User's Manual

C External Landing Page API
268 Installation and User Guide: Airgo Access Point
Once redirected to the web server, the user is able to browser only in the walled garden. This
restricted set of web pages should provide a means to login into the network and optionally a means
to obtain an account for first-time users. When a user is successfully authenticated, the ELPS
returns a redirection URL that signals the AP to allow unrestricted access for the specific station (a
Connection Request).
Redirection URL generated by the ELPS:
https://192.168.254.249/Forms/
ExtCmd_html_1?Xnp=www.google.com&Xcmd=crq&Xts=0410280335&Xssid=myHotspot&Xm
ac=00%3Aaf%3A50%3A00%3A00%3A00&Xcv=f4eb6692aeffe839&Xdata=480&Xid=bob
The base portion of the URL was formed using the IP address originally passed to the web server as
the gpm field (AP IP address). The URL is protected from modification, spoofing, or reuse by the
use of a timestamp and a cryptographic check value. The URL must always have the form:
https://<AP IP Address>/Forms/ExtCmd_html_1?<parameters>
The URL that signals the AP to permit access for a particular station uses parameters that are
passed in the URL. These form a connection request. The following parameters are supported:
Upon successful opening of the AP HTTP filter, the user’s browser is redirected back to the web
server. This permits positive indication of user access for billing purposes on the ELPS. The
redirected URL contains the following parameters:
Table 19: Fields in the STA-ELPS-to-AP Connection Request
Field Description
Xcmd The command type (connect for this example) For a connect this value
MUST be 'crq'
Xnp Not used
Xid Optional, the login user id (included in logs)
Xip Optional, not used for the connect command.
Xssid The SSID.
Xmac The MAC address of the station that has been authenticated.
Xdata Command data. For the connect request should contain the duration of the
permitted user connectivity in minutes.
Xts A time stamp of the form yymmddhhMM, where yy=year, mm=month,
dd=day, hh=hours, MM=minutes. To be valid, the time value (in UTC)
must be within plus or minus 5 minutes of the AP’s time.
Xcv A SHA1 hash using the shared password.
Table 20: Fields in the STA-AP-to-ELPS Connection Response
Field Description
Xcmd This MUST be 'crs' for the connection response.
Xnp Not used
Xid Not used.