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 EXPORT_SYMBOL_GPL(dccp_feat_default_sequence_window); 33 34 void dccp_minisock_init(struct dccp_minisock *dmsk) 35 { 36 dmsk->dccpms_sequence_window = dccp_feat_default_sequence_window; 37 dmsk->dccpms_rx_ccid = dccp_feat_default_rx_ccid; 38 dmsk->dccpms_tx_ccid = dccp_feat_default_tx_ccid; 39 dmsk->dccpms_ack_ratio = dccp_feat_default_ack_ratio; 40 dmsk->dccpms_send_ack_vector = dccp_feat_default_send_ack_vector; 41 dmsk->dccpms_send_ndp_count = dccp_feat_default_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 #ifdef CONFIG_IP_DCCP_DEBUG 64 const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ? 65 "CLIENT rx opt: " : "server rx opt: "; 66 #endif 67 const struct dccp_hdr *dh = dccp_hdr(skb); 68 const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type; 69 unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb); 70 unsigned char *opt_ptr = options; 71 const unsigned char *opt_end = (unsigned char *)dh + 72 (dh->dccph_doff * 4); 73 struct dccp_options_received *opt_recv = &dp->dccps_options_received; 74 unsigned char opt, len; 75 unsigned char *value; 76 u32 elapsed_time; 77 int rc; 78 int mandatory = 0; 79 80 memset(opt_recv, 0, sizeof(*opt_recv)); 81 82 opt = len = 0; 83 while (opt_ptr != opt_end) { 84 opt = *opt_ptr++; 85 len = 0; 86 value = NULL; 87 88 /* Check if this isn't a single byte option */ 89 if (opt > DCCPO_MAX_RESERVED) { 90 if (opt_ptr == opt_end) 91 goto out_invalid_option; 92 93 len = *opt_ptr++; 94 if (len < 3) 95 goto out_invalid_option; 96 /* 97 * Remove the type and len fields, leaving 98 * just the value size 99 */ 100 len -= 2; 101 value = opt_ptr; 102 opt_ptr += len; 103 104 if (opt_ptr > opt_end) 105 goto out_invalid_option; 106 } 107 108 switch (opt) { 109 case DCCPO_PADDING: 110 break; 111 case DCCPO_MANDATORY: 112 if (mandatory) 113 goto out_invalid_option; 114 if (pkt_type != DCCP_PKT_DATA) 115 mandatory = 1; 116 break; 117 case DCCPO_NDP_COUNT: 118 if (len > 3) 119 goto out_invalid_option; 120 121 opt_recv->dccpor_ndp = dccp_decode_value_var(value, len); 122 dccp_pr_debug("%sNDP count=%d\n", debug_prefix, 123 opt_recv->dccpor_ndp); 124 break; 125 case DCCPO_CHANGE_L: 126 /* fall through */ 127 case DCCPO_CHANGE_R: 128 if (len < 2) 129 goto out_invalid_option; 130 rc = dccp_feat_change_recv(sk, opt, *value, value + 1, 131 len - 1); 132 /* 133 * When there is a change error, change_recv is 134 * responsible for dealing with it. i.e. reply with an 135 * empty confirm. 136 * If the change was mandatory, then we need to die. 137 */ 138 if (rc && mandatory) 139 goto out_invalid_option; 140 break; 141 case DCCPO_CONFIRM_L: 142 /* fall through */ 143 case DCCPO_CONFIRM_R: 144 if (len < 2) 145 goto out_invalid_option; 146 if (dccp_feat_confirm_recv(sk, opt, *value, 147 value + 1, len - 1)) 148 goto out_invalid_option; 149 break; 150 case DCCPO_ACK_VECTOR_0: 151 case DCCPO_ACK_VECTOR_1: 152 if (pkt_type == DCCP_PKT_DATA) 153 break; 154 155 if (dccp_msk(sk)->dccpms_send_ack_vector && 156 dccp_ackvec_parse(sk, skb, opt, value, len)) 157 goto out_invalid_option; 158 break; 159 case DCCPO_TIMESTAMP: 160 if (len != 4) 161 goto out_invalid_option; 162 163 opt_recv->dccpor_timestamp = ntohl(*(__be32 *)value); 164 165 dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp; 166 dccp_timestamp(sk, &dp->dccps_timestamp_time); 167 168 dccp_pr_debug("%sTIMESTAMP=%u, ackno=%llu\n", 169 debug_prefix, opt_recv->dccpor_timestamp, 170 (unsigned long long) 171 DCCP_SKB_CB(skb)->dccpd_ack_seq); 172 break; 173 case DCCPO_TIMESTAMP_ECHO: 174 if (len != 4 && len != 6 && len != 8) 175 goto out_invalid_option; 176 177 opt_recv->dccpor_timestamp_echo = ntohl(*(__be32 *)value); 178 179 dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, ackno=%llu, ", 180 debug_prefix, 181 opt_recv->dccpor_timestamp_echo, 182 len + 2, 183 (unsigned long long) 184 DCCP_SKB_CB(skb)->dccpd_ack_seq); 185 186 187 if (len == 4) 188 break; 189 190 if (len == 6) 191 elapsed_time = ntohs(*(__be16 *)(value + 4)); 192 else 193 elapsed_time = ntohl(*(__be32 *)(value + 4)); 194 195 /* Give precedence to the biggest ELAPSED_TIME */ 196 if (elapsed_time > opt_recv->dccpor_elapsed_time) 197 opt_recv->dccpor_elapsed_time = elapsed_time; 198 break; 199 case DCCPO_ELAPSED_TIME: 200 if (len != 2 && len != 4) 201 goto out_invalid_option; 202 203 if (pkt_type == DCCP_PKT_DATA) 204 continue; 205 206 if (len == 2) 207 elapsed_time = ntohs(*(__be16 *)value); 208 else 209 elapsed_time = ntohl(*(__be32 *)value); 210 211 if (elapsed_time > opt_recv->dccpor_elapsed_time) 212 opt_recv->dccpor_elapsed_time = elapsed_time; 213 214 dccp_pr_debug("%sELAPSED_TIME=%d\n", debug_prefix, 215 elapsed_time); 216 break; 217 /* 218 * From draft-ietf-dccp-spec-11.txt: 219 * 220 * Option numbers 128 through 191 are for 221 * options sent from the HC-Sender to the 222 * HC-Receiver; option numbers 192 through 255 223 * are for options sent from the HC-Receiver to 224 * the HC-Sender. 225 */ 226 case 128 ... 191: { 227 const u16 idx = value - options; 228 229 if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk, 230 opt, len, idx, 231 value) != 0) 232 goto out_invalid_option; 233 } 234 break; 235 case 192 ... 255: { 236 const u16 idx = value - options; 237 238 if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk, 239 opt, len, idx, 240 value) != 0) 241 goto out_invalid_option; 242 } 243 break; 244 default: 245 pr_info("DCCP(%p): option %d(len=%d) not " 246 "implemented, ignoring\n", 247 sk, opt, len); 248 break; 249 } 250 251 if (opt != DCCPO_MANDATORY) 252 mandatory = 0; 253 } 254 255 /* mandatory was the last byte in option list -> reset connection */ 256 if (mandatory) 257 goto out_invalid_option; 258 259 return 0; 260 261 out_invalid_option: 262 DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT); 263 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR; 264 pr_info("DCCP(%p): invalid option %d, len=%d\n", sk, opt, len); 265 return -1; 266 } 267 268 EXPORT_SYMBOL_GPL(dccp_parse_options); 269 270 static void dccp_encode_value_var(const u32 value, unsigned char *to, 271 const unsigned int len) 272 { 273 if (len > 3) 274 *to++ = (value & 0xFF000000) >> 24; 275 if (len > 2) 276 *to++ = (value & 0xFF0000) >> 16; 277 if (len > 1) 278 *to++ = (value & 0xFF00) >> 8; 279 if (len > 0) 280 *to++ = (value & 0xFF); 281 } 282 283 static inline int dccp_ndp_len(const int ndp) 284 { 285 return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3; 286 } 287 288 int dccp_insert_option(struct sock *sk, struct sk_buff *skb, 289 const unsigned char option, 290 const void *value, const unsigned char len) 291 { 292 unsigned char *to; 293 294 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN) 295 return -1; 296 297 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2; 298 299 to = skb_push(skb, len + 2); 300 *to++ = option; 301 *to++ = len + 2; 302 303 memcpy(to, value, len); 304 return 0; 305 } 306 307 EXPORT_SYMBOL_GPL(dccp_insert_option); 308 309 static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb) 310 { 311 struct dccp_sock *dp = dccp_sk(sk); 312 int ndp = dp->dccps_ndp_count; 313 314 if (dccp_non_data_packet(skb)) 315 ++dp->dccps_ndp_count; 316 else 317 dp->dccps_ndp_count = 0; 318 319 if (ndp > 0) { 320 unsigned char *ptr; 321 const int ndp_len = dccp_ndp_len(ndp); 322 const int len = ndp_len + 2; 323 324 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) 325 return -1; 326 327 DCCP_SKB_CB(skb)->dccpd_opt_len += len; 328 329 ptr = skb_push(skb, len); 330 *ptr++ = DCCPO_NDP_COUNT; 331 *ptr++ = len; 332 dccp_encode_value_var(ndp, ptr, ndp_len); 333 } 334 335 return 0; 336 } 337 338 static inline int dccp_elapsed_time_len(const u32 elapsed_time) 339 { 340 return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4; 341 } 342 343 int dccp_insert_option_elapsed_time(struct sock *sk, struct sk_buff *skb, 344 u32 elapsed_time) 345 { 346 const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time); 347 const int len = 2 + elapsed_time_len; 348 unsigned char *to; 349 350 if (elapsed_time_len == 0) 351 return 0; 352 353 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) 354 return -1; 355 356 DCCP_SKB_CB(skb)->dccpd_opt_len += len; 357 358 to = skb_push(skb, len); 359 *to++ = DCCPO_ELAPSED_TIME; 360 *to++ = len; 361 362 if (elapsed_time_len == 2) { 363 const __be16 var16 = htons((u16)elapsed_time); 364 memcpy(to, &var16, 2); 365 } else { 366 const __be32 var32 = htonl(elapsed_time); 367 memcpy(to, &var32, 4); 368 } 369 370 return 0; 371 } 372 373 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time); 374 375 void dccp_timestamp(const struct sock *sk, struct timeval *tv) 376 { 377 const struct dccp_sock *dp = dccp_sk(sk); 378 379 do_gettimeofday(tv); 380 tv->tv_sec -= dp->dccps_epoch.tv_sec; 381 tv->tv_usec -= dp->dccps_epoch.tv_usec; 382 383 while (tv->tv_usec < 0) { 384 tv->tv_sec--; 385 tv->tv_usec += USEC_PER_SEC; 386 } 387 } 388 389 EXPORT_SYMBOL_GPL(dccp_timestamp); 390 391 int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb) 392 { 393 struct timeval tv; 394 __be32 now; 395 396 dccp_timestamp(sk, &tv); 397 now = htonl(timeval_usecs(&tv) / 10); 398 /* yes this will overflow but that is the point as we want a 399 * 10 usec 32 bit timer which mean it wraps every 11.9 hours */ 400 401 return dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now)); 402 } 403 404 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp); 405 406 static int dccp_insert_option_timestamp_echo(struct sock *sk, 407 struct sk_buff *skb) 408 { 409 struct dccp_sock *dp = dccp_sk(sk); 410 struct timeval now; 411 __be32 tstamp_echo; 412 u32 elapsed_time; 413 int len, elapsed_time_len; 414 unsigned char *to; 415 416 dccp_timestamp(sk, &now); 417 elapsed_time = timeval_delta(&now, &dp->dccps_timestamp_time) / 10; 418 elapsed_time_len = dccp_elapsed_time_len(elapsed_time); 419 len = 6 + elapsed_time_len; 420 421 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) 422 return -1; 423 424 DCCP_SKB_CB(skb)->dccpd_opt_len += len; 425 426 to = skb_push(skb, len); 427 *to++ = DCCPO_TIMESTAMP_ECHO; 428 *to++ = len; 429 430 tstamp_echo = htonl(dp->dccps_timestamp_echo); 431 memcpy(to, &tstamp_echo, 4); 432 to += 4; 433 434 if (elapsed_time_len == 2) { 435 const __be16 var16 = htons((u16)elapsed_time); 436 memcpy(to, &var16, 2); 437 } else if (elapsed_time_len == 4) { 438 const __be32 var32 = htonl(elapsed_time); 439 memcpy(to, &var32, 4); 440 } 441 442 dp->dccps_timestamp_echo = 0; 443 dp->dccps_timestamp_time.tv_sec = 0; 444 dp->dccps_timestamp_time.tv_usec = 0; 445 return 0; 446 } 447 448 static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat, 449 u8 *val, u8 len) 450 { 451 u8 *to; 452 453 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 3 > DCCP_MAX_OPT_LEN) { 454 LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small" 455 " to insert feature %d option!\n", feat); 456 return -1; 457 } 458 459 DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3; 460 461 to = skb_push(skb, len + 3); 462 *to++ = type; 463 *to++ = len + 3; 464 *to++ = feat; 465 466 if (len) 467 memcpy(to, val, len); 468 dccp_pr_debug("option %d feat %d len %d\n", type, feat, len); 469 470 return 0; 471 } 472 473 static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb) 474 { 475 struct dccp_sock *dp = dccp_sk(sk); 476 struct dccp_minisock *dmsk = dccp_msk(sk); 477 struct dccp_opt_pend *opt, *next; 478 int change = 0; 479 480 /* confirm any options [NN opts] */ 481 list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) { 482 dccp_insert_feat_opt(skb, opt->dccpop_type, 483 opt->dccpop_feat, opt->dccpop_val, 484 opt->dccpop_len); 485 /* fear empty confirms */ 486 if (opt->dccpop_val) 487 kfree(opt->dccpop_val); 488 kfree(opt); 489 } 490 INIT_LIST_HEAD(&dmsk->dccpms_conf); 491 492 /* see which features we need to send */ 493 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { 494 /* see if we need to send any confirm */ 495 if (opt->dccpop_sc) { 496 dccp_insert_feat_opt(skb, opt->dccpop_type + 1, 497 opt->dccpop_feat, 498 opt->dccpop_sc->dccpoc_val, 499 opt->dccpop_sc->dccpoc_len); 500 501 BUG_ON(!opt->dccpop_sc->dccpoc_val); 502 kfree(opt->dccpop_sc->dccpoc_val); 503 kfree(opt->dccpop_sc); 504 opt->dccpop_sc = NULL; 505 } 506 507 /* any option not confirmed, re-send it */ 508 if (!opt->dccpop_conf) { 509 dccp_insert_feat_opt(skb, opt->dccpop_type, 510 opt->dccpop_feat, opt->dccpop_val, 511 opt->dccpop_len); 512 change++; 513 } 514 } 515 516 /* Retransmit timer. 517 * If this is the master listening sock, we don't set a timer on it. It 518 * should be fine because if the dude doesn't receive our RESPONSE 519 * [which will contain the CHANGE] he will send another REQUEST which 520 * will "retrnasmit" the change. 521 */ 522 if (change && dp->dccps_role != DCCP_ROLE_LISTEN) { 523 dccp_pr_debug("reset feat negotiation timer %p\n", sk); 524 525 /* XXX don't reset the timer on re-transmissions. I.e. reset it 526 * only when sending new stuff i guess. Currently the timer 527 * never backs off because on re-transmission it just resets it! 528 */ 529 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, 530 inet_csk(sk)->icsk_rto, DCCP_RTO_MAX); 531 } 532 533 return 0; 534 } 535 536 int dccp_insert_options(struct sock *sk, struct sk_buff *skb) 537 { 538 struct dccp_sock *dp = dccp_sk(sk); 539 struct dccp_minisock *dmsk = dccp_msk(sk); 540 541 DCCP_SKB_CB(skb)->dccpd_opt_len = 0; 542 543 if (dmsk->dccpms_send_ndp_count && 544 dccp_insert_option_ndp(sk, skb)) 545 return -1; 546 547 if (!dccp_packet_without_ack(skb)) { 548 if (dmsk->dccpms_send_ack_vector && 549 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) && 550 dccp_insert_option_ackvec(sk, skb)) 551 return -1; 552 553 if (dp->dccps_timestamp_echo != 0 && 554 dccp_insert_option_timestamp_echo(sk, skb)) 555 return -1; 556 } 557 558 if (dp->dccps_hc_rx_insert_options) { 559 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb)) 560 return -1; 561 dp->dccps_hc_rx_insert_options = 0; 562 } 563 if (dp->dccps_hc_tx_insert_options) { 564 if (ccid_hc_tx_insert_options(dp->dccps_hc_tx_ccid, sk, skb)) 565 return -1; 566 dp->dccps_hc_tx_insert_options = 0; 567 } 568 569 /* Feature negotiation */ 570 /* Data packets can't do feat negotiation */ 571 if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA && 572 DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATAACK && 573 dccp_insert_options_feat(sk, skb)) 574 return -1; 575 576 /* XXX: insert other options when appropriate */ 577 578 if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) { 579 /* The length of all options has to be a multiple of 4 */ 580 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4; 581 582 if (padding != 0) { 583 padding = 4 - padding; 584 memset(skb_push(skb, padding), 0, padding); 585 DCCP_SKB_CB(skb)->dccpd_opt_len += padding; 586 } 587 } 588 589 return 0; 590 } 591