snapshot of https://github.com/pion/webrtc.git (main, 2026-09-15; blobs > 131072B omitted)

dtlsrole.go

@@ -0,0 +1,97 @@
+// SPDX-FileCopyrightText: 2026 The Pion community <https://pion.ly>
+// SPDX-License-Identifier: MIT
+
+package webrtc
+
+import (
+	"github.com/pion/sdp/v3"
+)
+
+// DTLSRole indicates the role of the DTLS transport.
+type DTLSRole byte
+
+const (
+	// DTLSRoleUnknown is the enum's zero-value.
+	DTLSRoleUnknown DTLSRole = iota
+
+	// DTLSRoleAuto defines the DTLS role is determined based on
+	// the resolved ICE role: the ICE controlled role acts as the DTLS
+	// client and the ICE controlling role acts as the DTLS server.
+	DTLSRoleAuto
+
+	// DTLSRoleClient defines the DTLS client role.
+	DTLSRoleClient
+
+	// DTLSRoleServer defines the DTLS server role.
+	DTLSRoleServer
+)
+
+const (
+	// https://tools.ietf.org/html/rfc5763
+	/*
+		The answerer MUST use either a
+		setup attribute value of setup:active or setup:passive.  Note that
+		if the answerer uses setup:passive, then the DTLS handshake will
+		not begin until the answerer is received, which adds additional
+		latency. setup:active allows the answer and the DTLS handshake to
+		occur in parallel.  Thus, setup:active is RECOMMENDED.
+	*/
+	defaultDtlsRoleAnswer = DTLSRoleClient
+	/*
+		The endpoint that is the offerer MUST use the setup attribute
+		value of setup:actpass and be prepared to receive a client_hello
+		before it receives the answer.
+	*/
+	defaultDtlsRoleOffer = DTLSRoleAuto
+)
+
+func (r DTLSRole) String() string {
+	switch r {
+	case DTLSRoleAuto:
+		return "auto"
+	case DTLSRoleClient:
+		return "client"
+	case DTLSRoleServer:
+		return "server"
+	default:
+		return ErrUnknownType.Error()
+	}
+}
+
+// Extract the dtls role from a session description. The decision is made from
+// the first role we we parse. If no role can be found we return DTLSRoleAuto.
+func dtlsRoleFromSDP(sessionDescription *sdp.SessionDescription) DTLSRole {
+	if sessionDescription == nil {
+		return DTLSRoleAuto
+	}
+
+	for _, mediaSection := range sessionDescription.MediaDescriptions {
+		for _, attribute := range mediaSection.Attributes {
+			if attribute.Key == "setup" {
+				switch attribute.Value {
+				case sdp.ConnectionRoleActive.String():
+					return DTLSRoleClient
+				case sdp.ConnectionRolePassive.String():
+					return DTLSRoleServer
+				default:
+					return DTLSRoleAuto
+				}
+			}
+		}
+	}
+
+	return DTLSRoleAuto
+}
+
+func connectionRoleFromDtlsRole(d DTLSRole) sdp.ConnectionRole {
+	switch d {
+	case DTLSRoleClient:
+		return sdp.ConnectionRoleActive
+	case DTLSRoleServer:
+		return sdp.ConnectionRolePassive
+	case DTLSRoleAuto:
+		return sdp.ConnectionRoleActpass
+	default:
+		return sdp.ConnectionRole(0)
+	}
+}