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 <ian.mcdonald@jandi.co.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 sysctl_dccp_feat_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW; 26 int sysctl_dccp_feat_rx_ccid = DCCPF_INITIAL_CCID; 27 int sysctl_dccp_feat_tx_ccid = DCCPF_INITIAL_CCID; 28 int sysctl_dccp_feat_ack_ratio = DCCPF_INITIAL_ACK_RATIO; 29 int sysctl_dccp_feat_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR; 30 int sysctl_dccp_feat_send_ndp_count = DCCPF_INITIAL_SEND_NDP_COUNT; 31 32 EXPORT_SYMBOL_GPL(sysctl_dccp_feat_sequence_window); 33 34 void dccp_minisock_init(struct dccp_minisock *dmsk) 35 { 36 dmsk->dccpms_sequence_window = sysctl_dccp_feat_sequence_window; 37 dmsk->dccpms_rx_ccid = sysctl_dccp_feat_rx_ccid; 38 dmsk->dccpms_tx_ccid = sysctl_dccp_feat_tx_ccid; 39 dmsk->dccpms_ack_ratio = sysctl_dccp_feat_ack_ratio; 40 dmsk->dccpms_send_ack_vector = sysctl_dccp_feat_send_ack_vector; 41 dmsk->dccpms_send_ndp_count = sysctl_dccp_feat_send_ndp_count; 42 } 43 44 static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len) 45 { 46 u32 value = 0; 47 48 if (len > 3) 49 value += *bf++ << 24; 50 if (len > 2) 51 value += *bf++ << 16; 52 if (len > 1) 53 value += *bf++ << 8; 54 if (len > 0) 55 value += *bf; 56 57 return value; 58 } 59 60 int dccp_parse_options(struct sock *sk, struct sk_buff *skb) 61 { 62 struct dccp_sock *dp = dccp_sk(sk); 63 const struct dccp_hdr *dh = dccp_hdr(skb); 64 const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type; 65 u64 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; 66 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb); 67 unsigned char *opt_ptr = options; 68 const unsigned char *opt_end = (unsigned char *)dh + 69 (dh->dccph_doff * 4); 70 struct dccp_options_received *opt_recv = &dp->dccps_options_received; 71 unsigned char opt, len; 72 unsigned char *value; 73 u32 elapsed_time; 74 int rc; 75 int mandatory = 0; 76 77 memset(opt_recv, 0, sizeof(*opt_recv)); 78 79 opt = len = 0; 80 while (opt_ptr != opt_end) { 81 opt = *opt_ptr++; 82 len = 0; 83 value = NULL; 84 85 /* Check if this isn't a single byte option */ 86 if (opt > DCCPO_MAX_RESERVED) { 87 if (opt_ptr == opt_end) 88 goto out_invalid_option; 89 90 len = *opt_ptr++; 91 if (len < 3) 92 goto out_invalid_option; 93 /* 94 * Remove the type and len fields, leaving 95 * just the value size 96 */ 97 len -= 2; 98 value = opt_ptr; 99 opt_ptr += len; 100 101 if (opt_ptr > opt_end) 102 goto out_invalid_option; 103 } 104 105 switch (opt) { 106 case DCCPO_PADDING: 107 break; 108 case DCCPO_MANDATORY: 109 if (mandatory) 110 goto out_invalid_option; 111 if (pkt_type != DCCP_PKT_DATA) 112 mandatory = 1; 113 break; 114 case DCCPO_NDP_COUNT: 115 if (len > 3) 116 goto out_invalid_option; 117 118 opt_recv->dccpor_ndp = dccp_decode_value_var(value, len); 119 dccp_pr_debug("%s rx opt: NDP count=%d\n", dccp_role(sk), 120 opt_recv->dccpor_ndp); 121 break; 122 case DCCPO_CHANGE_L: 123 /* fall through */ 124 case DCCPO_CHANGE_R: 125 if (len < 2) 126 goto out_invalid_option; 127 rc = dccp_feat_change_recv(sk, opt, *value, value + 1, 128 len - 1); 129 /* 130 * When there is a change error, change_recv is 131 * responsible for dealing with it. i.e. reply with an 132 * empty confirm. 133 * If the change was mandatory, then we need to die. 134 */ 135 if (rc && mandatory) 136 goto out_invalid_option; 137 break; 138 case DCCPO_CONFIRM_L: 139 /* fall through */ 140 case DCCPO_CONFIRM_R: 141 if (len < 2) 142 goto out_invalid_option; 143 if (dccp_feat_confirm_recv(sk, opt, *value, 144 value + 1, len - 1)) 145 goto out_invalid_option; 146 break; 147 case DCCPO_ACK_VECTOR_0: 148 case DCCPO_ACK_VECTOR_1: 149 if (pkt_type == DCCP_PKT_DATA) 150 break; 151 152 if (dccp_msk(sk)->dccpms_send_ack_vector && 153 dccp_ackvec_parse(sk, skb, &ackno, opt, value, len)) 154 goto out_invalid_option; 155 break; 156 case DCCPO_TIMESTAMP: 157 if (len != 4) 158 goto out_invalid_option; 159 160 opt_recv->dccpor_timestamp = ntohl(*(__be32 *)value); 161 162 dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp; 163 dccp_timestamp(sk, &dp->dccps_timestamp_time); 164 165 dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n", 166 dccp_role(sk), opt_recv->dccpor_timestamp, 167 (unsigned long long) 168 DCCP_SKB_CB(skb)->dccpd_ack_seq); 169 break; 170 case DCCPO_TIMESTAMP_ECHO: 171 if (len != 4 && len != 6 && len != 8) 172 goto out_invalid_option; 173 174 opt_recv->dccpor_timestamp_echo = ntohl(*(__be32 *)value); 175 176 dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, " 177 "ackno=%llu, ", dccp_role(sk), 178 opt_recv->dccpor_timestamp_echo, 179 len + 2, 180 (unsigned long long) 181 DCCP_SKB_CB(skb)->dccpd_ack_seq); 182 183 184 if (len == 4) 185 break; 186 187 if (len == 6) 188 elapsed_time = ntohs(*(__be16 *)(value + 4)); 189 else 190 elapsed_time = ntohl(*(__be32 *)(value + 4)); 191 192 /* Give precedence to the biggest ELAPSED_TIME */ 193 if (elapsed_time > opt_recv->dccpor_elapsed_time) 194 opt_recv->dccpor_elapsed_time = elapsed_time; 195 break; 196 case DCCPO_ELAPSED_TIME: 197 if (len != 2 && len != 4) 198 goto out_invalid_option; 199 200 if (pkt_type == DCCP_PKT_DATA) 201 continue; 202 203 if (len == 2) 204 elapsed_time = ntohs(*(__be16 *)value); 205 else 206 elapsed_time = ntohl(*(__be32 *)value); 207 208 if (elapsed_time > opt_recv->dccpor_elapsed_time) 209 opt_recv->dccpor_elapsed_time = elapsed_time; 210 211 dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n", 212 dccp_role(sk), elapsed_time); 213 break; 214 /* 215 * From RFC 4340, sec. 10.3: 216 * 217 * Option numbers 128 through 191 are for 218 * options sent from the HC-Sender to the 219 * HC-Receiver; option numbers 192 through 255 220 * are for options sent from the HC-Receiver to 221 * the HC-Sender. 222 */ 223 case 128 ... 191: { 224 const u16 idx = value - options; 225 226 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk, 227 opt, len, idx, 228 value) != 0) 229 goto out_invalid_option; 230 } 231 break; 232 case 192 ... 255: { 233 const u16 idx = value - options; 234 235 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk, 236 opt, len, idx, 237 value) != 0) 238 goto out_invalid_option; 239 } 240 break; 241 default: 242 DCCP_CRIT("DCCP(%p): option %d(len=%d) not " 243 "implemented, ignoring", sk, opt, len); 244 break; 245 } 246 247 if (opt != DCCPO_MANDATORY) 248 mandatory = 0; 249 } 250 251 /* mandatory was the last byte in option list -> reset connection */ 252 if (mandatory) 253 goto out_invalid_option; 254 255 return 0; 256 257 out_invalid_option: 258 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT); 259 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR; 260 DCCP_WARN("DCCP(%p): invalid option %d, len=%d", sk, opt, len); 261 return -1; 262 } 263 264 EXPORT_SYMBOL_GPL(dccp_parse_options); 265 266 static void dccp_encode_value_var(const u32 value, unsigned char *to, 267 const unsigned int len) 268 { 269 if (len > 3) 270 *to++ = (value & 0xFF000000) >> 24; 271 if (len > 2) 272 *to++ = (value & 0xFF0000) >> 16; 273 if (len > 1) 274 *to++ = (value & 0xFF00) >> 8; 275 if (len > 0) 276 *to++ = (value & 0xFF); 277 } 278 279 static inline int dccp_ndp_len(const int ndp) 280 { 281 return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3; 282 } 283 284 int dccp_insert_option(struct sock *sk, struct sk_buff *skb, 285 const unsigned char option, 286 const void *value, const unsigned char len) 287 { 288 unsigned char *to; 289 290 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN) 291 return -1; 292 293 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2; 294 295 to = skb_push(skb, len + 2); 296 *to++ = option; 297 *to++ = len + 2; 298 299 memcpy(to, value, len); 300 return 0; 301 } 302 303 EXPORT_SYMBOL_GPL(dccp_insert_option); 304 305 static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb) 306 { 307 struct dccp_sock *dp = dccp_sk(sk); 308 int ndp = dp->dccps_ndp_count; 309 310 if (dccp_non_data_packet(skb)) 311 ++dp->dccps_ndp_count; 312 else 313 dp->dccps_ndp_count = 0; 314 315 if (ndp > 0) { 316 unsigned char *ptr; 317 const int ndp_len = dccp_ndp_len(ndp); 318 const int len = ndp_len + 2; 319 320 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) 321 return -1; 322 323 DCCP_SKB_CB(skb)->dccpd_opt_len += len; 324 325 ptr = skb_push(skb, len); 326 *ptr++ = DCCPO_NDP_COUNT; 327 *ptr++ = len; 328 dccp_encode_value_var(ndp, ptr, ndp_len); 329 } 330 331 return 0; 332 } 333 334 static inline int dccp_elapsed_time_len(const u32 elapsed_time) 335 { 336 return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4; 337 } 338 339 int dccp_insert_option_elapsed_time(struct sock *sk, struct sk_buff *skb, 340 u32 elapsed_time) 341 { 342 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time); 343 const int len = 2 + elapsed_time_len; 344 unsigned char *to; 345 346 if (elapsed_time_len == 0) 347 return 0; 348 349 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) 350 return -1; 351 352 DCCP_SKB_CB(skb)->dccpd_opt_len += len; 353 354 to = skb_push(skb, len); 355 *to++ = DCCPO_ELAPSED_TIME; 356 *to++ = len; 357 358 if (elapsed_time_len == 2) { 359 const __be16 var16 = htons((u16)elapsed_time); 360 memcpy(to, &var16, 2); 361 } else { 362 const __be32 var32 = htonl(elapsed_time); 363 memcpy(to, &var32, 4); 364 } 365 366 return 0; 367 } 368 369 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time); 370 371 void dccp_timestamp(const struct sock *sk, struct timeval *tv) 372 { 373 const struct dccp_sock *dp = dccp_sk(sk); 374 375 do_gettimeofday(tv); 376 tv->tv_sec -= dp->dccps_epoch.tv_sec; 377 tv->tv_usec -= dp->dccps_epoch.tv_usec; 378 379 while (tv->tv_usec < 0) { 380 tv->tv_sec--; 381 tv->tv_usec += USEC_PER_SEC; 382 } 383 } 384 385 EXPORT_SYMBOL_GPL(dccp_timestamp); 386 387 int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb) 388 { 389 struct timeval tv; 390 __be32 now; 391 392 dccp_timestamp(sk, &tv); 393 now = htonl(timeval_usecs(&tv) / 10); 394 /* yes this will overflow but that is the point as we want a 395 * 10 usec 32 bit timer which mean it wraps every 11.9 hours */ 396 397 return dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now)); 398 } 399 400 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp); 401 402 static int dccp_insert_option_timestamp_echo(struct sock *sk, 403 struct sk_buff *skb) 404 { 405 struct dccp_sock *dp = dccp_sk(sk); 406 struct timeval now; 407 __be32 tstamp_echo; 408 u32 elapsed_time; 409 int len, elapsed_time_len; 410 unsigned char *to; 411 412 dccp_timestamp(sk, &now); 413 elapsed_time = timeval_delta(&now, &dp->dccps_timestamp_time) / 10; 414 elapsed_time_len = dccp_elapsed_time_len(elapsed_time); 415 len = 6 + elapsed_time_len; 416 417 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) 418 return -1; 419 420 DCCP_SKB_CB(skb)->dccpd_opt_len += len; 421 422 to = skb_push(skb, len); 423 *to++ = DCCPO_TIMESTAMP_ECHO; 424 *to++ = len; 425 426 tstamp_echo = htonl(dp->dccps_timestamp_echo); 427 memcpy(to, &tstamp_echo, 4); 428 to += 4; 429 430 if (elapsed_time_len == 2) { 431 const __be16 var16 = htons((u16)elapsed_time); 432 memcpy(to, &var16, 2); 433 } else if (elapsed_time_len == 4) { 434 const __be32 var32 = htonl(elapsed_time); 435 memcpy(to, &var32, 4); 436 } 437 438 dp->dccps_timestamp_echo = 0; 439 dp->dccps_timestamp_time.tv_sec = 0; 440 dp->dccps_timestamp_time.tv_usec = 0; 441 return 0; 442 } 443 444 static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat, 445 u8 *val, u8 len) 446 { 447 u8 *to; 448 449 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 3 > DCCP_MAX_OPT_LEN) { 450 DCCP_WARN("packet too small for feature %d option!\n", feat); 451 return -1; 452 } 453 454 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3; 455 456 to = skb_push(skb, len + 3); 457 *to++ = type; 458 *to++ = len + 3; 459 *to++ = feat; 460 461 if (len) 462 memcpy(to, val, len); 463 464 dccp_pr_debug("%s(%s (%d), ...), length %d\n", 465 dccp_feat_typename(type), 466 dccp_feat_name(feat), feat, len); 467 return 0; 468 } 469 470 static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb) 471 { 472 struct dccp_sock *dp = dccp_sk(sk); 473 struct dccp_minisock *dmsk = dccp_msk(sk); 474 struct dccp_opt_pend *opt, *next; 475 int change = 0; 476 477 /* confirm any options [NN opts] */ 478 list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) { 479 dccp_insert_feat_opt(skb, opt->dccpop_type, 480 opt->dccpop_feat, opt->dccpop_val, 481 opt->dccpop_len); 482 /* fear empty confirms */ 483 if (opt->dccpop_val) 484 kfree(opt->dccpop_val); 485 kfree(opt); 486 } 487 INIT_LIST_HEAD(&dmsk->dccpms_conf); 488 489 /* see which features we need to send */ 490 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { 491 /* see if we need to send any confirm */ 492 if (opt->dccpop_sc) { 493 dccp_insert_feat_opt(skb, opt->dccpop_type + 1, 494 opt->dccpop_feat, 495 opt->dccpop_sc->dccpoc_val, 496 opt->dccpop_sc->dccpoc_len); 497 498 BUG_ON(!opt->dccpop_sc->dccpoc_val); 499 kfree(opt->dccpop_sc->dccpoc_val); 500 kfree(opt->dccpop_sc); 501 opt->dccpop_sc = NULL; 502 } 503 504 /* any option not confirmed, re-send it */ 505 if (!opt->dccpop_conf) { 506 dccp_insert_feat_opt(skb, opt->dccpop_type, 507 opt->dccpop_feat, opt->dccpop_val, 508 opt->dccpop_len); 509 change++; 510 } 511 } 512 513 /* Retransmit timer. 514 * If this is the master listening sock, we don't set a timer on it. It 515 * should be fine because if the dude doesn't receive our RESPONSE 516 * [which will contain the CHANGE] he will send another REQUEST which 517 * will "retrnasmit" the change. 518 */ 519 if (change && dp->dccps_role != DCCP_ROLE_LISTEN) { 520 dccp_pr_debug("reset feat negotiation timer %p\n", sk); 521 522 /* XXX don't reset the timer on re-transmissions. I.e. reset it 523 * only when sending new stuff i guess. Currently the timer 524 * never backs off because on re-transmission it just resets it! 525 */ 526 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, 527 inet_csk(sk)->icsk_rto, DCCP_RTO_MAX); 528 } 529 530 return 0; 531 } 532 533 int dccp_insert_options(struct sock *sk, struct sk_buff *skb) 534 { 535 struct dccp_sock *dp = dccp_sk(sk); 536 struct dccp_minisock *dmsk = dccp_msk(sk); 537 538 DCCP_SKB_CB(skb)->dccpd_opt_len = 0; 539 540 if (dmsk->dccpms_send_ndp_count && 541 dccp_insert_option_ndp(sk, skb)) 542 return -1; 543 544 if (!dccp_packet_without_ack(skb)) { 545 if (dmsk->dccpms_send_ack_vector && 546 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) && 547 dccp_insert_option_ackvec(sk, skb)) 548 return -1; 549 550 if (dp->dccps_timestamp_echo != 0 && 551 dccp_insert_option_timestamp_echo(sk, skb)) 552 return -1; 553 } 554 555 if (dp->dccps_hc_rx_insert_options) { 556 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb)) 557 return -1; 558 dp->dccps_hc_rx_insert_options = 0; 559 } 560 if (dp->dccps_hc_tx_insert_options) { 561 if (ccid_hc_tx_insert_options(dp->dccps_hc_tx_ccid, sk, skb)) 562 return -1; 563 dp->dccps_hc_tx_insert_options = 0; 564 } 565 566 /* Feature negotiation */ 567 /* Data packets can't do feat negotiation */ 568 if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA && 569 DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATAACK && 570 dccp_insert_options_feat(sk, skb)) 571 return -1; 572 573 /* XXX: insert other options when appropriate */ 574 575 if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) { 576 /* The length of all options has to be a multiple of 4 */ 577 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4; 578 579 if (padding != 0) { 580 padding = 4 - padding; 581 memset(skb_push(skb, padding), 0, padding); 582 DCCP_SKB_CB(skb)->dccpd_opt_len += padding; 583 } 584 } 585 586 return 0; 587 } 588