IPv6: add iputil package, filter ips by version 4 when looking up underlayIPs interface names

Author: plamen-bardarov

src/code.cloudfoundry.org/cni-wrapper-plugin/main.go

@@ -19,6 +19,7 @@ import (
 	"code.cloudfoundry.org/lib/common"
 	"code.cloudfoundry.org/lib/datastore"
 	"code.cloudfoundry.org/lib/interfacelookup"
+	"code.cloudfoundry.org/lib/iputil"
 	"code.cloudfoundry.org/lib/rules"
 	"code.cloudfoundry.org/lib/serial"
 	"github.com/containernetworking/cni/pkg/skel"
@@ -149,7 +150,8 @@ func cmdAdd(args *skel.CmdArgs) error {
 	if len(cfg.TemporaryUnderlayInterfaceNames) > 0 {
 		interfaceNames = cfg.TemporaryUnderlayInterfaceNames
 	} else {
-		interfaceNames, err = interfaceNameLookup.GetNamesFromIPs(cfg.UnderlayIPs)
+		v4UnderlayIps, _ := iputil.FilterIPsByVersion(cfg.UnderlayIPs, iputil.IPVersion4)
+		interfaceNames, err = interfaceNameLookup.GetNamesFromIPs(v4UnderlayIps)
 		if err != nil {
 			return fmt.Errorf("looking up interface names: %s", err) // not tested
 		}
@@ -427,14 +429,12 @@ func cmdDel(args *skel.CmdArgs) error {
 		NetlinkAdapter: &adapter.NetlinkAdapter{},
 	}
 
-	// TODO: The way cfg.UnderlayIPs is populated is from bosh spec.networks. This will be a problem if there are ipv6 networks there
-	// because we will not be able to find the interface name for ipv6 networks and error will be returned.
-	// Should be fixed in the future when theres a working bosh ipv6 implementation
 	var interfaceNames []string
 	if len(cfg.TemporaryUnderlayInterfaceNames) > 0 {
 		interfaceNames = cfg.TemporaryUnderlayInterfaceNames
 	} else {
-		interfaceNames, err = interfaceNameLookup.GetNamesFromIPs(cfg.UnderlayIPs)
+		v4UnderlayIps, _ := iputil.FilterIPsByVersion(cfg.UnderlayIPs, iputil.IPVersion4)
+		interfaceNames, err = interfaceNameLookup.GetNamesFromIPs(v4UnderlayIps)
 		if err != nil {
 			return fmt.Errorf("looking up interface names: %s", err) // not tested
 		}

src/code.cloudfoundry.org/lib/interfacelookup/interface_name_lookup.go

@@ -23,6 +23,7 @@ type InterfaceNameLookup struct {
 	NetlinkAdapter netlinkAdapter
 }
 
+// GetNameFromIP Only works for IPv4 addresses
 func (i InterfaceNameLookup) GetNameFromIP(ip string) (string, error) {
 	links, err := common.RetryWithBackoff(retryInterval, maxRetries, func() ([]netlink.Link, error) {
 		return i.NetlinkAdapter.LinkList()

src/code.cloudfoundry.org/lib/iputil/iputil.go

@@ -0,0 +1,46 @@
+package iputil
+
+import (
+	"fmt"
+	"net"
+)
+
+type IPVersion int
+
+const (
+	InvalidIPVersion IPVersion = iota
+	IPVersion4       IPVersion = 4
+	IPVersion6       IPVersion = 6
+)
+
+func GetFamily(ip net.IP) IPVersion {
+	if len(ip) == 0 {
+		return InvalidIPVersion
+	}
+	if ip.To4() != nil {
+		return IPVersion4
+	}
+	if ip.To16() != nil {
+		return IPVersion6
+	}
+	return InvalidIPVersion
+}
+
+func FilterIPsByVersion(ipStrs []string, version IPVersion) ([]string, error) {
+	filtered := make([]string, 0, len(ipStrs))
+
+	for _, str := range ipStrs {
+		ip := net.ParseIP(str)
+		if ip == nil {
+			return nil, fmt.Errorf("invalid IP string: %s", str)
+		}
+
+		family := GetFamily(ip)
+
+		if family == version {
+			filtered = append(filtered, str)
+		}
+	}
+
+	return filtered, nil
+}

src/code.cloudfoundry.org/vxlan-policy-agent/cmd/vxlan-policy-agent/main.go

@@ -4,7 +4,6 @@ import (
 	"flag"
 	"fmt"
 	"log"
-	"net"
 	"net/http"
 	"os"
 	"path/filepath"
@@ -18,6 +17,7 @@ import (
 	"code.cloudfoundry.org/lib/common"
 	"code.cloudfoundry.org/lib/datastore"
 	"code.cloudfoundry.org/lib/interfacelookup"
+	"code.cloudfoundry.org/lib/iputil"
 	"code.cloudfoundry.org/lib/rules"
 	"code.cloudfoundry.org/lib/serial"
 	"code.cloudfoundry.org/policy_client"
@@ -383,17 +383,7 @@ func createForceUpdateServer(listenAddress string, handlers map[string]http.Hand
 }
 
 func lookupInterfaceNames(lookup interfacelookup.InterfaceNameLookup, ips []string) ([]string, error) {
-	var ipsV4 []string
-	for _, ip := range ips {
-		parsed := net.ParseIP(ip)
-		if parsed == nil {
-			return nil, fmt.Errorf("invalid IP address: %s", ip)
-		}
-		if parsed.To4() != nil {
-			ipsV4 = append(ipsV4, ip)
-		}
-	}
-
+	ipsV4, _ := iputil.FilterIPsByVersion(ips, iputil.IPVersion4)
 	var v4names, err = lookup.GetNamesFromIPs(ipsV4)
 	if err != nil {
 		return nil, err