From 0530020a7c8f2204e784f0dbdc882bbd961fdbde Mon Sep 17 00:00:00 2001 From: Geliang Tang Date: Fri, 22 Apr 2022 14:55:38 -0700 Subject: [PATCH] mptcp: track and update contiguous data status This patch adds a new member allow_infinite_fallback in mptcp_sock, which is initialized to 'true' when the connection begins and is set to 'false' on any retransmit or successful MP_JOIN. Only do infinite mapping fallback if there is a single subflow AND there have been no retransmissions AND there have never been any MP_JOINs. Suggested-by: Paolo Abeni Signed-off-by: Geliang Tang Signed-off-by: Mat Martineau Signed-off-by: David S. Miller --- net/mptcp/protocol.c | 3 +++ net/mptcp/protocol.h | 1 + net/mptcp/subflow.c | 4 +++- 3 files changed, 7 insertions(+), 1 deletion(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 0492aa9308c7..6d653914e9fe 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2465,6 +2465,7 @@ static void __mptcp_retrans(struct sock *sk) dfrag->already_sent = max(dfrag->already_sent, info.sent); tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, info.size_goal); + WRITE_ONCE(msk->allow_infinite_fallback, false); } release_sock(ssk); @@ -2539,6 +2540,7 @@ static int __mptcp_init_sock(struct sock *sk) 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; mptcp_pm_data_init(msk); @@ -3275,6 +3277,7 @@ err_prohibited: } subflow->map_seq = READ_ONCE(msk->ack_seq); + WRITE_ONCE(msk->allow_infinite_fallback, false); out: mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC); diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index aca1fb56523f..88d292374599 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -263,6 +263,7 @@ struct mptcp_sock { bool rcv_fastclose; bool use_64bit_ack; /* Set when we received a 64-bit DSN */ bool csum_enabled; + bool allow_infinite_fallback; u8 recvmsg_inq:1, cork:1, nodelay:1; diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 7f26a5b04ad3..31dcb550316f 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1206,7 +1206,8 @@ fallback: if (!__mptcp_check_fallback(msk)) { /* RFC 8684 section 3.7. */ if (subflow->send_mp_fail) { - if (mptcp_has_another_subflow(ssk)) { + if (mptcp_has_another_subflow(ssk) || + !READ_ONCE(msk->allow_infinite_fallback)) { ssk->sk_err = EBADMSG; tcp_set_state(ssk, TCP_CLOSE); subflow->reset_transient = 0; @@ -1486,6 +1487,7 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc, /* discard the subflow socket */ mptcp_sock_graft(ssk, sk->sk_socket); iput(SOCK_INODE(sf)); + WRITE_ONCE(msk->allow_infinite_fallback, false); return err; failed_unlink: