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 if (length < 2) 360 return; 361 opsize = *ptr++; 362 if (opsize < 2) /* "silly options" */ 363 return; 364 if (opsize > length) 365 return; /* don't parse partial options */ 366 if (opcode == TCPOPT_MPTCP) 367 mptcp_parse_option(skb, ptr, opsize, mp_opt); 368 ptr += opsize - 2; 369 length -= opsize; 370 } 371 } 372 } 373 374 bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb, 375 unsigned int *size, struct mptcp_out_options *opts) 376 { 377 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 378 379 /* we will use snd_isn to detect first pkt [re]transmission 380 * in mptcp_established_options_mp() 381 */ 382 subflow->snd_isn = TCP_SKB_CB(skb)->end_seq; 383 if (subflow->request_mptcp) { 384 opts->suboptions = OPTION_MPTCP_MPC_SYN; 385 *size = TCPOLEN_MPTCP_MPC_SYN; 386 return true; 387 } else if (subflow->request_join) { 388 pr_debug("remote_token=%u, nonce=%u", subflow->remote_token, 389 subflow->local_nonce); 390 opts->suboptions = OPTION_MPTCP_MPJ_SYN; 391 opts->join_id = subflow->local_id; 392 opts->token = subflow->remote_token; 393 opts->nonce = subflow->local_nonce; 394 opts->backup = subflow->request_bkup; 395 *size = TCPOLEN_MPTCP_MPJ_SYN; 396 return true; 397 } 398 return false; 399 } 400 401 /* MP_JOIN client subflow must wait for 4th ack before sending any data: 402 * TCP can't schedule delack timer before the subflow is fully established. 403 * MPTCP uses the delack timer to do 3rd ack retransmissions 404 */ 405 static void schedule_3rdack_retransmission(struct sock *sk) 406 { 407 struct inet_connection_sock *icsk = inet_csk(sk); 408 struct tcp_sock *tp = tcp_sk(sk); 409 unsigned long timeout; 410 411 /* reschedule with a timeout above RTT, as we must look only for drop */ 412 if (tp->srtt_us) 413 timeout = tp->srtt_us << 1; 414 else 415 timeout = TCP_TIMEOUT_INIT; 416 417 WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER); 418 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; 419 icsk->icsk_ack.timeout = timeout; 420 sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout); 421 } 422 423 static void clear_3rdack_retransmission(struct sock *sk) 424 { 425 struct inet_connection_sock *icsk = inet_csk(sk); 426 427 sk_stop_timer(sk, &icsk->icsk_delack_timer); 428 icsk->icsk_ack.timeout = 0; 429 icsk->icsk_ack.ato = 0; 430 icsk->icsk_ack.pending &= ~(ICSK_ACK_SCHED | ICSK_ACK_TIMER); 431 } 432 433 static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb, 434 bool snd_data_fin_enable, 435 unsigned int *size, 436 unsigned int remaining, 437 struct mptcp_out_options *opts) 438 { 439 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 440 struct mptcp_ext *mpext; 441 unsigned int data_len; 442 443 /* When skb is not available, we better over-estimate the emitted 444 * options len. A full DSS option (28 bytes) is longer than 445 * TCPOLEN_MPTCP_MPC_ACK_DATA(22) or TCPOLEN_MPTCP_MPJ_ACK(24), so 446 * tell the caller to defer the estimate to 447 * mptcp_established_options_dss(), which will reserve enough space. 448 */ 449 if (!skb) 450 return false; 451 452 /* MPC/MPJ needed only on 3rd ack packet, DATA_FIN and TCP shutdown take precedence */ 453 if (subflow->fully_established || snd_data_fin_enable || 454 subflow->snd_isn != TCP_SKB_CB(skb)->seq || 455 sk->sk_state != TCP_ESTABLISHED) 456 return false; 457 458 if (subflow->mp_capable) { 459 mpext = mptcp_get_ext(skb); 460 data_len = mpext ? mpext->data_len : 0; 461 462 /* we will check ext_copy.data_len in mptcp_write_options() to 463 * discriminate between TCPOLEN_MPTCP_MPC_ACK_DATA and 464 * TCPOLEN_MPTCP_MPC_ACK 465 */ 466 opts->ext_copy.data_len = data_len; 467 opts->suboptions = OPTION_MPTCP_MPC_ACK; 468 opts->sndr_key = subflow->local_key; 469 opts->rcvr_key = subflow->remote_key; 470 471 /* Section 3.1. 472 * The MP_CAPABLE option is carried on the SYN, SYN/ACK, and ACK 473 * packets that start the first subflow of an MPTCP connection, 474 * as well as the first packet that carries data 475 */ 476 if (data_len > 0) 477 *size = ALIGN(TCPOLEN_MPTCP_MPC_ACK_DATA, 4); 478 else 479 *size = TCPOLEN_MPTCP_MPC_ACK; 480 481 pr_debug("subflow=%p, local_key=%llu, remote_key=%llu map_len=%d", 482 subflow, subflow->local_key, subflow->remote_key, 483 data_len); 484 485 return true; 486 } else if (subflow->mp_join) { 487 opts->suboptions = OPTION_MPTCP_MPJ_ACK; 488 memcpy(opts->hmac, subflow->hmac, MPTCPOPT_HMAC_LEN); 489 *size = TCPOLEN_MPTCP_MPJ_ACK; 490 pr_debug("subflow=%p", subflow); 491 492 schedule_3rdack_retransmission(sk); 493 return true; 494 } 495 return false; 496 } 497 498 static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow, 499 struct sk_buff *skb, struct mptcp_ext *ext) 500 { 501 /* The write_seq value has already been incremented, so the actual 502 * sequence number for the DATA_FIN is one less. 503 */ 504 u64 data_fin_tx_seq = READ_ONCE(mptcp_sk(subflow->conn)->write_seq) - 1; 505 506 if (!ext->use_map || !skb->len) { 507 /* RFC6824 requires a DSS mapping with specific values 508 * if DATA_FIN is set but no data payload is mapped 509 */ 510 ext->data_fin = 1; 511 ext->use_map = 1; 512 ext->dsn64 = 1; 513 ext->data_seq = data_fin_tx_seq; 514 ext->subflow_seq = 0; 515 ext->data_len = 1; 516 } else if (ext->data_seq + ext->data_len == data_fin_tx_seq) { 517 /* If there's an existing DSS mapping and it is the 518 * final mapping, DATA_FIN consumes 1 additional byte of 519 * mapping space. 520 */ 521 ext->data_fin = 1; 522 ext->data_len++; 523 } 524 } 525 526 static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb, 527 bool snd_data_fin_enable, 528 unsigned int *size, 529 unsigned int remaining, 530 struct mptcp_out_options *opts) 531 { 532 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 533 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 534 unsigned int dss_size = 0; 535 struct mptcp_ext *mpext; 536 unsigned int ack_size; 537 bool ret = false; 538 u64 ack_seq; 539 540 mpext = skb ? mptcp_get_ext(skb) : NULL; 541 542 if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) { 543 unsigned int map_size; 544 545 map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64; 546 547 remaining -= map_size; 548 dss_size = map_size; 549 if (mpext) 550 opts->ext_copy = *mpext; 551 552 if (skb && snd_data_fin_enable) 553 mptcp_write_data_fin(subflow, skb, &opts->ext_copy); 554 ret = true; 555 } 556 557 /* passive sockets msk will set the 'can_ack' after accept(), even 558 * if the first subflow may have the already the remote key handy 559 */ 560 opts->ext_copy.use_ack = 0; 561 if (!READ_ONCE(msk->can_ack)) { 562 *size = ALIGN(dss_size, 4); 563 return ret; 564 } 565 566 ack_seq = READ_ONCE(msk->ack_seq); 567 if (READ_ONCE(msk->use_64bit_ack)) { 568 ack_size = TCPOLEN_MPTCP_DSS_ACK64; 569 opts->ext_copy.data_ack = ack_seq; 570 opts->ext_copy.ack64 = 1; 571 } else { 572 ack_size = TCPOLEN_MPTCP_DSS_ACK32; 573 opts->ext_copy.data_ack32 = (uint32_t)ack_seq; 574 opts->ext_copy.ack64 = 0; 575 } 576 opts->ext_copy.use_ack = 1; 577 WRITE_ONCE(msk->old_wspace, __mptcp_space((struct sock *)msk)); 578 579 /* Add kind/length/subtype/flag overhead if mapping is not populated */ 580 if (dss_size == 0) 581 ack_size += TCPOLEN_MPTCP_DSS_BASE; 582 583 dss_size += ack_size; 584 585 *size = ALIGN(dss_size, 4); 586 return true; 587 } 588 589 static u64 add_addr_generate_hmac(u64 key1, u64 key2, 590 struct mptcp_addr_info *addr) 591 { 592 u16 port = ntohs(addr->port); 593 u8 hmac[SHA256_DIGEST_SIZE]; 594 u8 msg[19]; 595 int i = 0; 596 597 msg[i++] = addr->id; 598 if (addr->family == AF_INET) { 599 memcpy(&msg[i], &addr->addr.s_addr, 4); 600 i += 4; 601 } 602 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 603 else if (addr->family == AF_INET6) { 604 memcpy(&msg[i], &addr->addr6.s6_addr, 16); 605 i += 16; 606 } 607 #endif 608 msg[i++] = port >> 8; 609 msg[i++] = port & 0xFF; 610 611 mptcp_crypto_hmac_sha(key1, key2, msg, i, hmac); 612 613 return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]); 614 } 615 616 static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *skb, 617 unsigned int *size, 618 unsigned int remaining, 619 struct mptcp_out_options *opts) 620 { 621 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 622 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 623 bool drop_other_suboptions = false; 624 unsigned int opt_size = *size; 625 bool echo; 626 bool port; 627 int len; 628 629 if ((mptcp_pm_should_add_signal_ipv6(msk) || 630 mptcp_pm_should_add_signal_port(msk) || 631 mptcp_pm_should_add_signal_echo(msk)) && 632 skb && skb_is_tcp_pure_ack(skb)) { 633 pr_debug("drop other suboptions"); 634 opts->suboptions = 0; 635 opts->ext_copy.use_ack = 0; 636 opts->ext_copy.use_map = 0; 637 remaining += opt_size; 638 drop_other_suboptions = true; 639 } 640 641 if (!mptcp_pm_should_add_signal(msk) || 642 !(mptcp_pm_add_addr_signal(msk, remaining, &opts->addr, &echo, &port))) 643 return false; 644 645 len = mptcp_add_addr_len(opts->addr.family, echo, port); 646 if (remaining < len) 647 return false; 648 649 *size = len; 650 if (drop_other_suboptions) 651 *size -= opt_size; 652 opts->suboptions |= OPTION_MPTCP_ADD_ADDR; 653 if (!echo) { 654 opts->ahmac = add_addr_generate_hmac(msk->local_key, 655 msk->remote_key, 656 &opts->addr); 657 } 658 pr_debug("addr_id=%d, ahmac=%llu, echo=%d, port=%d", 659 opts->addr.id, opts->ahmac, echo, ntohs(opts->addr.port)); 660 661 return true; 662 } 663 664 static bool mptcp_established_options_rm_addr(struct sock *sk, 665 unsigned int *size, 666 unsigned int remaining, 667 struct mptcp_out_options *opts) 668 { 669 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 670 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 671 struct mptcp_rm_list rm_list; 672 int i, len; 673 674 if (!mptcp_pm_should_rm_signal(msk) || 675 !(mptcp_pm_rm_addr_signal(msk, remaining, &rm_list))) 676 return false; 677 678 len = mptcp_rm_addr_len(&rm_list); 679 if (len < 0) 680 return false; 681 if (remaining < len) 682 return false; 683 684 *size = len; 685 opts->suboptions |= OPTION_MPTCP_RM_ADDR; 686 opts->rm_list = rm_list; 687 688 for (i = 0; i < opts->rm_list.nr; i++) 689 pr_debug("rm_list_ids[%d]=%d", i, opts->rm_list.ids[i]); 690 691 return true; 692 } 693 694 static bool mptcp_established_options_mp_prio(struct sock *sk, 695 unsigned int *size, 696 unsigned int remaining, 697 struct mptcp_out_options *opts) 698 { 699 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 700 701 if (!subflow->send_mp_prio) 702 return false; 703 704 /* account for the trailing 'nop' option */ 705 if (remaining < TCPOLEN_MPTCP_PRIO_ALIGN) 706 return false; 707 708 *size = TCPOLEN_MPTCP_PRIO_ALIGN; 709 opts->suboptions |= OPTION_MPTCP_PRIO; 710 opts->backup = subflow->request_bkup; 711 712 pr_debug("prio=%d", opts->backup); 713 714 return true; 715 } 716 717 static noinline void mptcp_established_options_rst(struct sock *sk, struct sk_buff *skb, 718 unsigned int *size, 719 unsigned int remaining, 720 struct mptcp_out_options *opts) 721 { 722 const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 723 724 if (remaining < TCPOLEN_MPTCP_RST) 725 return; 726 727 *size = TCPOLEN_MPTCP_RST; 728 opts->suboptions |= OPTION_MPTCP_RST; 729 opts->reset_transient = subflow->reset_transient; 730 opts->reset_reason = subflow->reset_reason; 731 } 732 733 bool mptcp_established_options(struct sock *sk, struct sk_buff *skb, 734 unsigned int *size, unsigned int remaining, 735 struct mptcp_out_options *opts) 736 { 737 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 738 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 739 unsigned int opt_size = 0; 740 bool snd_data_fin; 741 bool ret = false; 742 743 opts->suboptions = 0; 744 745 if (unlikely(__mptcp_check_fallback(msk))) 746 return false; 747 748 if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) { 749 mptcp_established_options_rst(sk, skb, size, remaining, opts); 750 return true; 751 } 752 753 snd_data_fin = mptcp_data_fin_enabled(msk); 754 if (mptcp_established_options_mp(sk, skb, snd_data_fin, &opt_size, remaining, opts)) 755 ret = true; 756 else if (mptcp_established_options_dss(sk, skb, snd_data_fin, &opt_size, remaining, opts)) 757 ret = true; 758 759 /* we reserved enough space for the above options, and exceeding the 760 * TCP option space would be fatal 761 */ 762 if (WARN_ON_ONCE(opt_size > remaining)) 763 return false; 764 765 *size += opt_size; 766 remaining -= opt_size; 767 if (mptcp_established_options_add_addr(sk, skb, &opt_size, remaining, opts)) { 768 *size += opt_size; 769 remaining -= opt_size; 770 ret = true; 771 } else if (mptcp_established_options_rm_addr(sk, &opt_size, remaining, opts)) { 772 *size += opt_size; 773 remaining -= opt_size; 774 ret = true; 775 } 776 777 if (mptcp_established_options_mp_prio(sk, &opt_size, remaining, opts)) { 778 *size += opt_size; 779 remaining -= opt_size; 780 ret = true; 781 } 782 783 return ret; 784 } 785 786 bool mptcp_synack_options(const struct request_sock *req, unsigned int *size, 787 struct mptcp_out_options *opts) 788 { 789 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); 790 791 if (subflow_req->mp_capable) { 792 opts->suboptions = OPTION_MPTCP_MPC_SYNACK; 793 opts->sndr_key = subflow_req->local_key; 794 *size = TCPOLEN_MPTCP_MPC_SYNACK; 795 pr_debug("subflow_req=%p, local_key=%llu", 796 subflow_req, subflow_req->local_key); 797 return true; 798 } else if (subflow_req->mp_join) { 799 opts->suboptions = OPTION_MPTCP_MPJ_SYNACK; 800 opts->backup = subflow_req->backup; 801 opts->join_id = subflow_req->local_id; 802 opts->thmac = subflow_req->thmac; 803 opts->nonce = subflow_req->local_nonce; 804 pr_debug("req=%p, bkup=%u, id=%u, thmac=%llu, nonce=%u", 805 subflow_req, opts->backup, opts->join_id, 806 opts->thmac, opts->nonce); 807 *size = TCPOLEN_MPTCP_MPJ_SYNACK; 808 return true; 809 } 810 return false; 811 } 812 813 static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk, 814 struct mptcp_subflow_context *subflow, 815 struct sk_buff *skb, 816 struct mptcp_options_received *mp_opt) 817 { 818 /* here we can process OoO, in-window pkts, only in-sequence 4th ack 819 * will make the subflow fully established 820 */ 821 if (likely(subflow->fully_established)) { 822 /* on passive sockets, check for 3rd ack retransmission 823 * note that msk is always set by subflow_syn_recv_sock() 824 * for mp_join subflows 825 */ 826 if (TCP_SKB_CB(skb)->seq == subflow->ssn_offset + 1 && 827 TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq && 828 subflow->mp_join && mp_opt->mp_join && 829 READ_ONCE(msk->pm.server_side)) 830 tcp_send_ack(ssk); 831 goto fully_established; 832 } 833 834 /* we must process OoO packets before the first subflow is fully 835 * established. OoO packets are instead a protocol violation 836 * for MP_JOIN subflows as the peer must not send any data 837 * before receiving the forth ack - cfr. RFC 8684 section 3.2. 838 */ 839 if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) { 840 if (subflow->mp_join) 841 goto reset; 842 return subflow->mp_capable; 843 } 844 845 if (mp_opt->dss && mp_opt->use_ack) { 846 /* subflows are fully established as soon as we get any 847 * additional ack. 848 */ 849 subflow->fully_established = 1; 850 WRITE_ONCE(msk->fully_established, true); 851 goto fully_established; 852 } 853 854 if (mp_opt->add_addr) { 855 WRITE_ONCE(msk->fully_established, true); 856 return true; 857 } 858 859 /* If the first established packet does not contain MP_CAPABLE + data 860 * then fallback to TCP. Fallback scenarios requires a reset for 861 * MP_JOIN subflows. 862 */ 863 if (!mp_opt->mp_capable) { 864 if (subflow->mp_join) 865 goto reset; 866 subflow->mp_capable = 0; 867 pr_fallback(msk); 868 __mptcp_do_fallback(msk); 869 return false; 870 } 871 872 if (unlikely(!READ_ONCE(msk->pm.server_side))) 873 pr_warn_once("bogus mpc option on established client sk"); 874 mptcp_subflow_fully_established(subflow, mp_opt); 875 876 fully_established: 877 /* if the subflow is not already linked into the conn_list, we can't 878 * notify the PM: this subflow is still on the listener queue 879 * and the PM possibly acquiring the subflow lock could race with 880 * the listener close 881 */ 882 if (likely(subflow->pm_notified) || list_empty(&subflow->node)) 883 return true; 884 885 subflow->pm_notified = 1; 886 if (subflow->mp_join) { 887 clear_3rdack_retransmission(ssk); 888 mptcp_pm_subflow_established(msk); 889 } else { 890 mptcp_pm_fully_established(msk, ssk, GFP_ATOMIC); 891 } 892 return true; 893 894 reset: 895 mptcp_subflow_reset(ssk); 896 return false; 897 } 898 899 static u64 expand_ack(u64 old_ack, u64 cur_ack, bool use_64bit) 900 { 901 u32 old_ack32, cur_ack32; 902 903 if (use_64bit) 904 return cur_ack; 905 906 old_ack32 = (u32)old_ack; 907 cur_ack32 = (u32)cur_ack; 908 cur_ack = (old_ack & GENMASK_ULL(63, 32)) + cur_ack32; 909 if (unlikely(before(cur_ack32, old_ack32))) 910 return cur_ack + (1LL << 32); 911 return cur_ack; 912 } 913 914 static void ack_update_msk(struct mptcp_sock *msk, 915 struct sock *ssk, 916 struct mptcp_options_received *mp_opt) 917 { 918 u64 new_wnd_end, new_snd_una, snd_nxt = READ_ONCE(msk->snd_nxt); 919 struct sock *sk = (struct sock *)msk; 920 u64 old_snd_una; 921 922 mptcp_data_lock(sk); 923 924 /* avoid ack expansion on update conflict, to reduce the risk of 925 * wrongly expanding to a future ack sequence number, which is way 926 * more dangerous than missing an ack 927 */ 928 old_snd_una = msk->snd_una; 929 new_snd_una = expand_ack(old_snd_una, mp_opt->data_ack, mp_opt->ack64); 930 931 /* ACK for data not even sent yet? Ignore. */ 932 if (after64(new_snd_una, snd_nxt)) 933 new_snd_una = old_snd_una; 934 935 new_wnd_end = new_snd_una + tcp_sk(ssk)->snd_wnd; 936 937 if (after64(new_wnd_end, msk->wnd_end)) 938 msk->wnd_end = new_wnd_end; 939 940 /* this assumes mptcp_incoming_options() is invoked after tcp_ack() */ 941 if (after64(msk->wnd_end, READ_ONCE(msk->snd_nxt))) 942 __mptcp_check_push(sk, ssk); 943 944 if (after64(new_snd_una, old_snd_una)) { 945 msk->snd_una = new_snd_una; 946 __mptcp_data_acked(sk); 947 } 948 mptcp_data_unlock(sk); 949 950 trace_ack_update_msk(mp_opt->data_ack, 951 old_snd_una, new_snd_una, 952 new_wnd_end, msk->wnd_end); 953 } 954 955 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit) 956 { 957 /* Skip if DATA_FIN was already received. 958 * If updating simultaneously with the recvmsg loop, values 959 * should match. If they mismatch, the peer is misbehaving and 960 * we will prefer the most recent information. 961 */ 962 if (READ_ONCE(msk->rcv_data_fin)) 963 return false; 964 965 WRITE_ONCE(msk->rcv_data_fin_seq, 966 expand_ack(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit)); 967 WRITE_ONCE(msk->rcv_data_fin, 1); 968 969 return true; 970 } 971 972 static bool add_addr_hmac_valid(struct mptcp_sock *msk, 973 struct mptcp_options_received *mp_opt) 974 { 975 u64 hmac = 0; 976 977 if (mp_opt->echo) 978 return true; 979 980 hmac = add_addr_generate_hmac(msk->remote_key, 981 msk->local_key, 982 &mp_opt->addr); 983 984 pr_debug("msk=%p, ahmac=%llu, mp_opt->ahmac=%llu\n", 985 msk, (unsigned long long)hmac, 986 (unsigned long long)mp_opt->ahmac); 987 988 return hmac == mp_opt->ahmac; 989 } 990 991 void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb) 992 { 993 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 994 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 995 struct mptcp_options_received mp_opt; 996 struct mptcp_ext *mpext; 997 998 if (__mptcp_check_fallback(msk)) { 999 /* Keep it simple and unconditionally trigger send data cleanup and 1000 * pending queue spooling. We will need to acquire the data lock 1001 * for more accurate checks, and once the lock is acquired, such 1002 * helpers are cheap. 1003 */ 1004 mptcp_data_lock(subflow->conn); 1005 if (sk_stream_memory_free(sk)) 1006 __mptcp_check_push(subflow->conn, sk); 1007 __mptcp_data_acked(subflow->conn); 1008 mptcp_data_unlock(subflow->conn); 1009 return; 1010 } 1011 1012 mptcp_get_options(skb, &mp_opt); 1013 if (!check_fully_established(msk, sk, subflow, skb, &mp_opt)) 1014 return; 1015 1016 if (mp_opt.fastclose && 1017 msk->local_key == mp_opt.rcvr_key) { 1018 WRITE_ONCE(msk->rcv_fastclose, true); 1019 mptcp_schedule_work((struct sock *)msk); 1020 } 1021 1022 if (mp_opt.add_addr && add_addr_hmac_valid(msk, &mp_opt)) { 1023 if (!mp_opt.echo) { 1024 mptcp_pm_add_addr_received(msk, &mp_opt.addr); 1025 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR); 1026 } else { 1027 mptcp_pm_add_addr_echoed(msk, &mp_opt.addr); 1028 mptcp_pm_del_add_timer(msk, &mp_opt.addr, true); 1029 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD); 1030 } 1031 1032 if (mp_opt.addr.port) 1033 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_PORTADD); 1034 1035 mp_opt.add_addr = 0; 1036 } 1037 1038 if (mp_opt.rm_addr) { 1039 mptcp_pm_rm_addr_received(msk, &mp_opt.rm_list); 1040 mp_opt.rm_addr = 0; 1041 } 1042 1043 if (mp_opt.mp_prio) { 1044 mptcp_pm_mp_prio_received(sk, mp_opt.backup); 1045 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPPRIORX); 1046 mp_opt.mp_prio = 0; 1047 } 1048 1049 if (mp_opt.reset) { 1050 subflow->reset_seen = 1; 1051 subflow->reset_reason = mp_opt.reset_reason; 1052 subflow->reset_transient = mp_opt.reset_transient; 1053 } 1054 1055 if (!mp_opt.dss) 1056 return; 1057 1058 /* we can't wait for recvmsg() to update the ack_seq, otherwise 1059 * monodirectional flows will stuck 1060 */ 1061 if (mp_opt.use_ack) 1062 ack_update_msk(msk, sk, &mp_opt); 1063 1064 /* Zero-data-length packets are dropped by the caller and not 1065 * propagated to the MPTCP layer, so the skb extension does not 1066 * need to be allocated or populated. DATA_FIN information, if 1067 * present, needs to be updated here before the skb is freed. 1068 */ 1069 if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) { 1070 if (mp_opt.data_fin && mp_opt.data_len == 1 && 1071 mptcp_update_rcv_data_fin(msk, mp_opt.data_seq, mp_opt.dsn64) && 1072 schedule_work(&msk->work)) 1073 sock_hold(subflow->conn); 1074 1075 return; 1076 } 1077 1078 mpext = skb_ext_add(skb, SKB_EXT_MPTCP); 1079 if (!mpext) 1080 return; 1081 1082 memset(mpext, 0, sizeof(*mpext)); 1083 1084 if (mp_opt.use_map) { 1085 if (mp_opt.mpc_map) { 1086 /* this is an MP_CAPABLE carrying MPTCP data 1087 * we know this map the first chunk of data 1088 */ 1089 mptcp_crypto_key_sha(subflow->remote_key, NULL, 1090 &mpext->data_seq); 1091 mpext->data_seq++; 1092 mpext->subflow_seq = 1; 1093 mpext->dsn64 = 1; 1094 mpext->mpc_map = 1; 1095 mpext->data_fin = 0; 1096 } else { 1097 mpext->data_seq = mp_opt.data_seq; 1098 mpext->subflow_seq = mp_opt.subflow_seq; 1099 mpext->dsn64 = mp_opt.dsn64; 1100 mpext->data_fin = mp_opt.data_fin; 1101 } 1102 mpext->data_len = mp_opt.data_len; 1103 mpext->use_map = 1; 1104 } 1105 } 1106 1107 static void mptcp_set_rwin(const struct tcp_sock *tp) 1108 { 1109 const struct sock *ssk = (const struct sock *)tp; 1110 const struct mptcp_subflow_context *subflow; 1111 struct mptcp_sock *msk; 1112 u64 ack_seq; 1113 1114 subflow = mptcp_subflow_ctx(ssk); 1115 msk = mptcp_sk(subflow->conn); 1116 1117 ack_seq = READ_ONCE(msk->ack_seq) + tp->rcv_wnd; 1118 1119 if (after64(ack_seq, READ_ONCE(msk->rcv_wnd_sent))) 1120 WRITE_ONCE(msk->rcv_wnd_sent, ack_seq); 1121 } 1122 1123 void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp, 1124 struct mptcp_out_options *opts) 1125 { 1126 if ((OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK | 1127 OPTION_MPTCP_MPC_ACK) & opts->suboptions) { 1128 u8 len; 1129 1130 if (OPTION_MPTCP_MPC_SYN & opts->suboptions) 1131 len = TCPOLEN_MPTCP_MPC_SYN; 1132 else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions) 1133 len = TCPOLEN_MPTCP_MPC_SYNACK; 1134 else if (opts->ext_copy.data_len) 1135 len = TCPOLEN_MPTCP_MPC_ACK_DATA; 1136 else 1137 len = TCPOLEN_MPTCP_MPC_ACK; 1138 1139 *ptr++ = mptcp_option(MPTCPOPT_MP_CAPABLE, len, 1140 MPTCP_SUPPORTED_VERSION, 1141 MPTCP_CAP_HMAC_SHA256); 1142 1143 if (!((OPTION_MPTCP_MPC_SYNACK | OPTION_MPTCP_MPC_ACK) & 1144 opts->suboptions)) 1145 goto mp_capable_done; 1146 1147 put_unaligned_be64(opts->sndr_key, ptr); 1148 ptr += 2; 1149 if (!((OPTION_MPTCP_MPC_ACK) & opts->suboptions)) 1150 goto mp_capable_done; 1151 1152 put_unaligned_be64(opts->rcvr_key, ptr); 1153 ptr += 2; 1154 if (!opts->ext_copy.data_len) 1155 goto mp_capable_done; 1156 1157 put_unaligned_be32(opts->ext_copy.data_len << 16 | 1158 TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); 1159 ptr += 1; 1160 } 1161 1162 mp_capable_done: 1163 if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) { 1164 u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE; 1165 u8 echo = MPTCP_ADDR_ECHO; 1166 1167 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 1168 if (opts->addr.family == AF_INET6) 1169 len = TCPOLEN_MPTCP_ADD_ADDR6_BASE; 1170 #endif 1171 1172 if (opts->addr.port) 1173 len += TCPOLEN_MPTCP_PORT_LEN; 1174 1175 if (opts->ahmac) { 1176 len += sizeof(opts->ahmac); 1177 echo = 0; 1178 } 1179 1180 *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR, 1181 len, echo, opts->addr.id); 1182 if (opts->addr.family == AF_INET) { 1183 memcpy((u8 *)ptr, (u8 *)&opts->addr.addr.s_addr, 4); 1184 ptr += 1; 1185 } 1186 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 1187 else if (opts->addr.family == AF_INET6) { 1188 memcpy((u8 *)ptr, opts->addr.addr6.s6_addr, 16); 1189 ptr += 4; 1190 } 1191 #endif 1192 1193 if (!opts->addr.port) { 1194 if (opts->ahmac) { 1195 put_unaligned_be64(opts->ahmac, ptr); 1196 ptr += 2; 1197 } 1198 } else { 1199 u16 port = ntohs(opts->addr.port); 1200 1201 if (opts->ahmac) { 1202 u8 *bptr = (u8 *)ptr; 1203 1204 put_unaligned_be16(port, bptr); 1205 bptr += 2; 1206 put_unaligned_be64(opts->ahmac, bptr); 1207 bptr += 8; 1208 put_unaligned_be16(TCPOPT_NOP << 8 | 1209 TCPOPT_NOP, bptr); 1210 1211 ptr += 3; 1212 } else { 1213 put_unaligned_be32(port << 16 | 1214 TCPOPT_NOP << 8 | 1215 TCPOPT_NOP, ptr); 1216 ptr += 1; 1217 } 1218 } 1219 } 1220 1221 if (OPTION_MPTCP_RM_ADDR & opts->suboptions) { 1222 u8 i = 1; 1223 1224 *ptr++ = mptcp_option(MPTCPOPT_RM_ADDR, 1225 TCPOLEN_MPTCP_RM_ADDR_BASE + opts->rm_list.nr, 1226 0, opts->rm_list.ids[0]); 1227 1228 while (i < opts->rm_list.nr) { 1229 u8 id1, id2, id3, id4; 1230 1231 id1 = opts->rm_list.ids[i]; 1232 id2 = i + 1 < opts->rm_list.nr ? opts->rm_list.ids[i + 1] : TCPOPT_NOP; 1233 id3 = i + 2 < opts->rm_list.nr ? opts->rm_list.ids[i + 2] : TCPOPT_NOP; 1234 id4 = i + 3 < opts->rm_list.nr ? opts->rm_list.ids[i + 3] : TCPOPT_NOP; 1235 put_unaligned_be32(id1 << 24 | id2 << 16 | id3 << 8 | id4, ptr); 1236 ptr += 1; 1237 i += 4; 1238 } 1239 } 1240 1241 if (OPTION_MPTCP_PRIO & opts->suboptions) { 1242 const struct sock *ssk = (const struct sock *)tp; 1243 struct mptcp_subflow_context *subflow; 1244 1245 subflow = mptcp_subflow_ctx(ssk); 1246 subflow->send_mp_prio = 0; 1247 1248 *ptr++ = mptcp_option(MPTCPOPT_MP_PRIO, 1249 TCPOLEN_MPTCP_PRIO, 1250 opts->backup, TCPOPT_NOP); 1251 } 1252 1253 if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) { 1254 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, 1255 TCPOLEN_MPTCP_MPJ_SYN, 1256 opts->backup, opts->join_id); 1257 put_unaligned_be32(opts->token, ptr); 1258 ptr += 1; 1259 put_unaligned_be32(opts->nonce, ptr); 1260 ptr += 1; 1261 } 1262 1263 if (OPTION_MPTCP_MPJ_SYNACK & opts->suboptions) { 1264 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, 1265 TCPOLEN_MPTCP_MPJ_SYNACK, 1266 opts->backup, opts->join_id); 1267 put_unaligned_be64(opts->thmac, ptr); 1268 ptr += 2; 1269 put_unaligned_be32(opts->nonce, ptr); 1270 ptr += 1; 1271 } 1272 1273 if (OPTION_MPTCP_MPJ_ACK & opts->suboptions) { 1274 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, 1275 TCPOLEN_MPTCP_MPJ_ACK, 0, 0); 1276 memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN); 1277 ptr += 5; 1278 } 1279 1280 if (OPTION_MPTCP_RST & opts->suboptions) 1281 *ptr++ = mptcp_option(MPTCPOPT_RST, 1282 TCPOLEN_MPTCP_RST, 1283 opts->reset_transient, 1284 opts->reset_reason); 1285 1286 if (opts->ext_copy.use_ack || opts->ext_copy.use_map) { 1287 struct mptcp_ext *mpext = &opts->ext_copy; 1288 u8 len = TCPOLEN_MPTCP_DSS_BASE; 1289 u8 flags = 0; 1290 1291 if (mpext->use_ack) { 1292 flags = MPTCP_DSS_HAS_ACK; 1293 if (mpext->ack64) { 1294 len += TCPOLEN_MPTCP_DSS_ACK64; 1295 flags |= MPTCP_DSS_ACK64; 1296 } else { 1297 len += TCPOLEN_MPTCP_DSS_ACK32; 1298 } 1299 } 1300 1301 if (mpext->use_map) { 1302 len += TCPOLEN_MPTCP_DSS_MAP64; 1303 1304 /* Use only 64-bit mapping flags for now, add 1305 * support for optional 32-bit mappings later. 1306 */ 1307 flags |= MPTCP_DSS_HAS_MAP | MPTCP_DSS_DSN64; 1308 if (mpext->data_fin) 1309 flags |= MPTCP_DSS_DATA_FIN; 1310 } 1311 1312 *ptr++ = mptcp_option(MPTCPOPT_DSS, len, 0, flags); 1313 1314 if (mpext->use_ack) { 1315 if (mpext->ack64) { 1316 put_unaligned_be64(mpext->data_ack, ptr); 1317 ptr += 2; 1318 } else { 1319 put_unaligned_be32(mpext->data_ack32, ptr); 1320 ptr += 1; 1321 } 1322 } 1323 1324 if (mpext->use_map) { 1325 put_unaligned_be64(mpext->data_seq, ptr); 1326 ptr += 2; 1327 put_unaligned_be32(mpext->subflow_seq, ptr); 1328 ptr += 1; 1329 put_unaligned_be32(mpext->data_len << 16 | 1330 TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); 1331 } 1332 } 1333 1334 if (tp) 1335 mptcp_set_rwin(tp); 1336 } 1337 1338 __be32 mptcp_get_reset_option(const struct sk_buff *skb) 1339 { 1340 const struct mptcp_ext *ext = mptcp_get_ext(skb); 1341 u8 flags, reason; 1342 1343 if (ext) { 1344 flags = ext->reset_transient; 1345 reason = ext->reset_reason; 1346 1347 return mptcp_option(MPTCPOPT_RST, TCPOLEN_MPTCP_RST, 1348 flags, reason); 1349 } 1350 1351 return htonl(0u); 1352 } 1353 EXPORT_SYMBOL_GPL(mptcp_get_reset_option); 1354