1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * n_gsm.c GSM 0710 tty multiplexor 4 * Copyright (c) 2009/10 Intel Corporation 5 * 6 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE * 7 * 8 * TO DO: 9 * Mostly done: ioctls for setting modes/timing 10 * Partly done: hooks so you can pull off frames to non tty devs 11 * Restart DLCI 0 when it closes ? 12 * Improve the tx engine 13 * Resolve tx side locking by adding a queue_head and routing 14 * all control traffic via it 15 * General tidy/document 16 * Review the locking/move to refcounts more (mux now moved to an 17 * alloc/free model ready) 18 * Use newest tty open/close port helpers and install hooks 19 * What to do about power functions ? 20 * Termios setting and negotiation 21 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets 22 * 23 */ 24 25 #include <linux/types.h> 26 #include <linux/major.h> 27 #include <linux/errno.h> 28 #include <linux/signal.h> 29 #include <linux/fcntl.h> 30 #include <linux/sched/signal.h> 31 #include <linux/interrupt.h> 32 #include <linux/tty.h> 33 #include <linux/ctype.h> 34 #include <linux/mm.h> 35 #include <linux/string.h> 36 #include <linux/slab.h> 37 #include <linux/poll.h> 38 #include <linux/bitops.h> 39 #include <linux/file.h> 40 #include <linux/uaccess.h> 41 #include <linux/module.h> 42 #include <linux/timer.h> 43 #include <linux/tty_flip.h> 44 #include <linux/tty_driver.h> 45 #include <linux/serial.h> 46 #include <linux/kfifo.h> 47 #include <linux/skbuff.h> 48 #include <net/arp.h> 49 #include <linux/ip.h> 50 #include <linux/netdevice.h> 51 #include <linux/etherdevice.h> 52 #include <linux/gsmmux.h> 53 54 static int debug; 55 module_param(debug, int, 0600); 56 57 /* Defaults: these are from the specification */ 58 59 #define T1 10 /* 100mS */ 60 #define T2 34 /* 333mS */ 61 #define N2 3 /* Retry 3 times */ 62 63 /* Use long timers for testing at low speed with debug on */ 64 #ifdef DEBUG_TIMING 65 #define T1 100 66 #define T2 200 67 #endif 68 69 /* 70 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte 71 * limits so this is plenty 72 */ 73 #define MAX_MRU 1500 74 #define MAX_MTU 1500 75 #define GSM_NET_TX_TIMEOUT (HZ*10) 76 77 /** 78 * struct gsm_mux_net - network interface 79 * @struct gsm_dlci* dlci 80 * 81 * Created when net interface is initialized. 82 **/ 83 struct gsm_mux_net { 84 struct kref ref; 85 struct gsm_dlci *dlci; 86 }; 87 88 /* 89 * Each block of data we have queued to go out is in the form of 90 * a gsm_msg which holds everything we need in a link layer independent 91 * format 92 */ 93 94 struct gsm_msg { 95 struct list_head list; 96 u8 addr; /* DLCI address + flags */ 97 u8 ctrl; /* Control byte + flags */ 98 unsigned int len; /* Length of data block (can be zero) */ 99 unsigned char *data; /* Points into buffer but not at the start */ 100 unsigned char buffer[0]; 101 }; 102 103 /* 104 * Each active data link has a gsm_dlci structure associated which ties 105 * the link layer to an optional tty (if the tty side is open). To avoid 106 * complexity right now these are only ever freed up when the mux is 107 * shut down. 108 * 109 * At the moment we don't free DLCI objects until the mux is torn down 110 * this avoid object life time issues but might be worth review later. 111 */ 112 113 struct gsm_dlci { 114 struct gsm_mux *gsm; 115 int addr; 116 int state; 117 #define DLCI_CLOSED 0 118 #define DLCI_OPENING 1 /* Sending SABM not seen UA */ 119 #define DLCI_OPEN 2 /* SABM/UA complete */ 120 #define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */ 121 struct mutex mutex; 122 123 /* Link layer */ 124 spinlock_t lock; /* Protects the internal state */ 125 struct timer_list t1; /* Retransmit timer for SABM and UA */ 126 int retries; 127 /* Uplink tty if active */ 128 struct tty_port port; /* The tty bound to this DLCI if there is one */ 129 struct kfifo *fifo; /* Queue fifo for the DLCI */ 130 struct kfifo _fifo; /* For new fifo API porting only */ 131 int adaption; /* Adaption layer in use */ 132 int prev_adaption; 133 u32 modem_rx; /* Our incoming virtual modem lines */ 134 u32 modem_tx; /* Our outgoing modem lines */ 135 int dead; /* Refuse re-open */ 136 /* Flow control */ 137 int throttled; /* Private copy of throttle state */ 138 int constipated; /* Throttle status for outgoing */ 139 /* Packetised I/O */ 140 struct sk_buff *skb; /* Frame being sent */ 141 struct sk_buff_head skb_list; /* Queued frames */ 142 /* Data handling callback */ 143 void (*data)(struct gsm_dlci *dlci, u8 *data, int len); 144 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len); 145 struct net_device *net; /* network interface, if created */ 146 }; 147 148 /* DLCI 0, 62/63 are special or reserved see gsmtty_open */ 149 150 #define NUM_DLCI 64 151 152 /* 153 * DLCI 0 is used to pass control blocks out of band of the data 154 * flow (and with a higher link priority). One command can be outstanding 155 * at a time and we use this structure to manage them. They are created 156 * and destroyed by the user context, and updated by the receive paths 157 * and timers 158 */ 159 160 struct gsm_control { 161 u8 cmd; /* Command we are issuing */ 162 u8 *data; /* Data for the command in case we retransmit */ 163 int len; /* Length of block for retransmission */ 164 int done; /* Done flag */ 165 int error; /* Error if any */ 166 }; 167 168 /* 169 * Each GSM mux we have is represented by this structure. If we are 170 * operating as an ldisc then we use this structure as our ldisc 171 * state. We need to sort out lifetimes and locking with respect 172 * to the gsm mux array. For now we don't free DLCI objects that 173 * have been instantiated until the mux itself is terminated. 174 * 175 * To consider further: tty open versus mux shutdown. 176 */ 177 178 struct gsm_mux { 179 struct tty_struct *tty; /* The tty our ldisc is bound to */ 180 spinlock_t lock; 181 struct mutex mutex; 182 unsigned int num; 183 struct kref ref; 184 185 /* Events on the GSM channel */ 186 wait_queue_head_t event; 187 188 /* Bits for GSM mode decoding */ 189 190 /* Framing Layer */ 191 unsigned char *buf; 192 int state; 193 #define GSM_SEARCH 0 194 #define GSM_START 1 195 #define GSM_ADDRESS 2 196 #define GSM_CONTROL 3 197 #define GSM_LEN 4 198 #define GSM_DATA 5 199 #define GSM_FCS 6 200 #define GSM_OVERRUN 7 201 #define GSM_LEN0 8 202 #define GSM_LEN1 9 203 #define GSM_SSOF 10 204 unsigned int len; 205 unsigned int address; 206 unsigned int count; 207 int escape; 208 int encoding; 209 u8 control; 210 u8 fcs; 211 u8 received_fcs; 212 u8 *txframe; /* TX framing buffer */ 213 214 /* Methods for the receiver side */ 215 void (*receive)(struct gsm_mux *gsm, u8 ch); 216 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag); 217 /* And transmit side */ 218 int (*output)(struct gsm_mux *mux, u8 *data, int len); 219 220 /* Link Layer */ 221 unsigned int mru; 222 unsigned int mtu; 223 int initiator; /* Did we initiate connection */ 224 int dead; /* Has the mux been shut down */ 225 struct gsm_dlci *dlci[NUM_DLCI]; 226 int constipated; /* Asked by remote to shut up */ 227 228 spinlock_t tx_lock; 229 unsigned int tx_bytes; /* TX data outstanding */ 230 #define TX_THRESH_HI 8192 231 #define TX_THRESH_LO 2048 232 struct list_head tx_list; /* Pending data packets */ 233 234 /* Control messages */ 235 struct timer_list t2_timer; /* Retransmit timer for commands */ 236 int cretries; /* Command retry counter */ 237 struct gsm_control *pending_cmd;/* Our current pending command */ 238 spinlock_t control_lock; /* Protects the pending command */ 239 240 /* Configuration */ 241 int adaption; /* 1 or 2 supported */ 242 u8 ftype; /* UI or UIH */ 243 int t1, t2; /* Timers in 1/100th of a sec */ 244 int n2; /* Retry count */ 245 246 /* Statistics (not currently exposed) */ 247 unsigned long bad_fcs; 248 unsigned long malformed; 249 unsigned long io_error; 250 unsigned long bad_size; 251 unsigned long unsupported; 252 }; 253 254 255 /* 256 * Mux objects - needed so that we can translate a tty index into the 257 * relevant mux and DLCI. 258 */ 259 260 #define MAX_MUX 4 /* 256 minors */ 261 static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */ 262 static spinlock_t gsm_mux_lock; 263 264 static struct tty_driver *gsm_tty_driver; 265 266 /* 267 * This section of the driver logic implements the GSM encodings 268 * both the basic and the 'advanced'. Reliable transport is not 269 * supported. 270 */ 271 272 #define CR 0x02 273 #define EA 0x01 274 #define PF 0x10 275 276 /* I is special: the rest are ..*/ 277 #define RR 0x01 278 #define UI 0x03 279 #define RNR 0x05 280 #define REJ 0x09 281 #define DM 0x0F 282 #define SABM 0x2F 283 #define DISC 0x43 284 #define UA 0x63 285 #define UIH 0xEF 286 287 /* Channel commands */ 288 #define CMD_NSC 0x09 289 #define CMD_TEST 0x11 290 #define CMD_PSC 0x21 291 #define CMD_RLS 0x29 292 #define CMD_FCOFF 0x31 293 #define CMD_PN 0x41 294 #define CMD_RPN 0x49 295 #define CMD_FCON 0x51 296 #define CMD_CLD 0x61 297 #define CMD_SNC 0x69 298 #define CMD_MSC 0x71 299 300 /* Virtual modem bits */ 301 #define MDM_FC 0x01 302 #define MDM_RTC 0x02 303 #define MDM_RTR 0x04 304 #define MDM_IC 0x20 305 #define MDM_DV 0x40 306 307 #define GSM0_SOF 0xF9 308 #define GSM1_SOF 0x7E 309 #define GSM1_ESCAPE 0x7D 310 #define GSM1_ESCAPE_BITS 0x20 311 #define XON 0x11 312 #define XOFF 0x13 313 314 static const struct tty_port_operations gsm_port_ops; 315 316 /* 317 * CRC table for GSM 0710 318 */ 319 320 static const u8 gsm_fcs8[256] = { 321 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75, 322 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B, 323 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69, 324 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67, 325 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D, 326 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43, 327 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51, 328 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F, 329 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05, 330 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B, 331 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19, 332 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17, 333 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D, 334 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33, 335 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21, 336 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F, 337 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95, 338 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B, 339 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89, 340 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87, 341 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD, 342 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3, 343 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1, 344 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF, 345 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5, 346 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB, 347 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9, 348 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7, 349 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD, 350 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3, 351 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1, 352 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF 353 }; 354 355 #define INIT_FCS 0xFF 356 #define GOOD_FCS 0xCF 357 358 /** 359 * gsm_fcs_add - update FCS 360 * @fcs: Current FCS 361 * @c: Next data 362 * 363 * Update the FCS to include c. Uses the algorithm in the specification 364 * notes. 365 */ 366 367 static inline u8 gsm_fcs_add(u8 fcs, u8 c) 368 { 369 return gsm_fcs8[fcs ^ c]; 370 } 371 372 /** 373 * gsm_fcs_add_block - update FCS for a block 374 * @fcs: Current FCS 375 * @c: buffer of data 376 * @len: length of buffer 377 * 378 * Update the FCS to include c. Uses the algorithm in the specification 379 * notes. 380 */ 381 382 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len) 383 { 384 while (len--) 385 fcs = gsm_fcs8[fcs ^ *c++]; 386 return fcs; 387 } 388 389 /** 390 * gsm_read_ea - read a byte into an EA 391 * @val: variable holding value 392 * c: byte going into the EA 393 * 394 * Processes one byte of an EA. Updates the passed variable 395 * and returns 1 if the EA is now completely read 396 */ 397 398 static int gsm_read_ea(unsigned int *val, u8 c) 399 { 400 /* Add the next 7 bits into the value */ 401 *val <<= 7; 402 *val |= c >> 1; 403 /* Was this the last byte of the EA 1 = yes*/ 404 return c & EA; 405 } 406 407 /** 408 * gsm_encode_modem - encode modem data bits 409 * @dlci: DLCI to encode from 410 * 411 * Returns the correct GSM encoded modem status bits (6 bit field) for 412 * the current status of the DLCI and attached tty object 413 */ 414 415 static u8 gsm_encode_modem(const struct gsm_dlci *dlci) 416 { 417 u8 modembits = 0; 418 /* FC is true flow control not modem bits */ 419 if (dlci->throttled) 420 modembits |= MDM_FC; 421 if (dlci->modem_tx & TIOCM_DTR) 422 modembits |= MDM_RTC; 423 if (dlci->modem_tx & TIOCM_RTS) 424 modembits |= MDM_RTR; 425 if (dlci->modem_tx & TIOCM_RI) 426 modembits |= MDM_IC; 427 if (dlci->modem_tx & TIOCM_CD) 428 modembits |= MDM_DV; 429 return modembits; 430 } 431 432 /** 433 * gsm_print_packet - display a frame for debug 434 * @hdr: header to print before decode 435 * @addr: address EA from the frame 436 * @cr: C/R bit from the frame 437 * @control: control including PF bit 438 * @data: following data bytes 439 * @dlen: length of data 440 * 441 * Displays a packet in human readable format for debugging purposes. The 442 * style is based on amateur radio LAP-B dump display. 443 */ 444 445 static void gsm_print_packet(const char *hdr, int addr, int cr, 446 u8 control, const u8 *data, int dlen) 447 { 448 if (!(debug & 1)) 449 return; 450 451 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]); 452 453 switch (control & ~PF) { 454 case SABM: 455 pr_cont("SABM"); 456 break; 457 case UA: 458 pr_cont("UA"); 459 break; 460 case DISC: 461 pr_cont("DISC"); 462 break; 463 case DM: 464 pr_cont("DM"); 465 break; 466 case UI: 467 pr_cont("UI"); 468 break; 469 case UIH: 470 pr_cont("UIH"); 471 break; 472 default: 473 if (!(control & 0x01)) { 474 pr_cont("I N(S)%d N(R)%d", 475 (control & 0x0E) >> 1, (control & 0xE0) >> 5); 476 } else switch (control & 0x0F) { 477 case RR: 478 pr_cont("RR(%d)", (control & 0xE0) >> 5); 479 break; 480 case RNR: 481 pr_cont("RNR(%d)", (control & 0xE0) >> 5); 482 break; 483 case REJ: 484 pr_cont("REJ(%d)", (control & 0xE0) >> 5); 485 break; 486 default: 487 pr_cont("[%02X]", control); 488 } 489 } 490 491 if (control & PF) 492 pr_cont("(P)"); 493 else 494 pr_cont("(F)"); 495 496 if (dlen) { 497 int ct = 0; 498 while (dlen--) { 499 if (ct % 8 == 0) { 500 pr_cont("\n"); 501 pr_debug(" "); 502 } 503 pr_cont("%02X ", *data++); 504 ct++; 505 } 506 } 507 pr_cont("\n"); 508 } 509 510 511 /* 512 * Link level transmission side 513 */ 514 515 /** 516 * gsm_stuff_packet - bytestuff a packet 517 * @ibuf: input 518 * @obuf: output 519 * @len: length of input 520 * 521 * Expand a buffer by bytestuffing it. The worst case size change 522 * is doubling and the caller is responsible for handing out 523 * suitable sized buffers. 524 */ 525 526 static int gsm_stuff_frame(const u8 *input, u8 *output, int len) 527 { 528 int olen = 0; 529 while (len--) { 530 if (*input == GSM1_SOF || *input == GSM1_ESCAPE 531 || *input == XON || *input == XOFF) { 532 *output++ = GSM1_ESCAPE; 533 *output++ = *input++ ^ GSM1_ESCAPE_BITS; 534 olen++; 535 } else 536 *output++ = *input++; 537 olen++; 538 } 539 return olen; 540 } 541 542 /** 543 * gsm_send - send a control frame 544 * @gsm: our GSM mux 545 * @addr: address for control frame 546 * @cr: command/response bit 547 * @control: control byte including PF bit 548 * 549 * Format up and transmit a control frame. These do not go via the 550 * queueing logic as they should be transmitted ahead of data when 551 * they are needed. 552 * 553 * FIXME: Lock versus data TX path 554 */ 555 556 static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control) 557 { 558 int len; 559 u8 cbuf[10]; 560 u8 ibuf[3]; 561 562 switch (gsm->encoding) { 563 case 0: 564 cbuf[0] = GSM0_SOF; 565 cbuf[1] = (addr << 2) | (cr << 1) | EA; 566 cbuf[2] = control; 567 cbuf[3] = EA; /* Length of data = 0 */ 568 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3); 569 cbuf[5] = GSM0_SOF; 570 len = 6; 571 break; 572 case 1: 573 case 2: 574 /* Control frame + packing (but not frame stuffing) in mode 1 */ 575 ibuf[0] = (addr << 2) | (cr << 1) | EA; 576 ibuf[1] = control; 577 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2); 578 /* Stuffing may double the size worst case */ 579 len = gsm_stuff_frame(ibuf, cbuf + 1, 3); 580 /* Now add the SOF markers */ 581 cbuf[0] = GSM1_SOF; 582 cbuf[len + 1] = GSM1_SOF; 583 /* FIXME: we can omit the lead one in many cases */ 584 len += 2; 585 break; 586 default: 587 WARN_ON(1); 588 return; 589 } 590 gsm->output(gsm, cbuf, len); 591 gsm_print_packet("-->", addr, cr, control, NULL, 0); 592 } 593 594 /** 595 * gsm_response - send a control response 596 * @gsm: our GSM mux 597 * @addr: address for control frame 598 * @control: control byte including PF bit 599 * 600 * Format up and transmit a link level response frame. 601 */ 602 603 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control) 604 { 605 gsm_send(gsm, addr, 0, control); 606 } 607 608 /** 609 * gsm_command - send a control command 610 * @gsm: our GSM mux 611 * @addr: address for control frame 612 * @control: control byte including PF bit 613 * 614 * Format up and transmit a link level command frame. 615 */ 616 617 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control) 618 { 619 gsm_send(gsm, addr, 1, control); 620 } 621 622 /* Data transmission */ 623 624 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */ 625 626 /** 627 * gsm_data_alloc - allocate data frame 628 * @gsm: GSM mux 629 * @addr: DLCI address 630 * @len: length excluding header and FCS 631 * @ctrl: control byte 632 * 633 * Allocate a new data buffer for sending frames with data. Space is left 634 * at the front for header bytes but that is treated as an implementation 635 * detail and not for the high level code to use 636 */ 637 638 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len, 639 u8 ctrl) 640 { 641 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN, 642 GFP_ATOMIC); 643 if (m == NULL) 644 return NULL; 645 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */ 646 m->len = len; 647 m->addr = addr; 648 m->ctrl = ctrl; 649 INIT_LIST_HEAD(&m->list); 650 return m; 651 } 652 653 /** 654 * gsm_data_kick - poke the queue 655 * @gsm: GSM Mux 656 * 657 * The tty device has called us to indicate that room has appeared in 658 * the transmit queue. Ram more data into the pipe if we have any 659 * If we have been flow-stopped by a CMD_FCOFF, then we can only 660 * send messages on DLCI0 until CMD_FCON 661 * 662 * FIXME: lock against link layer control transmissions 663 */ 664 665 static void gsm_data_kick(struct gsm_mux *gsm) 666 { 667 struct gsm_msg *msg, *nmsg; 668 int len; 669 int skip_sof = 0; 670 671 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) { 672 if (gsm->constipated && msg->addr) 673 continue; 674 if (gsm->encoding != 0) { 675 gsm->txframe[0] = GSM1_SOF; 676 len = gsm_stuff_frame(msg->data, 677 gsm->txframe + 1, msg->len); 678 gsm->txframe[len + 1] = GSM1_SOF; 679 len += 2; 680 } else { 681 gsm->txframe[0] = GSM0_SOF; 682 memcpy(gsm->txframe + 1 , msg->data, msg->len); 683 gsm->txframe[msg->len + 1] = GSM0_SOF; 684 len = msg->len + 2; 685 } 686 687 if (debug & 4) 688 print_hex_dump_bytes("gsm_data_kick: ", 689 DUMP_PREFIX_OFFSET, 690 gsm->txframe, len); 691 692 if (gsm->output(gsm, gsm->txframe + skip_sof, 693 len - skip_sof) < 0) 694 break; 695 /* FIXME: Can eliminate one SOF in many more cases */ 696 gsm->tx_bytes -= msg->len; 697 /* For a burst of frames skip the extra SOF within the 698 burst */ 699 skip_sof = 1; 700 701 list_del(&msg->list); 702 kfree(msg); 703 } 704 } 705 706 /** 707 * __gsm_data_queue - queue a UI or UIH frame 708 * @dlci: DLCI sending the data 709 * @msg: message queued 710 * 711 * Add data to the transmit queue and try and get stuff moving 712 * out of the mux tty if not already doing so. The Caller must hold 713 * the gsm tx lock. 714 */ 715 716 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) 717 { 718 struct gsm_mux *gsm = dlci->gsm; 719 u8 *dp = msg->data; 720 u8 *fcs = dp + msg->len; 721 722 /* Fill in the header */ 723 if (gsm->encoding == 0) { 724 if (msg->len < 128) 725 *--dp = (msg->len << 1) | EA; 726 else { 727 *--dp = (msg->len >> 7); /* bits 7 - 15 */ 728 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */ 729 } 730 } 731 732 *--dp = msg->ctrl; 733 if (gsm->initiator) 734 *--dp = (msg->addr << 2) | 2 | EA; 735 else 736 *--dp = (msg->addr << 2) | EA; 737 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp); 738 /* Ugly protocol layering violation */ 739 if (msg->ctrl == UI || msg->ctrl == (UI|PF)) 740 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len); 741 *fcs = 0xFF - *fcs; 742 743 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl, 744 msg->data, msg->len); 745 746 /* Move the header back and adjust the length, also allow for the FCS 747 now tacked on the end */ 748 msg->len += (msg->data - dp) + 1; 749 msg->data = dp; 750 751 /* Add to the actual output queue */ 752 list_add_tail(&msg->list, &gsm->tx_list); 753 gsm->tx_bytes += msg->len; 754 gsm_data_kick(gsm); 755 } 756 757 /** 758 * gsm_data_queue - queue a UI or UIH frame 759 * @dlci: DLCI sending the data 760 * @msg: message queued 761 * 762 * Add data to the transmit queue and try and get stuff moving 763 * out of the mux tty if not already doing so. Take the 764 * the gsm tx lock and dlci lock. 765 */ 766 767 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) 768 { 769 unsigned long flags; 770 spin_lock_irqsave(&dlci->gsm->tx_lock, flags); 771 __gsm_data_queue(dlci, msg); 772 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); 773 } 774 775 /** 776 * gsm_dlci_data_output - try and push data out of a DLCI 777 * @gsm: mux 778 * @dlci: the DLCI to pull data from 779 * 780 * Pull data from a DLCI and send it into the transmit queue if there 781 * is data. Keep to the MRU of the mux. This path handles the usual tty 782 * interface which is a byte stream with optional modem data. 783 * 784 * Caller must hold the tx_lock of the mux. 785 */ 786 787 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci) 788 { 789 struct gsm_msg *msg; 790 u8 *dp; 791 int len, total_size, size; 792 int h = dlci->adaption - 1; 793 794 total_size = 0; 795 while (1) { 796 len = kfifo_len(dlci->fifo); 797 if (len == 0) 798 return total_size; 799 800 /* MTU/MRU count only the data bits */ 801 if (len > gsm->mtu) 802 len = gsm->mtu; 803 804 size = len + h; 805 806 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); 807 /* FIXME: need a timer or something to kick this so it can't 808 get stuck with no work outstanding and no buffer free */ 809 if (msg == NULL) 810 return -ENOMEM; 811 dp = msg->data; 812 switch (dlci->adaption) { 813 case 1: /* Unstructured */ 814 break; 815 case 2: /* Unstructed with modem bits. 816 Always one byte as we never send inline break data */ 817 *dp++ = gsm_encode_modem(dlci); 818 break; 819 } 820 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len); 821 __gsm_data_queue(dlci, msg); 822 total_size += size; 823 } 824 /* Bytes of data we used up */ 825 return total_size; 826 } 827 828 /** 829 * gsm_dlci_data_output_framed - try and push data out of a DLCI 830 * @gsm: mux 831 * @dlci: the DLCI to pull data from 832 * 833 * Pull data from a DLCI and send it into the transmit queue if there 834 * is data. Keep to the MRU of the mux. This path handles framed data 835 * queued as skbuffs to the DLCI. 836 * 837 * Caller must hold the tx_lock of the mux. 838 */ 839 840 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, 841 struct gsm_dlci *dlci) 842 { 843 struct gsm_msg *msg; 844 u8 *dp; 845 int len, size; 846 int last = 0, first = 0; 847 int overhead = 0; 848 849 /* One byte per frame is used for B/F flags */ 850 if (dlci->adaption == 4) 851 overhead = 1; 852 853 /* dlci->skb is locked by tx_lock */ 854 if (dlci->skb == NULL) { 855 dlci->skb = skb_dequeue_tail(&dlci->skb_list); 856 if (dlci->skb == NULL) 857 return 0; 858 first = 1; 859 } 860 len = dlci->skb->len + overhead; 861 862 /* MTU/MRU count only the data bits */ 863 if (len > gsm->mtu) { 864 if (dlci->adaption == 3) { 865 /* Over long frame, bin it */ 866 dev_kfree_skb_any(dlci->skb); 867 dlci->skb = NULL; 868 return 0; 869 } 870 len = gsm->mtu; 871 } else 872 last = 1; 873 874 size = len + overhead; 875 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); 876 877 /* FIXME: need a timer or something to kick this so it can't 878 get stuck with no work outstanding and no buffer free */ 879 if (msg == NULL) { 880 skb_queue_tail(&dlci->skb_list, dlci->skb); 881 dlci->skb = NULL; 882 return -ENOMEM; 883 } 884 dp = msg->data; 885 886 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */ 887 /* Flag byte to carry the start/end info */ 888 *dp++ = last << 7 | first << 6 | 1; /* EA */ 889 len--; 890 } 891 memcpy(dp, dlci->skb->data, len); 892 skb_pull(dlci->skb, len); 893 __gsm_data_queue(dlci, msg); 894 if (last) { 895 dev_kfree_skb_any(dlci->skb); 896 dlci->skb = NULL; 897 } 898 return size; 899 } 900 901 /** 902 * gsm_dlci_data_sweep - look for data to send 903 * @gsm: the GSM mux 904 * 905 * Sweep the GSM mux channels in priority order looking for ones with 906 * data to send. We could do with optimising this scan a bit. We aim 907 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit 908 * TX_THRESH_LO we get called again 909 * 910 * FIXME: We should round robin between groups and in theory you can 911 * renegotiate DLCI priorities with optional stuff. Needs optimising. 912 */ 913 914 static void gsm_dlci_data_sweep(struct gsm_mux *gsm) 915 { 916 int len; 917 /* Priority ordering: We should do priority with RR of the groups */ 918 int i = 1; 919 920 while (i < NUM_DLCI) { 921 struct gsm_dlci *dlci; 922 923 if (gsm->tx_bytes > TX_THRESH_HI) 924 break; 925 dlci = gsm->dlci[i]; 926 if (dlci == NULL || dlci->constipated) { 927 i++; 928 continue; 929 } 930 if (dlci->adaption < 3 && !dlci->net) 931 len = gsm_dlci_data_output(gsm, dlci); 932 else 933 len = gsm_dlci_data_output_framed(gsm, dlci); 934 if (len < 0) 935 break; 936 /* DLCI empty - try the next */ 937 if (len == 0) 938 i++; 939 } 940 } 941 942 /** 943 * gsm_dlci_data_kick - transmit if possible 944 * @dlci: DLCI to kick 945 * 946 * Transmit data from this DLCI if the queue is empty. We can't rely on 947 * a tty wakeup except when we filled the pipe so we need to fire off 948 * new data ourselves in other cases. 949 */ 950 951 static void gsm_dlci_data_kick(struct gsm_dlci *dlci) 952 { 953 unsigned long flags; 954 int sweep; 955 956 if (dlci->constipated) 957 return; 958 959 spin_lock_irqsave(&dlci->gsm->tx_lock, flags); 960 /* If we have nothing running then we need to fire up */ 961 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO); 962 if (dlci->gsm->tx_bytes == 0) { 963 if (dlci->net) 964 gsm_dlci_data_output_framed(dlci->gsm, dlci); 965 else 966 gsm_dlci_data_output(dlci->gsm, dlci); 967 } 968 if (sweep) 969 gsm_dlci_data_sweep(dlci->gsm); 970 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); 971 } 972 973 /* 974 * Control message processing 975 */ 976 977 978 /** 979 * gsm_control_reply - send a response frame to a control 980 * @gsm: gsm channel 981 * @cmd: the command to use 982 * @data: data to follow encoded info 983 * @dlen: length of data 984 * 985 * Encode up and queue a UI/UIH frame containing our response. 986 */ 987 988 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data, 989 int dlen) 990 { 991 struct gsm_msg *msg; 992 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype); 993 if (msg == NULL) 994 return; 995 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */ 996 msg->data[1] = (dlen << 1) | EA; 997 memcpy(msg->data + 2, data, dlen); 998 gsm_data_queue(gsm->dlci[0], msg); 999 } 1000 1001 /** 1002 * gsm_process_modem - process received modem status 1003 * @tty: virtual tty bound to the DLCI 1004 * @dlci: DLCI to affect 1005 * @modem: modem bits (full EA) 1006 * 1007 * Used when a modem control message or line state inline in adaption 1008 * layer 2 is processed. Sort out the local modem state and throttles 1009 */ 1010 1011 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci, 1012 u32 modem, int clen) 1013 { 1014 int mlines = 0; 1015 u8 brk = 0; 1016 int fc; 1017 1018 /* The modem status command can either contain one octet (v.24 signals) 1019 or two octets (v.24 signals + break signals). The length field will 1020 either be 2 or 3 respectively. This is specified in section 1021 5.4.6.3.7 of the 27.010 mux spec. */ 1022 1023 if (clen == 2) 1024 modem = modem & 0x7f; 1025 else { 1026 brk = modem & 0x7f; 1027 modem = (modem >> 7) & 0x7f; 1028 } 1029 1030 /* Flow control/ready to communicate */ 1031 fc = (modem & MDM_FC) || !(modem & MDM_RTR); 1032 if (fc && !dlci->constipated) { 1033 /* Need to throttle our output on this device */ 1034 dlci->constipated = 1; 1035 } else if (!fc && dlci->constipated) { 1036 dlci->constipated = 0; 1037 gsm_dlci_data_kick(dlci); 1038 } 1039 1040 /* Map modem bits */ 1041 if (modem & MDM_RTC) 1042 mlines |= TIOCM_DSR | TIOCM_DTR; 1043 if (modem & MDM_RTR) 1044 mlines |= TIOCM_RTS | TIOCM_CTS; 1045 if (modem & MDM_IC) 1046 mlines |= TIOCM_RI; 1047 if (modem & MDM_DV) 1048 mlines |= TIOCM_CD; 1049 1050 /* Carrier drop -> hangup */ 1051 if (tty) { 1052 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD)) 1053 if (!C_CLOCAL(tty)) 1054 tty_hangup(tty); 1055 } 1056 if (brk & 0x01) 1057 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK); 1058 dlci->modem_rx = mlines; 1059 } 1060 1061 /** 1062 * gsm_control_modem - modem status received 1063 * @gsm: GSM channel 1064 * @data: data following command 1065 * @clen: command length 1066 * 1067 * We have received a modem status control message. This is used by 1068 * the GSM mux protocol to pass virtual modem line status and optionally 1069 * to indicate break signals. Unpack it, convert to Linux representation 1070 * and if need be stuff a break message down the tty. 1071 */ 1072 1073 static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen) 1074 { 1075 unsigned int addr = 0; 1076 unsigned int modem = 0; 1077 unsigned int brk = 0; 1078 struct gsm_dlci *dlci; 1079 int len = clen; 1080 u8 *dp = data; 1081 struct tty_struct *tty; 1082 1083 while (gsm_read_ea(&addr, *dp++) == 0) { 1084 len--; 1085 if (len == 0) 1086 return; 1087 } 1088 /* Must be at least one byte following the EA */ 1089 len--; 1090 if (len <= 0) 1091 return; 1092 1093 addr >>= 1; 1094 /* Closed port, or invalid ? */ 1095 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) 1096 return; 1097 dlci = gsm->dlci[addr]; 1098 1099 while (gsm_read_ea(&modem, *dp++) == 0) { 1100 len--; 1101 if (len == 0) 1102 return; 1103 } 1104 len--; 1105 if (len > 0) { 1106 while (gsm_read_ea(&brk, *dp++) == 0) { 1107 len--; 1108 if (len == 0) 1109 return; 1110 } 1111 modem <<= 7; 1112 modem |= (brk & 0x7f); 1113 } 1114 tty = tty_port_tty_get(&dlci->port); 1115 gsm_process_modem(tty, dlci, modem, clen); 1116 if (tty) { 1117 tty_wakeup(tty); 1118 tty_kref_put(tty); 1119 } 1120 gsm_control_reply(gsm, CMD_MSC, data, clen); 1121 } 1122 1123 /** 1124 * gsm_control_rls - remote line status 1125 * @gsm: GSM channel 1126 * @data: data bytes 1127 * @clen: data length 1128 * 1129 * The modem sends us a two byte message on the control channel whenever 1130 * it wishes to send us an error state from the virtual link. Stuff 1131 * this into the uplink tty if present 1132 */ 1133 1134 static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen) 1135 { 1136 struct tty_port *port; 1137 unsigned int addr = 0; 1138 u8 bits; 1139 int len = clen; 1140 u8 *dp = data; 1141 1142 while (gsm_read_ea(&addr, *dp++) == 0) { 1143 len--; 1144 if (len == 0) 1145 return; 1146 } 1147 /* Must be at least one byte following ea */ 1148 len--; 1149 if (len <= 0) 1150 return; 1151 addr >>= 1; 1152 /* Closed port, or invalid ? */ 1153 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) 1154 return; 1155 /* No error ? */ 1156 bits = *dp; 1157 if ((bits & 1) == 0) 1158 return; 1159 1160 port = &gsm->dlci[addr]->port; 1161 1162 if (bits & 2) 1163 tty_insert_flip_char(port, 0, TTY_OVERRUN); 1164 if (bits & 4) 1165 tty_insert_flip_char(port, 0, TTY_PARITY); 1166 if (bits & 8) 1167 tty_insert_flip_char(port, 0, TTY_FRAME); 1168 1169 tty_flip_buffer_push(port); 1170 1171 gsm_control_reply(gsm, CMD_RLS, data, clen); 1172 } 1173 1174 static void gsm_dlci_begin_close(struct gsm_dlci *dlci); 1175 1176 /** 1177 * gsm_control_message - DLCI 0 control processing 1178 * @gsm: our GSM mux 1179 * @command: the command EA 1180 * @data: data beyond the command/length EAs 1181 * @clen: length 1182 * 1183 * Input processor for control messages from the other end of the link. 1184 * Processes the incoming request and queues a response frame or an 1185 * NSC response if not supported 1186 */ 1187 1188 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, 1189 u8 *data, int clen) 1190 { 1191 u8 buf[1]; 1192 unsigned long flags; 1193 1194 switch (command) { 1195 case CMD_CLD: { 1196 struct gsm_dlci *dlci = gsm->dlci[0]; 1197 /* Modem wishes to close down */ 1198 if (dlci) { 1199 dlci->dead = 1; 1200 gsm->dead = 1; 1201 gsm_dlci_begin_close(dlci); 1202 } 1203 } 1204 break; 1205 case CMD_TEST: 1206 /* Modem wishes to test, reply with the data */ 1207 gsm_control_reply(gsm, CMD_TEST, data, clen); 1208 break; 1209 case CMD_FCON: 1210 /* Modem can accept data again */ 1211 gsm->constipated = 0; 1212 gsm_control_reply(gsm, CMD_FCON, NULL, 0); 1213 /* Kick the link in case it is idling */ 1214 spin_lock_irqsave(&gsm->tx_lock, flags); 1215 gsm_data_kick(gsm); 1216 spin_unlock_irqrestore(&gsm->tx_lock, flags); 1217 break; 1218 case CMD_FCOFF: 1219 /* Modem wants us to STFU */ 1220 gsm->constipated = 1; 1221 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0); 1222 break; 1223 case CMD_MSC: 1224 /* Out of band modem line change indicator for a DLCI */ 1225 gsm_control_modem(gsm, data, clen); 1226 break; 1227 case CMD_RLS: 1228 /* Out of band error reception for a DLCI */ 1229 gsm_control_rls(gsm, data, clen); 1230 break; 1231 case CMD_PSC: 1232 /* Modem wishes to enter power saving state */ 1233 gsm_control_reply(gsm, CMD_PSC, NULL, 0); 1234 break; 1235 /* Optional unsupported commands */ 1236 case CMD_PN: /* Parameter negotiation */ 1237 case CMD_RPN: /* Remote port negotiation */ 1238 case CMD_SNC: /* Service negotiation command */ 1239 default: 1240 /* Reply to bad commands with an NSC */ 1241 buf[0] = command; 1242 gsm_control_reply(gsm, CMD_NSC, buf, 1); 1243 break; 1244 } 1245 } 1246 1247 /** 1248 * gsm_control_response - process a response to our control 1249 * @gsm: our GSM mux 1250 * @command: the command (response) EA 1251 * @data: data beyond the command/length EA 1252 * @clen: length 1253 * 1254 * Process a response to an outstanding command. We only allow a single 1255 * control message in flight so this is fairly easy. All the clean up 1256 * is done by the caller, we just update the fields, flag it as done 1257 * and return 1258 */ 1259 1260 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command, 1261 u8 *data, int clen) 1262 { 1263 struct gsm_control *ctrl; 1264 unsigned long flags; 1265 1266 spin_lock_irqsave(&gsm->control_lock, flags); 1267 1268 ctrl = gsm->pending_cmd; 1269 /* Does the reply match our command */ 1270 command |= 1; 1271 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) { 1272 /* Our command was replied to, kill the retry timer */ 1273 del_timer(&gsm->t2_timer); 1274 gsm->pending_cmd = NULL; 1275 /* Rejected by the other end */ 1276 if (command == CMD_NSC) 1277 ctrl->error = -EOPNOTSUPP; 1278 ctrl->done = 1; 1279 wake_up(&gsm->event); 1280 } 1281 spin_unlock_irqrestore(&gsm->control_lock, flags); 1282 } 1283 1284 /** 1285 * gsm_control_transmit - send control packet 1286 * @gsm: gsm mux 1287 * @ctrl: frame to send 1288 * 1289 * Send out a pending control command (called under control lock) 1290 */ 1291 1292 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl) 1293 { 1294 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype); 1295 if (msg == NULL) 1296 return; 1297 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */ 1298 memcpy(msg->data + 1, ctrl->data, ctrl->len); 1299 gsm_data_queue(gsm->dlci[0], msg); 1300 } 1301 1302 /** 1303 * gsm_control_retransmit - retransmit a control frame 1304 * @data: pointer to our gsm object 1305 * 1306 * Called off the T2 timer expiry in order to retransmit control frames 1307 * that have been lost in the system somewhere. The control_lock protects 1308 * us from colliding with another sender or a receive completion event. 1309 * In that situation the timer may still occur in a small window but 1310 * gsm->pending_cmd will be NULL and we just let the timer expire. 1311 */ 1312 1313 static void gsm_control_retransmit(struct timer_list *t) 1314 { 1315 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer); 1316 struct gsm_control *ctrl; 1317 unsigned long flags; 1318 spin_lock_irqsave(&gsm->control_lock, flags); 1319 ctrl = gsm->pending_cmd; 1320 if (ctrl) { 1321 gsm->cretries--; 1322 if (gsm->cretries == 0) { 1323 gsm->pending_cmd = NULL; 1324 ctrl->error = -ETIMEDOUT; 1325 ctrl->done = 1; 1326 spin_unlock_irqrestore(&gsm->control_lock, flags); 1327 wake_up(&gsm->event); 1328 return; 1329 } 1330 gsm_control_transmit(gsm, ctrl); 1331 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); 1332 } 1333 spin_unlock_irqrestore(&gsm->control_lock, flags); 1334 } 1335 1336 /** 1337 * gsm_control_send - send a control frame on DLCI 0 1338 * @gsm: the GSM channel 1339 * @command: command to send including CR bit 1340 * @data: bytes of data (must be kmalloced) 1341 * @len: length of the block to send 1342 * 1343 * Queue and dispatch a control command. Only one command can be 1344 * active at a time. In theory more can be outstanding but the matching 1345 * gets really complicated so for now stick to one outstanding. 1346 */ 1347 1348 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm, 1349 unsigned int command, u8 *data, int clen) 1350 { 1351 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control), 1352 GFP_KERNEL); 1353 unsigned long flags; 1354 if (ctrl == NULL) 1355 return NULL; 1356 retry: 1357 wait_event(gsm->event, gsm->pending_cmd == NULL); 1358 spin_lock_irqsave(&gsm->control_lock, flags); 1359 if (gsm->pending_cmd != NULL) { 1360 spin_unlock_irqrestore(&gsm->control_lock, flags); 1361 goto retry; 1362 } 1363 ctrl->cmd = command; 1364 ctrl->data = data; 1365 ctrl->len = clen; 1366 gsm->pending_cmd = ctrl; 1367 gsm->cretries = gsm->n2; 1368 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); 1369 gsm_control_transmit(gsm, ctrl); 1370 spin_unlock_irqrestore(&gsm->control_lock, flags); 1371 return ctrl; 1372 } 1373 1374 /** 1375 * gsm_control_wait - wait for a control to finish 1376 * @gsm: GSM mux 1377 * @control: control we are waiting on 1378 * 1379 * Waits for the control to complete or time out. Frees any used 1380 * resources and returns 0 for success, or an error if the remote 1381 * rejected or ignored the request. 1382 */ 1383 1384 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control) 1385 { 1386 int err; 1387 wait_event(gsm->event, control->done == 1); 1388 err = control->error; 1389 kfree(control); 1390 return err; 1391 } 1392 1393 1394 /* 1395 * DLCI level handling: Needs krefs 1396 */ 1397 1398 /* 1399 * State transitions and timers 1400 */ 1401 1402 /** 1403 * gsm_dlci_close - a DLCI has closed 1404 * @dlci: DLCI that closed 1405 * 1406 * Perform processing when moving a DLCI into closed state. If there 1407 * is an attached tty this is hung up 1408 */ 1409 1410 static void gsm_dlci_close(struct gsm_dlci *dlci) 1411 { 1412 del_timer(&dlci->t1); 1413 if (debug & 8) 1414 pr_debug("DLCI %d goes closed.\n", dlci->addr); 1415 dlci->state = DLCI_CLOSED; 1416 if (dlci->addr != 0) { 1417 tty_port_tty_hangup(&dlci->port, false); 1418 kfifo_reset(dlci->fifo); 1419 } else 1420 dlci->gsm->dead = 1; 1421 wake_up(&dlci->gsm->event); 1422 /* A DLCI 0 close is a MUX termination so we need to kick that 1423 back to userspace somehow */ 1424 } 1425 1426 /** 1427 * gsm_dlci_open - a DLCI has opened 1428 * @dlci: DLCI that opened 1429 * 1430 * Perform processing when moving a DLCI into open state. 1431 */ 1432 1433 static void gsm_dlci_open(struct gsm_dlci *dlci) 1434 { 1435 /* Note that SABM UA .. SABM UA first UA lost can mean that we go 1436 open -> open */ 1437 del_timer(&dlci->t1); 1438 /* This will let a tty open continue */ 1439 dlci->state = DLCI_OPEN; 1440 if (debug & 8) 1441 pr_debug("DLCI %d goes open.\n", dlci->addr); 1442 wake_up(&dlci->gsm->event); 1443 } 1444 1445 /** 1446 * gsm_dlci_t1 - T1 timer expiry 1447 * @dlci: DLCI that opened 1448 * 1449 * The T1 timer handles retransmits of control frames (essentially of 1450 * SABM and DISC). We resend the command until the retry count runs out 1451 * in which case an opening port goes back to closed and a closing port 1452 * is simply put into closed state (any further frames from the other 1453 * end will get a DM response) 1454 * 1455 * Some control dlci can stay in ADM mode with other dlci working just 1456 * fine. In that case we can just keep the control dlci open after the 1457 * DLCI_OPENING retries time out. 1458 */ 1459 1460 static void gsm_dlci_t1(struct timer_list *t) 1461 { 1462 struct gsm_dlci *dlci = from_timer(dlci, t, t1); 1463 struct gsm_mux *gsm = dlci->gsm; 1464 1465 switch (dlci->state) { 1466 case DLCI_OPENING: 1467 dlci->retries--; 1468 if (dlci->retries) { 1469 gsm_command(dlci->gsm, dlci->addr, SABM|PF); 1470 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1471 } else if (!dlci->addr && gsm->control == (DM | PF)) { 1472 if (debug & 8) 1473 pr_info("DLCI %d opening in ADM mode.\n", 1474 dlci->addr); 1475 gsm_dlci_open(dlci); 1476 } else { 1477 gsm_dlci_close(dlci); 1478 } 1479 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 or ADM, at which point 1498 * we will move into open state. Opening is done asynchronously with retry 1499 * running off timers and the responses. 1500 */ 1501 1502 static 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 1524 static 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 1546 static 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; 1551 unsigned int modem = 0; 1552 int len = clen; 1553 1554 if (debug & 16) 1555 pr_debug("%d bytes for tty\n", len); 1556 switch (dlci->adaption) { 1557 /* Unsupported types */ 1558 /* Packetised interruptible data */ 1559 case 4: 1560 break; 1561 /* Packetised uininterruptible voice/data */ 1562 case 3: 1563 break; 1564 /* Asynchronous serial with line state in each frame */ 1565 case 2: 1566 while (gsm_read_ea(&modem, *data++) == 0) { 1567 len--; 1568 if (len == 0) 1569 return; 1570 } 1571 tty = tty_port_tty_get(port); 1572 if (tty) { 1573 gsm_process_modem(tty, dlci, modem, clen); 1574 tty_kref_put(tty); 1575 } 1576 /* Line state will go via DLCI 0 controls only */ 1577 case 1: 1578 default: 1579 tty_insert_flip_string(port, data, len); 1580 tty_flip_buffer_push(port); 1581 } 1582 } 1583 1584 /** 1585 * gsm_dlci_control - data arrived on control channel 1586 * @dlci: channel 1587 * @data: block of bytes received 1588 * @len: length of received block 1589 * 1590 * A UI or UIH frame has arrived which contains data for DLCI 0 the 1591 * control channel. This should contain a command EA followed by 1592 * control data bytes. The command EA contains a command/response bit 1593 * and we divide up the work accordingly. 1594 */ 1595 1596 static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len) 1597 { 1598 /* See what command is involved */ 1599 unsigned int command = 0; 1600 while (len-- > 0) { 1601 if (gsm_read_ea(&command, *data++) == 1) { 1602 int clen = *data++; 1603 len--; 1604 /* FIXME: this is properly an EA */ 1605 clen >>= 1; 1606 /* Malformed command ? */ 1607 if (clen > len) 1608 return; 1609 if (command & 1) 1610 gsm_control_message(dlci->gsm, command, 1611 data, clen); 1612 else 1613 gsm_control_response(dlci->gsm, command, 1614 data, clen); 1615 return; 1616 } 1617 } 1618 } 1619 1620 /* 1621 * Allocate/Free DLCI channels 1622 */ 1623 1624 /** 1625 * gsm_dlci_alloc - allocate a DLCI 1626 * @gsm: GSM mux 1627 * @addr: address of the DLCI 1628 * 1629 * Allocate and install a new DLCI object into the GSM mux. 1630 * 1631 * FIXME: review locking races 1632 */ 1633 1634 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr) 1635 { 1636 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC); 1637 if (dlci == NULL) 1638 return NULL; 1639 spin_lock_init(&dlci->lock); 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 timer_setup(&dlci->t1, gsm_dlci_t1, 0); 1649 tty_port_init(&dlci->port); 1650 dlci->port.ops = &gsm_port_ops; 1651 dlci->gsm = gsm; 1652 dlci->addr = addr; 1653 dlci->adaption = gsm->adaption; 1654 dlci->state = DLCI_CLOSED; 1655 if (addr) 1656 dlci->data = gsm_dlci_data; 1657 else 1658 dlci->data = gsm_dlci_command; 1659 gsm->dlci[addr] = dlci; 1660 return dlci; 1661 } 1662 1663 /** 1664 * gsm_dlci_free - free DLCI 1665 * @dlci: DLCI to free 1666 * 1667 * Free up a DLCI. 1668 * 1669 * Can sleep. 1670 */ 1671 static void gsm_dlci_free(struct tty_port *port) 1672 { 1673 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 1674 1675 del_timer_sync(&dlci->t1); 1676 dlci->gsm->dlci[dlci->addr] = NULL; 1677 kfifo_free(dlci->fifo); 1678 while ((dlci->skb = skb_dequeue(&dlci->skb_list))) 1679 dev_kfree_skb(dlci->skb); 1680 kfree(dlci); 1681 } 1682 1683 static inline void dlci_get(struct gsm_dlci *dlci) 1684 { 1685 tty_port_get(&dlci->port); 1686 } 1687 1688 static inline void dlci_put(struct gsm_dlci *dlci) 1689 { 1690 tty_port_put(&dlci->port); 1691 } 1692 1693 static void gsm_destroy_network(struct gsm_dlci *dlci); 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 */ 1704 static void gsm_dlci_release(struct gsm_dlci *dlci) 1705 { 1706 struct tty_struct *tty = tty_port_tty_get(&dlci->port); 1707 if (tty) { 1708 mutex_lock(&dlci->mutex); 1709 gsm_destroy_network(dlci); 1710 mutex_unlock(&dlci->mutex); 1711 1712 tty_vhangup(tty); 1713 1714 tty_port_tty_set(&dlci->port, NULL); 1715 tty_kref_put(tty); 1716 } 1717 dlci->state = DLCI_CLOSED; 1718 dlci_put(dlci); 1719 } 1720 1721 /* 1722 * LAPBish link layer logic 1723 */ 1724 1725 /** 1726 * gsm_queue - a GSM frame is ready to process 1727 * @gsm: pointer to our gsm mux 1728 * 1729 * At this point in time a frame has arrived and been demangled from 1730 * the line encoding. All the differences between the encodings have 1731 * been handled below us and the frame is unpacked into the structures. 1732 * The fcs holds the header FCS but any data FCS must be added here. 1733 */ 1734 1735 static void gsm_queue(struct gsm_mux *gsm) 1736 { 1737 struct gsm_dlci *dlci; 1738 u8 cr; 1739 int address; 1740 /* We have to sneak a look at the packet body to do the FCS. 1741 A somewhat layering violation in the spec */ 1742 1743 if ((gsm->control & ~PF) == UI) 1744 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len); 1745 if (gsm->encoding == 0) { 1746 /* WARNING: gsm->received_fcs is used for 1747 gsm->encoding = 0 only. 1748 In this case it contain the last piece of data 1749 required to generate final CRC */ 1750 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs); 1751 } 1752 if (gsm->fcs != GOOD_FCS) { 1753 gsm->bad_fcs++; 1754 if (debug & 4) 1755 pr_debug("BAD FCS %02x\n", gsm->fcs); 1756 return; 1757 } 1758 address = gsm->address >> 1; 1759 if (address >= NUM_DLCI) 1760 goto invalid; 1761 1762 cr = gsm->address & 1; /* C/R bit */ 1763 1764 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len); 1765 1766 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */ 1767 dlci = gsm->dlci[address]; 1768 1769 switch (gsm->control) { 1770 case SABM|PF: 1771 if (cr == 0) 1772 goto invalid; 1773 if (dlci == NULL) 1774 dlci = gsm_dlci_alloc(gsm, address); 1775 if (dlci == NULL) 1776 return; 1777 if (dlci->dead) 1778 gsm_response(gsm, address, DM); 1779 else { 1780 gsm_response(gsm, address, UA); 1781 gsm_dlci_open(dlci); 1782 } 1783 break; 1784 case DISC|PF: 1785 if (cr == 0) 1786 goto invalid; 1787 if (dlci == NULL || dlci->state == DLCI_CLOSED) { 1788 gsm_response(gsm, address, DM); 1789 return; 1790 } 1791 /* Real close complete */ 1792 gsm_response(gsm, address, UA); 1793 gsm_dlci_close(dlci); 1794 break; 1795 case UA: 1796 case UA|PF: 1797 if (cr == 0 || dlci == NULL) 1798 break; 1799 switch (dlci->state) { 1800 case DLCI_CLOSING: 1801 gsm_dlci_close(dlci); 1802 break; 1803 case DLCI_OPENING: 1804 gsm_dlci_open(dlci); 1805 break; 1806 } 1807 break; 1808 case DM: /* DM can be valid unsolicited */ 1809 case DM|PF: 1810 if (cr) 1811 goto invalid; 1812 if (dlci == NULL) 1813 return; 1814 gsm_dlci_close(dlci); 1815 break; 1816 case UI: 1817 case UI|PF: 1818 case UIH: 1819 case UIH|PF: 1820 #if 0 1821 if (cr) 1822 goto invalid; 1823 #endif 1824 if (dlci == NULL || dlci->state != DLCI_OPEN) { 1825 gsm_command(gsm, address, DM|PF); 1826 return; 1827 } 1828 dlci->data(dlci, gsm->buf, gsm->len); 1829 break; 1830 default: 1831 goto invalid; 1832 } 1833 return; 1834 invalid: 1835 gsm->malformed++; 1836 return; 1837 } 1838 1839 1840 /** 1841 * gsm0_receive - perform processing for non-transparency 1842 * @gsm: gsm data for this ldisc instance 1843 * @c: character 1844 * 1845 * Receive bytes in gsm mode 0 1846 */ 1847 1848 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) 1849 { 1850 unsigned int len; 1851 1852 switch (gsm->state) { 1853 case GSM_SEARCH: /* SOF marker */ 1854 if (c == GSM0_SOF) { 1855 gsm->state = GSM_ADDRESS; 1856 gsm->address = 0; 1857 gsm->len = 0; 1858 gsm->fcs = INIT_FCS; 1859 } 1860 break; 1861 case GSM_ADDRESS: /* Address EA */ 1862 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1863 if (gsm_read_ea(&gsm->address, c)) 1864 gsm->state = GSM_CONTROL; 1865 break; 1866 case GSM_CONTROL: /* Control Byte */ 1867 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1868 gsm->control = c; 1869 gsm->state = GSM_LEN0; 1870 break; 1871 case GSM_LEN0: /* Length EA */ 1872 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1873 if (gsm_read_ea(&gsm->len, c)) { 1874 if (gsm->len > gsm->mru) { 1875 gsm->bad_size++; 1876 gsm->state = GSM_SEARCH; 1877 break; 1878 } 1879 gsm->count = 0; 1880 if (!gsm->len) 1881 gsm->state = GSM_FCS; 1882 else 1883 gsm->state = GSM_DATA; 1884 break; 1885 } 1886 gsm->state = GSM_LEN1; 1887 break; 1888 case GSM_LEN1: 1889 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1890 len = c; 1891 gsm->len |= len << 7; 1892 if (gsm->len > gsm->mru) { 1893 gsm->bad_size++; 1894 gsm->state = GSM_SEARCH; 1895 break; 1896 } 1897 gsm->count = 0; 1898 if (!gsm->len) 1899 gsm->state = GSM_FCS; 1900 else 1901 gsm->state = GSM_DATA; 1902 break; 1903 case GSM_DATA: /* Data */ 1904 gsm->buf[gsm->count++] = c; 1905 if (gsm->count == gsm->len) 1906 gsm->state = GSM_FCS; 1907 break; 1908 case GSM_FCS: /* FCS follows the packet */ 1909 gsm->received_fcs = c; 1910 gsm_queue(gsm); 1911 gsm->state = GSM_SSOF; 1912 break; 1913 case GSM_SSOF: 1914 if (c == GSM0_SOF) { 1915 gsm->state = GSM_SEARCH; 1916 break; 1917 } 1918 break; 1919 } 1920 } 1921 1922 /** 1923 * gsm1_receive - perform processing for non-transparency 1924 * @gsm: gsm data for this ldisc instance 1925 * @c: character 1926 * 1927 * Receive bytes in mode 1 (Advanced option) 1928 */ 1929 1930 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c) 1931 { 1932 if (c == GSM1_SOF) { 1933 /* EOF is only valid in frame if we have got to the data state 1934 and received at least one byte (the FCS) */ 1935 if (gsm->state == GSM_DATA && gsm->count) { 1936 /* Extract the FCS */ 1937 gsm->count--; 1938 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]); 1939 gsm->len = gsm->count; 1940 gsm_queue(gsm); 1941 gsm->state = GSM_START; 1942 return; 1943 } 1944 /* Any partial frame was a runt so go back to start */ 1945 if (gsm->state != GSM_START) { 1946 gsm->malformed++; 1947 gsm->state = GSM_START; 1948 } 1949 /* A SOF in GSM_START means we are still reading idling or 1950 framing bytes */ 1951 return; 1952 } 1953 1954 if (c == GSM1_ESCAPE) { 1955 gsm->escape = 1; 1956 return; 1957 } 1958 1959 /* Only an unescaped SOF gets us out of GSM search */ 1960 if (gsm->state == GSM_SEARCH) 1961 return; 1962 1963 if (gsm->escape) { 1964 c ^= GSM1_ESCAPE_BITS; 1965 gsm->escape = 0; 1966 } 1967 switch (gsm->state) { 1968 case GSM_START: /* First byte after SOF */ 1969 gsm->address = 0; 1970 gsm->state = GSM_ADDRESS; 1971 gsm->fcs = INIT_FCS; 1972 /* Drop through */ 1973 case GSM_ADDRESS: /* Address continuation */ 1974 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1975 if (gsm_read_ea(&gsm->address, c)) 1976 gsm->state = GSM_CONTROL; 1977 break; 1978 case GSM_CONTROL: /* Control Byte */ 1979 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1980 gsm->control = c; 1981 gsm->count = 0; 1982 gsm->state = GSM_DATA; 1983 break; 1984 case GSM_DATA: /* Data */ 1985 if (gsm->count > gsm->mru) { /* Allow one for the FCS */ 1986 gsm->state = GSM_OVERRUN; 1987 gsm->bad_size++; 1988 } else 1989 gsm->buf[gsm->count++] = c; 1990 break; 1991 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */ 1992 break; 1993 } 1994 } 1995 1996 /** 1997 * gsm_error - handle tty error 1998 * @gsm: ldisc data 1999 * @data: byte received (may be invalid) 2000 * @flag: error received 2001 * 2002 * Handle an error in the receipt of data for a frame. Currently we just 2003 * go back to hunting for a SOF. 2004 * 2005 * FIXME: better diagnostics ? 2006 */ 2007 2008 static void gsm_error(struct gsm_mux *gsm, 2009 unsigned char data, unsigned char flag) 2010 { 2011 gsm->state = GSM_SEARCH; 2012 gsm->io_error++; 2013 } 2014 2015 static int gsm_disconnect(struct gsm_mux *gsm) 2016 { 2017 struct gsm_dlci *dlci = gsm->dlci[0]; 2018 struct gsm_control *gc; 2019 2020 if (!dlci) 2021 return 0; 2022 2023 /* In theory disconnecting DLCI 0 is sufficient but for some 2024 modems this is apparently not the case. */ 2025 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0); 2026 if (gc) 2027 gsm_control_wait(gsm, gc); 2028 2029 del_timer_sync(&gsm->t2_timer); 2030 /* Now we are sure T2 has stopped */ 2031 2032 gsm_dlci_begin_close(dlci); 2033 wait_event_interruptible(gsm->event, 2034 dlci->state == DLCI_CLOSED); 2035 2036 if (signal_pending(current)) 2037 return -EINTR; 2038 2039 return 0; 2040 } 2041 2042 /** 2043 * gsm_cleanup_mux - generic GSM protocol cleanup 2044 * @gsm: our mux 2045 * 2046 * Clean up the bits of the mux which are the same for all framing 2047 * protocols. Remove the mux from the mux table, stop all the timers 2048 * and then shut down each device hanging up the channels as we go. 2049 */ 2050 2051 static void gsm_cleanup_mux(struct gsm_mux *gsm) 2052 { 2053 int i; 2054 struct gsm_dlci *dlci = gsm->dlci[0]; 2055 struct gsm_msg *txq, *ntxq; 2056 2057 gsm->dead = 1; 2058 2059 spin_lock(&gsm_mux_lock); 2060 for (i = 0; i < MAX_MUX; i++) { 2061 if (gsm_mux[i] == gsm) { 2062 gsm_mux[i] = NULL; 2063 break; 2064 } 2065 } 2066 spin_unlock(&gsm_mux_lock); 2067 /* open failed before registering => nothing to do */ 2068 if (i == MAX_MUX) 2069 return; 2070 2071 del_timer_sync(&gsm->t2_timer); 2072 /* Now we are sure T2 has stopped */ 2073 if (dlci) 2074 dlci->dead = 1; 2075 2076 /* Free up any link layer users */ 2077 mutex_lock(&gsm->mutex); 2078 for (i = 0; i < NUM_DLCI; i++) 2079 if (gsm->dlci[i]) 2080 gsm_dlci_release(gsm->dlci[i]); 2081 mutex_unlock(&gsm->mutex); 2082 /* Now wipe the queues */ 2083 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list) 2084 kfree(txq); 2085 INIT_LIST_HEAD(&gsm->tx_list); 2086 } 2087 2088 /** 2089 * gsm_activate_mux - generic GSM setup 2090 * @gsm: our mux 2091 * 2092 * Set up the bits of the mux which are the same for all framing 2093 * protocols. Add the mux to the mux table so it can be opened and 2094 * finally kick off connecting to DLCI 0 on the modem. 2095 */ 2096 2097 static int gsm_activate_mux(struct gsm_mux *gsm) 2098 { 2099 struct gsm_dlci *dlci; 2100 int i = 0; 2101 2102 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0); 2103 init_waitqueue_head(&gsm->event); 2104 spin_lock_init(&gsm->control_lock); 2105 spin_lock_init(&gsm->tx_lock); 2106 2107 if (gsm->encoding == 0) 2108 gsm->receive = gsm0_receive; 2109 else 2110 gsm->receive = gsm1_receive; 2111 gsm->error = gsm_error; 2112 2113 spin_lock(&gsm_mux_lock); 2114 for (i = 0; i < MAX_MUX; i++) { 2115 if (gsm_mux[i] == NULL) { 2116 gsm->num = i; 2117 gsm_mux[i] = gsm; 2118 break; 2119 } 2120 } 2121 spin_unlock(&gsm_mux_lock); 2122 if (i == MAX_MUX) 2123 return -EBUSY; 2124 2125 dlci = gsm_dlci_alloc(gsm, 0); 2126 if (dlci == NULL) 2127 return -ENOMEM; 2128 gsm->dead = 0; /* Tty opens are now permissible */ 2129 return 0; 2130 } 2131 2132 /** 2133 * gsm_free_mux - free up a mux 2134 * @mux: mux to free 2135 * 2136 * Dispose of allocated resources for a dead mux 2137 */ 2138 static void gsm_free_mux(struct gsm_mux *gsm) 2139 { 2140 kfree(gsm->txframe); 2141 kfree(gsm->buf); 2142 kfree(gsm); 2143 } 2144 2145 /** 2146 * gsm_free_muxr - free up a mux 2147 * @mux: mux to free 2148 * 2149 * Dispose of allocated resources for a dead mux 2150 */ 2151 static void gsm_free_muxr(struct kref *ref) 2152 { 2153 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref); 2154 gsm_free_mux(gsm); 2155 } 2156 2157 static inline void mux_get(struct gsm_mux *gsm) 2158 { 2159 kref_get(&gsm->ref); 2160 } 2161 2162 static inline void mux_put(struct gsm_mux *gsm) 2163 { 2164 kref_put(&gsm->ref, gsm_free_muxr); 2165 } 2166 2167 /** 2168 * gsm_alloc_mux - allocate a mux 2169 * 2170 * Creates a new mux ready for activation. 2171 */ 2172 2173 static struct gsm_mux *gsm_alloc_mux(void) 2174 { 2175 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL); 2176 if (gsm == NULL) 2177 return NULL; 2178 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL); 2179 if (gsm->buf == NULL) { 2180 kfree(gsm); 2181 return NULL; 2182 } 2183 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL); 2184 if (gsm->txframe == NULL) { 2185 kfree(gsm->buf); 2186 kfree(gsm); 2187 return NULL; 2188 } 2189 spin_lock_init(&gsm->lock); 2190 mutex_init(&gsm->mutex); 2191 kref_init(&gsm->ref); 2192 INIT_LIST_HEAD(&gsm->tx_list); 2193 2194 gsm->t1 = T1; 2195 gsm->t2 = T2; 2196 gsm->n2 = N2; 2197 gsm->ftype = UIH; 2198 gsm->adaption = 1; 2199 gsm->encoding = 1; 2200 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */ 2201 gsm->mtu = 64; 2202 gsm->dead = 1; /* Avoid early tty opens */ 2203 2204 return gsm; 2205 } 2206 2207 /** 2208 * gsmld_output - write to link 2209 * @gsm: our mux 2210 * @data: bytes to output 2211 * @len: size 2212 * 2213 * Write a block of data from the GSM mux to the data channel. This 2214 * will eventually be serialized from above but at the moment isn't. 2215 */ 2216 2217 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len) 2218 { 2219 if (tty_write_room(gsm->tty) < len) { 2220 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags); 2221 return -ENOSPC; 2222 } 2223 if (debug & 4) 2224 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET, 2225 data, len); 2226 gsm->tty->ops->write(gsm->tty, data, len); 2227 return len; 2228 } 2229 2230 /** 2231 * gsmld_attach_gsm - mode set up 2232 * @tty: our tty structure 2233 * @gsm: our mux 2234 * 2235 * Set up the MUX for basic mode and commence connecting to the 2236 * modem. Currently called from the line discipline set up but 2237 * will need moving to an ioctl path. 2238 */ 2239 2240 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 2241 { 2242 int ret, i, base; 2243 2244 gsm->tty = tty_kref_get(tty); 2245 gsm->output = gsmld_output; 2246 ret = gsm_activate_mux(gsm); 2247 if (ret != 0) 2248 tty_kref_put(gsm->tty); 2249 else { 2250 /* Don't register device 0 - this is the control channel and not 2251 a usable tty interface */ 2252 base = gsm->num << 6; /* Base for this MUX */ 2253 for (i = 1; i < NUM_DLCI; i++) 2254 tty_register_device(gsm_tty_driver, base + i, NULL); 2255 } 2256 return ret; 2257 } 2258 2259 2260 /** 2261 * gsmld_detach_gsm - stop doing 0710 mux 2262 * @tty: tty attached to the mux 2263 * @gsm: mux 2264 * 2265 * Shutdown and then clean up the resources used by the line discipline 2266 */ 2267 2268 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 2269 { 2270 int i; 2271 int base = gsm->num << 6; /* Base for this MUX */ 2272 2273 WARN_ON(tty != gsm->tty); 2274 for (i = 1; i < NUM_DLCI; i++) 2275 tty_unregister_device(gsm_tty_driver, base + i); 2276 gsm_cleanup_mux(gsm); 2277 tty_kref_put(gsm->tty); 2278 gsm->tty = NULL; 2279 } 2280 2281 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, 2282 char *fp, int count) 2283 { 2284 struct gsm_mux *gsm = tty->disc_data; 2285 const unsigned char *dp; 2286 char *f; 2287 int i; 2288 char flags = TTY_NORMAL; 2289 2290 if (debug & 4) 2291 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET, 2292 cp, count); 2293 2294 for (i = count, dp = cp, f = fp; i; i--, dp++) { 2295 if (f) 2296 flags = *f++; 2297 switch (flags) { 2298 case TTY_NORMAL: 2299 gsm->receive(gsm, *dp); 2300 break; 2301 case TTY_OVERRUN: 2302 case TTY_BREAK: 2303 case TTY_PARITY: 2304 case TTY_FRAME: 2305 gsm->error(gsm, *dp, flags); 2306 break; 2307 default: 2308 WARN_ONCE(1, "%s: unknown flag %d\n", 2309 tty_name(tty), flags); 2310 break; 2311 } 2312 } 2313 /* FASYNC if needed ? */ 2314 /* If clogged call tty_throttle(tty); */ 2315 } 2316 2317 /** 2318 * gsmld_flush_buffer - clean input queue 2319 * @tty: terminal device 2320 * 2321 * Flush the input buffer. Called when the line discipline is 2322 * being closed, when the tty layer wants the buffer flushed (eg 2323 * at hangup). 2324 */ 2325 2326 static void gsmld_flush_buffer(struct tty_struct *tty) 2327 { 2328 } 2329 2330 /** 2331 * gsmld_close - close the ldisc for this tty 2332 * @tty: device 2333 * 2334 * Called from the terminal layer when this line discipline is 2335 * being shut down, either because of a close or becsuse of a 2336 * discipline change. The function will not be called while other 2337 * ldisc methods are in progress. 2338 */ 2339 2340 static void gsmld_close(struct tty_struct *tty) 2341 { 2342 struct gsm_mux *gsm = tty->disc_data; 2343 2344 gsmld_detach_gsm(tty, gsm); 2345 2346 gsmld_flush_buffer(tty); 2347 /* Do other clean up here */ 2348 mux_put(gsm); 2349 } 2350 2351 /** 2352 * gsmld_open - open an ldisc 2353 * @tty: terminal to open 2354 * 2355 * Called when this line discipline is being attached to the 2356 * terminal device. Can sleep. Called serialized so that no 2357 * other events will occur in parallel. No further open will occur 2358 * until a close. 2359 */ 2360 2361 static int gsmld_open(struct tty_struct *tty) 2362 { 2363 struct gsm_mux *gsm; 2364 int ret; 2365 2366 if (tty->ops->write == NULL) 2367 return -EINVAL; 2368 2369 /* Attach our ldisc data */ 2370 gsm = gsm_alloc_mux(); 2371 if (gsm == NULL) 2372 return -ENOMEM; 2373 2374 tty->disc_data = gsm; 2375 tty->receive_room = 65536; 2376 2377 /* Attach the initial passive connection */ 2378 gsm->encoding = 1; 2379 2380 ret = gsmld_attach_gsm(tty, gsm); 2381 if (ret != 0) { 2382 gsm_cleanup_mux(gsm); 2383 mux_put(gsm); 2384 } 2385 return ret; 2386 } 2387 2388 /** 2389 * gsmld_write_wakeup - asynchronous I/O notifier 2390 * @tty: tty device 2391 * 2392 * Required for the ptys, serial driver etc. since processes 2393 * that attach themselves to the master and rely on ASYNC 2394 * IO must be woken up 2395 */ 2396 2397 static void gsmld_write_wakeup(struct tty_struct *tty) 2398 { 2399 struct gsm_mux *gsm = tty->disc_data; 2400 unsigned long flags; 2401 2402 /* Queue poll */ 2403 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 2404 spin_lock_irqsave(&gsm->tx_lock, flags); 2405 gsm_data_kick(gsm); 2406 if (gsm->tx_bytes < TX_THRESH_LO) { 2407 gsm_dlci_data_sweep(gsm); 2408 } 2409 spin_unlock_irqrestore(&gsm->tx_lock, flags); 2410 } 2411 2412 /** 2413 * gsmld_read - read function for tty 2414 * @tty: tty device 2415 * @file: file object 2416 * @buf: userspace buffer pointer 2417 * @nr: size of I/O 2418 * 2419 * Perform reads for the line discipline. We are guaranteed that the 2420 * line discipline will not be closed under us but we may get multiple 2421 * parallel readers and must handle this ourselves. We may also get 2422 * a hangup. Always called in user context, may sleep. 2423 * 2424 * This code must be sure never to sleep through a hangup. 2425 */ 2426 2427 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, 2428 unsigned char __user *buf, size_t nr) 2429 { 2430 return -EOPNOTSUPP; 2431 } 2432 2433 /** 2434 * gsmld_write - write function for tty 2435 * @tty: tty device 2436 * @file: file object 2437 * @buf: userspace buffer pointer 2438 * @nr: size of I/O 2439 * 2440 * Called when the owner of the device wants to send a frame 2441 * itself (or some other control data). The data is transferred 2442 * as-is and must be properly framed and checksummed as appropriate 2443 * by userspace. Frames are either sent whole or not at all as this 2444 * avoids pain user side. 2445 */ 2446 2447 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file, 2448 const unsigned char *buf, size_t nr) 2449 { 2450 int space = tty_write_room(tty); 2451 if (space >= nr) 2452 return tty->ops->write(tty, buf, nr); 2453 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 2454 return -ENOBUFS; 2455 } 2456 2457 /** 2458 * gsmld_poll - poll method for N_GSM0710 2459 * @tty: terminal device 2460 * @file: file accessing it 2461 * @wait: poll table 2462 * 2463 * Called when the line discipline is asked to poll() for data or 2464 * for special events. This code is not serialized with respect to 2465 * other events save open/close. 2466 * 2467 * This code must be sure never to sleep through a hangup. 2468 * Called without the kernel lock held - fine 2469 */ 2470 2471 static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file, 2472 poll_table *wait) 2473 { 2474 __poll_t mask = 0; 2475 struct gsm_mux *gsm = tty->disc_data; 2476 2477 poll_wait(file, &tty->read_wait, wait); 2478 poll_wait(file, &tty->write_wait, wait); 2479 if (tty_hung_up_p(file)) 2480 mask |= EPOLLHUP; 2481 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0) 2482 mask |= EPOLLOUT | EPOLLWRNORM; 2483 if (gsm->dead) 2484 mask |= EPOLLHUP; 2485 return mask; 2486 } 2487 2488 static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm, 2489 struct gsm_config *c) 2490 { 2491 int need_close = 0; 2492 int need_restart = 0; 2493 2494 /* Stuff we don't support yet - UI or I frame transport, windowing */ 2495 if ((c->adaption != 1 && c->adaption != 2) || c->k) 2496 return -EOPNOTSUPP; 2497 /* Check the MRU/MTU range looks sane */ 2498 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8) 2499 return -EINVAL; 2500 if (c->n2 < 3) 2501 return -EINVAL; 2502 if (c->encapsulation > 1) /* Basic, advanced, no I */ 2503 return -EINVAL; 2504 if (c->initiator > 1) 2505 return -EINVAL; 2506 if (c->i == 0 || c->i > 2) /* UIH and UI only */ 2507 return -EINVAL; 2508 /* 2509 * See what is needed for reconfiguration 2510 */ 2511 2512 /* Timing fields */ 2513 if (c->t1 != 0 && c->t1 != gsm->t1) 2514 need_restart = 1; 2515 if (c->t2 != 0 && c->t2 != gsm->t2) 2516 need_restart = 1; 2517 if (c->encapsulation != gsm->encoding) 2518 need_restart = 1; 2519 if (c->adaption != gsm->adaption) 2520 need_restart = 1; 2521 /* Requires care */ 2522 if (c->initiator != gsm->initiator) 2523 need_close = 1; 2524 if (c->mru != gsm->mru) 2525 need_restart = 1; 2526 if (c->mtu != gsm->mtu) 2527 need_restart = 1; 2528 2529 /* 2530 * Close down what is needed, restart and initiate the new 2531 * configuration 2532 */ 2533 2534 if (need_close || need_restart) { 2535 int ret; 2536 2537 ret = gsm_disconnect(gsm); 2538 2539 if (ret) 2540 return ret; 2541 } 2542 if (need_restart) 2543 gsm_cleanup_mux(gsm); 2544 2545 gsm->initiator = c->initiator; 2546 gsm->mru = c->mru; 2547 gsm->mtu = c->mtu; 2548 gsm->encoding = c->encapsulation; 2549 gsm->adaption = c->adaption; 2550 gsm->n2 = c->n2; 2551 2552 if (c->i == 1) 2553 gsm->ftype = UIH; 2554 else if (c->i == 2) 2555 gsm->ftype = UI; 2556 2557 if (c->t1) 2558 gsm->t1 = c->t1; 2559 if (c->t2) 2560 gsm->t2 = c->t2; 2561 2562 /* FIXME: We need to separate activation/deactivation from adding 2563 and removing from the mux array */ 2564 if (need_restart) 2565 gsm_activate_mux(gsm); 2566 if (gsm->initiator && need_close) 2567 gsm_dlci_begin_open(gsm->dlci[0]); 2568 return 0; 2569 } 2570 2571 static int gsmld_ioctl(struct tty_struct *tty, struct file *file, 2572 unsigned int cmd, unsigned long arg) 2573 { 2574 struct gsm_config c; 2575 struct gsm_mux *gsm = tty->disc_data; 2576 2577 switch (cmd) { 2578 case GSMIOC_GETCONF: 2579 memset(&c, 0, sizeof(c)); 2580 c.adaption = gsm->adaption; 2581 c.encapsulation = gsm->encoding; 2582 c.initiator = gsm->initiator; 2583 c.t1 = gsm->t1; 2584 c.t2 = gsm->t2; 2585 c.t3 = 0; /* Not supported */ 2586 c.n2 = gsm->n2; 2587 if (gsm->ftype == UIH) 2588 c.i = 1; 2589 else 2590 c.i = 2; 2591 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i); 2592 c.mru = gsm->mru; 2593 c.mtu = gsm->mtu; 2594 c.k = 0; 2595 if (copy_to_user((void *)arg, &c, sizeof(c))) 2596 return -EFAULT; 2597 return 0; 2598 case GSMIOC_SETCONF: 2599 if (copy_from_user(&c, (void *)arg, sizeof(c))) 2600 return -EFAULT; 2601 return gsmld_config(tty, gsm, &c); 2602 default: 2603 return n_tty_ioctl_helper(tty, file, cmd, arg); 2604 } 2605 } 2606 2607 #ifdef CONFIG_COMPAT 2608 static long gsmld_compat_ioctl(struct tty_struct *tty, struct file *file, 2609 unsigned int cmd, unsigned long arg) 2610 { 2611 return gsmld_ioctl(tty, file, cmd, arg); 2612 } 2613 #endif 2614 2615 /* 2616 * Network interface 2617 * 2618 */ 2619 2620 static int gsm_mux_net_open(struct net_device *net) 2621 { 2622 pr_debug("%s called\n", __func__); 2623 netif_start_queue(net); 2624 return 0; 2625 } 2626 2627 static int gsm_mux_net_close(struct net_device *net) 2628 { 2629 netif_stop_queue(net); 2630 return 0; 2631 } 2632 2633 static void dlci_net_free(struct gsm_dlci *dlci) 2634 { 2635 if (!dlci->net) { 2636 WARN_ON(1); 2637 return; 2638 } 2639 dlci->adaption = dlci->prev_adaption; 2640 dlci->data = dlci->prev_data; 2641 free_netdev(dlci->net); 2642 dlci->net = NULL; 2643 } 2644 static void net_free(struct kref *ref) 2645 { 2646 struct gsm_mux_net *mux_net; 2647 struct gsm_dlci *dlci; 2648 2649 mux_net = container_of(ref, struct gsm_mux_net, ref); 2650 dlci = mux_net->dlci; 2651 2652 if (dlci->net) { 2653 unregister_netdev(dlci->net); 2654 dlci_net_free(dlci); 2655 } 2656 } 2657 2658 static inline void muxnet_get(struct gsm_mux_net *mux_net) 2659 { 2660 kref_get(&mux_net->ref); 2661 } 2662 2663 static inline void muxnet_put(struct gsm_mux_net *mux_net) 2664 { 2665 kref_put(&mux_net->ref, net_free); 2666 } 2667 2668 static int gsm_mux_net_start_xmit(struct sk_buff *skb, 2669 struct net_device *net) 2670 { 2671 struct gsm_mux_net *mux_net = netdev_priv(net); 2672 struct gsm_dlci *dlci = mux_net->dlci; 2673 muxnet_get(mux_net); 2674 2675 skb_queue_head(&dlci->skb_list, skb); 2676 net->stats.tx_packets++; 2677 net->stats.tx_bytes += skb->len; 2678 gsm_dlci_data_kick(dlci); 2679 /* And tell the kernel when the last transmit started. */ 2680 netif_trans_update(net); 2681 muxnet_put(mux_net); 2682 return NETDEV_TX_OK; 2683 } 2684 2685 /* called when a packet did not ack after watchdogtimeout */ 2686 static void gsm_mux_net_tx_timeout(struct net_device *net) 2687 { 2688 /* Tell syslog we are hosed. */ 2689 dev_dbg(&net->dev, "Tx timed out.\n"); 2690 2691 /* Update statistics */ 2692 net->stats.tx_errors++; 2693 } 2694 2695 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci, 2696 unsigned char *in_buf, int size) 2697 { 2698 struct net_device *net = dlci->net; 2699 struct sk_buff *skb; 2700 struct gsm_mux_net *mux_net = netdev_priv(net); 2701 muxnet_get(mux_net); 2702 2703 /* Allocate an sk_buff */ 2704 skb = dev_alloc_skb(size + NET_IP_ALIGN); 2705 if (!skb) { 2706 /* We got no receive buffer. */ 2707 net->stats.rx_dropped++; 2708 muxnet_put(mux_net); 2709 return; 2710 } 2711 skb_reserve(skb, NET_IP_ALIGN); 2712 skb_put_data(skb, in_buf, size); 2713 2714 skb->dev = net; 2715 skb->protocol = htons(ETH_P_IP); 2716 2717 /* Ship it off to the kernel */ 2718 netif_rx(skb); 2719 2720 /* update out statistics */ 2721 net->stats.rx_packets++; 2722 net->stats.rx_bytes += size; 2723 muxnet_put(mux_net); 2724 return; 2725 } 2726 2727 static void gsm_mux_net_init(struct net_device *net) 2728 { 2729 static const struct net_device_ops gsm_netdev_ops = { 2730 .ndo_open = gsm_mux_net_open, 2731 .ndo_stop = gsm_mux_net_close, 2732 .ndo_start_xmit = gsm_mux_net_start_xmit, 2733 .ndo_tx_timeout = gsm_mux_net_tx_timeout, 2734 }; 2735 2736 net->netdev_ops = &gsm_netdev_ops; 2737 2738 /* fill in the other fields */ 2739 net->watchdog_timeo = GSM_NET_TX_TIMEOUT; 2740 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 2741 net->type = ARPHRD_NONE; 2742 net->tx_queue_len = 10; 2743 } 2744 2745 2746 /* caller holds the dlci mutex */ 2747 static void gsm_destroy_network(struct gsm_dlci *dlci) 2748 { 2749 struct gsm_mux_net *mux_net; 2750 2751 pr_debug("destroy network interface"); 2752 if (!dlci->net) 2753 return; 2754 mux_net = netdev_priv(dlci->net); 2755 muxnet_put(mux_net); 2756 } 2757 2758 2759 /* caller holds the dlci mutex */ 2760 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc) 2761 { 2762 char *netname; 2763 int retval = 0; 2764 struct net_device *net; 2765 struct gsm_mux_net *mux_net; 2766 2767 if (!capable(CAP_NET_ADMIN)) 2768 return -EPERM; 2769 2770 /* Already in a non tty mode */ 2771 if (dlci->adaption > 2) 2772 return -EBUSY; 2773 2774 if (nc->protocol != htons(ETH_P_IP)) 2775 return -EPROTONOSUPPORT; 2776 2777 if (nc->adaption != 3 && nc->adaption != 4) 2778 return -EPROTONOSUPPORT; 2779 2780 pr_debug("create network interface"); 2781 2782 netname = "gsm%d"; 2783 if (nc->if_name[0] != '\0') 2784 netname = nc->if_name; 2785 net = alloc_netdev(sizeof(struct gsm_mux_net), netname, 2786 NET_NAME_UNKNOWN, gsm_mux_net_init); 2787 if (!net) { 2788 pr_err("alloc_netdev failed"); 2789 return -ENOMEM; 2790 } 2791 net->mtu = dlci->gsm->mtu; 2792 net->min_mtu = 8; 2793 net->max_mtu = dlci->gsm->mtu; 2794 mux_net = netdev_priv(net); 2795 mux_net->dlci = dlci; 2796 kref_init(&mux_net->ref); 2797 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */ 2798 2799 /* reconfigure dlci for network */ 2800 dlci->prev_adaption = dlci->adaption; 2801 dlci->prev_data = dlci->data; 2802 dlci->adaption = nc->adaption; 2803 dlci->data = gsm_mux_rx_netchar; 2804 dlci->net = net; 2805 2806 pr_debug("register netdev"); 2807 retval = register_netdev(net); 2808 if (retval) { 2809 pr_err("network register fail %d\n", retval); 2810 dlci_net_free(dlci); 2811 return retval; 2812 } 2813 return net->ifindex; /* return network index */ 2814 } 2815 2816 /* Line discipline for real tty */ 2817 static struct tty_ldisc_ops tty_ldisc_packet = { 2818 .owner = THIS_MODULE, 2819 .magic = TTY_LDISC_MAGIC, 2820 .name = "n_gsm", 2821 .open = gsmld_open, 2822 .close = gsmld_close, 2823 .flush_buffer = gsmld_flush_buffer, 2824 .read = gsmld_read, 2825 .write = gsmld_write, 2826 #ifdef CONFIG_COMPAT 2827 .compat_ioctl = gsmld_compat_ioctl, 2828 #endif 2829 .ioctl = gsmld_ioctl, 2830 .poll = gsmld_poll, 2831 .receive_buf = gsmld_receive_buf, 2832 .write_wakeup = gsmld_write_wakeup 2833 }; 2834 2835 /* 2836 * Virtual tty side 2837 */ 2838 2839 #define TX_SIZE 512 2840 2841 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) 2842 { 2843 u8 modembits[5]; 2844 struct gsm_control *ctrl; 2845 int len = 2; 2846 2847 if (brk) 2848 len++; 2849 2850 modembits[0] = len << 1 | EA; /* Data bytes */ 2851 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */ 2852 modembits[2] = gsm_encode_modem(dlci) << 1 | EA; 2853 if (brk) 2854 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */ 2855 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1); 2856 if (ctrl == NULL) 2857 return -ENOMEM; 2858 return gsm_control_wait(dlci->gsm, ctrl); 2859 } 2860 2861 static int gsm_carrier_raised(struct tty_port *port) 2862 { 2863 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2864 /* Not yet open so no carrier info */ 2865 if (dlci->state != DLCI_OPEN) 2866 return 0; 2867 if (debug & 2) 2868 return 1; 2869 return dlci->modem_rx & TIOCM_CD; 2870 } 2871 2872 static void gsm_dtr_rts(struct tty_port *port, int onoff) 2873 { 2874 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2875 unsigned int modem_tx = dlci->modem_tx; 2876 if (onoff) 2877 modem_tx |= TIOCM_DTR | TIOCM_RTS; 2878 else 2879 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); 2880 if (modem_tx != dlci->modem_tx) { 2881 dlci->modem_tx = modem_tx; 2882 gsmtty_modem_update(dlci, 0); 2883 } 2884 } 2885 2886 static const struct tty_port_operations gsm_port_ops = { 2887 .carrier_raised = gsm_carrier_raised, 2888 .dtr_rts = gsm_dtr_rts, 2889 .destruct = gsm_dlci_free, 2890 }; 2891 2892 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty) 2893 { 2894 struct gsm_mux *gsm; 2895 struct gsm_dlci *dlci; 2896 unsigned int line = tty->index; 2897 unsigned int mux = line >> 6; 2898 bool alloc = false; 2899 int ret; 2900 2901 line = line & 0x3F; 2902 2903 if (mux >= MAX_MUX) 2904 return -ENXIO; 2905 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */ 2906 if (gsm_mux[mux] == NULL) 2907 return -EUNATCH; 2908 if (line == 0 || line > 61) /* 62/63 reserved */ 2909 return -ECHRNG; 2910 gsm = gsm_mux[mux]; 2911 if (gsm->dead) 2912 return -EL2HLT; 2913 /* If DLCI 0 is not yet fully open return an error. 2914 This is ok from a locking 2915 perspective as we don't have to worry about this 2916 if DLCI0 is lost */ 2917 mutex_lock(&gsm->mutex); 2918 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) { 2919 mutex_unlock(&gsm->mutex); 2920 return -EL2NSYNC; 2921 } 2922 dlci = gsm->dlci[line]; 2923 if (dlci == NULL) { 2924 alloc = true; 2925 dlci = gsm_dlci_alloc(gsm, line); 2926 } 2927 if (dlci == NULL) { 2928 mutex_unlock(&gsm->mutex); 2929 return -ENOMEM; 2930 } 2931 ret = tty_port_install(&dlci->port, driver, tty); 2932 if (ret) { 2933 if (alloc) 2934 dlci_put(dlci); 2935 mutex_unlock(&gsm->mutex); 2936 return ret; 2937 } 2938 2939 dlci_get(dlci); 2940 dlci_get(gsm->dlci[0]); 2941 mux_get(gsm); 2942 tty->driver_data = dlci; 2943 mutex_unlock(&gsm->mutex); 2944 2945 return 0; 2946 } 2947 2948 static int gsmtty_open(struct tty_struct *tty, struct file *filp) 2949 { 2950 struct gsm_dlci *dlci = tty->driver_data; 2951 struct tty_port *port = &dlci->port; 2952 2953 port->count++; 2954 tty_port_tty_set(port, tty); 2955 2956 dlci->modem_rx = 0; 2957 /* We could in theory open and close before we wait - eg if we get 2958 a DM straight back. This is ok as that will have caused a hangup */ 2959 tty_port_set_initialized(port, 1); 2960 /* Start sending off SABM messages */ 2961 gsm_dlci_begin_open(dlci); 2962 /* And wait for virtual carrier */ 2963 return tty_port_block_til_ready(port, tty, filp); 2964 } 2965 2966 static void gsmtty_close(struct tty_struct *tty, struct file *filp) 2967 { 2968 struct gsm_dlci *dlci = tty->driver_data; 2969 2970 if (dlci == NULL) 2971 return; 2972 if (dlci->state == DLCI_CLOSED) 2973 return; 2974 mutex_lock(&dlci->mutex); 2975 gsm_destroy_network(dlci); 2976 mutex_unlock(&dlci->mutex); 2977 if (tty_port_close_start(&dlci->port, tty, filp) == 0) 2978 return; 2979 gsm_dlci_begin_close(dlci); 2980 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty)) 2981 tty_port_lower_dtr_rts(&dlci->port); 2982 tty_port_close_end(&dlci->port, tty); 2983 tty_port_tty_set(&dlci->port, NULL); 2984 return; 2985 } 2986 2987 static void gsmtty_hangup(struct tty_struct *tty) 2988 { 2989 struct gsm_dlci *dlci = tty->driver_data; 2990 if (dlci->state == DLCI_CLOSED) 2991 return; 2992 tty_port_hangup(&dlci->port); 2993 gsm_dlci_begin_close(dlci); 2994 } 2995 2996 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf, 2997 int len) 2998 { 2999 int sent; 3000 struct gsm_dlci *dlci = tty->driver_data; 3001 if (dlci->state == DLCI_CLOSED) 3002 return -EINVAL; 3003 /* Stuff the bytes into the fifo queue */ 3004 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock); 3005 /* Need to kick the channel */ 3006 gsm_dlci_data_kick(dlci); 3007 return sent; 3008 } 3009 3010 static int gsmtty_write_room(struct tty_struct *tty) 3011 { 3012 struct gsm_dlci *dlci = tty->driver_data; 3013 if (dlci->state == DLCI_CLOSED) 3014 return -EINVAL; 3015 return TX_SIZE - kfifo_len(dlci->fifo); 3016 } 3017 3018 static int gsmtty_chars_in_buffer(struct tty_struct *tty) 3019 { 3020 struct gsm_dlci *dlci = tty->driver_data; 3021 if (dlci->state == DLCI_CLOSED) 3022 return -EINVAL; 3023 return kfifo_len(dlci->fifo); 3024 } 3025 3026 static void gsmtty_flush_buffer(struct tty_struct *tty) 3027 { 3028 struct gsm_dlci *dlci = tty->driver_data; 3029 if (dlci->state == DLCI_CLOSED) 3030 return; 3031 /* Caution needed: If we implement reliable transport classes 3032 then the data being transmitted can't simply be junked once 3033 it has first hit the stack. Until then we can just blow it 3034 away */ 3035 kfifo_reset(dlci->fifo); 3036 /* Need to unhook this DLCI from the transmit queue logic */ 3037 } 3038 3039 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout) 3040 { 3041 /* The FIFO handles the queue so the kernel will do the right 3042 thing waiting on chars_in_buffer before calling us. No work 3043 to do here */ 3044 } 3045 3046 static int gsmtty_tiocmget(struct tty_struct *tty) 3047 { 3048 struct gsm_dlci *dlci = tty->driver_data; 3049 if (dlci->state == DLCI_CLOSED) 3050 return -EINVAL; 3051 return dlci->modem_rx; 3052 } 3053 3054 static int gsmtty_tiocmset(struct tty_struct *tty, 3055 unsigned int set, unsigned int clear) 3056 { 3057 struct gsm_dlci *dlci = tty->driver_data; 3058 unsigned int modem_tx = dlci->modem_tx; 3059 3060 if (dlci->state == DLCI_CLOSED) 3061 return -EINVAL; 3062 modem_tx &= ~clear; 3063 modem_tx |= set; 3064 3065 if (modem_tx != dlci->modem_tx) { 3066 dlci->modem_tx = modem_tx; 3067 return gsmtty_modem_update(dlci, 0); 3068 } 3069 return 0; 3070 } 3071 3072 3073 static int gsmtty_ioctl(struct tty_struct *tty, 3074 unsigned int cmd, unsigned long arg) 3075 { 3076 struct gsm_dlci *dlci = tty->driver_data; 3077 struct gsm_netconfig nc; 3078 int index; 3079 3080 if (dlci->state == DLCI_CLOSED) 3081 return -EINVAL; 3082 switch (cmd) { 3083 case GSMIOC_ENABLE_NET: 3084 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc))) 3085 return -EFAULT; 3086 nc.if_name[IFNAMSIZ-1] = '\0'; 3087 /* return net interface index or error code */ 3088 mutex_lock(&dlci->mutex); 3089 index = gsm_create_network(dlci, &nc); 3090 mutex_unlock(&dlci->mutex); 3091 if (copy_to_user((void __user *)arg, &nc, sizeof(nc))) 3092 return -EFAULT; 3093 return index; 3094 case GSMIOC_DISABLE_NET: 3095 if (!capable(CAP_NET_ADMIN)) 3096 return -EPERM; 3097 mutex_lock(&dlci->mutex); 3098 gsm_destroy_network(dlci); 3099 mutex_unlock(&dlci->mutex); 3100 return 0; 3101 default: 3102 return -ENOIOCTLCMD; 3103 } 3104 } 3105 3106 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old) 3107 { 3108 struct gsm_dlci *dlci = tty->driver_data; 3109 if (dlci->state == DLCI_CLOSED) 3110 return; 3111 /* For the moment its fixed. In actual fact the speed information 3112 for the virtual channel can be propogated in both directions by 3113 the RPN control message. This however rapidly gets nasty as we 3114 then have to remap modem signals each way according to whether 3115 our virtual cable is null modem etc .. */ 3116 tty_termios_copy_hw(&tty->termios, old); 3117 } 3118 3119 static void gsmtty_throttle(struct tty_struct *tty) 3120 { 3121 struct gsm_dlci *dlci = tty->driver_data; 3122 if (dlci->state == DLCI_CLOSED) 3123 return; 3124 if (C_CRTSCTS(tty)) 3125 dlci->modem_tx &= ~TIOCM_DTR; 3126 dlci->throttled = 1; 3127 /* Send an MSC with DTR cleared */ 3128 gsmtty_modem_update(dlci, 0); 3129 } 3130 3131 static void gsmtty_unthrottle(struct tty_struct *tty) 3132 { 3133 struct gsm_dlci *dlci = tty->driver_data; 3134 if (dlci->state == DLCI_CLOSED) 3135 return; 3136 if (C_CRTSCTS(tty)) 3137 dlci->modem_tx |= TIOCM_DTR; 3138 dlci->throttled = 0; 3139 /* Send an MSC with DTR set */ 3140 gsmtty_modem_update(dlci, 0); 3141 } 3142 3143 static int gsmtty_break_ctl(struct tty_struct *tty, int state) 3144 { 3145 struct gsm_dlci *dlci = tty->driver_data; 3146 int encode = 0; /* Off */ 3147 if (dlci->state == DLCI_CLOSED) 3148 return -EINVAL; 3149 3150 if (state == -1) /* "On indefinitely" - we can't encode this 3151 properly */ 3152 encode = 0x0F; 3153 else if (state > 0) { 3154 encode = state / 200; /* mS to encoding */ 3155 if (encode > 0x0F) 3156 encode = 0x0F; /* Best effort */ 3157 } 3158 return gsmtty_modem_update(dlci, encode); 3159 } 3160 3161 static void gsmtty_cleanup(struct tty_struct *tty) 3162 { 3163 struct gsm_dlci *dlci = tty->driver_data; 3164 struct gsm_mux *gsm = dlci->gsm; 3165 3166 dlci_put(dlci); 3167 dlci_put(gsm->dlci[0]); 3168 mux_put(gsm); 3169 } 3170 3171 /* Virtual ttys for the demux */ 3172 static const struct tty_operations gsmtty_ops = { 3173 .install = gsmtty_install, 3174 .open = gsmtty_open, 3175 .close = gsmtty_close, 3176 .write = gsmtty_write, 3177 .write_room = gsmtty_write_room, 3178 .chars_in_buffer = gsmtty_chars_in_buffer, 3179 .flush_buffer = gsmtty_flush_buffer, 3180 .ioctl = gsmtty_ioctl, 3181 .throttle = gsmtty_throttle, 3182 .unthrottle = gsmtty_unthrottle, 3183 .set_termios = gsmtty_set_termios, 3184 .hangup = gsmtty_hangup, 3185 .wait_until_sent = gsmtty_wait_until_sent, 3186 .tiocmget = gsmtty_tiocmget, 3187 .tiocmset = gsmtty_tiocmset, 3188 .break_ctl = gsmtty_break_ctl, 3189 .cleanup = gsmtty_cleanup, 3190 }; 3191 3192 3193 3194 static int __init gsm_init(void) 3195 { 3196 /* Fill in our line protocol discipline, and register it */ 3197 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet); 3198 if (status != 0) { 3199 pr_err("n_gsm: can't register line discipline (err = %d)\n", 3200 status); 3201 return status; 3202 } 3203 3204 gsm_tty_driver = alloc_tty_driver(256); 3205 if (!gsm_tty_driver) { 3206 tty_unregister_ldisc(N_GSM0710); 3207 pr_err("gsm_init: tty allocation failed.\n"); 3208 return -EINVAL; 3209 } 3210 gsm_tty_driver->driver_name = "gsmtty"; 3211 gsm_tty_driver->name = "gsmtty"; 3212 gsm_tty_driver->major = 0; /* Dynamic */ 3213 gsm_tty_driver->minor_start = 0; 3214 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; 3215 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL; 3216 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV 3217 | TTY_DRIVER_HARDWARE_BREAK; 3218 gsm_tty_driver->init_termios = tty_std_termios; 3219 /* Fixme */ 3220 gsm_tty_driver->init_termios.c_lflag &= ~ECHO; 3221 tty_set_operations(gsm_tty_driver, &gsmtty_ops); 3222 3223 spin_lock_init(&gsm_mux_lock); 3224 3225 if (tty_register_driver(gsm_tty_driver)) { 3226 put_tty_driver(gsm_tty_driver); 3227 tty_unregister_ldisc(N_GSM0710); 3228 pr_err("gsm_init: tty registration failed.\n"); 3229 return -EBUSY; 3230 } 3231 pr_debug("gsm_init: loaded as %d,%d.\n", 3232 gsm_tty_driver->major, gsm_tty_driver->minor_start); 3233 return 0; 3234 } 3235 3236 static void __exit gsm_exit(void) 3237 { 3238 int status = tty_unregister_ldisc(N_GSM0710); 3239 if (status != 0) 3240 pr_err("n_gsm: can't unregister line discipline (err = %d)\n", 3241 status); 3242 tty_unregister_driver(gsm_tty_driver); 3243 put_tty_driver(gsm_tty_driver); 3244 } 3245 3246 module_init(gsm_init); 3247 module_exit(gsm_exit); 3248 3249 3250 MODULE_LICENSE("GPL"); 3251 MODULE_ALIAS_LDISC(N_GSM0710); 3252