From fa9113e36a63119dbe9527dd05b3c18ea542942a Mon Sep 17 00:00:00 2001
From: anD <andrey_irc@ukr.net>
Date: Thu, 16 Jan 2020 01:51:37 +0200
Subject: [PATCH] [task_networks]: search for opened ports on host

---
 submissions/anD/port-sniffer/sniffer.js | 155 ++++++++++++++++++++++++
 1 file changed, 155 insertions(+)
 create mode 100644 submissions/anD/port-sniffer/sniffer.js

diff --git a/submissions/anD/port-sniffer/sniffer.js b/submissions/anD/port-sniffer/sniffer.js
new file mode 100644
index 0000000..80081ef
--- /dev/null
+++ b/submissions/anD/port-sniffer/sniffer.js
@@ -0,0 +1,155 @@
+const net = require('net');
+const dns = require('dns').promises;
+
+function help () {
+  return ` Sniffer is CLI tool which allows user to search for opened TCP ports on host 
+          Synopsis:
+              node sniffer.js [options] [value]
+              
+           Examples:
+              node sniffer.js --ports 10-9999 --host google.com
+              node sniffer.js --host google.com --ports 172.213.3.110
+              node sniffer.js --host google.com --ports 10 --timeout 3000
+          
+           Options:
+              --ports            sets value from port range 1-65535 
+              --host             sets hostname or IP address(172.213.3.110, google.com)
+              --timeout          sets timeout milliseconds of inactivity on the socket.By default 300 ms 
+              --help            print usage message on console
+          `;
+}
+
+function getArguments (...requiredFlags) {
+  const args = process.argv.slice(2);
+
+  return args.reduce((args, argvFlag, argvIndex, argvArray) => {
+    this.arguments = args;
+
+    requiredFlags.forEach(flag => {
+      if (
+        argvFlag === flag &&
+        argvIndex % 2 === 0 &&
+        argvArray.length % 2 === 0
+      ) {
+        this.arguments[argvFlag.replace('--', '')] = argvArray[argvIndex + 1];
+      } else if (argvArray.length === 1 && argvFlag === flag) {
+        this.arguments[argvFlag.replace('--', '')] = true;
+      }
+    });
+
+    if (Object.keys(this.arguments).length === 0) {
+      process.stdout.write(`The required arguments are: ${requiredFlags}\n`);
+      process.exit(1);
+    }
+    return this.arguments;
+  }, {});
+}
+
+function getPort (ports) {
+  const defaultRange = '1-65535';
+  if (!ports) {
+    ports = defaultRange;
+  }
+  return ports
+    .toString()
+    .split('-')
+    .map((item, index, arr) => {
+      if (isNaN(Number(item)) || arr[index] >= arr[index + 1]) {
+        process.stdout.write(
+          "--ports value isn't a number or have incorrect format\n"
+        );
+        process.exit(1);
+      }
+      return Number(item);
+    });
+}
+
+function connect (port, host, timeout) {
+  return new Promise((resolve, reject) => {
+    const socket = new net.Socket();
+
+    socket.setTimeout(Number(timeout) || 300);
+
+    socket.on('connect', () => {
+      process.stdout.write('.');
+      resolve(port);
+      socket.destroy();
+    });
+
+    socket.on('timeout', () => {
+      const err = new Error(`timeout: ${port} `);
+      reject(err.message);
+      socket.destroy();
+    });
+
+    socket.on('lookup', err => {
+      if (err) {
+        socket.destroy();
+        reject(err);
+      }
+    });
+
+    socket.on('error', err => {
+      reject(err);
+      socket.destroy();
+    });
+
+    socket.connect(port, host);
+  });
+}
+
+function handleError (e) {
+  if (e.code === 'ENOENT' || e.code === 'ENOTFOUND') {
+    throw e.message;
+  } else if (e.code === 'ERR_SOCKET_BAD_PORT') {
+    const err = 'Port should be >= 0 and < 65536';
+    throw (err.message);
+  }
+
+  return e;
+}
+
+function getHostIp (host) {
+  return dns
+    .lookup(host)
+    .then(ip => ip.address)
+    .catch(e => handleError(e));
+}
+
+async function getConnectionResponse (host, [start, end], timeout) {
+  this.end = end || start;
+  const response = [];
+  const ip = await getHostIp(host);
+
+  for (let port = start; port <= this.end; port += 1) {
+    response.push(connect(port, ip, timeout).catch(e => handleError(e)));
+  }
+
+  const promise = await Promise.all(response);
+  return promise;
+}
+
+(function scan () {
+  const args = getArguments('--ports', '--host', '--timeout', '--help');
+
+  const range = getPort(args.ports);
+
+  if (args.help) {
+    process.stdout.write(`${help()}\n`);
+    process.exit(0);
+  }
+
+  getConnectionResponse(args.host, range, args.timeout).then(
+    resolved => {
+      const openPorts = resolved.filter(Number);
+      openPorts.length > 0
+        ? process.stdout.write(`\n${openPorts} ports are opened\n`)
+        : process.stdout.write('no opened ports\n');
+    },
+
+    rejected => {
+      process.stdout.write(`${rejected}\n`);
+      process.exit(1);
+    }
+  );
+})();