udp: Better handling of failure to forward from reply socket

In udp_reply_sock_handler() if we're unable to forward the datagrams we
just print an error.  Generally this means we have an unsupported pair of
pifs in the flow table, though, and that hasn't change.  So, next time we
get a matching packet we'll just get the same failure.  In vhost-user mode
we don't even dequeue the incoming packets which triggered this so we're
likely to get the same failure immediately.

Instead, close the flow, in the same we we do for an unrecoverable error.

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

1 files changed, 8 insertions, 7 deletions

diff --git a/udp.c b/udp.c
index f417cea..96e48dd 100644
--- a/udp.c
+++ b/udp.c
@@ -812,9 +812,7 @@ void udp_reply_sock_handler(const struct ctx *c, union epoll_ref ref,
 	if (events & EPOLLERR) {
 		if (udp_sock_errs(c, ref) < 0) {
 			flow_err(uflow, "Unrecoverable error on reply socket");
-			flow_err_details(uflow);
-			udp_flow_close(c, uflow);
-			return;
+			goto fail;
 		}
 	}
 
@@ -829,12 +827,15 @@ void udp_reply_sock_handler(const struct ctx *c, union epoll_ref ref,
 			ret = udp_buf_reply_sock_data(c, s, tosidx, now);
 
 		if (!ret) {
-			flow_err(uflow,
-				 "No support for forwarding UDP from %s to %s",
-				 pif_name(pif_at_sidx(ref.flowside)),
-				 pif_name(pif_at_sidx(tosidx)));
+			flow_err(uflow, "Unable to forward UDP");
+			goto fail;
 		}
 	}
+	return;
+
+fail:
+	flow_err_details(uflow);
+	udp_flow_close(c, uflow);
 }
 
 /**