Difference between revisions of "Wifi"

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{{todo|InProgress (10.20.2015-14:23->JJ+);(10.20.2015-13:43->JJ+);(10.23.2015-11:50->MD-);(10.26.2015-16:50->JJ+)|Jeffrey Jung| project=OE 5.0,InProgress,JJ,MD }}
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{{todo| Complete (10.20.2015-14:23->JJ+);(10.20.2015-13:43->JJ+);(10.23.2015-11:50->MD-);(10.26.2015-16:50->JJ+);(10.27.2015-15:30->JJ+); (10.28.2015-15:05->JJ+);(10.28.2015-16:35->MD-); (11.2.2015-14:45->JJ+); (11.3.2015-19:35->MD-); (11.4.2015-14:40->JJ+);(11.05.2015-15:40->MD+); (11.10.2015-15:05->JJ-);(11.13.2015-14:00->MG+);(11.13.2015-14:44->KY+)|Jeffrey Jung| project=OE 5.0,Complete,JJ,MD,MG }}
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{{#seo:
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{{#seo:wireless, wifi, networking
 
|title=Wireless Networking
 
|title=Wireless Networking
 
|titlemode=append
 
|titlemode=append
−
|keywords=
+
|keywords=Linux wifi,embedded wifi
 
|description=How to access a wireless network
 
|description=How to access a wireless network
 
}}
 
}}
−
<span style="background:#00FF00;color:#FF0000;font-size:300%"></span>
+
 
−
This guide will illustrate how to set up and connect to a wireless network using the ThinkPenguin Wireless N USB Adapter for GNU/Linux and the built-in WiFi on the SoM-200GS.
+
This guide will illustrate how to set up and connect to a wireless network using the ThinkPenguin Wireless N USB Adapter for GNU/Linux and the built-in WiFi on the SoM-200GS carrier.
 
__TOC__
 
__TOC__
 +
  
 
<!--Background Information-->
 
<!--Background Information-->
 
{{:Templateimpl:bg | initials=JJ | title=Wireless Networking | desc=How to access a wireless network | project=OE 5.0 }}  
 
{{:Templateimpl:bg | initials=JJ | title=Wireless Networking | desc=How to access a wireless network | project=OE 5.0 }}  
−
While some machines from EMAC are not natively designed to connect to wireless networds, a large amount of these systems do have USB ports. Using a wireless network USB adapter, like one found here at [https://www.thinkpenguin.com/gnu-linux/penguin-wireless-n-usb-adapter-gnu-linux-tpe-n150usb ThinkPenguin], the system can be modified to establish wireless network connections. This page describes the actions needed to take to connect to a wireless network either using a wireless network USB adapter or built-in Wi-Fi found on EMAC products like the SoM-200GS carrier. We chose to use the ThinkPenguin USB adapter for this page because it is targeted to work with most, if not all, Linux distributions.
+
While many boards from EMAC are not natively designed to connect to wireless networks, most of these systems do have USB ports. Using a USB wireless network adapter, a system can be equipped with wireless networking capability. Such a USB adapter can be ordered by contacting the [mailto:sales@emacinc.com sales team] here at EMAC. Request the product by its part number, PER-USB-00005-R.
  
−
<!-- DELETE THIS WARNING BEFORE SUBMITTING IT TO REVIEW -->
+
 
−
{{warning | A bit more background info would be nice. Why USB dongles?  Why ThinkPenguin?  etc}}
+
This page describes the actions needed to connect to a wireless network using either a wireless network USB adapter, or the built-in Wi-Fi found on EMAC products like the SoM-200GS carrier. We chose to use the ThinkPenguin USB adapter for this page because it is well supported by the Linux kernel.
  
  
Line 24: Line 25:
 
<!-- Set Up Instructions -->
 
<!-- Set Up Instructions -->
 
===Set Up===  
 
===Set Up===  
−
<!-- DELETE THIS WARNING BEFORE SUBMITTING IT TO REVIEW -->
+
Before the device can be connected to the network, some additional software may need to be installed. Boards with Wi-Fi built in should already have the proper software and drivers to support connecting to a wireless network. If so, skip to the [[#Wireless Networking|Wireless Networking]] section.
−
{{warning|These descriptions need to be fleshed out the same way you fleshed out sentences in the Getting Started document I just reviewed.}}
+
 
−
Before the device can be connected to the network, some additional software will need to be installed. In order to obtain the new packages, connect the system to a physical network. If your are going to be using the USB adapter for the connection, it may be plugged in at this time, although it may not have the proper drivers installed to the system yet.  
+
<cl>1. In order to obtain the new packages, connect the system to a physical network.
 
<br clear=all>
 
<br clear=all>
−
1. This process requires modifying some system files so start by enabling read and write permissions to the filesystem.
 
−
:{{cli | username=root | hostname=ipac9x25 | mount -o remount,rw /}}
 
−
2. A check for any updates is typically a good practice before installing new software. Us the opkg manager to install any updated software from the package list. 
 
−
:{{cli | username=root | hostname=ipac9x25 | opkg update }}
 
−
3. One of the best tools to establish the connection to wireless networks is the wpa-supplicant package. This supplicant will allow the system to make connections to WPA and WPA2 protected networks. Install this package with the opkg manager.
 
−
:{{cli | username=root | hostname=ipac9x25 | opkg install wpa-supplicant}}
 
−
4. If using the USB adapter, the appropriat drivers may need to be installed. The ThinkPenguin USB adapter requires the installment of the linux-firmware-ath9k package. 
 
−
:{{cli | username=root | hostname=ipac9x25 | opkg install linux-firmware-ath9k}}
 
−
5. If using built-in Wi-Fi, the marvel license and linux-firmware-sd8787 packages will need to be installed. 
 
−
{{clo | indent=2}}
 
−
{{clio | opkg install linux-firmware-marvel-license | username=root | hostname=som9g45 }}
 
−
{{clio | opkg install linux-firmware-sd8787 | username=root | hostname=som9g45}}
 
−
{{clos}}
 
−
6. Independent of using buiilt-in Wi-Fi or an adapter, the iw and wireless-tools packages will complete the needed software to get a connection started.
 
−
{{clo | indent=2}}
 
−
{{clio | opgk install iw | username=root | hostname=ipac9x25}}
 
−
{{clio | opkg install wireless-tools | username=root | hostname=ipac9x25 }}
 
−
{{clos}}
 
  
−
{{warning | The above should be in just one continuous cli output box, so that it looks like it does in real life.  Hit edit to look at the wiki markup to see how I did this on this page: [[Installing_LILO]].
+
* This process requires modifying some system files, so start by enabling read and write permissions to the filesystem.  
−
<br />
+
{{cli | indent=2 | mount -o remount,rw / | hostname=ipac9x25 }}
−
Also note the use of the <code><nowiki><cl></nowiki></code> tag in the above referenced page. This is for the Continuous Lists extension.  You need to make use of this for your lists.  There should be documentation on it if you use google.}}
+
 
 +
* A check for any updates to the package list is typically a good practice before installing new software. Use the <code>opkg</code> manager to update the package list. 
 +
{{cli | indent=2 | opkg update | hostname=ipac9x25 }}
 +
 
 +
* One of the best tools to establish the connection to wireless networks is the <code>wpa-supplicant</code> package. This supplicant will allow the system to make connections to WPA and WPA2 protected networks. Install this package with the <code>opkg</code> tool.  
 +
{{cli | indent=2 | opkg install wpa-supplicant | hostname=ipac9x25 }}  
  
−
7. Upon successful installation of all required packages, the system will need to be rebooted to take advantage of the new packages.  
+
* Install the wireless firmware
 +
* If using the USB adapter, the appropriate firmware may need to be installed. The ThinkPenguin USB adapter requires the installation of the <code>linux-firmware-ath9k</code> package.
 +
{{cli | indent=2 | opkg install linux-firmware-ath9k | hostname=ipac9x25}}
  
−
{{warning | Why do they have to plug this in upon log in? Why can't they keep it plugged in?  It's not going to be usable for our customers if they have to manually plug it in after logging in.}}
+
  * The firmware package for the built-in Wi-Fi on EMAC's 200GS carrier board is <code>linux-firmware-sd8787</code>.  
 +
{{cli | indent=2 | opkg install linux-firmware-sd8787}}
  
−
{{warning | This step ^^ logically belongs in the next section, since sections should stand alone.}}
+
* Independent of whether you're connecting with an adapter or using built-in capabilities, the <code>iw</code> and <code>wireless-tools</code> packages will complete the needed software to get a connection started.
 +
{{cli | indent=2 | opgk install iw | hostname=ipac9x25}}
 +
{{cli | indent=2 | opkg install wireless-tools | hostname=ipac9x25 }}  
 +
</cl>
  
 +
All the necessary software required to make the wireless connection has now been obtained. The USB adapter can now be plugged in and will be recognized by the operating system.
 +
<!-- Wireless Networking -->
 
{{:Templateimpl:using | initials=JJ | title=Wireless Networking | desc=How to access a wireless network | project=OE 5.0 }}  
 
{{:Templateimpl:using | initials=JJ | title=Wireless Networking | desc=How to access a wireless network | project=OE 5.0 }}  
  
−
Using the packages that have just been installed, the system can be connected to the wireless network.<br />
 
−
1. Changes to some configuration files will be necessary, so mount the filesystem to read and write permisions.
 
−
:{{cli | username=root | hostname=ipac9x25 | mount -o remount,rw /}}
 
  
−
2. Wireless networks can be found using the can option of iw.
+
Using the packages that have just been installed, the system can be connected to the wireless network.<br/>
−
:{{cli | username=root | hostname=ipac9x25 | iw dev wlan0 scan}}  
+
<cl>1. Changes to some configuration files will be necessary, so remount the root filesystem with read and write permissions.
−
: A detailed list of the nearby networks will be printed out to the terminal. To identify teh SSIDs and respective signal strengths of the network(s) easier, pipe the iw command with the scan option into grep using keywords "SSID" or "signal". The closer the value of the signal strength is to 0, the stronger the connection.
+
{{cli | indent=2 |  mount -o remount,rw / | hostname=ipac9x25}}
−
:[[File:Scanning_with_iw.png|600px|left|thumb|Terminal output of scanning for wireless networks with iw command]]
+
 
−
<br clear=all>
+
* Wireless networks can be found using the scan option of <code>iw</code>.
 +
{{cli | indent=2 | iw dev wlan0 scan | hostname=ipac9x25}}  
 +
: A detailed list of the nearby networks will be printed out to the terminal. To identify the SSIDs and respective signal strengths of the network(s) more easily, pipe the output of the <code>iw scan</code> command through <code>grep</code> to scan for the keywords "SSID" or "signal". The closer the value of the signal strength is to 0, the stronger the connection.
 +
{{clo | indent=2}}
 +
{{clio| iw dev wlan0 scan {{!}} grep SSID|hostname=ipac9x25}}
 +
:SSID: EMAC-A
 +
{{clio| iw dev wlan0 scan {{!}} grep signal|hostname=ipac9x25}}
 +
:signal: -78.00dBm
 +
{{clio||hostname=ipac9x25}}
 +
{{clos}}
 +
 
 +
<br/>
 +
The <code>/etc/wpa_supplicant.conf</code> file will need to be modified to provide the necessary connection information, the details of which depend upon the type of encryption used for the wireless network.
 +
<br/>
  
−
The <code>/etc/wpa_supplicant.conf</code> file will need to be modified in a specific manner depending on the protection type of the network.
+
* For an open network, uncomment the following lines in <code>/etc/wpa_supplicant.conf</code> and fill in the correct SSID for the network to which the machine should connect.
−
3. For an open network, you'll just need to uncomment the lines in <code>/etc/wpa_supplicant.conf</code> <br />
+
<syntaxhighlight lang=bash>
−
<pre>
 
 
###open network
 
###open network
 
#network={
 
#network={
−
#      ssid="your-ssid" (optional)
+
#      ssid="SSID"
 
#      scan_ssid=1
 
#      scan_ssid=1
 
#      key_mgmt=NONE
 
#      key_mgmt=NONE
 
#}  
 
#}  
−
</pre>
+
</syntaxhighlight>
 +
 
 +
* Networks protected by either WEP or WPA2 encryption will need a pre-shared key (PSK), which is generated for the specific network and its password. To get the PSK, use <code>wpa_passphrase</code> with the SSID and password for the desired network as arguments. Copy the last psk line and paste into the <code>/etc/wpa_supplicant.conf</code> file.
 +
{{clo|indent=2}}
 +
{{clio | indent=2 | wpa_passphrase SSID Password |hostname=ipac9x25}}
 +
network={
 +
:ssid="SSID"
 +
:&#35;psk="Password"
 +
:psk=b99d2c0fb66194f93ad52b71051e1095dc76e12529321334b3feb18332608eb7
 +
}
 +
{{clos}}
  
−
{{warning | Instead of using the <code><nowiki><pre></nowiki></code> tag, you should use the <code><nowiki><syntaxhighlight></nowiki></code> tag.  We use this tag consistently to ensure all such text looks alike.  It will provide syntax highlighting for a variety of scripting languages, and may work to provide syntax highlighting for this config file using the shell/bash language.
+
* The contents of the <code>/etc/wpa_supplicant.conf</code> should now look similar to the following:
 +
{{clo|indent=2}}
 +
{{clio | cat /etc/wpa_supplicant.conf | hostname=ipac9x25}}
 +
network={
 +
:ssid="SSID"
 +
:proto=WPA
 +
:key_mgmt=WPA-PSK
 +
:psk=b99d2c0fb66194f93ad52b71051e1095dc76e12529321334b3feb18332608eb7
 +
}<br />
 +
{{clio||hostname=ipac9x25}}
 +
{{clos}}
 
<br />
 
<br />
−
  See [[LILO_Overview]] for a page where this extension is used.  Documentation on this plugin is available from MediaWiki: https://www.mediawiki.org/wiki/Extension:SyntaxHighlight_GeSHi  Note that the version that we have installed still uses GeSHi as its engine. }}
 
  
−
4. For a WEP password protected network, use <code>wpa_passphrase</code> to generate the private shared key(psk).
+
* The {{icli | /etc/init.d/wpa_supplicant start | hostname=ipac9x25}} command will attempt to establish a connection with the network.  
−
:[[File:Wpa_passphrase.png|600px|left|thumb|Terminal output when using the wpa_passphrase command]]
 
  
−
{{warning | These should not be screenshots.  You should copy and paste the text, and use the <code>cli</code> template set to display multi-line output, as can be seen in the LILO page I linked in this page earlier. Also, look at what I've enclosed in code tags.  You need to check through the document for any command or filename, and enclose it within <code><nowiki><code></code></nowiki></code> tags.}}
+
: As the command is running, watch the terminal output for the status of the connection. A connection has been established when output stops and the last line reads:
 +
{{clo | indent=2}}IPv6 ADDRCONF(NETDEV_CHANGE):wlan0: link becomes ready{{clos}}
  
−
<br clear=all>
+
:A connection has failed if output to the terminal continues and the following line is seen repeatedly:
−
: SSID is the SSID of the preferred network found when scanning with iw. Password is the password to connect to the network. 
+
{{clo | indent=2}}IPv6: ADDRCONF(NETDEV_UP):wlan0: link is not ready{{clos}}
−
5. Highlight the psk and copy it.<br />
 
−
6. Edit /etc/wpa_supplicant.conf to have the appropriate SSID and psk <br />
 
−
:[[File:Wpasupplicantconf.png|600px|left|thumb|Editing /etc/wpa_supplicant.conf with vim]]
 
−
<br clear=all>
 
  
 +
:'''Successful connection''' (waiting a full minute to ensure output to the terminal stopped); <br />
 +
{{clo|indent=2}}
 +
{{clio| /etc/init.d/wpa-supplicant start| hostname=ipac9x25}}
 +
Successfully initialized wpa_supplicant<br/>
 +
rfkill: Cannot open RFKILL control device<br/>
 +
{{clio| wlan0: authenticate with 1c:7e:e5:40:10:fd| hostname=ipac9x25}}
 +
wlan0: send auth to 1c:7e:e5:40:10:fd (try 1/3)<br/>
 +
wlan0: send auth to 1c:7e:e5:40:10:fd (try 2/3)<br/>
 +
wlan0: authenticated<br/>
 +
wlan0: associating with AP with corrupt beacon<br/>
 +
wlan0: associate with 1c:7e:e5:40:10:fd (try 1/3)<br/>
 +
wlan0: RX AssocResp from 1c:7e:e5:40:10:fd (capab=0x431 status=0 aid=6)<br/>
 +
wlan0: associated<br/>
 +
IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
 +
{{clos}}
 +
:'''Failed connection''' (waiting more than a minute as output continues to print to the terminal). The repeated lines indicate an issue establishing the connection. <br />
 +
{{clo|indent=2}}
 +
{{clio|/etc/init.d/wpa-supplicant start| hostname=ipac9x25}}
 +
Successfully initialized wpa_supplicant                                       
 +
IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready                           
 +
{{clio| IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready|hostname=ipac9x25}}       
 +
cfg80211: Calling CRDA to update world regulatory domain<br/>
 +
IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready<br/>                 
 +
cfg80211: Calling CRDA to update world regulatory domain<br/>                 
 +
IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready<br/>                 
 +
IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready<br/>                       
 +
cfg80211: Calling CRDA to update world regulatory domain<br/>                 
 +
IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready<br/>                 
 +
IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready<br/>                       
 +
cfg80211: Calling CRDA to update world regulatory domain<br/>                 
 +
IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready<br/>                 
 +
IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready<br/>                     
 +
cfg80211: Calling CRDA to update world regulatory domain<br/>                 
 +
IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready<br/>                 
 +
IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready<br/>                       
 +
cfg80211: Calling CRDA to update world regulatory domain<br/>                 
 +
IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready<br/>                 
 +
IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready<br/>                       
 +
cfg80211: Calling CRDA to update world regulatory domain<br/>                 
 +
IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready<br/>
 +
{{clos}}
 +
:A failed connection is likely the result of an improper password. Use <code>wpa_passphrase</code> to make sure you have the right psk for the password.
  
−
7. Make the connection to the network using the path /etc/init.d/wpa_supplicant with the argument <code>start</code>.  
+
* The <code>ifconfig</code> command will be used to determine that the device is wirelessly connected to the network. Look to see that <code>wlan0</code> has an IP address.
−
:{{cli | username=root | hostname=ipac9x25 | /etc/init.d/wpa_supplicant start}}  
+
{{clop|indent=2}}wlan0  Link encap:Ethernet HWaddr A8:54:B2:42:89:8D
−
: Give the command some time to establish the connection and watch the terminal output. A connection has been established when output stops and the last line reads:
+
:::inet addr:10.0.4.148 Bcast:10.0.255.255 Mask:255.255.0.0
−
{{clo | indent=2}}IPv6 ADDRCONF(NETDEV_CHANGE):wlan0: link becomes ready{{clos}}
+
:::UP BROADCAST RUNNING MULTICAST MTU:1500 METRIC:1
−
A connection has failed if the following is seen repeatedly and output to the terminal continues:
+
:::RX packets:3395 errors:0 dropped:6 overruns:0 frame:0
−
{{clo | indent=2}}IPv6: ADDRCONF(NETDEV_UP):wlan0: link is not ready{{clos}}
+
:::TX packets:60 errors:0 dropped:0 overruns:0 carrier:0
−
<br />
+
:::collisions:0 txqueuelen:1000
−
:'''Successful connection''' (waiting a full minute to ensure output to the terminal stopped); <br /> [[File:Connectionsuccess.png|600px|left|thumb|Successful connection terminal output]] <br clear=all>
+
:::RX bytes:346619 (338.4 KiB) TX bytes:6318 (6.1 Kib){{closp}}   
−
:'''Failed connection''' (waiting more than a minute as output continues to print to the terminal). The highlighted line and the repeated lines indicate an issue establishing the connection. <br />
 
−
:[[File:Wifi_connection_failed.png|600px|left|thumb|Failed connection terminal output]]
 
  
−
{{warning | Again, none of these should be screenshots. Change them all to multiline output using the <code><nowiki>{{clo}} {{clos}} {{clio}} {{cli}} {{icli}}</nowiki></code> etc. templates, as described in [[EMACTemplatesInternalPg]]. Note that you can click on any of the template links in that page to get more info and some examples.}}
+
* Disconnect any physical connections from the system and ping to [http://www.emacinc.com www.emacinc.com] to verify that the system can wirelessly connect to the Internet. <br />
 +
{{clop|indent=2}}
 +
{{cliop| ping -c 3 www.emacinc.com | hostname=ipac9x25}}
 +
PING www.emacinc.com (172.16.0.10): 56 data bytes
 +
64 bytes from 172.16.0.10: seq=0 ttl=63 time=1.910 ms
 +
64 bytes from 172.16.0.10: seq=1 ttl=63 time=1.748 ms
 +
64 bytes from 172.16.0.10: seq=2 ttl=63 time=2.061 ms
  
−
<br clear=all>
+
--- www.emacinc.com ping statistics ---
−
8. Confirm there is an IP address under wlan0 with the ifconfig command <br />
+
3 packets transmitted, 3 packets received, 0% packet loss
−
:[[File:Wlan0_ip_address.png|600px|left|thumb|ifconfig showing that wlan0 does have an IP address]] <br clear=all>
+
round-trip min/avg/max = 1.748/1.906/2.061 ms
−
9. Disconnect any Ethernet connections and ping to [http://www.emacinc.com www.emacinc.com] to verify that the system can wirelessly connect to the Internet. <br />
+
{{cliop||hostname=ipac9x25}}{{closp}}
−
:[[File:Pingemac.png|600px|left|thumb|Sending and receiving packets from www.emacinc.com]]
 
 
<br clear=all>  
 
<br clear=all>  
 +
</cl>
 +
<!-- {{:Templateimpl:examples | initials=JJ | title=Wireless Networking | desc=How to access a wireless network | project=OE 5.0 }} -->
  
−
<!-- {{:Templateimpl:examples | initials=JJ | title=Wireless Networking | desc=How to access a wireless network | project=OE 5.0 }} -->
+
== Troubleshooting ==
 +
If your come across any issues communicating though the network, try these suggestions as starting points to resolve the problem(s).
 +
* View the <code>/etc/resolv.conf</code> file to view the DNS servers provided from the DHCP server.
 +
* Inspect the routing table using the <code>route</code> command, as shown here:
 +
{{clop | indent=2}}
 +
{{cliop|hostname=ipac9x25|user=root|route -n}}
 +
Kernel IP routing table
 +
Destination    Gateway        Genmask        Flags Metric Ref    Use Iface
 +
0.0.0.0        10.0.2.1        0.0.0.0        UG    0      0        0 eth0
 +
10.0.0.0        0.0.0.0        255.255.0.0     U    1      0        0 eth0
 +
{{cliop|hostname=ipac9x25|user=root|}} {{closp}}
  
 
{{:Templateimpl:conclusion | initials=JJ | title=Wireless Networking | desc=How to access a wireless network | project=OE 5.0 }}  
 
{{:Templateimpl:conclusion | initials=JJ | title=Wireless Networking | desc=How to access a wireless network | project=OE 5.0 }}  
−
This page walks through the procedure to connect a module to a wireless network via a WiFi adapter or built-in wireless, as well as acquiring the necessary software tools to make the connection for the first time.
+
After connecting to a network the first time, the system will be able to connect to the same network when rebooted or powered on. Connecting to a new network will require going through the procedures set out under the [[#Wireless Networking|Wireless Networking]] section to revise the network settings.
−
<br clear=all>
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This page walked the reader through the procedure to connect a machine to a wireless network via a USB Wifi adapter or built-in wireless, and the process to acquire the necessary software tools to make the connection for the first time. While there are plenty of USB wireless adapters available for sale, we used an adapter intended for use on Linux machines with a driver supported by EMAC OE Linux. Other USB wireless adapters may be used to connect EMAC devices to wireless networks, but they will often face issues with driver support or other compatibility issues. Requests to purchase the adapter should be sent to [mailto:sales@emacinc.com sales@emacinc.com]; please include a reference to the EPN, PER-USB-00005-R, when sending a request to purchase this adapter.
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* [[OE50:Packages | EMAC OE 5.X Release Information]]
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Latest revision as of 15:46, 13 November 2015

TODO: {{#todo: Complete (10.20.2015-14:23->JJ+);(10.20.2015-13:43->JJ+);(10.23.2015-11:50->MD-);(10.26.2015-16:50->JJ+);(10.27.2015-15:30->JJ+); (10.28.2015-15:05->JJ+);(10.28.2015-16:35->MD-); (11.2.2015-14:45->JJ+); (11.3.2015-19:35->MD-); (11.4.2015-14:40->JJ+);(11.05.2015-15:40->MD+); (11.10.2015-15:05->JJ-);(11.13.2015-14:00->MG+);(11.13.2015-14:44->KY+)|Jeffrey Jung|OE 5.0,Complete,JJ,MD,MG}}

This guide will illustrate how to set up and connect to a wireless network using the ThinkPenguin Wireless N USB Adapter for GNU/Linux and the built-in WiFi on the SoM-200GS carrier.


Background

While many boards from EMAC are not natively designed to connect to wireless networks, most of these systems do have USB ports. Using a USB wireless network adapter, a system can be equipped with wireless networking capability. Such a USB adapter can be ordered by contacting the sales team here at EMAC. Request the product by its part number, PER-USB-00005-R.


This page describes the actions needed to connect to a wireless network using either a wireless network USB adapter, or the built-in Wi-Fi found on EMAC products like the SoM-200GS carrier. We chose to use the ThinkPenguin USB adapter for this page because it is well supported by the Linux kernel.


General Information

Set Up

Before the device can be connected to the network, some additional software may need to be installed. Boards with Wi-Fi built in should already have the proper software and drivers to support connecting to a wireless network. If so, skip to the Wireless Networking section.

  1. In order to obtain the new packages, connect the system to a physical network.

  2. This process requires modifying some system files, so start by enabling read and write permissions to the filesystem.

    root@ipac9x25:~# mount -o remount,rw /

  3. A check for any updates to the package list is typically a good practice before installing new software. Use the opkg manager to update the package list.

    root@ipac9x25:~# opkg update

  4. One of the best tools to establish the connection to wireless networks is the wpa-supplicant package. This supplicant will allow the system to make connections to WPA and WPA2 protected networks. Install this package with the opkg tool.

    root@ipac9x25:~# opkg install wpa-supplicant

  5. Install the wireless firmware

    • If using the USB adapter, the appropriate firmware may need to be installed. The ThinkPenguin USB adapter requires the installation of the linux-firmware-ath9k package.

    root@ipac9x25:~# opkg install linux-firmware-ath9k

    • The firmware package for the built-in Wi-Fi on EMAC's 200GS carrier board is linux-firmware-sd8787.

    root@som9x25:~# opkg install linux-firmware-sd8787

  6. Independent of whether you're connecting with an adapter or using built-in capabilities, the iw and wireless-tools packages will complete the needed software to get a connection started.

    root@ipac9x25:~# opgk install iw
    root@ipac9x25:~# opkg install wireless-tools

All the necessary software required to make the wireless connection has now been obtained. The USB adapter can now be plugged in and will be recognized by the operating system.

Wireless Networking

Using the packages that have just been installed, the system can be connected to the wireless network.

  1. Changes to some configuration files will be necessary, so remount the root filesystem with read and write permissions.

    root@ipac9x25:~# mount -o remount,rw /

  2. Wireless networks can be found using the scan option of iw.

    root@ipac9x25:~# iw dev wlan0 scan
    A detailed list of the nearby networks will be printed out to the terminal. To identify the SSIDs and respective signal strengths of the network(s) more easily, pipe the output of the iw scan command through grep to scan for the keywords "SSID" or "signal". The closer the value of the signal strength is to 0, the stronger the connection.
    root@ipac9x25:~# iw dev wlan0 scan | grep SSID
    SSID: EMAC-A
    root@ipac9x25:~# iw dev wlan0 scan | grep signal
    signal: -78.00dBm
    root@ipac9x25:~#


    The /etc/wpa_supplicant.conf file will need to be modified to provide the necessary connection information, the details of which depend upon the type of encryption used for the wireless network.

  3. For an open network, uncomment the following lines in /etc/wpa_supplicant.conf and fill in the correct SSID for the network to which the machine should connect. 

    ###open network
#network={
#      ssid="SSID"
#      scan_ssid=1
#       key_mgmt=NONE
#}

  4. Networks protected by either WEP or WPA2 encryption will need a pre-shared key (PSK), which is generated for the specific network and its password. To get the PSK, use wpa_passphrase with the SSID and password for the desired network as arguments. Copy the last psk line and paste into the /etc/wpa_supplicant.conf file.

    root@ipac9x25:~# wpa_passphrase SSID Password

    network={

    ssid="SSID"
    #psk="Password"
    psk=b99d2c0fb66194f93ad52b71051e1095dc76e12529321334b3feb18332608eb7

    }

  5. The contents of the /etc/wpa_supplicant.conf should now look similar to the following:

    root@ipac9x25:~# cat /etc/wpa_supplicant.conf

    network={

    ssid="SSID"
    proto=WPA
    key_mgmt=WPA-PSK
    psk=b99d2c0fb66194f93ad52b71051e1095dc76e12529321334b3feb18332608eb7

    }

    root@ipac9x25:~#


  6. The root@som9x25:~# /etc/init.d/wpa_supplicant start command will attempt to establish a connection with the network.

    As the command is running, watch the terminal output for the status of the connection. A connection has been established when output stops and the last line reads:
    IPv6 ADDRCONF(NETDEV_CHANGE):wlan0: link becomes ready
    A connection has failed if output to the terminal continues and the following line is seen repeatedly:
    IPv6: ADDRCONF(NETDEV_UP):wlan0: link is not ready
    Successful connection (waiting a full minute to ensure output to the terminal stopped);
    root@ipac9x25:~# /etc/init.d/wpa-supplicant start

    Successfully initialized wpa_supplicant
    rfkill: Cannot open RFKILL control device

    root@ipac9x25:~# wlan0: authenticate with 1c:7e:e5:40:10:fd

    wlan0: send auth to 1c:7e:e5:40:10:fd (try 1/3)
    wlan0: send auth to 1c:7e:e5:40:10:fd (try 2/3)
    wlan0: authenticated
    wlan0: associating with AP with corrupt beacon
    wlan0: associate with 1c:7e:e5:40:10:fd (try 1/3)
    wlan0: RX AssocResp from 1c:7e:e5:40:10:fd (capab=0x431 status=0 aid=6)
    wlan0: associated
    IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready

    Failed connection (waiting more than a minute as output continues to print to the terminal). The repeated lines indicate an issue establishing the connection.
    root@ipac9x25:~# /etc/init.d/wpa-supplicant start

    Successfully initialized wpa_supplicant IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready

    root@ipac9x25:~# IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready

    cfg80211: Calling CRDA to update world regulatory domain
    IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
    cfg80211: Calling CRDA to update world regulatory domain
    IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
    IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
    cfg80211: Calling CRDA to update world regulatory domain
    IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
    IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
    cfg80211: Calling CRDA to update world regulatory domain
    IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
    IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
    cfg80211: Calling CRDA to update world regulatory domain
    IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
    IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
    cfg80211: Calling CRDA to update world regulatory domain
    IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
    IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
    cfg80211: Calling CRDA to update world regulatory domain
    IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready

    A failed connection is likely the result of an improper password. Use wpa_passphrase to make sure you have the right psk for the password.

  7. The ifconfig command will be used to determine that the device is wirelessly connected to the network. Look to see that wlan0 has an IP address.

    wlan0 Link encap:Ethernet HWaddr A8:54:B2:42:89:8D
    inet addr:10.0.4.148 Bcast:10.0.255.255 Mask:255.255.0.0
    UP BROADCAST RUNNING MULTICAST MTU:1500 METRIC:1
    RX packets:3395 errors:0 dropped:6 overruns:0 frame:0
    TX packets:60 errors:0 dropped:0 overruns:0 carrier:0
    collisions:0 txqueuelen:1000
    RX bytes:346619 (338.4 KiB) TX bytes:6318 (6.1 Kib)

  8. Disconnect any physical connections from the system and ping to www.emacinc.com to verify that the system can wirelessly connect to the Internet.

    root@ipac9x25:~# ping -c 3 www.emacinc.com

    PING www.emacinc.com (172.16.0.10): 56 data bytes 64 bytes from 172.16.0.10: seq=0 ttl=63 time=1.910 ms 64 bytes from 172.16.0.10: seq=1 ttl=63 time=1.748 ms 64 bytes from 172.16.0.10: seq=2 ttl=63 time=2.061 ms

    --- www.emacinc.com ping statistics --- 3 packets transmitted, 3 packets received, 0% packet loss round-trip min/avg/max = 1.748/1.906/2.061 ms

    root@ipac9x25:~#


Troubleshooting

If your come across any issues communicating though the network, try these suggestions as starting points to resolve the problem(s).

  • View the /etc/resolv.conf file to view the DNS servers provided from the DHCP server.
  • Inspect the routing table using the route command, as shown here:
root@ipac9x25:~# route -n

Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 10.0.2.1 0.0.0.0 UG 0 0 0 eth0 10.0.0.0 0.0.0.0 255.255.0.0 U 1 0 0 eth0

root@ipac9x25:~#

Conclusion

After connecting to a network the first time, the system will be able to connect to the same network when rebooted or powered on. Connecting to a new network will require going through the procedures set out under the Wireless Networking section to revise the network settings.


This page walked the reader through the procedure to connect a machine to a wireless network via a USB Wifi adapter or built-in wireless, and the process to acquire the necessary software tools to make the connection for the first time. While there are plenty of USB wireless adapters available for sale, we used an adapter intended for use on Linux machines with a driver supported by EMAC OE Linux. Other USB wireless adapters may be used to connect EMAC devices to wireless networks, but they will often face issues with driver support or other compatibility issues. Requests to purchase the adapter should be sent to sales@emacinc.com; please include a reference to the EPN, PER-USB-00005-R, when sending a request to purchase this adapter.


Further Information

Where to Go Next
Pages with Related Content
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