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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * n_gsm.c GSM 0710 tty multiplexor
4 * Copyright (c) 2009/10 Intel Corporation
5 *
6 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
7 *
8 * Outgoing path:
9 * tty -> DLCI fifo -> scheduler -> GSM MUX data queue ---o-> ldisc
10 * control message -> GSM MUX control queue --ยด
11 *
12 * Incoming path:
13 * ldisc -> gsm_queue() -o--> tty
14 * `-> gsm_control_response()
15 *
16 * TO DO:
17 * Mostly done: ioctls for setting modes/timing
18 * Partly done: hooks so you can pull off frames to non tty devs
19 * Restart DLCI 0 when it closes ?
20 * Improve the tx engine
21 * Resolve tx side locking by adding a queue_head and routing
22 * all control traffic via it
23 * General tidy/document
24 * Review the locking/move to refcounts more (mux now moved to an
25 * alloc/free model ready)
26 * Use newest tty open/close port helpers and install hooks
27 * What to do about power functions ?
28 * Termios setting and negotiation
29 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
30 *
31 */
32
33#include <linux/types.h>
34#include <linux/major.h>
35#include <linux/errno.h>
36#include <linux/signal.h>
37#include <linux/fcntl.h>
38#include <linux/sched/signal.h>
39#include <linux/interrupt.h>
40#include <linux/tty.h>
41#include <linux/bitfield.h>
42#include <linux/ctype.h>
43#include <linux/mm.h>
44#include <linux/math.h>
45#include <linux/string.h>
46#include <linux/slab.h>
47#include <linux/poll.h>
48#include <linux/bitops.h>
49#include <linux/file.h>
50#include <linux/uaccess.h>
51#include <linux/module.h>
52#include <linux/timer.h>
53#include <linux/tty_flip.h>
54#include <linux/tty_driver.h>
55#include <linux/serial.h>
56#include <linux/kfifo.h>
57#include <linux/skbuff.h>
58#include <net/arp.h>
59#include <linux/ip.h>
60#include <linux/netdevice.h>
61#include <linux/etherdevice.h>
62#include <linux/gsmmux.h>
63#include "tty.h"
64
65static int debug;
66module_param(debug, int, 0600);
67
68/* Module debug bits */
69#define DBG_DUMP BIT(0) /* Data transmission dump. */
70#define DBG_CD_ON BIT(1) /* Always assume CD line on. */
71#define DBG_DATA BIT(2) /* Data transmission details. */
72#define DBG_ERRORS BIT(3) /* Details for fail conditions. */
73#define DBG_TTY BIT(4) /* Transmission statistics for DLCI TTYs. */
74#define DBG_PAYLOAD BIT(5) /* Limits DBG_DUMP to payload frames. */
75
76/* Defaults: these are from the specification */
77
78#define T1 10 /* 100mS */
79#define T2 34 /* 333mS */
80#define T3 10 /* 10s */
81#define N2 3 /* Retry 3 times */
82#define K 2 /* outstanding I frames */
83
84#define MAX_T3 255 /* In seconds. */
85#define MAX_WINDOW_SIZE 7 /* Limit of K in error recovery mode. */
86
87/* Use long timers for testing at low speed with debug on */
88#ifdef DEBUG_TIMING
89#define T1 100
90#define T2 200
91#endif
92
93/*
94 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
95 * limits so this is plenty
96 */
97#define MAX_MRU 1500
98#define MAX_MTU 1500
99#define MIN_MTU (PROT_OVERHEAD + 1)
100/* SOF, ADDR, CTRL, LEN1, LEN2, ..., FCS, EOF */
101#define PROT_OVERHEAD 7
102#define GSM_NET_TX_TIMEOUT (HZ*10)
103
104/*
105 * struct gsm_mux_net - network interface
106 *
107 * Created when net interface is initialized.
108 */
109struct gsm_mux_net {
110 struct kref ref;
111 struct gsm_dlci *dlci;
112};
113
114/*
115 * Each block of data we have queued to go out is in the form of
116 * a gsm_msg which holds everything we need in a link layer independent
117 * format
118 */
119
120struct gsm_msg {
121 struct list_head list;
122 u8 addr; /* DLCI address + flags */
123 u8 ctrl; /* Control byte + flags */
124 unsigned int len; /* Length of data block (can be zero) */
125 unsigned char *data; /* Points into buffer but not at the start */
126 unsigned char buffer[];
127};
128
129enum gsm_dlci_state {
130 DLCI_CLOSED,
131 DLCI_CONFIGURE, /* Sending PN (for adaption > 1) */
132 DLCI_OPENING, /* Sending SABM not seen UA */
133 DLCI_OPEN, /* SABM/UA complete */
134 DLCI_CLOSING, /* Sending DISC not seen UA/DM */
135};
136
137enum gsm_dlci_mode {
138 DLCI_MODE_ABM, /* Normal Asynchronous Balanced Mode */
139 DLCI_MODE_ADM, /* Asynchronous Disconnected Mode */
140};
141
142/*
143 * Each active data link has a gsm_dlci structure associated which ties
144 * the link layer to an optional tty (if the tty side is open). To avoid
145 * complexity right now these are only ever freed up when the mux is
146 * shut down.
147 *
148 * At the moment we don't free DLCI objects until the mux is torn down
149 * this avoid object life time issues but might be worth review later.
150 */
151
152struct gsm_dlci {
153 struct gsm_mux *gsm;
154 int addr;
155 enum gsm_dlci_state state;
156 struct mutex mutex;
157
158 /* Link layer */
159 enum gsm_dlci_mode mode;
160 spinlock_t lock; /* Protects the internal state */
161 struct timer_list t1; /* Retransmit timer for SABM and UA */
162 int retries;
163 /* Uplink tty if active */
164 struct tty_port port; /* The tty bound to this DLCI if there is one */
165#define TX_SIZE 4096 /* Must be power of 2. */
166 struct kfifo fifo; /* Queue fifo for the DLCI */
167 int adaption; /* Adaption layer in use */
168 int prev_adaption;
169 u32 modem_rx; /* Our incoming virtual modem lines */
170 u32 modem_tx; /* Our outgoing modem lines */
171 unsigned int mtu;
172 bool dead; /* Refuse re-open */
173 /* Configuration */
174 u8 prio; /* Priority */
175 u8 ftype; /* Frame type */
176 u8 k; /* Window size */
177 /* Flow control */
178 bool throttled; /* Private copy of throttle state */
179 bool constipated; /* Throttle status for outgoing */
180 /* Packetised I/O */
181 struct sk_buff *skb; /* Frame being sent */
182 struct sk_buff_head skb_list; /* Queued frames */
183 /* Data handling callback */
184 void (*data)(struct gsm_dlci *dlci, const u8 *data, int len);
185 void (*prev_data)(struct gsm_dlci *dlci, const u8 *data, int len);
186 struct net_device *net; /* network interface, if created */
187};
188
189/*
190 * Parameter bits used for parameter negotiation according to 3GPP 27.010
191 * chapter 5.4.6.3.1.
192 */
193
194struct gsm_dlci_param_bits {
195 u8 d_bits;
196 u8 i_cl_bits;
197 u8 p_bits;
198 u8 t_bits;
199 __le16 n_bits;
200 u8 na_bits;
201 u8 k_bits;
202};
203
204static_assert(sizeof(struct gsm_dlci_param_bits) == 8);
205
206#define PN_D_FIELD_DLCI GENMASK(5, 0)
207#define PN_I_CL_FIELD_FTYPE GENMASK(3, 0)
208#define PN_I_CL_FIELD_ADAPTION GENMASK(7, 4)
209#define PN_P_FIELD_PRIO GENMASK(5, 0)
210#define PN_T_FIELD_T1 GENMASK(7, 0)
211#define PN_N_FIELD_N1 GENMASK(15, 0)
212#define PN_NA_FIELD_N2 GENMASK(7, 0)
213#define PN_K_FIELD_K GENMASK(2, 0)
214
215/* Total number of supported devices */
216#define GSM_TTY_MINORS 256
217
218/* DLCI 0, 62/63 are special or reserved see gsmtty_open */
219
220#define NUM_DLCI 64
221
222/*
223 * DLCI 0 is used to pass control blocks out of band of the data
224 * flow (and with a higher link priority). One command can be outstanding
225 * at a time and we use this structure to manage them. They are created
226 * and destroyed by the user context, and updated by the receive paths
227 * and timers
228 */
229
230struct gsm_control {
231 u8 cmd; /* Command we are issuing */
232 u8 *data; /* Data for the command in case we retransmit */
233 int len; /* Length of block for retransmission */
234 int done; /* Done flag */
235 int error; /* Error if any */
236};
237
238enum gsm_encoding {
239 GSM_BASIC_OPT,
240 GSM_ADV_OPT,
241};
242
243enum gsm_mux_state {
244 GSM_SEARCH,
245 GSM_START,
246 GSM_ADDRESS,
247 GSM_CONTROL,
248 GSM_LEN,
249 GSM_DATA,
250 GSM_FCS,
251 GSM_OVERRUN,
252 GSM_LEN0,
253 GSM_LEN1,
254 GSM_SSOF,
255};
256
257/*
258 * Each GSM mux we have is represented by this structure. If we are
259 * operating as an ldisc then we use this structure as our ldisc
260 * state. We need to sort out lifetimes and locking with respect
261 * to the gsm mux array. For now we don't free DLCI objects that
262 * have been instantiated until the mux itself is terminated.
263 *
264 * To consider further: tty open versus mux shutdown.
265 */
266
267struct gsm_mux {
268 struct tty_struct *tty; /* The tty our ldisc is bound to */
269 spinlock_t lock;
270 struct mutex mutex;
271 unsigned int num;
272 struct kref ref;
273
274 /* Events on the GSM channel */
275 wait_queue_head_t event;
276
277 /* ldisc send work */
278 struct work_struct tx_work;
279
280 /* Bits for GSM mode decoding */
281
282 /* Framing Layer */
283 unsigned char *buf;
284 enum gsm_mux_state state;
285 unsigned int len;
286 unsigned int address;
287 unsigned int count;
288 bool escape;
289 enum gsm_encoding encoding;
290 u8 control;
291 u8 fcs;
292 u8 *txframe; /* TX framing buffer */
293
294 /* Method for the receiver side */
295 void (*receive)(struct gsm_mux *gsm, u8 ch);
296
297 /* Link Layer */
298 unsigned int mru;
299 unsigned int mtu;
300 int initiator; /* Did we initiate connection */
301 bool dead; /* Has the mux been shut down */
302 struct gsm_dlci *dlci[NUM_DLCI];
303 int old_c_iflag; /* termios c_iflag value before attach */
304 bool constipated; /* Asked by remote to shut up */
305 bool has_devices; /* Devices were registered */
306
307 spinlock_t tx_lock;
308 unsigned int tx_bytes; /* TX data outstanding */
309#define TX_THRESH_HI 8192
310#define TX_THRESH_LO 2048
311 struct list_head tx_ctrl_list; /* Pending control packets */
312 struct list_head tx_data_list; /* Pending data packets */
313
314 /* Control messages */
315 struct timer_list kick_timer; /* Kick TX queuing on timeout */
316 struct timer_list t2_timer; /* Retransmit timer for commands */
317 int cretries; /* Command retry counter */
318 struct gsm_control *pending_cmd;/* Our current pending command */
319 spinlock_t control_lock; /* Protects the pending command */
320
321 /* Configuration */
322 int adaption; /* 1 or 2 supported */
323 u8 ftype; /* UI or UIH */
324 int t1, t2; /* Timers in 1/100th of a sec */
325 unsigned int t3; /* Power wake-up timer in seconds. */
326 int n2; /* Retry count */
327 u8 k; /* Window size */
328
329 /* Statistics (not currently exposed) */
330 unsigned long bad_fcs;
331 unsigned long malformed;
332 unsigned long io_error;
333 unsigned long bad_size;
334 unsigned long unsupported;
335};
336
337
338/*
339 * Mux objects - needed so that we can translate a tty index into the
340 * relevant mux and DLCI.
341 */
342
343#define MAX_MUX 4 /* 256 minors */
344static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
345static DEFINE_SPINLOCK(gsm_mux_lock);
346
347static struct tty_driver *gsm_tty_driver;
348
349/*
350 * This section of the driver logic implements the GSM encodings
351 * both the basic and the 'advanced'. Reliable transport is not
352 * supported.
353 */
354
355#define CR 0x02
356#define EA 0x01
357#define PF 0x10
358
359/* I is special: the rest are ..*/
360#define RR 0x01
361#define UI 0x03
362#define RNR 0x05
363#define REJ 0x09
364#define DM 0x0F
365#define SABM 0x2F
366#define DISC 0x43
367#define UA 0x63
368#define UIH 0xEF
369
370/* Channel commands */
371#define CMD_NSC 0x09
372#define CMD_TEST 0x11
373#define CMD_PSC 0x21
374#define CMD_RLS 0x29
375#define CMD_FCOFF 0x31
376#define CMD_PN 0x41
377#define CMD_RPN 0x49
378#define CMD_FCON 0x51
379#define CMD_CLD 0x61
380#define CMD_SNC 0x69
381#define CMD_MSC 0x71
382
383/* Virtual modem bits */
384#define MDM_FC 0x01
385#define MDM_RTC 0x02
386#define MDM_RTR 0x04
387#define MDM_IC 0x20
388#define MDM_DV 0x40
389
390#define GSM0_SOF 0xF9
391#define GSM1_SOF 0x7E
392#define GSM1_ESCAPE 0x7D
393#define GSM1_ESCAPE_BITS 0x20
394#define XON 0x11
395#define XOFF 0x13
396#define ISO_IEC_646_MASK 0x7F
397
398static const struct tty_port_operations gsm_port_ops;
399
400/*
401 * CRC table for GSM 0710
402 */
403
404static const u8 gsm_fcs8[256] = {
405 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
406 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
407 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
408 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
409 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
410 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
411 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
412 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
413 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
414 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
415 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
416 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
417 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
418 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
419 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
420 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
421 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
422 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
423 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
424 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
425 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
426 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
427 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
428 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
429 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
430 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
431 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
432 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
433 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
434 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
435 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
436 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
437};
438
439#define INIT_FCS 0xFF
440#define GOOD_FCS 0xCF
441
442static void gsm_dlci_close(struct gsm_dlci *dlci);
443static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len);
444static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk);
445static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
446 u8 ctrl);
447static int gsm_send_packet(struct gsm_mux *gsm, struct gsm_msg *msg);
448static void gsmld_write_trigger(struct gsm_mux *gsm);
449static void gsmld_write_task(struct work_struct *work);
450
451/**
452 * gsm_fcs_add - update FCS
453 * @fcs: Current FCS
454 * @c: Next data
455 *
456 * Update the FCS to include c. Uses the algorithm in the specification
457 * notes.
458 */
459
460static inline u8 gsm_fcs_add(u8 fcs, u8 c)
461{
462 return gsm_fcs8[fcs ^ c];
463}
464
465/**
466 * gsm_fcs_add_block - update FCS for a block
467 * @fcs: Current FCS
468 * @c: buffer of data
469 * @len: length of buffer
470 *
471 * Update the FCS to include c. Uses the algorithm in the specification
472 * notes.
473 */
474
475static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
476{
477 while (len--)
478 fcs = gsm_fcs8[fcs ^ *c++];
479 return fcs;
480}
481
482/**
483 * gsm_read_ea - read a byte into an EA
484 * @val: variable holding value
485 * @c: byte going into the EA
486 *
487 * Processes one byte of an EA. Updates the passed variable
488 * and returns 1 if the EA is now completely read
489 */
490
491static int gsm_read_ea(unsigned int *val, u8 c)
492{
493 /* Add the next 7 bits into the value */
494 *val <<= 7;
495 *val |= c >> 1;
496 /* Was this the last byte of the EA 1 = yes*/
497 return c & EA;
498}
499
500/**
501 * gsm_read_ea_val - read a value until EA
502 * @val: variable holding value
503 * @data: buffer of data
504 * @dlen: length of data
505 *
506 * Processes an EA value. Updates the passed variable and
507 * returns the processed data length.
508 */
509static unsigned int gsm_read_ea_val(unsigned int *val, const u8 *data, int dlen)
510{
511 unsigned int len = 0;
512
513 for (; dlen > 0; dlen--) {
514 len++;
515 if (gsm_read_ea(val, *data++))
516 break;
517 }
518 return len;
519}
520
521/**
522 * gsm_encode_modem - encode modem data bits
523 * @dlci: DLCI to encode from
524 *
525 * Returns the correct GSM encoded modem status bits (6 bit field) for
526 * the current status of the DLCI and attached tty object
527 */
528
529static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
530{
531 u8 modembits = 0;
532 /* FC is true flow control not modem bits */
533 if (dlci->throttled)
534 modembits |= MDM_FC;
535 if (dlci->modem_tx & TIOCM_DTR)
536 modembits |= MDM_RTC;
537 if (dlci->modem_tx & TIOCM_RTS)
538 modembits |= MDM_RTR;
539 if (dlci->modem_tx & TIOCM_RI)
540 modembits |= MDM_IC;
541 if (dlci->modem_tx & TIOCM_CD || dlci->gsm->initiator)
542 modembits |= MDM_DV;
543 return modembits;
544}
545
546static void gsm_hex_dump_bytes(const char *fname, const u8 *data,
547 unsigned long len)
548{
549 char *prefix;
550
551 if (!fname) {
552 print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, 16, 1, data, len,
553 true);
554 return;
555 }
556
557 prefix = kasprintf(GFP_ATOMIC, "%s: ", fname);
558 if (!prefix)
559 return;
560 print_hex_dump(KERN_INFO, prefix, DUMP_PREFIX_OFFSET, 16, 1, data, len,
561 true);
562 kfree(prefix);
563}
564
565/**
566 * gsm_encode_params - encode DLCI parameters
567 * @dlci: DLCI to encode from
568 * @params: buffer to fill with the encoded parameters
569 *
570 * Encodes the parameters according to GSM 07.10 section 5.4.6.3.1
571 * table 3.
572 */
573static int gsm_encode_params(const struct gsm_dlci *dlci,
574 struct gsm_dlci_param_bits *params)
575{
576 const struct gsm_mux *gsm = dlci->gsm;
577 unsigned int i, cl;
578
579 switch (dlci->ftype) {
580 case UIH:
581 i = 0; /* UIH */
582 break;
583 case UI:
584 i = 1; /* UI */
585 break;
586 default:
587 pr_debug("unsupported frame type %d\n", dlci->ftype);
588 return -EINVAL;
589 }
590
591 switch (dlci->adaption) {
592 case 1: /* Unstructured */
593 cl = 0; /* convergence layer type 1 */
594 break;
595 case 2: /* Unstructured with modem bits. */
596 cl = 1; /* convergence layer type 2 */
597 break;
598 default:
599 pr_debug("unsupported adaption %d\n", dlci->adaption);
600 return -EINVAL;
601 }
602
603 params->d_bits = FIELD_PREP(PN_D_FIELD_DLCI, dlci->addr);
604 /* UIH, convergence layer type 1 */
605 params->i_cl_bits = FIELD_PREP(PN_I_CL_FIELD_FTYPE, i) |
606 FIELD_PREP(PN_I_CL_FIELD_ADAPTION, cl);
607 params->p_bits = FIELD_PREP(PN_P_FIELD_PRIO, dlci->prio);
608 params->t_bits = FIELD_PREP(PN_T_FIELD_T1, gsm->t1);
609 params->n_bits = cpu_to_le16(FIELD_PREP(PN_N_FIELD_N1, dlci->mtu));
610 params->na_bits = FIELD_PREP(PN_NA_FIELD_N2, gsm->n2);
611 params->k_bits = FIELD_PREP(PN_K_FIELD_K, dlci->k);
612
613 return 0;
614}
615
616/**
617 * gsm_register_devices - register all tty devices for a given mux index
618 *
619 * @driver: the tty driver that describes the tty devices
620 * @index: the mux number is used to calculate the minor numbers of the
621 * ttys for this mux and may differ from the position in the
622 * mux array.
623 */
624static int gsm_register_devices(struct tty_driver *driver, unsigned int index)
625{
626 struct device *dev;
627 int i;
628 unsigned int base;
629
630 if (!driver || index >= MAX_MUX)
631 return -EINVAL;
632
633 base = index * NUM_DLCI; /* first minor for this index */
634 for (i = 1; i < NUM_DLCI; i++) {
635 /* Don't register device 0 - this is the control channel
636 * and not a usable tty interface
637 */
638 dev = tty_register_device(gsm_tty_driver, base + i, NULL);
639 if (IS_ERR(dev)) {
640 if (debug & DBG_ERRORS)
641 pr_info("%s failed to register device minor %u",
642 __func__, base + i);
643 for (i--; i >= 1; i--)
644 tty_unregister_device(gsm_tty_driver, base + i);
645 return PTR_ERR(dev);
646 }
647 }
648
649 return 0;
650}
651
652/**
653 * gsm_unregister_devices - unregister all tty devices for a given mux index
654 *
655 * @driver: the tty driver that describes the tty devices
656 * @index: the mux number is used to calculate the minor numbers of the
657 * ttys for this mux and may differ from the position in the
658 * mux array.
659 */
660static void gsm_unregister_devices(struct tty_driver *driver,
661 unsigned int index)
662{
663 int i;
664 unsigned int base;
665
666 if (!driver || index >= MAX_MUX)
667 return;
668
669 base = index * NUM_DLCI; /* first minor for this index */
670 for (i = 1; i < NUM_DLCI; i++) {
671 /* Don't unregister device 0 - this is the control
672 * channel and not a usable tty interface
673 */
674 tty_unregister_device(gsm_tty_driver, base + i);
675 }
676}
677
678/**
679 * gsm_print_packet - display a frame for debug
680 * @hdr: header to print before decode
681 * @addr: address EA from the frame
682 * @cr: C/R bit seen as initiator
683 * @control: control including PF bit
684 * @data: following data bytes
685 * @dlen: length of data
686 *
687 * Displays a packet in human readable format for debugging purposes. The
688 * style is based on amateur radio LAP-B dump display.
689 */
690
691static void gsm_print_packet(const char *hdr, int addr, int cr,
692 u8 control, const u8 *data, int dlen)
693{
694 if (!(debug & DBG_DUMP))
695 return;
696 /* Only show user payload frames if debug & DBG_PAYLOAD */
697 if (!(debug & DBG_PAYLOAD) && addr != 0)
698 if ((control & ~PF) == UI || (control & ~PF) == UIH)
699 return;
700
701 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
702
703 switch (control & ~PF) {
704 case SABM:
705 pr_cont("SABM");
706 break;
707 case UA:
708 pr_cont("UA");
709 break;
710 case DISC:
711 pr_cont("DISC");
712 break;
713 case DM:
714 pr_cont("DM");
715 break;
716 case UI:
717 pr_cont("UI");
718 break;
719 case UIH:
720 pr_cont("UIH");
721 break;
722 default:
723 if (!(control & 0x01)) {
724 pr_cont("I N(S)%d N(R)%d",
725 (control & 0x0E) >> 1, (control & 0xE0) >> 5);
726 } else switch (control & 0x0F) {
727 case RR:
728 pr_cont("RR(%d)", (control & 0xE0) >> 5);
729 break;
730 case RNR:
731 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
732 break;
733 case REJ:
734 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
735 break;
736 default:
737 pr_cont("[%02X]", control);
738 }
739 }
740
741 if (control & PF)
742 pr_cont("(P)");
743 else
744 pr_cont("(F)");
745
746 gsm_hex_dump_bytes(NULL, data, dlen);
747}
748
749
750/*
751 * Link level transmission side
752 */
753
754/**
755 * gsm_stuff_frame - bytestuff a packet
756 * @input: input buffer
757 * @output: output buffer
758 * @len: length of input
759 *
760 * Expand a buffer by bytestuffing it. The worst case size change
761 * is doubling and the caller is responsible for handing out
762 * suitable sized buffers.
763 */
764
765static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
766{
767 int olen = 0;
768 while (len--) {
769 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
770 || (*input & ISO_IEC_646_MASK) == XON
771 || (*input & ISO_IEC_646_MASK) == XOFF) {
772 *output++ = GSM1_ESCAPE;
773 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
774 olen++;
775 } else
776 *output++ = *input++;
777 olen++;
778 }
779 return olen;
780}
781
782/**
783 * gsm_send - send a control frame
784 * @gsm: our GSM mux
785 * @addr: address for control frame
786 * @cr: command/response bit seen as initiator
787 * @control: control byte including PF bit
788 *
789 * Format up and transmit a control frame. These should be transmitted
790 * ahead of data when they are needed.
791 */
792static int gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
793{
794 struct gsm_msg *msg;
795 u8 *dp;
796 int ocr;
797 unsigned long flags;
798
799 msg = gsm_data_alloc(gsm, addr, 0, control);
800 if (!msg)
801 return -ENOMEM;
802
803 /* toggle C/R coding if not initiator */
804 ocr = cr ^ (gsm->initiator ? 0 : 1);
805
806 msg->data -= 3;
807 dp = msg->data;
808 *dp++ = (addr << 2) | (ocr << 1) | EA;
809 *dp++ = control;
810
811 if (gsm->encoding == GSM_BASIC_OPT)
812 *dp++ = EA; /* Length of data = 0 */
813
814 *dp = 0xFF - gsm_fcs_add_block(INIT_FCS, msg->data, dp - msg->data);
815 msg->len = (dp - msg->data) + 1;
816
817 gsm_print_packet("Q->", addr, cr, control, NULL, 0);
818
819 spin_lock_irqsave(&gsm->tx_lock, flags);
820 list_add_tail(&msg->list, &gsm->tx_ctrl_list);
821 gsm->tx_bytes += msg->len;
822 spin_unlock_irqrestore(&gsm->tx_lock, flags);
823 gsmld_write_trigger(gsm);
824
825 return 0;
826}
827
828/**
829 * gsm_dlci_clear_queues - remove outstanding data for a DLCI
830 * @gsm: mux
831 * @dlci: clear for this DLCI
832 *
833 * Clears the data queues for a given DLCI.
834 */
835static void gsm_dlci_clear_queues(struct gsm_mux *gsm, struct gsm_dlci *dlci)
836{
837 struct gsm_msg *msg, *nmsg;
838 int addr = dlci->addr;
839 unsigned long flags;
840
841 /* Clear DLCI write fifo first */
842 spin_lock_irqsave(&dlci->lock, flags);
843 kfifo_reset(&dlci->fifo);
844 spin_unlock_irqrestore(&dlci->lock, flags);
845
846 /* Clear data packets in MUX write queue */
847 spin_lock_irqsave(&gsm->tx_lock, flags);
848 list_for_each_entry_safe(msg, nmsg, &gsm->tx_data_list, list) {
849 if (msg->addr != addr)
850 continue;
851 gsm->tx_bytes -= msg->len;
852 list_del(&msg->list);
853 kfree(msg);
854 }
855 spin_unlock_irqrestore(&gsm->tx_lock, flags);
856}
857
858/**
859 * gsm_response - send a control response
860 * @gsm: our GSM mux
861 * @addr: address for control frame
862 * @control: control byte including PF bit
863 *
864 * Format up and transmit a link level response frame.
865 */
866
867static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
868{
869 gsm_send(gsm, addr, 0, control);
870}
871
872/**
873 * gsm_command - send a control command
874 * @gsm: our GSM mux
875 * @addr: address for control frame
876 * @control: control byte including PF bit
877 *
878 * Format up and transmit a link level command frame.
879 */
880
881static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
882{
883 gsm_send(gsm, addr, 1, control);
884}
885
886/* Data transmission */
887
888#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
889
890/**
891 * gsm_data_alloc - allocate data frame
892 * @gsm: GSM mux
893 * @addr: DLCI address
894 * @len: length excluding header and FCS
895 * @ctrl: control byte
896 *
897 * Allocate a new data buffer for sending frames with data. Space is left
898 * at the front for header bytes but that is treated as an implementation
899 * detail and not for the high level code to use
900 */
901
902static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
903 u8 ctrl)
904{
905 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
906 GFP_ATOMIC);
907 if (m == NULL)
908 return NULL;
909 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
910 m->len = len;
911 m->addr = addr;
912 m->ctrl = ctrl;
913 INIT_LIST_HEAD(&m->list);
914 return m;
915}
916
917/**
918 * gsm_send_packet - sends a single packet
919 * @gsm: GSM Mux
920 * @msg: packet to send
921 *
922 * The given packet is encoded and sent out. No memory is freed.
923 * The caller must hold the gsm tx lock.
924 */
925static int gsm_send_packet(struct gsm_mux *gsm, struct gsm_msg *msg)
926{
927 int len, ret;
928
929
930 if (gsm->encoding == GSM_BASIC_OPT) {
931 gsm->txframe[0] = GSM0_SOF;
932 memcpy(gsm->txframe + 1, msg->data, msg->len);
933 gsm->txframe[msg->len + 1] = GSM0_SOF;
934 len = msg->len + 2;
935 } else {
936 gsm->txframe[0] = GSM1_SOF;
937 len = gsm_stuff_frame(msg->data, gsm->txframe + 1, msg->len);
938 gsm->txframe[len + 1] = GSM1_SOF;
939 len += 2;
940 }
941
942 if (debug & DBG_DATA)
943 gsm_hex_dump_bytes(__func__, gsm->txframe, len);
944 gsm_print_packet("-->", msg->addr, gsm->initiator, msg->ctrl, msg->data,
945 msg->len);
946
947 ret = gsmld_output(gsm, gsm->txframe, len);
948 if (ret <= 0)
949 return ret;
950 /* FIXME: Can eliminate one SOF in many more cases */
951 gsm->tx_bytes -= msg->len;
952
953 return 0;
954}
955
956/**
957 * gsm_is_flow_ctrl_msg - checks if flow control message
958 * @msg: message to check
959 *
960 * Returns true if the given message is a flow control command of the
961 * control channel. False is returned in any other case.
962 */
963static bool gsm_is_flow_ctrl_msg(struct gsm_msg *msg)
964{
965 unsigned int cmd;
966
967 if (msg->addr > 0)
968 return false;
969
970 switch (msg->ctrl & ~PF) {
971 case UI:
972 case UIH:
973 cmd = 0;
974 if (gsm_read_ea_val(&cmd, msg->data + 2, msg->len - 2) < 1)
975 break;
976 switch (cmd & ~PF) {
977 case CMD_FCOFF:
978 case CMD_FCON:
979 return true;
980 }
981 break;
982 }
983
984 return false;
985}
986
987/**
988 * gsm_data_kick - poke the queue
989 * @gsm: GSM Mux
990 *
991 * The tty device has called us to indicate that room has appeared in
992 * the transmit queue. Ram more data into the pipe if we have any.
993 * If we have been flow-stopped by a CMD_FCOFF, then we can only
994 * send messages on DLCI0 until CMD_FCON. The caller must hold
995 * the gsm tx lock.
996 */
997static int gsm_data_kick(struct gsm_mux *gsm)
998{
999 struct gsm_msg *msg, *nmsg;
1000 struct gsm_dlci *dlci;
1001 int ret;
1002
1003 clear_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
1004
1005 /* Serialize control messages and control channel messages first */
1006 list_for_each_entry_safe(msg, nmsg, &gsm->tx_ctrl_list, list) {
1007 if (gsm->constipated && !gsm_is_flow_ctrl_msg(msg))
1008 continue;
1009 ret = gsm_send_packet(gsm, msg);
1010 switch (ret) {
1011 case -ENOSPC:
1012 return -ENOSPC;
1013 case -ENODEV:
1014 /* ldisc not open */
1015 gsm->tx_bytes -= msg->len;
1016 list_del(&msg->list);
1017 kfree(msg);
1018 continue;
1019 default:
1020 if (ret >= 0) {
1021 list_del(&msg->list);
1022 kfree(msg);
1023 }
1024 break;
1025 }
1026 }
1027
1028 if (gsm->constipated)
1029 return -EAGAIN;
1030
1031 /* Serialize other channels */
1032 if (list_empty(&gsm->tx_data_list))
1033 return 0;
1034 list_for_each_entry_safe(msg, nmsg, &gsm->tx_data_list, list) {
1035 dlci = gsm->dlci[msg->addr];
1036 /* Send only messages for DLCIs with valid state */
1037 if (dlci->state != DLCI_OPEN) {
1038 gsm->tx_bytes -= msg->len;
1039 list_del(&msg->list);
1040 kfree(msg);
1041 continue;
1042 }
1043 ret = gsm_send_packet(gsm, msg);
1044 switch (ret) {
1045 case -ENOSPC:
1046 return -ENOSPC;
1047 case -ENODEV:
1048 /* ldisc not open */
1049 gsm->tx_bytes -= msg->len;
1050 list_del(&msg->list);
1051 kfree(msg);
1052 continue;
1053 default:
1054 if (ret >= 0) {
1055 list_del(&msg->list);
1056 kfree(msg);
1057 }
1058 break;
1059 }
1060 }
1061
1062 return 1;
1063}
1064
1065/**
1066 * __gsm_data_queue - queue a UI or UIH frame
1067 * @dlci: DLCI sending the data
1068 * @msg: message queued
1069 *
1070 * Add data to the transmit queue and try and get stuff moving
1071 * out of the mux tty if not already doing so. The Caller must hold
1072 * the gsm tx lock.
1073 */
1074
1075static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
1076{
1077 struct gsm_mux *gsm = dlci->gsm;
1078 u8 *dp = msg->data;
1079 u8 *fcs = dp + msg->len;
1080
1081 /* Fill in the header */
1082 if (gsm->encoding == GSM_BASIC_OPT) {
1083 if (msg->len < 128)
1084 *--dp = (msg->len << 1) | EA;
1085 else {
1086 *--dp = (msg->len >> 7); /* bits 7 - 15 */
1087 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
1088 }
1089 }
1090
1091 *--dp = msg->ctrl;
1092 if (gsm->initiator)
1093 *--dp = (msg->addr << 2) | CR | EA;
1094 else
1095 *--dp = (msg->addr << 2) | EA;
1096 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
1097 /* Ugly protocol layering violation */
1098 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
1099 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
1100 *fcs = 0xFF - *fcs;
1101
1102 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
1103 msg->data, msg->len);
1104
1105 /* Move the header back and adjust the length, also allow for the FCS
1106 now tacked on the end */
1107 msg->len += (msg->data - dp) + 1;
1108 msg->data = dp;
1109
1110 /* Add to the actual output queue */
1111 switch (msg->ctrl & ~PF) {
1112 case UI:
1113 case UIH:
1114 if (msg->addr > 0) {
1115 list_add_tail(&msg->list, &gsm->tx_data_list);
1116 break;
1117 }
1118 fallthrough;
1119 default:
1120 list_add_tail(&msg->list, &gsm->tx_ctrl_list);
1121 break;
1122 }
1123 gsm->tx_bytes += msg->len;
1124
1125 gsmld_write_trigger(gsm);
1126 mod_timer(&gsm->kick_timer, jiffies + 10 * gsm->t1 * HZ / 100);
1127}
1128
1129/**
1130 * gsm_data_queue - queue a UI or UIH frame
1131 * @dlci: DLCI sending the data
1132 * @msg: message queued
1133 *
1134 * Add data to the transmit queue and try and get stuff moving
1135 * out of the mux tty if not already doing so. Take the
1136 * the gsm tx lock and dlci lock.
1137 */
1138
1139static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
1140{
1141 unsigned long flags;
1142 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
1143 __gsm_data_queue(dlci, msg);
1144 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
1145}
1146
1147/**
1148 * gsm_dlci_data_output - try and push data out of a DLCI
1149 * @gsm: mux
1150 * @dlci: the DLCI to pull data from
1151 *
1152 * Pull data from a DLCI and send it into the transmit queue if there
1153 * is data. Keep to the MRU of the mux. This path handles the usual tty
1154 * interface which is a byte stream with optional modem data.
1155 *
1156 * Caller must hold the tx_lock of the mux.
1157 */
1158
1159static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
1160{
1161 struct gsm_msg *msg;
1162 u8 *dp;
1163 int h, len, size;
1164
1165 /* for modem bits without break data */
1166 h = ((dlci->adaption == 1) ? 0 : 1);
1167
1168 len = kfifo_len(&dlci->fifo);
1169 if (len == 0)
1170 return 0;
1171
1172 /* MTU/MRU count only the data bits but watch adaption mode */
1173 if ((len + h) > dlci->mtu)
1174 len = dlci->mtu - h;
1175
1176 size = len + h;
1177
1178 msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype);
1179 if (!msg)
1180 return -ENOMEM;
1181 dp = msg->data;
1182 switch (dlci->adaption) {
1183 case 1: /* Unstructured */
1184 break;
1185 case 2: /* Unstructured with modem bits.
1186 * Always one byte as we never send inline break data
1187 */
1188 *dp++ = (gsm_encode_modem(dlci) << 1) | EA;
1189 break;
1190 default:
1191 pr_err("%s: unsupported adaption %d\n", __func__,
1192 dlci->adaption);
1193 break;
1194 }
1195
1196 WARN_ON(len != kfifo_out_locked(&dlci->fifo, dp, len,
1197 &dlci->lock));
1198
1199 /* Notify upper layer about available send space. */
1200 tty_port_tty_wakeup(&dlci->port);
1201
1202 __gsm_data_queue(dlci, msg);
1203 /* Bytes of data we used up */
1204 return size;
1205}
1206
1207/**
1208 * gsm_dlci_data_output_framed - try and push data out of a DLCI
1209 * @gsm: mux
1210 * @dlci: the DLCI to pull data from
1211 *
1212 * Pull data from a DLCI and send it into the transmit queue if there
1213 * is data. Keep to the MRU of the mux. This path handles framed data
1214 * queued as skbuffs to the DLCI.
1215 *
1216 * Caller must hold the tx_lock of the mux.
1217 */
1218
1219static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
1220 struct gsm_dlci *dlci)
1221{
1222 struct gsm_msg *msg;
1223 u8 *dp;
1224 int len, size;
1225 int last = 0, first = 0;
1226 int overhead = 0;
1227
1228 /* One byte per frame is used for B/F flags */
1229 if (dlci->adaption == 4)
1230 overhead = 1;
1231
1232 /* dlci->skb is locked by tx_lock */
1233 if (dlci->skb == NULL) {
1234 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
1235 if (dlci->skb == NULL)
1236 return 0;
1237 first = 1;
1238 }
1239 len = dlci->skb->len + overhead;
1240
1241 /* MTU/MRU count only the data bits */
1242 if (len > dlci->mtu) {
1243 if (dlci->adaption == 3) {
1244 /* Over long frame, bin it */
1245 dev_kfree_skb_any(dlci->skb);
1246 dlci->skb = NULL;
1247 return 0;
1248 }
1249 len = dlci->mtu;
1250 } else
1251 last = 1;
1252
1253 size = len + overhead;
1254 msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype);
1255 if (msg == NULL) {
1256 skb_queue_tail(&dlci->skb_list, dlci->skb);
1257 dlci->skb = NULL;
1258 return -ENOMEM;
1259 }
1260 dp = msg->data;
1261
1262 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
1263 /* Flag byte to carry the start/end info */
1264 *dp++ = last << 7 | first << 6 | 1; /* EA */
1265 len--;
1266 }
1267 memcpy(dp, dlci->skb->data, len);
1268 skb_pull(dlci->skb, len);
1269 __gsm_data_queue(dlci, msg);
1270 if (last) {
1271 dev_kfree_skb_any(dlci->skb);
1272 dlci->skb = NULL;
1273 }
1274 return size;
1275}
1276
1277/**
1278 * gsm_dlci_modem_output - try and push modem status out of a DLCI
1279 * @gsm: mux
1280 * @dlci: the DLCI to pull modem status from
1281 * @brk: break signal
1282 *
1283 * Push an empty frame in to the transmit queue to update the modem status
1284 * bits and to transmit an optional break.
1285 *
1286 * Caller must hold the tx_lock of the mux.
1287 */
1288
1289static int gsm_dlci_modem_output(struct gsm_mux *gsm, struct gsm_dlci *dlci,
1290 u8 brk)
1291{
1292 u8 *dp = NULL;
1293 struct gsm_msg *msg;
1294 int size = 0;
1295
1296 /* for modem bits without break data */
1297 switch (dlci->adaption) {
1298 case 1: /* Unstructured */
1299 break;
1300 case 2: /* Unstructured with modem bits. */
1301 size++;
1302 if (brk > 0)
1303 size++;
1304 break;
1305 default:
1306 pr_err("%s: unsupported adaption %d\n", __func__,
1307 dlci->adaption);
1308 return -EINVAL;
1309 }
1310
1311 msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype);
1312 if (!msg) {
1313 pr_err("%s: gsm_data_alloc error", __func__);
1314 return -ENOMEM;
1315 }
1316 dp = msg->data;
1317 switch (dlci->adaption) {
1318 case 1: /* Unstructured */
1319 break;
1320 case 2: /* Unstructured with modem bits. */
1321 if (brk == 0) {
1322 *dp++ = (gsm_encode_modem(dlci) << 1) | EA;
1323 } else {
1324 *dp++ = gsm_encode_modem(dlci) << 1;
1325 *dp++ = (brk << 4) | 2 | EA; /* Length, Break, EA */
1326 }
1327 break;
1328 default:
1329 /* Handled above */
1330 break;
1331 }
1332
1333 __gsm_data_queue(dlci, msg);
1334 return size;
1335}
1336
1337/**
1338 * gsm_dlci_data_sweep - look for data to send
1339 * @gsm: the GSM mux
1340 *
1341 * Sweep the GSM mux channels in priority order looking for ones with
1342 * data to send. We could do with optimising this scan a bit. We aim
1343 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
1344 * TX_THRESH_LO we get called again
1345 *
1346 * FIXME: We should round robin between groups and in theory you can
1347 * renegotiate DLCI priorities with optional stuff. Needs optimising.
1348 */
1349
1350static int gsm_dlci_data_sweep(struct gsm_mux *gsm)
1351{
1352 /* Priority ordering: We should do priority with RR of the groups */
1353 int i, len, ret = 0;
1354 bool sent;
1355 struct gsm_dlci *dlci;
1356
1357 while (gsm->tx_bytes < TX_THRESH_HI) {
1358 for (sent = false, i = 1; i < NUM_DLCI; i++) {
1359 dlci = gsm->dlci[i];
1360 /* skip unused or blocked channel */
1361 if (!dlci || dlci->constipated)
1362 continue;
1363 /* skip channels with invalid state */
1364 if (dlci->state != DLCI_OPEN)
1365 continue;
1366 /* count the sent data per adaption */
1367 if (dlci->adaption < 3 && !dlci->net)
1368 len = gsm_dlci_data_output(gsm, dlci);
1369 else
1370 len = gsm_dlci_data_output_framed(gsm, dlci);
1371 /* on error exit */
1372 if (len < 0)
1373 return ret;
1374 if (len > 0) {
1375 ret++;
1376 sent = true;
1377 /* The lower DLCs can starve the higher DLCs! */
1378 break;
1379 }
1380 /* try next */
1381 }
1382 if (!sent)
1383 break;
1384 }
1385
1386 return ret;
1387}
1388
1389/**
1390 * gsm_dlci_data_kick - transmit if possible
1391 * @dlci: DLCI to kick
1392 *
1393 * Transmit data from this DLCI if the queue is empty. We can't rely on
1394 * a tty wakeup except when we filled the pipe so we need to fire off
1395 * new data ourselves in other cases.
1396 */
1397
1398static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
1399{
1400 unsigned long flags;
1401 int sweep;
1402
1403 if (dlci->constipated)
1404 return;
1405
1406 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
1407 /* If we have nothing running then we need to fire up */
1408 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
1409 if (dlci->gsm->tx_bytes == 0) {
1410 if (dlci->net)
1411 gsm_dlci_data_output_framed(dlci->gsm, dlci);
1412 else
1413 gsm_dlci_data_output(dlci->gsm, dlci);
1414 }
1415 if (sweep)
1416 gsm_dlci_data_sweep(dlci->gsm);
1417 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
1418}
1419
1420/*
1421 * Control message processing
1422 */
1423
1424
1425/**
1426 * gsm_control_command - send a command frame to a control
1427 * @gsm: gsm channel
1428 * @cmd: the command to use
1429 * @data: data to follow encoded info
1430 * @dlen: length of data
1431 *
1432 * Encode up and queue a UI/UIH frame containing our command.
1433 */
1434static int gsm_control_command(struct gsm_mux *gsm, int cmd, const u8 *data,
1435 int dlen)
1436{
1437 struct gsm_msg *msg;
1438
1439 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->dlci[0]->ftype);
1440 if (msg == NULL)
1441 return -ENOMEM;
1442
1443 msg->data[0] = (cmd << 1) | CR | EA; /* Set C/R */
1444 msg->data[1] = (dlen << 1) | EA;
1445 memcpy(msg->data + 2, data, dlen);
1446 gsm_data_queue(gsm->dlci[0], msg);
1447
1448 return 0;
1449}
1450
1451/**
1452 * gsm_control_reply - send a response frame to a control
1453 * @gsm: gsm channel
1454 * @cmd: the command to use
1455 * @data: data to follow encoded info
1456 * @dlen: length of data
1457 *
1458 * Encode up and queue a UI/UIH frame containing our response.
1459 */
1460
1461static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data,
1462 int dlen)
1463{
1464 struct gsm_msg *msg;
1465
1466 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->dlci[0]->ftype);
1467 if (msg == NULL)
1468 return;
1469 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1470 msg->data[1] = (dlen << 1) | EA;
1471 memcpy(msg->data + 2, data, dlen);
1472 gsm_data_queue(gsm->dlci[0], msg);
1473}
1474
1475/**
1476 * gsm_process_modem - process received modem status
1477 * @tty: virtual tty bound to the DLCI
1478 * @dlci: DLCI to affect
1479 * @modem: modem bits (full EA)
1480 * @slen: number of signal octets
1481 *
1482 * Used when a modem control message or line state inline in adaption
1483 * layer 2 is processed. Sort out the local modem state and throttles
1484 */
1485
1486static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1487 u32 modem, int slen)
1488{
1489 int mlines = 0;
1490 u8 brk = 0;
1491 int fc;
1492
1493 /* The modem status command can either contain one octet (V.24 signals)
1494 * or two octets (V.24 signals + break signals). This is specified in
1495 * section 5.4.6.3.7 of the 07.10 mux spec.
1496 */
1497
1498 if (slen == 1)
1499 modem = modem & 0x7f;
1500 else {
1501 brk = modem & 0x7f;
1502 modem = (modem >> 7) & 0x7f;
1503 }
1504
1505 /* Flow control/ready to communicate */
1506 fc = (modem & MDM_FC) || !(modem & MDM_RTR);
1507 if (fc && !dlci->constipated) {
1508 /* Need to throttle our output on this device */
1509 dlci->constipated = true;
1510 } else if (!fc && dlci->constipated) {
1511 dlci->constipated = false;
1512 gsm_dlci_data_kick(dlci);
1513 }
1514
1515 /* Map modem bits */
1516 if (modem & MDM_RTC)
1517 mlines |= TIOCM_DSR | TIOCM_DTR;
1518 if (modem & MDM_RTR)
1519 mlines |= TIOCM_RTS | TIOCM_CTS;
1520 if (modem & MDM_IC)
1521 mlines |= TIOCM_RI;
1522 if (modem & MDM_DV)
1523 mlines |= TIOCM_CD;
1524
1525 /* Carrier drop -> hangup */
1526 if (tty) {
1527 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1528 if (!C_CLOCAL(tty))
1529 tty_hangup(tty);
1530 }
1531 if (brk & 0x01)
1532 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
1533 dlci->modem_rx = mlines;
1534}
1535
1536/**
1537 * gsm_process_negotiation - process received parameters
1538 * @gsm: GSM channel
1539 * @addr: DLCI address
1540 * @cr: command/response
1541 * @params: encoded parameters from the parameter negotiation message
1542 *
1543 * Used when the response for our parameter negotiation command was
1544 * received.
1545 */
1546static int gsm_process_negotiation(struct gsm_mux *gsm, unsigned int addr,
1547 unsigned int cr,
1548 const struct gsm_dlci_param_bits *params)
1549{
1550 struct gsm_dlci *dlci = gsm->dlci[addr];
1551 unsigned int ftype, i, adaption, prio, n1, k;
1552
1553 i = FIELD_GET(PN_I_CL_FIELD_FTYPE, params->i_cl_bits);
1554 adaption = FIELD_GET(PN_I_CL_FIELD_ADAPTION, params->i_cl_bits) + 1;
1555 prio = FIELD_GET(PN_P_FIELD_PRIO, params->p_bits);
1556 n1 = FIELD_GET(PN_N_FIELD_N1, get_unaligned_le16(¶ms->n_bits));
1557 k = FIELD_GET(PN_K_FIELD_K, params->k_bits);
1558
1559 if (n1 < MIN_MTU) {
1560 if (debug & DBG_ERRORS)
1561 pr_info("%s N1 out of range in PN\n", __func__);
1562 return -EINVAL;
1563 }
1564
1565 switch (i) {
1566 case 0x00:
1567 ftype = UIH;
1568 break;
1569 case 0x01:
1570 ftype = UI;
1571 break;
1572 case 0x02: /* I frames are not supported */
1573 if (debug & DBG_ERRORS)
1574 pr_info("%s unsupported I frame request in PN\n",
1575 __func__);
1576 return -EINVAL;
1577 default:
1578 if (debug & DBG_ERRORS)
1579 pr_info("%s i out of range in PN\n", __func__);
1580 return -EINVAL;
1581 }
1582
1583 if (!cr && gsm->initiator) {
1584 if (adaption != dlci->adaption) {
1585 if (debug & DBG_ERRORS)
1586 pr_info("%s invalid adaption %d in PN\n",
1587 __func__, adaption);
1588 return -EINVAL;
1589 }
1590 if (prio != dlci->prio) {
1591 if (debug & DBG_ERRORS)
1592 pr_info("%s invalid priority %d in PN",
1593 __func__, prio);
1594 return -EINVAL;
1595 }
1596 if (n1 > gsm->mru || n1 > dlci->mtu) {
1597 /* We requested a frame size but the other party wants
1598 * to send larger frames. The standard allows only a
1599 * smaller response value than requested (5.4.6.3.1).
1600 */
1601 if (debug & DBG_ERRORS)
1602 pr_info("%s invalid N1 %d in PN\n", __func__,
1603 n1);
1604 return -EINVAL;
1605 }
1606 dlci->mtu = n1;
1607 if (ftype != dlci->ftype) {
1608 if (debug & DBG_ERRORS)
1609 pr_info("%s invalid i %d in PN\n", __func__, i);
1610 return -EINVAL;
1611 }
1612 if (ftype != UI && ftype != UIH && k > dlci->k) {
1613 if (debug & DBG_ERRORS)
1614 pr_info("%s invalid k %d in PN\n", __func__, k);
1615 return -EINVAL;
1616 }
1617 dlci->k = k;
1618 } else if (cr && !gsm->initiator) {
1619 /* Only convergence layer type 1 and 2 are supported. */
1620 if (adaption != 1 && adaption != 2) {
1621 if (debug & DBG_ERRORS)
1622 pr_info("%s invalid adaption %d in PN\n",
1623 __func__, adaption);
1624 return -EINVAL;
1625 }
1626 dlci->adaption = adaption;
1627 if (n1 > gsm->mru) {
1628 /* Propose a smaller value */
1629 dlci->mtu = gsm->mru;
1630 } else if (n1 > MAX_MTU) {
1631 /* Propose a smaller value */
1632 dlci->mtu = MAX_MTU;
1633 } else {
1634 dlci->mtu = n1;
1635 }
1636 dlci->prio = prio;
1637 dlci->ftype = ftype;
1638 dlci->k = k;
1639 } else {
1640 return -EINVAL;
1641 }
1642
1643 return 0;
1644}
1645
1646/**
1647 * gsm_control_modem - modem status received
1648 * @gsm: GSM channel
1649 * @data: data following command
1650 * @clen: command length
1651 *
1652 * We have received a modem status control message. This is used by
1653 * the GSM mux protocol to pass virtual modem line status and optionally
1654 * to indicate break signals. Unpack it, convert to Linux representation
1655 * and if need be stuff a break message down the tty.
1656 */
1657
1658static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
1659{
1660 unsigned int addr = 0;
1661 unsigned int modem = 0;
1662 struct gsm_dlci *dlci;
1663 int len = clen;
1664 int cl = clen;
1665 const u8 *dp = data;
1666 struct tty_struct *tty;
1667
1668 len = gsm_read_ea_val(&addr, data, cl);
1669 if (len < 1)
1670 return;
1671
1672 addr >>= 1;
1673 /* Closed port, or invalid ? */
1674 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1675 return;
1676 dlci = gsm->dlci[addr];
1677
1678 /* Must be at least one byte following the EA */
1679 if ((cl - len) < 1)
1680 return;
1681
1682 dp += len;
1683 cl -= len;
1684
1685 /* get the modem status */
1686 len = gsm_read_ea_val(&modem, dp, cl);
1687 if (len < 1)
1688 return;
1689
1690 tty = tty_port_tty_get(&dlci->port);
1691 gsm_process_modem(tty, dlci, modem, cl);
1692 if (tty) {
1693 tty_wakeup(tty);
1694 tty_kref_put(tty);
1695 }
1696 gsm_control_reply(gsm, CMD_MSC, data, clen);
1697}
1698
1699/**
1700 * gsm_control_negotiation - parameter negotiation received
1701 * @gsm: GSM channel
1702 * @cr: command/response flag
1703 * @data: data following command
1704 * @dlen: data length
1705 *
1706 * We have received a parameter negotiation message. This is used by
1707 * the GSM mux protocol to configure protocol parameters for a new DLCI.
1708 */
1709static void gsm_control_negotiation(struct gsm_mux *gsm, unsigned int cr,
1710 const u8 *data, unsigned int dlen)
1711{
1712 unsigned int addr;
1713 struct gsm_dlci_param_bits pn_reply;
1714 struct gsm_dlci *dlci;
1715 struct gsm_dlci_param_bits *params;
1716
1717 if (dlen < sizeof(struct gsm_dlci_param_bits))
1718 return;
1719
1720 /* Invalid DLCI? */
1721 params = (struct gsm_dlci_param_bits *)data;
1722 addr = FIELD_GET(PN_D_FIELD_DLCI, params->d_bits);
1723 if (addr == 0 || addr >= NUM_DLCI || !gsm->dlci[addr])
1724 return;
1725 dlci = gsm->dlci[addr];
1726
1727 /* Too late for parameter negotiation? */
1728 if ((!cr && dlci->state == DLCI_OPENING) || dlci->state == DLCI_OPEN)
1729 return;
1730
1731 /* Process the received parameters */
1732 if (gsm_process_negotiation(gsm, addr, cr, params) != 0) {
1733 /* Negotiation failed. Close the link. */
1734 if (debug & DBG_ERRORS)
1735 pr_info("%s PN failed\n", __func__);
1736 gsm_dlci_close(dlci);
1737 return;
1738 }
1739
1740 if (cr) {
1741 /* Reply command with accepted parameters. */
1742 if (gsm_encode_params(dlci, &pn_reply) == 0)
1743 gsm_control_reply(gsm, CMD_PN, (const u8 *)&pn_reply,
1744 sizeof(pn_reply));
1745 else if (debug & DBG_ERRORS)
1746 pr_info("%s PN invalid\n", __func__);
1747 } else if (dlci->state == DLCI_CONFIGURE) {
1748 /* Proceed with link setup by sending SABM before UA */
1749 dlci->state = DLCI_OPENING;
1750 gsm_command(gsm, dlci->addr, SABM|PF);
1751 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1752 } else {
1753 if (debug & DBG_ERRORS)
1754 pr_info("%s PN in invalid state\n", __func__);
1755 }
1756}
1757
1758/**
1759 * gsm_control_rls - remote line status
1760 * @gsm: GSM channel
1761 * @data: data bytes
1762 * @clen: data length
1763 *
1764 * The modem sends us a two byte message on the control channel whenever
1765 * it wishes to send us an error state from the virtual link. Stuff
1766 * this into the uplink tty if present
1767 */
1768
1769static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen)
1770{
1771 struct tty_port *port;
1772 unsigned int addr = 0;
1773 u8 bits;
1774 int len = clen;
1775 const u8 *dp = data;
1776
1777 while (gsm_read_ea(&addr, *dp++) == 0) {
1778 len--;
1779 if (len == 0)
1780 return;
1781 }
1782 /* Must be at least one byte following ea */
1783 len--;
1784 if (len <= 0)
1785 return;
1786 addr >>= 1;
1787 /* Closed port, or invalid ? */
1788 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1789 return;
1790 /* No error ? */
1791 bits = *dp;
1792 if ((bits & 1) == 0)
1793 return;
1794
1795 port = &gsm->dlci[addr]->port;
1796
1797 if (bits & 2)
1798 tty_insert_flip_char(port, 0, TTY_OVERRUN);
1799 if (bits & 4)
1800 tty_insert_flip_char(port, 0, TTY_PARITY);
1801 if (bits & 8)
1802 tty_insert_flip_char(port, 0, TTY_FRAME);
1803
1804 tty_flip_buffer_push(port);
1805
1806 gsm_control_reply(gsm, CMD_RLS, data, clen);
1807}
1808
1809static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1810
1811/**
1812 * gsm_control_message - DLCI 0 control processing
1813 * @gsm: our GSM mux
1814 * @command: the command EA
1815 * @data: data beyond the command/length EAs
1816 * @clen: length
1817 *
1818 * Input processor for control messages from the other end of the link.
1819 * Processes the incoming request and queues a response frame or an
1820 * NSC response if not supported
1821 */
1822
1823static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1824 const u8 *data, int clen)
1825{
1826 u8 buf[1];
1827
1828 switch (command) {
1829 case CMD_CLD: {
1830 struct gsm_dlci *dlci = gsm->dlci[0];
1831 /* Modem wishes to close down */
1832 if (dlci) {
1833 dlci->dead = true;
1834 gsm->dead = true;
1835 gsm_dlci_begin_close(dlci);
1836 }
1837 }
1838 break;
1839 case CMD_TEST:
1840 /* Modem wishes to test, reply with the data */
1841 gsm_control_reply(gsm, CMD_TEST, data, clen);
1842 break;
1843 case CMD_FCON:
1844 /* Modem can accept data again */
1845 gsm->constipated = false;
1846 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1847 /* Kick the link in case it is idling */
1848 gsmld_write_trigger(gsm);
1849 break;
1850 case CMD_FCOFF:
1851 /* Modem wants us to STFU */
1852 gsm->constipated = true;
1853 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1854 break;
1855 case CMD_MSC:
1856 /* Out of band modem line change indicator for a DLCI */
1857 gsm_control_modem(gsm, data, clen);
1858 break;
1859 case CMD_RLS:
1860 /* Out of band error reception for a DLCI */
1861 gsm_control_rls(gsm, data, clen);
1862 break;
1863 case CMD_PSC:
1864 /* Modem wishes to enter power saving state */
1865 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1866 break;
1867 /* Optional commands */
1868 case CMD_PN:
1869 /* Modem sends a parameter negotiation command */
1870 gsm_control_negotiation(gsm, 1, data, clen);
1871 break;
1872 /* Optional unsupported commands */
1873 case CMD_RPN: /* Remote port negotiation */
1874 case CMD_SNC: /* Service negotiation command */
1875 default:
1876 /* Reply to bad commands with an NSC */
1877 buf[0] = command;
1878 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1879 break;
1880 }
1881}
1882
1883/**
1884 * gsm_control_response - process a response to our control
1885 * @gsm: our GSM mux
1886 * @command: the command (response) EA
1887 * @data: data beyond the command/length EA
1888 * @clen: length
1889 *
1890 * Process a response to an outstanding command. We only allow a single
1891 * control message in flight so this is fairly easy. All the clean up
1892 * is done by the caller, we just update the fields, flag it as done
1893 * and return
1894 */
1895
1896static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1897 const u8 *data, int clen)
1898{
1899 struct gsm_control *ctrl;
1900 unsigned long flags;
1901
1902 spin_lock_irqsave(&gsm->control_lock, flags);
1903
1904 ctrl = gsm->pending_cmd;
1905 command |= 1;
1906 /* Does the reply match our command */
1907 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1908 /* Our command was replied to, kill the retry timer */
1909 del_timer(&gsm->t2_timer);
1910 gsm->pending_cmd = NULL;
1911 /* Rejected by the other end */
1912 if (command == CMD_NSC)
1913 ctrl->error = -EOPNOTSUPP;
1914 ctrl->done = 1;
1915 wake_up(&gsm->event);
1916 /* Or did we receive the PN response to our PN command */
1917 } else if (command == CMD_PN) {
1918 gsm_control_negotiation(gsm, 0, data, clen);
1919 }
1920 spin_unlock_irqrestore(&gsm->control_lock, flags);
1921}
1922
1923/**
1924 * gsm_control_transmit - send control packet
1925 * @gsm: gsm mux
1926 * @ctrl: frame to send
1927 *
1928 * Send out a pending control command (called under control lock)
1929 */
1930
1931static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1932{
1933 gsm_control_command(gsm, ctrl->cmd, ctrl->data, ctrl->len);
1934}
1935
1936/**
1937 * gsm_control_retransmit - retransmit a control frame
1938 * @t: timer contained in our gsm object
1939 *
1940 * Called off the T2 timer expiry in order to retransmit control frames
1941 * that have been lost in the system somewhere. The control_lock protects
1942 * us from colliding with another sender or a receive completion event.
1943 * In that situation the timer may still occur in a small window but
1944 * gsm->pending_cmd will be NULL and we just let the timer expire.
1945 */
1946
1947static void gsm_control_retransmit(struct timer_list *t)
1948{
1949 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer);
1950 struct gsm_control *ctrl;
1951 unsigned long flags;
1952 spin_lock_irqsave(&gsm->control_lock, flags);
1953 ctrl = gsm->pending_cmd;
1954 if (ctrl) {
1955 if (gsm->cretries == 0 || !gsm->dlci[0] || gsm->dlci[0]->dead) {
1956 gsm->pending_cmd = NULL;
1957 ctrl->error = -ETIMEDOUT;
1958 ctrl->done = 1;
1959 spin_unlock_irqrestore(&gsm->control_lock, flags);
1960 wake_up(&gsm->event);
1961 return;
1962 }
1963 gsm->cretries--;
1964 gsm_control_transmit(gsm, ctrl);
1965 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1966 }
1967 spin_unlock_irqrestore(&gsm->control_lock, flags);
1968}
1969
1970/**
1971 * gsm_control_send - send a control frame on DLCI 0
1972 * @gsm: the GSM channel
1973 * @command: command to send including CR bit
1974 * @data: bytes of data (must be kmalloced)
1975 * @clen: length of the block to send
1976 *
1977 * Queue and dispatch a control command. Only one command can be
1978 * active at a time. In theory more can be outstanding but the matching
1979 * gets really complicated so for now stick to one outstanding.
1980 */
1981
1982static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1983 unsigned int command, u8 *data, int clen)
1984{
1985 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1986 GFP_ATOMIC);
1987 unsigned long flags;
1988 if (ctrl == NULL)
1989 return NULL;
1990retry:
1991 wait_event(gsm->event, gsm->pending_cmd == NULL);
1992 spin_lock_irqsave(&gsm->control_lock, flags);
1993 if (gsm->pending_cmd != NULL) {
1994 spin_unlock_irqrestore(&gsm->control_lock, flags);
1995 goto retry;
1996 }
1997 ctrl->cmd = command;
1998 ctrl->data = data;
1999 ctrl->len = clen;
2000 gsm->pending_cmd = ctrl;
2001
2002 /* If DLCI0 is in ADM mode skip retries, it won't respond */
2003 if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
2004 gsm->cretries = 0;
2005 else
2006 gsm->cretries = gsm->n2;
2007
2008 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
2009 gsm_control_transmit(gsm, ctrl);
2010 spin_unlock_irqrestore(&gsm->control_lock, flags);
2011 return ctrl;
2012}
2013
2014/**
2015 * gsm_control_wait - wait for a control to finish
2016 * @gsm: GSM mux
2017 * @control: control we are waiting on
2018 *
2019 * Waits for the control to complete or time out. Frees any used
2020 * resources and returns 0 for success, or an error if the remote
2021 * rejected or ignored the request.
2022 */
2023
2024static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
2025{
2026 int err;
2027 wait_event(gsm->event, control->done == 1);
2028 err = control->error;
2029 kfree(control);
2030 return err;
2031}
2032
2033
2034/*
2035 * DLCI level handling: Needs krefs
2036 */
2037
2038/*
2039 * State transitions and timers
2040 */
2041
2042/**
2043 * gsm_dlci_close - a DLCI has closed
2044 * @dlci: DLCI that closed
2045 *
2046 * Perform processing when moving a DLCI into closed state. If there
2047 * is an attached tty this is hung up
2048 */
2049
2050static void gsm_dlci_close(struct gsm_dlci *dlci)
2051{
2052 del_timer(&dlci->t1);
2053 if (debug & DBG_ERRORS)
2054 pr_debug("DLCI %d goes closed.\n", dlci->addr);
2055 dlci->state = DLCI_CLOSED;
2056 /* Prevent us from sending data before the link is up again */
2057 dlci->constipated = true;
2058 if (dlci->addr != 0) {
2059 tty_port_tty_hangup(&dlci->port, false);
2060 gsm_dlci_clear_queues(dlci->gsm, dlci);
2061 /* Ensure that gsmtty_open() can return. */
2062 tty_port_set_initialized(&dlci->port, 0);
2063 wake_up_interruptible(&dlci->port.open_wait);
2064 } else
2065 dlci->gsm->dead = true;
2066 /* A DLCI 0 close is a MUX termination so we need to kick that
2067 back to userspace somehow */
2068 gsm_dlci_data_kick(dlci);
2069 wake_up(&dlci->gsm->event);
2070}
2071
2072/**
2073 * gsm_dlci_open - a DLCI has opened
2074 * @dlci: DLCI that opened
2075 *
2076 * Perform processing when moving a DLCI into open state.
2077 */
2078
2079static void gsm_dlci_open(struct gsm_dlci *dlci)
2080{
2081 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
2082 open -> open */
2083 del_timer(&dlci->t1);
2084 /* This will let a tty open continue */
2085 dlci->state = DLCI_OPEN;
2086 dlci->constipated = false;
2087 if (debug & DBG_ERRORS)
2088 pr_debug("DLCI %d goes open.\n", dlci->addr);
2089 /* Send current modem state */
2090 if (dlci->addr)
2091 gsm_modem_update(dlci, 0);
2092 gsm_dlci_data_kick(dlci);
2093 wake_up(&dlci->gsm->event);
2094}
2095
2096/**
2097 * gsm_dlci_negotiate - start parameter negotiation
2098 * @dlci: DLCI to open
2099 *
2100 * Starts the parameter negotiation for the new DLCI. This needs to be done
2101 * before the DLCI initialized the channel via SABM.
2102 */
2103static int gsm_dlci_negotiate(struct gsm_dlci *dlci)
2104{
2105 struct gsm_mux *gsm = dlci->gsm;
2106 struct gsm_dlci_param_bits params;
2107 int ret;
2108
2109 ret = gsm_encode_params(dlci, ¶ms);
2110 if (ret != 0)
2111 return ret;
2112
2113 /* We cannot asynchronous wait for the command response with
2114 * gsm_command() and gsm_control_wait() at this point.
2115 */
2116 ret = gsm_control_command(gsm, CMD_PN, (const u8 *)¶ms,
2117 sizeof(params));
2118
2119 return ret;
2120}
2121
2122/**
2123 * gsm_dlci_t1 - T1 timer expiry
2124 * @t: timer contained in the DLCI that opened
2125 *
2126 * The T1 timer handles retransmits of control frames (essentially of
2127 * SABM and DISC). We resend the command until the retry count runs out
2128 * in which case an opening port goes back to closed and a closing port
2129 * is simply put into closed state (any further frames from the other
2130 * end will get a DM response)
2131 *
2132 * Some control dlci can stay in ADM mode with other dlci working just
2133 * fine. In that case we can just keep the control dlci open after the
2134 * DLCI_OPENING retries time out.
2135 */
2136
2137static void gsm_dlci_t1(struct timer_list *t)
2138{
2139 struct gsm_dlci *dlci = from_timer(dlci, t, t1);
2140 struct gsm_mux *gsm = dlci->gsm;
2141
2142 switch (dlci->state) {
2143 case DLCI_CONFIGURE:
2144 if (dlci->retries && gsm_dlci_negotiate(dlci) == 0) {
2145 dlci->retries--;
2146 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2147 } else {
2148 gsm_dlci_begin_close(dlci); /* prevent half open link */
2149 }
2150 break;
2151 case DLCI_OPENING:
2152 if (dlci->retries) {
2153 dlci->retries--;
2154 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
2155 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2156 } else if (!dlci->addr && gsm->control == (DM | PF)) {
2157 if (debug & DBG_ERRORS)
2158 pr_info("DLCI %d opening in ADM mode.\n",
2159 dlci->addr);
2160 dlci->mode = DLCI_MODE_ADM;
2161 gsm_dlci_open(dlci);
2162 } else {
2163 gsm_dlci_begin_close(dlci); /* prevent half open link */
2164 }
2165
2166 break;
2167 case DLCI_CLOSING:
2168 if (dlci->retries) {
2169 dlci->retries--;
2170 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
2171 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2172 } else
2173 gsm_dlci_close(dlci);
2174 break;
2175 default:
2176 pr_debug("%s: unhandled state: %d\n", __func__, dlci->state);
2177 break;
2178 }
2179}
2180
2181/**
2182 * gsm_dlci_begin_open - start channel open procedure
2183 * @dlci: DLCI to open
2184 *
2185 * Commence opening a DLCI from the Linux side. We issue SABM messages
2186 * to the modem which should then reply with a UA or ADM, at which point
2187 * we will move into open state. Opening is done asynchronously with retry
2188 * running off timers and the responses.
2189 * Parameter negotiation is performed before SABM if required.
2190 */
2191
2192static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
2193{
2194 struct gsm_mux *gsm = dlci ? dlci->gsm : NULL;
2195 bool need_pn = false;
2196
2197 if (!gsm)
2198 return;
2199
2200 if (dlci->addr != 0) {
2201 if (gsm->adaption != 1 || gsm->adaption != dlci->adaption)
2202 need_pn = true;
2203 if (dlci->prio != (roundup(dlci->addr + 1, 8) - 1))
2204 need_pn = true;
2205 if (gsm->ftype != dlci->ftype)
2206 need_pn = true;
2207 }
2208
2209 switch (dlci->state) {
2210 case DLCI_CLOSED:
2211 case DLCI_CLOSING:
2212 dlci->retries = gsm->n2;
2213 if (!need_pn) {
2214 dlci->state = DLCI_OPENING;
2215 gsm_command(gsm, dlci->addr, SABM|PF);
2216 } else {
2217 /* Configure DLCI before setup */
2218 dlci->state = DLCI_CONFIGURE;
2219 if (gsm_dlci_negotiate(dlci) != 0) {
2220 gsm_dlci_close(dlci);
2221 return;
2222 }
2223 }
2224 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2225 break;
2226 default:
2227 break;
2228 }
2229}
2230
2231/**
2232 * gsm_dlci_set_opening - change state to opening
2233 * @dlci: DLCI to open
2234 *
2235 * Change internal state to wait for DLCI open from initiator side.
2236 * We set off timers and responses upon reception of an SABM.
2237 */
2238static void gsm_dlci_set_opening(struct gsm_dlci *dlci)
2239{
2240 switch (dlci->state) {
2241 case DLCI_CLOSED:
2242 case DLCI_CLOSING:
2243 dlci->state = DLCI_OPENING;
2244 break;
2245 default:
2246 break;
2247 }
2248}
2249
2250/**
2251 * gsm_dlci_begin_close - start channel open procedure
2252 * @dlci: DLCI to open
2253 *
2254 * Commence closing a DLCI from the Linux side. We issue DISC messages
2255 * to the modem which should then reply with a UA, at which point we
2256 * will move into closed state. Closing is done asynchronously with retry
2257 * off timers. We may also receive a DM reply from the other end which
2258 * indicates the channel was already closed.
2259 */
2260
2261static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
2262{
2263 struct gsm_mux *gsm = dlci->gsm;
2264 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
2265 return;
2266 dlci->retries = gsm->n2;
2267 dlci->state = DLCI_CLOSING;
2268 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
2269 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
2270}
2271
2272/**
2273 * gsm_dlci_data - data arrived
2274 * @dlci: channel
2275 * @data: block of bytes received
2276 * @clen: length of received block
2277 *
2278 * A UI or UIH frame has arrived which contains data for a channel
2279 * other than the control channel. If the relevant virtual tty is
2280 * open we shovel the bits down it, if not we drop them.
2281 */
2282
2283static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
2284{
2285 /* krefs .. */
2286 struct tty_port *port = &dlci->port;
2287 struct tty_struct *tty;
2288 unsigned int modem = 0;
2289 int len;
2290
2291 if (debug & DBG_TTY)
2292 pr_debug("%d bytes for tty\n", clen);
2293 switch (dlci->adaption) {
2294 /* Unsupported types */
2295 case 4: /* Packetised interruptible data */
2296 break;
2297 case 3: /* Packetised uininterruptible voice/data */
2298 break;
2299 case 2: /* Asynchronous serial with line state in each frame */
2300 len = gsm_read_ea_val(&modem, data, clen);
2301 if (len < 1)
2302 return;
2303 tty = tty_port_tty_get(port);
2304 if (tty) {
2305 gsm_process_modem(tty, dlci, modem, len);
2306 tty_wakeup(tty);
2307 tty_kref_put(tty);
2308 }
2309 /* Skip processed modem data */
2310 data += len;
2311 clen -= len;
2312 fallthrough;
2313 case 1: /* Line state will go via DLCI 0 controls only */
2314 default:
2315 tty_insert_flip_string(port, data, clen);
2316 tty_flip_buffer_push(port);
2317 }
2318}
2319
2320/**
2321 * gsm_dlci_command - data arrived on control channel
2322 * @dlci: channel
2323 * @data: block of bytes received
2324 * @len: length of received block
2325 *
2326 * A UI or UIH frame has arrived which contains data for DLCI 0 the
2327 * control channel. This should contain a command EA followed by
2328 * control data bytes. The command EA contains a command/response bit
2329 * and we divide up the work accordingly.
2330 */
2331
2332static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
2333{
2334 /* See what command is involved */
2335 unsigned int command = 0;
2336 unsigned int clen = 0;
2337 unsigned int dlen;
2338
2339 /* read the command */
2340 dlen = gsm_read_ea_val(&command, data, len);
2341 len -= dlen;
2342 data += dlen;
2343
2344 /* read any control data */
2345 dlen = gsm_read_ea_val(&clen, data, len);
2346 len -= dlen;
2347 data += dlen;
2348
2349 /* Malformed command? */
2350 if (clen > len)
2351 return;
2352
2353 if (command & 1)
2354 gsm_control_message(dlci->gsm, command, data, clen);
2355 else
2356 gsm_control_response(dlci->gsm, command, data, clen);
2357}
2358
2359/**
2360 * gsm_kick_timer - transmit if possible
2361 * @t: timer contained in our gsm object
2362 *
2363 * Transmit data from DLCIs if the queue is empty. We can't rely on
2364 * a tty wakeup except when we filled the pipe so we need to fire off
2365 * new data ourselves in other cases.
2366 */
2367static void gsm_kick_timer(struct timer_list *t)
2368{
2369 struct gsm_mux *gsm = from_timer(gsm, t, kick_timer);
2370 unsigned long flags;
2371 int sent = 0;
2372
2373 spin_lock_irqsave(&gsm->tx_lock, flags);
2374 /* If we have nothing running then we need to fire up */
2375 if (gsm->tx_bytes < TX_THRESH_LO)
2376 sent = gsm_dlci_data_sweep(gsm);
2377 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2378
2379 if (sent && debug & DBG_DATA)
2380 pr_info("%s TX queue stalled\n", __func__);
2381}
2382
2383/*
2384 * Allocate/Free DLCI channels
2385 */
2386
2387/**
2388 * gsm_dlci_alloc - allocate a DLCI
2389 * @gsm: GSM mux
2390 * @addr: address of the DLCI
2391 *
2392 * Allocate and install a new DLCI object into the GSM mux.
2393 *
2394 * FIXME: review locking races
2395 */
2396
2397static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
2398{
2399 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
2400 if (dlci == NULL)
2401 return NULL;
2402 spin_lock_init(&dlci->lock);
2403 mutex_init(&dlci->mutex);
2404 if (kfifo_alloc(&dlci->fifo, TX_SIZE, GFP_KERNEL) < 0) {
2405 kfree(dlci);
2406 return NULL;
2407 }
2408
2409 skb_queue_head_init(&dlci->skb_list);
2410 timer_setup(&dlci->t1, gsm_dlci_t1, 0);
2411 tty_port_init(&dlci->port);
2412 dlci->port.ops = &gsm_port_ops;
2413 dlci->gsm = gsm;
2414 dlci->addr = addr;
2415 dlci->adaption = gsm->adaption;
2416 dlci->mtu = gsm->mtu;
2417 if (addr == 0)
2418 dlci->prio = 0;
2419 else
2420 dlci->prio = roundup(addr + 1, 8) - 1;
2421 dlci->ftype = gsm->ftype;
2422 dlci->k = gsm->k;
2423 dlci->state = DLCI_CLOSED;
2424 if (addr) {
2425 dlci->data = gsm_dlci_data;
2426 /* Prevent us from sending data before the link is up */
2427 dlci->constipated = true;
2428 } else {
2429 dlci->data = gsm_dlci_command;
2430 }
2431 gsm->dlci[addr] = dlci;
2432 return dlci;
2433}
2434
2435/**
2436 * gsm_dlci_free - free DLCI
2437 * @port: tty port for DLCI to free
2438 *
2439 * Free up a DLCI.
2440 *
2441 * Can sleep.
2442 */
2443static void gsm_dlci_free(struct tty_port *port)
2444{
2445 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2446
2447 timer_shutdown_sync(&dlci->t1);
2448 dlci->gsm->dlci[dlci->addr] = NULL;
2449 kfifo_free(&dlci->fifo);
2450 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
2451 dev_kfree_skb(dlci->skb);
2452 kfree(dlci);
2453}
2454
2455static inline void dlci_get(struct gsm_dlci *dlci)
2456{
2457 tty_port_get(&dlci->port);
2458}
2459
2460static inline void dlci_put(struct gsm_dlci *dlci)
2461{
2462 tty_port_put(&dlci->port);
2463}
2464
2465static void gsm_destroy_network(struct gsm_dlci *dlci);
2466
2467/**
2468 * gsm_dlci_release - release DLCI
2469 * @dlci: DLCI to destroy
2470 *
2471 * Release a DLCI. Actual free is deferred until either
2472 * mux is closed or tty is closed - whichever is last.
2473 *
2474 * Can sleep.
2475 */
2476static void gsm_dlci_release(struct gsm_dlci *dlci)
2477{
2478 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
2479 if (tty) {
2480 mutex_lock(&dlci->mutex);
2481 gsm_destroy_network(dlci);
2482 mutex_unlock(&dlci->mutex);
2483
2484 /* We cannot use tty_hangup() because in tty_kref_put() the tty
2485 * driver assumes that the hangup queue is free and reuses it to
2486 * queue release_one_tty() -> NULL pointer panic in
2487 * process_one_work().
2488 */
2489 tty_vhangup(tty);
2490
2491 tty_port_tty_set(&dlci->port, NULL);
2492 tty_kref_put(tty);
2493 }
2494 dlci->state = DLCI_CLOSED;
2495 dlci_put(dlci);
2496}
2497
2498/*
2499 * LAPBish link layer logic
2500 */
2501
2502/**
2503 * gsm_queue - a GSM frame is ready to process
2504 * @gsm: pointer to our gsm mux
2505 *
2506 * At this point in time a frame has arrived and been demangled from
2507 * the line encoding. All the differences between the encodings have
2508 * been handled below us and the frame is unpacked into the structures.
2509 * The fcs holds the header FCS but any data FCS must be added here.
2510 */
2511
2512static void gsm_queue(struct gsm_mux *gsm)
2513{
2514 struct gsm_dlci *dlci;
2515 u8 cr;
2516 int address;
2517
2518 if (gsm->fcs != GOOD_FCS) {
2519 gsm->bad_fcs++;
2520 if (debug & DBG_DATA)
2521 pr_debug("BAD FCS %02x\n", gsm->fcs);
2522 return;
2523 }
2524 address = gsm->address >> 1;
2525 if (address >= NUM_DLCI)
2526 goto invalid;
2527
2528 cr = gsm->address & 1; /* C/R bit */
2529 cr ^= gsm->initiator ? 0 : 1; /* Flip so 1 always means command */
2530
2531 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
2532
2533 dlci = gsm->dlci[address];
2534
2535 switch (gsm->control) {
2536 case SABM|PF:
2537 if (cr == 1)
2538 goto invalid;
2539 if (dlci == NULL)
2540 dlci = gsm_dlci_alloc(gsm, address);
2541 if (dlci == NULL)
2542 return;
2543 if (dlci->dead)
2544 gsm_response(gsm, address, DM|PF);
2545 else {
2546 gsm_response(gsm, address, UA|PF);
2547 gsm_dlci_open(dlci);
2548 }
2549 break;
2550 case DISC|PF:
2551 if (cr == 1)
2552 goto invalid;
2553 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
2554 gsm_response(gsm, address, DM|PF);
2555 return;
2556 }
2557 /* Real close complete */
2558 gsm_response(gsm, address, UA|PF);
2559 gsm_dlci_close(dlci);
2560 break;
2561 case UA|PF:
2562 if (cr == 0 || dlci == NULL)
2563 break;
2564 switch (dlci->state) {
2565 case DLCI_CLOSING:
2566 gsm_dlci_close(dlci);
2567 break;
2568 case DLCI_OPENING:
2569 gsm_dlci_open(dlci);
2570 break;
2571 default:
2572 pr_debug("%s: unhandled state: %d\n", __func__,
2573 dlci->state);
2574 break;
2575 }
2576 break;
2577 case DM: /* DM can be valid unsolicited */
2578 case DM|PF:
2579 if (cr)
2580 goto invalid;
2581 if (dlci == NULL)
2582 return;
2583 gsm_dlci_close(dlci);
2584 break;
2585 case UI:
2586 case UI|PF:
2587 case UIH:
2588 case UIH|PF:
2589 if (dlci == NULL || dlci->state != DLCI_OPEN) {
2590 gsm_response(gsm, address, DM|PF);
2591 return;
2592 }
2593 dlci->data(dlci, gsm->buf, gsm->len);
2594 break;
2595 default:
2596 goto invalid;
2597 }
2598 return;
2599invalid:
2600 gsm->malformed++;
2601 return;
2602}
2603
2604
2605/**
2606 * gsm0_receive - perform processing for non-transparency
2607 * @gsm: gsm data for this ldisc instance
2608 * @c: character
2609 *
2610 * Receive bytes in gsm mode 0
2611 */
2612
2613static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
2614{
2615 unsigned int len;
2616
2617 switch (gsm->state) {
2618 case GSM_SEARCH: /* SOF marker */
2619 if (c == GSM0_SOF) {
2620 gsm->state = GSM_ADDRESS;
2621 gsm->address = 0;
2622 gsm->len = 0;
2623 gsm->fcs = INIT_FCS;
2624 }
2625 break;
2626 case GSM_ADDRESS: /* Address EA */
2627 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2628 if (gsm_read_ea(&gsm->address, c))
2629 gsm->state = GSM_CONTROL;
2630 break;
2631 case GSM_CONTROL: /* Control Byte */
2632 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2633 gsm->control = c;
2634 gsm->state = GSM_LEN0;
2635 break;
2636 case GSM_LEN0: /* Length EA */
2637 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2638 if (gsm_read_ea(&gsm->len, c)) {
2639 if (gsm->len > gsm->mru) {
2640 gsm->bad_size++;
2641 gsm->state = GSM_SEARCH;
2642 break;
2643 }
2644 gsm->count = 0;
2645 if (!gsm->len)
2646 gsm->state = GSM_FCS;
2647 else
2648 gsm->state = GSM_DATA;
2649 break;
2650 }
2651 gsm->state = GSM_LEN1;
2652 break;
2653 case GSM_LEN1:
2654 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2655 len = c;
2656 gsm->len |= len << 7;
2657 if (gsm->len > gsm->mru) {
2658 gsm->bad_size++;
2659 gsm->state = GSM_SEARCH;
2660 break;
2661 }
2662 gsm->count = 0;
2663 if (!gsm->len)
2664 gsm->state = GSM_FCS;
2665 else
2666 gsm->state = GSM_DATA;
2667 break;
2668 case GSM_DATA: /* Data */
2669 gsm->buf[gsm->count++] = c;
2670 if (gsm->count == gsm->len) {
2671 /* Calculate final FCS for UI frames over all data */
2672 if ((gsm->control & ~PF) != UIH) {
2673 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
2674 gsm->count);
2675 }
2676 gsm->state = GSM_FCS;
2677 }
2678 break;
2679 case GSM_FCS: /* FCS follows the packet */
2680 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2681 gsm->state = GSM_SSOF;
2682 break;
2683 case GSM_SSOF:
2684 gsm->state = GSM_SEARCH;
2685 if (c == GSM0_SOF)
2686 gsm_queue(gsm);
2687 else
2688 gsm->bad_size++;
2689 break;
2690 default:
2691 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
2692 break;
2693 }
2694}
2695
2696/**
2697 * gsm1_receive - perform processing for non-transparency
2698 * @gsm: gsm data for this ldisc instance
2699 * @c: character
2700 *
2701 * Receive bytes in mode 1 (Advanced option)
2702 */
2703
2704static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
2705{
2706 /* handle XON/XOFF */
2707 if ((c & ISO_IEC_646_MASK) == XON) {
2708 gsm->constipated = true;
2709 return;
2710 } else if ((c & ISO_IEC_646_MASK) == XOFF) {
2711 gsm->constipated = false;
2712 /* Kick the link in case it is idling */
2713 gsmld_write_trigger(gsm);
2714 return;
2715 }
2716 if (c == GSM1_SOF) {
2717 /* EOF is only valid in frame if we have got to the data state */
2718 if (gsm->state == GSM_DATA) {
2719 if (gsm->count < 1) {
2720 /* Missing FSC */
2721 gsm->malformed++;
2722 gsm->state = GSM_START;
2723 return;
2724 }
2725 /* Remove the FCS from data */
2726 gsm->count--;
2727 if ((gsm->control & ~PF) != UIH) {
2728 /* Calculate final FCS for UI frames over all
2729 * data but FCS
2730 */
2731 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
2732 gsm->count);
2733 }
2734 /* Add the FCS itself to test against GOOD_FCS */
2735 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
2736 gsm->len = gsm->count;
2737 gsm_queue(gsm);
2738 gsm->state = GSM_START;
2739 return;
2740 }
2741 /* Any partial frame was a runt so go back to start */
2742 if (gsm->state != GSM_START) {
2743 if (gsm->state != GSM_SEARCH)
2744 gsm->malformed++;
2745 gsm->state = GSM_START;
2746 }
2747 /* A SOF in GSM_START means we are still reading idling or
2748 framing bytes */
2749 return;
2750 }
2751
2752 if (c == GSM1_ESCAPE) {
2753 gsm->escape = true;
2754 return;
2755 }
2756
2757 /* Only an unescaped SOF gets us out of GSM search */
2758 if (gsm->state == GSM_SEARCH)
2759 return;
2760
2761 if (gsm->escape) {
2762 c ^= GSM1_ESCAPE_BITS;
2763 gsm->escape = false;
2764 }
2765 switch (gsm->state) {
2766 case GSM_START: /* First byte after SOF */
2767 gsm->address = 0;
2768 gsm->state = GSM_ADDRESS;
2769 gsm->fcs = INIT_FCS;
2770 fallthrough;
2771 case GSM_ADDRESS: /* Address continuation */
2772 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2773 if (gsm_read_ea(&gsm->address, c))
2774 gsm->state = GSM_CONTROL;
2775 break;
2776 case GSM_CONTROL: /* Control Byte */
2777 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
2778 gsm->control = c;
2779 gsm->count = 0;
2780 gsm->state = GSM_DATA;
2781 break;
2782 case GSM_DATA: /* Data */
2783 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
2784 gsm->state = GSM_OVERRUN;
2785 gsm->bad_size++;
2786 } else
2787 gsm->buf[gsm->count++] = c;
2788 break;
2789 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
2790 break;
2791 default:
2792 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
2793 break;
2794 }
2795}
2796
2797/**
2798 * gsm_error - handle tty error
2799 * @gsm: ldisc data
2800 *
2801 * Handle an error in the receipt of data for a frame. Currently we just
2802 * go back to hunting for a SOF.
2803 *
2804 * FIXME: better diagnostics ?
2805 */
2806
2807static void gsm_error(struct gsm_mux *gsm)
2808{
2809 gsm->state = GSM_SEARCH;
2810 gsm->io_error++;
2811}
2812
2813/**
2814 * gsm_cleanup_mux - generic GSM protocol cleanup
2815 * @gsm: our mux
2816 * @disc: disconnect link?
2817 *
2818 * Clean up the bits of the mux which are the same for all framing
2819 * protocols. Remove the mux from the mux table, stop all the timers
2820 * and then shut down each device hanging up the channels as we go.
2821 */
2822
2823static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc)
2824{
2825 int i;
2826 struct gsm_dlci *dlci = gsm->dlci[0];
2827 struct gsm_msg *txq, *ntxq;
2828
2829 gsm->dead = true;
2830 mutex_lock(&gsm->mutex);
2831
2832 if (dlci) {
2833 if (disc && dlci->state != DLCI_CLOSED) {
2834 gsm_dlci_begin_close(dlci);
2835 wait_event(gsm->event, dlci->state == DLCI_CLOSED);
2836 }
2837 dlci->dead = true;
2838 }
2839
2840 /* Finish outstanding timers, making sure they are done */
2841 del_timer_sync(&gsm->kick_timer);
2842 del_timer_sync(&gsm->t2_timer);
2843
2844 /* Finish writing to ldisc */
2845 flush_work(&gsm->tx_work);
2846
2847 /* Free up any link layer users and finally the control channel */
2848 if (gsm->has_devices) {
2849 gsm_unregister_devices(gsm_tty_driver, gsm->num);
2850 gsm->has_devices = false;
2851 }
2852 for (i = NUM_DLCI - 1; i >= 0; i--)
2853 if (gsm->dlci[i])
2854 gsm_dlci_release(gsm->dlci[i]);
2855 mutex_unlock(&gsm->mutex);
2856 /* Now wipe the queues */
2857 tty_ldisc_flush(gsm->tty);
2858 list_for_each_entry_safe(txq, ntxq, &gsm->tx_ctrl_list, list)
2859 kfree(txq);
2860 INIT_LIST_HEAD(&gsm->tx_ctrl_list);
2861 list_for_each_entry_safe(txq, ntxq, &gsm->tx_data_list, list)
2862 kfree(txq);
2863 INIT_LIST_HEAD(&gsm->tx_data_list);
2864}
2865
2866/**
2867 * gsm_activate_mux - generic GSM setup
2868 * @gsm: our mux
2869 *
2870 * Set up the bits of the mux which are the same for all framing
2871 * protocols. Add the mux to the mux table so it can be opened and
2872 * finally kick off connecting to DLCI 0 on the modem.
2873 */
2874
2875static int gsm_activate_mux(struct gsm_mux *gsm)
2876{
2877 struct gsm_dlci *dlci;
2878 int ret;
2879
2880 dlci = gsm_dlci_alloc(gsm, 0);
2881 if (dlci == NULL)
2882 return -ENOMEM;
2883
2884 if (gsm->encoding == GSM_BASIC_OPT)
2885 gsm->receive = gsm0_receive;
2886 else
2887 gsm->receive = gsm1_receive;
2888
2889 ret = gsm_register_devices(gsm_tty_driver, gsm->num);
2890 if (ret)
2891 return ret;
2892
2893 gsm->has_devices = true;
2894 gsm->dead = false; /* Tty opens are now permissible */
2895 return 0;
2896}
2897
2898/**
2899 * gsm_free_mux - free up a mux
2900 * @gsm: mux to free
2901 *
2902 * Dispose of allocated resources for a dead mux
2903 */
2904static void gsm_free_mux(struct gsm_mux *gsm)
2905{
2906 int i;
2907
2908 for (i = 0; i < MAX_MUX; i++) {
2909 if (gsm == gsm_mux[i]) {
2910 gsm_mux[i] = NULL;
2911 break;
2912 }
2913 }
2914 mutex_destroy(&gsm->mutex);
2915 kfree(gsm->txframe);
2916 kfree(gsm->buf);
2917 kfree(gsm);
2918}
2919
2920/**
2921 * gsm_free_muxr - free up a mux
2922 * @ref: kreference to the mux to free
2923 *
2924 * Dispose of allocated resources for a dead mux
2925 */
2926static void gsm_free_muxr(struct kref *ref)
2927{
2928 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2929 gsm_free_mux(gsm);
2930}
2931
2932static inline void mux_get(struct gsm_mux *gsm)
2933{
2934 unsigned long flags;
2935
2936 spin_lock_irqsave(&gsm_mux_lock, flags);
2937 kref_get(&gsm->ref);
2938 spin_unlock_irqrestore(&gsm_mux_lock, flags);
2939}
2940
2941static inline void mux_put(struct gsm_mux *gsm)
2942{
2943 unsigned long flags;
2944
2945 spin_lock_irqsave(&gsm_mux_lock, flags);
2946 kref_put(&gsm->ref, gsm_free_muxr);
2947 spin_unlock_irqrestore(&gsm_mux_lock, flags);
2948}
2949
2950static inline unsigned int mux_num_to_base(struct gsm_mux *gsm)
2951{
2952 return gsm->num * NUM_DLCI;
2953}
2954
2955static inline unsigned int mux_line_to_num(unsigned int line)
2956{
2957 return line / NUM_DLCI;
2958}
2959
2960/**
2961 * gsm_alloc_mux - allocate a mux
2962 *
2963 * Creates a new mux ready for activation.
2964 */
2965
2966static struct gsm_mux *gsm_alloc_mux(void)
2967{
2968 int i;
2969 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2970 if (gsm == NULL)
2971 return NULL;
2972 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2973 if (gsm->buf == NULL) {
2974 kfree(gsm);
2975 return NULL;
2976 }
2977 gsm->txframe = kmalloc(2 * (MAX_MTU + PROT_OVERHEAD - 1), GFP_KERNEL);
2978 if (gsm->txframe == NULL) {
2979 kfree(gsm->buf);
2980 kfree(gsm);
2981 return NULL;
2982 }
2983 spin_lock_init(&gsm->lock);
2984 mutex_init(&gsm->mutex);
2985 kref_init(&gsm->ref);
2986 INIT_LIST_HEAD(&gsm->tx_ctrl_list);
2987 INIT_LIST_HEAD(&gsm->tx_data_list);
2988 timer_setup(&gsm->kick_timer, gsm_kick_timer, 0);
2989 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
2990 INIT_WORK(&gsm->tx_work, gsmld_write_task);
2991 init_waitqueue_head(&gsm->event);
2992 spin_lock_init(&gsm->control_lock);
2993 spin_lock_init(&gsm->tx_lock);
2994
2995 gsm->t1 = T1;
2996 gsm->t2 = T2;
2997 gsm->t3 = T3;
2998 gsm->n2 = N2;
2999 gsm->k = K;
3000 gsm->ftype = UIH;
3001 gsm->adaption = 1;
3002 gsm->encoding = GSM_ADV_OPT;
3003 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
3004 gsm->mtu = 64;
3005 gsm->dead = true; /* Avoid early tty opens */
3006
3007 /* Store the instance to the mux array or abort if no space is
3008 * available.
3009 */
3010 spin_lock(&gsm_mux_lock);
3011 for (i = 0; i < MAX_MUX; i++) {
3012 if (!gsm_mux[i]) {
3013 gsm_mux[i] = gsm;
3014 gsm->num = i;
3015 break;
3016 }
3017 }
3018 spin_unlock(&gsm_mux_lock);
3019 if (i == MAX_MUX) {
3020 mutex_destroy(&gsm->mutex);
3021 kfree(gsm->txframe);
3022 kfree(gsm->buf);
3023 kfree(gsm);
3024 return NULL;
3025 }
3026
3027 return gsm;
3028}
3029
3030static void gsm_copy_config_values(struct gsm_mux *gsm,
3031 struct gsm_config *c)
3032{
3033 memset(c, 0, sizeof(*c));
3034 c->adaption = gsm->adaption;
3035 c->encapsulation = gsm->encoding;
3036 c->initiator = gsm->initiator;
3037 c->t1 = gsm->t1;
3038 c->t2 = gsm->t2;
3039 c->t3 = gsm->t3;
3040 c->n2 = gsm->n2;
3041 if (gsm->ftype == UIH)
3042 c->i = 1;
3043 else
3044 c->i = 2;
3045 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i);
3046 c->mru = gsm->mru;
3047 c->mtu = gsm->mtu;
3048 c->k = gsm->k;
3049}
3050
3051static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
3052{
3053 int ret = 0;
3054 int need_close = 0;
3055 int need_restart = 0;
3056
3057 /* Stuff we don't support yet - UI or I frame transport, windowing */
3058 if ((c->adaption != 1 && c->adaption != 2) || c->k)
3059 return -EOPNOTSUPP;
3060 /* Check the MRU/MTU range looks sane */
3061 if (c->mru < MIN_MTU || c->mtu < MIN_MTU)
3062 return -EINVAL;
3063 if (c->mru > MAX_MRU || c->mtu > MAX_MTU)
3064 return -EINVAL;
3065 if (c->t3 > MAX_T3)
3066 return -EINVAL;
3067 if (c->n2 > 255)
3068 return -EINVAL;
3069 if (c->encapsulation > 1) /* Basic, advanced, no I */
3070 return -EINVAL;
3071 if (c->initiator > 1)
3072 return -EINVAL;
3073 if (c->k > MAX_WINDOW_SIZE)
3074 return -EINVAL;
3075 if (c->i == 0 || c->i > 2) /* UIH and UI only */
3076 return -EINVAL;
3077 /*
3078 * See what is needed for reconfiguration
3079 */
3080
3081 /* Timing fields */
3082 if (c->t1 != 0 && c->t1 != gsm->t1)
3083 need_restart = 1;
3084 if (c->t2 != 0 && c->t2 != gsm->t2)
3085 need_restart = 1;
3086 if (c->encapsulation != gsm->encoding)
3087 need_restart = 1;
3088 if (c->adaption != gsm->adaption)
3089 need_restart = 1;
3090 /* Requires care */
3091 if (c->initiator != gsm->initiator)
3092 need_close = 1;
3093 if (c->mru != gsm->mru)
3094 need_restart = 1;
3095 if (c->mtu != gsm->mtu)
3096 need_restart = 1;
3097
3098 /*
3099 * Close down what is needed, restart and initiate the new
3100 * configuration. On the first time there is no DLCI[0]
3101 * and closing or cleaning up is not necessary.
3102 */
3103 if (need_close || need_restart)
3104 gsm_cleanup_mux(gsm, true);
3105
3106 gsm->initiator = c->initiator;
3107 gsm->mru = c->mru;
3108 gsm->mtu = c->mtu;
3109 gsm->encoding = c->encapsulation ? GSM_ADV_OPT : GSM_BASIC_OPT;
3110 gsm->adaption = c->adaption;
3111 gsm->n2 = c->n2;
3112
3113 if (c->i == 1)
3114 gsm->ftype = UIH;
3115 else if (c->i == 2)
3116 gsm->ftype = UI;
3117
3118 if (c->t1)
3119 gsm->t1 = c->t1;
3120 if (c->t2)
3121 gsm->t2 = c->t2;
3122 if (c->t3)
3123 gsm->t3 = c->t3;
3124 if (c->k)
3125 gsm->k = c->k;
3126
3127 /*
3128 * FIXME: We need to separate activation/deactivation from adding
3129 * and removing from the mux array
3130 */
3131 if (gsm->dead) {
3132 ret = gsm_activate_mux(gsm);
3133 if (ret)
3134 return ret;
3135 if (gsm->initiator)
3136 gsm_dlci_begin_open(gsm->dlci[0]);
3137 }
3138 return 0;
3139}
3140
3141/**
3142 * gsmld_output - write to link
3143 * @gsm: our mux
3144 * @data: bytes to output
3145 * @len: size
3146 *
3147 * Write a block of data from the GSM mux to the data channel. This
3148 * will eventually be serialized from above but at the moment isn't.
3149 */
3150
3151static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
3152{
3153 if (tty_write_room(gsm->tty) < len) {
3154 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
3155 return -ENOSPC;
3156 }
3157 if (debug & DBG_DATA)
3158 gsm_hex_dump_bytes(__func__, data, len);
3159 return gsm->tty->ops->write(gsm->tty, data, len);
3160}
3161
3162
3163/**
3164 * gsmld_write_trigger - schedule ldisc write task
3165 * @gsm: our mux
3166 */
3167static void gsmld_write_trigger(struct gsm_mux *gsm)
3168{
3169 if (!gsm || !gsm->dlci[0] || gsm->dlci[0]->dead)
3170 return;
3171 schedule_work(&gsm->tx_work);
3172}
3173
3174
3175/**
3176 * gsmld_write_task - ldisc write task
3177 * @work: our tx write work
3178 *
3179 * Writes out data to the ldisc if possible. We are doing this here to
3180 * avoid dead-locking. This returns if no space or data is left for output.
3181 */
3182static void gsmld_write_task(struct work_struct *work)
3183{
3184 struct gsm_mux *gsm = container_of(work, struct gsm_mux, tx_work);
3185 unsigned long flags;
3186 int i, ret;
3187
3188 /* All outstanding control channel and control messages and one data
3189 * frame is sent.
3190 */
3191 ret = -ENODEV;
3192 spin_lock_irqsave(&gsm->tx_lock, flags);
3193 if (gsm->tty)
3194 ret = gsm_data_kick(gsm);
3195 spin_unlock_irqrestore(&gsm->tx_lock, flags);
3196
3197 if (ret >= 0)
3198 for (i = 0; i < NUM_DLCI; i++)
3199 if (gsm->dlci[i])
3200 tty_port_tty_wakeup(&gsm->dlci[i]->port);
3201}
3202
3203/**
3204 * gsmld_attach_gsm - mode set up
3205 * @tty: our tty structure
3206 * @gsm: our mux
3207 *
3208 * Set up the MUX for basic mode and commence connecting to the
3209 * modem. Currently called from the line discipline set up but
3210 * will need moving to an ioctl path.
3211 */
3212
3213static void gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
3214{
3215 gsm->tty = tty_kref_get(tty);
3216 /* Turn off tty XON/XOFF handling to handle it explicitly. */
3217 gsm->old_c_iflag = tty->termios.c_iflag;
3218 tty->termios.c_iflag &= (IXON | IXOFF);
3219}
3220
3221/**
3222 * gsmld_detach_gsm - stop doing 0710 mux
3223 * @tty: tty attached to the mux
3224 * @gsm: mux
3225 *
3226 * Shutdown and then clean up the resources used by the line discipline
3227 */
3228
3229static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
3230{
3231 WARN_ON(tty != gsm->tty);
3232 /* Restore tty XON/XOFF handling. */
3233 gsm->tty->termios.c_iflag = gsm->old_c_iflag;
3234 tty_kref_put(gsm->tty);
3235 gsm->tty = NULL;
3236}
3237
3238static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
3239 const char *fp, int count)
3240{
3241 struct gsm_mux *gsm = tty->disc_data;
3242 char flags = TTY_NORMAL;
3243
3244 if (debug & DBG_DATA)
3245 gsm_hex_dump_bytes(__func__, cp, count);
3246
3247 for (; count; count--, cp++) {
3248 if (fp)
3249 flags = *fp++;
3250 switch (flags) {
3251 case TTY_NORMAL:
3252 if (gsm->receive)
3253 gsm->receive(gsm, *cp);
3254 break;
3255 case TTY_OVERRUN:
3256 case TTY_BREAK:
3257 case TTY_PARITY:
3258 case TTY_FRAME:
3259 gsm_error(gsm);
3260 break;
3261 default:
3262 WARN_ONCE(1, "%s: unknown flag %d\n",
3263 tty_name(tty), flags);
3264 break;
3265 }
3266 }
3267 /* FASYNC if needed ? */
3268 /* If clogged call tty_throttle(tty); */
3269}
3270
3271/**
3272 * gsmld_flush_buffer - clean input queue
3273 * @tty: terminal device
3274 *
3275 * Flush the input buffer. Called when the line discipline is
3276 * being closed, when the tty layer wants the buffer flushed (eg
3277 * at hangup).
3278 */
3279
3280static void gsmld_flush_buffer(struct tty_struct *tty)
3281{
3282}
3283
3284/**
3285 * gsmld_close - close the ldisc for this tty
3286 * @tty: device
3287 *
3288 * Called from the terminal layer when this line discipline is
3289 * being shut down, either because of a close or becsuse of a
3290 * discipline change. The function will not be called while other
3291 * ldisc methods are in progress.
3292 */
3293
3294static void gsmld_close(struct tty_struct *tty)
3295{
3296 struct gsm_mux *gsm = tty->disc_data;
3297
3298 /* The ldisc locks and closes the port before calling our close. This
3299 * means we have no way to do a proper disconnect. We will not bother
3300 * to do one.
3301 */
3302 gsm_cleanup_mux(gsm, false);
3303
3304 gsmld_detach_gsm(tty, gsm);
3305
3306 gsmld_flush_buffer(tty);
3307 /* Do other clean up here */
3308 mux_put(gsm);
3309}
3310
3311/**
3312 * gsmld_open - open an ldisc
3313 * @tty: terminal to open
3314 *
3315 * Called when this line discipline is being attached to the
3316 * terminal device. Can sleep. Called serialized so that no
3317 * other events will occur in parallel. No further open will occur
3318 * until a close.
3319 */
3320
3321static int gsmld_open(struct tty_struct *tty)
3322{
3323 struct gsm_mux *gsm;
3324
3325 if (tty->ops->write == NULL)
3326 return -EINVAL;
3327
3328 /* Attach our ldisc data */
3329 gsm = gsm_alloc_mux();
3330 if (gsm == NULL)
3331 return -ENOMEM;
3332
3333 tty->disc_data = gsm;
3334 tty->receive_room = 65536;
3335
3336 /* Attach the initial passive connection */
3337 gsm->encoding = GSM_ADV_OPT;
3338 gsmld_attach_gsm(tty, gsm);
3339
3340 return 0;
3341}
3342
3343/**
3344 * gsmld_write_wakeup - asynchronous I/O notifier
3345 * @tty: tty device
3346 *
3347 * Required for the ptys, serial driver etc. since processes
3348 * that attach themselves to the master and rely on ASYNC
3349 * IO must be woken up
3350 */
3351
3352static void gsmld_write_wakeup(struct tty_struct *tty)
3353{
3354 struct gsm_mux *gsm = tty->disc_data;
3355
3356 /* Queue poll */
3357 gsmld_write_trigger(gsm);
3358}
3359
3360/**
3361 * gsmld_read - read function for tty
3362 * @tty: tty device
3363 * @file: file object
3364 * @buf: userspace buffer pointer
3365 * @nr: size of I/O
3366 * @cookie: unused
3367 * @offset: unused
3368 *
3369 * Perform reads for the line discipline. We are guaranteed that the
3370 * line discipline will not be closed under us but we may get multiple
3371 * parallel readers and must handle this ourselves. We may also get
3372 * a hangup. Always called in user context, may sleep.
3373 *
3374 * This code must be sure never to sleep through a hangup.
3375 */
3376
3377static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
3378 unsigned char *buf, size_t nr,
3379 void **cookie, unsigned long offset)
3380{
3381 return -EOPNOTSUPP;
3382}
3383
3384/**
3385 * gsmld_write - write function for tty
3386 * @tty: tty device
3387 * @file: file object
3388 * @buf: userspace buffer pointer
3389 * @nr: size of I/O
3390 *
3391 * Called when the owner of the device wants to send a frame
3392 * itself (or some other control data). The data is transferred
3393 * as-is and must be properly framed and checksummed as appropriate
3394 * by userspace. Frames are either sent whole or not at all as this
3395 * avoids pain user side.
3396 */
3397
3398static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
3399 const unsigned char *buf, size_t nr)
3400{
3401 struct gsm_mux *gsm = tty->disc_data;
3402 unsigned long flags;
3403 int space;
3404 int ret;
3405
3406 if (!gsm)
3407 return -ENODEV;
3408
3409 ret = -ENOBUFS;
3410 spin_lock_irqsave(&gsm->tx_lock, flags);
3411 space = tty_write_room(tty);
3412 if (space >= nr)
3413 ret = tty->ops->write(tty, buf, nr);
3414 else
3415 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
3416 spin_unlock_irqrestore(&gsm->tx_lock, flags);
3417
3418 return ret;
3419}
3420
3421/**
3422 * gsmld_poll - poll method for N_GSM0710
3423 * @tty: terminal device
3424 * @file: file accessing it
3425 * @wait: poll table
3426 *
3427 * Called when the line discipline is asked to poll() for data or
3428 * for special events. This code is not serialized with respect to
3429 * other events save open/close.
3430 *
3431 * This code must be sure never to sleep through a hangup.
3432 * Called without the kernel lock held - fine
3433 */
3434
3435static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
3436 poll_table *wait)
3437{
3438 __poll_t mask = 0;
3439 struct gsm_mux *gsm = tty->disc_data;
3440
3441 poll_wait(file, &tty->read_wait, wait);
3442 poll_wait(file, &tty->write_wait, wait);
3443
3444 if (gsm->dead)
3445 mask |= EPOLLHUP;
3446 if (tty_hung_up_p(file))
3447 mask |= EPOLLHUP;
3448 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
3449 mask |= EPOLLHUP;
3450 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
3451 mask |= EPOLLOUT | EPOLLWRNORM;
3452 return mask;
3453}
3454
3455static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd,
3456 unsigned long arg)
3457{
3458 struct gsm_config c;
3459 struct gsm_mux *gsm = tty->disc_data;
3460 unsigned int base;
3461
3462 switch (cmd) {
3463 case GSMIOC_GETCONF:
3464 gsm_copy_config_values(gsm, &c);
3465 if (copy_to_user((void __user *)arg, &c, sizeof(c)))
3466 return -EFAULT;
3467 return 0;
3468 case GSMIOC_SETCONF:
3469 if (copy_from_user(&c, (void __user *)arg, sizeof(c)))
3470 return -EFAULT;
3471 return gsm_config(gsm, &c);
3472 case GSMIOC_GETFIRST:
3473 base = mux_num_to_base(gsm);
3474 return put_user(base + 1, (__u32 __user *)arg);
3475 default:
3476 return n_tty_ioctl_helper(tty, cmd, arg);
3477 }
3478}
3479
3480/*
3481 * Network interface
3482 *
3483 */
3484
3485static int gsm_mux_net_open(struct net_device *net)
3486{
3487 pr_debug("%s called\n", __func__);
3488 netif_start_queue(net);
3489 return 0;
3490}
3491
3492static int gsm_mux_net_close(struct net_device *net)
3493{
3494 netif_stop_queue(net);
3495 return 0;
3496}
3497
3498static void dlci_net_free(struct gsm_dlci *dlci)
3499{
3500 if (!dlci->net) {
3501 WARN_ON(1);
3502 return;
3503 }
3504 dlci->adaption = dlci->prev_adaption;
3505 dlci->data = dlci->prev_data;
3506 free_netdev(dlci->net);
3507 dlci->net = NULL;
3508}
3509static void net_free(struct kref *ref)
3510{
3511 struct gsm_mux_net *mux_net;
3512 struct gsm_dlci *dlci;
3513
3514 mux_net = container_of(ref, struct gsm_mux_net, ref);
3515 dlci = mux_net->dlci;
3516
3517 if (dlci->net) {
3518 unregister_netdev(dlci->net);
3519 dlci_net_free(dlci);
3520 }
3521}
3522
3523static inline void muxnet_get(struct gsm_mux_net *mux_net)
3524{
3525 kref_get(&mux_net->ref);
3526}
3527
3528static inline void muxnet_put(struct gsm_mux_net *mux_net)
3529{
3530 kref_put(&mux_net->ref, net_free);
3531}
3532
3533static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
3534 struct net_device *net)
3535{
3536 struct gsm_mux_net *mux_net = netdev_priv(net);
3537 struct gsm_dlci *dlci = mux_net->dlci;
3538 muxnet_get(mux_net);
3539
3540 skb_queue_head(&dlci->skb_list, skb);
3541 net->stats.tx_packets++;
3542 net->stats.tx_bytes += skb->len;
3543 gsm_dlci_data_kick(dlci);
3544 /* And tell the kernel when the last transmit started. */
3545 netif_trans_update(net);
3546 muxnet_put(mux_net);
3547 return NETDEV_TX_OK;
3548}
3549
3550/* called when a packet did not ack after watchdogtimeout */
3551static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue)
3552{
3553 /* Tell syslog we are hosed. */
3554 dev_dbg(&net->dev, "Tx timed out.\n");
3555
3556 /* Update statistics */
3557 net->stats.tx_errors++;
3558}
3559
3560static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
3561 const unsigned char *in_buf, int size)
3562{
3563 struct net_device *net = dlci->net;
3564 struct sk_buff *skb;
3565 struct gsm_mux_net *mux_net = netdev_priv(net);
3566 muxnet_get(mux_net);
3567
3568 /* Allocate an sk_buff */
3569 skb = dev_alloc_skb(size + NET_IP_ALIGN);
3570 if (!skb) {
3571 /* We got no receive buffer. */
3572 net->stats.rx_dropped++;
3573 muxnet_put(mux_net);
3574 return;
3575 }
3576 skb_reserve(skb, NET_IP_ALIGN);
3577 skb_put_data(skb, in_buf, size);
3578
3579 skb->dev = net;
3580 skb->protocol = htons(ETH_P_IP);
3581
3582 /* Ship it off to the kernel */
3583 netif_rx(skb);
3584
3585 /* update out statistics */
3586 net->stats.rx_packets++;
3587 net->stats.rx_bytes += size;
3588 muxnet_put(mux_net);
3589 return;
3590}
3591
3592static void gsm_mux_net_init(struct net_device *net)
3593{
3594 static const struct net_device_ops gsm_netdev_ops = {
3595 .ndo_open = gsm_mux_net_open,
3596 .ndo_stop = gsm_mux_net_close,
3597 .ndo_start_xmit = gsm_mux_net_start_xmit,
3598 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
3599 };
3600
3601 net->netdev_ops = &gsm_netdev_ops;
3602
3603 /* fill in the other fields */
3604 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
3605 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
3606 net->type = ARPHRD_NONE;
3607 net->tx_queue_len = 10;
3608}
3609
3610
3611/* caller holds the dlci mutex */
3612static void gsm_destroy_network(struct gsm_dlci *dlci)
3613{
3614 struct gsm_mux_net *mux_net;
3615
3616 pr_debug("destroy network interface\n");
3617 if (!dlci->net)
3618 return;
3619 mux_net = netdev_priv(dlci->net);
3620 muxnet_put(mux_net);
3621}
3622
3623
3624/* caller holds the dlci mutex */
3625static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
3626{
3627 char *netname;
3628 int retval = 0;
3629 struct net_device *net;
3630 struct gsm_mux_net *mux_net;
3631
3632 if (!capable(CAP_NET_ADMIN))
3633 return -EPERM;
3634
3635 /* Already in a non tty mode */
3636 if (dlci->adaption > 2)
3637 return -EBUSY;
3638
3639 if (nc->protocol != htons(ETH_P_IP))
3640 return -EPROTONOSUPPORT;
3641
3642 if (nc->adaption != 3 && nc->adaption != 4)
3643 return -EPROTONOSUPPORT;
3644
3645 pr_debug("create network interface\n");
3646
3647 netname = "gsm%d";
3648 if (nc->if_name[0] != '\0')
3649 netname = nc->if_name;
3650 net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
3651 NET_NAME_UNKNOWN, gsm_mux_net_init);
3652 if (!net) {
3653 pr_err("alloc_netdev failed\n");
3654 return -ENOMEM;
3655 }
3656 net->mtu = dlci->mtu;
3657 net->min_mtu = MIN_MTU;
3658 net->max_mtu = dlci->mtu;
3659 mux_net = netdev_priv(net);
3660 mux_net->dlci = dlci;
3661 kref_init(&mux_net->ref);
3662 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
3663
3664 /* reconfigure dlci for network */
3665 dlci->prev_adaption = dlci->adaption;
3666 dlci->prev_data = dlci->data;
3667 dlci->adaption = nc->adaption;
3668 dlci->data = gsm_mux_rx_netchar;
3669 dlci->net = net;
3670
3671 pr_debug("register netdev\n");
3672 retval = register_netdev(net);
3673 if (retval) {
3674 pr_err("network register fail %d\n", retval);
3675 dlci_net_free(dlci);
3676 return retval;
3677 }
3678 return net->ifindex; /* return network index */
3679}
3680
3681/* Line discipline for real tty */
3682static struct tty_ldisc_ops tty_ldisc_packet = {
3683 .owner = THIS_MODULE,
3684 .num = N_GSM0710,
3685 .name = "n_gsm",
3686 .open = gsmld_open,
3687 .close = gsmld_close,
3688 .flush_buffer = gsmld_flush_buffer,
3689 .read = gsmld_read,
3690 .write = gsmld_write,
3691 .ioctl = gsmld_ioctl,
3692 .poll = gsmld_poll,
3693 .receive_buf = gsmld_receive_buf,
3694 .write_wakeup = gsmld_write_wakeup
3695};
3696
3697/*
3698 * Virtual tty side
3699 */
3700
3701/**
3702 * gsm_modem_upd_via_data - send modem bits via convergence layer
3703 * @dlci: channel
3704 * @brk: break signal
3705 *
3706 * Send an empty frame to signal mobile state changes and to transmit the
3707 * break signal for adaption 2.
3708 */
3709
3710static void gsm_modem_upd_via_data(struct gsm_dlci *dlci, u8 brk)
3711{
3712 struct gsm_mux *gsm = dlci->gsm;
3713 unsigned long flags;
3714
3715 if (dlci->state != DLCI_OPEN || dlci->adaption != 2)
3716 return;
3717
3718 spin_lock_irqsave(&gsm->tx_lock, flags);
3719 gsm_dlci_modem_output(gsm, dlci, brk);
3720 spin_unlock_irqrestore(&gsm->tx_lock, flags);
3721}
3722
3723/**
3724 * gsm_modem_upd_via_msc - send modem bits via control frame
3725 * @dlci: channel
3726 * @brk: break signal
3727 */
3728
3729static int gsm_modem_upd_via_msc(struct gsm_dlci *dlci, u8 brk)
3730{
3731 u8 modembits[3];
3732 struct gsm_control *ctrl;
3733 int len = 2;
3734
3735 if (dlci->gsm->encoding != GSM_BASIC_OPT)
3736 return 0;
3737
3738 modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */
3739 if (!brk) {
3740 modembits[1] = (gsm_encode_modem(dlci) << 1) | EA;
3741 } else {
3742 modembits[1] = gsm_encode_modem(dlci) << 1;
3743 modembits[2] = (brk << 4) | 2 | EA; /* Length, Break, EA */
3744 len++;
3745 }
3746 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len);
3747 if (ctrl == NULL)
3748 return -ENOMEM;
3749 return gsm_control_wait(dlci->gsm, ctrl);
3750}
3751
3752/**
3753 * gsm_modem_update - send modem status line state
3754 * @dlci: channel
3755 * @brk: break signal
3756 */
3757
3758static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk)
3759{
3760 if (dlci->adaption == 2) {
3761 /* Send convergence layer type 2 empty data frame. */
3762 gsm_modem_upd_via_data(dlci, brk);
3763 return 0;
3764 } else if (dlci->gsm->encoding == GSM_BASIC_OPT) {
3765 /* Send as MSC control message. */
3766 return gsm_modem_upd_via_msc(dlci, brk);
3767 }
3768
3769 /* Modem status lines are not supported. */
3770 return -EPROTONOSUPPORT;
3771}
3772
3773static int gsm_carrier_raised(struct tty_port *port)
3774{
3775 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
3776 struct gsm_mux *gsm = dlci->gsm;
3777
3778 /* Not yet open so no carrier info */
3779 if (dlci->state != DLCI_OPEN)
3780 return 0;
3781 if (debug & DBG_CD_ON)
3782 return 1;
3783
3784 /*
3785 * Basic mode with control channel in ADM mode may not respond
3786 * to CMD_MSC at all and modem_rx is empty.
3787 */
3788 if (gsm->encoding == GSM_BASIC_OPT &&
3789 gsm->dlci[0]->mode == DLCI_MODE_ADM && !dlci->modem_rx)
3790 return 1;
3791
3792 return dlci->modem_rx & TIOCM_CD;
3793}
3794
3795static void gsm_dtr_rts(struct tty_port *port, int onoff)
3796{
3797 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
3798 unsigned int modem_tx = dlci->modem_tx;
3799 if (onoff)
3800 modem_tx |= TIOCM_DTR | TIOCM_RTS;
3801 else
3802 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
3803 if (modem_tx != dlci->modem_tx) {
3804 dlci->modem_tx = modem_tx;
3805 gsm_modem_update(dlci, 0);
3806 }
3807}
3808
3809static const struct tty_port_operations gsm_port_ops = {
3810 .carrier_raised = gsm_carrier_raised,
3811 .dtr_rts = gsm_dtr_rts,
3812 .destruct = gsm_dlci_free,
3813};
3814
3815static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
3816{
3817 struct gsm_mux *gsm;
3818 struct gsm_dlci *dlci;
3819 unsigned int line = tty->index;
3820 unsigned int mux = mux_line_to_num(line);
3821 bool alloc = false;
3822 int ret;
3823
3824 line = line & 0x3F;
3825
3826 if (mux >= MAX_MUX)
3827 return -ENXIO;
3828 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
3829 if (gsm_mux[mux] == NULL)
3830 return -EUNATCH;
3831 if (line == 0 || line > 61) /* 62/63 reserved */
3832 return -ECHRNG;
3833 gsm = gsm_mux[mux];
3834 if (gsm->dead)
3835 return -EL2HLT;
3836 /* If DLCI 0 is not yet fully open return an error.
3837 This is ok from a locking
3838 perspective as we don't have to worry about this
3839 if DLCI0 is lost */
3840 mutex_lock(&gsm->mutex);
3841 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
3842 mutex_unlock(&gsm->mutex);
3843 return -EL2NSYNC;
3844 }
3845 dlci = gsm->dlci[line];
3846 if (dlci == NULL) {
3847 alloc = true;
3848 dlci = gsm_dlci_alloc(gsm, line);
3849 }
3850 if (dlci == NULL) {
3851 mutex_unlock(&gsm->mutex);
3852 return -ENOMEM;
3853 }
3854 ret = tty_port_install(&dlci->port, driver, tty);
3855 if (ret) {
3856 if (alloc)
3857 dlci_put(dlci);
3858 mutex_unlock(&gsm->mutex);
3859 return ret;
3860 }
3861
3862 dlci_get(dlci);
3863 dlci_get(gsm->dlci[0]);
3864 mux_get(gsm);
3865 tty->driver_data = dlci;
3866 mutex_unlock(&gsm->mutex);
3867
3868 return 0;
3869}
3870
3871static int gsmtty_open(struct tty_struct *tty, struct file *filp)
3872{
3873 struct gsm_dlci *dlci = tty->driver_data;
3874 struct tty_port *port = &dlci->port;
3875 struct gsm_mux *gsm = dlci->gsm;
3876
3877 port->count++;
3878 tty_port_tty_set(port, tty);
3879
3880 dlci->modem_rx = 0;
3881 /* We could in theory open and close before we wait - eg if we get
3882 a DM straight back. This is ok as that will have caused a hangup */
3883 tty_port_set_initialized(port, 1);
3884 /* Start sending off SABM messages */
3885 if (gsm->initiator)
3886 gsm_dlci_begin_open(dlci);
3887 else
3888 gsm_dlci_set_opening(dlci);
3889 /* And wait for virtual carrier */
3890 return tty_port_block_til_ready(port, tty, filp);
3891}
3892
3893static void gsmtty_close(struct tty_struct *tty, struct file *filp)
3894{
3895 struct gsm_dlci *dlci = tty->driver_data;
3896
3897 if (dlci == NULL)
3898 return;
3899 if (dlci->state == DLCI_CLOSED)
3900 return;
3901 mutex_lock(&dlci->mutex);
3902 gsm_destroy_network(dlci);
3903 mutex_unlock(&dlci->mutex);
3904 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
3905 return;
3906 gsm_dlci_begin_close(dlci);
3907 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
3908 tty_port_lower_dtr_rts(&dlci->port);
3909 tty_port_close_end(&dlci->port, tty);
3910 tty_port_tty_set(&dlci->port, NULL);
3911 return;
3912}
3913
3914static void gsmtty_hangup(struct tty_struct *tty)
3915{
3916 struct gsm_dlci *dlci = tty->driver_data;
3917 if (dlci->state == DLCI_CLOSED)
3918 return;
3919 tty_port_hangup(&dlci->port);
3920 gsm_dlci_begin_close(dlci);
3921}
3922
3923static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
3924 int len)
3925{
3926 int sent;
3927 struct gsm_dlci *dlci = tty->driver_data;
3928 if (dlci->state == DLCI_CLOSED)
3929 return -EINVAL;
3930 /* Stuff the bytes into the fifo queue */
3931 sent = kfifo_in_locked(&dlci->fifo, buf, len, &dlci->lock);
3932 /* Need to kick the channel */
3933 gsm_dlci_data_kick(dlci);
3934 return sent;
3935}
3936
3937static unsigned int gsmtty_write_room(struct tty_struct *tty)
3938{
3939 struct gsm_dlci *dlci = tty->driver_data;
3940 if (dlci->state == DLCI_CLOSED)
3941 return 0;
3942 return kfifo_avail(&dlci->fifo);
3943}
3944
3945static unsigned int gsmtty_chars_in_buffer(struct tty_struct *tty)
3946{
3947 struct gsm_dlci *dlci = tty->driver_data;
3948 if (dlci->state == DLCI_CLOSED)
3949 return 0;
3950 return kfifo_len(&dlci->fifo);
3951}
3952
3953static void gsmtty_flush_buffer(struct tty_struct *tty)
3954{
3955 struct gsm_dlci *dlci = tty->driver_data;
3956 unsigned long flags;
3957
3958 if (dlci->state == DLCI_CLOSED)
3959 return;
3960 /* Caution needed: If we implement reliable transport classes
3961 then the data being transmitted can't simply be junked once
3962 it has first hit the stack. Until then we can just blow it
3963 away */
3964 spin_lock_irqsave(&dlci->lock, flags);
3965 kfifo_reset(&dlci->fifo);
3966 spin_unlock_irqrestore(&dlci->lock, flags);
3967 /* Need to unhook this DLCI from the transmit queue logic */
3968}
3969
3970static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
3971{
3972 /* The FIFO handles the queue so the kernel will do the right
3973 thing waiting on chars_in_buffer before calling us. No work
3974 to do here */
3975}
3976
3977static int gsmtty_tiocmget(struct tty_struct *tty)
3978{
3979 struct gsm_dlci *dlci = tty->driver_data;
3980 if (dlci->state == DLCI_CLOSED)
3981 return -EINVAL;
3982 return dlci->modem_rx;
3983}
3984
3985static int gsmtty_tiocmset(struct tty_struct *tty,
3986 unsigned int set, unsigned int clear)
3987{
3988 struct gsm_dlci *dlci = tty->driver_data;
3989 unsigned int modem_tx = dlci->modem_tx;
3990
3991 if (dlci->state == DLCI_CLOSED)
3992 return -EINVAL;
3993 modem_tx &= ~clear;
3994 modem_tx |= set;
3995
3996 if (modem_tx != dlci->modem_tx) {
3997 dlci->modem_tx = modem_tx;
3998 return gsm_modem_update(dlci, 0);
3999 }
4000 return 0;
4001}
4002
4003
4004static int gsmtty_ioctl(struct tty_struct *tty,
4005 unsigned int cmd, unsigned long arg)
4006{
4007 struct gsm_dlci *dlci = tty->driver_data;
4008 struct gsm_netconfig nc;
4009 int index;
4010
4011 if (dlci->state == DLCI_CLOSED)
4012 return -EINVAL;
4013 switch (cmd) {
4014 case GSMIOC_ENABLE_NET:
4015 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
4016 return -EFAULT;
4017 nc.if_name[IFNAMSIZ-1] = '\0';
4018 /* return net interface index or error code */
4019 mutex_lock(&dlci->mutex);
4020 index = gsm_create_network(dlci, &nc);
4021 mutex_unlock(&dlci->mutex);
4022 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
4023 return -EFAULT;
4024 return index;
4025 case GSMIOC_DISABLE_NET:
4026 if (!capable(CAP_NET_ADMIN))
4027 return -EPERM;
4028 mutex_lock(&dlci->mutex);
4029 gsm_destroy_network(dlci);
4030 mutex_unlock(&dlci->mutex);
4031 return 0;
4032 default:
4033 return -ENOIOCTLCMD;
4034 }
4035}
4036
4037static void gsmtty_set_termios(struct tty_struct *tty,
4038 const struct ktermios *old)
4039{
4040 struct gsm_dlci *dlci = tty->driver_data;
4041 if (dlci->state == DLCI_CLOSED)
4042 return;
4043 /* For the moment its fixed. In actual fact the speed information
4044 for the virtual channel can be propogated in both directions by
4045 the RPN control message. This however rapidly gets nasty as we
4046 then have to remap modem signals each way according to whether
4047 our virtual cable is null modem etc .. */
4048 tty_termios_copy_hw(&tty->termios, old);
4049}
4050
4051static void gsmtty_throttle(struct tty_struct *tty)
4052{
4053 struct gsm_dlci *dlci = tty->driver_data;
4054 if (dlci->state == DLCI_CLOSED)
4055 return;
4056 if (C_CRTSCTS(tty))
4057 dlci->modem_tx &= ~TIOCM_RTS;
4058 dlci->throttled = true;
4059 /* Send an MSC with RTS cleared */
4060 gsm_modem_update(dlci, 0);
4061}
4062
4063static void gsmtty_unthrottle(struct tty_struct *tty)
4064{
4065 struct gsm_dlci *dlci = tty->driver_data;
4066 if (dlci->state == DLCI_CLOSED)
4067 return;
4068 if (C_CRTSCTS(tty))
4069 dlci->modem_tx |= TIOCM_RTS;
4070 dlci->throttled = false;
4071 /* Send an MSC with RTS set */
4072 gsm_modem_update(dlci, 0);
4073}
4074
4075static int gsmtty_break_ctl(struct tty_struct *tty, int state)
4076{
4077 struct gsm_dlci *dlci = tty->driver_data;
4078 int encode = 0; /* Off */
4079 if (dlci->state == DLCI_CLOSED)
4080 return -EINVAL;
4081
4082 if (state == -1) /* "On indefinitely" - we can't encode this
4083 properly */
4084 encode = 0x0F;
4085 else if (state > 0) {
4086 encode = state / 200; /* mS to encoding */
4087 if (encode > 0x0F)
4088 encode = 0x0F; /* Best effort */
4089 }
4090 return gsm_modem_update(dlci, encode);
4091}
4092
4093static void gsmtty_cleanup(struct tty_struct *tty)
4094{
4095 struct gsm_dlci *dlci = tty->driver_data;
4096 struct gsm_mux *gsm = dlci->gsm;
4097
4098 dlci_put(dlci);
4099 dlci_put(gsm->dlci[0]);
4100 mux_put(gsm);
4101}
4102
4103/* Virtual ttys for the demux */
4104static const struct tty_operations gsmtty_ops = {
4105 .install = gsmtty_install,
4106 .open = gsmtty_open,
4107 .close = gsmtty_close,
4108 .write = gsmtty_write,
4109 .write_room = gsmtty_write_room,
4110 .chars_in_buffer = gsmtty_chars_in_buffer,
4111 .flush_buffer = gsmtty_flush_buffer,
4112 .ioctl = gsmtty_ioctl,
4113 .throttle = gsmtty_throttle,
4114 .unthrottle = gsmtty_unthrottle,
4115 .set_termios = gsmtty_set_termios,
4116 .hangup = gsmtty_hangup,
4117 .wait_until_sent = gsmtty_wait_until_sent,
4118 .tiocmget = gsmtty_tiocmget,
4119 .tiocmset = gsmtty_tiocmset,
4120 .break_ctl = gsmtty_break_ctl,
4121 .cleanup = gsmtty_cleanup,
4122};
4123
4124
4125
4126static int __init gsm_init(void)
4127{
4128 /* Fill in our line protocol discipline, and register it */
4129 int status = tty_register_ldisc(&tty_ldisc_packet);
4130 if (status != 0) {
4131 pr_err("n_gsm: can't register line discipline (err = %d)\n",
4132 status);
4133 return status;
4134 }
4135
4136 gsm_tty_driver = tty_alloc_driver(GSM_TTY_MINORS, TTY_DRIVER_REAL_RAW |
4137 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_HARDWARE_BREAK);
4138 if (IS_ERR(gsm_tty_driver)) {
4139 pr_err("gsm_init: tty allocation failed.\n");
4140 status = PTR_ERR(gsm_tty_driver);
4141 goto err_unreg_ldisc;
4142 }
4143 gsm_tty_driver->driver_name = "gsmtty";
4144 gsm_tty_driver->name = "gsmtty";
4145 gsm_tty_driver->major = 0; /* Dynamic */
4146 gsm_tty_driver->minor_start = 0;
4147 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
4148 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
4149 gsm_tty_driver->init_termios = tty_std_termios;
4150 /* Fixme */
4151 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
4152 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
4153
4154 if (tty_register_driver(gsm_tty_driver)) {
4155 pr_err("gsm_init: tty registration failed.\n");
4156 status = -EBUSY;
4157 goto err_put_driver;
4158 }
4159 pr_debug("gsm_init: loaded as %d,%d.\n",
4160 gsm_tty_driver->major, gsm_tty_driver->minor_start);
4161 return 0;
4162err_put_driver:
4163 tty_driver_kref_put(gsm_tty_driver);
4164err_unreg_ldisc:
4165 tty_unregister_ldisc(&tty_ldisc_packet);
4166 return status;
4167}
4168
4169static void __exit gsm_exit(void)
4170{
4171 tty_unregister_ldisc(&tty_ldisc_packet);
4172 tty_unregister_driver(gsm_tty_driver);
4173 tty_driver_kref_put(gsm_tty_driver);
4174}
4175
4176module_init(gsm_init);
4177module_exit(gsm_exit);
4178
4179
4180MODULE_LICENSE("GPL");
4181MODULE_ALIAS_LDISC(N_GSM0710);
1/*
2 * n_gsm.c GSM 0710 tty multiplexor
3 * Copyright (c) 2009/10 Intel Corporation
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 *
18 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
19 *
20 * TO DO:
21 * Mostly done: ioctls for setting modes/timing
22 * Partly done: hooks so you can pull off frames to non tty devs
23 * Restart DLCI 0 when it closes ?
24 * Improve the tx engine
25 * Resolve tx side locking by adding a queue_head and routing
26 * all control traffic via it
27 * General tidy/document
28 * Review the locking/move to refcounts more (mux now moved to an
29 * alloc/free model ready)
30 * Use newest tty open/close port helpers and install hooks
31 * What to do about power functions ?
32 * Termios setting and negotiation
33 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets
34 *
35 */
36
37#include <linux/types.h>
38#include <linux/major.h>
39#include <linux/errno.h>
40#include <linux/signal.h>
41#include <linux/fcntl.h>
42#include <linux/sched.h>
43#include <linux/interrupt.h>
44#include <linux/tty.h>
45#include <linux/ctype.h>
46#include <linux/mm.h>
47#include <linux/string.h>
48#include <linux/slab.h>
49#include <linux/poll.h>
50#include <linux/bitops.h>
51#include <linux/file.h>
52#include <linux/uaccess.h>
53#include <linux/module.h>
54#include <linux/timer.h>
55#include <linux/tty_flip.h>
56#include <linux/tty_driver.h>
57#include <linux/serial.h>
58#include <linux/kfifo.h>
59#include <linux/skbuff.h>
60#include <net/arp.h>
61#include <linux/ip.h>
62#include <linux/netdevice.h>
63#include <linux/etherdevice.h>
64#include <linux/gsmmux.h>
65
66static int debug;
67module_param(debug, int, 0600);
68
69/* Defaults: these are from the specification */
70
71#define T1 10 /* 100mS */
72#define T2 34 /* 333mS */
73#define N2 3 /* Retry 3 times */
74
75/* Use long timers for testing at low speed with debug on */
76#ifdef DEBUG_TIMING
77#define T1 100
78#define T2 200
79#endif
80
81/*
82 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
83 * limits so this is plenty
84 */
85#define MAX_MRU 1500
86#define MAX_MTU 1500
87#define GSM_NET_TX_TIMEOUT (HZ*10)
88
89/**
90 * struct gsm_mux_net - network interface
91 * @struct gsm_dlci* dlci
92 * @struct net_device_stats stats;
93 *
94 * Created when net interface is initialized.
95 **/
96struct gsm_mux_net {
97 struct kref ref;
98 struct gsm_dlci *dlci;
99 struct net_device_stats stats;
100};
101
102#define STATS(net) (((struct gsm_mux_net *)netdev_priv(net))->stats)
103
104/*
105 * Each block of data we have queued to go out is in the form of
106 * a gsm_msg which holds everything we need in a link layer independent
107 * format
108 */
109
110struct gsm_msg {
111 struct gsm_msg *next;
112 u8 addr; /* DLCI address + flags */
113 u8 ctrl; /* Control byte + flags */
114 unsigned int len; /* Length of data block (can be zero) */
115 unsigned char *data; /* Points into buffer but not at the start */
116 unsigned char buffer[0];
117};
118
119/*
120 * Each active data link has a gsm_dlci structure associated which ties
121 * the link layer to an optional tty (if the tty side is open). To avoid
122 * complexity right now these are only ever freed up when the mux is
123 * shut down.
124 *
125 * At the moment we don't free DLCI objects until the mux is torn down
126 * this avoid object life time issues but might be worth review later.
127 */
128
129struct gsm_dlci {
130 struct gsm_mux *gsm;
131 int addr;
132 int state;
133#define DLCI_CLOSED 0
134#define DLCI_OPENING 1 /* Sending SABM not seen UA */
135#define DLCI_OPEN 2 /* SABM/UA complete */
136#define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
137 struct kref ref; /* freed from port or mux close */
138 struct mutex mutex;
139
140 /* Link layer */
141 spinlock_t lock; /* Protects the internal state */
142 struct timer_list t1; /* Retransmit timer for SABM and UA */
143 int retries;
144 /* Uplink tty if active */
145 struct tty_port port; /* The tty bound to this DLCI if there is one */
146 struct kfifo *fifo; /* Queue fifo for the DLCI */
147 struct kfifo _fifo; /* For new fifo API porting only */
148 int adaption; /* Adaption layer in use */
149 int prev_adaption;
150 u32 modem_rx; /* Our incoming virtual modem lines */
151 u32 modem_tx; /* Our outgoing modem lines */
152 int dead; /* Refuse re-open */
153 /* Flow control */
154 int throttled; /* Private copy of throttle state */
155 int constipated; /* Throttle status for outgoing */
156 /* Packetised I/O */
157 struct sk_buff *skb; /* Frame being sent */
158 struct sk_buff_head skb_list; /* Queued frames */
159 /* Data handling callback */
160 void (*data)(struct gsm_dlci *dlci, u8 *data, int len);
161 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len);
162 struct net_device *net; /* network interface, if created */
163};
164
165/* DLCI 0, 62/63 are special or reseved see gsmtty_open */
166
167#define NUM_DLCI 64
168
169/*
170 * DLCI 0 is used to pass control blocks out of band of the data
171 * flow (and with a higher link priority). One command can be outstanding
172 * at a time and we use this structure to manage them. They are created
173 * and destroyed by the user context, and updated by the receive paths
174 * and timers
175 */
176
177struct gsm_control {
178 u8 cmd; /* Command we are issuing */
179 u8 *data; /* Data for the command in case we retransmit */
180 int len; /* Length of block for retransmission */
181 int done; /* Done flag */
182 int error; /* Error if any */
183};
184
185/*
186 * Each GSM mux we have is represented by this structure. If we are
187 * operating as an ldisc then we use this structure as our ldisc
188 * state. We need to sort out lifetimes and locking with respect
189 * to the gsm mux array. For now we don't free DLCI objects that
190 * have been instantiated until the mux itself is terminated.
191 *
192 * To consider further: tty open versus mux shutdown.
193 */
194
195struct gsm_mux {
196 struct tty_struct *tty; /* The tty our ldisc is bound to */
197 spinlock_t lock;
198 unsigned int num;
199 struct kref ref;
200
201 /* Events on the GSM channel */
202 wait_queue_head_t event;
203
204 /* Bits for GSM mode decoding */
205
206 /* Framing Layer */
207 unsigned char *buf;
208 int state;
209#define GSM_SEARCH 0
210#define GSM_START 1
211#define GSM_ADDRESS 2
212#define GSM_CONTROL 3
213#define GSM_LEN 4
214#define GSM_DATA 5
215#define GSM_FCS 6
216#define GSM_OVERRUN 7
217#define GSM_LEN0 8
218#define GSM_LEN1 9
219#define GSM_SSOF 10
220 unsigned int len;
221 unsigned int address;
222 unsigned int count;
223 int escape;
224 int encoding;
225 u8 control;
226 u8 fcs;
227 u8 received_fcs;
228 u8 *txframe; /* TX framing buffer */
229
230 /* Methods for the receiver side */
231 void (*receive)(struct gsm_mux *gsm, u8 ch);
232 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag);
233 /* And transmit side */
234 int (*output)(struct gsm_mux *mux, u8 *data, int len);
235
236 /* Link Layer */
237 unsigned int mru;
238 unsigned int mtu;
239 int initiator; /* Did we initiate connection */
240 int dead; /* Has the mux been shut down */
241 struct gsm_dlci *dlci[NUM_DLCI];
242 int constipated; /* Asked by remote to shut up */
243
244 spinlock_t tx_lock;
245 unsigned int tx_bytes; /* TX data outstanding */
246#define TX_THRESH_HI 8192
247#define TX_THRESH_LO 2048
248 struct gsm_msg *tx_head; /* Pending data packets */
249 struct gsm_msg *tx_tail;
250
251 /* Control messages */
252 struct timer_list t2_timer; /* Retransmit timer for commands */
253 int cretries; /* Command retry counter */
254 struct gsm_control *pending_cmd;/* Our current pending command */
255 spinlock_t control_lock; /* Protects the pending command */
256
257 /* Configuration */
258 int adaption; /* 1 or 2 supported */
259 u8 ftype; /* UI or UIH */
260 int t1, t2; /* Timers in 1/100th of a sec */
261 int n2; /* Retry count */
262
263 /* Statistics (not currently exposed) */
264 unsigned long bad_fcs;
265 unsigned long malformed;
266 unsigned long io_error;
267 unsigned long bad_size;
268 unsigned long unsupported;
269};
270
271
272/*
273 * Mux objects - needed so that we can translate a tty index into the
274 * relevant mux and DLCI.
275 */
276
277#define MAX_MUX 4 /* 256 minors */
278static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
279static spinlock_t gsm_mux_lock;
280
281static struct tty_driver *gsm_tty_driver;
282
283/*
284 * This section of the driver logic implements the GSM encodings
285 * both the basic and the 'advanced'. Reliable transport is not
286 * supported.
287 */
288
289#define CR 0x02
290#define EA 0x01
291#define PF 0x10
292
293/* I is special: the rest are ..*/
294#define RR 0x01
295#define UI 0x03
296#define RNR 0x05
297#define REJ 0x09
298#define DM 0x0F
299#define SABM 0x2F
300#define DISC 0x43
301#define UA 0x63
302#define UIH 0xEF
303
304/* Channel commands */
305#define CMD_NSC 0x09
306#define CMD_TEST 0x11
307#define CMD_PSC 0x21
308#define CMD_RLS 0x29
309#define CMD_FCOFF 0x31
310#define CMD_PN 0x41
311#define CMD_RPN 0x49
312#define CMD_FCON 0x51
313#define CMD_CLD 0x61
314#define CMD_SNC 0x69
315#define CMD_MSC 0x71
316
317/* Virtual modem bits */
318#define MDM_FC 0x01
319#define MDM_RTC 0x02
320#define MDM_RTR 0x04
321#define MDM_IC 0x20
322#define MDM_DV 0x40
323
324#define GSM0_SOF 0xF9
325#define GSM1_SOF 0x7E
326#define GSM1_ESCAPE 0x7D
327#define GSM1_ESCAPE_BITS 0x20
328#define XON 0x11
329#define XOFF 0x13
330
331static const struct tty_port_operations gsm_port_ops;
332
333/*
334 * CRC table for GSM 0710
335 */
336
337static const u8 gsm_fcs8[256] = {
338 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
339 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
340 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
341 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
342 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
343 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
344 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
345 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
346 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
347 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
348 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
349 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
350 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
351 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
352 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
353 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
354 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
355 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
356 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
357 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
358 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
359 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
360 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
361 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
362 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
363 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
364 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
365 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
366 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
367 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
368 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
369 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
370};
371
372#define INIT_FCS 0xFF
373#define GOOD_FCS 0xCF
374
375/**
376 * gsm_fcs_add - update FCS
377 * @fcs: Current FCS
378 * @c: Next data
379 *
380 * Update the FCS to include c. Uses the algorithm in the specification
381 * notes.
382 */
383
384static inline u8 gsm_fcs_add(u8 fcs, u8 c)
385{
386 return gsm_fcs8[fcs ^ c];
387}
388
389/**
390 * gsm_fcs_add_block - update FCS for a block
391 * @fcs: Current FCS
392 * @c: buffer of data
393 * @len: length of buffer
394 *
395 * Update the FCS to include c. Uses the algorithm in the specification
396 * notes.
397 */
398
399static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
400{
401 while (len--)
402 fcs = gsm_fcs8[fcs ^ *c++];
403 return fcs;
404}
405
406/**
407 * gsm_read_ea - read a byte into an EA
408 * @val: variable holding value
409 * c: byte going into the EA
410 *
411 * Processes one byte of an EA. Updates the passed variable
412 * and returns 1 if the EA is now completely read
413 */
414
415static int gsm_read_ea(unsigned int *val, u8 c)
416{
417 /* Add the next 7 bits into the value */
418 *val <<= 7;
419 *val |= c >> 1;
420 /* Was this the last byte of the EA 1 = yes*/
421 return c & EA;
422}
423
424/**
425 * gsm_encode_modem - encode modem data bits
426 * @dlci: DLCI to encode from
427 *
428 * Returns the correct GSM encoded modem status bits (6 bit field) for
429 * the current status of the DLCI and attached tty object
430 */
431
432static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
433{
434 u8 modembits = 0;
435 /* FC is true flow control not modem bits */
436 if (dlci->throttled)
437 modembits |= MDM_FC;
438 if (dlci->modem_tx & TIOCM_DTR)
439 modembits |= MDM_RTC;
440 if (dlci->modem_tx & TIOCM_RTS)
441 modembits |= MDM_RTR;
442 if (dlci->modem_tx & TIOCM_RI)
443 modembits |= MDM_IC;
444 if (dlci->modem_tx & TIOCM_CD)
445 modembits |= MDM_DV;
446 return modembits;
447}
448
449/**
450 * gsm_print_packet - display a frame for debug
451 * @hdr: header to print before decode
452 * @addr: address EA from the frame
453 * @cr: C/R bit from the frame
454 * @control: control including PF bit
455 * @data: following data bytes
456 * @dlen: length of data
457 *
458 * Displays a packet in human readable format for debugging purposes. The
459 * style is based on amateur radio LAP-B dump display.
460 */
461
462static void gsm_print_packet(const char *hdr, int addr, int cr,
463 u8 control, const u8 *data, int dlen)
464{
465 if (!(debug & 1))
466 return;
467
468 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
469
470 switch (control & ~PF) {
471 case SABM:
472 pr_cont("SABM");
473 break;
474 case UA:
475 pr_cont("UA");
476 break;
477 case DISC:
478 pr_cont("DISC");
479 break;
480 case DM:
481 pr_cont("DM");
482 break;
483 case UI:
484 pr_cont("UI");
485 break;
486 case UIH:
487 pr_cont("UIH");
488 break;
489 default:
490 if (!(control & 0x01)) {
491 pr_cont("I N(S)%d N(R)%d",
492 (control & 0x0E) >> 1, (control & 0xE) >> 5);
493 } else switch (control & 0x0F) {
494 case RR:
495 pr_cont("RR(%d)", (control & 0xE0) >> 5);
496 break;
497 case RNR:
498 pr_cont("RNR(%d)", (control & 0xE0) >> 5);
499 break;
500 case REJ:
501 pr_cont("REJ(%d)", (control & 0xE0) >> 5);
502 break;
503 default:
504 pr_cont("[%02X]", control);
505 }
506 }
507
508 if (control & PF)
509 pr_cont("(P)");
510 else
511 pr_cont("(F)");
512
513 if (dlen) {
514 int ct = 0;
515 while (dlen--) {
516 if (ct % 8 == 0) {
517 pr_cont("\n");
518 pr_debug(" ");
519 }
520 pr_cont("%02X ", *data++);
521 ct++;
522 }
523 }
524 pr_cont("\n");
525}
526
527
528/*
529 * Link level transmission side
530 */
531
532/**
533 * gsm_stuff_packet - bytestuff a packet
534 * @ibuf: input
535 * @obuf: output
536 * @len: length of input
537 *
538 * Expand a buffer by bytestuffing it. The worst case size change
539 * is doubling and the caller is responsible for handing out
540 * suitable sized buffers.
541 */
542
543static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
544{
545 int olen = 0;
546 while (len--) {
547 if (*input == GSM1_SOF || *input == GSM1_ESCAPE
548 || *input == XON || *input == XOFF) {
549 *output++ = GSM1_ESCAPE;
550 *output++ = *input++ ^ GSM1_ESCAPE_BITS;
551 olen++;
552 } else
553 *output++ = *input++;
554 olen++;
555 }
556 return olen;
557}
558
559/**
560 * gsm_send - send a control frame
561 * @gsm: our GSM mux
562 * @addr: address for control frame
563 * @cr: command/response bit
564 * @control: control byte including PF bit
565 *
566 * Format up and transmit a control frame. These do not go via the
567 * queueing logic as they should be transmitted ahead of data when
568 * they are needed.
569 *
570 * FIXME: Lock versus data TX path
571 */
572
573static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
574{
575 int len;
576 u8 cbuf[10];
577 u8 ibuf[3];
578
579 switch (gsm->encoding) {
580 case 0:
581 cbuf[0] = GSM0_SOF;
582 cbuf[1] = (addr << 2) | (cr << 1) | EA;
583 cbuf[2] = control;
584 cbuf[3] = EA; /* Length of data = 0 */
585 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
586 cbuf[5] = GSM0_SOF;
587 len = 6;
588 break;
589 case 1:
590 case 2:
591 /* Control frame + packing (but not frame stuffing) in mode 1 */
592 ibuf[0] = (addr << 2) | (cr << 1) | EA;
593 ibuf[1] = control;
594 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
595 /* Stuffing may double the size worst case */
596 len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
597 /* Now add the SOF markers */
598 cbuf[0] = GSM1_SOF;
599 cbuf[len + 1] = GSM1_SOF;
600 /* FIXME: we can omit the lead one in many cases */
601 len += 2;
602 break;
603 default:
604 WARN_ON(1);
605 return;
606 }
607 gsm->output(gsm, cbuf, len);
608 gsm_print_packet("-->", addr, cr, control, NULL, 0);
609}
610
611/**
612 * gsm_response - send a control response
613 * @gsm: our GSM mux
614 * @addr: address for control frame
615 * @control: control byte including PF bit
616 *
617 * Format up and transmit a link level response frame.
618 */
619
620static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
621{
622 gsm_send(gsm, addr, 0, control);
623}
624
625/**
626 * gsm_command - send a control command
627 * @gsm: our GSM mux
628 * @addr: address for control frame
629 * @control: control byte including PF bit
630 *
631 * Format up and transmit a link level command frame.
632 */
633
634static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
635{
636 gsm_send(gsm, addr, 1, control);
637}
638
639/* Data transmission */
640
641#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
642
643/**
644 * gsm_data_alloc - allocate data frame
645 * @gsm: GSM mux
646 * @addr: DLCI address
647 * @len: length excluding header and FCS
648 * @ctrl: control byte
649 *
650 * Allocate a new data buffer for sending frames with data. Space is left
651 * at the front for header bytes but that is treated as an implementation
652 * detail and not for the high level code to use
653 */
654
655static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
656 u8 ctrl)
657{
658 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
659 GFP_ATOMIC);
660 if (m == NULL)
661 return NULL;
662 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
663 m->len = len;
664 m->addr = addr;
665 m->ctrl = ctrl;
666 m->next = NULL;
667 return m;
668}
669
670/**
671 * gsm_data_kick - poke the queue
672 * @gsm: GSM Mux
673 *
674 * The tty device has called us to indicate that room has appeared in
675 * the transmit queue. Ram more data into the pipe if we have any
676 *
677 * FIXME: lock against link layer control transmissions
678 */
679
680static void gsm_data_kick(struct gsm_mux *gsm)
681{
682 struct gsm_msg *msg = gsm->tx_head;
683 int len;
684 int skip_sof = 0;
685
686 /* FIXME: We need to apply this solely to data messages */
687 if (gsm->constipated)
688 return;
689
690 while (gsm->tx_head != NULL) {
691 msg = gsm->tx_head;
692 if (gsm->encoding != 0) {
693 gsm->txframe[0] = GSM1_SOF;
694 len = gsm_stuff_frame(msg->data,
695 gsm->txframe + 1, msg->len);
696 gsm->txframe[len + 1] = GSM1_SOF;
697 len += 2;
698 } else {
699 gsm->txframe[0] = GSM0_SOF;
700 memcpy(gsm->txframe + 1 , msg->data, msg->len);
701 gsm->txframe[msg->len + 1] = GSM0_SOF;
702 len = msg->len + 2;
703 }
704
705 if (debug & 4)
706 print_hex_dump_bytes("gsm_data_kick: ",
707 DUMP_PREFIX_OFFSET,
708 gsm->txframe, len);
709
710 if (gsm->output(gsm, gsm->txframe + skip_sof,
711 len - skip_sof) < 0)
712 break;
713 /* FIXME: Can eliminate one SOF in many more cases */
714 gsm->tx_head = msg->next;
715 if (gsm->tx_head == NULL)
716 gsm->tx_tail = NULL;
717 gsm->tx_bytes -= msg->len;
718 kfree(msg);
719 /* For a burst of frames skip the extra SOF within the
720 burst */
721 skip_sof = 1;
722 }
723}
724
725/**
726 * __gsm_data_queue - queue a UI or UIH frame
727 * @dlci: DLCI sending the data
728 * @msg: message queued
729 *
730 * Add data to the transmit queue and try and get stuff moving
731 * out of the mux tty if not already doing so. The Caller must hold
732 * the gsm tx lock.
733 */
734
735static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
736{
737 struct gsm_mux *gsm = dlci->gsm;
738 u8 *dp = msg->data;
739 u8 *fcs = dp + msg->len;
740
741 /* Fill in the header */
742 if (gsm->encoding == 0) {
743 if (msg->len < 128)
744 *--dp = (msg->len << 1) | EA;
745 else {
746 *--dp = (msg->len >> 7); /* bits 7 - 15 */
747 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
748 }
749 }
750
751 *--dp = msg->ctrl;
752 if (gsm->initiator)
753 *--dp = (msg->addr << 2) | 2 | EA;
754 else
755 *--dp = (msg->addr << 2) | EA;
756 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
757 /* Ugly protocol layering violation */
758 if (msg->ctrl == UI || msg->ctrl == (UI|PF))
759 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
760 *fcs = 0xFF - *fcs;
761
762 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
763 msg->data, msg->len);
764
765 /* Move the header back and adjust the length, also allow for the FCS
766 now tacked on the end */
767 msg->len += (msg->data - dp) + 1;
768 msg->data = dp;
769
770 /* Add to the actual output queue */
771 if (gsm->tx_tail)
772 gsm->tx_tail->next = msg;
773 else
774 gsm->tx_head = msg;
775 gsm->tx_tail = msg;
776 gsm->tx_bytes += msg->len;
777 gsm_data_kick(gsm);
778}
779
780/**
781 * gsm_data_queue - queue a UI or UIH frame
782 * @dlci: DLCI sending the data
783 * @msg: message queued
784 *
785 * Add data to the transmit queue and try and get stuff moving
786 * out of the mux tty if not already doing so. Take the
787 * the gsm tx lock and dlci lock.
788 */
789
790static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
791{
792 unsigned long flags;
793 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
794 __gsm_data_queue(dlci, msg);
795 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
796}
797
798/**
799 * gsm_dlci_data_output - try and push data out of a DLCI
800 * @gsm: mux
801 * @dlci: the DLCI to pull data from
802 *
803 * Pull data from a DLCI and send it into the transmit queue if there
804 * is data. Keep to the MRU of the mux. This path handles the usual tty
805 * interface which is a byte stream with optional modem data.
806 *
807 * Caller must hold the tx_lock of the mux.
808 */
809
810static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
811{
812 struct gsm_msg *msg;
813 u8 *dp;
814 int len, total_size, size;
815 int h = dlci->adaption - 1;
816
817 total_size = 0;
818 while(1) {
819 len = kfifo_len(dlci->fifo);
820 if (len == 0)
821 return total_size;
822
823 /* MTU/MRU count only the data bits */
824 if (len > gsm->mtu)
825 len = gsm->mtu;
826
827 size = len + h;
828
829 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
830 /* FIXME: need a timer or something to kick this so it can't
831 get stuck with no work outstanding and no buffer free */
832 if (msg == NULL)
833 return -ENOMEM;
834 dp = msg->data;
835 switch (dlci->adaption) {
836 case 1: /* Unstructured */
837 break;
838 case 2: /* Unstructed with modem bits. Always one byte as we never
839 send inline break data */
840 *dp++ = gsm_encode_modem(dlci);
841 break;
842 }
843 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len);
844 __gsm_data_queue(dlci, msg);
845 total_size += size;
846 }
847 /* Bytes of data we used up */
848 return total_size;
849}
850
851/**
852 * gsm_dlci_data_output_framed - try and push data out of a DLCI
853 * @gsm: mux
854 * @dlci: the DLCI to pull data from
855 *
856 * Pull data from a DLCI and send it into the transmit queue if there
857 * is data. Keep to the MRU of the mux. This path handles framed data
858 * queued as skbuffs to the DLCI.
859 *
860 * Caller must hold the tx_lock of the mux.
861 */
862
863static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
864 struct gsm_dlci *dlci)
865{
866 struct gsm_msg *msg;
867 u8 *dp;
868 int len, size;
869 int last = 0, first = 0;
870 int overhead = 0;
871
872 /* One byte per frame is used for B/F flags */
873 if (dlci->adaption == 4)
874 overhead = 1;
875
876 /* dlci->skb is locked by tx_lock */
877 if (dlci->skb == NULL) {
878 dlci->skb = skb_dequeue_tail(&dlci->skb_list);
879 if (dlci->skb == NULL)
880 return 0;
881 first = 1;
882 }
883 len = dlci->skb->len + overhead;
884
885 /* MTU/MRU count only the data bits */
886 if (len > gsm->mtu) {
887 if (dlci->adaption == 3) {
888 /* Over long frame, bin it */
889 kfree_skb(dlci->skb);
890 dlci->skb = NULL;
891 return 0;
892 }
893 len = gsm->mtu;
894 } else
895 last = 1;
896
897 size = len + overhead;
898 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
899
900 /* FIXME: need a timer or something to kick this so it can't
901 get stuck with no work outstanding and no buffer free */
902 if (msg == NULL) {
903 skb_queue_tail(&dlci->skb_list, dlci->skb);
904 dlci->skb = NULL;
905 return -ENOMEM;
906 }
907 dp = msg->data;
908
909 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
910 /* Flag byte to carry the start/end info */
911 *dp++ = last << 7 | first << 6 | 1; /* EA */
912 len--;
913 }
914 memcpy(dp, dlci->skb->data, len);
915 skb_pull(dlci->skb, len);
916 __gsm_data_queue(dlci, msg);
917 if (last) {
918 kfree_skb(dlci->skb);
919 dlci->skb = NULL;
920 }
921 return size;
922}
923
924/**
925 * gsm_dlci_data_sweep - look for data to send
926 * @gsm: the GSM mux
927 *
928 * Sweep the GSM mux channels in priority order looking for ones with
929 * data to send. We could do with optimising this scan a bit. We aim
930 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
931 * TX_THRESH_LO we get called again
932 *
933 * FIXME: We should round robin between groups and in theory you can
934 * renegotiate DLCI priorities with optional stuff. Needs optimising.
935 */
936
937static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
938{
939 int len;
940 /* Priority ordering: We should do priority with RR of the groups */
941 int i = 1;
942
943 while (i < NUM_DLCI) {
944 struct gsm_dlci *dlci;
945
946 if (gsm->tx_bytes > TX_THRESH_HI)
947 break;
948 dlci = gsm->dlci[i];
949 if (dlci == NULL || dlci->constipated) {
950 i++;
951 continue;
952 }
953 if (dlci->adaption < 3 && !dlci->net)
954 len = gsm_dlci_data_output(gsm, dlci);
955 else
956 len = gsm_dlci_data_output_framed(gsm, dlci);
957 if (len < 0)
958 break;
959 /* DLCI empty - try the next */
960 if (len == 0)
961 i++;
962 }
963}
964
965/**
966 * gsm_dlci_data_kick - transmit if possible
967 * @dlci: DLCI to kick
968 *
969 * Transmit data from this DLCI if the queue is empty. We can't rely on
970 * a tty wakeup except when we filled the pipe so we need to fire off
971 * new data ourselves in other cases.
972 */
973
974static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
975{
976 unsigned long flags;
977 int sweep;
978
979 spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
980 /* If we have nothing running then we need to fire up */
981 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
982 if (dlci->gsm->tx_bytes == 0) {
983 if (dlci->net)
984 gsm_dlci_data_output_framed(dlci->gsm, dlci);
985 else
986 gsm_dlci_data_output(dlci->gsm, dlci);
987 }
988 if (sweep)
989 gsm_dlci_data_sweep(dlci->gsm);
990 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
991}
992
993/*
994 * Control message processing
995 */
996
997
998/**
999 * gsm_control_reply - send a response frame to a control
1000 * @gsm: gsm channel
1001 * @cmd: the command to use
1002 * @data: data to follow encoded info
1003 * @dlen: length of data
1004 *
1005 * Encode up and queue a UI/UIH frame containing our response.
1006 */
1007
1008static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data,
1009 int dlen)
1010{
1011 struct gsm_msg *msg;
1012 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
1013 if (msg == NULL)
1014 return;
1015 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
1016 msg->data[1] = (dlen << 1) | EA;
1017 memcpy(msg->data + 2, data, dlen);
1018 gsm_data_queue(gsm->dlci[0], msg);
1019}
1020
1021/**
1022 * gsm_process_modem - process received modem status
1023 * @tty: virtual tty bound to the DLCI
1024 * @dlci: DLCI to affect
1025 * @modem: modem bits (full EA)
1026 *
1027 * Used when a modem control message or line state inline in adaption
1028 * layer 2 is processed. Sort out the local modem state and throttles
1029 */
1030
1031static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
1032 u32 modem, int clen)
1033{
1034 int mlines = 0;
1035 u8 brk = 0;
1036
1037 /* The modem status command can either contain one octet (v.24 signals)
1038 or two octets (v.24 signals + break signals). The length field will
1039 either be 2 or 3 respectively. This is specified in section
1040 5.4.6.3.7 of the 27.010 mux spec. */
1041
1042 if (clen == 2)
1043 modem = modem & 0x7f;
1044 else {
1045 brk = modem & 0x7f;
1046 modem = (modem >> 7) & 0x7f;
1047 };
1048
1049 /* Flow control/ready to communicate */
1050 if (modem & MDM_FC) {
1051 /* Need to throttle our output on this device */
1052 dlci->constipated = 1;
1053 }
1054 if (modem & MDM_RTC) {
1055 mlines |= TIOCM_DSR | TIOCM_DTR;
1056 dlci->constipated = 0;
1057 gsm_dlci_data_kick(dlci);
1058 }
1059 /* Map modem bits */
1060 if (modem & MDM_RTR)
1061 mlines |= TIOCM_RTS | TIOCM_CTS;
1062 if (modem & MDM_IC)
1063 mlines |= TIOCM_RI;
1064 if (modem & MDM_DV)
1065 mlines |= TIOCM_CD;
1066
1067 /* Carrier drop -> hangup */
1068 if (tty) {
1069 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
1070 if (!(tty->termios->c_cflag & CLOCAL))
1071 tty_hangup(tty);
1072 if (brk & 0x01)
1073 tty_insert_flip_char(tty, 0, TTY_BREAK);
1074 }
1075 dlci->modem_rx = mlines;
1076}
1077
1078/**
1079 * gsm_control_modem - modem status received
1080 * @gsm: GSM channel
1081 * @data: data following command
1082 * @clen: command length
1083 *
1084 * We have received a modem status control message. This is used by
1085 * the GSM mux protocol to pass virtual modem line status and optionally
1086 * to indicate break signals. Unpack it, convert to Linux representation
1087 * and if need be stuff a break message down the tty.
1088 */
1089
1090static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen)
1091{
1092 unsigned int addr = 0;
1093 unsigned int modem = 0;
1094 struct gsm_dlci *dlci;
1095 int len = clen;
1096 u8 *dp = data;
1097 struct tty_struct *tty;
1098
1099 while (gsm_read_ea(&addr, *dp++) == 0) {
1100 len--;
1101 if (len == 0)
1102 return;
1103 }
1104 /* Must be at least one byte following the EA */
1105 len--;
1106 if (len <= 0)
1107 return;
1108
1109 addr >>= 1;
1110 /* Closed port, or invalid ? */
1111 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1112 return;
1113 dlci = gsm->dlci[addr];
1114
1115 while (gsm_read_ea(&modem, *dp++) == 0) {
1116 len--;
1117 if (len == 0)
1118 return;
1119 }
1120 tty = tty_port_tty_get(&dlci->port);
1121 gsm_process_modem(tty, dlci, modem, clen);
1122 if (tty) {
1123 tty_wakeup(tty);
1124 tty_kref_put(tty);
1125 }
1126 gsm_control_reply(gsm, CMD_MSC, data, clen);
1127}
1128
1129/**
1130 * gsm_control_rls - remote line status
1131 * @gsm: GSM channel
1132 * @data: data bytes
1133 * @clen: data length
1134 *
1135 * The modem sends us a two byte message on the control channel whenever
1136 * it wishes to send us an error state from the virtual link. Stuff
1137 * this into the uplink tty if present
1138 */
1139
1140static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen)
1141{
1142 struct tty_struct *tty;
1143 unsigned int addr = 0 ;
1144 u8 bits;
1145 int len = clen;
1146 u8 *dp = data;
1147
1148 while (gsm_read_ea(&addr, *dp++) == 0) {
1149 len--;
1150 if (len == 0)
1151 return;
1152 }
1153 /* Must be at least one byte following ea */
1154 len--;
1155 if (len <= 0)
1156 return;
1157 addr >>= 1;
1158 /* Closed port, or invalid ? */
1159 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
1160 return;
1161 /* No error ? */
1162 bits = *dp;
1163 if ((bits & 1) == 0)
1164 return;
1165 /* See if we have an uplink tty */
1166 tty = tty_port_tty_get(&gsm->dlci[addr]->port);
1167
1168 if (tty) {
1169 if (bits & 2)
1170 tty_insert_flip_char(tty, 0, TTY_OVERRUN);
1171 if (bits & 4)
1172 tty_insert_flip_char(tty, 0, TTY_PARITY);
1173 if (bits & 8)
1174 tty_insert_flip_char(tty, 0, TTY_FRAME);
1175 tty_flip_buffer_push(tty);
1176 tty_kref_put(tty);
1177 }
1178 gsm_control_reply(gsm, CMD_RLS, data, clen);
1179}
1180
1181static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
1182
1183/**
1184 * gsm_control_message - DLCI 0 control processing
1185 * @gsm: our GSM mux
1186 * @command: the command EA
1187 * @data: data beyond the command/length EAs
1188 * @clen: length
1189 *
1190 * Input processor for control messages from the other end of the link.
1191 * Processes the incoming request and queues a response frame or an
1192 * NSC response if not supported
1193 */
1194
1195static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
1196 u8 *data, int clen)
1197{
1198 u8 buf[1];
1199 unsigned long flags;
1200
1201 switch (command) {
1202 case CMD_CLD: {
1203 struct gsm_dlci *dlci = gsm->dlci[0];
1204 /* Modem wishes to close down */
1205 if (dlci) {
1206 dlci->dead = 1;
1207 gsm->dead = 1;
1208 gsm_dlci_begin_close(dlci);
1209 }
1210 }
1211 break;
1212 case CMD_TEST:
1213 /* Modem wishes to test, reply with the data */
1214 gsm_control_reply(gsm, CMD_TEST, data, clen);
1215 break;
1216 case CMD_FCON:
1217 /* Modem wants us to STFU */
1218 gsm->constipated = 1;
1219 gsm_control_reply(gsm, CMD_FCON, NULL, 0);
1220 break;
1221 case CMD_FCOFF:
1222 /* Modem can accept data again */
1223 gsm->constipated = 0;
1224 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
1225 /* Kick the link in case it is idling */
1226 spin_lock_irqsave(&gsm->tx_lock, flags);
1227 gsm_data_kick(gsm);
1228 spin_unlock_irqrestore(&gsm->tx_lock, flags);
1229 break;
1230 case CMD_MSC:
1231 /* Out of band modem line change indicator for a DLCI */
1232 gsm_control_modem(gsm, data, clen);
1233 break;
1234 case CMD_RLS:
1235 /* Out of band error reception for a DLCI */
1236 gsm_control_rls(gsm, data, clen);
1237 break;
1238 case CMD_PSC:
1239 /* Modem wishes to enter power saving state */
1240 gsm_control_reply(gsm, CMD_PSC, NULL, 0);
1241 break;
1242 /* Optional unsupported commands */
1243 case CMD_PN: /* Parameter negotiation */
1244 case CMD_RPN: /* Remote port negotiation */
1245 case CMD_SNC: /* Service negotiation command */
1246 default:
1247 /* Reply to bad commands with an NSC */
1248 buf[0] = command;
1249 gsm_control_reply(gsm, CMD_NSC, buf, 1);
1250 break;
1251 }
1252}
1253
1254/**
1255 * gsm_control_response - process a response to our control
1256 * @gsm: our GSM mux
1257 * @command: the command (response) EA
1258 * @data: data beyond the command/length EA
1259 * @clen: length
1260 *
1261 * Process a response to an outstanding command. We only allow a single
1262 * control message in flight so this is fairly easy. All the clean up
1263 * is done by the caller, we just update the fields, flag it as done
1264 * and return
1265 */
1266
1267static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
1268 u8 *data, int clen)
1269{
1270 struct gsm_control *ctrl;
1271 unsigned long flags;
1272
1273 spin_lock_irqsave(&gsm->control_lock, flags);
1274
1275 ctrl = gsm->pending_cmd;
1276 /* Does the reply match our command */
1277 command |= 1;
1278 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
1279 /* Our command was replied to, kill the retry timer */
1280 del_timer(&gsm->t2_timer);
1281 gsm->pending_cmd = NULL;
1282 /* Rejected by the other end */
1283 if (command == CMD_NSC)
1284 ctrl->error = -EOPNOTSUPP;
1285 ctrl->done = 1;
1286 wake_up(&gsm->event);
1287 }
1288 spin_unlock_irqrestore(&gsm->control_lock, flags);
1289}
1290
1291/**
1292 * gsm_control_transmit - send control packet
1293 * @gsm: gsm mux
1294 * @ctrl: frame to send
1295 *
1296 * Send out a pending control command (called under control lock)
1297 */
1298
1299static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
1300{
1301 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype);
1302 if (msg == NULL)
1303 return;
1304 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */
1305 memcpy(msg->data + 1, ctrl->data, ctrl->len);
1306 gsm_data_queue(gsm->dlci[0], msg);
1307}
1308
1309/**
1310 * gsm_control_retransmit - retransmit a control frame
1311 * @data: pointer to our gsm object
1312 *
1313 * Called off the T2 timer expiry in order to retransmit control frames
1314 * that have been lost in the system somewhere. The control_lock protects
1315 * us from colliding with another sender or a receive completion event.
1316 * In that situation the timer may still occur in a small window but
1317 * gsm->pending_cmd will be NULL and we just let the timer expire.
1318 */
1319
1320static void gsm_control_retransmit(unsigned long data)
1321{
1322 struct gsm_mux *gsm = (struct gsm_mux *)data;
1323 struct gsm_control *ctrl;
1324 unsigned long flags;
1325 spin_lock_irqsave(&gsm->control_lock, flags);
1326 ctrl = gsm->pending_cmd;
1327 if (ctrl) {
1328 gsm->cretries--;
1329 if (gsm->cretries == 0) {
1330 gsm->pending_cmd = NULL;
1331 ctrl->error = -ETIMEDOUT;
1332 ctrl->done = 1;
1333 spin_unlock_irqrestore(&gsm->control_lock, flags);
1334 wake_up(&gsm->event);
1335 return;
1336 }
1337 gsm_control_transmit(gsm, ctrl);
1338 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1339 }
1340 spin_unlock_irqrestore(&gsm->control_lock, flags);
1341}
1342
1343/**
1344 * gsm_control_send - send a control frame on DLCI 0
1345 * @gsm: the GSM channel
1346 * @command: command to send including CR bit
1347 * @data: bytes of data (must be kmalloced)
1348 * @len: length of the block to send
1349 *
1350 * Queue and dispatch a control command. Only one command can be
1351 * active at a time. In theory more can be outstanding but the matching
1352 * gets really complicated so for now stick to one outstanding.
1353 */
1354
1355static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
1356 unsigned int command, u8 *data, int clen)
1357{
1358 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
1359 GFP_KERNEL);
1360 unsigned long flags;
1361 if (ctrl == NULL)
1362 return NULL;
1363retry:
1364 wait_event(gsm->event, gsm->pending_cmd == NULL);
1365 spin_lock_irqsave(&gsm->control_lock, flags);
1366 if (gsm->pending_cmd != NULL) {
1367 spin_unlock_irqrestore(&gsm->control_lock, flags);
1368 goto retry;
1369 }
1370 ctrl->cmd = command;
1371 ctrl->data = data;
1372 ctrl->len = clen;
1373 gsm->pending_cmd = ctrl;
1374 gsm->cretries = gsm->n2;
1375 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
1376 gsm_control_transmit(gsm, ctrl);
1377 spin_unlock_irqrestore(&gsm->control_lock, flags);
1378 return ctrl;
1379}
1380
1381/**
1382 * gsm_control_wait - wait for a control to finish
1383 * @gsm: GSM mux
1384 * @control: control we are waiting on
1385 *
1386 * Waits for the control to complete or time out. Frees any used
1387 * resources and returns 0 for success, or an error if the remote
1388 * rejected or ignored the request.
1389 */
1390
1391static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
1392{
1393 int err;
1394 wait_event(gsm->event, control->done == 1);
1395 err = control->error;
1396 kfree(control);
1397 return err;
1398}
1399
1400
1401/*
1402 * DLCI level handling: Needs krefs
1403 */
1404
1405/*
1406 * State transitions and timers
1407 */
1408
1409/**
1410 * gsm_dlci_close - a DLCI has closed
1411 * @dlci: DLCI that closed
1412 *
1413 * Perform processing when moving a DLCI into closed state. If there
1414 * is an attached tty this is hung up
1415 */
1416
1417static void gsm_dlci_close(struct gsm_dlci *dlci)
1418{
1419 del_timer(&dlci->t1);
1420 if (debug & 8)
1421 pr_debug("DLCI %d goes closed.\n", dlci->addr);
1422 dlci->state = DLCI_CLOSED;
1423 if (dlci->addr != 0) {
1424 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1425 if (tty) {
1426 tty_hangup(tty);
1427 tty_kref_put(tty);
1428 }
1429 kfifo_reset(dlci->fifo);
1430 } else
1431 dlci->gsm->dead = 1;
1432 wake_up(&dlci->gsm->event);
1433 /* A DLCI 0 close is a MUX termination so we need to kick that
1434 back to userspace somehow */
1435}
1436
1437/**
1438 * gsm_dlci_open - a DLCI has opened
1439 * @dlci: DLCI that opened
1440 *
1441 * Perform processing when moving a DLCI into open state.
1442 */
1443
1444static void gsm_dlci_open(struct gsm_dlci *dlci)
1445{
1446 /* Note that SABM UA .. SABM UA first UA lost can mean that we go
1447 open -> open */
1448 del_timer(&dlci->t1);
1449 /* This will let a tty open continue */
1450 dlci->state = DLCI_OPEN;
1451 if (debug & 8)
1452 pr_debug("DLCI %d goes open.\n", dlci->addr);
1453 wake_up(&dlci->gsm->event);
1454}
1455
1456/**
1457 * gsm_dlci_t1 - T1 timer expiry
1458 * @dlci: DLCI that opened
1459 *
1460 * The T1 timer handles retransmits of control frames (essentially of
1461 * SABM and DISC). We resend the command until the retry count runs out
1462 * in which case an opening port goes back to closed and a closing port
1463 * is simply put into closed state (any further frames from the other
1464 * end will get a DM response)
1465 */
1466
1467static void gsm_dlci_t1(unsigned long data)
1468{
1469 struct gsm_dlci *dlci = (struct gsm_dlci *)data;
1470 struct gsm_mux *gsm = dlci->gsm;
1471
1472 switch (dlci->state) {
1473 case DLCI_OPENING:
1474 dlci->retries--;
1475 if (dlci->retries) {
1476 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1477 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1478 } else
1479 gsm_dlci_close(dlci);
1480 break;
1481 case DLCI_CLOSING:
1482 dlci->retries--;
1483 if (dlci->retries) {
1484 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1485 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1486 } else
1487 gsm_dlci_close(dlci);
1488 break;
1489 }
1490}
1491
1492/**
1493 * gsm_dlci_begin_open - start channel open procedure
1494 * @dlci: DLCI to open
1495 *
1496 * Commence opening a DLCI from the Linux side. We issue SABM messages
1497 * to the modem which should then reply with a UA, at which point we
1498 * will move into open state. Opening is done asynchronously with retry
1499 * running off timers and the responses.
1500 */
1501
1502static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
1503{
1504 struct gsm_mux *gsm = dlci->gsm;
1505 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
1506 return;
1507 dlci->retries = gsm->n2;
1508 dlci->state = DLCI_OPENING;
1509 gsm_command(dlci->gsm, dlci->addr, SABM|PF);
1510 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1511}
1512
1513/**
1514 * gsm_dlci_begin_close - start channel open procedure
1515 * @dlci: DLCI to open
1516 *
1517 * Commence closing a DLCI from the Linux side. We issue DISC messages
1518 * to the modem which should then reply with a UA, at which point we
1519 * will move into closed state. Closing is done asynchronously with retry
1520 * off timers. We may also receive a DM reply from the other end which
1521 * indicates the channel was already closed.
1522 */
1523
1524static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
1525{
1526 struct gsm_mux *gsm = dlci->gsm;
1527 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
1528 return;
1529 dlci->retries = gsm->n2;
1530 dlci->state = DLCI_CLOSING;
1531 gsm_command(dlci->gsm, dlci->addr, DISC|PF);
1532 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
1533}
1534
1535/**
1536 * gsm_dlci_data - data arrived
1537 * @dlci: channel
1538 * @data: block of bytes received
1539 * @len: length of received block
1540 *
1541 * A UI or UIH frame has arrived which contains data for a channel
1542 * other than the control channel. If the relevant virtual tty is
1543 * open we shovel the bits down it, if not we drop them.
1544 */
1545
1546static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen)
1547{
1548 /* krefs .. */
1549 struct tty_port *port = &dlci->port;
1550 struct tty_struct *tty = tty_port_tty_get(port);
1551 unsigned int modem = 0;
1552 int len = clen;
1553
1554 if (debug & 16)
1555 pr_debug("%d bytes for tty %p\n", len, tty);
1556 if (tty) {
1557 switch (dlci->adaption) {
1558 /* Unsupported types */
1559 /* Packetised interruptible data */
1560 case 4:
1561 break;
1562 /* Packetised uininterruptible voice/data */
1563 case 3:
1564 break;
1565 /* Asynchronous serial with line state in each frame */
1566 case 2:
1567 while (gsm_read_ea(&modem, *data++) == 0) {
1568 len--;
1569 if (len == 0)
1570 return;
1571 }
1572 gsm_process_modem(tty, dlci, modem, clen);
1573 /* Line state will go via DLCI 0 controls only */
1574 case 1:
1575 default:
1576 tty_insert_flip_string(tty, data, len);
1577 tty_flip_buffer_push(tty);
1578 }
1579 tty_kref_put(tty);
1580 }
1581}
1582
1583/**
1584 * gsm_dlci_control - data arrived on control channel
1585 * @dlci: channel
1586 * @data: block of bytes received
1587 * @len: length of received block
1588 *
1589 * A UI or UIH frame has arrived which contains data for DLCI 0 the
1590 * control channel. This should contain a command EA followed by
1591 * control data bytes. The command EA contains a command/response bit
1592 * and we divide up the work accordingly.
1593 */
1594
1595static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len)
1596{
1597 /* See what command is involved */
1598 unsigned int command = 0;
1599 while (len-- > 0) {
1600 if (gsm_read_ea(&command, *data++) == 1) {
1601 int clen = *data++;
1602 len--;
1603 /* FIXME: this is properly an EA */
1604 clen >>= 1;
1605 /* Malformed command ? */
1606 if (clen > len)
1607 return;
1608 if (command & 1)
1609 gsm_control_message(dlci->gsm, command,
1610 data, clen);
1611 else
1612 gsm_control_response(dlci->gsm, command,
1613 data, clen);
1614 return;
1615 }
1616 }
1617}
1618
1619/*
1620 * Allocate/Free DLCI channels
1621 */
1622
1623/**
1624 * gsm_dlci_alloc - allocate a DLCI
1625 * @gsm: GSM mux
1626 * @addr: address of the DLCI
1627 *
1628 * Allocate and install a new DLCI object into the GSM mux.
1629 *
1630 * FIXME: review locking races
1631 */
1632
1633static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
1634{
1635 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
1636 if (dlci == NULL)
1637 return NULL;
1638 spin_lock_init(&dlci->lock);
1639 kref_init(&dlci->ref);
1640 mutex_init(&dlci->mutex);
1641 dlci->fifo = &dlci->_fifo;
1642 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
1643 kfree(dlci);
1644 return NULL;
1645 }
1646
1647 skb_queue_head_init(&dlci->skb_list);
1648 init_timer(&dlci->t1);
1649 dlci->t1.function = gsm_dlci_t1;
1650 dlci->t1.data = (unsigned long)dlci;
1651 tty_port_init(&dlci->port);
1652 dlci->port.ops = &gsm_port_ops;
1653 dlci->gsm = gsm;
1654 dlci->addr = addr;
1655 dlci->adaption = gsm->adaption;
1656 dlci->state = DLCI_CLOSED;
1657 if (addr)
1658 dlci->data = gsm_dlci_data;
1659 else
1660 dlci->data = gsm_dlci_command;
1661 gsm->dlci[addr] = dlci;
1662 return dlci;
1663}
1664
1665/**
1666 * gsm_dlci_free - free DLCI
1667 * @dlci: DLCI to free
1668 *
1669 * Free up a DLCI.
1670 *
1671 * Can sleep.
1672 */
1673static void gsm_dlci_free(struct kref *ref)
1674{
1675 struct gsm_dlci *dlci = container_of(ref, struct gsm_dlci, ref);
1676
1677 del_timer_sync(&dlci->t1);
1678 dlci->gsm->dlci[dlci->addr] = NULL;
1679 kfifo_free(dlci->fifo);
1680 while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
1681 kfree_skb(dlci->skb);
1682 kfree(dlci);
1683}
1684
1685static inline void dlci_get(struct gsm_dlci *dlci)
1686{
1687 kref_get(&dlci->ref);
1688}
1689
1690static inline void dlci_put(struct gsm_dlci *dlci)
1691{
1692 kref_put(&dlci->ref, gsm_dlci_free);
1693}
1694
1695/**
1696 * gsm_dlci_release - release DLCI
1697 * @dlci: DLCI to destroy
1698 *
1699 * Release a DLCI. Actual free is deferred until either
1700 * mux is closed or tty is closed - whichever is last.
1701 *
1702 * Can sleep.
1703 */
1704static void gsm_dlci_release(struct gsm_dlci *dlci)
1705{
1706 struct tty_struct *tty = tty_port_tty_get(&dlci->port);
1707 if (tty) {
1708 tty_vhangup(tty);
1709 tty_kref_put(tty);
1710 }
1711 dlci_put(dlci);
1712}
1713
1714/*
1715 * LAPBish link layer logic
1716 */
1717
1718/**
1719 * gsm_queue - a GSM frame is ready to process
1720 * @gsm: pointer to our gsm mux
1721 *
1722 * At this point in time a frame has arrived and been demangled from
1723 * the line encoding. All the differences between the encodings have
1724 * been handled below us and the frame is unpacked into the structures.
1725 * The fcs holds the header FCS but any data FCS must be added here.
1726 */
1727
1728static void gsm_queue(struct gsm_mux *gsm)
1729{
1730 struct gsm_dlci *dlci;
1731 u8 cr;
1732 int address;
1733 /* We have to sneak a look at the packet body to do the FCS.
1734 A somewhat layering violation in the spec */
1735
1736 if ((gsm->control & ~PF) == UI)
1737 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
1738 if (gsm->encoding == 0){
1739 /* WARNING: gsm->received_fcs is used for gsm->encoding = 0 only.
1740 In this case it contain the last piece of data
1741 required to generate final CRC */
1742 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
1743 }
1744 if (gsm->fcs != GOOD_FCS) {
1745 gsm->bad_fcs++;
1746 if (debug & 4)
1747 pr_debug("BAD FCS %02x\n", gsm->fcs);
1748 return;
1749 }
1750 address = gsm->address >> 1;
1751 if (address >= NUM_DLCI)
1752 goto invalid;
1753
1754 cr = gsm->address & 1; /* C/R bit */
1755
1756 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
1757
1758 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
1759 dlci = gsm->dlci[address];
1760
1761 switch (gsm->control) {
1762 case SABM|PF:
1763 if (cr == 0)
1764 goto invalid;
1765 if (dlci == NULL)
1766 dlci = gsm_dlci_alloc(gsm, address);
1767 if (dlci == NULL)
1768 return;
1769 if (dlci->dead)
1770 gsm_response(gsm, address, DM);
1771 else {
1772 gsm_response(gsm, address, UA);
1773 gsm_dlci_open(dlci);
1774 }
1775 break;
1776 case DISC|PF:
1777 if (cr == 0)
1778 goto invalid;
1779 if (dlci == NULL || dlci->state == DLCI_CLOSED) {
1780 gsm_response(gsm, address, DM);
1781 return;
1782 }
1783 /* Real close complete */
1784 gsm_response(gsm, address, UA);
1785 gsm_dlci_close(dlci);
1786 break;
1787 case UA:
1788 case UA|PF:
1789 if (cr == 0 || dlci == NULL)
1790 break;
1791 switch (dlci->state) {
1792 case DLCI_CLOSING:
1793 gsm_dlci_close(dlci);
1794 break;
1795 case DLCI_OPENING:
1796 gsm_dlci_open(dlci);
1797 break;
1798 }
1799 break;
1800 case DM: /* DM can be valid unsolicited */
1801 case DM|PF:
1802 if (cr)
1803 goto invalid;
1804 if (dlci == NULL)
1805 return;
1806 gsm_dlci_close(dlci);
1807 break;
1808 case UI:
1809 case UI|PF:
1810 case UIH:
1811 case UIH|PF:
1812#if 0
1813 if (cr)
1814 goto invalid;
1815#endif
1816 if (dlci == NULL || dlci->state != DLCI_OPEN) {
1817 gsm_command(gsm, address, DM|PF);
1818 return;
1819 }
1820 dlci->data(dlci, gsm->buf, gsm->len);
1821 break;
1822 default:
1823 goto invalid;
1824 }
1825 return;
1826invalid:
1827 gsm->malformed++;
1828 return;
1829}
1830
1831
1832/**
1833 * gsm0_receive - perform processing for non-transparency
1834 * @gsm: gsm data for this ldisc instance
1835 * @c: character
1836 *
1837 * Receive bytes in gsm mode 0
1838 */
1839
1840static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
1841{
1842 unsigned int len;
1843
1844 switch (gsm->state) {
1845 case GSM_SEARCH: /* SOF marker */
1846 if (c == GSM0_SOF) {
1847 gsm->state = GSM_ADDRESS;
1848 gsm->address = 0;
1849 gsm->len = 0;
1850 gsm->fcs = INIT_FCS;
1851 }
1852 break;
1853 case GSM_ADDRESS: /* Address EA */
1854 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1855 if (gsm_read_ea(&gsm->address, c))
1856 gsm->state = GSM_CONTROL;
1857 break;
1858 case GSM_CONTROL: /* Control Byte */
1859 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1860 gsm->control = c;
1861 gsm->state = GSM_LEN0;
1862 break;
1863 case GSM_LEN0: /* Length EA */
1864 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1865 if (gsm_read_ea(&gsm->len, c)) {
1866 if (gsm->len > gsm->mru) {
1867 gsm->bad_size++;
1868 gsm->state = GSM_SEARCH;
1869 break;
1870 }
1871 gsm->count = 0;
1872 if (!gsm->len)
1873 gsm->state = GSM_FCS;
1874 else
1875 gsm->state = GSM_DATA;
1876 break;
1877 }
1878 gsm->state = GSM_LEN1;
1879 break;
1880 case GSM_LEN1:
1881 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1882 len = c;
1883 gsm->len |= len << 7;
1884 if (gsm->len > gsm->mru) {
1885 gsm->bad_size++;
1886 gsm->state = GSM_SEARCH;
1887 break;
1888 }
1889 gsm->count = 0;
1890 if (!gsm->len)
1891 gsm->state = GSM_FCS;
1892 else
1893 gsm->state = GSM_DATA;
1894 break;
1895 case GSM_DATA: /* Data */
1896 gsm->buf[gsm->count++] = c;
1897 if (gsm->count == gsm->len)
1898 gsm->state = GSM_FCS;
1899 break;
1900 case GSM_FCS: /* FCS follows the packet */
1901 gsm->received_fcs = c;
1902 gsm_queue(gsm);
1903 gsm->state = GSM_SSOF;
1904 break;
1905 case GSM_SSOF:
1906 if (c == GSM0_SOF) {
1907 gsm->state = GSM_SEARCH;
1908 break;
1909 }
1910 break;
1911 }
1912}
1913
1914/**
1915 * gsm1_receive - perform processing for non-transparency
1916 * @gsm: gsm data for this ldisc instance
1917 * @c: character
1918 *
1919 * Receive bytes in mode 1 (Advanced option)
1920 */
1921
1922static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
1923{
1924 if (c == GSM1_SOF) {
1925 /* EOF is only valid in frame if we have got to the data state
1926 and received at least one byte (the FCS) */
1927 if (gsm->state == GSM_DATA && gsm->count) {
1928 /* Extract the FCS */
1929 gsm->count--;
1930 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
1931 gsm->len = gsm->count;
1932 gsm_queue(gsm);
1933 gsm->state = GSM_START;
1934 return;
1935 }
1936 /* Any partial frame was a runt so go back to start */
1937 if (gsm->state != GSM_START) {
1938 gsm->malformed++;
1939 gsm->state = GSM_START;
1940 }
1941 /* A SOF in GSM_START means we are still reading idling or
1942 framing bytes */
1943 return;
1944 }
1945
1946 if (c == GSM1_ESCAPE) {
1947 gsm->escape = 1;
1948 return;
1949 }
1950
1951 /* Only an unescaped SOF gets us out of GSM search */
1952 if (gsm->state == GSM_SEARCH)
1953 return;
1954
1955 if (gsm->escape) {
1956 c ^= GSM1_ESCAPE_BITS;
1957 gsm->escape = 0;
1958 }
1959 switch (gsm->state) {
1960 case GSM_START: /* First byte after SOF */
1961 gsm->address = 0;
1962 gsm->state = GSM_ADDRESS;
1963 gsm->fcs = INIT_FCS;
1964 /* Drop through */
1965 case GSM_ADDRESS: /* Address continuation */
1966 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1967 if (gsm_read_ea(&gsm->address, c))
1968 gsm->state = GSM_CONTROL;
1969 break;
1970 case GSM_CONTROL: /* Control Byte */
1971 gsm->fcs = gsm_fcs_add(gsm->fcs, c);
1972 gsm->control = c;
1973 gsm->count = 0;
1974 gsm->state = GSM_DATA;
1975 break;
1976 case GSM_DATA: /* Data */
1977 if (gsm->count > gsm->mru) { /* Allow one for the FCS */
1978 gsm->state = GSM_OVERRUN;
1979 gsm->bad_size++;
1980 } else
1981 gsm->buf[gsm->count++] = c;
1982 break;
1983 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
1984 break;
1985 }
1986}
1987
1988/**
1989 * gsm_error - handle tty error
1990 * @gsm: ldisc data
1991 * @data: byte received (may be invalid)
1992 * @flag: error received
1993 *
1994 * Handle an error in the receipt of data for a frame. Currently we just
1995 * go back to hunting for a SOF.
1996 *
1997 * FIXME: better diagnostics ?
1998 */
1999
2000static void gsm_error(struct gsm_mux *gsm,
2001 unsigned char data, unsigned char flag)
2002{
2003 gsm->state = GSM_SEARCH;
2004 gsm->io_error++;
2005}
2006
2007/**
2008 * gsm_cleanup_mux - generic GSM protocol cleanup
2009 * @gsm: our mux
2010 *
2011 * Clean up the bits of the mux which are the same for all framing
2012 * protocols. Remove the mux from the mux table, stop all the timers
2013 * and then shut down each device hanging up the channels as we go.
2014 */
2015
2016void gsm_cleanup_mux(struct gsm_mux *gsm)
2017{
2018 int i;
2019 struct gsm_dlci *dlci = gsm->dlci[0];
2020 struct gsm_msg *txq;
2021 struct gsm_control *gc;
2022
2023 gsm->dead = 1;
2024
2025 spin_lock(&gsm_mux_lock);
2026 for (i = 0; i < MAX_MUX; i++) {
2027 if (gsm_mux[i] == gsm) {
2028 gsm_mux[i] = NULL;
2029 break;
2030 }
2031 }
2032 spin_unlock(&gsm_mux_lock);
2033 WARN_ON(i == MAX_MUX);
2034
2035 /* In theory disconnecting DLCI 0 is sufficient but for some
2036 modems this is apparently not the case. */
2037 if (dlci) {
2038 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0);
2039 if (gc)
2040 gsm_control_wait(gsm, gc);
2041 }
2042 del_timer_sync(&gsm->t2_timer);
2043 /* Now we are sure T2 has stopped */
2044 if (dlci) {
2045 dlci->dead = 1;
2046 gsm_dlci_begin_close(dlci);
2047 wait_event_interruptible(gsm->event,
2048 dlci->state == DLCI_CLOSED);
2049 }
2050 /* Free up any link layer users */
2051 for (i = 0; i < NUM_DLCI; i++)
2052 if (gsm->dlci[i])
2053 gsm_dlci_release(gsm->dlci[i]);
2054 /* Now wipe the queues */
2055 for (txq = gsm->tx_head; txq != NULL; txq = gsm->tx_head) {
2056 gsm->tx_head = txq->next;
2057 kfree(txq);
2058 }
2059 gsm->tx_tail = NULL;
2060}
2061EXPORT_SYMBOL_GPL(gsm_cleanup_mux);
2062
2063/**
2064 * gsm_activate_mux - generic GSM setup
2065 * @gsm: our mux
2066 *
2067 * Set up the bits of the mux which are the same for all framing
2068 * protocols. Add the mux to the mux table so it can be opened and
2069 * finally kick off connecting to DLCI 0 on the modem.
2070 */
2071
2072int gsm_activate_mux(struct gsm_mux *gsm)
2073{
2074 struct gsm_dlci *dlci;
2075 int i = 0;
2076
2077 init_timer(&gsm->t2_timer);
2078 gsm->t2_timer.function = gsm_control_retransmit;
2079 gsm->t2_timer.data = (unsigned long)gsm;
2080 init_waitqueue_head(&gsm->event);
2081 spin_lock_init(&gsm->control_lock);
2082 spin_lock_init(&gsm->tx_lock);
2083
2084 if (gsm->encoding == 0)
2085 gsm->receive = gsm0_receive;
2086 else
2087 gsm->receive = gsm1_receive;
2088 gsm->error = gsm_error;
2089
2090 spin_lock(&gsm_mux_lock);
2091 for (i = 0; i < MAX_MUX; i++) {
2092 if (gsm_mux[i] == NULL) {
2093 gsm->num = i;
2094 gsm_mux[i] = gsm;
2095 break;
2096 }
2097 }
2098 spin_unlock(&gsm_mux_lock);
2099 if (i == MAX_MUX)
2100 return -EBUSY;
2101
2102 dlci = gsm_dlci_alloc(gsm, 0);
2103 if (dlci == NULL)
2104 return -ENOMEM;
2105 gsm->dead = 0; /* Tty opens are now permissible */
2106 return 0;
2107}
2108EXPORT_SYMBOL_GPL(gsm_activate_mux);
2109
2110/**
2111 * gsm_free_mux - free up a mux
2112 * @mux: mux to free
2113 *
2114 * Dispose of allocated resources for a dead mux
2115 */
2116void gsm_free_mux(struct gsm_mux *gsm)
2117{
2118 kfree(gsm->txframe);
2119 kfree(gsm->buf);
2120 kfree(gsm);
2121}
2122EXPORT_SYMBOL_GPL(gsm_free_mux);
2123
2124/**
2125 * gsm_free_muxr - free up a mux
2126 * @mux: mux to free
2127 *
2128 * Dispose of allocated resources for a dead mux
2129 */
2130static void gsm_free_muxr(struct kref *ref)
2131{
2132 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
2133 gsm_free_mux(gsm);
2134}
2135
2136static inline void mux_get(struct gsm_mux *gsm)
2137{
2138 kref_get(&gsm->ref);
2139}
2140
2141static inline void mux_put(struct gsm_mux *gsm)
2142{
2143 kref_put(&gsm->ref, gsm_free_muxr);
2144}
2145
2146/**
2147 * gsm_alloc_mux - allocate a mux
2148 *
2149 * Creates a new mux ready for activation.
2150 */
2151
2152struct gsm_mux *gsm_alloc_mux(void)
2153{
2154 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
2155 if (gsm == NULL)
2156 return NULL;
2157 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
2158 if (gsm->buf == NULL) {
2159 kfree(gsm);
2160 return NULL;
2161 }
2162 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL);
2163 if (gsm->txframe == NULL) {
2164 kfree(gsm->buf);
2165 kfree(gsm);
2166 return NULL;
2167 }
2168 spin_lock_init(&gsm->lock);
2169 kref_init(&gsm->ref);
2170
2171 gsm->t1 = T1;
2172 gsm->t2 = T2;
2173 gsm->n2 = N2;
2174 gsm->ftype = UIH;
2175 gsm->adaption = 1;
2176 gsm->encoding = 1;
2177 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
2178 gsm->mtu = 64;
2179 gsm->dead = 1; /* Avoid early tty opens */
2180
2181 return gsm;
2182}
2183EXPORT_SYMBOL_GPL(gsm_alloc_mux);
2184
2185/**
2186 * gsmld_output - write to link
2187 * @gsm: our mux
2188 * @data: bytes to output
2189 * @len: size
2190 *
2191 * Write a block of data from the GSM mux to the data channel. This
2192 * will eventually be serialized from above but at the moment isn't.
2193 */
2194
2195static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
2196{
2197 if (tty_write_room(gsm->tty) < len) {
2198 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
2199 return -ENOSPC;
2200 }
2201 if (debug & 4)
2202 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
2203 data, len);
2204 gsm->tty->ops->write(gsm->tty, data, len);
2205 return len;
2206}
2207
2208/**
2209 * gsmld_attach_gsm - mode set up
2210 * @tty: our tty structure
2211 * @gsm: our mux
2212 *
2213 * Set up the MUX for basic mode and commence connecting to the
2214 * modem. Currently called from the line discipline set up but
2215 * will need moving to an ioctl path.
2216 */
2217
2218static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2219{
2220 int ret, i;
2221 int base = gsm->num << 6; /* Base for this MUX */
2222
2223 gsm->tty = tty_kref_get(tty);
2224 gsm->output = gsmld_output;
2225 ret = gsm_activate_mux(gsm);
2226 if (ret != 0)
2227 tty_kref_put(gsm->tty);
2228 else {
2229 /* Don't register device 0 - this is the control channel and not
2230 a usable tty interface */
2231 for (i = 1; i < NUM_DLCI; i++)
2232 tty_register_device(gsm_tty_driver, base + i, NULL);
2233 }
2234 return ret;
2235}
2236
2237
2238/**
2239 * gsmld_detach_gsm - stop doing 0710 mux
2240 * @tty: tty attached to the mux
2241 * @gsm: mux
2242 *
2243 * Shutdown and then clean up the resources used by the line discipline
2244 */
2245
2246static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
2247{
2248 int i;
2249 int base = gsm->num << 6; /* Base for this MUX */
2250
2251 WARN_ON(tty != gsm->tty);
2252 for (i = 1; i < NUM_DLCI; i++)
2253 tty_unregister_device(gsm_tty_driver, base + i);
2254 gsm_cleanup_mux(gsm);
2255 tty_kref_put(gsm->tty);
2256 gsm->tty = NULL;
2257}
2258
2259static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
2260 char *fp, int count)
2261{
2262 struct gsm_mux *gsm = tty->disc_data;
2263 const unsigned char *dp;
2264 char *f;
2265 int i;
2266 char buf[64];
2267 char flags;
2268
2269 if (debug & 4)
2270 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
2271 cp, count);
2272
2273 for (i = count, dp = cp, f = fp; i; i--, dp++) {
2274 flags = *f++;
2275 switch (flags) {
2276 case TTY_NORMAL:
2277 gsm->receive(gsm, *dp);
2278 break;
2279 case TTY_OVERRUN:
2280 case TTY_BREAK:
2281 case TTY_PARITY:
2282 case TTY_FRAME:
2283 gsm->error(gsm, *dp, flags);
2284 break;
2285 default:
2286 WARN_ONCE("%s: unknown flag %d\n",
2287 tty_name(tty, buf), flags);
2288 break;
2289 }
2290 }
2291 /* FASYNC if needed ? */
2292 /* If clogged call tty_throttle(tty); */
2293}
2294
2295/**
2296 * gsmld_chars_in_buffer - report available bytes
2297 * @tty: tty device
2298 *
2299 * Report the number of characters buffered to be delivered to user
2300 * at this instant in time.
2301 *
2302 * Locking: gsm lock
2303 */
2304
2305static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty)
2306{
2307 return 0;
2308}
2309
2310/**
2311 * gsmld_flush_buffer - clean input queue
2312 * @tty: terminal device
2313 *
2314 * Flush the input buffer. Called when the line discipline is
2315 * being closed, when the tty layer wants the buffer flushed (eg
2316 * at hangup).
2317 */
2318
2319static void gsmld_flush_buffer(struct tty_struct *tty)
2320{
2321}
2322
2323/**
2324 * gsmld_close - close the ldisc for this tty
2325 * @tty: device
2326 *
2327 * Called from the terminal layer when this line discipline is
2328 * being shut down, either because of a close or becsuse of a
2329 * discipline change. The function will not be called while other
2330 * ldisc methods are in progress.
2331 */
2332
2333static void gsmld_close(struct tty_struct *tty)
2334{
2335 struct gsm_mux *gsm = tty->disc_data;
2336
2337 gsmld_detach_gsm(tty, gsm);
2338
2339 gsmld_flush_buffer(tty);
2340 /* Do other clean up here */
2341 mux_put(gsm);
2342}
2343
2344/**
2345 * gsmld_open - open an ldisc
2346 * @tty: terminal to open
2347 *
2348 * Called when this line discipline is being attached to the
2349 * terminal device. Can sleep. Called serialized so that no
2350 * other events will occur in parallel. No further open will occur
2351 * until a close.
2352 */
2353
2354static int gsmld_open(struct tty_struct *tty)
2355{
2356 struct gsm_mux *gsm;
2357
2358 if (tty->ops->write == NULL)
2359 return -EINVAL;
2360
2361 /* Attach our ldisc data */
2362 gsm = gsm_alloc_mux();
2363 if (gsm == NULL)
2364 return -ENOMEM;
2365
2366 tty->disc_data = gsm;
2367 tty->receive_room = 65536;
2368
2369 /* Attach the initial passive connection */
2370 gsm->encoding = 1;
2371 return gsmld_attach_gsm(tty, gsm);
2372}
2373
2374/**
2375 * gsmld_write_wakeup - asynchronous I/O notifier
2376 * @tty: tty device
2377 *
2378 * Required for the ptys, serial driver etc. since processes
2379 * that attach themselves to the master and rely on ASYNC
2380 * IO must be woken up
2381 */
2382
2383static void gsmld_write_wakeup(struct tty_struct *tty)
2384{
2385 struct gsm_mux *gsm = tty->disc_data;
2386 unsigned long flags;
2387
2388 /* Queue poll */
2389 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2390 spin_lock_irqsave(&gsm->tx_lock, flags);
2391 gsm_data_kick(gsm);
2392 if (gsm->tx_bytes < TX_THRESH_LO) {
2393 gsm_dlci_data_sweep(gsm);
2394 }
2395 spin_unlock_irqrestore(&gsm->tx_lock, flags);
2396}
2397
2398/**
2399 * gsmld_read - read function for tty
2400 * @tty: tty device
2401 * @file: file object
2402 * @buf: userspace buffer pointer
2403 * @nr: size of I/O
2404 *
2405 * Perform reads for the line discipline. We are guaranteed that the
2406 * line discipline will not be closed under us but we may get multiple
2407 * parallel readers and must handle this ourselves. We may also get
2408 * a hangup. Always called in user context, may sleep.
2409 *
2410 * This code must be sure never to sleep through a hangup.
2411 */
2412
2413static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
2414 unsigned char __user *buf, size_t nr)
2415{
2416 return -EOPNOTSUPP;
2417}
2418
2419/**
2420 * gsmld_write - write function for tty
2421 * @tty: tty device
2422 * @file: file object
2423 * @buf: userspace buffer pointer
2424 * @nr: size of I/O
2425 *
2426 * Called when the owner of the device wants to send a frame
2427 * itself (or some other control data). The data is transferred
2428 * as-is and must be properly framed and checksummed as appropriate
2429 * by userspace. Frames are either sent whole or not at all as this
2430 * avoids pain user side.
2431 */
2432
2433static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
2434 const unsigned char *buf, size_t nr)
2435{
2436 int space = tty_write_room(tty);
2437 if (space >= nr)
2438 return tty->ops->write(tty, buf, nr);
2439 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
2440 return -ENOBUFS;
2441}
2442
2443/**
2444 * gsmld_poll - poll method for N_GSM0710
2445 * @tty: terminal device
2446 * @file: file accessing it
2447 * @wait: poll table
2448 *
2449 * Called when the line discipline is asked to poll() for data or
2450 * for special events. This code is not serialized with respect to
2451 * other events save open/close.
2452 *
2453 * This code must be sure never to sleep through a hangup.
2454 * Called without the kernel lock held - fine
2455 */
2456
2457static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file,
2458 poll_table *wait)
2459{
2460 unsigned int mask = 0;
2461 struct gsm_mux *gsm = tty->disc_data;
2462
2463 poll_wait(file, &tty->read_wait, wait);
2464 poll_wait(file, &tty->write_wait, wait);
2465 if (tty_hung_up_p(file))
2466 mask |= POLLHUP;
2467 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
2468 mask |= POLLOUT | POLLWRNORM;
2469 if (gsm->dead)
2470 mask |= POLLHUP;
2471 return mask;
2472}
2473
2474static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
2475 struct gsm_config *c)
2476{
2477 int need_close = 0;
2478 int need_restart = 0;
2479
2480 /* Stuff we don't support yet - UI or I frame transport, windowing */
2481 if ((c->adaption != 1 && c->adaption != 2) || c->k)
2482 return -EOPNOTSUPP;
2483 /* Check the MRU/MTU range looks sane */
2484 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
2485 return -EINVAL;
2486 if (c->n2 < 3)
2487 return -EINVAL;
2488 if (c->encapsulation > 1) /* Basic, advanced, no I */
2489 return -EINVAL;
2490 if (c->initiator > 1)
2491 return -EINVAL;
2492 if (c->i == 0 || c->i > 2) /* UIH and UI only */
2493 return -EINVAL;
2494 /*
2495 * See what is needed for reconfiguration
2496 */
2497
2498 /* Timing fields */
2499 if (c->t1 != 0 && c->t1 != gsm->t1)
2500 need_restart = 1;
2501 if (c->t2 != 0 && c->t2 != gsm->t2)
2502 need_restart = 1;
2503 if (c->encapsulation != gsm->encoding)
2504 need_restart = 1;
2505 if (c->adaption != gsm->adaption)
2506 need_restart = 1;
2507 /* Requires care */
2508 if (c->initiator != gsm->initiator)
2509 need_close = 1;
2510 if (c->mru != gsm->mru)
2511 need_restart = 1;
2512 if (c->mtu != gsm->mtu)
2513 need_restart = 1;
2514
2515 /*
2516 * Close down what is needed, restart and initiate the new
2517 * configuration
2518 */
2519
2520 if (need_close || need_restart) {
2521 gsm_dlci_begin_close(gsm->dlci[0]);
2522 /* This will timeout if the link is down due to N2 expiring */
2523 wait_event_interruptible(gsm->event,
2524 gsm->dlci[0]->state == DLCI_CLOSED);
2525 if (signal_pending(current))
2526 return -EINTR;
2527 }
2528 if (need_restart)
2529 gsm_cleanup_mux(gsm);
2530
2531 gsm->initiator = c->initiator;
2532 gsm->mru = c->mru;
2533 gsm->mtu = c->mtu;
2534 gsm->encoding = c->encapsulation;
2535 gsm->adaption = c->adaption;
2536 gsm->n2 = c->n2;
2537
2538 if (c->i == 1)
2539 gsm->ftype = UIH;
2540 else if (c->i == 2)
2541 gsm->ftype = UI;
2542
2543 if (c->t1)
2544 gsm->t1 = c->t1;
2545 if (c->t2)
2546 gsm->t2 = c->t2;
2547
2548 /* FIXME: We need to separate activation/deactivation from adding
2549 and removing from the mux array */
2550 if (need_restart)
2551 gsm_activate_mux(gsm);
2552 if (gsm->initiator && need_close)
2553 gsm_dlci_begin_open(gsm->dlci[0]);
2554 return 0;
2555}
2556
2557static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
2558 unsigned int cmd, unsigned long arg)
2559{
2560 struct gsm_config c;
2561 struct gsm_mux *gsm = tty->disc_data;
2562
2563 switch (cmd) {
2564 case GSMIOC_GETCONF:
2565 memset(&c, 0, sizeof(c));
2566 c.adaption = gsm->adaption;
2567 c.encapsulation = gsm->encoding;
2568 c.initiator = gsm->initiator;
2569 c.t1 = gsm->t1;
2570 c.t2 = gsm->t2;
2571 c.t3 = 0; /* Not supported */
2572 c.n2 = gsm->n2;
2573 if (gsm->ftype == UIH)
2574 c.i = 1;
2575 else
2576 c.i = 2;
2577 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i);
2578 c.mru = gsm->mru;
2579 c.mtu = gsm->mtu;
2580 c.k = 0;
2581 if (copy_to_user((void *)arg, &c, sizeof(c)))
2582 return -EFAULT;
2583 return 0;
2584 case GSMIOC_SETCONF:
2585 if (copy_from_user(&c, (void *)arg, sizeof(c)))
2586 return -EFAULT;
2587 return gsmld_config(tty, gsm, &c);
2588 default:
2589 return n_tty_ioctl_helper(tty, file, cmd, arg);
2590 }
2591}
2592
2593/*
2594 * Network interface
2595 *
2596 */
2597
2598static int gsm_mux_net_open(struct net_device *net)
2599{
2600 pr_debug("%s called\n", __func__);
2601 netif_start_queue(net);
2602 return 0;
2603}
2604
2605static int gsm_mux_net_close(struct net_device *net)
2606{
2607 netif_stop_queue(net);
2608 return 0;
2609}
2610
2611static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net)
2612{
2613 return &((struct gsm_mux_net *)netdev_priv(net))->stats;
2614}
2615static void dlci_net_free(struct gsm_dlci *dlci)
2616{
2617 if (!dlci->net) {
2618 WARN_ON(1);
2619 return;
2620 }
2621 dlci->adaption = dlci->prev_adaption;
2622 dlci->data = dlci->prev_data;
2623 free_netdev(dlci->net);
2624 dlci->net = NULL;
2625}
2626static void net_free(struct kref *ref)
2627{
2628 struct gsm_mux_net *mux_net;
2629 struct gsm_dlci *dlci;
2630
2631 mux_net = container_of(ref, struct gsm_mux_net, ref);
2632 dlci = mux_net->dlci;
2633
2634 if (dlci->net) {
2635 unregister_netdev(dlci->net);
2636 dlci_net_free(dlci);
2637 }
2638}
2639
2640static inline void muxnet_get(struct gsm_mux_net *mux_net)
2641{
2642 kref_get(&mux_net->ref);
2643}
2644
2645static inline void muxnet_put(struct gsm_mux_net *mux_net)
2646{
2647 kref_put(&mux_net->ref, net_free);
2648}
2649
2650static int gsm_mux_net_start_xmit(struct sk_buff *skb,
2651 struct net_device *net)
2652{
2653 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2654 struct gsm_dlci *dlci = mux_net->dlci;
2655 muxnet_get(mux_net);
2656
2657 skb_queue_head(&dlci->skb_list, skb);
2658 STATS(net).tx_packets++;
2659 STATS(net).tx_bytes += skb->len;
2660 gsm_dlci_data_kick(dlci);
2661 /* And tell the kernel when the last transmit started. */
2662 net->trans_start = jiffies;
2663 muxnet_put(mux_net);
2664 return NETDEV_TX_OK;
2665}
2666
2667/* called when a packet did not ack after watchdogtimeout */
2668static void gsm_mux_net_tx_timeout(struct net_device *net)
2669{
2670 /* Tell syslog we are hosed. */
2671 dev_dbg(&net->dev, "Tx timed out.\n");
2672
2673 /* Update statistics */
2674 STATS(net).tx_errors++;
2675}
2676
2677static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
2678 unsigned char *in_buf, int size)
2679{
2680 struct net_device *net = dlci->net;
2681 struct sk_buff *skb;
2682 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2683 muxnet_get(mux_net);
2684
2685 /* Allocate an sk_buff */
2686 skb = dev_alloc_skb(size + NET_IP_ALIGN);
2687 if (!skb) {
2688 /* We got no receive buffer. */
2689 STATS(net).rx_dropped++;
2690 muxnet_put(mux_net);
2691 return;
2692 }
2693 skb_reserve(skb, NET_IP_ALIGN);
2694 memcpy(skb_put(skb, size), in_buf, size);
2695
2696 skb->dev = net;
2697 skb->protocol = __constant_htons(ETH_P_IP);
2698
2699 /* Ship it off to the kernel */
2700 netif_rx(skb);
2701
2702 /* update out statistics */
2703 STATS(net).rx_packets++;
2704 STATS(net).rx_bytes += size;
2705 muxnet_put(mux_net);
2706 return;
2707}
2708
2709int gsm_change_mtu(struct net_device *net, int new_mtu)
2710{
2711 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
2712 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu))
2713 return -EINVAL;
2714 net->mtu = new_mtu;
2715 return 0;
2716}
2717
2718static void gsm_mux_net_init(struct net_device *net)
2719{
2720 static const struct net_device_ops gsm_netdev_ops = {
2721 .ndo_open = gsm_mux_net_open,
2722 .ndo_stop = gsm_mux_net_close,
2723 .ndo_start_xmit = gsm_mux_net_start_xmit,
2724 .ndo_tx_timeout = gsm_mux_net_tx_timeout,
2725 .ndo_get_stats = gsm_mux_net_get_stats,
2726 .ndo_change_mtu = gsm_change_mtu,
2727 };
2728
2729 net->netdev_ops = &gsm_netdev_ops;
2730
2731 /* fill in the other fields */
2732 net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
2733 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
2734 net->type = ARPHRD_NONE;
2735 net->tx_queue_len = 10;
2736}
2737
2738
2739/* caller holds the dlci mutex */
2740static void gsm_destroy_network(struct gsm_dlci *dlci)
2741{
2742 struct gsm_mux_net *mux_net;
2743
2744 pr_debug("destroy network interface");
2745 if (!dlci->net)
2746 return;
2747 mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net);
2748 muxnet_put(mux_net);
2749}
2750
2751
2752/* caller holds the dlci mutex */
2753static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
2754{
2755 char *netname;
2756 int retval = 0;
2757 struct net_device *net;
2758 struct gsm_mux_net *mux_net;
2759
2760 if (!capable(CAP_NET_ADMIN))
2761 return -EPERM;
2762
2763 /* Already in a non tty mode */
2764 if (dlci->adaption > 2)
2765 return -EBUSY;
2766
2767 if (nc->protocol != htons(ETH_P_IP))
2768 return -EPROTONOSUPPORT;
2769
2770 if (nc->adaption != 3 && nc->adaption != 4)
2771 return -EPROTONOSUPPORT;
2772
2773 pr_debug("create network interface");
2774
2775 netname = "gsm%d";
2776 if (nc->if_name[0] != '\0')
2777 netname = nc->if_name;
2778 net = alloc_netdev(sizeof(struct gsm_mux_net),
2779 netname,
2780 gsm_mux_net_init);
2781 if (!net) {
2782 pr_err("alloc_netdev failed");
2783 return -ENOMEM;
2784 }
2785 net->mtu = dlci->gsm->mtu;
2786 mux_net = (struct gsm_mux_net *)netdev_priv(net);
2787 mux_net->dlci = dlci;
2788 kref_init(&mux_net->ref);
2789 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
2790
2791 /* reconfigure dlci for network */
2792 dlci->prev_adaption = dlci->adaption;
2793 dlci->prev_data = dlci->data;
2794 dlci->adaption = nc->adaption;
2795 dlci->data = gsm_mux_rx_netchar;
2796 dlci->net = net;
2797
2798 pr_debug("register netdev");
2799 retval = register_netdev(net);
2800 if (retval) {
2801 pr_err("network register fail %d\n", retval);
2802 dlci_net_free(dlci);
2803 return retval;
2804 }
2805 return net->ifindex; /* return network index */
2806}
2807
2808/* Line discipline for real tty */
2809struct tty_ldisc_ops tty_ldisc_packet = {
2810 .owner = THIS_MODULE,
2811 .magic = TTY_LDISC_MAGIC,
2812 .name = "n_gsm",
2813 .open = gsmld_open,
2814 .close = gsmld_close,
2815 .flush_buffer = gsmld_flush_buffer,
2816 .chars_in_buffer = gsmld_chars_in_buffer,
2817 .read = gsmld_read,
2818 .write = gsmld_write,
2819 .ioctl = gsmld_ioctl,
2820 .poll = gsmld_poll,
2821 .receive_buf = gsmld_receive_buf,
2822 .write_wakeup = gsmld_write_wakeup
2823};
2824
2825/*
2826 * Virtual tty side
2827 */
2828
2829#define TX_SIZE 512
2830
2831static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
2832{
2833 u8 modembits[5];
2834 struct gsm_control *ctrl;
2835 int len = 2;
2836
2837 if (brk)
2838 len++;
2839
2840 modembits[0] = len << 1 | EA; /* Data bytes */
2841 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */
2842 modembits[2] = gsm_encode_modem(dlci) << 1 | EA;
2843 if (brk)
2844 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */
2845 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1);
2846 if (ctrl == NULL)
2847 return -ENOMEM;
2848 return gsm_control_wait(dlci->gsm, ctrl);
2849}
2850
2851static int gsm_carrier_raised(struct tty_port *port)
2852{
2853 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2854 /* Not yet open so no carrier info */
2855 if (dlci->state != DLCI_OPEN)
2856 return 0;
2857 if (debug & 2)
2858 return 1;
2859 return dlci->modem_rx & TIOCM_CD;
2860}
2861
2862static void gsm_dtr_rts(struct tty_port *port, int onoff)
2863{
2864 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
2865 unsigned int modem_tx = dlci->modem_tx;
2866 if (onoff)
2867 modem_tx |= TIOCM_DTR | TIOCM_RTS;
2868 else
2869 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
2870 if (modem_tx != dlci->modem_tx) {
2871 dlci->modem_tx = modem_tx;
2872 gsmtty_modem_update(dlci, 0);
2873 }
2874}
2875
2876static const struct tty_port_operations gsm_port_ops = {
2877 .carrier_raised = gsm_carrier_raised,
2878 .dtr_rts = gsm_dtr_rts,
2879};
2880
2881
2882static int gsmtty_open(struct tty_struct *tty, struct file *filp)
2883{
2884 struct gsm_mux *gsm;
2885 struct gsm_dlci *dlci;
2886 struct tty_port *port;
2887 unsigned int line = tty->index;
2888 unsigned int mux = line >> 6;
2889
2890 line = line & 0x3F;
2891
2892 if (mux >= MAX_MUX)
2893 return -ENXIO;
2894 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
2895 if (gsm_mux[mux] == NULL)
2896 return -EUNATCH;
2897 if (line == 0 || line > 61) /* 62/63 reserved */
2898 return -ECHRNG;
2899 gsm = gsm_mux[mux];
2900 if (gsm->dead)
2901 return -EL2HLT;
2902 /* If DLCI 0 is not yet fully open return an error. This is ok from a locking
2903 perspective as we don't have to worry about this if DLCI0 is lost */
2904 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN)
2905 return -EL2NSYNC;
2906 dlci = gsm->dlci[line];
2907 if (dlci == NULL)
2908 dlci = gsm_dlci_alloc(gsm, line);
2909 if (dlci == NULL)
2910 return -ENOMEM;
2911 port = &dlci->port;
2912 port->count++;
2913 tty->driver_data = dlci;
2914 dlci_get(dlci);
2915 dlci_get(dlci->gsm->dlci[0]);
2916 mux_get(dlci->gsm);
2917 tty_port_tty_set(port, tty);
2918
2919 dlci->modem_rx = 0;
2920 /* We could in theory open and close before we wait - eg if we get
2921 a DM straight back. This is ok as that will have caused a hangup */
2922 set_bit(ASYNCB_INITIALIZED, &port->flags);
2923 /* Start sending off SABM messages */
2924 gsm_dlci_begin_open(dlci);
2925 /* And wait for virtual carrier */
2926 return tty_port_block_til_ready(port, tty, filp);
2927}
2928
2929static void gsmtty_close(struct tty_struct *tty, struct file *filp)
2930{
2931 struct gsm_dlci *dlci = tty->driver_data;
2932 struct gsm_mux *gsm;
2933
2934 if (dlci == NULL)
2935 return;
2936 mutex_lock(&dlci->mutex);
2937 gsm_destroy_network(dlci);
2938 mutex_unlock(&dlci->mutex);
2939 gsm = dlci->gsm;
2940 if (tty_port_close_start(&dlci->port, tty, filp) == 0)
2941 goto out;
2942 gsm_dlci_begin_close(dlci);
2943 tty_port_close_end(&dlci->port, tty);
2944 tty_port_tty_set(&dlci->port, NULL);
2945out:
2946 dlci_put(dlci);
2947 dlci_put(gsm->dlci[0]);
2948 mux_put(gsm);
2949}
2950
2951static void gsmtty_hangup(struct tty_struct *tty)
2952{
2953 struct gsm_dlci *dlci = tty->driver_data;
2954 tty_port_hangup(&dlci->port);
2955 gsm_dlci_begin_close(dlci);
2956}
2957
2958static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
2959 int len)
2960{
2961 struct gsm_dlci *dlci = tty->driver_data;
2962 /* Stuff the bytes into the fifo queue */
2963 int sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock);
2964 /* Need to kick the channel */
2965 gsm_dlci_data_kick(dlci);
2966 return sent;
2967}
2968
2969static int gsmtty_write_room(struct tty_struct *tty)
2970{
2971 struct gsm_dlci *dlci = tty->driver_data;
2972 return TX_SIZE - kfifo_len(dlci->fifo);
2973}
2974
2975static int gsmtty_chars_in_buffer(struct tty_struct *tty)
2976{
2977 struct gsm_dlci *dlci = tty->driver_data;
2978 return kfifo_len(dlci->fifo);
2979}
2980
2981static void gsmtty_flush_buffer(struct tty_struct *tty)
2982{
2983 struct gsm_dlci *dlci = tty->driver_data;
2984 /* Caution needed: If we implement reliable transport classes
2985 then the data being transmitted can't simply be junked once
2986 it has first hit the stack. Until then we can just blow it
2987 away */
2988 kfifo_reset(dlci->fifo);
2989 /* Need to unhook this DLCI from the transmit queue logic */
2990}
2991
2992static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
2993{
2994 /* The FIFO handles the queue so the kernel will do the right
2995 thing waiting on chars_in_buffer before calling us. No work
2996 to do here */
2997}
2998
2999static int gsmtty_tiocmget(struct tty_struct *tty)
3000{
3001 struct gsm_dlci *dlci = tty->driver_data;
3002 return dlci->modem_rx;
3003}
3004
3005static int gsmtty_tiocmset(struct tty_struct *tty,
3006 unsigned int set, unsigned int clear)
3007{
3008 struct gsm_dlci *dlci = tty->driver_data;
3009 unsigned int modem_tx = dlci->modem_tx;
3010
3011 modem_tx &= ~clear;
3012 modem_tx |= set;
3013
3014 if (modem_tx != dlci->modem_tx) {
3015 dlci->modem_tx = modem_tx;
3016 return gsmtty_modem_update(dlci, 0);
3017 }
3018 return 0;
3019}
3020
3021
3022static int gsmtty_ioctl(struct tty_struct *tty,
3023 unsigned int cmd, unsigned long arg)
3024{
3025 struct gsm_dlci *dlci = tty->driver_data;
3026 struct gsm_netconfig nc;
3027 int index;
3028
3029 switch (cmd) {
3030 case GSMIOC_ENABLE_NET:
3031 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
3032 return -EFAULT;
3033 nc.if_name[IFNAMSIZ-1] = '\0';
3034 /* return net interface index or error code */
3035 mutex_lock(&dlci->mutex);
3036 index = gsm_create_network(dlci, &nc);
3037 mutex_unlock(&dlci->mutex);
3038 if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
3039 return -EFAULT;
3040 return index;
3041 case GSMIOC_DISABLE_NET:
3042 if (!capable(CAP_NET_ADMIN))
3043 return -EPERM;
3044 mutex_lock(&dlci->mutex);
3045 gsm_destroy_network(dlci);
3046 mutex_unlock(&dlci->mutex);
3047 return 0;
3048 default:
3049 return -ENOIOCTLCMD;
3050 }
3051}
3052
3053static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
3054{
3055 /* For the moment its fixed. In actual fact the speed information
3056 for the virtual channel can be propogated in both directions by
3057 the RPN control message. This however rapidly gets nasty as we
3058 then have to remap modem signals each way according to whether
3059 our virtual cable is null modem etc .. */
3060 tty_termios_copy_hw(tty->termios, old);
3061}
3062
3063static void gsmtty_throttle(struct tty_struct *tty)
3064{
3065 struct gsm_dlci *dlci = tty->driver_data;
3066 if (tty->termios->c_cflag & CRTSCTS)
3067 dlci->modem_tx &= ~TIOCM_DTR;
3068 dlci->throttled = 1;
3069 /* Send an MSC with DTR cleared */
3070 gsmtty_modem_update(dlci, 0);
3071}
3072
3073static void gsmtty_unthrottle(struct tty_struct *tty)
3074{
3075 struct gsm_dlci *dlci = tty->driver_data;
3076 if (tty->termios->c_cflag & CRTSCTS)
3077 dlci->modem_tx |= TIOCM_DTR;
3078 dlci->throttled = 0;
3079 /* Send an MSC with DTR set */
3080 gsmtty_modem_update(dlci, 0);
3081}
3082
3083static int gsmtty_break_ctl(struct tty_struct *tty, int state)
3084{
3085 struct gsm_dlci *dlci = tty->driver_data;
3086 int encode = 0; /* Off */
3087
3088 if (state == -1) /* "On indefinitely" - we can't encode this
3089 properly */
3090 encode = 0x0F;
3091 else if (state > 0) {
3092 encode = state / 200; /* mS to encoding */
3093 if (encode > 0x0F)
3094 encode = 0x0F; /* Best effort */
3095 }
3096 return gsmtty_modem_update(dlci, encode);
3097}
3098
3099
3100/* Virtual ttys for the demux */
3101static const struct tty_operations gsmtty_ops = {
3102 .open = gsmtty_open,
3103 .close = gsmtty_close,
3104 .write = gsmtty_write,
3105 .write_room = gsmtty_write_room,
3106 .chars_in_buffer = gsmtty_chars_in_buffer,
3107 .flush_buffer = gsmtty_flush_buffer,
3108 .ioctl = gsmtty_ioctl,
3109 .throttle = gsmtty_throttle,
3110 .unthrottle = gsmtty_unthrottle,
3111 .set_termios = gsmtty_set_termios,
3112 .hangup = gsmtty_hangup,
3113 .wait_until_sent = gsmtty_wait_until_sent,
3114 .tiocmget = gsmtty_tiocmget,
3115 .tiocmset = gsmtty_tiocmset,
3116 .break_ctl = gsmtty_break_ctl,
3117};
3118
3119
3120
3121static int __init gsm_init(void)
3122{
3123 /* Fill in our line protocol discipline, and register it */
3124 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
3125 if (status != 0) {
3126 pr_err("n_gsm: can't register line discipline (err = %d)\n",
3127 status);
3128 return status;
3129 }
3130
3131 gsm_tty_driver = alloc_tty_driver(256);
3132 if (!gsm_tty_driver) {
3133 tty_unregister_ldisc(N_GSM0710);
3134 pr_err("gsm_init: tty allocation failed.\n");
3135 return -EINVAL;
3136 }
3137 gsm_tty_driver->driver_name = "gsmtty";
3138 gsm_tty_driver->name = "gsmtty";
3139 gsm_tty_driver->major = 0; /* Dynamic */
3140 gsm_tty_driver->minor_start = 0;
3141 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
3142 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
3143 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
3144 | TTY_DRIVER_HARDWARE_BREAK;
3145 gsm_tty_driver->init_termios = tty_std_termios;
3146 /* Fixme */
3147 gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
3148 tty_set_operations(gsm_tty_driver, &gsmtty_ops);
3149
3150 spin_lock_init(&gsm_mux_lock);
3151
3152 if (tty_register_driver(gsm_tty_driver)) {
3153 put_tty_driver(gsm_tty_driver);
3154 tty_unregister_ldisc(N_GSM0710);
3155 pr_err("gsm_init: tty registration failed.\n");
3156 return -EBUSY;
3157 }
3158 pr_debug("gsm_init: loaded as %d,%d.\n",
3159 gsm_tty_driver->major, gsm_tty_driver->minor_start);
3160 return 0;
3161}
3162
3163static void __exit gsm_exit(void)
3164{
3165 int status = tty_unregister_ldisc(N_GSM0710);
3166 if (status != 0)
3167 pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
3168 status);
3169 tty_unregister_driver(gsm_tty_driver);
3170 put_tty_driver(gsm_tty_driver);
3171}
3172
3173module_init(gsm_init);
3174module_exit(gsm_exit);
3175
3176
3177MODULE_LICENSE("GPL");
3178MODULE_ALIAS_LDISC(N_GSM0710);