projects/linux·blob master · refs

4659 lines · 113.7 KiB

1// SPDX-License-Identifier: GPL-2.0
2/*
3 * n_gsm.c GSM 0710 tty multiplexor
4 * Copyright (c) 2009/10 Intel Corporation
5 * Copyright (c) 2022/23 Siemens Mobility GmbH
6 *
7 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
8 *
9 * Outgoing path:
10 * tty -> DLCI fifo -> scheduler -> GSM MUX data queue ---o-> ldisc
11 * control message -> GSM MUX control queue --´
12 *
13 * Incoming path:
14 * ldisc -> gsm_queue() -o--> tty
15 * `-> gsm_control_response()
16 *
17 * TO DO:
18 * Mostly done: ioctls for setting modes/timing
19 * Partly done: hooks so you can pull off frames to non tty devs
20 * Restart DLCI 0 when it closes ?
21 * Improve the tx engine
22 * Resolve tx side locking by adding a queue_head and routing
23 * all control traffic via it
24 * General tidy/document
25 * Review the locking/move to refcounts more (mux now moved to an
26 * alloc/free model ready)
27 * Use newest tty open/close port helpers and install hooks
28 * What to do about power functions ?
29 * Termios setting and negotiation
30 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
31 *
32 */
33
34#include <linux/types.h>
35#include <linux/major.h>
36#include <linux/errno.h>
37#include <linux/signal.h>
38#include <linux/fcntl.h>
39#include <linux/sched/signal.h>
40#include <linux/interrupt.h>
41#include <linux/tty.h>
42#include <linux/bitfield.h>
43#include <linux/ctype.h>
44#include <linux/mm.h>
45#include <linux/math.h>
46#include <linux/nospec.h>
47#include <linux/string.h>
48#include <linux/slab.h>
49#include <linux/poll.h>
50#include <linux/bitops.h>
51#include <linux/file.h>
52#include <linux/uaccess.h>
53#include <linux/module.h>
54#include <linux/timer.h>
55#include <linux/tty_flip.h>
56#include <linux/tty_driver.h>
57#include <linux/serial.h>
58#include <linux/kfifo.h>
59#include <linux/skbuff.h>
60#include <net/arp.h>
61#include <linux/ip.h>
62#include <linux/netdevice.h>
63#include <linux/etherdevice.h>
64#include <linux/gsmmux.h>
65#include "tty.h"
66
67static int debug;
68module_param(debug, int, 0600);
69
70/* Module debug bits */
71#define DBG_DUMP BIT(0) /* Data transmission dump. */
72#define DBG_CD_ON BIT(1) /* Always assume CD line on. */
73#define DBG_DATA BIT(2) /* Data transmission details. */
74#define DBG_ERRORS BIT(3) /* Details for fail conditions. */
75#define DBG_TTY BIT(4) /* Transmission statistics for DLCI TTYs. */
76#define DBG_PAYLOAD BIT(5) /* Limits DBG_DUMP to payload frames. */
77
78/* Defaults: these are from the specification */
79
80#define T1 10 /* 100mS */
81#define T2 34 /* 333mS */
82#define T3 10 /* 10s */
83#define N2 3 /* Retry 3 times */
84#define K 2 /* outstanding I frames */
85
86#define MAX_T3 255 /* In seconds. */
87#define MAX_WINDOW_SIZE 7 /* Limit of K in error recovery mode. */
88
89/* Use long timers for testing at low speed with debug on */
90#ifdef DEBUG_TIMING
91#define T1 100
92#define T2 200
93#endif
94
95/*
96 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
97 * limits so this is plenty
98 */
99#define MAX_MRU 1500
100#define MAX_MTU 1500
101#define MIN_MTU (PROT_OVERHEAD + 1)
102/* SOF, ADDR, CTRL, LEN1, LEN2, ..., FCS, EOF */
103#define PROT_OVERHEAD 7
104#define GSM_NET_TX_TIMEOUT (HZ*10)
105
106/*
107 * struct gsm_mux_net - network interface
108 *
109 * Created when net interface is initialized.
110 */
111struct gsm_mux_net {
112 struct kref ref;
113 struct gsm_dlci *dlci;
114};
115
116/*
117 * Each block of data we have queued to go out is in the form of
118 * a gsm_msg which holds everything we need in a link layer independent
119 * format
120 */
121
122struct gsm_msg {
123 struct list_head list;
124 u8 addr; /* DLCI address + flags */
125 u8 ctrl; /* Control byte + flags */
126 unsigned int len; /* Length of data block (can be zero) */
127 u8 *data; /* Points into buffer but not at the start */
128 u8 buffer[];
129};
130
131enum gsm_dlci_state {
132 DLCI_CLOSED,
133 DLCI_WAITING_CONFIG, /* Waiting for DLCI configuration from user */
134 DLCI_CONFIGURE, /* Sending PN (for adaption > 1) */
135 DLCI_OPENING, /* Sending SABM not seen UA */
136 DLCI_OPEN, /* SABM/UA complete */
137 DLCI_CLOSING, /* Sending DISC not seen UA/DM */
138};
139
140enum gsm_dlci_mode {
141 DLCI_MODE_ABM, /* Normal Asynchronous Balanced Mode */
142 DLCI_MODE_ADM, /* Asynchronous Disconnected Mode */
143};
144
145/*
146 * Each active data link has a gsm_dlci structure associated which ties
147 * the link layer to an optional tty (if the tty side is open). To avoid
148 * complexity right now these are only ever freed up when the mux is
149 * shut down.
150 *
151 * At the moment we don't free DLCI objects until the mux is torn down
152 * this avoid object life time issues but might be worth review later.
153 */
154
155struct gsm_dlci {
156 struct gsm_mux *gsm;
157 int addr;
158 enum gsm_dlci_state state;
159 struct mutex mutex;
160
161 /* Link layer */
162 enum gsm_dlci_mode mode;
163 spinlock_t lock; /* Protects the internal state */
164 struct timer_list t1; /* Retransmit timer for SABM and UA */
165 int retries;
166 /* Uplink tty if active */
167 struct tty_port port; /* The tty bound to this DLCI if there is one */
168#define TX_SIZE 4096 /* Must be power of 2. */
169 struct kfifo fifo; /* Queue fifo for the DLCI */
170 int adaption; /* Adaption layer in use */
171 int prev_adaption;
172 u32 modem_rx; /* Our incoming virtual modem lines */
173 u32 modem_tx; /* Our outgoing modem lines */
174 unsigned int mtu;
175 bool dead; /* Refuse re-open */
176 /* Configuration */
177 u8 prio; /* Priority */
178 u8 ftype; /* Frame type */
179 u8 k; /* Window size */
180 /* Flow control */
181 bool throttled; /* Private copy of throttle state */
182 bool constipated; /* Throttle status for outgoing */
183 /* Packetised I/O */
184 struct sk_buff *skb; /* Frame being sent */
185 struct sk_buff_head skb_list; /* Queued frames */
186 /* Data handling callback */
187 void (*data)(struct gsm_dlci *dlci, const u8 *data, int len);
188 void (*prev_data)(struct gsm_dlci *dlci, const u8 *data, int len);
189 struct net_device *net; /* network interface, if created */
190};
191
192/*
193 * Parameter bits used for parameter negotiation according to 3GPP 27.010
194 * chapter 5.4.6.3.1.
195 */
196
197struct gsm_dlci_param_bits {
198 u8 d_bits;
199 u8 i_cl_bits;
200 u8 p_bits;
201 u8 t_bits;
202 __le16 n_bits;
203 u8 na_bits;
204 u8 k_bits;
205};
206
207static_assert(sizeof(struct gsm_dlci_param_bits) == 8);
208
209#define PN_D_FIELD_DLCI GENMASK(5, 0)
210#define PN_I_CL_FIELD_FTYPE GENMASK(3, 0)
211#define PN_I_CL_FIELD_ADAPTION GENMASK(7, 4)
212#define PN_P_FIELD_PRIO GENMASK(5, 0)
213#define PN_T_FIELD_T1 GENMASK(7, 0)
214#define PN_N_FIELD_N1 GENMASK(15, 0)
215#define PN_NA_FIELD_N2 GENMASK(7, 0)
216#define PN_K_FIELD_K GENMASK(2, 0)
217
218/* Total number of supported devices */
219#define GSM_TTY_MINORS 256
220
221/* DLCI 0, 62/63 are special or reserved see gsmtty_open */
222
223#define NUM_DLCI 64
224
225/*
226 * DLCI 0 is used to pass control blocks out of band of the data
227 * flow (and with a higher link priority). One command can be outstanding
228 * at a time and we use this structure to manage them. They are created
229 * and destroyed by the user context, and updated by the receive paths
230 * and timers
231 */
232
233struct gsm_control {
234 u8 cmd; /* Command we are issuing */
235 u8 *data; /* Data for the command in case we retransmit */
236 int len; /* Length of block for retransmission */
237 int done; /* Done flag */
238 int error; /* Error if any */
239};
240
241enum gsm_encoding {
242 GSM_BASIC_OPT,
243 GSM_ADV_OPT,
244};
245
246enum gsm_mux_state {
247 GSM_SEARCH,
248 GSM0_ADDRESS,
249 GSM0_CONTROL,
250 GSM0_LEN0,
251 GSM0_LEN1,
252 GSM0_DATA,
253 GSM0_FCS,
254 GSM0_SSOF,
255 GSM1_START,
256 GSM1_ADDRESS,
257 GSM1_CONTROL,
258 GSM1_DATA,
259 GSM1_OVERRUN,
260};
261
262/*
263 * Each GSM mux we have is represented by this structure. If we are
264 * operating as an ldisc then we use this structure as our ldisc
265 * state. We need to sort out lifetimes and locking with respect
266 * to the gsm mux array. For now we don't free DLCI objects that
267 * have been instantiated until the mux itself is terminated.
268 *
269 * To consider further: tty open versus mux shutdown.
270 */
271
272struct gsm_mux {
273 struct tty_struct *tty; /* The tty our ldisc is bound to */
274 spinlock_t lock;
275 struct mutex mutex;
276 unsigned int num;
277 struct kref ref;
278
279 /* Events on the GSM channel */
280 wait_queue_head_t event;
281
282 /* ldisc send work */
283 struct work_struct tx_work;
284
285 /* Bits for GSM mode decoding */
286
287 /* Framing Layer */
288 u8 *buf;
289 enum gsm_mux_state state;
290 unsigned int len;
291 unsigned int address;
292 unsigned int count;
293 bool escape;
294 enum gsm_encoding encoding;
295 u8 control;
296 u8 fcs;
297 u8 *txframe; /* TX framing buffer */
298
299 /* Method for the receiver side */
300 void (*receive)(struct gsm_mux *gsm, u8 ch);
301
302 /* Link Layer */
303 unsigned int mru;
304 unsigned int mtu;
305 int initiator; /* Did we initiate connection */
306 bool dead; /* Has the mux been shut down */
307 struct gsm_dlci *dlci[NUM_DLCI];
308 int old_c_iflag; /* termios c_iflag value before attach */
309 bool constipated; /* Asked by remote to shut up */
310 bool has_devices; /* Devices were registered */
311
312 spinlock_t tx_lock;
313 unsigned int tx_bytes; /* TX data outstanding */
314#define TX_THRESH_HI 8192
315#define TX_THRESH_LO 2048
316 struct list_head tx_ctrl_list; /* Pending control packets */
317 struct list_head tx_data_list; /* Pending data packets */
318
319 /* Control messages */
320 struct timer_list kick_timer; /* Kick TX queuing on timeout */
321 struct timer_list t2_timer; /* Retransmit timer for commands */
322 int cretries; /* Command retry counter */
323 struct gsm_control *pending_cmd;/* Our current pending command */
324 spinlock_t control_lock; /* Protects the pending command */
325
326 /* Keep-alive */
327 struct timer_list ka_timer; /* Keep-alive response timer */
328 u8 ka_num; /* Keep-alive match pattern */
329 signed int ka_retries; /* Keep-alive retry counter, -1 if not yet initialized */
330
331 /* Configuration */
332 int adaption; /* 1 or 2 supported */
333 u8 ftype; /* UI or UIH */
334 int t1, t2; /* Timers in 1/100th of a sec */
335 unsigned int t3; /* Power wake-up timer in seconds. */
336 int n2; /* Retry count */
337 u8 k; /* Window size */
338 bool wait_config; /* Wait for configuration by ioctl before DLCI open */
339 u32 keep_alive; /* Control channel keep-alive in 10ms */
340
341 /* Statistics (not currently exposed) */
342 unsigned long bad_fcs;
343 unsigned long malformed;
344 unsigned long io_error;
345 unsigned long open_error;
346 unsigned long bad_size;
347 unsigned long unsupported;
348};
349
350
351/*
352 * Mux objects - needed so that we can translate a tty index into the
353 * relevant mux and DLCI.
354 */
355
356#define MAX_MUX 4 /* 256 minors */
357static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
358static DEFINE_SPINLOCK(gsm_mux_lock);
359
360static struct tty_driver *gsm_tty_driver;
361
362/*
363 * This section of the driver logic implements the GSM encodings
364 * both the basic and the 'advanced'. Reliable transport is not
365 * supported.
366 */
367
368#define CR 0x02
369#define EA 0x01
370#define PF 0x10
371
372/* I is special: the rest are ..*/
373#define RR 0x01
374#define UI 0x03
375#define RNR 0x05
376#define REJ 0x09
377#define DM 0x0F
378#define SABM 0x2F
379#define DISC 0x43
380#define UA 0x63
381#define UIH 0xEF
382
383/* Channel commands */
384#define CMD_NSC 0x09
385#define CMD_TEST 0x11
386#define CMD_PSC 0x21
387#define CMD_RLS 0x29
388#define CMD_FCOFF 0x31
389#define CMD_PN 0x41
390#define CMD_RPN 0x49
391#define CMD_FCON 0x51
392#define CMD_CLD 0x61
393#define CMD_SNC 0x69
394#define CMD_MSC 0x71
395
396/* Virtual modem bits */
397#define MDM_FC 0x01
398#define MDM_RTC 0x02
399#define MDM_RTR 0x04
400#define MDM_IC 0x20
401#define MDM_DV 0x40
402
403#define GSM0_SOF 0xF9
404#define GSM1_SOF 0x7E
405#define GSM1_ESCAPE 0x7D
406#define GSM1_ESCAPE_BITS 0x20
407#define XON 0x11
408#define XOFF 0x13
409#define ISO_IEC_646_MASK 0x7F
410
411static const struct tty_port_operations gsm_port_ops;
412
413/*
414 * CRC table for GSM 0710
415 */
416
417static const u8 gsm_fcs8[256] = {
418 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
419 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
420 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
421 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
422 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
423 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
424 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
425 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
426 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
427 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
428 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
429 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
430 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
431 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
432 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
433 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
434 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
435 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
436 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
437 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
438 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
439 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
440 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
441 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
442 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
443 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
444 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
445 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
446 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
447 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
448 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
449 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
450};
451
452#define INIT_FCS 0xFF
453#define GOOD_FCS 0xCF
454
455static void gsm_dlci_close(struct gsm_dlci *dlci);
456static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len);
457static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk, bool wait);
458static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
459 u8 ctrl);
460static int gsm_send_packet(struct gsm_mux *gsm, struct gsm_msg *msg);
461static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr);
462static void gsmld_write_trigger(struct gsm_mux *gsm);
463static void gsmld_write_task(struct work_struct *work);
464
465/**
466 * gsm_fcs_add - update FCS
467 * @fcs: Current FCS
468 * @c: Next data
469 *
470 * Update the FCS to include c. Uses the algorithm in the specification
471 * notes.
472 */
473
474static inline u8 gsm_fcs_add(u8 fcs, u8 c)
475{
476 return gsm_fcs8[fcs ^ c];
477}
478
479/**
480 * gsm_fcs_add_block - update FCS for a block
481 * @fcs: Current FCS
482 * @c: buffer of data
483 * @len: length of buffer
484 *
485 * Update the FCS to include c. Uses the algorithm in the specification
486 * notes.
487 */
488
489static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
490{
491 while (len--)
492 fcs = gsm_fcs8[fcs ^ *c++];
493 return fcs;
494}
495
496/**
497 * gsm_read_ea - read a byte into an EA
498 * @val: variable holding value
499 * @c: byte going into the EA
500 *
501 * Processes one byte of an EA. Updates the passed variable
502 * and returns 1 if the EA is now completely read
503 */
504
505static int gsm_read_ea(unsigned int *val, u8 c)
506{
507 /* Add the next 7 bits into the value */
508 *val <<= 7;
509 *val |= c >> 1;
510 /* Was this the last byte of the EA 1 = yes*/
511 return c & EA;
512}
513
514/**
515 * gsm_read_ea_val - read a value until EA
516 * @val: variable holding value
517 * @data: buffer of data
518 * @dlen: length of data
519 *
520 * Processes an EA value. Updates the passed variable and
521 * returns the processed data length.
522 */
523static unsigned int gsm_read_ea_val(unsigned int *val, const u8 *data, int dlen)
524{
525 unsigned int len = 0;
526
527 for (; dlen > 0; dlen--) {
528 len++;
529 if (gsm_read_ea(val, *data++))
530 break;
531 }
532 return len;
533}
534
535/**
536 * gsm_encode_modem - encode modem data bits
537 * @dlci: DLCI to encode from
538 *
539 * Returns the correct GSM encoded modem status bits (6 bit field) for
540 * the current status of the DLCI and attached tty object
541 */
542
543static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
544{
545 u8 modembits = 0;
546 /* FC is true flow control not modem bits */
547 if (dlci->throttled)
548 modembits |= MDM_FC;
549 if (dlci->modem_tx & TIOCM_DTR)
550 modembits |= MDM_RTC;
551 if (dlci->modem_tx & TIOCM_RTS)
552 modembits |= MDM_RTR;
553 if (dlci->modem_tx & TIOCM_RI)
554 modembits |= MDM_IC;
555 if (dlci->modem_tx & TIOCM_CD || dlci->gsm->initiator)
556 modembits |= MDM_DV;
557 /* special mappings for passive side to operate as UE */
558 if (dlci->modem_tx & TIOCM_OUT1)
559 modembits |= MDM_IC;
560 if (dlci->modem_tx & TIOCM_OUT2)
561 modembits |= MDM_DV;
562 return modembits;
563}
564
565static void gsm_hex_dump_bytes(const char *fname, const u8 *data,
566 unsigned long len)
567{
568 char *prefix;
569
570 if (!fname) {
571 print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, 16, 1, data, len,
572 true);
573 return;
574 }
575
576 prefix = kasprintf(GFP_ATOMIC, "%s: ", fname);
577 if (!prefix)
578 return;
579 print_hex_dump(KERN_INFO, prefix, DUMP_PREFIX_OFFSET, 16, 1, data, len,
580 true);
581 kfree(prefix);
582}
583
584/**
585 * gsm_encode_params - encode DLCI parameters
586 * @dlci: DLCI to encode from
587 * @params: buffer to fill with the encoded parameters
588 *
589 * Encodes the parameters according to GSM 07.10 section 5.4.6.3.1
590 * table 3.
591 */
592static int gsm_encode_params(const struct gsm_dlci *dlci,
593 struct gsm_dlci_param_bits *params)
594{
595 const struct gsm_mux *gsm = dlci->gsm;
596 unsigned int i, cl;
597
598 switch (dlci->ftype) {
599 case UIH:
600 i = 0; /* UIH */
601 break;
602 case UI:
603 i = 1; /* UI */
604 break;
605 default:
606 pr_debug("unsupported frame type %d\n", dlci->ftype);
607 return -EINVAL;
608 }
609
610 switch (dlci->adaption) {
611 case 1: /* Unstructured */
612 cl = 0; /* convergence layer type 1 */
613 break;
614 case 2: /* Unstructured with modem bits. */
615 cl = 1; /* convergence layer type 2 */
616 break;
617 default:
618 pr_debug("unsupported adaption %d\n", dlci->adaption);
619 return -EINVAL;
620 }
621
622 params->d_bits = FIELD_PREP(PN_D_FIELD_DLCI, dlci->addr);
623 /* UIH, convergence layer type 1 */
624 params->i_cl_bits = FIELD_PREP(PN_I_CL_FIELD_FTYPE, i) |
625 FIELD_PREP(PN_I_CL_FIELD_ADAPTION, cl);
626 params->p_bits = FIELD_PREP(PN_P_FIELD_PRIO, dlci->prio);
627 params->t_bits = FIELD_PREP(PN_T_FIELD_T1, gsm->t1);
628 params->n_bits = cpu_to_le16(FIELD_PREP(PN_N_FIELD_N1, dlci->mtu));
629 params->na_bits = FIELD_PREP(PN_NA_FIELD_N2, gsm->n2);
630 params->k_bits = FIELD_PREP(PN_K_FIELD_K, dlci->k);
631
632 return 0;
633}
634
635/**
636 * gsm_register_devices - register all tty devices for a given mux index
637 *
638 * @driver: the tty driver that describes the tty devices
639 * @index: the mux number is used to calculate the minor numbers of the
640 * ttys for this mux and may differ from the position in the
641 * mux array.
642 */
643static int gsm_register_devices(struct tty_driver *driver, unsigned int index)
644{
645 struct device *dev;
646 int i;
647 unsigned int base;
648
649 if (!driver || index >= MAX_MUX)
650 return -EINVAL;
651
652 base = index * NUM_DLCI; /* first minor for this index */
653 for (i = 1; i < NUM_DLCI; i++) {
654 /* Don't register device 0 - this is the control channel
655 * and not a usable tty interface
656 */
657 dev = tty_register_device(gsm_tty_driver, base + i, NULL);
658 if (IS_ERR(dev)) {
659 if (debug & DBG_ERRORS)
660 pr_info("%s failed to register device minor %u",
661 __func__, base + i);
662 for (i--; i >= 1; i--)
663 tty_unregister_device(gsm_tty_driver, base + i);
664 return PTR_ERR(dev);
665 }
666 }
667
668 return 0;
669}
670
671/**
672 * gsm_unregister_devices - unregister all tty devices for a given mux index
673 *
674 * @driver: the tty driver that describes the tty devices
675 * @index: the mux number is used to calculate the minor numbers of the
676 * ttys for this mux and may differ from the position in the
677 * mux array.
678 */
679static void gsm_unregister_devices(struct tty_driver *driver,
680 unsigned int index)
681{
682 int i;
683 unsigned int base;
684
685 if (!driver || index >= MAX_MUX)
686 return;
687
688 base = index * NUM_DLCI; /* first minor for this index */
689 for (i = 1; i < NUM_DLCI; i++) {
690 /* Don't unregister device 0 - this is the control
691 * channel and not a usable tty interface
692 */
693 tty_unregister_device(gsm_tty_driver, base + i);
694 }
695}
696
697/**
698 * gsm_print_packet - display a frame for debug
699 * @hdr: header to print before decode
700 * @addr: address EA from the frame
701 * @cr: C/R bit seen as initiator
702 * @control: control including PF bit
703 * @data: following data bytes
704 * @dlen: length of data
705 *
706 * Displays a packet in human readable format for debugging purposes. The
707 * style is based on amateur radio LAP-B dump display.
708 */
709
710static void gsm_print_packet(const char *hdr, int addr, int cr,
711 u8 control, const u8 *data, int dlen)
712{
713 if (!(debug & DBG_DUMP))
714 return;
715 /* Only show user payload frames if debug & DBG_PAYLOAD */
716 if (!(debug & DBG_PAYLOAD) && addr != 0)
717 if ((control & ~PF) == UI || (control & ~PF) == UIH)
718 return;
719
720 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
721
722 switch (control & ~PF) {
723 case SABM:
724 pr_cont("SABM");
725 break;
726 case UA:
727 pr_cont("UA");
728 break;
729 case DISC:
730 pr_cont("DISC");
731 break;
732 case DM:
733 pr_cont("DM");
734 break;
735 case UI:
736 pr_cont("UI");
737 break;
738 case UIH:
739 pr_cont("UIH");
740 break;
741 default:
742 if (!(control & 0x01)) {
743 pr_cont("I N(S)%d N(R)%d",
744 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
745 } else switch (control & 0x0F) {
746 case RR:
747 pr_cont("RR(%d)", (control & 0xE0) >> 5);
748 break;
749 case RNR:
750 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
751 break;
752 case REJ:
753 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
754 break;
755 default:
756 pr_cont("[%02X]", control);
757 }
758 }
759
760 if (control & PF)
761 pr_cont("(P)");
762 else
763 pr_cont("(F)");
764
765 gsm_hex_dump_bytes(NULL, data, dlen);
766}
767
768
769/*
770 * Link level transmission side
771 */
772
773/**
774 * gsm_stuff_frame - bytestuff a packet
775 * @input: input buffer
776 * @output: output buffer
777 * @len: length of input
778 *
779 * Expand a buffer by bytestuffing it. The worst case size change
780 * is doubling and the caller is responsible for handing out
781 * suitable sized buffers.
782 */
783
784static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
785{
786 int olen = 0;
787 while (len--) {
788 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
789 || (*input & ISO_IEC_646_MASK) == XON
790 || (*input & ISO_IEC_646_MASK) == XOFF) {
791 *output++ = GSM1_ESCAPE;
792 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
793 olen++;
794 } else
795 *output++ = *input++;
796 olen++;
797 }
798 return olen;
799}
800
801/**
802 * gsm_send - send a control frame
803 * @gsm: our GSM mux
804 * @addr: address for control frame
805 * @cr: command/response bit seen as initiator
806 * @control: control byte including PF bit
807 *
808 * Format up and transmit a control frame. These should be transmitted
809 * ahead of data when they are needed.
810 */
811static int gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
812{
813 struct gsm_msg *msg;
814 u8 *dp;
815 int ocr;
816 unsigned long flags;
817
818 msg = gsm_data_alloc(gsm, addr, 0, control);
819 if (!msg)
820 return -ENOMEM;
821
822 /* toggle C/R coding if not initiator */
823 ocr = cr ^ (gsm->initiator ? 0 : 1);
824
825 msg->data -= 3;
826 dp = msg->data;
827 *dp++ = (addr << 2) | (ocr << 1) | EA;
828 *dp++ = control;
829
830 if (gsm->encoding == GSM_BASIC_OPT)
831 *dp++ = EA; /* Length of data = 0 */
832
833 *dp = 0xFF - gsm_fcs_add_block(INIT_FCS, msg->data, dp - msg->data);
834 msg->len = (dp - msg->data) + 1;
835
836 gsm_print_packet("Q->", addr, cr, control, NULL, 0);
837
838 spin_lock_irqsave(&gsm->tx_lock, flags);
839 list_add_tail(&msg->list, &gsm->tx_ctrl_list);
840 gsm->tx_bytes += msg->len;
841 spin_unlock_irqrestore(&gsm->tx_lock, flags);
842 gsmld_write_trigger(gsm);
843
844 return 0;
845}
846
847/**
848 * gsm_dlci_clear_queues - remove outstanding data for a DLCI
849 * @gsm: mux
850 * @dlci: clear for this DLCI
851 *
852 * Clears the data queues for a given DLCI.
853 */
854static void gsm_dlci_clear_queues(struct gsm_mux *gsm, struct gsm_dlci *dlci)
855{
856 struct gsm_msg *msg, *nmsg;
857 int addr = dlci->addr;
858 unsigned long flags;
859
860 /* Clear DLCI write fifo first */
861 spin_lock_irqsave(&dlci->lock, flags);
862 kfifo_reset(&dlci->fifo);
863 spin_unlock_irqrestore(&dlci->lock, flags);
864
865 /* Clear data packets in MUX write queue */
866 spin_lock_irqsave(&gsm->tx_lock, flags);
867 list_for_each_entry_safe(msg, nmsg, &gsm->tx_data_list, list) {
868 if (msg->addr != addr)
869 continue;
870 gsm->tx_bytes -= msg->len;
871 list_del(&msg->list);
872 kfree(msg);
873 }
874 spin_unlock_irqrestore(&gsm->tx_lock, flags);
875}
876
877/**
878 * gsm_response - send a control response
879 * @gsm: our GSM mux
880 * @addr: address for control frame
881 * @control: control byte including PF bit
882 *
883 * Format up and transmit a link level response frame.
884 */
885
886static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
887{
888 gsm_send(gsm, addr, 0, control);
889}
890
891/**
892 * gsm_command - send a control command
893 * @gsm: our GSM mux
894 * @addr: address for control frame
895 * @control: control byte including PF bit
896 *
897 * Format up and transmit a link level command frame.
898 */
899
900static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
901{
902 gsm_send(gsm, addr, 1, control);
903}
904
905/* Data transmission */
906
907#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
908
909/**
910 * gsm_data_alloc - allocate data frame
911 * @gsm: GSM mux
912 * @addr: DLCI address
913 * @len: length excluding header and FCS
914 * @ctrl: control byte
915 *
916 * Allocate a new data buffer for sending frames with data. Space is left
917 * at the front for header bytes but that is treated as an implementation
918 * detail and not for the high level code to use
919 */
920
921static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
922 u8 ctrl)
923{
924 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
925 GFP_ATOMIC);
926 if (m == NULL)
927 return NULL;
928 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
929 m->len = len;
930 m->addr = addr;
931 m->ctrl = ctrl;
932 INIT_LIST_HEAD(&m->list);
933 return m;
934}
935
936/**
937 * gsm_send_packet - sends a single packet
938 * @gsm: GSM Mux
939 * @msg: packet to send
940 *
941 * The given packet is encoded and sent out. No memory is freed.
942 * The caller must hold the gsm tx lock.
943 */
944static int gsm_send_packet(struct gsm_mux *gsm, struct gsm_msg *msg)
945{
946 int len, ret;
947
948
949 if (gsm->encoding == GSM_BASIC_OPT) {
950 gsm->txframe[0] = GSM0_SOF;
951 memcpy(gsm->txframe + 1, msg->data, msg->len);
952 gsm->txframe[msg->len + 1] = GSM0_SOF;
953 len = msg->len + 2;
954 } else {
955 gsm->txframe[0] = GSM1_SOF;
956 len = gsm_stuff_frame(msg->data, gsm->txframe + 1, msg->len);
957 gsm->txframe[len + 1] = GSM1_SOF;
958 len += 2;
959 }
960
961 if (debug & DBG_DATA)
962 gsm_hex_dump_bytes(__func__, gsm->txframe, len);
963 gsm_print_packet("-->", msg->addr, gsm->initiator, msg->ctrl, msg->data,
964 msg->len);
965
966 ret = gsmld_output(gsm, gsm->txframe, len);
967 if (ret <= 0)
968 return ret;
969 /* FIXME: Can eliminate one SOF in many more cases */
970 gsm->tx_bytes -= msg->len;
971
972 return 0;
973}
974
975/**
976 * gsm_is_flow_ctrl_msg - checks if flow control message
977 * @msg: message to check
978 *
979 * Returns true if the given message is a flow control command of the
980 * control channel. False is returned in any other case.
981 */
982static bool gsm_is_flow_ctrl_msg(struct gsm_msg *msg)
983{
984 unsigned int cmd;
985
986 if (msg->addr > 0)
987 return false;
988
989 switch (msg->ctrl & ~PF) {
990 case UI:
991 case UIH:
992 cmd = 0;
993 if (gsm_read_ea_val(&cmd, msg->data + 2, msg->len - 2) < 1)
994 break;
995 switch (cmd & ~PF) {
996 case CMD_FCOFF:
997 case CMD_FCON:
998 return true;
999 }
1000 break;
1001 }
1002
1003 return false;
1004}
1005
1006/**
1007 * gsm_data_kick - poke the queue
1008 * @gsm: GSM Mux
1009 *
1010 * The tty device has called us to indicate that room has appeared in
1011 * the transmit queue. Ram more data into the pipe if we have any.
1012 * If we have been flow-stopped by a CMD_FCOFF, then we can only
1013 * send messages on DLCI0 until CMD_FCON. The caller must hold
1014 * the gsm tx lock.
1015 */
1016static int gsm_data_kick(struct gsm_mux *gsm)
1017{
1018 struct gsm_msg *msg, *nmsg;
1019 struct gsm_dlci *dlci;
1020 int ret;
1021
1022 clear_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
1023
1024 /* Serialize control messages and control channel messages first */
1025 list_for_each_entry_safe(msg, nmsg, &gsm->tx_ctrl_list, list) {
1026 if (gsm->constipated && !gsm_is_flow_ctrl_msg(msg))
1027 continue;
1028 ret = gsm_send_packet(gsm, msg);
1029 switch (ret) {
1030 case -ENOSPC:
1031 return -ENOSPC;
1032 case -ENODEV:
1033 /* ldisc not open */
1034 gsm->tx_bytes -= msg->len;
1035 list_del(&msg->list);
1036 kfree(msg);
1037 continue;
1038 default:
1039 if (ret >= 0) {
1040 list_del(&msg->list);
1041 kfree(msg);
1042 }
1043 break;
1044 }
1045 }
1046
1047 if (gsm->constipated)
1048 return -EAGAIN;
1049
1050 /* Serialize other channels */
1051 if (list_empty(&gsm->tx_data_list))
1052 return 0;
1053 list_for_each_entry_safe(msg, nmsg, &gsm->tx_data_list, list) {
1054 dlci = gsm->dlci[msg->addr];
1055 /* Send only messages for DLCIs with valid state */
1056 if (dlci->state != DLCI_OPEN) {
1057 gsm->tx_bytes -= msg->len;
1058 list_del(&msg->list);
1059 kfree(msg);
1060 continue;
1061 }
1062 ret = gsm_send_packet(gsm, msg);
1063 switch (ret) {
1064 case -ENOSPC:
1065 return -ENOSPC;
1066 case -ENODEV:
1067 /* ldisc not open */
1068 gsm->tx_bytes -= msg->len;
1069 list_del(&msg->list);
1070 kfree(msg);
1071 continue;
1072 default:
1073 if (ret >= 0) {
1074 list_del(&msg->list);
1075 kfree(msg);
1076 }
1077 break;
1078 }
1079 }
1080
1081 return 1;
1082}
1083
1084/**
1085 * __gsm_data_queue - queue a UI or UIH frame
1086 * @dlci: DLCI sending the data
1087 * @msg: message queued
1088 *
1089 * Add data to the transmit queue and try and get stuff moving
1090 * out of the mux tty if not already doing so. The Caller must hold
1091 * the gsm tx lock.
1092 */
1093
1094static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
1095{
1096 struct gsm_mux *gsm = dlci->gsm;
1097 u8 *dp = msg->data;
1098 u8 *fcs = dp + msg->len;
1099
1100 /* Fill in the header */
1101 if (gsm->encoding == GSM_BASIC_OPT) {
1102 if (msg->len < 128)
1103 *--dp = (msg->len << 1) | EA;
1104 else {
1105 *--dp = (msg->len >> 7); /* bits 7 - 15 */
1106 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
1107 }
1108 }
1109
1110 *--dp = msg->ctrl;
1111 if (gsm->initiator)
1112 *--dp = (msg->addr << 2) | CR | EA;
1113 else
1114 *--dp = (msg->addr << 2) | EA;
1115 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
1116 /* Ugly protocol layering violation */
1117 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
1118 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
1119 *fcs = 0xFF - *fcs;
1120
1121 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
1122 msg->data, msg->len);
1123
1124 /* Move the header back and adjust the length, also allow for the FCS
1125 now tacked on the end */
1126 msg->len += (msg->data - dp) + 1;
1127 msg->data = dp;
1128
1129 /* Add to the actual output queue */
1130 switch (msg->ctrl & ~PF) {
1131 case UI:
1132 case UIH:
1133 if (msg->addr > 0) {
1134 list_add_tail(&msg->list, &gsm->tx_data_list);
1135 break;
1136 }
1137 fallthrough;
1138 default:
1139 list_add_tail(&msg->list, &gsm->tx_ctrl_list);
1140 break;
1141 }
1142 gsm->tx_bytes += msg->len;
1143
1144 gsmld_write_trigger(gsm);
1145 mod_timer(&gsm->kick_timer, jiffies + 10 * gsm->t1 * HZ / 100);
1146}
1147
1148/**
1149 * gsm_data_queue - queue a UI or UIH frame
1150 * @dlci: DLCI sending the data
1151 * @msg: message queued
1152 *
1153 * Add data to the transmit queue and try and get stuff moving
1154 * out of the mux tty if not already doing so. Take the
1155 * the gsm tx lock and dlci lock.
1156 */
1157
1158static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
1159{
1160 unsigned long flags;
1161 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
1162 __gsm_data_queue(dlci, msg);
1163 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
1164}
1165
1166/**
1167 * gsm_dlci_data_output - try and push data out of a DLCI
1168 * @gsm: mux
1169 * @dlci: the DLCI to pull data from
1170 *
1171 * Pull data from a DLCI and send it into the transmit queue if there
1172 * is data. Keep to the MRU of the mux. This path handles the usual tty
1173 * interface which is a byte stream with optional modem data.
1174 *
1175 * Caller must hold the tx_lock of the mux.
1176 */
1177
1178static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
1179{
1180 struct gsm_msg *msg;
1181 u8 *dp;
1182 int h, len, size;
1183
1184 /* for modem bits without break data */
1185 h = ((dlci->adaption == 1) ? 0 : 1);
1186
1187 len = kfifo_len(&dlci->fifo);
1188 if (len == 0)
1189 return 0;
1190
1191 /* MTU/MRU count only the data bits but watch adaption mode */
1192 if ((len + h) > dlci->mtu)
1193 len = dlci->mtu - h;
1194
1195 size = len + h;
1196
1197 msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype);
1198 if (!msg)
1199 return -ENOMEM;
1200 dp = msg->data;
1201 switch (dlci->adaption) {
1202 case 1: /* Unstructured */
1203 break;
1204 case 2: /* Unstructured with modem bits.
1205 * Always one byte as we never send inline break data
1206 */
1207 *dp++ = (gsm_encode_modem(dlci) << 1) | EA;
1208 break;
1209 default:
1210 pr_err("%s: unsupported adaption %d\n", __func__,
1211 dlci->adaption);
1212 break;
1213 }
1214
1215 WARN_ON(len != kfifo_out_locked(&dlci->fifo, dp, len,
1216 &dlci->lock));
1217
1218 /* Notify upper layer about available send space. */
1219 tty_port_tty_wakeup(&dlci->port);
1220
1221 __gsm_data_queue(dlci, msg);
1222 /* Bytes of data we used up */
1223 return size;
1224}
1225
1226/**
1227 * gsm_dlci_data_output_framed - try and push data out of a DLCI
1228 * @gsm: mux
1229 * @dlci: the DLCI to pull data from
1230 *
1231 * Pull data from a DLCI and send it into the transmit queue if there
1232 * is data. Keep to the MRU of the mux. This path handles framed data
1233 * queued as skbuffs to the DLCI.
1234 *
1235 * Caller must hold the tx_lock of the mux.
1236 */
1237
1238static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
1239 struct gsm_dlci *dlci)
1240{
1241 struct gsm_msg *msg;
1242 u8 *dp;
1243 int len, size;
1244 int last = 0, first = 0;
1245 int overhead = 0;
1246
1247 /* One byte per frame is used for B/F flags */
1248 if (dlci->adaption == 4)
1249 overhead = 1;
1250
1251 /* dlci->skb is locked by tx_lock */
1252 if (dlci->skb == NULL) {
1253 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
1254 if (dlci->skb == NULL)
1255 return 0;
1256 first = 1;
1257 }
1258 len = dlci->skb->len + overhead;
1259
1260 /* MTU/MRU count only the data bits */
1261 if (len > dlci->mtu) {
1262 if (dlci->adaption == 3) {
1263 /* Over long frame, bin it */
1264 dev_kfree_skb_any(dlci->skb);
1265 dlci->skb = NULL;
1266 return 0;
1267 }
1268 len = dlci->mtu;
1269 } else
1270 last = 1;
1271
1272 size = len + overhead;
1273 msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype);
1274 if (msg == NULL) {
1275 skb_queue_tail(&dlci->skb_list, dlci->skb);
1276 dlci->skb = NULL;
1277 return -ENOMEM;
1278 }
1279 dp = msg->data;
1280
1281 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
1282 /* Flag byte to carry the start/end info */
1283 *dp++ = last << 7 | first << 6 | 1; /* EA */
1284 len--;
1285 }
1286 memcpy(dp, dlci->skb->data, len);
1287 skb_pull(dlci->skb, len);
1288 __gsm_data_queue(dlci, msg);
1289 if (last) {
1290 dev_kfree_skb_any(dlci->skb);
1291 dlci->skb = NULL;
1292 }
1293 return size;
1294}
1295
1296/**
1297 * gsm_dlci_modem_output - try and push modem status out of a DLCI
1298 * @gsm: mux
1299 * @dlci: the DLCI to pull modem status from
1300 * @brk: break signal
1301 *
1302 * Push an empty frame in to the transmit queue to update the modem status
1303 * bits and to transmit an optional break.
1304 *
1305 * Caller must hold the tx_lock of the mux.
1306 */
1307
1308static int gsm_dlci_modem_output(struct gsm_mux *gsm, struct gsm_dlci *dlci,
1309 u8 brk)
1310{
1311 u8 *dp = NULL;
1312 struct gsm_msg *msg;
1313 int size = 0;
1314
1315 /* for modem bits without break data */
1316 switch (dlci->adaption) {
1317 case 1: /* Unstructured */
1318 break;
1319 case 2: /* Unstructured with modem bits. */
1320 size++;
1321 if (brk > 0)
1322 size++;
1323 break;
1324 default:
1325 pr_err("%s: unsupported adaption %d\n", __func__,
1326 dlci->adaption);
1327 return -EINVAL;
1328 }
1329
1330 msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype);
1331 if (!msg) {
1332 pr_err("%s: gsm_data_alloc error", __func__);
1333 return -ENOMEM;
1334 }
1335 dp = msg->data;
1336 switch (dlci->adaption) {
1337 case 1: /* Unstructured */
1338 break;
1339 case 2: /* Unstructured with modem bits. */
1340 if (brk == 0) {
1341 *dp++ = (gsm_encode_modem(dlci) << 1) | EA;
1342 } else {
1343 *dp++ = gsm_encode_modem(dlci) << 1;
1344 *dp++ = (brk << 4) | 2 | EA; /* Length, Break, EA */
1345 }
1346 break;
1347 default:
1348 /* Handled above */
1349 break;
1350 }
1351
1352 __gsm_data_queue(dlci, msg);
1353 return size;
1354}
1355
1356/**
1357 * gsm_dlci_data_sweep - look for data to send
1358 * @gsm: the GSM mux
1359 *
1360 * Sweep the GSM mux channels in priority order looking for ones with
1361 * data to send. We could do with optimising this scan a bit. We aim
1362 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
1363 * TX_THRESH_LO we get called again
1364 *
1365 * FIXME: We should round robin between groups and in theory you can
1366 * renegotiate DLCI priorities with optional stuff. Needs optimising.
1367 */
1368
1369static int gsm_dlci_data_sweep(struct gsm_mux *gsm)
1370{
1371 /* Priority ordering: We should do priority with RR of the groups */
1372 int i, len, ret = 0;
1373 bool sent;
1374 struct gsm_dlci *dlci;
1375
1376 while (gsm->tx_bytes < TX_THRESH_HI) {
1377 for (sent = false, i = 1; i < NUM_DLCI; i++) {
1378 dlci = gsm->dlci[i];
1379 /* skip unused or blocked channel */
1380 if (!dlci || dlci->constipated)
1381 continue;
1382 /* skip channels with invalid state */
1383 if (dlci->state != DLCI_OPEN)
1384 continue;
1385 /* count the sent data per adaption */
1386 if (dlci->adaption < 3 && !dlci->net)
1387 len = gsm_dlci_data_output(gsm, dlci);
1388 else
1389 len = gsm_dlci_data_output_framed(gsm, dlci);
1390 /* on error exit */
1391 if (len < 0)
1392 return ret;
1393 if (len > 0) {
1394 ret++;
1395 sent = true;
1396 /* The lower DLCs can starve the higher DLCs! */
1397 break;
1398 }
1399 /* try next */
1400 }
1401 if (!sent)
1402 break;
1403 }
1404
1405 return ret;
1406}
1407
1408/**
1409 * gsm_dlci_data_kick - transmit if possible
1410 * @dlci: DLCI to kick
1411 *
1412 * Transmit data from this DLCI if the queue is empty. We can't rely on
1413 * a tty wakeup except when we filled the pipe so we need to fire off
1414 * new data ourselves in other cases.
1415 */
1416
1417static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
1418{
1419 unsigned long flags;
1420 int sweep;
1421
1422 if (dlci->constipated)
1423 return;
1424
1425 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
1426 /* If we have nothing running then we need to fire up */
1427 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
1428 if (dlci->gsm->tx_bytes == 0) {
1429 if (dlci->net)
1430 gsm_dlci_data_output_framed(dlci->gsm, dlci);
1431 else
1432 gsm_dlci_data_output(dlci->gsm, dlci);
1433 }
1434 if (sweep)
1435 gsm_dlci_data_sweep(dlci->gsm);
1436 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
1437}
1438
1439/*
1440 * Control message processing
1441 */
1442
1443
1444/**
1445 * gsm_control_command - send a command frame to a control
1446 * @gsm: gsm channel
1447 * @cmd: the command to use
1448 * @data: data to follow encoded info
1449 * @dlen: length of data
1450 *
1451 * Encode up and queue a UI/UIH frame containing our command.
1452 */
1453static int gsm_control_command(struct gsm_mux *gsm, int cmd, const u8 *data,
1454 int dlen)
1455{
1456 struct gsm_msg *msg;
1457 struct gsm_dlci *dlci = gsm->dlci[0];
1458
1459 msg = gsm_data_alloc(gsm, 0, dlen + 2, dlci->ftype);
1460 if (msg == NULL)
1461 return -ENOMEM;
1462
1463 msg->data[0] = (cmd << 1) | CR | EA; /* Set C/R */
1464 msg->data[1] = (dlen << 1) | EA;
1465 memcpy(msg->data + 2, data, dlen);
1466 gsm_data_queue(dlci, msg);
1467
1468 return 0;
1469}
1470
1471/**
1472 * gsm_control_reply - send a response frame to a control
1473 * @gsm: gsm channel
1474 * @cmd: the command to use
1475 * @data: data to follow encoded info
1476 * @dlen: length of data
1477 *
1478 * Encode up and queue a UI/UIH frame containing our response.
1479 */
1480
1481static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data,
1482 int dlen)
1483{
1484 struct gsm_msg *msg;
1485 struct gsm_dlci *dlci = gsm->dlci[0];
1486
1487 msg = gsm_data_alloc(gsm, 0, dlen + 2, dlci->ftype);
1488 if (msg == NULL)
1489 return;
1490 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1491 msg->data[1] = (dlen << 1) | EA;
1492 memcpy(msg->data + 2, data, dlen);
1493 gsm_data_queue(dlci, msg);
1494}
1495
1496/**
1497 * gsm_process_modem - process received modem status
1498 * @tty: virtual tty bound to the DLCI
1499 * @dlci: DLCI to affect
1500 * @modem: modem bits (full EA)
1501 * @slen: number of signal octets
1502 *
1503 * Used when a modem control message or line state inline in adaption
1504 * layer 2 is processed. Sort out the local modem state and throttles
1505 */
1506
1507static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1508 u32 modem, int slen)
1509{
1510 int mlines = 0;
1511 u8 brk = 0;
1512 int fc;
1513
1514 /* The modem status command can either contain one octet (V.24 signals)
1515 * or two octets (V.24 signals + break signals). This is specified in
1516 * section 5.4.6.3.7 of the 07.10 mux spec.
1517 */
1518
1519 if (slen == 1)
1520 modem = modem & 0x7f;
1521 else {
1522 brk = modem & 0x7f;
1523 modem = (modem >> 7) & 0x7f;
1524 }
1525
1526 /* Flow control/ready to communicate */
1527 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1528 if (fc && !dlci->constipated) {
1529 /* Need to throttle our output on this device */
1530 dlci->constipated = true;
1531 } else if (!fc && dlci->constipated) {
1532 dlci->constipated = false;
1533 gsm_dlci_data_kick(dlci);
1534 }
1535
1536 /* Map modem bits */
1537 if (modem & MDM_RTC)
1538 mlines |= TIOCM_DSR | TIOCM_DTR;
1539 if (modem & MDM_RTR)
1540 mlines |= TIOCM_RTS | TIOCM_CTS;
1541 if (modem & MDM_IC)
1542 mlines |= TIOCM_RI;
1543 if (modem & MDM_DV)
1544 mlines |= TIOCM_CD;
1545
1546 /* Carrier drop -> hangup */
1547 if (tty) {
1548 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1549 if (!C_CLOCAL(tty))
1550 tty_hangup(tty);
1551 }
1552 if (brk & 0x01)
1553 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1554 dlci->modem_rx = mlines;
1555 wake_up_interruptible(&dlci->gsm->event);
1556}
1557
1558/**
1559 * gsm_process_negotiation - process received parameters
1560 * @gsm: GSM channel
1561 * @addr: DLCI address
1562 * @cr: command/response
1563 * @params: encoded parameters from the parameter negotiation message
1564 *
1565 * Used when the response for our parameter negotiation command was
1566 * received.
1567 */
1568static int gsm_process_negotiation(struct gsm_mux *gsm, unsigned int addr,
1569 unsigned int cr,
1570 const struct gsm_dlci_param_bits *params)
1571{
1572 struct gsm_dlci *dlci = gsm->dlci[addr];
1573 unsigned int ftype, i, adaption, prio, n1, k;
1574
1575 i = FIELD_GET(PN_I_CL_FIELD_FTYPE, params->i_cl_bits);
1576 adaption = FIELD_GET(PN_I_CL_FIELD_ADAPTION, params->i_cl_bits) + 1;
1577 prio = FIELD_GET(PN_P_FIELD_PRIO, params->p_bits);
1578 n1 = FIELD_GET(PN_N_FIELD_N1, get_unaligned_le16(&params->n_bits));
1579 k = FIELD_GET(PN_K_FIELD_K, params->k_bits);
1580
1581 if (n1 < MIN_MTU) {
1582 if (debug & DBG_ERRORS)
1583 pr_info("%s N1 out of range in PN\n", __func__);
1584 return -EINVAL;
1585 }
1586
1587 switch (i) {
1588 case 0x00:
1589 ftype = UIH;
1590 break;
1591 case 0x01:
1592 ftype = UI;
1593 break;
1594 case 0x02: /* I frames are not supported */
1595 if (debug & DBG_ERRORS)
1596 pr_info("%s unsupported I frame request in PN\n",
1597 __func__);
1598 gsm->unsupported++;
1599 return -EINVAL;
1600 default:
1601 if (debug & DBG_ERRORS)
1602 pr_info("%s i out of range in PN\n", __func__);
1603 return -EINVAL;
1604 }
1605
1606 if (!cr && gsm->initiator) {
1607 if (adaption != dlci->adaption) {
1608 if (debug & DBG_ERRORS)
1609 pr_info("%s invalid adaption %d in PN\n",
1610 __func__, adaption);
1611 return -EINVAL;
1612 }
1613 if (prio != dlci->prio) {
1614 if (debug & DBG_ERRORS)
1615 pr_info("%s invalid priority %d in PN",
1616 __func__, prio);
1617 return -EINVAL;
1618 }
1619 if (n1 > gsm->mru || n1 > dlci->mtu) {
1620 /* We requested a frame size but the other party wants
1621 * to send larger frames. The standard allows only a
1622 * smaller response value than requested (5.4.6.3.1).
1623 */
1624 if (debug & DBG_ERRORS)
1625 pr_info("%s invalid N1 %d in PN\n", __func__,
1626 n1);
1627 return -EINVAL;
1628 }
1629 dlci->mtu = n1;
1630 if (ftype != dlci->ftype) {
1631 if (debug & DBG_ERRORS)
1632 pr_info("%s invalid i %d in PN\n", __func__, i);
1633 return -EINVAL;
1634 }
1635 if (ftype != UI && ftype != UIH && k > dlci->k) {
1636 if (debug & DBG_ERRORS)
1637 pr_info("%s invalid k %d in PN\n", __func__, k);
1638 return -EINVAL;
1639 }
1640 dlci->k = k;
1641 } else if (cr && !gsm->initiator) {
1642 /* Only convergence layer type 1 and 2 are supported. */
1643 if (adaption != 1 && adaption != 2) {
1644 if (debug & DBG_ERRORS)
1645 pr_info("%s invalid adaption %d in PN\n",
1646 __func__, adaption);
1647 return -EINVAL;
1648 }
1649 dlci->adaption = adaption;
1650 if (n1 > gsm->mru) {
1651 /* Propose a smaller value */
1652 dlci->mtu = gsm->mru;
1653 } else if (n1 > MAX_MTU) {
1654 /* Propose a smaller value */
1655 dlci->mtu = MAX_MTU;
1656 } else {
1657 dlci->mtu = n1;
1658 }
1659 dlci->prio = prio;
1660 dlci->ftype = ftype;
1661 dlci->k = k;
1662 } else {
1663 return -EINVAL;
1664 }
1665
1666 return 0;
1667}
1668
1669/**
1670 * gsm_control_modem - modem status received
1671 * @gsm: GSM channel
1672 * @data: data following command
1673 * @clen: command length
1674 *
1675 * We have received a modem status control message. This is used by
1676 * the GSM mux protocol to pass virtual modem line status and optionally
1677 * to indicate break signals. Unpack it, convert to Linux representation
1678 * and if need be stuff a break message down the tty.
1679 */
1680
1681static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
1682{
1683 unsigned int addr = 0;
1684 unsigned int modem = 0;
1685 struct gsm_dlci *dlci;
1686 int len = clen;
1687 int cl = clen;
1688 const u8 *dp = data;
1689 struct tty_struct *tty;
1690
1691 len = gsm_read_ea_val(&addr, data, cl);
1692 if (len < 1)
1693 return;
1694
1695 addr >>= 1;
1696 /* Closed port, or invalid ? */
1697 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1698 return;
1699 dlci = gsm->dlci[addr];
1700
1701 /* Must be at least one byte following the EA */
1702 if ((cl - len) < 1)
1703 return;
1704
1705 dp += len;
1706 cl -= len;
1707
1708 /* get the modem status */
1709 len = gsm_read_ea_val(&modem, dp, cl);
1710 if (len < 1)
1711 return;
1712
1713 tty = tty_port_tty_get(&dlci->port);
1714 gsm_process_modem(tty, dlci, modem, cl);
1715 if (tty) {
1716 tty_wakeup(tty);
1717 tty_kref_put(tty);
1718 }
1719 gsm_control_reply(gsm, CMD_MSC, data, clen);
1720}
1721
1722/**
1723 * gsm_control_negotiation - parameter negotiation received
1724 * @gsm: GSM channel
1725 * @cr: command/response flag
1726 * @data: data following command
1727 * @dlen: data length
1728 *
1729 * We have received a parameter negotiation message. This is used by
1730 * the GSM mux protocol to configure protocol parameters for a new DLCI.
1731 */
1732static void gsm_control_negotiation(struct gsm_mux *gsm, unsigned int cr,
1733 const u8 *data, unsigned int dlen)
1734{
1735 unsigned int addr;
1736 struct gsm_dlci_param_bits pn_reply;
1737 struct gsm_dlci *dlci;
1738 struct gsm_dlci_param_bits *params;
1739
1740 if (dlen < sizeof(struct gsm_dlci_param_bits)) {
1741 gsm->open_error++;
1742 return;
1743 }
1744
1745 /* Invalid DLCI? */
1746 params = (struct gsm_dlci_param_bits *)data;
1747 addr = FIELD_GET(PN_D_FIELD_DLCI, params->d_bits);
1748 if (addr == 0 || addr >= NUM_DLCI || !gsm->dlci[addr]) {
1749 gsm->open_error++;
1750 return;
1751 }
1752 dlci = gsm->dlci[addr];
1753
1754 /* Too late for parameter negotiation? */
1755 if ((!cr && dlci->state == DLCI_OPENING) || dlci->state == DLCI_OPEN) {
1756 gsm->open_error++;
1757 return;
1758 }
1759
1760 /* Process the received parameters */
1761 if (gsm_process_negotiation(gsm, addr, cr, params) != 0) {
1762 /* Negotiation failed. Close the link. */
1763 if (debug & DBG_ERRORS)
1764 pr_info("%s PN failed\n", __func__);
1765 gsm->open_error++;
1766 gsm_dlci_close(dlci);
1767 return;
1768 }
1769
1770 if (cr) {
1771 /* Reply command with accepted parameters. */
1772 if (gsm_encode_params(dlci, &pn_reply) == 0)
1773 gsm_control_reply(gsm, CMD_PN, (const u8 *)&pn_reply,
1774 sizeof(pn_reply));
1775 else if (debug & DBG_ERRORS)
1776 pr_info("%s PN invalid\n", __func__);
1777 } else if (dlci->state == DLCI_CONFIGURE) {
1778 /* Proceed with link setup by sending SABM before UA */
1779 dlci->state = DLCI_OPENING;
1780 gsm_command(gsm, dlci->addr, SABM|PF);
1781 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1782 } else {
1783 if (debug & DBG_ERRORS)
1784 pr_info("%s PN in invalid state\n", __func__);
1785 gsm->open_error++;
1786 }
1787}
1788
1789/**
1790 * gsm_control_rls - remote line status
1791 * @gsm: GSM channel
1792 * @data: data bytes
1793 * @clen: data length
1794 *
1795 * The modem sends us a two byte message on the control channel whenever
1796 * it wishes to send us an error state from the virtual link. Stuff
1797 * this into the uplink tty if present
1798 */
1799
1800static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen)
1801{
1802 struct tty_port *port;
1803 unsigned int addr = 0;
1804 u8 bits;
1805 int len = clen;
1806 const u8 *dp = data;
1807
1808 while (gsm_read_ea(&addr, *dp++) == 0) {
1809 len--;
1810 if (len == 0)
1811 return;
1812 }
1813 /* Must be at least one byte following ea */
1814 len--;
1815 if (len <= 0)
1816 return;
1817 addr >>= 1;
1818 /* Closed port, or invalid ? */
1819 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1820 return;
1821 /* No error ? */
1822 bits = *dp;
1823 if ((bits & 1) == 0)
1824 return;
1825
1826 port = &gsm->dlci[addr]->port;
1827
1828 if (bits & 2)
1829 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1830 if (bits & 4)
1831 tty_insert_flip_char(port, 0, TTY_PARITY);
1832 if (bits & 8)
1833 tty_insert_flip_char(port, 0, TTY_FRAME);
1834
1835 tty_flip_buffer_push(port);
1836
1837 gsm_control_reply(gsm, CMD_RLS, data, clen);
1838}
1839
1840static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1841
1842/**
1843 * gsm_control_message - DLCI 0 control processing
1844 * @gsm: our GSM mux
1845 * @command: the command EA
1846 * @data: data beyond the command/length EAs
1847 * @clen: length
1848 *
1849 * Input processor for control messages from the other end of the link.
1850 * Processes the incoming request and queues a response frame or an
1851 * NSC response if not supported
1852 */
1853
1854static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1855 const u8 *data, int clen)
1856{
1857 u8 buf[1];
1858
1859 switch (command) {
1860 case CMD_CLD: {
1861 struct gsm_dlci *dlci = gsm->dlci[0];
1862 /* Modem wishes to close down */
1863 if (dlci) {
1864 dlci->dead = true;
1865 gsm->dead = true;
1866 gsm_dlci_begin_close(dlci);
1867 }
1868 }
1869 break;
1870 case CMD_TEST:
1871 /* Modem wishes to test, reply with the data */
1872 gsm_control_reply(gsm, CMD_TEST, data, clen);
1873 break;
1874 case CMD_FCON:
1875 /* Modem can accept data again */
1876 gsm->constipated = false;
1877 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1878 /* Kick the link in case it is idling */
1879 gsmld_write_trigger(gsm);
1880 break;
1881 case CMD_FCOFF:
1882 /* Modem wants us to STFU */
1883 gsm->constipated = true;
1884 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1885 break;
1886 case CMD_MSC:
1887 /* Out of band modem line change indicator for a DLCI */
1888 gsm_control_modem(gsm, data, clen);
1889 break;
1890 case CMD_RLS:
1891 /* Out of band error reception for a DLCI */
1892 gsm_control_rls(gsm, data, clen);
1893 break;
1894 case CMD_PSC:
1895 /* Modem wishes to enter power saving state */
1896 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1897 break;
1898 /* Optional commands */
1899 case CMD_PN:
1900 /* Modem sends a parameter negotiation command */
1901 gsm_control_negotiation(gsm, 1, data, clen);
1902 break;
1903 /* Optional unsupported commands */
1904 case CMD_RPN: /* Remote port negotiation */
1905 case CMD_SNC: /* Service negotiation command */
1906 gsm->unsupported++;
1907 fallthrough;
1908 default:
1909 /* Reply to bad commands with an NSC */
1910 buf[0] = command;
1911 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1912 break;
1913 }
1914}
1915
1916/**
1917 * gsm_control_response - process a response to our control
1918 * @gsm: our GSM mux
1919 * @command: the command (response) EA
1920 * @data: data beyond the command/length EA
1921 * @clen: length
1922 *
1923 * Process a response to an outstanding command. We only allow a single
1924 * control message in flight so this is fairly easy. All the clean up
1925 * is done by the caller, we just update the fields, flag it as done
1926 * and return
1927 */
1928
1929static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1930 const u8 *data, int clen)
1931{
1932 struct gsm_control *ctrl;
1933 struct gsm_dlci *dlci;
1934 unsigned long flags;
1935
1936 spin_lock_irqsave(&gsm->control_lock, flags);
1937
1938 ctrl = gsm->pending_cmd;
1939 dlci = gsm->dlci[0];
1940 command |= 1;
1941 /* Does the reply match our command */
1942 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1943 /* Our command was replied to, kill the retry timer */
1944 timer_delete(&gsm->t2_timer);
1945 gsm->pending_cmd = NULL;
1946 /* Rejected by the other end */
1947 if (command == CMD_NSC)
1948 ctrl->error = -EOPNOTSUPP;
1949 ctrl->done = 1;
1950 wake_up(&gsm->event);
1951 /* Or did we receive the PN response to our PN command */
1952 } else if (command == CMD_PN) {
1953 gsm_control_negotiation(gsm, 0, data, clen);
1954 /* Or did we receive the TEST response to our TEST command */
1955 } else if (command == CMD_TEST && clen == 1 && *data == gsm->ka_num) {
1956 gsm->ka_retries = -1; /* trigger new keep-alive message */
1957 if (dlci && !dlci->dead)
1958 mod_timer(&gsm->ka_timer, jiffies + gsm->keep_alive * HZ / 100);
1959 }
1960 spin_unlock_irqrestore(&gsm->control_lock, flags);
1961}
1962
1963/**
1964 * gsm_control_keep_alive - check timeout or start keep-alive
1965 * @t: timer contained in our gsm object
1966 *
1967 * Called off the keep-alive timer expiry signaling that our link
1968 * partner is not responding anymore. Link will be closed.
1969 * This is also called to startup our timer.
1970 */
1971
1972static void gsm_control_keep_alive(struct timer_list *t)
1973{
1974 struct gsm_mux *gsm = timer_container_of(gsm, t, ka_timer);
1975 unsigned long flags;
1976
1977 spin_lock_irqsave(&gsm->control_lock, flags);
1978 if (gsm->ka_num && gsm->ka_retries == 0) {
1979 /* Keep-alive expired -> close the link */
1980 if (debug & DBG_ERRORS)
1981 pr_debug("%s keep-alive timed out\n", __func__);
1982 spin_unlock_irqrestore(&gsm->control_lock, flags);
1983 if (gsm->dlci[0])
1984 gsm_dlci_begin_close(gsm->dlci[0]);
1985 return;
1986 } else if (gsm->keep_alive && gsm->dlci[0] && !gsm->dlci[0]->dead) {
1987 if (gsm->ka_retries > 0) {
1988 /* T2 expired for keep-alive -> resend */
1989 gsm->ka_retries--;
1990 } else {
1991 /* Start keep-alive timer */
1992 gsm->ka_num++;
1993 if (!gsm->ka_num)
1994 gsm->ka_num++;
1995 gsm->ka_retries = (signed int)gsm->n2;
1996 }
1997 gsm_control_command(gsm, CMD_TEST, &gsm->ka_num,
1998 sizeof(gsm->ka_num));
1999 mod_timer(&gsm->ka_timer,
2000 jiffies + gsm->t2 * HZ / 100);
2001 }
2002 spin_unlock_irqrestore(&gsm->control_lock, flags);
2003}
2004
2005/**
2006 * gsm_control_transmit - send control packet
2007 * @gsm: gsm mux
2008 * @ctrl: frame to send
2009 *
2010 * Send out a pending control command (called under control lock)
2011 */
2012
2013static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
2014{
2015 gsm_control_command(gsm, ctrl->cmd, ctrl->data, ctrl->len);
2016}
2017
2018/**
2019 * gsm_control_retransmit - retransmit a control frame
2020 * @t: timer contained in our gsm object
2021 *
2022 * Called off the T2 timer expiry in order to retransmit control frames
2023 * that have been lost in the system somewhere. The control_lock protects
2024 * us from colliding with another sender or a receive completion event.
2025 * In that situation the timer may still occur in a small window but
2026 * gsm->pending_cmd will be NULL and we just let the timer expire.
2027 */
2028
2029static void gsm_control_retransmit(struct timer_list *t)
2030{
2031 struct gsm_mux *gsm = timer_container_of(gsm, t, t2_timer);
2032 struct gsm_control *ctrl;
2033 unsigned long flags;
2034 spin_lock_irqsave(&gsm->control_lock, flags);
2035 ctrl = gsm->pending_cmd;
2036 if (ctrl) {
2037 if (gsm->cretries == 0 || !gsm->dlci[0] || gsm->dlci[0]->dead) {
2038 gsm->pending_cmd = NULL;
2039 ctrl->error = -ETIMEDOUT;
2040 ctrl->done = 1;
2041 spin_unlock_irqrestore(&gsm->control_lock, flags);
2042 wake_up(&gsm->event);
2043 return;
2044 }
2045 gsm->cretries--;
2046 gsm_control_transmit(gsm, ctrl);
2047 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
2048 }
2049 spin_unlock_irqrestore(&gsm->control_lock, flags);
2050}
2051
2052/**
2053 * gsm_control_send - send a control frame on DLCI 0
2054 * @gsm: the GSM channel
2055 * @command: command to send including CR bit
2056 * @data: bytes of data (must be kmalloced)
2057 * @clen: length of the block to send
2058 *
2059 * Queue and dispatch a control command. Only one command can be
2060 * active at a time. In theory more can be outstanding but the matching
2061 * gets really complicated so for now stick to one outstanding.
2062 */
2063
2064static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
2065 unsigned int command, u8 *data, int clen)
2066{
2067 struct gsm_control *ctrl = kzalloc_obj(struct gsm_control, GFP_ATOMIC);
2068 unsigned long flags;
2069 if (ctrl == NULL)
2070 return NULL;
2071retry:
2072 wait_event(gsm->event, gsm->pending_cmd == NULL);
2073 spin_lock_irqsave(&gsm->control_lock, flags);
2074 if (gsm->pending_cmd != NULL) {
2075 spin_unlock_irqrestore(&gsm->control_lock, flags);
2076 goto retry;
2077 }
2078 ctrl->cmd = command;
2079 ctrl->data = data;
2080 ctrl->len = clen;
2081 gsm->pending_cmd = ctrl;
2082
2083 /* If DLCI0 is in ADM mode skip retries, it won't respond */
2084 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
2085 gsm->cretries = 0;
2086 else
2087 gsm->cretries = gsm->n2;
2088
2089 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
2090 gsm_control_transmit(gsm, ctrl);
2091 spin_unlock_irqrestore(&gsm->control_lock, flags);
2092 return ctrl;
2093}
2094
2095/**
2096 * gsm_control_wait - wait for a control to finish
2097 * @gsm: GSM mux
2098 * @control: control we are waiting on
2099 *
2100 * Waits for the control to complete or time out. Frees any used
2101 * resources and returns 0 for success, or an error if the remote
2102 * rejected or ignored the request.
2103 */
2104
2105static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
2106{
2107 int err;
2108 wait_event(gsm->event, control->done == 1);
2109 err = control->error;
2110 kfree(control);
2111 return err;
2112}
2113
2114
2115/*
2116 * DLCI level handling: Needs krefs
2117 */
2118
2119/*
2120 * State transitions and timers
2121 */
2122
2123/**
2124 * gsm_dlci_close - a DLCI has closed
2125 * @dlci: DLCI that closed
2126 *
2127 * Perform processing when moving a DLCI into closed state. If there
2128 * is an attached tty this is hung up
2129 */
2130
2131static void gsm_dlci_close(struct gsm_dlci *dlci)
2132{
2133 timer_delete(&dlci->t1);
2134 if (debug & DBG_ERRORS)
2135 pr_debug("DLCI %d goes closed.\n", dlci->addr);
2136 dlci->state = DLCI_CLOSED;
2137 /* Prevent us from sending data before the link is up again */
2138 dlci->constipated = true;
2139 if (dlci->addr != 0) {
2140 tty_port_tty_hangup(&dlci->port, false);
2141 gsm_dlci_clear_queues(dlci->gsm, dlci);
2142 /* Ensure that gsmtty_open() can return. */
2143 tty_port_set_initialized(&dlci->port, false);
2144 wake_up_interruptible(&dlci->port.open_wait);
2145 } else {
2146 timer_delete(&dlci->gsm->ka_timer);
2147 dlci->gsm->dead = true;
2148 }
2149 /* A DLCI 0 close is a MUX termination so we need to kick that
2150 back to userspace somehow */
2151 gsm_dlci_data_kick(dlci);
2152 wake_up_all(&dlci->gsm->event);
2153}
2154
2155/**
2156 * gsm_dlci_open - a DLCI has opened
2157 * @dlci: DLCI that opened
2158 *
2159 * Perform processing when moving a DLCI into open state.
2160 */
2161
2162static void gsm_dlci_open(struct gsm_dlci *dlci)
2163{
2164 struct gsm_mux *gsm = dlci->gsm;
2165
2166 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
2167 open -> open */
2168 timer_delete(&dlci->t1);
2169 /* This will let a tty open continue */
2170 dlci->state = DLCI_OPEN;
2171 dlci->constipated = false;
2172 if (debug & DBG_ERRORS)
2173 pr_debug("DLCI %d goes open.\n", dlci->addr);
2174 /* Send current modem state */
2175 if (dlci->addr) {
2176 gsm_modem_update(dlci, 0, false);
2177 } else {
2178 /* Start keep-alive control */
2179 gsm->ka_num = 0;
2180 gsm->ka_retries = -1;
2181 mod_timer(&gsm->ka_timer,
2182 jiffies + gsm->keep_alive * HZ / 100);
2183 }
2184 gsm_dlci_data_kick(dlci);
2185 wake_up(&dlci->gsm->event);
2186}
2187
2188/**
2189 * gsm_dlci_negotiate - start parameter negotiation
2190 * @dlci: DLCI to open
2191 *
2192 * Starts the parameter negotiation for the new DLCI. This needs to be done
2193 * before the DLCI initialized the channel via SABM.
2194 */
2195static int gsm_dlci_negotiate(struct gsm_dlci *dlci)
2196{
2197 struct gsm_mux *gsm = dlci->gsm;
2198 struct gsm_dlci_param_bits params;
2199 int ret;
2200
2201 ret = gsm_encode_params(dlci, &params);
2202 if (ret != 0)
2203 return ret;
2204
2205 /* We cannot asynchronous wait for the command response with
2206 * gsm_command() and gsm_control_wait() at this point.
2207 */
2208 ret = gsm_control_command(gsm, CMD_PN, (const u8 *)&params,
2209 sizeof(params));
2210
2211 return ret;
2212}
2213
2214/**
2215 * gsm_dlci_t1 - T1 timer expiry
2216 * @t: timer contained in the DLCI that opened
2217 *
2218 * The T1 timer handles retransmits of control frames (essentially of
2219 * SABM and DISC). We resend the command until the retry count runs out
2220 * in which case an opening port goes back to closed and a closing port
2221 * is simply put into closed state (any further frames from the other
2222 * end will get a DM response)
2223 *
2224 * Some control dlci can stay in ADM mode with other dlci working just
2225 * fine. In that case we can just keep the control dlci open after the
2226 * DLCI_OPENING receives DM.
2227 */
2228
2229static void gsm_dlci_t1(struct timer_list *t)
2230{
2231 struct gsm_dlci *dlci = timer_container_of(dlci, t, t1);
2232 struct gsm_mux *gsm = dlci->gsm;
2233
2234 switch (dlci->state) {
2235 case DLCI_CONFIGURE:
2236 if (dlci->retries && gsm_dlci_negotiate(dlci) == 0) {
2237 dlci->retries--;
2238 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2239 } else {
2240 gsm->open_error++;
2241 gsm_dlci_begin_close(dlci); /* prevent half open link */
2242 }
2243 break;
2244 case DLCI_OPENING:
2245 if (!dlci->addr && gsm->control == (DM | PF)) {
2246 if (debug & DBG_ERRORS)
2247 pr_info("DLCI 0 opening in ADM mode.\n");
2248 dlci->mode = DLCI_MODE_ADM;
2249 gsm_dlci_open(dlci);
2250 } else if (dlci->retries) {
2251 if (!dlci->addr || !gsm->dlci[0] ||
2252 gsm->dlci[0]->state != DLCI_OPENING) {
2253 dlci->retries--;
2254 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
2255 }
2256
2257 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2258 } else {
2259 gsm->open_error++;
2260 gsm_dlci_begin_close(dlci); /* prevent half open link */
2261 }
2262
2263 break;
2264 case DLCI_CLOSING:
2265 if (dlci->retries) {
2266 dlci->retries--;
2267 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
2268 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2269 } else
2270 gsm_dlci_close(dlci);
2271 break;
2272 default:
2273 pr_debug("%s: unhandled state: %d\n", __func__, dlci->state);
2274 break;
2275 }
2276}
2277
2278/**
2279 * gsm_dlci_begin_open - start channel open procedure
2280 * @dlci: DLCI to open
2281 *
2282 * Commence opening a DLCI from the Linux side. We issue SABM messages
2283 * to the modem which should then reply with a UA or ADM, at which point
2284 * we will move into open state. Opening is done asynchronously with retry
2285 * running off timers and the responses.
2286 * Parameter negotiation is performed before SABM if required.
2287 */
2288
2289static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
2290{
2291 struct gsm_mux *gsm = dlci ? dlci->gsm : NULL;
2292 bool need_pn = false;
2293
2294 if (!gsm)
2295 return;
2296
2297 if (dlci->addr != 0) {
2298 if (gsm->adaption != 1 || gsm->adaption != dlci->adaption)
2299 need_pn = true;
2300 if (dlci->prio != (roundup(dlci->addr + 1, 8) - 1))
2301 need_pn = true;
2302 if (gsm->ftype != dlci->ftype)
2303 need_pn = true;
2304 }
2305
2306 switch (dlci->state) {
2307 case DLCI_CLOSED:
2308 case DLCI_WAITING_CONFIG:
2309 case DLCI_CLOSING:
2310 dlci->retries = gsm->n2;
2311 if (!need_pn) {
2312 dlci->state = DLCI_OPENING;
2313 if (!dlci->addr || !gsm->dlci[0] ||
2314 gsm->dlci[0]->state != DLCI_OPENING)
2315 gsm_command(gsm, dlci->addr, SABM|PF);
2316 } else {
2317 /* Configure DLCI before setup */
2318 dlci->state = DLCI_CONFIGURE;
2319 if (gsm_dlci_negotiate(dlci) != 0) {
2320 gsm_dlci_close(dlci);
2321 return;
2322 }
2323 }
2324 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2325 break;
2326 default:
2327 break;
2328 }
2329}
2330
2331/**
2332 * gsm_dlci_set_opening - change state to opening
2333 * @dlci: DLCI to open
2334 *
2335 * Change internal state to wait for DLCI open from initiator side.
2336 * We set off timers and responses upon reception of an SABM.
2337 */
2338static void gsm_dlci_set_opening(struct gsm_dlci *dlci)
2339{
2340 switch (dlci->state) {
2341 case DLCI_CLOSED:
2342 case DLCI_WAITING_CONFIG:
2343 case DLCI_CLOSING:
2344 dlci->state = DLCI_OPENING;
2345 break;
2346 default:
2347 break;
2348 }
2349}
2350
2351/**
2352 * gsm_dlci_set_wait_config - wait for channel configuration
2353 * @dlci: DLCI to configure
2354 *
2355 * Wait for a DLCI configuration from the application.
2356 */
2357static void gsm_dlci_set_wait_config(struct gsm_dlci *dlci)
2358{
2359 switch (dlci->state) {
2360 case DLCI_CLOSED:
2361 case DLCI_CLOSING:
2362 dlci->state = DLCI_WAITING_CONFIG;
2363 break;
2364 default:
2365 break;
2366 }
2367}
2368
2369/**
2370 * gsm_dlci_begin_close - start channel open procedure
2371 * @dlci: DLCI to open
2372 *
2373 * Commence closing a DLCI from the Linux side. We issue DISC messages
2374 * to the modem which should then reply with a UA, at which point we
2375 * will move into closed state. Closing is done asynchronously with retry
2376 * off timers. We may also receive a DM reply from the other end which
2377 * indicates the channel was already closed.
2378 */
2379
2380static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
2381{
2382 struct gsm_mux *gsm = dlci->gsm;
2383 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
2384 return;
2385 dlci->retries = gsm->n2;
2386 dlci->state = DLCI_CLOSING;
2387 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
2388 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2389 wake_up_interruptible(&gsm->event);
2390}
2391
2392/**
2393 * gsm_dlci_data - data arrived
2394 * @dlci: channel
2395 * @data: block of bytes received
2396 * @clen: length of received block
2397 *
2398 * A UI or UIH frame has arrived which contains data for a channel
2399 * other than the control channel. If the relevant virtual tty is
2400 * open we shovel the bits down it, if not we drop them.
2401 */
2402
2403static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
2404{
2405 /* krefs .. */
2406 struct tty_port *port = &dlci->port;
2407 struct tty_struct *tty;
2408 unsigned int modem = 0;
2409 int len;
2410
2411 if (debug & DBG_TTY)
2412 pr_debug("%d bytes for tty\n", clen);
2413 switch (dlci->adaption) {
2414 /* Unsupported types */
2415 case 4: /* Packetised interruptible data */
2416 break;
2417 case 3: /* Packetised uininterruptible voice/data */
2418 break;
2419 case 2: /* Asynchronous serial with line state in each frame */
2420 len = gsm_read_ea_val(&modem, data, clen);
2421 if (len < 1)
2422 return;
2423 tty = tty_port_tty_get(port);
2424 if (tty) {
2425 gsm_process_modem(tty, dlci, modem, len);
2426 tty_wakeup(tty);
2427 tty_kref_put(tty);
2428 }
2429 /* Skip processed modem data */
2430 data += len;
2431 clen -= len;
2432 fallthrough;
2433 case 1: /* Line state will go via DLCI 0 controls only */
2434 default:
2435 tty_insert_flip_string(port, data, clen);
2436 tty_flip_buffer_push(port);
2437 }
2438}
2439
2440/**
2441 * gsm_dlci_command - data arrived on control channel
2442 * @dlci: channel
2443 * @data: block of bytes received
2444 * @len: length of received block
2445 *
2446 * A UI or UIH frame has arrived which contains data for DLCI 0 the
2447 * control channel. This should contain a command EA followed by
2448 * control data bytes. The command EA contains a command/response bit
2449 * and we divide up the work accordingly.
2450 */
2451
2452static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
2453{
2454 /* See what command is involved */
2455 unsigned int command = 0;
2456 unsigned int clen = 0;
2457 unsigned int dlen;
2458
2459 /* read the command */
2460 dlen = gsm_read_ea_val(&command, data, len);
2461 len -= dlen;
2462 data += dlen;
2463
2464 /* read any control data */
2465 dlen = gsm_read_ea_val(&clen, data, len);
2466 len -= dlen;
2467 data += dlen;
2468
2469 /* Malformed command? */
2470 if (clen > len) {
2471 dlci->gsm->malformed++;
2472 return;
2473 }
2474
2475 if (command & 1)
2476 gsm_control_message(dlci->gsm, command, data, clen);
2477 else
2478 gsm_control_response(dlci->gsm, command, data, clen);
2479}
2480
2481/**
2482 * gsm_kick_timer - transmit if possible
2483 * @t: timer contained in our gsm object
2484 *
2485 * Transmit data from DLCIs if the queue is empty. We can't rely on
2486 * a tty wakeup except when we filled the pipe so we need to fire off
2487 * new data ourselves in other cases.
2488 */
2489static void gsm_kick_timer(struct timer_list *t)
2490{
2491 struct gsm_mux *gsm = timer_container_of(gsm, t, kick_timer);
2492 unsigned long flags;
2493 int sent = 0;
2494
2495 spin_lock_irqsave(&gsm->tx_lock, flags);
2496 /* If we have nothing running then we need to fire up */
2497 if (gsm->tx_bytes < TX_THRESH_LO)
2498 sent = gsm_dlci_data_sweep(gsm);
2499 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2500
2501 if (sent && debug & DBG_DATA)
2502 pr_info("%s TX queue stalled\n", __func__);
2503}
2504
2505/**
2506 * gsm_dlci_copy_config_values - copy DLCI configuration
2507 * @dlci: source DLCI
2508 * @dc: configuration structure to fill
2509 */
2510static void gsm_dlci_copy_config_values(struct gsm_dlci *dlci, struct gsm_dlci_config *dc)
2511{
2512 memset(dc, 0, sizeof(*dc));
2513 dc->channel = (u32)dlci->addr;
2514 dc->adaption = (u32)dlci->adaption;
2515 dc->mtu = (u32)dlci->mtu;
2516 dc->priority = (u32)dlci->prio;
2517 if (dlci->ftype == UIH)
2518 dc->i = 1;
2519 else
2520 dc->i = 2;
2521 dc->k = (u32)dlci->k;
2522}
2523
2524/**
2525 * gsm_dlci_config - configure DLCI from configuration
2526 * @dlci: DLCI to configure
2527 * @dc: DLCI configuration
2528 * @open: open DLCI after configuration?
2529 */
2530static int gsm_dlci_config(struct gsm_dlci *dlci, struct gsm_dlci_config *dc, int open)
2531{
2532 struct gsm_mux *gsm;
2533 bool need_restart = false;
2534 bool need_open = false;
2535 unsigned int i;
2536
2537 /*
2538 * Check that userspace doesn't put stuff in here to prevent breakages
2539 * in the future.
2540 */
2541 for (i = 0; i < ARRAY_SIZE(dc->reserved); i++)
2542 if (dc->reserved[i])
2543 return -EINVAL;
2544
2545 if (!dlci)
2546 return -EINVAL;
2547 gsm = dlci->gsm;
2548
2549 /* Stuff we don't support yet - I frame transport */
2550 if (dc->adaption != 1 && dc->adaption != 2)
2551 return -EOPNOTSUPP;
2552 if (dc->mtu > MAX_MTU || dc->mtu < MIN_MTU || dc->mtu > gsm->mru)
2553 return -EINVAL;
2554 if (dc->priority >= 64)
2555 return -EINVAL;
2556 if (dc->i == 0 || dc->i > 2) /* UIH and UI only */
2557 return -EINVAL;
2558 if (dc->k > 7)
2559 return -EINVAL;
2560 if (dc->flags & ~GSM_FL_RESTART) /* allow future extensions */
2561 return -EINVAL;
2562
2563 /*
2564 * See what is needed for reconfiguration
2565 */
2566 /* Framing fields */
2567 if (dc->adaption != dlci->adaption)
2568 need_restart = true;
2569 if (dc->mtu != dlci->mtu)
2570 need_restart = true;
2571 if (dc->i != dlci->ftype)
2572 need_restart = true;
2573 /* Requires care */
2574 if (dc->priority != dlci->prio)
2575 need_restart = true;
2576 if (dc->flags & GSM_FL_RESTART)
2577 need_restart = true;
2578
2579 if ((open && gsm->wait_config) || need_restart)
2580 need_open = true;
2581 if (dlci->state == DLCI_WAITING_CONFIG) {
2582 need_restart = false;
2583 need_open = true;
2584 }
2585
2586 /*
2587 * Close down what is needed, restart and initiate the new
2588 * configuration.
2589 */
2590 if (need_restart) {
2591 gsm_dlci_begin_close(dlci);
2592 wait_event_interruptible(gsm->event, dlci->state == DLCI_CLOSED);
2593 if (signal_pending(current))
2594 return -EINTR;
2595 }
2596 /*
2597 * Setup the new configuration values
2598 */
2599 dlci->adaption = (int)dc->adaption;
2600
2601 if (dc->mtu)
2602 dlci->mtu = (unsigned int)dc->mtu;
2603 else
2604 dlci->mtu = gsm->mtu;
2605
2606 if (dc->priority)
2607 dlci->prio = (u8)dc->priority;
2608 else
2609 dlci->prio = roundup(dlci->addr + 1, 8) - 1;
2610
2611 if (dc->i == 1)
2612 dlci->ftype = UIH;
2613 else if (dc->i == 2)
2614 dlci->ftype = UI;
2615
2616 if (dc->k)
2617 dlci->k = (u8)dc->k;
2618 else
2619 dlci->k = gsm->k;
2620
2621 if (need_open) {
2622 if (gsm->initiator)
2623 gsm_dlci_begin_open(dlci);
2624 else
2625 gsm_dlci_set_opening(dlci);
2626 }
2627
2628 return 0;
2629}
2630
2631/*
2632 * Allocate/Free DLCI channels
2633 */
2634
2635/**
2636 * gsm_dlci_alloc - allocate a DLCI
2637 * @gsm: GSM mux
2638 * @addr: address of the DLCI
2639 *
2640 * Allocate and install a new DLCI object into the GSM mux.
2641 *
2642 * FIXME: review locking races
2643 */
2644
2645static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
2646{
2647 struct gsm_dlci *dlci = kzalloc_obj(struct gsm_dlci, GFP_ATOMIC);
2648 if (dlci == NULL)
2649 return NULL;
2650 spin_lock_init(&dlci->lock);
2651 mutex_init(&dlci->mutex);
2652 if (kfifo_alloc(&dlci->fifo, TX_SIZE, GFP_KERNEL) < 0) {
2653 kfree(dlci);
2654 return NULL;
2655 }
2656
2657 skb_queue_head_init(&dlci->skb_list);
2658 timer_setup(&dlci->t1, gsm_dlci_t1, 0);
2659 tty_port_init(&dlci->port);
2660 dlci->port.ops = &gsm_port_ops;
2661 dlci->gsm = gsm;
2662 dlci->addr = addr;
2663 dlci->adaption = gsm->adaption;
2664 dlci->mtu = gsm->mtu;
2665 if (addr == 0)
2666 dlci->prio = 0;
2667 else
2668 dlci->prio = roundup(addr + 1, 8) - 1;
2669 dlci->ftype = gsm->ftype;
2670 dlci->k = gsm->k;
2671 dlci->state = DLCI_CLOSED;
2672 if (addr) {
2673 dlci->data = gsm_dlci_data;
2674 /* Prevent us from sending data before the link is up */
2675 dlci->constipated = true;
2676 } else {
2677 dlci->data = gsm_dlci_command;
2678 }
2679 gsm->dlci[addr] = dlci;
2680 return dlci;
2681}
2682
2683/**
2684 * gsm_dlci_free - free DLCI
2685 * @port: tty port for DLCI to free
2686 *
2687 * Free up a DLCI.
2688 *
2689 * Can sleep.
2690 */
2691static void gsm_dlci_free(struct tty_port *port)
2692{
2693 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2694
2695 timer_shutdown_sync(&dlci->t1);
2696 dlci->gsm->dlci[dlci->addr] = NULL;
2697 kfifo_free(&dlci->fifo);
2698 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
2699 dev_kfree_skb(dlci->skb);
2700 kfree(dlci);
2701}
2702
2703static inline void dlci_get(struct gsm_dlci *dlci)
2704{
2705 tty_port_get(&dlci->port);
2706}
2707
2708static inline void dlci_put(struct gsm_dlci *dlci)
2709{
2710 tty_port_put(&dlci->port);
2711}
2712
2713static void gsm_destroy_network(struct gsm_dlci *dlci);
2714
2715/**
2716 * gsm_dlci_release - release DLCI
2717 * @dlci: DLCI to destroy
2718 *
2719 * Release a DLCI. Actual free is deferred until either
2720 * mux is closed or tty is closed - whichever is last.
2721 *
2722 * Can sleep.
2723 */
2724static void gsm_dlci_release(struct gsm_dlci *dlci)
2725{
2726 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
2727 if (tty) {
2728 mutex_lock(&dlci->mutex);
2729 gsm_destroy_network(dlci);
2730 mutex_unlock(&dlci->mutex);
2731
2732 /* We cannot use tty_hangup() because in tty_kref_put() the tty
2733 * driver assumes that the hangup queue is free and reuses it to
2734 * queue release_one_tty() -> NULL pointer panic in
2735 * process_one_work().
2736 */
2737 tty_vhangup(tty);
2738
2739 tty_port_tty_set(&dlci->port, NULL);
2740 tty_kref_put(tty);
2741 }
2742 dlci->state = DLCI_CLOSED;
2743 dlci_put(dlci);
2744}
2745
2746/*
2747 * LAPBish link layer logic
2748 */
2749
2750/**
2751 * gsm_queue - a GSM frame is ready to process
2752 * @gsm: pointer to our gsm mux
2753 *
2754 * At this point in time a frame has arrived and been demangled from
2755 * the line encoding. All the differences between the encodings have
2756 * been handled below us and the frame is unpacked into the structures.
2757 * The fcs holds the header FCS but any data FCS must be added here.
2758 */
2759
2760static void gsm_queue(struct gsm_mux *gsm)
2761{
2762 struct gsm_dlci *dlci;
2763 u8 cr;
2764 int address;
2765
2766 if (gsm->fcs != GOOD_FCS) {
2767 gsm->bad_fcs++;
2768 if (debug & DBG_DATA)
2769 pr_debug("BAD FCS %02x\n", gsm->fcs);
2770 return;
2771 }
2772 address = gsm->address >> 1;
2773 if (address >= NUM_DLCI)
2774 goto invalid;
2775
2776 cr = gsm->address & 1; /* C/R bit */
2777 cr ^= gsm->initiator ? 0 : 1; /* Flip so 1 always means command */
2778
2779 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
2780
2781 dlci = gsm->dlci[address];
2782
2783 switch (gsm->control) {
2784 case SABM|PF:
2785 if (cr == 1) {
2786 gsm->open_error++;
2787 goto invalid;
2788 }
2789 if (dlci == NULL)
2790 dlci = gsm_dlci_alloc(gsm, address);
2791 if (dlci == NULL) {
2792 gsm->open_error++;
2793 return;
2794 }
2795 if (dlci->dead)
2796 gsm_response(gsm, address, DM|PF);
2797 else {
2798 gsm_response(gsm, address, UA|PF);
2799 gsm_dlci_open(dlci);
2800 }
2801 break;
2802 case DISC|PF:
2803 if (cr == 1)
2804 goto invalid;
2805 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
2806 gsm_response(gsm, address, DM|PF);
2807 return;
2808 }
2809 /* Real close complete */
2810 gsm_response(gsm, address, UA|PF);
2811 gsm_dlci_close(dlci);
2812 break;
2813 case UA|PF:
2814 if (cr == 0 || dlci == NULL)
2815 break;
2816 switch (dlci->state) {
2817 case DLCI_CLOSING:
2818 gsm_dlci_close(dlci);
2819 break;
2820 case DLCI_OPENING:
2821 gsm_dlci_open(dlci);
2822 break;
2823 default:
2824 pr_debug("%s: unhandled state: %d\n", __func__,
2825 dlci->state);
2826 break;
2827 }
2828 break;
2829 case DM: /* DM can be valid unsolicited */
2830 case DM|PF:
2831 if (cr)
2832 goto invalid;
2833 if (dlci == NULL)
2834 return;
2835 gsm_dlci_close(dlci);
2836 break;
2837 case UI:
2838 case UI|PF:
2839 case UIH:
2840 case UIH|PF:
2841 if (dlci == NULL || dlci->state != DLCI_OPEN) {
2842 gsm_response(gsm, address, DM|PF);
2843 return;
2844 }
2845 dlci->data(dlci, gsm->buf, gsm->len);
2846 break;
2847 default:
2848 goto invalid;
2849 }
2850 return;
2851invalid:
2852 gsm->malformed++;
2853 return;
2854}
2855
2856/**
2857 * gsm0_receive_state_check_and_fix - check and correct receive state
2858 * @gsm: gsm data for this ldisc instance
2859 *
2860 * Ensures that the current receive state is valid for basic option mode.
2861 */
2862
2863static void gsm0_receive_state_check_and_fix(struct gsm_mux *gsm)
2864{
2865 switch (gsm->state) {
2866 case GSM_SEARCH:
2867 case GSM0_ADDRESS:
2868 case GSM0_CONTROL:
2869 case GSM0_LEN0:
2870 case GSM0_LEN1:
2871 case GSM0_DATA:
2872 case GSM0_FCS:
2873 case GSM0_SSOF:
2874 break;
2875 default:
2876 gsm->state = GSM_SEARCH;
2877 break;
2878 }
2879}
2880
2881/**
2882 * gsm0_receive - perform processing for non-transparency
2883 * @gsm: gsm data for this ldisc instance
2884 * @c: character
2885 *
2886 * Receive bytes in gsm mode 0
2887 */
2888
2889static void gsm0_receive(struct gsm_mux *gsm, u8 c)
2890{
2891 unsigned int len;
2892
2893 gsm0_receive_state_check_and_fix(gsm);
2894 switch (gsm->state) {
2895 case GSM_SEARCH: /* SOF marker */
2896 if (c == GSM0_SOF) {
2897 gsm->state = GSM0_ADDRESS;
2898 gsm->address = 0;
2899 gsm->len = 0;
2900 gsm->fcs = INIT_FCS;
2901 }
2902 break;
2903 case GSM0_ADDRESS: /* Address EA */
2904 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2905 if (gsm_read_ea(&gsm->address, c))
2906 gsm->state = GSM0_CONTROL;
2907 break;
2908 case GSM0_CONTROL: /* Control Byte */
2909 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2910 gsm->control = c;
2911 gsm->state = GSM0_LEN0;
2912 break;
2913 case GSM0_LEN0: /* Length EA */
2914 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2915 if (gsm_read_ea(&gsm->len, c)) {
2916 if (gsm->len > gsm->mru) {
2917 gsm->bad_size++;
2918 gsm->state = GSM_SEARCH;
2919 break;
2920 }
2921 gsm->count = 0;
2922 if (!gsm->len)
2923 gsm->state = GSM0_FCS;
2924 else
2925 gsm->state = GSM0_DATA;
2926 break;
2927 }
2928 gsm->state = GSM0_LEN1;
2929 break;
2930 case GSM0_LEN1:
2931 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2932 len = c;
2933 gsm->len |= len << 7;
2934 if (gsm->len > gsm->mru) {
2935 gsm->bad_size++;
2936 gsm->state = GSM_SEARCH;
2937 break;
2938 }
2939 gsm->count = 0;
2940 if (!gsm->len)
2941 gsm->state = GSM0_FCS;
2942 else
2943 gsm->state = GSM0_DATA;
2944 break;
2945 case GSM0_DATA: /* Data */
2946 gsm->buf[gsm->count++] = c;
2947 if (gsm->count >= MAX_MRU) {
2948 gsm->bad_size++;
2949 gsm->state = GSM_SEARCH;
2950 } else if (gsm->count >= gsm->len) {
2951 /* Calculate final FCS for UI frames over all data */
2952 if ((gsm->control & ~PF) != UIH) {
2953 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
2954 gsm->count);
2955 }
2956 gsm->state = GSM0_FCS;
2957 }
2958 break;
2959 case GSM0_FCS: /* FCS follows the packet */
2960 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2961 gsm->state = GSM0_SSOF;
2962 break;
2963 case GSM0_SSOF:
2964 gsm->state = GSM_SEARCH;
2965 if (c == GSM0_SOF)
2966 gsm_queue(gsm);
2967 else
2968 gsm->bad_size++;
2969 break;
2970 default:
2971 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
2972 break;
2973 }
2974}
2975
2976/**
2977 * gsm1_receive_state_check_and_fix - check and correct receive state
2978 * @gsm: gsm data for this ldisc instance
2979 *
2980 * Ensures that the current receive state is valid for advanced option mode.
2981 */
2982
2983static void gsm1_receive_state_check_and_fix(struct gsm_mux *gsm)
2984{
2985 switch (gsm->state) {
2986 case GSM_SEARCH:
2987 case GSM1_START:
2988 case GSM1_ADDRESS:
2989 case GSM1_CONTROL:
2990 case GSM1_DATA:
2991 case GSM1_OVERRUN:
2992 break;
2993 default:
2994 gsm->state = GSM_SEARCH;
2995 break;
2996 }
2997}
2998
2999/**
3000 * gsm1_receive - perform processing for non-transparency
3001 * @gsm: gsm data for this ldisc instance
3002 * @c: character
3003 *
3004 * Receive bytes in mode 1 (Advanced option)
3005 */
3006
3007static void gsm1_receive(struct gsm_mux *gsm, u8 c)
3008{
3009 gsm1_receive_state_check_and_fix(gsm);
3010 /* handle XON/XOFF */
3011 if ((c & ISO_IEC_646_MASK) == XON) {
3012 gsm->constipated = true;
3013 return;
3014 } else if ((c & ISO_IEC_646_MASK) == XOFF) {
3015 gsm->constipated = false;
3016 /* Kick the link in case it is idling */
3017 gsmld_write_trigger(gsm);
3018 return;
3019 }
3020 if (c == GSM1_SOF) {
3021 /* EOF is only valid in frame if we have got to the data state */
3022 if (gsm->state == GSM1_DATA) {
3023 if (gsm->count < 1) {
3024 /* Missing FSC */
3025 gsm->malformed++;
3026 gsm->state = GSM1_START;
3027 return;
3028 }
3029 /* Remove the FCS from data */
3030 gsm->count--;
3031 if ((gsm->control & ~PF) != UIH) {
3032 /* Calculate final FCS for UI frames over all
3033 * data but FCS
3034 */
3035 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
3036 gsm->count);
3037 }
3038 /* Add the FCS itself to test against GOOD_FCS */
3039 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
3040 gsm->len = gsm->count;
3041 gsm_queue(gsm);
3042 gsm->state = GSM1_START;
3043 return;
3044 }
3045 /* Any partial frame was a runt so go back to start */
3046 if (gsm->state != GSM1_START) {
3047 if (gsm->state != GSM_SEARCH)
3048 gsm->malformed++;
3049 gsm->state = GSM1_START;
3050 }
3051 /* A SOF in GSM_START means we are still reading idling or
3052 framing bytes */
3053 return;
3054 }
3055
3056 if (c == GSM1_ESCAPE) {
3057 gsm->escape = true;
3058 return;
3059 }
3060
3061 /* Only an unescaped SOF gets us out of GSM search */
3062 if (gsm->state == GSM_SEARCH)
3063 return;
3064
3065 if (gsm->escape) {
3066 c ^= GSM1_ESCAPE_BITS;
3067 gsm->escape = false;
3068 }
3069 switch (gsm->state) {
3070 case GSM1_START: /* First byte after SOF */
3071 gsm->address = 0;
3072 gsm->state = GSM1_ADDRESS;
3073 gsm->fcs = INIT_FCS;
3074 fallthrough;
3075 case GSM1_ADDRESS: /* Address continuation */
3076 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
3077 if (gsm_read_ea(&gsm->address, c))
3078 gsm->state = GSM1_CONTROL;
3079 break;
3080 case GSM1_CONTROL: /* Control Byte */
3081 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
3082 gsm->control = c;
3083 gsm->count = 0;
3084 gsm->state = GSM1_DATA;
3085 break;
3086 case GSM1_DATA: /* Data */
3087 if (gsm->count > gsm->mru || gsm->count > MAX_MRU) { /* Allow one for the FCS */
3088 gsm->state = GSM1_OVERRUN;
3089 gsm->bad_size++;
3090 } else
3091 gsm->buf[gsm->count++] = c;
3092 break;
3093 case GSM1_OVERRUN: /* Over-long - eg a dropped SOF */
3094 break;
3095 default:
3096 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
3097 break;
3098 }
3099}
3100
3101/**
3102 * gsm_error - handle tty error
3103 * @gsm: ldisc data
3104 *
3105 * Handle an error in the receipt of data for a frame. Currently we just
3106 * go back to hunting for a SOF.
3107 *
3108 * FIXME: better diagnostics ?
3109 */
3110
3111static void gsm_error(struct gsm_mux *gsm)
3112{
3113 gsm->state = GSM_SEARCH;
3114 gsm->io_error++;
3115}
3116
3117/**
3118 * gsm_cleanup_mux - generic GSM protocol cleanup
3119 * @gsm: our mux
3120 * @disc: disconnect link?
3121 *
3122 * Clean up the bits of the mux which are the same for all framing
3123 * protocols. Remove the mux from the mux table, stop all the timers
3124 * and then shut down each device hanging up the channels as we go.
3125 */
3126
3127static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc)
3128{
3129 int i;
3130 struct gsm_dlci *dlci;
3131 struct gsm_msg *txq, *ntxq;
3132
3133 gsm->dead = true;
3134 mutex_lock(&gsm->mutex);
3135
3136 dlci = gsm->dlci[0];
3137 if (dlci) {
3138 if (disc && dlci->state != DLCI_CLOSED) {
3139 gsm_dlci_begin_close(dlci);
3140 wait_event(gsm->event, dlci->state == DLCI_CLOSED);
3141 }
3142 dlci->dead = true;
3143 }
3144
3145 /* Finish outstanding timers, making sure they are done */
3146 timer_delete_sync(&gsm->kick_timer);
3147 timer_delete_sync(&gsm->t2_timer);
3148 timer_delete_sync(&gsm->ka_timer);
3149
3150 /* Finish writing to ldisc */
3151 flush_work(&gsm->tx_work);
3152
3153 /* Free up any link layer users and finally the control channel */
3154 if (gsm->has_devices) {
3155 gsm_unregister_devices(gsm_tty_driver, gsm->num);
3156 gsm->has_devices = false;
3157 }
3158 for (i = NUM_DLCI - 1; i >= 0; i--)
3159 if (gsm->dlci[i])
3160 gsm_dlci_release(gsm->dlci[i]);
3161 mutex_unlock(&gsm->mutex);
3162 /* Now wipe the queues */
3163 tty_ldisc_flush(gsm->tty);
3164
3165 guard(spinlock_irqsave)(&gsm->tx_lock);
3166 list_for_each_entry_safe(txq, ntxq, &gsm->tx_ctrl_list, list)
3167 kfree(txq);
3168 INIT_LIST_HEAD(&gsm->tx_ctrl_list);
3169 list_for_each_entry_safe(txq, ntxq, &gsm->tx_data_list, list)
3170 kfree(txq);
3171 INIT_LIST_HEAD(&gsm->tx_data_list);
3172}
3173
3174/**
3175 * gsm_activate_mux - generic GSM setup
3176 * @gsm: our mux
3177 *
3178 * Set up the bits of the mux which are the same for all framing
3179 * protocols. Add the mux to the mux table so it can be opened and
3180 * finally kick off connecting to DLCI 0 on the modem.
3181 */
3182
3183static int gsm_activate_mux(struct gsm_mux *gsm)
3184{
3185 struct gsm_dlci *dlci;
3186 int ret;
3187
3188 dlci = gsm_dlci_alloc(gsm, 0);
3189 if (dlci == NULL)
3190 return -ENOMEM;
3191
3192 if (gsm->encoding == GSM_BASIC_OPT)
3193 gsm->receive = gsm0_receive;
3194 else
3195 gsm->receive = gsm1_receive;
3196
3197 ret = gsm_register_devices(gsm_tty_driver, gsm->num);
3198 if (ret)
3199 return ret;
3200
3201 gsm->has_devices = true;
3202 gsm->dead = false; /* Tty opens are now permissible */
3203 return 0;
3204}
3205
3206/**
3207 * gsm_free_mux - free up a mux
3208 * @gsm: mux to free
3209 *
3210 * Dispose of allocated resources for a dead mux
3211 */
3212static void gsm_free_mux(struct gsm_mux *gsm)
3213{
3214 int i;
3215
3216 for (i = 0; i < MAX_MUX; i++) {
3217 if (gsm == gsm_mux[i]) {
3218 gsm_mux[i] = NULL;
3219 break;
3220 }
3221 }
3222 mutex_destroy(&gsm->mutex);
3223 kfree(gsm->txframe);
3224 kfree(gsm->buf);
3225 kfree(gsm);
3226}
3227
3228/**
3229 * gsm_free_muxr - free up a mux
3230 * @ref: kreference to the mux to free
3231 *
3232 * Dispose of allocated resources for a dead mux
3233 */
3234static void gsm_free_muxr(struct kref *ref)
3235{
3236 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
3237 gsm_free_mux(gsm);
3238}
3239
3240static inline void mux_get(struct gsm_mux *gsm)
3241{
3242 unsigned long flags;
3243
3244 spin_lock_irqsave(&gsm_mux_lock, flags);
3245 kref_get(&gsm->ref);
3246 spin_unlock_irqrestore(&gsm_mux_lock, flags);
3247}
3248
3249static inline void mux_put(struct gsm_mux *gsm)
3250{
3251 unsigned long flags;
3252
3253 spin_lock_irqsave(&gsm_mux_lock, flags);
3254 kref_put(&gsm->ref, gsm_free_muxr);
3255 spin_unlock_irqrestore(&gsm_mux_lock, flags);
3256}
3257
3258static inline unsigned int mux_num_to_base(struct gsm_mux *gsm)
3259{
3260 return gsm->num * NUM_DLCI;
3261}
3262
3263static inline unsigned int mux_line_to_num(unsigned int line)
3264{
3265 return line / NUM_DLCI;
3266}
3267
3268/**
3269 * gsm_alloc_mux - allocate a mux
3270 *
3271 * Creates a new mux ready for activation.
3272 */
3273
3274static struct gsm_mux *gsm_alloc_mux(void)
3275{
3276 int i;
3277 struct gsm_mux *gsm = kzalloc_obj(struct gsm_mux);
3278 if (gsm == NULL)
3279 return NULL;
3280 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
3281 if (gsm->buf == NULL) {
3282 kfree(gsm);
3283 return NULL;
3284 }
3285 gsm->txframe = kmalloc(2 * (MAX_MTU + PROT_OVERHEAD - 1), GFP_KERNEL);
3286 if (gsm->txframe == NULL) {
3287 kfree(gsm->buf);
3288 kfree(gsm);
3289 return NULL;
3290 }
3291 spin_lock_init(&gsm->lock);
3292 mutex_init(&gsm->mutex);
3293 kref_init(&gsm->ref);
3294 INIT_LIST_HEAD(&gsm->tx_ctrl_list);
3295 INIT_LIST_HEAD(&gsm->tx_data_list);
3296 timer_setup(&gsm->kick_timer, gsm_kick_timer, 0);
3297 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
3298 timer_setup(&gsm->ka_timer, gsm_control_keep_alive, 0);
3299 INIT_WORK(&gsm->tx_work, gsmld_write_task);
3300 init_waitqueue_head(&gsm->event);
3301 spin_lock_init(&gsm->control_lock);
3302 spin_lock_init(&gsm->tx_lock);
3303
3304 gsm->t1 = T1;
3305 gsm->t2 = T2;
3306 gsm->t3 = T3;
3307 gsm->n2 = N2;
3308 gsm->k = K;
3309 gsm->ftype = UIH;
3310 gsm->adaption = 1;
3311 gsm->encoding = GSM_ADV_OPT;
3312 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
3313 gsm->mtu = 64;
3314 gsm->dead = true; /* Avoid early tty opens */
3315 gsm->wait_config = false; /* Disabled */
3316 gsm->keep_alive = 0; /* Disabled */
3317
3318 /* Store the instance to the mux array or abort if no space is
3319 * available.
3320 */
3321 spin_lock(&gsm_mux_lock);
3322 for (i = 0; i < MAX_MUX; i++) {
3323 if (!gsm_mux[i]) {
3324 gsm_mux[i] = gsm;
3325 gsm->num = i;
3326 break;
3327 }
3328 }
3329 spin_unlock(&gsm_mux_lock);
3330 if (i == MAX_MUX) {
3331 mutex_destroy(&gsm->mutex);
3332 kfree(gsm->txframe);
3333 kfree(gsm->buf);
3334 kfree(gsm);
3335 return NULL;
3336 }
3337
3338 return gsm;
3339}
3340
3341static void gsm_copy_config_values(struct gsm_mux *gsm,
3342 struct gsm_config *c)
3343{
3344 memset(c, 0, sizeof(*c));
3345 c->adaption = gsm->adaption;
3346 c->encapsulation = gsm->encoding;
3347 c->initiator = gsm->initiator;
3348 c->t1 = gsm->t1;
3349 c->t2 = gsm->t2;
3350 c->t3 = gsm->t3;
3351 c->n2 = gsm->n2;
3352 if (gsm->ftype == UIH)
3353 c->i = 1;
3354 else
3355 c->i = 2;
3356 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i);
3357 c->mru = gsm->mru;
3358 c->mtu = gsm->mtu;
3359 c->k = gsm->k;
3360}
3361
3362static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
3363{
3364 int need_close = 0;
3365 int need_restart = 0;
3366
3367 /* Stuff we don't support yet - UI or I frame transport */
3368 if (c->adaption != 1 && c->adaption != 2)
3369 return -EOPNOTSUPP;
3370 /* Check the MRU/MTU range looks sane */
3371 if (c->mru < MIN_MTU || c->mtu < MIN_MTU)
3372 return -EINVAL;
3373 if (c->mru > MAX_MRU || c->mtu > MAX_MTU)
3374 return -EINVAL;
3375 if (c->t3 > MAX_T3)
3376 return -EINVAL;
3377 if (c->n2 > 255)
3378 return -EINVAL;
3379 if (c->encapsulation > 1) /* Basic, advanced, no I */
3380 return -EINVAL;
3381 if (c->initiator > 1)
3382 return -EINVAL;
3383 if (c->k > MAX_WINDOW_SIZE)
3384 return -EINVAL;
3385 if (c->i == 0 || c->i > 2) /* UIH and UI only */
3386 return -EINVAL;
3387 /*
3388 * See what is needed for reconfiguration
3389 */
3390
3391 /* Timing fields */
3392 if (c->t1 != 0 && c->t1 != gsm->t1)
3393 need_restart = 1;
3394 if (c->t2 != 0 && c->t2 != gsm->t2)
3395 need_restart = 1;
3396 if (c->encapsulation != gsm->encoding)
3397 need_restart = 1;
3398 if (c->adaption != gsm->adaption)
3399 need_restart = 1;
3400 /* Requires care */
3401 if (c->initiator != gsm->initiator)
3402 need_close = 1;
3403 if (c->mru != gsm->mru)
3404 need_restart = 1;
3405 if (c->mtu != gsm->mtu)
3406 need_restart = 1;
3407
3408 /*
3409 * Close down what is needed, restart and initiate the new
3410 * configuration. On the first time there is no DLCI[0]
3411 * and closing or cleaning up is not necessary.
3412 */
3413 if (need_close || need_restart)
3414 gsm_cleanup_mux(gsm, true);
3415
3416 gsm->initiator = c->initiator;
3417 gsm->mru = c->mru;
3418 gsm->mtu = c->mtu;
3419 gsm->encoding = c->encapsulation ? GSM_ADV_OPT : GSM_BASIC_OPT;
3420 gsm->adaption = c->adaption;
3421 gsm->n2 = c->n2;
3422
3423 if (c->i == 1)
3424 gsm->ftype = UIH;
3425 else if (c->i == 2)
3426 gsm->ftype = UI;
3427
3428 if (c->t1)
3429 gsm->t1 = c->t1;
3430 if (c->t2)
3431 gsm->t2 = c->t2;
3432 if (c->t3)
3433 gsm->t3 = c->t3;
3434 if (c->k)
3435 gsm->k = c->k;
3436
3437 /*
3438 * FIXME: We need to separate activation/deactivation from adding
3439 * and removing from the mux array
3440 */
3441 if (gsm->dead) {
3442 int ret = gsm_activate_mux(gsm);
3443 if (ret)
3444 return ret;
3445 if (gsm->initiator)
3446 gsm_dlci_begin_open(gsm->dlci[0]);
3447 }
3448 return 0;
3449}
3450
3451static void gsm_copy_config_ext_values(struct gsm_mux *gsm,
3452 struct gsm_config_ext *ce)
3453{
3454 memset(ce, 0, sizeof(*ce));
3455 ce->wait_config = gsm->wait_config ? 1 : 0;
3456 ce->keep_alive = gsm->keep_alive;
3457}
3458
3459static int gsm_config_ext(struct gsm_mux *gsm, struct gsm_config_ext *ce)
3460{
3461 bool need_restart = false;
3462 unsigned int i;
3463
3464 /*
3465 * Check that userspace doesn't put stuff in here to prevent breakages
3466 * in the future.
3467 */
3468 for (i = 0; i < ARRAY_SIZE(ce->reserved); i++)
3469 if (ce->reserved[i])
3470 return -EINVAL;
3471 if (ce->flags & ~GSM_FL_RESTART)
3472 return -EINVAL;
3473
3474 /* Requires care */
3475 if (ce->flags & GSM_FL_RESTART)
3476 need_restart = true;
3477
3478 /*
3479 * Close down what is needed, restart and initiate the new
3480 * configuration. On the first time there is no DLCI[0]
3481 * and closing or cleaning up is not necessary.
3482 */
3483 if (need_restart)
3484 gsm_cleanup_mux(gsm, true);
3485
3486 /*
3487 * Setup the new configuration values
3488 */
3489 gsm->wait_config = ce->wait_config ? true : false;
3490 gsm->keep_alive = ce->keep_alive;
3491
3492 if (gsm->dead) {
3493 int ret = gsm_activate_mux(gsm);
3494 if (ret)
3495 return ret;
3496 if (gsm->initiator)
3497 gsm_dlci_begin_open(gsm->dlci[0]);
3498 }
3499
3500 return 0;
3501}
3502
3503/**
3504 * gsmld_output - write to link
3505 * @gsm: our mux
3506 * @data: bytes to output
3507 * @len: size
3508 *
3509 * Write a block of data from the GSM mux to the data channel. This
3510 * will eventually be serialized from above but at the moment isn't.
3511 */
3512
3513static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
3514{
3515 if (tty_write_room(gsm->tty) < len) {
3516 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
3517 return -ENOSPC;
3518 }
3519 if (debug & DBG_DATA)
3520 gsm_hex_dump_bytes(__func__, data, len);
3521 return gsm->tty->ops->write(gsm->tty, data, len);
3522}
3523
3524
3525/**
3526 * gsmld_write_trigger - schedule ldisc write task
3527 * @gsm: our mux
3528 */
3529static void gsmld_write_trigger(struct gsm_mux *gsm)
3530{
3531 if (!gsm || !gsm->dlci[0] || gsm->dlci[0]->dead)
3532 return;
3533 schedule_work(&gsm->tx_work);
3534}
3535
3536
3537/**
3538 * gsmld_write_task - ldisc write task
3539 * @work: our tx write work
3540 *
3541 * Writes out data to the ldisc if possible. We are doing this here to
3542 * avoid dead-locking. This returns if no space or data is left for output.
3543 */
3544static void gsmld_write_task(struct work_struct *work)
3545{
3546 struct gsm_mux *gsm = container_of(work, struct gsm_mux, tx_work);
3547 unsigned long flags;
3548 int i, ret;
3549
3550 /* All outstanding control channel and control messages and one data
3551 * frame is sent.
3552 */
3553 ret = -ENODEV;
3554 spin_lock_irqsave(&gsm->tx_lock, flags);
3555 if (gsm->tty)
3556 ret = gsm_data_kick(gsm);
3557 spin_unlock_irqrestore(&gsm->tx_lock, flags);
3558
3559 if (ret >= 0)
3560 for (i = 0; i < NUM_DLCI; i++)
3561 if (gsm->dlci[i])
3562 tty_port_tty_wakeup(&gsm->dlci[i]->port);
3563}
3564
3565/**
3566 * gsmld_attach_gsm - mode set up
3567 * @tty: our tty structure
3568 * @gsm: our mux
3569 *
3570 * Set up the MUX for basic mode and commence connecting to the
3571 * modem. Currently called from the line discipline set up but
3572 * will need moving to an ioctl path.
3573 */
3574
3575static void gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
3576{
3577 gsm->tty = tty_kref_get(tty);
3578 /* Turn off tty XON/XOFF handling to handle it explicitly. */
3579 gsm->old_c_iflag = tty->termios.c_iflag;
3580 tty->termios.c_iflag &= (IXON | IXOFF);
3581}
3582
3583/**
3584 * gsmld_detach_gsm - stop doing 0710 mux
3585 * @tty: tty attached to the mux
3586 * @gsm: mux
3587 *
3588 * Shutdown and then clean up the resources used by the line discipline
3589 */
3590
3591static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
3592{
3593 WARN_ON(tty != gsm->tty);
3594 /* Restore tty XON/XOFF handling. */
3595 gsm->tty->termios.c_iflag = gsm->old_c_iflag;
3596 tty_kref_put(gsm->tty);
3597 gsm->tty = NULL;
3598}
3599
3600static void gsmld_receive_buf(struct tty_struct *tty, const u8 *cp,
3601 const u8 *fp, size_t count)
3602{
3603 struct gsm_mux *gsm = tty->disc_data;
3604 u8 flags = TTY_NORMAL;
3605
3606 if (debug & DBG_DATA)
3607 gsm_hex_dump_bytes(__func__, cp, count);
3608
3609 for (; count; count--, cp++) {
3610 if (fp)
3611 flags = *fp++;
3612 switch (flags) {
3613 case TTY_NORMAL:
3614 if (gsm->receive)
3615 gsm->receive(gsm, *cp);
3616 break;
3617 case TTY_OVERRUN:
3618 case TTY_BREAK:
3619 case TTY_PARITY:
3620 case TTY_FRAME:
3621 gsm_error(gsm);
3622 break;
3623 default:
3624 WARN_ONCE(1, "%s: unknown flag %d\n",
3625 tty_name(tty), flags);
3626 break;
3627 }
3628 }
3629 /* FASYNC if needed ? */
3630 /* If clogged call tty_throttle(tty); */
3631}
3632
3633/**
3634 * gsmld_flush_buffer - clean input queue
3635 * @tty: terminal device
3636 *
3637 * Flush the input buffer. Called when the line discipline is
3638 * being closed, when the tty layer wants the buffer flushed (eg
3639 * at hangup).
3640 */
3641
3642static void gsmld_flush_buffer(struct tty_struct *tty)
3643{
3644}
3645
3646/**
3647 * gsmld_close - close the ldisc for this tty
3648 * @tty: device
3649 *
3650 * Called from the terminal layer when this line discipline is
3651 * being shut down, either because of a close or becsuse of a
3652 * discipline change. The function will not be called while other
3653 * ldisc methods are in progress.
3654 */
3655
3656static void gsmld_close(struct tty_struct *tty)
3657{
3658 struct gsm_mux *gsm = tty->disc_data;
3659
3660 /* The ldisc locks and closes the port before calling our close. This
3661 * means we have no way to do a proper disconnect. We will not bother
3662 * to do one.
3663 */
3664 gsm_cleanup_mux(gsm, false);
3665
3666 gsmld_detach_gsm(tty, gsm);
3667
3668 gsmld_flush_buffer(tty);
3669 /* Do other clean up here */
3670 mux_put(gsm);
3671}
3672
3673/**
3674 * gsmld_open - open an ldisc
3675 * @tty: terminal to open
3676 *
3677 * Called when this line discipline is being attached to the
3678 * terminal device. Can sleep. Called serialized so that no
3679 * other events will occur in parallel. No further open will occur
3680 * until a close.
3681 */
3682
3683static int gsmld_open(struct tty_struct *tty)
3684{
3685 struct gsm_mux *gsm;
3686
3687 if (!capable(CAP_NET_ADMIN))
3688 return -EPERM;
3689
3690 if (tty->ops->write == NULL)
3691 return -EINVAL;
3692
3693 /* Attach our ldisc data */
3694 gsm = gsm_alloc_mux();
3695 if (gsm == NULL)
3696 return -ENOMEM;
3697
3698 tty->disc_data = gsm;
3699 tty->receive_room = 65536;
3700
3701 /* Attach the initial passive connection */
3702 gsmld_attach_gsm(tty, gsm);
3703
3704 /* The mux will not be activated yet, we wait for correct
3705 * configuration first.
3706 */
3707 if (gsm->encoding == GSM_BASIC_OPT)
3708 gsm->receive = gsm0_receive;
3709 else
3710 gsm->receive = gsm1_receive;
3711
3712 return 0;
3713}
3714
3715/**
3716 * gsmld_write_wakeup - asynchronous I/O notifier
3717 * @tty: tty device
3718 *
3719 * Required for the ptys, serial driver etc. since processes
3720 * that attach themselves to the master and rely on ASYNC
3721 * IO must be woken up
3722 */
3723
3724static void gsmld_write_wakeup(struct tty_struct *tty)
3725{
3726 struct gsm_mux *gsm = tty->disc_data;
3727
3728 /* Queue poll */
3729 gsmld_write_trigger(gsm);
3730}
3731
3732/**
3733 * gsmld_read - read function for tty
3734 * @tty: tty device
3735 * @file: file object
3736 * @buf: userspace buffer pointer
3737 * @nr: size of I/O
3738 * @cookie: unused
3739 * @offset: unused
3740 *
3741 * Perform reads for the line discipline. We are guaranteed that the
3742 * line discipline will not be closed under us but we may get multiple
3743 * parallel readers and must handle this ourselves. We may also get
3744 * a hangup. Always called in user context, may sleep.
3745 *
3746 * This code must be sure never to sleep through a hangup.
3747 */
3748
3749static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, u8 *buf,
3750 size_t nr, void **cookie, unsigned long offset)
3751{
3752 return -EOPNOTSUPP;
3753}
3754
3755/**
3756 * gsmld_write - write function for tty
3757 * @tty: tty device
3758 * @file: file object
3759 * @buf: userspace buffer pointer
3760 * @nr: size of I/O
3761 *
3762 * Called when the owner of the device wants to send a frame
3763 * itself (or some other control data). The data is transferred
3764 * as-is and must be properly framed and checksummed as appropriate
3765 * by userspace. Frames are either sent whole or not at all as this
3766 * avoids pain user side.
3767 */
3768
3769static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
3770 const u8 *buf, size_t nr)
3771{
3772 struct gsm_mux *gsm = tty->disc_data;
3773 unsigned long flags;
3774 size_t space;
3775 int ret;
3776
3777 if (!gsm)
3778 return -ENODEV;
3779
3780 ret = -ENOBUFS;
3781 spin_lock_irqsave(&gsm->tx_lock, flags);
3782 space = tty_write_room(tty);
3783 if (space >= nr)
3784 ret = tty->ops->write(tty, buf, nr);
3785 else
3786 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
3787 spin_unlock_irqrestore(&gsm->tx_lock, flags);
3788
3789 return ret;
3790}
3791
3792/**
3793 * gsmld_poll - poll method for N_GSM0710
3794 * @tty: terminal device
3795 * @file: file accessing it
3796 * @wait: poll table
3797 *
3798 * Called when the line discipline is asked to poll() for data or
3799 * for special events. This code is not serialized with respect to
3800 * other events save open/close.
3801 *
3802 * This code must be sure never to sleep through a hangup.
3803 * Called without the kernel lock held - fine
3804 */
3805
3806static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
3807 poll_table *wait)
3808{
3809 __poll_t mask = 0;
3810 struct gsm_mux *gsm = tty->disc_data;
3811
3812 poll_wait(file, &tty->read_wait, wait);
3813 poll_wait(file, &tty->write_wait, wait);
3814
3815 if (gsm->dead)
3816 mask |= EPOLLHUP;
3817 if (tty_hung_up_p(file))
3818 mask |= EPOLLHUP;
3819 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
3820 mask |= EPOLLHUP;
3821 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
3822 mask |= EPOLLOUT | EPOLLWRNORM;
3823 return mask;
3824}
3825
3826static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd,
3827 unsigned long arg)
3828{
3829 struct gsm_config c;
3830 struct gsm_config_ext ce;
3831 struct gsm_dlci_config dc;
3832 struct gsm_mux *gsm = tty->disc_data;
3833 unsigned int base, addr;
3834 struct gsm_dlci *dlci;
3835
3836 switch (cmd) {
3837 case GSMIOC_GETCONF:
3838 gsm_copy_config_values(gsm, &c);
3839 if (copy_to_user((void __user *)arg, &c, sizeof(c)))
3840 return -EFAULT;
3841 return 0;
3842 case GSMIOC_SETCONF:
3843 if (copy_from_user(&c, (void __user *)arg, sizeof(c)))
3844 return -EFAULT;
3845 return gsm_config(gsm, &c);
3846 case GSMIOC_GETFIRST:
3847 base = mux_num_to_base(gsm);
3848 return put_user(base + 1, (__u32 __user *)arg);
3849 case GSMIOC_GETCONF_EXT:
3850 gsm_copy_config_ext_values(gsm, &ce);
3851 if (copy_to_user((void __user *)arg, &ce, sizeof(ce)))
3852 return -EFAULT;
3853 return 0;
3854 case GSMIOC_SETCONF_EXT:
3855 if (copy_from_user(&ce, (void __user *)arg, sizeof(ce)))
3856 return -EFAULT;
3857 return gsm_config_ext(gsm, &ce);
3858 case GSMIOC_GETCONF_DLCI:
3859 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc)))
3860 return -EFAULT;
3861 if (dc.channel == 0 || dc.channel >= NUM_DLCI)
3862 return -EINVAL;
3863 addr = array_index_nospec(dc.channel, NUM_DLCI);
3864 dlci = gsm->dlci[addr];
3865 if (!dlci) {
3866 dlci = gsm_dlci_alloc(gsm, addr);
3867 if (!dlci)
3868 return -ENOMEM;
3869 }
3870 gsm_dlci_copy_config_values(dlci, &dc);
3871 if (copy_to_user((void __user *)arg, &dc, sizeof(dc)))
3872 return -EFAULT;
3873 return 0;
3874 case GSMIOC_SETCONF_DLCI:
3875 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc)))
3876 return -EFAULT;
3877 if (dc.channel == 0 || dc.channel >= NUM_DLCI)
3878 return -EINVAL;
3879 addr = array_index_nospec(dc.channel, NUM_DLCI);
3880 dlci = gsm->dlci[addr];
3881 if (!dlci) {
3882 dlci = gsm_dlci_alloc(gsm, addr);
3883 if (!dlci)
3884 return -ENOMEM;
3885 }
3886 return gsm_dlci_config(dlci, &dc, 0);
3887 default:
3888 return n_tty_ioctl_helper(tty, cmd, arg);
3889 }
3890}
3891
3892/*
3893 * Network interface
3894 *
3895 */
3896
3897static int gsm_mux_net_open(struct net_device *net)
3898{
3899 pr_debug("%s called\n", __func__);
3900 netif_start_queue(net);
3901 return 0;
3902}
3903
3904static int gsm_mux_net_close(struct net_device *net)
3905{
3906 netif_stop_queue(net);
3907 return 0;
3908}
3909
3910static void dlci_net_free(struct gsm_dlci *dlci)
3911{
3912 if (!dlci->net) {
3913 WARN_ON(1);
3914 return;
3915 }
3916 dlci->adaption = dlci->prev_adaption;
3917 dlci->data = dlci->prev_data;
3918 free_netdev(dlci->net);
3919 dlci->net = NULL;
3920}
3921static void net_free(struct kref *ref)
3922{
3923 struct gsm_mux_net *mux_net;
3924 struct gsm_dlci *dlci;
3925
3926 mux_net = container_of(ref, struct gsm_mux_net, ref);
3927 dlci = mux_net->dlci;
3928
3929 if (dlci->net) {
3930 unregister_netdev(dlci->net);
3931 dlci_net_free(dlci);
3932 }
3933}
3934
3935static inline void muxnet_get(struct gsm_mux_net *mux_net)
3936{
3937 kref_get(&mux_net->ref);
3938}
3939
3940static inline void muxnet_put(struct gsm_mux_net *mux_net)
3941{
3942 kref_put(&mux_net->ref, net_free);
3943}
3944
3945static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
3946 struct net_device *net)
3947{
3948 struct gsm_mux_net *mux_net = netdev_priv(net);
3949 struct gsm_dlci *dlci = mux_net->dlci;
3950 muxnet_get(mux_net);
3951
3952 skb_queue_head(&dlci->skb_list, skb);
3953 net->stats.tx_packets++;
3954 net->stats.tx_bytes += skb->len;
3955 gsm_dlci_data_kick(dlci);
3956 /* And tell the kernel when the last transmit started. */
3957 netif_trans_update(net);
3958 muxnet_put(mux_net);
3959 return NETDEV_TX_OK;
3960}
3961
3962/* called when a packet did not ack after watchdogtimeout */
3963static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue)
3964{
3965 /* Tell syslog we are hosed. */
3966 dev_dbg(&net->dev, "Tx timed out.\n");
3967
3968 /* Update statistics */
3969 net->stats.tx_errors++;
3970}
3971
3972static void gsm_mux_rx_netchar(struct gsm_dlci *dlci, const u8 *in_buf, int size)
3973{
3974 struct net_device *net = dlci->net;
3975 struct sk_buff *skb;
3976 struct gsm_mux_net *mux_net = netdev_priv(net);
3977 muxnet_get(mux_net);
3978
3979 /* Allocate an sk_buff */
3980 skb = dev_alloc_skb(size + NET_IP_ALIGN);
3981 if (!skb) {
3982 /* We got no receive buffer. */
3983 net->stats.rx_dropped++;
3984 muxnet_put(mux_net);
3985 return;
3986 }
3987 skb_reserve(skb, NET_IP_ALIGN);
3988 skb_put_data(skb, in_buf, size);
3989
3990 skb->dev = net;
3991 skb->protocol = htons(ETH_P_IP);
3992
3993 /* Ship it off to the kernel */
3994 netif_rx(skb);
3995
3996 /* update out statistics */
3997 net->stats.rx_packets++;
3998 net->stats.rx_bytes += size;
3999 muxnet_put(mux_net);
4000 return;
4001}
4002
4003static void gsm_mux_net_init(struct net_device *net)
4004{
4005 static const struct net_device_ops gsm_netdev_ops = {
4006 .ndo_open = gsm_mux_net_open,
4007 .ndo_stop = gsm_mux_net_close,
4008 .ndo_start_xmit = gsm_mux_net_start_xmit,
4009 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
4010 };
4011
4012 net->netdev_ops = &gsm_netdev_ops;
4013
4014 /* fill in the other fields */
4015 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
4016 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
4017 net->type = ARPHRD_NONE;
4018 net->tx_queue_len = 10;
4019}
4020
4021
4022/* caller holds the dlci mutex */
4023static void gsm_destroy_network(struct gsm_dlci *dlci)
4024{
4025 struct gsm_mux_net *mux_net;
4026
4027 pr_debug("destroy network interface\n");
4028 if (!dlci->net)
4029 return;
4030 mux_net = netdev_priv(dlci->net);
4031 muxnet_put(mux_net);
4032}
4033
4034
4035/* caller holds the dlci mutex */
4036static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
4037{
4038 char *netname;
4039 int retval = 0;
4040 struct net_device *net;
4041 struct gsm_mux_net *mux_net;
4042
4043 if (!capable(CAP_NET_ADMIN))
4044 return -EPERM;
4045
4046 /* Already in a non tty mode */
4047 if (dlci->adaption > 2)
4048 return -EBUSY;
4049
4050 if (nc->protocol != htons(ETH_P_IP))
4051 return -EPROTONOSUPPORT;
4052
4053 if (nc->adaption != 3 && nc->adaption != 4)
4054 return -EPROTONOSUPPORT;
4055
4056 pr_debug("create network interface\n");
4057
4058 netname = "gsm%d";
4059 if (nc->if_name[0] != '\0')
4060 netname = nc->if_name;
4061 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
4062 NET_NAME_UNKNOWN, gsm_mux_net_init);
4063 if (!net) {
4064 pr_err("alloc_netdev failed\n");
4065 return -ENOMEM;
4066 }
4067 net->mtu = dlci->mtu;
4068 net->min_mtu = MIN_MTU;
4069 net->max_mtu = dlci->mtu;
4070 mux_net = netdev_priv(net);
4071 mux_net->dlci = dlci;
4072 kref_init(&mux_net->ref);
4073 strscpy(nc->if_name, net->name); /* return net name */
4074
4075 /* reconfigure dlci for network */
4076 dlci->prev_adaption = dlci->adaption;
4077 dlci->prev_data = dlci->data;
4078 dlci->adaption = nc->adaption;
4079 dlci->data = gsm_mux_rx_netchar;
4080 dlci->net = net;
4081
4082 pr_debug("register netdev\n");
4083 retval = register_netdev(net);
4084 if (retval) {
4085 pr_err("network register fail %d\n", retval);
4086 dlci_net_free(dlci);
4087 return retval;
4088 }
4089 return net->ifindex; /* return network index */
4090}
4091
4092/* Line discipline for real tty */
4093static struct tty_ldisc_ops tty_ldisc_packet = {
4094 .owner = THIS_MODULE,
4095 .num = N_GSM0710,
4096 .name = "n_gsm",
4097 .open = gsmld_open,
4098 .close = gsmld_close,
4099 .flush_buffer = gsmld_flush_buffer,
4100 .read = gsmld_read,
4101 .write = gsmld_write,
4102 .ioctl = gsmld_ioctl,
4103 .poll = gsmld_poll,
4104 .receive_buf = gsmld_receive_buf,
4105 .write_wakeup = gsmld_write_wakeup
4106};
4107
4108/*
4109 * Virtual tty side
4110 */
4111
4112/**
4113 * gsm_modem_upd_via_data - send modem bits via convergence layer
4114 * @dlci: channel
4115 * @brk: break signal
4116 *
4117 * Send an empty frame to signal mobile state changes and to transmit the
4118 * break signal for adaption 2.
4119 */
4120
4121static void gsm_modem_upd_via_data(struct gsm_dlci *dlci, u8 brk)
4122{
4123 struct gsm_mux *gsm = dlci->gsm;
4124 unsigned long flags;
4125
4126 if (dlci->state != DLCI_OPEN || dlci->adaption != 2)
4127 return;
4128
4129 spin_lock_irqsave(&gsm->tx_lock, flags);
4130 gsm_dlci_modem_output(gsm, dlci, brk);
4131 spin_unlock_irqrestore(&gsm->tx_lock, flags);
4132}
4133
4134/**
4135 * gsm_modem_upd_via_msc - send modem bits via control frame
4136 * @dlci: channel
4137 * @brk: break signal
4138 * @wait: wait for the MSC command
4139 */
4140
4141static int gsm_modem_upd_via_msc(struct gsm_dlci *dlci, u8 brk, bool wait)
4142{
4143 u8 modembits[3];
4144 struct gsm_control *ctrl;
4145 int len = 2;
4146
4147 if (dlci->gsm->encoding != GSM_BASIC_OPT)
4148 return 0;
4149
4150 modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */
4151 if (!brk) {
4152 modembits[1] = (gsm_encode_modem(dlci) << 1) | EA;
4153 } else {
4154 modembits[1] = gsm_encode_modem(dlci) << 1;
4155 modembits[2] = (brk << 4) | 2 | EA; /* Length, Break, EA */
4156 len++;
4157 }
4158 if (!wait)
4159 return gsm_control_command(dlci->gsm, CMD_MSC, modembits, len);
4160 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len);
4161 if (ctrl == NULL)
4162 return -ENOMEM;
4163 return gsm_control_wait(dlci->gsm, ctrl);
4164}
4165
4166/**
4167 * gsm_modem_update - send modem status line state
4168 * @dlci: channel
4169 * @brk: break signal
4170 * @wait: wait for the MSC command
4171 */
4172
4173static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk, bool wait)
4174{
4175 if (dlci->gsm->dead)
4176 return -EL2HLT;
4177 if (dlci->adaption == 2) {
4178 /* Send convergence layer type 2 empty data frame. */
4179 gsm_modem_upd_via_data(dlci, brk);
4180 return 0;
4181 } else if (dlci->gsm->encoding == GSM_BASIC_OPT) {
4182 /* Send as MSC control message. */
4183 return gsm_modem_upd_via_msc(dlci, brk, wait);
4184 }
4185
4186 /* Modem status lines are not supported. */
4187 return -EPROTONOSUPPORT;
4188}
4189
4190/**
4191 * gsm_wait_modem_change - wait for modem status line change
4192 * @dlci: channel
4193 * @mask: modem status line bits
4194 *
4195 * The function returns if:
4196 * - any given modem status line bit changed
4197 * - the wait event function got interrupted (e.g. by a signal)
4198 * - the underlying DLCI was closed
4199 * - the underlying ldisc device was removed
4200 */
4201static int gsm_wait_modem_change(struct gsm_dlci *dlci, u32 mask)
4202{
4203 struct gsm_mux *gsm = dlci->gsm;
4204 u32 old = dlci->modem_rx;
4205 int ret;
4206
4207 ret = wait_event_interruptible(gsm->event, gsm->dead ||
4208 dlci->state != DLCI_OPEN ||
4209 (old ^ dlci->modem_rx) & mask);
4210 if (gsm->dead)
4211 return -ENODEV;
4212 if (dlci->state != DLCI_OPEN)
4213 return -EL2NSYNC;
4214 return ret;
4215}
4216
4217static bool gsm_carrier_raised(struct tty_port *port)
4218{
4219 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
4220 struct gsm_mux *gsm = dlci->gsm;
4221
4222 /* Not yet open so no carrier info */
4223 if (dlci->state != DLCI_OPEN)
4224 return false;
4225 if (debug & DBG_CD_ON)
4226 return true;
4227
4228 /*
4229 * Basic mode with control channel in ADM mode may not respond
4230 * to CMD_MSC at all and modem_rx is empty.
4231 */
4232 if (gsm->encoding == GSM_BASIC_OPT &&
4233 gsm->dlci[0]->mode == DLCI_MODE_ADM && !dlci->modem_rx)
4234 return true;
4235
4236 return dlci->modem_rx & TIOCM_CD;
4237}
4238
4239static void gsm_dtr_rts(struct tty_port *port, bool active)
4240{
4241 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
4242 unsigned int modem_tx = dlci->modem_tx;
4243 if (active)
4244 modem_tx |= TIOCM_DTR | TIOCM_RTS;
4245 else
4246 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
4247 if (modem_tx != dlci->modem_tx) {
4248 dlci->modem_tx = modem_tx;
4249 gsm_modem_update(dlci, 0, true);
4250 }
4251}
4252
4253static const struct tty_port_operations gsm_port_ops = {
4254 .carrier_raised = gsm_carrier_raised,
4255 .dtr_rts = gsm_dtr_rts,
4256 .destruct = gsm_dlci_free,
4257};
4258
4259static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
4260{
4261 struct gsm_mux *gsm;
4262 struct gsm_dlci *dlci, *dlci0;
4263 unsigned int line = tty->index;
4264 unsigned int mux = mux_line_to_num(line);
4265 bool alloc = false;
4266 int ret;
4267
4268 line = line & 0x3F;
4269
4270 if (mux >= MAX_MUX)
4271 return -ENXIO;
4272 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
4273 if (gsm_mux[mux] == NULL)
4274 return -EUNATCH;
4275 if (line == 0 || line > 61) /* 62/63 reserved */
4276 return -ECHRNG;
4277 gsm = gsm_mux[mux];
4278 if (gsm->dead)
4279 return -EL2HLT;
4280 /* If DLCI 0 is not yet fully open return an error.
4281 This is ok from a locking
4282 perspective as we don't have to worry about this
4283 if DLCI0 is lost */
4284 mutex_lock(&gsm->mutex);
4285
4286 dlci0 = gsm->dlci[0];
4287 if (dlci0 && dlci0->state != DLCI_OPEN) {
4288 mutex_unlock(&gsm->mutex);
4289
4290 if (dlci0->state == DLCI_OPENING)
4291 wait_event(gsm->event, dlci0->state != DLCI_OPENING);
4292
4293 if (dlci0->state != DLCI_OPEN)
4294 return -EL2NSYNC;
4295
4296 mutex_lock(&gsm->mutex);
4297 }
4298
4299 dlci = gsm->dlci[line];
4300 if (dlci == NULL) {
4301 alloc = true;
4302 dlci = gsm_dlci_alloc(gsm, line);
4303 }
4304 if (dlci == NULL) {
4305 mutex_unlock(&gsm->mutex);
4306 return -ENOMEM;
4307 }
4308 ret = tty_port_install(&dlci->port, driver, tty);
4309 if (ret) {
4310 if (alloc)
4311 dlci_put(dlci);
4312 mutex_unlock(&gsm->mutex);
4313 return ret;
4314 }
4315
4316 dlci_get(dlci);
4317 dlci_get(gsm->dlci[0]);
4318 mux_get(gsm);
4319 tty->driver_data = dlci;
4320 mutex_unlock(&gsm->mutex);
4321
4322 return 0;
4323}
4324
4325static int gsmtty_open(struct tty_struct *tty, struct file *filp)
4326{
4327 struct gsm_dlci *dlci = tty->driver_data;
4328 struct tty_port *port = &dlci->port;
4329
4330 port->count++;
4331 tty_port_tty_set(port, tty);
4332
4333 dlci->modem_rx = 0;
4334 /* We could in theory open and close before we wait - eg if we get
4335 a DM straight back. This is ok as that will have caused a hangup */
4336 tty_port_set_initialized(port, true);
4337 /* Start sending off SABM messages */
4338 if (!dlci->gsm->wait_config) {
4339 /* Start sending off SABM messages */
4340 if (dlci->gsm->initiator)
4341 gsm_dlci_begin_open(dlci);
4342 else
4343 gsm_dlci_set_opening(dlci);
4344 } else {
4345 gsm_dlci_set_wait_config(dlci);
4346 }
4347 /* And wait for virtual carrier */
4348 return tty_port_block_til_ready(port, tty, filp);
4349}
4350
4351static void gsmtty_close(struct tty_struct *tty, struct file *filp)
4352{
4353 struct gsm_dlci *dlci = tty->driver_data;
4354
4355 if (dlci == NULL)
4356 return;
4357 if (dlci->state == DLCI_CLOSED)
4358 return;
4359 mutex_lock(&dlci->mutex);
4360 gsm_destroy_network(dlci);
4361 mutex_unlock(&dlci->mutex);
4362 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
4363 return;
4364 gsm_dlci_begin_close(dlci);
4365 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
4366 tty_port_lower_dtr_rts(&dlci->port);
4367 tty_port_close_end(&dlci->port, tty);
4368 tty_port_tty_set(&dlci->port, NULL);
4369 return;
4370}
4371
4372static void gsmtty_hangup(struct tty_struct *tty)
4373{
4374 struct gsm_dlci *dlci = tty->driver_data;
4375 if (dlci->state == DLCI_CLOSED)
4376 return;
4377 tty_port_hangup(&dlci->port);
4378 gsm_dlci_begin_close(dlci);
4379}
4380
4381static ssize_t gsmtty_write(struct tty_struct *tty, const u8 *buf, size_t len)
4382{
4383 int sent;
4384 struct gsm_dlci *dlci = tty->driver_data;
4385 if (dlci->state == DLCI_CLOSED)
4386 return -EINVAL;
4387 /* Stuff the bytes into the fifo queue */
4388 sent = kfifo_in_locked(&dlci->fifo, buf, len, &dlci->lock);
4389 /* Need to kick the channel */
4390 gsm_dlci_data_kick(dlci);
4391 return sent;
4392}
4393
4394static unsigned int gsmtty_write_room(struct tty_struct *tty)
4395{
4396 struct gsm_dlci *dlci = tty->driver_data;
4397 if (dlci->state == DLCI_CLOSED)
4398 return 0;
4399 return kfifo_avail(&dlci->fifo);
4400}
4401
4402static unsigned int gsmtty_chars_in_buffer(struct tty_struct *tty)
4403{
4404 struct gsm_dlci *dlci = tty->driver_data;
4405 if (dlci->state == DLCI_CLOSED)
4406 return 0;
4407 return kfifo_len(&dlci->fifo);
4408}
4409
4410static void gsmtty_flush_buffer(struct tty_struct *tty)
4411{
4412 struct gsm_dlci *dlci = tty->driver_data;
4413 unsigned long flags;
4414
4415 if (dlci->state == DLCI_CLOSED)
4416 return;
4417 /* Caution needed: If we implement reliable transport classes
4418 then the data being transmitted can't simply be junked once
4419 it has first hit the stack. Until then we can just blow it
4420 away */
4421 spin_lock_irqsave(&dlci->lock, flags);
4422 kfifo_reset(&dlci->fifo);
4423 spin_unlock_irqrestore(&dlci->lock, flags);
4424 /* Need to unhook this DLCI from the transmit queue logic */
4425}
4426
4427static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
4428{
4429 /* The FIFO handles the queue so the kernel will do the right
4430 thing waiting on chars_in_buffer before calling us. No work
4431 to do here */
4432}
4433
4434static int gsmtty_tiocmget(struct tty_struct *tty)
4435{
4436 struct gsm_dlci *dlci = tty->driver_data;
4437 if (dlci->state == DLCI_CLOSED)
4438 return -EINVAL;
4439 return dlci->modem_rx;
4440}
4441
4442static int gsmtty_tiocmset(struct tty_struct *tty,
4443 unsigned int set, unsigned int clear)
4444{
4445 struct gsm_dlci *dlci = tty->driver_data;
4446 unsigned int modem_tx = dlci->modem_tx;
4447
4448 if (dlci->state == DLCI_CLOSED)
4449 return -EINVAL;
4450 modem_tx &= ~clear;
4451 modem_tx |= set;
4452
4453 if (modem_tx != dlci->modem_tx) {
4454 dlci->modem_tx = modem_tx;
4455 return gsm_modem_update(dlci, 0, true);
4456 }
4457 return 0;
4458}
4459
4460
4461static int gsmtty_ioctl(struct tty_struct *tty,
4462 unsigned int cmd, unsigned long arg)
4463{
4464 struct gsm_dlci *dlci = tty->driver_data;
4465 struct gsm_netconfig nc;
4466 struct gsm_dlci_config dc;
4467 int index;
4468
4469 if (dlci->state == DLCI_CLOSED)
4470 return -EINVAL;
4471 switch (cmd) {
4472 case GSMIOC_ENABLE_NET:
4473 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
4474 return -EFAULT;
4475 nc.if_name[IFNAMSIZ-1] = '\0';
4476 /* return net interface index or error code */
4477 mutex_lock(&dlci->mutex);
4478 index = gsm_create_network(dlci, &nc);
4479 mutex_unlock(&dlci->mutex);
4480 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
4481 return -EFAULT;
4482 return index;
4483 case GSMIOC_DISABLE_NET:
4484 if (!capable(CAP_NET_ADMIN))
4485 return -EPERM;
4486 mutex_lock(&dlci->mutex);
4487 gsm_destroy_network(dlci);
4488 mutex_unlock(&dlci->mutex);
4489 return 0;
4490 case GSMIOC_GETCONF_DLCI:
4491 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc)))
4492 return -EFAULT;
4493 if (dc.channel != dlci->addr)
4494 return -EPERM;
4495 gsm_dlci_copy_config_values(dlci, &dc);
4496 if (copy_to_user((void __user *)arg, &dc, sizeof(dc)))
4497 return -EFAULT;
4498 return 0;
4499 case GSMIOC_SETCONF_DLCI:
4500 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc)))
4501 return -EFAULT;
4502 if (dc.channel >= NUM_DLCI)
4503 return -EINVAL;
4504 if (dc.channel != 0 && dc.channel != dlci->addr)
4505 return -EPERM;
4506 return gsm_dlci_config(dlci, &dc, 1);
4507 case TIOCMIWAIT:
4508 return gsm_wait_modem_change(dlci, (u32)arg);
4509 default:
4510 return -ENOIOCTLCMD;
4511 }
4512}
4513
4514static void gsmtty_set_termios(struct tty_struct *tty,
4515 const struct ktermios *old)
4516{
4517 struct gsm_dlci *dlci = tty->driver_data;
4518 if (dlci->state == DLCI_CLOSED)
4519 return;
4520 /* For the moment its fixed. In actual fact the speed information
4521 for the virtual channel can be propogated in both directions by
4522 the RPN control message. This however rapidly gets nasty as we
4523 then have to remap modem signals each way according to whether
4524 our virtual cable is null modem etc .. */
4525 tty_termios_copy_hw(&tty->termios, old);
4526}
4527
4528static void gsmtty_throttle(struct tty_struct *tty)
4529{
4530 struct gsm_dlci *dlci = tty->driver_data;
4531 if (dlci->state == DLCI_CLOSED)
4532 return;
4533 if (C_CRTSCTS(tty))
4534 dlci->modem_tx &= ~TIOCM_RTS;
4535 dlci->throttled = true;
4536 /* Send an MSC with RTS cleared */
4537 gsm_modem_update(dlci, 0, true);
4538}
4539
4540static void gsmtty_unthrottle(struct tty_struct *tty)
4541{
4542 struct gsm_dlci *dlci = tty->driver_data;
4543 if (dlci->state == DLCI_CLOSED)
4544 return;
4545 if (C_CRTSCTS(tty))
4546 dlci->modem_tx |= TIOCM_RTS;
4547 dlci->throttled = false;
4548 /* Send an MSC with RTS set */
4549 gsm_modem_update(dlci, 0, true);
4550}
4551
4552static int gsmtty_break_ctl(struct tty_struct *tty, int state)
4553{
4554 struct gsm_dlci *dlci = tty->driver_data;
4555 int encode = 0; /* Off */
4556 if (dlci->state == DLCI_CLOSED)
4557 return -EINVAL;
4558
4559 if (state == -1) /* "On indefinitely" - we can't encode this
4560 properly */
4561 encode = 0x0F;
4562 else if (state > 0) {
4563 encode = state / 200; /* mS to encoding */
4564 if (encode > 0x0F)
4565 encode = 0x0F; /* Best effort */
4566 }
4567 return gsm_modem_update(dlci, encode, true);
4568}
4569
4570static void gsmtty_cleanup(struct tty_struct *tty)
4571{
4572 struct gsm_dlci *dlci = tty->driver_data;
4573 struct gsm_mux *gsm = dlci->gsm;
4574
4575 dlci_put(dlci);
4576 dlci_put(gsm->dlci[0]);
4577 mux_put(gsm);
4578}
4579
4580/* Virtual ttys for the demux */
4581static const struct tty_operations gsmtty_ops = {
4582 .install = gsmtty_install,
4583 .open = gsmtty_open,
4584 .close = gsmtty_close,
4585 .write = gsmtty_write,
4586 .write_room = gsmtty_write_room,
4587 .chars_in_buffer = gsmtty_chars_in_buffer,
4588 .flush_buffer = gsmtty_flush_buffer,
4589 .ioctl = gsmtty_ioctl,
4590 .throttle = gsmtty_throttle,
4591 .unthrottle = gsmtty_unthrottle,
4592 .set_termios = gsmtty_set_termios,
4593 .hangup = gsmtty_hangup,
4594 .wait_until_sent = gsmtty_wait_until_sent,
4595 .tiocmget = gsmtty_tiocmget,
4596 .tiocmset = gsmtty_tiocmset,
4597 .break_ctl = gsmtty_break_ctl,
4598 .cleanup = gsmtty_cleanup,
4599};
4600
4601
4602
4603static int __init gsm_init(void)
4604{
4605 /* Fill in our line protocol discipline, and register it */
4606 int status = tty_register_ldisc(&tty_ldisc_packet);
4607 if (status != 0) {
4608 pr_err("n_gsm: can't register line discipline (err = %d)\n",
4609 status);
4610 return status;
4611 }
4612
4613 gsm_tty_driver = tty_alloc_driver(GSM_TTY_MINORS, TTY_DRIVER_REAL_RAW |
4614 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_HARDWARE_BREAK);
4615 if (IS_ERR(gsm_tty_driver)) {
4616 pr_err("gsm_init: tty allocation failed.\n");
4617 status = PTR_ERR(gsm_tty_driver);
4618 goto err_unreg_ldisc;
4619 }
4620 gsm_tty_driver->driver_name = "gsmtty";
4621 gsm_tty_driver->name = "gsmtty";
4622 gsm_tty_driver->major = 0; /* Dynamic */
4623 gsm_tty_driver->minor_start = 0;
4624 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
4625 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
4626 gsm_tty_driver->init_termios = tty_std_termios;
4627 /* Fixme */
4628 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
4629 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
4630
4631 if (tty_register_driver(gsm_tty_driver)) {
4632 pr_err("gsm_init: tty registration failed.\n");
4633 status = -EBUSY;
4634 goto err_put_driver;
4635 }
4636 pr_debug("gsm_init: loaded as %d,%d.\n",
4637 gsm_tty_driver->major, gsm_tty_driver->minor_start);
4638 return 0;
4639err_put_driver:
4640 tty_driver_kref_put(gsm_tty_driver);
4641err_unreg_ldisc:
4642 tty_unregister_ldisc(&tty_ldisc_packet);
4643 return status;
4644}
4645
4646static void __exit gsm_exit(void)
4647{
4648 tty_unregister_ldisc(&tty_ldisc_packet);
4649 tty_unregister_driver(gsm_tty_driver);
4650 tty_driver_kref_put(gsm_tty_driver);
4651}
4652
4653module_init(gsm_init);
4654module_exit(gsm_exit);
4655
4656
4657MODULE_DESCRIPTION("GSM 0710 tty multiplexor");
4658MODULE_LICENSE("GPL");
4659MODULE_ALIAS_LDISC(N_GSM0710);