net.Addr -> Multiaddr

net.go

+package multiaddr
+
+import (
+	"fmt"
+	"net"
+)
+
+var errIncorrectNetAddr = fmt.Errorf("incorrect network addr conversion")
+
+// FromNetAddr converts a net.Addr type to a Multiaddr.
+func FromNetAddr(a net.Addr) (*Multiaddr, error) {
+	switch a.Network() {
+	case "tcp", "tcp4", "tcp6":
+		ac, ok := a.(*net.TCPAddr)
+		if !ok {
+			return nil, errIncorrectNetAddr
+		}
+
+		// Get IP Addr
+		ipm, err := FromIP(ac.IP)
+		if err != nil {
+			return nil, errIncorrectNetAddr
+		}
+
+		// Get TCP Addr
+		tcpm, err := NewMultiaddr(fmt.Sprintf("/tcp/%d", ac.Port))
+		if err != nil {
+			return nil, errIncorrectNetAddr
+		}
+
+		// Encapsulate
+		return ipm.Encapsulate(tcpm), nil
+
+	case "udp", "upd4", "udp6":
+		ac, ok := a.(*net.UDPAddr)
+		if !ok {
+			return nil, errIncorrectNetAddr
+		}
+
+		// Get IP Addr
+		ipm, err := FromIP(ac.IP)
+		if err != nil {
+			return nil, errIncorrectNetAddr
+		}
+
+		// Get UDP Addr
+		udpm, err := NewMultiaddr(fmt.Sprintf("/udp/%d", ac.Port))
+		if err != nil {
+			return nil, errIncorrectNetAddr
+		}
+
+		// Encapsulate
+		return ipm.Encapsulate(udpm), nil
+
+	case "ip", "ip4", "ip6":
+		ac, ok := a.(*net.IPAddr)
+		if !ok {
+			return nil, errIncorrectNetAddr
+		}
+		return FromIP(ac.IP)
+
+	default:
+		return nil, fmt.Errorf("unknown network %v", a.Network())
+	}
+}
+
+// FromIP converts a net.IP type to a Multiaddr.
+func FromIP(ip net.IP) (*Multiaddr, error) {
+	switch {
+	case ip.To4() != nil:
+		return NewMultiaddr("/ip4/" + ip.String())
+	case ip.To16() != nil:
+		return NewMultiaddr("/ip6/" + ip.String())
+	default:
+		return nil, errIncorrectNetAddr
+	}
+}

net_test.go

+package multiaddr
+
+import (
+	"net"
+	"testing"
+)
+
+type GenFunc func() (*Multiaddr, error)
+
+func testConvert(t *testing.T, s string, gen GenFunc) {
+	m, err := gen()
+	if err != nil {
+		t.Fatal("failed to generate.")
+	}
+
+	if s2, _ := m.String(); err != nil || s2 != s {
+		t.Fatal("failed to convert: " + s + " != " + s2)
+	}
+}
+
+func TestFromIP4(t *testing.T) {
+	testConvert(t, "/ip4/10.20.30.40", func() (*Multiaddr, error) {
+		return FromIP(net.ParseIP("10.20.30.40"))
+	})
+}
+
+func TestFromIP6(t *testing.T) {
+	testConvert(t, "/ip6/2001:4860:0:2001::68", func() (*Multiaddr, error) {
+		return FromIP(net.ParseIP("2001:4860:0:2001::68"))
+	})
+}
+
+func TestFromTCP(t *testing.T) {
+	testConvert(t, "/ip4/10.20.30.40/tcp/1234", func() (*Multiaddr, error) {
+		return FromNetAddr(&net.TCPAddr{
+			IP:   net.ParseIP("10.20.30.40"),
+			Port: 1234,
+		})
+	})
+}
+
+func TestFromUDP(t *testing.T) {
+	testConvert(t, "/ip4/10.20.30.40/udp/1234", func() (*Multiaddr, error) {
+		return FromNetAddr(&net.UDPAddr{
+			IP:   net.ParseIP("10.20.30.40"),
+			Port: 1234,
+		})
+	})
+}