Yeastar TG GSM Gateway to RabbitMQ

Intro

This program relays messages between Yeastar TG series and a RabbitMQ server. RabbitMQ is much saner API for when you need to read received messages, since the only native API TG provides to read received messages is a raw telnet socket providing a subset of Asterisk Call Manager AMI commands. Since we need to connect to the socket anyway, SMS send functionality is provided as well.

Detail

Receiving SMS

Program waits for incoming messages on TG gateway. If a SMS message is detected, it is urldecoded and forwarded to the RabbitMQ with selected routing key. This routing key should be bound to a durable queue, otherwise you risk to lose messages if no consumer is connected. SMS messages are published to the queue as json in the following format:

{
  "event":"ReceivedSMS",
  "privilege":"all,smscommand",
  "id":"",
  "gsmspan":"2",
  "sender":"+123456789",
  "recvtime":"2022-11-05 20:33:05",
  "index":"0",
  "total":"1",
  "smsc":"+123400000",
  "content":"Url decoded SMS text"
}

This corresponds to how the raw socket would represent the message

id - id of received SMS (needed to reconstruct multipart SMS)
gsmspan - port on which the SMS was received
index - orded of the message in case of SMS
total - total number of messages in case of SMS
smsc - relaying SMS Center

In case any other message is received (send confirmations, span status, etc...), this message is redirected to a secondary queue as a raw text message. This does not need to be durable.

Sending SMS

Program listens as a RabbitMQ consumer on a specified queue and waits for json message in the following format:

{
  "destination": "+123456789",
  "message": "Text to send, no need to urlencode",
  "id": "123"
}

destination - where to send
message - Raw text of SMS to send
id - can be set to any number or 1-word text, it will be used in the reply on the confirmation queue.

Build

Just use cargo build. No binary distribution is provided for now.

Minimum supported rustc version is 1.65.0

Setup

cp Settings.toml.example Settings.toml and edit the file

General options:

log_level - "Info", "Debug", "Trace" based on verbosity you need
retry_wait_s - time in seconds between reconnects

TG options:

api_url - TG server:port
api_user - your tg user
api_pass - your tg password
api_sms_send_span - which span to use for sending OUT messages

RabbitMQ options:

rabbit_url - connection string in for of "amqp://user:pass@ip:port"
rabbit_exchange - name of fanout exchange where incoming SMS will be published
rabbit_sms_routing_key - routing key for incoming SMS
rabbit_command_routing_key - routing key for incoming commands
rabbit_consumer_tag - identification tag for consumer
rabbit_consumer_queue - queue where outgoins SMS will arrive

You also need to have RabbitMQ server running. Default options are fine, but make sure your queues are properly bound to routing keys.

Todo

In no particular order:

Allow sending and receiving USSD
Better reconnection handling, reconnect to TG or RabbitMQ after disconnect
Keep received messages in memory while TG thread is running but RabbitMQ is not live
provide Dockerfile or systemd service files
Separate TgClient into its own crate for reuse in different projects (maybe provide more AMI functionality)

Reference

Vendor API description:

The project was tested on TG400, but should run with all current lineup - TG100, TG200, TG400, TG800 and TG1600 , as well as other repackaged Asterisk boxes (as long as AMI is exposed)

If you find this useful, I am open to feedback or pull requests

PPFilip/smsgw-tg-amqp