[PATCH] fwd: Keep listening on remaining rules if one of them fails to bind

[Hayato Kiwata <dev@haytok.jp>]

fwd_listen_sync_() breaks out of the loop as soon as fwd_sync_one()
fails. So, if a single rule fails to bind(), for example because the
address isn't assigned to the host, no rule after it in the table is
even tried, and those forwards don't work.

Reproducer:

  $ pasta --ns-ifname=tap0 --mtu=65520 --config-net --address=10.0.2.100 \
    --netmask=24 --gateway=10.0.2.2 --dns-forward=10.0.2.3 --no-map-gw \
    --tcp-ns=none --udp-ns=none --ipv4-only --tcp-ports=none \
    --udp-ports=none --conf-path=/tmp/.pasta.sock \
    -- python3 -m http.server 80
  UNIX domain socket bound at /tmp/.pasta.sock
  Serving HTTP on 0.0.0.0 port 80 (http://0.0.0.0:80/) ...

  $ pesto -A --tcp-ports=192.0.2.1/8080:80 /tmp/.pasta.sock
  $ pesto -A --tcp-ports=127.0.0.1/8085:80 /tmp/.pasta.sock
  $ pesto -s /tmp/.pasta.sock
  passt/pasta configuration (/tmp/.pasta.sock)
    HOST
      TCP [192.0.2.1]:8080  =>  80
      TCP [127.0.0.1]:8085  =>  80
    SPLICE
  $ curl -sS -o /dev/null  localhost:8085
  curl: (7) Failed to connect to localhost port 8085 after 0 ms: Could not connect to server

pasta only reports the failure for port 8080, and never tries to
listen on port 8085:

  Listen failed for HOST TCP port 192.0.2.1/8080: Cannot assign requested address
  Couldn't listen on requested ports
  Error switching to new forwarding rules

Keep going through the remaining rules if fwd_sync_one() fails, and
still return -1 if any of them failed, as before.

Signed-off-by: Hayato Kiwata <dev@haytok.jp>
---
 fwd.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/fwd.c b/fwd.c
index 5679a3d..6c9df01 100644
--- a/fwd.c
+++ b/fwd.c
@@ -456,9 +456,8 @@ static int fwd_listen_sync_(void *arg)
 		ns_enter(a->c);
 
 	for (i = 0; i < a->c->fwd[a->pif]->count; i++) {
-		a->ret = fwd_sync_one(a->c, a->pif, i, a->tcpmap, a->udpmap);
-		if (a->ret < 0)
-			break;
+		if (fwd_sync_one(a->c, a->pif, i, a->tcpmap, a->udpmap) < 0)
+			a->ret = -1;
 	}
 
 	return 0;
-- 
2.50.1 (Apple Git-155)