commit 846473b3549c264245354a3117d87b96a945f287 Author: Arlo Breault arlolra@gmail.com Date: Fri Feb 7 15:39:44 2020 -0500

Unmarshal the SDP to filter attributes

Instead of string manipulation. --- client/lib/lib_test.go | 18 +++++++------- client/lib/rendezvous.go | 64 ++++++++++++++++++++++++++++-------------------- 2 files changed, 46 insertions(+), 36 deletions(-)

diff --git a/client/lib/lib_test.go b/client/lib/lib_test.go index adfc9ec..b413508 100644 --- a/client/lib/lib_test.go +++ b/client/lib/lib_test.go @@ -358,17 +358,17 @@ func TestSnowflakeClient(t *testing.T) { })

Convey("Strip", t, func() { - const offerStart = `{"type":"offer","sdp":"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"}` + 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 + "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) diff --git a/client/lib/rendezvous.go b/client/lib/rendezvous.go index bd8ff00..190df66 100644 --- a/client/lib/rendezvous.go +++ b/client/lib/rendezvous.go @@ -17,7 +17,6 @@ import ( "net" "net/http" "net/url" - "regexp"

"github.com/pion/sdp" "github.com/pion/webrtc" @@ -95,25 +94,40 @@ func IsLocal(ip net.IP) bool {

// Removes local LAN address ICE candidates func stripLocalAddresses(str string) string { - re := regexp.MustCompile(`a=candidate:.*?\r\n`) - return re.ReplaceAllStringFunc(str, func(s string) string { - t := s[len("a=candidate:") : len(s)-len("\r\n")] - var ice sdp.ICECandidate - err := ice.Unmarshal(t) - if err != nil { - return s - } - if ice.Typ == "host" { - ip := net.ParseIP(ice.Address) - if ip == nil { - return s - } - if IsLocal(ip) || ip.IsUnspecified() || ip.IsLoopback() { - return "" + 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 { + attrs = append(attrs, a) + continue + } + if ice.Typ == "host" { + ip := net.ParseIP(ice.Address) + if ip == nil { + attrs = append(attrs, a) + continue + } + if IsLocal(ip) || ip.IsUnspecified() || ip.IsLoopback() { + continue + } + } } + attrs = append(attrs, a) } - return s - }) + m.Attributes = attrs + } + bts, err := desc.Marshal() + if err != nil { + return str + } + return string(bts) }

// Roundtrip HTTP POST using WebRTC SessionDescriptions. @@ -124,20 +138,16 @@ func (bc *BrokerChannel) Negotiate(offer *webrtc.SessionDescription) ( *webrtc.SessionDescription, error) { log.Println("Negotiating via BrokerChannel...\nTarget URL: ", bc.Host, "\nFront URL: ", bc.url.Host) - str := serializeSessionDescription(offer) // Ideally, we could specify an `RTCIceTransportPolicy` that would handle // this for us. However, "public" was removed from the draft spec. // See https://developer.mozilla.org/en-US/docs/Web/API/RTCConfiguration#RTCIceTran... - // - // FIXME: We are stripping local addresses from the JSON serialized string, - // which is expedient but unsatisfying. We could advocate upstream to - // implement a non-standard ICE transport policy, or to somehow alter - // APIs to avoid adding the undesirable candidates or a method to filter - // them from the marshalled session description. if !bc.keepLocalAddresses { - str = stripLocalAddresses(str) + offer = &webrtc.SessionDescription{ + Type: offer.Type, + SDP: stripLocalAddresses(offer.SDP), + } } - data := bytes.NewReader([]byte(str)) + data := bytes.NewReader([]byte(serializeSessionDescription(offer))) // Suffix with broker's client registration handler. clientURL := bc.url.ResolveReference(&url.URL{Path: "client"}) request, err := http.NewRequest("POST", clientURL.String(), data)