1 /* 2 * net/dccp/options.c 3 * 4 * An implementation of the DCCP protocol 5 * Copyright (c) 2005 Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org> 6 * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net> 7 * Copyright (c) 2005 Ian McDonald <iam4@cs.waikato.ac.nz> 8 * 9 * This program is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU General Public License 11 * as published by the Free Software Foundation; either version 12 * 2 of the License, or (at your option) any later version. 13 */ 14 #include <linux/dccp.h> 15 #include <linux/module.h> 16 #include <linux/types.h> 17 #include <linux/kernel.h> 18 #include <linux/skbuff.h> 19 20 #include "ackvec.h" 21 #include "ccid.h" 22 #include "dccp.h" 23 #include "feat.h" 24 25 int dccp_feat_default_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW; 26 int dccp_feat_default_rx_ccid = DCCPF_INITIAL_CCID; 27 int dccp_feat_default_tx_ccid = DCCPF_INITIAL_CCID; 28 int dccp_feat_default_ack_ratio = DCCPF_INITIAL_ACK_RATIO; 29 int dccp_feat_default_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR; 30 int dccp_feat_default_send_ndp_count = DCCPF_INITIAL_SEND_NDP_COUNT; 31 32 void dccp_minisock_init(struct dccp_minisock *dmsk) 33 { 34 dmsk->dccpms_sequence_window = dccp_feat_default_sequence_window; 35 dmsk->dccpms_rx_ccid = dccp_feat_default_rx_ccid; 36 dmsk->dccpms_tx_ccid = dccp_feat_default_tx_ccid; 37 dmsk->dccpms_ack_ratio = dccp_feat_default_ack_ratio; 38 dmsk->dccpms_send_ack_vector = dccp_feat_default_send_ack_vector; 39 dmsk->dccpms_send_ndp_count = dccp_feat_default_send_ndp_count; 40 } 41 42 static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len) 43 { 44 u32 value = 0; 45 46 if (len > 3) 47 value += *bf++ << 24; 48 if (len > 2) 49 value += *bf++ << 16; 50 if (len > 1) 51 value += *bf++ << 8; 52 if (len > 0) 53 value += *bf; 54 55 return value; 56 } 57 58 int dccp_parse_options(struct sock *sk, struct sk_buff *skb) 59 { 60 struct dccp_sock *dp = dccp_sk(sk); 61 #ifdef CONFIG_IP_DCCP_DEBUG 62 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ? 63 "CLIENT rx opt: " : "server rx opt: "; 64 #endif 65 const struct dccp_hdr *dh = dccp_hdr(skb); 66 const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type; 67 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb); 68 unsigned char *opt_ptr = options; 69 const unsigned char *opt_end = (unsigned char *)dh + 70 (dh->dccph_doff * 4); 71 struct dccp_options_received *opt_recv = &dp->dccps_options_received; 72 unsigned char opt, len; 73 unsigned char *value; 74 u32 elapsed_time; 75 int rc; 76 int mandatory = 0; 77 78 memset(opt_recv, 0, sizeof(*opt_recv)); 79 80 opt = len = 0; 81 while (opt_ptr != opt_end) { 82 opt = *opt_ptr++; 83 len = 0; 84 value = NULL; 85 86 /* Check if this isn't a single byte option */ 87 if (opt > DCCPO_MAX_RESERVED) { 88 if (opt_ptr == opt_end) 89 goto out_invalid_option; 90 91 len = *opt_ptr++; 92 if (len < 3) 93 goto out_invalid_option; 94 /* 95 * Remove the type and len fields, leaving 96 * just the value size 97 */ 98 len -= 2; 99 value = opt_ptr; 100 opt_ptr += len; 101 102 if (opt_ptr > opt_end) 103 goto out_invalid_option; 104 } 105 106 switch (opt) { 107 case DCCPO_PADDING: 108 break; 109 case DCCPO_MANDATORY: 110 if (mandatory) 111 goto out_invalid_option; 112 if (pkt_type != DCCP_PKT_DATA) 113 mandatory = 1; 114 break; 115 case DCCPO_NDP_COUNT: 116 if (len > 3) 117 goto out_invalid_option; 118 119 opt_recv->dccpor_ndp = dccp_decode_value_var(value, len); 120 dccp_pr_debug("%sNDP count=%d\n", debug_prefix, 121 opt_recv->dccpor_ndp); 122 break; 123 case DCCPO_CHANGE_L: 124 /* fall through */ 125 case DCCPO_CHANGE_R: 126 if (len < 2) 127 goto out_invalid_option; 128 rc = dccp_feat_change_recv(sk, opt, *value, value + 1, 129 len - 1); 130 /* 131 * When there is a change error, change_recv is 132 * responsible for dealing with it. i.e. reply with an 133 * empty confirm. 134 * If the change was mandatory, then we need to die. 135 */ 136 if (rc && mandatory) 137 goto out_invalid_option; 138 break; 139 case DCCPO_CONFIRM_L: 140 /* fall through */ 141 case DCCPO_CONFIRM_R: 142 if (len < 2) 143 goto out_invalid_option; 144 if (dccp_feat_confirm_recv(sk, opt, *value, 145 value + 1, len - 1)) 146 goto out_invalid_option; 147 break; 148 case DCCPO_ACK_VECTOR_0: 149 case DCCPO_ACK_VECTOR_1: 150 if (pkt_type == DCCP_PKT_DATA) 151 break; 152 153 if (dccp_msk(sk)->dccpms_send_ack_vector && 154 dccp_ackvec_parse(sk, skb, opt, value, len)) 155 goto out_invalid_option; 156 break; 157 case DCCPO_TIMESTAMP: 158 if (len != 4) 159 goto out_invalid_option; 160 161 opt_recv->dccpor_timestamp = ntohl(*(__be32 *)value); 162 163 dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp; 164 dccp_timestamp(sk, &dp->dccps_timestamp_time); 165 166 dccp_pr_debug("%sTIMESTAMP=%u, ackno=%llu\n", 167 debug_prefix, opt_recv->dccpor_timestamp, 168 (unsigned long long) 169 DCCP_SKB_CB(skb)->dccpd_ack_seq); 170 break; 171 case DCCPO_TIMESTAMP_ECHO: 172 if (len != 4 && len != 6 && len != 8) 173 goto out_invalid_option; 174 175 opt_recv->dccpor_timestamp_echo = ntohl(*(__be32 *)value); 176 177 dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, ackno=%llu, ", 178 debug_prefix, 179 opt_recv->dccpor_timestamp_echo, 180 len + 2, 181 (unsigned long long) 182 DCCP_SKB_CB(skb)->dccpd_ack_seq); 183 184 185 if (len == 4) 186 break; 187 188 if (len == 6) 189 elapsed_time = ntohs(*(__be16 *)(value + 4)); 190 else 191 elapsed_time = ntohl(*(__be32 *)(value + 4)); 192 193 /* Give precedence to the biggest ELAPSED_TIME */ 194 if (elapsed_time > opt_recv->dccpor_elapsed_time) 195 opt_recv->dccpor_elapsed_time = elapsed_time; 196 break; 197 case DCCPO_ELAPSED_TIME: 198 if (len != 2 && len != 4) 199 goto out_invalid_option; 200 201 if (pkt_type == DCCP_PKT_DATA) 202 continue; 203 204 if (len == 2) 205 elapsed_time = ntohs(*(__be16 *)value); 206 else 207 elapsed_time = ntohl(*(__be32 *)value); 208 209 if (elapsed_time > opt_recv->dccpor_elapsed_time) 210 opt_recv->dccpor_elapsed_time = elapsed_time; 211 212 dccp_pr_debug("%sELAPSED_TIME=%d\n", debug_prefix, 213 elapsed_time); 214 break; 215 /* 216 * From draft-ietf-dccp-spec-11.txt: 217 * 218 * Option numbers 128 through 191 are for 219 * options sent from the HC-Sender to the 220 * HC-Receiver; option numbers 192 through 255 221 * are for options sent from the HC-Receiver to 222 * the HC-Sender. 223 */ 224 case 128 ... 191: { 225 const u16 idx = value - options; 226 227 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk, 228 opt, len, idx, 229 value) != 0) 230 goto out_invalid_option; 231 } 232 break; 233 case 192 ... 255: { 234 const u16 idx = value - options; 235 236 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk, 237 opt, len, idx, 238 value) != 0) 239 goto out_invalid_option; 240 } 241 break; 242 default: 243 pr_info("DCCP(%p): option %d(len=%d) not " 244 "implemented, ignoring\n", 245 sk, opt, len); 246 break; 247 } 248 249 if (opt != DCCPO_MANDATORY) 250 mandatory = 0; 251 } 252 253 /* mandatory was the last byte in option list -> reset connection */ 254 if (mandatory) 255 goto out_invalid_option; 256 257 return 0; 258 259 out_invalid_option: 260 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT); 261 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR; 262 pr_info("DCCP(%p): invalid option %d, len=%d\n", sk, opt, len); 263 return -1; 264 } 265 266 EXPORT_SYMBOL_GPL(dccp_parse_options); 267 268 static void dccp_encode_value_var(const u32 value, unsigned char *to, 269 const unsigned int len) 270 { 271 if (len > 3) 272 *to++ = (value & 0xFF000000) >> 24; 273 if (len > 2) 274 *to++ = (value & 0xFF0000) >> 16; 275 if (len > 1) 276 *to++ = (value & 0xFF00) >> 8; 277 if (len > 0) 278 *to++ = (value & 0xFF); 279 } 280 281 static inline int dccp_ndp_len(const int ndp) 282 { 283 return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3; 284 } 285 286 int dccp_insert_option(struct sock *sk, struct sk_buff *skb, 287 const unsigned char option, 288 const void *value, const unsigned char len) 289 { 290 unsigned char *to; 291 292 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN) 293 return -1; 294 295 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2; 296 297 to = skb_push(skb, len + 2); 298 *to++ = option; 299 *to++ = len + 2; 300 301 memcpy(to, value, len); 302 return 0; 303 } 304 305 EXPORT_SYMBOL_GPL(dccp_insert_option); 306 307 static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb) 308 { 309 struct dccp_sock *dp = dccp_sk(sk); 310 int ndp = dp->dccps_ndp_count; 311 312 if (dccp_non_data_packet(skb)) 313 ++dp->dccps_ndp_count; 314 else 315 dp->dccps_ndp_count = 0; 316 317 if (ndp > 0) { 318 unsigned char *ptr; 319 const int ndp_len = dccp_ndp_len(ndp); 320 const int len = ndp_len + 2; 321 322 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) 323 return -1; 324 325 DCCP_SKB_CB(skb)->dccpd_opt_len += len; 326 327 ptr = skb_push(skb, len); 328 *ptr++ = DCCPO_NDP_COUNT; 329 *ptr++ = len; 330 dccp_encode_value_var(ndp, ptr, ndp_len); 331 } 332 333 return 0; 334 } 335 336 static inline int dccp_elapsed_time_len(const u32 elapsed_time) 337 { 338 return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4; 339 } 340 341 int dccp_insert_option_elapsed_time(struct sock *sk, struct sk_buff *skb, 342 u32 elapsed_time) 343 { 344 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time); 345 const int len = 2 + elapsed_time_len; 346 unsigned char *to; 347 348 if (elapsed_time_len == 0) 349 return 0; 350 351 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) 352 return -1; 353 354 DCCP_SKB_CB(skb)->dccpd_opt_len += len; 355 356 to = skb_push(skb, len); 357 *to++ = DCCPO_ELAPSED_TIME; 358 *to++ = len; 359 360 if (elapsed_time_len == 2) { 361 const __be16 var16 = htons((u16)elapsed_time); 362 memcpy(to, &var16, 2); 363 } else { 364 const __be32 var32 = htonl(elapsed_time); 365 memcpy(to, &var32, 4); 366 } 367 368 return 0; 369 } 370 371 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time); 372 373 void dccp_timestamp(const struct sock *sk, struct timeval *tv) 374 { 375 const struct dccp_sock *dp = dccp_sk(sk); 376 377 do_gettimeofday(tv); 378 tv->tv_sec -= dp->dccps_epoch.tv_sec; 379 tv->tv_usec -= dp->dccps_epoch.tv_usec; 380 381 while (tv->tv_usec < 0) { 382 tv->tv_sec--; 383 tv->tv_usec += USEC_PER_SEC; 384 } 385 } 386 387 EXPORT_SYMBOL_GPL(dccp_timestamp); 388 389 int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb) 390 { 391 struct timeval tv; 392 __be32 now; 393 394 dccp_timestamp(sk, &tv); 395 now = htonl(timeval_usecs(&tv) / 10); 396 /* yes this will overflow but that is the point as we want a 397 * 10 usec 32 bit timer which mean it wraps every 11.9 hours */ 398 399 return dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now)); 400 } 401 402 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp); 403 404 static int dccp_insert_option_timestamp_echo(struct sock *sk, 405 struct sk_buff *skb) 406 { 407 struct dccp_sock *dp = dccp_sk(sk); 408 struct timeval now; 409 __be32 tstamp_echo; 410 u32 elapsed_time; 411 int len, elapsed_time_len; 412 unsigned char *to; 413 414 dccp_timestamp(sk, &now); 415 elapsed_time = timeval_delta(&now, &dp->dccps_timestamp_time) / 10; 416 elapsed_time_len = dccp_elapsed_time_len(elapsed_time); 417 len = 6 + elapsed_time_len; 418 419 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) 420 return -1; 421 422 DCCP_SKB_CB(skb)->dccpd_opt_len += len; 423 424 to = skb_push(skb, len); 425 *to++ = DCCPO_TIMESTAMP_ECHO; 426 *to++ = len; 427 428 tstamp_echo = htonl(dp->dccps_timestamp_echo); 429 memcpy(to, &tstamp_echo, 4); 430 to += 4; 431 432 if (elapsed_time_len == 2) { 433 const __be16 var16 = htons((u16)elapsed_time); 434 memcpy(to, &var16, 2); 435 } else if (elapsed_time_len == 4) { 436 const __be32 var32 = htonl(elapsed_time); 437 memcpy(to, &var32, 4); 438 } 439 440 dp->dccps_timestamp_echo = 0; 441 dp->dccps_timestamp_time.tv_sec = 0; 442 dp->dccps_timestamp_time.tv_usec = 0; 443 return 0; 444 } 445 446 static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat, 447 u8 *val, u8 len) 448 { 449 u8 *to; 450 451 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 3 > DCCP_MAX_OPT_LEN) { 452 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small" 453 " to insert feature %d option!\n", feat); 454 return -1; 455 } 456 457 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3; 458 459 to = skb_push(skb, len + 3); 460 *to++ = type; 461 *to++ = len + 3; 462 *to++ = feat; 463 464 if (len) 465 memcpy(to, val, len); 466 dccp_pr_debug("option %d feat %d len %d\n", type, feat, len); 467 468 return 0; 469 } 470 471 static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb) 472 { 473 struct dccp_sock *dp = dccp_sk(sk); 474 struct dccp_minisock *dmsk = dccp_msk(sk); 475 struct dccp_opt_pend *opt, *next; 476 int change = 0; 477 478 /* confirm any options [NN opts] */ 479 list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) { 480 dccp_insert_feat_opt(skb, opt->dccpop_type, 481 opt->dccpop_feat, opt->dccpop_val, 482 opt->dccpop_len); 483 /* fear empty confirms */ 484 if (opt->dccpop_val) 485 kfree(opt->dccpop_val); 486 kfree(opt); 487 } 488 INIT_LIST_HEAD(&dmsk->dccpms_conf); 489 490 /* see which features we need to send */ 491 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { 492 /* see if we need to send any confirm */ 493 if (opt->dccpop_sc) { 494 dccp_insert_feat_opt(skb, opt->dccpop_type + 1, 495 opt->dccpop_feat, 496 opt->dccpop_sc->dccpoc_val, 497 opt->dccpop_sc->dccpoc_len); 498 499 BUG_ON(!opt->dccpop_sc->dccpoc_val); 500 kfree(opt->dccpop_sc->dccpoc_val); 501 kfree(opt->dccpop_sc); 502 opt->dccpop_sc = NULL; 503 } 504 505 /* any option not confirmed, re-send it */ 506 if (!opt->dccpop_conf) { 507 dccp_insert_feat_opt(skb, opt->dccpop_type, 508 opt->dccpop_feat, opt->dccpop_val, 509 opt->dccpop_len); 510 change++; 511 } 512 } 513 514 /* Retransmit timer. 515 * If this is the master listening sock, we don't set a timer on it. It 516 * should be fine because if the dude doesn't receive our RESPONSE 517 * [which will contain the CHANGE] he will send another REQUEST which 518 * will "retrnasmit" the change. 519 */ 520 if (change && dp->dccps_role != DCCP_ROLE_LISTEN) { 521 dccp_pr_debug("reset feat negotiation timer %p\n", sk); 522 523 /* XXX don't reset the timer on re-transmissions. I.e. reset it 524 * only when sending new stuff i guess. Currently the timer 525 * never backs off because on re-transmission it just resets it! 526 */ 527 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, 528 inet_csk(sk)->icsk_rto, DCCP_RTO_MAX); 529 } 530 531 return 0; 532 } 533 534 int dccp_insert_options(struct sock *sk, struct sk_buff *skb) 535 { 536 struct dccp_sock *dp = dccp_sk(sk); 537 struct dccp_minisock *dmsk = dccp_msk(sk); 538 539 DCCP_SKB_CB(skb)->dccpd_opt_len = 0; 540 541 if (dmsk->dccpms_send_ndp_count && 542 dccp_insert_option_ndp(sk, skb)) 543 return -1; 544 545 if (!dccp_packet_without_ack(skb)) { 546 if (dmsk->dccpms_send_ack_vector && 547 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) && 548 dccp_insert_option_ackvec(sk, skb)) 549 return -1; 550 551 if (dp->dccps_timestamp_echo != 0 && 552 dccp_insert_option_timestamp_echo(sk, skb)) 553 return -1; 554 } 555 556 if (dp->dccps_hc_rx_insert_options) { 557 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb)) 558 return -1; 559 dp->dccps_hc_rx_insert_options = 0; 560 } 561 if (dp->dccps_hc_tx_insert_options) { 562 if (ccid_hc_tx_insert_options(dp->dccps_hc_tx_ccid, sk, skb)) 563 return -1; 564 dp->dccps_hc_tx_insert_options = 0; 565 } 566 567 /* Feature negotiation */ 568 /* Data packets can't do feat negotiation */ 569 if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA && 570 DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATAACK && 571 dccp_insert_options_feat(sk, skb)) 572 return -1; 573 574 /* XXX: insert other options when appropriate */ 575 576 if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) { 577 /* The length of all options has to be a multiple of 4 */ 578 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4; 579 580 if (padding != 0) { 581 padding = 4 - padding; 582 memset(skb_push(skb, padding), 0, padding); 583 DCCP_SKB_CB(skb)->dccpd_opt_len += padding; 584 } 585 } 586 587 return 0; 588 } 589