#!/bin/sh

# You don't usually need to touch this file at all, the full configuration
# of the bridge can be done in a standard way on /etc/network/interfaces.

# Have a look at /usr/share/doc/bridge-utils/README.Debian if you want
# more info about the way on wich a bridge is set up on Debian.

if [ ! -x /usr/sbin/brctl ]
then
  exit 0
fi

case "$IF_BRIDGE_PORTS" in
    "")
	exit 0
	;;
    none)
	INTERFACES=""
	;;
    *)
	INTERFACES="$IF_BRIDGE_PORTS"
	;;
esac

# Previous work (create the interface)
if [ "$MODE" = "start" ] ; then
  brctl addbr $IFACE || exit 1
# Wait for the ports to become available
  if [ "$IF_BRIDGE_WAITPORT" ]
  then
    set x $IF_BRIDGE_WAITPORT &&   
    shift &&
    WAIT="$1" &&
    shift &&
    WAITPORT="$@" &&
    if [ -z "$WAITPORT" ];then WAITPORT="$IF_BRIDGE_PORTS";fi &&
    STARTTIME=$(date +%s) &&
    NOTFOUND="true" &&
    /bin/echo -e "\nWaiting for a max of $WAIT seconds for $WAITPORT to become available." &&
    while [ "$(($(date +%s)-$STARTTIME))" -le "$WAIT" ] && [ -n "$NOTFOUND" ]
    do
      NOTFOUND=""
      for i in $WAITPORT
      do
        if ! grep -q "^[\ ]*$i:.*$" /proc/net/dev;then NOTFOUND="true";fi
      done
      if [ -n "$NOTFOUND" ];then sleep 1;fi
    done
  fi
# Previous work (stop the interface)
elif [ "$MODE" = "stop" ];  then
  ifconfig $IFACE down || exit 1
fi

all_interfaces= &&
unset all_interfaces &&
set x $INTERFACES &&
shift &&
while [ x"${1+set}" = xset ]
do
  # For compatibility: the `all' option.
  case $1 in
      all)
	shift &&
	set regex eth.\* noregex "$@"
	;;
  esac

  # Primitive state machine...
  case $1-`uname -s` in
      regex-Linux)
	all_interfaces=`sed -n 's%^[\ ]*\([^:]*\):.*$%\1%p' < /proc/net/dev`
	shift
	;;
      regex-*)
	echo -n "$0 needs to be ported for your `uname -s` system.  " >&2
	echo "Trying to continue nevertheless." >&2
	shift
	;;
      noregex-*)
	all_interfaces=
	unset all_interfaces
	shift
	;;
  esac

  case ${all_interfaces+regex}-${1+set} in
      regex-set)
	# The following interface specification are to be parsed as regular
	# expressions against all interfaces the system provides.
	i=`egrep "^$1$" << EOAI
$all_interfaces
EOAI
`
	shift
	;;
      *-set)
	# Literal interfaces.
	i=$1
	shift
	;;
      *)
	# No interface specification is following.
	i=
	;;
  esac

  for port in $i
  do
    # We attach and configure each port of the bridge
    if [ "$MODE" = "start" ] ; then
      if [ -x /etc/network/if-pre-up.d/vlan ]; then
        env IFACE=$port /etc/network/if-pre-up.d/vlan
      fi
      if [ "$IF_BRIDGE_HW" ]
      then
         ifconfig $port down; ifconfig $port hw ether $IF_BRIDGE_HW
      fi
      brctl addif $IFACE $port && ifconfig $port 0.0.0.0 up
    # We detach each port of the bridge
    elif [ "$MODE" = "stop" ];  then
      ifconfig $port down && brctl delif $IFACE $port && \
        if [ -x /etc/network/if-post-down.d/vlan ]; then
          env IFACE=$port /etc/network/if-post-down.d/vlan
        fi
    fi
  done
done

# We finish setting up the bridge
if [ "$MODE" = "start" ] ; then

  if [ "$IF_BRIDGE_AGEING" ]
  then
    brctl setageing $IFACE $IF_BRIDGE_AGEING
  fi

  if [ "$IF_BRIDGE_BRIDGEPRIO" ]
  then
    brctl setbridgeprio $IFACE $IF_BRIDGE_BRIDGEPRIO
  fi

  if [ "$IF_BRIDGE_FD" ]
  then
    brctl setfd $IFACE $IF_BRIDGE_FD
  fi

  if [ "$IF_BRIDGE_GCINT" ]
  then
    brctl setgcint $IFACE $IF_BRIDGE_GCINT
  fi

  if [ "$IF_BRIDGE_HELLO" ]
  then
    brctl sethello $IFACE $IF_BRIDGE_HELLO
  fi

  if [ "$IF_BRIDGE_MAXAGE" ]
  then
    brctl setmaxage $IFACE $IF_BRIDGE_MAXAGE
  fi

  if [ "$IF_BRIDGE_PATHCOST" ]
  then
    brctl setpathcost $IFACE $IF_BRIDGE_PATHCOST
  fi

  if [ "$IF_BRIDGE_PORTPRIO" ]
  then
    brctl setportprio $IFACE $IF_BRIDGE_PORTPRIO
  fi

  if [ "$IF_BRIDGE_STP" ]
  then
    brctl stp $IFACE $IF_BRIDGE_STP
  fi


  # We activate the bridge
  ifconfig $IFACE 0.0.0.0 up


  # Calculate the maximum time to wait for the bridge to be ready
  if [ "$IF_BRIDGE_MAXWAIT" ]
  then
    MAXWAIT=$IF_BRIDGE_MAXWAIT
  else
    MAXWAIT=$(brctl showstp $IFACE|sed -n 's/^.*forward delay[ \t]*\(.*\)\..*bridge forward delay[ \t]*\(.*\)\..*$/\1 \2/p')
    if [ "$MAXWAIT" ]
    then
      if [ ${MAXWAIT% *} -gt ${MAXWAIT#* } ]
      then
        MAXWAIT=$((2*(${MAXWAIT% *}+1)))
      else
        MAXWAIT=$((2*(${MAXWAIT#* }+1)))
      fi
    else
      if [ "$IF_BRIDGE_FD" ]
      then
        MAXWAIT=$((2*(${IF_BRIDGE_FD%.*}+1)))
      else
        MAXWAIT=32
      fi
      /bin/echo -e "\nWaiting $MAXWAIT seconds for $IFACE to get ready."
      sleep $MAXWAIT
      MAXWAIT=0
    fi
  fi

  # Wait for the bridge to be ready
  if [ "$MAXWAIT" != 0 ]
  then
    /bin/echo -e "\nWaiting for $IFACE to get ready (MAXWAIT is $MAXWAIT seconds)."

    unset BREADY
    unset TRANSITIONED
    COUNT=0

    while [ ! "$BREADY" -a $COUNT -lt $MAXWAIT ]
    do
      sleep 1
      COUNT=$(($COUNT+1))
      BREADY=true
      for i in $(brctl showstp $IFACE|sed -n 's/^.*port id.*state[ \t]*\(.*\)$/\1/p')
      do
        if [ "$i" = "listening" -o "$i" = "learning" -o "$i" = "forwarding" -o "$i" = "blocking" ]
        then
          TRANSITIONED=true
        fi
        if [ "$i" != "forwarding" -a "$i" != "blocking" ] && [ ! "$TRANSITIONED" -o "$i" != "disabled" ]
        then
          unset BREADY
        fi
      done
    done

  fi

# Finally we destroy the interface
elif [ "$MODE" = "stop" ];  then

  brctl delbr $IFACE

fi