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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#include "tty.h"
54
55static int debug;
56module_param(debug, int, 0600);
57
58/* Defaults: these are from the specification */
59
60#define T1 10 /* 100mS */
61#define T2 34 /* 333mS */
62#define N2 3 /* Retry 3 times */
63
64/* Use long timers for testing at low speed with debug on */
65#ifdef DEBUG_TIMING
66#define T1 100
67#define T2 200
68#endif
69
70/*
71 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
72 * limits so this is plenty
73 */
74#define MAX_MRU 1500
75#define MAX_MTU 1500
76#define GSM_NET_TX_TIMEOUT (HZ*10)
77
78/*
79 * struct gsm_mux_net - network interface
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 /* Method for the receiver side */
226 void (*receive)(struct gsm_mux *gsm, u8 ch);
227
228 /* Link Layer */
229 unsigned int mru;
230 unsigned int mtu;
231 int initiator; /* Did we initiate connection */
232 bool dead; /* Has the mux been shut down */
233 struct gsm_dlci *dlci[NUM_DLCI];
234 bool constipated; /* Asked by remote to shut up */
235
236 spinlock_t tx_lock;
237 unsigned int tx_bytes; /* TX data outstanding */
238#define TX_THRESH_HI 8192
239#define TX_THRESH_LO 2048
240 struct list_head tx_list; /* Pending data packets */
241
242 /* Control messages */
243 struct timer_list t2_timer; /* Retransmit timer for commands */
244 int cretries; /* Command retry counter */
245 struct gsm_control *pending_cmd;/* Our current pending command */
246 spinlock_t control_lock; /* Protects the pending command */
247
248 /* Configuration */
249 int adaption; /* 1 or 2 supported */
250 u8 ftype; /* UI or UIH */
251 int t1, t2; /* Timers in 1/100th of a sec */
252 int n2; /* Retry count */
253
254 /* Statistics (not currently exposed) */
255 unsigned long bad_fcs;
256 unsigned long malformed;
257 unsigned long io_error;
258 unsigned long bad_size;
259 unsigned long unsupported;
260};
261
262
263/*
264 * Mux objects - needed so that we can translate a tty index into the
265 * relevant mux and DLCI.
266 */
267
268#define MAX_MUX 4 /* 256 minors */
269static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
270static DEFINE_SPINLOCK(gsm_mux_lock);
271
272static struct tty_driver *gsm_tty_driver;
273
274/*
275 * This section of the driver logic implements the GSM encodings
276 * both the basic and the 'advanced'. Reliable transport is not
277 * supported.
278 */
279
280#define CR 0x02
281#define EA 0x01
282#define PF 0x10
283
284/* I is special: the rest are ..*/
285#define RR 0x01
286#define UI 0x03
287#define RNR 0x05
288#define REJ 0x09
289#define DM 0x0F
290#define SABM 0x2F
291#define DISC 0x43
292#define UA 0x63
293#define UIH 0xEF
294
295/* Channel commands */
296#define CMD_NSC 0x09
297#define CMD_TEST 0x11
298#define CMD_PSC 0x21
299#define CMD_RLS 0x29
300#define CMD_FCOFF 0x31
301#define CMD_PN 0x41
302#define CMD_RPN 0x49
303#define CMD_FCON 0x51
304#define CMD_CLD 0x61
305#define CMD_SNC 0x69
306#define CMD_MSC 0x71
307
308/* Virtual modem bits */
309#define MDM_FC 0x01
310#define MDM_RTC 0x02
311#define MDM_RTR 0x04
312#define MDM_IC 0x20
313#define MDM_DV 0x40
314
315#define GSM0_SOF 0xF9
316#define GSM1_SOF 0x7E
317#define GSM1_ESCAPE 0x7D
318#define GSM1_ESCAPE_BITS 0x20
319#define XON 0x11
320#define XOFF 0x13
321
322static const struct tty_port_operations gsm_port_ops;
323
324/*
325 * CRC table for GSM 0710
326 */
327
328static const u8 gsm_fcs8[256] = {
329 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
330 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
331 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
332 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
333 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
334 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
335 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
336 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
337 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
338 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
339 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
340 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
341 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
342 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
343 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
344 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
345 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
346 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
347 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
348 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
349 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
350 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
351 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
352 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
353 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
354 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
355 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
356 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
357 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
358 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
359 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
360 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
361};
362
363#define INIT_FCS 0xFF
364#define GOOD_FCS 0xCF
365
366static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len);
367
368/**
369 * gsm_fcs_add - update FCS
370 * @fcs: Current FCS
371 * @c: Next data
372 *
373 * Update the FCS to include c. Uses the algorithm in the specification
374 * notes.
375 */
376
377static inline u8 gsm_fcs_add(u8 fcs, u8 c)
378{
379 return gsm_fcs8[fcs ^ c];
380}
381
382/**
383 * gsm_fcs_add_block - update FCS for a block
384 * @fcs: Current FCS
385 * @c: buffer of data
386 * @len: length of buffer
387 *
388 * Update the FCS to include c. Uses the algorithm in the specification
389 * notes.
390 */
391
392static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
393{
394 while (len--)
395 fcs = gsm_fcs8[fcs ^ *c++];
396 return fcs;
397}
398
399/**
400 * gsm_read_ea - read a byte into an EA
401 * @val: variable holding value
402 * @c: byte going into the EA
403 *
404 * Processes one byte of an EA. Updates the passed variable
405 * and returns 1 if the EA is now completely read
406 */
407
408static int gsm_read_ea(unsigned int *val, u8 c)
409{
410 /* Add the next 7 bits into the value */
411 *val <<= 7;
412 *val |= c >> 1;
413 /* Was this the last byte of the EA 1 = yes*/
414 return c & EA;
415}
416
417/**
418 * gsm_encode_modem - encode modem data bits
419 * @dlci: DLCI to encode from
420 *
421 * Returns the correct GSM encoded modem status bits (6 bit field) for
422 * the current status of the DLCI and attached tty object
423 */
424
425static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
426{
427 u8 modembits = 0;
428 /* FC is true flow control not modem bits */
429 if (dlci->throttled)
430 modembits |= MDM_FC;
431 if (dlci->modem_tx & TIOCM_DTR)
432 modembits |= MDM_RTC;
433 if (dlci->modem_tx & TIOCM_RTS)
434 modembits |= MDM_RTR;
435 if (dlci->modem_tx & TIOCM_RI)
436 modembits |= MDM_IC;
437 if (dlci->modem_tx & TIOCM_CD)
438 modembits |= MDM_DV;
439 return modembits;
440}
441
442/**
443 * gsm_print_packet - display a frame for debug
444 * @hdr: header to print before decode
445 * @addr: address EA from the frame
446 * @cr: C/R bit from the frame
447 * @control: control including PF bit
448 * @data: following data bytes
449 * @dlen: length of data
450 *
451 * Displays a packet in human readable format for debugging purposes. The
452 * style is based on amateur radio LAP-B dump display.
453 */
454
455static void gsm_print_packet(const char *hdr, int addr, int cr,
456 u8 control, const u8 *data, int dlen)
457{
458 if (!(debug & 1))
459 return;
460
461 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
462
463 switch (control & ~PF) {
464 case SABM:
465 pr_cont("SABM");
466 break;
467 case UA:
468 pr_cont("UA");
469 break;
470 case DISC:
471 pr_cont("DISC");
472 break;
473 case DM:
474 pr_cont("DM");
475 break;
476 case UI:
477 pr_cont("UI");
478 break;
479 case UIH:
480 pr_cont("UIH");
481 break;
482 default:
483 if (!(control & 0x01)) {
484 pr_cont("I N(S)%d N(R)%d",
485 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
486 } else switch (control & 0x0F) {
487 case RR:
488 pr_cont("RR(%d)", (control & 0xE0) >> 5);
489 break;
490 case RNR:
491 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
492 break;
493 case REJ:
494 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
495 break;
496 default:
497 pr_cont("[%02X]", control);
498 }
499 }
500
501 if (control & PF)
502 pr_cont("(P)");
503 else
504 pr_cont("(F)");
505
506 print_hex_dump_bytes("", DUMP_PREFIX_NONE, data, dlen);
507}
508
509
510/*
511 * Link level transmission side
512 */
513
514/**
515 * gsm_stuff_frame - bytestuff a packet
516 * @input: input buffer
517 * @output: output buffer
518 * @len: length of input
519 *
520 * Expand a buffer by bytestuffing it. The worst case size change
521 * is doubling and the caller is responsible for handing out
522 * suitable sized buffers.
523 */
524
525static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
526{
527 int olen = 0;
528 while (len--) {
529 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
530 || *input == XON || *input == XOFF) {
531 *output++ = GSM1_ESCAPE;
532 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
533 olen++;
534 } else
535 *output++ = *input++;
536 olen++;
537 }
538 return olen;
539}
540
541/**
542 * gsm_send - send a control frame
543 * @gsm: our GSM mux
544 * @addr: address for control frame
545 * @cr: command/response bit
546 * @control: control byte including PF bit
547 *
548 * Format up and transmit a control frame. These do not go via the
549 * queueing logic as they should be transmitted ahead of data when
550 * they are needed.
551 *
552 * FIXME: Lock versus data TX path
553 */
554
555static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
556{
557 int len;
558 u8 cbuf[10];
559 u8 ibuf[3];
560
561 switch (gsm->encoding) {
562 case 0:
563 cbuf[0] = GSM0_SOF;
564 cbuf[1] = (addr << 2) | (cr << 1) | EA;
565 cbuf[2] = control;
566 cbuf[3] = EA; /* Length of data = 0 */
567 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
568 cbuf[5] = GSM0_SOF;
569 len = 6;
570 break;
571 case 1:
572 case 2:
573 /* Control frame + packing (but not frame stuffing) in mode 1 */
574 ibuf[0] = (addr << 2) | (cr << 1) | EA;
575 ibuf[1] = control;
576 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
577 /* Stuffing may double the size worst case */
578 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
579 /* Now add the SOF markers */
580 cbuf[0] = GSM1_SOF;
581 cbuf[len + 1] = GSM1_SOF;
582 /* FIXME: we can omit the lead one in many cases */
583 len += 2;
584 break;
585 default:
586 WARN_ON(1);
587 return;
588 }
589 gsmld_output(gsm, cbuf, len);
590 gsm_print_packet("-->", addr, cr, control, NULL, 0);
591}
592
593/**
594 * gsm_response - send a control response
595 * @gsm: our GSM mux
596 * @addr: address for control frame
597 * @control: control byte including PF bit
598 *
599 * Format up and transmit a link level response frame.
600 */
601
602static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
603{
604 gsm_send(gsm, addr, 0, control);
605}
606
607/**
608 * gsm_command - send a control command
609 * @gsm: our GSM mux
610 * @addr: address for control frame
611 * @control: control byte including PF bit
612 *
613 * Format up and transmit a link level command frame.
614 */
615
616static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
617{
618 gsm_send(gsm, addr, 1, control);
619}
620
621/* Data transmission */
622
623#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
624
625/**
626 * gsm_data_alloc - allocate data frame
627 * @gsm: GSM mux
628 * @addr: DLCI address
629 * @len: length excluding header and FCS
630 * @ctrl: control byte
631 *
632 * Allocate a new data buffer for sending frames with data. Space is left
633 * at the front for header bytes but that is treated as an implementation
634 * detail and not for the high level code to use
635 */
636
637static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
638 u8 ctrl)
639{
640 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
641 GFP_ATOMIC);
642 if (m == NULL)
643 return NULL;
644 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
645 m->len = len;
646 m->addr = addr;
647 m->ctrl = ctrl;
648 INIT_LIST_HEAD(&m->list);
649 return m;
650}
651
652/**
653 * gsm_data_kick - poke the queue
654 * @gsm: GSM Mux
655 * @dlci: DLCI sending the data
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 (gsmld_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 * @clen: command length
1011 *
1012 * Used when a modem control message or line state inline in adaption
1013 * layer 2 is processed. Sort out the local modem state and throttles
1014 */
1015
1016static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1017 u32 modem, int clen)
1018{
1019 int mlines = 0;
1020 u8 brk = 0;
1021 int fc;
1022
1023 /* The modem status command can either contain one octet (v.24 signals)
1024 or two octets (v.24 signals + break signals). The length field will
1025 either be 2 or 3 respectively. This is specified in section
1026 5.4.6.3.7 of the 27.010 mux spec. */
1027
1028 if (clen == 2)
1029 modem = modem & 0x7f;
1030 else {
1031 brk = modem & 0x7f;
1032 modem = (modem >> 7) & 0x7f;
1033 }
1034
1035 /* Flow control/ready to communicate */
1036 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1037 if (fc && !dlci->constipated) {
1038 /* Need to throttle our output on this device */
1039 dlci->constipated = true;
1040 } else if (!fc && dlci->constipated) {
1041 dlci->constipated = false;
1042 gsm_dlci_data_kick(dlci);
1043 }
1044
1045 /* Map modem bits */
1046 if (modem & MDM_RTC)
1047 mlines |= TIOCM_DSR | TIOCM_DTR;
1048 if (modem & MDM_RTR)
1049 mlines |= TIOCM_RTS | TIOCM_CTS;
1050 if (modem & MDM_IC)
1051 mlines |= TIOCM_RI;
1052 if (modem & MDM_DV)
1053 mlines |= TIOCM_CD;
1054
1055 /* Carrier drop -> hangup */
1056 if (tty) {
1057 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1058 if (!C_CLOCAL(tty))
1059 tty_hangup(tty);
1060 }
1061 if (brk & 0x01)
1062 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1063 dlci->modem_rx = mlines;
1064}
1065
1066/**
1067 * gsm_control_modem - modem status received
1068 * @gsm: GSM channel
1069 * @data: data following command
1070 * @clen: command length
1071 *
1072 * We have received a modem status control message. This is used by
1073 * the GSM mux protocol to pass virtual modem line status and optionally
1074 * to indicate break signals. Unpack it, convert to Linux representation
1075 * and if need be stuff a break message down the tty.
1076 */
1077
1078static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
1079{
1080 unsigned int addr = 0;
1081 unsigned int modem = 0;
1082 unsigned int brk = 0;
1083 struct gsm_dlci *dlci;
1084 int len = clen;
1085 const u8 *dp = data;
1086 struct tty_struct *tty;
1087
1088 while (gsm_read_ea(&addr, *dp++) == 0) {
1089 len--;
1090 if (len == 0)
1091 return;
1092 }
1093 /* Must be at least one byte following the EA */
1094 len--;
1095 if (len <= 0)
1096 return;
1097
1098 addr >>= 1;
1099 /* Closed port, or invalid ? */
1100 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1101 return;
1102 dlci = gsm->dlci[addr];
1103
1104 while (gsm_read_ea(&modem, *dp++) == 0) {
1105 len--;
1106 if (len == 0)
1107 return;
1108 }
1109 len--;
1110 if (len > 0) {
1111 while (gsm_read_ea(&brk, *dp++) == 0) {
1112 len--;
1113 if (len == 0)
1114 return;
1115 }
1116 modem <<= 7;
1117 modem |= (brk & 0x7f);
1118 }
1119 tty = tty_port_tty_get(&dlci->port);
1120 gsm_process_modem(tty, dlci, modem, clen);
1121 if (tty) {
1122 tty_wakeup(tty);
1123 tty_kref_put(tty);
1124 }
1125 gsm_control_reply(gsm, CMD_MSC, data, clen);
1126}
1127
1128/**
1129 * gsm_control_rls - remote line status
1130 * @gsm: GSM channel
1131 * @data: data bytes
1132 * @clen: data length
1133 *
1134 * The modem sends us a two byte message on the control channel whenever
1135 * it wishes to send us an error state from the virtual link. Stuff
1136 * this into the uplink tty if present
1137 */
1138
1139static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen)
1140{
1141 struct tty_port *port;
1142 unsigned int addr = 0;
1143 u8 bits;
1144 int len = clen;
1145 const u8 *dp = data;
1146
1147 while (gsm_read_ea(&addr, *dp++) == 0) {
1148 len--;
1149 if (len == 0)
1150 return;
1151 }
1152 /* Must be at least one byte following ea */
1153 len--;
1154 if (len <= 0)
1155 return;
1156 addr >>= 1;
1157 /* Closed port, or invalid ? */
1158 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1159 return;
1160 /* No error ? */
1161 bits = *dp;
1162 if ((bits & 1) == 0)
1163 return;
1164
1165 port = &gsm->dlci[addr]->port;
1166
1167 if (bits & 2)
1168 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1169 if (bits & 4)
1170 tty_insert_flip_char(port, 0, TTY_PARITY);
1171 if (bits & 8)
1172 tty_insert_flip_char(port, 0, TTY_FRAME);
1173
1174 tty_flip_buffer_push(port);
1175
1176 gsm_control_reply(gsm, CMD_RLS, data, clen);
1177}
1178
1179static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1180
1181/**
1182 * gsm_control_message - DLCI 0 control processing
1183 * @gsm: our GSM mux
1184 * @command: the command EA
1185 * @data: data beyond the command/length EAs
1186 * @clen: length
1187 *
1188 * Input processor for control messages from the other end of the link.
1189 * Processes the incoming request and queues a response frame or an
1190 * NSC response if not supported
1191 */
1192
1193static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1194 const u8 *data, int clen)
1195{
1196 u8 buf[1];
1197 unsigned long flags;
1198
1199 switch (command) {
1200 case CMD_CLD: {
1201 struct gsm_dlci *dlci = gsm->dlci[0];
1202 /* Modem wishes to close down */
1203 if (dlci) {
1204 dlci->dead = true;
1205 gsm->dead = true;
1206 gsm_dlci_begin_close(dlci);
1207 }
1208 }
1209 break;
1210 case CMD_TEST:
1211 /* Modem wishes to test, reply with the data */
1212 gsm_control_reply(gsm, CMD_TEST, data, clen);
1213 break;
1214 case CMD_FCON:
1215 /* Modem can accept data again */
1216 gsm->constipated = false;
1217 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1218 /* Kick the link in case it is idling */
1219 spin_lock_irqsave(&gsm->tx_lock, flags);
1220 gsm_data_kick(gsm, NULL);
1221 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1222 break;
1223 case CMD_FCOFF:
1224 /* Modem wants us to STFU */
1225 gsm->constipated = true;
1226 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1227 break;
1228 case CMD_MSC:
1229 /* Out of band modem line change indicator for a DLCI */
1230 gsm_control_modem(gsm, data, clen);
1231 break;
1232 case CMD_RLS:
1233 /* Out of band error reception for a DLCI */
1234 gsm_control_rls(gsm, data, clen);
1235 break;
1236 case CMD_PSC:
1237 /* Modem wishes to enter power saving state */
1238 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1239 break;
1240 /* Optional unsupported commands */
1241 case CMD_PN: /* Parameter negotiation */
1242 case CMD_RPN: /* Remote port negotiation */
1243 case CMD_SNC: /* Service negotiation command */
1244 default:
1245 /* Reply to bad commands with an NSC */
1246 buf[0] = command;
1247 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1248 break;
1249 }
1250}
1251
1252/**
1253 * gsm_control_response - process a response to our control
1254 * @gsm: our GSM mux
1255 * @command: the command (response) EA
1256 * @data: data beyond the command/length EA
1257 * @clen: length
1258 *
1259 * Process a response to an outstanding command. We only allow a single
1260 * control message in flight so this is fairly easy. All the clean up
1261 * is done by the caller, we just update the fields, flag it as done
1262 * and return
1263 */
1264
1265static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1266 const u8 *data, int clen)
1267{
1268 struct gsm_control *ctrl;
1269 unsigned long flags;
1270
1271 spin_lock_irqsave(&gsm->control_lock, flags);
1272
1273 ctrl = gsm->pending_cmd;
1274 /* Does the reply match our command */
1275 command |= 1;
1276 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1277 /* Our command was replied to, kill the retry timer */
1278 del_timer(&gsm->t2_timer);
1279 gsm->pending_cmd = NULL;
1280 /* Rejected by the other end */
1281 if (command == CMD_NSC)
1282 ctrl->error = -EOPNOTSUPP;
1283 ctrl->done = 1;
1284 wake_up(&gsm->event);
1285 }
1286 spin_unlock_irqrestore(&gsm->control_lock, flags);
1287}
1288
1289/**
1290 * gsm_control_transmit - send control packet
1291 * @gsm: gsm mux
1292 * @ctrl: frame to send
1293 *
1294 * Send out a pending control command (called under control lock)
1295 */
1296
1297static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1298{
1299 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1300 if (msg == NULL)
1301 return;
1302 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1303 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1304 gsm_data_queue(gsm->dlci[0], msg);
1305}
1306
1307/**
1308 * gsm_control_retransmit - retransmit a control frame
1309 * @t: timer contained in our gsm object
1310 *
1311 * Called off the T2 timer expiry in order to retransmit control frames
1312 * that have been lost in the system somewhere. The control_lock protects
1313 * us from colliding with another sender or a receive completion event.
1314 * In that situation the timer may still occur in a small window but
1315 * gsm->pending_cmd will be NULL and we just let the timer expire.
1316 */
1317
1318static void gsm_control_retransmit(struct timer_list *t)
1319{
1320 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer);
1321 struct gsm_control *ctrl;
1322 unsigned long flags;
1323 spin_lock_irqsave(&gsm->control_lock, flags);
1324 ctrl = gsm->pending_cmd;
1325 if (ctrl) {
1326 gsm->cretries--;
1327 if (gsm->cretries == 0) {
1328 gsm->pending_cmd = NULL;
1329 ctrl->error = -ETIMEDOUT;
1330 ctrl->done = 1;
1331 spin_unlock_irqrestore(&gsm->control_lock, flags);
1332 wake_up(&gsm->event);
1333 return;
1334 }
1335 gsm_control_transmit(gsm, ctrl);
1336 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1337 }
1338 spin_unlock_irqrestore(&gsm->control_lock, flags);
1339}
1340
1341/**
1342 * gsm_control_send - send a control frame on DLCI 0
1343 * @gsm: the GSM channel
1344 * @command: command to send including CR bit
1345 * @data: bytes of data (must be kmalloced)
1346 * @clen: length of the block to send
1347 *
1348 * Queue and dispatch a control command. Only one command can be
1349 * active at a time. In theory more can be outstanding but the matching
1350 * gets really complicated so for now stick to one outstanding.
1351 */
1352
1353static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1354 unsigned int command, u8 *data, int clen)
1355{
1356 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1357 GFP_KERNEL);
1358 unsigned long flags;
1359 if (ctrl == NULL)
1360 return NULL;
1361retry:
1362 wait_event(gsm->event, gsm->pending_cmd == NULL);
1363 spin_lock_irqsave(&gsm->control_lock, flags);
1364 if (gsm->pending_cmd != NULL) {
1365 spin_unlock_irqrestore(&gsm->control_lock, flags);
1366 goto retry;
1367 }
1368 ctrl->cmd = command;
1369 ctrl->data = data;
1370 ctrl->len = clen;
1371 gsm->pending_cmd = ctrl;
1372
1373 /* If DLCI0 is in ADM mode skip retries, it won't respond */
1374 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
1375 gsm->cretries = 1;
1376 else
1377 gsm->cretries = gsm->n2;
1378
1379 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1380 gsm_control_transmit(gsm, ctrl);
1381 spin_unlock_irqrestore(&gsm->control_lock, flags);
1382 return ctrl;
1383}
1384
1385/**
1386 * gsm_control_wait - wait for a control to finish
1387 * @gsm: GSM mux
1388 * @control: control we are waiting on
1389 *
1390 * Waits for the control to complete or time out. Frees any used
1391 * resources and returns 0 for success, or an error if the remote
1392 * rejected or ignored the request.
1393 */
1394
1395static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1396{
1397 int err;
1398 wait_event(gsm->event, control->done == 1);
1399 err = control->error;
1400 kfree(control);
1401 return err;
1402}
1403
1404
1405/*
1406 * DLCI level handling: Needs krefs
1407 */
1408
1409/*
1410 * State transitions and timers
1411 */
1412
1413/**
1414 * gsm_dlci_close - a DLCI has closed
1415 * @dlci: DLCI that closed
1416 *
1417 * Perform processing when moving a DLCI into closed state. If there
1418 * is an attached tty this is hung up
1419 */
1420
1421static void gsm_dlci_close(struct gsm_dlci *dlci)
1422{
1423 del_timer(&dlci->t1);
1424 if (debug & 8)
1425 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1426 dlci->state = DLCI_CLOSED;
1427 if (dlci->addr != 0) {
1428 tty_port_tty_hangup(&dlci->port, false);
1429 kfifo_reset(&dlci->fifo);
1430 } else
1431 dlci->gsm->dead = true;
1432 wake_up(&dlci->gsm->event);
1433 /* A DLCI 0 close is a MUX termination so we need to kick that
1434 back to userspace somehow */
1435}
1436
1437/**
1438 * gsm_dlci_open - a DLCI has opened
1439 * @dlci: DLCI that opened
1440 *
1441 * Perform processing when moving a DLCI into open state.
1442 */
1443
1444static void gsm_dlci_open(struct gsm_dlci *dlci)
1445{
1446 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1447 open -> open */
1448 del_timer(&dlci->t1);
1449 /* This will let a tty open continue */
1450 dlci->state = DLCI_OPEN;
1451 if (debug & 8)
1452 pr_debug("DLCI %d goes open.\n", dlci->addr);
1453 wake_up(&dlci->gsm->event);
1454}
1455
1456/**
1457 * gsm_dlci_t1 - T1 timer expiry
1458 * @t: timer contained in the DLCI that opened
1459 *
1460 * The T1 timer handles retransmits of control frames (essentially of
1461 * SABM and DISC). We resend the command until the retry count runs out
1462 * in which case an opening port goes back to closed and a closing port
1463 * is simply put into closed state (any further frames from the other
1464 * end will get a DM response)
1465 *
1466 * Some control dlci can stay in ADM mode with other dlci working just
1467 * fine. In that case we can just keep the control dlci open after the
1468 * DLCI_OPENING retries time out.
1469 */
1470
1471static void gsm_dlci_t1(struct timer_list *t)
1472{
1473 struct gsm_dlci *dlci = from_timer(dlci, t, t1);
1474 struct gsm_mux *gsm = dlci->gsm;
1475
1476 switch (dlci->state) {
1477 case DLCI_OPENING:
1478 dlci->retries--;
1479 if (dlci->retries) {
1480 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1481 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1482 } else if (!dlci->addr && gsm->control == (DM | PF)) {
1483 if (debug & 8)
1484 pr_info("DLCI %d opening in ADM mode.\n",
1485 dlci->addr);
1486 dlci->mode = DLCI_MODE_ADM;
1487 gsm_dlci_open(dlci);
1488 } else {
1489 gsm_dlci_close(dlci);
1490 }
1491
1492 break;
1493 case DLCI_CLOSING:
1494 dlci->retries--;
1495 if (dlci->retries) {
1496 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1497 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1498 } else
1499 gsm_dlci_close(dlci);
1500 break;
1501 default:
1502 pr_debug("%s: unhandled state: %d\n", __func__, dlci->state);
1503 break;
1504 }
1505}
1506
1507/**
1508 * gsm_dlci_begin_open - start channel open procedure
1509 * @dlci: DLCI to open
1510 *
1511 * Commence opening a DLCI from the Linux side. We issue SABM messages
1512 * to the modem which should then reply with a UA or ADM, at which point
1513 * we will move into open state. Opening is done asynchronously with retry
1514 * running off timers and the responses.
1515 */
1516
1517static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1518{
1519 struct gsm_mux *gsm = dlci->gsm;
1520 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1521 return;
1522 dlci->retries = gsm->n2;
1523 dlci->state = DLCI_OPENING;
1524 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1525 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1526}
1527
1528/**
1529 * gsm_dlci_begin_close - start channel open procedure
1530 * @dlci: DLCI to open
1531 *
1532 * Commence closing a DLCI from the Linux side. We issue DISC messages
1533 * to the modem which should then reply with a UA, at which point we
1534 * will move into closed state. Closing is done asynchronously with retry
1535 * off timers. We may also receive a DM reply from the other end which
1536 * indicates the channel was already closed.
1537 */
1538
1539static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1540{
1541 struct gsm_mux *gsm = dlci->gsm;
1542 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1543 return;
1544 dlci->retries = gsm->n2;
1545 dlci->state = DLCI_CLOSING;
1546 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1547 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1548}
1549
1550/**
1551 * gsm_dlci_data - data arrived
1552 * @dlci: channel
1553 * @data: block of bytes received
1554 * @clen: length of received block
1555 *
1556 * A UI or UIH frame has arrived which contains data for a channel
1557 * other than the control channel. If the relevant virtual tty is
1558 * open we shovel the bits down it, if not we drop them.
1559 */
1560
1561static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
1562{
1563 /* krefs .. */
1564 struct tty_port *port = &dlci->port;
1565 struct tty_struct *tty;
1566 unsigned int modem = 0;
1567 int len = clen;
1568
1569 if (debug & 16)
1570 pr_debug("%d bytes for tty\n", len);
1571 switch (dlci->adaption) {
1572 /* Unsupported types */
1573 case 4: /* Packetised interruptible data */
1574 break;
1575 case 3: /* Packetised uininterruptible voice/data */
1576 break;
1577 case 2: /* Asynchronous serial with line state in each frame */
1578 while (gsm_read_ea(&modem, *data++) == 0) {
1579 len--;
1580 if (len == 0)
1581 return;
1582 }
1583 tty = tty_port_tty_get(port);
1584 if (tty) {
1585 gsm_process_modem(tty, dlci, modem, clen);
1586 tty_kref_put(tty);
1587 }
1588 fallthrough;
1589 case 1: /* Line state will go via DLCI 0 controls only */
1590 default:
1591 tty_insert_flip_string(port, data, len);
1592 tty_flip_buffer_push(port);
1593 }
1594}
1595
1596/**
1597 * gsm_dlci_command - data arrived on control channel
1598 * @dlci: channel
1599 * @data: block of bytes received
1600 * @len: length of received block
1601 *
1602 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1603 * control channel. This should contain a command EA followed by
1604 * control data bytes. The command EA contains a command/response bit
1605 * and we divide up the work accordingly.
1606 */
1607
1608static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
1609{
1610 /* See what command is involved */
1611 unsigned int command = 0;
1612 while (len-- > 0) {
1613 if (gsm_read_ea(&command, *data++) == 1) {
1614 int clen = *data++;
1615 len--;
1616 /* FIXME: this is properly an EA */
1617 clen >>= 1;
1618 /* Malformed command ? */
1619 if (clen > len)
1620 return;
1621 if (command & 1)
1622 gsm_control_message(dlci->gsm, command,
1623 data, clen);
1624 else
1625 gsm_control_response(dlci->gsm, command,
1626 data, clen);
1627 return;
1628 }
1629 }
1630}
1631
1632/*
1633 * Allocate/Free DLCI channels
1634 */
1635
1636/**
1637 * gsm_dlci_alloc - allocate a DLCI
1638 * @gsm: GSM mux
1639 * @addr: address of the DLCI
1640 *
1641 * Allocate and install a new DLCI object into the GSM mux.
1642 *
1643 * FIXME: review locking races
1644 */
1645
1646static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1647{
1648 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1649 if (dlci == NULL)
1650 return NULL;
1651 spin_lock_init(&dlci->lock);
1652 mutex_init(&dlci->mutex);
1653 if (kfifo_alloc(&dlci->fifo, 4096, GFP_KERNEL) < 0) {
1654 kfree(dlci);
1655 return NULL;
1656 }
1657
1658 skb_queue_head_init(&dlci->skb_list);
1659 timer_setup(&dlci->t1, gsm_dlci_t1, 0);
1660 tty_port_init(&dlci->port);
1661 dlci->port.ops = &gsm_port_ops;
1662 dlci->gsm = gsm;
1663 dlci->addr = addr;
1664 dlci->adaption = gsm->adaption;
1665 dlci->state = DLCI_CLOSED;
1666 if (addr)
1667 dlci->data = gsm_dlci_data;
1668 else
1669 dlci->data = gsm_dlci_command;
1670 gsm->dlci[addr] = dlci;
1671 return dlci;
1672}
1673
1674/**
1675 * gsm_dlci_free - free DLCI
1676 * @port: tty port for DLCI to free
1677 *
1678 * Free up a DLCI.
1679 *
1680 * Can sleep.
1681 */
1682static void gsm_dlci_free(struct tty_port *port)
1683{
1684 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
1685
1686 del_timer_sync(&dlci->t1);
1687 dlci->gsm->dlci[dlci->addr] = NULL;
1688 kfifo_free(&dlci->fifo);
1689 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1690 dev_kfree_skb(dlci->skb);
1691 kfree(dlci);
1692}
1693
1694static inline void dlci_get(struct gsm_dlci *dlci)
1695{
1696 tty_port_get(&dlci->port);
1697}
1698
1699static inline void dlci_put(struct gsm_dlci *dlci)
1700{
1701 tty_port_put(&dlci->port);
1702}
1703
1704static void gsm_destroy_network(struct gsm_dlci *dlci);
1705
1706/**
1707 * gsm_dlci_release - release DLCI
1708 * @dlci: DLCI to destroy
1709 *
1710 * Release a DLCI. Actual free is deferred until either
1711 * mux is closed or tty is closed - whichever is last.
1712 *
1713 * Can sleep.
1714 */
1715static void gsm_dlci_release(struct gsm_dlci *dlci)
1716{
1717 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1718 if (tty) {
1719 mutex_lock(&dlci->mutex);
1720 gsm_destroy_network(dlci);
1721 mutex_unlock(&dlci->mutex);
1722
1723 tty_hangup(tty);
1724
1725 tty_port_tty_set(&dlci->port, NULL);
1726 tty_kref_put(tty);
1727 }
1728 dlci->state = DLCI_CLOSED;
1729 dlci_put(dlci);
1730}
1731
1732/*
1733 * LAPBish link layer logic
1734 */
1735
1736/**
1737 * gsm_queue - a GSM frame is ready to process
1738 * @gsm: pointer to our gsm mux
1739 *
1740 * At this point in time a frame has arrived and been demangled from
1741 * the line encoding. All the differences between the encodings have
1742 * been handled below us and the frame is unpacked into the structures.
1743 * The fcs holds the header FCS but any data FCS must be added here.
1744 */
1745
1746static void gsm_queue(struct gsm_mux *gsm)
1747{
1748 struct gsm_dlci *dlci;
1749 u8 cr;
1750 int address;
1751 /* We have to sneak a look at the packet body to do the FCS.
1752 A somewhat layering violation in the spec */
1753
1754 if ((gsm->control & ~PF) == UI)
1755 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1756 if (gsm->encoding == 0) {
1757 /* WARNING: gsm->received_fcs is used for
1758 gsm->encoding = 0 only.
1759 In this case it contain the last piece of data
1760 required to generate final CRC */
1761 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1762 }
1763 if (gsm->fcs != GOOD_FCS) {
1764 gsm->bad_fcs++;
1765 if (debug & 4)
1766 pr_debug("BAD FCS %02x\n", gsm->fcs);
1767 return;
1768 }
1769 address = gsm->address >> 1;
1770 if (address >= NUM_DLCI)
1771 goto invalid;
1772
1773 cr = gsm->address & 1; /* C/R bit */
1774
1775 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1776
1777 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1778 dlci = gsm->dlci[address];
1779
1780 switch (gsm->control) {
1781 case SABM|PF:
1782 if (cr == 0)
1783 goto invalid;
1784 if (dlci == NULL)
1785 dlci = gsm_dlci_alloc(gsm, address);
1786 if (dlci == NULL)
1787 return;
1788 if (dlci->dead)
1789 gsm_response(gsm, address, DM);
1790 else {
1791 gsm_response(gsm, address, UA);
1792 gsm_dlci_open(dlci);
1793 }
1794 break;
1795 case DISC|PF:
1796 if (cr == 0)
1797 goto invalid;
1798 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1799 gsm_response(gsm, address, DM);
1800 return;
1801 }
1802 /* Real close complete */
1803 gsm_response(gsm, address, UA);
1804 gsm_dlci_close(dlci);
1805 break;
1806 case UA:
1807 case UA|PF:
1808 if (cr == 0 || dlci == NULL)
1809 break;
1810 switch (dlci->state) {
1811 case DLCI_CLOSING:
1812 gsm_dlci_close(dlci);
1813 break;
1814 case DLCI_OPENING:
1815 gsm_dlci_open(dlci);
1816 break;
1817 default:
1818 pr_debug("%s: unhandled state: %d\n", __func__,
1819 dlci->state);
1820 break;
1821 }
1822 break;
1823 case DM: /* DM can be valid unsolicited */
1824 case DM|PF:
1825 if (cr)
1826 goto invalid;
1827 if (dlci == NULL)
1828 return;
1829 gsm_dlci_close(dlci);
1830 break;
1831 case UI:
1832 case UI|PF:
1833 case UIH:
1834 case UIH|PF:
1835#if 0
1836 if (cr)
1837 goto invalid;
1838#endif
1839 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1840 gsm_command(gsm, address, DM|PF);
1841 return;
1842 }
1843 dlci->data(dlci, gsm->buf, gsm->len);
1844 break;
1845 default:
1846 goto invalid;
1847 }
1848 return;
1849invalid:
1850 gsm->malformed++;
1851 return;
1852}
1853
1854
1855/**
1856 * gsm0_receive - perform processing for non-transparency
1857 * @gsm: gsm data for this ldisc instance
1858 * @c: character
1859 *
1860 * Receive bytes in gsm mode 0
1861 */
1862
1863static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1864{
1865 unsigned int len;
1866
1867 switch (gsm->state) {
1868 case GSM_SEARCH: /* SOF marker */
1869 if (c == GSM0_SOF) {
1870 gsm->state = GSM_ADDRESS;
1871 gsm->address = 0;
1872 gsm->len = 0;
1873 gsm->fcs = INIT_FCS;
1874 }
1875 break;
1876 case GSM_ADDRESS: /* Address EA */
1877 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1878 if (gsm_read_ea(&gsm->address, c))
1879 gsm->state = GSM_CONTROL;
1880 break;
1881 case GSM_CONTROL: /* Control Byte */
1882 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1883 gsm->control = c;
1884 gsm->state = GSM_LEN0;
1885 break;
1886 case GSM_LEN0: /* Length EA */
1887 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1888 if (gsm_read_ea(&gsm->len, c)) {
1889 if (gsm->len > gsm->mru) {
1890 gsm->bad_size++;
1891 gsm->state = GSM_SEARCH;
1892 break;
1893 }
1894 gsm->count = 0;
1895 if (!gsm->len)
1896 gsm->state = GSM_FCS;
1897 else
1898 gsm->state = GSM_DATA;
1899 break;
1900 }
1901 gsm->state = GSM_LEN1;
1902 break;
1903 case GSM_LEN1:
1904 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1905 len = c;
1906 gsm->len |= len << 7;
1907 if (gsm->len > gsm->mru) {
1908 gsm->bad_size++;
1909 gsm->state = GSM_SEARCH;
1910 break;
1911 }
1912 gsm->count = 0;
1913 if (!gsm->len)
1914 gsm->state = GSM_FCS;
1915 else
1916 gsm->state = GSM_DATA;
1917 break;
1918 case GSM_DATA: /* Data */
1919 gsm->buf[gsm->count++] = c;
1920 if (gsm->count == gsm->len)
1921 gsm->state = GSM_FCS;
1922 break;
1923 case GSM_FCS: /* FCS follows the packet */
1924 gsm->received_fcs = c;
1925 gsm_queue(gsm);
1926 gsm->state = GSM_SSOF;
1927 break;
1928 case GSM_SSOF:
1929 if (c == GSM0_SOF) {
1930 gsm->state = GSM_SEARCH;
1931 break;
1932 }
1933 break;
1934 default:
1935 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
1936 break;
1937 }
1938}
1939
1940/**
1941 * gsm1_receive - perform processing for non-transparency
1942 * @gsm: gsm data for this ldisc instance
1943 * @c: character
1944 *
1945 * Receive bytes in mode 1 (Advanced option)
1946 */
1947
1948static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1949{
1950 if (c == GSM1_SOF) {
1951 /* EOF is only valid in frame if we have got to the data state
1952 and received at least one byte (the FCS) */
1953 if (gsm->state == GSM_DATA && gsm->count) {
1954 /* Extract the FCS */
1955 gsm->count--;
1956 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1957 gsm->len = gsm->count;
1958 gsm_queue(gsm);
1959 gsm->state = GSM_START;
1960 return;
1961 }
1962 /* Any partial frame was a runt so go back to start */
1963 if (gsm->state != GSM_START) {
1964 gsm->malformed++;
1965 gsm->state = GSM_START;
1966 }
1967 /* A SOF in GSM_START means we are still reading idling or
1968 framing bytes */
1969 return;
1970 }
1971
1972 if (c == GSM1_ESCAPE) {
1973 gsm->escape = true;
1974 return;
1975 }
1976
1977 /* Only an unescaped SOF gets us out of GSM search */
1978 if (gsm->state == GSM_SEARCH)
1979 return;
1980
1981 if (gsm->escape) {
1982 c ^= GSM1_ESCAPE_BITS;
1983 gsm->escape = false;
1984 }
1985 switch (gsm->state) {
1986 case GSM_START: /* First byte after SOF */
1987 gsm->address = 0;
1988 gsm->state = GSM_ADDRESS;
1989 gsm->fcs = INIT_FCS;
1990 fallthrough;
1991 case GSM_ADDRESS: /* Address continuation */
1992 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1993 if (gsm_read_ea(&gsm->address, c))
1994 gsm->state = GSM_CONTROL;
1995 break;
1996 case GSM_CONTROL: /* Control Byte */
1997 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1998 gsm->control = c;
1999 gsm->count = 0;
2000 gsm->state = GSM_DATA;
2001 break;
2002 case GSM_DATA: /* Data */
2003 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
2004 gsm->state = GSM_OVERRUN;
2005 gsm->bad_size++;
2006 } else
2007 gsm->buf[gsm->count++] = c;
2008 break;
2009 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
2010 break;
2011 default:
2012 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
2013 break;
2014 }
2015}
2016
2017/**
2018 * gsm_error - handle tty error
2019 * @gsm: ldisc data
2020 * @data: byte received (may be invalid)
2021 * @flag: error received
2022 *
2023 * Handle an error in the receipt of data for a frame. Currently we just
2024 * go back to hunting for a SOF.
2025 *
2026 * FIXME: better diagnostics ?
2027 */
2028
2029static void gsm_error(struct gsm_mux *gsm,
2030 unsigned char data, unsigned char flag)
2031{
2032 gsm->state = GSM_SEARCH;
2033 gsm->io_error++;
2034}
2035
2036static int gsm_disconnect(struct gsm_mux *gsm)
2037{
2038 struct gsm_dlci *dlci = gsm->dlci[0];
2039 struct gsm_control *gc;
2040
2041 if (!dlci)
2042 return 0;
2043
2044 /* In theory disconnecting DLCI 0 is sufficient but for some
2045 modems this is apparently not the case. */
2046 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2047 if (gc)
2048 gsm_control_wait(gsm, gc);
2049
2050 del_timer_sync(&gsm->t2_timer);
2051 /* Now we are sure T2 has stopped */
2052
2053 gsm_dlci_begin_close(dlci);
2054 wait_event_interruptible(gsm->event,
2055 dlci->state == DLCI_CLOSED);
2056
2057 if (signal_pending(current))
2058 return -EINTR;
2059
2060 return 0;
2061}
2062
2063/**
2064 * gsm_cleanup_mux - generic GSM protocol cleanup
2065 * @gsm: our mux
2066 *
2067 * Clean up the bits of the mux which are the same for all framing
2068 * protocols. Remove the mux from the mux table, stop all the timers
2069 * and then shut down each device hanging up the channels as we go.
2070 */
2071
2072static void gsm_cleanup_mux(struct gsm_mux *gsm)
2073{
2074 int i;
2075 struct gsm_dlci *dlci = gsm->dlci[0];
2076 struct gsm_msg *txq, *ntxq;
2077
2078 gsm->dead = true;
2079
2080 spin_lock(&gsm_mux_lock);
2081 for (i = 0; i < MAX_MUX; i++) {
2082 if (gsm_mux[i] == gsm) {
2083 gsm_mux[i] = NULL;
2084 break;
2085 }
2086 }
2087 spin_unlock(&gsm_mux_lock);
2088 /* open failed before registering => nothing to do */
2089 if (i == MAX_MUX)
2090 return;
2091
2092 del_timer_sync(&gsm->t2_timer);
2093 /* Now we are sure T2 has stopped */
2094 if (dlci)
2095 dlci->dead = true;
2096
2097 /* Free up any link layer users */
2098 mutex_lock(&gsm->mutex);
2099 for (i = 0; i < NUM_DLCI; i++)
2100 if (gsm->dlci[i])
2101 gsm_dlci_release(gsm->dlci[i]);
2102 mutex_unlock(&gsm->mutex);
2103 /* Now wipe the queues */
2104 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
2105 kfree(txq);
2106 INIT_LIST_HEAD(&gsm->tx_list);
2107}
2108
2109/**
2110 * gsm_activate_mux - generic GSM setup
2111 * @gsm: our mux
2112 *
2113 * Set up the bits of the mux which are the same for all framing
2114 * protocols. Add the mux to the mux table so it can be opened and
2115 * finally kick off connecting to DLCI 0 on the modem.
2116 */
2117
2118static int gsm_activate_mux(struct gsm_mux *gsm)
2119{
2120 struct gsm_dlci *dlci;
2121 int i = 0;
2122
2123 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
2124 init_waitqueue_head(&gsm->event);
2125 spin_lock_init(&gsm->control_lock);
2126 spin_lock_init(&gsm->tx_lock);
2127
2128 if (gsm->encoding == 0)
2129 gsm->receive = gsm0_receive;
2130 else
2131 gsm->receive = gsm1_receive;
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 * @gsm: 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 * @ref: kreference to the 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 ret = gsm_activate_mux(gsm);
2382 if (ret != 0)
2383 tty_kref_put(gsm->tty);
2384 else {
2385 /* Don't register device 0 - this is the control channel and not
2386 a usable tty interface */
2387 base = mux_num_to_base(gsm); /* Base for this MUX */
2388 for (i = 1; i < NUM_DLCI; i++) {
2389 struct device *dev;
2390
2391 dev = tty_register_device(gsm_tty_driver,
2392 base + i, NULL);
2393 if (IS_ERR(dev)) {
2394 for (i--; i >= 1; i--)
2395 tty_unregister_device(gsm_tty_driver,
2396 base + i);
2397 return PTR_ERR(dev);
2398 }
2399 }
2400 }
2401 return ret;
2402}
2403
2404
2405/**
2406 * gsmld_detach_gsm - stop doing 0710 mux
2407 * @tty: tty attached to the mux
2408 * @gsm: mux
2409 *
2410 * Shutdown and then clean up the resources used by the line discipline
2411 */
2412
2413static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2414{
2415 unsigned int base = mux_num_to_base(gsm); /* Base for this MUX */
2416 int i;
2417
2418 WARN_ON(tty != gsm->tty);
2419 for (i = 1; i < NUM_DLCI; i++)
2420 tty_unregister_device(gsm_tty_driver, base + i);
2421 gsm_cleanup_mux(gsm);
2422 tty_kref_put(gsm->tty);
2423 gsm->tty = NULL;
2424}
2425
2426static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2427 const char *fp, int count)
2428{
2429 struct gsm_mux *gsm = tty->disc_data;
2430 char flags = TTY_NORMAL;
2431
2432 if (debug & 4)
2433 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2434 cp, count);
2435
2436 for (; count; count--, cp++) {
2437 if (fp)
2438 flags = *fp++;
2439 switch (flags) {
2440 case TTY_NORMAL:
2441 gsm->receive(gsm, *cp);
2442 break;
2443 case TTY_OVERRUN:
2444 case TTY_BREAK:
2445 case TTY_PARITY:
2446 case TTY_FRAME:
2447 gsm_error(gsm, *cp, flags);
2448 break;
2449 default:
2450 WARN_ONCE(1, "%s: unknown flag %d\n",
2451 tty_name(tty), flags);
2452 break;
2453 }
2454 }
2455 /* FASYNC if needed ? */
2456 /* If clogged call tty_throttle(tty); */
2457}
2458
2459/**
2460 * gsmld_flush_buffer - clean input queue
2461 * @tty: terminal device
2462 *
2463 * Flush the input buffer. Called when the line discipline is
2464 * being closed, when the tty layer wants the buffer flushed (eg
2465 * at hangup).
2466 */
2467
2468static void gsmld_flush_buffer(struct tty_struct *tty)
2469{
2470}
2471
2472/**
2473 * gsmld_close - close the ldisc for this tty
2474 * @tty: device
2475 *
2476 * Called from the terminal layer when this line discipline is
2477 * being shut down, either because of a close or becsuse of a
2478 * discipline change. The function will not be called while other
2479 * ldisc methods are in progress.
2480 */
2481
2482static void gsmld_close(struct tty_struct *tty)
2483{
2484 struct gsm_mux *gsm = tty->disc_data;
2485
2486 gsmld_detach_gsm(tty, gsm);
2487
2488 gsmld_flush_buffer(tty);
2489 /* Do other clean up here */
2490 mux_put(gsm);
2491}
2492
2493/**
2494 * gsmld_open - open an ldisc
2495 * @tty: terminal to open
2496 *
2497 * Called when this line discipline is being attached to the
2498 * terminal device. Can sleep. Called serialized so that no
2499 * other events will occur in parallel. No further open will occur
2500 * until a close.
2501 */
2502
2503static int gsmld_open(struct tty_struct *tty)
2504{
2505 struct gsm_mux *gsm;
2506 int ret;
2507
2508 if (tty->ops->write == NULL)
2509 return -EINVAL;
2510
2511 /* Attach our ldisc data */
2512 gsm = gsm_alloc_mux();
2513 if (gsm == NULL)
2514 return -ENOMEM;
2515
2516 tty->disc_data = gsm;
2517 tty->receive_room = 65536;
2518
2519 /* Attach the initial passive connection */
2520 gsm->encoding = 1;
2521
2522 ret = gsmld_attach_gsm(tty, gsm);
2523 if (ret != 0) {
2524 gsm_cleanup_mux(gsm);
2525 mux_put(gsm);
2526 }
2527 return ret;
2528}
2529
2530/**
2531 * gsmld_write_wakeup - asynchronous I/O notifier
2532 * @tty: tty device
2533 *
2534 * Required for the ptys, serial driver etc. since processes
2535 * that attach themselves to the master and rely on ASYNC
2536 * IO must be woken up
2537 */
2538
2539static void gsmld_write_wakeup(struct tty_struct *tty)
2540{
2541 struct gsm_mux *gsm = tty->disc_data;
2542 unsigned long flags;
2543
2544 /* Queue poll */
2545 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2546 spin_lock_irqsave(&gsm->tx_lock, flags);
2547 gsm_data_kick(gsm, NULL);
2548 if (gsm->tx_bytes < TX_THRESH_LO) {
2549 gsm_dlci_data_sweep(gsm);
2550 }
2551 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2552}
2553
2554/**
2555 * gsmld_read - read function for tty
2556 * @tty: tty device
2557 * @file: file object
2558 * @buf: userspace buffer pointer
2559 * @nr: size of I/O
2560 * @cookie: unused
2561 * @offset: unused
2562 *
2563 * Perform reads for the line discipline. We are guaranteed that the
2564 * line discipline will not be closed under us but we may get multiple
2565 * parallel readers and must handle this ourselves. We may also get
2566 * a hangup. Always called in user context, may sleep.
2567 *
2568 * This code must be sure never to sleep through a hangup.
2569 */
2570
2571static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2572 unsigned char *buf, size_t nr,
2573 void **cookie, unsigned long offset)
2574{
2575 return -EOPNOTSUPP;
2576}
2577
2578/**
2579 * gsmld_write - write function for tty
2580 * @tty: tty device
2581 * @file: file object
2582 * @buf: userspace buffer pointer
2583 * @nr: size of I/O
2584 *
2585 * Called when the owner of the device wants to send a frame
2586 * itself (or some other control data). The data is transferred
2587 * as-is and must be properly framed and checksummed as appropriate
2588 * by userspace. Frames are either sent whole or not at all as this
2589 * avoids pain user side.
2590 */
2591
2592static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2593 const unsigned char *buf, size_t nr)
2594{
2595 int space = tty_write_room(tty);
2596 if (space >= nr)
2597 return tty->ops->write(tty, buf, nr);
2598 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2599 return -ENOBUFS;
2600}
2601
2602/**
2603 * gsmld_poll - poll method for N_GSM0710
2604 * @tty: terminal device
2605 * @file: file accessing it
2606 * @wait: poll table
2607 *
2608 * Called when the line discipline is asked to poll() for data or
2609 * for special events. This code is not serialized with respect to
2610 * other events save open/close.
2611 *
2612 * This code must be sure never to sleep through a hangup.
2613 * Called without the kernel lock held - fine
2614 */
2615
2616static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
2617 poll_table *wait)
2618{
2619 __poll_t mask = 0;
2620 struct gsm_mux *gsm = tty->disc_data;
2621
2622 poll_wait(file, &tty->read_wait, wait);
2623 poll_wait(file, &tty->write_wait, wait);
2624 if (tty_hung_up_p(file))
2625 mask |= EPOLLHUP;
2626 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2627 mask |= EPOLLOUT | EPOLLWRNORM;
2628 if (gsm->dead)
2629 mask |= EPOLLHUP;
2630 return mask;
2631}
2632
2633static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2634 unsigned int cmd, unsigned long arg)
2635{
2636 struct gsm_config c;
2637 struct gsm_mux *gsm = tty->disc_data;
2638 unsigned int base;
2639
2640 switch (cmd) {
2641 case GSMIOC_GETCONF:
2642 gsm_copy_config_values(gsm, &c);
2643 if (copy_to_user((void __user *)arg, &c, sizeof(c)))
2644 return -EFAULT;
2645 return 0;
2646 case GSMIOC_SETCONF:
2647 if (copy_from_user(&c, (void __user *)arg, sizeof(c)))
2648 return -EFAULT;
2649 return gsm_config(gsm, &c);
2650 case GSMIOC_GETFIRST:
2651 base = mux_num_to_base(gsm);
2652 return put_user(base + 1, (__u32 __user *)arg);
2653 default:
2654 return n_tty_ioctl_helper(tty, file, cmd, arg);
2655 }
2656}
2657
2658/*
2659 * Network interface
2660 *
2661 */
2662
2663static int gsm_mux_net_open(struct net_device *net)
2664{
2665 pr_debug("%s called\n", __func__);
2666 netif_start_queue(net);
2667 return 0;
2668}
2669
2670static int gsm_mux_net_close(struct net_device *net)
2671{
2672 netif_stop_queue(net);
2673 return 0;
2674}
2675
2676static void dlci_net_free(struct gsm_dlci *dlci)
2677{
2678 if (!dlci->net) {
2679 WARN_ON(1);
2680 return;
2681 }
2682 dlci->adaption = dlci->prev_adaption;
2683 dlci->data = dlci->prev_data;
2684 free_netdev(dlci->net);
2685 dlci->net = NULL;
2686}
2687static void net_free(struct kref *ref)
2688{
2689 struct gsm_mux_net *mux_net;
2690 struct gsm_dlci *dlci;
2691
2692 mux_net = container_of(ref, struct gsm_mux_net, ref);
2693 dlci = mux_net->dlci;
2694
2695 if (dlci->net) {
2696 unregister_netdev(dlci->net);
2697 dlci_net_free(dlci);
2698 }
2699}
2700
2701static inline void muxnet_get(struct gsm_mux_net *mux_net)
2702{
2703 kref_get(&mux_net->ref);
2704}
2705
2706static inline void muxnet_put(struct gsm_mux_net *mux_net)
2707{
2708 kref_put(&mux_net->ref, net_free);
2709}
2710
2711static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
2712 struct net_device *net)
2713{
2714 struct gsm_mux_net *mux_net = netdev_priv(net);
2715 struct gsm_dlci *dlci = mux_net->dlci;
2716 muxnet_get(mux_net);
2717
2718 skb_queue_head(&dlci->skb_list, skb);
2719 net->stats.tx_packets++;
2720 net->stats.tx_bytes += skb->len;
2721 gsm_dlci_data_kick(dlci);
2722 /* And tell the kernel when the last transmit started. */
2723 netif_trans_update(net);
2724 muxnet_put(mux_net);
2725 return NETDEV_TX_OK;
2726}
2727
2728/* called when a packet did not ack after watchdogtimeout */
2729static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue)
2730{
2731 /* Tell syslog we are hosed. */
2732 dev_dbg(&net->dev, "Tx timed out.\n");
2733
2734 /* Update statistics */
2735 net->stats.tx_errors++;
2736}
2737
2738static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2739 const unsigned char *in_buf, int size)
2740{
2741 struct net_device *net = dlci->net;
2742 struct sk_buff *skb;
2743 struct gsm_mux_net *mux_net = netdev_priv(net);
2744 muxnet_get(mux_net);
2745
2746 /* Allocate an sk_buff */
2747 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2748 if (!skb) {
2749 /* We got no receive buffer. */
2750 net->stats.rx_dropped++;
2751 muxnet_put(mux_net);
2752 return;
2753 }
2754 skb_reserve(skb, NET_IP_ALIGN);
2755 skb_put_data(skb, in_buf, size);
2756
2757 skb->dev = net;
2758 skb->protocol = htons(ETH_P_IP);
2759
2760 /* Ship it off to the kernel */
2761 netif_rx(skb);
2762
2763 /* update out statistics */
2764 net->stats.rx_packets++;
2765 net->stats.rx_bytes += size;
2766 muxnet_put(mux_net);
2767 return;
2768}
2769
2770static void gsm_mux_net_init(struct net_device *net)
2771{
2772 static const struct net_device_ops gsm_netdev_ops = {
2773 .ndo_open = gsm_mux_net_open,
2774 .ndo_stop = gsm_mux_net_close,
2775 .ndo_start_xmit = gsm_mux_net_start_xmit,
2776 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2777 };
2778
2779 net->netdev_ops = &gsm_netdev_ops;
2780
2781 /* fill in the other fields */
2782 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2783 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2784 net->type = ARPHRD_NONE;
2785 net->tx_queue_len = 10;
2786}
2787
2788
2789/* caller holds the dlci mutex */
2790static void gsm_destroy_network(struct gsm_dlci *dlci)
2791{
2792 struct gsm_mux_net *mux_net;
2793
2794 pr_debug("destroy network interface\n");
2795 if (!dlci->net)
2796 return;
2797 mux_net = netdev_priv(dlci->net);
2798 muxnet_put(mux_net);
2799}
2800
2801
2802/* caller holds the dlci mutex */
2803static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2804{
2805 char *netname;
2806 int retval = 0;
2807 struct net_device *net;
2808 struct gsm_mux_net *mux_net;
2809
2810 if (!capable(CAP_NET_ADMIN))
2811 return -EPERM;
2812
2813 /* Already in a non tty mode */
2814 if (dlci->adaption > 2)
2815 return -EBUSY;
2816
2817 if (nc->protocol != htons(ETH_P_IP))
2818 return -EPROTONOSUPPORT;
2819
2820 if (nc->adaption != 3 && nc->adaption != 4)
2821 return -EPROTONOSUPPORT;
2822
2823 pr_debug("create network interface\n");
2824
2825 netname = "gsm%d";
2826 if (nc->if_name[0] != '\0')
2827 netname = nc->if_name;
2828 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
2829 NET_NAME_UNKNOWN, gsm_mux_net_init);
2830 if (!net) {
2831 pr_err("alloc_netdev failed\n");
2832 return -ENOMEM;
2833 }
2834 net->mtu = dlci->gsm->mtu;
2835 net->min_mtu = 8;
2836 net->max_mtu = dlci->gsm->mtu;
2837 mux_net = netdev_priv(net);
2838 mux_net->dlci = dlci;
2839 kref_init(&mux_net->ref);
2840 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2841
2842 /* reconfigure dlci for network */
2843 dlci->prev_adaption = dlci->adaption;
2844 dlci->prev_data = dlci->data;
2845 dlci->adaption = nc->adaption;
2846 dlci->data = gsm_mux_rx_netchar;
2847 dlci->net = net;
2848
2849 pr_debug("register netdev\n");
2850 retval = register_netdev(net);
2851 if (retval) {
2852 pr_err("network register fail %d\n", retval);
2853 dlci_net_free(dlci);
2854 return retval;
2855 }
2856 return net->ifindex; /* return network index */
2857}
2858
2859/* Line discipline for real tty */
2860static struct tty_ldisc_ops tty_ldisc_packet = {
2861 .owner = THIS_MODULE,
2862 .num = N_GSM0710,
2863 .name = "n_gsm",
2864 .open = gsmld_open,
2865 .close = gsmld_close,
2866 .flush_buffer = gsmld_flush_buffer,
2867 .read = gsmld_read,
2868 .write = gsmld_write,
2869 .ioctl = gsmld_ioctl,
2870 .poll = gsmld_poll,
2871 .receive_buf = gsmld_receive_buf,
2872 .write_wakeup = gsmld_write_wakeup
2873};
2874
2875/*
2876 * Virtual tty side
2877 */
2878
2879#define TX_SIZE 512
2880
2881static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2882{
2883 u8 modembits[5];
2884 struct gsm_control *ctrl;
2885 int len = 2;
2886
2887 if (brk)
2888 len++;
2889
2890 modembits[0] = len << 1 | EA; /* Data bytes */
2891 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2892 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2893 if (brk)
2894 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2895 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2896 if (ctrl == NULL)
2897 return -ENOMEM;
2898 return gsm_control_wait(dlci->gsm, ctrl);
2899}
2900
2901static int gsm_carrier_raised(struct tty_port *port)
2902{
2903 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2904 struct gsm_mux *gsm = dlci->gsm;
2905
2906 /* Not yet open so no carrier info */
2907 if (dlci->state != DLCI_OPEN)
2908 return 0;
2909 if (debug & 2)
2910 return 1;
2911
2912 /*
2913 * Basic mode with control channel in ADM mode may not respond
2914 * to CMD_MSC at all and modem_rx is empty.
2915 */
2916 if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM &&
2917 !dlci->modem_rx)
2918 return 1;
2919
2920 return dlci->modem_rx & TIOCM_CD;
2921}
2922
2923static void gsm_dtr_rts(struct tty_port *port, int onoff)
2924{
2925 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2926 unsigned int modem_tx = dlci->modem_tx;
2927 if (onoff)
2928 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2929 else
2930 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2931 if (modem_tx != dlci->modem_tx) {
2932 dlci->modem_tx = modem_tx;
2933 gsmtty_modem_update(dlci, 0);
2934 }
2935}
2936
2937static const struct tty_port_operations gsm_port_ops = {
2938 .carrier_raised = gsm_carrier_raised,
2939 .dtr_rts = gsm_dtr_rts,
2940 .destruct = gsm_dlci_free,
2941};
2942
2943static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
2944{
2945 struct gsm_mux *gsm;
2946 struct gsm_dlci *dlci;
2947 unsigned int line = tty->index;
2948 unsigned int mux = mux_line_to_num(line);
2949 bool alloc = false;
2950 int ret;
2951
2952 line = line & 0x3F;
2953
2954 if (mux >= MAX_MUX)
2955 return -ENXIO;
2956 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2957 if (gsm_mux[mux] == NULL)
2958 return -EUNATCH;
2959 if (line == 0 || line > 61) /* 62/63 reserved */
2960 return -ECHRNG;
2961 gsm = gsm_mux[mux];
2962 if (gsm->dead)
2963 return -EL2HLT;
2964 /* If DLCI 0 is not yet fully open return an error.
2965 This is ok from a locking
2966 perspective as we don't have to worry about this
2967 if DLCI0 is lost */
2968 mutex_lock(&gsm->mutex);
2969 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
2970 mutex_unlock(&gsm->mutex);
2971 return -EL2NSYNC;
2972 }
2973 dlci = gsm->dlci[line];
2974 if (dlci == NULL) {
2975 alloc = true;
2976 dlci = gsm_dlci_alloc(gsm, line);
2977 }
2978 if (dlci == NULL) {
2979 mutex_unlock(&gsm->mutex);
2980 return -ENOMEM;
2981 }
2982 ret = tty_port_install(&dlci->port, driver, tty);
2983 if (ret) {
2984 if (alloc)
2985 dlci_put(dlci);
2986 mutex_unlock(&gsm->mutex);
2987 return ret;
2988 }
2989
2990 dlci_get(dlci);
2991 dlci_get(gsm->dlci[0]);
2992 mux_get(gsm);
2993 tty->driver_data = dlci;
2994 mutex_unlock(&gsm->mutex);
2995
2996 return 0;
2997}
2998
2999static int gsmtty_open(struct tty_struct *tty, struct file *filp)
3000{
3001 struct gsm_dlci *dlci = tty->driver_data;
3002 struct tty_port *port = &dlci->port;
3003
3004 port->count++;
3005 tty_port_tty_set(port, tty);
3006
3007 dlci->modem_rx = 0;
3008 /* We could in theory open and close before we wait - eg if we get
3009 a DM straight back. This is ok as that will have caused a hangup */
3010 tty_port_set_initialized(port, 1);
3011 /* Start sending off SABM messages */
3012 gsm_dlci_begin_open(dlci);
3013 /* And wait for virtual carrier */
3014 return tty_port_block_til_ready(port, tty, filp);
3015}
3016
3017static void gsmtty_close(struct tty_struct *tty, struct file *filp)
3018{
3019 struct gsm_dlci *dlci = tty->driver_data;
3020
3021 if (dlci == NULL)
3022 return;
3023 if (dlci->state == DLCI_CLOSED)
3024 return;
3025 mutex_lock(&dlci->mutex);
3026 gsm_destroy_network(dlci);
3027 mutex_unlock(&dlci->mutex);
3028 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
3029 return;
3030 gsm_dlci_begin_close(dlci);
3031 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
3032 tty_port_lower_dtr_rts(&dlci->port);
3033 tty_port_close_end(&dlci->port, tty);
3034 tty_port_tty_set(&dlci->port, NULL);
3035 return;
3036}
3037
3038static void gsmtty_hangup(struct tty_struct *tty)
3039{
3040 struct gsm_dlci *dlci = tty->driver_data;
3041 if (dlci->state == DLCI_CLOSED)
3042 return;
3043 tty_port_hangup(&dlci->port);
3044 gsm_dlci_begin_close(dlci);
3045}
3046
3047static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3048 int len)
3049{
3050 int sent;
3051 struct gsm_dlci *dlci = tty->driver_data;
3052 if (dlci->state == DLCI_CLOSED)
3053 return -EINVAL;
3054 /* Stuff the bytes into the fifo queue */
3055 sent = kfifo_in_locked(&dlci->fifo, buf, len, &dlci->lock);
3056 /* Need to kick the channel */
3057 gsm_dlci_data_kick(dlci);
3058 return sent;
3059}
3060
3061static unsigned int gsmtty_write_room(struct tty_struct *tty)
3062{
3063 struct gsm_dlci *dlci = tty->driver_data;
3064 if (dlci->state == DLCI_CLOSED)
3065 return 0;
3066 return TX_SIZE - kfifo_len(&dlci->fifo);
3067}
3068
3069static unsigned int gsmtty_chars_in_buffer(struct tty_struct *tty)
3070{
3071 struct gsm_dlci *dlci = tty->driver_data;
3072 if (dlci->state == DLCI_CLOSED)
3073 return 0;
3074 return kfifo_len(&dlci->fifo);
3075}
3076
3077static void gsmtty_flush_buffer(struct tty_struct *tty)
3078{
3079 struct gsm_dlci *dlci = tty->driver_data;
3080 if (dlci->state == DLCI_CLOSED)
3081 return;
3082 /* Caution needed: If we implement reliable transport classes
3083 then the data being transmitted can't simply be junked once
3084 it has first hit the stack. Until then we can just blow it
3085 away */
3086 kfifo_reset(&dlci->fifo);
3087 /* Need to unhook this DLCI from the transmit queue logic */
3088}
3089
3090static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3091{
3092 /* The FIFO handles the queue so the kernel will do the right
3093 thing waiting on chars_in_buffer before calling us. No work
3094 to do here */
3095}
3096
3097static int gsmtty_tiocmget(struct tty_struct *tty)
3098{
3099 struct gsm_dlci *dlci = tty->driver_data;
3100 if (dlci->state == DLCI_CLOSED)
3101 return -EINVAL;
3102 return dlci->modem_rx;
3103}
3104
3105static int gsmtty_tiocmset(struct tty_struct *tty,
3106 unsigned int set, unsigned int clear)
3107{
3108 struct gsm_dlci *dlci = tty->driver_data;
3109 unsigned int modem_tx = dlci->modem_tx;
3110
3111 if (dlci->state == DLCI_CLOSED)
3112 return -EINVAL;
3113 modem_tx &= ~clear;
3114 modem_tx |= set;
3115
3116 if (modem_tx != dlci->modem_tx) {
3117 dlci->modem_tx = modem_tx;
3118 return gsmtty_modem_update(dlci, 0);
3119 }
3120 return 0;
3121}
3122
3123
3124static int gsmtty_ioctl(struct tty_struct *tty,
3125 unsigned int cmd, unsigned long arg)
3126{
3127 struct gsm_dlci *dlci = tty->driver_data;
3128 struct gsm_netconfig nc;
3129 int index;
3130
3131 if (dlci->state == DLCI_CLOSED)
3132 return -EINVAL;
3133 switch (cmd) {
3134 case GSMIOC_ENABLE_NET:
3135 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3136 return -EFAULT;
3137 nc.if_name[IFNAMSIZ-1] = '\0';
3138 /* return net interface index or error code */
3139 mutex_lock(&dlci->mutex);
3140 index = gsm_create_network(dlci, &nc);
3141 mutex_unlock(&dlci->mutex);
3142 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3143 return -EFAULT;
3144 return index;
3145 case GSMIOC_DISABLE_NET:
3146 if (!capable(CAP_NET_ADMIN))
3147 return -EPERM;
3148 mutex_lock(&dlci->mutex);
3149 gsm_destroy_network(dlci);
3150 mutex_unlock(&dlci->mutex);
3151 return 0;
3152 default:
3153 return -ENOIOCTLCMD;
3154 }
3155}
3156
3157static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3158{
3159 struct gsm_dlci *dlci = tty->driver_data;
3160 if (dlci->state == DLCI_CLOSED)
3161 return;
3162 /* For the moment its fixed. In actual fact the speed information
3163 for the virtual channel can be propogated in both directions by
3164 the RPN control message. This however rapidly gets nasty as we
3165 then have to remap modem signals each way according to whether
3166 our virtual cable is null modem etc .. */
3167 tty_termios_copy_hw(&tty->termios, old);
3168}
3169
3170static void gsmtty_throttle(struct tty_struct *tty)
3171{
3172 struct gsm_dlci *dlci = tty->driver_data;
3173 if (dlci->state == DLCI_CLOSED)
3174 return;
3175 if (C_CRTSCTS(tty))
3176 dlci->modem_tx &= ~TIOCM_DTR;
3177 dlci->throttled = true;
3178 /* Send an MSC with DTR cleared */
3179 gsmtty_modem_update(dlci, 0);
3180}
3181
3182static void gsmtty_unthrottle(struct tty_struct *tty)
3183{
3184 struct gsm_dlci *dlci = tty->driver_data;
3185 if (dlci->state == DLCI_CLOSED)
3186 return;
3187 if (C_CRTSCTS(tty))
3188 dlci->modem_tx |= TIOCM_DTR;
3189 dlci->throttled = false;
3190 /* Send an MSC with DTR set */
3191 gsmtty_modem_update(dlci, 0);
3192}
3193
3194static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3195{
3196 struct gsm_dlci *dlci = tty->driver_data;
3197 int encode = 0; /* Off */
3198 if (dlci->state == DLCI_CLOSED)
3199 return -EINVAL;
3200
3201 if (state == -1) /* "On indefinitely" - we can't encode this
3202 properly */
3203 encode = 0x0F;
3204 else if (state > 0) {
3205 encode = state / 200; /* mS to encoding */
3206 if (encode > 0x0F)
3207 encode = 0x0F; /* Best effort */
3208 }
3209 return gsmtty_modem_update(dlci, encode);
3210}
3211
3212static void gsmtty_cleanup(struct tty_struct *tty)
3213{
3214 struct gsm_dlci *dlci = tty->driver_data;
3215 struct gsm_mux *gsm = dlci->gsm;
3216
3217 dlci_put(dlci);
3218 dlci_put(gsm->dlci[0]);
3219 mux_put(gsm);
3220}
3221
3222/* Virtual ttys for the demux */
3223static const struct tty_operations gsmtty_ops = {
3224 .install = gsmtty_install,
3225 .open = gsmtty_open,
3226 .close = gsmtty_close,
3227 .write = gsmtty_write,
3228 .write_room = gsmtty_write_room,
3229 .chars_in_buffer = gsmtty_chars_in_buffer,
3230 .flush_buffer = gsmtty_flush_buffer,
3231 .ioctl = gsmtty_ioctl,
3232 .throttle = gsmtty_throttle,
3233 .unthrottle = gsmtty_unthrottle,
3234 .set_termios = gsmtty_set_termios,
3235 .hangup = gsmtty_hangup,
3236 .wait_until_sent = gsmtty_wait_until_sent,
3237 .tiocmget = gsmtty_tiocmget,
3238 .tiocmset = gsmtty_tiocmset,
3239 .break_ctl = gsmtty_break_ctl,
3240 .cleanup = gsmtty_cleanup,
3241};
3242
3243
3244
3245static int __init gsm_init(void)
3246{
3247 /* Fill in our line protocol discipline, and register it */
3248 int status = tty_register_ldisc(&tty_ldisc_packet);
3249 if (status != 0) {
3250 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3251 status);
3252 return status;
3253 }
3254
3255 gsm_tty_driver = alloc_tty_driver(256);
3256 if (!gsm_tty_driver) {
3257 pr_err("gsm_init: tty allocation failed.\n");
3258 status = -ENOMEM;
3259 goto err_unreg_ldisc;
3260 }
3261 gsm_tty_driver->driver_name = "gsmtty";
3262 gsm_tty_driver->name = "gsmtty";
3263 gsm_tty_driver->major = 0; /* Dynamic */
3264 gsm_tty_driver->minor_start = 0;
3265 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3266 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3267 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3268 | TTY_DRIVER_HARDWARE_BREAK;
3269 gsm_tty_driver->init_termios = tty_std_termios;
3270 /* Fixme */
3271 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3272 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3273
3274 if (tty_register_driver(gsm_tty_driver)) {
3275 pr_err("gsm_init: tty registration failed.\n");
3276 status = -EBUSY;
3277 goto err_put_driver;
3278 }
3279 pr_debug("gsm_init: loaded as %d,%d.\n",
3280 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3281 return 0;
3282err_put_driver:
3283 put_tty_driver(gsm_tty_driver);
3284err_unreg_ldisc:
3285 tty_unregister_ldisc(&tty_ldisc_packet);
3286 return status;
3287}
3288
3289static void __exit gsm_exit(void)
3290{
3291 tty_unregister_ldisc(&tty_ldisc_packet);
3292 tty_unregister_driver(gsm_tty_driver);
3293 put_tty_driver(gsm_tty_driver);
3294}
3295
3296module_init(gsm_init);
3297module_exit(gsm_exit);
3298
3299
3300MODULE_LICENSE("GPL");
3301MODULE_ALIAS_LDISC(N_GSM0710);