#!/bin/bash
# Needs bash for printf -v VARNAME
# -----------------------------------------------------------------------------
#
# Copyright (c) 2011..2018 bwLehrpool-Projektteam
#
# This program/file is free software distributed under the GPL version 2.
# See https://www.gnu.org/licenses/old-licenses/gpl-2.0-standalone.html
#
# If you have any feedback please consult https://bwlehrpool.de and
# send your feedback to bwlehrpool@hs-offenburg.de.
#
# General information about bwLehrpool can be found at https://bwlehrpool.de
#
# -----------------------------------------------------------------------------
#
#                               Mini-Linux Toolkit
#
# -----------------------------------------------------------------------------

. /opt/openslx/config

primary="br0"
[ -n "$SLX_BRIDGE" ] && primary="$SLX_BRIDGE"

RESOLV_CONF="/opt/openslx/resolv.conf"
THIS_RESOLV="/run/network/${interface}.resolv"

rebuild_resolv_conf () {
	# Don't do anything if the active resolv.conf is not ours
	# Also this will not run resolvconf update.d... No idea if we should still do so...
	[ -L "/etc/resolv.conf" ] || return 0
	[ "x$(readlink "/etc/resolv.conf")" == "x${RESOLV_CONF}" ] || return 0
	# Maybe make this smarter some time, if anyone is using clients that are on multiple networks at once etc...
	# This is a little braindead but should work most of the time
	sort -u /run/network/*.resolv > "$RESOLV_CONF" 2> /dev/null

	# add support for resolv.conf update scripts // see man(8) resolvconf
	for s in /etc/resolvconf/update.d/*.sh; do
		[ -f "$s" ] && [ -x "$s" ] && "$s"
	done
}

escape_search() {
	echo "$@" | sed -e 's/[]\/()$*.^|[]/\\&/g'
}

escape_replace() {
	echo "$@" | sed -e 's/[\/&]/\\&/g'
}

check_env() {
	if [ -z "$ip" ] || [ -z "$subnet" ] || [ -z "$interface" ]; then
		echo "$1 event with missing data" >&2
		echo "ip = '$ip'" >&2
		echo "subnet = '$subnet'" >&2
		echo "interface = '$interface'" >&2
		exit 1
	fi
}

if [ ! -d /run ]; then
	echo -n "Waiting for /run." >&2
	while [ ! -d /run ]; do
		echo -n "." >&2
		usleep 500000
	done
	echo "" >&2
fi

mkdir -p "/run/network"

case "$1" in
	bound|renew)
		check_env "$1"
		mkdir -p "/run/dhcpc"
		# Set address on interface
		ip addr add "$ip/$(ipcalc -s -p "$ip" "$subnet" | sed s/.*=//)" dev "$interface"
		# Set default route, if given
		if [ -n "$router" ]; then
			ip route add default via "$router"
		fi
		
		# get domain, hostname and thus fqdn from DNS
		dns_fqdn=$(/opt/openslx/bin/busybox timeout -t 3 rdns "$ip")
		dns_short="${dns_fqdn%%.*}"
		# check if it is fqdn
		if [ "$dns_fqdn" == "$dns_short" ]; then
			unset dns_fqdn dns_short
		fi

		# Update resolver configuration file
		conf_file="$(mktemp)"
		# Own domain suffix
		if [ -n "$domain" ]; then
			:
		elif [ -n "$dns_fqdn" ]; then
			domain="${dns_fqdn#*.}"
			
		elif [ -n "$SLX_NET_DOMAIN" ]; then
			domain="$SLX_NET_DOMAIN"
		fi
		if [ -n "$domain" ]; then
			echo "domain ${domain%% *}" >> "${conf_file}"
		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="$domain"
		fi
		# Search domains
		if [ -n "$search" ]; then
			echo "search $search" >> "${conf_file}"
		elif [ -n "$SLX_NET_SEARCH" ]; then
			echo "search $SLX_NET_SEARCH" >> "${conf_file}"
		elif [ -n "$SLX_NET_DOMAIN" ]; then
			echo "search $SLX_NET_DOMAIN" >> "${conf_file}"
		fi
		for i in $dns; do
			echo "$0: Adding DNS $i"
			echo "nameserver $i" >> "${conf_file}"
		done
		
		if [ -x "/sbin/resolvconf" ] && [ -L "/etc/resolv.conf" ] && [ -d "/etc/resolvconf/update.d" ]; then
			# Automatic handling :-)
			resolvconf --create-runtime-directories
			resolvconf --enable-updates
			< "$conf_file"  resolvconf -a "${interface}.udhcpc"
			rm -- "$conf_file"
		else
			# Manual handling required :-(
			mv -f "$conf_file" "$THIS_RESOLV"
			rebuild_resolv_conf
		fi

		
		# Things that should only happen for the main interface that was used for booting
		if [ "$interface" = "$primary" ]; then
			# Update IP
			sed -i "s/^\(SLX_PXE_CLIENT_IP=\).*$/\1'$ip'/" /opt/openslx/config
			# Write DOMAIN and SEARCH to /opt/openslx/config if empty
			if [ -z "$SLX_NET_DOMAIN" ] && [ -n "$domain" ]; then
				sed -i "/^SLX_NET_DOMAIN=/d" /opt/openslx/config
				echo "SLX_NET_DOMAIN='$domain'" >> /opt/openslx/config
			fi
			if [ -z "$SLX_NET_SEARCH" ] && [ -n "$search" ]; then
				sed -i "/^SLX_NET_SEARCH=/d" /opt/openslx/config
				echo "SLX_NET_SEARCH='$search'" >> /opt/openslx/config
			fi
			# Same for WINS servers
			if [ -z "$SLX_NET_WINS" ] && [ -n "$wins" ]; then
				sed -i "/^SLX_NET_WINS=/d" /opt/openslx/config
				echo "SLX_NET_WINS='$wins'" >> /opt/openslx/config
			fi
			
			# Only if network is not ready yet
			if [ ! -e "/run/network/network-ready" ]; then
				# Update hostname
				if [ -z "$dns_fqdn" ] && [ -n "$domain" ] && [ -n "$hostname" ]; then
					# fallback to what the dhcp told us
					dns_fqdn="${hostname}.${domain}"
				fi
				if [ -z "$dns_fqdn" ]; then
					# only if there is no /etc/hostname, we fall back (far back, that is)
					[ ! -s "/etc/hostname" ] && dns_fqdn="slx-client"
				fi
				# finally, if dns_fqdn was set to anything, apply it
				if [ -n "$dns_fqdn" ]; then
					dns_short="${dns_fqdn%%.*}"
					echo "$dns_short" > "/proc/sys/kernel/hostname"
					echo "$dns_short" > "/etc/hostname"
					if grep '^SLX_HOSTNAME=' /opt/openslx/config 2>/dev/null; then
						sed -i "s/^\(SLX_HOSTNAME=\).*$/\1'$dns_short'/" /opt/openslx/config
					else
						echo "# Config written by openslx-dhcp-script (1)" >> /opt/openslx/config
						echo "SLX_HOSTNAME='$dns_short'" >> /opt/openslx/config
					fi
				fi

				# Update /etc/issue for proper spacing
				/opt/openslx/scripts/openslx-create_issue
				touch "/run/network/network-ready"
				# Mark network target as reached
				systemctl start network.target &
			fi # end "network not ready yet"
			# Remove any stray addresses; we expect the primary interface to only have one
			# address supplied via DHCP. We do this after adding the new one, obviously.
			rem_list=$( ip -o addr show "$interface" | awk '{ for (i=1;i<NF;++i) if ($i == "inet") print $(i+1) }' | grep -v "^${ip}/" )
			if [ -n "$rem_list" ]; then
				echo "PRIMARY: Removing $rem_list since we just got assigned $ip"
				echo 1 > "/proc/sys/net/ipv4/conf/$interface/promote_secondaries"
				for addr in $rem_list; do
					ip addr del "$addr" dev "$interface"
					sed -i "/^$(escape_search "${addr%/*}")(\s|$)/d" /etc/hosts
				done
			fi
		fi # end "primary only"
		
		# Hostname in /etc/hosts
		touch "/etc/hosts"
		hostlist=""
		[ -n "$dns_fqdn" ] && hostlist="$dns_fqdn"
		[ -n "$hostname" ] && [ -n "$domain" ] && [ "x${hostname}.${domain}" != "x$dns_fqdn" ] && hostlist="$hostlist ${hostname}.${domain}"
		if [ -n "$hostlist" ]; then
			for host in $hostlist; do
				host_short="${host%%.*}"
				[ "x$host_short" = "x$host" ] && host_short=""
				sed -i -r "s/\s$(escape_search "$host")(\s|$)/ /g" /etc/hosts
				[ -n "$host_short" ] && sed -i -r "s/\s$(escape_search "$host_short")(\s|$)/ /g" /etc/hosts
				if grep -q -E "^$ip\s" /etc/hosts; then
					sed -i "s/^$(escape_search "$ip")\s.*/$(escape_replace "$ip $host $host_short")/g" /etc/hosts
				else
					echo "$ip $host $host_short" >> /etc/hosts
				fi
			done
		fi
		# Get rid of orphaned lines in /etc/hosts
		sed -i -r '/^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+\s*$/d' /etc/hosts
		
		# "dns ready" target
		if [ -n "$dns" ] && [ ! -e "/run/network/dns-ready" ]; then
			touch "/run/network/dns-ready"
			# Write to openslx-config
			echo "# Config written by openslx-dhcp-script (2)" >> /opt/openslx/config
			echo "SLX_DNS='$dns'" >> /opt/openslx/config
			systemctl start network-dns.target &
		fi
		# "default route exists" target
		if [ -n "$router" ] && [ ! -e "/run/network/gateway-ready" ]; then
			touch "/run/network/gateway-ready"
			systemctl start network-gateway.target &
		fi
		
			# Port redirection for printing happens in printergui module (iptables-helper rule)
			####iptables -A INPUT -i br0 -p tcp --dport 515 -j DROP
			####iptables -A INPUT -i br0 -p tcp --dport 5515 -j DROP
			####iptables -t nat -A PREROUTING -s 192.168.0.0/16 -p tcp --dport 515 -j REDIRECT --to-port 5515
	;;
	
	deconfig)
		check_env "$1"
		if [ "$interface" = "$primary" ]; then
			echo "Ignoring deconfig for primary interface"
		else
			echo 1 > "/proc/sys/net/ipv4/conf/$interface/promote_secondaries"
			clientip=${ip%%:*}
			ip addr del "$clientip/$(ipcalc -s -p "$clientip" "$subnet" | sed s/.*=//)" dev "$interface"
			sed -i "/^$(escape_search "$ip")(\s|$)/d" /etc/hosts
		fi
		
		if [ -x /sbin/resolvconf ] && [ -L /etc/resolv.conf ] && [ -d /etc/resolvconf/update.d ]; then
			# Automatic handling :-)
			resolvconf -d "${interface}.udhcpc"
		else
			# Manual handling required :-(
			rm -f -- "$THIS_RESOLV"
			rebuild_resolv_conf
		fi
	;;
	
	leasefail)
		echo "$0: Lease failed: $message" >&2
		
	;;
	
	nak)
		echo "$0: Received a NAK: $message" >&2
		
	;;
	
	*)
		echo "$0: Unknown udhcpc command: $1" >&2
		exit 1
		
	;;
esac

exit 0