Wireless Networking

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Static IP Address Allocation

File /etc/network/interfaces need to be modified in order to add a static wireless IP address

Here is an example: 

auto lo

iface lo inet loopback

iface usb0 inet dhcp

iface bnep0 inet dhcp

auto eth0

iface eth0 inet dhcp

iface eth1 inet dhcp

iface wlan0 inet dhcp

auto mwlan0
iface mwlan0 inet static

address xxx.xxx.xxx.xxx

netmask xxx.xxx.xxx.xxx
 
gateway xxx.xxx.xxx.xxx

network xxx.xxx.xxx.xxx

pre-up /sbin/iwconfig $IFACE essid "LINYSYS_FOR_EX" txpower 100mW


One of the issues while making changes to the file was that the information entered (Any modification) was not updated. Hence, it was booting up to the old setup. Please check numerous times if the change has been registered.

Marvell driver modifications for WiFi

Argon ST Network Systems has made some modifications to the Marvell wifi driver (netMicroSD -vx and probably WifiStix) which allow user applications to get at per-user RSSI via the "iwpriv" command which is in the buildroot. A zipball of source and an mcf25.ko kernel module which might work is at Element Products

This file contains source to modify the mcf25 driver (Marvell 88W8385 driver) to report SNR and NF information on a per peer basis rather than the standard aggregate SNR/NF information. It was created on build root 1559 and also tested on later build roots. User applications can then compute RSSI as required

README

Argon ST Network Systems ----------------------------

Author: Dell Kronewitter Date: 3/3/2008

Included in this tarball are: mcf25.ko README wlan_dev.h wlan_main.c wlan_rx.c wlan_wext.c wlan_wext.h

You'll find the included source files in the standard buildroot at gumstix-buildroot/build_arm_nofpu/src_cf8385/wlan

If you want to make mcf25.ko just replace the files with the versions found here.

I've rebuilt the kernel modules by removing gumstix-buildroot/build_arm_nofpu/src_cf8385/*.ko and doing a make from the base buildroot.

If you want to experiment quick I've provided the kernel module pre-compiled for the version 1559 gumstix buildroot.

On the target you can place the kernel module (mcf25.ko) at /lib/modules/2.6.21gum/extra/mcf25.ko (after saving the standard version, unless you're brave) and reboot.

You should then be able to use the new feature of the iwpriv command.

# iwpriv mwlan0 get_rf_table 31

mwlan0 get_rf_table:macaddr:<00:0B:6B:0C:2F:EE> SNR 047 NF 093 Last 42949519

after using your mwlan0 interface. For example

# ping 192.168.1.33

(The 31 is a host index. There are a maximum number of 32 hosts stored and they are filled from the back of the table first.)

The SNR and NF parameters are self explanatory and the Last parameter is in jiffies as described at

http://mail.nl.linux.org/kernelnewbies/2004-05/msg00184.html

So the last packet received above from <00:0B:6B:0C:2F:EE> has a SNR of 47, a Noise Floor of 93, and was at time 42949519.

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