fix: Pass host gateway to CNI in swift mode

cni/network/invoker_cns.go

@@ -27,12 +27,13 @@ type CNSIPAMInvoker struct {
 }
 
 type IPv4ResultInfo struct {
-	podIPAddress   string
-	ncSubnetPrefix uint8
-	ncPrimaryIP    string
-	gwIPAddress    string
-	hostSubnet     string
-	hostPrimaryIP  string
+	podIPAddress       string
+	ncSubnetPrefix     uint8
+	ncPrimaryIP        string
+	ncGatewayIPAddress string
+	hostSubnet         string
+	hostPrimaryIP      string
+	hostGateway        string
 }
 
 func NewCNSInvoker(podName, namespace string) (*CNSIPAMInvoker, error) {
@@ -61,17 +62,26 @@ func (invoker *CNSIPAMInvoker) Add(nwCfg *cni.NetworkConfig, subnetPrefix *net.I
 	}
 
 	resultIPv4 := IPv4ResultInfo{
-		podIPAddress:   response.PodIpInfo.PodIPConfig.IPAddress,
-		ncSubnetPrefix: response.PodIpInfo.NetworkContainerPrimaryIPConfig.IPSubnet.PrefixLength,
-		ncPrimaryIP:    response.PodIpInfo.NetworkContainerPrimaryIPConfig.IPSubnet.IPAddress,
-		gwIPAddress:    response.PodIpInfo.NetworkContainerPrimaryIPConfig.GatewayIPAddress,
-		hostSubnet:     response.PodIpInfo.HostPrimaryIPInfo.Subnet,
-		hostPrimaryIP:  response.PodIpInfo.HostPrimaryIPInfo.PrimaryIP,
+		podIPAddress:       response.PodIpInfo.PodIPConfig.IPAddress,
+		ncSubnetPrefix:     response.PodIpInfo.NetworkContainerPrimaryIPConfig.IPSubnet.PrefixLength,
+		ncPrimaryIP:        response.PodIpInfo.NetworkContainerPrimaryIPConfig.IPSubnet.IPAddress,
+		ncGatewayIPAddress: response.PodIpInfo.NetworkContainerPrimaryIPConfig.GatewayIPAddress,
+		hostSubnet:         response.PodIpInfo.HostPrimaryIPInfo.Subnet,
+		hostPrimaryIP:      response.PodIpInfo.HostPrimaryIPInfo.PrimaryIP,
+		hostGateway:        response.PodIpInfo.HostPrimaryIPInfo.Gateway,
+	}
+
+	ncgw := net.ParseIP(resultIPv4.ncGatewayIPAddress)
+	if ncgw == nil {
+		return nil, nil, fmt.Errorf("Gateway address %v from response is invalid", resultIPv4.ncGatewayIPAddress)
 	}
 
 	// set the NC Primary IP in options
 	options[network.SNATIPKey] = resultIPv4.ncPrimaryIP
 
+	// set host gateway in options
+	options[network.HostGWKey] = resultIPv4.hostGateway
+
 	log.Printf("Received result %+v for pod %v", resultIPv4, podInfo)
 
 	result, err := getCNIIPv4Result(resultIPv4, subnetPrefix)
@@ -85,7 +95,7 @@ func (invoker *CNSIPAMInvoker) Add(nwCfg *cni.NetworkConfig, subnetPrefix *net.I
 
 func getCNIIPv4Result(info IPv4ResultInfo, subnetPrefix *net.IPNet) (*cniTypesCurr.Result, error) {
 
-	gw := net.ParseIP(info.gwIPAddress)
+	gw := net.ParseIP(info.ncGatewayIPAddress)
 	if gw == nil {
 		return nil, fmt.Errorf("Gateway address %v from response is invalid", gw)
 	}

cns/NetworkContainerContract.go

@@ -215,6 +215,7 @@ type PodIpInfo struct {
 
 // DeleteNetworkContainerRequest specifies the details about the request to delete a specifc network container.
 type HostIPInfo struct {
+	Gateway   string
 	PrimaryIP string
 	Subnet    string
 }

cns/restserver/util.go

@@ -668,6 +668,7 @@ func (service *HTTPRestService) populateIpConfigInfoUntransacted(ipConfigStatus
 
 	podIpInfo.HostPrimaryIPInfo.PrimaryIP = hostInterfaceInfo.PrimaryIP
 	podIpInfo.HostPrimaryIPInfo.Subnet = hostInterfaceInfo.Subnet
+	podIpInfo.HostPrimaryIPInfo.Gateway = hostInterfaceInfo.Gateway
 
 	return nil
 }

network/bridge_networkclient_linux.go

@@ -50,18 +50,32 @@ func (client *LinuxBridgeClient) CreateBridge() error {
 
 func (client *LinuxBridgeClient) AddRoutes(nwInfo *NetworkInfo, interfaceName string) error {
 	if client.nwInfo.IPAMType == AzureCNS {
-		// add pod subnet to host
+
+		// fetch the host gateway IP from options
+		gwIP := client.nwInfo.Options[HostGWKey]
+		if gwIP == nil {
+			return fmt.Errorf("Host gateway IP in Options not set")
+		}
+
+		gatewayIP := net.ParseIP(gwIP.(string))
+		if gatewayIP == nil {
+			return fmt.Errorf("Invalid host gateway IP: %+v", gwIP)
+		}
+
+		// add host gateway as the default gateway for pod IP's
 		devIf, _ := net.InterfaceByName(interfaceName)
 		ifIndex := devIf.Index
-		family := netlink.GetIpAddressFamily(Ipv4DefaultRouteDstPrefix.IP)
+		family := netlink.GetIpAddressFamily(gatewayIP)
 
 		nlRoute := &netlink.Route{
 			Family:    family,
 			Dst:       &client.nwInfo.PodSubnet.Prefix,
-			Gw:        Ipv4DefaultRouteDstPrefix.IP,
+			Gw:        gatewayIP,
 			LinkIndex: ifIndex,
 		}
 
+		log.Printf("Adding Swift route %+v", nlRoute)
+
 		if err := netlink.AddIpRoute(nlRoute); err != nil {
 			if !strings.Contains(strings.ToLower(err.Error()), "file exists") {
 				return fmt.Errorf("Failed to add route to host interface with error: %v", err)

network/manager.go

@@ -21,6 +21,7 @@ const (
 	VlanIDKey   = "VlanID"
 	AzureCNS    = "azure-cns"
 	SNATIPKey   = "NCPrimaryIPKey"
+	HostGWKey   = "HostGatewayIP"
 	genericData = "com.docker.network.generic"
 )