Golang go-multiaddr.Multiaddr類代碼示例

// AddrMatch returns the Multiaddrs that match the protocol stack on addr
func AddrMatch(match ma.Multiaddr, addrs []ma.Multiaddr) []ma.Multiaddr {

	// we should match transports entirely.
	p1s := match.Protocols()

	out := make([]ma.Multiaddr, 0, len(addrs))
	for _, a := range addrs {
		p2s := a.Protocols()
		if len(p1s) != len(p2s) {
			continue
		}

		match := true
		for i, p2 := range p2s {
			if p1s[i].Code != p2.Code {
				match = false
				break
			}
		}
		if match {
			out = append(out, a)
		}
	}
	return out
}

// DialArgs is a convenience function returning arguments for use in net.Dial
func DialArgs(m ma.Multiaddr) (string, string, error) {
	if !IsThinWaist(m) {
		return "", "", fmt.Errorf("%s is not a 'thin waist' address", m)
	}

	str := m.String()
	parts := strings.Split(str, "/")[1:]

	if len(parts) == 2 { // only IP
		return parts[0], parts[1], nil
	}

	network := parts[2]
	if parts[2] == "udp" && len(parts) > 4 && parts[4] == "utp" {
		network = parts[4]
	}

	var host string
	switch parts[0] {
	case "ip4":
		network = network + "4"
		host = strings.Join([]string{parts[1], parts[3]}, ":")
	case "ip6":
		network = network + "6"
		host = fmt.Sprintf("[%s]:%s", parts[1], parts[3])
	}
	return network, host, nil
}

// 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
}

// Dial metadata is metadata for dial events
func Dial(sys string, lid, rid peer.ID, laddr, raddr ma.Multiaddr) DeferredMap {
	m := DeferredMap{}
	m["subsystem"] = sys
	if lid != "" {
		m["localPeer"] = func() interface{} { return lid.Pretty() }
	}
	if laddr != nil {
		m["localAddr"] = func() interface{} { return laddr.String() }
	}
	if rid != "" {
		m["remotePeer"] = func() interface{} { return rid.Pretty() }
	}
	if raddr != nil {
		m["remoteAddr"] = func() interface{} { return raddr.String() }
	}
	return m
}

func outfmt(m ma.Multiaddr) string {
	switch format {
	case "string":
		return m.String()
	case "slice":
		return fmt.Sprintf("%v", m.Bytes())
	case "bytes":
		return string(m.Bytes())
	case "hex":
		return "0x" + hex.EncodeToString(m.Bytes())
	}

	die("error: invalid format", format)
	return ""
}

// IsThinWaist returns whether a Multiaddr starts with "Thin Waist" Protocols.
// This means: /{IP4, IP6}[/{TCP, UDP}]
func IsThinWaist(m ma.Multiaddr) bool {
	p := m.Protocols()

	// nothing? not even a waist.
	if len(p) == 0 {
		return false
	}

	if p[0].Code != ma.P_IP4 && p[0].Code != ma.P_IP6 {
		return false
	}

	// only IP? still counts.
	if len(p) == 1 {
		return true
	}

	switch p[1].Code {
	case ma.P_TCP, ma.P_UDP, ma.P_IP4, ma.P_IP6:
		return true
	default:
		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})
}