wiki.techinc.nl/includes/ProxyTools.php

<?php
/**
 * Functions for dealing with proxies
 * @package MediaWiki
 */

class ProxyTools {
	function getForwardedFor() {
		if( function_exists( 'apache_request_headers' ) ) {
			// More reliable than $_SERVER due to case and -/_ folding
			$set = apache_request_headers();
			$index = 'X-Forwarded-For';
		} else {
			// Subject to spoofing with headers like X_Forwarded_For
			$set = $_SERVER;
			$index = 'HTTP_X_FORWARDED_FOR';
		}
		if( isset( $set[$index] ) ) {
			return $set[$index];
		} else {
			return null;
		}
	}

	/** Work out the IP address based on various globals */
	function getIP() {
		global $wgSquidServers, $wgSquidServersNoPurge, $wgIP;

		# Return cached result
		if ( !empty( $wgIP ) ) {
			return $wgIP;
		}

		/* collect the originating ips */
		# Client connecting to this webserver
		if ( isset( $_SERVER['REMOTE_ADDR'] ) ) {
			$ipchain = array( $_SERVER['REMOTE_ADDR'] );
		} else {
			# Running on CLI?
			$ipchain = array( '127.0.0.1' );
		}
		$ip = $ipchain[0];

		# Get list of trusted proxies
		# Flipped for quicker access
		$trustedProxies = array_flip( array_merge( $wgSquidServers, $wgSquidServersNoPurge ) );
		if ( count( $trustedProxies ) ) {
			# Append XFF on to $ipchain
			$forwardedFor = ProxyTools::getForwardedFor();
			if ( isset( $forwardedFor ) ) {
				$xff = array_map( 'trim', explode( ',', $forwardedFor ) );
				$xff = array_reverse( $xff );
				$ipchain = array_merge( $ipchain, $xff );
			}
			# Step through XFF list and find the last address in the list which is a trusted server
			# Set $ip to the IP address given by that trusted server, unless the address is not sensible (e.g. private)
			foreach ( $ipchain as $i => $curIP ) {
				if ( array_key_exists( $curIP, $trustedProxies ) ) {
					if ( isset( $ipchain[$i + 1] ) && ProxyTools::isIPPublic( $ipchain[$i + 1] ) ) {
						$ip = $ipchain[$i + 1];
					}
				} else {
					break;
				}
			}
		}

		wfDebug( "IP: $ip\n" );
		$wgIP = $ip;
		return $ip;
	}

	/**
	 * Given an IP address in dotted-quad notation, returns an unsigned integer.
	 * Like ip2long() except that it actually works and has a consistent error return value.
	 */
	function IP2Unsigned( $ip ) {
		$n = ip2long( $ip );
		if ( $n == -1 || $n === false ) { # Return value on error depends on PHP version
			$n = false;
		} elseif ( $n < 0 ) {
			$n += pow( 2, 32 );
		}
		return $n;
	}

	/**
	 * Return a zero-padded hexadecimal representation of an IP address
	 */
	function IP2Hex( $ip ) {
		$n = ProxyTools::IP2Unsigned( $ip );
		if ( $n !== false ) {
			$n = sprintf( '%08X', $n );
		}
		return $n;
	}

	/**
	 * Determine if an IP address really is an IP address, and if it is public,
	 * i.e. not RFC 1918 or similar
	 */
	function isIPPublic( $ip ) {
		$n = ProxyTools::IP2Unsigned( $ip );
		if ( !$n ) {
			return false;
		}
	
		// ip2long accepts incomplete addresses, as well as some addresses
		// followed by garbage characters. Check that it's really valid.
		if( $ip != long2ip( $n ) ) {
			return false;
		}

		static $privateRanges = false;
		if ( !$privateRanges ) {
			$privateRanges = array(
				array( '10.0.0.0',    '10.255.255.255' ),   # RFC 1918 (private)
				array( '172.16.0.0',  '172.31.255.255' ),   #     "
				array( '192.168.0.0', '192.168.255.255' ),  #     "
				array( '0.0.0.0',     '0.255.255.255' ),    # this network
				array( '127.0.0.0',   '127.255.255.255' ),  # loopback
			);
		}

		foreach ( $privateRanges as $r ) {
			$start = ProxyTools::IP2Unsigned( $r[0] );
			$end = ProxyTools::IP2Unsigned( $r[1] );
			if ( $n >= $start && $n <= $end ) {
				return false;
			}
		}
		return true;
	}

	/**
	 * Forks processes to scan the originating IP for an open proxy server
	 * MemCached can be used to skip IPs that have already been scanned
	 */
	function proxyCheck() {
		global $wgBlockOpenProxies, $wgProxyPorts, $wgProxyScriptPath;
		global $wgUseMemCached, $wgMemc, $wgDBname, $wgProxyMemcExpiry;
		global $wgProxyKey;

		if ( !$wgBlockOpenProxies ) {
			return;
		}

		$ip = ProxyTools::getIP();

		# Get MemCached key
		$skip = false;
		if ( $wgUseMemCached ) {
			$mcKey = "$wgDBname:proxy:ip:$ip";
			$mcValue = $wgMemc->get( $mcKey );
			if ( $mcValue ) {
				$skip = true;
			}
		}

		# Fork the processes
		if ( !$skip ) {
			$title = Title::makeTitle( NS_SPECIAL, 'Blockme' );
			$iphash = md5( $ip . $wgProxyKey );
			$url = $title->getFullURL( 'ip='.$iphash );

			foreach ( $wgProxyPorts as $port ) {
				$params = implode( ' ', array(
							escapeshellarg( $wgProxyScriptPath ),
							escapeshellarg( $ip ),
							escapeshellarg( $port ),
							escapeshellarg( $url )
							));
				exec( "php $params &>/dev/null &" );
			}
			# Set MemCached key
			if ( $wgUseMemCached ) {
				$wgMemc->set( $mcKey, 1, $wgProxyMemcExpiry );
			}
		}
	}

	/**
	 * Convert a network specification in CIDR notation to an integer network and a number of bits
	 */
	function parseCIDR( $range ) {
		$parts = explode( '/', $range, 2 );
		if ( count( $parts ) != 2 ) {
			return array( false, false );
		}
		$network = ProxyTools::IP2Unsigned( $parts[0] );
		if ( $network !== false && is_numeric( $parts[1] ) && $parts[1] >= 0 && $parts[1] <= 32 ) {
			$bits = $parts[1];
		} else {
			$network = false;
			$bits = false;
		}
		return array( $network, $bits );
	}

	/**
	 * Check if an IP address is in the local proxy list
	 */
	function isLocallyBlockedProxy( $ip ) {
		global $wgProxyList;
		$fname = 'ProxyTools::isLocallyBlockedProxy';

		if ( !$wgProxyList ) {
			return false;
		}
		wfProfileIn( $fname );

		if ( !is_array( $wgProxyList ) ) {
			# Load from the specified file
			$wgProxyList = array_map( 'trim', file( $wgProxyList ) );
		}

		if ( !is_array( $wgProxyList ) ) {
			$ret = false;
		} elseif ( array_search( $ip, $wgProxyList ) !== false ) {
			$ret = true;
		} elseif ( array_key_exists( $ip, $wgProxyList ) ) {
			# Old-style flipped proxy list
			$ret = true;
		} else {
			$ret = false;
		}
		wfProfileOut( $fname );
		return $ret;
	}
}
?>