| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Paolo Abeni | 10561 | 54.18% | 205 | 49.52% |
| Florian Westphal | 3210 | 16.47% | 55 | 13.29% |
| Peter Krystad | 1769 | 9.08% | 10 | 2.42% |
| Mat Martineau | 1583 | 8.12% | 13 | 3.14% |
| Geliang Tang | 1197 | 6.14% | 37 | 8.94% |
| Davide Caratti | 451 | 2.31% | 6 | 1.45% |
| Eric Dumazet | 128 | 0.66% | 18 | 4.35% |
| Matthieu Baerts | 107 | 0.55% | 9 | 2.17% |
| Menglong Dong | 91 | 0.47% | 3 | 0.72% |
| Linus Torvalds (pre-git) | 78 | 0.40% | 13 | 3.14% |
| Dmytro Shytyi | 57 | 0.29% | 2 | 0.48% |
| Yonglong Li | 50 | 0.26% | 3 | 0.72% |
| Arnaldo Carvalho de Melo | 34 | 0.17% | 7 | 1.69% |
| Benjamin Hesmans | 30 | 0.15% | 1 | 0.24% |
| David S. Miller | 16 | 0.08% | 3 | 0.72% |
| Kuniyuki Iwashima | 16 | 0.08% | 4 | 0.97% |
| Linus Torvalds | 14 | 0.07% | 1 | 0.24% |
| Jens Axboe | 11 | 0.06% | 1 | 0.24% |
| Rusty Russell | 11 | 0.06% | 1 | 0.24% |
| Kishen Maloor | 11 | 0.06% | 2 | 0.48% |
| Breno Leitão | 10 | 0.05% | 1 | 0.24% |
| Jason Xing | 10 | 0.05% | 2 | 0.48% |
| Hideaki Yoshifuji / 吉藤英明 | 7 | 0.04% | 3 | 0.72% |
| Joe Perches | 6 | 0.03% | 1 | 0.24% |
| Andi Kleen | 6 | 0.03% | 1 | 0.24% |
| Octavian Purdila | 5 | 0.03% | 1 | 0.24% |
| Christoph Hellwig | 5 | 0.03% | 2 | 0.48% |
| Oliver Hartkopp | 3 | 0.02% | 1 | 0.24% |
| Christoph Paasch | 3 | 0.02% | 1 | 0.24% |
| Dan Carpenter | 3 | 0.02% | 1 | 0.24% |
| Jiri Benc | 3 | 0.02% | 1 | 0.24% |
| Ilpo Järvinen | 2 | 0.01% | 1 | 0.24% |
| Gustavo A. R. Silva | 2 | 0.01% | 1 | 0.24% |
| Jakub Kiciński | 1 | 0.01% | 1 | 0.24% |
| Stephen Hemminger | 1 | 0.01% | 1 | 0.24% |
| Daniel Lezcano | 1 | 0.01% | 1 | 0.24% |
| Total | 19493 | 414 |
// 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 <linux/sched/signal.h> #include <linux/atomic.h> #include <net/sock.h> #include <net/inet_common.h> #include <net/inet_hashtables.h> #include <net/protocol.h> #include <net/tcp_states.h> #if IS_ENABLED(CONFIG_MPTCP_IPV6) #include <net/transp_v6.h> #endif #include <net/mptcp.h> #include <net/hotdata.h> #include <net/xfrm.h> #include <asm/ioctls.h> #include "protocol.h" #include "mib.h" #define CREATE_TRACE_POINTS #include <trace/events/mptcp.h> #if IS_ENABLED(CONFIG_MPTCP_IPV6) struct mptcp6_sock { struct mptcp_sock msk; struct ipv6_pinfo np; }; #endif enum { MPTCP_CMSG_TS = BIT(0), MPTCP_CMSG_INQ = BIT(1), }; static struct percpu_counter mptcp_sockets_allocated ____cacheline_aligned_in_smp; 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; /* 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 const struct proto_ops *mptcp_fallback_tcp_ops(const struct sock *sk) { #if IS_ENABLED(CONFIG_MPTCP_IPV6) if (sk->sk_prot == &tcpv6_prot) return &inet6_stream_ops; #endif WARN_ON_ONCE(sk->sk_prot != &tcp_prot); return &inet_stream_ops; } 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, sk->sk_family, &ssock); if (err) return err; msk->scaling_ratio = tcp_sk(ssock->sk)->scaling_ratio; WRITE_ONCE(msk->first, ssock->sk); subflow = mptcp_subflow_ctx(ssock->sk); list_add(&subflow->node, &msk->conn_list); sock_hold(ssock->sk); subflow->request_mptcp = 1; subflow->subflow_id = msk->subflow_id++; /* This is the first subflow, always with id 0 */ WRITE_ONCE(subflow->local_id, 0); mptcp_sock_graft(msk->first, sk->sk_socket); iput(SOCK_INODE(ssock)); return 0; } /* If the MPC handshake is not started, returns the first subflow, * eventually allocating it. */ struct sock *__mptcp_nmpc_sk(struct mptcp_sock *msk) { struct sock *sk = (struct sock *)msk; int ret; if (!((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) return ERR_PTR(-EINVAL); if (!msk->first) { ret = __mptcp_socket_create(msk); if (ret) return ERR_PTR(ret); } return msk->first; } static void mptcp_drop(struct sock *sk, struct sk_buff *skb) { sk_drops_add(sk, skb); __kfree_skb(skb); } static void mptcp_rmem_fwd_alloc_add(struct sock *sk, int size) { WRITE_ONCE(mptcp_sk(sk)->rmem_fwd_alloc, mptcp_sk(sk)->rmem_fwd_alloc + size); } static void mptcp_rmem_charge(struct sock *sk, int size) { mptcp_rmem_fwd_alloc_add(sk, -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\n", 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; /* note the fwd memory can reach a negative value after accounting * for the delta, but the later skb free will restore a non * negative one */ atomic_add(delta, &sk->sk_rmem_alloc); mptcp_rmem_charge(sk, delta); kfree_skb_partial(from, fragstolen); 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 >>= PAGE_SHIFT; mptcp_rmem_charge(sk, amount << PAGE_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; mptcp_rmem_fwd_alloc_add(sk, 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 >= PAGE_SIZE)) __mptcp_rmem_reclaim(sk, reclaimable); } 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); } 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 = atomic64_read(&msk->rcv_wnd_sent); pr_debug("msk=%p seq=%llx limit=%llx empty=%d\n", 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)atomic64_read(&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; size -= msk->rmem_fwd_alloc; amt = sk_mem_pages(size); amount = amt << PAGE_SHIFT; if (!__sk_mem_raise_allocated(sk, size, amt, SK_MEM_RECV)) return false; mptcp_rmem_fwd_alloc_add(sk, 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)) { MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED); 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 */ msk->bytes_received += copy_len; 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_rtx_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); } /* called under the msk socket lock */ static bool mptcp_pending_data_fin_ack(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); return ((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: mptcp_set_state(sk, TCP_FIN_WAIT2); break; case TCP_CLOSING: case TCP_LAST_ACK: mptcp_set_state(sk, TCP_CLOSE); break; } mptcp_close_wake_up(sk); } } /* can be called with no lock acquired */ 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 << inet_sk_state_load(sk)) & (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) { u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq); if (READ_ONCE(msk->ack_seq) == rcv_data_fin_seq) { if (seq) *seq = rcv_data_fin_seq; return true; } } return false; } static void mptcp_set_datafin_timeout(struct sock *sk) { struct inet_connection_sock *icsk = inet_csk(sk); u32 retransmits; retransmits = min_t(u32, icsk->icsk_retransmits, ilog2(TCP_RTO_MAX / TCP_RTO_MIN)); mptcp_sk(sk)->timer_ival = TCP_RTO_MIN << 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 inline 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) { if (tcp_can_send_ack(ssk)) tcp_send_ack(ssk); } static void mptcp_subflow_send_ack(struct sock *ssk) { bool slow; slow = lock_sock_fast(ssk); __mptcp_subflow_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; /* 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); WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | RCV_SHUTDOWN); smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ switch (sk->sk_state) { case TCP_ESTABLISHED: mptcp_set_state(sk, TCP_CLOSE_WAIT); break; case TCP_FIN_WAIT1: mptcp_set_state(sk, TCP_CLOSING); break; case TCP_FIN_WAIT2: mptcp_set_state(sk, TCP_CLOSE); break; default: /* Other states not expected */ WARN_ON_ONCE(1); break; } ret = true; if (!__mptcp_check_fallback(msk)) 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\n", 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) { /* With racing move_skbs_to_msk() and __mptcp_move_skbs(), * a different CPU can have already processed the pending * data, stop here or we can enter an infinite loop */ if (!moved) done = true; break; } if (__mptcp_check_fallback(msk)) { /* Under fallback skbs have no MPTCP extension and TCP could * collapse them between the dummy map creation and the * current dequeue. Be sure to adjust the map 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); if (moved > 0) msk->last_data_recv = tcp_jiffies32; *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\n", 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\n", MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq, delta); MPTCP_SKB_CB(skb)->offset += delta; MPTCP_SKB_CB(skb)->map_seq += delta; __skb_queue_tail(&sk->sk_receive_queue, skb); } msk->bytes_received += end_seq - msk->ack_seq; WRITE_ONCE(msk->ack_seq, end_seq); moved = true; } return moved; } static bool __mptcp_subflow_error_report(struct sock *sk, struct sock *ssk) { int err = sock_error(ssk); int ssk_state; if (!err) return false; /* only propagate errors on fallen-back sockets or * on MPC connect */ if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(mptcp_sk(sk))) return false; /* We need to propagate only transition to CLOSE state. * Orphaned socket will see such state change via * subflow_sched_work_if_closed() and that path will properly * destroy the msk as needed. */ ssk_state = inet_sk_state_load(ssk); if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD)) mptcp_set_state(sk, ssk_state); WRITE_ONCE(sk->sk_err, -err); /* This barrier is coupled with smp_rmb() in mptcp_poll() */ smp_wmb(); sk_error_report(sk); return true; } void __mptcp_error_report(struct sock *sk) { struct mptcp_subflow_context *subflow; struct mptcp_sock *msk = mptcp_sk(sk); mptcp_for_each_subflow(msk, subflow) if (__mptcp_subflow_error_report(sk, mptcp_subflow_tcp_sock(subflow))) break; } /* 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->cb_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) return; /* Wake-up the reader only for in-sequence data */ mptcp_data_lock(sk); if (move_skbs_to_msk(msk, ssk) && mptcp_epollin_ready(sk)) sk->sk_data_ready(sk); mptcp_data_unlock(sk); } static void mptcp_subflow_joined(struct mptcp_sock *msk, struct sock *ssk) { mptcp_subflow_ctx(ssk)->map_seq = READ_ONCE(msk->ack_seq); WRITE_ONCE(msk->allow_infinite_fallback, false); mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC); } static bool __mptcp_finish_join(struct mptcp_sock *msk, struct sock *ssk) { struct sock *sk = (struct sock *)msk; if (sk->sk_state != TCP_ESTABLISHED) return false; /* attach to msk socket only after we are sure we will deal with it * at close time */ if (sk->sk_socket && !ssk->sk_socket) mptcp_sock_graft(ssk, sk->sk_socket); mptcp_subflow_ctx(ssk)->subflow_id = msk->subflow_id++; mptcp_sockopt_sync_locked(msk, ssk); mptcp_subflow_joined(msk, ssk); mptcp_stop_tout_timer(sk); __mptcp_propagate_sndbuf(sk, ssk); return true; } static void __mptcp_flush_join_list(struct sock *sk, struct list_head *join_list) { struct mptcp_subflow_context *tmp, *subflow; struct mptcp_sock *msk = mptcp_sk(sk); list_for_each_entry_safe(subflow, tmp, join_list, node) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); bool slow = lock_sock_fast(ssk); list_move_tail(&subflow->node, &msk->conn_list); if (!__mptcp_finish_join(msk, ssk)) mptcp_subflow_reset(ssk); unlock_sock_fast(ssk, slow); } } static bool mptcp_rtx_timer_pending(struct sock *sk) { return timer_pending(&inet_csk(sk)->icsk_retransmit_timer); } static void mptcp_reset_rtx_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; } static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk) { struct mptcp_subflow_context *subflow; msk_owned_by_me(msk); 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 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); } /* called under both the msk socket lock and the data lock */ static void __mptcp_clean_una(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); struct mptcp_data_frag *dtmp, *dfrag; u64 snd_una; 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); } 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); } /* all retransmitted data acked, recovery completed */ if (unlikely(msk->recovery) && after64(msk->snd_una, msk->recovery_snd_nxt)) msk->recovery = false; out: if (snd_una == msk->snd_nxt && snd_una == msk->write_seq) { if (mptcp_rtx_timer_pending(sk) && !mptcp_data_fin_enabled(msk)) mptcp_stop_rtx_timer(sk); } else { mptcp_reset_rtx_timer(sk); } if (mptcp_pending_data_fin_ack(sk)) mptcp_schedule_work(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; 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; } __mptcp_sync_sndbuf(sk); } /* 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(const struct mptcp_sock *msk, struct sock *ssk, u64 data_seq, int avail_size) { u64 window_end = mptcp_wnd_end(msk); u64 mptcp_snd_wnd; if (__mptcp_check_fallback(msk)) return avail_size; mptcp_snd_wnd = window_end - data_seq; avail_size = min_t(unsigned int, mptcp_snd_wnd, avail_size); if (unlikely(tcp_sk(ssk)->snd_wnd < mptcp_snd_wnd)) { tcp_sk(ssk)->snd_wnd = min_t(u64, U32_MAX, mptcp_snd_wnd); MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_SNDWNDSHARED); } 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; } tcp_skb_tsorted_anchor_cleanup(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; 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 void mptcp_update_infinite_map(struct mptcp_sock *msk, struct sock *ssk, struct mptcp_ext *mpext) { if (!mpext) return; mpext->infinite_map = 1; mpext->data_len = 0; MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPTX); mptcp_subflow_ctx(ssk)->send_infinite_map = 0; pr_fallback(msk); mptcp_do_fallback(ssk); } #define MPTCP_MAX_GSO_SIZE (GSO_LEGACY_MAX_SIZE - (MAX_TCP_HEADER + 1)) 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\n", 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; if (unlikely(!__tcp_can_send(ssk))) return -EAGAIN; /* compute send limit */ if (unlikely(ssk->sk_gso_max_size > MPTCP_MAX_GSO_SIZE)) ssk->sk_gso_max_size = MPTCP_MAX_GSO_SIZE; 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 = mptcp_get_ext(skb); if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) { TCP_SKB_CB(skb)->eor = 1; tcp_mark_push(tcp_sk(ssk), skb); goto alloc_skb; } i = skb_shinfo(skb)->nr_frags; can_coalesce = skb_can_coalesce(skb, i, dfrag->page, offset); if (!can_coalesce && i >= READ_ONCE(net_hotdata.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 = mptcp_get_ext(skb); } /* Zero window and all data acked? Probe. */ copy = mptcp_check_allowed_size(msk, ssk, data_seq, copy); if (copy == 0) { u64 snd_una = READ_ONCE(msk->snd_una); if (snd_una != msk->snd_nxt || tcp_write_queue_tail(ssk)) { tcp_remove_empty_skb(ssk); return 0; } zero_window_probe = true; data_seq = snd_una - 1; copy = 1; } 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; 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\n", 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); if (mptcp_subflow_ctx(ssk)->send_infinite_map) mptcp_update_infinite_map(msk, ssk, mpext); trace_mptcp_sendmsg_frag(mpext); 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 linger_time; }; 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); } #define SSK_MODE_ACTIVE 0 #define SSK_MODE_BACKUP 1 #define SSK_MODE_MAX 2 /* implement the mptcp packet scheduler; * returns the subflow that will transmit the next DSS * additionally updates the rtx timeout */ struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk) { struct subflow_send_info send_info[SSK_MODE_MAX]; struct mptcp_subflow_context *subflow; struct sock *sk = (struct sock *)msk; u32 pace, burst, wmem; int i, nr_active = 0; struct sock *ssk; u64 linger_time; long tout = 0; /* pick the subflow with the lower wmem/wspace ratio */ for (i = 0; i < SSK_MODE_MAX; ++i) { send_info[i].ssk = NULL; send_info[i].linger_time = -1; } mptcp_for_each_subflow(msk, subflow) { bool backup = subflow->backup || subflow->request_bkup; 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 += !backup; pace = subflow->avg_pacing_rate; if (unlikely(!pace)) { /* init pacing rate from socket */ subflow->avg_pacing_rate = READ_ONCE(ssk->sk_pacing_rate); pace = subflow->avg_pacing_rate; if (!pace) continue; } linger_time = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32, pace); if (linger_time < send_info[backup].linger_time) { send_info[backup].ssk = ssk; send_info[backup].linger_time = linger_time; } } __mptcp_set_timeout(sk, tout); /* pick the best backup if no other subflow is active */ if (!nr_active) send_info[SSK_MODE_ACTIVE].ssk = send_info[SSK_MODE_BACKUP].ssk; /* According to the blest algorithm, to avoid HoL blocking for the * faster flow, we need to: * - estimate the faster flow linger time * - use the above to estimate the amount of byte transferred * by the faster flow * - check that the amount of queued data is greter than the above, * otherwise do not use the picked, slower, subflow * We select the subflow with the shorter estimated time to flush * the queued mem, which basically ensure the above. We just need * to check that subflow has a non empty cwin. */ ssk = send_info[SSK_MODE_ACTIVE].ssk; if (!ssk || !sk_stream_memory_free(ssk)) return NULL; burst = min_t(int, MPTCP_SEND_BURST_SIZE, mptcp_wnd_end(msk) - msk->snd_nxt); wmem = READ_ONCE(ssk->sk_wmem_queued); if (!burst) return ssk; subflow = mptcp_subflow_ctx(ssk); subflow->avg_pacing_rate = div_u64((u64)subflow->avg_pacing_rate * wmem + READ_ONCE(ssk->sk_pacing_rate) * burst, burst + wmem); msk->snd_burst = burst; return ssk; } 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->bytes_sent += snd_nxt_new - msk->snd_nxt; WRITE_ONCE(msk->snd_nxt, snd_nxt_new); } } void mptcp_check_and_set_pending(struct sock *sk) { if (mptcp_send_head(sk)) { mptcp_data_lock(sk); mptcp_sk(sk)->cb_flags |= BIT(MPTCP_PUSH_PENDING); mptcp_data_unlock(sk); } } static int __subflow_push_pending(struct sock *sk, struct sock *ssk, struct mptcp_sendmsg_info *info) { struct mptcp_sock *msk = mptcp_sk(sk); struct mptcp_data_frag *dfrag; int len, copied = 0, err = 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; ret = mptcp_sendmsg_frag(sk, ssk, dfrag, info); if (ret <= 0) { err = copied ? : ret; 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)); if (msk->snd_burst <= 0 || !sk_stream_memory_free(ssk) || !mptcp_subflow_active(mptcp_subflow_ctx(ssk))) { err = copied; goto out; } mptcp_set_timeout(sk); } err = copied; out: if (err > 0) msk->last_data_sent = tcp_jiffies32; return err; } 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, }; bool do_check_data_fin = false; int push_count = 1; while (mptcp_send_head(sk) && (push_count > 0)) { struct mptcp_subflow_context *subflow; int ret = 0; if (mptcp_sched_get_send(msk)) break; push_count = 0; mptcp_for_each_subflow(msk, subflow) { if (READ_ONCE(subflow->scheduled)) { mptcp_subflow_set_scheduled(subflow, false); prev_ssk = ssk; ssk = mptcp_subflow_tcp_sock(subflow); if (ssk != prev_ssk) { /* First check. If the ssk has changed since * the last round, release prev_ssk */ if (prev_ssk) mptcp_push_release(prev_ssk, &info); /* Need to lock the new subflow only if different * from the previous one, otherwise we are still * helding the relevant lock */ lock_sock(ssk); } push_count++; ret = __subflow_push_pending(sk, ssk, &info); if (ret <= 0) { if (ret != -EAGAIN || (1 << ssk->sk_state) & (TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSE)) push_count--; continue; } do_check_data_fin = true; } } } /* at this point we held the socket lock for the last subflow we used */ if (ssk) mptcp_push_release(ssk, &info); /* ensure the rtx timer is running */ if (!mptcp_rtx_timer_pending(sk)) mptcp_reset_rtx_timer(sk); if (do_check_data_fin) mptcp_check_send_data_fin(sk); } static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk, bool first) { struct mptcp_sock *msk = mptcp_sk(sk); struct mptcp_sendmsg_info info = { .data_lock_held = true, }; bool keep_pushing = true; struct sock *xmit_ssk; int copied = 0; info.flags = 0; while (mptcp_send_head(sk) && keep_pushing) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); int ret = 0; /* check for a different subflow usage only after * spooling the first chunk of data */ if (first) { mptcp_subflow_set_scheduled(subflow, false); ret = __subflow_push_pending(sk, ssk, &info); first = false; if (ret <= 0) break; copied += ret; continue; } if (mptcp_sched_get_send(msk)) goto out; if (READ_ONCE(subflow->scheduled)) { mptcp_subflow_set_scheduled(subflow, false); ret = __subflow_push_pending(sk, ssk, &info); if (ret <= 0) keep_pushing = false; copied += ret; } mptcp_for_each_subflow(msk, subflow) { if (READ_ONCE(subflow->scheduled)) { xmit_ssk = mptcp_subflow_tcp_sock(subflow); if (xmit_ssk != ssk) { mptcp_subflow_delegate(subflow, MPTCP_DELEGATE_SEND); keep_pushing = false; } } } } 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_rtx_timer_pending(sk)) mptcp_reset_rtx_timer(sk); if (msk->snd_data_fin_enable && msk->snd_nxt + 1 == msk->write_seq) mptcp_schedule_work(sk); } } static int mptcp_disconnect(struct sock *sk, int flags); static int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, size_t len, int *copied_syn) { unsigned int saved_flags = msg->msg_flags; struct mptcp_sock *msk = mptcp_sk(sk); struct sock *ssk; int ret; /* on flags based fastopen the mptcp is supposed to create the * first subflow right now. Otherwise we are in the defer_connect * path, and the first subflow must be already present. * Since the defer_connect flag is cleared after the first succsful * fastopen attempt, no need to check for additional subflow status. */ if (msg->msg_flags & MSG_FASTOPEN) { ssk = __mptcp_nmpc_sk(msk); if (IS_ERR(ssk)) return PTR_ERR(ssk); } if (!msk->first) return -EINVAL; ssk = msk->first; lock_sock(ssk); msg->msg_flags |= MSG_DONTWAIT; msk->fastopening = 1; ret = tcp_sendmsg_fastopen(ssk, msg, copied_syn, len, NULL); msk->fastopening = 0; msg->msg_flags = saved_flags; release_sock(ssk); /* do the blocking bits of inet_stream_connect outside the ssk socket lock */ if (ret == -EINPROGRESS && !(msg->msg_flags & MSG_DONTWAIT)) { ret = __inet_stream_connect(sk->sk_socket, msg->msg_name, msg->msg_namelen, msg->msg_flags, 1); /* Keep the same behaviour of plain TCP: zero the copied bytes in * case of any error, except timeout or signal */ if (ret && ret != -EINPROGRESS && ret != -ERESTARTSYS && ret != -EINTR) *copied_syn = 0; } else if (ret && ret != -EINPROGRESS) { /* The disconnect() op called by tcp_sendmsg_fastopen()/ * __inet_stream_connect() can fail, due to looking check, * see mptcp_disconnect(). * Attempt it again outside the problematic scope. */ if (!mptcp_disconnect(sk, 0)) sk->sk_socket->state = SS_UNCONNECTED; } inet_clear_bit(DEFER_CONNECT, sk); return ret; } static int do_copy_data_nocache(struct sock *sk, int copy, struct iov_iter *from, char *to) { if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) { if (!copy_from_iter_full_nocache(to, copy, from)) return -EFAULT; } else if (!copy_from_iter_full(to, copy, from)) { return -EFAULT; } return 0; } /* open-code sk_stream_memory_free() plus sent limit computation to * avoid indirect calls in fast-path. * Called under the msk socket lock, so we can avoid a bunch of ONCE * annotations. */ static u32 mptcp_send_limit(const struct sock *sk) { const struct mptcp_sock *msk = mptcp_sk(sk); u32 limit, not_sent; if (sk->sk_wmem_queued >= READ_ONCE(sk->sk_sndbuf)) return 0; limit = mptcp_notsent_lowat(sk); if (limit == UINT_MAX) return UINT_MAX; not_sent = msk->write_seq - msk->snd_nxt; if (not_sent >= limit) return 0; return limit - not_sent; } 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; /* silently ignore everything else */ msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_FASTOPEN; lock_sock(sk); if (unlikely(inet_test_bit(DEFER_CONNECT, sk) || msg->msg_flags & MSG_FASTOPEN)) { int copied_syn = 0; ret = mptcp_sendmsg_fastopen(sk, msg, len, &copied_syn); copied += copied_syn; if (ret == -EINPROGRESS && copied_syn > 0) goto out; else if (ret) goto do_error; } 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 do_error; } ret = -EPIPE; if (unlikely(sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))) goto do_error; 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; u32 copy_limit; /* ensure fitting the notsent_lowat() constraint */ copy_limit = mptcp_send_limit(sk); if (!copy_limit) goto wait_for_memory; /* 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 (!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)); psize = min_t(size_t, psize, copy_limit); total_ts = psize + frag_truesize; if (!sk_wmem_schedule(sk, total_ts)) goto wait_for_memory; ret = do_copy_data_nocache(sk, psize, &msg->msg_iter, page_address(dfrag->page) + offset); if (ret) goto do_error; /* data successfully copied into the write queue */ sk_forward_alloc_add(sk, -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\n", msk, dfrag->data_seq, dfrag->data_len, dfrag->already_sent, !dfrag_collapsed); continue; wait_for_memory: set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); __mptcp_push_pending(sk, msg->msg_flags); ret = sk_stream_wait_memory(sk, &timeo); if (ret) goto do_error; } if (copied) __mptcp_push_pending(sk, msg->msg_flags); out: release_sock(sk); return copied; do_error: if (copied) goto out; copied = sk_stream_error(sk, msg->msg_flags, ret); goto out; } 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; MPTCP_SKB_CB(skb)->map_seq += count; msk->bytes_consumed += 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); msk->bytes_consumed += count; } 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; u8 scaling_ratio = U8_MAX; u32 time, advmss = 1; u64 rtt_us, mstamp; msk_owned_by_me(msk); if (copied <= 0) return; if (!msk->rcvspace_init) mptcp_rcv_space_init(msk, msk->first); 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); scaling_ratio = min(tp->scaling_ratio, scaling_ratio); } msk->rcvq_space.rtt_us = rtt_us; msk->scaling_ratio = scaling_ratio; if (time < (rtt_us >> 3) || rtt_us == 0) return; if (msk->rcvq_space.copied <= msk->rcvq_space.space) goto new_measure; if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf) && !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { u64 rcvwin, grow; int rcvbuf; 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); rcvbuf = min_t(u64, mptcp_space_from_win(sk, rcvwin), READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2])); if (rcvbuf > sk->sk_rcvbuf) { u32 window_clamp; window_clamp = mptcp_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); WRITE_ONCE(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; 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 unsigned int mptcp_inq_hint(const struct sock *sk) { const struct mptcp_sock *msk = mptcp_sk(sk); const struct sk_buff *skb; skb = skb_peek(&msk->receive_queue); if (skb) { u64 hint_val = READ_ONCE(msk->ack_seq) - MPTCP_SKB_CB(skb)->map_seq; if (hint_val >= INT_MAX) return INT_MAX; return (unsigned int)hint_val; } if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN)) return 1; return 0; } static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 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, flags & MSG_DONTWAIT); len = min_t(size_t, len, INT_MAX); target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); if (unlikely(msk->recvmsg_inq)) cmsg_flags = MPTCP_CMSG_INQ; 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 MPTCP 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 (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\n", 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); if (cmsg_flags & MPTCP_CMSG_INQ) { unsigned int inq = mptcp_inq_hint(sk); put_cmsg(msg, SOL_TCP, TCP_CM_INQ, sizeof(inq), &inq); } } pr_debug("msk=%p rx queue empty=%d:%d copied=%d\n", 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->cb_flags); } bh_unlock_sock(sk); sock_put(sk); } static void mptcp_tout_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. */ 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; 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 || subflow->request_bkup) { 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; } 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(msk)) 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; } /* flags for __mptcp_close_ssk() */ #define MPTCP_CF_PUSH BIT(1) #define MPTCP_CF_FASTCLOSE BIT(2) /* be sure to send a reset only if the caller asked for it, also * clean completely the subflow status when the subflow reaches * TCP_CLOSE state */ static void __mptcp_subflow_disconnect(struct sock *ssk, struct mptcp_subflow_context *subflow, unsigned int flags) { if (((1 << ssk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) || (flags & MPTCP_CF_FASTCLOSE)) { /* The MPTCP code never wait on the subflow sockets, TCP-level * disconnect should never fail */ WARN_ON_ONCE(tcp_disconnect(ssk, 0)); mptcp_subflow_ctx_reset(subflow); } else { tcp_shutdown(ssk, SEND_SHUTDOWN); } } /* 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, unsigned int flags) { struct mptcp_sock *msk = mptcp_sk(sk); bool dispose_it, need_push = false; /* If the first subflow moved to a close state before accept, e.g. due * to an incoming reset or listener shutdown, the subflow socket is * already deleted by inet_child_forget() and the mptcp socket can't * survive too. */ if (msk->in_accept_queue && msk->first == ssk && (sock_flag(sk, SOCK_DEAD) || sock_flag(ssk, SOCK_DEAD))) { /* ensure later check in mptcp_worker() will dispose the msk */ sock_set_flag(sk, SOCK_DEAD); mptcp_set_close_tout(sk, tcp_jiffies32 - (mptcp_close_timeout(sk) + 1)); lock_sock_nested(ssk, SINGLE_DEPTH_NESTING); mptcp_subflow_drop_ctx(ssk); goto out_release; } dispose_it = msk->free_first || ssk != msk->first; if (dispose_it) list_del(&subflow->node); lock_sock_nested(ssk, SINGLE_DEPTH_NESTING); if ((flags & MPTCP_CF_FASTCLOSE) && !__mptcp_check_fallback(msk)) { /* be sure to force the tcp_close path * to generate the egress reset */ ssk->sk_lingertime = 0; sock_set_flag(ssk, SOCK_LINGER); subflow->send_fastclose = 1; } need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk); if (!dispose_it) { __mptcp_subflow_disconnect(ssk, subflow, flags); release_sock(ssk); goto out; } 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) { WARN_ON_ONCE(!sock_flag(ssk, SOCK_DEAD)); 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); } out_release: __mptcp_subflow_error_report(sk, ssk); release_sock(ssk); sock_put(ssk); if (ssk == msk->first) WRITE_ONCE(msk->first, NULL); out: __mptcp_sync_sndbuf(sk); if (need_push) __mptcp_push_pending(sk, 0); /* Catch every 'all subflows closed' scenario, including peers silently * closing them, e.g. due to timeout. * For established sockets, allow an additional timeout before closing, * as the protocol can still create more subflows. */ if (list_is_singular(&msk->conn_list) && msk->first && inet_sk_state_load(msk->first) == TCP_CLOSE) { if (sk->sk_state != TCP_ESTABLISHED || msk->in_accept_queue || sock_flag(sk, SOCK_DEAD)) { mptcp_set_state(sk, TCP_CLOSE); mptcp_close_wake_up(sk); } else { mptcp_start_tout_timer(sk); } } } void mptcp_close_ssk(struct sock *sk, struct sock *ssk, struct mptcp_subflow_context *subflow) { /* The first subflow can already be closed and still in the list */ if (subflow->close_event_done) return; subflow->close_event_done = true; if (sk->sk_state == TCP_ESTABLISHED) mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL); /* subflow aborted before reaching the fully_established status * attempt the creation of the next subflow */ mptcp_pm_subflow_check_next(mptcp_sk(sk), subflow); __mptcp_close_ssk(sk, ssk, subflow, MPTCP_CF_PUSH); } static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu) { return 0; } static void __mptcp_close_subflow(struct sock *sk) { struct mptcp_subflow_context *subflow, *tmp; struct mptcp_sock *msk = mptcp_sk(sk); might_sleep(); mptcp_for_each_subflow_safe(msk, subflow, tmp) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); int ssk_state = inet_sk_state_load(ssk); if (ssk_state != TCP_CLOSE && (ssk_state != TCP_CLOSE_WAIT || inet_sk_state_load(sk) != TCP_ESTABLISHED)) 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(sk, ssk, subflow); } } static bool mptcp_close_tout_expired(const struct sock *sk) { if (!inet_csk(sk)->icsk_mtup.probe_timestamp || sk->sk_state == TCP_CLOSE) return false; return time_after32(tcp_jiffies32, inet_csk(sk)->icsk_mtup.probe_timestamp + mptcp_close_timeout(sk)); } static void mptcp_check_fastclose(struct mptcp_sock *msk) { struct mptcp_subflow_context *subflow, *tmp; struct sock *sk = (struct sock *)msk; if (likely(!READ_ONCE(msk->rcv_fastclose))) return; mptcp_token_destroy(msk); mptcp_for_each_subflow_safe(msk, subflow, tmp) { struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); bool slow; slow = lock_sock_fast(tcp_sk); if (tcp_sk->sk_state != TCP_CLOSE) { mptcp_send_active_reset_reason(tcp_sk); tcp_set_state(tcp_sk, TCP_CLOSE); } unlock_sock_fast(tcp_sk, slow); } /* Mirror the tcp_reset() error propagation */ switch (sk->sk_state) { case TCP_SYN_SENT: WRITE_ONCE(sk->sk_err, ECONNREFUSED); break; case TCP_CLOSE_WAIT: WRITE_ONCE(sk->sk_err, EPIPE); break; case TCP_CLOSE: return; default: WRITE_ONCE(sk->sk_err, ECONNRESET); } mptcp_set_state(sk, TCP_CLOSE); WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK); smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags); /* the calling mptcp_worker will properly destroy the socket */ if (sock_flag(sk, SOCK_DEAD)) return; sk->sk_state_change(sk); sk_error_report(sk); } static void __mptcp_retrans(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); struct mptcp_subflow_context *subflow; struct mptcp_sendmsg_info info = {}; struct mptcp_data_frag *dfrag; struct sock *ssk; int ret, err; u16 len = 0; mptcp_clean_una_wakeup(sk); /* first check ssk: need to kick "stale" logic */ err = mptcp_sched_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 (err) goto reset_timer; mptcp_for_each_subflow(msk, subflow) { if (READ_ONCE(subflow->scheduled)) { u16 copied = 0; mptcp_subflow_set_scheduled(subflow, false); ssk = mptcp_subflow_tcp_sock(subflow); 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) { len = max(copied, len); tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, info.size_goal); WRITE_ONCE(msk->allow_infinite_fallback, false); } release_sock(ssk); } } msk->bytes_retrans += len; dfrag->already_sent = max(dfrag->already_sent, len); reset_timer: mptcp_check_and_set_pending(sk); if (!mptcp_rtx_timer_pending(sk)) mptcp_reset_rtx_timer(sk); } /* schedule the timeout timer for the relevant event: either close timeout * or mp_fail timeout. The close timeout takes precedence on the mp_fail one */ void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout) { struct sock *sk = (struct sock *)msk; unsigned long timeout, close_timeout; if (!fail_tout && !inet_csk(sk)->icsk_mtup.probe_timestamp) return; close_timeout = inet_csk(sk)->icsk_mtup.probe_timestamp - tcp_jiffies32 + jiffies + mptcp_close_timeout(sk); /* the close timeout takes precedence on the fail one, and here at least one of * them is active */ timeout = inet_csk(sk)->icsk_mtup.probe_timestamp ? close_timeout : fail_tout; sk_reset_timer(sk, &sk->sk_timer, timeout); } static void mptcp_mp_fail_no_response(struct mptcp_sock *msk) { struct sock *ssk = msk->first; bool slow; if (!ssk) return; pr_debug("MP_FAIL doesn't respond, reset the subflow\n"); slow = lock_sock_fast(ssk); mptcp_subflow_reset(ssk); WRITE_ONCE(mptcp_subflow_ctx(ssk)->fail_tout, 0); unlock_sock_fast(ssk, slow); } static void mptcp_do_fastclose(struct sock *sk) { struct mptcp_subflow_context *subflow, *tmp; struct mptcp_sock *msk = mptcp_sk(sk); mptcp_set_state(sk, TCP_CLOSE); mptcp_for_each_subflow_safe(msk, subflow, tmp) __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), subflow, MPTCP_CF_FASTCLOSE); } static void mptcp_worker(struct work_struct *work) { struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work); struct sock *sk = (struct sock *)msk; unsigned long fail_tout; int state; lock_sock(sk); state = sk->sk_state; if (unlikely((1 << state) & (TCPF_CLOSE | TCPF_LISTEN))) goto unlock; mptcp_check_fastclose(msk); mptcp_pm_nl_work(msk); mptcp_check_send_data_fin(sk); mptcp_check_data_fin_ack(sk); mptcp_check_data_fin(sk); if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags)) __mptcp_close_subflow(sk); if (mptcp_close_tout_expired(sk)) { mptcp_do_fastclose(sk); mptcp_close_wake_up(sk); } if (sock_flag(sk, SOCK_DEAD) && sk->sk_state == TCP_CLOSE) { __mptcp_destroy_sock(sk); goto unlock; } if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags)) __mptcp_retrans(sk); fail_tout = msk->first ? READ_ONCE(mptcp_subflow_ctx(msk->first)->fail_tout) : 0; if (fail_tout && time_after(jiffies, fail_tout)) mptcp_mp_fail_no_response(msk); unlock: release_sock(sk); sock_put(sk); } static void __mptcp_init_sock(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); 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; WRITE_ONCE(msk->rmem_fwd_alloc, 0); WRITE_ONCE(msk->rmem_released, 0); msk->timer_ival = TCP_RTO_MIN; msk->scaling_ratio = TCP_DEFAULT_SCALING_RATIO; WRITE_ONCE(msk->first, NULL); inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss; WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk))); WRITE_ONCE(msk->allow_infinite_fallback, true); msk->recovery = false; msk->subflow_id = 1; msk->last_data_sent = tcp_jiffies32; msk->last_data_recv = tcp_jiffies32; msk->last_ack_recv = tcp_jiffies32; 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_tout_timer, 0); } static void mptcp_ca_reset(struct sock *sk) { struct inet_connection_sock *icsk = inet_csk(sk); tcp_assign_congestion_control(sk); strscpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name, sizeof(mptcp_sk(sk)->ca_name)); /* no need to keep a reference to the ops, the name will suffice */ tcp_cleanup_congestion_control(sk); icsk->icsk_ca_ops = NULL; } static int mptcp_init_sock(struct sock *sk) { struct net *net = sock_net(sk); int ret; __mptcp_init_sock(sk); if (!mptcp_is_enabled(net)) return -ENOPROTOOPT; if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net)) return -ENOMEM; ret = mptcp_init_sched(mptcp_sk(sk), mptcp_sched_find(mptcp_get_scheduler(net))); if (ret) return ret; set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags); /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will * propagate the correct value */ mptcp_ca_reset(sk); sk_sockets_allocated_inc(sk); sk->sk_rcvbuf = READ_ONCE(net->ipv4.sysctl_tcp_rmem[1]); sk->sk_sndbuf = READ_ONCE(net->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); } 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: WARN_ON_ONCE(tcp_disconnect(ssk, O_NONBLOCK)); break; default: if (__mptcp_check_fallback(mptcp_sk(sk))) { pr_debug("Fallback\n"); ssk->sk_shutdown |= how; tcp_shutdown(ssk, how); /* simulate the data_fin ack reception to let the state * machine move forward */ WRITE_ONCE(mptcp_sk(sk)->snd_una, mptcp_sk(sk)->snd_nxt); mptcp_schedule_work(sk); } else { pr_debug("Sending DATA_FIN on subflow %p\n", ssk); tcp_send_ack(ssk); if (!mptcp_rtx_timer_pending(sk)) mptcp_reset_rtx_timer(sk); } break; } release_sock(ssk); } void mptcp_set_state(struct sock *sk, int state) { int oldstate = sk->sk_state; switch (state) { case TCP_ESTABLISHED: if (oldstate != TCP_ESTABLISHED) MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_CURRESTAB); break; case TCP_CLOSE_WAIT: /* Unlike TCP, MPTCP sk would not have the TCP_SYN_RECV state: * MPTCP "accepted" sockets will be created later on. So no * transition from TCP_SYN_RECV to TCP_CLOSE_WAIT. */ break; default: if (oldstate == TCP_ESTABLISHED || oldstate == TCP_CLOSE_WAIT) MPTCP_DEC_STATS(sock_net(sk), MPTCP_MIB_CURRESTAB); } inet_sk_state_store(sk, state); } 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; mptcp_set_state(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\n", 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); 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\n", 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_sock *msk = mptcp_sk(sk); pr_debug("msk=%p\n", msk); might_sleep(); mptcp_stop_rtx_timer(sk); sk_stop_timer(sk, &sk->sk_timer); msk->pm.status = 0; mptcp_release_sched(msk); sk->sk_prot->destroy(sk); WARN_ON_ONCE(READ_ONCE(msk->rmem_fwd_alloc)); WARN_ON_ONCE(msk->rmem_released); sk_stream_kill_queues(sk); xfrm_sk_free_policy(sk); sock_put(sk); } void __mptcp_unaccepted_force_close(struct sock *sk) { sock_set_flag(sk, SOCK_DEAD); mptcp_do_fastclose(sk); __mptcp_destroy_sock(sk); } static __poll_t mptcp_check_readable(struct sock *sk) { return mptcp_epollin_ready(sk) ? EPOLLIN | EPOLLRDNORM : 0; } static void mptcp_check_listen_stop(struct sock *sk) { struct sock *ssk; if (inet_sk_state_load(sk) != TCP_LISTEN) return; sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); ssk = mptcp_sk(sk)->first; if (WARN_ON_ONCE(!ssk || inet_sk_state_load(ssk) != TCP_LISTEN)) return; lock_sock_nested(ssk, SINGLE_DEPTH_NESTING); tcp_set_state(ssk, TCP_CLOSE); mptcp_subflow_queue_clean(sk, ssk); inet_csk_listen_stop(ssk); mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CLOSED); release_sock(ssk); } bool __mptcp_close(struct sock *sk, long timeout) { struct mptcp_subflow_context *subflow; struct mptcp_sock *msk = mptcp_sk(sk); bool do_cancel_work = false; int subflows_alive = 0; WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK); if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) { mptcp_check_listen_stop(sk); mptcp_set_state(sk, TCP_CLOSE); goto cleanup; } if (mptcp_data_avail(msk) || timeout < 0) { /* If the msk has read data, or the caller explicitly ask it, * do the MPTCP equivalent of TCP reset, aka MPTCP fastclose */ mptcp_do_fastclose(sk); timeout = 0; } else if (mptcp_close_state(sk)) { __mptcp_wr_shutdown(sk); } sk_stream_wait_close(sk, timeout); cleanup: /* orphan all the subflows */ mptcp_for_each_subflow(msk, subflow) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); bool slow = lock_sock_fast_nested(ssk); subflows_alive += ssk->sk_state != TCP_CLOSE; /* since the close timeout takes precedence on the fail one, * cancel the latter */ if (ssk == msk->first) subflow->fail_tout = 0; /* detach from the parent socket, but allow data_ready to * push incoming data into the mptcp stack, to properly ack it */ ssk->sk_socket = NULL; ssk->sk_wq = NULL; unlock_sock_fast(ssk, slow); } sock_orphan(sk); /* all the subflows are closed, only timeout can change the msk * state, let's not keep resources busy for no reasons */ if (subflows_alive == 0) mptcp_set_state(sk, TCP_CLOSE); sock_hold(sk); pr_debug("msk=%p state=%d\n", sk, sk->sk_state); if (msk->token) mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL); if (sk->sk_state == TCP_CLOSE) { __mptcp_destroy_sock(sk); do_cancel_work = true; } else { mptcp_start_tout_timer(sk); } return do_cancel_work; } static void mptcp_close(struct sock *sk, long timeout) { bool do_cancel_work; lock_sock(sk); do_cancel_work = __mptcp_close(sk, timeout); release_sock(sk); if (do_cancel_work) mptcp_cancel_work(sk); 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_sock *msk = mptcp_sk(sk); /* We are on the fastopen error path. We can't call straight into the * subflows cleanup code due to lock nesting (we are already under * msk->firstsocket lock). */ if (msk->fastopening) return -EBUSY; mptcp_check_listen_stop(sk); mptcp_set_state(sk, TCP_CLOSE); mptcp_stop_rtx_timer(sk); mptcp_stop_tout_timer(sk); if (msk->token) mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL); /* msk->subflow is still intact, the following will not free the first * subflow */ mptcp_destroy_common(msk, MPTCP_CF_FASTCLOSE); WRITE_ONCE(msk->flags, 0); msk->cb_flags = 0; msk->recovery = false; WRITE_ONCE(msk->can_ack, false); WRITE_ONCE(msk->fully_established, false); WRITE_ONCE(msk->rcv_data_fin, false); WRITE_ONCE(msk->snd_data_fin_enable, false); WRITE_ONCE(msk->rcv_fastclose, false); WRITE_ONCE(msk->use_64bit_ack, false); WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk))); mptcp_pm_data_reset(msk); mptcp_ca_reset(sk); msk->bytes_consumed = 0; msk->bytes_acked = 0; msk->bytes_received = 0; msk->bytes_sent = 0; msk->bytes_retrans = 0; msk->rcvspace_init = 0; WRITE_ONCE(sk->sk_shutdown, 0); sk_error_report(sk); 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); } static void mptcp_copy_ip6_options(struct sock *newsk, const struct sock *sk) { const struct ipv6_pinfo *np = inet6_sk(sk); struct ipv6_txoptions *opt; struct ipv6_pinfo *newnp; newnp = inet6_sk(newsk); rcu_read_lock(); opt = rcu_dereference(np->opt); if (opt) { opt = ipv6_dup_options(newsk, opt); if (!opt) net_warn_ratelimited("%s: Failed to copy ip6 options\n", __func__); } RCU_INIT_POINTER(newnp->opt, opt); rcu_read_unlock(); } #endif static void mptcp_copy_ip_options(struct sock *newsk, const struct sock *sk) { struct ip_options_rcu *inet_opt, *newopt = NULL; const struct inet_sock *inet = inet_sk(sk); struct inet_sock *newinet; newinet = inet_sk(newsk); rcu_read_lock(); inet_opt = rcu_dereference(inet->inet_opt); if (inet_opt) { newopt = sock_kmalloc(newsk, sizeof(*inet_opt) + inet_opt->opt.optlen, GFP_ATOMIC); if (newopt) memcpy(newopt, inet_opt, sizeof(*inet_opt) + inet_opt->opt.optlen); else net_warn_ratelimited("%s: Failed to copy ip options\n", __func__); } RCU_INIT_POINTER(newinet->inet_opt, newopt); rcu_read_unlock(); } struct sock *mptcp_sk_clone_init(const struct sock *sk, const struct mptcp_options_received *mp_opt, struct sock *ssk, 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_subflow_context *subflow; struct mptcp_sock *msk; 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); #if IS_ENABLED(CONFIG_MPTCP_IPV6) if (nsk->sk_family == AF_INET6) mptcp_copy_ip6_options(nsk, sk); else #endif mptcp_copy_ip_options(nsk, sk); msk = mptcp_sk(nsk); WRITE_ONCE(msk->local_key, subflow_req->local_key); WRITE_ONCE(msk->token, subflow_req->token); msk->in_accept_queue = 1; WRITE_ONCE(msk->fully_established, false); if (mp_opt->suboptions & OPTION_MPTCP_CSUMREQD) WRITE_ONCE(msk->csum_enabled, true); WRITE_ONCE(msk->write_seq, subflow_req->idsn + 1); WRITE_ONCE(msk->snd_nxt, msk->write_seq); WRITE_ONCE(msk->snd_una, msk->write_seq); WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd); msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq; mptcp_init_sched(msk, mptcp_sk(sk)->sched); /* passive msk is created after the first/MPC subflow */ msk->subflow_id = 2; sock_reset_flag(nsk, SOCK_RCU_FREE); security_inet_csk_clone(nsk, req); /* this can't race with mptcp_close(), as the msk is * not yet exposted to user-space */ mptcp_set_state(nsk, TCP_ESTABLISHED); /* The msk maintain a ref to each subflow in the connections list */ WRITE_ONCE(msk->first, ssk); subflow = mptcp_subflow_ctx(ssk); list_add(&subflow->node, &msk->conn_list); sock_hold(ssk); /* new mpc subflow takes ownership of the newly * created mptcp socket */ mptcp_token_accept(subflow_req, msk); /* set msk addresses early to ensure mptcp_pm_get_local_id() * uses the correct data */ mptcp_copy_inaddrs(nsk, ssk); __mptcp_propagate_sndbuf(nsk, ssk); mptcp_rcv_space_init(msk, ssk); if (mp_opt->suboptions & OPTION_MPTCP_MPC_ACK) __mptcp_subflow_fully_established(msk, subflow, mp_opt); bh_unlock_sock(nsk); /* note: the newly allocated socket refcount is 2 now */ return nsk; } void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk) { const struct tcp_sock *tp = tcp_sk(ssk); msk->rcvspace_init = 1; 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; } void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags) { struct mptcp_subflow_context *subflow, *tmp; struct sock *sk = (struct sock *)msk; __mptcp_clear_xmit(sk); /* join list will be eventually flushed (with rst) at sock lock release time */ mptcp_for_each_subflow_safe(msk, subflow, tmp) __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), subflow, flags); /* move to sk_receive_queue, sk_stream_kill_queues will purge it */ mptcp_data_lock(sk); 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); mptcp_data_unlock(sk); /* move all the rx fwd alloc into the sk_mem_reclaim_final in * inet_sock_destruct() will dispose it */ sk_forward_alloc_add(sk, msk->rmem_fwd_alloc); WRITE_ONCE(msk->rmem_fwd_alloc, 0); mptcp_token_destroy(msk); mptcp_pm_free_anno_list(msk); mptcp_free_local_addr_list(msk); } static void mptcp_destroy(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); /* allow the following to close even the initial subflow */ msk->free_first = 1; mptcp_destroy_common(msk, 0); 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)->cb_flags); } void __mptcp_check_push(struct sock *sk, struct sock *ssk) { if (!mptcp_send_head(sk)) return; if (!sock_owned_by_user(sk)) __mptcp_subflow_push_pending(sk, ssk, false); else __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags); } #define MPTCP_FLAGS_PROCESS_CTX_NEED (BIT(MPTCP_PUSH_PENDING) | \ BIT(MPTCP_RETRANSMIT) | \ BIT(MPTCP_FLUSH_JOIN_LIST)) /* processes deferred events and flush wmem */ static void mptcp_release_cb(struct sock *sk) __must_hold(&sk->sk_lock.slock) { struct mptcp_sock *msk = mptcp_sk(sk); for (;;) { unsigned long flags = (msk->cb_flags & MPTCP_FLAGS_PROCESS_CTX_NEED); struct list_head join_list; if (!flags) break; INIT_LIST_HEAD(&join_list); list_splice_init(&msk->join_list, &join_list); /* 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 */ msk->cb_flags &= ~flags; spin_unlock_bh(&sk->sk_lock.slock); if (flags & BIT(MPTCP_FLUSH_JOIN_LIST)) __mptcp_flush_join_list(sk, &join_list); 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); } if (__test_and_clear_bit(MPTCP_CLEAN_UNA, &msk->cb_flags)) __mptcp_clean_una_wakeup(sk); if (unlikely(msk->cb_flags)) { /* be sure to sync the msk state before taking actions * depending on sk_state (MPTCP_ERROR_REPORT) * On sk release avoid actions depending on the first subflow */ if (__test_and_clear_bit(MPTCP_SYNC_STATE, &msk->cb_flags) && msk->first) __mptcp_sync_state(sk, msk->pending_state); if (__test_and_clear_bit(MPTCP_ERROR_REPORT, &msk->cb_flags)) __mptcp_error_report(sk); if (__test_and_clear_bit(MPTCP_SYNC_SNDBUF, &msk->cb_flags)) __mptcp_sync_sndbuf(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, long status) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); struct sock *sk = subflow->conn; if (status & BIT(MPTCP_DELEGATE_SEND)) { mptcp_data_lock(sk); if (!sock_owned_by_user(sk)) __mptcp_subflow_push_pending(sk, ssk, true); else __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags); mptcp_data_unlock(sk); } if (status & BIT(MPTCP_DELEGATE_SNDBUF)) { mptcp_data_lock(sk); if (!sock_owned_by_user(sk)) __mptcp_sync_sndbuf(sk); else __set_bit(MPTCP_SYNC_SNDBUF, &mptcp_sk(sk)->cb_flags); mptcp_data_unlock(sk); } if (status & BIT(MPTCP_DELEGATE_ACK)) schedule_3rdack_retransmission(ssk); } static int mptcp_hash(struct sock *sk) { /* should never be called, * we hash the TCP subflows not the MPTCP 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); pr_debug("msk=%p, ssk=%p\n", msk, msk->first); if (WARN_ON_ONCE(!msk->first)) return -EINVAL; return inet_csk_get_port(msk->first, snum); } void mptcp_finish_connect(struct sock *ssk) { struct mptcp_subflow_context *subflow; struct mptcp_sock *msk; struct sock *sk; subflow = mptcp_subflow_ctx(ssk); sk = subflow->conn; msk = mptcp_sk(sk); pr_debug("msk=%p, token=%u\n", sk, subflow->token); subflow->map_seq = subflow->iasn; 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->local_key, subflow->local_key); mptcp_pm_new_connection(msk, ssk, 0); } 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; bool ret = true; pr_debug("msk=%p, subflow=%p\n", msk, subflow); /* mptcp socket already closing? */ if (!mptcp_is_fully_established(parent)) { subflow->reset_reason = MPTCP_RST_EMPTCP; return false; } /* active subflow, already present inside the conn_list */ if (!list_empty(&subflow->node)) { mptcp_subflow_joined(msk, ssk); mptcp_propagate_sndbuf(parent, ssk); return true; } if (!mptcp_pm_allow_new_subflow(msk)) goto err_prohibited; /* If we can't acquire msk socket lock here, let the release callback * handle it */ mptcp_data_lock(parent); if (!sock_owned_by_user(parent)) { ret = __mptcp_finish_join(msk, ssk); if (ret) { sock_hold(ssk); list_add_tail(&subflow->node, &msk->conn_list); } } else { sock_hold(ssk); list_add_tail(&subflow->node, &msk->join_list); __set_bit(MPTCP_FLUSH_JOIN_LIST, &msk->cb_flags); } mptcp_data_unlock(parent); if (!ret) { err_prohibited: subflow->reset_reason = MPTCP_RST_EPROHIBIT; return false; } return true; } static void mptcp_shutdown(struct sock *sk, int how) { pr_debug("sk=%p, how=%d\n", 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 READ_ONCE(sk->sk_forward_alloc) + READ_ONCE(mptcp_sk(sk)->rmem_fwd_alloc); } static int mptcp_ioctl_outq(const struct mptcp_sock *msk, u64 v) { const struct sock *sk = (void *)msk; u64 delta; if (sk->sk_state == TCP_LISTEN) return -EINVAL; if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) return 0; delta = msk->write_seq - v; if (__mptcp_check_fallback(msk) && msk->first) { struct tcp_sock *tp = tcp_sk(msk->first); /* the first subflow is disconnected after close - see * __mptcp_close_ssk(). tcp_disconnect() moves the write_seq * so ignore that status, too. */ if (!((1 << msk->first->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE))) delta += READ_ONCE(tp->write_seq) - tp->snd_una; } if (delta > INT_MAX) delta = INT_MAX; return (int)delta; } static int mptcp_ioctl(struct sock *sk, int cmd, int *karg) { struct mptcp_sock *msk = mptcp_sk(sk); bool slow; switch (cmd) { case SIOCINQ: if (sk->sk_state == TCP_LISTEN) return -EINVAL; lock_sock(sk); __mptcp_move_skbs(msk); *karg = mptcp_inq_hint(sk); release_sock(sk); break; case SIOCOUTQ: slow = lock_sock_fast(sk); *karg = mptcp_ioctl_outq(msk, READ_ONCE(msk->snd_una)); unlock_sock_fast(sk, slow); break; case SIOCOUTQNSD: slow = lock_sock_fast(sk); *karg = mptcp_ioctl_outq(msk, msk->snd_nxt); unlock_sock_fast(sk, slow); break; default: return -ENOIOCTLCMD; } return 0; } 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_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) { struct mptcp_subflow_context *subflow; struct mptcp_sock *msk = mptcp_sk(sk); int err = -EINVAL; struct sock *ssk; ssk = __mptcp_nmpc_sk(msk); if (IS_ERR(ssk)) return PTR_ERR(ssk); mptcp_set_state(sk, TCP_SYN_SENT); subflow = mptcp_subflow_ctx(ssk); #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(ssk)->md5sig_info)) mptcp_subflow_early_fallback(msk, subflow); #endif if (subflow->request_mptcp && mptcp_token_new_connect(ssk)) { MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_TOKENFALLBACKINIT); mptcp_subflow_early_fallback(msk, subflow); } WRITE_ONCE(msk->write_seq, subflow->idsn); WRITE_ONCE(msk->snd_nxt, subflow->idsn); WRITE_ONCE(msk->snd_una, subflow->idsn); if (likely(!__mptcp_check_fallback(msk))) MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVE); /* if reaching here via the fastopen/sendmsg path, the caller already * acquired the subflow socket lock, too. */ if (!msk->fastopening) lock_sock(ssk); /* the following mirrors closely a very small chunk of code from * __inet_stream_connect() */ if (ssk->sk_state != TCP_CLOSE) goto out; if (BPF_CGROUP_PRE_CONNECT_ENABLED(ssk)) { err = ssk->sk_prot->pre_connect(ssk, uaddr, addr_len); if (err) goto out; } err = ssk->sk_prot->connect(ssk, uaddr, addr_len); if (err < 0) goto out; inet_assign_bit(DEFER_CONNECT, sk, inet_test_bit(DEFER_CONNECT, ssk)); out: if (!msk->fastopening) release_sock(ssk); /* on successful connect, the msk state will be moved to established by * subflow_finish_connect() */ if (unlikely(err)) { /* avoid leaving a dangling token in an unconnected socket */ mptcp_token_destroy(msk); mptcp_set_state(sk, TCP_CLOSE); return err; } mptcp_copy_inaddrs(sk, ssk); return 0; } static struct proto mptcp_prot = { .name = "MPTCP", .owner = THIS_MODULE, .init = mptcp_init_sock, .connect = mptcp_connect, .disconnect = mptcp_disconnect, .close = mptcp_close, .setsockopt = mptcp_setsockopt, .getsockopt = mptcp_getsockopt, .shutdown = mptcp_shutdown, .destroy = mptcp_destroy, .sendmsg = mptcp_sendmsg, .ioctl = mptcp_ioctl, .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, .stream_memory_free = mptcp_stream_memory_free, .sockets_allocated = &mptcp_sockets_allocated, .memory_allocated = &tcp_memory_allocated, .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc, .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 sock *ssk, *sk = sock->sk; int err = -EINVAL; lock_sock(sk); ssk = __mptcp_nmpc_sk(msk); if (IS_ERR(ssk)) { err = PTR_ERR(ssk); goto unlock; } if (sk->sk_family == AF_INET) err = inet_bind_sk(ssk, uaddr, addr_len); #if IS_ENABLED(CONFIG_MPTCP_IPV6) else if (sk->sk_family == AF_INET6) err = inet6_bind_sk(ssk, uaddr, addr_len); #endif if (!err) mptcp_copy_inaddrs(sk, ssk); unlock: release_sock(sk); return err; } static int mptcp_listen(struct socket *sock, int backlog) { struct mptcp_sock *msk = mptcp_sk(sock->sk); struct sock *sk = sock->sk; struct sock *ssk; int err; pr_debug("msk=%p\n", msk); lock_sock(sk); err = -EINVAL; if (sock->state != SS_UNCONNECTED || sock->type != SOCK_STREAM) goto unlock; ssk = __mptcp_nmpc_sk(msk); if (IS_ERR(ssk)) { err = PTR_ERR(ssk); goto unlock; } mptcp_set_state(sk, TCP_LISTEN); sock_set_flag(sk, SOCK_RCU_FREE); lock_sock(ssk); err = __inet_listen_sk(ssk, backlog); release_sock(ssk); mptcp_set_state(sk, inet_sk_state_load(ssk)); if (!err) { sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); mptcp_copy_inaddrs(sk, ssk); mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CREATED); } unlock: release_sock(sk); return err; } static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, struct proto_accept_arg *arg) { struct mptcp_sock *msk = mptcp_sk(sock->sk); struct sock *ssk, *newsk; pr_debug("msk=%p\n", msk); /* Buggy applications can call accept on socket states other then LISTEN * but no need to allocate the first subflow just to error out. */ ssk = READ_ONCE(msk->first); if (!ssk) return -EINVAL; pr_debug("ssk=%p, listener=%p\n", ssk, mptcp_subflow_ctx(ssk)); newsk = inet_csk_accept(ssk, arg); if (!newsk) return arg->err; pr_debug("newsk=%p, subflow is mptcp=%d\n", newsk, 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 tcpfallback; } newsk = new_mptcp_sock; MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_MPCAPABLEPASSIVEACK); newsk->sk_kern_sock = arg->kern; lock_sock(newsk); __inet_accept(sock, newsock, newsk); set_bit(SOCK_CUSTOM_SOCKOPT, &newsock->flags); msk = mptcp_sk(newsk); msk->in_accept_queue = 0; /* set ssk->sk_socket of accept()ed flows to mptcp socket. * This is needed so NOSPACE flag can be set from tcp stack. */ mptcp_for_each_subflow(msk, subflow) { struct sock *ssk = mptcp_subflow_tcp_sock(subflow); if (!ssk->sk_socket) mptcp_sock_graft(ssk, newsock); } /* Do late cleanup for the first subflow as necessary. Also * deal with bad peers not doing a complete shutdown. */ if (unlikely(inet_sk_state_load(msk->first) == TCP_CLOSE)) { __mptcp_close_ssk(newsk, msk->first, mptcp_subflow_ctx(msk->first), 0); if (unlikely(list_is_singular(&msk->conn_list))) mptcp_set_state(newsk, TCP_CLOSE); } } else { tcpfallback: newsk->sk_kern_sock = arg->kern; lock_sock(newsk); __inet_accept(sock, newsock, newsk); /* we are being invoked after accepting 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. */ WRITE_ONCE(newsock->sk->sk_socket->ops, mptcp_fallback_tcp_ops(newsock->sk)); } release_sock(newsk); return 0; } static __poll_t mptcp_check_writeable(struct mptcp_sock *msk) { struct sock *sk = (struct sock *)msk; if (__mptcp_stream_is_writeable(sk, 1)) return EPOLLOUT | EPOLLWRNORM; set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); smp_mb__after_atomic(); /* NOSPACE is changed by mptcp_write_space() */ if (__mptcp_stream_is_writeable(sk, 1)) 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; u8 shutdown; 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\n", msk, state, msk->flags); if (state == TCP_LISTEN) { struct sock *ssk = READ_ONCE(msk->first); if (WARN_ON_ONCE(!ssk)) return 0; return inet_csk_listen_poll(ssk); } shutdown = READ_ONCE(sk->sk_shutdown); if (shutdown == SHUTDOWN_MASK || state == TCP_CLOSE) mask |= EPOLLHUP; if (shutdown & RCV_SHUTDOWN) mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP; if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) { mask |= mptcp_check_readable(sk); if (shutdown & SEND_SHUTDOWN) mask |= EPOLLOUT | EPOLLWRNORM; else mask |= mptcp_check_writeable(msk); } else if (state == TCP_SYN_SENT && inet_test_bit(DEFER_CONNECT, sk)) { /* cf tcp_poll() note about TFO */ mask |= EPOLLOUT | EPOLLWRNORM; } /* This barrier is coupled with smp_wmb() in __mptcp_error_report() */ smp_rmb(); if (READ_ONCE(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 = inet_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, .set_rcvlowat = mptcp_set_rcvlowat, }; 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_process_delegated(ssk, xchg(&subflow->delegated_status, 0)); } else { /* 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. */ smp_wmb(); clear_bit(MPTCP_DELEGATE_SCHEDULED, &subflow->delegated_status); } 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_napi_add_tx(&mptcp_napi_dev, &delegated->napi, mptcp_napi_poll); napi_enable(&delegated->napi); } mptcp_subflow_init(); mptcp_pm_init(); mptcp_sched_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 = inet_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, #ifdef CONFIG_COMPAT .compat_ioctl = inet6_compat_ioctl, #endif .set_rcvlowat = mptcp_set_rcvlowat, }; static struct proto mptcp_v6_prot; 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; strscpy(mptcp_v6_prot.name, "MPTCPv6", sizeof(mptcp_v6_prot.name)); mptcp_v6_prot.slab = NULL; mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock); mptcp_v6_prot.ipv6_pinfo_offset = offsetof(struct mptcp6_sock, np); 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
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