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<?php
/*
* PHP TFTP Server
*
* Copyright (c) 2011 <mattias.wadman@gmail.com>
*
* MIT License:
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
*
* Extend TFTPServer class and then call loop method with UDP URL.
* Possible methods to override:
* exists($peer, $filename)
* Check if file exist, default always true.
* readable($peer, $filename)
* Check if file is readable, default always true.
* get($peer, $filename, $mode)
* Return content of file, default always false.
* Only called if both exists and readable returns true.
* writable($peer, $filename)
* Check if file is writable, default always false.
* put($peer, $filename, $mode, $content)
* Write content to file.
* Only falled if both exists and writable returns true.
*
* $peer is $ip:$port, source ip and port of client
* $filename is filename specified by client
* $mode is probably "octet" or "netascii"
* $content is file content
*
* The server support multiple concurrent read and writes, but the method calls
* are serialized, so make sure to return quickly.
*
* TODO:
* select must handle EINTR, how?
* multiple recv per select?
*
*/
/* Note about the Logger class:
* The "priority" and "minimum should be one of the constants used for syslog.
* See: http://php.net/manual/en/function.syslog.php
* They are: LOG_EMERG, LOG_ALERT, LOG_CRIT, LOG_ERR, LOG_WARNING, LOG_NOTICE,
* LOG_INFO, LOG_DEBUG
* Note that LOG_EMERG, LOG_ALERT, and LOG_CRIT are not really relevant to a
* tftp server - these represent instability in the entire operating system.
* Note that the number they are represented by are in reverse order -
* LOG_EMERG is the lowest, LOG_DEBUG the highest.
*/
abstract class Logger
{
function __construct($minimum)
{
$this->minimum = $minimum;
}
function shouldlog($priority)
{
// Note: this looks reversed, but is correct
// the priority must be AT LEAST the minimum,
// because higher priorities represent lower numbers.
return $priority <= $this->minimum;
}
abstract function log($priority, $message);
}
class Logger_Null extends Logger
{
function log($priority, $message)
{
}
}
class Logger_Syslog extends Logger
{
function log($priority, $message)
{
if($this->shouldlog($priority))
syslog($priority,$message);
}
}
class Logger_Filehandle extends Logger
{
private $priority_map = array(
LOG_DEBUG => "D",
LOG_INFO => "I",
LOG_NOTICE => "N",
LOG_WARNING => "W",
LOG_ERR => "E",
LOG_CRIT => "C",
LOG_ALERT => "A",
LOG_EMERG => "!"
);
function __construct($minimum, $filehandle, $dateformat = "r")
{
$this->filehandle = $filehandle;
$this->dateformat = $dateformat;
return parent::__construct($minimum);
}
function log($priority, $message)
{
if($this->shouldlog($priority))
fwrite($this->filehandle, date($this->dateformat) . ": " . $this->priority_map[$priority] . " $message\n");
}
}
class Logger_Filename extends Logger_Filehandle
{
function __construct($minimum, $filename, $dateformat = "r")
{
return parent::__construct($minimum, fopen($filename, "a"), $dateformat);
}
}
class Logger_Stderr extends Logger_Filehandle
{
function __construct($minimum, $dateformat = "r")
{
return parent::__construct($minimum, STDERR, $dateformat);
}
}
class Logger_Stdout extends Logger_Filehandle
{
function __construct($minimum, $dateformat = "r")
{
return parent::__construct($minimum, STDOUT, $dateformat);
}
}
class TFTPOpcode
{
public static function name($v)
{
static $names = array(TFTPOpcode::RRQ => "RRQ",
TFTPOpcode::WRQ => "WRQ",
TFTPOpcode::DATA => "DATA",
TFTPOpcode::ACK => "ACK",
TFTPOpcode::ERROR => "ERROR",
TFTPOpcode::OACK => "OACK");
if(isset($names[$v]))
return $names[$v];
else
return "UNKNOWN";
}
const RRQ = 1; // read request
const WRQ = 2; // write request
const DATA = 3; // send data
const ACK = 4; // ack data
const ERROR = 5;
const OACK = 6; // option ack, instead of first ACK/DATA
}
class TFTPError
{
const NOT_DEFINED = 0; // see error message instead of error code
const FILE_NOT_FOUND = 1;
const ACCESS_VIOLATION = 2;
const DISK_FULL = 3;
const ILLEGAL_OPERATION = 4;
const UNKNOWN_TID = 5; // unknown transfer (id is ip:port pair)
const FILE_ALREADY_EXISTS = 6;
const NO_SUCH_USER = 7;
const OACK_FAILURE = 8;
}
class TFTPTransferState
{
const READY = 1;
const SENDING_WAIT_OACK = 2;
const SENDING = 3;
const RECEIVING = 4;
const TERMINATING = 5;
}
abstract class TFTPTransfer {
public $state;
public $peer;
public $retransmit_timeout;
public $block_size;
public $tsize;
protected $_server; // TFTPServer reference
function __construct($server, $peer, $extensions)
{
$this->state = TFTPTransferState::READY;
$this->peer = $peer;
$this->retransmit_timeout = $server->retransmit_timeout;
$this->block_size = $server->block_size;
$this->tsize = 0;
$this->_server = $server;
if(isset($extensions["timeout"])) {
$timeout = (int)$extensions["timeout"];
if($timeout > 0 && $timeout < 256)
$this->retransmit_timeout = $timeout;
}
if(isset($extensions["blksize"])) {
$blksize = (int)$extensions["blksize"];
if($blksize > 0 && $blksize <= $server->max_block_size)
$this->block_size = $blksize;
}
// tsize is only checked for in write transfers
}
protected function log_debug($message)
{
$this->_server->log_debug($this->peer, $message);
}
protected function log_info($message)
{
$this->_server->log_info($this->peer, $message);
}
protected function log_warning($message)
{
$this->_server->log_warning($this->peer, $message);
}
protected function log_error($message)
{
$this->_server->log_error($this->peer, $message);
}
protected function terminal_info($error, $message)
{
$this->log_info($message);
$this->state = TFTPTransferState::TERMINATING;
return TFTPServer::packet_error($error, $message);
}
protected function terminal_error($op, $error, $message)
{
$this->log_debug("$op: $message");
$this->state = TFTPTransferState::TERMINATING;
return TFTPServer::packet_error($error, $message);
}
protected function illegal_operation($op, $message = "Illegal operation")
{
return $this->terminal_error($op, TFTPError::ILLEGAL_OPERATION, $message);
}
public function rrq($filename, $mode)
{
return $this->illegal_operation("RRQ");
}
public function wrq($filename, $mode)
{
return $this->illegal_operation("WRQ");
}
public function data($block, $data)
{
return $this->illegal_operation("DATA");
}
public function ack($block)
{
return $this->illegal_operation("ACK");
}
public function error($error, $message)
{
$this->log_debug("ERROR: $error: $message");
$this->state = TFTPTransferState::TERMINATING;
}
protected function use_extensions() {
return
$this->retransmit_timeout != $this->_server->retransmit_timeout ||
$this->block_size != $this->_server->block_size ||
$this->tsize != 0;
}
protected function packet_oack() {
$options = array();
if($this->retransmit_timeout != $this->_server->retransmit_timeout)
$options["timeout"] = (string)$this->retransmit_timeout;
if($this->block_size != $this->_server->block_size)
$options["blksize"] = (string)$this->block_size;
if($this->tsize != 0)
$options["tsize"] = (string)$this->tsize;
return TFTPServer::packet_oack($options);
}
}
class TFTPReadTransfer extends TFTPTransfer {
private $_last_recv_ack;
private $_last_sent_data;
private $_buffer;
private $_block;
private $_last_block;
function __construct($server, $peer, $extensions)
{
parent::__construct($server, $peer, $extensions);
$this->_last_recv_ack = time();
$this->_last_sent_data = $this->_last_recv_ack;
$this->_buffer = false;
$this->_block = 1;
$this->_last_block = 1;
$this->log_debug("new read transfer");
}
private function current_block()
{
return substr($this->_buffer,
($this->_block - 1) * $this->block_size,
$this->block_size);
}
private function packet_data_current()
{
$this->_last_sent_data = time();
if($this->state == TFTPTransferState::SENDING_WAIT_OACK)
return $this->packet_oack();
else
return TFTPServer::packet_data($this->_block, $this->current_block());
}
public function rrq($filename, $mode)
{
$this->log_debug("RRQ: filename $filename in $mode mode");
if($this->state != TFTPTransferState::READY)
return $this->illegal_operation("RRQ", "Not in ready state");
if(!$this->_server->exists($this->peer, $filename))
return $this->terminal_info(TFTPError::FILE_NOT_FOUND,
"File $filename does not exist");
if(!$this->_server->readable($this->peer, $filename))
return $this->terminal_info(TFTPError::ACCESS_VIOLATION,
"File $filename is not readable");
$this->_buffer = $this->_server->get($this->peer, $filename, $mode);
if($this->_buffer === false)
return $this->terminal_info(TFTPError::FILE_NOT_FOUND,
"Failed to read $filename");
$this->log_info("Reading $filename (" .
strlen($this->_buffer) . " bytes)");
if($this->use_extensions())
$this->state = TFTPTransferState::SENDING_WAIT_OACK;
else
$this->state = TFTPTransferState::SENDING;
$this->_last_block = floor(strlen($this->_buffer) /
$this->block_size) + 1;
$this->log_debug("RRQ: send first block or OACK");
return $this->packet_data_current();
}
public function ack($block)
{
if($this->state == TFTPTransferState::SENDING_WAIT_OACK) {
if($block != 0) {
$this->log_debug("ACK: waiting OACK ACK got block $block");
return false;
}
$this->state = TFTPTransferState::SENDING;
$this->log_debug("ACK: got OACK ACK, send first block");
return $this->packet_data_current();
}
if($this->state != TFTPTransferState::SENDING)
return $this->illegal_operation("ACK", "Not in sending state");
$this->log_debug("ACK: block $block");
$this->_last_recv_ack = time();
if($block < $this->_block) {
$this->log_debug("ACK: duplicate block $block");
// just ignore it
return false;
}
if($block > $this->_last_block)
return $this->illegal_operation("ACK",
"Block $block outside " .
"range 1-{$this->_last_block}");
if($block == $this->_last_block) {
$this->log_debug("ACK: last block, done");
$this->state = TFTPTransferState::TERMINATING;
return false;
}
// move to next block
$this->_block = $block + 1;
$this->log_debug("ACK: sending block {$this->_block}");
return $this->packet_data_current();
}
public function retransmit($now)
{
if($now - $this->_last_recv_ack > $this->_server->timeout) {
$this->log_debug("retransmit: timeout");
$this->state = TFTPTransferState::TERMINATING;
return false;
}
if($now - $this->_last_sent_data > $this->retransmit_timeout) {
$this->log_debug("retransmit: resending block {$this->_block} or OACK");
return $this->packet_data_current();
}
return false;
}
}
class TFTPWriteTransfer extends TFTPTransfer {
private $_last_sent_ack;
private $_last_recv_data;
private $_buffer;
private $_buffer_size;
private $_next_block;
private $_filename;
private $_mode;
function __construct($server, $peer, $extensions)
{
parent::__construct($server, $peer, $extensions);
$this->_last_sent_ack = time();
$this->_last_recv_data = $this->_last_sent_ack;
$this->_buffer = array();
$this->_buffer_size = 0;
$this->_last_recv_block = 0;
$this->_filename = false;
$this->_mode = false;
if(isset($extensions["tsize"]))
$this->tsize = (int)$extensions["tsize"];
$this->log_debug("new write transfer");
}
private function packet_ack_current()
{
$this->_last_sent_ack = time();
if($this->_last_recv_block == 0 && $this->use_extensions())
return $this->packet_oack();
else
return TFTPServer::packet_ack($this->_last_recv_block);
}
public function wrq($filename, $mode)
{
$this->log_debug("WRQ: filename $filename in $mode mode");
if($this->state != TFTPTransferState::READY)
return $this->illegal_operation("WRQ", "Not in ready state");
if(!$this->_server->writable($this->peer, $filename))
return $this->terminal_info(TFTPError::ACCESS_VIOLATION,
"File $filename is not writable");
if($this->tsize != 0 && $this->tsize > $this->_server->max_put_size)
return $this->terminal_info(TFTPError::DISK_FULL,
"File too big, " .
$this->tsize . "(tsize) > " .
$this->_server->max_put_size);
$this->state = TFTPTransferState::RECEIVING;
$this->_filename = $filename;
$this->_mode = $mode;
$this->_last_sent_ack = time();
$this->log_debug("WRQ: ack request");
if($this->use_extensions())
return $this->packet_oack();
else
return TFTPServer::packet_ack(0);
}
public function data($block, $data)
{
if($this->state != TFTPTransferState::RECEIVING)
return $this->illegal_operation("DATA", "Not in receiving state");
$this->log_debug("DATA: block $block");
$this->last_recv_data = time();
if($block <= $this->_last_recv_block) {
$this->log_debug("DATA: duplicate block $block");
// just ignore it
return false;
}
if($block != $this->_last_recv_block + 1)
return $this->illegal_operation("DATA",
"Expected block " .
($this->_last_recv_block + 1) .
" got $block");
$this->_last_recv_block = $block;
$this->_last_recv_data = time();
array_push($this->_buffer, $data);
$this->_buffer_size += strlen($data);
if($this->_buffer_size > $this->_server->max_put_size)
return $this->terminal_info(TFTPError::DISK_FULL,
"File too big, " .
$this->_buffer_size . " > " .
$this->_server->max_put_size);
if(strlen($data) < $this->block_size) {
$this->log_debug("DATA: last, done");
$this->state = TFTPTransferState::TERMINATING;
$this->log_info("Writing {$this->_filename} " .
"({$this->_buffer_size} bytes)");
$this->_server->put($this->peer, $this->_filename, $this->_mode,
implode("", $this->_buffer));
return $this->packet_ack_current();
}
$this->log_debug("DATA: ack block $block");
return $this->packet_ack_current();
}
public function retransmit($now)
{
if($now - $this->_last_recv_data > $this->_server->timeout) {
$this->log_debug("retransmit: timeout");
$this->state = TFTPTransferState::TERMINATING;
return false;
}
if($now - $this->_last_sent_ack > $this->retransmit_timeout) {
$this->log_debug("retransmit: reack block {$this->_last_recv_block}");
return $this->packet_ack_current();
}
return false;
}
}
class TFTPServer {
public $block_size = 512;
public $max_block_size = 65464; // max block size from rfc2348
public $timeout = 10;
public $retransmit_timeout = 1;
public $max_put_size = 10485760; // 10 Mibi
private $_socket_url;
private $_socket;
private $_transfers = array();
private $_logger = NULL;
function __construct($socket_url, $logger = NULL)
{
$this->_socket_url = $socket_url;
$this->_logger = $logger;
}
public function exists($peer, $filename)
{
return true;
}
public function readable($peer, $filename)
{
return true;
}
public function get($peer, $filename, $mode)
{
return false;
}
public function writable($peer, $filename)
{
return false;
}
public function put($peer, $filename, $mode, $content)
{
}
public function logger_log($priority, $message) {
if($this->_logger === NULL)
return;
$this->_logger->log($priority, $message);
}
public function log_debug($peer, $message)
{
$this->logger_log(LOG_DEBUG, "$peer $message");
}
public function log_info($peer, $message)
{
$this->logger_log(LOG_INFO, "$peer $message");
}
public function log_warning($peer, $message)
{
$this->logger_log(LOG_WARNING, "$peer $message");
}
public function log_error($peer, $message)
{
$this->logger_log(LOG_ERR, "$peer $message");
}
public static function packet_ack($block)
{
return pack("nn", TFTPOpcode::ACK, $block);
}
public static function packet_data($block, $data)
{
return pack("nn", TFTPOpcode::DATA, $block) . $data;
}
public static function packet_error($code, $message = "")
{
return pack("nn", TFTPOpcode::ERROR, $code) . $message . "\0";
}
public static function packet_oack($options)
{
$data = "";
foreach($options as $key => $value)
$data .= "$key\0$value\0";
return pack("n", TFTPOpcode::OACK) . $data;
}
public static function escape_string($str)
{
$b = "";
$l = strlen($str);
for($i = 0; $i < $l; $i++) {
$c = $str[$i];
if(ctype_print($c))
$b .= $c;
else
$b .= sprintf("\\x%'02x", ord($c));
}
return $b;
}
public function loop(&$error = false, $user = null)
{
$this->_socket =
stream_socket_server($this->_socket_url, $errno, $errstr,
STREAM_SERVER_BIND);
if(!$this->_socket) {
if($error !== false)
$error = "$errno: $errstr";
return false;
}
if($user != null) {
posix_seteuid($user["uid"]);
posix_setegid($user["gid"]);
}
stream_set_blocking($this->_socket, false);
return $this->loop_ex();
}
private function loop_ex()
{
$now = $last = time();
while(true) {
$read = array($this->_socket);
$r = stream_select($read, $write = null, $excpt = null, 1);
if($r === false) {
$this->log_error("server", "select returned false");
continue;
}
if(count($read) > 0) {
$packet = stream_socket_recvfrom($this->_socket,
65535, // max udp packet size
0, // no flags
$peer);
// ipv6 hack, convert to [host]:port format
if(strpos($peer, ".") === false) {
$portpos = strrpos($peer, ":");
$host = substr($peer, 0, $portpos);
$port = substr($peer, $portpos + 1);
$peer = "[$host]:$port";
}
$this->log_debug($peer, "request: " . strlen($packet). " bytes");
$this->log_debug($peer, "request: " .
TFTPServer::escape_string($packet));
$reply = $this->request($peer, $packet);
if($reply !== false) {
$this->log_debug($peer, "reply: " .
TFTPServer::escape_string($reply));
stream_socket_sendto($this->_socket, $reply, 0, $peer);
}
}
$now = time();
if($now != $last) {
$last = $now;
$this->retransmit($now);
}
}
}
private function retransmit($now)
{
foreach($this->_transfers as $peer => $transfer) {
$reply = $transfer->retransmit($now);
if($reply !== false) {
$this->log_debug($peer, "resend: " .
TFTPServer::escape_string($reply));
stream_socket_sendto($this->_socket, $reply, 0, $peer);
}
if($transfer->state == TFTPTransferState::TERMINATING)
unset($this->_transfers[$peer]);
}
}
private function request($peer, $packet)
{
if(strlen($packet) < 4) {
$this->log_debug($peer, "request: short packet");
return false;
}
$reply = false;
$transfer = false;
if(isset($this->_transfers[$peer])) {
$this->log_debug($peer, "request: existing transfer");
$transfer = $this->_transfers[$peer];
}
$fields = unpack("n", $packet);
$op = $fields[1];
$this->log_debug($peer, "request: opcode " .
TFTPOpcode::name($op) . " ($op)");
switch($op) {
case TFTPOpcode::WRQ:
case TFTPOpcode::RRQ:
$a = explode("\0", substr($packet, 2));
if(count($a) < 3 || $a[count($a) - 1] != "") {
$this->log_warning($peer, "request: malformed " .
TFTPOpcode::name($op));
return false;
}
$rawexts = array_slice($a, 2, -1);
// Cisco IP Phone 7941 (and possibly others) return an extra null
// at the end; a breach of RFC rfc2347. This is a workaround.
// If odd count strip last and continue if empty, else warn and ignore
if(count($rawexts) % 2 != 0) {
if(array_pop($rawexts)!="") {
$this->log_warning($peer, "request: malformed extension " .
"key/value pairs " . TFTPOpcode::name($op));
return false;
}
}
$extensions = array();
foreach(array_chunk($rawexts, 2) as $pair)
$extensions[strtolower($pair[0])] = $pair[1];
if($transfer === false) {
if($op == TFTPOpcode::RRQ)
$transfer = new TFTPReadTransfer($this, $peer, $extensions);
else
$transfer = new TFTPWriteTransfer($this, $peer, $extensions);
$this->_transfers[$peer] = $transfer;
}
if($op == TFTPOpcode::RRQ)
$reply = $transfer->rrq($a[0], $a[1]);
else
$reply = $transfer->wrq($a[0], $a[1]);
break;
case TFTPOpcode::ACK:
if(strlen($packet) != 4) {
$this->log_warning($peer, "request: malformed ACK");
return false;
}
$a = unpack("n", substr($packet, 2));
if($transfer === false) {
// do not warn, some clients like BSD tftp sends ack on read error
$this->log_debug($peer, "request: ack from unknwon peer");
} else
$reply = $transfer->ack($a[1]);
break;
case TFTPOpcode::DATA:
if(strlen($packet) < 4) {
$this->log_warning($peer, "request: malformed DATA");
return false;
}
$a = unpack("n", substr($packet, 2));
$data = substr($packet, 4, strlen($packet) - 4);
if($transfer === false) {
$this->log_warning($peer, "request: data from unknwon peer");
$reply = TFTPServer::packet_error(TFTPError::UNKNOWN_TID,
"Unknown TID for DATA");
} else
$reply = $transfer->data($a[1], $data);
break;
case TFTPOpcode::ERROR:
$a = unpack("n", substr($packet, 2, 2));
$message = substr($packet, 4, strlen($packet) - 5);
if($transfer === false)
$this->log_warning($peer, "request: error from unknwon peer, " .
"{$a[1]}:$message");
else
$transfer->error($a[1], $message);
break;
default:
break;
}
if($transfer !== false &&
$transfer->state == TFTPTransferState::TERMINATING) {
$this->log_debug($peer, "request: terminating");
unset($this->_transfers[$transfer->peer]);
}
return $reply;
}
}
?>