Squashed 'third_party/rawrtc/rawrtc/' content from commit aa3ae4b24

Change-Id: I38a655a4259b62f591334e90a1315bd4e7e4d8ec
git-subtree-dir: third_party/rawrtc/rawrtc
git-subtree-split: aa3ae4b247275cc6e69c30613b3a4ba7fdc82d1b
diff --git a/htdocs/ortc/index.html b/htdocs/ortc/index.html
new file mode 100644
index 0000000..f5e46c6
--- /dev/null
+++ b/htdocs/ortc/index.html
@@ -0,0 +1,92 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="utf-8">
+    <title>ORTC/WebRTC Interop Data Channel Example</title>
+</head>
+<style>
+textarea {
+}
+</style>
+<body>
+    <textarea cols="120" rows="20" id="local-parameters" onclick="this.select();" readonly></textarea>
+    <textarea cols="120" rows="20" id="remote-parameters"></textarea><br />
+    <button type="button" onclick="start(peer);" id="start" disabled>Start</button>
+
+    <script type="text/javascript" src="sdp.js"></script>
+    <script type="text/javascript" src="https://webrtc.github.io/adapter/adapter-latest.js"></script>
+    <script type="text/javascript" src="webrtc-rawrtc.js"></script>
+    <script type="text/javascript">
+        'use strict';
+        
+        let localParameters = document.getElementById('local-parameters');
+        let remoteParameters = document.getElementById('remote-parameters');
+        let startButton = document.getElementById('start');
+        
+        function getURLParameter(name) {
+            return decodeURIComponent((new RegExp('[?|&]' + name + '=' + '([^&;]+?)(&|#|;|$)').exec(location.search) || [null, ''])[1].replace(/\+/g, '%20')) || null;
+        }
+
+        function setRemoteParameters(peer) {
+            // Parse and apply the remote parameters
+            let parameters = JSON.parse(remoteParameters.value);
+            console.log('Remote parameters:', parameters);
+            peer.setRemoteParameters(parameters)
+            .then((parameters) => {
+                // Generate local parameters if controlled
+                if (peer instanceof ControlledPeer) {
+                    getLocalParameters(peer);
+                }
+            })
+            .catch((error) => {
+                console.error(error);
+            });
+        };
+
+        function getLocalParameters(peer) {
+            // Generate and show the local parameters
+            peer.getLocalParameters()
+            .then((parameters) => {
+                console.log('Local parameters:', parameters);
+                localParameters.value = JSON.stringify(parameters);
+            });
+        }
+
+        function createPeer(controllingParameter) {
+            let controlling = controllingParameter == 'true' || controllingParameter == '1';
+            console.log('Role: ICE-Controll' + (controlling ? 'ing' : 'ed'));
+            
+            // Create peer depending on the role
+            let peer = controlling ? new ControllingPeer() : new ControlledPeer();
+            peer.createPeerConnection();
+            let cat = peer.createDataChannel(peer.pc.createDataChannel('cat-noises', {
+                ordered: true,
+                negotiated: true,
+                id: 0
+            }));
+            peer.createDataChannel();
+            
+            // Create local parameters if we are the controlling peer.
+            // Keep in mind this still uses offer/answer in the background, thus this
+            // limitation which does not exist for ORTC but does for WebRTC.
+            if (controlling) {
+                getLocalParameters(peer);
+            }
+            
+            return peer;
+        }
+        
+        function start(peer) {
+            // Apply remote parameters
+            // For the controlled peer, this will automatically generate local parameters
+            setRemoteParameters(peer);
+            startButton.disabled = true;
+        }
+        
+        // Create peer
+        // Determine role from GET parameter (?controlling=true|false)
+        let peer = createPeer(getURLParameter('controlling'));
+        startButton.disabled = false;
+    </script>
+</body>
+</html>
diff --git a/htdocs/ortc/sdp.js b/htdocs/ortc/sdp.js
new file mode 100644
index 0000000..0dd2472
--- /dev/null
+++ b/htdocs/ortc/sdp.js
@@ -0,0 +1,549 @@
+/*
+ * Copyright Philipp Hancke
+ * License: MIT
+ * Source: https://github.com/fippo/sdp
+ *
+ * Extended by Lennart Grahl
+ */
+
+/* eslint-env node */
+'use strict';
+
+// SDP helpers.
+var SDPUtils = {};
+
+// Generate an alphanumeric identifier for cname or mids.
+// TODO: use UUIDs instead? https://gist.github.com/jed/982883
+SDPUtils.generateIdentifier = function() {
+  return Math.random().toString(36).substr(2, 10);
+};
+
+// The RTCP CNAME used by all peerconnections from the same JS.
+SDPUtils.localCName = SDPUtils.generateIdentifier();
+
+// Splits SDP into lines, dealing with both CRLF and LF.
+SDPUtils.splitLines = function(blob) {
+  return blob.trim().split('\n').map(function(line) {
+    return line.trim();
+  });
+};
+// Splits SDP into sessionpart and mediasections. Ensures CRLF.
+SDPUtils.splitSections = function(blob) {
+  var parts = blob.split('\nm=');
+  return parts.map(function(part, index) {
+    return (index > 0 ? 'm=' + part : part).trim() + '\r\n';
+  });
+};
+
+// Returns lines that start with a certain prefix.
+SDPUtils.matchPrefix = function(blob, prefix) {
+  return SDPUtils.splitLines(blob).filter(function(line) {
+    return line.indexOf(prefix) === 0;
+  });
+};
+
+// Parses an ICE candidate line. Sample input:
+// candidate:702786350 2 udp 41819902 8.8.8.8 60769 typ relay raddr 8.8.8.8
+// rport 55996"
+SDPUtils.parseCandidate = function(line) {
+  var parts;
+  // Parse both variants.
+  if (line.indexOf('a=candidate:') === 0) {
+    parts = line.substring(12).split(' ');
+  } else {
+    parts = line.substring(10).split(' ');
+  }
+
+  var candidate = {
+    foundation: parts[0],
+    component: parts[1],
+    protocol: parts[2].toLowerCase(),
+    priority: parseInt(parts[3], 10),
+    ip: parts[4],
+    port: parseInt(parts[5], 10),
+    // skip parts[6] == 'typ'
+    type: parts[7]
+  };
+
+  for (var i = 8; i < parts.length; i += 2) {
+    switch (parts[i]) {
+      case 'raddr':
+        candidate.relatedAddress = parts[i + 1];
+        break;
+      case 'rport':
+        candidate.relatedPort = parseInt(parts[i + 1], 10);
+        break;
+      case 'tcptype':
+        candidate.tcpType = parts[i + 1];
+        break;
+      default: // Unknown extensions are silently ignored.
+        break;
+    }
+  }
+  return candidate;
+};
+
+// Translates a candidate object into SDP candidate attribute.
+SDPUtils.writeCandidate = function(candidate) {
+  var sdp = [];
+  sdp.push(candidate.foundation);
+  sdp.push(candidate.component);
+  sdp.push(candidate.protocol.toUpperCase());
+  sdp.push(candidate.priority);
+  sdp.push(candidate.ip);
+  sdp.push(candidate.port);
+
+  var type = candidate.type;
+  sdp.push('typ');
+  sdp.push(type);
+  if (type !== 'host' && candidate.relatedAddress &&
+      candidate.relatedPort) {
+    sdp.push('raddr');
+    sdp.push(candidate.relatedAddress); // was: relAddr
+    sdp.push('rport');
+    sdp.push(candidate.relatedPort); // was: relPort
+  }
+  if (candidate.tcpType && candidate.protocol.toLowerCase() === 'tcp') {
+    sdp.push('tcptype');
+    sdp.push(candidate.tcpType);
+  }
+  return 'candidate:' + sdp.join(' ');
+};
+
+// Parses an rtpmap line, returns RTCRtpCoddecParameters. Sample input:
+// a=rtpmap:111 opus/48000/2
+SDPUtils.parseRtpMap = function(line) {
+  var parts = line.substr(9).split(' ');
+  var parsed = {
+    payloadType: parseInt(parts.shift(), 10) // was: id
+  };
+
+  parts = parts[0].split('/');
+
+  parsed.name = parts[0];
+  parsed.clockRate = parseInt(parts[1], 10); // was: clockrate
+  // was: channels
+  parsed.numChannels = parts.length === 3 ? parseInt(parts[2], 10) : 1;
+  return parsed;
+};
+
+// Generate an a=rtpmap line from RTCRtpCodecCapability or
+// RTCRtpCodecParameters.
+SDPUtils.writeRtpMap = function(codec) {
+  var pt = codec.payloadType;
+  if (codec.preferredPayloadType !== undefined) {
+    pt = codec.preferredPayloadType;
+  }
+  return 'a=rtpmap:' + pt + ' ' + codec.name + '/' + codec.clockRate +
+      (codec.numChannels !== 1 ? '/' + codec.numChannels : '') + '\r\n';
+};
+
+// Parses an a=extmap line (headerextension from RFC 5285). Sample input:
+// a=extmap:2 urn:ietf:params:rtp-hdrext:toffset
+SDPUtils.parseExtmap = function(line) {
+  var parts = line.substr(9).split(' ');
+  return {
+    id: parseInt(parts[0], 10),
+    uri: parts[1]
+  };
+};
+
+// Generates a=extmap line from RTCRtpHeaderExtensionParameters or
+// RTCRtpHeaderExtension.
+SDPUtils.writeExtmap = function(headerExtension) {
+  return 'a=extmap:' + (headerExtension.id || headerExtension.preferredId) +
+      ' ' + headerExtension.uri + '\r\n';
+};
+
+// Parses an ftmp line, returns dictionary. Sample input:
+// a=fmtp:96 vbr=on;cng=on
+// Also deals with vbr=on; cng=on
+SDPUtils.parseFmtp = function(line) {
+  var parsed = {};
+  var kv;
+  var parts = line.substr(line.indexOf(' ') + 1).split(';');
+  for (var j = 0; j < parts.length; j++) {
+    kv = parts[j].trim().split('=');
+    parsed[kv[0].trim()] = kv[1];
+  }
+  return parsed;
+};
+
+// Generates an a=ftmp line from RTCRtpCodecCapability or RTCRtpCodecParameters.
+SDPUtils.writeFmtp = function(codec) {
+  var line = '';
+  var pt = codec.payloadType;
+  if (codec.preferredPayloadType !== undefined) {
+    pt = codec.preferredPayloadType;
+  }
+  if (codec.parameters && Object.keys(codec.parameters).length) {
+    var params = [];
+    Object.keys(codec.parameters).forEach(function(param) {
+      params.push(param + '=' + codec.parameters[param]);
+    });
+    line += 'a=fmtp:' + pt + ' ' + params.join(';') + '\r\n';
+  }
+  return line;
+};
+
+// Parses an rtcp-fb line, returns RTCPRtcpFeedback object. Sample input:
+// a=rtcp-fb:98 nack rpsi
+SDPUtils.parseRtcpFb = function(line) {
+  var parts = line.substr(line.indexOf(' ') + 1).split(' ');
+  return {
+    type: parts.shift(),
+    parameter: parts.join(' ')
+  };
+};
+// Generate a=rtcp-fb lines from RTCRtpCodecCapability or RTCRtpCodecParameters.
+SDPUtils.writeRtcpFb = function(codec) {
+  var lines = '';
+  var pt = codec.payloadType;
+  if (codec.preferredPayloadType !== undefined) {
+    pt = codec.preferredPayloadType;
+  }
+  if (codec.rtcpFeedback && codec.rtcpFeedback.length) {
+    // FIXME: special handling for trr-int?
+    codec.rtcpFeedback.forEach(function(fb) {
+      lines += 'a=rtcp-fb:' + pt + ' ' + fb.type +
+          (fb.parameter && fb.parameter.length ? ' ' + fb.parameter : '') +
+          '\r\n';
+    });
+  }
+  return lines;
+};
+
+// Parses an RFC 5576 ssrc media attribute. Sample input:
+// a=ssrc:3735928559 cname:something
+SDPUtils.parseSsrcMedia = function(line) {
+  var sp = line.indexOf(' ');
+  var parts = {
+    ssrc: parseInt(line.substr(7, sp - 7), 10)
+  };
+  var colon = line.indexOf(':', sp);
+  if (colon > -1) {
+    parts.attribute = line.substr(sp + 1, colon - sp - 1);
+    parts.value = line.substr(colon + 1);
+  } else {
+    parts.attribute = line.substr(sp + 1);
+  }
+  return parts;
+};
+
+// Extracts SCTP capabilities from SDP media section or sessionpart.
+SDPUtils.getSctpCapabilities = function(mediaSection, sessionpart) {
+  var lines = SDPUtils.splitLines(mediaSection);
+  // Search in session part, too.
+  lines = lines.concat(SDPUtils.splitLines(sessionpart));
+  var maxMessageSize = lines.filter(function(line) {
+    return line.indexOf('a=max-message-size:') === 0;
+  });
+  // TODO: Use 65536 once Firefox has disabled PPID-based fragmentation
+  //       see: https://lgrahl.de/articles/demystifying-webrtc-dc-size-limit.html
+  maxMessageSize = maxMessageSize.length ? parseInt(maxMessageSize[0].substr(19)) : 16384;
+  return {
+    maxMessageSize: maxMessageSize
+  };
+};
+
+// Serializes SCTP capabilities to SDP.
+SDPUtils.writeSctpCapabilities = function(capabilities) {
+  return 'a=max-message-size:' + capabilities.maxMessageSize + '\r\n'; // (03)
+};
+
+// Extracts SCTP port from SDP media section or sessionpart.
+SDPUtils.getSctpPort = function(mediaSection, sessionpart) {
+  var lines = SDPUtils.splitLines(mediaSection);
+  // Search in session part, too.
+  lines = lines.concat(SDPUtils.splitLines(sessionpart));
+  var port = lines.filter(function(line) {
+    return line.indexOf('a=sctp-port:') === 0;
+  });
+  port = port.length ? parseInt(port[0].substr(12), 10) : 5000;
+  return port;
+};
+
+// Serializes SCTP port to SDP.
+SDPUtils.writeSctpPort = function(port) {
+  // TODO: Enable (chromium can't cope with it)
+  // return 'a=sctp-port:' + (port ? port : 5000) + '\r\n'; // (03)
+  return '';
+};
+
+// Extracts DTLS parameters from SDP media section or sessionpart.
+// FIXME: for consistency with other functions this should only
+//   get the fingerprint line as input. See also getIceParameters.
+SDPUtils.getDtlsParameters = function(mediaSection, sessionpart) {
+  var lines = SDPUtils.splitLines(mediaSection);
+  // Search in session part, too.
+  lines = lines.concat(SDPUtils.splitLines(sessionpart));
+  var fpLine = lines.filter(function(line) {
+    return line.indexOf('a=fingerprint:') === 0;
+  })[0].substr(14);
+  // Note: a=setup line is ignored since we use the 'auto' role.
+  var dtlsParameters = {
+    role: 'auto',
+    fingerprints: [{
+      algorithm: fpLine.split(' ')[0],
+      value: fpLine.split(' ')[1]
+    }]
+  };
+  return dtlsParameters;
+};
+
+// Serializes DTLS parameters to SDP.
+SDPUtils.writeDtlsParameters = function(params, setupType) {
+  var sdp = 'a=setup:' + setupType + '\r\n';
+  params.fingerprints.forEach(function(fp) {
+    sdp += 'a=fingerprint:' + fp.algorithm + ' ' + fp.value + '\r\n';
+  });
+  return sdp;
+};
+// Parses ICE information from SDP media section or sessionpart.
+// FIXME: for consistency with other functions this should only
+//   get the ice-ufrag and ice-pwd lines as input.
+SDPUtils.getIceParameters = function(mediaSection, sessionpart) {
+  var lines = SDPUtils.splitLines(mediaSection);
+  // Search in session part, too.
+  lines = lines.concat(SDPUtils.splitLines(sessionpart));
+  var iceParameters = {
+    usernameFragment: lines.filter(function(line) {
+      return line.indexOf('a=ice-ufrag:') === 0;
+    })[0].substr(12),
+    password: lines.filter(function(line) {
+      return line.indexOf('a=ice-pwd:') === 0;
+    })[0].substr(10)
+  };
+  return iceParameters;
+};
+
+// Serializes ICE parameters to SDP.
+SDPUtils.writeIceParameters = function(params) {
+  return 'a=ice-ufrag:' + params.usernameFragment + '\r\n' +
+      'a=ice-pwd:' + params.password + '\r\n';
+};
+
+// Parses the SDP media section and returns RTCRtpParameters.
+SDPUtils.parseRtpParameters = function(mediaSection) {
+  var description = {
+    codecs: [],
+    headerExtensions: [],
+    fecMechanisms: [],
+    rtcp: []
+  };
+  var lines = SDPUtils.splitLines(mediaSection);
+  var mline = lines[0].split(' ');
+  for (var i = 3; i < mline.length; i++) { // find all codecs from mline[3..]
+    var pt = mline[i];
+    var rtpmapline = SDPUtils.matchPrefix(
+        mediaSection, 'a=rtpmap:' + pt + ' ')[0];
+    if (rtpmapline) {
+      var codec = SDPUtils.parseRtpMap(rtpmapline);
+      var fmtps = SDPUtils.matchPrefix(
+          mediaSection, 'a=fmtp:' + pt + ' ');
+      // Only the first a=fmtp:<pt> is considered.
+      codec.parameters = fmtps.length ? SDPUtils.parseFmtp(fmtps[0]) : {};
+      codec.rtcpFeedback = SDPUtils.matchPrefix(
+          mediaSection, 'a=rtcp-fb:' + pt + ' ')
+          .map(SDPUtils.parseRtcpFb);
+      description.codecs.push(codec);
+      // parse FEC mechanisms from rtpmap lines.
+      switch (codec.name.toUpperCase()) {
+        case 'RED':
+        case 'ULPFEC':
+          description.fecMechanisms.push(codec.name.toUpperCase());
+          break;
+        default: // only RED and ULPFEC are recognized as FEC mechanisms.
+          break;
+      }
+    }
+  }
+  SDPUtils.matchPrefix(mediaSection, 'a=extmap:').forEach(function(line) {
+    description.headerExtensions.push(SDPUtils.parseExtmap(line));
+  });
+  // FIXME: parse rtcp.
+  return description;
+};
+
+// Generates parts of the SDP media section describing the capabilities /
+// parameters.
+SDPUtils.writeRtpDescription = function(kind, caps) {
+  var sdp = '';
+
+  // Build the mline.
+  sdp += 'm=' + kind + ' ';
+  sdp += caps.codecs.length > 0 ? '9' : '0'; // reject if no codecs.
+  sdp += ' UDP/TLS/RTP/SAVPF ';
+  sdp += caps.codecs.map(function(codec) {
+        if (codec.preferredPayloadType !== undefined) {
+          return codec.preferredPayloadType;
+        }
+        return codec.payloadType;
+      }).join(' ') + '\r\n';
+
+  sdp += 'c=IN IP4 0.0.0.0\r\n';
+  sdp += 'a=rtcp:9 IN IP4 0.0.0.0\r\n';
+
+  // Add a=rtpmap lines for each codec. Also fmtp and rtcp-fb.
+  caps.codecs.forEach(function(codec) {
+    sdp += SDPUtils.writeRtpMap(codec);
+    sdp += SDPUtils.writeFmtp(codec);
+    sdp += SDPUtils.writeRtcpFb(codec);
+  });
+  var maxptime = 0;
+  caps.codecs.forEach(function(codec) {
+    if (codec.maxptime > maxptime) {
+      maxptime = codec.maxptime;
+    }
+  });
+  if (maxptime > 0) {
+    sdp += 'a=maxptime:' + maxptime + '\r\n';
+  }
+  sdp += 'a=rtcp-mux\r\n';
+
+  caps.headerExtensions.forEach(function(extension) {
+    sdp += SDPUtils.writeExtmap(extension);
+  });
+  // FIXME: write fecMechanisms.
+  return sdp;
+};
+
+// Parses the SDP media section and returns an array of
+// RTCRtpEncodingParameters.
+SDPUtils.parseRtpEncodingParameters = function(mediaSection) {
+  var encodingParameters = [];
+  var description = SDPUtils.parseRtpParameters(mediaSection);
+  var hasRed = description.fecMechanisms.indexOf('RED') !== -1;
+  var hasUlpfec = description.fecMechanisms.indexOf('ULPFEC') !== -1;
+
+  // filter a=ssrc:... cname:, ignore PlanB-msid
+  var ssrcs = SDPUtils.matchPrefix(mediaSection, 'a=ssrc:')
+      .map(function(line) {
+        return SDPUtils.parseSsrcMedia(line);
+      })
+      .filter(function(parts) {
+        return parts.attribute === 'cname';
+      });
+  var primarySsrc = ssrcs.length > 0 && ssrcs[0].ssrc;
+  var secondarySsrc;
+
+  var flows = SDPUtils.matchPrefix(mediaSection, 'a=ssrc-group:FID')
+      .map(function(line) {
+        var parts = line.split(' ');
+        parts.shift();
+        return parts.map(function(part) {
+          return parseInt(part, 10);
+        });
+      });
+  if (flows.length > 0 && flows[0].length > 1 && flows[0][0] === primarySsrc) {
+    secondarySsrc = flows[0][1];
+  }
+
+  description.codecs.forEach(function(codec) {
+    if (codec.name.toUpperCase() === 'RTX' && codec.parameters.apt) {
+      var encParam = {
+        ssrc: primarySsrc,
+        codecPayloadType: parseInt(codec.parameters.apt, 10),
+        rtx: {
+          payloadType: codec.payloadType,
+          ssrc: secondarySsrc
+        }
+      };
+      encodingParameters.push(encParam);
+      if (hasRed) {
+        encParam = JSON.parse(JSON.stringify(encParam));
+        encParam.fec = {
+          ssrc: secondarySsrc,
+          mechanism: hasUlpfec ? 'red+ulpfec' : 'red'
+        };
+        encodingParameters.push(encParam);
+      }
+    }
+  });
+  if (encodingParameters.length === 0 && primarySsrc) {
+    encodingParameters.push({
+      ssrc: primarySsrc
+    });
+  }
+
+  // we support both b=AS and b=TIAS but interpret AS as TIAS.
+  var bandwidth = SDPUtils.matchPrefix(mediaSection, 'b=');
+  if (bandwidth.length) {
+    if (bandwidth[0].indexOf('b=TIAS:') === 0) {
+      bandwidth = parseInt(bandwidth[0].substr(7), 10);
+    } else if (bandwidth[0].indexOf('b=AS:') === 0) {
+      bandwidth = parseInt(bandwidth[0].substr(5), 10);
+    }
+    encodingParameters.forEach(function(params) {
+      params.maxBitrate = bandwidth;
+    });
+  }
+  return encodingParameters;
+};
+
+SDPUtils.writeSessionBoilerplate = function() {
+  // FIXME: sess-id should be an NTP timestamp.
+  return 'v=0\r\n' +
+      'o=thisisadapterortc 8169639915646943137 2 IN IP4 127.0.0.1\r\n' +
+      's=-\r\n' +
+      't=0 0\r\n';
+};
+
+SDPUtils.writeMediaSection = function(transceiver, caps, type, stream) {
+  var sdp = SDPUtils.writeRtpDescription(transceiver.kind, caps);
+
+  // Map ICE parameters (ufrag, pwd) to SDP.
+  sdp += SDPUtils.writeIceParameters(
+      transceiver.iceGatherer.getLocalParameters());
+
+  // Map DTLS parameters to SDP.
+  sdp += SDPUtils.writeDtlsParameters(
+      transceiver.dtlsTransport.getLocalParameters(),
+      type === 'offer' ? 'actpass' : 'active');
+
+  sdp += 'a=mid:' + transceiver.mid + '\r\n';
+
+  if (transceiver.rtpSender && transceiver.rtpReceiver) {
+    sdp += 'a=sendrecv\r\n';
+  } else if (transceiver.rtpSender) {
+    sdp += 'a=sendonly\r\n';
+  } else if (transceiver.rtpReceiver) {
+    sdp += 'a=recvonly\r\n';
+  } else {
+    sdp += 'a=inactive\r\n';
+  }
+
+  // FIXME: for RTX there might be multiple SSRCs. Not implemented in Edge yet.
+  if (transceiver.rtpSender) {
+    var msid = 'msid:' + stream.id + ' ' +
+        transceiver.rtpSender.track.id + '\r\n';
+    sdp += 'a=' + msid;
+    sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].ssrc +
+        ' ' + msid;
+  }
+  // FIXME: this should be written by writeRtpDescription.
+  sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].ssrc +
+      ' cname:' + SDPUtils.localCName + '\r\n';
+  return sdp;
+};
+
+// Gets the direction from the mediaSection or the sessionpart.
+SDPUtils.getDirection = function(mediaSection, sessionpart) {
+  // Look for sendrecv, sendonly, recvonly, inactive, default to sendrecv.
+  var lines = SDPUtils.splitLines(mediaSection);
+  for (var i = 0; i < lines.length; i++) {
+    switch (lines[i]) {
+      case 'a=sendrecv':
+      case 'a=sendonly':
+      case 'a=recvonly':
+      case 'a=inactive':
+        return lines[i].substr(2);
+      default:
+        // FIXME: What should happen here?
+    }
+  }
+  if (sessionpart) {
+    return SDPUtils.getDirection(sessionpart);
+  }
+  return 'sendrecv';
+};
diff --git a/htdocs/ortc/webrtc-rawrtc.js b/htdocs/ortc/webrtc-rawrtc.js
new file mode 100644
index 0000000..bad70e0
--- /dev/null
+++ b/htdocs/ortc/webrtc-rawrtc.js
@@ -0,0 +1,396 @@
+'use strict';
+
+class Peer {
+    constructor() {
+        this.pc = null;
+        this.localMid = null;
+        this.localCandidates = [];
+        this.localParameters = null;
+        this.localDescription = null;
+        this.remoteParameters = null;
+        this.remoteDescription = null;
+        var _waitGatheringComplete = {};
+        _waitGatheringComplete.promise = new Promise((resolve, reject) => {
+            _waitGatheringComplete.resolve = resolve;
+            _waitGatheringComplete.reject = reject;
+        });
+        this._waitGatheringComplete = _waitGatheringComplete;
+        this.dc = {}
+    }
+
+    createPeerConnection() {
+        if (this.pc) {
+            console.warn('RTCPeerConnection already created');
+            return this.pc;
+        }
+
+        var self = this;
+
+        // Create peer connection
+        var pc = new RTCPeerConnection({
+            iceServers: [{
+                urls: 'stun:stun.l.google.com:19302'
+            }]
+        });
+
+        // Bind peer connection events
+        pc.onnegotiationneeded = function(event) {
+            console.log('Negotiation needed')
+        };
+        pc.onicecandidate = function(event) {
+            if (event.candidate) {
+                console.log('Gathered candidate:', event.candidate);
+                self.localCandidates.push(event.candidate);
+            } else {
+                console.log('Gathering complete');
+                self._waitGatheringComplete.resolve();
+            }
+        };
+        pc.onicecandidateerror = function(event) {
+            console.error('ICE candidate error:', event.errorText);
+        };
+        pc.onsignalingstatechange = function(event) {
+            console.log('Signaling state changed to:', pc.signalingState);
+        };
+        pc.oniceconnectionstatechange = function(event) {
+            console.log('ICE connection state changed to:', pc.iceConnectionState);
+        };
+        pc.onicegatheringstatechange = function(event) {
+            console.log('ICE gathering state changed to:', pc.iceGatheringState);
+        };
+        pc.onconnectionstatechange = function(event) {
+            console.log('Connection state changed to:', pc.connectionState);
+        };
+        pc.ondatachannel = function(event) {
+            self.createDataChannel(event.channel);
+        };
+
+        this.pc = pc;
+        return pc;
+    }
+
+    createDataChannel(dc) {
+        // Create data channel
+        dc = (typeof dc !== 'undefined') ? dc : this.pc.createDataChannel('example-channel', {
+            ordered: true
+        });
+
+        // Bind data channel events
+        dc.onopen = function(event) {
+            console.log('Data channel', dc.label, '(', dc.id, ')', 'open');
+            // Send 'hello'
+            dc.send('Hello from WebRTC on', navigator.userAgent);
+        };
+        dc.onbufferedamountlow = function(event) {
+            console.log('Data channel', dc.label, '(', dc.id, ')', 'buffered amount low');
+        };
+        dc.onerror = function(event) {
+            console.error('Data channel', dc.label, '(', dc.id, ')', 'error:', event);
+        };
+        dc.onclose = function(event) {
+            console.log('Data channel', dc.label, '(', dc.id, ')', 'closed');
+        };
+        dc.onmessage = function(event) {
+            var length = event.data.size || event.data.byteLength || event.data.length;
+            console.info('Data channel', dc.label, '(', dc.id, ')', 'message size:', length);
+        };
+
+        // Store channel
+        this.dc[dc.label] = dc;
+
+        return dc;
+    }
+
+    getLocalParameters() {
+        return new Promise((resolve, reject) => {
+            var error;
+            var self = this;
+
+            if (!this.localDescription) {
+                error = 'Must create offer/answer';
+                console.error(error);
+                reject(error);
+                return;
+            }
+
+            // Initialise parameters
+            var parameters = {
+                iceParameters: null,
+                iceCandidates: [],
+                dtlsParameters: null,
+                sctpParameters: null,
+            };
+
+            // Split sections
+            var sections = SDPUtils.splitSections(this.localDescription.sdp);
+            var session = sections.shift();
+
+            // Go through media sections
+            sections.forEach(function(mediaSection, sdpMLineIndex) {
+                // TODO: Ignore anything else but data transports
+
+                // Get mid
+                // TODO: This breaks with multiple transceivers
+                if (!self.localMid) {
+                    var mid = SDPUtils.matchPrefix(mediaSection, 'a=mid:');
+                    if (mid.length > 0) {
+                        self.localMid = mid[0].substr(6);
+                    }
+                }
+
+                // Get ICE parameters
+                if (!parameters.iceParameters) {
+                    parameters.iceParameters = SDPUtils.getIceParameters(mediaSection, session);
+                }
+
+                // Get DTLS parameters
+                if (!parameters.dtlsParameters) {
+                    parameters.dtlsParameters = SDPUtils.getDtlsParameters(mediaSection, session);
+                }
+
+                // Get SCTP parameters
+                if (!parameters.sctpParameters) {
+                    parameters.sctpParameters = SDPUtils.getSctpCapabilities(mediaSection, session);
+                    parameters.sctpParameters.port = SDPUtils.getSctpPort(mediaSection, session);
+                }
+            });
+
+            // ICE lite parameter
+            if (!parameters.iceParameters
+                    || !parameters.dtlsParameters
+                    || !parameters.sctpParameters) {
+                error = 'Could not retrieve required parameters from local description';
+                console.error(error);
+                reject(error);
+                return;
+            }
+            parameters.iceParameters.iceLite =
+                SDPUtils.matchPrefix(session, 'a=ice-lite').length > 0;
+
+            // Get ICE candidates
+            this._waitGatheringComplete.promise.then(() => {
+                // Add ICE candidates
+                for (var sdpCandidate of self.localCandidates) {
+                    var candidate = SDPUtils.parseCandidate(sdpCandidate.candidate);
+                    parameters.iceCandidates.push(candidate);
+                }
+
+                // Add ICE candidate complete sentinel
+                // parameters.iceCandidates.push({complete: true}); // TODO
+
+                // Done
+                resolve(parameters);
+            });
+        });
+    }
+
+    setRemoteParameters(parameters, type, localMid = null) {
+        return new Promise((resolve, reject) => {
+            if (this.remoteDescription) {
+                resolve(this.remoteDescription);
+                return;
+            }
+
+            if (!this.pc) {
+                console.error('Must create RTCPeerConnection instance');
+                return;
+            }
+
+            if (!localMid) {
+                localMid = this.localMid;
+            }
+            this.remoteParameters = parameters;
+
+            // Translate DTLS role
+            // TODO: This somehow didn't make it into SDPUtils
+            var setupType;
+            switch (parameters.dtlsParameters.role) {
+                case 'client':
+                    setupType = 'active';
+                    break;
+                case 'server':
+                    setupType = 'passive';
+                    break;
+                default:
+                    // We map 'offer' to 'controlling' and 'answer' to 'controlled',
+                    // so rawrtc will take 'server' if offering and 'client' if answering
+                    // as specified by the ORTC spec
+                    switch (type) {
+                        case 'offer':
+                            // WebRTC requires actpass in offer
+                            setupType = 'actpass';
+                            break;
+                        case 'answer':
+                            setupType = 'active';
+                            break;
+                    }
+                    break;
+            }
+
+            // Write session section
+            var sdp = SDPUtils.writeSessionBoilerplate();
+            sdp += 'a=group:BUNDLE ' + localMid + '\r\n';
+            sdp += 'a=ice-options:trickle\r\n';
+            if (parameters.iceParameters.iceLite) {
+                sdp += 'a=ice-lite\r\n';
+            }
+
+            // Write media section
+            // TODO: Replace
+            // sdp += 'm=application 9 UDP/DTLS/SCTP webrtc-datachannel\r\n'; // (03)
+            sdp += 'm=application 9 DTLS/SCTP ' + parameters.sctpParameters.port + '\r\n'; // (01)
+            sdp += 'c=IN IP4 0.0.0.0\r\n';
+            sdp += 'a=mid:' + localMid + '\r\n';
+            sdp += 'a=sendrecv\r\n';
+
+            // SCTP part
+            sdp += SDPUtils.writeSctpCapabilities(parameters.sctpParameters);
+            sdp += SDPUtils.writeSctpPort(parameters.sctpParameters.port);
+            sdp += 'a=sctpmap:' + parameters.sctpParameters.port + ' webrtc-datachannel 65535\r\n'; // (01)
+
+            // DTLS part
+            sdp += SDPUtils.writeDtlsParameters(parameters.dtlsParameters, setupType);
+
+            // ICE part
+            sdp += 'a=connection:new\r\n'; // (03)
+            sdp += SDPUtils.writeIceParameters(parameters.iceParameters);
+
+            // Done
+            console.log('Remote description:\n' + sdp);
+
+            // Set remote description
+            this.pc.setRemoteDescription({type: type, sdp: sdp})
+            .then(() => {
+                console.log('Remote description:\n' + this.pc.remoteDescription.sdp);
+                this.remoteDescription = this.pc.remoteDescription;
+
+                // Add ICE candidates
+                for (var iceCandidate of parameters.iceCandidates) {
+                    // Add component which ORTC doesn't have
+                    // Note: We choose RTP as it doesn't actually matter for us
+                    iceCandidate.component = 1; // RTP
+
+                    // Create
+                    var candidate = new RTCIceCandidate({
+                        candidate: SDPUtils.writeCandidate(iceCandidate),
+                        sdpMLineIndex: 0, // TODO: Fix
+                        sdpMid: localMid // TODO: Fix
+                    });
+
+                    // Add
+                    console.log(candidate.candidate);
+                    this.pc.addIceCandidate(candidate)
+                    .then(() => {
+                        console.log('Added remote candidate', candidate);
+                    });
+                }
+
+                // It's trickle ICE, no need to wait for candidates to be added
+                resolve();
+            })
+            .catch((error) => {
+                reject(error);
+            });
+        });
+    }
+
+    start() {}
+}
+
+class ControllingPeer extends Peer {
+    getLocalParameters() {
+        return new Promise((resolve, reject) => {
+            if (!this.pc) {
+                var error = 'Must create RTCPeerConnection instance';
+                console.error(error);
+                reject(error);
+                return;
+            }
+
+            var getLocalParameters = () => {
+                // Return parameters
+                super.getLocalParameters()
+                .then((parameters) => {
+                    this.localParameters = parameters;
+                    resolve(parameters);
+                })
+                .catch((error) => {
+                    reject(error);
+                });
+            };
+
+            // Create offer
+            if (!this.localDescription) {
+                this.pc.createOffer()
+                .then((description) => {
+                    return this.pc.setLocalDescription(description);
+                })
+                .then(() => {
+                    console.log('Local description:\n' + this.pc.localDescription.sdp);
+                    this.localDescription = this.pc.localDescription;
+                    getLocalParameters();
+                })
+                .catch((error) => {
+                    reject(error);
+                });
+            } else {
+                getLocalParameters();
+            }
+        });
+    }
+
+    setRemoteParameters(parameters, localMid = null) {
+        return super.setRemoteParameters(parameters, 'answer', localMid);
+    }
+}
+
+class ControlledPeer extends Peer {
+    getLocalParameters() {
+        return new Promise((resolve, reject) => {
+            var error;
+
+            if (!this.pc) {
+                error = 'Must create RTCPeerConnection instance';
+                console.error(error);
+                reject(error);
+                return;
+            }
+            if (!this.remoteDescription) {
+                error = 'Must have remote description';
+                console.error(error);
+                reject(error);
+                return;
+            }
+
+            var getLocalParameters = () => {
+                // Return parameters
+                super.getLocalParameters()
+                .then((parameters) => {
+                    resolve(parameters);
+                })
+                .catch((error) => {
+                    reject(error);
+                });
+            };
+
+            // Create answer
+            if (!this.localDescription) {
+                this.pc.createAnswer()
+                .then((description) => {
+                    return this.pc.setLocalDescription(description);
+                })
+                .then(() => {
+                    console.log('Local description:\n' + this.pc.localDescription.sdp);
+                    this.localDescription = this.pc.localDescription;
+                    getLocalParameters();
+                });
+            } else {
+                getLocalParameters();
+            }
+        });
+    }
+
+    setRemoteParameters(parameters, localMid = null) {
+        return super.setRemoteParameters(parameters, 'offer', localMid);
+    }
+}
diff --git a/htdocs/webrtc/index.html b/htdocs/webrtc/index.html
new file mode 100644
index 0000000..f8b27b9
--- /dev/null
+++ b/htdocs/webrtc/index.html
@@ -0,0 +1,275 @@
+<!DOCTYPE html>
+<html>
+<head lang="en">
+    <meta charset="UTF-8">
+    <title>WebRTC Data Channel Example</title>
+    <style>
+        @keyframes new-fade {
+            0% {
+                background-color: #fffb85;
+            }
+            100% {
+                background-color: transparent;
+            }
+        }
+
+        html, body {
+            margin: 0;
+            padding: 0;
+            height: 100%;
+        }
+        body {
+            height: 100vh;
+            display: flex;
+        }
+
+        main {
+            width: 100%;
+            display: flex;
+            flex-grow: 1;
+            flex-wrap: nowrap;
+        }
+
+        section, aside {
+            padding: 5px;
+            flex-grow: 1;
+            flex-basis: 0;
+        }
+        aside {
+            overflow-y: auto;
+        }
+
+        section textarea {
+            width: 100%;
+        }
+
+        #log {
+            margin: 0;
+            padding: 0;
+            flex-grow: 1;
+            flex-basis: 0;
+        }
+        #log > * {
+            margin: 2px 0;
+            padding: 0 6px;
+            animation: new-fade 1.5s ease-out 1;
+        }
+        #log .debug, #log .log {
+            border-left: 2px solid lightgrey;
+        }
+        #log .error {
+            border-left: 2px solid red;
+        }
+        #log .info {
+            border-left: 2px solid cornflowerblue;
+        }
+        #log .warn {
+            border-left: 2px solid orange;
+        }
+    </style>
+</head>
+<body>
+
+<main>
+    <section>
+        <form autocomplete="off">
+            <!-- Role -->
+            <label for="role">Role: Offering</label>
+            <input type="checkbox" id="role" checked>
+            <br>
+
+            <!-- Message size to be used -->
+            <label for="message-size">Message size (bytes):</label>
+            <input id="message-size" type="number" name="message-size" value="16384" step="16384">
+            <br>
+
+            <!-- WebSocket URL & Start button -->
+            <input type="text" id="ws-url" placeholder="Optional Server URL">
+            <button type="button" id="start" disabled>Start</button>
+            <br><hr>
+
+            <!-- Copy local description from this textarea -->
+            Copy local description:<br>
+            <textarea rows="15" id="local-description" disabled readonly></textarea>
+
+            <!-- Paste remote description into this textarea -->
+            Paste remote description:<br>
+            <textarea rows="15" id="remote-description" disabled></textarea>
+            <br>
+        </form>
+    </section>
+    <aside>
+        <pre id="log"></pre>
+    </aside>
+</main>
+
+<!-- Import dependencies -->
+<script src="https://webrtc.github.io/adapter/adapter-6.1.1.js"></script>
+<script src="signaling.js"></script>
+<script src="peerconnection.js"></script>
+
+<!-- UI code -->
+<script>
+'use strict';
+
+// Get elements
+const roleCheckbox = document.getElementById('role');
+const messageSizeInput = document.getElementById('message-size');
+const localDescriptionTextarea = document.getElementById('local-description');
+const remoteDescriptionTextarea = document.getElementById('remote-description');
+const wsUrlInput = document.getElementById('ws-url');
+const startButton = document.getElementById('start');
+const logPre = document.getElementById('log');
+
+// Load & store persistent values
+if (typeof(Storage) !== 'undefined') {
+    const persistentElements = [
+        ['role', 'checked', (value) => value === 'true'],
+        ['message-size', 'value'],
+        ['ws-url', 'value']
+    ];
+    for (const [id, property, transform] of persistentElements) {
+        let value = localStorage.getItem(id);
+        const element = document.getElementById(id);
+        if (transform !== undefined) {
+            value = transform(value);
+        }
+        if (value !== null) {
+            element[property] = value;
+        }
+        element.addEventListener('change', () => {
+            localStorage.setItem(id, element[property]);
+        });
+    }
+}
+
+// Display console logs in the browser as well
+for (const name of ['debug', 'error', 'info', 'log', 'warn']) {
+    const method = window.console[name];
+    window.console[name] = function() {
+        method.apply(null, arguments);
+        const entry = document.createElement('div');
+        entry.classList.add(name);
+        for (let i = 0; i < arguments.length; ++i) {
+            let item = arguments[i];
+            if (typeof arguments[i] === 'object') {
+                entry.innerHTML += JSON.stringify(item, null, 2) + ' ';
+            } else {
+                entry.innerHTML += item + ' ';
+            }
+        }
+        logPre.prepend(entry);
+    };
+}
+
+// Auto-select all text when clicking local description
+localDescriptionTextarea.addEventListener('click', function() {
+    this.select();
+});
+
+// Bind start button & enable
+startButton.addEventListener('click', () => {
+    roleCheckbox.disabled = true;
+    messageSizeInput.disabled = true;
+    wsUrlInput.disabled = true;
+    startButton.disabled = true;
+    localDescriptionTextarea.disabled = false;
+    start(roleCheckbox.checked);
+});
+startButton.disabled = false;
+
+const start = (offering) => {
+    console.info('Starting with role:', offering ? 'Offering' : 'Answering');
+
+    // Create signaling instance
+    const wsUrl = wsUrlInput.value;
+    let signaling;
+    if (wsUrl === '') {
+        signaling = new CopyPasteSignaling();
+    } else {
+        signaling = new WebSocketSignaling(wsUrl + (offering ? '/1' : '/0'));
+    }
+    signaling.onLocalDescriptionUpdate = (description) => {
+        localDescriptionTextarea.value = JSON.stringify(description);
+
+        // Enable remote description once local description has been set
+        remoteDescriptionTextarea.disabled = false;
+    };
+    signaling.onRemoteDescriptionUpdate = (description) => {
+        remoteDescriptionTextarea.value = JSON.stringify(description);
+    };
+
+    // Create peer connection instance
+    const pc = new WebRTCPeerConnection(signaling, offering);
+    window.pc = pc;
+
+    // Apply remote description when pasting
+    const onRemoteDescriptionTextareaChange = () => {
+        // Remove event listener
+        remoteDescriptionTextarea.oninput = null;
+        remoteDescriptionTextarea.onchange = null;
+
+        // Apply remote description once (needs to include candidates)
+        const description = JSON.parse(remoteDescriptionTextarea.value);
+        signaling.handleRemoteDescription(description, true)
+            .catch((error) => console.error(error));
+
+        // Make read-only
+        remoteDescriptionTextarea.readOnly = true;
+    };
+    remoteDescriptionTextarea.oninput = onRemoteDescriptionTextareaChange;
+    remoteDescriptionTextarea.onchange = onRemoteDescriptionTextareaChange;
+
+    // Enable remote description early (if not offering)
+    if (!offering) {
+        remoteDescriptionTextarea.disabled = false;
+    }
+
+    // Get message size
+    const messageSize = parseInt(messageSizeInput.value);
+    if (isNaN(messageSize)) {
+        throw 'Invalid message size value';
+    }
+
+    // Create data channels
+    const createDataChannelWithName = (
+        name, options = null, createOnOpenWithName = null, createOnOpenOptions = null
+    ) => {
+        const dc = pc.createDataChannel(name, options);
+        const defaultOnOpenHandler = dc.onopen;
+        dc.onopen = (event) => {
+            defaultOnOpenHandler(event);
+            if (createOnOpenWithName !== null) {
+                window.setTimeout(() => {
+                    createDataChannelWithName(createOnOpenWithName, createOnOpenOptions);
+                }, 1000);
+            }
+            if (messageSize > pc.pc.sctp.maxMessageSize) {
+                console.warn(dc._name, 'message size (' + messageSize + ') > maximum message size' +
+                    ' (' + pc.pc.sctp.maxMessageSize + ')');
+            }
+            let data = new Uint8Array(messageSize);
+            console.log(dc._name, 'outgoing message (' + data.byteLength + ' bytes)');
+            try {
+                dc.send(data);
+            } catch (error) {
+                if (error.name === 'TypeError') {
+                    console.error(dc._name, 'message too large to send');
+                } else {
+                    console.error(dc._name, 'Unknown error:', error.name);
+                }
+            }
+        };
+    };
+    createDataChannelWithName('cat-noises', {
+        negotiated: true,
+        id: 0,
+    }, 'dinosaur-noises');
+};
+
+// Introduction
+console.info("Hello! Press 'Start' when you're ready.");
+</script>
+
+</body>
+</html>
diff --git a/htdocs/webrtc/peerconnection.js b/htdocs/webrtc/peerconnection.js
new file mode 100644
index 0000000..9161966
--- /dev/null
+++ b/htdocs/webrtc/peerconnection.js
@@ -0,0 +1,95 @@
+'use strict';
+
+/**
+ * A WebRTC peer connection helper. Tightly coupled with the signaling
+ * class.
+ */
+class WebRTCPeerConnection {
+    constructor(signaling, offering, configuration = null) {
+        // Set default configuration (if none provided)
+        if (configuration === null) {
+            configuration = {
+                iceServers: [{
+                    urls: 'stun:stun.services.mozilla.com',
+                }],
+            };
+        }
+
+        // Create peer connection and bind events
+        const pc = new RTCPeerConnection(configuration);
+        pc._offering = offering; // Meh!
+        signaling.pc = pc;
+        pc.onnegotiationneeded = async () => {
+            console.log('Negotiation needed');
+
+            // Create offer (if required)
+            if (offering) {
+                console.log('Creating offer');
+                const description = await pc.createOffer();
+                await pc.setLocalDescription(description);
+                signaling.handleLocalDescription(description);
+            }
+        };
+        pc.signalingstatechange = () => {
+            console.log('Signaling state:', pc.signalingState);
+        };
+        pc.oniceconnectionstatechange = () => {
+            console.log('ICE connection state:', pc.iceConnectionState);
+        };
+        pc.onicegatheringstatechange = () => {
+            console.log('ICE gathering state:', pc.iceGatheringState);
+        };
+        pc.onconnectionstatechange = () => {
+            console.log('Connection state:', pc.connectionState);
+        };
+        pc.onicecandidate = (event) => {
+            signaling.handleLocalCandidate(event.candidate);
+        };
+        pc.onicecandidateerror = (event) => {
+            console.error('ICE candidate error:', event);
+        };
+        pc.ondatachannel = (event) => {
+            const dc = event.channel;
+            console.log('Incoming data channel:', dc.label);
+
+            // Bind events
+            this.bindDataChannelEvents(dc);
+        };
+
+        // Store configuration & signalling instance
+        this.pc = pc;
+        this.dcs = {};
+    }
+
+    createDataChannel(name, options = null) {
+        const pc = this.pc;
+
+        // Create data channel and bind events
+        const dc = pc.createDataChannel(name, options);
+        this.bindDataChannelEvents(dc);
+
+        // Store data channel and return
+        this.dcs[name] = dc;
+        return dc;
+    }
+
+    bindDataChannelEvents(dc) {
+        dc._name = dc.label; // Meh!
+        dc.onopen = () => {
+            console.log(dc._name, 'open');
+        };
+        dc.onclose = () => {
+            console.log(dc._name, 'closed');
+        };
+        dc.onerror = (event) => {
+            console.log(dc._name, 'error:', event);
+        };
+        dc.onbufferedamountlow = () => {
+            console.log(dc._name, 'buffered amount low:', dc.bufferedAmount);
+        };
+        dc.onmessage = (event) => {
+            const size = event.data.byteLength || event.data.size;
+            console.log(dc._name, 'incoming message (' + size + ' bytes)');
+        };
+    }
+}
diff --git a/htdocs/webrtc/signaling.js b/htdocs/webrtc/signaling.js
new file mode 100644
index 0000000..ff3e3b0
--- /dev/null
+++ b/htdocs/webrtc/signaling.js
@@ -0,0 +1,211 @@
+'use strict';
+
+/**
+ * A copy & paste signalling implementation.
+ *
+ * Tightly coupled with the WebRTC peer connection class.
+ */
+class CopyPasteSignaling {
+    constructor(pc = null) {
+        this._pc = pc;
+        this.pending_inbound_messages = [];
+        this.localIceCandidatesSent = false;
+        this.remoteIceCandidatesReceived = false;
+        this._onLocalDescriptionUpdate = null;
+        this._onRemoteDescriptionUpdate = null;
+    }
+
+    set pc(pc) {
+        this._pc = pc;
+
+        // Process all pending inbound messages
+        for (const message of this.pending_inbound_messages) {
+            this.receiveMessage(message.type, message.value);
+        }
+    }
+
+    set onLocalDescriptionUpdate(callback) {
+        this._onLocalDescriptionUpdate = callback;
+    }
+
+    set onRemoteDescriptionUpdate(callback) {
+        this._onRemoteDescriptionUpdate = callback;
+    }
+
+    handleLocalDescription(description, complete = false) {
+        console.log('Local description:', description);
+
+        // Send local description
+        this.sendMessage('description', description);
+        if (complete) {
+            this.localIceCandidatesSent = true;
+            this.maybeClose();
+            console.info('Local description complete');
+        }
+
+        // Call 'update'
+        if (this._onLocalDescriptionUpdate !== null) {
+            this._onLocalDescriptionUpdate(this._pc.localDescription);
+        }
+    }
+
+    async handleRemoteDescription(description, complete = false) {
+        // Set remote description
+        console.log('Setting remote description');
+        await this._pc.setRemoteDescription(description);
+        console.log('Remote description:', this._pc.remoteDescription);
+        if (complete) {
+            this.remoteIceCandidatesReceived = true;
+            this.maybeClose();
+            console.info('Remote description complete');
+        }
+
+        // Call 'update' (remote description)
+        if (this._onRemoteDescriptionUpdate !== null) {
+            this._onRemoteDescriptionUpdate(this._pc.remoteDescription);
+        }
+
+        // Create answer (if required)
+        if (!this._pc._offering) {
+            console.log(name, 'Creating answer');
+            description = await this._pc.createAnswer();
+
+            // Apply local description
+            await this._pc.setLocalDescription(description);
+            this.handleLocalDescription(description);
+        }
+    }
+
+    handleLocalCandidate(candidate) {
+        console.log('Local ICE candidate:', candidate);
+
+        // Send local candidate
+        this.sendMessage('candidate', candidate);
+
+        // Special handling for last candidate
+        if (candidate === null) {
+            this.localIceCandidatesSent = true;
+            this.maybeClose();
+            console.info('Local description complete');
+        }
+
+        // Call 'update' (local description)
+        if (this._onLocalDescriptionUpdate !== null) {
+            this._onLocalDescriptionUpdate(this._pc.localDescription);
+        }
+    }
+
+    async handleRemoteCandidate(candidate) {
+        console.log('Remote ICE candidate:', candidate);
+        if (candidate !== null) {
+            // Add remote candidate (if any)
+            await this._pc.addIceCandidate(candidate);
+        } else {
+            // Special handling for last candidate
+            this.remoteIceCandidatesReceived = true;
+            this.maybeClose();
+            console.info('Remote description complete');
+        }
+
+        // Call 'update' (remote description)
+        if (this._onRemoteDescriptionUpdate !== null) {
+            this._onRemoteDescriptionUpdate(this._pc.remoteDescription);
+        }
+    }
+
+    sendMessage(type, value) {
+        // Does nothing by default
+    }
+
+    receiveMessage(type, value) {
+        // Hold back messages until peer connection is set
+        if (this._pc === null) {
+            this.pending_inbound_messages.push({type: type, value: value});
+        }
+
+        // Handle message
+        switch (type) {
+            case 'description':
+                this.handleRemoteDescription(value).catch((error) => console.error(error));
+                break;
+            case 'candidate':
+                this.handleRemoteCandidate(value).catch((error) => console.error(error));
+                break;
+            default:
+                console.warn('Unknown message type:', type);
+                break;
+        }
+    }
+
+    maybeClose() {
+        // Close once all messages have been exchanged
+        if (this.localIceCandidatesSent && this.remoteIceCandidatesReceived) {
+            console.log('Closing signalling channel');
+            this.close();
+        }
+    }
+
+    close() {
+        // Does nothing by default
+    }
+}
+
+/**
+ * A signalling implementation intended for this signalling server:
+ * https://github.com/rawrtc/rawrtc-terminal-demo/tree/master/signaling
+ *
+ * Tightly coupled with the WebRTC peer connection class.
+ *
+ * Example: `ws://localhost/meow/0` when offering, and
+ *          `ws://localhost/meow/1` when answering.
+ */
+class WebSocketSignaling extends CopyPasteSignaling {
+    constructor(wsUrl, pc = null) {
+        super(pc);
+        this.pending_outbound_messages = [];
+
+        const ws = new WebSocket(wsUrl);
+        ws.onopen = () => {
+            console.log('WS open');
+            for (const message of this.pending_outbound_messages) {
+                this.sendMessage(message.type, message.value);
+            }
+        };
+        ws.onclose = () => {
+            console.log('WS closed');
+        };
+        ws.onerror = (event) => {
+            console.error('WS error:', event);
+        };
+        ws.onmessage = (event) => {
+            const message = JSON.parse(event.data);
+            if (!('type' in message)) {
+                console.warn("Invalid message, did not contain a 'type' field");
+                return;
+            }
+            this.receiveMessage(message.type, message.value || null);
+        };
+
+        // Store web socket instance
+        this.ws = ws;
+    }
+
+    sendMessage(type, value) {
+        // Cache if not open, yet.
+        if (this.ws.readyState !== 1) {
+            this.pending_outbound_messages.push({type: type, value: value});
+            return;
+        }
+
+        // Send
+        this.ws.send(JSON.stringify({
+            type: type,
+            value: value
+        }));
+    }
+
+    close() {
+        super.close();
+        this.ws.close();
+    }
+}