ipvx.go

// Package ipvx is a light-weight wrapper around the ipv4 and ipv6 packages, allowing
// applications to be more protocol agnostic.
//
// The Conn and PacketConn interfaces are largely drop-in replacements for the corresponding
// structs from the ipv6 package, and translate to ipv4 where needed.  Not all methods are
// implemented, where they seem to be tightly coupled to the specific IP version.
package ipvx

// A great deal more from ipv4 and ipv6 could be implemented here, requiring progressively
// more overhead in terms of translating struct fields between the v6 and v4 versions.

import "net"

// GetIP returns the IP address from addr.  If addr does not contain an IP address, returns nil.
// Supports *net.IPAddr, *net.IPNet, *net.TCPAddr, and *net.UDPAddr concrete types.
func GetIP(addr net.Addr) (ip net.IP) {
	switch ipaddr := addr.(type) {
	case *net.IPAddr:
		ip = ipaddr.IP
	case *net.IPNet:
		ip = ipaddr.IP
	case *net.TCPAddr:
		ip = ipaddr.IP
	case *net.UDPAddr:
		ip = ipaddr.IP
	}
	return
}

// Is4 returns true if addr represents an IPv4 address.
func Is4(addr net.Addr) bool {
	return GetIP(addr).To4() != nil
}