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