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

Author: marten-seemann

go.mod

@@ -6,4 +6,5 @@ require (
 	github.com/ipfs/go-cid v0.0.7
 	github.com/multiformats/go-multihash v0.0.14
 	github.com/multiformats/go-varint v0.0.6
+	github.com/stretchr/testify v1.7.0
 )

go.sum

@@ -1,3 +1,5 @@
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/ipfs/go-cid v0.0.7 h1:ysQJVJA3fNDF1qigJbsSQOdjhVLsOEoPdh0+R97k3jY=
 github.com/ipfs/go-cid v0.0.7/go.mod h1:6Ux9z5e+HpkQdckYoX1PG/6xqKspzlEIR5SDmgqgC/I=
 github.com/minio/blake2b-simd v0.0.0-20160723061019-3f5f724cb5b1 h1:lYpkrQH5ajf0OXOcUbGjvZxxijuBwbbmlSxLiuofa+g=
@@ -19,8 +21,13 @@ github.com/multiformats/go-multihash v0.0.14/go.mod h1:VdAWLKTwram9oKAatUcLxBNUj
 github.com/multiformats/go-varint v0.0.5/go.mod h1:3Ls8CIEsrijN6+B7PbrXRPxHRPuXSrVKRY101jdMZYE=
 github.com/multiformats/go-varint v0.0.6 h1:gk85QWKxh3TazbLxED/NlDVv8+q+ReFJk7Y2W/KhfNY=
 github.com/multiformats/go-varint v0.0.6/go.mod h1:3Ls8CIEsrijN6+B7PbrXRPxHRPuXSrVKRY101jdMZYE=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/spaolacci/murmur3 v1.1.0 h1:7c1g84S4BPRrfL5Xrdp6fOJ206sU9y293DDHaoy0bLI=
 github.com/spaolacci/murmur3 v1.1.0/go.mod h1:JwIasOWyU6f++ZhiEuf87xNszmSA2myDM2Kzu9HwQUA=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20190611184440-5c40567a22f8 h1:1wopBVtVdWnn03fZelqdXTqk7U7zPQCb+T4rbU9ZEoU=
 golang.org/x/crypto v0.0.0-20190611184440-5c40567a22f8/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
@@ -29,3 +36,7 @@ golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5h
 golang.org/x/sys v0.0.0-20190412213103-97732733099d h1:+R4KGOnez64A81RvjARKc4UT5/tI9ujCIVX+P5KiHuI=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

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)
+	}
+}