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