// SPDX-License-Identifier: GPL-2.0 /* Multipath TCP * * Copyright (c) 2017 - 2019, Intel Corporation. */ #define pr_fmt(fmt) "MPTCP: " fmt #include #include #include #include #include #include #include #include #include #include #include #if IS_ENABLED(CONFIG_MPTCP_IPV6) #include #endif #include #include #include "protocol.h" #include "mib.h" #define CREATE_TRACE_POINTS #include #if IS_ENABLED(CONFIG_MPTCP_IPV6) struct mptcp6_sock { struct mptcp_sock msk; struct ipv6_pinfo np; }; #endif struct mptcp_skb_cb { u64 map_seq; u64 end_seq; u32 offset; u8 has_rxtstamp:1; }; #define MPTCP_SKB_CB(__skb) ((struct mptcp_skb_cb *)&((__skb)->cb[0])) enum { MPTCP_CMSG_TS = BIT(0), }; static struct percpu_counter mptcp_sockets_allocated; static void __mptcp_destroy_sock(struct sock *sk); static void __mptcp_check_send_data_fin(struct sock *sk); DEFINE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions); static struct net_device mptcp_napi_dev; /* If msk has an initial subflow socket, and the MP_CAPABLE handshake has not * completed yet or has failed, return the subflow socket. * Otherwise return NULL. */ struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk) { if (!msk->subflow || READ_ONCE(msk->can_ack)) return NULL; return msk->subflow; } /* Returns end sequence number of the receiver's advertised window */ static u64 mptcp_wnd_end(const struct mptcp_sock *msk) { return READ_ONCE(msk->wnd_end); } static bool mptcp_is_tcpsk(struct sock *sk) { struct socket *sock = sk->sk_socket; if (unlikely(sk->sk_prot == &tcp_prot)) { /* we are being invoked after mptcp_accept() has * accepted a non-mp-capable flow: sk is a tcp_sk, * not an mptcp one. * * Hand the socket over to tcp so all further socket ops * bypass mptcp. */ sock->ops = &inet_stream_ops; return true; #if IS_ENABLED(CONFIG_MPTCP_IPV6) } else if (unlikely(sk->sk_prot == &tcpv6_prot)) { sock->ops = &inet6_stream_ops; return true; #endif } return false; } static int __mptcp_socket_create(struct mptcp_sock *msk) { struct mptcp_subflow_context *subflow; struct sock *sk = (struct sock *)msk; struct socket *ssock; int err; err = mptcp_subflow_create_socket(sk, &ssock); if (err) return err; msk->first = ssock->sk; msk->subflow = ssock; subflow = mptcp_subflow_ctx(ssock->sk); list_add(&subflow->node, &msk->conn_list); sock_hold(ssock->sk); subflow->request_mptcp = 1; mptcp_sock_graft(msk->first, sk->sk_socket); return 0; } static void mptcp_drop(struct sock *sk, struct sk_buff *skb) { sk_drops_add(sk, skb); __kfree_skb(skb); } static void mptcp_rmem_charge(struct sock *sk, int size) { mptcp_sk(sk)->rmem_fwd_alloc -= size; } static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to, struct sk_buff *from) { bool fragstolen; int delta; if (MPTCP_SKB_CB(from)->offset || !skb_try_coalesce(to, from, &fragstolen, &delta)) return false; pr_debug("colesced seq %llx into %llx new len %d new end seq %llx", MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq, to->len, MPTCP_SKB_CB(from)->end_seq); MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq; kfree_skb_partial(from, fragstolen); atomic_add(delta, &sk->sk_rmem_alloc); mptcp_rmem_charge(sk, delta); return true; } static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to, struct sk_buff *from) { if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq) return false; return mptcp_try_coalesce((struct sock *)msk, to, from); } static void __mptcp_rmem_reclaim(struct sock *sk, int amount) { amount >>= SK_MEM_QUANTUM_SHIFT; mptcp_sk(sk)->rmem_fwd_alloc -= amount << SK_MEM_QUANTUM_SHIFT; __sk_mem_reduce_allocated(sk, amount); } static void mptcp_rmem_uncharge(struct sock *sk, int size) { struct mptcp_sock *msk = mptcp_sk(sk); int reclaimable; msk->rmem_fwd_alloc += size; reclaimable = msk->rmem_fwd_alloc - sk_unused_reserved_mem(sk); /* see sk_mem_uncharge() for the rationale behind the following schema */ if (unlikely(reclaimable >= SK_RECLAIM_THRESHOLD)) __mptcp_rmem_reclaim(sk, SK_RECLAIM_CHUNK); } static void mptcp_rfree(struct sk_buff *skb) { unsigned int len = skb->truesize; struct sock *sk = skb->sk; atomic_sub(len, &sk->sk_rmem_alloc); mptcp_rmem_uncharge(sk, len); } static void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk) { skb_orphan(skb); skb->sk = sk; skb->destructor = mptcp_rfree; atomic_add(skb->truesize, &sk->sk_rmem_alloc); mptcp_rmem_charge(sk, skb->truesize); } /* "inspired" by tcp_data_queue_ofo(), main differences: * - use mptcp seqs * - don't cope with sacks */ static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb) { struct sock *sk = (struct sock *)msk; struct rb_node **p, *parent; u64 seq, end_seq, max_seq; struct sk_buff *skb1; seq = MPTCP_SKB_CB(skb)->map_seq; end_seq = MPTCP_SKB_CB(skb)->end_seq; max_seq = READ_ONCE(msk->rcv_wnd_sent); pr_debug("msk=%p seq=%llx limit=%llx empty=%d", msk, seq, max_seq, RB_EMPTY_ROOT(&msk->out_of_order_queue)); if (after64(end_seq, max_seq)) { /* out of window */ mptcp_drop(sk, skb); pr_debug("oow by %lld, rcv_wnd_sent %llu\n", (unsigned long long)end_seq - (unsigned long)max_seq, (unsigned long long)msk->rcv_wnd_sent); MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW); return; } p = &msk->out_of_order_queue.rb_node; MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE); if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) { rb_link_node(&skb->rbnode, NULL, p); rb_insert_color(&skb->rbnode, &msk->out_of_order_queue); msk->ooo_last_skb = skb; goto end; } /* with 2 subflows, adding at end of ooo queue is quite likely * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup. */ if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) { MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE); MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL); return; } /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */ if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) { MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL); parent = &msk->ooo_last_skb->rbnode; p = &parent->rb_right; goto insert; } /* Find place to insert this segment. Handle overlaps on the way. */ parent = NULL; while (*p) { parent = *p; skb1 = rb_to_skb(parent); if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) { p = &parent->rb_left; continue; } if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) { if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) { /* All the bits are present. Drop. */ mptcp_drop(sk, skb); MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); return; } if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) { /* partial overlap: * | skb | * | skb1 | * continue traversing */ } else { /* skb's seq == skb1's seq and skb covers skb1. * Replace skb1 with skb. */ rb_replace_node(&skb1->rbnode, &skb->rbnode, &msk->out_of_order_queue); mptcp_drop(sk, skb1); MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); goto merge_right; } } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) { MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE); return; } p = &parent->rb_right; } insert: /* Insert segment into RB tree. */ rb_link_node(&skb->rbnode, parent, p); rb_insert_color(&skb->rbnode, &msk->out_of_order_queue); merge_right: /* Remove other segments covered by skb. */ while ((skb1 = skb_rb_next(skb)) != NULL) { if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) break; rb_erase(&skb1->rbnode, &msk->out_of_order_queue); mptcp_drop(sk, skb1); MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); } /* If there is no skb after us, we are the last_skb ! */ if (!skb1) msk->ooo_last_skb = skb; end: skb_condense(skb); mptcp_set_owner_r(skb, sk); } static bool mptcp_rmem_schedule(struct sock *sk, struct sock *ssk, int size) { struct mptcp_sock *msk = mptcp_sk(sk); int amt, amount; if (size < msk->rmem_fwd_alloc) return true; amt = sk_mem_pages(size); amount = amt << SK_MEM_QUANTUM_SHIFT; msk->rmem_fwd_alloc += amount; if (!__sk_mem_raise_allocated(sk, size, amt, SK_MEM_RECV)) { if (ssk->sk_forward_alloc < amount) { msk->rmem_fwd_alloc -= amount; return false; } ssk->sk_forward_alloc -= amount; } return true; } static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk, struct sk_buff *skb, unsigned int offset, size_t copy_len) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); struct sock *sk = (struct sock *)msk; struct sk_buff *tail; bool has_rxtstamp; __skb_unlink(skb, &ssk->sk_receive_queue); skb_ext_reset(skb); skb_orphan(skb); /* try to fetch required memory from subflow */ if (!mptcp_rmem_schedule(sk, ssk, skb->truesize)) goto drop; has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp; /* the skb map_seq accounts for the skb offset: * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq * value */ MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow); MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len; MPTCP_SKB_CB(skb)->offset = offset; MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp; if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) { /* in sequence */ WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len); tail = skb_peek_tail(&sk->sk_receive_queue); if (tail && mptcp_try_coalesce(sk, tail, skb)) return true; mptcp_set_owner_r(skb, sk); __skb_queue_tail(&sk->sk_receive_queue, skb); return true; } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) { mptcp_data_queue_ofo(msk, skb); return false; } /* old data, keep it simple and drop the whole pkt, sender * will retransmit as needed, if needed. */ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); drop: mptcp_drop(sk, skb); return false; } static void mptcp_stop_timer(struct sock *sk) { struct inet_connection_sock *icsk = inet_csk(sk); sk_stop_timer(sk, &icsk->icsk_retransmit_timer); mptcp_sk(sk)->timer_ival = 0; } static void mptcp_close_wake_up(struct sock *sk) { if (sock_flag(sk, SOCK_DEAD)) return; sk->sk_state_change(sk); if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == TCP_CLOSE) sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); else sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN); } static bool mptcp_pending_data_fin_ack(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); return !__mptcp_check_fallback(msk) && ((1 << sk->sk_state) & (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) && msk->write_seq == READ_ONCE(msk->snd_una); } static void mptcp_check_data_fin_ack(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); /* Look for an acknowledged DATA_FIN */ if (mptcp_pending_data_fin_ack(sk)) { WRITE_ONCE(msk->snd_data_fin_enable, 0); switch (sk->sk_state) { case TCP_FIN_WAIT1: inet_sk_state_store(sk, TCP_FIN_WAIT2); break; case TCP_CLOSING: case TCP_LAST_ACK: inet_sk_state_store(sk, TCP_CLOSE); break; } mptcp_close_wake_up(sk); } } static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq) { struct mptcp_sock *msk = mptcp_sk(sk); if (READ_ONCE(msk->rcv_data_fin) && ((1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) { u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq); if (msk->ack_seq == rcv_data_fin_seq) { if (seq) *seq = rcv_data_fin_seq; return true; } } return false; } static void mptcp_set_datafin_timeout(const struct sock *sk) { struct inet_connection_sock *icsk = inet_csk(sk); mptcp_sk(sk)->timer_ival = min(TCP_RTO_MAX, TCP_RTO_MIN << icsk->icsk_retransmits); } static void __mptcp_set_timeout(struct sock *sk, long tout) { mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN; } static long mptcp_timeout_from_subflow(const struct mptcp_subflow_context *subflow) { const struct sock *ssk = mptcp_subflow_tcp_sock(subflow); return inet_csk(ssk)->icsk_pending && !subflow->stale_count ? inet_csk(ssk)->icsk_timeout - jiffies : 0; } static void mptcp_set_timeout(struct sock *sk) { struct mptcp_subflow_context *subflow; long tout = 0; mptcp_for_each_subflow(mptcp_sk(sk), subflow) tout = max(tout, mptcp_timeout_from_subflow(subflow)); __mptcp_set_timeout(sk, tout); } static bool tcp_can_send_ack(const struct sock *ssk) { return !((1 << inet_sk_state_load(ssk)) & (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN)); } void mptcp_subflow_send_ack(struct sock *ssk) { bool slow; slow = lock_sock_fast(ssk); if (tcp_can_send_ack(ssk)) tcp_send_ack(ssk); unlock_sock_fast(ssk, slow); } static void mptcp_send_ack(struct mptcp_sock *msk) { struct mptcp_subflow_context *subflow; mptcp_for_each_subflow(msk, subflow) mptcp_subflow_send_ack(mptcp_subflow_tcp_sock(subflow)); } static void mptcp_subflow_cleanup_rbuf(struct sock *ssk) { bool slow; slow = lock_sock_fast(ssk); if (tcp_can_send_ack(ssk)) tcp_cleanup_rbuf(ssk, 1); unlock_sock_fast(ssk, slow); } static bool mptcp_subflow_could_cleanup(const struct sock *ssk, bool rx_empty) { const struct inet_connection_sock *icsk = inet_csk(ssk); u8 ack_pending = READ_ONCE(icsk->icsk_ack.pending); const struct tcp_sock *tp = tcp_sk(ssk); return (ack_pending & ICSK_ACK_SCHED) && ((READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->rcv_wup) > READ_ONCE(icsk->icsk_ack.rcv_mss)) || (rx_empty && ack_pending & (ICSK_ACK_PUSHED2 | ICSK_ACK_PUSHED))); } static void mptcp_cleanup_rbuf(struct mptcp_sock *msk) { int old_space = READ_ONCE(msk->old_wspace); struct mptcp_subflow_context *subflow; struct sock *sk = (struct sock *)msk; int space = __mptcp_space(sk); bool cleanup, rx_empty; cleanup = (space > 0) && (space >= (old_space << 1)); rx_empty = !__mptcp_rmem(sk); mptcp_for_each_subflow(msk, subflow) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); if (cleanup || mptcp_subflow_could_cleanup(ssk, rx_empty)) mptcp_subflow_cleanup_rbuf(ssk); } } static bool mptcp_check_data_fin(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); u64 rcv_data_fin_seq; bool ret = false; if (__mptcp_check_fallback(msk)) return ret; /* Need to ack a DATA_FIN received from a peer while this side * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2. * msk->rcv_data_fin was set when parsing the incoming options * at the subflow level and the msk lock was not held, so this * is the first opportunity to act on the DATA_FIN and change * the msk state. * * If we are caught up to the sequence number of the incoming * DATA_FIN, send the DATA_ACK now and do state transition. If * not caught up, do nothing and let the recv code send DATA_ACK * when catching up. */ if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) { WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1); WRITE_ONCE(msk->rcv_data_fin, 0); sk->sk_shutdown |= RCV_SHUTDOWN; smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ switch (sk->sk_state) { case TCP_ESTABLISHED: inet_sk_state_store(sk, TCP_CLOSE_WAIT); break; case TCP_FIN_WAIT1: inet_sk_state_store(sk, TCP_CLOSING); break; case TCP_FIN_WAIT2: inet_sk_state_store(sk, TCP_CLOSE); break; default: /* Other states not expected */ WARN_ON_ONCE(1); break; } ret = true; mptcp_send_ack(msk); mptcp_close_wake_up(sk); } return ret; } static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk, struct sock *ssk, unsigned int *bytes) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); struct sock *sk = (struct sock *)msk; unsigned int moved = 0; bool more_data_avail; struct tcp_sock *tp; bool done = false; int sk_rbuf; sk_rbuf = READ_ONCE(sk->sk_rcvbuf); if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { int ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf); if (unlikely(ssk_rbuf > sk_rbuf)) { WRITE_ONCE(sk->sk_rcvbuf, ssk_rbuf); sk_rbuf = ssk_rbuf; } } pr_debug("msk=%p ssk=%p", msk, ssk); tp = tcp_sk(ssk); do { u32 map_remaining, offset; u32 seq = tp->copied_seq; struct sk_buff *skb; bool fin; /* try to move as much data as available */ map_remaining = subflow->map_data_len - mptcp_subflow_get_map_offset(subflow); skb = skb_peek(&ssk->sk_receive_queue); if (!skb) { /* if no data is found, a racing workqueue/recvmsg * already processed the new data, stop here or we * can enter an infinite loop */ if (!moved) done = true; break; } if (__mptcp_check_fallback(msk)) { /* if we are running under the workqueue, TCP could have * collapsed skbs between dummy map creation and now * be sure to adjust the size */ map_remaining = skb->len; subflow->map_data_len = skb->len; } offset = seq - TCP_SKB_CB(skb)->seq; fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN; if (fin) { done = true; seq++; } if (offset < skb->len) { size_t len = skb->len - offset; if (tp->urg_data) done = true; if (__mptcp_move_skb(msk, ssk, skb, offset, len)) moved += len; seq += len; if (WARN_ON_ONCE(map_remaining < len)) break; } else { WARN_ON_ONCE(!fin); sk_eat_skb(ssk, skb); done = true; } WRITE_ONCE(tp->copied_seq, seq); more_data_avail = mptcp_subflow_data_available(ssk); if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf) { done = true; break; } } while (more_data_avail); *bytes += moved; return done; } static bool __mptcp_ofo_queue(struct mptcp_sock *msk) { struct sock *sk = (struct sock *)msk; struct sk_buff *skb, *tail; bool moved = false; struct rb_node *p; u64 end_seq; p = rb_first(&msk->out_of_order_queue); pr_debug("msk=%p empty=%d", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue)); while (p) { skb = rb_to_skb(p); if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) break; p = rb_next(p); rb_erase(&skb->rbnode, &msk->out_of_order_queue); if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq, msk->ack_seq))) { mptcp_drop(sk, skb); MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); continue; } end_seq = MPTCP_SKB_CB(skb)->end_seq; tail = skb_peek_tail(&sk->sk_receive_queue); if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) { int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq; /* skip overlapping data, if any */ pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d", MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq, delta); MPTCP_SKB_CB(skb)->offset += delta; __skb_queue_tail(&sk->sk_receive_queue, skb); } msk->ack_seq = end_seq; moved = true; } return moved; } /* In most cases we will be able to lock the mptcp socket. If its already * owned, we need to defer to the work queue to avoid ABBA deadlock. */ static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk) { struct sock *sk = (struct sock *)msk; unsigned int moved = 0; __mptcp_move_skbs_from_subflow(msk, ssk, &moved); __mptcp_ofo_queue(msk); if (unlikely(ssk->sk_err)) { if (!sock_owned_by_user(sk)) __mptcp_error_report(sk); else set_bit(MPTCP_ERROR_REPORT, &msk->flags); } /* If the moves have caught up with the DATA_FIN sequence number * it's time to ack the DATA_FIN and change socket state, but * this is not a good place to change state. Let the workqueue * do it. */ if (mptcp_pending_data_fin(sk, NULL)) mptcp_schedule_work(sk); return moved > 0; } void mptcp_data_ready(struct sock *sk, struct sock *ssk) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); struct mptcp_sock *msk = mptcp_sk(sk); int sk_rbuf, ssk_rbuf; /* The peer can send data while we are shutting down this * subflow at msk destruction time, but we must avoid enqueuing * more data to the msk receive queue */ if (unlikely(subflow->disposable)) return; ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf); sk_rbuf = READ_ONCE(sk->sk_rcvbuf); if (unlikely(ssk_rbuf > sk_rbuf)) sk_rbuf = ssk_rbuf; /* over limit? can't append more skbs to msk, Also, no need to wake-up*/ if (__mptcp_rmem(sk) > sk_rbuf) { MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED); return; } /* Wake-up the reader only for in-sequence data */ mptcp_data_lock(sk); if (move_skbs_to_msk(msk, ssk)) sk->sk_data_ready(sk); mptcp_data_unlock(sk); } static bool mptcp_do_flush_join_list(struct mptcp_sock *msk) { struct mptcp_subflow_context *subflow; bool ret = false; if (likely(list_empty(&msk->join_list))) return false; spin_lock_bh(&msk->join_list_lock); list_for_each_entry(subflow, &msk->join_list, node) { u32 sseq = READ_ONCE(subflow->setsockopt_seq); mptcp_propagate_sndbuf((struct sock *)msk, mptcp_subflow_tcp_sock(subflow)); if (READ_ONCE(msk->setsockopt_seq) != sseq) ret = true; } list_splice_tail_init(&msk->join_list, &msk->conn_list); spin_unlock_bh(&msk->join_list_lock); return ret; } void __mptcp_flush_join_list(struct mptcp_sock *msk) { if (likely(!mptcp_do_flush_join_list(msk))) return; if (!test_and_set_bit(MPTCP_WORK_SYNC_SETSOCKOPT, &msk->flags)) mptcp_schedule_work((struct sock *)msk); } static void mptcp_flush_join_list(struct mptcp_sock *msk) { bool sync_needed = test_and_clear_bit(MPTCP_WORK_SYNC_SETSOCKOPT, &msk->flags); might_sleep(); if (!mptcp_do_flush_join_list(msk) && !sync_needed) return; mptcp_sockopt_sync_all(msk); } static bool mptcp_timer_pending(struct sock *sk) { return timer_pending(&inet_csk(sk)->icsk_retransmit_timer); } static void mptcp_reset_timer(struct sock *sk) { struct inet_connection_sock *icsk = inet_csk(sk); unsigned long tout; /* prevent rescheduling on close */ if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE)) return; tout = mptcp_sk(sk)->timer_ival; sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout); } bool mptcp_schedule_work(struct sock *sk) { if (inet_sk_state_load(sk) != TCP_CLOSE && schedule_work(&mptcp_sk(sk)->work)) { /* each subflow already holds a reference to the sk, and the * workqueue is invoked by a subflow, so sk can't go away here. */ sock_hold(sk); return true; } return false; } void mptcp_subflow_eof(struct sock *sk) { if (!test_and_set_bit(MPTCP_WORK_EOF, &mptcp_sk(sk)->flags)) mptcp_schedule_work(sk); } static void mptcp_check_for_eof(struct mptcp_sock *msk) { struct mptcp_subflow_context *subflow; struct sock *sk = (struct sock *)msk; int receivers = 0; mptcp_for_each_subflow(msk, subflow) receivers += !subflow->rx_eof; if (receivers) return; if (!(sk->sk_shutdown & RCV_SHUTDOWN)) { /* hopefully temporary hack: propagate shutdown status * to msk, when all subflows agree on it */ sk->sk_shutdown |= RCV_SHUTDOWN; smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ sk->sk_data_ready(sk); } switch (sk->sk_state) { case TCP_ESTABLISHED: inet_sk_state_store(sk, TCP_CLOSE_WAIT); break; case TCP_FIN_WAIT1: inet_sk_state_store(sk, TCP_CLOSING); break; case TCP_FIN_WAIT2: inet_sk_state_store(sk, TCP_CLOSE); break; default: return; } mptcp_close_wake_up(sk); } static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk) { struct mptcp_subflow_context *subflow; struct sock *sk = (struct sock *)msk; sock_owned_by_me(sk); mptcp_for_each_subflow(msk, subflow) { if (READ_ONCE(subflow->data_avail)) return mptcp_subflow_tcp_sock(subflow); } return NULL; } static bool mptcp_skb_can_collapse_to(u64 write_seq, const struct sk_buff *skb, const struct mptcp_ext *mpext) { if (!tcp_skb_can_collapse_to(skb)) return false; /* can collapse only if MPTCP level sequence is in order and this * mapping has not been xmitted yet */ return mpext && mpext->data_seq + mpext->data_len == write_seq && !mpext->frozen; } /* we can append data to the given data frag if: * - there is space available in the backing page_frag * - the data frag tail matches the current page_frag free offset * - the data frag end sequence number matches the current write seq */ static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk, const struct page_frag *pfrag, const struct mptcp_data_frag *df) { return df && pfrag->page == df->page && pfrag->size - pfrag->offset > 0 && pfrag->offset == (df->offset + df->data_len) && df->data_seq + df->data_len == msk->write_seq; } static void __mptcp_mem_reclaim_partial(struct sock *sk) { int reclaimable = mptcp_sk(sk)->rmem_fwd_alloc - sk_unused_reserved_mem(sk); lockdep_assert_held_once(&sk->sk_lock.slock); __mptcp_rmem_reclaim(sk, reclaimable - 1); sk_mem_reclaim_partial(sk); } static void mptcp_mem_reclaim_partial(struct sock *sk) { mptcp_data_lock(sk); __mptcp_mem_reclaim_partial(sk); mptcp_data_unlock(sk); } static void dfrag_uncharge(struct sock *sk, int len) { sk_mem_uncharge(sk, len); sk_wmem_queued_add(sk, -len); } static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag) { int len = dfrag->data_len + dfrag->overhead; list_del(&dfrag->list); dfrag_uncharge(sk, len); put_page(dfrag->page); } static void __mptcp_clean_una(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); struct mptcp_data_frag *dtmp, *dfrag; bool cleaned = false; u64 snd_una; /* on fallback we just need to ignore snd_una, as this is really * plain TCP */ if (__mptcp_check_fallback(msk)) msk->snd_una = READ_ONCE(msk->snd_nxt); snd_una = msk->snd_una; list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) { if (after64(dfrag->data_seq + dfrag->data_len, snd_una)) break; if (unlikely(dfrag == msk->first_pending)) { /* in recovery mode can see ack after the current snd head */ if (WARN_ON_ONCE(!msk->recovery)) break; WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); } dfrag_clear(sk, dfrag); cleaned = true; } dfrag = mptcp_rtx_head(sk); if (dfrag && after64(snd_una, dfrag->data_seq)) { u64 delta = snd_una - dfrag->data_seq; /* prevent wrap around in recovery mode */ if (unlikely(delta > dfrag->already_sent)) { if (WARN_ON_ONCE(!msk->recovery)) goto out; if (WARN_ON_ONCE(delta > dfrag->data_len)) goto out; dfrag->already_sent += delta - dfrag->already_sent; } dfrag->data_seq += delta; dfrag->offset += delta; dfrag->data_len -= delta; dfrag->already_sent -= delta; dfrag_uncharge(sk, delta); cleaned = true; } /* all retransmitted data acked, recovery completed */ if (unlikely(msk->recovery) && after64(msk->snd_una, msk->recovery_snd_nxt)) msk->recovery = false; out: if (cleaned && tcp_under_memory_pressure(sk)) __mptcp_mem_reclaim_partial(sk); if (snd_una == READ_ONCE(msk->snd_nxt) && snd_una == READ_ONCE(msk->write_seq)) { if (mptcp_timer_pending(sk) && !mptcp_data_fin_enabled(msk)) mptcp_stop_timer(sk); } else { mptcp_reset_timer(sk); } } static void __mptcp_clean_una_wakeup(struct sock *sk) { lockdep_assert_held_once(&sk->sk_lock.slock); __mptcp_clean_una(sk); mptcp_write_space(sk); } static void mptcp_clean_una_wakeup(struct sock *sk) { mptcp_data_lock(sk); __mptcp_clean_una_wakeup(sk); mptcp_data_unlock(sk); } static void mptcp_enter_memory_pressure(struct sock *sk) { struct mptcp_subflow_context *subflow; struct mptcp_sock *msk = mptcp_sk(sk); bool first = true; sk_stream_moderate_sndbuf(sk); mptcp_for_each_subflow(msk, subflow) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); if (first) tcp_enter_memory_pressure(ssk); sk_stream_moderate_sndbuf(ssk); first = false; } } /* ensure we get enough memory for the frag hdr, beyond some minimal amount of * data */ static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag) { if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag), pfrag, sk->sk_allocation))) return true; mptcp_enter_memory_pressure(sk); return false; } static struct mptcp_data_frag * mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag, int orig_offset) { int offset = ALIGN(orig_offset, sizeof(long)); struct mptcp_data_frag *dfrag; dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset); dfrag->data_len = 0; dfrag->data_seq = msk->write_seq; dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag); dfrag->offset = offset + sizeof(struct mptcp_data_frag); dfrag->already_sent = 0; dfrag->page = pfrag->page; return dfrag; } struct mptcp_sendmsg_info { int mss_now; int size_goal; u16 limit; u16 sent; unsigned int flags; bool data_lock_held; }; static int mptcp_check_allowed_size(struct mptcp_sock *msk, u64 data_seq, int avail_size) { u64 window_end = mptcp_wnd_end(msk); if (__mptcp_check_fallback(msk)) return avail_size; if (!before64(data_seq + avail_size, window_end)) { u64 allowed_size = window_end - data_seq; return min_t(unsigned int, allowed_size, avail_size); } return avail_size; } static bool __mptcp_add_ext(struct sk_buff *skb, gfp_t gfp) { struct skb_ext *mpext = __skb_ext_alloc(gfp); if (!mpext) return false; __skb_ext_set(skb, SKB_EXT_MPTCP, mpext); return true; } static struct sk_buff *__mptcp_do_alloc_tx_skb(struct sock *sk, gfp_t gfp) { struct sk_buff *skb; skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp); if (likely(skb)) { if (likely(__mptcp_add_ext(skb, gfp))) { skb_reserve(skb, MAX_TCP_HEADER); skb->ip_summed = CHECKSUM_PARTIAL; INIT_LIST_HEAD(&skb->tcp_tsorted_anchor); return skb; } __kfree_skb(skb); } else { mptcp_enter_memory_pressure(sk); } return NULL; } static struct sk_buff *__mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp) { struct sk_buff *skb; skb = __mptcp_do_alloc_tx_skb(sk, gfp); if (!skb) return NULL; if (likely(sk_wmem_schedule(ssk, skb->truesize))) { tcp_skb_entail(ssk, skb); return skb; } kfree_skb(skb); return NULL; } static struct sk_buff *mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, bool data_lock_held) { gfp_t gfp = data_lock_held ? GFP_ATOMIC : sk->sk_allocation; if (unlikely(tcp_under_memory_pressure(sk))) { if (data_lock_held) __mptcp_mem_reclaim_partial(sk); else mptcp_mem_reclaim_partial(sk); } return __mptcp_alloc_tx_skb(sk, ssk, gfp); } /* note: this always recompute the csum on the whole skb, even * if we just appended a single frag. More status info needed */ static void mptcp_update_data_checksum(struct sk_buff *skb, int added) { struct mptcp_ext *mpext = mptcp_get_ext(skb); __wsum csum = ~csum_unfold(mpext->csum); int offset = skb->len - added; mpext->csum = csum_fold(csum_block_add(csum, skb_checksum(skb, offset, added, 0), offset)); } static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, struct mptcp_data_frag *dfrag, struct mptcp_sendmsg_info *info) { u64 data_seq = dfrag->data_seq + info->sent; int offset = dfrag->offset + info->sent; struct mptcp_sock *msk = mptcp_sk(sk); bool zero_window_probe = false; struct mptcp_ext *mpext = NULL; bool can_coalesce = false; bool reuse_skb = true; struct sk_buff *skb; size_t copy; int i; pr_debug("msk=%p ssk=%p sending dfrag at seq=%llu len=%u already sent=%u", msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent); if (WARN_ON_ONCE(info->sent > info->limit || info->limit > dfrag->data_len)) return 0; /* compute send limit */ info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags); copy = info->size_goal; skb = tcp_write_queue_tail(ssk); if (skb && copy > skb->len) { /* Limit the write to the size available in the * current skb, if any, so that we create at most a new skb. * Explicitly tells TCP internals to avoid collapsing on later * queue management operation, to avoid breaking the ext <-> * SSN association set here */ mpext = skb_ext_find(skb, SKB_EXT_MPTCP); if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) { TCP_SKB_CB(skb)->eor = 1; goto alloc_skb; } i = skb_shinfo(skb)->nr_frags; can_coalesce = skb_can_coalesce(skb, i, dfrag->page, offset); if (!can_coalesce && i >= sysctl_max_skb_frags) { tcp_mark_push(tcp_sk(ssk), skb); goto alloc_skb; } copy -= skb->len; } else { alloc_skb: skb = mptcp_alloc_tx_skb(sk, ssk, info->data_lock_held); if (!skb) return -ENOMEM; i = skb_shinfo(skb)->nr_frags; reuse_skb = false; mpext = skb_ext_find(skb, SKB_EXT_MPTCP); } /* Zero window and all data acked? Probe. */ copy = mptcp_check_allowed_size(msk, data_seq, copy); if (copy == 0) { u64 snd_una = READ_ONCE(msk->snd_una); if (snd_una != msk->snd_nxt) { tcp_remove_empty_skb(ssk); return 0; } zero_window_probe = true; data_seq = snd_una - 1; copy = 1; /* all mptcp-level data is acked, no skbs should be present into the * ssk write queue */ WARN_ON_ONCE(reuse_skb); } copy = min_t(size_t, copy, info->limit - info->sent); if (!sk_wmem_schedule(ssk, copy)) { tcp_remove_empty_skb(ssk); return -ENOMEM; } if (can_coalesce) { skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); } else { get_page(dfrag->page); skb_fill_page_desc(skb, i, dfrag->page, offset, copy); } skb->len += copy; skb->data_len += copy; skb->truesize += copy; sk_wmem_queued_add(ssk, copy); sk_mem_charge(ssk, copy); WRITE_ONCE(tcp_sk(ssk)->write_seq, tcp_sk(ssk)->write_seq + copy); TCP_SKB_CB(skb)->end_seq += copy; tcp_skb_pcount_set(skb, 0); /* on skb reuse we just need to update the DSS len */ if (reuse_skb) { TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; mpext->data_len += copy; WARN_ON_ONCE(zero_window_probe); goto out; } memset(mpext, 0, sizeof(*mpext)); mpext->data_seq = data_seq; mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq; mpext->data_len = copy; mpext->use_map = 1; mpext->dsn64 = 1; pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d", mpext->data_seq, mpext->subflow_seq, mpext->data_len, mpext->dsn64); if (zero_window_probe) { mptcp_subflow_ctx(ssk)->rel_write_seq += copy; mpext->frozen = 1; if (READ_ONCE(msk->csum_enabled)) mptcp_update_data_checksum(skb, copy); tcp_push_pending_frames(ssk); return 0; } out: if (READ_ONCE(msk->csum_enabled)) mptcp_update_data_checksum(skb, copy); mptcp_subflow_ctx(ssk)->rel_write_seq += copy; return copy; } #define MPTCP_SEND_BURST_SIZE ((1 << 16) - \ sizeof(struct tcphdr) - \ MAX_TCP_OPTION_SPACE - \ sizeof(struct ipv6hdr) - \ sizeof(struct frag_hdr)) struct subflow_send_info { struct sock *ssk; u64 ratio; }; void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow) { if (!subflow->stale) return; subflow->stale = 0; MPTCP_INC_STATS(sock_net(mptcp_subflow_tcp_sock(subflow)), MPTCP_MIB_SUBFLOWRECOVER); } bool mptcp_subflow_active(struct mptcp_subflow_context *subflow) { if (unlikely(subflow->stale)) { u32 rcv_tstamp = READ_ONCE(tcp_sk(mptcp_subflow_tcp_sock(subflow))->rcv_tstamp); if (subflow->stale_rcv_tstamp == rcv_tstamp) return false; mptcp_subflow_set_active(subflow); } return __mptcp_subflow_active(subflow); } /* implement the mptcp packet scheduler; * returns the subflow that will transmit the next DSS * additionally updates the rtx timeout */ static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk) { struct subflow_send_info send_info[2]; struct mptcp_subflow_context *subflow; struct sock *sk = (struct sock *)msk; int i, nr_active = 0; struct sock *ssk; long tout = 0; u64 ratio; u32 pace; sock_owned_by_me(sk); if (__mptcp_check_fallback(msk)) { if (!msk->first) return NULL; return sk_stream_memory_free(msk->first) ? msk->first : NULL; } /* re-use last subflow, if the burst allow that */ if (msk->last_snd && msk->snd_burst > 0 && sk_stream_memory_free(msk->last_snd) && mptcp_subflow_active(mptcp_subflow_ctx(msk->last_snd))) { mptcp_set_timeout(sk); return msk->last_snd; } /* pick the subflow with the lower wmem/wspace ratio */ for (i = 0; i < 2; ++i) { send_info[i].ssk = NULL; send_info[i].ratio = -1; } mptcp_for_each_subflow(msk, subflow) { trace_mptcp_subflow_get_send(subflow); ssk = mptcp_subflow_tcp_sock(subflow); if (!mptcp_subflow_active(subflow)) continue; tout = max(tout, mptcp_timeout_from_subflow(subflow)); nr_active += !subflow->backup; if (!sk_stream_memory_free(subflow->tcp_sock) || !tcp_sk(ssk)->snd_wnd) continue; pace = READ_ONCE(ssk->sk_pacing_rate); if (!pace) continue; ratio = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32, pace); if (ratio < send_info[subflow->backup].ratio) { send_info[subflow->backup].ssk = ssk; send_info[subflow->backup].ratio = ratio; } } __mptcp_set_timeout(sk, tout); /* pick the best backup if no other subflow is active */ if (!nr_active) send_info[0].ssk = send_info[1].ssk; if (send_info[0].ssk) { msk->last_snd = send_info[0].ssk; msk->snd_burst = min_t(int, MPTCP_SEND_BURST_SIZE, tcp_sk(msk->last_snd)->snd_wnd); return msk->last_snd; } return NULL; } static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info *info) { tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal); release_sock(ssk); } static void mptcp_update_post_push(struct mptcp_sock *msk, struct mptcp_data_frag *dfrag, u32 sent) { u64 snd_nxt_new = dfrag->data_seq; dfrag->already_sent += sent; msk->snd_burst -= sent; snd_nxt_new += dfrag->already_sent; /* snd_nxt_new can be smaller than snd_nxt in case mptcp * is recovering after a failover. In that event, this re-sends * old segments. * * Thus compute snd_nxt_new candidate based on * the dfrag->data_seq that was sent and the data * that has been handed to the subflow for transmission * and skip update in case it was old dfrag. */ if (likely(after64(snd_nxt_new, msk->snd_nxt))) msk->snd_nxt = snd_nxt_new; } static void mptcp_check_and_set_pending(struct sock *sk) { if (mptcp_send_head(sk) && !test_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags)) set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags); } void __mptcp_push_pending(struct sock *sk, unsigned int flags) { struct sock *prev_ssk = NULL, *ssk = NULL; struct mptcp_sock *msk = mptcp_sk(sk); struct mptcp_sendmsg_info info = { .flags = flags, }; struct mptcp_data_frag *dfrag; int len, copied = 0; while ((dfrag = mptcp_send_head(sk))) { info.sent = dfrag->already_sent; info.limit = dfrag->data_len; len = dfrag->data_len - dfrag->already_sent; while (len > 0) { int ret = 0; prev_ssk = ssk; __mptcp_flush_join_list(msk); ssk = mptcp_subflow_get_send(msk); /* First check. If the ssk has changed since * the last round, release prev_ssk */ if (ssk != prev_ssk && prev_ssk) mptcp_push_release(prev_ssk, &info); if (!ssk) goto out; /* Need to lock the new subflow only if different * from the previous one, otherwise we are still * helding the relevant lock */ if (ssk != prev_ssk) lock_sock(ssk); ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); if (ret <= 0) { mptcp_push_release(ssk, &info); goto out; } info.sent += ret; copied += ret; len -= ret; mptcp_update_post_push(msk, dfrag, ret); } WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); } /* at this point we held the socket lock for the last subflow we used */ if (ssk) mptcp_push_release(ssk, &info); out: /* ensure the rtx timer is running */ if (!mptcp_timer_pending(sk)) mptcp_reset_timer(sk); if (copied) __mptcp_check_send_data_fin(sk); } static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk) { struct mptcp_sock *msk = mptcp_sk(sk); struct mptcp_sendmsg_info info = { .data_lock_held = true, }; struct mptcp_data_frag *dfrag; struct sock *xmit_ssk; int len, copied = 0; bool first = true; info.flags = 0; while ((dfrag = mptcp_send_head(sk))) { info.sent = dfrag->already_sent; info.limit = dfrag->data_len; len = dfrag->data_len - dfrag->already_sent; while (len > 0) { int ret = 0; /* the caller already invoked the packet scheduler, * check for a different subflow usage only after * spooling the first chunk of data */ xmit_ssk = first ? ssk : mptcp_subflow_get_send(mptcp_sk(sk)); if (!xmit_ssk) goto out; if (xmit_ssk != ssk) { mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk), MPTCP_DELEGATE_SEND); goto out; } ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); if (ret <= 0) goto out; info.sent += ret; copied += ret; len -= ret; first = false; mptcp_update_post_push(msk, dfrag, ret); } WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); } out: /* __mptcp_alloc_tx_skb could have released some wmem and we are * not going to flush it via release_sock() */ if (copied) { tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, info.size_goal); if (!mptcp_timer_pending(sk)) mptcp_reset_timer(sk); if (msk->snd_data_fin_enable && msk->snd_nxt + 1 == msk->write_seq) mptcp_schedule_work(sk); } } static void mptcp_set_nospace(struct sock *sk) { /* enable autotune */ set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); /* will be cleared on avail space */ set_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags); } static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) { struct mptcp_sock *msk = mptcp_sk(sk); struct page_frag *pfrag; size_t copied = 0; int ret = 0; long timeo; /* we don't support FASTOPEN yet */ if (msg->msg_flags & MSG_FASTOPEN) return -EOPNOTSUPP; /* silently ignore everything else */ msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL; lock_sock(sk); timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) { ret = sk_stream_wait_connect(sk, &timeo); if (ret) goto out; } pfrag = sk_page_frag(sk); while (msg_data_left(msg)) { int total_ts, frag_truesize = 0; struct mptcp_data_frag *dfrag; bool dfrag_collapsed; size_t psize, offset; if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) { ret = -EPIPE; goto out; } /* reuse tail pfrag, if possible, or carve a new one from the * page allocator */ dfrag = mptcp_pending_tail(sk); dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag); if (!dfrag_collapsed) { if (!sk_stream_memory_free(sk)) goto wait_for_memory; if (!mptcp_page_frag_refill(sk, pfrag)) goto wait_for_memory; dfrag = mptcp_carve_data_frag(msk, pfrag, pfrag->offset); frag_truesize = dfrag->overhead; } /* we do not bound vs wspace, to allow a single packet. * memory accounting will prevent execessive memory usage * anyway */ offset = dfrag->offset + dfrag->data_len; psize = pfrag->size - offset; psize = min_t(size_t, psize, msg_data_left(msg)); total_ts = psize + frag_truesize; if (!sk_wmem_schedule(sk, total_ts)) goto wait_for_memory; if (copy_page_from_iter(dfrag->page, offset, psize, &msg->msg_iter) != psize) { ret = -EFAULT; goto out; } /* data successfully copied into the write queue */ sk->sk_forward_alloc -= total_ts; copied += psize; dfrag->data_len += psize; frag_truesize += psize; pfrag->offset += frag_truesize; WRITE_ONCE(msk->write_seq, msk->write_seq + psize); /* charge data on mptcp pending queue to the msk socket * Note: we charge such data both to sk and ssk */ sk_wmem_queued_add(sk, frag_truesize); if (!dfrag_collapsed) { get_page(dfrag->page); list_add_tail(&dfrag->list, &msk->rtx_queue); if (!msk->first_pending) WRITE_ONCE(msk->first_pending, dfrag); } pr_debug("msk=%p dfrag at seq=%llu len=%u sent=%u new=%d", msk, dfrag->data_seq, dfrag->data_len, dfrag->already_sent, !dfrag_collapsed); continue; wait_for_memory: mptcp_set_nospace(sk); __mptcp_push_pending(sk, msg->msg_flags); ret = sk_stream_wait_memory(sk, &timeo); if (ret) goto out; } if (copied) __mptcp_push_pending(sk, msg->msg_flags); out: release_sock(sk); return copied ? : ret; } static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk, struct msghdr *msg, size_t len, int flags, struct scm_timestamping_internal *tss, int *cmsg_flags) { struct sk_buff *skb, *tmp; int copied = 0; skb_queue_walk_safe(&msk->receive_queue, skb, tmp) { u32 offset = MPTCP_SKB_CB(skb)->offset; u32 data_len = skb->len - offset; u32 count = min_t(size_t, len - copied, data_len); int err; if (!(flags & MSG_TRUNC)) { err = skb_copy_datagram_msg(skb, offset, msg, count); if (unlikely(err < 0)) { if (!copied) return err; break; } } if (MPTCP_SKB_CB(skb)->has_rxtstamp) { tcp_update_recv_tstamps(skb, tss); *cmsg_flags |= MPTCP_CMSG_TS; } copied += count; if (count < data_len) { if (!(flags & MSG_PEEK)) MPTCP_SKB_CB(skb)->offset += count; break; } if (!(flags & MSG_PEEK)) { /* we will bulk release the skb memory later */ skb->destructor = NULL; WRITE_ONCE(msk->rmem_released, msk->rmem_released + skb->truesize); __skb_unlink(skb, &msk->receive_queue); __kfree_skb(skb); } if (copied >= len) break; } return copied; } /* receive buffer autotuning. See tcp_rcv_space_adjust for more information. * * Only difference: Use highest rtt estimate of the subflows in use. */ static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied) { struct mptcp_subflow_context *subflow; struct sock *sk = (struct sock *)msk; u32 time, advmss = 1; u64 rtt_us, mstamp; sock_owned_by_me(sk); if (copied <= 0) return; msk->rcvq_space.copied += copied; mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC); time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time); rtt_us = msk->rcvq_space.rtt_us; if (rtt_us && time < (rtt_us >> 3)) return; rtt_us = 0; mptcp_for_each_subflow(msk, subflow) { const struct tcp_sock *tp; u64 sf_rtt_us; u32 sf_advmss; tp = tcp_sk(mptcp_subflow_tcp_sock(subflow)); sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us); sf_advmss = READ_ONCE(tp->advmss); rtt_us = max(sf_rtt_us, rtt_us); advmss = max(sf_advmss, advmss); } msk->rcvq_space.rtt_us = rtt_us; if (time < (rtt_us >> 3) || rtt_us == 0) return; if (msk->rcvq_space.copied <= msk->rcvq_space.space) goto new_measure; if (sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf && !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { int rcvmem, rcvbuf; u64 rcvwin, grow; rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss; grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space); do_div(grow, msk->rcvq_space.space); rcvwin += (grow << 1); rcvmem = SKB_TRUESIZE(advmss + MAX_TCP_HEADER); while (tcp_win_from_space(sk, rcvmem) < advmss) rcvmem += 128; do_div(rcvwin, advmss); rcvbuf = min_t(u64, rcvwin * rcvmem, sock_net(sk)->ipv4.sysctl_tcp_rmem[2]); if (rcvbuf > sk->sk_rcvbuf) { u32 window_clamp; window_clamp = tcp_win_from_space(sk, rcvbuf); WRITE_ONCE(sk->sk_rcvbuf, rcvbuf); /* Make subflows follow along. If we do not do this, we * get drops at subflow level if skbs can't be moved to * the mptcp rx queue fast enough (announced rcv_win can * exceed ssk->sk_rcvbuf). */ mptcp_for_each_subflow(msk, subflow) { struct sock *ssk; bool slow; ssk = mptcp_subflow_tcp_sock(subflow); slow = lock_sock_fast(ssk); WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf); tcp_sk(ssk)->window_clamp = window_clamp; tcp_cleanup_rbuf(ssk, 1); unlock_sock_fast(ssk, slow); } } } msk->rcvq_space.space = msk->rcvq_space.copied; new_measure: msk->rcvq_space.copied = 0; msk->rcvq_space.time = mstamp; } static void __mptcp_update_rmem(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); if (!msk->rmem_released) return; atomic_sub(msk->rmem_released, &sk->sk_rmem_alloc); mptcp_rmem_uncharge(sk, msk->rmem_released); WRITE_ONCE(msk->rmem_released, 0); } static void __mptcp_splice_receive_queue(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue); } static bool __mptcp_move_skbs(struct mptcp_sock *msk) { struct sock *sk = (struct sock *)msk; unsigned int moved = 0; bool ret, done; mptcp_flush_join_list(msk); do { struct sock *ssk = mptcp_subflow_recv_lookup(msk); bool slowpath; /* we can have data pending in the subflows only if the msk * receive buffer was full at subflow_data_ready() time, * that is an unlikely slow path. */ if (likely(!ssk)) break; slowpath = lock_sock_fast(ssk); mptcp_data_lock(sk); __mptcp_update_rmem(sk); done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved); mptcp_data_unlock(sk); if (unlikely(ssk->sk_err)) __mptcp_error_report(sk); unlock_sock_fast(ssk, slowpath); } while (!done); /* acquire the data lock only if some input data is pending */ ret = moved > 0; if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) || !skb_queue_empty_lockless(&sk->sk_receive_queue)) { mptcp_data_lock(sk); __mptcp_update_rmem(sk); ret |= __mptcp_ofo_queue(msk); __mptcp_splice_receive_queue(sk); mptcp_data_unlock(sk); } if (ret) mptcp_check_data_fin((struct sock *)msk); return !skb_queue_empty(&msk->receive_queue); } static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock, int flags, int *addr_len) { struct mptcp_sock *msk = mptcp_sk(sk); struct scm_timestamping_internal tss; int copied = 0, cmsg_flags = 0; int target; long timeo; /* MSG_ERRQUEUE is really a no-op till we support IP_RECVERR */ if (unlikely(flags & MSG_ERRQUEUE)) return inet_recv_error(sk, msg, len, addr_len); lock_sock(sk); if (unlikely(sk->sk_state == TCP_LISTEN)) { copied = -ENOTCONN; goto out_err; } timeo = sock_rcvtimeo(sk, nonblock); len = min_t(size_t, len, INT_MAX); target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); while (copied < len) { int bytes_read; bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss, &cmsg_flags); if (unlikely(bytes_read < 0)) { if (!copied) copied = bytes_read; goto out_err; } copied += bytes_read; /* be sure to advertise window change */ mptcp_cleanup_rbuf(msk); if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk)) continue; /* only the master socket status is relevant here. The exit * conditions mirror closely tcp_recvmsg() */ if (copied >= target) break; if (copied) { if (sk->sk_err || sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN) || !timeo || signal_pending(current)) break; } else { if (sk->sk_err) { copied = sock_error(sk); break; } if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags)) mptcp_check_for_eof(msk); if (sk->sk_shutdown & RCV_SHUTDOWN) { /* race breaker: the shutdown could be after the * previous receive queue check */ if (__mptcp_move_skbs(msk)) continue; break; } if (sk->sk_state == TCP_CLOSE) { copied = -ENOTCONN; break; } if (!timeo) { copied = -EAGAIN; break; } if (signal_pending(current)) { copied = sock_intr_errno(timeo); break; } } pr_debug("block timeout %ld", timeo); sk_wait_data(sk, &timeo, NULL); } out_err: if (cmsg_flags && copied >= 0) { if (cmsg_flags & MPTCP_CMSG_TS) tcp_recv_timestamp(msg, sk, &tss); } pr_debug("msk=%p rx queue empty=%d:%d copied=%d", msk, skb_queue_empty_lockless(&sk->sk_receive_queue), skb_queue_empty(&msk->receive_queue), copied); if (!(flags & MSG_PEEK)) mptcp_rcv_space_adjust(msk, copied); release_sock(sk); return copied; } static void mptcp_retransmit_timer(struct timer_list *t) { struct inet_connection_sock *icsk = from_timer(icsk, t, icsk_retransmit_timer); struct sock *sk = &icsk->icsk_inet.sk; struct mptcp_sock *msk = mptcp_sk(sk); bh_lock_sock(sk); if (!sock_owned_by_user(sk)) { /* we need a process context to retransmit */ if (!test_and_set_bit(MPTCP_WORK_RTX, &msk->flags)) mptcp_schedule_work(sk); } else { /* delegate our work to tcp_release_cb() */ set_bit(MPTCP_RETRANSMIT, &msk->flags); } bh_unlock_sock(sk); sock_put(sk); } static void mptcp_timeout_timer(struct timer_list *t) { struct sock *sk = from_timer(sk, t, sk_timer); mptcp_schedule_work(sk); sock_put(sk); } /* Find an idle subflow. Return NULL if there is unacked data at tcp * level. * * A backup subflow is returned only if that is the only kind available. */ static struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk) { struct sock *backup = NULL, *pick = NULL; struct mptcp_subflow_context *subflow; int min_stale_count = INT_MAX; sock_owned_by_me((const struct sock *)msk); if (__mptcp_check_fallback(msk)) return NULL; mptcp_for_each_subflow(msk, subflow) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); if (!__mptcp_subflow_active(subflow)) continue; /* still data outstanding at TCP level? skip this */ if (!tcp_rtx_and_write_queues_empty(ssk)) { mptcp_pm_subflow_chk_stale(msk, ssk); min_stale_count = min_t(int, min_stale_count, subflow->stale_count); continue; } if (subflow->backup) { if (!backup) backup = ssk; continue; } if (!pick) pick = ssk; } if (pick) return pick; /* use backup only if there are no progresses anywhere */ return min_stale_count > 1 ? backup : NULL; } static void mptcp_dispose_initial_subflow(struct mptcp_sock *msk) { if (msk->subflow) { iput(SOCK_INODE(msk->subflow)); msk->subflow = NULL; } } bool __mptcp_retransmit_pending_data(struct sock *sk) { struct mptcp_data_frag *cur, *rtx_head; struct mptcp_sock *msk = mptcp_sk(sk); if (__mptcp_check_fallback(mptcp_sk(sk))) return false; if (tcp_rtx_and_write_queues_empty(sk)) return false; /* the closing socket has some data untransmitted and/or unacked: * some data in the mptcp rtx queue has not really xmitted yet. * keep it simple and re-inject the whole mptcp level rtx queue */ mptcp_data_lock(sk); __mptcp_clean_una_wakeup(sk); rtx_head = mptcp_rtx_head(sk); if (!rtx_head) { mptcp_data_unlock(sk); return false; } msk->recovery_snd_nxt = msk->snd_nxt; msk->recovery = true; mptcp_data_unlock(sk); msk->first_pending = rtx_head; msk->snd_burst = 0; /* be sure to clear the "sent status" on all re-injected fragments */ list_for_each_entry(cur, &msk->rtx_queue, list) { if (!cur->already_sent) break; cur->already_sent = 0; } return true; } /* subflow sockets can be either outgoing (connect) or incoming * (accept). * * Outgoing subflows use in-kernel sockets. * Incoming subflows do not have their own 'struct socket' allocated, * so we need to use tcp_close() after detaching them from the mptcp * parent socket. */ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, struct mptcp_subflow_context *subflow) { struct mptcp_sock *msk = mptcp_sk(sk); bool need_push; list_del(&subflow->node); lock_sock_nested(ssk, SINGLE_DEPTH_NESTING); /* if we are invoked by the msk cleanup code, the subflow is * already orphaned */ if (ssk->sk_socket) sock_orphan(ssk); need_push = __mptcp_retransmit_pending_data(sk); subflow->disposable = 1; /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops * the ssk has been already destroyed, we just need to release the * reference owned by msk; */ if (!inet_csk(ssk)->icsk_ulp_ops) { kfree_rcu(subflow, rcu); } else { /* otherwise tcp will dispose of the ssk and subflow ctx */ __tcp_close(ssk, 0); /* close acquired an extra ref */ __sock_put(ssk); } release_sock(ssk); sock_put(ssk); if (ssk == msk->last_snd) msk->last_snd = NULL; if (ssk == msk->first) msk->first = NULL; if (msk->subflow && ssk == msk->subflow->sk) mptcp_dispose_initial_subflow(msk); if (need_push) __mptcp_push_pending(sk, 0); } void mptcp_close_ssk(struct sock *sk, struct sock *ssk, struct mptcp_subflow_context *subflow) { if (sk->sk_state == TCP_ESTABLISHED) mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL); __mptcp_close_ssk(sk, ssk, subflow); } static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu) { return 0; } static void __mptcp_close_subflow(struct mptcp_sock *msk) { struct mptcp_subflow_context *subflow, *tmp; might_sleep(); list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); if (inet_sk_state_load(ssk) != TCP_CLOSE) continue; /* 'subflow_data_ready' will re-sched once rx queue is empty */ if (!skb_queue_empty_lockless(&ssk->sk_receive_queue)) continue; mptcp_close_ssk((struct sock *)msk, ssk, subflow); } } static bool mptcp_check_close_timeout(const struct sock *sk) { s32 delta = tcp_jiffies32 - inet_csk(sk)->icsk_mtup.probe_timestamp; struct mptcp_subflow_context *subflow; if (delta >= TCP_TIMEWAIT_LEN) return true; /* if all subflows are in closed status don't bother with additional * timeout */ mptcp_for_each_subflow(mptcp_sk(sk), subflow) { if (inet_sk_state_load(mptcp_subflow_tcp_sock(subflow)) != TCP_CLOSE) return false; } return true; } static void mptcp_check_fastclose(struct mptcp_sock *msk) { struct mptcp_subflow_context *subflow, *tmp; struct sock *sk = &msk->sk.icsk_inet.sk; if (likely(!READ_ONCE(msk->rcv_fastclose))) return; mptcp_token_destroy(msk); list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) { struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); bool slow; slow = lock_sock_fast(tcp_sk); if (tcp_sk->sk_state != TCP_CLOSE) { tcp_send_active_reset(tcp_sk, GFP_ATOMIC); tcp_set_state(tcp_sk, TCP_CLOSE); } unlock_sock_fast(tcp_sk, slow); } inet_sk_state_store(sk, TCP_CLOSE); sk->sk_shutdown = SHUTDOWN_MASK; smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags); mptcp_close_wake_up(sk); } static void __mptcp_retrans(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); struct mptcp_sendmsg_info info = {}; struct mptcp_data_frag *dfrag; size_t copied = 0; struct sock *ssk; int ret; mptcp_clean_una_wakeup(sk); /* first check ssk: need to kick "stale" logic */ ssk = mptcp_subflow_get_retrans(msk); dfrag = mptcp_rtx_head(sk); if (!dfrag) { if (mptcp_data_fin_enabled(msk)) { struct inet_connection_sock *icsk = inet_csk(sk); icsk->icsk_retransmits++; mptcp_set_datafin_timeout(sk); mptcp_send_ack(msk); goto reset_timer; } if (!mptcp_send_head(sk)) return; goto reset_timer; } if (!ssk) goto reset_timer; lock_sock(ssk); /* limit retransmission to the bytes already sent on some subflows */ info.sent = 0; info.limit = READ_ONCE(msk->csum_enabled) ? dfrag->data_len : dfrag->already_sent; while (info.sent < info.limit) { ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); if (ret <= 0) break; MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS); copied += ret; info.sent += ret; } if (copied) { dfrag->already_sent = max(dfrag->already_sent, info.sent); tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, info.size_goal); } release_sock(ssk); reset_timer: mptcp_check_and_set_pending(sk); if (!mptcp_timer_pending(sk)) mptcp_reset_timer(sk); } static void mptcp_worker(struct work_struct *work) { struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work); struct sock *sk = &msk->sk.icsk_inet.sk; int state; lock_sock(sk); state = sk->sk_state; if (unlikely(state == TCP_CLOSE)) goto unlock; mptcp_check_data_fin_ack(sk); mptcp_flush_join_list(msk); mptcp_check_fastclose(msk); if (msk->pm.status) mptcp_pm_nl_work(msk); if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags)) mptcp_check_for_eof(msk); __mptcp_check_send_data_fin(sk); mptcp_check_data_fin(sk); /* There is no point in keeping around an orphaned sk timedout or * closed, but we need the msk around to reply to incoming DATA_FIN, * even if it is orphaned and in FIN_WAIT2 state */ if (sock_flag(sk, SOCK_DEAD) && (mptcp_check_close_timeout(sk) || sk->sk_state == TCP_CLOSE)) { inet_sk_state_store(sk, TCP_CLOSE); __mptcp_destroy_sock(sk); goto unlock; } if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags)) __mptcp_close_subflow(msk); if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags)) __mptcp_retrans(sk); unlock: release_sock(sk); sock_put(sk); } static int __mptcp_init_sock(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); spin_lock_init(&msk->join_list_lock); INIT_LIST_HEAD(&msk->conn_list); INIT_LIST_HEAD(&msk->join_list); INIT_LIST_HEAD(&msk->rtx_queue); INIT_WORK(&msk->work, mptcp_worker); __skb_queue_head_init(&msk->receive_queue); msk->out_of_order_queue = RB_ROOT; msk->first_pending = NULL; msk->rmem_fwd_alloc = 0; WRITE_ONCE(msk->rmem_released, 0); msk->timer_ival = TCP_RTO_MIN; msk->first = NULL; inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss; WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk))); msk->recovery = false; mptcp_pm_data_init(msk); /* re-use the csk retrans timer for MPTCP-level retrans */ timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0); timer_setup(&sk->sk_timer, mptcp_timeout_timer, 0); return 0; } static int mptcp_init_sock(struct sock *sk) { struct inet_connection_sock *icsk = inet_csk(sk); struct net *net = sock_net(sk); int ret; ret = __mptcp_init_sock(sk); if (ret) return ret; if (!mptcp_is_enabled(net)) return -ENOPROTOOPT; if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net)) return -ENOMEM; ret = __mptcp_socket_create(mptcp_sk(sk)); if (ret) return ret; /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will * propagate the correct value */ tcp_assign_congestion_control(sk); strcpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name); /* no need to keep a reference to the ops, the name will suffice */ tcp_cleanup_congestion_control(sk); icsk->icsk_ca_ops = NULL; sk_sockets_allocated_inc(sk); sk->sk_rcvbuf = sock_net(sk)->ipv4.sysctl_tcp_rmem[1]; sk->sk_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[1]; return 0; } static void __mptcp_clear_xmit(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); struct mptcp_data_frag *dtmp, *dfrag; WRITE_ONCE(msk->first_pending, NULL); list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) dfrag_clear(sk, dfrag); } static void mptcp_cancel_work(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); if (cancel_work_sync(&msk->work)) __sock_put(sk); } void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how) { lock_sock(ssk); switch (ssk->sk_state) { case TCP_LISTEN: if (!(how & RCV_SHUTDOWN)) break; fallthrough; case TCP_SYN_SENT: tcp_disconnect(ssk, O_NONBLOCK); break; default: if (__mptcp_check_fallback(mptcp_sk(sk))) { pr_debug("Fallback"); ssk->sk_shutdown |= how; tcp_shutdown(ssk, how); } else { pr_debug("Sending DATA_FIN on subflow %p", ssk); tcp_send_ack(ssk); if (!mptcp_timer_pending(sk)) mptcp_reset_timer(sk); } break; } release_sock(ssk); } static const unsigned char new_state[16] = { /* current state: new state: action: */ [0 /* (Invalid) */] = TCP_CLOSE, [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, [TCP_SYN_SENT] = TCP_CLOSE, [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, [TCP_FIN_WAIT1] = TCP_FIN_WAIT1, [TCP_FIN_WAIT2] = TCP_FIN_WAIT2, [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */ [TCP_CLOSE] = TCP_CLOSE, [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN, [TCP_LAST_ACK] = TCP_LAST_ACK, [TCP_LISTEN] = TCP_CLOSE, [TCP_CLOSING] = TCP_CLOSING, [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */ }; static int mptcp_close_state(struct sock *sk) { int next = (int)new_state[sk->sk_state]; int ns = next & TCP_STATE_MASK; inet_sk_state_store(sk, ns); return next & TCP_ACTION_FIN; } static void __mptcp_check_send_data_fin(struct sock *sk) { struct mptcp_subflow_context *subflow; struct mptcp_sock *msk = mptcp_sk(sk); pr_debug("msk=%p snd_data_fin_enable=%d pending=%d snd_nxt=%llu write_seq=%llu", msk, msk->snd_data_fin_enable, !!mptcp_send_head(sk), msk->snd_nxt, msk->write_seq); /* we still need to enqueue subflows or not really shutting down, * skip this */ if (!msk->snd_data_fin_enable || msk->snd_nxt + 1 != msk->write_seq || mptcp_send_head(sk)) return; WRITE_ONCE(msk->snd_nxt, msk->write_seq); /* fallback socket will not get data_fin/ack, can move to the next * state now */ if (__mptcp_check_fallback(msk)) { if ((1 << sk->sk_state) & (TCPF_CLOSING | TCPF_LAST_ACK)) { inet_sk_state_store(sk, TCP_CLOSE); mptcp_close_wake_up(sk); } else if (sk->sk_state == TCP_FIN_WAIT1) { inet_sk_state_store(sk, TCP_FIN_WAIT2); } } mptcp_flush_join_list(msk); mptcp_for_each_subflow(msk, subflow) { struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); mptcp_subflow_shutdown(sk, tcp_sk, SEND_SHUTDOWN); } } static void __mptcp_wr_shutdown(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); pr_debug("msk=%p snd_data_fin_enable=%d shutdown=%x state=%d pending=%d", msk, msk->snd_data_fin_enable, sk->sk_shutdown, sk->sk_state, !!mptcp_send_head(sk)); /* will be ignored by fallback sockets */ WRITE_ONCE(msk->write_seq, msk->write_seq + 1); WRITE_ONCE(msk->snd_data_fin_enable, 1); __mptcp_check_send_data_fin(sk); } static void __mptcp_destroy_sock(struct sock *sk) { struct mptcp_subflow_context *subflow, *tmp; struct mptcp_sock *msk = mptcp_sk(sk); LIST_HEAD(conn_list); pr_debug("msk=%p", msk); might_sleep(); /* be sure to always acquire the join list lock, to sync vs * mptcp_finish_join(). */ spin_lock_bh(&msk->join_list_lock); list_splice_tail_init(&msk->join_list, &msk->conn_list); spin_unlock_bh(&msk->join_list_lock); list_splice_init(&msk->conn_list, &conn_list); sk_stop_timer(sk, &msk->sk.icsk_retransmit_timer); sk_stop_timer(sk, &sk->sk_timer); msk->pm.status = 0; list_for_each_entry_safe(subflow, tmp, &conn_list, node) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); __mptcp_close_ssk(sk, ssk, subflow); } sk->sk_prot->destroy(sk); WARN_ON_ONCE(msk->rmem_fwd_alloc); WARN_ON_ONCE(msk->rmem_released); sk_stream_kill_queues(sk); xfrm_sk_free_policy(sk); sk_refcnt_debug_release(sk); mptcp_dispose_initial_subflow(msk); sock_put(sk); } static void mptcp_close(struct sock *sk, long timeout) { struct mptcp_subflow_context *subflow; bool do_cancel_work = false; lock_sock(sk); sk->sk_shutdown = SHUTDOWN_MASK; if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) { inet_sk_state_store(sk, TCP_CLOSE); goto cleanup; } if (mptcp_close_state(sk)) __mptcp_wr_shutdown(sk); sk_stream_wait_close(sk, timeout); cleanup: /* orphan all the subflows */ inet_csk(sk)->icsk_mtup.probe_timestamp = tcp_jiffies32; mptcp_for_each_subflow(mptcp_sk(sk), subflow) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); bool slow = lock_sock_fast_nested(ssk); sock_orphan(ssk); unlock_sock_fast(ssk, slow); } sock_orphan(sk); sock_hold(sk); pr_debug("msk=%p state=%d", sk, sk->sk_state); if (sk->sk_state == TCP_CLOSE) { __mptcp_destroy_sock(sk); do_cancel_work = true; } else { sk_reset_timer(sk, &sk->sk_timer, jiffies + TCP_TIMEWAIT_LEN); } release_sock(sk); if (do_cancel_work) mptcp_cancel_work(sk); if (mptcp_sk(sk)->token) mptcp_event(MPTCP_EVENT_CLOSED, mptcp_sk(sk), NULL, GFP_KERNEL); sock_put(sk); } static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk) { #if IS_ENABLED(CONFIG_MPTCP_IPV6) const struct ipv6_pinfo *ssk6 = inet6_sk(ssk); struct ipv6_pinfo *msk6 = inet6_sk(msk); msk->sk_v6_daddr = ssk->sk_v6_daddr; msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr; if (msk6 && ssk6) { msk6->saddr = ssk6->saddr; msk6->flow_label = ssk6->flow_label; } #endif inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num; inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport; inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport; inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr; inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr; inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr; } static int mptcp_disconnect(struct sock *sk, int flags) { struct mptcp_subflow_context *subflow; struct mptcp_sock *msk = mptcp_sk(sk); mptcp_do_flush_join_list(msk); mptcp_for_each_subflow(msk, subflow) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); lock_sock(ssk); tcp_disconnect(ssk, flags); release_sock(ssk); } return 0; } #if IS_ENABLED(CONFIG_MPTCP_IPV6) static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk) { unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo); return (struct ipv6_pinfo *)(((u8 *)sk) + offset); } #endif struct sock *mptcp_sk_clone(const struct sock *sk, const struct mptcp_options_received *mp_opt, struct request_sock *req) { struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC); struct mptcp_sock *msk; u64 ack_seq; if (!nsk) return NULL; #if IS_ENABLED(CONFIG_MPTCP_IPV6) if (nsk->sk_family == AF_INET6) inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk); #endif __mptcp_init_sock(nsk); msk = mptcp_sk(nsk); msk->local_key = subflow_req->local_key; msk->token = subflow_req->token; msk->subflow = NULL; WRITE_ONCE(msk->fully_established, false); if (mp_opt->suboptions & OPTION_MPTCP_CSUMREQD) WRITE_ONCE(msk->csum_enabled, true); msk->write_seq = subflow_req->idsn + 1; msk->snd_nxt = msk->write_seq; msk->snd_una = msk->write_seq; msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd; msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq; if (mp_opt->suboptions & OPTIONS_MPTCP_MPC) { msk->can_ack = true; msk->remote_key = mp_opt->sndr_key; mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq); ack_seq++; WRITE_ONCE(msk->ack_seq, ack_seq); WRITE_ONCE(msk->rcv_wnd_sent, ack_seq); } sock_reset_flag(nsk, SOCK_RCU_FREE); /* will be fully established after successful MPC subflow creation */ inet_sk_state_store(nsk, TCP_SYN_RECV); security_inet_csk_clone(nsk, req); bh_unlock_sock(nsk); /* keep a single reference */ __sock_put(nsk); return nsk; } void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk) { const struct tcp_sock *tp = tcp_sk(ssk); msk->rcvq_space.copied = 0; msk->rcvq_space.rtt_us = 0; msk->rcvq_space.time = tp->tcp_mstamp; /* initial rcv_space offering made to peer */ msk->rcvq_space.space = min_t(u32, tp->rcv_wnd, TCP_INIT_CWND * tp->advmss); if (msk->rcvq_space.space == 0) msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT; WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd); } static struct sock *mptcp_accept(struct sock *sk, int flags, int *err, bool kern) { struct mptcp_sock *msk = mptcp_sk(sk); struct socket *listener; struct sock *newsk; listener = __mptcp_nmpc_socket(msk); if (WARN_ON_ONCE(!listener)) { *err = -EINVAL; return NULL; } pr_debug("msk=%p, listener=%p", msk, mptcp_subflow_ctx(listener->sk)); newsk = inet_csk_accept(listener->sk, flags, err, kern); if (!newsk) return NULL; pr_debug("msk=%p, subflow is mptcp=%d", msk, sk_is_mptcp(newsk)); if (sk_is_mptcp(newsk)) { struct mptcp_subflow_context *subflow; struct sock *new_mptcp_sock; subflow = mptcp_subflow_ctx(newsk); new_mptcp_sock = subflow->conn; /* is_mptcp should be false if subflow->conn is missing, see * subflow_syn_recv_sock() */ if (WARN_ON_ONCE(!new_mptcp_sock)) { tcp_sk(newsk)->is_mptcp = 0; goto out; } /* acquire the 2nd reference for the owning socket */ sock_hold(new_mptcp_sock); newsk = new_mptcp_sock; MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK); } else { MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK); } out: newsk->sk_kern_sock = kern; return newsk; } void mptcp_destroy_common(struct mptcp_sock *msk) { struct sock *sk = (struct sock *)msk; __mptcp_clear_xmit(sk); /* move to sk_receive_queue, sk_stream_kill_queues will purge it */ skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue); __skb_queue_purge(&sk->sk_receive_queue); skb_rbtree_purge(&msk->out_of_order_queue); /* move all the rx fwd alloc into the sk_mem_reclaim_final in * inet_sock_destruct() will dispose it */ sk->sk_forward_alloc += msk->rmem_fwd_alloc; msk->rmem_fwd_alloc = 0; mptcp_token_destroy(msk); mptcp_pm_free_anno_list(msk); } static void mptcp_destroy(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); mptcp_destroy_common(msk); sk_sockets_allocated_dec(sk); } void __mptcp_data_acked(struct sock *sk) { if (!sock_owned_by_user(sk)) __mptcp_clean_una(sk); else set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->flags); if (mptcp_pending_data_fin_ack(sk)) mptcp_schedule_work(sk); } void __mptcp_check_push(struct sock *sk, struct sock *ssk) { if (!mptcp_send_head(sk)) return; if (!sock_owned_by_user(sk)) { struct sock *xmit_ssk = mptcp_subflow_get_send(mptcp_sk(sk)); if (xmit_ssk == ssk) __mptcp_subflow_push_pending(sk, ssk); else if (xmit_ssk) mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk), MPTCP_DELEGATE_SEND); } else { set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags); } } /* processes deferred events and flush wmem */ static void mptcp_release_cb(struct sock *sk) { for (;;) { unsigned long flags = 0; if (test_and_clear_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags)) flags |= BIT(MPTCP_PUSH_PENDING); if (test_and_clear_bit(MPTCP_RETRANSMIT, &mptcp_sk(sk)->flags)) flags |= BIT(MPTCP_RETRANSMIT); if (!flags) break; /* the following actions acquire the subflow socket lock * * 1) can't be invoked in atomic scope * 2) must avoid ABBA deadlock with msk socket spinlock: the RX * datapath acquires the msk socket spinlock while helding * the subflow socket lock */ spin_unlock_bh(&sk->sk_lock.slock); if (flags & BIT(MPTCP_PUSH_PENDING)) __mptcp_push_pending(sk, 0); if (flags & BIT(MPTCP_RETRANSMIT)) __mptcp_retrans(sk); cond_resched(); spin_lock_bh(&sk->sk_lock.slock); } /* be sure to set the current sk state before tacking actions * depending on sk_state */ if (test_and_clear_bit(MPTCP_CONNECTED, &mptcp_sk(sk)->flags)) __mptcp_set_connected(sk); if (test_and_clear_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->flags)) __mptcp_clean_una_wakeup(sk); if (test_and_clear_bit(MPTCP_ERROR_REPORT, &mptcp_sk(sk)->flags)) __mptcp_error_report(sk); __mptcp_update_rmem(sk); } /* MP_JOIN client subflow must wait for 4th ack before sending any data: * TCP can't schedule delack timer before the subflow is fully established. * MPTCP uses the delack timer to do 3rd ack retransmissions */ static void schedule_3rdack_retransmission(struct sock *ssk) { struct inet_connection_sock *icsk = inet_csk(ssk); struct tcp_sock *tp = tcp_sk(ssk); unsigned long timeout; if (mptcp_subflow_ctx(ssk)->fully_established) return; /* reschedule with a timeout above RTT, as we must look only for drop */ if (tp->srtt_us) timeout = usecs_to_jiffies(tp->srtt_us >> (3 - 1)); else timeout = TCP_TIMEOUT_INIT; timeout += jiffies; WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER); icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; icsk->icsk_ack.timeout = timeout; sk_reset_timer(ssk, &icsk->icsk_delack_timer, timeout); } void mptcp_subflow_process_delegated(struct sock *ssk) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); struct sock *sk = subflow->conn; if (test_bit(MPTCP_DELEGATE_SEND, &subflow->delegated_status)) { mptcp_data_lock(sk); if (!sock_owned_by_user(sk)) __mptcp_subflow_push_pending(sk, ssk); else set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags); mptcp_data_unlock(sk); mptcp_subflow_delegated_done(subflow, MPTCP_DELEGATE_SEND); } if (test_bit(MPTCP_DELEGATE_ACK, &subflow->delegated_status)) { schedule_3rdack_retransmission(ssk); mptcp_subflow_delegated_done(subflow, MPTCP_DELEGATE_ACK); } } static int mptcp_hash(struct sock *sk) { /* should never be called, * we hash the TCP subflows not the master socket */ WARN_ON_ONCE(1); return 0; } static void mptcp_unhash(struct sock *sk) { /* called from sk_common_release(), but nothing to do here */ } static int mptcp_get_port(struct sock *sk, unsigned short snum) { struct mptcp_sock *msk = mptcp_sk(sk); struct socket *ssock; ssock = __mptcp_nmpc_socket(msk); pr_debug("msk=%p, subflow=%p", msk, ssock); if (WARN_ON_ONCE(!ssock)) return -EINVAL; return inet_csk_get_port(ssock->sk, snum); } void mptcp_finish_connect(struct sock *ssk) { struct mptcp_subflow_context *subflow; struct mptcp_sock *msk; struct sock *sk; u64 ack_seq; subflow = mptcp_subflow_ctx(ssk); sk = subflow->conn; msk = mptcp_sk(sk); pr_debug("msk=%p, token=%u", sk, subflow->token); mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq); ack_seq++; subflow->map_seq = ack_seq; subflow->map_subflow_seq = 1; /* the socket is not connected yet, no msk/subflow ops can access/race * accessing the field below */ WRITE_ONCE(msk->remote_key, subflow->remote_key); WRITE_ONCE(msk->local_key, subflow->local_key); WRITE_ONCE(msk->write_seq, subflow->idsn + 1); WRITE_ONCE(msk->snd_nxt, msk->write_seq); WRITE_ONCE(msk->ack_seq, ack_seq); WRITE_ONCE(msk->rcv_wnd_sent, ack_seq); WRITE_ONCE(msk->can_ack, 1); WRITE_ONCE(msk->snd_una, msk->write_seq); mptcp_pm_new_connection(msk, ssk, 0); mptcp_rcv_space_init(msk, ssk); } void mptcp_sock_graft(struct sock *sk, struct socket *parent) { write_lock_bh(&sk->sk_callback_lock); rcu_assign_pointer(sk->sk_wq, &parent->wq); sk_set_socket(sk, parent); sk->sk_uid = SOCK_INODE(parent)->i_uid; write_unlock_bh(&sk->sk_callback_lock); } bool mptcp_finish_join(struct sock *ssk) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); struct mptcp_sock *msk = mptcp_sk(subflow->conn); struct sock *parent = (void *)msk; struct socket *parent_sock; bool ret; pr_debug("msk=%p, subflow=%p", msk, subflow); /* mptcp socket already closing? */ if (!mptcp_is_fully_established(parent)) { subflow->reset_reason = MPTCP_RST_EMPTCP; return false; } if (!msk->pm.server_side) goto out; if (!mptcp_pm_allow_new_subflow(msk)) { subflow->reset_reason = MPTCP_RST_EPROHIBIT; return false; } /* active connections are already on conn_list, and we can't acquire * msk lock here. * use the join list lock as synchronization point and double-check * msk status to avoid racing with __mptcp_destroy_sock() */ spin_lock_bh(&msk->join_list_lock); ret = inet_sk_state_load(parent) == TCP_ESTABLISHED; if (ret && !WARN_ON_ONCE(!list_empty(&subflow->node))) { list_add_tail(&subflow->node, &msk->join_list); sock_hold(ssk); } spin_unlock_bh(&msk->join_list_lock); if (!ret) { subflow->reset_reason = MPTCP_RST_EPROHIBIT; return false; } /* attach to msk socket only after we are sure he will deal with us * at close time */ parent_sock = READ_ONCE(parent->sk_socket); if (parent_sock && !ssk->sk_socket) mptcp_sock_graft(ssk, parent_sock); subflow->map_seq = READ_ONCE(msk->ack_seq); out: mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC); return true; } static void mptcp_shutdown(struct sock *sk, int how) { pr_debug("sk=%p, how=%d", sk, how); if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk)) __mptcp_wr_shutdown(sk); } static int mptcp_forward_alloc_get(const struct sock *sk) { return sk->sk_forward_alloc + mptcp_sk(sk)->rmem_fwd_alloc; } static struct proto mptcp_prot = { .name = "MPTCP", .owner = THIS_MODULE, .init = mptcp_init_sock, .disconnect = mptcp_disconnect, .close = mptcp_close, .accept = mptcp_accept, .setsockopt = mptcp_setsockopt, .getsockopt = mptcp_getsockopt, .shutdown = mptcp_shutdown, .destroy = mptcp_destroy, .sendmsg = mptcp_sendmsg, .recvmsg = mptcp_recvmsg, .release_cb = mptcp_release_cb, .hash = mptcp_hash, .unhash = mptcp_unhash, .get_port = mptcp_get_port, .forward_alloc_get = mptcp_forward_alloc_get, .sockets_allocated = &mptcp_sockets_allocated, .memory_allocated = &tcp_memory_allocated, .memory_pressure = &tcp_memory_pressure, .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem), .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem), .sysctl_mem = sysctl_tcp_mem, .obj_size = sizeof(struct mptcp_sock), .slab_flags = SLAB_TYPESAFE_BY_RCU, .no_autobind = true, }; static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) { struct mptcp_sock *msk = mptcp_sk(sock->sk); struct socket *ssock; int err; lock_sock(sock->sk); ssock = __mptcp_nmpc_socket(msk); if (!ssock) { err = -EINVAL; goto unlock; } err = ssock->ops->bind(ssock, uaddr, addr_len); if (!err) mptcp_copy_inaddrs(sock->sk, ssock->sk); unlock: release_sock(sock->sk); return err; } static void mptcp_subflow_early_fallback(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow) { subflow->request_mptcp = 0; __mptcp_do_fallback(msk); } static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr, int addr_len, int flags) { struct mptcp_sock *msk = mptcp_sk(sock->sk); struct mptcp_subflow_context *subflow; struct socket *ssock; int err; lock_sock(sock->sk); if (sock->state != SS_UNCONNECTED && msk->subflow) { /* pending connection or invalid state, let existing subflow * cope with that */ ssock = msk->subflow; goto do_connect; } ssock = __mptcp_nmpc_socket(msk); if (!ssock) { err = -EINVAL; goto unlock; } mptcp_token_destroy(msk); inet_sk_state_store(sock->sk, TCP_SYN_SENT); subflow = mptcp_subflow_ctx(ssock->sk); #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(ssock->sk)->md5sig_info)) mptcp_subflow_early_fallback(msk, subflow); #endif if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk)) { MPTCP_INC_STATS(sock_net(ssock->sk), MPTCP_MIB_TOKENFALLBACKINIT); mptcp_subflow_early_fallback(msk, subflow); } if (likely(!__mptcp_check_fallback(msk))) MPTCP_INC_STATS(sock_net(sock->sk), MPTCP_MIB_MPCAPABLEACTIVE); do_connect: err = ssock->ops->connect(ssock, uaddr, addr_len, flags); sock->state = ssock->state; /* on successful connect, the msk state will be moved to established by * subflow_finish_connect() */ if (!err || err == -EINPROGRESS) mptcp_copy_inaddrs(sock->sk, ssock->sk); else inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk)); unlock: release_sock(sock->sk); return err; } static int mptcp_listen(struct socket *sock, int backlog) { struct mptcp_sock *msk = mptcp_sk(sock->sk); struct socket *ssock; int err; pr_debug("msk=%p", msk); lock_sock(sock->sk); ssock = __mptcp_nmpc_socket(msk); if (!ssock) { err = -EINVAL; goto unlock; } mptcp_token_destroy(msk); inet_sk_state_store(sock->sk, TCP_LISTEN); sock_set_flag(sock->sk, SOCK_RCU_FREE); err = ssock->ops->listen(ssock, backlog); inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk)); if (!err) mptcp_copy_inaddrs(sock->sk, ssock->sk); unlock: release_sock(sock->sk); return err; } static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, int flags, bool kern) { struct mptcp_sock *msk = mptcp_sk(sock->sk); struct socket *ssock; int err; pr_debug("msk=%p", msk); lock_sock(sock->sk); if (sock->sk->sk_state != TCP_LISTEN) goto unlock_fail; ssock = __mptcp_nmpc_socket(msk); if (!ssock) goto unlock_fail; clear_bit(MPTCP_DATA_READY, &msk->flags); sock_hold(ssock->sk); release_sock(sock->sk); err = ssock->ops->accept(sock, newsock, flags, kern); if (err == 0 && !mptcp_is_tcpsk(newsock->sk)) { struct mptcp_sock *msk = mptcp_sk(newsock->sk); struct mptcp_subflow_context *subflow; struct sock *newsk = newsock->sk; lock_sock(newsk); /* PM/worker can now acquire the first subflow socket * lock without racing with listener queue cleanup, * we can notify it, if needed. * * Even if remote has reset the initial subflow by now * the refcnt is still at least one. */ subflow = mptcp_subflow_ctx(msk->first); list_add(&subflow->node, &msk->conn_list); sock_hold(msk->first); if (mptcp_is_fully_established(newsk)) mptcp_pm_fully_established(msk, msk->first, GFP_KERNEL); mptcp_copy_inaddrs(newsk, msk->first); mptcp_rcv_space_init(msk, msk->first); mptcp_propagate_sndbuf(newsk, msk->first); /* set ssk->sk_socket of accept()ed flows to mptcp socket. * This is needed so NOSPACE flag can be set from tcp stack. */ mptcp_flush_join_list(msk); mptcp_for_each_subflow(msk, subflow) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); if (!ssk->sk_socket) mptcp_sock_graft(ssk, newsock); } release_sock(newsk); } if (inet_csk_listen_poll(ssock->sk)) set_bit(MPTCP_DATA_READY, &msk->flags); sock_put(ssock->sk); return err; unlock_fail: release_sock(sock->sk); return -EINVAL; } static __poll_t mptcp_check_readable(struct mptcp_sock *msk) { /* Concurrent splices from sk_receive_queue into receive_queue will * always show at least one non-empty queue when checked in this order. */ if (skb_queue_empty_lockless(&((struct sock *)msk)->sk_receive_queue) && skb_queue_empty_lockless(&msk->receive_queue)) return 0; return EPOLLIN | EPOLLRDNORM; } static __poll_t mptcp_check_writeable(struct mptcp_sock *msk) { struct sock *sk = (struct sock *)msk; if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN)) return EPOLLOUT | EPOLLWRNORM; if (sk_stream_is_writeable(sk)) return EPOLLOUT | EPOLLWRNORM; mptcp_set_nospace(sk); smp_mb__after_atomic(); /* msk->flags is changed by write_space cb */ if (sk_stream_is_writeable(sk)) return EPOLLOUT | EPOLLWRNORM; return 0; } static __poll_t mptcp_poll(struct file *file, struct socket *sock, struct poll_table_struct *wait) { struct sock *sk = sock->sk; struct mptcp_sock *msk; __poll_t mask = 0; int state; msk = mptcp_sk(sk); sock_poll_wait(file, sock, wait); state = inet_sk_state_load(sk); pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags); if (state == TCP_LISTEN) return test_bit(MPTCP_DATA_READY, &msk->flags) ? EPOLLIN | EPOLLRDNORM : 0; if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) { mask |= mptcp_check_readable(msk); mask |= mptcp_check_writeable(msk); } if (sk->sk_shutdown == SHUTDOWN_MASK || state == TCP_CLOSE) mask |= EPOLLHUP; if (sk->sk_shutdown & RCV_SHUTDOWN) mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP; /* This barrier is coupled with smp_wmb() in tcp_reset() */ smp_rmb(); if (sk->sk_err) mask |= EPOLLERR; return mask; } static const struct proto_ops mptcp_stream_ops = { .family = PF_INET, .owner = THIS_MODULE, .release = inet_release, .bind = mptcp_bind, .connect = mptcp_stream_connect, .socketpair = sock_no_socketpair, .accept = mptcp_stream_accept, .getname = inet_getname, .poll = mptcp_poll, .ioctl = inet_ioctl, .gettstamp = sock_gettstamp, .listen = mptcp_listen, .shutdown = inet_shutdown, .setsockopt = sock_common_setsockopt, .getsockopt = sock_common_getsockopt, .sendmsg = inet_sendmsg, .recvmsg = inet_recvmsg, .mmap = sock_no_mmap, .sendpage = inet_sendpage, }; static struct inet_protosw mptcp_protosw = { .type = SOCK_STREAM, .protocol = IPPROTO_MPTCP, .prot = &mptcp_prot, .ops = &mptcp_stream_ops, .flags = INET_PROTOSW_ICSK, }; static int mptcp_napi_poll(struct napi_struct *napi, int budget) { struct mptcp_delegated_action *delegated; struct mptcp_subflow_context *subflow; int work_done = 0; delegated = container_of(napi, struct mptcp_delegated_action, napi); while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); bh_lock_sock_nested(ssk); if (!sock_owned_by_user(ssk) && mptcp_subflow_has_delegated_action(subflow)) mptcp_subflow_process_delegated(ssk); /* ... elsewhere tcp_release_cb_override already processed * the action or will do at next release_sock(). * In both case must dequeue the subflow here - on the same * CPU that scheduled it. */ bh_unlock_sock(ssk); sock_put(ssk); if (++work_done == budget) return budget; } /* always provide a 0 'work_done' argument, so that napi_complete_done * will not try accessing the NULL napi->dev ptr */ napi_complete_done(napi, 0); return work_done; } void __init mptcp_proto_init(void) { struct mptcp_delegated_action *delegated; int cpu; mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo; if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL)) panic("Failed to allocate MPTCP pcpu counter\n"); init_dummy_netdev(&mptcp_napi_dev); for_each_possible_cpu(cpu) { delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu); INIT_LIST_HEAD(&delegated->head); netif_tx_napi_add(&mptcp_napi_dev, &delegated->napi, mptcp_napi_poll, NAPI_POLL_WEIGHT); napi_enable(&delegated->napi); } mptcp_subflow_init(); mptcp_pm_init(); mptcp_token_init(); if (proto_register(&mptcp_prot, 1) != 0) panic("Failed to register MPTCP proto.\n"); inet_register_protosw(&mptcp_protosw); BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb)); } #if IS_ENABLED(CONFIG_MPTCP_IPV6) static const struct proto_ops mptcp_v6_stream_ops = { .family = PF_INET6, .owner = THIS_MODULE, .release = inet6_release, .bind = mptcp_bind, .connect = mptcp_stream_connect, .socketpair = sock_no_socketpair, .accept = mptcp_stream_accept, .getname = inet6_getname, .poll = mptcp_poll, .ioctl = inet6_ioctl, .gettstamp = sock_gettstamp, .listen = mptcp_listen, .shutdown = inet_shutdown, .setsockopt = sock_common_setsockopt, .getsockopt = sock_common_getsockopt, .sendmsg = inet6_sendmsg, .recvmsg = inet6_recvmsg, .mmap = sock_no_mmap, .sendpage = inet_sendpage, #ifdef CONFIG_COMPAT .compat_ioctl = inet6_compat_ioctl, #endif }; static struct proto mptcp_v6_prot; static void mptcp_v6_destroy(struct sock *sk) { mptcp_destroy(sk); inet6_destroy_sock(sk); } static struct inet_protosw mptcp_v6_protosw = { .type = SOCK_STREAM, .protocol = IPPROTO_MPTCP, .prot = &mptcp_v6_prot, .ops = &mptcp_v6_stream_ops, .flags = INET_PROTOSW_ICSK, }; int __init mptcp_proto_v6_init(void) { int err; mptcp_v6_prot = mptcp_prot; strcpy(mptcp_v6_prot.name, "MPTCPv6"); mptcp_v6_prot.slab = NULL; mptcp_v6_prot.destroy = mptcp_v6_destroy; mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock); err = proto_register(&mptcp_v6_prot, 1); if (err) return err; err = inet6_register_protosw(&mptcp_v6_protosw); if (err) proto_unregister(&mptcp_v6_prot); return err; } #endif