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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/*
2 * n_gsm.c GSM 0710 tty multiplexor
3 * Copyright (c) 2009/10 Intel Corporation
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 *
18 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
19 *
20 * TO DO:
21 * Mostly done: ioctls for setting modes/timing
22 * Partly done: hooks so you can pull off frames to non tty devs
23 * Restart DLCI 0 when it closes ?
24 * Improve the tx engine
25 * Resolve tx side locking by adding a queue_head and routing
26 * all control traffic via it
27 * General tidy/document
28 * Review the locking/move to refcounts more (mux now moved to an
29 * alloc/free model ready)
30 * Use newest tty open/close port helpers and install hooks
31 * What to do about power functions ?
32 * Termios setting and negotiation
33 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
34 *
35 */
36
37#include <linux/types.h>
38#include <linux/major.h>
39#include <linux/errno.h>
40#include <linux/signal.h>
41#include <linux/fcntl.h>
42#include <linux/sched.h>
43#include <linux/interrupt.h>
44#include <linux/tty.h>
45#include <linux/ctype.h>
46#include <linux/mm.h>
47#include <linux/string.h>
48#include <linux/slab.h>
49#include <linux/poll.h>
50#include <linux/bitops.h>
51#include <linux/file.h>
52#include <linux/uaccess.h>
53#include <linux/module.h>
54#include <linux/timer.h>
55#include <linux/tty_flip.h>
56#include <linux/tty_driver.h>
57#include <linux/serial.h>
58#include <linux/kfifo.h>
59#include <linux/skbuff.h>
60#include <net/arp.h>
61#include <linux/ip.h>
62#include <linux/netdevice.h>
63#include <linux/etherdevice.h>
64#include <linux/gsmmux.h>
65
66static int debug;
67module_param(debug, int, 0600);
68
69/* Defaults: these are from the specification */
70
71#define T1 10 /* 100mS */
72#define T2 34 /* 333mS */
73#define N2 3 /* Retry 3 times */
74
75/* Use long timers for testing at low speed with debug on */
76#ifdef DEBUG_TIMING
77#define T1 100
78#define T2 200
79#endif
80
81/*
82 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
83 * limits so this is plenty
84 */
85#define MAX_MRU 1500
86#define MAX_MTU 1500
87#define GSM_NET_TX_TIMEOUT (HZ*10)
88
89/**
90 * struct gsm_mux_net - network interface
91 * @struct gsm_dlci* dlci
92 * @struct net_device_stats stats;
93 *
94 * Created when net interface is initialized.
95 **/
96struct gsm_mux_net {
97 struct kref ref;
98 struct gsm_dlci *dlci;
99 struct net_device_stats stats;
100};
101
102#define STATS(net) (((struct gsm_mux_net *)netdev_priv(net))->stats)
103
104/*
105 * Each block of data we have queued to go out is in the form of
106 * a gsm_msg which holds everything we need in a link layer independent
107 * format
108 */
109
110struct gsm_msg {
111 struct list_head list;
112 u8 addr; /* DLCI address + flags */
113 u8 ctrl; /* Control byte + flags */
114 unsigned int len; /* Length of data block (can be zero) */
115 unsigned char *data; /* Points into buffer but not at the start */
116 unsigned char buffer[0];
117};
118
119/*
120 * Each active data link has a gsm_dlci structure associated which ties
121 * the link layer to an optional tty (if the tty side is open). To avoid
122 * complexity right now these are only ever freed up when the mux is
123 * shut down.
124 *
125 * At the moment we don't free DLCI objects until the mux is torn down
126 * this avoid object life time issues but might be worth review later.
127 */
128
129struct gsm_dlci {
130 struct gsm_mux *gsm;
131 int addr;
132 int state;
133#define DLCI_CLOSED 0
134#define DLCI_OPENING 1 /* Sending SABM not seen UA */
135#define DLCI_OPEN 2 /* SABM/UA complete */
136#define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
137 struct mutex mutex;
138
139 /* Link layer */
140 spinlock_t lock; /* Protects the internal state */
141 struct timer_list t1; /* Retransmit timer for SABM and UA */
142 int retries;
143 /* Uplink tty if active */
144 struct tty_port port; /* The tty bound to this DLCI if there is one */
145 struct kfifo *fifo; /* Queue fifo for the DLCI */
146 struct kfifo _fifo; /* For new fifo API porting only */
147 int adaption; /* Adaption layer in use */
148 int prev_adaption;
149 u32 modem_rx; /* Our incoming virtual modem lines */
150 u32 modem_tx; /* Our outgoing modem lines */
151 int dead; /* Refuse re-open */
152 /* Flow control */
153 int throttled; /* Private copy of throttle state */
154 int constipated; /* Throttle status for outgoing */
155 /* Packetised I/O */
156 struct sk_buff *skb; /* Frame being sent */
157 struct sk_buff_head skb_list; /* Queued frames */
158 /* Data handling callback */
159 void (*data)(struct gsm_dlci *dlci, u8 *data, int len);
160 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len);
161 struct net_device *net; /* network interface, if created */
162};
163
164/* DLCI 0, 62/63 are special or reserved see gsmtty_open */
165
166#define NUM_DLCI 64
167
168/*
169 * DLCI 0 is used to pass control blocks out of band of the data
170 * flow (and with a higher link priority). One command can be outstanding
171 * at a time and we use this structure to manage them. They are created
172 * and destroyed by the user context, and updated by the receive paths
173 * and timers
174 */
175
176struct gsm_control {
177 u8 cmd; /* Command we are issuing */
178 u8 *data; /* Data for the command in case we retransmit */
179 int len; /* Length of block for retransmission */
180 int done; /* Done flag */
181 int error; /* Error if any */
182};
183
184/*
185 * Each GSM mux we have is represented by this structure. If we are
186 * operating as an ldisc then we use this structure as our ldisc
187 * state. We need to sort out lifetimes and locking with respect
188 * to the gsm mux array. For now we don't free DLCI objects that
189 * have been instantiated until the mux itself is terminated.
190 *
191 * To consider further: tty open versus mux shutdown.
192 */
193
194struct gsm_mux {
195 struct tty_struct *tty; /* The tty our ldisc is bound to */
196 spinlock_t lock;
197 struct mutex mutex;
198 unsigned int num;
199 struct kref ref;
200
201 /* Events on the GSM channel */
202 wait_queue_head_t event;
203
204 /* Bits for GSM mode decoding */
205
206 /* Framing Layer */
207 unsigned char *buf;
208 int state;
209#define GSM_SEARCH 0
210#define GSM_START 1
211#define GSM_ADDRESS 2
212#define GSM_CONTROL 3
213#define GSM_LEN 4
214#define GSM_DATA 5
215#define GSM_FCS 6
216#define GSM_OVERRUN 7
217#define GSM_LEN0 8
218#define GSM_LEN1 9
219#define GSM_SSOF 10
220 unsigned int len;
221 unsigned int address;
222 unsigned int count;
223 int escape;
224 int encoding;
225 u8 control;
226 u8 fcs;
227 u8 received_fcs;
228 u8 *txframe; /* TX framing buffer */
229
230 /* Methods for the receiver side */
231 void (*receive)(struct gsm_mux *gsm, u8 ch);
232 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
233 /* And transmit side */
234 int (*output)(struct gsm_mux *mux, u8 *data, int len);
235
236 /* Link Layer */
237 unsigned int mru;
238 unsigned int mtu;
239 int initiator; /* Did we initiate connection */
240 int dead; /* Has the mux been shut down */
241 struct gsm_dlci *dlci[NUM_DLCI];
242 int constipated; /* Asked by remote to shut up */
243
244 spinlock_t tx_lock;
245 unsigned int tx_bytes; /* TX data outstanding */
246#define TX_THRESH_HI 8192
247#define TX_THRESH_LO 2048
248 struct list_head tx_list; /* Pending data packets */
249
250 /* Control messages */
251 struct timer_list t2_timer; /* Retransmit timer for commands */
252 int cretries; /* Command retry counter */
253 struct gsm_control *pending_cmd;/* Our current pending command */
254 spinlock_t control_lock; /* Protects the pending command */
255
256 /* Configuration */
257 int adaption; /* 1 or 2 supported */
258 u8 ftype; /* UI or UIH */
259 int t1, t2; /* Timers in 1/100th of a sec */
260 int n2; /* Retry count */
261
262 /* Statistics (not currently exposed) */
263 unsigned long bad_fcs;
264 unsigned long malformed;
265 unsigned long io_error;
266 unsigned long bad_size;
267 unsigned long unsupported;
268};
269
270
271/*
272 * Mux objects - needed so that we can translate a tty index into the
273 * relevant mux and DLCI.
274 */
275
276#define MAX_MUX 4 /* 256 minors */
277static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
278static spinlock_t gsm_mux_lock;
279
280static struct tty_driver *gsm_tty_driver;
281
282/*
283 * This section of the driver logic implements the GSM encodings
284 * both the basic and the 'advanced'. Reliable transport is not
285 * supported.
286 */
287
288#define CR 0x02
289#define EA 0x01
290#define PF 0x10
291
292/* I is special: the rest are ..*/
293#define RR 0x01
294#define UI 0x03
295#define RNR 0x05
296#define REJ 0x09
297#define DM 0x0F
298#define SABM 0x2F
299#define DISC 0x43
300#define UA 0x63
301#define UIH 0xEF
302
303/* Channel commands */
304#define CMD_NSC 0x09
305#define CMD_TEST 0x11
306#define CMD_PSC 0x21
307#define CMD_RLS 0x29
308#define CMD_FCOFF 0x31
309#define CMD_PN 0x41
310#define CMD_RPN 0x49
311#define CMD_FCON 0x51
312#define CMD_CLD 0x61
313#define CMD_SNC 0x69
314#define CMD_MSC 0x71
315
316/* Virtual modem bits */
317#define MDM_FC 0x01
318#define MDM_RTC 0x02
319#define MDM_RTR 0x04
320#define MDM_IC 0x20
321#define MDM_DV 0x40
322
323#define GSM0_SOF 0xF9
324#define GSM1_SOF 0x7E
325#define GSM1_ESCAPE 0x7D
326#define GSM1_ESCAPE_BITS 0x20
327#define XON 0x11
328#define XOFF 0x13
329
330static const struct tty_port_operations gsm_port_ops;
331
332/*
333 * CRC table for GSM 0710
334 */
335
336static const u8 gsm_fcs8[256] = {
337 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
338 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
339 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
340 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
341 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
342 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
343 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
344 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
345 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
346 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
347 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
348 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
349 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
350 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
351 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
352 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
353 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
354 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
355 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
356 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
357 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
358 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
359 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
360 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
361 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
362 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
363 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
364 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
365 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
366 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
367 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
368 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
369};
370
371#define INIT_FCS 0xFF
372#define GOOD_FCS 0xCF
373
374/**
375 * gsm_fcs_add - update FCS
376 * @fcs: Current FCS
377 * @c: Next data
378 *
379 * Update the FCS to include c. Uses the algorithm in the specification
380 * notes.
381 */
382
383static inline u8 gsm_fcs_add(u8 fcs, u8 c)
384{
385 return gsm_fcs8[fcs ^ c];
386}
387
388/**
389 * gsm_fcs_add_block - update FCS for a block
390 * @fcs: Current FCS
391 * @c: buffer of data
392 * @len: length of buffer
393 *
394 * Update the FCS to include c. Uses the algorithm in the specification
395 * notes.
396 */
397
398static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
399{
400 while (len--)
401 fcs = gsm_fcs8[fcs ^ *c++];
402 return fcs;
403}
404
405/**
406 * gsm_read_ea - read a byte into an EA
407 * @val: variable holding value
408 * c: byte going into the EA
409 *
410 * Processes one byte of an EA. Updates the passed variable
411 * and returns 1 if the EA is now completely read
412 */
413
414static int gsm_read_ea(unsigned int *val, u8 c)
415{
416 /* Add the next 7 bits into the value */
417 *val <<= 7;
418 *val |= c >> 1;
419 /* Was this the last byte of the EA 1 = yes*/
420 return c & EA;
421}
422
423/**
424 * gsm_encode_modem - encode modem data bits
425 * @dlci: DLCI to encode from
426 *
427 * Returns the correct GSM encoded modem status bits (6 bit field) for
428 * the current status of the DLCI and attached tty object
429 */
430
431static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
432{
433 u8 modembits = 0;
434 /* FC is true flow control not modem bits */
435 if (dlci->throttled)
436 modembits |= MDM_FC;
437 if (dlci->modem_tx & TIOCM_DTR)
438 modembits |= MDM_RTC;
439 if (dlci->modem_tx & TIOCM_RTS)
440 modembits |= MDM_RTR;
441 if (dlci->modem_tx & TIOCM_RI)
442 modembits |= MDM_IC;
443 if (dlci->modem_tx & TIOCM_CD)
444 modembits |= MDM_DV;
445 return modembits;
446}
447
448/**
449 * gsm_print_packet - display a frame for debug
450 * @hdr: header to print before decode
451 * @addr: address EA from the frame
452 * @cr: C/R bit from the frame
453 * @control: control including PF bit
454 * @data: following data bytes
455 * @dlen: length of data
456 *
457 * Displays a packet in human readable format for debugging purposes. The
458 * style is based on amateur radio LAP-B dump display.
459 */
460
461static void gsm_print_packet(const char *hdr, int addr, int cr,
462 u8 control, const u8 *data, int dlen)
463{
464 if (!(debug & 1))
465 return;
466
467 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
468
469 switch (control & ~PF) {
470 case SABM:
471 pr_cont("SABM");
472 break;
473 case UA:
474 pr_cont("UA");
475 break;
476 case DISC:
477 pr_cont("DISC");
478 break;
479 case DM:
480 pr_cont("DM");
481 break;
482 case UI:
483 pr_cont("UI");
484 break;
485 case UIH:
486 pr_cont("UIH");
487 break;
488 default:
489 if (!(control & 0x01)) {
490 pr_cont("I N(S)%d N(R)%d",
491 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
492 } else switch (control & 0x0F) {
493 case RR:
494 pr_cont("RR(%d)", (control & 0xE0) >> 5);
495 break;
496 case RNR:
497 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
498 break;
499 case REJ:
500 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
501 break;
502 default:
503 pr_cont("[%02X]", control);
504 }
505 }
506
507 if (control & PF)
508 pr_cont("(P)");
509 else
510 pr_cont("(F)");
511
512 if (dlen) {
513 int ct = 0;
514 while (dlen--) {
515 if (ct % 8 == 0) {
516 pr_cont("\n");
517 pr_debug(" ");
518 }
519 pr_cont("%02X ", *data++);
520 ct++;
521 }
522 }
523 pr_cont("\n");
524}
525
526
527/*
528 * Link level transmission side
529 */
530
531/**
532 * gsm_stuff_packet - bytestuff a packet
533 * @ibuf: input
534 * @obuf: output
535 * @len: length of input
536 *
537 * Expand a buffer by bytestuffing it. The worst case size change
538 * is doubling and the caller is responsible for handing out
539 * suitable sized buffers.
540 */
541
542static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
543{
544 int olen = 0;
545 while (len--) {
546 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
547 || *input == XON || *input == XOFF) {
548 *output++ = GSM1_ESCAPE;
549 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
550 olen++;
551 } else
552 *output++ = *input++;
553 olen++;
554 }
555 return olen;
556}
557
558/**
559 * gsm_send - send a control frame
560 * @gsm: our GSM mux
561 * @addr: address for control frame
562 * @cr: command/response bit
563 * @control: control byte including PF bit
564 *
565 * Format up and transmit a control frame. These do not go via the
566 * queueing logic as they should be transmitted ahead of data when
567 * they are needed.
568 *
569 * FIXME: Lock versus data TX path
570 */
571
572static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
573{
574 int len;
575 u8 cbuf[10];
576 u8 ibuf[3];
577
578 switch (gsm->encoding) {
579 case 0:
580 cbuf[0] = GSM0_SOF;
581 cbuf[1] = (addr << 2) | (cr << 1) | EA;
582 cbuf[2] = control;
583 cbuf[3] = EA; /* Length of data = 0 */
584 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
585 cbuf[5] = GSM0_SOF;
586 len = 6;
587 break;
588 case 1:
589 case 2:
590 /* Control frame + packing (but not frame stuffing) in mode 1 */
591 ibuf[0] = (addr << 2) | (cr << 1) | EA;
592 ibuf[1] = control;
593 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
594 /* Stuffing may double the size worst case */
595 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
596 /* Now add the SOF markers */
597 cbuf[0] = GSM1_SOF;
598 cbuf[len + 1] = GSM1_SOF;
599 /* FIXME: we can omit the lead one in many cases */
600 len += 2;
601 break;
602 default:
603 WARN_ON(1);
604 return;
605 }
606 gsm->output(gsm, cbuf, len);
607 gsm_print_packet("-->", addr, cr, control, NULL, 0);
608}
609
610/**
611 * gsm_response - send a control response
612 * @gsm: our GSM mux
613 * @addr: address for control frame
614 * @control: control byte including PF bit
615 *
616 * Format up and transmit a link level response frame.
617 */
618
619static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
620{
621 gsm_send(gsm, addr, 0, control);
622}
623
624/**
625 * gsm_command - send a control command
626 * @gsm: our GSM mux
627 * @addr: address for control frame
628 * @control: control byte including PF bit
629 *
630 * Format up and transmit a link level command frame.
631 */
632
633static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
634{
635 gsm_send(gsm, addr, 1, control);
636}
637
638/* Data transmission */
639
640#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
641
642/**
643 * gsm_data_alloc - allocate data frame
644 * @gsm: GSM mux
645 * @addr: DLCI address
646 * @len: length excluding header and FCS
647 * @ctrl: control byte
648 *
649 * Allocate a new data buffer for sending frames with data. Space is left
650 * at the front for header bytes but that is treated as an implementation
651 * detail and not for the high level code to use
652 */
653
654static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
655 u8 ctrl)
656{
657 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
658 GFP_ATOMIC);
659 if (m == NULL)
660 return NULL;
661 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
662 m->len = len;
663 m->addr = addr;
664 m->ctrl = ctrl;
665 INIT_LIST_HEAD(&m->list);
666 return m;
667}
668
669/**
670 * gsm_data_kick - poke the queue
671 * @gsm: GSM Mux
672 *
673 * The tty device has called us to indicate that room has appeared in
674 * the transmit queue. Ram more data into the pipe if we have any
675 * If we have been flow-stopped by a CMD_FCOFF, then we can only
676 * send messages on DLCI0 until CMD_FCON
677 *
678 * FIXME: lock against link layer control transmissions
679 */
680
681static void gsm_data_kick(struct gsm_mux *gsm)
682{
683 struct gsm_msg *msg, *nmsg;
684 int len;
685 int skip_sof = 0;
686
687 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
688 if (gsm->constipated && msg->addr)
689 continue;
690 if (gsm->encoding != 0) {
691 gsm->txframe[0] = GSM1_SOF;
692 len = gsm_stuff_frame(msg->data,
693 gsm->txframe + 1, msg->len);
694 gsm->txframe[len + 1] = GSM1_SOF;
695 len += 2;
696 } else {
697 gsm->txframe[0] = GSM0_SOF;
698 memcpy(gsm->txframe + 1 , msg->data, msg->len);
699 gsm->txframe[msg->len + 1] = GSM0_SOF;
700 len = msg->len + 2;
701 }
702
703 if (debug & 4)
704 print_hex_dump_bytes("gsm_data_kick: ",
705 DUMP_PREFIX_OFFSET,
706 gsm->txframe, len);
707
708 if (gsm->output(gsm, gsm->txframe + skip_sof,
709 len - skip_sof) < 0)
710 break;
711 /* FIXME: Can eliminate one SOF in many more cases */
712 gsm->tx_bytes -= msg->len;
713 /* For a burst of frames skip the extra SOF within the
714 burst */
715 skip_sof = 1;
716
717 list_del(&msg->list);
718 kfree(msg);
719 }
720}
721
722/**
723 * __gsm_data_queue - queue a UI or UIH frame
724 * @dlci: DLCI sending the data
725 * @msg: message queued
726 *
727 * Add data to the transmit queue and try and get stuff moving
728 * out of the mux tty if not already doing so. The Caller must hold
729 * the gsm tx lock.
730 */
731
732static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
733{
734 struct gsm_mux *gsm = dlci->gsm;
735 u8 *dp = msg->data;
736 u8 *fcs = dp + msg->len;
737
738 /* Fill in the header */
739 if (gsm->encoding == 0) {
740 if (msg->len < 128)
741 *--dp = (msg->len << 1) | EA;
742 else {
743 *--dp = (msg->len >> 7); /* bits 7 - 15 */
744 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
745 }
746 }
747
748 *--dp = msg->ctrl;
749 if (gsm->initiator)
750 *--dp = (msg->addr << 2) | 2 | EA;
751 else
752 *--dp = (msg->addr << 2) | EA;
753 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
754 /* Ugly protocol layering violation */
755 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
756 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
757 *fcs = 0xFF - *fcs;
758
759 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
760 msg->data, msg->len);
761
762 /* Move the header back and adjust the length, also allow for the FCS
763 now tacked on the end */
764 msg->len += (msg->data - dp) + 1;
765 msg->data = dp;
766
767 /* Add to the actual output queue */
768 list_add_tail(&msg->list, &gsm->tx_list);
769 gsm->tx_bytes += msg->len;
770 gsm_data_kick(gsm);
771}
772
773/**
774 * gsm_data_queue - queue a UI or UIH frame
775 * @dlci: DLCI sending the data
776 * @msg: message queued
777 *
778 * Add data to the transmit queue and try and get stuff moving
779 * out of the mux tty if not already doing so. Take the
780 * the gsm tx lock and dlci lock.
781 */
782
783static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
784{
785 unsigned long flags;
786 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
787 __gsm_data_queue(dlci, msg);
788 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
789}
790
791/**
792 * gsm_dlci_data_output - try and push data out of a DLCI
793 * @gsm: mux
794 * @dlci: the DLCI to pull data from
795 *
796 * Pull data from a DLCI and send it into the transmit queue if there
797 * is data. Keep to the MRU of the mux. This path handles the usual tty
798 * interface which is a byte stream with optional modem data.
799 *
800 * Caller must hold the tx_lock of the mux.
801 */
802
803static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
804{
805 struct gsm_msg *msg;
806 u8 *dp;
807 int len, total_size, size;
808 int h = dlci->adaption - 1;
809
810 total_size = 0;
811 while (1) {
812 len = kfifo_len(dlci->fifo);
813 if (len == 0)
814 return total_size;
815
816 /* MTU/MRU count only the data bits */
817 if (len > gsm->mtu)
818 len = gsm->mtu;
819
820 size = len + h;
821
822 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
823 /* FIXME: need a timer or something to kick this so it can't
824 get stuck with no work outstanding and no buffer free */
825 if (msg == NULL)
826 return -ENOMEM;
827 dp = msg->data;
828 switch (dlci->adaption) {
829 case 1: /* Unstructured */
830 break;
831 case 2: /* Unstructed with modem bits.
832 Always one byte as we never send inline break data */
833 *dp++ = gsm_encode_modem(dlci);
834 break;
835 }
836 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
837 __gsm_data_queue(dlci, msg);
838 total_size += size;
839 }
840 /* Bytes of data we used up */
841 return total_size;
842}
843
844/**
845 * gsm_dlci_data_output_framed - try and push data out of a DLCI
846 * @gsm: mux
847 * @dlci: the DLCI to pull data from
848 *
849 * Pull data from a DLCI and send it into the transmit queue if there
850 * is data. Keep to the MRU of the mux. This path handles framed data
851 * queued as skbuffs to the DLCI.
852 *
853 * Caller must hold the tx_lock of the mux.
854 */
855
856static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
857 struct gsm_dlci *dlci)
858{
859 struct gsm_msg *msg;
860 u8 *dp;
861 int len, size;
862 int last = 0, first = 0;
863 int overhead = 0;
864
865 /* One byte per frame is used for B/F flags */
866 if (dlci->adaption == 4)
867 overhead = 1;
868
869 /* dlci->skb is locked by tx_lock */
870 if (dlci->skb == NULL) {
871 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
872 if (dlci->skb == NULL)
873 return 0;
874 first = 1;
875 }
876 len = dlci->skb->len + overhead;
877
878 /* MTU/MRU count only the data bits */
879 if (len > gsm->mtu) {
880 if (dlci->adaption == 3) {
881 /* Over long frame, bin it */
882 dev_kfree_skb_any(dlci->skb);
883 dlci->skb = NULL;
884 return 0;
885 }
886 len = gsm->mtu;
887 } else
888 last = 1;
889
890 size = len + overhead;
891 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
892
893 /* FIXME: need a timer or something to kick this so it can't
894 get stuck with no work outstanding and no buffer free */
895 if (msg == NULL) {
896 skb_queue_tail(&dlci->skb_list, dlci->skb);
897 dlci->skb = NULL;
898 return -ENOMEM;
899 }
900 dp = msg->data;
901
902 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
903 /* Flag byte to carry the start/end info */
904 *dp++ = last << 7 | first << 6 | 1; /* EA */
905 len--;
906 }
907 memcpy(dp, dlci->skb->data, len);
908 skb_pull(dlci->skb, len);
909 __gsm_data_queue(dlci, msg);
910 if (last) {
911 dev_kfree_skb_any(dlci->skb);
912 dlci->skb = NULL;
913 }
914 return size;
915}
916
917/**
918 * gsm_dlci_data_sweep - look for data to send
919 * @gsm: the GSM mux
920 *
921 * Sweep the GSM mux channels in priority order looking for ones with
922 * data to send. We could do with optimising this scan a bit. We aim
923 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
924 * TX_THRESH_LO we get called again
925 *
926 * FIXME: We should round robin between groups and in theory you can
927 * renegotiate DLCI priorities with optional stuff. Needs optimising.
928 */
929
930static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
931{
932 int len;
933 /* Priority ordering: We should do priority with RR of the groups */
934 int i = 1;
935
936 while (i < NUM_DLCI) {
937 struct gsm_dlci *dlci;
938
939 if (gsm->tx_bytes > TX_THRESH_HI)
940 break;
941 dlci = gsm->dlci[i];
942 if (dlci == NULL || dlci->constipated) {
943 i++;
944 continue;
945 }
946 if (dlci->adaption < 3 && !dlci->net)
947 len = gsm_dlci_data_output(gsm, dlci);
948 else
949 len = gsm_dlci_data_output_framed(gsm, dlci);
950 if (len < 0)
951 break;
952 /* DLCI empty - try the next */
953 if (len == 0)
954 i++;
955 }
956}
957
958/**
959 * gsm_dlci_data_kick - transmit if possible
960 * @dlci: DLCI to kick
961 *
962 * Transmit data from this DLCI if the queue is empty. We can't rely on
963 * a tty wakeup except when we filled the pipe so we need to fire off
964 * new data ourselves in other cases.
965 */
966
967static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
968{
969 unsigned long flags;
970 int sweep;
971
972 if (dlci->constipated)
973 return;
974
975 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
976 /* If we have nothing running then we need to fire up */
977 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
978 if (dlci->gsm->tx_bytes == 0) {
979 if (dlci->net)
980 gsm_dlci_data_output_framed(dlci->gsm, dlci);
981 else
982 gsm_dlci_data_output(dlci->gsm, dlci);
983 }
984 if (sweep)
985 gsm_dlci_data_sweep(dlci->gsm);
986 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
987}
988
989/*
990 * Control message processing
991 */
992
993
994/**
995 * gsm_control_reply - send a response frame to a control
996 * @gsm: gsm channel
997 * @cmd: the command to use
998 * @data: data to follow encoded info
999 * @dlen: length of data
1000 *
1001 * Encode up and queue a UI/UIH frame containing our response.
1002 */
1003
1004static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data,
1005 int dlen)
1006{
1007 struct gsm_msg *msg;
1008 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
1009 if (msg == NULL)
1010 return;
1011 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1012 msg->data[1] = (dlen << 1) | EA;
1013 memcpy(msg->data + 2, data, dlen);
1014 gsm_data_queue(gsm->dlci[0], msg);
1015}
1016
1017/**
1018 * gsm_process_modem - process received modem status
1019 * @tty: virtual tty bound to the DLCI
1020 * @dlci: DLCI to affect
1021 * @modem: modem bits (full EA)
1022 *
1023 * Used when a modem control message or line state inline in adaption
1024 * layer 2 is processed. Sort out the local modem state and throttles
1025 */
1026
1027static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1028 u32 modem, int clen)
1029{
1030 int mlines = 0;
1031 u8 brk = 0;
1032 int fc;
1033
1034 /* The modem status command can either contain one octet (v.24 signals)
1035 or two octets (v.24 signals + break signals). The length field will
1036 either be 2 or 3 respectively. This is specified in section
1037 5.4.6.3.7 of the 27.010 mux spec. */
1038
1039 if (clen == 2)
1040 modem = modem & 0x7f;
1041 else {
1042 brk = modem & 0x7f;
1043 modem = (modem >> 7) & 0x7f;
1044 }
1045
1046 /* Flow control/ready to communicate */
1047 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1048 if (fc && !dlci->constipated) {
1049 /* Need to throttle our output on this device */
1050 dlci->constipated = 1;
1051 } else if (!fc && dlci->constipated) {
1052 dlci->constipated = 0;
1053 gsm_dlci_data_kick(dlci);
1054 }
1055
1056 /* Map modem bits */
1057 if (modem & MDM_RTC)
1058 mlines |= TIOCM_DSR | TIOCM_DTR;
1059 if (modem & MDM_RTR)
1060 mlines |= TIOCM_RTS | TIOCM_CTS;
1061 if (modem & MDM_IC)
1062 mlines |= TIOCM_RI;
1063 if (modem & MDM_DV)
1064 mlines |= TIOCM_CD;
1065
1066 /* Carrier drop -> hangup */
1067 if (tty) {
1068 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1069 if (!C_CLOCAL(tty))
1070 tty_hangup(tty);
1071 }
1072 if (brk & 0x01)
1073 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1074 dlci->modem_rx = mlines;
1075}
1076
1077/**
1078 * gsm_control_modem - modem status received
1079 * @gsm: GSM channel
1080 * @data: data following command
1081 * @clen: command length
1082 *
1083 * We have received a modem status control message. This is used by
1084 * the GSM mux protocol to pass virtual modem line status and optionally
1085 * to indicate break signals. Unpack it, convert to Linux representation
1086 * and if need be stuff a break message down the tty.
1087 */
1088
1089static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen)
1090{
1091 unsigned int addr = 0;
1092 unsigned int modem = 0;
1093 unsigned int brk = 0;
1094 struct gsm_dlci *dlci;
1095 int len = clen;
1096 u8 *dp = data;
1097 struct tty_struct *tty;
1098
1099 while (gsm_read_ea(&addr, *dp++) == 0) {
1100 len--;
1101 if (len == 0)
1102 return;
1103 }
1104 /* Must be at least one byte following the EA */
1105 len--;
1106 if (len <= 0)
1107 return;
1108
1109 addr >>= 1;
1110 /* Closed port, or invalid ? */
1111 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1112 return;
1113 dlci = gsm->dlci[addr];
1114
1115 while (gsm_read_ea(&modem, *dp++) == 0) {
1116 len--;
1117 if (len == 0)
1118 return;
1119 }
1120 len--;
1121 if (len > 0) {
1122 while (gsm_read_ea(&brk, *dp++) == 0) {
1123 len--;
1124 if (len == 0)
1125 return;
1126 }
1127 modem <<= 7;
1128 modem |= (brk & 0x7f);
1129 }
1130 tty = tty_port_tty_get(&dlci->port);
1131 gsm_process_modem(tty, dlci, modem, clen);
1132 if (tty) {
1133 tty_wakeup(tty);
1134 tty_kref_put(tty);
1135 }
1136 gsm_control_reply(gsm, CMD_MSC, data, clen);
1137}
1138
1139/**
1140 * gsm_control_rls - remote line status
1141 * @gsm: GSM channel
1142 * @data: data bytes
1143 * @clen: data length
1144 *
1145 * The modem sends us a two byte message on the control channel whenever
1146 * it wishes to send us an error state from the virtual link. Stuff
1147 * this into the uplink tty if present
1148 */
1149
1150static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen)
1151{
1152 struct tty_port *port;
1153 unsigned int addr = 0;
1154 u8 bits;
1155 int len = clen;
1156 u8 *dp = data;
1157
1158 while (gsm_read_ea(&addr, *dp++) == 0) {
1159 len--;
1160 if (len == 0)
1161 return;
1162 }
1163 /* Must be at least one byte following ea */
1164 len--;
1165 if (len <= 0)
1166 return;
1167 addr >>= 1;
1168 /* Closed port, or invalid ? */
1169 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1170 return;
1171 /* No error ? */
1172 bits = *dp;
1173 if ((bits & 1) == 0)
1174 return;
1175
1176 port = &gsm->dlci[addr]->port;
1177
1178 if (bits & 2)
1179 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1180 if (bits & 4)
1181 tty_insert_flip_char(port, 0, TTY_PARITY);
1182 if (bits & 8)
1183 tty_insert_flip_char(port, 0, TTY_FRAME);
1184
1185 tty_flip_buffer_push(port);
1186
1187 gsm_control_reply(gsm, CMD_RLS, data, clen);
1188}
1189
1190static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1191
1192/**
1193 * gsm_control_message - DLCI 0 control processing
1194 * @gsm: our GSM mux
1195 * @command: the command EA
1196 * @data: data beyond the command/length EAs
1197 * @clen: length
1198 *
1199 * Input processor for control messages from the other end of the link.
1200 * Processes the incoming request and queues a response frame or an
1201 * NSC response if not supported
1202 */
1203
1204static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1205 u8 *data, int clen)
1206{
1207 u8 buf[1];
1208 unsigned long flags;
1209
1210 switch (command) {
1211 case CMD_CLD: {
1212 struct gsm_dlci *dlci = gsm->dlci[0];
1213 /* Modem wishes to close down */
1214 if (dlci) {
1215 dlci->dead = 1;
1216 gsm->dead = 1;
1217 gsm_dlci_begin_close(dlci);
1218 }
1219 }
1220 break;
1221 case CMD_TEST:
1222 /* Modem wishes to test, reply with the data */
1223 gsm_control_reply(gsm, CMD_TEST, data, clen);
1224 break;
1225 case CMD_FCON:
1226 /* Modem can accept data again */
1227 gsm->constipated = 0;
1228 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1229 /* Kick the link in case it is idling */
1230 spin_lock_irqsave(&gsm->tx_lock, flags);
1231 gsm_data_kick(gsm);
1232 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1233 break;
1234 case CMD_FCOFF:
1235 /* Modem wants us to STFU */
1236 gsm->constipated = 1;
1237 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1238 break;
1239 case CMD_MSC:
1240 /* Out of band modem line change indicator for a DLCI */
1241 gsm_control_modem(gsm, data, clen);
1242 break;
1243 case CMD_RLS:
1244 /* Out of band error reception for a DLCI */
1245 gsm_control_rls(gsm, data, clen);
1246 break;
1247 case CMD_PSC:
1248 /* Modem wishes to enter power saving state */
1249 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1250 break;
1251 /* Optional unsupported commands */
1252 case CMD_PN: /* Parameter negotiation */
1253 case CMD_RPN: /* Remote port negotiation */
1254 case CMD_SNC: /* Service negotiation command */
1255 default:
1256 /* Reply to bad commands with an NSC */
1257 buf[0] = command;
1258 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1259 break;
1260 }
1261}
1262
1263/**
1264 * gsm_control_response - process a response to our control
1265 * @gsm: our GSM mux
1266 * @command: the command (response) EA
1267 * @data: data beyond the command/length EA
1268 * @clen: length
1269 *
1270 * Process a response to an outstanding command. We only allow a single
1271 * control message in flight so this is fairly easy. All the clean up
1272 * is done by the caller, we just update the fields, flag it as done
1273 * and return
1274 */
1275
1276static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1277 u8 *data, int clen)
1278{
1279 struct gsm_control *ctrl;
1280 unsigned long flags;
1281
1282 spin_lock_irqsave(&gsm->control_lock, flags);
1283
1284 ctrl = gsm->pending_cmd;
1285 /* Does the reply match our command */
1286 command |= 1;
1287 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1288 /* Our command was replied to, kill the retry timer */
1289 del_timer(&gsm->t2_timer);
1290 gsm->pending_cmd = NULL;
1291 /* Rejected by the other end */
1292 if (command == CMD_NSC)
1293 ctrl->error = -EOPNOTSUPP;
1294 ctrl->done = 1;
1295 wake_up(&gsm->event);
1296 }
1297 spin_unlock_irqrestore(&gsm->control_lock, flags);
1298}
1299
1300/**
1301 * gsm_control_transmit - send control packet
1302 * @gsm: gsm mux
1303 * @ctrl: frame to send
1304 *
1305 * Send out a pending control command (called under control lock)
1306 */
1307
1308static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1309{
1310 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1311 if (msg == NULL)
1312 return;
1313 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1314 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1315 gsm_data_queue(gsm->dlci[0], msg);
1316}
1317
1318/**
1319 * gsm_control_retransmit - retransmit a control frame
1320 * @data: pointer to our gsm object
1321 *
1322 * Called off the T2 timer expiry in order to retransmit control frames
1323 * that have been lost in the system somewhere. The control_lock protects
1324 * us from colliding with another sender or a receive completion event.
1325 * In that situation the timer may still occur in a small window but
1326 * gsm->pending_cmd will be NULL and we just let the timer expire.
1327 */
1328
1329static void gsm_control_retransmit(unsigned long data)
1330{
1331 struct gsm_mux *gsm = (struct gsm_mux *)data;
1332 struct gsm_control *ctrl;
1333 unsigned long flags;
1334 spin_lock_irqsave(&gsm->control_lock, flags);
1335 ctrl = gsm->pending_cmd;
1336 if (ctrl) {
1337 gsm->cretries--;
1338 if (gsm->cretries == 0) {
1339 gsm->pending_cmd = NULL;
1340 ctrl->error = -ETIMEDOUT;
1341 ctrl->done = 1;
1342 spin_unlock_irqrestore(&gsm->control_lock, flags);
1343 wake_up(&gsm->event);
1344 return;
1345 }
1346 gsm_control_transmit(gsm, ctrl);
1347 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1348 }
1349 spin_unlock_irqrestore(&gsm->control_lock, flags);
1350}
1351
1352/**
1353 * gsm_control_send - send a control frame on DLCI 0
1354 * @gsm: the GSM channel
1355 * @command: command to send including CR bit
1356 * @data: bytes of data (must be kmalloced)
1357 * @len: length of the block to send
1358 *
1359 * Queue and dispatch a control command. Only one command can be
1360 * active at a time. In theory more can be outstanding but the matching
1361 * gets really complicated so for now stick to one outstanding.
1362 */
1363
1364static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1365 unsigned int command, u8 *data, int clen)
1366{
1367 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1368 GFP_KERNEL);
1369 unsigned long flags;
1370 if (ctrl == NULL)
1371 return NULL;
1372retry:
1373 wait_event(gsm->event, gsm->pending_cmd == NULL);
1374 spin_lock_irqsave(&gsm->control_lock, flags);
1375 if (gsm->pending_cmd != NULL) {
1376 spin_unlock_irqrestore(&gsm->control_lock, flags);
1377 goto retry;
1378 }
1379 ctrl->cmd = command;
1380 ctrl->data = data;
1381 ctrl->len = clen;
1382 gsm->pending_cmd = ctrl;
1383 gsm->cretries = gsm->n2;
1384 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1385 gsm_control_transmit(gsm, ctrl);
1386 spin_unlock_irqrestore(&gsm->control_lock, flags);
1387 return ctrl;
1388}
1389
1390/**
1391 * gsm_control_wait - wait for a control to finish
1392 * @gsm: GSM mux
1393 * @control: control we are waiting on
1394 *
1395 * Waits for the control to complete or time out. Frees any used
1396 * resources and returns 0 for success, or an error if the remote
1397 * rejected or ignored the request.
1398 */
1399
1400static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1401{
1402 int err;
1403 wait_event(gsm->event, control->done == 1);
1404 err = control->error;
1405 kfree(control);
1406 return err;
1407}
1408
1409
1410/*
1411 * DLCI level handling: Needs krefs
1412 */
1413
1414/*
1415 * State transitions and timers
1416 */
1417
1418/**
1419 * gsm_dlci_close - a DLCI has closed
1420 * @dlci: DLCI that closed
1421 *
1422 * Perform processing when moving a DLCI into closed state. If there
1423 * is an attached tty this is hung up
1424 */
1425
1426static void gsm_dlci_close(struct gsm_dlci *dlci)
1427{
1428 del_timer(&dlci->t1);
1429 if (debug & 8)
1430 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1431 dlci->state = DLCI_CLOSED;
1432 if (dlci->addr != 0) {
1433 tty_port_tty_hangup(&dlci->port, false);
1434 kfifo_reset(dlci->fifo);
1435 } else
1436 dlci->gsm->dead = 1;
1437 wake_up(&dlci->gsm->event);
1438 /* A DLCI 0 close is a MUX termination so we need to kick that
1439 back to userspace somehow */
1440}
1441
1442/**
1443 * gsm_dlci_open - a DLCI has opened
1444 * @dlci: DLCI that opened
1445 *
1446 * Perform processing when moving a DLCI into open state.
1447 */
1448
1449static void gsm_dlci_open(struct gsm_dlci *dlci)
1450{
1451 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1452 open -> open */
1453 del_timer(&dlci->t1);
1454 /* This will let a tty open continue */
1455 dlci->state = DLCI_OPEN;
1456 if (debug & 8)
1457 pr_debug("DLCI %d goes open.\n", dlci->addr);
1458 wake_up(&dlci->gsm->event);
1459}
1460
1461/**
1462 * gsm_dlci_t1 - T1 timer expiry
1463 * @dlci: DLCI that opened
1464 *
1465 * The T1 timer handles retransmits of control frames (essentially of
1466 * SABM and DISC). We resend the command until the retry count runs out
1467 * in which case an opening port goes back to closed and a closing port
1468 * is simply put into closed state (any further frames from the other
1469 * end will get a DM response)
1470 */
1471
1472static void gsm_dlci_t1(unsigned long data)
1473{
1474 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1475 struct gsm_mux *gsm = dlci->gsm;
1476
1477 switch (dlci->state) {
1478 case DLCI_OPENING:
1479 dlci->retries--;
1480 if (dlci->retries) {
1481 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1482 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1483 } else
1484 gsm_dlci_close(dlci);
1485 break;
1486 case DLCI_CLOSING:
1487 dlci->retries--;
1488 if (dlci->retries) {
1489 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1490 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1491 } else
1492 gsm_dlci_close(dlci);
1493 break;
1494 }
1495}
1496
1497/**
1498 * gsm_dlci_begin_open - start channel open procedure
1499 * @dlci: DLCI to open
1500 *
1501 * Commence opening a DLCI from the Linux side. We issue SABM messages
1502 * to the modem which should then reply with a UA, at which point we
1503 * will move into open state. Opening is done asynchronously with retry
1504 * running off timers and the responses.
1505 */
1506
1507static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1508{
1509 struct gsm_mux *gsm = dlci->gsm;
1510 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1511 return;
1512 dlci->retries = gsm->n2;
1513 dlci->state = DLCI_OPENING;
1514 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1515 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1516}
1517
1518/**
1519 * gsm_dlci_begin_close - start channel open procedure
1520 * @dlci: DLCI to open
1521 *
1522 * Commence closing a DLCI from the Linux side. We issue DISC messages
1523 * to the modem which should then reply with a UA, at which point we
1524 * will move into closed state. Closing is done asynchronously with retry
1525 * off timers. We may also receive a DM reply from the other end which
1526 * indicates the channel was already closed.
1527 */
1528
1529static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1530{
1531 struct gsm_mux *gsm = dlci->gsm;
1532 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1533 return;
1534 dlci->retries = gsm->n2;
1535 dlci->state = DLCI_CLOSING;
1536 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1537 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1538}
1539
1540/**
1541 * gsm_dlci_data - data arrived
1542 * @dlci: channel
1543 * @data: block of bytes received
1544 * @len: length of received block
1545 *
1546 * A UI or UIH frame has arrived which contains data for a channel
1547 * other than the control channel. If the relevant virtual tty is
1548 * open we shovel the bits down it, if not we drop them.
1549 */
1550
1551static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen)
1552{
1553 /* krefs .. */
1554 struct tty_port *port = &dlci->port;
1555 struct tty_struct *tty;
1556 unsigned int modem = 0;
1557 int len = clen;
1558
1559 if (debug & 16)
1560 pr_debug("%d bytes for tty\n", len);
1561 switch (dlci->adaption) {
1562 /* Unsupported types */
1563 /* Packetised interruptible data */
1564 case 4:
1565 break;
1566 /* Packetised uininterruptible voice/data */
1567 case 3:
1568 break;
1569 /* Asynchronous serial with line state in each frame */
1570 case 2:
1571 while (gsm_read_ea(&modem, *data++) == 0) {
1572 len--;
1573 if (len == 0)
1574 return;
1575 }
1576 tty = tty_port_tty_get(port);
1577 if (tty) {
1578 gsm_process_modem(tty, dlci, modem, clen);
1579 tty_kref_put(tty);
1580 }
1581 /* Line state will go via DLCI 0 controls only */
1582 case 1:
1583 default:
1584 tty_insert_flip_string(port, data, len);
1585 tty_flip_buffer_push(port);
1586 }
1587}
1588
1589/**
1590 * gsm_dlci_control - data arrived on control channel
1591 * @dlci: channel
1592 * @data: block of bytes received
1593 * @len: length of received block
1594 *
1595 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1596 * control channel. This should contain a command EA followed by
1597 * control data bytes. The command EA contains a command/response bit
1598 * and we divide up the work accordingly.
1599 */
1600
1601static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1602{
1603 /* See what command is involved */
1604 unsigned int command = 0;
1605 while (len-- > 0) {
1606 if (gsm_read_ea(&command, *data++) == 1) {
1607 int clen = *data++;
1608 len--;
1609 /* FIXME: this is properly an EA */
1610 clen >>= 1;
1611 /* Malformed command ? */
1612 if (clen > len)
1613 return;
1614 if (command & 1)
1615 gsm_control_message(dlci->gsm, command,
1616 data, clen);
1617 else
1618 gsm_control_response(dlci->gsm, command,
1619 data, clen);
1620 return;
1621 }
1622 }
1623}
1624
1625/*
1626 * Allocate/Free DLCI channels
1627 */
1628
1629/**
1630 * gsm_dlci_alloc - allocate a DLCI
1631 * @gsm: GSM mux
1632 * @addr: address of the DLCI
1633 *
1634 * Allocate and install a new DLCI object into the GSM mux.
1635 *
1636 * FIXME: review locking races
1637 */
1638
1639static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1640{
1641 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1642 if (dlci == NULL)
1643 return NULL;
1644 spin_lock_init(&dlci->lock);
1645 mutex_init(&dlci->mutex);
1646 dlci->fifo = &dlci->_fifo;
1647 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1648 kfree(dlci);
1649 return NULL;
1650 }
1651
1652 skb_queue_head_init(&dlci->skb_list);
1653 init_timer(&dlci->t1);
1654 dlci->t1.function = gsm_dlci_t1;
1655 dlci->t1.data = (unsigned long)dlci;
1656 tty_port_init(&dlci->port);
1657 dlci->port.ops = &gsm_port_ops;
1658 dlci->gsm = gsm;
1659 dlci->addr = addr;
1660 dlci->adaption = gsm->adaption;
1661 dlci->state = DLCI_CLOSED;
1662 if (addr)
1663 dlci->data = gsm_dlci_data;
1664 else
1665 dlci->data = gsm_dlci_command;
1666 gsm->dlci[addr] = dlci;
1667 return dlci;
1668}
1669
1670/**
1671 * gsm_dlci_free - free DLCI
1672 * @dlci: DLCI to free
1673 *
1674 * Free up a DLCI.
1675 *
1676 * Can sleep.
1677 */
1678static void gsm_dlci_free(struct tty_port *port)
1679{
1680 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
1681
1682 del_timer_sync(&dlci->t1);
1683 dlci->gsm->dlci[dlci->addr] = NULL;
1684 kfifo_free(dlci->fifo);
1685 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1686 dev_kfree_skb(dlci->skb);
1687 kfree(dlci);
1688}
1689
1690static inline void dlci_get(struct gsm_dlci *dlci)
1691{
1692 tty_port_get(&dlci->port);
1693}
1694
1695static inline void dlci_put(struct gsm_dlci *dlci)
1696{
1697 tty_port_put(&dlci->port);
1698}
1699
1700static void gsm_destroy_network(struct gsm_dlci *dlci);
1701
1702/**
1703 * gsm_dlci_release - release DLCI
1704 * @dlci: DLCI to destroy
1705 *
1706 * Release a DLCI. Actual free is deferred until either
1707 * mux is closed or tty is closed - whichever is last.
1708 *
1709 * Can sleep.
1710 */
1711static void gsm_dlci_release(struct gsm_dlci *dlci)
1712{
1713 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1714 if (tty) {
1715 mutex_lock(&dlci->mutex);
1716 gsm_destroy_network(dlci);
1717 mutex_unlock(&dlci->mutex);
1718
1719 tty_vhangup(tty);
1720
1721 tty_port_tty_set(&dlci->port, NULL);
1722 tty_kref_put(tty);
1723 }
1724 dlci->state = DLCI_CLOSED;
1725 dlci_put(dlci);
1726}
1727
1728/*
1729 * LAPBish link layer logic
1730 */
1731
1732/**
1733 * gsm_queue - a GSM frame is ready to process
1734 * @gsm: pointer to our gsm mux
1735 *
1736 * At this point in time a frame has arrived and been demangled from
1737 * the line encoding. All the differences between the encodings have
1738 * been handled below us and the frame is unpacked into the structures.
1739 * The fcs holds the header FCS but any data FCS must be added here.
1740 */
1741
1742static void gsm_queue(struct gsm_mux *gsm)
1743{
1744 struct gsm_dlci *dlci;
1745 u8 cr;
1746 int address;
1747 /* We have to sneak a look at the packet body to do the FCS.
1748 A somewhat layering violation in the spec */
1749
1750 if ((gsm->control & ~PF) == UI)
1751 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1752 if (gsm->encoding == 0) {
1753 /* WARNING: gsm->received_fcs is used for
1754 gsm->encoding = 0 only.
1755 In this case it contain the last piece of data
1756 required to generate final CRC */
1757 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1758 }
1759 if (gsm->fcs != GOOD_FCS) {
1760 gsm->bad_fcs++;
1761 if (debug & 4)
1762 pr_debug("BAD FCS %02x\n", gsm->fcs);
1763 return;
1764 }
1765 address = gsm->address >> 1;
1766 if (address >= NUM_DLCI)
1767 goto invalid;
1768
1769 cr = gsm->address & 1; /* C/R bit */
1770
1771 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1772
1773 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1774 dlci = gsm->dlci[address];
1775
1776 switch (gsm->control) {
1777 case SABM|PF:
1778 if (cr == 0)
1779 goto invalid;
1780 if (dlci == NULL)
1781 dlci = gsm_dlci_alloc(gsm, address);
1782 if (dlci == NULL)
1783 return;
1784 if (dlci->dead)
1785 gsm_response(gsm, address, DM);
1786 else {
1787 gsm_response(gsm, address, UA);
1788 gsm_dlci_open(dlci);
1789 }
1790 break;
1791 case DISC|PF:
1792 if (cr == 0)
1793 goto invalid;
1794 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1795 gsm_response(gsm, address, DM);
1796 return;
1797 }
1798 /* Real close complete */
1799 gsm_response(gsm, address, UA);
1800 gsm_dlci_close(dlci);
1801 break;
1802 case UA:
1803 case UA|PF:
1804 if (cr == 0 || dlci == NULL)
1805 break;
1806 switch (dlci->state) {
1807 case DLCI_CLOSING:
1808 gsm_dlci_close(dlci);
1809 break;
1810 case DLCI_OPENING:
1811 gsm_dlci_open(dlci);
1812 break;
1813 }
1814 break;
1815 case DM: /* DM can be valid unsolicited */
1816 case DM|PF:
1817 if (cr)
1818 goto invalid;
1819 if (dlci == NULL)
1820 return;
1821 gsm_dlci_close(dlci);
1822 break;
1823 case UI:
1824 case UI|PF:
1825 case UIH:
1826 case UIH|PF:
1827#if 0
1828 if (cr)
1829 goto invalid;
1830#endif
1831 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1832 gsm_command(gsm, address, DM|PF);
1833 return;
1834 }
1835 dlci->data(dlci, gsm->buf, gsm->len);
1836 break;
1837 default:
1838 goto invalid;
1839 }
1840 return;
1841invalid:
1842 gsm->malformed++;
1843 return;
1844}
1845
1846
1847/**
1848 * gsm0_receive - perform processing for non-transparency
1849 * @gsm: gsm data for this ldisc instance
1850 * @c: character
1851 *
1852 * Receive bytes in gsm mode 0
1853 */
1854
1855static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1856{
1857 unsigned int len;
1858
1859 switch (gsm->state) {
1860 case GSM_SEARCH: /* SOF marker */
1861 if (c == GSM0_SOF) {
1862 gsm->state = GSM_ADDRESS;
1863 gsm->address = 0;
1864 gsm->len = 0;
1865 gsm->fcs = INIT_FCS;
1866 }
1867 break;
1868 case GSM_ADDRESS: /* Address EA */
1869 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1870 if (gsm_read_ea(&gsm->address, c))
1871 gsm->state = GSM_CONTROL;
1872 break;
1873 case GSM_CONTROL: /* Control Byte */
1874 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1875 gsm->control = c;
1876 gsm->state = GSM_LEN0;
1877 break;
1878 case GSM_LEN0: /* Length EA */
1879 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1880 if (gsm_read_ea(&gsm->len, c)) {
1881 if (gsm->len > gsm->mru) {
1882 gsm->bad_size++;
1883 gsm->state = GSM_SEARCH;
1884 break;
1885 }
1886 gsm->count = 0;
1887 if (!gsm->len)
1888 gsm->state = GSM_FCS;
1889 else
1890 gsm->state = GSM_DATA;
1891 break;
1892 }
1893 gsm->state = GSM_LEN1;
1894 break;
1895 case GSM_LEN1:
1896 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1897 len = c;
1898 gsm->len |= len << 7;
1899 if (gsm->len > gsm->mru) {
1900 gsm->bad_size++;
1901 gsm->state = GSM_SEARCH;
1902 break;
1903 }
1904 gsm->count = 0;
1905 if (!gsm->len)
1906 gsm->state = GSM_FCS;
1907 else
1908 gsm->state = GSM_DATA;
1909 break;
1910 case GSM_DATA: /* Data */
1911 gsm->buf[gsm->count++] = c;
1912 if (gsm->count == gsm->len)
1913 gsm->state = GSM_FCS;
1914 break;
1915 case GSM_FCS: /* FCS follows the packet */
1916 gsm->received_fcs = c;
1917 gsm_queue(gsm);
1918 gsm->state = GSM_SSOF;
1919 break;
1920 case GSM_SSOF:
1921 if (c == GSM0_SOF) {
1922 gsm->state = GSM_SEARCH;
1923 break;
1924 }
1925 break;
1926 }
1927}
1928
1929/**
1930 * gsm1_receive - perform processing for non-transparency
1931 * @gsm: gsm data for this ldisc instance
1932 * @c: character
1933 *
1934 * Receive bytes in mode 1 (Advanced option)
1935 */
1936
1937static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1938{
1939 if (c == GSM1_SOF) {
1940 /* EOF is only valid in frame if we have got to the data state
1941 and received at least one byte (the FCS) */
1942 if (gsm->state == GSM_DATA && gsm->count) {
1943 /* Extract the FCS */
1944 gsm->count--;
1945 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1946 gsm->len = gsm->count;
1947 gsm_queue(gsm);
1948 gsm->state = GSM_START;
1949 return;
1950 }
1951 /* Any partial frame was a runt so go back to start */
1952 if (gsm->state != GSM_START) {
1953 gsm->malformed++;
1954 gsm->state = GSM_START;
1955 }
1956 /* A SOF in GSM_START means we are still reading idling or
1957 framing bytes */
1958 return;
1959 }
1960
1961 if (c == GSM1_ESCAPE) {
1962 gsm->escape = 1;
1963 return;
1964 }
1965
1966 /* Only an unescaped SOF gets us out of GSM search */
1967 if (gsm->state == GSM_SEARCH)
1968 return;
1969
1970 if (gsm->escape) {
1971 c ^= GSM1_ESCAPE_BITS;
1972 gsm->escape = 0;
1973 }
1974 switch (gsm->state) {
1975 case GSM_START: /* First byte after SOF */
1976 gsm->address = 0;
1977 gsm->state = GSM_ADDRESS;
1978 gsm->fcs = INIT_FCS;
1979 /* Drop through */
1980 case GSM_ADDRESS: /* Address continuation */
1981 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1982 if (gsm_read_ea(&gsm->address, c))
1983 gsm->state = GSM_CONTROL;
1984 break;
1985 case GSM_CONTROL: /* Control Byte */
1986 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1987 gsm->control = c;
1988 gsm->count = 0;
1989 gsm->state = GSM_DATA;
1990 break;
1991 case GSM_DATA: /* Data */
1992 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
1993 gsm->state = GSM_OVERRUN;
1994 gsm->bad_size++;
1995 } else
1996 gsm->buf[gsm->count++] = c;
1997 break;
1998 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
1999 break;
2000 }
2001}
2002
2003/**
2004 * gsm_error - handle tty error
2005 * @gsm: ldisc data
2006 * @data: byte received (may be invalid)
2007 * @flag: error received
2008 *
2009 * Handle an error in the receipt of data for a frame. Currently we just
2010 * go back to hunting for a SOF.
2011 *
2012 * FIXME: better diagnostics ?
2013 */
2014
2015static void gsm_error(struct gsm_mux *gsm,
2016 unsigned char data, unsigned char flag)
2017{
2018 gsm->state = GSM_SEARCH;
2019 gsm->io_error++;
2020}
2021
2022/**
2023 * gsm_cleanup_mux - generic GSM protocol cleanup
2024 * @gsm: our mux
2025 *
2026 * Clean up the bits of the mux which are the same for all framing
2027 * protocols. Remove the mux from the mux table, stop all the timers
2028 * and then shut down each device hanging up the channels as we go.
2029 */
2030
2031static void gsm_cleanup_mux(struct gsm_mux *gsm)
2032{
2033 int i;
2034 struct gsm_dlci *dlci = gsm->dlci[0];
2035 struct gsm_msg *txq, *ntxq;
2036 struct gsm_control *gc;
2037
2038 gsm->dead = 1;
2039
2040 spin_lock(&gsm_mux_lock);
2041 for (i = 0; i < MAX_MUX; i++) {
2042 if (gsm_mux[i] == gsm) {
2043 gsm_mux[i] = NULL;
2044 break;
2045 }
2046 }
2047 spin_unlock(&gsm_mux_lock);
2048 WARN_ON(i == MAX_MUX);
2049
2050 /* In theory disconnecting DLCI 0 is sufficient but for some
2051 modems this is apparently not the case. */
2052 if (dlci) {
2053 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2054 if (gc)
2055 gsm_control_wait(gsm, gc);
2056 }
2057 del_timer_sync(&gsm->t2_timer);
2058 /* Now we are sure T2 has stopped */
2059 if (dlci) {
2060 dlci->dead = 1;
2061 gsm_dlci_begin_close(dlci);
2062 wait_event_interruptible(gsm->event,
2063 dlci->state == DLCI_CLOSED);
2064 }
2065 /* Free up any link layer users */
2066 mutex_lock(&gsm->mutex);
2067 for (i = 0; i < NUM_DLCI; i++)
2068 if (gsm->dlci[i])
2069 gsm_dlci_release(gsm->dlci[i]);
2070 mutex_unlock(&gsm->mutex);
2071 /* Now wipe the queues */
2072 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2073 kfree(txq);
2074 INIT_LIST_HEAD(&gsm->tx_list);
2075}
2076
2077/**
2078 * gsm_activate_mux - generic GSM setup
2079 * @gsm: our mux
2080 *
2081 * Set up the bits of the mux which are the same for all framing
2082 * protocols. Add the mux to the mux table so it can be opened and
2083 * finally kick off connecting to DLCI 0 on the modem.
2084 */
2085
2086static int gsm_activate_mux(struct gsm_mux *gsm)
2087{
2088 struct gsm_dlci *dlci;
2089 int i = 0;
2090
2091 setup_timer(&gsm->t2_timer, gsm_control_retransmit, (unsigned long)gsm);
2092 init_waitqueue_head(&gsm->event);
2093 spin_lock_init(&gsm->control_lock);
2094 spin_lock_init(&gsm->tx_lock);
2095
2096 if (gsm->encoding == 0)
2097 gsm->receive = gsm0_receive;
2098 else
2099 gsm->receive = gsm1_receive;
2100 gsm->error = gsm_error;
2101
2102 spin_lock(&gsm_mux_lock);
2103 for (i = 0; i < MAX_MUX; i++) {
2104 if (gsm_mux[i] == NULL) {
2105 gsm->num = i;
2106 gsm_mux[i] = gsm;
2107 break;
2108 }
2109 }
2110 spin_unlock(&gsm_mux_lock);
2111 if (i == MAX_MUX)
2112 return -EBUSY;
2113
2114 dlci = gsm_dlci_alloc(gsm, 0);
2115 if (dlci == NULL)
2116 return -ENOMEM;
2117 gsm->dead = 0; /* Tty opens are now permissible */
2118 return 0;
2119}
2120
2121/**
2122 * gsm_free_mux - free up a mux
2123 * @mux: mux to free
2124 *
2125 * Dispose of allocated resources for a dead mux
2126 */
2127static void gsm_free_mux(struct gsm_mux *gsm)
2128{
2129 kfree(gsm->txframe);
2130 kfree(gsm->buf);
2131 kfree(gsm);
2132}
2133
2134/**
2135 * gsm_free_muxr - free up a mux
2136 * @mux: mux to free
2137 *
2138 * Dispose of allocated resources for a dead mux
2139 */
2140static void gsm_free_muxr(struct kref *ref)
2141{
2142 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2143 gsm_free_mux(gsm);
2144}
2145
2146static inline void mux_get(struct gsm_mux *gsm)
2147{
2148 kref_get(&gsm->ref);
2149}
2150
2151static inline void mux_put(struct gsm_mux *gsm)
2152{
2153 kref_put(&gsm->ref, gsm_free_muxr);
2154}
2155
2156/**
2157 * gsm_alloc_mux - allocate a mux
2158 *
2159 * Creates a new mux ready for activation.
2160 */
2161
2162static struct gsm_mux *gsm_alloc_mux(void)
2163{
2164 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2165 if (gsm == NULL)
2166 return NULL;
2167 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2168 if (gsm->buf == NULL) {
2169 kfree(gsm);
2170 return NULL;
2171 }
2172 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2173 if (gsm->txframe == NULL) {
2174 kfree(gsm->buf);
2175 kfree(gsm);
2176 return NULL;
2177 }
2178 spin_lock_init(&gsm->lock);
2179 mutex_init(&gsm->mutex);
2180 kref_init(&gsm->ref);
2181 INIT_LIST_HEAD(&gsm->tx_list);
2182
2183 gsm->t1 = T1;
2184 gsm->t2 = T2;
2185 gsm->n2 = N2;
2186 gsm->ftype = UIH;
2187 gsm->adaption = 1;
2188 gsm->encoding = 1;
2189 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2190 gsm->mtu = 64;
2191 gsm->dead = 1; /* Avoid early tty opens */
2192
2193 return gsm;
2194}
2195
2196/**
2197 * gsmld_output - write to link
2198 * @gsm: our mux
2199 * @data: bytes to output
2200 * @len: size
2201 *
2202 * Write a block of data from the GSM mux to the data channel. This
2203 * will eventually be serialized from above but at the moment isn't.
2204 */
2205
2206static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2207{
2208 if (tty_write_room(gsm->tty) < len) {
2209 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2210 return -ENOSPC;
2211 }
2212 if (debug & 4)
2213 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2214 data, len);
2215 gsm->tty->ops->write(gsm->tty, data, len);
2216 return len;
2217}
2218
2219/**
2220 * gsmld_attach_gsm - mode set up
2221 * @tty: our tty structure
2222 * @gsm: our mux
2223 *
2224 * Set up the MUX for basic mode and commence connecting to the
2225 * modem. Currently called from the line discipline set up but
2226 * will need moving to an ioctl path.
2227 */
2228
2229static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2230{
2231 int ret, i, base;
2232
2233 gsm->tty = tty_kref_get(tty);
2234 gsm->output = gsmld_output;
2235 ret = gsm_activate_mux(gsm);
2236 if (ret != 0)
2237 tty_kref_put(gsm->tty);
2238 else {
2239 /* Don't register device 0 - this is the control channel and not
2240 a usable tty interface */
2241 base = gsm->num << 6; /* Base for this MUX */
2242 for (i = 1; i < NUM_DLCI; i++)
2243 tty_register_device(gsm_tty_driver, base + i, NULL);
2244 }
2245 return ret;
2246}
2247
2248
2249/**
2250 * gsmld_detach_gsm - stop doing 0710 mux
2251 * @tty: tty attached to the mux
2252 * @gsm: mux
2253 *
2254 * Shutdown and then clean up the resources used by the line discipline
2255 */
2256
2257static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2258{
2259 int i;
2260 int base = gsm->num << 6; /* Base for this MUX */
2261
2262 WARN_ON(tty != gsm->tty);
2263 for (i = 1; i < NUM_DLCI; i++)
2264 tty_unregister_device(gsm_tty_driver, base + i);
2265 gsm_cleanup_mux(gsm);
2266 tty_kref_put(gsm->tty);
2267 gsm->tty = NULL;
2268}
2269
2270static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2271 char *fp, int count)
2272{
2273 struct gsm_mux *gsm = tty->disc_data;
2274 const unsigned char *dp;
2275 char *f;
2276 int i;
2277 char flags = TTY_NORMAL;
2278
2279 if (debug & 4)
2280 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2281 cp, count);
2282
2283 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2284 if (f)
2285 flags = *f++;
2286 switch (flags) {
2287 case TTY_NORMAL:
2288 gsm->receive(gsm, *dp);
2289 break;
2290 case TTY_OVERRUN:
2291 case TTY_BREAK:
2292 case TTY_PARITY:
2293 case TTY_FRAME:
2294 gsm->error(gsm, *dp, flags);
2295 break;
2296 default:
2297 WARN_ONCE(1, "%s: unknown flag %d\n",
2298 tty_name(tty), flags);
2299 break;
2300 }
2301 }
2302 /* FASYNC if needed ? */
2303 /* If clogged call tty_throttle(tty); */
2304}
2305
2306/**
2307 * gsmld_flush_buffer - clean input queue
2308 * @tty: terminal device
2309 *
2310 * Flush the input buffer. Called when the line discipline is
2311 * being closed, when the tty layer wants the buffer flushed (eg
2312 * at hangup).
2313 */
2314
2315static void gsmld_flush_buffer(struct tty_struct *tty)
2316{
2317}
2318
2319/**
2320 * gsmld_close - close the ldisc for this tty
2321 * @tty: device
2322 *
2323 * Called from the terminal layer when this line discipline is
2324 * being shut down, either because of a close or becsuse of a
2325 * discipline change. The function will not be called while other
2326 * ldisc methods are in progress.
2327 */
2328
2329static void gsmld_close(struct tty_struct *tty)
2330{
2331 struct gsm_mux *gsm = tty->disc_data;
2332
2333 gsmld_detach_gsm(tty, gsm);
2334
2335 gsmld_flush_buffer(tty);
2336 /* Do other clean up here */
2337 mux_put(gsm);
2338}
2339
2340/**
2341 * gsmld_open - open an ldisc
2342 * @tty: terminal to open
2343 *
2344 * Called when this line discipline is being attached to the
2345 * terminal device. Can sleep. Called serialized so that no
2346 * other events will occur in parallel. No further open will occur
2347 * until a close.
2348 */
2349
2350static int gsmld_open(struct tty_struct *tty)
2351{
2352 struct gsm_mux *gsm;
2353 int ret;
2354
2355 if (tty->ops->write == NULL)
2356 return -EINVAL;
2357
2358 /* Attach our ldisc data */
2359 gsm = gsm_alloc_mux();
2360 if (gsm == NULL)
2361 return -ENOMEM;
2362
2363 tty->disc_data = gsm;
2364 tty->receive_room = 65536;
2365
2366 /* Attach the initial passive connection */
2367 gsm->encoding = 1;
2368
2369 ret = gsmld_attach_gsm(tty, gsm);
2370 if (ret != 0) {
2371 gsm_cleanup_mux(gsm);
2372 mux_put(gsm);
2373 }
2374 return ret;
2375}
2376
2377/**
2378 * gsmld_write_wakeup - asynchronous I/O notifier
2379 * @tty: tty device
2380 *
2381 * Required for the ptys, serial driver etc. since processes
2382 * that attach themselves to the master and rely on ASYNC
2383 * IO must be woken up
2384 */
2385
2386static void gsmld_write_wakeup(struct tty_struct *tty)
2387{
2388 struct gsm_mux *gsm = tty->disc_data;
2389 unsigned long flags;
2390
2391 /* Queue poll */
2392 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2393 spin_lock_irqsave(&gsm->tx_lock, flags);
2394 gsm_data_kick(gsm);
2395 if (gsm->tx_bytes < TX_THRESH_LO) {
2396 gsm_dlci_data_sweep(gsm);
2397 }
2398 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2399}
2400
2401/**
2402 * gsmld_read - read function for tty
2403 * @tty: tty device
2404 * @file: file object
2405 * @buf: userspace buffer pointer
2406 * @nr: size of I/O
2407 *
2408 * Perform reads for the line discipline. We are guaranteed that the
2409 * line discipline will not be closed under us but we may get multiple
2410 * parallel readers and must handle this ourselves. We may also get
2411 * a hangup. Always called in user context, may sleep.
2412 *
2413 * This code must be sure never to sleep through a hangup.
2414 */
2415
2416static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2417 unsigned char __user *buf, size_t nr)
2418{
2419 return -EOPNOTSUPP;
2420}
2421
2422/**
2423 * gsmld_write - write function for tty
2424 * @tty: tty device
2425 * @file: file object
2426 * @buf: userspace buffer pointer
2427 * @nr: size of I/O
2428 *
2429 * Called when the owner of the device wants to send a frame
2430 * itself (or some other control data). The data is transferred
2431 * as-is and must be properly framed and checksummed as appropriate
2432 * by userspace. Frames are either sent whole or not at all as this
2433 * avoids pain user side.
2434 */
2435
2436static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2437 const unsigned char *buf, size_t nr)
2438{
2439 int space = tty_write_room(tty);
2440 if (space >= nr)
2441 return tty->ops->write(tty, buf, nr);
2442 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2443 return -ENOBUFS;
2444}
2445
2446/**
2447 * gsmld_poll - poll method for N_GSM0710
2448 * @tty: terminal device
2449 * @file: file accessing it
2450 * @wait: poll table
2451 *
2452 * Called when the line discipline is asked to poll() for data or
2453 * for special events. This code is not serialized with respect to
2454 * other events save open/close.
2455 *
2456 * This code must be sure never to sleep through a hangup.
2457 * Called without the kernel lock held - fine
2458 */
2459
2460static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2461 poll_table *wait)
2462{
2463 unsigned int mask = 0;
2464 struct gsm_mux *gsm = tty->disc_data;
2465
2466 poll_wait(file, &tty->read_wait, wait);
2467 poll_wait(file, &tty->write_wait, wait);
2468 if (tty_hung_up_p(file))
2469 mask |= POLLHUP;
2470 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2471 mask |= POLLOUT | POLLWRNORM;
2472 if (gsm->dead)
2473 mask |= POLLHUP;
2474 return mask;
2475}
2476
2477static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2478 struct gsm_config *c)
2479{
2480 int need_close = 0;
2481 int need_restart = 0;
2482
2483 /* Stuff we don't support yet - UI or I frame transport, windowing */
2484 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2485 return -EOPNOTSUPP;
2486 /* Check the MRU/MTU range looks sane */
2487 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2488 return -EINVAL;
2489 if (c->n2 < 3)
2490 return -EINVAL;
2491 if (c->encapsulation > 1) /* Basic, advanced, no I */
2492 return -EINVAL;
2493 if (c->initiator > 1)
2494 return -EINVAL;
2495 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2496 return -EINVAL;
2497 /*
2498 * See what is needed for reconfiguration
2499 */
2500
2501 /* Timing fields */
2502 if (c->t1 != 0 && c->t1 != gsm->t1)
2503 need_restart = 1;
2504 if (c->t2 != 0 && c->t2 != gsm->t2)
2505 need_restart = 1;
2506 if (c->encapsulation != gsm->encoding)
2507 need_restart = 1;
2508 if (c->adaption != gsm->adaption)
2509 need_restart = 1;
2510 /* Requires care */
2511 if (c->initiator != gsm->initiator)
2512 need_close = 1;
2513 if (c->mru != gsm->mru)
2514 need_restart = 1;
2515 if (c->mtu != gsm->mtu)
2516 need_restart = 1;
2517
2518 /*
2519 * Close down what is needed, restart and initiate the new
2520 * configuration
2521 */
2522
2523 if (need_close || need_restart) {
2524 gsm_dlci_begin_close(gsm->dlci[0]);
2525 /* This will timeout if the link is down due to N2 expiring */
2526 wait_event_interruptible(gsm->event,
2527 gsm->dlci[0]->state == DLCI_CLOSED);
2528 if (signal_pending(current))
2529 return -EINTR;
2530 }
2531 if (need_restart)
2532 gsm_cleanup_mux(gsm);
2533
2534 gsm->initiator = c->initiator;
2535 gsm->mru = c->mru;
2536 gsm->mtu = c->mtu;
2537 gsm->encoding = c->encapsulation;
2538 gsm->adaption = c->adaption;
2539 gsm->n2 = c->n2;
2540
2541 if (c->i == 1)
2542 gsm->ftype = UIH;
2543 else if (c->i == 2)
2544 gsm->ftype = UI;
2545
2546 if (c->t1)
2547 gsm->t1 = c->t1;
2548 if (c->t2)
2549 gsm->t2 = c->t2;
2550
2551 /* FIXME: We need to separate activation/deactivation from adding
2552 and removing from the mux array */
2553 if (need_restart)
2554 gsm_activate_mux(gsm);
2555 if (gsm->initiator && need_close)
2556 gsm_dlci_begin_open(gsm->dlci[0]);
2557 return 0;
2558}
2559
2560static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2561 unsigned int cmd, unsigned long arg)
2562{
2563 struct gsm_config c;
2564 struct gsm_mux *gsm = tty->disc_data;
2565
2566 switch (cmd) {
2567 case GSMIOC_GETCONF:
2568 memset(&c, 0, sizeof(c));
2569 c.adaption = gsm->adaption;
2570 c.encapsulation = gsm->encoding;
2571 c.initiator = gsm->initiator;
2572 c.t1 = gsm->t1;
2573 c.t2 = gsm->t2;
2574 c.t3 = 0; /* Not supported */
2575 c.n2 = gsm->n2;
2576 if (gsm->ftype == UIH)
2577 c.i = 1;
2578 else
2579 c.i = 2;
2580 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
2581 c.mru = gsm->mru;
2582 c.mtu = gsm->mtu;
2583 c.k = 0;
2584 if (copy_to_user((void *)arg, &c, sizeof(c)))
2585 return -EFAULT;
2586 return 0;
2587 case GSMIOC_SETCONF:
2588 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2589 return -EFAULT;
2590 return gsmld_config(tty, gsm, &c);
2591 default:
2592 return n_tty_ioctl_helper(tty, file, cmd, arg);
2593 }
2594}
2595
2596/*
2597 * Network interface
2598 *
2599 */
2600
2601static int gsm_mux_net_open(struct net_device *net)
2602{
2603 pr_debug("%s called\n", __func__);
2604 netif_start_queue(net);
2605 return 0;
2606}
2607
2608static int gsm_mux_net_close(struct net_device *net)
2609{
2610 netif_stop_queue(net);
2611 return 0;
2612}
2613
2614static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net)
2615{
2616 return &((struct gsm_mux_net *)netdev_priv(net))->stats;
2617}
2618static void dlci_net_free(struct gsm_dlci *dlci)
2619{
2620 if (!dlci->net) {
2621 WARN_ON(1);
2622 return;
2623 }
2624 dlci->adaption = dlci->prev_adaption;
2625 dlci->data = dlci->prev_data;
2626 free_netdev(dlci->net);
2627 dlci->net = NULL;
2628}
2629static void net_free(struct kref *ref)
2630{
2631 struct gsm_mux_net *mux_net;
2632 struct gsm_dlci *dlci;
2633
2634 mux_net = container_of(ref, struct gsm_mux_net, ref);
2635 dlci = mux_net->dlci;
2636
2637 if (dlci->net) {
2638 unregister_netdev(dlci->net);
2639 dlci_net_free(dlci);
2640 }
2641}
2642
2643static inline void muxnet_get(struct gsm_mux_net *mux_net)
2644{
2645 kref_get(&mux_net->ref);
2646}
2647
2648static inline void muxnet_put(struct gsm_mux_net *mux_net)
2649{
2650 kref_put(&mux_net->ref, net_free);
2651}
2652
2653static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2654 struct net_device *net)
2655{
2656 struct gsm_mux_net *mux_net = netdev_priv(net);
2657 struct gsm_dlci *dlci = mux_net->dlci;
2658 muxnet_get(mux_net);
2659
2660 skb_queue_head(&dlci->skb_list, skb);
2661 STATS(net).tx_packets++;
2662 STATS(net).tx_bytes += skb->len;
2663 gsm_dlci_data_kick(dlci);
2664 /* And tell the kernel when the last transmit started. */
2665 net->trans_start = jiffies;
2666 muxnet_put(mux_net);
2667 return NETDEV_TX_OK;
2668}
2669
2670/* called when a packet did not ack after watchdogtimeout */
2671static void gsm_mux_net_tx_timeout(struct net_device *net)
2672{
2673 /* Tell syslog we are hosed. */
2674 dev_dbg(&net->dev, "Tx timed out.\n");
2675
2676 /* Update statistics */
2677 STATS(net).tx_errors++;
2678}
2679
2680static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2681 unsigned char *in_buf, int size)
2682{
2683 struct net_device *net = dlci->net;
2684 struct sk_buff *skb;
2685 struct gsm_mux_net *mux_net = netdev_priv(net);
2686 muxnet_get(mux_net);
2687
2688 /* Allocate an sk_buff */
2689 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2690 if (!skb) {
2691 /* We got no receive buffer. */
2692 STATS(net).rx_dropped++;
2693 muxnet_put(mux_net);
2694 return;
2695 }
2696 skb_reserve(skb, NET_IP_ALIGN);
2697 memcpy(skb_put(skb, size), in_buf, size);
2698
2699 skb->dev = net;
2700 skb->protocol = htons(ETH_P_IP);
2701
2702 /* Ship it off to the kernel */
2703 netif_rx(skb);
2704
2705 /* update out statistics */
2706 STATS(net).rx_packets++;
2707 STATS(net).rx_bytes += size;
2708 muxnet_put(mux_net);
2709 return;
2710}
2711
2712static int gsm_change_mtu(struct net_device *net, int new_mtu)
2713{
2714 struct gsm_mux_net *mux_net = netdev_priv(net);
2715 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu))
2716 return -EINVAL;
2717 net->mtu = new_mtu;
2718 return 0;
2719}
2720
2721static void gsm_mux_net_init(struct net_device *net)
2722{
2723 static const struct net_device_ops gsm_netdev_ops = {
2724 .ndo_open = gsm_mux_net_open,
2725 .ndo_stop = gsm_mux_net_close,
2726 .ndo_start_xmit = gsm_mux_net_start_xmit,
2727 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2728 .ndo_get_stats = gsm_mux_net_get_stats,
2729 .ndo_change_mtu = gsm_change_mtu,
2730 };
2731
2732 net->netdev_ops = &gsm_netdev_ops;
2733
2734 /* fill in the other fields */
2735 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2736 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2737 net->type = ARPHRD_NONE;
2738 net->tx_queue_len = 10;
2739}
2740
2741
2742/* caller holds the dlci mutex */
2743static void gsm_destroy_network(struct gsm_dlci *dlci)
2744{
2745 struct gsm_mux_net *mux_net;
2746
2747 pr_debug("destroy network interface");
2748 if (!dlci->net)
2749 return;
2750 mux_net = netdev_priv(dlci->net);
2751 muxnet_put(mux_net);
2752}
2753
2754
2755/* caller holds the dlci mutex */
2756static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2757{
2758 char *netname;
2759 int retval = 0;
2760 struct net_device *net;
2761 struct gsm_mux_net *mux_net;
2762
2763 if (!capable(CAP_NET_ADMIN))
2764 return -EPERM;
2765
2766 /* Already in a non tty mode */
2767 if (dlci->adaption > 2)
2768 return -EBUSY;
2769
2770 if (nc->protocol != htons(ETH_P_IP))
2771 return -EPROTONOSUPPORT;
2772
2773 if (nc->adaption != 3 && nc->adaption != 4)
2774 return -EPROTONOSUPPORT;
2775
2776 pr_debug("create network interface");
2777
2778 netname = "gsm%d";
2779 if (nc->if_name[0] != '\0')
2780 netname = nc->if_name;
2781 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
2782 NET_NAME_UNKNOWN, gsm_mux_net_init);
2783 if (!net) {
2784 pr_err("alloc_netdev failed");
2785 return -ENOMEM;
2786 }
2787 net->mtu = dlci->gsm->mtu;
2788 mux_net = netdev_priv(net);
2789 mux_net->dlci = dlci;
2790 kref_init(&mux_net->ref);
2791 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2792
2793 /* reconfigure dlci for network */
2794 dlci->prev_adaption = dlci->adaption;
2795 dlci->prev_data = dlci->data;
2796 dlci->adaption = nc->adaption;
2797 dlci->data = gsm_mux_rx_netchar;
2798 dlci->net = net;
2799
2800 pr_debug("register netdev");
2801 retval = register_netdev(net);
2802 if (retval) {
2803 pr_err("network register fail %d\n", retval);
2804 dlci_net_free(dlci);
2805 return retval;
2806 }
2807 return net->ifindex; /* return network index */
2808}
2809
2810/* Line discipline for real tty */
2811static struct tty_ldisc_ops tty_ldisc_packet = {
2812 .owner = THIS_MODULE,
2813 .magic = TTY_LDISC_MAGIC,
2814 .name = "n_gsm",
2815 .open = gsmld_open,
2816 .close = gsmld_close,
2817 .flush_buffer = gsmld_flush_buffer,
2818 .read = gsmld_read,
2819 .write = gsmld_write,
2820 .ioctl = gsmld_ioctl,
2821 .poll = gsmld_poll,
2822 .receive_buf = gsmld_receive_buf,
2823 .write_wakeup = gsmld_write_wakeup
2824};
2825
2826/*
2827 * Virtual tty side
2828 */
2829
2830#define TX_SIZE 512
2831
2832static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2833{
2834 u8 modembits[5];
2835 struct gsm_control *ctrl;
2836 int len = 2;
2837
2838 if (brk)
2839 len++;
2840
2841 modembits[0] = len << 1 | EA; /* Data bytes */
2842 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2843 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2844 if (brk)
2845 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2846 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2847 if (ctrl == NULL)
2848 return -ENOMEM;
2849 return gsm_control_wait(dlci->gsm, ctrl);
2850}
2851
2852static int gsm_carrier_raised(struct tty_port *port)
2853{
2854 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2855 /* Not yet open so no carrier info */
2856 if (dlci->state != DLCI_OPEN)
2857 return 0;
2858 if (debug & 2)
2859 return 1;
2860 return dlci->modem_rx & TIOCM_CD;
2861}
2862
2863static void gsm_dtr_rts(struct tty_port *port, int onoff)
2864{
2865 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2866 unsigned int modem_tx = dlci->modem_tx;
2867 if (onoff)
2868 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2869 else
2870 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2871 if (modem_tx != dlci->modem_tx) {
2872 dlci->modem_tx = modem_tx;
2873 gsmtty_modem_update(dlci, 0);
2874 }
2875}
2876
2877static const struct tty_port_operations gsm_port_ops = {
2878 .carrier_raised = gsm_carrier_raised,
2879 .dtr_rts = gsm_dtr_rts,
2880 .destruct = gsm_dlci_free,
2881};
2882
2883static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
2884{
2885 struct gsm_mux *gsm;
2886 struct gsm_dlci *dlci;
2887 unsigned int line = tty->index;
2888 unsigned int mux = line >> 6;
2889 bool alloc = false;
2890 int ret;
2891
2892 line = line & 0x3F;
2893
2894 if (mux >= MAX_MUX)
2895 return -ENXIO;
2896 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2897 if (gsm_mux[mux] == NULL)
2898 return -EUNATCH;
2899 if (line == 0 || line > 61) /* 62/63 reserved */
2900 return -ECHRNG;
2901 gsm = gsm_mux[mux];
2902 if (gsm->dead)
2903 return -EL2HLT;
2904 /* If DLCI 0 is not yet fully open return an error.
2905 This is ok from a locking
2906 perspective as we don't have to worry about this
2907 if DLCI0 is lost */
2908 mutex_lock(&gsm->mutex);
2909 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
2910 mutex_unlock(&gsm->mutex);
2911 return -EL2NSYNC;
2912 }
2913 dlci = gsm->dlci[line];
2914 if (dlci == NULL) {
2915 alloc = true;
2916 dlci = gsm_dlci_alloc(gsm, line);
2917 }
2918 if (dlci == NULL) {
2919 mutex_unlock(&gsm->mutex);
2920 return -ENOMEM;
2921 }
2922 ret = tty_port_install(&dlci->port, driver, tty);
2923 if (ret) {
2924 if (alloc)
2925 dlci_put(dlci);
2926 mutex_unlock(&gsm->mutex);
2927 return ret;
2928 }
2929
2930 dlci_get(dlci);
2931 dlci_get(gsm->dlci[0]);
2932 mux_get(gsm);
2933 tty->driver_data = dlci;
2934 mutex_unlock(&gsm->mutex);
2935
2936 return 0;
2937}
2938
2939static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2940{
2941 struct gsm_dlci *dlci = tty->driver_data;
2942 struct tty_port *port = &dlci->port;
2943
2944 port->count++;
2945 tty_port_tty_set(port, tty);
2946
2947 dlci->modem_rx = 0;
2948 /* We could in theory open and close before we wait - eg if we get
2949 a DM straight back. This is ok as that will have caused a hangup */
2950 set_bit(ASYNCB_INITIALIZED, &port->flags);
2951 /* Start sending off SABM messages */
2952 gsm_dlci_begin_open(dlci);
2953 /* And wait for virtual carrier */
2954 return tty_port_block_til_ready(port, tty, filp);
2955}
2956
2957static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2958{
2959 struct gsm_dlci *dlci = tty->driver_data;
2960 struct gsm_mux *gsm;
2961
2962 if (dlci == NULL)
2963 return;
2964 if (dlci->state == DLCI_CLOSED)
2965 return;
2966 mutex_lock(&dlci->mutex);
2967 gsm_destroy_network(dlci);
2968 mutex_unlock(&dlci->mutex);
2969 gsm = dlci->gsm;
2970 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
2971 return;
2972 gsm_dlci_begin_close(dlci);
2973 if (test_bit(ASYNCB_INITIALIZED, &dlci->port.flags)) {
2974 if (C_HUPCL(tty))
2975 tty_port_lower_dtr_rts(&dlci->port);
2976 }
2977 tty_port_close_end(&dlci->port, tty);
2978 tty_port_tty_set(&dlci->port, NULL);
2979 return;
2980}
2981
2982static void gsmtty_hangup(struct tty_struct *tty)
2983{
2984 struct gsm_dlci *dlci = tty->driver_data;
2985 if (dlci->state == DLCI_CLOSED)
2986 return;
2987 tty_port_hangup(&dlci->port);
2988 gsm_dlci_begin_close(dlci);
2989}
2990
2991static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
2992 int len)
2993{
2994 int sent;
2995 struct gsm_dlci *dlci = tty->driver_data;
2996 if (dlci->state == DLCI_CLOSED)
2997 return -EINVAL;
2998 /* Stuff the bytes into the fifo queue */
2999 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
3000 /* Need to kick the channel */
3001 gsm_dlci_data_kick(dlci);
3002 return sent;
3003}
3004
3005static int gsmtty_write_room(struct tty_struct *tty)
3006{
3007 struct gsm_dlci *dlci = tty->driver_data;
3008 if (dlci->state == DLCI_CLOSED)
3009 return -EINVAL;
3010 return TX_SIZE - kfifo_len(dlci->fifo);
3011}
3012
3013static int gsmtty_chars_in_buffer(struct tty_struct *tty)
3014{
3015 struct gsm_dlci *dlci = tty->driver_data;
3016 if (dlci->state == DLCI_CLOSED)
3017 return -EINVAL;
3018 return kfifo_len(dlci->fifo);
3019}
3020
3021static void gsmtty_flush_buffer(struct tty_struct *tty)
3022{
3023 struct gsm_dlci *dlci = tty->driver_data;
3024 if (dlci->state == DLCI_CLOSED)
3025 return;
3026 /* Caution needed: If we implement reliable transport classes
3027 then the data being transmitted can't simply be junked once
3028 it has first hit the stack. Until then we can just blow it
3029 away */
3030 kfifo_reset(dlci->fifo);
3031 /* Need to unhook this DLCI from the transmit queue logic */
3032}
3033
3034static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3035{
3036 /* The FIFO handles the queue so the kernel will do the right
3037 thing waiting on chars_in_buffer before calling us. No work
3038 to do here */
3039}
3040
3041static int gsmtty_tiocmget(struct tty_struct *tty)
3042{
3043 struct gsm_dlci *dlci = tty->driver_data;
3044 if (dlci->state == DLCI_CLOSED)
3045 return -EINVAL;
3046 return dlci->modem_rx;
3047}
3048
3049static int gsmtty_tiocmset(struct tty_struct *tty,
3050 unsigned int set, unsigned int clear)
3051{
3052 struct gsm_dlci *dlci = tty->driver_data;
3053 unsigned int modem_tx = dlci->modem_tx;
3054
3055 if (dlci->state == DLCI_CLOSED)
3056 return -EINVAL;
3057 modem_tx &= ~clear;
3058 modem_tx |= set;
3059
3060 if (modem_tx != dlci->modem_tx) {
3061 dlci->modem_tx = modem_tx;
3062 return gsmtty_modem_update(dlci, 0);
3063 }
3064 return 0;
3065}
3066
3067
3068static int gsmtty_ioctl(struct tty_struct *tty,
3069 unsigned int cmd, unsigned long arg)
3070{
3071 struct gsm_dlci *dlci = tty->driver_data;
3072 struct gsm_netconfig nc;
3073 int index;
3074
3075 if (dlci->state == DLCI_CLOSED)
3076 return -EINVAL;
3077 switch (cmd) {
3078 case GSMIOC_ENABLE_NET:
3079 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3080 return -EFAULT;
3081 nc.if_name[IFNAMSIZ-1] = '\0';
3082 /* return net interface index or error code */
3083 mutex_lock(&dlci->mutex);
3084 index = gsm_create_network(dlci, &nc);
3085 mutex_unlock(&dlci->mutex);
3086 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3087 return -EFAULT;
3088 return index;
3089 case GSMIOC_DISABLE_NET:
3090 if (!capable(CAP_NET_ADMIN))
3091 return -EPERM;
3092 mutex_lock(&dlci->mutex);
3093 gsm_destroy_network(dlci);
3094 mutex_unlock(&dlci->mutex);
3095 return 0;
3096 default:
3097 return -ENOIOCTLCMD;
3098 }
3099}
3100
3101static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3102{
3103 struct gsm_dlci *dlci = tty->driver_data;
3104 if (dlci->state == DLCI_CLOSED)
3105 return;
3106 /* For the moment its fixed. In actual fact the speed information
3107 for the virtual channel can be propogated in both directions by
3108 the RPN control message. This however rapidly gets nasty as we
3109 then have to remap modem signals each way according to whether
3110 our virtual cable is null modem etc .. */
3111 tty_termios_copy_hw(&tty->termios, old);
3112}
3113
3114static void gsmtty_throttle(struct tty_struct *tty)
3115{
3116 struct gsm_dlci *dlci = tty->driver_data;
3117 if (dlci->state == DLCI_CLOSED)
3118 return;
3119 if (C_CRTSCTS(tty))
3120 dlci->modem_tx &= ~TIOCM_DTR;
3121 dlci->throttled = 1;
3122 /* Send an MSC with DTR cleared */
3123 gsmtty_modem_update(dlci, 0);
3124}
3125
3126static void gsmtty_unthrottle(struct tty_struct *tty)
3127{
3128 struct gsm_dlci *dlci = tty->driver_data;
3129 if (dlci->state == DLCI_CLOSED)
3130 return;
3131 if (C_CRTSCTS(tty))
3132 dlci->modem_tx |= TIOCM_DTR;
3133 dlci->throttled = 0;
3134 /* Send an MSC with DTR set */
3135 gsmtty_modem_update(dlci, 0);
3136}
3137
3138static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3139{
3140 struct gsm_dlci *dlci = tty->driver_data;
3141 int encode = 0; /* Off */
3142 if (dlci->state == DLCI_CLOSED)
3143 return -EINVAL;
3144
3145 if (state == -1) /* "On indefinitely" - we can't encode this
3146 properly */
3147 encode = 0x0F;
3148 else if (state > 0) {
3149 encode = state / 200; /* mS to encoding */
3150 if (encode > 0x0F)
3151 encode = 0x0F; /* Best effort */
3152 }
3153 return gsmtty_modem_update(dlci, encode);
3154}
3155
3156static void gsmtty_cleanup(struct tty_struct *tty)
3157{
3158 struct gsm_dlci *dlci = tty->driver_data;
3159 struct gsm_mux *gsm = dlci->gsm;
3160
3161 dlci_put(dlci);
3162 dlci_put(gsm->dlci[0]);
3163 mux_put(gsm);
3164}
3165
3166/* Virtual ttys for the demux */
3167static const struct tty_operations gsmtty_ops = {
3168 .install = gsmtty_install,
3169 .open = gsmtty_open,
3170 .close = gsmtty_close,
3171 .write = gsmtty_write,
3172 .write_room = gsmtty_write_room,
3173 .chars_in_buffer = gsmtty_chars_in_buffer,
3174 .flush_buffer = gsmtty_flush_buffer,
3175 .ioctl = gsmtty_ioctl,
3176 .throttle = gsmtty_throttle,
3177 .unthrottle = gsmtty_unthrottle,
3178 .set_termios = gsmtty_set_termios,
3179 .hangup = gsmtty_hangup,
3180 .wait_until_sent = gsmtty_wait_until_sent,
3181 .tiocmget = gsmtty_tiocmget,
3182 .tiocmset = gsmtty_tiocmset,
3183 .break_ctl = gsmtty_break_ctl,
3184 .cleanup = gsmtty_cleanup,
3185};
3186
3187
3188
3189static int __init gsm_init(void)
3190{
3191 /* Fill in our line protocol discipline, and register it */
3192 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3193 if (status != 0) {
3194 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3195 status);
3196 return status;
3197 }
3198
3199 gsm_tty_driver = alloc_tty_driver(256);
3200 if (!gsm_tty_driver) {
3201 tty_unregister_ldisc(N_GSM0710);
3202 pr_err("gsm_init: tty allocation failed.\n");
3203 return -EINVAL;
3204 }
3205 gsm_tty_driver->driver_name = "gsmtty";
3206 gsm_tty_driver->name = "gsmtty";
3207 gsm_tty_driver->major = 0; /* Dynamic */
3208 gsm_tty_driver->minor_start = 0;
3209 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3210 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3211 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3212 | TTY_DRIVER_HARDWARE_BREAK;
3213 gsm_tty_driver->init_termios = tty_std_termios;
3214 /* Fixme */
3215 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3216 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3217
3218 spin_lock_init(&gsm_mux_lock);
3219
3220 if (tty_register_driver(gsm_tty_driver)) {
3221 put_tty_driver(gsm_tty_driver);
3222 tty_unregister_ldisc(N_GSM0710);
3223 pr_err("gsm_init: tty registration failed.\n");
3224 return -EBUSY;
3225 }
3226 pr_debug("gsm_init: loaded as %d,%d.\n",
3227 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3228 return 0;
3229}
3230
3231static void __exit gsm_exit(void)
3232{
3233 int status = tty_unregister_ldisc(N_GSM0710);
3234 if (status != 0)
3235 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3236 status);
3237 tty_unregister_driver(gsm_tty_driver);
3238 put_tty_driver(gsm_tty_driver);
3239}
3240
3241module_init(gsm_init);
3242module_exit(gsm_exit);
3243
3244
3245MODULE_LICENSE("GPL");
3246MODULE_ALIAS_LDISC(N_GSM0710);