文章摘要
这篇文章是一段使用 Perl 语言实现的 SOCKS4 代理服务器代码。代码中定义了多个函数，包括初始化连接、读取写入数据、用户认证、以及网络连接和绑定的实现。文章的核心内容是通过 Perl 编程语言构建一个简单的 SOCKS4 代理服务器，支持用户认证和简单的网络数据传输。代码中涉及的主要功能包括读取客户端数据、处理用户认证请求、解密数据、以及通过 TCP 协议进行连接和绑定操作。
#!/usr/bin/perl
$auth_enabled=0;
$auth_login=”hidden”;
$auth_pass=”hidden”;
$port=44269;
use IO::Socket::INET;
$SIG{‘CHLD’}=’IGNORE’;
$bind=IO::Socket::INET->new(Listen=>10, Reuse=>1, LocalPort=>$port) or die “Нельзя забиндить порт $port\n”;
while($client=$bind->accept()) {
$client->autoflush();
if(fork()){ $client->close(); }
else { $bind->close(); new_client($client); exit(); }
}
sub new_client {
local $t, $i, $buff, $ord, $success;
local $client=$_[0];
sysread($client, $buff, 1);
if(ord($buff)==5) {
sysread($client, $buff, 1);
$t=ord($buff);
unless(sysread($client, $buff, $t)==$t) { return; }
$success=0;
for($i=0; $i < $t; $i++) {
$ord=ord(substr($buff, $i, 1));
if($ord==0 && !$auth_enabled) {
syswrite($client, “\x05\x00″, 2);
$success++;
break;
}
elsif($ord==2 && $auth_enabled) {
unless(do_auth($client)){ return; }
$success++;
break;
}
}
if($success) {
$t=sysread($client, $buff, 3);
if(substr($buff, 0, 1)==’\x05′) {
if(ord(substr($buff, 2, 1))==0) {
($host, $raw_host)=socks_get_host($client);
if(!$host) { return; }
($port, $raw_port)=socks_get_port($client);
if(!$port) { return; }
$ord=ord(substr($buff, 1, 1));
$buff=”\x05\x00\x00”.$raw_host.$raw_port;
syswrite($client, $buff, length($buff));
socks_do($ord, $client, $host, $port);
}
}
} else { syswrite($client, “\x05\xFF”, 2); };
}
$client->close();
}
sub do_auth {
local $buff, $login, $pass;
local $client=$_[0];
syswrite($client, “\x05\x02”, 2);
sysread($client, $buff, 1);
if(ord($buff)==1) {
sysread($client, $buff, 1);
sysread($client, $login, ord($buff));
sysread($client, $buff, 1);
sysread($client, $pass, ord($buff));
if($login eq $auth_login && $pass eq $auth_pass) {
syswrite($client, “\x05\x00”, 2);
return 1;
} else { syswrite($client, “\x05\x01″, 2); }
}
$client->close();
return 0;
}
sub socks_get_host {
local $client=$_[0];
local $t, $ord, $raw_host;
local $host=””;
sysread($client, $t, 1);
$ord=ord($t);
if($ord==1) {
sysread($client, $raw_host, 4);
@host=$raw_host=~ /(.)/g;
$host=ord($host[0]).”.”.ord($host[1]).”.”.ord($host[2]).”.”.ord($host[3]);
} elsif($ord==3) {
sysread($client, $raw_host, 1);
sysread($client, $host, ord($raw_host));
$raw_host .=$host;
} elsif($ord==4) {
#ipv6 – not supported
}
return ($host, $t.$raw_host);
}
sub socks_get_port {
local $client=$_[0];
local $raw_port, $port;
sysread($client, $raw_port, 2);
$port=ord(substr($raw_port, 0, 1)) << 8 | ord(substr($raw_port, 1, 1));
return ($port, $raw_port);
}
sub socks_do {
local($t, $client, $host, $port)=@_;
if($t==1) { socks_connect($client, $host, $port); }
elsif($t==2) { socks_bind($client, $host, $port); }
elsif($t==3) { socks_udp_associate($client, $host, $port); }
else { return 0; }
return 1;
}
sub socks_connect {
my($client, $host, $port)=@_;
my $target=IO::Socket::INET->new(PeerAddr=> $host, PeerPort=> $port, Proto=> ‘tcp’, Type=> SOCK_STREAM);
unless($target) { return; }
$target->autoflush();
while($client || $target) {
my $rin=””;
vec($rin, fileno($client), 1)=1 if $client;
vec($rin, fileno($target), 1)=1 if $target;
my($rout, $eout);
select($rout=$rin, undef, $eout=$rin, 120);
if (!$rout && !$eout) { return; }
my $cbuffer=””;
my $tbuffer=””;
if ($client && (vec($eout, fileno($client), 1) || vec($rout, fileno($client), 1))) {
my $result=sysread($client, $tbuffer, 1024);
if (!defined($result) || !$result) { return; }
}
if ($target && (vec($eout, fileno($target), 1) || vec($rout, fileno($target), 1))) {
my $result=sysread($target, $cbuffer, 1024);
if (!defined($result) || !$result) { return; }
}
if ($fh && $tbuffer) { print $fh $tbuffer; }
while (my $len=length($tbuffer)) {
my $res=syswrite($target, $tbuffer, $len);
if ($res > 0) { $tbuffer=substr($tbuffer, $res); } else { return; }
}
while (my $len=length($cbuffer)) {
my $res=syswrite($client, $cbuffer, $len);
if ($res > 0) { $cbuffer=substr($cbuffer, $res); } else { return; }
}
}
}
sub socks_bind {
my($client, $host, $port)=@_;
}
sub socks_udp_associate {
my($client, $host, $port)=@_;
}