#!/bin/sh
# This script sets up an Ethernet bridging network across multiple
# Ethernet interfaces using the ng_bridge(4) and ng_ether(4) netgraph
# node types.
#
# To use this script:
#
# 0. Make your own copy of this example script.
#
# 1. Give your bridging network a name by editing the definition of
#    ${BRIDGE_NAME} below. It must be a valid netgraph node name.
#
# 2. Edit the definitions of ${BRIDGE_IFACES} and ${LOCAL_IFACES}
#    as described below to define your bridging interfaces.
#
# 3. Run this script with "start" as the command line argument.
#
# 4. Examine bridging statistics by running this script with "stats"
#    as the command line argument.
#
# 5. Stop bridging by running this script with "stop" as the
#    command line argument.
#
# To run multiple independent bridging networks, create multiple
# copies of this script with different variable definitions.
#
# To make a "brouted" network, with IP being routed and other protocols being
# bridged, add all the interface in the BRIDGE_IFACES to the LOCAL_IFACES.
# If you just want a normal bridge, just one will be enough.
# In some cases you may want some combination.
#

# Give each bridging network a unique name here.

BRIDGE_NAME="bnet0"

# List the names of the interfaces that you want to bridge across
# here in ${BRIDGE_IFACES}. If you want to include the local host
# machine as well then set ${LOCAL_IFACES} as well (they may also be
# listed in ${BRIDGE_IFACES}). Of course, any ${LOCAL_IFACE} must
# be ifconfig(8)ured separately. If you don't want a ${LOCAL_IFACE}
# then assign it the empty string.

BRIDGE_IFACES="de0 fxp0 fxp1"
LOCAL_IFACES="fxp0 fxp1"

#####################################################################
#### Everything below this point should not need to be modified. ####
#####################################################################

# Routine to verify node's existence.
bridge_verify() {
	ngctl info ${BRIDGE_NAME}: >/dev/null 2>&1
	if [ $? -ne 0 ]; then
		echo "${BRIDGE_NAME}: bridge network not found"
		exit 1
	fi
}

# Routine to get and display link stats.
bridge_linkstats() {
	STATS=`ngctl msg ${BRIDGE_NAME}: getstats $1`
	if [ $? -ne 0 ]; then
		exit 1
	fi
	echo "${STATS}" | fmt 2 | awk '/=/ { fl=index($0, "="); \
	    printf "%20s = %s\n", substr($0, 0, fl - 1), substr($0, fl + 1); }'
}

# Start/restart routine.
bridge_start() {

	# Load netgraph KLD's as necessary.
	for KLD in ng_ether ng_bridge; do
		if ! kldstat -v | grep -qw ${KLD}; then
			echo -n "Loading ${KLD}.ko... "
			kldload ${KLD} || exit 1
			echo "done"
		fi
	done

	# Reset all interfaces.
	bridge_stop

	# Verify all interfaces exist.
	for ETHER in ${BRIDGE_IFACES} ${LOCAL_IFACES}; do
		if ! ngctl info ${ETHER}: >/dev/null 2>&1; then
			echo "Error: interface ${ETHER} does not exist"
			exit 1
		fi
		ifconfig ${ETHER} up || exit 1
	done

	# Create new ng_bridge(4) node, attached to the first interface.
	FIRSTIF=`echo ${BRIDGE_IFACES} | awk '{ print $1 }'`
	ngctl mkpeer ${FIRSTIF}: bridge lower link0 || exit 1
	ngctl name ${FIRSTIF}:lower ${BRIDGE_NAME} || exit 1

	# Attach other interfaces as well.
	LINKNUM=0
	for ETHER in ${BRIDGE_IFACES}; do
		if [ ${LINKNUM} != 0 ]; then
			ngctl connect ${ETHER}: ${BRIDGE_NAME}: \
			    lower link${LINKNUM} || exit 1
		fi
		LINKNUM=`expr ${LINKNUM} + 1`
	done

	# Hook up local interface, if any.
	for LOCAL_IFACE in ${LOCAL_IFACES}; do
		ngctl connect ${LOCAL_IFACE}: ${BRIDGE_NAME}: \
		    upper link${LINKNUM} || exit 1
		LINKNUM=`expr ${LINKNUM} + 1`
	done

	# Set all interfaces in promiscuous mode and don't overwrite src addr.
	for ETHER in ${BRIDGE_IFACES}; do
		ngctl msg ${ETHER}: setpromisc 1 || exit 1
		ngctl msg ${ETHER}: setautosrc 0 || exit 1
	done
}

# Stop routine.
bridge_stop() {
	ngctl kill ${BRIDGE_NAME}: >/dev/null 2>&1
	for ETHER in ${BRIDGE_IFACES} ${LOCAL_IFACES}; do
		ngctl kill ${ETHER}: >/dev/null 2>&1
	done
}

# Stats routine.
bridge_stats() {

	# Make sure node exists.
	bridge_verify

	echo ""
	echo "Statistics for bridging network ${BRIDGE_NAME}:"
	echo ""
	LINKNUM=0
	for ETHER in ${BRIDGE_IFACES}; do
		echo "Network interface ${ETHER}:"
		bridge_linkstats ${LINKNUM}
		LINKNUM=`expr ${LINKNUM} + 1`
	done
	for LOCAL_IFACE in ${LOCAL_IFACES}; do
		echo "Local host interface ${LOCAL_IFACE}:"
		bridge_linkstats ${LINKNUM}
		LINKNUM=`expr ${LINKNUM} + 1`
	done
}

# Main entry point.
case $1 in
	start)
		bridge_start
		;;
	stats)
		bridge_verify
		bridge_stats
		;;
	stop)
		bridge_verify
		bridge_stop
		;;
	*)
		echo "usage: $0 [ start | stop | stats ]"
		exit 1
esac