tcp_splice: Improve logic deciding when to splice

This makes several tweaks to improve the logic which decides whether
we're able to use the splice method for a new connection.

 * Rather than only calling tcp_splice_conn_from_sock() in pasta mode, we
   check for pasta mode within it, better localising the checks.
 * Previously if we got a connection from a non-loopback address we'd
   always fall back to the "tap" path, even if the  connection was on a
   socket in the namespace.  If we did get a non-loopback address on a
   namespace socket, something has gone wrong and the "tap" path certainly
   won't be able to handle it.  Report the error and close, rather than
   passing it along to tap.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/tcp.c b/tcp.c
index 91163b8..be62a31 100644
--- a/tcp.c
+++ b/tcp.c
@@ -2737,8 +2737,7 @@ void tcp_listen_handler(struct ctx *c, union epoll_ref ref,
 	if (s < 0)
 		goto cancel;
 
-	if (c->mode == MODE_PASTA &&
-	    tcp_splice_conn_from_sock(c, ref.tcp_listen, flow, s, &sa))
+	if (tcp_splice_conn_from_sock(c, ref.tcp_listen, flow, s, &sa))
 		return;
 
 	tcp_tap_conn_from_sock(c, ref.tcp_listen, flow, s, &sa, now);