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 if (brk & 0x01) 1071 tty_insert_flip_char(tty, 0, TTY_BREAK); 1072 } 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_struct *tty; 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 /* See if we have an uplink tty */ 1164 tty = tty_port_tty_get(&gsm->dlci[addr]->port); 1165 1166 if (tty) { 1167 if (bits & 2) 1168 tty_insert_flip_char(tty, 0, TTY_OVERRUN); 1169 if (bits & 4) 1170 tty_insert_flip_char(tty, 0, TTY_PARITY); 1171 if (bits & 8) 1172 tty_insert_flip_char(tty, 0, TTY_FRAME); 1173 tty_flip_buffer_push(tty); 1174 tty_kref_put(tty); 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 struct tty_struct *tty = tty_port_tty_get(&dlci->port); 1423 if (tty) { 1424 tty_hangup(tty); 1425 tty_kref_put(tty); 1426 } 1427 kfifo_reset(dlci->fifo); 1428 } else 1429 dlci->gsm->dead = 1; 1430 wake_up(&dlci->gsm->event); 1431 /* A DLCI 0 close is a MUX termination so we need to kick that 1432 back to userspace somehow */ 1433 } 1434 1435 /** 1436 * gsm_dlci_open - a DLCI has opened 1437 * @dlci: DLCI that opened 1438 * 1439 * Perform processing when moving a DLCI into open state. 1440 */ 1441 1442 static void gsm_dlci_open(struct gsm_dlci *dlci) 1443 { 1444 /* Note that SABM UA .. SABM UA first UA lost can mean that we go 1445 open -> open */ 1446 del_timer(&dlci->t1); 1447 /* This will let a tty open continue */ 1448 dlci->state = DLCI_OPEN; 1449 if (debug & 8) 1450 pr_debug("DLCI %d goes open.\n", dlci->addr); 1451 wake_up(&dlci->gsm->event); 1452 } 1453 1454 /** 1455 * gsm_dlci_t1 - T1 timer expiry 1456 * @dlci: DLCI that opened 1457 * 1458 * The T1 timer handles retransmits of control frames (essentially of 1459 * SABM and DISC). We resend the command until the retry count runs out 1460 * in which case an opening port goes back to closed and a closing port 1461 * is simply put into closed state (any further frames from the other 1462 * end will get a DM response) 1463 */ 1464 1465 static void gsm_dlci_t1(unsigned long data) 1466 { 1467 struct gsm_dlci *dlci = (struct gsm_dlci *)data; 1468 struct gsm_mux *gsm = dlci->gsm; 1469 1470 switch (dlci->state) { 1471 case DLCI_OPENING: 1472 dlci->retries--; 1473 if (dlci->retries) { 1474 gsm_command(dlci->gsm, dlci->addr, SABM|PF); 1475 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1476 } else 1477 gsm_dlci_close(dlci); 1478 break; 1479 case DLCI_CLOSING: 1480 dlci->retries--; 1481 if (dlci->retries) { 1482 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 1483 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1484 } else 1485 gsm_dlci_close(dlci); 1486 break; 1487 } 1488 } 1489 1490 /** 1491 * gsm_dlci_begin_open - start channel open procedure 1492 * @dlci: DLCI to open 1493 * 1494 * Commence opening a DLCI from the Linux side. We issue SABM messages 1495 * to the modem which should then reply with a UA, at which point we 1496 * will move into open state. Opening is done asynchronously with retry 1497 * running off timers and the responses. 1498 */ 1499 1500 static void gsm_dlci_begin_open(struct gsm_dlci *dlci) 1501 { 1502 struct gsm_mux *gsm = dlci->gsm; 1503 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING) 1504 return; 1505 dlci->retries = gsm->n2; 1506 dlci->state = DLCI_OPENING; 1507 gsm_command(dlci->gsm, dlci->addr, SABM|PF); 1508 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1509 } 1510 1511 /** 1512 * gsm_dlci_begin_close - start channel open procedure 1513 * @dlci: DLCI to open 1514 * 1515 * Commence closing a DLCI from the Linux side. We issue DISC messages 1516 * to the modem which should then reply with a UA, at which point we 1517 * will move into closed state. Closing is done asynchronously with retry 1518 * off timers. We may also receive a DM reply from the other end which 1519 * indicates the channel was already closed. 1520 */ 1521 1522 static void gsm_dlci_begin_close(struct gsm_dlci *dlci) 1523 { 1524 struct gsm_mux *gsm = dlci->gsm; 1525 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING) 1526 return; 1527 dlci->retries = gsm->n2; 1528 dlci->state = DLCI_CLOSING; 1529 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 1530 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1531 } 1532 1533 /** 1534 * gsm_dlci_data - data arrived 1535 * @dlci: channel 1536 * @data: block of bytes received 1537 * @len: length of received block 1538 * 1539 * A UI or UIH frame has arrived which contains data for a channel 1540 * other than the control channel. If the relevant virtual tty is 1541 * open we shovel the bits down it, if not we drop them. 1542 */ 1543 1544 static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen) 1545 { 1546 /* krefs .. */ 1547 struct tty_port *port = &dlci->port; 1548 struct tty_struct *tty = tty_port_tty_get(port); 1549 unsigned int modem = 0; 1550 int len = clen; 1551 1552 if (debug & 16) 1553 pr_debug("%d bytes for tty %p\n", len, tty); 1554 if (tty) { 1555 switch (dlci->adaption) { 1556 /* Unsupported types */ 1557 /* Packetised interruptible data */ 1558 case 4: 1559 break; 1560 /* Packetised uininterruptible voice/data */ 1561 case 3: 1562 break; 1563 /* Asynchronous serial with line state in each frame */ 1564 case 2: 1565 while (gsm_read_ea(&modem, *data++) == 0) { 1566 len--; 1567 if (len == 0) 1568 return; 1569 } 1570 gsm_process_modem(tty, dlci, modem, clen); 1571 /* Line state will go via DLCI 0 controls only */ 1572 case 1: 1573 default: 1574 tty_insert_flip_string(tty, data, len); 1575 tty_flip_buffer_push(tty); 1576 } 1577 tty_kref_put(tty); 1578 } 1579 } 1580 1581 /** 1582 * gsm_dlci_control - data arrived on control channel 1583 * @dlci: channel 1584 * @data: block of bytes received 1585 * @len: length of received block 1586 * 1587 * A UI or UIH frame has arrived which contains data for DLCI 0 the 1588 * control channel. This should contain a command EA followed by 1589 * control data bytes. The command EA contains a command/response bit 1590 * and we divide up the work accordingly. 1591 */ 1592 1593 static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len) 1594 { 1595 /* See what command is involved */ 1596 unsigned int command = 0; 1597 while (len-- > 0) { 1598 if (gsm_read_ea(&command, *data++) == 1) { 1599 int clen = *data++; 1600 len--; 1601 /* FIXME: this is properly an EA */ 1602 clen >>= 1; 1603 /* Malformed command ? */ 1604 if (clen > len) 1605 return; 1606 if (command & 1) 1607 gsm_control_message(dlci->gsm, command, 1608 data, clen); 1609 else 1610 gsm_control_response(dlci->gsm, command, 1611 data, clen); 1612 return; 1613 } 1614 } 1615 } 1616 1617 /* 1618 * Allocate/Free DLCI channels 1619 */ 1620 1621 /** 1622 * gsm_dlci_alloc - allocate a DLCI 1623 * @gsm: GSM mux 1624 * @addr: address of the DLCI 1625 * 1626 * Allocate and install a new DLCI object into the GSM mux. 1627 * 1628 * FIXME: review locking races 1629 */ 1630 1631 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr) 1632 { 1633 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC); 1634 if (dlci == NULL) 1635 return NULL; 1636 spin_lock_init(&dlci->lock); 1637 mutex_init(&dlci->mutex); 1638 dlci->fifo = &dlci->_fifo; 1639 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) { 1640 kfree(dlci); 1641 return NULL; 1642 } 1643 1644 skb_queue_head_init(&dlci->skb_list); 1645 init_timer(&dlci->t1); 1646 dlci->t1.function = gsm_dlci_t1; 1647 dlci->t1.data = (unsigned long)dlci; 1648 tty_port_init(&dlci->port); 1649 dlci->port.ops = &gsm_port_ops; 1650 dlci->gsm = gsm; 1651 dlci->addr = addr; 1652 dlci->adaption = gsm->adaption; 1653 dlci->state = DLCI_CLOSED; 1654 if (addr) 1655 dlci->data = gsm_dlci_data; 1656 else 1657 dlci->data = gsm_dlci_command; 1658 gsm->dlci[addr] = dlci; 1659 return dlci; 1660 } 1661 1662 /** 1663 * gsm_dlci_free - free DLCI 1664 * @dlci: DLCI to free 1665 * 1666 * Free up a DLCI. 1667 * 1668 * Can sleep. 1669 */ 1670 static void gsm_dlci_free(struct tty_port *port) 1671 { 1672 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 1673 1674 del_timer_sync(&dlci->t1); 1675 dlci->gsm->dlci[dlci->addr] = NULL; 1676 kfifo_free(dlci->fifo); 1677 while ((dlci->skb = skb_dequeue(&dlci->skb_list))) 1678 dev_kfree_skb(dlci->skb); 1679 kfree(dlci); 1680 } 1681 1682 static inline void dlci_get(struct gsm_dlci *dlci) 1683 { 1684 tty_port_get(&dlci->port); 1685 } 1686 1687 static inline void dlci_put(struct gsm_dlci *dlci) 1688 { 1689 tty_port_put(&dlci->port); 1690 } 1691 1692 /** 1693 * gsm_dlci_release - release DLCI 1694 * @dlci: DLCI to destroy 1695 * 1696 * Release a DLCI. Actual free is deferred until either 1697 * mux is closed or tty is closed - whichever is last. 1698 * 1699 * Can sleep. 1700 */ 1701 static void gsm_dlci_release(struct gsm_dlci *dlci) 1702 { 1703 struct tty_struct *tty = tty_port_tty_get(&dlci->port); 1704 if (tty) { 1705 tty_vhangup(tty); 1706 tty_kref_put(tty); 1707 } 1708 dlci_put(dlci); 1709 } 1710 1711 /* 1712 * LAPBish link layer logic 1713 */ 1714 1715 /** 1716 * gsm_queue - a GSM frame is ready to process 1717 * @gsm: pointer to our gsm mux 1718 * 1719 * At this point in time a frame has arrived and been demangled from 1720 * the line encoding. All the differences between the encodings have 1721 * been handled below us and the frame is unpacked into the structures. 1722 * The fcs holds the header FCS but any data FCS must be added here. 1723 */ 1724 1725 static void gsm_queue(struct gsm_mux *gsm) 1726 { 1727 struct gsm_dlci *dlci; 1728 u8 cr; 1729 int address; 1730 /* We have to sneak a look at the packet body to do the FCS. 1731 A somewhat layering violation in the spec */ 1732 1733 if ((gsm->control & ~PF) == UI) 1734 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len); 1735 if (gsm->encoding == 0){ 1736 /* WARNING: gsm->received_fcs is used for gsm->encoding = 0 only. 1737 In this case it contain the last piece of data 1738 required to generate final CRC */ 1739 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs); 1740 } 1741 if (gsm->fcs != GOOD_FCS) { 1742 gsm->bad_fcs++; 1743 if (debug & 4) 1744 pr_debug("BAD FCS %02x\n", gsm->fcs); 1745 return; 1746 } 1747 address = gsm->address >> 1; 1748 if (address >= NUM_DLCI) 1749 goto invalid; 1750 1751 cr = gsm->address & 1; /* C/R bit */ 1752 1753 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len); 1754 1755 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */ 1756 dlci = gsm->dlci[address]; 1757 1758 switch (gsm->control) { 1759 case SABM|PF: 1760 if (cr == 0) 1761 goto invalid; 1762 if (dlci == NULL) 1763 dlci = gsm_dlci_alloc(gsm, address); 1764 if (dlci == NULL) 1765 return; 1766 if (dlci->dead) 1767 gsm_response(gsm, address, DM); 1768 else { 1769 gsm_response(gsm, address, UA); 1770 gsm_dlci_open(dlci); 1771 } 1772 break; 1773 case DISC|PF: 1774 if (cr == 0) 1775 goto invalid; 1776 if (dlci == NULL || dlci->state == DLCI_CLOSED) { 1777 gsm_response(gsm, address, DM); 1778 return; 1779 } 1780 /* Real close complete */ 1781 gsm_response(gsm, address, UA); 1782 gsm_dlci_close(dlci); 1783 break; 1784 case UA: 1785 case UA|PF: 1786 if (cr == 0 || dlci == NULL) 1787 break; 1788 switch (dlci->state) { 1789 case DLCI_CLOSING: 1790 gsm_dlci_close(dlci); 1791 break; 1792 case DLCI_OPENING: 1793 gsm_dlci_open(dlci); 1794 break; 1795 } 1796 break; 1797 case DM: /* DM can be valid unsolicited */ 1798 case DM|PF: 1799 if (cr) 1800 goto invalid; 1801 if (dlci == NULL) 1802 return; 1803 gsm_dlci_close(dlci); 1804 break; 1805 case UI: 1806 case UI|PF: 1807 case UIH: 1808 case UIH|PF: 1809 #if 0 1810 if (cr) 1811 goto invalid; 1812 #endif 1813 if (dlci == NULL || dlci->state != DLCI_OPEN) { 1814 gsm_command(gsm, address, DM|PF); 1815 return; 1816 } 1817 dlci->data(dlci, gsm->buf, gsm->len); 1818 break; 1819 default: 1820 goto invalid; 1821 } 1822 return; 1823 invalid: 1824 gsm->malformed++; 1825 return; 1826 } 1827 1828 1829 /** 1830 * gsm0_receive - perform processing for non-transparency 1831 * @gsm: gsm data for this ldisc instance 1832 * @c: character 1833 * 1834 * Receive bytes in gsm mode 0 1835 */ 1836 1837 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) 1838 { 1839 unsigned int len; 1840 1841 switch (gsm->state) { 1842 case GSM_SEARCH: /* SOF marker */ 1843 if (c == GSM0_SOF) { 1844 gsm->state = GSM_ADDRESS; 1845 gsm->address = 0; 1846 gsm->len = 0; 1847 gsm->fcs = INIT_FCS; 1848 } 1849 break; 1850 case GSM_ADDRESS: /* Address EA */ 1851 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1852 if (gsm_read_ea(&gsm->address, c)) 1853 gsm->state = GSM_CONTROL; 1854 break; 1855 case GSM_CONTROL: /* Control Byte */ 1856 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1857 gsm->control = c; 1858 gsm->state = GSM_LEN0; 1859 break; 1860 case GSM_LEN0: /* Length EA */ 1861 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1862 if (gsm_read_ea(&gsm->len, c)) { 1863 if (gsm->len > gsm->mru) { 1864 gsm->bad_size++; 1865 gsm->state = GSM_SEARCH; 1866 break; 1867 } 1868 gsm->count = 0; 1869 if (!gsm->len) 1870 gsm->state = GSM_FCS; 1871 else 1872 gsm->state = GSM_DATA; 1873 break; 1874 } 1875 gsm->state = GSM_LEN1; 1876 break; 1877 case GSM_LEN1: 1878 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1879 len = c; 1880 gsm->len |= len << 7; 1881 if (gsm->len > gsm->mru) { 1882 gsm->bad_size++; 1883 gsm->state = GSM_SEARCH; 1884 break; 1885 } 1886 gsm->count = 0; 1887 if (!gsm->len) 1888 gsm->state = GSM_FCS; 1889 else 1890 gsm->state = GSM_DATA; 1891 break; 1892 case GSM_DATA: /* Data */ 1893 gsm->buf[gsm->count++] = c; 1894 if (gsm->count == gsm->len) 1895 gsm->state = GSM_FCS; 1896 break; 1897 case GSM_FCS: /* FCS follows the packet */ 1898 gsm->received_fcs = c; 1899 gsm_queue(gsm); 1900 gsm->state = GSM_SSOF; 1901 break; 1902 case GSM_SSOF: 1903 if (c == GSM0_SOF) { 1904 gsm->state = GSM_SEARCH; 1905 break; 1906 } 1907 break; 1908 } 1909 } 1910 1911 /** 1912 * gsm1_receive - perform processing for non-transparency 1913 * @gsm: gsm data for this ldisc instance 1914 * @c: character 1915 * 1916 * Receive bytes in mode 1 (Advanced option) 1917 */ 1918 1919 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c) 1920 { 1921 if (c == GSM1_SOF) { 1922 /* EOF is only valid in frame if we have got to the data state 1923 and received at least one byte (the FCS) */ 1924 if (gsm->state == GSM_DATA && gsm->count) { 1925 /* Extract the FCS */ 1926 gsm->count--; 1927 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]); 1928 gsm->len = gsm->count; 1929 gsm_queue(gsm); 1930 gsm->state = GSM_START; 1931 return; 1932 } 1933 /* Any partial frame was a runt so go back to start */ 1934 if (gsm->state != GSM_START) { 1935 gsm->malformed++; 1936 gsm->state = GSM_START; 1937 } 1938 /* A SOF in GSM_START means we are still reading idling or 1939 framing bytes */ 1940 return; 1941 } 1942 1943 if (c == GSM1_ESCAPE) { 1944 gsm->escape = 1; 1945 return; 1946 } 1947 1948 /* Only an unescaped SOF gets us out of GSM search */ 1949 if (gsm->state == GSM_SEARCH) 1950 return; 1951 1952 if (gsm->escape) { 1953 c ^= GSM1_ESCAPE_BITS; 1954 gsm->escape = 0; 1955 } 1956 switch (gsm->state) { 1957 case GSM_START: /* First byte after SOF */ 1958 gsm->address = 0; 1959 gsm->state = GSM_ADDRESS; 1960 gsm->fcs = INIT_FCS; 1961 /* Drop through */ 1962 case GSM_ADDRESS: /* Address continuation */ 1963 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1964 if (gsm_read_ea(&gsm->address, c)) 1965 gsm->state = GSM_CONTROL; 1966 break; 1967 case GSM_CONTROL: /* Control Byte */ 1968 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1969 gsm->control = c; 1970 gsm->count = 0; 1971 gsm->state = GSM_DATA; 1972 break; 1973 case GSM_DATA: /* Data */ 1974 if (gsm->count > gsm->mru) { /* Allow one for the FCS */ 1975 gsm->state = GSM_OVERRUN; 1976 gsm->bad_size++; 1977 } else 1978 gsm->buf[gsm->count++] = c; 1979 break; 1980 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */ 1981 break; 1982 } 1983 } 1984 1985 /** 1986 * gsm_error - handle tty error 1987 * @gsm: ldisc data 1988 * @data: byte received (may be invalid) 1989 * @flag: error received 1990 * 1991 * Handle an error in the receipt of data for a frame. Currently we just 1992 * go back to hunting for a SOF. 1993 * 1994 * FIXME: better diagnostics ? 1995 */ 1996 1997 static void gsm_error(struct gsm_mux *gsm, 1998 unsigned char data, unsigned char flag) 1999 { 2000 gsm->state = GSM_SEARCH; 2001 gsm->io_error++; 2002 } 2003 2004 /** 2005 * gsm_cleanup_mux - generic GSM protocol cleanup 2006 * @gsm: our mux 2007 * 2008 * Clean up the bits of the mux which are the same for all framing 2009 * protocols. Remove the mux from the mux table, stop all the timers 2010 * and then shut down each device hanging up the channels as we go. 2011 */ 2012 2013 void gsm_cleanup_mux(struct gsm_mux *gsm) 2014 { 2015 int i; 2016 struct gsm_dlci *dlci = gsm->dlci[0]; 2017 struct gsm_msg *txq, *ntxq; 2018 struct gsm_control *gc; 2019 2020 gsm->dead = 1; 2021 2022 spin_lock(&gsm_mux_lock); 2023 for (i = 0; i < MAX_MUX; i++) { 2024 if (gsm_mux[i] == gsm) { 2025 gsm_mux[i] = NULL; 2026 break; 2027 } 2028 } 2029 spin_unlock(&gsm_mux_lock); 2030 WARN_ON(i == MAX_MUX); 2031 2032 /* In theory disconnecting DLCI 0 is sufficient but for some 2033 modems this is apparently not the case. */ 2034 if (dlci) { 2035 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0); 2036 if (gc) 2037 gsm_control_wait(gsm, gc); 2038 } 2039 del_timer_sync(&gsm->t2_timer); 2040 /* Now we are sure T2 has stopped */ 2041 if (dlci) { 2042 dlci->dead = 1; 2043 gsm_dlci_begin_close(dlci); 2044 wait_event_interruptible(gsm->event, 2045 dlci->state == DLCI_CLOSED); 2046 } 2047 /* Free up any link layer users */ 2048 for (i = 0; i < NUM_DLCI; i++) 2049 if (gsm->dlci[i]) 2050 gsm_dlci_release(gsm->dlci[i]); 2051 /* Now wipe the queues */ 2052 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list) 2053 kfree(txq); 2054 INIT_LIST_HEAD(&gsm->tx_list); 2055 } 2056 EXPORT_SYMBOL_GPL(gsm_cleanup_mux); 2057 2058 /** 2059 * gsm_activate_mux - generic GSM setup 2060 * @gsm: our mux 2061 * 2062 * Set up the bits of the mux which are the same for all framing 2063 * protocols. Add the mux to the mux table so it can be opened and 2064 * finally kick off connecting to DLCI 0 on the modem. 2065 */ 2066 2067 int gsm_activate_mux(struct gsm_mux *gsm) 2068 { 2069 struct gsm_dlci *dlci; 2070 int i = 0; 2071 2072 init_timer(&gsm->t2_timer); 2073 gsm->t2_timer.function = gsm_control_retransmit; 2074 gsm->t2_timer.data = (unsigned long)gsm; 2075 init_waitqueue_head(&gsm->event); 2076 spin_lock_init(&gsm->control_lock); 2077 spin_lock_init(&gsm->tx_lock); 2078 2079 if (gsm->encoding == 0) 2080 gsm->receive = gsm0_receive; 2081 else 2082 gsm->receive = gsm1_receive; 2083 gsm->error = gsm_error; 2084 2085 spin_lock(&gsm_mux_lock); 2086 for (i = 0; i < MAX_MUX; i++) { 2087 if (gsm_mux[i] == NULL) { 2088 gsm->num = i; 2089 gsm_mux[i] = gsm; 2090 break; 2091 } 2092 } 2093 spin_unlock(&gsm_mux_lock); 2094 if (i == MAX_MUX) 2095 return -EBUSY; 2096 2097 dlci = gsm_dlci_alloc(gsm, 0); 2098 if (dlci == NULL) 2099 return -ENOMEM; 2100 gsm->dead = 0; /* Tty opens are now permissible */ 2101 return 0; 2102 } 2103 EXPORT_SYMBOL_GPL(gsm_activate_mux); 2104 2105 /** 2106 * gsm_free_mux - free up a mux 2107 * @mux: mux to free 2108 * 2109 * Dispose of allocated resources for a dead mux 2110 */ 2111 void gsm_free_mux(struct gsm_mux *gsm) 2112 { 2113 kfree(gsm->txframe); 2114 kfree(gsm->buf); 2115 kfree(gsm); 2116 } 2117 EXPORT_SYMBOL_GPL(gsm_free_mux); 2118 2119 /** 2120 * gsm_free_muxr - free up a mux 2121 * @mux: mux to free 2122 * 2123 * Dispose of allocated resources for a dead mux 2124 */ 2125 static void gsm_free_muxr(struct kref *ref) 2126 { 2127 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref); 2128 gsm_free_mux(gsm); 2129 } 2130 2131 static inline void mux_get(struct gsm_mux *gsm) 2132 { 2133 kref_get(&gsm->ref); 2134 } 2135 2136 static inline void mux_put(struct gsm_mux *gsm) 2137 { 2138 kref_put(&gsm->ref, gsm_free_muxr); 2139 } 2140 2141 /** 2142 * gsm_alloc_mux - allocate a mux 2143 * 2144 * Creates a new mux ready for activation. 2145 */ 2146 2147 struct gsm_mux *gsm_alloc_mux(void) 2148 { 2149 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL); 2150 if (gsm == NULL) 2151 return NULL; 2152 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL); 2153 if (gsm->buf == NULL) { 2154 kfree(gsm); 2155 return NULL; 2156 } 2157 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL); 2158 if (gsm->txframe == NULL) { 2159 kfree(gsm->buf); 2160 kfree(gsm); 2161 return NULL; 2162 } 2163 spin_lock_init(&gsm->lock); 2164 kref_init(&gsm->ref); 2165 INIT_LIST_HEAD(&gsm->tx_list); 2166 2167 gsm->t1 = T1; 2168 gsm->t2 = T2; 2169 gsm->n2 = N2; 2170 gsm->ftype = UIH; 2171 gsm->adaption = 1; 2172 gsm->encoding = 1; 2173 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */ 2174 gsm->mtu = 64; 2175 gsm->dead = 1; /* Avoid early tty opens */ 2176 2177 return gsm; 2178 } 2179 EXPORT_SYMBOL_GPL(gsm_alloc_mux); 2180 2181 /** 2182 * gsmld_output - write to link 2183 * @gsm: our mux 2184 * @data: bytes to output 2185 * @len: size 2186 * 2187 * Write a block of data from the GSM mux to the data channel. This 2188 * will eventually be serialized from above but at the moment isn't. 2189 */ 2190 2191 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len) 2192 { 2193 if (tty_write_room(gsm->tty) < len) { 2194 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags); 2195 return -ENOSPC; 2196 } 2197 if (debug & 4) 2198 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET, 2199 data, len); 2200 gsm->tty->ops->write(gsm->tty, data, len); 2201 return len; 2202 } 2203 2204 /** 2205 * gsmld_attach_gsm - mode set up 2206 * @tty: our tty structure 2207 * @gsm: our mux 2208 * 2209 * Set up the MUX for basic mode and commence connecting to the 2210 * modem. Currently called from the line discipline set up but 2211 * will need moving to an ioctl path. 2212 */ 2213 2214 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 2215 { 2216 int ret, i; 2217 int base = gsm->num << 6; /* Base for this MUX */ 2218 2219 gsm->tty = tty_kref_get(tty); 2220 gsm->output = gsmld_output; 2221 ret = gsm_activate_mux(gsm); 2222 if (ret != 0) 2223 tty_kref_put(gsm->tty); 2224 else { 2225 /* Don't register device 0 - this is the control channel and not 2226 a usable tty interface */ 2227 for (i = 1; i < NUM_DLCI; i++) 2228 tty_register_device(gsm_tty_driver, base + i, NULL); 2229 } 2230 return ret; 2231 } 2232 2233 2234 /** 2235 * gsmld_detach_gsm - stop doing 0710 mux 2236 * @tty: tty attached to the mux 2237 * @gsm: mux 2238 * 2239 * Shutdown and then clean up the resources used by the line discipline 2240 */ 2241 2242 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 2243 { 2244 int i; 2245 int base = gsm->num << 6; /* Base for this MUX */ 2246 2247 WARN_ON(tty != gsm->tty); 2248 for (i = 1; i < NUM_DLCI; i++) 2249 tty_unregister_device(gsm_tty_driver, base + i); 2250 gsm_cleanup_mux(gsm); 2251 tty_kref_put(gsm->tty); 2252 gsm->tty = NULL; 2253 } 2254 2255 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, 2256 char *fp, int count) 2257 { 2258 struct gsm_mux *gsm = tty->disc_data; 2259 const unsigned char *dp; 2260 char *f; 2261 int i; 2262 char buf[64]; 2263 char flags; 2264 2265 if (debug & 4) 2266 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET, 2267 cp, count); 2268 2269 for (i = count, dp = cp, f = fp; i; i--, dp++) { 2270 flags = *f++; 2271 switch (flags) { 2272 case TTY_NORMAL: 2273 gsm->receive(gsm, *dp); 2274 break; 2275 case TTY_OVERRUN: 2276 case TTY_BREAK: 2277 case TTY_PARITY: 2278 case TTY_FRAME: 2279 gsm->error(gsm, *dp, flags); 2280 break; 2281 default: 2282 WARN_ONCE(1, "%s: unknown flag %d\n", 2283 tty_name(tty, buf), flags); 2284 break; 2285 } 2286 } 2287 /* FASYNC if needed ? */ 2288 /* If clogged call tty_throttle(tty); */ 2289 } 2290 2291 /** 2292 * gsmld_chars_in_buffer - report available bytes 2293 * @tty: tty device 2294 * 2295 * Report the number of characters buffered to be delivered to user 2296 * at this instant in time. 2297 * 2298 * Locking: gsm lock 2299 */ 2300 2301 static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty) 2302 { 2303 return 0; 2304 } 2305 2306 /** 2307 * gsmld_flush_buffer - clean input queue 2308 * @tty: terminal device 2309 * 2310 * Flush the input buffer. Called when the line discipline is 2311 * being closed, when the tty layer wants the buffer flushed (eg 2312 * at hangup). 2313 */ 2314 2315 static void gsmld_flush_buffer(struct tty_struct *tty) 2316 { 2317 } 2318 2319 /** 2320 * gsmld_close - close the ldisc for this tty 2321 * @tty: device 2322 * 2323 * Called from the terminal layer when this line discipline is 2324 * being shut down, either because of a close or becsuse of a 2325 * discipline change. The function will not be called while other 2326 * ldisc methods are in progress. 2327 */ 2328 2329 static void gsmld_close(struct tty_struct *tty) 2330 { 2331 struct gsm_mux *gsm = tty->disc_data; 2332 2333 gsmld_detach_gsm(tty, gsm); 2334 2335 gsmld_flush_buffer(tty); 2336 /* Do other clean up here */ 2337 mux_put(gsm); 2338 } 2339 2340 /** 2341 * gsmld_open - open an ldisc 2342 * @tty: terminal to open 2343 * 2344 * Called when this line discipline is being attached to the 2345 * terminal device. Can sleep. Called serialized so that no 2346 * other events will occur in parallel. No further open will occur 2347 * until a close. 2348 */ 2349 2350 static int gsmld_open(struct tty_struct *tty) 2351 { 2352 struct gsm_mux *gsm; 2353 2354 if (tty->ops->write == NULL) 2355 return -EINVAL; 2356 2357 /* Attach our ldisc data */ 2358 gsm = gsm_alloc_mux(); 2359 if (gsm == NULL) 2360 return -ENOMEM; 2361 2362 tty->disc_data = gsm; 2363 tty->receive_room = 65536; 2364 2365 /* Attach the initial passive connection */ 2366 gsm->encoding = 1; 2367 return gsmld_attach_gsm(tty, gsm); 2368 } 2369 2370 /** 2371 * gsmld_write_wakeup - asynchronous I/O notifier 2372 * @tty: tty device 2373 * 2374 * Required for the ptys, serial driver etc. since processes 2375 * that attach themselves to the master and rely on ASYNC 2376 * IO must be woken up 2377 */ 2378 2379 static void gsmld_write_wakeup(struct tty_struct *tty) 2380 { 2381 struct gsm_mux *gsm = tty->disc_data; 2382 unsigned long flags; 2383 2384 /* Queue poll */ 2385 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 2386 spin_lock_irqsave(&gsm->tx_lock, flags); 2387 gsm_data_kick(gsm); 2388 if (gsm->tx_bytes < TX_THRESH_LO) { 2389 gsm_dlci_data_sweep(gsm); 2390 } 2391 spin_unlock_irqrestore(&gsm->tx_lock, flags); 2392 } 2393 2394 /** 2395 * gsmld_read - read function for tty 2396 * @tty: tty device 2397 * @file: file object 2398 * @buf: userspace buffer pointer 2399 * @nr: size of I/O 2400 * 2401 * Perform reads for the line discipline. We are guaranteed that the 2402 * line discipline will not be closed under us but we may get multiple 2403 * parallel readers and must handle this ourselves. We may also get 2404 * a hangup. Always called in user context, may sleep. 2405 * 2406 * This code must be sure never to sleep through a hangup. 2407 */ 2408 2409 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, 2410 unsigned char __user *buf, size_t nr) 2411 { 2412 return -EOPNOTSUPP; 2413 } 2414 2415 /** 2416 * gsmld_write - write function for tty 2417 * @tty: tty device 2418 * @file: file object 2419 * @buf: userspace buffer pointer 2420 * @nr: size of I/O 2421 * 2422 * Called when the owner of the device wants to send a frame 2423 * itself (or some other control data). The data is transferred 2424 * as-is and must be properly framed and checksummed as appropriate 2425 * by userspace. Frames are either sent whole or not at all as this 2426 * avoids pain user side. 2427 */ 2428 2429 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file, 2430 const unsigned char *buf, size_t nr) 2431 { 2432 int space = tty_write_room(tty); 2433 if (space >= nr) 2434 return tty->ops->write(tty, buf, nr); 2435 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 2436 return -ENOBUFS; 2437 } 2438 2439 /** 2440 * gsmld_poll - poll method for N_GSM0710 2441 * @tty: terminal device 2442 * @file: file accessing it 2443 * @wait: poll table 2444 * 2445 * Called when the line discipline is asked to poll() for data or 2446 * for special events. This code is not serialized with respect to 2447 * other events save open/close. 2448 * 2449 * This code must be sure never to sleep through a hangup. 2450 * Called without the kernel lock held - fine 2451 */ 2452 2453 static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file, 2454 poll_table *wait) 2455 { 2456 unsigned int mask = 0; 2457 struct gsm_mux *gsm = tty->disc_data; 2458 2459 poll_wait(file, &tty->read_wait, wait); 2460 poll_wait(file, &tty->write_wait, wait); 2461 if (tty_hung_up_p(file)) 2462 mask |= POLLHUP; 2463 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0) 2464 mask |= POLLOUT | POLLWRNORM; 2465 if (gsm->dead) 2466 mask |= POLLHUP; 2467 return mask; 2468 } 2469 2470 static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm, 2471 struct gsm_config *c) 2472 { 2473 int need_close = 0; 2474 int need_restart = 0; 2475 2476 /* Stuff we don't support yet - UI or I frame transport, windowing */ 2477 if ((c->adaption != 1 && c->adaption != 2) || c->k) 2478 return -EOPNOTSUPP; 2479 /* Check the MRU/MTU range looks sane */ 2480 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8) 2481 return -EINVAL; 2482 if (c->n2 < 3) 2483 return -EINVAL; 2484 if (c->encapsulation > 1) /* Basic, advanced, no I */ 2485 return -EINVAL; 2486 if (c->initiator > 1) 2487 return -EINVAL; 2488 if (c->i == 0 || c->i > 2) /* UIH and UI only */ 2489 return -EINVAL; 2490 /* 2491 * See what is needed for reconfiguration 2492 */ 2493 2494 /* Timing fields */ 2495 if (c->t1 != 0 && c->t1 != gsm->t1) 2496 need_restart = 1; 2497 if (c->t2 != 0 && c->t2 != gsm->t2) 2498 need_restart = 1; 2499 if (c->encapsulation != gsm->encoding) 2500 need_restart = 1; 2501 if (c->adaption != gsm->adaption) 2502 need_restart = 1; 2503 /* Requires care */ 2504 if (c->initiator != gsm->initiator) 2505 need_close = 1; 2506 if (c->mru != gsm->mru) 2507 need_restart = 1; 2508 if (c->mtu != gsm->mtu) 2509 need_restart = 1; 2510 2511 /* 2512 * Close down what is needed, restart and initiate the new 2513 * configuration 2514 */ 2515 2516 if (need_close || need_restart) { 2517 gsm_dlci_begin_close(gsm->dlci[0]); 2518 /* This will timeout if the link is down due to N2 expiring */ 2519 wait_event_interruptible(gsm->event, 2520 gsm->dlci[0]->state == DLCI_CLOSED); 2521 if (signal_pending(current)) 2522 return -EINTR; 2523 } 2524 if (need_restart) 2525 gsm_cleanup_mux(gsm); 2526 2527 gsm->initiator = c->initiator; 2528 gsm->mru = c->mru; 2529 gsm->mtu = c->mtu; 2530 gsm->encoding = c->encapsulation; 2531 gsm->adaption = c->adaption; 2532 gsm->n2 = c->n2; 2533 2534 if (c->i == 1) 2535 gsm->ftype = UIH; 2536 else if (c->i == 2) 2537 gsm->ftype = UI; 2538 2539 if (c->t1) 2540 gsm->t1 = c->t1; 2541 if (c->t2) 2542 gsm->t2 = c->t2; 2543 2544 /* FIXME: We need to separate activation/deactivation from adding 2545 and removing from the mux array */ 2546 if (need_restart) 2547 gsm_activate_mux(gsm); 2548 if (gsm->initiator && need_close) 2549 gsm_dlci_begin_open(gsm->dlci[0]); 2550 return 0; 2551 } 2552 2553 static int gsmld_ioctl(struct tty_struct *tty, struct file *file, 2554 unsigned int cmd, unsigned long arg) 2555 { 2556 struct gsm_config c; 2557 struct gsm_mux *gsm = tty->disc_data; 2558 2559 switch (cmd) { 2560 case GSMIOC_GETCONF: 2561 memset(&c, 0, sizeof(c)); 2562 c.adaption = gsm->adaption; 2563 c.encapsulation = gsm->encoding; 2564 c.initiator = gsm->initiator; 2565 c.t1 = gsm->t1; 2566 c.t2 = gsm->t2; 2567 c.t3 = 0; /* Not supported */ 2568 c.n2 = gsm->n2; 2569 if (gsm->ftype == UIH) 2570 c.i = 1; 2571 else 2572 c.i = 2; 2573 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i); 2574 c.mru = gsm->mru; 2575 c.mtu = gsm->mtu; 2576 c.k = 0; 2577 if (copy_to_user((void *)arg, &c, sizeof(c))) 2578 return -EFAULT; 2579 return 0; 2580 case GSMIOC_SETCONF: 2581 if (copy_from_user(&c, (void *)arg, sizeof(c))) 2582 return -EFAULT; 2583 return gsmld_config(tty, gsm, &c); 2584 default: 2585 return n_tty_ioctl_helper(tty, file, cmd, arg); 2586 } 2587 } 2588 2589 /* 2590 * Network interface 2591 * 2592 */ 2593 2594 static int gsm_mux_net_open(struct net_device *net) 2595 { 2596 pr_debug("%s called\n", __func__); 2597 netif_start_queue(net); 2598 return 0; 2599 } 2600 2601 static int gsm_mux_net_close(struct net_device *net) 2602 { 2603 netif_stop_queue(net); 2604 return 0; 2605 } 2606 2607 static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net) 2608 { 2609 return &((struct gsm_mux_net *)netdev_priv(net))->stats; 2610 } 2611 static void dlci_net_free(struct gsm_dlci *dlci) 2612 { 2613 if (!dlci->net) { 2614 WARN_ON(1); 2615 return; 2616 } 2617 dlci->adaption = dlci->prev_adaption; 2618 dlci->data = dlci->prev_data; 2619 free_netdev(dlci->net); 2620 dlci->net = NULL; 2621 } 2622 static void net_free(struct kref *ref) 2623 { 2624 struct gsm_mux_net *mux_net; 2625 struct gsm_dlci *dlci; 2626 2627 mux_net = container_of(ref, struct gsm_mux_net, ref); 2628 dlci = mux_net->dlci; 2629 2630 if (dlci->net) { 2631 unregister_netdev(dlci->net); 2632 dlci_net_free(dlci); 2633 } 2634 } 2635 2636 static inline void muxnet_get(struct gsm_mux_net *mux_net) 2637 { 2638 kref_get(&mux_net->ref); 2639 } 2640 2641 static inline void muxnet_put(struct gsm_mux_net *mux_net) 2642 { 2643 kref_put(&mux_net->ref, net_free); 2644 } 2645 2646 static int gsm_mux_net_start_xmit(struct sk_buff *skb, 2647 struct net_device *net) 2648 { 2649 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net); 2650 struct gsm_dlci *dlci = mux_net->dlci; 2651 muxnet_get(mux_net); 2652 2653 skb_queue_head(&dlci->skb_list, skb); 2654 STATS(net).tx_packets++; 2655 STATS(net).tx_bytes += skb->len; 2656 gsm_dlci_data_kick(dlci); 2657 /* And tell the kernel when the last transmit started. */ 2658 net->trans_start = jiffies; 2659 muxnet_put(mux_net); 2660 return NETDEV_TX_OK; 2661 } 2662 2663 /* called when a packet did not ack after watchdogtimeout */ 2664 static void gsm_mux_net_tx_timeout(struct net_device *net) 2665 { 2666 /* Tell syslog we are hosed. */ 2667 dev_dbg(&net->dev, "Tx timed out.\n"); 2668 2669 /* Update statistics */ 2670 STATS(net).tx_errors++; 2671 } 2672 2673 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci, 2674 unsigned char *in_buf, int size) 2675 { 2676 struct net_device *net = dlci->net; 2677 struct sk_buff *skb; 2678 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net); 2679 muxnet_get(mux_net); 2680 2681 /* Allocate an sk_buff */ 2682 skb = dev_alloc_skb(size + NET_IP_ALIGN); 2683 if (!skb) { 2684 /* We got no receive buffer. */ 2685 STATS(net).rx_dropped++; 2686 muxnet_put(mux_net); 2687 return; 2688 } 2689 skb_reserve(skb, NET_IP_ALIGN); 2690 memcpy(skb_put(skb, size), in_buf, size); 2691 2692 skb->dev = net; 2693 skb->protocol = __constant_htons(ETH_P_IP); 2694 2695 /* Ship it off to the kernel */ 2696 netif_rx(skb); 2697 2698 /* update out statistics */ 2699 STATS(net).rx_packets++; 2700 STATS(net).rx_bytes += size; 2701 muxnet_put(mux_net); 2702 return; 2703 } 2704 2705 int gsm_change_mtu(struct net_device *net, int new_mtu) 2706 { 2707 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net); 2708 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu)) 2709 return -EINVAL; 2710 net->mtu = new_mtu; 2711 return 0; 2712 } 2713 2714 static void gsm_mux_net_init(struct net_device *net) 2715 { 2716 static const struct net_device_ops gsm_netdev_ops = { 2717 .ndo_open = gsm_mux_net_open, 2718 .ndo_stop = gsm_mux_net_close, 2719 .ndo_start_xmit = gsm_mux_net_start_xmit, 2720 .ndo_tx_timeout = gsm_mux_net_tx_timeout, 2721 .ndo_get_stats = gsm_mux_net_get_stats, 2722 .ndo_change_mtu = gsm_change_mtu, 2723 }; 2724 2725 net->netdev_ops = &gsm_netdev_ops; 2726 2727 /* fill in the other fields */ 2728 net->watchdog_timeo = GSM_NET_TX_TIMEOUT; 2729 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 2730 net->type = ARPHRD_NONE; 2731 net->tx_queue_len = 10; 2732 } 2733 2734 2735 /* caller holds the dlci mutex */ 2736 static void gsm_destroy_network(struct gsm_dlci *dlci) 2737 { 2738 struct gsm_mux_net *mux_net; 2739 2740 pr_debug("destroy network interface"); 2741 if (!dlci->net) 2742 return; 2743 mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net); 2744 muxnet_put(mux_net); 2745 } 2746 2747 2748 /* caller holds the dlci mutex */ 2749 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc) 2750 { 2751 char *netname; 2752 int retval = 0; 2753 struct net_device *net; 2754 struct gsm_mux_net *mux_net; 2755 2756 if (!capable(CAP_NET_ADMIN)) 2757 return -EPERM; 2758 2759 /* Already in a non tty mode */ 2760 if (dlci->adaption > 2) 2761 return -EBUSY; 2762 2763 if (nc->protocol != htons(ETH_P_IP)) 2764 return -EPROTONOSUPPORT; 2765 2766 if (nc->adaption != 3 && nc->adaption != 4) 2767 return -EPROTONOSUPPORT; 2768 2769 pr_debug("create network interface"); 2770 2771 netname = "gsm%d"; 2772 if (nc->if_name[0] != '\0') 2773 netname = nc->if_name; 2774 net = alloc_netdev(sizeof(struct gsm_mux_net), 2775 netname, 2776 gsm_mux_net_init); 2777 if (!net) { 2778 pr_err("alloc_netdev failed"); 2779 return -ENOMEM; 2780 } 2781 net->mtu = dlci->gsm->mtu; 2782 mux_net = (struct gsm_mux_net *)netdev_priv(net); 2783 mux_net->dlci = dlci; 2784 kref_init(&mux_net->ref); 2785 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */ 2786 2787 /* reconfigure dlci for network */ 2788 dlci->prev_adaption = dlci->adaption; 2789 dlci->prev_data = dlci->data; 2790 dlci->adaption = nc->adaption; 2791 dlci->data = gsm_mux_rx_netchar; 2792 dlci->net = net; 2793 2794 pr_debug("register netdev"); 2795 retval = register_netdev(net); 2796 if (retval) { 2797 pr_err("network register fail %d\n", retval); 2798 dlci_net_free(dlci); 2799 return retval; 2800 } 2801 return net->ifindex; /* return network index */ 2802 } 2803 2804 /* Line discipline for real tty */ 2805 struct tty_ldisc_ops tty_ldisc_packet = { 2806 .owner = THIS_MODULE, 2807 .magic = TTY_LDISC_MAGIC, 2808 .name = "n_gsm", 2809 .open = gsmld_open, 2810 .close = gsmld_close, 2811 .flush_buffer = gsmld_flush_buffer, 2812 .chars_in_buffer = gsmld_chars_in_buffer, 2813 .read = gsmld_read, 2814 .write = gsmld_write, 2815 .ioctl = gsmld_ioctl, 2816 .poll = gsmld_poll, 2817 .receive_buf = gsmld_receive_buf, 2818 .write_wakeup = gsmld_write_wakeup 2819 }; 2820 2821 /* 2822 * Virtual tty side 2823 */ 2824 2825 #define TX_SIZE 512 2826 2827 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) 2828 { 2829 u8 modembits[5]; 2830 struct gsm_control *ctrl; 2831 int len = 2; 2832 2833 if (brk) 2834 len++; 2835 2836 modembits[0] = len << 1 | EA; /* Data bytes */ 2837 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */ 2838 modembits[2] = gsm_encode_modem(dlci) << 1 | EA; 2839 if (brk) 2840 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */ 2841 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1); 2842 if (ctrl == NULL) 2843 return -ENOMEM; 2844 return gsm_control_wait(dlci->gsm, ctrl); 2845 } 2846 2847 static int gsm_carrier_raised(struct tty_port *port) 2848 { 2849 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2850 /* Not yet open so no carrier info */ 2851 if (dlci->state != DLCI_OPEN) 2852 return 0; 2853 if (debug & 2) 2854 return 1; 2855 return dlci->modem_rx & TIOCM_CD; 2856 } 2857 2858 static void gsm_dtr_rts(struct tty_port *port, int onoff) 2859 { 2860 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2861 unsigned int modem_tx = dlci->modem_tx; 2862 if (onoff) 2863 modem_tx |= TIOCM_DTR | TIOCM_RTS; 2864 else 2865 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); 2866 if (modem_tx != dlci->modem_tx) { 2867 dlci->modem_tx = modem_tx; 2868 gsmtty_modem_update(dlci, 0); 2869 } 2870 } 2871 2872 static const struct tty_port_operations gsm_port_ops = { 2873 .carrier_raised = gsm_carrier_raised, 2874 .dtr_rts = gsm_dtr_rts, 2875 .destruct = gsm_dlci_free, 2876 }; 2877 2878 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty) 2879 { 2880 struct gsm_mux *gsm; 2881 struct gsm_dlci *dlci; 2882 unsigned int line = tty->index; 2883 unsigned int mux = line >> 6; 2884 bool alloc = false; 2885 int ret; 2886 2887 line = line & 0x3F; 2888 2889 if (mux >= MAX_MUX) 2890 return -ENXIO; 2891 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */ 2892 if (gsm_mux[mux] == NULL) 2893 return -EUNATCH; 2894 if (line == 0 || line > 61) /* 62/63 reserved */ 2895 return -ECHRNG; 2896 gsm = gsm_mux[mux]; 2897 if (gsm->dead) 2898 return -EL2HLT; 2899 /* If DLCI 0 is not yet fully open return an error. This is ok from a locking 2900 perspective as we don't have to worry about this if DLCI0 is lost */ 2901 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) 2902 return -EL2NSYNC; 2903 dlci = gsm->dlci[line]; 2904 if (dlci == NULL) { 2905 alloc = true; 2906 dlci = gsm_dlci_alloc(gsm, line); 2907 } 2908 if (dlci == NULL) 2909 return -ENOMEM; 2910 ret = tty_port_install(&dlci->port, driver, tty); 2911 if (ret) { 2912 if (alloc) 2913 dlci_put(dlci); 2914 return ret; 2915 } 2916 2917 tty->driver_data = dlci; 2918 2919 return 0; 2920 } 2921 2922 static int gsmtty_open(struct tty_struct *tty, struct file *filp) 2923 { 2924 struct gsm_dlci *dlci = tty->driver_data; 2925 struct tty_port *port = &dlci->port; 2926 2927 port->count++; 2928 dlci_get(dlci); 2929 dlci_get(dlci->gsm->dlci[0]); 2930 mux_get(dlci->gsm); 2931 tty_port_tty_set(port, tty); 2932 2933 dlci->modem_rx = 0; 2934 /* We could in theory open and close before we wait - eg if we get 2935 a DM straight back. This is ok as that will have caused a hangup */ 2936 set_bit(ASYNCB_INITIALIZED, &port->flags); 2937 /* Start sending off SABM messages */ 2938 gsm_dlci_begin_open(dlci); 2939 /* And wait for virtual carrier */ 2940 return tty_port_block_til_ready(port, tty, filp); 2941 } 2942 2943 static void gsmtty_close(struct tty_struct *tty, struct file *filp) 2944 { 2945 struct gsm_dlci *dlci = tty->driver_data; 2946 struct gsm_mux *gsm; 2947 2948 if (dlci == NULL) 2949 return; 2950 mutex_lock(&dlci->mutex); 2951 gsm_destroy_network(dlci); 2952 mutex_unlock(&dlci->mutex); 2953 gsm = dlci->gsm; 2954 if (tty_port_close_start(&dlci->port, tty, filp) == 0) 2955 goto out; 2956 gsm_dlci_begin_close(dlci); 2957 tty_port_close_end(&dlci->port, tty); 2958 tty_port_tty_set(&dlci->port, NULL); 2959 out: 2960 dlci_put(dlci); 2961 dlci_put(gsm->dlci[0]); 2962 mux_put(gsm); 2963 } 2964 2965 static void gsmtty_hangup(struct tty_struct *tty) 2966 { 2967 struct gsm_dlci *dlci = tty->driver_data; 2968 tty_port_hangup(&dlci->port); 2969 gsm_dlci_begin_close(dlci); 2970 } 2971 2972 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf, 2973 int len) 2974 { 2975 struct gsm_dlci *dlci = tty->driver_data; 2976 /* Stuff the bytes into the fifo queue */ 2977 int sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock); 2978 /* Need to kick the channel */ 2979 gsm_dlci_data_kick(dlci); 2980 return sent; 2981 } 2982 2983 static int gsmtty_write_room(struct tty_struct *tty) 2984 { 2985 struct gsm_dlci *dlci = tty->driver_data; 2986 return TX_SIZE - kfifo_len(dlci->fifo); 2987 } 2988 2989 static int gsmtty_chars_in_buffer(struct tty_struct *tty) 2990 { 2991 struct gsm_dlci *dlci = tty->driver_data; 2992 return kfifo_len(dlci->fifo); 2993 } 2994 2995 static void gsmtty_flush_buffer(struct tty_struct *tty) 2996 { 2997 struct gsm_dlci *dlci = tty->driver_data; 2998 /* Caution needed: If we implement reliable transport classes 2999 then the data being transmitted can't simply be junked once 3000 it has first hit the stack. Until then we can just blow it 3001 away */ 3002 kfifo_reset(dlci->fifo); 3003 /* Need to unhook this DLCI from the transmit queue logic */ 3004 } 3005 3006 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout) 3007 { 3008 /* The FIFO handles the queue so the kernel will do the right 3009 thing waiting on chars_in_buffer before calling us. No work 3010 to do here */ 3011 } 3012 3013 static int gsmtty_tiocmget(struct tty_struct *tty) 3014 { 3015 struct gsm_dlci *dlci = tty->driver_data; 3016 return dlci->modem_rx; 3017 } 3018 3019 static int gsmtty_tiocmset(struct tty_struct *tty, 3020 unsigned int set, unsigned int clear) 3021 { 3022 struct gsm_dlci *dlci = tty->driver_data; 3023 unsigned int modem_tx = dlci->modem_tx; 3024 3025 modem_tx &= ~clear; 3026 modem_tx |= set; 3027 3028 if (modem_tx != dlci->modem_tx) { 3029 dlci->modem_tx = modem_tx; 3030 return gsmtty_modem_update(dlci, 0); 3031 } 3032 return 0; 3033 } 3034 3035 3036 static int gsmtty_ioctl(struct tty_struct *tty, 3037 unsigned int cmd, unsigned long arg) 3038 { 3039 struct gsm_dlci *dlci = tty->driver_data; 3040 struct gsm_netconfig nc; 3041 int index; 3042 3043 switch (cmd) { 3044 case GSMIOC_ENABLE_NET: 3045 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc))) 3046 return -EFAULT; 3047 nc.if_name[IFNAMSIZ-1] = '\0'; 3048 /* return net interface index or error code */ 3049 mutex_lock(&dlci->mutex); 3050 index = gsm_create_network(dlci, &nc); 3051 mutex_unlock(&dlci->mutex); 3052 if (copy_to_user((void __user *)arg, &nc, sizeof(nc))) 3053 return -EFAULT; 3054 return index; 3055 case GSMIOC_DISABLE_NET: 3056 if (!capable(CAP_NET_ADMIN)) 3057 return -EPERM; 3058 mutex_lock(&dlci->mutex); 3059 gsm_destroy_network(dlci); 3060 mutex_unlock(&dlci->mutex); 3061 return 0; 3062 default: 3063 return -ENOIOCTLCMD; 3064 } 3065 } 3066 3067 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old) 3068 { 3069 /* For the moment its fixed. In actual fact the speed information 3070 for the virtual channel can be propogated in both directions by 3071 the RPN control message. This however rapidly gets nasty as we 3072 then have to remap modem signals each way according to whether 3073 our virtual cable is null modem etc .. */ 3074 tty_termios_copy_hw(&tty->termios, old); 3075 } 3076 3077 static void gsmtty_throttle(struct tty_struct *tty) 3078 { 3079 struct gsm_dlci *dlci = tty->driver_data; 3080 if (tty->termios.c_cflag & CRTSCTS) 3081 dlci->modem_tx &= ~TIOCM_DTR; 3082 dlci->throttled = 1; 3083 /* Send an MSC with DTR cleared */ 3084 gsmtty_modem_update(dlci, 0); 3085 } 3086 3087 static void gsmtty_unthrottle(struct tty_struct *tty) 3088 { 3089 struct gsm_dlci *dlci = tty->driver_data; 3090 if (tty->termios.c_cflag & CRTSCTS) 3091 dlci->modem_tx |= TIOCM_DTR; 3092 dlci->throttled = 0; 3093 /* Send an MSC with DTR set */ 3094 gsmtty_modem_update(dlci, 0); 3095 } 3096 3097 static int gsmtty_break_ctl(struct tty_struct *tty, int state) 3098 { 3099 struct gsm_dlci *dlci = tty->driver_data; 3100 int encode = 0; /* Off */ 3101 3102 if (state == -1) /* "On indefinitely" - we can't encode this 3103 properly */ 3104 encode = 0x0F; 3105 else if (state > 0) { 3106 encode = state / 200; /* mS to encoding */ 3107 if (encode > 0x0F) 3108 encode = 0x0F; /* Best effort */ 3109 } 3110 return gsmtty_modem_update(dlci, encode); 3111 } 3112 3113 3114 /* Virtual ttys for the demux */ 3115 static const struct tty_operations gsmtty_ops = { 3116 .install = gsmtty_install, 3117 .open = gsmtty_open, 3118 .close = gsmtty_close, 3119 .write = gsmtty_write, 3120 .write_room = gsmtty_write_room, 3121 .chars_in_buffer = gsmtty_chars_in_buffer, 3122 .flush_buffer = gsmtty_flush_buffer, 3123 .ioctl = gsmtty_ioctl, 3124 .throttle = gsmtty_throttle, 3125 .unthrottle = gsmtty_unthrottle, 3126 .set_termios = gsmtty_set_termios, 3127 .hangup = gsmtty_hangup, 3128 .wait_until_sent = gsmtty_wait_until_sent, 3129 .tiocmget = gsmtty_tiocmget, 3130 .tiocmset = gsmtty_tiocmset, 3131 .break_ctl = gsmtty_break_ctl, 3132 }; 3133 3134 3135 3136 static int __init gsm_init(void) 3137 { 3138 /* Fill in our line protocol discipline, and register it */ 3139 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet); 3140 if (status != 0) { 3141 pr_err("n_gsm: can't register line discipline (err = %d)\n", 3142 status); 3143 return status; 3144 } 3145 3146 gsm_tty_driver = alloc_tty_driver(256); 3147 if (!gsm_tty_driver) { 3148 tty_unregister_ldisc(N_GSM0710); 3149 pr_err("gsm_init: tty allocation failed.\n"); 3150 return -EINVAL; 3151 } 3152 gsm_tty_driver->driver_name = "gsmtty"; 3153 gsm_tty_driver->name = "gsmtty"; 3154 gsm_tty_driver->major = 0; /* Dynamic */ 3155 gsm_tty_driver->minor_start = 0; 3156 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; 3157 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL; 3158 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV 3159 | TTY_DRIVER_HARDWARE_BREAK; 3160 gsm_tty_driver->init_termios = tty_std_termios; 3161 /* Fixme */ 3162 gsm_tty_driver->init_termios.c_lflag &= ~ECHO; 3163 tty_set_operations(gsm_tty_driver, &gsmtty_ops); 3164 3165 spin_lock_init(&gsm_mux_lock); 3166 3167 if (tty_register_driver(gsm_tty_driver)) { 3168 put_tty_driver(gsm_tty_driver); 3169 tty_unregister_ldisc(N_GSM0710); 3170 pr_err("gsm_init: tty registration failed.\n"); 3171 return -EBUSY; 3172 } 3173 pr_debug("gsm_init: loaded as %d,%d.\n", 3174 gsm_tty_driver->major, gsm_tty_driver->minor_start); 3175 return 0; 3176 } 3177 3178 static void __exit gsm_exit(void) 3179 { 3180 int status = tty_unregister_ldisc(N_GSM0710); 3181 if (status != 0) 3182 pr_err("n_gsm: can't unregister line discipline (err = %d)\n", 3183 status); 3184 tty_unregister_driver(gsm_tty_driver); 3185 put_tty_driver(gsm_tty_driver); 3186 } 3187 3188 module_init(gsm_init); 3189 module_exit(gsm_exit); 3190 3191 3192 MODULE_LICENSE("GPL"); 3193 MODULE_ALIAS_LDISC(N_GSM0710); 3194