Convert the type code to a string. Throw for unknown codes since we m…

…ay not parse others correctly.
wanderview · Feb 17, 2013 · 977b7d9 · 977b7d9
1 parent 7abb7b9
commit 977b7d9
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Showing 4 changed files with 39 additions and 11 deletions.
diff --git a/README.md b/README.md
@@ -16,7 +16,7 @@ var EtherFrame = require('ether-frame');
 var ef = EtherFrame.fromBuffer(buf);
 ef.src === '12:34:56:78';           // true
 ef.dst === '98:76:54:32':           // true
-ef.type === EtherFrame.TYPE_IP;     // true
+ef.type === 'ip';                   // true
 ef.bytes === 14;                    // true
 var payload = buf.slice(ef.bytes);
 var buf = ef.toBuffer();

diff --git a/ether.js b/ether.js
@@ -27,8 +27,15 @@ module.exports = EtherFrame;
 
 var mac = require('mac-address');
 
-EtherFrame.TYPE_IP = 0x0800;
-EtherFrame.TYPE_ARP = 0x0806;
+var TYPE_TO_STRING = {
+  0x0800: 'ip',
+  0x0806: 'arp'
+};
+
+var TYPE_FROM_STRING = {
+  ip: 0x0800,
+  arp: 0x0806
+};
 
 function EtherFrame(opts) {
   if (opts instanceof Buffer) {
@@ -41,9 +48,9 @@ function EtherFrame(opts) {
 
   opts = opts || {};
 
-  self.src = opts.src || '00:00:00:00:00:00';
-  self.dst = opts.dst || '00:00:00:00:00:00';
-  self.type = opts.type || EtherFrame.TYPE_IP;
+  self.src = opts.src || mac.ZERO;
+  self.dst = opts.dst || mac.ZERO;
+  self.type = opts.type || 'ip';
   self.bytes = opts.bytes || ((mac.LENGTH * 2) + 2);
 
   return self;
@@ -59,9 +66,14 @@ EtherFrame.fromBuffer = function(buf, offset) {
   var src = mac.toString(buf, offset + bytes);
   bytes += mac.LENGTH;
 
-  var type = buf.readUInt16BE(offset + bytes);
+  var typeCode = buf.readUInt16BE(offset + bytes);
   bytes += 2;
 
+  var type = TYPE_TO_STRING[typeCode];
+  if (!type) {
+    throw(new Error('Unsupported type code [' + typeCode + ']'));
+  }
+
   return new EtherFrame({ dst: dst, src: src, type: type, bytes: bytes });
 };
 
@@ -75,7 +87,12 @@ EtherFrame.prototype.toBuffer = function(buf, offset) {
   mac.toBuffer(this.src, buf, offset);
   offset += mac.LENGTH;
 
-  buf.writeUInt16BE(this.type, offset);
+  var typeCode = TYPE_FROM_STRING[this.type];
+  if (typeof typeCode !== 'number') {
+    throw(new Error('Unsupported type [' + this.type + ']'));
+  }
+
+  buf.writeUInt16BE(typeCode, offset);
   offset += 2;
 
   return buf;

diff --git a/package.json b/package.json
@@ -12,7 +12,7 @@
   "author": "Ben Kelly <ben@wanderview.com>",
   "license": "BSD",
   "dependencies": {
-    "mac-address": "~0.2.0"
+    "mac-address": "~0.3.0"
   },
   "devDependencies": {
     "nodeunit": "~0.7.4",

diff --git a/test/test-ether.js b/test/test-ether.js
@@ -39,7 +39,7 @@ module.exports.fromBuffer = function(test) {
     var ether = EtherFrame.fromBuffer(payload);
     test.equal('00:50:56:e6:2d:02', ether.dst);
     test.equal('00:0c:29:0d:06:56', ether.src);
-    test.equal(EtherFrame.TYPE_IP, ether.type);
+    test.equal('ip', ether.type);
     test.done();
   });
 };
@@ -53,7 +53,7 @@ module.exports.fromBufferNew = function(test) {
     var ether = new EtherFrame(payload);
     test.equal('00:50:56:e6:2d:02', ether.dst);
     test.equal('00:0c:29:0d:06:56', ether.src);
-    test.equal(EtherFrame.TYPE_IP, ether.type);
+    test.equal('ip', ether.type);
     test.done();
   });
 };
@@ -72,3 +72,14 @@ module.exports.toBuffer = function(test) {
     test.done();
   });
 };
+
+module.exports.defaults = function(test) {
+  test.expect(3);
+
+  var ether = new EtherFrame();
+  test.equal('00:00:00:00:00:00', ether.dst);
+  test.equal('00:00:00:00:00:00', ether.src);
+  test.equal('ip', ether.type);
+
+  test.done();
+};