#!/bin/sh

# Copyright (c) 2011 - 2012 Rozhuk Ivan <rozhuk.im@gmail.com>
# All rights reserved.
# 
# Subject to the following obligations and disclaimer of warranty, use and
# redistribution of this software, in source or object code forms, with or
# without modifications are expressly permitted by Whistle Communications;
# provided, however, that:
# 1. Any and all reproductions of the source or object code must include the
#    copyright notice above and the following disclaimer of warranties; and
# 2. No rights are granted, in any manner or form, to use Whistle
#    Communications, Inc. trademarks, including the mark "WHISTLE
#    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
#    such appears in the above copyright notice or in the software.
# 
# THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
# TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
# REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
# INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
# WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
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# SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
# IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
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# WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
# PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
# OF SUCH DAMAGE.
#
# Author: Rozhuk Ivan <rozhuk.im@gmail.com>
#


# This script creates bridge between two network interfaces
# downstream - network with clients
# upstream - network with multicast
# downstream <-IGMP-> upstream
# downstream <-UDP<- upstream
# Only packets with multicast destination mac address are forwarded
# through the bridge and (!) are not passed to network stack

# History
#
# Version: 1.3
# * add '-i' option to tcpdump
#
# Version: 1.2
# + option for send mcast to network stack
#
# Version: 1.1
# * small fixes
#
# Version: 1.0
# * initial release


IF_UPSTREAM="$2"
IF_DOWNSTREAM="$3"
CP_MC_ENABLE="$4"
BR_NAME="${IF_UPSTREAM}-${IF_DOWNSTREAM}-br"
PATTERN_MCAST_IGMP="ether[0] & 1 = 1 and (ether[0:4] != 0xffffffff or ether[4:2] != 0xffff) and ip[9] = 2"
PATTERN_MCAST_IGMP_UDP="ether[0] & 1 = 1 and (ether[0:4] != 0xffffffff or ether[4:2] != 0xffff) and (ip[9] = 17 or ip[9] = 2)"
# allways NOT MATCH
BPFPROG_PASSTROUTH="bpf_prog_len=1 bpf_prog=[ { code=6 jt=0 jf=0 k=0 } ]"




usage_msg()
{
	echo "usage: start|stop upstreamIF downstreamIF [enable]"
	echo "This will create bridge between two interfaces for IGMP, and UDP from upstreamIF to downstreamIF"
}


if [ -z "${IF_UPSTREAM}" -o -z "${IF_DOWNSTREAM}" ]; then
	usage_msg
	return 1
fi
if ! ifconfig "$IF_UPSTREAM" > /dev/null 2>&1 ; then
	usage_msg
	echo "Invalid upstream interface: ${IF_UPSTREAM}"
	return 1
fi
if ! ifconfig "$IF_DOWNSTREAM" > /dev/null 2>&1 ; then
	usage_msg
	echo "Invalid downstream interface: ${IF_DOWNSTREAM}"
	return 1
fi


case "$1" in
start)
	echo "start bridging beetwen ${IF_UPSTREAM} and ${IF_DOWNSTREAM}"

	# load modules
	kldload ng_ether > /dev/null 2>&1
	kldload ng_bpf > /dev/null 2>&1
	kldload ng_hub > /dev/null 2>&1

	BPFPROG_MCAST_IGMP=$( tcpdump -i ${IF_DOWNSTREAM} -s 65535 -ddd ${PATTERN_MCAST_IGMP} | \
		( read len ; \
		echo -n "bpf_prog_len=$len " ; \
		echo -n "bpf_prog=[" ; \
		while read code jt jf k ; do \
		  echo -n " { code=$code jt=$jt jf=$jf k=$k }" ; \
		done ; \
		echo " ]" ) )

	BPFPROG_MCAST_IGMP_UDP=$( tcpdump -i ${IF_UPSTREAM} -s 65535 -ddd ${PATTERN_MCAST_IGMP_UDP} | \
		( read len ; \
		echo -n "bpf_prog_len=$len " ; \
		echo -n "bpf_prog=[" ; \
		while read code jt jf k ; do \
		  echo -n " { code=$code jt=$jt jf=$jf k=$k }" ; \
		done ; \
		echo " ]" ) )

	# create and connect nodes
	ngctl mkpeer ${IF_UPSTREAM}: bpf lower ${IF_UPSTREAM}-lower
	ngctl name ${IF_UPSTREAM}:lower ${BR_NAME}-bpf
	ngctl connect ${IF_UPSTREAM}: ${BR_NAME}-bpf: upper ${IF_UPSTREAM}-upper
	ngctl connect ${IF_DOWNSTREAM}: ${BR_NAME}-bpf: lower ${IF_DOWNSTREAM}-lower
	ngctl connect ${IF_DOWNSTREAM}: ${BR_NAME}-bpf: upper ${IF_DOWNSTREAM}-upper
	if [ -n "$CP_MC_ENABLE" ]; then
		ngctl mkpeer ${BR_NAME}-bpf: hub ${IF_UPSTREAM}-h0 h0
		ngctl connect ${BR_NAME}-bpf: ${BR_NAME}-bpf:${IF_UPSTREAM}-h0 ${IF_UPSTREAM}-h1 h1
		ngctl connect ${BR_NAME}-bpf: ${BR_NAME}-bpf:${IF_UPSTREAM}-h0 ${IF_UPSTREAM}-h2 h2
		
		ngctl mkpeer ${BR_NAME}-bpf: hub ${IF_DOWNSTREAM}-h0 h0
		ngctl connect ${BR_NAME}-bpf: ${BR_NAME}-bpf:${IF_DOWNSTREAM}-h0 ${IF_DOWNSTREAM}-h1 h1
		ngctl connect ${BR_NAME}-bpf: ${BR_NAME}-bpf:${IF_DOWNSTREAM}-h0 ${IF_DOWNSTREAM}-h2 h2
	fi
	

	# configure BPF node
	ngctl msg ${BR_NAME}-bpf: setprogram { thisHook=\"${IF_UPSTREAM}-upper\" ifMatch=\"\" ifNotMatch=\"${IF_UPSTREAM}-lower\" ${BPFPROG_PASSTROUTH} }
	ngctl msg ${BR_NAME}-bpf: setprogram { thisHook=\"${IF_DOWNSTREAM}-upper\" ifMatch=\"\" ifNotMatch=\"${IF_DOWNSTREAM}-lower\" ${BPFPROG_PASSTROUTH} }
	if [ -z "$CP_MC_ENABLE" ]; then
		ngctl msg ${BR_NAME}-bpf: setprogram { thisHook=\"${IF_UPSTREAM}-lower\" ifMatch=\"${IF_DOWNSTREAM}-lower\" ifNotMatch=\"${IF_UPSTREAM}-upper\" ${BPFPROG_MCAST_IGMP_UDP} }
		ngctl msg ${BR_NAME}-bpf: setprogram { thisHook=\"${IF_DOWNSTREAM}-lower\" ifMatch=\"${IF_UPSTREAM}-lower\" ifNotMatch=\"${IF_DOWNSTREAM}-upper\" ${BPFPROG_MCAST_IGMP} }
	else
		ngctl msg ${BR_NAME}-bpf: setprogram { thisHook=\"${IF_UPSTREAM}-lower\" ifMatch=\"${IF_UPSTREAM}-h0\" ifNotMatch=\"${IF_UPSTREAM}-upper\" ${BPFPROG_MCAST_IGMP_UDP} }
		ngctl msg ${BR_NAME}-bpf: setprogram { thisHook=\"${IF_UPSTREAM}-h1\" ifMatch=\"\" ifNotMatch=\"${IF_UPSTREAM}-upper\" ${BPFPROG_PASSTROUTH} }
		ngctl msg ${BR_NAME}-bpf: setprogram { thisHook=\"${IF_UPSTREAM}-h2\" ifMatch=\"\" ifNotMatch=\"${IF_DOWNSTREAM}-lower\" ${BPFPROG_PASSTROUTH} }

		ngctl msg ${BR_NAME}-bpf: setprogram { thisHook=\"${IF_DOWNSTREAM}-lower\" ifMatch=\"${IF_DOWNSTREAM}-h0\" ifNotMatch=\"${IF_DOWNSTREAM}-upper\" ${BPFPROG_MCAST_IGMP} }
		ngctl msg ${BR_NAME}-bpf: setprogram { thisHook=\"${IF_DOWNSTREAM}-h1\" ifMatch=\"\" ifNotMatch=\"${IF_DOWNSTREAM}-upper\" ${BPFPROG_PASSTROUTH} }
		ngctl msg ${BR_NAME}-bpf: setprogram { thisHook=\"${IF_DOWNSTREAM}-h2\" ifMatch=\"\" ifNotMatch=\"${IF_UPSTREAM}-lower\" ${BPFPROG_PASSTROUTH} }
	fi

	# configure net if
	ngctl msg ${IF_UPSTREAM}: setautosrc 1
	ngctl msg ${IF_UPSTREAM}: setpromisc 1
	#ngctl msg ${IF_DOWNSTREAM}: setautosrc 0
	ngctl msg ${IF_DOWNSTREAM}: setpromisc 1
	;;
stop)
	echo "stop bridging beetwen ${IF_UPSTREAM} and ${IF_DOWNSTREAM}"

	# configure net if
	ngctl msg ${IF_UPSTREAM}: setautosrc 0
	ngctl msg ${IF_UPSTREAM}: setpromisc 0
	#ngctl msg ${IF_DOWNSTREAM}: setautosrc 0
	ngctl msg ${IF_DOWNSTREAM}: setpromisc 0

	# remove hooks and nodes
	ngctl rmhook ${IF_UPSTREAM}: lower
	ngctl rmhook ${IF_UPSTREAM}: upper
	ngctl rmhook ${IF_DOWNSTREAM}: lower
	ngctl rmhook ${IF_DOWNSTREAM}: upper
	ngctl shutdown ${BR_NAME}-bpf:

	# unload modules
	#kldunload ng_hub > /dev/null 2>&1
	#kldunload ng_bpf > /dev/null 2>&1
	#kldunload ng_ether > /dev/null 2>&1
	;;
*)
	usage_msg
esac


return 0