Maint: internal/subnet package

internal/subnet/subnets.go

@@ -0,0 +1,53 @@
+package subnet
+
+import (
+	"net"
+)
+
+func FindSubnetsToAdd(oldSubnets, newSubnets []net.IPNet) (subnetsToAdd []net.IPNet) {
+	for _, newSubnet := range newSubnets {
+		found := false
+		for _, oldSubnet := range oldSubnets {
+			if subnetsAreEqual(oldSubnet, newSubnet) {
+				found = true
+				break
+			}
+		}
+		if !found {
+			subnetsToAdd = append(subnetsToAdd, newSubnet)
+		}
+	}
+	return subnetsToAdd
+}
+
+func FindSubnetsToRemove(oldSubnets, newSubnets []net.IPNet) (subnetsToRemove []net.IPNet) {
+	for _, oldSubnet := range oldSubnets {
+		found := false
+		for _, newSubnet := range newSubnets {
+			if subnetsAreEqual(oldSubnet, newSubnet) {
+				found = true
+				break
+			}
+		}
+		if !found {
+			subnetsToRemove = append(subnetsToRemove, oldSubnet)
+		}
+	}
+	return subnetsToRemove
+}
+
+func subnetsAreEqual(a, b net.IPNet) bool {
+	return a.IP.Equal(b.IP) && a.Mask.String() == b.Mask.String()
+}
+
+func RemoveSubnetFromSubnets(subnets []net.IPNet, subnet net.IPNet) []net.IPNet {
+	L := len(subnets)
+	for i := range subnets {
+		if subnetsAreEqual(subnet, subnets[i]) {
+			subnets[i] = subnets[L-1]
+			subnets = subnets[:L-1]
+			break
+		}
+	}
+	return subnets
+}