TCP连接使用socket返回false结果 [英] TCP connect by using socket return false results

问题描述

这是我用来扫描端口是否打开的代码.

Here is the codes which i'm using to scan the port if it's open or not.

https://stackoverflow.com/a/8957053/2203703

有人可以尝试修复它吗?似乎工作不正常，即使端口关闭，代码也总是返回成功连接"

Could anyone try to fix it please? it seems not work correctly, even if the port is off, the codes always return "successfully connected"

这是我用 80 端口测试过的 ip 列表

Here is the ip list which i have tested it with port 80

79.142.126.3 //Connection refused 
222.165.195.103 //Connection refused
64.75.193.162 //Connection refused
118.97.197.146 //Port is open
222.134.154.103 //Connection timed out 
173.0.59.170 //Port is open

这是输出:

5 sockets connected successfully
79.142.126.3 connected successfully
222.165.195.103 connected successfully
64.75.193.162 connected successfully
118.97.197.146 connected successfully
173.0.59.170 connected successfully

代码看起来不错，但我真的找不到问题.

Codes looks fine, but i really can't find the problem.

有什么帮助吗?

推荐答案

您链接的代码是很久以前写的，当时我对非阻塞 I/O 的许多方面的了解有限.

The code you link was written a long time ago, when I had a limited understanding of many aspects of non-blocking I/O.

这确实需要一个事件循环，其中有很多实现，但对于这个例子，我将使用 @rdlowrey 的 Alert 库，因为它是一个极简的代码，应该很容易理解.您还可以在 React 中进行循环，它的级别更高并提供更多功能.

Really this needs an event loop, of which there are many implementations, but for this example I'll use @rdlowrey's Alert library, because it is a minimalist code that should be fairly easy to understand. You can also take a loop at React, which is higher level and provides many more features.

注意下面的例子需要 PHP 5.4+

Note that the below example requires PHP 5.4+

<?php

// Array of addresses to test
$addresses = [
    '192.168.5.150',
    '192.168.5.152',
    'google.com',    // Important note: DNS is resolved synchronously here.
    '192.168.5.155', // this can seriously slow down the process as it can block
    '192.168.5.20',  // for a few seconds, async DNS resolution is non-trivial
    '192.168.40.40', // though
];
// The TCP port to test
$port = 80;
// The length of time in seconds to allow host to respond
$timeout = 5;

// This will hold the results
$lookups = [];

// Create a reactor
$reactor = (new \Alert\ReactorFactory)->select();

$count = count($addresses);
$completedCount = 0;

$onComplete = function($address, $result)
                  use(&$lookups, &$completedCount, $count, $reactor) {

    // Cancel the watchers for this address
    $reactor->cancel($lookups[$address]['failWatcher']);
    $reactor->cancel($lookups[$address]['writeWatcher']);
    $reactor->cancel($lookups[$address]['readWatcher']);

    // Store the result
    $lookups[$address] = $result;

    // If there's nothing left to do, stop the reactor
    if (++$completedCount == $count) {
        $reactor->stop();
    }
};

foreach ($addresses as $address) {
    // Normalise the address to lower-case, as it will be used as an array key
    $address = strtolower($address);

    if (!isset($lookups[$address])) {
        // Create a socket to connect asynchronously
        $sockAddr = "tcp://{$address}:{$port}";
        $flags = STREAM_CLIENT_ASYNC_CONNECT;
        $socket = stream_socket_client($sockAddr, $errNo, $errStr, 0, $flags);
        stream_set_blocking($socket, 0);

        // Set up a timeout to watch for failed connections
        $failWatcher = function() use($address, $onComplete, $timeout) {
            echo "{$address} connect failed: Connect timed out\n";
            $onComplete($address, false);
        };
        $failWatcherId = $reactor->once($failWatcher, $timeout);

        // Watch for the stream becoming writable (connection success)
        $writeWatcher = function() use($address, $onComplete) {
            echo "{$address} connected successfully\n";
            $onComplete($address, true);
        };
        $writeWatcherId = $reactor->onWritable($socket, $writeWatcher);

        // Watch for the stream becoming readable (success or explicit fail)
        $readWatcher = function() use($address, $onComplete, $socket) {
            if ('' === $data = fread($socket, 1024)) {
                echo "{$address} connect failed: Server refused connection\n";
                $onComplete($address, false);
            } else if ($data === false) {
                echo "{$address} connect failed: Stream read error\n";
                $onComplete($address, false);
            } else {
                echo "{$address} connected successfully\n";
                $onComplete($address, true);
            }
        };
        $readWatcherId = $reactor->onReadable($socket, $readWatcher);

        // Store the watcher IDs so they can be destroyed later
        $lookups[$address] = [
            'failWatcher'  => $failWatcherId,
            'writeWatcher' => $writeWatcherId,
            'readWatcher'  => $readWatcherId,
        ];
    }
}

// Set everything going
$reactor->run();

// $lookups is now an array of booleans indicating whether the address resulted
// in a successful connection

这篇关于TCP连接使用socket返回false结果的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！