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 = (__force __sum16)get_unaligned_be16(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 = (__force __sum16)get_unaligned_be16(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;
329 if (opsize != TCPOLEN_MPTCP_RST)
332 if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST))
335 mp_opt->suboptions |= OPTION_MPTCP_RST;
337 mp_opt->reset_transient = flags & MPTCP_RST_TRANSIENT;
338 mp_opt->reset_reason = *ptr;
341 case MPTCPOPT_MP_FAIL:
342 if (opsize != TCPOLEN_MPTCP_FAIL)
346 mp_opt->suboptions |= OPTION_MPTCP_FAIL;
347 mp_opt->fail_seq = get_unaligned_be64(ptr);
348 pr_debug("MP_FAIL: data_seq=%llu", mp_opt->fail_seq);
356 void mptcp_get_options(const struct sock *sk,
357 const struct sk_buff *skb,
358 struct mptcp_options_received *mp_opt)
360 const struct tcphdr *th = tcp_hdr(skb);
361 const unsigned char *ptr;
364 /* initialize option status */
365 mp_opt->suboptions = 0;
367 length = (th->doff * 4) - sizeof(struct tcphdr);
368 ptr = (const unsigned char *)(th + 1);
377 case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
384 if (opsize < 2) /* "silly options" */
387 return; /* don't parse partial options */
388 if (opcode == TCPOPT_MPTCP)
389 mptcp_parse_option(skb, ptr, opsize, mp_opt);
396 bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
397 unsigned int *size, struct mptcp_out_options *opts)
399 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
401 /* we will use snd_isn to detect first pkt [re]transmission
402 * in mptcp_established_options_mp()
404 subflow->snd_isn = TCP_SKB_CB(skb)->end_seq;
405 if (subflow->request_mptcp) {
406 opts->suboptions = OPTION_MPTCP_MPC_SYN;
407 opts->csum_reqd = mptcp_is_checksum_enabled(sock_net(sk));
408 opts->allow_join_id0 = mptcp_allow_join_id0(sock_net(sk));
409 *size = TCPOLEN_MPTCP_MPC_SYN;
411 } else if (subflow->request_join) {
412 pr_debug("remote_token=%u, nonce=%u", subflow->remote_token,
413 subflow->local_nonce);
414 opts->suboptions = OPTION_MPTCP_MPJ_SYN;
415 opts->join_id = subflow->local_id;
416 opts->token = subflow->remote_token;
417 opts->nonce = subflow->local_nonce;
418 opts->backup = subflow->request_bkup;
419 *size = TCPOLEN_MPTCP_MPJ_SYN;
425 static void clear_3rdack_retransmission(struct sock *sk)
427 struct inet_connection_sock *icsk = inet_csk(sk);
429 sk_stop_timer(sk, &icsk->icsk_delack_timer);
430 icsk->icsk_ack.timeout = 0;
431 icsk->icsk_ack.ato = 0;
432 icsk->icsk_ack.pending &= ~(ICSK_ACK_SCHED | ICSK_ACK_TIMER);
435 static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb,
436 bool snd_data_fin_enable,
438 unsigned int remaining,
439 struct mptcp_out_options *opts)
441 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
442 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
443 struct mptcp_ext *mpext;
444 unsigned int data_len;
447 /* When skb is not available, we better over-estimate the emitted
448 * options len. A full DSS option (28 bytes) is longer than
449 * TCPOLEN_MPTCP_MPC_ACK_DATA(22) or TCPOLEN_MPTCP_MPJ_ACK(24), so
450 * tell the caller to defer the estimate to
451 * mptcp_established_options_dss(), which will reserve enough space.
456 /* MPC/MPJ needed only on 3rd ack packet, DATA_FIN and TCP shutdown take precedence */
457 if (subflow->fully_established || snd_data_fin_enable ||
458 subflow->snd_isn != TCP_SKB_CB(skb)->seq ||
459 sk->sk_state != TCP_ESTABLISHED)
462 if (subflow->mp_capable) {
463 mpext = mptcp_get_ext(skb);
464 data_len = mpext ? mpext->data_len : 0;
466 /* we will check ops->data_len in mptcp_write_options() to
467 * discriminate between TCPOLEN_MPTCP_MPC_ACK_DATA and
468 * TCPOLEN_MPTCP_MPC_ACK
470 opts->data_len = data_len;
471 opts->suboptions = OPTION_MPTCP_MPC_ACK;
472 opts->sndr_key = subflow->local_key;
473 opts->rcvr_key = subflow->remote_key;
474 opts->csum_reqd = READ_ONCE(msk->csum_enabled);
475 opts->allow_join_id0 = mptcp_allow_join_id0(sock_net(sk));
478 * The MP_CAPABLE option is carried on the SYN, SYN/ACK, and ACK
479 * packets that start the first subflow of an MPTCP connection,
480 * as well as the first packet that carries data
483 len = TCPOLEN_MPTCP_MPC_ACK_DATA;
484 if (opts->csum_reqd) {
485 /* we need to propagate more info to csum the pseudo hdr */
486 opts->data_seq = mpext->data_seq;
487 opts->subflow_seq = mpext->subflow_seq;
488 opts->csum = mpext->csum;
489 len += TCPOLEN_MPTCP_DSS_CHECKSUM;
491 *size = ALIGN(len, 4);
493 *size = TCPOLEN_MPTCP_MPC_ACK;
496 pr_debug("subflow=%p, local_key=%llu, remote_key=%llu map_len=%d",
497 subflow, subflow->local_key, subflow->remote_key,
501 } else if (subflow->mp_join) {
502 opts->suboptions = OPTION_MPTCP_MPJ_ACK;
503 memcpy(opts->hmac, subflow->hmac, MPTCPOPT_HMAC_LEN);
504 *size = TCPOLEN_MPTCP_MPJ_ACK;
505 pr_debug("subflow=%p", subflow);
507 /* we can use the full delegate action helper only from BH context
508 * If we are in process context - sk is flushing the backlog at
509 * socket lock release time - just set the appropriate flag, will
510 * be handled by the release callback
512 if (sock_owned_by_user(sk))
513 set_bit(MPTCP_DELEGATE_ACK, &subflow->delegated_status);
515 mptcp_subflow_delegate(subflow, MPTCP_DELEGATE_ACK);
521 static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow,
522 struct sk_buff *skb, struct mptcp_ext *ext)
524 /* The write_seq value has already been incremented, so the actual
525 * sequence number for the DATA_FIN is one less.
527 u64 data_fin_tx_seq = READ_ONCE(mptcp_sk(subflow->conn)->write_seq) - 1;
529 if (!ext->use_map || !skb->len) {
530 /* RFC6824 requires a DSS mapping with specific values
531 * if DATA_FIN is set but no data payload is mapped
536 ext->data_seq = data_fin_tx_seq;
537 ext->subflow_seq = 0;
539 } else if (ext->data_seq + ext->data_len == data_fin_tx_seq) {
540 /* If there's an existing DSS mapping and it is the
541 * final mapping, DATA_FIN consumes 1 additional byte of
549 static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
550 bool snd_data_fin_enable,
552 unsigned int remaining,
553 struct mptcp_out_options *opts)
555 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
556 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
557 unsigned int dss_size = 0;
558 struct mptcp_ext *mpext;
559 unsigned int ack_size;
563 opts->csum_reqd = READ_ONCE(msk->csum_enabled);
564 mpext = skb ? mptcp_get_ext(skb) : NULL;
566 if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) {
567 unsigned int map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64;
571 map_size += TCPOLEN_MPTCP_DSS_CHECKSUM;
573 opts->ext_copy = *mpext;
576 remaining -= map_size;
578 if (skb && snd_data_fin_enable)
579 mptcp_write_data_fin(subflow, skb, &opts->ext_copy);
580 opts->suboptions = OPTION_MPTCP_DSS;
584 /* passive sockets msk will set the 'can_ack' after accept(), even
585 * if the first subflow may have the already the remote key handy
587 opts->ext_copy.use_ack = 0;
588 if (!READ_ONCE(msk->can_ack)) {
589 *size = ALIGN(dss_size, 4);
593 ack_seq = READ_ONCE(msk->ack_seq);
594 if (READ_ONCE(msk->use_64bit_ack)) {
595 ack_size = TCPOLEN_MPTCP_DSS_ACK64;
596 opts->ext_copy.data_ack = ack_seq;
597 opts->ext_copy.ack64 = 1;
599 ack_size = TCPOLEN_MPTCP_DSS_ACK32;
600 opts->ext_copy.data_ack32 = (uint32_t)ack_seq;
601 opts->ext_copy.ack64 = 0;
603 opts->ext_copy.use_ack = 1;
604 opts->suboptions = OPTION_MPTCP_DSS;
605 WRITE_ONCE(msk->old_wspace, __mptcp_space((struct sock *)msk));
607 /* Add kind/length/subtype/flag overhead if mapping is not populated */
609 ack_size += TCPOLEN_MPTCP_DSS_BASE;
611 dss_size += ack_size;
613 *size = ALIGN(dss_size, 4);
617 static u64 add_addr_generate_hmac(u64 key1, u64 key2,
618 struct mptcp_addr_info *addr)
620 u16 port = ntohs(addr->port);
621 u8 hmac[SHA256_DIGEST_SIZE];
626 if (addr->family == AF_INET) {
627 memcpy(&msg[i], &addr->addr.s_addr, 4);
630 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
631 else if (addr->family == AF_INET6) {
632 memcpy(&msg[i], &addr->addr6.s6_addr, 16);
636 msg[i++] = port >> 8;
637 msg[i++] = port & 0xFF;
639 mptcp_crypto_hmac_sha(key1, key2, msg, i, hmac);
641 return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]);
644 static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *skb,
646 unsigned int remaining,
647 struct mptcp_out_options *opts)
649 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
650 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
651 bool drop_other_suboptions = false;
652 unsigned int opt_size = *size;
657 /* add addr will strip the existing options, be sure to avoid breaking
660 if (!mptcp_pm_should_add_signal(msk) ||
661 (opts->suboptions & (OPTION_MPTCP_MPJ_ACK | OPTION_MPTCP_MPC_ACK)) ||
662 !mptcp_pm_add_addr_signal(msk, skb, opt_size, remaining, &opts->addr,
663 &echo, &port, &drop_other_suboptions))
666 if (drop_other_suboptions)
667 remaining += opt_size;
668 len = mptcp_add_addr_len(opts->addr.family, echo, port);
673 if (drop_other_suboptions) {
674 pr_debug("drop other suboptions");
675 opts->suboptions = 0;
677 /* note that e.g. DSS could have written into the memory
678 * aliased by ahmac, we must reset the field here
679 * to avoid appending the hmac even for ADD_ADDR echo
685 opts->suboptions |= OPTION_MPTCP_ADD_ADDR;
687 opts->ahmac = add_addr_generate_hmac(msk->local_key,
691 pr_debug("addr_id=%d, ahmac=%llu, echo=%d, port=%d",
692 opts->addr.id, opts->ahmac, echo, ntohs(opts->addr.port));
697 static bool mptcp_established_options_rm_addr(struct sock *sk,
699 unsigned int remaining,
700 struct mptcp_out_options *opts)
702 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
703 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
704 struct mptcp_rm_list rm_list;
707 if (!mptcp_pm_should_rm_signal(msk) ||
708 !(mptcp_pm_rm_addr_signal(msk, remaining, &rm_list)))
711 len = mptcp_rm_addr_len(&rm_list);
718 opts->suboptions |= OPTION_MPTCP_RM_ADDR;
719 opts->rm_list = rm_list;
721 for (i = 0; i < opts->rm_list.nr; i++)
722 pr_debug("rm_list_ids[%d]=%d", i, opts->rm_list.ids[i]);
727 static bool mptcp_established_options_mp_prio(struct sock *sk,
729 unsigned int remaining,
730 struct mptcp_out_options *opts)
732 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
734 /* can't send MP_PRIO with MPC, as they share the same option space:
735 * 'backup'. Also it makes no sense at all
737 if (!subflow->send_mp_prio || (opts->suboptions & OPTIONS_MPTCP_MPC))
740 /* account for the trailing 'nop' option */
741 if (remaining < TCPOLEN_MPTCP_PRIO_ALIGN)
744 *size = TCPOLEN_MPTCP_PRIO_ALIGN;
745 opts->suboptions |= OPTION_MPTCP_PRIO;
746 opts->backup = subflow->request_bkup;
748 pr_debug("prio=%d", opts->backup);
753 static noinline bool mptcp_established_options_rst(struct sock *sk, struct sk_buff *skb,
755 unsigned int remaining,
756 struct mptcp_out_options *opts)
758 const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
760 if (remaining < TCPOLEN_MPTCP_RST)
763 *size = TCPOLEN_MPTCP_RST;
764 opts->suboptions |= OPTION_MPTCP_RST;
765 opts->reset_transient = subflow->reset_transient;
766 opts->reset_reason = subflow->reset_reason;
771 static bool mptcp_established_options_fastclose(struct sock *sk,
773 unsigned int remaining,
774 struct mptcp_out_options *opts)
776 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
777 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
779 if (likely(!subflow->send_fastclose))
782 if (remaining < TCPOLEN_MPTCP_FASTCLOSE)
785 *size = TCPOLEN_MPTCP_FASTCLOSE;
786 opts->suboptions |= OPTION_MPTCP_FASTCLOSE;
787 opts->rcvr_key = msk->remote_key;
789 pr_debug("FASTCLOSE key=%llu", opts->rcvr_key);
793 static bool mptcp_established_options_mp_fail(struct sock *sk,
795 unsigned int remaining,
796 struct mptcp_out_options *opts)
798 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
800 if (likely(!subflow->send_mp_fail))
803 if (remaining < TCPOLEN_MPTCP_FAIL)
806 *size = TCPOLEN_MPTCP_FAIL;
807 opts->suboptions |= OPTION_MPTCP_FAIL;
808 opts->fail_seq = subflow->map_seq;
810 pr_debug("MP_FAIL fail_seq=%llu", opts->fail_seq);
815 bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
816 unsigned int *size, unsigned int remaining,
817 struct mptcp_out_options *opts)
819 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
820 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
821 unsigned int opt_size = 0;
825 opts->suboptions = 0;
827 if (unlikely(__mptcp_check_fallback(msk)))
830 if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) {
831 if (mptcp_established_options_fastclose(sk, &opt_size, remaining, opts) ||
832 mptcp_established_options_mp_fail(sk, &opt_size, remaining, opts)) {
834 remaining -= opt_size;
836 /* MP_RST can be used with MP_FASTCLOSE and MP_FAIL if there is room */
837 if (mptcp_established_options_rst(sk, skb, &opt_size, remaining, opts)) {
839 remaining -= opt_size;
844 snd_data_fin = mptcp_data_fin_enabled(msk);
845 if (mptcp_established_options_mp(sk, skb, snd_data_fin, &opt_size, remaining, opts))
847 else if (mptcp_established_options_dss(sk, skb, snd_data_fin, &opt_size, remaining, opts)) {
848 unsigned int mp_fail_size;
851 if (mptcp_established_options_mp_fail(sk, &mp_fail_size,
852 remaining - opt_size, opts)) {
853 *size += opt_size + mp_fail_size;
854 remaining -= opt_size - mp_fail_size;
859 /* we reserved enough space for the above options, and exceeding the
860 * TCP option space would be fatal
862 if (WARN_ON_ONCE(opt_size > remaining))
866 remaining -= opt_size;
867 if (mptcp_established_options_add_addr(sk, skb, &opt_size, remaining, opts)) {
869 remaining -= opt_size;
871 } else if (mptcp_established_options_rm_addr(sk, &opt_size, remaining, opts)) {
873 remaining -= opt_size;
877 if (mptcp_established_options_mp_prio(sk, &opt_size, remaining, opts)) {
879 remaining -= opt_size;
886 bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
887 struct mptcp_out_options *opts)
889 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
891 if (subflow_req->mp_capable) {
892 opts->suboptions = OPTION_MPTCP_MPC_SYNACK;
893 opts->sndr_key = subflow_req->local_key;
894 opts->csum_reqd = subflow_req->csum_reqd;
895 opts->allow_join_id0 = subflow_req->allow_join_id0;
896 *size = TCPOLEN_MPTCP_MPC_SYNACK;
897 pr_debug("subflow_req=%p, local_key=%llu",
898 subflow_req, subflow_req->local_key);
900 } else if (subflow_req->mp_join) {
901 opts->suboptions = OPTION_MPTCP_MPJ_SYNACK;
902 opts->backup = subflow_req->backup;
903 opts->join_id = subflow_req->local_id;
904 opts->thmac = subflow_req->thmac;
905 opts->nonce = subflow_req->local_nonce;
906 pr_debug("req=%p, bkup=%u, id=%u, thmac=%llu, nonce=%u",
907 subflow_req, opts->backup, opts->join_id,
908 opts->thmac, opts->nonce);
909 *size = TCPOLEN_MPTCP_MPJ_SYNACK;
915 static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk,
916 struct mptcp_subflow_context *subflow,
918 struct mptcp_options_received *mp_opt)
920 /* here we can process OoO, in-window pkts, only in-sequence 4th ack
921 * will make the subflow fully established
923 if (likely(subflow->fully_established)) {
924 /* on passive sockets, check for 3rd ack retransmission
925 * note that msk is always set by subflow_syn_recv_sock()
926 * for mp_join subflows
928 if (TCP_SKB_CB(skb)->seq == subflow->ssn_offset + 1 &&
929 TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq &&
930 subflow->mp_join && (mp_opt->suboptions & OPTIONS_MPTCP_MPJ) &&
931 READ_ONCE(msk->pm.server_side))
933 goto fully_established;
936 /* we must process OoO packets before the first subflow is fully
937 * established. OoO packets are instead a protocol violation
938 * for MP_JOIN subflows as the peer must not send any data
939 * before receiving the forth ack - cfr. RFC 8684 section 3.2.
941 if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) {
942 if (subflow->mp_join)
944 return subflow->mp_capable;
947 if (((mp_opt->suboptions & OPTION_MPTCP_DSS) && mp_opt->use_ack) ||
948 ((mp_opt->suboptions & OPTION_MPTCP_ADD_ADDR) && !mp_opt->echo)) {
949 /* subflows are fully established as soon as we get any
950 * additional ack, including ADD_ADDR.
952 subflow->fully_established = 1;
953 WRITE_ONCE(msk->fully_established, true);
954 goto fully_established;
957 /* If the first established packet does not contain MP_CAPABLE + data
958 * then fallback to TCP. Fallback scenarios requires a reset for
961 if (!(mp_opt->suboptions & OPTIONS_MPTCP_MPC)) {
962 if (subflow->mp_join)
964 subflow->mp_capable = 0;
966 __mptcp_do_fallback(msk);
970 if (mp_opt->deny_join_id0)
971 WRITE_ONCE(msk->pm.remote_deny_join_id0, true);
973 if (unlikely(!READ_ONCE(msk->pm.server_side)))
974 pr_warn_once("bogus mpc option on established client sk");
975 mptcp_subflow_fully_established(subflow, mp_opt);
978 /* if the subflow is not already linked into the conn_list, we can't
979 * notify the PM: this subflow is still on the listener queue
980 * and the PM possibly acquiring the subflow lock could race with
983 if (likely(subflow->pm_notified) || list_empty(&subflow->node))
986 subflow->pm_notified = 1;
987 if (subflow->mp_join) {
988 clear_3rdack_retransmission(ssk);
989 mptcp_pm_subflow_established(msk);
991 mptcp_pm_fully_established(msk, ssk, GFP_ATOMIC);
996 mptcp_subflow_reset(ssk);
1000 u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq)
1002 u32 old_seq32, cur_seq32;
1004 old_seq32 = (u32)old_seq;
1005 cur_seq32 = (u32)cur_seq;
1006 cur_seq = (old_seq & GENMASK_ULL(63, 32)) + cur_seq32;
1007 if (unlikely(cur_seq32 < old_seq32 && before(old_seq32, cur_seq32)))
1008 return cur_seq + (1LL << 32);
1010 /* reverse wrap could happen, too */
1011 if (unlikely(cur_seq32 > old_seq32 && after(old_seq32, cur_seq32)))
1012 return cur_seq - (1LL << 32);
1016 static void ack_update_msk(struct mptcp_sock *msk,
1018 struct mptcp_options_received *mp_opt)
1020 u64 new_wnd_end, new_snd_una, snd_nxt = READ_ONCE(msk->snd_nxt);
1021 struct sock *sk = (struct sock *)msk;
1024 mptcp_data_lock(sk);
1026 /* avoid ack expansion on update conflict, to reduce the risk of
1027 * wrongly expanding to a future ack sequence number, which is way
1028 * more dangerous than missing an ack
1030 old_snd_una = msk->snd_una;
1031 new_snd_una = mptcp_expand_seq(old_snd_una, mp_opt->data_ack, mp_opt->ack64);
1033 /* ACK for data not even sent yet? Ignore.*/
1034 if (unlikely(after64(new_snd_una, snd_nxt)))
1035 new_snd_una = old_snd_una;
1037 new_wnd_end = new_snd_una + tcp_sk(ssk)->snd_wnd;
1039 if (after64(new_wnd_end, msk->wnd_end))
1040 msk->wnd_end = new_wnd_end;
1042 /* this assumes mptcp_incoming_options() is invoked after tcp_ack() */
1043 if (after64(msk->wnd_end, READ_ONCE(msk->snd_nxt)))
1044 __mptcp_check_push(sk, ssk);
1046 if (after64(new_snd_una, old_snd_una)) {
1047 msk->snd_una = new_snd_una;
1048 __mptcp_data_acked(sk);
1050 mptcp_data_unlock(sk);
1052 trace_ack_update_msk(mp_opt->data_ack,
1053 old_snd_una, new_snd_una,
1054 new_wnd_end, msk->wnd_end);
1057 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit)
1059 /* Skip if DATA_FIN was already received.
1060 * If updating simultaneously with the recvmsg loop, values
1061 * should match. If they mismatch, the peer is misbehaving and
1062 * we will prefer the most recent information.
1064 if (READ_ONCE(msk->rcv_data_fin))
1067 WRITE_ONCE(msk->rcv_data_fin_seq,
1068 mptcp_expand_seq(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit));
1069 WRITE_ONCE(msk->rcv_data_fin, 1);
1074 static bool add_addr_hmac_valid(struct mptcp_sock *msk,
1075 struct mptcp_options_received *mp_opt)
1082 hmac = add_addr_generate_hmac(msk->remote_key,
1086 pr_debug("msk=%p, ahmac=%llu, mp_opt->ahmac=%llu\n",
1087 msk, (unsigned long long)hmac,
1088 (unsigned long long)mp_opt->ahmac);
1090 return hmac == mp_opt->ahmac;
1093 /* Return false if a subflow has been reset, else return true */
1094 bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
1096 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1097 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
1098 struct mptcp_options_received mp_opt;
1099 struct mptcp_ext *mpext;
1101 if (__mptcp_check_fallback(msk)) {
1102 /* Keep it simple and unconditionally trigger send data cleanup and
1103 * pending queue spooling. We will need to acquire the data lock
1104 * for more accurate checks, and once the lock is acquired, such
1105 * helpers are cheap.
1107 mptcp_data_lock(subflow->conn);
1108 if (sk_stream_memory_free(sk))
1109 __mptcp_check_push(subflow->conn, sk);
1110 __mptcp_data_acked(subflow->conn);
1111 mptcp_data_unlock(subflow->conn);
1115 mptcp_get_options(sk, skb, &mp_opt);
1117 /* The subflow can be in close state only if check_fully_established()
1118 * just sent a reset. If so, tell the caller to ignore the current packet.
1120 if (!check_fully_established(msk, sk, subflow, skb, &mp_opt))
1121 return sk->sk_state != TCP_CLOSE;
1123 if (unlikely(mp_opt.suboptions != OPTION_MPTCP_DSS)) {
1124 if ((mp_opt.suboptions & OPTION_MPTCP_FASTCLOSE) &&
1125 msk->local_key == mp_opt.rcvr_key) {
1126 WRITE_ONCE(msk->rcv_fastclose, true);
1127 mptcp_schedule_work((struct sock *)msk);
1130 if ((mp_opt.suboptions & OPTION_MPTCP_ADD_ADDR) &&
1131 add_addr_hmac_valid(msk, &mp_opt)) {
1133 mptcp_pm_add_addr_received(msk, &mp_opt.addr);
1134 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR);
1136 mptcp_pm_add_addr_echoed(msk, &mp_opt.addr);
1137 mptcp_pm_del_add_timer(msk, &mp_opt.addr, true);
1138 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD);
1141 if (mp_opt.addr.port)
1142 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_PORTADD);
1145 if (mp_opt.suboptions & OPTION_MPTCP_RM_ADDR)
1146 mptcp_pm_rm_addr_received(msk, &mp_opt.rm_list);
1148 if (mp_opt.suboptions & OPTION_MPTCP_PRIO) {
1149 mptcp_pm_mp_prio_received(sk, mp_opt.backup);
1150 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPPRIORX);
1153 if (mp_opt.suboptions & OPTION_MPTCP_FAIL) {
1154 mptcp_pm_mp_fail_received(sk, mp_opt.fail_seq);
1155 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPFAILRX);
1158 if (mp_opt.suboptions & OPTION_MPTCP_RST) {
1159 subflow->reset_seen = 1;
1160 subflow->reset_reason = mp_opt.reset_reason;
1161 subflow->reset_transient = mp_opt.reset_transient;
1164 if (!(mp_opt.suboptions & OPTION_MPTCP_DSS))
1168 /* we can't wait for recvmsg() to update the ack_seq, otherwise
1169 * monodirectional flows will stuck
1172 ack_update_msk(msk, sk, &mp_opt);
1174 /* Zero-data-length packets are dropped by the caller and not
1175 * propagated to the MPTCP layer, so the skb extension does not
1176 * need to be allocated or populated. DATA_FIN information, if
1177 * present, needs to be updated here before the skb is freed.
1179 if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) {
1180 if (mp_opt.data_fin && mp_opt.data_len == 1 &&
1181 mptcp_update_rcv_data_fin(msk, mp_opt.data_seq, mp_opt.dsn64) &&
1182 schedule_work(&msk->work))
1183 sock_hold(subflow->conn);
1188 mpext = skb_ext_add(skb, SKB_EXT_MPTCP);
1192 memset(mpext, 0, sizeof(*mpext));
1194 if (likely(mp_opt.use_map)) {
1195 if (mp_opt.mpc_map) {
1196 /* this is an MP_CAPABLE carrying MPTCP data
1197 * we know this map the first chunk of data
1199 mptcp_crypto_key_sha(subflow->remote_key, NULL,
1202 mpext->subflow_seq = 1;
1205 mpext->data_fin = 0;
1207 mpext->data_seq = mp_opt.data_seq;
1208 mpext->subflow_seq = mp_opt.subflow_seq;
1209 mpext->dsn64 = mp_opt.dsn64;
1210 mpext->data_fin = mp_opt.data_fin;
1212 mpext->data_len = mp_opt.data_len;
1214 mpext->csum_reqd = !!(mp_opt.suboptions & OPTION_MPTCP_CSUMREQD);
1216 if (mpext->csum_reqd)
1217 mpext->csum = mp_opt.csum;
1223 static void mptcp_set_rwin(const struct tcp_sock *tp)
1225 const struct sock *ssk = (const struct sock *)tp;
1226 const struct mptcp_subflow_context *subflow;
1227 struct mptcp_sock *msk;
1230 subflow = mptcp_subflow_ctx(ssk);
1231 msk = mptcp_sk(subflow->conn);
1233 ack_seq = READ_ONCE(msk->ack_seq) + tp->rcv_wnd;
1235 if (after64(ack_seq, READ_ONCE(msk->rcv_wnd_sent)))
1236 WRITE_ONCE(msk->rcv_wnd_sent, ack_seq);
1239 u16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __wsum sum)
1241 struct csum_pseudo_header header;
1244 /* cfr RFC 8684 3.3.1.:
1245 * the data sequence number used in the pseudo-header is
1246 * always the 64-bit value, irrespective of what length is used in the
1247 * DSS option itself.
1249 header.data_seq = cpu_to_be64(data_seq);
1250 header.subflow_seq = htonl(subflow_seq);
1251 header.data_len = htons(data_len);
1254 csum = csum_partial(&header, sizeof(header), sum);
1255 return (__force u16)csum_fold(csum);
1258 static u16 mptcp_make_csum(const struct mptcp_ext *mpext)
1260 return __mptcp_make_csum(mpext->data_seq, mpext->subflow_seq, mpext->data_len,
1261 ~csum_unfold(mpext->csum));
1264 void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
1265 struct mptcp_out_options *opts)
1267 if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) {
1268 const struct sock *ssk = (const struct sock *)tp;
1269 struct mptcp_subflow_context *subflow;
1271 subflow = mptcp_subflow_ctx(ssk);
1272 subflow->send_mp_fail = 0;
1274 *ptr++ = mptcp_option(MPTCPOPT_MP_FAIL,
1277 put_unaligned_be64(opts->fail_seq, ptr);
1281 /* DSS, MPC, MPJ, ADD_ADDR, FASTCLOSE and RST are mutually exclusive,
1282 * see mptcp_established_options*()
1284 if (likely(OPTION_MPTCP_DSS & opts->suboptions)) {
1285 struct mptcp_ext *mpext = &opts->ext_copy;
1286 u8 len = TCPOLEN_MPTCP_DSS_BASE;
1289 if (mpext->use_ack) {
1290 flags = MPTCP_DSS_HAS_ACK;
1292 len += TCPOLEN_MPTCP_DSS_ACK64;
1293 flags |= MPTCP_DSS_ACK64;
1295 len += TCPOLEN_MPTCP_DSS_ACK32;
1299 if (mpext->use_map) {
1300 len += TCPOLEN_MPTCP_DSS_MAP64;
1302 /* Use only 64-bit mapping flags for now, add
1303 * support for optional 32-bit mappings later.
1305 flags |= MPTCP_DSS_HAS_MAP | MPTCP_DSS_DSN64;
1306 if (mpext->data_fin)
1307 flags |= MPTCP_DSS_DATA_FIN;
1309 if (opts->csum_reqd)
1310 len += TCPOLEN_MPTCP_DSS_CHECKSUM;
1313 *ptr++ = mptcp_option(MPTCPOPT_DSS, len, 0, flags);
1315 if (mpext->use_ack) {
1317 put_unaligned_be64(mpext->data_ack, ptr);
1320 put_unaligned_be32(mpext->data_ack32, ptr);
1325 if (mpext->use_map) {
1326 put_unaligned_be64(mpext->data_seq, ptr);
1328 put_unaligned_be32(mpext->subflow_seq, ptr);
1330 if (opts->csum_reqd) {
1331 put_unaligned_be32(mpext->data_len << 16 |
1332 mptcp_make_csum(mpext), ptr);
1334 put_unaligned_be32(mpext->data_len << 16 |
1335 TCPOPT_NOP << 8 | TCPOPT_NOP, ptr);
1339 } else if (OPTIONS_MPTCP_MPC & opts->suboptions) {
1340 u8 len, flag = MPTCP_CAP_HMAC_SHA256;
1342 if (OPTION_MPTCP_MPC_SYN & opts->suboptions) {
1343 len = TCPOLEN_MPTCP_MPC_SYN;
1344 } else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions) {
1345 len = TCPOLEN_MPTCP_MPC_SYNACK;
1346 } else if (opts->data_len) {
1347 len = TCPOLEN_MPTCP_MPC_ACK_DATA;
1348 if (opts->csum_reqd)
1349 len += TCPOLEN_MPTCP_DSS_CHECKSUM;
1351 len = TCPOLEN_MPTCP_MPC_ACK;
1354 if (opts->csum_reqd)
1355 flag |= MPTCP_CAP_CHECKSUM_REQD;
1357 if (!opts->allow_join_id0)
1358 flag |= MPTCP_CAP_DENY_JOIN_ID0;
1360 *ptr++ = mptcp_option(MPTCPOPT_MP_CAPABLE, len,
1361 MPTCP_SUPPORTED_VERSION,
1364 if (!((OPTION_MPTCP_MPC_SYNACK | OPTION_MPTCP_MPC_ACK) &
1366 goto mp_capable_done;
1368 put_unaligned_be64(opts->sndr_key, ptr);
1370 if (!((OPTION_MPTCP_MPC_ACK) & opts->suboptions))
1371 goto mp_capable_done;
1373 put_unaligned_be64(opts->rcvr_key, ptr);
1375 if (!opts->data_len)
1376 goto mp_capable_done;
1378 if (opts->csum_reqd) {
1379 put_unaligned_be32(opts->data_len << 16 |
1380 __mptcp_make_csum(opts->data_seq,
1383 ~csum_unfold(opts->csum)), ptr);
1385 put_unaligned_be32(opts->data_len << 16 |
1386 TCPOPT_NOP << 8 | TCPOPT_NOP, ptr);
1390 /* MPC is additionally mutually exclusive with MP_PRIO */
1391 goto mp_capable_done;
1392 } else if (OPTIONS_MPTCP_MPJ & opts->suboptions) {
1393 if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) {
1394 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
1395 TCPOLEN_MPTCP_MPJ_SYN,
1396 opts->backup, opts->join_id);
1397 put_unaligned_be32(opts->token, ptr);
1399 put_unaligned_be32(opts->nonce, ptr);
1401 } else if (OPTION_MPTCP_MPJ_SYNACK & opts->suboptions) {
1402 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
1403 TCPOLEN_MPTCP_MPJ_SYNACK,
1404 opts->backup, opts->join_id);
1405 put_unaligned_be64(opts->thmac, ptr);
1407 put_unaligned_be32(opts->nonce, ptr);
1410 *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
1411 TCPOLEN_MPTCP_MPJ_ACK, 0, 0);
1412 memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN);
1415 } else if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) {
1416 u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
1417 u8 echo = MPTCP_ADDR_ECHO;
1419 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1420 if (opts->addr.family == AF_INET6)
1421 len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
1424 if (opts->addr.port)
1425 len += TCPOLEN_MPTCP_PORT_LEN;
1428 len += sizeof(opts->ahmac);
1432 *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
1433 len, echo, opts->addr.id);
1434 if (opts->addr.family == AF_INET) {
1435 memcpy((u8 *)ptr, (u8 *)&opts->addr.addr.s_addr, 4);
1438 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1439 else if (opts->addr.family == AF_INET6) {
1440 memcpy((u8 *)ptr, opts->addr.addr6.s6_addr, 16);
1445 if (!opts->addr.port) {
1447 put_unaligned_be64(opts->ahmac, ptr);
1451 u16 port = ntohs(opts->addr.port);
1454 u8 *bptr = (u8 *)ptr;
1456 put_unaligned_be16(port, bptr);
1458 put_unaligned_be64(opts->ahmac, bptr);
1460 put_unaligned_be16(TCPOPT_NOP << 8 |
1465 put_unaligned_be32(port << 16 |
1471 } else if (unlikely(OPTION_MPTCP_FASTCLOSE & opts->suboptions)) {
1472 /* FASTCLOSE is mutually exclusive with others except RST */
1473 *ptr++ = mptcp_option(MPTCPOPT_MP_FASTCLOSE,
1474 TCPOLEN_MPTCP_FASTCLOSE,
1476 put_unaligned_be64(opts->rcvr_key, ptr);
1479 if (OPTION_MPTCP_RST & opts->suboptions)
1482 } else if (unlikely(OPTION_MPTCP_RST & opts->suboptions)) {
1484 *ptr++ = mptcp_option(MPTCPOPT_RST,
1486 opts->reset_transient,
1487 opts->reset_reason);
1491 if (OPTION_MPTCP_PRIO & opts->suboptions) {
1492 const struct sock *ssk = (const struct sock *)tp;
1493 struct mptcp_subflow_context *subflow;
1495 subflow = mptcp_subflow_ctx(ssk);
1496 subflow->send_mp_prio = 0;
1498 *ptr++ = mptcp_option(MPTCPOPT_MP_PRIO,
1500 opts->backup, TCPOPT_NOP);
1504 if (OPTION_MPTCP_RM_ADDR & opts->suboptions) {
1507 *ptr++ = mptcp_option(MPTCPOPT_RM_ADDR,
1508 TCPOLEN_MPTCP_RM_ADDR_BASE + opts->rm_list.nr,
1509 0, opts->rm_list.ids[0]);
1511 while (i < opts->rm_list.nr) {
1512 u8 id1, id2, id3, id4;
1514 id1 = opts->rm_list.ids[i];
1515 id2 = i + 1 < opts->rm_list.nr ? opts->rm_list.ids[i + 1] : TCPOPT_NOP;
1516 id3 = i + 2 < opts->rm_list.nr ? opts->rm_list.ids[i + 2] : TCPOPT_NOP;
1517 id4 = i + 3 < opts->rm_list.nr ? opts->rm_list.ids[i + 3] : TCPOPT_NOP;
1518 put_unaligned_be32(id1 << 24 | id2 << 16 | id3 << 8 | id4, ptr);
1528 __be32 mptcp_get_reset_option(const struct sk_buff *skb)
1530 const struct mptcp_ext *ext = mptcp_get_ext(skb);
1534 flags = ext->reset_transient;
1535 reason = ext->reset_reason;
1537 return mptcp_option(MPTCPOPT_RST, TCPOLEN_MPTCP_RST,
1543 EXPORT_SYMBOL_GPL(mptcp_get_reset_option);