The $50 Filer
Turning a wireless router into a fileserver with DD-WRT

Background

I’ve been using DD-WRT, a third-party firmware for wireless routers, on my Linksys WRT54GL for several years to provide DNS, DDNS, DHCP, and wireless. I recently picked up an Asus WL-520gU because it has a USB 2.0 port, a faster processor (240Mhz) and was on sale at Newegg for only $26. I was hoping to use the USB to mount an external USB drive and export it via Samba. Turns out there are tons of instructions on how exactly to do this, but I wasn’t able to find all the information in one place. The following is how I got up and running...

Getting Started

You’ll need your router, a USB storage device you want to share (it must be ext2/ext3 formatted to avoid kludging things), and the DD-WRT firmware. The DD-WRT version everyone says you need is the Eko NEWD mini build with USB. Visit here, find the build with the most recent date (sv10700 when I wrote this), and download the dd-wrt.v24-_NEWD_mini_usb.bin file.

Install the Asus tools that came with the router on a Windows box. Jack directly into the back of the router and run the Firmware Restoration tool. To prepare the router for the download, plug it in while holding down the reset button until the power button blinks on/off once a second. Click the “Upload” button. It should upload the firmware and reboot. Wait a minute or so and log into the web interface (http://192.168.1.1) to set your username/password (it seems to only like “root” as the username). On the Services tab, enable “SSHd”, "Core USB Support", "USB 2.0 Support", "USB Storage Support", "ext2/ext3 File System Support", and "FAT File System Support". Click "Save". On the Administration tab, enable "JFFS2" and click "Save". Wait a 30 seconds or so and then enable "Clean JFFS2". Click "Apply Settings" and NOT "Save".

Log into the router via SSH, run df -h, and you should see the following:

Filesystem Size Used Available Use% Mounted on
rootfs 2.1M 2.1M 0 100% /
/dev/root 2.1M 2.1M 0 100% /
/dev/mtdblock/4 896.0k 324.0k 572.0k 36% /jffs

If there is 0 available, try waiting a little longer or apply the “Clean JFFS2” setting again. Run the following commands to download the necessary startup script to mount your drive:

mkdir /jffs/etc
mkdir /jffs/etc/config
cd /jffs/etc/config
wget http://www.davidlaporte.org/files/optware.startup
chmod +x optware.startup

Reboot the router.

Installing Optware

SSH in and confirm your drive is mounted with df -h (you should see a /dev/scsi/host0/bus0/target0/lun0/part1 entry). Now run these commands to grab a profile and install Optware:

mkdir /opt/etc
cd /opt/etc
wget http://www.davidlaporte.org/files/profile
wget http://www.3iii.dk/linux/optware/optware-install-ddwrt.sh -O - | tr -d '\r' > /tmp/optware-install.sh
sh /tmp/optware-install.sh

If you get a bunch of errors about linking, you probably have it formatted as a FAT32 filesystem. Reformat it as ext3 and start over. If you didn’t see any obvious errors, the packaging system is installed. Run /opt/bin/ipkg-opt list to confirm - you should get a list of available packages.

Installing Samba

To install Samba, run /opt/bin/ipkg-opt install samba2. In my reading it was recommended to add the following between the killall and startup sections of the Samba startup script (/opt/etc/init.d/S80samba) to extend the life of flash devices:

if [ ! -d /tmp/samba ]; then
mkdir /tmp/samba
mkdir /tmp/samba/log
rm -rf /opt/var/log/samba
ln -s /tmp/samba/log /opt/var/log/samba
rm -rf /opt/var/samba
ln -s /tmp/samba /opt/var/samba
fi

To create a share, add the following to the end of /opt/etc/samba/smb.conf:

[USB]
path = /opt
public = yes
only guest = yes
writable = yes
printable = no

You will also need to change guest account from pcguest to root, and tweak workgroup, server string, and hosts allow.

This allows anyone to do anything on the share without authenticating! I use it on my home network and don’t care, but you may want to “fix” that. Reboot your router, SSH back in, and run smbclient -L 127.0.0.1 -N to make sure the shares are exported correctly.

Get Your Dork On!

It’s amazing that $50 will get you a pretty solid Linux box. There’s an onboard 4-pin serial header to play with, network-enabling a USB printer is as easy as running /opt/bin/ipkg-opt install p910nd (or so I’m told, I haven’t tried it), and there are tons of tools available via /opt/bin/ipkg-opt list to play with. Enjoy!