Merge pull request #6810 from phemmer/4442-hairpin-nat

Support hairpin NAT

pkg/iptables/iptables.go

@@ -73,7 +73,6 @@ func (c *Chain) Forward(action Action, ip net.IP, port int, proto, dest_addr str
 		"-p", proto,
 		"-d", daddr,
 		"--dport", strconv.Itoa(port),
-		"!", "-i", c.Bridge,
 		"-j", "DNAT",
 		"--to-destination", net.JoinHostPort(dest_addr, strconv.Itoa(dest_port))); err != nil {
 		return err
@@ -97,6 +96,17 @@ func (c *Chain) Forward(action Action, ip net.IP, port int, proto, dest_addr str
 		return fmt.Errorf("Error iptables forward: %s", output)
 	}
 
+	if output, err := Raw("-t", "nat", string(fAction), "POSTROUTING",
+		"-p", proto,
+		"-s", dest_addr,
+		"-d", dest_addr,
+		"--dport", strconv.Itoa(dest_port),
+		"-j", "MASQUERADE"); err != nil {
+		return err
+	} else if len(output) != 0 {
+		return fmt.Errorf("Error iptables forward: %s", output)
+	}
+
 	return nil
 }