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, const u8 *data, int len); 147 void (*prev_data)(struct gsm_dlci *dlci, const 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, const u8 *data, 992 int dlen) 993 { 994 struct gsm_msg *msg; 995 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype); 996 if (msg == NULL) 997 return; 998 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */ 999 msg->data[1] = (dlen << 1) | EA; 1000 memcpy(msg->data + 2, data, dlen); 1001 gsm_data_queue(gsm->dlci[0], msg); 1002 } 1003 1004 /** 1005 * gsm_process_modem - process received modem status 1006 * @tty: virtual tty bound to the DLCI 1007 * @dlci: DLCI to affect 1008 * @modem: modem bits (full EA) 1009 * 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, const 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 const 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, const u8 *data, int clen) 1138 { 1139 struct tty_port *port; 1140 unsigned int addr = 0; 1141 u8 bits; 1142 int len = clen; 1143 const 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 const 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 const 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, const 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 case 4: /* Packetised interruptible data */ 1569 break; 1570 case 3: /* Packetised uininterruptible voice/data */ 1571 break; 1572 case 2: /* Asynchronous serial with line state in each frame */ 1573 while (gsm_read_ea(&modem, *data++) == 0) { 1574 len--; 1575 if (len == 0) 1576 return; 1577 } 1578 tty = tty_port_tty_get(port); 1579 if (tty) { 1580 gsm_process_modem(tty, dlci, modem, clen); 1581 tty_kref_put(tty); 1582 } 1583 /* Fall through */ 1584 case 1: /* Line state will go via DLCI 0 controls only */ 1585 default: 1586 tty_insert_flip_string(port, data, len); 1587 tty_flip_buffer_push(port); 1588 } 1589 } 1590 1591 /** 1592 * gsm_dlci_control - data arrived on control channel 1593 * @dlci: channel 1594 * @data: block of bytes received 1595 * @len: length of received block 1596 * 1597 * A UI or UIH frame has arrived which contains data for DLCI 0 the 1598 * control channel. This should contain a command EA followed by 1599 * control data bytes. The command EA contains a command/response bit 1600 * and we divide up the work accordingly. 1601 */ 1602 1603 static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len) 1604 { 1605 /* See what command is involved */ 1606 unsigned int command = 0; 1607 while (len-- > 0) { 1608 if (gsm_read_ea(&command, *data++) == 1) { 1609 int clen = *data++; 1610 len--; 1611 /* FIXME: this is properly an EA */ 1612 clen >>= 1; 1613 /* Malformed command ? */ 1614 if (clen > len) 1615 return; 1616 if (command & 1) 1617 gsm_control_message(dlci->gsm, command, 1618 data, clen); 1619 else 1620 gsm_control_response(dlci->gsm, command, 1621 data, clen); 1622 return; 1623 } 1624 } 1625 } 1626 1627 /* 1628 * Allocate/Free DLCI channels 1629 */ 1630 1631 /** 1632 * gsm_dlci_alloc - allocate a DLCI 1633 * @gsm: GSM mux 1634 * @addr: address of the DLCI 1635 * 1636 * Allocate and install a new DLCI object into the GSM mux. 1637 * 1638 * FIXME: review locking races 1639 */ 1640 1641 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr) 1642 { 1643 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC); 1644 if (dlci == NULL) 1645 return NULL; 1646 spin_lock_init(&dlci->lock); 1647 mutex_init(&dlci->mutex); 1648 dlci->fifo = &dlci->_fifo; 1649 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) { 1650 kfree(dlci); 1651 return NULL; 1652 } 1653 1654 skb_queue_head_init(&dlci->skb_list); 1655 timer_setup(&dlci->t1, gsm_dlci_t1, 0); 1656 tty_port_init(&dlci->port); 1657 dlci->port.ops = &gsm_port_ops; 1658 dlci->gsm = gsm; 1659 dlci->addr = addr; 1660 dlci->adaption = gsm->adaption; 1661 dlci->state = DLCI_CLOSED; 1662 if (addr) 1663 dlci->data = gsm_dlci_data; 1664 else 1665 dlci->data = gsm_dlci_command; 1666 gsm->dlci[addr] = dlci; 1667 return dlci; 1668 } 1669 1670 /** 1671 * gsm_dlci_free - free DLCI 1672 * @dlci: DLCI to free 1673 * 1674 * Free up a DLCI. 1675 * 1676 * Can sleep. 1677 */ 1678 static void gsm_dlci_free(struct tty_port *port) 1679 { 1680 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 1681 1682 del_timer_sync(&dlci->t1); 1683 dlci->gsm->dlci[dlci->addr] = NULL; 1684 kfifo_free(dlci->fifo); 1685 while ((dlci->skb = skb_dequeue(&dlci->skb_list))) 1686 dev_kfree_skb(dlci->skb); 1687 kfree(dlci); 1688 } 1689 1690 static inline void dlci_get(struct gsm_dlci *dlci) 1691 { 1692 tty_port_get(&dlci->port); 1693 } 1694 1695 static inline void dlci_put(struct gsm_dlci *dlci) 1696 { 1697 tty_port_put(&dlci->port); 1698 } 1699 1700 static void gsm_destroy_network(struct gsm_dlci *dlci); 1701 1702 /** 1703 * gsm_dlci_release - release DLCI 1704 * @dlci: DLCI to destroy 1705 * 1706 * Release a DLCI. Actual free is deferred until either 1707 * mux is closed or tty is closed - whichever is last. 1708 * 1709 * Can sleep. 1710 */ 1711 static void gsm_dlci_release(struct gsm_dlci *dlci) 1712 { 1713 struct tty_struct *tty = tty_port_tty_get(&dlci->port); 1714 if (tty) { 1715 mutex_lock(&dlci->mutex); 1716 gsm_destroy_network(dlci); 1717 mutex_unlock(&dlci->mutex); 1718 1719 tty_hangup(tty); 1720 1721 tty_port_tty_set(&dlci->port, NULL); 1722 tty_kref_put(tty); 1723 } 1724 dlci->state = DLCI_CLOSED; 1725 dlci_put(dlci); 1726 } 1727 1728 /* 1729 * LAPBish link layer logic 1730 */ 1731 1732 /** 1733 * gsm_queue - a GSM frame is ready to process 1734 * @gsm: pointer to our gsm mux 1735 * 1736 * At this point in time a frame has arrived and been demangled from 1737 * the line encoding. All the differences between the encodings have 1738 * been handled below us and the frame is unpacked into the structures. 1739 * The fcs holds the header FCS but any data FCS must be added here. 1740 */ 1741 1742 static void gsm_queue(struct gsm_mux *gsm) 1743 { 1744 struct gsm_dlci *dlci; 1745 u8 cr; 1746 int address; 1747 /* We have to sneak a look at the packet body to do the FCS. 1748 A somewhat layering violation in the spec */ 1749 1750 if ((gsm->control & ~PF) == UI) 1751 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len); 1752 if (gsm->encoding == 0) { 1753 /* WARNING: gsm->received_fcs is used for 1754 gsm->encoding = 0 only. 1755 In this case it contain the last piece of data 1756 required to generate final CRC */ 1757 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs); 1758 } 1759 if (gsm->fcs != GOOD_FCS) { 1760 gsm->bad_fcs++; 1761 if (debug & 4) 1762 pr_debug("BAD FCS %02x\n", gsm->fcs); 1763 return; 1764 } 1765 address = gsm->address >> 1; 1766 if (address >= NUM_DLCI) 1767 goto invalid; 1768 1769 cr = gsm->address & 1; /* C/R bit */ 1770 1771 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len); 1772 1773 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */ 1774 dlci = gsm->dlci[address]; 1775 1776 switch (gsm->control) { 1777 case SABM|PF: 1778 if (cr == 0) 1779 goto invalid; 1780 if (dlci == NULL) 1781 dlci = gsm_dlci_alloc(gsm, address); 1782 if (dlci == NULL) 1783 return; 1784 if (dlci->dead) 1785 gsm_response(gsm, address, DM); 1786 else { 1787 gsm_response(gsm, address, UA); 1788 gsm_dlci_open(dlci); 1789 } 1790 break; 1791 case DISC|PF: 1792 if (cr == 0) 1793 goto invalid; 1794 if (dlci == NULL || dlci->state == DLCI_CLOSED) { 1795 gsm_response(gsm, address, DM); 1796 return; 1797 } 1798 /* Real close complete */ 1799 gsm_response(gsm, address, UA); 1800 gsm_dlci_close(dlci); 1801 break; 1802 case UA: 1803 case UA|PF: 1804 if (cr == 0 || dlci == NULL) 1805 break; 1806 switch (dlci->state) { 1807 case DLCI_CLOSING: 1808 gsm_dlci_close(dlci); 1809 break; 1810 case DLCI_OPENING: 1811 gsm_dlci_open(dlci); 1812 break; 1813 } 1814 break; 1815 case DM: /* DM can be valid unsolicited */ 1816 case DM|PF: 1817 if (cr) 1818 goto invalid; 1819 if (dlci == NULL) 1820 return; 1821 gsm_dlci_close(dlci); 1822 break; 1823 case UI: 1824 case UI|PF: 1825 case UIH: 1826 case UIH|PF: 1827 #if 0 1828 if (cr) 1829 goto invalid; 1830 #endif 1831 if (dlci == NULL || dlci->state != DLCI_OPEN) { 1832 gsm_command(gsm, address, DM|PF); 1833 return; 1834 } 1835 dlci->data(dlci, gsm->buf, gsm->len); 1836 break; 1837 default: 1838 goto invalid; 1839 } 1840 return; 1841 invalid: 1842 gsm->malformed++; 1843 return; 1844 } 1845 1846 1847 /** 1848 * gsm0_receive - perform processing for non-transparency 1849 * @gsm: gsm data for this ldisc instance 1850 * @c: character 1851 * 1852 * Receive bytes in gsm mode 0 1853 */ 1854 1855 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) 1856 { 1857 unsigned int len; 1858 1859 switch (gsm->state) { 1860 case GSM_SEARCH: /* SOF marker */ 1861 if (c == GSM0_SOF) { 1862 gsm->state = GSM_ADDRESS; 1863 gsm->address = 0; 1864 gsm->len = 0; 1865 gsm->fcs = INIT_FCS; 1866 } 1867 break; 1868 case GSM_ADDRESS: /* Address EA */ 1869 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1870 if (gsm_read_ea(&gsm->address, c)) 1871 gsm->state = GSM_CONTROL; 1872 break; 1873 case GSM_CONTROL: /* Control Byte */ 1874 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1875 gsm->control = c; 1876 gsm->state = GSM_LEN0; 1877 break; 1878 case GSM_LEN0: /* Length EA */ 1879 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1880 if (gsm_read_ea(&gsm->len, c)) { 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 } 1893 gsm->state = GSM_LEN1; 1894 break; 1895 case GSM_LEN1: 1896 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1897 len = c; 1898 gsm->len |= len << 7; 1899 if (gsm->len > gsm->mru) { 1900 gsm->bad_size++; 1901 gsm->state = GSM_SEARCH; 1902 break; 1903 } 1904 gsm->count = 0; 1905 if (!gsm->len) 1906 gsm->state = GSM_FCS; 1907 else 1908 gsm->state = GSM_DATA; 1909 break; 1910 case GSM_DATA: /* Data */ 1911 gsm->buf[gsm->count++] = c; 1912 if (gsm->count == gsm->len) 1913 gsm->state = GSM_FCS; 1914 break; 1915 case GSM_FCS: /* FCS follows the packet */ 1916 gsm->received_fcs = c; 1917 gsm_queue(gsm); 1918 gsm->state = GSM_SSOF; 1919 break; 1920 case GSM_SSOF: 1921 if (c == GSM0_SOF) { 1922 gsm->state = GSM_SEARCH; 1923 break; 1924 } 1925 break; 1926 } 1927 } 1928 1929 /** 1930 * gsm1_receive - perform processing for non-transparency 1931 * @gsm: gsm data for this ldisc instance 1932 * @c: character 1933 * 1934 * Receive bytes in mode 1 (Advanced option) 1935 */ 1936 1937 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c) 1938 { 1939 if (c == GSM1_SOF) { 1940 /* EOF is only valid in frame if we have got to the data state 1941 and received at least one byte (the FCS) */ 1942 if (gsm->state == GSM_DATA && gsm->count) { 1943 /* Extract the FCS */ 1944 gsm->count--; 1945 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]); 1946 gsm->len = gsm->count; 1947 gsm_queue(gsm); 1948 gsm->state = GSM_START; 1949 return; 1950 } 1951 /* Any partial frame was a runt so go back to start */ 1952 if (gsm->state != GSM_START) { 1953 gsm->malformed++; 1954 gsm->state = GSM_START; 1955 } 1956 /* A SOF in GSM_START means we are still reading idling or 1957 framing bytes */ 1958 return; 1959 } 1960 1961 if (c == GSM1_ESCAPE) { 1962 gsm->escape = 1; 1963 return; 1964 } 1965 1966 /* Only an unescaped SOF gets us out of GSM search */ 1967 if (gsm->state == GSM_SEARCH) 1968 return; 1969 1970 if (gsm->escape) { 1971 c ^= GSM1_ESCAPE_BITS; 1972 gsm->escape = 0; 1973 } 1974 switch (gsm->state) { 1975 case GSM_START: /* First byte after SOF */ 1976 gsm->address = 0; 1977 gsm->state = GSM_ADDRESS; 1978 gsm->fcs = INIT_FCS; 1979 /* Fall through */ 1980 case GSM_ADDRESS: /* Address continuation */ 1981 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1982 if (gsm_read_ea(&gsm->address, c)) 1983 gsm->state = GSM_CONTROL; 1984 break; 1985 case GSM_CONTROL: /* Control Byte */ 1986 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1987 gsm->control = c; 1988 gsm->count = 0; 1989 gsm->state = GSM_DATA; 1990 break; 1991 case GSM_DATA: /* Data */ 1992 if (gsm->count > gsm->mru) { /* Allow one for the FCS */ 1993 gsm->state = GSM_OVERRUN; 1994 gsm->bad_size++; 1995 } else 1996 gsm->buf[gsm->count++] = c; 1997 break; 1998 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */ 1999 break; 2000 } 2001 } 2002 2003 /** 2004 * gsm_error - handle tty error 2005 * @gsm: ldisc data 2006 * @data: byte received (may be invalid) 2007 * @flag: error received 2008 * 2009 * Handle an error in the receipt of data for a frame. Currently we just 2010 * go back to hunting for a SOF. 2011 * 2012 * FIXME: better diagnostics ? 2013 */ 2014 2015 static void gsm_error(struct gsm_mux *gsm, 2016 unsigned char data, unsigned char flag) 2017 { 2018 gsm->state = GSM_SEARCH; 2019 gsm->io_error++; 2020 } 2021 2022 static int gsm_disconnect(struct gsm_mux *gsm) 2023 { 2024 struct gsm_dlci *dlci = gsm->dlci[0]; 2025 struct gsm_control *gc; 2026 2027 if (!dlci) 2028 return 0; 2029 2030 /* In theory disconnecting DLCI 0 is sufficient but for some 2031 modems this is apparently not the case. */ 2032 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0); 2033 if (gc) 2034 gsm_control_wait(gsm, gc); 2035 2036 del_timer_sync(&gsm->t2_timer); 2037 /* Now we are sure T2 has stopped */ 2038 2039 gsm_dlci_begin_close(dlci); 2040 wait_event_interruptible(gsm->event, 2041 dlci->state == DLCI_CLOSED); 2042 2043 if (signal_pending(current)) 2044 return -EINTR; 2045 2046 return 0; 2047 } 2048 2049 /** 2050 * gsm_cleanup_mux - generic GSM protocol cleanup 2051 * @gsm: our mux 2052 * 2053 * Clean up the bits of the mux which are the same for all framing 2054 * protocols. Remove the mux from the mux table, stop all the timers 2055 * and then shut down each device hanging up the channels as we go. 2056 */ 2057 2058 static void gsm_cleanup_mux(struct gsm_mux *gsm) 2059 { 2060 int i; 2061 struct gsm_dlci *dlci = gsm->dlci[0]; 2062 struct gsm_msg *txq, *ntxq; 2063 2064 gsm->dead = 1; 2065 2066 spin_lock(&gsm_mux_lock); 2067 for (i = 0; i < MAX_MUX; i++) { 2068 if (gsm_mux[i] == gsm) { 2069 gsm_mux[i] = NULL; 2070 break; 2071 } 2072 } 2073 spin_unlock(&gsm_mux_lock); 2074 /* open failed before registering => nothing to do */ 2075 if (i == MAX_MUX) 2076 return; 2077 2078 del_timer_sync(&gsm->t2_timer); 2079 /* Now we are sure T2 has stopped */ 2080 if (dlci) 2081 dlci->dead = 1; 2082 2083 /* Free up any link layer users */ 2084 mutex_lock(&gsm->mutex); 2085 for (i = 0; i < NUM_DLCI; i++) 2086 if (gsm->dlci[i]) 2087 gsm_dlci_release(gsm->dlci[i]); 2088 mutex_unlock(&gsm->mutex); 2089 /* Now wipe the queues */ 2090 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list) 2091 kfree(txq); 2092 INIT_LIST_HEAD(&gsm->tx_list); 2093 } 2094 2095 /** 2096 * gsm_activate_mux - generic GSM setup 2097 * @gsm: our mux 2098 * 2099 * Set up the bits of the mux which are the same for all framing 2100 * protocols. Add the mux to the mux table so it can be opened and 2101 * finally kick off connecting to DLCI 0 on the modem. 2102 */ 2103 2104 static int gsm_activate_mux(struct gsm_mux *gsm) 2105 { 2106 struct gsm_dlci *dlci; 2107 int i = 0; 2108 2109 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0); 2110 init_waitqueue_head(&gsm->event); 2111 spin_lock_init(&gsm->control_lock); 2112 spin_lock_init(&gsm->tx_lock); 2113 2114 if (gsm->encoding == 0) 2115 gsm->receive = gsm0_receive; 2116 else 2117 gsm->receive = gsm1_receive; 2118 gsm->error = gsm_error; 2119 2120 spin_lock(&gsm_mux_lock); 2121 for (i = 0; i < MAX_MUX; i++) { 2122 if (gsm_mux[i] == NULL) { 2123 gsm->num = i; 2124 gsm_mux[i] = gsm; 2125 break; 2126 } 2127 } 2128 spin_unlock(&gsm_mux_lock); 2129 if (i == MAX_MUX) 2130 return -EBUSY; 2131 2132 dlci = gsm_dlci_alloc(gsm, 0); 2133 if (dlci == NULL) 2134 return -ENOMEM; 2135 gsm->dead = 0; /* Tty opens are now permissible */ 2136 return 0; 2137 } 2138 2139 /** 2140 * gsm_free_mux - free up a mux 2141 * @mux: mux to free 2142 * 2143 * Dispose of allocated resources for a dead mux 2144 */ 2145 static void gsm_free_mux(struct gsm_mux *gsm) 2146 { 2147 kfree(gsm->txframe); 2148 kfree(gsm->buf); 2149 kfree(gsm); 2150 } 2151 2152 /** 2153 * gsm_free_muxr - free up a mux 2154 * @mux: mux to free 2155 * 2156 * Dispose of allocated resources for a dead mux 2157 */ 2158 static void gsm_free_muxr(struct kref *ref) 2159 { 2160 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref); 2161 gsm_free_mux(gsm); 2162 } 2163 2164 static inline void mux_get(struct gsm_mux *gsm) 2165 { 2166 kref_get(&gsm->ref); 2167 } 2168 2169 static inline void mux_put(struct gsm_mux *gsm) 2170 { 2171 kref_put(&gsm->ref, gsm_free_muxr); 2172 } 2173 2174 static inline unsigned int mux_num_to_base(struct gsm_mux *gsm) 2175 { 2176 return gsm->num * NUM_DLCI; 2177 } 2178 2179 static inline unsigned int mux_line_to_num(unsigned int line) 2180 { 2181 return line / NUM_DLCI; 2182 } 2183 2184 /** 2185 * gsm_alloc_mux - allocate a mux 2186 * 2187 * Creates a new mux ready for activation. 2188 */ 2189 2190 static struct gsm_mux *gsm_alloc_mux(void) 2191 { 2192 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL); 2193 if (gsm == NULL) 2194 return NULL; 2195 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL); 2196 if (gsm->buf == NULL) { 2197 kfree(gsm); 2198 return NULL; 2199 } 2200 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL); 2201 if (gsm->txframe == NULL) { 2202 kfree(gsm->buf); 2203 kfree(gsm); 2204 return NULL; 2205 } 2206 spin_lock_init(&gsm->lock); 2207 mutex_init(&gsm->mutex); 2208 kref_init(&gsm->ref); 2209 INIT_LIST_HEAD(&gsm->tx_list); 2210 2211 gsm->t1 = T1; 2212 gsm->t2 = T2; 2213 gsm->n2 = N2; 2214 gsm->ftype = UIH; 2215 gsm->adaption = 1; 2216 gsm->encoding = 1; 2217 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */ 2218 gsm->mtu = 64; 2219 gsm->dead = 1; /* Avoid early tty opens */ 2220 2221 return gsm; 2222 } 2223 2224 static void gsm_copy_config_values(struct gsm_mux *gsm, 2225 struct gsm_config *c) 2226 { 2227 memset(c, 0, sizeof(*c)); 2228 c->adaption = gsm->adaption; 2229 c->encapsulation = gsm->encoding; 2230 c->initiator = gsm->initiator; 2231 c->t1 = gsm->t1; 2232 c->t2 = gsm->t2; 2233 c->t3 = 0; /* Not supported */ 2234 c->n2 = gsm->n2; 2235 if (gsm->ftype == UIH) 2236 c->i = 1; 2237 else 2238 c->i = 2; 2239 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i); 2240 c->mru = gsm->mru; 2241 c->mtu = gsm->mtu; 2242 c->k = 0; 2243 } 2244 2245 static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c) 2246 { 2247 int need_close = 0; 2248 int need_restart = 0; 2249 2250 /* Stuff we don't support yet - UI or I frame transport, windowing */ 2251 if ((c->adaption != 1 && c->adaption != 2) || c->k) 2252 return -EOPNOTSUPP; 2253 /* Check the MRU/MTU range looks sane */ 2254 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8) 2255 return -EINVAL; 2256 if (c->n2 < 3) 2257 return -EINVAL; 2258 if (c->encapsulation > 1) /* Basic, advanced, no I */ 2259 return -EINVAL; 2260 if (c->initiator > 1) 2261 return -EINVAL; 2262 if (c->i == 0 || c->i > 2) /* UIH and UI only */ 2263 return -EINVAL; 2264 /* 2265 * See what is needed for reconfiguration 2266 */ 2267 2268 /* Timing fields */ 2269 if (c->t1 != 0 && c->t1 != gsm->t1) 2270 need_restart = 1; 2271 if (c->t2 != 0 && c->t2 != gsm->t2) 2272 need_restart = 1; 2273 if (c->encapsulation != gsm->encoding) 2274 need_restart = 1; 2275 if (c->adaption != gsm->adaption) 2276 need_restart = 1; 2277 /* Requires care */ 2278 if (c->initiator != gsm->initiator) 2279 need_close = 1; 2280 if (c->mru != gsm->mru) 2281 need_restart = 1; 2282 if (c->mtu != gsm->mtu) 2283 need_restart = 1; 2284 2285 /* 2286 * Close down what is needed, restart and initiate the new 2287 * configuration 2288 */ 2289 2290 if (need_close || need_restart) { 2291 int ret; 2292 2293 ret = gsm_disconnect(gsm); 2294 2295 if (ret) 2296 return ret; 2297 } 2298 if (need_restart) 2299 gsm_cleanup_mux(gsm); 2300 2301 gsm->initiator = c->initiator; 2302 gsm->mru = c->mru; 2303 gsm->mtu = c->mtu; 2304 gsm->encoding = c->encapsulation; 2305 gsm->adaption = c->adaption; 2306 gsm->n2 = c->n2; 2307 2308 if (c->i == 1) 2309 gsm->ftype = UIH; 2310 else if (c->i == 2) 2311 gsm->ftype = UI; 2312 2313 if (c->t1) 2314 gsm->t1 = c->t1; 2315 if (c->t2) 2316 gsm->t2 = c->t2; 2317 2318 /* 2319 * FIXME: We need to separate activation/deactivation from adding 2320 * and removing from the mux array 2321 */ 2322 if (need_restart) 2323 gsm_activate_mux(gsm); 2324 if (gsm->initiator && need_close) 2325 gsm_dlci_begin_open(gsm->dlci[0]); 2326 return 0; 2327 } 2328 2329 /** 2330 * gsmld_output - write to link 2331 * @gsm: our mux 2332 * @data: bytes to output 2333 * @len: size 2334 * 2335 * Write a block of data from the GSM mux to the data channel. This 2336 * will eventually be serialized from above but at the moment isn't. 2337 */ 2338 2339 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len) 2340 { 2341 if (tty_write_room(gsm->tty) < len) { 2342 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags); 2343 return -ENOSPC; 2344 } 2345 if (debug & 4) 2346 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET, 2347 data, len); 2348 gsm->tty->ops->write(gsm->tty, data, len); 2349 return len; 2350 } 2351 2352 /** 2353 * gsmld_attach_gsm - mode set up 2354 * @tty: our tty structure 2355 * @gsm: our mux 2356 * 2357 * Set up the MUX for basic mode and commence connecting to the 2358 * modem. Currently called from the line discipline set up but 2359 * will need moving to an ioctl path. 2360 */ 2361 2362 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 2363 { 2364 unsigned int base; 2365 int ret, i; 2366 2367 gsm->tty = tty_kref_get(tty); 2368 gsm->output = gsmld_output; 2369 ret = gsm_activate_mux(gsm); 2370 if (ret != 0) 2371 tty_kref_put(gsm->tty); 2372 else { 2373 /* Don't register device 0 - this is the control channel and not 2374 a usable tty interface */ 2375 base = mux_num_to_base(gsm); /* Base for this MUX */ 2376 for (i = 1; i < NUM_DLCI; i++) 2377 tty_register_device(gsm_tty_driver, base + i, NULL); 2378 } 2379 return ret; 2380 } 2381 2382 2383 /** 2384 * gsmld_detach_gsm - stop doing 0710 mux 2385 * @tty: tty attached to the mux 2386 * @gsm: mux 2387 * 2388 * Shutdown and then clean up the resources used by the line discipline 2389 */ 2390 2391 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 2392 { 2393 unsigned int base = mux_num_to_base(gsm); /* Base for this MUX */ 2394 int i; 2395 2396 WARN_ON(tty != gsm->tty); 2397 for (i = 1; i < NUM_DLCI; i++) 2398 tty_unregister_device(gsm_tty_driver, base + i); 2399 gsm_cleanup_mux(gsm); 2400 tty_kref_put(gsm->tty); 2401 gsm->tty = NULL; 2402 } 2403 2404 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, 2405 char *fp, int count) 2406 { 2407 struct gsm_mux *gsm = tty->disc_data; 2408 const unsigned char *dp; 2409 char *f; 2410 int i; 2411 char flags = TTY_NORMAL; 2412 2413 if (debug & 4) 2414 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET, 2415 cp, count); 2416 2417 for (i = count, dp = cp, f = fp; i; i--, dp++) { 2418 if (f) 2419 flags = *f++; 2420 switch (flags) { 2421 case TTY_NORMAL: 2422 gsm->receive(gsm, *dp); 2423 break; 2424 case TTY_OVERRUN: 2425 case TTY_BREAK: 2426 case TTY_PARITY: 2427 case TTY_FRAME: 2428 gsm->error(gsm, *dp, flags); 2429 break; 2430 default: 2431 WARN_ONCE(1, "%s: unknown flag %d\n", 2432 tty_name(tty), flags); 2433 break; 2434 } 2435 } 2436 /* FASYNC if needed ? */ 2437 /* If clogged call tty_throttle(tty); */ 2438 } 2439 2440 /** 2441 * gsmld_flush_buffer - clean input queue 2442 * @tty: terminal device 2443 * 2444 * Flush the input buffer. Called when the line discipline is 2445 * being closed, when the tty layer wants the buffer flushed (eg 2446 * at hangup). 2447 */ 2448 2449 static void gsmld_flush_buffer(struct tty_struct *tty) 2450 { 2451 } 2452 2453 /** 2454 * gsmld_close - close the ldisc for this tty 2455 * @tty: device 2456 * 2457 * Called from the terminal layer when this line discipline is 2458 * being shut down, either because of a close or becsuse of a 2459 * discipline change. The function will not be called while other 2460 * ldisc methods are in progress. 2461 */ 2462 2463 static void gsmld_close(struct tty_struct *tty) 2464 { 2465 struct gsm_mux *gsm = tty->disc_data; 2466 2467 gsmld_detach_gsm(tty, gsm); 2468 2469 gsmld_flush_buffer(tty); 2470 /* Do other clean up here */ 2471 mux_put(gsm); 2472 } 2473 2474 /** 2475 * gsmld_open - open an ldisc 2476 * @tty: terminal to open 2477 * 2478 * Called when this line discipline is being attached to the 2479 * terminal device. Can sleep. Called serialized so that no 2480 * other events will occur in parallel. No further open will occur 2481 * until a close. 2482 */ 2483 2484 static int gsmld_open(struct tty_struct *tty) 2485 { 2486 struct gsm_mux *gsm; 2487 int ret; 2488 2489 if (tty->ops->write == NULL) 2490 return -EINVAL; 2491 2492 /* Attach our ldisc data */ 2493 gsm = gsm_alloc_mux(); 2494 if (gsm == NULL) 2495 return -ENOMEM; 2496 2497 tty->disc_data = gsm; 2498 tty->receive_room = 65536; 2499 2500 /* Attach the initial passive connection */ 2501 gsm->encoding = 1; 2502 2503 ret = gsmld_attach_gsm(tty, gsm); 2504 if (ret != 0) { 2505 gsm_cleanup_mux(gsm); 2506 mux_put(gsm); 2507 } 2508 return ret; 2509 } 2510 2511 /** 2512 * gsmld_write_wakeup - asynchronous I/O notifier 2513 * @tty: tty device 2514 * 2515 * Required for the ptys, serial driver etc. since processes 2516 * that attach themselves to the master and rely on ASYNC 2517 * IO must be woken up 2518 */ 2519 2520 static void gsmld_write_wakeup(struct tty_struct *tty) 2521 { 2522 struct gsm_mux *gsm = tty->disc_data; 2523 unsigned long flags; 2524 2525 /* Queue poll */ 2526 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 2527 spin_lock_irqsave(&gsm->tx_lock, flags); 2528 gsm_data_kick(gsm); 2529 if (gsm->tx_bytes < TX_THRESH_LO) { 2530 gsm_dlci_data_sweep(gsm); 2531 } 2532 spin_unlock_irqrestore(&gsm->tx_lock, flags); 2533 } 2534 2535 /** 2536 * gsmld_read - read function for tty 2537 * @tty: tty device 2538 * @file: file object 2539 * @buf: userspace buffer pointer 2540 * @nr: size of I/O 2541 * 2542 * Perform reads for the line discipline. We are guaranteed that the 2543 * line discipline will not be closed under us but we may get multiple 2544 * parallel readers and must handle this ourselves. We may also get 2545 * a hangup. Always called in user context, may sleep. 2546 * 2547 * This code must be sure never to sleep through a hangup. 2548 */ 2549 2550 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, 2551 unsigned char __user *buf, size_t nr) 2552 { 2553 return -EOPNOTSUPP; 2554 } 2555 2556 /** 2557 * gsmld_write - write function for tty 2558 * @tty: tty device 2559 * @file: file object 2560 * @buf: userspace buffer pointer 2561 * @nr: size of I/O 2562 * 2563 * Called when the owner of the device wants to send a frame 2564 * itself (or some other control data). The data is transferred 2565 * as-is and must be properly framed and checksummed as appropriate 2566 * by userspace. Frames are either sent whole or not at all as this 2567 * avoids pain user side. 2568 */ 2569 2570 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file, 2571 const unsigned char *buf, size_t nr) 2572 { 2573 int space = tty_write_room(tty); 2574 if (space >= nr) 2575 return tty->ops->write(tty, buf, nr); 2576 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 2577 return -ENOBUFS; 2578 } 2579 2580 /** 2581 * gsmld_poll - poll method for N_GSM0710 2582 * @tty: terminal device 2583 * @file: file accessing it 2584 * @wait: poll table 2585 * 2586 * Called when the line discipline is asked to poll() for data or 2587 * for special events. This code is not serialized with respect to 2588 * other events save open/close. 2589 * 2590 * This code must be sure never to sleep through a hangup. 2591 * Called without the kernel lock held - fine 2592 */ 2593 2594 static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file, 2595 poll_table *wait) 2596 { 2597 __poll_t mask = 0; 2598 struct gsm_mux *gsm = tty->disc_data; 2599 2600 poll_wait(file, &tty->read_wait, wait); 2601 poll_wait(file, &tty->write_wait, wait); 2602 if (tty_hung_up_p(file)) 2603 mask |= EPOLLHUP; 2604 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0) 2605 mask |= EPOLLOUT | EPOLLWRNORM; 2606 if (gsm->dead) 2607 mask |= EPOLLHUP; 2608 return mask; 2609 } 2610 2611 static int gsmld_ioctl(struct tty_struct *tty, struct file *file, 2612 unsigned int cmd, unsigned long arg) 2613 { 2614 struct gsm_config c; 2615 struct gsm_mux *gsm = tty->disc_data; 2616 unsigned int base; 2617 2618 switch (cmd) { 2619 case GSMIOC_GETCONF: 2620 gsm_copy_config_values(gsm, &c); 2621 if (copy_to_user((void *)arg, &c, sizeof(c))) 2622 return -EFAULT; 2623 return 0; 2624 case GSMIOC_SETCONF: 2625 if (copy_from_user(&c, (void *)arg, sizeof(c))) 2626 return -EFAULT; 2627 return gsm_config(gsm, &c); 2628 case GSMIOC_GETFIRST: 2629 base = mux_num_to_base(gsm); 2630 return put_user(base + 1, (__u32 __user *)arg); 2631 default: 2632 return n_tty_ioctl_helper(tty, file, cmd, arg); 2633 } 2634 } 2635 2636 /* 2637 * Network interface 2638 * 2639 */ 2640 2641 static int gsm_mux_net_open(struct net_device *net) 2642 { 2643 pr_debug("%s called\n", __func__); 2644 netif_start_queue(net); 2645 return 0; 2646 } 2647 2648 static int gsm_mux_net_close(struct net_device *net) 2649 { 2650 netif_stop_queue(net); 2651 return 0; 2652 } 2653 2654 static void dlci_net_free(struct gsm_dlci *dlci) 2655 { 2656 if (!dlci->net) { 2657 WARN_ON(1); 2658 return; 2659 } 2660 dlci->adaption = dlci->prev_adaption; 2661 dlci->data = dlci->prev_data; 2662 free_netdev(dlci->net); 2663 dlci->net = NULL; 2664 } 2665 static void net_free(struct kref *ref) 2666 { 2667 struct gsm_mux_net *mux_net; 2668 struct gsm_dlci *dlci; 2669 2670 mux_net = container_of(ref, struct gsm_mux_net, ref); 2671 dlci = mux_net->dlci; 2672 2673 if (dlci->net) { 2674 unregister_netdev(dlci->net); 2675 dlci_net_free(dlci); 2676 } 2677 } 2678 2679 static inline void muxnet_get(struct gsm_mux_net *mux_net) 2680 { 2681 kref_get(&mux_net->ref); 2682 } 2683 2684 static inline void muxnet_put(struct gsm_mux_net *mux_net) 2685 { 2686 kref_put(&mux_net->ref, net_free); 2687 } 2688 2689 static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb, 2690 struct net_device *net) 2691 { 2692 struct gsm_mux_net *mux_net = netdev_priv(net); 2693 struct gsm_dlci *dlci = mux_net->dlci; 2694 muxnet_get(mux_net); 2695 2696 skb_queue_head(&dlci->skb_list, skb); 2697 net->stats.tx_packets++; 2698 net->stats.tx_bytes += skb->len; 2699 gsm_dlci_data_kick(dlci); 2700 /* And tell the kernel when the last transmit started. */ 2701 netif_trans_update(net); 2702 muxnet_put(mux_net); 2703 return NETDEV_TX_OK; 2704 } 2705 2706 /* called when a packet did not ack after watchdogtimeout */ 2707 static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue) 2708 { 2709 /* Tell syslog we are hosed. */ 2710 dev_dbg(&net->dev, "Tx timed out.\n"); 2711 2712 /* Update statistics */ 2713 net->stats.tx_errors++; 2714 } 2715 2716 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci, 2717 const unsigned char *in_buf, int size) 2718 { 2719 struct net_device *net = dlci->net; 2720 struct sk_buff *skb; 2721 struct gsm_mux_net *mux_net = netdev_priv(net); 2722 muxnet_get(mux_net); 2723 2724 /* Allocate an sk_buff */ 2725 skb = dev_alloc_skb(size + NET_IP_ALIGN); 2726 if (!skb) { 2727 /* We got no receive buffer. */ 2728 net->stats.rx_dropped++; 2729 muxnet_put(mux_net); 2730 return; 2731 } 2732 skb_reserve(skb, NET_IP_ALIGN); 2733 skb_put_data(skb, in_buf, size); 2734 2735 skb->dev = net; 2736 skb->protocol = htons(ETH_P_IP); 2737 2738 /* Ship it off to the kernel */ 2739 netif_rx(skb); 2740 2741 /* update out statistics */ 2742 net->stats.rx_packets++; 2743 net->stats.rx_bytes += size; 2744 muxnet_put(mux_net); 2745 return; 2746 } 2747 2748 static void gsm_mux_net_init(struct net_device *net) 2749 { 2750 static const struct net_device_ops gsm_netdev_ops = { 2751 .ndo_open = gsm_mux_net_open, 2752 .ndo_stop = gsm_mux_net_close, 2753 .ndo_start_xmit = gsm_mux_net_start_xmit, 2754 .ndo_tx_timeout = gsm_mux_net_tx_timeout, 2755 }; 2756 2757 net->netdev_ops = &gsm_netdev_ops; 2758 2759 /* fill in the other fields */ 2760 net->watchdog_timeo = GSM_NET_TX_TIMEOUT; 2761 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 2762 net->type = ARPHRD_NONE; 2763 net->tx_queue_len = 10; 2764 } 2765 2766 2767 /* caller holds the dlci mutex */ 2768 static void gsm_destroy_network(struct gsm_dlci *dlci) 2769 { 2770 struct gsm_mux_net *mux_net; 2771 2772 pr_debug("destroy network interface"); 2773 if (!dlci->net) 2774 return; 2775 mux_net = netdev_priv(dlci->net); 2776 muxnet_put(mux_net); 2777 } 2778 2779 2780 /* caller holds the dlci mutex */ 2781 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc) 2782 { 2783 char *netname; 2784 int retval = 0; 2785 struct net_device *net; 2786 struct gsm_mux_net *mux_net; 2787 2788 if (!capable(CAP_NET_ADMIN)) 2789 return -EPERM; 2790 2791 /* Already in a non tty mode */ 2792 if (dlci->adaption > 2) 2793 return -EBUSY; 2794 2795 if (nc->protocol != htons(ETH_P_IP)) 2796 return -EPROTONOSUPPORT; 2797 2798 if (nc->adaption != 3 && nc->adaption != 4) 2799 return -EPROTONOSUPPORT; 2800 2801 pr_debug("create network interface"); 2802 2803 netname = "gsm%d"; 2804 if (nc->if_name[0] != '\0') 2805 netname = nc->if_name; 2806 net = alloc_netdev(sizeof(struct gsm_mux_net), netname, 2807 NET_NAME_UNKNOWN, gsm_mux_net_init); 2808 if (!net) { 2809 pr_err("alloc_netdev failed"); 2810 return -ENOMEM; 2811 } 2812 net->mtu = dlci->gsm->mtu; 2813 net->min_mtu = 8; 2814 net->max_mtu = dlci->gsm->mtu; 2815 mux_net = netdev_priv(net); 2816 mux_net->dlci = dlci; 2817 kref_init(&mux_net->ref); 2818 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */ 2819 2820 /* reconfigure dlci for network */ 2821 dlci->prev_adaption = dlci->adaption; 2822 dlci->prev_data = dlci->data; 2823 dlci->adaption = nc->adaption; 2824 dlci->data = gsm_mux_rx_netchar; 2825 dlci->net = net; 2826 2827 pr_debug("register netdev"); 2828 retval = register_netdev(net); 2829 if (retval) { 2830 pr_err("network register fail %d\n", retval); 2831 dlci_net_free(dlci); 2832 return retval; 2833 } 2834 return net->ifindex; /* return network index */ 2835 } 2836 2837 /* Line discipline for real tty */ 2838 static struct tty_ldisc_ops tty_ldisc_packet = { 2839 .owner = THIS_MODULE, 2840 .magic = TTY_LDISC_MAGIC, 2841 .name = "n_gsm", 2842 .open = gsmld_open, 2843 .close = gsmld_close, 2844 .flush_buffer = gsmld_flush_buffer, 2845 .read = gsmld_read, 2846 .write = gsmld_write, 2847 .ioctl = gsmld_ioctl, 2848 .poll = gsmld_poll, 2849 .receive_buf = gsmld_receive_buf, 2850 .write_wakeup = gsmld_write_wakeup 2851 }; 2852 2853 /* 2854 * Virtual tty side 2855 */ 2856 2857 #define TX_SIZE 512 2858 2859 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) 2860 { 2861 u8 modembits[5]; 2862 struct gsm_control *ctrl; 2863 int len = 2; 2864 2865 if (brk) 2866 len++; 2867 2868 modembits[0] = len << 1 | EA; /* Data bytes */ 2869 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */ 2870 modembits[2] = gsm_encode_modem(dlci) << 1 | EA; 2871 if (brk) 2872 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */ 2873 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1); 2874 if (ctrl == NULL) 2875 return -ENOMEM; 2876 return gsm_control_wait(dlci->gsm, ctrl); 2877 } 2878 2879 static int gsm_carrier_raised(struct tty_port *port) 2880 { 2881 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2882 struct gsm_mux *gsm = dlci->gsm; 2883 2884 /* Not yet open so no carrier info */ 2885 if (dlci->state != DLCI_OPEN) 2886 return 0; 2887 if (debug & 2) 2888 return 1; 2889 2890 /* 2891 * Basic mode with control channel in ADM mode may not respond 2892 * to CMD_MSC at all and modem_rx is empty. 2893 */ 2894 if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM && 2895 !dlci->modem_rx) 2896 return 1; 2897 2898 return dlci->modem_rx & TIOCM_CD; 2899 } 2900 2901 static void gsm_dtr_rts(struct tty_port *port, int onoff) 2902 { 2903 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2904 unsigned int modem_tx = dlci->modem_tx; 2905 if (onoff) 2906 modem_tx |= TIOCM_DTR | TIOCM_RTS; 2907 else 2908 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); 2909 if (modem_tx != dlci->modem_tx) { 2910 dlci->modem_tx = modem_tx; 2911 gsmtty_modem_update(dlci, 0); 2912 } 2913 } 2914 2915 static const struct tty_port_operations gsm_port_ops = { 2916 .carrier_raised = gsm_carrier_raised, 2917 .dtr_rts = gsm_dtr_rts, 2918 .destruct = gsm_dlci_free, 2919 }; 2920 2921 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty) 2922 { 2923 struct gsm_mux *gsm; 2924 struct gsm_dlci *dlci; 2925 unsigned int line = tty->index; 2926 unsigned int mux = mux_line_to_num(line); 2927 bool alloc = false; 2928 int ret; 2929 2930 line = line & 0x3F; 2931 2932 if (mux >= MAX_MUX) 2933 return -ENXIO; 2934 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */ 2935 if (gsm_mux[mux] == NULL) 2936 return -EUNATCH; 2937 if (line == 0 || line > 61) /* 62/63 reserved */ 2938 return -ECHRNG; 2939 gsm = gsm_mux[mux]; 2940 if (gsm->dead) 2941 return -EL2HLT; 2942 /* If DLCI 0 is not yet fully open return an error. 2943 This is ok from a locking 2944 perspective as we don't have to worry about this 2945 if DLCI0 is lost */ 2946 mutex_lock(&gsm->mutex); 2947 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) { 2948 mutex_unlock(&gsm->mutex); 2949 return -EL2NSYNC; 2950 } 2951 dlci = gsm->dlci[line]; 2952 if (dlci == NULL) { 2953 alloc = true; 2954 dlci = gsm_dlci_alloc(gsm, line); 2955 } 2956 if (dlci == NULL) { 2957 mutex_unlock(&gsm->mutex); 2958 return -ENOMEM; 2959 } 2960 ret = tty_port_install(&dlci->port, driver, tty); 2961 if (ret) { 2962 if (alloc) 2963 dlci_put(dlci); 2964 mutex_unlock(&gsm->mutex); 2965 return ret; 2966 } 2967 2968 dlci_get(dlci); 2969 dlci_get(gsm->dlci[0]); 2970 mux_get(gsm); 2971 tty->driver_data = dlci; 2972 mutex_unlock(&gsm->mutex); 2973 2974 return 0; 2975 } 2976 2977 static int gsmtty_open(struct tty_struct *tty, struct file *filp) 2978 { 2979 struct gsm_dlci *dlci = tty->driver_data; 2980 struct tty_port *port = &dlci->port; 2981 2982 port->count++; 2983 tty_port_tty_set(port, tty); 2984 2985 dlci->modem_rx = 0; 2986 /* We could in theory open and close before we wait - eg if we get 2987 a DM straight back. This is ok as that will have caused a hangup */ 2988 tty_port_set_initialized(port, 1); 2989 /* Start sending off SABM messages */ 2990 gsm_dlci_begin_open(dlci); 2991 /* And wait for virtual carrier */ 2992 return tty_port_block_til_ready(port, tty, filp); 2993 } 2994 2995 static void gsmtty_close(struct tty_struct *tty, struct file *filp) 2996 { 2997 struct gsm_dlci *dlci = tty->driver_data; 2998 2999 if (dlci == NULL) 3000 return; 3001 if (dlci->state == DLCI_CLOSED) 3002 return; 3003 mutex_lock(&dlci->mutex); 3004 gsm_destroy_network(dlci); 3005 mutex_unlock(&dlci->mutex); 3006 if (tty_port_close_start(&dlci->port, tty, filp) == 0) 3007 return; 3008 gsm_dlci_begin_close(dlci); 3009 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty)) 3010 tty_port_lower_dtr_rts(&dlci->port); 3011 tty_port_close_end(&dlci->port, tty); 3012 tty_port_tty_set(&dlci->port, NULL); 3013 return; 3014 } 3015 3016 static void gsmtty_hangup(struct tty_struct *tty) 3017 { 3018 struct gsm_dlci *dlci = tty->driver_data; 3019 if (dlci->state == DLCI_CLOSED) 3020 return; 3021 tty_port_hangup(&dlci->port); 3022 gsm_dlci_begin_close(dlci); 3023 } 3024 3025 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf, 3026 int len) 3027 { 3028 int sent; 3029 struct gsm_dlci *dlci = tty->driver_data; 3030 if (dlci->state == DLCI_CLOSED) 3031 return -EINVAL; 3032 /* Stuff the bytes into the fifo queue */ 3033 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock); 3034 /* Need to kick the channel */ 3035 gsm_dlci_data_kick(dlci); 3036 return sent; 3037 } 3038 3039 static int gsmtty_write_room(struct tty_struct *tty) 3040 { 3041 struct gsm_dlci *dlci = tty->driver_data; 3042 if (dlci->state == DLCI_CLOSED) 3043 return -EINVAL; 3044 return TX_SIZE - kfifo_len(dlci->fifo); 3045 } 3046 3047 static int gsmtty_chars_in_buffer(struct tty_struct *tty) 3048 { 3049 struct gsm_dlci *dlci = tty->driver_data; 3050 if (dlci->state == DLCI_CLOSED) 3051 return -EINVAL; 3052 return kfifo_len(dlci->fifo); 3053 } 3054 3055 static void gsmtty_flush_buffer(struct tty_struct *tty) 3056 { 3057 struct gsm_dlci *dlci = tty->driver_data; 3058 if (dlci->state == DLCI_CLOSED) 3059 return; 3060 /* Caution needed: If we implement reliable transport classes 3061 then the data being transmitted can't simply be junked once 3062 it has first hit the stack. Until then we can just blow it 3063 away */ 3064 kfifo_reset(dlci->fifo); 3065 /* Need to unhook this DLCI from the transmit queue logic */ 3066 } 3067 3068 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout) 3069 { 3070 /* The FIFO handles the queue so the kernel will do the right 3071 thing waiting on chars_in_buffer before calling us. No work 3072 to do here */ 3073 } 3074 3075 static int gsmtty_tiocmget(struct tty_struct *tty) 3076 { 3077 struct gsm_dlci *dlci = tty->driver_data; 3078 if (dlci->state == DLCI_CLOSED) 3079 return -EINVAL; 3080 return dlci->modem_rx; 3081 } 3082 3083 static int gsmtty_tiocmset(struct tty_struct *tty, 3084 unsigned int set, unsigned int clear) 3085 { 3086 struct gsm_dlci *dlci = tty->driver_data; 3087 unsigned int modem_tx = dlci->modem_tx; 3088 3089 if (dlci->state == DLCI_CLOSED) 3090 return -EINVAL; 3091 modem_tx &= ~clear; 3092 modem_tx |= set; 3093 3094 if (modem_tx != dlci->modem_tx) { 3095 dlci->modem_tx = modem_tx; 3096 return gsmtty_modem_update(dlci, 0); 3097 } 3098 return 0; 3099 } 3100 3101 3102 static int gsmtty_ioctl(struct tty_struct *tty, 3103 unsigned int cmd, unsigned long arg) 3104 { 3105 struct gsm_dlci *dlci = tty->driver_data; 3106 struct gsm_netconfig nc; 3107 int index; 3108 3109 if (dlci->state == DLCI_CLOSED) 3110 return -EINVAL; 3111 switch (cmd) { 3112 case GSMIOC_ENABLE_NET: 3113 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc))) 3114 return -EFAULT; 3115 nc.if_name[IFNAMSIZ-1] = '\0'; 3116 /* return net interface index or error code */ 3117 mutex_lock(&dlci->mutex); 3118 index = gsm_create_network(dlci, &nc); 3119 mutex_unlock(&dlci->mutex); 3120 if (copy_to_user((void __user *)arg, &nc, sizeof(nc))) 3121 return -EFAULT; 3122 return index; 3123 case GSMIOC_DISABLE_NET: 3124 if (!capable(CAP_NET_ADMIN)) 3125 return -EPERM; 3126 mutex_lock(&dlci->mutex); 3127 gsm_destroy_network(dlci); 3128 mutex_unlock(&dlci->mutex); 3129 return 0; 3130 default: 3131 return -ENOIOCTLCMD; 3132 } 3133 } 3134 3135 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old) 3136 { 3137 struct gsm_dlci *dlci = tty->driver_data; 3138 if (dlci->state == DLCI_CLOSED) 3139 return; 3140 /* For the moment its fixed. In actual fact the speed information 3141 for the virtual channel can be propogated in both directions by 3142 the RPN control message. This however rapidly gets nasty as we 3143 then have to remap modem signals each way according to whether 3144 our virtual cable is null modem etc .. */ 3145 tty_termios_copy_hw(&tty->termios, old); 3146 } 3147 3148 static void gsmtty_throttle(struct tty_struct *tty) 3149 { 3150 struct gsm_dlci *dlci = tty->driver_data; 3151 if (dlci->state == DLCI_CLOSED) 3152 return; 3153 if (C_CRTSCTS(tty)) 3154 dlci->modem_tx &= ~TIOCM_DTR; 3155 dlci->throttled = 1; 3156 /* Send an MSC with DTR cleared */ 3157 gsmtty_modem_update(dlci, 0); 3158 } 3159 3160 static void gsmtty_unthrottle(struct tty_struct *tty) 3161 { 3162 struct gsm_dlci *dlci = tty->driver_data; 3163 if (dlci->state == DLCI_CLOSED) 3164 return; 3165 if (C_CRTSCTS(tty)) 3166 dlci->modem_tx |= TIOCM_DTR; 3167 dlci->throttled = 0; 3168 /* Send an MSC with DTR set */ 3169 gsmtty_modem_update(dlci, 0); 3170 } 3171 3172 static int gsmtty_break_ctl(struct tty_struct *tty, int state) 3173 { 3174 struct gsm_dlci *dlci = tty->driver_data; 3175 int encode = 0; /* Off */ 3176 if (dlci->state == DLCI_CLOSED) 3177 return -EINVAL; 3178 3179 if (state == -1) /* "On indefinitely" - we can't encode this 3180 properly */ 3181 encode = 0x0F; 3182 else if (state > 0) { 3183 encode = state / 200; /* mS to encoding */ 3184 if (encode > 0x0F) 3185 encode = 0x0F; /* Best effort */ 3186 } 3187 return gsmtty_modem_update(dlci, encode); 3188 } 3189 3190 static void gsmtty_cleanup(struct tty_struct *tty) 3191 { 3192 struct gsm_dlci *dlci = tty->driver_data; 3193 struct gsm_mux *gsm = dlci->gsm; 3194 3195 dlci_put(dlci); 3196 dlci_put(gsm->dlci[0]); 3197 mux_put(gsm); 3198 } 3199 3200 /* Virtual ttys for the demux */ 3201 static const struct tty_operations gsmtty_ops = { 3202 .install = gsmtty_install, 3203 .open = gsmtty_open, 3204 .close = gsmtty_close, 3205 .write = gsmtty_write, 3206 .write_room = gsmtty_write_room, 3207 .chars_in_buffer = gsmtty_chars_in_buffer, 3208 .flush_buffer = gsmtty_flush_buffer, 3209 .ioctl = gsmtty_ioctl, 3210 .throttle = gsmtty_throttle, 3211 .unthrottle = gsmtty_unthrottle, 3212 .set_termios = gsmtty_set_termios, 3213 .hangup = gsmtty_hangup, 3214 .wait_until_sent = gsmtty_wait_until_sent, 3215 .tiocmget = gsmtty_tiocmget, 3216 .tiocmset = gsmtty_tiocmset, 3217 .break_ctl = gsmtty_break_ctl, 3218 .cleanup = gsmtty_cleanup, 3219 }; 3220 3221 3222 3223 static int __init gsm_init(void) 3224 { 3225 /* Fill in our line protocol discipline, and register it */ 3226 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet); 3227 if (status != 0) { 3228 pr_err("n_gsm: can't register line discipline (err = %d)\n", 3229 status); 3230 return status; 3231 } 3232 3233 gsm_tty_driver = alloc_tty_driver(256); 3234 if (!gsm_tty_driver) { 3235 tty_unregister_ldisc(N_GSM0710); 3236 pr_err("gsm_init: tty allocation failed.\n"); 3237 return -EINVAL; 3238 } 3239 gsm_tty_driver->driver_name = "gsmtty"; 3240 gsm_tty_driver->name = "gsmtty"; 3241 gsm_tty_driver->major = 0; /* Dynamic */ 3242 gsm_tty_driver->minor_start = 0; 3243 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; 3244 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL; 3245 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV 3246 | TTY_DRIVER_HARDWARE_BREAK; 3247 gsm_tty_driver->init_termios = tty_std_termios; 3248 /* Fixme */ 3249 gsm_tty_driver->init_termios.c_lflag &= ~ECHO; 3250 tty_set_operations(gsm_tty_driver, &gsmtty_ops); 3251 3252 spin_lock_init(&gsm_mux_lock); 3253 3254 if (tty_register_driver(gsm_tty_driver)) { 3255 put_tty_driver(gsm_tty_driver); 3256 tty_unregister_ldisc(N_GSM0710); 3257 pr_err("gsm_init: tty registration failed.\n"); 3258 return -EBUSY; 3259 } 3260 pr_debug("gsm_init: loaded as %d,%d.\n", 3261 gsm_tty_driver->major, gsm_tty_driver->minor_start); 3262 return 0; 3263 } 3264 3265 static void __exit gsm_exit(void) 3266 { 3267 int status = tty_unregister_ldisc(N_GSM0710); 3268 if (status != 0) 3269 pr_err("n_gsm: can't unregister line discipline (err = %d)\n", 3270 status); 3271 tty_unregister_driver(gsm_tty_driver); 3272 put_tty_driver(gsm_tty_driver); 3273 } 3274 3275 module_init(gsm_init); 3276 module_exit(gsm_exit); 3277 3278 3279 MODULE_LICENSE("GPL"); 3280 MODULE_ALIAS_LDISC(N_GSM0710); 3281