mptcp: sockopt: add TCP_CONGESTION and TCP_INFO

TCP_CONGESTION is set for all subflows.
The mptcp socket gains icsk_ca_ops too so it can be used to keep the
authoritative state that should be set on new/future subflows.

TCP_INFO will return first subflow only.
The out-of-tree kernel has a MPTCP_INFO getsockopt, this could be added
later on.

Acked-by: Paolo Abeni <[email protected]>
Signed-off-by: Florian Westphal <[email protected]>
Signed-off-by: Mat Martineau <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

1 files changed, 5 insertions, 0 deletions

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 5cba90948a7e..073e20078ed0 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2399,6 +2399,9 @@ static int __mptcp_init_sock(struct sock *sk)
 	/* re-use the csk retrans timer for MPTCP-level retrans */
 	timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0);
 	timer_setup(&sk->sk_timer, mptcp_timeout_timer, 0);
+
+	tcp_assign_congestion_control(sk);
+
 	return 0;
 }
 
@@ -2592,6 +2595,8 @@ static void __mptcp_destroy_sock(struct sock *sk)
 	WARN_ON_ONCE(msk->rmem_released);
 	sk_stream_kill_queues(sk);
 	xfrm_sk_free_policy(sk);
+
+	tcp_cleanup_congestion_control(sk);
 	sk_refcnt_debug_release(sk);
 	mptcp_dispose_initial_subflow(msk);
 	sock_put(sk);