force resolve host to use piv4 (#259)

src/packetgen/utils.go

@@ -90,15 +90,16 @@ func LocalIP() string {
 
 // ResolveHost function gets a string and returns the ip address
 func ResolveHost(host string) (string, error) {
-	addrs, err := net.LookupHost(host)
+	addrs, err := net.LookupIP(host)
 	if err != nil {
 		return "", err
 	}
 
-	// I assume net.LookupHost already handles that but just to be sure
-	if len(addrs) == 0 {
-		return "", fmt.Errorf("no addrs found for host %v", host)
+	for _, addr := range addrs {
+		if addr.To4() != nil {
+			return addr.String(), nil
+		}
 	}
 
-	return addrs[0], nil
+	return "", fmt.Errorf("no addrs found for host %v", host)
 }

testconfig.json

@@ -60,7 +60,7 @@
     {
       "type": "packetgen",
       "args": {
-        "host": "{{ resolve_host \"google.com\" }}",
+        "host": "{{ resolve_host \"localhost\" }}",
         "port": "{{ random_port }}",
         "packet": {
           "payload": "test:blah",
@@ -70,7 +70,7 @@
           },
           "ip": {
             "src_ip": "{{ local_ip }}",
-            "dst_ip": "{{ resolve_host \"google.com\" }}"
+            "dst_ip": "{{ resolve_host \"localhost\" }}"
           },
           "tcp": {
             "src_port": "{{ random_port }}",