1 // SPDX-License-Identifier: GPL-2.0
4 * Copyright (c) 2017 - 2019, Intel Corporation.
7 #define pr_fmt(fmt) "MPTCP: " fmt
9 #include <linux/kernel.h>
10 #include <crypto/sha2.h>
12 #include <net/mptcp.h>
16 #include <trace/events/mptcp.h>
18 static bool mptcp_cap_flag_sha256(u8 flags)
20 return (flags & MPTCP_CAP_FLAG_MASK) == MPTCP_CAP_HMAC_SHA256;
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)
27 u8 subtype = *ptr >> 4;
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;
40 expected_opsize = TCPOLEN_MPTCP_MPC_ACK;
42 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_ACK)
43 expected_opsize = TCPOLEN_MPTCP_MPC_SYNACK;
45 expected_opsize = TCPOLEN_MPTCP_MPC_SYN;
48 /* Cfr RFC 8684 Section 3.3.0:
49 * If a checksum is present but its use had
50 * not been negotiated in the MP_CAPABLE handshake, the receiver MUST
51 * close the subflow with a RST, as it is not behaving as negotiated.
52 * If a checksum is not present when its use has been negotiated, the
53 * receiver MUST close the subflow with a RST, as it is considered
55 * We parse even option with mismatching csum presence, so that
56 * later in subflow_data_ready we can trigger the reset.
58 if (opsize != expected_opsize &&
59 (expected_opsize != TCPOLEN_MPTCP_MPC_ACK_DATA ||
60 opsize != TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM))
63 /* try to be gentle vs future versions on the initial syn */
64 version = *ptr++ & MPTCP_VERSION_MASK;
65 if (opsize != TCPOLEN_MPTCP_MPC_SYN) {
66 if (version != MPTCP_SUPPORTED_VERSION)
68 } else if (version < MPTCP_SUPPORTED_VERSION) {
73 if (!mptcp_cap_flag_sha256(flags) ||
74 (flags & MPTCP_CAP_EXTENSIBILITY))
77 /* RFC 6824, Section 3.1:
78 * "For the Checksum Required bit (labeled "A"), if either
79 * host requires the use of checksums, checksums MUST be used.
80 * In other words, the only way for checksums not to be used
81 * is if both hosts in their SYNs set A=0."
83 if (flags & MPTCP_CAP_CHECKSUM_REQD)
84 mp_opt->suboptions |= OPTION_MPTCP_CSUMREQD;
86 mp_opt->deny_join_id0 = !!(flags & MPTCP_CAP_DENY_JOIN_ID0);
88 mp_opt->suboptions |= OPTIONS_MPTCP_MPC;
89 if (opsize >= TCPOLEN_MPTCP_MPC_SYNACK) {
90 mp_opt->sndr_key = get_unaligned_be64(ptr);
93 if (opsize >= TCPOLEN_MPTCP_MPC_ACK) {
94 mp_opt->rcvr_key = get_unaligned_be64(ptr);
97 if (opsize >= TCPOLEN_MPTCP_MPC_ACK_DATA) {
99 * "the data parameters in a MP_CAPABLE are semantically
100 * equivalent to those in a DSS option and can be used
103 mp_opt->suboptions |= OPTION_MPTCP_DSS;
106 mp_opt->data_len = get_unaligned_be16(ptr);
109 if (opsize == TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM) {
110 mp_opt->csum = get_unaligned((__force __sum16 *)ptr);
111 mp_opt->suboptions |= OPTION_MPTCP_CSUMREQD;
114 pr_debug("MP_CAPABLE version=%x, flags=%x, optlen=%d sndr=%llu, rcvr=%llu len=%d csum=%u",
115 version, flags, opsize, mp_opt->sndr_key,
116 mp_opt->rcvr_key, mp_opt->data_len, mp_opt->csum);
119 case MPTCPOPT_MP_JOIN:
120 mp_opt->suboptions |= OPTIONS_MPTCP_MPJ;
121 if (opsize == TCPOLEN_MPTCP_MPJ_SYN) {
122 mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP;
123 mp_opt->join_id = *ptr++;
124 mp_opt->token = get_unaligned_be32(ptr);
126 mp_opt->nonce = get_unaligned_be32(ptr);
128 pr_debug("MP_JOIN bkup=%u, id=%u, token=%u, nonce=%u",
129 mp_opt->backup, mp_opt->join_id,
130 mp_opt->token, mp_opt->nonce);
131 } else if (opsize == TCPOLEN_MPTCP_MPJ_SYNACK) {
132 mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP;
133 mp_opt->join_id = *ptr++;
134 mp_opt->thmac = get_unaligned_be64(ptr);
136 mp_opt->nonce = get_unaligned_be32(ptr);
138 pr_debug("MP_JOIN bkup=%u, id=%u, thmac=%llu, nonce=%u",
139 mp_opt->backup, mp_opt->join_id,
140 mp_opt->thmac, mp_opt->nonce);
141 } else if (opsize == TCPOLEN_MPTCP_MPJ_ACK) {
143 memcpy(mp_opt->hmac, ptr, MPTCPOPT_HMAC_LEN);
144 pr_debug("MP_JOIN hmac");
146 mp_opt->suboptions &= ~OPTIONS_MPTCP_MPJ;
154 /* we must clear 'mpc_map' be able to detect MP_CAPABLE
155 * map vs DSS map in mptcp_incoming_options(), and reconstruct
156 * map info accordingly
159 flags = (*ptr++) & MPTCP_DSS_FLAG_MASK;
160 mp_opt->data_fin = (flags & MPTCP_DSS_DATA_FIN) != 0;
161 mp_opt->dsn64 = (flags & MPTCP_DSS_DSN64) != 0;
162 mp_opt->use_map = (flags & MPTCP_DSS_HAS_MAP) != 0;
163 mp_opt->ack64 = (flags & MPTCP_DSS_ACK64) != 0;
164 mp_opt->use_ack = (flags & MPTCP_DSS_HAS_ACK);
166 pr_debug("data_fin=%d dsn64=%d use_map=%d ack64=%d use_ack=%d",
167 mp_opt->data_fin, mp_opt->dsn64,
168 mp_opt->use_map, mp_opt->ack64,
171 expected_opsize = TCPOLEN_MPTCP_DSS_BASE;
173 if (mp_opt->use_ack) {
175 expected_opsize += TCPOLEN_MPTCP_DSS_ACK64;
177 expected_opsize += TCPOLEN_MPTCP_DSS_ACK32;
180 if (mp_opt->use_map) {
182 expected_opsize += TCPOLEN_MPTCP_DSS_MAP64;
184 expected_opsize += TCPOLEN_MPTCP_DSS_MAP32;
187 /* Always parse any csum presence combination, we will enforce
188 * RFC 8684 Section 3.3.0 checks later in subflow_data_ready
190 if (opsize != expected_opsize &&
191 opsize != expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM)
194 mp_opt->suboptions |= OPTION_MPTCP_DSS;
195 if (mp_opt->use_ack) {
197 mp_opt->data_ack = get_unaligned_be64(ptr);
200 mp_opt->data_ack = get_unaligned_be32(ptr);
204 pr_debug("data_ack=%llu", mp_opt->data_ack);
207 if (mp_opt->use_map) {
209 mp_opt->data_seq = get_unaligned_be64(ptr);
212 mp_opt->data_seq = get_unaligned_be32(ptr);
216 mp_opt->subflow_seq = get_unaligned_be32(ptr);
219 mp_opt->data_len = get_unaligned_be16(ptr);
222 if (opsize == expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM) {
223 mp_opt->suboptions |= OPTION_MPTCP_CSUMREQD;
224 mp_opt->csum = get_unaligned((__force __sum16 *)ptr);
228 pr_debug("data_seq=%llu subflow_seq=%u data_len=%u csum=%d:%u",
229 mp_opt->data_seq, mp_opt->subflow_seq,
230 mp_opt->data_len, !!(mp_opt->suboptions & OPTION_MPTCP_CSUMREQD),
236 case MPTCPOPT_ADD_ADDR:
237 mp_opt->echo = (*ptr++) & MPTCP_ADDR_ECHO;
239 if (opsize == TCPOLEN_MPTCP_ADD_ADDR ||
240 opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT)
241 mp_opt->addr.family = AF_INET;
242 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
243 else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6 ||
244 opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT)
245 mp_opt->addr.family = AF_INET6;
250 if (opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE ||
251 opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT)
252 mp_opt->addr.family = AF_INET;
253 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
254 else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE ||
255 opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT)
256 mp_opt->addr.family = AF_INET6;
262 mp_opt->suboptions |= OPTION_MPTCP_ADD_ADDR;
263 mp_opt->addr.id = *ptr++;
264 mp_opt->addr.port = 0;
266 if (mp_opt->addr.family == AF_INET) {
267 memcpy((u8 *)&mp_opt->addr.addr.s_addr, (u8 *)ptr, 4);
269 if (opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT ||
270 opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) {
271 mp_opt->addr.port = htons(get_unaligned_be16(ptr));
275 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
277 memcpy(mp_opt->addr.addr6.s6_addr, (u8 *)ptr, 16);
279 if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT ||
280 opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) {
281 mp_opt->addr.port = htons(get_unaligned_be16(ptr));
287 mp_opt->ahmac = get_unaligned_be64(ptr);
290 pr_debug("ADD_ADDR%s: id=%d, ahmac=%llu, echo=%d, port=%d",
291 (mp_opt->addr.family == AF_INET6) ? "6" : "",
292 mp_opt->addr.id, mp_opt->ahmac, mp_opt->echo, ntohs(mp_opt->addr.port));
295 case MPTCPOPT_RM_ADDR:
296 if (opsize < TCPOLEN_MPTCP_RM_ADDR_BASE + 1 ||
297 opsize > TCPOLEN_MPTCP_RM_ADDR_BASE + MPTCP_RM_IDS_MAX)
302 mp_opt->suboptions |= OPTION_MPTCP_RM_ADDR;
303 mp_opt->rm_list.nr = opsize - TCPOLEN_MPTCP_RM_ADDR_BASE;
304 for (i = 0; i < mp_opt->rm_list.nr; i++)
305 mp_opt->rm_list.ids[i] = *ptr++;
306 pr_debug("RM_ADDR: rm_list_nr=%d", mp_opt->rm_list.nr);
309 case MPTCPOPT_MP_PRIO:
310 if (opsize != TCPOLEN_MPTCP_PRIO)
313 mp_opt->suboptions |= OPTION_MPTCP_PRIO;
314 mp_opt->backup = *ptr++ & MPTCP_PRIO_BKUP;
315 pr_debug("MP_PRIO: prio=%d", mp_opt->backup);
318 case MPTCPOPT_MP_FASTCLOSE:
319 if (opsize != TCPOLEN_MPTCP_FASTCLOSE)
323 mp_opt->rcvr_key = get_unaligned_be64(ptr);
325 mp_opt->suboptions |= OPTION_MPTCP_FASTCLOSE;
326 pr_debug("MP_FASTCLOSE: recv_key=%llu", mp_opt->rcvr_key);
330 if (opsize != TCPOLEN_MPTCP_RST)
333 if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST))
336 mp_opt->suboptions |= OPTION_MPTCP_RST;
338 mp_opt->reset_transient = flags & MPTCP_RST_TRANSIENT;
339 mp_opt->reset_reason = *ptr;
340 pr_debug("MP_RST: transient=%u reason=%u",
341 mp_opt->reset_transient, mp_opt->reset_reason);
344 case MPTCPOPT_MP_FAIL:
345 if (opsize != TCPOLEN_MPTCP_FAIL)
349 mp_opt->suboptions |= OPTION_MPTCP_FAIL;
350 mp_opt->fail_seq = get_unaligned_be64(ptr);
351 pr_debug("MP_FAIL: data_seq=%llu", mp_opt->fail_seq);
359 void mptcp_get_options(const struct sk_buff *skb,
360 struct mptcp_options_received *mp_opt)
362 const struct tcphdr *th = tcp_hdr(skb);
363 const unsigned char *ptr;
366 /* initialize option status */
367 mp_opt->suboptions = 0;
369 length = (th->doff * 4) - sizeof(struct tcphdr);
370 ptr = (const unsigned char *)(th + 1);
379 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
386 if (opsize < 2) /* "silly options" */
389 return; /* don't parse partial options */
390 if (opcode == TCPOPT_MPTCP)
391 mptcp_parse_option(skb, ptr, opsize, mp_opt);
398 bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
399 unsigned int *size, struct mptcp_out_options *opts)
401 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
403 /* we will use snd_isn to detect first pkt [re]transmission
404 * in mptcp_established_options_mp()
406 subflow->snd_isn = TCP_SKB_CB(skb)->end_seq;
407 if (subflow->request_mptcp) {
408 opts->suboptions = OPTION_MPTCP_MPC_SYN;
409 opts->csum_reqd = mptcp_is_checksum_enabled(sock_net(sk));
410 opts->allow_join_id0 = mptcp_allow_join_id0(sock_net(sk));
411 *size = TCPOLEN_MPTCP_MPC_SYN;
413 } else if (subflow->request_join) {
414 pr_debug("remote_token=%u, nonce=%u", subflow->remote_token,
415 subflow->local_nonce);
416 opts->suboptions = OPTION_MPTCP_MPJ_SYN;
417 opts->join_id = subflow->local_id;
418 opts->token = subflow->remote_token;
419 opts->nonce = subflow->local_nonce;
420 opts->backup = subflow->request_bkup;
421 *size = TCPOLEN_MPTCP_MPJ_SYN;
427 static void clear_3rdack_retransmission(struct sock *sk)
429 struct inet_connection_sock *icsk = inet_csk(sk);
431 sk_stop_timer(sk, &icsk->icsk_delack_timer);
432 icsk->icsk_ack.timeout = 0;
433 icsk->icsk_ack.ato = 0;
434 icsk->icsk_ack.pending &= ~(ICSK_ACK_SCHED | ICSK_ACK_TIMER);
437 static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb,
438 bool snd_data_fin_enable,
440 unsigned int remaining,
441 struct mptcp_out_options *opts)
443 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
444 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
445 struct mptcp_ext *mpext;
446 unsigned int data_len;
449 /* When skb is not available, we better over-estimate the emitted
450 * options len. A full DSS option (28 bytes) is longer than
451 * TCPOLEN_MPTCP_MPC_ACK_DATA(22) or TCPOLEN_MPTCP_MPJ_ACK(24), so
452 * tell the caller to defer the estimate to
453 * mptcp_established_options_dss(), which will reserve enough space.
458 /* MPC/MPJ needed only on 3rd ack packet, DATA_FIN and TCP shutdown take precedence */
459 if (subflow->fully_established || snd_data_fin_enable ||
460 subflow->snd_isn != TCP_SKB_CB(skb)->seq ||
461 sk->sk_state != TCP_ESTABLISHED)
464 if (subflow->mp_capable) {
465 mpext = mptcp_get_ext(skb);
466 data_len = mpext ? mpext->data_len : 0;
468 /* we will check ops->data_len in mptcp_write_options() to
469 * discriminate between TCPOLEN_MPTCP_MPC_ACK_DATA and
470 * TCPOLEN_MPTCP_MPC_ACK
472 opts->data_len = data_len;
473 opts->suboptions = OPTION_MPTCP_MPC_ACK;
474 opts->sndr_key = subflow->local_key;
475 opts->rcvr_key = subflow->remote_key;
476 opts->csum_reqd = READ_ONCE(msk->csum_enabled);
477 opts->allow_join_id0 = mptcp_allow_join_id0(sock_net(sk));
480 * The MP_CAPABLE option is carried on the SYN, SYN/ACK, and ACK
481 * packets that start the first subflow of an MPTCP connection,
482 * as well as the first packet that carries data
485 len = TCPOLEN_MPTCP_MPC_ACK_DATA;
486 if (opts->csum_reqd) {
487 /* we need to propagate more info to csum the pseudo hdr */
488 opts->data_seq = mpext->data_seq;
489 opts->subflow_seq = mpext->subflow_seq;
490 opts->csum = mpext->csum;
491 len += TCPOLEN_MPTCP_DSS_CHECKSUM;
493 *size = ALIGN(len, 4);
495 *size = TCPOLEN_MPTCP_MPC_ACK;
498 pr_debug("subflow=%p, local_key=%llu, remote_key=%llu map_len=%d",
499 subflow, subflow->local_key, subflow->remote_key,
503 } else if (subflow->mp_join) {
504 opts->suboptions = OPTION_MPTCP_MPJ_ACK;
505 memcpy(opts->hmac, subflow->hmac, MPTCPOPT_HMAC_LEN);
506 *size = TCPOLEN_MPTCP_MPJ_ACK;
507 pr_debug("subflow=%p", subflow);
509 /* we can use the full delegate action helper only from BH context
510 * If we are in process context - sk is flushing the backlog at
511 * socket lock release time - just set the appropriate flag, will
512 * be handled by the release callback
514 if (sock_owned_by_user(sk))
515 set_bit(MPTCP_DELEGATE_ACK, &subflow->delegated_status);
517 mptcp_subflow_delegate(subflow, MPTCP_DELEGATE_ACK);
523 static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow,
524 struct sk_buff *skb, struct mptcp_ext *ext)
526 /* The write_seq value has already been incremented, so the actual
527 * sequence number for the DATA_FIN is one less.
529 u64 data_fin_tx_seq = READ_ONCE(mptcp_sk(subflow->conn)->write_seq) - 1;
531 if (!ext->use_map || !skb->len) {
532 /* RFC6824 requires a DSS mapping with specific values
533 * if DATA_FIN is set but no data payload is mapped
538 ext->data_seq = data_fin_tx_seq;
539 ext->subflow_seq = 0;
541 } else if (ext->data_seq + ext->data_len == data_fin_tx_seq) {
542 /* If there's an existing DSS mapping and it is the
543 * final mapping, DATA_FIN consumes 1 additional byte of
551 static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
552 bool snd_data_fin_enable,
554 unsigned int remaining,
555 struct mptcp_out_options *opts)
557 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
558 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
559 unsigned int dss_size = 0;
560 struct mptcp_ext *mpext;
561 unsigned int ack_size;
565 opts->csum_reqd = READ_ONCE(msk->csum_enabled);
566 mpext = skb ? mptcp_get_ext(skb) : NULL;
568 if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) {
569 unsigned int map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64;
573 map_size += TCPOLEN_MPTCP_DSS_CHECKSUM;
575 opts->ext_copy = *mpext;
578 remaining -= map_size;
580 if (skb && snd_data_fin_enable)
581 mptcp_write_data_fin(subflow, skb, &opts->ext_copy);
582 opts->suboptions = OPTION_MPTCP_DSS;
586 /* passive sockets msk will set the 'can_ack' after accept(), even
587 * if the first subflow may have the already the remote key handy
589 opts->ext_copy.use_ack = 0;
590 if (!READ_ONCE(msk->can_ack)) {
591 *size = ALIGN(dss_size, 4);
595 ack_seq = READ_ONCE(msk->ack_seq);
596 if (READ_ONCE(msk->use_64bit_ack)) {
597 ack_size = TCPOLEN_MPTCP_DSS_ACK64;
598 opts->ext_copy.data_ack = ack_seq;
599 opts->ext_copy.ack64 = 1;
601 ack_size = TCPOLEN_MPTCP_DSS_ACK32;
602 opts->ext_copy.data_ack32 = (uint32_t)ack_seq;
603 opts->ext_copy.ack64 = 0;
605 opts->ext_copy.use_ack = 1;
606 opts->suboptions = OPTION_MPTCP_DSS;
607 WRITE_ONCE(msk->old_wspace, __mptcp_space((struct sock *)msk));
609 /* Add kind/length/subtype/flag overhead if mapping is not populated */
611 ack_size += TCPOLEN_MPTCP_DSS_BASE;
613 dss_size += ack_size;
615 *size = ALIGN(dss_size, 4);
619 static u64 add_addr_generate_hmac(u64 key1, u64 key2,
620 struct mptcp_addr_info *addr)
622 u16 port = ntohs(addr->port);
623 u8 hmac[SHA256_DIGEST_SIZE];
628 if (addr->family == AF_INET) {
629 memcpy(&msg[i], &addr->addr.s_addr, 4);
632 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
633 else if (addr->family == AF_INET6) {
634 memcpy(&msg[i], &addr->addr6.s6_addr, 16);
638 msg[i++] = port >> 8;
639 msg[i++] = port & 0xFF;
641 mptcp_crypto_hmac_sha(key1, key2, msg, i, hmac);
643 return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]);
646 static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *skb,
648 unsigned int remaining,
649 struct mptcp_out_options *opts)
651 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
652 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
653 bool drop_other_suboptions = false;
654 unsigned int opt_size = *size;
658 /* add addr will strip the existing options, be sure to avoid breaking
661 if (!mptcp_pm_should_add_signal(msk) ||
662 (opts->suboptions & (OPTION_MPTCP_MPJ_ACK | OPTION_MPTCP_MPC_ACK)) ||
663 !mptcp_pm_add_addr_signal(msk, skb, opt_size, remaining, &opts->addr,
664 &echo, &drop_other_suboptions))
667 if (drop_other_suboptions)
668 remaining += opt_size;
669 len = mptcp_add_addr_len(opts->addr.family, echo, !!opts->addr.port);
674 if (drop_other_suboptions) {
675 pr_debug("drop other suboptions");
676 opts->suboptions = 0;
678 /* note that e.g. DSS could have written into the memory
679 * aliased by ahmac, we must reset the field here
680 * to avoid appending the hmac even for ADD_ADDR echo
686 opts->suboptions |= OPTION_MPTCP_ADD_ADDR;
688 opts->ahmac = add_addr_generate_hmac(msk->local_key,
692 pr_debug("addr_id=%d, ahmac=%llu, echo=%d, port=%d",
693 opts->addr.id, opts->ahmac, echo, ntohs(opts->addr.port));
698 static bool mptcp_established_options_rm_addr(struct sock *sk,
700 unsigned int remaining,
701 struct mptcp_out_options *opts)
703 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
704 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
705 struct mptcp_rm_list rm_list;
708 if (!mptcp_pm_should_rm_signal(msk) ||
709 !(mptcp_pm_rm_addr_signal(msk, remaining, &rm_list)))
712 len = mptcp_rm_addr_len(&rm_list);
719 opts->suboptions |= OPTION_MPTCP_RM_ADDR;
720 opts->rm_list = rm_list;
722 for (i = 0; i < opts->rm_list.nr; i++)
723 pr_debug("rm_list_ids[%d]=%d", i, opts->rm_list.ids[i]);
728 static bool mptcp_established_options_mp_prio(struct sock *sk,
730 unsigned int remaining,
731 struct mptcp_out_options *opts)
733 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
735 /* can't send MP_PRIO with MPC, as they share the same option space:
736 * 'backup'. Also it makes no sense at all
738 if (!subflow->send_mp_prio || (opts->suboptions & OPTIONS_MPTCP_MPC))
741 /* account for the trailing 'nop' option */
742 if (remaining < TCPOLEN_MPTCP_PRIO_ALIGN)
745 *size = TCPOLEN_MPTCP_PRIO_ALIGN;
746 opts->suboptions |= OPTION_MPTCP_PRIO;
747 opts->backup = subflow->request_bkup;
749 pr_debug("prio=%d", opts->backup);
754 static noinline bool mptcp_established_options_rst(struct sock *sk, struct sk_buff *skb,
756 unsigned int remaining,
757 struct mptcp_out_options *opts)
759 const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
761 if (remaining < TCPOLEN_MPTCP_RST)
764 *size = TCPOLEN_MPTCP_RST;
765 opts->suboptions |= OPTION_MPTCP_RST;
766 opts->reset_transient = subflow->reset_transient;
767 opts->reset_reason = subflow->reset_reason;
772 static bool mptcp_established_options_fastclose(struct sock *sk,
774 unsigned int remaining,
775 struct mptcp_out_options *opts)
777 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
778 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
780 if (likely(!subflow->send_fastclose))
783 if (remaining < TCPOLEN_MPTCP_FASTCLOSE)
786 *size = TCPOLEN_MPTCP_FASTCLOSE;
787 opts->suboptions |= OPTION_MPTCP_FASTCLOSE;
788 opts->rcvr_key = msk->remote_key;
790 pr_debug("FASTCLOSE key=%llu", opts->rcvr_key);
794 static bool mptcp_established_options_mp_fail(struct sock *sk,
796 unsigned int remaining,
797 struct mptcp_out_options *opts)
799 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
801 if (likely(!subflow->send_mp_fail))
804 if (remaining < TCPOLEN_MPTCP_FAIL)
807 *size = TCPOLEN_MPTCP_FAIL;
808 opts->suboptions |= OPTION_MPTCP_FAIL;
809 opts->fail_seq = subflow->map_seq;
811 pr_debug("MP_FAIL fail_seq=%llu", opts->fail_seq);
816 bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
817 unsigned int *size, unsigned int remaining,
818 struct mptcp_out_options *opts)
820 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
821 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
822 unsigned int opt_size = 0;
826 opts->suboptions = 0;
828 if (unlikely(__mptcp_check_fallback(msk) && !mptcp_check_infinite_map(skb)))
831 if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) {
832 if (mptcp_established_options_fastclose(sk, &opt_size, remaining, opts) ||
833 mptcp_established_options_mp_fail(sk, &opt_size, remaining, opts)) {
835 remaining -= opt_size;
836 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPFASTCLOSETX);
838 /* MP_RST can be used with MP_FASTCLOSE and MP_FAIL if there is room */
839 if (mptcp_established_options_rst(sk, skb, &opt_size, remaining, opts)) {
841 remaining -= opt_size;
842 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPRSTTX);
847 snd_data_fin = mptcp_data_fin_enabled(msk);
848 if (mptcp_established_options_mp(sk, skb, snd_data_fin, &opt_size, remaining, opts))
850 else if (mptcp_established_options_dss(sk, skb, snd_data_fin, &opt_size, remaining, opts)) {
851 unsigned int mp_fail_size;
854 if (mptcp_established_options_mp_fail(sk, &mp_fail_size,
855 remaining - opt_size, opts)) {
856 *size += opt_size + mp_fail_size;
857 remaining -= opt_size - mp_fail_size;
862 /* we reserved enough space for the above options, and exceeding the
863 * TCP option space would be fatal
865 if (WARN_ON_ONCE(opt_size > remaining))
869 remaining -= opt_size;
870 if (mptcp_established_options_add_addr(sk, skb, &opt_size, remaining, opts)) {
872 remaining -= opt_size;
874 } else if (mptcp_established_options_rm_addr(sk, &opt_size, remaining, opts)) {
876 remaining -= opt_size;
880 if (mptcp_established_options_mp_prio(sk, &opt_size, remaining, opts)) {
882 remaining -= opt_size;
889 bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
890 struct mptcp_out_options *opts)
892 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
894 if (subflow_req->mp_capable) {
895 opts->suboptions = OPTION_MPTCP_MPC_SYNACK;
896 opts->sndr_key = subflow_req->local_key;
897 opts->csum_reqd = subflow_req->csum_reqd;
898 opts->allow_join_id0 = subflow_req->allow_join_id0;
899 *size = TCPOLEN_MPTCP_MPC_SYNACK;
900 pr_debug("subflow_req=%p, local_key=%llu",
901 subflow_req, subflow_req->local_key);
903 } else if (subflow_req->mp_join) {
904 opts->suboptions = OPTION_MPTCP_MPJ_SYNACK;
905 opts->backup = subflow_req->backup;
906 opts->join_id = subflow_req->local_id;
907 opts->thmac = subflow_req->thmac;
908 opts->nonce = subflow_req->local_nonce;
909 pr_debug("req=%p, bkup=%u, id=%u, thmac=%llu, nonce=%u",
910 subflow_req, opts->backup, opts->join_id,
911 opts->thmac, opts->nonce);
912 *size = TCPOLEN_MPTCP_MPJ_SYNACK;
918 static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk,
919 struct mptcp_subflow_context *subflow,
921 struct mptcp_options_received *mp_opt)
923 /* here we can process OoO, in-window pkts, only in-sequence 4th ack
924 * will make the subflow fully established
926 if (likely(subflow->fully_established)) {
927 /* on passive sockets, check for 3rd ack retransmission
928 * note that msk is always set by subflow_syn_recv_sock()
929 * for mp_join subflows
931 if (TCP_SKB_CB(skb)->seq == subflow->ssn_offset + 1 &&
932 TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq &&
933 subflow->mp_join && (mp_opt->suboptions & OPTIONS_MPTCP_MPJ) &&
934 !subflow->request_join)
936 goto fully_established;
939 /* we must process OoO packets before the first subflow is fully
940 * established. OoO packets are instead a protocol violation
941 * for MP_JOIN subflows as the peer must not send any data
942 * before receiving the forth ack - cfr. RFC 8684 section 3.2.
944 if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) {
945 if (subflow->mp_join)
947 return subflow->mp_capable;
950 if (((mp_opt->suboptions & OPTION_MPTCP_DSS) && mp_opt->use_ack) ||
951 ((mp_opt->suboptions & OPTION_MPTCP_ADD_ADDR) && !mp_opt->echo)) {
952 /* subflows are fully established as soon as we get any
953 * additional ack, including ADD_ADDR.
955 subflow->fully_established = 1;
956 WRITE_ONCE(msk->fully_established, true);
957 goto fully_established;
960 /* If the first established packet does not contain MP_CAPABLE + data
961 * then fallback to TCP. Fallback scenarios requires a reset for
964 if (!(mp_opt->suboptions & OPTIONS_MPTCP_MPC)) {
965 if (subflow->mp_join)
967 subflow->mp_capable = 0;
969 __mptcp_do_fallback(msk);
973 if (mp_opt->deny_join_id0)
974 WRITE_ONCE(msk->pm.remote_deny_join_id0, true);
976 if (unlikely(!READ_ONCE(msk->pm.server_side)))
977 pr_warn_once("bogus mpc option on established client sk");
978 mptcp_subflow_fully_established(subflow, mp_opt);
981 /* if the subflow is not already linked into the conn_list, we can't
982 * notify the PM: this subflow is still on the listener queue
983 * and the PM possibly acquiring the subflow lock could race with
986 if (likely(subflow->pm_notified) || list_empty(&subflow->node))
989 subflow->pm_notified = 1;
990 if (subflow->mp_join) {
991 clear_3rdack_retransmission(ssk);
992 mptcp_pm_subflow_established(msk);
994 mptcp_pm_fully_established(msk, ssk, GFP_ATOMIC);
999 mptcp_subflow_reset(ssk);
1003 u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq)
1005 u32 old_seq32, cur_seq32;
1007 old_seq32 = (u32)old_seq;
1008 cur_seq32 = (u32)cur_seq;
1009 cur_seq = (old_seq & GENMASK_ULL(63, 32)) + cur_seq32;
1010 if (unlikely(cur_seq32 < old_seq32 && before(old_seq32, cur_seq32)))
1011 return cur_seq + (1LL << 32);
1013 /* reverse wrap could happen, too */
1014 if (unlikely(cur_seq32 > old_seq32 && after(old_seq32, cur_seq32)))
1015 return cur_seq - (1LL << 32);
1019 static void ack_update_msk(struct mptcp_sock *msk,
1021 struct mptcp_options_received *mp_opt)
1023 u64 new_wnd_end, new_snd_una, snd_nxt = READ_ONCE(msk->snd_nxt);
1024 struct sock *sk = (struct sock *)msk;
1027 mptcp_data_lock(sk);
1029 /* avoid ack expansion on update conflict, to reduce the risk of
1030 * wrongly expanding to a future ack sequence number, which is way
1031 * more dangerous than missing an ack
1033 old_snd_una = msk->snd_una;
1034 new_snd_una = mptcp_expand_seq(old_snd_una, mp_opt->data_ack, mp_opt->ack64);
1036 /* ACK for data not even sent yet? Ignore.*/
1037 if (unlikely(after64(new_snd_una, snd_nxt)))
1038 new_snd_una = old_snd_una;
1040 new_wnd_end = new_snd_una + tcp_sk(ssk)->snd_wnd;
1042 if (after64(new_wnd_end, msk->wnd_end))
1043 msk->wnd_end = new_wnd_end;
1045 /* this assumes mptcp_incoming_options() is invoked after tcp_ack() */
1046 if (after64(msk->wnd_end, READ_ONCE(msk->snd_nxt)))
1047 __mptcp_check_push(sk, ssk);
1049 if (after64(new_snd_una, old_snd_una)) {
1050 msk->snd_una = new_snd_una;
1051 __mptcp_data_acked(sk);
1053 mptcp_data_unlock(sk);
1055 trace_ack_update_msk(mp_opt->data_ack,
1056 old_snd_una, new_snd_una,
1057 new_wnd_end, msk->wnd_end);
1060 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit)
1062 /* Skip if DATA_FIN was already received.
1063 * If updating simultaneously with the recvmsg loop, values
1064 * should match. If they mismatch, the peer is misbehaving and
1065 * we will prefer the most recent information.
1067 if (READ_ONCE(msk->rcv_data_fin))
1070 WRITE_ONCE(msk->rcv_data_fin_seq,
1071 mptcp_expand_seq(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit));
1072 WRITE_ONCE(msk->rcv_data_fin, 1);
1077 static bool add_addr_hmac_valid(struct mptcp_sock *msk,
1078 struct mptcp_options_received *mp_opt)
1085 hmac = add_addr_generate_hmac(msk->remote_key,
1089 pr_debug("msk=%p, ahmac=%llu, mp_opt->ahmac=%llu\n",
1090 msk, hmac, mp_opt->ahmac);
1092 return hmac == mp_opt->ahmac;
1095 /* Return false if a subflow has been reset, else return true */
1096 bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
1098 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1099 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
1100 struct mptcp_options_received mp_opt;
1101 struct mptcp_ext *mpext;
1103 if (__mptcp_check_fallback(msk)) {
1104 /* Keep it simple and unconditionally trigger send data cleanup and
1105 * pending queue spooling. We will need to acquire the data lock
1106 * for more accurate checks, and once the lock is acquired, such
1107 * helpers are cheap.
1109 mptcp_data_lock(subflow->conn);
1110 if (sk_stream_memory_free(sk))
1111 __mptcp_check_push(subflow->conn, sk);
1112 __mptcp_data_acked(subflow->conn);
1113 mptcp_data_unlock(subflow->conn);
1117 mptcp_get_options(skb, &mp_opt);
1119 /* The subflow can be in close state only if check_fully_established()
1120 * just sent a reset. If so, tell the caller to ignore the current packet.
1122 if (!check_fully_established(msk, sk, subflow, skb, &mp_opt))
1123 return sk->sk_state != TCP_CLOSE;
1125 if (unlikely(mp_opt.suboptions != OPTION_MPTCP_DSS)) {
1126 if ((mp_opt.suboptions & OPTION_MPTCP_FASTCLOSE) &&
1127 msk->local_key == mp_opt.rcvr_key) {
1128 WRITE_ONCE(msk->rcv_fastclose, true);
1129 mptcp_schedule_work((struct sock *)msk);
1130 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPFASTCLOSERX);
1133 if ((mp_opt.suboptions & OPTION_MPTCP_ADD_ADDR) &&
1134 add_addr_hmac_valid(msk, &mp_opt)) {
1136 mptcp_pm_add_addr_received(sk, &mp_opt.addr);
1137 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR);
1139 mptcp_pm_add_addr_echoed(msk, &mp_opt.addr);
1140 mptcp_pm_del_add_timer(msk, &mp_opt.addr, true);
1141 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD);
1144 if (mp_opt.addr.port)
1145 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_PORTADD);
1148 if (mp_opt.suboptions & OPTION_MPTCP_RM_ADDR)
1149 mptcp_pm_rm_addr_received(msk, &mp_opt.rm_list);
1151 if (mp_opt.suboptions & OPTION_MPTCP_PRIO) {
1152 mptcp_pm_mp_prio_received(sk, mp_opt.backup);
1153 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPPRIORX);
1156 if (mp_opt.suboptions & OPTION_MPTCP_FAIL) {
1157 mptcp_pm_mp_fail_received(sk, mp_opt.fail_seq);
1158 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPFAILRX);
1161 if (mp_opt.suboptions & OPTION_MPTCP_RST) {
1162 subflow->reset_seen = 1;
1163 subflow->reset_reason = mp_opt.reset_reason;
1164 subflow->reset_transient = mp_opt.reset_transient;
1165 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPRSTRX);
1168 if (!(mp_opt.suboptions & OPTION_MPTCP_DSS))
1172 /* we can't wait for recvmsg() to update the ack_seq, otherwise
1173 * monodirectional flows will stuck
1176 ack_update_msk(msk, sk, &mp_opt);
1178 /* Zero-data-length packets are dropped by the caller and not
1179 * propagated to the MPTCP layer, so the skb extension does not
1180 * need to be allocated or populated. DATA_FIN information, if
1181 * present, needs to be updated here before the skb is freed.
1183 if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) {
1184 if (mp_opt.data_fin && mp_opt.data_len == 1 &&
1185 mptcp_update_rcv_data_fin(msk, mp_opt.data_seq, mp_opt.dsn64) &&
1186 schedule_work(&msk->work))
1187 sock_hold(subflow->conn);
1192 mpext = skb_ext_add(skb, SKB_EXT_MPTCP);
1196 memset(mpext, 0, sizeof(*mpext));
1198 if (likely(mp_opt.use_map)) {
1199 if (mp_opt.mpc_map) {
1200 /* this is an MP_CAPABLE carrying MPTCP data
1201 * we know this map the first chunk of data
1203 mptcp_crypto_key_sha(subflow->remote_key, NULL,
1206 mpext->subflow_seq = 1;
1209 mpext->data_fin = 0;
1211 mpext->data_seq = mp_opt.data_seq;
1212 mpext->subflow_seq = mp_opt.subflow_seq;
1213 mpext->dsn64 = mp_opt.dsn64;
1214 mpext->data_fin = mp_opt.data_fin;
1216 mpext->data_len = mp_opt.data_len;
1218 mpext->csum_reqd = !!(mp_opt.suboptions & OPTION_MPTCP_CSUMREQD);
1220 if (mpext->csum_reqd)
1221 mpext->csum = mp_opt.csum;
1227 static void mptcp_set_rwin(struct tcp_sock *tp, struct tcphdr *th)
1229 const struct sock *ssk = (const struct sock *)tp;
1230 struct mptcp_subflow_context *subflow;
1231 u64 ack_seq, rcv_wnd_old, rcv_wnd_new;
1232 struct mptcp_sock *msk;
1236 subflow = mptcp_subflow_ctx(ssk);
1237 msk = mptcp_sk(subflow->conn);
1239 ack_seq = READ_ONCE(msk->ack_seq);
1240 rcv_wnd_new = ack_seq + tp->rcv_wnd;
1242 rcv_wnd_old = atomic64_read(&msk->rcv_wnd_sent);
1243 if (after64(rcv_wnd_new, rcv_wnd_old)) {
1247 rcv_wnd = atomic64_cmpxchg(&msk->rcv_wnd_sent, rcv_wnd_old, rcv_wnd_new);
1249 if (rcv_wnd == rcv_wnd_old)
1251 if (before64(rcv_wnd_new, rcv_wnd)) {
1252 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_RCVWNDCONFLICTUPDATE);
1255 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_RCVWNDCONFLICT);
1256 rcv_wnd_old = rcv_wnd;
1261 if (rcv_wnd_new != rcv_wnd_old) {
1263 win = rcv_wnd_old - ack_seq;
1264 tp->rcv_wnd = min_t(u64, win, U32_MAX);
1265 new_win = tp->rcv_wnd;
1267 /* Make sure we do not exceed the maximum possible
1270 if (unlikely(th->syn))
1271 new_win = min(new_win, 65535U) << tp->rx_opt.rcv_wscale;
1272 if (!tp->rx_opt.rcv_wscale &&
1273 sock_net(ssk)->ipv4.sysctl_tcp_workaround_signed_windows)
1274 new_win = min(new_win, MAX_TCP_WINDOW);
1276 new_win = min(new_win, (65535U << tp->rx_opt.rcv_wscale));
1278 /* RFC1323 scaling applied */
1279 new_win >>= tp->rx_opt.rcv_wscale;
1280 th->window = htons(new_win);
1281 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_RCVWNDSHARED);
1285 __sum16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __wsum sum)
1287 struct csum_pseudo_header header;
1290 /* cfr RFC 8684 3.3.1.:
1291 * the data sequence number used in the pseudo-header is
1292 * always the 64-bit value, irrespective of what length is used in the
1293 * DSS option itself.
1295 header.data_seq = cpu_to_be64(data_seq);
1296 header.subflow_seq = htonl(subflow_seq);
1297 header.data_len = htons(data_len);
1300 csum = csum_partial(&header, sizeof(header), sum);
1301 return csum_fold(csum);
1304 static __sum16 mptcp_make_csum(const struct mptcp_ext *mpext)
1306 return __mptcp_make_csum(mpext->data_seq, mpext->subflow_seq, mpext->data_len,
1307 ~csum_unfold(mpext->csum));
1310 static void put_len_csum(u16 len, __sum16 csum, void *data)
1312 __sum16 *sumptr = data + 2;
1315 put_unaligned_be16(len, ptr);
1317 put_unaligned(csum, sumptr);
1320 void mptcp_write_options(struct tcphdr *th, __be32 *ptr, struct tcp_sock *tp,
1321 struct mptcp_out_options *opts)
1323 const struct sock *ssk = (const struct sock *)tp;
1324 struct mptcp_subflow_context *subflow;
1326 /* Which options can be used together?
1328 * X: mutually exclusive
1329 * O: often used together
1330 * C: can be used together in some cases
1331 * P: could be used together but we prefer not to (optimisations)
1333 * Opt: | MPC | MPJ | DSS | ADD | RM | PRIO | FAIL | FC |
1334 * ------|------|------|------|------|------|------|------|------|
1335 * MPC |------|------|------|------|------|------|------|------|
1336 * MPJ | X |------|------|------|------|------|------|------|
1337 * DSS | X | X |------|------|------|------|------|------|
1338 * ADD | X | X | P |------|------|------|------|------|
1339 * RM | C | C | C | P |------|------|------|------|
1340 * PRIO | X | C | C | C | C |------|------|------|
1341 * FAIL | X | X | C | X | X | X |------|------|
1342 * FC | X | X | X | X | X | X | X |------|
1343 * RST | X | X | X | X | X | X | O | O |
1344 * ------|------|------|------|------|------|------|------|------|
1346 * The same applies in mptcp_established_options() function.
1348 if (likely(OPTION_MPTCP_DSS & opts->suboptions)) {
1349 struct mptcp_ext *mpext = &opts->ext_copy;
1350 u8 len = TCPOLEN_MPTCP_DSS_BASE;
1353 if (mpext->use_ack) {
1354 flags = MPTCP_DSS_HAS_ACK;
1356 len += TCPOLEN_MPTCP_DSS_ACK64;
1357 flags |= MPTCP_DSS_ACK64;
1359 len += TCPOLEN_MPTCP_DSS_ACK32;
1363 if (mpext->use_map) {
1364 len += TCPOLEN_MPTCP_DSS_MAP64;
1366 /* Use only 64-bit mapping flags for now, add
1367 * support for optional 32-bit mappings later.
1369 flags |= MPTCP_DSS_HAS_MAP | MPTCP_DSS_DSN64;
1370 if (mpext->data_fin)
1371 flags |= MPTCP_DSS_DATA_FIN;
1373 if (opts->csum_reqd)
1374 len += TCPOLEN_MPTCP_DSS_CHECKSUM;
1377 *ptr++ = mptcp_option(MPTCPOPT_DSS, len, 0, flags);
1379 if (mpext->use_ack) {
1381 put_unaligned_be64(mpext->data_ack, ptr);
1384 put_unaligned_be32(mpext->data_ack32, ptr);
1389 if (mpext->use_map) {
1390 put_unaligned_be64(mpext->data_seq, ptr);
1392 put_unaligned_be32(mpext->subflow_seq, ptr);
1394 if (opts->csum_reqd) {
1395 /* data_len == 0 is reserved for the infinite mapping,
1396 * the checksum will also be set to 0.
1398 put_len_csum(mpext->data_len,
1399 (mpext->data_len ? mptcp_make_csum(mpext) : 0),
1402 put_unaligned_be32(mpext->data_len << 16 |
1403 TCPOPT_NOP << 8 | TCPOPT_NOP, ptr);
1408 /* We might need to add MP_FAIL options in rare cases */
1409 if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions))
1411 } else if (OPTIONS_MPTCP_MPC & opts->suboptions) {
1412 u8 len, flag = MPTCP_CAP_HMAC_SHA256;
1414 if (OPTION_MPTCP_MPC_SYN & opts->suboptions) {
1415 len = TCPOLEN_MPTCP_MPC_SYN;
1416 } else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions) {
1417 len = TCPOLEN_MPTCP_MPC_SYNACK;
1418 } else if (opts->data_len) {
1419 len = TCPOLEN_MPTCP_MPC_ACK_DATA;
1420 if (opts->csum_reqd)
1421 len += TCPOLEN_MPTCP_DSS_CHECKSUM;
1423 len = TCPOLEN_MPTCP_MPC_ACK;
1426 if (opts->csum_reqd)
1427 flag |= MPTCP_CAP_CHECKSUM_REQD;
1429 if (!opts->allow_join_id0)
1430 flag |= MPTCP_CAP_DENY_JOIN_ID0;
1432 *ptr++ = mptcp_option(MPTCPOPT_MP_CAPABLE, len,
1433 MPTCP_SUPPORTED_VERSION,
1436 if (!((OPTION_MPTCP_MPC_SYNACK | OPTION_MPTCP_MPC_ACK) &
1438 goto mp_capable_done;
1440 put_unaligned_be64(opts->sndr_key, ptr);
1442 if (!((OPTION_MPTCP_MPC_ACK) & opts->suboptions))
1443 goto mp_capable_done;
1445 put_unaligned_be64(opts->rcvr_key, ptr);
1447 if (!opts->data_len)
1448 goto mp_capable_done;
1450 if (opts->csum_reqd) {
1451 put_len_csum(opts->data_len,
1452 __mptcp_make_csum(opts->data_seq,
1455 ~csum_unfold(opts->csum)),
1458 put_unaligned_be32(opts->data_len << 16 |
1459 TCPOPT_NOP << 8 | TCPOPT_NOP, ptr);
1463 /* MPC is additionally mutually exclusive with MP_PRIO */
1464 goto mp_capable_done;
1465 } else if (OPTIONS_MPTCP_MPJ & opts->suboptions) {
1466 if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) {
1467 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
1468 TCPOLEN_MPTCP_MPJ_SYN,
1469 opts->backup, opts->join_id);
1470 put_unaligned_be32(opts->token, ptr);
1472 put_unaligned_be32(opts->nonce, ptr);
1474 } else if (OPTION_MPTCP_MPJ_SYNACK & opts->suboptions) {
1475 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
1476 TCPOLEN_MPTCP_MPJ_SYNACK,
1477 opts->backup, opts->join_id);
1478 put_unaligned_be64(opts->thmac, ptr);
1480 put_unaligned_be32(opts->nonce, ptr);
1483 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
1484 TCPOLEN_MPTCP_MPJ_ACK, 0, 0);
1485 memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN);
1488 } else if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) {
1489 u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
1490 u8 echo = MPTCP_ADDR_ECHO;
1492 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1493 if (opts->addr.family == AF_INET6)
1494 len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
1497 if (opts->addr.port)
1498 len += TCPOLEN_MPTCP_PORT_LEN;
1501 len += sizeof(opts->ahmac);
1505 *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
1506 len, echo, opts->addr.id);
1507 if (opts->addr.family == AF_INET) {
1508 memcpy((u8 *)ptr, (u8 *)&opts->addr.addr.s_addr, 4);
1511 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1512 else if (opts->addr.family == AF_INET6) {
1513 memcpy((u8 *)ptr, opts->addr.addr6.s6_addr, 16);
1518 if (!opts->addr.port) {
1520 put_unaligned_be64(opts->ahmac, ptr);
1524 u16 port = ntohs(opts->addr.port);
1527 u8 *bptr = (u8 *)ptr;
1529 put_unaligned_be16(port, bptr);
1531 put_unaligned_be64(opts->ahmac, bptr);
1533 put_unaligned_be16(TCPOPT_NOP << 8 |
1538 put_unaligned_be32(port << 16 |
1544 } else if (unlikely(OPTION_MPTCP_FASTCLOSE & opts->suboptions)) {
1545 /* FASTCLOSE is mutually exclusive with others except RST */
1546 *ptr++ = mptcp_option(MPTCPOPT_MP_FASTCLOSE,
1547 TCPOLEN_MPTCP_FASTCLOSE,
1549 put_unaligned_be64(opts->rcvr_key, ptr);
1552 if (OPTION_MPTCP_RST & opts->suboptions)
1555 } else if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) {
1557 /* MP_FAIL is mutually exclusive with others except RST */
1558 subflow = mptcp_subflow_ctx(ssk);
1559 subflow->send_mp_fail = 0;
1561 *ptr++ = mptcp_option(MPTCPOPT_MP_FAIL,
1564 put_unaligned_be64(opts->fail_seq, ptr);
1567 if (OPTION_MPTCP_RST & opts->suboptions)
1570 } else if (unlikely(OPTION_MPTCP_RST & opts->suboptions)) {
1572 *ptr++ = mptcp_option(MPTCPOPT_RST,
1574 opts->reset_transient,
1575 opts->reset_reason);
1579 if (OPTION_MPTCP_PRIO & opts->suboptions) {
1580 subflow = mptcp_subflow_ctx(ssk);
1581 subflow->send_mp_prio = 0;
1583 *ptr++ = mptcp_option(MPTCPOPT_MP_PRIO,
1585 opts->backup, TCPOPT_NOP);
1589 if (OPTION_MPTCP_RM_ADDR & opts->suboptions) {
1592 *ptr++ = mptcp_option(MPTCPOPT_RM_ADDR,
1593 TCPOLEN_MPTCP_RM_ADDR_BASE + opts->rm_list.nr,
1594 0, opts->rm_list.ids[0]);
1596 while (i < opts->rm_list.nr) {
1597 u8 id1, id2, id3, id4;
1599 id1 = opts->rm_list.ids[i];
1600 id2 = i + 1 < opts->rm_list.nr ? opts->rm_list.ids[i + 1] : TCPOPT_NOP;
1601 id3 = i + 2 < opts->rm_list.nr ? opts->rm_list.ids[i + 2] : TCPOPT_NOP;
1602 id4 = i + 3 < opts->rm_list.nr ? opts->rm_list.ids[i + 3] : TCPOPT_NOP;
1603 put_unaligned_be32(id1 << 24 | id2 << 16 | id3 << 8 | id4, ptr);
1610 mptcp_set_rwin(tp, th);
1613 __be32 mptcp_get_reset_option(const struct sk_buff *skb)
1615 const struct mptcp_ext *ext = mptcp_get_ext(skb);
1619 flags = ext->reset_transient;
1620 reason = ext->reset_reason;
1622 return mptcp_option(MPTCPOPT_RST, TCPOLEN_MPTCP_RST,
1628 EXPORT_SYMBOL_GPL(mptcp_get_reset_option);