WebSocket: client does not response to server - php

Question

I am new to websocket.
I have made a simple websocket implementation on PHP. Handshaking works fine, and the connection is definitely on, since my server can get messages from client.
But, once I try to send message back to client, the client does not response at all.
Here is the code that mask messages and send it back to client.
function myProcess($user,$buffer)
{
//$buffer=unwrap($buffer);
console("Request Caught.");
console("Content Length: ".strlen($buffer));
console("Content: ".unmask($buffer));
console("First 8 bits: ".ord($buffer[0]));
console("Opcode: ".opcode($buffer,true));
//console("Full Text: ".$buffer);
//socket_write($user->socket,mask(unmask($buffer)));
console("Masking: ");
$tmp=unmask($buffer);
console($tmp);
$masked=mask($tmp);
opcode($masked);
for($i=0;$i<strlen($masked);$i++)
{
console($i.": ".ord($masked[$i]));
}
console("length: ".strlen($masked));
console("Sending Response: ");
console(socket_write($user->socket,$masked,strlen($masked)));
}
function mask($text)
{
$first8bit=0x81;
$header;
console("mask: payload length:".strlen($text));
if(strlen($text)<=125)
{
$header=pack("CC",$first8bit,strlen($text));
}
else if(strlen($text)<65536)
{
$header=pack("CCS",$first8bit,126,strlen($text));
}
else
{
$header=pack("CCN",$first8bit,127,strlen($text));
}
return $header.$text;
}
If the client send "hi" to server, server is going to simply reply "hi". And the captured packets with wireshark is 81 02 68 69. It seems the bits on the wire is just as the protocol says. If server trys to send a longer string, for example "hi from server", the client response with an error: undefined.
Can anyone help? Thanks a lot.
This is the code of server:
while(true){
$changed = $sockets;
socket_select($changed,$write=NULL,$except=NULL,NULL);
foreach($changed as $socket){
if($socket==$master){
console("Master Socket Changed.");
$client=socket_accept($master);
if($client<0){ console("socket_accept() failed"); continue; }
else{ connect($client); }
}
else{
console($socket." Socket Changed.");
$str=socket_read($socket,2048);
$user=getuserbysocket($socket);
if(strlen($str)==0) disconnect($socket);
else if(!$user->handshake){ dohandshake($user,$str); }
else
{
myProcess($socket,$str);
}
console("Comunication Ends Here.");
}
}
}
This is the calculation of accept section:
function calc_accept($key)
{
$tmp=$key."258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
$tmp=sha1($tmp,true);
//console($tmp);
$tmp=base64_encode($tmp);
//console($tmp);
return $tmp;
}
This does the handshake:
function dohandshake($user,$buffer){
console("\nRequesting handshake...");
console($buffer);
list($resource,$host,$origin,$strkey,$data) = getheaders($buffer);
console("Handshaking...");
$upgrade="HTTP/1.1 101 Switching Protocols\r\n".
"Upgrade: websocket\r\n".
"Connection: Upgrade\r\n".
"Sec-WebSocket-Accept: ".calc_accept($strkey)."\r\n\r\n";
socket_write($user->socket,$upgrade.chr(0),strlen($upgrade.chr(0)));
$user->handshake=true;
console($upgrade);
console("Done handshaking...");
return true;
}
These 2 function gets the handshake of client and get user object by a socket:
function getheaders($req){
$r=$h=$o=null;
if(preg_match("/GET (.*) HTTP/" ,$req,$match)){ $r=$match[1]; }
if(preg_match("/Host: (.*)\r\n/" ,$req,$match)){ $h=$match[1]; }
if(preg_match("/Origin: (.*)\r\n/",$req,$match)){ $o=$match[1]; }
if(preg_match("/Sec-WebSocket-Key: (.*)\r\n/",$req,$match)){ $key=$match[1]; }
if(preg_match("/\r\n(.*?)\$/",$req,$match)){ $data=$match[1]; }
return array($r,$h,$o,$key,$data);
}
function getuserbysocket($socket){
global $users;
$found=null;
foreach($users as $user){
if($user->socket==$socket){ $found=$user; break; }
}
return $found;
}

Answer 1

The format string for pack looks wrong for messages between 126 and 65536 bytes. Can you try changing
"CCS" - unsigned short (always 16 bit, machine byte order)
to
"CCn" - unsigned short (16-bit) in "network" (big-endian) order

Answer 2

I solved it.
To anyone whom is struggling on the strange problem, this is the answer:
DELETE chr(0) of socket_write($user->socket,$upgrade.chr(0),strlen($upgrade.chr(0))) from handshake function.
I will still mark simnoc's answer as correct one, because he inspired me. Thanks