// IsIPLoopback returns whether a Multiaddr is a "Loopback" IP address
// This means either /ip4/127.0.0.1 or /ip6/::1
// TODO: differentiate IsIPLoopback and OverIPLoopback
func IsIPLoopback(m ma.Multiaddr) bool {
b := m.Bytes()
// /ip4/127 prefix (_entire_ /8 is loopback...)
if bytes.HasPrefix(b, []byte{ma.P_IP4, 127}) {
return true
}
// /ip6/::1
if IP6Loopback.Equal(m) || IP6LinkLocalLoopback.Equal(m) {
return true
}
return false
}
// IP6 Link Local addresses are non routable. The prefix is technically
// fe80::/10, but we test fe80::/16 for simplicity (no need to mask).
// So far, no hardware interfaces exist long enough to use those 2 bits.
// Send a PR if there is.
func IsIP6LinkLocal(m ma.Multiaddr) bool {
return bytes.HasPrefix(m.Bytes(), []byte{ma.P_IP6, 0xfe, 0x80})
}