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 struct mutex mutex; 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 list_head tx_list; /* Pending data packets */ 249 250 /* Control messages */ 251 struct timer_list t2_timer; /* Retransmit timer for commands */ 252 int cretries; /* Command retry counter */ 253 struct gsm_control *pending_cmd;/* Our current pending command */ 254 spinlock_t control_lock; /* Protects the pending command */ 255 256 /* Configuration */ 257 int adaption; /* 1 or 2 supported */ 258 u8 ftype; /* UI or UIH */ 259 int t1, t2; /* Timers in 1/100th of a sec */ 260 int n2; /* Retry count */ 261 262 /* Statistics (not currently exposed) */ 263 unsigned long bad_fcs; 264 unsigned long malformed; 265 unsigned long io_error; 266 unsigned long bad_size; 267 unsigned long unsupported; 268 }; 269 270 271 /* 272 * Mux objects - needed so that we can translate a tty index into the 273 * relevant mux and DLCI. 274 */ 275 276 #define MAX_MUX 4 /* 256 minors */ 277 static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */ 278 static spinlock_t gsm_mux_lock; 279 280 static struct tty_driver *gsm_tty_driver; 281 282 /* 283 * This section of the driver logic implements the GSM encodings 284 * both the basic and the 'advanced'. Reliable transport is not 285 * supported. 286 */ 287 288 #define CR 0x02 289 #define EA 0x01 290 #define PF 0x10 291 292 /* I is special: the rest are ..*/ 293 #define RR 0x01 294 #define UI 0x03 295 #define RNR 0x05 296 #define REJ 0x09 297 #define DM 0x0F 298 #define SABM 0x2F 299 #define DISC 0x43 300 #define UA 0x63 301 #define UIH 0xEF 302 303 /* Channel commands */ 304 #define CMD_NSC 0x09 305 #define CMD_TEST 0x11 306 #define CMD_PSC 0x21 307 #define CMD_RLS 0x29 308 #define CMD_FCOFF 0x31 309 #define CMD_PN 0x41 310 #define CMD_RPN 0x49 311 #define CMD_FCON 0x51 312 #define CMD_CLD 0x61 313 #define CMD_SNC 0x69 314 #define CMD_MSC 0x71 315 316 /* Virtual modem bits */ 317 #define MDM_FC 0x01 318 #define MDM_RTC 0x02 319 #define MDM_RTR 0x04 320 #define MDM_IC 0x20 321 #define MDM_DV 0x40 322 323 #define GSM0_SOF 0xF9 324 #define GSM1_SOF 0x7E 325 #define GSM1_ESCAPE 0x7D 326 #define GSM1_ESCAPE_BITS 0x20 327 #define XON 0x11 328 #define XOFF 0x13 329 330 static const struct tty_port_operations gsm_port_ops; 331 332 /* 333 * CRC table for GSM 0710 334 */ 335 336 static const u8 gsm_fcs8[256] = { 337 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75, 338 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B, 339 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69, 340 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67, 341 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D, 342 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43, 343 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51, 344 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F, 345 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05, 346 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B, 347 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19, 348 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17, 349 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D, 350 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33, 351 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21, 352 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F, 353 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95, 354 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B, 355 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89, 356 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87, 357 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD, 358 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3, 359 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1, 360 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF, 361 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5, 362 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB, 363 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9, 364 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7, 365 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD, 366 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3, 367 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1, 368 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF 369 }; 370 371 #define INIT_FCS 0xFF 372 #define GOOD_FCS 0xCF 373 374 /** 375 * gsm_fcs_add - update FCS 376 * @fcs: Current FCS 377 * @c: Next data 378 * 379 * Update the FCS to include c. Uses the algorithm in the specification 380 * notes. 381 */ 382 383 static inline u8 gsm_fcs_add(u8 fcs, u8 c) 384 { 385 return gsm_fcs8[fcs ^ c]; 386 } 387 388 /** 389 * gsm_fcs_add_block - update FCS for a block 390 * @fcs: Current FCS 391 * @c: buffer of data 392 * @len: length of buffer 393 * 394 * Update the FCS to include c. Uses the algorithm in the specification 395 * notes. 396 */ 397 398 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len) 399 { 400 while (len--) 401 fcs = gsm_fcs8[fcs ^ *c++]; 402 return fcs; 403 } 404 405 /** 406 * gsm_read_ea - read a byte into an EA 407 * @val: variable holding value 408 * c: byte going into the EA 409 * 410 * Processes one byte of an EA. Updates the passed variable 411 * and returns 1 if the EA is now completely read 412 */ 413 414 static int gsm_read_ea(unsigned int *val, u8 c) 415 { 416 /* Add the next 7 bits into the value */ 417 *val <<= 7; 418 *val |= c >> 1; 419 /* Was this the last byte of the EA 1 = yes*/ 420 return c & EA; 421 } 422 423 /** 424 * gsm_encode_modem - encode modem data bits 425 * @dlci: DLCI to encode from 426 * 427 * Returns the correct GSM encoded modem status bits (6 bit field) for 428 * the current status of the DLCI and attached tty object 429 */ 430 431 static u8 gsm_encode_modem(const struct gsm_dlci *dlci) 432 { 433 u8 modembits = 0; 434 /* FC is true flow control not modem bits */ 435 if (dlci->throttled) 436 modembits |= MDM_FC; 437 if (dlci->modem_tx & TIOCM_DTR) 438 modembits |= MDM_RTC; 439 if (dlci->modem_tx & TIOCM_RTS) 440 modembits |= MDM_RTR; 441 if (dlci->modem_tx & TIOCM_RI) 442 modembits |= MDM_IC; 443 if (dlci->modem_tx & TIOCM_CD) 444 modembits |= MDM_DV; 445 return modembits; 446 } 447 448 /** 449 * gsm_print_packet - display a frame for debug 450 * @hdr: header to print before decode 451 * @addr: address EA from the frame 452 * @cr: C/R bit from the frame 453 * @control: control including PF bit 454 * @data: following data bytes 455 * @dlen: length of data 456 * 457 * Displays a packet in human readable format for debugging purposes. The 458 * style is based on amateur radio LAP-B dump display. 459 */ 460 461 static void gsm_print_packet(const char *hdr, int addr, int cr, 462 u8 control, const u8 *data, int dlen) 463 { 464 if (!(debug & 1)) 465 return; 466 467 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]); 468 469 switch (control & ~PF) { 470 case SABM: 471 pr_cont("SABM"); 472 break; 473 case UA: 474 pr_cont("UA"); 475 break; 476 case DISC: 477 pr_cont("DISC"); 478 break; 479 case DM: 480 pr_cont("DM"); 481 break; 482 case UI: 483 pr_cont("UI"); 484 break; 485 case UIH: 486 pr_cont("UIH"); 487 break; 488 default: 489 if (!(control & 0x01)) { 490 pr_cont("I N(S)%d N(R)%d", 491 (control & 0x0E) >> 1, (control & 0xE0) >> 5); 492 } else switch (control & 0x0F) { 493 case RR: 494 pr_cont("RR(%d)", (control & 0xE0) >> 5); 495 break; 496 case RNR: 497 pr_cont("RNR(%d)", (control & 0xE0) >> 5); 498 break; 499 case REJ: 500 pr_cont("REJ(%d)", (control & 0xE0) >> 5); 501 break; 502 default: 503 pr_cont("[%02X]", control); 504 } 505 } 506 507 if (control & PF) 508 pr_cont("(P)"); 509 else 510 pr_cont("(F)"); 511 512 if (dlen) { 513 int ct = 0; 514 while (dlen--) { 515 if (ct % 8 == 0) { 516 pr_cont("\n"); 517 pr_debug(" "); 518 } 519 pr_cont("%02X ", *data++); 520 ct++; 521 } 522 } 523 pr_cont("\n"); 524 } 525 526 527 /* 528 * Link level transmission side 529 */ 530 531 /** 532 * gsm_stuff_packet - bytestuff a packet 533 * @ibuf: input 534 * @obuf: output 535 * @len: length of input 536 * 537 * Expand a buffer by bytestuffing it. The worst case size change 538 * is doubling and the caller is responsible for handing out 539 * suitable sized buffers. 540 */ 541 542 static int gsm_stuff_frame(const u8 *input, u8 *output, int len) 543 { 544 int olen = 0; 545 while (len--) { 546 if (*input == GSM1_SOF || *input == GSM1_ESCAPE 547 || *input == XON || *input == XOFF) { 548 *output++ = GSM1_ESCAPE; 549 *output++ = *input++ ^ GSM1_ESCAPE_BITS; 550 olen++; 551 } else 552 *output++ = *input++; 553 olen++; 554 } 555 return olen; 556 } 557 558 /** 559 * gsm_send - send a control frame 560 * @gsm: our GSM mux 561 * @addr: address for control frame 562 * @cr: command/response bit 563 * @control: control byte including PF bit 564 * 565 * Format up and transmit a control frame. These do not go via the 566 * queueing logic as they should be transmitted ahead of data when 567 * they are needed. 568 * 569 * FIXME: Lock versus data TX path 570 */ 571 572 static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control) 573 { 574 int len; 575 u8 cbuf[10]; 576 u8 ibuf[3]; 577 578 switch (gsm->encoding) { 579 case 0: 580 cbuf[0] = GSM0_SOF; 581 cbuf[1] = (addr << 2) | (cr << 1) | EA; 582 cbuf[2] = control; 583 cbuf[3] = EA; /* Length of data = 0 */ 584 cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3); 585 cbuf[5] = GSM0_SOF; 586 len = 6; 587 break; 588 case 1: 589 case 2: 590 /* Control frame + packing (but not frame stuffing) in mode 1 */ 591 ibuf[0] = (addr << 2) | (cr << 1) | EA; 592 ibuf[1] = control; 593 ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2); 594 /* Stuffing may double the size worst case */ 595 len = gsm_stuff_frame(ibuf, cbuf + 1, 3); 596 /* Now add the SOF markers */ 597 cbuf[0] = GSM1_SOF; 598 cbuf[len + 1] = GSM1_SOF; 599 /* FIXME: we can omit the lead one in many cases */ 600 len += 2; 601 break; 602 default: 603 WARN_ON(1); 604 return; 605 } 606 gsm->output(gsm, cbuf, len); 607 gsm_print_packet("-->", addr, cr, control, NULL, 0); 608 } 609 610 /** 611 * gsm_response - send a control response 612 * @gsm: our GSM mux 613 * @addr: address for control frame 614 * @control: control byte including PF bit 615 * 616 * Format up and transmit a link level response frame. 617 */ 618 619 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control) 620 { 621 gsm_send(gsm, addr, 0, control); 622 } 623 624 /** 625 * gsm_command - send a control command 626 * @gsm: our GSM mux 627 * @addr: address for control frame 628 * @control: control byte including PF bit 629 * 630 * Format up and transmit a link level command frame. 631 */ 632 633 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control) 634 { 635 gsm_send(gsm, addr, 1, control); 636 } 637 638 /* Data transmission */ 639 640 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */ 641 642 /** 643 * gsm_data_alloc - allocate data frame 644 * @gsm: GSM mux 645 * @addr: DLCI address 646 * @len: length excluding header and FCS 647 * @ctrl: control byte 648 * 649 * Allocate a new data buffer for sending frames with data. Space is left 650 * at the front for header bytes but that is treated as an implementation 651 * detail and not for the high level code to use 652 */ 653 654 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len, 655 u8 ctrl) 656 { 657 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN, 658 GFP_ATOMIC); 659 if (m == NULL) 660 return NULL; 661 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */ 662 m->len = len; 663 m->addr = addr; 664 m->ctrl = ctrl; 665 INIT_LIST_HEAD(&m->list); 666 return m; 667 } 668 669 /** 670 * gsm_data_kick - poke the queue 671 * @gsm: GSM Mux 672 * 673 * The tty device has called us to indicate that room has appeared in 674 * the transmit queue. Ram more data into the pipe if we have any 675 * If we have been flow-stopped by a CMD_FCOFF, then we can only 676 * send messages on DLCI0 until CMD_FCON 677 * 678 * FIXME: lock against link layer control transmissions 679 */ 680 681 static void gsm_data_kick(struct gsm_mux *gsm) 682 { 683 struct gsm_msg *msg, *nmsg; 684 int len; 685 int skip_sof = 0; 686 687 list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) { 688 if (gsm->constipated && msg->addr) 689 continue; 690 if (gsm->encoding != 0) { 691 gsm->txframe[0] = GSM1_SOF; 692 len = gsm_stuff_frame(msg->data, 693 gsm->txframe + 1, msg->len); 694 gsm->txframe[len + 1] = GSM1_SOF; 695 len += 2; 696 } else { 697 gsm->txframe[0] = GSM0_SOF; 698 memcpy(gsm->txframe + 1 , msg->data, msg->len); 699 gsm->txframe[msg->len + 1] = GSM0_SOF; 700 len = msg->len + 2; 701 } 702 703 if (debug & 4) 704 print_hex_dump_bytes("gsm_data_kick: ", 705 DUMP_PREFIX_OFFSET, 706 gsm->txframe, len); 707 708 if (gsm->output(gsm, gsm->txframe + skip_sof, 709 len - skip_sof) < 0) 710 break; 711 /* FIXME: Can eliminate one SOF in many more cases */ 712 gsm->tx_bytes -= msg->len; 713 /* For a burst of frames skip the extra SOF within the 714 burst */ 715 skip_sof = 1; 716 717 list_del(&msg->list); 718 kfree(msg); 719 } 720 } 721 722 /** 723 * __gsm_data_queue - queue a UI or UIH frame 724 * @dlci: DLCI sending the data 725 * @msg: message queued 726 * 727 * Add data to the transmit queue and try and get stuff moving 728 * out of the mux tty if not already doing so. The Caller must hold 729 * the gsm tx lock. 730 */ 731 732 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) 733 { 734 struct gsm_mux *gsm = dlci->gsm; 735 u8 *dp = msg->data; 736 u8 *fcs = dp + msg->len; 737 738 /* Fill in the header */ 739 if (gsm->encoding == 0) { 740 if (msg->len < 128) 741 *--dp = (msg->len << 1) | EA; 742 else { 743 *--dp = (msg->len >> 7); /* bits 7 - 15 */ 744 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */ 745 } 746 } 747 748 *--dp = msg->ctrl; 749 if (gsm->initiator) 750 *--dp = (msg->addr << 2) | 2 | EA; 751 else 752 *--dp = (msg->addr << 2) | EA; 753 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp); 754 /* Ugly protocol layering violation */ 755 if (msg->ctrl == UI || msg->ctrl == (UI|PF)) 756 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len); 757 *fcs = 0xFF - *fcs; 758 759 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl, 760 msg->data, msg->len); 761 762 /* Move the header back and adjust the length, also allow for the FCS 763 now tacked on the end */ 764 msg->len += (msg->data - dp) + 1; 765 msg->data = dp; 766 767 /* Add to the actual output queue */ 768 list_add_tail(&msg->list, &gsm->tx_list); 769 gsm->tx_bytes += msg->len; 770 gsm_data_kick(gsm); 771 } 772 773 /** 774 * gsm_data_queue - queue a UI or UIH frame 775 * @dlci: DLCI sending the data 776 * @msg: message queued 777 * 778 * Add data to the transmit queue and try and get stuff moving 779 * out of the mux tty if not already doing so. Take the 780 * the gsm tx lock and dlci lock. 781 */ 782 783 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) 784 { 785 unsigned long flags; 786 spin_lock_irqsave(&dlci->gsm->tx_lock, flags); 787 __gsm_data_queue(dlci, msg); 788 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); 789 } 790 791 /** 792 * gsm_dlci_data_output - try and push data out of a DLCI 793 * @gsm: mux 794 * @dlci: the DLCI to pull data from 795 * 796 * Pull data from a DLCI and send it into the transmit queue if there 797 * is data. Keep to the MRU of the mux. This path handles the usual tty 798 * interface which is a byte stream with optional modem data. 799 * 800 * Caller must hold the tx_lock of the mux. 801 */ 802 803 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci) 804 { 805 struct gsm_msg *msg; 806 u8 *dp; 807 int len, total_size, size; 808 int h = dlci->adaption - 1; 809 810 total_size = 0; 811 while (1) { 812 len = kfifo_len(dlci->fifo); 813 if (len == 0) 814 return total_size; 815 816 /* MTU/MRU count only the data bits */ 817 if (len > gsm->mtu) 818 len = gsm->mtu; 819 820 size = len + h; 821 822 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); 823 /* FIXME: need a timer or something to kick this so it can't 824 get stuck with no work outstanding and no buffer free */ 825 if (msg == NULL) 826 return -ENOMEM; 827 dp = msg->data; 828 switch (dlci->adaption) { 829 case 1: /* Unstructured */ 830 break; 831 case 2: /* Unstructed with modem bits. 832 Always one byte as we never send inline break data */ 833 *dp++ = gsm_encode_modem(dlci); 834 break; 835 } 836 WARN_ON(kfifo_out_locked(dlci->fifo, dp , len, &dlci->lock) != len); 837 __gsm_data_queue(dlci, msg); 838 total_size += size; 839 } 840 /* Bytes of data we used up */ 841 return total_size; 842 } 843 844 /** 845 * gsm_dlci_data_output_framed - try and push data out of a DLCI 846 * @gsm: mux 847 * @dlci: the DLCI to pull data from 848 * 849 * Pull data from a DLCI and send it into the transmit queue if there 850 * is data. Keep to the MRU of the mux. This path handles framed data 851 * queued as skbuffs to the DLCI. 852 * 853 * Caller must hold the tx_lock of the mux. 854 */ 855 856 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, 857 struct gsm_dlci *dlci) 858 { 859 struct gsm_msg *msg; 860 u8 *dp; 861 int len, size; 862 int last = 0, first = 0; 863 int overhead = 0; 864 865 /* One byte per frame is used for B/F flags */ 866 if (dlci->adaption == 4) 867 overhead = 1; 868 869 /* dlci->skb is locked by tx_lock */ 870 if (dlci->skb == NULL) { 871 dlci->skb = skb_dequeue_tail(&dlci->skb_list); 872 if (dlci->skb == NULL) 873 return 0; 874 first = 1; 875 } 876 len = dlci->skb->len + overhead; 877 878 /* MTU/MRU count only the data bits */ 879 if (len > gsm->mtu) { 880 if (dlci->adaption == 3) { 881 /* Over long frame, bin it */ 882 dev_kfree_skb_any(dlci->skb); 883 dlci->skb = NULL; 884 return 0; 885 } 886 len = gsm->mtu; 887 } else 888 last = 1; 889 890 size = len + overhead; 891 msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype); 892 893 /* FIXME: need a timer or something to kick this so it can't 894 get stuck with no work outstanding and no buffer free */ 895 if (msg == NULL) { 896 skb_queue_tail(&dlci->skb_list, dlci->skb); 897 dlci->skb = NULL; 898 return -ENOMEM; 899 } 900 dp = msg->data; 901 902 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */ 903 /* Flag byte to carry the start/end info */ 904 *dp++ = last << 7 | first << 6 | 1; /* EA */ 905 len--; 906 } 907 memcpy(dp, dlci->skb->data, len); 908 skb_pull(dlci->skb, len); 909 __gsm_data_queue(dlci, msg); 910 if (last) { 911 dev_kfree_skb_any(dlci->skb); 912 dlci->skb = NULL; 913 } 914 return size; 915 } 916 917 /** 918 * gsm_dlci_data_sweep - look for data to send 919 * @gsm: the GSM mux 920 * 921 * Sweep the GSM mux channels in priority order looking for ones with 922 * data to send. We could do with optimising this scan a bit. We aim 923 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit 924 * TX_THRESH_LO we get called again 925 * 926 * FIXME: We should round robin between groups and in theory you can 927 * renegotiate DLCI priorities with optional stuff. Needs optimising. 928 */ 929 930 static void gsm_dlci_data_sweep(struct gsm_mux *gsm) 931 { 932 int len; 933 /* Priority ordering: We should do priority with RR of the groups */ 934 int i = 1; 935 936 while (i < NUM_DLCI) { 937 struct gsm_dlci *dlci; 938 939 if (gsm->tx_bytes > TX_THRESH_HI) 940 break; 941 dlci = gsm->dlci[i]; 942 if (dlci == NULL || dlci->constipated) { 943 i++; 944 continue; 945 } 946 if (dlci->adaption < 3 && !dlci->net) 947 len = gsm_dlci_data_output(gsm, dlci); 948 else 949 len = gsm_dlci_data_output_framed(gsm, dlci); 950 if (len < 0) 951 break; 952 /* DLCI empty - try the next */ 953 if (len == 0) 954 i++; 955 } 956 } 957 958 /** 959 * gsm_dlci_data_kick - transmit if possible 960 * @dlci: DLCI to kick 961 * 962 * Transmit data from this DLCI if the queue is empty. We can't rely on 963 * a tty wakeup except when we filled the pipe so we need to fire off 964 * new data ourselves in other cases. 965 */ 966 967 static void gsm_dlci_data_kick(struct gsm_dlci *dlci) 968 { 969 unsigned long flags; 970 int sweep; 971 972 if (dlci->constipated) 973 return; 974 975 spin_lock_irqsave(&dlci->gsm->tx_lock, flags); 976 /* If we have nothing running then we need to fire up */ 977 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO); 978 if (dlci->gsm->tx_bytes == 0) { 979 if (dlci->net) 980 gsm_dlci_data_output_framed(dlci->gsm, dlci); 981 else 982 gsm_dlci_data_output(dlci->gsm, dlci); 983 } 984 if (sweep) 985 gsm_dlci_data_sweep(dlci->gsm); 986 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); 987 } 988 989 /* 990 * Control message processing 991 */ 992 993 994 /** 995 * gsm_control_reply - send a response frame to a control 996 * @gsm: gsm channel 997 * @cmd: the command to use 998 * @data: data to follow encoded info 999 * @dlen: length of data 1000 * 1001 * Encode up and queue a UI/UIH frame containing our response. 1002 */ 1003 1004 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data, 1005 int dlen) 1006 { 1007 struct gsm_msg *msg; 1008 msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype); 1009 if (msg == NULL) 1010 return; 1011 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */ 1012 msg->data[1] = (dlen << 1) | EA; 1013 memcpy(msg->data + 2, data, dlen); 1014 gsm_data_queue(gsm->dlci[0], msg); 1015 } 1016 1017 /** 1018 * gsm_process_modem - process received modem status 1019 * @tty: virtual tty bound to the DLCI 1020 * @dlci: DLCI to affect 1021 * @modem: modem bits (full EA) 1022 * 1023 * Used when a modem control message or line state inline in adaption 1024 * layer 2 is processed. Sort out the local modem state and throttles 1025 */ 1026 1027 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci, 1028 u32 modem, int clen) 1029 { 1030 int mlines = 0; 1031 u8 brk = 0; 1032 int fc; 1033 1034 /* The modem status command can either contain one octet (v.24 signals) 1035 or two octets (v.24 signals + break signals). The length field will 1036 either be 2 or 3 respectively. This is specified in section 1037 5.4.6.3.7 of the 27.010 mux spec. */ 1038 1039 if (clen == 2) 1040 modem = modem & 0x7f; 1041 else { 1042 brk = modem & 0x7f; 1043 modem = (modem >> 7) & 0x7f; 1044 } 1045 1046 /* Flow control/ready to communicate */ 1047 fc = (modem & MDM_FC) || !(modem & MDM_RTR); 1048 if (fc && !dlci->constipated) { 1049 /* Need to throttle our output on this device */ 1050 dlci->constipated = 1; 1051 } else if (!fc && dlci->constipated) { 1052 dlci->constipated = 0; 1053 gsm_dlci_data_kick(dlci); 1054 } 1055 1056 /* Map modem bits */ 1057 if (modem & MDM_RTC) 1058 mlines |= TIOCM_DSR | TIOCM_DTR; 1059 if (modem & MDM_RTR) 1060 mlines |= TIOCM_RTS | TIOCM_CTS; 1061 if (modem & MDM_IC) 1062 mlines |= TIOCM_RI; 1063 if (modem & MDM_DV) 1064 mlines |= TIOCM_CD; 1065 1066 /* Carrier drop -> hangup */ 1067 if (tty) { 1068 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD)) 1069 if (!(tty->termios.c_cflag & CLOCAL)) 1070 tty_hangup(tty); 1071 } 1072 if (brk & 0x01) 1073 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK); 1074 dlci->modem_rx = mlines; 1075 } 1076 1077 /** 1078 * gsm_control_modem - modem status received 1079 * @gsm: GSM channel 1080 * @data: data following command 1081 * @clen: command length 1082 * 1083 * We have received a modem status control message. This is used by 1084 * the GSM mux protocol to pass virtual modem line status and optionally 1085 * to indicate break signals. Unpack it, convert to Linux representation 1086 * and if need be stuff a break message down the tty. 1087 */ 1088 1089 static void gsm_control_modem(struct gsm_mux *gsm, u8 *data, int clen) 1090 { 1091 unsigned int addr = 0; 1092 unsigned int modem = 0; 1093 struct gsm_dlci *dlci; 1094 int len = clen; 1095 u8 *dp = data; 1096 struct tty_struct *tty; 1097 1098 while (gsm_read_ea(&addr, *dp++) == 0) { 1099 len--; 1100 if (len == 0) 1101 return; 1102 } 1103 /* Must be at least one byte following the EA */ 1104 len--; 1105 if (len <= 0) 1106 return; 1107 1108 addr >>= 1; 1109 /* Closed port, or invalid ? */ 1110 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) 1111 return; 1112 dlci = gsm->dlci[addr]; 1113 1114 while (gsm_read_ea(&modem, *dp++) == 0) { 1115 len--; 1116 if (len == 0) 1117 return; 1118 } 1119 tty = tty_port_tty_get(&dlci->port); 1120 gsm_process_modem(tty, dlci, modem, clen); 1121 if (tty) { 1122 tty_wakeup(tty); 1123 tty_kref_put(tty); 1124 } 1125 gsm_control_reply(gsm, CMD_MSC, data, clen); 1126 } 1127 1128 /** 1129 * gsm_control_rls - remote line status 1130 * @gsm: GSM channel 1131 * @data: data bytes 1132 * @clen: data length 1133 * 1134 * The modem sends us a two byte message on the control channel whenever 1135 * it wishes to send us an error state from the virtual link. Stuff 1136 * this into the uplink tty if present 1137 */ 1138 1139 static void gsm_control_rls(struct gsm_mux *gsm, u8 *data, int clen) 1140 { 1141 struct tty_port *port; 1142 unsigned int addr = 0; 1143 u8 bits; 1144 int len = clen; 1145 u8 *dp = data; 1146 1147 while (gsm_read_ea(&addr, *dp++) == 0) { 1148 len--; 1149 if (len == 0) 1150 return; 1151 } 1152 /* Must be at least one byte following ea */ 1153 len--; 1154 if (len <= 0) 1155 return; 1156 addr >>= 1; 1157 /* Closed port, or invalid ? */ 1158 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) 1159 return; 1160 /* No error ? */ 1161 bits = *dp; 1162 if ((bits & 1) == 0) 1163 return; 1164 1165 port = &gsm->dlci[addr]->port; 1166 1167 if (bits & 2) 1168 tty_insert_flip_char(port, 0, TTY_OVERRUN); 1169 if (bits & 4) 1170 tty_insert_flip_char(port, 0, TTY_PARITY); 1171 if (bits & 8) 1172 tty_insert_flip_char(port, 0, TTY_FRAME); 1173 1174 tty_flip_buffer_push(port); 1175 1176 gsm_control_reply(gsm, CMD_RLS, data, clen); 1177 } 1178 1179 static void gsm_dlci_begin_close(struct gsm_dlci *dlci); 1180 1181 /** 1182 * gsm_control_message - DLCI 0 control processing 1183 * @gsm: our GSM mux 1184 * @command: the command EA 1185 * @data: data beyond the command/length EAs 1186 * @clen: length 1187 * 1188 * Input processor for control messages from the other end of the link. 1189 * Processes the incoming request and queues a response frame or an 1190 * NSC response if not supported 1191 */ 1192 1193 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, 1194 u8 *data, int clen) 1195 { 1196 u8 buf[1]; 1197 unsigned long flags; 1198 1199 switch (command) { 1200 case CMD_CLD: { 1201 struct gsm_dlci *dlci = gsm->dlci[0]; 1202 /* Modem wishes to close down */ 1203 if (dlci) { 1204 dlci->dead = 1; 1205 gsm->dead = 1; 1206 gsm_dlci_begin_close(dlci); 1207 } 1208 } 1209 break; 1210 case CMD_TEST: 1211 /* Modem wishes to test, reply with the data */ 1212 gsm_control_reply(gsm, CMD_TEST, data, clen); 1213 break; 1214 case CMD_FCON: 1215 /* Modem can accept data again */ 1216 gsm->constipated = 0; 1217 gsm_control_reply(gsm, CMD_FCON, NULL, 0); 1218 /* Kick the link in case it is idling */ 1219 spin_lock_irqsave(&gsm->tx_lock, flags); 1220 gsm_data_kick(gsm); 1221 spin_unlock_irqrestore(&gsm->tx_lock, flags); 1222 break; 1223 case CMD_FCOFF: 1224 /* Modem wants us to STFU */ 1225 gsm->constipated = 1; 1226 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0); 1227 break; 1228 case CMD_MSC: 1229 /* Out of band modem line change indicator for a DLCI */ 1230 gsm_control_modem(gsm, data, clen); 1231 break; 1232 case CMD_RLS: 1233 /* Out of band error reception for a DLCI */ 1234 gsm_control_rls(gsm, data, clen); 1235 break; 1236 case CMD_PSC: 1237 /* Modem wishes to enter power saving state */ 1238 gsm_control_reply(gsm, CMD_PSC, NULL, 0); 1239 break; 1240 /* Optional unsupported commands */ 1241 case CMD_PN: /* Parameter negotiation */ 1242 case CMD_RPN: /* Remote port negotiation */ 1243 case CMD_SNC: /* Service negotiation command */ 1244 default: 1245 /* Reply to bad commands with an NSC */ 1246 buf[0] = command; 1247 gsm_control_reply(gsm, CMD_NSC, buf, 1); 1248 break; 1249 } 1250 } 1251 1252 /** 1253 * gsm_control_response - process a response to our control 1254 * @gsm: our GSM mux 1255 * @command: the command (response) EA 1256 * @data: data beyond the command/length EA 1257 * @clen: length 1258 * 1259 * Process a response to an outstanding command. We only allow a single 1260 * control message in flight so this is fairly easy. All the clean up 1261 * is done by the caller, we just update the fields, flag it as done 1262 * and return 1263 */ 1264 1265 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command, 1266 u8 *data, int clen) 1267 { 1268 struct gsm_control *ctrl; 1269 unsigned long flags; 1270 1271 spin_lock_irqsave(&gsm->control_lock, flags); 1272 1273 ctrl = gsm->pending_cmd; 1274 /* Does the reply match our command */ 1275 command |= 1; 1276 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) { 1277 /* Our command was replied to, kill the retry timer */ 1278 del_timer(&gsm->t2_timer); 1279 gsm->pending_cmd = NULL; 1280 /* Rejected by the other end */ 1281 if (command == CMD_NSC) 1282 ctrl->error = -EOPNOTSUPP; 1283 ctrl->done = 1; 1284 wake_up(&gsm->event); 1285 } 1286 spin_unlock_irqrestore(&gsm->control_lock, flags); 1287 } 1288 1289 /** 1290 * gsm_control_transmit - send control packet 1291 * @gsm: gsm mux 1292 * @ctrl: frame to send 1293 * 1294 * Send out a pending control command (called under control lock) 1295 */ 1296 1297 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl) 1298 { 1299 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype); 1300 if (msg == NULL) 1301 return; 1302 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */ 1303 memcpy(msg->data + 1, ctrl->data, ctrl->len); 1304 gsm_data_queue(gsm->dlci[0], msg); 1305 } 1306 1307 /** 1308 * gsm_control_retransmit - retransmit a control frame 1309 * @data: pointer to our gsm object 1310 * 1311 * Called off the T2 timer expiry in order to retransmit control frames 1312 * that have been lost in the system somewhere. The control_lock protects 1313 * us from colliding with another sender or a receive completion event. 1314 * In that situation the timer may still occur in a small window but 1315 * gsm->pending_cmd will be NULL and we just let the timer expire. 1316 */ 1317 1318 static void gsm_control_retransmit(unsigned long data) 1319 { 1320 struct gsm_mux *gsm = (struct gsm_mux *)data; 1321 struct gsm_control *ctrl; 1322 unsigned long flags; 1323 spin_lock_irqsave(&gsm->control_lock, flags); 1324 ctrl = gsm->pending_cmd; 1325 if (ctrl) { 1326 gsm->cretries--; 1327 if (gsm->cretries == 0) { 1328 gsm->pending_cmd = NULL; 1329 ctrl->error = -ETIMEDOUT; 1330 ctrl->done = 1; 1331 spin_unlock_irqrestore(&gsm->control_lock, flags); 1332 wake_up(&gsm->event); 1333 return; 1334 } 1335 gsm_control_transmit(gsm, ctrl); 1336 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); 1337 } 1338 spin_unlock_irqrestore(&gsm->control_lock, flags); 1339 } 1340 1341 /** 1342 * gsm_control_send - send a control frame on DLCI 0 1343 * @gsm: the GSM channel 1344 * @command: command to send including CR bit 1345 * @data: bytes of data (must be kmalloced) 1346 * @len: length of the block to send 1347 * 1348 * Queue and dispatch a control command. Only one command can be 1349 * active at a time. In theory more can be outstanding but the matching 1350 * gets really complicated so for now stick to one outstanding. 1351 */ 1352 1353 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm, 1354 unsigned int command, u8 *data, int clen) 1355 { 1356 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control), 1357 GFP_KERNEL); 1358 unsigned long flags; 1359 if (ctrl == NULL) 1360 return NULL; 1361 retry: 1362 wait_event(gsm->event, gsm->pending_cmd == NULL); 1363 spin_lock_irqsave(&gsm->control_lock, flags); 1364 if (gsm->pending_cmd != NULL) { 1365 spin_unlock_irqrestore(&gsm->control_lock, flags); 1366 goto retry; 1367 } 1368 ctrl->cmd = command; 1369 ctrl->data = data; 1370 ctrl->len = clen; 1371 gsm->pending_cmd = ctrl; 1372 gsm->cretries = gsm->n2; 1373 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); 1374 gsm_control_transmit(gsm, ctrl); 1375 spin_unlock_irqrestore(&gsm->control_lock, flags); 1376 return ctrl; 1377 } 1378 1379 /** 1380 * gsm_control_wait - wait for a control to finish 1381 * @gsm: GSM mux 1382 * @control: control we are waiting on 1383 * 1384 * Waits for the control to complete or time out. Frees any used 1385 * resources and returns 0 for success, or an error if the remote 1386 * rejected or ignored the request. 1387 */ 1388 1389 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control) 1390 { 1391 int err; 1392 wait_event(gsm->event, control->done == 1); 1393 err = control->error; 1394 kfree(control); 1395 return err; 1396 } 1397 1398 1399 /* 1400 * DLCI level handling: Needs krefs 1401 */ 1402 1403 /* 1404 * State transitions and timers 1405 */ 1406 1407 /** 1408 * gsm_dlci_close - a DLCI has closed 1409 * @dlci: DLCI that closed 1410 * 1411 * Perform processing when moving a DLCI into closed state. If there 1412 * is an attached tty this is hung up 1413 */ 1414 1415 static void gsm_dlci_close(struct gsm_dlci *dlci) 1416 { 1417 del_timer(&dlci->t1); 1418 if (debug & 8) 1419 pr_debug("DLCI %d goes closed.\n", dlci->addr); 1420 dlci->state = DLCI_CLOSED; 1421 if (dlci->addr != 0) { 1422 tty_port_tty_hangup(&dlci->port, false); 1423 kfifo_reset(dlci->fifo); 1424 } else 1425 dlci->gsm->dead = 1; 1426 wake_up(&dlci->gsm->event); 1427 /* A DLCI 0 close is a MUX termination so we need to kick that 1428 back to userspace somehow */ 1429 } 1430 1431 /** 1432 * gsm_dlci_open - a DLCI has opened 1433 * @dlci: DLCI that opened 1434 * 1435 * Perform processing when moving a DLCI into open state. 1436 */ 1437 1438 static void gsm_dlci_open(struct gsm_dlci *dlci) 1439 { 1440 /* Note that SABM UA .. SABM UA first UA lost can mean that we go 1441 open -> open */ 1442 del_timer(&dlci->t1); 1443 /* This will let a tty open continue */ 1444 dlci->state = DLCI_OPEN; 1445 if (debug & 8) 1446 pr_debug("DLCI %d goes open.\n", dlci->addr); 1447 wake_up(&dlci->gsm->event); 1448 } 1449 1450 /** 1451 * gsm_dlci_t1 - T1 timer expiry 1452 * @dlci: DLCI that opened 1453 * 1454 * The T1 timer handles retransmits of control frames (essentially of 1455 * SABM and DISC). We resend the command until the retry count runs out 1456 * in which case an opening port goes back to closed and a closing port 1457 * is simply put into closed state (any further frames from the other 1458 * end will get a DM response) 1459 */ 1460 1461 static void gsm_dlci_t1(unsigned long data) 1462 { 1463 struct gsm_dlci *dlci = (struct gsm_dlci *)data; 1464 struct gsm_mux *gsm = dlci->gsm; 1465 1466 switch (dlci->state) { 1467 case DLCI_OPENING: 1468 dlci->retries--; 1469 if (dlci->retries) { 1470 gsm_command(dlci->gsm, dlci->addr, SABM|PF); 1471 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1472 } else 1473 gsm_dlci_close(dlci); 1474 break; 1475 case DLCI_CLOSING: 1476 dlci->retries--; 1477 if (dlci->retries) { 1478 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 1479 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1480 } else 1481 gsm_dlci_close(dlci); 1482 break; 1483 } 1484 } 1485 1486 /** 1487 * gsm_dlci_begin_open - start channel open procedure 1488 * @dlci: DLCI to open 1489 * 1490 * Commence opening a DLCI from the Linux side. We issue SABM messages 1491 * to the modem which should then reply with a UA, at which point we 1492 * will move into open state. Opening is done asynchronously with retry 1493 * running off timers and the responses. 1494 */ 1495 1496 static void gsm_dlci_begin_open(struct gsm_dlci *dlci) 1497 { 1498 struct gsm_mux *gsm = dlci->gsm; 1499 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING) 1500 return; 1501 dlci->retries = gsm->n2; 1502 dlci->state = DLCI_OPENING; 1503 gsm_command(dlci->gsm, dlci->addr, SABM|PF); 1504 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1505 } 1506 1507 /** 1508 * gsm_dlci_begin_close - start channel open procedure 1509 * @dlci: DLCI to open 1510 * 1511 * Commence closing a DLCI from the Linux side. We issue DISC messages 1512 * to the modem which should then reply with a UA, at which point we 1513 * will move into closed state. Closing is done asynchronously with retry 1514 * off timers. We may also receive a DM reply from the other end which 1515 * indicates the channel was already closed. 1516 */ 1517 1518 static void gsm_dlci_begin_close(struct gsm_dlci *dlci) 1519 { 1520 struct gsm_mux *gsm = dlci->gsm; 1521 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING) 1522 return; 1523 dlci->retries = gsm->n2; 1524 dlci->state = DLCI_CLOSING; 1525 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 1526 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1527 } 1528 1529 /** 1530 * gsm_dlci_data - data arrived 1531 * @dlci: channel 1532 * @data: block of bytes received 1533 * @len: length of received block 1534 * 1535 * A UI or UIH frame has arrived which contains data for a channel 1536 * other than the control channel. If the relevant virtual tty is 1537 * open we shovel the bits down it, if not we drop them. 1538 */ 1539 1540 static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen) 1541 { 1542 /* krefs .. */ 1543 struct tty_port *port = &dlci->port; 1544 struct tty_struct *tty; 1545 unsigned int modem = 0; 1546 int len = clen; 1547 1548 if (debug & 16) 1549 pr_debug("%d bytes for tty\n", len); 1550 switch (dlci->adaption) { 1551 /* Unsupported types */ 1552 /* Packetised interruptible data */ 1553 case 4: 1554 break; 1555 /* Packetised uininterruptible voice/data */ 1556 case 3: 1557 break; 1558 /* Asynchronous serial with line state in each frame */ 1559 case 2: 1560 while (gsm_read_ea(&modem, *data++) == 0) { 1561 len--; 1562 if (len == 0) 1563 return; 1564 } 1565 tty = tty_port_tty_get(port); 1566 if (tty) { 1567 gsm_process_modem(tty, dlci, modem, clen); 1568 tty_kref_put(tty); 1569 } 1570 /* Line state will go via DLCI 0 controls only */ 1571 case 1: 1572 default: 1573 tty_insert_flip_string(port, data, len); 1574 tty_flip_buffer_push(port); 1575 } 1576 } 1577 1578 /** 1579 * gsm_dlci_control - data arrived on control channel 1580 * @dlci: channel 1581 * @data: block of bytes received 1582 * @len: length of received block 1583 * 1584 * A UI or UIH frame has arrived which contains data for DLCI 0 the 1585 * control channel. This should contain a command EA followed by 1586 * control data bytes. The command EA contains a command/response bit 1587 * and we divide up the work accordingly. 1588 */ 1589 1590 static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len) 1591 { 1592 /* See what command is involved */ 1593 unsigned int command = 0; 1594 while (len-- > 0) { 1595 if (gsm_read_ea(&command, *data++) == 1) { 1596 int clen = *data++; 1597 len--; 1598 /* FIXME: this is properly an EA */ 1599 clen >>= 1; 1600 /* Malformed command ? */ 1601 if (clen > len) 1602 return; 1603 if (command & 1) 1604 gsm_control_message(dlci->gsm, command, 1605 data, clen); 1606 else 1607 gsm_control_response(dlci->gsm, command, 1608 data, clen); 1609 return; 1610 } 1611 } 1612 } 1613 1614 /* 1615 * Allocate/Free DLCI channels 1616 */ 1617 1618 /** 1619 * gsm_dlci_alloc - allocate a DLCI 1620 * @gsm: GSM mux 1621 * @addr: address of the DLCI 1622 * 1623 * Allocate and install a new DLCI object into the GSM mux. 1624 * 1625 * FIXME: review locking races 1626 */ 1627 1628 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr) 1629 { 1630 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC); 1631 if (dlci == NULL) 1632 return NULL; 1633 spin_lock_init(&dlci->lock); 1634 mutex_init(&dlci->mutex); 1635 dlci->fifo = &dlci->_fifo; 1636 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) { 1637 kfree(dlci); 1638 return NULL; 1639 } 1640 1641 skb_queue_head_init(&dlci->skb_list); 1642 init_timer(&dlci->t1); 1643 dlci->t1.function = gsm_dlci_t1; 1644 dlci->t1.data = (unsigned long)dlci; 1645 tty_port_init(&dlci->port); 1646 dlci->port.ops = &gsm_port_ops; 1647 dlci->gsm = gsm; 1648 dlci->addr = addr; 1649 dlci->adaption = gsm->adaption; 1650 dlci->state = DLCI_CLOSED; 1651 if (addr) 1652 dlci->data = gsm_dlci_data; 1653 else 1654 dlci->data = gsm_dlci_command; 1655 gsm->dlci[addr] = dlci; 1656 return dlci; 1657 } 1658 1659 /** 1660 * gsm_dlci_free - free DLCI 1661 * @dlci: DLCI to free 1662 * 1663 * Free up a DLCI. 1664 * 1665 * Can sleep. 1666 */ 1667 static void gsm_dlci_free(struct tty_port *port) 1668 { 1669 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 1670 1671 del_timer_sync(&dlci->t1); 1672 dlci->gsm->dlci[dlci->addr] = NULL; 1673 kfifo_free(dlci->fifo); 1674 while ((dlci->skb = skb_dequeue(&dlci->skb_list))) 1675 dev_kfree_skb(dlci->skb); 1676 kfree(dlci); 1677 } 1678 1679 static inline void dlci_get(struct gsm_dlci *dlci) 1680 { 1681 tty_port_get(&dlci->port); 1682 } 1683 1684 static inline void dlci_put(struct gsm_dlci *dlci) 1685 { 1686 tty_port_put(&dlci->port); 1687 } 1688 1689 static void gsm_destroy_network(struct gsm_dlci *dlci); 1690 1691 /** 1692 * gsm_dlci_release - release DLCI 1693 * @dlci: DLCI to destroy 1694 * 1695 * Release a DLCI. Actual free is deferred until either 1696 * mux is closed or tty is closed - whichever is last. 1697 * 1698 * Can sleep. 1699 */ 1700 static void gsm_dlci_release(struct gsm_dlci *dlci) 1701 { 1702 struct tty_struct *tty = tty_port_tty_get(&dlci->port); 1703 if (tty) { 1704 mutex_lock(&dlci->mutex); 1705 gsm_destroy_network(dlci); 1706 mutex_unlock(&dlci->mutex); 1707 1708 tty_vhangup(tty); 1709 1710 tty_port_tty_set(&dlci->port, NULL); 1711 tty_kref_put(tty); 1712 } 1713 dlci->state = DLCI_CLOSED; 1714 dlci_put(dlci); 1715 } 1716 1717 /* 1718 * LAPBish link layer logic 1719 */ 1720 1721 /** 1722 * gsm_queue - a GSM frame is ready to process 1723 * @gsm: pointer to our gsm mux 1724 * 1725 * At this point in time a frame has arrived and been demangled from 1726 * the line encoding. All the differences between the encodings have 1727 * been handled below us and the frame is unpacked into the structures. 1728 * The fcs holds the header FCS but any data FCS must be added here. 1729 */ 1730 1731 static void gsm_queue(struct gsm_mux *gsm) 1732 { 1733 struct gsm_dlci *dlci; 1734 u8 cr; 1735 int address; 1736 /* We have to sneak a look at the packet body to do the FCS. 1737 A somewhat layering violation in the spec */ 1738 1739 if ((gsm->control & ~PF) == UI) 1740 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len); 1741 if (gsm->encoding == 0) { 1742 /* WARNING: gsm->received_fcs is used for 1743 gsm->encoding = 0 only. 1744 In this case it contain the last piece of data 1745 required to generate final CRC */ 1746 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs); 1747 } 1748 if (gsm->fcs != GOOD_FCS) { 1749 gsm->bad_fcs++; 1750 if (debug & 4) 1751 pr_debug("BAD FCS %02x\n", gsm->fcs); 1752 return; 1753 } 1754 address = gsm->address >> 1; 1755 if (address >= NUM_DLCI) 1756 goto invalid; 1757 1758 cr = gsm->address & 1; /* C/R bit */ 1759 1760 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len); 1761 1762 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */ 1763 dlci = gsm->dlci[address]; 1764 1765 switch (gsm->control) { 1766 case SABM|PF: 1767 if (cr == 0) 1768 goto invalid; 1769 if (dlci == NULL) 1770 dlci = gsm_dlci_alloc(gsm, address); 1771 if (dlci == NULL) 1772 return; 1773 if (dlci->dead) 1774 gsm_response(gsm, address, DM); 1775 else { 1776 gsm_response(gsm, address, UA); 1777 gsm_dlci_open(dlci); 1778 } 1779 break; 1780 case DISC|PF: 1781 if (cr == 0) 1782 goto invalid; 1783 if (dlci == NULL || dlci->state == DLCI_CLOSED) { 1784 gsm_response(gsm, address, DM); 1785 return; 1786 } 1787 /* Real close complete */ 1788 gsm_response(gsm, address, UA); 1789 gsm_dlci_close(dlci); 1790 break; 1791 case UA: 1792 case UA|PF: 1793 if (cr == 0 || dlci == NULL) 1794 break; 1795 switch (dlci->state) { 1796 case DLCI_CLOSING: 1797 gsm_dlci_close(dlci); 1798 break; 1799 case DLCI_OPENING: 1800 gsm_dlci_open(dlci); 1801 break; 1802 } 1803 break; 1804 case DM: /* DM can be valid unsolicited */ 1805 case DM|PF: 1806 if (cr) 1807 goto invalid; 1808 if (dlci == NULL) 1809 return; 1810 gsm_dlci_close(dlci); 1811 break; 1812 case UI: 1813 case UI|PF: 1814 case UIH: 1815 case UIH|PF: 1816 #if 0 1817 if (cr) 1818 goto invalid; 1819 #endif 1820 if (dlci == NULL || dlci->state != DLCI_OPEN) { 1821 gsm_command(gsm, address, DM|PF); 1822 return; 1823 } 1824 dlci->data(dlci, gsm->buf, gsm->len); 1825 break; 1826 default: 1827 goto invalid; 1828 } 1829 return; 1830 invalid: 1831 gsm->malformed++; 1832 return; 1833 } 1834 1835 1836 /** 1837 * gsm0_receive - perform processing for non-transparency 1838 * @gsm: gsm data for this ldisc instance 1839 * @c: character 1840 * 1841 * Receive bytes in gsm mode 0 1842 */ 1843 1844 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) 1845 { 1846 unsigned int len; 1847 1848 switch (gsm->state) { 1849 case GSM_SEARCH: /* SOF marker */ 1850 if (c == GSM0_SOF) { 1851 gsm->state = GSM_ADDRESS; 1852 gsm->address = 0; 1853 gsm->len = 0; 1854 gsm->fcs = INIT_FCS; 1855 } 1856 break; 1857 case GSM_ADDRESS: /* Address EA */ 1858 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1859 if (gsm_read_ea(&gsm->address, c)) 1860 gsm->state = GSM_CONTROL; 1861 break; 1862 case GSM_CONTROL: /* Control Byte */ 1863 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1864 gsm->control = c; 1865 gsm->state = GSM_LEN0; 1866 break; 1867 case GSM_LEN0: /* Length EA */ 1868 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1869 if (gsm_read_ea(&gsm->len, c)) { 1870 if (gsm->len > gsm->mru) { 1871 gsm->bad_size++; 1872 gsm->state = GSM_SEARCH; 1873 break; 1874 } 1875 gsm->count = 0; 1876 if (!gsm->len) 1877 gsm->state = GSM_FCS; 1878 else 1879 gsm->state = GSM_DATA; 1880 break; 1881 } 1882 gsm->state = GSM_LEN1; 1883 break; 1884 case GSM_LEN1: 1885 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1886 len = c; 1887 gsm->len |= len << 7; 1888 if (gsm->len > gsm->mru) { 1889 gsm->bad_size++; 1890 gsm->state = GSM_SEARCH; 1891 break; 1892 } 1893 gsm->count = 0; 1894 if (!gsm->len) 1895 gsm->state = GSM_FCS; 1896 else 1897 gsm->state = GSM_DATA; 1898 break; 1899 case GSM_DATA: /* Data */ 1900 gsm->buf[gsm->count++] = c; 1901 if (gsm->count == gsm->len) 1902 gsm->state = GSM_FCS; 1903 break; 1904 case GSM_FCS: /* FCS follows the packet */ 1905 gsm->received_fcs = c; 1906 gsm_queue(gsm); 1907 gsm->state = GSM_SSOF; 1908 break; 1909 case GSM_SSOF: 1910 if (c == GSM0_SOF) { 1911 gsm->state = GSM_SEARCH; 1912 break; 1913 } 1914 break; 1915 } 1916 } 1917 1918 /** 1919 * gsm1_receive - perform processing for non-transparency 1920 * @gsm: gsm data for this ldisc instance 1921 * @c: character 1922 * 1923 * Receive bytes in mode 1 (Advanced option) 1924 */ 1925 1926 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c) 1927 { 1928 if (c == GSM1_SOF) { 1929 /* EOF is only valid in frame if we have got to the data state 1930 and received at least one byte (the FCS) */ 1931 if (gsm->state == GSM_DATA && gsm->count) { 1932 /* Extract the FCS */ 1933 gsm->count--; 1934 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]); 1935 gsm->len = gsm->count; 1936 gsm_queue(gsm); 1937 gsm->state = GSM_START; 1938 return; 1939 } 1940 /* Any partial frame was a runt so go back to start */ 1941 if (gsm->state != GSM_START) { 1942 gsm->malformed++; 1943 gsm->state = GSM_START; 1944 } 1945 /* A SOF in GSM_START means we are still reading idling or 1946 framing bytes */ 1947 return; 1948 } 1949 1950 if (c == GSM1_ESCAPE) { 1951 gsm->escape = 1; 1952 return; 1953 } 1954 1955 /* Only an unescaped SOF gets us out of GSM search */ 1956 if (gsm->state == GSM_SEARCH) 1957 return; 1958 1959 if (gsm->escape) { 1960 c ^= GSM1_ESCAPE_BITS; 1961 gsm->escape = 0; 1962 } 1963 switch (gsm->state) { 1964 case GSM_START: /* First byte after SOF */ 1965 gsm->address = 0; 1966 gsm->state = GSM_ADDRESS; 1967 gsm->fcs = INIT_FCS; 1968 /* Drop through */ 1969 case GSM_ADDRESS: /* Address continuation */ 1970 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1971 if (gsm_read_ea(&gsm->address, c)) 1972 gsm->state = GSM_CONTROL; 1973 break; 1974 case GSM_CONTROL: /* Control Byte */ 1975 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1976 gsm->control = c; 1977 gsm->count = 0; 1978 gsm->state = GSM_DATA; 1979 break; 1980 case GSM_DATA: /* Data */ 1981 if (gsm->count > gsm->mru) { /* Allow one for the FCS */ 1982 gsm->state = GSM_OVERRUN; 1983 gsm->bad_size++; 1984 } else 1985 gsm->buf[gsm->count++] = c; 1986 break; 1987 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */ 1988 break; 1989 } 1990 } 1991 1992 /** 1993 * gsm_error - handle tty error 1994 * @gsm: ldisc data 1995 * @data: byte received (may be invalid) 1996 * @flag: error received 1997 * 1998 * Handle an error in the receipt of data for a frame. Currently we just 1999 * go back to hunting for a SOF. 2000 * 2001 * FIXME: better diagnostics ? 2002 */ 2003 2004 static void gsm_error(struct gsm_mux *gsm, 2005 unsigned char data, unsigned char flag) 2006 { 2007 gsm->state = GSM_SEARCH; 2008 gsm->io_error++; 2009 } 2010 2011 /** 2012 * gsm_cleanup_mux - generic GSM protocol cleanup 2013 * @gsm: our mux 2014 * 2015 * Clean up the bits of the mux which are the same for all framing 2016 * protocols. Remove the mux from the mux table, stop all the timers 2017 * and then shut down each device hanging up the channels as we go. 2018 */ 2019 2020 static void gsm_cleanup_mux(struct gsm_mux *gsm) 2021 { 2022 int i; 2023 struct gsm_dlci *dlci = gsm->dlci[0]; 2024 struct gsm_msg *txq, *ntxq; 2025 struct gsm_control *gc; 2026 2027 gsm->dead = 1; 2028 2029 spin_lock(&gsm_mux_lock); 2030 for (i = 0; i < MAX_MUX; i++) { 2031 if (gsm_mux[i] == gsm) { 2032 gsm_mux[i] = NULL; 2033 break; 2034 } 2035 } 2036 spin_unlock(&gsm_mux_lock); 2037 WARN_ON(i == MAX_MUX); 2038 2039 /* In theory disconnecting DLCI 0 is sufficient but for some 2040 modems this is apparently not the case. */ 2041 if (dlci) { 2042 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0); 2043 if (gc) 2044 gsm_control_wait(gsm, gc); 2045 } 2046 del_timer_sync(&gsm->t2_timer); 2047 /* Now we are sure T2 has stopped */ 2048 if (dlci) { 2049 dlci->dead = 1; 2050 gsm_dlci_begin_close(dlci); 2051 wait_event_interruptible(gsm->event, 2052 dlci->state == DLCI_CLOSED); 2053 } 2054 /* Free up any link layer users */ 2055 mutex_lock(&gsm->mutex); 2056 for (i = 0; i < NUM_DLCI; i++) 2057 if (gsm->dlci[i]) 2058 gsm_dlci_release(gsm->dlci[i]); 2059 mutex_unlock(&gsm->mutex); 2060 /* Now wipe the queues */ 2061 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list) 2062 kfree(txq); 2063 INIT_LIST_HEAD(&gsm->tx_list); 2064 } 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 static 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 2112 /** 2113 * gsm_free_mux - free up a mux 2114 * @mux: mux to free 2115 * 2116 * Dispose of allocated resources for a dead mux 2117 */ 2118 static void gsm_free_mux(struct gsm_mux *gsm) 2119 { 2120 kfree(gsm->txframe); 2121 kfree(gsm->buf); 2122 kfree(gsm); 2123 } 2124 2125 /** 2126 * gsm_free_muxr - free up a mux 2127 * @mux: mux to free 2128 * 2129 * Dispose of allocated resources for a dead mux 2130 */ 2131 static void gsm_free_muxr(struct kref *ref) 2132 { 2133 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref); 2134 gsm_free_mux(gsm); 2135 } 2136 2137 static inline void mux_get(struct gsm_mux *gsm) 2138 { 2139 kref_get(&gsm->ref); 2140 } 2141 2142 static inline void mux_put(struct gsm_mux *gsm) 2143 { 2144 kref_put(&gsm->ref, gsm_free_muxr); 2145 } 2146 2147 /** 2148 * gsm_alloc_mux - allocate a mux 2149 * 2150 * Creates a new mux ready for activation. 2151 */ 2152 2153 static struct gsm_mux *gsm_alloc_mux(void) 2154 { 2155 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL); 2156 if (gsm == NULL) 2157 return NULL; 2158 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL); 2159 if (gsm->buf == NULL) { 2160 kfree(gsm); 2161 return NULL; 2162 } 2163 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL); 2164 if (gsm->txframe == NULL) { 2165 kfree(gsm->buf); 2166 kfree(gsm); 2167 return NULL; 2168 } 2169 spin_lock_init(&gsm->lock); 2170 mutex_init(&gsm->mutex); 2171 kref_init(&gsm->ref); 2172 INIT_LIST_HEAD(&gsm->tx_list); 2173 2174 gsm->t1 = T1; 2175 gsm->t2 = T2; 2176 gsm->n2 = N2; 2177 gsm->ftype = UIH; 2178 gsm->adaption = 1; 2179 gsm->encoding = 1; 2180 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */ 2181 gsm->mtu = 64; 2182 gsm->dead = 1; /* Avoid early tty opens */ 2183 2184 return gsm; 2185 } 2186 2187 /** 2188 * gsmld_output - write to link 2189 * @gsm: our mux 2190 * @data: bytes to output 2191 * @len: size 2192 * 2193 * Write a block of data from the GSM mux to the data channel. This 2194 * will eventually be serialized from above but at the moment isn't. 2195 */ 2196 2197 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len) 2198 { 2199 if (tty_write_room(gsm->tty) < len) { 2200 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags); 2201 return -ENOSPC; 2202 } 2203 if (debug & 4) 2204 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET, 2205 data, len); 2206 gsm->tty->ops->write(gsm->tty, data, len); 2207 return len; 2208 } 2209 2210 /** 2211 * gsmld_attach_gsm - mode set up 2212 * @tty: our tty structure 2213 * @gsm: our mux 2214 * 2215 * Set up the MUX for basic mode and commence connecting to the 2216 * modem. Currently called from the line discipline set up but 2217 * will need moving to an ioctl path. 2218 */ 2219 2220 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 2221 { 2222 int ret, i; 2223 int base = gsm->num << 6; /* Base for this MUX */ 2224 2225 gsm->tty = tty_kref_get(tty); 2226 gsm->output = gsmld_output; 2227 ret = gsm_activate_mux(gsm); 2228 if (ret != 0) 2229 tty_kref_put(gsm->tty); 2230 else { 2231 /* Don't register device 0 - this is the control channel and not 2232 a usable tty interface */ 2233 for (i = 1; i < NUM_DLCI; i++) 2234 tty_register_device(gsm_tty_driver, base + i, NULL); 2235 } 2236 return ret; 2237 } 2238 2239 2240 /** 2241 * gsmld_detach_gsm - stop doing 0710 mux 2242 * @tty: tty attached to the mux 2243 * @gsm: mux 2244 * 2245 * Shutdown and then clean up the resources used by the line discipline 2246 */ 2247 2248 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 2249 { 2250 int i; 2251 int base = gsm->num << 6; /* Base for this MUX */ 2252 2253 WARN_ON(tty != gsm->tty); 2254 for (i = 1; i < NUM_DLCI; i++) 2255 tty_unregister_device(gsm_tty_driver, base + i); 2256 gsm_cleanup_mux(gsm); 2257 tty_kref_put(gsm->tty); 2258 gsm->tty = NULL; 2259 } 2260 2261 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, 2262 char *fp, int count) 2263 { 2264 struct gsm_mux *gsm = tty->disc_data; 2265 const unsigned char *dp; 2266 char *f; 2267 int i; 2268 char buf[64]; 2269 char flags = TTY_NORMAL; 2270 2271 if (debug & 4) 2272 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET, 2273 cp, count); 2274 2275 for (i = count, dp = cp, f = fp; i; i--, dp++) { 2276 if (f) 2277 flags = *f++; 2278 switch (flags) { 2279 case TTY_NORMAL: 2280 gsm->receive(gsm, *dp); 2281 break; 2282 case TTY_OVERRUN: 2283 case TTY_BREAK: 2284 case TTY_PARITY: 2285 case TTY_FRAME: 2286 gsm->error(gsm, *dp, flags); 2287 break; 2288 default: 2289 WARN_ONCE(1, "%s: unknown flag %d\n", 2290 tty_name(tty, buf), flags); 2291 break; 2292 } 2293 } 2294 /* FASYNC if needed ? */ 2295 /* If clogged call tty_throttle(tty); */ 2296 } 2297 2298 /** 2299 * gsmld_chars_in_buffer - report available bytes 2300 * @tty: tty device 2301 * 2302 * Report the number of characters buffered to be delivered to user 2303 * at this instant in time. 2304 * 2305 * Locking: gsm lock 2306 */ 2307 2308 static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty) 2309 { 2310 return 0; 2311 } 2312 2313 /** 2314 * gsmld_flush_buffer - clean input queue 2315 * @tty: terminal device 2316 * 2317 * Flush the input buffer. Called when the line discipline is 2318 * being closed, when the tty layer wants the buffer flushed (eg 2319 * at hangup). 2320 */ 2321 2322 static void gsmld_flush_buffer(struct tty_struct *tty) 2323 { 2324 } 2325 2326 /** 2327 * gsmld_close - close the ldisc for this tty 2328 * @tty: device 2329 * 2330 * Called from the terminal layer when this line discipline is 2331 * being shut down, either because of a close or becsuse of a 2332 * discipline change. The function will not be called while other 2333 * ldisc methods are in progress. 2334 */ 2335 2336 static void gsmld_close(struct tty_struct *tty) 2337 { 2338 struct gsm_mux *gsm = tty->disc_data; 2339 2340 gsmld_detach_gsm(tty, gsm); 2341 2342 gsmld_flush_buffer(tty); 2343 /* Do other clean up here */ 2344 mux_put(gsm); 2345 } 2346 2347 /** 2348 * gsmld_open - open an ldisc 2349 * @tty: terminal to open 2350 * 2351 * Called when this line discipline is being attached to the 2352 * terminal device. Can sleep. Called serialized so that no 2353 * other events will occur in parallel. No further open will occur 2354 * until a close. 2355 */ 2356 2357 static int gsmld_open(struct tty_struct *tty) 2358 { 2359 struct gsm_mux *gsm; 2360 2361 if (tty->ops->write == NULL) 2362 return -EINVAL; 2363 2364 /* Attach our ldisc data */ 2365 gsm = gsm_alloc_mux(); 2366 if (gsm == NULL) 2367 return -ENOMEM; 2368 2369 tty->disc_data = gsm; 2370 tty->receive_room = 65536; 2371 2372 /* Attach the initial passive connection */ 2373 gsm->encoding = 1; 2374 return gsmld_attach_gsm(tty, gsm); 2375 } 2376 2377 /** 2378 * gsmld_write_wakeup - asynchronous I/O notifier 2379 * @tty: tty device 2380 * 2381 * Required for the ptys, serial driver etc. since processes 2382 * that attach themselves to the master and rely on ASYNC 2383 * IO must be woken up 2384 */ 2385 2386 static void gsmld_write_wakeup(struct tty_struct *tty) 2387 { 2388 struct gsm_mux *gsm = tty->disc_data; 2389 unsigned long flags; 2390 2391 /* Queue poll */ 2392 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 2393 spin_lock_irqsave(&gsm->tx_lock, flags); 2394 gsm_data_kick(gsm); 2395 if (gsm->tx_bytes < TX_THRESH_LO) { 2396 gsm_dlci_data_sweep(gsm); 2397 } 2398 spin_unlock_irqrestore(&gsm->tx_lock, flags); 2399 } 2400 2401 /** 2402 * gsmld_read - read function for tty 2403 * @tty: tty device 2404 * @file: file object 2405 * @buf: userspace buffer pointer 2406 * @nr: size of I/O 2407 * 2408 * Perform reads for the line discipline. We are guaranteed that the 2409 * line discipline will not be closed under us but we may get multiple 2410 * parallel readers and must handle this ourselves. We may also get 2411 * a hangup. Always called in user context, may sleep. 2412 * 2413 * This code must be sure never to sleep through a hangup. 2414 */ 2415 2416 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, 2417 unsigned char __user *buf, size_t nr) 2418 { 2419 return -EOPNOTSUPP; 2420 } 2421 2422 /** 2423 * gsmld_write - write function for tty 2424 * @tty: tty device 2425 * @file: file object 2426 * @buf: userspace buffer pointer 2427 * @nr: size of I/O 2428 * 2429 * Called when the owner of the device wants to send a frame 2430 * itself (or some other control data). The data is transferred 2431 * as-is and must be properly framed and checksummed as appropriate 2432 * by userspace. Frames are either sent whole or not at all as this 2433 * avoids pain user side. 2434 */ 2435 2436 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file, 2437 const unsigned char *buf, size_t nr) 2438 { 2439 int space = tty_write_room(tty); 2440 if (space >= nr) 2441 return tty->ops->write(tty, buf, nr); 2442 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 2443 return -ENOBUFS; 2444 } 2445 2446 /** 2447 * gsmld_poll - poll method for N_GSM0710 2448 * @tty: terminal device 2449 * @file: file accessing it 2450 * @wait: poll table 2451 * 2452 * Called when the line discipline is asked to poll() for data or 2453 * for special events. This code is not serialized with respect to 2454 * other events save open/close. 2455 * 2456 * This code must be sure never to sleep through a hangup. 2457 * Called without the kernel lock held - fine 2458 */ 2459 2460 static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file, 2461 poll_table *wait) 2462 { 2463 unsigned int mask = 0; 2464 struct gsm_mux *gsm = tty->disc_data; 2465 2466 poll_wait(file, &tty->read_wait, wait); 2467 poll_wait(file, &tty->write_wait, wait); 2468 if (tty_hung_up_p(file)) 2469 mask |= POLLHUP; 2470 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0) 2471 mask |= POLLOUT | POLLWRNORM; 2472 if (gsm->dead) 2473 mask |= POLLHUP; 2474 return mask; 2475 } 2476 2477 static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm, 2478 struct gsm_config *c) 2479 { 2480 int need_close = 0; 2481 int need_restart = 0; 2482 2483 /* Stuff we don't support yet - UI or I frame transport, windowing */ 2484 if ((c->adaption != 1 && c->adaption != 2) || c->k) 2485 return -EOPNOTSUPP; 2486 /* Check the MRU/MTU range looks sane */ 2487 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8) 2488 return -EINVAL; 2489 if (c->n2 < 3) 2490 return -EINVAL; 2491 if (c->encapsulation > 1) /* Basic, advanced, no I */ 2492 return -EINVAL; 2493 if (c->initiator > 1) 2494 return -EINVAL; 2495 if (c->i == 0 || c->i > 2) /* UIH and UI only */ 2496 return -EINVAL; 2497 /* 2498 * See what is needed for reconfiguration 2499 */ 2500 2501 /* Timing fields */ 2502 if (c->t1 != 0 && c->t1 != gsm->t1) 2503 need_restart = 1; 2504 if (c->t2 != 0 && c->t2 != gsm->t2) 2505 need_restart = 1; 2506 if (c->encapsulation != gsm->encoding) 2507 need_restart = 1; 2508 if (c->adaption != gsm->adaption) 2509 need_restart = 1; 2510 /* Requires care */ 2511 if (c->initiator != gsm->initiator) 2512 need_close = 1; 2513 if (c->mru != gsm->mru) 2514 need_restart = 1; 2515 if (c->mtu != gsm->mtu) 2516 need_restart = 1; 2517 2518 /* 2519 * Close down what is needed, restart and initiate the new 2520 * configuration 2521 */ 2522 2523 if (need_close || need_restart) { 2524 gsm_dlci_begin_close(gsm->dlci[0]); 2525 /* This will timeout if the link is down due to N2 expiring */ 2526 wait_event_interruptible(gsm->event, 2527 gsm->dlci[0]->state == DLCI_CLOSED); 2528 if (signal_pending(current)) 2529 return -EINTR; 2530 } 2531 if (need_restart) 2532 gsm_cleanup_mux(gsm); 2533 2534 gsm->initiator = c->initiator; 2535 gsm->mru = c->mru; 2536 gsm->mtu = c->mtu; 2537 gsm->encoding = c->encapsulation; 2538 gsm->adaption = c->adaption; 2539 gsm->n2 = c->n2; 2540 2541 if (c->i == 1) 2542 gsm->ftype = UIH; 2543 else if (c->i == 2) 2544 gsm->ftype = UI; 2545 2546 if (c->t1) 2547 gsm->t1 = c->t1; 2548 if (c->t2) 2549 gsm->t2 = c->t2; 2550 2551 /* FIXME: We need to separate activation/deactivation from adding 2552 and removing from the mux array */ 2553 if (need_restart) 2554 gsm_activate_mux(gsm); 2555 if (gsm->initiator && need_close) 2556 gsm_dlci_begin_open(gsm->dlci[0]); 2557 return 0; 2558 } 2559 2560 static int gsmld_ioctl(struct tty_struct *tty, struct file *file, 2561 unsigned int cmd, unsigned long arg) 2562 { 2563 struct gsm_config c; 2564 struct gsm_mux *gsm = tty->disc_data; 2565 2566 switch (cmd) { 2567 case GSMIOC_GETCONF: 2568 memset(&c, 0, sizeof(c)); 2569 c.adaption = gsm->adaption; 2570 c.encapsulation = gsm->encoding; 2571 c.initiator = gsm->initiator; 2572 c.t1 = gsm->t1; 2573 c.t2 = gsm->t2; 2574 c.t3 = 0; /* Not supported */ 2575 c.n2 = gsm->n2; 2576 if (gsm->ftype == UIH) 2577 c.i = 1; 2578 else 2579 c.i = 2; 2580 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i); 2581 c.mru = gsm->mru; 2582 c.mtu = gsm->mtu; 2583 c.k = 0; 2584 if (copy_to_user((void *)arg, &c, sizeof(c))) 2585 return -EFAULT; 2586 return 0; 2587 case GSMIOC_SETCONF: 2588 if (copy_from_user(&c, (void *)arg, sizeof(c))) 2589 return -EFAULT; 2590 return gsmld_config(tty, gsm, &c); 2591 default: 2592 return n_tty_ioctl_helper(tty, file, cmd, arg); 2593 } 2594 } 2595 2596 /* 2597 * Network interface 2598 * 2599 */ 2600 2601 static int gsm_mux_net_open(struct net_device *net) 2602 { 2603 pr_debug("%s called\n", __func__); 2604 netif_start_queue(net); 2605 return 0; 2606 } 2607 2608 static int gsm_mux_net_close(struct net_device *net) 2609 { 2610 netif_stop_queue(net); 2611 return 0; 2612 } 2613 2614 static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net) 2615 { 2616 return &((struct gsm_mux_net *)netdev_priv(net))->stats; 2617 } 2618 static void dlci_net_free(struct gsm_dlci *dlci) 2619 { 2620 if (!dlci->net) { 2621 WARN_ON(1); 2622 return; 2623 } 2624 dlci->adaption = dlci->prev_adaption; 2625 dlci->data = dlci->prev_data; 2626 free_netdev(dlci->net); 2627 dlci->net = NULL; 2628 } 2629 static void net_free(struct kref *ref) 2630 { 2631 struct gsm_mux_net *mux_net; 2632 struct gsm_dlci *dlci; 2633 2634 mux_net = container_of(ref, struct gsm_mux_net, ref); 2635 dlci = mux_net->dlci; 2636 2637 if (dlci->net) { 2638 unregister_netdev(dlci->net); 2639 dlci_net_free(dlci); 2640 } 2641 } 2642 2643 static inline void muxnet_get(struct gsm_mux_net *mux_net) 2644 { 2645 kref_get(&mux_net->ref); 2646 } 2647 2648 static inline void muxnet_put(struct gsm_mux_net *mux_net) 2649 { 2650 kref_put(&mux_net->ref, net_free); 2651 } 2652 2653 static int gsm_mux_net_start_xmit(struct sk_buff *skb, 2654 struct net_device *net) 2655 { 2656 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net); 2657 struct gsm_dlci *dlci = mux_net->dlci; 2658 muxnet_get(mux_net); 2659 2660 skb_queue_head(&dlci->skb_list, skb); 2661 STATS(net).tx_packets++; 2662 STATS(net).tx_bytes += skb->len; 2663 gsm_dlci_data_kick(dlci); 2664 /* And tell the kernel when the last transmit started. */ 2665 net->trans_start = jiffies; 2666 muxnet_put(mux_net); 2667 return NETDEV_TX_OK; 2668 } 2669 2670 /* called when a packet did not ack after watchdogtimeout */ 2671 static void gsm_mux_net_tx_timeout(struct net_device *net) 2672 { 2673 /* Tell syslog we are hosed. */ 2674 dev_dbg(&net->dev, "Tx timed out.\n"); 2675 2676 /* Update statistics */ 2677 STATS(net).tx_errors++; 2678 } 2679 2680 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci, 2681 unsigned char *in_buf, int size) 2682 { 2683 struct net_device *net = dlci->net; 2684 struct sk_buff *skb; 2685 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net); 2686 muxnet_get(mux_net); 2687 2688 /* Allocate an sk_buff */ 2689 skb = dev_alloc_skb(size + NET_IP_ALIGN); 2690 if (!skb) { 2691 /* We got no receive buffer. */ 2692 STATS(net).rx_dropped++; 2693 muxnet_put(mux_net); 2694 return; 2695 } 2696 skb_reserve(skb, NET_IP_ALIGN); 2697 memcpy(skb_put(skb, size), in_buf, size); 2698 2699 skb->dev = net; 2700 skb->protocol = __constant_htons(ETH_P_IP); 2701 2702 /* Ship it off to the kernel */ 2703 netif_rx(skb); 2704 2705 /* update out statistics */ 2706 STATS(net).rx_packets++; 2707 STATS(net).rx_bytes += size; 2708 muxnet_put(mux_net); 2709 return; 2710 } 2711 2712 static int gsm_change_mtu(struct net_device *net, int new_mtu) 2713 { 2714 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net); 2715 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu)) 2716 return -EINVAL; 2717 net->mtu = new_mtu; 2718 return 0; 2719 } 2720 2721 static void gsm_mux_net_init(struct net_device *net) 2722 { 2723 static const struct net_device_ops gsm_netdev_ops = { 2724 .ndo_open = gsm_mux_net_open, 2725 .ndo_stop = gsm_mux_net_close, 2726 .ndo_start_xmit = gsm_mux_net_start_xmit, 2727 .ndo_tx_timeout = gsm_mux_net_tx_timeout, 2728 .ndo_get_stats = gsm_mux_net_get_stats, 2729 .ndo_change_mtu = gsm_change_mtu, 2730 }; 2731 2732 net->netdev_ops = &gsm_netdev_ops; 2733 2734 /* fill in the other fields */ 2735 net->watchdog_timeo = GSM_NET_TX_TIMEOUT; 2736 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 2737 net->type = ARPHRD_NONE; 2738 net->tx_queue_len = 10; 2739 } 2740 2741 2742 /* caller holds the dlci mutex */ 2743 static void gsm_destroy_network(struct gsm_dlci *dlci) 2744 { 2745 struct gsm_mux_net *mux_net; 2746 2747 pr_debug("destroy network interface"); 2748 if (!dlci->net) 2749 return; 2750 mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net); 2751 muxnet_put(mux_net); 2752 } 2753 2754 2755 /* caller holds the dlci mutex */ 2756 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc) 2757 { 2758 char *netname; 2759 int retval = 0; 2760 struct net_device *net; 2761 struct gsm_mux_net *mux_net; 2762 2763 if (!capable(CAP_NET_ADMIN)) 2764 return -EPERM; 2765 2766 /* Already in a non tty mode */ 2767 if (dlci->adaption > 2) 2768 return -EBUSY; 2769 2770 if (nc->protocol != htons(ETH_P_IP)) 2771 return -EPROTONOSUPPORT; 2772 2773 if (nc->adaption != 3 && nc->adaption != 4) 2774 return -EPROTONOSUPPORT; 2775 2776 pr_debug("create network interface"); 2777 2778 netname = "gsm%d"; 2779 if (nc->if_name[0] != '\0') 2780 netname = nc->if_name; 2781 net = alloc_netdev(sizeof(struct gsm_mux_net), 2782 netname, 2783 gsm_mux_net_init); 2784 if (!net) { 2785 pr_err("alloc_netdev failed"); 2786 return -ENOMEM; 2787 } 2788 net->mtu = dlci->gsm->mtu; 2789 mux_net = (struct gsm_mux_net *)netdev_priv(net); 2790 mux_net->dlci = dlci; 2791 kref_init(&mux_net->ref); 2792 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */ 2793 2794 /* reconfigure dlci for network */ 2795 dlci->prev_adaption = dlci->adaption; 2796 dlci->prev_data = dlci->data; 2797 dlci->adaption = nc->adaption; 2798 dlci->data = gsm_mux_rx_netchar; 2799 dlci->net = net; 2800 2801 pr_debug("register netdev"); 2802 retval = register_netdev(net); 2803 if (retval) { 2804 pr_err("network register fail %d\n", retval); 2805 dlci_net_free(dlci); 2806 return retval; 2807 } 2808 return net->ifindex; /* return network index */ 2809 } 2810 2811 /* Line discipline for real tty */ 2812 struct tty_ldisc_ops tty_ldisc_packet = { 2813 .owner = THIS_MODULE, 2814 .magic = TTY_LDISC_MAGIC, 2815 .name = "n_gsm", 2816 .open = gsmld_open, 2817 .close = gsmld_close, 2818 .flush_buffer = gsmld_flush_buffer, 2819 .chars_in_buffer = gsmld_chars_in_buffer, 2820 .read = gsmld_read, 2821 .write = gsmld_write, 2822 .ioctl = gsmld_ioctl, 2823 .poll = gsmld_poll, 2824 .receive_buf = gsmld_receive_buf, 2825 .write_wakeup = gsmld_write_wakeup 2826 }; 2827 2828 /* 2829 * Virtual tty side 2830 */ 2831 2832 #define TX_SIZE 512 2833 2834 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) 2835 { 2836 u8 modembits[5]; 2837 struct gsm_control *ctrl; 2838 int len = 2; 2839 2840 if (brk) 2841 len++; 2842 2843 modembits[0] = len << 1 | EA; /* Data bytes */ 2844 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */ 2845 modembits[2] = gsm_encode_modem(dlci) << 1 | EA; 2846 if (brk) 2847 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */ 2848 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1); 2849 if (ctrl == NULL) 2850 return -ENOMEM; 2851 return gsm_control_wait(dlci->gsm, ctrl); 2852 } 2853 2854 static int gsm_carrier_raised(struct tty_port *port) 2855 { 2856 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2857 /* Not yet open so no carrier info */ 2858 if (dlci->state != DLCI_OPEN) 2859 return 0; 2860 if (debug & 2) 2861 return 1; 2862 return dlci->modem_rx & TIOCM_CD; 2863 } 2864 2865 static void gsm_dtr_rts(struct tty_port *port, int onoff) 2866 { 2867 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2868 unsigned int modem_tx = dlci->modem_tx; 2869 if (onoff) 2870 modem_tx |= TIOCM_DTR | TIOCM_RTS; 2871 else 2872 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); 2873 if (modem_tx != dlci->modem_tx) { 2874 dlci->modem_tx = modem_tx; 2875 gsmtty_modem_update(dlci, 0); 2876 } 2877 } 2878 2879 static const struct tty_port_operations gsm_port_ops = { 2880 .carrier_raised = gsm_carrier_raised, 2881 .dtr_rts = gsm_dtr_rts, 2882 .destruct = gsm_dlci_free, 2883 }; 2884 2885 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty) 2886 { 2887 struct gsm_mux *gsm; 2888 struct gsm_dlci *dlci; 2889 unsigned int line = tty->index; 2890 unsigned int mux = line >> 6; 2891 bool alloc = false; 2892 int ret; 2893 2894 line = line & 0x3F; 2895 2896 if (mux >= MAX_MUX) 2897 return -ENXIO; 2898 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */ 2899 if (gsm_mux[mux] == NULL) 2900 return -EUNATCH; 2901 if (line == 0 || line > 61) /* 62/63 reserved */ 2902 return -ECHRNG; 2903 gsm = gsm_mux[mux]; 2904 if (gsm->dead) 2905 return -EL2HLT; 2906 /* If DLCI 0 is not yet fully open return an error. 2907 This is ok from a locking 2908 perspective as we don't have to worry about this 2909 if DLCI0 is lost */ 2910 mutex_lock(&gsm->mutex); 2911 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) { 2912 mutex_unlock(&gsm->mutex); 2913 return -EL2NSYNC; 2914 } 2915 dlci = gsm->dlci[line]; 2916 if (dlci == NULL) { 2917 alloc = true; 2918 dlci = gsm_dlci_alloc(gsm, line); 2919 } 2920 if (dlci == NULL) { 2921 mutex_unlock(&gsm->mutex); 2922 return -ENOMEM; 2923 } 2924 ret = tty_port_install(&dlci->port, driver, tty); 2925 if (ret) { 2926 if (alloc) 2927 dlci_put(dlci); 2928 mutex_unlock(&gsm->mutex); 2929 return ret; 2930 } 2931 2932 dlci_get(dlci); 2933 dlci_get(gsm->dlci[0]); 2934 mux_get(gsm); 2935 tty->driver_data = dlci; 2936 mutex_unlock(&gsm->mutex); 2937 2938 return 0; 2939 } 2940 2941 static int gsmtty_open(struct tty_struct *tty, struct file *filp) 2942 { 2943 struct gsm_dlci *dlci = tty->driver_data; 2944 struct tty_port *port = &dlci->port; 2945 2946 port->count++; 2947 tty_port_tty_set(port, tty); 2948 2949 dlci->modem_rx = 0; 2950 /* We could in theory open and close before we wait - eg if we get 2951 a DM straight back. This is ok as that will have caused a hangup */ 2952 set_bit(ASYNCB_INITIALIZED, &port->flags); 2953 /* Start sending off SABM messages */ 2954 gsm_dlci_begin_open(dlci); 2955 /* And wait for virtual carrier */ 2956 return tty_port_block_til_ready(port, tty, filp); 2957 } 2958 2959 static void gsmtty_close(struct tty_struct *tty, struct file *filp) 2960 { 2961 struct gsm_dlci *dlci = tty->driver_data; 2962 struct gsm_mux *gsm; 2963 2964 if (dlci == NULL) 2965 return; 2966 if (dlci->state == DLCI_CLOSED) 2967 return; 2968 mutex_lock(&dlci->mutex); 2969 gsm_destroy_network(dlci); 2970 mutex_unlock(&dlci->mutex); 2971 gsm = dlci->gsm; 2972 if (tty_port_close_start(&dlci->port, tty, filp) == 0) 2973 return; 2974 gsm_dlci_begin_close(dlci); 2975 if (test_bit(ASYNCB_INITIALIZED, &dlci->port.flags)) { 2976 if (C_HUPCL(tty)) 2977 tty_port_lower_dtr_rts(&dlci->port); 2978 } 2979 tty_port_close_end(&dlci->port, tty); 2980 tty_port_tty_set(&dlci->port, NULL); 2981 return; 2982 } 2983 2984 static void gsmtty_hangup(struct tty_struct *tty) 2985 { 2986 struct gsm_dlci *dlci = tty->driver_data; 2987 if (dlci->state == DLCI_CLOSED) 2988 return; 2989 tty_port_hangup(&dlci->port); 2990 gsm_dlci_begin_close(dlci); 2991 } 2992 2993 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf, 2994 int len) 2995 { 2996 int sent; 2997 struct gsm_dlci *dlci = tty->driver_data; 2998 if (dlci->state == DLCI_CLOSED) 2999 return -EINVAL; 3000 /* Stuff the bytes into the fifo queue */ 3001 sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock); 3002 /* Need to kick the channel */ 3003 gsm_dlci_data_kick(dlci); 3004 return sent; 3005 } 3006 3007 static int gsmtty_write_room(struct tty_struct *tty) 3008 { 3009 struct gsm_dlci *dlci = tty->driver_data; 3010 if (dlci->state == DLCI_CLOSED) 3011 return -EINVAL; 3012 return TX_SIZE - kfifo_len(dlci->fifo); 3013 } 3014 3015 static int gsmtty_chars_in_buffer(struct tty_struct *tty) 3016 { 3017 struct gsm_dlci *dlci = tty->driver_data; 3018 if (dlci->state == DLCI_CLOSED) 3019 return -EINVAL; 3020 return kfifo_len(dlci->fifo); 3021 } 3022 3023 static void gsmtty_flush_buffer(struct tty_struct *tty) 3024 { 3025 struct gsm_dlci *dlci = tty->driver_data; 3026 if (dlci->state == DLCI_CLOSED) 3027 return; 3028 /* Caution needed: If we implement reliable transport classes 3029 then the data being transmitted can't simply be junked once 3030 it has first hit the stack. Until then we can just blow it 3031 away */ 3032 kfifo_reset(dlci->fifo); 3033 /* Need to unhook this DLCI from the transmit queue logic */ 3034 } 3035 3036 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout) 3037 { 3038 /* The FIFO handles the queue so the kernel will do the right 3039 thing waiting on chars_in_buffer before calling us. No work 3040 to do here */ 3041 } 3042 3043 static int gsmtty_tiocmget(struct tty_struct *tty) 3044 { 3045 struct gsm_dlci *dlci = tty->driver_data; 3046 if (dlci->state == DLCI_CLOSED) 3047 return -EINVAL; 3048 return dlci->modem_rx; 3049 } 3050 3051 static int gsmtty_tiocmset(struct tty_struct *tty, 3052 unsigned int set, unsigned int clear) 3053 { 3054 struct gsm_dlci *dlci = tty->driver_data; 3055 unsigned int modem_tx = dlci->modem_tx; 3056 3057 if (dlci->state == DLCI_CLOSED) 3058 return -EINVAL; 3059 modem_tx &= ~clear; 3060 modem_tx |= set; 3061 3062 if (modem_tx != dlci->modem_tx) { 3063 dlci->modem_tx = modem_tx; 3064 return gsmtty_modem_update(dlci, 0); 3065 } 3066 return 0; 3067 } 3068 3069 3070 static int gsmtty_ioctl(struct tty_struct *tty, 3071 unsigned int cmd, unsigned long arg) 3072 { 3073 struct gsm_dlci *dlci = tty->driver_data; 3074 struct gsm_netconfig nc; 3075 int index; 3076 3077 if (dlci->state == DLCI_CLOSED) 3078 return -EINVAL; 3079 switch (cmd) { 3080 case GSMIOC_ENABLE_NET: 3081 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc))) 3082 return -EFAULT; 3083 nc.if_name[IFNAMSIZ-1] = '\0'; 3084 /* return net interface index or error code */ 3085 mutex_lock(&dlci->mutex); 3086 index = gsm_create_network(dlci, &nc); 3087 mutex_unlock(&dlci->mutex); 3088 if (copy_to_user((void __user *)arg, &nc, sizeof(nc))) 3089 return -EFAULT; 3090 return index; 3091 case GSMIOC_DISABLE_NET: 3092 if (!capable(CAP_NET_ADMIN)) 3093 return -EPERM; 3094 mutex_lock(&dlci->mutex); 3095 gsm_destroy_network(dlci); 3096 mutex_unlock(&dlci->mutex); 3097 return 0; 3098 default: 3099 return -ENOIOCTLCMD; 3100 } 3101 } 3102 3103 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old) 3104 { 3105 struct gsm_dlci *dlci = tty->driver_data; 3106 if (dlci->state == DLCI_CLOSED) 3107 return; 3108 /* For the moment its fixed. In actual fact the speed information 3109 for the virtual channel can be propogated in both directions by 3110 the RPN control message. This however rapidly gets nasty as we 3111 then have to remap modem signals each way according to whether 3112 our virtual cable is null modem etc .. */ 3113 tty_termios_copy_hw(&tty->termios, old); 3114 } 3115 3116 static void gsmtty_throttle(struct tty_struct *tty) 3117 { 3118 struct gsm_dlci *dlci = tty->driver_data; 3119 if (dlci->state == DLCI_CLOSED) 3120 return; 3121 if (tty->termios.c_cflag & CRTSCTS) 3122 dlci->modem_tx &= ~TIOCM_DTR; 3123 dlci->throttled = 1; 3124 /* Send an MSC with DTR cleared */ 3125 gsmtty_modem_update(dlci, 0); 3126 } 3127 3128 static void gsmtty_unthrottle(struct tty_struct *tty) 3129 { 3130 struct gsm_dlci *dlci = tty->driver_data; 3131 if (dlci->state == DLCI_CLOSED) 3132 return; 3133 if (tty->termios.c_cflag & CRTSCTS) 3134 dlci->modem_tx |= TIOCM_DTR; 3135 dlci->throttled = 0; 3136 /* Send an MSC with DTR set */ 3137 gsmtty_modem_update(dlci, 0); 3138 } 3139 3140 static int gsmtty_break_ctl(struct tty_struct *tty, int state) 3141 { 3142 struct gsm_dlci *dlci = tty->driver_data; 3143 int encode = 0; /* Off */ 3144 if (dlci->state == DLCI_CLOSED) 3145 return -EINVAL; 3146 3147 if (state == -1) /* "On indefinitely" - we can't encode this 3148 properly */ 3149 encode = 0x0F; 3150 else if (state > 0) { 3151 encode = state / 200; /* mS to encoding */ 3152 if (encode > 0x0F) 3153 encode = 0x0F; /* Best effort */ 3154 } 3155 return gsmtty_modem_update(dlci, encode); 3156 } 3157 3158 static void gsmtty_remove(struct tty_driver *driver, struct tty_struct *tty) 3159 { 3160 struct gsm_dlci *dlci = tty->driver_data; 3161 struct gsm_mux *gsm = dlci->gsm; 3162 3163 dlci_put(dlci); 3164 dlci_put(gsm->dlci[0]); 3165 mux_put(gsm); 3166 driver->ttys[tty->index] = NULL; 3167 } 3168 3169 /* Virtual ttys for the demux */ 3170 static const struct tty_operations gsmtty_ops = { 3171 .install = gsmtty_install, 3172 .open = gsmtty_open, 3173 .close = gsmtty_close, 3174 .write = gsmtty_write, 3175 .write_room = gsmtty_write_room, 3176 .chars_in_buffer = gsmtty_chars_in_buffer, 3177 .flush_buffer = gsmtty_flush_buffer, 3178 .ioctl = gsmtty_ioctl, 3179 .throttle = gsmtty_throttle, 3180 .unthrottle = gsmtty_unthrottle, 3181 .set_termios = gsmtty_set_termios, 3182 .hangup = gsmtty_hangup, 3183 .wait_until_sent = gsmtty_wait_until_sent, 3184 .tiocmget = gsmtty_tiocmget, 3185 .tiocmset = gsmtty_tiocmset, 3186 .break_ctl = gsmtty_break_ctl, 3187 .remove = gsmtty_remove, 3188 }; 3189 3190 3191 3192 static int __init gsm_init(void) 3193 { 3194 /* Fill in our line protocol discipline, and register it */ 3195 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet); 3196 if (status != 0) { 3197 pr_err("n_gsm: can't register line discipline (err = %d)\n", 3198 status); 3199 return status; 3200 } 3201 3202 gsm_tty_driver = alloc_tty_driver(256); 3203 if (!gsm_tty_driver) { 3204 tty_unregister_ldisc(N_GSM0710); 3205 pr_err("gsm_init: tty allocation failed.\n"); 3206 return -EINVAL; 3207 } 3208 gsm_tty_driver->driver_name = "gsmtty"; 3209 gsm_tty_driver->name = "gsmtty"; 3210 gsm_tty_driver->major = 0; /* Dynamic */ 3211 gsm_tty_driver->minor_start = 0; 3212 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; 3213 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL; 3214 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV 3215 | TTY_DRIVER_HARDWARE_BREAK; 3216 gsm_tty_driver->init_termios = tty_std_termios; 3217 /* Fixme */ 3218 gsm_tty_driver->init_termios.c_lflag &= ~ECHO; 3219 tty_set_operations(gsm_tty_driver, &gsmtty_ops); 3220 3221 spin_lock_init(&gsm_mux_lock); 3222 3223 if (tty_register_driver(gsm_tty_driver)) { 3224 put_tty_driver(gsm_tty_driver); 3225 tty_unregister_ldisc(N_GSM0710); 3226 pr_err("gsm_init: tty registration failed.\n"); 3227 return -EBUSY; 3228 } 3229 pr_debug("gsm_init: loaded as %d,%d.\n", 3230 gsm_tty_driver->major, gsm_tty_driver->minor_start); 3231 return 0; 3232 } 3233 3234 static void __exit gsm_exit(void) 3235 { 3236 int status = tty_unregister_ldisc(N_GSM0710); 3237 if (status != 0) 3238 pr_err("n_gsm: can't unregister line discipline (err = %d)\n", 3239 status); 3240 tty_unregister_driver(gsm_tty_driver); 3241 put_tty_driver(gsm_tty_driver); 3242 } 3243 3244 module_init(gsm_init); 3245 module_exit(gsm_exit); 3246 3247 3248 MODULE_LICENSE("GPL"); 3249 MODULE_ALIAS_LDISC(N_GSM0710); 3250