Setting up RapidSMS with Kannel

Kannel is a free and opensource SMS gateway that can be configured for use with RapidSMS. While in-depth Kannel configuration is outside the scope of this documentation, it’s possible to configure Kannel to connect directly to USB or serial GSM modems as well as third party HTTP or SMPP gateways. For more information about the connections Kannel supports (what Kannel calls an “SMS Center” or “SMSC”), see the in-depth Kannel user guide and refer to “Chapter 6. Setting up a SMS Gateway”.

The following guide will help you setup Kannel on Ubuntu to talk to a single GSM modem and RapidSMS installation.

Installing Kannel

A kannel package is included with Ubuntu, so installation is very easy:

sudo apt-get install kannel

By default in Ubuntu, Kannel starts a WAP gateway but does not start the SMS gateway. To change this behavior, first stop Kannel:

sudo service kannel stop

Now, edit /etc/default/kannel and uncomment the line starting with START_SMSBOX. If you won’t be using the WAP gateway (if you don’t know what that is you probably won’t be), you can also disable it by commenting out START_WAPBOX=1. Note: Simply setting START_WAPBOX=0 will not disable it; you must comment out the line:

sudo vim /etc/default/kannel # or use your favorite editor

Finally, start Kannel again (note it will say “Starting WAP gateway” even if it’s only starting the SMS gateway):

sudo service kannel start

You can check that it’s running by looking at ps ax | grep kannel. You should see something like this:

2446 ?        Ss     0:00 /usr/sbin/run_kannel_box --pidfile /var/run/kannel/kannel_bearerbox.pid --no-extra-args /usr/sbin/bearerbox -v 4 -- /etc/kannel/kannel.conf
2447 ?        Sl     0:00 /usr/sbin/bearerbox -v 4 -- /etc/kannel/kannel.conf
2460 ?        Ss     0:00 /usr/sbin/run_kannel_box --pidfile /var/run/kannel/kannel_smsbox.pid --no-extra-args /usr/sbin/smsbox -v 4 -- /etc/kannel/kannel.conf

Setting up the fake SMSC for testing

Kannel includes support for a Fake SMSC which can be useful during setup for testing both Kannel and RapidSMS. The relevant utility is included in the kannel-extras package:

sudo apt-get install kannel-extras

To make things simpler, we’ll first setup Kannel and RapidSMS to work with a Fake SMSC, and then attempt to connect it to a USB modem.

Configuring Kannel for the first time

The easiest way to get Kannel working with RapidSMS is to start with a sample Kannel configuration. To get started, copy and paste the following into /etc/kannel/kannel.conf, replacing everything currently in the file (make a backup first if you’d like):

# CONFIGURATION FOR USING SMS KANNEL WITH RAPIDSMS
#
# For any modifications to this file, see Kannel User Guide
# If that does not help, see Kannel web page (http://www.kannel.org) and
# various online help and mailing list archives
#
# Notes on those who base their configuration on this:
#  1) check security issues! (allowed IPs, passwords and ports)
#  2) groups cannot have empty rows inside them!
#  3) read the user guide
include = "/etc/kannel/modems.conf"
#---------------------------------------------
# CORE
#
# There is only one core group and it sets all basic settings
# of the bearerbox (and system). You should take extra notes on
# configuration variables like 'store-file' (or 'store-dir'),
# 'admin-allow-ip' and 'access.log'
group = core
admin-port = 13000
smsbox-port = 13001
admin-password = CHANGE-ME
status-password = CHANGE-ME
admin-deny-ip = "*.*.*.*"
admin-allow-ip = "127.0.0.1"
box-deny-ip = "*.*.*.*"
box-allow-ip = "127.0.0.1"
log-file = "/var/log/kannel/bearerbox.log"
log-level = 0
#---------------------------------------------
# SMSC CONNECTIONS
#
# SMSC connections are created in bearerbox and they handle SMSC specific
# protocol and message relying. You need these to actually receive and send
# messages to handset, but can use GSM modems as virtual SMSCs
# Here is a sample SMSC for use with the /usr/lib/kannel/test/fakesmsc command
group = smsc
smsc = fake
smsc-id = FAKE
port = 10000
connect-allow-ip = 127.0.0.1
#---------------------------------------------
# SMSBOX SETUP
#
# Smsbox(es) do higher-level SMS handling after they have been received from
# SMS centers by bearerbox, or before they are given to bearerbox for delivery
group = smsbox
bearerbox-host = 127.0.0.1
sendsms-port = 13013
sendsms-chars = "0123456789 +-"
log-file = "/var/log/kannel/smsbox.log"
log-level = 0
access-log = "/var/log/kannel/smsbox-access.log"
reply-couldnotfetch = "Your message could not be processed at this time.  Please try again later. (err=couldnotfetch)"
reply-requestfailed = "Your message could not be processed at this time.  Please try again later. (err=requestfailed)"
reply-couldnotrepresent = "Your message could not be processed at this time.  Please try again later. (err=couldnotrepresent)"
http-request-retry = 3
http-queue-delay = 10
# SEND-SMS USERS
#
# These users are used when Kannel smsbox sendsms interface is used to
# send PUSH sms messages, i.e. calling URL like
# http://kannel.machine:13013/cgi-bin/sendsms?username=tester&password=foobar...
# This is the username and password that RapidSMS uses to deliver SMSes to
# Kannel.  It must also set the 'smsc' variable in the query string, so that
# Kannel knows which SMSC to use to route the message.
group = sendsms-user
username = rapidsms
password = CHANGE-ME
user-deny-ip = "*.*.*.*"
user-allow-ip = "127.0.0.1;"
#---------------------------------------------
# SERVICES
#
# These are 'responses' to sms PULL messages, i.e. messages arriving from
# handsets. The response is based on message content. Only one sms-service is
# applied, using the first one to match.
# The 'ping-kannel' service let's you check to see if Kannel is running,
# even if RapidSMS is offline for some reason.
group = sms-service
keyword = ping-kannel
text = "Kannel is online and responding to messages."
# There should be always a 'default' service. This service is used when no
# other 'sms-service' is applied.  These relay incoming messages from any
# configured SMSCs to the appropriate HTTP backend URLs in RapidSMS.
# By setting 'accepted-smsc', we are assured that messages are routed to
# the appropriate backend in RapidSMS.
group = sms-service
keyword = default
catch-all = yes
accepted-smsc = FAKE
# don't send a reply here (it'll come through sendsms):
max-messages = 0
get-url = http://127.0.0.1:8080/?id=%p&text=%a&charset=%C&coding=%c

You’ll notice the file includes a file called modems.conf at the top. You can copy this file from where Ubuntu installed it as follows:

sudo cp /usr/share/doc/kannel/examples/modems.conf /etc/kannel/

Next, restart Kannel to reload the new configuration:

sudo service kannel restart

When you look at the process list (ps ax | grep kannel), you should see a 4th process for the smsbox now started, like so:

3231 ?        Ss     0:00 /usr/sbin/run_kannel_box --pidfile /var/run/kannel/kannel_bearerbox.pid --no-extra-args /usr/sbin/bearerbox -v 4 -- /etc/kannel/kannel.conf
3232 ?        Sl     0:00 /usr/sbin/bearerbox -v 4 -- /etc/kannel/kannel.conf
3243 ?        Ss     0:00 /usr/sbin/run_kannel_box --pidfile /var/run/kannel/kannel_smsbox.pid --no-extra-args /usr/sbin/smsbox -v 4 -- /etc/kannel/kannel.conf
3245 ?        Sl     0:00 /usr/sbin/smsbox -v 4 -- /etc/kannel/kannel.conf

You can further test that Kannel is running by using the fake SMSC (used only for testing) to use the “ping-kannel” service that we included in the Kannel configuration above:

/usr/lib/kannel/test/fakesmsc -m 1 "123 789 text ping-kannel"

On the last line of the output you should see the message that was sent by the ping-kannel service, e.g.:

INFO: Got message 1: <789 123 text Kannel is online and responding to messages.>

Press Control-C to kill the fakesmsc command and return to the prompt.

Adding a backend for the fake SMSC to RapidSMS

Now that Kannel is installed and configured correctly, adding support for the Kannel backend to your existing RapidSMS project is not difficult. To begin, simply add the following to your existing INSTALLED_BACKENDS configuration in your settings.py file:

INSTALLED_BACKENDS = {
    "message_tester": {
        "ENGINE": "rapidsms.backends.bucket",
    },
    # other backends, if any
    "kannel-fake-smsc" : {
        "ENGINE":  "rapidsms.backends.kannel",
        "host": "127.0.0.1",
        "port": 8080,
        "sendsms_url": "http://127.0.0.1:13013/cgi-bin/sendsms",
        "sendsms_params": {"smsc": "FAKE",
                           "from": "123", # not set automatically by SMSC
                           "username": "rapidsms",
                           "password": "CHANGE-ME"}, # or set in localsettings.py
        "coding": 0,
        "charset": "ascii",
        "encode_errors": "ignore", # strip out unknown (unicode) characters
    },
}

Now, you should be able to run the RapidSMS router:

./manage.py runrouter

And test connection using the echo app in RapidSMS (if installed in your project):

/usr/lib/kannel/test/fakesmsc -m 1 "123 789 text echo hi"

You should see the message get echoed back to you on the last line:

INFO: Got message 1: <123 123 text hi>

Adding support for a GSM Modem SMSC

This section assumes that you’ve already installed, configured, and setup Kannel to use the Fake SMSC as described above. Once you have Kannel and RapidSMS configured, adding support for additional SMSCs (such as a GSM modem) is fairly easy. It also assumes that you already have a GSM modem connected to your computer, and that you know the device location (e.g., /dev/ttyUSB0) of that modem.

Adding the GSM modem to the Kannel configuration

Using the base configuration given above, add the following to the section titled “SMSC CONNECTIONS” in /etc/kannel/kannel.conf, changing the device = /dev/ttyUSB0 line so that it points to the right device:

group = smsc
smsc = at
smsc-id = usb0-modem
my-number = 1234
modemtype = auto
device = /dev/ttyUSB0

Next, add the following sms-service at the end of the file, which will send incoming messages from the modem to RapidSMS via HTTP:

group = sms-service
keyword = default
catch-all = yes
accepted-smsc = usb0-modem
# don't send a reply here (it'll come through sendsms):
max-messages = 0
get-url = http://127.0.0.1:8081/?id=%p&text=%a&charset=%C&coding=%c

Make sure to restart Kannel to reload the configuration:

sudo service kannel restart

Adding a backend for the GSM modem to RapidSMS

Finally, add a second Kannel backend to your settings.py which will setup the necessary router infrastructure to send and receive messages via the USB modem you configured above in Kannel:

INSTALLED_BACKENDS = {
    # ...
    "kannel-usb0-smsc" : {
        "ENGINE":  "rapidsms.backends.kannel",
        "host": "127.0.0.1",
        "port": 8081,
        "sendsms_url": "http://127.0.0.1:13013/cgi-bin/sendsms",
        "sendsms_params": {"smsc": "usb0-modem",
                           "from": "+SIMphonenumber", # not set automatically by SMSC
                           "username": "rapidsms",
                           "password": "CHANGE-ME"}, # or set in localsettings.py
        "coding": 0,
        "charset": "ascii",
        "encode_errors": "ignore", # strip out unknown (unicode) characters
    },
}

Now, the next time you call ./manage.py runrouter, you should see two Kannel backends get created (one for the fake SMSC and one for the GSM modem).

Troubleshooting

For help troubleshooting, please carefully review the relevant log files in /var/log/kannel as well as the output of the ./manage.py runrouter command. For additional help configuring Kannel, review the Kannel user guide or subscribe to the Kannel users mailing list.

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