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 #define T1 (HZ/10) 70 #define T2 (HZ/3) 71 #define N2 3 72 73 /* Use long timers for testing at low speed with debug on */ 74 #ifdef DEBUG_TIMING 75 #define T1 HZ 76 #define T2 (2 * HZ) 77 #endif 78 79 /* 80 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte 81 * limits so this is plenty 82 */ 83 #define MAX_MRU 1500 84 #define MAX_MTU 1500 85 #define GSM_NET_TX_TIMEOUT (HZ*10) 86 87 /** 88 * struct gsm_mux_net - network interface 89 * @struct gsm_dlci* dlci 90 * @struct net_device_stats stats; 91 * 92 * Created when net interface is initialized. 93 **/ 94 struct gsm_mux_net { 95 struct kref ref; 96 struct gsm_dlci *dlci; 97 struct net_device_stats stats; 98 }; 99 100 #define STATS(net) (((struct gsm_mux_net *)netdev_priv(net))->stats) 101 102 /* 103 * Each block of data we have queued to go out is in the form of 104 * a gsm_msg which holds everything we need in a link layer independent 105 * format 106 */ 107 108 struct gsm_msg { 109 struct gsm_msg *next; 110 u8 addr; /* DLCI address + flags */ 111 u8 ctrl; /* Control byte + flags */ 112 unsigned int len; /* Length of data block (can be zero) */ 113 unsigned char *data; /* Points into buffer but not at the start */ 114 unsigned char buffer[0]; 115 }; 116 117 /* 118 * Each active data link has a gsm_dlci structure associated which ties 119 * the link layer to an optional tty (if the tty side is open). To avoid 120 * complexity right now these are only ever freed up when the mux is 121 * shut down. 122 * 123 * At the moment we don't free DLCI objects until the mux is torn down 124 * this avoid object life time issues but might be worth review later. 125 */ 126 127 struct gsm_dlci { 128 struct gsm_mux *gsm; 129 int addr; 130 int state; 131 #define DLCI_CLOSED 0 132 #define DLCI_OPENING 1 /* Sending SABM not seen UA */ 133 #define DLCI_OPEN 2 /* SABM/UA complete */ 134 #define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */ 135 struct kref ref; /* freed from port or mux close */ 136 struct mutex mutex; 137 138 /* Link layer */ 139 spinlock_t lock; /* Protects the internal state */ 140 struct timer_list t1; /* Retransmit timer for SABM and UA */ 141 int retries; 142 /* Uplink tty if active */ 143 struct tty_port port; /* The tty bound to this DLCI if there is one */ 144 struct kfifo *fifo; /* Queue fifo for the DLCI */ 145 struct kfifo _fifo; /* For new fifo API porting only */ 146 int adaption; /* Adaption layer in use */ 147 int prev_adaption; 148 u32 modem_rx; /* Our incoming virtual modem lines */ 149 u32 modem_tx; /* Our outgoing modem lines */ 150 int dead; /* Refuse re-open */ 151 /* Flow control */ 152 int throttled; /* Private copy of throttle state */ 153 int constipated; /* Throttle status for outgoing */ 154 /* Packetised I/O */ 155 struct sk_buff *skb; /* Frame being sent */ 156 struct sk_buff_head skb_list; /* Queued frames */ 157 /* Data handling callback */ 158 void (*data)(struct gsm_dlci *dlci, u8 *data, int len); 159 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len); 160 struct net_device *net; /* network interface, if created */ 161 }; 162 163 /* DLCI 0, 62/63 are special or reseved see gsmtty_open */ 164 165 #define NUM_DLCI 64 166 167 /* 168 * DLCI 0 is used to pass control blocks out of band of the data 169 * flow (and with a higher link priority). One command can be outstanding 170 * at a time and we use this structure to manage them. They are created 171 * and destroyed by the user context, and updated by the receive paths 172 * and timers 173 */ 174 175 struct gsm_control { 176 u8 cmd; /* Command we are issuing */ 177 u8 *data; /* Data for the command in case we retransmit */ 178 int len; /* Length of block for retransmission */ 179 int done; /* Done flag */ 180 int error; /* Error if any */ 181 }; 182 183 /* 184 * Each GSM mux we have is represented by this structure. If we are 185 * operating as an ldisc then we use this structure as our ldisc 186 * state. We need to sort out lifetimes and locking with respect 187 * to the gsm mux array. For now we don't free DLCI objects that 188 * have been instantiated until the mux itself is terminated. 189 * 190 * To consider further: tty open versus mux shutdown. 191 */ 192 193 struct gsm_mux { 194 struct tty_struct *tty; /* The tty our ldisc is bound to */ 195 spinlock_t lock; 196 unsigned int num; 197 struct kref ref; 198 199 /* Events on the GSM channel */ 200 wait_queue_head_t event; 201 202 /* Bits for GSM mode decoding */ 203 204 /* Framing Layer */ 205 unsigned char *buf; 206 int state; 207 #define GSM_SEARCH 0 208 #define GSM_START 1 209 #define GSM_ADDRESS 2 210 #define GSM_CONTROL 3 211 #define GSM_LEN 4 212 #define GSM_DATA 5 213 #define GSM_FCS 6 214 #define GSM_OVERRUN 7 215 #define GSM_LEN0 8 216 #define GSM_LEN1 9 217 #define GSM_SSOF 10 218 unsigned int len; 219 unsigned int address; 220 unsigned int count; 221 int escape; 222 int encoding; 223 u8 control; 224 u8 fcs; 225 u8 received_fcs; 226 u8 *txframe; /* TX framing buffer */ 227 228 /* Methods for the receiver side */ 229 void (*receive)(struct gsm_mux *gsm, u8 ch); 230 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag); 231 /* And transmit side */ 232 int (*output)(struct gsm_mux *mux, u8 *data, int len); 233 234 /* Link Layer */ 235 unsigned int mru; 236 unsigned int mtu; 237 int initiator; /* Did we initiate connection */ 238 int dead; /* Has the mux been shut down */ 239 struct gsm_dlci *dlci[NUM_DLCI]; 240 int constipated; /* Asked by remote to shut up */ 241 242 spinlock_t tx_lock; 243 unsigned int tx_bytes; /* TX data outstanding */ 244 #define TX_THRESH_HI 8192 245 #define TX_THRESH_LO 2048 246 struct gsm_msg *tx_head; /* Pending data packets */ 247 struct gsm_msg *tx_tail; 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 & 0xE) >> 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 m->next = NULL; 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 * 675 * FIXME: lock against link layer control transmissions 676 */ 677 678 static void gsm_data_kick(struct gsm_mux *gsm) 679 { 680 struct gsm_msg *msg = gsm->tx_head; 681 int len; 682 int skip_sof = 0; 683 684 /* FIXME: We need to apply this solely to data messages */ 685 if (gsm->constipated) 686 return; 687 688 while (gsm->tx_head != NULL) { 689 msg = gsm->tx_head; 690 if (gsm->encoding != 0) { 691 gsm->txframe[0] = GSM1_SOF; 692 len = gsm_stuff_frame(msg->data, 693 gsm->txframe + 1, msg->len); 694 gsm->txframe[len + 1] = GSM1_SOF; 695 len += 2; 696 } else { 697 gsm->txframe[0] = GSM0_SOF; 698 memcpy(gsm->txframe + 1 , msg->data, msg->len); 699 gsm->txframe[msg->len + 1] = GSM0_SOF; 700 len = msg->len + 2; 701 } 702 703 if (debug & 4) 704 print_hex_dump_bytes("gsm_data_kick: ", 705 DUMP_PREFIX_OFFSET, 706 gsm->txframe, len); 707 708 if (gsm->output(gsm, gsm->txframe + skip_sof, 709 len - skip_sof) < 0) 710 break; 711 /* FIXME: Can eliminate one SOF in many more cases */ 712 gsm->tx_head = msg->next; 713 if (gsm->tx_head == NULL) 714 gsm->tx_tail = NULL; 715 gsm->tx_bytes -= msg->len; 716 kfree(msg); 717 /* For a burst of frames skip the extra SOF within the 718 burst */ 719 skip_sof = 1; 720 } 721 } 722 723 /** 724 * __gsm_data_queue - queue a UI or UIH frame 725 * @dlci: DLCI sending the data 726 * @msg: message queued 727 * 728 * Add data to the transmit queue and try and get stuff moving 729 * out of the mux tty if not already doing so. The Caller must hold 730 * the gsm tx lock. 731 */ 732 733 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) 734 { 735 struct gsm_mux *gsm = dlci->gsm; 736 u8 *dp = msg->data; 737 u8 *fcs = dp + msg->len; 738 739 /* Fill in the header */ 740 if (gsm->encoding == 0) { 741 if (msg->len < 128) 742 *--dp = (msg->len << 1) | EA; 743 else { 744 *--dp = (msg->len >> 7); /* bits 7 - 15 */ 745 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */ 746 } 747 } 748 749 *--dp = msg->ctrl; 750 if (gsm->initiator) 751 *--dp = (msg->addr << 2) | 2 | EA; 752 else 753 *--dp = (msg->addr << 2) | EA; 754 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp); 755 /* Ugly protocol layering violation */ 756 if (msg->ctrl == UI || msg->ctrl == (UI|PF)) 757 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len); 758 *fcs = 0xFF - *fcs; 759 760 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl, 761 msg->data, msg->len); 762 763 /* Move the header back and adjust the length, also allow for the FCS 764 now tacked on the end */ 765 msg->len += (msg->data - dp) + 1; 766 msg->data = dp; 767 768 /* Add to the actual output queue */ 769 if (gsm->tx_tail) 770 gsm->tx_tail->next = msg; 771 else 772 gsm->tx_head = msg; 773 gsm->tx_tail = msg; 774 gsm->tx_bytes += msg->len; 775 gsm_data_kick(gsm); 776 } 777 778 /** 779 * gsm_data_queue - queue a UI or UIH frame 780 * @dlci: DLCI sending the data 781 * @msg: message queued 782 * 783 * Add data to the transmit queue and try and get stuff moving 784 * out of the mux tty if not already doing so. Take the 785 * the gsm tx lock and dlci lock. 786 */ 787 788 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) 789 { 790 unsigned long flags; 791 spin_lock_irqsave(&dlci->gsm->tx_lock, flags); 792 __gsm_data_queue(dlci, msg); 793 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); 794 } 795 796 /** 797 * gsm_dlci_data_output - try and push data out of a DLCI 798 * @gsm: mux 799 * @dlci: the DLCI to pull data from 800 * 801 * Pull data from a DLCI and send it into the transmit queue if there 802 * is data. Keep to the MRU of the mux. This path handles the usual tty 803 * interface which is a byte stream with optional modem data. 804 * 805 * Caller must hold the tx_lock of the mux. 806 */ 807 808 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci) 809 { 810 struct gsm_msg *msg; 811 u8 *dp; 812 int len, total_size, size; 813 int h = dlci->adaption - 1; 814 815 total_size = 0; 816 while(1) { 817 len = kfifo_len(dlci->fifo); 818 if (len == 0) 819 return total_size; 820 821 /* MTU/MRU count only the data bits */ 822 if (len > gsm->mtu) 823 len = gsm->mtu; 824 825 size = len + h; 826 827 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); 828 /* FIXME: need a timer or something to kick this so it can't 829 get stuck with no work outstanding and no buffer free */ 830 if (msg == NULL) 831 return -ENOMEM; 832 dp = msg->data; 833 switch (dlci->adaption) { 834 case 1: /* Unstructured */ 835 break; 836 case 2: /* Unstructed with modem bits. Always one byte as we never 837 send inline break data */ 838 *dp++ = gsm_encode_modem(dlci); 839 break; 840 } 841 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len); 842 __gsm_data_queue(dlci, msg); 843 total_size += size; 844 } 845 /* Bytes of data we used up */ 846 return total_size; 847 } 848 849 /** 850 * gsm_dlci_data_output_framed - try and push data out of a DLCI 851 * @gsm: mux 852 * @dlci: the DLCI to pull data from 853 * 854 * Pull data from a DLCI and send it into the transmit queue if there 855 * is data. Keep to the MRU of the mux. This path handles framed data 856 * queued as skbuffs to the DLCI. 857 * 858 * Caller must hold the tx_lock of the mux. 859 */ 860 861 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, 862 struct gsm_dlci *dlci) 863 { 864 struct gsm_msg *msg; 865 u8 *dp; 866 int len, size; 867 int last = 0, first = 0; 868 int overhead = 0; 869 870 /* One byte per frame is used for B/F flags */ 871 if (dlci->adaption == 4) 872 overhead = 1; 873 874 /* dlci->skb is locked by tx_lock */ 875 if (dlci->skb == NULL) { 876 dlci->skb = skb_dequeue(&dlci->skb_list); 877 if (dlci->skb == NULL) 878 return 0; 879 first = 1; 880 } 881 len = dlci->skb->len + overhead; 882 883 /* MTU/MRU count only the data bits */ 884 if (len > gsm->mtu) { 885 if (dlci->adaption == 3) { 886 /* Over long frame, bin it */ 887 kfree_skb(dlci->skb); 888 dlci->skb = NULL; 889 return 0; 890 } 891 len = gsm->mtu; 892 } else 893 last = 1; 894 895 size = len + overhead; 896 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); 897 898 /* FIXME: need a timer or something to kick this so it can't 899 get stuck with no work outstanding and no buffer free */ 900 if (msg == NULL) 901 return -ENOMEM; 902 dp = msg->data; 903 904 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */ 905 /* Flag byte to carry the start/end info */ 906 *dp++ = last << 7 | first << 6 | 1; /* EA */ 907 len--; 908 } 909 memcpy(dp, dlci->skb->data, len); 910 skb_pull(dlci->skb, len); 911 __gsm_data_queue(dlci, msg); 912 if (last) { 913 kfree_skb(dlci->skb); 914 dlci->skb = NULL; 915 } 916 return size; 917 } 918 919 /** 920 * gsm_dlci_data_sweep - look for data to send 921 * @gsm: the GSM mux 922 * 923 * Sweep the GSM mux channels in priority order looking for ones with 924 * data to send. We could do with optimising this scan a bit. We aim 925 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit 926 * TX_THRESH_LO we get called again 927 * 928 * FIXME: We should round robin between groups and in theory you can 929 * renegotiate DLCI priorities with optional stuff. Needs optimising. 930 */ 931 932 static void gsm_dlci_data_sweep(struct gsm_mux *gsm) 933 { 934 int len; 935 /* Priority ordering: We should do priority with RR of the groups */ 936 int i = 1; 937 938 while (i < NUM_DLCI) { 939 struct gsm_dlci *dlci; 940 941 if (gsm->tx_bytes > TX_THRESH_HI) 942 break; 943 dlci = gsm->dlci[i]; 944 if (dlci == NULL || dlci->constipated) { 945 i++; 946 continue; 947 } 948 if (dlci->adaption < 3 && !dlci->net) 949 len = gsm_dlci_data_output(gsm, dlci); 950 else 951 len = gsm_dlci_data_output_framed(gsm, dlci); 952 if (len < 0) 953 break; 954 /* DLCI empty - try the next */ 955 if (len == 0) 956 i++; 957 } 958 } 959 960 /** 961 * gsm_dlci_data_kick - transmit if possible 962 * @dlci: DLCI to kick 963 * 964 * Transmit data from this DLCI if the queue is empty. We can't rely on 965 * a tty wakeup except when we filled the pipe so we need to fire off 966 * new data ourselves in other cases. 967 */ 968 969 static void gsm_dlci_data_kick(struct gsm_dlci *dlci) 970 { 971 unsigned long flags; 972 973 spin_lock_irqsave(&dlci->gsm->tx_lock, flags); 974 /* If we have nothing running then we need to fire up */ 975 if (dlci->gsm->tx_bytes == 0) { 976 if (dlci->net) 977 gsm_dlci_data_output_framed(dlci->gsm, dlci); 978 else 979 gsm_dlci_data_output(dlci->gsm, dlci); 980 } else if (dlci->gsm->tx_bytes < TX_THRESH_LO) 981 gsm_dlci_data_sweep(dlci->gsm); 982 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); 983 } 984 985 /* 986 * Control message processing 987 */ 988 989 990 /** 991 * gsm_control_reply - send a response frame to a control 992 * @gsm: gsm channel 993 * @cmd: the command to use 994 * @data: data to follow encoded info 995 * @dlen: length of data 996 * 997 * Encode up and queue a UI/UIH frame containing our response. 998 */ 999 1000 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data, 1001 int dlen) 1002 { 1003 struct gsm_msg *msg; 1004 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype); 1005 if (msg == NULL) 1006 return; 1007 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */ 1008 msg->data[1] = (dlen << 1) | EA; 1009 memcpy(msg->data + 2, data, dlen); 1010 gsm_data_queue(gsm->dlci[0], msg); 1011 } 1012 1013 /** 1014 * gsm_process_modem - process received modem status 1015 * @tty: virtual tty bound to the DLCI 1016 * @dlci: DLCI to affect 1017 * @modem: modem bits (full EA) 1018 * 1019 * Used when a modem control message or line state inline in adaption 1020 * layer 2 is processed. Sort out the local modem state and throttles 1021 */ 1022 1023 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci, 1024 u32 modem, int clen) 1025 { 1026 int mlines = 0; 1027 u8 brk = 0; 1028 1029 /* The modem status command can either contain one octet (v.24 signals) 1030 or two octets (v.24 signals + break signals). The length field will 1031 either be 2 or 3 respectively. This is specified in section 1032 5.4.6.3.7 of the 27.010 mux spec. */ 1033 1034 if (clen == 2) 1035 modem = modem & 0x7f; 1036 else { 1037 brk = modem & 0x7f; 1038 modem = (modem >> 7) & 0x7f; 1039 }; 1040 1041 /* Flow control/ready to communicate */ 1042 if (modem & MDM_FC) { 1043 /* Need to throttle our output on this device */ 1044 dlci->constipated = 1; 1045 } 1046 if (modem & MDM_RTC) { 1047 mlines |= TIOCM_DSR | TIOCM_DTR; 1048 dlci->constipated = 0; 1049 gsm_dlci_data_kick(dlci); 1050 } 1051 /* Map modem bits */ 1052 if (modem & MDM_RTR) 1053 mlines |= TIOCM_RTS | TIOCM_CTS; 1054 if (modem & MDM_IC) 1055 mlines |= TIOCM_RI; 1056 if (modem & MDM_DV) 1057 mlines |= TIOCM_CD; 1058 1059 /* Carrier drop -> hangup */ 1060 if (tty) { 1061 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD)) 1062 if (!(tty->termios->c_cflag & CLOCAL)) 1063 tty_hangup(tty); 1064 if (brk & 0x01) 1065 tty_insert_flip_char(tty, 0, TTY_BREAK); 1066 } 1067 dlci->modem_rx = mlines; 1068 } 1069 1070 /** 1071 * gsm_control_modem - modem status received 1072 * @gsm: GSM channel 1073 * @data: data following command 1074 * @clen: command length 1075 * 1076 * We have received a modem status control message. This is used by 1077 * the GSM mux protocol to pass virtual modem line status and optionally 1078 * to indicate break signals. Unpack it, convert to Linux representation 1079 * and if need be stuff a break message down the tty. 1080 */ 1081 1082 static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen) 1083 { 1084 unsigned int addr = 0; 1085 unsigned int modem = 0; 1086 struct gsm_dlci *dlci; 1087 int len = clen; 1088 u8 *dp = data; 1089 struct tty_struct *tty; 1090 1091 while (gsm_read_ea(&addr, *dp++) == 0) { 1092 len--; 1093 if (len == 0) 1094 return; 1095 } 1096 /* Must be at least one byte following the EA */ 1097 len--; 1098 if (len <= 0) 1099 return; 1100 1101 addr >>= 1; 1102 /* Closed port, or invalid ? */ 1103 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) 1104 return; 1105 dlci = gsm->dlci[addr]; 1106 1107 while (gsm_read_ea(&modem, *dp++) == 0) { 1108 len--; 1109 if (len == 0) 1110 return; 1111 } 1112 tty = tty_port_tty_get(&dlci->port); 1113 gsm_process_modem(tty, dlci, modem, clen); 1114 if (tty) { 1115 tty_wakeup(tty); 1116 tty_kref_put(tty); 1117 } 1118 gsm_control_reply(gsm, CMD_MSC, data, clen); 1119 } 1120 1121 /** 1122 * gsm_control_rls - remote line status 1123 * @gsm: GSM channel 1124 * @data: data bytes 1125 * @clen: data length 1126 * 1127 * The modem sends us a two byte message on the control channel whenever 1128 * it wishes to send us an error state from the virtual link. Stuff 1129 * this into the uplink tty if present 1130 */ 1131 1132 static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen) 1133 { 1134 struct tty_struct *tty; 1135 unsigned int addr = 0 ; 1136 u8 bits; 1137 int len = clen; 1138 u8 *dp = data; 1139 1140 while (gsm_read_ea(&addr, *dp++) == 0) { 1141 len--; 1142 if (len == 0) 1143 return; 1144 } 1145 /* Must be at least one byte following ea */ 1146 len--; 1147 if (len <= 0) 1148 return; 1149 addr >>= 1; 1150 /* Closed port, or invalid ? */ 1151 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) 1152 return; 1153 /* No error ? */ 1154 bits = *dp; 1155 if ((bits & 1) == 0) 1156 return; 1157 /* See if we have an uplink tty */ 1158 tty = tty_port_tty_get(&gsm->dlci[addr]->port); 1159 1160 if (tty) { 1161 if (bits & 2) 1162 tty_insert_flip_char(tty, 0, TTY_OVERRUN); 1163 if (bits & 4) 1164 tty_insert_flip_char(tty, 0, TTY_PARITY); 1165 if (bits & 8) 1166 tty_insert_flip_char(tty, 0, TTY_FRAME); 1167 tty_flip_buffer_push(tty); 1168 tty_kref_put(tty); 1169 } 1170 gsm_control_reply(gsm, CMD_RLS, data, clen); 1171 } 1172 1173 static void gsm_dlci_begin_close(struct gsm_dlci *dlci); 1174 1175 /** 1176 * gsm_control_message - DLCI 0 control processing 1177 * @gsm: our GSM mux 1178 * @command: the command EA 1179 * @data: data beyond the command/length EAs 1180 * @clen: length 1181 * 1182 * Input processor for control messages from the other end of the link. 1183 * Processes the incoming request and queues a response frame or an 1184 * NSC response if not supported 1185 */ 1186 1187 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, 1188 u8 *data, int clen) 1189 { 1190 u8 buf[1]; 1191 switch (command) { 1192 case CMD_CLD: { 1193 struct gsm_dlci *dlci = gsm->dlci[0]; 1194 /* Modem wishes to close down */ 1195 if (dlci) { 1196 dlci->dead = 1; 1197 gsm->dead = 1; 1198 gsm_dlci_begin_close(dlci); 1199 } 1200 } 1201 break; 1202 case CMD_TEST: 1203 /* Modem wishes to test, reply with the data */ 1204 gsm_control_reply(gsm, CMD_TEST, data, clen); 1205 break; 1206 case CMD_FCON: 1207 /* Modem wants us to STFU */ 1208 gsm->constipated = 1; 1209 gsm_control_reply(gsm, CMD_FCON, NULL, 0); 1210 break; 1211 case CMD_FCOFF: 1212 /* Modem can accept data again */ 1213 gsm->constipated = 0; 1214 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0); 1215 /* Kick the link in case it is idling */ 1216 gsm_data_kick(gsm); 1217 break; 1218 case CMD_MSC: 1219 /* Out of band modem line change indicator for a DLCI */ 1220 gsm_control_modem(gsm, data, clen); 1221 break; 1222 case CMD_RLS: 1223 /* Out of band error reception for a DLCI */ 1224 gsm_control_rls(gsm, data, clen); 1225 break; 1226 case CMD_PSC: 1227 /* Modem wishes to enter power saving state */ 1228 gsm_control_reply(gsm, CMD_PSC, NULL, 0); 1229 break; 1230 /* Optional unsupported commands */ 1231 case CMD_PN: /* Parameter negotiation */ 1232 case CMD_RPN: /* Remote port negotiation */ 1233 case CMD_SNC: /* Service negotiation command */ 1234 default: 1235 /* Reply to bad commands with an NSC */ 1236 buf[0] = command; 1237 gsm_control_reply(gsm, CMD_NSC, buf, 1); 1238 break; 1239 } 1240 } 1241 1242 /** 1243 * gsm_control_response - process a response to our control 1244 * @gsm: our GSM mux 1245 * @command: the command (response) EA 1246 * @data: data beyond the command/length EA 1247 * @clen: length 1248 * 1249 * Process a response to an outstanding command. We only allow a single 1250 * control message in flight so this is fairly easy. All the clean up 1251 * is done by the caller, we just update the fields, flag it as done 1252 * and return 1253 */ 1254 1255 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command, 1256 u8 *data, int clen) 1257 { 1258 struct gsm_control *ctrl; 1259 unsigned long flags; 1260 1261 spin_lock_irqsave(&gsm->control_lock, flags); 1262 1263 ctrl = gsm->pending_cmd; 1264 /* Does the reply match our command */ 1265 command |= 1; 1266 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) { 1267 /* Our command was replied to, kill the retry timer */ 1268 del_timer(&gsm->t2_timer); 1269 gsm->pending_cmd = NULL; 1270 /* Rejected by the other end */ 1271 if (command == CMD_NSC) 1272 ctrl->error = -EOPNOTSUPP; 1273 ctrl->done = 1; 1274 wake_up(&gsm->event); 1275 } 1276 spin_unlock_irqrestore(&gsm->control_lock, flags); 1277 } 1278 1279 /** 1280 * gsm_control_transmit - send control packet 1281 * @gsm: gsm mux 1282 * @ctrl: frame to send 1283 * 1284 * Send out a pending control command (called under control lock) 1285 */ 1286 1287 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl) 1288 { 1289 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype); 1290 if (msg == NULL) 1291 return; 1292 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */ 1293 memcpy(msg->data + 1, ctrl->data, ctrl->len); 1294 gsm_data_queue(gsm->dlci[0], msg); 1295 } 1296 1297 /** 1298 * gsm_control_retransmit - retransmit a control frame 1299 * @data: pointer to our gsm object 1300 * 1301 * Called off the T2 timer expiry in order to retransmit control frames 1302 * that have been lost in the system somewhere. The control_lock protects 1303 * us from colliding with another sender or a receive completion event. 1304 * In that situation the timer may still occur in a small window but 1305 * gsm->pending_cmd will be NULL and we just let the timer expire. 1306 */ 1307 1308 static void gsm_control_retransmit(unsigned long data) 1309 { 1310 struct gsm_mux *gsm = (struct gsm_mux *)data; 1311 struct gsm_control *ctrl; 1312 unsigned long flags; 1313 spin_lock_irqsave(&gsm->control_lock, flags); 1314 ctrl = gsm->pending_cmd; 1315 if (ctrl) { 1316 gsm->cretries--; 1317 if (gsm->cretries == 0) { 1318 gsm->pending_cmd = NULL; 1319 ctrl->error = -ETIMEDOUT; 1320 ctrl->done = 1; 1321 spin_unlock_irqrestore(&gsm->control_lock, flags); 1322 wake_up(&gsm->event); 1323 return; 1324 } 1325 gsm_control_transmit(gsm, ctrl); 1326 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); 1327 } 1328 spin_unlock_irqrestore(&gsm->control_lock, flags); 1329 } 1330 1331 /** 1332 * gsm_control_send - send a control frame on DLCI 0 1333 * @gsm: the GSM channel 1334 * @command: command to send including CR bit 1335 * @data: bytes of data (must be kmalloced) 1336 * @len: length of the block to send 1337 * 1338 * Queue and dispatch a control command. Only one command can be 1339 * active at a time. In theory more can be outstanding but the matching 1340 * gets really complicated so for now stick to one outstanding. 1341 */ 1342 1343 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm, 1344 unsigned int command, u8 *data, int clen) 1345 { 1346 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control), 1347 GFP_KERNEL); 1348 unsigned long flags; 1349 if (ctrl == NULL) 1350 return NULL; 1351 retry: 1352 wait_event(gsm->event, gsm->pending_cmd == NULL); 1353 spin_lock_irqsave(&gsm->control_lock, flags); 1354 if (gsm->pending_cmd != NULL) { 1355 spin_unlock_irqrestore(&gsm->control_lock, flags); 1356 goto retry; 1357 } 1358 ctrl->cmd = command; 1359 ctrl->data = data; 1360 ctrl->len = clen; 1361 gsm->pending_cmd = ctrl; 1362 gsm->cretries = gsm->n2; 1363 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); 1364 gsm_control_transmit(gsm, ctrl); 1365 spin_unlock_irqrestore(&gsm->control_lock, flags); 1366 return ctrl; 1367 } 1368 1369 /** 1370 * gsm_control_wait - wait for a control to finish 1371 * @gsm: GSM mux 1372 * @control: control we are waiting on 1373 * 1374 * Waits for the control to complete or time out. Frees any used 1375 * resources and returns 0 for success, or an error if the remote 1376 * rejected or ignored the request. 1377 */ 1378 1379 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control) 1380 { 1381 int err; 1382 wait_event(gsm->event, control->done == 1); 1383 err = control->error; 1384 kfree(control); 1385 return err; 1386 } 1387 1388 1389 /* 1390 * DLCI level handling: Needs krefs 1391 */ 1392 1393 /* 1394 * State transitions and timers 1395 */ 1396 1397 /** 1398 * gsm_dlci_close - a DLCI has closed 1399 * @dlci: DLCI that closed 1400 * 1401 * Perform processing when moving a DLCI into closed state. If there 1402 * is an attached tty this is hung up 1403 */ 1404 1405 static void gsm_dlci_close(struct gsm_dlci *dlci) 1406 { 1407 del_timer(&dlci->t1); 1408 if (debug & 8) 1409 pr_debug("DLCI %d goes closed.\n", dlci->addr); 1410 dlci->state = DLCI_CLOSED; 1411 if (dlci->addr != 0) { 1412 struct tty_struct *tty = tty_port_tty_get(&dlci->port); 1413 if (tty) { 1414 tty_hangup(tty); 1415 tty_kref_put(tty); 1416 } 1417 kfifo_reset(dlci->fifo); 1418 } else 1419 dlci->gsm->dead = 1; 1420 wake_up(&dlci->gsm->event); 1421 /* A DLCI 0 close is a MUX termination so we need to kick that 1422 back to userspace somehow */ 1423 } 1424 1425 /** 1426 * gsm_dlci_open - a DLCI has opened 1427 * @dlci: DLCI that opened 1428 * 1429 * Perform processing when moving a DLCI into open state. 1430 */ 1431 1432 static void gsm_dlci_open(struct gsm_dlci *dlci) 1433 { 1434 /* Note that SABM UA .. SABM UA first UA lost can mean that we go 1435 open -> open */ 1436 del_timer(&dlci->t1); 1437 /* This will let a tty open continue */ 1438 dlci->state = DLCI_OPEN; 1439 if (debug & 8) 1440 pr_debug("DLCI %d goes open.\n", dlci->addr); 1441 wake_up(&dlci->gsm->event); 1442 } 1443 1444 /** 1445 * gsm_dlci_t1 - T1 timer expiry 1446 * @dlci: DLCI that opened 1447 * 1448 * The T1 timer handles retransmits of control frames (essentially of 1449 * SABM and DISC). We resend the command until the retry count runs out 1450 * in which case an opening port goes back to closed and a closing port 1451 * is simply put into closed state (any further frames from the other 1452 * end will get a DM response) 1453 */ 1454 1455 static void gsm_dlci_t1(unsigned long data) 1456 { 1457 struct gsm_dlci *dlci = (struct gsm_dlci *)data; 1458 struct gsm_mux *gsm = dlci->gsm; 1459 1460 switch (dlci->state) { 1461 case DLCI_OPENING: 1462 dlci->retries--; 1463 if (dlci->retries) { 1464 gsm_command(dlci->gsm, dlci->addr, SABM|PF); 1465 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1466 } else 1467 gsm_dlci_close(dlci); 1468 break; 1469 case DLCI_CLOSING: 1470 dlci->retries--; 1471 if (dlci->retries) { 1472 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 1473 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1474 } else 1475 gsm_dlci_close(dlci); 1476 break; 1477 } 1478 } 1479 1480 /** 1481 * gsm_dlci_begin_open - start channel open procedure 1482 * @dlci: DLCI to open 1483 * 1484 * Commence opening a DLCI from the Linux side. We issue SABM messages 1485 * to the modem which should then reply with a UA, at which point we 1486 * will move into open state. Opening is done asynchronously with retry 1487 * running off timers and the responses. 1488 */ 1489 1490 static void gsm_dlci_begin_open(struct gsm_dlci *dlci) 1491 { 1492 struct gsm_mux *gsm = dlci->gsm; 1493 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING) 1494 return; 1495 dlci->retries = gsm->n2; 1496 dlci->state = DLCI_OPENING; 1497 gsm_command(dlci->gsm, dlci->addr, SABM|PF); 1498 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1499 } 1500 1501 /** 1502 * gsm_dlci_begin_close - start channel open procedure 1503 * @dlci: DLCI to open 1504 * 1505 * Commence closing a DLCI from the Linux side. We issue DISC messages 1506 * to the modem which should then reply with a UA, at which point we 1507 * will move into closed state. Closing is done asynchronously with retry 1508 * off timers. We may also receive a DM reply from the other end which 1509 * indicates the channel was already closed. 1510 */ 1511 1512 static void gsm_dlci_begin_close(struct gsm_dlci *dlci) 1513 { 1514 struct gsm_mux *gsm = dlci->gsm; 1515 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING) 1516 return; 1517 dlci->retries = gsm->n2; 1518 dlci->state = DLCI_CLOSING; 1519 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 1520 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1521 } 1522 1523 /** 1524 * gsm_dlci_data - data arrived 1525 * @dlci: channel 1526 * @data: block of bytes received 1527 * @len: length of received block 1528 * 1529 * A UI or UIH frame has arrived which contains data for a channel 1530 * other than the control channel. If the relevant virtual tty is 1531 * open we shovel the bits down it, if not we drop them. 1532 */ 1533 1534 static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen) 1535 { 1536 /* krefs .. */ 1537 struct tty_port *port = &dlci->port; 1538 struct tty_struct *tty = tty_port_tty_get(port); 1539 unsigned int modem = 0; 1540 int len = clen; 1541 1542 if (debug & 16) 1543 pr_debug("%d bytes for tty %p\n", len, tty); 1544 if (tty) { 1545 switch (dlci->adaption) { 1546 /* Unsupported types */ 1547 /* Packetised interruptible data */ 1548 case 4: 1549 break; 1550 /* Packetised uininterruptible voice/data */ 1551 case 3: 1552 break; 1553 /* Asynchronous serial with line state in each frame */ 1554 case 2: 1555 while (gsm_read_ea(&modem, *data++) == 0) { 1556 len--; 1557 if (len == 0) 1558 return; 1559 } 1560 gsm_process_modem(tty, dlci, modem, clen); 1561 /* Line state will go via DLCI 0 controls only */ 1562 case 1: 1563 default: 1564 tty_insert_flip_string(tty, data, len); 1565 tty_flip_buffer_push(tty); 1566 } 1567 tty_kref_put(tty); 1568 } 1569 } 1570 1571 /** 1572 * gsm_dlci_control - data arrived on control channel 1573 * @dlci: channel 1574 * @data: block of bytes received 1575 * @len: length of received block 1576 * 1577 * A UI or UIH frame has arrived which contains data for DLCI 0 the 1578 * control channel. This should contain a command EA followed by 1579 * control data bytes. The command EA contains a command/response bit 1580 * and we divide up the work accordingly. 1581 */ 1582 1583 static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len) 1584 { 1585 /* See what command is involved */ 1586 unsigned int command = 0; 1587 while (len-- > 0) { 1588 if (gsm_read_ea(&command, *data++) == 1) { 1589 int clen = *data++; 1590 len--; 1591 /* FIXME: this is properly an EA */ 1592 clen >>= 1; 1593 /* Malformed command ? */ 1594 if (clen > len) 1595 return; 1596 if (command & 1) 1597 gsm_control_message(dlci->gsm, command, 1598 data, clen); 1599 else 1600 gsm_control_response(dlci->gsm, command, 1601 data, clen); 1602 return; 1603 } 1604 } 1605 } 1606 1607 /* 1608 * Allocate/Free DLCI channels 1609 */ 1610 1611 /** 1612 * gsm_dlci_alloc - allocate a DLCI 1613 * @gsm: GSM mux 1614 * @addr: address of the DLCI 1615 * 1616 * Allocate and install a new DLCI object into the GSM mux. 1617 * 1618 * FIXME: review locking races 1619 */ 1620 1621 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr) 1622 { 1623 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC); 1624 if (dlci == NULL) 1625 return NULL; 1626 spin_lock_init(&dlci->lock); 1627 kref_init(&dlci->ref); 1628 mutex_init(&dlci->mutex); 1629 dlci->fifo = &dlci->_fifo; 1630 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) { 1631 kfree(dlci); 1632 return NULL; 1633 } 1634 1635 skb_queue_head_init(&dlci->skb_list); 1636 init_timer(&dlci->t1); 1637 dlci->t1.function = gsm_dlci_t1; 1638 dlci->t1.data = (unsigned long)dlci; 1639 tty_port_init(&dlci->port); 1640 dlci->port.ops = &gsm_port_ops; 1641 dlci->gsm = gsm; 1642 dlci->addr = addr; 1643 dlci->adaption = gsm->adaption; 1644 dlci->state = DLCI_CLOSED; 1645 if (addr) 1646 dlci->data = gsm_dlci_data; 1647 else 1648 dlci->data = gsm_dlci_command; 1649 gsm->dlci[addr] = dlci; 1650 return dlci; 1651 } 1652 1653 /** 1654 * gsm_dlci_free - free DLCI 1655 * @dlci: DLCI to free 1656 * 1657 * Free up a DLCI. 1658 * 1659 * Can sleep. 1660 */ 1661 static void gsm_dlci_free(struct kref *ref) 1662 { 1663 struct gsm_dlci *dlci = container_of(ref, struct gsm_dlci, ref); 1664 1665 del_timer_sync(&dlci->t1); 1666 dlci->gsm->dlci[dlci->addr] = NULL; 1667 kfifo_free(dlci->fifo); 1668 while ((dlci->skb = skb_dequeue(&dlci->skb_list))) 1669 kfree_skb(dlci->skb); 1670 kfree(dlci); 1671 } 1672 1673 static inline void dlci_get(struct gsm_dlci *dlci) 1674 { 1675 kref_get(&dlci->ref); 1676 } 1677 1678 static inline void dlci_put(struct gsm_dlci *dlci) 1679 { 1680 kref_put(&dlci->ref, gsm_dlci_free); 1681 } 1682 1683 /** 1684 * gsm_dlci_release - release DLCI 1685 * @dlci: DLCI to destroy 1686 * 1687 * Release a DLCI. Actual free is deferred until either 1688 * mux is closed or tty is closed - whichever is last. 1689 * 1690 * Can sleep. 1691 */ 1692 static void gsm_dlci_release(struct gsm_dlci *dlci) 1693 { 1694 struct tty_struct *tty = tty_port_tty_get(&dlci->port); 1695 if (tty) { 1696 tty_vhangup(tty); 1697 tty_kref_put(tty); 1698 } 1699 dlci_put(dlci); 1700 } 1701 1702 /* 1703 * LAPBish link layer logic 1704 */ 1705 1706 /** 1707 * gsm_queue - a GSM frame is ready to process 1708 * @gsm: pointer to our gsm mux 1709 * 1710 * At this point in time a frame has arrived and been demangled from 1711 * the line encoding. All the differences between the encodings have 1712 * been handled below us and the frame is unpacked into the structures. 1713 * The fcs holds the header FCS but any data FCS must be added here. 1714 */ 1715 1716 static void gsm_queue(struct gsm_mux *gsm) 1717 { 1718 struct gsm_dlci *dlci; 1719 u8 cr; 1720 int address; 1721 /* We have to sneak a look at the packet body to do the FCS. 1722 A somewhat layering violation in the spec */ 1723 1724 if ((gsm->control & ~PF) == UI) 1725 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len); 1726 if (gsm->encoding == 0){ 1727 /* WARNING: gsm->received_fcs is used for gsm->encoding = 0 only. 1728 In this case it contain the last piece of data 1729 required to generate final CRC */ 1730 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs); 1731 } 1732 if (gsm->fcs != GOOD_FCS) { 1733 gsm->bad_fcs++; 1734 if (debug & 4) 1735 pr_debug("BAD FCS %02x\n", gsm->fcs); 1736 return; 1737 } 1738 address = gsm->address >> 1; 1739 if (address >= NUM_DLCI) 1740 goto invalid; 1741 1742 cr = gsm->address & 1; /* C/R bit */ 1743 1744 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len); 1745 1746 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */ 1747 dlci = gsm->dlci[address]; 1748 1749 switch (gsm->control) { 1750 case SABM|PF: 1751 if (cr == 0) 1752 goto invalid; 1753 if (dlci == NULL) 1754 dlci = gsm_dlci_alloc(gsm, address); 1755 if (dlci == NULL) 1756 return; 1757 if (dlci->dead) 1758 gsm_response(gsm, address, DM); 1759 else { 1760 gsm_response(gsm, address, UA); 1761 gsm_dlci_open(dlci); 1762 } 1763 break; 1764 case DISC|PF: 1765 if (cr == 0) 1766 goto invalid; 1767 if (dlci == NULL || dlci->state == DLCI_CLOSED) { 1768 gsm_response(gsm, address, DM); 1769 return; 1770 } 1771 /* Real close complete */ 1772 gsm_response(gsm, address, UA); 1773 gsm_dlci_close(dlci); 1774 break; 1775 case UA: 1776 case UA|PF: 1777 if (cr == 0 || dlci == NULL) 1778 break; 1779 switch (dlci->state) { 1780 case DLCI_CLOSING: 1781 gsm_dlci_close(dlci); 1782 break; 1783 case DLCI_OPENING: 1784 gsm_dlci_open(dlci); 1785 break; 1786 } 1787 break; 1788 case DM: /* DM can be valid unsolicited */ 1789 case DM|PF: 1790 if (cr) 1791 goto invalid; 1792 if (dlci == NULL) 1793 return; 1794 gsm_dlci_close(dlci); 1795 break; 1796 case UI: 1797 case UI|PF: 1798 case UIH: 1799 case UIH|PF: 1800 #if 0 1801 if (cr) 1802 goto invalid; 1803 #endif 1804 if (dlci == NULL || dlci->state != DLCI_OPEN) { 1805 gsm_command(gsm, address, DM|PF); 1806 return; 1807 } 1808 dlci->data(dlci, gsm->buf, gsm->len); 1809 break; 1810 default: 1811 goto invalid; 1812 } 1813 return; 1814 invalid: 1815 gsm->malformed++; 1816 return; 1817 } 1818 1819 1820 /** 1821 * gsm0_receive - perform processing for non-transparency 1822 * @gsm: gsm data for this ldisc instance 1823 * @c: character 1824 * 1825 * Receive bytes in gsm mode 0 1826 */ 1827 1828 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) 1829 { 1830 unsigned int len; 1831 1832 switch (gsm->state) { 1833 case GSM_SEARCH: /* SOF marker */ 1834 if (c == GSM0_SOF) { 1835 gsm->state = GSM_ADDRESS; 1836 gsm->address = 0; 1837 gsm->len = 0; 1838 gsm->fcs = INIT_FCS; 1839 } 1840 break; 1841 case GSM_ADDRESS: /* Address EA */ 1842 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1843 if (gsm_read_ea(&gsm->address, c)) 1844 gsm->state = GSM_CONTROL; 1845 break; 1846 case GSM_CONTROL: /* Control Byte */ 1847 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1848 gsm->control = c; 1849 gsm->state = GSM_LEN0; 1850 break; 1851 case GSM_LEN0: /* Length EA */ 1852 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1853 if (gsm_read_ea(&gsm->len, c)) { 1854 if (gsm->len > gsm->mru) { 1855 gsm->bad_size++; 1856 gsm->state = GSM_SEARCH; 1857 break; 1858 } 1859 gsm->count = 0; 1860 if (!gsm->len) 1861 gsm->state = GSM_FCS; 1862 else 1863 gsm->state = GSM_DATA; 1864 break; 1865 } 1866 gsm->state = GSM_LEN1; 1867 break; 1868 case GSM_LEN1: 1869 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1870 len = c; 1871 gsm->len |= len << 7; 1872 if (gsm->len > gsm->mru) { 1873 gsm->bad_size++; 1874 gsm->state = GSM_SEARCH; 1875 break; 1876 } 1877 gsm->count = 0; 1878 if (!gsm->len) 1879 gsm->state = GSM_FCS; 1880 else 1881 gsm->state = GSM_DATA; 1882 break; 1883 case GSM_DATA: /* Data */ 1884 gsm->buf[gsm->count++] = c; 1885 if (gsm->count == gsm->len) 1886 gsm->state = GSM_FCS; 1887 break; 1888 case GSM_FCS: /* FCS follows the packet */ 1889 gsm->received_fcs = c; 1890 gsm_queue(gsm); 1891 gsm->state = GSM_SSOF; 1892 break; 1893 case GSM_SSOF: 1894 if (c == GSM0_SOF) { 1895 gsm->state = GSM_SEARCH; 1896 break; 1897 } 1898 break; 1899 } 1900 } 1901 1902 /** 1903 * gsm1_receive - perform processing for non-transparency 1904 * @gsm: gsm data for this ldisc instance 1905 * @c: character 1906 * 1907 * Receive bytes in mode 1 (Advanced option) 1908 */ 1909 1910 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c) 1911 { 1912 if (c == GSM1_SOF) { 1913 /* EOF is only valid in frame if we have got to the data state 1914 and received at least one byte (the FCS) */ 1915 if (gsm->state == GSM_DATA && gsm->count) { 1916 /* Extract the FCS */ 1917 gsm->count--; 1918 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]); 1919 gsm->len = gsm->count; 1920 gsm_queue(gsm); 1921 gsm->state = GSM_START; 1922 return; 1923 } 1924 /* Any partial frame was a runt so go back to start */ 1925 if (gsm->state != GSM_START) { 1926 gsm->malformed++; 1927 gsm->state = GSM_START; 1928 } 1929 /* A SOF in GSM_START means we are still reading idling or 1930 framing bytes */ 1931 return; 1932 } 1933 1934 if (c == GSM1_ESCAPE) { 1935 gsm->escape = 1; 1936 return; 1937 } 1938 1939 /* Only an unescaped SOF gets us out of GSM search */ 1940 if (gsm->state == GSM_SEARCH) 1941 return; 1942 1943 if (gsm->escape) { 1944 c ^= GSM1_ESCAPE_BITS; 1945 gsm->escape = 0; 1946 } 1947 switch (gsm->state) { 1948 case GSM_START: /* First byte after SOF */ 1949 gsm->address = 0; 1950 gsm->state = GSM_ADDRESS; 1951 gsm->fcs = INIT_FCS; 1952 /* Drop through */ 1953 case GSM_ADDRESS: /* Address continuation */ 1954 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1955 if (gsm_read_ea(&gsm->address, c)) 1956 gsm->state = GSM_CONTROL; 1957 break; 1958 case GSM_CONTROL: /* Control Byte */ 1959 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1960 gsm->control = c; 1961 gsm->count = 0; 1962 gsm->state = GSM_DATA; 1963 break; 1964 case GSM_DATA: /* Data */ 1965 if (gsm->count > gsm->mru) { /* Allow one for the FCS */ 1966 gsm->state = GSM_OVERRUN; 1967 gsm->bad_size++; 1968 } else 1969 gsm->buf[gsm->count++] = c; 1970 break; 1971 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */ 1972 break; 1973 } 1974 } 1975 1976 /** 1977 * gsm_error - handle tty error 1978 * @gsm: ldisc data 1979 * @data: byte received (may be invalid) 1980 * @flag: error received 1981 * 1982 * Handle an error in the receipt of data for a frame. Currently we just 1983 * go back to hunting for a SOF. 1984 * 1985 * FIXME: better diagnostics ? 1986 */ 1987 1988 static void gsm_error(struct gsm_mux *gsm, 1989 unsigned char data, unsigned char flag) 1990 { 1991 gsm->state = GSM_SEARCH; 1992 gsm->io_error++; 1993 } 1994 1995 /** 1996 * gsm_cleanup_mux - generic GSM protocol cleanup 1997 * @gsm: our mux 1998 * 1999 * Clean up the bits of the mux which are the same for all framing 2000 * protocols. Remove the mux from the mux table, stop all the timers 2001 * and then shut down each device hanging up the channels as we go. 2002 */ 2003 2004 void gsm_cleanup_mux(struct gsm_mux *gsm) 2005 { 2006 int i; 2007 struct gsm_dlci *dlci = gsm->dlci[0]; 2008 struct gsm_msg *txq; 2009 struct gsm_control *gc; 2010 2011 gsm->dead = 1; 2012 2013 spin_lock(&gsm_mux_lock); 2014 for (i = 0; i < MAX_MUX; i++) { 2015 if (gsm_mux[i] == gsm) { 2016 gsm_mux[i] = NULL; 2017 break; 2018 } 2019 } 2020 spin_unlock(&gsm_mux_lock); 2021 WARN_ON(i == MAX_MUX); 2022 2023 /* In theory disconnecting DLCI 0 is sufficient but for some 2024 modems this is apparently not the case. */ 2025 if (dlci) { 2026 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0); 2027 if (gc) 2028 gsm_control_wait(gsm, gc); 2029 } 2030 del_timer_sync(&gsm->t2_timer); 2031 /* Now we are sure T2 has stopped */ 2032 if (dlci) { 2033 dlci->dead = 1; 2034 gsm_dlci_begin_close(dlci); 2035 wait_event_interruptible(gsm->event, 2036 dlci->state == DLCI_CLOSED); 2037 } 2038 /* Free up any link layer users */ 2039 for (i = 0; i < NUM_DLCI; i++) 2040 if (gsm->dlci[i]) 2041 gsm_dlci_release(gsm->dlci[i]); 2042 /* Now wipe the queues */ 2043 for (txq = gsm->tx_head; txq != NULL; txq = gsm->tx_head) { 2044 gsm->tx_head = txq->next; 2045 kfree(txq); 2046 } 2047 gsm->tx_tail = NULL; 2048 } 2049 EXPORT_SYMBOL_GPL(gsm_cleanup_mux); 2050 2051 /** 2052 * gsm_activate_mux - generic GSM setup 2053 * @gsm: our mux 2054 * 2055 * Set up the bits of the mux which are the same for all framing 2056 * protocols. Add the mux to the mux table so it can be opened and 2057 * finally kick off connecting to DLCI 0 on the modem. 2058 */ 2059 2060 int gsm_activate_mux(struct gsm_mux *gsm) 2061 { 2062 struct gsm_dlci *dlci; 2063 int i = 0; 2064 2065 init_timer(&gsm->t2_timer); 2066 gsm->t2_timer.function = gsm_control_retransmit; 2067 gsm->t2_timer.data = (unsigned long)gsm; 2068 init_waitqueue_head(&gsm->event); 2069 spin_lock_init(&gsm->control_lock); 2070 spin_lock_init(&gsm->tx_lock); 2071 2072 if (gsm->encoding == 0) 2073 gsm->receive = gsm0_receive; 2074 else 2075 gsm->receive = gsm1_receive; 2076 gsm->error = gsm_error; 2077 2078 spin_lock(&gsm_mux_lock); 2079 for (i = 0; i < MAX_MUX; i++) { 2080 if (gsm_mux[i] == NULL) { 2081 gsm->num = i; 2082 gsm_mux[i] = gsm; 2083 break; 2084 } 2085 } 2086 spin_unlock(&gsm_mux_lock); 2087 if (i == MAX_MUX) 2088 return -EBUSY; 2089 2090 dlci = gsm_dlci_alloc(gsm, 0); 2091 if (dlci == NULL) 2092 return -ENOMEM; 2093 gsm->dead = 0; /* Tty opens are now permissible */ 2094 return 0; 2095 } 2096 EXPORT_SYMBOL_GPL(gsm_activate_mux); 2097 2098 /** 2099 * gsm_free_mux - free up a mux 2100 * @mux: mux to free 2101 * 2102 * Dispose of allocated resources for a dead mux 2103 */ 2104 void gsm_free_mux(struct gsm_mux *gsm) 2105 { 2106 kfree(gsm->txframe); 2107 kfree(gsm->buf); 2108 kfree(gsm); 2109 } 2110 EXPORT_SYMBOL_GPL(gsm_free_mux); 2111 2112 /** 2113 * gsm_free_muxr - free up a mux 2114 * @mux: mux to free 2115 * 2116 * Dispose of allocated resources for a dead mux 2117 */ 2118 static void gsm_free_muxr(struct kref *ref) 2119 { 2120 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref); 2121 gsm_free_mux(gsm); 2122 } 2123 2124 static inline void mux_get(struct gsm_mux *gsm) 2125 { 2126 kref_get(&gsm->ref); 2127 } 2128 2129 static inline void mux_put(struct gsm_mux *gsm) 2130 { 2131 kref_put(&gsm->ref, gsm_free_muxr); 2132 } 2133 2134 /** 2135 * gsm_alloc_mux - allocate a mux 2136 * 2137 * Creates a new mux ready for activation. 2138 */ 2139 2140 struct gsm_mux *gsm_alloc_mux(void) 2141 { 2142 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL); 2143 if (gsm == NULL) 2144 return NULL; 2145 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL); 2146 if (gsm->buf == NULL) { 2147 kfree(gsm); 2148 return NULL; 2149 } 2150 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL); 2151 if (gsm->txframe == NULL) { 2152 kfree(gsm->buf); 2153 kfree(gsm); 2154 return NULL; 2155 } 2156 spin_lock_init(&gsm->lock); 2157 kref_init(&gsm->ref); 2158 2159 gsm->t1 = T1; 2160 gsm->t2 = T2; 2161 gsm->n2 = N2; 2162 gsm->ftype = UIH; 2163 gsm->adaption = 1; 2164 gsm->encoding = 1; 2165 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */ 2166 gsm->mtu = 64; 2167 gsm->dead = 1; /* Avoid early tty opens */ 2168 2169 return gsm; 2170 } 2171 EXPORT_SYMBOL_GPL(gsm_alloc_mux); 2172 2173 /** 2174 * gsmld_output - write to link 2175 * @gsm: our mux 2176 * @data: bytes to output 2177 * @len: size 2178 * 2179 * Write a block of data from the GSM mux to the data channel. This 2180 * will eventually be serialized from above but at the moment isn't. 2181 */ 2182 2183 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len) 2184 { 2185 if (tty_write_room(gsm->tty) < len) { 2186 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags); 2187 return -ENOSPC; 2188 } 2189 if (debug & 4) 2190 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET, 2191 data, len); 2192 gsm->tty->ops->write(gsm->tty, data, len); 2193 return len; 2194 } 2195 2196 /** 2197 * gsmld_attach_gsm - mode set up 2198 * @tty: our tty structure 2199 * @gsm: our mux 2200 * 2201 * Set up the MUX for basic mode and commence connecting to the 2202 * modem. Currently called from the line discipline set up but 2203 * will need moving to an ioctl path. 2204 */ 2205 2206 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 2207 { 2208 int ret, i; 2209 int base = gsm->num << 6; /* Base for this MUX */ 2210 2211 gsm->tty = tty_kref_get(tty); 2212 gsm->output = gsmld_output; 2213 ret = gsm_activate_mux(gsm); 2214 if (ret != 0) 2215 tty_kref_put(gsm->tty); 2216 else { 2217 /* Don't register device 0 - this is the control channel and not 2218 a usable tty interface */ 2219 for (i = 1; i < NUM_DLCI; i++) 2220 tty_register_device(gsm_tty_driver, base + i, NULL); 2221 } 2222 return ret; 2223 } 2224 2225 2226 /** 2227 * gsmld_detach_gsm - stop doing 0710 mux 2228 * @tty: tty attached to the mux 2229 * @gsm: mux 2230 * 2231 * Shutdown and then clean up the resources used by the line discipline 2232 */ 2233 2234 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 2235 { 2236 int i; 2237 int base = gsm->num << 6; /* Base for this MUX */ 2238 2239 WARN_ON(tty != gsm->tty); 2240 for (i = 1; i < NUM_DLCI; i++) 2241 tty_unregister_device(gsm_tty_driver, base + i); 2242 gsm_cleanup_mux(gsm); 2243 tty_kref_put(gsm->tty); 2244 gsm->tty = NULL; 2245 } 2246 2247 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, 2248 char *fp, int count) 2249 { 2250 struct gsm_mux *gsm = tty->disc_data; 2251 const unsigned char *dp; 2252 char *f; 2253 int i; 2254 char buf[64]; 2255 char flags; 2256 2257 if (debug & 4) 2258 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET, 2259 cp, count); 2260 2261 for (i = count, dp = cp, f = fp; i; i--, dp++) { 2262 flags = *f++; 2263 switch (flags) { 2264 case TTY_NORMAL: 2265 gsm->receive(gsm, *dp); 2266 break; 2267 case TTY_OVERRUN: 2268 case TTY_BREAK: 2269 case TTY_PARITY: 2270 case TTY_FRAME: 2271 gsm->error(gsm, *dp, flags); 2272 break; 2273 default: 2274 WARN_ONCE("%s: unknown flag %d\n", 2275 tty_name(tty, buf), flags); 2276 break; 2277 } 2278 } 2279 /* FASYNC if needed ? */ 2280 /* If clogged call tty_throttle(tty); */ 2281 } 2282 2283 /** 2284 * gsmld_chars_in_buffer - report available bytes 2285 * @tty: tty device 2286 * 2287 * Report the number of characters buffered to be delivered to user 2288 * at this instant in time. 2289 * 2290 * Locking: gsm lock 2291 */ 2292 2293 static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty) 2294 { 2295 return 0; 2296 } 2297 2298 /** 2299 * gsmld_flush_buffer - clean input queue 2300 * @tty: terminal device 2301 * 2302 * Flush the input buffer. Called when the line discipline is 2303 * being closed, when the tty layer wants the buffer flushed (eg 2304 * at hangup). 2305 */ 2306 2307 static void gsmld_flush_buffer(struct tty_struct *tty) 2308 { 2309 } 2310 2311 /** 2312 * gsmld_close - close the ldisc for this tty 2313 * @tty: device 2314 * 2315 * Called from the terminal layer when this line discipline is 2316 * being shut down, either because of a close or becsuse of a 2317 * discipline change. The function will not be called while other 2318 * ldisc methods are in progress. 2319 */ 2320 2321 static void gsmld_close(struct tty_struct *tty) 2322 { 2323 struct gsm_mux *gsm = tty->disc_data; 2324 2325 gsmld_detach_gsm(tty, gsm); 2326 2327 gsmld_flush_buffer(tty); 2328 /* Do other clean up here */ 2329 mux_put(gsm); 2330 } 2331 2332 /** 2333 * gsmld_open - open an ldisc 2334 * @tty: terminal to open 2335 * 2336 * Called when this line discipline is being attached to the 2337 * terminal device. Can sleep. Called serialized so that no 2338 * other events will occur in parallel. No further open will occur 2339 * until a close. 2340 */ 2341 2342 static int gsmld_open(struct tty_struct *tty) 2343 { 2344 struct gsm_mux *gsm; 2345 2346 if (tty->ops->write == NULL) 2347 return -EINVAL; 2348 2349 /* Attach our ldisc data */ 2350 gsm = gsm_alloc_mux(); 2351 if (gsm == NULL) 2352 return -ENOMEM; 2353 2354 tty->disc_data = gsm; 2355 tty->receive_room = 65536; 2356 2357 /* Attach the initial passive connection */ 2358 gsm->encoding = 1; 2359 return gsmld_attach_gsm(tty, gsm); 2360 } 2361 2362 /** 2363 * gsmld_write_wakeup - asynchronous I/O notifier 2364 * @tty: tty device 2365 * 2366 * Required for the ptys, serial driver etc. since processes 2367 * that attach themselves to the master and rely on ASYNC 2368 * IO must be woken up 2369 */ 2370 2371 static void gsmld_write_wakeup(struct tty_struct *tty) 2372 { 2373 struct gsm_mux *gsm = tty->disc_data; 2374 unsigned long flags; 2375 2376 /* Queue poll */ 2377 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 2378 gsm_data_kick(gsm); 2379 if (gsm->tx_bytes < TX_THRESH_LO) { 2380 spin_lock_irqsave(&gsm->tx_lock, flags); 2381 gsm_dlci_data_sweep(gsm); 2382 spin_unlock_irqrestore(&gsm->tx_lock, flags); 2383 } 2384 } 2385 2386 /** 2387 * gsmld_read - read function for tty 2388 * @tty: tty device 2389 * @file: file object 2390 * @buf: userspace buffer pointer 2391 * @nr: size of I/O 2392 * 2393 * Perform reads for the line discipline. We are guaranteed that the 2394 * line discipline will not be closed under us but we may get multiple 2395 * parallel readers and must handle this ourselves. We may also get 2396 * a hangup. Always called in user context, may sleep. 2397 * 2398 * This code must be sure never to sleep through a hangup. 2399 */ 2400 2401 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, 2402 unsigned char __user *buf, size_t nr) 2403 { 2404 return -EOPNOTSUPP; 2405 } 2406 2407 /** 2408 * gsmld_write - write function for tty 2409 * @tty: tty device 2410 * @file: file object 2411 * @buf: userspace buffer pointer 2412 * @nr: size of I/O 2413 * 2414 * Called when the owner of the device wants to send a frame 2415 * itself (or some other control data). The data is transferred 2416 * as-is and must be properly framed and checksummed as appropriate 2417 * by userspace. Frames are either sent whole or not at all as this 2418 * avoids pain user side. 2419 */ 2420 2421 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file, 2422 const unsigned char *buf, size_t nr) 2423 { 2424 int space = tty_write_room(tty); 2425 if (space >= nr) 2426 return tty->ops->write(tty, buf, nr); 2427 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 2428 return -ENOBUFS; 2429 } 2430 2431 /** 2432 * gsmld_poll - poll method for N_GSM0710 2433 * @tty: terminal device 2434 * @file: file accessing it 2435 * @wait: poll table 2436 * 2437 * Called when the line discipline is asked to poll() for data or 2438 * for special events. This code is not serialized with respect to 2439 * other events save open/close. 2440 * 2441 * This code must be sure never to sleep through a hangup. 2442 * Called without the kernel lock held - fine 2443 */ 2444 2445 static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file, 2446 poll_table *wait) 2447 { 2448 unsigned int mask = 0; 2449 struct gsm_mux *gsm = tty->disc_data; 2450 2451 poll_wait(file, &tty->read_wait, wait); 2452 poll_wait(file, &tty->write_wait, wait); 2453 if (tty_hung_up_p(file)) 2454 mask |= POLLHUP; 2455 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0) 2456 mask |= POLLOUT | POLLWRNORM; 2457 if (gsm->dead) 2458 mask |= POLLHUP; 2459 return mask; 2460 } 2461 2462 static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm, 2463 struct gsm_config *c) 2464 { 2465 int need_close = 0; 2466 int need_restart = 0; 2467 2468 /* Stuff we don't support yet - UI or I frame transport, windowing */ 2469 if ((c->adaption != 1 && c->adaption != 2) || c->k) 2470 return -EOPNOTSUPP; 2471 /* Check the MRU/MTU range looks sane */ 2472 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8) 2473 return -EINVAL; 2474 if (c->n2 < 3) 2475 return -EINVAL; 2476 if (c->encapsulation > 1) /* Basic, advanced, no I */ 2477 return -EINVAL; 2478 if (c->initiator > 1) 2479 return -EINVAL; 2480 if (c->i == 0 || c->i > 2) /* UIH and UI only */ 2481 return -EINVAL; 2482 /* 2483 * See what is needed for reconfiguration 2484 */ 2485 2486 /* Timing fields */ 2487 if (c->t1 != 0 && c->t1 != gsm->t1) 2488 need_restart = 1; 2489 if (c->t2 != 0 && c->t2 != gsm->t2) 2490 need_restart = 1; 2491 if (c->encapsulation != gsm->encoding) 2492 need_restart = 1; 2493 if (c->adaption != gsm->adaption) 2494 need_restart = 1; 2495 /* Requires care */ 2496 if (c->initiator != gsm->initiator) 2497 need_close = 1; 2498 if (c->mru != gsm->mru) 2499 need_restart = 1; 2500 if (c->mtu != gsm->mtu) 2501 need_restart = 1; 2502 2503 /* 2504 * Close down what is needed, restart and initiate the new 2505 * configuration 2506 */ 2507 2508 if (need_close || need_restart) { 2509 gsm_dlci_begin_close(gsm->dlci[0]); 2510 /* This will timeout if the link is down due to N2 expiring */ 2511 wait_event_interruptible(gsm->event, 2512 gsm->dlci[0]->state == DLCI_CLOSED); 2513 if (signal_pending(current)) 2514 return -EINTR; 2515 } 2516 if (need_restart) 2517 gsm_cleanup_mux(gsm); 2518 2519 gsm->initiator = c->initiator; 2520 gsm->mru = c->mru; 2521 gsm->mtu = c->mtu; 2522 gsm->encoding = c->encapsulation; 2523 gsm->adaption = c->adaption; 2524 gsm->n2 = c->n2; 2525 2526 if (c->i == 1) 2527 gsm->ftype = UIH; 2528 else if (c->i == 2) 2529 gsm->ftype = UI; 2530 2531 if (c->t1) 2532 gsm->t1 = c->t1; 2533 if (c->t2) 2534 gsm->t2 = c->t2; 2535 2536 /* FIXME: We need to separate activation/deactivation from adding 2537 and removing from the mux array */ 2538 if (need_restart) 2539 gsm_activate_mux(gsm); 2540 if (gsm->initiator && need_close) 2541 gsm_dlci_begin_open(gsm->dlci[0]); 2542 return 0; 2543 } 2544 2545 static int gsmld_ioctl(struct tty_struct *tty, struct file *file, 2546 unsigned int cmd, unsigned long arg) 2547 { 2548 struct gsm_config c; 2549 struct gsm_mux *gsm = tty->disc_data; 2550 2551 switch (cmd) { 2552 case GSMIOC_GETCONF: 2553 memset(&c, 0, sizeof(c)); 2554 c.adaption = gsm->adaption; 2555 c.encapsulation = gsm->encoding; 2556 c.initiator = gsm->initiator; 2557 c.t1 = gsm->t1; 2558 c.t2 = gsm->t2; 2559 c.t3 = 0; /* Not supported */ 2560 c.n2 = gsm->n2; 2561 if (gsm->ftype == UIH) 2562 c.i = 1; 2563 else 2564 c.i = 2; 2565 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i); 2566 c.mru = gsm->mru; 2567 c.mtu = gsm->mtu; 2568 c.k = 0; 2569 if (copy_to_user((void *)arg, &c, sizeof(c))) 2570 return -EFAULT; 2571 return 0; 2572 case GSMIOC_SETCONF: 2573 if (copy_from_user(&c, (void *)arg, sizeof(c))) 2574 return -EFAULT; 2575 return gsmld_config(tty, gsm, &c); 2576 default: 2577 return n_tty_ioctl_helper(tty, file, cmd, arg); 2578 } 2579 } 2580 2581 /* 2582 * Network interface 2583 * 2584 */ 2585 2586 static int gsm_mux_net_open(struct net_device *net) 2587 { 2588 pr_debug("%s called\n", __func__); 2589 netif_start_queue(net); 2590 return 0; 2591 } 2592 2593 static int gsm_mux_net_close(struct net_device *net) 2594 { 2595 netif_stop_queue(net); 2596 return 0; 2597 } 2598 2599 static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net) 2600 { 2601 return &((struct gsm_mux_net *)netdev_priv(net))->stats; 2602 } 2603 static void dlci_net_free(struct gsm_dlci *dlci) 2604 { 2605 if (!dlci->net) { 2606 WARN_ON(1); 2607 return; 2608 } 2609 dlci->adaption = dlci->prev_adaption; 2610 dlci->data = dlci->prev_data; 2611 free_netdev(dlci->net); 2612 dlci->net = NULL; 2613 } 2614 static void net_free(struct kref *ref) 2615 { 2616 struct gsm_mux_net *mux_net; 2617 struct gsm_dlci *dlci; 2618 2619 mux_net = container_of(ref, struct gsm_mux_net, ref); 2620 dlci = mux_net->dlci; 2621 2622 if (dlci->net) { 2623 unregister_netdev(dlci->net); 2624 dlci_net_free(dlci); 2625 } 2626 } 2627 2628 static inline void muxnet_get(struct gsm_mux_net *mux_net) 2629 { 2630 kref_get(&mux_net->ref); 2631 } 2632 2633 static inline void muxnet_put(struct gsm_mux_net *mux_net) 2634 { 2635 kref_put(&mux_net->ref, net_free); 2636 } 2637 2638 static int gsm_mux_net_start_xmit(struct sk_buff *skb, 2639 struct net_device *net) 2640 { 2641 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net); 2642 struct gsm_dlci *dlci = mux_net->dlci; 2643 muxnet_get(mux_net); 2644 2645 skb_queue_head(&dlci->skb_list, skb); 2646 STATS(net).tx_packets++; 2647 STATS(net).tx_bytes += skb->len; 2648 gsm_dlci_data_kick(dlci); 2649 /* And tell the kernel when the last transmit started. */ 2650 net->trans_start = jiffies; 2651 muxnet_put(mux_net); 2652 return NETDEV_TX_OK; 2653 } 2654 2655 /* called when a packet did not ack after watchdogtimeout */ 2656 static void gsm_mux_net_tx_timeout(struct net_device *net) 2657 { 2658 /* Tell syslog we are hosed. */ 2659 dev_dbg(&net->dev, "Tx timed out.\n"); 2660 2661 /* Update statistics */ 2662 STATS(net).tx_errors++; 2663 } 2664 2665 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci, 2666 unsigned char *in_buf, int size) 2667 { 2668 struct net_device *net = dlci->net; 2669 struct sk_buff *skb; 2670 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net); 2671 muxnet_get(mux_net); 2672 2673 /* Allocate an sk_buff */ 2674 skb = dev_alloc_skb(size + NET_IP_ALIGN); 2675 if (!skb) { 2676 /* We got no receive buffer. */ 2677 STATS(net).rx_dropped++; 2678 muxnet_put(mux_net); 2679 return; 2680 } 2681 skb_reserve(skb, NET_IP_ALIGN); 2682 memcpy(skb_put(skb, size), in_buf, size); 2683 2684 skb->dev = net; 2685 skb->protocol = __constant_htons(ETH_P_IP); 2686 2687 /* Ship it off to the kernel */ 2688 netif_rx(skb); 2689 2690 /* update out statistics */ 2691 STATS(net).rx_packets++; 2692 STATS(net).rx_bytes += size; 2693 muxnet_put(mux_net); 2694 return; 2695 } 2696 2697 int gsm_change_mtu(struct net_device *net, int new_mtu) 2698 { 2699 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net); 2700 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu)) 2701 return -EINVAL; 2702 net->mtu = new_mtu; 2703 return 0; 2704 } 2705 2706 static void gsm_mux_net_init(struct net_device *net) 2707 { 2708 static const struct net_device_ops gsm_netdev_ops = { 2709 .ndo_open = gsm_mux_net_open, 2710 .ndo_stop = gsm_mux_net_close, 2711 .ndo_start_xmit = gsm_mux_net_start_xmit, 2712 .ndo_tx_timeout = gsm_mux_net_tx_timeout, 2713 .ndo_get_stats = gsm_mux_net_get_stats, 2714 .ndo_change_mtu = gsm_change_mtu, 2715 }; 2716 2717 net->netdev_ops = &gsm_netdev_ops; 2718 2719 /* fill in the other fields */ 2720 net->watchdog_timeo = GSM_NET_TX_TIMEOUT; 2721 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 2722 net->type = ARPHRD_NONE; 2723 net->tx_queue_len = 10; 2724 } 2725 2726 2727 /* caller holds the dlci mutex */ 2728 static void gsm_destroy_network(struct gsm_dlci *dlci) 2729 { 2730 struct gsm_mux_net *mux_net; 2731 2732 pr_debug("destroy network interface"); 2733 if (!dlci->net) 2734 return; 2735 mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net); 2736 muxnet_put(mux_net); 2737 } 2738 2739 2740 /* caller holds the dlci mutex */ 2741 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc) 2742 { 2743 char *netname; 2744 int retval = 0; 2745 struct net_device *net; 2746 struct gsm_mux_net *mux_net; 2747 2748 if (!capable(CAP_NET_ADMIN)) 2749 return -EPERM; 2750 2751 /* Already in a non tty mode */ 2752 if (dlci->adaption > 2) 2753 return -EBUSY; 2754 2755 if (nc->protocol != htons(ETH_P_IP)) 2756 return -EPROTONOSUPPORT; 2757 2758 if (nc->adaption != 3 && nc->adaption != 4) 2759 return -EPROTONOSUPPORT; 2760 2761 pr_debug("create network interface"); 2762 2763 netname = "gsm%d"; 2764 if (nc->if_name[0] != '\0') 2765 netname = nc->if_name; 2766 net = alloc_netdev(sizeof(struct gsm_mux_net), 2767 netname, 2768 gsm_mux_net_init); 2769 if (!net) { 2770 pr_err("alloc_netdev failed"); 2771 return -ENOMEM; 2772 } 2773 net->mtu = dlci->gsm->mtu; 2774 mux_net = (struct gsm_mux_net *)netdev_priv(net); 2775 mux_net->dlci = dlci; 2776 kref_init(&mux_net->ref); 2777 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */ 2778 2779 /* reconfigure dlci for network */ 2780 dlci->prev_adaption = dlci->adaption; 2781 dlci->prev_data = dlci->data; 2782 dlci->adaption = nc->adaption; 2783 dlci->data = gsm_mux_rx_netchar; 2784 dlci->net = net; 2785 2786 pr_debug("register netdev"); 2787 retval = register_netdev(net); 2788 if (retval) { 2789 pr_err("network register fail %d\n", retval); 2790 dlci_net_free(dlci); 2791 return retval; 2792 } 2793 return net->ifindex; /* return network index */ 2794 } 2795 2796 /* Line discipline for real tty */ 2797 struct tty_ldisc_ops tty_ldisc_packet = { 2798 .owner = THIS_MODULE, 2799 .magic = TTY_LDISC_MAGIC, 2800 .name = "n_gsm", 2801 .open = gsmld_open, 2802 .close = gsmld_close, 2803 .flush_buffer = gsmld_flush_buffer, 2804 .chars_in_buffer = gsmld_chars_in_buffer, 2805 .read = gsmld_read, 2806 .write = gsmld_write, 2807 .ioctl = gsmld_ioctl, 2808 .poll = gsmld_poll, 2809 .receive_buf = gsmld_receive_buf, 2810 .write_wakeup = gsmld_write_wakeup 2811 }; 2812 2813 /* 2814 * Virtual tty side 2815 */ 2816 2817 #define TX_SIZE 512 2818 2819 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) 2820 { 2821 u8 modembits[5]; 2822 struct gsm_control *ctrl; 2823 int len = 2; 2824 2825 if (brk) 2826 len++; 2827 2828 modembits[0] = len << 1 | EA; /* Data bytes */ 2829 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */ 2830 modembits[2] = gsm_encode_modem(dlci) << 1 | EA; 2831 if (brk) 2832 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */ 2833 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1); 2834 if (ctrl == NULL) 2835 return -ENOMEM; 2836 return gsm_control_wait(dlci->gsm, ctrl); 2837 } 2838 2839 static int gsm_carrier_raised(struct tty_port *port) 2840 { 2841 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2842 /* Not yet open so no carrier info */ 2843 if (dlci->state != DLCI_OPEN) 2844 return 0; 2845 if (debug & 2) 2846 return 1; 2847 return dlci->modem_rx & TIOCM_CD; 2848 } 2849 2850 static void gsm_dtr_rts(struct tty_port *port, int onoff) 2851 { 2852 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2853 unsigned int modem_tx = dlci->modem_tx; 2854 if (onoff) 2855 modem_tx |= TIOCM_DTR | TIOCM_RTS; 2856 else 2857 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); 2858 if (modem_tx != dlci->modem_tx) { 2859 dlci->modem_tx = modem_tx; 2860 gsmtty_modem_update(dlci, 0); 2861 } 2862 } 2863 2864 static const struct tty_port_operations gsm_port_ops = { 2865 .carrier_raised = gsm_carrier_raised, 2866 .dtr_rts = gsm_dtr_rts, 2867 }; 2868 2869 2870 static int gsmtty_open(struct tty_struct *tty, struct file *filp) 2871 { 2872 struct gsm_mux *gsm; 2873 struct gsm_dlci *dlci; 2874 struct tty_port *port; 2875 unsigned int line = tty->index; 2876 unsigned int mux = line >> 6; 2877 2878 line = line & 0x3F; 2879 2880 if (mux >= MAX_MUX) 2881 return -ENXIO; 2882 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */ 2883 if (gsm_mux[mux] == NULL) 2884 return -EUNATCH; 2885 if (line == 0 || line > 61) /* 62/63 reserved */ 2886 return -ECHRNG; 2887 gsm = gsm_mux[mux]; 2888 if (gsm->dead) 2889 return -EL2HLT; 2890 dlci = gsm->dlci[line]; 2891 if (dlci == NULL) 2892 dlci = gsm_dlci_alloc(gsm, line); 2893 if (dlci == NULL) 2894 return -ENOMEM; 2895 port = &dlci->port; 2896 port->count++; 2897 tty->driver_data = dlci; 2898 dlci_get(dlci); 2899 dlci_get(dlci->gsm->dlci[0]); 2900 mux_get(dlci->gsm); 2901 tty_port_tty_set(port, tty); 2902 2903 dlci->modem_rx = 0; 2904 /* We could in theory open and close before we wait - eg if we get 2905 a DM straight back. This is ok as that will have caused a hangup */ 2906 set_bit(ASYNCB_INITIALIZED, &port->flags); 2907 /* Start sending off SABM messages */ 2908 gsm_dlci_begin_open(dlci); 2909 /* And wait for virtual carrier */ 2910 return tty_port_block_til_ready(port, tty, filp); 2911 } 2912 2913 static void gsmtty_close(struct tty_struct *tty, struct file *filp) 2914 { 2915 struct gsm_dlci *dlci = tty->driver_data; 2916 struct gsm_mux *gsm; 2917 2918 if (dlci == NULL) 2919 return; 2920 mutex_lock(&dlci->mutex); 2921 gsm_destroy_network(dlci); 2922 mutex_unlock(&dlci->mutex); 2923 gsm = dlci->gsm; 2924 if (tty_port_close_start(&dlci->port, tty, filp) == 0) 2925 goto out; 2926 gsm_dlci_begin_close(dlci); 2927 tty_port_close_end(&dlci->port, tty); 2928 tty_port_tty_set(&dlci->port, NULL); 2929 out: 2930 dlci_put(dlci); 2931 dlci_put(gsm->dlci[0]); 2932 mux_put(gsm); 2933 } 2934 2935 static void gsmtty_hangup(struct tty_struct *tty) 2936 { 2937 struct gsm_dlci *dlci = tty->driver_data; 2938 tty_port_hangup(&dlci->port); 2939 gsm_dlci_begin_close(dlci); 2940 } 2941 2942 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf, 2943 int len) 2944 { 2945 struct gsm_dlci *dlci = tty->driver_data; 2946 /* Stuff the bytes into the fifo queue */ 2947 int sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock); 2948 /* Need to kick the channel */ 2949 gsm_dlci_data_kick(dlci); 2950 return sent; 2951 } 2952 2953 static int gsmtty_write_room(struct tty_struct *tty) 2954 { 2955 struct gsm_dlci *dlci = tty->driver_data; 2956 return TX_SIZE - kfifo_len(dlci->fifo); 2957 } 2958 2959 static int gsmtty_chars_in_buffer(struct tty_struct *tty) 2960 { 2961 struct gsm_dlci *dlci = tty->driver_data; 2962 return kfifo_len(dlci->fifo); 2963 } 2964 2965 static void gsmtty_flush_buffer(struct tty_struct *tty) 2966 { 2967 struct gsm_dlci *dlci = tty->driver_data; 2968 /* Caution needed: If we implement reliable transport classes 2969 then the data being transmitted can't simply be junked once 2970 it has first hit the stack. Until then we can just blow it 2971 away */ 2972 kfifo_reset(dlci->fifo); 2973 /* Need to unhook this DLCI from the transmit queue logic */ 2974 } 2975 2976 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout) 2977 { 2978 /* The FIFO handles the queue so the kernel will do the right 2979 thing waiting on chars_in_buffer before calling us. No work 2980 to do here */ 2981 } 2982 2983 static int gsmtty_tiocmget(struct tty_struct *tty) 2984 { 2985 struct gsm_dlci *dlci = tty->driver_data; 2986 return dlci->modem_rx; 2987 } 2988 2989 static int gsmtty_tiocmset(struct tty_struct *tty, 2990 unsigned int set, unsigned int clear) 2991 { 2992 struct gsm_dlci *dlci = tty->driver_data; 2993 unsigned int modem_tx = dlci->modem_tx; 2994 2995 modem_tx &= ~clear; 2996 modem_tx |= set; 2997 2998 if (modem_tx != dlci->modem_tx) { 2999 dlci->modem_tx = modem_tx; 3000 return gsmtty_modem_update(dlci, 0); 3001 } 3002 return 0; 3003 } 3004 3005 3006 static int gsmtty_ioctl(struct tty_struct *tty, 3007 unsigned int cmd, unsigned long arg) 3008 { 3009 struct gsm_dlci *dlci = tty->driver_data; 3010 struct gsm_netconfig nc; 3011 int index; 3012 3013 switch (cmd) { 3014 case GSMIOC_ENABLE_NET: 3015 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc))) 3016 return -EFAULT; 3017 nc.if_name[IFNAMSIZ-1] = '\0'; 3018 /* return net interface index or error code */ 3019 mutex_lock(&dlci->mutex); 3020 index = gsm_create_network(dlci, &nc); 3021 mutex_unlock(&dlci->mutex); 3022 if (copy_to_user((void __user *)arg, &nc, sizeof(nc))) 3023 return -EFAULT; 3024 return index; 3025 case GSMIOC_DISABLE_NET: 3026 if (!capable(CAP_NET_ADMIN)) 3027 return -EPERM; 3028 mutex_lock(&dlci->mutex); 3029 gsm_destroy_network(dlci); 3030 mutex_unlock(&dlci->mutex); 3031 return 0; 3032 default: 3033 return -ENOIOCTLCMD; 3034 } 3035 } 3036 3037 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old) 3038 { 3039 /* For the moment its fixed. In actual fact the speed information 3040 for the virtual channel can be propogated in both directions by 3041 the RPN control message. This however rapidly gets nasty as we 3042 then have to remap modem signals each way according to whether 3043 our virtual cable is null modem etc .. */ 3044 tty_termios_copy_hw(tty->termios, old); 3045 } 3046 3047 static void gsmtty_throttle(struct tty_struct *tty) 3048 { 3049 struct gsm_dlci *dlci = tty->driver_data; 3050 if (tty->termios->c_cflag & CRTSCTS) 3051 dlci->modem_tx &= ~TIOCM_DTR; 3052 dlci->throttled = 1; 3053 /* Send an MSC with DTR cleared */ 3054 gsmtty_modem_update(dlci, 0); 3055 } 3056 3057 static void gsmtty_unthrottle(struct tty_struct *tty) 3058 { 3059 struct gsm_dlci *dlci = tty->driver_data; 3060 if (tty->termios->c_cflag & CRTSCTS) 3061 dlci->modem_tx |= TIOCM_DTR; 3062 dlci->throttled = 0; 3063 /* Send an MSC with DTR set */ 3064 gsmtty_modem_update(dlci, 0); 3065 } 3066 3067 static int gsmtty_break_ctl(struct tty_struct *tty, int state) 3068 { 3069 struct gsm_dlci *dlci = tty->driver_data; 3070 int encode = 0; /* Off */ 3071 3072 if (state == -1) /* "On indefinitely" - we can't encode this 3073 properly */ 3074 encode = 0x0F; 3075 else if (state > 0) { 3076 encode = state / 200; /* mS to encoding */ 3077 if (encode > 0x0F) 3078 encode = 0x0F; /* Best effort */ 3079 } 3080 return gsmtty_modem_update(dlci, encode); 3081 } 3082 3083 3084 /* Virtual ttys for the demux */ 3085 static const struct tty_operations gsmtty_ops = { 3086 .open = gsmtty_open, 3087 .close = gsmtty_close, 3088 .write = gsmtty_write, 3089 .write_room = gsmtty_write_room, 3090 .chars_in_buffer = gsmtty_chars_in_buffer, 3091 .flush_buffer = gsmtty_flush_buffer, 3092 .ioctl = gsmtty_ioctl, 3093 .throttle = gsmtty_throttle, 3094 .unthrottle = gsmtty_unthrottle, 3095 .set_termios = gsmtty_set_termios, 3096 .hangup = gsmtty_hangup, 3097 .wait_until_sent = gsmtty_wait_until_sent, 3098 .tiocmget = gsmtty_tiocmget, 3099 .tiocmset = gsmtty_tiocmset, 3100 .break_ctl = gsmtty_break_ctl, 3101 }; 3102 3103 3104 3105 static int __init gsm_init(void) 3106 { 3107 /* Fill in our line protocol discipline, and register it */ 3108 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet); 3109 if (status != 0) { 3110 pr_err("n_gsm: can't register line discipline (err = %d)\n", 3111 status); 3112 return status; 3113 } 3114 3115 gsm_tty_driver = alloc_tty_driver(256); 3116 if (!gsm_tty_driver) { 3117 tty_unregister_ldisc(N_GSM0710); 3118 pr_err("gsm_init: tty allocation failed.\n"); 3119 return -EINVAL; 3120 } 3121 gsm_tty_driver->owner = THIS_MODULE; 3122 gsm_tty_driver->driver_name = "gsmtty"; 3123 gsm_tty_driver->name = "gsmtty"; 3124 gsm_tty_driver->major = 0; /* Dynamic */ 3125 gsm_tty_driver->minor_start = 0; 3126 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; 3127 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL; 3128 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV 3129 | TTY_DRIVER_HARDWARE_BREAK; 3130 gsm_tty_driver->init_termios = tty_std_termios; 3131 /* Fixme */ 3132 gsm_tty_driver->init_termios.c_lflag &= ~ECHO; 3133 tty_set_operations(gsm_tty_driver, &gsmtty_ops); 3134 3135 spin_lock_init(&gsm_mux_lock); 3136 3137 if (tty_register_driver(gsm_tty_driver)) { 3138 put_tty_driver(gsm_tty_driver); 3139 tty_unregister_ldisc(N_GSM0710); 3140 pr_err("gsm_init: tty registration failed.\n"); 3141 return -EBUSY; 3142 } 3143 pr_debug("gsm_init: loaded as %d,%d.\n", 3144 gsm_tty_driver->major, gsm_tty_driver->minor_start); 3145 return 0; 3146 } 3147 3148 static void __exit gsm_exit(void) 3149 { 3150 int status = tty_unregister_ldisc(N_GSM0710); 3151 if (status != 0) 3152 pr_err("n_gsm: can't unregister line discipline (err = %d)\n", 3153 status); 3154 tty_unregister_driver(gsm_tty_driver); 3155 put_tty_driver(gsm_tty_driver); 3156 } 3157 3158 module_init(gsm_init); 3159 module_exit(gsm_exit); 3160 3161 3162 MODULE_LICENSE("GPL"); 3163 MODULE_ALIAS_LDISC(N_GSM0710); 3164