Repeater linking

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I am testing configurations for TARRA, the Teton Amateur Radio Repeater Association in Wyoming.

IRLP and Pi Repeater stuff from W7BU

Mike has this stuff right now. 2022-11-18

  • IRLP kit
  • Raspberry Pi 3B in a transparent case + Elecrow 5" touch screen plugs in directly to a Pi 3.
  • A bunch of 5V wall warts with USB micro connectors
  • Mini USB Keyboard
  • 3x USB Mouse
  • a pre-programmed 32GB SD card from Canakit
  • 7" Composite LCD
  • 2 or so random 12V wall warts with coax connectors
  • 10BT patch cable

Brian has this (on loan)

  • Pi Repeater 2X from ICS controllers which uses SVXLink
  • 1 12V/2.1A wall wart with coax connector
  • Pi Zero W in transparent Vilros case, with several lids including one for a camera
  • A weird bracket thing that might hold a LCD screen

The PI-REPEATER-2X is in the factory sheet metal box containing a PI-REPEATER-2X controller and a RPI 3B with the cabling done to bring out DB connectors. It has a 12->5V DC regulator too. 2022-11 At some point the cheesy little voltage regulator failed and now I have an external 5V/5A Meanwell supply on it.

The puny failed supply was tiny. Not sure what to do to about that, since the replacement is not.

I also have a Meanwell PSD-30A-5 which needs JST connectors, pins are JST SVH 21T-P1.1 and the housings are VHR-3N and VHR-4N

Two radios

I have two Kenwood TM-271A radios and I am looking at what I can do with them.

NiceRF radios

SHARI -- Kits based on a VHF|UHF radio, set up for ASL, basically a hotspot. Based on the NiceRF SA818S.

The Pi 3 version ($65) connects via 2 USB connectors, so it's entirely driven off a serial port via USB. There is also Pi 4 compatible version of this product.

The separate Pi Hat 4 ($80) version plugs into the GPIO connectors I think. It also requires soldering wires to the Pi 4. Ick.

Another SA818S - based thingie https://wb6amt.com/sa-818-carrier-board/ more generic than the SHARI but cheaper

Maker: https://kitsforhams.com/

Review, including a Youtube!! https://qrznow.com/shari-pi-hat-allstar-sa818-radio-module-for-raspberry-pi/


AllStarLink

We evaluated this and decided it's far too complex for this project. Still and all there is a page now All Star Link

Network routing and Wireguard

Goal here is to route our 44 subnet to the repeaters. The repeaters can be on any service provider so we need to accommodate that.

I spent too much time researching ipip and gre tunnels and gave up and came back to Wireguard. There might or might not be firewalls and NAT on some nodes, and certainly that is the case here at home.

Regarding IPIP and GRE though the best doc I have found is https://wiki.buyvm.net/doku.php/ipip_tunnel I got a tunnel running between two VPSs, tarra and w6gkd but I don't need a setup like that.

So Wireguard it is.

Instructions for setting up a Raspberry Pi as a client Wireguard client set up

Install it, 

sudo apt-get install wireguard -y

Instructions and download are available from https://upcloud.com/community/tutorials/get-started-wireguard-vpn/

For the ERX router, https://github.com/WireGuard/wireguard-vyatta-ubnt/wiki/EdgeOS-and-Unifi-Gateway

Test setup

I am using a Pi3 and a VPS for testing right now, using the official image based on Debian.

Violet is the pi3, on my Spectrum broadband behind a Ubiquiti router.

TARRA is the VPS, at VULTR.

/etc/wireguard/wg0.conf is the config at each end

Bring up connection 

wg-quick up wg0

Test connection

Shut down connection 

wg-quick down wg0

Subnets https://www.calculator.net/ip-subnet-calculator.html?cclass=any&csubnet=28&cip=44.127.9.0&ctype=ipv4&printit=0&x=66&y=16

Show me the INPUT rules, verbosely 

iptables -L INPUT -v

"ACCEPT" in this case says, "nothing interesting here", don't log.

On violet, you can log traffic to monitor it, or just use tcpdump 

iptables -F INPUT
iptables -A INPUT -i wg0 -j LOG
iptables -F OUTPUT
iptables -A OUTPUT -i wg0 -j LOG
tail -f /var/log/messages

or 

tcpdump -i wg0 -n


On tarra 

tcpdump -i wg0 -n

# Make packets coming in from the Internet get written to the right subnet
iptables -t nat -A POSTROUTING -o wg0 -j DNAT -d 44.127.9.2

I think wireguard does this automatically 

ip route add 44.127.9.0/28 via 44.127.9.1

Firewall settings

apt-get install tcpdump dnsutils iptables-persistent ipset fail2ban lynx git

I had fail2ban installed already on both machines, which means that iptables was also installed already and could be the whole problem. My iptables skills are rusty.

"iptables -L" shows me that about 100 sites have been ssh banned. It also told me that FORWARD was DROP on w6gkd hmmm. 

iptables -A INPUT -p 4 -j ACCEPT
iptables -A INPUT -p udp --dport 520 -j ACCEPT
iptables -P FORWARD ACCEPT

# Drop various services we don't want running over the tunnel, mostly Microsoft stuff
iptables -A OUTPUT -o tun0 -p udp --dport 10001 -j DROP
iptables -A OUTPUT -o tun0 -p udp --dport 137:139 -j DROP
iptables -A OUTPUT -o tun0 -p udp --dport 5678 -j DROP 
# Drops destination unreachable replies to various probe responses saving bandwidth
iptables -A OUTPUT -o tun0 -p icmp --icmp-type destination-unreachable -j DROP

# This prevents nested ipencap see https://ohiopacket.org/xrpi/docs/ipencap.htm
iptables -t raw -I PREROUTING -p 4 -i tun0 -j DROP
# This prevents a general loop
iptables -I FORWARD -i tun0 -o tun0 -j DROP
# Drops outbound unassigned IPs from looping though tunl0 via ipencap
# You must add accept rules under this line to make exceptions
# Drop traffic that does not have one of our 44 addresses on it.
iptables -I FORWARD ! -s 44.127.9.0/24 -o tunl0 -j DROP

# I don't think this will hurt anything but might no longer matter with current amprd 3.0
iptables -A OUTPUT -o ens3 -p icmp --icmp-type destination-unreachable -m state --state RELATED -j DROP

Tarra server

Scripts are in /etc/wireguard/ to bring up connections including wg-all.sh

Each remote node has its own set of keys in /etc/wireguard/KEYS and its own script, for example, 

cd /etc/wireguard
./wg-rendezvous.sh down
./wg-rendezvous.sh up

Restoring connections after rebooting is handled via systemd.

Run "systemctl start wg-all.service" to bring everything up and "systemctl stop wg-all.service" to stop everything. Check /var/log/daemon.log for messages.

To implement this I created two files, 

cd /lib/systemd/system
cat wg-all.target
[Unit]
Description=WireGuard Tunnels for Tarra

and 

cat wg-all.service 
[Unit]
Description=WireGuard via wg-all for TARRA
After=network-online.target nss-lookup.target
Wants=network-online.target nss-lookup.target
PartOf=wg-all.target

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/etc/wireguard/wg-all.sh up
ExecStop=/etc/wireguard/wg-all.sh down

[Install]
WantedBy=multi-user.target

Monitoring Wireguard

I tried building prometheus-wireguard-exporter for arm64 and gave up, then I found there is a pre-built version on the Docker Hub. 

docker pull mindflavor/prometheus-wireguard-exporter:latest

This works to start it up, and to test it, 

docker run -d --net=host --cap-add=NET_ADMIN --name wgexporter mindflavor/prometheus-wireguard-exporter -a true
curl -s http://localhost:9586/metrics
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