Create a hotspot with wifi->wifi with fallback to LTE

For my usecase I wanted to create a hotspot for all my IOT devices, have "VaneyVanson" available from everywhere to my phone and wanted to use my home network when I parked outside my home.

Pre-requirements

install

hat

other stuff

Setup Wifi to Wifi hotspot

I didn't want to add a Wifi dongle to my setup and wanted the integrated wifi module on the raspberry to both act as a client and as an Access point, this complicates things but is duable.

1.

sudo apt-get update

sudo apt-get upgrade

2. Edit /etc/dhcpcd.conf

sudo nano /etc/dhcpcd.conf

Insert the below into the bottom of the file:

interface uap0

static ip_address=192.168.70.1/24

nohook wpa_supplicant

3. Backup /etc/dnsmasq.conf

sudo mv /etc/dnsmasq.conf /etc/dnsmasq.conf.orig

4. Create a new /etc/dnsmasq.conf

sudo nano /etc/dnsmasq.conf

interface=lo,uap0 #Use interfaces lo and uap0

bind-interfaces #Bind to the interfaces

server=8.8.8.8 #Forward DNS requests to Google DNS

domain-needed #Don't forward short names

bogus-priv #Never forward addresses in the non-routed address spaces

# Assign IP addresses between 192.168.70.50 and 192.168.70.150 with a 12-hour lease time

dhcp-range=192.168.70.2,192.168.70.150,12h

4. Create file /etc/hostapd/hostapd.conf and add the following

change the channel to your current channel, you can see the current channel with:

# Set the channel (frequency) of the host access point

channel=1

# Set the SSID broadcast by your access point (replace with your own, of course)

ssid=yourSSIDhere

# This sets the passphrase for your access point (again, use your own)

wpa_passphrase=passwordBetween8and64charactersLong

# This is the name of the WiFi interface we configured above

interface=uap0

# Use the 2.4GHz band (I think you can use in ag mode to get the 5GHz band as well, but I have not tested this yet)

hw_mode=g

# Accept all MAC addresses

macaddr_acl=0

# Use WPA authentication

auth_algs=1

# Require clients to know the network name

ignore_broadcast_ssid=0

# Use WPA2

wpa=2

# Use a pre-shared key

wpa_key_mgmt=WPA-PSK

wpa_pairwise=TKIP

rsn_pairwise=CCMP

driver=nl80211

# I commented out the lines below in my implementation, but I kept them here for reference.

# Enable WMM

#wmm_enabled=1

# Enable 40MHz channels with 20ns guard interval

#ht_capab=[HT40][SHORT-GI-20][DSSS_CCK-40]

5. Edit file /etc/default/hostapd and add the following over the #DAEMON_CONF line:

DAEMON_CONF="/etc/hostapd/hostapd.conf"

6. Create a startup script

#!/bin/bash

# Redundant stops to make sure services are not running

echo "Stopping network services (if running)..."

systemctl stop hostapd.service

systemctl stop dnsmasq.service

systemctl stop dhcpcd.service

#Make sure no uap0 interface exists (this generates an error; we could probably use an if statement to check if it exists first)

echo "Removing uap0 interface..."

iw dev uap0 del

#Add uap0 interface (this is dependent on the wireless interface being called wlan0, which it may not be in Stretch)

echo "Adding uap0 interface..."

iw dev wlan0 interface add uap0 type __ap

#Modify iptables (these can probably be saved using iptables-persistent if desired)

echo "IPV4 forwarding: setting..."

sysctl net.ipv4.ip_forward=1

echo "Editing IP tables..."

iptables -t nat -A POSTROUTING -s 192.168.70.0/24 ! -d 192.168.70.0/24 -j MASQUERADE

# Bring up uap0 interface. Commented out line may be a possible alternative to using dhcpcd.conf to set up the IP address.

#ifconfig uap0 192.168.70.1 netmask 255.255.255.0 broadcast 192.168.70.255

ifconfig uap0 up

# Start hostapd. 10-second sleep avoids some race condition, apparently. It may not need to be that long. (?)

echo "Starting hostapd service..."

systemctl start hostapd.service

sleep 10

#Start dhcpcd. Again, a 5-second sleep

echo "Starting dhcpcd service..."

systemctl start dhcpcd.service

sleep 5

echo "Starting dnsmasq service..."

systemctl start dnsmasq.service

echo "wifistart DONE"

7. Edit rc.local system script

Add the following to your /etc/rc.local script above the exit 0 line (note the spacing between "/bin/bash" and "/usr/local/bin/wifistart"):

/bin/bash /usr/local/bin/wifistart

8. Disable the network services:

(you'll lose internet doing this part so best do it locally)

sudo systemctl stop hostapd

sudo systemctl stop dnsmasq

sudo systemctl stop dhcpcd

sudo systemctl disable hostapd

sudo systemctl disable dnsmasq

sudo systemctl disable dhcpcd

9. Reboot and enjoy

sudo reboot

Setup LTE Hat with qmi

1. Prepare LTE HAT

2. If you're using Raspbian Bullseye

disable modemmanager

3. Create a startup script

#!/bin/bash

#make sure module is ready

qmicli -p -d /dev/cdc-wdm0 --dms-set-operating-mode='online'

#configure interface for raw ip protocol

ip link set wwan0 down

echo 'Y' | tee /sys/class/net/wwan0/qmi/raw_ip

ip link set wwan0 up

#connect

qmicli -p -d /dev/cdc-wdm0 --wds-start-network="apn='internet',ip-type=4" --client-no-release-cid

#configure ip address and route

udhcpc -q -f -n -i wwan0

ip li set mtu 1400 dev wwan0

ifmetric wlan0 300

ifmetric wwan0 500

4. Edit rc.local system script

Add the following to your /etc/rc.local script above the exit 0 line (note the spacing between "/bin/bash" and "/usr/local/bin/qmi_reconnect.sh"):

/bin/bash /usr/local/bin/qmi_reconnect.sh

Troubleshooting

Access point trouble shooting

-

-

-

LTE HAT troubleshooting

-

-

-

Credits

-https://forums.raspberrypi.com/viewtopic.php?t=211542 inspiration for access point setup