Add headers for SIP call transfer. (#926)

Author: dennwc

.changeset/strong-seahorses-hug.md

@@ -0,0 +1,6 @@
+---
+"@livekit/protocol": minor
+"github.com/livekit/protocol": minor
+---
+
+Add headers for SIP call transfer.

livekit/livekit_sip.pb.go

@@ -240,6 +240,9 @@ func (p *TransferSIPParticipantRequest) Validate() error {
 	if p.TransferTo == "" {
 		return errors.New("missing transfer to")
 	}
+	if err := validateHeaderKeys(p.Headers); err != nil {
+		return err
+	}
 
 	return nil
 }

livekit/livekit_sip.twirp.go

@@ -497,6 +497,9 @@ message TransferSIPParticipantRequest {
 
   // Optionally play dialtone to the SIP participant as an audible indicator of being transferred
   bool play_dialtone = 4;
+
+  // Add the following headers to the REFER SIP request.
+  map<string, string> headers = 5;
 }
 
 message SIPCallInfo {

livekit/sip.go

@@ -114,5 +114,8 @@ message InternalTransferSIPParticipantRequest {
 
   // Optionally play dialtone to the SIP participant as an audible indicator of being transferred
   bool play_dialtone = 3;
+
+  // Add the following headers to the REFER SIP request.
+  map<string, string> headers = 4;
 }
 

protobufs/livekit_sip.proto

@@ -98,3 +98,17 @@ func NewCreateSIPParticipantRequest(
 		MaxCallDuration:       req.MaxCallDuration,
 	}, nil
 }
+
+// NewTransferSIPParticipantRequest fills InternalTransferSIPParticipantRequest from
+// livekit.TransferSIPParticipantRequest.
+func NewTransferSIPParticipantRequest(
+	callID string,
+	req *livekit.TransferSIPParticipantRequest,
+) (*InternalTransferSIPParticipantRequest, error) {
+	return &InternalTransferSIPParticipantRequest{
+		SipCallId:    callID,
+		TransferTo:   req.TransferTo,
+		PlayDialtone: req.PlayDialtone,
+		Headers:      req.Headers,
+	}, nil
+}