Add an enforce network validation flag for docker to not break previous functionality

main.go

@@ -341,20 +341,22 @@ func resolveDomain(domain string) (string, error) {
 }
 
 var (
-	endpoint                      string
-	id                            string
-	secret                        string
-	mtu                           string
-	mtuInt                        int
-	dns                           string
-	privateKey                    wgtypes.Key
-	err                           error
-	logLevel                      string
-	updownScript                  string
-	tlsPrivateKey                 string
-	dockerSocket                  string
-	dockerContainerAsHostname     string
-	dockerContainerAsHostnameBool bool
+	endpoint                           string
+	id                                 string
+	secret                             string
+	mtu                                string
+	mtuInt                             int
+	dns                                string
+	privateKey                         wgtypes.Key
+	err                                error
+	logLevel                           string
+	updownScript                       string
+	tlsPrivateKey                      string
+	dockerSocket                       string
+	dockerContainerAsHostname          string
+	dockerContainerAsHostnameBool      bool
+	dockerEnforceNetworkValidation     string
+	dockerEnforceNetworkValidationBool bool
 )
 
 func main() {
@@ -369,6 +371,7 @@ func main() {
 	tlsPrivateKey = os.Getenv("TLS_CLIENT_CERT")
 	dockerSocket = os.Getenv("DOCKER_SOCKET")
 	dockerContainerAsHostname = os.Getenv("DOCKER_CONTAINER_NAME_AS_HOSTNAME")
+	dockerEnforceNetworkValidation = os.Getenv("DOCKER_ENFORCE_NETWORK_VALIDATION")
 
 	if endpoint == "" {
 		flag.StringVar(&endpoint, "endpoint", "", "Endpoint of your pangolin server")
@@ -400,6 +403,9 @@ func main() {
 	if dockerContainerAsHostname == "" {
 		flag.StringVar(&dockerContainerAsHostname, "docker-container-name-as-hostname", "false", "Use container name when hostname for networking (true or false)")
 	}
+	if dockerEnforceNetworkValidation == "" {
+		flag.StringVar(&dockerEnforceNetworkValidation, "docker-enforce-network-validation", "false", "Enforce validation of container on newt network (true or false)")
+	}
 
 	// do a --version check
 	version := flag.Bool("version", false, "Print the version")
@@ -431,6 +437,13 @@ func main() {
 		dockerContainerAsHostnameBool = false
 	}
 
+	// parse if we want to enforce container network validation
+	dockerEnforceNetworkValidationBool, err = strconv.ParseBool(dockerEnforceNetworkValidation)
+	if err != nil {
+		logger.Info("Docker enforce network validation cannot be parsed. Defaulting to 'false'")
+		dockerEnforceNetworkValidationBool = false
+	}
+
 	privateKey, err = wgtypes.GeneratePrivateKey()
 	if err != nil {
 		logger.Fatal("Failed to generate private key: %v", err)
@@ -450,6 +463,25 @@ func main() {
 		logger.Fatal("Failed to create client: %v", err)
 	}
 
+	// output env var values if set
+	logger.Debug("Endpoint: %v", endpoint)
+	logger.Debug("Log Level: %v", logLevel)
+	logger.Debug("Docker Container Name as Hostname: %v", dockerContainerAsHostnameBool)
+	logger.Debug("Docker Network Validation Enabled: %v", dockerEnforceNetworkValidationBool)
+	logger.Debug("TLS Private Key Set: %v", tlsPrivateKey != "")
+	if dns != "" {
+		logger.Debug("Dns: %v", dns)
+	}
+	if dockerSocket != "" {
+		logger.Debug("Docker Socket: %v", dockerSocket)
+	}
+	if mtu != "" {
+		logger.Debug("MTU: %v", mtu)
+	}
+	if updownScript != "" {
+		logger.Debug("Up Down Script: %v", updownScript)
+	}
+
 	// Create TUN device and network stack
 	var tun tun.Device
 	var tnet *netstack.Net
@@ -689,7 +721,7 @@ persistent_keepalive_interval=5`, fixKey(privateKey.String()), fixKey(wgData.Pub
 		}
 
 		// List Docker containers
-		containers, err := docker.ListContainers(dockerSocket, dockerContainerAsHostnameBool)
+		containers, err := docker.ListContainers(dockerSocket, dockerEnforceNetworkValidationBool, dockerContainerAsHostnameBool)
 		if err != nil {
 			logger.Error("Failed to list Docker containers: %v", err)
 			return
@@ -798,9 +830,15 @@ func updateTargets(pm *proxy.ProxyManager, action string, tunnelIP string, proto
 			}
 
 			// Add the new target
-			isWithinNewtNetwork, err := docker.IsWithinNewtNetwork(dockerSocket, dockerContainerAsHostnameBool, targetAddress, targetPort)
-			if !isWithinNewtNetwork {
-				logger.Error("Not adding target: %v", err)
+			if dockerEnforceNetworkValidationBool {
+				logger.Info("Enforcing docker network validation")
+
+				isWithinNewtNetwork, err := docker.IsWithinNewtNetwork(dockerSocket, dockerContainerAsHostnameBool, targetAddress, targetPort)
+				if !isWithinNewtNetwork {
+					logger.Error("Not adding target: %v", err)
+				} else {
+					pm.AddTarget(proto, tunnelIP, port, processedTarget)
+				}
 			} else {
 				pm.AddTarget(proto, tunnelIP, port, processedTarget)
 			}