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