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