<?php
//-------------------------------------------------------------------------
// BB-IMAP-Proxy.php - An IMAP Proxy to correct Blackberry IMAP Deficiencies
// Created by: Kevin Robert Keegan
//
// Description - This script creates a proxy IMAP server which corrects the
// IMAP deficiencies in the Blackberry Interenet Service.  The proxy runs as
// a middle man between BIS and your IMAP server forwarding and minimally
// editing the communication between BIS and your IMAP server.  The result is
// that BIS will now save copies of sent messages and move messages to the trash
// even if they are not contained in the base folder.  Additionally, this script
// allows for the use of a non-standard folder as the INBOX for an email account.
// This is designed for those of us who combine multiple email addresses into one
// IMAP account.
//
// Usage - I built this mostly for my use, but a skilled PHP user should be able
// to modify it to work for their needs.  If you are lucky you may only need to
// change the variables below in order to get this to work.
//
// Usage of Alternate Folder - To use an alternate folder as the INBOX use the
// following email address as the username for BIS.
//                   -+Other+-user@example.com
// Use the correct password for user@example.com.  This will make BIS think that
// the 'Other' folder is the INBOX for this account.  'Other' must be contained in
// the same parent(namespace) folder as 'Sent' and 'Trash'.
//
// Note - In my situation my IMAP server runs SSL.  There may be issues if your's
// doesn't. 1. The disconnection of a server socket may not be caught properly.
// 2. The data sent back and forth may be encrypted.
//
// Security note - when using with an SSL IMAP server this will create a hole
// where your password and other data are passed in clear text.  This will occur
// on the line between the BIS server and this proxy server.
//---------------------------------------------------------------------------

//------------------------- Edit This Stuff ---------------------------------

$X = true; //Set this to true to get troubleshooting output in the terminal

// Proxy Server Information
$address = '192.168.1.1'; // The IP to which the Proxy should Bind to
$port = 143;                // The port for incoming connections from BIS

// IMAP Server Information
$IMAP_address = "ssl://mail.example.com"; //The IMAP server name
	                                  //Use ssl:// or tcp://
$IMAP_port = 993; // The IMAP server port
$namespace = 'INBOX.'; // The folder which Sent and Trash are in.
$list_end = 'OK LIST completed'; // This is the command your IMAP server sends
								 // at the completion of the list command.
$sent_folder = "Sent"; // The name of your sent folder.
$trash_folder = "Trash"; // The name of your trash folder


//-------------- The Script, Editable by Experienced Users -------------------
ini_set('track_errors','1');

/* Allow the script to hang around waiting for connections. */
set_time_limit(0);

/* Turn on implicit output flushing so we see what were getting
/* as it comes in. */
ob_implicit_flush();

if (($sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)) === false) {
    echo "socket_create() failed: reason: " . socket_strerror(socket_last_error()) . "\n";
    exit;
}

socket_set_option($sock, SOL_SOCKET, SO_REUSEADDR, 1);

if (socket_bind($sock, $address, $port) === false) {
    echo "socket_bind() failed: reason: " . socket_strerror(socket_last_error($sock)) . "\n";
    exit;
}

if (socket_listen($sock, 5) === false) {
    echo "socket_listen() failed: reason: " . socket_strerror(socket_last_error($sock)) . "\n";
    exit;
}

// create a list of all the clients that will be connected to us..
// add the listening socket to this list
$clients = array($sock);
//And create a list of possible servers.
$servers = array();

if($X) $status = '';  // This is just used for screen output.

while(true) {
	// create a copy, so $clients doesnt get modified by socket_select()
    $read = $clients;

	// get a list of all the clients that have data to be read from
	// if there are no clients with data, go to next iteration
	$count = socket_select($read, $write = NULL, $except = NULL, 0);
	if ($count >= 1) {;

		// check if there is a client trying to connect------------ <
		if (in_array($sock, $read)) {
			// accept the client, and add him to the $clients array
			$clients[] = $newsock = socket_accept($sock);
			$key = array_search($newsock, $clients);
			if($X) echo "--New connection made--  $newsock -- C/S Pair:$key\n";
			if($X) echo "==== " . date("l, F jS Y - H:i:s") . " ====\n";
			// New Connection made Connect to imap server
			$servers[$key] = $newserv = fsockopen($IMAP_address, $IMAP_port, $errno, $errstr, 30);
			if (!$newserv) {
				if($X) echo "Failed to open Socket to server: $errstr ($errno)<br />\n";
				// So lets just shutdown this client then.
				disconnected_server($servers, $X, $newsock, $clients, $folder);
			}
			if($X) echo "--Connected to server-- $newserv -- C/S Pair:$key\n";

			if (!stream_set_timeout($servers[$key], 0, 500)){
				if($X) echo "####error unable to set timeout for the server socket###";
				// Lets just close this server and the client
				if($X) echo "--Disconnecting server-- $servers[$key] -- C/S Pair:$key \n";
				fclose($servers[$key]);
				disconnected_server($servers, $X, $newsock, $clients, $folder);
			}
			if (!socket_set_nonblock($newsock)){
				if($X) echo "###error unable to set non-blocking for the client socket###";
				// Lets just close this server and the client
				if($X) echo "--Disconnecting server-- $servers[$key] -- C/S Pair:$key \n";
				fclose($servers[$key]);
				disconnected_server($servers, $X, $newsock, $clients, $folder);
			}

			// remove the listening socket from the clients-with-data array
			$key = array_search($sock, $read);
			unset($read[$key]);
		} //End of new connection -----------------------------------

		// Read stuff from client to proxy--------------------------
		// loop through all the clients that have data to read from
		foreach ($read as $read_sock) {
			// read until stop or 1024 bytes
			// socket_read while show errors when the client is disconnected, so silence the error messages
			$data = @socket_read($read_sock, 1024, PHP_BINARY_READ);

			// check if the client is disconnected
			if (($data === '') && (socket_last_error($read_sock) != 11)) {
				// remove client for $clients array
				$key = array_search($read_sock, $clients);
				unset($clients[$key]);
				if($X) echo "--Client disconnected-- $read_sock -- C/S Pair:$key\n";
				// Disconnect the corresponding server
				if($X) echo "--Disconnecting server-- $servers[$key] -- C/S Pair:$key \n";
				fclose($servers[$key]);
				unset($servers[$key]);
				//Remove any possible folder reference
				unset($folder[$key]);
				// continue to the next client to read from, if any
				continue;
			}

			// check if there is any data after trimming off the spaces
			if (!empty($data)) {

				// send this to the server
				$key = array_search($read_sock, $clients);
				if ($status != $key . "client"){
					if($X) echo "\n--Client sent--  $read_sock -- C/S Pair:$key\n";
					$status = $key . "client";
				}
				if (preg_match( "/l LOGIN \"-\+(.*)\+-(.*\@.*)\" \"(.*)\"/"  , $data, $matches) > 0){
					if($X) echo "ORIGINAL DATA WAS: $data";
					$data = "l LOGIN \"$matches[2]\" \"$matches[3]\"\r\n";
					$folder[$key] = $matches[1];
				}
				if ((preg_match( "/s SELECT \"INBOX\"/"  , $data, $matches) > 0) && isset($folder[$key])){
					if($X) echo "ORIGINAL DATA WAS: $data";
					$data = "s SELECT \"" .$namespace. "$folder[$key]\"\r\n";
				}
				if (preg_match( "/a APPEND \"Sent\" \(\\\\Seen\) \{(\d*)\}/"  , $data, $matches) > 0){
					if($X) echo "ORIGINAL DATA WAS: $data";
					$data = "a APPEND \"" .$namespace . $sent_folder."\" (\Seen) \{$matches[1]}\r\n";
				}
				if (preg_match( "/c UID COPY (.*) \"Trash\"/"  , $data, $matches) > 0){
					if($X) echo "ORIGINAL DATA WAS: $data";
					$data = "c UID COPY $matches[1] \"" .$namespace . $trash_folder. "\"\r\n";
				}
				if($X) echo "$data";
				fputs($servers[$key], $data);

			}
		} // end of reading clients foreach-------------------------------
	} //end of clients conditional statement


	//Read stuff from server to proxy--------------------------<
	// loop through all the servers and check for data
	foreach ($servers as $read_sock) {
		// read until stop or 1024 bytes
		// fgets will show errors when the server is disconnected, so silence the error messages
		$data = @fgets($read_sock, 1024);

		// check if the server is disconnected
		if (strpos($php_errormsg, "SSL: fatal protocol error") !== false){
			disconnected_server($servers, $X, $read_sock, $clients, $folder);
			// continue to the next server to read from, if any
			continue;
		}

		// check if there is any data after trimming off the spaces
		if (!empty($data)) {

			// try and figure out which client this goes to?
			$key = array_search($read_sock, $servers);
			// send this to the client
			if ($status != $key . "server"){
				if($X) echo "\n--Server sent--  $read_sock -- C/S Pair:$key \n";
				$status = $key . "server";
			}
			if (strpos($data, $list_end) !== false){
				$append = '* LIST (\Marked \HasNoChildren) "." "Sent"' . "\r\n";
				$append .= '* LIST (\Marked \HasNoChildren) "." "Trash"' . "\r\n";
				if($X) echo $append;
				socket_write($clients[$key], $append, strlen($append));
			}
			if($X) echo "$data";
			socket_write($clients[$key], $data, strlen($data));

		}

	} // end of reading servers foreach-------------------------------

usleep(1000);

}
socket_close($sock);

function disconnected_server($servers, $X, $read_sock, $clients, $folder){
	// remove server from $servers array
	$key = array_search($read_sock, $servers);
	unset($servers[$key]);
	if($X) echo "--Connection to server lost-- $read_sock -- C/S Pair:$key \n";
	// Disconnect the corresponding client
	if($X) echo "-Disconnecting client--- $clients[$key] -- C/S Pair:$key \n";
	socket_close($clients[$key]);
	unset($clients[$key]);
	//Remove any possible folder reference
	unset($folder[$key]);
}
?>