net: call ipam plugin on container shutdown

- Fixes bugs in ipam/static release path
- veth and bridge plugins invoke ipam plugin during DEL cmd

networking/ipam/ipam.go

@@ -94,7 +94,13 @@ func findIPAMPlugin(plugin string) string {
 	return ""
 }
 
-func ExecPlugin(plugin string) (*IPConfig, error) {
+// Executes IPAM plugin, assuming RKT_NETPLUGIN_COMMAND == ADD.
+// Parses and returns resulting IPConfig
+func ExecPluginAdd(plugin string) (*IPConfig, error) {
+	if os.Getenv("RKT_NETPLUGIN_COMMAND") != "ADD" {
+		return nil, fmt.Errorf("RKT_NETPLUGIN_COMMAND is not ADD")
+	}
+
 	pluginPath := findIPAMPlugin(plugin)
 	if pluginPath == "" {
 		return nil, fmt.Errorf("could not find %q plugin", plugin)
@@ -117,6 +123,25 @@ func ExecPlugin(plugin string) (*IPConfig, error) {
 	return ipConf, err
 }
 
+// Executes IPAM plugin, assuming RKT_NETPLUGIN_COMMAND == DEL.
+func ExecPluginDel(plugin string) error {
+	if os.Getenv("RKT_NETPLUGIN_COMMAND") != "DEL" {
+		return fmt.Errorf("RKT_NETPLUGIN_COMMAND is not DEL")
+	}
+
+	pluginPath := findIPAMPlugin(plugin)
+	if pluginPath == "" {
+		return fmt.Errorf("could not find %q plugin", plugin)
+	}
+
+	c := exec.Cmd{
+		Path:   pluginPath,
+		Args:   []string{pluginPath},
+		Stderr: os.Stderr,
+	}
+	return c.Run()
+}
+
 func ApplyIPConfig(ifName string, ipConf *IPConfig) error {
 	link, err := netlink.LinkByName(ifName)
 	if err != nil {

networking/ipam/static/backend/disk/backend.go

@@ -58,21 +58,20 @@ func (s *Store) Release(ip net.IP) error {
 	return os.Remove(filepath.Join(s.dataDir, ip.String()))
 }
 
+// N.B. This function eats errors to be tolerant and
+// release as much as possible
 func (s *Store) ReleaseByContainerID(id string) error {
 	err := filepath.Walk(s.dataDir, func(path string, info os.FileInfo, err error) error {
-		if err != nil {
-			return err
-		}
-		if info.IsDir() && path != s.dataDir {
+		if err != nil || info.IsDir() {
 			return nil
 		}
 		data, err := ioutil.ReadFile(path)
 		if err != nil {
-			return err
+			return nil
 		}
 		if string(data) == id {
 			if err := os.Remove(path); err != nil {
-				return err
+				return nil
 			}
 		}
 		return nil

networking/net/bridge/bridge.go

@@ -45,6 +45,16 @@ func init() {
 	runtime.LockOSThread()
 }
 
+func loadConf(path string) (*Net, error) {
+	n := &Net{
+		BrName: defaultBrName,
+	}
+	if err := rktnet.LoadNet(path, n); err != nil {
+		return nil, fmt.Errorf("failed to load %q: %v", path, err)
+	}
+	return n, nil
+}
+
 func ensureBridgeAddr(br *netlink.Bridge, ipn *net.IPNet) error {
 	addrs, err := netlink.AddrList(br, syscall.AF_INET)
 	if err != nil && err != syscall.ENOENT {
@@ -183,15 +193,13 @@ func cmdAdd(contID, netns, netConf, ifName string) error {
 		return fmt.Errorf("error parsing ContainerID: %v", err)
 	}
 
-	n := &Net{
-		BrName: defaultBrName,
-	}
-	if err := rktnet.LoadNet(netConf, n); err != nil {
-		return fmt.Errorf("failed to load %q: %v", netConf, err)
+	n, err := loadConf(netConf)
+	if err != nil {
+		return err
 	}
 
 	// run the IPAM plugin and get back the config to apply
-	ipConf, err := ipam.ExecPlugin(n.Net.IPAM.Type)
+	ipConf, err := ipam.ExecPluginAdd(n.Net.IPAM.Type)
 	if err != nil {
 		return err
 	}
@@ -211,9 +219,19 @@ func cmdAdd(contID, netns, netConf, ifName string) error {
 }
 
 func cmdDel(contID, netns, netConf, ifName string) error {
-	return util.WithNetNSPath(netns, func(hostNS *os.File) error {
+	n, err := loadConf(netConf)
+	if err != nil {
+		return err
+	}
+
+	err = util.WithNetNSPath(netns, func(hostNS *os.File) error {
 		return util.DelLinkByName(ifName)
 	})
+	if err != nil {
+		return err
+	}
+
+	return ipam.ExecPluginDel(n.Net.IPAM.Type)
 }
 
 func main() {

networking/net/veth/veth.go

@@ -44,7 +44,7 @@ func cmdAdd(contID, netns, netConf, ifName, args string) error {
 	}
 
 	// run the IPAM plugin and get back the config to apply
-	ipConf, err := ipam.ExecPlugin(conf.IPAM.Type)
+	ipConf, err := ipam.ExecPluginAdd(conf.IPAM.Type)
 	if err != nil {
 		return err
 	}
@@ -96,9 +96,19 @@ func cmdAdd(contID, netns, netConf, ifName, args string) error {
 }
 
 func cmdDel(contID, netns, netConf, ifName, args string) error {
-	return util.WithNetNSPath(netns, func(hostNS *os.File) error {
+	conf := rktnet.Net{}
+	if err := rktnet.LoadNet(netConf, &conf); err != nil {
+		return fmt.Errorf("failed to load %q: %v", netConf, err)
+	}
+
+	err := util.WithNetNSPath(netns, func(hostNS *os.File) error {
 		return util.DelLinkByName(ifName)
 	})
+	if err != nil {
+		return err
+	}
+
+	return ipam.ExecPluginDel(conf.IPAM.Type)
 }
 
 func main() {

networking/networking.go

@@ -182,7 +182,7 @@ func (e *containerEnv) setupNets(netns string, nets []Net) ([]activeNet, error)
 			ifName: fmt.Sprintf(ifnamePattern, i),
 		}
 
-		log.Printf("Executing net-plugin %v", nt.Type)
+		log.Printf("Setup: executing net-plugin %v", nt.Type)
 
 		an.ip, err = e.netPluginAdd(&nt, netns, nt.args, an.ifName)
 		if err != nil {
@@ -193,8 +193,6 @@ func (e *containerEnv) setupNets(netns string, nets []Net) ([]activeNet, error)
 		active = append(active, an)
 	}
 
-	log.Print("Done executing net plugins")
-
 	if err != nil {
 		e.teardownNets(netns, active)
 		return nil, err
@@ -206,6 +204,8 @@ func (e *containerEnv) setupNets(netns string, nets []Net) ([]activeNet, error)
 func (e *containerEnv) teardownNets(netns string, nets []activeNet) {
 	for i := len(nets) - 1; i >= 0; i-- {
 		nt := nets[i]
+
+		log.Printf("Teardown: executing net-plugin %v", nt.Type)
 		err := e.netPluginDel(&nt.Net, netns, nt.args, nt.ifName)
 		if err != nil {
 			log.Printf("Error deleting %q: %v", nt.Name, err)