net: Allow accepted sockets to be bound to l3mdev domain
Allow accepted sockets to derive their sk_bound_dev_if setting from the
l3mdev domain in which the packets originated. A sysctl setting is added
to control the behavior which is similar to sk_mark and
sysctl_tcp_fwmark_accept.
This effectively allow a process to have a "VRF-global" listen socket,
with child sockets bound to the VRF device in which the packet originated.
A similar behavior can be achieved using sk_mark, but a solution using marks
is incomplete as it does not handle duplicate addresses in different L3
domains/VRFs. Allowing sockets to inherit the sk_bound_dev_if from l3mdev
domain provides a complete solution.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 2d656ee..7b1fddc 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -6204,7 +6204,7 @@
tcp_openreq_init(req, &tmp_opt, skb, sk);
/* Note: tcp_v6_init_req() might override ir_iif for link locals */
- inet_rsk(req)->ir_iif = sk->sk_bound_dev_if;
+ inet_rsk(req)->ir_iif = inet_request_bound_dev_if(sk, skb);
af_ops->init_req(req, sk, skb);