#!/bin/bash
# 
# netconsole 	This loads the netconsole module with the configured parameters.
#
# chkconfig: - 50 50
# description: Initializes network console logging
# config: /etc/sysconfig/netconsole
#
### BEGIN INIT INFO
# Provides:          netconsole
# Required-Start:    $network
# Short-Description: Initializes network console logging
# Description:       Initializes network console logging of kernel messages.
### END INIT INFO

# Copyright 2002 Red Hat, Inc.
#
# Based in part on a shell script by
# Andreas Dilger <adilger@turbolinux.com>  Sep 26, 2001

PATH=/sbin:/usr/sbin:$PATH
RETVAL=0
SERVER_ADDRESS_RESOLUTION=

# Check that networking is up.
. /etc/sysconfig/network

# Source function library.
. /etc/rc.d/init.d/functions

# Default values
LOCALPORT=6666
DEV=

SYSLOGADDR=
SYSLOGPORT=514
SYSLOGMACADDR=

kernel=$(uname -r | cut -d. -f1-2)

usage ()
{
	echo $"Usage: $0 {start|stop|status|restart|condrestart}" 1>&2
	RETVAL=2
}

print_address_info ()
{
	local host=$1
	local route via target

	route=$(LANG=C ip -o route get to $host/32)
	
	[ -z "$DEV" ] && DEV=$(echo $route | sed "s|.* dev \([^ ]*\).*|\1|")
	echo "DEV=$DEV"
	echo "LOCALADDR=$(echo $route | sed "s|.* src \([^ ]*\).*|\1|")"
	if [[ $route == *" via "* ]] ; then
		via=$(echo $route | sed "s|.* via \([^ ]*\).*|\1|")
		target=$via
	else
		target=$host
	fi
	if [ -z "$SYSLOGMACADDR" ]; then
		arp=$(LANG=C /sbin/arping -f -c 1 -I $DEV $target 2>/dev/null | awk '/ reply from .*[.*]/ { print gensub(".* reply from .* \\[(.*)\\].*","\\1","G"); exit }')
		[ -n "$arp" ] && echo "SYSLOGMACADDR=$arp"
	fi	
}	
	
start ()
{
	[ -f /etc/sysconfig/netconsole ] || exit 6
	. /etc/sysconfig/netconsole

	SYSLOGOPTS=
	# syslogd server, if any
	if [ -n "$SYSLOGADDR" ]; then
		# IPv6 regex also covers 4to6, zero-compressed, and link-local addresses with zone-index addresses.
		# It should also cover IPv4-embedded, IPv4-mapped, and IPv4-translated IPv6 addresses.
		# Taken from: http://stackoverflow.com/a/17871737/3481531
		IPv4_regex="^([0-9]{1,3}\.){3}[0-9]{1,3}$"
		IPv6_regex="^(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,7}:|([0-9a-fA-F]{1,4}:){1,6}:[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,5}(:[0-9a-fA-F]{1,4}){1,2}|([0-9a-fA-F]{1,4}:){1,4}(:[0-9a-fA-F]{1,4}){1,3}|([0-9a-fA-F]{1,4}:){1,3}(:[0-9a-fA-F]{1,4}){1,4}|([0-9a-fA-F]{1,4}:){1,2}(:[0-9a-fA-F]{1,4}){1,5}|[0-9a-fA-F]{1,4}:((:[0-9a-fA-F]{1,4}){1,6})|:((:[0-9a-fA-F]{1,4}){1,7}|:)|fe80:(:[0-9a-fA-F]{0,4}){0,4}%[0-9a-zA-Z]{1,}|::(ffff(:0{1,4}){0,1}:){0,1}((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])\.){3,3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])|([0-9a-fA-F]{1,4}:){1,4}:((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])\.){3,3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9]))$"
		if ! [[ "$SYSLOGADDR" =~ $IPv4_regex ]] && ! [[ "$SYSLOGADDR" =~ $IPv6_regex ]]; then
			# Use IPv4 by default:
			SYSLOGADDR="$(LANG=C getent ahostsv4 $SYSLOGADDR 2> /dev/null)"

			# Try IPv6 in case IPv4 resolution has failed:
			if [[ $? -eq 2 ]]; then
				SYSLOGADDR="$(LANG=C getent ahostsv6 $SYSLOGADDR 2> /dev/null)"
			fi

			if [[ $? -ne 0 ]]; then
				echo $"Unable to resolve IP address specified in /etc/sysconfig/netconsole" 1>&2
				exit 6
			fi

			SYSLOGADDR="$(echo "$SYSLOGADDR" | head -1 | cut --delimiter=' ' --fields=1)"
		fi
	fi
	if [ -z "$SYSLOGADDR" ] ; then
		echo $"Server address not specified in /etc/sysconfig/netconsole" 1>&2
		exit 6
	fi
	eval $(print_address_info $SYSLOGADDR)
	
	if [ -z "$SYSLOGMACADDR" ]; then
		echo $"netconsole: can't resolve MAC address of $SYSLOGADDR" 1>&2
		exit 1
	fi

	SYSLOGOPTS="netconsole=$LOCALPORT@$LOCALADDR/$DEV,$SYSLOGPORT@$SYSLOGADDR/$SYSLOGMACADDR "

	/usr/bin/logger -p daemon.info -t netconsole: inserting netconsole module with arguments \
	$SYSLOGOPTS
	if [ -n "$SYSLOGOPTS" ]; then
		action $"Initializing netconsole" modprobe netconsole \
			$SYSLOGOPTS
		[ "$?" != "0" ] && RETVAL=1
	fi
	touch /var/lock/subsys/netconsole
}

stop ()
{
	if /sbin/lsmod | grep netconsole >/dev/null 2>&1 ; then
	    action $"Disabling netconsole" rmmod netconsole;
	    [ "$?" != "0" ] && RETVAL=1
	fi

	rm -f /var/lock/subsys/netconsole
}

status ()
{
	if /sbin/lsmod | grep netconsole >/dev/null 2>&1 ; then
		echo $"netconsole module loaded"
		RETVAL=0
	else
		echo $"netconsole module not loaded"
		RETVAL=3
	fi
}


restart ()
{
	stop
	start
}

condrestart ()
{
	[ -e /var/lock/subsys/netconsole ] && restart
}


case "$1" in
    stop) stop ;;
    status) status ;;
    start|restart|reload|force-reload) restart ;;
    condrestart) condrestart ;;
    *) usage ;;
esac

exit $RETVAL
