1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * n_gsm.c GSM 0710 tty multiplexor 4 * Copyright (c) 2009/10 Intel Corporation 5 * Copyright (c) 2022/23 Siemens Mobility GmbH 6 * 7 * * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE * 8 * 9 * Outgoing path: 10 * tty -> DLCI fifo -> scheduler -> GSM MUX data queue ---o-> ldisc 11 * control message -> GSM MUX control queue --´ 12 * 13 * Incoming path: 14 * ldisc -> gsm_queue() -o--> tty 15 * `-> gsm_control_response() 16 * 17 * TO DO: 18 * Mostly done: ioctls for setting modes/timing 19 * Partly done: hooks so you can pull off frames to non tty devs 20 * Restart DLCI 0 when it closes ? 21 * Improve the tx engine 22 * Resolve tx side locking by adding a queue_head and routing 23 * all control traffic via it 24 * General tidy/document 25 * Review the locking/move to refcounts more (mux now moved to an 26 * alloc/free model ready) 27 * Use newest tty open/close port helpers and install hooks 28 * What to do about power functions ? 29 * Termios setting and negotiation 30 * Do we need a 'which mux are you' ioctl to correlate mux and tty sets 31 * 32 */ 33 34 #include <linux/types.h> 35 #include <linux/major.h> 36 #include <linux/errno.h> 37 #include <linux/signal.h> 38 #include <linux/fcntl.h> 39 #include <linux/sched/signal.h> 40 #include <linux/interrupt.h> 41 #include <linux/tty.h> 42 #include <linux/bitfield.h> 43 #include <linux/ctype.h> 44 #include <linux/mm.h> 45 #include <linux/math.h> 46 #include <linux/nospec.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 #include "tty.h" 66 67 static int debug; 68 module_param(debug, int, 0600); 69 70 /* Module debug bits */ 71 #define DBG_DUMP BIT(0) /* Data transmission dump. */ 72 #define DBG_CD_ON BIT(1) /* Always assume CD line on. */ 73 #define DBG_DATA BIT(2) /* Data transmission details. */ 74 #define DBG_ERRORS BIT(3) /* Details for fail conditions. */ 75 #define DBG_TTY BIT(4) /* Transmission statistics for DLCI TTYs. */ 76 #define DBG_PAYLOAD BIT(5) /* Limits DBG_DUMP to payload frames. */ 77 78 /* Defaults: these are from the specification */ 79 80 #define T1 10 /* 100mS */ 81 #define T2 34 /* 333mS */ 82 #define T3 10 /* 10s */ 83 #define N2 3 /* Retry 3 times */ 84 #define K 2 /* outstanding I frames */ 85 86 #define MAX_T3 255 /* In seconds. */ 87 #define MAX_WINDOW_SIZE 7 /* Limit of K in error recovery mode. */ 88 89 /* Use long timers for testing at low speed with debug on */ 90 #ifdef DEBUG_TIMING 91 #define T1 100 92 #define T2 200 93 #endif 94 95 /* 96 * Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte 97 * limits so this is plenty 98 */ 99 #define MAX_MRU 1500 100 #define MAX_MTU 1500 101 #define MIN_MTU (PROT_OVERHEAD + 1) 102 /* SOF, ADDR, CTRL, LEN1, LEN2, ..., FCS, EOF */ 103 #define PROT_OVERHEAD 7 104 #define GSM_NET_TX_TIMEOUT (HZ*10) 105 106 /* 107 * struct gsm_mux_net - network interface 108 * 109 * Created when net interface is initialized. 110 */ 111 struct gsm_mux_net { 112 struct kref ref; 113 struct gsm_dlci *dlci; 114 }; 115 116 /* 117 * Each block of data we have queued to go out is in the form of 118 * a gsm_msg which holds everything we need in a link layer independent 119 * format 120 */ 121 122 struct gsm_msg { 123 struct list_head list; 124 u8 addr; /* DLCI address + flags */ 125 u8 ctrl; /* Control byte + flags */ 126 unsigned int len; /* Length of data block (can be zero) */ 127 u8 *data; /* Points into buffer but not at the start */ 128 u8 buffer[]; 129 }; 130 131 enum gsm_dlci_state { 132 DLCI_CLOSED, 133 DLCI_WAITING_CONFIG, /* Waiting for DLCI configuration from user */ 134 DLCI_CONFIGURE, /* Sending PN (for adaption > 1) */ 135 DLCI_OPENING, /* Sending SABM not seen UA */ 136 DLCI_OPEN, /* SABM/UA complete */ 137 DLCI_CLOSING, /* Sending DISC not seen UA/DM */ 138 }; 139 140 enum gsm_dlci_mode { 141 DLCI_MODE_ABM, /* Normal Asynchronous Balanced Mode */ 142 DLCI_MODE_ADM, /* Asynchronous Disconnected Mode */ 143 }; 144 145 /* 146 * Each active data link has a gsm_dlci structure associated which ties 147 * the link layer to an optional tty (if the tty side is open). To avoid 148 * complexity right now these are only ever freed up when the mux is 149 * shut down. 150 * 151 * At the moment we don't free DLCI objects until the mux is torn down 152 * this avoid object life time issues but might be worth review later. 153 */ 154 155 struct gsm_dlci { 156 struct gsm_mux *gsm; 157 int addr; 158 enum gsm_dlci_state state; 159 struct mutex mutex; 160 161 /* Link layer */ 162 enum gsm_dlci_mode mode; 163 spinlock_t lock; /* Protects the internal state */ 164 struct timer_list t1; /* Retransmit timer for SABM and UA */ 165 int retries; 166 /* Uplink tty if active */ 167 struct tty_port port; /* The tty bound to this DLCI if there is one */ 168 #define TX_SIZE 4096 /* Must be power of 2. */ 169 struct kfifo fifo; /* Queue fifo for the DLCI */ 170 int adaption; /* Adaption layer in use */ 171 int prev_adaption; 172 u32 modem_rx; /* Our incoming virtual modem lines */ 173 u32 modem_tx; /* Our outgoing modem lines */ 174 unsigned int mtu; 175 bool dead; /* Refuse re-open */ 176 /* Configuration */ 177 u8 prio; /* Priority */ 178 u8 ftype; /* Frame type */ 179 u8 k; /* Window size */ 180 /* Flow control */ 181 bool throttled; /* Private copy of throttle state */ 182 bool constipated; /* Throttle status for outgoing */ 183 /* Packetised I/O */ 184 struct sk_buff *skb; /* Frame being sent */ 185 struct sk_buff_head skb_list; /* Queued frames */ 186 /* Data handling callback */ 187 void (*data)(struct gsm_dlci *dlci, const u8 *data, int len); 188 void (*prev_data)(struct gsm_dlci *dlci, const u8 *data, int len); 189 struct net_device *net; /* network interface, if created */ 190 }; 191 192 /* 193 * Parameter bits used for parameter negotiation according to 3GPP 27.010 194 * chapter 5.4.6.3.1. 195 */ 196 197 struct gsm_dlci_param_bits { 198 u8 d_bits; 199 u8 i_cl_bits; 200 u8 p_bits; 201 u8 t_bits; 202 __le16 n_bits; 203 u8 na_bits; 204 u8 k_bits; 205 }; 206 207 static_assert(sizeof(struct gsm_dlci_param_bits) == 8); 208 209 #define PN_D_FIELD_DLCI GENMASK(5, 0) 210 #define PN_I_CL_FIELD_FTYPE GENMASK(3, 0) 211 #define PN_I_CL_FIELD_ADAPTION GENMASK(7, 4) 212 #define PN_P_FIELD_PRIO GENMASK(5, 0) 213 #define PN_T_FIELD_T1 GENMASK(7, 0) 214 #define PN_N_FIELD_N1 GENMASK(15, 0) 215 #define PN_NA_FIELD_N2 GENMASK(7, 0) 216 #define PN_K_FIELD_K GENMASK(2, 0) 217 218 /* Total number of supported devices */ 219 #define GSM_TTY_MINORS 256 220 221 /* DLCI 0, 62/63 are special or reserved see gsmtty_open */ 222 223 #define NUM_DLCI 64 224 225 /* 226 * DLCI 0 is used to pass control blocks out of band of the data 227 * flow (and with a higher link priority). One command can be outstanding 228 * at a time and we use this structure to manage them. They are created 229 * and destroyed by the user context, and updated by the receive paths 230 * and timers 231 */ 232 233 struct gsm_control { 234 u8 cmd; /* Command we are issuing */ 235 u8 *data; /* Data for the command in case we retransmit */ 236 int len; /* Length of block for retransmission */ 237 int done; /* Done flag */ 238 int error; /* Error if any */ 239 }; 240 241 enum gsm_encoding { 242 GSM_BASIC_OPT, 243 GSM_ADV_OPT, 244 }; 245 246 enum gsm_mux_state { 247 GSM_SEARCH, 248 GSM0_ADDRESS, 249 GSM0_CONTROL, 250 GSM0_LEN0, 251 GSM0_LEN1, 252 GSM0_DATA, 253 GSM0_FCS, 254 GSM0_SSOF, 255 GSM1_START, 256 GSM1_ADDRESS, 257 GSM1_CONTROL, 258 GSM1_DATA, 259 GSM1_OVERRUN, 260 }; 261 262 /* 263 * Each GSM mux we have is represented by this structure. If we are 264 * operating as an ldisc then we use this structure as our ldisc 265 * state. We need to sort out lifetimes and locking with respect 266 * to the gsm mux array. For now we don't free DLCI objects that 267 * have been instantiated until the mux itself is terminated. 268 * 269 * To consider further: tty open versus mux shutdown. 270 */ 271 272 struct gsm_mux { 273 struct tty_struct *tty; /* The tty our ldisc is bound to */ 274 spinlock_t lock; 275 struct mutex mutex; 276 unsigned int num; 277 struct kref ref; 278 279 /* Events on the GSM channel */ 280 wait_queue_head_t event; 281 282 /* ldisc send work */ 283 struct work_struct tx_work; 284 285 /* Bits for GSM mode decoding */ 286 287 /* Framing Layer */ 288 u8 *buf; 289 enum gsm_mux_state state; 290 unsigned int len; 291 unsigned int address; 292 unsigned int count; 293 bool escape; 294 enum gsm_encoding encoding; 295 u8 control; 296 u8 fcs; 297 u8 *txframe; /* TX framing buffer */ 298 299 /* Method for the receiver side */ 300 void (*receive)(struct gsm_mux *gsm, u8 ch); 301 302 /* Link Layer */ 303 unsigned int mru; 304 unsigned int mtu; 305 int initiator; /* Did we initiate connection */ 306 bool dead; /* Has the mux been shut down */ 307 struct gsm_dlci *dlci[NUM_DLCI]; 308 int old_c_iflag; /* termios c_iflag value before attach */ 309 bool constipated; /* Asked by remote to shut up */ 310 bool has_devices; /* Devices were registered */ 311 312 spinlock_t tx_lock; 313 unsigned int tx_bytes; /* TX data outstanding */ 314 #define TX_THRESH_HI 8192 315 #define TX_THRESH_LO 2048 316 struct list_head tx_ctrl_list; /* Pending control packets */ 317 struct list_head tx_data_list; /* Pending data packets */ 318 319 /* Control messages */ 320 struct timer_list kick_timer; /* Kick TX queuing on timeout */ 321 struct timer_list t2_timer; /* Retransmit timer for commands */ 322 int cretries; /* Command retry counter */ 323 struct gsm_control *pending_cmd;/* Our current pending command */ 324 spinlock_t control_lock; /* Protects the pending command */ 325 326 /* Keep-alive */ 327 struct timer_list ka_timer; /* Keep-alive response timer */ 328 u8 ka_num; /* Keep-alive match pattern */ 329 signed int ka_retries; /* Keep-alive retry counter, -1 if not yet initialized */ 330 331 /* Configuration */ 332 int adaption; /* 1 or 2 supported */ 333 u8 ftype; /* UI or UIH */ 334 int t1, t2; /* Timers in 1/100th of a sec */ 335 unsigned int t3; /* Power wake-up timer in seconds. */ 336 int n2; /* Retry count */ 337 u8 k; /* Window size */ 338 bool wait_config; /* Wait for configuration by ioctl before DLCI open */ 339 u32 keep_alive; /* Control channel keep-alive in 10ms */ 340 341 /* Statistics (not currently exposed) */ 342 unsigned long bad_fcs; 343 unsigned long malformed; 344 unsigned long io_error; 345 unsigned long open_error; 346 unsigned long bad_size; 347 unsigned long unsupported; 348 }; 349 350 351 /* 352 * Mux objects - needed so that we can translate a tty index into the 353 * relevant mux and DLCI. 354 */ 355 356 #define MAX_MUX 4 /* 256 minors */ 357 static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */ 358 static DEFINE_SPINLOCK(gsm_mux_lock); 359 360 static struct tty_driver *gsm_tty_driver; 361 362 /* 363 * This section of the driver logic implements the GSM encodings 364 * both the basic and the 'advanced'. Reliable transport is not 365 * supported. 366 */ 367 368 #define CR 0x02 369 #define EA 0x01 370 #define PF 0x10 371 372 /* I is special: the rest are ..*/ 373 #define RR 0x01 374 #define UI 0x03 375 #define RNR 0x05 376 #define REJ 0x09 377 #define DM 0x0F 378 #define SABM 0x2F 379 #define DISC 0x43 380 #define UA 0x63 381 #define UIH 0xEF 382 383 /* Channel commands */ 384 #define CMD_NSC 0x09 385 #define CMD_TEST 0x11 386 #define CMD_PSC 0x21 387 #define CMD_RLS 0x29 388 #define CMD_FCOFF 0x31 389 #define CMD_PN 0x41 390 #define CMD_RPN 0x49 391 #define CMD_FCON 0x51 392 #define CMD_CLD 0x61 393 #define CMD_SNC 0x69 394 #define CMD_MSC 0x71 395 396 /* Virtual modem bits */ 397 #define MDM_FC 0x01 398 #define MDM_RTC 0x02 399 #define MDM_RTR 0x04 400 #define MDM_IC 0x20 401 #define MDM_DV 0x40 402 403 #define GSM0_SOF 0xF9 404 #define GSM1_SOF 0x7E 405 #define GSM1_ESCAPE 0x7D 406 #define GSM1_ESCAPE_BITS 0x20 407 #define XON 0x11 408 #define XOFF 0x13 409 #define ISO_IEC_646_MASK 0x7F 410 411 static const struct tty_port_operations gsm_port_ops; 412 413 /* 414 * CRC table for GSM 0710 415 */ 416 417 static const u8 gsm_fcs8[256] = { 418 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75, 419 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B, 420 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69, 421 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67, 422 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D, 423 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43, 424 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51, 425 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F, 426 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05, 427 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B, 428 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19, 429 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17, 430 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D, 431 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33, 432 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21, 433 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F, 434 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95, 435 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B, 436 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89, 437 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87, 438 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD, 439 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3, 440 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1, 441 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF, 442 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5, 443 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB, 444 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9, 445 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7, 446 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD, 447 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3, 448 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1, 449 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF 450 }; 451 452 #define INIT_FCS 0xFF 453 #define GOOD_FCS 0xCF 454 455 static void gsm_dlci_close(struct gsm_dlci *dlci); 456 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len); 457 static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk); 458 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len, 459 u8 ctrl); 460 static int gsm_send_packet(struct gsm_mux *gsm, struct gsm_msg *msg); 461 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr); 462 static void gsmld_write_trigger(struct gsm_mux *gsm); 463 static void gsmld_write_task(struct work_struct *work); 464 465 /** 466 * gsm_fcs_add - update FCS 467 * @fcs: Current FCS 468 * @c: Next data 469 * 470 * Update the FCS to include c. Uses the algorithm in the specification 471 * notes. 472 */ 473 474 static inline u8 gsm_fcs_add(u8 fcs, u8 c) 475 { 476 return gsm_fcs8[fcs ^ c]; 477 } 478 479 /** 480 * gsm_fcs_add_block - update FCS for a block 481 * @fcs: Current FCS 482 * @c: buffer of data 483 * @len: length of buffer 484 * 485 * Update the FCS to include c. Uses the algorithm in the specification 486 * notes. 487 */ 488 489 static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len) 490 { 491 while (len--) 492 fcs = gsm_fcs8[fcs ^ *c++]; 493 return fcs; 494 } 495 496 /** 497 * gsm_read_ea - read a byte into an EA 498 * @val: variable holding value 499 * @c: byte going into the EA 500 * 501 * Processes one byte of an EA. Updates the passed variable 502 * and returns 1 if the EA is now completely read 503 */ 504 505 static int gsm_read_ea(unsigned int *val, u8 c) 506 { 507 /* Add the next 7 bits into the value */ 508 *val <<= 7; 509 *val |= c >> 1; 510 /* Was this the last byte of the EA 1 = yes*/ 511 return c & EA; 512 } 513 514 /** 515 * gsm_read_ea_val - read a value until EA 516 * @val: variable holding value 517 * @data: buffer of data 518 * @dlen: length of data 519 * 520 * Processes an EA value. Updates the passed variable and 521 * returns the processed data length. 522 */ 523 static unsigned int gsm_read_ea_val(unsigned int *val, const u8 *data, int dlen) 524 { 525 unsigned int len = 0; 526 527 for (; dlen > 0; dlen--) { 528 len++; 529 if (gsm_read_ea(val, *data++)) 530 break; 531 } 532 return len; 533 } 534 535 /** 536 * gsm_encode_modem - encode modem data bits 537 * @dlci: DLCI to encode from 538 * 539 * Returns the correct GSM encoded modem status bits (6 bit field) for 540 * the current status of the DLCI and attached tty object 541 */ 542 543 static u8 gsm_encode_modem(const struct gsm_dlci *dlci) 544 { 545 u8 modembits = 0; 546 /* FC is true flow control not modem bits */ 547 if (dlci->throttled) 548 modembits |= MDM_FC; 549 if (dlci->modem_tx & TIOCM_DTR) 550 modembits |= MDM_RTC; 551 if (dlci->modem_tx & TIOCM_RTS) 552 modembits |= MDM_RTR; 553 if (dlci->modem_tx & TIOCM_RI) 554 modembits |= MDM_IC; 555 if (dlci->modem_tx & TIOCM_CD || dlci->gsm->initiator) 556 modembits |= MDM_DV; 557 /* special mappings for passive side to operate as UE */ 558 if (dlci->modem_tx & TIOCM_OUT1) 559 modembits |= MDM_IC; 560 if (dlci->modem_tx & TIOCM_OUT2) 561 modembits |= MDM_DV; 562 return modembits; 563 } 564 565 static void gsm_hex_dump_bytes(const char *fname, const u8 *data, 566 unsigned long len) 567 { 568 char *prefix; 569 570 if (!fname) { 571 print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, 16, 1, data, len, 572 true); 573 return; 574 } 575 576 prefix = kasprintf(GFP_ATOMIC, "%s: ", fname); 577 if (!prefix) 578 return; 579 print_hex_dump(KERN_INFO, prefix, DUMP_PREFIX_OFFSET, 16, 1, data, len, 580 true); 581 kfree(prefix); 582 } 583 584 /** 585 * gsm_encode_params - encode DLCI parameters 586 * @dlci: DLCI to encode from 587 * @params: buffer to fill with the encoded parameters 588 * 589 * Encodes the parameters according to GSM 07.10 section 5.4.6.3.1 590 * table 3. 591 */ 592 static int gsm_encode_params(const struct gsm_dlci *dlci, 593 struct gsm_dlci_param_bits *params) 594 { 595 const struct gsm_mux *gsm = dlci->gsm; 596 unsigned int i, cl; 597 598 switch (dlci->ftype) { 599 case UIH: 600 i = 0; /* UIH */ 601 break; 602 case UI: 603 i = 1; /* UI */ 604 break; 605 default: 606 pr_debug("unsupported frame type %d\n", dlci->ftype); 607 return -EINVAL; 608 } 609 610 switch (dlci->adaption) { 611 case 1: /* Unstructured */ 612 cl = 0; /* convergence layer type 1 */ 613 break; 614 case 2: /* Unstructured with modem bits. */ 615 cl = 1; /* convergence layer type 2 */ 616 break; 617 default: 618 pr_debug("unsupported adaption %d\n", dlci->adaption); 619 return -EINVAL; 620 } 621 622 params->d_bits = FIELD_PREP(PN_D_FIELD_DLCI, dlci->addr); 623 /* UIH, convergence layer type 1 */ 624 params->i_cl_bits = FIELD_PREP(PN_I_CL_FIELD_FTYPE, i) | 625 FIELD_PREP(PN_I_CL_FIELD_ADAPTION, cl); 626 params->p_bits = FIELD_PREP(PN_P_FIELD_PRIO, dlci->prio); 627 params->t_bits = FIELD_PREP(PN_T_FIELD_T1, gsm->t1); 628 params->n_bits = cpu_to_le16(FIELD_PREP(PN_N_FIELD_N1, dlci->mtu)); 629 params->na_bits = FIELD_PREP(PN_NA_FIELD_N2, gsm->n2); 630 params->k_bits = FIELD_PREP(PN_K_FIELD_K, dlci->k); 631 632 return 0; 633 } 634 635 /** 636 * gsm_register_devices - register all tty devices for a given mux index 637 * 638 * @driver: the tty driver that describes the tty devices 639 * @index: the mux number is used to calculate the minor numbers of the 640 * ttys for this mux and may differ from the position in the 641 * mux array. 642 */ 643 static int gsm_register_devices(struct tty_driver *driver, unsigned int index) 644 { 645 struct device *dev; 646 int i; 647 unsigned int base; 648 649 if (!driver || index >= MAX_MUX) 650 return -EINVAL; 651 652 base = index * NUM_DLCI; /* first minor for this index */ 653 for (i = 1; i < NUM_DLCI; i++) { 654 /* Don't register device 0 - this is the control channel 655 * and not a usable tty interface 656 */ 657 dev = tty_register_device(gsm_tty_driver, base + i, NULL); 658 if (IS_ERR(dev)) { 659 if (debug & DBG_ERRORS) 660 pr_info("%s failed to register device minor %u", 661 __func__, base + i); 662 for (i--; i >= 1; i--) 663 tty_unregister_device(gsm_tty_driver, base + i); 664 return PTR_ERR(dev); 665 } 666 } 667 668 return 0; 669 } 670 671 /** 672 * gsm_unregister_devices - unregister all tty devices for a given mux index 673 * 674 * @driver: the tty driver that describes the tty devices 675 * @index: the mux number is used to calculate the minor numbers of the 676 * ttys for this mux and may differ from the position in the 677 * mux array. 678 */ 679 static void gsm_unregister_devices(struct tty_driver *driver, 680 unsigned int index) 681 { 682 int i; 683 unsigned int base; 684 685 if (!driver || index >= MAX_MUX) 686 return; 687 688 base = index * NUM_DLCI; /* first minor for this index */ 689 for (i = 1; i < NUM_DLCI; i++) { 690 /* Don't unregister device 0 - this is the control 691 * channel and not a usable tty interface 692 */ 693 tty_unregister_device(gsm_tty_driver, base + i); 694 } 695 } 696 697 /** 698 * gsm_print_packet - display a frame for debug 699 * @hdr: header to print before decode 700 * @addr: address EA from the frame 701 * @cr: C/R bit seen as initiator 702 * @control: control including PF bit 703 * @data: following data bytes 704 * @dlen: length of data 705 * 706 * Displays a packet in human readable format for debugging purposes. The 707 * style is based on amateur radio LAP-B dump display. 708 */ 709 710 static void gsm_print_packet(const char *hdr, int addr, int cr, 711 u8 control, const u8 *data, int dlen) 712 { 713 if (!(debug & DBG_DUMP)) 714 return; 715 /* Only show user payload frames if debug & DBG_PAYLOAD */ 716 if (!(debug & DBG_PAYLOAD) && addr != 0) 717 if ((control & ~PF) == UI || (control & ~PF) == UIH) 718 return; 719 720 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]); 721 722 switch (control & ~PF) { 723 case SABM: 724 pr_cont("SABM"); 725 break; 726 case UA: 727 pr_cont("UA"); 728 break; 729 case DISC: 730 pr_cont("DISC"); 731 break; 732 case DM: 733 pr_cont("DM"); 734 break; 735 case UI: 736 pr_cont("UI"); 737 break; 738 case UIH: 739 pr_cont("UIH"); 740 break; 741 default: 742 if (!(control & 0x01)) { 743 pr_cont("I N(S)%d N(R)%d", 744 (control & 0x0E) >> 1, (control & 0xE0) >> 5); 745 } else switch (control & 0x0F) { 746 case RR: 747 pr_cont("RR(%d)", (control & 0xE0) >> 5); 748 break; 749 case RNR: 750 pr_cont("RNR(%d)", (control & 0xE0) >> 5); 751 break; 752 case REJ: 753 pr_cont("REJ(%d)", (control & 0xE0) >> 5); 754 break; 755 default: 756 pr_cont("[%02X]", control); 757 } 758 } 759 760 if (control & PF) 761 pr_cont("(P)"); 762 else 763 pr_cont("(F)"); 764 765 gsm_hex_dump_bytes(NULL, data, dlen); 766 } 767 768 769 /* 770 * Link level transmission side 771 */ 772 773 /** 774 * gsm_stuff_frame - bytestuff a packet 775 * @input: input buffer 776 * @output: output buffer 777 * @len: length of input 778 * 779 * Expand a buffer by bytestuffing it. The worst case size change 780 * is doubling and the caller is responsible for handing out 781 * suitable sized buffers. 782 */ 783 784 static int gsm_stuff_frame(const u8 *input, u8 *output, int len) 785 { 786 int olen = 0; 787 while (len--) { 788 if (*input == GSM1_SOF || *input == GSM1_ESCAPE 789 || (*input & ISO_IEC_646_MASK) == XON 790 || (*input & ISO_IEC_646_MASK) == XOFF) { 791 *output++ = GSM1_ESCAPE; 792 *output++ = *input++ ^ GSM1_ESCAPE_BITS; 793 olen++; 794 } else 795 *output++ = *input++; 796 olen++; 797 } 798 return olen; 799 } 800 801 /** 802 * gsm_send - send a control frame 803 * @gsm: our GSM mux 804 * @addr: address for control frame 805 * @cr: command/response bit seen as initiator 806 * @control: control byte including PF bit 807 * 808 * Format up and transmit a control frame. These should be transmitted 809 * ahead of data when they are needed. 810 */ 811 static int gsm_send(struct gsm_mux *gsm, int addr, int cr, int control) 812 { 813 struct gsm_msg *msg; 814 u8 *dp; 815 int ocr; 816 unsigned long flags; 817 818 msg = gsm_data_alloc(gsm, addr, 0, control); 819 if (!msg) 820 return -ENOMEM; 821 822 /* toggle C/R coding if not initiator */ 823 ocr = cr ^ (gsm->initiator ? 0 : 1); 824 825 msg->data -= 3; 826 dp = msg->data; 827 *dp++ = (addr << 2) | (ocr << 1) | EA; 828 *dp++ = control; 829 830 if (gsm->encoding == GSM_BASIC_OPT) 831 *dp++ = EA; /* Length of data = 0 */ 832 833 *dp = 0xFF - gsm_fcs_add_block(INIT_FCS, msg->data, dp - msg->data); 834 msg->len = (dp - msg->data) + 1; 835 836 gsm_print_packet("Q->", addr, cr, control, NULL, 0); 837 838 spin_lock_irqsave(&gsm->tx_lock, flags); 839 list_add_tail(&msg->list, &gsm->tx_ctrl_list); 840 gsm->tx_bytes += msg->len; 841 spin_unlock_irqrestore(&gsm->tx_lock, flags); 842 gsmld_write_trigger(gsm); 843 844 return 0; 845 } 846 847 /** 848 * gsm_dlci_clear_queues - remove outstanding data for a DLCI 849 * @gsm: mux 850 * @dlci: clear for this DLCI 851 * 852 * Clears the data queues for a given DLCI. 853 */ 854 static void gsm_dlci_clear_queues(struct gsm_mux *gsm, struct gsm_dlci *dlci) 855 { 856 struct gsm_msg *msg, *nmsg; 857 int addr = dlci->addr; 858 unsigned long flags; 859 860 /* Clear DLCI write fifo first */ 861 spin_lock_irqsave(&dlci->lock, flags); 862 kfifo_reset(&dlci->fifo); 863 spin_unlock_irqrestore(&dlci->lock, flags); 864 865 /* Clear data packets in MUX write queue */ 866 spin_lock_irqsave(&gsm->tx_lock, flags); 867 list_for_each_entry_safe(msg, nmsg, &gsm->tx_data_list, list) { 868 if (msg->addr != addr) 869 continue; 870 gsm->tx_bytes -= msg->len; 871 list_del(&msg->list); 872 kfree(msg); 873 } 874 spin_unlock_irqrestore(&gsm->tx_lock, flags); 875 } 876 877 /** 878 * gsm_response - send a control response 879 * @gsm: our GSM mux 880 * @addr: address for control frame 881 * @control: control byte including PF bit 882 * 883 * Format up and transmit a link level response frame. 884 */ 885 886 static inline void gsm_response(struct gsm_mux *gsm, int addr, int control) 887 { 888 gsm_send(gsm, addr, 0, control); 889 } 890 891 /** 892 * gsm_command - send a control command 893 * @gsm: our GSM mux 894 * @addr: address for control frame 895 * @control: control byte including PF bit 896 * 897 * Format up and transmit a link level command frame. 898 */ 899 900 static inline void gsm_command(struct gsm_mux *gsm, int addr, int control) 901 { 902 gsm_send(gsm, addr, 1, control); 903 } 904 905 /* Data transmission */ 906 907 #define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */ 908 909 /** 910 * gsm_data_alloc - allocate data frame 911 * @gsm: GSM mux 912 * @addr: DLCI address 913 * @len: length excluding header and FCS 914 * @ctrl: control byte 915 * 916 * Allocate a new data buffer for sending frames with data. Space is left 917 * at the front for header bytes but that is treated as an implementation 918 * detail and not for the high level code to use 919 */ 920 921 static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len, 922 u8 ctrl) 923 { 924 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN, 925 GFP_ATOMIC); 926 if (m == NULL) 927 return NULL; 928 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */ 929 m->len = len; 930 m->addr = addr; 931 m->ctrl = ctrl; 932 INIT_LIST_HEAD(&m->list); 933 return m; 934 } 935 936 /** 937 * gsm_send_packet - sends a single packet 938 * @gsm: GSM Mux 939 * @msg: packet to send 940 * 941 * The given packet is encoded and sent out. No memory is freed. 942 * The caller must hold the gsm tx lock. 943 */ 944 static int gsm_send_packet(struct gsm_mux *gsm, struct gsm_msg *msg) 945 { 946 int len, ret; 947 948 949 if (gsm->encoding == GSM_BASIC_OPT) { 950 gsm->txframe[0] = GSM0_SOF; 951 memcpy(gsm->txframe + 1, msg->data, msg->len); 952 gsm->txframe[msg->len + 1] = GSM0_SOF; 953 len = msg->len + 2; 954 } else { 955 gsm->txframe[0] = GSM1_SOF; 956 len = gsm_stuff_frame(msg->data, gsm->txframe + 1, msg->len); 957 gsm->txframe[len + 1] = GSM1_SOF; 958 len += 2; 959 } 960 961 if (debug & DBG_DATA) 962 gsm_hex_dump_bytes(__func__, gsm->txframe, len); 963 gsm_print_packet("-->", msg->addr, gsm->initiator, msg->ctrl, msg->data, 964 msg->len); 965 966 ret = gsmld_output(gsm, gsm->txframe, len); 967 if (ret <= 0) 968 return ret; 969 /* FIXME: Can eliminate one SOF in many more cases */ 970 gsm->tx_bytes -= msg->len; 971 972 return 0; 973 } 974 975 /** 976 * gsm_is_flow_ctrl_msg - checks if flow control message 977 * @msg: message to check 978 * 979 * Returns true if the given message is a flow control command of the 980 * control channel. False is returned in any other case. 981 */ 982 static bool gsm_is_flow_ctrl_msg(struct gsm_msg *msg) 983 { 984 unsigned int cmd; 985 986 if (msg->addr > 0) 987 return false; 988 989 switch (msg->ctrl & ~PF) { 990 case UI: 991 case UIH: 992 cmd = 0; 993 if (gsm_read_ea_val(&cmd, msg->data + 2, msg->len - 2) < 1) 994 break; 995 switch (cmd & ~PF) { 996 case CMD_FCOFF: 997 case CMD_FCON: 998 return true; 999 } 1000 break; 1001 } 1002 1003 return false; 1004 } 1005 1006 /** 1007 * gsm_data_kick - poke the queue 1008 * @gsm: GSM Mux 1009 * 1010 * The tty device has called us to indicate that room has appeared in 1011 * the transmit queue. Ram more data into the pipe if we have any. 1012 * If we have been flow-stopped by a CMD_FCOFF, then we can only 1013 * send messages on DLCI0 until CMD_FCON. The caller must hold 1014 * the gsm tx lock. 1015 */ 1016 static int gsm_data_kick(struct gsm_mux *gsm) 1017 { 1018 struct gsm_msg *msg, *nmsg; 1019 struct gsm_dlci *dlci; 1020 int ret; 1021 1022 clear_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags); 1023 1024 /* Serialize control messages and control channel messages first */ 1025 list_for_each_entry_safe(msg, nmsg, &gsm->tx_ctrl_list, list) { 1026 if (gsm->constipated && !gsm_is_flow_ctrl_msg(msg)) 1027 continue; 1028 ret = gsm_send_packet(gsm, msg); 1029 switch (ret) { 1030 case -ENOSPC: 1031 return -ENOSPC; 1032 case -ENODEV: 1033 /* ldisc not open */ 1034 gsm->tx_bytes -= msg->len; 1035 list_del(&msg->list); 1036 kfree(msg); 1037 continue; 1038 default: 1039 if (ret >= 0) { 1040 list_del(&msg->list); 1041 kfree(msg); 1042 } 1043 break; 1044 } 1045 } 1046 1047 if (gsm->constipated) 1048 return -EAGAIN; 1049 1050 /* Serialize other channels */ 1051 if (list_empty(&gsm->tx_data_list)) 1052 return 0; 1053 list_for_each_entry_safe(msg, nmsg, &gsm->tx_data_list, list) { 1054 dlci = gsm->dlci[msg->addr]; 1055 /* Send only messages for DLCIs with valid state */ 1056 if (dlci->state != DLCI_OPEN) { 1057 gsm->tx_bytes -= msg->len; 1058 list_del(&msg->list); 1059 kfree(msg); 1060 continue; 1061 } 1062 ret = gsm_send_packet(gsm, msg); 1063 switch (ret) { 1064 case -ENOSPC: 1065 return -ENOSPC; 1066 case -ENODEV: 1067 /* ldisc not open */ 1068 gsm->tx_bytes -= msg->len; 1069 list_del(&msg->list); 1070 kfree(msg); 1071 continue; 1072 default: 1073 if (ret >= 0) { 1074 list_del(&msg->list); 1075 kfree(msg); 1076 } 1077 break; 1078 } 1079 } 1080 1081 return 1; 1082 } 1083 1084 /** 1085 * __gsm_data_queue - queue a UI or UIH frame 1086 * @dlci: DLCI sending the data 1087 * @msg: message queued 1088 * 1089 * Add data to the transmit queue and try and get stuff moving 1090 * out of the mux tty if not already doing so. The Caller must hold 1091 * the gsm tx lock. 1092 */ 1093 1094 static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) 1095 { 1096 struct gsm_mux *gsm = dlci->gsm; 1097 u8 *dp = msg->data; 1098 u8 *fcs = dp + msg->len; 1099 1100 /* Fill in the header */ 1101 if (gsm->encoding == GSM_BASIC_OPT) { 1102 if (msg->len < 128) 1103 *--dp = (msg->len << 1) | EA; 1104 else { 1105 *--dp = (msg->len >> 7); /* bits 7 - 15 */ 1106 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */ 1107 } 1108 } 1109 1110 *--dp = msg->ctrl; 1111 if (gsm->initiator) 1112 *--dp = (msg->addr << 2) | CR | EA; 1113 else 1114 *--dp = (msg->addr << 2) | EA; 1115 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp); 1116 /* Ugly protocol layering violation */ 1117 if (msg->ctrl == UI || msg->ctrl == (UI|PF)) 1118 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len); 1119 *fcs = 0xFF - *fcs; 1120 1121 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl, 1122 msg->data, msg->len); 1123 1124 /* Move the header back and adjust the length, also allow for the FCS 1125 now tacked on the end */ 1126 msg->len += (msg->data - dp) + 1; 1127 msg->data = dp; 1128 1129 /* Add to the actual output queue */ 1130 switch (msg->ctrl & ~PF) { 1131 case UI: 1132 case UIH: 1133 if (msg->addr > 0) { 1134 list_add_tail(&msg->list, &gsm->tx_data_list); 1135 break; 1136 } 1137 fallthrough; 1138 default: 1139 list_add_tail(&msg->list, &gsm->tx_ctrl_list); 1140 break; 1141 } 1142 gsm->tx_bytes += msg->len; 1143 1144 gsmld_write_trigger(gsm); 1145 mod_timer(&gsm->kick_timer, jiffies + 10 * gsm->t1 * HZ / 100); 1146 } 1147 1148 /** 1149 * gsm_data_queue - queue a UI or UIH frame 1150 * @dlci: DLCI sending the data 1151 * @msg: message queued 1152 * 1153 * Add data to the transmit queue and try and get stuff moving 1154 * out of the mux tty if not already doing so. Take the 1155 * the gsm tx lock and dlci lock. 1156 */ 1157 1158 static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) 1159 { 1160 unsigned long flags; 1161 spin_lock_irqsave(&dlci->gsm->tx_lock, flags); 1162 __gsm_data_queue(dlci, msg); 1163 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); 1164 } 1165 1166 /** 1167 * gsm_dlci_data_output - try and push data out of a DLCI 1168 * @gsm: mux 1169 * @dlci: the DLCI to pull data from 1170 * 1171 * Pull data from a DLCI and send it into the transmit queue if there 1172 * is data. Keep to the MRU of the mux. This path handles the usual tty 1173 * interface which is a byte stream with optional modem data. 1174 * 1175 * Caller must hold the tx_lock of the mux. 1176 */ 1177 1178 static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci) 1179 { 1180 struct gsm_msg *msg; 1181 u8 *dp; 1182 int h, len, size; 1183 1184 /* for modem bits without break data */ 1185 h = ((dlci->adaption == 1) ? 0 : 1); 1186 1187 len = kfifo_len(&dlci->fifo); 1188 if (len == 0) 1189 return 0; 1190 1191 /* MTU/MRU count only the data bits but watch adaption mode */ 1192 if ((len + h) > dlci->mtu) 1193 len = dlci->mtu - h; 1194 1195 size = len + h; 1196 1197 msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype); 1198 if (!msg) 1199 return -ENOMEM; 1200 dp = msg->data; 1201 switch (dlci->adaption) { 1202 case 1: /* Unstructured */ 1203 break; 1204 case 2: /* Unstructured with modem bits. 1205 * Always one byte as we never send inline break data 1206 */ 1207 *dp++ = (gsm_encode_modem(dlci) << 1) | EA; 1208 break; 1209 default: 1210 pr_err("%s: unsupported adaption %d\n", __func__, 1211 dlci->adaption); 1212 break; 1213 } 1214 1215 WARN_ON(len != kfifo_out_locked(&dlci->fifo, dp, len, 1216 &dlci->lock)); 1217 1218 /* Notify upper layer about available send space. */ 1219 tty_port_tty_wakeup(&dlci->port); 1220 1221 __gsm_data_queue(dlci, msg); 1222 /* Bytes of data we used up */ 1223 return size; 1224 } 1225 1226 /** 1227 * gsm_dlci_data_output_framed - try and push data out of a DLCI 1228 * @gsm: mux 1229 * @dlci: the DLCI to pull data from 1230 * 1231 * Pull data from a DLCI and send it into the transmit queue if there 1232 * is data. Keep to the MRU of the mux. This path handles framed data 1233 * queued as skbuffs to the DLCI. 1234 * 1235 * Caller must hold the tx_lock of the mux. 1236 */ 1237 1238 static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, 1239 struct gsm_dlci *dlci) 1240 { 1241 struct gsm_msg *msg; 1242 u8 *dp; 1243 int len, size; 1244 int last = 0, first = 0; 1245 int overhead = 0; 1246 1247 /* One byte per frame is used for B/F flags */ 1248 if (dlci->adaption == 4) 1249 overhead = 1; 1250 1251 /* dlci->skb is locked by tx_lock */ 1252 if (dlci->skb == NULL) { 1253 dlci->skb = skb_dequeue_tail(&dlci->skb_list); 1254 if (dlci->skb == NULL) 1255 return 0; 1256 first = 1; 1257 } 1258 len = dlci->skb->len + overhead; 1259 1260 /* MTU/MRU count only the data bits */ 1261 if (len > dlci->mtu) { 1262 if (dlci->adaption == 3) { 1263 /* Over long frame, bin it */ 1264 dev_kfree_skb_any(dlci->skb); 1265 dlci->skb = NULL; 1266 return 0; 1267 } 1268 len = dlci->mtu; 1269 } else 1270 last = 1; 1271 1272 size = len + overhead; 1273 msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype); 1274 if (msg == NULL) { 1275 skb_queue_tail(&dlci->skb_list, dlci->skb); 1276 dlci->skb = NULL; 1277 return -ENOMEM; 1278 } 1279 dp = msg->data; 1280 1281 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */ 1282 /* Flag byte to carry the start/end info */ 1283 *dp++ = last << 7 | first << 6 | 1; /* EA */ 1284 len--; 1285 } 1286 memcpy(dp, dlci->skb->data, len); 1287 skb_pull(dlci->skb, len); 1288 __gsm_data_queue(dlci, msg); 1289 if (last) { 1290 dev_kfree_skb_any(dlci->skb); 1291 dlci->skb = NULL; 1292 } 1293 return size; 1294 } 1295 1296 /** 1297 * gsm_dlci_modem_output - try and push modem status out of a DLCI 1298 * @gsm: mux 1299 * @dlci: the DLCI to pull modem status from 1300 * @brk: break signal 1301 * 1302 * Push an empty frame in to the transmit queue to update the modem status 1303 * bits and to transmit an optional break. 1304 * 1305 * Caller must hold the tx_lock of the mux. 1306 */ 1307 1308 static int gsm_dlci_modem_output(struct gsm_mux *gsm, struct gsm_dlci *dlci, 1309 u8 brk) 1310 { 1311 u8 *dp = NULL; 1312 struct gsm_msg *msg; 1313 int size = 0; 1314 1315 /* for modem bits without break data */ 1316 switch (dlci->adaption) { 1317 case 1: /* Unstructured */ 1318 break; 1319 case 2: /* Unstructured with modem bits. */ 1320 size++; 1321 if (brk > 0) 1322 size++; 1323 break; 1324 default: 1325 pr_err("%s: unsupported adaption %d\n", __func__, 1326 dlci->adaption); 1327 return -EINVAL; 1328 } 1329 1330 msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype); 1331 if (!msg) { 1332 pr_err("%s: gsm_data_alloc error", __func__); 1333 return -ENOMEM; 1334 } 1335 dp = msg->data; 1336 switch (dlci->adaption) { 1337 case 1: /* Unstructured */ 1338 break; 1339 case 2: /* Unstructured with modem bits. */ 1340 if (brk == 0) { 1341 *dp++ = (gsm_encode_modem(dlci) << 1) | EA; 1342 } else { 1343 *dp++ = gsm_encode_modem(dlci) << 1; 1344 *dp++ = (brk << 4) | 2 | EA; /* Length, Break, EA */ 1345 } 1346 break; 1347 default: 1348 /* Handled above */ 1349 break; 1350 } 1351 1352 __gsm_data_queue(dlci, msg); 1353 return size; 1354 } 1355 1356 /** 1357 * gsm_dlci_data_sweep - look for data to send 1358 * @gsm: the GSM mux 1359 * 1360 * Sweep the GSM mux channels in priority order looking for ones with 1361 * data to send. We could do with optimising this scan a bit. We aim 1362 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit 1363 * TX_THRESH_LO we get called again 1364 * 1365 * FIXME: We should round robin between groups and in theory you can 1366 * renegotiate DLCI priorities with optional stuff. Needs optimising. 1367 */ 1368 1369 static int gsm_dlci_data_sweep(struct gsm_mux *gsm) 1370 { 1371 /* Priority ordering: We should do priority with RR of the groups */ 1372 int i, len, ret = 0; 1373 bool sent; 1374 struct gsm_dlci *dlci; 1375 1376 while (gsm->tx_bytes < TX_THRESH_HI) { 1377 for (sent = false, i = 1; i < NUM_DLCI; i++) { 1378 dlci = gsm->dlci[i]; 1379 /* skip unused or blocked channel */ 1380 if (!dlci || dlci->constipated) 1381 continue; 1382 /* skip channels with invalid state */ 1383 if (dlci->state != DLCI_OPEN) 1384 continue; 1385 /* count the sent data per adaption */ 1386 if (dlci->adaption < 3 && !dlci->net) 1387 len = gsm_dlci_data_output(gsm, dlci); 1388 else 1389 len = gsm_dlci_data_output_framed(gsm, dlci); 1390 /* on error exit */ 1391 if (len < 0) 1392 return ret; 1393 if (len > 0) { 1394 ret++; 1395 sent = true; 1396 /* The lower DLCs can starve the higher DLCs! */ 1397 break; 1398 } 1399 /* try next */ 1400 } 1401 if (!sent) 1402 break; 1403 } 1404 1405 return ret; 1406 } 1407 1408 /** 1409 * gsm_dlci_data_kick - transmit if possible 1410 * @dlci: DLCI to kick 1411 * 1412 * Transmit data from this DLCI if the queue is empty. We can't rely on 1413 * a tty wakeup except when we filled the pipe so we need to fire off 1414 * new data ourselves in other cases. 1415 */ 1416 1417 static void gsm_dlci_data_kick(struct gsm_dlci *dlci) 1418 { 1419 unsigned long flags; 1420 int sweep; 1421 1422 if (dlci->constipated) 1423 return; 1424 1425 spin_lock_irqsave(&dlci->gsm->tx_lock, flags); 1426 /* If we have nothing running then we need to fire up */ 1427 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO); 1428 if (dlci->gsm->tx_bytes == 0) { 1429 if (dlci->net) 1430 gsm_dlci_data_output_framed(dlci->gsm, dlci); 1431 else 1432 gsm_dlci_data_output(dlci->gsm, dlci); 1433 } 1434 if (sweep) 1435 gsm_dlci_data_sweep(dlci->gsm); 1436 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); 1437 } 1438 1439 /* 1440 * Control message processing 1441 */ 1442 1443 1444 /** 1445 * gsm_control_command - send a command frame to a control 1446 * @gsm: gsm channel 1447 * @cmd: the command to use 1448 * @data: data to follow encoded info 1449 * @dlen: length of data 1450 * 1451 * Encode up and queue a UI/UIH frame containing our command. 1452 */ 1453 static int gsm_control_command(struct gsm_mux *gsm, int cmd, const u8 *data, 1454 int dlen) 1455 { 1456 struct gsm_msg *msg; 1457 struct gsm_dlci *dlci = gsm->dlci[0]; 1458 1459 msg = gsm_data_alloc(gsm, 0, dlen + 2, dlci->ftype); 1460 if (msg == NULL) 1461 return -ENOMEM; 1462 1463 msg->data[0] = (cmd << 1) | CR | EA; /* Set C/R */ 1464 msg->data[1] = (dlen << 1) | EA; 1465 memcpy(msg->data + 2, data, dlen); 1466 gsm_data_queue(dlci, msg); 1467 1468 return 0; 1469 } 1470 1471 /** 1472 * gsm_control_reply - send a response frame to a control 1473 * @gsm: gsm channel 1474 * @cmd: the command to use 1475 * @data: data to follow encoded info 1476 * @dlen: length of data 1477 * 1478 * Encode up and queue a UI/UIH frame containing our response. 1479 */ 1480 1481 static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data, 1482 int dlen) 1483 { 1484 struct gsm_msg *msg; 1485 struct gsm_dlci *dlci = gsm->dlci[0]; 1486 1487 msg = gsm_data_alloc(gsm, 0, dlen + 2, dlci->ftype); 1488 if (msg == NULL) 1489 return; 1490 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */ 1491 msg->data[1] = (dlen << 1) | EA; 1492 memcpy(msg->data + 2, data, dlen); 1493 gsm_data_queue(dlci, msg); 1494 } 1495 1496 /** 1497 * gsm_process_modem - process received modem status 1498 * @tty: virtual tty bound to the DLCI 1499 * @dlci: DLCI to affect 1500 * @modem: modem bits (full EA) 1501 * @slen: number of signal octets 1502 * 1503 * Used when a modem control message or line state inline in adaption 1504 * layer 2 is processed. Sort out the local modem state and throttles 1505 */ 1506 1507 static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci, 1508 u32 modem, int slen) 1509 { 1510 int mlines = 0; 1511 u8 brk = 0; 1512 int fc; 1513 1514 /* The modem status command can either contain one octet (V.24 signals) 1515 * or two octets (V.24 signals + break signals). This is specified in 1516 * section 5.4.6.3.7 of the 07.10 mux spec. 1517 */ 1518 1519 if (slen == 1) 1520 modem = modem & 0x7f; 1521 else { 1522 brk = modem & 0x7f; 1523 modem = (modem >> 7) & 0x7f; 1524 } 1525 1526 /* Flow control/ready to communicate */ 1527 fc = (modem & MDM_FC) || !(modem & MDM_RTR); 1528 if (fc && !dlci->constipated) { 1529 /* Need to throttle our output on this device */ 1530 dlci->constipated = true; 1531 } else if (!fc && dlci->constipated) { 1532 dlci->constipated = false; 1533 gsm_dlci_data_kick(dlci); 1534 } 1535 1536 /* Map modem bits */ 1537 if (modem & MDM_RTC) 1538 mlines |= TIOCM_DSR | TIOCM_DTR; 1539 if (modem & MDM_RTR) 1540 mlines |= TIOCM_RTS | TIOCM_CTS; 1541 if (modem & MDM_IC) 1542 mlines |= TIOCM_RI; 1543 if (modem & MDM_DV) 1544 mlines |= TIOCM_CD; 1545 1546 /* Carrier drop -> hangup */ 1547 if (tty) { 1548 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD)) 1549 if (!C_CLOCAL(tty)) 1550 tty_hangup(tty); 1551 } 1552 if (brk & 0x01) 1553 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK); 1554 dlci->modem_rx = mlines; 1555 wake_up_interruptible(&dlci->gsm->event); 1556 } 1557 1558 /** 1559 * gsm_process_negotiation - process received parameters 1560 * @gsm: GSM channel 1561 * @addr: DLCI address 1562 * @cr: command/response 1563 * @params: encoded parameters from the parameter negotiation message 1564 * 1565 * Used when the response for our parameter negotiation command was 1566 * received. 1567 */ 1568 static int gsm_process_negotiation(struct gsm_mux *gsm, unsigned int addr, 1569 unsigned int cr, 1570 const struct gsm_dlci_param_bits *params) 1571 { 1572 struct gsm_dlci *dlci = gsm->dlci[addr]; 1573 unsigned int ftype, i, adaption, prio, n1, k; 1574 1575 i = FIELD_GET(PN_I_CL_FIELD_FTYPE, params->i_cl_bits); 1576 adaption = FIELD_GET(PN_I_CL_FIELD_ADAPTION, params->i_cl_bits) + 1; 1577 prio = FIELD_GET(PN_P_FIELD_PRIO, params->p_bits); 1578 n1 = FIELD_GET(PN_N_FIELD_N1, get_unaligned_le16(¶ms->n_bits)); 1579 k = FIELD_GET(PN_K_FIELD_K, params->k_bits); 1580 1581 if (n1 < MIN_MTU) { 1582 if (debug & DBG_ERRORS) 1583 pr_info("%s N1 out of range in PN\n", __func__); 1584 return -EINVAL; 1585 } 1586 1587 switch (i) { 1588 case 0x00: 1589 ftype = UIH; 1590 break; 1591 case 0x01: 1592 ftype = UI; 1593 break; 1594 case 0x02: /* I frames are not supported */ 1595 if (debug & DBG_ERRORS) 1596 pr_info("%s unsupported I frame request in PN\n", 1597 __func__); 1598 gsm->unsupported++; 1599 return -EINVAL; 1600 default: 1601 if (debug & DBG_ERRORS) 1602 pr_info("%s i out of range in PN\n", __func__); 1603 return -EINVAL; 1604 } 1605 1606 if (!cr && gsm->initiator) { 1607 if (adaption != dlci->adaption) { 1608 if (debug & DBG_ERRORS) 1609 pr_info("%s invalid adaption %d in PN\n", 1610 __func__, adaption); 1611 return -EINVAL; 1612 } 1613 if (prio != dlci->prio) { 1614 if (debug & DBG_ERRORS) 1615 pr_info("%s invalid priority %d in PN", 1616 __func__, prio); 1617 return -EINVAL; 1618 } 1619 if (n1 > gsm->mru || n1 > dlci->mtu) { 1620 /* We requested a frame size but the other party wants 1621 * to send larger frames. The standard allows only a 1622 * smaller response value than requested (5.4.6.3.1). 1623 */ 1624 if (debug & DBG_ERRORS) 1625 pr_info("%s invalid N1 %d in PN\n", __func__, 1626 n1); 1627 return -EINVAL; 1628 } 1629 dlci->mtu = n1; 1630 if (ftype != dlci->ftype) { 1631 if (debug & DBG_ERRORS) 1632 pr_info("%s invalid i %d in PN\n", __func__, i); 1633 return -EINVAL; 1634 } 1635 if (ftype != UI && ftype != UIH && k > dlci->k) { 1636 if (debug & DBG_ERRORS) 1637 pr_info("%s invalid k %d in PN\n", __func__, k); 1638 return -EINVAL; 1639 } 1640 dlci->k = k; 1641 } else if (cr && !gsm->initiator) { 1642 /* Only convergence layer type 1 and 2 are supported. */ 1643 if (adaption != 1 && adaption != 2) { 1644 if (debug & DBG_ERRORS) 1645 pr_info("%s invalid adaption %d in PN\n", 1646 __func__, adaption); 1647 return -EINVAL; 1648 } 1649 dlci->adaption = adaption; 1650 if (n1 > gsm->mru) { 1651 /* Propose a smaller value */ 1652 dlci->mtu = gsm->mru; 1653 } else if (n1 > MAX_MTU) { 1654 /* Propose a smaller value */ 1655 dlci->mtu = MAX_MTU; 1656 } else { 1657 dlci->mtu = n1; 1658 } 1659 dlci->prio = prio; 1660 dlci->ftype = ftype; 1661 dlci->k = k; 1662 } else { 1663 return -EINVAL; 1664 } 1665 1666 return 0; 1667 } 1668 1669 /** 1670 * gsm_control_modem - modem status received 1671 * @gsm: GSM channel 1672 * @data: data following command 1673 * @clen: command length 1674 * 1675 * We have received a modem status control message. This is used by 1676 * the GSM mux protocol to pass virtual modem line status and optionally 1677 * to indicate break signals. Unpack it, convert to Linux representation 1678 * and if need be stuff a break message down the tty. 1679 */ 1680 1681 static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen) 1682 { 1683 unsigned int addr = 0; 1684 unsigned int modem = 0; 1685 struct gsm_dlci *dlci; 1686 int len = clen; 1687 int cl = clen; 1688 const u8 *dp = data; 1689 struct tty_struct *tty; 1690 1691 len = gsm_read_ea_val(&addr, data, cl); 1692 if (len < 1) 1693 return; 1694 1695 addr >>= 1; 1696 /* Closed port, or invalid ? */ 1697 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) 1698 return; 1699 dlci = gsm->dlci[addr]; 1700 1701 /* Must be at least one byte following the EA */ 1702 if ((cl - len) < 1) 1703 return; 1704 1705 dp += len; 1706 cl -= len; 1707 1708 /* get the modem status */ 1709 len = gsm_read_ea_val(&modem, dp, cl); 1710 if (len < 1) 1711 return; 1712 1713 tty = tty_port_tty_get(&dlci->port); 1714 gsm_process_modem(tty, dlci, modem, cl); 1715 if (tty) { 1716 tty_wakeup(tty); 1717 tty_kref_put(tty); 1718 } 1719 gsm_control_reply(gsm, CMD_MSC, data, clen); 1720 } 1721 1722 /** 1723 * gsm_control_negotiation - parameter negotiation received 1724 * @gsm: GSM channel 1725 * @cr: command/response flag 1726 * @data: data following command 1727 * @dlen: data length 1728 * 1729 * We have received a parameter negotiation message. This is used by 1730 * the GSM mux protocol to configure protocol parameters for a new DLCI. 1731 */ 1732 static void gsm_control_negotiation(struct gsm_mux *gsm, unsigned int cr, 1733 const u8 *data, unsigned int dlen) 1734 { 1735 unsigned int addr; 1736 struct gsm_dlci_param_bits pn_reply; 1737 struct gsm_dlci *dlci; 1738 struct gsm_dlci_param_bits *params; 1739 1740 if (dlen < sizeof(struct gsm_dlci_param_bits)) { 1741 gsm->open_error++; 1742 return; 1743 } 1744 1745 /* Invalid DLCI? */ 1746 params = (struct gsm_dlci_param_bits *)data; 1747 addr = FIELD_GET(PN_D_FIELD_DLCI, params->d_bits); 1748 if (addr == 0 || addr >= NUM_DLCI || !gsm->dlci[addr]) { 1749 gsm->open_error++; 1750 return; 1751 } 1752 dlci = gsm->dlci[addr]; 1753 1754 /* Too late for parameter negotiation? */ 1755 if ((!cr && dlci->state == DLCI_OPENING) || dlci->state == DLCI_OPEN) { 1756 gsm->open_error++; 1757 return; 1758 } 1759 1760 /* Process the received parameters */ 1761 if (gsm_process_negotiation(gsm, addr, cr, params) != 0) { 1762 /* Negotiation failed. Close the link. */ 1763 if (debug & DBG_ERRORS) 1764 pr_info("%s PN failed\n", __func__); 1765 gsm->open_error++; 1766 gsm_dlci_close(dlci); 1767 return; 1768 } 1769 1770 if (cr) { 1771 /* Reply command with accepted parameters. */ 1772 if (gsm_encode_params(dlci, &pn_reply) == 0) 1773 gsm_control_reply(gsm, CMD_PN, (const u8 *)&pn_reply, 1774 sizeof(pn_reply)); 1775 else if (debug & DBG_ERRORS) 1776 pr_info("%s PN invalid\n", __func__); 1777 } else if (dlci->state == DLCI_CONFIGURE) { 1778 /* Proceed with link setup by sending SABM before UA */ 1779 dlci->state = DLCI_OPENING; 1780 gsm_command(gsm, dlci->addr, SABM|PF); 1781 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1782 } else { 1783 if (debug & DBG_ERRORS) 1784 pr_info("%s PN in invalid state\n", __func__); 1785 gsm->open_error++; 1786 } 1787 } 1788 1789 /** 1790 * gsm_control_rls - remote line status 1791 * @gsm: GSM channel 1792 * @data: data bytes 1793 * @clen: data length 1794 * 1795 * The modem sends us a two byte message on the control channel whenever 1796 * it wishes to send us an error state from the virtual link. Stuff 1797 * this into the uplink tty if present 1798 */ 1799 1800 static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen) 1801 { 1802 struct tty_port *port; 1803 unsigned int addr = 0; 1804 u8 bits; 1805 int len = clen; 1806 const u8 *dp = data; 1807 1808 while (gsm_read_ea(&addr, *dp++) == 0) { 1809 len--; 1810 if (len == 0) 1811 return; 1812 } 1813 /* Must be at least one byte following ea */ 1814 len--; 1815 if (len <= 0) 1816 return; 1817 addr >>= 1; 1818 /* Closed port, or invalid ? */ 1819 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) 1820 return; 1821 /* No error ? */ 1822 bits = *dp; 1823 if ((bits & 1) == 0) 1824 return; 1825 1826 port = &gsm->dlci[addr]->port; 1827 1828 if (bits & 2) 1829 tty_insert_flip_char(port, 0, TTY_OVERRUN); 1830 if (bits & 4) 1831 tty_insert_flip_char(port, 0, TTY_PARITY); 1832 if (bits & 8) 1833 tty_insert_flip_char(port, 0, TTY_FRAME); 1834 1835 tty_flip_buffer_push(port); 1836 1837 gsm_control_reply(gsm, CMD_RLS, data, clen); 1838 } 1839 1840 static void gsm_dlci_begin_close(struct gsm_dlci *dlci); 1841 1842 /** 1843 * gsm_control_message - DLCI 0 control processing 1844 * @gsm: our GSM mux 1845 * @command: the command EA 1846 * @data: data beyond the command/length EAs 1847 * @clen: length 1848 * 1849 * Input processor for control messages from the other end of the link. 1850 * Processes the incoming request and queues a response frame or an 1851 * NSC response if not supported 1852 */ 1853 1854 static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, 1855 const u8 *data, int clen) 1856 { 1857 u8 buf[1]; 1858 1859 switch (command) { 1860 case CMD_CLD: { 1861 struct gsm_dlci *dlci = gsm->dlci[0]; 1862 /* Modem wishes to close down */ 1863 if (dlci) { 1864 dlci->dead = true; 1865 gsm->dead = true; 1866 gsm_dlci_begin_close(dlci); 1867 } 1868 } 1869 break; 1870 case CMD_TEST: 1871 /* Modem wishes to test, reply with the data */ 1872 gsm_control_reply(gsm, CMD_TEST, data, clen); 1873 break; 1874 case CMD_FCON: 1875 /* Modem can accept data again */ 1876 gsm->constipated = false; 1877 gsm_control_reply(gsm, CMD_FCON, NULL, 0); 1878 /* Kick the link in case it is idling */ 1879 gsmld_write_trigger(gsm); 1880 break; 1881 case CMD_FCOFF: 1882 /* Modem wants us to STFU */ 1883 gsm->constipated = true; 1884 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0); 1885 break; 1886 case CMD_MSC: 1887 /* Out of band modem line change indicator for a DLCI */ 1888 gsm_control_modem(gsm, data, clen); 1889 break; 1890 case CMD_RLS: 1891 /* Out of band error reception for a DLCI */ 1892 gsm_control_rls(gsm, data, clen); 1893 break; 1894 case CMD_PSC: 1895 /* Modem wishes to enter power saving state */ 1896 gsm_control_reply(gsm, CMD_PSC, NULL, 0); 1897 break; 1898 /* Optional commands */ 1899 case CMD_PN: 1900 /* Modem sends a parameter negotiation command */ 1901 gsm_control_negotiation(gsm, 1, data, clen); 1902 break; 1903 /* Optional unsupported commands */ 1904 case CMD_RPN: /* Remote port negotiation */ 1905 case CMD_SNC: /* Service negotiation command */ 1906 gsm->unsupported++; 1907 fallthrough; 1908 default: 1909 /* Reply to bad commands with an NSC */ 1910 buf[0] = command; 1911 gsm_control_reply(gsm, CMD_NSC, buf, 1); 1912 break; 1913 } 1914 } 1915 1916 /** 1917 * gsm_control_response - process a response to our control 1918 * @gsm: our GSM mux 1919 * @command: the command (response) EA 1920 * @data: data beyond the command/length EA 1921 * @clen: length 1922 * 1923 * Process a response to an outstanding command. We only allow a single 1924 * control message in flight so this is fairly easy. All the clean up 1925 * is done by the caller, we just update the fields, flag it as done 1926 * and return 1927 */ 1928 1929 static void gsm_control_response(struct gsm_mux *gsm, unsigned int command, 1930 const u8 *data, int clen) 1931 { 1932 struct gsm_control *ctrl; 1933 struct gsm_dlci *dlci; 1934 unsigned long flags; 1935 1936 spin_lock_irqsave(&gsm->control_lock, flags); 1937 1938 ctrl = gsm->pending_cmd; 1939 dlci = gsm->dlci[0]; 1940 command |= 1; 1941 /* Does the reply match our command */ 1942 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) { 1943 /* Our command was replied to, kill the retry timer */ 1944 del_timer(&gsm->t2_timer); 1945 gsm->pending_cmd = NULL; 1946 /* Rejected by the other end */ 1947 if (command == CMD_NSC) 1948 ctrl->error = -EOPNOTSUPP; 1949 ctrl->done = 1; 1950 wake_up(&gsm->event); 1951 /* Or did we receive the PN response to our PN command */ 1952 } else if (command == CMD_PN) { 1953 gsm_control_negotiation(gsm, 0, data, clen); 1954 /* Or did we receive the TEST response to our TEST command */ 1955 } else if (command == CMD_TEST && clen == 1 && *data == gsm->ka_num) { 1956 gsm->ka_retries = -1; /* trigger new keep-alive message */ 1957 if (dlci && !dlci->dead) 1958 mod_timer(&gsm->ka_timer, jiffies + gsm->keep_alive * HZ / 100); 1959 } 1960 spin_unlock_irqrestore(&gsm->control_lock, flags); 1961 } 1962 1963 /** 1964 * gsm_control_keep_alive - check timeout or start keep-alive 1965 * @t: timer contained in our gsm object 1966 * 1967 * Called off the keep-alive timer expiry signaling that our link 1968 * partner is not responding anymore. Link will be closed. 1969 * This is also called to startup our timer. 1970 */ 1971 1972 static void gsm_control_keep_alive(struct timer_list *t) 1973 { 1974 struct gsm_mux *gsm = from_timer(gsm, t, ka_timer); 1975 unsigned long flags; 1976 1977 spin_lock_irqsave(&gsm->control_lock, flags); 1978 if (gsm->ka_num && gsm->ka_retries == 0) { 1979 /* Keep-alive expired -> close the link */ 1980 if (debug & DBG_ERRORS) 1981 pr_debug("%s keep-alive timed out\n", __func__); 1982 spin_unlock_irqrestore(&gsm->control_lock, flags); 1983 if (gsm->dlci[0]) 1984 gsm_dlci_begin_close(gsm->dlci[0]); 1985 return; 1986 } else if (gsm->keep_alive && gsm->dlci[0] && !gsm->dlci[0]->dead) { 1987 if (gsm->ka_retries > 0) { 1988 /* T2 expired for keep-alive -> resend */ 1989 gsm->ka_retries--; 1990 } else { 1991 /* Start keep-alive timer */ 1992 gsm->ka_num++; 1993 if (!gsm->ka_num) 1994 gsm->ka_num++; 1995 gsm->ka_retries = (signed int)gsm->n2; 1996 } 1997 gsm_control_command(gsm, CMD_TEST, &gsm->ka_num, 1998 sizeof(gsm->ka_num)); 1999 mod_timer(&gsm->ka_timer, 2000 jiffies + gsm->t2 * HZ / 100); 2001 } 2002 spin_unlock_irqrestore(&gsm->control_lock, flags); 2003 } 2004 2005 /** 2006 * gsm_control_transmit - send control packet 2007 * @gsm: gsm mux 2008 * @ctrl: frame to send 2009 * 2010 * Send out a pending control command (called under control lock) 2011 */ 2012 2013 static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl) 2014 { 2015 gsm_control_command(gsm, ctrl->cmd, ctrl->data, ctrl->len); 2016 } 2017 2018 /** 2019 * gsm_control_retransmit - retransmit a control frame 2020 * @t: timer contained in our gsm object 2021 * 2022 * Called off the T2 timer expiry in order to retransmit control frames 2023 * that have been lost in the system somewhere. The control_lock protects 2024 * us from colliding with another sender or a receive completion event. 2025 * In that situation the timer may still occur in a small window but 2026 * gsm->pending_cmd will be NULL and we just let the timer expire. 2027 */ 2028 2029 static void gsm_control_retransmit(struct timer_list *t) 2030 { 2031 struct gsm_mux *gsm = from_timer(gsm, t, t2_timer); 2032 struct gsm_control *ctrl; 2033 unsigned long flags; 2034 spin_lock_irqsave(&gsm->control_lock, flags); 2035 ctrl = gsm->pending_cmd; 2036 if (ctrl) { 2037 if (gsm->cretries == 0 || !gsm->dlci[0] || gsm->dlci[0]->dead) { 2038 gsm->pending_cmd = NULL; 2039 ctrl->error = -ETIMEDOUT; 2040 ctrl->done = 1; 2041 spin_unlock_irqrestore(&gsm->control_lock, flags); 2042 wake_up(&gsm->event); 2043 return; 2044 } 2045 gsm->cretries--; 2046 gsm_control_transmit(gsm, ctrl); 2047 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); 2048 } 2049 spin_unlock_irqrestore(&gsm->control_lock, flags); 2050 } 2051 2052 /** 2053 * gsm_control_send - send a control frame on DLCI 0 2054 * @gsm: the GSM channel 2055 * @command: command to send including CR bit 2056 * @data: bytes of data (must be kmalloced) 2057 * @clen: length of the block to send 2058 * 2059 * Queue and dispatch a control command. Only one command can be 2060 * active at a time. In theory more can be outstanding but the matching 2061 * gets really complicated so for now stick to one outstanding. 2062 */ 2063 2064 static struct gsm_control *gsm_control_send(struct gsm_mux *gsm, 2065 unsigned int command, u8 *data, int clen) 2066 { 2067 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control), 2068 GFP_ATOMIC); 2069 unsigned long flags; 2070 if (ctrl == NULL) 2071 return NULL; 2072 retry: 2073 wait_event(gsm->event, gsm->pending_cmd == NULL); 2074 spin_lock_irqsave(&gsm->control_lock, flags); 2075 if (gsm->pending_cmd != NULL) { 2076 spin_unlock_irqrestore(&gsm->control_lock, flags); 2077 goto retry; 2078 } 2079 ctrl->cmd = command; 2080 ctrl->data = data; 2081 ctrl->len = clen; 2082 gsm->pending_cmd = ctrl; 2083 2084 /* If DLCI0 is in ADM mode skip retries, it won't respond */ 2085 if (gsm->dlci[0]->mode == DLCI_MODE_ADM) 2086 gsm->cretries = 0; 2087 else 2088 gsm->cretries = gsm->n2; 2089 2090 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); 2091 gsm_control_transmit(gsm, ctrl); 2092 spin_unlock_irqrestore(&gsm->control_lock, flags); 2093 return ctrl; 2094 } 2095 2096 /** 2097 * gsm_control_wait - wait for a control to finish 2098 * @gsm: GSM mux 2099 * @control: control we are waiting on 2100 * 2101 * Waits for the control to complete or time out. Frees any used 2102 * resources and returns 0 for success, or an error if the remote 2103 * rejected or ignored the request. 2104 */ 2105 2106 static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control) 2107 { 2108 int err; 2109 wait_event(gsm->event, control->done == 1); 2110 err = control->error; 2111 kfree(control); 2112 return err; 2113 } 2114 2115 2116 /* 2117 * DLCI level handling: Needs krefs 2118 */ 2119 2120 /* 2121 * State transitions and timers 2122 */ 2123 2124 /** 2125 * gsm_dlci_close - a DLCI has closed 2126 * @dlci: DLCI that closed 2127 * 2128 * Perform processing when moving a DLCI into closed state. If there 2129 * is an attached tty this is hung up 2130 */ 2131 2132 static void gsm_dlci_close(struct gsm_dlci *dlci) 2133 { 2134 del_timer(&dlci->t1); 2135 if (debug & DBG_ERRORS) 2136 pr_debug("DLCI %d goes closed.\n", dlci->addr); 2137 dlci->state = DLCI_CLOSED; 2138 /* Prevent us from sending data before the link is up again */ 2139 dlci->constipated = true; 2140 if (dlci->addr != 0) { 2141 tty_port_tty_hangup(&dlci->port, false); 2142 gsm_dlci_clear_queues(dlci->gsm, dlci); 2143 /* Ensure that gsmtty_open() can return. */ 2144 tty_port_set_initialized(&dlci->port, false); 2145 wake_up_interruptible(&dlci->port.open_wait); 2146 } else { 2147 del_timer(&dlci->gsm->ka_timer); 2148 dlci->gsm->dead = true; 2149 } 2150 /* A DLCI 0 close is a MUX termination so we need to kick that 2151 back to userspace somehow */ 2152 gsm_dlci_data_kick(dlci); 2153 wake_up_all(&dlci->gsm->event); 2154 } 2155 2156 /** 2157 * gsm_dlci_open - a DLCI has opened 2158 * @dlci: DLCI that opened 2159 * 2160 * Perform processing when moving a DLCI into open state. 2161 */ 2162 2163 static void gsm_dlci_open(struct gsm_dlci *dlci) 2164 { 2165 struct gsm_mux *gsm = dlci->gsm; 2166 2167 /* Note that SABM UA .. SABM UA first UA lost can mean that we go 2168 open -> open */ 2169 del_timer(&dlci->t1); 2170 /* This will let a tty open continue */ 2171 dlci->state = DLCI_OPEN; 2172 dlci->constipated = false; 2173 if (debug & DBG_ERRORS) 2174 pr_debug("DLCI %d goes open.\n", dlci->addr); 2175 /* Send current modem state */ 2176 if (dlci->addr) { 2177 gsm_modem_update(dlci, 0); 2178 } else { 2179 /* Start keep-alive control */ 2180 gsm->ka_num = 0; 2181 gsm->ka_retries = -1; 2182 mod_timer(&gsm->ka_timer, 2183 jiffies + gsm->keep_alive * HZ / 100); 2184 } 2185 gsm_dlci_data_kick(dlci); 2186 wake_up(&dlci->gsm->event); 2187 } 2188 2189 /** 2190 * gsm_dlci_negotiate - start parameter negotiation 2191 * @dlci: DLCI to open 2192 * 2193 * Starts the parameter negotiation for the new DLCI. This needs to be done 2194 * before the DLCI initialized the channel via SABM. 2195 */ 2196 static int gsm_dlci_negotiate(struct gsm_dlci *dlci) 2197 { 2198 struct gsm_mux *gsm = dlci->gsm; 2199 struct gsm_dlci_param_bits params; 2200 int ret; 2201 2202 ret = gsm_encode_params(dlci, ¶ms); 2203 if (ret != 0) 2204 return ret; 2205 2206 /* We cannot asynchronous wait for the command response with 2207 * gsm_command() and gsm_control_wait() at this point. 2208 */ 2209 ret = gsm_control_command(gsm, CMD_PN, (const u8 *)¶ms, 2210 sizeof(params)); 2211 2212 return ret; 2213 } 2214 2215 /** 2216 * gsm_dlci_t1 - T1 timer expiry 2217 * @t: timer contained in the DLCI that opened 2218 * 2219 * The T1 timer handles retransmits of control frames (essentially of 2220 * SABM and DISC). We resend the command until the retry count runs out 2221 * in which case an opening port goes back to closed and a closing port 2222 * is simply put into closed state (any further frames from the other 2223 * end will get a DM response) 2224 * 2225 * Some control dlci can stay in ADM mode with other dlci working just 2226 * fine. In that case we can just keep the control dlci open after the 2227 * DLCI_OPENING retries time out. 2228 */ 2229 2230 static void gsm_dlci_t1(struct timer_list *t) 2231 { 2232 struct gsm_dlci *dlci = from_timer(dlci, t, t1); 2233 struct gsm_mux *gsm = dlci->gsm; 2234 2235 switch (dlci->state) { 2236 case DLCI_CONFIGURE: 2237 if (dlci->retries && gsm_dlci_negotiate(dlci) == 0) { 2238 dlci->retries--; 2239 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 2240 } else { 2241 gsm->open_error++; 2242 gsm_dlci_begin_close(dlci); /* prevent half open link */ 2243 } 2244 break; 2245 case DLCI_OPENING: 2246 if (dlci->retries) { 2247 dlci->retries--; 2248 gsm_command(dlci->gsm, dlci->addr, SABM|PF); 2249 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 2250 } else if (!dlci->addr && gsm->control == (DM | PF)) { 2251 if (debug & DBG_ERRORS) 2252 pr_info("DLCI %d opening in ADM mode.\n", 2253 dlci->addr); 2254 dlci->mode = DLCI_MODE_ADM; 2255 gsm_dlci_open(dlci); 2256 } else { 2257 gsm->open_error++; 2258 gsm_dlci_begin_close(dlci); /* prevent half open link */ 2259 } 2260 2261 break; 2262 case DLCI_CLOSING: 2263 if (dlci->retries) { 2264 dlci->retries--; 2265 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 2266 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 2267 } else 2268 gsm_dlci_close(dlci); 2269 break; 2270 default: 2271 pr_debug("%s: unhandled state: %d\n", __func__, dlci->state); 2272 break; 2273 } 2274 } 2275 2276 /** 2277 * gsm_dlci_begin_open - start channel open procedure 2278 * @dlci: DLCI to open 2279 * 2280 * Commence opening a DLCI from the Linux side. We issue SABM messages 2281 * to the modem which should then reply with a UA or ADM, at which point 2282 * we will move into open state. Opening is done asynchronously with retry 2283 * running off timers and the responses. 2284 * Parameter negotiation is performed before SABM if required. 2285 */ 2286 2287 static void gsm_dlci_begin_open(struct gsm_dlci *dlci) 2288 { 2289 struct gsm_mux *gsm = dlci ? dlci->gsm : NULL; 2290 bool need_pn = false; 2291 2292 if (!gsm) 2293 return; 2294 2295 if (dlci->addr != 0) { 2296 if (gsm->adaption != 1 || gsm->adaption != dlci->adaption) 2297 need_pn = true; 2298 if (dlci->prio != (roundup(dlci->addr + 1, 8) - 1)) 2299 need_pn = true; 2300 if (gsm->ftype != dlci->ftype) 2301 need_pn = true; 2302 } 2303 2304 switch (dlci->state) { 2305 case DLCI_CLOSED: 2306 case DLCI_WAITING_CONFIG: 2307 case DLCI_CLOSING: 2308 dlci->retries = gsm->n2; 2309 if (!need_pn) { 2310 dlci->state = DLCI_OPENING; 2311 gsm_command(gsm, dlci->addr, SABM|PF); 2312 } else { 2313 /* Configure DLCI before setup */ 2314 dlci->state = DLCI_CONFIGURE; 2315 if (gsm_dlci_negotiate(dlci) != 0) { 2316 gsm_dlci_close(dlci); 2317 return; 2318 } 2319 } 2320 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 2321 break; 2322 default: 2323 break; 2324 } 2325 } 2326 2327 /** 2328 * gsm_dlci_set_opening - change state to opening 2329 * @dlci: DLCI to open 2330 * 2331 * Change internal state to wait for DLCI open from initiator side. 2332 * We set off timers and responses upon reception of an SABM. 2333 */ 2334 static void gsm_dlci_set_opening(struct gsm_dlci *dlci) 2335 { 2336 switch (dlci->state) { 2337 case DLCI_CLOSED: 2338 case DLCI_WAITING_CONFIG: 2339 case DLCI_CLOSING: 2340 dlci->state = DLCI_OPENING; 2341 break; 2342 default: 2343 break; 2344 } 2345 } 2346 2347 /** 2348 * gsm_dlci_set_wait_config - wait for channel configuration 2349 * @dlci: DLCI to configure 2350 * 2351 * Wait for a DLCI configuration from the application. 2352 */ 2353 static void gsm_dlci_set_wait_config(struct gsm_dlci *dlci) 2354 { 2355 switch (dlci->state) { 2356 case DLCI_CLOSED: 2357 case DLCI_CLOSING: 2358 dlci->state = DLCI_WAITING_CONFIG; 2359 break; 2360 default: 2361 break; 2362 } 2363 } 2364 2365 /** 2366 * gsm_dlci_begin_close - start channel open procedure 2367 * @dlci: DLCI to open 2368 * 2369 * Commence closing a DLCI from the Linux side. We issue DISC messages 2370 * to the modem which should then reply with a UA, at which point we 2371 * will move into closed state. Closing is done asynchronously with retry 2372 * off timers. We may also receive a DM reply from the other end which 2373 * indicates the channel was already closed. 2374 */ 2375 2376 static void gsm_dlci_begin_close(struct gsm_dlci *dlci) 2377 { 2378 struct gsm_mux *gsm = dlci->gsm; 2379 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING) 2380 return; 2381 dlci->retries = gsm->n2; 2382 dlci->state = DLCI_CLOSING; 2383 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 2384 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 2385 wake_up_interruptible(&gsm->event); 2386 } 2387 2388 /** 2389 * gsm_dlci_data - data arrived 2390 * @dlci: channel 2391 * @data: block of bytes received 2392 * @clen: length of received block 2393 * 2394 * A UI or UIH frame has arrived which contains data for a channel 2395 * other than the control channel. If the relevant virtual tty is 2396 * open we shovel the bits down it, if not we drop them. 2397 */ 2398 2399 static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen) 2400 { 2401 /* krefs .. */ 2402 struct tty_port *port = &dlci->port; 2403 struct tty_struct *tty; 2404 unsigned int modem = 0; 2405 int len; 2406 2407 if (debug & DBG_TTY) 2408 pr_debug("%d bytes for tty\n", clen); 2409 switch (dlci->adaption) { 2410 /* Unsupported types */ 2411 case 4: /* Packetised interruptible data */ 2412 break; 2413 case 3: /* Packetised uininterruptible voice/data */ 2414 break; 2415 case 2: /* Asynchronous serial with line state in each frame */ 2416 len = gsm_read_ea_val(&modem, data, clen); 2417 if (len < 1) 2418 return; 2419 tty = tty_port_tty_get(port); 2420 if (tty) { 2421 gsm_process_modem(tty, dlci, modem, len); 2422 tty_wakeup(tty); 2423 tty_kref_put(tty); 2424 } 2425 /* Skip processed modem data */ 2426 data += len; 2427 clen -= len; 2428 fallthrough; 2429 case 1: /* Line state will go via DLCI 0 controls only */ 2430 default: 2431 tty_insert_flip_string(port, data, clen); 2432 tty_flip_buffer_push(port); 2433 } 2434 } 2435 2436 /** 2437 * gsm_dlci_command - data arrived on control channel 2438 * @dlci: channel 2439 * @data: block of bytes received 2440 * @len: length of received block 2441 * 2442 * A UI or UIH frame has arrived which contains data for DLCI 0 the 2443 * control channel. This should contain a command EA followed by 2444 * control data bytes. The command EA contains a command/response bit 2445 * and we divide up the work accordingly. 2446 */ 2447 2448 static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len) 2449 { 2450 /* See what command is involved */ 2451 unsigned int command = 0; 2452 unsigned int clen = 0; 2453 unsigned int dlen; 2454 2455 /* read the command */ 2456 dlen = gsm_read_ea_val(&command, data, len); 2457 len -= dlen; 2458 data += dlen; 2459 2460 /* read any control data */ 2461 dlen = gsm_read_ea_val(&clen, data, len); 2462 len -= dlen; 2463 data += dlen; 2464 2465 /* Malformed command? */ 2466 if (clen > len) { 2467 dlci->gsm->malformed++; 2468 return; 2469 } 2470 2471 if (command & 1) 2472 gsm_control_message(dlci->gsm, command, data, clen); 2473 else 2474 gsm_control_response(dlci->gsm, command, data, clen); 2475 } 2476 2477 /** 2478 * gsm_kick_timer - transmit if possible 2479 * @t: timer contained in our gsm object 2480 * 2481 * Transmit data from DLCIs if the queue is empty. We can't rely on 2482 * a tty wakeup except when we filled the pipe so we need to fire off 2483 * new data ourselves in other cases. 2484 */ 2485 static void gsm_kick_timer(struct timer_list *t) 2486 { 2487 struct gsm_mux *gsm = from_timer(gsm, t, kick_timer); 2488 unsigned long flags; 2489 int sent = 0; 2490 2491 spin_lock_irqsave(&gsm->tx_lock, flags); 2492 /* If we have nothing running then we need to fire up */ 2493 if (gsm->tx_bytes < TX_THRESH_LO) 2494 sent = gsm_dlci_data_sweep(gsm); 2495 spin_unlock_irqrestore(&gsm->tx_lock, flags); 2496 2497 if (sent && debug & DBG_DATA) 2498 pr_info("%s TX queue stalled\n", __func__); 2499 } 2500 2501 /** 2502 * gsm_dlci_copy_config_values - copy DLCI configuration 2503 * @dlci: source DLCI 2504 * @dc: configuration structure to fill 2505 */ 2506 static void gsm_dlci_copy_config_values(struct gsm_dlci *dlci, struct gsm_dlci_config *dc) 2507 { 2508 memset(dc, 0, sizeof(*dc)); 2509 dc->channel = (u32)dlci->addr; 2510 dc->adaption = (u32)dlci->adaption; 2511 dc->mtu = (u32)dlci->mtu; 2512 dc->priority = (u32)dlci->prio; 2513 if (dlci->ftype == UIH) 2514 dc->i = 1; 2515 else 2516 dc->i = 2; 2517 dc->k = (u32)dlci->k; 2518 } 2519 2520 /** 2521 * gsm_dlci_config - configure DLCI from configuration 2522 * @dlci: DLCI to configure 2523 * @dc: DLCI configuration 2524 * @open: open DLCI after configuration? 2525 */ 2526 static int gsm_dlci_config(struct gsm_dlci *dlci, struct gsm_dlci_config *dc, int open) 2527 { 2528 struct gsm_mux *gsm; 2529 bool need_restart = false; 2530 bool need_open = false; 2531 unsigned int i; 2532 2533 /* 2534 * Check that userspace doesn't put stuff in here to prevent breakages 2535 * in the future. 2536 */ 2537 for (i = 0; i < ARRAY_SIZE(dc->reserved); i++) 2538 if (dc->reserved[i]) 2539 return -EINVAL; 2540 2541 if (!dlci) 2542 return -EINVAL; 2543 gsm = dlci->gsm; 2544 2545 /* Stuff we don't support yet - I frame transport */ 2546 if (dc->adaption != 1 && dc->adaption != 2) 2547 return -EOPNOTSUPP; 2548 if (dc->mtu > MAX_MTU || dc->mtu < MIN_MTU || dc->mtu > gsm->mru) 2549 return -EINVAL; 2550 if (dc->priority >= 64) 2551 return -EINVAL; 2552 if (dc->i == 0 || dc->i > 2) /* UIH and UI only */ 2553 return -EINVAL; 2554 if (dc->k > 7) 2555 return -EINVAL; 2556 if (dc->flags & ~GSM_FL_RESTART) /* allow future extensions */ 2557 return -EINVAL; 2558 2559 /* 2560 * See what is needed for reconfiguration 2561 */ 2562 /* Framing fields */ 2563 if (dc->adaption != dlci->adaption) 2564 need_restart = true; 2565 if (dc->mtu != dlci->mtu) 2566 need_restart = true; 2567 if (dc->i != dlci->ftype) 2568 need_restart = true; 2569 /* Requires care */ 2570 if (dc->priority != dlci->prio) 2571 need_restart = true; 2572 if (dc->flags & GSM_FL_RESTART) 2573 need_restart = true; 2574 2575 if ((open && gsm->wait_config) || need_restart) 2576 need_open = true; 2577 if (dlci->state == DLCI_WAITING_CONFIG) { 2578 need_restart = false; 2579 need_open = true; 2580 } 2581 2582 /* 2583 * Close down what is needed, restart and initiate the new 2584 * configuration. 2585 */ 2586 if (need_restart) { 2587 gsm_dlci_begin_close(dlci); 2588 wait_event_interruptible(gsm->event, dlci->state == DLCI_CLOSED); 2589 if (signal_pending(current)) 2590 return -EINTR; 2591 } 2592 /* 2593 * Setup the new configuration values 2594 */ 2595 dlci->adaption = (int)dc->adaption; 2596 2597 if (dc->mtu) 2598 dlci->mtu = (unsigned int)dc->mtu; 2599 else 2600 dlci->mtu = gsm->mtu; 2601 2602 if (dc->priority) 2603 dlci->prio = (u8)dc->priority; 2604 else 2605 dlci->prio = roundup(dlci->addr + 1, 8) - 1; 2606 2607 if (dc->i == 1) 2608 dlci->ftype = UIH; 2609 else if (dc->i == 2) 2610 dlci->ftype = UI; 2611 2612 if (dc->k) 2613 dlci->k = (u8)dc->k; 2614 else 2615 dlci->k = gsm->k; 2616 2617 if (need_open) { 2618 if (gsm->initiator) 2619 gsm_dlci_begin_open(dlci); 2620 else 2621 gsm_dlci_set_opening(dlci); 2622 } 2623 2624 return 0; 2625 } 2626 2627 /* 2628 * Allocate/Free DLCI channels 2629 */ 2630 2631 /** 2632 * gsm_dlci_alloc - allocate a DLCI 2633 * @gsm: GSM mux 2634 * @addr: address of the DLCI 2635 * 2636 * Allocate and install a new DLCI object into the GSM mux. 2637 * 2638 * FIXME: review locking races 2639 */ 2640 2641 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr) 2642 { 2643 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC); 2644 if (dlci == NULL) 2645 return NULL; 2646 spin_lock_init(&dlci->lock); 2647 mutex_init(&dlci->mutex); 2648 if (kfifo_alloc(&dlci->fifo, TX_SIZE, GFP_KERNEL) < 0) { 2649 kfree(dlci); 2650 return NULL; 2651 } 2652 2653 skb_queue_head_init(&dlci->skb_list); 2654 timer_setup(&dlci->t1, gsm_dlci_t1, 0); 2655 tty_port_init(&dlci->port); 2656 dlci->port.ops = &gsm_port_ops; 2657 dlci->gsm = gsm; 2658 dlci->addr = addr; 2659 dlci->adaption = gsm->adaption; 2660 dlci->mtu = gsm->mtu; 2661 if (addr == 0) 2662 dlci->prio = 0; 2663 else 2664 dlci->prio = roundup(addr + 1, 8) - 1; 2665 dlci->ftype = gsm->ftype; 2666 dlci->k = gsm->k; 2667 dlci->state = DLCI_CLOSED; 2668 if (addr) { 2669 dlci->data = gsm_dlci_data; 2670 /* Prevent us from sending data before the link is up */ 2671 dlci->constipated = true; 2672 } else { 2673 dlci->data = gsm_dlci_command; 2674 } 2675 gsm->dlci[addr] = dlci; 2676 return dlci; 2677 } 2678 2679 /** 2680 * gsm_dlci_free - free DLCI 2681 * @port: tty port for DLCI to free 2682 * 2683 * Free up a DLCI. 2684 * 2685 * Can sleep. 2686 */ 2687 static void gsm_dlci_free(struct tty_port *port) 2688 { 2689 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2690 2691 timer_shutdown_sync(&dlci->t1); 2692 dlci->gsm->dlci[dlci->addr] = NULL; 2693 kfifo_free(&dlci->fifo); 2694 while ((dlci->skb = skb_dequeue(&dlci->skb_list))) 2695 dev_kfree_skb(dlci->skb); 2696 kfree(dlci); 2697 } 2698 2699 static inline void dlci_get(struct gsm_dlci *dlci) 2700 { 2701 tty_port_get(&dlci->port); 2702 } 2703 2704 static inline void dlci_put(struct gsm_dlci *dlci) 2705 { 2706 tty_port_put(&dlci->port); 2707 } 2708 2709 static void gsm_destroy_network(struct gsm_dlci *dlci); 2710 2711 /** 2712 * gsm_dlci_release - release DLCI 2713 * @dlci: DLCI to destroy 2714 * 2715 * Release a DLCI. Actual free is deferred until either 2716 * mux is closed or tty is closed - whichever is last. 2717 * 2718 * Can sleep. 2719 */ 2720 static void gsm_dlci_release(struct gsm_dlci *dlci) 2721 { 2722 struct tty_struct *tty = tty_port_tty_get(&dlci->port); 2723 if (tty) { 2724 mutex_lock(&dlci->mutex); 2725 gsm_destroy_network(dlci); 2726 mutex_unlock(&dlci->mutex); 2727 2728 /* We cannot use tty_hangup() because in tty_kref_put() the tty 2729 * driver assumes that the hangup queue is free and reuses it to 2730 * queue release_one_tty() -> NULL pointer panic in 2731 * process_one_work(). 2732 */ 2733 tty_vhangup(tty); 2734 2735 tty_port_tty_set(&dlci->port, NULL); 2736 tty_kref_put(tty); 2737 } 2738 dlci->state = DLCI_CLOSED; 2739 dlci_put(dlci); 2740 } 2741 2742 /* 2743 * LAPBish link layer logic 2744 */ 2745 2746 /** 2747 * gsm_queue - a GSM frame is ready to process 2748 * @gsm: pointer to our gsm mux 2749 * 2750 * At this point in time a frame has arrived and been demangled from 2751 * the line encoding. All the differences between the encodings have 2752 * been handled below us and the frame is unpacked into the structures. 2753 * The fcs holds the header FCS but any data FCS must be added here. 2754 */ 2755 2756 static void gsm_queue(struct gsm_mux *gsm) 2757 { 2758 struct gsm_dlci *dlci; 2759 u8 cr; 2760 int address; 2761 2762 if (gsm->fcs != GOOD_FCS) { 2763 gsm->bad_fcs++; 2764 if (debug & DBG_DATA) 2765 pr_debug("BAD FCS %02x\n", gsm->fcs); 2766 return; 2767 } 2768 address = gsm->address >> 1; 2769 if (address >= NUM_DLCI) 2770 goto invalid; 2771 2772 cr = gsm->address & 1; /* C/R bit */ 2773 cr ^= gsm->initiator ? 0 : 1; /* Flip so 1 always means command */ 2774 2775 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len); 2776 2777 dlci = gsm->dlci[address]; 2778 2779 switch (gsm->control) { 2780 case SABM|PF: 2781 if (cr == 1) { 2782 gsm->open_error++; 2783 goto invalid; 2784 } 2785 if (dlci == NULL) 2786 dlci = gsm_dlci_alloc(gsm, address); 2787 if (dlci == NULL) { 2788 gsm->open_error++; 2789 return; 2790 } 2791 if (dlci->dead) 2792 gsm_response(gsm, address, DM|PF); 2793 else { 2794 gsm_response(gsm, address, UA|PF); 2795 gsm_dlci_open(dlci); 2796 } 2797 break; 2798 case DISC|PF: 2799 if (cr == 1) 2800 goto invalid; 2801 if (dlci == NULL || dlci->state == DLCI_CLOSED) { 2802 gsm_response(gsm, address, DM|PF); 2803 return; 2804 } 2805 /* Real close complete */ 2806 gsm_response(gsm, address, UA|PF); 2807 gsm_dlci_close(dlci); 2808 break; 2809 case UA|PF: 2810 if (cr == 0 || dlci == NULL) 2811 break; 2812 switch (dlci->state) { 2813 case DLCI_CLOSING: 2814 gsm_dlci_close(dlci); 2815 break; 2816 case DLCI_OPENING: 2817 gsm_dlci_open(dlci); 2818 break; 2819 default: 2820 pr_debug("%s: unhandled state: %d\n", __func__, 2821 dlci->state); 2822 break; 2823 } 2824 break; 2825 case DM: /* DM can be valid unsolicited */ 2826 case DM|PF: 2827 if (cr) 2828 goto invalid; 2829 if (dlci == NULL) 2830 return; 2831 gsm_dlci_close(dlci); 2832 break; 2833 case UI: 2834 case UI|PF: 2835 case UIH: 2836 case UIH|PF: 2837 if (dlci == NULL || dlci->state != DLCI_OPEN) { 2838 gsm_response(gsm, address, DM|PF); 2839 return; 2840 } 2841 dlci->data(dlci, gsm->buf, gsm->len); 2842 break; 2843 default: 2844 goto invalid; 2845 } 2846 return; 2847 invalid: 2848 gsm->malformed++; 2849 return; 2850 } 2851 2852 /** 2853 * gsm0_receive_state_check_and_fix - check and correct receive state 2854 * @gsm: gsm data for this ldisc instance 2855 * 2856 * Ensures that the current receive state is valid for basic option mode. 2857 */ 2858 2859 static void gsm0_receive_state_check_and_fix(struct gsm_mux *gsm) 2860 { 2861 switch (gsm->state) { 2862 case GSM_SEARCH: 2863 case GSM0_ADDRESS: 2864 case GSM0_CONTROL: 2865 case GSM0_LEN0: 2866 case GSM0_LEN1: 2867 case GSM0_DATA: 2868 case GSM0_FCS: 2869 case GSM0_SSOF: 2870 break; 2871 default: 2872 gsm->state = GSM_SEARCH; 2873 break; 2874 } 2875 } 2876 2877 /** 2878 * gsm0_receive - perform processing for non-transparency 2879 * @gsm: gsm data for this ldisc instance 2880 * @c: character 2881 * 2882 * Receive bytes in gsm mode 0 2883 */ 2884 2885 static void gsm0_receive(struct gsm_mux *gsm, u8 c) 2886 { 2887 unsigned int len; 2888 2889 gsm0_receive_state_check_and_fix(gsm); 2890 switch (gsm->state) { 2891 case GSM_SEARCH: /* SOF marker */ 2892 if (c == GSM0_SOF) { 2893 gsm->state = GSM0_ADDRESS; 2894 gsm->address = 0; 2895 gsm->len = 0; 2896 gsm->fcs = INIT_FCS; 2897 } 2898 break; 2899 case GSM0_ADDRESS: /* Address EA */ 2900 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 2901 if (gsm_read_ea(&gsm->address, c)) 2902 gsm->state = GSM0_CONTROL; 2903 break; 2904 case GSM0_CONTROL: /* Control Byte */ 2905 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 2906 gsm->control = c; 2907 gsm->state = GSM0_LEN0; 2908 break; 2909 case GSM0_LEN0: /* Length EA */ 2910 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 2911 if (gsm_read_ea(&gsm->len, c)) { 2912 if (gsm->len > gsm->mru) { 2913 gsm->bad_size++; 2914 gsm->state = GSM_SEARCH; 2915 break; 2916 } 2917 gsm->count = 0; 2918 if (!gsm->len) 2919 gsm->state = GSM0_FCS; 2920 else 2921 gsm->state = GSM0_DATA; 2922 break; 2923 } 2924 gsm->state = GSM0_LEN1; 2925 break; 2926 case GSM0_LEN1: 2927 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 2928 len = c; 2929 gsm->len |= len << 7; 2930 if (gsm->len > gsm->mru) { 2931 gsm->bad_size++; 2932 gsm->state = GSM_SEARCH; 2933 break; 2934 } 2935 gsm->count = 0; 2936 if (!gsm->len) 2937 gsm->state = GSM0_FCS; 2938 else 2939 gsm->state = GSM0_DATA; 2940 break; 2941 case GSM0_DATA: /* Data */ 2942 gsm->buf[gsm->count++] = c; 2943 if (gsm->count >= MAX_MRU) { 2944 gsm->bad_size++; 2945 gsm->state = GSM_SEARCH; 2946 } else if (gsm->count >= gsm->len) { 2947 /* Calculate final FCS for UI frames over all data */ 2948 if ((gsm->control & ~PF) != UIH) { 2949 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, 2950 gsm->count); 2951 } 2952 gsm->state = GSM0_FCS; 2953 } 2954 break; 2955 case GSM0_FCS: /* FCS follows the packet */ 2956 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 2957 gsm->state = GSM0_SSOF; 2958 break; 2959 case GSM0_SSOF: 2960 gsm->state = GSM_SEARCH; 2961 if (c == GSM0_SOF) 2962 gsm_queue(gsm); 2963 else 2964 gsm->bad_size++; 2965 break; 2966 default: 2967 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state); 2968 break; 2969 } 2970 } 2971 2972 /** 2973 * gsm1_receive_state_check_and_fix - check and correct receive state 2974 * @gsm: gsm data for this ldisc instance 2975 * 2976 * Ensures that the current receive state is valid for advanced option mode. 2977 */ 2978 2979 static void gsm1_receive_state_check_and_fix(struct gsm_mux *gsm) 2980 { 2981 switch (gsm->state) { 2982 case GSM_SEARCH: 2983 case GSM1_START: 2984 case GSM1_ADDRESS: 2985 case GSM1_CONTROL: 2986 case GSM1_DATA: 2987 case GSM1_OVERRUN: 2988 break; 2989 default: 2990 gsm->state = GSM_SEARCH; 2991 break; 2992 } 2993 } 2994 2995 /** 2996 * gsm1_receive - perform processing for non-transparency 2997 * @gsm: gsm data for this ldisc instance 2998 * @c: character 2999 * 3000 * Receive bytes in mode 1 (Advanced option) 3001 */ 3002 3003 static void gsm1_receive(struct gsm_mux *gsm, u8 c) 3004 { 3005 gsm1_receive_state_check_and_fix(gsm); 3006 /* handle XON/XOFF */ 3007 if ((c & ISO_IEC_646_MASK) == XON) { 3008 gsm->constipated = true; 3009 return; 3010 } else if ((c & ISO_IEC_646_MASK) == XOFF) { 3011 gsm->constipated = false; 3012 /* Kick the link in case it is idling */ 3013 gsmld_write_trigger(gsm); 3014 return; 3015 } 3016 if (c == GSM1_SOF) { 3017 /* EOF is only valid in frame if we have got to the data state */ 3018 if (gsm->state == GSM1_DATA) { 3019 if (gsm->count < 1) { 3020 /* Missing FSC */ 3021 gsm->malformed++; 3022 gsm->state = GSM1_START; 3023 return; 3024 } 3025 /* Remove the FCS from data */ 3026 gsm->count--; 3027 if ((gsm->control & ~PF) != UIH) { 3028 /* Calculate final FCS for UI frames over all 3029 * data but FCS 3030 */ 3031 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, 3032 gsm->count); 3033 } 3034 /* Add the FCS itself to test against GOOD_FCS */ 3035 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]); 3036 gsm->len = gsm->count; 3037 gsm_queue(gsm); 3038 gsm->state = GSM1_START; 3039 return; 3040 } 3041 /* Any partial frame was a runt so go back to start */ 3042 if (gsm->state != GSM1_START) { 3043 if (gsm->state != GSM_SEARCH) 3044 gsm->malformed++; 3045 gsm->state = GSM1_START; 3046 } 3047 /* A SOF in GSM_START means we are still reading idling or 3048 framing bytes */ 3049 return; 3050 } 3051 3052 if (c == GSM1_ESCAPE) { 3053 gsm->escape = true; 3054 return; 3055 } 3056 3057 /* Only an unescaped SOF gets us out of GSM search */ 3058 if (gsm->state == GSM_SEARCH) 3059 return; 3060 3061 if (gsm->escape) { 3062 c ^= GSM1_ESCAPE_BITS; 3063 gsm->escape = false; 3064 } 3065 switch (gsm->state) { 3066 case GSM1_START: /* First byte after SOF */ 3067 gsm->address = 0; 3068 gsm->state = GSM1_ADDRESS; 3069 gsm->fcs = INIT_FCS; 3070 fallthrough; 3071 case GSM1_ADDRESS: /* Address continuation */ 3072 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 3073 if (gsm_read_ea(&gsm->address, c)) 3074 gsm->state = GSM1_CONTROL; 3075 break; 3076 case GSM1_CONTROL: /* Control Byte */ 3077 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 3078 gsm->control = c; 3079 gsm->count = 0; 3080 gsm->state = GSM1_DATA; 3081 break; 3082 case GSM1_DATA: /* Data */ 3083 if (gsm->count > gsm->mru || gsm->count > MAX_MRU) { /* Allow one for the FCS */ 3084 gsm->state = GSM1_OVERRUN; 3085 gsm->bad_size++; 3086 } else 3087 gsm->buf[gsm->count++] = c; 3088 break; 3089 case GSM1_OVERRUN: /* Over-long - eg a dropped SOF */ 3090 break; 3091 default: 3092 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state); 3093 break; 3094 } 3095 } 3096 3097 /** 3098 * gsm_error - handle tty error 3099 * @gsm: ldisc data 3100 * 3101 * Handle an error in the receipt of data for a frame. Currently we just 3102 * go back to hunting for a SOF. 3103 * 3104 * FIXME: better diagnostics ? 3105 */ 3106 3107 static void gsm_error(struct gsm_mux *gsm) 3108 { 3109 gsm->state = GSM_SEARCH; 3110 gsm->io_error++; 3111 } 3112 3113 /** 3114 * gsm_cleanup_mux - generic GSM protocol cleanup 3115 * @gsm: our mux 3116 * @disc: disconnect link? 3117 * 3118 * Clean up the bits of the mux which are the same for all framing 3119 * protocols. Remove the mux from the mux table, stop all the timers 3120 * and then shut down each device hanging up the channels as we go. 3121 */ 3122 3123 static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc) 3124 { 3125 int i; 3126 struct gsm_dlci *dlci; 3127 struct gsm_msg *txq, *ntxq; 3128 3129 gsm->dead = true; 3130 mutex_lock(&gsm->mutex); 3131 3132 dlci = gsm->dlci[0]; 3133 if (dlci) { 3134 if (disc && dlci->state != DLCI_CLOSED) { 3135 gsm_dlci_begin_close(dlci); 3136 wait_event(gsm->event, dlci->state == DLCI_CLOSED); 3137 } 3138 dlci->dead = true; 3139 } 3140 3141 /* Finish outstanding timers, making sure they are done */ 3142 del_timer_sync(&gsm->kick_timer); 3143 del_timer_sync(&gsm->t2_timer); 3144 del_timer_sync(&gsm->ka_timer); 3145 3146 /* Finish writing to ldisc */ 3147 flush_work(&gsm->tx_work); 3148 3149 /* Free up any link layer users and finally the control channel */ 3150 if (gsm->has_devices) { 3151 gsm_unregister_devices(gsm_tty_driver, gsm->num); 3152 gsm->has_devices = false; 3153 } 3154 for (i = NUM_DLCI - 1; i >= 0; i--) 3155 if (gsm->dlci[i]) 3156 gsm_dlci_release(gsm->dlci[i]); 3157 mutex_unlock(&gsm->mutex); 3158 /* Now wipe the queues */ 3159 tty_ldisc_flush(gsm->tty); 3160 3161 guard(spinlock_irqsave)(&gsm->tx_lock); 3162 list_for_each_entry_safe(txq, ntxq, &gsm->tx_ctrl_list, list) 3163 kfree(txq); 3164 INIT_LIST_HEAD(&gsm->tx_ctrl_list); 3165 list_for_each_entry_safe(txq, ntxq, &gsm->tx_data_list, list) 3166 kfree(txq); 3167 INIT_LIST_HEAD(&gsm->tx_data_list); 3168 } 3169 3170 /** 3171 * gsm_activate_mux - generic GSM setup 3172 * @gsm: our mux 3173 * 3174 * Set up the bits of the mux which are the same for all framing 3175 * protocols. Add the mux to the mux table so it can be opened and 3176 * finally kick off connecting to DLCI 0 on the modem. 3177 */ 3178 3179 static int gsm_activate_mux(struct gsm_mux *gsm) 3180 { 3181 struct gsm_dlci *dlci; 3182 int ret; 3183 3184 dlci = gsm_dlci_alloc(gsm, 0); 3185 if (dlci == NULL) 3186 return -ENOMEM; 3187 3188 if (gsm->encoding == GSM_BASIC_OPT) 3189 gsm->receive = gsm0_receive; 3190 else 3191 gsm->receive = gsm1_receive; 3192 3193 ret = gsm_register_devices(gsm_tty_driver, gsm->num); 3194 if (ret) 3195 return ret; 3196 3197 gsm->has_devices = true; 3198 gsm->dead = false; /* Tty opens are now permissible */ 3199 return 0; 3200 } 3201 3202 /** 3203 * gsm_free_mux - free up a mux 3204 * @gsm: mux to free 3205 * 3206 * Dispose of allocated resources for a dead mux 3207 */ 3208 static void gsm_free_mux(struct gsm_mux *gsm) 3209 { 3210 int i; 3211 3212 for (i = 0; i < MAX_MUX; i++) { 3213 if (gsm == gsm_mux[i]) { 3214 gsm_mux[i] = NULL; 3215 break; 3216 } 3217 } 3218 mutex_destroy(&gsm->mutex); 3219 kfree(gsm->txframe); 3220 kfree(gsm->buf); 3221 kfree(gsm); 3222 } 3223 3224 /** 3225 * gsm_free_muxr - free up a mux 3226 * @ref: kreference to the mux to free 3227 * 3228 * Dispose of allocated resources for a dead mux 3229 */ 3230 static void gsm_free_muxr(struct kref *ref) 3231 { 3232 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref); 3233 gsm_free_mux(gsm); 3234 } 3235 3236 static inline void mux_get(struct gsm_mux *gsm) 3237 { 3238 unsigned long flags; 3239 3240 spin_lock_irqsave(&gsm_mux_lock, flags); 3241 kref_get(&gsm->ref); 3242 spin_unlock_irqrestore(&gsm_mux_lock, flags); 3243 } 3244 3245 static inline void mux_put(struct gsm_mux *gsm) 3246 { 3247 unsigned long flags; 3248 3249 spin_lock_irqsave(&gsm_mux_lock, flags); 3250 kref_put(&gsm->ref, gsm_free_muxr); 3251 spin_unlock_irqrestore(&gsm_mux_lock, flags); 3252 } 3253 3254 static inline unsigned int mux_num_to_base(struct gsm_mux *gsm) 3255 { 3256 return gsm->num * NUM_DLCI; 3257 } 3258 3259 static inline unsigned int mux_line_to_num(unsigned int line) 3260 { 3261 return line / NUM_DLCI; 3262 } 3263 3264 /** 3265 * gsm_alloc_mux - allocate a mux 3266 * 3267 * Creates a new mux ready for activation. 3268 */ 3269 3270 static struct gsm_mux *gsm_alloc_mux(void) 3271 { 3272 int i; 3273 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL); 3274 if (gsm == NULL) 3275 return NULL; 3276 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL); 3277 if (gsm->buf == NULL) { 3278 kfree(gsm); 3279 return NULL; 3280 } 3281 gsm->txframe = kmalloc(2 * (MAX_MTU + PROT_OVERHEAD - 1), GFP_KERNEL); 3282 if (gsm->txframe == NULL) { 3283 kfree(gsm->buf); 3284 kfree(gsm); 3285 return NULL; 3286 } 3287 spin_lock_init(&gsm->lock); 3288 mutex_init(&gsm->mutex); 3289 kref_init(&gsm->ref); 3290 INIT_LIST_HEAD(&gsm->tx_ctrl_list); 3291 INIT_LIST_HEAD(&gsm->tx_data_list); 3292 timer_setup(&gsm->kick_timer, gsm_kick_timer, 0); 3293 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0); 3294 timer_setup(&gsm->ka_timer, gsm_control_keep_alive, 0); 3295 INIT_WORK(&gsm->tx_work, gsmld_write_task); 3296 init_waitqueue_head(&gsm->event); 3297 spin_lock_init(&gsm->control_lock); 3298 spin_lock_init(&gsm->tx_lock); 3299 3300 gsm->t1 = T1; 3301 gsm->t2 = T2; 3302 gsm->t3 = T3; 3303 gsm->n2 = N2; 3304 gsm->k = K; 3305 gsm->ftype = UIH; 3306 gsm->adaption = 1; 3307 gsm->encoding = GSM_ADV_OPT; 3308 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */ 3309 gsm->mtu = 64; 3310 gsm->dead = true; /* Avoid early tty opens */ 3311 gsm->wait_config = false; /* Disabled */ 3312 gsm->keep_alive = 0; /* Disabled */ 3313 3314 /* Store the instance to the mux array or abort if no space is 3315 * available. 3316 */ 3317 spin_lock(&gsm_mux_lock); 3318 for (i = 0; i < MAX_MUX; i++) { 3319 if (!gsm_mux[i]) { 3320 gsm_mux[i] = gsm; 3321 gsm->num = i; 3322 break; 3323 } 3324 } 3325 spin_unlock(&gsm_mux_lock); 3326 if (i == MAX_MUX) { 3327 mutex_destroy(&gsm->mutex); 3328 kfree(gsm->txframe); 3329 kfree(gsm->buf); 3330 kfree(gsm); 3331 return NULL; 3332 } 3333 3334 return gsm; 3335 } 3336 3337 static void gsm_copy_config_values(struct gsm_mux *gsm, 3338 struct gsm_config *c) 3339 { 3340 memset(c, 0, sizeof(*c)); 3341 c->adaption = gsm->adaption; 3342 c->encapsulation = gsm->encoding; 3343 c->initiator = gsm->initiator; 3344 c->t1 = gsm->t1; 3345 c->t2 = gsm->t2; 3346 c->t3 = gsm->t3; 3347 c->n2 = gsm->n2; 3348 if (gsm->ftype == UIH) 3349 c->i = 1; 3350 else 3351 c->i = 2; 3352 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i); 3353 c->mru = gsm->mru; 3354 c->mtu = gsm->mtu; 3355 c->k = gsm->k; 3356 } 3357 3358 static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c) 3359 { 3360 int need_close = 0; 3361 int need_restart = 0; 3362 3363 /* Stuff we don't support yet - UI or I frame transport */ 3364 if (c->adaption != 1 && c->adaption != 2) 3365 return -EOPNOTSUPP; 3366 /* Check the MRU/MTU range looks sane */ 3367 if (c->mru < MIN_MTU || c->mtu < MIN_MTU) 3368 return -EINVAL; 3369 if (c->mru > MAX_MRU || c->mtu > MAX_MTU) 3370 return -EINVAL; 3371 if (c->t3 > MAX_T3) 3372 return -EINVAL; 3373 if (c->n2 > 255) 3374 return -EINVAL; 3375 if (c->encapsulation > 1) /* Basic, advanced, no I */ 3376 return -EINVAL; 3377 if (c->initiator > 1) 3378 return -EINVAL; 3379 if (c->k > MAX_WINDOW_SIZE) 3380 return -EINVAL; 3381 if (c->i == 0 || c->i > 2) /* UIH and UI only */ 3382 return -EINVAL; 3383 /* 3384 * See what is needed for reconfiguration 3385 */ 3386 3387 /* Timing fields */ 3388 if (c->t1 != 0 && c->t1 != gsm->t1) 3389 need_restart = 1; 3390 if (c->t2 != 0 && c->t2 != gsm->t2) 3391 need_restart = 1; 3392 if (c->encapsulation != gsm->encoding) 3393 need_restart = 1; 3394 if (c->adaption != gsm->adaption) 3395 need_restart = 1; 3396 /* Requires care */ 3397 if (c->initiator != gsm->initiator) 3398 need_close = 1; 3399 if (c->mru != gsm->mru) 3400 need_restart = 1; 3401 if (c->mtu != gsm->mtu) 3402 need_restart = 1; 3403 3404 /* 3405 * Close down what is needed, restart and initiate the new 3406 * configuration. On the first time there is no DLCI[0] 3407 * and closing or cleaning up is not necessary. 3408 */ 3409 if (need_close || need_restart) 3410 gsm_cleanup_mux(gsm, true); 3411 3412 gsm->initiator = c->initiator; 3413 gsm->mru = c->mru; 3414 gsm->mtu = c->mtu; 3415 gsm->encoding = c->encapsulation ? GSM_ADV_OPT : GSM_BASIC_OPT; 3416 gsm->adaption = c->adaption; 3417 gsm->n2 = c->n2; 3418 3419 if (c->i == 1) 3420 gsm->ftype = UIH; 3421 else if (c->i == 2) 3422 gsm->ftype = UI; 3423 3424 if (c->t1) 3425 gsm->t1 = c->t1; 3426 if (c->t2) 3427 gsm->t2 = c->t2; 3428 if (c->t3) 3429 gsm->t3 = c->t3; 3430 if (c->k) 3431 gsm->k = c->k; 3432 3433 /* 3434 * FIXME: We need to separate activation/deactivation from adding 3435 * and removing from the mux array 3436 */ 3437 if (gsm->dead) { 3438 int ret = gsm_activate_mux(gsm); 3439 if (ret) 3440 return ret; 3441 if (gsm->initiator) 3442 gsm_dlci_begin_open(gsm->dlci[0]); 3443 } 3444 return 0; 3445 } 3446 3447 static void gsm_copy_config_ext_values(struct gsm_mux *gsm, 3448 struct gsm_config_ext *ce) 3449 { 3450 memset(ce, 0, sizeof(*ce)); 3451 ce->wait_config = gsm->wait_config ? 1 : 0; 3452 ce->keep_alive = gsm->keep_alive; 3453 } 3454 3455 static int gsm_config_ext(struct gsm_mux *gsm, struct gsm_config_ext *ce) 3456 { 3457 bool need_restart = false; 3458 unsigned int i; 3459 3460 /* 3461 * Check that userspace doesn't put stuff in here to prevent breakages 3462 * in the future. 3463 */ 3464 for (i = 0; i < ARRAY_SIZE(ce->reserved); i++) 3465 if (ce->reserved[i]) 3466 return -EINVAL; 3467 if (ce->flags & ~GSM_FL_RESTART) 3468 return -EINVAL; 3469 3470 /* Requires care */ 3471 if (ce->flags & GSM_FL_RESTART) 3472 need_restart = true; 3473 3474 /* 3475 * Close down what is needed, restart and initiate the new 3476 * configuration. On the first time there is no DLCI[0] 3477 * and closing or cleaning up is not necessary. 3478 */ 3479 if (need_restart) 3480 gsm_cleanup_mux(gsm, true); 3481 3482 /* 3483 * Setup the new configuration values 3484 */ 3485 gsm->wait_config = ce->wait_config ? true : false; 3486 gsm->keep_alive = ce->keep_alive; 3487 3488 if (gsm->dead) { 3489 int ret = gsm_activate_mux(gsm); 3490 if (ret) 3491 return ret; 3492 if (gsm->initiator) 3493 gsm_dlci_begin_open(gsm->dlci[0]); 3494 } 3495 3496 return 0; 3497 } 3498 3499 /** 3500 * gsmld_output - write to link 3501 * @gsm: our mux 3502 * @data: bytes to output 3503 * @len: size 3504 * 3505 * Write a block of data from the GSM mux to the data channel. This 3506 * will eventually be serialized from above but at the moment isn't. 3507 */ 3508 3509 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len) 3510 { 3511 if (tty_write_room(gsm->tty) < len) { 3512 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags); 3513 return -ENOSPC; 3514 } 3515 if (debug & DBG_DATA) 3516 gsm_hex_dump_bytes(__func__, data, len); 3517 return gsm->tty->ops->write(gsm->tty, data, len); 3518 } 3519 3520 3521 /** 3522 * gsmld_write_trigger - schedule ldisc write task 3523 * @gsm: our mux 3524 */ 3525 static void gsmld_write_trigger(struct gsm_mux *gsm) 3526 { 3527 if (!gsm || !gsm->dlci[0] || gsm->dlci[0]->dead) 3528 return; 3529 schedule_work(&gsm->tx_work); 3530 } 3531 3532 3533 /** 3534 * gsmld_write_task - ldisc write task 3535 * @work: our tx write work 3536 * 3537 * Writes out data to the ldisc if possible. We are doing this here to 3538 * avoid dead-locking. This returns if no space or data is left for output. 3539 */ 3540 static void gsmld_write_task(struct work_struct *work) 3541 { 3542 struct gsm_mux *gsm = container_of(work, struct gsm_mux, tx_work); 3543 unsigned long flags; 3544 int i, ret; 3545 3546 /* All outstanding control channel and control messages and one data 3547 * frame is sent. 3548 */ 3549 ret = -ENODEV; 3550 spin_lock_irqsave(&gsm->tx_lock, flags); 3551 if (gsm->tty) 3552 ret = gsm_data_kick(gsm); 3553 spin_unlock_irqrestore(&gsm->tx_lock, flags); 3554 3555 if (ret >= 0) 3556 for (i = 0; i < NUM_DLCI; i++) 3557 if (gsm->dlci[i]) 3558 tty_port_tty_wakeup(&gsm->dlci[i]->port); 3559 } 3560 3561 /** 3562 * gsmld_attach_gsm - mode set up 3563 * @tty: our tty structure 3564 * @gsm: our mux 3565 * 3566 * Set up the MUX for basic mode and commence connecting to the 3567 * modem. Currently called from the line discipline set up but 3568 * will need moving to an ioctl path. 3569 */ 3570 3571 static void gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 3572 { 3573 gsm->tty = tty_kref_get(tty); 3574 /* Turn off tty XON/XOFF handling to handle it explicitly. */ 3575 gsm->old_c_iflag = tty->termios.c_iflag; 3576 tty->termios.c_iflag &= (IXON | IXOFF); 3577 } 3578 3579 /** 3580 * gsmld_detach_gsm - stop doing 0710 mux 3581 * @tty: tty attached to the mux 3582 * @gsm: mux 3583 * 3584 * Shutdown and then clean up the resources used by the line discipline 3585 */ 3586 3587 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 3588 { 3589 WARN_ON(tty != gsm->tty); 3590 /* Restore tty XON/XOFF handling. */ 3591 gsm->tty->termios.c_iflag = gsm->old_c_iflag; 3592 tty_kref_put(gsm->tty); 3593 gsm->tty = NULL; 3594 } 3595 3596 static void gsmld_receive_buf(struct tty_struct *tty, const u8 *cp, 3597 const u8 *fp, size_t count) 3598 { 3599 struct gsm_mux *gsm = tty->disc_data; 3600 u8 flags = TTY_NORMAL; 3601 3602 if (debug & DBG_DATA) 3603 gsm_hex_dump_bytes(__func__, cp, count); 3604 3605 for (; count; count--, cp++) { 3606 if (fp) 3607 flags = *fp++; 3608 switch (flags) { 3609 case TTY_NORMAL: 3610 if (gsm->receive) 3611 gsm->receive(gsm, *cp); 3612 break; 3613 case TTY_OVERRUN: 3614 case TTY_BREAK: 3615 case TTY_PARITY: 3616 case TTY_FRAME: 3617 gsm_error(gsm); 3618 break; 3619 default: 3620 WARN_ONCE(1, "%s: unknown flag %d\n", 3621 tty_name(tty), flags); 3622 break; 3623 } 3624 } 3625 /* FASYNC if needed ? */ 3626 /* If clogged call tty_throttle(tty); */ 3627 } 3628 3629 /** 3630 * gsmld_flush_buffer - clean input queue 3631 * @tty: terminal device 3632 * 3633 * Flush the input buffer. Called when the line discipline is 3634 * being closed, when the tty layer wants the buffer flushed (eg 3635 * at hangup). 3636 */ 3637 3638 static void gsmld_flush_buffer(struct tty_struct *tty) 3639 { 3640 } 3641 3642 /** 3643 * gsmld_close - close the ldisc for this tty 3644 * @tty: device 3645 * 3646 * Called from the terminal layer when this line discipline is 3647 * being shut down, either because of a close or becsuse of a 3648 * discipline change. The function will not be called while other 3649 * ldisc methods are in progress. 3650 */ 3651 3652 static void gsmld_close(struct tty_struct *tty) 3653 { 3654 struct gsm_mux *gsm = tty->disc_data; 3655 3656 /* The ldisc locks and closes the port before calling our close. This 3657 * means we have no way to do a proper disconnect. We will not bother 3658 * to do one. 3659 */ 3660 gsm_cleanup_mux(gsm, false); 3661 3662 gsmld_detach_gsm(tty, gsm); 3663 3664 gsmld_flush_buffer(tty); 3665 /* Do other clean up here */ 3666 mux_put(gsm); 3667 } 3668 3669 /** 3670 * gsmld_open - open an ldisc 3671 * @tty: terminal to open 3672 * 3673 * Called when this line discipline is being attached to the 3674 * terminal device. Can sleep. Called serialized so that no 3675 * other events will occur in parallel. No further open will occur 3676 * until a close. 3677 */ 3678 3679 static int gsmld_open(struct tty_struct *tty) 3680 { 3681 struct gsm_mux *gsm; 3682 3683 if (!capable(CAP_NET_ADMIN)) 3684 return -EPERM; 3685 3686 if (tty->ops->write == NULL) 3687 return -EINVAL; 3688 3689 /* Attach our ldisc data */ 3690 gsm = gsm_alloc_mux(); 3691 if (gsm == NULL) 3692 return -ENOMEM; 3693 3694 tty->disc_data = gsm; 3695 tty->receive_room = 65536; 3696 3697 /* Attach the initial passive connection */ 3698 gsmld_attach_gsm(tty, gsm); 3699 3700 /* The mux will not be activated yet, we wait for correct 3701 * configuration first. 3702 */ 3703 if (gsm->encoding == GSM_BASIC_OPT) 3704 gsm->receive = gsm0_receive; 3705 else 3706 gsm->receive = gsm1_receive; 3707 3708 return 0; 3709 } 3710 3711 /** 3712 * gsmld_write_wakeup - asynchronous I/O notifier 3713 * @tty: tty device 3714 * 3715 * Required for the ptys, serial driver etc. since processes 3716 * that attach themselves to the master and rely on ASYNC 3717 * IO must be woken up 3718 */ 3719 3720 static void gsmld_write_wakeup(struct tty_struct *tty) 3721 { 3722 struct gsm_mux *gsm = tty->disc_data; 3723 3724 /* Queue poll */ 3725 gsmld_write_trigger(gsm); 3726 } 3727 3728 /** 3729 * gsmld_read - read function for tty 3730 * @tty: tty device 3731 * @file: file object 3732 * @buf: userspace buffer pointer 3733 * @nr: size of I/O 3734 * @cookie: unused 3735 * @offset: unused 3736 * 3737 * Perform reads for the line discipline. We are guaranteed that the 3738 * line discipline will not be closed under us but we may get multiple 3739 * parallel readers and must handle this ourselves. We may also get 3740 * a hangup. Always called in user context, may sleep. 3741 * 3742 * This code must be sure never to sleep through a hangup. 3743 */ 3744 3745 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, u8 *buf, 3746 size_t nr, void **cookie, unsigned long offset) 3747 { 3748 return -EOPNOTSUPP; 3749 } 3750 3751 /** 3752 * gsmld_write - write function for tty 3753 * @tty: tty device 3754 * @file: file object 3755 * @buf: userspace buffer pointer 3756 * @nr: size of I/O 3757 * 3758 * Called when the owner of the device wants to send a frame 3759 * itself (or some other control data). The data is transferred 3760 * as-is and must be properly framed and checksummed as appropriate 3761 * by userspace. Frames are either sent whole or not at all as this 3762 * avoids pain user side. 3763 */ 3764 3765 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file, 3766 const u8 *buf, size_t nr) 3767 { 3768 struct gsm_mux *gsm = tty->disc_data; 3769 unsigned long flags; 3770 size_t space; 3771 int ret; 3772 3773 if (!gsm) 3774 return -ENODEV; 3775 3776 ret = -ENOBUFS; 3777 spin_lock_irqsave(&gsm->tx_lock, flags); 3778 space = tty_write_room(tty); 3779 if (space >= nr) 3780 ret = tty->ops->write(tty, buf, nr); 3781 else 3782 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 3783 spin_unlock_irqrestore(&gsm->tx_lock, flags); 3784 3785 return ret; 3786 } 3787 3788 /** 3789 * gsmld_poll - poll method for N_GSM0710 3790 * @tty: terminal device 3791 * @file: file accessing it 3792 * @wait: poll table 3793 * 3794 * Called when the line discipline is asked to poll() for data or 3795 * for special events. This code is not serialized with respect to 3796 * other events save open/close. 3797 * 3798 * This code must be sure never to sleep through a hangup. 3799 * Called without the kernel lock held - fine 3800 */ 3801 3802 static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file, 3803 poll_table *wait) 3804 { 3805 __poll_t mask = 0; 3806 struct gsm_mux *gsm = tty->disc_data; 3807 3808 poll_wait(file, &tty->read_wait, wait); 3809 poll_wait(file, &tty->write_wait, wait); 3810 3811 if (gsm->dead) 3812 mask |= EPOLLHUP; 3813 if (tty_hung_up_p(file)) 3814 mask |= EPOLLHUP; 3815 if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) 3816 mask |= EPOLLHUP; 3817 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0) 3818 mask |= EPOLLOUT | EPOLLWRNORM; 3819 return mask; 3820 } 3821 3822 static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd, 3823 unsigned long arg) 3824 { 3825 struct gsm_config c; 3826 struct gsm_config_ext ce; 3827 struct gsm_dlci_config dc; 3828 struct gsm_mux *gsm = tty->disc_data; 3829 unsigned int base, addr; 3830 struct gsm_dlci *dlci; 3831 3832 switch (cmd) { 3833 case GSMIOC_GETCONF: 3834 gsm_copy_config_values(gsm, &c); 3835 if (copy_to_user((void __user *)arg, &c, sizeof(c))) 3836 return -EFAULT; 3837 return 0; 3838 case GSMIOC_SETCONF: 3839 if (copy_from_user(&c, (void __user *)arg, sizeof(c))) 3840 return -EFAULT; 3841 return gsm_config(gsm, &c); 3842 case GSMIOC_GETFIRST: 3843 base = mux_num_to_base(gsm); 3844 return put_user(base + 1, (__u32 __user *)arg); 3845 case GSMIOC_GETCONF_EXT: 3846 gsm_copy_config_ext_values(gsm, &ce); 3847 if (copy_to_user((void __user *)arg, &ce, sizeof(ce))) 3848 return -EFAULT; 3849 return 0; 3850 case GSMIOC_SETCONF_EXT: 3851 if (copy_from_user(&ce, (void __user *)arg, sizeof(ce))) 3852 return -EFAULT; 3853 return gsm_config_ext(gsm, &ce); 3854 case GSMIOC_GETCONF_DLCI: 3855 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc))) 3856 return -EFAULT; 3857 if (dc.channel == 0 || dc.channel >= NUM_DLCI) 3858 return -EINVAL; 3859 addr = array_index_nospec(dc.channel, NUM_DLCI); 3860 dlci = gsm->dlci[addr]; 3861 if (!dlci) { 3862 dlci = gsm_dlci_alloc(gsm, addr); 3863 if (!dlci) 3864 return -ENOMEM; 3865 } 3866 gsm_dlci_copy_config_values(dlci, &dc); 3867 if (copy_to_user((void __user *)arg, &dc, sizeof(dc))) 3868 return -EFAULT; 3869 return 0; 3870 case GSMIOC_SETCONF_DLCI: 3871 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc))) 3872 return -EFAULT; 3873 if (dc.channel == 0 || dc.channel >= NUM_DLCI) 3874 return -EINVAL; 3875 addr = array_index_nospec(dc.channel, NUM_DLCI); 3876 dlci = gsm->dlci[addr]; 3877 if (!dlci) { 3878 dlci = gsm_dlci_alloc(gsm, addr); 3879 if (!dlci) 3880 return -ENOMEM; 3881 } 3882 return gsm_dlci_config(dlci, &dc, 0); 3883 default: 3884 return n_tty_ioctl_helper(tty, cmd, arg); 3885 } 3886 } 3887 3888 /* 3889 * Network interface 3890 * 3891 */ 3892 3893 static int gsm_mux_net_open(struct net_device *net) 3894 { 3895 pr_debug("%s called\n", __func__); 3896 netif_start_queue(net); 3897 return 0; 3898 } 3899 3900 static int gsm_mux_net_close(struct net_device *net) 3901 { 3902 netif_stop_queue(net); 3903 return 0; 3904 } 3905 3906 static void dlci_net_free(struct gsm_dlci *dlci) 3907 { 3908 if (!dlci->net) { 3909 WARN_ON(1); 3910 return; 3911 } 3912 dlci->adaption = dlci->prev_adaption; 3913 dlci->data = dlci->prev_data; 3914 free_netdev(dlci->net); 3915 dlci->net = NULL; 3916 } 3917 static void net_free(struct kref *ref) 3918 { 3919 struct gsm_mux_net *mux_net; 3920 struct gsm_dlci *dlci; 3921 3922 mux_net = container_of(ref, struct gsm_mux_net, ref); 3923 dlci = mux_net->dlci; 3924 3925 if (dlci->net) { 3926 unregister_netdev(dlci->net); 3927 dlci_net_free(dlci); 3928 } 3929 } 3930 3931 static inline void muxnet_get(struct gsm_mux_net *mux_net) 3932 { 3933 kref_get(&mux_net->ref); 3934 } 3935 3936 static inline void muxnet_put(struct gsm_mux_net *mux_net) 3937 { 3938 kref_put(&mux_net->ref, net_free); 3939 } 3940 3941 static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb, 3942 struct net_device *net) 3943 { 3944 struct gsm_mux_net *mux_net = netdev_priv(net); 3945 struct gsm_dlci *dlci = mux_net->dlci; 3946 muxnet_get(mux_net); 3947 3948 skb_queue_head(&dlci->skb_list, skb); 3949 net->stats.tx_packets++; 3950 net->stats.tx_bytes += skb->len; 3951 gsm_dlci_data_kick(dlci); 3952 /* And tell the kernel when the last transmit started. */ 3953 netif_trans_update(net); 3954 muxnet_put(mux_net); 3955 return NETDEV_TX_OK; 3956 } 3957 3958 /* called when a packet did not ack after watchdogtimeout */ 3959 static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue) 3960 { 3961 /* Tell syslog we are hosed. */ 3962 dev_dbg(&net->dev, "Tx timed out.\n"); 3963 3964 /* Update statistics */ 3965 net->stats.tx_errors++; 3966 } 3967 3968 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci, const u8 *in_buf, int size) 3969 { 3970 struct net_device *net = dlci->net; 3971 struct sk_buff *skb; 3972 struct gsm_mux_net *mux_net = netdev_priv(net); 3973 muxnet_get(mux_net); 3974 3975 /* Allocate an sk_buff */ 3976 skb = dev_alloc_skb(size + NET_IP_ALIGN); 3977 if (!skb) { 3978 /* We got no receive buffer. */ 3979 net->stats.rx_dropped++; 3980 muxnet_put(mux_net); 3981 return; 3982 } 3983 skb_reserve(skb, NET_IP_ALIGN); 3984 skb_put_data(skb, in_buf, size); 3985 3986 skb->dev = net; 3987 skb->protocol = htons(ETH_P_IP); 3988 3989 /* Ship it off to the kernel */ 3990 netif_rx(skb); 3991 3992 /* update out statistics */ 3993 net->stats.rx_packets++; 3994 net->stats.rx_bytes += size; 3995 muxnet_put(mux_net); 3996 return; 3997 } 3998 3999 static void gsm_mux_net_init(struct net_device *net) 4000 { 4001 static const struct net_device_ops gsm_netdev_ops = { 4002 .ndo_open = gsm_mux_net_open, 4003 .ndo_stop = gsm_mux_net_close, 4004 .ndo_start_xmit = gsm_mux_net_start_xmit, 4005 .ndo_tx_timeout = gsm_mux_net_tx_timeout, 4006 }; 4007 4008 net->netdev_ops = &gsm_netdev_ops; 4009 4010 /* fill in the other fields */ 4011 net->watchdog_timeo = GSM_NET_TX_TIMEOUT; 4012 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 4013 net->type = ARPHRD_NONE; 4014 net->tx_queue_len = 10; 4015 } 4016 4017 4018 /* caller holds the dlci mutex */ 4019 static void gsm_destroy_network(struct gsm_dlci *dlci) 4020 { 4021 struct gsm_mux_net *mux_net; 4022 4023 pr_debug("destroy network interface\n"); 4024 if (!dlci->net) 4025 return; 4026 mux_net = netdev_priv(dlci->net); 4027 muxnet_put(mux_net); 4028 } 4029 4030 4031 /* caller holds the dlci mutex */ 4032 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc) 4033 { 4034 char *netname; 4035 int retval = 0; 4036 struct net_device *net; 4037 struct gsm_mux_net *mux_net; 4038 4039 if (!capable(CAP_NET_ADMIN)) 4040 return -EPERM; 4041 4042 /* Already in a non tty mode */ 4043 if (dlci->adaption > 2) 4044 return -EBUSY; 4045 4046 if (nc->protocol != htons(ETH_P_IP)) 4047 return -EPROTONOSUPPORT; 4048 4049 if (nc->adaption != 3 && nc->adaption != 4) 4050 return -EPROTONOSUPPORT; 4051 4052 pr_debug("create network interface\n"); 4053 4054 netname = "gsm%d"; 4055 if (nc->if_name[0] != '\0') 4056 netname = nc->if_name; 4057 net = alloc_netdev(sizeof(struct gsm_mux_net), netname, 4058 NET_NAME_UNKNOWN, gsm_mux_net_init); 4059 if (!net) { 4060 pr_err("alloc_netdev failed\n"); 4061 return -ENOMEM; 4062 } 4063 net->mtu = dlci->mtu; 4064 net->min_mtu = MIN_MTU; 4065 net->max_mtu = dlci->mtu; 4066 mux_net = netdev_priv(net); 4067 mux_net->dlci = dlci; 4068 kref_init(&mux_net->ref); 4069 strscpy(nc->if_name, net->name); /* return net name */ 4070 4071 /* reconfigure dlci for network */ 4072 dlci->prev_adaption = dlci->adaption; 4073 dlci->prev_data = dlci->data; 4074 dlci->adaption = nc->adaption; 4075 dlci->data = gsm_mux_rx_netchar; 4076 dlci->net = net; 4077 4078 pr_debug("register netdev\n"); 4079 retval = register_netdev(net); 4080 if (retval) { 4081 pr_err("network register fail %d\n", retval); 4082 dlci_net_free(dlci); 4083 return retval; 4084 } 4085 return net->ifindex; /* return network index */ 4086 } 4087 4088 /* Line discipline for real tty */ 4089 static struct tty_ldisc_ops tty_ldisc_packet = { 4090 .owner = THIS_MODULE, 4091 .num = N_GSM0710, 4092 .name = "n_gsm", 4093 .open = gsmld_open, 4094 .close = gsmld_close, 4095 .flush_buffer = gsmld_flush_buffer, 4096 .read = gsmld_read, 4097 .write = gsmld_write, 4098 .ioctl = gsmld_ioctl, 4099 .poll = gsmld_poll, 4100 .receive_buf = gsmld_receive_buf, 4101 .write_wakeup = gsmld_write_wakeup 4102 }; 4103 4104 /* 4105 * Virtual tty side 4106 */ 4107 4108 /** 4109 * gsm_modem_upd_via_data - send modem bits via convergence layer 4110 * @dlci: channel 4111 * @brk: break signal 4112 * 4113 * Send an empty frame to signal mobile state changes and to transmit the 4114 * break signal for adaption 2. 4115 */ 4116 4117 static void gsm_modem_upd_via_data(struct gsm_dlci *dlci, u8 brk) 4118 { 4119 struct gsm_mux *gsm = dlci->gsm; 4120 unsigned long flags; 4121 4122 if (dlci->state != DLCI_OPEN || dlci->adaption != 2) 4123 return; 4124 4125 spin_lock_irqsave(&gsm->tx_lock, flags); 4126 gsm_dlci_modem_output(gsm, dlci, brk); 4127 spin_unlock_irqrestore(&gsm->tx_lock, flags); 4128 } 4129 4130 /** 4131 * gsm_modem_upd_via_msc - send modem bits via control frame 4132 * @dlci: channel 4133 * @brk: break signal 4134 */ 4135 4136 static int gsm_modem_upd_via_msc(struct gsm_dlci *dlci, u8 brk) 4137 { 4138 u8 modembits[3]; 4139 struct gsm_control *ctrl; 4140 int len = 2; 4141 4142 if (dlci->gsm->encoding != GSM_BASIC_OPT) 4143 return 0; 4144 4145 modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */ 4146 if (!brk) { 4147 modembits[1] = (gsm_encode_modem(dlci) << 1) | EA; 4148 } else { 4149 modembits[1] = gsm_encode_modem(dlci) << 1; 4150 modembits[2] = (brk << 4) | 2 | EA; /* Length, Break, EA */ 4151 len++; 4152 } 4153 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len); 4154 if (ctrl == NULL) 4155 return -ENOMEM; 4156 return gsm_control_wait(dlci->gsm, ctrl); 4157 } 4158 4159 /** 4160 * gsm_modem_update - send modem status line state 4161 * @dlci: channel 4162 * @brk: break signal 4163 */ 4164 4165 static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk) 4166 { 4167 if (dlci->gsm->dead) 4168 return -EL2HLT; 4169 if (dlci->adaption == 2) { 4170 /* Send convergence layer type 2 empty data frame. */ 4171 gsm_modem_upd_via_data(dlci, brk); 4172 return 0; 4173 } else if (dlci->gsm->encoding == GSM_BASIC_OPT) { 4174 /* Send as MSC control message. */ 4175 return gsm_modem_upd_via_msc(dlci, brk); 4176 } 4177 4178 /* Modem status lines are not supported. */ 4179 return -EPROTONOSUPPORT; 4180 } 4181 4182 /** 4183 * gsm_wait_modem_change - wait for modem status line change 4184 * @dlci: channel 4185 * @mask: modem status line bits 4186 * 4187 * The function returns if: 4188 * - any given modem status line bit changed 4189 * - the wait event function got interrupted (e.g. by a signal) 4190 * - the underlying DLCI was closed 4191 * - the underlying ldisc device was removed 4192 */ 4193 static int gsm_wait_modem_change(struct gsm_dlci *dlci, u32 mask) 4194 { 4195 struct gsm_mux *gsm = dlci->gsm; 4196 u32 old = dlci->modem_rx; 4197 int ret; 4198 4199 ret = wait_event_interruptible(gsm->event, gsm->dead || 4200 dlci->state != DLCI_OPEN || 4201 (old ^ dlci->modem_rx) & mask); 4202 if (gsm->dead) 4203 return -ENODEV; 4204 if (dlci->state != DLCI_OPEN) 4205 return -EL2NSYNC; 4206 return ret; 4207 } 4208 4209 static bool gsm_carrier_raised(struct tty_port *port) 4210 { 4211 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 4212 struct gsm_mux *gsm = dlci->gsm; 4213 4214 /* Not yet open so no carrier info */ 4215 if (dlci->state != DLCI_OPEN) 4216 return false; 4217 if (debug & DBG_CD_ON) 4218 return true; 4219 4220 /* 4221 * Basic mode with control channel in ADM mode may not respond 4222 * to CMD_MSC at all and modem_rx is empty. 4223 */ 4224 if (gsm->encoding == GSM_BASIC_OPT && 4225 gsm->dlci[0]->mode == DLCI_MODE_ADM && !dlci->modem_rx) 4226 return true; 4227 4228 return dlci->modem_rx & TIOCM_CD; 4229 } 4230 4231 static void gsm_dtr_rts(struct tty_port *port, bool active) 4232 { 4233 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 4234 unsigned int modem_tx = dlci->modem_tx; 4235 if (active) 4236 modem_tx |= TIOCM_DTR | TIOCM_RTS; 4237 else 4238 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); 4239 if (modem_tx != dlci->modem_tx) { 4240 dlci->modem_tx = modem_tx; 4241 gsm_modem_update(dlci, 0); 4242 } 4243 } 4244 4245 static const struct tty_port_operations gsm_port_ops = { 4246 .carrier_raised = gsm_carrier_raised, 4247 .dtr_rts = gsm_dtr_rts, 4248 .destruct = gsm_dlci_free, 4249 }; 4250 4251 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty) 4252 { 4253 struct gsm_mux *gsm; 4254 struct gsm_dlci *dlci; 4255 unsigned int line = tty->index; 4256 unsigned int mux = mux_line_to_num(line); 4257 bool alloc = false; 4258 int ret; 4259 4260 line = line & 0x3F; 4261 4262 if (mux >= MAX_MUX) 4263 return -ENXIO; 4264 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */ 4265 if (gsm_mux[mux] == NULL) 4266 return -EUNATCH; 4267 if (line == 0 || line > 61) /* 62/63 reserved */ 4268 return -ECHRNG; 4269 gsm = gsm_mux[mux]; 4270 if (gsm->dead) 4271 return -EL2HLT; 4272 /* If DLCI 0 is not yet fully open return an error. 4273 This is ok from a locking 4274 perspective as we don't have to worry about this 4275 if DLCI0 is lost */ 4276 mutex_lock(&gsm->mutex); 4277 if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) { 4278 mutex_unlock(&gsm->mutex); 4279 return -EL2NSYNC; 4280 } 4281 dlci = gsm->dlci[line]; 4282 if (dlci == NULL) { 4283 alloc = true; 4284 dlci = gsm_dlci_alloc(gsm, line); 4285 } 4286 if (dlci == NULL) { 4287 mutex_unlock(&gsm->mutex); 4288 return -ENOMEM; 4289 } 4290 ret = tty_port_install(&dlci->port, driver, tty); 4291 if (ret) { 4292 if (alloc) 4293 dlci_put(dlci); 4294 mutex_unlock(&gsm->mutex); 4295 return ret; 4296 } 4297 4298 dlci_get(dlci); 4299 dlci_get(gsm->dlci[0]); 4300 mux_get(gsm); 4301 tty->driver_data = dlci; 4302 mutex_unlock(&gsm->mutex); 4303 4304 return 0; 4305 } 4306 4307 static int gsmtty_open(struct tty_struct *tty, struct file *filp) 4308 { 4309 struct gsm_dlci *dlci = tty->driver_data; 4310 struct tty_port *port = &dlci->port; 4311 4312 port->count++; 4313 tty_port_tty_set(port, tty); 4314 4315 dlci->modem_rx = 0; 4316 /* We could in theory open and close before we wait - eg if we get 4317 a DM straight back. This is ok as that will have caused a hangup */ 4318 tty_port_set_initialized(port, true); 4319 /* Start sending off SABM messages */ 4320 if (!dlci->gsm->wait_config) { 4321 /* Start sending off SABM messages */ 4322 if (dlci->gsm->initiator) 4323 gsm_dlci_begin_open(dlci); 4324 else 4325 gsm_dlci_set_opening(dlci); 4326 } else { 4327 gsm_dlci_set_wait_config(dlci); 4328 } 4329 /* And wait for virtual carrier */ 4330 return tty_port_block_til_ready(port, tty, filp); 4331 } 4332 4333 static void gsmtty_close(struct tty_struct *tty, struct file *filp) 4334 { 4335 struct gsm_dlci *dlci = tty->driver_data; 4336 4337 if (dlci == NULL) 4338 return; 4339 if (dlci->state == DLCI_CLOSED) 4340 return; 4341 mutex_lock(&dlci->mutex); 4342 gsm_destroy_network(dlci); 4343 mutex_unlock(&dlci->mutex); 4344 if (tty_port_close_start(&dlci->port, tty, filp) == 0) 4345 return; 4346 gsm_dlci_begin_close(dlci); 4347 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty)) 4348 tty_port_lower_dtr_rts(&dlci->port); 4349 tty_port_close_end(&dlci->port, tty); 4350 tty_port_tty_set(&dlci->port, NULL); 4351 return; 4352 } 4353 4354 static void gsmtty_hangup(struct tty_struct *tty) 4355 { 4356 struct gsm_dlci *dlci = tty->driver_data; 4357 if (dlci->state == DLCI_CLOSED) 4358 return; 4359 tty_port_hangup(&dlci->port); 4360 gsm_dlci_begin_close(dlci); 4361 } 4362 4363 static ssize_t gsmtty_write(struct tty_struct *tty, const u8 *buf, size_t len) 4364 { 4365 int sent; 4366 struct gsm_dlci *dlci = tty->driver_data; 4367 if (dlci->state == DLCI_CLOSED) 4368 return -EINVAL; 4369 /* Stuff the bytes into the fifo queue */ 4370 sent = kfifo_in_locked(&dlci->fifo, buf, len, &dlci->lock); 4371 /* Need to kick the channel */ 4372 gsm_dlci_data_kick(dlci); 4373 return sent; 4374 } 4375 4376 static unsigned int gsmtty_write_room(struct tty_struct *tty) 4377 { 4378 struct gsm_dlci *dlci = tty->driver_data; 4379 if (dlci->state == DLCI_CLOSED) 4380 return 0; 4381 return kfifo_avail(&dlci->fifo); 4382 } 4383 4384 static unsigned int gsmtty_chars_in_buffer(struct tty_struct *tty) 4385 { 4386 struct gsm_dlci *dlci = tty->driver_data; 4387 if (dlci->state == DLCI_CLOSED) 4388 return 0; 4389 return kfifo_len(&dlci->fifo); 4390 } 4391 4392 static void gsmtty_flush_buffer(struct tty_struct *tty) 4393 { 4394 struct gsm_dlci *dlci = tty->driver_data; 4395 unsigned long flags; 4396 4397 if (dlci->state == DLCI_CLOSED) 4398 return; 4399 /* Caution needed: If we implement reliable transport classes 4400 then the data being transmitted can't simply be junked once 4401 it has first hit the stack. Until then we can just blow it 4402 away */ 4403 spin_lock_irqsave(&dlci->lock, flags); 4404 kfifo_reset(&dlci->fifo); 4405 spin_unlock_irqrestore(&dlci->lock, flags); 4406 /* Need to unhook this DLCI from the transmit queue logic */ 4407 } 4408 4409 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout) 4410 { 4411 /* The FIFO handles the queue so the kernel will do the right 4412 thing waiting on chars_in_buffer before calling us. No work 4413 to do here */ 4414 } 4415 4416 static int gsmtty_tiocmget(struct tty_struct *tty) 4417 { 4418 struct gsm_dlci *dlci = tty->driver_data; 4419 if (dlci->state == DLCI_CLOSED) 4420 return -EINVAL; 4421 return dlci->modem_rx; 4422 } 4423 4424 static int gsmtty_tiocmset(struct tty_struct *tty, 4425 unsigned int set, unsigned int clear) 4426 { 4427 struct gsm_dlci *dlci = tty->driver_data; 4428 unsigned int modem_tx = dlci->modem_tx; 4429 4430 if (dlci->state == DLCI_CLOSED) 4431 return -EINVAL; 4432 modem_tx &= ~clear; 4433 modem_tx |= set; 4434 4435 if (modem_tx != dlci->modem_tx) { 4436 dlci->modem_tx = modem_tx; 4437 return gsm_modem_update(dlci, 0); 4438 } 4439 return 0; 4440 } 4441 4442 4443 static int gsmtty_ioctl(struct tty_struct *tty, 4444 unsigned int cmd, unsigned long arg) 4445 { 4446 struct gsm_dlci *dlci = tty->driver_data; 4447 struct gsm_netconfig nc; 4448 struct gsm_dlci_config dc; 4449 int index; 4450 4451 if (dlci->state == DLCI_CLOSED) 4452 return -EINVAL; 4453 switch (cmd) { 4454 case GSMIOC_ENABLE_NET: 4455 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc))) 4456 return -EFAULT; 4457 nc.if_name[IFNAMSIZ-1] = '\0'; 4458 /* return net interface index or error code */ 4459 mutex_lock(&dlci->mutex); 4460 index = gsm_create_network(dlci, &nc); 4461 mutex_unlock(&dlci->mutex); 4462 if (copy_to_user((void __user *)arg, &nc, sizeof(nc))) 4463 return -EFAULT; 4464 return index; 4465 case GSMIOC_DISABLE_NET: 4466 if (!capable(CAP_NET_ADMIN)) 4467 return -EPERM; 4468 mutex_lock(&dlci->mutex); 4469 gsm_destroy_network(dlci); 4470 mutex_unlock(&dlci->mutex); 4471 return 0; 4472 case GSMIOC_GETCONF_DLCI: 4473 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc))) 4474 return -EFAULT; 4475 if (dc.channel != dlci->addr) 4476 return -EPERM; 4477 gsm_dlci_copy_config_values(dlci, &dc); 4478 if (copy_to_user((void __user *)arg, &dc, sizeof(dc))) 4479 return -EFAULT; 4480 return 0; 4481 case GSMIOC_SETCONF_DLCI: 4482 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc))) 4483 return -EFAULT; 4484 if (dc.channel >= NUM_DLCI) 4485 return -EINVAL; 4486 if (dc.channel != 0 && dc.channel != dlci->addr) 4487 return -EPERM; 4488 return gsm_dlci_config(dlci, &dc, 1); 4489 case TIOCMIWAIT: 4490 return gsm_wait_modem_change(dlci, (u32)arg); 4491 default: 4492 return -ENOIOCTLCMD; 4493 } 4494 } 4495 4496 static void gsmtty_set_termios(struct tty_struct *tty, 4497 const struct ktermios *old) 4498 { 4499 struct gsm_dlci *dlci = tty->driver_data; 4500 if (dlci->state == DLCI_CLOSED) 4501 return; 4502 /* For the moment its fixed. In actual fact the speed information 4503 for the virtual channel can be propogated in both directions by 4504 the RPN control message. This however rapidly gets nasty as we 4505 then have to remap modem signals each way according to whether 4506 our virtual cable is null modem etc .. */ 4507 tty_termios_copy_hw(&tty->termios, old); 4508 } 4509 4510 static void gsmtty_throttle(struct tty_struct *tty) 4511 { 4512 struct gsm_dlci *dlci = tty->driver_data; 4513 if (dlci->state == DLCI_CLOSED) 4514 return; 4515 if (C_CRTSCTS(tty)) 4516 dlci->modem_tx &= ~TIOCM_RTS; 4517 dlci->throttled = true; 4518 /* Send an MSC with RTS cleared */ 4519 gsm_modem_update(dlci, 0); 4520 } 4521 4522 static void gsmtty_unthrottle(struct tty_struct *tty) 4523 { 4524 struct gsm_dlci *dlci = tty->driver_data; 4525 if (dlci->state == DLCI_CLOSED) 4526 return; 4527 if (C_CRTSCTS(tty)) 4528 dlci->modem_tx |= TIOCM_RTS; 4529 dlci->throttled = false; 4530 /* Send an MSC with RTS set */ 4531 gsm_modem_update(dlci, 0); 4532 } 4533 4534 static int gsmtty_break_ctl(struct tty_struct *tty, int state) 4535 { 4536 struct gsm_dlci *dlci = tty->driver_data; 4537 int encode = 0; /* Off */ 4538 if (dlci->state == DLCI_CLOSED) 4539 return -EINVAL; 4540 4541 if (state == -1) /* "On indefinitely" - we can't encode this 4542 properly */ 4543 encode = 0x0F; 4544 else if (state > 0) { 4545 encode = state / 200; /* mS to encoding */ 4546 if (encode > 0x0F) 4547 encode = 0x0F; /* Best effort */ 4548 } 4549 return gsm_modem_update(dlci, encode); 4550 } 4551 4552 static void gsmtty_cleanup(struct tty_struct *tty) 4553 { 4554 struct gsm_dlci *dlci = tty->driver_data; 4555 struct gsm_mux *gsm = dlci->gsm; 4556 4557 dlci_put(dlci); 4558 dlci_put(gsm->dlci[0]); 4559 mux_put(gsm); 4560 } 4561 4562 /* Virtual ttys for the demux */ 4563 static const struct tty_operations gsmtty_ops = { 4564 .install = gsmtty_install, 4565 .open = gsmtty_open, 4566 .close = gsmtty_close, 4567 .write = gsmtty_write, 4568 .write_room = gsmtty_write_room, 4569 .chars_in_buffer = gsmtty_chars_in_buffer, 4570 .flush_buffer = gsmtty_flush_buffer, 4571 .ioctl = gsmtty_ioctl, 4572 .throttle = gsmtty_throttle, 4573 .unthrottle = gsmtty_unthrottle, 4574 .set_termios = gsmtty_set_termios, 4575 .hangup = gsmtty_hangup, 4576 .wait_until_sent = gsmtty_wait_until_sent, 4577 .tiocmget = gsmtty_tiocmget, 4578 .tiocmset = gsmtty_tiocmset, 4579 .break_ctl = gsmtty_break_ctl, 4580 .cleanup = gsmtty_cleanup, 4581 }; 4582 4583 4584 4585 static int __init gsm_init(void) 4586 { 4587 /* Fill in our line protocol discipline, and register it */ 4588 int status = tty_register_ldisc(&tty_ldisc_packet); 4589 if (status != 0) { 4590 pr_err("n_gsm: can't register line discipline (err = %d)\n", 4591 status); 4592 return status; 4593 } 4594 4595 gsm_tty_driver = tty_alloc_driver(GSM_TTY_MINORS, TTY_DRIVER_REAL_RAW | 4596 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_HARDWARE_BREAK); 4597 if (IS_ERR(gsm_tty_driver)) { 4598 pr_err("gsm_init: tty allocation failed.\n"); 4599 status = PTR_ERR(gsm_tty_driver); 4600 goto err_unreg_ldisc; 4601 } 4602 gsm_tty_driver->driver_name = "gsmtty"; 4603 gsm_tty_driver->name = "gsmtty"; 4604 gsm_tty_driver->major = 0; /* Dynamic */ 4605 gsm_tty_driver->minor_start = 0; 4606 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; 4607 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL; 4608 gsm_tty_driver->init_termios = tty_std_termios; 4609 /* Fixme */ 4610 gsm_tty_driver->init_termios.c_lflag &= ~ECHO; 4611 tty_set_operations(gsm_tty_driver, &gsmtty_ops); 4612 4613 if (tty_register_driver(gsm_tty_driver)) { 4614 pr_err("gsm_init: tty registration failed.\n"); 4615 status = -EBUSY; 4616 goto err_put_driver; 4617 } 4618 pr_debug("gsm_init: loaded as %d,%d.\n", 4619 gsm_tty_driver->major, gsm_tty_driver->minor_start); 4620 return 0; 4621 err_put_driver: 4622 tty_driver_kref_put(gsm_tty_driver); 4623 err_unreg_ldisc: 4624 tty_unregister_ldisc(&tty_ldisc_packet); 4625 return status; 4626 } 4627 4628 static void __exit gsm_exit(void) 4629 { 4630 tty_unregister_ldisc(&tty_ldisc_packet); 4631 tty_unregister_driver(gsm_tty_driver); 4632 tty_driver_kref_put(gsm_tty_driver); 4633 } 4634 4635 module_init(gsm_init); 4636 module_exit(gsm_exit); 4637 4638 4639 MODULE_DESCRIPTION("GSM 0710 tty multiplexor"); 4640 MODULE_LICENSE("GPL"); 4641 MODULE_ALIAS_LDISC(N_GSM0710); 4642