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 opts->ext_copy.use_ack = 0; 610 opts->ext_copy.use_map = 0; 611 remaining += opt_size; 612 drop_other_suboptions = true; 613 } 614 615 if (!mptcp_pm_should_add_signal(msk) || 616 !(mptcp_pm_add_addr_signal(msk, remaining, &saddr, &echo, &port))) 617 return false; 618 619 len = mptcp_add_addr_len(saddr.family, echo, port); 620 if (remaining < len) 621 return false; 622 623 *size = len; 624 if (drop_other_suboptions) 625 *size -= opt_size; 626 opts->addr_id = saddr.id; 627 if (port) 628 opts->port = ntohs(saddr.port); 629 if (saddr.family == AF_INET) { 630 opts->suboptions |= OPTION_MPTCP_ADD_ADDR; 631 opts->addr = saddr.addr; 632 if (!echo) { 633 opts->ahmac = add_addr_generate_hmac(msk->local_key, 634 msk->remote_key, 635 opts->addr_id, 636 &opts->addr); 637 } 638 } 639 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 640 else if (saddr.family == AF_INET6) { 641 opts->suboptions |= OPTION_MPTCP_ADD_ADDR6; 642 opts->addr6 = saddr.addr6; 643 if (!echo) { 644 opts->ahmac = add_addr6_generate_hmac(msk->local_key, 645 msk->remote_key, 646 opts->addr_id, 647 &opts->addr6); 648 } 649 } 650 #endif 651 pr_debug("addr_id=%d, ahmac=%llu, echo=%d, port=%d", 652 opts->addr_id, opts->ahmac, echo, opts->port); 653 654 return true; 655 } 656 657 static bool mptcp_established_options_rm_addr(struct sock *sk, 658 unsigned int *size, 659 unsigned int remaining, 660 struct mptcp_out_options *opts) 661 { 662 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 663 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 664 u8 rm_id; 665 666 if (!mptcp_pm_should_rm_signal(msk) || 667 !(mptcp_pm_rm_addr_signal(msk, remaining, &rm_id))) 668 return false; 669 670 if (remaining < TCPOLEN_MPTCP_RM_ADDR_BASE) 671 return false; 672 673 *size = TCPOLEN_MPTCP_RM_ADDR_BASE; 674 opts->suboptions |= OPTION_MPTCP_RM_ADDR; 675 opts->rm_id = rm_id; 676 677 pr_debug("rm_id=%d", opts->rm_id); 678 679 return true; 680 } 681 682 bool mptcp_established_options(struct sock *sk, struct sk_buff *skb, 683 unsigned int *size, unsigned int remaining, 684 struct mptcp_out_options *opts) 685 { 686 unsigned int opt_size = 0; 687 bool ret = false; 688 689 opts->suboptions = 0; 690 691 if (unlikely(mptcp_check_fallback(sk))) 692 return false; 693 694 /* prevent adding of any MPTCP related options on reset packet 695 * until we support MP_TCPRST/MP_FASTCLOSE 696 */ 697 if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) 698 return false; 699 700 if (mptcp_established_options_mp(sk, skb, &opt_size, remaining, opts)) 701 ret = true; 702 else if (mptcp_established_options_dss(sk, skb, &opt_size, remaining, 703 opts)) 704 ret = true; 705 706 /* we reserved enough space for the above options, and exceeding the 707 * TCP option space would be fatal 708 */ 709 if (WARN_ON_ONCE(opt_size > remaining)) 710 return false; 711 712 *size += opt_size; 713 remaining -= opt_size; 714 if (mptcp_established_options_add_addr(sk, skb, &opt_size, remaining, opts)) { 715 *size += opt_size; 716 remaining -= opt_size; 717 ret = true; 718 } else if (mptcp_established_options_rm_addr(sk, &opt_size, remaining, opts)) { 719 *size += opt_size; 720 remaining -= opt_size; 721 ret = true; 722 } 723 724 return ret; 725 } 726 727 bool mptcp_synack_options(const struct request_sock *req, unsigned int *size, 728 struct mptcp_out_options *opts) 729 { 730 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); 731 732 if (subflow_req->mp_capable) { 733 opts->suboptions = OPTION_MPTCP_MPC_SYNACK; 734 opts->sndr_key = subflow_req->local_key; 735 *size = TCPOLEN_MPTCP_MPC_SYNACK; 736 pr_debug("subflow_req=%p, local_key=%llu", 737 subflow_req, subflow_req->local_key); 738 return true; 739 } else if (subflow_req->mp_join) { 740 opts->suboptions = OPTION_MPTCP_MPJ_SYNACK; 741 opts->backup = subflow_req->backup; 742 opts->join_id = subflow_req->local_id; 743 opts->thmac = subflow_req->thmac; 744 opts->nonce = subflow_req->local_nonce; 745 pr_debug("req=%p, bkup=%u, id=%u, thmac=%llu, nonce=%u", 746 subflow_req, opts->backup, opts->join_id, 747 opts->thmac, opts->nonce); 748 *size = TCPOLEN_MPTCP_MPJ_SYNACK; 749 return true; 750 } 751 return false; 752 } 753 754 static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk, 755 struct mptcp_subflow_context *subflow, 756 struct sk_buff *skb, 757 struct mptcp_options_received *mp_opt) 758 { 759 /* here we can process OoO, in-window pkts, only in-sequence 4th ack 760 * will make the subflow fully established 761 */ 762 if (likely(subflow->fully_established)) { 763 /* on passive sockets, check for 3rd ack retransmission 764 * note that msk is always set by subflow_syn_recv_sock() 765 * for mp_join subflows 766 */ 767 if (TCP_SKB_CB(skb)->seq == subflow->ssn_offset + 1 && 768 TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq && 769 subflow->mp_join && mp_opt->mp_join && 770 READ_ONCE(msk->pm.server_side)) 771 tcp_send_ack(ssk); 772 goto fully_established; 773 } 774 775 /* we must process OoO packets before the first subflow is fully 776 * established. OoO packets are instead a protocol violation 777 * for MP_JOIN subflows as the peer must not send any data 778 * before receiving the forth ack - cfr. RFC 8684 section 3.2. 779 */ 780 if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) { 781 if (subflow->mp_join) 782 goto reset; 783 return subflow->mp_capable; 784 } 785 786 if (mp_opt->dss && mp_opt->use_ack) { 787 /* subflows are fully established as soon as we get any 788 * additional ack. 789 */ 790 subflow->fully_established = 1; 791 WRITE_ONCE(msk->fully_established, true); 792 goto fully_established; 793 } 794 795 if (mp_opt->add_addr) { 796 WRITE_ONCE(msk->fully_established, true); 797 return true; 798 } 799 800 /* If the first established packet does not contain MP_CAPABLE + data 801 * then fallback to TCP. Fallback scenarios requires a reset for 802 * MP_JOIN subflows. 803 */ 804 if (!mp_opt->mp_capable) { 805 if (subflow->mp_join) 806 goto reset; 807 subflow->mp_capable = 0; 808 pr_fallback(msk); 809 __mptcp_do_fallback(msk); 810 return false; 811 } 812 813 if (unlikely(!READ_ONCE(msk->pm.server_side))) 814 pr_warn_once("bogus mpc option on established client sk"); 815 mptcp_subflow_fully_established(subflow, mp_opt); 816 817 fully_established: 818 /* if the subflow is not already linked into the conn_list, we can't 819 * notify the PM: this subflow is still on the listener queue 820 * and the PM possibly acquiring the subflow lock could race with 821 * the listener close 822 */ 823 if (likely(subflow->pm_notified) || list_empty(&subflow->node)) 824 return true; 825 826 subflow->pm_notified = 1; 827 if (subflow->mp_join) { 828 clear_3rdack_retransmission(ssk); 829 mptcp_pm_subflow_established(msk, subflow); 830 } else { 831 mptcp_pm_fully_established(msk); 832 } 833 return true; 834 835 reset: 836 mptcp_subflow_reset(ssk); 837 return false; 838 } 839 840 static u64 expand_ack(u64 old_ack, u64 cur_ack, bool use_64bit) 841 { 842 u32 old_ack32, cur_ack32; 843 844 if (use_64bit) 845 return cur_ack; 846 847 old_ack32 = (u32)old_ack; 848 cur_ack32 = (u32)cur_ack; 849 cur_ack = (old_ack & GENMASK_ULL(63, 32)) + cur_ack32; 850 if (unlikely(before(cur_ack32, old_ack32))) 851 return cur_ack + (1LL << 32); 852 return cur_ack; 853 } 854 855 static void ack_update_msk(struct mptcp_sock *msk, 856 struct sock *ssk, 857 struct mptcp_options_received *mp_opt) 858 { 859 u64 new_wnd_end, new_snd_una, snd_nxt = READ_ONCE(msk->snd_nxt); 860 struct sock *sk = (struct sock *)msk; 861 u64 old_snd_una; 862 863 mptcp_data_lock(sk); 864 865 /* avoid ack expansion on update conflict, to reduce the risk of 866 * wrongly expanding to a future ack sequence number, which is way 867 * more dangerous than missing an ack 868 */ 869 old_snd_una = msk->snd_una; 870 new_snd_una = expand_ack(old_snd_una, mp_opt->data_ack, mp_opt->ack64); 871 872 /* ACK for data not even sent yet? Ignore. */ 873 if (after64(new_snd_una, snd_nxt)) 874 new_snd_una = old_snd_una; 875 876 new_wnd_end = new_snd_una + tcp_sk(ssk)->snd_wnd; 877 878 if (after64(new_wnd_end, msk->wnd_end)) 879 msk->wnd_end = new_wnd_end; 880 881 /* this assumes mptcp_incoming_options() is invoked after tcp_ack() */ 882 if (after64(msk->wnd_end, READ_ONCE(msk->snd_nxt)) && 883 sk_stream_memory_free(ssk)) 884 __mptcp_check_push(sk, ssk); 885 886 if (after64(new_snd_una, old_snd_una)) { 887 msk->snd_una = new_snd_una; 888 __mptcp_data_acked(sk); 889 } 890 mptcp_data_unlock(sk); 891 } 892 893 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit) 894 { 895 /* Skip if DATA_FIN was already received. 896 * If updating simultaneously with the recvmsg loop, values 897 * should match. If they mismatch, the peer is misbehaving and 898 * we will prefer the most recent information. 899 */ 900 if (READ_ONCE(msk->rcv_data_fin) || !READ_ONCE(msk->first)) 901 return false; 902 903 WRITE_ONCE(msk->rcv_data_fin_seq, 904 expand_ack(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit)); 905 WRITE_ONCE(msk->rcv_data_fin, 1); 906 907 return true; 908 } 909 910 static bool add_addr_hmac_valid(struct mptcp_sock *msk, 911 struct mptcp_options_received *mp_opt) 912 { 913 u64 hmac = 0; 914 915 if (mp_opt->echo) 916 return true; 917 918 if (mp_opt->family == MPTCP_ADDR_IPVERSION_4) 919 hmac = add_addr_generate_hmac(msk->remote_key, 920 msk->local_key, 921 mp_opt->addr_id, &mp_opt->addr); 922 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 923 else 924 hmac = add_addr6_generate_hmac(msk->remote_key, 925 msk->local_key, 926 mp_opt->addr_id, &mp_opt->addr6); 927 #endif 928 929 pr_debug("msk=%p, ahmac=%llu, mp_opt->ahmac=%llu\n", 930 msk, (unsigned long long)hmac, 931 (unsigned long long)mp_opt->ahmac); 932 933 return hmac == mp_opt->ahmac; 934 } 935 936 void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb) 937 { 938 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 939 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 940 struct mptcp_options_received mp_opt; 941 struct mptcp_ext *mpext; 942 943 if (__mptcp_check_fallback(msk)) { 944 /* Keep it simple and unconditionally trigger send data cleanup and 945 * pending queue spooling. We will need to acquire the data lock 946 * for more accurate checks, and once the lock is acquired, such 947 * helpers are cheap. 948 */ 949 mptcp_data_lock(subflow->conn); 950 if (sk_stream_memory_free(sk)) 951 __mptcp_check_push(subflow->conn, sk); 952 __mptcp_data_acked(subflow->conn); 953 mptcp_data_unlock(subflow->conn); 954 return; 955 } 956 957 mptcp_get_options(skb, &mp_opt); 958 if (!check_fully_established(msk, sk, subflow, skb, &mp_opt)) 959 return; 960 961 if (mp_opt.fastclose && 962 msk->local_key == mp_opt.rcvr_key) { 963 WRITE_ONCE(msk->rcv_fastclose, true); 964 mptcp_schedule_work((struct sock *)msk); 965 } 966 967 if (mp_opt.add_addr && add_addr_hmac_valid(msk, &mp_opt)) { 968 struct mptcp_addr_info addr; 969 970 addr.port = htons(mp_opt.port); 971 addr.id = mp_opt.addr_id; 972 if (mp_opt.family == MPTCP_ADDR_IPVERSION_4) { 973 addr.family = AF_INET; 974 addr.addr = mp_opt.addr; 975 } 976 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 977 else if (mp_opt.family == MPTCP_ADDR_IPVERSION_6) { 978 addr.family = AF_INET6; 979 addr.addr6 = mp_opt.addr6; 980 } 981 #endif 982 if (!mp_opt.echo) { 983 mptcp_pm_add_addr_received(msk, &addr); 984 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR); 985 } else { 986 mptcp_pm_del_add_timer(msk, &addr); 987 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD); 988 } 989 mp_opt.add_addr = 0; 990 } 991 992 if (mp_opt.rm_addr) { 993 mptcp_pm_rm_addr_received(msk, mp_opt.rm_id); 994 mp_opt.rm_addr = 0; 995 } 996 997 if (!mp_opt.dss) 998 return; 999 1000 /* we can't wait for recvmsg() to update the ack_seq, otherwise 1001 * monodirectional flows will stuck 1002 */ 1003 if (mp_opt.use_ack) 1004 ack_update_msk(msk, sk, &mp_opt); 1005 1006 /* Zero-data-length packets are dropped by the caller and not 1007 * propagated to the MPTCP layer, so the skb extension does not 1008 * need to be allocated or populated. DATA_FIN information, if 1009 * present, needs to be updated here before the skb is freed. 1010 */ 1011 if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) { 1012 if (mp_opt.data_fin && mp_opt.data_len == 1 && 1013 mptcp_update_rcv_data_fin(msk, mp_opt.data_seq, mp_opt.dsn64) && 1014 schedule_work(&msk->work)) 1015 sock_hold(subflow->conn); 1016 1017 return; 1018 } 1019 1020 mpext = skb_ext_add(skb, SKB_EXT_MPTCP); 1021 if (!mpext) 1022 return; 1023 1024 memset(mpext, 0, sizeof(*mpext)); 1025 1026 if (mp_opt.use_map) { 1027 if (mp_opt.mpc_map) { 1028 /* this is an MP_CAPABLE carrying MPTCP data 1029 * we know this map the first chunk of data 1030 */ 1031 mptcp_crypto_key_sha(subflow->remote_key, NULL, 1032 &mpext->data_seq); 1033 mpext->data_seq++; 1034 mpext->subflow_seq = 1; 1035 mpext->dsn64 = 1; 1036 mpext->mpc_map = 1; 1037 mpext->data_fin = 0; 1038 } else { 1039 mpext->data_seq = mp_opt.data_seq; 1040 mpext->subflow_seq = mp_opt.subflow_seq; 1041 mpext->dsn64 = mp_opt.dsn64; 1042 mpext->data_fin = mp_opt.data_fin; 1043 } 1044 mpext->data_len = mp_opt.data_len; 1045 mpext->use_map = 1; 1046 } 1047 } 1048 1049 static void mptcp_set_rwin(const struct tcp_sock *tp) 1050 { 1051 const struct sock *ssk = (const struct sock *)tp; 1052 const struct mptcp_subflow_context *subflow; 1053 struct mptcp_sock *msk; 1054 u64 ack_seq; 1055 1056 subflow = mptcp_subflow_ctx(ssk); 1057 msk = mptcp_sk(subflow->conn); 1058 1059 ack_seq = READ_ONCE(msk->ack_seq) + tp->rcv_wnd; 1060 1061 if (after64(ack_seq, READ_ONCE(msk->rcv_wnd_sent))) 1062 WRITE_ONCE(msk->rcv_wnd_sent, ack_seq); 1063 } 1064 1065 void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp, 1066 struct mptcp_out_options *opts) 1067 { 1068 if ((OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK | 1069 OPTION_MPTCP_MPC_ACK) & opts->suboptions) { 1070 u8 len; 1071 1072 if (OPTION_MPTCP_MPC_SYN & opts->suboptions) 1073 len = TCPOLEN_MPTCP_MPC_SYN; 1074 else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions) 1075 len = TCPOLEN_MPTCP_MPC_SYNACK; 1076 else if (opts->ext_copy.data_len) 1077 len = TCPOLEN_MPTCP_MPC_ACK_DATA; 1078 else 1079 len = TCPOLEN_MPTCP_MPC_ACK; 1080 1081 *ptr++ = mptcp_option(MPTCPOPT_MP_CAPABLE, len, 1082 MPTCP_SUPPORTED_VERSION, 1083 MPTCP_CAP_HMAC_SHA256); 1084 1085 if (!((OPTION_MPTCP_MPC_SYNACK | OPTION_MPTCP_MPC_ACK) & 1086 opts->suboptions)) 1087 goto mp_capable_done; 1088 1089 put_unaligned_be64(opts->sndr_key, ptr); 1090 ptr += 2; 1091 if (!((OPTION_MPTCP_MPC_ACK) & opts->suboptions)) 1092 goto mp_capable_done; 1093 1094 put_unaligned_be64(opts->rcvr_key, ptr); 1095 ptr += 2; 1096 if (!opts->ext_copy.data_len) 1097 goto mp_capable_done; 1098 1099 put_unaligned_be32(opts->ext_copy.data_len << 16 | 1100 TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); 1101 ptr += 1; 1102 } 1103 1104 mp_capable_done: 1105 if ((OPTION_MPTCP_ADD_ADDR 1106 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 1107 | OPTION_MPTCP_ADD_ADDR6 1108 #endif 1109 ) & opts->suboptions) { 1110 u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE; 1111 u8 echo = MPTCP_ADDR_ECHO; 1112 1113 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 1114 if (OPTION_MPTCP_ADD_ADDR6 & opts->suboptions) 1115 len = TCPOLEN_MPTCP_ADD_ADDR6_BASE; 1116 #endif 1117 1118 if (opts->port) 1119 len += TCPOLEN_MPTCP_PORT_LEN; 1120 1121 if (opts->ahmac) { 1122 len += sizeof(opts->ahmac); 1123 echo = 0; 1124 } 1125 1126 *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR, 1127 len, echo, opts->addr_id); 1128 if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) { 1129 memcpy((u8 *)ptr, (u8 *)&opts->addr.s_addr, 4); 1130 ptr += 1; 1131 } 1132 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 1133 else if (OPTION_MPTCP_ADD_ADDR6 & opts->suboptions) { 1134 memcpy((u8 *)ptr, opts->addr6.s6_addr, 16); 1135 ptr += 4; 1136 } 1137 #endif 1138 1139 if (!opts->port) { 1140 if (opts->ahmac) { 1141 put_unaligned_be64(opts->ahmac, ptr); 1142 ptr += 2; 1143 } 1144 } else { 1145 if (opts->ahmac) { 1146 u8 *bptr = (u8 *)ptr; 1147 1148 put_unaligned_be16(opts->port, bptr); 1149 bptr += 2; 1150 put_unaligned_be64(opts->ahmac, bptr); 1151 bptr += 8; 1152 put_unaligned_be16(TCPOPT_NOP << 8 | 1153 TCPOPT_NOP, bptr); 1154 1155 ptr += 3; 1156 } else { 1157 put_unaligned_be32(opts->port << 16 | 1158 TCPOPT_NOP << 8 | 1159 TCPOPT_NOP, ptr); 1160 ptr += 1; 1161 } 1162 } 1163 } 1164 1165 if (OPTION_MPTCP_RM_ADDR & opts->suboptions) { 1166 *ptr++ = mptcp_option(MPTCPOPT_RM_ADDR, 1167 TCPOLEN_MPTCP_RM_ADDR_BASE, 1168 0, opts->rm_id); 1169 } 1170 1171 if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) { 1172 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, 1173 TCPOLEN_MPTCP_MPJ_SYN, 1174 opts->backup, opts->join_id); 1175 put_unaligned_be32(opts->token, ptr); 1176 ptr += 1; 1177 put_unaligned_be32(opts->nonce, ptr); 1178 ptr += 1; 1179 } 1180 1181 if (OPTION_MPTCP_MPJ_SYNACK & opts->suboptions) { 1182 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, 1183 TCPOLEN_MPTCP_MPJ_SYNACK, 1184 opts->backup, opts->join_id); 1185 put_unaligned_be64(opts->thmac, ptr); 1186 ptr += 2; 1187 put_unaligned_be32(opts->nonce, ptr); 1188 ptr += 1; 1189 } 1190 1191 if (OPTION_MPTCP_MPJ_ACK & opts->suboptions) { 1192 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, 1193 TCPOLEN_MPTCP_MPJ_ACK, 0, 0); 1194 memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN); 1195 ptr += 5; 1196 } 1197 1198 if (opts->ext_copy.use_ack || opts->ext_copy.use_map) { 1199 struct mptcp_ext *mpext = &opts->ext_copy; 1200 u8 len = TCPOLEN_MPTCP_DSS_BASE; 1201 u8 flags = 0; 1202 1203 if (mpext->use_ack) { 1204 flags = MPTCP_DSS_HAS_ACK; 1205 if (mpext->ack64) { 1206 len += TCPOLEN_MPTCP_DSS_ACK64; 1207 flags |= MPTCP_DSS_ACK64; 1208 } else { 1209 len += TCPOLEN_MPTCP_DSS_ACK32; 1210 } 1211 } 1212 1213 if (mpext->use_map) { 1214 len += TCPOLEN_MPTCP_DSS_MAP64; 1215 1216 /* Use only 64-bit mapping flags for now, add 1217 * support for optional 32-bit mappings later. 1218 */ 1219 flags |= MPTCP_DSS_HAS_MAP | MPTCP_DSS_DSN64; 1220 if (mpext->data_fin) 1221 flags |= MPTCP_DSS_DATA_FIN; 1222 } 1223 1224 *ptr++ = mptcp_option(MPTCPOPT_DSS, len, 0, flags); 1225 1226 if (mpext->use_ack) { 1227 if (mpext->ack64) { 1228 put_unaligned_be64(mpext->data_ack, ptr); 1229 ptr += 2; 1230 } else { 1231 put_unaligned_be32(mpext->data_ack32, ptr); 1232 ptr += 1; 1233 } 1234 } 1235 1236 if (mpext->use_map) { 1237 put_unaligned_be64(mpext->data_seq, ptr); 1238 ptr += 2; 1239 put_unaligned_be32(mpext->subflow_seq, ptr); 1240 ptr += 1; 1241 put_unaligned_be32(mpext->data_len << 16 | 1242 TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); 1243 } 1244 } 1245 1246 if (tp) 1247 mptcp_set_rwin(tp); 1248 } 1249