94 lines
2.1 KiB
Go
94 lines
2.1 KiB
Go
// Copyright 2012 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package nettest
|
|
|
|
import "net"
|
|
|
|
// IsMulticastCapable reports whether ifi is an IP multicast-capable
|
|
// network interface. Network must be "ip", "ip4" or "ip6".
|
|
func IsMulticastCapable(network string, ifi *net.Interface) (net.IP, bool) {
|
|
switch network {
|
|
case "ip", "ip4", "ip6":
|
|
default:
|
|
return nil, false
|
|
}
|
|
if ifi == nil || ifi.Flags&net.FlagUp == 0 || ifi.Flags&net.FlagMulticast == 0 {
|
|
return nil, false
|
|
}
|
|
return hasRoutableIP(network, ifi)
|
|
}
|
|
|
|
// RoutedInterface returns a network interface that can route IP
|
|
// traffic and satisfies flags. It returns nil when an appropriate
|
|
// network interface is not found. Network must be "ip", "ip4" or
|
|
// "ip6".
|
|
func RoutedInterface(network string, flags net.Flags) *net.Interface {
|
|
switch network {
|
|
case "ip", "ip4", "ip6":
|
|
default:
|
|
return nil
|
|
}
|
|
ift, err := net.Interfaces()
|
|
if err != nil {
|
|
return nil
|
|
}
|
|
for _, ifi := range ift {
|
|
if ifi.Flags&flags != flags {
|
|
continue
|
|
}
|
|
if _, ok := hasRoutableIP(network, &ifi); !ok {
|
|
continue
|
|
}
|
|
return &ifi
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func hasRoutableIP(network string, ifi *net.Interface) (net.IP, bool) {
|
|
ifat, err := ifi.Addrs()
|
|
if err != nil {
|
|
return nil, false
|
|
}
|
|
for _, ifa := range ifat {
|
|
switch ifa := ifa.(type) {
|
|
case *net.IPAddr:
|
|
if ip := routableIP(network, ifa.IP); ip != nil {
|
|
return ip, true
|
|
}
|
|
case *net.IPNet:
|
|
if ip := routableIP(network, ifa.IP); ip != nil {
|
|
return ip, true
|
|
}
|
|
}
|
|
}
|
|
return nil, false
|
|
}
|
|
|
|
func routableIP(network string, ip net.IP) net.IP {
|
|
if !ip.IsLoopback() && !ip.IsLinkLocalUnicast() && !ip.IsGlobalUnicast() {
|
|
return nil
|
|
}
|
|
switch network {
|
|
case "ip4":
|
|
if ip := ip.To4(); ip != nil {
|
|
return ip
|
|
}
|
|
case "ip6":
|
|
if ip.IsLoopback() { // addressing scope of the loopback address depends on each implementation
|
|
return nil
|
|
}
|
|
if ip := ip.To16(); ip != nil && ip.To4() == nil {
|
|
return ip
|
|
}
|
|
default:
|
|
if ip := ip.To4(); ip != nil {
|
|
return ip
|
|
}
|
|
if ip := ip.To16(); ip != nil {
|
|
return ip
|
|
}
|
|
}
|
|
return nil
|
|
}
|