net: mptcp: don't hang in mptcp_sendmsg() after TCP fallback

it's still possible for packetdrill to hang in mptcp_sendmsg(), when the
MPTCP socket falls back to regular TCP (e.g. after receiving unsupported
flags/version during the three-way handshake). Adjust MPTCP socket state
earlier, to ensure correct functionality of mptcp_sendmsg() even in case
of TCP fallback.

Fixes: 767d3ded5fb8 ("net: mptcp: don't hang before sending 'MP capable with data'")
Fixes: 1954b86016cf ("mptcp: Check connection state before attempting send")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index e959104..92d5382 100644 (file)
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1055,10 +1055,6 @@ void mptcp_finish_connect(struct sock *ssk)
        WRITE_ONCE(msk->write_seq, subflow->idsn + 1);
        WRITE_ONCE(msk->ack_seq, ack_seq);
        WRITE_ONCE(msk->can_ack, 1);
-       if (inet_sk_state_load(sk) != TCP_ESTABLISHED) {
-               inet_sk_state_store(sk, TCP_ESTABLISHED);
-               sk->sk_state_change(sk);
-       }
 }
 
 static void mptcp_sock_graft(struct sock *sk, struct socket *parent)

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index e1faa88..5bae12d 100644 (file)
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -109,9 +109,15 @@ static void subflow_v6_init_req(struct request_sock *req,
 static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
 {
        struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+       struct sock *parent = subflow->conn;
 
        subflow->icsk_af_ops->sk_rx_dst_set(sk, skb);
 
+       if (inet_sk_state_load(parent) != TCP_ESTABLISHED) {
+               inet_sk_state_store(parent, TCP_ESTABLISHED);
+               parent->sk_state_change(parent);
+       }
+
        if (!subflow->conn_finished) {
                pr_debug("subflow=%p, remote_key=%llu", mptcp_subflow_ctx(sk),
                         subflow->remote_key);