Add netdev subcommands to weaveutil

The subcommands are going to be used with WithNetNS wrapper.

common/utils.go

@@ -76,7 +76,7 @@ func forEachLink(f func(netlink.Link) error) error {
 	return nil
 }
 
-func linkToNetDev(link netlink.Link) (NetDev, error) {
+func LinkToNetDev(link netlink.Link) (NetDev, error) {
 	addrs, err := netlink.AddrList(link, netlink.FAMILY_V4)
 	if err != nil {
 		return NetDev{}, err
@@ -164,5 +164,5 @@ func GetBridgeNetDev(bridgeName string) (NetDev, error) {
 		return NetDev{}, err
 	}
 
-	return linkToNetDev(link)
+	return LinkToNetDev(link)
 }

prog/weaveutil/main.go

@@ -24,6 +24,10 @@ func init() {
 		"attach-container":       attach,
 		"detach-container":       detach,
 		"configure-arp":          configureARP,
+		"check-iface":            checkIface,
+		"del-iface":              delIface,
+		"setup-iface":            setupIface,
+		"list-netdevs":           listNetDevs,
 	}
 }
 

prog/weaveutil/netdev.go

@@ -1,14 +1,75 @@
 package main
 
 import (
+	"fmt"
+	"strconv"
 	"strings"
 
+	"github.com/coreos/go-iptables/iptables"
 	"github.com/j-keck/arping"
 	"github.com/vishvananda/netlink"
 
+	"github.com/weaveworks/weave/common"
 	weavenet "github.com/weaveworks/weave/net"
 )
 
+// checkIface returns an error if the given interface cannot be found.
+func checkIface(args []string) error {
+	if len(args) != 1 {
+		cmdUsage("check-iface", "<iface-name>")
+	}
+	ifaceName := args[0]
+
+	if _, err := netlink.LinkByName(ifaceName); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func delIface(args []string) error {
+	if len(args) != 1 {
+		cmdUsage("del-iface", "<iface-name>")
+	}
+	ifName := args[0]
+
+	link, err := netlink.LinkByName(ifName)
+	if err != nil {
+		return err
+	}
+	return netlink.LinkDel(link)
+}
+
+// setupIface renames the given iface and configures its ARP cache settings.
+func setupIface(args []string) error {
+	if len(args) != 2 {
+		cmdUsage("setup-iface", "<iface-name> <new-iface-name>")
+	}
+	ifaceName := args[0]
+	newIfName := args[1]
+
+	ipt, err := iptables.New()
+	if err != nil {
+		return err
+	}
+
+	link, err := netlink.LinkByName(ifaceName)
+	if err != nil {
+		return err
+	}
+	if err := netlink.LinkSetName(link, newIfName); err != nil {
+		return err
+	}
+	if err := weavenet.ConfigureARPCache(newIfName); err != nil {
+		return err
+	}
+	if err := ipt.Append("filter", "INPUT", "-i", newIfName, "-d", "224.0.0.0/4", "-j", "DROP"); err != nil {
+		return err
+	}
+
+	return nil
+}
+
 func configureARP(args []string) error {
 	if len(args) != 1 {
 		cmdUsage("configure-arp", "<iface-name-prefix>")
@@ -33,3 +94,39 @@ func configureARP(args []string) error {
 
 	return nil
 }
+
+// listNetDevs outputs network ifaces identified by the given indexes
+// in the format of weavenet.Dev.
+func listNetDevs(args []string) error {
+	if len(args) != 1 {
+		cmdUsage("list-netdevs", "<iface-index>[,<iface-index>]")
+	}
+
+	indexes := make(map[int]struct{})
+	for _, index := range strings.Split(args[0], ",") {
+		if index != "" {
+			id, err := strconv.Atoi(index)
+			if err != nil {
+				return err
+			}
+			indexes[id] = struct{}{}
+		}
+	}
+
+	links, err := netlink.LinkList()
+	if err != nil {
+		return err
+	}
+
+	for _, link := range links {
+		if _, found := indexes[link.Attrs().Index]; found {
+			netdev, err := common.LinkToNetDev(link)
+			if err != nil {
+				return err
+			}
+			fmt.Println(netdev)
+		}
+	}
+
+	return nil
+}