Use existing interface to request IP address during restore

The initial implementation to request the same IP address for a
container during a restore was based on environment variables
influencing CNI.

With this commit the IP address selection switches to Podman's internal
static IP API.

This commit does a comment change in libpod/container_easyjson.go to
avoid unnecessary re-generation of libpod/container_easyjson.go during
build as this fails in CI. The reason for this is that make sees that
libpod/container_easyjson.go needs to be re-created. The commit,
however, only changes a part of libpod/container.go which is marked as
'ffjson: skip'.

Signed-off-by: Adrian Reber <areber@redhat.com>

libpod/container.go

@@ -128,6 +128,11 @@ type Container struct {
 
 	rootlessSlirpSyncR *os.File
 	rootlessSlirpSyncW *os.File
+
+	// A restored container should have the same IP address as before
+	// being checkpointed. If requestedIP is set it will be used instead
+	// of config.StaticIP.
+	requestedIP net.IP
 }
 
 // containerState contains the current state of the container

libpod/container_easyjson.go

@@ -1,6 +1,6 @@
 // +build  seccomp   ostree selinux  varlink exclude_graphdriver_devicemapper
 
-// Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT.
+// Code generated by easyjson for marshaling/unmarshaling. DO NOT EDIT
 
 package libpod
 

libpod/container_internal_linux.go

@@ -547,10 +547,8 @@ func (c *Container) restore(ctx context.Context, options ContainerCheckpointOpti
 			}
 		}
 		if IP != nil {
-			env := fmt.Sprintf("IP=%s", IP)
 			// Tell CNI which IP address we want.
-			os.Setenv("CNI_ARGS", env)
-			logrus.Debugf("Restoring container with %s", env)
+			c.requestedIP = IP
 		}
 	}
 
@@ -566,12 +564,6 @@ func (c *Container) restore(ctx context.Context, options ContainerCheckpointOpti
 		return err
 	}
 
-	// TODO: use existing way to request static IPs, once it is merged in ocicni
-	// https://github.com/cri-o/ocicni/pull/23/
-
-	// CNI_ARGS was used to request a certain IP address. Unconditionally remove it.
-	os.Unsetenv("CNI_ARGS")
-
 	// Read config
 	jsonPath := filepath.Join(c.bundlePath(), "config.json")
 	logrus.Debugf("generate.NewFromFile at %v", jsonPath)

libpod/networking_linux.go

@@ -50,7 +50,16 @@ func (r *Runtime) getPodNetwork(id, name, nsPath string, networks []string, port
 
 // Create and configure a new network namespace for a container
 func (r *Runtime) configureNetNS(ctr *Container, ctrNS ns.NetNS) ([]*cnitypes.Result, error) {
-	podNetwork := r.getPodNetwork(ctr.ID(), ctr.Name(), ctrNS.Path(), ctr.config.Networks, ctr.config.PortMappings, ctr.config.StaticIP)
+	var requestedIP net.IP
+	if ctr.requestedIP != nil {
+		requestedIP = ctr.requestedIP
+		// cancel request for a specific IP in case the container is reused later
+		ctr.requestedIP = nil
+	} else {
+		requestedIP = ctr.config.StaticIP
+	}
+
+	podNetwork := r.getPodNetwork(ctr.ID(), ctr.Name(), ctrNS.Path(), ctr.config.Networks, ctr.config.PortMappings, requestedIP)
 
 	results, err := r.netPlugin.SetUpPod(podNetwork)
 	if err != nil {
@@ -258,7 +267,16 @@ func (r *Runtime) teardownNetNS(ctr *Container) error {
 
 	logrus.Debugf("Tearing down network namespace at %s for container %s", ctr.state.NetNS.Path(), ctr.ID())
 
-	podNetwork := r.getPodNetwork(ctr.ID(), ctr.Name(), ctr.state.NetNS.Path(), ctr.config.Networks, ctr.config.PortMappings, ctr.config.StaticIP)
+	var requestedIP net.IP
+	if ctr.requestedIP != nil {
+		requestedIP = ctr.requestedIP
+		// cancel request for a specific IP in case the container is reused later
+		ctr.requestedIP = nil
+	} else {
+		requestedIP = ctr.config.StaticIP
+	}
+
+	podNetwork := r.getPodNetwork(ctr.ID(), ctr.Name(), ctr.state.NetNS.Path(), ctr.config.Networks, ctr.config.PortMappings, requestedIP)
 
 	// The network may have already been torn down, so don't fail here, just log
 	if err := r.netPlugin.TearDownPod(podNetwork); err != nil {