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 25int sysctl_dccp_feat_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW; 26int sysctl_dccp_feat_rx_ccid = DCCPF_INITIAL_CCID; 27int sysctl_dccp_feat_tx_ccid = DCCPF_INITIAL_CCID; 28int sysctl_dccp_feat_ack_ratio = DCCPF_INITIAL_ACK_RATIO; 29int sysctl_dccp_feat_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR; 30int sysctl_dccp_feat_send_ndp_count = DCCPF_INITIAL_SEND_NDP_COUNT; 31 32void dccp_minisock_init(struct dccp_minisock *dmsk) 33{ 34 dmsk->dccpms_sequence_window = sysctl_dccp_feat_sequence_window; 35 dmsk->dccpms_rx_ccid = sysctl_dccp_feat_rx_ccid; 36 dmsk->dccpms_tx_ccid = sysctl_dccp_feat_tx_ccid; 37 dmsk->dccpms_ack_ratio = sysctl_dccp_feat_ack_ratio; 38 dmsk->dccpms_send_ack_vector = sysctl_dccp_feat_send_ack_vector; 39 dmsk->dccpms_send_ndp_count = sysctl_dccp_feat_send_ndp_count; 40} 41 42static 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 58int dccp_parse_options(struct sock *sk, struct sk_buff *skb) 59{ 60 struct dccp_sock *dp = dccp_sk(sk); 61 const struct dccp_hdr *dh = dccp_hdr(skb); 62 const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type; 63 u64 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; 64 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb); 65 unsigned char *opt_ptr = options; 66 const unsigned char *opt_end = (unsigned char *)dh + 67 (dh->dccph_doff * 4); 68 struct dccp_options_received *opt_recv = &dp->dccps_options_received; 69 unsigned char opt, len; 70 unsigned char *value; 71 u32 elapsed_time; 72 int rc; 73 int mandatory = 0; 74 75 memset(opt_recv, 0, sizeof(*opt_recv)); 76 77 opt = len = 0; 78 while (opt_ptr != opt_end) { 79 opt = *opt_ptr++; 80 len = 0; 81 value = NULL; 82 83 /* Check if this isn't a single byte option */ 84 if (opt > DCCPO_MAX_RESERVED) { 85 if (opt_ptr == opt_end) 86 goto out_invalid_option; 87 88 len = *opt_ptr++; 89 if (len < 3) 90 goto out_invalid_option; 91 /* 92 * Remove the type and len fields, leaving 93 * just the value size 94 */ 95 len -= 2; 96 value = opt_ptr; 97 opt_ptr += len; 98 99 if (opt_ptr > opt_end) 100 goto out_invalid_option; 101 } 102 103 switch (opt) { 104 case DCCPO_PADDING: 105 break; 106 case DCCPO_MANDATORY: 107 if (mandatory) 108 goto out_invalid_option; 109 if (pkt_type != DCCP_PKT_DATA) 110 mandatory = 1; 111 break; 112 case DCCPO_NDP_COUNT: 113 if (len > 3) 114 goto out_invalid_option; 115 116 opt_recv->dccpor_ndp = dccp_decode_value_var(value, len); 117 dccp_pr_debug("%s rx opt: NDP count=%d\n", dccp_role(sk), 118 opt_recv->dccpor_ndp); 119 break; 120 case DCCPO_CHANGE_L: 121 /* fall through */ 122 case DCCPO_CHANGE_R: 123 if (len < 2) 124 goto out_invalid_option; 125 rc = dccp_feat_change_recv(sk, opt, *value, value + 1, 126 len - 1); 127 /* 128 * When there is a change error, change_recv is 129 * responsible for dealing with it. i.e. reply with an 130 * empty confirm. 131 * If the change was mandatory, then we need to die. 132 */ 133 if (rc && mandatory) 134 goto out_invalid_option; 135 break; 136 case DCCPO_CONFIRM_L: 137 /* fall through */ 138 case DCCPO_CONFIRM_R: 139 if (len < 2) 140 goto out_invalid_option; 141 if (dccp_feat_confirm_recv(sk, opt, *value, 142 value + 1, len - 1)) 143 goto out_invalid_option; 144 break; 145 case DCCPO_ACK_VECTOR_0: 146 case DCCPO_ACK_VECTOR_1: 147 if (pkt_type == DCCP_PKT_DATA) 148 break; 149 150 if (dccp_msk(sk)->dccpms_send_ack_vector && 151 dccp_ackvec_parse(sk, skb, &ackno, opt, value, len)) 152 goto out_invalid_option; 153 break; 154 case DCCPO_TIMESTAMP: 155 if (len != 4) 156 goto out_invalid_option; 157 158 opt_recv->dccpor_timestamp = ntohl(*(__be32 *)value); 159 160 dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp; 161 dccp_timestamp(sk, &dp->dccps_timestamp_time); 162 163 dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n", 164 dccp_role(sk), opt_recv->dccpor_timestamp, 165 (unsigned long long) 166 DCCP_SKB_CB(skb)->dccpd_ack_seq); 167 break; 168 case DCCPO_TIMESTAMP_ECHO: 169 if (len != 4 && len != 6 && len != 8) 170 goto out_invalid_option; 171 172 opt_recv->dccpor_timestamp_echo = ntohl(*(__be32 *)value); 173 174 dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, " 175 "ackno=%llu", dccp_role(sk), 176 opt_recv->dccpor_timestamp_echo, 177 len + 2, 178 (unsigned long long) 179 DCCP_SKB_CB(skb)->dccpd_ack_seq); 180 181 182 if (len == 4) { 183 dccp_pr_debug_cat("\n"); 184 break; 185 } 186 187 if (len == 6) 188 elapsed_time = ntohs(*(__be16 *)(value + 4)); 189 else 190 elapsed_time = ntohl(*(__be32 *)(value + 4)); 191 192 dccp_pr_debug_cat(", ELAPSED_TIME=%d\n", elapsed_time); 193 194 /* Give precedence to the biggest ELAPSED_TIME */ 195 if (elapsed_time > opt_recv->dccpor_elapsed_time) 196 opt_recv->dccpor_elapsed_time = elapsed_time; 197 break; 198 case DCCPO_ELAPSED_TIME: 199 if (len != 2 && len != 4) 200 goto out_invalid_option; 201 202 if (pkt_type == DCCP_PKT_DATA) 203 continue; 204 205 if (len == 2) 206 elapsed_time = ntohs(*(__be16 *)value); 207 else 208 elapsed_time = ntohl(*(__be32 *)value); 209 210 if (elapsed_time > opt_recv->dccpor_elapsed_time) 211 opt_recv->dccpor_elapsed_time = elapsed_time; 212 213 dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n", 214 dccp_role(sk), elapsed_time); 215 break; 216 /* 217 * From RFC 4340, sec. 10.3: 218 * 219 * Option numbers 128 through 191 are for 220 * options sent from the HC-Sender to the 221 * HC-Receiver; option numbers 192 through 255 222 * are for options sent from the HC-Receiver to 223 * the HC-Sender. 224 */ 225 case 128 ... 191: { 226 const u16 idx = value - options; 227 228 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk, 229 opt, len, idx, 230 value) != 0) 231 goto out_invalid_option; 232 } 233 break; 234 case 192 ... 255: { 235 const u16 idx = value - options; 236 237 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk, 238 opt, len, idx, 239 value) != 0) 240 goto out_invalid_option; 241 } 242 break; 243 default: 244 DCCP_CRIT("DCCP(%p): option %d(len=%d) not " 245 "implemented, ignoring", 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 259out_invalid_option: 260 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT); 261 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR; 262 DCCP_WARN("DCCP(%p): invalid option %d, len=%d", sk, opt, len); 263 return -1; 264} 265 266EXPORT_SYMBOL_GPL(dccp_parse_options); 267 268static 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 281static inline int dccp_ndp_len(const int ndp) 282{ 283 return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3; 284} 285 286int 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 305EXPORT_SYMBOL_GPL(dccp_insert_option); 306 307static 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 336static inline int dccp_elapsed_time_len(const u32 elapsed_time) 337{ 338 return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4; 339} 340 341int 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 371EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time); 372 373void 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 387EXPORT_SYMBOL_GPL(dccp_timestamp); 388 389int 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 402EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp); 403 404static 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 446static 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 DCCP_WARN("packet too small for feature %d option!\n", feat); 453 return -1; 454 } 455 456 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3; 457 458 to = skb_push(skb, len + 3); 459 *to++ = type; 460 *to++ = len + 3; 461 *to++ = feat; 462 463 if (len) 464 memcpy(to, val, len); 465 466 dccp_pr_debug("%s(%s (%d), ...), length %d\n", 467 dccp_feat_typename(type), 468 dccp_feat_name(feat), feat, len); 469 return 0; 470} 471 472static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb) 473{ 474 struct dccp_sock *dp = dccp_sk(sk); 475 struct dccp_minisock *dmsk = dccp_msk(sk); 476 struct dccp_opt_pend *opt, *next; 477 int change = 0; 478 479 /* confirm any options [NN opts] */ 480 list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) { 481 dccp_insert_feat_opt(skb, opt->dccpop_type, 482 opt->dccpop_feat, opt->dccpop_val, 483 opt->dccpop_len); 484 /* fear empty confirms */ 485 if (opt->dccpop_val) 486 kfree(opt->dccpop_val); 487 kfree(opt); 488 } 489 INIT_LIST_HEAD(&dmsk->dccpms_conf); 490 491 /* see which features we need to send */ 492 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { 493 /* see if we need to send any confirm */ 494 if (opt->dccpop_sc) { 495 dccp_insert_feat_opt(skb, opt->dccpop_type + 1, 496 opt->dccpop_feat, 497 opt->dccpop_sc->dccpoc_val, 498 opt->dccpop_sc->dccpoc_len); 499 500 BUG_ON(!opt->dccpop_sc->dccpoc_val); 501 kfree(opt->dccpop_sc->dccpoc_val); 502 kfree(opt->dccpop_sc); 503 opt->dccpop_sc = NULL; 504 } 505 506 /* any option not confirmed, re-send it */ 507 if (!opt->dccpop_conf) { 508 dccp_insert_feat_opt(skb, opt->dccpop_type, 509 opt->dccpop_feat, opt->dccpop_val, 510 opt->dccpop_len); 511 change++; 512 } 513 } 514 515 /* Retransmit timer. 516 * If this is the master listening sock, we don't set a timer on it. It 517 * should be fine because if the dude doesn't receive our RESPONSE 518 * [which will contain the CHANGE] he will send another REQUEST which 519 * will "retrnasmit" the change. 520 */ 521 if (change && dp->dccps_role != DCCP_ROLE_LISTEN) { 522 dccp_pr_debug("reset feat negotiation timer %p\n", sk); 523 524 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, 525 inet_csk(sk)->icsk_rto, DCCP_RTO_MAX); 526 } 527 528 return 0; 529} 530 531int dccp_insert_options(struct sock *sk, struct sk_buff *skb) 532{ 533 struct dccp_sock *dp = dccp_sk(sk); 534 struct dccp_minisock *dmsk = dccp_msk(sk); 535 536 DCCP_SKB_CB(skb)->dccpd_opt_len = 0; 537 538 if (dmsk->dccpms_send_ndp_count && 539 dccp_insert_option_ndp(sk, skb)) 540 return -1; 541 542 if (!dccp_packet_without_ack(skb)) { 543 if (dmsk->dccpms_send_ack_vector && 544 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) && 545 dccp_insert_option_ackvec(sk, skb)) 546 return -1; 547 548 if (dp->dccps_timestamp_echo != 0 && 549 dccp_insert_option_timestamp_echo(sk, skb)) 550 return -1; 551 } 552 553 if (dp->dccps_hc_rx_insert_options) { 554 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb)) 555 return -1; 556 dp->dccps_hc_rx_insert_options = 0; 557 } 558 559 /* Feature negotiation */ 560 /* Data packets can't do feat negotiation */ 561 if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA && 562 DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATAACK && 563 dccp_insert_options_feat(sk, skb)) 564 return -1; 565 566 /* 567 * Obtain RTT sample from Request/Response exchange. 568 * This is currently used in CCID 3 initialisation. 569 */ 570 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST && 571 dccp_insert_option_timestamp(sk, skb)) 572 return -1; 573 574 575 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