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@jennifer/routeros

SMS

File: src/topics/sms.j. Paths: /tool/sms (SMS_PATH), /tool/sms/inbox (SMS_INBOX_PATH), /tool/sms/send (SMS_SEND_COMMAND).

Background

A router with a cellular modem (lte.md) can send and receive text messages. That matters for one reason: SMS leaves when the uplink is what broke. An e-mail alert about a dead WAN never arrives; a text over the modem does. Pair it with netwatch.md or the scheduler.md and the router tells you itself.

Reception is off by default - a router with a SIM keeps nothing that arrives until you turn it on, and you must name the modem port it receives on.

RouterOS can also execute commands sent by SMS. That is why restrictSms exists: allowedNumber is the sender the router will act on, and setting it is the difference between "anyone who learns the SIM number can drive this router" and "only this number can".

Structs

jennifer
mt.SmsSettings { receiveEnabled, port, channel, allowedNumber,
                 keepMaxSms, autoErase }
mt.SmsMessage  { id, phone, message, timestamp, kind }

Functions

FunctionPurpose
smsSettings(c) → SmsSettingsthe current settings
enableSmsReceive(c, port)start storing incoming messages
disableSmsReceive(c)stop storing them (the inbox is kept)
restrictSms(c, allowedNumber, keepMaxSms)the sender to honour, how many to keep
sendSms(c, port, phoneNumber, message)send a message
smsInbox(c) → list of SmsMessagethe received messages
removeSmsMessage(c, id)delete one
clearSmsInbox(c) → intempty the inbox, returns how many went

Example

Alerting from a site whose uplink is the problem:

jennifer
mt.sendSms($c, "lte1", "+441632960123", "gw1: uplink down");

Receive, restrict, and read:

jennifer
mt.enableSmsReceive($c, "lte1");
mt.restrictSms($c, "+441632960123", 50);

for (def m in mt.smsInbox($c)) {
    io.printf("%s  %s: %s\n", $m.timestamp, $m.phone, $m.message);
}
io.printf("cleared %d\n", mt.clearSmsInbox($c));

Pitfalls

  • Reception is off until you enable it, and enabling needs the modem port - lteInterfaces(c) from lte.md lists them (usually lte1).
  • Set allowedNumber if the SIM number is at all guessable. Unrestricted, remote SMS commands are an unauthenticated path onto the router.
  • The inbox fills up. keepMaxSms caps it; nothing prunes on its own unless the router's autoErase is on, so a long-running box wants clearSmsInbox on a schedule.
  • Phone numbers are validated leniently - digits plus + - ( ) and spaces - because national formats vary. It catches a name passed where a number belongs, not a wrong number.
  • A modem that is registered but refusing to send is usually out of credit or barred for premium/roaming SMS; the failure comes back as Error{kind: "mikrotik"} from the modem, not from routeros.