#!/bin/sh
# router-entrypoint.sh
#
# Brings up the simulated br-zt bridge that mirrors production: the
# ZeroTier member interface (here, the container's interface on
# zt-exit-net) is enslaved to br-zt and its IP is moved onto br-zt. This
# makes 'ip route ... dev br-zt' actually reach 10.99.12.0/24.
set -eu

WIBLAN_CIDR="${ZTG_WIBLAN_CIDR:-10.99.13.0/24}"

echo "[entrypoint] bringing up br-zt bridge"

# Find the interface holding 10.99.12.x.
ZT_IFACE=$(ip -o -4 addr show \
	| awk '$4 ~ /^10\.99\.12\./ {print $2; exit}')
if [ -z "$ZT_IFACE" ]; then
	echo "[entrypoint] WARNING: no interface in 10.99.12.0/24; tests will fail" >&2
	ZT_IFACE=eth1
fi
echo "[entrypoint] ZT-side interface: $ZT_IFACE"

ip link add name br-zt type bridge 2>/dev/null || true
ip link set br-zt up

if [ "$ZT_IFACE" != "br-zt" ]; then
	ADDR=$(ip -o -4 addr show dev "$ZT_IFACE" \
		| awk '$4 ~ /^10\.99\.12\./ {print $4; exit}')
	if [ -n "$ADDR" ]; then
		ip addr del "$ADDR" dev "$ZT_IFACE" 2>/dev/null || true
		ip addr add "$ADDR" dev br-zt
	fi
	ip link set "$ZT_IFACE" master br-zt
fi

echo 1 > /proc/sys/net/ipv4/ip_forward
echo 0 > /proc/sys/net/ipv4/conf/all/send_redirects 2>/dev/null || true

# Seed the baseline policy routing the production router boots with.
ip rule del from "$WIBLAN_CIDR" table 100 2>/dev/null || true
ip rule add from "$WIBLAN_CIDR" table 100 priority 100

# Seed the current gateway's host route + table 100 default. These mirror
# what /etc/rc.local installs on boot in production.
ip route replace 10.99.12.3 dev br-zt
ip route replace default via 10.99.12.3 dev br-zt table 100
ip route replace "$WIBLAN_CIDR" dev br-zt table 1

echo "[entrypoint] baseline state:"
ip -o -4 addr show dev br-zt
echo "--- table 100:"
ip route show table 100
echo "--- rule:"
ip rule show

exec "$@"