mirror of
https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake.git
synced 2025-10-14 14:11:23 -04:00
1b29ad7de1
Update our dependency on pion/sdp from v2 to v3, to match pion/webrtc v3. This requires some changes in how we parse out addresses from ice candidates. This will ease tor browser builds of snowflake since we are now only relying on one version of pion/sdp instead of two different ones.
99 lines
2.5 KiB
Go
99 lines
2.5 KiB
Go
package util
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import (
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"encoding/json"
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"errors"
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"net"
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"github.com/pion/ice/v2"
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"github.com/pion/sdp/v3"
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"github.com/pion/webrtc/v3"
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)
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func SerializeSessionDescription(desc *webrtc.SessionDescription) (string, error) {
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bytes, err := json.Marshal(*desc)
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if err != nil {
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return "", err
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}
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return string(bytes), nil
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}
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func DeserializeSessionDescription(msg string) (*webrtc.SessionDescription, error) {
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var parsed map[string]interface{}
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err := json.Unmarshal([]byte(msg), &parsed)
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if err != nil {
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return nil, err
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}
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if _, ok := parsed["type"]; !ok {
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return nil, errors.New("cannot deserialize SessionDescription without type field")
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}
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if _, ok := parsed["sdp"]; !ok {
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return nil, errors.New("cannot deserialize SessionDescription without sdp field")
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}
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var stype webrtc.SDPType
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switch parsed["type"].(string) {
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default:
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return nil, errors.New("Unknown SDP type")
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case "offer":
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stype = webrtc.SDPTypeOffer
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case "pranswer":
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stype = webrtc.SDPTypePranswer
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case "answer":
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stype = webrtc.SDPTypeAnswer
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case "rollback":
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stype = webrtc.SDPTypeRollback
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}
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return &webrtc.SessionDescription{
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Type: stype,
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SDP: parsed["sdp"].(string),
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}, nil
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}
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// Stolen from https://github.com/golang/go/pull/30278
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func IsLocal(ip net.IP) bool {
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if ip4 := ip.To4(); ip4 != nil {
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// Local IPv4 addresses are defined in https://tools.ietf.org/html/rfc1918
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return ip4[0] == 10 ||
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(ip4[0] == 172 && ip4[1]&0xf0 == 16) ||
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(ip4[0] == 192 && ip4[1] == 168) ||
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// Carrier-Grade NAT as per https://tools.ietf.org/htm/rfc6598
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(ip4[0] == 100 && ip4[1]&0xc0 == 64) ||
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// Dynamic Configuration as per https://tools.ietf.org/htm/rfc3927
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(ip4[0] == 169 && ip4[1] == 254)
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}
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// Local IPv6 addresses are defined in https://tools.ietf.org/html/rfc4193
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return len(ip) == net.IPv6len && ip[0]&0xfe == 0xfc
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}
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// Removes local LAN address ICE candidates
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func StripLocalAddresses(str string) string {
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var desc sdp.SessionDescription
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err := desc.Unmarshal([]byte(str))
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if err != nil {
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return str
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}
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for _, m := range desc.MediaDescriptions {
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attrs := make([]sdp.Attribute, 0)
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for _, a := range m.Attributes {
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if a.IsICECandidate() {
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c, err := ice.UnmarshalCandidate(a.Value)
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if err == nil && c.Type() == ice.CandidateTypeHost {
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ip := net.ParseIP(c.Address())
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if ip != nil && (IsLocal(ip) || ip.IsUnspecified() || ip.IsLoopback()) {
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/* no append in this case */
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continue
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}
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}
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}
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attrs = append(attrs, a)
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}
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m.Attributes = attrs
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}
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bts, err := desc.Marshal()
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if err != nil {
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return str
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}
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return string(bts)
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}
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