1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * n_gsm.c GSM 0710 tty multiplexor 4 * Copyright (c) 2009/10 Intel Corporation 5 * 6 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE * 7 * 8 * TO DO: 9 * Mostly done: ioctls for setting modes/timing 10 * Partly done: hooks so you can pull off frames to non tty devs 11 * Restart DLCI 0 when it closes ? 12 * Improve the tx engine 13 * Resolve tx side locking by adding a queue_head and routing 14 * all control traffic via it 15 * General tidy/document 16 * Review the locking/move to refcounts more (mux now moved to an 17 * alloc/free model ready) 18 * Use newest tty open/close port helpers and install hooks 19 * What to do about power functions ? 20 * Termios setting and negotiation 21 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets 22 * 23 */ 24 25 #include <linux/types.h> 26 #include <linux/major.h> 27 #include <linux/errno.h> 28 #include <linux/signal.h> 29 #include <linux/fcntl.h> 30 #include <linux/sched/signal.h> 31 #include <linux/interrupt.h> 32 #include <linux/tty.h> 33 #include <linux/ctype.h> 34 #include <linux/mm.h> 35 #include <linux/string.h> 36 #include <linux/slab.h> 37 #include <linux/poll.h> 38 #include <linux/bitops.h> 39 #include <linux/file.h> 40 #include <linux/uaccess.h> 41 #include <linux/module.h> 42 #include <linux/timer.h> 43 #include <linux/tty_flip.h> 44 #include <linux/tty_driver.h> 45 #include <linux/serial.h> 46 #include <linux/kfifo.h> 47 #include <linux/skbuff.h> 48 #include <net/arp.h> 49 #include <linux/ip.h> 50 #include <linux/netdevice.h> 51 #include <linux/etherdevice.h> 52 #include <linux/gsmmux.h> 53 54 static int debug; 55 module_param(debug, int, 0600); 56 57 /* Defaults: these are from the specification */ 58 59 #define T1 10 /* 100mS */ 60 #define T2 34 /* 333mS */ 61 #define N2 3 /* Retry 3 times */ 62 63 /* Use long timers for testing at low speed with debug on */ 64 #ifdef DEBUG_TIMING 65 #define T1 100 66 #define T2 200 67 #endif 68 69 /* 70 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte 71 * limits so this is plenty 72 */ 73 #define MAX_MRU 1500 74 #define MAX_MTU 1500 75 #define GSM_NET_TX_TIMEOUT (HZ*10) 76 77 /** 78 * struct gsm_mux_net - network interface 79 * @struct gsm_dlci* dlci 80 * 81 * Created when net interface is initialized. 82 **/ 83 struct gsm_mux_net { 84 struct kref ref; 85 struct gsm_dlci *dlci; 86 }; 87 88 /* 89 * Each block of data we have queued to go out is in the form of 90 * a gsm_msg which holds everything we need in a link layer independent 91 * format 92 */ 93 94 struct gsm_msg { 95 struct list_head list; 96 u8 addr; /* DLCI address + flags */ 97 u8 ctrl; /* Control byte + flags */ 98 unsigned int len; /* Length of data block (can be zero) */ 99 unsigned char *data; /* Points into buffer but not at the start */ 100 unsigned char buffer[0]; 101 }; 102 103 /* 104 * Each active data link has a gsm_dlci structure associated which ties 105 * the link layer to an optional tty (if the tty side is open). To avoid 106 * complexity right now these are only ever freed up when the mux is 107 * shut down. 108 * 109 * At the moment we don't free DLCI objects until the mux is torn down 110 * this avoid object life time issues but might be worth review later. 111 */ 112 113 struct gsm_dlci { 114 struct gsm_mux *gsm; 115 int addr; 116 int state; 117 #define DLCI_CLOSED 0 118 #define DLCI_OPENING 1 /* Sending SABM not seen UA */ 119 #define DLCI_OPEN 2 /* SABM/UA complete */ 120 #define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */ 121 struct mutex mutex; 122 123 /* Link layer */ 124 spinlock_t lock; /* Protects the internal state */ 125 struct timer_list t1; /* Retransmit timer for SABM and UA */ 126 int retries; 127 /* Uplink tty if active */ 128 struct tty_port port; /* The tty bound to this DLCI if there is one */ 129 struct kfifo *fifo; /* Queue fifo for the DLCI */ 130 struct kfifo _fifo; /* For new fifo API porting only */ 131 int adaption; /* Adaption layer in use */ 132 int prev_adaption; 133 u32 modem_rx; /* Our incoming virtual modem lines */ 134 u32 modem_tx; /* Our outgoing modem lines */ 135 int dead; /* Refuse re-open */ 136 /* Flow control */ 137 int throttled; /* Private copy of throttle state */ 138 int constipated; /* Throttle status for outgoing */ 139 /* Packetised I/O */ 140 struct sk_buff *skb; /* Frame being sent */ 141 struct sk_buff_head skb_list; /* Queued frames */ 142 /* Data handling callback */ 143 void (*data)(struct gsm_dlci *dlci, u8 *data, int len); 144 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len); 145 struct net_device *net; /* network interface, if created */ 146 }; 147 148 /* DLCI 0, 62/63 are special or reserved see gsmtty_open */ 149 150 #define NUM_DLCI 64 151 152 /* 153 * DLCI 0 is used to pass control blocks out of band of the data 154 * flow (and with a higher link priority). One command can be outstanding 155 * at a time and we use this structure to manage them. They are created 156 * and destroyed by the user context, and updated by the receive paths 157 * and timers 158 */ 159 160 struct gsm_control { 161 u8 cmd; /* Command we are issuing */ 162 u8 *data; /* Data for the command in case we retransmit */ 163 int len; /* Length of block for retransmission */ 164 int done; /* Done flag */ 165 int error; /* Error if any */ 166 }; 167 168 /* 169 * Each GSM mux we have is represented by this structure. If we are 170 * operating as an ldisc then we use this structure as our ldisc 171 * state. We need to sort out lifetimes and locking with respect 172 * to the gsm mux array. For now we don't free DLCI objects that 173 * have been instantiated until the mux itself is terminated. 174 * 175 * To consider further: tty open versus mux shutdown. 176 */ 177 178 struct gsm_mux { 179 struct tty_struct *tty; /* The tty our ldisc is bound to */ 180 spinlock_t lock; 181 struct mutex mutex; 182 unsigned int num; 183 struct kref ref; 184 185 /* Events on the GSM channel */ 186 wait_queue_head_t event; 187 188 /* Bits for GSM mode decoding */ 189 190 /* Framing Layer */ 191 unsigned char *buf; 192 int state; 193 #define GSM_SEARCH 0 194 #define GSM_START 1 195 #define GSM_ADDRESS 2 196 #define GSM_CONTROL 3 197 #define GSM_LEN 4 198 #define GSM_DATA 5 199 #define GSM_FCS 6 200 #define GSM_OVERRUN 7 201 #define GSM_LEN0 8 202 #define GSM_LEN1 9 203 #define GSM_SSOF 10 204 unsigned int len; 205 unsigned int address; 206 unsigned int count; 207 int escape; 208 int encoding; 209 u8 control; 210 u8 fcs; 211 u8 received_fcs; 212 u8 *txframe; /* TX framing buffer */ 213 214 /* Methods for the receiver side */ 215 void (*receive)(struct gsm_mux *gsm, u8 ch); 216 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag); 217 /* And transmit side */ 218 int (*output)(struct gsm_mux *mux, u8 *data, int len); 219 220 /* Link Layer */ 221 unsigned int mru; 222 unsigned int mtu; 223 int initiator; /* Did we initiate connection */ 224 int dead; /* Has the mux been shut down */ 225 struct gsm_dlci *dlci[NUM_DLCI]; 226 int constipated; /* Asked by remote to shut up */ 227 228 spinlock_t tx_lock; 229 unsigned int tx_bytes; /* TX data outstanding */ 230 #define TX_THRESH_HI 8192 231 #define TX_THRESH_LO 2048 232 struct list_head tx_list; /* Pending data packets */ 233 234 /* Control messages */ 235 struct timer_list t2_timer; /* Retransmit timer for commands */ 236 int cretries; /* Command retry counter */ 237 struct gsm_control *pending_cmd;/* Our current pending command */ 238 spinlock_t control_lock; /* Protects the pending command */ 239 240 /* Configuration */ 241 int adaption; /* 1 or 2 supported */ 242 u8 ftype; /* UI or UIH */ 243 int t1, t2; /* Timers in 1/100th of a sec */ 244 int n2; /* Retry count */ 245 246 /* Statistics (not currently exposed) */ 247 unsigned long bad_fcs; 248 unsigned long malformed; 249 unsigned long io_error; 250 unsigned long bad_size; 251 unsigned long unsupported; 252 }; 253 254 255 /* 256 * Mux objects - needed so that we can translate a tty index into the 257 * relevant mux and DLCI. 258 */ 259 260 #define MAX_MUX 4 /* 256 minors */ 261 static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */ 262 static spinlock_t gsm_mux_lock; 263 264 static struct tty_driver *gsm_tty_driver; 265 266 /* 267 * This section of the driver logic implements the GSM encodings 268 * both the basic and the 'advanced'. Reliable transport is not 269 * supported. 270 */ 271 272 #define CR 0x02 273 #define EA 0x01 274 #define PF 0x10 275 276 /* I is special: the rest are ..*/ 277 #define RR 0x01 278 #define UI 0x03 279 #define RNR 0x05 280 #define REJ 0x09 281 #define DM 0x0F 282 #define SABM 0x2F 283 #define DISC 0x43 284 #define UA 0x63 285 #define UIH 0xEF 286 287 /* Channel commands */ 288 #define CMD_NSC 0x09 289 #define CMD_TEST 0x11 290 #define CMD_PSC 0x21 291 #define CMD_RLS 0x29 292 #define CMD_FCOFF 0x31 293 #define CMD_PN 0x41 294 #define CMD_RPN 0x49 295 #define CMD_FCON 0x51 296 #define CMD_CLD 0x61 297 #define CMD_SNC 0x69 298 #define CMD_MSC 0x71 299 300 /* Virtual modem bits */ 301 #define MDM_FC 0x01 302 #define MDM_RTC 0x02 303 #define MDM_RTR 0x04 304 #define MDM_IC 0x20 305 #define MDM_DV 0x40 306 307 #define GSM0_SOF 0xF9 308 #define GSM1_SOF 0x7E 309 #define GSM1_ESCAPE 0x7D 310 #define GSM1_ESCAPE_BITS 0x20 311 #define XON 0x11 312 #define XOFF 0x13 313 314 static const struct tty_port_operations gsm_port_ops; 315 316 /* 317 * CRC table for GSM 0710 318 */ 319 320 static const u8 gsm_fcs8[256] = { 321 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75, 322 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B, 323 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69, 324 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67, 325 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D, 326 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43, 327 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51, 328 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F, 329 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05, 330 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B, 331 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19, 332 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17, 333 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D, 334 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33, 335 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21, 336 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F, 337 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95, 338 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B, 339 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89, 340 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87, 341 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD, 342 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3, 343 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1, 344 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF, 345 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5, 346 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB, 347 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9, 348 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7, 349 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD, 350 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3, 351 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1, 352 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF 353 }; 354 355 #define INIT_FCS 0xFF 356 #define GOOD_FCS 0xCF 357 358 /** 359 * gsm_fcs_add - update FCS 360 * @fcs: Current FCS 361 * @c: Next data 362 * 363 * Update the FCS to include c. Uses the algorithm in the specification 364 * notes. 365 */ 366 367 static inline u8 gsm_fcs_add(u8 fcs, u8 c) 368 { 369 return gsm_fcs8[fcs ^ c]; 370 } 371 372 /** 373 * gsm_fcs_add_block - update FCS for a block 374 * @fcs: Current FCS 375 * @c: buffer of data 376 * @len: length of buffer 377 * 378 * Update the FCS to include c. Uses the algorithm in the specification 379 * notes. 380 */ 381 382 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len) 383 { 384 while (len--) 385 fcs = gsm_fcs8[fcs ^ *c++]; 386 return fcs; 387 } 388 389 /** 390 * gsm_read_ea - read a byte into an EA 391 * @val: variable holding value 392 * c: byte going into the EA 393 * 394 * Processes one byte of an EA. Updates the passed variable 395 * and returns 1 if the EA is now completely read 396 */ 397 398 static int gsm_read_ea(unsigned int *val, u8 c) 399 { 400 /* Add the next 7 bits into the value */ 401 *val <<= 7; 402 *val |= c >> 1; 403 /* Was this the last byte of the EA 1 = yes*/ 404 return c & EA; 405 } 406 407 /** 408 * gsm_encode_modem - encode modem data bits 409 * @dlci: DLCI to encode from 410 * 411 * Returns the correct GSM encoded modem status bits (6 bit field) for 412 * the current status of the DLCI and attached tty object 413 */ 414 415 static u8 gsm_encode_modem(const struct gsm_dlci *dlci) 416 { 417 u8 modembits = 0; 418 /* FC is true flow control not modem bits */ 419 if (dlci->throttled) 420 modembits |= MDM_FC; 421 if (dlci->modem_tx & TIOCM_DTR) 422 modembits |= MDM_RTC; 423 if (dlci->modem_tx & TIOCM_RTS) 424 modembits |= MDM_RTR; 425 if (dlci->modem_tx & TIOCM_RI) 426 modembits |= MDM_IC; 427 if (dlci->modem_tx & TIOCM_CD) 428 modembits |= MDM_DV; 429 return modembits; 430 } 431 432 /** 433 * gsm_print_packet - display a frame for debug 434 * @hdr: header to print before decode 435 * @addr: address EA from the frame 436 * @cr: C/R bit from the frame 437 * @control: control including PF bit 438 * @data: following data bytes 439 * @dlen: length of data 440 * 441 * Displays a packet in human readable format for debugging purposes. The 442 * style is based on amateur radio LAP-B dump display. 443 */ 444 445 static void gsm_print_packet(const char *hdr, int addr, int cr, 446 u8 control, const u8 *data, int dlen) 447 { 448 if (!(debug & 1)) 449 return; 450 451 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]); 452 453 switch (control & ~PF) { 454 case SABM: 455 pr_cont("SABM"); 456 break; 457 case UA: 458 pr_cont("UA"); 459 break; 460 case DISC: 461 pr_cont("DISC"); 462 break; 463 case DM: 464 pr_cont("DM"); 465 break; 466 case UI: 467 pr_cont("UI"); 468 break; 469 case UIH: 470 pr_cont("UIH"); 471 break; 472 default: 473 if (!(control & 0x01)) { 474 pr_cont("I N(S)%d N(R)%d", 475 (control & 0x0E) >> 1, (control & 0xE0) >> 5); 476 } else switch (control & 0x0F) { 477 case RR: 478 pr_cont("RR(%d)", (control & 0xE0) >> 5); 479 break; 480 case RNR: 481 pr_cont("RNR(%d)", (control & 0xE0) >> 5); 482 break; 483 case REJ: 484 pr_cont("REJ(%d)", (control & 0xE0) >> 5); 485 break; 486 default: 487 pr_cont("[%02X]", control); 488 } 489 } 490 491 if (control & PF) 492 pr_cont("(P)"); 493 else 494 pr_cont("(F)"); 495 496 if (dlen) { 497 int ct = 0; 498 while (dlen--) { 499 if (ct % 8 == 0) { 500 pr_cont("\n"); 501 pr_debug(" "); 502 } 503 pr_cont("%02X ", *data++); 504 ct++; 505 } 506 } 507 pr_cont("\n"); 508 } 509 510 511 /* 512 * Link level transmission side 513 */ 514 515 /** 516 * gsm_stuff_packet - bytestuff a packet 517 * @ibuf: input 518 * @obuf: output 519 * @len: length of input 520 * 521 * Expand a buffer by bytestuffing it. The worst case size change 522 * is doubling and the caller is responsible for handing out 523 * suitable sized buffers. 524 */ 525 526 static int gsm_stuff_frame(const u8 *input, u8 *output, int len) 527 { 528 int olen = 0; 529 while (len--) { 530 if (*input == GSM1_SOF || *input == GSM1_ESCAPE 531 || *input == XON || *input == XOFF) { 532 *output++ = GSM1_ESCAPE; 533 *output++ = *input++ ^ GSM1_ESCAPE_BITS; 534 olen++; 535 } else 536 *output++ = *input++; 537 olen++; 538 } 539 return olen; 540 } 541 542 /** 543 * gsm_send - send a control frame 544 * @gsm: our GSM mux 545 * @addr: address for control frame 546 * @cr: command/response bit 547 * @control: control byte including PF bit 548 * 549 * Format up and transmit a control frame. These do not go via the 550 * queueing logic as they should be transmitted ahead of data when 551 * they are needed. 552 * 553 * FIXME: Lock versus data TX path 554 */ 555 556 static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control) 557 { 558 int len; 559 u8 cbuf[10]; 560 u8 ibuf[3]; 561 562 switch (gsm->encoding) { 563 case 0: 564 cbuf[0] = GSM0_SOF; 565 cbuf[1] = (addr << 2) | (cr << 1) | EA; 566 cbuf[2] = control; 567 cbuf[3] = EA; /* Length of data = 0 */ 568 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3); 569 cbuf[5] = GSM0_SOF; 570 len = 6; 571 break; 572 case 1: 573 case 2: 574 /* Control frame + packing (but not frame stuffing) in mode 1 */ 575 ibuf[0] = (addr << 2) | (cr << 1) | EA; 576 ibuf[1] = control; 577 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2); 578 /* Stuffing may double the size worst case */ 579 len = gsm_stuff_frame(ibuf, cbuf + 1, 3); 580 /* Now add the SOF markers */ 581 cbuf[0] = GSM1_SOF; 582 cbuf[len + 1] = GSM1_SOF; 583 /* FIXME: we can omit the lead one in many cases */ 584 len += 2; 585 break; 586 default: 587 WARN_ON(1); 588 return; 589 } 590 gsm->output(gsm, cbuf, len); 591 gsm_print_packet("-->", addr, cr, control, NULL, 0); 592 } 593 594 /** 595 * gsm_response - send a control response 596 * @gsm: our GSM mux 597 * @addr: address for control frame 598 * @control: control byte including PF bit 599 * 600 * Format up and transmit a link level response frame. 601 */ 602 603 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control) 604 { 605 gsm_send(gsm, addr, 0, control); 606 } 607 608 /** 609 * gsm_command - send a control command 610 * @gsm: our GSM mux 611 * @addr: address for control frame 612 * @control: control byte including PF bit 613 * 614 * Format up and transmit a link level command frame. 615 */ 616 617 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control) 618 { 619 gsm_send(gsm, addr, 1, control); 620 } 621 622 /* Data transmission */ 623 624 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */ 625 626 /** 627 * gsm_data_alloc - allocate data frame 628 * @gsm: GSM mux 629 * @addr: DLCI address 630 * @len: length excluding header and FCS 631 * @ctrl: control byte 632 * 633 * Allocate a new data buffer for sending frames with data. Space is left 634 * at the front for header bytes but that is treated as an implementation 635 * detail and not for the high level code to use 636 */ 637 638 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len, 639 u8 ctrl) 640 { 641 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN, 642 GFP_ATOMIC); 643 if (m == NULL) 644 return NULL; 645 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */ 646 m->len = len; 647 m->addr = addr; 648 m->ctrl = ctrl; 649 INIT_LIST_HEAD(&m->list); 650 return m; 651 } 652 653 /** 654 * gsm_data_kick - poke the queue 655 * @gsm: GSM Mux 656 * 657 * The tty device has called us to indicate that room has appeared in 658 * the transmit queue. Ram more data into the pipe if we have any 659 * If we have been flow-stopped by a CMD_FCOFF, then we can only 660 * send messages on DLCI0 until CMD_FCON 661 * 662 * FIXME: lock against link layer control transmissions 663 */ 664 665 static void gsm_data_kick(struct gsm_mux *gsm) 666 { 667 struct gsm_msg *msg, *nmsg; 668 int len; 669 int skip_sof = 0; 670 671 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) { 672 if (gsm->constipated && msg->addr) 673 continue; 674 if (gsm->encoding != 0) { 675 gsm->txframe[0] = GSM1_SOF; 676 len = gsm_stuff_frame(msg->data, 677 gsm->txframe + 1, msg->len); 678 gsm->txframe[len + 1] = GSM1_SOF; 679 len += 2; 680 } else { 681 gsm->txframe[0] = GSM0_SOF; 682 memcpy(gsm->txframe + 1 , msg->data, msg->len); 683 gsm->txframe[msg->len + 1] = GSM0_SOF; 684 len = msg->len + 2; 685 } 686 687 if (debug & 4) 688 print_hex_dump_bytes("gsm_data_kick: ", 689 DUMP_PREFIX_OFFSET, 690 gsm->txframe, len); 691 692 if (gsm->output(gsm, gsm->txframe + skip_sof, 693 len - skip_sof) < 0) 694 break; 695 /* FIXME: Can eliminate one SOF in many more cases */ 696 gsm->tx_bytes -= msg->len; 697 /* For a burst of frames skip the extra SOF within the 698 burst */ 699 skip_sof = 1; 700 701 list_del(&msg->list); 702 kfree(msg); 703 } 704 } 705 706 /** 707 * __gsm_data_queue - queue a UI or UIH frame 708 * @dlci: DLCI sending the data 709 * @msg: message queued 710 * 711 * Add data to the transmit queue and try and get stuff moving 712 * out of the mux tty if not already doing so. The Caller must hold 713 * the gsm tx lock. 714 */ 715 716 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) 717 { 718 struct gsm_mux *gsm = dlci->gsm; 719 u8 *dp = msg->data; 720 u8 *fcs = dp + msg->len; 721 722 /* Fill in the header */ 723 if (gsm->encoding == 0) { 724 if (msg->len < 128) 725 *--dp = (msg->len << 1) | EA; 726 else { 727 *--dp = (msg->len >> 7); /* bits 7 - 15 */ 728 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */ 729 } 730 } 731 732 *--dp = msg->ctrl; 733 if (gsm->initiator) 734 *--dp = (msg->addr << 2) | 2 | EA; 735 else 736 *--dp = (msg->addr << 2) | EA; 737 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp); 738 /* Ugly protocol layering violation */ 739 if (msg->ctrl == UI || msg->ctrl == (UI|PF)) 740 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len); 741 *fcs = 0xFF - *fcs; 742 743 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl, 744 msg->data, msg->len); 745 746 /* Move the header back and adjust the length, also allow for the FCS 747 now tacked on the end */ 748 msg->len += (msg->data - dp) + 1; 749 msg->data = dp; 750 751 /* Add to the actual output queue */ 752 list_add_tail(&msg->list, &gsm->tx_list); 753 gsm->tx_bytes += msg->len; 754 gsm_data_kick(gsm); 755 } 756 757 /** 758 * gsm_data_queue - queue a UI or UIH frame 759 * @dlci: DLCI sending the data 760 * @msg: message queued 761 * 762 * Add data to the transmit queue and try and get stuff moving 763 * out of the mux tty if not already doing so. Take the 764 * the gsm tx lock and dlci lock. 765 */ 766 767 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) 768 { 769 unsigned long flags; 770 spin_lock_irqsave(&dlci->gsm->tx_lock, flags); 771 __gsm_data_queue(dlci, msg); 772 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); 773 } 774 775 /** 776 * gsm_dlci_data_output - try and push data out of a DLCI 777 * @gsm: mux 778 * @dlci: the DLCI to pull data from 779 * 780 * Pull data from a DLCI and send it into the transmit queue if there 781 * is data. Keep to the MRU of the mux. This path handles the usual tty 782 * interface which is a byte stream with optional modem data. 783 * 784 * Caller must hold the tx_lock of the mux. 785 */ 786 787 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci) 788 { 789 struct gsm_msg *msg; 790 u8 *dp; 791 int len, total_size, size; 792 int h = dlci->adaption - 1; 793 794 total_size = 0; 795 while (1) { 796 len = kfifo_len(dlci->fifo); 797 if (len == 0) 798 return total_size; 799 800 /* MTU/MRU count only the data bits */ 801 if (len > gsm->mtu) 802 len = gsm->mtu; 803 804 size = len + h; 805 806 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); 807 /* FIXME: need a timer or something to kick this so it can't 808 get stuck with no work outstanding and no buffer free */ 809 if (msg == NULL) 810 return -ENOMEM; 811 dp = msg->data; 812 switch (dlci->adaption) { 813 case 1: /* Unstructured */ 814 break; 815 case 2: /* Unstructed with modem bits. 816 Always one byte as we never send inline break data */ 817 *dp++ = gsm_encode_modem(dlci); 818 break; 819 } 820 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len); 821 __gsm_data_queue(dlci, msg); 822 total_size += size; 823 } 824 /* Bytes of data we used up */ 825 return total_size; 826 } 827 828 /** 829 * gsm_dlci_data_output_framed - try and push data out of a DLCI 830 * @gsm: mux 831 * @dlci: the DLCI to pull data from 832 * 833 * Pull data from a DLCI and send it into the transmit queue if there 834 * is data. Keep to the MRU of the mux. This path handles framed data 835 * queued as skbuffs to the DLCI. 836 * 837 * Caller must hold the tx_lock of the mux. 838 */ 839 840 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, 841 struct gsm_dlci *dlci) 842 { 843 struct gsm_msg *msg; 844 u8 *dp; 845 int len, size; 846 int last = 0, first = 0; 847 int overhead = 0; 848 849 /* One byte per frame is used for B/F flags */ 850 if (dlci->adaption == 4) 851 overhead = 1; 852 853 /* dlci->skb is locked by tx_lock */ 854 if (dlci->skb == NULL) { 855 dlci->skb = skb_dequeue_tail(&dlci->skb_list); 856 if (dlci->skb == NULL) 857 return 0; 858 first = 1; 859 } 860 len = dlci->skb->len + overhead; 861 862 /* MTU/MRU count only the data bits */ 863 if (len > gsm->mtu) { 864 if (dlci->adaption == 3) { 865 /* Over long frame, bin it */ 866 dev_kfree_skb_any(dlci->skb); 867 dlci->skb = NULL; 868 return 0; 869 } 870 len = gsm->mtu; 871 } else 872 last = 1; 873 874 size = len + overhead; 875 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); 876 877 /* FIXME: need a timer or something to kick this so it can't 878 get stuck with no work outstanding and no buffer free */ 879 if (msg == NULL) { 880 skb_queue_tail(&dlci->skb_list, dlci->skb); 881 dlci->skb = NULL; 882 return -ENOMEM; 883 } 884 dp = msg->data; 885 886 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */ 887 /* Flag byte to carry the start/end info */ 888 *dp++ = last << 7 | first << 6 | 1; /* EA */ 889 len--; 890 } 891 memcpy(dp, dlci->skb->data, len); 892 skb_pull(dlci->skb, len); 893 __gsm_data_queue(dlci, msg); 894 if (last) { 895 dev_kfree_skb_any(dlci->skb); 896 dlci->skb = NULL; 897 } 898 return size; 899 } 900 901 /** 902 * gsm_dlci_data_sweep - look for data to send 903 * @gsm: the GSM mux 904 * 905 * Sweep the GSM mux channels in priority order looking for ones with 906 * data to send. We could do with optimising this scan a bit. We aim 907 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit 908 * TX_THRESH_LO we get called again 909 * 910 * FIXME: We should round robin between groups and in theory you can 911 * renegotiate DLCI priorities with optional stuff. Needs optimising. 912 */ 913 914 static void gsm_dlci_data_sweep(struct gsm_mux *gsm) 915 { 916 int len; 917 /* Priority ordering: We should do priority with RR of the groups */ 918 int i = 1; 919 920 while (i < NUM_DLCI) { 921 struct gsm_dlci *dlci; 922 923 if (gsm->tx_bytes > TX_THRESH_HI) 924 break; 925 dlci = gsm->dlci[i]; 926 if (dlci == NULL || dlci->constipated) { 927 i++; 928 continue; 929 } 930 if (dlci->adaption < 3 && !dlci->net) 931 len = gsm_dlci_data_output(gsm, dlci); 932 else 933 len = gsm_dlci_data_output_framed(gsm, dlci); 934 if (len < 0) 935 break; 936 /* DLCI empty - try the next */ 937 if (len == 0) 938 i++; 939 } 940 } 941 942 /** 943 * gsm_dlci_data_kick - transmit if possible 944 * @dlci: DLCI to kick 945 * 946 * Transmit data from this DLCI if the queue is empty. We can't rely on 947 * a tty wakeup except when we filled the pipe so we need to fire off 948 * new data ourselves in other cases. 949 */ 950 951 static void gsm_dlci_data_kick(struct gsm_dlci *dlci) 952 { 953 unsigned long flags; 954 int sweep; 955 956 if (dlci->constipated) 957 return; 958 959 spin_lock_irqsave(&dlci->gsm->tx_lock, flags); 960 /* If we have nothing running then we need to fire up */ 961 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO); 962 if (dlci->gsm->tx_bytes == 0) { 963 if (dlci->net) 964 gsm_dlci_data_output_framed(dlci->gsm, dlci); 965 else 966 gsm_dlci_data_output(dlci->gsm, dlci); 967 } 968 if (sweep) 969 gsm_dlci_data_sweep(dlci->gsm); 970 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); 971 } 972 973 /* 974 * Control message processing 975 */ 976 977 978 /** 979 * gsm_control_reply - send a response frame to a control 980 * @gsm: gsm channel 981 * @cmd: the command to use 982 * @data: data to follow encoded info 983 * @dlen: length of data 984 * 985 * Encode up and queue a UI/UIH frame containing our response. 986 */ 987 988 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data, 989 int dlen) 990 { 991 struct gsm_msg *msg; 992 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype); 993 if (msg == NULL) 994 return; 995 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */ 996 msg->data[1] = (dlen << 1) | EA; 997 memcpy(msg->data + 2, data, dlen); 998 gsm_data_queue(gsm->dlci[0], msg); 999 } 1000 1001 /** 1002 * gsm_process_modem - process received modem status 1003 * @tty: virtual tty bound to the DLCI 1004 * @dlci: DLCI to affect 1005 * @modem: modem bits (full EA) 1006 * 1007 * Used when a modem control message or line state inline in adaption 1008 * layer 2 is processed. Sort out the local modem state and throttles 1009 */ 1010 1011 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci, 1012 u32 modem, int clen) 1013 { 1014 int mlines = 0; 1015 u8 brk = 0; 1016 int fc; 1017 1018 /* The modem status command can either contain one octet (v.24 signals) 1019 or two octets (v.24 signals + break signals). The length field will 1020 either be 2 or 3 respectively. This is specified in section 1021 5.4.6.3.7 of the 27.010 mux spec. */ 1022 1023 if (clen == 2) 1024 modem = modem & 0x7f; 1025 else { 1026 brk = modem & 0x7f; 1027 modem = (modem >> 7) & 0x7f; 1028 } 1029 1030 /* Flow control/ready to communicate */ 1031 fc = (modem & MDM_FC) || !(modem & MDM_RTR); 1032 if (fc && !dlci->constipated) { 1033 /* Need to throttle our output on this device */ 1034 dlci->constipated = 1; 1035 } else if (!fc && dlci->constipated) { 1036 dlci->constipated = 0; 1037 gsm_dlci_data_kick(dlci); 1038 } 1039 1040 /* Map modem bits */ 1041 if (modem & MDM_RTC) 1042 mlines |= TIOCM_DSR | TIOCM_DTR; 1043 if (modem & MDM_RTR) 1044 mlines |= TIOCM_RTS | TIOCM_CTS; 1045 if (modem & MDM_IC) 1046 mlines |= TIOCM_RI; 1047 if (modem & MDM_DV) 1048 mlines |= TIOCM_CD; 1049 1050 /* Carrier drop -> hangup */ 1051 if (tty) { 1052 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD)) 1053 if (!C_CLOCAL(tty)) 1054 tty_hangup(tty); 1055 } 1056 if (brk & 0x01) 1057 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK); 1058 dlci->modem_rx = mlines; 1059 } 1060 1061 /** 1062 * gsm_control_modem - modem status received 1063 * @gsm: GSM channel 1064 * @data: data following command 1065 * @clen: command length 1066 * 1067 * We have received a modem status control message. This is used by 1068 * the GSM mux protocol to pass virtual modem line status and optionally 1069 * to indicate break signals. Unpack it, convert to Linux representation 1070 * and if need be stuff a break message down the tty. 1071 */ 1072 1073 static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen) 1074 { 1075 unsigned int addr = 0; 1076 unsigned int modem = 0; 1077 unsigned int brk = 0; 1078 struct gsm_dlci *dlci; 1079 int len = clen; 1080 u8 *dp = data; 1081 struct tty_struct *tty; 1082 1083 while (gsm_read_ea(&addr, *dp++) == 0) { 1084 len--; 1085 if (len == 0) 1086 return; 1087 } 1088 /* Must be at least one byte following the EA */ 1089 len--; 1090 if (len <= 0) 1091 return; 1092 1093 addr >>= 1; 1094 /* Closed port, or invalid ? */ 1095 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) 1096 return; 1097 dlci = gsm->dlci[addr]; 1098 1099 while (gsm_read_ea(&modem, *dp++) == 0) { 1100 len--; 1101 if (len == 0) 1102 return; 1103 } 1104 len--; 1105 if (len > 0) { 1106 while (gsm_read_ea(&brk, *dp++) == 0) { 1107 len--; 1108 if (len == 0) 1109 return; 1110 } 1111 modem <<= 7; 1112 modem |= (brk & 0x7f); 1113 } 1114 tty = tty_port_tty_get(&dlci->port); 1115 gsm_process_modem(tty, dlci, modem, clen); 1116 if (tty) { 1117 tty_wakeup(tty); 1118 tty_kref_put(tty); 1119 } 1120 gsm_control_reply(gsm, CMD_MSC, data, clen); 1121 } 1122 1123 /** 1124 * gsm_control_rls - remote line status 1125 * @gsm: GSM channel 1126 * @data: data bytes 1127 * @clen: data length 1128 * 1129 * The modem sends us a two byte message on the control channel whenever 1130 * it wishes to send us an error state from the virtual link. Stuff 1131 * this into the uplink tty if present 1132 */ 1133 1134 static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen) 1135 { 1136 struct tty_port *port; 1137 unsigned int addr = 0; 1138 u8 bits; 1139 int len = clen; 1140 u8 *dp = data; 1141 1142 while (gsm_read_ea(&addr, *dp++) == 0) { 1143 len--; 1144 if (len == 0) 1145 return; 1146 } 1147 /* Must be at least one byte following ea */ 1148 len--; 1149 if (len <= 0) 1150 return; 1151 addr >>= 1; 1152 /* Closed port, or invalid ? */ 1153 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) 1154 return; 1155 /* No error ? */ 1156 bits = *dp; 1157 if ((bits & 1) == 0) 1158 return; 1159 1160 port = &gsm->dlci[addr]->port; 1161 1162 if (bits & 2) 1163 tty_insert_flip_char(port, 0, TTY_OVERRUN); 1164 if (bits & 4) 1165 tty_insert_flip_char(port, 0, TTY_PARITY); 1166 if (bits & 8) 1167 tty_insert_flip_char(port, 0, TTY_FRAME); 1168 1169 tty_flip_buffer_push(port); 1170 1171 gsm_control_reply(gsm, CMD_RLS, data, clen); 1172 } 1173 1174 static void gsm_dlci_begin_close(struct gsm_dlci *dlci); 1175 1176 /** 1177 * gsm_control_message - DLCI 0 control processing 1178 * @gsm: our GSM mux 1179 * @command: the command EA 1180 * @data: data beyond the command/length EAs 1181 * @clen: length 1182 * 1183 * Input processor for control messages from the other end of the link. 1184 * Processes the incoming request and queues a response frame or an 1185 * NSC response if not supported 1186 */ 1187 1188 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, 1189 u8 *data, int clen) 1190 { 1191 u8 buf[1]; 1192 unsigned long flags; 1193 1194 switch (command) { 1195 case CMD_CLD: { 1196 struct gsm_dlci *dlci = gsm->dlci[0]; 1197 /* Modem wishes to close down */ 1198 if (dlci) { 1199 dlci->dead = 1; 1200 gsm->dead = 1; 1201 gsm_dlci_begin_close(dlci); 1202 } 1203 } 1204 break; 1205 case CMD_TEST: 1206 /* Modem wishes to test, reply with the data */ 1207 gsm_control_reply(gsm, CMD_TEST, data, clen); 1208 break; 1209 case CMD_FCON: 1210 /* Modem can accept data again */ 1211 gsm->constipated = 0; 1212 gsm_control_reply(gsm, CMD_FCON, NULL, 0); 1213 /* Kick the link in case it is idling */ 1214 spin_lock_irqsave(&gsm->tx_lock, flags); 1215 gsm_data_kick(gsm); 1216 spin_unlock_irqrestore(&gsm->tx_lock, flags); 1217 break; 1218 case CMD_FCOFF: 1219 /* Modem wants us to STFU */ 1220 gsm->constipated = 1; 1221 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0); 1222 break; 1223 case CMD_MSC: 1224 /* Out of band modem line change indicator for a DLCI */ 1225 gsm_control_modem(gsm, data, clen); 1226 break; 1227 case CMD_RLS: 1228 /* Out of band error reception for a DLCI */ 1229 gsm_control_rls(gsm, data, clen); 1230 break; 1231 case CMD_PSC: 1232 /* Modem wishes to enter power saving state */ 1233 gsm_control_reply(gsm, CMD_PSC, NULL, 0); 1234 break; 1235 /* Optional unsupported commands */ 1236 case CMD_PN: /* Parameter negotiation */ 1237 case CMD_RPN: /* Remote port negotiation */ 1238 case CMD_SNC: /* Service negotiation command */ 1239 default: 1240 /* Reply to bad commands with an NSC */ 1241 buf[0] = command; 1242 gsm_control_reply(gsm, CMD_NSC, buf, 1); 1243 break; 1244 } 1245 } 1246 1247 /** 1248 * gsm_control_response - process a response to our control 1249 * @gsm: our GSM mux 1250 * @command: the command (response) EA 1251 * @data: data beyond the command/length EA 1252 * @clen: length 1253 * 1254 * Process a response to an outstanding command. We only allow a single 1255 * control message in flight so this is fairly easy. All the clean up 1256 * is done by the caller, we just update the fields, flag it as done 1257 * and return 1258 */ 1259 1260 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command, 1261 u8 *data, int clen) 1262 { 1263 struct gsm_control *ctrl; 1264 unsigned long flags; 1265 1266 spin_lock_irqsave(&gsm->control_lock, flags); 1267 1268 ctrl = gsm->pending_cmd; 1269 /* Does the reply match our command */ 1270 command |= 1; 1271 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) { 1272 /* Our command was replied to, kill the retry timer */ 1273 del_timer(&gsm->t2_timer); 1274 gsm->pending_cmd = NULL; 1275 /* Rejected by the other end */ 1276 if (command == CMD_NSC) 1277 ctrl->error = -EOPNOTSUPP; 1278 ctrl->done = 1; 1279 wake_up(&gsm->event); 1280 } 1281 spin_unlock_irqrestore(&gsm->control_lock, flags); 1282 } 1283 1284 /** 1285 * gsm_control_transmit - send control packet 1286 * @gsm: gsm mux 1287 * @ctrl: frame to send 1288 * 1289 * Send out a pending control command (called under control lock) 1290 */ 1291 1292 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl) 1293 { 1294 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype); 1295 if (msg == NULL) 1296 return; 1297 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */ 1298 memcpy(msg->data + 1, ctrl->data, ctrl->len); 1299 gsm_data_queue(gsm->dlci[0], msg); 1300 } 1301 1302 /** 1303 * gsm_control_retransmit - retransmit a control frame 1304 * @data: pointer to our gsm object 1305 * 1306 * Called off the T2 timer expiry in order to retransmit control frames 1307 * that have been lost in the system somewhere. The control_lock protects 1308 * us from colliding with another sender or a receive completion event. 1309 * In that situation the timer may still occur in a small window but 1310 * gsm->pending_cmd will be NULL and we just let the timer expire. 1311 */ 1312 1313 static void gsm_control_retransmit(struct timer_list *t) 1314 { 1315 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer); 1316 struct gsm_control *ctrl; 1317 unsigned long flags; 1318 spin_lock_irqsave(&gsm->control_lock, flags); 1319 ctrl = gsm->pending_cmd; 1320 if (ctrl) { 1321 gsm->cretries--; 1322 if (gsm->cretries == 0) { 1323 gsm->pending_cmd = NULL; 1324 ctrl->error = -ETIMEDOUT; 1325 ctrl->done = 1; 1326 spin_unlock_irqrestore(&gsm->control_lock, flags); 1327 wake_up(&gsm->event); 1328 return; 1329 } 1330 gsm_control_transmit(gsm, ctrl); 1331 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); 1332 } 1333 spin_unlock_irqrestore(&gsm->control_lock, flags); 1334 } 1335 1336 /** 1337 * gsm_control_send - send a control frame on DLCI 0 1338 * @gsm: the GSM channel 1339 * @command: command to send including CR bit 1340 * @data: bytes of data (must be kmalloced) 1341 * @len: length of the block to send 1342 * 1343 * Queue and dispatch a control command. Only one command can be 1344 * active at a time. In theory more can be outstanding but the matching 1345 * gets really complicated so for now stick to one outstanding. 1346 */ 1347 1348 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm, 1349 unsigned int command, u8 *data, int clen) 1350 { 1351 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control), 1352 GFP_KERNEL); 1353 unsigned long flags; 1354 if (ctrl == NULL) 1355 return NULL; 1356 retry: 1357 wait_event(gsm->event, gsm->pending_cmd == NULL); 1358 spin_lock_irqsave(&gsm->control_lock, flags); 1359 if (gsm->pending_cmd != NULL) { 1360 spin_unlock_irqrestore(&gsm->control_lock, flags); 1361 goto retry; 1362 } 1363 ctrl->cmd = command; 1364 ctrl->data = data; 1365 ctrl->len = clen; 1366 gsm->pending_cmd = ctrl; 1367 gsm->cretries = gsm->n2; 1368 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); 1369 gsm_control_transmit(gsm, ctrl); 1370 spin_unlock_irqrestore(&gsm->control_lock, flags); 1371 return ctrl; 1372 } 1373 1374 /** 1375 * gsm_control_wait - wait for a control to finish 1376 * @gsm: GSM mux 1377 * @control: control we are waiting on 1378 * 1379 * Waits for the control to complete or time out. Frees any used 1380 * resources and returns 0 for success, or an error if the remote 1381 * rejected or ignored the request. 1382 */ 1383 1384 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control) 1385 { 1386 int err; 1387 wait_event(gsm->event, control->done == 1); 1388 err = control->error; 1389 kfree(control); 1390 return err; 1391 } 1392 1393 1394 /* 1395 * DLCI level handling: Needs krefs 1396 */ 1397 1398 /* 1399 * State transitions and timers 1400 */ 1401 1402 /** 1403 * gsm_dlci_close - a DLCI has closed 1404 * @dlci: DLCI that closed 1405 * 1406 * Perform processing when moving a DLCI into closed state. If there 1407 * is an attached tty this is hung up 1408 */ 1409 1410 static void gsm_dlci_close(struct gsm_dlci *dlci) 1411 { 1412 del_timer(&dlci->t1); 1413 if (debug & 8) 1414 pr_debug("DLCI %d goes closed.\n", dlci->addr); 1415 dlci->state = DLCI_CLOSED; 1416 if (dlci->addr != 0) { 1417 tty_port_tty_hangup(&dlci->port, false); 1418 kfifo_reset(dlci->fifo); 1419 } else 1420 dlci->gsm->dead = 1; 1421 wake_up(&dlci->gsm->event); 1422 /* A DLCI 0 close is a MUX termination so we need to kick that 1423 back to userspace somehow */ 1424 } 1425 1426 /** 1427 * gsm_dlci_open - a DLCI has opened 1428 * @dlci: DLCI that opened 1429 * 1430 * Perform processing when moving a DLCI into open state. 1431 */ 1432 1433 static void gsm_dlci_open(struct gsm_dlci *dlci) 1434 { 1435 /* Note that SABM UA .. SABM UA first UA lost can mean that we go 1436 open -> open */ 1437 del_timer(&dlci->t1); 1438 /* This will let a tty open continue */ 1439 dlci->state = DLCI_OPEN; 1440 if (debug & 8) 1441 pr_debug("DLCI %d goes open.\n", dlci->addr); 1442 wake_up(&dlci->gsm->event); 1443 } 1444 1445 /** 1446 * gsm_dlci_t1 - T1 timer expiry 1447 * @dlci: DLCI that opened 1448 * 1449 * The T1 timer handles retransmits of control frames (essentially of 1450 * SABM and DISC). We resend the command until the retry count runs out 1451 * in which case an opening port goes back to closed and a closing port 1452 * is simply put into closed state (any further frames from the other 1453 * end will get a DM response) 1454 */ 1455 1456 static void gsm_dlci_t1(struct timer_list *t) 1457 { 1458 struct gsm_dlci *dlci = from_timer(dlci, t, t1); 1459 struct gsm_mux *gsm = dlci->gsm; 1460 1461 switch (dlci->state) { 1462 case DLCI_OPENING: 1463 dlci->retries--; 1464 if (dlci->retries) { 1465 gsm_command(dlci->gsm, dlci->addr, SABM|PF); 1466 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1467 } else 1468 gsm_dlci_close(dlci); 1469 break; 1470 case DLCI_CLOSING: 1471 dlci->retries--; 1472 if (dlci->retries) { 1473 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 1474 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1475 } else 1476 gsm_dlci_close(dlci); 1477 break; 1478 } 1479 } 1480 1481 /** 1482 * gsm_dlci_begin_open - start channel open procedure 1483 * @dlci: DLCI to open 1484 * 1485 * Commence opening a DLCI from the Linux side. We issue SABM messages 1486 * to the modem which should then reply with a UA, at which point we 1487 * will move into open state. Opening is done asynchronously with retry 1488 * running off timers and the responses. 1489 */ 1490 1491 static void gsm_dlci_begin_open(struct gsm_dlci *dlci) 1492 { 1493 struct gsm_mux *gsm = dlci->gsm; 1494 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING) 1495 return; 1496 dlci->retries = gsm->n2; 1497 dlci->state = DLCI_OPENING; 1498 gsm_command(dlci->gsm, dlci->addr, SABM|PF); 1499 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1500 } 1501 1502 /** 1503 * gsm_dlci_begin_close - start channel open procedure 1504 * @dlci: DLCI to open 1505 * 1506 * Commence closing a DLCI from the Linux side. We issue DISC messages 1507 * to the modem which should then reply with a UA, at which point we 1508 * will move into closed state. Closing is done asynchronously with retry 1509 * off timers. We may also receive a DM reply from the other end which 1510 * indicates the channel was already closed. 1511 */ 1512 1513 static void gsm_dlci_begin_close(struct gsm_dlci *dlci) 1514 { 1515 struct gsm_mux *gsm = dlci->gsm; 1516 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING) 1517 return; 1518 dlci->retries = gsm->n2; 1519 dlci->state = DLCI_CLOSING; 1520 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 1521 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1522 } 1523 1524 /** 1525 * gsm_dlci_data - data arrived 1526 * @dlci: channel 1527 * @data: block of bytes received 1528 * @len: length of received block 1529 * 1530 * A UI or UIH frame has arrived which contains data for a channel 1531 * other than the control channel. If the relevant virtual tty is 1532 * open we shovel the bits down it, if not we drop them. 1533 */ 1534 1535 static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen) 1536 { 1537 /* krefs .. */ 1538 struct tty_port *port = &dlci->port; 1539 struct tty_struct *tty; 1540 unsigned int modem = 0; 1541 int len = clen; 1542 1543 if (debug & 16) 1544 pr_debug("%d bytes for tty\n", len); 1545 switch (dlci->adaption) { 1546 /* Unsupported types */ 1547 /* Packetised interruptible data */ 1548 case 4: 1549 break; 1550 /* Packetised uininterruptible voice/data */ 1551 case 3: 1552 break; 1553 /* Asynchronous serial with line state in each frame */ 1554 case 2: 1555 while (gsm_read_ea(&modem, *data++) == 0) { 1556 len--; 1557 if (len == 0) 1558 return; 1559 } 1560 tty = tty_port_tty_get(port); 1561 if (tty) { 1562 gsm_process_modem(tty, dlci, modem, clen); 1563 tty_kref_put(tty); 1564 } 1565 /* Line state will go via DLCI 0 controls only */ 1566 case 1: 1567 default: 1568 tty_insert_flip_string(port, data, len); 1569 tty_flip_buffer_push(port); 1570 } 1571 } 1572 1573 /** 1574 * gsm_dlci_control - data arrived on control channel 1575 * @dlci: channel 1576 * @data: block of bytes received 1577 * @len: length of received block 1578 * 1579 * A UI or UIH frame has arrived which contains data for DLCI 0 the 1580 * control channel. This should contain a command EA followed by 1581 * control data bytes. The command EA contains a command/response bit 1582 * and we divide up the work accordingly. 1583 */ 1584 1585 static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len) 1586 { 1587 /* See what command is involved */ 1588 unsigned int command = 0; 1589 while (len-- > 0) { 1590 if (gsm_read_ea(&command, *data++) == 1) { 1591 int clen = *data++; 1592 len--; 1593 /* FIXME: this is properly an EA */ 1594 clen >>= 1; 1595 /* Malformed command ? */ 1596 if (clen > len) 1597 return; 1598 if (command & 1) 1599 gsm_control_message(dlci->gsm, command, 1600 data, clen); 1601 else 1602 gsm_control_response(dlci->gsm, command, 1603 data, clen); 1604 return; 1605 } 1606 } 1607 } 1608 1609 /* 1610 * Allocate/Free DLCI channels 1611 */ 1612 1613 /** 1614 * gsm_dlci_alloc - allocate a DLCI 1615 * @gsm: GSM mux 1616 * @addr: address of the DLCI 1617 * 1618 * Allocate and install a new DLCI object into the GSM mux. 1619 * 1620 * FIXME: review locking races 1621 */ 1622 1623 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr) 1624 { 1625 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC); 1626 if (dlci == NULL) 1627 return NULL; 1628 spin_lock_init(&dlci->lock); 1629 mutex_init(&dlci->mutex); 1630 dlci->fifo = &dlci->_fifo; 1631 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) { 1632 kfree(dlci); 1633 return NULL; 1634 } 1635 1636 skb_queue_head_init(&dlci->skb_list); 1637 timer_setup(&dlci->t1, gsm_dlci_t1, 0); 1638 tty_port_init(&dlci->port); 1639 dlci->port.ops = &gsm_port_ops; 1640 dlci->gsm = gsm; 1641 dlci->addr = addr; 1642 dlci->adaption = gsm->adaption; 1643 dlci->state = DLCI_CLOSED; 1644 if (addr) 1645 dlci->data = gsm_dlci_data; 1646 else 1647 dlci->data = gsm_dlci_command; 1648 gsm->dlci[addr] = dlci; 1649 return dlci; 1650 } 1651 1652 /** 1653 * gsm_dlci_free - free DLCI 1654 * @dlci: DLCI to free 1655 * 1656 * Free up a DLCI. 1657 * 1658 * Can sleep. 1659 */ 1660 static void gsm_dlci_free(struct tty_port *port) 1661 { 1662 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 1663 1664 del_timer_sync(&dlci->t1); 1665 dlci->gsm->dlci[dlci->addr] = NULL; 1666 kfifo_free(dlci->fifo); 1667 while ((dlci->skb = skb_dequeue(&dlci->skb_list))) 1668 dev_kfree_skb(dlci->skb); 1669 kfree(dlci); 1670 } 1671 1672 static inline void dlci_get(struct gsm_dlci *dlci) 1673 { 1674 tty_port_get(&dlci->port); 1675 } 1676 1677 static inline void dlci_put(struct gsm_dlci *dlci) 1678 { 1679 tty_port_put(&dlci->port); 1680 } 1681 1682 static void gsm_destroy_network(struct gsm_dlci *dlci); 1683 1684 /** 1685 * gsm_dlci_release - release DLCI 1686 * @dlci: DLCI to destroy 1687 * 1688 * Release a DLCI. Actual free is deferred until either 1689 * mux is closed or tty is closed - whichever is last. 1690 * 1691 * Can sleep. 1692 */ 1693 static void gsm_dlci_release(struct gsm_dlci *dlci) 1694 { 1695 struct tty_struct *tty = tty_port_tty_get(&dlci->port); 1696 if (tty) { 1697 mutex_lock(&dlci->mutex); 1698 gsm_destroy_network(dlci); 1699 mutex_unlock(&dlci->mutex); 1700 1701 tty_vhangup(tty); 1702 1703 tty_port_tty_set(&dlci->port, NULL); 1704 tty_kref_put(tty); 1705 } 1706 dlci->state = DLCI_CLOSED; 1707 dlci_put(dlci); 1708 } 1709 1710 /* 1711 * LAPBish link layer logic 1712 */ 1713 1714 /** 1715 * gsm_queue - a GSM frame is ready to process 1716 * @gsm: pointer to our gsm mux 1717 * 1718 * At this point in time a frame has arrived and been demangled from 1719 * the line encoding. All the differences between the encodings have 1720 * been handled below us and the frame is unpacked into the structures. 1721 * The fcs holds the header FCS but any data FCS must be added here. 1722 */ 1723 1724 static void gsm_queue(struct gsm_mux *gsm) 1725 { 1726 struct gsm_dlci *dlci; 1727 u8 cr; 1728 int address; 1729 /* We have to sneak a look at the packet body to do the FCS. 1730 A somewhat layering violation in the spec */ 1731 1732 if ((gsm->control & ~PF) == UI) 1733 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len); 1734 if (gsm->encoding == 0) { 1735 /* WARNING: gsm->received_fcs is used for 1736 gsm->encoding = 0 only. 1737 In this case it contain the last piece of data 1738 required to generate final CRC */ 1739 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs); 1740 } 1741 if (gsm->fcs != GOOD_FCS) { 1742 gsm->bad_fcs++; 1743 if (debug & 4) 1744 pr_debug("BAD FCS %02x\n", gsm->fcs); 1745 return; 1746 } 1747 address = gsm->address >> 1; 1748 if (address >= NUM_DLCI) 1749 goto invalid; 1750 1751 cr = gsm->address & 1; /* C/R bit */ 1752 1753 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len); 1754 1755 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */ 1756 dlci = gsm->dlci[address]; 1757 1758 switch (gsm->control) { 1759 case SABM|PF: 1760 if (cr == 0) 1761 goto invalid; 1762 if (dlci == NULL) 1763 dlci = gsm_dlci_alloc(gsm, address); 1764 if (dlci == NULL) 1765 return; 1766 if (dlci->dead) 1767 gsm_response(gsm, address, DM); 1768 else { 1769 gsm_response(gsm, address, UA); 1770 gsm_dlci_open(dlci); 1771 } 1772 break; 1773 case DISC|PF: 1774 if (cr == 0) 1775 goto invalid; 1776 if (dlci == NULL || dlci->state == DLCI_CLOSED) { 1777 gsm_response(gsm, address, DM); 1778 return; 1779 } 1780 /* Real close complete */ 1781 gsm_response(gsm, address, UA); 1782 gsm_dlci_close(dlci); 1783 break; 1784 case UA: 1785 case UA|PF: 1786 if (cr == 0 || dlci == NULL) 1787 break; 1788 switch (dlci->state) { 1789 case DLCI_CLOSING: 1790 gsm_dlci_close(dlci); 1791 break; 1792 case DLCI_OPENING: 1793 gsm_dlci_open(dlci); 1794 break; 1795 } 1796 break; 1797 case DM: /* DM can be valid unsolicited */ 1798 case DM|PF: 1799 if (cr) 1800 goto invalid; 1801 if (dlci == NULL) 1802 return; 1803 gsm_dlci_close(dlci); 1804 break; 1805 case UI: 1806 case UI|PF: 1807 case UIH: 1808 case UIH|PF: 1809 #if 0 1810 if (cr) 1811 goto invalid; 1812 #endif 1813 if (dlci == NULL || dlci->state != DLCI_OPEN) { 1814 gsm_command(gsm, address, DM|PF); 1815 return; 1816 } 1817 dlci->data(dlci, gsm->buf, gsm->len); 1818 break; 1819 default: 1820 goto invalid; 1821 } 1822 return; 1823 invalid: 1824 gsm->malformed++; 1825 return; 1826 } 1827 1828 1829 /** 1830 * gsm0_receive - perform processing for non-transparency 1831 * @gsm: gsm data for this ldisc instance 1832 * @c: character 1833 * 1834 * Receive bytes in gsm mode 0 1835 */ 1836 1837 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) 1838 { 1839 unsigned int len; 1840 1841 switch (gsm->state) { 1842 case GSM_SEARCH: /* SOF marker */ 1843 if (c == GSM0_SOF) { 1844 gsm->state = GSM_ADDRESS; 1845 gsm->address = 0; 1846 gsm->len = 0; 1847 gsm->fcs = INIT_FCS; 1848 } 1849 break; 1850 case GSM_ADDRESS: /* Address EA */ 1851 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1852 if (gsm_read_ea(&gsm->address, c)) 1853 gsm->state = GSM_CONTROL; 1854 break; 1855 case GSM_CONTROL: /* Control Byte */ 1856 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1857 gsm->control = c; 1858 gsm->state = GSM_LEN0; 1859 break; 1860 case GSM_LEN0: /* Length EA */ 1861 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1862 if (gsm_read_ea(&gsm->len, c)) { 1863 if (gsm->len > gsm->mru) { 1864 gsm->bad_size++; 1865 gsm->state = GSM_SEARCH; 1866 break; 1867 } 1868 gsm->count = 0; 1869 if (!gsm->len) 1870 gsm->state = GSM_FCS; 1871 else 1872 gsm->state = GSM_DATA; 1873 break; 1874 } 1875 gsm->state = GSM_LEN1; 1876 break; 1877 case GSM_LEN1: 1878 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1879 len = c; 1880 gsm->len |= len << 7; 1881 if (gsm->len > gsm->mru) { 1882 gsm->bad_size++; 1883 gsm->state = GSM_SEARCH; 1884 break; 1885 } 1886 gsm->count = 0; 1887 if (!gsm->len) 1888 gsm->state = GSM_FCS; 1889 else 1890 gsm->state = GSM_DATA; 1891 break; 1892 case GSM_DATA: /* Data */ 1893 gsm->buf[gsm->count++] = c; 1894 if (gsm->count == gsm->len) 1895 gsm->state = GSM_FCS; 1896 break; 1897 case GSM_FCS: /* FCS follows the packet */ 1898 gsm->received_fcs = c; 1899 gsm_queue(gsm); 1900 gsm->state = GSM_SSOF; 1901 break; 1902 case GSM_SSOF: 1903 if (c == GSM0_SOF) { 1904 gsm->state = GSM_SEARCH; 1905 break; 1906 } 1907 break; 1908 } 1909 } 1910 1911 /** 1912 * gsm1_receive - perform processing for non-transparency 1913 * @gsm: gsm data for this ldisc instance 1914 * @c: character 1915 * 1916 * Receive bytes in mode 1 (Advanced option) 1917 */ 1918 1919 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c) 1920 { 1921 if (c == GSM1_SOF) { 1922 /* EOF is only valid in frame if we have got to the data state 1923 and received at least one byte (the FCS) */ 1924 if (gsm->state == GSM_DATA && gsm->count) { 1925 /* Extract the FCS */ 1926 gsm->count--; 1927 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]); 1928 gsm->len = gsm->count; 1929 gsm_queue(gsm); 1930 gsm->state = GSM_START; 1931 return; 1932 } 1933 /* Any partial frame was a runt so go back to start */ 1934 if (gsm->state != GSM_START) { 1935 gsm->malformed++; 1936 gsm->state = GSM_START; 1937 } 1938 /* A SOF in GSM_START means we are still reading idling or 1939 framing bytes */ 1940 return; 1941 } 1942 1943 if (c == GSM1_ESCAPE) { 1944 gsm->escape = 1; 1945 return; 1946 } 1947 1948 /* Only an unescaped SOF gets us out of GSM search */ 1949 if (gsm->state == GSM_SEARCH) 1950 return; 1951 1952 if (gsm->escape) { 1953 c ^= GSM1_ESCAPE_BITS; 1954 gsm->escape = 0; 1955 } 1956 switch (gsm->state) { 1957 case GSM_START: /* First byte after SOF */ 1958 gsm->address = 0; 1959 gsm->state = GSM_ADDRESS; 1960 gsm->fcs = INIT_FCS; 1961 /* Drop through */ 1962 case GSM_ADDRESS: /* Address continuation */ 1963 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1964 if (gsm_read_ea(&gsm->address, c)) 1965 gsm->state = GSM_CONTROL; 1966 break; 1967 case GSM_CONTROL: /* Control Byte */ 1968 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1969 gsm->control = c; 1970 gsm->count = 0; 1971 gsm->state = GSM_DATA; 1972 break; 1973 case GSM_DATA: /* Data */ 1974 if (gsm->count > gsm->mru) { /* Allow one for the FCS */ 1975 gsm->state = GSM_OVERRUN; 1976 gsm->bad_size++; 1977 } else 1978 gsm->buf[gsm->count++] = c; 1979 break; 1980 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */ 1981 break; 1982 } 1983 } 1984 1985 /** 1986 * gsm_error - handle tty error 1987 * @gsm: ldisc data 1988 * @data: byte received (may be invalid) 1989 * @flag: error received 1990 * 1991 * Handle an error in the receipt of data for a frame. Currently we just 1992 * go back to hunting for a SOF. 1993 * 1994 * FIXME: better diagnostics ? 1995 */ 1996 1997 static void gsm_error(struct gsm_mux *gsm, 1998 unsigned char data, unsigned char flag) 1999 { 2000 gsm->state = GSM_SEARCH; 2001 gsm->io_error++; 2002 } 2003 2004 static int gsm_disconnect(struct gsm_mux *gsm) 2005 { 2006 struct gsm_dlci *dlci = gsm->dlci[0]; 2007 struct gsm_control *gc; 2008 2009 if (!dlci) 2010 return 0; 2011 2012 /* In theory disconnecting DLCI 0 is sufficient but for some 2013 modems this is apparently not the case. */ 2014 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0); 2015 if (gc) 2016 gsm_control_wait(gsm, gc); 2017 2018 del_timer_sync(&gsm->t2_timer); 2019 /* Now we are sure T2 has stopped */ 2020 2021 gsm_dlci_begin_close(dlci); 2022 wait_event_interruptible(gsm->event, 2023 dlci->state == DLCI_CLOSED); 2024 2025 if (signal_pending(current)) 2026 return -EINTR; 2027 2028 return 0; 2029 } 2030 2031 /** 2032 * gsm_cleanup_mux - generic GSM protocol cleanup 2033 * @gsm: our mux 2034 * 2035 * Clean up the bits of the mux which are the same for all framing 2036 * protocols. Remove the mux from the mux table, stop all the timers 2037 * and then shut down each device hanging up the channels as we go. 2038 */ 2039 2040 static void gsm_cleanup_mux(struct gsm_mux *gsm) 2041 { 2042 int i; 2043 struct gsm_dlci *dlci = gsm->dlci[0]; 2044 struct gsm_msg *txq, *ntxq; 2045 2046 gsm->dead = 1; 2047 2048 spin_lock(&gsm_mux_lock); 2049 for (i = 0; i < MAX_MUX; i++) { 2050 if (gsm_mux[i] == gsm) { 2051 gsm_mux[i] = NULL; 2052 break; 2053 } 2054 } 2055 spin_unlock(&gsm_mux_lock); 2056 /* open failed before registering => nothing to do */ 2057 if (i == MAX_MUX) 2058 return; 2059 2060 del_timer_sync(&gsm->t2_timer); 2061 /* Now we are sure T2 has stopped */ 2062 if (dlci) 2063 dlci->dead = 1; 2064 2065 /* Free up any link layer users */ 2066 mutex_lock(&gsm->mutex); 2067 for (i = 0; i < NUM_DLCI; i++) 2068 if (gsm->dlci[i]) 2069 gsm_dlci_release(gsm->dlci[i]); 2070 mutex_unlock(&gsm->mutex); 2071 /* Now wipe the queues */ 2072 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list) 2073 kfree(txq); 2074 INIT_LIST_HEAD(&gsm->tx_list); 2075 } 2076 2077 /** 2078 * gsm_activate_mux - generic GSM setup 2079 * @gsm: our mux 2080 * 2081 * Set up the bits of the mux which are the same for all framing 2082 * protocols. Add the mux to the mux table so it can be opened and 2083 * finally kick off connecting to DLCI 0 on the modem. 2084 */ 2085 2086 static int gsm_activate_mux(struct gsm_mux *gsm) 2087 { 2088 struct gsm_dlci *dlci; 2089 int i = 0; 2090 2091 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0); 2092 init_waitqueue_head(&gsm->event); 2093 spin_lock_init(&gsm->control_lock); 2094 spin_lock_init(&gsm->tx_lock); 2095 2096 if (gsm->encoding == 0) 2097 gsm->receive = gsm0_receive; 2098 else 2099 gsm->receive = gsm1_receive; 2100 gsm->error = gsm_error; 2101 2102 spin_lock(&gsm_mux_lock); 2103 for (i = 0; i < MAX_MUX; i++) { 2104 if (gsm_mux[i] == NULL) { 2105 gsm->num = i; 2106 gsm_mux[i] = gsm; 2107 break; 2108 } 2109 } 2110 spin_unlock(&gsm_mux_lock); 2111 if (i == MAX_MUX) 2112 return -EBUSY; 2113 2114 dlci = gsm_dlci_alloc(gsm, 0); 2115 if (dlci == NULL) 2116 return -ENOMEM; 2117 gsm->dead = 0; /* Tty opens are now permissible */ 2118 return 0; 2119 } 2120 2121 /** 2122 * gsm_free_mux - free up a mux 2123 * @mux: mux to free 2124 * 2125 * Dispose of allocated resources for a dead mux 2126 */ 2127 static void gsm_free_mux(struct gsm_mux *gsm) 2128 { 2129 kfree(gsm->txframe); 2130 kfree(gsm->buf); 2131 kfree(gsm); 2132 } 2133 2134 /** 2135 * gsm_free_muxr - free up a mux 2136 * @mux: mux to free 2137 * 2138 * Dispose of allocated resources for a dead mux 2139 */ 2140 static void gsm_free_muxr(struct kref *ref) 2141 { 2142 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref); 2143 gsm_free_mux(gsm); 2144 } 2145 2146 static inline void mux_get(struct gsm_mux *gsm) 2147 { 2148 kref_get(&gsm->ref); 2149 } 2150 2151 static inline void mux_put(struct gsm_mux *gsm) 2152 { 2153 kref_put(&gsm->ref, gsm_free_muxr); 2154 } 2155 2156 /** 2157 * gsm_alloc_mux - allocate a mux 2158 * 2159 * Creates a new mux ready for activation. 2160 */ 2161 2162 static struct gsm_mux *gsm_alloc_mux(void) 2163 { 2164 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL); 2165 if (gsm == NULL) 2166 return NULL; 2167 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL); 2168 if (gsm->buf == NULL) { 2169 kfree(gsm); 2170 return NULL; 2171 } 2172 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL); 2173 if (gsm->txframe == NULL) { 2174 kfree(gsm->buf); 2175 kfree(gsm); 2176 return NULL; 2177 } 2178 spin_lock_init(&gsm->lock); 2179 mutex_init(&gsm->mutex); 2180 kref_init(&gsm->ref); 2181 INIT_LIST_HEAD(&gsm->tx_list); 2182 2183 gsm->t1 = T1; 2184 gsm->t2 = T2; 2185 gsm->n2 = N2; 2186 gsm->ftype = UIH; 2187 gsm->adaption = 1; 2188 gsm->encoding = 1; 2189 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */ 2190 gsm->mtu = 64; 2191 gsm->dead = 1; /* Avoid early tty opens */ 2192 2193 return gsm; 2194 } 2195 2196 /** 2197 * gsmld_output - write to link 2198 * @gsm: our mux 2199 * @data: bytes to output 2200 * @len: size 2201 * 2202 * Write a block of data from the GSM mux to the data channel. This 2203 * will eventually be serialized from above but at the moment isn't. 2204 */ 2205 2206 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len) 2207 { 2208 if (tty_write_room(gsm->tty) < len) { 2209 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags); 2210 return -ENOSPC; 2211 } 2212 if (debug & 4) 2213 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET, 2214 data, len); 2215 gsm->tty->ops->write(gsm->tty, data, len); 2216 return len; 2217 } 2218 2219 /** 2220 * gsmld_attach_gsm - mode set up 2221 * @tty: our tty structure 2222 * @gsm: our mux 2223 * 2224 * Set up the MUX for basic mode and commence connecting to the 2225 * modem. Currently called from the line discipline set up but 2226 * will need moving to an ioctl path. 2227 */ 2228 2229 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 2230 { 2231 int ret, i, base; 2232 2233 gsm->tty = tty_kref_get(tty); 2234 gsm->output = gsmld_output; 2235 ret = gsm_activate_mux(gsm); 2236 if (ret != 0) 2237 tty_kref_put(gsm->tty); 2238 else { 2239 /* Don't register device 0 - this is the control channel and not 2240 a usable tty interface */ 2241 base = gsm->num << 6; /* Base for this MUX */ 2242 for (i = 1; i < NUM_DLCI; i++) 2243 tty_register_device(gsm_tty_driver, base + i, NULL); 2244 } 2245 return ret; 2246 } 2247 2248 2249 /** 2250 * gsmld_detach_gsm - stop doing 0710 mux 2251 * @tty: tty attached to the mux 2252 * @gsm: mux 2253 * 2254 * Shutdown and then clean up the resources used by the line discipline 2255 */ 2256 2257 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 2258 { 2259 int i; 2260 int base = gsm->num << 6; /* Base for this MUX */ 2261 2262 WARN_ON(tty != gsm->tty); 2263 for (i = 1; i < NUM_DLCI; i++) 2264 tty_unregister_device(gsm_tty_driver, base + i); 2265 gsm_cleanup_mux(gsm); 2266 tty_kref_put(gsm->tty); 2267 gsm->tty = NULL; 2268 } 2269 2270 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, 2271 char *fp, int count) 2272 { 2273 struct gsm_mux *gsm = tty->disc_data; 2274 const unsigned char *dp; 2275 char *f; 2276 int i; 2277 char flags = TTY_NORMAL; 2278 2279 if (debug & 4) 2280 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET, 2281 cp, count); 2282 2283 for (i = count, dp = cp, f = fp; i; i--, dp++) { 2284 if (f) 2285 flags = *f++; 2286 switch (flags) { 2287 case TTY_NORMAL: 2288 gsm->receive(gsm, *dp); 2289 break; 2290 case TTY_OVERRUN: 2291 case TTY_BREAK: 2292 case TTY_PARITY: 2293 case TTY_FRAME: 2294 gsm->error(gsm, *dp, flags); 2295 break; 2296 default: 2297 WARN_ONCE(1, "%s: unknown flag %d\n", 2298 tty_name(tty), flags); 2299 break; 2300 } 2301 } 2302 /* FASYNC if needed ? */ 2303 /* If clogged call tty_throttle(tty); */ 2304 } 2305 2306 /** 2307 * gsmld_flush_buffer - clean input queue 2308 * @tty: terminal device 2309 * 2310 * Flush the input buffer. Called when the line discipline is 2311 * being closed, when the tty layer wants the buffer flushed (eg 2312 * at hangup). 2313 */ 2314 2315 static void gsmld_flush_buffer(struct tty_struct *tty) 2316 { 2317 } 2318 2319 /** 2320 * gsmld_close - close the ldisc for this tty 2321 * @tty: device 2322 * 2323 * Called from the terminal layer when this line discipline is 2324 * being shut down, either because of a close or becsuse of a 2325 * discipline change. The function will not be called while other 2326 * ldisc methods are in progress. 2327 */ 2328 2329 static void gsmld_close(struct tty_struct *tty) 2330 { 2331 struct gsm_mux *gsm = tty->disc_data; 2332 2333 gsmld_detach_gsm(tty, gsm); 2334 2335 gsmld_flush_buffer(tty); 2336 /* Do other clean up here */ 2337 mux_put(gsm); 2338 } 2339 2340 /** 2341 * gsmld_open - open an ldisc 2342 * @tty: terminal to open 2343 * 2344 * Called when this line discipline is being attached to the 2345 * terminal device. Can sleep. Called serialized so that no 2346 * other events will occur in parallel. No further open will occur 2347 * until a close. 2348 */ 2349 2350 static int gsmld_open(struct tty_struct *tty) 2351 { 2352 struct gsm_mux *gsm; 2353 int ret; 2354 2355 if (tty->ops->write == NULL) 2356 return -EINVAL; 2357 2358 /* Attach our ldisc data */ 2359 gsm = gsm_alloc_mux(); 2360 if (gsm == NULL) 2361 return -ENOMEM; 2362 2363 tty->disc_data = gsm; 2364 tty->receive_room = 65536; 2365 2366 /* Attach the initial passive connection */ 2367 gsm->encoding = 1; 2368 2369 ret = gsmld_attach_gsm(tty, gsm); 2370 if (ret != 0) { 2371 gsm_cleanup_mux(gsm); 2372 mux_put(gsm); 2373 } 2374 return ret; 2375 } 2376 2377 /** 2378 * gsmld_write_wakeup - asynchronous I/O notifier 2379 * @tty: tty device 2380 * 2381 * Required for the ptys, serial driver etc. since processes 2382 * that attach themselves to the master and rely on ASYNC 2383 * IO must be woken up 2384 */ 2385 2386 static void gsmld_write_wakeup(struct tty_struct *tty) 2387 { 2388 struct gsm_mux *gsm = tty->disc_data; 2389 unsigned long flags; 2390 2391 /* Queue poll */ 2392 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 2393 spin_lock_irqsave(&gsm->tx_lock, flags); 2394 gsm_data_kick(gsm); 2395 if (gsm->tx_bytes < TX_THRESH_LO) { 2396 gsm_dlci_data_sweep(gsm); 2397 } 2398 spin_unlock_irqrestore(&gsm->tx_lock, flags); 2399 } 2400 2401 /** 2402 * gsmld_read - read function for tty 2403 * @tty: tty device 2404 * @file: file object 2405 * @buf: userspace buffer pointer 2406 * @nr: size of I/O 2407 * 2408 * Perform reads for the line discipline. We are guaranteed that the 2409 * line discipline will not be closed under us but we may get multiple 2410 * parallel readers and must handle this ourselves. We may also get 2411 * a hangup. Always called in user context, may sleep. 2412 * 2413 * This code must be sure never to sleep through a hangup. 2414 */ 2415 2416 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, 2417 unsigned char __user *buf, size_t nr) 2418 { 2419 return -EOPNOTSUPP; 2420 } 2421 2422 /** 2423 * gsmld_write - write function for tty 2424 * @tty: tty device 2425 * @file: file object 2426 * @buf: userspace buffer pointer 2427 * @nr: size of I/O 2428 * 2429 * Called when the owner of the device wants to send a frame 2430 * itself (or some other control data). The data is transferred 2431 * as-is and must be properly framed and checksummed as appropriate 2432 * by userspace. Frames are either sent whole or not at all as this 2433 * avoids pain user side. 2434 */ 2435 2436 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file, 2437 const unsigned char *buf, size_t nr) 2438 { 2439 int space = tty_write_room(tty); 2440 if (space >= nr) 2441 return tty->ops->write(tty, buf, nr); 2442 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 2443 return -ENOBUFS; 2444 } 2445 2446 /** 2447 * gsmld_poll - poll method for N_GSM0710 2448 * @tty: terminal device 2449 * @file: file accessing it 2450 * @wait: poll table 2451 * 2452 * Called when the line discipline is asked to poll() for data or 2453 * for special events. This code is not serialized with respect to 2454 * other events save open/close. 2455 * 2456 * This code must be sure never to sleep through a hangup. 2457 * Called without the kernel lock held - fine 2458 */ 2459 2460 static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file, 2461 poll_table *wait) 2462 { 2463 unsigned int mask = 0; 2464 struct gsm_mux *gsm = tty->disc_data; 2465 2466 poll_wait(file, &tty->read_wait, wait); 2467 poll_wait(file, &tty->write_wait, wait); 2468 if (tty_hung_up_p(file)) 2469 mask |= POLLHUP; 2470 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0) 2471 mask |= POLLOUT | POLLWRNORM; 2472 if (gsm->dead) 2473 mask |= POLLHUP; 2474 return mask; 2475 } 2476 2477 static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm, 2478 struct gsm_config *c) 2479 { 2480 int need_close = 0; 2481 int need_restart = 0; 2482 2483 /* Stuff we don't support yet - UI or I frame transport, windowing */ 2484 if ((c->adaption != 1 && c->adaption != 2) || c->k) 2485 return -EOPNOTSUPP; 2486 /* Check the MRU/MTU range looks sane */ 2487 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8) 2488 return -EINVAL; 2489 if (c->n2 < 3) 2490 return -EINVAL; 2491 if (c->encapsulation > 1) /* Basic, advanced, no I */ 2492 return -EINVAL; 2493 if (c->initiator > 1) 2494 return -EINVAL; 2495 if (c->i == 0 || c->i > 2) /* UIH and UI only */ 2496 return -EINVAL; 2497 /* 2498 * See what is needed for reconfiguration 2499 */ 2500 2501 /* Timing fields */ 2502 if (c->t1 != 0 && c->t1 != gsm->t1) 2503 need_restart = 1; 2504 if (c->t2 != 0 && c->t2 != gsm->t2) 2505 need_restart = 1; 2506 if (c->encapsulation != gsm->encoding) 2507 need_restart = 1; 2508 if (c->adaption != gsm->adaption) 2509 need_restart = 1; 2510 /* Requires care */ 2511 if (c->initiator != gsm->initiator) 2512 need_close = 1; 2513 if (c->mru != gsm->mru) 2514 need_restart = 1; 2515 if (c->mtu != gsm->mtu) 2516 need_restart = 1; 2517 2518 /* 2519 * Close down what is needed, restart and initiate the new 2520 * configuration 2521 */ 2522 2523 if (need_close || need_restart) { 2524 int ret; 2525 2526 ret = gsm_disconnect(gsm); 2527 2528 if (ret) 2529 return ret; 2530 } 2531 if (need_restart) 2532 gsm_cleanup_mux(gsm); 2533 2534 gsm->initiator = c->initiator; 2535 gsm->mru = c->mru; 2536 gsm->mtu = c->mtu; 2537 gsm->encoding = c->encapsulation; 2538 gsm->adaption = c->adaption; 2539 gsm->n2 = c->n2; 2540 2541 if (c->i == 1) 2542 gsm->ftype = UIH; 2543 else if (c->i == 2) 2544 gsm->ftype = UI; 2545 2546 if (c->t1) 2547 gsm->t1 = c->t1; 2548 if (c->t2) 2549 gsm->t2 = c->t2; 2550 2551 /* FIXME: We need to separate activation/deactivation from adding 2552 and removing from the mux array */ 2553 if (need_restart) 2554 gsm_activate_mux(gsm); 2555 if (gsm->initiator && need_close) 2556 gsm_dlci_begin_open(gsm->dlci[0]); 2557 return 0; 2558 } 2559 2560 static int gsmld_ioctl(struct tty_struct *tty, struct file *file, 2561 unsigned int cmd, unsigned long arg) 2562 { 2563 struct gsm_config c; 2564 struct gsm_mux *gsm = tty->disc_data; 2565 2566 switch (cmd) { 2567 case GSMIOC_GETCONF: 2568 memset(&c, 0, sizeof(c)); 2569 c.adaption = gsm->adaption; 2570 c.encapsulation = gsm->encoding; 2571 c.initiator = gsm->initiator; 2572 c.t1 = gsm->t1; 2573 c.t2 = gsm->t2; 2574 c.t3 = 0; /* Not supported */ 2575 c.n2 = gsm->n2; 2576 if (gsm->ftype == UIH) 2577 c.i = 1; 2578 else 2579 c.i = 2; 2580 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i); 2581 c.mru = gsm->mru; 2582 c.mtu = gsm->mtu; 2583 c.k = 0; 2584 if (copy_to_user((void *)arg, &c, sizeof(c))) 2585 return -EFAULT; 2586 return 0; 2587 case GSMIOC_SETCONF: 2588 if (copy_from_user(&c, (void *)arg, sizeof(c))) 2589 return -EFAULT; 2590 return gsmld_config(tty, gsm, &c); 2591 default: 2592 return n_tty_ioctl_helper(tty, file, cmd, arg); 2593 } 2594 } 2595 2596 #ifdef CONFIG_COMPAT 2597 static long gsmld_compat_ioctl(struct tty_struct *tty, struct file *file, 2598 unsigned int cmd, unsigned long arg) 2599 { 2600 return gsmld_ioctl(tty, file, cmd, arg); 2601 } 2602 #endif 2603 2604 /* 2605 * Network interface 2606 * 2607 */ 2608 2609 static int gsm_mux_net_open(struct net_device *net) 2610 { 2611 pr_debug("%s called\n", __func__); 2612 netif_start_queue(net); 2613 return 0; 2614 } 2615 2616 static int gsm_mux_net_close(struct net_device *net) 2617 { 2618 netif_stop_queue(net); 2619 return 0; 2620 } 2621 2622 static void dlci_net_free(struct gsm_dlci *dlci) 2623 { 2624 if (!dlci->net) { 2625 WARN_ON(1); 2626 return; 2627 } 2628 dlci->adaption = dlci->prev_adaption; 2629 dlci->data = dlci->prev_data; 2630 free_netdev(dlci->net); 2631 dlci->net = NULL; 2632 } 2633 static void net_free(struct kref *ref) 2634 { 2635 struct gsm_mux_net *mux_net; 2636 struct gsm_dlci *dlci; 2637 2638 mux_net = container_of(ref, struct gsm_mux_net, ref); 2639 dlci = mux_net->dlci; 2640 2641 if (dlci->net) { 2642 unregister_netdev(dlci->net); 2643 dlci_net_free(dlci); 2644 } 2645 } 2646 2647 static inline void muxnet_get(struct gsm_mux_net *mux_net) 2648 { 2649 kref_get(&mux_net->ref); 2650 } 2651 2652 static inline void muxnet_put(struct gsm_mux_net *mux_net) 2653 { 2654 kref_put(&mux_net->ref, net_free); 2655 } 2656 2657 static int gsm_mux_net_start_xmit(struct sk_buff *skb, 2658 struct net_device *net) 2659 { 2660 struct gsm_mux_net *mux_net = netdev_priv(net); 2661 struct gsm_dlci *dlci = mux_net->dlci; 2662 muxnet_get(mux_net); 2663 2664 skb_queue_head(&dlci->skb_list, skb); 2665 net->stats.tx_packets++; 2666 net->stats.tx_bytes += skb->len; 2667 gsm_dlci_data_kick(dlci); 2668 /* And tell the kernel when the last transmit started. */ 2669 netif_trans_update(net); 2670 muxnet_put(mux_net); 2671 return NETDEV_TX_OK; 2672 } 2673 2674 /* called when a packet did not ack after watchdogtimeout */ 2675 static void gsm_mux_net_tx_timeout(struct net_device *net) 2676 { 2677 /* Tell syslog we are hosed. */ 2678 dev_dbg(&net->dev, "Tx timed out.\n"); 2679 2680 /* Update statistics */ 2681 net->stats.tx_errors++; 2682 } 2683 2684 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci, 2685 unsigned char *in_buf, int size) 2686 { 2687 struct net_device *net = dlci->net; 2688 struct sk_buff *skb; 2689 struct gsm_mux_net *mux_net = netdev_priv(net); 2690 muxnet_get(mux_net); 2691 2692 /* Allocate an sk_buff */ 2693 skb = dev_alloc_skb(size + NET_IP_ALIGN); 2694 if (!skb) { 2695 /* We got no receive buffer. */ 2696 net->stats.rx_dropped++; 2697 muxnet_put(mux_net); 2698 return; 2699 } 2700 skb_reserve(skb, NET_IP_ALIGN); 2701 skb_put_data(skb, in_buf, size); 2702 2703 skb->dev = net; 2704 skb->protocol = htons(ETH_P_IP); 2705 2706 /* Ship it off to the kernel */ 2707 netif_rx(skb); 2708 2709 /* update out statistics */ 2710 net->stats.rx_packets++; 2711 net->stats.rx_bytes += size; 2712 muxnet_put(mux_net); 2713 return; 2714 } 2715 2716 static void gsm_mux_net_init(struct net_device *net) 2717 { 2718 static const struct net_device_ops gsm_netdev_ops = { 2719 .ndo_open = gsm_mux_net_open, 2720 .ndo_stop = gsm_mux_net_close, 2721 .ndo_start_xmit = gsm_mux_net_start_xmit, 2722 .ndo_tx_timeout = gsm_mux_net_tx_timeout, 2723 }; 2724 2725 net->netdev_ops = &gsm_netdev_ops; 2726 2727 /* fill in the other fields */ 2728 net->watchdog_timeo = GSM_NET_TX_TIMEOUT; 2729 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 2730 net->type = ARPHRD_NONE; 2731 net->tx_queue_len = 10; 2732 } 2733 2734 2735 /* caller holds the dlci mutex */ 2736 static void gsm_destroy_network(struct gsm_dlci *dlci) 2737 { 2738 struct gsm_mux_net *mux_net; 2739 2740 pr_debug("destroy network interface"); 2741 if (!dlci->net) 2742 return; 2743 mux_net = netdev_priv(dlci->net); 2744 muxnet_put(mux_net); 2745 } 2746 2747 2748 /* caller holds the dlci mutex */ 2749 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc) 2750 { 2751 char *netname; 2752 int retval = 0; 2753 struct net_device *net; 2754 struct gsm_mux_net *mux_net; 2755 2756 if (!capable(CAP_NET_ADMIN)) 2757 return -EPERM; 2758 2759 /* Already in a non tty mode */ 2760 if (dlci->adaption > 2) 2761 return -EBUSY; 2762 2763 if (nc->protocol != htons(ETH_P_IP)) 2764 return -EPROTONOSUPPORT; 2765 2766 if (nc->adaption != 3 && nc->adaption != 4) 2767 return -EPROTONOSUPPORT; 2768 2769 pr_debug("create network interface"); 2770 2771 netname = "gsm%d"; 2772 if (nc->if_name[0] != '\0') 2773 netname = nc->if_name; 2774 net = alloc_netdev(sizeof(struct gsm_mux_net), netname, 2775 NET_NAME_UNKNOWN, gsm_mux_net_init); 2776 if (!net) { 2777 pr_err("alloc_netdev failed"); 2778 return -ENOMEM; 2779 } 2780 net->mtu = dlci->gsm->mtu; 2781 net->min_mtu = 8; 2782 net->max_mtu = dlci->gsm->mtu; 2783 mux_net = netdev_priv(net); 2784 mux_net->dlci = dlci; 2785 kref_init(&mux_net->ref); 2786 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */ 2787 2788 /* reconfigure dlci for network */ 2789 dlci->prev_adaption = dlci->adaption; 2790 dlci->prev_data = dlci->data; 2791 dlci->adaption = nc->adaption; 2792 dlci->data = gsm_mux_rx_netchar; 2793 dlci->net = net; 2794 2795 pr_debug("register netdev"); 2796 retval = register_netdev(net); 2797 if (retval) { 2798 pr_err("network register fail %d\n", retval); 2799 dlci_net_free(dlci); 2800 return retval; 2801 } 2802 return net->ifindex; /* return network index */ 2803 } 2804 2805 /* Line discipline for real tty */ 2806 static struct tty_ldisc_ops tty_ldisc_packet = { 2807 .owner = THIS_MODULE, 2808 .magic = TTY_LDISC_MAGIC, 2809 .name = "n_gsm", 2810 .open = gsmld_open, 2811 .close = gsmld_close, 2812 .flush_buffer = gsmld_flush_buffer, 2813 .read = gsmld_read, 2814 .write = gsmld_write, 2815 #ifdef CONFIG_COMPAT 2816 .compat_ioctl = gsmld_compat_ioctl, 2817 #endif 2818 .ioctl = gsmld_ioctl, 2819 .poll = gsmld_poll, 2820 .receive_buf = gsmld_receive_buf, 2821 .write_wakeup = gsmld_write_wakeup 2822 }; 2823 2824 /* 2825 * Virtual tty side 2826 */ 2827 2828 #define TX_SIZE 512 2829 2830 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) 2831 { 2832 u8 modembits[5]; 2833 struct gsm_control *ctrl; 2834 int len = 2; 2835 2836 if (brk) 2837 len++; 2838 2839 modembits[0] = len << 1 | EA; /* Data bytes */ 2840 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */ 2841 modembits[2] = gsm_encode_modem(dlci) << 1 | EA; 2842 if (brk) 2843 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */ 2844 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1); 2845 if (ctrl == NULL) 2846 return -ENOMEM; 2847 return gsm_control_wait(dlci->gsm, ctrl); 2848 } 2849 2850 static int gsm_carrier_raised(struct tty_port *port) 2851 { 2852 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2853 /* Not yet open so no carrier info */ 2854 if (dlci->state != DLCI_OPEN) 2855 return 0; 2856 if (debug & 2) 2857 return 1; 2858 return dlci->modem_rx & TIOCM_CD; 2859 } 2860 2861 static void gsm_dtr_rts(struct tty_port *port, int onoff) 2862 { 2863 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2864 unsigned int modem_tx = dlci->modem_tx; 2865 if (onoff) 2866 modem_tx |= TIOCM_DTR | TIOCM_RTS; 2867 else 2868 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); 2869 if (modem_tx != dlci->modem_tx) { 2870 dlci->modem_tx = modem_tx; 2871 gsmtty_modem_update(dlci, 0); 2872 } 2873 } 2874 2875 static const struct tty_port_operations gsm_port_ops = { 2876 .carrier_raised = gsm_carrier_raised, 2877 .dtr_rts = gsm_dtr_rts, 2878 .destruct = gsm_dlci_free, 2879 }; 2880 2881 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty) 2882 { 2883 struct gsm_mux *gsm; 2884 struct gsm_dlci *dlci; 2885 unsigned int line = tty->index; 2886 unsigned int mux = line >> 6; 2887 bool alloc = false; 2888 int ret; 2889 2890 line = line & 0x3F; 2891 2892 if (mux >= MAX_MUX) 2893 return -ENXIO; 2894 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */ 2895 if (gsm_mux[mux] == NULL) 2896 return -EUNATCH; 2897 if (line == 0 || line > 61) /* 62/63 reserved */ 2898 return -ECHRNG; 2899 gsm = gsm_mux[mux]; 2900 if (gsm->dead) 2901 return -EL2HLT; 2902 /* If DLCI 0 is not yet fully open return an error. 2903 This is ok from a locking 2904 perspective as we don't have to worry about this 2905 if DLCI0 is lost */ 2906 mutex_lock(&gsm->mutex); 2907 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) { 2908 mutex_unlock(&gsm->mutex); 2909 return -EL2NSYNC; 2910 } 2911 dlci = gsm->dlci[line]; 2912 if (dlci == NULL) { 2913 alloc = true; 2914 dlci = gsm_dlci_alloc(gsm, line); 2915 } 2916 if (dlci == NULL) { 2917 mutex_unlock(&gsm->mutex); 2918 return -ENOMEM; 2919 } 2920 ret = tty_port_install(&dlci->port, driver, tty); 2921 if (ret) { 2922 if (alloc) 2923 dlci_put(dlci); 2924 mutex_unlock(&gsm->mutex); 2925 return ret; 2926 } 2927 2928 dlci_get(dlci); 2929 dlci_get(gsm->dlci[0]); 2930 mux_get(gsm); 2931 tty->driver_data = dlci; 2932 mutex_unlock(&gsm->mutex); 2933 2934 return 0; 2935 } 2936 2937 static int gsmtty_open(struct tty_struct *tty, struct file *filp) 2938 { 2939 struct gsm_dlci *dlci = tty->driver_data; 2940 struct tty_port *port = &dlci->port; 2941 2942 port->count++; 2943 tty_port_tty_set(port, tty); 2944 2945 dlci->modem_rx = 0; 2946 /* We could in theory open and close before we wait - eg if we get 2947 a DM straight back. This is ok as that will have caused a hangup */ 2948 tty_port_set_initialized(port, 1); 2949 /* Start sending off SABM messages */ 2950 gsm_dlci_begin_open(dlci); 2951 /* And wait for virtual carrier */ 2952 return tty_port_block_til_ready(port, tty, filp); 2953 } 2954 2955 static void gsmtty_close(struct tty_struct *tty, struct file *filp) 2956 { 2957 struct gsm_dlci *dlci = tty->driver_data; 2958 struct gsm_mux *gsm; 2959 2960 if (dlci == NULL) 2961 return; 2962 if (dlci->state == DLCI_CLOSED) 2963 return; 2964 mutex_lock(&dlci->mutex); 2965 gsm_destroy_network(dlci); 2966 mutex_unlock(&dlci->mutex); 2967 gsm = dlci->gsm; 2968 if (tty_port_close_start(&dlci->port, tty, filp) == 0) 2969 return; 2970 gsm_dlci_begin_close(dlci); 2971 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty)) 2972 tty_port_lower_dtr_rts(&dlci->port); 2973 tty_port_close_end(&dlci->port, tty); 2974 tty_port_tty_set(&dlci->port, NULL); 2975 return; 2976 } 2977 2978 static void gsmtty_hangup(struct tty_struct *tty) 2979 { 2980 struct gsm_dlci *dlci = tty->driver_data; 2981 if (dlci->state == DLCI_CLOSED) 2982 return; 2983 tty_port_hangup(&dlci->port); 2984 gsm_dlci_begin_close(dlci); 2985 } 2986 2987 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf, 2988 int len) 2989 { 2990 int sent; 2991 struct gsm_dlci *dlci = tty->driver_data; 2992 if (dlci->state == DLCI_CLOSED) 2993 return -EINVAL; 2994 /* Stuff the bytes into the fifo queue */ 2995 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock); 2996 /* Need to kick the channel */ 2997 gsm_dlci_data_kick(dlci); 2998 return sent; 2999 } 3000 3001 static int gsmtty_write_room(struct tty_struct *tty) 3002 { 3003 struct gsm_dlci *dlci = tty->driver_data; 3004 if (dlci->state == DLCI_CLOSED) 3005 return -EINVAL; 3006 return TX_SIZE - kfifo_len(dlci->fifo); 3007 } 3008 3009 static int gsmtty_chars_in_buffer(struct tty_struct *tty) 3010 { 3011 struct gsm_dlci *dlci = tty->driver_data; 3012 if (dlci->state == DLCI_CLOSED) 3013 return -EINVAL; 3014 return kfifo_len(dlci->fifo); 3015 } 3016 3017 static void gsmtty_flush_buffer(struct tty_struct *tty) 3018 { 3019 struct gsm_dlci *dlci = tty->driver_data; 3020 if (dlci->state == DLCI_CLOSED) 3021 return; 3022 /* Caution needed: If we implement reliable transport classes 3023 then the data being transmitted can't simply be junked once 3024 it has first hit the stack. Until then we can just blow it 3025 away */ 3026 kfifo_reset(dlci->fifo); 3027 /* Need to unhook this DLCI from the transmit queue logic */ 3028 } 3029 3030 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout) 3031 { 3032 /* The FIFO handles the queue so the kernel will do the right 3033 thing waiting on chars_in_buffer before calling us. No work 3034 to do here */ 3035 } 3036 3037 static int gsmtty_tiocmget(struct tty_struct *tty) 3038 { 3039 struct gsm_dlci *dlci = tty->driver_data; 3040 if (dlci->state == DLCI_CLOSED) 3041 return -EINVAL; 3042 return dlci->modem_rx; 3043 } 3044 3045 static int gsmtty_tiocmset(struct tty_struct *tty, 3046 unsigned int set, unsigned int clear) 3047 { 3048 struct gsm_dlci *dlci = tty->driver_data; 3049 unsigned int modem_tx = dlci->modem_tx; 3050 3051 if (dlci->state == DLCI_CLOSED) 3052 return -EINVAL; 3053 modem_tx &= ~clear; 3054 modem_tx |= set; 3055 3056 if (modem_tx != dlci->modem_tx) { 3057 dlci->modem_tx = modem_tx; 3058 return gsmtty_modem_update(dlci, 0); 3059 } 3060 return 0; 3061 } 3062 3063 3064 static int gsmtty_ioctl(struct tty_struct *tty, 3065 unsigned int cmd, unsigned long arg) 3066 { 3067 struct gsm_dlci *dlci = tty->driver_data; 3068 struct gsm_netconfig nc; 3069 int index; 3070 3071 if (dlci->state == DLCI_CLOSED) 3072 return -EINVAL; 3073 switch (cmd) { 3074 case GSMIOC_ENABLE_NET: 3075 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc))) 3076 return -EFAULT; 3077 nc.if_name[IFNAMSIZ-1] = '\0'; 3078 /* return net interface index or error code */ 3079 mutex_lock(&dlci->mutex); 3080 index = gsm_create_network(dlci, &nc); 3081 mutex_unlock(&dlci->mutex); 3082 if (copy_to_user((void __user *)arg, &nc, sizeof(nc))) 3083 return -EFAULT; 3084 return index; 3085 case GSMIOC_DISABLE_NET: 3086 if (!capable(CAP_NET_ADMIN)) 3087 return -EPERM; 3088 mutex_lock(&dlci->mutex); 3089 gsm_destroy_network(dlci); 3090 mutex_unlock(&dlci->mutex); 3091 return 0; 3092 default: 3093 return -ENOIOCTLCMD; 3094 } 3095 } 3096 3097 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old) 3098 { 3099 struct gsm_dlci *dlci = tty->driver_data; 3100 if (dlci->state == DLCI_CLOSED) 3101 return; 3102 /* For the moment its fixed. In actual fact the speed information 3103 for the virtual channel can be propogated in both directions by 3104 the RPN control message. This however rapidly gets nasty as we 3105 then have to remap modem signals each way according to whether 3106 our virtual cable is null modem etc .. */ 3107 tty_termios_copy_hw(&tty->termios, old); 3108 } 3109 3110 static void gsmtty_throttle(struct tty_struct *tty) 3111 { 3112 struct gsm_dlci *dlci = tty->driver_data; 3113 if (dlci->state == DLCI_CLOSED) 3114 return; 3115 if (C_CRTSCTS(tty)) 3116 dlci->modem_tx &= ~TIOCM_DTR; 3117 dlci->throttled = 1; 3118 /* Send an MSC with DTR cleared */ 3119 gsmtty_modem_update(dlci, 0); 3120 } 3121 3122 static void gsmtty_unthrottle(struct tty_struct *tty) 3123 { 3124 struct gsm_dlci *dlci = tty->driver_data; 3125 if (dlci->state == DLCI_CLOSED) 3126 return; 3127 if (C_CRTSCTS(tty)) 3128 dlci->modem_tx |= TIOCM_DTR; 3129 dlci->throttled = 0; 3130 /* Send an MSC with DTR set */ 3131 gsmtty_modem_update(dlci, 0); 3132 } 3133 3134 static int gsmtty_break_ctl(struct tty_struct *tty, int state) 3135 { 3136 struct gsm_dlci *dlci = tty->driver_data; 3137 int encode = 0; /* Off */ 3138 if (dlci->state == DLCI_CLOSED) 3139 return -EINVAL; 3140 3141 if (state == -1) /* "On indefinitely" - we can't encode this 3142 properly */ 3143 encode = 0x0F; 3144 else if (state > 0) { 3145 encode = state / 200; /* mS to encoding */ 3146 if (encode > 0x0F) 3147 encode = 0x0F; /* Best effort */ 3148 } 3149 return gsmtty_modem_update(dlci, encode); 3150 } 3151 3152 static void gsmtty_cleanup(struct tty_struct *tty) 3153 { 3154 struct gsm_dlci *dlci = tty->driver_data; 3155 struct gsm_mux *gsm = dlci->gsm; 3156 3157 dlci_put(dlci); 3158 dlci_put(gsm->dlci[0]); 3159 mux_put(gsm); 3160 } 3161 3162 /* Virtual ttys for the demux */ 3163 static const struct tty_operations gsmtty_ops = { 3164 .install = gsmtty_install, 3165 .open = gsmtty_open, 3166 .close = gsmtty_close, 3167 .write = gsmtty_write, 3168 .write_room = gsmtty_write_room, 3169 .chars_in_buffer = gsmtty_chars_in_buffer, 3170 .flush_buffer = gsmtty_flush_buffer, 3171 .ioctl = gsmtty_ioctl, 3172 .throttle = gsmtty_throttle, 3173 .unthrottle = gsmtty_unthrottle, 3174 .set_termios = gsmtty_set_termios, 3175 .hangup = gsmtty_hangup, 3176 .wait_until_sent = gsmtty_wait_until_sent, 3177 .tiocmget = gsmtty_tiocmget, 3178 .tiocmset = gsmtty_tiocmset, 3179 .break_ctl = gsmtty_break_ctl, 3180 .cleanup = gsmtty_cleanup, 3181 }; 3182 3183 3184 3185 static int __init gsm_init(void) 3186 { 3187 /* Fill in our line protocol discipline, and register it */ 3188 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet); 3189 if (status != 0) { 3190 pr_err("n_gsm: can't register line discipline (err = %d)\n", 3191 status); 3192 return status; 3193 } 3194 3195 gsm_tty_driver = alloc_tty_driver(256); 3196 if (!gsm_tty_driver) { 3197 tty_unregister_ldisc(N_GSM0710); 3198 pr_err("gsm_init: tty allocation failed.\n"); 3199 return -EINVAL; 3200 } 3201 gsm_tty_driver->driver_name = "gsmtty"; 3202 gsm_tty_driver->name = "gsmtty"; 3203 gsm_tty_driver->major = 0; /* Dynamic */ 3204 gsm_tty_driver->minor_start = 0; 3205 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; 3206 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL; 3207 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV 3208 | TTY_DRIVER_HARDWARE_BREAK; 3209 gsm_tty_driver->init_termios = tty_std_termios; 3210 /* Fixme */ 3211 gsm_tty_driver->init_termios.c_lflag &= ~ECHO; 3212 tty_set_operations(gsm_tty_driver, &gsmtty_ops); 3213 3214 spin_lock_init(&gsm_mux_lock); 3215 3216 if (tty_register_driver(gsm_tty_driver)) { 3217 put_tty_driver(gsm_tty_driver); 3218 tty_unregister_ldisc(N_GSM0710); 3219 pr_err("gsm_init: tty registration failed.\n"); 3220 return -EBUSY; 3221 } 3222 pr_debug("gsm_init: loaded as %d,%d.\n", 3223 gsm_tty_driver->major, gsm_tty_driver->minor_start); 3224 return 0; 3225 } 3226 3227 static void __exit gsm_exit(void) 3228 { 3229 int status = tty_unregister_ldisc(N_GSM0710); 3230 if (status != 0) 3231 pr_err("n_gsm: can't unregister line discipline (err = %d)\n", 3232 status); 3233 tty_unregister_driver(gsm_tty_driver); 3234 put_tty_driver(gsm_tty_driver); 3235 } 3236 3237 module_init(gsm_init); 3238 module_exit(gsm_exit); 3239 3240 3241 MODULE_LICENSE("GPL"); 3242 MODULE_ALIAS_LDISC(N_GSM0710); 3243