#!/bin/sh

if [ -z "$1" ]; then
  echo "Usage: ping_discovery <interface> <ip-map>"
  exit 1
fi  

INTERFACE="$1"
IPMAPFILE="$2"
SCHEME_DIR=/var/lib/laptop-net/schemes

export PATH=/bin:/usr/bin:/sbin:/usr/sbin

#-----------------------------------------------------------------------------
# Allow for extremely long negotiation times with stoopid switches

sleep 30

#------------------------------------------------------------------------------
# Load LAPTOP-NET definitions and routines

# . /usr/share/laptop-net/shared.sh

#------------------------------------------------------------------------------
# Load available schemes from /etc/laptop-net/ip-map.

SCHEME=`grep -v -E "(^$|#)" ${IPMAPFILE} | awk '{print $1}'`

if [ -z "$SCHEME" ]; then
    echo "@NO-CHOICES@"
    exit 1
fi    

#------------------------------------------------------------------------------
# Test interface configuration: if already configured, return scheme; if
# unknown configuration, bring the interface down; if not configured, continue

IFTEST=`ifconfig | grep -A 1 "${INTERFACE}" | tail -1 | sed -e "s/:/ /" | awk '{print $3}'`

if [ -n "${IFTEST}" ]; then
  for s in ${SCHEME}; do
    IFACE=${SCHEME_DIR}/$s
    ADDRESS=`grep "address" ${IFACE} | awk '{print $2}'`
    if [ "${IFTEST}" = "${ADDRESS}" ]; then
      echo $s
      exit 0
    fi
  done
  ifconfig ${INTERFACE} down
fi  

#------------------------------------------------------------------------------
# Loop over all non-DHCP schemes, try to bring up the interface and ping the 
# gateway

for s in ${SCHEME}; do
    IFACE=${SCHEME_DIR}/$s
    DHCP=`grep "dhcp" $IFACE`
    if [ -z "$DHCP" ]; then
      ADDRESS=`grep "address" ${IFACE} | awk '{print $2}'`
      NETMASK=`grep "netmask" ${IFACE} | awk '{print $2}'`
      BROADCAST=`grep "broadcast" ${IFACE} | awk '{print $2}'`
      GATEWAY=`grep "gateway" ${IFACE} | awk '{print $2}'`
      ifconfig ${INTERFACE} ${ADDRESS} netmask ${NETMASK} broadcast ${BROADCAST} up
      ping -r -c 1 ${GATEWAY} &> /dev/null
      SUCCESS=$?
      ifconfig ${INTERFACE} down
      if [ "${SUCCESS}" = 0 ]; then
        echo $s
        exit
      fi
    fi
done

#------------------------------------------------------------------------------
# Try to bring up the interface using DHCP (somewhat ugly since the DHCLIENT
# does not exit on failures but brings up the interface anyway)

for s in ${SCHEME}; do
    IFACE=${SCHEME_DIR}/$s
    DHCP=`grep "dhcp" $IFACE`
    if [ -n "$DHCP" ]; then
      /sbin/dhclient-2.2.x -e ${INTERFACE} &> /tmp/DHCLIENT.log
      SUCCESS=`grep "DHCPACK" /tmp/DHCLIENT.log`
      kill `pidof dhclient-2.2.x`
      ifconfig "${INTERFACE}" down
      rm -f /tmp/DHCLIENT.log
      if [ -n "${SUCCESS}" ]; then
        echo $s
	exit
      fi
    fi
done    

#------------------------------------------------------------------------------
# No Network

echo "@NO-RESPONSES@"
exit 0