<?php

/*
*	BrowserID	void
*	Generates a sort of identification tag based on the client's browser.
*	Is by no means secure, but it will stop most casual session hijackings.
*/
function BrowserRawID() {
	return $_SERVER['HTTP_USER_AGENT'];
}

function BrowserID() {
	return md5(BrowserRawID());
}

function IPClassA($ip) {
	return preg_replace('/^([0-3]+)\..*$/', '\1', $ip);
}

function ChatSessionInit() {
	// Set the session to last longer, and to work even if the browser is reopened.
	ini_set('session.gc_maxlifetime', $GLOBALS['chat_session_life']);
	//ini_set('session.save_path', '_inc/sessions');
	//ini_set('session.use_trans_sid', '0');

	session_name($GLOBALS['chat_session_name']);

	$empty = false;
	//echo "\n<!-- {$_COOKIE[$GLOBALS['chat_session_name']]} -->\n";
	if (empty($_COOKIE[$GLOBALS['chat_session_name']]) && empty($_REQUEST[$GLOBALS['chat_session_name']])) {
		$empty = true;
		echo '<!-- Empty SID. Assigning you one, then... -->';
		session_id(md5(uniqid(rand()).time()));
	}

	session_start();

	if (($empty == false) && empty($_SESSION['session_id'])) {
		session_regenerate_id(); // prevent fixation attacks
		echo '<!-- No, you are not allowed to supply your own Session ID. -->';
	}
	//echo "\n<!-- {$_SESSION['session_id']} -->\n";
	$_SESSION['session_id'] = session_id();
	//echo "<!-- {$_SESSION['session_id']} -->\n";
	if (!preg_match('@^[a-z0-9]{32}$@', $_SESSION['session_id'])) {
		ChatSessionRestart('Invalid Session ID', FALSE);
		return false;
	}

	if (empty($_SESSION['client_id'])) {
		$_SESSION['client_id']		= BrowserID();
		$_SESSION['client_id_raw']	= BrowserRawID();
	} else if ($_SESSION['client_id'] != BrowserID()) {
		$reason = 'Client BrowserID changed, possible session hijacking.';
		$reason .= "\n New ID: ".BrowserID().' :: '.BrowserRawID();
		$reason .= "\n Old ID: {$_SESSION['client_id']} :: {$_SESSION['client_id_raw']}";
		ChatSessionRestart($reason, FALSE);
		return false;
	}
	
	if (empty($_SESSION['chap'])) {
		$_SESSION['chap'] = array();
		$_SESSION['chap']['challenge'] = sha1(uniqid(rand()));
	}

	if (empty($_SESSION['security']))
		$_SESSION['security'] = 1;

	if (!is_array($_SESSION['host'])) {
		$_SESSION['host'] = array();
		$_SESSION['host']['ip']			= $_SERVER['REMOTE_ADDR'];
		$_SESSION['host']['addr']		= @gethostbyaddr($_SERVER['REMOTE_ADDR']);
		$_SESSION['host']['country']	= LookupIP2Country($_SERVER['REMOTE_ADDR']);
		//*
		if (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
			$_SESSION['host']['proxyip']		= $_SERVER['HTTP_X_FORWARDED_FOR'];
			$_SESSION['host']['proxyaddr']		= @gethostbyaddr($_SERVER['HTTP_X_FORWARDED_FOR']);
			$_SESSION['host']['proxycountry']	= LookupIP2Country($_SERVER['HTTP_X_FORWARDED_FOR']);
		}
		//*/
	}
	if ($_SESSION['security'] >= 2) {
		if ($_SESSION['host']['ip'] != $_SERVER['REMOTE_ADDR']) {
			if ($_SESSION['security'] == 4) {
				ChatSessionRestart('IP must not change when Session Security is at Level 4.', FALSE);
				return false;
			}
			if ($_SESSION['security'] == 3) {
				if (IPClassA($_SESSION['host']['ip']) != IPClassA($_SERVER['REMOTE_ADDR'])) {
					ChatSessionRestart('First quad of IP must not change when Session Security is at Level 3.', FALSE);
					return false;
				}
			}
			// FIXME: If it doesn't resolve it will compare the last 7 digits of the IP
			// which is not very correct to do.
			$host = @gethostbyaddr($_SERVER['REMOTE_ADDR']);
			if (substr($host, -7) == substr($_SESSION['host']['addr'], -7)) {
				$_SESSION['host']['ip']			= $_SERVER['REMOTE_ADDR'];
				$_SESSION['host']['country']	= LookupIP2Country($_SERVER['REMOTE_ADDR']);
			} else {
				ChatSessionRestart('Last 7 characters of the resolved hostname did not match.', FALSE);
				return false;
			}
		}
		/*
		if ($_SESSION['host']['proxyip'] != $_SERVER['HTTP_X_FORWARDED_FOR']) {
			$host = @gethostbyaddr($_SERVER['HTTP_X_FORWARDED_FOR']);
			if (substr($host, -7) == substr($_SESSION['host']['proxyaddr'], -7)) {
				$_SESSION['host']['proxyip']	= $_SERVER['HTTP_X_FORWARDED_FOR'];
			} else {
				ChatSessionRestart('Last 7 characters of the proxied hostname did not match.');
				return false;
			}
		}
		*/
	}

	if (!is_array($_SESSION['chats']))
		$_SESSION['chats'] = array();
	if (!is_array($_SESSION['imagebans']))
		$_SESSION['imagebans'] = array();

	//$_SESSION['client_start']	= time();
	//$_SESSION['client_timer']	= time()-$_SESSION['client_start'];
	$_SESSION['chats'][0]['ident'] = substr(md5($_SESSION['session_id']), 0, 8);
	$_SESSION['chats'][0]['oldname'] = $_SESSION['chats'][0]['username'];
	//if (!empty($_SESSION['chats'][0]['id']))
	//	$_SESSION['chats'][0]['ident'] = substr(md5($_SESSION['chats'][0]['id']), 0, 8);

	setcookie($GLOBALS['chat_session_name'], $_SESSION['session_id'], time()+$GLOBALS['chat_session_life'], '/', '.pjj.cc');

	foreach($_SESSION['chats'] as $key => $val) {
		if (($key > 0) && ($val['lasthit'] <= time()-900)) {
			unset($_SESSION['chats'][$key]);
		}
	}

	AddToViewers();
	session_write_close();
	session_start();
}

function ChatSessionKill($reason='') {
	//$_SESSION = array();
	//session_destroy();
	session_write_close();
	$_SESSION = array();

	if ($reason)
		echo "<!-- Session destroyed: {$reason} -->";
}

function ChatSessionRestart($reason='', $natural=TRUE) {
	if (!$natural) {
		$mail = $reason."\n\n".var_export($_SESSION, TRUE);
		mail('sessions@projectjj.com', 'ASR by '.$_SERVER['REMOTE_ADDR'], $mail);
	}
	ChatSessionKill($reason);
	session_id(md5(uniqid(time().'JJ'.rand())));
	ChatSessionInit();
}

	// Automatic session startup
	//mmcache_set_session_handlers();

	MMC_Lock('Session.'.$_COOKIE['ChatID']);
	ChatSessionInit();

?>