From: Florian Westphal Date: Mon, 16 Nov 2020 09:48:13 +0000 (+0100) Subject: mptcp: keep track of advertised windows right edge X-Git-Tag: accepted/tizen/unified/20230118.172025~8321^2~246^2~1 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=6f8a612a33e426d473f7161d1950dc00a613494b;p=platform%2Fkernel%2Flinux-rpi.git mptcp: keep track of advertised windows right edge Before sending 'x' new bytes also check that the new snd_una would be within the permitted receive window. For every ACK that also contains a DSS ack, check whether its tcp-level receive window would advance the current mptcp window right edge and update it if so. Signed-off-by: Florian Westphal Co-developed-by: Paolo Abeni Signed-off-by: Paolo Abeni Signed-off-by: Jakub Kicinski --- diff --git a/net/mptcp/options.c b/net/mptcp/options.c index 1be272d..f2d1e27 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -809,11 +809,14 @@ static u64 expand_ack(u64 old_ack, u64 cur_ack, bool use_64bit) return cur_ack; } -static void update_una(struct mptcp_sock *msk, - struct mptcp_options_received *mp_opt) +static void ack_update_msk(struct mptcp_sock *msk, + const struct sock *ssk, + struct mptcp_options_received *mp_opt) { u64 new_snd_una, snd_una, old_snd_una = atomic64_read(&msk->snd_una); + u64 new_wnd_end, wnd_end, old_wnd_end = atomic64_read(&msk->wnd_end); u64 snd_nxt = READ_ONCE(msk->snd_nxt); + struct sock *sk = (struct sock *)msk; /* avoid ack expansion on update conflict, to reduce the risk of * wrongly expanding to a future ack sequence number, which is way @@ -825,12 +828,25 @@ static void update_una(struct mptcp_sock *msk, if (after64(new_snd_una, snd_nxt)) new_snd_una = old_snd_una; + new_wnd_end = new_snd_una + tcp_sk(ssk)->snd_wnd; + + while (after64(new_wnd_end, old_wnd_end)) { + wnd_end = old_wnd_end; + old_wnd_end = atomic64_cmpxchg(&msk->wnd_end, wnd_end, + new_wnd_end); + if (old_wnd_end == wnd_end) { + if (mptcp_send_head(sk)) + mptcp_schedule_work(sk); + break; + } + } + while (after64(new_snd_una, old_snd_una)) { snd_una = old_snd_una; old_snd_una = atomic64_cmpxchg(&msk->snd_una, snd_una, new_snd_una); if (old_snd_una == snd_una) { - mptcp_data_acked((struct sock *)msk); + mptcp_data_acked(sk); break; } } @@ -930,7 +946,7 @@ void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb) * monodirectional flows will stuck */ if (mp_opt.use_ack) - update_una(msk, &mp_opt); + ack_update_msk(msk, sk, &mp_opt); /* Zero-data-length packets are dropped by the caller and not * propagated to the MPTCP layer, so the skb extension does not diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 7fcd260..5a92b92 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -57,6 +57,12 @@ static struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk) return msk->subflow; } +/* Returns end sequence number of the receiver's advertised window */ +static u64 mptcp_wnd_end(const struct mptcp_sock *msk) +{ + return atomic64_read(&msk->wnd_end); +} + static bool mptcp_is_tcpsk(struct sock *sk) { struct socket *sock = sk->sk_socket; @@ -174,6 +180,7 @@ static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb) if (after64(seq, max_seq)) { /* out of window */ mptcp_drop(sk, skb); + pr_debug("oow by %ld", (unsigned long)seq - (unsigned long)max_seq); MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW); return; } @@ -847,6 +854,7 @@ static void mptcp_clean_una(struct sock *sk) */ if (__mptcp_check_fallback(msk)) atomic64_set(&msk->snd_una, msk->snd_nxt); + snd_una = atomic64_read(&msk->snd_una); list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) { @@ -944,12 +952,30 @@ struct mptcp_sendmsg_info { unsigned int flags; }; +static int mptcp_check_allowed_size(struct mptcp_sock *msk, u64 data_seq, + int avail_size) +{ + u64 window_end = mptcp_wnd_end(msk); + + if (__mptcp_check_fallback(msk)) + return avail_size; + + if (!before64(data_seq + avail_size, window_end)) { + u64 allowed_size = window_end - data_seq; + + return min_t(unsigned int, allowed_size, avail_size); + } + + return avail_size; +} + static 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; struct mptcp_sock *msk = mptcp_sk(sk); + bool zero_window_probe = false; struct mptcp_ext *mpext = NULL; struct sk_buff *skb, *tail; bool can_collapse = false; @@ -979,6 +1005,16 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, avail_size = info->size_goal - skb->len; } + /* Zero window and all data acked? Probe. */ + avail_size = mptcp_check_allowed_size(msk, data_seq, avail_size); + if (avail_size == 0) { + if (skb || atomic64_read(&msk->snd_una) != msk->snd_nxt) + return 0; + zero_window_probe = true; + data_seq = atomic64_read(&msk->snd_una) - 1; + avail_size = 1; + } + if (WARN_ON_ONCE(info->sent > info->limit || info->limit > dfrag->data_len)) return 0; @@ -996,6 +1032,7 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, if (skb == tail) { WARN_ON_ONCE(!can_collapse); mpext->data_len += ret; + WARN_ON_ONCE(zero_window_probe); goto out; } @@ -1013,6 +1050,12 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, mpext->data_seq, mpext->subflow_seq, mpext->data_len, mpext->dsn64); + if (zero_window_probe) { + mptcp_subflow_ctx(ssk)->rel_write_seq += ret; + mpext->frozen = 1; + ret = 0; + tcp_push_pending_frames(ssk); + } out: mptcp_subflow_ctx(ssk)->rel_write_seq += ret; return ret; @@ -1866,7 +1909,7 @@ static void mptcp_worker(struct work_struct *work) info.limit = dfrag->already_sent; while (info.sent < dfrag->already_sent) { ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); - if (ret < 0) + if (ret <= 0) break; MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS); @@ -2226,6 +2269,8 @@ struct sock *mptcp_sk_clone(const struct sock *sk, msk->write_seq = subflow_req->idsn + 1; msk->snd_nxt = msk->write_seq; atomic64_set(&msk->snd_una, msk->write_seq); + atomic64_set(&msk->wnd_end, msk->snd_nxt + req->rsk_rcv_wnd); + if (mp_opt->mp_capable) { msk->can_ack = true; msk->remote_key = mp_opt->sndr_key; @@ -2258,6 +2303,8 @@ void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk) TCP_INIT_CWND * tp->advmss); if (msk->rcvq_space.space == 0) msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT; + + atomic64_set(&msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd); } static struct sock *mptcp_accept(struct sock *sk, int flags, int *err, diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 8345011..b4c8dbe 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -215,6 +215,7 @@ struct mptcp_sock { struct sock *last_snd; int snd_burst; atomic64_t snd_una; + atomic64_t wnd_end; unsigned long timer_ival; u32 token; unsigned long flags;