fact: add ip utils library & add unit testing

Consolidate IP utility functions into a new file and add proper unit
testing. Additionally consolidate logic and references to default route
subnets.

Author: aauren

pkg/controllers/proxy/linux_networking.go

@@ -23,10 +23,8 @@ import (
 )
 
 const (
-	ipv4NetMaskBits  = 32
-	ipv4DefaultRoute = "0.0.0.0/0"
-	ipv6NetMaskBits  = 128
-	ipv6DefaultRoute = "::/0"
+	ipv4NetMaskBits = 32
+	ipv6NetMaskBits = 128
 
 	// TODO: it's bad to rely on eth0 here. While this is inside the container's namespace and is determined by the
 	// container runtime and so far we've been able to count on this being reliably set to eth0, it is possible that
@@ -498,10 +496,10 @@ func (ln *linuxNetworking) setupPolicyRoutingForDSR(setupIPv4, setupIPv6 bool) e
 
 	if setupIPv4 {
 		nFamily := netlink.FAMILY_V4
-		_, defaultRouteCIDR, err := net.ParseCIDR(ipv4DefaultRoute)
-		if err != nil {
+		defaultRouteCIDR := utils.GetDefaultIPv4Route()
+		if defaultRouteCIDR == nil {
 			return fmt.Errorf("failed to parse default (%s) route (this is statically defined, so if you see this "+
-				"error please report because something has gone very wrong) due to: %v", ipv4DefaultRoute, err)
+				"error please report because something has gone very wrong)", defaultRouteCIDR)
 		}
 		nRoute := &netlink.Route{
 			Family:    nFamily,
@@ -520,10 +518,10 @@ func (ln *linuxNetworking) setupPolicyRoutingForDSR(setupIPv4, setupIPv6 bool) e
 
 	if setupIPv6 {
 		nFamily := netlink.FAMILY_V6
-		_, defaultRouteCIDR, err := net.ParseCIDR(ipv6DefaultRoute)
-		if err != nil {
+		defaultRouteCIDR := utils.GetDefaultIPv6Route()
+		if defaultRouteCIDR == nil {
 			return fmt.Errorf("failed to parse default (%s) route (this is statically defined, so if you see this "+
-				"error please report because something has gone very wrong) due to: %v", ipv6DefaultRoute, err)
+				"error please report because something has gone very wrong)", defaultRouteCIDR)
 		}
 		nRoute := &netlink.Route{
 			Family:    nFamily,
@@ -556,14 +554,14 @@ func (ln *linuxNetworking) setupRoutesForExternalIPForDSR(serviceInfoMap service
 
 	setupIPRulesAndRoutes := func(isIPv6 bool) error {
 		nFamily := netlink.FAMILY_V4
-		_, defaultPrefixCIDR, err := net.ParseCIDR(ipv4DefaultRoute)
+		defaultPrefixCIDR := utils.GetDefaultIPv4Route()
 		if isIPv6 {
 			nFamily = netlink.FAMILY_V6
-			_, defaultPrefixCIDR, err = net.ParseCIDR(ipv6DefaultRoute)
+			defaultPrefixCIDR = utils.GetDefaultIPv6Route()
 		}
-		if err != nil {
-			return fmt.Errorf("failed to parse default route (this is statically defined, so if you see this "+
-				"error please report because something has gone very wrong) due to: %v", err)
+		if defaultPrefixCIDR == nil {
+			return fmt.Errorf("failed to parse default route (this is statically defined, so if you see this " +
+				"error please report because something has gone very wrong)")
 		}
 
 		nRule := netlink.NewRule()

pkg/controllers/routing/bgp_policies.go

@@ -278,8 +278,8 @@ func (nrc *NetworkRoutingController) addServiceVIPsDefinedSet() error {
 // create a defined set to represent just the host default route
 func (nrc *NetworkRoutingController) addDefaultRouteDefinedSet() error {
 	for setName, defaultRoute := range map[string]string{
-		defaultRouteSet:   "0.0.0.0/0",
-		defaultRouteSetV6: "::/0",
+		defaultRouteSet:   utils.IPv4DefaultRoute,
+		defaultRouteSetV6: utils.IPv6DefaultRoute,
 	} {
 		currentDefinedSet, err := nrc.getDefinedSetFromGoBGP(setName, gobgpapi.DefinedType_PREFIX)
 		if err != nil {

pkg/utils/ip.go

@@ -0,0 +1,88 @@
+package utils
+
+import (
+	"bytes"
+	"fmt"
+	"net"
+)
+
+const (
+	IPv4DefaultRoute = "0.0.0.0/0"
+	IPv6DefaultRoute = "::/0"
+)
+
+// ContainsIPv4Address checks a given string array to see if it contains a valid IPv4 address within it
+func ContainsIPv4Address(addrs []string) bool {
+	for _, addr := range addrs {
+		ip := net.ParseIP(addr)
+		if ip == nil {
+			continue
+		}
+		if ip.To4() != nil {
+			return true
+		}
+	}
+	return false
+}
+
+// ContainsIPv6Address checks a given string array to see if it contains a valid IPv6 address within it
+func ContainsIPv6Address(addrs []string) bool {
+	for _, addr := range addrs {
+		ip := net.ParseIP(addr)
+		if ip == nil {
+			continue
+		}
+		if ip.To4() != nil {
+			continue
+		}
+		if ip.To16() != nil {
+			return true
+		}
+	}
+	return false
+}
+
+// GetDefaultIPv4Route returns the default IPv4 route
+func GetDefaultIPv4Route() *net.IPNet {
+	_, defaultPrefixCIDR, err := net.ParseCIDR(IPv4DefaultRoute)
+	if err != nil {
+		return nil
+	}
+	return defaultPrefixCIDR
+}
+
+// GetDefaultIPv6Route returns the default IPv6 route
+func GetDefaultIPv6Route() *net.IPNet {
+	_, defaultPrefixCIDR, err := net.ParseCIDR(IPv6DefaultRoute)
+	if err != nil {
+		return nil
+	}
+	return defaultPrefixCIDR
+}
+
+// IPNetEqual checks if two IPNet objects are equal by comparing the IP and Mask
+func IPNetEqual(a, b *net.IPNet) bool {
+	if a == nil || b == nil {
+		return a == b
+	}
+	return a.IP.Equal(b.IP) && bytes.Equal(a.Mask, b.Mask)
+}
+
+// IsDefaultRoute checks if a given CIDR is a default route by comparing it to the default routes for IPv4 and IPv6
+func IsDefaultRoute(cidr *net.IPNet) (bool, error) {
+	var defaultPrefixCIDR *net.IPNet
+	var err error
+
+	if cidr.IP.To4() != nil {
+		_, defaultPrefixCIDR, err = net.ParseCIDR(IPv4DefaultRoute)
+		if err != nil {
+			return false, fmt.Errorf("failed to parse default route: %s", err.Error())
+		}
+	} else {
+		_, defaultPrefixCIDR, err = net.ParseCIDR(IPv6DefaultRoute)
+		if err != nil {
+			return false, fmt.Errorf("failed to parse default route: %s", err.Error())
+		}
+	}
+	return IPNetEqual(defaultPrefixCIDR, cidr), nil
+}