From b51f9b80c032e1af1e3e7e8dc733d2d49831e982 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Fri, 27 Mar 2020 14:48:44 -0700 Subject: [PATCH] mptcp: introduce MPTCP retransmission timer The timer will be used to schedule retransmission. It's frequency is based on the current subflow RTO estimation and is reset on every una_seq update The timer is clearer for good by __mptcp_clear_xmit() Also clean MPTCP rtx queue before each transmission. Signed-off-by: Paolo Abeni Signed-off-by: Mat Martineau Signed-off-by: David S. Miller --- net/mptcp/options.c | 4 ++- net/mptcp/protocol.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++- net/mptcp/protocol.h | 2 ++ 3 files changed, 93 insertions(+), 2 deletions(-) diff --git a/net/mptcp/options.c b/net/mptcp/options.c index b0ff8ad..bd220ee 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -779,8 +779,10 @@ static void update_una(struct mptcp_sock *msk, snd_una = old_snd_una; old_snd_una = atomic64_cmpxchg(&msk->snd_una, snd_una, new_snd_una); - if (old_snd_una == snd_una) + if (old_snd_una == snd_una) { + mptcp_data_acked((struct sock *)msk); break; + } } } diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 812a646..002c631 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -251,6 +251,46 @@ static void __mptcp_flush_join_list(struct mptcp_sock *msk) spin_unlock_bh(&msk->join_list_lock); } +static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk) +{ + long tout = ssk && inet_csk(ssk)->icsk_pending ? + inet_csk(ssk)->icsk_timeout - jiffies : 0; + + if (tout <= 0) + tout = mptcp_sk(sk)->timer_ival; + mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN; +} + +static bool mptcp_timer_pending(struct sock *sk) +{ + return timer_pending(&inet_csk(sk)->icsk_retransmit_timer); +} + +static void mptcp_reset_timer(struct sock *sk) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + unsigned long tout; + + /* should never be called with mptcp level timer cleared */ + tout = READ_ONCE(mptcp_sk(sk)->timer_ival); + if (WARN_ON_ONCE(!tout)) + tout = TCP_RTO_MIN; + sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout); +} + +void mptcp_data_acked(struct sock *sk) +{ + mptcp_reset_timer(sk); +} + +static void mptcp_stop_timer(struct sock *sk) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + + sk_stop_timer(sk, &icsk->icsk_retransmit_timer); + mptcp_sk(sk)->timer_ival = 0; +} + static bool mptcp_ext_cache_refill(struct mptcp_sock *msk) { if (!msk->cached_ext) @@ -596,10 +636,15 @@ fallback: copied += ret; } + mptcp_set_timeout(sk, ssk); if (copied) { ret = copied; tcp_push(ssk, msg->msg_flags, mss_now, tcp_sk(ssk)->nonagle, size_goal); + + /* start the timer, if it's not pending */ + if (!mptcp_timer_pending(sk)) + mptcp_reset_timer(sk); } ssk_check_wmem(msk, ssk); @@ -787,6 +832,35 @@ out_err: return copied; } +static void mptcp_retransmit_handler(struct sock *sk) +{ + struct mptcp_sock *msk = mptcp_sk(sk); + + if (atomic64_read(&msk->snd_una) == msk->write_seq) + mptcp_stop_timer(sk); + else + mptcp_reset_timer(sk); +} + +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; + + bh_lock_sock(sk); + if (!sock_owned_by_user(sk)) { + mptcp_retransmit_handler(sk); + } else { + /* delegate our work to tcp_release_cb() */ + if (!test_and_set_bit(TCP_WRITE_TIMER_DEFERRED, + &sk->sk_tsq_flags)) + sock_hold(sk); + } + bh_unlock_sock(sk); + sock_put(sk); +} + /* subflow sockets can be either outgoing (connect) or incoming * (accept). * @@ -846,6 +920,9 @@ static int __mptcp_init_sock(struct sock *sk) 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); + return 0; } @@ -867,6 +944,8 @@ static void __mptcp_clear_xmit(struct sock *sk) struct mptcp_sock *msk = mptcp_sk(sk); struct mptcp_data_frag *dtmp, *dfrag; + sk_stop_timer(sk, &msk->sk.icsk_retransmit_timer); + list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) dfrag_clear(dfrag); } @@ -1155,7 +1234,8 @@ static int mptcp_getsockopt(struct sock *sk, int level, int optname, return -EOPNOTSUPP; } -#define MPTCP_DEFERRED_ALL TCPF_DELACK_TIMER_DEFERRED +#define MPTCP_DEFERRED_ALL (TCPF_DELACK_TIMER_DEFERRED | \ + TCPF_WRITE_TIMER_DEFERRED) /* this is very alike tcp_release_cb() but we must handle differently a * different set of events @@ -1171,6 +1251,8 @@ static void mptcp_release_cb(struct sock *sk) nflags = flags & ~MPTCP_DEFERRED_ALL; } while (cmpxchg(&sk->sk_tsq_flags, flags, nflags) != flags); + sock_release_ownership(sk); + if (flags & TCPF_DELACK_TIMER_DEFERRED) { struct mptcp_sock *msk = mptcp_sk(sk); struct sock *ssk; @@ -1179,6 +1261,11 @@ static void mptcp_release_cb(struct sock *sk) if (!ssk || !schedule_work(&msk->work)) __sock_put(sk); } + + if (flags & TCPF_WRITE_TIMER_DEFERRED) { + mptcp_retransmit_handler(sk); + __sock_put(sk); + } } static int mptcp_get_port(struct sock *sk, unsigned short snum) diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index a1fdb879..d222eea 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -157,6 +157,7 @@ struct mptcp_sock { u64 write_seq; u64 ack_seq; atomic64_t snd_una; + unsigned long timer_ival; u32 token; unsigned long flags; bool can_ack; @@ -326,6 +327,7 @@ void mptcp_get_options(const struct sk_buff *skb, void mptcp_finish_connect(struct sock *sk); void mptcp_data_ready(struct sock *sk, struct sock *ssk); bool mptcp_finish_join(struct sock *sk); +void mptcp_data_acked(struct sock *sk); int mptcp_token_new_request(struct request_sock *req); void mptcp_token_destroy_request(u32 token); -- 2.7.4