I is special: the rest are ..*/
288#define RR 0x01
289#define UI 0x03
290#define RNR 0x05
291#define REJ 0x09
292#define DM 0x0F
293#define SABM 0x2F
294#define DISC 0x43
295#define UA 0x63
296#define UIH 0xEF
297
298/* Channel commands */
299#define CMD_NSC 0x09
300#define CMD_TEST 0x11
301#define CMD_PSC 0x21
302#define CMD_RLS 0x29
303#define CMD_FCOFF 0x31
304#define CMD_PN 0x41
305#define CMD_RPN 0x49
306#define CMD_FCON 0x51
307#define CMD_CLD 0x61
308#define CMD_SNC 0x69
309#define CMD_MSC 0x71
310
311/* Virtual modem bits */
312#define MDM_FC 0x01
313#define MDM_RTC 0x02
314#define MDM_RTR 0x04
315#define MDM_IC 0x20
316#define MDM_DV 0x40
317
318#define GSM0_SOF 0xF9
319#define GSM1_SOF 0x7E
320#define GSM1_ESCAPE 0x7D
321#define GSM1_ESCAPE_BITS 0x20
322#define XON 0x11
323#define XOFF 0x13
324
325static const struct tty_port_operations gsm_port_ops;
326
327/*
328 * CRC table for GSM 0710
329 */
330
331static const u8 gsm_fcs8[256] = {
332 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
333 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
334 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
335 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
336 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
337 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
338 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
339 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
340 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
341 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
342 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
343 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
344 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
345 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
346 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
347 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
348 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
349 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
350 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
351 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
352 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
353 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
354 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
355 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
356 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
357 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
358 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
359 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
360 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
361 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
362 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
363 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
364};
365
366#define INIT_FCS 0xFF
367#define GOOD_FCS 0xCF
368
369/**
370 * gsm_fcs_add - update FCS
371 * @fcs: Current FCS
372 * @c: Next data
373 *
374 * Update the FCS to include c. Uses the algorithm in the specification
375 * notes.
376 */
377
378static inline u8 gsm_fcs_add(u8 fcs, u8 c)
379{
380 return gsm_fcs8[fcs ^ c];
381}
382
383/**
384 * gsm_fcs_add_block - update FCS for a block
385 * @fcs: Current FCS
386 * @c: buffer of data
387 * @len: length of buffer
388 *
389 * Update the FCS to include c. Uses the algorithm in the specification
390 * notes.
391 */
392
393static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
394{
395 while (len--)
396 fcs = gsm_fcs8[fcs ^ *c++];
397 return fcs;
398}
399
400/**
401 * gsm_read_ea - read a byte into an EA
402 * @val: variable holding value
403 * c: byte going into the EA
404 *
405 * Processes one byte of an EA. Updates the passed variable
406 * and returns 1 if the EA is now completely read
407 */
408
409static int gsm_read_ea(unsigned int *val, u8 c)
410{
411 /* Add the next 7 bits into the value */
412 *val <<= 7;
413 *val |= c >> 1;
414 /* Was this the last byte of the EA 1 = yes*/
415 return c & EA;
416}
417
418/**
419 * gsm_encode_modem - encode modem data bits
420 * @dlci: DLCI to encode from
421 *
422 * Returns the correct GSM encoded modem status bits (6 bit field) for
423 * the current status of the DLCI and attached tty object
424 */
425
426static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
427{
428 u8 modembits = 0;
429 /* FC is true flow control not modem bits */
430 if (dlci->throttled)
431 modembits |= MDM_FC;
432 if (dlci->modem_tx & TIOCM_DTR)
433 modembits |= MDM_RTC;
434 if (dlci->modem_tx & TIOCM_RTS)
435 modembits |= MDM_RTR;
436 if (dlci->modem_tx & TIOCM_RI)
437 modembits |= MDM_IC;
438 if (dlci->modem_tx & TIOCM_CD)
439 modembits |= MDM_DV;
440 return modembits;
441}
442
443/**
444 * gsm_print_packet - display a frame for debug
445 * @hdr: header to print before decode
446 * @addr: address EA from the frame
447 * @cr: C/R bit from the frame
448 * @control: control including PF bit
449 * @data: following data bytes
450 * @dlen: length of data
451 *
452 * Displays a packet in human readable format for debugging purposes. The
453 * style is based on amateur radio LAP-B dump display.
454 */
455
456static void gsm_print_packet(const char *hdr, int addr, int cr,
457 u8 control, const u8 *data, int dlen)
458{
459 if (!(debug & 1))
460 return;
461
462 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
463
464 switch (control & ~PF) {
465 case SABM:
466 pr_cont("SABM");
467 break;
468 case UA:
469 pr_cont("UA");
470 break;
471 case DISC:
472 pr_cont("DISC");
473 break;
474 case DM:
475 pr_cont("DM");
476 break;
477 case UI:
478 pr_cont("UI");
479 break;
480 case UIH:
481 pr_cont("UIH");
482 break;
483 default:
484 if (!(control & 0x01)) {
485 pr_cont("I N(S)%d N(R)%d",
486 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
487 } else switch (control & 0x0F) {
488 case RR:
489 pr_cont("RR(%d)", (control & 0xE0) >> 5);
490 break;
491 case RNR:
492 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
493 break;
494 case REJ:
495 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
496 break;
497 default:
498 pr_cont("[%02X]", control);
499 }
500 }
501
502 if (control & PF)
503 pr_cont("(P)");
504 else
505 pr_cont("(F)");
506
507 print_hex_dump_bytes("", DUMP_PREFIX_NONE, data, dlen);
508}
509
510
511/*
512 * Link level transmission side
513 */
514
515/**
516 * gsm_stuff_packet - bytestuff a packet
517 * @ibuf: input
518 * @obuf: output
519 * @len: length of input
520 *
521 * Expand a buffer by bytestuffing it. The worst case size change
522 * is doubling and the caller is responsible for handing out
523 * suitable sized buffers.
524 */
525
526static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
527{
528 int olen = 0;
529 while (len--) {
530 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
531 || *input == XON || *input == XOFF) {
532 *output++ = GSM1_ESCAPE;
533 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
534 olen++;
535 } else
536 *output++ = *input++;
537 olen++;
538 }
539 return olen;
540}
541
542/**
543 * gsm_send - send a control frame
544 * @gsm: our GSM mux
545 * @addr: address for control frame
546 * @cr: command/response bit
547 * @control: control byte including PF bit
548 *
549 * Format up and transmit a control frame. These do not go via the
550 * queueing logic as they should be transmitted ahead of data when
551 * they are needed.
552 *
553 * FIXME: Lock versus data TX path
554 */
555
556static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
557{
558 int len;
559 u8 cbuf[10];
560 u8 ibuf[3];
561
562 switch (gsm->encoding) {
563 case 0:
564 cbuf[0] = GSM0_SOF;
565 cbuf[1] = (addr << 2) | (cr << 1) | EA;
566 cbuf[2] = control;
567 cbuf[3] = EA; /* Length of data = 0 */
568 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
569 cbuf[5] = GSM0_SOF;
570 len = 6;
571 break;
572 case 1:
573 case 2:
574 /* Control frame + packing (but not frame stuffing) in mode 1 */
575 ibuf[0] = (addr << 2) | (cr << 1) | EA;
576 ibuf[1] = control;
577 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
578 /* Stuffing may double the size worst case */
579 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
580 /* Now add the SOF markers */
581 cbuf[0] = GSM1_SOF;
582 cbuf[len + 1] = GSM1_SOF;
583 /* FIXME: we can omit the lead one in many cases */
584 len += 2;
585 break;
586 default:
587 WARN_ON(1);
588 return;
589 }
590 gsm->output(gsm, cbuf, len);
591 gsm_print_packet("-->", addr, cr, control, NULL, 0);
592}
593
594/**
595 * gsm_response - send a control response
596 * @gsm: our GSM mux
597 * @addr: address for control frame
598 * @control: control byte including PF bit
599 *
600 * Format up and transmit a link level response frame.
601 */
602
603static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
604{
605 gsm_send(gsm, addr, 0, control);
606}
607
608/**
609 * gsm_command - send a control command
610 * @gsm: our GSM mux
611 * @addr: address for control frame
612 * @control: control byte including PF bit
613 *
614 * Format up and transmit a link level command frame.
615 */
616
617static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
618{
619 gsm_send(gsm, addr, 1, control);
620}
621
622/* Data transmission */
623
624#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
625
626/**
627 * gsm_data_alloc - allocate data frame
628 * @gsm: GSM mux
629 * @addr: DLCI address
630 * @len: length excluding header and FCS
631 * @ctrl: control byte
632 *
633 * Allocate a new data buffer for sending frames with data. Space is left
634 * at the front for header bytes but that is treated as an implementation
635 * detail and not for the high level code to use
636 */
637
638static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
639 u8 ctrl)
640{
641 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
642 GFP_ATOMIC);
643 if (m == NULL)
644 return NULL;
645 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
646 m->len = len;
647 m->addr = addr;
648 m->ctrl = ctrl;
649 INIT_LIST_HEAD(&m->list);
650 return m;
651}
652
653/**
654 * gsm_data_kick - poke the queue
655 * @gsm: GSM Mux
656 *
657 * The tty device has called us to indicate that room has appeared in
658 * the transmit queue. Ram more data into the pipe if we have any
659 * If we have been flow-stopped by a CMD_FCOFF, then we can only
660 * send messages on DLCI0 until CMD_FCON
661 *
662 * FIXME: lock against link layer control transmissions
663 */
664
665static void gsm_data_kick(struct gsm_mux *gsm, struct gsm_dlci *dlci)
666{
667 struct gsm_msg *msg, *nmsg;
668 int len;
669
670 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
671 if (gsm->constipated && msg->addr)
672 continue;
673 if (gsm->encoding != 0) {
674 gsm->txframe[0] = GSM1_SOF;
675 len = gsm_stuff_frame(msg->data,
676 gsm->txframe + 1, msg->len);
677 gsm->txframe[len + 1] = GSM1_SOF;
678 len += 2;
679 } else {
680 gsm->txframe[0] = GSM0_SOF;
681 memcpy(gsm->txframe + 1 , msg->data, msg->len);
682 gsm->txframe[msg->len + 1] = GSM0_SOF;
683 len = msg->len + 2;
684 }
685
686 if (debug & 4)
687 print_hex_dump_bytes("gsm_data_kick: ",
688 DUMP_PREFIX_OFFSET,
689 gsm->txframe, len);
690 if (gsm->output(gsm, gsm->txframe, len) < 0)
691 break;
692 /* FIXME: Can eliminate one SOF in many more cases */
693 gsm->tx_bytes -= msg->len;
694
695 list_del(&msg->list);
696 kfree(msg);
697
698 if (dlci) {
699 tty_port_tty_wakeup(&dlci->port);
700 } else {
701 int i = 0;
702
703 for (i = 0; i < NUM_DLCI; i++)
704 if (gsm->dlci[i])
705 tty_port_tty_wakeup(&gsm->dlci[i]->port);
706 }
707 }
708}
709
710/**
711 * __gsm_data_queue - queue a UI or UIH frame
712 * @dlci: DLCI sending the data
713 * @msg: message queued
714 *
715 * Add data to the transmit queue and try and get stuff moving
716 * out of the mux tty if not already doing so. The Caller must hold
717 * the gsm tx lock.
718 */
719
720static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
721{
722 struct gsm_mux *gsm = dlci->gsm;
723 u8 *dp = msg->data;
724 u8 *fcs = dp + msg->len;
725
726 /* Fill in the header */
727 if (gsm->encoding == 0) {
728 if (msg->len < 128)
729 *--dp = (msg->len << 1) | EA;
730 else {
731 *--dp = (msg->len >> 7); /* bits 7 - 15 */
732 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
733 }
734 }
735
736 *--dp = msg->ctrl;
737 if (gsm->initiator)
738 *--dp = (msg->addr << 2) | 2 | EA;
739 else
740 *--dp = (msg->addr << 2) | EA;
741 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
742 /* Ugly protocol layering violation */
743 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
744 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
745 *fcs = 0xFF - *fcs;
746
747 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
748 msg->data, msg->len);
749
750 /* Move the header back and adjust the length, also allow for the FCS
751 now tacked on the end */
752 msg->len += (msg->data - dp) + 1;
753 msg->data = dp;
754
755 /* Add to the actual output queue */
756 list_add_tail(&msg->list, &gsm->tx_list);
757 gsm->tx_bytes += msg->len;
758 gsm_data_kick(gsm, dlci);
759}
760
761/**
762 * gsm_data_queue - queue a UI or UIH frame
763 * @dlci: DLCI sending the data
764 * @msg: message queued
765 *
766 * Add data to the transmit queue and try and get stuff moving
767 * out of the mux tty if not already doing so. Take the
768 * the gsm tx lock and dlci lock.
769 */
770
771static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
772{
773 unsigned long flags;
774 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
775 __gsm_data_queue(dlci, msg);
776 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
777}
778
779/**
780 * gsm_dlci_data_output - try and push data out of a DLCI
781 * @gsm: mux
782 * @dlci: the DLCI to pull data from
783 *
784 * Pull data from a DLCI and send it into the transmit queue if there
785 * is data. Keep to the MRU of the mux. This path handles the usual tty
786 * interface which is a byte stream with optional modem data.
787 *
788 * Caller must hold the tx_lock of the mux.
789 */
790
791static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
792{
793 struct gsm_msg *msg;
794 u8 *dp;
795 int len, total_size, size;
796 int h = dlci->adaption - 1;
797
798 total_size = 0;
799 while (1) {
800 len = kfifo_len(&dlci->fifo);
801 if (len == 0)
802 return total_size;
803
804 /* MTU/MRU count only the data bits */
805 if (len > gsm->mtu)
806 len = gsm->mtu;
807
808 size = len + h;
809
810 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
811 /* FIXME: need a timer or something to kick this so it can't
812 get stuck with no work outstanding and no buffer free */
813 if (msg == NULL)
814 return -ENOMEM;
815 dp = msg->data;
816 switch (dlci->adaption) {
817 case 1: /* Unstructured */
818 break;
819 case 2: /* Unstructed with modem bits.
820 Always one byte as we never send inline break data */
821 *dp++ = gsm_encode_modem(dlci);
822 break;
823 }
824 WARN_ON(kfifo_out_locked(&dlci->fifo, dp , len, &dlci->lock) != len);
825 __gsm_data_queue(dlci, msg);
826 total_size += size;
827 }
828 /* Bytes of data we used up */
829 return total_size;
830}
831
832/**
833 * gsm_dlci_data_output_framed - try and push data out of a DLCI
834 * @gsm: mux
835 * @dlci: the DLCI to pull data from
836 *
837 * Pull data from a DLCI and send it into the transmit queue if there
838 * is data. Keep to the MRU of the mux. This path handles framed data
839 * queued as skbuffs to the DLCI.
840 *
841 * Caller must hold the tx_lock of the mux.
842 */
843
844static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
845 struct gsm_dlci *dlci)
846{
847 struct gsm_msg *msg;
848 u8 *dp;
849 int len, size;
850 int last = 0, first = 0;
851 int overhead = 0;
852
853 /* One byte per frame is used for B/F flags */
854 if (dlci->adaption == 4)
855 overhead = 1;
856
857 /* dlci->skb is locked by tx_lock */
858 if (dlci->skb == NULL) {
859 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
860 if (dlci->skb == NULL)
861 return 0;
862 first = 1;
863 }
864 len = dlci->skb->len + overhead;
865
866 /* MTU/MRU count only the data bits */
867 if (len > gsm->mtu) {
868 if (dlci->adaption == 3) {
869 /* Over long frame, bin it */
870 dev_kfree_skb_any(dlci->skb);
871 dlci->skb = NULL;
872 return 0;
873 }
874 len = gsm->mtu;
875 } else
876 last = 1;
877
878 size = len + overhead;
879 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
880
881 /* FIXME: need a timer or something to kick this so it can't
882 get stuck with no work outstanding and no buffer free */
883 if (msg == NULL) {
884 skb_queue_tail(&dlci->skb_list, dlci->skb);
885 dlci->skb = NULL;
886 return -ENOMEM;
887 }
888 dp = msg->data;
889
890 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
891 /* Flag byte to carry the start/end info */
892 *dp++ = last << 7 | first << 6 | 1; /* EA */
893 len--;
894 }
895 memcpy(dp, dlci->skb->data, len);
896 skb_pull(dlci->skb, len);
897 __gsm_data_queue(dlci, msg);
898 if (last) {
899 dev_kfree_skb_any(dlci->skb);
900 dlci->skb = NULL;
901 }
902 return size;
903}
904
905/**
906 * gsm_dlci_data_sweep - look for data to send
907 * @gsm: the GSM mux
908 *
909 * Sweep the GSM mux channels in priority order looking for ones with
910 * data to send. We could do with optimising this scan a bit. We aim
911 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
912 * TX_THRESH_LO we get called again
913 *
914 * FIXME: We should round robin between groups and in theory you can
915 * renegotiate DLCI priorities with optional stuff. Needs optimising.
916 */
917
918static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
919{
920 int len;
921 /* Priority ordering: We should do priority with RR of the groups */
922 int i = 1;
923
924 while (i < NUM_DLCI) {
925 struct gsm_dlci *dlci;
926
927 if (gsm->tx_bytes > TX_THRESH_HI)
928 break;
929 dlci = gsm->dlci[i];
930 if (dlci == NULL || dlci->constipated) {
931 i++;
932 continue;
933 }
934 if (dlci->adaption < 3 && !dlci->net)
935 len = gsm_dlci_data_output(gsm, dlci);
936 else
937 len = gsm_dlci_data_output_framed(gsm, dlci);
938 if (len < 0)
939 break;
940 /* DLCI empty - try the next */
941 if (len == 0)
942 i++;
943 }
944}
945
946/**
947 * gsm_dlci_data_kick - transmit if possible
948 * @dlci: DLCI to kick
949 *
950 * Transmit data from this DLCI if the queue is empty. We can't rely on
951 * a tty wakeup except when we filled the pipe so we need to fire off
952 * new data ourselves in other cases.
953 */
954
955static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
956{
957 unsigned long flags;
958 int sweep;
959
960 if (dlci->constipated)
961 return;
962
963 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
964 /* If we have nothing running then we need to fire up */
965 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
966 if (dlci->gsm->tx_bytes == 0) {
967 if (dlci->net)
968 gsm_dlci_data_output_framed(dlci->gsm, dlci);
969 else
970 gsm_dlci_data_output(dlci->gsm, dlci);
971 }
972 if (sweep)
973 gsm_dlci_data_sweep(dlci->gsm);
974 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
975}
976
977/*
978 * Control message processing
979 */
980
981
982/**
983 * gsm_control_reply - send a response frame to a control
984 * @gsm: gsm channel
985 * @cmd: the command to use
986 * @data: data to follow encoded info
987 * @dlen: length of data
988 *
989 * Encode up and queue a UI/UIH frame containing our response.
990 */
991
992static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data,
993 int dlen)
994{
995 struct gsm_msg *msg;
996 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
997 if (msg == NULL)
998 return;
999 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1000 msg->data[1] = (dlen << 1) | EA;
1001 memcpy(msg->data + 2, data, dlen);
1002 gsm_data_queue(gsm->dlci[0], msg);
1003}
1004
1005/**
1006 * gsm_process_modem - process received modem status
1007 * @tty: virtual tty bound to the DLCI
1008 * @dlci: DLCI to affect
1009 * @modem: modem bits (full EA)
1010 *
1011 * Used when a modem control message or line state inline in adaption
1012 * layer 2 is processed. Sort out the local modem state and throttles
1013 */
1014
1015static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1016 u32 modem, int clen)
1017{
1018 int mlines = 0;
1019 u8 brk = 0;
1020 int fc;
1021
1022 /* The modem status command can either contain one octet (v.24 signals)
1023 or two octets (v.24 signals + break signals). The length field will
1024 either be 2 or 3 respectively. This is specified in section
1025 5.4.6.3.7 of the 27.010 mux spec. */
1026
1027 if (clen == 2)
1028 modem = modem & 0x7f;
1029 else {
1030 brk = modem & 0x7f;
1031 modem = (modem >> 7) & 0x7f;
1032 }
1033
1034 /* Flow control/ready to communicate */
1035 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1036 if (fc && !dlci->constipated) {
1037 /* Need to throttle our output on this device */
1038 dlci->constipated = true;
1039 } else if (!fc && dlci->constipated) {
1040 dlci->constipated = false;
1041 gsm_dlci_data_kick(dlci);
1042 }
1043
1044 /* Map modem bits */
1045 if (modem & MDM_RTC)
1046 mlines |= TIOCM_DSR | TIOCM_DTR;
1047 if (modem & MDM_RTR)
1048 mlines |= TIOCM_RTS | TIOCM_CTS;
1049 if (modem & MDM_IC)
1050 mlines |= TIOCM_RI;
1051 if (modem & MDM_DV)
1052 mlines |= TIOCM_CD;
1053
1054 /* Carrier drop -> hangup */
1055 if (tty) {
1056 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1057 if (!C_CLOCAL(tty))
1058 tty_hangup(tty);
1059 }
1060 if (brk & 0x01)
1061 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1062 dlci->modem_rx = mlines;
1063}
1064
1065/**
1066 * gsm_control_modem - modem status received
1067 * @gsm: GSM channel
1068 * @data: data following command
1069 * @clen: command length
1070 *
1071 * We have received a modem status control message. This is used by
1072 * the GSM mux protocol to pass virtual modem line status and optionally
1073 * to indicate break signals. Unpack it, convert to Linux representation
1074 * and if need be stuff a break message down the tty.
1075 */
1076
1077static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
1078{
1079 unsigned int addr = 0;
1080 unsigned int modem = 0;
1081 unsigned int brk = 0;
1082 struct gsm_dlci *dlci;
1083 int len = clen;
1084 const u8 *dp = data;
1085 struct tty_struct *tty;
1086
1087 while (gsm_read_ea(&addr, *dp++) == 0) {
1088 len--;
1089 if (len == 0)
1090 return;
1091 }
1092 /* Must be at least one byte following the EA */
1093 len--;
1094 if (len <= 0)
1095 return;
1096
1097 addr >>= 1;
1098 /* Closed port, or invalid ? */
1099 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1100 return;
1101 dlci = gsm->dlci[addr];
1102
1103 while (gsm_read_ea(&modem, *dp++) == 0) {
1104 len--;
1105 if (len == 0)
1106 return;
1107 }
1108 len--;
1109 if (len > 0) {
1110 while (gsm_read_ea(&brk, *dp++) == 0) {
1111 len--;
1112 if (len == 0)
1113 return;
1114 }
1115 modem <<= 7;
1116 modem |= (brk & 0x7f);
1117 }
1118 tty = tty_port_tty_get(&dlci->port);
1119 gsm_process_modem(tty, dlci, modem, clen);
1120 if (tty) {
1121 tty_wakeup(tty);
1122 tty_kref_put(tty);
1123 }
1124 gsm_control_reply(gsm, CMD_MSC, data, clen);
1125}
1126
1127/**
1128 * gsm_control_rls - remote line status
1129 * @gsm: GSM channel
1130 * @data: data bytes
1131 * @clen: data length
1132 *
1133 * The modem sends us a two byte message on the control channel whenever
1134 * it wishes to send us an error state from the virtual link. Stuff
1135 * this into the uplink tty if present
1136 */
1137
1138static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen)
1139{
1140 struct tty_port *port;
1141 unsigned int addr = 0;
1142 u8 bits;
1143 int len = clen;
1144 const u8 *dp = data;
1145
1146 while (gsm_read_ea(&addr, *dp++) == 0) {
1147 len--;
1148 if (len == 0)
1149 return;
1150 }
1151 /* Must be at least one byte following ea */
1152 len--;
1153 if (len <= 0)
1154 return;
1155 addr >>= 1;
1156 /* Closed port, or invalid ? */
1157 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1158 return;
1159 /* No error ? */
1160 bits = *dp;
1161 if ((bits & 1) == 0)
1162 return;
1163
1164 port = &gsm->dlci[addr]->port;
1165
1166 if (bits & 2)
1167 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1168 if (bits & 4)
1169 tty_insert_flip_char(port, 0, TTY_PARITY);
1170 if (bits & 8)
1171 tty_insert_flip_char(port, 0, TTY_FRAME);
1172
1173 tty_flip_buffer_push(port);
1174
1175 gsm_control_reply(gsm, CMD_RLS, data, clen);
1176}
1177
1178static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1179
1180/**
1181 * gsm_control_message - DLCI 0 control processing
1182 * @gsm: our GSM mux
1183 * @command: the command EA
1184 * @data: data beyond the command/length EAs
1185 * @clen: length
1186 *
1187 * Input processor for control messages from the other end of the link.
1188 * Processes the incoming request and queues a response frame or an
1189 * NSC response if not supported
1190 */
1191
1192static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1193 const u8 *data, int clen)
1194{
1195 u8 buf[1];
1196 unsigned long flags;
1197
1198 switch (command) {
1199 case CMD_CLD: {
1200 struct gsm_dlci *dlci = gsm->dlci[0];
1201 /* Modem wishes to close down */
1202 if (dlci) {
1203 dlci->dead = true;
1204 gsm->dead = true;
1205 gsm_dlci_begin_close(dlci);
1206 }
1207 }
1208 break;
1209 case CMD_TEST:
1210 /* Modem wishes to test, reply with the data */
1211 gsm_control_reply(gsm, CMD_TEST, data, clen);
1212 break;
1213 case CMD_FCON:
1214 /* Modem can accept data again */
1215 gsm->constipated = false;
1216 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1217 /* Kick the link in case it is idling */
1218 spin_lock_irqsave(&gsm->tx_lock, flags);
1219 gsm_data_kick(gsm, NULL);
1220 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1221 break;
1222 case CMD_FCOFF:
1223 /* Modem wants us to STFU */
1224 gsm->constipated = true;
1225 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1226 break;
1227 case CMD_MSC:
1228 /* Out of band modem line change indicator for a DLCI */
1229 gsm_control_modem(gsm, data, clen);
1230 break;
1231 case CMD_RLS:
1232 /* Out of band error reception for a DLCI */
1233 gsm_control_rls(gsm, data, clen);
1234 break;
1235 case CMD_PSC:
1236 /* Modem wishes to enter power saving state */
1237 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1238 break;
1239 /* Optional unsupported commands */
1240 case CMD_PN: /* Parameter negotiation */
1241 case CMD_RPN: /* Remote port negotiation */
1242 case CMD_SNC: /* Service negotiation command */
1243 default:
1244 /* Reply to bad commands with an NSC */
1245 buf[0] = command;
1246 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1247 break;
1248 }
1249}
1250
1251/**
1252 * gsm_control_response - process a response to our control
1253 * @gsm: our GSM mux
1254 * @command: the command (response) EA
1255 * @data: data beyond the command/length EA
1256 * @clen: length
1257 *
1258 * Process a response to an outstanding command. We only allow a single
1259 * control message in flight so this is fairly easy. All the clean up
1260 * is done by the caller, we just update the fields, flag it as done
1261 * and return
1262 */
1263
1264static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1265 const u8 *data, int clen)
1266{
1267 struct gsm_control *ctrl;
1268 unsigned long flags;
1269
1270 spin_lock_irqsave(&gsm->control_lock, flags);
1271
1272 ctrl = gsm->pending_cmd;
1273 /* Does the reply match our command */
1274 command |= 1;
1275 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1276 /* Our command was replied to, kill the retry timer */
1277 del_timer(&gsm->t2_timer);
1278 gsm->pending_cmd = NULL;
1279 /* Rejected by the other end */
1280 if (command == CMD_NSC)
1281 ctrl->error = -EOPNOTSUPP;
1282 ctrl->done = 1;
1283 wake_up(&gsm->event);
1284 }
1285 spin_unlock_irqrestore(&gsm->control_lock, flags);
1286}
1287
1288/**
1289 * gsm_control_transmit - send control packet
1290 * @gsm: gsm mux
1291 * @ctrl: frame to send
1292 *
1293 * Send out a pending control command (called under control lock)
1294 */
1295
1296static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1297{
1298 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1299 if (msg == NULL)
1300 return;
1301 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1302 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1303 gsm_data_queue(gsm->dlci[0], msg);
1304}
1305
1306/**
1307 * gsm_control_retransmit - retransmit a control frame
1308 * @data: pointer to our gsm object
1309 *
1310 * Called off the T2 timer expiry in order to retransmit control frames
1311 * that have been lost in the system somewhere. The control_lock protects
1312 * us from colliding with another sender or a receive completion event.
1313 * In that situation the timer may still occur in a small window but
1314 * gsm->pending_cmd will be NULL and we just let the timer expire.
1315 */
1316
1317static void gsm_control_retransmit(struct timer_list *t)
1318{
1319 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer);
1320 struct gsm_control *ctrl;
1321 unsigned long flags;
1322 spin_lock_irqsave(&gsm->control_lock, flags);
1323 ctrl = gsm->pending_cmd;
1324 if (ctrl) {
1325 gsm->cretries--;
1326 if (gsm->cretries == 0) {
1327 gsm->pending_cmd = NULL;
1328 ctrl->error = -ETIMEDOUT;
1329 ctrl->done = 1;
1330 spin_unlock_irqrestore(&gsm->control_lock, flags);
1331 wake_up(&gsm->event);
1332 return;
1333 }
1334 gsm_control_transmit(gsm, ctrl);
1335 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1336 }
1337 spin_unlock_irqrestore(&gsm->control_lock, flags);
1338}
1339
1340/**
1341 * gsm_control_send - send a control frame on DLCI 0
1342 * @gsm: the GSM channel
1343 * @command: command to send including CR bit
1344 * @data: bytes of data (must be kmalloced)
1345 * @len: length of the block to send
1346 *
1347 * Queue and dispatch a control command. Only one command can be
1348 * active at a time. In theory more can be outstanding but the matching
1349 * gets really complicated so for now stick to one outstanding.
1350 */
1351
1352static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1353 unsigned int command, u8 *data, int clen)
1354{
1355 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1356 GFP_KERNEL);
1357 unsigned long flags;
1358 if (ctrl == NULL)
1359 return NULL;
1360retry:
1361 wait_event(gsm->event, gsm->pending_cmd == NULL);
1362 spin_lock_irqsave(&gsm->control_lock, flags);
1363 if (gsm->pending_cmd != NULL) {
1364 spin_unlock_irqrestore(&gsm->control_lock, flags);
1365 goto retry;
1366 }
1367 ctrl->cmd = command;
1368 ctrl->data = data;
1369 ctrl->len = clen;
1370 gsm->pending_cmd = ctrl;
1371
1372 /* If DLCI0 is in ADM mode skip retries, it won't respond */
1373 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
1374 gsm->cretries = 1;
1375 else
1376 gsm->cretries = gsm->n2;
1377
1378 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1379 gsm_control_transmit(gsm, ctrl);
1380 spin_unlock_irqrestore(&gsm->control_lock, flags);
1381 return ctrl;
1382}
1383
1384/**
1385 * gsm_control_wait - wait for a control to finish
1386 * @gsm: GSM mux
1387 * @control: control we are waiting on
1388 *
1389 * Waits for the control to complete or time out. Frees any used
1390 * resources and returns 0 for success, or an error if the remote
1391 * rejected or ignored the request.
1392 */
1393
1394static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1395{
1396 int err;
1397 wait_event(gsm->event, control->done == 1);
1398 err = control->error;
1399 kfree(control);
1400 return err;
1401}
1402
1403
1404/*
1405 * DLCI level handling: Needs krefs
1406 */
1407
1408/*
1409 * State transitions and timers
1410 */
1411
1412/**
1413 * gsm_dlci_close - a DLCI has closed
1414 * @dlci: DLCI that closed
1415 *
1416 * Perform processing when moving a DLCI into closed state. If there
1417 * is an attached tty this is hung up
1418 */
1419
1420static void gsm_dlci_close(struct gsm_dlci *dlci)
1421{
1422 del_timer(&dlci->t1);
1423 if (debug & 8)
1424 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1425 dlci->state = DLCI_CLOSED;
1426 if (dlci->addr != 0) {
1427 tty_port_tty_hangup(&dlci->port, false);
1428 kfifo_reset(&dlci->fifo);
1429 } else
1430 dlci->gsm->dead = true;
1431 wake_up(&dlci->gsm->event);
1432 /* A DLCI 0 close is a MUX termination so we need to kick that
1433 back to userspace somehow */
1434}
1435
1436/**
1437 * gsm_dlci_open - a DLCI has opened
1438 * @dlci: DLCI that opened
1439 *
1440 * Perform processing when moving a DLCI into open state.
1441 */
1442
1443static void gsm_dlci_open(struct gsm_dlci *dlci)
1444{
1445 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1446 open -> open */
1447 del_timer(&dlci->t1);
1448 /* This will let a tty open continue */
1449 dlci->state = DLCI_OPEN;
1450 if (debug & 8)
1451 pr_debug("DLCI %d goes open.\n", dlci->addr);
1452 wake_up(&dlci->gsm->event);
1453}
1454
1455/**
1456 * gsm_dlci_t1 - T1 timer expiry
1457 * @dlci: DLCI that opened
1458 *
1459 * The T1 timer handles retransmits of control frames (essentially of
1460 * SABM and DISC). We resend the command until the retry count runs out
1461 * in which case an opening port goes back to closed and a closing port
1462 * is simply put into closed state (any further frames from the other
1463 * end will get a DM response)
1464 *
1465 * Some control dlci can stay in ADM mode with other dlci working just
1466 * fine. In that case we can just keep the control dlci open after the
1467 * DLCI_OPENING retries time out.
1468 */
1469
1470static void gsm_dlci_t1(struct timer_list *t)
1471{
1472 struct gsm_dlci *dlci = from_timer(dlci, t, t1);
1473 struct gsm_mux *gsm = dlci->gsm;
1474
1475 switch (dlci->state) {
1476 case DLCI_OPENING:
1477 dlci->retries--;
1478 if (dlci->retries) {
1479 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1480 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1481 } else if (!dlci->addr && gsm->control == (DM | PF)) {
1482 if (debug & 8)
1483 pr_info("DLCI %d opening in ADM mode.\n",
1484 dlci->addr);
1485 dlci->mode = DLCI_MODE_ADM;
1486 gsm_dlci_open(dlci);
1487 } else {
1488 gsm_dlci_close(dlci);
1489 }
1490
1491 break;
1492 case DLCI_CLOSING:
1493 dlci->retries--;
1494 if (dlci->retries) {
1495 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1496 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1497 } else
1498 gsm_dlci_close(dlci);
1499 break;
1500 default:
1501 pr_debug("%s: unhandled state: %d\n", __func__, dlci->state);
1502 break;
1503 }
1504}
1505
1506/**
1507 * gsm_dlci_begin_open - start channel open procedure
1508 * @dlci: DLCI to open
1509 *
1510 * Commence opening a DLCI from the Linux side. We issue SABM messages
1511 * to the modem which should then reply with a UA or ADM, at which point
1512 * we will move into open state. Opening is done asynchronously with retry
1513 * running off timers and the responses.
1514 */
1515
1516static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1517{
1518 struct gsm_mux *gsm = dlci->gsm;
1519 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1520 return;
1521 dlci->retries = gsm->n2;
1522 dlci->state = DLCI_OPENING;
1523 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1524 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1525}
1526
1527/**
1528 * gsm_dlci_begin_close - start channel open procedure
1529 * @dlci: DLCI to open
1530 *
1531 * Commence closing a DLCI from the Linux side. We issue DISC messages
1532 * to the modem which should then reply with a UA, at which point we
1533 * will move into closed state. Closing is done asynchronously with retry
1534 * off timers. We may also receive a DM reply from the other end which
1535 * indicates the channel was already closed.
1536 */
1537
1538static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1539{
1540 struct gsm_mux *gsm = dlci->gsm;
1541 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1542 return;
1543 dlci->retries = gsm->n2;
1544 dlci->state = DLCI_CLOSING;
1545 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1546 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1547}
1548
1549/**
1550 * gsm_dlci_data - data arrived
1551 * @dlci: channel
1552 * @data: block of bytes received
1553 * @len: length of received block
1554 *
1555 * A UI or UIH frame has arrived which contains data for a channel
1556 * other than the control channel. If the relevant virtual tty is
1557 * open we shovel the bits down it, if not we drop them.
1558 */
1559
1560static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
1561{
1562 /* krefs .. */
1563 struct tty_port *port = &dlci->port;
1564 struct tty_struct *tty;
1565 unsigned int modem = 0;
1566 int len = clen;
1567
1568 if (debug & 16)
1569 pr_debug("%d bytes for tty\n", len);
1570 switch (dlci->adaption) {
1571 /* Unsupported types */
1572 case 4: /* Packetised interruptible data */
1573 break;
1574 case 3: /* Packetised uininterruptible voice/data */
1575 break;
1576 case 2: /* Asynchronous serial with line state in each frame */
1577 while (gsm_read_ea(&modem, *data++) == 0) {
1578 len--;
1579 if (len == 0)
1580 return;
1581 }
1582 tty = tty_port_tty_get(port);
1583 if (tty) {
1584 gsm_process_modem(tty, dlci, modem, clen);
1585 tty_kref_put(tty);
1586 }
1587 fallthrough;
1588 case 1: /* Line state will go via DLCI 0 controls only */
1589 default:
1590 tty_insert_flip_string(port, data, len);
1591 tty_flip_buffer_push(port);
1592 }
1593}
1594
1595/**
1596 * gsm_dlci_control - data arrived on control channel
1597 * @dlci: channel
1598 * @data: block of bytes received
1599 * @len: length of received block
1600 *
1601 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1602 * control channel. This should contain a command EA followed by
1603 * control data bytes. The command EA contains a command/response bit
1604 * and we divide up the work accordingly.
1605 */
1606
1607static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
1608{
1609 /* See what command is involved */
1610 unsigned int command = 0;
1611 while (len-- > 0) {
1612 if (gsm_read_ea(&command, *data++) == 1) {
1613 int clen = *data++;
1614 len--;
1615 /* FIXME: this is properly an EA */
1616 clen >>= 1;
1617 /* Malformed command ? */
1618 if (clen > len)
1619 return;
1620 if (command & 1)
1621 gsm_control_message(dlci->gsm, command,
1622 data, clen);
1623 else
1624 gsm_control_response(dlci->gsm, command,
1625 data, clen);
1626 return;
1627 }
1628 }
1629}
1630
1631/*
1632 * Allocate/Free DLCI channels
1633 */
1634
1635/**
1636 * gsm_dlci_alloc - allocate a DLCI
1637 * @gsm: GSM mux
1638 * @addr: address of the DLCI
1639 *
1640 * Allocate and install a new DLCI object into the GSM mux.
1641 *
1642 * FIXME: review locking races
1643 */
1644
1645static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1646{
1647 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1648 if (dlci == NULL)
1649 return NULL;
1650 spin_lock_init(&dlci->lock);
1651 mutex_init(&dlci->mutex);
1652 if (kfifo_alloc(&dlci->fifo, 4096, GFP_KERNEL) < 0) {
1653 kfree(dlci);
1654 return NULL;
1655 }
1656
1657 skb_queue_head_init(&dlci->skb_list);
1658 timer_setup(&dlci->t1, gsm_dlci_t1, 0);
1659 tty_port_init(&dlci->port);
1660 dlci->port.ops = &gsm_port_ops;
1661 dlci->gsm = gsm;
1662 dlci->addr = addr;
1663 dlci->adaption = gsm->adaption;
1664 dlci->state = DLCI_CLOSED;
1665 if (addr)
1666 dlci->data = gsm_dlci_data;
1667 else
1668 dlci->data = gsm_dlci_command;
1669 gsm->dlci[addr] = dlci;
1670 return dlci;
1671}
1672
1673/**
1674 * gsm_dlci_free - free DLCI
1675 * @dlci: DLCI to free
1676 *
1677 * Free up a DLCI.
1678 *
1679 * Can sleep.
1680 */
1681static void gsm_dlci_free(struct tty_port *port)
1682{
1683 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
1684
1685 del_timer_sync(&dlci->t1);
1686 dlci->gsm->dlci[dlci->addr] = NULL;
1687 kfifo_free(&dlci->fifo);
1688 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1689 dev_kfree_skb(dlci->skb);
1690 kfree(dlci);
1691}
1692
1693static inline void dlci_get(struct gsm_dlci *dlci)
1694{
1695 tty_port_get(&dlci->port);
1696}
1697
1698static inline void dlci_put(struct gsm_dlci *dlci)
1699{
1700 tty_port_put(&dlci->port);
1701}
1702
1703static void gsm_destroy_network(struct gsm_dlci *dlci);
1704
1705/**
1706 * gsm_dlci_release - release DLCI
1707 * @dlci: DLCI to destroy
1708 *
1709 * Release a DLCI. Actual free is deferred until either
1710 * mux is closed or tty is closed - whichever is last.
1711 *
1712 * Can sleep.
1713 */
1714static void gsm_dlci_release(struct gsm_dlci *dlci)
1715{
1716 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1717 if (tty) {
1718 mutex_lock(&dlci->mutex);
1719 gsm_destroy_network(dlci);
1720 mutex_unlock(&dlci->mutex);
1721
1722 tty_hangup(tty);
1723
1724 tty_port_tty_set(&dlci->port, NULL);
1725 tty_kref_put(tty);
1726 }
1727 dlci->state = DLCI_CLOSED;
1728 dlci_put(dlci);
1729}
1730
1731/*
1732 * LAPBish link layer logic
1733 */
1734
1735/**
1736 * gsm_queue - a GSM frame is ready to process
1737 * @gsm: pointer to our gsm mux
1738 *
1739 * At this point in time a frame has arrived and been demangled from
1740 * the line encoding. All the differences between the encodings have
1741 * been handled below us and the frame is unpacked into the structures.
1742 * The fcs holds the header FCS but any data FCS must be added here.
1743 */
1744
1745static void gsm_queue(struct gsm_mux *gsm)
1746{
1747 struct gsm_dlci *dlci;
1748 u8 cr;
1749 int address;
1750 /* We have to sneak a look at the packet body to do the FCS.
1751 A somewhat layering violation in the spec */
1752
1753 if ((gsm->control & ~PF) == UI)
1754 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1755 if (gsm->encoding == 0) {
1756 /* WARNING: gsm->received_fcs is used for
1757 gsm->encoding = 0 only.
1758 In this case it contain the last piece of data
1759 required to generate final CRC */
1760 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1761 }
1762 if (gsm->fcs != GOOD_FCS) {
1763 gsm->bad_fcs++;
1764 if (debug & 4)
1765 pr_debug("BAD FCS %02x\n", gsm->fcs);
1766 return;
1767 }
1768 address = gsm->address >> 1;
1769 if (address >= NUM_DLCI)
1770 goto invalid;
1771
1772 cr = gsm->address & 1; /* C/R bit */
1773
1774 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1775
1776 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1777 dlci = gsm->dlci[address];
1778
1779 switch (gsm->control) {
1780 case SABM|PF:
1781 if (cr == 0)
1782 goto invalid;
1783 if (dlci == NULL)
1784 dlci = gsm_dlci_alloc(gsm, address);
1785 if (dlci == NULL)
1786 return;
1787 if (dlci->dead)
1788 gsm_response(gsm, address, DM);
1789 else {
1790 gsm_response(gsm, address, UA);
1791 gsm_dlci_open(dlci);
1792 }
1793 break;
1794 case DISC|PF:
1795 if (cr == 0)
1796 goto invalid;
1797 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1798 gsm_response(gsm, address, DM);
1799 return;
1800 }
1801 /* Real close complete */
1802 gsm_response(gsm, address, UA);
1803 gsm_dlci_close(dlci);
1804 break;
1805 case UA:
1806 case UA|PF:
1807 if (cr == 0 || dlci == NULL)
1808 break;
1809 switch (dlci->state) {
1810 case DLCI_CLOSING:
1811 gsm_dlci_close(dlci);
1812 break;
1813 case DLCI_OPENING:
1814 gsm_dlci_open(dlci);
1815 break;
1816 default:
1817 pr_debug("%s: unhandled state: %d\n", __func__,
1818 dlci->state);
1819 break;
1820 }
1821 break;
1822 case DM: /* DM can be valid unsolicited */
1823 case DM|PF:
1824 if (cr)
1825 goto invalid;
1826 if (dlci == NULL)
1827 return;
1828 gsm_dlci_close(dlci);
1829 break;
1830 case UI:
1831 case UI|PF:
1832 case UIH:
1833 case UIH|PF:
1834#if 0
1835 if (cr)
1836 goto invalid;
1837#endif
1838 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1839 gsm_command(gsm, address, DM|PF);
1840 return;
1841 }
1842 dlci->data(dlci, gsm->buf, gsm->len);
1843 break;
1844 default:
1845 goto invalid;
1846 }
1847 return;
1848invalid:
1849 gsm->malformed++;
1850 return;
1851}
1852
1853
1854/**
1855 * gsm0_receive - perform processing for non-transparency
1856 * @gsm: gsm data for this ldisc instance
1857 * @c: character
1858 *
1859 * Receive bytes in gsm mode 0
1860 */
1861
1862static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1863{
1864 unsigned int len;
1865
1866 switch (gsm->state) {
1867 case GSM_SEARCH: /* SOF marker */
1868 if (c == GSM0_SOF) {
1869 gsm->state = GSM_ADDRESS;
1870 gsm->address = 0;
1871 gsm->len = 0;
1872 gsm->fcs = INIT_FCS;
1873 }
1874 break;
1875 case GSM_ADDRESS: /* Address EA */
1876 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1877 if (gsm_read_ea(&gsm->address, c))
1878 gsm->state = GSM_CONTROL;
1879 break;
1880 case GSM_CONTROL: /* Control Byte */
1881 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1882 gsm->control = c;
1883 gsm->state = GSM_LEN0;
1884 break;
1885 case GSM_LEN0: /* Length EA */
1886 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1887 if (gsm_read_ea(&gsm->len, c)) {
1888 if (gsm->len > gsm->mru) {
1889 gsm->bad_size++;
1890 gsm->state = GSM_SEARCH;
1891 break;
1892 }
1893 gsm->count = 0;
1894 if (!gsm->len)
1895 gsm->state = GSM_FCS;
1896 else
1897 gsm->state = GSM_DATA;
1898 break;
1899 }
1900 gsm->state = GSM_LEN1;
1901 break;
1902 case GSM_LEN1:
1903 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1904 len = c;
1905 gsm->len |= len << 7;
1906 if (gsm->len > gsm->mru) {
1907 gsm->bad_size++;
1908 gsm->state = GSM_SEARCH;
1909 break;
1910 }
1911 gsm->count = 0;
1912 if (!gsm->len)
1913 gsm->state = GSM_FCS;
1914 else
1915 gsm->state = GSM_DATA;
1916 break;
1917 case GSM_DATA: /* Data */
1918 gsm->buf[gsm->count++] = c;
1919 if (gsm->count == gsm->len)
1920 gsm->state = GSM_FCS;
1921 break;
1922 case GSM_FCS: /* FCS follows the packet */
1923 gsm->received_fcs = c;
1924 gsm_queue(gsm);
1925 gsm->state = GSM_SSOF;
1926 break;
1927 case GSM_SSOF:
1928 if (c == GSM0_SOF) {
1929 gsm->state = GSM_SEARCH;
1930 break;
1931 }
1932 break;
1933 default:
1934 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
1935 break;
1936 }
1937}
1938
1939/**
1940 * gsm1_receive - perform processing for non-transparency
1941 * @gsm: gsm data for this ldisc instance
1942 * @c: character
1943 *
1944 * Receive bytes in mode 1 (Advanced option)
1945 */
1946
1947static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1948{
1949 if (c == GSM1_SOF) {
1950 /* EOF is only valid in frame if we have got to the data state
1951 and received at least one byte (the FCS) */
1952 if (gsm->state == GSM_DATA && gsm->count) {
1953 /* Extract the FCS */
1954 gsm->count--;
1955 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1956 gsm->len = gsm->count;
1957 gsm_queue(gsm);
1958 gsm->state = GSM_START;
1959 return;
1960 }
1961 /* Any partial frame was a runt so go back to start */
1962 if (gsm->state != GSM_START) {
1963 gsm->malformed++;
1964 gsm->state = GSM_START;
1965 }
1966 /* A SOF in GSM_START means we are still reading idling or
1967 framing bytes */
1968 return;
1969 }
1970
1971 if (c == GSM1_ESCAPE) {
1972 gsm->escape = true;
1973 return;
1974 }
1975
1976 /* Only an unescaped SOF gets us out of GSM search */
1977 if (gsm->state == GSM_SEARCH)
1978 return;
1979
1980 if (gsm->escape) {
1981 c ^= GSM1_ESCAPE_BITS;
1982 gsm->escape = false;
1983 }
1984 switch (gsm->state) {
1985 case GSM_START: /* First byte after SOF */
1986 gsm->address = 0;
1987 gsm->state = GSM_ADDRESS;
1988 gsm->fcs = INIT_FCS;
1989 fallthrough;
1990 case GSM_ADDRESS: /* Address continuation */
1991 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1992 if (gsm_read_ea(&gsm->address, c))
1993 gsm->state = GSM_CONTROL;
1994 break;
1995 case GSM_CONTROL: /* Control Byte */
1996 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1997 gsm->control = c;
1998 gsm->count = 0;
1999 gsm->state = GSM_DATA;
2000 break;
2001 case GSM_DATA: /* Data */
2002 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
2003 gsm->state = GSM_OVERRUN;
2004 gsm->bad_size++;
2005 } else
2006 gsm->buf[gsm->count++] = c;
2007 break;
2008 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
2009 break;
2010 default:
2011 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
2012 break;
2013 }
2014}
2015
2016/**
2017 * gsm_error - handle tty error
2018 * @gsm: ldisc data
2019 * @data: byte received (may be invalid)
2020 * @flag: error received
2021 *
2022 * Handle an error in the receipt of data for a frame. Currently we just
2023 * go back to hunting for a SOF.
2024 *
2025 * FIXME: better diagnostics ?
2026 */
2027
2028static void gsm_error(struct gsm_mux *gsm,
2029 unsigned char data, unsigned char flag)
2030{
2031 gsm->state = GSM_SEARCH;
2032 gsm->io_error++;
2033}
2034
2035static int gsm_disconnect(struct gsm_mux *gsm)
2036{
2037 struct gsm_dlci *dlci = gsm->dlci[0];
2038 struct gsm_control *gc;
2039
2040 if (!dlci)
2041 return 0;
2042
2043 /* In theory disconnecting DLCI 0 is sufficient but for some
2044 modems this is apparently not the case. */
2045 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2046 if (gc)
2047 gsm_control_wait(gsm, gc);
2048
2049 del_timer_sync(&gsm->t2_timer);
2050 /* Now we are sure T2 has stopped */
2051
2052 gsm_dlci_begin_close(dlci);
2053 wait_event_interruptible(gsm->event,
2054 dlci->state == DLCI_CLOSED);
2055
2056 if (signal_pending(current))
2057 return -EINTR;
2058
2059 return 0;
2060}
2061
2062/**
2063 * gsm_cleanup_mux - generic GSM protocol cleanup
2064 * @gsm: our mux
2065 *
2066 * Clean up the bits of the mux which are the same for all framing
2067 * protocols. Remove the mux from the mux table, stop all the timers
2068 * and then shut down each device hanging up the channels as we go.
2069 */
2070
2071static void gsm_cleanup_mux(struct gsm_mux *gsm)
2072{
2073 int i;
2074 struct gsm_dlci *dlci = gsm->dlci[0];
2075 struct gsm_msg *txq, *ntxq;
2076
2077 gsm->dead = true;
2078
2079 spin_lock(&gsm_mux_lock);
2080 for (i = 0; i < MAX_MUX; i++) {
2081 if (gsm_mux[i] == gsm) {
2082 gsm_mux[i] = NULL;
2083 break;
2084 }
2085 }
2086 spin_unlock(&gsm_mux_lock);
2087 /* open failed before registering => nothing to do */
2088 if (i == MAX_MUX)
2089 return;
2090
2091 del_timer_sync(&gsm->t2_timer);
2092 /* Now we are sure T2 has stopped */
2093 if (dlci)
2094 dlci->dead = true;
2095
2096 /* Free up any link layer users */
2097 mutex_lock(&gsm->mutex);
2098 for (i = 0; i < NUM_DLCI; i++)
2099 if (gsm->dlci[i])
2100 gsm_dlci_release(gsm->dlci[i]);
2101 mutex_unlock(&gsm->mutex);
2102 /* Now wipe the queues */
2103 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2104 kfree(txq);
2105 INIT_LIST_HEAD(&gsm->tx_list);
2106}
2107
2108/**
2109 * gsm_activate_mux - generic GSM setup
2110 * @gsm: our mux
2111 *
2112 * Set up the bits of the mux which are the same for all framing
2113 * protocols. Add the mux to the mux table so it can be opened and
2114 * finally kick off connecting to DLCI 0 on the modem.
2115 */
2116
2117static int gsm_activate_mux(struct gsm_mux *gsm)
2118{
2119 struct gsm_dlci *dlci;
2120 int i = 0;
2121
2122 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
2123 init_waitqueue_head(&gsm->event);
2124 spin_lock_init(&gsm->control_lock);
2125 spin_lock_init(&gsm->tx_lock);
2126
2127 if (gsm->encoding == 0)
2128 gsm->receive = gsm0_receive;
2129 else
2130 gsm->receive = gsm1_receive;
2131 gsm->error = gsm_error;
2132
2133 spin_lock(&gsm_mux_lock);
2134 for (i = 0; i < MAX_MUX; i++) {
2135 if (gsm_mux[i] == NULL) {
2136 gsm->num = i;
2137 gsm_mux[i] = gsm;
2138 break;
2139 }
2140 }
2141 spin_unlock(&gsm_mux_lock);
2142 if (i == MAX_MUX)
2143 return -EBUSY;
2144
2145 dlci = gsm_dlci_alloc(gsm, 0);
2146 if (dlci == NULL)
2147 return -ENOMEM;
2148 gsm->dead = false; /* Tty opens are now permissible */
2149 return 0;
2150}
2151
2152/**
2153 * gsm_free_mux - free up a mux
2154 * @mux: mux to free
2155 *
2156 * Dispose of allocated resources for a dead mux
2157 */
2158static void gsm_free_mux(struct gsm_mux *gsm)
2159{
2160 kfree(gsm->txframe);
2161 kfree(gsm->buf);
2162 kfree(gsm);
2163}
2164
2165/**
2166 * gsm_free_muxr - free up a mux
2167 * @mux: mux to free
2168 *
2169 * Dispose of allocated resources for a dead mux
2170 */
2171static void gsm_free_muxr(struct kref *ref)
2172{
2173 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2174 gsm_free_mux(gsm);
2175}
2176
2177static inline void mux_get(struct gsm_mux *gsm)
2178{
2179 kref_get(&gsm->ref);
2180}
2181
2182static inline void mux_put(struct gsm_mux *gsm)
2183{
2184 kref_put(&gsm->ref, gsm_free_muxr);
2185}
2186
2187static inline unsigned int mux_num_to_base(struct gsm_mux *gsm)
2188{
2189 return gsm->num * NUM_DLCI;
2190}
2191
2192static inline unsigned int mux_line_to_num(unsigned int line)
2193{
2194 return line / NUM_DLCI;
2195}
2196
2197/**
2198 * gsm_alloc_mux - allocate a mux
2199 *
2200 * Creates a new mux ready for activation.
2201 */
2202
2203static struct gsm_mux *gsm_alloc_mux(void)
2204{
2205 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2206 if (gsm == NULL)
2207 return NULL;
2208 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2209 if (gsm->buf == NULL) {
2210 kfree(gsm);
2211 return NULL;
2212 }
2213 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2214 if (gsm->txframe == NULL) {
2215 kfree(gsm->buf);
2216 kfree(gsm);
2217 return NULL;
2218 }
2219 spin_lock_init(&gsm->lock);
2220 mutex_init(&gsm->mutex);
2221 kref_init(&gsm->ref);
2222 INIT_LIST_HEAD(&gsm->tx_list);
2223
2224 gsm->t1 = T1;
2225 gsm->t2 = T2;
2226 gsm->n2 = N2;
2227 gsm->ftype = UIH;
2228 gsm->adaption = 1;
2229 gsm->encoding = 1;
2230 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2231 gsm->mtu = 64;
2232 gsm->dead = true; /* Avoid early tty opens */
2233
2234 return gsm;
2235}
2236
2237static void gsm_copy_config_values(struct gsm_mux *gsm,
2238 struct gsm_config *c)
2239{
2240 memset(c, 0, sizeof(*c));
2241 c->adaption = gsm->adaption;
2242 c->encapsulation = gsm->encoding;
2243 c->initiator = gsm->initiator;
2244 c->t1 = gsm->t1;
2245 c->t2 = gsm->t2;
2246 c->t3 = 0; /* Not supported */
2247 c->n2 = gsm->n2;
2248 if (gsm->ftype == UIH)
2249 c->i = 1;
2250 else
2251 c->i = 2;
2252 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i);
2253 c->mru = gsm->mru;
2254 c->mtu = gsm->mtu;
2255 c->k = 0;
2256}
2257
2258static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
2259{
2260 int need_close = 0;
2261 int need_restart = 0;
2262
2263 /* Stuff we don't support yet - UI or I frame transport, windowing */
2264 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2265 return -EOPNOTSUPP;
2266 /* Check the MRU/MTU range looks sane */
2267 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2268 return -EINVAL;
2269 if (c->n2 < 3)
2270 return -EINVAL;
2271 if (c->encapsulation > 1) /* Basic, advanced, no I */
2272 return -EINVAL;
2273 if (c->initiator > 1)
2274 return -EINVAL;
2275 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2276 return -EINVAL;
2277 /*
2278 * See what is needed for reconfiguration
2279 */
2280
2281 /* Timing fields */
2282 if (c->t1 != 0 && c->t1 != gsm->t1)
2283 need_restart = 1;
2284 if (c->t2 != 0 && c->t2 != gsm->t2)
2285 need_restart = 1;
2286 if (c->encapsulation != gsm->encoding)
2287 need_restart = 1;
2288 if (c->adaption != gsm->adaption)
2289 need_restart = 1;
2290 /* Requires care */
2291 if (c->initiator != gsm->initiator)
2292 need_close = 1;
2293 if (c->mru != gsm->mru)
2294 need_restart = 1;
2295 if (c->mtu != gsm->mtu)
2296 need_restart = 1;
2297
2298 /*
2299 * Close down what is needed, restart and initiate the new
2300 * configuration
2301 */
2302
2303 if (need_close || need_restart) {
2304 int ret;
2305
2306 ret = gsm_disconnect(gsm);
2307
2308 if (ret)
2309 return ret;
2310 }
2311 if (need_restart)
2312 gsm_cleanup_mux(gsm);
2313
2314 gsm->initiator = c->initiator;
2315 gsm->mru = c->mru;
2316 gsm->mtu = c->mtu;
2317 gsm->encoding = c->encapsulation;
2318 gsm->adaption = c->adaption;
2319 gsm->n2 = c->n2;
2320
2321 if (c->i == 1)
2322 gsm->ftype = UIH;
2323 else if (c->i == 2)
2324 gsm->ftype = UI;
2325
2326 if (c->t1)
2327 gsm->t1 = c->t1;
2328 if (c->t2)
2329 gsm->t2 = c->t2;
2330
2331 /*
2332 * FIXME: We need to separate activation/deactivation from adding
2333 * and removing from the mux array
2334 */
2335 if (need_restart)
2336 gsm_activate_mux(gsm);
2337 if (gsm->initiator && need_close)
2338 gsm_dlci_begin_open(gsm->dlci[0]);
2339 return 0;
2340}
2341
2342/**
2343 * gsmld_output - write to link
2344 * @gsm: our mux
2345 * @data: bytes to output
2346 * @len: size
2347 *
2348 * Write a block of data from the GSM mux to the data channel. This
2349 * will eventually be serialized from above but at the moment isn't.
2350 */
2351
2352static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2353{
2354 if (tty_write_room(gsm->tty) < len) {
2355 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2356 return -ENOSPC;
2357 }
2358 if (debug & 4)
2359 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2360 data, len);
2361 gsm->tty->ops->write(gsm->tty, data, len);
2362 return len;
2363}
2364
2365/**
2366 * gsmld_attach_gsm - mode set up
2367 * @tty: our tty structure
2368 * @gsm: our mux
2369 *
2370 * Set up the MUX for basic mode and commence connecting to the
2371 * modem. Currently called from the line discipline set up but
2372 * will need moving to an ioctl path.
2373 */
2374
2375static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2376{
2377 unsigned int base;
2378 int ret, i;
2379
2380 gsm->tty = tty_kref_get(tty);
2381 gsm->output = gsmld_output;
2382 ret = gsm_activate_mux(gsm);
2383 if (ret != 0)
2384 tty_kref_put(gsm->tty);
2385 else {
2386 /* Don't register device 0 - this is the control channel and not
2387 a usable tty interface */
2388 base = mux_num_to_base(gsm); /* Base for this MUX */
2389 for (i = 1; i < NUM_DLCI; i++)
2390 tty_register_device(gsm_tty_driver, base + i, NULL);
2391 }
2392 return ret;
2393}
2394
2395
2396/**
2397 * gsmld_detach_gsm - stop doing 0710 mux
2398 * @tty: tty attached to the mux
2399 * @gsm: mux
2400 *
2401 * Shutdown and then clean up the resources used by the line discipline
2402 */
2403
2404static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2405{
2406 unsigned int base = mux_num_to_base(gsm); /* Base for this MUX */
2407 int i;
2408
2409 WARN_ON(tty != gsm->tty);
2410 for (i = 1; i < NUM_DLCI; i++)
2411 tty_unregister_device(gsm_tty_driver, base + i);
2412 gsm_cleanup_mux(gsm);
2413 tty_kref_put(gsm->tty);
2414 gsm->tty = NULL;
2415}
2416
2417static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2418 char *fp, int count)
2419{
2420 struct gsm_mux *gsm = tty->disc_data;
2421 const unsigned char *dp;
2422 char *f;
2423 int i;
2424 char flags = TTY_NORMAL;
2425
2426 if (debug & 4)
2427 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2428 cp, count);
2429
2430 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2431 if (f)
2432 flags = *f++;
2433 switch (flags) {
2434 case TTY_NORMAL:
2435 gsm->receive(gsm, *dp);
2436 break;
2437 case TTY_OVERRUN:
2438 case TTY_BREAK:
2439 case TTY_PARITY:
2440 case TTY_FRAME:
2441 gsm->error(gsm, *dp, flags);
2442 break;
2443 default:
2444 WARN_ONCE(1, "%s: unknown flag %d\n",
2445 tty_name(tty), flags);
2446 break;
2447 }
2448 }
2449 /* FASYNC if needed ? */
2450 /* If clogged call tty_throttle(tty); */
2451}
2452
2453/**
2454 * gsmld_flush_buffer - clean input queue
2455 * @tty: terminal device
2456 *
2457 * Flush the input buffer. Called when the line discipline is
2458 * being closed, when the tty layer wants the buffer flushed (eg
2459 * at hangup).
2460 */
2461
2462static void gsmld_flush_buffer(struct tty_struct *tty)
2463{
2464}
2465
2466/**
2467 * gsmld_close - close the ldisc for this tty
2468 * @tty: device
2469 *
2470 * Called from the terminal layer when this line discipline is
2471 * being shut down, either because of a close or becsuse of a
2472 * discipline change. The function will not be called while other
2473 * ldisc methods are in progress.
2474 */
2475
2476static void gsmld_close(struct tty_struct *tty)
2477{
2478 struct gsm_mux *gsm = tty->disc_data;
2479
2480 gsmld_detach_gsm(tty, gsm);
2481
2482 gsmld_flush_buffer(tty);
2483 /* Do other clean up here */
2484 mux_put(gsm);
2485}
2486
2487/**
2488 * gsmld_open - open an ldisc
2489 * @tty: terminal to open
2490 *
2491 * Called when this line discipline is being attached to the
2492 * terminal device. Can sleep. Called serialized so that no
2493 * other events will occur in parallel. No further open will occur
2494 * until a close.
2495 */
2496
2497static int gsmld_open(struct tty_struct *tty)
2498{
2499 struct gsm_mux *gsm;
2500 int ret;
2501
2502 if (tty->ops->write == NULL)
2503 return -EINVAL;
2504
2505 /* Attach our ldisc data */
2506 gsm = gsm_alloc_mux();
2507 if (gsm == NULL)
2508 return -ENOMEM;
2509
2510 tty->disc_data = gsm;
2511 tty->receive_room = 65536;
2512
2513 /* Attach the initial passive connection */
2514 gsm->encoding = 1;
2515
2516 ret = gsmld_attach_gsm(tty, gsm);
2517 if (ret != 0) {
2518 gsm_cleanup_mux(gsm);
2519 mux_put(gsm);
2520 }
2521 return ret;
2522}
2523
2524/**
2525 * gsmld_write_wakeup - asynchronous I/O notifier
2526 * @tty: tty device
2527 *
2528 * Required for the ptys, serial driver etc. since processes
2529 * that attach themselves to the master and rely on ASYNC
2530 * IO must be woken up
2531 */
2532
2533static void gsmld_write_wakeup(struct tty_struct *tty)
2534{
2535 struct gsm_mux *gsm = tty->disc_data;
2536 unsigned long flags;
2537
2538 /* Queue poll */
2539 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2540 spin_lock_irqsave(&gsm->tx_lock, flags);
2541 gsm_data_kick(gsm, NULL);
2542 if (gsm->tx_bytes < TX_THRESH_LO) {
2543 gsm_dlci_data_sweep(gsm);
2544 }
2545 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2546}
2547
2548/**
2549 * gsmld_read - read function for tty
2550 * @tty: tty device
2551 * @file: file object
2552 * @buf: userspace buffer pointer
2553 * @nr: size of I/O
2554 *
2555 * Perform reads for the line discipline. We are guaranteed that the
2556 * line discipline will not be closed under us but we may get multiple
2557 * parallel readers and must handle this ourselves. We may also get
2558 * a hangup. Always called in user context, may sleep.
2559 *
2560 * This code must be sure never to sleep through a hangup.
2561 */
2562
2563static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2564 unsigned char __user *buf, size_t nr)
2565{
2566 return -EOPNOTSUPP;
2567}
2568
2569/**
2570 * gsmld_write - write function for tty
2571 * @tty: tty device
2572 * @file: file object
2573 * @buf: userspace buffer pointer
2574 * @nr: size of I/O
2575 *
2576 * Called when the owner of the device wants to send a frame
2577 * itself (or some other control data). The data is transferred
2578 * as-is and must be properly framed and checksummed as appropriate
2579 * by userspace. Frames are either sent whole or not at all as this
2580 * avoids pain user side.
2581 */
2582
2583static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2584 const unsigned char *buf, size_t nr)
2585{
2586 int space = tty_write_room(tty);
2587 if (space >= nr)
2588 return tty->ops->write(tty, buf, nr);
2589 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2590 return -ENOBUFS;
2591}
2592
2593/**
2594 * gsmld_poll - poll method for N_GSM0710
2595 * @tty: terminal device
2596 * @file: file accessing it
2597 * @wait: poll table
2598 *
2599 * Called when the line discipline is asked to poll() for data or
2600 * for special events. This code is not serialized with respect to
2601 * other events save open/close.
2602 *
2603 * This code must be sure never to sleep through a hangup.
2604 * Called without the kernel lock held - fine
2605 */
2606
2607static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
2608 poll_table *wait)
2609{
2610 __poll_t mask = 0;
2611 struct gsm_mux *gsm = tty->disc_data;
2612
2613 poll_wait(file, &tty->read_wait, wait);
2614 poll_wait(file, &tty->write_wait, wait);
2615 if (tty_hung_up_p(file))
2616 mask |= EPOLLHUP;
2617 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2618 mask |= EPOLLOUT | EPOLLWRNORM;
2619 if (gsm->dead)
2620 mask |= EPOLLHUP;
2621 return mask;
2622}
2623
2624static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2625 unsigned int cmd, unsigned long arg)
2626{
2627 struct gsm_config c;
2628 struct gsm_mux *gsm = tty->disc_data;
2629 unsigned int base;
2630
2631 switch (cmd) {
2632 case GSMIOC_GETCONF:
2633 gsm_copy_config_values(gsm, &c);
2634 if (copy_to_user((void __user *)arg, &c, sizeof(c)))
2635 return -EFAULT;
2636 return 0;
2637 case GSMIOC_SETCONF:
2638 if (copy_from_user(&c, (void __user *)arg, sizeof(c)))
2639 return -EFAULT;
2640 return gsm_config(gsm, &c);
2641 case GSMIOC_GETFIRST:
2642 base = mux_num_to_base(gsm);
2643 return put_user(base + 1, (__u32 __user *)arg);
2644 default:
2645 return n_tty_ioctl_helper(tty, file, cmd, arg);
2646 }
2647}
2648
2649/*
2650 * Network interface
2651 *
2652 */
2653
2654static int gsm_mux_net_open(struct net_device *net)
2655{
2656 pr_debug("%s called\n", __func__);
2657 netif_start_queue(net);
2658 return 0;
2659}
2660
2661static int gsm_mux_net_close(struct net_device *net)
2662{
2663 netif_stop_queue(net);
2664 return 0;
2665}
2666
2667static void dlci_net_free(struct gsm_dlci *dlci)
2668{
2669 if (!dlci->net) {
2670 WARN_ON(1);
2671 return;
2672 }
2673 dlci->adaption = dlci->prev_adaption;
2674 dlci->data = dlci->prev_data;
2675 free_netdev(dlci->net);
2676 dlci->net = NULL;
2677}
2678static void net_free(struct kref *ref)
2679{
2680 struct gsm_mux_net *mux_net;
2681 struct gsm_dlci *dlci;
2682
2683 mux_net = container_of(ref, struct gsm_mux_net, ref);
2684 dlci = mux_net->dlci;
2685
2686 if (dlci->net) {
2687 unregister_netdev(dlci->net);
2688 dlci_net_free(dlci);
2689 }
2690}
2691
2692static inline void muxnet_get(struct gsm_mux_net *mux_net)
2693{
2694 kref_get(&mux_net->ref);
2695}
2696
2697static inline void muxnet_put(struct gsm_mux_net *mux_net)
2698{
2699 kref_put(&mux_net->ref, net_free);
2700}
2701
2702static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
2703 struct net_device *net)
2704{
2705 struct gsm_mux_net *mux_net = netdev_priv(net);
2706 struct gsm_dlci *dlci = mux_net->dlci;
2707 muxnet_get(mux_net);
2708
2709 skb_queue_head(&dlci->skb_list, skb);
2710 net->stats.tx_packets++;
2711 net->stats.tx_bytes += skb->len;
2712 gsm_dlci_data_kick(dlci);
2713 /* And tell the kernel when the last transmit started. */
2714 netif_trans_update(net);
2715 muxnet_put(mux_net);
2716 return NETDEV_TX_OK;
2717}
2718
2719/* called when a packet did not ack after watchdogtimeout */
2720static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue)
2721{
2722 /* Tell syslog we are hosed. */
2723 dev_dbg(&net->dev, "Tx timed out.\n");
2724
2725 /* Update statistics */
2726 net->stats.tx_errors++;
2727}
2728
2729static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2730 const unsigned char *in_buf, int size)
2731{
2732 struct net_device *net = dlci->net;
2733 struct sk_buff *skb;
2734 struct gsm_mux_net *mux_net = netdev_priv(net);
2735 muxnet_get(mux_net);
2736
2737 /* Allocate an sk_buff */
2738 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2739 if (!skb) {
2740 /* We got no receive buffer. */
2741 net->stats.rx_dropped++;
2742 muxnet_put(mux_net);
2743 return;
2744 }
2745 skb_reserve(skb, NET_IP_ALIGN);
2746 skb_put_data(skb, in_buf, size);
2747
2748 skb->dev = net;
2749 skb->protocol = htons(ETH_P_IP);
2750
2751 /* Ship it off to the kernel */
2752 netif_rx(skb);
2753
2754 /* update out statistics */
2755 net->stats.rx_packets++;
2756 net->stats.rx_bytes += size;
2757 muxnet_put(mux_net);
2758 return;
2759}
2760
2761static void gsm_mux_net_init(struct net_device *net)
2762{
2763 static const struct net_device_ops gsm_netdev_ops = {
2764 .ndo_open = gsm_mux_net_open,
2765 .ndo_stop = gsm_mux_net_close,
2766 .ndo_start_xmit = gsm_mux_net_start_xmit,
2767 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2768 };
2769
2770 net->netdev_ops = &gsm_netdev_ops;
2771
2772 /* fill in the other fields */
2773 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2774 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2775 net->type = ARPHRD_NONE;
2776 net->tx_queue_len = 10;
2777}
2778
2779
2780/* caller holds the dlci mutex */
2781static void gsm_destroy_network(struct gsm_dlci *dlci)
2782{
2783 struct gsm_mux_net *mux_net;
2784
2785 pr_debug("destroy network interface\n");
2786 if (!dlci->net)
2787 return;
2788 mux_net = netdev_priv(dlci->net);
2789 muxnet_put(mux_net);
2790}
2791
2792
2793/* caller holds the dlci mutex */
2794static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2795{
2796 char *netname;
2797 int retval = 0;
2798 struct net_device *net;
2799 struct gsm_mux_net *mux_net;
2800
2801 if (!capable(CAP_NET_ADMIN))
2802 return -EPERM;
2803
2804 /* Already in a non tty mode */
2805 if (dlci->adaption > 2)
2806 return -EBUSY;
2807
2808 if (nc->protocol != htons(ETH_P_IP))
2809 return -EPROTONOSUPPORT;
2810
2811 if (nc->adaption != 3 && nc->adaption != 4)
2812 return -EPROTONOSUPPORT;
2813
2814 pr_debug("create network interface\n");
2815
2816 netname = "gsm%d";
2817 if (nc->if_name[0] != '\0')
2818 netname = nc->if_name;
2819 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
2820 NET_NAME_UNKNOWN, gsm_mux_net_init);
2821 if (!net) {
2822 pr_err("alloc_netdev failed\n");
2823 return -ENOMEM;
2824 }
2825 net->mtu = dlci->gsm->mtu;
2826 net->min_mtu = 8;
2827 net->max_mtu = dlci->gsm->mtu;
2828 mux_net = netdev_priv(net);
2829 mux_net->dlci = dlci;
2830 kref_init(&mux_net->ref);
2831 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2832
2833 /* reconfigure dlci for network */
2834 dlci->prev_adaption = dlci->adaption;
2835 dlci->prev_data = dlci->data;
2836 dlci->adaption = nc->adaption;
2837 dlci->data = gsm_mux_rx_netchar;
2838 dlci->net = net;
2839
2840 pr_debug("register netdev\n");
2841 retval = register_netdev(net);
2842 if (retval) {
2843 pr_err("network register fail %d\n", retval);
2844 dlci_net_free(dlci);
2845 return retval;
2846 }
2847 return net->ifindex; /* return network index */
2848}
2849
2850/* Line discipline for real tty */
2851static struct tty_ldisc_ops tty_ldisc_packet = {
2852 .owner = THIS_MODULE,
2853 .magic = TTY_LDISC_MAGIC,
2854 .name = "n_gsm",
2855 .open = gsmld_open,
2856 .close = gsmld_close,
2857 .flush_buffer = gsmld_flush_buffer,
2858 .read = gsmld_read,
2859 .write = gsmld_write,
2860 .ioctl = gsmld_ioctl,
2861 .poll = gsmld_poll,
2862 .receive_buf = gsmld_receive_buf,
2863 .write_wakeup = gsmld_write_wakeup
2864};
2865
2866/*
2867 * Virtual tty side
2868 */
2869
2870#define TX_SIZE 512
2871
2872static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2873{
2874 u8 modembits[5];
2875 struct gsm_control *ctrl;
2876 int len = 2;
2877
2878 if (brk)
2879 len++;
2880
2881 modembits[0] = len << 1 | EA; /* Data bytes */
2882 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2883 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2884 if (brk)
2885 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2886 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2887 if (ctrl == NULL)
2888 return -ENOMEM;
2889 return gsm_control_wait(dlci->gsm, ctrl);
2890}
2891
2892static int gsm_carrier_raised(struct tty_port *port)
2893{
2894 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2895 struct gsm_mux *gsm = dlci->gsm;
2896
2897 /* Not yet open so no carrier info */
2898 if (dlci->state != DLCI_OPEN)
2899 return 0;
2900 if (debug & 2)
2901 return 1;
2902
2903 /*
2904 * Basic mode with control channel in ADM mode may not respond
2905 * to CMD_MSC at all and modem_rx is empty.
2906 */
2907 if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM &&
2908 !dlci->modem_rx)
2909 return 1;
2910
2911 return dlci->modem_rx & TIOCM_CD;
2912}
2913
2914static void gsm_dtr_rts(struct tty_port *port, int onoff)
2915{
2916 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2917 unsigned int modem_tx = dlci->modem_tx;
2918 if (onoff)
2919 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2920 else
2921 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2922 if (modem_tx != dlci->modem_tx) {
2923 dlci->modem_tx = modem_tx;
2924 gsmtty_modem_update(dlci, 0);
2925 }
2926}
2927
2928static const struct tty_port_operations gsm_port_ops = {
2929 .carrier_raised = gsm_carrier_raised,
2930 .dtr_rts = gsm_dtr_rts,
2931 .destruct = gsm_dlci_free,
2932};
2933
2934static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
2935{
2936 struct gsm_mux *gsm;
2937 struct gsm_dlci *dlci;
2938 unsigned int line = tty->index;
2939 unsigned int mux = mux_line_to_num(line);
2940 bool alloc = false;
2941 int ret;
2942
2943 line = line & 0x3F;
2944
2945 if (mux >= MAX_MUX)
2946 return -ENXIO;
2947 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2948 if (gsm_mux[mux] == NULL)
2949 return -EUNATCH;
2950 if (line == 0 || line > 61) /* 62/63 reserved */
2951 return -ECHRNG;
2952 gsm = gsm_mux[mux];
2953 if (gsm->dead)
2954 return -EL2HLT;
2955 /* If DLCI 0 is not yet fully open return an error.
2956 This is ok from a locking
2957 perspective as we don't have to worry about this
2958 if DLCI0 is lost */
2959 mutex_lock(&gsm->mutex);
2960 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
2961 mutex_unlock(&gsm->mutex);
2962 return -EL2NSYNC;
2963 }
2964 dlci = gsm->dlci[line];
2965 if (dlci == NULL) {
2966 alloc = true;
2967 dlci = gsm_dlci_alloc(gsm, line);
2968 }
2969 if (dlci == NULL) {
2970 mutex_unlock(&gsm->mutex);
2971 return -ENOMEM;
2972 }
2973 ret = tty_port_install(&dlci->port, driver, tty);
2974 if (ret) {
2975 if (alloc)
2976 dlci_put(dlci);
2977 mutex_unlock(&gsm->mutex);
2978 return ret;
2979 }
2980
2981 dlci_get(dlci);
2982 dlci_get(gsm->dlci[0]);
2983 mux_get(gsm);
2984 tty->driver_data = dlci;
2985 mutex_unlock(&gsm->mutex);
2986
2987 return 0;
2988}
2989
2990static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2991{
2992 struct gsm_dlci *dlci = tty->driver_data;
2993 struct tty_port *port = &dlci->port;
2994
2995 port->count++;
2996 tty_port_tty_set(port, tty);
2997
2998 dlci->modem_rx = 0;
2999 /* We could in theory open and close before we wait - eg if we get
3000 a DM straight back. This is ok as that will have caused a hangup */
3001 tty_port_set_initialized(port, 1);
3002 /* Start sending off SABM messages */
3003 gsm_dlci_begin_open(dlci);
3004 /* And wait for virtual carrier */
3005 return tty_port_block_til_ready(port, tty, filp);
3006}
3007
3008static void gsmtty_close(struct tty_struct *tty, struct file *filp)
3009{
3010 struct gsm_dlci *dlci = tty->driver_data;
3011
3012 if (dlci == NULL)
3013 return;
3014 if (dlci->state == DLCI_CLOSED)
3015 return;
3016 mutex_lock(&dlci->mutex);
3017 gsm_destroy_network(dlci);
3018 mutex_unlock(&dlci->mutex);
3019 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
3020 return;
3021 gsm_dlci_begin_close(dlci);
3022 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
3023 tty_port_lower_dtr_rts(&dlci->port);
3024 tty_port_close_end(&dlci->port, tty);
3025 tty_port_tty_set(&dlci->port, NULL);
3026 return;
3027}
3028
3029static void gsmtty_hangup(struct tty_struct *tty)
3030{
3031 struct gsm_dlci *dlci = tty->driver_data;
3032 if (dlci->state == DLCI_CLOSED)
3033 return;
3034 tty_port_hangup(&dlci->port);
3035 gsm_dlci_begin_close(dlci);
3036}
3037
3038static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3039 int len)
3040{
3041 int sent;
3042 struct gsm_dlci *dlci = tty->driver_data;
3043 if (dlci->state == DLCI_CLOSED)
3044 return -EINVAL;
3045 /* Stuff the bytes into the fifo queue */
3046 sent = kfifo_in_locked(&dlci->fifo, buf, len, &dlci->lock);
3047 /* Need to kick the channel */
3048 gsm_dlci_data_kick(dlci);
3049 return sent;
3050}
3051
3052static int gsmtty_write_room(struct tty_struct *tty)
3053{
3054 struct gsm_dlci *dlci = tty->driver_data;
3055 if (dlci->state == DLCI_CLOSED)
3056 return -EINVAL;
3057 return TX_SIZE - kfifo_len(&dlci->fifo);
3058}
3059
3060static int gsmtty_chars_in_buffer(struct tty_struct *tty)
3061{
3062 struct gsm_dlci *dlci = tty->driver_data;
3063 if (dlci->state == DLCI_CLOSED)
3064 return -EINVAL;
3065 return kfifo_len(&dlci->fifo);
3066}
3067
3068static void gsmtty_flush_buffer(struct tty_struct *tty)
3069{
3070 struct gsm_dlci *dlci = tty->driver_data;
3071 if (dlci->state == DLCI_CLOSED)
3072 return;
3073 /* Caution needed: If we implement reliable transport classes
3074 then the data being transmitted can't simply be junked once
3075 it has first hit the stack. Until then we can just blow it
3076 away */
3077 kfifo_reset(&dlci->fifo);
3078 /* Need to unhook this DLCI from the transmit queue logic */
3079}
3080
3081static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3082{
3083 /* The FIFO handles the queue so the kernel will do the right
3084 thing waiting on chars_in_buffer before calling us. No work
3085 to do here */
3086}
3087
3088static int gsmtty_tiocmget(struct tty_struct *tty)
3089{
3090 struct gsm_dlci *dlci = tty->driver_data;
3091 if (dlci->state == DLCI_CLOSED)
3092 return -EINVAL;
3093 return dlci->modem_rx;
3094}
3095
3096static int gsmtty_tiocmset(struct tty_struct *tty,
3097 unsigned int set, unsigned int clear)
3098{
3099 struct gsm_dlci *dlci = tty->driver_data;
3100 unsigned int modem_tx = dlci->modem_tx;
3101
3102 if (dlci->state == DLCI_CLOSED)
3103 return -EINVAL;
3104 modem_tx &= ~clear;
3105 modem_tx |= set;
3106
3107 if (modem_tx != dlci->modem_tx) {
3108 dlci->modem_tx = modem_tx;
3109 return gsmtty_modem_update(dlci, 0);
3110 }
3111 return 0;
3112}
3113
3114
3115static int gsmtty_ioctl(struct tty_struct *tty,
3116 unsigned int cmd, unsigned long arg)
3117{
3118 struct gsm_dlci *dlci = tty->driver_data;
3119 struct gsm_netconfig nc;
3120 int index;
3121
3122 if (dlci->state == DLCI_CLOSED)
3123 return -EINVAL;
3124 switch (cmd) {
3125 case GSMIOC_ENABLE_NET:
3126 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3127 return -EFAULT;
3128 nc.if_name[IFNAMSIZ-1] = '\0';
3129 /* return net interface index or error code */
3130 mutex_lock(&dlci->mutex);
3131 index = gsm_create_network(dlci, &nc);
3132 mutex_unlock(&dlci->mutex);
3133 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3134 return -EFAULT;
3135 return index;
3136 case GSMIOC_DISABLE_NET:
3137 if (!capable(CAP_NET_ADMIN))
3138 return -EPERM;
3139 mutex_lock(&dlci->mutex);
3140 gsm_destroy_network(dlci);
3141 mutex_unlock(&dlci->mutex);
3142 return 0;
3143 default:
3144 return -ENOIOCTLCMD;
3145 }
3146}
3147
3148static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3149{
3150 struct gsm_dlci *dlci = tty->driver_data;
3151 if (dlci->state == DLCI_CLOSED)
3152 return;
3153 /* For the moment its fixed. In actual fact the speed information
3154 for the virtual channel can be propogated in both directions by
3155 the RPN control message. This however rapidly gets nasty as we
3156 then have to remap modem signals each way according to whether
3157 our virtual cable is null modem etc .. */
3158 tty_termios_copy_hw(&tty->termios, old);
3159}
3160
3161static void gsmtty_throttle(struct tty_struct *tty)
3162{
3163 struct gsm_dlci *dlci = tty->driver_data;
3164 if (dlci->state == DLCI_CLOSED)
3165 return;
3166 if (C_CRTSCTS(tty))
3167 dlci->modem_tx &= ~TIOCM_DTR;
3168 dlci->throttled = true;
3169 /* Send an MSC with DTR cleared */
3170 gsmtty_modem_update(dlci, 0);
3171}
3172
3173static void gsmtty_unthrottle(struct tty_struct *tty)
3174{
3175 struct gsm_dlci *dlci = tty->driver_data;
3176 if (dlci->state == DLCI_CLOSED)
3177 return;
3178 if (C_CRTSCTS(tty))
3179 dlci->modem_tx |= TIOCM_DTR;
3180 dlci->throttled = false;
3181 /* Send an MSC with DTR set */
3182 gsmtty_modem_update(dlci, 0);
3183}
3184
3185static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3186{
3187 struct gsm_dlci *dlci = tty->driver_data;
3188 int encode = 0; /* Off */
3189 if (dlci->state == DLCI_CLOSED)
3190 return -EINVAL;
3191
3192 if (state == -1) /* "On indefinitely" - we can't encode this
3193 properly */
3194 encode = 0x0F;
3195 else if (state > 0) {
3196 encode = state / 200; /* mS to encoding */
3197 if (encode > 0x0F)
3198 encode = 0x0F; /* Best effort */
3199 }
3200 return gsmtty_modem_update(dlci, encode);
3201}
3202
3203static void gsmtty_cleanup(struct tty_struct *tty)
3204{
3205 struct gsm_dlci *dlci = tty->driver_data;
3206 struct gsm_mux *gsm = dlci->gsm;
3207
3208 dlci_put(dlci);
3209 dlci_put(gsm->dlci[0]);
3210 mux_put(gsm);
3211}
3212
3213/* Virtual ttys for the demux */
3214static const struct tty_operations gsmtty_ops = {
3215 .install = gsmtty_install,
3216 .open = gsmtty_open,
3217 .close = gsmtty_close,
3218 .write = gsmtty_write,
3219 .write_room = gsmtty_write_room,
3220 .chars_in_buffer = gsmtty_chars_in_buffer,
3221 .flush_buffer = gsmtty_flush_buffer,
3222 .ioctl = gsmtty_ioctl,
3223 .throttle = gsmtty_throttle,
3224 .unthrottle = gsmtty_unthrottle,
3225 .set_termios = gsmtty_set_termios,
3226 .hangup = gsmtty_hangup,
3227 .wait_until_sent = gsmtty_wait_until_sent,
3228 .tiocmget = gsmtty_tiocmget,
3229 .tiocmset = gsmtty_tiocmset,
3230 .break_ctl = gsmtty_break_ctl,
3231 .cleanup = gsmtty_cleanup,
3232};
3233
3234
3235
3236static int __init gsm_init(void)
3237{
3238 /* Fill in our line protocol discipline, and register it */
3239 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3240 if (status != 0) {
3241 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3242 status);
3243 return status;
3244 }
3245
3246 gsm_tty_driver = alloc_tty_driver(256);
3247 if (!gsm_tty_driver) {
3248 tty_unregister_ldisc(N_GSM0710);
3249 pr_err("gsm_init: tty allocation failed.\n");
3250 return -EINVAL;
3251 }
3252 gsm_tty_driver->driver_name = "gsmtty";
3253 gsm_tty_driver->name = "gsmtty";
3254 gsm_tty_driver->major = 0; /* Dynamic */
3255 gsm_tty_driver->minor_start = 0;
3256 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3257 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3258 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3259 | TTY_DRIVER_HARDWARE_BREAK;
3260 gsm_tty_driver->init_termios = tty_std_termios;
3261 /* Fixme */
3262 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3263 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3264
3265 spin_lock_init(&gsm_mux_lock);
3266
3267 if (tty_register_driver(gsm_tty_driver)) {
3268 put_tty_driver(gsm_tty_driver);
3269 tty_unregister_ldisc(N_GSM0710);
3270 pr_err("gsm_init: tty registration failed.\n");
3271 return -EBUSY;
3272 }
3273 pr_debug("gsm_init: loaded as %d,%d.\n",
3274 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3275 return 0;
3276}
3277
3278static void __exit gsm_exit(void)
3279{
3280 int status = tty_unregister_ldisc(N_GSM0710);
3281 if (status != 0)
3282 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3283 status);
3284 tty_unregister_driver(gsm_tty_driver);
3285 put_tty_driver(gsm_tty_driver);
3286}
3287
3288module_init(gsm_init);
3289module_exit(gsm_exit);
3290
3291
3292MODULE_LICENSE("GPL");
3293MODULE_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 *
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, u8 *data, int len);
147 void (*prev_data)(struct gsm_dlci *dlci, 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, 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, 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 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, u8 *data, int clen)
1138{
1139 struct tty_port *port;
1140 unsigned int addr = 0;
1141 u8 bits;
1142 int len = clen;
1143 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 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 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, 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 /* Packetised interruptible data */
1569 case 4:
1570 break;
1571 /* Packetised uininterruptible voice/data */
1572 case 3:
1573 break;
1574 /* Asynchronous serial with line state in each frame */
1575 case 2:
1576 while (gsm_read_ea(&modem, *data++) == 0) {
1577 len--;
1578 if (len == 0)
1579 return;
1580 }
1581 tty = tty_port_tty_get(port);
1582 if (tty) {
1583 gsm_process_modem(tty, dlci, modem, clen);
1584 tty_kref_put(tty);
1585 }
1586 /* Line state will go via DLCI 0 controls only */
1587 case 1:
1588 default:
1589 tty_insert_flip_string(port, data, len);
1590 tty_flip_buffer_push(port);
1591 }
1592}
1593
1594/**
1595 * gsm_dlci_control - data arrived on control channel
1596 * @dlci: channel
1597 * @data: block of bytes received
1598 * @len: length of received block
1599 *
1600 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1601 * control channel. This should contain a command EA followed by
1602 * control data bytes. The command EA contains a command/response bit
1603 * and we divide up the work accordingly.
1604 */
1605
1606static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1607{
1608 /* See what command is involved */
1609 unsigned int command = 0;
1610 while (len-- > 0) {
1611 if (gsm_read_ea(&command, *data++) == 1) {
1612 int clen = *data++;
1613 len--;
1614 /* FIXME: this is properly an EA */
1615 clen >>= 1;
1616 /* Malformed command ? */
1617 if (clen > len)
1618 return;
1619 if (command & 1)
1620 gsm_control_message(dlci->gsm, command,
1621 data, clen);
1622 else
1623 gsm_control_response(dlci->gsm, command,
1624 data, clen);
1625 return;
1626 }
1627 }
1628}
1629
1630/*
1631 * Allocate/Free DLCI channels
1632 */
1633
1634/**
1635 * gsm_dlci_alloc - allocate a DLCI
1636 * @gsm: GSM mux
1637 * @addr: address of the DLCI
1638 *
1639 * Allocate and install a new DLCI object into the GSM mux.
1640 *
1641 * FIXME: review locking races
1642 */
1643
1644static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1645{
1646 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1647 if (dlci == NULL)
1648 return NULL;
1649 spin_lock_init(&dlci->lock);
1650 mutex_init(&dlci->mutex);
1651 dlci->fifo = &dlci->_fifo;
1652 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1653 kfree(dlci);
1654 return NULL;
1655 }
1656
1657 skb_queue_head_init(&dlci->skb_list);
1658 timer_setup(&dlci->t1, gsm_dlci_t1, 0);
1659 tty_port_init(&dlci->port);
1660 dlci->port.ops = &gsm_port_ops;
1661 dlci->gsm = gsm;
1662 dlci->addr = addr;
1663 dlci->adaption = gsm->adaption;
1664 dlci->state = DLCI_CLOSED;
1665 if (addr)
1666 dlci->data = gsm_dlci_data;
1667 else
1668 dlci->data = gsm_dlci_command;
1669 gsm->dlci[addr] = dlci;
1670 return dlci;
1671}
1672
1673/**
1674 * gsm_dlci_free - free DLCI
1675 * @dlci: DLCI to free
1676 *
1677 * Free up a DLCI.
1678 *
1679 * Can sleep.
1680 */
1681static void gsm_dlci_free(struct tty_port *port)
1682{
1683 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
1684
1685 del_timer_sync(&dlci->t1);
1686 dlci->gsm->dlci[dlci->addr] = NULL;
1687 kfifo_free(dlci->fifo);
1688 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1689 dev_kfree_skb(dlci->skb);
1690 kfree(dlci);
1691}
1692
1693static inline void dlci_get(struct gsm_dlci *dlci)
1694{
1695 tty_port_get(&dlci->port);
1696}
1697
1698static inline void dlci_put(struct gsm_dlci *dlci)
1699{
1700 tty_port_put(&dlci->port);
1701}
1702
1703static void gsm_destroy_network(struct gsm_dlci *dlci);
1704
1705/**
1706 * gsm_dlci_release - release DLCI
1707 * @dlci: DLCI to destroy
1708 *
1709 * Release a DLCI. Actual free is deferred until either
1710 * mux is closed or tty is closed - whichever is last.
1711 *
1712 * Can sleep.
1713 */
1714static void gsm_dlci_release(struct gsm_dlci *dlci)
1715{
1716 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1717 if (tty) {
1718 mutex_lock(&dlci->mutex);
1719 gsm_destroy_network(dlci);
1720 mutex_unlock(&dlci->mutex);
1721
1722 tty_vhangup(tty);
1723
1724 tty_port_tty_set(&dlci->port, NULL);
1725 tty_kref_put(tty);
1726 }
1727 dlci->state = DLCI_CLOSED;
1728 dlci_put(dlci);
1729}
1730
1731/*
1732 * LAPBish link layer logic
1733 */
1734
1735/**
1736 * gsm_queue - a GSM frame is ready to process
1737 * @gsm: pointer to our gsm mux
1738 *
1739 * At this point in time a frame has arrived and been demangled from
1740 * the line encoding. All the differences between the encodings have
1741 * been handled below us and the frame is unpacked into the structures.
1742 * The fcs holds the header FCS but any data FCS must be added here.
1743 */
1744
1745static void gsm_queue(struct gsm_mux *gsm)
1746{
1747 struct gsm_dlci *dlci;
1748 u8 cr;
1749 int address;
1750 /* We have to sneak a look at the packet body to do the FCS.
1751 A somewhat layering violation in the spec */
1752
1753 if ((gsm->control & ~PF) == UI)
1754 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1755 if (gsm->encoding == 0) {
1756 /* WARNING: gsm->received_fcs is used for
1757 gsm->encoding = 0 only.
1758 In this case it contain the last piece of data
1759 required to generate final CRC */
1760 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1761 }
1762 if (gsm->fcs != GOOD_FCS) {
1763 gsm->bad_fcs++;
1764 if (debug & 4)
1765 pr_debug("BAD FCS %02x\n", gsm->fcs);
1766 return;
1767 }
1768 address = gsm->address >> 1;
1769 if (address >= NUM_DLCI)
1770 goto invalid;
1771
1772 cr = gsm->address & 1; /* C/R bit */
1773
1774 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1775
1776 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1777 dlci = gsm->dlci[address];
1778
1779 switch (gsm->control) {
1780 case SABM|PF:
1781 if (cr == 0)
1782 goto invalid;
1783 if (dlci == NULL)
1784 dlci = gsm_dlci_alloc(gsm, address);
1785 if (dlci == NULL)
1786 return;
1787 if (dlci->dead)
1788 gsm_response(gsm, address, DM);
1789 else {
1790 gsm_response(gsm, address, UA);
1791 gsm_dlci_open(dlci);
1792 }
1793 break;
1794 case DISC|PF:
1795 if (cr == 0)
1796 goto invalid;
1797 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1798 gsm_response(gsm, address, DM);
1799 return;
1800 }
1801 /* Real close complete */
1802 gsm_response(gsm, address, UA);
1803 gsm_dlci_close(dlci);
1804 break;
1805 case UA:
1806 case UA|PF:
1807 if (cr == 0 || dlci == NULL)
1808 break;
1809 switch (dlci->state) {
1810 case DLCI_CLOSING:
1811 gsm_dlci_close(dlci);
1812 break;
1813 case DLCI_OPENING:
1814 gsm_dlci_open(dlci);
1815 break;
1816 }
1817 break;
1818 case DM: /* DM can be valid unsolicited */
1819 case DM|PF:
1820 if (cr)
1821 goto invalid;
1822 if (dlci == NULL)
1823 return;
1824 gsm_dlci_close(dlci);
1825 break;
1826 case UI:
1827 case UI|PF:
1828 case UIH:
1829 case UIH|PF:
1830#if 0
1831 if (cr)
1832 goto invalid;
1833#endif
1834 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1835 gsm_command(gsm, address, DM|PF);
1836 return;
1837 }
1838 dlci->data(dlci, gsm->buf, gsm->len);
1839 break;
1840 default:
1841 goto invalid;
1842 }
1843 return;
1844invalid:
1845 gsm->malformed++;
1846 return;
1847}
1848
1849
1850/**
1851 * gsm0_receive - perform processing for non-transparency
1852 * @gsm: gsm data for this ldisc instance
1853 * @c: character
1854 *
1855 * Receive bytes in gsm mode 0
1856 */
1857
1858static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1859{
1860 unsigned int len;
1861
1862 switch (gsm->state) {
1863 case GSM_SEARCH: /* SOF marker */
1864 if (c == GSM0_SOF) {
1865 gsm->state = GSM_ADDRESS;
1866 gsm->address = 0;
1867 gsm->len = 0;
1868 gsm->fcs = INIT_FCS;
1869 }
1870 break;
1871 case GSM_ADDRESS: /* Address EA */
1872 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1873 if (gsm_read_ea(&gsm->address, c))
1874 gsm->state = GSM_CONTROL;
1875 break;
1876 case GSM_CONTROL: /* Control Byte */
1877 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1878 gsm->control = c;
1879 gsm->state = GSM_LEN0;
1880 break;
1881 case GSM_LEN0: /* Length EA */
1882 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1883 if (gsm_read_ea(&gsm->len, c)) {
1884 if (gsm->len > gsm->mru) {
1885 gsm->bad_size++;
1886 gsm->state = GSM_SEARCH;
1887 break;
1888 }
1889 gsm->count = 0;
1890 if (!gsm->len)
1891 gsm->state = GSM_FCS;
1892 else
1893 gsm->state = GSM_DATA;
1894 break;
1895 }
1896 gsm->state = GSM_LEN1;
1897 break;
1898 case GSM_LEN1:
1899 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1900 len = c;
1901 gsm->len |= len << 7;
1902 if (gsm->len > gsm->mru) {
1903 gsm->bad_size++;
1904 gsm->state = GSM_SEARCH;
1905 break;
1906 }
1907 gsm->count = 0;
1908 if (!gsm->len)
1909 gsm->state = GSM_FCS;
1910 else
1911 gsm->state = GSM_DATA;
1912 break;
1913 case GSM_DATA: /* Data */
1914 gsm->buf[gsm->count++] = c;
1915 if (gsm->count == gsm->len)
1916 gsm->state = GSM_FCS;
1917 break;
1918 case GSM_FCS: /* FCS follows the packet */
1919 gsm->received_fcs = c;
1920 gsm_queue(gsm);
1921 gsm->state = GSM_SSOF;
1922 break;
1923 case GSM_SSOF:
1924 if (c == GSM0_SOF) {
1925 gsm->state = GSM_SEARCH;
1926 break;
1927 }
1928 break;
1929 }
1930}
1931
1932/**
1933 * gsm1_receive - perform processing for non-transparency
1934 * @gsm: gsm data for this ldisc instance
1935 * @c: character
1936 *
1937 * Receive bytes in mode 1 (Advanced option)
1938 */
1939
1940static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1941{
1942 if (c == GSM1_SOF) {
1943 /* EOF is only valid in frame if we have got to the data state
1944 and received at least one byte (the FCS) */
1945 if (gsm->state == GSM_DATA && gsm->count) {
1946 /* Extract the FCS */
1947 gsm->count--;
1948 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1949 gsm->len = gsm->count;
1950 gsm_queue(gsm);
1951 gsm->state = GSM_START;
1952 return;
1953 }
1954 /* Any partial frame was a runt so go back to start */
1955 if (gsm->state != GSM_START) {
1956 gsm->malformed++;
1957 gsm->state = GSM_START;
1958 }
1959 /* A SOF in GSM_START means we are still reading idling or
1960 framing bytes */
1961 return;
1962 }
1963
1964 if (c == GSM1_ESCAPE) {
1965 gsm->escape = 1;
1966 return;
1967 }
1968
1969 /* Only an unescaped SOF gets us out of GSM search */
1970 if (gsm->state == GSM_SEARCH)
1971 return;
1972
1973 if (gsm->escape) {
1974 c ^= GSM1_ESCAPE_BITS;
1975 gsm->escape = 0;
1976 }
1977 switch (gsm->state) {
1978 case GSM_START: /* First byte after SOF */
1979 gsm->address = 0;
1980 gsm->state = GSM_ADDRESS;
1981 gsm->fcs = INIT_FCS;
1982 /* Drop through */
1983 case GSM_ADDRESS: /* Address continuation */
1984 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1985 if (gsm_read_ea(&gsm->address, c))
1986 gsm->state = GSM_CONTROL;
1987 break;
1988 case GSM_CONTROL: /* Control Byte */
1989 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1990 gsm->control = c;
1991 gsm->count = 0;
1992 gsm->state = GSM_DATA;
1993 break;
1994 case GSM_DATA: /* Data */
1995 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
1996 gsm->state = GSM_OVERRUN;
1997 gsm->bad_size++;
1998 } else
1999 gsm->buf[gsm->count++] = c;
2000 break;
2001 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
2002 break;
2003 }
2004}
2005
2006/**
2007 * gsm_error - handle tty error
2008 * @gsm: ldisc data
2009 * @data: byte received (may be invalid)
2010 * @flag: error received
2011 *
2012 * Handle an error in the receipt of data for a frame. Currently we just
2013 * go back to hunting for a SOF.
2014 *
2015 * FIXME: better diagnostics ?
2016 */
2017
2018static void gsm_error(struct gsm_mux *gsm,
2019 unsigned char data, unsigned char flag)
2020{
2021 gsm->state = GSM_SEARCH;
2022 gsm->io_error++;
2023}
2024
2025static int gsm_disconnect(struct gsm_mux *gsm)
2026{
2027 struct gsm_dlci *dlci = gsm->dlci[0];
2028 struct gsm_control *gc;
2029
2030 if (!dlci)
2031 return 0;
2032
2033 /* In theory disconnecting DLCI 0 is sufficient but for some
2034 modems this is apparently not the case. */
2035 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2036 if (gc)
2037 gsm_control_wait(gsm, gc);
2038
2039 del_timer_sync(&gsm->t2_timer);
2040 /* Now we are sure T2 has stopped */
2041
2042 gsm_dlci_begin_close(dlci);
2043 wait_event_interruptible(gsm->event,
2044 dlci->state == DLCI_CLOSED);
2045
2046 if (signal_pending(current))
2047 return -EINTR;
2048
2049 return 0;
2050}
2051
2052/**
2053 * gsm_cleanup_mux - generic GSM protocol cleanup
2054 * @gsm: our mux
2055 *
2056 * Clean up the bits of the mux which are the same for all framing
2057 * protocols. Remove the mux from the mux table, stop all the timers
2058 * and then shut down each device hanging up the channels as we go.
2059 */
2060
2061static void gsm_cleanup_mux(struct gsm_mux *gsm)
2062{
2063 int i;
2064 struct gsm_dlci *dlci = gsm->dlci[0];
2065 struct gsm_msg *txq, *ntxq;
2066
2067 gsm->dead = 1;
2068
2069 spin_lock(&gsm_mux_lock);
2070 for (i = 0; i < MAX_MUX; i++) {
2071 if (gsm_mux[i] == gsm) {
2072 gsm_mux[i] = NULL;
2073 break;
2074 }
2075 }
2076 spin_unlock(&gsm_mux_lock);
2077 /* open failed before registering => nothing to do */
2078 if (i == MAX_MUX)
2079 return;
2080
2081 del_timer_sync(&gsm->t2_timer);
2082 /* Now we are sure T2 has stopped */
2083 if (dlci)
2084 dlci->dead = 1;
2085
2086 /* Free up any link layer users */
2087 mutex_lock(&gsm->mutex);
2088 for (i = 0; i < NUM_DLCI; i++)
2089 if (gsm->dlci[i])
2090 gsm_dlci_release(gsm->dlci[i]);
2091 mutex_unlock(&gsm->mutex);
2092 /* Now wipe the queues */
2093 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2094 kfree(txq);
2095 INIT_LIST_HEAD(&gsm->tx_list);
2096}
2097
2098/**
2099 * gsm_activate_mux - generic GSM setup
2100 * @gsm: our mux
2101 *
2102 * Set up the bits of the mux which are the same for all framing
2103 * protocols. Add the mux to the mux table so it can be opened and
2104 * finally kick off connecting to DLCI 0 on the modem.
2105 */
2106
2107static int gsm_activate_mux(struct gsm_mux *gsm)
2108{
2109 struct gsm_dlci *dlci;
2110 int i = 0;
2111
2112 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
2113 init_waitqueue_head(&gsm->event);
2114 spin_lock_init(&gsm->control_lock);
2115 spin_lock_init(&gsm->tx_lock);
2116
2117 if (gsm->encoding == 0)
2118 gsm->receive = gsm0_receive;
2119 else
2120 gsm->receive = gsm1_receive;
2121 gsm->error = gsm_error;
2122
2123 spin_lock(&gsm_mux_lock);
2124 for (i = 0; i < MAX_MUX; i++) {
2125 if (gsm_mux[i] == NULL) {
2126 gsm->num = i;
2127 gsm_mux[i] = gsm;
2128 break;
2129 }
2130 }
2131 spin_unlock(&gsm_mux_lock);
2132 if (i == MAX_MUX)
2133 return -EBUSY;
2134
2135 dlci = gsm_dlci_alloc(gsm, 0);
2136 if (dlci == NULL)
2137 return -ENOMEM;
2138 gsm->dead = 0; /* Tty opens are now permissible */
2139 return 0;
2140}
2141
2142/**
2143 * gsm_free_mux - free up a mux
2144 * @mux: mux to free
2145 *
2146 * Dispose of allocated resources for a dead mux
2147 */
2148static void gsm_free_mux(struct gsm_mux *gsm)
2149{
2150 kfree(gsm->txframe);
2151 kfree(gsm->buf);
2152 kfree(gsm);
2153}
2154
2155/**
2156 * gsm_free_muxr - free up a mux
2157 * @mux: mux to free
2158 *
2159 * Dispose of allocated resources for a dead mux
2160 */
2161static void gsm_free_muxr(struct kref *ref)
2162{
2163 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2164 gsm_free_mux(gsm);
2165}
2166
2167static inline void mux_get(struct gsm_mux *gsm)
2168{
2169 kref_get(&gsm->ref);
2170}
2171
2172static inline void mux_put(struct gsm_mux *gsm)
2173{
2174 kref_put(&gsm->ref, gsm_free_muxr);
2175}
2176
2177/**
2178 * gsm_alloc_mux - allocate a mux
2179 *
2180 * Creates a new mux ready for activation.
2181 */
2182
2183static struct gsm_mux *gsm_alloc_mux(void)
2184{
2185 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2186 if (gsm == NULL)
2187 return NULL;
2188 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2189 if (gsm->buf == NULL) {
2190 kfree(gsm);
2191 return NULL;
2192 }
2193 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2194 if (gsm->txframe == NULL) {
2195 kfree(gsm->buf);
2196 kfree(gsm);
2197 return NULL;
2198 }
2199 spin_lock_init(&gsm->lock);
2200 mutex_init(&gsm->mutex);
2201 kref_init(&gsm->ref);
2202 INIT_LIST_HEAD(&gsm->tx_list);
2203
2204 gsm->t1 = T1;
2205 gsm->t2 = T2;
2206 gsm->n2 = N2;
2207 gsm->ftype = UIH;
2208 gsm->adaption = 1;
2209 gsm->encoding = 1;
2210 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2211 gsm->mtu = 64;
2212 gsm->dead = 1; /* Avoid early tty opens */
2213
2214 return gsm;
2215}
2216
2217/**
2218 * gsmld_output - write to link
2219 * @gsm: our mux
2220 * @data: bytes to output
2221 * @len: size
2222 *
2223 * Write a block of data from the GSM mux to the data channel. This
2224 * will eventually be serialized from above but at the moment isn't.
2225 */
2226
2227static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2228{
2229 if (tty_write_room(gsm->tty) < len) {
2230 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2231 return -ENOSPC;
2232 }
2233 if (debug & 4)
2234 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2235 data, len);
2236 gsm->tty->ops->write(gsm->tty, data, len);
2237 return len;
2238}
2239
2240/**
2241 * gsmld_attach_gsm - mode set up
2242 * @tty: our tty structure
2243 * @gsm: our mux
2244 *
2245 * Set up the MUX for basic mode and commence connecting to the
2246 * modem. Currently called from the line discipline set up but
2247 * will need moving to an ioctl path.
2248 */
2249
2250static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2251{
2252 int ret, i, base;
2253
2254 gsm->tty = tty_kref_get(tty);
2255 gsm->output = gsmld_output;
2256 ret = gsm_activate_mux(gsm);
2257 if (ret != 0)
2258 tty_kref_put(gsm->tty);
2259 else {
2260 /* Don't register device 0 - this is the control channel and not
2261 a usable tty interface */
2262 base = gsm->num << 6; /* Base for this MUX */
2263 for (i = 1; i < NUM_DLCI; i++)
2264 tty_register_device(gsm_tty_driver, base + i, NULL);
2265 }
2266 return ret;
2267}
2268
2269
2270/**
2271 * gsmld_detach_gsm - stop doing 0710 mux
2272 * @tty: tty attached to the mux
2273 * @gsm: mux
2274 *
2275 * Shutdown and then clean up the resources used by the line discipline
2276 */
2277
2278static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2279{
2280 int i;
2281 int base = gsm->num << 6; /* Base for this MUX */
2282
2283 WARN_ON(tty != gsm->tty);
2284 for (i = 1; i < NUM_DLCI; i++)
2285 tty_unregister_device(gsm_tty_driver, base + i);
2286 gsm_cleanup_mux(gsm);
2287 tty_kref_put(gsm->tty);
2288 gsm->tty = NULL;
2289}
2290
2291static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2292 char *fp, int count)
2293{
2294 struct gsm_mux *gsm = tty->disc_data;
2295 const unsigned char *dp;
2296 char *f;
2297 int i;
2298 char flags = TTY_NORMAL;
2299
2300 if (debug & 4)
2301 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2302 cp, count);
2303
2304 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2305 if (f)
2306 flags = *f++;
2307 switch (flags) {
2308 case TTY_NORMAL:
2309 gsm->receive(gsm, *dp);
2310 break;
2311 case TTY_OVERRUN:
2312 case TTY_BREAK:
2313 case TTY_PARITY:
2314 case TTY_FRAME:
2315 gsm->error(gsm, *dp, flags);
2316 break;
2317 default:
2318 WARN_ONCE(1, "%s: unknown flag %d\n",
2319 tty_name(tty), flags);
2320 break;
2321 }
2322 }
2323 /* FASYNC if needed ? */
2324 /* If clogged call tty_throttle(tty); */
2325}
2326
2327/**
2328 * gsmld_flush_buffer - clean input queue
2329 * @tty: terminal device
2330 *
2331 * Flush the input buffer. Called when the line discipline is
2332 * being closed, when the tty layer wants the buffer flushed (eg
2333 * at hangup).
2334 */
2335
2336static void gsmld_flush_buffer(struct tty_struct *tty)
2337{
2338}
2339
2340/**
2341 * gsmld_close - close the ldisc for this tty
2342 * @tty: device
2343 *
2344 * Called from the terminal layer when this line discipline is
2345 * being shut down, either because of a close or becsuse of a
2346 * discipline change. The function will not be called while other
2347 * ldisc methods are in progress.
2348 */
2349
2350static void gsmld_close(struct tty_struct *tty)
2351{
2352 struct gsm_mux *gsm = tty->disc_data;
2353
2354 gsmld_detach_gsm(tty, gsm);
2355
2356 gsmld_flush_buffer(tty);
2357 /* Do other clean up here */
2358 mux_put(gsm);
2359}
2360
2361/**
2362 * gsmld_open - open an ldisc
2363 * @tty: terminal to open
2364 *
2365 * Called when this line discipline is being attached to the
2366 * terminal device. Can sleep. Called serialized so that no
2367 * other events will occur in parallel. No further open will occur
2368 * until a close.
2369 */
2370
2371static int gsmld_open(struct tty_struct *tty)
2372{
2373 struct gsm_mux *gsm;
2374 int ret;
2375
2376 if (tty->ops->write == NULL)
2377 return -EINVAL;
2378
2379 /* Attach our ldisc data */
2380 gsm = gsm_alloc_mux();
2381 if (gsm == NULL)
2382 return -ENOMEM;
2383
2384 tty->disc_data = gsm;
2385 tty->receive_room = 65536;
2386
2387 /* Attach the initial passive connection */
2388 gsm->encoding = 1;
2389
2390 ret = gsmld_attach_gsm(tty, gsm);
2391 if (ret != 0) {
2392 gsm_cleanup_mux(gsm);
2393 mux_put(gsm);
2394 }
2395 return ret;
2396}
2397
2398/**
2399 * gsmld_write_wakeup - asynchronous I/O notifier
2400 * @tty: tty device
2401 *
2402 * Required for the ptys, serial driver etc. since processes
2403 * that attach themselves to the master and rely on ASYNC
2404 * IO must be woken up
2405 */
2406
2407static void gsmld_write_wakeup(struct tty_struct *tty)
2408{
2409 struct gsm_mux *gsm = tty->disc_data;
2410 unsigned long flags;
2411
2412 /* Queue poll */
2413 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2414 spin_lock_irqsave(&gsm->tx_lock, flags);
2415 gsm_data_kick(gsm);
2416 if (gsm->tx_bytes < TX_THRESH_LO) {
2417 gsm_dlci_data_sweep(gsm);
2418 }
2419 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2420}
2421
2422/**
2423 * gsmld_read - read function for tty
2424 * @tty: tty device
2425 * @file: file object
2426 * @buf: userspace buffer pointer
2427 * @nr: size of I/O
2428 *
2429 * Perform reads for the line discipline. We are guaranteed that the
2430 * line discipline will not be closed under us but we may get multiple
2431 * parallel readers and must handle this ourselves. We may also get
2432 * a hangup. Always called in user context, may sleep.
2433 *
2434 * This code must be sure never to sleep through a hangup.
2435 */
2436
2437static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2438 unsigned char __user *buf, size_t nr)
2439{
2440 return -EOPNOTSUPP;
2441}
2442
2443/**
2444 * gsmld_write - write function for tty
2445 * @tty: tty device
2446 * @file: file object
2447 * @buf: userspace buffer pointer
2448 * @nr: size of I/O
2449 *
2450 * Called when the owner of the device wants to send a frame
2451 * itself (or some other control data). The data is transferred
2452 * as-is and must be properly framed and checksummed as appropriate
2453 * by userspace. Frames are either sent whole or not at all as this
2454 * avoids pain user side.
2455 */
2456
2457static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2458 const unsigned char *buf, size_t nr)
2459{
2460 int space = tty_write_room(tty);
2461 if (space >= nr)
2462 return tty->ops->write(tty, buf, nr);
2463 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2464 return -ENOBUFS;
2465}
2466
2467/**
2468 * gsmld_poll - poll method for N_GSM0710
2469 * @tty: terminal device
2470 * @file: file accessing it
2471 * @wait: poll table
2472 *
2473 * Called when the line discipline is asked to poll() for data or
2474 * for special events. This code is not serialized with respect to
2475 * other events save open/close.
2476 *
2477 * This code must be sure never to sleep through a hangup.
2478 * Called without the kernel lock held - fine
2479 */
2480
2481static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
2482 poll_table *wait)
2483{
2484 __poll_t mask = 0;
2485 struct gsm_mux *gsm = tty->disc_data;
2486
2487 poll_wait(file, &tty->read_wait, wait);
2488 poll_wait(file, &tty->write_wait, wait);
2489 if (tty_hung_up_p(file))
2490 mask |= EPOLLHUP;
2491 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2492 mask |= EPOLLOUT | EPOLLWRNORM;
2493 if (gsm->dead)
2494 mask |= EPOLLHUP;
2495 return mask;
2496}
2497
2498static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2499 struct gsm_config *c)
2500{
2501 int need_close = 0;
2502 int need_restart = 0;
2503
2504 /* Stuff we don't support yet - UI or I frame transport, windowing */
2505 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2506 return -EOPNOTSUPP;
2507 /* Check the MRU/MTU range looks sane */
2508 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2509 return -EINVAL;
2510 if (c->n2 < 3)
2511 return -EINVAL;
2512 if (c->encapsulation > 1) /* Basic, advanced, no I */
2513 return -EINVAL;
2514 if (c->initiator > 1)
2515 return -EINVAL;
2516 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2517 return -EINVAL;
2518 /*
2519 * See what is needed for reconfiguration
2520 */
2521
2522 /* Timing fields */
2523 if (c->t1 != 0 && c->t1 != gsm->t1)
2524 need_restart = 1;
2525 if (c->t2 != 0 && c->t2 != gsm->t2)
2526 need_restart = 1;
2527 if (c->encapsulation != gsm->encoding)
2528 need_restart = 1;
2529 if (c->adaption != gsm->adaption)
2530 need_restart = 1;
2531 /* Requires care */
2532 if (c->initiator != gsm->initiator)
2533 need_close = 1;
2534 if (c->mru != gsm->mru)
2535 need_restart = 1;
2536 if (c->mtu != gsm->mtu)
2537 need_restart = 1;
2538
2539 /*
2540 * Close down what is needed, restart and initiate the new
2541 * configuration
2542 */
2543
2544 if (need_close || need_restart) {
2545 int ret;
2546
2547 ret = gsm_disconnect(gsm);
2548
2549 if (ret)
2550 return ret;
2551 }
2552 if (need_restart)
2553 gsm_cleanup_mux(gsm);
2554
2555 gsm->initiator = c->initiator;
2556 gsm->mru = c->mru;
2557 gsm->mtu = c->mtu;
2558 gsm->encoding = c->encapsulation;
2559 gsm->adaption = c->adaption;
2560 gsm->n2 = c->n2;
2561
2562 if (c->i == 1)
2563 gsm->ftype = UIH;
2564 else if (c->i == 2)
2565 gsm->ftype = UI;
2566
2567 if (c->t1)
2568 gsm->t1 = c->t1;
2569 if (c->t2)
2570 gsm->t2 = c->t2;
2571
2572 /* FIXME: We need to separate activation/deactivation from adding
2573 and removing from the mux array */
2574 if (need_restart)
2575 gsm_activate_mux(gsm);
2576 if (gsm->initiator && need_close)
2577 gsm_dlci_begin_open(gsm->dlci[0]);
2578 return 0;
2579}
2580
2581static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2582 unsigned int cmd, unsigned long arg)
2583{
2584 struct gsm_config c;
2585 struct gsm_mux *gsm = tty->disc_data;
2586
2587 switch (cmd) {
2588 case GSMIOC_GETCONF:
2589 memset(&c, 0, sizeof(c));
2590 c.adaption = gsm->adaption;
2591 c.encapsulation = gsm->encoding;
2592 c.initiator = gsm->initiator;
2593 c.t1 = gsm->t1;
2594 c.t2 = gsm->t2;
2595 c.t3 = 0; /* Not supported */
2596 c.n2 = gsm->n2;
2597 if (gsm->ftype == UIH)
2598 c.i = 1;
2599 else
2600 c.i = 2;
2601 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
2602 c.mru = gsm->mru;
2603 c.mtu = gsm->mtu;
2604 c.k = 0;
2605 if (copy_to_user((void *)arg, &c, sizeof(c)))
2606 return -EFAULT;
2607 return 0;
2608 case GSMIOC_SETCONF:
2609 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2610 return -EFAULT;
2611 return gsmld_config(tty, gsm, &c);
2612 default:
2613 return n_tty_ioctl_helper(tty, file, cmd, arg);
2614 }
2615}
2616
2617#ifdef CONFIG_COMPAT
2618static long gsmld_compat_ioctl(struct tty_struct *tty, struct file *file,
2619 unsigned int cmd, unsigned long arg)
2620{
2621 return gsmld_ioctl(tty, file, cmd, arg);
2622}
2623#endif
2624
2625/*
2626 * Network interface
2627 *
2628 */
2629
2630static int gsm_mux_net_open(struct net_device *net)
2631{
2632 pr_debug("%s called\n", __func__);
2633 netif_start_queue(net);
2634 return 0;
2635}
2636
2637static int gsm_mux_net_close(struct net_device *net)
2638{
2639 netif_stop_queue(net);
2640 return 0;
2641}
2642
2643static void dlci_net_free(struct gsm_dlci *dlci)
2644{
2645 if (!dlci->net) {
2646 WARN_ON(1);
2647 return;
2648 }
2649 dlci->adaption = dlci->prev_adaption;
2650 dlci->data = dlci->prev_data;
2651 free_netdev(dlci->net);
2652 dlci->net = NULL;
2653}
2654static void net_free(struct kref *ref)
2655{
2656 struct gsm_mux_net *mux_net;
2657 struct gsm_dlci *dlci;
2658
2659 mux_net = container_of(ref, struct gsm_mux_net, ref);
2660 dlci = mux_net->dlci;
2661
2662 if (dlci->net) {
2663 unregister_netdev(dlci->net);
2664 dlci_net_free(dlci);
2665 }
2666}
2667
2668static inline void muxnet_get(struct gsm_mux_net *mux_net)
2669{
2670 kref_get(&mux_net->ref);
2671}
2672
2673static inline void muxnet_put(struct gsm_mux_net *mux_net)
2674{
2675 kref_put(&mux_net->ref, net_free);
2676}
2677
2678static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2679 struct net_device *net)
2680{
2681 struct gsm_mux_net *mux_net = netdev_priv(net);
2682 struct gsm_dlci *dlci = mux_net->dlci;
2683 muxnet_get(mux_net);
2684
2685 skb_queue_head(&dlci->skb_list, skb);
2686 net->stats.tx_packets++;
2687 net->stats.tx_bytes += skb->len;
2688 gsm_dlci_data_kick(dlci);
2689 /* And tell the kernel when the last transmit started. */
2690 netif_trans_update(net);
2691 muxnet_put(mux_net);
2692 return NETDEV_TX_OK;
2693}
2694
2695/* called when a packet did not ack after watchdogtimeout */
2696static void gsm_mux_net_tx_timeout(struct net_device *net)
2697{
2698 /* Tell syslog we are hosed. */
2699 dev_dbg(&net->dev, "Tx timed out.\n");
2700
2701 /* Update statistics */
2702 net->stats.tx_errors++;
2703}
2704
2705static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2706 unsigned char *in_buf, int size)
2707{
2708 struct net_device *net = dlci->net;
2709 struct sk_buff *skb;
2710 struct gsm_mux_net *mux_net = netdev_priv(net);
2711 muxnet_get(mux_net);
2712
2713 /* Allocate an sk_buff */
2714 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2715 if (!skb) {
2716 /* We got no receive buffer. */
2717 net->stats.rx_dropped++;
2718 muxnet_put(mux_net);
2719 return;
2720 }
2721 skb_reserve(skb, NET_IP_ALIGN);
2722 skb_put_data(skb, in_buf, size);
2723
2724 skb->dev = net;
2725 skb->protocol = htons(ETH_P_IP);
2726
2727 /* Ship it off to the kernel */
2728 netif_rx(skb);
2729
2730 /* update out statistics */
2731 net->stats.rx_packets++;
2732 net->stats.rx_bytes += size;
2733 muxnet_put(mux_net);
2734 return;
2735}
2736
2737static void gsm_mux_net_init(struct net_device *net)
2738{
2739 static const struct net_device_ops gsm_netdev_ops = {
2740 .ndo_open = gsm_mux_net_open,
2741 .ndo_stop = gsm_mux_net_close,
2742 .ndo_start_xmit = gsm_mux_net_start_xmit,
2743 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2744 };
2745
2746 net->netdev_ops = &gsm_netdev_ops;
2747
2748 /* fill in the other fields */
2749 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2750 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2751 net->type = ARPHRD_NONE;
2752 net->tx_queue_len = 10;
2753}
2754
2755
2756/* caller holds the dlci mutex */
2757static void gsm_destroy_network(struct gsm_dlci *dlci)
2758{
2759 struct gsm_mux_net *mux_net;
2760
2761 pr_debug("destroy network interface");
2762 if (!dlci->net)
2763 return;
2764 mux_net = netdev_priv(dlci->net);
2765 muxnet_put(mux_net);
2766}
2767
2768
2769/* caller holds the dlci mutex */
2770static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2771{
2772 char *netname;
2773 int retval = 0;
2774 struct net_device *net;
2775 struct gsm_mux_net *mux_net;
2776
2777 if (!capable(CAP_NET_ADMIN))
2778 return -EPERM;
2779
2780 /* Already in a non tty mode */
2781 if (dlci->adaption > 2)
2782 return -EBUSY;
2783
2784 if (nc->protocol != htons(ETH_P_IP))
2785 return -EPROTONOSUPPORT;
2786
2787 if (nc->adaption != 3 && nc->adaption != 4)
2788 return -EPROTONOSUPPORT;
2789
2790 pr_debug("create network interface");
2791
2792 netname = "gsm%d";
2793 if (nc->if_name[0] != '\0')
2794 netname = nc->if_name;
2795 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
2796 NET_NAME_UNKNOWN, gsm_mux_net_init);
2797 if (!net) {
2798 pr_err("alloc_netdev failed");
2799 return -ENOMEM;
2800 }
2801 net->mtu = dlci->gsm->mtu;
2802 net->min_mtu = 8;
2803 net->max_mtu = dlci->gsm->mtu;
2804 mux_net = netdev_priv(net);
2805 mux_net->dlci = dlci;
2806 kref_init(&mux_net->ref);
2807 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2808
2809 /* reconfigure dlci for network */
2810 dlci->prev_adaption = dlci->adaption;
2811 dlci->prev_data = dlci->data;
2812 dlci->adaption = nc->adaption;
2813 dlci->data = gsm_mux_rx_netchar;
2814 dlci->net = net;
2815
2816 pr_debug("register netdev");
2817 retval = register_netdev(net);
2818 if (retval) {
2819 pr_err("network register fail %d\n", retval);
2820 dlci_net_free(dlci);
2821 return retval;
2822 }
2823 return net->ifindex; /* return network index */
2824}
2825
2826/* Line discipline for real tty */
2827static struct tty_ldisc_ops tty_ldisc_packet = {
2828 .owner = THIS_MODULE,
2829 .magic = TTY_LDISC_MAGIC,
2830 .name = "n_gsm",
2831 .open = gsmld_open,
2832 .close = gsmld_close,
2833 .flush_buffer = gsmld_flush_buffer,
2834 .read = gsmld_read,
2835 .write = gsmld_write,
2836#ifdef CONFIG_COMPAT
2837 .compat_ioctl = gsmld_compat_ioctl,
2838#endif
2839 .ioctl = gsmld_ioctl,
2840 .poll = gsmld_poll,
2841 .receive_buf = gsmld_receive_buf,
2842 .write_wakeup = gsmld_write_wakeup
2843};
2844
2845/*
2846 * Virtual tty side
2847 */
2848
2849#define TX_SIZE 512
2850
2851static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2852{
2853 u8 modembits[5];
2854 struct gsm_control *ctrl;
2855 int len = 2;
2856
2857 if (brk)
2858 len++;
2859
2860 modembits[0] = len << 1 | EA; /* Data bytes */
2861 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2862 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2863 if (brk)
2864 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2865 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2866 if (ctrl == NULL)
2867 return -ENOMEM;
2868 return gsm_control_wait(dlci->gsm, ctrl);
2869}
2870
2871static int gsm_carrier_raised(struct tty_port *port)
2872{
2873 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2874 struct gsm_mux *gsm = dlci->gsm;
2875
2876 /* Not yet open so no carrier info */
2877 if (dlci->state != DLCI_OPEN)
2878 return 0;
2879 if (debug & 2)
2880 return 1;
2881
2882 /*
2883 * Basic mode with control channel in ADM mode may not respond
2884 * to CMD_MSC at all and modem_rx is empty.
2885 */
2886 if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM &&
2887 !dlci->modem_rx)
2888 return 1;
2889
2890 return dlci->modem_rx & TIOCM_CD;
2891}
2892
2893static void gsm_dtr_rts(struct tty_port *port, int onoff)
2894{
2895 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2896 unsigned int modem_tx = dlci->modem_tx;
2897 if (onoff)
2898 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2899 else
2900 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2901 if (modem_tx != dlci->modem_tx) {
2902 dlci->modem_tx = modem_tx;
2903 gsmtty_modem_update(dlci, 0);
2904 }
2905}
2906
2907static const struct tty_port_operations gsm_port_ops = {
2908 .carrier_raised = gsm_carrier_raised,
2909 .dtr_rts = gsm_dtr_rts,
2910 .destruct = gsm_dlci_free,
2911};
2912
2913static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
2914{
2915 struct gsm_mux *gsm;
2916 struct gsm_dlci *dlci;
2917 unsigned int line = tty->index;
2918 unsigned int mux = line >> 6;
2919 bool alloc = false;
2920 int ret;
2921
2922 line = line & 0x3F;
2923
2924 if (mux >= MAX_MUX)
2925 return -ENXIO;
2926 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2927 if (gsm_mux[mux] == NULL)
2928 return -EUNATCH;
2929 if (line == 0 || line > 61) /* 62/63 reserved */
2930 return -ECHRNG;
2931 gsm = gsm_mux[mux];
2932 if (gsm->dead)
2933 return -EL2HLT;
2934 /* If DLCI 0 is not yet fully open return an error.
2935 This is ok from a locking
2936 perspective as we don't have to worry about this
2937 if DLCI0 is lost */
2938 mutex_lock(&gsm->mutex);
2939 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
2940 mutex_unlock(&gsm->mutex);
2941 return -EL2NSYNC;
2942 }
2943 dlci = gsm->dlci[line];
2944 if (dlci == NULL) {
2945 alloc = true;
2946 dlci = gsm_dlci_alloc(gsm, line);
2947 }
2948 if (dlci == NULL) {
2949 mutex_unlock(&gsm->mutex);
2950 return -ENOMEM;
2951 }
2952 ret = tty_port_install(&dlci->port, driver, tty);
2953 if (ret) {
2954 if (alloc)
2955 dlci_put(dlci);
2956 mutex_unlock(&gsm->mutex);
2957 return ret;
2958 }
2959
2960 dlci_get(dlci);
2961 dlci_get(gsm->dlci[0]);
2962 mux_get(gsm);
2963 tty->driver_data = dlci;
2964 mutex_unlock(&gsm->mutex);
2965
2966 return 0;
2967}
2968
2969static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2970{
2971 struct gsm_dlci *dlci = tty->driver_data;
2972 struct tty_port *port = &dlci->port;
2973
2974 port->count++;
2975 tty_port_tty_set(port, tty);
2976
2977 dlci->modem_rx = 0;
2978 /* We could in theory open and close before we wait - eg if we get
2979 a DM straight back. This is ok as that will have caused a hangup */
2980 tty_port_set_initialized(port, 1);
2981 /* Start sending off SABM messages */
2982 gsm_dlci_begin_open(dlci);
2983 /* And wait for virtual carrier */
2984 return tty_port_block_til_ready(port, tty, filp);
2985}
2986
2987static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2988{
2989 struct gsm_dlci *dlci = tty->driver_data;
2990
2991 if (dlci == NULL)
2992 return;
2993 if (dlci->state == DLCI_CLOSED)
2994 return;
2995 mutex_lock(&dlci->mutex);
2996 gsm_destroy_network(dlci);
2997 mutex_unlock(&dlci->mutex);
2998 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
2999 return;
3000 gsm_dlci_begin_close(dlci);
3001 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
3002 tty_port_lower_dtr_rts(&dlci->port);
3003 tty_port_close_end(&dlci->port, tty);
3004 tty_port_tty_set(&dlci->port, NULL);
3005 return;
3006}
3007
3008static void gsmtty_hangup(struct tty_struct *tty)
3009{
3010 struct gsm_dlci *dlci = tty->driver_data;
3011 if (dlci->state == DLCI_CLOSED)
3012 return;
3013 tty_port_hangup(&dlci->port);
3014 gsm_dlci_begin_close(dlci);
3015}
3016
3017static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3018 int len)
3019{
3020 int sent;
3021 struct gsm_dlci *dlci = tty->driver_data;
3022 if (dlci->state == DLCI_CLOSED)
3023 return -EINVAL;
3024 /* Stuff the bytes into the fifo queue */
3025 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
3026 /* Need to kick the channel */
3027 gsm_dlci_data_kick(dlci);
3028 return sent;
3029}
3030
3031static int gsmtty_write_room(struct tty_struct *tty)
3032{
3033 struct gsm_dlci *dlci = tty->driver_data;
3034 if (dlci->state == DLCI_CLOSED)
3035 return -EINVAL;
3036 return TX_SIZE - kfifo_len(dlci->fifo);
3037}
3038
3039static int gsmtty_chars_in_buffer(struct tty_struct *tty)
3040{
3041 struct gsm_dlci *dlci = tty->driver_data;
3042 if (dlci->state == DLCI_CLOSED)
3043 return -EINVAL;
3044 return kfifo_len(dlci->fifo);
3045}
3046
3047static void gsmtty_flush_buffer(struct tty_struct *tty)
3048{
3049 struct gsm_dlci *dlci = tty->driver_data;
3050 if (dlci->state == DLCI_CLOSED)
3051 return;
3052 /* Caution needed: If we implement reliable transport classes
3053 then the data being transmitted can't simply be junked once
3054 it has first hit the stack. Until then we can just blow it
3055 away */
3056 kfifo_reset(dlci->fifo);
3057 /* Need to unhook this DLCI from the transmit queue logic */
3058}
3059
3060static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3061{
3062 /* The FIFO handles the queue so the kernel will do the right
3063 thing waiting on chars_in_buffer before calling us. No work
3064 to do here */
3065}
3066
3067static int gsmtty_tiocmget(struct tty_struct *tty)
3068{
3069 struct gsm_dlci *dlci = tty->driver_data;
3070 if (dlci->state == DLCI_CLOSED)
3071 return -EINVAL;
3072 return dlci->modem_rx;
3073}
3074
3075static int gsmtty_tiocmset(struct tty_struct *tty,
3076 unsigned int set, unsigned int clear)
3077{
3078 struct gsm_dlci *dlci = tty->driver_data;
3079 unsigned int modem_tx = dlci->modem_tx;
3080
3081 if (dlci->state == DLCI_CLOSED)
3082 return -EINVAL;
3083 modem_tx &= ~clear;
3084 modem_tx |= set;
3085
3086 if (modem_tx != dlci->modem_tx) {
3087 dlci->modem_tx = modem_tx;
3088 return gsmtty_modem_update(dlci, 0);
3089 }
3090 return 0;
3091}
3092
3093
3094static int gsmtty_ioctl(struct tty_struct *tty,
3095 unsigned int cmd, unsigned long arg)
3096{
3097 struct gsm_dlci *dlci = tty->driver_data;
3098 struct gsm_netconfig nc;
3099 int index;
3100
3101 if (dlci->state == DLCI_CLOSED)
3102 return -EINVAL;
3103 switch (cmd) {
3104 case GSMIOC_ENABLE_NET:
3105 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3106 return -EFAULT;
3107 nc.if_name[IFNAMSIZ-1] = '\0';
3108 /* return net interface index or error code */
3109 mutex_lock(&dlci->mutex);
3110 index = gsm_create_network(dlci, &nc);
3111 mutex_unlock(&dlci->mutex);
3112 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3113 return -EFAULT;
3114 return index;
3115 case GSMIOC_DISABLE_NET:
3116 if (!capable(CAP_NET_ADMIN))
3117 return -EPERM;
3118 mutex_lock(&dlci->mutex);
3119 gsm_destroy_network(dlci);
3120 mutex_unlock(&dlci->mutex);
3121 return 0;
3122 default:
3123 return -ENOIOCTLCMD;
3124 }
3125}
3126
3127static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3128{
3129 struct gsm_dlci *dlci = tty->driver_data;
3130 if (dlci->state == DLCI_CLOSED)
3131 return;
3132 /* For the moment its fixed. In actual fact the speed information
3133 for the virtual channel can be propogated in both directions by
3134 the RPN control message. This however rapidly gets nasty as we
3135 then have to remap modem signals each way according to whether
3136 our virtual cable is null modem etc .. */
3137 tty_termios_copy_hw(&tty->termios, old);
3138}
3139
3140static void gsmtty_throttle(struct tty_struct *tty)
3141{
3142 struct gsm_dlci *dlci = tty->driver_data;
3143 if (dlci->state == DLCI_CLOSED)
3144 return;
3145 if (C_CRTSCTS(tty))
3146 dlci->modem_tx &= ~TIOCM_DTR;
3147 dlci->throttled = 1;
3148 /* Send an MSC with DTR cleared */
3149 gsmtty_modem_update(dlci, 0);
3150}
3151
3152static void gsmtty_unthrottle(struct tty_struct *tty)
3153{
3154 struct gsm_dlci *dlci = tty->driver_data;
3155 if (dlci->state == DLCI_CLOSED)
3156 return;
3157 if (C_CRTSCTS(tty))
3158 dlci->modem_tx |= TIOCM_DTR;
3159 dlci->throttled = 0;
3160 /* Send an MSC with DTR set */
3161 gsmtty_modem_update(dlci, 0);
3162}
3163
3164static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3165{
3166 struct gsm_dlci *dlci = tty->driver_data;
3167 int encode = 0; /* Off */
3168 if (dlci->state == DLCI_CLOSED)
3169 return -EINVAL;
3170
3171 if (state == -1) /* "On indefinitely" - we can't encode this
3172 properly */
3173 encode = 0x0F;
3174 else if (state > 0) {
3175 encode = state / 200; /* mS to encoding */
3176 if (encode > 0x0F)
3177 encode = 0x0F; /* Best effort */
3178 }
3179 return gsmtty_modem_update(dlci, encode);
3180}
3181
3182static void gsmtty_cleanup(struct tty_struct *tty)
3183{
3184 struct gsm_dlci *dlci = tty->driver_data;
3185 struct gsm_mux *gsm = dlci->gsm;
3186
3187 dlci_put(dlci);
3188 dlci_put(gsm->dlci[0]);
3189 mux_put(gsm);
3190}
3191
3192/* Virtual ttys for the demux */
3193static const struct tty_operations gsmtty_ops = {
3194 .install = gsmtty_install,
3195 .open = gsmtty_open,
3196 .close = gsmtty_close,
3197 .write = gsmtty_write,
3198 .write_room = gsmtty_write_room,
3199 .chars_in_buffer = gsmtty_chars_in_buffer,
3200 .flush_buffer = gsmtty_flush_buffer,
3201 .ioctl = gsmtty_ioctl,
3202 .throttle = gsmtty_throttle,
3203 .unthrottle = gsmtty_unthrottle,
3204 .set_termios = gsmtty_set_termios,
3205 .hangup = gsmtty_hangup,
3206 .wait_until_sent = gsmtty_wait_until_sent,
3207 .tiocmget = gsmtty_tiocmget,
3208 .tiocmset = gsmtty_tiocmset,
3209 .break_ctl = gsmtty_break_ctl,
3210 .cleanup = gsmtty_cleanup,
3211};
3212
3213
3214
3215static int __init gsm_init(void)
3216{
3217 /* Fill in our line protocol discipline, and register it */
3218 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3219 if (status != 0) {
3220 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3221 status);
3222 return status;
3223 }
3224
3225 gsm_tty_driver = alloc_tty_driver(256);
3226 if (!gsm_tty_driver) {
3227 tty_unregister_ldisc(N_GSM0710);
3228 pr_err("gsm_init: tty allocation failed.\n");
3229 return -EINVAL;
3230 }
3231 gsm_tty_driver->driver_name = "gsmtty";
3232 gsm_tty_driver->name = "gsmtty";
3233 gsm_tty_driver->major = 0; /* Dynamic */
3234 gsm_tty_driver->minor_start = 0;
3235 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3236 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3237 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3238 | TTY_DRIVER_HARDWARE_BREAK;
3239 gsm_tty_driver->init_termios = tty_std_termios;
3240 /* Fixme */
3241 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3242 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3243
3244 spin_lock_init(&gsm_mux_lock);
3245
3246 if (tty_register_driver(gsm_tty_driver)) {
3247 put_tty_driver(gsm_tty_driver);
3248 tty_unregister_ldisc(N_GSM0710);
3249 pr_err("gsm_init: tty registration failed.\n");
3250 return -EBUSY;
3251 }
3252 pr_debug("gsm_init: loaded as %d,%d.\n",
3253 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3254 return 0;
3255}
3256
3257static void __exit gsm_exit(void)
3258{
3259 int status = tty_unregister_ldisc(N_GSM0710);
3260 if (status != 0)
3261 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3262 status);
3263 tty_unregister_driver(gsm_tty_driver);
3264 put_tty_driver(gsm_tty_driver);
3265}
3266
3267module_init(gsm_init);
3268module_exit(gsm_exit);
3269
3270
3271MODULE_LICENSE("GPL");
3272MODULE_ALIAS_LDISC(N_GSM0710);