Move connection to self detection to transport

README.md

@@ -107,7 +107,6 @@ var messages = require("bitmessage").messages;
 
 // Simple encoding and decoding:
 var vermsg = messages.version.encode({
-  nonce: Buffer(8),  // Hack detection connection to self
   remoteHost: "1.1.1.1",
   remotePort: 8444,
 });

lib/messages.js

@@ -10,7 +10,6 @@
  *
  * // Simple encoding and decoding:
  * var vermsg = messages.version.encode({
- *   nonce: Buffer(8),  // Hack detection connection to self
  *   remoteHost: "1.1.1.1",
  *   remotePort: 8444,
  * });
@@ -35,7 +34,6 @@
 "use strict";
 
 var objectAssign = Object.assign || require("object-assign");
-var bufferEqual = require("buffer-equal");
 var assert = require("./_util").assert;
 var structs = require("./structs");
 var bmcrypto = require("./crypto");
@@ -69,9 +67,6 @@ exports.getCommand = function(buf) {
   return command.slice(0, firstNonNull).toString("ascii");
 };
 
-// Random nonce used to detect connections to self.
-var randomNonce = bmcrypto.randomBytes(8);
-
 /**
  * `version` message.
  * @see {@link https://bitmessage.org/wiki/Protocol_specification#version}
@@ -97,8 +92,8 @@ var version = exports.version = {
    * message
    * @property {number} port - Incoming port of the node sending this
    * message
-   * @property {Buffer} nonce - Random nonce used to detect connection
-   * to self
+   * @property {Buffer} nonce - An 8-byte random nonce used to detect
+   * connection to self
    * @property {string} userAgent - [User agent]{@link
    * module:bitmessage/user-agent} of the node
    * @property {number[]} streams - Streams accepted by the node
@@ -106,6 +101,12 @@ var version = exports.version = {
    * @memberof module:bitmessage/messages.version
    */
 
+  /**
+   * Random nonce used to detect connections to self.
+   * @constant {Buffer}
+   */
+  randomNonce: bmcrypto.randomBytes(8),
+
   /**
    * Decode `version` message.  
    * NOTE: `nonce` is copied.
@@ -134,7 +135,6 @@ var version = exports.version = {
     var addrFrom = structs.net_addr.decode(buf.slice(46, 72), short);
     var nonce = new Buffer(8);
     buf.copy(nonce, 0, 72, 80);
-    assert(!bufferEqual(nonce, randomNonce), "Connection to self");
     var decodedUa = UserAgent.decode(buf.slice(80));
     var decodedStreams = structs.var_int_list.decode(decodedUa.rest);
     return {
@@ -169,8 +169,8 @@ var version = exports.version = {
    * message
    * @param {number=} opts.port - Incoming port of the node (8444 by
    * default)
-   * @param {Buffer=} opts.nonce - Random nonce used to detect connection
-   * to self (unique per node.js process by default)
+   * @param {Buffer=} opts.nonce - An 8-byte random nonce used to detect
+   * connection to self (unique per node.js process by default)
    * @param {(Array|string|Buffer)=} opts.userAgent -
    * [User agent]{@link module:bitmessage/user-agent} of the node
    * (user agent of bitmessage library by default)
@@ -192,7 +192,7 @@ var version = exports.version = {
     var services = opts.services ||
                    ServicesBitfield().set(ServicesBitfield.NODE_NETWORK);
     var time = opts.time || new Date();
-    var nonce = opts.nonce || randomNonce;
+    var nonce = opts.nonce || version.randomNonce;
     assert(nonce.length === 8, "Bad nonce");
     var port = opts.port || 8444;
     var userAgent = opts.userAgent || UserAgent.SELF;

lib/net/base.js

@@ -12,6 +12,7 @@
 
 var inherits = require("inherits");
 var EventEmitter = require("events").EventEmitter;
+var bufferEqual = require("buffer-equal");
 var util = require("../_util");
 var PPromise = require("../platform").Promise;
 var structs = require("../structs");
@@ -157,6 +158,9 @@ BaseTransport.prototype._decodeVersion = function(payload, opts) {
   if (delta < -3600) {
     throw new Error("Peer's time is too far in the past: " + delta + "s");
   }
+  if (bufferEqual(version.nonce, messages.version.randomNonce)) {
+    throw new Error("Connection to self");
+  }
   if (!intersects(this.streams, version.streams)) {
     throw new Error(
       "Peer isn't interested in our streams; " +

tests/unit.js

@@ -514,18 +514,9 @@ describe("Message types", function() {
         remotePort: 48444,
         port: 8444,
         userAgent: "/test:0.0.1/",
-        nonce: Buffer(8),
       }));
       expect(res.userAgent).to.equal("/test:0.0.1/");
     });
-
-    it("should fail on connection to self", function() {
-      expect(version.decode.bind(null, version.encode({
-        remoteHost: "1.2.3.4",
-        remotePort: 48444,
-        port: 8444,
-      }))).to.throw(/connection to self/i);
-    });
   });
 
   describe("addr", function() {