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 <linux/module.h>
11 #include <linux/netdevice.h>
12 #include <crypto/algapi.h>
13 #include <crypto/sha2.h>
15 #include <net/inet_common.h>
16 #include <net/inet_hashtables.h>
17 #include <net/protocol.h>
19 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
20 #include <net/ip6_route.h>
21 #include <net/transp_v6.h>
23 #include <net/mptcp.h>
24 #include <uapi/linux/mptcp.h>
28 static void mptcp_subflow_ops_undo_override(struct sock *ssk);
30 static void SUBFLOW_REQ_INC_STATS(struct request_sock *req,
31 enum linux_mptcp_mib_field field)
33 MPTCP_INC_STATS(sock_net(req_to_sk(req)), field);
36 static void subflow_req_destructor(struct request_sock *req)
38 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
40 pr_debug("subflow_req=%p", subflow_req);
43 sock_put((struct sock *)subflow_req->msk);
45 mptcp_token_destroy_request(req);
46 tcp_request_sock_ops.destructor(req);
49 static void subflow_generate_hmac(u64 key1, u64 key2, u32 nonce1, u32 nonce2,
54 put_unaligned_be32(nonce1, &msg[0]);
55 put_unaligned_be32(nonce2, &msg[4]);
57 mptcp_crypto_hmac_sha(key1, key2, msg, 8, hmac);
60 static bool mptcp_can_accept_new_subflow(const struct mptcp_sock *msk)
62 return mptcp_is_fully_established((void *)msk) &&
63 READ_ONCE(msk->pm.accept_subflow);
66 /* validate received token and create truncated hmac and nonce for SYN-ACK */
67 static void subflow_req_create_thmac(struct mptcp_subflow_request_sock *subflow_req)
69 struct mptcp_sock *msk = subflow_req->msk;
70 u8 hmac[SHA256_DIGEST_SIZE];
72 get_random_bytes(&subflow_req->local_nonce, sizeof(u32));
74 subflow_generate_hmac(msk->local_key, msk->remote_key,
75 subflow_req->local_nonce,
76 subflow_req->remote_nonce, hmac);
78 subflow_req->thmac = get_unaligned_be64(hmac);
81 static struct mptcp_sock *subflow_token_join_request(struct request_sock *req)
83 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
84 struct mptcp_sock *msk;
87 msk = mptcp_token_get_sock(subflow_req->token);
89 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINNOTOKEN);
93 local_id = mptcp_pm_get_local_id(msk, (struct sock_common *)req);
95 sock_put((struct sock *)msk);
98 subflow_req->local_id = local_id;
103 static void subflow_init_req(struct request_sock *req, const struct sock *sk_listener)
105 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
107 subflow_req->mp_capable = 0;
108 subflow_req->mp_join = 0;
109 subflow_req->msk = NULL;
110 mptcp_token_init_request(req);
113 static bool subflow_use_different_sport(struct mptcp_sock *msk, const struct sock *sk)
115 return inet_sk(sk)->inet_sport != inet_sk((struct sock *)msk)->inet_sport;
118 /* Init mptcp request socket.
120 * Returns an error code if a JOIN has failed and a TCP reset
123 static int subflow_check_req(struct request_sock *req,
124 const struct sock *sk_listener,
127 struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener);
128 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
129 struct mptcp_options_received mp_opt;
131 pr_debug("subflow_req=%p, listener=%p", subflow_req, listener);
133 #ifdef CONFIG_TCP_MD5SIG
134 /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
137 if (rcu_access_pointer(tcp_sk(sk_listener)->md5sig_info))
141 mptcp_get_options(skb, &mp_opt);
143 if (mp_opt.mp_capable) {
144 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MPCAPABLEPASSIVE);
148 } else if (mp_opt.mp_join) {
149 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINSYNRX);
152 if (mp_opt.mp_capable && listener->request_mptcp) {
153 int err, retries = 4;
155 subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq;
158 get_random_bytes(&subflow_req->local_key, sizeof(subflow_req->local_key));
159 } while (subflow_req->local_key == 0);
161 if (unlikely(req->syncookie)) {
162 mptcp_crypto_key_sha(subflow_req->local_key,
165 if (mptcp_token_exists(subflow_req->token)) {
169 subflow_req->mp_capable = 1;
174 err = mptcp_token_new_request(req);
176 subflow_req->mp_capable = 1;
177 else if (retries-- > 0)
180 } else if (mp_opt.mp_join && listener->request_mptcp) {
181 subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq;
182 subflow_req->mp_join = 1;
183 subflow_req->backup = mp_opt.backup;
184 subflow_req->remote_id = mp_opt.join_id;
185 subflow_req->token = mp_opt.token;
186 subflow_req->remote_nonce = mp_opt.nonce;
187 subflow_req->msk = subflow_token_join_request(req);
189 /* Can't fall back to TCP in this case. */
190 if (!subflow_req->msk)
193 if (subflow_use_different_sport(subflow_req->msk, sk_listener)) {
194 pr_debug("syn inet_sport=%d %d",
195 ntohs(inet_sk(sk_listener)->inet_sport),
196 ntohs(inet_sk((struct sock *)subflow_req->msk)->inet_sport));
197 if (!mptcp_pm_sport_in_anno_list(subflow_req->msk, sk_listener)) {
198 sock_put((struct sock *)subflow_req->msk);
199 mptcp_token_destroy_request(req);
200 tcp_request_sock_ops.destructor(req);
201 subflow_req->msk = NULL;
202 subflow_req->mp_join = 0;
203 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MISMATCHPORTSYNRX);
206 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINPORTSYNRX);
209 subflow_req_create_thmac(subflow_req);
211 if (unlikely(req->syncookie)) {
212 if (mptcp_can_accept_new_subflow(subflow_req->msk))
213 subflow_init_req_cookie_join_save(subflow_req, skb);
216 pr_debug("token=%u, remote_nonce=%u msk=%p", subflow_req->token,
217 subflow_req->remote_nonce, subflow_req->msk);
223 int mptcp_subflow_init_cookie_req(struct request_sock *req,
224 const struct sock *sk_listener,
227 struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener);
228 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
229 struct mptcp_options_received mp_opt;
232 subflow_init_req(req, sk_listener);
233 mptcp_get_options(skb, &mp_opt);
235 if (mp_opt.mp_capable && mp_opt.mp_join)
238 if (mp_opt.mp_capable && listener->request_mptcp) {
239 if (mp_opt.sndr_key == 0)
242 subflow_req->local_key = mp_opt.rcvr_key;
243 err = mptcp_token_new_request(req);
247 subflow_req->mp_capable = 1;
248 subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1;
249 } else if (mp_opt.mp_join && listener->request_mptcp) {
250 if (!mptcp_token_join_cookie_init_state(subflow_req, skb))
253 if (mptcp_can_accept_new_subflow(subflow_req->msk))
254 subflow_req->mp_join = 1;
256 subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1;
261 EXPORT_SYMBOL_GPL(mptcp_subflow_init_cookie_req);
263 static struct dst_entry *subflow_v4_route_req(const struct sock *sk,
266 struct request_sock *req)
268 struct dst_entry *dst;
271 tcp_rsk(req)->is_mptcp = 1;
272 subflow_init_req(req, sk);
274 dst = tcp_request_sock_ipv4_ops.route_req(sk, skb, fl, req);
278 err = subflow_check_req(req, sk, skb);
284 tcp_request_sock_ops.send_reset(sk, skb);
288 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
289 static struct dst_entry *subflow_v6_route_req(const struct sock *sk,
292 struct request_sock *req)
294 struct dst_entry *dst;
297 tcp_rsk(req)->is_mptcp = 1;
298 subflow_init_req(req, sk);
300 dst = tcp_request_sock_ipv6_ops.route_req(sk, skb, fl, req);
304 err = subflow_check_req(req, sk, skb);
310 tcp6_request_sock_ops.send_reset(sk, skb);
315 /* validate received truncated hmac and create hmac for third ACK */
316 static bool subflow_thmac_valid(struct mptcp_subflow_context *subflow)
318 u8 hmac[SHA256_DIGEST_SIZE];
321 subflow_generate_hmac(subflow->remote_key, subflow->local_key,
322 subflow->remote_nonce, subflow->local_nonce,
325 thmac = get_unaligned_be64(hmac);
326 pr_debug("subflow=%p, token=%u, thmac=%llu, subflow->thmac=%llu\n",
327 subflow, subflow->token,
328 (unsigned long long)thmac,
329 (unsigned long long)subflow->thmac);
331 return thmac == subflow->thmac;
334 void mptcp_subflow_reset(struct sock *ssk)
336 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
337 struct sock *sk = subflow->conn;
339 /* must hold: tcp_done() could drop last reference on parent */
342 tcp_set_state(ssk, TCP_CLOSE);
343 tcp_send_active_reset(ssk, GFP_ATOMIC);
345 if (!test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &mptcp_sk(sk)->flags) &&
346 schedule_work(&mptcp_sk(sk)->work))
347 return; /* worker will put sk for us */
352 static bool subflow_use_different_dport(struct mptcp_sock *msk, const struct sock *sk)
354 return inet_sk(sk)->inet_dport != inet_sk((struct sock *)msk)->inet_dport;
357 static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
359 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
360 struct mptcp_options_received mp_opt;
361 struct sock *parent = subflow->conn;
363 subflow->icsk_af_ops->sk_rx_dst_set(sk, skb);
365 if (inet_sk_state_load(parent) == TCP_SYN_SENT) {
366 inet_sk_state_store(parent, TCP_ESTABLISHED);
367 parent->sk_state_change(parent);
370 /* be sure no special action on any packet other than syn-ack */
371 if (subflow->conn_finished)
374 mptcp_propagate_sndbuf(parent, sk);
375 subflow->rel_write_seq = 1;
376 subflow->conn_finished = 1;
377 subflow->ssn_offset = TCP_SKB_CB(skb)->seq;
378 pr_debug("subflow=%p synack seq=%x", subflow, subflow->ssn_offset);
380 mptcp_get_options(skb, &mp_opt);
381 if (subflow->request_mptcp) {
382 if (!mp_opt.mp_capable) {
383 MPTCP_INC_STATS(sock_net(sk),
384 MPTCP_MIB_MPCAPABLEACTIVEFALLBACK);
385 mptcp_do_fallback(sk);
386 pr_fallback(mptcp_sk(subflow->conn));
390 subflow->mp_capable = 1;
391 subflow->can_ack = 1;
392 subflow->remote_key = mp_opt.sndr_key;
393 pr_debug("subflow=%p, remote_key=%llu", subflow,
394 subflow->remote_key);
395 mptcp_finish_connect(sk);
396 } else if (subflow->request_join) {
397 u8 hmac[SHA256_DIGEST_SIZE];
402 subflow->thmac = mp_opt.thmac;
403 subflow->remote_nonce = mp_opt.nonce;
404 pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u", subflow,
405 subflow->thmac, subflow->remote_nonce);
407 if (!subflow_thmac_valid(subflow)) {
408 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINACKMAC);
412 subflow_generate_hmac(subflow->local_key, subflow->remote_key,
413 subflow->local_nonce,
414 subflow->remote_nonce,
416 memcpy(subflow->hmac, hmac, MPTCPOPT_HMAC_LEN);
418 if (!mptcp_finish_join(sk))
421 subflow->mp_join = 1;
422 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNACKRX);
424 if (subflow_use_different_dport(mptcp_sk(parent), sk)) {
425 pr_debug("synack inet_dport=%d %d",
426 ntohs(inet_sk(sk)->inet_dport),
427 ntohs(inet_sk(parent)->inet_dport));
428 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINPORTSYNACKRX);
430 } else if (mptcp_check_fallback(sk)) {
432 mptcp_rcv_space_init(mptcp_sk(parent), sk);
437 mptcp_subflow_reset(sk);
440 struct request_sock_ops mptcp_subflow_request_sock_ops;
441 EXPORT_SYMBOL_GPL(mptcp_subflow_request_sock_ops);
442 static struct tcp_request_sock_ops subflow_request_sock_ipv4_ops;
444 static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb)
446 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
448 pr_debug("subflow=%p", subflow);
450 /* Never answer to SYNs sent to broadcast or multicast */
451 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
454 return tcp_conn_request(&mptcp_subflow_request_sock_ops,
455 &subflow_request_sock_ipv4_ops,
462 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
463 static struct tcp_request_sock_ops subflow_request_sock_ipv6_ops;
464 static struct inet_connection_sock_af_ops subflow_v6_specific;
465 static struct inet_connection_sock_af_ops subflow_v6m_specific;
466 static struct proto tcpv6_prot_override;
468 static int subflow_v6_conn_request(struct sock *sk, struct sk_buff *skb)
470 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
472 pr_debug("subflow=%p", subflow);
474 if (skb->protocol == htons(ETH_P_IP))
475 return subflow_v4_conn_request(sk, skb);
477 if (!ipv6_unicast_destination(skb))
480 return tcp_conn_request(&mptcp_subflow_request_sock_ops,
481 &subflow_request_sock_ipv6_ops, sk, skb);
485 return 0; /* don't send reset */
489 /* validate hmac received in third ACK */
490 static bool subflow_hmac_valid(const struct request_sock *req,
491 const struct mptcp_options_received *mp_opt)
493 const struct mptcp_subflow_request_sock *subflow_req;
494 u8 hmac[SHA256_DIGEST_SIZE];
495 struct mptcp_sock *msk;
497 subflow_req = mptcp_subflow_rsk(req);
498 msk = subflow_req->msk;
502 subflow_generate_hmac(msk->remote_key, msk->local_key,
503 subflow_req->remote_nonce,
504 subflow_req->local_nonce, hmac);
506 return !crypto_memneq(hmac, mp_opt->hmac, MPTCPOPT_HMAC_LEN);
509 static void mptcp_sock_destruct(struct sock *sk)
511 /* if new mptcp socket isn't accepted, it is free'd
512 * from the tcp listener sockets request queue, linked
513 * from req->sk. The tcp socket is released.
514 * This calls the ULP release function which will
515 * also remove the mptcp socket, via
516 * sock_put(ctx->conn).
518 * Problem is that the mptcp socket will be in
519 * ESTABLISHED state and will not have the SOCK_DEAD flag.
520 * Both result in warnings from inet_sock_destruct.
523 if (sk->sk_state == TCP_ESTABLISHED) {
524 sk->sk_state = TCP_CLOSE;
525 WARN_ON_ONCE(sk->sk_socket);
529 mptcp_destroy_common(mptcp_sk(sk));
530 inet_sock_destruct(sk);
533 static void mptcp_force_close(struct sock *sk)
535 inet_sk_state_store(sk, TCP_CLOSE);
536 sk_common_release(sk);
539 static void subflow_ulp_fallback(struct sock *sk,
540 struct mptcp_subflow_context *old_ctx)
542 struct inet_connection_sock *icsk = inet_csk(sk);
544 mptcp_subflow_tcp_fallback(sk, old_ctx);
545 icsk->icsk_ulp_ops = NULL;
546 rcu_assign_pointer(icsk->icsk_ulp_data, NULL);
547 tcp_sk(sk)->is_mptcp = 0;
549 mptcp_subflow_ops_undo_override(sk);
552 static void subflow_drop_ctx(struct sock *ssk)
554 struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(ssk);
559 subflow_ulp_fallback(ssk, ctx);
566 void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,
567 struct mptcp_options_received *mp_opt)
569 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
571 subflow->remote_key = mp_opt->sndr_key;
572 subflow->fully_established = 1;
573 subflow->can_ack = 1;
574 WRITE_ONCE(msk->fully_established, true);
577 static struct sock *subflow_syn_recv_sock(const struct sock *sk,
579 struct request_sock *req,
580 struct dst_entry *dst,
581 struct request_sock *req_unhash,
584 struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk);
585 struct mptcp_subflow_request_sock *subflow_req;
586 struct mptcp_options_received mp_opt;
587 bool fallback, fallback_is_fatal;
588 struct sock *new_msk = NULL;
591 pr_debug("listener=%p, req=%p, conn=%p", listener, req, listener->conn);
593 /* After child creation we must look for 'mp_capable' even when options
596 mp_opt.mp_capable = 0;
598 /* hopefully temporary handling for MP_JOIN+syncookie */
599 subflow_req = mptcp_subflow_rsk(req);
600 fallback_is_fatal = tcp_rsk(req)->is_mptcp && subflow_req->mp_join;
601 fallback = !tcp_rsk(req)->is_mptcp;
605 /* if the sk is MP_CAPABLE, we try to fetch the client key */
606 if (subflow_req->mp_capable) {
607 if (TCP_SKB_CB(skb)->seq != subflow_req->ssn_offset + 1) {
608 /* here we can receive and accept an in-window,
609 * out-of-order pkt, which will not carry the MP_CAPABLE
610 * opt even on mptcp enabled paths
615 mptcp_get_options(skb, &mp_opt);
616 if (!mp_opt.mp_capable) {
622 new_msk = mptcp_sk_clone(listener->conn, &mp_opt, req);
625 } else if (subflow_req->mp_join) {
626 mptcp_get_options(skb, &mp_opt);
627 if (!mp_opt.mp_join || !subflow_hmac_valid(req, &mp_opt) ||
628 !mptcp_can_accept_new_subflow(subflow_req->msk)) {
629 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC);
635 child = listener->icsk_af_ops->syn_recv_sock(sk, skb, req, dst,
636 req_unhash, own_req);
638 if (child && *own_req) {
639 struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(child);
641 tcp_rsk(req)->drop_req = false;
643 /* we need to fallback on ctx allocation failure and on pre-reqs
644 * checking above. In the latter scenario we additionally need
645 * to reset the context to non MPTCP status.
647 if (!ctx || fallback) {
648 if (fallback_is_fatal)
651 subflow_drop_ctx(child);
655 if (ctx->mp_capable) {
656 /* this can't race with mptcp_close(), as the msk is
657 * not yet exposted to user-space
659 inet_sk_state_store((void *)new_msk, TCP_ESTABLISHED);
661 /* record the newly created socket as the first msk
662 * subflow, but don't link it yet into conn_list
664 WRITE_ONCE(mptcp_sk(new_msk)->first, child);
666 /* new mpc subflow takes ownership of the newly
667 * created mptcp socket
669 new_msk->sk_destruct = mptcp_sock_destruct;
670 mptcp_pm_new_connection(mptcp_sk(new_msk), child, 1);
671 mptcp_token_accept(subflow_req, mptcp_sk(new_msk));
675 /* with OoO packets we can reach here without ingress
678 if (mp_opt.mp_capable)
679 mptcp_subflow_fully_established(ctx, &mp_opt);
680 } else if (ctx->mp_join) {
681 struct mptcp_sock *owner;
683 owner = subflow_req->msk;
687 /* move the msk reference ownership to the subflow */
688 subflow_req->msk = NULL;
689 ctx->conn = (struct sock *)owner;
690 if (!mptcp_finish_join(child))
693 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKRX);
694 tcp_rsk(req)->drop_req = true;
696 if (subflow_use_different_sport(owner, sk)) {
697 pr_debug("ack inet_sport=%d %d",
698 ntohs(inet_sk(sk)->inet_sport),
699 ntohs(inet_sk((struct sock *)owner)->inet_sport));
700 if (!mptcp_pm_sport_in_anno_list(owner, sk)) {
701 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MISMATCHPORTACKRX);
704 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINPORTACKRX);
710 /* dispose of the left over mptcp master, if any */
711 if (unlikely(new_msk))
712 mptcp_force_close(new_msk);
714 /* check for expected invariant - should never trigger, just help
715 * catching eariler subtle bugs
717 WARN_ON_ONCE(child && *own_req && tcp_sk(child)->is_mptcp &&
718 (!mptcp_subflow_ctx(child) ||
719 !mptcp_subflow_ctx(child)->conn));
723 subflow_drop_ctx(child);
724 tcp_rsk(req)->drop_req = true;
725 inet_csk_prepare_for_destroy_sock(child);
727 req->rsk_ops->send_reset(sk, skb);
729 /* The last child reference will be released by the caller */
733 static struct inet_connection_sock_af_ops subflow_specific;
734 static struct proto tcp_prot_override;
736 enum mapping_status {
744 static u64 expand_seq(u64 old_seq, u16 old_data_len, u64 seq)
746 if ((u32)seq == (u32)old_seq)
749 /* Assume map covers data not mapped yet. */
750 return seq | ((old_seq + old_data_len + 1) & GENMASK_ULL(63, 32));
753 static void warn_bad_map(struct mptcp_subflow_context *subflow, u32 ssn)
755 WARN_ONCE(1, "Bad mapping: ssn=%d map_seq=%d map_data_len=%d",
756 ssn, subflow->map_subflow_seq, subflow->map_data_len);
759 static bool skb_is_fully_mapped(struct sock *ssk, struct sk_buff *skb)
761 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
762 unsigned int skb_consumed;
764 skb_consumed = tcp_sk(ssk)->copied_seq - TCP_SKB_CB(skb)->seq;
765 if (WARN_ON_ONCE(skb_consumed >= skb->len))
768 return skb->len - skb_consumed <= subflow->map_data_len -
769 mptcp_subflow_get_map_offset(subflow);
772 static bool validate_mapping(struct sock *ssk, struct sk_buff *skb)
774 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
775 u32 ssn = tcp_sk(ssk)->copied_seq - subflow->ssn_offset;
777 if (unlikely(before(ssn, subflow->map_subflow_seq))) {
778 /* Mapping covers data later in the subflow stream,
779 * currently unsupported.
781 warn_bad_map(subflow, ssn);
784 if (unlikely(!before(ssn, subflow->map_subflow_seq +
785 subflow->map_data_len))) {
786 /* Mapping does covers past subflow data, invalid */
787 warn_bad_map(subflow, ssn + skb->len);
793 static enum mapping_status get_mapping_status(struct sock *ssk,
794 struct mptcp_sock *msk)
796 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
797 struct mptcp_ext *mpext;
802 skb = skb_peek(&ssk->sk_receive_queue);
804 return MAPPING_EMPTY;
806 if (mptcp_check_fallback(ssk))
807 return MAPPING_DUMMY;
809 mpext = mptcp_get_ext(skb);
810 if (!mpext || !mpext->use_map) {
811 if (!subflow->map_valid && !skb->len) {
812 /* the TCP stack deliver 0 len FIN pkt to the receive
813 * queue, that is the only 0len pkts ever expected here,
814 * and we can admit no mapping only for 0 len pkts
816 if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN))
817 WARN_ONCE(1, "0len seq %d:%d flags %x",
818 TCP_SKB_CB(skb)->seq,
819 TCP_SKB_CB(skb)->end_seq,
820 TCP_SKB_CB(skb)->tcp_flags);
821 sk_eat_skb(ssk, skb);
822 return MAPPING_EMPTY;
825 if (!subflow->map_valid)
826 return MAPPING_INVALID;
831 pr_debug("seq=%llu is64=%d ssn=%u data_len=%u data_fin=%d",
832 mpext->data_seq, mpext->dsn64, mpext->subflow_seq,
833 mpext->data_len, mpext->data_fin);
835 data_len = mpext->data_len;
837 pr_err("Infinite mapping not handled");
838 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPRX);
839 return MAPPING_INVALID;
842 if (mpext->data_fin == 1) {
844 bool updated = mptcp_update_rcv_data_fin(msk, mpext->data_seq,
846 pr_debug("DATA_FIN with no payload seq=%llu", mpext->data_seq);
847 if (subflow->map_valid) {
848 /* A DATA_FIN might arrive in a DSS
849 * option before the previous mapping
850 * has been fully consumed. Continue
851 * handling the existing mapping.
853 skb_ext_del(skb, SKB_EXT_MPTCP);
856 if (updated && schedule_work(&msk->work))
857 sock_hold((struct sock *)msk);
859 return MAPPING_DATA_FIN;
862 u64 data_fin_seq = mpext->data_seq + data_len - 1;
864 /* If mpext->data_seq is a 32-bit value, data_fin_seq
865 * must also be limited to 32 bits.
868 data_fin_seq &= GENMASK_ULL(31, 0);
870 mptcp_update_rcv_data_fin(msk, data_fin_seq, mpext->dsn64);
871 pr_debug("DATA_FIN with mapping seq=%llu dsn64=%d",
872 data_fin_seq, mpext->dsn64);
875 /* Adjust for DATA_FIN using 1 byte of sequence space */
880 map_seq = expand_seq(subflow->map_seq, subflow->map_data_len,
882 pr_debug("expanded seq=%llu", subflow->map_seq);
884 map_seq = mpext->data_seq;
886 WRITE_ONCE(mptcp_sk(subflow->conn)->use_64bit_ack, !!mpext->dsn64);
888 if (subflow->map_valid) {
889 /* Allow replacing only with an identical map */
890 if (subflow->map_seq == map_seq &&
891 subflow->map_subflow_seq == mpext->subflow_seq &&
892 subflow->map_data_len == data_len) {
893 skb_ext_del(skb, SKB_EXT_MPTCP);
897 /* If this skb data are fully covered by the current mapping,
898 * the new map would need caching, which is not supported
900 if (skb_is_fully_mapped(ssk, skb)) {
901 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DSSNOMATCH);
902 return MAPPING_INVALID;
905 /* will validate the next map after consuming the current one */
909 subflow->map_seq = map_seq;
910 subflow->map_subflow_seq = mpext->subflow_seq;
911 subflow->map_data_len = data_len;
912 subflow->map_valid = 1;
913 subflow->mpc_map = mpext->mpc_map;
914 pr_debug("new map seq=%llu subflow_seq=%u data_len=%u",
915 subflow->map_seq, subflow->map_subflow_seq,
916 subflow->map_data_len);
919 /* we revalidate valid mapping on new skb, because we must ensure
920 * the current skb is completely covered by the available mapping
922 if (!validate_mapping(ssk, skb))
923 return MAPPING_INVALID;
925 skb_ext_del(skb, SKB_EXT_MPTCP);
929 static void mptcp_subflow_discard_data(struct sock *ssk, struct sk_buff *skb,
932 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
933 bool fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
936 incr = limit >= skb->len ? skb->len + fin : limit;
938 pr_debug("discarding=%d len=%d seq=%d", incr, skb->len,
939 subflow->map_subflow_seq);
940 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DUPDATA);
941 tcp_sk(ssk)->copied_seq += incr;
942 if (!before(tcp_sk(ssk)->copied_seq, TCP_SKB_CB(skb)->end_seq))
943 sk_eat_skb(ssk, skb);
944 if (mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len)
945 subflow->map_valid = 0;
948 /* sched mptcp worker to remove the subflow if no more data is pending */
949 static void subflow_sched_work_if_closed(struct mptcp_sock *msk, struct sock *ssk)
951 struct sock *sk = (struct sock *)msk;
953 if (likely(ssk->sk_state != TCP_CLOSE))
956 if (skb_queue_empty(&ssk->sk_receive_queue) &&
957 !test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags)) {
959 if (!schedule_work(&msk->work))
964 static bool subflow_check_data_avail(struct sock *ssk)
966 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
967 enum mapping_status status;
968 struct mptcp_sock *msk;
971 pr_debug("msk=%p ssk=%p data_avail=%d skb=%p", subflow->conn, ssk,
972 subflow->data_avail, skb_peek(&ssk->sk_receive_queue));
973 if (!skb_peek(&ssk->sk_receive_queue))
974 subflow->data_avail = 0;
975 if (subflow->data_avail)
978 msk = mptcp_sk(subflow->conn);
983 status = get_mapping_status(ssk, msk);
984 pr_debug("msk=%p ssk=%p status=%d", msk, ssk, status);
985 if (status == MAPPING_INVALID) {
986 ssk->sk_err = EBADMSG;
989 if (status == MAPPING_DUMMY) {
990 __mptcp_do_fallback(msk);
991 skb = skb_peek(&ssk->sk_receive_queue);
992 subflow->map_valid = 1;
993 subflow->map_seq = READ_ONCE(msk->ack_seq);
994 subflow->map_data_len = skb->len;
995 subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq -
997 subflow->data_avail = MPTCP_SUBFLOW_DATA_AVAIL;
1001 if (status != MAPPING_OK)
1004 skb = skb_peek(&ssk->sk_receive_queue);
1005 if (WARN_ON_ONCE(!skb))
1008 /* if msk lacks the remote key, this subflow must provide an
1009 * MP_CAPABLE-based mapping
1011 if (unlikely(!READ_ONCE(msk->can_ack))) {
1012 if (!subflow->mpc_map) {
1013 ssk->sk_err = EBADMSG;
1016 WRITE_ONCE(msk->remote_key, subflow->remote_key);
1017 WRITE_ONCE(msk->ack_seq, subflow->map_seq);
1018 WRITE_ONCE(msk->can_ack, true);
1021 old_ack = READ_ONCE(msk->ack_seq);
1022 ack_seq = mptcp_subflow_get_mapped_dsn(subflow);
1023 pr_debug("msk ack_seq=%llx subflow ack_seq=%llx", old_ack,
1025 if (ack_seq == old_ack) {
1026 subflow->data_avail = MPTCP_SUBFLOW_DATA_AVAIL;
1028 } else if (after64(ack_seq, old_ack)) {
1029 subflow->data_avail = MPTCP_SUBFLOW_OOO_DATA;
1033 /* only accept in-sequence mapping. Old values are spurious
1036 mptcp_subflow_discard_data(ssk, skb, old_ack - ack_seq);
1041 subflow_sched_work_if_closed(msk, ssk);
1044 /* fatal protocol error, close the socket */
1045 /* This barrier is coupled with smp_rmb() in tcp_poll() */
1047 ssk->sk_error_report(ssk);
1048 tcp_set_state(ssk, TCP_CLOSE);
1049 tcp_send_active_reset(ssk, GFP_ATOMIC);
1050 subflow->data_avail = 0;
1054 bool mptcp_subflow_data_available(struct sock *sk)
1056 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1058 /* check if current mapping is still valid */
1059 if (subflow->map_valid &&
1060 mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len) {
1061 subflow->map_valid = 0;
1062 subflow->data_avail = 0;
1064 pr_debug("Done with mapping: seq=%u data_len=%u",
1065 subflow->map_subflow_seq,
1066 subflow->map_data_len);
1069 return subflow_check_data_avail(sk);
1072 /* If ssk has an mptcp parent socket, use the mptcp rcvbuf occupancy,
1075 * In mptcp, rwin is about the mptcp-level connection data.
1077 * Data that is still on the ssk rx queue can thus be ignored,
1078 * as far as mptcp peer is concerened that data is still inflight.
1079 * DSS ACK is updated when skb is moved to the mptcp rx queue.
1081 void mptcp_space(const struct sock *ssk, int *space, int *full_space)
1083 const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1084 const struct sock *sk = subflow->conn;
1086 *space = __mptcp_space(sk);
1087 *full_space = tcp_full_space(sk);
1090 static void subflow_data_ready(struct sock *sk)
1092 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1093 u16 state = 1 << inet_sk_state_load(sk);
1094 struct sock *parent = subflow->conn;
1095 struct mptcp_sock *msk;
1097 msk = mptcp_sk(parent);
1098 if (state & TCPF_LISTEN) {
1099 /* MPJ subflow are removed from accept queue before reaching here,
1100 * avoid stray wakeups
1102 if (reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue))
1105 set_bit(MPTCP_DATA_READY, &msk->flags);
1106 parent->sk_data_ready(parent);
1110 WARN_ON_ONCE(!__mptcp_check_fallback(msk) && !subflow->mp_capable &&
1111 !subflow->mp_join && !(state & TCPF_CLOSE));
1113 if (mptcp_subflow_data_available(sk))
1114 mptcp_data_ready(parent, sk);
1117 static void subflow_write_space(struct sock *ssk)
1119 struct sock *sk = mptcp_subflow_ctx(ssk)->conn;
1121 mptcp_propagate_sndbuf(sk, ssk);
1122 mptcp_write_space(sk);
1125 void __mptcp_error_report(struct sock *sk)
1127 struct mptcp_subflow_context *subflow;
1128 struct mptcp_sock *msk = mptcp_sk(sk);
1130 mptcp_for_each_subflow(msk, subflow) {
1131 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
1132 int err = sock_error(ssk);
1137 /* only propagate errors on fallen-back sockets or
1140 if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(msk))
1143 inet_sk_state_store(sk, inet_sk_state_load(ssk));
1146 /* This barrier is coupled with smp_rmb() in mptcp_poll() */
1148 sk->sk_error_report(sk);
1153 static void subflow_error_report(struct sock *ssk)
1155 struct sock *sk = mptcp_subflow_ctx(ssk)->conn;
1157 mptcp_data_lock(sk);
1158 if (!sock_owned_by_user(sk))
1159 __mptcp_error_report(sk);
1161 set_bit(MPTCP_ERROR_REPORT, &mptcp_sk(sk)->flags);
1162 mptcp_data_unlock(sk);
1165 static struct inet_connection_sock_af_ops *
1166 subflow_default_af_ops(struct sock *sk)
1168 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1169 if (sk->sk_family == AF_INET6)
1170 return &subflow_v6_specific;
1172 return &subflow_specific;
1175 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1176 void mptcpv6_handle_mapped(struct sock *sk, bool mapped)
1178 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1179 struct inet_connection_sock *icsk = inet_csk(sk);
1180 struct inet_connection_sock_af_ops *target;
1182 target = mapped ? &subflow_v6m_specific : subflow_default_af_ops(sk);
1184 pr_debug("subflow=%p family=%d ops=%p target=%p mapped=%d",
1185 subflow, sk->sk_family, icsk->icsk_af_ops, target, mapped);
1187 if (likely(icsk->icsk_af_ops == target))
1190 subflow->icsk_af_ops = icsk->icsk_af_ops;
1191 icsk->icsk_af_ops = target;
1195 void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
1196 struct sockaddr_storage *addr,
1197 unsigned short family)
1199 memset(addr, 0, sizeof(*addr));
1200 addr->ss_family = family;
1201 if (addr->ss_family == AF_INET) {
1202 struct sockaddr_in *in_addr = (struct sockaddr_in *)addr;
1204 if (info->family == AF_INET)
1205 in_addr->sin_addr = info->addr;
1206 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1207 else if (ipv6_addr_v4mapped(&info->addr6))
1208 in_addr->sin_addr.s_addr = info->addr6.s6_addr32[3];
1210 in_addr->sin_port = info->port;
1212 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1213 else if (addr->ss_family == AF_INET6) {
1214 struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)addr;
1216 if (info->family == AF_INET)
1217 ipv6_addr_set_v4mapped(info->addr.s_addr,
1218 &in6_addr->sin6_addr);
1220 in6_addr->sin6_addr = info->addr6;
1221 in6_addr->sin6_port = info->port;
1226 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
1227 const struct mptcp_addr_info *remote)
1229 struct mptcp_sock *msk = mptcp_sk(sk);
1230 struct mptcp_subflow_context *subflow;
1231 struct sockaddr_storage addr;
1232 int remote_id = remote->id;
1233 int local_id = loc->id;
1240 if (!mptcp_is_fully_established(sk))
1243 err = mptcp_subflow_create_socket(sk, &sf);
1248 subflow = mptcp_subflow_ctx(ssk);
1250 get_random_bytes(&subflow->local_nonce, sizeof(u32));
1251 } while (!subflow->local_nonce);
1254 err = mptcp_pm_get_local_id(msk, (struct sock_common *)ssk);
1261 subflow->remote_key = msk->remote_key;
1262 subflow->local_key = msk->local_key;
1263 subflow->token = msk->token;
1264 mptcp_info2sockaddr(loc, &addr, ssk->sk_family);
1266 addrlen = sizeof(struct sockaddr_in);
1267 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1268 if (addr.ss_family == AF_INET6)
1269 addrlen = sizeof(struct sockaddr_in6);
1271 ssk->sk_bound_dev_if = loc->ifindex;
1272 err = kernel_bind(sf, (struct sockaddr *)&addr, addrlen);
1276 mptcp_crypto_key_sha(subflow->remote_key, &remote_token, NULL);
1277 pr_debug("msk=%p remote_token=%u local_id=%d remote_id=%d", msk,
1278 remote_token, local_id, remote_id);
1279 subflow->remote_token = remote_token;
1280 subflow->local_id = local_id;
1281 subflow->remote_id = remote_id;
1282 subflow->request_join = 1;
1283 subflow->request_bkup = !!(loc->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
1284 mptcp_info2sockaddr(remote, &addr, ssk->sk_family);
1286 mptcp_add_pending_subflow(msk, subflow);
1287 err = kernel_connect(sf, (struct sockaddr *)&addr, addrlen, O_NONBLOCK);
1288 if (err && err != -EINPROGRESS)
1291 /* discard the subflow socket */
1292 mptcp_sock_graft(ssk, sk->sk_socket);
1293 iput(SOCK_INODE(sf));
1297 spin_lock_bh(&msk->join_list_lock);
1298 list_del(&subflow->node);
1299 spin_unlock_bh(&msk->join_list_lock);
1300 sock_put(mptcp_subflow_tcp_sock(subflow));
1303 subflow->disposable = 1;
1308 static void mptcp_attach_cgroup(struct sock *parent, struct sock *child)
1310 #ifdef CONFIG_SOCK_CGROUP_DATA
1311 struct sock_cgroup_data *parent_skcd = &parent->sk_cgrp_data,
1312 *child_skcd = &child->sk_cgrp_data;
1314 /* only the additional subflows created by kworkers have to be modified */
1315 if (cgroup_id(sock_cgroup_ptr(parent_skcd)) !=
1316 cgroup_id(sock_cgroup_ptr(child_skcd))) {
1318 struct mem_cgroup *memcg = parent->sk_memcg;
1320 mem_cgroup_sk_free(child);
1321 if (memcg && css_tryget(&memcg->css))
1322 child->sk_memcg = memcg;
1323 #endif /* CONFIG_MEMCG */
1325 cgroup_sk_free(child_skcd);
1326 *child_skcd = *parent_skcd;
1327 cgroup_sk_clone(child_skcd);
1329 #endif /* CONFIG_SOCK_CGROUP_DATA */
1332 static void mptcp_subflow_ops_override(struct sock *ssk)
1334 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1335 if (ssk->sk_prot == &tcpv6_prot)
1336 ssk->sk_prot = &tcpv6_prot_override;
1339 ssk->sk_prot = &tcp_prot_override;
1342 static void mptcp_subflow_ops_undo_override(struct sock *ssk)
1344 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1345 if (ssk->sk_prot == &tcpv6_prot_override)
1346 ssk->sk_prot = &tcpv6_prot;
1349 ssk->sk_prot = &tcp_prot;
1351 int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock)
1353 struct mptcp_subflow_context *subflow;
1354 struct net *net = sock_net(sk);
1358 /* un-accepted server sockets can reach here - on bad configuration
1359 * bail early to avoid greater trouble later
1361 if (unlikely(!sk->sk_socket))
1364 err = sock_create_kern(net, sk->sk_family, SOCK_STREAM, IPPROTO_TCP,
1371 /* the newly created socket has to be in the same cgroup as its parent */
1372 mptcp_attach_cgroup(sk, sf->sk);
1374 /* kernel sockets do not by default acquire net ref, but TCP timer
1377 sf->sk->sk_net_refcnt = 1;
1379 #ifdef CONFIG_PROC_FS
1380 this_cpu_add(*net->core.sock_inuse, 1);
1382 err = tcp_set_ulp(sf->sk, "mptcp");
1383 release_sock(sf->sk);
1390 /* the newly created socket really belongs to the owning MPTCP master
1391 * socket, even if for additional subflows the allocation is performed
1392 * by a kernel workqueue. Adjust inode references, so that the
1393 * procfs/diag interaces really show this one belonging to the correct
1396 SOCK_INODE(sf)->i_ino = SOCK_INODE(sk->sk_socket)->i_ino;
1397 SOCK_INODE(sf)->i_uid = SOCK_INODE(sk->sk_socket)->i_uid;
1398 SOCK_INODE(sf)->i_gid = SOCK_INODE(sk->sk_socket)->i_gid;
1400 subflow = mptcp_subflow_ctx(sf->sk);
1401 pr_debug("subflow=%p", subflow);
1406 mptcp_subflow_ops_override(sf->sk);
1411 static struct mptcp_subflow_context *subflow_create_ctx(struct sock *sk,
1414 struct inet_connection_sock *icsk = inet_csk(sk);
1415 struct mptcp_subflow_context *ctx;
1417 ctx = kzalloc(sizeof(*ctx), priority);
1421 rcu_assign_pointer(icsk->icsk_ulp_data, ctx);
1422 INIT_LIST_HEAD(&ctx->node);
1423 INIT_LIST_HEAD(&ctx->delegated_node);
1425 pr_debug("subflow=%p", ctx);
1432 static void __subflow_state_change(struct sock *sk)
1434 struct socket_wq *wq;
1437 wq = rcu_dereference(sk->sk_wq);
1438 if (skwq_has_sleeper(wq))
1439 wake_up_interruptible_all(&wq->wait);
1443 static bool subflow_is_done(const struct sock *sk)
1445 return sk->sk_shutdown & RCV_SHUTDOWN || sk->sk_state == TCP_CLOSE;
1448 static void subflow_state_change(struct sock *sk)
1450 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1451 struct sock *parent = subflow->conn;
1453 __subflow_state_change(sk);
1455 if (subflow_simultaneous_connect(sk)) {
1456 mptcp_propagate_sndbuf(parent, sk);
1457 mptcp_do_fallback(sk);
1458 mptcp_rcv_space_init(mptcp_sk(parent), sk);
1459 pr_fallback(mptcp_sk(parent));
1460 subflow->conn_finished = 1;
1461 if (inet_sk_state_load(parent) == TCP_SYN_SENT) {
1462 inet_sk_state_store(parent, TCP_ESTABLISHED);
1463 parent->sk_state_change(parent);
1467 /* as recvmsg() does not acquire the subflow socket for ssk selection
1468 * a fin packet carrying a DSS can be unnoticed if we don't trigger
1469 * the data available machinery here.
1471 if (mptcp_subflow_data_available(sk))
1472 mptcp_data_ready(parent, sk);
1474 subflow_sched_work_if_closed(mptcp_sk(parent), sk);
1476 if (__mptcp_check_fallback(mptcp_sk(parent)) &&
1477 !subflow->rx_eof && subflow_is_done(sk)) {
1478 subflow->rx_eof = 1;
1479 mptcp_subflow_eof(parent);
1483 static int subflow_ulp_init(struct sock *sk)
1485 struct inet_connection_sock *icsk = inet_csk(sk);
1486 struct mptcp_subflow_context *ctx;
1487 struct tcp_sock *tp = tcp_sk(sk);
1490 /* disallow attaching ULP to a socket unless it has been
1491 * created with sock_create_kern()
1493 if (!sk->sk_kern_sock) {
1498 ctx = subflow_create_ctx(sk, GFP_KERNEL);
1504 pr_debug("subflow=%p, family=%d", ctx, sk->sk_family);
1507 ctx->icsk_af_ops = icsk->icsk_af_ops;
1508 icsk->icsk_af_ops = subflow_default_af_ops(sk);
1509 ctx->tcp_data_ready = sk->sk_data_ready;
1510 ctx->tcp_state_change = sk->sk_state_change;
1511 ctx->tcp_write_space = sk->sk_write_space;
1512 ctx->tcp_error_report = sk->sk_error_report;
1513 sk->sk_data_ready = subflow_data_ready;
1514 sk->sk_write_space = subflow_write_space;
1515 sk->sk_state_change = subflow_state_change;
1516 sk->sk_error_report = subflow_error_report;
1521 static void subflow_ulp_release(struct sock *ssk)
1523 struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(ssk);
1524 bool release = true;
1532 /* if the msk has been orphaned, keep the ctx
1533 * alive, will be freed by __mptcp_close_ssk(),
1534 * when the subflow is still unaccepted
1536 release = ctx->disposable || list_empty(&ctx->node);
1540 mptcp_subflow_ops_undo_override(ssk);
1542 kfree_rcu(ctx, rcu);
1545 static void subflow_ulp_clone(const struct request_sock *req,
1547 const gfp_t priority)
1549 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
1550 struct mptcp_subflow_context *old_ctx = mptcp_subflow_ctx(newsk);
1551 struct mptcp_subflow_context *new_ctx;
1553 if (!tcp_rsk(req)->is_mptcp ||
1554 (!subflow_req->mp_capable && !subflow_req->mp_join)) {
1555 subflow_ulp_fallback(newsk, old_ctx);
1559 new_ctx = subflow_create_ctx(newsk, priority);
1561 subflow_ulp_fallback(newsk, old_ctx);
1565 new_ctx->conn_finished = 1;
1566 new_ctx->icsk_af_ops = old_ctx->icsk_af_ops;
1567 new_ctx->tcp_data_ready = old_ctx->tcp_data_ready;
1568 new_ctx->tcp_state_change = old_ctx->tcp_state_change;
1569 new_ctx->tcp_write_space = old_ctx->tcp_write_space;
1570 new_ctx->tcp_error_report = old_ctx->tcp_error_report;
1571 new_ctx->rel_write_seq = 1;
1572 new_ctx->tcp_sock = newsk;
1574 if (subflow_req->mp_capable) {
1575 /* see comments in subflow_syn_recv_sock(), MPTCP connection
1576 * is fully established only after we receive the remote key
1578 new_ctx->mp_capable = 1;
1579 new_ctx->local_key = subflow_req->local_key;
1580 new_ctx->token = subflow_req->token;
1581 new_ctx->ssn_offset = subflow_req->ssn_offset;
1582 new_ctx->idsn = subflow_req->idsn;
1583 } else if (subflow_req->mp_join) {
1584 new_ctx->ssn_offset = subflow_req->ssn_offset;
1585 new_ctx->mp_join = 1;
1586 new_ctx->fully_established = 1;
1587 new_ctx->backup = subflow_req->backup;
1588 new_ctx->local_id = subflow_req->local_id;
1589 new_ctx->remote_id = subflow_req->remote_id;
1590 new_ctx->token = subflow_req->token;
1591 new_ctx->thmac = subflow_req->thmac;
1595 static void tcp_release_cb_override(struct sock *ssk)
1597 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1599 if (mptcp_subflow_has_delegated_action(subflow))
1600 mptcp_subflow_process_delegated(ssk);
1602 tcp_release_cb(ssk);
1605 static struct tcp_ulp_ops subflow_ulp_ops __read_mostly = {
1607 .owner = THIS_MODULE,
1608 .init = subflow_ulp_init,
1609 .release = subflow_ulp_release,
1610 .clone = subflow_ulp_clone,
1613 static int subflow_ops_init(struct request_sock_ops *subflow_ops)
1615 subflow_ops->obj_size = sizeof(struct mptcp_subflow_request_sock);
1616 subflow_ops->slab_name = "request_sock_subflow";
1618 subflow_ops->slab = kmem_cache_create(subflow_ops->slab_name,
1619 subflow_ops->obj_size, 0,
1621 SLAB_TYPESAFE_BY_RCU,
1623 if (!subflow_ops->slab)
1626 subflow_ops->destructor = subflow_req_destructor;
1631 void __init mptcp_subflow_init(void)
1633 mptcp_subflow_request_sock_ops = tcp_request_sock_ops;
1634 if (subflow_ops_init(&mptcp_subflow_request_sock_ops) != 0)
1635 panic("MPTCP: failed to init subflow request sock ops\n");
1637 subflow_request_sock_ipv4_ops = tcp_request_sock_ipv4_ops;
1638 subflow_request_sock_ipv4_ops.route_req = subflow_v4_route_req;
1640 subflow_specific = ipv4_specific;
1641 subflow_specific.conn_request = subflow_v4_conn_request;
1642 subflow_specific.syn_recv_sock = subflow_syn_recv_sock;
1643 subflow_specific.sk_rx_dst_set = subflow_finish_connect;
1645 tcp_prot_override = tcp_prot;
1646 tcp_prot_override.release_cb = tcp_release_cb_override;
1648 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1649 subflow_request_sock_ipv6_ops = tcp_request_sock_ipv6_ops;
1650 subflow_request_sock_ipv6_ops.route_req = subflow_v6_route_req;
1652 subflow_v6_specific = ipv6_specific;
1653 subflow_v6_specific.conn_request = subflow_v6_conn_request;
1654 subflow_v6_specific.syn_recv_sock = subflow_syn_recv_sock;
1655 subflow_v6_specific.sk_rx_dst_set = subflow_finish_connect;
1657 subflow_v6m_specific = subflow_v6_specific;
1658 subflow_v6m_specific.queue_xmit = ipv4_specific.queue_xmit;
1659 subflow_v6m_specific.send_check = ipv4_specific.send_check;
1660 subflow_v6m_specific.net_header_len = ipv4_specific.net_header_len;
1661 subflow_v6m_specific.mtu_reduced = ipv4_specific.mtu_reduced;
1662 subflow_v6m_specific.net_frag_header_len = 0;
1664 tcpv6_prot_override = tcpv6_prot;
1665 tcpv6_prot_override.release_cb = tcp_release_cb_override;
1668 mptcp_diag_subflow_init(&subflow_ulp_ops);
1670 if (tcp_register_ulp(&subflow_ulp_ops) != 0)
1671 panic("MPTCP: failed to register subflows to ULP\n");