OMAP Wireless Connectivity NLCP WLAN AP Configuration Scripts

Access Point Configuration scripts using "Host APD" commands

The following section provides information how to configure the EVM to work in Access point, how to set the AP to work with arbitrary Security mode also adding the DHCP server and NAT (Network Address Translation) capability in order to have an Access Point that can function as a WLAN router.
In that release we don’t have a GUI capability to configure the AP to any mode of operation therefore all the setting will be done using Terminal that is connected over the serial port to the EVM.
The following items will be covered:

1. Access Point configuration - Non Secured network
2. Access Point configuration - Secured network (WEP-40)
3. Access Point configuration - Secured network (WEP-128)
4. Access Point configuration - Secured network (WPA)
5. Access Point configuration - Secured network (WPA2)
6. Access Point configuration - Secured network (any WPA)
7. How to set the DHCP server on the AP
8. How to run The EVM in Access Point mode
9. How to Exit from Access Point mode

Hardware setting

Access point settings

The hostapd.conf file (located in folder /etc) defines the Soft AP settings.

Note: most common fields are:

1. “ssid” field, modify according to the requested SSID WiFi network, generated by the AP.
2. "channel" field, defines the channel that the AP will work on
3. "hw_mode" field, in case it is "g" then the AP works in 802.11g band
4. "beacon_int" field, is the Beacon interval
5. "dtim_period" field, is the DTIM period

for more detailed information on hostapd.conf, use the following link: <hostapd.conf information>

Access Point configuration - Band support

1. hw_mode=g - to support bg band
2. hw_mode=b - to support b only band
3. ieee80211n=1 - to support 802.11n band

Following are the main definitions that should be edited in that file

Step 1 - Configuring hostapd.conf

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

mv /etc/hostapd.conf /etc/hostapd.conf.bak

The editing above can be done by vi editor as follows:

1. vi /etc/hostapd.conf

2. The editor will be opened. Type the character 'i' to switch to editing mode.
3. Copy and paste the above content into the editor.
4. Hit 'esc' button to stop editing.
5. Type the sequence ":wq" in order to save and quit.

Create a new hostapd.conf with the following content:

Access Point configuration - Non Secured network

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
dump_file=/tmp/hostapd.dump
ctrl_interface=/var/run/hostapd
ctrl_interface_group=0
supported_rates=60 90 120 180 240 360 480 540
basic_rates=60 90 120 180 240
ssid=MAC_AP
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

Access Point configuration - Secured network (WEP-40)

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
dump_file=/tmp/hostapd.dump
ctrl_interface=/var/run/hostapd
ctrl_interface_group=0
ssid=zoomtest
max_num_sta=5
macaddr_acl=0
auth_algs=1
wep_default_key=0
wep_key0=1234567890
eapol_key_index_workaround=0
eap_server=0
own_ip_addr=127.0.0.1

Access Point configuration - Secured network (WEP-128)

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
dump_file=/tmp/hostapd.dump
ctrl_interface=/var/run/hostapd
ctrl_interface_group=0
ssid=zoomtest
max_num_sta=5
macaddr_acl=0
auth_algs=1
wep_default_key=2
wep_key0=1234567890
wep_key1=1234567890
wep_key2=CcCcCcCcCcCcCcCcCcCcCcCcCc
wep_key3=1234567890
wme_enabled=0
eapol_key_index_workaround=0
eap_server=0
own_ip_addr=127.0.0.1

Secured network (WPA)

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
dump_file=/tmp/hostapd.dump
ctrl_interface=/var/run/hostapd
ctrl_interface_group=0
ssid=zoomtest
max_num_sta=5
macaddr_acl=0
auth_algs=1
wme_enabled=0
eapol_key_index_workaround=0
eap_server=0
own_ip_addr=127.0.0.1
wpa=1
wpa_passphrase=12345678
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP

Access Point configuration - Secured network (WPA2)

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
dump_file=/tmp/hostapd.dump
ctrl_interface=/var/run/hostapd
ctrl_interface_group=0
ssid=zoomtest
max_num_sta=5
macaddr_acl=0
auth_algs=1
wme_enabled=0
eapol_key_index_workaround=0
eap_server=0
own_ip_addr=127.0.0.1
wpa=2
wpa_passphrase=12345678
wpa_key_mgmt=WPA-PSK
wpa_pairwise=CCMP

Access Point configuration - Secured network (any WPA)

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
dump_file=/tmp/hostapd.dump
ctrl_interface=/var/run/hostapd
ctrl_interface_group=0
ssid=zoomtest
max_num_sta=5
macaddr_acl=0
auth_algs=1
wme_enabled=0
eapol_key_index_workaround=0
eap_server=0
own_ip_addr=127.0.0.1
wpa=3
wpa_passphrase=12345678
wpa_key_mgmt=WPA-PSK
wpa_pairwise=CCMP TKIP

How to set the DHCP server on the AP

The file /etc/udhcpd.conf contains configuration information specific to the udhcp server.
Following are the main parameters:

• "start" field - The starting address of the IP lease block; default value: 192.168.0.20.
• "end" field - The ending address of the IP lease block; default value: 192.168.0.254.
• "interface" field - The udhcp server should listen on INTERFACE. The default is eth0, and we will modify it to wlan0.
• "dns" fiels - The list of DNS servers; In this example, the public google DNS servers were used.
• "subnet" field - The subnet mask
• "router" field - The list of routers; In this example, the SoftAP WLAN IP address is used.
• "lease" field - The lease time in seconds; In this example: 10 days.

For the following demo, create the udhcpd.conf file with the content below, store it in /etc folder, and modify some basic fields according to the expected DHCP behavior (such as “start”, “end” address etc.).

# Sample udhcpd configuration file (/etc/udhcpd.conf)
# The start and end of the IP lease block
start 		192.168.0.20	#default: 192.168.0.20
end		192.168.0.254	#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	192.168.0.1
option	lease	864000		# 10 days of seconds

Press the following to get a sample of <udhcpd.conf file>, unzip the file to get the udhcpd.conf file

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

mv /etc/udhcpd.conf /etc/udhcpd.conf.bak

and then edit the file by

vi /etc/udhcpd.conf

Create a new udhcpd.conf with the following content:

How to run The EVM in Access Point mode

Note: The wlan0 port IP address that is defined as "ifconfig wlan0 192.168.0.1" below, should be the same IP address as defined in the “router” field in the /etc/udhcpc.conf file
in order to run the Soft AP, run the following:

echo 1 > /proc/sys/net/ipv4/ip_forward
ifconfig wlan0 192.168.0.1
hostapd -B /etc/hostapd.conf -P /var/run/hostapd.pid
udhcpd /etc/udhcpd.conf
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

How to Exit from Access Point mode

follows the next commands in order to exit from Access Point mode and return to WLAN Station mode: first need to kill both the hostapd and the udhcpd, for that use ps command to verify what is the Process ID of hostapd and udhcpd

root@am37x-evm:/etc# ps
  PID USER       VSZ STAT COMMAND
 2702 root      4904 S    hostapd -B /etc/hostapd.conf -P /var/run/hostapd.pid
 2704 root      2936 S    udhcpd /etc/udhcpd.conf
 2714 root      3128 R    ps

once we have the Process ID, we can kiil it

kill -9 2702
kill -9 2704
echo 0 > /proc/sys/net/ipv4/ip_forward
iptables -F
ifconfig wlan0 down
iwconfig wlan0 mode managed
ifconfig wlan0 up

External links

• For more information on Soft AP (hostapd) configuration please use the following link <wl12xx hostapd configuration >

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