Merge go-multiaddr-net

Author: Stebalien

net/convert.go

@@ -0,0 +1,330 @@
+package manet
+
+import (
+	"fmt"
+	"net"
+	"path/filepath"
+	"runtime"
+	"strings"
+
+	ma "github.com/multiformats/go-multiaddr"
+)
+
+var errIncorrectNetAddr = fmt.Errorf("incorrect network addr conversion")
+var errNotIP = fmt.Errorf("multiaddr does not start with an IP address")
+
+// FromNetAddr converts a net.Addr type to a Multiaddr.
+func FromNetAddr(a net.Addr) (ma.Multiaddr, error) {
+	return defaultCodecs.FromNetAddr(a)
+}
+
+// FromNetAddr converts a net.Addr to Multiaddress.
+func (cm *CodecMap) FromNetAddr(a net.Addr) (ma.Multiaddr, error) {
+	if a == nil {
+		return nil, fmt.Errorf("nil multiaddr")
+	}
+	p, err := cm.getAddrParser(a.Network())
+	if err != nil {
+		return nil, err
+	}
+
+	return p(a)
+}
+
+// ToNetAddr converts a Multiaddr to a net.Addr
+// Must be ThinWaist. acceptable protocol stacks are:
+// /ip{4,6}/{tcp, udp}
+func ToNetAddr(maddr ma.Multiaddr) (net.Addr, error) {
+	return defaultCodecs.ToNetAddr(maddr)
+}
+
+// ToNetAddr converts a Multiaddress to a standard net.Addr.
+func (cm *CodecMap) ToNetAddr(maddr ma.Multiaddr) (net.Addr, error) {
+	protos := maddr.Protocols()
+	final := protos[len(protos)-1]
+
+	p, err := cm.getMaddrParser(final.Name)
+	if err != nil {
+		return nil, err
+	}
+
+	return p(maddr)
+}
+
+func parseBasicNetMaddr(maddr ma.Multiaddr) (net.Addr, error) {
+	network, host, err := DialArgs(maddr)
+	if err != nil {
+		return nil, err
+	}
+
+	switch network {
+	case "tcp", "tcp4", "tcp6":
+		return net.ResolveTCPAddr(network, host)
+	case "udp", "udp4", "udp6":
+		return net.ResolveUDPAddr(network, host)
+	case "ip", "ip4", "ip6":
+		return net.ResolveIPAddr(network, host)
+	case "unix":
+		return net.ResolveUnixAddr(network, host)
+	}
+
+	return nil, fmt.Errorf("network not supported: %s", network)
+}
+
+func FromIPAndZone(ip net.IP, zone string) (ma.Multiaddr, error) {
+	switch {
+	case ip.To4() != nil:
+		return ma.NewComponent("ip4", ip.String())
+	case ip.To16() != nil:
+		ip6, err := ma.NewComponent("ip6", ip.String())
+		if err != nil {
+			return nil, err
+		}
+		if zone == "" {
+			return ip6, nil
+		} else {
+			zone, err := ma.NewComponent("ip6zone", zone)
+			if err != nil {
+				return nil, err
+			}
+			return zone.Encapsulate(ip6), nil
+		}
+	default:
+		return nil, errIncorrectNetAddr
+	}
+}
+
+// FromIP converts a net.IP type to a Multiaddr.
+func FromIP(ip net.IP) (ma.Multiaddr, error) {
+	return FromIPAndZone(ip, "")
+}
+
+// ToIP converts a Multiaddr to a net.IP when possible
+func ToIP(addr ma.Multiaddr) (net.IP, error) {
+	var ip net.IP
+	ma.ForEach(addr, func(c ma.Component) bool {
+		switch c.Protocol().Code {
+		case ma.P_IP6ZONE:
+			// we can't return these anyways.
+			return true
+		case ma.P_IP6, ma.P_IP4:
+			ip = net.IP(c.RawValue())
+			return false
+		}
+		return false
+	})
+	if ip == nil {
+		return nil, errNotIP
+	}
+	return ip, nil
+}
+
+// DialArgs is a convenience function that returns network and address as
+// expected by net.Dial. See https://godoc.org/net#Dial for an overview of
+// possible return values (we do not support the unixpacket ones yet). Unix
+// addresses do not, at present, compose.
+func DialArgs(m ma.Multiaddr) (string, string, error) {
+	zone, network, ip, port, hostname, err := dialArgComponents(m)
+	if err != nil {
+		return "", "", err
+	}
+
+	// If we have a hostname (dns*), we don't want any fancy ipv6 formatting
+	// logic (zone, brackets, etc.).
+	if hostname {
+		switch network {
+		case "ip", "ip4", "ip6":
+			return network, ip, nil
+		case "tcp", "tcp4", "tcp6", "udp", "udp4", "udp6":
+			return network, ip + ":" + port, nil
+		}
+		// Hostname is only true when network is one of the above.
+		panic("unreachable")
+	}
+
+	switch network {
+	case "ip6":
+		if zone != "" {
+			ip += "%" + zone
+		}
+		fallthrough
+	case "ip4":
+		return network, ip, nil
+	case "tcp4", "udp4":
+		return network, ip + ":" + port, nil
+	case "tcp6", "udp6":
+		if zone != "" {
+			ip += "%" + zone
+		}
+		return network, "[" + ip + "]" + ":" + port, nil
+	case "unix":
+		if runtime.GOOS == "windows" {
+			// convert /c:/... to c:\...
+			ip = filepath.FromSlash(strings.TrimLeft(ip, "/"))
+		}
+		return network, ip, nil
+	default:
+		return "", "", fmt.Errorf("%s is not a 'thin waist' address", m)
+	}
+}
+
+// dialArgComponents extracts the raw pieces used in dialing a Multiaddr
+func dialArgComponents(m ma.Multiaddr) (zone, network, ip, port string, hostname bool, err error) {
+	ma.ForEach(m, func(c ma.Component) bool {
+		switch network {
+		case "":
+			switch c.Protocol().Code {
+			case ma.P_IP6ZONE:
+				if zone != "" {
+					err = fmt.Errorf("%s has multiple zones", m)
+					return false
+				}
+				zone = c.Value()
+				return true
+			case ma.P_IP6:
+				network = "ip6"
+				ip = c.Value()
+				return true
+			case ma.P_IP4:
+				if zone != "" {
+					err = fmt.Errorf("%s has ip4 with zone", m)
+					return false
+				}
+				network = "ip4"
+				ip = c.Value()
+				return true
+			case ma.P_DNS:
+				network = "ip"
+				hostname = true
+				ip = c.Value()
+				return true
+			case ma.P_DNS4:
+				network = "ip4"
+				hostname = true
+				ip = c.Value()
+				return true
+			case ma.P_DNS6:
+				network = "ip6"
+				hostname = true
+				ip = c.Value()
+				return true
+			case ma.P_UNIX:
+				network = "unix"
+				ip = c.Value()
+				return false
+			}
+		case "ip":
+			switch c.Protocol().Code {
+			case ma.P_UDP:
+				network = "udp"
+			case ma.P_TCP:
+				network = "tcp"
+			default:
+				return false
+			}
+			port = c.Value()
+		case "ip4":
+			switch c.Protocol().Code {
+			case ma.P_UDP:
+				network = "udp4"
+			case ma.P_TCP:
+				network = "tcp4"
+			default:
+				return false
+			}
+			port = c.Value()
+		case "ip6":
+			switch c.Protocol().Code {
+			case ma.P_UDP:
+				network = "udp6"
+			case ma.P_TCP:
+				network = "tcp6"
+			default:
+				return false
+			}
+			port = c.Value()
+		}
+		// Done.
+		return false
+	})
+	return
+}
+
+func parseTCPNetAddr(a net.Addr) (ma.Multiaddr, error) {
+	ac, ok := a.(*net.TCPAddr)
+	if !ok {
+		return nil, errIncorrectNetAddr
+	}
+
+	// Get IP Addr
+	ipm, err := FromIPAndZone(ac.IP, ac.Zone)
+	if err != nil {
+		return nil, errIncorrectNetAddr
+	}
+
+	// Get TCP Addr
+	tcpm, err := ma.NewMultiaddr(fmt.Sprintf("/tcp/%d", ac.Port))
+	if err != nil {
+		return nil, errIncorrectNetAddr
+	}
+
+	// Encapsulate
+	return ipm.Encapsulate(tcpm), nil
+}
+
+func parseUDPNetAddr(a net.Addr) (ma.Multiaddr, error) {
+	ac, ok := a.(*net.UDPAddr)
+	if !ok {
+		return nil, errIncorrectNetAddr
+	}
+
+	// Get IP Addr
+	ipm, err := FromIPAndZone(ac.IP, ac.Zone)
+	if err != nil {
+		return nil, errIncorrectNetAddr
+	}
+
+	// Get UDP Addr
+	udpm, err := ma.NewMultiaddr(fmt.Sprintf("/udp/%d", ac.Port))
+	if err != nil {
+		return nil, errIncorrectNetAddr
+	}
+
+	// Encapsulate
+	return ipm.Encapsulate(udpm), nil
+}
+
+func parseIPNetAddr(a net.Addr) (ma.Multiaddr, error) {
+	ac, ok := a.(*net.IPAddr)
+	if !ok {
+		return nil, errIncorrectNetAddr
+	}
+	return FromIPAndZone(ac.IP, ac.Zone)
+}
+
+func parseIPPlusNetAddr(a net.Addr) (ma.Multiaddr, error) {
+	ac, ok := a.(*net.IPNet)
+	if !ok {
+		return nil, errIncorrectNetAddr
+	}
+	return FromIP(ac.IP)
+}
+
+func parseUnixNetAddr(a net.Addr) (ma.Multiaddr, error) {
+	ac, ok := a.(*net.UnixAddr)
+	if !ok {
+		return nil, errIncorrectNetAddr
+	}
+
+	path := ac.Name
+	if runtime.GOOS == "windows" {
+		// Convert c:\foobar\... to c:/foobar/...
+		path = filepath.ToSlash(path)
+	}
+	if len(path) == 0 || path[0] != '/' {
+		// convert "" and "c:/..." to "/..."
+		path = "/" + path
+	}
+
+	return ma.NewComponent("unix", path)
+}