1 /* 2 * n_gsm.c GSM 0710 tty multiplexor 3 * Copyright (c) 2009/10 Intel Corporation 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 17 * 18 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE * 19 * 20 * TO DO: 21 * Mostly done: ioctls for setting modes/timing 22 * Partly done: hooks so you can pull off frames to non tty devs 23 * Restart DLCI 0 when it closes ? 24 * Improve the tx engine 25 * Resolve tx side locking by adding a queue_head and routing 26 * all control traffic via it 27 * General tidy/document 28 * Review the locking/move to refcounts more (mux now moved to an 29 * alloc/free model ready) 30 * Use newest tty open/close port helpers and install hooks 31 * What to do about power functions ? 32 * Termios setting and negotiation 33 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets 34 * 35 */ 36 37 #include <linux/types.h> 38 #include <linux/major.h> 39 #include <linux/errno.h> 40 #include <linux/signal.h> 41 #include <linux/fcntl.h> 42 #include <linux/sched.h> 43 #include <linux/interrupt.h> 44 #include <linux/tty.h> 45 #include <linux/ctype.h> 46 #include <linux/mm.h> 47 #include <linux/string.h> 48 #include <linux/slab.h> 49 #include <linux/poll.h> 50 #include <linux/bitops.h> 51 #include <linux/file.h> 52 #include <linux/uaccess.h> 53 #include <linux/module.h> 54 #include <linux/timer.h> 55 #include <linux/tty_flip.h> 56 #include <linux/tty_driver.h> 57 #include <linux/serial.h> 58 #include <linux/kfifo.h> 59 #include <linux/skbuff.h> 60 #include <net/arp.h> 61 #include <linux/ip.h> 62 #include <linux/netdevice.h> 63 #include <linux/etherdevice.h> 64 #include <linux/gsmmux.h> 65 66 static int debug; 67 module_param(debug, int, 0600); 68 69 /* Defaults: these are from the specification */ 70 71 #define T1 10 /* 100mS */ 72 #define T2 34 /* 333mS */ 73 #define N2 3 /* Retry 3 times */ 74 75 /* Use long timers for testing at low speed with debug on */ 76 #ifdef DEBUG_TIMING 77 #define T1 100 78 #define T2 200 79 #endif 80 81 /* 82 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte 83 * limits so this is plenty 84 */ 85 #define MAX_MRU 1500 86 #define MAX_MTU 1500 87 #define GSM_NET_TX_TIMEOUT (HZ*10) 88 89 /** 90 * struct gsm_mux_net - network interface 91 * @struct gsm_dlci* dlci 92 * @struct net_device_stats stats; 93 * 94 * Created when net interface is initialized. 95 **/ 96 struct gsm_mux_net { 97 struct kref ref; 98 struct gsm_dlci *dlci; 99 struct net_device_stats stats; 100 }; 101 102 #define STATS(net) (((struct gsm_mux_net *)netdev_priv(net))->stats) 103 104 /* 105 * Each block of data we have queued to go out is in the form of 106 * a gsm_msg which holds everything we need in a link layer independent 107 * format 108 */ 109 110 struct gsm_msg { 111 struct list_head list; 112 u8 addr; /* DLCI address + flags */ 113 u8 ctrl; /* Control byte + flags */ 114 unsigned int len; /* Length of data block (can be zero) */ 115 unsigned char *data; /* Points into buffer but not at the start */ 116 unsigned char buffer[0]; 117 }; 118 119 /* 120 * Each active data link has a gsm_dlci structure associated which ties 121 * the link layer to an optional tty (if the tty side is open). To avoid 122 * complexity right now these are only ever freed up when the mux is 123 * shut down. 124 * 125 * At the moment we don't free DLCI objects until the mux is torn down 126 * this avoid object life time issues but might be worth review later. 127 */ 128 129 struct gsm_dlci { 130 struct gsm_mux *gsm; 131 int addr; 132 int state; 133 #define DLCI_CLOSED 0 134 #define DLCI_OPENING 1 /* Sending SABM not seen UA */ 135 #define DLCI_OPEN 2 /* SABM/UA complete */ 136 #define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */ 137 struct mutex mutex; 138 139 /* Link layer */ 140 spinlock_t lock; /* Protects the internal state */ 141 struct timer_list t1; /* Retransmit timer for SABM and UA */ 142 int retries; 143 /* Uplink tty if active */ 144 struct tty_port port; /* The tty bound to this DLCI if there is one */ 145 struct kfifo *fifo; /* Queue fifo for the DLCI */ 146 struct kfifo _fifo; /* For new fifo API porting only */ 147 int adaption; /* Adaption layer in use */ 148 int prev_adaption; 149 u32 modem_rx; /* Our incoming virtual modem lines */ 150 u32 modem_tx; /* Our outgoing modem lines */ 151 int dead; /* Refuse re-open */ 152 /* Flow control */ 153 int throttled; /* Private copy of throttle state */ 154 int constipated; /* Throttle status for outgoing */ 155 /* Packetised I/O */ 156 struct sk_buff *skb; /* Frame being sent */ 157 struct sk_buff_head skb_list; /* Queued frames */ 158 /* Data handling callback */ 159 void (*data)(struct gsm_dlci *dlci, u8 *data, int len); 160 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len); 161 struct net_device *net; /* network interface, if created */ 162 }; 163 164 /* DLCI 0, 62/63 are special or reseved see gsmtty_open */ 165 166 #define NUM_DLCI 64 167 168 /* 169 * DLCI 0 is used to pass control blocks out of band of the data 170 * flow (and with a higher link priority). One command can be outstanding 171 * at a time and we use this structure to manage them. They are created 172 * and destroyed by the user context, and updated by the receive paths 173 * and timers 174 */ 175 176 struct gsm_control { 177 u8 cmd; /* Command we are issuing */ 178 u8 *data; /* Data for the command in case we retransmit */ 179 int len; /* Length of block for retransmission */ 180 int done; /* Done flag */ 181 int error; /* Error if any */ 182 }; 183 184 /* 185 * Each GSM mux we have is represented by this structure. If we are 186 * operating as an ldisc then we use this structure as our ldisc 187 * state. We need to sort out lifetimes and locking with respect 188 * to the gsm mux array. For now we don't free DLCI objects that 189 * have been instantiated until the mux itself is terminated. 190 * 191 * To consider further: tty open versus mux shutdown. 192 */ 193 194 struct gsm_mux { 195 struct tty_struct *tty; /* The tty our ldisc is bound to */ 196 spinlock_t lock; 197 unsigned int num; 198 struct kref ref; 199 200 /* Events on the GSM channel */ 201 wait_queue_head_t event; 202 203 /* Bits for GSM mode decoding */ 204 205 /* Framing Layer */ 206 unsigned char *buf; 207 int state; 208 #define GSM_SEARCH 0 209 #define GSM_START 1 210 #define GSM_ADDRESS 2 211 #define GSM_CONTROL 3 212 #define GSM_LEN 4 213 #define GSM_DATA 5 214 #define GSM_FCS 6 215 #define GSM_OVERRUN 7 216 #define GSM_LEN0 8 217 #define GSM_LEN1 9 218 #define GSM_SSOF 10 219 unsigned int len; 220 unsigned int address; 221 unsigned int count; 222 int escape; 223 int encoding; 224 u8 control; 225 u8 fcs; 226 u8 received_fcs; 227 u8 *txframe; /* TX framing buffer */ 228 229 /* Methods for the receiver side */ 230 void (*receive)(struct gsm_mux *gsm, u8 ch); 231 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag); 232 /* And transmit side */ 233 int (*output)(struct gsm_mux *mux, u8 *data, int len); 234 235 /* Link Layer */ 236 unsigned int mru; 237 unsigned int mtu; 238 int initiator; /* Did we initiate connection */ 239 int dead; /* Has the mux been shut down */ 240 struct gsm_dlci *dlci[NUM_DLCI]; 241 int constipated; /* Asked by remote to shut up */ 242 243 spinlock_t tx_lock; 244 unsigned int tx_bytes; /* TX data outstanding */ 245 #define TX_THRESH_HI 8192 246 #define TX_THRESH_LO 2048 247 struct list_head tx_list; /* Pending data packets */ 248 249 /* Control messages */ 250 struct timer_list t2_timer; /* Retransmit timer for commands */ 251 int cretries; /* Command retry counter */ 252 struct gsm_control *pending_cmd;/* Our current pending command */ 253 spinlock_t control_lock; /* Protects the pending command */ 254 255 /* Configuration */ 256 int adaption; /* 1 or 2 supported */ 257 u8 ftype; /* UI or UIH */ 258 int t1, t2; /* Timers in 1/100th of a sec */ 259 int n2; /* Retry count */ 260 261 /* Statistics (not currently exposed) */ 262 unsigned long bad_fcs; 263 unsigned long malformed; 264 unsigned long io_error; 265 unsigned long bad_size; 266 unsigned long unsupported; 267 }; 268 269 270 /* 271 * Mux objects - needed so that we can translate a tty index into the 272 * relevant mux and DLCI. 273 */ 274 275 #define MAX_MUX 4 /* 256 minors */ 276 static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */ 277 static spinlock_t gsm_mux_lock; 278 279 static struct tty_driver *gsm_tty_driver; 280 281 /* 282 * This section of the driver logic implements the GSM encodings 283 * both the basic and the 'advanced'. Reliable transport is not 284 * supported. 285 */ 286 287 #define CR 0x02 288 #define EA 0x01 289 #define PF 0x10 290 291 /* I is special: the rest are ..*/ 292 #define RR 0x01 293 #define UI 0x03 294 #define RNR 0x05 295 #define REJ 0x09 296 #define DM 0x0F 297 #define SABM 0x2F 298 #define DISC 0x43 299 #define UA 0x63 300 #define UIH 0xEF 301 302 /* Channel commands */ 303 #define CMD_NSC 0x09 304 #define CMD_TEST 0x11 305 #define CMD_PSC 0x21 306 #define CMD_RLS 0x29 307 #define CMD_FCOFF 0x31 308 #define CMD_PN 0x41 309 #define CMD_RPN 0x49 310 #define CMD_FCON 0x51 311 #define CMD_CLD 0x61 312 #define CMD_SNC 0x69 313 #define CMD_MSC 0x71 314 315 /* Virtual modem bits */ 316 #define MDM_FC 0x01 317 #define MDM_RTC 0x02 318 #define MDM_RTR 0x04 319 #define MDM_IC 0x20 320 #define MDM_DV 0x40 321 322 #define GSM0_SOF 0xF9 323 #define GSM1_SOF 0x7E 324 #define GSM1_ESCAPE 0x7D 325 #define GSM1_ESCAPE_BITS 0x20 326 #define XON 0x11 327 #define XOFF 0x13 328 329 static const struct tty_port_operations gsm_port_ops; 330 331 /* 332 * CRC table for GSM 0710 333 */ 334 335 static const u8 gsm_fcs8[256] = { 336 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75, 337 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B, 338 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69, 339 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67, 340 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D, 341 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43, 342 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51, 343 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F, 344 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05, 345 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B, 346 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19, 347 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17, 348 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D, 349 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33, 350 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21, 351 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F, 352 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95, 353 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B, 354 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89, 355 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87, 356 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD, 357 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3, 358 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1, 359 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF, 360 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5, 361 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB, 362 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9, 363 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7, 364 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD, 365 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3, 366 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1, 367 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF 368 }; 369 370 #define INIT_FCS 0xFF 371 #define GOOD_FCS 0xCF 372 373 /** 374 * gsm_fcs_add - update FCS 375 * @fcs: Current FCS 376 * @c: Next data 377 * 378 * Update the FCS to include c. Uses the algorithm in the specification 379 * notes. 380 */ 381 382 static inline u8 gsm_fcs_add(u8 fcs, u8 c) 383 { 384 return gsm_fcs8[fcs ^ c]; 385 } 386 387 /** 388 * gsm_fcs_add_block - update FCS for a block 389 * @fcs: Current FCS 390 * @c: buffer of data 391 * @len: length of buffer 392 * 393 * Update the FCS to include c. Uses the algorithm in the specification 394 * notes. 395 */ 396 397 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len) 398 { 399 while (len--) 400 fcs = gsm_fcs8[fcs ^ *c++]; 401 return fcs; 402 } 403 404 /** 405 * gsm_read_ea - read a byte into an EA 406 * @val: variable holding value 407 * c: byte going into the EA 408 * 409 * Processes one byte of an EA. Updates the passed variable 410 * and returns 1 if the EA is now completely read 411 */ 412 413 static int gsm_read_ea(unsigned int *val, u8 c) 414 { 415 /* Add the next 7 bits into the value */ 416 *val <<= 7; 417 *val |= c >> 1; 418 /* Was this the last byte of the EA 1 = yes*/ 419 return c & EA; 420 } 421 422 /** 423 * gsm_encode_modem - encode modem data bits 424 * @dlci: DLCI to encode from 425 * 426 * Returns the correct GSM encoded modem status bits (6 bit field) for 427 * the current status of the DLCI and attached tty object 428 */ 429 430 static u8 gsm_encode_modem(const struct gsm_dlci *dlci) 431 { 432 u8 modembits = 0; 433 /* FC is true flow control not modem bits */ 434 if (dlci->throttled) 435 modembits |= MDM_FC; 436 if (dlci->modem_tx & TIOCM_DTR) 437 modembits |= MDM_RTC; 438 if (dlci->modem_tx & TIOCM_RTS) 439 modembits |= MDM_RTR; 440 if (dlci->modem_tx & TIOCM_RI) 441 modembits |= MDM_IC; 442 if (dlci->modem_tx & TIOCM_CD) 443 modembits |= MDM_DV; 444 return modembits; 445 } 446 447 /** 448 * gsm_print_packet - display a frame for debug 449 * @hdr: header to print before decode 450 * @addr: address EA from the frame 451 * @cr: C/R bit from the frame 452 * @control: control including PF bit 453 * @data: following data bytes 454 * @dlen: length of data 455 * 456 * Displays a packet in human readable format for debugging purposes. The 457 * style is based on amateur radio LAP-B dump display. 458 */ 459 460 static void gsm_print_packet(const char *hdr, int addr, int cr, 461 u8 control, const u8 *data, int dlen) 462 { 463 if (!(debug & 1)) 464 return; 465 466 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]); 467 468 switch (control & ~PF) { 469 case SABM: 470 pr_cont("SABM"); 471 break; 472 case UA: 473 pr_cont("UA"); 474 break; 475 case DISC: 476 pr_cont("DISC"); 477 break; 478 case DM: 479 pr_cont("DM"); 480 break; 481 case UI: 482 pr_cont("UI"); 483 break; 484 case UIH: 485 pr_cont("UIH"); 486 break; 487 default: 488 if (!(control & 0x01)) { 489 pr_cont("I N(S)%d N(R)%d", 490 (control & 0x0E) >> 1, (control & 0xE0) >> 5); 491 } else switch (control & 0x0F) { 492 case RR: 493 pr_cont("RR(%d)", (control & 0xE0) >> 5); 494 break; 495 case RNR: 496 pr_cont("RNR(%d)", (control & 0xE0) >> 5); 497 break; 498 case REJ: 499 pr_cont("REJ(%d)", (control & 0xE0) >> 5); 500 break; 501 default: 502 pr_cont("[%02X]", control); 503 } 504 } 505 506 if (control & PF) 507 pr_cont("(P)"); 508 else 509 pr_cont("(F)"); 510 511 if (dlen) { 512 int ct = 0; 513 while (dlen--) { 514 if (ct % 8 == 0) { 515 pr_cont("\n"); 516 pr_debug(" "); 517 } 518 pr_cont("%02X ", *data++); 519 ct++; 520 } 521 } 522 pr_cont("\n"); 523 } 524 525 526 /* 527 * Link level transmission side 528 */ 529 530 /** 531 * gsm_stuff_packet - bytestuff a packet 532 * @ibuf: input 533 * @obuf: output 534 * @len: length of input 535 * 536 * Expand a buffer by bytestuffing it. The worst case size change 537 * is doubling and the caller is responsible for handing out 538 * suitable sized buffers. 539 */ 540 541 static int gsm_stuff_frame(const u8 *input, u8 *output, int len) 542 { 543 int olen = 0; 544 while (len--) { 545 if (*input == GSM1_SOF || *input == GSM1_ESCAPE 546 || *input == XON || *input == XOFF) { 547 *output++ = GSM1_ESCAPE; 548 *output++ = *input++ ^ GSM1_ESCAPE_BITS; 549 olen++; 550 } else 551 *output++ = *input++; 552 olen++; 553 } 554 return olen; 555 } 556 557 /** 558 * gsm_send - send a control frame 559 * @gsm: our GSM mux 560 * @addr: address for control frame 561 * @cr: command/response bit 562 * @control: control byte including PF bit 563 * 564 * Format up and transmit a control frame. These do not go via the 565 * queueing logic as they should be transmitted ahead of data when 566 * they are needed. 567 * 568 * FIXME: Lock versus data TX path 569 */ 570 571 static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control) 572 { 573 int len; 574 u8 cbuf[10]; 575 u8 ibuf[3]; 576 577 switch (gsm->encoding) { 578 case 0: 579 cbuf[0] = GSM0_SOF; 580 cbuf[1] = (addr << 2) | (cr << 1) | EA; 581 cbuf[2] = control; 582 cbuf[3] = EA; /* Length of data = 0 */ 583 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3); 584 cbuf[5] = GSM0_SOF; 585 len = 6; 586 break; 587 case 1: 588 case 2: 589 /* Control frame + packing (but not frame stuffing) in mode 1 */ 590 ibuf[0] = (addr << 2) | (cr << 1) | EA; 591 ibuf[1] = control; 592 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2); 593 /* Stuffing may double the size worst case */ 594 len = gsm_stuff_frame(ibuf, cbuf + 1, 3); 595 /* Now add the SOF markers */ 596 cbuf[0] = GSM1_SOF; 597 cbuf[len + 1] = GSM1_SOF; 598 /* FIXME: we can omit the lead one in many cases */ 599 len += 2; 600 break; 601 default: 602 WARN_ON(1); 603 return; 604 } 605 gsm->output(gsm, cbuf, len); 606 gsm_print_packet("-->", addr, cr, control, NULL, 0); 607 } 608 609 /** 610 * gsm_response - send a control response 611 * @gsm: our GSM mux 612 * @addr: address for control frame 613 * @control: control byte including PF bit 614 * 615 * Format up and transmit a link level response frame. 616 */ 617 618 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control) 619 { 620 gsm_send(gsm, addr, 0, control); 621 } 622 623 /** 624 * gsm_command - send a control command 625 * @gsm: our GSM mux 626 * @addr: address for control frame 627 * @control: control byte including PF bit 628 * 629 * Format up and transmit a link level command frame. 630 */ 631 632 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control) 633 { 634 gsm_send(gsm, addr, 1, control); 635 } 636 637 /* Data transmission */ 638 639 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */ 640 641 /** 642 * gsm_data_alloc - allocate data frame 643 * @gsm: GSM mux 644 * @addr: DLCI address 645 * @len: length excluding header and FCS 646 * @ctrl: control byte 647 * 648 * Allocate a new data buffer for sending frames with data. Space is left 649 * at the front for header bytes but that is treated as an implementation 650 * detail and not for the high level code to use 651 */ 652 653 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len, 654 u8 ctrl) 655 { 656 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN, 657 GFP_ATOMIC); 658 if (m == NULL) 659 return NULL; 660 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */ 661 m->len = len; 662 m->addr = addr; 663 m->ctrl = ctrl; 664 INIT_LIST_HEAD(&m->list); 665 return m; 666 } 667 668 /** 669 * gsm_data_kick - poke the queue 670 * @gsm: GSM Mux 671 * 672 * The tty device has called us to indicate that room has appeared in 673 * the transmit queue. Ram more data into the pipe if we have any 674 * If we have been flow-stopped by a CMD_FCOFF, then we can only 675 * send messages on DLCI0 until CMD_FCON 676 * 677 * FIXME: lock against link layer control transmissions 678 */ 679 680 static void gsm_data_kick(struct gsm_mux *gsm) 681 { 682 struct gsm_msg *msg, *nmsg; 683 int len; 684 int skip_sof = 0; 685 686 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) { 687 if (gsm->constipated && msg->addr) 688 continue; 689 if (gsm->encoding != 0) { 690 gsm->txframe[0] = GSM1_SOF; 691 len = gsm_stuff_frame(msg->data, 692 gsm->txframe + 1, msg->len); 693 gsm->txframe[len + 1] = GSM1_SOF; 694 len += 2; 695 } else { 696 gsm->txframe[0] = GSM0_SOF; 697 memcpy(gsm->txframe + 1 , msg->data, msg->len); 698 gsm->txframe[msg->len + 1] = GSM0_SOF; 699 len = msg->len + 2; 700 } 701 702 if (debug & 4) 703 print_hex_dump_bytes("gsm_data_kick: ", 704 DUMP_PREFIX_OFFSET, 705 gsm->txframe, len); 706 707 if (gsm->output(gsm, gsm->txframe + skip_sof, 708 len - skip_sof) < 0) 709 break; 710 /* FIXME: Can eliminate one SOF in many more cases */ 711 gsm->tx_bytes -= msg->len; 712 /* For a burst of frames skip the extra SOF within the 713 burst */ 714 skip_sof = 1; 715 716 list_del(&msg->list); 717 kfree(msg); 718 } 719 } 720 721 /** 722 * __gsm_data_queue - queue a UI or UIH frame 723 * @dlci: DLCI sending the data 724 * @msg: message queued 725 * 726 * Add data to the transmit queue and try and get stuff moving 727 * out of the mux tty if not already doing so. The Caller must hold 728 * the gsm tx lock. 729 */ 730 731 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) 732 { 733 struct gsm_mux *gsm = dlci->gsm; 734 u8 *dp = msg->data; 735 u8 *fcs = dp + msg->len; 736 737 /* Fill in the header */ 738 if (gsm->encoding == 0) { 739 if (msg->len < 128) 740 *--dp = (msg->len << 1) | EA; 741 else { 742 *--dp = (msg->len >> 7); /* bits 7 - 15 */ 743 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */ 744 } 745 } 746 747 *--dp = msg->ctrl; 748 if (gsm->initiator) 749 *--dp = (msg->addr << 2) | 2 | EA; 750 else 751 *--dp = (msg->addr << 2) | EA; 752 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp); 753 /* Ugly protocol layering violation */ 754 if (msg->ctrl == UI || msg->ctrl == (UI|PF)) 755 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len); 756 *fcs = 0xFF - *fcs; 757 758 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl, 759 msg->data, msg->len); 760 761 /* Move the header back and adjust the length, also allow for the FCS 762 now tacked on the end */ 763 msg->len += (msg->data - dp) + 1; 764 msg->data = dp; 765 766 /* Add to the actual output queue */ 767 list_add_tail(&msg->list, &gsm->tx_list); 768 gsm->tx_bytes += msg->len; 769 gsm_data_kick(gsm); 770 } 771 772 /** 773 * gsm_data_queue - queue a UI or UIH frame 774 * @dlci: DLCI sending the data 775 * @msg: message queued 776 * 777 * Add data to the transmit queue and try and get stuff moving 778 * out of the mux tty if not already doing so. Take the 779 * the gsm tx lock and dlci lock. 780 */ 781 782 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) 783 { 784 unsigned long flags; 785 spin_lock_irqsave(&dlci->gsm->tx_lock, flags); 786 __gsm_data_queue(dlci, msg); 787 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); 788 } 789 790 /** 791 * gsm_dlci_data_output - try and push data out of a DLCI 792 * @gsm: mux 793 * @dlci: the DLCI to pull data from 794 * 795 * Pull data from a DLCI and send it into the transmit queue if there 796 * is data. Keep to the MRU of the mux. This path handles the usual tty 797 * interface which is a byte stream with optional modem data. 798 * 799 * Caller must hold the tx_lock of the mux. 800 */ 801 802 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci) 803 { 804 struct gsm_msg *msg; 805 u8 *dp; 806 int len, total_size, size; 807 int h = dlci->adaption - 1; 808 809 total_size = 0; 810 while(1) { 811 len = kfifo_len(dlci->fifo); 812 if (len == 0) 813 return total_size; 814 815 /* MTU/MRU count only the data bits */ 816 if (len > gsm->mtu) 817 len = gsm->mtu; 818 819 size = len + h; 820 821 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); 822 /* FIXME: need a timer or something to kick this so it can't 823 get stuck with no work outstanding and no buffer free */ 824 if (msg == NULL) 825 return -ENOMEM; 826 dp = msg->data; 827 switch (dlci->adaption) { 828 case 1: /* Unstructured */ 829 break; 830 case 2: /* Unstructed with modem bits. Always one byte as we never 831 send inline break data */ 832 *dp++ = gsm_encode_modem(dlci); 833 break; 834 } 835 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len); 836 __gsm_data_queue(dlci, msg); 837 total_size += size; 838 } 839 /* Bytes of data we used up */ 840 return total_size; 841 } 842 843 /** 844 * gsm_dlci_data_output_framed - try and push data out of a DLCI 845 * @gsm: mux 846 * @dlci: the DLCI to pull data from 847 * 848 * Pull data from a DLCI and send it into the transmit queue if there 849 * is data. Keep to the MRU of the mux. This path handles framed data 850 * queued as skbuffs to the DLCI. 851 * 852 * Caller must hold the tx_lock of the mux. 853 */ 854 855 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, 856 struct gsm_dlci *dlci) 857 { 858 struct gsm_msg *msg; 859 u8 *dp; 860 int len, size; 861 int last = 0, first = 0; 862 int overhead = 0; 863 864 /* One byte per frame is used for B/F flags */ 865 if (dlci->adaption == 4) 866 overhead = 1; 867 868 /* dlci->skb is locked by tx_lock */ 869 if (dlci->skb == NULL) { 870 dlci->skb = skb_dequeue_tail(&dlci->skb_list); 871 if (dlci->skb == NULL) 872 return 0; 873 first = 1; 874 } 875 len = dlci->skb->len + overhead; 876 877 /* MTU/MRU count only the data bits */ 878 if (len > gsm->mtu) { 879 if (dlci->adaption == 3) { 880 /* Over long frame, bin it */ 881 dev_kfree_skb_any(dlci->skb); 882 dlci->skb = NULL; 883 return 0; 884 } 885 len = gsm->mtu; 886 } else 887 last = 1; 888 889 size = len + overhead; 890 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); 891 892 /* FIXME: need a timer or something to kick this so it can't 893 get stuck with no work outstanding and no buffer free */ 894 if (msg == NULL) { 895 skb_queue_tail(&dlci->skb_list, dlci->skb); 896 dlci->skb = NULL; 897 return -ENOMEM; 898 } 899 dp = msg->data; 900 901 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */ 902 /* Flag byte to carry the start/end info */ 903 *dp++ = last << 7 | first << 6 | 1; /* EA */ 904 len--; 905 } 906 memcpy(dp, dlci->skb->data, len); 907 skb_pull(dlci->skb, len); 908 __gsm_data_queue(dlci, msg); 909 if (last) { 910 dev_kfree_skb_any(dlci->skb); 911 dlci->skb = NULL; 912 } 913 return size; 914 } 915 916 /** 917 * gsm_dlci_data_sweep - look for data to send 918 * @gsm: the GSM mux 919 * 920 * Sweep the GSM mux channels in priority order looking for ones with 921 * data to send. We could do with optimising this scan a bit. We aim 922 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit 923 * TX_THRESH_LO we get called again 924 * 925 * FIXME: We should round robin between groups and in theory you can 926 * renegotiate DLCI priorities with optional stuff. Needs optimising. 927 */ 928 929 static void gsm_dlci_data_sweep(struct gsm_mux *gsm) 930 { 931 int len; 932 /* Priority ordering: We should do priority with RR of the groups */ 933 int i = 1; 934 935 while (i < NUM_DLCI) { 936 struct gsm_dlci *dlci; 937 938 if (gsm->tx_bytes > TX_THRESH_HI) 939 break; 940 dlci = gsm->dlci[i]; 941 if (dlci == NULL || dlci->constipated) { 942 i++; 943 continue; 944 } 945 if (dlci->adaption < 3 && !dlci->net) 946 len = gsm_dlci_data_output(gsm, dlci); 947 else 948 len = gsm_dlci_data_output_framed(gsm, dlci); 949 if (len < 0) 950 break; 951 /* DLCI empty - try the next */ 952 if (len == 0) 953 i++; 954 } 955 } 956 957 /** 958 * gsm_dlci_data_kick - transmit if possible 959 * @dlci: DLCI to kick 960 * 961 * Transmit data from this DLCI if the queue is empty. We can't rely on 962 * a tty wakeup except when we filled the pipe so we need to fire off 963 * new data ourselves in other cases. 964 */ 965 966 static void gsm_dlci_data_kick(struct gsm_dlci *dlci) 967 { 968 unsigned long flags; 969 int sweep; 970 971 if (dlci->constipated) 972 return; 973 974 spin_lock_irqsave(&dlci->gsm->tx_lock, flags); 975 /* If we have nothing running then we need to fire up */ 976 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO); 977 if (dlci->gsm->tx_bytes == 0) { 978 if (dlci->net) 979 gsm_dlci_data_output_framed(dlci->gsm, dlci); 980 else 981 gsm_dlci_data_output(dlci->gsm, dlci); 982 } 983 if (sweep) 984 gsm_dlci_data_sweep(dlci->gsm); 985 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); 986 } 987 988 /* 989 * Control message processing 990 */ 991 992 993 /** 994 * gsm_control_reply - send a response frame to a control 995 * @gsm: gsm channel 996 * @cmd: the command to use 997 * @data: data to follow encoded info 998 * @dlen: length of data 999 * 1000 * Encode up and queue a UI/UIH frame containing our response. 1001 */ 1002 1003 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data, 1004 int dlen) 1005 { 1006 struct gsm_msg *msg; 1007 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype); 1008 if (msg == NULL) 1009 return; 1010 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */ 1011 msg->data[1] = (dlen << 1) | EA; 1012 memcpy(msg->data + 2, data, dlen); 1013 gsm_data_queue(gsm->dlci[0], msg); 1014 } 1015 1016 /** 1017 * gsm_process_modem - process received modem status 1018 * @tty: virtual tty bound to the DLCI 1019 * @dlci: DLCI to affect 1020 * @modem: modem bits (full EA) 1021 * 1022 * Used when a modem control message or line state inline in adaption 1023 * layer 2 is processed. Sort out the local modem state and throttles 1024 */ 1025 1026 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci, 1027 u32 modem, int clen) 1028 { 1029 int mlines = 0; 1030 u8 brk = 0; 1031 int fc; 1032 1033 /* The modem status command can either contain one octet (v.24 signals) 1034 or two octets (v.24 signals + break signals). The length field will 1035 either be 2 or 3 respectively. This is specified in section 1036 5.4.6.3.7 of the 27.010 mux spec. */ 1037 1038 if (clen == 2) 1039 modem = modem & 0x7f; 1040 else { 1041 brk = modem & 0x7f; 1042 modem = (modem >> 7) & 0x7f; 1043 } 1044 1045 /* Flow control/ready to communicate */ 1046 fc = (modem & MDM_FC) || !(modem & MDM_RTR); 1047 if (fc && !dlci->constipated) { 1048 /* Need to throttle our output on this device */ 1049 dlci->constipated = 1; 1050 } else if (!fc && dlci->constipated) { 1051 dlci->constipated = 0; 1052 gsm_dlci_data_kick(dlci); 1053 } 1054 1055 /* Map modem bits */ 1056 if (modem & MDM_RTC) 1057 mlines |= TIOCM_DSR | TIOCM_DTR; 1058 if (modem & MDM_RTR) 1059 mlines |= TIOCM_RTS | TIOCM_CTS; 1060 if (modem & MDM_IC) 1061 mlines |= TIOCM_RI; 1062 if (modem & MDM_DV) 1063 mlines |= TIOCM_CD; 1064 1065 /* Carrier drop -> hangup */ 1066 if (tty) { 1067 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD)) 1068 if (!(tty->termios.c_cflag & CLOCAL)) 1069 tty_hangup(tty); 1070 } 1071 if (brk & 0x01) 1072 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK); 1073 dlci->modem_rx = mlines; 1074 } 1075 1076 /** 1077 * gsm_control_modem - modem status received 1078 * @gsm: GSM channel 1079 * @data: data following command 1080 * @clen: command length 1081 * 1082 * We have received a modem status control message. This is used by 1083 * the GSM mux protocol to pass virtual modem line status and optionally 1084 * to indicate break signals. Unpack it, convert to Linux representation 1085 * and if need be stuff a break message down the tty. 1086 */ 1087 1088 static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen) 1089 { 1090 unsigned int addr = 0; 1091 unsigned int modem = 0; 1092 struct gsm_dlci *dlci; 1093 int len = clen; 1094 u8 *dp = data; 1095 struct tty_struct *tty; 1096 1097 while (gsm_read_ea(&addr, *dp++) == 0) { 1098 len--; 1099 if (len == 0) 1100 return; 1101 } 1102 /* Must be at least one byte following the EA */ 1103 len--; 1104 if (len <= 0) 1105 return; 1106 1107 addr >>= 1; 1108 /* Closed port, or invalid ? */ 1109 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) 1110 return; 1111 dlci = gsm->dlci[addr]; 1112 1113 while (gsm_read_ea(&modem, *dp++) == 0) { 1114 len--; 1115 if (len == 0) 1116 return; 1117 } 1118 tty = tty_port_tty_get(&dlci->port); 1119 gsm_process_modem(tty, dlci, modem, clen); 1120 if (tty) { 1121 tty_wakeup(tty); 1122 tty_kref_put(tty); 1123 } 1124 gsm_control_reply(gsm, CMD_MSC, data, clen); 1125 } 1126 1127 /** 1128 * gsm_control_rls - remote line status 1129 * @gsm: GSM channel 1130 * @data: data bytes 1131 * @clen: data length 1132 * 1133 * The modem sends us a two byte message on the control channel whenever 1134 * it wishes to send us an error state from the virtual link. Stuff 1135 * this into the uplink tty if present 1136 */ 1137 1138 static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen) 1139 { 1140 struct tty_port *port; 1141 unsigned int addr = 0 ; 1142 u8 bits; 1143 int len = clen; 1144 u8 *dp = data; 1145 1146 while (gsm_read_ea(&addr, *dp++) == 0) { 1147 len--; 1148 if (len == 0) 1149 return; 1150 } 1151 /* Must be at least one byte following ea */ 1152 len--; 1153 if (len <= 0) 1154 return; 1155 addr >>= 1; 1156 /* Closed port, or invalid ? */ 1157 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) 1158 return; 1159 /* No error ? */ 1160 bits = *dp; 1161 if ((bits & 1) == 0) 1162 return; 1163 1164 port = &gsm->dlci[addr]->port; 1165 1166 if (bits & 2) 1167 tty_insert_flip_char(port, 0, TTY_OVERRUN); 1168 if (bits & 4) 1169 tty_insert_flip_char(port, 0, TTY_PARITY); 1170 if (bits & 8) 1171 tty_insert_flip_char(port, 0, TTY_FRAME); 1172 1173 tty_flip_buffer_push(port); 1174 1175 gsm_control_reply(gsm, CMD_RLS, data, clen); 1176 } 1177 1178 static void gsm_dlci_begin_close(struct gsm_dlci *dlci); 1179 1180 /** 1181 * gsm_control_message - DLCI 0 control processing 1182 * @gsm: our GSM mux 1183 * @command: the command EA 1184 * @data: data beyond the command/length EAs 1185 * @clen: length 1186 * 1187 * Input processor for control messages from the other end of the link. 1188 * Processes the incoming request and queues a response frame or an 1189 * NSC response if not supported 1190 */ 1191 1192 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, 1193 u8 *data, int clen) 1194 { 1195 u8 buf[1]; 1196 unsigned long flags; 1197 1198 switch (command) { 1199 case CMD_CLD: { 1200 struct gsm_dlci *dlci = gsm->dlci[0]; 1201 /* Modem wishes to close down */ 1202 if (dlci) { 1203 dlci->dead = 1; 1204 gsm->dead = 1; 1205 gsm_dlci_begin_close(dlci); 1206 } 1207 } 1208 break; 1209 case CMD_TEST: 1210 /* Modem wishes to test, reply with the data */ 1211 gsm_control_reply(gsm, CMD_TEST, data, clen); 1212 break; 1213 case CMD_FCON: 1214 /* Modem can accept data again */ 1215 gsm->constipated = 0; 1216 gsm_control_reply(gsm, CMD_FCON, NULL, 0); 1217 /* Kick the link in case it is idling */ 1218 spin_lock_irqsave(&gsm->tx_lock, flags); 1219 gsm_data_kick(gsm); 1220 spin_unlock_irqrestore(&gsm->tx_lock, flags); 1221 break; 1222 case CMD_FCOFF: 1223 /* Modem wants us to STFU */ 1224 gsm->constipated = 1; 1225 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0); 1226 break; 1227 case CMD_MSC: 1228 /* Out of band modem line change indicator for a DLCI */ 1229 gsm_control_modem(gsm, data, clen); 1230 break; 1231 case CMD_RLS: 1232 /* Out of band error reception for a DLCI */ 1233 gsm_control_rls(gsm, data, clen); 1234 break; 1235 case CMD_PSC: 1236 /* Modem wishes to enter power saving state */ 1237 gsm_control_reply(gsm, CMD_PSC, NULL, 0); 1238 break; 1239 /* Optional unsupported commands */ 1240 case CMD_PN: /* Parameter negotiation */ 1241 case CMD_RPN: /* Remote port negotiation */ 1242 case CMD_SNC: /* Service negotiation command */ 1243 default: 1244 /* Reply to bad commands with an NSC */ 1245 buf[0] = command; 1246 gsm_control_reply(gsm, CMD_NSC, buf, 1); 1247 break; 1248 } 1249 } 1250 1251 /** 1252 * gsm_control_response - process a response to our control 1253 * @gsm: our GSM mux 1254 * @command: the command (response) EA 1255 * @data: data beyond the command/length EA 1256 * @clen: length 1257 * 1258 * Process a response to an outstanding command. We only allow a single 1259 * control message in flight so this is fairly easy. All the clean up 1260 * is done by the caller, we just update the fields, flag it as done 1261 * and return 1262 */ 1263 1264 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command, 1265 u8 *data, int clen) 1266 { 1267 struct gsm_control *ctrl; 1268 unsigned long flags; 1269 1270 spin_lock_irqsave(&gsm->control_lock, flags); 1271 1272 ctrl = gsm->pending_cmd; 1273 /* Does the reply match our command */ 1274 command |= 1; 1275 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) { 1276 /* Our command was replied to, kill the retry timer */ 1277 del_timer(&gsm->t2_timer); 1278 gsm->pending_cmd = NULL; 1279 /* Rejected by the other end */ 1280 if (command == CMD_NSC) 1281 ctrl->error = -EOPNOTSUPP; 1282 ctrl->done = 1; 1283 wake_up(&gsm->event); 1284 } 1285 spin_unlock_irqrestore(&gsm->control_lock, flags); 1286 } 1287 1288 /** 1289 * gsm_control_transmit - send control packet 1290 * @gsm: gsm mux 1291 * @ctrl: frame to send 1292 * 1293 * Send out a pending control command (called under control lock) 1294 */ 1295 1296 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl) 1297 { 1298 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype); 1299 if (msg == NULL) 1300 return; 1301 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */ 1302 memcpy(msg->data + 1, ctrl->data, ctrl->len); 1303 gsm_data_queue(gsm->dlci[0], msg); 1304 } 1305 1306 /** 1307 * gsm_control_retransmit - retransmit a control frame 1308 * @data: pointer to our gsm object 1309 * 1310 * Called off the T2 timer expiry in order to retransmit control frames 1311 * that have been lost in the system somewhere. The control_lock protects 1312 * us from colliding with another sender or a receive completion event. 1313 * In that situation the timer may still occur in a small window but 1314 * gsm->pending_cmd will be NULL and we just let the timer expire. 1315 */ 1316 1317 static void gsm_control_retransmit(unsigned long data) 1318 { 1319 struct gsm_mux *gsm = (struct gsm_mux *)data; 1320 struct gsm_control *ctrl; 1321 unsigned long flags; 1322 spin_lock_irqsave(&gsm->control_lock, flags); 1323 ctrl = gsm->pending_cmd; 1324 if (ctrl) { 1325 gsm->cretries--; 1326 if (gsm->cretries == 0) { 1327 gsm->pending_cmd = NULL; 1328 ctrl->error = -ETIMEDOUT; 1329 ctrl->done = 1; 1330 spin_unlock_irqrestore(&gsm->control_lock, flags); 1331 wake_up(&gsm->event); 1332 return; 1333 } 1334 gsm_control_transmit(gsm, ctrl); 1335 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); 1336 } 1337 spin_unlock_irqrestore(&gsm->control_lock, flags); 1338 } 1339 1340 /** 1341 * gsm_control_send - send a control frame on DLCI 0 1342 * @gsm: the GSM channel 1343 * @command: command to send including CR bit 1344 * @data: bytes of data (must be kmalloced) 1345 * @len: length of the block to send 1346 * 1347 * Queue and dispatch a control command. Only one command can be 1348 * active at a time. In theory more can be outstanding but the matching 1349 * gets really complicated so for now stick to one outstanding. 1350 */ 1351 1352 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm, 1353 unsigned int command, u8 *data, int clen) 1354 { 1355 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control), 1356 GFP_KERNEL); 1357 unsigned long flags; 1358 if (ctrl == NULL) 1359 return NULL; 1360 retry: 1361 wait_event(gsm->event, gsm->pending_cmd == NULL); 1362 spin_lock_irqsave(&gsm->control_lock, flags); 1363 if (gsm->pending_cmd != NULL) { 1364 spin_unlock_irqrestore(&gsm->control_lock, flags); 1365 goto retry; 1366 } 1367 ctrl->cmd = command; 1368 ctrl->data = data; 1369 ctrl->len = clen; 1370 gsm->pending_cmd = ctrl; 1371 gsm->cretries = gsm->n2; 1372 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); 1373 gsm_control_transmit(gsm, ctrl); 1374 spin_unlock_irqrestore(&gsm->control_lock, flags); 1375 return ctrl; 1376 } 1377 1378 /** 1379 * gsm_control_wait - wait for a control to finish 1380 * @gsm: GSM mux 1381 * @control: control we are waiting on 1382 * 1383 * Waits for the control to complete or time out. Frees any used 1384 * resources and returns 0 for success, or an error if the remote 1385 * rejected or ignored the request. 1386 */ 1387 1388 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control) 1389 { 1390 int err; 1391 wait_event(gsm->event, control->done == 1); 1392 err = control->error; 1393 kfree(control); 1394 return err; 1395 } 1396 1397 1398 /* 1399 * DLCI level handling: Needs krefs 1400 */ 1401 1402 /* 1403 * State transitions and timers 1404 */ 1405 1406 /** 1407 * gsm_dlci_close - a DLCI has closed 1408 * @dlci: DLCI that closed 1409 * 1410 * Perform processing when moving a DLCI into closed state. If there 1411 * is an attached tty this is hung up 1412 */ 1413 1414 static void gsm_dlci_close(struct gsm_dlci *dlci) 1415 { 1416 del_timer(&dlci->t1); 1417 if (debug & 8) 1418 pr_debug("DLCI %d goes closed.\n", dlci->addr); 1419 dlci->state = DLCI_CLOSED; 1420 if (dlci->addr != 0) { 1421 struct tty_struct *tty = tty_port_tty_get(&dlci->port); 1422 if (tty) { 1423 tty_hangup(tty); 1424 tty_kref_put(tty); 1425 } 1426 kfifo_reset(dlci->fifo); 1427 } else 1428 dlci->gsm->dead = 1; 1429 wake_up(&dlci->gsm->event); 1430 /* A DLCI 0 close is a MUX termination so we need to kick that 1431 back to userspace somehow */ 1432 } 1433 1434 /** 1435 * gsm_dlci_open - a DLCI has opened 1436 * @dlci: DLCI that opened 1437 * 1438 * Perform processing when moving a DLCI into open state. 1439 */ 1440 1441 static void gsm_dlci_open(struct gsm_dlci *dlci) 1442 { 1443 /* Note that SABM UA .. SABM UA first UA lost can mean that we go 1444 open -> open */ 1445 del_timer(&dlci->t1); 1446 /* This will let a tty open continue */ 1447 dlci->state = DLCI_OPEN; 1448 if (debug & 8) 1449 pr_debug("DLCI %d goes open.\n", dlci->addr); 1450 wake_up(&dlci->gsm->event); 1451 } 1452 1453 /** 1454 * gsm_dlci_t1 - T1 timer expiry 1455 * @dlci: DLCI that opened 1456 * 1457 * The T1 timer handles retransmits of control frames (essentially of 1458 * SABM and DISC). We resend the command until the retry count runs out 1459 * in which case an opening port goes back to closed and a closing port 1460 * is simply put into closed state (any further frames from the other 1461 * end will get a DM response) 1462 */ 1463 1464 static void gsm_dlci_t1(unsigned long data) 1465 { 1466 struct gsm_dlci *dlci = (struct gsm_dlci *)data; 1467 struct gsm_mux *gsm = dlci->gsm; 1468 1469 switch (dlci->state) { 1470 case DLCI_OPENING: 1471 dlci->retries--; 1472 if (dlci->retries) { 1473 gsm_command(dlci->gsm, dlci->addr, SABM|PF); 1474 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1475 } else 1476 gsm_dlci_close(dlci); 1477 break; 1478 case DLCI_CLOSING: 1479 dlci->retries--; 1480 if (dlci->retries) { 1481 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 1482 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1483 } else 1484 gsm_dlci_close(dlci); 1485 break; 1486 } 1487 } 1488 1489 /** 1490 * gsm_dlci_begin_open - start channel open procedure 1491 * @dlci: DLCI to open 1492 * 1493 * Commence opening a DLCI from the Linux side. We issue SABM messages 1494 * to the modem which should then reply with a UA, at which point we 1495 * will move into open state. Opening is done asynchronously with retry 1496 * running off timers and the responses. 1497 */ 1498 1499 static void gsm_dlci_begin_open(struct gsm_dlci *dlci) 1500 { 1501 struct gsm_mux *gsm = dlci->gsm; 1502 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING) 1503 return; 1504 dlci->retries = gsm->n2; 1505 dlci->state = DLCI_OPENING; 1506 gsm_command(dlci->gsm, dlci->addr, SABM|PF); 1507 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1508 } 1509 1510 /** 1511 * gsm_dlci_begin_close - start channel open procedure 1512 * @dlci: DLCI to open 1513 * 1514 * Commence closing a DLCI from the Linux side. We issue DISC messages 1515 * to the modem which should then reply with a UA, at which point we 1516 * will move into closed state. Closing is done asynchronously with retry 1517 * off timers. We may also receive a DM reply from the other end which 1518 * indicates the channel was already closed. 1519 */ 1520 1521 static void gsm_dlci_begin_close(struct gsm_dlci *dlci) 1522 { 1523 struct gsm_mux *gsm = dlci->gsm; 1524 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING) 1525 return; 1526 dlci->retries = gsm->n2; 1527 dlci->state = DLCI_CLOSING; 1528 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 1529 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1530 } 1531 1532 /** 1533 * gsm_dlci_data - data arrived 1534 * @dlci: channel 1535 * @data: block of bytes received 1536 * @len: length of received block 1537 * 1538 * A UI or UIH frame has arrived which contains data for a channel 1539 * other than the control channel. If the relevant virtual tty is 1540 * open we shovel the bits down it, if not we drop them. 1541 */ 1542 1543 static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen) 1544 { 1545 /* krefs .. */ 1546 struct tty_port *port = &dlci->port; 1547 struct tty_struct *tty; 1548 unsigned int modem = 0; 1549 int len = clen; 1550 1551 if (debug & 16) 1552 pr_debug("%d bytes for tty\n", len); 1553 switch (dlci->adaption) { 1554 /* Unsupported types */ 1555 /* Packetised interruptible data */ 1556 case 4: 1557 break; 1558 /* Packetised uininterruptible voice/data */ 1559 case 3: 1560 break; 1561 /* Asynchronous serial with line state in each frame */ 1562 case 2: 1563 while (gsm_read_ea(&modem, *data++) == 0) { 1564 len--; 1565 if (len == 0) 1566 return; 1567 } 1568 tty = tty_port_tty_get(port); 1569 if (tty) { 1570 gsm_process_modem(tty, dlci, modem, clen); 1571 tty_kref_put(tty); 1572 } 1573 /* Line state will go via DLCI 0 controls only */ 1574 case 1: 1575 default: 1576 tty_insert_flip_string(port, data, len); 1577 tty_flip_buffer_push(port); 1578 } 1579 } 1580 1581 /** 1582 * gsm_dlci_control - data arrived on control channel 1583 * @dlci: channel 1584 * @data: block of bytes received 1585 * @len: length of received block 1586 * 1587 * A UI or UIH frame has arrived which contains data for DLCI 0 the 1588 * control channel. This should contain a command EA followed by 1589 * control data bytes. The command EA contains a command/response bit 1590 * and we divide up the work accordingly. 1591 */ 1592 1593 static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len) 1594 { 1595 /* See what command is involved */ 1596 unsigned int command = 0; 1597 while (len-- > 0) { 1598 if (gsm_read_ea(&command, *data++) == 1) { 1599 int clen = *data++; 1600 len--; 1601 /* FIXME: this is properly an EA */ 1602 clen >>= 1; 1603 /* Malformed command ? */ 1604 if (clen > len) 1605 return; 1606 if (command & 1) 1607 gsm_control_message(dlci->gsm, command, 1608 data, clen); 1609 else 1610 gsm_control_response(dlci->gsm, command, 1611 data, clen); 1612 return; 1613 } 1614 } 1615 } 1616 1617 /* 1618 * Allocate/Free DLCI channels 1619 */ 1620 1621 /** 1622 * gsm_dlci_alloc - allocate a DLCI 1623 * @gsm: GSM mux 1624 * @addr: address of the DLCI 1625 * 1626 * Allocate and install a new DLCI object into the GSM mux. 1627 * 1628 * FIXME: review locking races 1629 */ 1630 1631 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr) 1632 { 1633 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC); 1634 if (dlci == NULL) 1635 return NULL; 1636 spin_lock_init(&dlci->lock); 1637 mutex_init(&dlci->mutex); 1638 dlci->fifo = &dlci->_fifo; 1639 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) { 1640 kfree(dlci); 1641 return NULL; 1642 } 1643 1644 skb_queue_head_init(&dlci->skb_list); 1645 init_timer(&dlci->t1); 1646 dlci->t1.function = gsm_dlci_t1; 1647 dlci->t1.data = (unsigned long)dlci; 1648 tty_port_init(&dlci->port); 1649 dlci->port.ops = &gsm_port_ops; 1650 dlci->gsm = gsm; 1651 dlci->addr = addr; 1652 dlci->adaption = gsm->adaption; 1653 dlci->state = DLCI_CLOSED; 1654 if (addr) 1655 dlci->data = gsm_dlci_data; 1656 else 1657 dlci->data = gsm_dlci_command; 1658 gsm->dlci[addr] = dlci; 1659 return dlci; 1660 } 1661 1662 /** 1663 * gsm_dlci_free - free DLCI 1664 * @dlci: DLCI to free 1665 * 1666 * Free up a DLCI. 1667 * 1668 * Can sleep. 1669 */ 1670 static void gsm_dlci_free(struct tty_port *port) 1671 { 1672 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 1673 1674 del_timer_sync(&dlci->t1); 1675 dlci->gsm->dlci[dlci->addr] = NULL; 1676 kfifo_free(dlci->fifo); 1677 while ((dlci->skb = skb_dequeue(&dlci->skb_list))) 1678 dev_kfree_skb(dlci->skb); 1679 kfree(dlci); 1680 } 1681 1682 static inline void dlci_get(struct gsm_dlci *dlci) 1683 { 1684 tty_port_get(&dlci->port); 1685 } 1686 1687 static inline void dlci_put(struct gsm_dlci *dlci) 1688 { 1689 tty_port_put(&dlci->port); 1690 } 1691 1692 static void gsm_destroy_network(struct gsm_dlci *dlci); 1693 1694 /** 1695 * gsm_dlci_release - release DLCI 1696 * @dlci: DLCI to destroy 1697 * 1698 * Release a DLCI. Actual free is deferred until either 1699 * mux is closed or tty is closed - whichever is last. 1700 * 1701 * Can sleep. 1702 */ 1703 static void gsm_dlci_release(struct gsm_dlci *dlci) 1704 { 1705 struct tty_struct *tty = tty_port_tty_get(&dlci->port); 1706 if (tty) { 1707 mutex_lock(&dlci->mutex); 1708 gsm_destroy_network(dlci); 1709 mutex_unlock(&dlci->mutex); 1710 1711 /* tty_vhangup needs the tty_lock, so unlock and 1712 relock after doing the hangup. */ 1713 tty_unlock(tty); 1714 tty_vhangup(tty); 1715 tty_lock(tty); 1716 tty_port_tty_set(&dlci->port, NULL); 1717 tty_kref_put(tty); 1718 } 1719 dlci->state = DLCI_CLOSED; 1720 dlci_put(dlci); 1721 } 1722 1723 /* 1724 * LAPBish link layer logic 1725 */ 1726 1727 /** 1728 * gsm_queue - a GSM frame is ready to process 1729 * @gsm: pointer to our gsm mux 1730 * 1731 * At this point in time a frame has arrived and been demangled from 1732 * the line encoding. All the differences between the encodings have 1733 * been handled below us and the frame is unpacked into the structures. 1734 * The fcs holds the header FCS but any data FCS must be added here. 1735 */ 1736 1737 static void gsm_queue(struct gsm_mux *gsm) 1738 { 1739 struct gsm_dlci *dlci; 1740 u8 cr; 1741 int address; 1742 /* We have to sneak a look at the packet body to do the FCS. 1743 A somewhat layering violation in the spec */ 1744 1745 if ((gsm->control & ~PF) == UI) 1746 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len); 1747 if (gsm->encoding == 0){ 1748 /* WARNING: gsm->received_fcs is used for gsm->encoding = 0 only. 1749 In this case it contain the last piece of data 1750 required to generate final CRC */ 1751 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs); 1752 } 1753 if (gsm->fcs != GOOD_FCS) { 1754 gsm->bad_fcs++; 1755 if (debug & 4) 1756 pr_debug("BAD FCS %02x\n", gsm->fcs); 1757 return; 1758 } 1759 address = gsm->address >> 1; 1760 if (address >= NUM_DLCI) 1761 goto invalid; 1762 1763 cr = gsm->address & 1; /* C/R bit */ 1764 1765 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len); 1766 1767 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */ 1768 dlci = gsm->dlci[address]; 1769 1770 switch (gsm->control) { 1771 case SABM|PF: 1772 if (cr == 0) 1773 goto invalid; 1774 if (dlci == NULL) 1775 dlci = gsm_dlci_alloc(gsm, address); 1776 if (dlci == NULL) 1777 return; 1778 if (dlci->dead) 1779 gsm_response(gsm, address, DM); 1780 else { 1781 gsm_response(gsm, address, UA); 1782 gsm_dlci_open(dlci); 1783 } 1784 break; 1785 case DISC|PF: 1786 if (cr == 0) 1787 goto invalid; 1788 if (dlci == NULL || dlci->state == DLCI_CLOSED) { 1789 gsm_response(gsm, address, DM); 1790 return; 1791 } 1792 /* Real close complete */ 1793 gsm_response(gsm, address, UA); 1794 gsm_dlci_close(dlci); 1795 break; 1796 case UA: 1797 case UA|PF: 1798 if (cr == 0 || dlci == NULL) 1799 break; 1800 switch (dlci->state) { 1801 case DLCI_CLOSING: 1802 gsm_dlci_close(dlci); 1803 break; 1804 case DLCI_OPENING: 1805 gsm_dlci_open(dlci); 1806 break; 1807 } 1808 break; 1809 case DM: /* DM can be valid unsolicited */ 1810 case DM|PF: 1811 if (cr) 1812 goto invalid; 1813 if (dlci == NULL) 1814 return; 1815 gsm_dlci_close(dlci); 1816 break; 1817 case UI: 1818 case UI|PF: 1819 case UIH: 1820 case UIH|PF: 1821 #if 0 1822 if (cr) 1823 goto invalid; 1824 #endif 1825 if (dlci == NULL || dlci->state != DLCI_OPEN) { 1826 gsm_command(gsm, address, DM|PF); 1827 return; 1828 } 1829 dlci->data(dlci, gsm->buf, gsm->len); 1830 break; 1831 default: 1832 goto invalid; 1833 } 1834 return; 1835 invalid: 1836 gsm->malformed++; 1837 return; 1838 } 1839 1840 1841 /** 1842 * gsm0_receive - perform processing for non-transparency 1843 * @gsm: gsm data for this ldisc instance 1844 * @c: character 1845 * 1846 * Receive bytes in gsm mode 0 1847 */ 1848 1849 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) 1850 { 1851 unsigned int len; 1852 1853 switch (gsm->state) { 1854 case GSM_SEARCH: /* SOF marker */ 1855 if (c == GSM0_SOF) { 1856 gsm->state = GSM_ADDRESS; 1857 gsm->address = 0; 1858 gsm->len = 0; 1859 gsm->fcs = INIT_FCS; 1860 } 1861 break; 1862 case GSM_ADDRESS: /* Address EA */ 1863 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1864 if (gsm_read_ea(&gsm->address, c)) 1865 gsm->state = GSM_CONTROL; 1866 break; 1867 case GSM_CONTROL: /* Control Byte */ 1868 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1869 gsm->control = c; 1870 gsm->state = GSM_LEN0; 1871 break; 1872 case GSM_LEN0: /* Length EA */ 1873 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1874 if (gsm_read_ea(&gsm->len, c)) { 1875 if (gsm->len > gsm->mru) { 1876 gsm->bad_size++; 1877 gsm->state = GSM_SEARCH; 1878 break; 1879 } 1880 gsm->count = 0; 1881 if (!gsm->len) 1882 gsm->state = GSM_FCS; 1883 else 1884 gsm->state = GSM_DATA; 1885 break; 1886 } 1887 gsm->state = GSM_LEN1; 1888 break; 1889 case GSM_LEN1: 1890 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1891 len = c; 1892 gsm->len |= len << 7; 1893 if (gsm->len > gsm->mru) { 1894 gsm->bad_size++; 1895 gsm->state = GSM_SEARCH; 1896 break; 1897 } 1898 gsm->count = 0; 1899 if (!gsm->len) 1900 gsm->state = GSM_FCS; 1901 else 1902 gsm->state = GSM_DATA; 1903 break; 1904 case GSM_DATA: /* Data */ 1905 gsm->buf[gsm->count++] = c; 1906 if (gsm->count == gsm->len) 1907 gsm->state = GSM_FCS; 1908 break; 1909 case GSM_FCS: /* FCS follows the packet */ 1910 gsm->received_fcs = c; 1911 gsm_queue(gsm); 1912 gsm->state = GSM_SSOF; 1913 break; 1914 case GSM_SSOF: 1915 if (c == GSM0_SOF) { 1916 gsm->state = GSM_SEARCH; 1917 break; 1918 } 1919 break; 1920 } 1921 } 1922 1923 /** 1924 * gsm1_receive - perform processing for non-transparency 1925 * @gsm: gsm data for this ldisc instance 1926 * @c: character 1927 * 1928 * Receive bytes in mode 1 (Advanced option) 1929 */ 1930 1931 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c) 1932 { 1933 if (c == GSM1_SOF) { 1934 /* EOF is only valid in frame if we have got to the data state 1935 and received at least one byte (the FCS) */ 1936 if (gsm->state == GSM_DATA && gsm->count) { 1937 /* Extract the FCS */ 1938 gsm->count--; 1939 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]); 1940 gsm->len = gsm->count; 1941 gsm_queue(gsm); 1942 gsm->state = GSM_START; 1943 return; 1944 } 1945 /* Any partial frame was a runt so go back to start */ 1946 if (gsm->state != GSM_START) { 1947 gsm->malformed++; 1948 gsm->state = GSM_START; 1949 } 1950 /* A SOF in GSM_START means we are still reading idling or 1951 framing bytes */ 1952 return; 1953 } 1954 1955 if (c == GSM1_ESCAPE) { 1956 gsm->escape = 1; 1957 return; 1958 } 1959 1960 /* Only an unescaped SOF gets us out of GSM search */ 1961 if (gsm->state == GSM_SEARCH) 1962 return; 1963 1964 if (gsm->escape) { 1965 c ^= GSM1_ESCAPE_BITS; 1966 gsm->escape = 0; 1967 } 1968 switch (gsm->state) { 1969 case GSM_START: /* First byte after SOF */ 1970 gsm->address = 0; 1971 gsm->state = GSM_ADDRESS; 1972 gsm->fcs = INIT_FCS; 1973 /* Drop through */ 1974 case GSM_ADDRESS: /* Address continuation */ 1975 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1976 if (gsm_read_ea(&gsm->address, c)) 1977 gsm->state = GSM_CONTROL; 1978 break; 1979 case GSM_CONTROL: /* Control Byte */ 1980 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1981 gsm->control = c; 1982 gsm->count = 0; 1983 gsm->state = GSM_DATA; 1984 break; 1985 case GSM_DATA: /* Data */ 1986 if (gsm->count > gsm->mru) { /* Allow one for the FCS */ 1987 gsm->state = GSM_OVERRUN; 1988 gsm->bad_size++; 1989 } else 1990 gsm->buf[gsm->count++] = c; 1991 break; 1992 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */ 1993 break; 1994 } 1995 } 1996 1997 /** 1998 * gsm_error - handle tty error 1999 * @gsm: ldisc data 2000 * @data: byte received (may be invalid) 2001 * @flag: error received 2002 * 2003 * Handle an error in the receipt of data for a frame. Currently we just 2004 * go back to hunting for a SOF. 2005 * 2006 * FIXME: better diagnostics ? 2007 */ 2008 2009 static void gsm_error(struct gsm_mux *gsm, 2010 unsigned char data, unsigned char flag) 2011 { 2012 gsm->state = GSM_SEARCH; 2013 gsm->io_error++; 2014 } 2015 2016 /** 2017 * gsm_cleanup_mux - generic GSM protocol cleanup 2018 * @gsm: our mux 2019 * 2020 * Clean up the bits of the mux which are the same for all framing 2021 * protocols. Remove the mux from the mux table, stop all the timers 2022 * and then shut down each device hanging up the channels as we go. 2023 */ 2024 2025 void gsm_cleanup_mux(struct gsm_mux *gsm) 2026 { 2027 int i; 2028 struct gsm_dlci *dlci = gsm->dlci[0]; 2029 struct gsm_msg *txq, *ntxq; 2030 struct gsm_control *gc; 2031 2032 gsm->dead = 1; 2033 2034 spin_lock(&gsm_mux_lock); 2035 for (i = 0; i < MAX_MUX; i++) { 2036 if (gsm_mux[i] == gsm) { 2037 gsm_mux[i] = NULL; 2038 break; 2039 } 2040 } 2041 spin_unlock(&gsm_mux_lock); 2042 WARN_ON(i == MAX_MUX); 2043 2044 /* In theory disconnecting DLCI 0 is sufficient but for some 2045 modems this is apparently not the case. */ 2046 if (dlci) { 2047 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0); 2048 if (gc) 2049 gsm_control_wait(gsm, gc); 2050 } 2051 del_timer_sync(&gsm->t2_timer); 2052 /* Now we are sure T2 has stopped */ 2053 if (dlci) { 2054 dlci->dead = 1; 2055 gsm_dlci_begin_close(dlci); 2056 wait_event_interruptible(gsm->event, 2057 dlci->state == DLCI_CLOSED); 2058 } 2059 /* Free up any link layer users */ 2060 for (i = 0; i < NUM_DLCI; i++) 2061 if (gsm->dlci[i]) 2062 gsm_dlci_release(gsm->dlci[i]); 2063 /* Now wipe the queues */ 2064 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list) 2065 kfree(txq); 2066 INIT_LIST_HEAD(&gsm->tx_list); 2067 } 2068 EXPORT_SYMBOL_GPL(gsm_cleanup_mux); 2069 2070 /** 2071 * gsm_activate_mux - generic GSM setup 2072 * @gsm: our mux 2073 * 2074 * Set up the bits of the mux which are the same for all framing 2075 * protocols. Add the mux to the mux table so it can be opened and 2076 * finally kick off connecting to DLCI 0 on the modem. 2077 */ 2078 2079 int gsm_activate_mux(struct gsm_mux *gsm) 2080 { 2081 struct gsm_dlci *dlci; 2082 int i = 0; 2083 2084 init_timer(&gsm->t2_timer); 2085 gsm->t2_timer.function = gsm_control_retransmit; 2086 gsm->t2_timer.data = (unsigned long)gsm; 2087 init_waitqueue_head(&gsm->event); 2088 spin_lock_init(&gsm->control_lock); 2089 spin_lock_init(&gsm->tx_lock); 2090 2091 if (gsm->encoding == 0) 2092 gsm->receive = gsm0_receive; 2093 else 2094 gsm->receive = gsm1_receive; 2095 gsm->error = gsm_error; 2096 2097 spin_lock(&gsm_mux_lock); 2098 for (i = 0; i < MAX_MUX; i++) { 2099 if (gsm_mux[i] == NULL) { 2100 gsm->num = i; 2101 gsm_mux[i] = gsm; 2102 break; 2103 } 2104 } 2105 spin_unlock(&gsm_mux_lock); 2106 if (i == MAX_MUX) 2107 return -EBUSY; 2108 2109 dlci = gsm_dlci_alloc(gsm, 0); 2110 if (dlci == NULL) 2111 return -ENOMEM; 2112 gsm->dead = 0; /* Tty opens are now permissible */ 2113 return 0; 2114 } 2115 EXPORT_SYMBOL_GPL(gsm_activate_mux); 2116 2117 /** 2118 * gsm_free_mux - free up a mux 2119 * @mux: mux to free 2120 * 2121 * Dispose of allocated resources for a dead mux 2122 */ 2123 void gsm_free_mux(struct gsm_mux *gsm) 2124 { 2125 kfree(gsm->txframe); 2126 kfree(gsm->buf); 2127 kfree(gsm); 2128 } 2129 EXPORT_SYMBOL_GPL(gsm_free_mux); 2130 2131 /** 2132 * gsm_free_muxr - free up a mux 2133 * @mux: mux to free 2134 * 2135 * Dispose of allocated resources for a dead mux 2136 */ 2137 static void gsm_free_muxr(struct kref *ref) 2138 { 2139 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref); 2140 gsm_free_mux(gsm); 2141 } 2142 2143 static inline void mux_get(struct gsm_mux *gsm) 2144 { 2145 kref_get(&gsm->ref); 2146 } 2147 2148 static inline void mux_put(struct gsm_mux *gsm) 2149 { 2150 kref_put(&gsm->ref, gsm_free_muxr); 2151 } 2152 2153 /** 2154 * gsm_alloc_mux - allocate a mux 2155 * 2156 * Creates a new mux ready for activation. 2157 */ 2158 2159 struct gsm_mux *gsm_alloc_mux(void) 2160 { 2161 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL); 2162 if (gsm == NULL) 2163 return NULL; 2164 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL); 2165 if (gsm->buf == NULL) { 2166 kfree(gsm); 2167 return NULL; 2168 } 2169 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL); 2170 if (gsm->txframe == NULL) { 2171 kfree(gsm->buf); 2172 kfree(gsm); 2173 return NULL; 2174 } 2175 spin_lock_init(&gsm->lock); 2176 kref_init(&gsm->ref); 2177 INIT_LIST_HEAD(&gsm->tx_list); 2178 2179 gsm->t1 = T1; 2180 gsm->t2 = T2; 2181 gsm->n2 = N2; 2182 gsm->ftype = UIH; 2183 gsm->adaption = 1; 2184 gsm->encoding = 1; 2185 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */ 2186 gsm->mtu = 64; 2187 gsm->dead = 1; /* Avoid early tty opens */ 2188 2189 return gsm; 2190 } 2191 EXPORT_SYMBOL_GPL(gsm_alloc_mux); 2192 2193 /** 2194 * gsmld_output - write to link 2195 * @gsm: our mux 2196 * @data: bytes to output 2197 * @len: size 2198 * 2199 * Write a block of data from the GSM mux to the data channel. This 2200 * will eventually be serialized from above but at the moment isn't. 2201 */ 2202 2203 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len) 2204 { 2205 if (tty_write_room(gsm->tty) < len) { 2206 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags); 2207 return -ENOSPC; 2208 } 2209 if (debug & 4) 2210 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET, 2211 data, len); 2212 gsm->tty->ops->write(gsm->tty, data, len); 2213 return len; 2214 } 2215 2216 /** 2217 * gsmld_attach_gsm - mode set up 2218 * @tty: our tty structure 2219 * @gsm: our mux 2220 * 2221 * Set up the MUX for basic mode and commence connecting to the 2222 * modem. Currently called from the line discipline set up but 2223 * will need moving to an ioctl path. 2224 */ 2225 2226 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 2227 { 2228 int ret, i; 2229 int base = gsm->num << 6; /* Base for this MUX */ 2230 2231 gsm->tty = tty_kref_get(tty); 2232 gsm->output = gsmld_output; 2233 ret = gsm_activate_mux(gsm); 2234 if (ret != 0) 2235 tty_kref_put(gsm->tty); 2236 else { 2237 /* Don't register device 0 - this is the control channel and not 2238 a usable tty interface */ 2239 for (i = 1; i < NUM_DLCI; i++) 2240 tty_register_device(gsm_tty_driver, base + i, NULL); 2241 } 2242 return ret; 2243 } 2244 2245 2246 /** 2247 * gsmld_detach_gsm - stop doing 0710 mux 2248 * @tty: tty attached to the mux 2249 * @gsm: mux 2250 * 2251 * Shutdown and then clean up the resources used by the line discipline 2252 */ 2253 2254 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 2255 { 2256 int i; 2257 int base = gsm->num << 6; /* Base for this MUX */ 2258 2259 WARN_ON(tty != gsm->tty); 2260 for (i = 1; i < NUM_DLCI; i++) 2261 tty_unregister_device(gsm_tty_driver, base + i); 2262 gsm_cleanup_mux(gsm); 2263 tty_kref_put(gsm->tty); 2264 gsm->tty = NULL; 2265 } 2266 2267 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, 2268 char *fp, int count) 2269 { 2270 struct gsm_mux *gsm = tty->disc_data; 2271 const unsigned char *dp; 2272 char *f; 2273 int i; 2274 char buf[64]; 2275 char flags; 2276 2277 if (debug & 4) 2278 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET, 2279 cp, count); 2280 2281 for (i = count, dp = cp, f = fp; i; i--, dp++) { 2282 flags = *f++; 2283 switch (flags) { 2284 case TTY_NORMAL: 2285 gsm->receive(gsm, *dp); 2286 break; 2287 case TTY_OVERRUN: 2288 case TTY_BREAK: 2289 case TTY_PARITY: 2290 case TTY_FRAME: 2291 gsm->error(gsm, *dp, flags); 2292 break; 2293 default: 2294 WARN_ONCE(1, "%s: unknown flag %d\n", 2295 tty_name(tty, buf), flags); 2296 break; 2297 } 2298 } 2299 /* FASYNC if needed ? */ 2300 /* If clogged call tty_throttle(tty); */ 2301 } 2302 2303 /** 2304 * gsmld_chars_in_buffer - report available bytes 2305 * @tty: tty device 2306 * 2307 * Report the number of characters buffered to be delivered to user 2308 * at this instant in time. 2309 * 2310 * Locking: gsm lock 2311 */ 2312 2313 static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty) 2314 { 2315 return 0; 2316 } 2317 2318 /** 2319 * gsmld_flush_buffer - clean input queue 2320 * @tty: terminal device 2321 * 2322 * Flush the input buffer. Called when the line discipline is 2323 * being closed, when the tty layer wants the buffer flushed (eg 2324 * at hangup). 2325 */ 2326 2327 static void gsmld_flush_buffer(struct tty_struct *tty) 2328 { 2329 } 2330 2331 /** 2332 * gsmld_close - close the ldisc for this tty 2333 * @tty: device 2334 * 2335 * Called from the terminal layer when this line discipline is 2336 * being shut down, either because of a close or becsuse of a 2337 * discipline change. The function will not be called while other 2338 * ldisc methods are in progress. 2339 */ 2340 2341 static void gsmld_close(struct tty_struct *tty) 2342 { 2343 struct gsm_mux *gsm = tty->disc_data; 2344 2345 gsmld_detach_gsm(tty, gsm); 2346 2347 gsmld_flush_buffer(tty); 2348 /* Do other clean up here */ 2349 mux_put(gsm); 2350 } 2351 2352 /** 2353 * gsmld_open - open an ldisc 2354 * @tty: terminal to open 2355 * 2356 * Called when this line discipline is being attached to the 2357 * terminal device. Can sleep. Called serialized so that no 2358 * other events will occur in parallel. No further open will occur 2359 * until a close. 2360 */ 2361 2362 static int gsmld_open(struct tty_struct *tty) 2363 { 2364 struct gsm_mux *gsm; 2365 2366 if (tty->ops->write == NULL) 2367 return -EINVAL; 2368 2369 /* Attach our ldisc data */ 2370 gsm = gsm_alloc_mux(); 2371 if (gsm == NULL) 2372 return -ENOMEM; 2373 2374 tty->disc_data = gsm; 2375 tty->receive_room = 65536; 2376 2377 /* Attach the initial passive connection */ 2378 gsm->encoding = 1; 2379 return gsmld_attach_gsm(tty, gsm); 2380 } 2381 2382 /** 2383 * gsmld_write_wakeup - asynchronous I/O notifier 2384 * @tty: tty device 2385 * 2386 * Required for the ptys, serial driver etc. since processes 2387 * that attach themselves to the master and rely on ASYNC 2388 * IO must be woken up 2389 */ 2390 2391 static void gsmld_write_wakeup(struct tty_struct *tty) 2392 { 2393 struct gsm_mux *gsm = tty->disc_data; 2394 unsigned long flags; 2395 2396 /* Queue poll */ 2397 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 2398 spin_lock_irqsave(&gsm->tx_lock, flags); 2399 gsm_data_kick(gsm); 2400 if (gsm->tx_bytes < TX_THRESH_LO) { 2401 gsm_dlci_data_sweep(gsm); 2402 } 2403 spin_unlock_irqrestore(&gsm->tx_lock, flags); 2404 } 2405 2406 /** 2407 * gsmld_read - read function for tty 2408 * @tty: tty device 2409 * @file: file object 2410 * @buf: userspace buffer pointer 2411 * @nr: size of I/O 2412 * 2413 * Perform reads for the line discipline. We are guaranteed that the 2414 * line discipline will not be closed under us but we may get multiple 2415 * parallel readers and must handle this ourselves. We may also get 2416 * a hangup. Always called in user context, may sleep. 2417 * 2418 * This code must be sure never to sleep through a hangup. 2419 */ 2420 2421 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, 2422 unsigned char __user *buf, size_t nr) 2423 { 2424 return -EOPNOTSUPP; 2425 } 2426 2427 /** 2428 * gsmld_write - write function for tty 2429 * @tty: tty device 2430 * @file: file object 2431 * @buf: userspace buffer pointer 2432 * @nr: size of I/O 2433 * 2434 * Called when the owner of the device wants to send a frame 2435 * itself (or some other control data). The data is transferred 2436 * as-is and must be properly framed and checksummed as appropriate 2437 * by userspace. Frames are either sent whole or not at all as this 2438 * avoids pain user side. 2439 */ 2440 2441 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file, 2442 const unsigned char *buf, size_t nr) 2443 { 2444 int space = tty_write_room(tty); 2445 if (space >= nr) 2446 return tty->ops->write(tty, buf, nr); 2447 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 2448 return -ENOBUFS; 2449 } 2450 2451 /** 2452 * gsmld_poll - poll method for N_GSM0710 2453 * @tty: terminal device 2454 * @file: file accessing it 2455 * @wait: poll table 2456 * 2457 * Called when the line discipline is asked to poll() for data or 2458 * for special events. This code is not serialized with respect to 2459 * other events save open/close. 2460 * 2461 * This code must be sure never to sleep through a hangup. 2462 * Called without the kernel lock held - fine 2463 */ 2464 2465 static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file, 2466 poll_table *wait) 2467 { 2468 unsigned int mask = 0; 2469 struct gsm_mux *gsm = tty->disc_data; 2470 2471 poll_wait(file, &tty->read_wait, wait); 2472 poll_wait(file, &tty->write_wait, wait); 2473 if (tty_hung_up_p(file)) 2474 mask |= POLLHUP; 2475 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0) 2476 mask |= POLLOUT | POLLWRNORM; 2477 if (gsm->dead) 2478 mask |= POLLHUP; 2479 return mask; 2480 } 2481 2482 static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm, 2483 struct gsm_config *c) 2484 { 2485 int need_close = 0; 2486 int need_restart = 0; 2487 2488 /* Stuff we don't support yet - UI or I frame transport, windowing */ 2489 if ((c->adaption != 1 && c->adaption != 2) || c->k) 2490 return -EOPNOTSUPP; 2491 /* Check the MRU/MTU range looks sane */ 2492 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8) 2493 return -EINVAL; 2494 if (c->n2 < 3) 2495 return -EINVAL; 2496 if (c->encapsulation > 1) /* Basic, advanced, no I */ 2497 return -EINVAL; 2498 if (c->initiator > 1) 2499 return -EINVAL; 2500 if (c->i == 0 || c->i > 2) /* UIH and UI only */ 2501 return -EINVAL; 2502 /* 2503 * See what is needed for reconfiguration 2504 */ 2505 2506 /* Timing fields */ 2507 if (c->t1 != 0 && c->t1 != gsm->t1) 2508 need_restart = 1; 2509 if (c->t2 != 0 && c->t2 != gsm->t2) 2510 need_restart = 1; 2511 if (c->encapsulation != gsm->encoding) 2512 need_restart = 1; 2513 if (c->adaption != gsm->adaption) 2514 need_restart = 1; 2515 /* Requires care */ 2516 if (c->initiator != gsm->initiator) 2517 need_close = 1; 2518 if (c->mru != gsm->mru) 2519 need_restart = 1; 2520 if (c->mtu != gsm->mtu) 2521 need_restart = 1; 2522 2523 /* 2524 * Close down what is needed, restart and initiate the new 2525 * configuration 2526 */ 2527 2528 if (need_close || need_restart) { 2529 gsm_dlci_begin_close(gsm->dlci[0]); 2530 /* This will timeout if the link is down due to N2 expiring */ 2531 wait_event_interruptible(gsm->event, 2532 gsm->dlci[0]->state == DLCI_CLOSED); 2533 if (signal_pending(current)) 2534 return -EINTR; 2535 } 2536 if (need_restart) 2537 gsm_cleanup_mux(gsm); 2538 2539 gsm->initiator = c->initiator; 2540 gsm->mru = c->mru; 2541 gsm->mtu = c->mtu; 2542 gsm->encoding = c->encapsulation; 2543 gsm->adaption = c->adaption; 2544 gsm->n2 = c->n2; 2545 2546 if (c->i == 1) 2547 gsm->ftype = UIH; 2548 else if (c->i == 2) 2549 gsm->ftype = UI; 2550 2551 if (c->t1) 2552 gsm->t1 = c->t1; 2553 if (c->t2) 2554 gsm->t2 = c->t2; 2555 2556 /* FIXME: We need to separate activation/deactivation from adding 2557 and removing from the mux array */ 2558 if (need_restart) 2559 gsm_activate_mux(gsm); 2560 if (gsm->initiator && need_close) 2561 gsm_dlci_begin_open(gsm->dlci[0]); 2562 return 0; 2563 } 2564 2565 static int gsmld_ioctl(struct tty_struct *tty, struct file *file, 2566 unsigned int cmd, unsigned long arg) 2567 { 2568 struct gsm_config c; 2569 struct gsm_mux *gsm = tty->disc_data; 2570 2571 switch (cmd) { 2572 case GSMIOC_GETCONF: 2573 memset(&c, 0, sizeof(c)); 2574 c.adaption = gsm->adaption; 2575 c.encapsulation = gsm->encoding; 2576 c.initiator = gsm->initiator; 2577 c.t1 = gsm->t1; 2578 c.t2 = gsm->t2; 2579 c.t3 = 0; /* Not supported */ 2580 c.n2 = gsm->n2; 2581 if (gsm->ftype == UIH) 2582 c.i = 1; 2583 else 2584 c.i = 2; 2585 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i); 2586 c.mru = gsm->mru; 2587 c.mtu = gsm->mtu; 2588 c.k = 0; 2589 if (copy_to_user((void *)arg, &c, sizeof(c))) 2590 return -EFAULT; 2591 return 0; 2592 case GSMIOC_SETCONF: 2593 if (copy_from_user(&c, (void *)arg, sizeof(c))) 2594 return -EFAULT; 2595 return gsmld_config(tty, gsm, &c); 2596 default: 2597 return n_tty_ioctl_helper(tty, file, cmd, arg); 2598 } 2599 } 2600 2601 /* 2602 * Network interface 2603 * 2604 */ 2605 2606 static int gsm_mux_net_open(struct net_device *net) 2607 { 2608 pr_debug("%s called\n", __func__); 2609 netif_start_queue(net); 2610 return 0; 2611 } 2612 2613 static int gsm_mux_net_close(struct net_device *net) 2614 { 2615 netif_stop_queue(net); 2616 return 0; 2617 } 2618 2619 static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net) 2620 { 2621 return &((struct gsm_mux_net *)netdev_priv(net))->stats; 2622 } 2623 static void dlci_net_free(struct gsm_dlci *dlci) 2624 { 2625 if (!dlci->net) { 2626 WARN_ON(1); 2627 return; 2628 } 2629 dlci->adaption = dlci->prev_adaption; 2630 dlci->data = dlci->prev_data; 2631 free_netdev(dlci->net); 2632 dlci->net = NULL; 2633 } 2634 static void net_free(struct kref *ref) 2635 { 2636 struct gsm_mux_net *mux_net; 2637 struct gsm_dlci *dlci; 2638 2639 mux_net = container_of(ref, struct gsm_mux_net, ref); 2640 dlci = mux_net->dlci; 2641 2642 if (dlci->net) { 2643 unregister_netdev(dlci->net); 2644 dlci_net_free(dlci); 2645 } 2646 } 2647 2648 static inline void muxnet_get(struct gsm_mux_net *mux_net) 2649 { 2650 kref_get(&mux_net->ref); 2651 } 2652 2653 static inline void muxnet_put(struct gsm_mux_net *mux_net) 2654 { 2655 kref_put(&mux_net->ref, net_free); 2656 } 2657 2658 static int gsm_mux_net_start_xmit(struct sk_buff *skb, 2659 struct net_device *net) 2660 { 2661 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net); 2662 struct gsm_dlci *dlci = mux_net->dlci; 2663 muxnet_get(mux_net); 2664 2665 skb_queue_head(&dlci->skb_list, skb); 2666 STATS(net).tx_packets++; 2667 STATS(net).tx_bytes += skb->len; 2668 gsm_dlci_data_kick(dlci); 2669 /* And tell the kernel when the last transmit started. */ 2670 net->trans_start = jiffies; 2671 muxnet_put(mux_net); 2672 return NETDEV_TX_OK; 2673 } 2674 2675 /* called when a packet did not ack after watchdogtimeout */ 2676 static void gsm_mux_net_tx_timeout(struct net_device *net) 2677 { 2678 /* Tell syslog we are hosed. */ 2679 dev_dbg(&net->dev, "Tx timed out.\n"); 2680 2681 /* Update statistics */ 2682 STATS(net).tx_errors++; 2683 } 2684 2685 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci, 2686 unsigned char *in_buf, int size) 2687 { 2688 struct net_device *net = dlci->net; 2689 struct sk_buff *skb; 2690 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net); 2691 muxnet_get(mux_net); 2692 2693 /* Allocate an sk_buff */ 2694 skb = dev_alloc_skb(size + NET_IP_ALIGN); 2695 if (!skb) { 2696 /* We got no receive buffer. */ 2697 STATS(net).rx_dropped++; 2698 muxnet_put(mux_net); 2699 return; 2700 } 2701 skb_reserve(skb, NET_IP_ALIGN); 2702 memcpy(skb_put(skb, size), in_buf, size); 2703 2704 skb->dev = net; 2705 skb->protocol = __constant_htons(ETH_P_IP); 2706 2707 /* Ship it off to the kernel */ 2708 netif_rx(skb); 2709 2710 /* update out statistics */ 2711 STATS(net).rx_packets++; 2712 STATS(net).rx_bytes += size; 2713 muxnet_put(mux_net); 2714 return; 2715 } 2716 2717 int gsm_change_mtu(struct net_device *net, int new_mtu) 2718 { 2719 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net); 2720 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu)) 2721 return -EINVAL; 2722 net->mtu = new_mtu; 2723 return 0; 2724 } 2725 2726 static void gsm_mux_net_init(struct net_device *net) 2727 { 2728 static const struct net_device_ops gsm_netdev_ops = { 2729 .ndo_open = gsm_mux_net_open, 2730 .ndo_stop = gsm_mux_net_close, 2731 .ndo_start_xmit = gsm_mux_net_start_xmit, 2732 .ndo_tx_timeout = gsm_mux_net_tx_timeout, 2733 .ndo_get_stats = gsm_mux_net_get_stats, 2734 .ndo_change_mtu = gsm_change_mtu, 2735 }; 2736 2737 net->netdev_ops = &gsm_netdev_ops; 2738 2739 /* fill in the other fields */ 2740 net->watchdog_timeo = GSM_NET_TX_TIMEOUT; 2741 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 2742 net->type = ARPHRD_NONE; 2743 net->tx_queue_len = 10; 2744 } 2745 2746 2747 /* caller holds the dlci mutex */ 2748 static void gsm_destroy_network(struct gsm_dlci *dlci) 2749 { 2750 struct gsm_mux_net *mux_net; 2751 2752 pr_debug("destroy network interface"); 2753 if (!dlci->net) 2754 return; 2755 mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net); 2756 muxnet_put(mux_net); 2757 } 2758 2759 2760 /* caller holds the dlci mutex */ 2761 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc) 2762 { 2763 char *netname; 2764 int retval = 0; 2765 struct net_device *net; 2766 struct gsm_mux_net *mux_net; 2767 2768 if (!capable(CAP_NET_ADMIN)) 2769 return -EPERM; 2770 2771 /* Already in a non tty mode */ 2772 if (dlci->adaption > 2) 2773 return -EBUSY; 2774 2775 if (nc->protocol != htons(ETH_P_IP)) 2776 return -EPROTONOSUPPORT; 2777 2778 if (nc->adaption != 3 && nc->adaption != 4) 2779 return -EPROTONOSUPPORT; 2780 2781 pr_debug("create network interface"); 2782 2783 netname = "gsm%d"; 2784 if (nc->if_name[0] != '\0') 2785 netname = nc->if_name; 2786 net = alloc_netdev(sizeof(struct gsm_mux_net), 2787 netname, 2788 gsm_mux_net_init); 2789 if (!net) { 2790 pr_err("alloc_netdev failed"); 2791 return -ENOMEM; 2792 } 2793 net->mtu = dlci->gsm->mtu; 2794 mux_net = (struct gsm_mux_net *)netdev_priv(net); 2795 mux_net->dlci = dlci; 2796 kref_init(&mux_net->ref); 2797 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */ 2798 2799 /* reconfigure dlci for network */ 2800 dlci->prev_adaption = dlci->adaption; 2801 dlci->prev_data = dlci->data; 2802 dlci->adaption = nc->adaption; 2803 dlci->data = gsm_mux_rx_netchar; 2804 dlci->net = net; 2805 2806 pr_debug("register netdev"); 2807 retval = register_netdev(net); 2808 if (retval) { 2809 pr_err("network register fail %d\n", retval); 2810 dlci_net_free(dlci); 2811 return retval; 2812 } 2813 return net->ifindex; /* return network index */ 2814 } 2815 2816 /* Line discipline for real tty */ 2817 struct tty_ldisc_ops tty_ldisc_packet = { 2818 .owner = THIS_MODULE, 2819 .magic = TTY_LDISC_MAGIC, 2820 .name = "n_gsm", 2821 .open = gsmld_open, 2822 .close = gsmld_close, 2823 .flush_buffer = gsmld_flush_buffer, 2824 .chars_in_buffer = gsmld_chars_in_buffer, 2825 .read = gsmld_read, 2826 .write = gsmld_write, 2827 .ioctl = gsmld_ioctl, 2828 .poll = gsmld_poll, 2829 .receive_buf = gsmld_receive_buf, 2830 .write_wakeup = gsmld_write_wakeup 2831 }; 2832 2833 /* 2834 * Virtual tty side 2835 */ 2836 2837 #define TX_SIZE 512 2838 2839 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) 2840 { 2841 u8 modembits[5]; 2842 struct gsm_control *ctrl; 2843 int len = 2; 2844 2845 if (brk) 2846 len++; 2847 2848 modembits[0] = len << 1 | EA; /* Data bytes */ 2849 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */ 2850 modembits[2] = gsm_encode_modem(dlci) << 1 | EA; 2851 if (brk) 2852 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */ 2853 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1); 2854 if (ctrl == NULL) 2855 return -ENOMEM; 2856 return gsm_control_wait(dlci->gsm, ctrl); 2857 } 2858 2859 static int gsm_carrier_raised(struct tty_port *port) 2860 { 2861 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2862 /* Not yet open so no carrier info */ 2863 if (dlci->state != DLCI_OPEN) 2864 return 0; 2865 if (debug & 2) 2866 return 1; 2867 return dlci->modem_rx & TIOCM_CD; 2868 } 2869 2870 static void gsm_dtr_rts(struct tty_port *port, int onoff) 2871 { 2872 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2873 unsigned int modem_tx = dlci->modem_tx; 2874 if (onoff) 2875 modem_tx |= TIOCM_DTR | TIOCM_RTS; 2876 else 2877 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); 2878 if (modem_tx != dlci->modem_tx) { 2879 dlci->modem_tx = modem_tx; 2880 gsmtty_modem_update(dlci, 0); 2881 } 2882 } 2883 2884 static const struct tty_port_operations gsm_port_ops = { 2885 .carrier_raised = gsm_carrier_raised, 2886 .dtr_rts = gsm_dtr_rts, 2887 .destruct = gsm_dlci_free, 2888 }; 2889 2890 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty) 2891 { 2892 struct gsm_mux *gsm; 2893 struct gsm_dlci *dlci; 2894 unsigned int line = tty->index; 2895 unsigned int mux = line >> 6; 2896 bool alloc = false; 2897 int ret; 2898 2899 line = line & 0x3F; 2900 2901 if (mux >= MAX_MUX) 2902 return -ENXIO; 2903 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */ 2904 if (gsm_mux[mux] == NULL) 2905 return -EUNATCH; 2906 if (line == 0 || line > 61) /* 62/63 reserved */ 2907 return -ECHRNG; 2908 gsm = gsm_mux[mux]; 2909 if (gsm->dead) 2910 return -EL2HLT; 2911 /* If DLCI 0 is not yet fully open return an error. This is ok from a locking 2912 perspective as we don't have to worry about this if DLCI0 is lost */ 2913 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) 2914 return -EL2NSYNC; 2915 dlci = gsm->dlci[line]; 2916 if (dlci == NULL) { 2917 alloc = true; 2918 dlci = gsm_dlci_alloc(gsm, line); 2919 } 2920 if (dlci == NULL) 2921 return -ENOMEM; 2922 ret = tty_port_install(&dlci->port, driver, tty); 2923 if (ret) { 2924 if (alloc) 2925 dlci_put(dlci); 2926 return ret; 2927 } 2928 2929 tty->driver_data = dlci; 2930 2931 return 0; 2932 } 2933 2934 static int gsmtty_open(struct tty_struct *tty, struct file *filp) 2935 { 2936 struct gsm_dlci *dlci = tty->driver_data; 2937 struct tty_port *port = &dlci->port; 2938 2939 port->count++; 2940 dlci_get(dlci); 2941 dlci_get(dlci->gsm->dlci[0]); 2942 mux_get(dlci->gsm); 2943 tty_port_tty_set(port, tty); 2944 2945 dlci->modem_rx = 0; 2946 /* We could in theory open and close before we wait - eg if we get 2947 a DM straight back. This is ok as that will have caused a hangup */ 2948 set_bit(ASYNCB_INITIALIZED, &port->flags); 2949 /* Start sending off SABM messages */ 2950 gsm_dlci_begin_open(dlci); 2951 /* And wait for virtual carrier */ 2952 return tty_port_block_til_ready(port, tty, filp); 2953 } 2954 2955 static void gsmtty_close(struct tty_struct *tty, struct file *filp) 2956 { 2957 struct gsm_dlci *dlci = tty->driver_data; 2958 struct gsm_mux *gsm; 2959 2960 if (dlci == NULL) 2961 return; 2962 if (dlci->state == DLCI_CLOSED) 2963 return; 2964 mutex_lock(&dlci->mutex); 2965 gsm_destroy_network(dlci); 2966 mutex_unlock(&dlci->mutex); 2967 gsm = dlci->gsm; 2968 if (tty_port_close_start(&dlci->port, tty, filp) == 0) 2969 goto out; 2970 gsm_dlci_begin_close(dlci); 2971 tty_port_close_end(&dlci->port, tty); 2972 tty_port_tty_set(&dlci->port, NULL); 2973 out: 2974 dlci_put(dlci); 2975 dlci_put(gsm->dlci[0]); 2976 mux_put(gsm); 2977 } 2978 2979 static void gsmtty_hangup(struct tty_struct *tty) 2980 { 2981 struct gsm_dlci *dlci = tty->driver_data; 2982 if (dlci->state == DLCI_CLOSED) 2983 return; 2984 tty_port_hangup(&dlci->port); 2985 gsm_dlci_begin_close(dlci); 2986 } 2987 2988 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf, 2989 int len) 2990 { 2991 int sent; 2992 struct gsm_dlci *dlci = tty->driver_data; 2993 if (dlci->state == DLCI_CLOSED) 2994 return -EINVAL; 2995 /* Stuff the bytes into the fifo queue */ 2996 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock); 2997 /* Need to kick the channel */ 2998 gsm_dlci_data_kick(dlci); 2999 return sent; 3000 } 3001 3002 static int gsmtty_write_room(struct tty_struct *tty) 3003 { 3004 struct gsm_dlci *dlci = tty->driver_data; 3005 if (dlci->state == DLCI_CLOSED) 3006 return -EINVAL; 3007 return TX_SIZE - kfifo_len(dlci->fifo); 3008 } 3009 3010 static int gsmtty_chars_in_buffer(struct tty_struct *tty) 3011 { 3012 struct gsm_dlci *dlci = tty->driver_data; 3013 if (dlci->state == DLCI_CLOSED) 3014 return -EINVAL; 3015 return kfifo_len(dlci->fifo); 3016 } 3017 3018 static void gsmtty_flush_buffer(struct tty_struct *tty) 3019 { 3020 struct gsm_dlci *dlci = tty->driver_data; 3021 if (dlci->state == DLCI_CLOSED) 3022 return; 3023 /* Caution needed: If we implement reliable transport classes 3024 then the data being transmitted can't simply be junked once 3025 it has first hit the stack. Until then we can just blow it 3026 away */ 3027 kfifo_reset(dlci->fifo); 3028 /* Need to unhook this DLCI from the transmit queue logic */ 3029 } 3030 3031 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout) 3032 { 3033 /* The FIFO handles the queue so the kernel will do the right 3034 thing waiting on chars_in_buffer before calling us. No work 3035 to do here */ 3036 } 3037 3038 static int gsmtty_tiocmget(struct tty_struct *tty) 3039 { 3040 struct gsm_dlci *dlci = tty->driver_data; 3041 if (dlci->state == DLCI_CLOSED) 3042 return -EINVAL; 3043 return dlci->modem_rx; 3044 } 3045 3046 static int gsmtty_tiocmset(struct tty_struct *tty, 3047 unsigned int set, unsigned int clear) 3048 { 3049 struct gsm_dlci *dlci = tty->driver_data; 3050 unsigned int modem_tx = dlci->modem_tx; 3051 3052 if (dlci->state == DLCI_CLOSED) 3053 return -EINVAL; 3054 modem_tx &= ~clear; 3055 modem_tx |= set; 3056 3057 if (modem_tx != dlci->modem_tx) { 3058 dlci->modem_tx = modem_tx; 3059 return gsmtty_modem_update(dlci, 0); 3060 } 3061 return 0; 3062 } 3063 3064 3065 static int gsmtty_ioctl(struct tty_struct *tty, 3066 unsigned int cmd, unsigned long arg) 3067 { 3068 struct gsm_dlci *dlci = tty->driver_data; 3069 struct gsm_netconfig nc; 3070 int index; 3071 3072 if (dlci->state == DLCI_CLOSED) 3073 return -EINVAL; 3074 switch (cmd) { 3075 case GSMIOC_ENABLE_NET: 3076 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc))) 3077 return -EFAULT; 3078 nc.if_name[IFNAMSIZ-1] = '\0'; 3079 /* return net interface index or error code */ 3080 mutex_lock(&dlci->mutex); 3081 index = gsm_create_network(dlci, &nc); 3082 mutex_unlock(&dlci->mutex); 3083 if (copy_to_user((void __user *)arg, &nc, sizeof(nc))) 3084 return -EFAULT; 3085 return index; 3086 case GSMIOC_DISABLE_NET: 3087 if (!capable(CAP_NET_ADMIN)) 3088 return -EPERM; 3089 mutex_lock(&dlci->mutex); 3090 gsm_destroy_network(dlci); 3091 mutex_unlock(&dlci->mutex); 3092 return 0; 3093 default: 3094 return -ENOIOCTLCMD; 3095 } 3096 } 3097 3098 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old) 3099 { 3100 struct gsm_dlci *dlci = tty->driver_data; 3101 if (dlci->state == DLCI_CLOSED) 3102 return; 3103 /* For the moment its fixed. In actual fact the speed information 3104 for the virtual channel can be propogated in both directions by 3105 the RPN control message. This however rapidly gets nasty as we 3106 then have to remap modem signals each way according to whether 3107 our virtual cable is null modem etc .. */ 3108 tty_termios_copy_hw(&tty->termios, old); 3109 } 3110 3111 static void gsmtty_throttle(struct tty_struct *tty) 3112 { 3113 struct gsm_dlci *dlci = tty->driver_data; 3114 if (dlci->state == DLCI_CLOSED) 3115 return; 3116 if (tty->termios.c_cflag & CRTSCTS) 3117 dlci->modem_tx &= ~TIOCM_DTR; 3118 dlci->throttled = 1; 3119 /* Send an MSC with DTR cleared */ 3120 gsmtty_modem_update(dlci, 0); 3121 } 3122 3123 static void gsmtty_unthrottle(struct tty_struct *tty) 3124 { 3125 struct gsm_dlci *dlci = tty->driver_data; 3126 if (dlci->state == DLCI_CLOSED) 3127 return; 3128 if (tty->termios.c_cflag & CRTSCTS) 3129 dlci->modem_tx |= TIOCM_DTR; 3130 dlci->throttled = 0; 3131 /* Send an MSC with DTR set */ 3132 gsmtty_modem_update(dlci, 0); 3133 } 3134 3135 static int gsmtty_break_ctl(struct tty_struct *tty, int state) 3136 { 3137 struct gsm_dlci *dlci = tty->driver_data; 3138 int encode = 0; /* Off */ 3139 if (dlci->state == DLCI_CLOSED) 3140 return -EINVAL; 3141 3142 if (state == -1) /* "On indefinitely" - we can't encode this 3143 properly */ 3144 encode = 0x0F; 3145 else if (state > 0) { 3146 encode = state / 200; /* mS to encoding */ 3147 if (encode > 0x0F) 3148 encode = 0x0F; /* Best effort */ 3149 } 3150 return gsmtty_modem_update(dlci, encode); 3151 } 3152 3153 3154 /* Virtual ttys for the demux */ 3155 static const struct tty_operations gsmtty_ops = { 3156 .install = gsmtty_install, 3157 .open = gsmtty_open, 3158 .close = gsmtty_close, 3159 .write = gsmtty_write, 3160 .write_room = gsmtty_write_room, 3161 .chars_in_buffer = gsmtty_chars_in_buffer, 3162 .flush_buffer = gsmtty_flush_buffer, 3163 .ioctl = gsmtty_ioctl, 3164 .throttle = gsmtty_throttle, 3165 .unthrottle = gsmtty_unthrottle, 3166 .set_termios = gsmtty_set_termios, 3167 .hangup = gsmtty_hangup, 3168 .wait_until_sent = gsmtty_wait_until_sent, 3169 .tiocmget = gsmtty_tiocmget, 3170 .tiocmset = gsmtty_tiocmset, 3171 .break_ctl = gsmtty_break_ctl, 3172 }; 3173 3174 3175 3176 static int __init gsm_init(void) 3177 { 3178 /* Fill in our line protocol discipline, and register it */ 3179 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet); 3180 if (status != 0) { 3181 pr_err("n_gsm: can't register line discipline (err = %d)\n", 3182 status); 3183 return status; 3184 } 3185 3186 gsm_tty_driver = alloc_tty_driver(256); 3187 if (!gsm_tty_driver) { 3188 tty_unregister_ldisc(N_GSM0710); 3189 pr_err("gsm_init: tty allocation failed.\n"); 3190 return -EINVAL; 3191 } 3192 gsm_tty_driver->driver_name = "gsmtty"; 3193 gsm_tty_driver->name = "gsmtty"; 3194 gsm_tty_driver->major = 0; /* Dynamic */ 3195 gsm_tty_driver->minor_start = 0; 3196 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; 3197 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL; 3198 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV 3199 | TTY_DRIVER_HARDWARE_BREAK; 3200 gsm_tty_driver->init_termios = tty_std_termios; 3201 /* Fixme */ 3202 gsm_tty_driver->init_termios.c_lflag &= ~ECHO; 3203 tty_set_operations(gsm_tty_driver, &gsmtty_ops); 3204 3205 spin_lock_init(&gsm_mux_lock); 3206 3207 if (tty_register_driver(gsm_tty_driver)) { 3208 put_tty_driver(gsm_tty_driver); 3209 tty_unregister_ldisc(N_GSM0710); 3210 pr_err("gsm_init: tty registration failed.\n"); 3211 return -EBUSY; 3212 } 3213 pr_debug("gsm_init: loaded as %d,%d.\n", 3214 gsm_tty_driver->major, gsm_tty_driver->minor_start); 3215 return 0; 3216 } 3217 3218 static void __exit gsm_exit(void) 3219 { 3220 int status = tty_unregister_ldisc(N_GSM0710); 3221 if (status != 0) 3222 pr_err("n_gsm: can't unregister line discipline (err = %d)\n", 3223 status); 3224 tty_unregister_driver(gsm_tty_driver); 3225 put_tty_driver(gsm_tty_driver); 3226 } 3227 3228 module_init(gsm_init); 3229 module_exit(gsm_exit); 3230 3231 3232 MODULE_LICENSE("GPL"); 3233 MODULE_ALIAS_LDISC(N_GSM0710); 3234