| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Paolo Abeni | 2866 | 29.87% | 95 | 37.40% |
| Peter Krystad | 2844 | 29.64% | 9 | 3.54% |
| Mat Martineau | 1330 | 13.86% | 13 | 5.12% |
| Florian Westphal | 836 | 8.71% | 23 | 9.06% |
| Geliang Tang | 530 | 5.52% | 24 | 9.45% |
| Dmytro Shytyi | 219 | 2.28% | 2 | 0.79% |
| Matthieu Baerts | 217 | 2.26% | 4 | 1.57% |
| Davide Caratti | 181 | 1.89% | 7 | 2.76% |
| Nicolas Rybowski | 125 | 1.30% | 1 | 0.39% |
| Linus Torvalds (pre-git) | 105 | 1.09% | 18 | 7.09% |
| Arnaldo Carvalho de Melo | 64 | 0.67% | 6 | 2.36% |
| Eric Dumazet | 57 | 0.59% | 13 | 5.12% |
| Christoph Paasch | 54 | 0.56% | 3 | 1.18% |
| Octavian Purdila | 25 | 0.26% | 2 | 0.79% |
| Todd Malsbary | 21 | 0.22% | 1 | 0.39% |
| Hideaki Yoshifuji / 吉藤英明 | 20 | 0.21% | 5 | 1.97% |
| Jianguo Wu | 17 | 0.18% | 3 | 1.18% |
| Kishen Maloor | 12 | 0.13% | 3 | 1.18% |
| Neal Cardwell | 10 | 0.10% | 1 | 0.39% |
| Jakub Kiciński | 9 | 0.09% | 1 | 0.39% |
| Joe Perches | 6 | 0.06% | 1 | 0.39% |
| Gui Jianfeng | 5 | 0.05% | 1 | 0.39% |
| Chris Elston | 5 | 0.05% | 1 | 0.39% |
| Peilin Ye | 5 | 0.05% | 1 | 0.39% |
| Wei Yongjun | 4 | 0.04% | 1 | 0.39% |
| Denis V. Lunev | 3 | 0.03% | 1 | 0.39% |
| Jiri Benc | 3 | 0.03% | 1 | 0.39% |
| Geert Uytterhoeven | 3 | 0.03% | 1 | 0.39% |
| Satoru Moriya | 3 | 0.03% | 1 | 0.39% |
| Kazunori Miyazawa | 2 | 0.02% | 1 | 0.39% |
| Dave Jones | 2 | 0.02% | 1 | 0.39% |
| Daniel Lezcano | 2 | 0.02% | 1 | 0.39% |
| Herbert Xu | 2 | 0.02% | 1 | 0.39% |
| David S. Miller | 2 | 0.02% | 1 | 0.39% |
| Rusty Russell | 1 | 0.01% | 1 | 0.39% |
| Menglong Dong | 1 | 0.01% | 1 | 0.39% |
| Alexey Dobriyan | 1 | 0.01% | 1 | 0.39% |
| Hannes Frederic Sowa | 1 | 0.01% | 1 | 0.39% |
| Brian Haley | 1 | 0.01% | 1 | 0.39% |
| Bhaskar Chowdhury | 1 | 0.01% | 1 | 0.39% |
| Total | 9595 | 254 |
// SPDX-License-Identifier: GPL-2.0 /* Multipath TCP * * Copyright (c) 2017 - 2019, Intel Corporation. */ #define pr_fmt(fmt) "MPTCP: " fmt #include <linux/kernel.h> #include <linux/module.h> #include <linux/netdevice.h> #include <crypto/sha2.h> #include <crypto/utils.h> #include <net/sock.h> #include <net/inet_common.h> #include <net/inet_hashtables.h> #include <net/protocol.h> #include <net/tcp.h> #if IS_ENABLED(CONFIG_MPTCP_IPV6) #include <net/ip6_route.h> #include <net/transp_v6.h> #endif #include <net/mptcp.h> #include <uapi/linux/mptcp.h> #include "protocol.h" #include "mib.h" #include <trace/events/mptcp.h> #include <trace/events/sock.h> static void mptcp_subflow_ops_undo_override(struct sock *ssk); static void SUBFLOW_REQ_INC_STATS(struct request_sock *req, enum linux_mptcp_mib_field field) { MPTCP_INC_STATS(sock_net(req_to_sk(req)), field); } static void subflow_req_destructor(struct request_sock *req) { struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); pr_debug("subflow_req=%p", subflow_req); if (subflow_req->msk) sock_put((struct sock *)subflow_req->msk); mptcp_token_destroy_request(req); } static void subflow_generate_hmac(u64 key1, u64 key2, u32 nonce1, u32 nonce2, void *hmac) { u8 msg[8]; put_unaligned_be32(nonce1, &msg[0]); put_unaligned_be32(nonce2, &msg[4]); mptcp_crypto_hmac_sha(key1, key2, msg, 8, hmac); } static bool mptcp_can_accept_new_subflow(const struct mptcp_sock *msk) { return mptcp_is_fully_established((void *)msk) && ((mptcp_pm_is_userspace(msk) && mptcp_userspace_pm_active(msk)) || READ_ONCE(msk->pm.accept_subflow)); } /* validate received token and create truncated hmac and nonce for SYN-ACK */ static void subflow_req_create_thmac(struct mptcp_subflow_request_sock *subflow_req) { struct mptcp_sock *msk = subflow_req->msk; u8 hmac[SHA256_DIGEST_SIZE]; get_random_bytes(&subflow_req->local_nonce, sizeof(u32)); subflow_generate_hmac(msk->local_key, msk->remote_key, subflow_req->local_nonce, subflow_req->remote_nonce, hmac); subflow_req->thmac = get_unaligned_be64(hmac); } static struct mptcp_sock *subflow_token_join_request(struct request_sock *req) { struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); struct mptcp_sock *msk; int local_id; msk = mptcp_token_get_sock(sock_net(req_to_sk(req)), subflow_req->token); if (!msk) { SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINNOTOKEN); return NULL; } local_id = mptcp_pm_get_local_id(msk, (struct sock_common *)req); if (local_id < 0) { sock_put((struct sock *)msk); return NULL; } subflow_req->local_id = local_id; return msk; } static void subflow_init_req(struct request_sock *req, const struct sock *sk_listener) { struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); subflow_req->mp_capable = 0; subflow_req->mp_join = 0; subflow_req->csum_reqd = mptcp_is_checksum_enabled(sock_net(sk_listener)); subflow_req->allow_join_id0 = mptcp_allow_join_id0(sock_net(sk_listener)); subflow_req->msk = NULL; mptcp_token_init_request(req); } static bool subflow_use_different_sport(struct mptcp_sock *msk, const struct sock *sk) { return inet_sk(sk)->inet_sport != inet_sk((struct sock *)msk)->inet_sport; } static void subflow_add_reset_reason(struct sk_buff *skb, u8 reason) { struct mptcp_ext *mpext = skb_ext_add(skb, SKB_EXT_MPTCP); if (mpext) { memset(mpext, 0, sizeof(*mpext)); mpext->reset_reason = reason; } } /* Init mptcp request socket. * * Returns an error code if a JOIN has failed and a TCP reset * should be sent. */ static int subflow_check_req(struct request_sock *req, const struct sock *sk_listener, struct sk_buff *skb) { struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener); struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); struct mptcp_options_received mp_opt; bool opt_mp_capable, opt_mp_join; pr_debug("subflow_req=%p, listener=%p", subflow_req, listener); #ifdef CONFIG_TCP_MD5SIG /* no MPTCP if MD5SIG is enabled on this socket or we may run out of * TCP option space. */ if (rcu_access_pointer(tcp_sk(sk_listener)->md5sig_info)) return -EINVAL; #endif mptcp_get_options(skb, &mp_opt); opt_mp_capable = !!(mp_opt.suboptions & OPTIONS_MPTCP_MPC); opt_mp_join = !!(mp_opt.suboptions & OPTIONS_MPTCP_MPJ); if (opt_mp_capable) { SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MPCAPABLEPASSIVE); if (opt_mp_join) return 0; } else if (opt_mp_join) { SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINSYNRX); } if (opt_mp_capable && listener->request_mptcp) { int err, retries = MPTCP_TOKEN_MAX_RETRIES; subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq; again: do { get_random_bytes(&subflow_req->local_key, sizeof(subflow_req->local_key)); } while (subflow_req->local_key == 0); if (unlikely(req->syncookie)) { mptcp_crypto_key_sha(subflow_req->local_key, &subflow_req->token, &subflow_req->idsn); if (mptcp_token_exists(subflow_req->token)) { if (retries-- > 0) goto again; SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_TOKENFALLBACKINIT); } else { subflow_req->mp_capable = 1; } return 0; } err = mptcp_token_new_request(req); if (err == 0) subflow_req->mp_capable = 1; else if (retries-- > 0) goto again; else SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_TOKENFALLBACKINIT); } else if (opt_mp_join && listener->request_mptcp) { subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq; subflow_req->mp_join = 1; subflow_req->backup = mp_opt.backup; subflow_req->remote_id = mp_opt.join_id; subflow_req->token = mp_opt.token; subflow_req->remote_nonce = mp_opt.nonce; subflow_req->msk = subflow_token_join_request(req); /* Can't fall back to TCP in this case. */ if (!subflow_req->msk) { subflow_add_reset_reason(skb, MPTCP_RST_EMPTCP); return -EPERM; } if (subflow_use_different_sport(subflow_req->msk, sk_listener)) { pr_debug("syn inet_sport=%d %d", ntohs(inet_sk(sk_listener)->inet_sport), ntohs(inet_sk((struct sock *)subflow_req->msk)->inet_sport)); if (!mptcp_pm_sport_in_anno_list(subflow_req->msk, sk_listener)) { SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MISMATCHPORTSYNRX); return -EPERM; } SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINPORTSYNRX); } subflow_req_create_thmac(subflow_req); if (unlikely(req->syncookie)) { if (mptcp_can_accept_new_subflow(subflow_req->msk)) subflow_init_req_cookie_join_save(subflow_req, skb); else return -EPERM; } pr_debug("token=%u, remote_nonce=%u msk=%p", subflow_req->token, subflow_req->remote_nonce, subflow_req->msk); } return 0; } int mptcp_subflow_init_cookie_req(struct request_sock *req, const struct sock *sk_listener, struct sk_buff *skb) { struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener); struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); struct mptcp_options_received mp_opt; bool opt_mp_capable, opt_mp_join; int err; subflow_init_req(req, sk_listener); mptcp_get_options(skb, &mp_opt); opt_mp_capable = !!(mp_opt.suboptions & OPTIONS_MPTCP_MPC); opt_mp_join = !!(mp_opt.suboptions & OPTIONS_MPTCP_MPJ); if (opt_mp_capable && opt_mp_join) return -EINVAL; if (opt_mp_capable && listener->request_mptcp) { if (mp_opt.sndr_key == 0) return -EINVAL; subflow_req->local_key = mp_opt.rcvr_key; err = mptcp_token_new_request(req); if (err) return err; subflow_req->mp_capable = 1; subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1; } else if (opt_mp_join && listener->request_mptcp) { if (!mptcp_token_join_cookie_init_state(subflow_req, skb)) return -EINVAL; subflow_req->mp_join = 1; subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1; } return 0; } EXPORT_SYMBOL_GPL(mptcp_subflow_init_cookie_req); static struct dst_entry *subflow_v4_route_req(const struct sock *sk, struct sk_buff *skb, struct flowi *fl, struct request_sock *req) { struct dst_entry *dst; int err; tcp_rsk(req)->is_mptcp = 1; subflow_init_req(req, sk); dst = tcp_request_sock_ipv4_ops.route_req(sk, skb, fl, req); if (!dst) return NULL; err = subflow_check_req(req, sk, skb); if (err == 0) return dst; dst_release(dst); if (!req->syncookie) tcp_request_sock_ops.send_reset(sk, skb); return NULL; } static void subflow_prep_synack(const struct sock *sk, struct request_sock *req, struct tcp_fastopen_cookie *foc, enum tcp_synack_type synack_type) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); struct inet_request_sock *ireq = inet_rsk(req); /* clear tstamp_ok, as needed depending on cookie */ if (foc && foc->len > -1) ireq->tstamp_ok = 0; if (synack_type == TCP_SYNACK_FASTOPEN) mptcp_fastopen_subflow_synack_set_params(subflow, req); } static int subflow_v4_send_synack(const struct sock *sk, struct dst_entry *dst, struct flowi *fl, struct request_sock *req, struct tcp_fastopen_cookie *foc, enum tcp_synack_type synack_type, struct sk_buff *syn_skb) { subflow_prep_synack(sk, req, foc, synack_type); return tcp_request_sock_ipv4_ops.send_synack(sk, dst, fl, req, foc, synack_type, syn_skb); } #if IS_ENABLED(CONFIG_MPTCP_IPV6) static int subflow_v6_send_synack(const struct sock *sk, struct dst_entry *dst, struct flowi *fl, struct request_sock *req, struct tcp_fastopen_cookie *foc, enum tcp_synack_type synack_type, struct sk_buff *syn_skb) { subflow_prep_synack(sk, req, foc, synack_type); return tcp_request_sock_ipv6_ops.send_synack(sk, dst, fl, req, foc, synack_type, syn_skb); } static struct dst_entry *subflow_v6_route_req(const struct sock *sk, struct sk_buff *skb, struct flowi *fl, struct request_sock *req) { struct dst_entry *dst; int err; tcp_rsk(req)->is_mptcp = 1; subflow_init_req(req, sk); dst = tcp_request_sock_ipv6_ops.route_req(sk, skb, fl, req); if (!dst) return NULL; err = subflow_check_req(req, sk, skb); if (err == 0) return dst; dst_release(dst); if (!req->syncookie) tcp6_request_sock_ops.send_reset(sk, skb); return NULL; } #endif /* validate received truncated hmac and create hmac for third ACK */ static bool subflow_thmac_valid(struct mptcp_subflow_context *subflow) { u8 hmac[SHA256_DIGEST_SIZE]; u64 thmac; subflow_generate_hmac(subflow->remote_key, subflow->local_key, subflow->remote_nonce, subflow->local_nonce, hmac); thmac = get_unaligned_be64(hmac); pr_debug("subflow=%p, token=%u, thmac=%llu, subflow->thmac=%llu\n", subflow, subflow->token, thmac, subflow->thmac); return thmac == subflow->thmac; } void mptcp_subflow_reset(struct sock *ssk) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); struct sock *sk = subflow->conn; /* mptcp_mp_fail_no_response() can reach here on an already closed * socket */ if (ssk->sk_state == TCP_CLOSE) return; /* must hold: tcp_done() could drop last reference on parent */ sock_hold(sk); tcp_send_active_reset(ssk, GFP_ATOMIC); tcp_done(ssk); if (!test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &mptcp_sk(sk)->flags)) mptcp_schedule_work(sk); sock_put(sk); } static bool subflow_use_different_dport(struct mptcp_sock *msk, const struct sock *sk) { return inet_sk(sk)->inet_dport != inet_sk((struct sock *)msk)->inet_dport; } void __mptcp_sync_state(struct sock *sk, int state) { struct mptcp_sock *msk = mptcp_sk(sk); __mptcp_propagate_sndbuf(sk, msk->first); if (sk->sk_state == TCP_SYN_SENT) { inet_sk_state_store(sk, state); sk->sk_state_change(sk); } } static void mptcp_propagate_state(struct sock *sk, struct sock *ssk) { struct mptcp_sock *msk = mptcp_sk(sk); mptcp_data_lock(sk); if (!sock_owned_by_user(sk)) { __mptcp_sync_state(sk, ssk->sk_state); } else { msk->pending_state = ssk->sk_state; __set_bit(MPTCP_SYNC_STATE, &msk->cb_flags); } mptcp_data_unlock(sk); } static void subflow_set_remote_key(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow, const struct mptcp_options_received *mp_opt) { /* active MPC subflow will reach here multiple times: * at subflow_finish_connect() time and at 4th ack time */ if (subflow->remote_key_valid) return; subflow->remote_key_valid = 1; subflow->remote_key = mp_opt->sndr_key; mptcp_crypto_key_sha(subflow->remote_key, NULL, &subflow->iasn); subflow->iasn++; WRITE_ONCE(msk->remote_key, subflow->remote_key); WRITE_ONCE(msk->ack_seq, subflow->iasn); WRITE_ONCE(msk->can_ack, true); atomic64_set(&msk->rcv_wnd_sent, subflow->iasn); } static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); struct mptcp_options_received mp_opt; struct sock *parent = subflow->conn; struct mptcp_sock *msk; subflow->icsk_af_ops->sk_rx_dst_set(sk, skb); /* be sure no special action on any packet other than syn-ack */ if (subflow->conn_finished) return; msk = mptcp_sk(parent); subflow->rel_write_seq = 1; subflow->conn_finished = 1; subflow->ssn_offset = TCP_SKB_CB(skb)->seq; pr_debug("subflow=%p synack seq=%x", subflow, subflow->ssn_offset); mptcp_get_options(skb, &mp_opt); if (subflow->request_mptcp) { if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPC)) { MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVEFALLBACK); mptcp_do_fallback(sk); pr_fallback(msk); goto fallback; } if (mp_opt.suboptions & OPTION_MPTCP_CSUMREQD) WRITE_ONCE(msk->csum_enabled, true); if (mp_opt.deny_join_id0) WRITE_ONCE(msk->pm.remote_deny_join_id0, true); subflow->mp_capable = 1; subflow_set_remote_key(msk, subflow, &mp_opt); MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVEACK); mptcp_finish_connect(sk); mptcp_propagate_state(parent, sk); } else if (subflow->request_join) { u8 hmac[SHA256_DIGEST_SIZE]; if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPJ)) { subflow->reset_reason = MPTCP_RST_EMPTCP; goto do_reset; } subflow->backup = mp_opt.backup; subflow->thmac = mp_opt.thmac; subflow->remote_nonce = mp_opt.nonce; subflow->remote_id = mp_opt.join_id; pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u backup=%d", subflow, subflow->thmac, subflow->remote_nonce, subflow->backup); if (!subflow_thmac_valid(subflow)) { MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINACKMAC); subflow->reset_reason = MPTCP_RST_EMPTCP; goto do_reset; } if (!mptcp_finish_join(sk)) goto do_reset; subflow_generate_hmac(subflow->local_key, subflow->remote_key, subflow->local_nonce, subflow->remote_nonce, hmac); memcpy(subflow->hmac, hmac, MPTCPOPT_HMAC_LEN); subflow->mp_join = 1; MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNACKRX); if (subflow_use_different_dport(msk, sk)) { pr_debug("synack inet_dport=%d %d", ntohs(inet_sk(sk)->inet_dport), ntohs(inet_sk(parent)->inet_dport)); MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINPORTSYNACKRX); } } else if (mptcp_check_fallback(sk)) { fallback: mptcp_rcv_space_init(msk, sk); mptcp_propagate_state(parent, sk); } return; do_reset: subflow->reset_transient = 0; mptcp_subflow_reset(sk); } static void subflow_set_local_id(struct mptcp_subflow_context *subflow, int local_id) { subflow->local_id = local_id; subflow->local_id_valid = 1; } static int subflow_chk_local_id(struct sock *sk) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); struct mptcp_sock *msk = mptcp_sk(subflow->conn); int err; if (likely(subflow->local_id_valid)) return 0; err = mptcp_pm_get_local_id(msk, (struct sock_common *)sk); if (err < 0) return err; subflow_set_local_id(subflow, err); return 0; } static int subflow_rebuild_header(struct sock *sk) { int err = subflow_chk_local_id(sk); if (unlikely(err < 0)) return err; return inet_sk_rebuild_header(sk); } #if IS_ENABLED(CONFIG_MPTCP_IPV6) static int subflow_v6_rebuild_header(struct sock *sk) { int err = subflow_chk_local_id(sk); if (unlikely(err < 0)) return err; return inet6_sk_rebuild_header(sk); } #endif static struct request_sock_ops mptcp_subflow_v4_request_sock_ops __ro_after_init; static struct tcp_request_sock_ops subflow_request_sock_ipv4_ops __ro_after_init; static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); pr_debug("subflow=%p", subflow); /* Never answer to SYNs sent to broadcast or multicast */ if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) goto drop; return tcp_conn_request(&mptcp_subflow_v4_request_sock_ops, &subflow_request_sock_ipv4_ops, sk, skb); drop: tcp_listendrop(sk); return 0; } static void subflow_v4_req_destructor(struct request_sock *req) { subflow_req_destructor(req); tcp_request_sock_ops.destructor(req); } #if IS_ENABLED(CONFIG_MPTCP_IPV6) static struct request_sock_ops mptcp_subflow_v6_request_sock_ops __ro_after_init; static struct tcp_request_sock_ops subflow_request_sock_ipv6_ops __ro_after_init; static struct inet_connection_sock_af_ops subflow_v6_specific __ro_after_init; static struct inet_connection_sock_af_ops subflow_v6m_specific __ro_after_init; static struct proto tcpv6_prot_override __ro_after_init; static int subflow_v6_conn_request(struct sock *sk, struct sk_buff *skb) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); pr_debug("subflow=%p", subflow); if (skb->protocol == htons(ETH_P_IP)) return subflow_v4_conn_request(sk, skb); if (!ipv6_unicast_destination(skb)) goto drop; if (ipv6_addr_v4mapped(&ipv6_hdr(skb)->saddr)) { __IP6_INC_STATS(sock_net(sk), NULL, IPSTATS_MIB_INHDRERRORS); return 0; } return tcp_conn_request(&mptcp_subflow_v6_request_sock_ops, &subflow_request_sock_ipv6_ops, sk, skb); drop: tcp_listendrop(sk); return 0; /* don't send reset */ } static void subflow_v6_req_destructor(struct request_sock *req) { subflow_req_destructor(req); tcp6_request_sock_ops.destructor(req); } #endif struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener, bool attach_listener) { if (ops->family == AF_INET) ops = &mptcp_subflow_v4_request_sock_ops; #if IS_ENABLED(CONFIG_MPTCP_IPV6) else if (ops->family == AF_INET6) ops = &mptcp_subflow_v6_request_sock_ops; #endif return inet_reqsk_alloc(ops, sk_listener, attach_listener); } EXPORT_SYMBOL(mptcp_subflow_reqsk_alloc); /* validate hmac received in third ACK */ static bool subflow_hmac_valid(const struct request_sock *req, const struct mptcp_options_received *mp_opt) { const struct mptcp_subflow_request_sock *subflow_req; u8 hmac[SHA256_DIGEST_SIZE]; struct mptcp_sock *msk; subflow_req = mptcp_subflow_rsk(req); msk = subflow_req->msk; if (!msk) return false; subflow_generate_hmac(msk->remote_key, msk->local_key, subflow_req->remote_nonce, subflow_req->local_nonce, hmac); return !crypto_memneq(hmac, mp_opt->hmac, MPTCPOPT_HMAC_LEN); } static void subflow_ulp_fallback(struct sock *sk, struct mptcp_subflow_context *old_ctx) { struct inet_connection_sock *icsk = inet_csk(sk); mptcp_subflow_tcp_fallback(sk, old_ctx); icsk->icsk_ulp_ops = NULL; rcu_assign_pointer(icsk->icsk_ulp_data, NULL); tcp_sk(sk)->is_mptcp = 0; mptcp_subflow_ops_undo_override(sk); } void mptcp_subflow_drop_ctx(struct sock *ssk) { struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(ssk); if (!ctx) return; list_del(&mptcp_subflow_ctx(ssk)->node); if (inet_csk(ssk)->icsk_ulp_ops) { subflow_ulp_fallback(ssk, ctx); if (ctx->conn) sock_put(ctx->conn); } kfree_rcu(ctx, rcu); } void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow, const struct mptcp_options_received *mp_opt) { struct mptcp_sock *msk = mptcp_sk(subflow->conn); subflow_set_remote_key(msk, subflow, mp_opt); subflow->fully_established = 1; WRITE_ONCE(msk->fully_established, true); if (subflow->is_mptfo) mptcp_fastopen_gen_msk_ackseq(msk, subflow, mp_opt); } static struct sock *subflow_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, struct request_sock *req, struct dst_entry *dst, struct request_sock *req_unhash, bool *own_req) { struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk); struct mptcp_subflow_request_sock *subflow_req; struct mptcp_options_received mp_opt; bool fallback, fallback_is_fatal; struct mptcp_sock *owner; struct sock *child; pr_debug("listener=%p, req=%p, conn=%p", listener, req, listener->conn); /* After child creation we must look for MPC even when options * are not parsed */ mp_opt.suboptions = 0; /* hopefully temporary handling for MP_JOIN+syncookie */ subflow_req = mptcp_subflow_rsk(req); fallback_is_fatal = tcp_rsk(req)->is_mptcp && subflow_req->mp_join; fallback = !tcp_rsk(req)->is_mptcp; if (fallback) goto create_child; /* if the sk is MP_CAPABLE, we try to fetch the client key */ if (subflow_req->mp_capable) { /* we can receive and accept an in-window, out-of-order pkt, * which may not carry the MP_CAPABLE opt even on mptcp enabled * paths: always try to extract the peer key, and fallback * for packets missing it. * Even OoO DSS packets coming legitly after dropped or * reordered MPC will cause fallback, but we don't have other * options. */ mptcp_get_options(skb, &mp_opt); if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPC)) fallback = true; } else if (subflow_req->mp_join) { mptcp_get_options(skb, &mp_opt); if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPJ) || !subflow_hmac_valid(req, &mp_opt) || !mptcp_can_accept_new_subflow(subflow_req->msk)) { SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC); fallback = true; } } create_child: child = listener->icsk_af_ops->syn_recv_sock(sk, skb, req, dst, req_unhash, own_req); if (child && *own_req) { struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(child); tcp_rsk(req)->drop_req = false; /* we need to fallback on ctx allocation failure and on pre-reqs * checking above. In the latter scenario we additionally need * to reset the context to non MPTCP status. */ if (!ctx || fallback) { if (fallback_is_fatal) { subflow_add_reset_reason(skb, MPTCP_RST_EMPTCP); goto dispose_child; } goto fallback; } /* ssk inherits options of listener sk */ ctx->setsockopt_seq = listener->setsockopt_seq; if (ctx->mp_capable) { ctx->conn = mptcp_sk_clone_init(listener->conn, &mp_opt, child, req); if (!ctx->conn) goto fallback; ctx->subflow_id = 1; owner = mptcp_sk(ctx->conn); mptcp_pm_new_connection(owner, child, 1); /* with OoO packets we can reach here without ingress * mpc option */ if (mp_opt.suboptions & OPTION_MPTCP_MPC_ACK) { mptcp_subflow_fully_established(ctx, &mp_opt); mptcp_pm_fully_established(owner, child); ctx->pm_notified = 1; } } else if (ctx->mp_join) { owner = subflow_req->msk; if (!owner) { subflow_add_reset_reason(skb, MPTCP_RST_EPROHIBIT); goto dispose_child; } /* move the msk reference ownership to the subflow */ subflow_req->msk = NULL; ctx->conn = (struct sock *)owner; if (subflow_use_different_sport(owner, sk)) { pr_debug("ack inet_sport=%d %d", ntohs(inet_sk(sk)->inet_sport), ntohs(inet_sk((struct sock *)owner)->inet_sport)); if (!mptcp_pm_sport_in_anno_list(owner, sk)) { SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MISMATCHPORTACKRX); goto dispose_child; } SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINPORTACKRX); } if (!mptcp_finish_join(child)) goto dispose_child; SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKRX); tcp_rsk(req)->drop_req = true; } } /* check for expected invariant - should never trigger, just help * catching eariler subtle bugs */ WARN_ON_ONCE(child && *own_req && tcp_sk(child)->is_mptcp && (!mptcp_subflow_ctx(child) || !mptcp_subflow_ctx(child)->conn)); return child; dispose_child: mptcp_subflow_drop_ctx(child); tcp_rsk(req)->drop_req = true; inet_csk_prepare_for_destroy_sock(child); tcp_done(child); req->rsk_ops->send_reset(sk, skb); /* The last child reference will be released by the caller */ return child; fallback: mptcp_subflow_drop_ctx(child); return child; } static struct inet_connection_sock_af_ops subflow_specific __ro_after_init; static struct proto tcp_prot_override __ro_after_init; enum mapping_status { MAPPING_OK, MAPPING_INVALID, MAPPING_EMPTY, MAPPING_DATA_FIN, MAPPING_DUMMY, MAPPING_BAD_CSUM }; static void dbg_bad_map(struct mptcp_subflow_context *subflow, u32 ssn) { pr_debug("Bad mapping: ssn=%d map_seq=%d map_data_len=%d", ssn, subflow->map_subflow_seq, subflow->map_data_len); } static bool skb_is_fully_mapped(struct sock *ssk, struct sk_buff *skb) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); unsigned int skb_consumed; skb_consumed = tcp_sk(ssk)->copied_seq - TCP_SKB_CB(skb)->seq; if (WARN_ON_ONCE(skb_consumed >= skb->len)) return true; return skb->len - skb_consumed <= subflow->map_data_len - mptcp_subflow_get_map_offset(subflow); } static bool validate_mapping(struct sock *ssk, struct sk_buff *skb) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); u32 ssn = tcp_sk(ssk)->copied_seq - subflow->ssn_offset; if (unlikely(before(ssn, subflow->map_subflow_seq))) { /* Mapping covers data later in the subflow stream, * currently unsupported. */ dbg_bad_map(subflow, ssn); return false; } if (unlikely(!before(ssn, subflow->map_subflow_seq + subflow->map_data_len))) { /* Mapping does covers past subflow data, invalid */ dbg_bad_map(subflow, ssn); return false; } return true; } static enum mapping_status validate_data_csum(struct sock *ssk, struct sk_buff *skb, bool csum_reqd) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); u32 offset, seq, delta; __sum16 csum; int len; if (!csum_reqd) return MAPPING_OK; /* mapping already validated on previous traversal */ if (subflow->map_csum_len == subflow->map_data_len) return MAPPING_OK; /* traverse the receive queue, ensuring it contains a full * DSS mapping and accumulating the related csum. * Preserve the accoumlate csum across multiple calls, to compute * the csum only once */ delta = subflow->map_data_len - subflow->map_csum_len; for (;;) { seq = tcp_sk(ssk)->copied_seq + subflow->map_csum_len; offset = seq - TCP_SKB_CB(skb)->seq; /* if the current skb has not been accounted yet, csum its contents * up to the amount covered by the current DSS */ if (offset < skb->len) { __wsum csum; len = min(skb->len - offset, delta); csum = skb_checksum(skb, offset, len, 0); subflow->map_data_csum = csum_block_add(subflow->map_data_csum, csum, subflow->map_csum_len); delta -= len; subflow->map_csum_len += len; } if (delta == 0) break; if (skb_queue_is_last(&ssk->sk_receive_queue, skb)) { /* if this subflow is closed, the partial mapping * will be never completed; flush the pending skbs, so * that subflow_sched_work_if_closed() can kick in */ if (unlikely(ssk->sk_state == TCP_CLOSE)) while ((skb = skb_peek(&ssk->sk_receive_queue))) sk_eat_skb(ssk, skb); /* not enough data to validate the csum */ return MAPPING_EMPTY; } /* the DSS mapping for next skbs will be validated later, * when a get_mapping_status call will process such skb */ skb = skb->next; } /* note that 'map_data_len' accounts only for the carried data, does * not include the eventual seq increment due to the data fin, * while the pseudo header requires the original DSS data len, * including that */ csum = __mptcp_make_csum(subflow->map_seq, subflow->map_subflow_seq, subflow->map_data_len + subflow->map_data_fin, subflow->map_data_csum); if (unlikely(csum)) { MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DATACSUMERR); return MAPPING_BAD_CSUM; } subflow->valid_csum_seen = 1; return MAPPING_OK; } static enum mapping_status get_mapping_status(struct sock *ssk, struct mptcp_sock *msk) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); bool csum_reqd = READ_ONCE(msk->csum_enabled); struct mptcp_ext *mpext; struct sk_buff *skb; u16 data_len; u64 map_seq; skb = skb_peek(&ssk->sk_receive_queue); if (!skb) return MAPPING_EMPTY; if (mptcp_check_fallback(ssk)) return MAPPING_DUMMY; mpext = mptcp_get_ext(skb); if (!mpext || !mpext->use_map) { if (!subflow->map_valid && !skb->len) { /* the TCP stack deliver 0 len FIN pkt to the receive * queue, that is the only 0len pkts ever expected here, * and we can admit no mapping only for 0 len pkts */ if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) WARN_ONCE(1, "0len seq %d:%d flags %x", TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq, TCP_SKB_CB(skb)->tcp_flags); sk_eat_skb(ssk, skb); return MAPPING_EMPTY; } if (!subflow->map_valid) return MAPPING_INVALID; goto validate_seq; } trace_get_mapping_status(mpext); data_len = mpext->data_len; if (data_len == 0) { pr_debug("infinite mapping received"); MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPRX); subflow->map_data_len = 0; return MAPPING_INVALID; } if (mpext->data_fin == 1) { if (data_len == 1) { bool updated = mptcp_update_rcv_data_fin(msk, mpext->data_seq, mpext->dsn64); pr_debug("DATA_FIN with no payload seq=%llu", mpext->data_seq); if (subflow->map_valid) { /* A DATA_FIN might arrive in a DSS * option before the previous mapping * has been fully consumed. Continue * handling the existing mapping. */ skb_ext_del(skb, SKB_EXT_MPTCP); return MAPPING_OK; } else { if (updated) mptcp_schedule_work((struct sock *)msk); return MAPPING_DATA_FIN; } } else { u64 data_fin_seq = mpext->data_seq + data_len - 1; /* If mpext->data_seq is a 32-bit value, data_fin_seq * must also be limited to 32 bits. */ if (!mpext->dsn64) data_fin_seq &= GENMASK_ULL(31, 0); mptcp_update_rcv_data_fin(msk, data_fin_seq, mpext->dsn64); pr_debug("DATA_FIN with mapping seq=%llu dsn64=%d", data_fin_seq, mpext->dsn64); } /* Adjust for DATA_FIN using 1 byte of sequence space */ data_len--; } map_seq = mptcp_expand_seq(READ_ONCE(msk->ack_seq), mpext->data_seq, mpext->dsn64); WRITE_ONCE(mptcp_sk(subflow->conn)->use_64bit_ack, !!mpext->dsn64); if (subflow->map_valid) { /* Allow replacing only with an identical map */ if (subflow->map_seq == map_seq && subflow->map_subflow_seq == mpext->subflow_seq && subflow->map_data_len == data_len && subflow->map_csum_reqd == mpext->csum_reqd) { skb_ext_del(skb, SKB_EXT_MPTCP); goto validate_csum; } /* If this skb data are fully covered by the current mapping, * the new map would need caching, which is not supported */ if (skb_is_fully_mapped(ssk, skb)) { MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DSSNOMATCH); return MAPPING_INVALID; } /* will validate the next map after consuming the current one */ goto validate_csum; } subflow->map_seq = map_seq; subflow->map_subflow_seq = mpext->subflow_seq; subflow->map_data_len = data_len; subflow->map_valid = 1; subflow->map_data_fin = mpext->data_fin; subflow->mpc_map = mpext->mpc_map; subflow->map_csum_reqd = mpext->csum_reqd; subflow->map_csum_len = 0; subflow->map_data_csum = csum_unfold(mpext->csum); /* Cfr RFC 8684 Section 3.3.0 */ if (unlikely(subflow->map_csum_reqd != csum_reqd)) return MAPPING_INVALID; pr_debug("new map seq=%llu subflow_seq=%u data_len=%u csum=%d:%u", subflow->map_seq, subflow->map_subflow_seq, subflow->map_data_len, subflow->map_csum_reqd, subflow->map_data_csum); validate_seq: /* we revalidate valid mapping on new skb, because we must ensure * the current skb is completely covered by the available mapping */ if (!validate_mapping(ssk, skb)) { MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DSSTCPMISMATCH); return MAPPING_INVALID; } skb_ext_del(skb, SKB_EXT_MPTCP); validate_csum: return validate_data_csum(ssk, skb, csum_reqd); } static void mptcp_subflow_discard_data(struct sock *ssk, struct sk_buff *skb, u64 limit) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); bool fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN; u32 incr; incr = limit >= skb->len ? skb->len + fin : limit; pr_debug("discarding=%d len=%d seq=%d", incr, skb->len, subflow->map_subflow_seq); MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DUPDATA); tcp_sk(ssk)->copied_seq += incr; if (!before(tcp_sk(ssk)->copied_seq, TCP_SKB_CB(skb)->end_seq)) sk_eat_skb(ssk, skb); if (mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len) subflow->map_valid = 0; } /* sched mptcp worker to remove the subflow if no more data is pending */ static void subflow_sched_work_if_closed(struct mptcp_sock *msk, struct sock *ssk) { if (likely(ssk->sk_state != TCP_CLOSE)) return; if (skb_queue_empty(&ssk->sk_receive_queue) && !test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags)) mptcp_schedule_work((struct sock *)msk); } static bool subflow_can_fallback(struct mptcp_subflow_context *subflow) { struct mptcp_sock *msk = mptcp_sk(subflow->conn); if (subflow->mp_join) return false; else if (READ_ONCE(msk->csum_enabled)) return !subflow->valid_csum_seen; else return !subflow->fully_established; } static void mptcp_subflow_fail(struct mptcp_sock *msk, struct sock *ssk) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); unsigned long fail_tout; /* greceful failure can happen only on the MPC subflow */ if (WARN_ON_ONCE(ssk != READ_ONCE(msk->first))) return; /* since the close timeout take precedence on the fail one, * no need to start the latter when the first is already set */ if (sock_flag((struct sock *)msk, SOCK_DEAD)) return; /* we don't need extreme accuracy here, use a zero fail_tout as special * value meaning no fail timeout at all; */ fail_tout = jiffies + TCP_RTO_MAX; if (!fail_tout) fail_tout = 1; WRITE_ONCE(subflow->fail_tout, fail_tout); tcp_send_ack(ssk); mptcp_reset_tout_timer(msk, subflow->fail_tout); } static bool subflow_check_data_avail(struct sock *ssk) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); enum mapping_status status; struct mptcp_sock *msk; struct sk_buff *skb; if (!skb_peek(&ssk->sk_receive_queue)) WRITE_ONCE(subflow->data_avail, false); if (subflow->data_avail) return true; msk = mptcp_sk(subflow->conn); for (;;) { u64 ack_seq; u64 old_ack; status = get_mapping_status(ssk, msk); trace_subflow_check_data_avail(status, skb_peek(&ssk->sk_receive_queue)); if (unlikely(status == MAPPING_INVALID || status == MAPPING_DUMMY || status == MAPPING_BAD_CSUM)) goto fallback; if (status != MAPPING_OK) goto no_data; skb = skb_peek(&ssk->sk_receive_queue); if (WARN_ON_ONCE(!skb)) goto no_data; if (unlikely(!READ_ONCE(msk->can_ack))) goto fallback; old_ack = READ_ONCE(msk->ack_seq); ack_seq = mptcp_subflow_get_mapped_dsn(subflow); pr_debug("msk ack_seq=%llx subflow ack_seq=%llx", old_ack, ack_seq); if (unlikely(before64(ack_seq, old_ack))) { mptcp_subflow_discard_data(ssk, skb, old_ack - ack_seq); continue; } WRITE_ONCE(subflow->data_avail, true); break; } return true; no_data: subflow_sched_work_if_closed(msk, ssk); return false; fallback: if (!__mptcp_check_fallback(msk)) { /* RFC 8684 section 3.7. */ if (status == MAPPING_BAD_CSUM && (subflow->mp_join || subflow->valid_csum_seen)) { subflow->send_mp_fail = 1; if (!READ_ONCE(msk->allow_infinite_fallback)) { subflow->reset_transient = 0; subflow->reset_reason = MPTCP_RST_EMIDDLEBOX; goto reset; } mptcp_subflow_fail(msk, ssk); WRITE_ONCE(subflow->data_avail, true); return true; } if (!subflow_can_fallback(subflow) && subflow->map_data_len) { /* fatal protocol error, close the socket. * subflow_error_report() will introduce the appropriate barriers */ subflow->reset_transient = 0; subflow->reset_reason = MPTCP_RST_EMPTCP; reset: WRITE_ONCE(ssk->sk_err, EBADMSG); tcp_set_state(ssk, TCP_CLOSE); while ((skb = skb_peek(&ssk->sk_receive_queue))) sk_eat_skb(ssk, skb); tcp_send_active_reset(ssk, GFP_ATOMIC); WRITE_ONCE(subflow->data_avail, false); return false; } mptcp_do_fallback(ssk); } skb = skb_peek(&ssk->sk_receive_queue); subflow->map_valid = 1; subflow->map_seq = READ_ONCE(msk->ack_seq); subflow->map_data_len = skb->len; subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq - subflow->ssn_offset; WRITE_ONCE(subflow->data_avail, true); return true; } bool mptcp_subflow_data_available(struct sock *sk) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); /* check if current mapping is still valid */ if (subflow->map_valid && mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len) { subflow->map_valid = 0; WRITE_ONCE(subflow->data_avail, false); pr_debug("Done with mapping: seq=%u data_len=%u", subflow->map_subflow_seq, subflow->map_data_len); } return subflow_check_data_avail(sk); } /* If ssk has an mptcp parent socket, use the mptcp rcvbuf occupancy, * not the ssk one. * * In mptcp, rwin is about the mptcp-level connection data. * * Data that is still on the ssk rx queue can thus be ignored, * as far as mptcp peer is concerned that data is still inflight. * DSS ACK is updated when skb is moved to the mptcp rx queue. */ void mptcp_space(const struct sock *ssk, int *space, int *full_space) { const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); const struct sock *sk = subflow->conn; *space = __mptcp_space(sk); *full_space = mptcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf)); } static void subflow_error_report(struct sock *ssk) { struct sock *sk = mptcp_subflow_ctx(ssk)->conn; /* bail early if this is a no-op, so that we avoid introducing a * problematic lockdep dependency between TCP accept queue lock * and msk socket spinlock */ if (!sk->sk_socket) return; mptcp_data_lock(sk); if (!sock_owned_by_user(sk)) __mptcp_error_report(sk); else __set_bit(MPTCP_ERROR_REPORT, &mptcp_sk(sk)->cb_flags); mptcp_data_unlock(sk); } static void subflow_data_ready(struct sock *sk) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); u16 state = 1 << inet_sk_state_load(sk); struct sock *parent = subflow->conn; struct mptcp_sock *msk; trace_sk_data_ready(sk); msk = mptcp_sk(parent); if (state & TCPF_LISTEN) { /* MPJ subflow are removed from accept queue before reaching here, * avoid stray wakeups */ if (reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue)) return; parent->sk_data_ready(parent); return; } WARN_ON_ONCE(!__mptcp_check_fallback(msk) && !subflow->mp_capable && !subflow->mp_join && !(state & TCPF_CLOSE)); if (mptcp_subflow_data_available(sk)) { mptcp_data_ready(parent, sk); /* subflow-level lowat test are not relevant. * respect the msk-level threshold eventually mandating an immediate ack */ if (mptcp_data_avail(msk) < parent->sk_rcvlowat && (tcp_sk(sk)->rcv_nxt - tcp_sk(sk)->rcv_wup) > inet_csk(sk)->icsk_ack.rcv_mss) inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_NOW; } else if (unlikely(sk->sk_err)) { subflow_error_report(sk); } } static void subflow_write_space(struct sock *ssk) { struct sock *sk = mptcp_subflow_ctx(ssk)->conn; mptcp_propagate_sndbuf(sk, ssk); mptcp_write_space(sk); } static const struct inet_connection_sock_af_ops * subflow_default_af_ops(struct sock *sk) { #if IS_ENABLED(CONFIG_MPTCP_IPV6) if (sk->sk_family == AF_INET6) return &subflow_v6_specific; #endif return &subflow_specific; } #if IS_ENABLED(CONFIG_MPTCP_IPV6) void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); struct inet_connection_sock *icsk = inet_csk(sk); const struct inet_connection_sock_af_ops *target; target = mapped ? &subflow_v6m_specific : subflow_default_af_ops(sk); pr_debug("subflow=%p family=%d ops=%p target=%p mapped=%d", subflow, sk->sk_family, icsk->icsk_af_ops, target, mapped); if (likely(icsk->icsk_af_ops == target)) return; subflow->icsk_af_ops = icsk->icsk_af_ops; icsk->icsk_af_ops = target; } #endif void mptcp_info2sockaddr(const struct mptcp_addr_info *info, struct sockaddr_storage *addr, unsigned short family) { memset(addr, 0, sizeof(*addr)); addr->ss_family = family; if (addr->ss_family == AF_INET) { struct sockaddr_in *in_addr = (struct sockaddr_in *)addr; if (info->family == AF_INET) in_addr->sin_addr = info->addr; #if IS_ENABLED(CONFIG_MPTCP_IPV6) else if (ipv6_addr_v4mapped(&info->addr6)) in_addr->sin_addr.s_addr = info->addr6.s6_addr32[3]; #endif in_addr->sin_port = info->port; } #if IS_ENABLED(CONFIG_MPTCP_IPV6) else if (addr->ss_family == AF_INET6) { struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)addr; if (info->family == AF_INET) ipv6_addr_set_v4mapped(info->addr.s_addr, &in6_addr->sin6_addr); else in6_addr->sin6_addr = info->addr6; in6_addr->sin6_port = info->port; } #endif } int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc, const struct mptcp_addr_info *remote) { struct mptcp_sock *msk = mptcp_sk(sk); struct mptcp_subflow_context *subflow; struct sockaddr_storage addr; int remote_id = remote->id; int local_id = loc->id; int err = -ENOTCONN; struct socket *sf; struct sock *ssk; u32 remote_token; int addrlen; int ifindex; u8 flags; if (!mptcp_is_fully_established(sk)) goto err_out; err = mptcp_subflow_create_socket(sk, loc->family, &sf); if (err) goto err_out; ssk = sf->sk; subflow = mptcp_subflow_ctx(ssk); do { get_random_bytes(&subflow->local_nonce, sizeof(u32)); } while (!subflow->local_nonce); if (local_id) subflow_set_local_id(subflow, local_id); mptcp_pm_get_flags_and_ifindex_by_id(msk, local_id, &flags, &ifindex); subflow->remote_key_valid = 1; subflow->remote_key = msk->remote_key; subflow->local_key = msk->local_key; subflow->token = msk->token; mptcp_info2sockaddr(loc, &addr, ssk->sk_family); addrlen = sizeof(struct sockaddr_in); #if IS_ENABLED(CONFIG_MPTCP_IPV6) if (addr.ss_family == AF_INET6) addrlen = sizeof(struct sockaddr_in6); #endif ssk->sk_bound_dev_if = ifindex; err = kernel_bind(sf, (struct sockaddr *)&addr, addrlen); if (err) goto failed; mptcp_crypto_key_sha(subflow->remote_key, &remote_token, NULL); pr_debug("msk=%p remote_token=%u local_id=%d remote_id=%d", msk, remote_token, local_id, remote_id); subflow->remote_token = remote_token; subflow->remote_id = remote_id; subflow->request_join = 1; subflow->request_bkup = !!(flags & MPTCP_PM_ADDR_FLAG_BACKUP); subflow->subflow_id = msk->subflow_id++; mptcp_info2sockaddr(remote, &addr, ssk->sk_family); sock_hold(ssk); list_add_tail(&subflow->node, &msk->conn_list); err = kernel_connect(sf, (struct sockaddr *)&addr, addrlen, O_NONBLOCK); if (err && err != -EINPROGRESS) goto failed_unlink; /* discard the subflow socket */ mptcp_sock_graft(ssk, sk->sk_socket); iput(SOCK_INODE(sf)); WRITE_ONCE(msk->allow_infinite_fallback, false); mptcp_stop_tout_timer(sk); return 0; failed_unlink: list_del(&subflow->node); sock_put(mptcp_subflow_tcp_sock(subflow)); failed: subflow->disposable = 1; sock_release(sf); err_out: /* we account subflows before the creation, and this failures will not * be caught by sk_state_change() */ mptcp_pm_close_subflow(msk); return err; } static void mptcp_attach_cgroup(struct sock *parent, struct sock *child) { #ifdef CONFIG_SOCK_CGROUP_DATA struct sock_cgroup_data *parent_skcd = &parent->sk_cgrp_data, *child_skcd = &child->sk_cgrp_data; /* only the additional subflows created by kworkers have to be modified */ if (cgroup_id(sock_cgroup_ptr(parent_skcd)) != cgroup_id(sock_cgroup_ptr(child_skcd))) { #ifdef CONFIG_MEMCG struct mem_cgroup *memcg = parent->sk_memcg; mem_cgroup_sk_free(child); if (memcg && css_tryget(&memcg->css)) child->sk_memcg = memcg; #endif /* CONFIG_MEMCG */ cgroup_sk_free(child_skcd); *child_skcd = *parent_skcd; cgroup_sk_clone(child_skcd); } #endif /* CONFIG_SOCK_CGROUP_DATA */ } static void mptcp_subflow_ops_override(struct sock *ssk) { #if IS_ENABLED(CONFIG_MPTCP_IPV6) if (ssk->sk_prot == &tcpv6_prot) ssk->sk_prot = &tcpv6_prot_override; else #endif ssk->sk_prot = &tcp_prot_override; } static void mptcp_subflow_ops_undo_override(struct sock *ssk) { #if IS_ENABLED(CONFIG_MPTCP_IPV6) if (ssk->sk_prot == &tcpv6_prot_override) ssk->sk_prot = &tcpv6_prot; else #endif ssk->sk_prot = &tcp_prot; } int mptcp_subflow_create_socket(struct sock *sk, unsigned short family, struct socket **new_sock) { struct mptcp_subflow_context *subflow; struct net *net = sock_net(sk); struct socket *sf; int err; /* un-accepted server sockets can reach here - on bad configuration * bail early to avoid greater trouble later */ if (unlikely(!sk->sk_socket)) return -EINVAL; err = sock_create_kern(net, family, SOCK_STREAM, IPPROTO_TCP, &sf); if (err) return err; lock_sock_nested(sf->sk, SINGLE_DEPTH_NESTING); err = security_mptcp_add_subflow(sk, sf->sk); if (err) goto err_free; /* the newly created socket has to be in the same cgroup as its parent */ mptcp_attach_cgroup(sk, sf->sk); /* kernel sockets do not by default acquire net ref, but TCP timer * needs it. * Update ns_tracker to current stack trace and refcounted tracker. */ __netns_tracker_free(net, &sf->sk->ns_tracker, false); sf->sk->sk_net_refcnt = 1; get_net_track(net, &sf->sk->ns_tracker, GFP_KERNEL); sock_inuse_add(net, 1); err = tcp_set_ulp(sf->sk, "mptcp"); if (err) goto err_free; mptcp_sockopt_sync_locked(mptcp_sk(sk), sf->sk); release_sock(sf->sk); /* the newly created socket really belongs to the owning MPTCP master * socket, even if for additional subflows the allocation is performed * by a kernel workqueue. Adjust inode references, so that the * procfs/diag interfaces really show this one belonging to the correct * user. */ SOCK_INODE(sf)->i_ino = SOCK_INODE(sk->sk_socket)->i_ino; SOCK_INODE(sf)->i_uid = SOCK_INODE(sk->sk_socket)->i_uid; SOCK_INODE(sf)->i_gid = SOCK_INODE(sk->sk_socket)->i_gid; subflow = mptcp_subflow_ctx(sf->sk); pr_debug("subflow=%p", subflow); *new_sock = sf; sock_hold(sk); subflow->conn = sk; mptcp_subflow_ops_override(sf->sk); return 0; err_free: release_sock(sf->sk); sock_release(sf); return err; } static struct mptcp_subflow_context *subflow_create_ctx(struct sock *sk, gfp_t priority) { struct inet_connection_sock *icsk = inet_csk(sk); struct mptcp_subflow_context *ctx; ctx = kzalloc(sizeof(*ctx), priority); if (!ctx) return NULL; rcu_assign_pointer(icsk->icsk_ulp_data, ctx); INIT_LIST_HEAD(&ctx->node); INIT_LIST_HEAD(&ctx->delegated_node); pr_debug("subflow=%p", ctx); ctx->tcp_sock = sk; return ctx; } static void __subflow_state_change(struct sock *sk) { struct socket_wq *wq; rcu_read_lock(); wq = rcu_dereference(sk->sk_wq); if (skwq_has_sleeper(wq)) wake_up_interruptible_all(&wq->wait); rcu_read_unlock(); } static bool subflow_is_done(const struct sock *sk) { return sk->sk_shutdown & RCV_SHUTDOWN || sk->sk_state == TCP_CLOSE; } static void subflow_state_change(struct sock *sk) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); struct sock *parent = subflow->conn; struct mptcp_sock *msk; __subflow_state_change(sk); msk = mptcp_sk(parent); if (subflow_simultaneous_connect(sk)) { mptcp_do_fallback(sk); mptcp_rcv_space_init(msk, sk); pr_fallback(msk); subflow->conn_finished = 1; mptcp_propagate_state(parent, sk); } /* as recvmsg() does not acquire the subflow socket for ssk selection * a fin packet carrying a DSS can be unnoticed if we don't trigger * the data available machinery here. */ if (mptcp_subflow_data_available(sk)) mptcp_data_ready(parent, sk); else if (unlikely(sk->sk_err)) subflow_error_report(sk); subflow_sched_work_if_closed(mptcp_sk(parent), sk); /* when the fallback subflow closes the rx side, trigger a 'dummy' * ingress data fin, so that the msk state will follow along */ if (__mptcp_check_fallback(msk) && subflow_is_done(sk) && msk->first == sk && mptcp_update_rcv_data_fin(msk, READ_ONCE(msk->ack_seq), true)) mptcp_schedule_work(parent); } void mptcp_subflow_queue_clean(struct sock *listener_sk, struct sock *listener_ssk) { struct request_sock_queue *queue = &inet_csk(listener_ssk)->icsk_accept_queue; struct request_sock *req, *head, *tail; struct mptcp_subflow_context *subflow; struct sock *sk, *ssk; /* Due to lock dependencies no relevant lock can be acquired under rskq_lock. * Splice the req list, so that accept() can not reach the pending ssk after * the listener socket is released below. */ spin_lock_bh(&queue->rskq_lock); head = queue->rskq_accept_head; tail = queue->rskq_accept_tail; queue->rskq_accept_head = NULL; queue->rskq_accept_tail = NULL; spin_unlock_bh(&queue->rskq_lock); if (!head) return; /* can't acquire the msk socket lock under the subflow one, * or will cause ABBA deadlock */ release_sock(listener_ssk); for (req = head; req; req = req->dl_next) { ssk = req->sk; if (!sk_is_mptcp(ssk)) continue; subflow = mptcp_subflow_ctx(ssk); if (!subflow || !subflow->conn) continue; sk = subflow->conn; sock_hold(sk); lock_sock_nested(sk, SINGLE_DEPTH_NESTING); __mptcp_unaccepted_force_close(sk); release_sock(sk); /* lockdep will report a false positive ABBA deadlock * between cancel_work_sync and the listener socket. * The involved locks belong to different sockets WRT * the existing AB chain. * Using a per socket key is problematic as key * deregistration requires process context and must be * performed at socket disposal time, in atomic * context. * Just tell lockdep to consider the listener socket * released here. */ mutex_release(&listener_sk->sk_lock.dep_map, _RET_IP_); mptcp_cancel_work(sk); mutex_acquire(&listener_sk->sk_lock.dep_map, 0, 0, _RET_IP_); sock_put(sk); } /* we are still under the listener msk socket lock */ lock_sock_nested(listener_ssk, SINGLE_DEPTH_NESTING); /* restore the listener queue, to let the TCP code clean it up */ spin_lock_bh(&queue->rskq_lock); WARN_ON_ONCE(queue->rskq_accept_head); queue->rskq_accept_head = head; queue->rskq_accept_tail = tail; spin_unlock_bh(&queue->rskq_lock); } static int subflow_ulp_init(struct sock *sk) { struct inet_connection_sock *icsk = inet_csk(sk); struct mptcp_subflow_context *ctx; struct tcp_sock *tp = tcp_sk(sk); int err = 0; /* disallow attaching ULP to a socket unless it has been * created with sock_create_kern() */ if (!sk->sk_kern_sock) { err = -EOPNOTSUPP; goto out; } ctx = subflow_create_ctx(sk, GFP_KERNEL); if (!ctx) { err = -ENOMEM; goto out; } pr_debug("subflow=%p, family=%d", ctx, sk->sk_family); tp->is_mptcp = 1; ctx->icsk_af_ops = icsk->icsk_af_ops; icsk->icsk_af_ops = subflow_default_af_ops(sk); ctx->tcp_state_change = sk->sk_state_change; ctx->tcp_error_report = sk->sk_error_report; WARN_ON_ONCE(sk->sk_data_ready != sock_def_readable); WARN_ON_ONCE(sk->sk_write_space != sk_stream_write_space); sk->sk_data_ready = subflow_data_ready; sk->sk_write_space = subflow_write_space; sk->sk_state_change = subflow_state_change; sk->sk_error_report = subflow_error_report; out: return err; } static void subflow_ulp_release(struct sock *ssk) { struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(ssk); bool release = true; struct sock *sk; if (!ctx) return; sk = ctx->conn; if (sk) { /* if the msk has been orphaned, keep the ctx * alive, will be freed by __mptcp_close_ssk(), * when the subflow is still unaccepted */ release = ctx->disposable || list_empty(&ctx->node); /* inet_child_forget() does not call sk_state_change(), * explicitly trigger the socket close machinery */ if (!release && !test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &mptcp_sk(sk)->flags)) mptcp_schedule_work(sk); sock_put(sk); } mptcp_subflow_ops_undo_override(ssk); if (release) kfree_rcu(ctx, rcu); } static void subflow_ulp_clone(const struct request_sock *req, struct sock *newsk, const gfp_t priority) { struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); struct mptcp_subflow_context *old_ctx = mptcp_subflow_ctx(newsk); struct mptcp_subflow_context *new_ctx; if (!tcp_rsk(req)->is_mptcp || (!subflow_req->mp_capable && !subflow_req->mp_join)) { subflow_ulp_fallback(newsk, old_ctx); return; } new_ctx = subflow_create_ctx(newsk, priority); if (!new_ctx) { subflow_ulp_fallback(newsk, old_ctx); return; } new_ctx->conn_finished = 1; new_ctx->icsk_af_ops = old_ctx->icsk_af_ops; new_ctx->tcp_state_change = old_ctx->tcp_state_change; new_ctx->tcp_error_report = old_ctx->tcp_error_report; new_ctx->rel_write_seq = 1; new_ctx->tcp_sock = newsk; if (subflow_req->mp_capable) { /* see comments in subflow_syn_recv_sock(), MPTCP connection * is fully established only after we receive the remote key */ new_ctx->mp_capable = 1; new_ctx->local_key = subflow_req->local_key; new_ctx->token = subflow_req->token; new_ctx->ssn_offset = subflow_req->ssn_offset; new_ctx->idsn = subflow_req->idsn; /* this is the first subflow, id is always 0 */ new_ctx->local_id_valid = 1; } else if (subflow_req->mp_join) { new_ctx->ssn_offset = subflow_req->ssn_offset; new_ctx->mp_join = 1; new_ctx->fully_established = 1; new_ctx->remote_key_valid = 1; new_ctx->backup = subflow_req->backup; new_ctx->remote_id = subflow_req->remote_id; new_ctx->token = subflow_req->token; new_ctx->thmac = subflow_req->thmac; /* the subflow req id is valid, fetched via subflow_check_req() * and subflow_token_join_request() */ subflow_set_local_id(new_ctx, subflow_req->local_id); } } static void tcp_release_cb_override(struct sock *ssk) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); long status; /* process and clear all the pending actions, but leave the subflow into * the napi queue. To respect locking, only the same CPU that originated * the action can touch the list. mptcp_napi_poll will take care of it. */ status = set_mask_bits(&subflow->delegated_status, MPTCP_DELEGATE_ACTIONS_MASK, 0); if (status) mptcp_subflow_process_delegated(ssk, status); tcp_release_cb(ssk); } static int tcp_abort_override(struct sock *ssk, int err) { /* closing a listener subflow requires a great deal of care. * keep it simple and just prevent such operation */ if (inet_sk_state_load(ssk) == TCP_LISTEN) return -EINVAL; return tcp_abort(ssk, err); } static struct tcp_ulp_ops subflow_ulp_ops __read_mostly = { .name = "mptcp", .owner = THIS_MODULE, .init = subflow_ulp_init, .release = subflow_ulp_release, .clone = subflow_ulp_clone, }; static int subflow_ops_init(struct request_sock_ops *subflow_ops) { subflow_ops->obj_size = sizeof(struct mptcp_subflow_request_sock); subflow_ops->slab = kmem_cache_create(subflow_ops->slab_name, subflow_ops->obj_size, 0, SLAB_ACCOUNT | SLAB_TYPESAFE_BY_RCU, NULL); if (!subflow_ops->slab) return -ENOMEM; return 0; } void __init mptcp_subflow_init(void) { mptcp_subflow_v4_request_sock_ops = tcp_request_sock_ops; mptcp_subflow_v4_request_sock_ops.slab_name = "request_sock_subflow_v4"; mptcp_subflow_v4_request_sock_ops.destructor = subflow_v4_req_destructor; if (subflow_ops_init(&mptcp_subflow_v4_request_sock_ops) != 0) panic("MPTCP: failed to init subflow v4 request sock ops\n"); subflow_request_sock_ipv4_ops = tcp_request_sock_ipv4_ops; subflow_request_sock_ipv4_ops.route_req = subflow_v4_route_req; subflow_request_sock_ipv4_ops.send_synack = subflow_v4_send_synack; subflow_specific = ipv4_specific; subflow_specific.conn_request = subflow_v4_conn_request; subflow_specific.syn_recv_sock = subflow_syn_recv_sock; subflow_specific.sk_rx_dst_set = subflow_finish_connect; subflow_specific.rebuild_header = subflow_rebuild_header; tcp_prot_override = tcp_prot; tcp_prot_override.release_cb = tcp_release_cb_override; tcp_prot_override.diag_destroy = tcp_abort_override; #if IS_ENABLED(CONFIG_MPTCP_IPV6) /* In struct mptcp_subflow_request_sock, we assume the TCP request sock * structures for v4 and v6 have the same size. It should not changed in * the future but better to make sure to be warned if it is no longer * the case. */ BUILD_BUG_ON(sizeof(struct tcp_request_sock) != sizeof(struct tcp6_request_sock)); mptcp_subflow_v6_request_sock_ops = tcp6_request_sock_ops; mptcp_subflow_v6_request_sock_ops.slab_name = "request_sock_subflow_v6"; mptcp_subflow_v6_request_sock_ops.destructor = subflow_v6_req_destructor; if (subflow_ops_init(&mptcp_subflow_v6_request_sock_ops) != 0) panic("MPTCP: failed to init subflow v6 request sock ops\n"); subflow_request_sock_ipv6_ops = tcp_request_sock_ipv6_ops; subflow_request_sock_ipv6_ops.route_req = subflow_v6_route_req; subflow_request_sock_ipv6_ops.send_synack = subflow_v6_send_synack; subflow_v6_specific = ipv6_specific; subflow_v6_specific.conn_request = subflow_v6_conn_request; subflow_v6_specific.syn_recv_sock = subflow_syn_recv_sock; subflow_v6_specific.sk_rx_dst_set = subflow_finish_connect; subflow_v6_specific.rebuild_header = subflow_v6_rebuild_header; subflow_v6m_specific = subflow_v6_specific; subflow_v6m_specific.queue_xmit = ipv4_specific.queue_xmit; subflow_v6m_specific.send_check = ipv4_specific.send_check; subflow_v6m_specific.net_header_len = ipv4_specific.net_header_len; subflow_v6m_specific.mtu_reduced = ipv4_specific.mtu_reduced; subflow_v6m_specific.rebuild_header = subflow_rebuild_header; tcpv6_prot_override = tcpv6_prot; tcpv6_prot_override.release_cb = tcp_release_cb_override; tcpv6_prot_override.diag_destroy = tcp_abort_override; #endif mptcp_diag_subflow_init(&subflow_ulp_ops); if (tcp_register_ulp(&subflow_ulp_ops) != 0) panic("MPTCP: failed to register subflows to ULP\n"); }
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