net: More accurate IP address validation and IPv6 dotted notation.

* Added isIP method to make use of inet_pton to cares_wrap.cc
* Modified net.isIP() to make use of new C++ isIP method.
* Added new tests to test-net-isip.js.

This is a back-port of commit fb6377e from the master branch.

lib/net.js

@@ -24,6 +24,7 @@ var Stream = require('stream');
 var timers = require('timers');
 var util = require('util');
 var assert = require('assert');
+var cares = process.binding('cares_wrap');
 var cluster;
 
 function noop() {}
@@ -1091,27 +1092,7 @@ Server.prototype._setupSlave = function(socketList) {
 
 // TODO: isIP should be moved to the DNS code. Putting it here now because
 // this is what the legacy system did.
-// NOTE: This does not accept IPv6 with an IPv4 dotted address at the end,
-//  and it does not detect more than one double : in a string.
-exports.isIP = function(input) {
-  if (!input) {
-    return 0;
-  } else if (/^(\d?\d?\d)\.(\d?\d?\d)\.(\d?\d?\d)\.(\d?\d?\d)$/.test(input)) {
-    var parts = input.split('.');
-    for (var i = 0; i < parts.length; i++) {
-      var part = parseInt(parts[i]);
-      if (part < 0 || 255 < part) {
-        return 0;
-      }
-    }
-    return 4;
-  } else if (/^::|^::1|^([a-fA-F0-9]{1,4}::?){1,7}([a-fA-F0-9]{1,4})$/.test(
-      input)) {
-    return 6;
-  } else {
-    return 0;
-  }
-};
+exports.isIP = cares.isIP;
 
 
 exports.isIPv4 = function(input) {

src/cares_wrap.cc

@@ -685,6 +685,24 @@ void AfterGetAddrInfo(uv_getaddrinfo_t* req, int status, struct addrinfo* res) {
 }
 
 
+static Handle<Value> IsIP(const Arguments& args) {
+  HandleScope scope;
+
+  String::AsciiValue ip(args[0]);
+  char address_buffer[sizeof(struct in6_addr)];
+
+  if (uv_inet_pton(AF_INET, *ip, &address_buffer) == 1) {
+    return scope.Close(v8::Integer::New(4));
+  }
+
+  if (uv_inet_pton(AF_INET6, *ip, &address_buffer) == 1) {
+    return scope.Close(v8::Integer::New(6));
+  }
+
+  return scope.Close(v8::Integer::New(0));
+}
+
+
 static Handle<Value> GetAddrInfo(const Arguments& args) {
   HandleScope scope;
 
@@ -750,6 +768,7 @@ static void Initialize(Handle<Object> target) {
   NODE_SET_METHOD(target, "getHostByName", QueryWithFamily<GetHostByNameWrap>);
 
   NODE_SET_METHOD(target, "getaddrinfo", GetAddrInfo);
+  NODE_SET_METHOD(target, "isIP", IsIP);
 
   target->Set(String::NewSymbol("AF_INET"), Integer::New(AF_INET));
   target->Set(String::NewSymbol("AF_INET6"), Integer::New(AF_INET6));

test/simple/test-net-isip.js

@@ -31,7 +31,20 @@ assert.equal(net.isIP('0000:0000:0000:0000:0000:0000:0000:0000::0000'), 0);
 assert.equal(net.isIP('1050:0:0:0:5:600:300c:326b'), 6);
 assert.equal(net.isIP('2001:252:0:1::2008:6'), 6);
 assert.equal(net.isIP('2001:dead:beef:1::2008:6'), 6);
+assert.equal(net.isIP('2001::'), 6);
+assert.equal(net.isIP('2001:dead::'), 6);
+assert.equal(net.isIP('2001:dead:beef::'), 6);
+assert.equal(net.isIP('2001:dead:beef:1::'), 6);
 assert.equal(net.isIP('ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff'), 6);
+assert.equal(net.isIP(':2001:252:0:1::2008:6:'), 0);
+assert.equal(net.isIP(':2001:252:0:1::2008:6'), 0);
+assert.equal(net.isIP('2001:252:0:1::2008:6:'), 0);
+assert.equal(net.isIP('2001:252::1::2008:6'), 0);
+assert.equal(net.isIP('::2001:252:1:2008:6'), 6);
+assert.equal(net.isIP('::2001:252:1:1.1.1.1'), 6);
+assert.equal(net.isIP('::2001:252:1:255.255.255.255'), 6);
+assert.equal(net.isIP('::2001:252:1:255.255.255.255.76'), 0);
+assert.equal(net.isIP('::anything'), 0);
 assert.equal(net.isIP('::1'), 6);
 assert.equal(net.isIP('::'), 6);
 assert.equal(net.isIP('0000:0000:0000:0000:0000:0000:12345:0000'), 0);
@@ -45,4 +58,4 @@ assert.equal(net.isIPv4('2001:252:0:1::2008:6'), false);
 
 assert.equal(net.isIPv6('127.0.0.1'), false);
 assert.equal(net.isIPv6('example.com'), false);
-assert.equal(net.isIPv6('2001:252:0:1::2008:6'), true);
+assert.equal(net.isIPv6('2001:252:0:1::2008:6'), true);