Move StripLocalAddresses to a common util

Trac: 19026

client/lib/lib_test.go

@@ -358,21 +358,4 @@ func TestSnowflakeClient(t *testing.T) {
 		})
 	})
 
-	Convey("Strip", t, func() {
-		const offerStart = "v=0\r\no=- 4358805017720277108 2 IN IP4 8.8.8.8\r\ns=-\r\nt=0 0\r\na=group:BUNDLE data\r\na=msid-semantic: WMS\r\nm=application 56688 DTLS/SCTP 5000\r\nc=IN IP4 8.8.8.8\r\n"
-		const goodCandidate = "a=candidate:3769337065 1 udp 2122260223 8.8.8.8 56688 typ host generation 0 network-id 1 network-cost 50\r\n"
-		const offerEnd = "a=ice-ufrag:aMAZ\r\na=ice-pwd:jcHb08Jjgrazp2dzjdrvPPvV\r\na=ice-options:trickle\r\na=fingerprint:sha-256 C8:88:EE:B9:E7:02:2E:21:37:ED:7A:D1:EB:2B:A3:15:A2:3B:5B:1C:3D:D4:D5:1F:06:CF:52:40:03:F8:DD:66\r\na=setup:actpass\r\na=mid:data\r\na=sctpmap:5000 webrtc-datachannel 1024\r\n"
-
-		offer := offerStart + goodCandidate +
-			"a=candidate:3769337065 1 udp 2122260223 192.168.0.100 56688 typ host generation 0 network-id 1 network-cost 50\r\n" + // IsLocal IPv4
-			"a=candidate:3769337065 1 udp 2122260223 fdf8:f53b:82e4::53 56688 typ host generation 0 network-id 1 network-cost 50\r\n" + // IsLocal IPv6
-			"a=candidate:3769337065 1 udp 2122260223 0.0.0.0 56688 typ host generation 0 network-id 1 network-cost 50\r\n" + // IsUnspecified IPv4
-			"a=candidate:3769337065 1 udp 2122260223 :: 56688 typ host generation 0 network-id 1 network-cost 50\r\n" + // IsUnspecified IPv6
-			"a=candidate:3769337065 1 udp 2122260223 127.0.0.1 56688 typ host generation 0 network-id 1 network-cost 50\r\n" + // IsLoopback IPv4
-			"a=candidate:3769337065 1 udp 2122260223 ::1 56688 typ host generation 0 network-id 1 network-cost 50\r\n" + // IsLoopback IPv6
-			offerEnd
-
-		So(stripLocalAddresses(offer), ShouldEqual, offerStart+goodCandidate+offerEnd)
-	})
-
 }

client/lib/rendezvous.go

@@ -14,12 +14,10 @@ import (
 	"io"
 	"io/ioutil"
 	"log"
-	"net"
 	"net/http"
 	"net/url"
 
 	"git.torproject.org/pluggable-transports/snowflake.git/common/util"
-	"github.com/pion/sdp/v2"
 	"github.com/pion/webrtc/v2"
 )
 
@@ -81,49 +79,6 @@ func limitedRead(r io.Reader, limit int64) ([]byte, error) {
 	return p, err
 }
 
-// Stolen from https://github.com/golang/go/pull/30278
-func IsLocal(ip net.IP) bool {
-	if ip4 := ip.To4(); ip4 != nil {
-		// Local IPv4 addresses are defined in https://tools.ietf.org/html/rfc1918
-		return ip4[0] == 10 ||
-			(ip4[0] == 172 && ip4[1]&0xf0 == 16) ||
-			(ip4[0] == 192 && ip4[1] == 168)
-	}
-	// Local IPv6 addresses are defined in https://tools.ietf.org/html/rfc4193
-	return len(ip) == net.IPv6len && ip[0]&0xfe == 0xfc
-}
-
-// Removes local LAN address ICE candidates
-func stripLocalAddresses(str string) string {
-	var desc sdp.SessionDescription
-	err := desc.Unmarshal([]byte(str))
-	if err != nil {
-		return str
-	}
-	for _, m := range desc.MediaDescriptions {
-		attrs := make([]sdp.Attribute, 0)
-		for _, a := range m.Attributes {
-			if a.IsICECandidate() {
-				ice, err := a.ToICECandidate()
-				if err == nil && ice.Typ == "host" {
-					ip := net.ParseIP(ice.Address)
-					if ip != nil && (IsLocal(ip) || ip.IsUnspecified() || ip.IsLoopback()) {
-						/* no append in this case */
-						continue
-					}
-				}
-			}
-			attrs = append(attrs, a)
-		}
-		m.Attributes = attrs
-	}
-	bts, err := desc.Marshal()
-	if err != nil {
-		return str
-	}
-	return string(bts)
-}
-
 // Roundtrip HTTP POST using WebRTC SessionDescriptions.
 //
 // Send an SDP offer to the broker, which assigns a proxy and responds
@@ -138,7 +93,7 @@ func (bc *BrokerChannel) Negotiate(offer *webrtc.SessionDescription) (
 	if !bc.keepLocalAddresses {
 		offer = &webrtc.SessionDescription{
 			Type: offer.Type,
-			SDP:  stripLocalAddresses(offer.SDP),
+			SDP:  util.StripLocalAddresses(offer.SDP),
 		}
 	}
 	data := bytes.NewReader([]byte(util.SerializeSessionDescription(offer)))

common/util/util.go

@@ -3,7 +3,9 @@ package util
 import (
 	"encoding/json"
 	"log"
+	"net"
 
+	"github.com/pion/sdp/v2"
 	"github.com/pion/webrtc/v2"
 )
 
@@ -56,3 +58,46 @@ func DeserializeSessionDescription(msg string) *webrtc.SessionDescription {
 		SDP:  parsed["sdp"].(string),
 	}
 }
+
+// Stolen from https://github.com/golang/go/pull/30278
+func IsLocal(ip net.IP) bool {
+	if ip4 := ip.To4(); ip4 != nil {
+		// Local IPv4 addresses are defined in https://tools.ietf.org/html/rfc1918
+		return ip4[0] == 10 ||
+			(ip4[0] == 172 && ip4[1]&0xf0 == 16) ||
+			(ip4[0] == 192 && ip4[1] == 168)
+	}
+	// Local IPv6 addresses are defined in https://tools.ietf.org/html/rfc4193
+	return len(ip) == net.IPv6len && ip[0]&0xfe == 0xfc
+}
+
+// Removes local LAN address ICE candidates
+func StripLocalAddresses(str string) string {
+	var desc sdp.SessionDescription
+	err := desc.Unmarshal([]byte(str))
+	if err != nil {
+		return str
+	}
+	for _, m := range desc.MediaDescriptions {
+		attrs := make([]sdp.Attribute, 0)
+		for _, a := range m.Attributes {
+			if a.IsICECandidate() {
+				ice, err := a.ToICECandidate()
+				if err == nil && ice.Typ == "host" {
+					ip := net.ParseIP(ice.Address)
+					if ip != nil && (IsLocal(ip) || ip.IsUnspecified() || ip.IsLoopback()) {
+						/* no append in this case */
+						continue
+					}
+				}
+			}
+			attrs = append(attrs, a)
+		}
+		m.Attributes = attrs
+	}
+	bts, err := desc.Marshal()
+	if err != nil {
+		return str
+	}
+	return string(bts)
+}

common/util/util_test.go

@@ -0,0 +1,26 @@
+package util
+
+import (
+	"testing"
+
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func TestUtil(t *testing.T) {
+	Convey("Strip", t, func() {
+		const offerStart = "v=0\r\no=- 4358805017720277108 2 IN IP4 8.8.8.8\r\ns=-\r\nt=0 0\r\na=group:BUNDLE data\r\na=msid-semantic: WMS\r\nm=application 56688 DTLS/SCTP 5000\r\nc=IN IP4 8.8.8.8\r\n"
+		const goodCandidate = "a=candidate:3769337065 1 udp 2122260223 8.8.8.8 56688 typ host generation 0 network-id 1 network-cost 50\r\n"
+		const offerEnd = "a=ice-ufrag:aMAZ\r\na=ice-pwd:jcHb08Jjgrazp2dzjdrvPPvV\r\na=ice-options:trickle\r\na=fingerprint:sha-256 C8:88:EE:B9:E7:02:2E:21:37:ED:7A:D1:EB:2B:A3:15:A2:3B:5B:1C:3D:D4:D5:1F:06:CF:52:40:03:F8:DD:66\r\na=setup:actpass\r\na=mid:data\r\na=sctpmap:5000 webrtc-datachannel 1024\r\n"
+
+		offer := offerStart + goodCandidate +
+			"a=candidate:3769337065 1 udp 2122260223 192.168.0.100 56688 typ host generation 0 network-id 1 network-cost 50\r\n" + // IsLocal IPv4
+			"a=candidate:3769337065 1 udp 2122260223 fdf8:f53b:82e4::53 56688 typ host generation 0 network-id 1 network-cost 50\r\n" + // IsLocal IPv6
+			"a=candidate:3769337065 1 udp 2122260223 0.0.0.0 56688 typ host generation 0 network-id 1 network-cost 50\r\n" + // IsUnspecified IPv4
+			"a=candidate:3769337065 1 udp 2122260223 :: 56688 typ host generation 0 network-id 1 network-cost 50\r\n" + // IsUnspecified IPv6
+			"a=candidate:3769337065 1 udp 2122260223 127.0.0.1 56688 typ host generation 0 network-id 1 network-cost 50\r\n" + // IsLoopback IPv4
+			"a=candidate:3769337065 1 udp 2122260223 ::1 56688 typ host generation 0 network-id 1 network-cost 50\r\n" + // IsLoopback IPv6
+			offerEnd
+
+		So(StripLocalAddresses(offer), ShouldEqual, offerStart+goodCandidate+offerEnd)
+	})
+}