iptables - filter packets using outgoing interface.

Enables commands with -o (--out-interface) for iptables rules.
$ iptables -A OUTPUT -o eth0 -j ACCEPT

PiperOrigin-RevId: 310642286

1 files changed, 15 insertions, 0 deletions

diff --git a/test/iptables/iptables_util.go b/test/iptables/iptables_util.go
index 2f988cd18..7146edbb9 100644
--- a/test/iptables/iptables_util.go
+++ b/test/iptables/iptables_util.go
@@ -169,3 +169,18 @@ func localAddrs() ([]string, error) {
 	}
 	return addrStrs, nil
 }
+
+// getInterfaceName returns the name of the interface other than loopback.
+func getInterfaceName() (string, bool) {
+	var ifname string
+	if interfaces, err := net.Interfaces(); err == nil {
+		for _, intf := range interfaces {
+			if intf.Name != "lo" {
+				ifname = intf.Name
+				break
+			}
+		}
+	}
+
+	return ifname, ifname != ""
+}