From dbe330298729cdaa9c07e72e8778daad0a87e1c3 Mon Sep 17 00:00:00 2001
From: Savetheinternet <savetheinternet@tinyboard.org>
Date: Sat, 3 Dec 2011 11:52:31 +1100
Subject: [PATCH] Avoid DNS timeouts by using `host` and cache if available

---
 inc/config.php    |  4 ++++
 inc/functions.php | 24 ++++++++++++++++++++++++
 mod.php           |  2 +-
 3 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/inc/config.php b/inc/config.php
index a2e5b8ae..e18f329f 100644
--- a/inc/config.php
+++ b/inc/config.php
@@ -75,6 +75,10 @@
 	// Use syslog() for logging all error messages and unauthorized login attempts.
 	$config['syslog'] = false;
 	
+	// Use `host` via shell_exec() to lookup hostnames, avoiding query timeouts. May not work on your system.
+	// Requires safe_mode to be disabled.
+	$config['dns_system'] = false;
+	
 /*
  * ====================
  *  Database settings
diff --git a/inc/functions.php b/inc/functions.php
index c79e3a68..db1b930a 100644
--- a/inc/functions.php
+++ b/inc/functions.php
@@ -487,6 +487,7 @@
 			$query->bindValue(':board', $board);
 			$query->execute() or error(db_error($query));
 		}
+		
 		if($query->rowCount() < 1 && $config['ban_cidr'] && !isIPv6()) {
 			// my most insane SQL query yet
 			$query = prepare("SELECT `set`, `expires`, `reason`, `board`, `uri`, `bans`.`id` FROM `bans` LEFT JOIN `boards` ON `boards`.`id` = `board` WHERE (`board` IS NULL OR `uri` = :board)
@@ -1472,4 +1473,27 @@
 		}
 	}
 	
+	function rDNS($ip_addr) {
+		global $config;
+		
+		if($config['cache']['enabled'] && ($host = cache::get('rdns_' . $ip_addr))) {
+			return $host;
+		}
+		
+		if(!$config['dns_system']) {
+			$host = gethostbyaddr($ip_addr);
+		} else {
+			$resp = shell_exec('host -W 1 ' . $ip_addr);
+			if(preg_match('/domain name pointer ([^\s]+)$/', $resp, $m))
+				$host = $m[1];
+			else
+				$host = $ip_addr;
+		}
+		
+		if($config['cache']['enabled'])
+			cache::set('rdns_' . $ip_addr, $host, 3600);
+		
+		return $host;
+	}
+	
 ?>
diff --git a/mod.php b/mod.php
index 34a540f7..453e6737 100644
--- a/mod.php
+++ b/mod.php
@@ -2408,7 +2408,7 @@
 			// View information on an IP address
 			
 			$ip = $matches[1];
-			$host = $config['mod']['dns_lookup'] ? gethostbyaddr($ip) : false;
+			$host = $config['mod']['dns_lookup'] ? rDNS($ip) : false;
 			
 			if(hasPermission($config['mod']['unban']) && isset($_POST['unban']) && isset($_POST['ban_id'])) {
 				removeBan($_POST['ban_id']);