initial commit

internal/common/iputil.go

@@ -0,0 +1,37 @@
+package common
+
+import "net"
+
+// BroadcastAddr returns the last address in the given network, or the broadcast address.
+func BroadcastAddr(n *net.IPNet) net.IP {
+	// The golang net package doesn't make it easy to calculate the broadcast address. :(
+	var broadcast net.IP
+	if len(n.IP) == 4 {
+		broadcast = net.ParseIP("0.0.0.0").To4()
+	} else {
+		broadcast = net.ParseIP("::")
+	}
+	for i := 0; i < len(n.IP); i++ {
+		broadcast[i] = n.IP[i] | ^n.Mask[i]
+	}
+	return broadcast
+}
+
+//  http://play.golang.org/p/m8TNTtygK0
+func IncreaseIP(ip net.IP) {
+	for j := len(ip) - 1; j >= 0; j-- {
+		ip[j]++
+		if ip[j] > 0 {
+			break
+		}
+	}
+}
+
+// IsIPv6 check if given ip is IPv6
+func IsIPv6(address string) bool {
+	ip := net.ParseIP(address)
+	if ip == nil {
+		return false
+	}
+	return ip.To4() == nil
+}