VAR-SOM-AM43 Wireless LAN AP

VAR-SOM-AM43 - WLAN Access Point

Configuring WLAN as access point

Configuring hostapd.conf

First, we will back up the existing hostapd.conf file by invoking:

$ mv /etc/hostapd.conf /etc/hostapd.conf.orig

Create a new hostapd.conf with the following content:

$ vi /etc/hostapd.conf

Copy/paste the following configuration file into /etc/hostapd.conf and save it:

interface=wlan0
driver=nl80211
channel=1
hw_mode=g
preamble=1
dtim_period=2
beacon_int=100
logger_syslog=-1
logger_syslog_level=2
logger_stdout=-1
logger_stdout_level=2
ctrl_interface=/var/run/hostapd
ctrl_interface_group=0
supported_rates=10 20 55 110 60 90 120 180 240 360 480 540
basic_rates=10 20 55 110
ssid=SoftAP_Role
max_num_sta=5
macaddr_acl=0
auth_algs=3
ieee80211d=0
uapsd_advertisement_enabled=1
wep_rekey_period=0
own_ip_addr=127.0.0.1
wpa_group_rekey=0
wpa_strict_rekey=0
wpa_gmk_rekey=0
wpa_ptk_rekey=0
#ap_table_max_size=255
#ap_table_expiration_time=60
eap_server=1
disassoc_low_ack=1
ap_max_inactivity=4294967295
country_code=US


For AP on 5GHz set to these values: 

channel=36
hw_mode=a
basic_rates=60 120 240 

Explanation:
1) interface - in that case will be wlan0, since wlan0 will take the role of AP
2) channel - should be the same as the commericial AP channel that the station (wlan0)is connected too (since AP and Station need to be in the same channel)
3) hw_mode=g - to support 2.4GHz, a - to support 5GHz
4) ieee80211n=1 - optional to support 802.11n band ssid - the AP SSID
5) basic_rates=10 20 55 110 (11B rates for 2.4GHz) , 60 120 240 (11G rates for 5GHz as not allowed to use 11B in 5GHz)

Configuring udhcpd.conf

First, we will back up the existing udhcpd.conf file by invoking:

$ mv /etc/udhcpd.conf /etc/udhcpd.conf.orig

Create a new udhcpd.conf with the following content: - opt router: is the Router IP address and have to be the same as was defined by ifconfig command, in that example it is 10.4.30.34

$ vi /etc/udhcpd.conf

Copy/paste the following configuration file into /etc/udhcpd.conf and save it:

# Sample udhcpd configuration file (/etc/udhcpd.conf)
# The start and end of the IP lease block
start 		10.4.30.40	#default: 192.168.0.20
end		10.4.30.48	#default: 192.168.0.254
# The interface that udhcpd will use
interface   wlan0		#default: eth0
#Examles
opt	dns	8.8.8.8  8.8.4.4 # public google dns servers
option	subnet	255.255.255.0
opt	router	10.4.30.34
option	lease	864000		# 10 days of

operate WLAN as AP (Run hostapd)

hostapd -B /etc/hostapd.conf -P /var/run/hostapd.pid

Expected results:

root@varsomam43:~# hostapd -B /etc/hostapd.conf -P /var/run/hostapd.pid
Configuration file: /etc/hostapd.conf
rfkill: Cannot open RFKILL control device
[  299.788240] wlcore: PHY firmware version: Rev 8.2.0.0.232
[  299.848324] wlcore: firmware booted (Rev 8.9.0.0.48)
[  299.870434] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
wlan0: interface state UNINITIALIZED->COUNTRY_UPDATE[  299.879690] cfg80211: Calling CRDA for country: US

root@varsomam43:~# [  299.937209] cfg80211: Regulatory domain changed to country: US
[  299.943264] cfg80211:  DFS Master region: FCC
[  299.947483] cfg80211:   (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time)
[  299.958044] cfg80211:   (2402000 KHz - 2472000 KHz @ 40000 KHz), (N/A, 3000 mBm), (N/A)
[  299.966366] cfg80211:   (5170000 KHz - 5250000 KHz @ 80000 KHz, 160000 KHz AUTO), (N/A, 1700 mBm), (N/A)
[  299.976874] cfg80211:   (5250000 KHz - 5330000 KHz @ 80000 KHz, 160000 KHz AUTO), (N/A, 2300 mBm), (0 s)
[  299.986617] cfg80211:   (5735000 KHz - 5835000 KHz @ 80000 KHz), (N/A, 3000 mBm), (N/A)
[  299.995290] cfg80211:   (57240000 KHz - 63720000 KHz @ 2160000 KHz), (N/A, 4000 mBm), (N/A)
[  300.017611] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready

Assign IP address to the wlan port, note that it has to be the same one as defined in the "udhcpd.conf" file in field "opt router"

$ ifconfig wlan0 10.4.30.34 netmask 255.255.255.0 up

Add NAT and DHCP server capability to the AP:

echo 1 > /proc/sys/net/ipv4/ip_forward
udhcpd /etc/udhcpd.conf
iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE

Enable NAT for internet sharing

Assumption: Internet connection is available on port eth0 and we want to share it with wlan0 incoming access point connections.

We type the following to enable internet sharing, in this case:

$ iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

Please see more details on http://processors.wiki.ti.com/index.php/WiLink8_WLAN_Demo:_Linux#AP_.28create_AP_with_no_security.29