1 files changed, 250 insertions, 0 deletions
diff --git a/devtools/server/socket/websocket-server.js b/devtools/server/socket/websocket-server.js
new file mode 100644
index 0000000000..4236ec2921
--- /dev/null
+++ b/devtools/server/socket/websocket-server.js
@@ -0,0 +1,250 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const { executeSoon } = require("resource://devtools/shared/DevToolsUtils.js");
+const {
+  delimitedRead,
+} = require("resource://devtools/shared/transport/stream-utils.js");
+const CryptoHash = Components.Constructor(
+  "@mozilla.org/security/hash;1",
+  "nsICryptoHash",
+  "initWithString"
+);
+const threadManager = Cc["@mozilla.org/thread-manager;1"].getService();
+
+// Limit the header size to put an upper bound on allocated memory
+const HEADER_MAX_LEN = 8000;
+
+/**
+ * Read a line from async input stream and return promise that resolves to the line once
+ * it has been read. If the line is longer than HEADER_MAX_LEN, will throw error.
+ */
+function readLine(input) {
+  return new Promise((resolve, reject) => {
+    let line = "";
+    const wait = () => {
+      input.asyncWait(
+        stream => {
+          try {
+            const amountToRead = HEADER_MAX_LEN - line.length;
+            line += delimitedRead(input, "\n", amountToRead);
+
+            if (line.endsWith("\n")) {
+              resolve(line.trimRight());
+              return;
+            }
+
+            if (line.length >= HEADER_MAX_LEN) {
+              throw new Error(
+                `Failed to read HTTP header longer than ${HEADER_MAX_LEN} bytes`
+              );
+            }
+
+            wait();
+          } catch (ex) {
+            reject(ex);
+          }
+        },
+        0,
+        0,
+        threadManager.currentThread
+      );
+    };
+
+    wait();
+  });
+}
+
+/**
+ * Write a string of bytes to async output stream and return promise that resolves once
+ * all data has been written. Doesn't do any utf-16/utf-8 conversion - the string is
+ * treated as an array of bytes.
+ */
+function writeString(output, data) {
+  return new Promise((resolve, reject) => {
+    const wait = () => {
+      if (data.length === 0) {
+        resolve();
+        return;
+      }
+
+      output.asyncWait(
+        stream => {
+          try {
+            const written = output.write(data, data.length);
+            data = data.slice(written);
+            wait();
+          } catch (ex) {
+            reject(ex);
+          }
+        },
+        0,
+        0,
+        threadManager.currentThread
+      );
+    };
+
+    wait();
+  });
+}
+
+/**
+ * Read HTTP request from async input stream.
+ * @return Request line (string) and Map of header names and values.
+ */
+const readHttpRequest = async function (input) {
+  let requestLine = "";
+  const headers = new Map();
+
+  while (true) {
+    const line = await readLine(input);
+    if (!line.length) {
+      break;
+    }
+
+    if (!requestLine) {
+      requestLine = line;
+    } else {
+      const colon = line.indexOf(":");
+      if (colon == -1) {
+        throw new Error(`Malformed HTTP header: ${line}`);
+      }
+
+      const name = line.slice(0, colon).toLowerCase();
+      const value = line.slice(colon + 1).trim();
+      headers.set(name, value);
+    }
+  }
+
+  return { requestLine, headers };
+};
+
+/**
+ * Write HTTP response (array of strings) to async output stream.
+ */
+function writeHttpResponse(output, response) {
+  const responseString = response.join("\r\n") + "\r\n\r\n";
+  return writeString(output, responseString);
+}
+
+/**
+ * Process the WebSocket handshake headers and return the key to be sent in
+ * Sec-WebSocket-Accept response header.
+ */
+function processRequest({ requestLine, headers }) {
+  const [method, path] = requestLine.split(" ");
+  if (method !== "GET") {
+    throw new Error("The handshake request must use GET method");
+  }
+
+  if (path !== "/") {
+    throw new Error("The handshake request has unknown path");
+  }
+
+  const upgrade = headers.get("upgrade");
+  if (!upgrade || upgrade !== "websocket") {
+    throw new Error("The handshake request has incorrect Upgrade header");
+  }
+
+  const connection = headers.get("connection");
+  if (
+    !connection ||
+    !connection
+      .split(",")
+      .map(t => t.trim())
+      .includes("Upgrade")
+  ) {
+    throw new Error("The handshake request has incorrect Connection header");
+  }
+
+  const version = headers.get("sec-websocket-version");
+  if (!version || version !== "13") {
+    throw new Error(
+      "The handshake request must have Sec-WebSocket-Version: 13"
+    );
+  }
+
+  // Compute the accept key
+  const key = headers.get("sec-websocket-key");
+  if (!key) {
+    throw new Error(
+      "The handshake request must have a Sec-WebSocket-Key header"
+    );
+  }
+
+  return { acceptKey: computeKey(key) };
+}
+
+function computeKey(key) {
+  const str = key + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
+
+  const data = Array.from(str, ch => ch.charCodeAt(0));
+  const hash = new CryptoHash("sha1");
+  hash.update(data, data.length);
+  return hash.finish(true);
+}
+
+/**
+ * Perform the server part of a WebSocket opening handshake on an incoming connection.
+ */
+const serverHandshake = async function (input, output) {
+  // Read the request
+  const request = await readHttpRequest(input);
+
+  try {
+    // Check and extract info from the request
+    const { acceptKey } = processRequest(request);
+
+    // Send response headers
+    await writeHttpResponse(output, [
+      "HTTP/1.1 101 Switching Protocols",
+      "Upgrade: websocket",
+      "Connection: Upgrade",
+      `Sec-WebSocket-Accept: ${acceptKey}`,
+    ]);
+  } catch (error) {
+    // Send error response in case of error
+    await writeHttpResponse(output, ["HTTP/1.1 400 Bad Request"]);
+    throw error;
+  }
+};
+
+/**
+ * Accept an incoming WebSocket server connection.
+ * Takes an established nsISocketTransport in the parameters.
+ * Performs the WebSocket handshake and waits for the WebSocket to open.
+ * Returns Promise with a WebSocket ready to send and receive messages.
+ */
+const accept = async function (transport, input, output) {
+  await serverHandshake(input, output);
+
+  const transportProvider = {
+    setListener(upgradeListener) {
+      // The onTransportAvailable callback shouldn't be called synchronously.
+      executeSoon(() => {
+        upgradeListener.onTransportAvailable(transport, input, output);
+      });
+    },
+  };
+
+  return new Promise((resolve, reject) => {
+    const socket = WebSocket.createServerWebSocket(
+      null,
+      [],
+      transportProvider,
+      ""
+    );
+    socket.addEventListener("close", () => {
+      input.close();
+      output.close();
+    });
+
+    socket.onopen = () => resolve(socket);
+    socket.onerror = err => reject(err);
+  });
+};
+
+exports.accept = accept;