SYNOPSIS
Client
use IO::Socket::Socks;
my $socks_client = IO::Socket::Socks->new(
ProxyAddr => "proxy host",
ProxyPort => "proxy port",
ConnectAddr => "remote host",
ConnectPort => "remote port",
) or die $SOCKS_ERROR;
print $socks_client "foo\n";
$socks_client->close();
Server
use IO::Socket::Socks ':constants';
my $socks_server = IO::Socket::Socks->new(
ProxyAddr => "localhost",
ProxyPort => 8000,
Listen => 1,
UserAuth => \&auth,
RequireAuth => 1
) or die $SOCKS_ERROR;
while(1) {
my $client = $socks_server->accept();
unless ($client) {
print "ERROR: $SOCKS_ERROR\n";
next;
}
my $command = $client->command();
if ($command->[0] == CMD_CONNECT) {
# Handle the CONNECT
$client->command_reply(REPLY_SUCCESS, addr, port);
}
...
#read from the client and send to the CONNECT address
...
$client->close();
}
sub auth {
my ($user, $pass) = @_;
return 1 if $user eq "foo" && $pass eq "bar";
return 0;
}
DESCRIPTION
"IO::Socket::Socks" connects to a SOCKS proxy, tells it to open a connection to a remote host/port when the object is created. The object you receive can be used directly as a socket (with "IO::Socket" interface) for sending and receiving data from the remote host. In addition to create socks client this module could be used to create socks server. See examples below.EXAMPLES
For complete examples of socks 4/5 client and server see `examples' subdirectory in the distribution.METHODS
Socks Client
new( %cfg )new_from_socket($socket, %cfg)
new_from_fd($socket, %cfg)
Creates a new IO::Socket::Socks client object. new_from_socket() is the same as new(), but allows one to create object from an existing and not connected socket (new_from_fd is new_from_socket alias). To make IO::Socket::Socks object from connected socket see "start_SOCKS"
Both takes the following config hash:
SocksVersion => 4 or 5. Default is 5
Timeout => connect/accept timeout
Blocking => Since IO::Socket::Socks version 0.5 you can perform non-blocking connect/bind by
passing false value for this option. Default is true - blocking. See ready()
below for more details.
SocksResolve => resolve host name to ip by proxy server or
not (will resolve by client). This
overrides value of $SOCKS4_RESOLVE or $SOCKS5_RESOLVE
variable. Boolean.
SocksDebug => This will cause all of the SOCKS traffic to
be presented on the command line in a form
similar to the tables in the RFCs. This overrides value
of $SOCKS_DEBUG variable. Boolean.
ProxyAddr => Hostname of the proxy
ProxyPort => Port of the proxy
ConnectAddr => Hostname of the remote machine
ConnectPort => Port of the remote machine
BindAddr => Hostname of the remote machine which will
connect to the proxy server after bind request
BindPort => Port of the remote machine which will
connect to the proxy server after bind request
UdpAddr => Associate UDP socket on the server with this client
hostname
UdpPort => Associate UDP socket on the server with this client
port
AuthType => What kind of authentication to support:
none - no authentication (default)
userpass - Username/Password. For socks5
proxy only.
RequireAuth => Do not send ANON as a valid auth mechanism.
For socks5 proxy only
Username => For socks5 if AuthType is set to userpass, then
you must provide a username. For socks4 proxy with
this option you can specify userid.
Password => If AuthType is set to userpass, then you must
provide a password. For socks5 proxy only.
The following options should be specified:
(ProxyAddr and ProxyPort) (ConnectAddr and ConnectPort) or (BindAddr and BindPort) or (UdpAddr and UdpPort)
Other options are facultative.
start_SOCKS($socket, %cfg)
This is a class method to start socks handshake on already connected socket. This will bless passed $socket to IO::Socket::Socks class. %cfg is like hash in the constructor. Only options listed below makes sence:
Timeout ConnectAddr ConnectPort BindAddr BindPort UdpAddr UdpPort SocksVersion SocksDebug SocksResolve AuthType RequireAuth Username Password AuthMethods
On success this method will return same $socket, but as IO::Socket::Socks object. On failure it will return undef (but socket will be still blessed to IO::Socket::Socks class). See example:
use IO::Socket;
use IO::Socket::Socks;
my $sock = IO::Socket::INET->new("$proxy_host:$proxy_port") or die $@;
$sock = IO::Socket::Socks->start_SOCKS($sock, ConnectAddr => "google.com", ConnectPort => 80) or die $SOCKS_ERROR;
version( )
Returns socks version for this socket
ready( )
Returns true when socket becomes ready to transfer data (socks handshake done), false otherwise. This is useful for non-blocking connect/bind. When this method returns false value you can determine what socks handshake need for with $SOCKS_ERROR variable. It may need for read, then $SOCKS_ERROR will be SOCKS_WANT_READ or need for write, then it will be SOCKS_WANT_WRITE.
Example:
use IO::Socket::Socks;
use IO::Select;
my $sock = IO::Socket::Socks->new(
ProxyAddr => 'localhost', ProxyPort => 1080, ConnectAddr => 'mail.com', ConnectPort => 80, Blocking => 0
) or die $SOCKS_ERROR;
my $sel = IO::Select->new($sock);
until ($sock->ready) {
if ($SOCKS_ERROR == SOCKS_WANT_READ) {
$sel->can_read();
}
elsif ($SOCKS_ERROR == SOCKS_WANT_WRITE) {
$sel->can_write();
}
else {
die $SOCKS_ERROR;
}
}
# you may want to return socket to blocking state by $sock->blocking(1)
$sock->syswrite("I am ready");
accept( )
Accept an incoming connection after bind request. On failed returns undef. On success returns socket. No new socket created, returned socket is same on which this method was called. Because accept(2) is not invoked on the client side, socks server calls accept(2) and proxify all traffic via socket opened by client bind request. You can call accept only once on IO::Socket::Socks client socket.
command( %cfg )
Allows one to execute socks command on already opened socket. Thus you can create socks chain. For example see ``EXAMPLES'' section.
%cfg is like hash in the constructor. Only options listed below makes sence:
ConnectAddr ConnectPort BindAddr BindPort UdpAddr UdpPort SocksVersion SocksDebug SocksResolve AuthType RequireAuth Username Password AuthMethods
Values of the other options (Timeout for example) inherited from the constructor. Options like ProxyAddr and ProxyPort are not included.
dst( )
Return (host, port, address_type) of the remote host after connect/accept or socks server (host, port, address_type) after bind/udpassoc.
Socks Server
new( %cfg )new_from_socket($socket, %cfg)
new_from_fd($socket, %cfg)
Creates a new IO::Socket::Socks server object. new_from_socket() is the same as new(), but allows one to create object from an existing socket (new_from_fd is new_from_socket alias). Both takes the following config hash:
SocksVersion => 4 for socks4, 5 for socks5 or [4,5] if you want accept both 4 and 5. Default is 5
Timeout => Timeout value for various operations
Blocking => Since IO::Socket::Socks version 0.6 you can perform non-blocking accept by
passing false value for this option. Default is true - blocking. See ready()
below for more details.
SocksResolve => For socks v5: return destination address to the client
in form of 4 bytes if true, otherwise in form of host
length and host name.
For socks v4: allow use socks4a protocol extension if
true and not otherwise.
This overrides value of $SOCKS4_RESOLVE or $SOCKS5_RESOLVE.
See also command_reply().
SocksDebug => This will cause all of the SOCKS traffic to
be presented on the command line in a form
similar to the tables in the RFCs. This overrides value
of $SOCKS_DEBUG variable. Boolean.
ProxyAddr => Local host bind address
ProxyPort => Local host bind port
UserAuth => Reference to a function that returns 1 if client
allowed to use socks server, 0 otherwise. For
socks5 proxy it takes login and password as
arguments. For socks4 argument is userid.
RequireAuth => Not allow anonymous access for socks5 proxy.
Listen => Same as IO::Socket::INET listen option. Should be
specified as number > 0.
The following options should be specified:
Listen ProxyAddr ProxyPort
Other options are facultative.
accept( )
Accept an incoming connection and return a new IO::Socket::Socks object that represents that connection. You must call command() on this to find out what the incoming connection wants you to do, and then call command_reply() to send back the reply.
version( )
Returns socks version for socket. It is useful when your server accepts both 4 and 5 version. Then you should know socks version to make proper response. Just call "version()" on socket received after "accept()".
ready( )
After non-blocking accept you will get new client socket object, which may be not ready to transfer data (if socks handshake is not done yet). ready() will return true value when handshake will be done successfully and false otherwise. Note, socket returned by accept() call will be always in blocking mode. So if your program can't block you should set non-blocking mode for this socket before ready() call: $socket->blocking(0). When ready() returns false value you can determine what socks handshake needs for with $SOCKS_ERROR variable. It may need for read, then $SOCKS_ERROR will be SOCKS_WANT_READ or need for write, then it will be SOCKS_WANT_WRITE.
Example:
use IO::Socket::Socks;
use IO::Select;
my $server = IO::Socket::Socks->new(ProxyAddr => 'localhost', ProxyPort => 1080, Blocking => 0)
or die $@;
my $select = IO::Select->new($server);
$select->can_read(); # wait for client
my $client = $server->accept()
or die "accept(): $! ($SOCKS_ERROR)";
$client->blocking(0); # !!!
$select->add($client);
$select->remove($server); # no more connections
while (1) {
if ($client->ready) {
my $command = $client->command;
... # do client command
$client->command_reply(IO::Socket::Socks::REPLY_SUCCESS, $command->[1], $command->[2]);
... # transfer traffic
last;
}
elsif ($SOCKS_ERROR == SOCKS_WANT_READ) {
$select->can_read();
}
elsif ($SOCKS_ERROR == SOCKS_WANT_WRITE) {
$select->can_write();
}
else {
die "Unexpected error: $SOCKS_ERROR";
}
}
command( )
After you call accept() the client has sent the command they want you to process. This function should be called on the socket returned by accept(). It returns a reference to an array with the following format:
[ COMMAND, ADDRESS, PORT, ADDRESS TYPE ]
command_reply( REPLY CODE, ADDRESS, PORT )
After you call command() the client needs to be told what the result is. The REPLY CODE is one of the constants as follows (integer value):
For socks v4 REQUEST_GRANTED(90): request granted REQUEST_FAILED(91): request rejected or failed REQUEST_REJECTED_IDENTD(92): request rejected becasue SOCKS server cannot connect to identd on the client REQUEST_REJECTED_USERID(93): request rejected because the client program and identd report different user-ids For socks v5 REPLY_SUCCESS(0): Success REPLY_GENERAL_FAILURE(1): General Failure REPLY_CONN_NOT_ALLOWED(2): Connection Not Allowed REPLY_NETWORK_UNREACHABLE(3): Network Unreachable REPLY_HOST_UNREACHABLE(4): Host Unreachable REPLY_CONN_REFUSED(5): Connection Refused REPLY_TTL_EXPIRED(6): TTL Expired REPLY_CMD_NOT_SUPPORTED(7): Command Not Supported REPLY_ADDR_NOT_SUPPORTED(8): Address Not Supported
HOST and PORT are the resulting host and port (where server socket responsible for this command bound).
Note: for 5 version "command_reply" will try to resolve passed address if "SocksResolve" has true value and passed address is domain name. To avoid this just pass ip address ("$socket->sockhost") instead of host name or turn off "SocksResolve" for this server. For version 4 passed host name will always be resolved to ip address even if "SocksResolve" has false value. Because this version doesn't support "ADDRESS" as domain name.
VARIABLES
$SOCKS_ERROR
This scalar behaves like $! in that if undef is returned. $SOCKS_ERROR is IO::Socket::Socks::Error object with some overloaded operators. In string context this variable should contain a string reason for the error. In numeric context it contains error code.$SOCKS4_RESOLVE
If this variable has true value resolving of host names will be done by proxy server, otherwise resolving will be done locally. Resolving host by socks proxy version 4 is extension to the protocol also known as socks4a. So, only socks4a proxy supports resolving of hostnames. Default value of this variable is false. This variable is not importable. See also `SocksResolve' parameter in the constructor.$SOCKS5_RESOLVE
If this variable has true value resolving of host names will be done by proxy server, otherwise resolving will be done locally. Note: some bugous socks5 servers doesn't support resolving of host names. Default value is true. This variable is not importable. See also `SocksResolve' parameter in the constructor.$SOCKS_DEBUG
Default value is $ENV{SOCKS_DEBUG}. If this variable has true value and no SocksDebug option in the constructor specified, then SocksDebug will has true value. This variable is not importable.$SOCKET_CLASS
With this variable you can get/set base socket class for "IO::Socket::Socks". By default it tries to use "IO::Socket::IP" 0.36+ as socket class. And falls back to "IO::Socket::INET" if not available. You can set $IO::Socket::Socks::SOCKET_CLASS before loading of "IO::Socket::Socks" and then it will not try to detect proper base class itself. You can also set it after loading of "IO::Socket::Socks" and this will automatically update @ISA, so you shouldn't worry about inheritence.CONSTANTS
The following constants could be imported manually or using `:constants' tag:
SOCKS5_VER SOCKS4_VER ADDR_IPV4 ADDR_DOMAINNAME ADDR_IPV6 CMD_CONNECT CMD_BIND CMD_UDPASSOC AUTHMECH_ANON AUTHMECH_USERPASS AUTHMECH_INVALID AUTHREPLY_SUCCESS AUTHREPLY_FAILURE ISS_UNKNOWN_ADDRESS # address type sent by client/server not supported by I::S::S ISS_BAD_VERSION # socks version sent by client/server != specified version ISS_CANT_RESOLVE # I::S::S failed to resolve some host REPLY_SUCCESS REPLY_GENERAL_FAILURE REPLY_CONN_NOT_ALLOWED REPLY_NETWORK_UNREACHABLE REPLY_HOST_UNREACHABLE REPLY_CONN_REFUSED REPLY_TTL_EXPIRED REPLY_CMD_NOT_SUPPORTED REPLY_ADDR_NOT_SUPPORTED REQUEST_GRANTED REQUEST_FAILED REQUEST_REJECTED_IDENTD REQUEST_REJECTED_USERID SOCKS_WANT_READ SOCKS_WANT_WRITE ESOCKSPROTO
SOCKS_WANT_READ, SOCKS_WANT_WRITE and ESOCKSPROTO are imported by default.
IPv6
Since version 0.66 "IO::Socket::Socks" supports IPv6 with help of IO::Socket::IP 0.36+. And will use "IO::Socket::IP" as base class if available. However you can force set "$SOCKET_CLASS = "IO::Socket::INET"" to use IPv4 only. See also ``$SOCKET_CLASS''FAQ
- How to determine is connection to socks server (client accept) failed or some protocol error occurred?
- You can check $! variable. If $! == ESOCKSPROTO constant, then it was error in the protocol. Error description could be found in $SOCKS_ERROR.
- How to determine which error in the protocol occurred?
-
You should compare $SOCKS_ERROR with constants below:
AUTHMECH_INVALID AUTHREPLY_FAILURE ISS_UNKNOWN_ADDRESS ISS_BAD_VERSION REPLY_GENERAL_FAILURE REPLY_CONN_NOT_ALLOWED REPLY_NETWORK_UNREACHABLE REPLY_HOST_UNREACHABLE REPLY_CONN_REFUSED REPLY_TTL_EXPIRED REPLY_CMD_NOT_SUPPORTED REPLY_ADDR_NOT_SUPPORTED REQUEST_FAILED REQUEST_REJECTED_IDENTD REQUEST_REJECTED_USERID
BUGS
The following options are not implemented:- GSSAPI authentication
- UDP server side support
Patches are welcome.
AUTHOR
Original author is Ryan EatmonNow maintained by Oleg G <[email protected]>
COPYRIGHT
This module is free software, you can redistribute it and/or modify it under the terms of LGPL.