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