#!/bin/sh

if [ "$(id -u)" -ne 0 ]; then
	echo "Root required for execution" >&2
	exit 1
fi

# What if we want to clean
if [ "$1" = "clean" ]; then
	kill $(cat /tmp/lxc-dhcpd.pid)
	rm -f /tmp/lxc-dhcpd.pid /tmp/lxc-dhcpd.conf
	ip link del dev vbr0
	exit
fi

# Setup bridge
ip link add name vbr0 type bridge
ip link set vbr0 up
ip addr add 192.168.30.1/24 dev vbr0

# Start dhcp server

# This just takes first dns nameserver configured. Maybe we might want to be
# little bit more clever.
DNS_SERVER=$(cat /etc/resolv.conf |grep -i nameserver|head -n1|cut -d ' ' -f2)
echo "# DHCPD configuration generated by lxc-net script
authoritative;
default-lease-time 600;
max-lease-time 7200;
option subnet-mask 255.255.255.0;
option broadcast-address 192.168.30.255;
option routers 192.168.30.1;
option domain-name-servers $DNS_SERVER;
subnet 192.168.30.0 netmask 255.255.255.0 {
   range 192.168.30.10 192.168.30.100;
}" > /tmp/lxc-dhcpd.conf
dhcpd -4 -pf /tmp/lxc-dhcpd.pid -cf /tmp/lxc-dhcpd.conf vbr0

# Setup network forwarding (TODO add -o ethX to iptable command)
sysctl -w net.ipv4.ip_forward=1
iptables -t nat -A POSTROUTING -j MASQUERADE