Fix when connecting/disconnecting to/from default gw network

- Restoring original behavior where on disconnect
  from overlay network (only connected network), it also
  disconnects from default gw network.
- On sandbox delete, the leave and delete of each
  endpoint is performed, regardless of whether the endpoint
  is the gw network endpoint. This endpoint is already
  automatically removed in endpoint.sbLeave()
- Also do not let internal network dictate container does
  not need external connectivity. Before this fix, if a container
  was connected to an overlay and an internal network, it may not
  get attached to the default gw network.

Signed-off-by: Alessandro Boch <aboch@docker.com>

libnetwork/default_gateway.go

@@ -65,20 +65,13 @@ func (sb *sandbox) setupDefaultGW() error {
 	return nil
 }
 
-// If present, removes the endpoint connecting the sandbox to the default gw network.
-// Unless it is the endpoint designated to provide the external connectivity.
-// If the sandbox is being deleted, removes the endpoint unconditionally.
+// If present, detach and remove the endpoint connecting the sandbox to the default gw network.
 func (sb *sandbox) clearDefaultGW() error {
 	var ep *endpoint
 
 	if ep = sb.getEndpointInGWNetwork(); ep == nil {
 		return nil
 	}
-
-	if ep == sb.getGatewayEndpoint() && !sb.inDelete {
-		return nil
-	}
-
 	if err := ep.sbLeave(sb, false); err != nil {
 		return fmt.Errorf("container %s: endpoint leaving GW Network failed: %v", sb.containerID, err)
 	}
@@ -88,21 +81,26 @@ func (sb *sandbox) clearDefaultGW() error {
 	return nil
 }
 
+// Evaluate whether the sandbox requires a default gateway based
+// on the endpoints to which it is connected. It does not account
+// for the default gateway network endpoint.
+
 func (sb *sandbox) needDefaultGW() bool {
 	var needGW bool
 
 	for _, ep := range sb.getConnectedEndpoints() {
 		if ep.endpointInGWNetwork() {
-			return false
+			continue
 		}
 		if ep.getNetwork().Type() == "null" || ep.getNetwork().Type() == "host" {
 			continue
 		}
 		if ep.getNetwork().Internal() {
-			return false
+			continue
 		}
-		if ep.joinInfo.disableGatewayService {
-			return false
+		// During stale sandbox cleanup, joinInfo may be nil
+		if ep.joinInfo != nil && ep.joinInfo.disableGatewayService {
+			continue
 		}
 		// TODO v6 needs to be handled.
 		if len(ep.Gateway()) > 0 {
@@ -115,6 +113,7 @@ func (sb *sandbox) needDefaultGW() bool {
 		}
 		needGW = true
 	}
+
 	return needGW
 }
 

libnetwork/endpoint.go

@@ -446,7 +446,7 @@ func (ep *endpoint) sbJoin(sb *sandbox, options ...EndpointOption) error {
 		return err
 	}
 
-	if sb.needDefaultGW() {
+	if sb.needDefaultGW() && sb.getEndpointInGWNetwork() == nil {
 		return sb.setupDefaultGW()
 	}
 
@@ -479,7 +479,14 @@ func (ep *endpoint) sbJoin(sb *sandbox, options ...EndpointOption) error {
 		}
 	}
 
-	return sb.clearDefaultGW()
+	if !sb.needDefaultGW() {
+		if err := sb.clearDefaultGW(); err != nil {
+			log.Warnf("Failure while disconnecting sandbox %s (%s) from gateway network: %v",
+				sb.ID(), sb.ContainerID(), err)
+		}
+	}
+
+	return nil
 }
 
 func (ep *endpoint) rename(name string) error {
@@ -622,10 +629,7 @@ func (ep *endpoint) sbLeave(sb *sandbox, force bool, options ...EndpointOption)
 	}
 
 	sb.deleteHostsEntries(n.getSvcRecords(ep))
-	if !sb.inDelete && sb.needDefaultGW() {
-		if sb.getEPwithoutGateway() == nil {
-			return fmt.Errorf("endpoint without GW expected, but not found")
-		}
+	if !sb.inDelete && sb.needDefaultGW() && sb.getEndpointInGWNetwork() == nil {
 		return sb.setupDefaultGW()
 	}
 
@@ -639,7 +643,14 @@ func (ep *endpoint) sbLeave(sb *sandbox, force bool, options ...EndpointOption)
 		}
 	}
 
-	return sb.clearDefaultGW()
+	if !sb.needDefaultGW() {
+		if err := sb.clearDefaultGW(); err != nil {
+			log.Warnf("Failure while disconnecting sandbox %s (%s) from gateway network: %v",
+				sb.ID(), sb.ContainerID(), err)
+		}
+	}
+
+	return nil
 }
 
 func (n *network) validateForceDelete(locator string) error {

libnetwork/sandbox.go

@@ -197,6 +197,10 @@ func (sb *sandbox) delete(force bool) error {
 	// Detach from all endpoints
 	retain := false
 	for _, ep := range sb.getConnectedEndpoints() {
+		// gw network endpoint detach and removal are automatic
+		if ep.endpointInGWNetwork() {
+			continue
+		}
 		// Retain the sanbdox if we can't obtain the network from store.
 		if _, err := c.getNetworkFromStore(ep.getNetwork().ID()); err != nil {
 			retain = true

libnetwork/test/integration/dnet/helpers.bash

@@ -345,10 +345,6 @@ function test_overlay() {
             # Disconnect from overlay network
             net_disconnect ${start} container_${start} multihost
 
-            # Make sure external connectivity works
-            runc $(dnet_container_name ${start} $dnet_suffix) $(get_sbox_id ${start} container_${start}) \
-                "ping -c 1 www.google.com"
-
             # Connect to overlay network again
             net_connect ${start} container_${start} multihost