Do not provision dns on the webapp interface, and instead return it in interface response

Author: sharmasushant

cns/NetworkContainerContract.go

@@ -133,9 +133,11 @@ type GetInterfaceForContainerRequest struct {
 
 // GetInterfaceForContainerResponse specifies the interface for a given container ID.
 type GetInterfaceForContainerResponse struct {
-	NetworkInterface NetworkInterface
-	CnetAddressSpace []IPSubnet
-	Response         Response
+	NetworkContainerVersion string
+	NetworkInterface        NetworkInterface
+	CnetAddressSpace        []IPSubnet
+	DNSServers              []string
+	Response                Response
 }
 
 // NetworkInterface specifies the information that can be used to unquely identify an interface.

cns/networkcontainers/networkcontainers_windows.go

@@ -99,16 +99,6 @@ func createOrUpdateWithOperation(createNetworkContainerRequest cns.CreateNetwork
 		return errors.New("[Azure CNS] IPAddress in IPConfiguration of createNetworkContainerRequest is nil")
 	}
 
-	var dnsServers string
-
-	for _, element := range createNetworkContainerRequest.IPConfiguration.DNSServers {
-		dnsServers += element + ","
-	}
-
-	if dnsServers != "" && dnsServers[len(dnsServers)-1] == ',' {
-		dnsServers = dnsServers[:len(dnsServers)-1]
-	}
-
 	ipv4AddrCidr := fmt.Sprintf("%v/%d", createNetworkContainerRequest.IPConfiguration.IPSubnet.IPAddress, createNetworkContainerRequest.IPConfiguration.IPSubnet.PrefixLength)
 	log.Printf("[Azure CNS] Created ipv4Cidr as %v", ipv4AddrCidr)
 	ipv4Addr, _, err := net.ParseCIDR(ipv4AddrCidr)
@@ -128,8 +118,6 @@ func createOrUpdateWithOperation(createNetworkContainerRequest cns.CreateNetwork
 		ipv4NetStr,
 		"/gateway",
 		createNetworkContainerRequest.IPConfiguration.GatewayIPAddress,
-		"/dns",
-		dnsServers,
 		"/weakhostsend",
 		"true",
 		"/weakhostreceive",

cns/restserver/restserver.go

@@ -1194,17 +1194,22 @@ func (service *httpRestService) getInterfaceForContainer(w http.ResponseWriter,
 	var interfaceName string
 	var ipaddress string
 	var cnetSpace []cns.IPSubnet
+	var dnsServers []string
+	var version string
 
 	if ok {
 		savedReq := containerDetails.CreateNetworkContainerRequest
 		interfaceName = savedReq.NetworkContainerid
 		cnetSpace = savedReq.CnetAddressSpace
 		ipaddress = savedReq.IPConfiguration.IPSubnet.IPAddress // it has to exist
+		dnsServers = savedReq.IPConfiguration.DNSServers
+		version = savedReq.Version
 	} else {
 		returnMessage = "[Azure CNS] Never received call to create this container."
 		returnCode = UnknownContainerID
 		interfaceName = ""
 		ipaddress = ""
+		version = ""
 	}
 
 	resp := cns.Response{
@@ -1213,9 +1218,11 @@ func (service *httpRestService) getInterfaceForContainer(w http.ResponseWriter,
 	}
 
 	getInterfaceForContainerResponse := cns.GetInterfaceForContainerResponse{
-		Response:         resp,
-		NetworkInterface: cns.NetworkInterface{Name: interfaceName, IPAddress: ipaddress},
-		CnetAddressSpace: cnetSpace,
+		Response:                resp,
+		NetworkInterface:        cns.NetworkInterface{Name: interfaceName, IPAddress: ipaddress},
+		CnetAddressSpace:        cnetSpace,
+		DNSServers:              dnsServers,
+		NetworkContainerVersion: version,
 	}
 
 	err = service.Listener.Encode(w, &getInterfaceForContainerResponse)