84 lines
2.0 KiB
Go
84 lines
2.0 KiB
Go
package whip
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import (
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"fmt"
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"strconv"
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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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// ICEFragmentUnmarshal decodes an ICE fragment.
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func ICEFragmentUnmarshal(buf []byte) ([]*webrtc.ICECandidateInit, error) {
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buf = append([]byte("v=0\r\no=- 0 0 IN IP4 0.0.0.0\r\ns=-\r\nt=0 0\r\n"), buf...)
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var sdp sdp.SessionDescription
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err := sdp.Unmarshal(buf)
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if err != nil {
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return nil, err
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}
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var ret []*webrtc.ICECandidateInit
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for _, media := range sdp.MediaDescriptions {
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mid, ok := media.Attribute("mid")
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if !ok {
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return nil, fmt.Errorf("mid attribute is missing")
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}
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tmp, err := strconv.ParseUint(mid, 10, 16)
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if err != nil {
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return nil, fmt.Errorf("invalid mid attribute")
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}
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midNum := uint16(tmp)
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for _, attr := range media.Attributes {
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if attr.Key == "candidate" {
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ret = append(ret, &webrtc.ICECandidateInit{
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Candidate: attr.Value,
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SDPMid: &mid,
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SDPMLineIndex: &midNum,
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})
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}
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}
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}
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return ret, nil
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}
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// ICEFragmentMarshal encodes an ICE fragment.
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func ICEFragmentMarshal(offer string, candidates []*webrtc.ICECandidateInit) ([]byte, error) {
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var sdp sdp.SessionDescription
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err := sdp.Unmarshal([]byte(offer))
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if err != nil || len(sdp.MediaDescriptions) == 0 {
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return nil, err
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}
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firstMedia := sdp.MediaDescriptions[0]
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iceUfrag, _ := firstMedia.Attribute("ice-ufrag")
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icePwd, _ := firstMedia.Attribute("ice-pwd")
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candidatesByMedia := make(map[uint16][]*webrtc.ICECandidateInit)
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for _, candidate := range candidates {
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mid := *candidate.SDPMLineIndex
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candidatesByMedia[mid] = append(candidatesByMedia[mid], candidate)
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}
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frag := "a=ice-ufrag:" + iceUfrag + "\r\n" +
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"a=ice-pwd:" + icePwd + "\r\n"
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for mid, media := range sdp.MediaDescriptions {
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cbm, ok := candidatesByMedia[uint16(mid)]
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if ok {
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frag += "m=" + media.MediaName.String() + "\r\n" +
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"a=mid:" + strconv.FormatUint(uint64(mid), 10) + "\r\n"
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for _, candidate := range cbm {
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frag += "a=candidate:" + candidate.Candidate + "\r\n"
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}
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}
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}
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return []byte(frag), nil
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}
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