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