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<!DOCTYPE html>
<html class="reftest-wait">
<head>
<meta charset="utf-8">
<title>Bug 2014868 - Reject SDP when MID changes at existing m-line index</title>
</head>
<body>
<script>
async function run() {
try {
const pc1 = new RTCPeerConnection();
const pc2 = new RTCPeerConnection();
pc1.addTransceiver("audio", { direction: "sendrecv" });
pc1.addTransceiver("video", { direction: "recvonly" });
pc1.createDataChannel("test");
let offer = await pc1.createOffer();
await pc1.setLocalDescription(offer);
await pc2.setRemoteDescription(offer);
let answer = await pc2.createAnswer();
await pc2.setLocalDescription(answer);
await pc1.setRemoteDescription(answer);
// Stop video transceiver to trigger recycling logic
for (const t of pc1.getTransceivers()) {
if (t.receiver.track.kind === "video") {
t.stop();
}
}
offer = await pc1.createOffer();
await pc1.setLocalDescription(offer);
await pc2.setRemoteDescription(offer);
answer = await pc2.createAnswer();
await pc2.setLocalDescription(answer);
await pc1.setRemoteDescription(answer);
// Munge the offer: insert a duplicate video m-line at the application m-line
// position. This displaces the application section and creates a media type
// mismatch at that index, testing that we reject invalid type changes.
const sdpLines = offer.sdp.split("\r\n");
let mLineCount = 0;
let insertIndex = -1;
for (let i = 0; i < sdpLines.length; i++) {
if (sdpLines[i].startsWith("m=")) {
mLineCount++;
if (mLineCount === 2) {
insertIndex = i;
}
}
}
// Duplicate the second m-line section with a changed MID
if (insertIndex !== -1) {
let endIndex = insertIndex + 1;
for (let i = insertIndex + 1; i < sdpLines.length; i++) {
if (sdpLines[i].startsWith("m=")) {
endIndex = i;
break;
}
}
if (endIndex === sdpLines.length) endIndex = sdpLines.length;
const mlineSection = sdpLines.slice(insertIndex, endIndex);
// Change the MID in the copied section
for (let i = 0; i < mlineSection.length; i++) {
if (mlineSection[i].startsWith("a=mid:")) {
mlineSection[i] = "a=mid:changed-mid";
break;
}
}
sdpLines.splice(endIndex, 0, ...mlineSection);
}
const modifiedAnswer = { type: "offer", sdp: sdpLines.join("\r\n") };
await pc1.setRemoteDescription(modifiedAnswer);
pc1.close();
pc2.close();
} catch (e) {
}
document.documentElement.removeAttribute("class");
}
run();
</script>
</body>
</html>