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 static bool mptcp_cap_flag_sha256(u8 flags) 17 { 18 return (flags & MPTCP_CAP_FLAG_MASK) == MPTCP_CAP_HMAC_SHA256; 19 } 20 21 static void mptcp_parse_option(const struct sk_buff *skb, 22 const unsigned char *ptr, int opsize, 23 struct mptcp_options_received *mp_opt) 24 { 25 u8 subtype = *ptr >> 4; 26 int expected_opsize; 27 u8 version; 28 u8 flags; 29 30 switch (subtype) { 31 case MPTCPOPT_MP_CAPABLE: 32 /* strict size checking */ 33 if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) { 34 if (skb->len > tcp_hdr(skb)->doff << 2) 35 expected_opsize = TCPOLEN_MPTCP_MPC_ACK_DATA; 36 else 37 expected_opsize = TCPOLEN_MPTCP_MPC_ACK; 38 } else { 39 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_ACK) 40 expected_opsize = TCPOLEN_MPTCP_MPC_SYNACK; 41 else 42 expected_opsize = TCPOLEN_MPTCP_MPC_SYN; 43 } 44 if (opsize != expected_opsize) 45 break; 46 47 /* try to be gentle vs future versions on the initial syn */ 48 version = *ptr++ & MPTCP_VERSION_MASK; 49 if (opsize != TCPOLEN_MPTCP_MPC_SYN) { 50 if (version != MPTCP_SUPPORTED_VERSION) 51 break; 52 } else if (version < MPTCP_SUPPORTED_VERSION) { 53 break; 54 } 55 56 flags = *ptr++; 57 if (!mptcp_cap_flag_sha256(flags) || 58 (flags & MPTCP_CAP_EXTENSIBILITY)) 59 break; 60 61 /* RFC 6824, Section 3.1: 62 * "For the Checksum Required bit (labeled "A"), if either 63 * host requires the use of checksums, checksums MUST be used. 64 * In other words, the only way for checksums not to be used 65 * is if both hosts in their SYNs set A=0." 66 * 67 * Section 3.3.0: 68 * "If a checksum is not present when its use has been 69 * negotiated, the receiver MUST close the subflow with a RST as 70 * it is considered broken." 71 * 72 * We don't implement DSS checksum - fall back to TCP. 73 */ 74 if (flags & MPTCP_CAP_CHECKSUM_REQD) 75 break; 76 77 mp_opt->mp_capable = 1; 78 if (opsize >= TCPOLEN_MPTCP_MPC_SYNACK) { 79 mp_opt->sndr_key = get_unaligned_be64(ptr); 80 ptr += 8; 81 } 82 if (opsize >= TCPOLEN_MPTCP_MPC_ACK) { 83 mp_opt->rcvr_key = get_unaligned_be64(ptr); 84 ptr += 8; 85 } 86 if (opsize == TCPOLEN_MPTCP_MPC_ACK_DATA) { 87 /* Section 3.1.: 88 * "the data parameters in a MP_CAPABLE are semantically 89 * equivalent to those in a DSS option and can be used 90 * interchangeably." 91 */ 92 mp_opt->dss = 1; 93 mp_opt->use_map = 1; 94 mp_opt->mpc_map = 1; 95 mp_opt->data_len = get_unaligned_be16(ptr); 96 ptr += 2; 97 } 98 pr_debug("MP_CAPABLE version=%x, flags=%x, optlen=%d sndr=%llu, rcvr=%llu len=%d", 99 version, flags, opsize, mp_opt->sndr_key, 100 mp_opt->rcvr_key, mp_opt->data_len); 101 break; 102 103 case MPTCPOPT_MP_JOIN: 104 mp_opt->mp_join = 1; 105 if (opsize == TCPOLEN_MPTCP_MPJ_SYN) { 106 mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP; 107 mp_opt->join_id = *ptr++; 108 mp_opt->token = get_unaligned_be32(ptr); 109 ptr += 4; 110 mp_opt->nonce = get_unaligned_be32(ptr); 111 ptr += 4; 112 pr_debug("MP_JOIN bkup=%u, id=%u, token=%u, nonce=%u", 113 mp_opt->backup, mp_opt->join_id, 114 mp_opt->token, mp_opt->nonce); 115 } else if (opsize == TCPOLEN_MPTCP_MPJ_SYNACK) { 116 mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP; 117 mp_opt->join_id = *ptr++; 118 mp_opt->thmac = get_unaligned_be64(ptr); 119 ptr += 8; 120 mp_opt->nonce = get_unaligned_be32(ptr); 121 ptr += 4; 122 pr_debug("MP_JOIN bkup=%u, id=%u, thmac=%llu, nonce=%u", 123 mp_opt->backup, mp_opt->join_id, 124 mp_opt->thmac, mp_opt->nonce); 125 } else if (opsize == TCPOLEN_MPTCP_MPJ_ACK) { 126 ptr += 2; 127 memcpy(mp_opt->hmac, ptr, MPTCPOPT_HMAC_LEN); 128 pr_debug("MP_JOIN hmac"); 129 } else { 130 pr_warn("MP_JOIN bad option size"); 131 mp_opt->mp_join = 0; 132 } 133 break; 134 135 case MPTCPOPT_DSS: 136 pr_debug("DSS"); 137 ptr++; 138 139 /* we must clear 'mpc_map' be able to detect MP_CAPABLE 140 * map vs DSS map in mptcp_incoming_options(), and reconstruct 141 * map info accordingly 142 */ 143 mp_opt->mpc_map = 0; 144 flags = (*ptr++) & MPTCP_DSS_FLAG_MASK; 145 mp_opt->data_fin = (flags & MPTCP_DSS_DATA_FIN) != 0; 146 mp_opt->dsn64 = (flags & MPTCP_DSS_DSN64) != 0; 147 mp_opt->use_map = (flags & MPTCP_DSS_HAS_MAP) != 0; 148 mp_opt->ack64 = (flags & MPTCP_DSS_ACK64) != 0; 149 mp_opt->use_ack = (flags & MPTCP_DSS_HAS_ACK); 150 151 pr_debug("data_fin=%d dsn64=%d use_map=%d ack64=%d use_ack=%d", 152 mp_opt->data_fin, mp_opt->dsn64, 153 mp_opt->use_map, mp_opt->ack64, 154 mp_opt->use_ack); 155 156 expected_opsize = TCPOLEN_MPTCP_DSS_BASE; 157 158 if (mp_opt->use_ack) { 159 if (mp_opt->ack64) 160 expected_opsize += TCPOLEN_MPTCP_DSS_ACK64; 161 else 162 expected_opsize += TCPOLEN_MPTCP_DSS_ACK32; 163 } 164 165 if (mp_opt->use_map) { 166 if (mp_opt->dsn64) 167 expected_opsize += TCPOLEN_MPTCP_DSS_MAP64; 168 else 169 expected_opsize += TCPOLEN_MPTCP_DSS_MAP32; 170 } 171 172 /* RFC 6824, Section 3.3: 173 * If a checksum is present, but its use had 174 * not been negotiated in the MP_CAPABLE handshake, 175 * the checksum field MUST be ignored. 176 */ 177 if (opsize != expected_opsize && 178 opsize != expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM) 179 break; 180 181 mp_opt->dss = 1; 182 183 if (mp_opt->use_ack) { 184 if (mp_opt->ack64) { 185 mp_opt->data_ack = get_unaligned_be64(ptr); 186 ptr += 8; 187 } else { 188 mp_opt->data_ack = get_unaligned_be32(ptr); 189 ptr += 4; 190 } 191 192 pr_debug("data_ack=%llu", mp_opt->data_ack); 193 } 194 195 if (mp_opt->use_map) { 196 if (mp_opt->dsn64) { 197 mp_opt->data_seq = get_unaligned_be64(ptr); 198 ptr += 8; 199 } else { 200 mp_opt->data_seq = get_unaligned_be32(ptr); 201 ptr += 4; 202 } 203 204 mp_opt->subflow_seq = get_unaligned_be32(ptr); 205 ptr += 4; 206 207 mp_opt->data_len = get_unaligned_be16(ptr); 208 ptr += 2; 209 210 pr_debug("data_seq=%llu subflow_seq=%u data_len=%u", 211 mp_opt->data_seq, mp_opt->subflow_seq, 212 mp_opt->data_len); 213 } 214 215 break; 216 217 case MPTCPOPT_ADD_ADDR: 218 mp_opt->echo = (*ptr++) & MPTCP_ADDR_ECHO; 219 if (!mp_opt->echo) { 220 if (opsize == TCPOLEN_MPTCP_ADD_ADDR || 221 opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT) 222 mp_opt->family = MPTCP_ADDR_IPVERSION_4; 223 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 224 else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6 || 225 opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT) 226 mp_opt->family = MPTCP_ADDR_IPVERSION_6; 227 #endif 228 else 229 break; 230 } else { 231 if (opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE || 232 opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) 233 mp_opt->family = MPTCP_ADDR_IPVERSION_4; 234 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 235 else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE || 236 opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) 237 mp_opt->family = MPTCP_ADDR_IPVERSION_6; 238 #endif 239 else 240 break; 241 } 242 243 mp_opt->add_addr = 1; 244 mp_opt->addr_id = *ptr++; 245 if (mp_opt->family == MPTCP_ADDR_IPVERSION_4) { 246 memcpy((u8 *)&mp_opt->addr.s_addr, (u8 *)ptr, 4); 247 ptr += 4; 248 if (opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT || 249 opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) { 250 mp_opt->port = get_unaligned_be16(ptr); 251 ptr += 2; 252 } 253 } 254 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 255 else { 256 memcpy(mp_opt->addr6.s6_addr, (u8 *)ptr, 16); 257 ptr += 16; 258 if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT || 259 opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) { 260 mp_opt->port = get_unaligned_be16(ptr); 261 ptr += 2; 262 } 263 } 264 #endif 265 if (!mp_opt->echo) { 266 mp_opt->ahmac = get_unaligned_be64(ptr); 267 ptr += 8; 268 } 269 pr_debug("ADD_ADDR%s: id=%d, ahmac=%llu, echo=%d, port=%d", 270 (mp_opt->family == MPTCP_ADDR_IPVERSION_6) ? "6" : "", 271 mp_opt->addr_id, mp_opt->ahmac, mp_opt->echo, mp_opt->port); 272 break; 273 274 case MPTCPOPT_RM_ADDR: 275 if (opsize != TCPOLEN_MPTCP_RM_ADDR_BASE) 276 break; 277 278 ptr++; 279 280 mp_opt->rm_addr = 1; 281 mp_opt->rm_id = *ptr++; 282 pr_debug("RM_ADDR: id=%d", mp_opt->rm_id); 283 break; 284 285 case MPTCPOPT_MP_FASTCLOSE: 286 if (opsize != TCPOLEN_MPTCP_FASTCLOSE) 287 break; 288 289 ptr += 2; 290 mp_opt->rcvr_key = get_unaligned_be64(ptr); 291 ptr += 8; 292 mp_opt->fastclose = 1; 293 break; 294 295 default: 296 break; 297 } 298 } 299 300 void mptcp_get_options(const struct sk_buff *skb, 301 struct mptcp_options_received *mp_opt) 302 { 303 const struct tcphdr *th = tcp_hdr(skb); 304 const unsigned char *ptr; 305 int length; 306 307 /* initialize option status */ 308 mp_opt->mp_capable = 0; 309 mp_opt->mp_join = 0; 310 mp_opt->add_addr = 0; 311 mp_opt->ahmac = 0; 312 mp_opt->fastclose = 0; 313 mp_opt->port = 0; 314 mp_opt->rm_addr = 0; 315 mp_opt->dss = 0; 316 317 length = (th->doff * 4) - sizeof(struct tcphdr); 318 ptr = (const unsigned char *)(th + 1); 319 320 while (length > 0) { 321 int opcode = *ptr++; 322 int opsize; 323 324 switch (opcode) { 325 case TCPOPT_EOL: 326 return; 327 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */ 328 length--; 329 continue; 330 default: 331 opsize = *ptr++; 332 if (opsize < 2) /* "silly options" */ 333 return; 334 if (opsize > length) 335 return; /* don't parse partial options */ 336 if (opcode == TCPOPT_MPTCP) 337 mptcp_parse_option(skb, ptr, opsize, mp_opt); 338 ptr += opsize - 2; 339 length -= opsize; 340 } 341 } 342 } 343 344 bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb, 345 unsigned int *size, struct mptcp_out_options *opts) 346 { 347 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 348 349 /* we will use snd_isn to detect first pkt [re]transmission 350 * in mptcp_established_options_mp() 351 */ 352 subflow->snd_isn = TCP_SKB_CB(skb)->end_seq; 353 if (subflow->request_mptcp) { 354 opts->suboptions = OPTION_MPTCP_MPC_SYN; 355 *size = TCPOLEN_MPTCP_MPC_SYN; 356 return true; 357 } else if (subflow->request_join) { 358 pr_debug("remote_token=%u, nonce=%u", subflow->remote_token, 359 subflow->local_nonce); 360 opts->suboptions = OPTION_MPTCP_MPJ_SYN; 361 opts->join_id = subflow->local_id; 362 opts->token = subflow->remote_token; 363 opts->nonce = subflow->local_nonce; 364 opts->backup = subflow->request_bkup; 365 *size = TCPOLEN_MPTCP_MPJ_SYN; 366 return true; 367 } 368 return false; 369 } 370 371 /* MP_JOIN client subflow must wait for 4th ack before sending any data: 372 * TCP can't schedule delack timer before the subflow is fully established. 373 * MPTCP uses the delack timer to do 3rd ack retransmissions 374 */ 375 static void schedule_3rdack_retransmission(struct sock *sk) 376 { 377 struct inet_connection_sock *icsk = inet_csk(sk); 378 struct tcp_sock *tp = tcp_sk(sk); 379 unsigned long timeout; 380 381 /* reschedule with a timeout above RTT, as we must look only for drop */ 382 if (tp->srtt_us) 383 timeout = tp->srtt_us << 1; 384 else 385 timeout = TCP_TIMEOUT_INIT; 386 387 WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER); 388 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; 389 icsk->icsk_ack.timeout = timeout; 390 sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout); 391 } 392 393 static void clear_3rdack_retransmission(struct sock *sk) 394 { 395 struct inet_connection_sock *icsk = inet_csk(sk); 396 397 sk_stop_timer(sk, &icsk->icsk_delack_timer); 398 icsk->icsk_ack.timeout = 0; 399 icsk->icsk_ack.ato = 0; 400 icsk->icsk_ack.pending &= ~(ICSK_ACK_SCHED | ICSK_ACK_TIMER); 401 } 402 403 static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb, 404 unsigned int *size, 405 unsigned int remaining, 406 struct mptcp_out_options *opts) 407 { 408 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 409 struct mptcp_ext *mpext; 410 unsigned int data_len; 411 412 /* When skb is not available, we better over-estimate the emitted 413 * options len. A full DSS option (28 bytes) is longer than 414 * TCPOLEN_MPTCP_MPC_ACK_DATA(22) or TCPOLEN_MPTCP_MPJ_ACK(24), so 415 * tell the caller to defer the estimate to 416 * mptcp_established_options_dss(), which will reserve enough space. 417 */ 418 if (!skb) 419 return false; 420 421 /* MPC/MPJ needed only on 3rd ack packet */ 422 if (subflow->fully_established || 423 subflow->snd_isn != TCP_SKB_CB(skb)->seq) 424 return false; 425 426 if (subflow->mp_capable) { 427 mpext = mptcp_get_ext(skb); 428 data_len = mpext ? mpext->data_len : 0; 429 430 /* we will check ext_copy.data_len in mptcp_write_options() to 431 * discriminate between TCPOLEN_MPTCP_MPC_ACK_DATA and 432 * TCPOLEN_MPTCP_MPC_ACK 433 */ 434 opts->ext_copy.data_len = data_len; 435 opts->suboptions = OPTION_MPTCP_MPC_ACK; 436 opts->sndr_key = subflow->local_key; 437 opts->rcvr_key = subflow->remote_key; 438 439 /* Section 3.1. 440 * The MP_CAPABLE option is carried on the SYN, SYN/ACK, and ACK 441 * packets that start the first subflow of an MPTCP connection, 442 * as well as the first packet that carries data 443 */ 444 if (data_len > 0) 445 *size = ALIGN(TCPOLEN_MPTCP_MPC_ACK_DATA, 4); 446 else 447 *size = TCPOLEN_MPTCP_MPC_ACK; 448 449 pr_debug("subflow=%p, local_key=%llu, remote_key=%llu map_len=%d", 450 subflow, subflow->local_key, subflow->remote_key, 451 data_len); 452 453 return true; 454 } else if (subflow->mp_join) { 455 opts->suboptions = OPTION_MPTCP_MPJ_ACK; 456 memcpy(opts->hmac, subflow->hmac, MPTCPOPT_HMAC_LEN); 457 *size = TCPOLEN_MPTCP_MPJ_ACK; 458 pr_debug("subflow=%p", subflow); 459 460 schedule_3rdack_retransmission(sk); 461 return true; 462 } 463 return false; 464 } 465 466 static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow, 467 struct sk_buff *skb, struct mptcp_ext *ext) 468 { 469 /* The write_seq value has already been incremented, so the actual 470 * sequence number for the DATA_FIN is one less. 471 */ 472 u64 data_fin_tx_seq = READ_ONCE(mptcp_sk(subflow->conn)->write_seq) - 1; 473 474 if (!ext->use_map || !skb->len) { 475 /* RFC6824 requires a DSS mapping with specific values 476 * if DATA_FIN is set but no data payload is mapped 477 */ 478 ext->data_fin = 1; 479 ext->use_map = 1; 480 ext->dsn64 = 1; 481 ext->data_seq = data_fin_tx_seq; 482 ext->subflow_seq = 0; 483 ext->data_len = 1; 484 } else if (ext->data_seq + ext->data_len == data_fin_tx_seq) { 485 /* If there's an existing DSS mapping and it is the 486 * final mapping, DATA_FIN consumes 1 additional byte of 487 * mapping space. 488 */ 489 ext->data_fin = 1; 490 ext->data_len++; 491 } 492 } 493 494 static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb, 495 unsigned int *size, 496 unsigned int remaining, 497 struct mptcp_out_options *opts) 498 { 499 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 500 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 501 unsigned int dss_size = 0; 502 u64 snd_data_fin_enable; 503 struct mptcp_ext *mpext; 504 unsigned int ack_size; 505 bool ret = false; 506 507 mpext = skb ? mptcp_get_ext(skb) : NULL; 508 snd_data_fin_enable = mptcp_data_fin_enabled(msk); 509 510 if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) { 511 unsigned int map_size; 512 513 map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64; 514 515 remaining -= map_size; 516 dss_size = map_size; 517 if (mpext) 518 opts->ext_copy = *mpext; 519 520 if (skb && snd_data_fin_enable) 521 mptcp_write_data_fin(subflow, skb, &opts->ext_copy); 522 ret = true; 523 } 524 525 /* passive sockets msk will set the 'can_ack' after accept(), even 526 * if the first subflow may have the already the remote key handy 527 */ 528 opts->ext_copy.use_ack = 0; 529 if (!READ_ONCE(msk->can_ack)) { 530 *size = ALIGN(dss_size, 4); 531 return ret; 532 } 533 534 if (READ_ONCE(msk->use_64bit_ack)) { 535 ack_size = TCPOLEN_MPTCP_DSS_ACK64; 536 opts->ext_copy.data_ack = READ_ONCE(msk->ack_seq); 537 opts->ext_copy.ack64 = 1; 538 } else { 539 ack_size = TCPOLEN_MPTCP_DSS_ACK32; 540 opts->ext_copy.data_ack32 = (uint32_t)READ_ONCE(msk->ack_seq); 541 opts->ext_copy.ack64 = 0; 542 } 543 opts->ext_copy.use_ack = 1; 544 WRITE_ONCE(msk->old_wspace, __mptcp_space((struct sock *)msk)); 545 546 /* Add kind/length/subtype/flag overhead if mapping is not populated */ 547 if (dss_size == 0) 548 ack_size += TCPOLEN_MPTCP_DSS_BASE; 549 550 dss_size += ack_size; 551 552 *size = ALIGN(dss_size, 4); 553 return true; 554 } 555 556 static u64 add_addr_generate_hmac(u64 key1, u64 key2, u8 addr_id, 557 struct in_addr *addr) 558 { 559 u8 hmac[SHA256_DIGEST_SIZE]; 560 u8 msg[7]; 561 562 msg[0] = addr_id; 563 memcpy(&msg[1], &addr->s_addr, 4); 564 msg[5] = 0; 565 msg[6] = 0; 566 567 mptcp_crypto_hmac_sha(key1, key2, msg, 7, hmac); 568 569 return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]); 570 } 571 572 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 573 static u64 add_addr6_generate_hmac(u64 key1, u64 key2, u8 addr_id, 574 struct in6_addr *addr) 575 { 576 u8 hmac[SHA256_DIGEST_SIZE]; 577 u8 msg[19]; 578 579 msg[0] = addr_id; 580 memcpy(&msg[1], &addr->s6_addr, 16); 581 msg[17] = 0; 582 msg[18] = 0; 583 584 mptcp_crypto_hmac_sha(key1, key2, msg, 19, hmac); 585 586 return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]); 587 } 588 #endif 589 590 static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *skb, 591 unsigned int *size, 592 unsigned int remaining, 593 struct mptcp_out_options *opts) 594 { 595 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 596 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 597 bool drop_other_suboptions = false; 598 unsigned int opt_size = *size; 599 struct mptcp_addr_info saddr; 600 bool echo; 601 bool port; 602 int len; 603 604 if ((mptcp_pm_should_add_signal_ipv6(msk) || 605 mptcp_pm_should_add_signal_port(msk)) && 606 skb && skb_is_tcp_pure_ack(skb)) { 607 pr_debug("drop other suboptions"); 608 opts->suboptions = 0; 609 remaining += opt_size; 610 drop_other_suboptions = true; 611 } 612 613 if (!mptcp_pm_should_add_signal(msk) || 614 !(mptcp_pm_add_addr_signal(msk, remaining, &saddr, &echo, &port))) 615 return false; 616 617 len = mptcp_add_addr_len(saddr.family, echo, port); 618 if (remaining < len) 619 return false; 620 621 *size = len; 622 if (drop_other_suboptions) 623 *size -= opt_size; 624 opts->addr_id = saddr.id; 625 if (port) 626 opts->port = ntohs(saddr.port); 627 if (saddr.family == AF_INET) { 628 opts->suboptions |= OPTION_MPTCP_ADD_ADDR; 629 opts->addr = saddr.addr; 630 if (!echo) { 631 opts->ahmac = add_addr_generate_hmac(msk->local_key, 632 msk->remote_key, 633 opts->addr_id, 634 &opts->addr); 635 } 636 } 637 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 638 else if (saddr.family == AF_INET6) { 639 opts->suboptions |= OPTION_MPTCP_ADD_ADDR6; 640 opts->addr6 = saddr.addr6; 641 if (!echo) { 642 opts->ahmac = add_addr6_generate_hmac(msk->local_key, 643 msk->remote_key, 644 opts->addr_id, 645 &opts->addr6); 646 } 647 } 648 #endif 649 pr_debug("addr_id=%d, ahmac=%llu, echo=%d, port=%d", 650 opts->addr_id, opts->ahmac, echo, opts->port); 651 652 return true; 653 } 654 655 static bool mptcp_established_options_rm_addr(struct sock *sk, 656 unsigned int *size, 657 unsigned int remaining, 658 struct mptcp_out_options *opts) 659 { 660 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 661 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 662 u8 rm_id; 663 664 if (!mptcp_pm_should_rm_signal(msk) || 665 !(mptcp_pm_rm_addr_signal(msk, remaining, &rm_id))) 666 return false; 667 668 if (remaining < TCPOLEN_MPTCP_RM_ADDR_BASE) 669 return false; 670 671 *size = TCPOLEN_MPTCP_RM_ADDR_BASE; 672 opts->suboptions |= OPTION_MPTCP_RM_ADDR; 673 opts->rm_id = rm_id; 674 675 pr_debug("rm_id=%d", opts->rm_id); 676 677 return true; 678 } 679 680 bool mptcp_established_options(struct sock *sk, struct sk_buff *skb, 681 unsigned int *size, unsigned int remaining, 682 struct mptcp_out_options *opts) 683 { 684 unsigned int opt_size = 0; 685 bool ret = false; 686 687 opts->suboptions = 0; 688 689 if (unlikely(mptcp_check_fallback(sk))) 690 return false; 691 692 /* prevent adding of any MPTCP related options on reset packet 693 * until we support MP_TCPRST/MP_FASTCLOSE 694 */ 695 if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) 696 return false; 697 698 if (mptcp_established_options_mp(sk, skb, &opt_size, remaining, opts)) 699 ret = true; 700 else if (mptcp_established_options_dss(sk, skb, &opt_size, remaining, 701 opts)) 702 ret = true; 703 704 /* we reserved enough space for the above options, and exceeding the 705 * TCP option space would be fatal 706 */ 707 if (WARN_ON_ONCE(opt_size > remaining)) 708 return false; 709 710 *size += opt_size; 711 remaining -= opt_size; 712 if (mptcp_established_options_add_addr(sk, skb, &opt_size, remaining, opts)) { 713 *size += opt_size; 714 remaining -= opt_size; 715 ret = true; 716 } else if (mptcp_established_options_rm_addr(sk, &opt_size, remaining, opts)) { 717 *size += opt_size; 718 remaining -= opt_size; 719 ret = true; 720 } 721 722 return ret; 723 } 724 725 bool mptcp_synack_options(const struct request_sock *req, unsigned int *size, 726 struct mptcp_out_options *opts) 727 { 728 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); 729 730 if (subflow_req->mp_capable) { 731 opts->suboptions = OPTION_MPTCP_MPC_SYNACK; 732 opts->sndr_key = subflow_req->local_key; 733 *size = TCPOLEN_MPTCP_MPC_SYNACK; 734 pr_debug("subflow_req=%p, local_key=%llu", 735 subflow_req, subflow_req->local_key); 736 return true; 737 } else if (subflow_req->mp_join) { 738 opts->suboptions = OPTION_MPTCP_MPJ_SYNACK; 739 opts->backup = subflow_req->backup; 740 opts->join_id = subflow_req->local_id; 741 opts->thmac = subflow_req->thmac; 742 opts->nonce = subflow_req->local_nonce; 743 pr_debug("req=%p, bkup=%u, id=%u, thmac=%llu, nonce=%u", 744 subflow_req, opts->backup, opts->join_id, 745 opts->thmac, opts->nonce); 746 *size = TCPOLEN_MPTCP_MPJ_SYNACK; 747 return true; 748 } 749 return false; 750 } 751 752 static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk, 753 struct mptcp_subflow_context *subflow, 754 struct sk_buff *skb, 755 struct mptcp_options_received *mp_opt) 756 { 757 /* here we can process OoO, in-window pkts, only in-sequence 4th ack 758 * will make the subflow fully established 759 */ 760 if (likely(subflow->fully_established)) { 761 /* on passive sockets, check for 3rd ack retransmission 762 * note that msk is always set by subflow_syn_recv_sock() 763 * for mp_join subflows 764 */ 765 if (TCP_SKB_CB(skb)->seq == subflow->ssn_offset + 1 && 766 TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq && 767 subflow->mp_join && mp_opt->mp_join && 768 READ_ONCE(msk->pm.server_side)) 769 tcp_send_ack(ssk); 770 goto fully_established; 771 } 772 773 /* we must process OoO packets before the first subflow is fully 774 * established. OoO packets are instead a protocol violation 775 * for MP_JOIN subflows as the peer must not send any data 776 * before receiving the forth ack - cfr. RFC 8684 section 3.2. 777 */ 778 if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) { 779 if (subflow->mp_join) 780 goto reset; 781 return subflow->mp_capable; 782 } 783 784 if (mp_opt->dss && mp_opt->use_ack) { 785 /* subflows are fully established as soon as we get any 786 * additional ack. 787 */ 788 subflow->fully_established = 1; 789 WRITE_ONCE(msk->fully_established, true); 790 goto fully_established; 791 } 792 793 if (mp_opt->add_addr) { 794 WRITE_ONCE(msk->fully_established, true); 795 return true; 796 } 797 798 /* If the first established packet does not contain MP_CAPABLE + data 799 * then fallback to TCP. Fallback scenarios requires a reset for 800 * MP_JOIN subflows. 801 */ 802 if (!mp_opt->mp_capable) { 803 if (subflow->mp_join) 804 goto reset; 805 subflow->mp_capable = 0; 806 pr_fallback(msk); 807 __mptcp_do_fallback(msk); 808 return false; 809 } 810 811 if (unlikely(!READ_ONCE(msk->pm.server_side))) 812 pr_warn_once("bogus mpc option on established client sk"); 813 mptcp_subflow_fully_established(subflow, mp_opt); 814 815 fully_established: 816 /* if the subflow is not already linked into the conn_list, we can't 817 * notify the PM: this subflow is still on the listener queue 818 * and the PM possibly acquiring the subflow lock could race with 819 * the listener close 820 */ 821 if (likely(subflow->pm_notified) || list_empty(&subflow->node)) 822 return true; 823 824 subflow->pm_notified = 1; 825 if (subflow->mp_join) { 826 clear_3rdack_retransmission(ssk); 827 mptcp_pm_subflow_established(msk, subflow); 828 } else { 829 mptcp_pm_fully_established(msk); 830 } 831 return true; 832 833 reset: 834 mptcp_subflow_reset(ssk); 835 return false; 836 } 837 838 static u64 expand_ack(u64 old_ack, u64 cur_ack, bool use_64bit) 839 { 840 u32 old_ack32, cur_ack32; 841 842 if (use_64bit) 843 return cur_ack; 844 845 old_ack32 = (u32)old_ack; 846 cur_ack32 = (u32)cur_ack; 847 cur_ack = (old_ack & GENMASK_ULL(63, 32)) + cur_ack32; 848 if (unlikely(before(cur_ack32, old_ack32))) 849 return cur_ack + (1LL << 32); 850 return cur_ack; 851 } 852 853 static void ack_update_msk(struct mptcp_sock *msk, 854 struct sock *ssk, 855 struct mptcp_options_received *mp_opt) 856 { 857 u64 new_wnd_end, new_snd_una, snd_nxt = READ_ONCE(msk->snd_nxt); 858 struct sock *sk = (struct sock *)msk; 859 u64 old_snd_una; 860 861 mptcp_data_lock(sk); 862 863 /* avoid ack expansion on update conflict, to reduce the risk of 864 * wrongly expanding to a future ack sequence number, which is way 865 * more dangerous than missing an ack 866 */ 867 old_snd_una = msk->snd_una; 868 new_snd_una = expand_ack(old_snd_una, mp_opt->data_ack, mp_opt->ack64); 869 870 /* ACK for data not even sent yet? Ignore. */ 871 if (after64(new_snd_una, snd_nxt)) 872 new_snd_una = old_snd_una; 873 874 new_wnd_end = new_snd_una + tcp_sk(ssk)->snd_wnd; 875 876 if (after64(new_wnd_end, msk->wnd_end)) { 877 msk->wnd_end = new_wnd_end; 878 __mptcp_wnd_updated(sk, ssk); 879 } 880 881 if (after64(new_snd_una, old_snd_una)) { 882 msk->snd_una = new_snd_una; 883 __mptcp_data_acked(sk); 884 } 885 mptcp_data_unlock(sk); 886 } 887 888 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit) 889 { 890 /* Skip if DATA_FIN was already received. 891 * If updating simultaneously with the recvmsg loop, values 892 * should match. If they mismatch, the peer is misbehaving and 893 * we will prefer the most recent information. 894 */ 895 if (READ_ONCE(msk->rcv_data_fin) || !READ_ONCE(msk->first)) 896 return false; 897 898 WRITE_ONCE(msk->rcv_data_fin_seq, 899 expand_ack(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit)); 900 WRITE_ONCE(msk->rcv_data_fin, 1); 901 902 return true; 903 } 904 905 static bool add_addr_hmac_valid(struct mptcp_sock *msk, 906 struct mptcp_options_received *mp_opt) 907 { 908 u64 hmac = 0; 909 910 if (mp_opt->echo) 911 return true; 912 913 if (mp_opt->family == MPTCP_ADDR_IPVERSION_4) 914 hmac = add_addr_generate_hmac(msk->remote_key, 915 msk->local_key, 916 mp_opt->addr_id, &mp_opt->addr); 917 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 918 else 919 hmac = add_addr6_generate_hmac(msk->remote_key, 920 msk->local_key, 921 mp_opt->addr_id, &mp_opt->addr6); 922 #endif 923 924 pr_debug("msk=%p, ahmac=%llu, mp_opt->ahmac=%llu\n", 925 msk, (unsigned long long)hmac, 926 (unsigned long long)mp_opt->ahmac); 927 928 return hmac == mp_opt->ahmac; 929 } 930 931 void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb) 932 { 933 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 934 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 935 struct mptcp_options_received mp_opt; 936 struct mptcp_ext *mpext; 937 938 if (__mptcp_check_fallback(msk)) { 939 /* Keep it simple and unconditionally trigger send data cleanup and 940 * pending queue spooling. We will need to acquire the data lock 941 * for more accurate checks, and once the lock is acquired, such 942 * helpers are cheap. 943 */ 944 mptcp_data_lock(subflow->conn); 945 if (mptcp_send_head(subflow->conn)) 946 __mptcp_wnd_updated(subflow->conn, sk); 947 __mptcp_data_acked(subflow->conn); 948 mptcp_data_unlock(subflow->conn); 949 return; 950 } 951 952 mptcp_get_options(skb, &mp_opt); 953 if (!check_fully_established(msk, sk, subflow, skb, &mp_opt)) 954 return; 955 956 if (mp_opt.fastclose && 957 msk->local_key == mp_opt.rcvr_key) { 958 WRITE_ONCE(msk->rcv_fastclose, true); 959 mptcp_schedule_work((struct sock *)msk); 960 } 961 962 if (mp_opt.add_addr && add_addr_hmac_valid(msk, &mp_opt)) { 963 struct mptcp_addr_info addr; 964 965 addr.port = htons(mp_opt.port); 966 addr.id = mp_opt.addr_id; 967 if (mp_opt.family == MPTCP_ADDR_IPVERSION_4) { 968 addr.family = AF_INET; 969 addr.addr = mp_opt.addr; 970 } 971 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 972 else if (mp_opt.family == MPTCP_ADDR_IPVERSION_6) { 973 addr.family = AF_INET6; 974 addr.addr6 = mp_opt.addr6; 975 } 976 #endif 977 if (!mp_opt.echo) { 978 mptcp_pm_add_addr_received(msk, &addr); 979 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR); 980 } else { 981 mptcp_pm_del_add_timer(msk, &addr); 982 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD); 983 } 984 mp_opt.add_addr = 0; 985 } 986 987 if (mp_opt.rm_addr) { 988 mptcp_pm_rm_addr_received(msk, mp_opt.rm_id); 989 mp_opt.rm_addr = 0; 990 } 991 992 if (!mp_opt.dss) 993 return; 994 995 /* we can't wait for recvmsg() to update the ack_seq, otherwise 996 * monodirectional flows will stuck 997 */ 998 if (mp_opt.use_ack) 999 ack_update_msk(msk, sk, &mp_opt); 1000 1001 /* Zero-data-length packets are dropped by the caller and not 1002 * propagated to the MPTCP layer, so the skb extension does not 1003 * need to be allocated or populated. DATA_FIN information, if 1004 * present, needs to be updated here before the skb is freed. 1005 */ 1006 if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) { 1007 if (mp_opt.data_fin && mp_opt.data_len == 1 && 1008 mptcp_update_rcv_data_fin(msk, mp_opt.data_seq, mp_opt.dsn64) && 1009 schedule_work(&msk->work)) 1010 sock_hold(subflow->conn); 1011 1012 return; 1013 } 1014 1015 mpext = skb_ext_add(skb, SKB_EXT_MPTCP); 1016 if (!mpext) 1017 return; 1018 1019 memset(mpext, 0, sizeof(*mpext)); 1020 1021 if (mp_opt.use_map) { 1022 if (mp_opt.mpc_map) { 1023 /* this is an MP_CAPABLE carrying MPTCP data 1024 * we know this map the first chunk of data 1025 */ 1026 mptcp_crypto_key_sha(subflow->remote_key, NULL, 1027 &mpext->data_seq); 1028 mpext->data_seq++; 1029 mpext->subflow_seq = 1; 1030 mpext->dsn64 = 1; 1031 mpext->mpc_map = 1; 1032 mpext->data_fin = 0; 1033 } else { 1034 mpext->data_seq = mp_opt.data_seq; 1035 mpext->subflow_seq = mp_opt.subflow_seq; 1036 mpext->dsn64 = mp_opt.dsn64; 1037 mpext->data_fin = mp_opt.data_fin; 1038 } 1039 mpext->data_len = mp_opt.data_len; 1040 mpext->use_map = 1; 1041 } 1042 } 1043 1044 static void mptcp_set_rwin(const struct tcp_sock *tp) 1045 { 1046 const struct sock *ssk = (const struct sock *)tp; 1047 const struct mptcp_subflow_context *subflow; 1048 struct mptcp_sock *msk; 1049 u64 ack_seq; 1050 1051 subflow = mptcp_subflow_ctx(ssk); 1052 msk = mptcp_sk(subflow->conn); 1053 1054 ack_seq = READ_ONCE(msk->ack_seq) + tp->rcv_wnd; 1055 1056 if (after64(ack_seq, READ_ONCE(msk->rcv_wnd_sent))) 1057 WRITE_ONCE(msk->rcv_wnd_sent, ack_seq); 1058 } 1059 1060 void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp, 1061 struct mptcp_out_options *opts) 1062 { 1063 if ((OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK | 1064 OPTION_MPTCP_MPC_ACK) & opts->suboptions) { 1065 u8 len; 1066 1067 if (OPTION_MPTCP_MPC_SYN & opts->suboptions) 1068 len = TCPOLEN_MPTCP_MPC_SYN; 1069 else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions) 1070 len = TCPOLEN_MPTCP_MPC_SYNACK; 1071 else if (opts->ext_copy.data_len) 1072 len = TCPOLEN_MPTCP_MPC_ACK_DATA; 1073 else 1074 len = TCPOLEN_MPTCP_MPC_ACK; 1075 1076 *ptr++ = mptcp_option(MPTCPOPT_MP_CAPABLE, len, 1077 MPTCP_SUPPORTED_VERSION, 1078 MPTCP_CAP_HMAC_SHA256); 1079 1080 if (!((OPTION_MPTCP_MPC_SYNACK | OPTION_MPTCP_MPC_ACK) & 1081 opts->suboptions)) 1082 goto mp_capable_done; 1083 1084 put_unaligned_be64(opts->sndr_key, ptr); 1085 ptr += 2; 1086 if (!((OPTION_MPTCP_MPC_ACK) & opts->suboptions)) 1087 goto mp_capable_done; 1088 1089 put_unaligned_be64(opts->rcvr_key, ptr); 1090 ptr += 2; 1091 if (!opts->ext_copy.data_len) 1092 goto mp_capable_done; 1093 1094 put_unaligned_be32(opts->ext_copy.data_len << 16 | 1095 TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); 1096 ptr += 1; 1097 } 1098 1099 mp_capable_done: 1100 if ((OPTION_MPTCP_ADD_ADDR 1101 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 1102 | OPTION_MPTCP_ADD_ADDR6 1103 #endif 1104 ) & opts->suboptions) { 1105 u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE; 1106 u8 echo = MPTCP_ADDR_ECHO; 1107 1108 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 1109 if (OPTION_MPTCP_ADD_ADDR6 & opts->suboptions) 1110 len = TCPOLEN_MPTCP_ADD_ADDR6_BASE; 1111 #endif 1112 1113 if (opts->port) 1114 len += TCPOLEN_MPTCP_PORT_LEN; 1115 1116 if (opts->ahmac) { 1117 len += sizeof(opts->ahmac); 1118 echo = 0; 1119 } 1120 1121 *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR, 1122 len, echo, opts->addr_id); 1123 if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) { 1124 memcpy((u8 *)ptr, (u8 *)&opts->addr.s_addr, 4); 1125 ptr += 1; 1126 } 1127 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 1128 else if (OPTION_MPTCP_ADD_ADDR6 & opts->suboptions) { 1129 memcpy((u8 *)ptr, opts->addr6.s6_addr, 16); 1130 ptr += 4; 1131 } 1132 #endif 1133 1134 if (!opts->port) { 1135 if (opts->ahmac) { 1136 put_unaligned_be64(opts->ahmac, ptr); 1137 ptr += 2; 1138 } 1139 } else { 1140 if (opts->ahmac) { 1141 u8 *bptr = (u8 *)ptr; 1142 1143 put_unaligned_be16(opts->port, bptr); 1144 bptr += 2; 1145 put_unaligned_be64(opts->ahmac, bptr); 1146 bptr += 8; 1147 put_unaligned_be16(TCPOPT_NOP << 8 | 1148 TCPOPT_NOP, bptr); 1149 1150 ptr += 3; 1151 } else { 1152 put_unaligned_be32(opts->port << 16 | 1153 TCPOPT_NOP << 8 | 1154 TCPOPT_NOP, ptr); 1155 ptr += 1; 1156 } 1157 } 1158 } 1159 1160 if (OPTION_MPTCP_RM_ADDR & opts->suboptions) { 1161 *ptr++ = mptcp_option(MPTCPOPT_RM_ADDR, 1162 TCPOLEN_MPTCP_RM_ADDR_BASE, 1163 0, opts->rm_id); 1164 } 1165 1166 if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) { 1167 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, 1168 TCPOLEN_MPTCP_MPJ_SYN, 1169 opts->backup, opts->join_id); 1170 put_unaligned_be32(opts->token, ptr); 1171 ptr += 1; 1172 put_unaligned_be32(opts->nonce, ptr); 1173 ptr += 1; 1174 } 1175 1176 if (OPTION_MPTCP_MPJ_SYNACK & opts->suboptions) { 1177 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, 1178 TCPOLEN_MPTCP_MPJ_SYNACK, 1179 opts->backup, opts->join_id); 1180 put_unaligned_be64(opts->thmac, ptr); 1181 ptr += 2; 1182 put_unaligned_be32(opts->nonce, ptr); 1183 ptr += 1; 1184 } 1185 1186 if (OPTION_MPTCP_MPJ_ACK & opts->suboptions) { 1187 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, 1188 TCPOLEN_MPTCP_MPJ_ACK, 0, 0); 1189 memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN); 1190 ptr += 5; 1191 } 1192 1193 if (opts->ext_copy.use_ack || opts->ext_copy.use_map) { 1194 struct mptcp_ext *mpext = &opts->ext_copy; 1195 u8 len = TCPOLEN_MPTCP_DSS_BASE; 1196 u8 flags = 0; 1197 1198 if (mpext->use_ack) { 1199 flags = MPTCP_DSS_HAS_ACK; 1200 if (mpext->ack64) { 1201 len += TCPOLEN_MPTCP_DSS_ACK64; 1202 flags |= MPTCP_DSS_ACK64; 1203 } else { 1204 len += TCPOLEN_MPTCP_DSS_ACK32; 1205 } 1206 } 1207 1208 if (mpext->use_map) { 1209 len += TCPOLEN_MPTCP_DSS_MAP64; 1210 1211 /* Use only 64-bit mapping flags for now, add 1212 * support for optional 32-bit mappings later. 1213 */ 1214 flags |= MPTCP_DSS_HAS_MAP | MPTCP_DSS_DSN64; 1215 if (mpext->data_fin) 1216 flags |= MPTCP_DSS_DATA_FIN; 1217 } 1218 1219 *ptr++ = mptcp_option(MPTCPOPT_DSS, len, 0, flags); 1220 1221 if (mpext->use_ack) { 1222 if (mpext->ack64) { 1223 put_unaligned_be64(mpext->data_ack, ptr); 1224 ptr += 2; 1225 } else { 1226 put_unaligned_be32(mpext->data_ack32, ptr); 1227 ptr += 1; 1228 } 1229 } 1230 1231 if (mpext->use_map) { 1232 put_unaligned_be64(mpext->data_seq, ptr); 1233 ptr += 2; 1234 put_unaligned_be32(mpext->subflow_seq, ptr); 1235 ptr += 1; 1236 put_unaligned_be32(mpext->data_len << 16 | 1237 TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); 1238 } 1239 } 1240 1241 if (tp) 1242 mptcp_set_rwin(tp); 1243 } 1244