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authorPaolo Abeni <pabeni@redhat.com>2023-05-31 22:37:03 +0300
committerJakub Kicinski <kuba@kernel.org>2023-06-01 20:04:04 +0300
commit786fc12457268cc9b555dde6c22ae7300d4b40e1 (patch)
tree00569cbd4f715ea9da2c483a60354e3c0e9bd1f8 /net/mptcp
parent3021dbfe3ef0aae502347f62824b292697f55f88 (diff)
downloadlinux-786fc12457268cc9b555dde6c22ae7300d4b40e1.tar.xz
mptcp: fix connect timeout handling
Ondrej reported a functional issue WRT timeout handling on connect with a nice reproducer. The problem is that the current mptcp connect waits for both the MPTCP socket level timeout, and the first subflow socket timeout. The latter is not influenced/touched by the exposed setsockopt(). Overall the above makes the SO_SNDTIMEO a no-op on connect. Since mptcp_connect is invoked via inet_stream_connect and the latter properly handle the MPTCP level timeout, we can address the issue making the nested subflow level connect always unblocking. This also allow simplifying a bit the code, dropping an ugly hack to handle the fastopen and custom proto_ops connect. The issues predates the blamed commit below, but the current resolution requires the infrastructure introduced there. Fixes: 54f1944ed6d2 ("mptcp: factor out mptcp_connect()") Reported-by: Ondrej Mosnacek <omosnace@redhat.com> Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/399 Cc: stable@vger.kernel.org Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/mptcp')
-rw-r--r--net/mptcp/protocol.c29
-rw-r--r--net/mptcp/protocol.h1
2 files changed, 7 insertions, 23 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 08dc53f56bc2..9cafd3b89908 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1702,7 +1702,6 @@ static int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
lock_sock(ssk);
msg->msg_flags |= MSG_DONTWAIT;
- msk->connect_flags = O_NONBLOCK;
msk->fastopening = 1;
ret = tcp_sendmsg_fastopen(ssk, msg, copied_syn, len, NULL);
msk->fastopening = 0;
@@ -3617,9 +3616,9 @@ static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
* acquired the subflow socket lock, too.
*/
if (msk->fastopening)
- err = __inet_stream_connect(ssock, uaddr, addr_len, msk->connect_flags, 1);
+ err = __inet_stream_connect(ssock, uaddr, addr_len, O_NONBLOCK, 1);
else
- err = inet_stream_connect(ssock, uaddr, addr_len, msk->connect_flags);
+ err = inet_stream_connect(ssock, uaddr, addr_len, O_NONBLOCK);
inet_sk(sk)->defer_connect = inet_sk(ssock->sk)->defer_connect;
/* on successful connect, the msk state will be moved to established by
@@ -3632,12 +3631,10 @@ static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
mptcp_copy_inaddrs(sk, ssock->sk);
- /* unblocking connect, mptcp-level inet_stream_connect will error out
- * without changing the socket state, update it here.
+ /* silence EINPROGRESS and let the caller inet_stream_connect
+ * handle the connection in progress
*/
- if (err == -EINPROGRESS)
- sk->sk_socket->state = ssock->state;
- return err;
+ return 0;
}
static struct proto mptcp_prot = {
@@ -3696,18 +3693,6 @@ unlock:
return err;
}
-static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
- int addr_len, int flags)
-{
- int ret;
-
- lock_sock(sock->sk);
- mptcp_sk(sock->sk)->connect_flags = flags;
- ret = __inet_stream_connect(sock, uaddr, addr_len, flags, 0);
- release_sock(sock->sk);
- return ret;
-}
-
static int mptcp_listen(struct socket *sock, int backlog)
{
struct mptcp_sock *msk = mptcp_sk(sock->sk);
@@ -3859,7 +3844,7 @@ static const struct proto_ops mptcp_stream_ops = {
.owner = THIS_MODULE,
.release = inet_release,
.bind = mptcp_bind,
- .connect = mptcp_stream_connect,
+ .connect = inet_stream_connect,
.socketpair = sock_no_socketpair,
.accept = mptcp_stream_accept,
.getname = inet_getname,
@@ -3954,7 +3939,7 @@ static const struct proto_ops mptcp_v6_stream_ops = {
.owner = THIS_MODULE,
.release = inet6_release,
.bind = mptcp_bind,
- .connect = mptcp_stream_connect,
+ .connect = inet_stream_connect,
.socketpair = sock_no_socketpair,
.accept = mptcp_stream_accept,
.getname = inet6_getname,
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 2d7b2c80a164..de4667dafe59 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -297,7 +297,6 @@ struct mptcp_sock {
nodelay:1,
fastopening:1,
in_accept_queue:1;
- int connect_flags;
struct work_struct work;
struct sk_buff *ooo_last_skb;
struct rb_root out_of_order_queue;