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