mptcp: SO_KEEPALIVE: fix getsockopt support

[ Upstream commit a65198136eaa15b74ee0abf73f12ef83d469a334 ]

SO_KEEPALIVE support has to be set on each subflow: on each TCP socket,
where sk_prot->keepalive is defined. Technically, nothing has to be done
on the MPTCP socket. That's why mptcp_sol_socket_sync_intval() was
called instead of mptcp_sol_socket_intval().

Except that when nothing is done on the MPTCP socket, the
getsockopt(SO_KEEPALIVE), handled in net/core/sock.c:sk_getsockopt(),
will not know if SO_KEEPALIVE has been set on the different subflows or
not.

The fix is simple: simply call mptcp_sol_socket_intval() which will end
up calling net/core/sock.c:sk_setsockopt() where the SOCK_KEEPOPEN flag
will be set, the one used in sk_getsockopt().

So now, getsockopt(SO_KEEPALIVE) on an MPTCP socket will return the same
value as the one previously set with setsockopt(SO_KEEPALIVE).

Fixes: 1b3e7ede1365 ("mptcp: setsockopt: handle SO_KEEPALIVE and SO_PRIORITY")
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20240514011335.176158-2-martineau@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 4bb305342fcc72a3e3b0571d5a3d62acc78ae9b9..bd797d8f72ab1e8c741f762c997b9bfacbee70e3 100644 (file)
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -177,8 +177,6 @@ static int mptcp_setsockopt_sol_socket_int(struct mptcp_sock *msk, int optname,
 
        switch (optname) {
        case SO_KEEPALIVE:
-               mptcp_sol_socket_sync_intval(msk, optname, val);
-               return 0;
        case SO_DEBUG:
        case SO_MARK:
        case SO_PRIORITY: