From 39051280a8e93b2af3a5b1bfee688ff30197bef9 Mon Sep 17 00:00:00 2001
From: Darold Gilles <gilles@darold.net>
Date: Tue, 26 Nov 2013 19:42:21 +0100
Subject: [PATCH] Add new directive DNSLookupTimeout to change the default
 timeout for DNS lookup. Add one second timeout when SquidAnalyzer look for an
 DNS name. Thanks to alex for the patch.

---
 README                |  6 ++++++
 SquidAnalyzer.pm      | 32 +++++++++++++++++++++++++++++++-
 doc/SquidAnalyzer.pod |  6 ++++++
 doc/squidanalyzer.3   |  7 ++++++-
 4 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/README b/README
index 940157c..1238ee1 100644
--- a/README
+++ b/README
@@ -189,6 +189,12 @@ CONFIGURATION
         DNS name instead. Note that you must have a working DNS resolution
         and that it can really slow down the generation of reports.
 
+    DNSLookupTimeout 1
+        If you have enabled UseClientDNSName and have lot of ip addresses
+        that do not resolve you may want to increase the DNS lookup timeout.
+        By default SquidAnalyzer will stop to lookup a DNS name after one
+        second.
+
     NetworkAlias network-aliases_file
         Set path to the file containing network alias name. Network are show
         as Ip addresses so if you want to display name instead create a file
diff --git a/SquidAnalyzer.pm b/SquidAnalyzer.pm
index 2d957dc..0460f3f 100644
--- a/SquidAnalyzer.pm
+++ b/SquidAnalyzer.pm
@@ -36,6 +36,9 @@ $ZCAT_PROG = "/bin/zcat";
 $BZCAT_PROG = "/bin/bzcat";
 $RM_PROG  = "/bin/rm";
 
+# DNS Cache
+my %CACHE = {};
+
 # Default translation srings
 my %Translate = (
 	'CharSet' => 'utf-8',
@@ -451,6 +454,7 @@ sub _init
 	$self->{TopUrlUser} = $options{TopUrlUser} || 0;
 	$self->{no_year_stat} = 0;
 	$self->{UseClientDNSName} = $options{UseClientDNSName} || 0;
+	$self->{DNSLookupTimeout} = $options{DNSLookupTimeout} || 1;
 
 	if ($self->{Lang}) {
 		open(IN, "$self->{Lang}") or die "ERROR: can't open translation file $self->{Lang}, $!\n";
@@ -601,6 +605,32 @@ sub _init
 
 }
 
+sub _gethostbyaddr
+{
+	my ($self, $ip) = @_;
+
+	return $ip unless $ip=~/\d+\.\d+\.\d+\.\d+/;
+
+	my $host = undef;
+	unless(exists $CACHE{$ip}) {
+		eval {
+			local $SIG{ALRM} = sub { die "timeout\n" };
+			alarm $self->{DNSLookupTimeout};
+			$host = gethostbyaddr(inet_aton($ip), AF_INET);
+			alarm 0;
+		};
+		if ($@) {
+			$CACHE{$ip} = undef;
+			#printf "_gethostbyaddr timeout : %s\n", $ip;
+		}
+		else {
+			$CACHE{$ip} = $host;
+			#printf "_gethostbyaddr success : %s (%s)\n", $ip, $host;
+		}
+	}
+	return $CACHE{$ip} || $ip;
+}
+
 sub _parseData
 {
 	my ($self, $time, $elapsed, $client, $code, $bytes, $url, $id, $type) = @_;
@@ -636,7 +666,7 @@ sub _parseData
 	# (login is equal to ip) and if client is an ip address
 	if ( ($id eq $client) && $self->{UseClientDNSName}) {
 		if ($client =~ /^\d+\.\d+\.\d+\.\d+$/) {
-			my $dnsname = gethostbyaddr(inet_aton($client), AF_INET);
+			my $dnsname = $self->_gethostbyaddr($client);
 			if ($dnsname) {
 				$id = $dnsname;
 			}
diff --git a/doc/SquidAnalyzer.pod b/doc/SquidAnalyzer.pod
index b14a13c..fc80722 100644
--- a/doc/SquidAnalyzer.pod
+++ b/doc/SquidAnalyzer.pod
@@ -199,6 +199,12 @@ the client ip address, this allow you to use the DNS name instead.
 Note that you must have a working DNS resolution and that it can really slow
 down the generation of reports.
 
+=item DNSLookupTimeout        1
+
+If you have enabled UseClientDNSName and have lot of ip addresses that do not
+resolve you may want to increase the DNS lookup timeout. By default SquidAnalyzer
+will stop to lookup a DNS name after one second.
+
 =item NetworkAlias network-aliases_file
 
 Set path to the file containing network alias name. Network are
diff --git a/doc/squidanalyzer.3 b/doc/squidanalyzer.3
index 3f7134a..0d51857 100644
--- a/doc/squidanalyzer.3
+++ b/doc/squidanalyzer.3
@@ -124,7 +124,7 @@
 .\" ========================================================================
 .\"
 .IX Title "SQUIDANALYZER 1"
-.TH SQUIDANALYZER 1 "2013-09-04" "perl v5.14.2" "User Contributed Perl Documentation"
+.TH SQUIDANALYZER 1 "2013-11-26" "perl v5.14.2" "User Contributed Perl Documentation"
 .\" For nroff, turn off justification.  Always turn off hyphenation; it makes
 .\" way too many mistakes in technical documents.
 .if n .ad l
@@ -330,6 +330,11 @@ thisA\*^\ directive. When you don't have authentication, the username is set to
 the client ip address, this allow you to use the \s-1DNS\s0 name instead.
 Note that you must have a working \s-1DNS\s0 resolution and that it can really slow
 down the generation of reports.
+.IP "DNSLookupTimeout        1" 4
+.IX Item "DNSLookupTimeout        1"
+If you have enabled UseClientDNSName and have lot of ip addresses that do not
+resolve you may want to increase the \s-1DNS\s0 lookup timeout. By default SquidAnalyzer
+will stop to lookup a \s-1DNS\s0 name after one second.
 .IP "NetworkAlias network\-aliases_file" 4
 .IX Item "NetworkAlias network-aliases_file"
 Set path to the file containing network alias name. Network are