🦇 B.A.T.M.A.N. Advanced Setup for NeXuS¶

What is B.A.T.M.A.N.?¶

Better Approach To Mobile Adhoc Networking - Layer 2 mesh protocol (like a smart switch) - Auto-routing, self-healing network - Works over WiFi, Ethernet, VPN tunnels - Complements Yggdrasil (overlay) and Reticulum (crypto mesh)

NeXuS Mesh Trinity¶

B.A.T.M.A.N. → Layer 2 mesh (WiFi/Ethernet physical networks)
    ↓
Yggdrasil   → Layer 3 overlay mesh (200::/7 IPv6 global)
    ↓
Reticulum   → Cryptographic mesh (packet radio, LoRa, etc)

Prerequisites¶

Host system needs:

# Load batman-adv kernel module on HOST (not in container)
doas modprobe batman-adv

# Check if loaded
lsmod | grep batman

# Make it load on boot
echo "batman-adv" | doas tee -a /etc/modules-load.d/batman.conf

Build & Start¶

# 1. Build B.A.T.M.A.N. container
podman build -f Dockerfile.batman -t localhost/nexus-batman:latest .

# 2. Apply IPv6 rules (allow B.A.T.M.A.N. link-local)
doas ./nexus-ipv6-yggdrasil-only.sh

# 3. Start NeXuS with B.A.T.M.A.N.
./nexus-shutdown.sh
./nexus-launch-gentle.sh

Configuration¶

Default settings (in batman-setup.sh): - Routing algorithm: BATMAN_V (fastest, most efficient) - Gateway mode: client (use mesh for internet) - Hop penalty: 30 (lower = prefer this node) - Originator interval: 5000ms (announce every 5 seconds) - Bridge loop avoidance: enabled - Distributed ARP table: enabled - Multicast optimization: enabled

To change:

# Edit batman-setup.sh and adjust batctl commands
nano batman-setup.sh

Add Network Interfaces to Mesh¶

B.A.T.M.A.N. needs physical interfaces to mesh over:

# Get into batman container
podman exec -it nexus-batman sh

# Add WiFi interface to mesh
batctl if add wlan0

# Add Ethernet interface
batctl if add eth0

# Add VPN tunnel
batctl if add tun0

# Check added interfaces
batctl if

Monitor Mesh Network¶

# Check neighbors (other mesh nodes)
podman exec nexus-batman batctl n

# Check originators (all nodes in mesh)
podman exec nexus-batman batctl o

# Show gateway servers
podman exec nexus-batman batctl gwl

# Show translation table (who's where)
podman exec nexus-batman batctl tg

# Live kernel log
podman exec nexus-batman batctl log

Use Cases¶

Local mesh WiFi:

# Create mesh between laptops/phones over WiFi
# Each device runs NeXuS + B.A.T.M.A.N.
# Auto-routing, no internet needed

Community mesh network:

# Connect neighborhood over rooftop WiFi links
# B.A.T.M.A.N. handles routing
# Yggdrasil provides global addressing
# Everyone shares internet connection

Disaster recovery:

# When internet is down:
# 1. B.A.T.M.A.N. creates local mesh
# 2. Reticulum adds LoRa/packet radio
# 3. Yggdrasil provides addressing
# = Complete off-grid network!

IPv6 Configuration¶

Allowed ranges: - fe80::/10 - B.A.T.M.A.N. link-local (mesh coordination) - 200::/7 - Yggdrasil global addresses (overlay) - All other IPv6 BLOCKED (prevents leaks)

Check IPv6 rules:

doas ip6tables -L -v -n

Troubleshooting¶

No neighbors showing: - Check if batman-adv module loaded: lsmod | grep batman - Check if interfaces added: batctl if - Check WiFi is in ad-hoc/mesh mode: iwconfig

Container won't start: - Ensure privileged: true in compose file - Check kernel module on HOST: doas modprobe batman-adv - Check container logs: podman logs nexus-batman

Mesh not routing: - Check gateway mode: batctl gw_mode - Check routing algorithm: batctl ra - Increase log level: batctl loglevel all

Advanced: WiFi Mesh Setup¶

Create ad-hoc WiFi network for B.A.T.M.A.N.:

# On HOST (not in container):

# Set WiFi to ad-hoc mode
doas ip link set wlan0 down
doas iw wlan0 set type ibss
doas ip link set wlan0 up

# Join ad-hoc network
doas iw wlan0 ibss join NeXuS-Mesh 2412

# Add to batman mesh
podman exec nexus-batman batctl if add wlan0

# Check neighbors
podman exec nexus-batman batctl n

Integration with Other Mesh Networks¶

With Yggdrasil:

# B.A.T.M.A.N. creates physical layer
# Yggdrasil runs on top for global routing
# Both can coexist on bat0 interface

With Reticulum:

# Reticulum can use bat0 as an interface
# Add to reticulum config:
# [[interfaces]]
#   type = AutoInterface
#   interface_name = bat0

Resources¶

B.A.T.M.A.N. Advanced: https://www.open-mesh.org/
Documentation: https://www.open-mesh.org/projects/batman-adv/wiki
Mailing list: https://lists.open-mesh.org/

🦇 Together Everyone Achieves More - Mesh Edition! 🌀