liminix/modules/cdc-ncm/wwan.nix
2024-05-24 17:23:27 +02:00

47 lines
1.7 KiB
Nix

{
liminix
, usb-modeswitch
, ppp
, lib
, svc
}:
{ apn, username, password, authType }:
let
inherit (liminix.services) oneshot;
authTypeNum = if authType == "pap" then "1" else "2";
chat = lib.escapeShellArgs [
# Your usb modem thing might present as a tty that you run PPP
# over, or as a network device ("ndis" or "ncm"). The latter
# kind is to be preferred, at least in principle, because it's
# faster. This initialization sequence works for the Huawei
# E3372, and took much swearing: the error messages are *awful*
"" "AT"
"OK" "ATZ"
# create PDP context
"OK" "AT+CGDCONT=1,\"IP\",\"${apn}\""
# activate PDP context
"OK" "AT+CGACT=1,1"
# setup username and password per requirements of sim provider.
# (caret is special to chat, so needs escaping in AT commands)
"OK" "AT\\^AUTHDATA=1,${authTypeNum},\"\",\"${password}\",\"${username}\""
# start the thing (I am choosing to read this as "NDIS DialUP")
"OK" "AT\\^NDISDUP=1,1"
];
modemConfig = oneshot {
name = "modem-configure";
# this is currently only going to work if there is one
# modem only plugged in, it is plugged in already at boot,
# and nothing else is providing a USB tty.
# https://stackoverflow.com/questions/5477882/how-to-i-detect-whether-a-tty-belonging-to-a-gsm-3g-modem-is-a-data-or-control-p
up = ''
sleep 2
${usb-modeswitch}/bin/usb_modeswitch -v 12d1 -p 14fe --huawei-new-mode
sleep 5
${ppp}/bin/chat -s -v ${chat} 0<>/dev/ttyUSB0 1>&0
'';
down = "chat -v '' ATZ OK </dev/ttyUSB0 >&0";
};
in svc.network.link.build {
ifname = "wwan0";
dependencies = [ modemConfig ];
}