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 #include <trace/events/mptcp.h>
30 static void mptcp_subflow_ops_undo_override(struct sock *ssk);
32 static void SUBFLOW_REQ_INC_STATS(struct request_sock *req,
33 enum linux_mptcp_mib_field field)
35 MPTCP_INC_STATS(sock_net(req_to_sk(req)), field);
38 static void subflow_req_destructor(struct request_sock *req)
40 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
42 pr_debug("subflow_req=%p", subflow_req);
45 sock_put((struct sock *)subflow_req->msk);
47 mptcp_token_destroy_request(req);
48 tcp_request_sock_ops.destructor(req);
51 static void subflow_generate_hmac(u64 key1, u64 key2, u32 nonce1, u32 nonce2,
56 put_unaligned_be32(nonce1, &msg[0]);
57 put_unaligned_be32(nonce2, &msg[4]);
59 mptcp_crypto_hmac_sha(key1, key2, msg, 8, hmac);
62 static bool mptcp_can_accept_new_subflow(const struct mptcp_sock *msk)
64 return mptcp_is_fully_established((void *)msk) &&
65 READ_ONCE(msk->pm.accept_subflow);
68 /* validate received token and create truncated hmac and nonce for SYN-ACK */
69 static void subflow_req_create_thmac(struct mptcp_subflow_request_sock *subflow_req)
71 struct mptcp_sock *msk = subflow_req->msk;
72 u8 hmac[SHA256_DIGEST_SIZE];
74 get_random_bytes(&subflow_req->local_nonce, sizeof(u32));
76 subflow_generate_hmac(msk->local_key, msk->remote_key,
77 subflow_req->local_nonce,
78 subflow_req->remote_nonce, hmac);
80 subflow_req->thmac = get_unaligned_be64(hmac);
83 static struct mptcp_sock *subflow_token_join_request(struct request_sock *req)
85 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
86 struct mptcp_sock *msk;
89 msk = mptcp_token_get_sock(subflow_req->token);
91 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINNOTOKEN);
95 local_id = mptcp_pm_get_local_id(msk, (struct sock_common *)req);
97 sock_put((struct sock *)msk);
100 subflow_req->local_id = local_id;
105 static void subflow_init_req(struct request_sock *req, const struct sock *sk_listener)
107 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
109 subflow_req->mp_capable = 0;
110 subflow_req->mp_join = 0;
111 subflow_req->msk = NULL;
112 mptcp_token_init_request(req);
115 static bool subflow_use_different_sport(struct mptcp_sock *msk, const struct sock *sk)
117 return inet_sk(sk)->inet_sport != inet_sk((struct sock *)msk)->inet_sport;
120 static void subflow_add_reset_reason(struct sk_buff *skb, u8 reason)
122 struct mptcp_ext *mpext = skb_ext_add(skb, SKB_EXT_MPTCP);
125 memset(mpext, 0, sizeof(*mpext));
126 mpext->reset_reason = reason;
130 /* Init mptcp request socket.
132 * Returns an error code if a JOIN has failed and a TCP reset
135 static int subflow_check_req(struct request_sock *req,
136 const struct sock *sk_listener,
139 struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener);
140 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
141 struct mptcp_options_received mp_opt;
143 pr_debug("subflow_req=%p, listener=%p", subflow_req, listener);
145 #ifdef CONFIG_TCP_MD5SIG
146 /* no MPTCP if MD5SIG is enabled on this socket or we may run out of
149 if (rcu_access_pointer(tcp_sk(sk_listener)->md5sig_info))
153 mptcp_get_options(skb, &mp_opt);
155 if (mp_opt.mp_capable) {
156 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MPCAPABLEPASSIVE);
160 } else if (mp_opt.mp_join) {
161 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINSYNRX);
164 if (mp_opt.mp_capable && listener->request_mptcp) {
165 int err, retries = 4;
167 subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq;
170 get_random_bytes(&subflow_req->local_key, sizeof(subflow_req->local_key));
171 } while (subflow_req->local_key == 0);
173 if (unlikely(req->syncookie)) {
174 mptcp_crypto_key_sha(subflow_req->local_key,
177 if (mptcp_token_exists(subflow_req->token)) {
180 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_TOKENFALLBACKINIT);
182 subflow_req->mp_capable = 1;
187 err = mptcp_token_new_request(req);
189 subflow_req->mp_capable = 1;
190 else if (retries-- > 0)
193 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_TOKENFALLBACKINIT);
195 } else if (mp_opt.mp_join && listener->request_mptcp) {
196 subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq;
197 subflow_req->mp_join = 1;
198 subflow_req->backup = mp_opt.backup;
199 subflow_req->remote_id = mp_opt.join_id;
200 subflow_req->token = mp_opt.token;
201 subflow_req->remote_nonce = mp_opt.nonce;
202 subflow_req->msk = subflow_token_join_request(req);
204 /* Can't fall back to TCP in this case. */
205 if (!subflow_req->msk) {
206 subflow_add_reset_reason(skb, MPTCP_RST_EMPTCP);
210 if (subflow_use_different_sport(subflow_req->msk, sk_listener)) {
211 pr_debug("syn inet_sport=%d %d",
212 ntohs(inet_sk(sk_listener)->inet_sport),
213 ntohs(inet_sk((struct sock *)subflow_req->msk)->inet_sport));
214 if (!mptcp_pm_sport_in_anno_list(subflow_req->msk, sk_listener)) {
215 sock_put((struct sock *)subflow_req->msk);
216 mptcp_token_destroy_request(req);
217 tcp_request_sock_ops.destructor(req);
218 subflow_req->msk = NULL;
219 subflow_req->mp_join = 0;
220 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MISMATCHPORTSYNRX);
223 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINPORTSYNRX);
226 subflow_req_create_thmac(subflow_req);
228 if (unlikely(req->syncookie)) {
229 if (mptcp_can_accept_new_subflow(subflow_req->msk))
230 subflow_init_req_cookie_join_save(subflow_req, skb);
233 pr_debug("token=%u, remote_nonce=%u msk=%p", subflow_req->token,
234 subflow_req->remote_nonce, subflow_req->msk);
240 int mptcp_subflow_init_cookie_req(struct request_sock *req,
241 const struct sock *sk_listener,
244 struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener);
245 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
246 struct mptcp_options_received mp_opt;
249 subflow_init_req(req, sk_listener);
250 mptcp_get_options(skb, &mp_opt);
252 if (mp_opt.mp_capable && mp_opt.mp_join)
255 if (mp_opt.mp_capable && listener->request_mptcp) {
256 if (mp_opt.sndr_key == 0)
259 subflow_req->local_key = mp_opt.rcvr_key;
260 err = mptcp_token_new_request(req);
264 subflow_req->mp_capable = 1;
265 subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1;
266 } else if (mp_opt.mp_join && listener->request_mptcp) {
267 if (!mptcp_token_join_cookie_init_state(subflow_req, skb))
270 if (mptcp_can_accept_new_subflow(subflow_req->msk))
271 subflow_req->mp_join = 1;
273 subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1;
278 EXPORT_SYMBOL_GPL(mptcp_subflow_init_cookie_req);
280 static struct dst_entry *subflow_v4_route_req(const struct sock *sk,
283 struct request_sock *req)
285 struct dst_entry *dst;
288 tcp_rsk(req)->is_mptcp = 1;
289 subflow_init_req(req, sk);
291 dst = tcp_request_sock_ipv4_ops.route_req(sk, skb, fl, req);
295 err = subflow_check_req(req, sk, skb);
301 tcp_request_sock_ops.send_reset(sk, skb);
305 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
306 static struct dst_entry *subflow_v6_route_req(const struct sock *sk,
309 struct request_sock *req)
311 struct dst_entry *dst;
314 tcp_rsk(req)->is_mptcp = 1;
315 subflow_init_req(req, sk);
317 dst = tcp_request_sock_ipv6_ops.route_req(sk, skb, fl, req);
321 err = subflow_check_req(req, sk, skb);
327 tcp6_request_sock_ops.send_reset(sk, skb);
332 /* validate received truncated hmac and create hmac for third ACK */
333 static bool subflow_thmac_valid(struct mptcp_subflow_context *subflow)
335 u8 hmac[SHA256_DIGEST_SIZE];
338 subflow_generate_hmac(subflow->remote_key, subflow->local_key,
339 subflow->remote_nonce, subflow->local_nonce,
342 thmac = get_unaligned_be64(hmac);
343 pr_debug("subflow=%p, token=%u, thmac=%llu, subflow->thmac=%llu\n",
344 subflow, subflow->token,
345 (unsigned long long)thmac,
346 (unsigned long long)subflow->thmac);
348 return thmac == subflow->thmac;
351 void mptcp_subflow_reset(struct sock *ssk)
353 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
354 struct sock *sk = subflow->conn;
356 /* must hold: tcp_done() could drop last reference on parent */
359 tcp_set_state(ssk, TCP_CLOSE);
360 tcp_send_active_reset(ssk, GFP_ATOMIC);
362 if (!test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &mptcp_sk(sk)->flags) &&
363 schedule_work(&mptcp_sk(sk)->work))
364 return; /* worker will put sk for us */
369 static bool subflow_use_different_dport(struct mptcp_sock *msk, const struct sock *sk)
371 return inet_sk(sk)->inet_dport != inet_sk((struct sock *)msk)->inet_dport;
374 static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
376 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
377 struct mptcp_options_received mp_opt;
378 struct sock *parent = subflow->conn;
380 subflow->icsk_af_ops->sk_rx_dst_set(sk, skb);
382 if (inet_sk_state_load(parent) == TCP_SYN_SENT) {
383 inet_sk_state_store(parent, TCP_ESTABLISHED);
384 parent->sk_state_change(parent);
387 /* be sure no special action on any packet other than syn-ack */
388 if (subflow->conn_finished)
391 mptcp_propagate_sndbuf(parent, sk);
392 subflow->rel_write_seq = 1;
393 subflow->conn_finished = 1;
394 subflow->ssn_offset = TCP_SKB_CB(skb)->seq;
395 pr_debug("subflow=%p synack seq=%x", subflow, subflow->ssn_offset);
397 mptcp_get_options(skb, &mp_opt);
398 if (subflow->request_mptcp) {
399 if (!mp_opt.mp_capable) {
400 MPTCP_INC_STATS(sock_net(sk),
401 MPTCP_MIB_MPCAPABLEACTIVEFALLBACK);
402 mptcp_do_fallback(sk);
403 pr_fallback(mptcp_sk(subflow->conn));
407 subflow->mp_capable = 1;
408 subflow->can_ack = 1;
409 subflow->remote_key = mp_opt.sndr_key;
410 pr_debug("subflow=%p, remote_key=%llu", subflow,
411 subflow->remote_key);
412 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVEACK);
413 mptcp_finish_connect(sk);
414 } else if (subflow->request_join) {
415 u8 hmac[SHA256_DIGEST_SIZE];
417 if (!mp_opt.mp_join) {
418 subflow->reset_reason = MPTCP_RST_EMPTCP;
422 subflow->thmac = mp_opt.thmac;
423 subflow->remote_nonce = mp_opt.nonce;
424 pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u", subflow,
425 subflow->thmac, subflow->remote_nonce);
427 if (!subflow_thmac_valid(subflow)) {
428 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINACKMAC);
429 subflow->reset_reason = MPTCP_RST_EMPTCP;
433 subflow_generate_hmac(subflow->local_key, subflow->remote_key,
434 subflow->local_nonce,
435 subflow->remote_nonce,
437 memcpy(subflow->hmac, hmac, MPTCPOPT_HMAC_LEN);
439 if (!mptcp_finish_join(sk))
442 subflow->mp_join = 1;
443 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNACKRX);
445 if (subflow_use_different_dport(mptcp_sk(parent), sk)) {
446 pr_debug("synack inet_dport=%d %d",
447 ntohs(inet_sk(sk)->inet_dport),
448 ntohs(inet_sk(parent)->inet_dport));
449 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINPORTSYNACKRX);
451 } else if (mptcp_check_fallback(sk)) {
453 mptcp_rcv_space_init(mptcp_sk(parent), sk);
458 subflow->reset_transient = 0;
459 mptcp_subflow_reset(sk);
462 struct request_sock_ops mptcp_subflow_request_sock_ops;
463 EXPORT_SYMBOL_GPL(mptcp_subflow_request_sock_ops);
464 static struct tcp_request_sock_ops subflow_request_sock_ipv4_ops;
466 static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb)
468 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
470 pr_debug("subflow=%p", subflow);
472 /* Never answer to SYNs sent to broadcast or multicast */
473 if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
476 return tcp_conn_request(&mptcp_subflow_request_sock_ops,
477 &subflow_request_sock_ipv4_ops,
484 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
485 static struct tcp_request_sock_ops subflow_request_sock_ipv6_ops;
486 static struct inet_connection_sock_af_ops subflow_v6_specific;
487 static struct inet_connection_sock_af_ops subflow_v6m_specific;
488 static struct proto tcpv6_prot_override;
490 static int subflow_v6_conn_request(struct sock *sk, struct sk_buff *skb)
492 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
494 pr_debug("subflow=%p", subflow);
496 if (skb->protocol == htons(ETH_P_IP))
497 return subflow_v4_conn_request(sk, skb);
499 if (!ipv6_unicast_destination(skb))
502 if (ipv6_addr_v4mapped(&ipv6_hdr(skb)->saddr)) {
503 __IP6_INC_STATS(sock_net(sk), NULL, IPSTATS_MIB_INHDRERRORS);
507 return tcp_conn_request(&mptcp_subflow_request_sock_ops,
508 &subflow_request_sock_ipv6_ops, sk, skb);
512 return 0; /* don't send reset */
516 /* validate hmac received in third ACK */
517 static bool subflow_hmac_valid(const struct request_sock *req,
518 const struct mptcp_options_received *mp_opt)
520 const struct mptcp_subflow_request_sock *subflow_req;
521 u8 hmac[SHA256_DIGEST_SIZE];
522 struct mptcp_sock *msk;
524 subflow_req = mptcp_subflow_rsk(req);
525 msk = subflow_req->msk;
529 subflow_generate_hmac(msk->remote_key, msk->local_key,
530 subflow_req->remote_nonce,
531 subflow_req->local_nonce, hmac);
533 return !crypto_memneq(hmac, mp_opt->hmac, MPTCPOPT_HMAC_LEN);
536 static void mptcp_sock_destruct(struct sock *sk)
538 /* if new mptcp socket isn't accepted, it is free'd
539 * from the tcp listener sockets request queue, linked
540 * from req->sk. The tcp socket is released.
541 * This calls the ULP release function which will
542 * also remove the mptcp socket, via
543 * sock_put(ctx->conn).
545 * Problem is that the mptcp socket will be in
546 * ESTABLISHED state and will not have the SOCK_DEAD flag.
547 * Both result in warnings from inet_sock_destruct.
550 if (sk->sk_state == TCP_ESTABLISHED) {
551 sk->sk_state = TCP_CLOSE;
552 WARN_ON_ONCE(sk->sk_socket);
556 mptcp_destroy_common(mptcp_sk(sk));
557 inet_sock_destruct(sk);
560 static void mptcp_force_close(struct sock *sk)
562 inet_sk_state_store(sk, TCP_CLOSE);
563 sk_common_release(sk);
566 static void subflow_ulp_fallback(struct sock *sk,
567 struct mptcp_subflow_context *old_ctx)
569 struct inet_connection_sock *icsk = inet_csk(sk);
571 mptcp_subflow_tcp_fallback(sk, old_ctx);
572 icsk->icsk_ulp_ops = NULL;
573 rcu_assign_pointer(icsk->icsk_ulp_data, NULL);
574 tcp_sk(sk)->is_mptcp = 0;
576 mptcp_subflow_ops_undo_override(sk);
579 static void subflow_drop_ctx(struct sock *ssk)
581 struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(ssk);
586 subflow_ulp_fallback(ssk, ctx);
593 void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,
594 struct mptcp_options_received *mp_opt)
596 struct mptcp_sock *msk = mptcp_sk(subflow->conn);
598 subflow->remote_key = mp_opt->sndr_key;
599 subflow->fully_established = 1;
600 subflow->can_ack = 1;
601 WRITE_ONCE(msk->fully_established, true);
604 static struct sock *subflow_syn_recv_sock(const struct sock *sk,
606 struct request_sock *req,
607 struct dst_entry *dst,
608 struct request_sock *req_unhash,
611 struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk);
612 struct mptcp_subflow_request_sock *subflow_req;
613 struct mptcp_options_received mp_opt;
614 bool fallback, fallback_is_fatal;
615 struct sock *new_msk = NULL;
618 pr_debug("listener=%p, req=%p, conn=%p", listener, req, listener->conn);
620 /* After child creation we must look for 'mp_capable' even when options
623 mp_opt.mp_capable = 0;
625 /* hopefully temporary handling for MP_JOIN+syncookie */
626 subflow_req = mptcp_subflow_rsk(req);
627 fallback_is_fatal = tcp_rsk(req)->is_mptcp && subflow_req->mp_join;
628 fallback = !tcp_rsk(req)->is_mptcp;
632 /* if the sk is MP_CAPABLE, we try to fetch the client key */
633 if (subflow_req->mp_capable) {
634 if (TCP_SKB_CB(skb)->seq != subflow_req->ssn_offset + 1) {
635 /* here we can receive and accept an in-window,
636 * out-of-order pkt, which will not carry the MP_CAPABLE
637 * opt even on mptcp enabled paths
642 mptcp_get_options(skb, &mp_opt);
643 if (!mp_opt.mp_capable) {
649 new_msk = mptcp_sk_clone(listener->conn, &mp_opt, req);
652 } else if (subflow_req->mp_join) {
653 mptcp_get_options(skb, &mp_opt);
654 if (!mp_opt.mp_join || !subflow_hmac_valid(req, &mp_opt) ||
655 !mptcp_can_accept_new_subflow(subflow_req->msk)) {
656 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC);
662 child = listener->icsk_af_ops->syn_recv_sock(sk, skb, req, dst,
663 req_unhash, own_req);
665 if (child && *own_req) {
666 struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(child);
668 tcp_rsk(req)->drop_req = false;
670 /* we need to fallback on ctx allocation failure and on pre-reqs
671 * checking above. In the latter scenario we additionally need
672 * to reset the context to non MPTCP status.
674 if (!ctx || fallback) {
675 if (fallback_is_fatal) {
676 subflow_add_reset_reason(skb, MPTCP_RST_EMPTCP);
680 subflow_drop_ctx(child);
684 /* ssk inherits options of listener sk */
685 ctx->setsockopt_seq = listener->setsockopt_seq;
687 if (ctx->mp_capable) {
688 /* this can't race with mptcp_close(), as the msk is
689 * not yet exposted to user-space
691 inet_sk_state_store((void *)new_msk, TCP_ESTABLISHED);
693 /* record the newly created socket as the first msk
694 * subflow, but don't link it yet into conn_list
696 WRITE_ONCE(mptcp_sk(new_msk)->first, child);
698 /* new mpc subflow takes ownership of the newly
699 * created mptcp socket
701 new_msk->sk_destruct = mptcp_sock_destruct;
702 mptcp_sk(new_msk)->setsockopt_seq = ctx->setsockopt_seq;
703 mptcp_pm_new_connection(mptcp_sk(new_msk), child, 1);
704 mptcp_token_accept(subflow_req, mptcp_sk(new_msk));
708 /* with OoO packets we can reach here without ingress
711 if (mp_opt.mp_capable)
712 mptcp_subflow_fully_established(ctx, &mp_opt);
713 } else if (ctx->mp_join) {
714 struct mptcp_sock *owner;
716 owner = subflow_req->msk;
718 subflow_add_reset_reason(skb, MPTCP_RST_EPROHIBIT);
722 /* move the msk reference ownership to the subflow */
723 subflow_req->msk = NULL;
724 ctx->conn = (struct sock *)owner;
726 if (subflow_use_different_sport(owner, sk)) {
727 pr_debug("ack inet_sport=%d %d",
728 ntohs(inet_sk(sk)->inet_sport),
729 ntohs(inet_sk((struct sock *)owner)->inet_sport));
730 if (!mptcp_pm_sport_in_anno_list(owner, sk)) {
731 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MISMATCHPORTACKRX);
734 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINPORTACKRX);
737 if (!mptcp_finish_join(child))
740 SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKRX);
741 tcp_rsk(req)->drop_req = true;
746 /* dispose of the left over mptcp master, if any */
747 if (unlikely(new_msk))
748 mptcp_force_close(new_msk);
750 /* check for expected invariant - should never trigger, just help
751 * catching eariler subtle bugs
753 WARN_ON_ONCE(child && *own_req && tcp_sk(child)->is_mptcp &&
754 (!mptcp_subflow_ctx(child) ||
755 !mptcp_subflow_ctx(child)->conn));
759 subflow_drop_ctx(child);
760 tcp_rsk(req)->drop_req = true;
761 inet_csk_prepare_for_destroy_sock(child);
763 req->rsk_ops->send_reset(sk, skb);
765 /* The last child reference will be released by the caller */
769 static struct inet_connection_sock_af_ops subflow_specific;
770 static struct proto tcp_prot_override;
772 enum mapping_status {
780 static u64 expand_seq(u64 old_seq, u16 old_data_len, u64 seq)
782 if ((u32)seq == (u32)old_seq)
785 /* Assume map covers data not mapped yet. */
786 return seq | ((old_seq + old_data_len + 1) & GENMASK_ULL(63, 32));
789 static void warn_bad_map(struct mptcp_subflow_context *subflow, u32 ssn)
791 WARN_ONCE(1, "Bad mapping: ssn=%d map_seq=%d map_data_len=%d",
792 ssn, subflow->map_subflow_seq, subflow->map_data_len);
795 static bool skb_is_fully_mapped(struct sock *ssk, struct sk_buff *skb)
797 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
798 unsigned int skb_consumed;
800 skb_consumed = tcp_sk(ssk)->copied_seq - TCP_SKB_CB(skb)->seq;
801 if (WARN_ON_ONCE(skb_consumed >= skb->len))
804 return skb->len - skb_consumed <= subflow->map_data_len -
805 mptcp_subflow_get_map_offset(subflow);
808 static bool validate_mapping(struct sock *ssk, struct sk_buff *skb)
810 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
811 u32 ssn = tcp_sk(ssk)->copied_seq - subflow->ssn_offset;
813 if (unlikely(before(ssn, subflow->map_subflow_seq))) {
814 /* Mapping covers data later in the subflow stream,
815 * currently unsupported.
817 warn_bad_map(subflow, ssn);
820 if (unlikely(!before(ssn, subflow->map_subflow_seq +
821 subflow->map_data_len))) {
822 /* Mapping does covers past subflow data, invalid */
823 warn_bad_map(subflow, ssn + skb->len);
829 static enum mapping_status get_mapping_status(struct sock *ssk,
830 struct mptcp_sock *msk)
832 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
833 struct mptcp_ext *mpext;
838 skb = skb_peek(&ssk->sk_receive_queue);
840 return MAPPING_EMPTY;
842 if (mptcp_check_fallback(ssk))
843 return MAPPING_DUMMY;
845 mpext = mptcp_get_ext(skb);
846 if (!mpext || !mpext->use_map) {
847 if (!subflow->map_valid && !skb->len) {
848 /* the TCP stack deliver 0 len FIN pkt to the receive
849 * queue, that is the only 0len pkts ever expected here,
850 * and we can admit no mapping only for 0 len pkts
852 if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN))
853 WARN_ONCE(1, "0len seq %d:%d flags %x",
854 TCP_SKB_CB(skb)->seq,
855 TCP_SKB_CB(skb)->end_seq,
856 TCP_SKB_CB(skb)->tcp_flags);
857 sk_eat_skb(ssk, skb);
858 return MAPPING_EMPTY;
861 if (!subflow->map_valid)
862 return MAPPING_INVALID;
867 trace_get_mapping_status(mpext);
869 data_len = mpext->data_len;
871 pr_err("Infinite mapping not handled");
872 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPRX);
873 return MAPPING_INVALID;
876 if (mpext->data_fin == 1) {
878 bool updated = mptcp_update_rcv_data_fin(msk, mpext->data_seq,
880 pr_debug("DATA_FIN with no payload seq=%llu", mpext->data_seq);
881 if (subflow->map_valid) {
882 /* A DATA_FIN might arrive in a DSS
883 * option before the previous mapping
884 * has been fully consumed. Continue
885 * handling the existing mapping.
887 skb_ext_del(skb, SKB_EXT_MPTCP);
890 if (updated && schedule_work(&msk->work))
891 sock_hold((struct sock *)msk);
893 return MAPPING_DATA_FIN;
896 u64 data_fin_seq = mpext->data_seq + data_len - 1;
898 /* If mpext->data_seq is a 32-bit value, data_fin_seq
899 * must also be limited to 32 bits.
902 data_fin_seq &= GENMASK_ULL(31, 0);
904 mptcp_update_rcv_data_fin(msk, data_fin_seq, mpext->dsn64);
905 pr_debug("DATA_FIN with mapping seq=%llu dsn64=%d",
906 data_fin_seq, mpext->dsn64);
909 /* Adjust for DATA_FIN using 1 byte of sequence space */
914 map_seq = expand_seq(subflow->map_seq, subflow->map_data_len,
916 pr_debug("expanded seq=%llu", subflow->map_seq);
918 map_seq = mpext->data_seq;
920 WRITE_ONCE(mptcp_sk(subflow->conn)->use_64bit_ack, !!mpext->dsn64);
922 if (subflow->map_valid) {
923 /* Allow replacing only with an identical map */
924 if (subflow->map_seq == map_seq &&
925 subflow->map_subflow_seq == mpext->subflow_seq &&
926 subflow->map_data_len == data_len) {
927 skb_ext_del(skb, SKB_EXT_MPTCP);
931 /* If this skb data are fully covered by the current mapping,
932 * the new map would need caching, which is not supported
934 if (skb_is_fully_mapped(ssk, skb)) {
935 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DSSNOMATCH);
936 return MAPPING_INVALID;
939 /* will validate the next map after consuming the current one */
943 subflow->map_seq = map_seq;
944 subflow->map_subflow_seq = mpext->subflow_seq;
945 subflow->map_data_len = data_len;
946 subflow->map_valid = 1;
947 subflow->mpc_map = mpext->mpc_map;
948 pr_debug("new map seq=%llu subflow_seq=%u data_len=%u",
949 subflow->map_seq, subflow->map_subflow_seq,
950 subflow->map_data_len);
953 /* we revalidate valid mapping on new skb, because we must ensure
954 * the current skb is completely covered by the available mapping
956 if (!validate_mapping(ssk, skb))
957 return MAPPING_INVALID;
959 skb_ext_del(skb, SKB_EXT_MPTCP);
963 static void mptcp_subflow_discard_data(struct sock *ssk, struct sk_buff *skb,
966 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
967 bool fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
970 incr = limit >= skb->len ? skb->len + fin : limit;
972 pr_debug("discarding=%d len=%d seq=%d", incr, skb->len,
973 subflow->map_subflow_seq);
974 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DUPDATA);
975 tcp_sk(ssk)->copied_seq += incr;
976 if (!before(tcp_sk(ssk)->copied_seq, TCP_SKB_CB(skb)->end_seq))
977 sk_eat_skb(ssk, skb);
978 if (mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len)
979 subflow->map_valid = 0;
982 /* sched mptcp worker to remove the subflow if no more data is pending */
983 static void subflow_sched_work_if_closed(struct mptcp_sock *msk, struct sock *ssk)
985 struct sock *sk = (struct sock *)msk;
987 if (likely(ssk->sk_state != TCP_CLOSE))
990 if (skb_queue_empty(&ssk->sk_receive_queue) &&
991 !test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags)) {
993 if (!schedule_work(&msk->work))
998 static bool subflow_check_data_avail(struct sock *ssk)
1000 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1001 enum mapping_status status;
1002 struct mptcp_sock *msk;
1003 struct sk_buff *skb;
1005 if (!skb_peek(&ssk->sk_receive_queue))
1006 subflow->data_avail = 0;
1007 if (subflow->data_avail)
1010 msk = mptcp_sk(subflow->conn);
1015 status = get_mapping_status(ssk, msk);
1016 trace_subflow_check_data_avail(status, skb_peek(&ssk->sk_receive_queue));
1017 if (status == MAPPING_INVALID) {
1018 ssk->sk_err = EBADMSG;
1021 if (status == MAPPING_DUMMY) {
1022 __mptcp_do_fallback(msk);
1023 skb = skb_peek(&ssk->sk_receive_queue);
1024 subflow->map_valid = 1;
1025 subflow->map_seq = READ_ONCE(msk->ack_seq);
1026 subflow->map_data_len = skb->len;
1027 subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq -
1028 subflow->ssn_offset;
1029 subflow->data_avail = MPTCP_SUBFLOW_DATA_AVAIL;
1033 if (status != MAPPING_OK)
1036 skb = skb_peek(&ssk->sk_receive_queue);
1037 if (WARN_ON_ONCE(!skb))
1040 /* if msk lacks the remote key, this subflow must provide an
1041 * MP_CAPABLE-based mapping
1043 if (unlikely(!READ_ONCE(msk->can_ack))) {
1044 if (!subflow->mpc_map) {
1045 ssk->sk_err = EBADMSG;
1048 WRITE_ONCE(msk->remote_key, subflow->remote_key);
1049 WRITE_ONCE(msk->ack_seq, subflow->map_seq);
1050 WRITE_ONCE(msk->can_ack, true);
1053 old_ack = READ_ONCE(msk->ack_seq);
1054 ack_seq = mptcp_subflow_get_mapped_dsn(subflow);
1055 pr_debug("msk ack_seq=%llx subflow ack_seq=%llx", old_ack,
1057 if (ack_seq == old_ack) {
1058 subflow->data_avail = MPTCP_SUBFLOW_DATA_AVAIL;
1060 } else if (after64(ack_seq, old_ack)) {
1061 subflow->data_avail = MPTCP_SUBFLOW_OOO_DATA;
1065 /* only accept in-sequence mapping. Old values are spurious
1068 mptcp_subflow_discard_data(ssk, skb, old_ack - ack_seq);
1073 subflow_sched_work_if_closed(msk, ssk);
1076 /* fatal protocol error, close the socket */
1077 /* This barrier is coupled with smp_rmb() in tcp_poll() */
1079 ssk->sk_error_report(ssk);
1080 tcp_set_state(ssk, TCP_CLOSE);
1081 subflow->reset_transient = 0;
1082 subflow->reset_reason = MPTCP_RST_EMPTCP;
1083 tcp_send_active_reset(ssk, GFP_ATOMIC);
1084 subflow->data_avail = 0;
1088 bool mptcp_subflow_data_available(struct sock *sk)
1090 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1092 /* check if current mapping is still valid */
1093 if (subflow->map_valid &&
1094 mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len) {
1095 subflow->map_valid = 0;
1096 subflow->data_avail = 0;
1098 pr_debug("Done with mapping: seq=%u data_len=%u",
1099 subflow->map_subflow_seq,
1100 subflow->map_data_len);
1103 return subflow_check_data_avail(sk);
1106 /* If ssk has an mptcp parent socket, use the mptcp rcvbuf occupancy,
1109 * In mptcp, rwin is about the mptcp-level connection data.
1111 * Data that is still on the ssk rx queue can thus be ignored,
1112 * as far as mptcp peer is concerned that data is still inflight.
1113 * DSS ACK is updated when skb is moved to the mptcp rx queue.
1115 void mptcp_space(const struct sock *ssk, int *space, int *full_space)
1117 const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1118 const struct sock *sk = subflow->conn;
1120 *space = __mptcp_space(sk);
1121 *full_space = tcp_full_space(sk);
1124 static void subflow_data_ready(struct sock *sk)
1126 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1127 u16 state = 1 << inet_sk_state_load(sk);
1128 struct sock *parent = subflow->conn;
1129 struct mptcp_sock *msk;
1131 msk = mptcp_sk(parent);
1132 if (state & TCPF_LISTEN) {
1133 /* MPJ subflow are removed from accept queue before reaching here,
1134 * avoid stray wakeups
1136 if (reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue))
1139 set_bit(MPTCP_DATA_READY, &msk->flags);
1140 parent->sk_data_ready(parent);
1144 WARN_ON_ONCE(!__mptcp_check_fallback(msk) && !subflow->mp_capable &&
1145 !subflow->mp_join && !(state & TCPF_CLOSE));
1147 if (mptcp_subflow_data_available(sk))
1148 mptcp_data_ready(parent, sk);
1151 static void subflow_write_space(struct sock *ssk)
1153 struct sock *sk = mptcp_subflow_ctx(ssk)->conn;
1155 mptcp_propagate_sndbuf(sk, ssk);
1156 mptcp_write_space(sk);
1159 void __mptcp_error_report(struct sock *sk)
1161 struct mptcp_subflow_context *subflow;
1162 struct mptcp_sock *msk = mptcp_sk(sk);
1164 mptcp_for_each_subflow(msk, subflow) {
1165 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
1166 int err = sock_error(ssk);
1171 /* only propagate errors on fallen-back sockets or
1174 if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(msk))
1177 inet_sk_state_store(sk, inet_sk_state_load(ssk));
1180 /* This barrier is coupled with smp_rmb() in mptcp_poll() */
1182 sk->sk_error_report(sk);
1187 static void subflow_error_report(struct sock *ssk)
1189 struct sock *sk = mptcp_subflow_ctx(ssk)->conn;
1191 mptcp_data_lock(sk);
1192 if (!sock_owned_by_user(sk))
1193 __mptcp_error_report(sk);
1195 set_bit(MPTCP_ERROR_REPORT, &mptcp_sk(sk)->flags);
1196 mptcp_data_unlock(sk);
1199 static struct inet_connection_sock_af_ops *
1200 subflow_default_af_ops(struct sock *sk)
1202 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1203 if (sk->sk_family == AF_INET6)
1204 return &subflow_v6_specific;
1206 return &subflow_specific;
1209 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1210 void mptcpv6_handle_mapped(struct sock *sk, bool mapped)
1212 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1213 struct inet_connection_sock *icsk = inet_csk(sk);
1214 struct inet_connection_sock_af_ops *target;
1216 target = mapped ? &subflow_v6m_specific : subflow_default_af_ops(sk);
1218 pr_debug("subflow=%p family=%d ops=%p target=%p mapped=%d",
1219 subflow, sk->sk_family, icsk->icsk_af_ops, target, mapped);
1221 if (likely(icsk->icsk_af_ops == target))
1224 subflow->icsk_af_ops = icsk->icsk_af_ops;
1225 icsk->icsk_af_ops = target;
1229 void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
1230 struct sockaddr_storage *addr,
1231 unsigned short family)
1233 memset(addr, 0, sizeof(*addr));
1234 addr->ss_family = family;
1235 if (addr->ss_family == AF_INET) {
1236 struct sockaddr_in *in_addr = (struct sockaddr_in *)addr;
1238 if (info->family == AF_INET)
1239 in_addr->sin_addr = info->addr;
1240 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1241 else if (ipv6_addr_v4mapped(&info->addr6))
1242 in_addr->sin_addr.s_addr = info->addr6.s6_addr32[3];
1244 in_addr->sin_port = info->port;
1246 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1247 else if (addr->ss_family == AF_INET6) {
1248 struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)addr;
1250 if (info->family == AF_INET)
1251 ipv6_addr_set_v4mapped(info->addr.s_addr,
1252 &in6_addr->sin6_addr);
1254 in6_addr->sin6_addr = info->addr6;
1255 in6_addr->sin6_port = info->port;
1260 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
1261 const struct mptcp_addr_info *remote,
1262 u8 flags, int ifindex)
1264 struct mptcp_sock *msk = mptcp_sk(sk);
1265 struct mptcp_subflow_context *subflow;
1266 struct sockaddr_storage addr;
1267 int remote_id = remote->id;
1268 int local_id = loc->id;
1275 if (!mptcp_is_fully_established(sk))
1278 err = mptcp_subflow_create_socket(sk, &sf);
1283 subflow = mptcp_subflow_ctx(ssk);
1285 get_random_bytes(&subflow->local_nonce, sizeof(u32));
1286 } while (!subflow->local_nonce);
1289 err = mptcp_pm_get_local_id(msk, (struct sock_common *)ssk);
1296 subflow->remote_key = msk->remote_key;
1297 subflow->local_key = msk->local_key;
1298 subflow->token = msk->token;
1299 mptcp_info2sockaddr(loc, &addr, ssk->sk_family);
1301 addrlen = sizeof(struct sockaddr_in);
1302 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1303 if (addr.ss_family == AF_INET6)
1304 addrlen = sizeof(struct sockaddr_in6);
1306 ssk->sk_bound_dev_if = ifindex;
1307 err = kernel_bind(sf, (struct sockaddr *)&addr, addrlen);
1311 mptcp_crypto_key_sha(subflow->remote_key, &remote_token, NULL);
1312 pr_debug("msk=%p remote_token=%u local_id=%d remote_id=%d", msk,
1313 remote_token, local_id, remote_id);
1314 subflow->remote_token = remote_token;
1315 subflow->local_id = local_id;
1316 subflow->remote_id = remote_id;
1317 subflow->request_join = 1;
1318 subflow->request_bkup = !!(flags & MPTCP_PM_ADDR_FLAG_BACKUP);
1319 mptcp_info2sockaddr(remote, &addr, ssk->sk_family);
1321 mptcp_add_pending_subflow(msk, subflow);
1322 mptcp_sockopt_sync(msk, ssk);
1323 err = kernel_connect(sf, (struct sockaddr *)&addr, addrlen, O_NONBLOCK);
1324 if (err && err != -EINPROGRESS)
1327 /* discard the subflow socket */
1328 mptcp_sock_graft(ssk, sk->sk_socket);
1329 iput(SOCK_INODE(sf));
1333 spin_lock_bh(&msk->join_list_lock);
1334 list_del(&subflow->node);
1335 spin_unlock_bh(&msk->join_list_lock);
1336 sock_put(mptcp_subflow_tcp_sock(subflow));
1339 subflow->disposable = 1;
1344 static void mptcp_attach_cgroup(struct sock *parent, struct sock *child)
1346 #ifdef CONFIG_SOCK_CGROUP_DATA
1347 struct sock_cgroup_data *parent_skcd = &parent->sk_cgrp_data,
1348 *child_skcd = &child->sk_cgrp_data;
1350 /* only the additional subflows created by kworkers have to be modified */
1351 if (cgroup_id(sock_cgroup_ptr(parent_skcd)) !=
1352 cgroup_id(sock_cgroup_ptr(child_skcd))) {
1354 struct mem_cgroup *memcg = parent->sk_memcg;
1356 mem_cgroup_sk_free(child);
1357 if (memcg && css_tryget(&memcg->css))
1358 child->sk_memcg = memcg;
1359 #endif /* CONFIG_MEMCG */
1361 cgroup_sk_free(child_skcd);
1362 *child_skcd = *parent_skcd;
1363 cgroup_sk_clone(child_skcd);
1365 #endif /* CONFIG_SOCK_CGROUP_DATA */
1368 static void mptcp_subflow_ops_override(struct sock *ssk)
1370 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1371 if (ssk->sk_prot == &tcpv6_prot)
1372 ssk->sk_prot = &tcpv6_prot_override;
1375 ssk->sk_prot = &tcp_prot_override;
1378 static void mptcp_subflow_ops_undo_override(struct sock *ssk)
1380 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1381 if (ssk->sk_prot == &tcpv6_prot_override)
1382 ssk->sk_prot = &tcpv6_prot;
1385 ssk->sk_prot = &tcp_prot;
1387 int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock)
1389 struct mptcp_subflow_context *subflow;
1390 struct net *net = sock_net(sk);
1394 /* un-accepted server sockets can reach here - on bad configuration
1395 * bail early to avoid greater trouble later
1397 if (unlikely(!sk->sk_socket))
1400 err = sock_create_kern(net, sk->sk_family, SOCK_STREAM, IPPROTO_TCP,
1407 /* the newly created socket has to be in the same cgroup as its parent */
1408 mptcp_attach_cgroup(sk, sf->sk);
1410 /* kernel sockets do not by default acquire net ref, but TCP timer
1413 sf->sk->sk_net_refcnt = 1;
1415 #ifdef CONFIG_PROC_FS
1416 this_cpu_add(*net->core.sock_inuse, 1);
1418 err = tcp_set_ulp(sf->sk, "mptcp");
1419 release_sock(sf->sk);
1426 /* the newly created socket really belongs to the owning MPTCP master
1427 * socket, even if for additional subflows the allocation is performed
1428 * by a kernel workqueue. Adjust inode references, so that the
1429 * procfs/diag interaces really show this one belonging to the correct
1432 SOCK_INODE(sf)->i_ino = SOCK_INODE(sk->sk_socket)->i_ino;
1433 SOCK_INODE(sf)->i_uid = SOCK_INODE(sk->sk_socket)->i_uid;
1434 SOCK_INODE(sf)->i_gid = SOCK_INODE(sk->sk_socket)->i_gid;
1436 subflow = mptcp_subflow_ctx(sf->sk);
1437 pr_debug("subflow=%p", subflow);
1442 mptcp_subflow_ops_override(sf->sk);
1447 static struct mptcp_subflow_context *subflow_create_ctx(struct sock *sk,
1450 struct inet_connection_sock *icsk = inet_csk(sk);
1451 struct mptcp_subflow_context *ctx;
1453 ctx = kzalloc(sizeof(*ctx), priority);
1457 rcu_assign_pointer(icsk->icsk_ulp_data, ctx);
1458 INIT_LIST_HEAD(&ctx->node);
1459 INIT_LIST_HEAD(&ctx->delegated_node);
1461 pr_debug("subflow=%p", ctx);
1468 static void __subflow_state_change(struct sock *sk)
1470 struct socket_wq *wq;
1473 wq = rcu_dereference(sk->sk_wq);
1474 if (skwq_has_sleeper(wq))
1475 wake_up_interruptible_all(&wq->wait);
1479 static bool subflow_is_done(const struct sock *sk)
1481 return sk->sk_shutdown & RCV_SHUTDOWN || sk->sk_state == TCP_CLOSE;
1484 static void subflow_state_change(struct sock *sk)
1486 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1487 struct sock *parent = subflow->conn;
1489 __subflow_state_change(sk);
1491 if (subflow_simultaneous_connect(sk)) {
1492 mptcp_propagate_sndbuf(parent, sk);
1493 mptcp_do_fallback(sk);
1494 mptcp_rcv_space_init(mptcp_sk(parent), sk);
1495 pr_fallback(mptcp_sk(parent));
1496 subflow->conn_finished = 1;
1497 if (inet_sk_state_load(parent) == TCP_SYN_SENT) {
1498 inet_sk_state_store(parent, TCP_ESTABLISHED);
1499 parent->sk_state_change(parent);
1503 /* as recvmsg() does not acquire the subflow socket for ssk selection
1504 * a fin packet carrying a DSS can be unnoticed if we don't trigger
1505 * the data available machinery here.
1507 if (mptcp_subflow_data_available(sk))
1508 mptcp_data_ready(parent, sk);
1510 subflow_sched_work_if_closed(mptcp_sk(parent), sk);
1512 if (__mptcp_check_fallback(mptcp_sk(parent)) &&
1513 !subflow->rx_eof && subflow_is_done(sk)) {
1514 subflow->rx_eof = 1;
1515 mptcp_subflow_eof(parent);
1519 static int subflow_ulp_init(struct sock *sk)
1521 struct inet_connection_sock *icsk = inet_csk(sk);
1522 struct mptcp_subflow_context *ctx;
1523 struct tcp_sock *tp = tcp_sk(sk);
1526 /* disallow attaching ULP to a socket unless it has been
1527 * created with sock_create_kern()
1529 if (!sk->sk_kern_sock) {
1534 ctx = subflow_create_ctx(sk, GFP_KERNEL);
1540 pr_debug("subflow=%p, family=%d", ctx, sk->sk_family);
1543 ctx->icsk_af_ops = icsk->icsk_af_ops;
1544 icsk->icsk_af_ops = subflow_default_af_ops(sk);
1545 ctx->tcp_data_ready = sk->sk_data_ready;
1546 ctx->tcp_state_change = sk->sk_state_change;
1547 ctx->tcp_write_space = sk->sk_write_space;
1548 ctx->tcp_error_report = sk->sk_error_report;
1549 sk->sk_data_ready = subflow_data_ready;
1550 sk->sk_write_space = subflow_write_space;
1551 sk->sk_state_change = subflow_state_change;
1552 sk->sk_error_report = subflow_error_report;
1557 static void subflow_ulp_release(struct sock *ssk)
1559 struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(ssk);
1560 bool release = true;
1568 /* if the msk has been orphaned, keep the ctx
1569 * alive, will be freed by __mptcp_close_ssk(),
1570 * when the subflow is still unaccepted
1572 release = ctx->disposable || list_empty(&ctx->node);
1576 mptcp_subflow_ops_undo_override(ssk);
1578 kfree_rcu(ctx, rcu);
1581 static void subflow_ulp_clone(const struct request_sock *req,
1583 const gfp_t priority)
1585 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
1586 struct mptcp_subflow_context *old_ctx = mptcp_subflow_ctx(newsk);
1587 struct mptcp_subflow_context *new_ctx;
1589 if (!tcp_rsk(req)->is_mptcp ||
1590 (!subflow_req->mp_capable && !subflow_req->mp_join)) {
1591 subflow_ulp_fallback(newsk, old_ctx);
1595 new_ctx = subflow_create_ctx(newsk, priority);
1597 subflow_ulp_fallback(newsk, old_ctx);
1601 new_ctx->conn_finished = 1;
1602 new_ctx->icsk_af_ops = old_ctx->icsk_af_ops;
1603 new_ctx->tcp_data_ready = old_ctx->tcp_data_ready;
1604 new_ctx->tcp_state_change = old_ctx->tcp_state_change;
1605 new_ctx->tcp_write_space = old_ctx->tcp_write_space;
1606 new_ctx->tcp_error_report = old_ctx->tcp_error_report;
1607 new_ctx->rel_write_seq = 1;
1608 new_ctx->tcp_sock = newsk;
1610 if (subflow_req->mp_capable) {
1611 /* see comments in subflow_syn_recv_sock(), MPTCP connection
1612 * is fully established only after we receive the remote key
1614 new_ctx->mp_capable = 1;
1615 new_ctx->local_key = subflow_req->local_key;
1616 new_ctx->token = subflow_req->token;
1617 new_ctx->ssn_offset = subflow_req->ssn_offset;
1618 new_ctx->idsn = subflow_req->idsn;
1619 } else if (subflow_req->mp_join) {
1620 new_ctx->ssn_offset = subflow_req->ssn_offset;
1621 new_ctx->mp_join = 1;
1622 new_ctx->fully_established = 1;
1623 new_ctx->backup = subflow_req->backup;
1624 new_ctx->local_id = subflow_req->local_id;
1625 new_ctx->remote_id = subflow_req->remote_id;
1626 new_ctx->token = subflow_req->token;
1627 new_ctx->thmac = subflow_req->thmac;
1631 static void tcp_release_cb_override(struct sock *ssk)
1633 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1635 if (mptcp_subflow_has_delegated_action(subflow))
1636 mptcp_subflow_process_delegated(ssk);
1638 tcp_release_cb(ssk);
1641 static struct tcp_ulp_ops subflow_ulp_ops __read_mostly = {
1643 .owner = THIS_MODULE,
1644 .init = subflow_ulp_init,
1645 .release = subflow_ulp_release,
1646 .clone = subflow_ulp_clone,
1649 static int subflow_ops_init(struct request_sock_ops *subflow_ops)
1651 subflow_ops->obj_size = sizeof(struct mptcp_subflow_request_sock);
1652 subflow_ops->slab_name = "request_sock_subflow";
1654 subflow_ops->slab = kmem_cache_create(subflow_ops->slab_name,
1655 subflow_ops->obj_size, 0,
1657 SLAB_TYPESAFE_BY_RCU,
1659 if (!subflow_ops->slab)
1662 subflow_ops->destructor = subflow_req_destructor;
1667 void __init mptcp_subflow_init(void)
1669 mptcp_subflow_request_sock_ops = tcp_request_sock_ops;
1670 if (subflow_ops_init(&mptcp_subflow_request_sock_ops) != 0)
1671 panic("MPTCP: failed to init subflow request sock ops\n");
1673 subflow_request_sock_ipv4_ops = tcp_request_sock_ipv4_ops;
1674 subflow_request_sock_ipv4_ops.route_req = subflow_v4_route_req;
1676 subflow_specific = ipv4_specific;
1677 subflow_specific.conn_request = subflow_v4_conn_request;
1678 subflow_specific.syn_recv_sock = subflow_syn_recv_sock;
1679 subflow_specific.sk_rx_dst_set = subflow_finish_connect;
1681 tcp_prot_override = tcp_prot;
1682 tcp_prot_override.release_cb = tcp_release_cb_override;
1684 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1685 subflow_request_sock_ipv6_ops = tcp_request_sock_ipv6_ops;
1686 subflow_request_sock_ipv6_ops.route_req = subflow_v6_route_req;
1688 subflow_v6_specific = ipv6_specific;
1689 subflow_v6_specific.conn_request = subflow_v6_conn_request;
1690 subflow_v6_specific.syn_recv_sock = subflow_syn_recv_sock;
1691 subflow_v6_specific.sk_rx_dst_set = subflow_finish_connect;
1693 subflow_v6m_specific = subflow_v6_specific;
1694 subflow_v6m_specific.queue_xmit = ipv4_specific.queue_xmit;
1695 subflow_v6m_specific.send_check = ipv4_specific.send_check;
1696 subflow_v6m_specific.net_header_len = ipv4_specific.net_header_len;
1697 subflow_v6m_specific.mtu_reduced = ipv4_specific.mtu_reduced;
1698 subflow_v6m_specific.net_frag_header_len = 0;
1700 tcpv6_prot_override = tcpv6_prot;
1701 tcpv6_prot_override.release_cb = tcp_release_cb_override;
1704 mptcp_diag_subflow_init(&subflow_ulp_ops);
1706 if (tcp_register_ulp(&subflow_ulp_ops) != 0)
1707 panic("MPTCP: failed to register subflows to ULP\n");