Upside Down Ternet
This article explains how to create a transparent Squid proxy server using imagemagick's mogrify to flip the images upside down.
Installation
Install the squid, apache, wget and imagemagick packages.
Configuration
Create flip.pl, place it in your /usr/local/bin folder and make it executable:
/usr/local/bin/flip.pl
#!/usr/bin/perl
$|=1;
$count = 0;
$pid = $$;
while (<>) {
@splitted=split(/ /,$_);
chomp $_;
if ($_ =~ /(.*\.jpg)/i) {
$url = $1;
system("/usr/bin/wget", "-q", "-O","/srv/http/images/$pid-$count.jpg", "$url");
system("/usr/bin/mogrify", "-flip","/srv/http/images/$pid-$count.jpg");
print "http://127.0.0.1/images/$pid-$count.jpg\n";
}
elsif ($_ =~ /(.*\.gif)/i) {
$url = $1;
system("/usr/bin/wget", "-q", "-O","/srv/http/images/$pid-$count.gif", "$url");
system("/usr/bin/mogrify", "-flip","/srv/http/images/$pid-$count.gif");
print "http://127.0.0.1/images/$pid-$count.gif\n";
}
elsif ($_ =~ /(.*\.png)/i) {
$url = $1;
system("/usr/bin/wget", "-q", "-O","/srv/http/images/$pid-$count.png", "$url");
system("/usr/bin/mogrify", "-flip","/srv/http/images/$pid-$count.png");
print "http://127.0.0.1/images/$pid-$count.png\n";
}
else {
print "$splitted[0]\n";
}
$count++;
}
Next, while not necessary, does clean up the Squid configuration file a lot making it easier on the eyes
# sed -i "/^#/d;/^ *$/d" /etc/squid/squid.conf
Now, edit your squid.conf file and append this to the bottom
squid.conf
url_rewrite_program /usr/local/bin/flip.pl
Also find the line for http_port and make it now read
Finally, we have to create the folders for the images to be flipped in and set their permissions
The directory where the images are to be stored must be owned by the proxy user. Finally, add the http user to the proxy group
Verify that the http user is a member of the proxy group
or
Router Setup
You will need to edit iptables on your router or gateway to redirect http traffic to your proxy.
If you have DD-WRT on your router, this is easily done by going to Administration -> Commands and pasting the following into the box.
#!/bin/sh PROXY_IP=192.168.1. PROXY_PORT=3128 LAN_IP=`nvram get lan_ipaddr` LAN_NET=$LAN_IP/`nvram get lan_netmask` iptables -t nat -A PREROUTING -i br0 -s $LAN_NET -d $LAN_NET -p tcp --dport 80 -j ACCEPT iptables -t nat -A PREROUTING -i br0 -s ! $PROXY_IP -p tcp --dport 80 -j DNAT --to $PROXY_IP:$PROXY_PORT iptables -t nat -I POSTROUTING -o br0 -s $LAN_NET -d $PROXY_IP -p tcp -j SNAT --to $LAN_IP iptables -I FORWARD -i br0 -o br0 -s $LAN_NET -d $PROXY_IP -p tcp --dport $PROXY_PORT -j ACCEPT
Starting
Start/enable httpd.service and .