Samuel Jacob's Weblog

Just another technical blog

Archive for the ‘Router NAS Linux’ Category

DIY – Wirless Router and NAS: Software Pieces

without comments

This is the followup post of DIY – RCN. Here I document about the different software used to make my RCN.

Operating System

linux-ubuntu There are two open source choices BSD(FreeBSD) or Linux(ubuntu). After few days of analysis I decided to go with Linux – because in my work I use FreeBSD. In either case I did not want to use FreeNAS or OpenFiler or any other ready made distro. Since I am familiar with Ubuntu, I decided to use the Ubuntu server version.

File System

Wanted to use ZFS on my main storage disk but it is not available on Linux yet, so decided to go with XFS. EXT3/4 on the boot disk because it is natively supported and no extra package needed. The boot media is 8GB flash disk.

Installation

Since there is no optical disk drive, installation should be through network or USB. Since most of the Linux distributions supports that I decided to use USB.

  1. Download Ubuntu 10.10 server
  2. Download Universal USB installer
  3. Create bootable install media using the installer
  4. Boot the system with boot media

Partitions

Although no data is going to be stored in the boot media, it would be good to have separate partitions to store the config files and home directory. Otherwise re-installation would wipe out all the data.

I chose to create 5 partitions

/     - EXT4 - 2GB
/usr  - EXT4 - 2GB
/var  - EXT4 - 2GB
/home - EXT4 - 1GB
swap  -      - 1GB

Management

Since this device will run headless only way to communicate with the system is through network interface. Having SSH access is good but still having a web interface for common administration access is better. Few Linux applications are available for that my choice is Webmin.

sudo vi /etc/apt/sources.list
wget http://www.webmin.com/jcameron-key.asc
sudo apt-key add jcameron-key.asc
sudo apt-get update
sudo apt-get install webmin

After this the machine can be controlled from local network – https://hostname:10000/

Shutdown

Shutting down the system should be easy. Since the storage is connected to the system it cant be power off directly. The file system data should be syncd first and using command line or web interface is not realistic. So programming the ATX power switch is the only way – acpid does that.

sudo apt-get install acpid

Storage

The goal was to create file based storage which is accessible from my home network. The NAS server should be big enough for at least next 2 years(1TB). It should be fast enough to view videos from it without flickering(64MB ondisk buffer). It should have hardware fault tolerance(RAID).

Although few of my desktop boards had RAID option in the BIOS menu, I never used it and never explored it. I thought RAID chipsets in a motherboard is equivalent to RAID controllers/adapters. It was one of the decideding factor I favoured for Gigabyte(GA-D425TUD) motherboard with JMicron RAID chipset over Intel(D525MO) motherboard.

After configuring RAID in the BIOS and starting Linux I realized it is not true raid. Because Linux recognized as fakeraid. In simple terms fakeraid is a firmware based RAID. That is all the work is still to be done in software yielding no performance benefit. Advantage of fakeraid is multiple OS which runs on same box can utiltize the same RAID. Since my setup wont have multiboot option, I dont want the fakeraid so decided to go with pure software RAID 0. Here is the steps to create software raid 0.

  1. Create software raid using multiple devices(md) interface.
  2. mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/sda /dev/sdb
  3. The above command will take some time (around 6 hours) because it needs to sync the contents of both disks.
    While it is doing that the status can be checked by using the following command.
  4. cat /proc/mdstat
  5. Then create a XFS file system on the md device
  6. mkfs.xfs /dev/md0
  7. Store the configuration
  8. <b>mdadm --detail --scan > /etc/mdadm/mdadm.conf
  9. Create mount point and add the mount information in the /etc/fstab
  10.      mkdir /mnt/raid
         echo "/dev/md0        /mnt/raid       xfs     defaults            1       2" >> /etc/fstab
       

Windows File Sharing

After this /mnt/raid can be made accessible to remote machines through either NFS or through Windows File Sharing. For Windows File Sharing samba service needed to installed. The following command installs samba server.
sudo apt-get install samba

After installing samba server it can be configured using webmin. Use webmin to configure samba “Servers”->”Samba File sharing”. Add the storage mount point here.

Router

The routing functionality is very simple – handle all 3 interfaces with some limitations.
RCN

  • First interface eth0 is a Gigabit ethernet interface which is directly connected to the a desktop computer.
  • Second interface eth1 is a Fast ethernet interface which is directly connected to internet(connected to a ADSL modem).
  • Third interface is 802.11n wireless network.

Network and IP

All interfaces are in different networks. All interface should get static IPv4 address while booting up. This router should provide dynamic IP to the other machines.

Modify network interface and dhcp configurations

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet static
address 192.168.1.2
netmask 255.255.255.0
gateway 192.168.100.2
post-up iptables-restore < /etc/iptables.up.rules
up /etc/init.d/dhcp3-server start

#wireless network
auto wlan0
iface wlan0 inet static
address 192.168.2.1
netmask 255.255.255.0
gateway 192.168.100.2
up /etc/init.d/dhcp3-server start

#wan interface
auto eth1
iface eth1 inet static
address 192.168.100.2
netmask 255.255.255.0
gateway 192.168.100.1
[/shell]

[shell tab='/etc/dhcp3/dhcpd.conf']
subnet 192.168.1.0 netmask 255.255.255.0 {
range 192.168.1.100 192.168.1.200;
option domain-name-servers 208.67.222.222, 208.67.220.220;
option routers 192.168.1.2;
option broadcast-address 192.168.1.255;
default-lease-time 600;
max-lease-time 7200;
}
subnet 192.168.2.0 netmask 255.255.255.0 {
range 192.168.2.100 192.168.2.200;
option domain-name-servers 208.67.222.222, 208.67.220.220;
option routers 192.168.2.1;
option broadcast-address 192.168.2.255;
default-lease-time 600;
max-lease-time 7200;
}
[/shell]
[/codegroup]

Finally enable forwarding in Linux kernel by setting a system tunable.
[shell]echo 1 > /proc/sys/net/ipv4/ip_forward

To set it during boot modify /etc/sysctl.conf

NAT - Network Address Translation

NAT is required on eth1 to translate addresses on any outgoing packets and incoming packets. For the iptable rules should be set correctly, the following script does that.

INTIF="eth0"
EXTIF="eth1"

#set default polices and flush
iptables -P INPUT ACCEPT
iptables -F INPUT
iptables -P OUTPUT ACCEPT
iptables -F OUTPUT
iptables -P FORWARD DROP
iptables -F FORWARD
#setup NAT
iptables -t nat -F
iptables -t nat -A POSTROUTING -o $EXTIF -j MASQUERADE

iptables -A FORWARD -i $EXTIF -o $INTIF -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A FORWARD -i $INTIF -o $EXTIF -j ACCEPT

INTIF1="wlan0"
iptables -A FORWARD -i $EXTIF -o $INTIF1 -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A FORWARD -i $INTIF1 -o $EXTIF -j ACCEPT

iptables -A FORWARD -i $INTIF -o $INTIF1 -j ACCEPT
iptables -A FORWARD -i $INTIF1 -o $INTIF -j ACCEPT

#unblock certain services
#webmin
iptables -A INPUT -p tcp -m tcp --dport 10000 -j ACCEPT

Wireless

wifiNow it is time to setup the wireless interface. Assuming the wireless are drivers are present in the kernel.
The other tool required is hostapd. hostapd implements IEEE 802.11 access point management.
hostapd configuration

interface=wlan0
driver=nl80211

ctrl_interface=/var/run/hostapd
ctrl_interface_group=0

ssid=rcnap
hw_mode=g
channel=11

ieee80211n=1
#ht_capab=[HT40-][SHORT-GI-40]

wpa_pairwise=TKIP CCMP
wpa=1

Written by samueldotj

March 12th, 2011 at 8:43 am

DIY – Wirless Router and NAS: Hardware bits

with one comment

I have replaced my Buffalo WRT-G54 wireless router with my own custom built router. This blog explains the details involved that process. I call this device as RCN (Router cum NAS).

Hardware

I began my hardware hunt 45 days back – it was difficult because of my requirements and availability in Indian Market.

Here is the initial requirement list I had(strike-through indicates I gave up that requirement because the items are too costly or not available in India):

  • Total board TDP should be less than 40 watts
  • Passively cooled
  • Mini-ITX form factor
  • Onboard RAID
  • DDR3 support
  • Dual core
  • Hardware should be available in India

Here is the final products I purchased:

Here is some pictures of my RCN

RCN 012

RCN 006

RCN 013

RCN 010

Interesting fact about WD10EARS is it use 4KB sectors instead of the conventional 512byte sectors. Since this is a breakthrough software support is not much there. Looks like these drives perform poor if not partitioned properly – Since my requirement demands creating single partition, I purchased this drive and it performs well.

Written by samueldotj

February 14th, 2011 at 8:20 am

Posted in Router NAS Linux