#!/bin/sh
#
# Usage: modhosts [load]

. /bin/env.mod.rcconf

ar7ipaddr () {
	local SEC=$1
	local DEV=$2
	echo $(echo 'ar7cfg.'$SEC'['$DEV'].ipaddr' | ar7cfgctl -s)
}

ar7hostname () {
	HOSTNAME=$(echo servercfg.hostname | ar7cfgctl -s)
	HOSTNAME=$(eval echo $HOSTNAME)
	if [ "$HOSTNAME" != "(none)" ]; then
		echo $HOSTNAME
	else
		echo $CONFIG_HOSTNAME
	fi
}

ismac() {
	echo $1 | egrep -q '^[[:xdigit:]]{2}(:[[:xdigit:]]{2}){5}$' && return 0
}
isip4() {
	echo $1 | egrep -q '^[[:digit:]]{1,3}(\.[[:digit:]]{1,3}){3}$' && return 0
}
isip6() {
	## example 111a:222b:333c:444d:555e:666f:77a7:88b8
	echo $1 | egrep -q '^(([[:xdigit:]]{1,4}):){7}(([[:xdigit:]]{1,4}))$' && return 0

	## example ::333c:444d:555e:666f:77a7:88b8 | ::88b8
	echo $1 | egrep -q '^(:(:([[:xdigit:]]{1,4})){1,6})$' && return 0

	## example 111a:222b:333c:444d:555e:666f:: | 111a::
	echo $1 | egrep -q '^((([[:xdigit:]]{1,4}):){1,6}:)$' && return 0

	## example 111a::333c:444d:555e:666f:77a7:88b8 | 111a::88b8
	echo $1 | egrep -q '^((([[:xdigit:]]{1,4}):)(:([[:xdigit:]]{1,4})){1,6})$' && return 0

	## example 111a:222b::444d:555e:666f:77a7:88b8 | 111a:222b::88b8
	echo $1 | egrep -q '^((([[:xdigit:]]{1,4}):){2}(:([[:xdigit:]]{1,4})){1,5})$' && return 0

	## example 111a:222b:333c::555e:666f:77a7:88b8
	echo $1 | egrep -q '^((([[:xdigit:]]{1,4}):){3}(:([[:xdigit:]]{1,4})){1,4})$' && return 0

	## example 111a:222b:333c:444d::666f:77a7:88b8
	echo $1 | egrep -q '^((([[:xdigit:]]{1,4}):){4}(:([[:xdigit:]]{1,4})){1,3})$' && return 0

	## example 111a:222b:333c:444d:555e::77a7:88b8
	echo $1 | egrep -q '^((([[:xdigit:]]{1,4}):){5}(:([[:xdigit:]]{1,4})){1,2})$' && return 0
}
isip() {
	isip4 $1 && return 0
	isip6 $1 && return 0
}

create_resolv_conf () {
		local __hostname=$1

		local _nameserver=$(cat /tmp/flash/mod.diff 2>/dev/null| sed -nr "s/.* MOD_RESOLV_DNS='(.*)'/\1/p")
		[ -z "$_nameserver" ] && local _nameserver="127.0.0.1"
		echo "nameserver $_nameserver" > /etc/resolv.conf

		local _domain=$(echo $__hostname |cut -d "." -f2-)
		[ -n "$_domain" ] && echo "domain $_domain" >> /etc/resolv.conf

		local _timeout=$(cat /tmp/flash/mod.diff 2>/dev/null| sed -nr "s/.* MOD_RESOLV_TIMEOUT='(.*)'/\1/p")
		[ -n "$_timeout" ] && echo "options timeout:$_timeout" >> /etc/resolv.conf

		local _attempts=$(cat /tmp/flash/mod.diff 2>/dev/null| sed -nr "s/.* MOD_RESOLV_ATTEMPTS='(.*)'/\1/p")
		[ -n "$_attempts" ] && echo "options attempts:$_attempts" >> /etc/resolv.conf
}

case $1 in
	"")
		mvi /tmp/flash/mod/hosts
		$0 load
		;;
	load)
		_hostname=$(ar7hostname)
		hostname $_hostname

		create_resolv_conf $_hostname

		rm -f /var/tmp/hosts
		rm -f /var/tmp/ethers

		touch /var/tmp/hosts
		touch /var/tmp/ethers

		if [ -r /tmp/flash/mod/hosts ]; then
			last=''
			egrep -v '^(#|[[:space:]]*$)' /tmp/flash/mod/hosts | sort -k4 |
			  while read -r ip mac interface host desc; do
				[ -z "$host" -o "$host" = "*" ] && host="pc$(( hnr = hnr + 1))"
				isip $ip && echo -e "${ip}\t${host} $desc" >> /var/tmp/hosts
				[ "$last" == "$host" ] && continue || last="$host"
				ismac $mac && echo -e "${mac}\t${host}" >> /var/tmp/ethers
			done
		fi

		if ! egrep "^127.0.0.1([[:space:]]+[^[:space:]#]+)*[[:space:]]+localhost($|[[:space:]#])" /var/tmp/hosts -q 2>/dev/null; then
			echo -e "127.0.0.1\tlocalhost" >> /var/tmp/hosts
		fi

		ethmode=$(echo 'ar7cfg.ethmode' | ar7cfgctl -s)
		case $ethmode in
			ethmode_bridge)
				devname=lan
				fallback=eth0
				section=brinterfaces
				break
				;;
			ethmode_router)
				devname=eth0
				fallback=lan
				section=ethinterfaces
				break
				;;
			*)
				devname=eth0
				fallback=lan
				section=ethinterfaces
				;;
		esac
		ipaddr=$(ar7ipaddr $section $devname)
		[ -z "$ipaddr" ] && ipaddr=$(ar7ipaddr $section $fallback)
		[ -z "$ipaddr" ] && ipaddr=169.254.1.1
		[ -d /usr/www.nas ] && nas_hostname="fritz.nas\t"
		if ! egrep "^$ipaddr[[:space:]]" /var/tmp/hosts -q 2>/dev/null; then
			echo -e "$ipaddr\tfritz.box\t$nas_hostname$_hostname" >> /var/tmp/hosts
		fi
		;;
	*)
		echo "Usage: $0 [load]" 1>&2
		exit 1
		;;
esac

exit 0