Start voice receive rewrite

src/client/voice/receiver/PacketHandler.js

@@ -0,0 +1,44 @@
+const nonce = Buffer.alloc(24);
+
+class PacketHandler {
+  constructor(receiver) {
+    this.receiver = receiver;
+  }
+
+  parseBuffer(buffer) {
+    // reuse nonce
+    buffer.copy(nonce, 0, 0, 12);
+
+    let packet = secretbox.methods.open(buffer.slice(12), nonce, this.receiver.connection.authentication.secretKey);
+    if (!packet) return Error('Failed to decrypt voice packet');
+    packet = Buffer.from(packet);
+  
+    // Strip RTP Header Extensions (one-byte only)
+    if (packet[0] === 0xBE && packet[1] === 0xDE && packet.length > 4) {
+      const headerExtensionLength = packet.readUInt16BE(2);
+      let offset = 4;
+      for (let i = 0; i < headerExtensionLength; i++) {
+        const byte = packet[offset];
+        offset++;
+        if (byte === 0) continue;
+        offset += 1 + (0b1111 & (byte >> 4));
+      }
+      while (packet[offset] === 0) offset++;
+      packet = packet.slice(offset);
+    }
+
+    return packet;
+  }
+
+  userFromSSRC(ssrc) { return this.receiver.connection.ssrcMap.get(ssrc); }
+
+  push(buffer) {
+    const ssrc = buffer.readUInt32BE(8);
+    const user = this.userFromSSRC(ssrc);
+    if (!user) return;
+    const opusPacket = this.parseBuffer(buffer);
+    if (opusPacket instanceof Error) return;
+  }
+}
+
+module.exports = PacketHandler;