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server/vendor/github.com/pion/sdp/v3/jsep.go

@@ -0,0 +1,210 @@
+// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
+// SPDX-License-Identifier: MIT
+
+package sdp
+
+import (
+	"fmt"
+	"net/url"
+	"strconv"
+	"time"
+)
+
+// Constants for SDP attributes used in JSEP
+const (
+	AttrKeyCandidate        = "candidate"
+	AttrKeyEndOfCandidates  = "end-of-candidates"
+	AttrKeyIdentity         = "identity"
+	AttrKeyGroup            = "group"
+	AttrKeySSRC             = "ssrc"
+	AttrKeySSRCGroup        = "ssrc-group"
+	AttrKeyMsid             = "msid"
+	AttrKeyMsidSemantic     = "msid-semantic"
+	AttrKeyConnectionSetup  = "setup"
+	AttrKeyMID              = "mid"
+	AttrKeyICELite          = "ice-lite"
+	AttrKeyRTCPMux          = "rtcp-mux"
+	AttrKeyRTCPRsize        = "rtcp-rsize"
+	AttrKeyInactive         = "inactive"
+	AttrKeyRecvOnly         = "recvonly"
+	AttrKeySendOnly         = "sendonly"
+	AttrKeySendRecv         = "sendrecv"
+	AttrKeyExtMap           = "extmap"
+	AttrKeyExtMapAllowMixed = "extmap-allow-mixed"
+)
+
+// Constants for semantic tokens used in JSEP
+const (
+	SemanticTokenLipSynchronization     = "LS"
+	SemanticTokenFlowIdentification     = "FID"
+	SemanticTokenForwardErrorCorrection = "FEC"
+	SemanticTokenWebRTCMediaStreams     = "WMS"
+)
+
+// Constants for extmap key
+const (
+	ExtMapValueTransportCC = 3
+)
+
+func extMapURI() map[int]string {
+	return map[int]string{
+		ExtMapValueTransportCC: "http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01",
+	}
+}
+
+// API to match draft-ietf-rtcweb-jsep
+// Move to webrtc or its own package?
+
+// NewJSEPSessionDescription creates a new SessionDescription with
+// some settings that are required by the JSEP spec.
+//
+// Note: Since v2.4.0, session ID has been fixed to use crypto random according to
+//
+//	JSEP spec, so that NewJSEPSessionDescription now returns error as a second
+//	return value.
+func NewJSEPSessionDescription(identity bool) (*SessionDescription, error) {
+	sid, err := newSessionID()
+	if err != nil {
+		return nil, err
+	}
+	d := &SessionDescription{
+		Version: 0,
+		Origin: Origin{
+			Username:       "-",
+			SessionID:      sid,
+			SessionVersion: uint64(time.Now().Unix()),
+			NetworkType:    "IN",
+			AddressType:    "IP4",
+			UnicastAddress: "0.0.0.0",
+		},
+		SessionName: "-",
+		TimeDescriptions: []TimeDescription{
+			{
+				Timing: Timing{
+					StartTime: 0,
+					StopTime:  0,
+				},
+				RepeatTimes: nil,
+			},
+		},
+		Attributes: []Attribute{
+			// 	"Attribute(ice-options:trickle)", // TODO: implement trickle ICE
+		},
+	}
+
+	if identity {
+		d.WithPropertyAttribute(AttrKeyIdentity)
+	}
+
+	return d, nil
+}
+
+// WithPropertyAttribute adds a property attribute 'a=key' to the session description
+func (s *SessionDescription) WithPropertyAttribute(key string) *SessionDescription {
+	s.Attributes = append(s.Attributes, NewPropertyAttribute(key))
+	return s
+}
+
+// WithValueAttribute adds a value attribute 'a=key:value' to the session description
+func (s *SessionDescription) WithValueAttribute(key, value string) *SessionDescription {
+	s.Attributes = append(s.Attributes, NewAttribute(key, value))
+	return s
+}
+
+// WithFingerprint adds a fingerprint to the session description
+func (s *SessionDescription) WithFingerprint(algorithm, value string) *SessionDescription {
+	return s.WithValueAttribute("fingerprint", algorithm+" "+value)
+}
+
+// WithMedia adds a media description to the session description
+func (s *SessionDescription) WithMedia(md *MediaDescription) *SessionDescription {
+	s.MediaDescriptions = append(s.MediaDescriptions, md)
+	return s
+}
+
+// NewJSEPMediaDescription creates a new MediaName with
+// some settings that are required by the JSEP spec.
+func NewJSEPMediaDescription(codecType string, _ []string) *MediaDescription {
+	return &MediaDescription{
+		MediaName: MediaName{
+			Media:  codecType,
+			Port:   RangedPort{Value: 9},
+			Protos: []string{"UDP", "TLS", "RTP", "SAVPF"},
+		},
+		ConnectionInformation: &ConnectionInformation{
+			NetworkType: "IN",
+			AddressType: "IP4",
+			Address: &Address{
+				Address: "0.0.0.0",
+			},
+		},
+	}
+}
+
+// WithPropertyAttribute adds a property attribute 'a=key' to the media description
+func (d *MediaDescription) WithPropertyAttribute(key string) *MediaDescription {
+	d.Attributes = append(d.Attributes, NewPropertyAttribute(key))
+	return d
+}
+
+// WithValueAttribute adds a value attribute 'a=key:value' to the media description
+func (d *MediaDescription) WithValueAttribute(key, value string) *MediaDescription {
+	d.Attributes = append(d.Attributes, NewAttribute(key, value))
+	return d
+}
+
+// WithFingerprint adds a fingerprint to the media description
+func (d *MediaDescription) WithFingerprint(algorithm, value string) *MediaDescription {
+	return d.WithValueAttribute("fingerprint", algorithm+" "+value)
+}
+
+// WithICECredentials adds ICE credentials to the media description
+func (d *MediaDescription) WithICECredentials(username, password string) *MediaDescription {
+	return d.
+		WithValueAttribute("ice-ufrag", username).
+		WithValueAttribute("ice-pwd", password)
+}
+
+// WithCodec adds codec information to the media description
+func (d *MediaDescription) WithCodec(payloadType uint8, name string, clockrate uint32, channels uint16, fmtp string) *MediaDescription {
+	d.MediaName.Formats = append(d.MediaName.Formats, strconv.Itoa(int(payloadType)))
+	rtpmap := fmt.Sprintf("%d %s/%d", payloadType, name, clockrate)
+	if channels > 0 {
+		rtpmap += fmt.Sprintf("/%d", channels)
+	}
+	d.WithValueAttribute("rtpmap", rtpmap)
+	if fmtp != "" {
+		d.WithValueAttribute("fmtp", fmt.Sprintf("%d %s", payloadType, fmtp))
+	}
+	return d
+}
+
+// WithMediaSource adds media source information to the media description
+func (d *MediaDescription) WithMediaSource(ssrc uint32, cname, streamLabel, label string) *MediaDescription {
+	return d.
+		WithValueAttribute("ssrc", fmt.Sprintf("%d cname:%s", ssrc, cname)). // Deprecated but not phased out?
+		WithValueAttribute("ssrc", fmt.Sprintf("%d msid:%s %s", ssrc, streamLabel, label)).
+		WithValueAttribute("ssrc", fmt.Sprintf("%d mslabel:%s", ssrc, streamLabel)). // Deprecated but not phased out?
+		WithValueAttribute("ssrc", fmt.Sprintf("%d label:%s", ssrc, label))          // Deprecated but not phased out?
+}
+
+// WithCandidate adds an ICE candidate to the media description
+// Deprecated: use WithICECandidate instead
+func (d *MediaDescription) WithCandidate(value string) *MediaDescription {
+	return d.WithValueAttribute("candidate", value)
+}
+
+// WithExtMap adds an extmap to the media description
+func (d *MediaDescription) WithExtMap(e ExtMap) *MediaDescription {
+	return d.WithPropertyAttribute(e.Marshal())
+}
+
+// WithTransportCCExtMap adds an extmap to the media description
+func (d *MediaDescription) WithTransportCCExtMap() *MediaDescription {
+	uri, _ := url.Parse(extMapURI()[ExtMapValueTransportCC])
+	e := ExtMap{
+		Value: ExtMapValueTransportCC,
+		URI:   uri,
+	}
+	return d.WithExtMap(e)
+}