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n_gsm.c
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linux-6.19.14/drivers/tty/n_gsm.c
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 --ยด 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 67static int debug; 68module_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 */ 111struct 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 122struct 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 131enum 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 140enum 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 155struct 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 197struct 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 207static_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 233struct 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 241enum gsm_encoding { 242 GSM_BASIC_OPT, 243 GSM_ADV_OPT, 244}; 245 246enum 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 272struct 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 */ 357static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */ 358static DEFINE_SPINLOCK(gsm_mux_lock); 359 360static 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 411static const struct tty_port_operations gsm_port_ops; 412 413/* 414 * CRC table for GSM 0710 415 */ 416 417static 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 455static void gsm_dlci_close(struct gsm_dlci *dlci); 456static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len); 457static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk); 458static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len, 459 u8 ctrl); 460static int gsm_send_packet(struct gsm_mux *gsm, struct gsm_msg *msg); 461static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr); 462static void gsmld_write_trigger(struct gsm_mux *gsm); 463static void gsmld_write_task(struct work_struct *work); 464static int gsm_modem_send_initial_msc(struct gsm_dlci *dlci); 465 466/** 467 * gsm_fcs_add - update FCS 468 * @fcs: Current FCS 469 * @c: Next data 470 * 471 * Update the FCS to include c. Uses the algorithm in the specification 472 * notes. 473 */ 474 475static inline u8 gsm_fcs_add(u8 fcs, u8 c) 476{ 477 return gsm_fcs8[fcs ^ c]; 478} 479 480/** 481 * gsm_fcs_add_block - update FCS for a block 482 * @fcs: Current FCS 483 * @c: buffer of data 484 * @len: length of buffer 485 * 486 * Update the FCS to include c. Uses the algorithm in the specification 487 * notes. 488 */ 489 490static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len) 491{ 492 while (len--) 493 fcs = gsm_fcs8[fcs ^ *c++]; 494 return fcs; 495} 496 497/** 498 * gsm_read_ea - read a byte into an EA 499 * @val: variable holding value 500 * @c: byte going into the EA 501 * 502 * Processes one byte of an EA. Updates the passed variable 503 * and returns 1 if the EA is now completely read 504 */ 505 506static int gsm_read_ea(unsigned int *val, u8 c) 507{ 508 /* Add the next 7 bits into the value */ 509 *val <<= 7; 510 *val |= c >> 1; 511 /* Was this the last byte of the EA 1 = yes*/ 512 return c & EA; 513} 514 515/** 516 * gsm_read_ea_val - read a value until EA 517 * @val: variable holding value 518 * @data: buffer of data 519 * @dlen: length of data 520 * 521 * Processes an EA value. Updates the passed variable and 522 * returns the processed data length. 523 */ 524static unsigned int gsm_read_ea_val(unsigned int *val, const u8 *data, int dlen) 525{ 526 unsigned int len = 0; 527 528 for (; dlen > 0; dlen--) { 529 len++; 530 if (gsm_read_ea(val, *data++)) 531 break; 532 } 533 return len; 534} 535 536/** 537 * gsm_encode_modem - encode modem data bits 538 * @dlci: DLCI to encode from 539 * 540 * Returns the correct GSM encoded modem status bits (6 bit field) for 541 * the current status of the DLCI and attached tty object 542 */ 543 544static u8 gsm_encode_modem(const struct gsm_dlci *dlci) 545{ 546 u8 modembits = 0; 547 /* FC is true flow control not modem bits */ 548 if (dlci->throttled) 549 modembits |= MDM_FC; 550 if (dlci->modem_tx & TIOCM_DTR) 551 modembits |= MDM_RTC; 552 if (dlci->modem_tx & TIOCM_RTS) 553 modembits |= MDM_RTR; 554 if (dlci->modem_tx & TIOCM_RI) 555 modembits |= MDM_IC; 556 if (dlci->modem_tx & TIOCM_CD || dlci->gsm->initiator) 557 modembits |= MDM_DV; 558 /* special mappings for passive side to operate as UE */ 559 if (dlci->modem_tx & TIOCM_OUT1) 560 modembits |= MDM_IC; 561 if (dlci->modem_tx & TIOCM_OUT2) 562 modembits |= MDM_DV; 563 return modembits; 564} 565 566static void gsm_hex_dump_bytes(const char *fname, const u8 *data, 567 unsigned long len) 568{ 569 char *prefix; 570 571 if (!fname) { 572 print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, 16, 1, data, len, 573 true); 574 return; 575 } 576 577 prefix = kasprintf(GFP_ATOMIC, "%s: ", fname); 578 if (!prefix) 579 return; 580 print_hex_dump(KERN_INFO, prefix, DUMP_PREFIX_OFFSET, 16, 1, data, len, 581 true); 582 kfree(prefix); 583} 584 585/** 586 * gsm_encode_params - encode DLCI parameters 587 * @dlci: DLCI to encode from 588 * @params: buffer to fill with the encoded parameters 589 * 590 * Encodes the parameters according to GSM 07.10 section 5.4.6.3.1 591 * table 3. 592 */ 593static int gsm_encode_params(const struct gsm_dlci *dlci, 594 struct gsm_dlci_param_bits *params) 595{ 596 const struct gsm_mux *gsm = dlci->gsm; 597 unsigned int i, cl; 598 599 switch (dlci->ftype) { 600 case UIH: 601 i = 0; /* UIH */ 602 break; 603 case UI: 604 i = 1; /* UI */ 605 break; 606 default: 607 pr_debug("unsupported frame type %d\n", dlci->ftype); 608 return -EINVAL; 609 } 610 611 switch (dlci->adaption) { 612 case 1: /* Unstructured */ 613 cl = 0; /* convergence layer type 1 */ 614 break; 615 case 2: /* Unstructured with modem bits. */ 616 cl = 1; /* convergence layer type 2 */ 617 break; 618 default: 619 pr_debug("unsupported adaption %d\n", dlci->adaption); 620 return -EINVAL; 621 } 622 623 params->d_bits = FIELD_PREP(PN_D_FIELD_DLCI, dlci->addr); 624 /* UIH, convergence layer type 1 */ 625 params->i_cl_bits = FIELD_PREP(PN_I_CL_FIELD_FTYPE, i) | 626 FIELD_PREP(PN_I_CL_FIELD_ADAPTION, cl); 627 params->p_bits = FIELD_PREP(PN_P_FIELD_PRIO, dlci->prio); 628 params->t_bits = FIELD_PREP(PN_T_FIELD_T1, gsm->t1); 629 params->n_bits = cpu_to_le16(FIELD_PREP(PN_N_FIELD_N1, dlci->mtu)); 630 params->na_bits = FIELD_PREP(PN_NA_FIELD_N2, gsm->n2); 631 params->k_bits = FIELD_PREP(PN_K_FIELD_K, dlci->k); 632 633 return 0; 634} 635 636/** 637 * gsm_register_devices - register all tty devices for a given mux index 638 * 639 * @driver: the tty driver that describes the tty devices 640 * @index: the mux number is used to calculate the minor numbers of the 641 * ttys for this mux and may differ from the position in the 642 * mux array. 643 */ 644static int gsm_register_devices(struct tty_driver *driver, unsigned int index) 645{ 646 struct device *dev; 647 int i; 648 unsigned int base; 649 650 if (!driver || index >= MAX_MUX) 651 return -EINVAL; 652 653 base = index * NUM_DLCI; /* first minor for this index */ 654 for (i = 1; i < NUM_DLCI; i++) { 655 /* Don't register device 0 - this is the control channel 656 * and not a usable tty interface 657 */ 658 dev = tty_register_device(gsm_tty_driver, base + i, NULL); 659 if (IS_ERR(dev)) { 660 if (debug & DBG_ERRORS) 661 pr_info("%s failed to register device minor %u", 662 __func__, base + i); 663 for (i--; i >= 1; i--) 664 tty_unregister_device(gsm_tty_driver, base + i); 665 return PTR_ERR(dev); 666 } 667 } 668 669 return 0; 670} 671 672/** 673 * gsm_unregister_devices - unregister all tty devices for a given mux index 674 * 675 * @driver: the tty driver that describes the tty devices 676 * @index: the mux number is used to calculate the minor numbers of the 677 * ttys for this mux and may differ from the position in the 678 * mux array. 679 */ 680static void gsm_unregister_devices(struct tty_driver *driver, 681 unsigned int index) 682{ 683 int i; 684 unsigned int base; 685 686 if (!driver || index >= MAX_MUX) 687 return; 688 689 base = index * NUM_DLCI; /* first minor for this index */ 690 for (i = 1; i < NUM_DLCI; i++) { 691 /* Don't unregister device 0 - this is the control 692 * channel and not a usable tty interface 693 */ 694 tty_unregister_device(gsm_tty_driver, base + i); 695 } 696} 697 698/** 699 * gsm_print_packet - display a frame for debug 700 * @hdr: header to print before decode 701 * @addr: address EA from the frame 702 * @cr: C/R bit seen as initiator 703 * @control: control including PF bit 704 * @data: following data bytes 705 * @dlen: length of data 706 * 707 * Displays a packet in human readable format for debugging purposes. The 708 * style is based on amateur radio LAP-B dump display. 709 */ 710 711static void gsm_print_packet(const char *hdr, int addr, int cr, 712 u8 control, const u8 *data, int dlen) 713{ 714 if (!(debug & DBG_DUMP)) 715 return; 716 /* Only show user payload frames if debug & DBG_PAYLOAD */ 717 if (!(debug & DBG_PAYLOAD) && addr != 0) 718 if ((control & ~PF) == UI || (control & ~PF) == UIH) 719 return; 720 721 pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]); 722 723 switch (control & ~PF) { 724 case SABM: 725 pr_cont("SABM"); 726 break; 727 case UA: 728 pr_cont("UA"); 729 break; 730 case DISC: 731 pr_cont("DISC"); 732 break; 733 case DM: 734 pr_cont("DM"); 735 break; 736 case UI: 737 pr_cont("UI"); 738 break; 739 case UIH: 740 pr_cont("UIH"); 741 break; 742 default: 743 if (!(control & 0x01)) { 744 pr_cont("I N(S)%d N(R)%d", 745 (control & 0x0E) >> 1, (control & 0xE0) >> 5); 746 } else switch (control & 0x0F) { 747 case RR: 748 pr_cont("RR(%d)", (control & 0xE0) >> 5); 749 break; 750 case RNR: 751 pr_cont("RNR(%d)", (control & 0xE0) >> 5); 752 break; 753 case REJ: 754 pr_cont("REJ(%d)", (control & 0xE0) >> 5); 755 break; 756 default: 757 pr_cont("[%02X]", control); 758 } 759 } 760 761 if (control & PF) 762 pr_cont("(P)"); 763 else 764 pr_cont("(F)"); 765 766 gsm_hex_dump_bytes(NULL, data, dlen); 767} 768 769 770/* 771 * Link level transmission side 772 */ 773 774/** 775 * gsm_stuff_frame - bytestuff a packet 776 * @input: input buffer 777 * @output: output buffer 778 * @len: length of input 779 * 780 * Expand a buffer by bytestuffing it. The worst case size change 781 * is doubling and the caller is responsible for handing out 782 * suitable sized buffers. 783 */ 784 785static int gsm_stuff_frame(const u8 *input, u8 *output, int len) 786{ 787 int olen = 0; 788 while (len--) { 789 if (*input == GSM1_SOF || *input == GSM1_ESCAPE 790 || (*input & ISO_IEC_646_MASK) == XON 791 || (*input & ISO_IEC_646_MASK) == XOFF) { 792 *output++ = GSM1_ESCAPE; 793 *output++ = *input++ ^ GSM1_ESCAPE_BITS; 794 olen++; 795 } else 796 *output++ = *input++; 797 olen++; 798 } 799 return olen; 800} 801 802/** 803 * gsm_send - send a control frame 804 * @gsm: our GSM mux 805 * @addr: address for control frame 806 * @cr: command/response bit seen as initiator 807 * @control: control byte including PF bit 808 * 809 * Format up and transmit a control frame. These should be transmitted 810 * ahead of data when they are needed. 811 */ 812static int gsm_send(struct gsm_mux *gsm, int addr, int cr, int control) 813{ 814 struct gsm_msg *msg; 815 u8 *dp; 816 int ocr; 817 unsigned long flags; 818 819 msg = gsm_data_alloc(gsm, addr, 0, control); 820 if (!msg) 821 return -ENOMEM; 822 823 /* toggle C/R coding if not initiator */ 824 ocr = cr ^ (gsm->initiator ? 0 : 1); 825 826 msg->data -= 3; 827 dp = msg->data; 828 *dp++ = (addr << 2) | (ocr << 1) | EA; 829 *dp++ = control; 830 831 if (gsm->encoding == GSM_BASIC_OPT) 832 *dp++ = EA; /* Length of data = 0 */ 833 834 *dp = 0xFF - gsm_fcs_add_block(INIT_FCS, msg->data, dp - msg->data); 835 msg->len = (dp - msg->data) + 1; 836 837 gsm_print_packet("Q->", addr, cr, control, NULL, 0); 838 839 spin_lock_irqsave(&gsm->tx_lock, flags); 840 list_add_tail(&msg->list, &gsm->tx_ctrl_list); 841 gsm->tx_bytes += msg->len; 842 spin_unlock_irqrestore(&gsm->tx_lock, flags); 843 gsmld_write_trigger(gsm); 844 845 return 0; 846} 847 848/** 849 * gsm_dlci_clear_queues - remove outstanding data for a DLCI 850 * @gsm: mux 851 * @dlci: clear for this DLCI 852 * 853 * Clears the data queues for a given DLCI. 854 */ 855static void gsm_dlci_clear_queues(struct gsm_mux *gsm, struct gsm_dlci *dlci) 856{ 857 struct gsm_msg *msg, *nmsg; 858 int addr = dlci->addr; 859 unsigned long flags; 860 861 /* Clear DLCI write fifo first */ 862 spin_lock_irqsave(&dlci->lock, flags); 863 kfifo_reset(&dlci->fifo); 864 spin_unlock_irqrestore(&dlci->lock, flags); 865 866 /* Clear data packets in MUX write queue */ 867 spin_lock_irqsave(&gsm->tx_lock, flags); 868 list_for_each_entry_safe(msg, nmsg, &gsm->tx_data_list, list) { 869 if (msg->addr != addr) 870 continue; 871 gsm->tx_bytes -= msg->len; 872 list_del(&msg->list); 873 kfree(msg); 874 } 875 spin_unlock_irqrestore(&gsm->tx_lock, flags); 876} 877 878/** 879 * gsm_response - send a control response 880 * @gsm: our GSM mux 881 * @addr: address for control frame 882 * @control: control byte including PF bit 883 * 884 * Format up and transmit a link level response frame. 885 */ 886 887static inline void gsm_response(struct gsm_mux *gsm, int addr, int control) 888{ 889 gsm_send(gsm, addr, 0, control); 890} 891 892/** 893 * gsm_command - send a control command 894 * @gsm: our GSM mux 895 * @addr: address for control frame 896 * @control: control byte including PF bit 897 * 898 * Format up and transmit a link level command frame. 899 */ 900 901static inline void gsm_command(struct gsm_mux *gsm, int addr, int control) 902{ 903 gsm_send(gsm, addr, 1, control); 904} 905 906/* Data transmission */ 907 908#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */ 909 910/** 911 * gsm_data_alloc - allocate data frame 912 * @gsm: GSM mux 913 * @addr: DLCI address 914 * @len: length excluding header and FCS 915 * @ctrl: control byte 916 * 917 * Allocate a new data buffer for sending frames with data. Space is left 918 * at the front for header bytes but that is treated as an implementation 919 * detail and not for the high level code to use 920 */ 921 922static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len, 923 u8 ctrl) 924{ 925 struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN, 926 GFP_ATOMIC); 927 if (m == NULL) 928 return NULL; 929 m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */ 930 m->len = len; 931 m->addr = addr; 932 m->ctrl = ctrl; 933 INIT_LIST_HEAD(&m->list); 934 return m; 935} 936 937/** 938 * gsm_send_packet - sends a single packet 939 * @gsm: GSM Mux 940 * @msg: packet to send 941 * 942 * The given packet is encoded and sent out. No memory is freed. 943 * The caller must hold the gsm tx lock. 944 */ 945static int gsm_send_packet(struct gsm_mux *gsm, struct gsm_msg *msg) 946{ 947 int len, ret; 948 949 950 if (gsm->encoding == GSM_BASIC_OPT) { 951 gsm->txframe[0] = GSM0_SOF; 952 memcpy(gsm->txframe + 1, msg->data, msg->len); 953 gsm->txframe[msg->len + 1] = GSM0_SOF; 954 len = msg->len + 2; 955 } else { 956 gsm->txframe[0] = GSM1_SOF; 957 len = gsm_stuff_frame(msg->data, gsm->txframe + 1, msg->len); 958 gsm->txframe[len + 1] = GSM1_SOF; 959 len += 2; 960 } 961 962 if (debug & DBG_DATA) 963 gsm_hex_dump_bytes(__func__, gsm->txframe, len); 964 gsm_print_packet("-->", msg->addr, gsm->initiator, msg->ctrl, msg->data, 965 msg->len); 966 967 ret = gsmld_output(gsm, gsm->txframe, len); 968 if (ret <= 0) 969 return ret; 970 /* FIXME: Can eliminate one SOF in many more cases */ 971 gsm->tx_bytes -= msg->len; 972 973 return 0; 974} 975 976/** 977 * gsm_is_flow_ctrl_msg - checks if flow control message 978 * @msg: message to check 979 * 980 * Returns true if the given message is a flow control command of the 981 * control channel. False is returned in any other case. 982 */ 983static bool gsm_is_flow_ctrl_msg(struct gsm_msg *msg) 984{ 985 unsigned int cmd; 986 987 if (msg->addr > 0) 988 return false; 989 990 switch (msg->ctrl & ~PF) { 991 case UI: 992 case UIH: 993 cmd = 0; 994 if (gsm_read_ea_val(&cmd, msg->data + 2, msg->len - 2) < 1) 995 break; 996 switch (cmd & ~PF) { 997 case CMD_FCOFF: 998 case CMD_FCON: 999 return true; 1000 } 1001 break; 1002 } 1003 1004 return false; 1005} 1006 1007/** 1008 * gsm_data_kick - poke the queue 1009 * @gsm: GSM Mux 1010 * 1011 * The tty device has called us to indicate that room has appeared in 1012 * the transmit queue. Ram more data into the pipe if we have any. 1013 * If we have been flow-stopped by a CMD_FCOFF, then we can only 1014 * send messages on DLCI0 until CMD_FCON. The caller must hold 1015 * the gsm tx lock. 1016 */ 1017static int gsm_data_kick(struct gsm_mux *gsm) 1018{ 1019 struct gsm_msg *msg, *nmsg; 1020 struct gsm_dlci *dlci; 1021 int ret; 1022 1023 clear_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags); 1024 1025 /* Serialize control messages and control channel messages first */ 1026 list_for_each_entry_safe(msg, nmsg, &gsm->tx_ctrl_list, list) { 1027 if (gsm->constipated && !gsm_is_flow_ctrl_msg(msg)) 1028 continue; 1029 ret = gsm_send_packet(gsm, msg); 1030 switch (ret) { 1031 case -ENOSPC: 1032 return -ENOSPC; 1033 case -ENODEV: 1034 /* ldisc not open */ 1035 gsm->tx_bytes -= msg->len; 1036 list_del(&msg->list); 1037 kfree(msg); 1038 continue; 1039 default: 1040 if (ret >= 0) { 1041 list_del(&msg->list); 1042 kfree(msg); 1043 } 1044 break; 1045 } 1046 } 1047 1048 if (gsm->constipated) 1049 return -EAGAIN; 1050 1051 /* Serialize other channels */ 1052 if (list_empty(&gsm->tx_data_list)) 1053 return 0; 1054 list_for_each_entry_safe(msg, nmsg, &gsm->tx_data_list, list) { 1055 dlci = gsm->dlci[msg->addr]; 1056 /* Send only messages for DLCIs with valid state */ 1057 if (dlci->state != DLCI_OPEN) { 1058 gsm->tx_bytes -= msg->len; 1059 list_del(&msg->list); 1060 kfree(msg); 1061 continue; 1062 } 1063 ret = gsm_send_packet(gsm, msg); 1064 switch (ret) { 1065 case -ENOSPC: 1066 return -ENOSPC; 1067 case -ENODEV: 1068 /* ldisc not open */ 1069 gsm->tx_bytes -= msg->len; 1070 list_del(&msg->list); 1071 kfree(msg); 1072 continue; 1073 default: 1074 if (ret >= 0) { 1075 list_del(&msg->list); 1076 kfree(msg); 1077 } 1078 break; 1079 } 1080 } 1081 1082 return 1; 1083} 1084 1085/** 1086 * __gsm_data_queue - queue a UI or UIH frame 1087 * @dlci: DLCI sending the data 1088 * @msg: message queued 1089 * 1090 * Add data to the transmit queue and try and get stuff moving 1091 * out of the mux tty if not already doing so. The Caller must hold 1092 * the gsm tx lock. 1093 */ 1094 1095static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) 1096{ 1097 struct gsm_mux *gsm = dlci->gsm; 1098 u8 *dp = msg->data; 1099 u8 *fcs = dp + msg->len; 1100 1101 /* Fill in the header */ 1102 if (gsm->encoding == GSM_BASIC_OPT) { 1103 if (msg->len < 128) 1104 *--dp = (msg->len << 1) | EA; 1105 else { 1106 *--dp = (msg->len >> 7); /* bits 7 - 15 */ 1107 *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */ 1108 } 1109 } 1110 1111 *--dp = msg->ctrl; 1112 if (gsm->initiator) 1113 *--dp = (msg->addr << 2) | CR | EA; 1114 else 1115 *--dp = (msg->addr << 2) | EA; 1116 *fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp); 1117 /* Ugly protocol layering violation */ 1118 if (msg->ctrl == UI || msg->ctrl == (UI|PF)) 1119 *fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len); 1120 *fcs = 0xFF - *fcs; 1121 1122 gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl, 1123 msg->data, msg->len); 1124 1125 /* Move the header back and adjust the length, also allow for the FCS 1126 now tacked on the end */ 1127 msg->len += (msg->data - dp) + 1; 1128 msg->data = dp; 1129 1130 /* Add to the actual output queue */ 1131 switch (msg->ctrl & ~PF) { 1132 case UI: 1133 case UIH: 1134 if (msg->addr > 0) { 1135 list_add_tail(&msg->list, &gsm->tx_data_list); 1136 break; 1137 } 1138 fallthrough; 1139 default: 1140 list_add_tail(&msg->list, &gsm->tx_ctrl_list); 1141 break; 1142 } 1143 gsm->tx_bytes += msg->len; 1144 1145 gsmld_write_trigger(gsm); 1146 mod_timer(&gsm->kick_timer, jiffies + 10 * gsm->t1 * HZ / 100); 1147} 1148 1149/** 1150 * gsm_data_queue - queue a UI or UIH frame 1151 * @dlci: DLCI sending the data 1152 * @msg: message queued 1153 * 1154 * Add data to the transmit queue and try and get stuff moving 1155 * out of the mux tty if not already doing so. Take the 1156 * the gsm tx lock and dlci lock. 1157 */ 1158 1159static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) 1160{ 1161 unsigned long flags; 1162 spin_lock_irqsave(&dlci->gsm->tx_lock, flags); 1163 __gsm_data_queue(dlci, msg); 1164 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); 1165} 1166 1167/** 1168 * gsm_dlci_data_output - try and push data out of a DLCI 1169 * @gsm: mux 1170 * @dlci: the DLCI to pull data from 1171 * 1172 * Pull data from a DLCI and send it into the transmit queue if there 1173 * is data. Keep to the MRU of the mux. This path handles the usual tty 1174 * interface which is a byte stream with optional modem data. 1175 * 1176 * Caller must hold the tx_lock of the mux. 1177 */ 1178 1179static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci) 1180{ 1181 struct gsm_msg *msg; 1182 u8 *dp; 1183 int h, len, size; 1184 1185 /* for modem bits without break data */ 1186 h = ((dlci->adaption == 1) ? 0 : 1); 1187 1188 len = kfifo_len(&dlci->fifo); 1189 if (len == 0) 1190 return 0; 1191 1192 /* MTU/MRU count only the data bits but watch adaption mode */ 1193 if ((len + h) > dlci->mtu) 1194 len = dlci->mtu - h; 1195 1196 size = len + h; 1197 1198 msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype); 1199 if (!msg) 1200 return -ENOMEM; 1201 dp = msg->data; 1202 switch (dlci->adaption) { 1203 case 1: /* Unstructured */ 1204 break; 1205 case 2: /* Unstructured with modem bits. 1206 * Always one byte as we never send inline break data 1207 */ 1208 *dp++ = (gsm_encode_modem(dlci) << 1) | EA; 1209 break; 1210 default: 1211 pr_err("%s: unsupported adaption %d\n", __func__, 1212 dlci->adaption); 1213 break; 1214 } 1215 1216 WARN_ON(len != kfifo_out_locked(&dlci->fifo, dp, len, 1217 &dlci->lock)); 1218 1219 /* Notify upper layer about available send space. */ 1220 tty_port_tty_wakeup(&dlci->port); 1221 1222 __gsm_data_queue(dlci, msg); 1223 /* Bytes of data we used up */ 1224 return size; 1225} 1226 1227/** 1228 * gsm_dlci_data_output_framed - try and push data out of a DLCI 1229 * @gsm: mux 1230 * @dlci: the DLCI to pull data from 1231 * 1232 * Pull data from a DLCI and send it into the transmit queue if there 1233 * is data. Keep to the MRU of the mux. This path handles framed data 1234 * queued as skbuffs to the DLCI. 1235 * 1236 * Caller must hold the tx_lock of the mux. 1237 */ 1238 1239static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, 1240 struct gsm_dlci *dlci) 1241{ 1242 struct gsm_msg *msg; 1243 u8 *dp; 1244 int len, size; 1245 int last = 0, first = 0; 1246 int overhead = 0; 1247 1248 /* One byte per frame is used for B/F flags */ 1249 if (dlci->adaption == 4) 1250 overhead = 1; 1251 1252 /* dlci->skb is locked by tx_lock */ 1253 if (dlci->skb == NULL) { 1254 dlci->skb = skb_dequeue_tail(&dlci->skb_list); 1255 if (dlci->skb == NULL) 1256 return 0; 1257 first = 1; 1258 } 1259 len = dlci->skb->len + overhead; 1260 1261 /* MTU/MRU count only the data bits */ 1262 if (len > dlci->mtu) { 1263 if (dlci->adaption == 3) { 1264 /* Over long frame, bin it */ 1265 dev_kfree_skb_any(dlci->skb); 1266 dlci->skb = NULL; 1267 return 0; 1268 } 1269 len = dlci->mtu; 1270 } else 1271 last = 1; 1272 1273 size = len + overhead; 1274 msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype); 1275 if (msg == NULL) { 1276 skb_queue_tail(&dlci->skb_list, dlci->skb); 1277 dlci->skb = NULL; 1278 return -ENOMEM; 1279 } 1280 dp = msg->data; 1281 1282 if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */ 1283 /* Flag byte to carry the start/end info */ 1284 *dp++ = last << 7 | first << 6 | 1; /* EA */ 1285 len--; 1286 } 1287 memcpy(dp, dlci->skb->data, len); 1288 skb_pull(dlci->skb, len); 1289 __gsm_data_queue(dlci, msg); 1290 if (last) { 1291 dev_kfree_skb_any(dlci->skb); 1292 dlci->skb = NULL; 1293 } 1294 return size; 1295} 1296 1297/** 1298 * gsm_dlci_modem_output - try and push modem status out of a DLCI 1299 * @gsm: mux 1300 * @dlci: the DLCI to pull modem status from 1301 * @brk: break signal 1302 * 1303 * Push an empty frame in to the transmit queue to update the modem status 1304 * bits and to transmit an optional break. 1305 * 1306 * Caller must hold the tx_lock of the mux. 1307 */ 1308 1309static int gsm_dlci_modem_output(struct gsm_mux *gsm, struct gsm_dlci *dlci, 1310 u8 brk) 1311{ 1312 u8 *dp = NULL; 1313 struct gsm_msg *msg; 1314 int size = 0; 1315 1316 /* for modem bits without break data */ 1317 switch (dlci->adaption) { 1318 case 1: /* Unstructured */ 1319 break; 1320 case 2: /* Unstructured with modem bits. */ 1321 size++; 1322 if (brk > 0) 1323 size++; 1324 break; 1325 default: 1326 pr_err("%s: unsupported adaption %d\n", __func__, 1327 dlci->adaption); 1328 return -EINVAL; 1329 } 1330 1331 msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype); 1332 if (!msg) { 1333 pr_err("%s: gsm_data_alloc error", __func__); 1334 return -ENOMEM; 1335 } 1336 dp = msg->data; 1337 switch (dlci->adaption) { 1338 case 1: /* Unstructured */ 1339 break; 1340 case 2: /* Unstructured with modem bits. */ 1341 if (brk == 0) { 1342 *dp++ = (gsm_encode_modem(dlci) << 1) | EA; 1343 } else { 1344 *dp++ = gsm_encode_modem(dlci) << 1; 1345 *dp++ = (brk << 4) | 2 | EA; /* Length, Break, EA */ 1346 } 1347 break; 1348 default: 1349 /* Handled above */ 1350 break; 1351 } 1352 1353 __gsm_data_queue(dlci, msg); 1354 return size; 1355} 1356 1357/** 1358 * gsm_dlci_data_sweep - look for data to send 1359 * @gsm: the GSM mux 1360 * 1361 * Sweep the GSM mux channels in priority order looking for ones with 1362 * data to send. We could do with optimising this scan a bit. We aim 1363 * to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit 1364 * TX_THRESH_LO we get called again 1365 * 1366 * FIXME: We should round robin between groups and in theory you can 1367 * renegotiate DLCI priorities with optional stuff. Needs optimising. 1368 */ 1369 1370static int gsm_dlci_data_sweep(struct gsm_mux *gsm) 1371{ 1372 /* Priority ordering: We should do priority with RR of the groups */ 1373 int i, len, ret = 0; 1374 bool sent; 1375 struct gsm_dlci *dlci; 1376 1377 while (gsm->tx_bytes < TX_THRESH_HI) { 1378 for (sent = false, i = 1; i < NUM_DLCI; i++) { 1379 dlci = gsm->dlci[i]; 1380 /* skip unused or blocked channel */ 1381 if (!dlci || dlci->constipated) 1382 continue; 1383 /* skip channels with invalid state */ 1384 if (dlci->state != DLCI_OPEN) 1385 continue; 1386 /* count the sent data per adaption */ 1387 if (dlci->adaption < 3 && !dlci->net) 1388 len = gsm_dlci_data_output(gsm, dlci); 1389 else 1390 len = gsm_dlci_data_output_framed(gsm, dlci); 1391 /* on error exit */ 1392 if (len < 0) 1393 return ret; 1394 if (len > 0) { 1395 ret++; 1396 sent = true; 1397 /* The lower DLCs can starve the higher DLCs! */ 1398 break; 1399 } 1400 /* try next */ 1401 } 1402 if (!sent) 1403 break; 1404 } 1405 1406 return ret; 1407} 1408 1409/** 1410 * gsm_dlci_data_kick - transmit if possible 1411 * @dlci: DLCI to kick 1412 * 1413 * Transmit data from this DLCI if the queue is empty. We can't rely on 1414 * a tty wakeup except when we filled the pipe so we need to fire off 1415 * new data ourselves in other cases. 1416 */ 1417 1418static void gsm_dlci_data_kick(struct gsm_dlci *dlci) 1419{ 1420 unsigned long flags; 1421 int sweep; 1422 1423 if (dlci->constipated) 1424 return; 1425 1426 spin_lock_irqsave(&dlci->gsm->tx_lock, flags); 1427 /* If we have nothing running then we need to fire up */ 1428 sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO); 1429 if (dlci->gsm->tx_bytes == 0) { 1430 if (dlci->net) 1431 gsm_dlci_data_output_framed(dlci->gsm, dlci); 1432 else 1433 gsm_dlci_data_output(dlci->gsm, dlci); 1434 } 1435 if (sweep) 1436 gsm_dlci_data_sweep(dlci->gsm); 1437 spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags); 1438} 1439 1440/* 1441 * Control message processing 1442 */ 1443 1444 1445/** 1446 * gsm_control_command - send a command frame to a control 1447 * @gsm: gsm channel 1448 * @cmd: the command to use 1449 * @data: data to follow encoded info 1450 * @dlen: length of data 1451 * 1452 * Encode up and queue a UI/UIH frame containing our command. 1453 */ 1454static int gsm_control_command(struct gsm_mux *gsm, int cmd, const u8 *data, 1455 int dlen) 1456{ 1457 struct gsm_msg *msg; 1458 struct gsm_dlci *dlci = gsm->dlci[0]; 1459 1460 msg = gsm_data_alloc(gsm, 0, dlen + 2, dlci->ftype); 1461 if (msg == NULL) 1462 return -ENOMEM; 1463 1464 msg->data[0] = (cmd << 1) | CR | EA; /* Set C/R */ 1465 msg->data[1] = (dlen << 1) | EA; 1466 memcpy(msg->data + 2, data, dlen); 1467 gsm_data_queue(dlci, msg); 1468 1469 return 0; 1470} 1471 1472/** 1473 * gsm_control_reply - send a response frame to a control 1474 * @gsm: gsm channel 1475 * @cmd: the command to use 1476 * @data: data to follow encoded info 1477 * @dlen: length of data 1478 * 1479 * Encode up and queue a UI/UIH frame containing our response. 1480 */ 1481 1482static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data, 1483 int dlen) 1484{ 1485 struct gsm_msg *msg; 1486 struct gsm_dlci *dlci = gsm->dlci[0]; 1487 1488 msg = gsm_data_alloc(gsm, 0, dlen + 2, dlci->ftype); 1489 if (msg == NULL) 1490 return; 1491 msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */ 1492 msg->data[1] = (dlen << 1) | EA; 1493 memcpy(msg->data + 2, data, dlen); 1494 gsm_data_queue(dlci, msg); 1495} 1496 1497/** 1498 * gsm_process_modem - process received modem status 1499 * @tty: virtual tty bound to the DLCI 1500 * @dlci: DLCI to affect 1501 * @modem: modem bits (full EA) 1502 * @slen: number of signal octets 1503 * 1504 * Used when a modem control message or line state inline in adaption 1505 * layer 2 is processed. Sort out the local modem state and throttles 1506 */ 1507 1508static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci, 1509 u32 modem, int slen) 1510{ 1511 int mlines = 0; 1512 u8 brk = 0; 1513 int fc; 1514 1515 /* The modem status command can either contain one octet (V.24 signals) 1516 * or two octets (V.24 signals + break signals). This is specified in 1517 * section 5.4.6.3.7 of the 07.10 mux spec. 1518 */ 1519 1520 if (slen == 1) 1521 modem = modem & 0x7f; 1522 else { 1523 brk = modem & 0x7f; 1524 modem = (modem >> 7) & 0x7f; 1525 } 1526 1527 /* Flow control/ready to communicate */ 1528 fc = (modem & MDM_FC) || !(modem & MDM_RTR); 1529 if (fc && !dlci->constipated) { 1530 /* Need to throttle our output on this device */ 1531 dlci->constipated = true; 1532 } else if (!fc && dlci->constipated) { 1533 dlci->constipated = false; 1534 gsm_dlci_data_kick(dlci); 1535 } 1536 1537 /* Map modem bits */ 1538 if (modem & MDM_RTC) 1539 mlines |= TIOCM_DSR | TIOCM_DTR; 1540 if (modem & MDM_RTR) 1541 mlines |= TIOCM_RTS | TIOCM_CTS; 1542 if (modem & MDM_IC) 1543 mlines |= TIOCM_RI; 1544 if (modem & MDM_DV) 1545 mlines |= TIOCM_CD; 1546 1547 /* Carrier drop -> hangup */ 1548 if (tty) { 1549 if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD)) 1550 if (!C_CLOCAL(tty)) 1551 tty_hangup(tty); 1552 } 1553 if (brk & 0x01) 1554 tty_insert_flip_char(&dlci->port, 0, TTY_BREAK); 1555 dlci->modem_rx = mlines; 1556 wake_up_interruptible(&dlci->gsm->event); 1557} 1558 1559/** 1560 * gsm_process_negotiation - process received parameters 1561 * @gsm: GSM channel 1562 * @addr: DLCI address 1563 * @cr: command/response 1564 * @params: encoded parameters from the parameter negotiation message 1565 * 1566 * Used when the response for our parameter negotiation command was 1567 * received. 1568 */ 1569static int gsm_process_negotiation(struct gsm_mux *gsm, unsigned int addr, 1570 unsigned int cr, 1571 const struct gsm_dlci_param_bits *params) 1572{ 1573 struct gsm_dlci *dlci = gsm->dlci[addr]; 1574 unsigned int ftype, i, adaption, prio, n1, k; 1575 1576 i = FIELD_GET(PN_I_CL_FIELD_FTYPE, params->i_cl_bits); 1577 adaption = FIELD_GET(PN_I_CL_FIELD_ADAPTION, params->i_cl_bits) + 1; 1578 prio = FIELD_GET(PN_P_FIELD_PRIO, params->p_bits); 1579 n1 = FIELD_GET(PN_N_FIELD_N1, get_unaligned_le16(¶ms->n_bits)); 1580 k = FIELD_GET(PN_K_FIELD_K, params->k_bits); 1581 1582 if (n1 < MIN_MTU) { 1583 if (debug & DBG_ERRORS) 1584 pr_info("%s N1 out of range in PN\n", __func__); 1585 return -EINVAL; 1586 } 1587 1588 switch (i) { 1589 case 0x00: 1590 ftype = UIH; 1591 break; 1592 case 0x01: 1593 ftype = UI; 1594 break; 1595 case 0x02: /* I frames are not supported */ 1596 if (debug & DBG_ERRORS) 1597 pr_info("%s unsupported I frame request in PN\n", 1598 __func__); 1599 gsm->unsupported++; 1600 return -EINVAL; 1601 default: 1602 if (debug & DBG_ERRORS) 1603 pr_info("%s i out of range in PN\n", __func__); 1604 return -EINVAL; 1605 } 1606 1607 if (!cr && gsm->initiator) { 1608 if (adaption != dlci->adaption) { 1609 if (debug & DBG_ERRORS) 1610 pr_info("%s invalid adaption %d in PN\n", 1611 __func__, adaption); 1612 return -EINVAL; 1613 } 1614 if (prio != dlci->prio) { 1615 if (debug & DBG_ERRORS) 1616 pr_info("%s invalid priority %d in PN", 1617 __func__, prio); 1618 return -EINVAL; 1619 } 1620 if (n1 > gsm->mru || n1 > dlci->mtu) { 1621 /* We requested a frame size but the other party wants 1622 * to send larger frames. The standard allows only a 1623 * smaller response value than requested (5.4.6.3.1). 1624 */ 1625 if (debug & DBG_ERRORS) 1626 pr_info("%s invalid N1 %d in PN\n", __func__, 1627 n1); 1628 return -EINVAL; 1629 } 1630 dlci->mtu = n1; 1631 if (ftype != dlci->ftype) { 1632 if (debug & DBG_ERRORS) 1633 pr_info("%s invalid i %d in PN\n", __func__, i); 1634 return -EINVAL; 1635 } 1636 if (ftype != UI && ftype != UIH && k > dlci->k) { 1637 if (debug & DBG_ERRORS) 1638 pr_info("%s invalid k %d in PN\n", __func__, k); 1639 return -EINVAL; 1640 } 1641 dlci->k = k; 1642 } else if (cr && !gsm->initiator) { 1643 /* Only convergence layer type 1 and 2 are supported. */ 1644 if (adaption != 1 && adaption != 2) { 1645 if (debug & DBG_ERRORS) 1646 pr_info("%s invalid adaption %d in PN\n", 1647 __func__, adaption); 1648 return -EINVAL; 1649 } 1650 dlci->adaption = adaption; 1651 if (n1 > gsm->mru) { 1652 /* Propose a smaller value */ 1653 dlci->mtu = gsm->mru; 1654 } else if (n1 > MAX_MTU) { 1655 /* Propose a smaller value */ 1656 dlci->mtu = MAX_MTU; 1657 } else { 1658 dlci->mtu = n1; 1659 } 1660 dlci->prio = prio; 1661 dlci->ftype = ftype; 1662 dlci->k = k; 1663 } else { 1664 return -EINVAL; 1665 } 1666 1667 return 0; 1668} 1669 1670/** 1671 * gsm_control_modem - modem status received 1672 * @gsm: GSM channel 1673 * @data: data following command 1674 * @clen: command length 1675 * 1676 * We have received a modem status control message. This is used by 1677 * the GSM mux protocol to pass virtual modem line status and optionally 1678 * to indicate break signals. Unpack it, convert to Linux representation 1679 * and if need be stuff a break message down the tty. 1680 */ 1681 1682static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen) 1683{ 1684 unsigned int addr = 0; 1685 unsigned int modem = 0; 1686 struct gsm_dlci *dlci; 1687 int len = clen; 1688 int cl = clen; 1689 const u8 *dp = data; 1690 struct tty_struct *tty; 1691 1692 len = gsm_read_ea_val(&addr, data, cl); 1693 if (len < 1) 1694 return; 1695 1696 addr >>= 1; 1697 /* Closed port, or invalid ? */ 1698 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) 1699 return; 1700 dlci = gsm->dlci[addr]; 1701 1702 /* Must be at least one byte following the EA */ 1703 if ((cl - len) < 1) 1704 return; 1705 1706 dp += len; 1707 cl -= len; 1708 1709 /* get the modem status */ 1710 len = gsm_read_ea_val(&modem, dp, cl); 1711 if (len < 1) 1712 return; 1713 1714 tty = tty_port_tty_get(&dlci->port); 1715 gsm_process_modem(tty, dlci, modem, cl); 1716 if (tty) { 1717 tty_wakeup(tty); 1718 tty_kref_put(tty); 1719 } 1720 gsm_control_reply(gsm, CMD_MSC, data, clen); 1721} 1722 1723/** 1724 * gsm_control_negotiation - parameter negotiation received 1725 * @gsm: GSM channel 1726 * @cr: command/response flag 1727 * @data: data following command 1728 * @dlen: data length 1729 * 1730 * We have received a parameter negotiation message. This is used by 1731 * the GSM mux protocol to configure protocol parameters for a new DLCI. 1732 */ 1733static void gsm_control_negotiation(struct gsm_mux *gsm, unsigned int cr, 1734 const u8 *data, unsigned int dlen) 1735{ 1736 unsigned int addr; 1737 struct gsm_dlci_param_bits pn_reply; 1738 struct gsm_dlci *dlci; 1739 struct gsm_dlci_param_bits *params; 1740 1741 if (dlen < sizeof(struct gsm_dlci_param_bits)) { 1742 gsm->open_error++; 1743 return; 1744 } 1745 1746 /* Invalid DLCI? */ 1747 params = (struct gsm_dlci_param_bits *)data; 1748 addr = FIELD_GET(PN_D_FIELD_DLCI, params->d_bits); 1749 if (addr == 0 || addr >= NUM_DLCI || !gsm->dlci[addr]) { 1750 gsm->open_error++; 1751 return; 1752 } 1753 dlci = gsm->dlci[addr]; 1754 1755 /* Too late for parameter negotiation? */ 1756 if ((!cr && dlci->state == DLCI_OPENING) || dlci->state == DLCI_OPEN) { 1757 gsm->open_error++; 1758 return; 1759 } 1760 1761 /* Process the received parameters */ 1762 if (gsm_process_negotiation(gsm, addr, cr, params) != 0) { 1763 /* Negotiation failed. Close the link. */ 1764 if (debug & DBG_ERRORS) 1765 pr_info("%s PN failed\n", __func__); 1766 gsm->open_error++; 1767 gsm_dlci_close(dlci); 1768 return; 1769 } 1770 1771 if (cr) { 1772 /* Reply command with accepted parameters. */ 1773 if (gsm_encode_params(dlci, &pn_reply) == 0) 1774 gsm_control_reply(gsm, CMD_PN, (const u8 *)&pn_reply, 1775 sizeof(pn_reply)); 1776 else if (debug & DBG_ERRORS) 1777 pr_info("%s PN invalid\n", __func__); 1778 } else if (dlci->state == DLCI_CONFIGURE) { 1779 /* Proceed with link setup by sending SABM before UA */ 1780 dlci->state = DLCI_OPENING; 1781 gsm_command(gsm, dlci->addr, SABM|PF); 1782 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 1783 } else { 1784 if (debug & DBG_ERRORS) 1785 pr_info("%s PN in invalid state\n", __func__); 1786 gsm->open_error++; 1787 } 1788} 1789 1790/** 1791 * gsm_control_rls - remote line status 1792 * @gsm: GSM channel 1793 * @data: data bytes 1794 * @clen: data length 1795 * 1796 * The modem sends us a two byte message on the control channel whenever 1797 * it wishes to send us an error state from the virtual link. Stuff 1798 * this into the uplink tty if present 1799 */ 1800 1801static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen) 1802{ 1803 struct tty_port *port; 1804 unsigned int addr = 0; 1805 u8 bits; 1806 int len = clen; 1807 const u8 *dp = data; 1808 1809 while (gsm_read_ea(&addr, *dp++) == 0) { 1810 len--; 1811 if (len == 0) 1812 return; 1813 } 1814 /* Must be at least one byte following ea */ 1815 len--; 1816 if (len <= 0) 1817 return; 1818 addr >>= 1; 1819 /* Closed port, or invalid ? */ 1820 if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL) 1821 return; 1822 /* No error ? */ 1823 bits = *dp; 1824 if ((bits & 1) == 0) 1825 return; 1826 1827 port = &gsm->dlci[addr]->port; 1828 1829 if (bits & 2) 1830 tty_insert_flip_char(port, 0, TTY_OVERRUN); 1831 if (bits & 4) 1832 tty_insert_flip_char(port, 0, TTY_PARITY); 1833 if (bits & 8) 1834 tty_insert_flip_char(port, 0, TTY_FRAME); 1835 1836 tty_flip_buffer_push(port); 1837 1838 gsm_control_reply(gsm, CMD_RLS, data, clen); 1839} 1840 1841static void gsm_dlci_begin_close(struct gsm_dlci *dlci); 1842 1843/** 1844 * gsm_control_message - DLCI 0 control processing 1845 * @gsm: our GSM mux 1846 * @command: the command EA 1847 * @data: data beyond the command/length EAs 1848 * @clen: length 1849 * 1850 * Input processor for control messages from the other end of the link. 1851 * Processes the incoming request and queues a response frame or an 1852 * NSC response if not supported 1853 */ 1854 1855static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, 1856 const u8 *data, int clen) 1857{ 1858 u8 buf[1]; 1859 1860 switch (command) { 1861 case CMD_CLD: { 1862 struct gsm_dlci *dlci = gsm->dlci[0]; 1863 /* Modem wishes to close down */ 1864 if (dlci) { 1865 dlci->dead = true; 1866 gsm->dead = true; 1867 gsm_dlci_begin_close(dlci); 1868 } 1869 } 1870 break; 1871 case CMD_TEST: 1872 /* Modem wishes to test, reply with the data */ 1873 gsm_control_reply(gsm, CMD_TEST, data, clen); 1874 break; 1875 case CMD_FCON: 1876 /* Modem can accept data again */ 1877 gsm->constipated = false; 1878 gsm_control_reply(gsm, CMD_FCON, NULL, 0); 1879 /* Kick the link in case it is idling */ 1880 gsmld_write_trigger(gsm); 1881 break; 1882 case CMD_FCOFF: 1883 /* Modem wants us to STFU */ 1884 gsm->constipated = true; 1885 gsm_control_reply(gsm, CMD_FCOFF, NULL, 0); 1886 break; 1887 case CMD_MSC: 1888 /* Out of band modem line change indicator for a DLCI */ 1889 gsm_control_modem(gsm, data, clen); 1890 break; 1891 case CMD_RLS: 1892 /* Out of band error reception for a DLCI */ 1893 gsm_control_rls(gsm, data, clen); 1894 break; 1895 case CMD_PSC: 1896 /* Modem wishes to enter power saving state */ 1897 gsm_control_reply(gsm, CMD_PSC, NULL, 0); 1898 break; 1899 /* Optional commands */ 1900 case CMD_PN: 1901 /* Modem sends a parameter negotiation command */ 1902 gsm_control_negotiation(gsm, 1, data, clen); 1903 break; 1904 /* Optional unsupported commands */ 1905 case CMD_RPN: /* Remote port negotiation */ 1906 case CMD_SNC: /* Service negotiation command */ 1907 gsm->unsupported++; 1908 fallthrough; 1909 default: 1910 /* Reply to bad commands with an NSC */ 1911 buf[0] = command; 1912 gsm_control_reply(gsm, CMD_NSC, buf, 1); 1913 break; 1914 } 1915} 1916 1917/** 1918 * gsm_control_response - process a response to our control 1919 * @gsm: our GSM mux 1920 * @command: the command (response) EA 1921 * @data: data beyond the command/length EA 1922 * @clen: length 1923 * 1924 * Process a response to an outstanding command. We only allow a single 1925 * control message in flight so this is fairly easy. All the clean up 1926 * is done by the caller, we just update the fields, flag it as done 1927 * and return 1928 */ 1929 1930static void gsm_control_response(struct gsm_mux *gsm, unsigned int command, 1931 const u8 *data, int clen) 1932{ 1933 struct gsm_control *ctrl; 1934 struct gsm_dlci *dlci; 1935 unsigned long flags; 1936 1937 spin_lock_irqsave(&gsm->control_lock, flags); 1938 1939 ctrl = gsm->pending_cmd; 1940 dlci = gsm->dlci[0]; 1941 command |= 1; 1942 /* Does the reply match our command */ 1943 if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) { 1944 /* Our command was replied to, kill the retry timer */ 1945 timer_delete(&gsm->t2_timer); 1946 gsm->pending_cmd = NULL; 1947 /* Rejected by the other end */ 1948 if (command == CMD_NSC) 1949 ctrl->error = -EOPNOTSUPP; 1950 ctrl->done = 1; 1951 wake_up(&gsm->event); 1952 /* Or did we receive the PN response to our PN command */ 1953 } else if (command == CMD_PN) { 1954 gsm_control_negotiation(gsm, 0, data, clen); 1955 /* Or did we receive the TEST response to our TEST command */ 1956 } else if (command == CMD_TEST && clen == 1 && *data == gsm->ka_num) { 1957 gsm->ka_retries = -1; /* trigger new keep-alive message */ 1958 if (dlci && !dlci->dead) 1959 mod_timer(&gsm->ka_timer, jiffies + gsm->keep_alive * HZ / 100); 1960 } 1961 spin_unlock_irqrestore(&gsm->control_lock, flags); 1962} 1963 1964/** 1965 * gsm_control_keep_alive - check timeout or start keep-alive 1966 * @t: timer contained in our gsm object 1967 * 1968 * Called off the keep-alive timer expiry signaling that our link 1969 * partner is not responding anymore. Link will be closed. 1970 * This is also called to startup our timer. 1971 */ 1972 1973static void gsm_control_keep_alive(struct timer_list *t) 1974{ 1975 struct gsm_mux *gsm = timer_container_of(gsm, t, ka_timer); 1976 unsigned long flags; 1977 1978 spin_lock_irqsave(&gsm->control_lock, flags); 1979 if (gsm->ka_num && gsm->ka_retries == 0) { 1980 /* Keep-alive expired -> close the link */ 1981 if (debug & DBG_ERRORS) 1982 pr_debug("%s keep-alive timed out\n", __func__); 1983 spin_unlock_irqrestore(&gsm->control_lock, flags); 1984 if (gsm->dlci[0]) 1985 gsm_dlci_begin_close(gsm->dlci[0]); 1986 return; 1987 } else if (gsm->keep_alive && gsm->dlci[0] && !gsm->dlci[0]->dead) { 1988 if (gsm->ka_retries > 0) { 1989 /* T2 expired for keep-alive -> resend */ 1990 gsm->ka_retries--; 1991 } else { 1992 /* Start keep-alive timer */ 1993 gsm->ka_num++; 1994 if (!gsm->ka_num) 1995 gsm->ka_num++; 1996 gsm->ka_retries = (signed int)gsm->n2; 1997 } 1998 gsm_control_command(gsm, CMD_TEST, &gsm->ka_num, 1999 sizeof(gsm->ka_num)); 2000 mod_timer(&gsm->ka_timer, 2001 jiffies + gsm->t2 * HZ / 100); 2002 } 2003 spin_unlock_irqrestore(&gsm->control_lock, flags); 2004} 2005 2006/** 2007 * gsm_control_transmit - send control packet 2008 * @gsm: gsm mux 2009 * @ctrl: frame to send 2010 * 2011 * Send out a pending control command (called under control lock) 2012 */ 2013 2014static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl) 2015{ 2016 gsm_control_command(gsm, ctrl->cmd, ctrl->data, ctrl->len); 2017} 2018 2019/** 2020 * gsm_control_retransmit - retransmit a control frame 2021 * @t: timer contained in our gsm object 2022 * 2023 * Called off the T2 timer expiry in order to retransmit control frames 2024 * that have been lost in the system somewhere. The control_lock protects 2025 * us from colliding with another sender or a receive completion event. 2026 * In that situation the timer may still occur in a small window but 2027 * gsm->pending_cmd will be NULL and we just let the timer expire. 2028 */ 2029 2030static void gsm_control_retransmit(struct timer_list *t) 2031{ 2032 struct gsm_mux *gsm = timer_container_of(gsm, t, t2_timer); 2033 struct gsm_control *ctrl; 2034 unsigned long flags; 2035 spin_lock_irqsave(&gsm->control_lock, flags); 2036 ctrl = gsm->pending_cmd; 2037 if (ctrl) { 2038 if (gsm->cretries == 0 || !gsm->dlci[0] || gsm->dlci[0]->dead) { 2039 gsm->pending_cmd = NULL; 2040 ctrl->error = -ETIMEDOUT; 2041 ctrl->done = 1; 2042 spin_unlock_irqrestore(&gsm->control_lock, flags); 2043 wake_up(&gsm->event); 2044 return; 2045 } 2046 gsm->cretries--; 2047 gsm_control_transmit(gsm, ctrl); 2048 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); 2049 } 2050 spin_unlock_irqrestore(&gsm->control_lock, flags); 2051} 2052 2053/** 2054 * gsm_control_send - send a control frame on DLCI 0 2055 * @gsm: the GSM channel 2056 * @command: command to send including CR bit 2057 * @data: bytes of data (must be kmalloced) 2058 * @clen: length of the block to send 2059 * 2060 * Queue and dispatch a control command. Only one command can be 2061 * active at a time. In theory more can be outstanding but the matching 2062 * gets really complicated so for now stick to one outstanding. 2063 */ 2064 2065static struct gsm_control *gsm_control_send(struct gsm_mux *gsm, 2066 unsigned int command, u8 *data, int clen) 2067{ 2068 struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control), 2069 GFP_ATOMIC); 2070 unsigned long flags; 2071 if (ctrl == NULL) 2072 return NULL; 2073retry: 2074 wait_event(gsm->event, gsm->pending_cmd == NULL); 2075 spin_lock_irqsave(&gsm->control_lock, flags); 2076 if (gsm->pending_cmd != NULL) { 2077 spin_unlock_irqrestore(&gsm->control_lock, flags); 2078 goto retry; 2079 } 2080 ctrl->cmd = command; 2081 ctrl->data = data; 2082 ctrl->len = clen; 2083 gsm->pending_cmd = ctrl; 2084 2085 /* If DLCI0 is in ADM mode skip retries, it won't respond */ 2086 if (gsm->dlci[0]->mode == DLCI_MODE_ADM) 2087 gsm->cretries = 0; 2088 else 2089 gsm->cretries = gsm->n2; 2090 2091 mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); 2092 gsm_control_transmit(gsm, ctrl); 2093 spin_unlock_irqrestore(&gsm->control_lock, flags); 2094 return ctrl; 2095} 2096 2097/** 2098 * gsm_control_wait - wait for a control to finish 2099 * @gsm: GSM mux 2100 * @control: control we are waiting on 2101 * 2102 * Waits for the control to complete or time out. Frees any used 2103 * resources and returns 0 for success, or an error if the remote 2104 * rejected or ignored the request. 2105 */ 2106 2107static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control) 2108{ 2109 int err; 2110 wait_event(gsm->event, control->done == 1); 2111 err = control->error; 2112 kfree(control); 2113 return err; 2114} 2115 2116 2117/* 2118 * DLCI level handling: Needs krefs 2119 */ 2120 2121/* 2122 * State transitions and timers 2123 */ 2124 2125/** 2126 * gsm_dlci_close - a DLCI has closed 2127 * @dlci: DLCI that closed 2128 * 2129 * Perform processing when moving a DLCI into closed state. If there 2130 * is an attached tty this is hung up 2131 */ 2132 2133static void gsm_dlci_close(struct gsm_dlci *dlci) 2134{ 2135 timer_delete(&dlci->t1); 2136 if (debug & DBG_ERRORS) 2137 pr_debug("DLCI %d goes closed.\n", dlci->addr); 2138 dlci->state = DLCI_CLOSED; 2139 /* Prevent us from sending data before the link is up again */ 2140 dlci->constipated = true; 2141 if (dlci->addr != 0) { 2142 tty_port_tty_hangup(&dlci->port, false); 2143 gsm_dlci_clear_queues(dlci->gsm, dlci); 2144 /* Ensure that gsmtty_open() can return. */ 2145 tty_port_set_initialized(&dlci->port, false); 2146 wake_up_interruptible(&dlci->port.open_wait); 2147 } else { 2148 timer_delete(&dlci->gsm->ka_timer); 2149 dlci->gsm->dead = true; 2150 } 2151 /* A DLCI 0 close is a MUX termination so we need to kick that 2152 back to userspace somehow */ 2153 gsm_dlci_data_kick(dlci); 2154 wake_up_all(&dlci->gsm->event); 2155} 2156 2157/** 2158 * gsm_dlci_open - a DLCI has opened 2159 * @dlci: DLCI that opened 2160 * 2161 * Perform processing when moving a DLCI into open state. 2162 */ 2163 2164static void gsm_dlci_open(struct gsm_dlci *dlci) 2165{ 2166 struct gsm_mux *gsm = dlci->gsm; 2167 2168 /* Note that SABM UA .. SABM UA first UA lost can mean that we go 2169 open -> open */ 2170 timer_delete(&dlci->t1); 2171 /* This will let a tty open continue */ 2172 dlci->state = DLCI_OPEN; 2173 dlci->constipated = false; 2174 if (debug & DBG_ERRORS) 2175 pr_debug("DLCI %d goes open.\n", dlci->addr); 2176 /* Send current modem state */ 2177 if (dlci->addr) { 2178 gsm_modem_send_initial_msc(dlci); 2179 } else { 2180 /* Start keep-alive control */ 2181 gsm->ka_num = 0; 2182 gsm->ka_retries = -1; 2183 mod_timer(&gsm->ka_timer, 2184 jiffies + gsm->keep_alive * HZ / 100); 2185 } 2186 gsm_dlci_data_kick(dlci); 2187 wake_up(&dlci->gsm->event); 2188} 2189 2190/** 2191 * gsm_dlci_negotiate - start parameter negotiation 2192 * @dlci: DLCI to open 2193 * 2194 * Starts the parameter negotiation for the new DLCI. This needs to be done 2195 * before the DLCI initialized the channel via SABM. 2196 */ 2197static int gsm_dlci_negotiate(struct gsm_dlci *dlci) 2198{ 2199 struct gsm_mux *gsm = dlci->gsm; 2200 struct gsm_dlci_param_bits params; 2201 int ret; 2202 2203 ret = gsm_encode_params(dlci, ¶ms); 2204 if (ret != 0) 2205 return ret; 2206 2207 /* We cannot asynchronous wait for the command response with 2208 * gsm_command() and gsm_control_wait() at this point. 2209 */ 2210 ret = gsm_control_command(gsm, CMD_PN, (const u8 *)¶ms, 2211 sizeof(params)); 2212 2213 return ret; 2214} 2215 2216/** 2217 * gsm_dlci_t1 - T1 timer expiry 2218 * @t: timer contained in the DLCI that opened 2219 * 2220 * The T1 timer handles retransmits of control frames (essentially of 2221 * SABM and DISC). We resend the command until the retry count runs out 2222 * in which case an opening port goes back to closed and a closing port 2223 * is simply put into closed state (any further frames from the other 2224 * end will get a DM response) 2225 * 2226 * Some control dlci can stay in ADM mode with other dlci working just 2227 * fine. In that case we can just keep the control dlci open after the 2228 * DLCI_OPENING receives DM. 2229 */ 2230 2231static void gsm_dlci_t1(struct timer_list *t) 2232{ 2233 struct gsm_dlci *dlci = timer_container_of(dlci, t, t1); 2234 struct gsm_mux *gsm = dlci->gsm; 2235 2236 switch (dlci->state) { 2237 case DLCI_CONFIGURE: 2238 if (dlci->retries && gsm_dlci_negotiate(dlci) == 0) { 2239 dlci->retries--; 2240 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 2241 } else { 2242 gsm->open_error++; 2243 gsm_dlci_begin_close(dlci); /* prevent half open link */ 2244 } 2245 break; 2246 case DLCI_OPENING: 2247 if (!dlci->addr && gsm->control == (DM | PF)) { 2248 if (debug & DBG_ERRORS) 2249 pr_info("DLCI 0 opening in ADM mode.\n"); 2250 dlci->mode = DLCI_MODE_ADM; 2251 gsm_dlci_open(dlci); 2252 } else if (dlci->retries) { 2253 if (!dlci->addr || !gsm->dlci[0] || 2254 gsm->dlci[0]->state != DLCI_OPENING) { 2255 dlci->retries--; 2256 gsm_command(dlci->gsm, dlci->addr, SABM|PF); 2257 } 2258 2259 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 2260 } else { 2261 gsm->open_error++; 2262 gsm_dlci_begin_close(dlci); /* prevent half open link */ 2263 } 2264 2265 break; 2266 case DLCI_CLOSING: 2267 if (dlci->retries) { 2268 dlci->retries--; 2269 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 2270 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 2271 } else 2272 gsm_dlci_close(dlci); 2273 break; 2274 default: 2275 pr_debug("%s: unhandled state: %d\n", __func__, dlci->state); 2276 break; 2277 } 2278} 2279 2280/** 2281 * gsm_dlci_begin_open - start channel open procedure 2282 * @dlci: DLCI to open 2283 * 2284 * Commence opening a DLCI from the Linux side. We issue SABM messages 2285 * to the modem which should then reply with a UA or ADM, at which point 2286 * we will move into open state. Opening is done asynchronously with retry 2287 * running off timers and the responses. 2288 * Parameter negotiation is performed before SABM if required. 2289 */ 2290 2291static void gsm_dlci_begin_open(struct gsm_dlci *dlci) 2292{ 2293 struct gsm_mux *gsm = dlci ? dlci->gsm : NULL; 2294 bool need_pn = false; 2295 2296 if (!gsm) 2297 return; 2298 2299 if (dlci->addr != 0) { 2300 if (gsm->adaption != 1 || gsm->adaption != dlci->adaption) 2301 need_pn = true; 2302 if (dlci->prio != (roundup(dlci->addr + 1, 8) - 1)) 2303 need_pn = true; 2304 if (gsm->ftype != dlci->ftype) 2305 need_pn = true; 2306 } 2307 2308 switch (dlci->state) { 2309 case DLCI_CLOSED: 2310 case DLCI_WAITING_CONFIG: 2311 case DLCI_CLOSING: 2312 dlci->retries = gsm->n2; 2313 if (!need_pn) { 2314 dlci->state = DLCI_OPENING; 2315 if (!dlci->addr || !gsm->dlci[0] || 2316 gsm->dlci[0]->state != DLCI_OPENING) 2317 gsm_command(gsm, dlci->addr, SABM|PF); 2318 } else { 2319 /* Configure DLCI before setup */ 2320 dlci->state = DLCI_CONFIGURE; 2321 if (gsm_dlci_negotiate(dlci) != 0) { 2322 gsm_dlci_close(dlci); 2323 return; 2324 } 2325 } 2326 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 2327 break; 2328 default: 2329 break; 2330 } 2331} 2332 2333/** 2334 * gsm_dlci_set_opening - change state to opening 2335 * @dlci: DLCI to open 2336 * 2337 * Change internal state to wait for DLCI open from initiator side. 2338 * We set off timers and responses upon reception of an SABM. 2339 */ 2340static void gsm_dlci_set_opening(struct gsm_dlci *dlci) 2341{ 2342 switch (dlci->state) { 2343 case DLCI_CLOSED: 2344 case DLCI_WAITING_CONFIG: 2345 case DLCI_CLOSING: 2346 dlci->state = DLCI_OPENING; 2347 break; 2348 default: 2349 break; 2350 } 2351} 2352 2353/** 2354 * gsm_dlci_set_wait_config - wait for channel configuration 2355 * @dlci: DLCI to configure 2356 * 2357 * Wait for a DLCI configuration from the application. 2358 */ 2359static void gsm_dlci_set_wait_config(struct gsm_dlci *dlci) 2360{ 2361 switch (dlci->state) { 2362 case DLCI_CLOSED: 2363 case DLCI_CLOSING: 2364 dlci->state = DLCI_WAITING_CONFIG; 2365 break; 2366 default: 2367 break; 2368 } 2369} 2370 2371/** 2372 * gsm_dlci_begin_close - start channel open procedure 2373 * @dlci: DLCI to open 2374 * 2375 * Commence closing a DLCI from the Linux side. We issue DISC messages 2376 * to the modem which should then reply with a UA, at which point we 2377 * will move into closed state. Closing is done asynchronously with retry 2378 * off timers. We may also receive a DM reply from the other end which 2379 * indicates the channel was already closed. 2380 */ 2381 2382static void gsm_dlci_begin_close(struct gsm_dlci *dlci) 2383{ 2384 struct gsm_mux *gsm = dlci->gsm; 2385 if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING) 2386 return; 2387 dlci->retries = gsm->n2; 2388 dlci->state = DLCI_CLOSING; 2389 gsm_command(dlci->gsm, dlci->addr, DISC|PF); 2390 mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); 2391 wake_up_interruptible(&gsm->event); 2392} 2393 2394/** 2395 * gsm_dlci_data - data arrived 2396 * @dlci: channel 2397 * @data: block of bytes received 2398 * @clen: length of received block 2399 * 2400 * A UI or UIH frame has arrived which contains data for a channel 2401 * other than the control channel. If the relevant virtual tty is 2402 * open we shovel the bits down it, if not we drop them. 2403 */ 2404 2405static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen) 2406{ 2407 /* krefs .. */ 2408 struct tty_port *port = &dlci->port; 2409 struct tty_struct *tty; 2410 unsigned int modem = 0; 2411 int len; 2412 2413 if (debug & DBG_TTY) 2414 pr_debug("%d bytes for tty\n", clen); 2415 switch (dlci->adaption) { 2416 /* Unsupported types */ 2417 case 4: /* Packetised interruptible data */ 2418 break; 2419 case 3: /* Packetised uininterruptible voice/data */ 2420 break; 2421 case 2: /* Asynchronous serial with line state in each frame */ 2422 len = gsm_read_ea_val(&modem, data, clen); 2423 if (len < 1) 2424 return; 2425 tty = tty_port_tty_get(port); 2426 if (tty) { 2427 gsm_process_modem(tty, dlci, modem, len); 2428 tty_wakeup(tty); 2429 tty_kref_put(tty); 2430 } 2431 /* Skip processed modem data */ 2432 data += len; 2433 clen -= len; 2434 fallthrough; 2435 case 1: /* Line state will go via DLCI 0 controls only */ 2436 default: 2437 tty_insert_flip_string(port, data, clen); 2438 tty_flip_buffer_push(port); 2439 } 2440} 2441 2442/** 2443 * gsm_dlci_command - data arrived on control channel 2444 * @dlci: channel 2445 * @data: block of bytes received 2446 * @len: length of received block 2447 * 2448 * A UI or UIH frame has arrived which contains data for DLCI 0 the 2449 * control channel. This should contain a command EA followed by 2450 * control data bytes. The command EA contains a command/response bit 2451 * and we divide up the work accordingly. 2452 */ 2453 2454static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len) 2455{ 2456 /* See what command is involved */ 2457 unsigned int command = 0; 2458 unsigned int clen = 0; 2459 unsigned int dlen; 2460 2461 /* read the command */ 2462 dlen = gsm_read_ea_val(&command, data, len); 2463 len -= dlen; 2464 data += dlen; 2465 2466 /* read any control data */ 2467 dlen = gsm_read_ea_val(&clen, data, len); 2468 len -= dlen; 2469 data += dlen; 2470 2471 /* Malformed command? */ 2472 if (clen > len) { 2473 dlci->gsm->malformed++; 2474 return; 2475 } 2476 2477 if (command & 1) 2478 gsm_control_message(dlci->gsm, command, data, clen); 2479 else 2480 gsm_control_response(dlci->gsm, command, data, clen); 2481} 2482 2483/** 2484 * gsm_kick_timer - transmit if possible 2485 * @t: timer contained in our gsm object 2486 * 2487 * Transmit data from DLCIs if the queue is empty. We can't rely on 2488 * a tty wakeup except when we filled the pipe so we need to fire off 2489 * new data ourselves in other cases. 2490 */ 2491static void gsm_kick_timer(struct timer_list *t) 2492{ 2493 struct gsm_mux *gsm = timer_container_of(gsm, t, kick_timer); 2494 unsigned long flags; 2495 int sent = 0; 2496 2497 spin_lock_irqsave(&gsm->tx_lock, flags); 2498 /* If we have nothing running then we need to fire up */ 2499 if (gsm->tx_bytes < TX_THRESH_LO) 2500 sent = gsm_dlci_data_sweep(gsm); 2501 spin_unlock_irqrestore(&gsm->tx_lock, flags); 2502 2503 if (sent && debug & DBG_DATA) 2504 pr_info("%s TX queue stalled\n", __func__); 2505} 2506 2507/** 2508 * gsm_dlci_copy_config_values - copy DLCI configuration 2509 * @dlci: source DLCI 2510 * @dc: configuration structure to fill 2511 */ 2512static void gsm_dlci_copy_config_values(struct gsm_dlci *dlci, struct gsm_dlci_config *dc) 2513{ 2514 memset(dc, 0, sizeof(*dc)); 2515 dc->channel = (u32)dlci->addr; 2516 dc->adaption = (u32)dlci->adaption; 2517 dc->mtu = (u32)dlci->mtu; 2518 dc->priority = (u32)dlci->prio; 2519 if (dlci->ftype == UIH) 2520 dc->i = 1; 2521 else 2522 dc->i = 2; 2523 dc->k = (u32)dlci->k; 2524} 2525 2526/** 2527 * gsm_dlci_config - configure DLCI from configuration 2528 * @dlci: DLCI to configure 2529 * @dc: DLCI configuration 2530 * @open: open DLCI after configuration? 2531 */ 2532static int gsm_dlci_config(struct gsm_dlci *dlci, struct gsm_dlci_config *dc, int open) 2533{ 2534 struct gsm_mux *gsm; 2535 bool need_restart = false; 2536 bool need_open = false; 2537 unsigned int i; 2538 2539 /* 2540 * Check that userspace doesn't put stuff in here to prevent breakages 2541 * in the future. 2542 */ 2543 for (i = 0; i < ARRAY_SIZE(dc->reserved); i++) 2544 if (dc->reserved[i]) 2545 return -EINVAL; 2546 2547 if (!dlci) 2548 return -EINVAL; 2549 gsm = dlci->gsm; 2550 2551 /* Stuff we don't support yet - I frame transport */ 2552 if (dc->adaption != 1 && dc->adaption != 2) 2553 return -EOPNOTSUPP; 2554 if (dc->mtu > MAX_MTU || dc->mtu < MIN_MTU || dc->mtu > gsm->mru) 2555 return -EINVAL; 2556 if (dc->priority >= 64) 2557 return -EINVAL; 2558 if (dc->i == 0 || dc->i > 2) /* UIH and UI only */ 2559 return -EINVAL; 2560 if (dc->k > 7) 2561 return -EINVAL; 2562 if (dc->flags & ~GSM_FL_RESTART) /* allow future extensions */ 2563 return -EINVAL; 2564 2565 /* 2566 * See what is needed for reconfiguration 2567 */ 2568 /* Framing fields */ 2569 if (dc->adaption != dlci->adaption) 2570 need_restart = true; 2571 if (dc->mtu != dlci->mtu) 2572 need_restart = true; 2573 if (dc->i != dlci->ftype) 2574 need_restart = true; 2575 /* Requires care */ 2576 if (dc->priority != dlci->prio) 2577 need_restart = true; 2578 if (dc->flags & GSM_FL_RESTART) 2579 need_restart = true; 2580 2581 if ((open && gsm->wait_config) || need_restart) 2582 need_open = true; 2583 if (dlci->state == DLCI_WAITING_CONFIG) { 2584 need_restart = false; 2585 need_open = true; 2586 } 2587 2588 /* 2589 * Close down what is needed, restart and initiate the new 2590 * configuration. 2591 */ 2592 if (need_restart) { 2593 gsm_dlci_begin_close(dlci); 2594 wait_event_interruptible(gsm->event, dlci->state == DLCI_CLOSED); 2595 if (signal_pending(current)) 2596 return -EINTR; 2597 } 2598 /* 2599 * Setup the new configuration values 2600 */ 2601 dlci->adaption = (int)dc->adaption; 2602 2603 if (dc->mtu) 2604 dlci->mtu = (unsigned int)dc->mtu; 2605 else 2606 dlci->mtu = gsm->mtu; 2607 2608 if (dc->priority) 2609 dlci->prio = (u8)dc->priority; 2610 else 2611 dlci->prio = roundup(dlci->addr + 1, 8) - 1; 2612 2613 if (dc->i == 1) 2614 dlci->ftype = UIH; 2615 else if (dc->i == 2) 2616 dlci->ftype = UI; 2617 2618 if (dc->k) 2619 dlci->k = (u8)dc->k; 2620 else 2621 dlci->k = gsm->k; 2622 2623 if (need_open) { 2624 if (gsm->initiator) 2625 gsm_dlci_begin_open(dlci); 2626 else 2627 gsm_dlci_set_opening(dlci); 2628 } 2629 2630 return 0; 2631} 2632 2633/* 2634 * Allocate/Free DLCI channels 2635 */ 2636 2637/** 2638 * gsm_dlci_alloc - allocate a DLCI 2639 * @gsm: GSM mux 2640 * @addr: address of the DLCI 2641 * 2642 * Allocate and install a new DLCI object into the GSM mux. 2643 * 2644 * FIXME: review locking races 2645 */ 2646 2647static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr) 2648{ 2649 struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC); 2650 if (dlci == NULL) 2651 return NULL; 2652 spin_lock_init(&dlci->lock); 2653 mutex_init(&dlci->mutex); 2654 if (kfifo_alloc(&dlci->fifo, TX_SIZE, GFP_KERNEL) < 0) { 2655 kfree(dlci); 2656 return NULL; 2657 } 2658 2659 skb_queue_head_init(&dlci->skb_list); 2660 timer_setup(&dlci->t1, gsm_dlci_t1, 0); 2661 tty_port_init(&dlci->port); 2662 dlci->port.ops = &gsm_port_ops; 2663 dlci->gsm = gsm; 2664 dlci->addr = addr; 2665 dlci->adaption = gsm->adaption; 2666 dlci->mtu = gsm->mtu; 2667 if (addr == 0) 2668 dlci->prio = 0; 2669 else 2670 dlci->prio = roundup(addr + 1, 8) - 1; 2671 dlci->ftype = gsm->ftype; 2672 dlci->k = gsm->k; 2673 dlci->state = DLCI_CLOSED; 2674 if (addr) { 2675 dlci->data = gsm_dlci_data; 2676 /* Prevent us from sending data before the link is up */ 2677 dlci->constipated = true; 2678 } else { 2679 dlci->data = gsm_dlci_command; 2680 } 2681 gsm->dlci[addr] = dlci; 2682 return dlci; 2683} 2684 2685/** 2686 * gsm_dlci_free - free DLCI 2687 * @port: tty port for DLCI to free 2688 * 2689 * Free up a DLCI. 2690 * 2691 * Can sleep. 2692 */ 2693static void gsm_dlci_free(struct tty_port *port) 2694{ 2695 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 2696 2697 timer_shutdown_sync(&dlci->t1); 2698 dlci->gsm->dlci[dlci->addr] = NULL; 2699 kfifo_free(&dlci->fifo); 2700 while ((dlci->skb = skb_dequeue(&dlci->skb_list))) 2701 dev_kfree_skb(dlci->skb); 2702 kfree(dlci); 2703} 2704 2705static inline void dlci_get(struct gsm_dlci *dlci) 2706{ 2707 tty_port_get(&dlci->port); 2708} 2709 2710static inline void dlci_put(struct gsm_dlci *dlci) 2711{ 2712 tty_port_put(&dlci->port); 2713} 2714 2715static void gsm_destroy_network(struct gsm_dlci *dlci); 2716 2717/** 2718 * gsm_dlci_release - release DLCI 2719 * @dlci: DLCI to destroy 2720 * 2721 * Release a DLCI. Actual free is deferred until either 2722 * mux is closed or tty is closed - whichever is last. 2723 * 2724 * Can sleep. 2725 */ 2726static void gsm_dlci_release(struct gsm_dlci *dlci) 2727{ 2728 struct tty_struct *tty = tty_port_tty_get(&dlci->port); 2729 if (tty) { 2730 mutex_lock(&dlci->mutex); 2731 gsm_destroy_network(dlci); 2732 mutex_unlock(&dlci->mutex); 2733 2734 /* We cannot use tty_hangup() because in tty_kref_put() the tty 2735 * driver assumes that the hangup queue is free and reuses it to 2736 * queue release_one_tty() -> NULL pointer panic in 2737 * process_one_work(). 2738 */ 2739 tty_vhangup(tty); 2740 2741 tty_port_tty_set(&dlci->port, NULL); 2742 tty_kref_put(tty); 2743 } 2744 dlci->state = DLCI_CLOSED; 2745 dlci_put(dlci); 2746} 2747 2748/* 2749 * LAPBish link layer logic 2750 */ 2751 2752/** 2753 * gsm_queue - a GSM frame is ready to process 2754 * @gsm: pointer to our gsm mux 2755 * 2756 * At this point in time a frame has arrived and been demangled from 2757 * the line encoding. All the differences between the encodings have 2758 * been handled below us and the frame is unpacked into the structures. 2759 * The fcs holds the header FCS but any data FCS must be added here. 2760 */ 2761 2762static void gsm_queue(struct gsm_mux *gsm) 2763{ 2764 struct gsm_dlci *dlci; 2765 u8 cr; 2766 int address; 2767 2768 if (gsm->fcs != GOOD_FCS) { 2769 gsm->bad_fcs++; 2770 if (debug & DBG_DATA) 2771 pr_debug("BAD FCS %02x\n", gsm->fcs); 2772 return; 2773 } 2774 address = gsm->address >> 1; 2775 if (address >= NUM_DLCI) 2776 goto invalid; 2777 2778 cr = gsm->address & 1; /* C/R bit */ 2779 cr ^= gsm->initiator ? 0 : 1; /* Flip so 1 always means command */ 2780 2781 gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len); 2782 2783 dlci = gsm->dlci[address]; 2784 2785 switch (gsm->control) { 2786 case SABM|PF: 2787 if (cr == 1) { 2788 gsm->open_error++; 2789 goto invalid; 2790 } 2791 if (dlci == NULL) 2792 dlci = gsm_dlci_alloc(gsm, address); 2793 if (dlci == NULL) { 2794 gsm->open_error++; 2795 return; 2796 } 2797 if (dlci->dead) 2798 gsm_response(gsm, address, DM|PF); 2799 else { 2800 gsm_response(gsm, address, UA|PF); 2801 gsm_dlci_open(dlci); 2802 } 2803 break; 2804 case DISC|PF: 2805 if (cr == 1) 2806 goto invalid; 2807 if (dlci == NULL || dlci->state == DLCI_CLOSED) { 2808 gsm_response(gsm, address, DM|PF); 2809 return; 2810 } 2811 /* Real close complete */ 2812 gsm_response(gsm, address, UA|PF); 2813 gsm_dlci_close(dlci); 2814 break; 2815 case UA|PF: 2816 if (cr == 0 || dlci == NULL) 2817 break; 2818 switch (dlci->state) { 2819 case DLCI_CLOSING: 2820 gsm_dlci_close(dlci); 2821 break; 2822 case DLCI_OPENING: 2823 gsm_dlci_open(dlci); 2824 break; 2825 default: 2826 pr_debug("%s: unhandled state: %d\n", __func__, 2827 dlci->state); 2828 break; 2829 } 2830 break; 2831 case DM: /* DM can be valid unsolicited */ 2832 case DM|PF: 2833 if (cr) 2834 goto invalid; 2835 if (dlci == NULL) 2836 return; 2837 gsm_dlci_close(dlci); 2838 break; 2839 case UI: 2840 case UI|PF: 2841 case UIH: 2842 case UIH|PF: 2843 if (dlci == NULL || dlci->state != DLCI_OPEN) { 2844 gsm_response(gsm, address, DM|PF); 2845 return; 2846 } 2847 dlci->data(dlci, gsm->buf, gsm->len); 2848 break; 2849 default: 2850 goto invalid; 2851 } 2852 return; 2853invalid: 2854 gsm->malformed++; 2855 return; 2856} 2857 2858/** 2859 * gsm0_receive_state_check_and_fix - check and correct receive state 2860 * @gsm: gsm data for this ldisc instance 2861 * 2862 * Ensures that the current receive state is valid for basic option mode. 2863 */ 2864 2865static void gsm0_receive_state_check_and_fix(struct gsm_mux *gsm) 2866{ 2867 switch (gsm->state) { 2868 case GSM_SEARCH: 2869 case GSM0_ADDRESS: 2870 case GSM0_CONTROL: 2871 case GSM0_LEN0: 2872 case GSM0_LEN1: 2873 case GSM0_DATA: 2874 case GSM0_FCS: 2875 case GSM0_SSOF: 2876 break; 2877 default: 2878 gsm->state = GSM_SEARCH; 2879 break; 2880 } 2881} 2882 2883/** 2884 * gsm0_receive - perform processing for non-transparency 2885 * @gsm: gsm data for this ldisc instance 2886 * @c: character 2887 * 2888 * Receive bytes in gsm mode 0 2889 */ 2890 2891static void gsm0_receive(struct gsm_mux *gsm, u8 c) 2892{ 2893 unsigned int len; 2894 2895 gsm0_receive_state_check_and_fix(gsm); 2896 switch (gsm->state) { 2897 case GSM_SEARCH: /* SOF marker */ 2898 if (c == GSM0_SOF) { 2899 gsm->state = GSM0_ADDRESS; 2900 gsm->address = 0; 2901 gsm->len = 0; 2902 gsm->fcs = INIT_FCS; 2903 } 2904 break; 2905 case GSM0_ADDRESS: /* Address EA */ 2906 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 2907 if (gsm_read_ea(&gsm->address, c)) 2908 gsm->state = GSM0_CONTROL; 2909 break; 2910 case GSM0_CONTROL: /* Control Byte */ 2911 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 2912 gsm->control = c; 2913 gsm->state = GSM0_LEN0; 2914 break; 2915 case GSM0_LEN0: /* Length EA */ 2916 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 2917 if (gsm_read_ea(&gsm->len, c)) { 2918 if (gsm->len > gsm->mru) { 2919 gsm->bad_size++; 2920 gsm->state = GSM_SEARCH; 2921 break; 2922 } 2923 gsm->count = 0; 2924 if (!gsm->len) 2925 gsm->state = GSM0_FCS; 2926 else 2927 gsm->state = GSM0_DATA; 2928 break; 2929 } 2930 gsm->state = GSM0_LEN1; 2931 break; 2932 case GSM0_LEN1: 2933 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 2934 len = c; 2935 gsm->len |= len << 7; 2936 if (gsm->len > gsm->mru) { 2937 gsm->bad_size++; 2938 gsm->state = GSM_SEARCH; 2939 break; 2940 } 2941 gsm->count = 0; 2942 if (!gsm->len) 2943 gsm->state = GSM0_FCS; 2944 else 2945 gsm->state = GSM0_DATA; 2946 break; 2947 case GSM0_DATA: /* Data */ 2948 gsm->buf[gsm->count++] = c; 2949 if (gsm->count >= MAX_MRU) { 2950 gsm->bad_size++; 2951 gsm->state = GSM_SEARCH; 2952 } else if (gsm->count >= gsm->len) { 2953 /* Calculate final FCS for UI frames over all data */ 2954 if ((gsm->control & ~PF) != UIH) { 2955 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, 2956 gsm->count); 2957 } 2958 gsm->state = GSM0_FCS; 2959 } 2960 break; 2961 case GSM0_FCS: /* FCS follows the packet */ 2962 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 2963 gsm->state = GSM0_SSOF; 2964 break; 2965 case GSM0_SSOF: 2966 gsm->state = GSM_SEARCH; 2967 if (c == GSM0_SOF) 2968 gsm_queue(gsm); 2969 else 2970 gsm->bad_size++; 2971 break; 2972 default: 2973 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state); 2974 break; 2975 } 2976} 2977 2978/** 2979 * gsm1_receive_state_check_and_fix - check and correct receive state 2980 * @gsm: gsm data for this ldisc instance 2981 * 2982 * Ensures that the current receive state is valid for advanced option mode. 2983 */ 2984 2985static void gsm1_receive_state_check_and_fix(struct gsm_mux *gsm) 2986{ 2987 switch (gsm->state) { 2988 case GSM_SEARCH: 2989 case GSM1_START: 2990 case GSM1_ADDRESS: 2991 case GSM1_CONTROL: 2992 case GSM1_DATA: 2993 case GSM1_OVERRUN: 2994 break; 2995 default: 2996 gsm->state = GSM_SEARCH; 2997 break; 2998 } 2999} 3000 3001/** 3002 * gsm1_receive - perform processing for non-transparency 3003 * @gsm: gsm data for this ldisc instance 3004 * @c: character 3005 * 3006 * Receive bytes in mode 1 (Advanced option) 3007 */ 3008 3009static void gsm1_receive(struct gsm_mux *gsm, u8 c) 3010{ 3011 gsm1_receive_state_check_and_fix(gsm); 3012 /* handle XON/XOFF */ 3013 if ((c & ISO_IEC_646_MASK) == XON) { 3014 gsm->constipated = true; 3015 return; 3016 } else if ((c & ISO_IEC_646_MASK) == XOFF) { 3017 gsm->constipated = false; 3018 /* Kick the link in case it is idling */ 3019 gsmld_write_trigger(gsm); 3020 return; 3021 } 3022 if (c == GSM1_SOF) { 3023 /* EOF is only valid in frame if we have got to the data state */ 3024 if (gsm->state == GSM1_DATA) { 3025 if (gsm->count < 1) { 3026 /* Missing FSC */ 3027 gsm->malformed++; 3028 gsm->state = GSM1_START; 3029 return; 3030 } 3031 /* Remove the FCS from data */ 3032 gsm->count--; 3033 if ((gsm->control & ~PF) != UIH) { 3034 /* Calculate final FCS for UI frames over all 3035 * data but FCS 3036 */ 3037 gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, 3038 gsm->count); 3039 } 3040 /* Add the FCS itself to test against GOOD_FCS */ 3041 gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]); 3042 gsm->len = gsm->count; 3043 gsm_queue(gsm); 3044 gsm->state = GSM1_START; 3045 return; 3046 } 3047 /* Any partial frame was a runt so go back to start */ 3048 if (gsm->state != GSM1_START) { 3049 if (gsm->state != GSM_SEARCH) 3050 gsm->malformed++; 3051 gsm->state = GSM1_START; 3052 } 3053 /* A SOF in GSM_START means we are still reading idling or 3054 framing bytes */ 3055 return; 3056 } 3057 3058 if (c == GSM1_ESCAPE) { 3059 gsm->escape = true; 3060 return; 3061 } 3062 3063 /* Only an unescaped SOF gets us out of GSM search */ 3064 if (gsm->state == GSM_SEARCH) 3065 return; 3066 3067 if (gsm->escape) { 3068 c ^= GSM1_ESCAPE_BITS; 3069 gsm->escape = false; 3070 } 3071 switch (gsm->state) { 3072 case GSM1_START: /* First byte after SOF */ 3073 gsm->address = 0; 3074 gsm->state = GSM1_ADDRESS; 3075 gsm->fcs = INIT_FCS; 3076 fallthrough; 3077 case GSM1_ADDRESS: /* Address continuation */ 3078 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 3079 if (gsm_read_ea(&gsm->address, c)) 3080 gsm->state = GSM1_CONTROL; 3081 break; 3082 case GSM1_CONTROL: /* Control Byte */ 3083 gsm->fcs = gsm_fcs_add(gsm->fcs, c); 3084 gsm->control = c; 3085 gsm->count = 0; 3086 gsm->state = GSM1_DATA; 3087 break; 3088 case GSM1_DATA: /* Data */ 3089 if (gsm->count > gsm->mru || gsm->count > MAX_MRU) { /* Allow one for the FCS */ 3090 gsm->state = GSM1_OVERRUN; 3091 gsm->bad_size++; 3092 } else 3093 gsm->buf[gsm->count++] = c; 3094 break; 3095 case GSM1_OVERRUN: /* Over-long - eg a dropped SOF */ 3096 break; 3097 default: 3098 pr_debug("%s: unhandled state: %d\n", __func__, gsm->state); 3099 break; 3100 } 3101} 3102 3103/** 3104 * gsm_error - handle tty error 3105 * @gsm: ldisc data 3106 * 3107 * Handle an error in the receipt of data for a frame. Currently we just 3108 * go back to hunting for a SOF. 3109 * 3110 * FIXME: better diagnostics ? 3111 */ 3112 3113static void gsm_error(struct gsm_mux *gsm) 3114{ 3115 gsm->state = GSM_SEARCH; 3116 gsm->io_error++; 3117} 3118 3119/** 3120 * gsm_cleanup_mux - generic GSM protocol cleanup 3121 * @gsm: our mux 3122 * @disc: disconnect link? 3123 * 3124 * Clean up the bits of the mux which are the same for all framing 3125 * protocols. Remove the mux from the mux table, stop all the timers 3126 * and then shut down each device hanging up the channels as we go. 3127 */ 3128 3129static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc) 3130{ 3131 int i; 3132 struct gsm_dlci *dlci; 3133 struct gsm_msg *txq, *ntxq; 3134 3135 gsm->dead = true; 3136 mutex_lock(&gsm->mutex); 3137 3138 dlci = gsm->dlci[0]; 3139 if (dlci) { 3140 if (disc && dlci->state != DLCI_CLOSED) { 3141 gsm_dlci_begin_close(dlci); 3142 wait_event(gsm->event, dlci->state == DLCI_CLOSED); 3143 } 3144 dlci->dead = true; 3145 } 3146 3147 /* Finish outstanding timers, making sure they are done */ 3148 timer_delete_sync(&gsm->kick_timer); 3149 timer_delete_sync(&gsm->t2_timer); 3150 timer_delete_sync(&gsm->ka_timer); 3151 3152 /* Finish writing to ldisc */ 3153 flush_work(&gsm->tx_work); 3154 3155 /* Free up any link layer users and finally the control channel */ 3156 if (gsm->has_devices) { 3157 gsm_unregister_devices(gsm_tty_driver, gsm->num); 3158 gsm->has_devices = false; 3159 } 3160 for (i = NUM_DLCI - 1; i >= 0; i--) 3161 if (gsm->dlci[i]) 3162 gsm_dlci_release(gsm->dlci[i]); 3163 mutex_unlock(&gsm->mutex); 3164 /* Now wipe the queues */ 3165 tty_ldisc_flush(gsm->tty); 3166 3167 guard(spinlock_irqsave)(&gsm->tx_lock); 3168 list_for_each_entry_safe(txq, ntxq, &gsm->tx_ctrl_list, list) 3169 kfree(txq); 3170 INIT_LIST_HEAD(&gsm->tx_ctrl_list); 3171 list_for_each_entry_safe(txq, ntxq, &gsm->tx_data_list, list) 3172 kfree(txq); 3173 INIT_LIST_HEAD(&gsm->tx_data_list); 3174} 3175 3176/** 3177 * gsm_activate_mux - generic GSM setup 3178 * @gsm: our mux 3179 * 3180 * Set up the bits of the mux which are the same for all framing 3181 * protocols. Add the mux to the mux table so it can be opened and 3182 * finally kick off connecting to DLCI 0 on the modem. 3183 */ 3184 3185static int gsm_activate_mux(struct gsm_mux *gsm) 3186{ 3187 struct gsm_dlci *dlci; 3188 int ret; 3189 3190 dlci = gsm_dlci_alloc(gsm, 0); 3191 if (dlci == NULL) 3192 return -ENOMEM; 3193 3194 if (gsm->encoding == GSM_BASIC_OPT) 3195 gsm->receive = gsm0_receive; 3196 else 3197 gsm->receive = gsm1_receive; 3198 3199 ret = gsm_register_devices(gsm_tty_driver, gsm->num); 3200 if (ret) 3201 return ret; 3202 3203 gsm->has_devices = true; 3204 gsm->dead = false; /* Tty opens are now permissible */ 3205 return 0; 3206} 3207 3208/** 3209 * gsm_free_mux - free up a mux 3210 * @gsm: mux to free 3211 * 3212 * Dispose of allocated resources for a dead mux 3213 */ 3214static void gsm_free_mux(struct gsm_mux *gsm) 3215{ 3216 int i; 3217 3218 for (i = 0; i < MAX_MUX; i++) { 3219 if (gsm == gsm_mux[i]) { 3220 gsm_mux[i] = NULL; 3221 break; 3222 } 3223 } 3224 mutex_destroy(&gsm->mutex); 3225 kfree(gsm->txframe); 3226 kfree(gsm->buf); 3227 kfree(gsm); 3228} 3229 3230/** 3231 * gsm_free_muxr - free up a mux 3232 * @ref: kreference to the mux to free 3233 * 3234 * Dispose of allocated resources for a dead mux 3235 */ 3236static void gsm_free_muxr(struct kref *ref) 3237{ 3238 struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref); 3239 gsm_free_mux(gsm); 3240} 3241 3242static inline void mux_get(struct gsm_mux *gsm) 3243{ 3244 unsigned long flags; 3245 3246 spin_lock_irqsave(&gsm_mux_lock, flags); 3247 kref_get(&gsm->ref); 3248 spin_unlock_irqrestore(&gsm_mux_lock, flags); 3249} 3250 3251static inline void mux_put(struct gsm_mux *gsm) 3252{ 3253 unsigned long flags; 3254 3255 spin_lock_irqsave(&gsm_mux_lock, flags); 3256 kref_put(&gsm->ref, gsm_free_muxr); 3257 spin_unlock_irqrestore(&gsm_mux_lock, flags); 3258} 3259 3260static inline unsigned int mux_num_to_base(struct gsm_mux *gsm) 3261{ 3262 return gsm->num * NUM_DLCI; 3263} 3264 3265static inline unsigned int mux_line_to_num(unsigned int line) 3266{ 3267 return line / NUM_DLCI; 3268} 3269 3270/** 3271 * gsm_alloc_mux - allocate a mux 3272 * 3273 * Creates a new mux ready for activation. 3274 */ 3275 3276static struct gsm_mux *gsm_alloc_mux(void) 3277{ 3278 int i; 3279 struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL); 3280 if (gsm == NULL) 3281 return NULL; 3282 gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL); 3283 if (gsm->buf == NULL) { 3284 kfree(gsm); 3285 return NULL; 3286 } 3287 gsm->txframe = kmalloc(2 * (MAX_MTU + PROT_OVERHEAD - 1), GFP_KERNEL); 3288 if (gsm->txframe == NULL) { 3289 kfree(gsm->buf); 3290 kfree(gsm); 3291 return NULL; 3292 } 3293 spin_lock_init(&gsm->lock); 3294 mutex_init(&gsm->mutex); 3295 kref_init(&gsm->ref); 3296 INIT_LIST_HEAD(&gsm->tx_ctrl_list); 3297 INIT_LIST_HEAD(&gsm->tx_data_list); 3298 timer_setup(&gsm->kick_timer, gsm_kick_timer, 0); 3299 timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0); 3300 timer_setup(&gsm->ka_timer, gsm_control_keep_alive, 0); 3301 INIT_WORK(&gsm->tx_work, gsmld_write_task); 3302 init_waitqueue_head(&gsm->event); 3303 spin_lock_init(&gsm->control_lock); 3304 spin_lock_init(&gsm->tx_lock); 3305 3306 gsm->t1 = T1; 3307 gsm->t2 = T2; 3308 gsm->t3 = T3; 3309 gsm->n2 = N2; 3310 gsm->k = K; 3311 gsm->ftype = UIH; 3312 gsm->adaption = 1; 3313 gsm->encoding = GSM_ADV_OPT; 3314 gsm->mru = 64; /* Default to encoding 1 so these should be 64 */ 3315 gsm->mtu = 64; 3316 gsm->dead = true; /* Avoid early tty opens */ 3317 gsm->wait_config = false; /* Disabled */ 3318 gsm->keep_alive = 0; /* Disabled */ 3319 3320 /* Store the instance to the mux array or abort if no space is 3321 * available. 3322 */ 3323 spin_lock(&gsm_mux_lock); 3324 for (i = 0; i < MAX_MUX; i++) { 3325 if (!gsm_mux[i]) { 3326 gsm_mux[i] = gsm; 3327 gsm->num = i; 3328 break; 3329 } 3330 } 3331 spin_unlock(&gsm_mux_lock); 3332 if (i == MAX_MUX) { 3333 mutex_destroy(&gsm->mutex); 3334 kfree(gsm->txframe); 3335 kfree(gsm->buf); 3336 kfree(gsm); 3337 return NULL; 3338 } 3339 3340 return gsm; 3341} 3342 3343static void gsm_copy_config_values(struct gsm_mux *gsm, 3344 struct gsm_config *c) 3345{ 3346 memset(c, 0, sizeof(*c)); 3347 c->adaption = gsm->adaption; 3348 c->encapsulation = gsm->encoding; 3349 c->initiator = gsm->initiator; 3350 c->t1 = gsm->t1; 3351 c->t2 = gsm->t2; 3352 c->t3 = gsm->t3; 3353 c->n2 = gsm->n2; 3354 if (gsm->ftype == UIH) 3355 c->i = 1; 3356 else 3357 c->i = 2; 3358 pr_debug("Ftype %d i %d\n", gsm->ftype, c->i); 3359 c->mru = gsm->mru; 3360 c->mtu = gsm->mtu; 3361 c->k = gsm->k; 3362} 3363 3364static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c) 3365{ 3366 int need_close = 0; 3367 int need_restart = 0; 3368 3369 /* Stuff we don't support yet - UI or I frame transport */ 3370 if (c->adaption != 1 && c->adaption != 2) 3371 return -EOPNOTSUPP; 3372 /* Check the MRU/MTU range looks sane */ 3373 if (c->mru < MIN_MTU || c->mtu < MIN_MTU) 3374 return -EINVAL; 3375 if (c->mru > MAX_MRU || c->mtu > MAX_MTU) 3376 return -EINVAL; 3377 if (c->t3 > MAX_T3) 3378 return -EINVAL; 3379 if (c->n2 > 255) 3380 return -EINVAL; 3381 if (c->encapsulation > 1) /* Basic, advanced, no I */ 3382 return -EINVAL; 3383 if (c->initiator > 1) 3384 return -EINVAL; 3385 if (c->k > MAX_WINDOW_SIZE) 3386 return -EINVAL; 3387 if (c->i == 0 || c->i > 2) /* UIH and UI only */ 3388 return -EINVAL; 3389 /* 3390 * See what is needed for reconfiguration 3391 */ 3392 3393 /* Timing fields */ 3394 if (c->t1 != 0 && c->t1 != gsm->t1) 3395 need_restart = 1; 3396 if (c->t2 != 0 && c->t2 != gsm->t2) 3397 need_restart = 1; 3398 if (c->encapsulation != gsm->encoding) 3399 need_restart = 1; 3400 if (c->adaption != gsm->adaption) 3401 need_restart = 1; 3402 /* Requires care */ 3403 if (c->initiator != gsm->initiator) 3404 need_close = 1; 3405 if (c->mru != gsm->mru) 3406 need_restart = 1; 3407 if (c->mtu != gsm->mtu) 3408 need_restart = 1; 3409 3410 /* 3411 * Close down what is needed, restart and initiate the new 3412 * configuration. On the first time there is no DLCI[0] 3413 * and closing or cleaning up is not necessary. 3414 */ 3415 if (need_close || need_restart) 3416 gsm_cleanup_mux(gsm, true); 3417 3418 gsm->initiator = c->initiator; 3419 gsm->mru = c->mru; 3420 gsm->mtu = c->mtu; 3421 gsm->encoding = c->encapsulation ? GSM_ADV_OPT : GSM_BASIC_OPT; 3422 gsm->adaption = c->adaption; 3423 gsm->n2 = c->n2; 3424 3425 if (c->i == 1) 3426 gsm->ftype = UIH; 3427 else if (c->i == 2) 3428 gsm->ftype = UI; 3429 3430 if (c->t1) 3431 gsm->t1 = c->t1; 3432 if (c->t2) 3433 gsm->t2 = c->t2; 3434 if (c->t3) 3435 gsm->t3 = c->t3; 3436 if (c->k) 3437 gsm->k = c->k; 3438 3439 /* 3440 * FIXME: We need to separate activation/deactivation from adding 3441 * and removing from the mux array 3442 */ 3443 if (gsm->dead) { 3444 int ret = gsm_activate_mux(gsm); 3445 if (ret) 3446 return ret; 3447 if (gsm->initiator) 3448 gsm_dlci_begin_open(gsm->dlci[0]); 3449 } 3450 return 0; 3451} 3452 3453static void gsm_copy_config_ext_values(struct gsm_mux *gsm, 3454 struct gsm_config_ext *ce) 3455{ 3456 memset(ce, 0, sizeof(*ce)); 3457 ce->wait_config = gsm->wait_config ? 1 : 0; 3458 ce->keep_alive = gsm->keep_alive; 3459} 3460 3461static int gsm_config_ext(struct gsm_mux *gsm, struct gsm_config_ext *ce) 3462{ 3463 bool need_restart = false; 3464 unsigned int i; 3465 3466 /* 3467 * Check that userspace doesn't put stuff in here to prevent breakages 3468 * in the future. 3469 */ 3470 for (i = 0; i < ARRAY_SIZE(ce->reserved); i++) 3471 if (ce->reserved[i]) 3472 return -EINVAL; 3473 if (ce->flags & ~GSM_FL_RESTART) 3474 return -EINVAL; 3475 3476 /* Requires care */ 3477 if (ce->flags & GSM_FL_RESTART) 3478 need_restart = true; 3479 3480 /* 3481 * Close down what is needed, restart and initiate the new 3482 * configuration. On the first time there is no DLCI[0] 3483 * and closing or cleaning up is not necessary. 3484 */ 3485 if (need_restart) 3486 gsm_cleanup_mux(gsm, true); 3487 3488 /* 3489 * Setup the new configuration values 3490 */ 3491 gsm->wait_config = ce->wait_config ? true : false; 3492 gsm->keep_alive = ce->keep_alive; 3493 3494 if (gsm->dead) { 3495 int ret = gsm_activate_mux(gsm); 3496 if (ret) 3497 return ret; 3498 if (gsm->initiator) 3499 gsm_dlci_begin_open(gsm->dlci[0]); 3500 } 3501 3502 return 0; 3503} 3504 3505/** 3506 * gsmld_output - write to link 3507 * @gsm: our mux 3508 * @data: bytes to output 3509 * @len: size 3510 * 3511 * Write a block of data from the GSM mux to the data channel. This 3512 * will eventually be serialized from above but at the moment isn't. 3513 */ 3514 3515static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len) 3516{ 3517 if (tty_write_room(gsm->tty) < len) { 3518 set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags); 3519 return -ENOSPC; 3520 } 3521 if (debug & DBG_DATA) 3522 gsm_hex_dump_bytes(__func__, data, len); 3523 return gsm->tty->ops->write(gsm->tty, data, len); 3524} 3525 3526 3527/** 3528 * gsmld_write_trigger - schedule ldisc write task 3529 * @gsm: our mux 3530 */ 3531static void gsmld_write_trigger(struct gsm_mux *gsm) 3532{ 3533 if (!gsm || !gsm->dlci[0] || gsm->dlci[0]->dead) 3534 return; 3535 schedule_work(&gsm->tx_work); 3536} 3537 3538 3539/** 3540 * gsmld_write_task - ldisc write task 3541 * @work: our tx write work 3542 * 3543 * Writes out data to the ldisc if possible. We are doing this here to 3544 * avoid dead-locking. This returns if no space or data is left for output. 3545 */ 3546static void gsmld_write_task(struct work_struct *work) 3547{ 3548 struct gsm_mux *gsm = container_of(work, struct gsm_mux, tx_work); 3549 unsigned long flags; 3550 int i, ret; 3551 3552 /* All outstanding control channel and control messages and one data 3553 * frame is sent. 3554 */ 3555 ret = -ENODEV; 3556 spin_lock_irqsave(&gsm->tx_lock, flags); 3557 if (gsm->tty) 3558 ret = gsm_data_kick(gsm); 3559 spin_unlock_irqrestore(&gsm->tx_lock, flags); 3560 3561 if (ret >= 0) 3562 for (i = 0; i < NUM_DLCI; i++) 3563 if (gsm->dlci[i]) 3564 tty_port_tty_wakeup(&gsm->dlci[i]->port); 3565} 3566 3567/** 3568 * gsmld_attach_gsm - mode set up 3569 * @tty: our tty structure 3570 * @gsm: our mux 3571 * 3572 * Set up the MUX for basic mode and commence connecting to the 3573 * modem. Currently called from the line discipline set up but 3574 * will need moving to an ioctl path. 3575 */ 3576 3577static void gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 3578{ 3579 gsm->tty = tty_kref_get(tty); 3580 /* Turn off tty XON/XOFF handling to handle it explicitly. */ 3581 gsm->old_c_iflag = tty->termios.c_iflag; 3582 tty->termios.c_iflag &= (IXON | IXOFF); 3583} 3584 3585/** 3586 * gsmld_detach_gsm - stop doing 0710 mux 3587 * @tty: tty attached to the mux 3588 * @gsm: mux 3589 * 3590 * Shutdown and then clean up the resources used by the line discipline 3591 */ 3592 3593static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) 3594{ 3595 WARN_ON(tty != gsm->tty); 3596 /* Restore tty XON/XOFF handling. */ 3597 gsm->tty->termios.c_iflag = gsm->old_c_iflag; 3598 tty_kref_put(gsm->tty); 3599 gsm->tty = NULL; 3600} 3601 3602static void gsmld_receive_buf(struct tty_struct *tty, const u8 *cp, 3603 const u8 *fp, size_t count) 3604{ 3605 struct gsm_mux *gsm = tty->disc_data; 3606 u8 flags = TTY_NORMAL; 3607 3608 if (debug & DBG_DATA) 3609 gsm_hex_dump_bytes(__func__, cp, count); 3610 3611 for (; count; count--, cp++) { 3612 if (fp) 3613 flags = *fp++; 3614 switch (flags) { 3615 case TTY_NORMAL: 3616 if (gsm->receive) 3617 gsm->receive(gsm, *cp); 3618 break; 3619 case TTY_OVERRUN: 3620 case TTY_BREAK: 3621 case TTY_PARITY: 3622 case TTY_FRAME: 3623 gsm_error(gsm); 3624 break; 3625 default: 3626 WARN_ONCE(1, "%s: unknown flag %d\n", 3627 tty_name(tty), flags); 3628 break; 3629 } 3630 } 3631 /* FASYNC if needed ? */ 3632 /* If clogged call tty_throttle(tty); */ 3633} 3634 3635/** 3636 * gsmld_flush_buffer - clean input queue 3637 * @tty: terminal device 3638 * 3639 * Flush the input buffer. Called when the line discipline is 3640 * being closed, when the tty layer wants the buffer flushed (eg 3641 * at hangup). 3642 */ 3643 3644static void gsmld_flush_buffer(struct tty_struct *tty) 3645{ 3646} 3647 3648/** 3649 * gsmld_close - close the ldisc for this tty 3650 * @tty: device 3651 * 3652 * Called from the terminal layer when this line discipline is 3653 * being shut down, either because of a close or becsuse of a 3654 * discipline change. The function will not be called while other 3655 * ldisc methods are in progress. 3656 */ 3657 3658static void gsmld_close(struct tty_struct *tty) 3659{ 3660 struct gsm_mux *gsm = tty->disc_data; 3661 3662 /* The ldisc locks and closes the port before calling our close. This 3663 * means we have no way to do a proper disconnect. We will not bother 3664 * to do one. 3665 */ 3666 gsm_cleanup_mux(gsm, false); 3667 3668 gsmld_detach_gsm(tty, gsm); 3669 3670 gsmld_flush_buffer(tty); 3671 /* Do other clean up here */ 3672 mux_put(gsm); 3673} 3674 3675/** 3676 * gsmld_open - open an ldisc 3677 * @tty: terminal to open 3678 * 3679 * Called when this line discipline is being attached to the 3680 * terminal device. Can sleep. Called serialized so that no 3681 * other events will occur in parallel. No further open will occur 3682 * until a close. 3683 */ 3684 3685static int gsmld_open(struct tty_struct *tty) 3686{ 3687 struct gsm_mux *gsm; 3688 3689 if (!capable(CAP_NET_ADMIN)) 3690 return -EPERM; 3691 3692 if (tty->ops->write == NULL) 3693 return -EINVAL; 3694 3695 /* Attach our ldisc data */ 3696 gsm = gsm_alloc_mux(); 3697 if (gsm == NULL) 3698 return -ENOMEM; 3699 3700 tty->disc_data = gsm; 3701 tty->receive_room = 65536; 3702 3703 /* Attach the initial passive connection */ 3704 gsmld_attach_gsm(tty, gsm); 3705 3706 /* The mux will not be activated yet, we wait for correct 3707 * configuration first. 3708 */ 3709 if (gsm->encoding == GSM_BASIC_OPT) 3710 gsm->receive = gsm0_receive; 3711 else 3712 gsm->receive = gsm1_receive; 3713 3714 return 0; 3715} 3716 3717/** 3718 * gsmld_write_wakeup - asynchronous I/O notifier 3719 * @tty: tty device 3720 * 3721 * Required for the ptys, serial driver etc. since processes 3722 * that attach themselves to the master and rely on ASYNC 3723 * IO must be woken up 3724 */ 3725 3726static void gsmld_write_wakeup(struct tty_struct *tty) 3727{ 3728 struct gsm_mux *gsm = tty->disc_data; 3729 3730 /* Queue poll */ 3731 gsmld_write_trigger(gsm); 3732} 3733 3734/** 3735 * gsmld_read - read function for tty 3736 * @tty: tty device 3737 * @file: file object 3738 * @buf: userspace buffer pointer 3739 * @nr: size of I/O 3740 * @cookie: unused 3741 * @offset: unused 3742 * 3743 * Perform reads for the line discipline. We are guaranteed that the 3744 * line discipline will not be closed under us but we may get multiple 3745 * parallel readers and must handle this ourselves. We may also get 3746 * a hangup. Always called in user context, may sleep. 3747 * 3748 * This code must be sure never to sleep through a hangup. 3749 */ 3750 3751static ssize_t gsmld_read(struct tty_struct *tty, struct file *file, u8 *buf, 3752 size_t nr, void **cookie, unsigned long offset) 3753{ 3754 return -EOPNOTSUPP; 3755} 3756 3757/** 3758 * gsmld_write - write function for tty 3759 * @tty: tty device 3760 * @file: file object 3761 * @buf: userspace buffer pointer 3762 * @nr: size of I/O 3763 * 3764 * Called when the owner of the device wants to send a frame 3765 * itself (or some other control data). The data is transferred 3766 * as-is and must be properly framed and checksummed as appropriate 3767 * by userspace. Frames are either sent whole or not at all as this 3768 * avoids pain user side. 3769 */ 3770 3771static ssize_t gsmld_write(struct tty_struct *tty, struct file *file, 3772 const u8 *buf, size_t nr) 3773{ 3774 struct gsm_mux *gsm = tty->disc_data; 3775 unsigned long flags; 3776 size_t space; 3777 int ret; 3778 3779 if (!gsm) 3780 return -ENODEV; 3781 3782 ret = -ENOBUFS; 3783 spin_lock_irqsave(&gsm->tx_lock, flags); 3784 space = tty_write_room(tty); 3785 if (space >= nr) 3786 ret = tty->ops->write(tty, buf, nr); 3787 else 3788 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 3789 spin_unlock_irqrestore(&gsm->tx_lock, flags); 3790 3791 return ret; 3792} 3793 3794/** 3795 * gsmld_poll - poll method for N_GSM0710 3796 * @tty: terminal device 3797 * @file: file accessing it 3798 * @wait: poll table 3799 * 3800 * Called when the line discipline is asked to poll() for data or 3801 * for special events. This code is not serialized with respect to 3802 * other events save open/close. 3803 * 3804 * This code must be sure never to sleep through a hangup. 3805 * Called without the kernel lock held - fine 3806 */ 3807 3808static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file, 3809 poll_table *wait) 3810{ 3811 __poll_t mask = 0; 3812 struct gsm_mux *gsm = tty->disc_data; 3813 3814 poll_wait(file, &tty->read_wait, wait); 3815 poll_wait(file, &tty->write_wait, wait); 3816 3817 if (gsm->dead) 3818 mask |= EPOLLHUP; 3819 if (tty_hung_up_p(file)) 3820 mask |= EPOLLHUP; 3821 if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) 3822 mask |= EPOLLHUP; 3823 if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0) 3824 mask |= EPOLLOUT | EPOLLWRNORM; 3825 return mask; 3826} 3827 3828static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd, 3829 unsigned long arg) 3830{ 3831 struct gsm_config c; 3832 struct gsm_config_ext ce; 3833 struct gsm_dlci_config dc; 3834 struct gsm_mux *gsm = tty->disc_data; 3835 unsigned int base, addr; 3836 struct gsm_dlci *dlci; 3837 3838 switch (cmd) { 3839 case GSMIOC_GETCONF: 3840 gsm_copy_config_values(gsm, &c); 3841 if (copy_to_user((void __user *)arg, &c, sizeof(c))) 3842 return -EFAULT; 3843 return 0; 3844 case GSMIOC_SETCONF: 3845 if (copy_from_user(&c, (void __user *)arg, sizeof(c))) 3846 return -EFAULT; 3847 return gsm_config(gsm, &c); 3848 case GSMIOC_GETFIRST: 3849 base = mux_num_to_base(gsm); 3850 return put_user(base + 1, (__u32 __user *)arg); 3851 case GSMIOC_GETCONF_EXT: 3852 gsm_copy_config_ext_values(gsm, &ce); 3853 if (copy_to_user((void __user *)arg, &ce, sizeof(ce))) 3854 return -EFAULT; 3855 return 0; 3856 case GSMIOC_SETCONF_EXT: 3857 if (copy_from_user(&ce, (void __user *)arg, sizeof(ce))) 3858 return -EFAULT; 3859 return gsm_config_ext(gsm, &ce); 3860 case GSMIOC_GETCONF_DLCI: 3861 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc))) 3862 return -EFAULT; 3863 if (dc.channel == 0 || dc.channel >= NUM_DLCI) 3864 return -EINVAL; 3865 addr = array_index_nospec(dc.channel, NUM_DLCI); 3866 dlci = gsm->dlci[addr]; 3867 if (!dlci) { 3868 dlci = gsm_dlci_alloc(gsm, addr); 3869 if (!dlci) 3870 return -ENOMEM; 3871 } 3872 gsm_dlci_copy_config_values(dlci, &dc); 3873 if (copy_to_user((void __user *)arg, &dc, sizeof(dc))) 3874 return -EFAULT; 3875 return 0; 3876 case GSMIOC_SETCONF_DLCI: 3877 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc))) 3878 return -EFAULT; 3879 if (dc.channel == 0 || dc.channel >= NUM_DLCI) 3880 return -EINVAL; 3881 addr = array_index_nospec(dc.channel, NUM_DLCI); 3882 dlci = gsm->dlci[addr]; 3883 if (!dlci) { 3884 dlci = gsm_dlci_alloc(gsm, addr); 3885 if (!dlci) 3886 return -ENOMEM; 3887 } 3888 return gsm_dlci_config(dlci, &dc, 0); 3889 default: 3890 return n_tty_ioctl_helper(tty, cmd, arg); 3891 } 3892} 3893 3894/* 3895 * Network interface 3896 * 3897 */ 3898 3899static int gsm_mux_net_open(struct net_device *net) 3900{ 3901 pr_debug("%s called\n", __func__); 3902 netif_start_queue(net); 3903 return 0; 3904} 3905 3906static int gsm_mux_net_close(struct net_device *net) 3907{ 3908 netif_stop_queue(net); 3909 return 0; 3910} 3911 3912static void dlci_net_free(struct gsm_dlci *dlci) 3913{ 3914 if (!dlci->net) { 3915 WARN_ON(1); 3916 return; 3917 } 3918 dlci->adaption = dlci->prev_adaption; 3919 dlci->data = dlci->prev_data; 3920 free_netdev(dlci->net); 3921 dlci->net = NULL; 3922} 3923static void net_free(struct kref *ref) 3924{ 3925 struct gsm_mux_net *mux_net; 3926 struct gsm_dlci *dlci; 3927 3928 mux_net = container_of(ref, struct gsm_mux_net, ref); 3929 dlci = mux_net->dlci; 3930 3931 if (dlci->net) { 3932 unregister_netdev(dlci->net); 3933 dlci_net_free(dlci); 3934 } 3935} 3936 3937static inline void muxnet_get(struct gsm_mux_net *mux_net) 3938{ 3939 kref_get(&mux_net->ref); 3940} 3941 3942static inline void muxnet_put(struct gsm_mux_net *mux_net) 3943{ 3944 kref_put(&mux_net->ref, net_free); 3945} 3946 3947static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb, 3948 struct net_device *net) 3949{ 3950 struct gsm_mux_net *mux_net = netdev_priv(net); 3951 struct gsm_dlci *dlci = mux_net->dlci; 3952 muxnet_get(mux_net); 3953 3954 skb_queue_head(&dlci->skb_list, skb); 3955 net->stats.tx_packets++; 3956 net->stats.tx_bytes += skb->len; 3957 gsm_dlci_data_kick(dlci); 3958 /* And tell the kernel when the last transmit started. */ 3959 netif_trans_update(net); 3960 muxnet_put(mux_net); 3961 return NETDEV_TX_OK; 3962} 3963 3964/* called when a packet did not ack after watchdogtimeout */ 3965static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue) 3966{ 3967 /* Tell syslog we are hosed. */ 3968 dev_dbg(&net->dev, "Tx timed out.\n"); 3969 3970 /* Update statistics */ 3971 net->stats.tx_errors++; 3972} 3973 3974static void gsm_mux_rx_netchar(struct gsm_dlci *dlci, const u8 *in_buf, int size) 3975{ 3976 struct net_device *net = dlci->net; 3977 struct sk_buff *skb; 3978 struct gsm_mux_net *mux_net = netdev_priv(net); 3979 muxnet_get(mux_net); 3980 3981 /* Allocate an sk_buff */ 3982 skb = dev_alloc_skb(size + NET_IP_ALIGN); 3983 if (!skb) { 3984 /* We got no receive buffer. */ 3985 net->stats.rx_dropped++; 3986 muxnet_put(mux_net); 3987 return; 3988 } 3989 skb_reserve(skb, NET_IP_ALIGN); 3990 skb_put_data(skb, in_buf, size); 3991 3992 skb->dev = net; 3993 skb->protocol = htons(ETH_P_IP); 3994 3995 /* Ship it off to the kernel */ 3996 netif_rx(skb); 3997 3998 /* update out statistics */ 3999 net->stats.rx_packets++; 4000 net->stats.rx_bytes += size; 4001 muxnet_put(mux_net); 4002 return; 4003} 4004 4005static void gsm_mux_net_init(struct net_device *net) 4006{ 4007 static const struct net_device_ops gsm_netdev_ops = { 4008 .ndo_open = gsm_mux_net_open, 4009 .ndo_stop = gsm_mux_net_close, 4010 .ndo_start_xmit = gsm_mux_net_start_xmit, 4011 .ndo_tx_timeout = gsm_mux_net_tx_timeout, 4012 }; 4013 4014 net->netdev_ops = &gsm_netdev_ops; 4015 4016 /* fill in the other fields */ 4017 net->watchdog_timeo = GSM_NET_TX_TIMEOUT; 4018 net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 4019 net->type = ARPHRD_NONE; 4020 net->tx_queue_len = 10; 4021} 4022 4023 4024/* caller holds the dlci mutex */ 4025static void gsm_destroy_network(struct gsm_dlci *dlci) 4026{ 4027 struct gsm_mux_net *mux_net; 4028 4029 pr_debug("destroy network interface\n"); 4030 if (!dlci->net) 4031 return; 4032 mux_net = netdev_priv(dlci->net); 4033 muxnet_put(mux_net); 4034} 4035 4036 4037/* caller holds the dlci mutex */ 4038static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc) 4039{ 4040 char *netname; 4041 int retval = 0; 4042 struct net_device *net; 4043 struct gsm_mux_net *mux_net; 4044 4045 if (!capable(CAP_NET_ADMIN)) 4046 return -EPERM; 4047 4048 /* Already in a non tty mode */ 4049 if (dlci->adaption > 2) 4050 return -EBUSY; 4051 4052 if (nc->protocol != htons(ETH_P_IP)) 4053 return -EPROTONOSUPPORT; 4054 4055 if (nc->adaption != 3 && nc->adaption != 4) 4056 return -EPROTONOSUPPORT; 4057 4058 pr_debug("create network interface\n"); 4059 4060 netname = "gsm%d"; 4061 if (nc->if_name[0] != '\0') 4062 netname = nc->if_name; 4063 net = alloc_netdev(sizeof(struct gsm_mux_net), netname, 4064 NET_NAME_UNKNOWN, gsm_mux_net_init); 4065 if (!net) { 4066 pr_err("alloc_netdev failed\n"); 4067 return -ENOMEM; 4068 } 4069 net->mtu = dlci->mtu; 4070 net->min_mtu = MIN_MTU; 4071 net->max_mtu = dlci->mtu; 4072 mux_net = netdev_priv(net); 4073 mux_net->dlci = dlci; 4074 kref_init(&mux_net->ref); 4075 strscpy(nc->if_name, net->name); /* return net name */ 4076 4077 /* reconfigure dlci for network */ 4078 dlci->prev_adaption = dlci->adaption; 4079 dlci->prev_data = dlci->data; 4080 dlci->adaption = nc->adaption; 4081 dlci->data = gsm_mux_rx_netchar; 4082 dlci->net = net; 4083 4084 pr_debug("register netdev\n"); 4085 retval = register_netdev(net); 4086 if (retval) { 4087 pr_err("network register fail %d\n", retval); 4088 dlci_net_free(dlci); 4089 return retval; 4090 } 4091 return net->ifindex; /* return network index */ 4092} 4093 4094/* Line discipline for real tty */ 4095static struct tty_ldisc_ops tty_ldisc_packet = { 4096 .owner = THIS_MODULE, 4097 .num = N_GSM0710, 4098 .name = "n_gsm", 4099 .open = gsmld_open, 4100 .close = gsmld_close, 4101 .flush_buffer = gsmld_flush_buffer, 4102 .read = gsmld_read, 4103 .write = gsmld_write, 4104 .ioctl = gsmld_ioctl, 4105 .poll = gsmld_poll, 4106 .receive_buf = gsmld_receive_buf, 4107 .write_wakeup = gsmld_write_wakeup 4108}; 4109 4110/* 4111 * Virtual tty side 4112 */ 4113 4114/** 4115 * gsm_modem_upd_via_data - send modem bits via convergence layer 4116 * @dlci: channel 4117 * @brk: break signal 4118 * 4119 * Send an empty frame to signal mobile state changes and to transmit the 4120 * break signal for adaption 2. 4121 */ 4122 4123static void gsm_modem_upd_via_data(struct gsm_dlci *dlci, u8 brk) 4124{ 4125 struct gsm_mux *gsm = dlci->gsm; 4126 unsigned long flags; 4127 4128 if (dlci->state != DLCI_OPEN || dlci->adaption != 2) 4129 return; 4130 4131 spin_lock_irqsave(&gsm->tx_lock, flags); 4132 gsm_dlci_modem_output(gsm, dlci, brk); 4133 spin_unlock_irqrestore(&gsm->tx_lock, flags); 4134} 4135 4136/** 4137 * gsm_modem_upd_via_msc - send modem bits via control frame 4138 * @dlci: channel 4139 * @brk: break signal 4140 */ 4141 4142static int gsm_modem_upd_via_msc(struct gsm_dlci *dlci, u8 brk) 4143{ 4144 u8 modembits[3]; 4145 struct gsm_control *ctrl; 4146 int len = 2; 4147 4148 if (dlci->gsm->encoding != GSM_BASIC_OPT) 4149 return 0; 4150 4151 modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */ 4152 if (!brk) { 4153 modembits[1] = (gsm_encode_modem(dlci) << 1) | EA; 4154 } else { 4155 modembits[1] = gsm_encode_modem(dlci) << 1; 4156 modembits[2] = (brk << 4) | 2 | EA; /* Length, Break, EA */ 4157 len++; 4158 } 4159 ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len); 4160 if (ctrl == NULL) 4161 return -ENOMEM; 4162 return gsm_control_wait(dlci->gsm, ctrl); 4163} 4164 4165/** 4166 * gsm_modem_send_initial_msc - Send initial modem status message 4167 * 4168 * @dlci: channel 4169 * 4170 * Send an initial MSC message after DLCI open to set the initial 4171 * modem status lines. This is only done for basic mode. 4172 * Does not wait for a response as we cannot block the input queue 4173 * processing. 4174 */ 4175static int gsm_modem_send_initial_msc(struct gsm_dlci *dlci) 4176{ 4177 u8 modembits[2]; 4178 4179 if (dlci->adaption != 1 || dlci->gsm->encoding != GSM_BASIC_OPT) 4180 return 0; 4181 4182 modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */ 4183 modembits[1] = (gsm_encode_modem(dlci) << 1) | EA; 4184 return gsm_control_command(dlci->gsm, CMD_MSC, (const u8 *)&modembits, 2); 4185} 4186 4187/** 4188 * gsm_modem_update - send modem status line state 4189 * @dlci: channel 4190 * @brk: break signal 4191 */ 4192 4193static int gsm_modem_update(struct gsm_dlci *dlci, u8 brk) 4194{ 4195 if (dlci->gsm->dead) 4196 return -EL2HLT; 4197 if (dlci->adaption == 2) { 4198 /* Send convergence layer type 2 empty data frame. */ 4199 gsm_modem_upd_via_data(dlci, brk); 4200 return 0; 4201 } else if (dlci->gsm->encoding == GSM_BASIC_OPT) { 4202 /* Send as MSC control message. */ 4203 return gsm_modem_upd_via_msc(dlci, brk); 4204 } 4205 4206 /* Modem status lines are not supported. */ 4207 return -EPROTONOSUPPORT; 4208} 4209 4210/** 4211 * gsm_wait_modem_change - wait for modem status line change 4212 * @dlci: channel 4213 * @mask: modem status line bits 4214 * 4215 * The function returns if: 4216 * - any given modem status line bit changed 4217 * - the wait event function got interrupted (e.g. by a signal) 4218 * - the underlying DLCI was closed 4219 * - the underlying ldisc device was removed 4220 */ 4221static int gsm_wait_modem_change(struct gsm_dlci *dlci, u32 mask) 4222{ 4223 struct gsm_mux *gsm = dlci->gsm; 4224 u32 old = dlci->modem_rx; 4225 int ret; 4226 4227 ret = wait_event_interruptible(gsm->event, gsm->dead || 4228 dlci->state != DLCI_OPEN || 4229 (old ^ dlci->modem_rx) & mask); 4230 if (gsm->dead) 4231 return -ENODEV; 4232 if (dlci->state != DLCI_OPEN) 4233 return -EL2NSYNC; 4234 return ret; 4235} 4236 4237static bool gsm_carrier_raised(struct tty_port *port) 4238{ 4239 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 4240 struct gsm_mux *gsm = dlci->gsm; 4241 4242 /* Not yet open so no carrier info */ 4243 if (dlci->state != DLCI_OPEN) 4244 return false; 4245 if (debug & DBG_CD_ON) 4246 return true; 4247 4248 /* 4249 * Basic mode with control channel in ADM mode may not respond 4250 * to CMD_MSC at all and modem_rx is empty. 4251 */ 4252 if (gsm->encoding == GSM_BASIC_OPT && 4253 gsm->dlci[0]->mode == DLCI_MODE_ADM && !dlci->modem_rx) 4254 return true; 4255 4256 return dlci->modem_rx & TIOCM_CD; 4257} 4258 4259static void gsm_dtr_rts(struct tty_port *port, bool active) 4260{ 4261 struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port); 4262 unsigned int modem_tx = dlci->modem_tx; 4263 if (active) 4264 modem_tx |= TIOCM_DTR | TIOCM_RTS; 4265 else 4266 modem_tx &= ~(TIOCM_DTR | TIOCM_RTS); 4267 if (modem_tx != dlci->modem_tx) { 4268 dlci->modem_tx = modem_tx; 4269 gsm_modem_update(dlci, 0); 4270 } 4271} 4272 4273static const struct tty_port_operations gsm_port_ops = { 4274 .carrier_raised = gsm_carrier_raised, 4275 .dtr_rts = gsm_dtr_rts, 4276 .destruct = gsm_dlci_free, 4277}; 4278 4279static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty) 4280{ 4281 struct gsm_mux *gsm; 4282 struct gsm_dlci *dlci, *dlci0; 4283 unsigned int line = tty->index; 4284 unsigned int mux = mux_line_to_num(line); 4285 bool alloc = false; 4286 int ret; 4287 4288 line = line & 0x3F; 4289 4290 if (mux >= MAX_MUX) 4291 return -ENXIO; 4292 /* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */ 4293 if (gsm_mux[mux] == NULL) 4294 return -EUNATCH; 4295 if (line == 0 || line > 61) /* 62/63 reserved */ 4296 return -ECHRNG; 4297 gsm = gsm_mux[mux]; 4298 if (gsm->dead) 4299 return -EL2HLT; 4300 /* If DLCI 0 is not yet fully open return an error. 4301 This is ok from a locking 4302 perspective as we don't have to worry about this 4303 if DLCI0 is lost */ 4304 mutex_lock(&gsm->mutex); 4305 4306 dlci0 = gsm->dlci[0]; 4307 if (dlci0 && dlci0->state != DLCI_OPEN) { 4308 mutex_unlock(&gsm->mutex); 4309 4310 if (dlci0->state == DLCI_OPENING) 4311 wait_event(gsm->event, dlci0->state != DLCI_OPENING); 4312 4313 if (dlci0->state != DLCI_OPEN) 4314 return -EL2NSYNC; 4315 4316 mutex_lock(&gsm->mutex); 4317 } 4318 4319 dlci = gsm->dlci[line]; 4320 if (dlci == NULL) { 4321 alloc = true; 4322 dlci = gsm_dlci_alloc(gsm, line); 4323 } 4324 if (dlci == NULL) { 4325 mutex_unlock(&gsm->mutex); 4326 return -ENOMEM; 4327 } 4328 ret = tty_port_install(&dlci->port, driver, tty); 4329 if (ret) { 4330 if (alloc) 4331 dlci_put(dlci); 4332 mutex_unlock(&gsm->mutex); 4333 return ret; 4334 } 4335 4336 dlci_get(dlci); 4337 dlci_get(gsm->dlci[0]); 4338 mux_get(gsm); 4339 tty->driver_data = dlci; 4340 mutex_unlock(&gsm->mutex); 4341 4342 return 0; 4343} 4344 4345static int gsmtty_open(struct tty_struct *tty, struct file *filp) 4346{ 4347 struct gsm_dlci *dlci = tty->driver_data; 4348 struct tty_port *port = &dlci->port; 4349 4350 port->count++; 4351 tty_port_tty_set(port, tty); 4352 4353 dlci->modem_rx = 0; 4354 /* We could in theory open and close before we wait - eg if we get 4355 a DM straight back. This is ok as that will have caused a hangup */ 4356 tty_port_set_initialized(port, true); 4357 /* Start sending off SABM messages */ 4358 if (!dlci->gsm->wait_config) { 4359 /* Start sending off SABM messages */ 4360 if (dlci->gsm->initiator) 4361 gsm_dlci_begin_open(dlci); 4362 else 4363 gsm_dlci_set_opening(dlci); 4364 } else { 4365 gsm_dlci_set_wait_config(dlci); 4366 } 4367 /* And wait for virtual carrier */ 4368 return tty_port_block_til_ready(port, tty, filp); 4369} 4370 4371static void gsmtty_close(struct tty_struct *tty, struct file *filp) 4372{ 4373 struct gsm_dlci *dlci = tty->driver_data; 4374 4375 if (dlci == NULL) 4376 return; 4377 if (dlci->state == DLCI_CLOSED) 4378 return; 4379 mutex_lock(&dlci->mutex); 4380 gsm_destroy_network(dlci); 4381 mutex_unlock(&dlci->mutex); 4382 if (tty_port_close_start(&dlci->port, tty, filp) == 0) 4383 return; 4384 gsm_dlci_begin_close(dlci); 4385 if (tty_port_initialized(&dlci->port) && C_HUPCL(tty)) 4386 tty_port_lower_dtr_rts(&dlci->port); 4387 tty_port_close_end(&dlci->port, tty); 4388 tty_port_tty_set(&dlci->port, NULL); 4389 return; 4390} 4391 4392static void gsmtty_hangup(struct tty_struct *tty) 4393{ 4394 struct gsm_dlci *dlci = tty->driver_data; 4395 if (dlci->state == DLCI_CLOSED) 4396 return; 4397 tty_port_hangup(&dlci->port); 4398 gsm_dlci_begin_close(dlci); 4399} 4400 4401static ssize_t gsmtty_write(struct tty_struct *tty, const u8 *buf, size_t len) 4402{ 4403 int sent; 4404 struct gsm_dlci *dlci = tty->driver_data; 4405 if (dlci->state == DLCI_CLOSED) 4406 return -EINVAL; 4407 /* Stuff the bytes into the fifo queue */ 4408 sent = kfifo_in_locked(&dlci->fifo, buf, len, &dlci->lock); 4409 /* Need to kick the channel */ 4410 gsm_dlci_data_kick(dlci); 4411 return sent; 4412} 4413 4414static unsigned int gsmtty_write_room(struct tty_struct *tty) 4415{ 4416 struct gsm_dlci *dlci = tty->driver_data; 4417 if (dlci->state == DLCI_CLOSED) 4418 return 0; 4419 return kfifo_avail(&dlci->fifo); 4420} 4421 4422static unsigned int gsmtty_chars_in_buffer(struct tty_struct *tty) 4423{ 4424 struct gsm_dlci *dlci = tty->driver_data; 4425 if (dlci->state == DLCI_CLOSED) 4426 return 0; 4427 return kfifo_len(&dlci->fifo); 4428} 4429 4430static void gsmtty_flush_buffer(struct tty_struct *tty) 4431{ 4432 struct gsm_dlci *dlci = tty->driver_data; 4433 unsigned long flags; 4434 4435 if (dlci->state == DLCI_CLOSED) 4436 return; 4437 /* Caution needed: If we implement reliable transport classes 4438 then the data being transmitted can't simply be junked once 4439 it has first hit the stack. Until then we can just blow it 4440 away */ 4441 spin_lock_irqsave(&dlci->lock, flags); 4442 kfifo_reset(&dlci->fifo); 4443 spin_unlock_irqrestore(&dlci->lock, flags); 4444 /* Need to unhook this DLCI from the transmit queue logic */ 4445} 4446 4447static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout) 4448{ 4449 /* The FIFO handles the queue so the kernel will do the right 4450 thing waiting on chars_in_buffer before calling us. No work 4451 to do here */ 4452} 4453 4454static int gsmtty_tiocmget(struct tty_struct *tty) 4455{ 4456 struct gsm_dlci *dlci = tty->driver_data; 4457 if (dlci->state == DLCI_CLOSED) 4458 return -EINVAL; 4459 return dlci->modem_rx; 4460} 4461 4462static int gsmtty_tiocmset(struct tty_struct *tty, 4463 unsigned int set, unsigned int clear) 4464{ 4465 struct gsm_dlci *dlci = tty->driver_data; 4466 unsigned int modem_tx = dlci->modem_tx; 4467 4468 if (dlci->state == DLCI_CLOSED) 4469 return -EINVAL; 4470 modem_tx &= ~clear; 4471 modem_tx |= set; 4472 4473 if (modem_tx != dlci->modem_tx) { 4474 dlci->modem_tx = modem_tx; 4475 return gsm_modem_update(dlci, 0); 4476 } 4477 return 0; 4478} 4479 4480 4481static int gsmtty_ioctl(struct tty_struct *tty, 4482 unsigned int cmd, unsigned long arg) 4483{ 4484 struct gsm_dlci *dlci = tty->driver_data; 4485 struct gsm_netconfig nc; 4486 struct gsm_dlci_config dc; 4487 int index; 4488 4489 if (dlci->state == DLCI_CLOSED) 4490 return -EINVAL; 4491 switch (cmd) { 4492 case GSMIOC_ENABLE_NET: 4493 if (copy_from_user(&nc, (void __user *)arg, sizeof(nc))) 4494 return -EFAULT; 4495 nc.if_name[IFNAMSIZ-1] = '\0'; 4496 /* return net interface index or error code */ 4497 mutex_lock(&dlci->mutex); 4498 index = gsm_create_network(dlci, &nc); 4499 mutex_unlock(&dlci->mutex); 4500 if (copy_to_user((void __user *)arg, &nc, sizeof(nc))) 4501 return -EFAULT; 4502 return index; 4503 case GSMIOC_DISABLE_NET: 4504 if (!capable(CAP_NET_ADMIN)) 4505 return -EPERM; 4506 mutex_lock(&dlci->mutex); 4507 gsm_destroy_network(dlci); 4508 mutex_unlock(&dlci->mutex); 4509 return 0; 4510 case GSMIOC_GETCONF_DLCI: 4511 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc))) 4512 return -EFAULT; 4513 if (dc.channel != dlci->addr) 4514 return -EPERM; 4515 gsm_dlci_copy_config_values(dlci, &dc); 4516 if (copy_to_user((void __user *)arg, &dc, sizeof(dc))) 4517 return -EFAULT; 4518 return 0; 4519 case GSMIOC_SETCONF_DLCI: 4520 if (copy_from_user(&dc, (void __user *)arg, sizeof(dc))) 4521 return -EFAULT; 4522 if (dc.channel >= NUM_DLCI) 4523 return -EINVAL; 4524 if (dc.channel != 0 && dc.channel != dlci->addr) 4525 return -EPERM; 4526 return gsm_dlci_config(dlci, &dc, 1); 4527 case TIOCMIWAIT: 4528 return gsm_wait_modem_change(dlci, (u32)arg); 4529 default: 4530 return -ENOIOCTLCMD; 4531 } 4532} 4533 4534static void gsmtty_set_termios(struct tty_struct *tty, 4535 const struct ktermios *old) 4536{ 4537 struct gsm_dlci *dlci = tty->driver_data; 4538 if (dlci->state == DLCI_CLOSED) 4539 return; 4540 /* For the moment its fixed. In actual fact the speed information 4541 for the virtual channel can be propogated in both directions by 4542 the RPN control message. This however rapidly gets nasty as we 4543 then have to remap modem signals each way according to whether 4544 our virtual cable is null modem etc .. */ 4545 tty_termios_copy_hw(&tty->termios, old); 4546} 4547 4548static void gsmtty_throttle(struct tty_struct *tty) 4549{ 4550 struct gsm_dlci *dlci = tty->driver_data; 4551 if (dlci->state == DLCI_CLOSED) 4552 return; 4553 if (C_CRTSCTS(tty)) 4554 dlci->modem_tx &= ~TIOCM_RTS; 4555 dlci->throttled = true; 4556 /* Send an MSC with RTS cleared */ 4557 gsm_modem_update(dlci, 0); 4558} 4559 4560static void gsmtty_unthrottle(struct tty_struct *tty) 4561{ 4562 struct gsm_dlci *dlci = tty->driver_data; 4563 if (dlci->state == DLCI_CLOSED) 4564 return; 4565 if (C_CRTSCTS(tty)) 4566 dlci->modem_tx |= TIOCM_RTS; 4567 dlci->throttled = false; 4568 /* Send an MSC with RTS set */ 4569 gsm_modem_update(dlci, 0); 4570} 4571 4572static int gsmtty_break_ctl(struct tty_struct *tty, int state) 4573{ 4574 struct gsm_dlci *dlci = tty->driver_data; 4575 int encode = 0; /* Off */ 4576 if (dlci->state == DLCI_CLOSED) 4577 return -EINVAL; 4578 4579 if (state == -1) /* "On indefinitely" - we can't encode this 4580 properly */ 4581 encode = 0x0F; 4582 else if (state > 0) { 4583 encode = state / 200; /* mS to encoding */ 4584 if (encode > 0x0F) 4585 encode = 0x0F; /* Best effort */ 4586 } 4587 return gsm_modem_update(dlci, encode); 4588} 4589 4590static void gsmtty_cleanup(struct tty_struct *tty) 4591{ 4592 struct gsm_dlci *dlci = tty->driver_data; 4593 struct gsm_mux *gsm = dlci->gsm; 4594 4595 dlci_put(dlci); 4596 dlci_put(gsm->dlci[0]); 4597 mux_put(gsm); 4598} 4599 4600/* Virtual ttys for the demux */ 4601static const struct tty_operations gsmtty_ops = { 4602 .install = gsmtty_install, 4603 .open = gsmtty_open, 4604 .close = gsmtty_close, 4605 .write = gsmtty_write, 4606 .write_room = gsmtty_write_room, 4607 .chars_in_buffer = gsmtty_chars_in_buffer, 4608 .flush_buffer = gsmtty_flush_buffer, 4609 .ioctl = gsmtty_ioctl, 4610 .throttle = gsmtty_throttle, 4611 .unthrottle = gsmtty_unthrottle, 4612 .set_termios = gsmtty_set_termios, 4613 .hangup = gsmtty_hangup, 4614 .wait_until_sent = gsmtty_wait_until_sent, 4615 .tiocmget = gsmtty_tiocmget, 4616 .tiocmset = gsmtty_tiocmset, 4617 .break_ctl = gsmtty_break_ctl, 4618 .cleanup = gsmtty_cleanup, 4619}; 4620 4621 4622 4623static int __init gsm_init(void) 4624{ 4625 /* Fill in our line protocol discipline, and register it */ 4626 int status = tty_register_ldisc(&tty_ldisc_packet); 4627 if (status != 0) { 4628 pr_err("n_gsm: can't register line discipline (err = %d)\n", 4629 status); 4630 return status; 4631 } 4632 4633 gsm_tty_driver = tty_alloc_driver(GSM_TTY_MINORS, TTY_DRIVER_REAL_RAW | 4634 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_HARDWARE_BREAK); 4635 if (IS_ERR(gsm_tty_driver)) { 4636 pr_err("gsm_init: tty allocation failed.\n"); 4637 status = PTR_ERR(gsm_tty_driver); 4638 goto err_unreg_ldisc; 4639 } 4640 gsm_tty_driver->driver_name = "gsmtty"; 4641 gsm_tty_driver->name = "gsmtty"; 4642 gsm_tty_driver->major = 0; /* Dynamic */ 4643 gsm_tty_driver->minor_start = 0; 4644 gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; 4645 gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL; 4646 gsm_tty_driver->init_termios = tty_std_termios; 4647 /* Fixme */ 4648 gsm_tty_driver->init_termios.c_lflag &= ~ECHO; 4649 tty_set_operations(gsm_tty_driver, &gsmtty_ops); 4650 4651 if (tty_register_driver(gsm_tty_driver)) { 4652 pr_err("gsm_init: tty registration failed.\n"); 4653 status = -EBUSY; 4654 goto err_put_driver; 4655 } 4656 pr_debug("gsm_init: loaded as %d,%d.\n", 4657 gsm_tty_driver->major, gsm_tty_driver->minor_start); 4658 return 0; 4659err_put_driver: 4660 tty_driver_kref_put(gsm_tty_driver); 4661err_unreg_ldisc: 4662 tty_unregister_ldisc(&tty_ldisc_packet); 4663 return status; 4664} 4665 4666static void __exit gsm_exit(void) 4667{ 4668 tty_unregister_ldisc(&tty_ldisc_packet); 4669 tty_unregister_driver(gsm_tty_driver); 4670 tty_driver_kref_put(gsm_tty_driver); 4671} 4672 4673module_init(gsm_init); 4674module_exit(gsm_exit); 4675 4676 4677MODULE_DESCRIPTION("GSM 0710 tty multiplexor"); 4678MODULE_LICENSE("GPL"); 4679MODULE_ALIAS_LDISC(N_GSM0710);
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