move ResolveUnspecifiedAddress(es) here from libp2p/go-addr-util

net/ip.go

@@ -95,6 +95,18 @@ func IsIPUnspecified(m ma.Multiaddr) bool {
 	return net.IP(c.RawValue()).IsUnspecified()
 }
 
+// AddrOverNonLocalIP returns whether the addr uses a non-local ip link
+func AddrOverNonLocalIP(a ma.Multiaddr) bool {
+	split := ma.Split(a)
+	if len(split) < 1 {
+		return false
+	}
+	if IsIP6LinkLocal(split[0]) {
+		return false
+	}
+	return true
+}
+
 // If m matches [zone,ip6,...], return [ip6,...]
 // else if m matches [], [zone], or [zone,...], return nil
 // else return m

net/resolve.go

@@ -0,0 +1,83 @@
+package manet
+
+import (
+	"fmt"
+
+	ma "github.com/multiformats/go-multiaddr"
+)
+
+// ResolveUnspecifiedAddress expands an unspecified ip addresses (/ip4/0.0.0.0, /ip6/::) to
+// use the known local interfaces. If ifaceAddr is nil, we request interface addresses
+// from the network stack. (this is so you can provide a cached value if resolving many addrs)
+func ResolveUnspecifiedAddress(resolve ma.Multiaddr, ifaceAddrs []ma.Multiaddr) ([]ma.Multiaddr, error) {
+	// split address into its components
+	split := ma.Split(resolve)
+
+	// if first component (ip) is not unspecified, use it as is.
+	if !IsIPUnspecified(split[0]) {
+		return []ma.Multiaddr{resolve}, nil
+	}
+
+	out := make([]ma.Multiaddr, 0, len(ifaceAddrs))
+	for _, ia := range ifaceAddrs {
+		// must match the first protocol to be resolve.
+		if ia.Protocols()[0].Code != resolve.Protocols()[0].Code {
+			continue
+		}
+
+		split[0] = ia
+		joined := ma.Join(split...)
+		out = append(out, joined)
+	}
+	if len(out) < 1 {
+		return nil, fmt.Errorf("failed to resolve: %s", resolve)
+	}
+	return out, nil
+}
+
+// ResolveUnspecifiedAddresses expands unspecified ip addresses (/ip4/0.0.0.0, /ip6/::) to
+// use the known local interfaces.
+func ResolveUnspecifiedAddresses(unspecAddrs, ifaceAddrs []ma.Multiaddr) ([]ma.Multiaddr, error) {
+	// todo optimize: only fetch these if we have a "any" addr.
+	if len(ifaceAddrs) < 1 {
+		var err error
+		ifaceAddrs, err = InterfaceAddresses()
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	var outputAddrs []ma.Multiaddr
+	for _, a := range unspecAddrs {
+		// unspecified?
+		resolved, err := ResolveUnspecifiedAddress(a, ifaceAddrs)
+		if err != nil {
+			continue // optimistic. if we can't resolve anything, we'll know at the bottom.
+		}
+		outputAddrs = append(outputAddrs, resolved...)
+	}
+
+	if len(outputAddrs) < 1 {
+		return nil, fmt.Errorf("failed to specify addrs: %s", unspecAddrs)
+	}
+	return outputAddrs, nil
+}
+
+// InterfaceAddresses returns a list of addresses associated with local machine
+// Note: we do not return link local addresses. IP loopback is ok, because we
+// may be connecting to other nodes in the same machine.
+func InterfaceAddresses() ([]ma.Multiaddr, error) {
+	maddrs, err := InterfaceMultiaddrs()
+	if err != nil {
+		return nil, err
+	}
+
+	var out []ma.Multiaddr
+	for _, a := range maddrs {
+		if !AddrOverNonLocalIP(a) {
+			continue
+		}
+		out = append(out, a)
+	}
+	return out, nil
+}

net/resolve_test.go

@@ -0,0 +1,75 @@
+package manet
+
+import (
+	"testing"
+
+	ma "github.com/multiformats/go-multiaddr"
+	"github.com/stretchr/testify/require"
+)
+
+func TestResolvingAddrs(t *testing.T) {
+	unspec := []ma.Multiaddr{
+		newMultiaddr(t, "/ip4/0.0.0.0/tcp/1234"),
+		newMultiaddr(t, "/ip4/1.2.3.4/tcp/1234"),
+		newMultiaddr(t, "/ip6/::/tcp/1234"),
+		newMultiaddr(t, "/ip6/::100/tcp/1234"),
+	}
+
+	iface := []ma.Multiaddr{
+		newMultiaddr(t, "/ip4/127.0.0.1"),
+		newMultiaddr(t, "/ip4/10.20.30.40"),
+		newMultiaddr(t, "/ip6/::1"),
+		newMultiaddr(t, "/ip6/::f"),
+	}
+
+	spec := []ma.Multiaddr{
+		newMultiaddr(t, "/ip4/127.0.0.1/tcp/1234"),
+		newMultiaddr(t, "/ip4/10.20.30.40/tcp/1234"),
+		newMultiaddr(t, "/ip4/1.2.3.4/tcp/1234"),
+		newMultiaddr(t, "/ip6/::1/tcp/1234"),
+		newMultiaddr(t, "/ip6/::f/tcp/1234"),
+		newMultiaddr(t, "/ip6/::100/tcp/1234"),
+	}
+
+	actual, err := ResolveUnspecifiedAddresses(unspec, iface)
+	require.NoError(t, err)
+	require.Equal(t, actual, spec)
+
+	ip4u := []ma.Multiaddr{newMultiaddr(t, "/ip4/0.0.0.0")}
+	ip4i := []ma.Multiaddr{newMultiaddr(t, "/ip4/1.2.3.4")}
+
+	ip6u := []ma.Multiaddr{newMultiaddr(t, "/ip6/::")}
+	ip6i := []ma.Multiaddr{newMultiaddr(t, "/ip6/::1")}
+
+	if _, err := ResolveUnspecifiedAddress(ip4u[0], ip6i); err == nil {
+		t.Fatal("should have failed")
+	}
+	if _, err := ResolveUnspecifiedAddress(ip6u[0], ip4i); err == nil {
+		t.Fatal("should have failed")
+	}
+
+	if _, err := ResolveUnspecifiedAddresses(ip6u, ip4i); err == nil {
+		t.Fatal("should have failed")
+	}
+	if _, err := ResolveUnspecifiedAddresses(ip4u, ip6i); err == nil {
+		t.Fatal("should have failed")
+	}
+}
+
+func TestAddrOverNonLocalIP(t *testing.T) {
+	bad := []ma.Multiaddr{
+		newMultiaddr(t, "/ip6/fe80::1/tcp/1234"),   // link local
+		newMultiaddr(t, "/ip6/fe80::100/tcp/1234"), // link local
+	}
+	good := []ma.Multiaddr{
+		newMultiaddr(t, "/ip4/127.0.0.1/tcp/1234"),
+		newMultiaddr(t, "/ip6/::1/tcp/1234"),
+		newMultiaddr(t, "/ip4/1.2.3.4/udp/1234/utp"),
+	}
+	for _, addr := range bad {
+		require.Falsef(t, AddrOverNonLocalIP(addr), "%s is a link local addr", addr)
+	}
+	for _, addr := range good {
+		require.Truef(t, AddrOverNonLocalIP(addr), "%s is not a link local addr", addr)
+	}
+}