#!/bin/bash
#
# This script is triggered by udhcpc in stage3 and handle the
# DHCP information given as parameters

{
# for debugging
set -x
NETWORK_CONF="/run/openslx/network.conf"
. "$NETWORK_CONF"

MAIN_NETIF="$SLX_PXE_NETIF"
[ -n "$SLX_VLAN_ID" ] && MAIN_NETIF="${SLX_PXE_NETIF}.${SLX_VLAN_ID}"
[ -n "$SLX_BRIDGE" ]  && MAIN_NETIF="$SLX_BRIDGE"
readonly MAIN_NETIF

if [ "x$1" != "xbound" -a "x$1" != "xrenew" ] \
	|| [ "x$interface" != "x${MAIN_NETIF}" ] \
	|| [ -z "$ip" ]; then
	exit 0
fi

##
## CORE NETWORK CONFIGURATION
##
## > IP, subnet, route

# If we already got an IP from KCL, see if it differs, and remove first if so
# We just try to prevent everything from breaking if the DHCP server doesn't
# objey the renew request by the client and hands out a new address
if [ -n "$SLX_PXE_CLIENT_IP" ]; then
	#...some address is already configured...
	if [ "x${SLX_PXE_CLIENT_IP}" != "x${ip}" ]; then
		#...it's a different one, reconfigure...
		echo "..reconfiguring ${SLX_PXE_CLIENT_IP} to ${ip}.."
		# remove default route and let it be added again below, as it might get lost when changing the primary address on the interface
		ip route del default 2>/dev/null
		ip addr del "$SLX_PXE_CLIENT_IP" dev "${interface}" 2>/dev/null
		ip addr add "${ip}/$(ipcalc -s -p "${ip}" "${subnet}" | sed s/.*=//)" dev "${interface}"
	fi
else
	#...no address configured yet, just add...
	echo "..adding ${ip}.."
	ip addr add "${ip}/$(ipcalc -s -p "${ip}" "${subnet}" | sed s/.*=//)" dev "${interface}"
fi
echo "SLX_DHCP_CLIENT_IP='$ip'" >> "$NETWORK_CONF"

# Same procedure for default gateway
if [ -n "${router}" ]; then
	if [ -s "$SLX_PXE_GATEWAY" ]; then
		if [ "x${SLX_PXE_GATEWAY}" != "x${router}" ]; then
			echo "..reconfiguring default gw from ${SLX_PXE_GATEWAY} to ${router}.."
			ip route replace default via "$router"
		fi
	else
		ip route add default via "$router"
	fi
	echo "SLX_DHCP_GATEWAY='$router'" >> "$NETWORK_CONF"
fi

##
## ADDITIONAL NETWORK CONFIGURATION
##
## > DNS, domain, hostname

rm -f -- "/etc/resolv.conf"

# DNS/domain?
if [ -n "$dns" ]; then
	echo "..got DNS.."
	echo "# From DHCP in stage 3.1" >> "$NETWORK_CONF"
	echo "SLX_DNS='$dns'" >> "$NETWORK_CONF"
fi
for srv in $dns; do
	echo "nameserver $srv" >> "/etc/resolv.conf"
done
if [ -z "$domain" ]; then
	# try to get domain via reverse lookup if empty
	echo "..trying to get domain via DNS, as DHCP didn't supply one.."
	fqdn=$(timeout -t 3 nslookup "$ip" | grep -E "^Address +[0-9]+: +$ip " | head -n 1 | awk '{print $4}')
	domain="${fqdn#*.}"
fi
# Add domain to list of search domains if not in there yet
if [ -n "$domain" ] && [ -n "$search" ]; then
	FOUND=no
	for sd in $search; do
		[ "x$sd" = "x$domain" ] && FOUND=yes
	done
	[ "$FOUND" = "no" ] && search="$domain $search"
elif [ -n "$domain" ]; then
	search="$domain"
fi
# Write out
if [ -n "$domain" ]; then
	echo "domain $domain" >> "/etc/resolv.conf"
	echo "SLX_NET_DOMAIN='$domain'" >> "/run/openslx/network.conf"
fi
if [ -n "$search" ]; then
	echo "search $search" >> "/etc/resolv.conf"
	echo "SLX_NET_SEARCH='$search'" >> "/run/openslx/network.conf"
fi

if [ -n "$ntpsrv" ]; then
	echo "SLX_DHCP_NTP='$ntpsrv'" >> "/run/openslx/network.conf"
fi

# Hostname
# Ignore hostname/fqdn it if hostname was forced per KCL.
if [ -n "$SLX_PXE_HOSTNAME" ]; then
	echo "Hostname set via KCL, ignoring DHCP hostname: '$hostname'"
	hostname="$SLX_PXE_HOSTNAME"
else
	if [ -z "$hostname" ]; then
		# as with domain, if there's no hostname, try to get via DNS
		echo "..trying to get hostname via DNS, as DHCP didn't supply one.."
		[ -z "$fqdn" ] && fqdn=$(timeout -t 3 nslookup "$ip" | grep -E "^Address +[0-9]+: +$ip " | head -n 1 | awk '{print $4}')
		hostname="${fqdn%%.*}"
	elif [ -n "$domain" ]; then
		fqdn="${hostname}.${domain%% *}" # in case domain is a list
	fi
fi

if [ -z "$hostname" ]; then
	# no fallback hostname from DNS, use IP address
	hostname="${ip//./-}"
fi

if [ -n "$hostname" ]; then
	[ -z "$fqdn" ] && fqdn="$hostname"
	echo "..setting hostname $hostname (fqdn: $fqdn).."
	echo "$hostname" > "/proc/sys/kernel/hostname"
	echo "$hostname" > "/etc/hostname"
	echo "127.0.0.1 localhost" > "/etc/hosts"
	echo "127.0.1.1 $fqdn $hostname" >> "/etc/hosts"
	echo "SLX_HOSTNAME='$hostname'" >> "/run/openslx/network.conf"
fi

touch /.network
set +x
} &>> "/run/openslx/initramfs-udhcpc.log.$$"