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 receives DM. 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->addr && gsm->control == (DM | PF)) { 2247 if (debug & DBG_ERRORS) 2248 pr_info("DLCI 0 opening in ADM mode.\n"); 2249 dlci->mode = DLCI_MODE_ADM; 2250 gsm_dlci_open(dlci); 2251 } else if (dlci->retries) { 2252 if (!dlci->addr || !gsm->dlci[0] || 2253 gsm->dlci[0]->state != DLCI_OPENING) { 2254 dlci->retries--; 2255 gsm_command(dlci->gsm, dlci->addr, SABM|PF); 2256 } 2257 2258 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 2259 } else { 2260 gsm->open_error++; 2261 gsm_dlci_begin_close(dlci); /* prevent half open link */ 2262 } 2263 2264 break; 2265 case DLCI_CLOSING: 2266 if (dlci->retries) { 2267 dlci->retries--; 2268 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 2269 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 2270 } else 2271 gsm_dlci_close(dlci); 2272 break; 2273 default: 2274 pr_debug("%s: unhandled state: %d\n", __func__, dlci->state); 2275 break; 2276 } 2277 } 2278 2279 /** 2280 * gsm_dlci_begin_open - start channel open procedure 2281 * @dlci: DLCI to open 2282 * 2283 * Commence opening a DLCI from the Linux side. We issue SABM messages 2284 * to the modem which should then reply with a UA or ADM, at which point 2285 * we will move into open state. Opening is done asynchronously with retry 2286 * running off timers and the responses. 2287 * Parameter negotiation is performed before SABM if required. 2288 */ 2289 2290 static void gsm_dlci_begin_open(struct gsm_dlci *dlci) 2291 { 2292 struct gsm_mux *gsm = dlci ? dlci->gsm : NULL; 2293 bool need_pn = false; 2294 2295 if (!gsm) 2296 return; 2297 2298 if (dlci->addr != 0) { 2299 if (gsm->adaption != 1 || gsm->adaption != dlci->adaption) 2300 need_pn = true; 2301 if (dlci->prio != (roundup(dlci->addr + 1, 8) - 1)) 2302 need_pn = true; 2303 if (gsm->ftype != dlci->ftype) 2304 need_pn = true; 2305 } 2306 2307 switch (dlci->state) { 2308 case DLCI_CLOSED: 2309 case DLCI_WAITING_CONFIG: 2310 case DLCI_CLOSING: 2311 dlci->retries = gsm->n2; 2312 if (!need_pn) { 2313 dlci->state = DLCI_OPENING; 2314 if (!dlci->addr || !gsm->dlci[0] || 2315 gsm->dlci[0]->state != DLCI_OPENING) 2316 gsm_command(gsm, dlci->addr, SABM|PF); 2317 } else { 2318 /* Configure DLCI before setup */ 2319 dlci->state = DLCI_CONFIGURE; 2320 if (gsm_dlci_negotiate(dlci) != 0) { 2321 gsm_dlci_close(dlci); 2322 return; 2323 } 2324 } 2325 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 2326 break; 2327 default: 2328 break; 2329 } 2330 } 2331 2332 /** 2333 * gsm_dlci_set_opening - change state to opening 2334 * @dlci: DLCI to open 2335 * 2336 * Change internal state to wait for DLCI open from initiator side. 2337 * We set off timers and responses upon reception of an SABM. 2338 */ 2339 static void gsm_dlci_set_opening(struct gsm_dlci *dlci) 2340 { 2341 switch (dlci->state) { 2342 case DLCI_CLOSED: 2343 case DLCI_WAITING_CONFIG: 2344 case DLCI_CLOSING: 2345 dlci->state = DLCI_OPENING; 2346 break; 2347 default: 2348 break; 2349 } 2350 } 2351 2352 /** 2353 * gsm_dlci_set_wait_config - wait for channel configuration 2354 * @dlci: DLCI to configure 2355 * 2356 * Wait for a DLCI configuration from the application. 2357 */ 2358 static void gsm_dlci_set_wait_config(struct gsm_dlci *dlci) 2359 { 2360 switch (dlci->state) { 2361 case DLCI_CLOSED: 2362 case DLCI_CLOSING: 2363 dlci->state = DLCI_WAITING_CONFIG; 2364 break; 2365 default: 2366 break; 2367 } 2368 } 2369 2370 /** 2371 * gsm_dlci_begin_close - start channel open procedure 2372 * @dlci: DLCI to open 2373 * 2374 * Commence closing a DLCI from the Linux side. We issue DISC messages 2375 * to the modem which should then reply with a UA, at which point we 2376 * will move into closed state. Closing is done asynchronously with retry 2377 * off timers. We may also receive a DM reply from the other end which 2378 * indicates the channel was already closed. 2379 */ 2380 2381 static void gsm_dlci_begin_close(struct gsm_dlci *dlci) 2382 { 2383 struct gsm_mux *gsm = dlci->gsm; 2384 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING) 2385 return; 2386 dlci->retries = gsm->n2; 2387 dlci->state = DLCI_CLOSING; 2388 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 2389 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 2390 wake_up_interruptible(&gsm->event); 2391 } 2392 2393 /** 2394 * gsm_dlci_data - data arrived 2395 * @dlci: channel 2396 * @data: block of bytes received 2397 * @clen: length of received block 2398 * 2399 * A UI or UIH frame has arrived which contains data for a channel 2400 * other than the control channel. If the relevant virtual tty is 2401 * open we shovel the bits down it, if not we drop them. 2402 */ 2403 2404 static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen) 2405 { 2406 /* krefs .. */ 2407 struct tty_port *port = &dlci->port; 2408 struct tty_struct *tty; 2409 unsigned int modem = 0; 2410 int len; 2411 2412 if (debug & DBG_TTY) 2413 pr_debug("%d bytes for tty\n", clen); 2414 switch (dlci->adaption) { 2415 /* Unsupported types */ 2416 case 4: /* Packetised interruptible data */ 2417 break; 2418 case 3: /* Packetised uininterruptible voice/data */ 2419 break; 2420 case 2: /* Asynchronous serial with line state in each frame */ 2421 len = gsm_read_ea_val(&modem, data, clen); 2422 if (len < 1) 2423 return; 2424 tty = tty_port_tty_get(port); 2425 if (tty) { 2426 gsm_process_modem(tty, dlci, modem, len); 2427 tty_wakeup(tty); 2428 tty_kref_put(tty); 2429 } 2430 /* Skip processed modem data */ 2431 data += len; 2432 clen -= len; 2433 fallthrough; 2434 case 1: /* Line state will go via DLCI 0 controls only */ 2435 default: 2436 tty_insert_flip_string(port, data, clen); 2437 tty_flip_buffer_push(port); 2438 } 2439 } 2440 2441 /** 2442 * gsm_dlci_command - data arrived on control channel 2443 * @dlci: channel 2444 * @data: block of bytes received 2445 * @len: length of received block 2446 * 2447 * A UI or UIH frame has arrived which contains data for DLCI 0 the 2448 * control channel. This should contain a command EA followed by 2449 * control data bytes. The command EA contains a command/response bit 2450 * and we divide up the work accordingly. 2451 */ 2452 2453 static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len) 2454 { 2455 /* See what command is involved */ 2456 unsigned int command = 0; 2457 unsigned int clen = 0; 2458 unsigned int dlen; 2459 2460 /* read the command */ 2461 dlen = gsm_read_ea_val(&command, data, len); 2462 len -= dlen; 2463 data += dlen; 2464 2465 /* read any control data */ 2466 dlen = gsm_read_ea_val(&clen, data, len); 2467 len -= dlen; 2468 data += dlen; 2469 2470 /* Malformed command? */ 2471 if (clen > len) { 2472 dlci->gsm->malformed++; 2473 return; 2474 } 2475 2476 if (command & 1) 2477 gsm_control_message(dlci->gsm, command, data, clen); 2478 else 2479 gsm_control_response(dlci->gsm, command, data, clen); 2480 } 2481 2482 /** 2483 * gsm_kick_timer - transmit if possible 2484 * @t: timer contained in our gsm object 2485 * 2486 * Transmit data from DLCIs if the queue is empty. We can't rely on 2487 * a tty wakeup except when we filled the pipe so we need to fire off 2488 * new data ourselves in other cases. 2489 */ 2490 static void gsm_kick_timer(struct timer_list *t) 2491 { 2492 struct gsm_mux *gsm = from_timer(gsm, t, kick_timer); 2493 unsigned long flags; 2494 int sent = 0; 2495 2496 spin_lock_irqsave(&gsm->tx_lock, flags); 2497 /* If we have nothing running then we need to fire up */ 2498 if (gsm->tx_bytes < TX_THRESH_LO) 2499 sent = gsm_dlci_data_sweep(gsm); 2500 spin_unlock_irqrestore(&gsm->tx_lock, flags); 2501 2502 if (sent && debug & DBG_DATA) 2503 pr_info("%s TX queue stalled\n", __func__); 2504 } 2505 2506 /** 2507 * gsm_dlci_copy_config_values - copy DLCI configuration 2508 * @dlci: source DLCI 2509 * @dc: configuration structure to fill 2510 */ 2511 static void gsm_dlci_copy_config_values(struct gsm_dlci *dlci, struct gsm_dlci_config *dc) 2512 { 2513 memset(dc, 0, sizeof(*dc)); 2514 dc->channel = (u32)dlci->addr; 2515 dc->adaption = (u32)dlci->adaption; 2516 dc->mtu = (u32)dlci->mtu; 2517 dc->priority = (u32)dlci->prio; 2518 if (dlci->ftype == UIH) 2519 dc->i = 1; 2520 else 2521 dc->i = 2; 2522 dc->k = (u32)dlci->k; 2523 } 2524 2525 /** 2526 * gsm_dlci_config - configure DLCI from configuration 2527 * @dlci: DLCI to configure 2528 * @dc: DLCI configuration 2529 * @open: open DLCI after configuration? 2530 */ 2531 static int gsm_dlci_config(struct gsm_dlci *dlci, struct gsm_dlci_config *dc, int open) 2532 { 2533 struct gsm_mux *gsm; 2534 bool need_restart = false; 2535 bool need_open = false; 2536 unsigned int i; 2537 2538 /* 2539 * Check that userspace doesn't put stuff in here to prevent breakages 2540 * in the future. 2541 */ 2542 for (i = 0; i < ARRAY_SIZE(dc->reserved); i++) 2543 if (dc->reserved[i]) 2544 return -EINVAL; 2545 2546 if (!dlci) 2547 return -EINVAL; 2548 gsm = dlci->gsm; 2549 2550 /* Stuff we don't support yet - I frame transport */ 2551 if (dc->adaption != 1 && dc->adaption != 2) 2552 return -EOPNOTSUPP; 2553 if (dc->mtu > MAX_MTU || dc->mtu < MIN_MTU || dc->mtu > gsm->mru) 2554 return -EINVAL; 2555 if (dc->priority >= 64) 2556 return -EINVAL; 2557 if (dc->i == 0 || dc->i > 2) /* UIH and UI only */ 2558 return -EINVAL; 2559 if (dc->k > 7) 2560 return -EINVAL; 2561 if (dc->flags & ~GSM_FL_RESTART) /* allow future extensions */ 2562 return -EINVAL; 2563 2564 /* 2565 * See what is needed for reconfiguration 2566 */ 2567 /* Framing fields */ 2568 if (dc->adaption != dlci->adaption) 2569 need_restart = true; 2570 if (dc->mtu != dlci->mtu) 2571 need_restart = true; 2572 if (dc->i != dlci->ftype) 2573 need_restart = true; 2574 /* Requires care */ 2575 if (dc->priority != dlci->prio) 2576 need_restart = true; 2577 if (dc->flags & GSM_FL_RESTART) 2578 need_restart = true; 2579 2580 if ((open && gsm->wait_config) || need_restart) 2581 need_open = true; 2582 if (dlci->state == DLCI_WAITING_CONFIG) { 2583 need_restart = false; 2584 need_open = true; 2585 } 2586 2587 /* 2588 * Close down what is needed, restart and initiate the new 2589 * configuration. 2590 */ 2591 if (need_restart) { 2592 gsm_dlci_begin_close(dlci); 2593 wait_event_interruptible(gsm->event, dlci->state == DLCI_CLOSED); 2594 if (signal_pending(current)) 2595 return -EINTR; 2596 } 2597 /* 2598 * Setup the new configuration values 2599 */ 2600 dlci->adaption = (int)dc->adaption; 2601 2602 if (dc->mtu) 2603 dlci->mtu = (unsigned int)dc->mtu; 2604 else 2605 dlci->mtu = gsm->mtu; 2606 2607 if (dc->priority) 2608 dlci->prio = (u8)dc->priority; 2609 else 2610 dlci->prio = roundup(dlci->addr + 1, 8) - 1; 2611 2612 if (dc->i == 1) 2613 dlci->ftype = UIH; 2614 else if (dc->i == 2) 2615 dlci->ftype = UI; 2616 2617 if (dc->k) 2618 dlci->k = (u8)dc->k; 2619 else 2620 dlci->k = gsm->k; 2621 2622 if (need_open) { 2623 if (gsm->initiator) 2624 gsm_dlci_begin_open(dlci); 2625 else 2626 gsm_dlci_set_opening(dlci); 2627 } 2628 2629 return 0; 2630 } 2631 2632 /* 2633 * Allocate/Free DLCI channels 2634 */ 2635 2636 /** 2637 * gsm_dlci_alloc - allocate a DLCI 2638 * @gsm: GSM mux 2639 * @addr: address of the DLCI 2640 * 2641 * Allocate and install a new DLCI object into the GSM mux. 2642 * 2643 * FIXME: review locking races 2644 */ 2645 2646 static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr) 2647 { 2648 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC); 2649 if (dlci == NULL) 2650 return NULL; 2651 spin_lock_init(&dlci->lock); 2652 mutex_init(&dlci->mutex); 2653 if (kfifo_alloc(&dlci->fifo, TX_SIZE, GFP_KERNEL) < 0) { 2654 kfree(dlci); 2655 return NULL; 2656 } 2657 2658 skb_queue_head_init(&dlci->skb_list); 2659 timer_setup(&dlci->t1, gsm_dlci_t1, 0); 2660 tty_port_init(&dlci->port); 2661 dlci->port.ops = &gsm_port_ops; 2662 dlci->gsm = gsm; 2663 dlci->addr = addr; 2664 dlci->adaption = gsm->adaption; 2665 dlci->mtu = gsm->mtu; 2666 if (addr == 0) 2667 dlci->prio = 0; 2668 else 2669 dlci->prio = roundup(addr + 1, 8) - 1; 2670 dlci->ftype = gsm->ftype; 2671 dlci->k = gsm->k; 2672 dlci->state = DLCI_CLOSED; 2673 if (addr) { 2674 dlci->data = gsm_dlci_data; 2675 /* Prevent us from sending data before the link is up */ 2676 dlci->constipated = true; 2677 } else { 2678 dlci->data = gsm_dlci_command; 2679 } 2680 gsm->dlci[addr] = dlci; 2681 return dlci; 2682 } 2683 2684 /** 2685 * gsm_dlci_free - free DLCI 2686 * @port: tty port for DLCI to free 2687 * 2688 * Free up a DLCI. 2689 * 2690 * Can sleep. 2691 */ 2692 static void gsm_dlci_free(struct tty_port *port) 2693 { 2694 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2695 2696 timer_shutdown_sync(&dlci->t1); 2697 dlci->gsm->dlci[dlci->addr] = NULL; 2698 kfifo_free(&dlci->fifo); 2699 while ((dlci->skb = skb_dequeue(&dlci->skb_list))) 2700 dev_kfree_skb(dlci->skb); 2701 kfree(dlci); 2702 } 2703 2704 static inline void dlci_get(struct gsm_dlci *dlci) 2705 { 2706 tty_port_get(&dlci->port); 2707 } 2708 2709 static inline void dlci_put(struct gsm_dlci *dlci) 2710 { 2711 tty_port_put(&dlci->port); 2712 } 2713 2714 static void gsm_destroy_network(struct gsm_dlci *dlci); 2715 2716 /** 2717 * gsm_dlci_release - release DLCI 2718 * @dlci: DLCI to destroy 2719 * 2720 * Release a DLCI. Actual free is deferred until either 2721 * mux is closed or tty is closed - whichever is last. 2722 * 2723 * Can sleep. 2724 */ 2725 static void gsm_dlci_release(struct gsm_dlci *dlci) 2726 { 2727 struct tty_struct *tty = tty_port_tty_get(&dlci->port); 2728 if (tty) { 2729 mutex_lock(&dlci->mutex); 2730 gsm_destroy_network(dlci); 2731 mutex_unlock(&dlci->mutex); 2732 2733 /* We cannot use tty_hangup() because in tty_kref_put() the tty 2734 * driver assumes that the hangup queue is free and reuses it to 2735 * queue release_one_tty() -> NULL pointer panic in 2736 * process_one_work(). 2737 */ 2738 tty_vhangup(tty); 2739 2740 tty_port_tty_set(&dlci->port, NULL); 2741 tty_kref_put(tty); 2742 } 2743 dlci->state = DLCI_CLOSED; 2744 dlci_put(dlci); 2745 } 2746 2747 /* 2748 * LAPBish link layer logic 2749 */ 2750 2751 /** 2752 * gsm_queue - a GSM frame is ready to process 2753 * @gsm: pointer to our gsm mux 2754 * 2755 * At this point in time a frame has arrived and been demangled from 2756 * the line encoding. All the differences between the encodings have 2757 * been handled below us and the frame is unpacked into the structures. 2758 * The fcs holds the header FCS but any data FCS must be added here. 2759 */ 2760 2761 static void gsm_queue(struct gsm_mux *gsm) 2762 { 2763 struct gsm_dlci *dlci; 2764 u8 cr; 2765 int address; 2766 2767 if (gsm->fcs != GOOD_FCS) { 2768 gsm->bad_fcs++; 2769 if (debug & DBG_DATA) 2770 pr_debug("BAD FCS %02x\n", gsm->fcs); 2771 return; 2772 } 2773 address = gsm->address >> 1; 2774 if (address >= NUM_DLCI) 2775 goto invalid; 2776 2777 cr = gsm->address & 1; /* C/R bit */ 2778 cr ^= gsm->initiator ? 0 : 1; /* Flip so 1 always means command */ 2779 2780 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len); 2781 2782 dlci = gsm->dlci[address]; 2783 2784 switch (gsm->control) { 2785 case SABM|PF: 2786 if (cr == 1) { 2787 gsm->open_error++; 2788 goto invalid; 2789 } 2790 if (dlci == NULL) 2791 dlci = gsm_dlci_alloc(gsm, address); 2792 if (dlci == NULL) { 2793 gsm->open_error++; 2794 return; 2795 } 2796 if (dlci->dead) 2797 gsm_response(gsm, address, DM|PF); 2798 else { 2799 gsm_response(gsm, address, UA|PF); 2800 gsm_dlci_open(dlci); 2801 } 2802 break; 2803 case DISC|PF: 2804 if (cr == 1) 2805 goto invalid; 2806 if (dlci == NULL || dlci->state == DLCI_CLOSED) { 2807 gsm_response(gsm, address, DM|PF); 2808 return; 2809 } 2810 /* Real close complete */ 2811 gsm_response(gsm, address, UA|PF); 2812 gsm_dlci_close(dlci); 2813 break; 2814 case UA|PF: 2815 if (cr == 0 || dlci == NULL) 2816 break; 2817 switch (dlci->state) { 2818 case DLCI_CLOSING: 2819 gsm_dlci_close(dlci); 2820 break; 2821 case DLCI_OPENING: 2822 gsm_dlci_open(dlci); 2823 break; 2824 default: 2825 pr_debug("%s: unhandled state: %d\n", __func__, 2826 dlci->state); 2827 break; 2828 } 2829 break; 2830 case DM: /* DM can be valid unsolicited */ 2831 case DM|PF: 2832 if (cr) 2833 goto invalid; 2834 if (dlci == NULL) 2835 return; 2836 gsm_dlci_close(dlci); 2837 break; 2838 case UI: 2839 case UI|PF: 2840 case UIH: 2841 case UIH|PF: 2842 if (dlci == NULL || dlci->state != DLCI_OPEN) { 2843 gsm_response(gsm, address, DM|PF); 2844 return; 2845 } 2846 dlci->data(dlci, gsm->buf, gsm->len); 2847 break; 2848 default: 2849 goto invalid; 2850 } 2851 return; 2852 invalid: 2853 gsm->malformed++; 2854 return; 2855 } 2856 2857 /** 2858 * gsm0_receive_state_check_and_fix - check and correct receive state 2859 * @gsm: gsm data for this ldisc instance 2860 * 2861 * Ensures that the current receive state is valid for basic option mode. 2862 */ 2863 2864 static void gsm0_receive_state_check_and_fix(struct gsm_mux *gsm) 2865 { 2866 switch (gsm->state) { 2867 case GSM_SEARCH: 2868 case GSM0_ADDRESS: 2869 case GSM0_CONTROL: 2870 case GSM0_LEN0: 2871 case GSM0_LEN1: 2872 case GSM0_DATA: 2873 case GSM0_FCS: 2874 case GSM0_SSOF: 2875 break; 2876 default: 2877 gsm->state = GSM_SEARCH; 2878 break; 2879 } 2880 } 2881 2882 /** 2883 * gsm0_receive - perform processing for non-transparency 2884 * @gsm: gsm data for this ldisc instance 2885 * @c: character 2886 * 2887 * Receive bytes in gsm mode 0 2888 */ 2889 2890 static void gsm0_receive(struct gsm_mux *gsm, u8 c) 2891 { 2892 unsigned int len; 2893 2894 gsm0_receive_state_check_and_fix(gsm); 2895 switch (gsm->state) { 2896 case GSM_SEARCH: /* SOF marker */ 2897 if (c == GSM0_SOF) { 2898 gsm->state = GSM0_ADDRESS; 2899 gsm->address = 0; 2900 gsm->len = 0; 2901 gsm->fcs = INIT_FCS; 2902 } 2903 break; 2904 case GSM0_ADDRESS: /* Address EA */ 2905 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 2906 if (gsm_read_ea(&gsm->address, c)) 2907 gsm->state = GSM0_CONTROL; 2908 break; 2909 case GSM0_CONTROL: /* Control Byte */ 2910 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 2911 gsm->control = c; 2912 gsm->state = GSM0_LEN0; 2913 break; 2914 case GSM0_LEN0: /* Length EA */ 2915 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 2916 if (gsm_read_ea(&gsm->len, c)) { 2917 if (gsm->len > gsm->mru) { 2918 gsm->bad_size++; 2919 gsm->state = GSM_SEARCH; 2920 break; 2921 } 2922 gsm->count = 0; 2923 if (!gsm->len) 2924 gsm->state = GSM0_FCS; 2925 else 2926 gsm->state = GSM0_DATA; 2927 break; 2928 } 2929 gsm->state = GSM0_LEN1; 2930 break; 2931 case GSM0_LEN1: 2932 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 2933 len = c; 2934 gsm->len |= len << 7; 2935 if (gsm->len > gsm->mru) { 2936 gsm->bad_size++; 2937 gsm->state = GSM_SEARCH; 2938 break; 2939 } 2940 gsm->count = 0; 2941 if (!gsm->len) 2942 gsm->state = GSM0_FCS; 2943 else 2944 gsm->state = GSM0_DATA; 2945 break; 2946 case GSM0_DATA: /* Data */ 2947 gsm->buf[gsm->count++] = c; 2948 if (gsm->count >= MAX_MRU) { 2949 gsm->bad_size++; 2950 gsm->state = GSM_SEARCH; 2951 } else if (gsm->count >= gsm->len) { 2952 /* Calculate final FCS for UI frames over all data */ 2953 if ((gsm->control & ~PF) != UIH) { 2954 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, 2955 gsm->count); 2956 } 2957 gsm->state = GSM0_FCS; 2958 } 2959 break; 2960 case GSM0_FCS: /* FCS follows the packet */ 2961 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 2962 gsm->state = GSM0_SSOF; 2963 break; 2964 case GSM0_SSOF: 2965 gsm->state = GSM_SEARCH; 2966 if (c == GSM0_SOF) 2967 gsm_queue(gsm); 2968 else 2969 gsm->bad_size++; 2970 break; 2971 default: 2972 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state); 2973 break; 2974 } 2975 } 2976 2977 /** 2978 * gsm1_receive_state_check_and_fix - check and correct receive state 2979 * @gsm: gsm data for this ldisc instance 2980 * 2981 * Ensures that the current receive state is valid for advanced option mode. 2982 */ 2983 2984 static void gsm1_receive_state_check_and_fix(struct gsm_mux *gsm) 2985 { 2986 switch (gsm->state) { 2987 case GSM_SEARCH: 2988 case GSM1_START: 2989 case GSM1_ADDRESS: 2990 case GSM1_CONTROL: 2991 case GSM1_DATA: 2992 case GSM1_OVERRUN: 2993 break; 2994 default: 2995 gsm->state = GSM_SEARCH; 2996 break; 2997 } 2998 } 2999 3000 /** 3001 * gsm1_receive - perform processing for non-transparency 3002 * @gsm: gsm data for this ldisc instance 3003 * @c: character 3004 * 3005 * Receive bytes in mode 1 (Advanced option) 3006 */ 3007 3008 static void gsm1_receive(struct gsm_mux *gsm, u8 c) 3009 { 3010 gsm1_receive_state_check_and_fix(gsm); 3011 /* handle XON/XOFF */ 3012 if ((c & ISO_IEC_646_MASK) == XON) { 3013 gsm->constipated = true; 3014 return; 3015 } else if ((c & ISO_IEC_646_MASK) == XOFF) { 3016 gsm->constipated = false; 3017 /* Kick the link in case it is idling */ 3018 gsmld_write_trigger(gsm); 3019 return; 3020 } 3021 if (c == GSM1_SOF) { 3022 /* EOF is only valid in frame if we have got to the data state */ 3023 if (gsm->state == GSM1_DATA) { 3024 if (gsm->count < 1) { 3025 /* Missing FSC */ 3026 gsm->malformed++; 3027 gsm->state = GSM1_START; 3028 return; 3029 } 3030 /* Remove the FCS from data */ 3031 gsm->count--; 3032 if ((gsm->control & ~PF) != UIH) { 3033 /* Calculate final FCS for UI frames over all 3034 * data but FCS 3035 */ 3036 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, 3037 gsm->count); 3038 } 3039 /* Add the FCS itself to test against GOOD_FCS */ 3040 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]); 3041 gsm->len = gsm->count; 3042 gsm_queue(gsm); 3043 gsm->state = GSM1_START; 3044 return; 3045 } 3046 /* Any partial frame was a runt so go back to start */ 3047 if (gsm->state != GSM1_START) { 3048 if (gsm->state != GSM_SEARCH) 3049 gsm->malformed++; 3050 gsm->state = GSM1_START; 3051 } 3052 /* A SOF in GSM_START means we are still reading idling or 3053 framing bytes */ 3054 return; 3055 } 3056 3057 if (c == GSM1_ESCAPE) { 3058 gsm->escape = true; 3059 return; 3060 } 3061 3062 /* Only an unescaped SOF gets us out of GSM search */ 3063 if (gsm->state == GSM_SEARCH) 3064 return; 3065 3066 if (gsm->escape) { 3067 c ^= GSM1_ESCAPE_BITS; 3068 gsm->escape = false; 3069 } 3070 switch (gsm->state) { 3071 case GSM1_START: /* First byte after SOF */ 3072 gsm->address = 0; 3073 gsm->state = GSM1_ADDRESS; 3074 gsm->fcs = INIT_FCS; 3075 fallthrough; 3076 case GSM1_ADDRESS: /* Address continuation */ 3077 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 3078 if (gsm_read_ea(&gsm->address, c)) 3079 gsm->state = GSM1_CONTROL; 3080 break; 3081 case GSM1_CONTROL: /* Control Byte */ 3082 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 3083 gsm->control = c; 3084 gsm->count = 0; 3085 gsm->state = GSM1_DATA; 3086 break; 3087 case GSM1_DATA: /* Data */ 3088 if (gsm->count > gsm->mru || gsm->count > MAX_MRU) { /* Allow one for the FCS */ 3089 gsm->state = GSM1_OVERRUN; 3090 gsm->bad_size++; 3091 } else 3092 gsm->buf[gsm->count++] = c; 3093 break; 3094 case GSM1_OVERRUN: /* Over-long - eg a dropped SOF */ 3095 break; 3096 default: 3097 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state); 3098 break; 3099 } 3100 } 3101 3102 /** 3103 * gsm_error - handle tty error 3104 * @gsm: ldisc data 3105 * 3106 * Handle an error in the receipt of data for a frame. Currently we just 3107 * go back to hunting for a SOF. 3108 * 3109 * FIXME: better diagnostics ? 3110 */ 3111 3112 static void gsm_error(struct gsm_mux *gsm) 3113 { 3114 gsm->state = GSM_SEARCH; 3115 gsm->io_error++; 3116 } 3117 3118 /** 3119 * gsm_cleanup_mux - generic GSM protocol cleanup 3120 * @gsm: our mux 3121 * @disc: disconnect link? 3122 * 3123 * Clean up the bits of the mux which are the same for all framing 3124 * protocols. Remove the mux from the mux table, stop all the timers 3125 * and then shut down each device hanging up the channels as we go. 3126 */ 3127 3128 static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc) 3129 { 3130 int i; 3131 struct gsm_dlci *dlci; 3132 struct gsm_msg *txq, *ntxq; 3133 3134 gsm->dead = true; 3135 mutex_lock(&gsm->mutex); 3136 3137 dlci = gsm->dlci[0]; 3138 if (dlci) { 3139 if (disc && dlci->state != DLCI_CLOSED) { 3140 gsm_dlci_begin_close(dlci); 3141 wait_event(gsm->event, dlci->state == DLCI_CLOSED); 3142 } 3143 dlci->dead = true; 3144 } 3145 3146 /* Finish outstanding timers, making sure they are done */ 3147 del_timer_sync(&gsm->kick_timer); 3148 del_timer_sync(&gsm->t2_timer); 3149 del_timer_sync(&gsm->ka_timer); 3150 3151 /* Finish writing to ldisc */ 3152 flush_work(&gsm->tx_work); 3153 3154 /* Free up any link layer users and finally the control channel */ 3155 if (gsm->has_devices) { 3156 gsm_unregister_devices(gsm_tty_driver, gsm->num); 3157 gsm->has_devices = false; 3158 } 3159 for (i = NUM_DLCI - 1; i >= 0; i--) 3160 if (gsm->dlci[i]) 3161 gsm_dlci_release(gsm->dlci[i]); 3162 mutex_unlock(&gsm->mutex); 3163 /* Now wipe the queues */ 3164 tty_ldisc_flush(gsm->tty); 3165 3166 guard(spinlock_irqsave)(&gsm->tx_lock); 3167 list_for_each_entry_safe(txq, ntxq, &gsm->tx_ctrl_list, list) 3168 kfree(txq); 3169 INIT_LIST_HEAD(&gsm->tx_ctrl_list); 3170 list_for_each_entry_safe(txq, ntxq, &gsm->tx_data_list, list) 3171 kfree(txq); 3172 INIT_LIST_HEAD(&gsm->tx_data_list); 3173 } 3174 3175 /** 3176 * gsm_activate_mux - generic GSM setup 3177 * @gsm: our mux 3178 * 3179 * Set up the bits of the mux which are the same for all framing 3180 * protocols. Add the mux to the mux table so it can be opened and 3181 * finally kick off connecting to DLCI 0 on the modem. 3182 */ 3183 3184 static int gsm_activate_mux(struct gsm_mux *gsm) 3185 { 3186 struct gsm_dlci *dlci; 3187 int ret; 3188 3189 dlci = gsm_dlci_alloc(gsm, 0); 3190 if (dlci == NULL) 3191 return -ENOMEM; 3192 3193 if (gsm->encoding == GSM_BASIC_OPT) 3194 gsm->receive = gsm0_receive; 3195 else 3196 gsm->receive = gsm1_receive; 3197 3198 ret = gsm_register_devices(gsm_tty_driver, gsm->num); 3199 if (ret) 3200 return ret; 3201 3202 gsm->has_devices = true; 3203 gsm->dead = false; /* Tty opens are now permissible */ 3204 return 0; 3205 } 3206 3207 /** 3208 * gsm_free_mux - free up a mux 3209 * @gsm: mux to free 3210 * 3211 * Dispose of allocated resources for a dead mux 3212 */ 3213 static void gsm_free_mux(struct gsm_mux *gsm) 3214 { 3215 int i; 3216 3217 for (i = 0; i < MAX_MUX; i++) { 3218 if (gsm == gsm_mux[i]) { 3219 gsm_mux[i] = NULL; 3220 break; 3221 } 3222 } 3223 mutex_destroy(&gsm->mutex); 3224 kfree(gsm->txframe); 3225 kfree(gsm->buf); 3226 kfree(gsm); 3227 } 3228 3229 /** 3230 * gsm_free_muxr - free up a mux 3231 * @ref: kreference to the mux to free 3232 * 3233 * Dispose of allocated resources for a dead mux 3234 */ 3235 static void gsm_free_muxr(struct kref *ref) 3236 { 3237 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref); 3238 gsm_free_mux(gsm); 3239 } 3240 3241 static inline void mux_get(struct gsm_mux *gsm) 3242 { 3243 unsigned long flags; 3244 3245 spin_lock_irqsave(&gsm_mux_lock, flags); 3246 kref_get(&gsm->ref); 3247 spin_unlock_irqrestore(&gsm_mux_lock, flags); 3248 } 3249 3250 static inline void mux_put(struct gsm_mux *gsm) 3251 { 3252 unsigned long flags; 3253 3254 spin_lock_irqsave(&gsm_mux_lock, flags); 3255 kref_put(&gsm->ref, gsm_free_muxr); 3256 spin_unlock_irqrestore(&gsm_mux_lock, flags); 3257 } 3258 3259 static inline unsigned int mux_num_to_base(struct gsm_mux *gsm) 3260 { 3261 return gsm->num * NUM_DLCI; 3262 } 3263 3264 static inline unsigned int mux_line_to_num(unsigned int line) 3265 { 3266 return line / NUM_DLCI; 3267 } 3268 3269 /** 3270 * gsm_alloc_mux - allocate a mux 3271 * 3272 * Creates a new mux ready for activation. 3273 */ 3274 3275 static struct gsm_mux *gsm_alloc_mux(void) 3276 { 3277 int i; 3278 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL); 3279 if (gsm == NULL) 3280 return NULL; 3281 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL); 3282 if (gsm->buf == NULL) { 3283 kfree(gsm); 3284 return NULL; 3285 } 3286 gsm->txframe = kmalloc(2 * (MAX_MTU + PROT_OVERHEAD - 1), GFP_KERNEL); 3287 if (gsm->txframe == NULL) { 3288 kfree(gsm->buf); 3289 kfree(gsm); 3290 return NULL; 3291 } 3292 spin_lock_init(&gsm->lock); 3293 mutex_init(&gsm->mutex); 3294 kref_init(&gsm->ref); 3295 INIT_LIST_HEAD(&gsm->tx_ctrl_list); 3296 INIT_LIST_HEAD(&gsm->tx_data_list); 3297 timer_setup(&gsm->kick_timer, gsm_kick_timer, 0); 3298 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0); 3299 timer_setup(&gsm->ka_timer, gsm_control_keep_alive, 0); 3300 INIT_WORK(&gsm->tx_work, gsmld_write_task); 3301 init_waitqueue_head(&gsm->event); 3302 spin_lock_init(&gsm->control_lock); 3303 spin_lock_init(&gsm->tx_lock); 3304 3305 gsm->t1 = T1; 3306 gsm->t2 = T2; 3307 gsm->t3 = T3; 3308 gsm->n2 = N2; 3309 gsm->k = K; 3310 gsm->ftype = UIH; 3311 gsm->adaption = 1; 3312 gsm->encoding = GSM_ADV_OPT; 3313 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */ 3314 gsm->mtu = 64; 3315 gsm->dead = true; /* Avoid early tty opens */ 3316 gsm->wait_config = false; /* Disabled */ 3317 gsm->keep_alive = 0; /* Disabled */ 3318 3319 /* Store the instance to the mux array or abort if no space is 3320 * available. 3321 */ 3322 spin_lock(&gsm_mux_lock); 3323 for (i = 0; i < MAX_MUX; i++) { 3324 if (!gsm_mux[i]) { 3325 gsm_mux[i] = gsm; 3326 gsm->num = i; 3327 break; 3328 } 3329 } 3330 spin_unlock(&gsm_mux_lock); 3331 if (i == MAX_MUX) { 3332 mutex_destroy(&gsm->mutex); 3333 kfree(gsm->txframe); 3334 kfree(gsm->buf); 3335 kfree(gsm); 3336 return NULL; 3337 } 3338 3339 return gsm; 3340 } 3341 3342 static void gsm_copy_config_values(struct gsm_mux *gsm, 3343 struct gsm_config *c) 3344 { 3345 memset(c, 0, sizeof(*c)); 3346 c->adaption = gsm->adaption; 3347 c->encapsulation = gsm->encoding; 3348 c->initiator = gsm->initiator; 3349 c->t1 = gsm->t1; 3350 c->t2 = gsm->t2; 3351 c->t3 = gsm->t3; 3352 c->n2 = gsm->n2; 3353 if (gsm->ftype == UIH) 3354 c->i = 1; 3355 else 3356 c->i = 2; 3357 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i); 3358 c->mru = gsm->mru; 3359 c->mtu = gsm->mtu; 3360 c->k = gsm->k; 3361 } 3362 3363 static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c) 3364 { 3365 int need_close = 0; 3366 int need_restart = 0; 3367 3368 /* Stuff we don't support yet - UI or I frame transport */ 3369 if (c->adaption != 1 && c->adaption != 2) 3370 return -EOPNOTSUPP; 3371 /* Check the MRU/MTU range looks sane */ 3372 if (c->mru < MIN_MTU || c->mtu < MIN_MTU) 3373 return -EINVAL; 3374 if (c->mru > MAX_MRU || c->mtu > MAX_MTU) 3375 return -EINVAL; 3376 if (c->t3 > MAX_T3) 3377 return -EINVAL; 3378 if (c->n2 > 255) 3379 return -EINVAL; 3380 if (c->encapsulation > 1) /* Basic, advanced, no I */ 3381 return -EINVAL; 3382 if (c->initiator > 1) 3383 return -EINVAL; 3384 if (c->k > MAX_WINDOW_SIZE) 3385 return -EINVAL; 3386 if (c->i == 0 || c->i > 2) /* UIH and UI only */ 3387 return -EINVAL; 3388 /* 3389 * See what is needed for reconfiguration 3390 */ 3391 3392 /* Timing fields */ 3393 if (c->t1 != 0 && c->t1 != gsm->t1) 3394 need_restart = 1; 3395 if (c->t2 != 0 && c->t2 != gsm->t2) 3396 need_restart = 1; 3397 if (c->encapsulation != gsm->encoding) 3398 need_restart = 1; 3399 if (c->adaption != gsm->adaption) 3400 need_restart = 1; 3401 /* Requires care */ 3402 if (c->initiator != gsm->initiator) 3403 need_close = 1; 3404 if (c->mru != gsm->mru) 3405 need_restart = 1; 3406 if (c->mtu != gsm->mtu) 3407 need_restart = 1; 3408 3409 /* 3410 * Close down what is needed, restart and initiate the new 3411 * configuration. On the first time there is no DLCI[0] 3412 * and closing or cleaning up is not necessary. 3413 */ 3414 if (need_close || need_restart) 3415 gsm_cleanup_mux(gsm, true); 3416 3417 gsm->initiator = c->initiator; 3418 gsm->mru = c->mru; 3419 gsm->mtu = c->mtu; 3420 gsm->encoding = c->encapsulation ? GSM_ADV_OPT : GSM_BASIC_OPT; 3421 gsm->adaption = c->adaption; 3422 gsm->n2 = c->n2; 3423 3424 if (c->i == 1) 3425 gsm->ftype = UIH; 3426 else if (c->i == 2) 3427 gsm->ftype = UI; 3428 3429 if (c->t1) 3430 gsm->t1 = c->t1; 3431 if (c->t2) 3432 gsm->t2 = c->t2; 3433 if (c->t3) 3434 gsm->t3 = c->t3; 3435 if (c->k) 3436 gsm->k = c->k; 3437 3438 /* 3439 * FIXME: We need to separate activation/deactivation from adding 3440 * and removing from the mux array 3441 */ 3442 if (gsm->dead) { 3443 int ret = gsm_activate_mux(gsm); 3444 if (ret) 3445 return ret; 3446 if (gsm->initiator) 3447 gsm_dlci_begin_open(gsm->dlci[0]); 3448 } 3449 return 0; 3450 } 3451 3452 static void gsm_copy_config_ext_values(struct gsm_mux *gsm, 3453 struct gsm_config_ext *ce) 3454 { 3455 memset(ce, 0, sizeof(*ce)); 3456 ce->wait_config = gsm->wait_config ? 1 : 0; 3457 ce->keep_alive = gsm->keep_alive; 3458 } 3459 3460 static int gsm_config_ext(struct gsm_mux *gsm, struct gsm_config_ext *ce) 3461 { 3462 bool need_restart = false; 3463 unsigned int i; 3464 3465 /* 3466 * Check that userspace doesn't put stuff in here to prevent breakages 3467 * in the future. 3468 */ 3469 for (i = 0; i < ARRAY_SIZE(ce->reserved); i++) 3470 if (ce->reserved[i]) 3471 return -EINVAL; 3472 if (ce->flags & ~GSM_FL_RESTART) 3473 return -EINVAL; 3474 3475 /* Requires care */ 3476 if (ce->flags & GSM_FL_RESTART) 3477 need_restart = true; 3478 3479 /* 3480 * Close down what is needed, restart and initiate the new 3481 * configuration. On the first time there is no DLCI[0] 3482 * and closing or cleaning up is not necessary. 3483 */ 3484 if (need_restart) 3485 gsm_cleanup_mux(gsm, true); 3486 3487 /* 3488 * Setup the new configuration values 3489 */ 3490 gsm->wait_config = ce->wait_config ? true : false; 3491 gsm->keep_alive = ce->keep_alive; 3492 3493 if (gsm->dead) { 3494 int ret = gsm_activate_mux(gsm); 3495 if (ret) 3496 return ret; 3497 if (gsm->initiator) 3498 gsm_dlci_begin_open(gsm->dlci[0]); 3499 } 3500 3501 return 0; 3502 } 3503 3504 /** 3505 * gsmld_output - write to link 3506 * @gsm: our mux 3507 * @data: bytes to output 3508 * @len: size 3509 * 3510 * Write a block of data from the GSM mux to the data channel. This 3511 * will eventually be serialized from above but at the moment isn't. 3512 */ 3513 3514 static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len) 3515 { 3516 if (tty_write_room(gsm->tty) < len) { 3517 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags); 3518 return -ENOSPC; 3519 } 3520 if (debug & DBG_DATA) 3521 gsm_hex_dump_bytes(__func__, data, len); 3522 return gsm->tty->ops->write(gsm->tty, data, len); 3523 } 3524 3525 3526 /** 3527 * gsmld_write_trigger - schedule ldisc write task 3528 * @gsm: our mux 3529 */ 3530 static void gsmld_write_trigger(struct gsm_mux *gsm) 3531 { 3532 if (!gsm || !gsm->dlci[0] || gsm->dlci[0]->dead) 3533 return; 3534 schedule_work(&gsm->tx_work); 3535 } 3536 3537 3538 /** 3539 * gsmld_write_task - ldisc write task 3540 * @work: our tx write work 3541 * 3542 * Writes out data to the ldisc if possible. We are doing this here to 3543 * avoid dead-locking. This returns if no space or data is left for output. 3544 */ 3545 static void gsmld_write_task(struct work_struct *work) 3546 { 3547 struct gsm_mux *gsm = container_of(work, struct gsm_mux, tx_work); 3548 unsigned long flags; 3549 int i, ret; 3550 3551 /* All outstanding control channel and control messages and one data 3552 * frame is sent. 3553 */ 3554 ret = -ENODEV; 3555 spin_lock_irqsave(&gsm->tx_lock, flags); 3556 if (gsm->tty) 3557 ret = gsm_data_kick(gsm); 3558 spin_unlock_irqrestore(&gsm->tx_lock, flags); 3559 3560 if (ret >= 0) 3561 for (i = 0; i < NUM_DLCI; i++) 3562 if (gsm->dlci[i]) 3563 tty_port_tty_wakeup(&gsm->dlci[i]->port); 3564 } 3565 3566 /** 3567 * gsmld_attach_gsm - mode set up 3568 * @tty: our tty structure 3569 * @gsm: our mux 3570 * 3571 * Set up the MUX for basic mode and commence connecting to the 3572 * modem. Currently called from the line discipline set up but 3573 * will need moving to an ioctl path. 3574 */ 3575 3576 static void gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 3577 { 3578 gsm->tty = tty_kref_get(tty); 3579 /* Turn off tty XON/XOFF handling to handle it explicitly. */ 3580 gsm->old_c_iflag = tty->termios.c_iflag; 3581 tty->termios.c_iflag &= (IXON | IXOFF); 3582 } 3583 3584 /** 3585 * gsmld_detach_gsm - stop doing 0710 mux 3586 * @tty: tty attached to the mux 3587 * @gsm: mux 3588 * 3589 * Shutdown and then clean up the resources used by the line discipline 3590 */ 3591 3592 static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 3593 { 3594 WARN_ON(tty != gsm->tty); 3595 /* Restore tty XON/XOFF handling. */ 3596 gsm->tty->termios.c_iflag = gsm->old_c_iflag; 3597 tty_kref_put(gsm->tty); 3598 gsm->tty = NULL; 3599 } 3600 3601 static void gsmld_receive_buf(struct tty_struct *tty, const u8 *cp, 3602 const u8 *fp, size_t count) 3603 { 3604 struct gsm_mux *gsm = tty->disc_data; 3605 u8 flags = TTY_NORMAL; 3606 3607 if (debug & DBG_DATA) 3608 gsm_hex_dump_bytes(__func__, cp, count); 3609 3610 for (; count; count--, cp++) { 3611 if (fp) 3612 flags = *fp++; 3613 switch (flags) { 3614 case TTY_NORMAL: 3615 if (gsm->receive) 3616 gsm->receive(gsm, *cp); 3617 break; 3618 case TTY_OVERRUN: 3619 case TTY_BREAK: 3620 case TTY_PARITY: 3621 case TTY_FRAME: 3622 gsm_error(gsm); 3623 break; 3624 default: 3625 WARN_ONCE(1, "%s: unknown flag %d\n", 3626 tty_name(tty), flags); 3627 break; 3628 } 3629 } 3630 /* FASYNC if needed ? */ 3631 /* If clogged call tty_throttle(tty); */ 3632 } 3633 3634 /** 3635 * gsmld_flush_buffer - clean input queue 3636 * @tty: terminal device 3637 * 3638 * Flush the input buffer. Called when the line discipline is 3639 * being closed, when the tty layer wants the buffer flushed (eg 3640 * at hangup). 3641 */ 3642 3643 static void gsmld_flush_buffer(struct tty_struct *tty) 3644 { 3645 } 3646 3647 /** 3648 * gsmld_close - close the ldisc for this tty 3649 * @tty: device 3650 * 3651 * Called from the terminal layer when this line discipline is 3652 * being shut down, either because of a close or becsuse of a 3653 * discipline change. The function will not be called while other 3654 * ldisc methods are in progress. 3655 */ 3656 3657 static void gsmld_close(struct tty_struct *tty) 3658 { 3659 struct gsm_mux *gsm = tty->disc_data; 3660 3661 /* The ldisc locks and closes the port before calling our close. This 3662 * means we have no way to do a proper disconnect. We will not bother 3663 * to do one. 3664 */ 3665 gsm_cleanup_mux(gsm, false); 3666 3667 gsmld_detach_gsm(tty, gsm); 3668 3669 gsmld_flush_buffer(tty); 3670 /* Do other clean up here */ 3671 mux_put(gsm); 3672 } 3673 3674 /** 3675 * gsmld_open - open an ldisc 3676 * @tty: terminal to open 3677 * 3678 * Called when this line discipline is being attached to the 3679 * terminal device. Can sleep. Called serialized so that no 3680 * other events will occur in parallel. No further open will occur 3681 * until a close. 3682 */ 3683 3684 static int gsmld_open(struct tty_struct *tty) 3685 { 3686 struct gsm_mux *gsm; 3687 3688 if (!capable(CAP_NET_ADMIN)) 3689 return -EPERM; 3690 3691 if (tty->ops->write == NULL) 3692 return -EINVAL; 3693 3694 /* Attach our ldisc data */ 3695 gsm = gsm_alloc_mux(); 3696 if (gsm == NULL) 3697 return -ENOMEM; 3698 3699 tty->disc_data = gsm; 3700 tty->receive_room = 65536; 3701 3702 /* Attach the initial passive connection */ 3703 gsmld_attach_gsm(tty, gsm); 3704 3705 /* The mux will not be activated yet, we wait for correct 3706 * configuration first. 3707 */ 3708 if (gsm->encoding == GSM_BASIC_OPT) 3709 gsm->receive = gsm0_receive; 3710 else 3711 gsm->receive = gsm1_receive; 3712 3713 return 0; 3714 } 3715 3716 /** 3717 * gsmld_write_wakeup - asynchronous I/O notifier 3718 * @tty: tty device 3719 * 3720 * Required for the ptys, serial driver etc. since processes 3721 * that attach themselves to the master and rely on ASYNC 3722 * IO must be woken up 3723 */ 3724 3725 static void gsmld_write_wakeup(struct tty_struct *tty) 3726 { 3727 struct gsm_mux *gsm = tty->disc_data; 3728 3729 /* Queue poll */ 3730 gsmld_write_trigger(gsm); 3731 } 3732 3733 /** 3734 * gsmld_read - read function for tty 3735 * @tty: tty device 3736 * @file: file object 3737 * @buf: userspace buffer pointer 3738 * @nr: size of I/O 3739 * @cookie: unused 3740 * @offset: unused 3741 * 3742 * Perform reads for the line discipline. We are guaranteed that the 3743 * line discipline will not be closed under us but we may get multiple 3744 * parallel readers and must handle this ourselves. We may also get 3745 * a hangup. Always called in user context, may sleep. 3746 * 3747 * This code must be sure never to sleep through a hangup. 3748 */ 3749 3750 static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, u8 *buf, 3751 size_t nr, void **cookie, unsigned long offset) 3752 { 3753 return -EOPNOTSUPP; 3754 } 3755 3756 /** 3757 * gsmld_write - write function for tty 3758 * @tty: tty device 3759 * @file: file object 3760 * @buf: userspace buffer pointer 3761 * @nr: size of I/O 3762 * 3763 * Called when the owner of the device wants to send a frame 3764 * itself (or some other control data). The data is transferred 3765 * as-is and must be properly framed and checksummed as appropriate 3766 * by userspace. Frames are either sent whole or not at all as this 3767 * avoids pain user side. 3768 */ 3769 3770 static ssize_t gsmld_write(struct tty_struct *tty, struct file *file, 3771 const u8 *buf, size_t nr) 3772 { 3773 struct gsm_mux *gsm = tty->disc_data; 3774 unsigned long flags; 3775 size_t space; 3776 int ret; 3777 3778 if (!gsm) 3779 return -ENODEV; 3780 3781 ret = -ENOBUFS; 3782 spin_lock_irqsave(&gsm->tx_lock, flags); 3783 space = tty_write_room(tty); 3784 if (space >= nr) 3785 ret = tty->ops->write(tty, buf, nr); 3786 else 3787 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 3788 spin_unlock_irqrestore(&gsm->tx_lock, flags); 3789 3790 return ret; 3791 } 3792 3793 /** 3794 * gsmld_poll - poll method for N_GSM0710 3795 * @tty: terminal device 3796 * @file: file accessing it 3797 * @wait: poll table 3798 * 3799 * Called when the line discipline is asked to poll() for data or 3800 * for special events. This code is not serialized with respect to 3801 * other events save open/close. 3802 * 3803 * This code must be sure never to sleep through a hangup. 3804 * Called without the kernel lock held - fine 3805 */ 3806 3807 static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file, 3808 poll_table *wait) 3809 { 3810 __poll_t mask = 0; 3811 struct gsm_mux *gsm = tty->disc_data; 3812 3813 poll_wait(file, &tty->read_wait, wait); 3814 poll_wait(file, &tty->write_wait, wait); 3815 3816 if (gsm->dead) 3817 mask |= EPOLLHUP; 3818 if (tty_hung_up_p(file)) 3819 mask |= EPOLLHUP; 3820 if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) 3821 mask |= EPOLLHUP; 3822 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0) 3823 mask |= EPOLLOUT | EPOLLWRNORM; 3824 return mask; 3825 } 3826 3827 static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd, 3828 unsigned long arg) 3829 { 3830 struct gsm_config c; 3831 struct gsm_config_ext ce; 3832 struct gsm_dlci_config dc; 3833 struct gsm_mux *gsm = tty->disc_data; 3834 unsigned int base, addr; 3835 struct gsm_dlci *dlci; 3836 3837 switch (cmd) { 3838 case GSMIOC_GETCONF: 3839 gsm_copy_config_values(gsm, &c); 3840 if (copy_to_user((void __user *)arg, &c, sizeof(c))) 3841 return -EFAULT; 3842 return 0; 3843 case GSMIOC_SETCONF: 3844 if (copy_from_user(&c, (void __user *)arg, sizeof(c))) 3845 return -EFAULT; 3846 return gsm_config(gsm, &c); 3847 case GSMIOC_GETFIRST: 3848 base = mux_num_to_base(gsm); 3849 return put_user(base + 1, (__u32 __user *)arg); 3850 case GSMIOC_GETCONF_EXT: 3851 gsm_copy_config_ext_values(gsm, &ce); 3852 if (copy_to_user((void __user *)arg, &ce, sizeof(ce))) 3853 return -EFAULT; 3854 return 0; 3855 case GSMIOC_SETCONF_EXT: 3856 if (copy_from_user(&ce, (void __user *)arg, sizeof(ce))) 3857 return -EFAULT; 3858 return gsm_config_ext(gsm, &ce); 3859 case GSMIOC_GETCONF_DLCI: 3860 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc))) 3861 return -EFAULT; 3862 if (dc.channel == 0 || dc.channel >= NUM_DLCI) 3863 return -EINVAL; 3864 addr = array_index_nospec(dc.channel, NUM_DLCI); 3865 dlci = gsm->dlci[addr]; 3866 if (!dlci) { 3867 dlci = gsm_dlci_alloc(gsm, addr); 3868 if (!dlci) 3869 return -ENOMEM; 3870 } 3871 gsm_dlci_copy_config_values(dlci, &dc); 3872 if (copy_to_user((void __user *)arg, &dc, sizeof(dc))) 3873 return -EFAULT; 3874 return 0; 3875 case GSMIOC_SETCONF_DLCI: 3876 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc))) 3877 return -EFAULT; 3878 if (dc.channel == 0 || dc.channel >= NUM_DLCI) 3879 return -EINVAL; 3880 addr = array_index_nospec(dc.channel, NUM_DLCI); 3881 dlci = gsm->dlci[addr]; 3882 if (!dlci) { 3883 dlci = gsm_dlci_alloc(gsm, addr); 3884 if (!dlci) 3885 return -ENOMEM; 3886 } 3887 return gsm_dlci_config(dlci, &dc, 0); 3888 default: 3889 return n_tty_ioctl_helper(tty, cmd, arg); 3890 } 3891 } 3892 3893 /* 3894 * Network interface 3895 * 3896 */ 3897 3898 static int gsm_mux_net_open(struct net_device *net) 3899 { 3900 pr_debug("%s called\n", __func__); 3901 netif_start_queue(net); 3902 return 0; 3903 } 3904 3905 static int gsm_mux_net_close(struct net_device *net) 3906 { 3907 netif_stop_queue(net); 3908 return 0; 3909 } 3910 3911 static void dlci_net_free(struct gsm_dlci *dlci) 3912 { 3913 if (!dlci->net) { 3914 WARN_ON(1); 3915 return; 3916 } 3917 dlci->adaption = dlci->prev_adaption; 3918 dlci->data = dlci->prev_data; 3919 free_netdev(dlci->net); 3920 dlci->net = NULL; 3921 } 3922 static void net_free(struct kref *ref) 3923 { 3924 struct gsm_mux_net *mux_net; 3925 struct gsm_dlci *dlci; 3926 3927 mux_net = container_of(ref, struct gsm_mux_net, ref); 3928 dlci = mux_net->dlci; 3929 3930 if (dlci->net) { 3931 unregister_netdev(dlci->net); 3932 dlci_net_free(dlci); 3933 } 3934 } 3935 3936 static inline void muxnet_get(struct gsm_mux_net *mux_net) 3937 { 3938 kref_get(&mux_net->ref); 3939 } 3940 3941 static inline void muxnet_put(struct gsm_mux_net *mux_net) 3942 { 3943 kref_put(&mux_net->ref, net_free); 3944 } 3945 3946 static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb, 3947 struct net_device *net) 3948 { 3949 struct gsm_mux_net *mux_net = netdev_priv(net); 3950 struct gsm_dlci *dlci = mux_net->dlci; 3951 muxnet_get(mux_net); 3952 3953 skb_queue_head(&dlci->skb_list, skb); 3954 net->stats.tx_packets++; 3955 net->stats.tx_bytes += skb->len; 3956 gsm_dlci_data_kick(dlci); 3957 /* And tell the kernel when the last transmit started. */ 3958 netif_trans_update(net); 3959 muxnet_put(mux_net); 3960 return NETDEV_TX_OK; 3961 } 3962 3963 /* called when a packet did not ack after watchdogtimeout */ 3964 static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue) 3965 { 3966 /* Tell syslog we are hosed. */ 3967 dev_dbg(&net->dev, "Tx timed out.\n"); 3968 3969 /* Update statistics */ 3970 net->stats.tx_errors++; 3971 } 3972 3973 static void gsm_mux_rx_netchar(struct gsm_dlci *dlci, const u8 *in_buf, int size) 3974 { 3975 struct net_device *net = dlci->net; 3976 struct sk_buff *skb; 3977 struct gsm_mux_net *mux_net = netdev_priv(net); 3978 muxnet_get(mux_net); 3979 3980 /* Allocate an sk_buff */ 3981 skb = dev_alloc_skb(size + NET_IP_ALIGN); 3982 if (!skb) { 3983 /* We got no receive buffer. */ 3984 net->stats.rx_dropped++; 3985 muxnet_put(mux_net); 3986 return; 3987 } 3988 skb_reserve(skb, NET_IP_ALIGN); 3989 skb_put_data(skb, in_buf, size); 3990 3991 skb->dev = net; 3992 skb->protocol = htons(ETH_P_IP); 3993 3994 /* Ship it off to the kernel */ 3995 netif_rx(skb); 3996 3997 /* update out statistics */ 3998 net->stats.rx_packets++; 3999 net->stats.rx_bytes += size; 4000 muxnet_put(mux_net); 4001 return; 4002 } 4003 4004 static void gsm_mux_net_init(struct net_device *net) 4005 { 4006 static const struct net_device_ops gsm_netdev_ops = { 4007 .ndo_open = gsm_mux_net_open, 4008 .ndo_stop = gsm_mux_net_close, 4009 .ndo_start_xmit = gsm_mux_net_start_xmit, 4010 .ndo_tx_timeout = gsm_mux_net_tx_timeout, 4011 }; 4012 4013 net->netdev_ops = &gsm_netdev_ops; 4014 4015 /* fill in the other fields */ 4016 net->watchdog_timeo = GSM_NET_TX_TIMEOUT; 4017 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 4018 net->type = ARPHRD_NONE; 4019 net->tx_queue_len = 10; 4020 } 4021 4022 4023 /* caller holds the dlci mutex */ 4024 static void gsm_destroy_network(struct gsm_dlci *dlci) 4025 { 4026 struct gsm_mux_net *mux_net; 4027 4028 pr_debug("destroy network interface\n"); 4029 if (!dlci->net) 4030 return; 4031 mux_net = netdev_priv(dlci->net); 4032 muxnet_put(mux_net); 4033 } 4034 4035 4036 /* caller holds the dlci mutex */ 4037 static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc) 4038 { 4039 char *netname; 4040 int retval = 0; 4041 struct net_device *net; 4042 struct gsm_mux_net *mux_net; 4043 4044 if (!capable(CAP_NET_ADMIN)) 4045 return -EPERM; 4046 4047 /* Already in a non tty mode */ 4048 if (dlci->adaption > 2) 4049 return -EBUSY; 4050 4051 if (nc->protocol != htons(ETH_P_IP)) 4052 return -EPROTONOSUPPORT; 4053 4054 if (nc->adaption != 3 && nc->adaption != 4) 4055 return -EPROTONOSUPPORT; 4056 4057 pr_debug("create network interface\n"); 4058 4059 netname = "gsm%d"; 4060 if (nc->if_name[0] != '\0') 4061 netname = nc->if_name; 4062 net = alloc_netdev(sizeof(struct gsm_mux_net), netname, 4063 NET_NAME_UNKNOWN, gsm_mux_net_init); 4064 if (!net) { 4065 pr_err("alloc_netdev failed\n"); 4066 return -ENOMEM; 4067 } 4068 net->mtu = dlci->mtu; 4069 net->min_mtu = MIN_MTU; 4070 net->max_mtu = dlci->mtu; 4071 mux_net = netdev_priv(net); 4072 mux_net->dlci = dlci; 4073 kref_init(&mux_net->ref); 4074 strscpy(nc->if_name, net->name); /* return net name */ 4075 4076 /* reconfigure dlci for network */ 4077 dlci->prev_adaption = dlci->adaption; 4078 dlci->prev_data = dlci->data; 4079 dlci->adaption = nc->adaption; 4080 dlci->data = gsm_mux_rx_netchar; 4081 dlci->net = net; 4082 4083 pr_debug("register netdev\n"); 4084 retval = register_netdev(net); 4085 if (retval) { 4086 pr_err("network register fail %d\n", retval); 4087 dlci_net_free(dlci); 4088 return retval; 4089 } 4090 return net->ifindex; /* return network index */ 4091 } 4092 4093 /* Line discipline for real tty */ 4094 static struct tty_ldisc_ops tty_ldisc_packet = { 4095 .owner = THIS_MODULE, 4096 .num = N_GSM0710, 4097 .name = "n_gsm", 4098 .open = gsmld_open, 4099 .close = gsmld_close, 4100 .flush_buffer = gsmld_flush_buffer, 4101 .read = gsmld_read, 4102 .write = gsmld_write, 4103 .ioctl = gsmld_ioctl, 4104 .poll = gsmld_poll, 4105 .receive_buf = gsmld_receive_buf, 4106 .write_wakeup = gsmld_write_wakeup 4107 }; 4108 4109 /* 4110 * Virtual tty side 4111 */ 4112 4113 /** 4114 * gsm_modem_upd_via_data - send modem bits via convergence layer 4115 * @dlci: channel 4116 * @brk: break signal 4117 * 4118 * Send an empty frame to signal mobile state changes and to transmit the 4119 * break signal for adaption 2. 4120 */ 4121 4122 static void gsm_modem_upd_via_data(struct gsm_dlci *dlci, u8 brk) 4123 { 4124 struct gsm_mux *gsm = dlci->gsm; 4125 unsigned long flags; 4126 4127 if (dlci->state != DLCI_OPEN || dlci->adaption != 2) 4128 return; 4129 4130 spin_lock_irqsave(&gsm->tx_lock, flags); 4131 gsm_dlci_modem_output(gsm, dlci, brk); 4132 spin_unlock_irqrestore(&gsm->tx_lock, flags); 4133 } 4134 4135 /** 4136 * gsm_modem_upd_via_msc - send modem bits via control frame 4137 * @dlci: channel 4138 * @brk: break signal 4139 */ 4140 4141 static int gsm_modem_upd_via_msc(struct gsm_dlci *dlci, u8 brk) 4142 { 4143 u8 modembits[3]; 4144 struct gsm_control *ctrl; 4145 int len = 2; 4146 4147 if (dlci->gsm->encoding != GSM_BASIC_OPT) 4148 return 0; 4149 4150 modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */ 4151 if (!brk) { 4152 modembits[1] = (gsm_encode_modem(dlci) << 1) | EA; 4153 } else { 4154 modembits[1] = gsm_encode_modem(dlci) << 1; 4155 modembits[2] = (brk << 4) | 2 | EA; /* Length, Break, EA */ 4156 len++; 4157 } 4158 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len); 4159 if (ctrl == NULL) 4160 return -ENOMEM; 4161 return gsm_control_wait(dlci->gsm, ctrl); 4162 } 4163 4164 /** 4165 * gsm_modem_update - send modem status line state 4166 * @dlci: channel 4167 * @brk: break signal 4168 */ 4169 4170 static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk) 4171 { 4172 if (dlci->gsm->dead) 4173 return -EL2HLT; 4174 if (dlci->adaption == 2) { 4175 /* Send convergence layer type 2 empty data frame. */ 4176 gsm_modem_upd_via_data(dlci, brk); 4177 return 0; 4178 } else if (dlci->gsm->encoding == GSM_BASIC_OPT) { 4179 /* Send as MSC control message. */ 4180 return gsm_modem_upd_via_msc(dlci, brk); 4181 } 4182 4183 /* Modem status lines are not supported. */ 4184 return -EPROTONOSUPPORT; 4185 } 4186 4187 /** 4188 * gsm_wait_modem_change - wait for modem status line change 4189 * @dlci: channel 4190 * @mask: modem status line bits 4191 * 4192 * The function returns if: 4193 * - any given modem status line bit changed 4194 * - the wait event function got interrupted (e.g. by a signal) 4195 * - the underlying DLCI was closed 4196 * - the underlying ldisc device was removed 4197 */ 4198 static int gsm_wait_modem_change(struct gsm_dlci *dlci, u32 mask) 4199 { 4200 struct gsm_mux *gsm = dlci->gsm; 4201 u32 old = dlci->modem_rx; 4202 int ret; 4203 4204 ret = wait_event_interruptible(gsm->event, gsm->dead || 4205 dlci->state != DLCI_OPEN || 4206 (old ^ dlci->modem_rx) & mask); 4207 if (gsm->dead) 4208 return -ENODEV; 4209 if (dlci->state != DLCI_OPEN) 4210 return -EL2NSYNC; 4211 return ret; 4212 } 4213 4214 static bool gsm_carrier_raised(struct tty_port *port) 4215 { 4216 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 4217 struct gsm_mux *gsm = dlci->gsm; 4218 4219 /* Not yet open so no carrier info */ 4220 if (dlci->state != DLCI_OPEN) 4221 return false; 4222 if (debug & DBG_CD_ON) 4223 return true; 4224 4225 /* 4226 * Basic mode with control channel in ADM mode may not respond 4227 * to CMD_MSC at all and modem_rx is empty. 4228 */ 4229 if (gsm->encoding == GSM_BASIC_OPT && 4230 gsm->dlci[0]->mode == DLCI_MODE_ADM && !dlci->modem_rx) 4231 return true; 4232 4233 return dlci->modem_rx & TIOCM_CD; 4234 } 4235 4236 static void gsm_dtr_rts(struct tty_port *port, bool active) 4237 { 4238 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 4239 unsigned int modem_tx = dlci->modem_tx; 4240 if (active) 4241 modem_tx |= TIOCM_DTR | TIOCM_RTS; 4242 else 4243 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); 4244 if (modem_tx != dlci->modem_tx) { 4245 dlci->modem_tx = modem_tx; 4246 gsm_modem_update(dlci, 0); 4247 } 4248 } 4249 4250 static const struct tty_port_operations gsm_port_ops = { 4251 .carrier_raised = gsm_carrier_raised, 4252 .dtr_rts = gsm_dtr_rts, 4253 .destruct = gsm_dlci_free, 4254 }; 4255 4256 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty) 4257 { 4258 struct gsm_mux *gsm; 4259 struct gsm_dlci *dlci, *dlci0; 4260 unsigned int line = tty->index; 4261 unsigned int mux = mux_line_to_num(line); 4262 bool alloc = false; 4263 int ret; 4264 4265 line = line & 0x3F; 4266 4267 if (mux >= MAX_MUX) 4268 return -ENXIO; 4269 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */ 4270 if (gsm_mux[mux] == NULL) 4271 return -EUNATCH; 4272 if (line == 0 || line > 61) /* 62/63 reserved */ 4273 return -ECHRNG; 4274 gsm = gsm_mux[mux]; 4275 if (gsm->dead) 4276 return -EL2HLT; 4277 /* If DLCI 0 is not yet fully open return an error. 4278 This is ok from a locking 4279 perspective as we don't have to worry about this 4280 if DLCI0 is lost */ 4281 mutex_lock(&gsm->mutex); 4282 4283 dlci0 = gsm->dlci[0]; 4284 if (dlci0 && dlci0->state != DLCI_OPEN) { 4285 mutex_unlock(&gsm->mutex); 4286 4287 if (dlci0->state == DLCI_OPENING) 4288 wait_event(gsm->event, dlci0->state != DLCI_OPENING); 4289 4290 if (dlci0->state != DLCI_OPEN) 4291 return -EL2NSYNC; 4292 4293 mutex_lock(&gsm->mutex); 4294 } 4295 4296 dlci = gsm->dlci[line]; 4297 if (dlci == NULL) { 4298 alloc = true; 4299 dlci = gsm_dlci_alloc(gsm, line); 4300 } 4301 if (dlci == NULL) { 4302 mutex_unlock(&gsm->mutex); 4303 return -ENOMEM; 4304 } 4305 ret = tty_port_install(&dlci->port, driver, tty); 4306 if (ret) { 4307 if (alloc) 4308 dlci_put(dlci); 4309 mutex_unlock(&gsm->mutex); 4310 return ret; 4311 } 4312 4313 dlci_get(dlci); 4314 dlci_get(gsm->dlci[0]); 4315 mux_get(gsm); 4316 tty->driver_data = dlci; 4317 mutex_unlock(&gsm->mutex); 4318 4319 return 0; 4320 } 4321 4322 static int gsmtty_open(struct tty_struct *tty, struct file *filp) 4323 { 4324 struct gsm_dlci *dlci = tty->driver_data; 4325 struct tty_port *port = &dlci->port; 4326 4327 port->count++; 4328 tty_port_tty_set(port, tty); 4329 4330 dlci->modem_rx = 0; 4331 /* We could in theory open and close before we wait - eg if we get 4332 a DM straight back. This is ok as that will have caused a hangup */ 4333 tty_port_set_initialized(port, true); 4334 /* Start sending off SABM messages */ 4335 if (!dlci->gsm->wait_config) { 4336 /* Start sending off SABM messages */ 4337 if (dlci->gsm->initiator) 4338 gsm_dlci_begin_open(dlci); 4339 else 4340 gsm_dlci_set_opening(dlci); 4341 } else { 4342 gsm_dlci_set_wait_config(dlci); 4343 } 4344 /* And wait for virtual carrier */ 4345 return tty_port_block_til_ready(port, tty, filp); 4346 } 4347 4348 static void gsmtty_close(struct tty_struct *tty, struct file *filp) 4349 { 4350 struct gsm_dlci *dlci = tty->driver_data; 4351 4352 if (dlci == NULL) 4353 return; 4354 if (dlci->state == DLCI_CLOSED) 4355 return; 4356 mutex_lock(&dlci->mutex); 4357 gsm_destroy_network(dlci); 4358 mutex_unlock(&dlci->mutex); 4359 if (tty_port_close_start(&dlci->port, tty, filp) == 0) 4360 return; 4361 gsm_dlci_begin_close(dlci); 4362 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty)) 4363 tty_port_lower_dtr_rts(&dlci->port); 4364 tty_port_close_end(&dlci->port, tty); 4365 tty_port_tty_set(&dlci->port, NULL); 4366 return; 4367 } 4368 4369 static void gsmtty_hangup(struct tty_struct *tty) 4370 { 4371 struct gsm_dlci *dlci = tty->driver_data; 4372 if (dlci->state == DLCI_CLOSED) 4373 return; 4374 tty_port_hangup(&dlci->port); 4375 gsm_dlci_begin_close(dlci); 4376 } 4377 4378 static ssize_t gsmtty_write(struct tty_struct *tty, const u8 *buf, size_t len) 4379 { 4380 int sent; 4381 struct gsm_dlci *dlci = tty->driver_data; 4382 if (dlci->state == DLCI_CLOSED) 4383 return -EINVAL; 4384 /* Stuff the bytes into the fifo queue */ 4385 sent = kfifo_in_locked(&dlci->fifo, buf, len, &dlci->lock); 4386 /* Need to kick the channel */ 4387 gsm_dlci_data_kick(dlci); 4388 return sent; 4389 } 4390 4391 static unsigned int gsmtty_write_room(struct tty_struct *tty) 4392 { 4393 struct gsm_dlci *dlci = tty->driver_data; 4394 if (dlci->state == DLCI_CLOSED) 4395 return 0; 4396 return kfifo_avail(&dlci->fifo); 4397 } 4398 4399 static unsigned int gsmtty_chars_in_buffer(struct tty_struct *tty) 4400 { 4401 struct gsm_dlci *dlci = tty->driver_data; 4402 if (dlci->state == DLCI_CLOSED) 4403 return 0; 4404 return kfifo_len(&dlci->fifo); 4405 } 4406 4407 static void gsmtty_flush_buffer(struct tty_struct *tty) 4408 { 4409 struct gsm_dlci *dlci = tty->driver_data; 4410 unsigned long flags; 4411 4412 if (dlci->state == DLCI_CLOSED) 4413 return; 4414 /* Caution needed: If we implement reliable transport classes 4415 then the data being transmitted can't simply be junked once 4416 it has first hit the stack. Until then we can just blow it 4417 away */ 4418 spin_lock_irqsave(&dlci->lock, flags); 4419 kfifo_reset(&dlci->fifo); 4420 spin_unlock_irqrestore(&dlci->lock, flags); 4421 /* Need to unhook this DLCI from the transmit queue logic */ 4422 } 4423 4424 static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout) 4425 { 4426 /* The FIFO handles the queue so the kernel will do the right 4427 thing waiting on chars_in_buffer before calling us. No work 4428 to do here */ 4429 } 4430 4431 static int gsmtty_tiocmget(struct tty_struct *tty) 4432 { 4433 struct gsm_dlci *dlci = tty->driver_data; 4434 if (dlci->state == DLCI_CLOSED) 4435 return -EINVAL; 4436 return dlci->modem_rx; 4437 } 4438 4439 static int gsmtty_tiocmset(struct tty_struct *tty, 4440 unsigned int set, unsigned int clear) 4441 { 4442 struct gsm_dlci *dlci = tty->driver_data; 4443 unsigned int modem_tx = dlci->modem_tx; 4444 4445 if (dlci->state == DLCI_CLOSED) 4446 return -EINVAL; 4447 modem_tx &= ~clear; 4448 modem_tx |= set; 4449 4450 if (modem_tx != dlci->modem_tx) { 4451 dlci->modem_tx = modem_tx; 4452 return gsm_modem_update(dlci, 0); 4453 } 4454 return 0; 4455 } 4456 4457 4458 static int gsmtty_ioctl(struct tty_struct *tty, 4459 unsigned int cmd, unsigned long arg) 4460 { 4461 struct gsm_dlci *dlci = tty->driver_data; 4462 struct gsm_netconfig nc; 4463 struct gsm_dlci_config dc; 4464 int index; 4465 4466 if (dlci->state == DLCI_CLOSED) 4467 return -EINVAL; 4468 switch (cmd) { 4469 case GSMIOC_ENABLE_NET: 4470 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc))) 4471 return -EFAULT; 4472 nc.if_name[IFNAMSIZ-1] = '\0'; 4473 /* return net interface index or error code */ 4474 mutex_lock(&dlci->mutex); 4475 index = gsm_create_network(dlci, &nc); 4476 mutex_unlock(&dlci->mutex); 4477 if (copy_to_user((void __user *)arg, &nc, sizeof(nc))) 4478 return -EFAULT; 4479 return index; 4480 case GSMIOC_DISABLE_NET: 4481 if (!capable(CAP_NET_ADMIN)) 4482 return -EPERM; 4483 mutex_lock(&dlci->mutex); 4484 gsm_destroy_network(dlci); 4485 mutex_unlock(&dlci->mutex); 4486 return 0; 4487 case GSMIOC_GETCONF_DLCI: 4488 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc))) 4489 return -EFAULT; 4490 if (dc.channel != dlci->addr) 4491 return -EPERM; 4492 gsm_dlci_copy_config_values(dlci, &dc); 4493 if (copy_to_user((void __user *)arg, &dc, sizeof(dc))) 4494 return -EFAULT; 4495 return 0; 4496 case GSMIOC_SETCONF_DLCI: 4497 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc))) 4498 return -EFAULT; 4499 if (dc.channel >= NUM_DLCI) 4500 return -EINVAL; 4501 if (dc.channel != 0 && dc.channel != dlci->addr) 4502 return -EPERM; 4503 return gsm_dlci_config(dlci, &dc, 1); 4504 case TIOCMIWAIT: 4505 return gsm_wait_modem_change(dlci, (u32)arg); 4506 default: 4507 return -ENOIOCTLCMD; 4508 } 4509 } 4510 4511 static void gsmtty_set_termios(struct tty_struct *tty, 4512 const struct ktermios *old) 4513 { 4514 struct gsm_dlci *dlci = tty->driver_data; 4515 if (dlci->state == DLCI_CLOSED) 4516 return; 4517 /* For the moment its fixed. In actual fact the speed information 4518 for the virtual channel can be propogated in both directions by 4519 the RPN control message. This however rapidly gets nasty as we 4520 then have to remap modem signals each way according to whether 4521 our virtual cable is null modem etc .. */ 4522 tty_termios_copy_hw(&tty->termios, old); 4523 } 4524 4525 static void gsmtty_throttle(struct tty_struct *tty) 4526 { 4527 struct gsm_dlci *dlci = tty->driver_data; 4528 if (dlci->state == DLCI_CLOSED) 4529 return; 4530 if (C_CRTSCTS(tty)) 4531 dlci->modem_tx &= ~TIOCM_RTS; 4532 dlci->throttled = true; 4533 /* Send an MSC with RTS cleared */ 4534 gsm_modem_update(dlci, 0); 4535 } 4536 4537 static void gsmtty_unthrottle(struct tty_struct *tty) 4538 { 4539 struct gsm_dlci *dlci = tty->driver_data; 4540 if (dlci->state == DLCI_CLOSED) 4541 return; 4542 if (C_CRTSCTS(tty)) 4543 dlci->modem_tx |= TIOCM_RTS; 4544 dlci->throttled = false; 4545 /* Send an MSC with RTS set */ 4546 gsm_modem_update(dlci, 0); 4547 } 4548 4549 static int gsmtty_break_ctl(struct tty_struct *tty, int state) 4550 { 4551 struct gsm_dlci *dlci = tty->driver_data; 4552 int encode = 0; /* Off */ 4553 if (dlci->state == DLCI_CLOSED) 4554 return -EINVAL; 4555 4556 if (state == -1) /* "On indefinitely" - we can't encode this 4557 properly */ 4558 encode = 0x0F; 4559 else if (state > 0) { 4560 encode = state / 200; /* mS to encoding */ 4561 if (encode > 0x0F) 4562 encode = 0x0F; /* Best effort */ 4563 } 4564 return gsm_modem_update(dlci, encode); 4565 } 4566 4567 static void gsmtty_cleanup(struct tty_struct *tty) 4568 { 4569 struct gsm_dlci *dlci = tty->driver_data; 4570 struct gsm_mux *gsm = dlci->gsm; 4571 4572 dlci_put(dlci); 4573 dlci_put(gsm->dlci[0]); 4574 mux_put(gsm); 4575 } 4576 4577 /* Virtual ttys for the demux */ 4578 static const struct tty_operations gsmtty_ops = { 4579 .install = gsmtty_install, 4580 .open = gsmtty_open, 4581 .close = gsmtty_close, 4582 .write = gsmtty_write, 4583 .write_room = gsmtty_write_room, 4584 .chars_in_buffer = gsmtty_chars_in_buffer, 4585 .flush_buffer = gsmtty_flush_buffer, 4586 .ioctl = gsmtty_ioctl, 4587 .throttle = gsmtty_throttle, 4588 .unthrottle = gsmtty_unthrottle, 4589 .set_termios = gsmtty_set_termios, 4590 .hangup = gsmtty_hangup, 4591 .wait_until_sent = gsmtty_wait_until_sent, 4592 .tiocmget = gsmtty_tiocmget, 4593 .tiocmset = gsmtty_tiocmset, 4594 .break_ctl = gsmtty_break_ctl, 4595 .cleanup = gsmtty_cleanup, 4596 }; 4597 4598 4599 4600 static int __init gsm_init(void) 4601 { 4602 /* Fill in our line protocol discipline, and register it */ 4603 int status = tty_register_ldisc(&tty_ldisc_packet); 4604 if (status != 0) { 4605 pr_err("n_gsm: can't register line discipline (err = %d)\n", 4606 status); 4607 return status; 4608 } 4609 4610 gsm_tty_driver = tty_alloc_driver(GSM_TTY_MINORS, TTY_DRIVER_REAL_RAW | 4611 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_HARDWARE_BREAK); 4612 if (IS_ERR(gsm_tty_driver)) { 4613 pr_err("gsm_init: tty allocation failed.\n"); 4614 status = PTR_ERR(gsm_tty_driver); 4615 goto err_unreg_ldisc; 4616 } 4617 gsm_tty_driver->driver_name = "gsmtty"; 4618 gsm_tty_driver->name = "gsmtty"; 4619 gsm_tty_driver->major = 0; /* Dynamic */ 4620 gsm_tty_driver->minor_start = 0; 4621 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; 4622 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL; 4623 gsm_tty_driver->init_termios = tty_std_termios; 4624 /* Fixme */ 4625 gsm_tty_driver->init_termios.c_lflag &= ~ECHO; 4626 tty_set_operations(gsm_tty_driver, &gsmtty_ops); 4627 4628 if (tty_register_driver(gsm_tty_driver)) { 4629 pr_err("gsm_init: tty registration failed.\n"); 4630 status = -EBUSY; 4631 goto err_put_driver; 4632 } 4633 pr_debug("gsm_init: loaded as %d,%d.\n", 4634 gsm_tty_driver->major, gsm_tty_driver->minor_start); 4635 return 0; 4636 err_put_driver: 4637 tty_driver_kref_put(gsm_tty_driver); 4638 err_unreg_ldisc: 4639 tty_unregister_ldisc(&tty_ldisc_packet); 4640 return status; 4641 } 4642 4643 static void __exit gsm_exit(void) 4644 { 4645 tty_unregister_ldisc(&tty_ldisc_packet); 4646 tty_unregister_driver(gsm_tty_driver); 4647 tty_driver_kref_put(gsm_tty_driver); 4648 } 4649 4650 module_init(gsm_init); 4651 module_exit(gsm_exit); 4652 4653 4654 MODULE_DESCRIPTION("GSM 0710 tty multiplexor"); 4655 MODULE_LICENSE("GPL"); 4656 MODULE_ALIAS_LDISC(N_GSM0710); 4657