Merge pull request #14 from nerdalert/init_nets

Initialize existing networks

Author: dave-tucker

Diff for: README.md

@@ -56,10 +56,12 @@ honoring docker network opts yet.
 
 In the repo directory, use the binary named `macvlan-docker-plugin-0.3-Linux-x86_64`. Feel free to rename it :)
 
+**Note**: There is no need to add any paramters to the plugin daemon (other then `-d` debug for example). All options are passed via native Docker commands.
+
 ```
 $ git clone https://github.com/gopher-net/macvlan-docker-plugin.git
 $ cd macvlan-docker-plugin/binaries
-$ ./macvlan-docker-plugin-0.3-Linux-x86_64 -d --host-interface=eth1 --mode=bridge
+$ ./macvlan-docker-plugin-0.3-Linux-x86_64 -d
 
 # -d is debug
 # --host-interface is the master interface, eth0, eth1 etc. The docker network create needs to correspond to that subnet for bridge mode

Diff for: plugin/macvlan/driver.go

@@ -71,9 +71,12 @@ func New(version string, ctx *cli.Context) (Driver, error) {
 			client: docker,
 		},
 	}
+	// Init any existing libnetwork networks
+	d.existingNetChecks()
 	return d, nil
 }
 
+// Listen for callbacks on socket file handle /var/run/docker/plugins/macvlan.sock
 func (driver *driver) Listen(socket string) error {
 	router := mux.NewRouter()
 	router.NotFoundHandler = http.HandlerFunc(notFound)
@@ -163,6 +166,45 @@ func (driver *driver) capabilities(w http.ResponseWriter, r *http.Request) {
 	log.Debug("Capabilities exchange complete")
 }
 
+// existingNetChecks checks for networks that already exist in libnetwork cache
+func (driver *driver) existingNetChecks() {
+	// Request all networks on the endpoint without any filters
+	existingNets, err := driver.client.ListNetworks("")
+	if err != nil {
+		log.Errorf("unable to retrieve existing networks: %v", err)
+	}
+	var netCidr *net.IPNet
+	var netGW string
+	for _, n := range existingNets {
+		// Exclude the default network names
+		if n.Name != "" && n.Name != "none" && n.Name != "host" && n.Name != "bridge" {
+			for _, v4 := range n.IPAM.Config {
+				netGW = v4.Gateway
+				netCidr, err = parseIPNet(v4.Subnet)
+				if err != nil {
+					log.Errorf("invalid cidr address in network [ %s ]: %v", v4.Subnet, err)
+				}
+			}
+			nw := &network{
+				id:        n.ID,
+				endpoints: endpointTable{},
+				cidr:      netCidr,
+				gateway:   netGW,
+			}
+			// Parse docker network -o opts
+			for k, v := range n.Options {
+				// Infer a macvlan network from required option
+				if k == "host_iface" {
+					nw.ifaceOpt = v
+					log.Debugf("Existing macvlan network exists: [Name:%s, Cidr:%s, Gateway:%s, Master Iface:%s]",
+						n.Name, netCidr.String(), netGW, nw.ifaceOpt)
+					driver.addNetwork(nw)
+				}
+			}
+		}
+	}
+}
+
 type networkCreate struct {
 	NetworkID string
 	Options   map[string]interface{}
@@ -380,7 +422,7 @@ func (driver *driver) joinEndpoint(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	if getID.ifaceOpt == "" {
-		log.Error("Required macvlan parent interface is missing, please recreate the network specifying the host_iface")
+		log.Error("Required macvlan parent interface is missing, please recreate the network specifying the -o host_iface=ethX")
 		return
 	}
 	// Get the link for the master index (Example: the docker host eth iface)

Diff for: plugin/macvlan/utils.go

@@ -37,6 +37,7 @@ func getIfaceAddr(name string) (*net.IPNet, error) {
 	return addrs[0].IPNet, nil
 }
 
+// setVlanMode set the macvlan mode, currently only bridge is supported since others are rarely deployed
 func setVlanMode(mode string) (netlink.MacvlanMode, error) {
 	switch mode {
 	case "private":
@@ -76,3 +77,12 @@ func validateHostIface(ifaceStr string) bool {
 	}
 	return true
 }
+
+// parseIPNet returns a net.IP from a network cidr in string representation
+func parseIPNet(s string) (*net.IPNet, error) {
+	ip, ipNet, err := net.ParseCIDR(s)
+	if err != nil {
+		return nil, err
+	}
+	return &net.IPNet{IP: ip, Mask: ipNet.Mask}, nil
+}