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 kref ref; /* freed from port or mux close */ 138 struct mutex mutex; 139 140 /* Link layer */ 141 spinlock_t lock; /* Protects the internal state */ 142 struct timer_list t1; /* Retransmit timer for SABM and UA */ 143 int retries; 144 /* Uplink tty if active */ 145 struct tty_port port; /* The tty bound to this DLCI if there is one */ 146 struct kfifo *fifo; /* Queue fifo for the DLCI */ 147 struct kfifo _fifo; /* For new fifo API porting only */ 148 int adaption; /* Adaption layer in use */ 149 int prev_adaption; 150 u32 modem_rx; /* Our incoming virtual modem lines */ 151 u32 modem_tx; /* Our outgoing modem lines */ 152 int dead; /* Refuse re-open */ 153 /* Flow control */ 154 int throttled; /* Private copy of throttle state */ 155 int constipated; /* Throttle status for outgoing */ 156 /* Packetised I/O */ 157 struct sk_buff *skb; /* Frame being sent */ 158 struct sk_buff_head skb_list; /* Queued frames */ 159 /* Data handling callback */ 160 void (*data)(struct gsm_dlci *dlci, u8 *data, int len); 161 void (*prev_data)(struct gsm_dlci *dlci, u8 *data, int len); 162 struct net_device *net; /* network interface, if created */ 163 }; 164 165 /* DLCI 0, 62/63 are special or reseved see gsmtty_open */ 166 167 #define NUM_DLCI 64 168 169 /* 170 * DLCI 0 is used to pass control blocks out of band of the data 171 * flow (and with a higher link priority). One command can be outstanding 172 * at a time and we use this structure to manage them. They are created 173 * and destroyed by the user context, and updated by the receive paths 174 * and timers 175 */ 176 177 struct gsm_control { 178 u8 cmd; /* Command we are issuing */ 179 u8 *data; /* Data for the command in case we retransmit */ 180 int len; /* Length of block for retransmission */ 181 int done; /* Done flag */ 182 int error; /* Error if any */ 183 }; 184 185 /* 186 * Each GSM mux we have is represented by this structure. If we are 187 * operating as an ldisc then we use this structure as our ldisc 188 * state. We need to sort out lifetimes and locking with respect 189 * to the gsm mux array. For now we don't free DLCI objects that 190 * have been instantiated until the mux itself is terminated. 191 * 192 * To consider further: tty open versus mux shutdown. 193 */ 194 195 struct gsm_mux { 196 struct tty_struct *tty; /* The tty our ldisc is bound to */ 197 spinlock_t lock; 198 unsigned int num; 199 struct kref ref; 200 201 /* Events on the GSM channel */ 202 wait_queue_head_t event; 203 204 /* Bits for GSM mode decoding */ 205 206 /* Framing Layer */ 207 unsigned char *buf; 208 int state; 209 #define GSM_SEARCH 0 210 #define GSM_START 1 211 #define GSM_ADDRESS 2 212 #define GSM_CONTROL 3 213 #define GSM_LEN 4 214 #define GSM_DATA 5 215 #define GSM_FCS 6 216 #define GSM_OVERRUN 7 217 #define GSM_LEN0 8 218 #define GSM_LEN1 9 219 #define GSM_SSOF 10 220 unsigned int len; 221 unsigned int address; 222 unsigned int count; 223 int escape; 224 int encoding; 225 u8 control; 226 u8 fcs; 227 u8 received_fcs; 228 u8 *txframe; /* TX framing buffer */ 229 230 /* Methods for the receiver side */ 231 void (*receive)(struct gsm_mux *gsm, u8 ch); 232 void (*error)(struct gsm_mux *gsm, u8 ch, u8 flag); 233 /* And transmit side */ 234 int (*output)(struct gsm_mux *mux, u8 *data, int len); 235 236 /* Link Layer */ 237 unsigned int mru; 238 unsigned int mtu; 239 int initiator; /* Did we initiate connection */ 240 int dead; /* Has the mux been shut down */ 241 struct gsm_dlci *dlci[NUM_DLCI]; 242 int constipated; /* Asked by remote to shut up */ 243 244 spinlock_t tx_lock; 245 unsigned int tx_bytes; /* TX data outstanding */ 246 #define TX_THRESH_HI 8192 247 #define TX_THRESH_LO 2048 248 struct 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. Always one byte as we never 832 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 if (brk & 0x01) 1072 tty_insert_flip_char(tty, 0, TTY_BREAK); 1073 } 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_struct *tty; 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 /* See if we have an uplink tty */ 1165 tty = tty_port_tty_get(&gsm->dlci[addr]->port); 1166 1167 if (tty) { 1168 if (bits & 2) 1169 tty_insert_flip_char(tty, 0, TTY_OVERRUN); 1170 if (bits & 4) 1171 tty_insert_flip_char(tty, 0, TTY_PARITY); 1172 if (bits & 8) 1173 tty_insert_flip_char(tty, 0, TTY_FRAME); 1174 tty_flip_buffer_push(tty); 1175 tty_kref_put(tty); 1176 } 1177 gsm_control_reply(gsm, CMD_RLS, data, clen); 1178 } 1179 1180 static void gsm_dlci_begin_close(struct gsm_dlci *dlci); 1181 1182 /** 1183 * gsm_control_message - DLCI 0 control processing 1184 * @gsm: our GSM mux 1185 * @command: the command EA 1186 * @data: data beyond the command/length EAs 1187 * @clen: length 1188 * 1189 * Input processor for control messages from the other end of the link. 1190 * Processes the incoming request and queues a response frame or an 1191 * NSC response if not supported 1192 */ 1193 1194 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, 1195 u8 *data, int clen) 1196 { 1197 u8 buf[1]; 1198 unsigned long flags; 1199 1200 switch (command) { 1201 case CMD_CLD: { 1202 struct gsm_dlci *dlci = gsm->dlci[0]; 1203 /* Modem wishes to close down */ 1204 if (dlci) { 1205 dlci->dead = 1; 1206 gsm->dead = 1; 1207 gsm_dlci_begin_close(dlci); 1208 } 1209 } 1210 break; 1211 case CMD_TEST: 1212 /* Modem wishes to test, reply with the data */ 1213 gsm_control_reply(gsm, CMD_TEST, data, clen); 1214 break; 1215 case CMD_FCON: 1216 /* Modem can accept data again */ 1217 gsm->constipated = 0; 1218 gsm_control_reply(gsm, CMD_FCON, NULL, 0); 1219 /* Kick the link in case it is idling */ 1220 spin_lock_irqsave(&gsm->tx_lock, flags); 1221 gsm_data_kick(gsm); 1222 spin_unlock_irqrestore(&gsm->tx_lock, flags); 1223 break; 1224 case CMD_FCOFF: 1225 /* Modem wants us to STFU */ 1226 gsm->constipated = 1; 1227 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0); 1228 break; 1229 case CMD_MSC: 1230 /* Out of band modem line change indicator for a DLCI */ 1231 gsm_control_modem(gsm, data, clen); 1232 break; 1233 case CMD_RLS: 1234 /* Out of band error reception for a DLCI */ 1235 gsm_control_rls(gsm, data, clen); 1236 break; 1237 case CMD_PSC: 1238 /* Modem wishes to enter power saving state */ 1239 gsm_control_reply(gsm, CMD_PSC, NULL, 0); 1240 break; 1241 /* Optional unsupported commands */ 1242 case CMD_PN: /* Parameter negotiation */ 1243 case CMD_RPN: /* Remote port negotiation */ 1244 case CMD_SNC: /* Service negotiation command */ 1245 default: 1246 /* Reply to bad commands with an NSC */ 1247 buf[0] = command; 1248 gsm_control_reply(gsm, CMD_NSC, buf, 1); 1249 break; 1250 } 1251 } 1252 1253 /** 1254 * gsm_control_response - process a response to our control 1255 * @gsm: our GSM mux 1256 * @command: the command (response) EA 1257 * @data: data beyond the command/length EA 1258 * @clen: length 1259 * 1260 * Process a response to an outstanding command. We only allow a single 1261 * control message in flight so this is fairly easy. All the clean up 1262 * is done by the caller, we just update the fields, flag it as done 1263 * and return 1264 */ 1265 1266 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command, 1267 u8 *data, int clen) 1268 { 1269 struct gsm_control *ctrl; 1270 unsigned long flags; 1271 1272 spin_lock_irqsave(&gsm->control_lock, flags); 1273 1274 ctrl = gsm->pending_cmd; 1275 /* Does the reply match our command */ 1276 command |= 1; 1277 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) { 1278 /* Our command was replied to, kill the retry timer */ 1279 del_timer(&gsm->t2_timer); 1280 gsm->pending_cmd = NULL; 1281 /* Rejected by the other end */ 1282 if (command == CMD_NSC) 1283 ctrl->error = -EOPNOTSUPP; 1284 ctrl->done = 1; 1285 wake_up(&gsm->event); 1286 } 1287 spin_unlock_irqrestore(&gsm->control_lock, flags); 1288 } 1289 1290 /** 1291 * gsm_control_transmit - send control packet 1292 * @gsm: gsm mux 1293 * @ctrl: frame to send 1294 * 1295 * Send out a pending control command (called under control lock) 1296 */ 1297 1298 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl) 1299 { 1300 struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype); 1301 if (msg == NULL) 1302 return; 1303 msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */ 1304 memcpy(msg->data + 1, ctrl->data, ctrl->len); 1305 gsm_data_queue(gsm->dlci[0], msg); 1306 } 1307 1308 /** 1309 * gsm_control_retransmit - retransmit a control frame 1310 * @data: pointer to our gsm object 1311 * 1312 * Called off the T2 timer expiry in order to retransmit control frames 1313 * that have been lost in the system somewhere. The control_lock protects 1314 * us from colliding with another sender or a receive completion event. 1315 * In that situation the timer may still occur in a small window but 1316 * gsm->pending_cmd will be NULL and we just let the timer expire. 1317 */ 1318 1319 static void gsm_control_retransmit(unsigned long data) 1320 { 1321 struct gsm_mux *gsm = (struct gsm_mux *)data; 1322 struct gsm_control *ctrl; 1323 unsigned long flags; 1324 spin_lock_irqsave(&gsm->control_lock, flags); 1325 ctrl = gsm->pending_cmd; 1326 if (ctrl) { 1327 gsm->cretries--; 1328 if (gsm->cretries == 0) { 1329 gsm->pending_cmd = NULL; 1330 ctrl->error = -ETIMEDOUT; 1331 ctrl->done = 1; 1332 spin_unlock_irqrestore(&gsm->control_lock, flags); 1333 wake_up(&gsm->event); 1334 return; 1335 } 1336 gsm_control_transmit(gsm, ctrl); 1337 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); 1338 } 1339 spin_unlock_irqrestore(&gsm->control_lock, flags); 1340 } 1341 1342 /** 1343 * gsm_control_send - send a control frame on DLCI 0 1344 * @gsm: the GSM channel 1345 * @command: command to send including CR bit 1346 * @data: bytes of data (must be kmalloced) 1347 * @len: length of the block to send 1348 * 1349 * Queue and dispatch a control command. Only one command can be 1350 * active at a time. In theory more can be outstanding but the matching 1351 * gets really complicated so for now stick to one outstanding. 1352 */ 1353 1354 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm, 1355 unsigned int command, u8 *data, int clen) 1356 { 1357 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control), 1358 GFP_KERNEL); 1359 unsigned long flags; 1360 if (ctrl == NULL) 1361 return NULL; 1362 retry: 1363 wait_event(gsm->event, gsm->pending_cmd == NULL); 1364 spin_lock_irqsave(&gsm->control_lock, flags); 1365 if (gsm->pending_cmd != NULL) { 1366 spin_unlock_irqrestore(&gsm->control_lock, flags); 1367 goto retry; 1368 } 1369 ctrl->cmd = command; 1370 ctrl->data = data; 1371 ctrl->len = clen; 1372 gsm->pending_cmd = ctrl; 1373 gsm->cretries = gsm->n2; 1374 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); 1375 gsm_control_transmit(gsm, ctrl); 1376 spin_unlock_irqrestore(&gsm->control_lock, flags); 1377 return ctrl; 1378 } 1379 1380 /** 1381 * gsm_control_wait - wait for a control to finish 1382 * @gsm: GSM mux 1383 * @control: control we are waiting on 1384 * 1385 * Waits for the control to complete or time out. Frees any used 1386 * resources and returns 0 for success, or an error if the remote 1387 * rejected or ignored the request. 1388 */ 1389 1390 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control) 1391 { 1392 int err; 1393 wait_event(gsm->event, control->done == 1); 1394 err = control->error; 1395 kfree(control); 1396 return err; 1397 } 1398 1399 1400 /* 1401 * DLCI level handling: Needs krefs 1402 */ 1403 1404 /* 1405 * State transitions and timers 1406 */ 1407 1408 /** 1409 * gsm_dlci_close - a DLCI has closed 1410 * @dlci: DLCI that closed 1411 * 1412 * Perform processing when moving a DLCI into closed state. If there 1413 * is an attached tty this is hung up 1414 */ 1415 1416 static void gsm_dlci_close(struct gsm_dlci *dlci) 1417 { 1418 del_timer(&dlci->t1); 1419 if (debug & 8) 1420 pr_debug("DLCI %d goes closed.\n", dlci->addr); 1421 dlci->state = DLCI_CLOSED; 1422 if (dlci->addr != 0) { 1423 struct tty_struct *tty = tty_port_tty_get(&dlci->port); 1424 if (tty) { 1425 tty_hangup(tty); 1426 tty_kref_put(tty); 1427 } 1428 kfifo_reset(dlci->fifo); 1429 } else 1430 dlci->gsm->dead = 1; 1431 wake_up(&dlci->gsm->event); 1432 /* A DLCI 0 close is a MUX termination so we need to kick that 1433 back to userspace somehow */ 1434 } 1435 1436 /** 1437 * gsm_dlci_open - a DLCI has opened 1438 * @dlci: DLCI that opened 1439 * 1440 * Perform processing when moving a DLCI into open state. 1441 */ 1442 1443 static void gsm_dlci_open(struct gsm_dlci *dlci) 1444 { 1445 /* Note that SABM UA .. SABM UA first UA lost can mean that we go 1446 open -> open */ 1447 del_timer(&dlci->t1); 1448 /* This will let a tty open continue */ 1449 dlci->state = DLCI_OPEN; 1450 if (debug & 8) 1451 pr_debug("DLCI %d goes open.\n", dlci->addr); 1452 wake_up(&dlci->gsm->event); 1453 } 1454 1455 /** 1456 * gsm_dlci_t1 - T1 timer expiry 1457 * @dlci: DLCI that opened 1458 * 1459 * The T1 timer handles retransmits of control frames (essentially of 1460 * SABM and DISC). We resend the command until the retry count runs out 1461 * in which case an opening port goes back to closed and a closing port 1462 * is simply put into closed state (any further frames from the other 1463 * end will get a DM response) 1464 */ 1465 1466 static void gsm_dlci_t1(unsigned long data) 1467 { 1468 struct gsm_dlci *dlci = (struct gsm_dlci *)data; 1469 struct gsm_mux *gsm = dlci->gsm; 1470 1471 switch (dlci->state) { 1472 case DLCI_OPENING: 1473 dlci->retries--; 1474 if (dlci->retries) { 1475 gsm_command(dlci->gsm, dlci->addr, SABM|PF); 1476 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1477 } else 1478 gsm_dlci_close(dlci); 1479 break; 1480 case DLCI_CLOSING: 1481 dlci->retries--; 1482 if (dlci->retries) { 1483 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 1484 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1485 } else 1486 gsm_dlci_close(dlci); 1487 break; 1488 } 1489 } 1490 1491 /** 1492 * gsm_dlci_begin_open - start channel open procedure 1493 * @dlci: DLCI to open 1494 * 1495 * Commence opening a DLCI from the Linux side. We issue SABM messages 1496 * to the modem which should then reply with a UA, at which point we 1497 * will move into open state. Opening is done asynchronously with retry 1498 * running off timers and the responses. 1499 */ 1500 1501 static void gsm_dlci_begin_open(struct gsm_dlci *dlci) 1502 { 1503 struct gsm_mux *gsm = dlci->gsm; 1504 if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING) 1505 return; 1506 dlci->retries = gsm->n2; 1507 dlci->state = DLCI_OPENING; 1508 gsm_command(dlci->gsm, dlci->addr, SABM|PF); 1509 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1510 } 1511 1512 /** 1513 * gsm_dlci_begin_close - start channel open procedure 1514 * @dlci: DLCI to open 1515 * 1516 * Commence closing a DLCI from the Linux side. We issue DISC messages 1517 * to the modem which should then reply with a UA, at which point we 1518 * will move into closed state. Closing is done asynchronously with retry 1519 * off timers. We may also receive a DM reply from the other end which 1520 * indicates the channel was already closed. 1521 */ 1522 1523 static void gsm_dlci_begin_close(struct gsm_dlci *dlci) 1524 { 1525 struct gsm_mux *gsm = dlci->gsm; 1526 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING) 1527 return; 1528 dlci->retries = gsm->n2; 1529 dlci->state = DLCI_CLOSING; 1530 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 1531 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1532 } 1533 1534 /** 1535 * gsm_dlci_data - data arrived 1536 * @dlci: channel 1537 * @data: block of bytes received 1538 * @len: length of received block 1539 * 1540 * A UI or UIH frame has arrived which contains data for a channel 1541 * other than the control channel. If the relevant virtual tty is 1542 * open we shovel the bits down it, if not we drop them. 1543 */ 1544 1545 static void gsm_dlci_data(struct gsm_dlci *dlci, u8 *data, int clen) 1546 { 1547 /* krefs .. */ 1548 struct tty_port *port = &dlci->port; 1549 struct tty_struct *tty = tty_port_tty_get(port); 1550 unsigned int modem = 0; 1551 int len = clen; 1552 1553 if (debug & 16) 1554 pr_debug("%d bytes for tty %p\n", len, tty); 1555 if (tty) { 1556 switch (dlci->adaption) { 1557 /* Unsupported types */ 1558 /* Packetised interruptible data */ 1559 case 4: 1560 break; 1561 /* Packetised uininterruptible voice/data */ 1562 case 3: 1563 break; 1564 /* Asynchronous serial with line state in each frame */ 1565 case 2: 1566 while (gsm_read_ea(&modem, *data++) == 0) { 1567 len--; 1568 if (len == 0) 1569 return; 1570 } 1571 gsm_process_modem(tty, dlci, modem, clen); 1572 /* Line state will go via DLCI 0 controls only */ 1573 case 1: 1574 default: 1575 tty_insert_flip_string(tty, data, len); 1576 tty_flip_buffer_push(tty); 1577 } 1578 tty_kref_put(tty); 1579 } 1580 } 1581 1582 /** 1583 * gsm_dlci_control - data arrived on control channel 1584 * @dlci: channel 1585 * @data: block of bytes received 1586 * @len: length of received block 1587 * 1588 * A UI or UIH frame has arrived which contains data for DLCI 0 the 1589 * control channel. This should contain a command EA followed by 1590 * control data bytes. The command EA contains a command/response bit 1591 * and we divide up the work accordingly. 1592 */ 1593 1594 static void gsm_dlci_command(struct gsm_dlci *dlci, u8 *data, int len) 1595 { 1596 /* See what command is involved */ 1597 unsigned int command = 0; 1598 while (len-- > 0) { 1599 if (gsm_read_ea(&command, *data++) == 1) { 1600 int clen = *data++; 1601 len--; 1602 /* FIXME: this is properly an EA */ 1603 clen >>= 1; 1604 /* Malformed command ? */ 1605 if (clen > len) 1606 return; 1607 if (command & 1) 1608 gsm_control_message(dlci->gsm, command, 1609 data, clen); 1610 else 1611 gsm_control_response(dlci->gsm, command, 1612 data, clen); 1613 return; 1614 } 1615 } 1616 } 1617 1618 /* 1619 * Allocate/Free DLCI channels 1620 */ 1621 1622 /** 1623 * gsm_dlci_alloc - allocate a DLCI 1624 * @gsm: GSM mux 1625 * @addr: address of the DLCI 1626 * 1627 * Allocate and install a new DLCI object into the GSM mux. 1628 * 1629 * FIXME: review locking races 1630 */ 1631 1632 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr) 1633 { 1634 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC); 1635 if (dlci == NULL) 1636 return NULL; 1637 spin_lock_init(&dlci->lock); 1638 kref_init(&dlci->ref); 1639 mutex_init(&dlci->mutex); 1640 dlci->fifo = &dlci->_fifo; 1641 if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) { 1642 kfree(dlci); 1643 return NULL; 1644 } 1645 1646 skb_queue_head_init(&dlci->skb_list); 1647 init_timer(&dlci->t1); 1648 dlci->t1.function = gsm_dlci_t1; 1649 dlci->t1.data = (unsigned long)dlci; 1650 tty_port_init(&dlci->port); 1651 dlci->port.ops = &gsm_port_ops; 1652 dlci->gsm = gsm; 1653 dlci->addr = addr; 1654 dlci->adaption = gsm->adaption; 1655 dlci->state = DLCI_CLOSED; 1656 if (addr) 1657 dlci->data = gsm_dlci_data; 1658 else 1659 dlci->data = gsm_dlci_command; 1660 gsm->dlci[addr] = dlci; 1661 return dlci; 1662 } 1663 1664 /** 1665 * gsm_dlci_free - free DLCI 1666 * @dlci: DLCI to free 1667 * 1668 * Free up a DLCI. 1669 * 1670 * Can sleep. 1671 */ 1672 static void gsm_dlci_free(struct kref *ref) 1673 { 1674 struct gsm_dlci *dlci = container_of(ref, struct gsm_dlci, ref); 1675 1676 del_timer_sync(&dlci->t1); 1677 dlci->gsm->dlci[dlci->addr] = NULL; 1678 kfifo_free(dlci->fifo); 1679 while ((dlci->skb = skb_dequeue(&dlci->skb_list))) 1680 dev_kfree_skb(dlci->skb); 1681 kfree(dlci); 1682 } 1683 1684 static inline void dlci_get(struct gsm_dlci *dlci) 1685 { 1686 kref_get(&dlci->ref); 1687 } 1688 1689 static inline void dlci_put(struct gsm_dlci *dlci) 1690 { 1691 kref_put(&dlci->ref, gsm_dlci_free); 1692 } 1693 1694 /** 1695 * gsm_dlci_release - release DLCI 1696 * @dlci: DLCI to destroy 1697 * 1698 * Release a DLCI. Actual free is deferred until either 1699 * mux is closed or tty is closed - whichever is last. 1700 * 1701 * Can sleep. 1702 */ 1703 static void gsm_dlci_release(struct gsm_dlci *dlci) 1704 { 1705 struct tty_struct *tty = tty_port_tty_get(&dlci->port); 1706 if (tty) { 1707 tty_vhangup(tty); 1708 tty_kref_put(tty); 1709 } 1710 dlci_put(dlci); 1711 } 1712 1713 /* 1714 * LAPBish link layer logic 1715 */ 1716 1717 /** 1718 * gsm_queue - a GSM frame is ready to process 1719 * @gsm: pointer to our gsm mux 1720 * 1721 * At this point in time a frame has arrived and been demangled from 1722 * the line encoding. All the differences between the encodings have 1723 * been handled below us and the frame is unpacked into the structures. 1724 * The fcs holds the header FCS but any data FCS must be added here. 1725 */ 1726 1727 static void gsm_queue(struct gsm_mux *gsm) 1728 { 1729 struct gsm_dlci *dlci; 1730 u8 cr; 1731 int address; 1732 /* We have to sneak a look at the packet body to do the FCS. 1733 A somewhat layering violation in the spec */ 1734 1735 if ((gsm->control & ~PF) == UI) 1736 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len); 1737 if (gsm->encoding == 0){ 1738 /* WARNING: gsm->received_fcs is used for gsm->encoding = 0 only. 1739 In this case it contain the last piece of data 1740 required to generate final CRC */ 1741 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs); 1742 } 1743 if (gsm->fcs != GOOD_FCS) { 1744 gsm->bad_fcs++; 1745 if (debug & 4) 1746 pr_debug("BAD FCS %02x\n", gsm->fcs); 1747 return; 1748 } 1749 address = gsm->address >> 1; 1750 if (address >= NUM_DLCI) 1751 goto invalid; 1752 1753 cr = gsm->address & 1; /* C/R bit */ 1754 1755 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len); 1756 1757 cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */ 1758 dlci = gsm->dlci[address]; 1759 1760 switch (gsm->control) { 1761 case SABM|PF: 1762 if (cr == 0) 1763 goto invalid; 1764 if (dlci == NULL) 1765 dlci = gsm_dlci_alloc(gsm, address); 1766 if (dlci == NULL) 1767 return; 1768 if (dlci->dead) 1769 gsm_response(gsm, address, DM); 1770 else { 1771 gsm_response(gsm, address, UA); 1772 gsm_dlci_open(dlci); 1773 } 1774 break; 1775 case DISC|PF: 1776 if (cr == 0) 1777 goto invalid; 1778 if (dlci == NULL || dlci->state == DLCI_CLOSED) { 1779 gsm_response(gsm, address, DM); 1780 return; 1781 } 1782 /* Real close complete */ 1783 gsm_response(gsm, address, UA); 1784 gsm_dlci_close(dlci); 1785 break; 1786 case UA: 1787 case UA|PF: 1788 if (cr == 0 || dlci == NULL) 1789 break; 1790 switch (dlci->state) { 1791 case DLCI_CLOSING: 1792 gsm_dlci_close(dlci); 1793 break; 1794 case DLCI_OPENING: 1795 gsm_dlci_open(dlci); 1796 break; 1797 } 1798 break; 1799 case DM: /* DM can be valid unsolicited */ 1800 case DM|PF: 1801 if (cr) 1802 goto invalid; 1803 if (dlci == NULL) 1804 return; 1805 gsm_dlci_close(dlci); 1806 break; 1807 case UI: 1808 case UI|PF: 1809 case UIH: 1810 case UIH|PF: 1811 #if 0 1812 if (cr) 1813 goto invalid; 1814 #endif 1815 if (dlci == NULL || dlci->state != DLCI_OPEN) { 1816 gsm_command(gsm, address, DM|PF); 1817 return; 1818 } 1819 dlci->data(dlci, gsm->buf, gsm->len); 1820 break; 1821 default: 1822 goto invalid; 1823 } 1824 return; 1825 invalid: 1826 gsm->malformed++; 1827 return; 1828 } 1829 1830 1831 /** 1832 * gsm0_receive - perform processing for non-transparency 1833 * @gsm: gsm data for this ldisc instance 1834 * @c: character 1835 * 1836 * Receive bytes in gsm mode 0 1837 */ 1838 1839 static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) 1840 { 1841 unsigned int len; 1842 1843 switch (gsm->state) { 1844 case GSM_SEARCH: /* SOF marker */ 1845 if (c == GSM0_SOF) { 1846 gsm->state = GSM_ADDRESS; 1847 gsm->address = 0; 1848 gsm->len = 0; 1849 gsm->fcs = INIT_FCS; 1850 } 1851 break; 1852 case GSM_ADDRESS: /* Address EA */ 1853 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1854 if (gsm_read_ea(&gsm->address, c)) 1855 gsm->state = GSM_CONTROL; 1856 break; 1857 case GSM_CONTROL: /* Control Byte */ 1858 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1859 gsm->control = c; 1860 gsm->state = GSM_LEN0; 1861 break; 1862 case GSM_LEN0: /* Length EA */ 1863 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1864 if (gsm_read_ea(&gsm->len, c)) { 1865 if (gsm->len > gsm->mru) { 1866 gsm->bad_size++; 1867 gsm->state = GSM_SEARCH; 1868 break; 1869 } 1870 gsm->count = 0; 1871 if (!gsm->len) 1872 gsm->state = GSM_FCS; 1873 else 1874 gsm->state = GSM_DATA; 1875 break; 1876 } 1877 gsm->state = GSM_LEN1; 1878 break; 1879 case GSM_LEN1: 1880 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1881 len = c; 1882 gsm->len |= len << 7; 1883 if (gsm->len > gsm->mru) { 1884 gsm->bad_size++; 1885 gsm->state = GSM_SEARCH; 1886 break; 1887 } 1888 gsm->count = 0; 1889 if (!gsm->len) 1890 gsm->state = GSM_FCS; 1891 else 1892 gsm->state = GSM_DATA; 1893 break; 1894 case GSM_DATA: /* Data */ 1895 gsm->buf[gsm->count++] = c; 1896 if (gsm->count == gsm->len) 1897 gsm->state = GSM_FCS; 1898 break; 1899 case GSM_FCS: /* FCS follows the packet */ 1900 gsm->received_fcs = c; 1901 gsm_queue(gsm); 1902 gsm->state = GSM_SSOF; 1903 break; 1904 case GSM_SSOF: 1905 if (c == GSM0_SOF) { 1906 gsm->state = GSM_SEARCH; 1907 break; 1908 } 1909 break; 1910 } 1911 } 1912 1913 /** 1914 * gsm1_receive - perform processing for non-transparency 1915 * @gsm: gsm data for this ldisc instance 1916 * @c: character 1917 * 1918 * Receive bytes in mode 1 (Advanced option) 1919 */ 1920 1921 static void gsm1_receive(struct gsm_mux *gsm, unsigned char c) 1922 { 1923 if (c == GSM1_SOF) { 1924 /* EOF is only valid in frame if we have got to the data state 1925 and received at least one byte (the FCS) */ 1926 if (gsm->state == GSM_DATA && gsm->count) { 1927 /* Extract the FCS */ 1928 gsm->count--; 1929 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]); 1930 gsm->len = gsm->count; 1931 gsm_queue(gsm); 1932 gsm->state = GSM_START; 1933 return; 1934 } 1935 /* Any partial frame was a runt so go back to start */ 1936 if (gsm->state != GSM_START) { 1937 gsm->malformed++; 1938 gsm->state = GSM_START; 1939 } 1940 /* A SOF in GSM_START means we are still reading idling or 1941 framing bytes */ 1942 return; 1943 } 1944 1945 if (c == GSM1_ESCAPE) { 1946 gsm->escape = 1; 1947 return; 1948 } 1949 1950 /* Only an unescaped SOF gets us out of GSM search */ 1951 if (gsm->state == GSM_SEARCH) 1952 return; 1953 1954 if (gsm->escape) { 1955 c ^= GSM1_ESCAPE_BITS; 1956 gsm->escape = 0; 1957 } 1958 switch (gsm->state) { 1959 case GSM_START: /* First byte after SOF */ 1960 gsm->address = 0; 1961 gsm->state = GSM_ADDRESS; 1962 gsm->fcs = INIT_FCS; 1963 /* Drop through */ 1964 case GSM_ADDRESS: /* Address continuation */ 1965 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1966 if (gsm_read_ea(&gsm->address, c)) 1967 gsm->state = GSM_CONTROL; 1968 break; 1969 case GSM_CONTROL: /* Control Byte */ 1970 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 1971 gsm->control = c; 1972 gsm->count = 0; 1973 gsm->state = GSM_DATA; 1974 break; 1975 case GSM_DATA: /* Data */ 1976 if (gsm->count > gsm->mru) { /* Allow one for the FCS */ 1977 gsm->state = GSM_OVERRUN; 1978 gsm->bad_size++; 1979 } else 1980 gsm->buf[gsm->count++] = c; 1981 break; 1982 case GSM_OVERRUN: /* Over-long - eg a dropped SOF */ 1983 break; 1984 } 1985 } 1986 1987 /** 1988 * gsm_error - handle tty error 1989 * @gsm: ldisc data 1990 * @data: byte received (may be invalid) 1991 * @flag: error received 1992 * 1993 * Handle an error in the receipt of data for a frame. Currently we just 1994 * go back to hunting for a SOF. 1995 * 1996 * FIXME: better diagnostics ? 1997 */ 1998 1999 static void gsm_error(struct gsm_mux *gsm, 2000 unsigned char data, unsigned char flag) 2001 { 2002 gsm->state = GSM_SEARCH; 2003 gsm->io_error++; 2004 } 2005 2006 /** 2007 * gsm_cleanup_mux - generic GSM protocol cleanup 2008 * @gsm: our mux 2009 * 2010 * Clean up the bits of the mux which are the same for all framing 2011 * protocols. Remove the mux from the mux table, stop all the timers 2012 * and then shut down each device hanging up the channels as we go. 2013 */ 2014 2015 void gsm_cleanup_mux(struct gsm_mux *gsm) 2016 { 2017 int i; 2018 struct gsm_dlci *dlci = gsm->dlci[0]; 2019 struct gsm_msg *txq, *ntxq; 2020 struct gsm_control *gc; 2021 2022 gsm->dead = 1; 2023 2024 spin_lock(&gsm_mux_lock); 2025 for (i = 0; i < MAX_MUX; i++) { 2026 if (gsm_mux[i] == gsm) { 2027 gsm_mux[i] = NULL; 2028 break; 2029 } 2030 } 2031 spin_unlock(&gsm_mux_lock); 2032 WARN_ON(i == MAX_MUX); 2033 2034 /* In theory disconnecting DLCI 0 is sufficient but for some 2035 modems this is apparently not the case. */ 2036 if (dlci) { 2037 gc = gsm_control_send(gsm, CMD_CLD, NULL, 0); 2038 if (gc) 2039 gsm_control_wait(gsm, gc); 2040 } 2041 del_timer_sync(&gsm->t2_timer); 2042 /* Now we are sure T2 has stopped */ 2043 if (dlci) { 2044 dlci->dead = 1; 2045 gsm_dlci_begin_close(dlci); 2046 wait_event_interruptible(gsm->event, 2047 dlci->state == DLCI_CLOSED); 2048 } 2049 /* Free up any link layer users */ 2050 for (i = 0; i < NUM_DLCI; i++) 2051 if (gsm->dlci[i]) 2052 gsm_dlci_release(gsm->dlci[i]); 2053 /* Now wipe the queues */ 2054 list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list) 2055 kfree(txq); 2056 INIT_LIST_HEAD(&gsm->tx_list); 2057 } 2058 EXPORT_SYMBOL_GPL(gsm_cleanup_mux); 2059 2060 /** 2061 * gsm_activate_mux - generic GSM setup 2062 * @gsm: our mux 2063 * 2064 * Set up the bits of the mux which are the same for all framing 2065 * protocols. Add the mux to the mux table so it can be opened and 2066 * finally kick off connecting to DLCI 0 on the modem. 2067 */ 2068 2069 int gsm_activate_mux(struct gsm_mux *gsm) 2070 { 2071 struct gsm_dlci *dlci; 2072 int i = 0; 2073 2074 init_timer(&gsm->t2_timer); 2075 gsm->t2_timer.function = gsm_control_retransmit; 2076 gsm->t2_timer.data = (unsigned long)gsm; 2077 init_waitqueue_head(&gsm->event); 2078 spin_lock_init(&gsm->control_lock); 2079 spin_lock_init(&gsm->tx_lock); 2080 2081 if (gsm->encoding == 0) 2082 gsm->receive = gsm0_receive; 2083 else 2084 gsm->receive = gsm1_receive; 2085 gsm->error = gsm_error; 2086 2087 spin_lock(&gsm_mux_lock); 2088 for (i = 0; i < MAX_MUX; i++) { 2089 if (gsm_mux[i] == NULL) { 2090 gsm->num = i; 2091 gsm_mux[i] = gsm; 2092 break; 2093 } 2094 } 2095 spin_unlock(&gsm_mux_lock); 2096 if (i == MAX_MUX) 2097 return -EBUSY; 2098 2099 dlci = gsm_dlci_alloc(gsm, 0); 2100 if (dlci == NULL) 2101 return -ENOMEM; 2102 gsm->dead = 0; /* Tty opens are now permissible */ 2103 return 0; 2104 } 2105 EXPORT_SYMBOL_GPL(gsm_activate_mux); 2106 2107 /** 2108 * gsm_free_mux - free up a mux 2109 * @mux: mux to free 2110 * 2111 * Dispose of allocated resources for a dead mux 2112 */ 2113 void gsm_free_mux(struct gsm_mux *gsm) 2114 { 2115 kfree(gsm->txframe); 2116 kfree(gsm->buf); 2117 kfree(gsm); 2118 } 2119 EXPORT_SYMBOL_GPL(gsm_free_mux); 2120 2121 /** 2122 * gsm_free_muxr - free up a mux 2123 * @mux: mux to free 2124 * 2125 * Dispose of allocated resources for a dead mux 2126 */ 2127 static void gsm_free_muxr(struct kref *ref) 2128 { 2129 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref); 2130 gsm_free_mux(gsm); 2131 } 2132 2133 static inline void mux_get(struct gsm_mux *gsm) 2134 { 2135 kref_get(&gsm->ref); 2136 } 2137 2138 static inline void mux_put(struct gsm_mux *gsm) 2139 { 2140 kref_put(&gsm->ref, gsm_free_muxr); 2141 } 2142 2143 /** 2144 * gsm_alloc_mux - allocate a mux 2145 * 2146 * Creates a new mux ready for activation. 2147 */ 2148 2149 struct gsm_mux *gsm_alloc_mux(void) 2150 { 2151 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL); 2152 if (gsm == NULL) 2153 return NULL; 2154 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL); 2155 if (gsm->buf == NULL) { 2156 kfree(gsm); 2157 return NULL; 2158 } 2159 gsm->txframe = kmalloc(2 * MAX_MRU + 2, GFP_KERNEL); 2160 if (gsm->txframe == NULL) { 2161 kfree(gsm->buf); 2162 kfree(gsm); 2163 return NULL; 2164 } 2165 spin_lock_init(&gsm->lock); 2166 kref_init(&gsm->ref); 2167 INIT_LIST_HEAD(&gsm->tx_list); 2168 2169 gsm->t1 = T1; 2170 gsm->t2 = T2; 2171 gsm->n2 = N2; 2172 gsm->ftype = UIH; 2173 gsm->adaption = 1; 2174 gsm->encoding = 1; 2175 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */ 2176 gsm->mtu = 64; 2177 gsm->dead = 1; /* Avoid early tty opens */ 2178 2179 return gsm; 2180 } 2181 EXPORT_SYMBOL_GPL(gsm_alloc_mux); 2182 2183 /** 2184 * gsmld_output - write to link 2185 * @gsm: our mux 2186 * @data: bytes to output 2187 * @len: size 2188 * 2189 * Write a block of data from the GSM mux to the data channel. This 2190 * will eventually be serialized from above but at the moment isn't. 2191 */ 2192 2193 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len) 2194 { 2195 if (tty_write_room(gsm->tty) < len) { 2196 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags); 2197 return -ENOSPC; 2198 } 2199 if (debug & 4) 2200 print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET, 2201 data, len); 2202 gsm->tty->ops->write(gsm->tty, data, len); 2203 return len; 2204 } 2205 2206 /** 2207 * gsmld_attach_gsm - mode set up 2208 * @tty: our tty structure 2209 * @gsm: our mux 2210 * 2211 * Set up the MUX for basic mode and commence connecting to the 2212 * modem. Currently called from the line discipline set up but 2213 * will need moving to an ioctl path. 2214 */ 2215 2216 static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 2217 { 2218 int ret, i; 2219 int base = gsm->num << 6; /* Base for this MUX */ 2220 2221 gsm->tty = tty_kref_get(tty); 2222 gsm->output = gsmld_output; 2223 ret = gsm_activate_mux(gsm); 2224 if (ret != 0) 2225 tty_kref_put(gsm->tty); 2226 else { 2227 /* Don't register device 0 - this is the control channel and not 2228 a usable tty interface */ 2229 for (i = 1; i < NUM_DLCI; i++) 2230 tty_register_device(gsm_tty_driver, base + i, NULL); 2231 } 2232 return ret; 2233 } 2234 2235 2236 /** 2237 * gsmld_detach_gsm - stop doing 0710 mux 2238 * @tty: tty attached to the mux 2239 * @gsm: mux 2240 * 2241 * Shutdown and then clean up the resources used by the line discipline 2242 */ 2243 2244 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 2245 { 2246 int i; 2247 int base = gsm->num << 6; /* Base for this MUX */ 2248 2249 WARN_ON(tty != gsm->tty); 2250 for (i = 1; i < NUM_DLCI; i++) 2251 tty_unregister_device(gsm_tty_driver, base + i); 2252 gsm_cleanup_mux(gsm); 2253 tty_kref_put(gsm->tty); 2254 gsm->tty = NULL; 2255 } 2256 2257 static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, 2258 char *fp, int count) 2259 { 2260 struct gsm_mux *gsm = tty->disc_data; 2261 const unsigned char *dp; 2262 char *f; 2263 int i; 2264 char buf[64]; 2265 char flags; 2266 2267 if (debug & 4) 2268 print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET, 2269 cp, count); 2270 2271 for (i = count, dp = cp, f = fp; i; i--, dp++) { 2272 flags = *f++; 2273 switch (flags) { 2274 case TTY_NORMAL: 2275 gsm->receive(gsm, *dp); 2276 break; 2277 case TTY_OVERRUN: 2278 case TTY_BREAK: 2279 case TTY_PARITY: 2280 case TTY_FRAME: 2281 gsm->error(gsm, *dp, flags); 2282 break; 2283 default: 2284 WARN_ONCE(1, "%s: unknown flag %d\n", 2285 tty_name(tty, buf), flags); 2286 break; 2287 } 2288 } 2289 /* FASYNC if needed ? */ 2290 /* If clogged call tty_throttle(tty); */ 2291 } 2292 2293 /** 2294 * gsmld_chars_in_buffer - report available bytes 2295 * @tty: tty device 2296 * 2297 * Report the number of characters buffered to be delivered to user 2298 * at this instant in time. 2299 * 2300 * Locking: gsm lock 2301 */ 2302 2303 static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty) 2304 { 2305 return 0; 2306 } 2307 2308 /** 2309 * gsmld_flush_buffer - clean input queue 2310 * @tty: terminal device 2311 * 2312 * Flush the input buffer. Called when the line discipline is 2313 * being closed, when the tty layer wants the buffer flushed (eg 2314 * at hangup). 2315 */ 2316 2317 static void gsmld_flush_buffer(struct tty_struct *tty) 2318 { 2319 } 2320 2321 /** 2322 * gsmld_close - close the ldisc for this tty 2323 * @tty: device 2324 * 2325 * Called from the terminal layer when this line discipline is 2326 * being shut down, either because of a close or becsuse of a 2327 * discipline change. The function will not be called while other 2328 * ldisc methods are in progress. 2329 */ 2330 2331 static void gsmld_close(struct tty_struct *tty) 2332 { 2333 struct gsm_mux *gsm = tty->disc_data; 2334 2335 gsmld_detach_gsm(tty, gsm); 2336 2337 gsmld_flush_buffer(tty); 2338 /* Do other clean up here */ 2339 mux_put(gsm); 2340 } 2341 2342 /** 2343 * gsmld_open - open an ldisc 2344 * @tty: terminal to open 2345 * 2346 * Called when this line discipline is being attached to the 2347 * terminal device. Can sleep. Called serialized so that no 2348 * other events will occur in parallel. No further open will occur 2349 * until a close. 2350 */ 2351 2352 static int gsmld_open(struct tty_struct *tty) 2353 { 2354 struct gsm_mux *gsm; 2355 2356 if (tty->ops->write == NULL) 2357 return -EINVAL; 2358 2359 /* Attach our ldisc data */ 2360 gsm = gsm_alloc_mux(); 2361 if (gsm == NULL) 2362 return -ENOMEM; 2363 2364 tty->disc_data = gsm; 2365 tty->receive_room = 65536; 2366 2367 /* Attach the initial passive connection */ 2368 gsm->encoding = 1; 2369 return gsmld_attach_gsm(tty, gsm); 2370 } 2371 2372 /** 2373 * gsmld_write_wakeup - asynchronous I/O notifier 2374 * @tty: tty device 2375 * 2376 * Required for the ptys, serial driver etc. since processes 2377 * that attach themselves to the master and rely on ASYNC 2378 * IO must be woken up 2379 */ 2380 2381 static void gsmld_write_wakeup(struct tty_struct *tty) 2382 { 2383 struct gsm_mux *gsm = tty->disc_data; 2384 unsigned long flags; 2385 2386 /* Queue poll */ 2387 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 2388 spin_lock_irqsave(&gsm->tx_lock, flags); 2389 gsm_data_kick(gsm); 2390 if (gsm->tx_bytes < TX_THRESH_LO) { 2391 gsm_dlci_data_sweep(gsm); 2392 } 2393 spin_unlock_irqrestore(&gsm->tx_lock, flags); 2394 } 2395 2396 /** 2397 * gsmld_read - read function for tty 2398 * @tty: tty device 2399 * @file: file object 2400 * @buf: userspace buffer pointer 2401 * @nr: size of I/O 2402 * 2403 * Perform reads for the line discipline. We are guaranteed that the 2404 * line discipline will not be closed under us but we may get multiple 2405 * parallel readers and must handle this ourselves. We may also get 2406 * a hangup. Always called in user context, may sleep. 2407 * 2408 * This code must be sure never to sleep through a hangup. 2409 */ 2410 2411 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, 2412 unsigned char __user *buf, size_t nr) 2413 { 2414 return -EOPNOTSUPP; 2415 } 2416 2417 /** 2418 * gsmld_write - write function for tty 2419 * @tty: tty device 2420 * @file: file object 2421 * @buf: userspace buffer pointer 2422 * @nr: size of I/O 2423 * 2424 * Called when the owner of the device wants to send a frame 2425 * itself (or some other control data). The data is transferred 2426 * as-is and must be properly framed and checksummed as appropriate 2427 * by userspace. Frames are either sent whole or not at all as this 2428 * avoids pain user side. 2429 */ 2430 2431 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file, 2432 const unsigned char *buf, size_t nr) 2433 { 2434 int space = tty_write_room(tty); 2435 if (space >= nr) 2436 return tty->ops->write(tty, buf, nr); 2437 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 2438 return -ENOBUFS; 2439 } 2440 2441 /** 2442 * gsmld_poll - poll method for N_GSM0710 2443 * @tty: terminal device 2444 * @file: file accessing it 2445 * @wait: poll table 2446 * 2447 * Called when the line discipline is asked to poll() for data or 2448 * for special events. This code is not serialized with respect to 2449 * other events save open/close. 2450 * 2451 * This code must be sure never to sleep through a hangup. 2452 * Called without the kernel lock held - fine 2453 */ 2454 2455 static unsigned int gsmld_poll(struct tty_struct *tty, struct file *file, 2456 poll_table *wait) 2457 { 2458 unsigned int mask = 0; 2459 struct gsm_mux *gsm = tty->disc_data; 2460 2461 poll_wait(file, &tty->read_wait, wait); 2462 poll_wait(file, &tty->write_wait, wait); 2463 if (tty_hung_up_p(file)) 2464 mask |= POLLHUP; 2465 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0) 2466 mask |= POLLOUT | POLLWRNORM; 2467 if (gsm->dead) 2468 mask |= POLLHUP; 2469 return mask; 2470 } 2471 2472 static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm, 2473 struct gsm_config *c) 2474 { 2475 int need_close = 0; 2476 int need_restart = 0; 2477 2478 /* Stuff we don't support yet - UI or I frame transport, windowing */ 2479 if ((c->adaption != 1 && c->adaption != 2) || c->k) 2480 return -EOPNOTSUPP; 2481 /* Check the MRU/MTU range looks sane */ 2482 if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8) 2483 return -EINVAL; 2484 if (c->n2 < 3) 2485 return -EINVAL; 2486 if (c->encapsulation > 1) /* Basic, advanced, no I */ 2487 return -EINVAL; 2488 if (c->initiator > 1) 2489 return -EINVAL; 2490 if (c->i == 0 || c->i > 2) /* UIH and UI only */ 2491 return -EINVAL; 2492 /* 2493 * See what is needed for reconfiguration 2494 */ 2495 2496 /* Timing fields */ 2497 if (c->t1 != 0 && c->t1 != gsm->t1) 2498 need_restart = 1; 2499 if (c->t2 != 0 && c->t2 != gsm->t2) 2500 need_restart = 1; 2501 if (c->encapsulation != gsm->encoding) 2502 need_restart = 1; 2503 if (c->adaption != gsm->adaption) 2504 need_restart = 1; 2505 /* Requires care */ 2506 if (c->initiator != gsm->initiator) 2507 need_close = 1; 2508 if (c->mru != gsm->mru) 2509 need_restart = 1; 2510 if (c->mtu != gsm->mtu) 2511 need_restart = 1; 2512 2513 /* 2514 * Close down what is needed, restart and initiate the new 2515 * configuration 2516 */ 2517 2518 if (need_close || need_restart) { 2519 gsm_dlci_begin_close(gsm->dlci[0]); 2520 /* This will timeout if the link is down due to N2 expiring */ 2521 wait_event_interruptible(gsm->event, 2522 gsm->dlci[0]->state == DLCI_CLOSED); 2523 if (signal_pending(current)) 2524 return -EINTR; 2525 } 2526 if (need_restart) 2527 gsm_cleanup_mux(gsm); 2528 2529 gsm->initiator = c->initiator; 2530 gsm->mru = c->mru; 2531 gsm->mtu = c->mtu; 2532 gsm->encoding = c->encapsulation; 2533 gsm->adaption = c->adaption; 2534 gsm->n2 = c->n2; 2535 2536 if (c->i == 1) 2537 gsm->ftype = UIH; 2538 else if (c->i == 2) 2539 gsm->ftype = UI; 2540 2541 if (c->t1) 2542 gsm->t1 = c->t1; 2543 if (c->t2) 2544 gsm->t2 = c->t2; 2545 2546 /* FIXME: We need to separate activation/deactivation from adding 2547 and removing from the mux array */ 2548 if (need_restart) 2549 gsm_activate_mux(gsm); 2550 if (gsm->initiator && need_close) 2551 gsm_dlci_begin_open(gsm->dlci[0]); 2552 return 0; 2553 } 2554 2555 static int gsmld_ioctl(struct tty_struct *tty, struct file *file, 2556 unsigned int cmd, unsigned long arg) 2557 { 2558 struct gsm_config c; 2559 struct gsm_mux *gsm = tty->disc_data; 2560 2561 switch (cmd) { 2562 case GSMIOC_GETCONF: 2563 memset(&c, 0, sizeof(c)); 2564 c.adaption = gsm->adaption; 2565 c.encapsulation = gsm->encoding; 2566 c.initiator = gsm->initiator; 2567 c.t1 = gsm->t1; 2568 c.t2 = gsm->t2; 2569 c.t3 = 0; /* Not supported */ 2570 c.n2 = gsm->n2; 2571 if (gsm->ftype == UIH) 2572 c.i = 1; 2573 else 2574 c.i = 2; 2575 pr_debug("Ftype %d i %d\n", gsm->ftype, c.i); 2576 c.mru = gsm->mru; 2577 c.mtu = gsm->mtu; 2578 c.k = 0; 2579 if (copy_to_user((void *)arg, &c, sizeof(c))) 2580 return -EFAULT; 2581 return 0; 2582 case GSMIOC_SETCONF: 2583 if (copy_from_user(&c, (void *)arg, sizeof(c))) 2584 return -EFAULT; 2585 return gsmld_config(tty, gsm, &c); 2586 default: 2587 return n_tty_ioctl_helper(tty, file, cmd, arg); 2588 } 2589 } 2590 2591 /* 2592 * Network interface 2593 * 2594 */ 2595 2596 static int gsm_mux_net_open(struct net_device *net) 2597 { 2598 pr_debug("%s called\n", __func__); 2599 netif_start_queue(net); 2600 return 0; 2601 } 2602 2603 static int gsm_mux_net_close(struct net_device *net) 2604 { 2605 netif_stop_queue(net); 2606 return 0; 2607 } 2608 2609 static struct net_device_stats *gsm_mux_net_get_stats(struct net_device *net) 2610 { 2611 return &((struct gsm_mux_net *)netdev_priv(net))->stats; 2612 } 2613 static void dlci_net_free(struct gsm_dlci *dlci) 2614 { 2615 if (!dlci->net) { 2616 WARN_ON(1); 2617 return; 2618 } 2619 dlci->adaption = dlci->prev_adaption; 2620 dlci->data = dlci->prev_data; 2621 free_netdev(dlci->net); 2622 dlci->net = NULL; 2623 } 2624 static void net_free(struct kref *ref) 2625 { 2626 struct gsm_mux_net *mux_net; 2627 struct gsm_dlci *dlci; 2628 2629 mux_net = container_of(ref, struct gsm_mux_net, ref); 2630 dlci = mux_net->dlci; 2631 2632 if (dlci->net) { 2633 unregister_netdev(dlci->net); 2634 dlci_net_free(dlci); 2635 } 2636 } 2637 2638 static inline void muxnet_get(struct gsm_mux_net *mux_net) 2639 { 2640 kref_get(&mux_net->ref); 2641 } 2642 2643 static inline void muxnet_put(struct gsm_mux_net *mux_net) 2644 { 2645 kref_put(&mux_net->ref, net_free); 2646 } 2647 2648 static int gsm_mux_net_start_xmit(struct sk_buff *skb, 2649 struct net_device *net) 2650 { 2651 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net); 2652 struct gsm_dlci *dlci = mux_net->dlci; 2653 muxnet_get(mux_net); 2654 2655 skb_queue_head(&dlci->skb_list, skb); 2656 STATS(net).tx_packets++; 2657 STATS(net).tx_bytes += skb->len; 2658 gsm_dlci_data_kick(dlci); 2659 /* And tell the kernel when the last transmit started. */ 2660 net->trans_start = jiffies; 2661 muxnet_put(mux_net); 2662 return NETDEV_TX_OK; 2663 } 2664 2665 /* called when a packet did not ack after watchdogtimeout */ 2666 static void gsm_mux_net_tx_timeout(struct net_device *net) 2667 { 2668 /* Tell syslog we are hosed. */ 2669 dev_dbg(&net->dev, "Tx timed out.\n"); 2670 2671 /* Update statistics */ 2672 STATS(net).tx_errors++; 2673 } 2674 2675 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci, 2676 unsigned char *in_buf, int size) 2677 { 2678 struct net_device *net = dlci->net; 2679 struct sk_buff *skb; 2680 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net); 2681 muxnet_get(mux_net); 2682 2683 /* Allocate an sk_buff */ 2684 skb = dev_alloc_skb(size + NET_IP_ALIGN); 2685 if (!skb) { 2686 /* We got no receive buffer. */ 2687 STATS(net).rx_dropped++; 2688 muxnet_put(mux_net); 2689 return; 2690 } 2691 skb_reserve(skb, NET_IP_ALIGN); 2692 memcpy(skb_put(skb, size), in_buf, size); 2693 2694 skb->dev = net; 2695 skb->protocol = __constant_htons(ETH_P_IP); 2696 2697 /* Ship it off to the kernel */ 2698 netif_rx(skb); 2699 2700 /* update out statistics */ 2701 STATS(net).rx_packets++; 2702 STATS(net).rx_bytes += size; 2703 muxnet_put(mux_net); 2704 return; 2705 } 2706 2707 int gsm_change_mtu(struct net_device *net, int new_mtu) 2708 { 2709 struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net); 2710 if ((new_mtu < 8) || (new_mtu > mux_net->dlci->gsm->mtu)) 2711 return -EINVAL; 2712 net->mtu = new_mtu; 2713 return 0; 2714 } 2715 2716 static void gsm_mux_net_init(struct net_device *net) 2717 { 2718 static const struct net_device_ops gsm_netdev_ops = { 2719 .ndo_open = gsm_mux_net_open, 2720 .ndo_stop = gsm_mux_net_close, 2721 .ndo_start_xmit = gsm_mux_net_start_xmit, 2722 .ndo_tx_timeout = gsm_mux_net_tx_timeout, 2723 .ndo_get_stats = gsm_mux_net_get_stats, 2724 .ndo_change_mtu = gsm_change_mtu, 2725 }; 2726 2727 net->netdev_ops = &gsm_netdev_ops; 2728 2729 /* fill in the other fields */ 2730 net->watchdog_timeo = GSM_NET_TX_TIMEOUT; 2731 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 2732 net->type = ARPHRD_NONE; 2733 net->tx_queue_len = 10; 2734 } 2735 2736 2737 /* caller holds the dlci mutex */ 2738 static void gsm_destroy_network(struct gsm_dlci *dlci) 2739 { 2740 struct gsm_mux_net *mux_net; 2741 2742 pr_debug("destroy network interface"); 2743 if (!dlci->net) 2744 return; 2745 mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net); 2746 muxnet_put(mux_net); 2747 } 2748 2749 2750 /* caller holds the dlci mutex */ 2751 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc) 2752 { 2753 char *netname; 2754 int retval = 0; 2755 struct net_device *net; 2756 struct gsm_mux_net *mux_net; 2757 2758 if (!capable(CAP_NET_ADMIN)) 2759 return -EPERM; 2760 2761 /* Already in a non tty mode */ 2762 if (dlci->adaption > 2) 2763 return -EBUSY; 2764 2765 if (nc->protocol != htons(ETH_P_IP)) 2766 return -EPROTONOSUPPORT; 2767 2768 if (nc->adaption != 3 && nc->adaption != 4) 2769 return -EPROTONOSUPPORT; 2770 2771 pr_debug("create network interface"); 2772 2773 netname = "gsm%d"; 2774 if (nc->if_name[0] != '\0') 2775 netname = nc->if_name; 2776 net = alloc_netdev(sizeof(struct gsm_mux_net), 2777 netname, 2778 gsm_mux_net_init); 2779 if (!net) { 2780 pr_err("alloc_netdev failed"); 2781 return -ENOMEM; 2782 } 2783 net->mtu = dlci->gsm->mtu; 2784 mux_net = (struct gsm_mux_net *)netdev_priv(net); 2785 mux_net->dlci = dlci; 2786 kref_init(&mux_net->ref); 2787 strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */ 2788 2789 /* reconfigure dlci for network */ 2790 dlci->prev_adaption = dlci->adaption; 2791 dlci->prev_data = dlci->data; 2792 dlci->adaption = nc->adaption; 2793 dlci->data = gsm_mux_rx_netchar; 2794 dlci->net = net; 2795 2796 pr_debug("register netdev"); 2797 retval = register_netdev(net); 2798 if (retval) { 2799 pr_err("network register fail %d\n", retval); 2800 dlci_net_free(dlci); 2801 return retval; 2802 } 2803 return net->ifindex; /* return network index */ 2804 } 2805 2806 /* Line discipline for real tty */ 2807 struct tty_ldisc_ops tty_ldisc_packet = { 2808 .owner = THIS_MODULE, 2809 .magic = TTY_LDISC_MAGIC, 2810 .name = "n_gsm", 2811 .open = gsmld_open, 2812 .close = gsmld_close, 2813 .flush_buffer = gsmld_flush_buffer, 2814 .chars_in_buffer = gsmld_chars_in_buffer, 2815 .read = gsmld_read, 2816 .write = gsmld_write, 2817 .ioctl = gsmld_ioctl, 2818 .poll = gsmld_poll, 2819 .receive_buf = gsmld_receive_buf, 2820 .write_wakeup = gsmld_write_wakeup 2821 }; 2822 2823 /* 2824 * Virtual tty side 2825 */ 2826 2827 #define TX_SIZE 512 2828 2829 static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) 2830 { 2831 u8 modembits[5]; 2832 struct gsm_control *ctrl; 2833 int len = 2; 2834 2835 if (brk) 2836 len++; 2837 2838 modembits[0] = len << 1 | EA; /* Data bytes */ 2839 modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */ 2840 modembits[2] = gsm_encode_modem(dlci) << 1 | EA; 2841 if (brk) 2842 modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */ 2843 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1); 2844 if (ctrl == NULL) 2845 return -ENOMEM; 2846 return gsm_control_wait(dlci->gsm, ctrl); 2847 } 2848 2849 static int gsm_carrier_raised(struct tty_port *port) 2850 { 2851 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2852 /* Not yet open so no carrier info */ 2853 if (dlci->state != DLCI_OPEN) 2854 return 0; 2855 if (debug & 2) 2856 return 1; 2857 return dlci->modem_rx & TIOCM_CD; 2858 } 2859 2860 static void gsm_dtr_rts(struct tty_port *port, int onoff) 2861 { 2862 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2863 unsigned int modem_tx = dlci->modem_tx; 2864 if (onoff) 2865 modem_tx |= TIOCM_DTR | TIOCM_RTS; 2866 else 2867 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); 2868 if (modem_tx != dlci->modem_tx) { 2869 dlci->modem_tx = modem_tx; 2870 gsmtty_modem_update(dlci, 0); 2871 } 2872 } 2873 2874 static const struct tty_port_operations gsm_port_ops = { 2875 .carrier_raised = gsm_carrier_raised, 2876 .dtr_rts = gsm_dtr_rts, 2877 }; 2878 2879 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty) 2880 { 2881 struct gsm_mux *gsm; 2882 struct gsm_dlci *dlci; 2883 unsigned int line = tty->index; 2884 unsigned int mux = line >> 6; 2885 bool alloc = false; 2886 int ret; 2887 2888 line = line & 0x3F; 2889 2890 if (mux >= MAX_MUX) 2891 return -ENXIO; 2892 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */ 2893 if (gsm_mux[mux] == NULL) 2894 return -EUNATCH; 2895 if (line == 0 || line > 61) /* 62/63 reserved */ 2896 return -ECHRNG; 2897 gsm = gsm_mux[mux]; 2898 if (gsm->dead) 2899 return -EL2HLT; 2900 /* If DLCI 0 is not yet fully open return an error. This is ok from a locking 2901 perspective as we don't have to worry about this if DLCI0 is lost */ 2902 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) 2903 return -EL2NSYNC; 2904 dlci = gsm->dlci[line]; 2905 if (dlci == NULL) { 2906 alloc = true; 2907 dlci = gsm_dlci_alloc(gsm, line); 2908 } 2909 if (dlci == NULL) 2910 return -ENOMEM; 2911 ret = tty_port_install(&dlci->port, driver, tty); 2912 if (ret) { 2913 if (alloc) 2914 dlci_put(dlci); 2915 return ret; 2916 } 2917 2918 tty->driver_data = dlci; 2919 2920 return 0; 2921 } 2922 2923 static int gsmtty_open(struct tty_struct *tty, struct file *filp) 2924 { 2925 struct gsm_dlci *dlci = tty->driver_data; 2926 struct tty_port *port = &dlci->port; 2927 2928 port->count++; 2929 dlci_get(dlci); 2930 dlci_get(dlci->gsm->dlci[0]); 2931 mux_get(dlci->gsm); 2932 tty_port_tty_set(port, tty); 2933 2934 dlci->modem_rx = 0; 2935 /* We could in theory open and close before we wait - eg if we get 2936 a DM straight back. This is ok as that will have caused a hangup */ 2937 set_bit(ASYNCB_INITIALIZED, &port->flags); 2938 /* Start sending off SABM messages */ 2939 gsm_dlci_begin_open(dlci); 2940 /* And wait for virtual carrier */ 2941 return tty_port_block_til_ready(port, tty, filp); 2942 } 2943 2944 static void gsmtty_close(struct tty_struct *tty, struct file *filp) 2945 { 2946 struct gsm_dlci *dlci = tty->driver_data; 2947 struct gsm_mux *gsm; 2948 2949 if (dlci == NULL) 2950 return; 2951 mutex_lock(&dlci->mutex); 2952 gsm_destroy_network(dlci); 2953 mutex_unlock(&dlci->mutex); 2954 gsm = dlci->gsm; 2955 if (tty_port_close_start(&dlci->port, tty, filp) == 0) 2956 goto out; 2957 gsm_dlci_begin_close(dlci); 2958 tty_port_close_end(&dlci->port, tty); 2959 tty_port_tty_set(&dlci->port, NULL); 2960 out: 2961 dlci_put(dlci); 2962 dlci_put(gsm->dlci[0]); 2963 mux_put(gsm); 2964 } 2965 2966 static void gsmtty_hangup(struct tty_struct *tty) 2967 { 2968 struct gsm_dlci *dlci = tty->driver_data; 2969 tty_port_hangup(&dlci->port); 2970 gsm_dlci_begin_close(dlci); 2971 } 2972 2973 static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf, 2974 int len) 2975 { 2976 struct gsm_dlci *dlci = tty->driver_data; 2977 /* Stuff the bytes into the fifo queue */ 2978 int sent = kfifo_in_locked(dlci->fifo, buf, len, &dlci->lock); 2979 /* Need to kick the channel */ 2980 gsm_dlci_data_kick(dlci); 2981 return sent; 2982 } 2983 2984 static int gsmtty_write_room(struct tty_struct *tty) 2985 { 2986 struct gsm_dlci *dlci = tty->driver_data; 2987 return TX_SIZE - kfifo_len(dlci->fifo); 2988 } 2989 2990 static int gsmtty_chars_in_buffer(struct tty_struct *tty) 2991 { 2992 struct gsm_dlci *dlci = tty->driver_data; 2993 return kfifo_len(dlci->fifo); 2994 } 2995 2996 static void gsmtty_flush_buffer(struct tty_struct *tty) 2997 { 2998 struct gsm_dlci *dlci = tty->driver_data; 2999 /* Caution needed: If we implement reliable transport classes 3000 then the data being transmitted can't simply be junked once 3001 it has first hit the stack. Until then we can just blow it 3002 away */ 3003 kfifo_reset(dlci->fifo); 3004 /* Need to unhook this DLCI from the transmit queue logic */ 3005 } 3006 3007 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout) 3008 { 3009 /* The FIFO handles the queue so the kernel will do the right 3010 thing waiting on chars_in_buffer before calling us. No work 3011 to do here */ 3012 } 3013 3014 static int gsmtty_tiocmget(struct tty_struct *tty) 3015 { 3016 struct gsm_dlci *dlci = tty->driver_data; 3017 return dlci->modem_rx; 3018 } 3019 3020 static int gsmtty_tiocmset(struct tty_struct *tty, 3021 unsigned int set, unsigned int clear) 3022 { 3023 struct gsm_dlci *dlci = tty->driver_data; 3024 unsigned int modem_tx = dlci->modem_tx; 3025 3026 modem_tx &= ~clear; 3027 modem_tx |= set; 3028 3029 if (modem_tx != dlci->modem_tx) { 3030 dlci->modem_tx = modem_tx; 3031 return gsmtty_modem_update(dlci, 0); 3032 } 3033 return 0; 3034 } 3035 3036 3037 static int gsmtty_ioctl(struct tty_struct *tty, 3038 unsigned int cmd, unsigned long arg) 3039 { 3040 struct gsm_dlci *dlci = tty->driver_data; 3041 struct gsm_netconfig nc; 3042 int index; 3043 3044 switch (cmd) { 3045 case GSMIOC_ENABLE_NET: 3046 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc))) 3047 return -EFAULT; 3048 nc.if_name[IFNAMSIZ-1] = '\0'; 3049 /* return net interface index or error code */ 3050 mutex_lock(&dlci->mutex); 3051 index = gsm_create_network(dlci, &nc); 3052 mutex_unlock(&dlci->mutex); 3053 if (copy_to_user((void __user *)arg, &nc, sizeof(nc))) 3054 return -EFAULT; 3055 return index; 3056 case GSMIOC_DISABLE_NET: 3057 if (!capable(CAP_NET_ADMIN)) 3058 return -EPERM; 3059 mutex_lock(&dlci->mutex); 3060 gsm_destroy_network(dlci); 3061 mutex_unlock(&dlci->mutex); 3062 return 0; 3063 default: 3064 return -ENOIOCTLCMD; 3065 } 3066 } 3067 3068 static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old) 3069 { 3070 /* For the moment its fixed. In actual fact the speed information 3071 for the virtual channel can be propogated in both directions by 3072 the RPN control message. This however rapidly gets nasty as we 3073 then have to remap modem signals each way according to whether 3074 our virtual cable is null modem etc .. */ 3075 tty_termios_copy_hw(&tty->termios, old); 3076 } 3077 3078 static void gsmtty_throttle(struct tty_struct *tty) 3079 { 3080 struct gsm_dlci *dlci = tty->driver_data; 3081 if (tty->termios.c_cflag & CRTSCTS) 3082 dlci->modem_tx &= ~TIOCM_DTR; 3083 dlci->throttled = 1; 3084 /* Send an MSC with DTR cleared */ 3085 gsmtty_modem_update(dlci, 0); 3086 } 3087 3088 static void gsmtty_unthrottle(struct tty_struct *tty) 3089 { 3090 struct gsm_dlci *dlci = tty->driver_data; 3091 if (tty->termios.c_cflag & CRTSCTS) 3092 dlci->modem_tx |= TIOCM_DTR; 3093 dlci->throttled = 0; 3094 /* Send an MSC with DTR set */ 3095 gsmtty_modem_update(dlci, 0); 3096 } 3097 3098 static int gsmtty_break_ctl(struct tty_struct *tty, int state) 3099 { 3100 struct gsm_dlci *dlci = tty->driver_data; 3101 int encode = 0; /* Off */ 3102 3103 if (state == -1) /* "On indefinitely" - we can't encode this 3104 properly */ 3105 encode = 0x0F; 3106 else if (state > 0) { 3107 encode = state / 200; /* mS to encoding */ 3108 if (encode > 0x0F) 3109 encode = 0x0F; /* Best effort */ 3110 } 3111 return gsmtty_modem_update(dlci, encode); 3112 } 3113 3114 3115 /* Virtual ttys for the demux */ 3116 static const struct tty_operations gsmtty_ops = { 3117 .install = gsmtty_install, 3118 .open = gsmtty_open, 3119 .close = gsmtty_close, 3120 .write = gsmtty_write, 3121 .write_room = gsmtty_write_room, 3122 .chars_in_buffer = gsmtty_chars_in_buffer, 3123 .flush_buffer = gsmtty_flush_buffer, 3124 .ioctl = gsmtty_ioctl, 3125 .throttle = gsmtty_throttle, 3126 .unthrottle = gsmtty_unthrottle, 3127 .set_termios = gsmtty_set_termios, 3128 .hangup = gsmtty_hangup, 3129 .wait_until_sent = gsmtty_wait_until_sent, 3130 .tiocmget = gsmtty_tiocmget, 3131 .tiocmset = gsmtty_tiocmset, 3132 .break_ctl = gsmtty_break_ctl, 3133 }; 3134 3135 3136 3137 static int __init gsm_init(void) 3138 { 3139 /* Fill in our line protocol discipline, and register it */ 3140 int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet); 3141 if (status != 0) { 3142 pr_err("n_gsm: can't register line discipline (err = %d)\n", 3143 status); 3144 return status; 3145 } 3146 3147 gsm_tty_driver = alloc_tty_driver(256); 3148 if (!gsm_tty_driver) { 3149 tty_unregister_ldisc(N_GSM0710); 3150 pr_err("gsm_init: tty allocation failed.\n"); 3151 return -EINVAL; 3152 } 3153 gsm_tty_driver->driver_name = "gsmtty"; 3154 gsm_tty_driver->name = "gsmtty"; 3155 gsm_tty_driver->major = 0; /* Dynamic */ 3156 gsm_tty_driver->minor_start = 0; 3157 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; 3158 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL; 3159 gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV 3160 | TTY_DRIVER_HARDWARE_BREAK; 3161 gsm_tty_driver->init_termios = tty_std_termios; 3162 /* Fixme */ 3163 gsm_tty_driver->init_termios.c_lflag &= ~ECHO; 3164 tty_set_operations(gsm_tty_driver, &gsmtty_ops); 3165 3166 spin_lock_init(&gsm_mux_lock); 3167 3168 if (tty_register_driver(gsm_tty_driver)) { 3169 put_tty_driver(gsm_tty_driver); 3170 tty_unregister_ldisc(N_GSM0710); 3171 pr_err("gsm_init: tty registration failed.\n"); 3172 return -EBUSY; 3173 } 3174 pr_debug("gsm_init: loaded as %d,%d.\n", 3175 gsm_tty_driver->major, gsm_tty_driver->minor_start); 3176 return 0; 3177 } 3178 3179 static void __exit gsm_exit(void) 3180 { 3181 int status = tty_unregister_ldisc(N_GSM0710); 3182 if (status != 0) 3183 pr_err("n_gsm: can't unregister line discipline (err = %d)\n", 3184 status); 3185 tty_unregister_driver(gsm_tty_driver); 3186 put_tty_driver(gsm_tty_driver); 3187 } 3188 3189 module_init(gsm_init); 3190 module_exit(gsm_exit); 3191 3192 3193 MODULE_LICENSE("GPL"); 3194 MODULE_ALIAS_LDISC(N_GSM0710); 3195