Sierra em7565 LTE Modem Linux Guide

wwan-config.service

[Service]
Type=oneshot
ExecStart=/usr/local/sbin/wwan up

[Install]
# replace this with your modems persistent device name!
WantedBy=sys-subsystem-net-devices-wwp0s20f0u6i8.device

wwan.sh

#!/bin/bash

# This script is used to configure a Sierra EM7565 on Linux. This modem uses raw-ip only
# so you can't just use normal DHCP. You have to get the IP information from the modem and
# manually set the linux-side network interface to match. You also have to set the IP mode
# to "raw" every time the interface appears (on boot and after suspend/resume).
#
# You may need to configure udev rules to put your modem in the right mode for the ttyUSB devices
# to show up. On Arch this is accomplished by installing the `usb_modeswitch` package.
#
# Assumptions:
#  - you're using systemd-networkd
#
#  - you have the following modules loaded (/etc/modules-load.d):
#      qmi_wwan
#      pcserial
# 
#  - you've gotten the modem connect successfully at least once, using something like the following:
#      qmicli -d /dev/cdc-wdm1 --device-open-"net=net-raw-ip|net-no-qos-header" --wds-start-network=fast.t-mobile.com --client-no-release-cid
#
#  - you've configured an autoconnect profile, so you don't have to start the modem manually each time:
#      qmicli -d /dev/cdc-wdm1 --wds-create-profile=3gpp,name=t-mobile,apn=fast.tmobile.com,pdp-type=IPV4V6 
#      qmicli -d /dev/cdc-wdm1 --wds-set-autoconnect-settings=enabled
#
#  - you've properly configured the modem using the following AT commands. Note that MBIM does NOT seem to work
#    (tested on Arch Linux, kernel 4.20) with this card, so I disable it via USBCOMP setting below. QMI FTW. Also,
#    for thinkpads you have to disable USB fast enumeration on boot to allow the card to bypass the bios whitelist.
#    This is done with the AT!CUSTOM command below. See https://github.com/danielewood/sierra-wireless-modems for more.
#
#    Enter these commands by accessing the modem's serial console (screen /dev/ttyUSB2). Note that you have to
#    `ip link set down $interface` on your modem first or it will lag out like crazy:
#
#      ATE1
#      AT!ENTERCND="A710"
#      AT!IMPREF="GENERIC"
#      AT!USBCOMP=1,3,0000050D
#      AT!SELRAT=06
#      AT!BAND=00
#      AT!BAND=09
#      AT!CUSTOM="FASTENUMEN",2
#      AT!RESET
#
#  - Once you've put this script somewhere, create and enable a systemd unit file like the following, so it
#    will get executed every time the modem's network device is brought up:
#      $  cat /etc/systemd/system/wwan-config.service                                                                                           ~
#      [Service]
#      Type=oneshot
#      ExecStart=/usr/local/sbin/wwan up
#
#      [Install]
#      # replace this with your modems persistent device name!
#      WantedBy=sys-subsystem-net-devices-wwp0s20f0u6i8.device
#
# This took me multiple sleepless nights to figure out. You're welcome.

DEV=/dev/cdc-wdm1
ROUTE_METRIC=30

IFACE=$(qmicli -d $DEV -w)

die() {
  echo "$@" 1>&2
  exit 1
}

mask2cdr () {
  # Assumes there's no "255." after a non-255 byte in the mask
  local x=${1##*255.}
  set -- 0^^^128^192^224^240^248^252^254^ $(( (${#1} - ${#x})*2 )) ${x%%.*}
  x=${1%%$3*}
  echo $(( $2 + (${#x}/4) ))
}

ifdown() {
  cat > /etc/systemd/network/30-wwan.network << EOF
[Match]
Name=$IFACE

[Link]
Unmanaged=true
EOF
  systemctl restart systemd-networkd
  ip link set "$IFACE" down
}

ifup() {
  ifdown
  eval $(qmicli -d "$DEV" --wds-get-current-settings \
    | tail -n+2 \
    | tr '[:lower:]' '[:upper:]' \
    | sed -e 's/: /=/;s/^\s*//;s/ /_/g')

  IPV4_CIDR=$IPV4_ADDRESS/$(mask2cdr $IPV4_SUBNET_MASK)

  cat > /etc/systemd/network/30-wwan.network << EOF
[Match]
Name=$IFACE

[Link]
MTUBytes=$MTU
Multicast=true
ARP=false

[Network]
Address=$IPV4_CIDR
DNS=$IPV4_PRIMARY_DNS
DNS=$IPV4_SECONDARY_DNS

[Route]
Gateway=$IPV4_GATEWAY_ADDRESS
Metric=$ROUTE_METRIC
EOF
  echo Y > "/sys/class/net/$IFACE/qmi/raw_ip"
  systemctl restart systemd-networkd
}

status() {
  qmicli -d "$DEV" --wds-get-current-settings                                                                                ~
  qmicli -d "$DEV" --wds-get-packet-service-status
  qmicli -d "$DEV" --wds-get-packet-statistics
  qmicli -d "$DEV" --nas-get-signal-info
  qmicli -d "$DEV" --nas-get-serving-system
}	

case $1 in
  up)     ifup ;;
  down)   ifdown ;;
  status) status  ;;
  *)      die "usage: $1 up|down|status" ;;
esac