#!/bin/sh
#
# $Id: macos,v 1.4 2011/09/20 16:59:54 sar Exp $
#
# automous run of this script will commit the DNS setting
#

if [ -x /usr/bin/logger ]; then
	LOGGER="/usr/bin/logger -s -p user.notice -t dhclient"
else
	LOGGER=echo
fi

to_commit="yes"

make_resolv_conf() {
  to_commit="no"
  if [ "x${new_dhcp6_name_servers}" != x ]; then
    ( cat /dev/null > /var/run/resolv.conf.dhclient6 )
    exit_status=$?
    if [ $exit_status -ne 0 ]; then
      $LOGGER "Unable to create /var/run/resolv.conf.dhclient6: Error $exit_status"
    else
      if [ "x${new_dhcp6_domain_search}" != x ]; then
	( echo search ${new_dhcp6_domain_search} >> /var/run/resolv.conf.dhclient6 )
	exit_status=$?
      fi
      for nameserver in ${new_dhcp6_name_servers} ; do
	if [ $exit_status -ne 0 ]; then
	  break
	fi
	# If the nameserver has a link-local address
	# add a <zone_id> (interface name) to it.
	case $nameserver in
	    fe80:*) zone_id="%$interface";;
	    FE80:*) zone_id="%$interface";;
	   *)      zone_id="";;
	esac
        ( echo nameserver ${nameserver}$zone_id >> /etc/resolv.conf.dhclient6 )
	exit_status=$?
      done

      if [ $exit_status -eq 0 ]; then
	to_commit="force"
	commit_resolv_conf
      fi
    fi
  fi
}

# Try to commit /var/run/resolv.conf.dhclient6 contents to
# System Configuration framework's Dynamic Store.
# Note this will be cleared by the next location change
# or preempted by IPv4.
#
# The System Configuration agent "IPMonitor" gets the DNS configuration
# from the IPv4 or IPv6 primary service in the Dynamic Store
# (managed by configd).
commit_resolv_conf() {
  if [ -f /var/run/resolv.conf.dhclient6 ]; then
    if [ -x /usr/sbin/scutil ]; then
      serviceID=`echo show State:/Network/Global/IPv6 | \
          /usr/sbin/scutil | \
          awk '/PrimaryService/ { print $3 }'`
      echo $serviceID
      if [ x$serviceID = x ]; then
        $LOGGER "Can't find the primary IPv6 service"
      else
        tmp=`mktemp SC_dhclient6.XXXXXXXXXX`
        echo list | /usr/sbin/scutil > /tmp/$tmp
        grep -q State:/Network/Service/$serviceID/DNS /tmp/$tmp
        grep_status=$?
        if [ $grep_status -eq 0 ]; then
          $LOGGER "DNS service already set in primary IPv6 service"
          rm /tmp/$tmp
        else
          res=/var/run/resolv.conf.dhclient6
          cp /dev/null /tmp/$tmp
          grep -q '^nameserver' $res
          grep_status=$?
          if [ $grep_status -eq 0 ]; then
            echo d.add ServerAddresses '*' \
                 `awk 'BEGIN { n="" } \
                       /^nameserver/ { n=n " " $2 } \
                       END { print n}' < $res` >> /tmp/$tmp
          fi
          grep -q '^search' $res
          grep_status=$?
          if [ $grep_status -eq 0 ]; then
            echo d.add SearchDomains '*' \
                 `sed 's/^search//' < $res` >> /tmp/$tmp
          fi
          echo set State:/Network/Service/$serviceID/DNS >> /tmp/$tmp
          echo quit >> /tmp/$tmp
          cat /tmp/$tmp
          /usr/sbin/scutil < /tmp/$tmp
          rm /tmp/$tmp
        fi
      fi
    else
      $LOGGER "Can't find SystemConfiguration tools."
    fi
  else
    if [ $to_commit = force ]; then
      $LOGGER "Can't find /var/run/resolv.conf.dhclient6"
    fi
  fi
  to_commit="done"
}

# This function was largely borrowed from dhclient-script that
# ships with Centos, authored by Jiri Popelka and David Cantrell
# of Redhat. Thanks guys.
add_ipv6_addr_with_DAD() {
    ifconfig ${interface} inet6 ${new_ip6_address}/${new_ip6_prefixlen} alias

    if [ ${dad_wait_time} -le 0 ]
    then
        # if we're not waiting for DAD, assume we're good
        return 0
    fi

    # Repeatedly test whether newly added address passed
    # duplicate address detection (DAD)
    for i in $(seq 1 ${dad_wait_time}); do
        sleep 1 # give the DAD some time

        addr=$(ifconfig ${interface} \
            | grep "${new_ip6_address} prefixlen ${new_ip6_prefixlen}")

        # tentative flag == DAD is still not complete
        tentative=$(echo "${addr}" | grep tentative)
        # dadfailed flag == address is already in use somewhere else
        dadfailed=$(echo "${addr}" | grep duplicated)

        if [ -n "${dadfailed}" ] ; then
            # dad failed, remove the address
            ifconfig ${interface} inet6 ${new_ip6_address}/${new_ip6_prefixlen} -alias
            exit_with_hooks 3
        fi

        if [ -z "${tentative}" ] ; then
            if [ -n "${addr}" ]; then
                # DAD is over
                return 0
            else
                # address was auto-removed (or not added at all)
                exit_with_hooks 3
            fi
        fi
    done

    return 0
}

# Must be used on exit.   Invokes the local dhcp client exit hooks, if any.
exit_with_hooks() {
  exit_status=$1
  if [ -f /etc/dhclient-exit-hooks ]; then
    . /etc/dhclient-exit-hooks
  fi
# probably should do something with exit status of the local script
  exit $exit_status
}

# Invoke the local dhcp client enter hooks, if they exist.
if [ -f /etc/dhclient-enter-hooks ]; then
  exit_status=0
  . /etc/dhclient-enter-hooks
  # allow the local script to abort processing of this state
  # local script must set exit_status variable to nonzero.
  if [ $exit_status -ne 0 ]; then
    exit $exit_status
  fi
fi

if [ x$reason = xMEDIUM ]; then
  eval "ifconfig $interface $medium"
  eval "ifconfig $interface inet -alias 0.0.0.0 $medium" >/dev/null 2>&1
  sleep 1
  exit_with_hooks 0
fi

###
### DHCPv6 Handlers
###

if [ x$reason = xPREINIT6 ]; then
  # Ensure interface is up.
  ifconfig ${interface} up

  # We need to give the kernel some time to active interface
  interface_up_wait_time=5
  for i in $(seq 0 ${interface_up_wait_time})
  do
      ifconfig ${interface} | grep inactive &> /dev/null
      if [ $? -ne 0 ]; then
          break;
      fi
      sleep 1
  done

  # XXX: Remove any stale addresses from aborted clients.

  # Wait for duplicate address detection for this interface if the
  # --dad-wait-time parameter has been specified and is greater than
  # zero.
  if [ ${dad_wait_time} -gt 0 ]; then
      # Check if any IPv6 address on this interface is marked as
      # tentative.
      ifconfig ${interface} | grep inet6 | grep tentative \
          &> /dev/null
      if [ $? -eq 0 ]; then
          # Wait for duplicate address detection to complete or for
          # the timeout specified as --dad-wait-time.
          for i in $(seq 0 $dad_wait_time)
          do
              # We're going to poll for the tentative flag every second.
              sleep 1
              ifconfig ${interface} | grep inet6 | grep tentative \
                  &> /dev/null
              if [ $? -ne 0 ]; then
                  break;
              fi
          done
      fi
  fi

  exit_with_hooks 0
fi

if [ x${old_ip6_prefix} != x ] || [ x${new_ip6_prefix} != x ]; then
    echo Prefix $reason old=${old_ip6_prefix} new=${new_ip6_prefix}

    exit_with_hooks 0
fi

if [ x$reason = xBOUND6 ]; then
  if [ x${new_ip6_address} = x ] || [ x${new_ip6_prefixlen} = x ]; then
    exit_with_hooks 2;
  fi

  # Add address to interface, check for DAD if dad_wait_time > 0
  add_ipv6_addr_with_DAD

  # Check for nameserver options.
  make_resolv_conf

  exit_with_hooks 0
fi

if [ x$reason = xRENEW6 ] || [ x$reason = xREBIND6 ]; then
  # Make sure nothing has moved around on us.

  # Nameservers/domains/etc.
  if [ "x${new_dhcp6_name_servers}" != "x${old_dhcp6_name_servers}" ] ||
     [ "x${new_dhcp6_domain_search}" != "x${old_dhcp6_domain_search}" ]; then
    make_resolv_conf
  fi

  exit_with_hooks 0
fi

if [ x$reason = xDEPREF6 ]; then
  if [ x${new_ip6_address} = x ]; then
    exit_with_hooks 2;
  fi

  ifconfig ${interface} inet6 ${new_ip6_address} deprecated

  exit_with_hooks 0
fi

if [ x$reason = xEXPIRE6 -o x$reason = xRELEASE6 -o x$reason = xSTOP6 ]; then
  if [ x${old_ip6_address} = x ] || [ x${old_ip6_prefixlen} = x ]; then
    exit_with_hooks 2;
  fi

  ifconfig ${interface} inet6 ${old_ip6_address}/${old_ip6_prefixlen} -alias

  exit_with_hooks 0
fi

if [ $to_commit = yes ]; then
  commit_resolv_conf
fi

exit_with_hooks 0