[proxy] support new docker 1.8 --net="default"

proxy/proxy.go

@@ -25,9 +25,8 @@ var (
 	containerStartRegexp  = regexp.MustCompile("^(/v[0-9\\.]*)?/containers/[^/]*/(re)?start$")
 	execCreateRegexp      = regexp.MustCompile("^(/v[0-9\\.]*)?/containers/[^/]*/exec$")
 
-	ErrInvalidNetworkMode = errors.New("--net option")
-	ErrWeaveCIDRNone      = errors.New("WEAVE_CIDR=none")
-	ErrNoDefaultIPAM      = errors.New("--no-default-ipam option")
+	ErrWeaveCIDRNone = errors.New("WEAVE_CIDR=none")
+	ErrNoDefaultIPAM = errors.New("--no-default-ipam option")
 )
 
 type Proxy struct {
@@ -152,8 +151,9 @@ func (proxy *Proxy) ListenAndServe() error {
 func (proxy *Proxy) weaveCIDRsFromConfig(config *docker.Config, hostConfig *docker.HostConfig) ([]string, error) {
 	if hostConfig != nil &&
 		hostConfig.NetworkMode != "" &&
+		hostConfig.NetworkMode != "default" &&
 		hostConfig.NetworkMode != "bridge" {
-		return nil, ErrInvalidNetworkMode
+		return nil, fmt.Errorf("--net option: %q", hostConfig.NetworkMode)
 	}
 	for _, e := range config.Env {
 		if strings.HasPrefix(e, "WEAVE_CIDR=") {