1 // SPDX-License-Identifier: GPL-2.0 2 /* Multipath TCP 3 * 4 * Copyright (c) 2017 - 2019, Intel Corporation. 5 */ 6 7 #define pr_fmt(fmt) "MPTCP: " fmt 8 9 #include <linux/kernel.h> 10 #include <crypto/sha2.h> 11 #include <net/tcp.h> 12 #include <net/mptcp.h> 13 #include "protocol.h" 14 #include "mib.h" 15 16 #include <trace/events/mptcp.h> 17 18 static bool mptcp_cap_flag_sha256(u8 flags) 19 { 20 return (flags & MPTCP_CAP_FLAG_MASK) == MPTCP_CAP_HMAC_SHA256; 21 } 22 23 static void mptcp_parse_option(const struct sk_buff *skb, 24 const unsigned char *ptr, int opsize, 25 struct mptcp_options_received *mp_opt) 26 { 27 u8 subtype = *ptr >> 4; 28 int expected_opsize; 29 u8 version; 30 u8 flags; 31 u8 i; 32 33 switch (subtype) { 34 case MPTCPOPT_MP_CAPABLE: 35 /* strict size checking */ 36 if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) { 37 if (skb->len > tcp_hdr(skb)->doff << 2) 38 expected_opsize = TCPOLEN_MPTCP_MPC_ACK_DATA; 39 else 40 expected_opsize = TCPOLEN_MPTCP_MPC_ACK; 41 } else { 42 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_ACK) 43 expected_opsize = TCPOLEN_MPTCP_MPC_SYNACK; 44 else 45 expected_opsize = TCPOLEN_MPTCP_MPC_SYN; 46 } 47 if (opsize != expected_opsize) 48 break; 49 50 /* try to be gentle vs future versions on the initial syn */ 51 version = *ptr++ & MPTCP_VERSION_MASK; 52 if (opsize != TCPOLEN_MPTCP_MPC_SYN) { 53 if (version != MPTCP_SUPPORTED_VERSION) 54 break; 55 } else if (version < MPTCP_SUPPORTED_VERSION) { 56 break; 57 } 58 59 flags = *ptr++; 60 if (!mptcp_cap_flag_sha256(flags) || 61 (flags & MPTCP_CAP_EXTENSIBILITY)) 62 break; 63 64 /* RFC 6824, Section 3.1: 65 * "For the Checksum Required bit (labeled "A"), if either 66 * host requires the use of checksums, checksums MUST be used. 67 * In other words, the only way for checksums not to be used 68 * is if both hosts in their SYNs set A=0." 69 * 70 * Section 3.3.0: 71 * "If a checksum is not present when its use has been 72 * negotiated, the receiver MUST close the subflow with a RST as 73 * it is considered broken." 74 * 75 * We don't implement DSS checksum - fall back to TCP. 76 */ 77 if (flags & MPTCP_CAP_CHECKSUM_REQD) 78 break; 79 80 mp_opt->mp_capable = 1; 81 if (opsize >= TCPOLEN_MPTCP_MPC_SYNACK) { 82 mp_opt->sndr_key = get_unaligned_be64(ptr); 83 ptr += 8; 84 } 85 if (opsize >= TCPOLEN_MPTCP_MPC_ACK) { 86 mp_opt->rcvr_key = get_unaligned_be64(ptr); 87 ptr += 8; 88 } 89 if (opsize == TCPOLEN_MPTCP_MPC_ACK_DATA) { 90 /* Section 3.1.: 91 * "the data parameters in a MP_CAPABLE are semantically 92 * equivalent to those in a DSS option and can be used 93 * interchangeably." 94 */ 95 mp_opt->dss = 1; 96 mp_opt->use_map = 1; 97 mp_opt->mpc_map = 1; 98 mp_opt->data_len = get_unaligned_be16(ptr); 99 ptr += 2; 100 } 101 pr_debug("MP_CAPABLE version=%x, flags=%x, optlen=%d sndr=%llu, rcvr=%llu len=%d", 102 version, flags, opsize, mp_opt->sndr_key, 103 mp_opt->rcvr_key, mp_opt->data_len); 104 break; 105 106 case MPTCPOPT_MP_JOIN: 107 mp_opt->mp_join = 1; 108 if (opsize == TCPOLEN_MPTCP_MPJ_SYN) { 109 mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP; 110 mp_opt->join_id = *ptr++; 111 mp_opt->token = get_unaligned_be32(ptr); 112 ptr += 4; 113 mp_opt->nonce = get_unaligned_be32(ptr); 114 ptr += 4; 115 pr_debug("MP_JOIN bkup=%u, id=%u, token=%u, nonce=%u", 116 mp_opt->backup, mp_opt->join_id, 117 mp_opt->token, mp_opt->nonce); 118 } else if (opsize == TCPOLEN_MPTCP_MPJ_SYNACK) { 119 mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP; 120 mp_opt->join_id = *ptr++; 121 mp_opt->thmac = get_unaligned_be64(ptr); 122 ptr += 8; 123 mp_opt->nonce = get_unaligned_be32(ptr); 124 ptr += 4; 125 pr_debug("MP_JOIN bkup=%u, id=%u, thmac=%llu, nonce=%u", 126 mp_opt->backup, mp_opt->join_id, 127 mp_opt->thmac, mp_opt->nonce); 128 } else if (opsize == TCPOLEN_MPTCP_MPJ_ACK) { 129 ptr += 2; 130 memcpy(mp_opt->hmac, ptr, MPTCPOPT_HMAC_LEN); 131 pr_debug("MP_JOIN hmac"); 132 } else { 133 mp_opt->mp_join = 0; 134 } 135 break; 136 137 case MPTCPOPT_DSS: 138 pr_debug("DSS"); 139 ptr++; 140 141 /* we must clear 'mpc_map' be able to detect MP_CAPABLE 142 * map vs DSS map in mptcp_incoming_options(), and reconstruct 143 * map info accordingly 144 */ 145 mp_opt->mpc_map = 0; 146 flags = (*ptr++) & MPTCP_DSS_FLAG_MASK; 147 mp_opt->data_fin = (flags & MPTCP_DSS_DATA_FIN) != 0; 148 mp_opt->dsn64 = (flags & MPTCP_DSS_DSN64) != 0; 149 mp_opt->use_map = (flags & MPTCP_DSS_HAS_MAP) != 0; 150 mp_opt->ack64 = (flags & MPTCP_DSS_ACK64) != 0; 151 mp_opt->use_ack = (flags & MPTCP_DSS_HAS_ACK); 152 153 pr_debug("data_fin=%d dsn64=%d use_map=%d ack64=%d use_ack=%d", 154 mp_opt->data_fin, mp_opt->dsn64, 155 mp_opt->use_map, mp_opt->ack64, 156 mp_opt->use_ack); 157 158 expected_opsize = TCPOLEN_MPTCP_DSS_BASE; 159 160 if (mp_opt->use_ack) { 161 if (mp_opt->ack64) 162 expected_opsize += TCPOLEN_MPTCP_DSS_ACK64; 163 else 164 expected_opsize += TCPOLEN_MPTCP_DSS_ACK32; 165 } 166 167 if (mp_opt->use_map) { 168 if (mp_opt->dsn64) 169 expected_opsize += TCPOLEN_MPTCP_DSS_MAP64; 170 else 171 expected_opsize += TCPOLEN_MPTCP_DSS_MAP32; 172 } 173 174 /* RFC 6824, Section 3.3: 175 * If a checksum is present, but its use had 176 * not been negotiated in the MP_CAPABLE handshake, 177 * the checksum field MUST be ignored. 178 */ 179 if (opsize != expected_opsize && 180 opsize != expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM) 181 break; 182 183 mp_opt->dss = 1; 184 185 if (mp_opt->use_ack) { 186 if (mp_opt->ack64) { 187 mp_opt->data_ack = get_unaligned_be64(ptr); 188 ptr += 8; 189 } else { 190 mp_opt->data_ack = get_unaligned_be32(ptr); 191 ptr += 4; 192 } 193 194 pr_debug("data_ack=%llu", mp_opt->data_ack); 195 } 196 197 if (mp_opt->use_map) { 198 if (mp_opt->dsn64) { 199 mp_opt->data_seq = get_unaligned_be64(ptr); 200 ptr += 8; 201 } else { 202 mp_opt->data_seq = get_unaligned_be32(ptr); 203 ptr += 4; 204 } 205 206 mp_opt->subflow_seq = get_unaligned_be32(ptr); 207 ptr += 4; 208 209 mp_opt->data_len = get_unaligned_be16(ptr); 210 ptr += 2; 211 212 pr_debug("data_seq=%llu subflow_seq=%u data_len=%u", 213 mp_opt->data_seq, mp_opt->subflow_seq, 214 mp_opt->data_len); 215 } 216 217 break; 218 219 case MPTCPOPT_ADD_ADDR: 220 mp_opt->echo = (*ptr++) & MPTCP_ADDR_ECHO; 221 if (!mp_opt->echo) { 222 if (opsize == TCPOLEN_MPTCP_ADD_ADDR || 223 opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT) 224 mp_opt->addr.family = AF_INET; 225 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 226 else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6 || 227 opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT) 228 mp_opt->addr.family = AF_INET6; 229 #endif 230 else 231 break; 232 } else { 233 if (opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE || 234 opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) 235 mp_opt->addr.family = AF_INET; 236 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 237 else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE || 238 opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) 239 mp_opt->addr.family = AF_INET6; 240 #endif 241 else 242 break; 243 } 244 245 mp_opt->add_addr = 1; 246 mp_opt->addr.id = *ptr++; 247 if (mp_opt->addr.family == AF_INET) { 248 memcpy((u8 *)&mp_opt->addr.addr.s_addr, (u8 *)ptr, 4); 249 ptr += 4; 250 if (opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT || 251 opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) { 252 mp_opt->addr.port = htons(get_unaligned_be16(ptr)); 253 ptr += 2; 254 } 255 } 256 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 257 else { 258 memcpy(mp_opt->addr.addr6.s6_addr, (u8 *)ptr, 16); 259 ptr += 16; 260 if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT || 261 opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) { 262 mp_opt->addr.port = htons(get_unaligned_be16(ptr)); 263 ptr += 2; 264 } 265 } 266 #endif 267 if (!mp_opt->echo) { 268 mp_opt->ahmac = get_unaligned_be64(ptr); 269 ptr += 8; 270 } 271 pr_debug("ADD_ADDR%s: id=%d, ahmac=%llu, echo=%d, port=%d", 272 (mp_opt->addr.family == AF_INET6) ? "6" : "", 273 mp_opt->addr.id, mp_opt->ahmac, mp_opt->echo, ntohs(mp_opt->addr.port)); 274 break; 275 276 case MPTCPOPT_RM_ADDR: 277 if (opsize < TCPOLEN_MPTCP_RM_ADDR_BASE + 1 || 278 opsize > TCPOLEN_MPTCP_RM_ADDR_BASE + MPTCP_RM_IDS_MAX) 279 break; 280 281 ptr++; 282 283 mp_opt->rm_addr = 1; 284 mp_opt->rm_list.nr = opsize - TCPOLEN_MPTCP_RM_ADDR_BASE; 285 for (i = 0; i < mp_opt->rm_list.nr; i++) 286 mp_opt->rm_list.ids[i] = *ptr++; 287 pr_debug("RM_ADDR: rm_list_nr=%d", mp_opt->rm_list.nr); 288 break; 289 290 case MPTCPOPT_MP_PRIO: 291 if (opsize != TCPOLEN_MPTCP_PRIO) 292 break; 293 294 mp_opt->mp_prio = 1; 295 mp_opt->backup = *ptr++ & MPTCP_PRIO_BKUP; 296 pr_debug("MP_PRIO: prio=%d", mp_opt->backup); 297 break; 298 299 case MPTCPOPT_MP_FASTCLOSE: 300 if (opsize != TCPOLEN_MPTCP_FASTCLOSE) 301 break; 302 303 ptr += 2; 304 mp_opt->rcvr_key = get_unaligned_be64(ptr); 305 ptr += 8; 306 mp_opt->fastclose = 1; 307 break; 308 309 case MPTCPOPT_RST: 310 if (opsize != TCPOLEN_MPTCP_RST) 311 break; 312 313 if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) 314 break; 315 mp_opt->reset = 1; 316 flags = *ptr++; 317 mp_opt->reset_transient = flags & MPTCP_RST_TRANSIENT; 318 mp_opt->reset_reason = *ptr; 319 break; 320 321 default: 322 break; 323 } 324 } 325 326 void mptcp_get_options(const struct sk_buff *skb, 327 struct mptcp_options_received *mp_opt) 328 { 329 const struct tcphdr *th = tcp_hdr(skb); 330 const unsigned char *ptr; 331 int length; 332 333 /* initialize option status */ 334 mp_opt->mp_capable = 0; 335 mp_opt->mp_join = 0; 336 mp_opt->add_addr = 0; 337 mp_opt->ahmac = 0; 338 mp_opt->fastclose = 0; 339 mp_opt->addr.port = 0; 340 mp_opt->rm_addr = 0; 341 mp_opt->dss = 0; 342 mp_opt->mp_prio = 0; 343 mp_opt->reset = 0; 344 345 length = (th->doff * 4) - sizeof(struct tcphdr); 346 ptr = (const unsigned char *)(th + 1); 347 348 while (length > 0) { 349 int opcode = *ptr++; 350 int opsize; 351 352 switch (opcode) { 353 case TCPOPT_EOL: 354 return; 355 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */ 356 length--; 357 continue; 358 default: 359 opsize = *ptr++; 360 if (opsize < 2) /* "silly options" */ 361 return; 362 if (opsize > length) 363 return; /* don't parse partial options */ 364 if (opcode == TCPOPT_MPTCP) 365 mptcp_parse_option(skb, ptr, opsize, mp_opt); 366 ptr += opsize - 2; 367 length -= opsize; 368 } 369 } 370 } 371 372 bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb, 373 unsigned int *size, struct mptcp_out_options *opts) 374 { 375 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 376 377 /* we will use snd_isn to detect first pkt [re]transmission 378 * in mptcp_established_options_mp() 379 */ 380 subflow->snd_isn = TCP_SKB_CB(skb)->end_seq; 381 if (subflow->request_mptcp) { 382 opts->suboptions = OPTION_MPTCP_MPC_SYN; 383 *size = TCPOLEN_MPTCP_MPC_SYN; 384 return true; 385 } else if (subflow->request_join) { 386 pr_debug("remote_token=%u, nonce=%u", subflow->remote_token, 387 subflow->local_nonce); 388 opts->suboptions = OPTION_MPTCP_MPJ_SYN; 389 opts->join_id = subflow->local_id; 390 opts->token = subflow->remote_token; 391 opts->nonce = subflow->local_nonce; 392 opts->backup = subflow->request_bkup; 393 *size = TCPOLEN_MPTCP_MPJ_SYN; 394 return true; 395 } 396 return false; 397 } 398 399 /* MP_JOIN client subflow must wait for 4th ack before sending any data: 400 * TCP can't schedule delack timer before the subflow is fully established. 401 * MPTCP uses the delack timer to do 3rd ack retransmissions 402 */ 403 static void schedule_3rdack_retransmission(struct sock *sk) 404 { 405 struct inet_connection_sock *icsk = inet_csk(sk); 406 struct tcp_sock *tp = tcp_sk(sk); 407 unsigned long timeout; 408 409 /* reschedule with a timeout above RTT, as we must look only for drop */ 410 if (tp->srtt_us) 411 timeout = tp->srtt_us << 1; 412 else 413 timeout = TCP_TIMEOUT_INIT; 414 415 WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER); 416 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; 417 icsk->icsk_ack.timeout = timeout; 418 sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout); 419 } 420 421 static void clear_3rdack_retransmission(struct sock *sk) 422 { 423 struct inet_connection_sock *icsk = inet_csk(sk); 424 425 sk_stop_timer(sk, &icsk->icsk_delack_timer); 426 icsk->icsk_ack.timeout = 0; 427 icsk->icsk_ack.ato = 0; 428 icsk->icsk_ack.pending &= ~(ICSK_ACK_SCHED | ICSK_ACK_TIMER); 429 } 430 431 static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb, 432 bool snd_data_fin_enable, 433 unsigned int *size, 434 unsigned int remaining, 435 struct mptcp_out_options *opts) 436 { 437 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 438 struct mptcp_ext *mpext; 439 unsigned int data_len; 440 441 /* When skb is not available, we better over-estimate the emitted 442 * options len. A full DSS option (28 bytes) is longer than 443 * TCPOLEN_MPTCP_MPC_ACK_DATA(22) or TCPOLEN_MPTCP_MPJ_ACK(24), so 444 * tell the caller to defer the estimate to 445 * mptcp_established_options_dss(), which will reserve enough space. 446 */ 447 if (!skb) 448 return false; 449 450 /* MPC/MPJ needed only on 3rd ack packet, DATA_FIN and TCP shutdown take precedence */ 451 if (subflow->fully_established || snd_data_fin_enable || 452 subflow->snd_isn != TCP_SKB_CB(skb)->seq || 453 sk->sk_state != TCP_ESTABLISHED) 454 return false; 455 456 if (subflow->mp_capable) { 457 mpext = mptcp_get_ext(skb); 458 data_len = mpext ? mpext->data_len : 0; 459 460 /* we will check ext_copy.data_len in mptcp_write_options() to 461 * discriminate between TCPOLEN_MPTCP_MPC_ACK_DATA and 462 * TCPOLEN_MPTCP_MPC_ACK 463 */ 464 opts->ext_copy.data_len = data_len; 465 opts->suboptions = OPTION_MPTCP_MPC_ACK; 466 opts->sndr_key = subflow->local_key; 467 opts->rcvr_key = subflow->remote_key; 468 469 /* Section 3.1. 470 * The MP_CAPABLE option is carried on the SYN, SYN/ACK, and ACK 471 * packets that start the first subflow of an MPTCP connection, 472 * as well as the first packet that carries data 473 */ 474 if (data_len > 0) 475 *size = ALIGN(TCPOLEN_MPTCP_MPC_ACK_DATA, 4); 476 else 477 *size = TCPOLEN_MPTCP_MPC_ACK; 478 479 pr_debug("subflow=%p, local_key=%llu, remote_key=%llu map_len=%d", 480 subflow, subflow->local_key, subflow->remote_key, 481 data_len); 482 483 return true; 484 } else if (subflow->mp_join) { 485 opts->suboptions = OPTION_MPTCP_MPJ_ACK; 486 memcpy(opts->hmac, subflow->hmac, MPTCPOPT_HMAC_LEN); 487 *size = TCPOLEN_MPTCP_MPJ_ACK; 488 pr_debug("subflow=%p", subflow); 489 490 schedule_3rdack_retransmission(sk); 491 return true; 492 } 493 return false; 494 } 495 496 static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow, 497 struct sk_buff *skb, struct mptcp_ext *ext) 498 { 499 /* The write_seq value has already been incremented, so the actual 500 * sequence number for the DATA_FIN is one less. 501 */ 502 u64 data_fin_tx_seq = READ_ONCE(mptcp_sk(subflow->conn)->write_seq) - 1; 503 504 if (!ext->use_map || !skb->len) { 505 /* RFC6824 requires a DSS mapping with specific values 506 * if DATA_FIN is set but no data payload is mapped 507 */ 508 ext->data_fin = 1; 509 ext->use_map = 1; 510 ext->dsn64 = 1; 511 ext->data_seq = data_fin_tx_seq; 512 ext->subflow_seq = 0; 513 ext->data_len = 1; 514 } else if (ext->data_seq + ext->data_len == data_fin_tx_seq) { 515 /* If there's an existing DSS mapping and it is the 516 * final mapping, DATA_FIN consumes 1 additional byte of 517 * mapping space. 518 */ 519 ext->data_fin = 1; 520 ext->data_len++; 521 } 522 } 523 524 static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb, 525 bool snd_data_fin_enable, 526 unsigned int *size, 527 unsigned int remaining, 528 struct mptcp_out_options *opts) 529 { 530 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 531 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 532 unsigned int dss_size = 0; 533 struct mptcp_ext *mpext; 534 unsigned int ack_size; 535 bool ret = false; 536 u64 ack_seq; 537 538 mpext = skb ? mptcp_get_ext(skb) : NULL; 539 540 if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) { 541 unsigned int map_size; 542 543 map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64; 544 545 remaining -= map_size; 546 dss_size = map_size; 547 if (mpext) 548 opts->ext_copy = *mpext; 549 550 if (skb && snd_data_fin_enable) 551 mptcp_write_data_fin(subflow, skb, &opts->ext_copy); 552 ret = true; 553 } 554 555 /* passive sockets msk will set the 'can_ack' after accept(), even 556 * if the first subflow may have the already the remote key handy 557 */ 558 opts->ext_copy.use_ack = 0; 559 if (!READ_ONCE(msk->can_ack)) { 560 *size = ALIGN(dss_size, 4); 561 return ret; 562 } 563 564 ack_seq = READ_ONCE(msk->ack_seq); 565 if (READ_ONCE(msk->use_64bit_ack)) { 566 ack_size = TCPOLEN_MPTCP_DSS_ACK64; 567 opts->ext_copy.data_ack = ack_seq; 568 opts->ext_copy.ack64 = 1; 569 } else { 570 ack_size = TCPOLEN_MPTCP_DSS_ACK32; 571 opts->ext_copy.data_ack32 = (uint32_t)ack_seq; 572 opts->ext_copy.ack64 = 0; 573 } 574 opts->ext_copy.use_ack = 1; 575 WRITE_ONCE(msk->old_wspace, __mptcp_space((struct sock *)msk)); 576 577 /* Add kind/length/subtype/flag overhead if mapping is not populated */ 578 if (dss_size == 0) 579 ack_size += TCPOLEN_MPTCP_DSS_BASE; 580 581 dss_size += ack_size; 582 583 *size = ALIGN(dss_size, 4); 584 return true; 585 } 586 587 static u64 add_addr_generate_hmac(u64 key1, u64 key2, 588 struct mptcp_addr_info *addr) 589 { 590 u16 port = ntohs(addr->port); 591 u8 hmac[SHA256_DIGEST_SIZE]; 592 u8 msg[19]; 593 int i = 0; 594 595 msg[i++] = addr->id; 596 if (addr->family == AF_INET) { 597 memcpy(&msg[i], &addr->addr.s_addr, 4); 598 i += 4; 599 } 600 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 601 else if (addr->family == AF_INET6) { 602 memcpy(&msg[i], &addr->addr6.s6_addr, 16); 603 i += 16; 604 } 605 #endif 606 msg[i++] = port >> 8; 607 msg[i++] = port & 0xFF; 608 609 mptcp_crypto_hmac_sha(key1, key2, msg, i, hmac); 610 611 return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]); 612 } 613 614 static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *skb, 615 unsigned int *size, 616 unsigned int remaining, 617 struct mptcp_out_options *opts) 618 { 619 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 620 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 621 bool drop_other_suboptions = false; 622 unsigned int opt_size = *size; 623 bool echo; 624 bool port; 625 int len; 626 627 if ((mptcp_pm_should_add_signal_ipv6(msk) || 628 mptcp_pm_should_add_signal_port(msk) || 629 mptcp_pm_should_add_signal_echo(msk)) && 630 skb && skb_is_tcp_pure_ack(skb)) { 631 pr_debug("drop other suboptions"); 632 opts->suboptions = 0; 633 opts->ext_copy.use_ack = 0; 634 opts->ext_copy.use_map = 0; 635 remaining += opt_size; 636 drop_other_suboptions = true; 637 } 638 639 if (!mptcp_pm_should_add_signal(msk) || 640 !(mptcp_pm_add_addr_signal(msk, remaining, &opts->addr, &echo, &port))) 641 return false; 642 643 len = mptcp_add_addr_len(opts->addr.family, echo, port); 644 if (remaining < len) 645 return false; 646 647 *size = len; 648 if (drop_other_suboptions) 649 *size -= opt_size; 650 opts->suboptions |= OPTION_MPTCP_ADD_ADDR; 651 if (!echo) { 652 opts->ahmac = add_addr_generate_hmac(msk->local_key, 653 msk->remote_key, 654 &opts->addr); 655 } 656 pr_debug("addr_id=%d, ahmac=%llu, echo=%d, port=%d", 657 opts->addr.id, opts->ahmac, echo, ntohs(opts->addr.port)); 658 659 return true; 660 } 661 662 static bool mptcp_established_options_rm_addr(struct sock *sk, 663 unsigned int *size, 664 unsigned int remaining, 665 struct mptcp_out_options *opts) 666 { 667 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 668 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 669 struct mptcp_rm_list rm_list; 670 int i, len; 671 672 if (!mptcp_pm_should_rm_signal(msk) || 673 !(mptcp_pm_rm_addr_signal(msk, remaining, &rm_list))) 674 return false; 675 676 len = mptcp_rm_addr_len(&rm_list); 677 if (len < 0) 678 return false; 679 if (remaining < len) 680 return false; 681 682 *size = len; 683 opts->suboptions |= OPTION_MPTCP_RM_ADDR; 684 opts->rm_list = rm_list; 685 686 for (i = 0; i < opts->rm_list.nr; i++) 687 pr_debug("rm_list_ids[%d]=%d", i, opts->rm_list.ids[i]); 688 689 return true; 690 } 691 692 static bool mptcp_established_options_mp_prio(struct sock *sk, 693 unsigned int *size, 694 unsigned int remaining, 695 struct mptcp_out_options *opts) 696 { 697 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 698 699 if (!subflow->send_mp_prio) 700 return false; 701 702 /* account for the trailing 'nop' option */ 703 if (remaining < TCPOLEN_MPTCP_PRIO_ALIGN) 704 return false; 705 706 *size = TCPOLEN_MPTCP_PRIO_ALIGN; 707 opts->suboptions |= OPTION_MPTCP_PRIO; 708 opts->backup = subflow->request_bkup; 709 710 pr_debug("prio=%d", opts->backup); 711 712 return true; 713 } 714 715 static noinline void mptcp_established_options_rst(struct sock *sk, struct sk_buff *skb, 716 unsigned int *size, 717 unsigned int remaining, 718 struct mptcp_out_options *opts) 719 { 720 const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 721 722 if (remaining < TCPOLEN_MPTCP_RST) 723 return; 724 725 *size = TCPOLEN_MPTCP_RST; 726 opts->suboptions |= OPTION_MPTCP_RST; 727 opts->reset_transient = subflow->reset_transient; 728 opts->reset_reason = subflow->reset_reason; 729 } 730 731 bool mptcp_established_options(struct sock *sk, struct sk_buff *skb, 732 unsigned int *size, unsigned int remaining, 733 struct mptcp_out_options *opts) 734 { 735 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 736 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 737 unsigned int opt_size = 0; 738 bool snd_data_fin; 739 bool ret = false; 740 741 opts->suboptions = 0; 742 743 if (unlikely(__mptcp_check_fallback(msk))) 744 return false; 745 746 if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) { 747 mptcp_established_options_rst(sk, skb, size, remaining, opts); 748 return true; 749 } 750 751 snd_data_fin = mptcp_data_fin_enabled(msk); 752 if (mptcp_established_options_mp(sk, skb, snd_data_fin, &opt_size, remaining, opts)) 753 ret = true; 754 else if (mptcp_established_options_dss(sk, skb, snd_data_fin, &opt_size, remaining, opts)) 755 ret = true; 756 757 /* we reserved enough space for the above options, and exceeding the 758 * TCP option space would be fatal 759 */ 760 if (WARN_ON_ONCE(opt_size > remaining)) 761 return false; 762 763 *size += opt_size; 764 remaining -= opt_size; 765 if (mptcp_established_options_add_addr(sk, skb, &opt_size, remaining, opts)) { 766 *size += opt_size; 767 remaining -= opt_size; 768 ret = true; 769 } else if (mptcp_established_options_rm_addr(sk, &opt_size, remaining, opts)) { 770 *size += opt_size; 771 remaining -= opt_size; 772 ret = true; 773 } 774 775 if (mptcp_established_options_mp_prio(sk, &opt_size, remaining, opts)) { 776 *size += opt_size; 777 remaining -= opt_size; 778 ret = true; 779 } 780 781 return ret; 782 } 783 784 bool mptcp_synack_options(const struct request_sock *req, unsigned int *size, 785 struct mptcp_out_options *opts) 786 { 787 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); 788 789 if (subflow_req->mp_capable) { 790 opts->suboptions = OPTION_MPTCP_MPC_SYNACK; 791 opts->sndr_key = subflow_req->local_key; 792 *size = TCPOLEN_MPTCP_MPC_SYNACK; 793 pr_debug("subflow_req=%p, local_key=%llu", 794 subflow_req, subflow_req->local_key); 795 return true; 796 } else if (subflow_req->mp_join) { 797 opts->suboptions = OPTION_MPTCP_MPJ_SYNACK; 798 opts->backup = subflow_req->backup; 799 opts->join_id = subflow_req->local_id; 800 opts->thmac = subflow_req->thmac; 801 opts->nonce = subflow_req->local_nonce; 802 pr_debug("req=%p, bkup=%u, id=%u, thmac=%llu, nonce=%u", 803 subflow_req, opts->backup, opts->join_id, 804 opts->thmac, opts->nonce); 805 *size = TCPOLEN_MPTCP_MPJ_SYNACK; 806 return true; 807 } 808 return false; 809 } 810 811 static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk, 812 struct mptcp_subflow_context *subflow, 813 struct sk_buff *skb, 814 struct mptcp_options_received *mp_opt) 815 { 816 /* here we can process OoO, in-window pkts, only in-sequence 4th ack 817 * will make the subflow fully established 818 */ 819 if (likely(subflow->fully_established)) { 820 /* on passive sockets, check for 3rd ack retransmission 821 * note that msk is always set by subflow_syn_recv_sock() 822 * for mp_join subflows 823 */ 824 if (TCP_SKB_CB(skb)->seq == subflow->ssn_offset + 1 && 825 TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq && 826 subflow->mp_join && mp_opt->mp_join && 827 READ_ONCE(msk->pm.server_side)) 828 tcp_send_ack(ssk); 829 goto fully_established; 830 } 831 832 /* we must process OoO packets before the first subflow is fully 833 * established. OoO packets are instead a protocol violation 834 * for MP_JOIN subflows as the peer must not send any data 835 * before receiving the forth ack - cfr. RFC 8684 section 3.2. 836 */ 837 if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) { 838 if (subflow->mp_join) 839 goto reset; 840 return subflow->mp_capable; 841 } 842 843 if (mp_opt->dss && mp_opt->use_ack) { 844 /* subflows are fully established as soon as we get any 845 * additional ack. 846 */ 847 subflow->fully_established = 1; 848 WRITE_ONCE(msk->fully_established, true); 849 goto fully_established; 850 } 851 852 if (mp_opt->add_addr) { 853 WRITE_ONCE(msk->fully_established, true); 854 return true; 855 } 856 857 /* If the first established packet does not contain MP_CAPABLE + data 858 * then fallback to TCP. Fallback scenarios requires a reset for 859 * MP_JOIN subflows. 860 */ 861 if (!mp_opt->mp_capable) { 862 if (subflow->mp_join) 863 goto reset; 864 subflow->mp_capable = 0; 865 pr_fallback(msk); 866 __mptcp_do_fallback(msk); 867 return false; 868 } 869 870 if (unlikely(!READ_ONCE(msk->pm.server_side))) 871 pr_warn_once("bogus mpc option on established client sk"); 872 mptcp_subflow_fully_established(subflow, mp_opt); 873 874 fully_established: 875 /* if the subflow is not already linked into the conn_list, we can't 876 * notify the PM: this subflow is still on the listener queue 877 * and the PM possibly acquiring the subflow lock could race with 878 * the listener close 879 */ 880 if (likely(subflow->pm_notified) || list_empty(&subflow->node)) 881 return true; 882 883 subflow->pm_notified = 1; 884 if (subflow->mp_join) { 885 clear_3rdack_retransmission(ssk); 886 mptcp_pm_subflow_established(msk); 887 } else { 888 mptcp_pm_fully_established(msk, ssk, GFP_ATOMIC); 889 } 890 return true; 891 892 reset: 893 mptcp_subflow_reset(ssk); 894 return false; 895 } 896 897 static u64 expand_ack(u64 old_ack, u64 cur_ack, bool use_64bit) 898 { 899 u32 old_ack32, cur_ack32; 900 901 if (use_64bit) 902 return cur_ack; 903 904 old_ack32 = (u32)old_ack; 905 cur_ack32 = (u32)cur_ack; 906 cur_ack = (old_ack & GENMASK_ULL(63, 32)) + cur_ack32; 907 if (unlikely(before(cur_ack32, old_ack32))) 908 return cur_ack + (1LL << 32); 909 return cur_ack; 910 } 911 912 static void ack_update_msk(struct mptcp_sock *msk, 913 struct sock *ssk, 914 struct mptcp_options_received *mp_opt) 915 { 916 u64 new_wnd_end, new_snd_una, snd_nxt = READ_ONCE(msk->snd_nxt); 917 struct sock *sk = (struct sock *)msk; 918 u64 old_snd_una; 919 920 mptcp_data_lock(sk); 921 922 /* avoid ack expansion on update conflict, to reduce the risk of 923 * wrongly expanding to a future ack sequence number, which is way 924 * more dangerous than missing an ack 925 */ 926 old_snd_una = msk->snd_una; 927 new_snd_una = expand_ack(old_snd_una, mp_opt->data_ack, mp_opt->ack64); 928 929 /* ACK for data not even sent yet? Ignore. */ 930 if (after64(new_snd_una, snd_nxt)) 931 new_snd_una = old_snd_una; 932 933 new_wnd_end = new_snd_una + tcp_sk(ssk)->snd_wnd; 934 935 if (after64(new_wnd_end, msk->wnd_end)) 936 msk->wnd_end = new_wnd_end; 937 938 /* this assumes mptcp_incoming_options() is invoked after tcp_ack() */ 939 if (after64(msk->wnd_end, READ_ONCE(msk->snd_nxt))) 940 __mptcp_check_push(sk, ssk); 941 942 if (after64(new_snd_una, old_snd_una)) { 943 msk->snd_una = new_snd_una; 944 __mptcp_data_acked(sk); 945 } 946 mptcp_data_unlock(sk); 947 948 trace_ack_update_msk(mp_opt->data_ack, 949 old_snd_una, new_snd_una, 950 new_wnd_end, msk->wnd_end); 951 } 952 953 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit) 954 { 955 /* Skip if DATA_FIN was already received. 956 * If updating simultaneously with the recvmsg loop, values 957 * should match. If they mismatch, the peer is misbehaving and 958 * we will prefer the most recent information. 959 */ 960 if (READ_ONCE(msk->rcv_data_fin)) 961 return false; 962 963 WRITE_ONCE(msk->rcv_data_fin_seq, 964 expand_ack(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit)); 965 WRITE_ONCE(msk->rcv_data_fin, 1); 966 967 return true; 968 } 969 970 static bool add_addr_hmac_valid(struct mptcp_sock *msk, 971 struct mptcp_options_received *mp_opt) 972 { 973 u64 hmac = 0; 974 975 if (mp_opt->echo) 976 return true; 977 978 hmac = add_addr_generate_hmac(msk->remote_key, 979 msk->local_key, 980 &mp_opt->addr); 981 982 pr_debug("msk=%p, ahmac=%llu, mp_opt->ahmac=%llu\n", 983 msk, (unsigned long long)hmac, 984 (unsigned long long)mp_opt->ahmac); 985 986 return hmac == mp_opt->ahmac; 987 } 988 989 void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb) 990 { 991 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 992 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 993 struct mptcp_options_received mp_opt; 994 struct mptcp_ext *mpext; 995 996 if (__mptcp_check_fallback(msk)) { 997 /* Keep it simple and unconditionally trigger send data cleanup and 998 * pending queue spooling. We will need to acquire the data lock 999 * for more accurate checks, and once the lock is acquired, such 1000 * helpers are cheap. 1001 */ 1002 mptcp_data_lock(subflow->conn); 1003 if (sk_stream_memory_free(sk)) 1004 __mptcp_check_push(subflow->conn, sk); 1005 __mptcp_data_acked(subflow->conn); 1006 mptcp_data_unlock(subflow->conn); 1007 return; 1008 } 1009 1010 mptcp_get_options(skb, &mp_opt); 1011 if (!check_fully_established(msk, sk, subflow, skb, &mp_opt)) 1012 return; 1013 1014 if (mp_opt.fastclose && 1015 msk->local_key == mp_opt.rcvr_key) { 1016 WRITE_ONCE(msk->rcv_fastclose, true); 1017 mptcp_schedule_work((struct sock *)msk); 1018 } 1019 1020 if (mp_opt.add_addr && add_addr_hmac_valid(msk, &mp_opt)) { 1021 if (!mp_opt.echo) { 1022 mptcp_pm_add_addr_received(msk, &mp_opt.addr); 1023 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR); 1024 } else { 1025 mptcp_pm_add_addr_echoed(msk, &mp_opt.addr); 1026 mptcp_pm_del_add_timer(msk, &mp_opt.addr, true); 1027 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD); 1028 } 1029 1030 if (mp_opt.addr.port) 1031 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_PORTADD); 1032 1033 mp_opt.add_addr = 0; 1034 } 1035 1036 if (mp_opt.rm_addr) { 1037 mptcp_pm_rm_addr_received(msk, &mp_opt.rm_list); 1038 mp_opt.rm_addr = 0; 1039 } 1040 1041 if (mp_opt.mp_prio) { 1042 mptcp_pm_mp_prio_received(sk, mp_opt.backup); 1043 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPPRIORX); 1044 mp_opt.mp_prio = 0; 1045 } 1046 1047 if (mp_opt.reset) { 1048 subflow->reset_seen = 1; 1049 subflow->reset_reason = mp_opt.reset_reason; 1050 subflow->reset_transient = mp_opt.reset_transient; 1051 } 1052 1053 if (!mp_opt.dss) 1054 return; 1055 1056 /* we can't wait for recvmsg() to update the ack_seq, otherwise 1057 * monodirectional flows will stuck 1058 */ 1059 if (mp_opt.use_ack) 1060 ack_update_msk(msk, sk, &mp_opt); 1061 1062 /* Zero-data-length packets are dropped by the caller and not 1063 * propagated to the MPTCP layer, so the skb extension does not 1064 * need to be allocated or populated. DATA_FIN information, if 1065 * present, needs to be updated here before the skb is freed. 1066 */ 1067 if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) { 1068 if (mp_opt.data_fin && mp_opt.data_len == 1 && 1069 mptcp_update_rcv_data_fin(msk, mp_opt.data_seq, mp_opt.dsn64) && 1070 schedule_work(&msk->work)) 1071 sock_hold(subflow->conn); 1072 1073 return; 1074 } 1075 1076 mpext = skb_ext_add(skb, SKB_EXT_MPTCP); 1077 if (!mpext) 1078 return; 1079 1080 memset(mpext, 0, sizeof(*mpext)); 1081 1082 if (mp_opt.use_map) { 1083 if (mp_opt.mpc_map) { 1084 /* this is an MP_CAPABLE carrying MPTCP data 1085 * we know this map the first chunk of data 1086 */ 1087 mptcp_crypto_key_sha(subflow->remote_key, NULL, 1088 &mpext->data_seq); 1089 mpext->data_seq++; 1090 mpext->subflow_seq = 1; 1091 mpext->dsn64 = 1; 1092 mpext->mpc_map = 1; 1093 mpext->data_fin = 0; 1094 } else { 1095 mpext->data_seq = mp_opt.data_seq; 1096 mpext->subflow_seq = mp_opt.subflow_seq; 1097 mpext->dsn64 = mp_opt.dsn64; 1098 mpext->data_fin = mp_opt.data_fin; 1099 } 1100 mpext->data_len = mp_opt.data_len; 1101 mpext->use_map = 1; 1102 } 1103 } 1104 1105 static void mptcp_set_rwin(const struct tcp_sock *tp) 1106 { 1107 const struct sock *ssk = (const struct sock *)tp; 1108 const struct mptcp_subflow_context *subflow; 1109 struct mptcp_sock *msk; 1110 u64 ack_seq; 1111 1112 subflow = mptcp_subflow_ctx(ssk); 1113 msk = mptcp_sk(subflow->conn); 1114 1115 ack_seq = READ_ONCE(msk->ack_seq) + tp->rcv_wnd; 1116 1117 if (after64(ack_seq, READ_ONCE(msk->rcv_wnd_sent))) 1118 WRITE_ONCE(msk->rcv_wnd_sent, ack_seq); 1119 } 1120 1121 void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp, 1122 struct mptcp_out_options *opts) 1123 { 1124 if ((OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK | 1125 OPTION_MPTCP_MPC_ACK) & opts->suboptions) { 1126 u8 len; 1127 1128 if (OPTION_MPTCP_MPC_SYN & opts->suboptions) 1129 len = TCPOLEN_MPTCP_MPC_SYN; 1130 else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions) 1131 len = TCPOLEN_MPTCP_MPC_SYNACK; 1132 else if (opts->ext_copy.data_len) 1133 len = TCPOLEN_MPTCP_MPC_ACK_DATA; 1134 else 1135 len = TCPOLEN_MPTCP_MPC_ACK; 1136 1137 *ptr++ = mptcp_option(MPTCPOPT_MP_CAPABLE, len, 1138 MPTCP_SUPPORTED_VERSION, 1139 MPTCP_CAP_HMAC_SHA256); 1140 1141 if (!((OPTION_MPTCP_MPC_SYNACK | OPTION_MPTCP_MPC_ACK) & 1142 opts->suboptions)) 1143 goto mp_capable_done; 1144 1145 put_unaligned_be64(opts->sndr_key, ptr); 1146 ptr += 2; 1147 if (!((OPTION_MPTCP_MPC_ACK) & opts->suboptions)) 1148 goto mp_capable_done; 1149 1150 put_unaligned_be64(opts->rcvr_key, ptr); 1151 ptr += 2; 1152 if (!opts->ext_copy.data_len) 1153 goto mp_capable_done; 1154 1155 put_unaligned_be32(opts->ext_copy.data_len << 16 | 1156 TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); 1157 ptr += 1; 1158 } 1159 1160 mp_capable_done: 1161 if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) { 1162 u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE; 1163 u8 echo = MPTCP_ADDR_ECHO; 1164 1165 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 1166 if (opts->addr.family == AF_INET6) 1167 len = TCPOLEN_MPTCP_ADD_ADDR6_BASE; 1168 #endif 1169 1170 if (opts->addr.port) 1171 len += TCPOLEN_MPTCP_PORT_LEN; 1172 1173 if (opts->ahmac) { 1174 len += sizeof(opts->ahmac); 1175 echo = 0; 1176 } 1177 1178 *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR, 1179 len, echo, opts->addr.id); 1180 if (opts->addr.family == AF_INET) { 1181 memcpy((u8 *)ptr, (u8 *)&opts->addr.addr.s_addr, 4); 1182 ptr += 1; 1183 } 1184 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 1185 else if (opts->addr.family == AF_INET6) { 1186 memcpy((u8 *)ptr, opts->addr.addr6.s6_addr, 16); 1187 ptr += 4; 1188 } 1189 #endif 1190 1191 if (!opts->addr.port) { 1192 if (opts->ahmac) { 1193 put_unaligned_be64(opts->ahmac, ptr); 1194 ptr += 2; 1195 } 1196 } else { 1197 u16 port = ntohs(opts->addr.port); 1198 1199 if (opts->ahmac) { 1200 u8 *bptr = (u8 *)ptr; 1201 1202 put_unaligned_be16(port, bptr); 1203 bptr += 2; 1204 put_unaligned_be64(opts->ahmac, bptr); 1205 bptr += 8; 1206 put_unaligned_be16(TCPOPT_NOP << 8 | 1207 TCPOPT_NOP, bptr); 1208 1209 ptr += 3; 1210 } else { 1211 put_unaligned_be32(port << 16 | 1212 TCPOPT_NOP << 8 | 1213 TCPOPT_NOP, ptr); 1214 ptr += 1; 1215 } 1216 } 1217 } 1218 1219 if (OPTION_MPTCP_RM_ADDR & opts->suboptions) { 1220 u8 i = 1; 1221 1222 *ptr++ = mptcp_option(MPTCPOPT_RM_ADDR, 1223 TCPOLEN_MPTCP_RM_ADDR_BASE + opts->rm_list.nr, 1224 0, opts->rm_list.ids[0]); 1225 1226 while (i < opts->rm_list.nr) { 1227 u8 id1, id2, id3, id4; 1228 1229 id1 = opts->rm_list.ids[i]; 1230 id2 = i + 1 < opts->rm_list.nr ? opts->rm_list.ids[i + 1] : TCPOPT_NOP; 1231 id3 = i + 2 < opts->rm_list.nr ? opts->rm_list.ids[i + 2] : TCPOPT_NOP; 1232 id4 = i + 3 < opts->rm_list.nr ? opts->rm_list.ids[i + 3] : TCPOPT_NOP; 1233 put_unaligned_be32(id1 << 24 | id2 << 16 | id3 << 8 | id4, ptr); 1234 ptr += 1; 1235 i += 4; 1236 } 1237 } 1238 1239 if (OPTION_MPTCP_PRIO & opts->suboptions) { 1240 const struct sock *ssk = (const struct sock *)tp; 1241 struct mptcp_subflow_context *subflow; 1242 1243 subflow = mptcp_subflow_ctx(ssk); 1244 subflow->send_mp_prio = 0; 1245 1246 *ptr++ = mptcp_option(MPTCPOPT_MP_PRIO, 1247 TCPOLEN_MPTCP_PRIO, 1248 opts->backup, TCPOPT_NOP); 1249 } 1250 1251 if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) { 1252 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, 1253 TCPOLEN_MPTCP_MPJ_SYN, 1254 opts->backup, opts->join_id); 1255 put_unaligned_be32(opts->token, ptr); 1256 ptr += 1; 1257 put_unaligned_be32(opts->nonce, ptr); 1258 ptr += 1; 1259 } 1260 1261 if (OPTION_MPTCP_MPJ_SYNACK & opts->suboptions) { 1262 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, 1263 TCPOLEN_MPTCP_MPJ_SYNACK, 1264 opts->backup, opts->join_id); 1265 put_unaligned_be64(opts->thmac, ptr); 1266 ptr += 2; 1267 put_unaligned_be32(opts->nonce, ptr); 1268 ptr += 1; 1269 } 1270 1271 if (OPTION_MPTCP_MPJ_ACK & opts->suboptions) { 1272 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, 1273 TCPOLEN_MPTCP_MPJ_ACK, 0, 0); 1274 memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN); 1275 ptr += 5; 1276 } 1277 1278 if (OPTION_MPTCP_RST & opts->suboptions) 1279 *ptr++ = mptcp_option(MPTCPOPT_RST, 1280 TCPOLEN_MPTCP_RST, 1281 opts->reset_transient, 1282 opts->reset_reason); 1283 1284 if (opts->ext_copy.use_ack || opts->ext_copy.use_map) { 1285 struct mptcp_ext *mpext = &opts->ext_copy; 1286 u8 len = TCPOLEN_MPTCP_DSS_BASE; 1287 u8 flags = 0; 1288 1289 if (mpext->use_ack) { 1290 flags = MPTCP_DSS_HAS_ACK; 1291 if (mpext->ack64) { 1292 len += TCPOLEN_MPTCP_DSS_ACK64; 1293 flags |= MPTCP_DSS_ACK64; 1294 } else { 1295 len += TCPOLEN_MPTCP_DSS_ACK32; 1296 } 1297 } 1298 1299 if (mpext->use_map) { 1300 len += TCPOLEN_MPTCP_DSS_MAP64; 1301 1302 /* Use only 64-bit mapping flags for now, add 1303 * support for optional 32-bit mappings later. 1304 */ 1305 flags |= MPTCP_DSS_HAS_MAP | MPTCP_DSS_DSN64; 1306 if (mpext->data_fin) 1307 flags |= MPTCP_DSS_DATA_FIN; 1308 } 1309 1310 *ptr++ = mptcp_option(MPTCPOPT_DSS, len, 0, flags); 1311 1312 if (mpext->use_ack) { 1313 if (mpext->ack64) { 1314 put_unaligned_be64(mpext->data_ack, ptr); 1315 ptr += 2; 1316 } else { 1317 put_unaligned_be32(mpext->data_ack32, ptr); 1318 ptr += 1; 1319 } 1320 } 1321 1322 if (mpext->use_map) { 1323 put_unaligned_be64(mpext->data_seq, ptr); 1324 ptr += 2; 1325 put_unaligned_be32(mpext->subflow_seq, ptr); 1326 ptr += 1; 1327 put_unaligned_be32(mpext->data_len << 16 | 1328 TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); 1329 } 1330 } 1331 1332 if (tp) 1333 mptcp_set_rwin(tp); 1334 } 1335 1336 __be32 mptcp_get_reset_option(const struct sk_buff *skb) 1337 { 1338 const struct mptcp_ext *ext = mptcp_get_ext(skb); 1339 u8 flags, reason; 1340 1341 if (ext) { 1342 flags = ext->reset_transient; 1343 reason = ext->reset_reason; 1344 1345 return mptcp_option(MPTCPOPT_RST, TCPOLEN_MPTCP_RST, 1346 flags, reason); 1347 } 1348 1349 return htonl(0u); 1350 } 1351 EXPORT_SYMBOL_GPL(mptcp_get_reset_option); 1352