This is a note to let you know that I've just added the patch titled
mptcp: fix connect timeout handling
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mptcp-fix-connect-timeout-handling.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 786fc12457268cc9b555dde6c22ae7300d4b40e1 Mon Sep 17 00:00:00 2001
From: Paolo Abeni <pabeni@xxxxxxxxxx>
Date: Wed, 31 May 2023 12:37:03 -0700
Subject: mptcp: fix connect timeout handling
From: Paolo Abeni <pabeni@xxxxxxxxxx>
commit 786fc12457268cc9b555dde6c22ae7300d4b40e1 upstream.
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@xxxxxxxxxx>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/399
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Mat Martineau <martineau@xxxxxxxxxx>
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Mat Martineau <martineau@xxxxxxxxxx>
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/mptcp/protocol.c | 29 +++++++----------------------
net/mptcp/protocol.h | 1 -
2 files changed, 7 insertions(+), 23 deletions(-)
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1683,7 +1683,6 @@ static int mptcp_sendmsg_fastopen(struct
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;
@@ -3638,9 +3637,9 @@ static int mptcp_connect(struct sock *sk
* 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
@@ -3653,12 +3652,10 @@ static int mptcp_connect(struct sock *sk
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 = {
@@ -3717,18 +3714,6 @@ 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);
@@ -3879,7 +3864,7 @@ static const struct proto_ops mptcp_stre
.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,
@@ -3974,7 +3959,7 @@ static const struct proto_ops mptcp_v6_s
.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,
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -288,7 +288,6 @@ 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;
Patches currently in stable-queue which might be from pabeni@xxxxxxxxxx are
queue-6.1/net-dsa-mv88e6xxx-increase-wait-after-reset-deactiva.patch
queue-6.1/net-smc-don-t-use-rmbs-not-mapped-to-new-link-in-smc.patch
queue-6.1/net-smc-scan-from-current-rmb-list-when-no-position-.patch
queue-6.1/udp6-fix-race-condition-in-udp6_sendmsg-connect.patch
queue-6.1/selftests-mptcp-connect-skip-if-mptcp-is-not-supported.patch
queue-6.1/mptcp-add-annotations-around-msk-subflow-accesses.patch
queue-6.1/selftests-mptcp-sockopt-skip-if-mptcp-is-not-supported.patch
queue-6.1/mptcp-fix-data-race-around-msk-first-access.patch
queue-6.1/mptcp-avoid-unneeded-__mptcp_nmpc_socket-usage.patch
queue-6.1/selftests-mptcp-join-skip-if-mptcp-is-not-supported.patch
queue-6.1/selftests-mptcp-pm-nl-skip-if-mptcp-is-not-supported.patch
queue-6.1/tcp-deny-tcp_disconnect-when-threads-are-waiting.patch
queue-6.1/selftests-mptcp-userspace-pm-skip-if-mptcp-is-not-supported.patch
queue-6.1/net-sched-flower-fix-possible-oob-write-in-fl_set_ge.patch
queue-6.1/mptcp-consolidate-passive-msk-socket-initialization.patch
queue-6.1/mptcp-fix-active-subflow-finalization.patch
queue-6.1/mptcp-avoid-unneeded-address-copy.patch
queue-6.1/mptcp-simplify-subflow_syn_recv_sock.patch
queue-6.1/mptcp-add-annotations-around-sk-sk_shutdown-accesses.patch
queue-6.1/mptcp-fix-connect-timeout-handling.patch
queue-6.1/tcp-fix-mishandling-when-the-sack-compression-is-def.patch
