Added missing file

modules/util-dns.js

@@ -0,0 +1,122 @@
+/*
+Copyright 2021 Intel Corporation
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+function windows_dns()
+{
+    var ret = [];
+    var ip = require('_GenericMarshal').CreateNativeProxy('Iphlpapi.dll');
+    ip.CreateMethod('GetNetworkParams');
+
+    var data = require('_GenericMarshal').CreateVariable(1024);
+    var len = require('_GenericMarshal').CreateVariable(4);
+    len.toBuffer().writeUInt32LE(1024);
+
+    if (ip.GetNetworkParams(data, len).Val == 0)
+    {
+        var dnsList = data.Deref(require('_GenericMarshal').PointerSize == 8 ? 272 : 268, 48);
+
+        do
+        {
+            ret.push(dnsList.Deref(require('_GenericMarshal').PointerSize, 16).toBuffer().toString());
+        } while ((dnsList = dnsList.Deref(0, require('_GenericMarshal').PointerSize).Deref().Deref(0, 48)).Val != 0);
+    }
+    return (ret);
+}
+function linux_dns()
+{
+    var child = require('child_process').execFile('/bin/sh', ['sh']);
+    child.stdout.str = ''; child.stdout.on('data', function (c) { this.str += c.toString(); });
+    child.stderr.on('data', function () { });
+    child.stdin.write("cat /etc/resolv.conf | grep nameserver | tr '\n' '`' | awk -F'`' '");
+    child.stdin.write('{');
+    child.stdin.write('   DEL="";');
+    child.stdin.write('   printf "[";');
+    child.stdin.write('   for(i=1;i<NF;++i)');
+    child.stdin.write('   {');
+    child.stdin.write('      if($i~/^#/) { continue; }')
+    child.stdin.write('      z=split($i,T," ");');
+    child.stdin.write('      if(z==2 && T[1]=="nameserver")');
+    child.stdin.write('      {');
+    child.stdin.write('         printf "%s\\\"%s\\\"",DEL,T[2];');
+    child.stdin.write('         DEL=",";');
+    child.stdin.write('      }');
+    child.stdin.write('   }');
+    child.stdin.write('   printf "]";');
+    child.stdin.write("}'");
+    child.stdin.write('\nexit\n');
+    child.waitExit();
+    try
+    {
+        return(JSON.parse(child.stdout.str.trim()));
+    }
+    catch(e)
+    {
+        return ([]);
+    }
+}
+
+function macos_dns()
+{
+    var child = require('child_process').execFile('/bin/sh', ['sh']);
+    child.stdout.str = ''; child.stdout.on('data', function (c) { this.str += c.toString(); });
+    child.stderr.on('data', function () { });
+
+    child.stdin.write("scutil --dns | grep nameserver | tr '\\n' '`' | awk -F'`' '");
+    child.stdin.write('{');
+    child.stdin.write('   DEL="";');
+    child.stdin.write('   printf "{";');
+    child.stdin.write('   for(i=1;i<NF;++i)');
+    child.stdin.write('   {');
+    child.stdin.write('      if($i ~ /^\\s* *\\t*nameserver\\[[0-9]]/)');
+    child.stdin.write('      {');
+    child.stdin.write('         A=split($i,TOK," ");');
+    child.stdin.write('         printf "%s\\"%s\\": \\"%s\\"", DEL, TOK[3], TOK[1];');
+    child.stdin.write('         DEL=",";');
+    child.stdin.write('      }');
+    child.stdin.write('   }');
+    child.stdin.write('   printf "}";');
+    child.stdin.write("}'");
+
+    child.stdin.write('\nexit\n');
+    child.waitExit();
+
+    try
+    {
+        var table = JSON.parse(child.stdout.str.trim());
+        return(table.keys());
+    }
+    catch(e)
+    {
+        return ([]);
+    }
+}
+
+switch (process.platform)
+{
+    case 'linux':
+    case 'freebsd':
+        module.exports = linux_dns;
+        break;
+    case 'win32':
+        module.exports = windows_dns;
+        break;
+    case 'darwin':
+        module.exports = macos_dns;
+        break;
+    default:
+        module.exports = function () { return ([]); };
+        break;
+}