#!/bin/sh
#
# tinc		tincd VPN setup script
#
# chkconfig: 	2345 46 54
#
# version:	1.0.8
# authors:	Lubomir Bulej <pallas@kadan.cz>
#               Mads Kiilerich <mads@kiilerich.com>
#
# description:	This script parses tinc configuration files for networks given \
#		in /etc/tinc/nets.boot and for each of the networks it sets up \
#		the interface and static routes and starts the tinc daemon.
#
# processname:	tincd

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

# Source networking configuration.
. /etc/sysconfig/network

# Check that networking is up.
[ ${NETWORKING} = "no" ] && exit 0

#############################################################################
# configuration & sanity checks

TINCD=/usr/sbin/tincd
TCONF=/etc/tinc
TPIDS=/var/run
#DEBUG=-dddd

NETSFILE=$TCONF/nets.boot

# Check the daemon
if [ ! -x $TINCD ]; then
    echo "**tinc: $TINCD does not exist or is not executable!" >&2
    exit
fi

# Check if ip-route is installed
if [ ! -f /sbin/ip ]; then
    echo "**tinc: ip-route utilities not installed!" >&2
    exit
fi

# Check the kernel
if ! ip addr &> /dev/null; then
    echo "**tinc: kernel not configured for use with ip-route!" >&2
    exit
fi

# Check the configuration directory
if [ ! -d $TCONF ]; then
    echo "**tinc: configuration directory ($TCONF) not found!" >&2
    exit
fi

# Check nets.boot
if [ ! -f $NETSFILE ]; then
    echo "**tinc: file with list of VPNs to start ($NETSFILE) not found!" >&2
    exit
fi

# Load names of networks to be started
NETS="$(sed -e 's/#.*//; s/[[:space:]]//g; /^$/ d' $NETSFILE)"


##############################################################################
# prefix_to_mask	Converts prefix length to netmask
#			eg. 17 -> 255.255.128.0
# $1 ... prefix

prefix_to_mask () {
    _MSK=""; _len="$1"
    for _dot in "." "." "." " "; do
	if [ ${_len} -ge 8 ]; then 
           _fld=8
	else           
           _fld="${_len}"
	fi
	
	_MSK="${_MSK}$((255 & (255 << (8 - _fld))))${_dot}"
	_len=$((_len - _fld))
    done
    
    echo ${_MSK}
}


##############################################################################
# mask_to_prefix	Converts netmask to prefix length
# 			eg. 255.255.192.0 -> 18		
# $1 ... netmask

mask_to_prefix () {
    _LEN=0; _msk="$1"
    for _tmp in 1 2 3 4; do
        _fld=${_msk%%.*}
	_msk=${_msk#*.}
	
	while [ ${_fld} -ne 0 ]; do
	    _fld=$(((_fld << 1) & 255))
	    _LEN=$((_LEN + 1))
	done
    done
    
    echo ${_LEN}
}


##############################################################################
# vpn_load ()		Loads VPN configuration
# 
# $1 ... VPN to load

vpn_load () {
    CFG="$TCONF/$1/tinc.conf"
    [ -f $CFG ] || { MSG="$CFG does not exist!"; return 1; }
    
    # load TINCD config
    DEV="$(grep -i -e '^[[:space:]]*TapDevice' $CFG | sed 's/[[:space:]]//g; s/^.*=//g')"
    VPN="$(grep -i -e '^[[:space:]]*(MyOwnVPNIP|MyVirtualIP)' -E $CFG | sed 's/[[:space:]]//g; s/^.*=//g')"
    IFM="$(grep -i -e '^[[:space:]]*VPNMask' $CFG | sed 's/[[:space:]]//g; s/^.*=//g')"
    
    # TapDevice syntax validation
    [ -z "$DEV" ] && \
	{ MSG="TapDevice required!"; return 1; }
    [ $(echo $DEV | wc -l) -gt 1 ] && \
	{ MSG="multiple TapDevice entries not allowed!"; return 1; }
    echo $DEV | grep -q -x -E '/dev/tap[[:digit:]]+' ||
	{ MSG="TapDevice should be in form /dev/tapX!"; return 1; }

    # MyOwnVPNIP/MyVirtualIP syntax validation	
    [ -z "$VPN" ] && \
	{ MSG="MyOwnVPNIP/MyVirtualIP required!"; return 1; }
    [ $(echo $VPN | wc -l) -gt 1 ] && \
	{ MSG="multiple MyOwnVPNIP/MyVirtualIP entries not allowed!"; return 1; }
    echo $VPN | grep -q -x -E \
	'([[:digit:]]{1,3}\.){3}[[:digit:]]{1,3}/[[:digit:]]{1,2}' || \
	{ MSG="badly formed MyOwnVPNIP/MyVirtualIP address $VPN!"; return 1; }

    # VPNMask syntax validation	
    [ $(echo $IFM | wc -l) -gt 1 ] && \
	{ MSG="multiple VPNMask entries not allowed!"; return 1; }
	
	                                                                                    
    # device & IP address extraction
    TAP=${DEV##*/}
    NUM=${TAP#tap}
    ADR=${VPN%%/*}
			                                                                                    
    # netmask is calculated from MyVirtualIP netmask prefix length, except when
    # VPNMask is specified, in which case it is used instead of default prefix

    # VPNMask not specified
    if [ -z "$IFM" ]; then
	LEN=${VPN##*/}
	MSK=$(prefix_to_mask $LEN)
	
    # VPNMask is prefix length, convert it to netmask for MSK
    elif echo $IFM | grep -q -x -E '[[:digit:]]{1,2}'; then
	VPN="$ADR/$IFM"
	MSK=$(prefix_to_mask $IFM)
	
    # VPNMask is netmask, convert it to prefix length for VPN
    elif echo $IFM | grep -q -x -E '([[:digit:]]{1,3}\.){3}[[:digit:]]{1,3}'; then
	VPN="$ADR/$(mask_to_prefix $IFM)"
	MSK="$IFM"
	
    else
	MSG="badly formed interface netmask (VPNMask=$IFM)!"
	return 1
    fi	
    

    # Network & broadcast addresses
    BRD=$(ipcalc --broadcast $ADR $MSK | cut -d"=" -f2)
    NET=$(ipcalc --network $ADR $MSK | cut -d"=" -f2)

    # MAC address
    MAC=$(printf "fe:fd:%0.2x:%0.2x:%0.2x:%0.2x" $(echo $ADR | { IFS=. ; read a b c d; echo $a $b $c $d; }))
    
    # debugging 
    # echo >&2
    # echo "VPN $VPN TAP $TAP NUM $NUM MAC $MAC IFM $IFM" >&2
    # echo "ADR $ADR MSK $MSK NET $NET BRD $BRD" >&2
    
    return 0
}


##############################################################################
# vpn_start ()		starts specified VPN
# 
# $1 ... VPN to start

vpn_start () {    
    MSG=""; ERR=""
    vpn_load $1 || return 1
            
    # create device file
    if [ ! -c $DEV ]; then
	[ -e $DEV ] && rm -f $DEV
	mknod --mode=0600 $DEV c 36 $((16 + NUM))
    fi
    
    # load device module
    ERR="$(insmod ethertap -o "ethertap$NUM" unit="$NUM" 2>&1 1> /dev/null)" ||
        { MSG="could not insmod ethertap as unit $NUM!"; return 2; }
    
    # configure the interface
    ERR="$(ip link set $TAP address $MAC 2>&1)" ||
    	{ MSG="could not set address for device $TAP!"; return 3; }
	
    ERR="$(ip link set $TAP up 2>&1)" ||
    	{ MSG="could not bring up device $TAP!"; return 3; }
	
    ERR="$(ip addr add $VPN brd $BRD dev $TAP 2>&1)" ||
    	{ MSG="could not set IP address for device $TAP!"; return 3; }
    
    # start tincd
    $TINCD --net="$1" $DEBUG || \
	{ MSG="could not start daemon for network $1"; return 3; }

    # setup custom static routes
    /etc/sysconfig/network-scripts/ifup-routes $TAP

    return 0
} # vpn_start


##############################################################################
# vpn_stop ()		Stops specified VPN
#
# $1 ... VPN to stop

vpn_stop () {
    MSG=""; ERR=""
    vpn_load $1 || return 1
    
    # kill the tincd daemon
    PID="$TPIDS/tinc.$1.pid"
    if [ -f $PID ]; then
        $TINCD --net="$1" --kill &> /dev/null
        RET=$?
    
        if [ $RET -eq 0 ]; then
	    dly=0
	    while [ $dly -le 5 ]; do
		[ -f $PID ] || break
	        sleep 1; dly=$((dly + 1))
	    done
	fi
	
	# remove stale PID file
	[ -f $PID ] && rm -f $PID
    fi
    
    # bring the interface down
    ip addr flush dev $TAP &> /dev/null
    ip link set $TAP down &> /dev/null
    
    # remove ethertap module
    rmmod "ethertap$NUM" &> /dev/null
    
    return 0
} # vpn_stop


# Check if there is anything to start
if [ ! -z "$1" -a "$1" != "status" -a -z "$NETS" ]; then
    echo "**tinc: no networks found in $NETSFILE!" >&2
    exit
fi


# See how we were called.
case "$1" in
    start)
	for vpn in $NETS; do
            echo -n "Bringing up TINC network $vpn: "
	    vpn_start $vpn && \
		success "startup of network $vpn" || \
		failure "startup of network $vpn"
	    echo
	    
	    if [ ! -z "$MSG" ]; then
	    	[ ! -z "$ERR" ] && echo "$ERR" >&2
		echo "**tinc: $MSG" >&2
	    fi
	done
	
        touch /var/lock/subsys/tinc
        ;;
	
    stop)
	for vpn in $NETS; do
  	    echo -n "Shutting down TINC network $vpn: "
	    vpn_stop $vpn && \
		success "shutdown of network $vpn" || \
		failure "shutdown of network $vpn"
	    echo
	    
	    if [ ! -z "$MSG" ]; then
	    	[ ! -z "$ERR" ] && echo "$ERR" >&2
		echo "**tinc: $MSG" >&2
	    fi
	done
	
	rm -f /var/lock/subsys/tinc
	;;
	
    status)
	echo -n "Configured VPNs: "
	for vpn in $NETS; do
	    PID="$TPIDS/tinc.$vpn.pid"
	    
	    [ -f $PID ] && PID="$(cat $PID)" || PID="-dead-"
	    ps ax | grep "^[[:space:]]*$PID" && STS="OK" || STS="DEAD"
	    echo -n "$vpn:$STS "
	done
	echo	         
	;;	
	
    restart)
        $0 stop
	$0 start
	;;
		
    *)
        echo "Usage: tinc {start|stop|status|restart}"
        exit 1
esac

exit 0