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-rw-r--r--net/mptcp/protocol.c25
1 files changed, 13 insertions, 12 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 939a5045181a..9936e33ac351 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -97,12 +97,7 @@ static struct socket *__mptcp_tcp_fallback(struct mptcp_sock *msk)
if (likely(!__mptcp_needs_tcp_fallback(msk)))
return NULL;
- if (msk->subflow) {
- release_sock((struct sock *)msk);
- return msk->subflow;
- }
-
- return NULL;
+ return msk->subflow;
}
static bool __mptcp_can_create_subflow(const struct mptcp_sock *msk)
@@ -734,9 +729,10 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
goto out;
}
+fallback:
ssock = __mptcp_tcp_fallback(msk);
if (unlikely(ssock)) {
-fallback:
+ release_sock(sk);
pr_debug("fallback passthrough");
ret = sock_sendmsg(ssock, msg);
return ret >= 0 ? ret + copied : (copied ? copied : ret);
@@ -769,8 +765,14 @@ fallback:
if (ret < 0)
break;
if (ret == 0 && unlikely(__mptcp_needs_tcp_fallback(msk))) {
+ /* Can happen for passive sockets:
+ * 3WHS negotiated MPTCP, but first packet after is
+ * plain TCP (e.g. due to middlebox filtering unknown
+ * options).
+ *
+ * Fall back to TCP.
+ */
release_sock(ssk);
- ssock = __mptcp_tcp_fallback(msk);
goto fallback;
}
@@ -883,6 +885,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
ssock = __mptcp_tcp_fallback(msk);
if (unlikely(ssock)) {
fallback:
+ release_sock(sk);
pr_debug("fallback-read subflow=%p",
mptcp_subflow_ctx(ssock->sk));
copied = sock_recvmsg(ssock, msg, flags);
@@ -1467,12 +1470,11 @@ static int mptcp_setsockopt(struct sock *sk, int level, int optname,
*/
lock_sock(sk);
ssock = __mptcp_tcp_fallback(msk);
+ release_sock(sk);
if (ssock)
return tcp_setsockopt(ssock->sk, level, optname, optval,
optlen);
- release_sock(sk);
-
return -EOPNOTSUPP;
}
@@ -1492,12 +1494,11 @@ static int mptcp_getsockopt(struct sock *sk, int level, int optname,
*/
lock_sock(sk);
ssock = __mptcp_tcp_fallback(msk);
+ release_sock(sk);
if (ssock)
return tcp_getsockopt(ssock->sk, level, optname, optval,
option);
- release_sock(sk);
-
return -EOPNOTSUPP;
}