Commit 1cd15cb1 authored by Gustavo Zacarias's avatar Gustavo Zacarias Committed by Peter Korsgaard
Browse files

dhcp: update dhclient-script 

The previous no-op dhclient-script is useless and in fact can lead
users to believe things will work.
dhclient-script is supposed to, among many other things, bring the
interface up for dhclient to pump an address, set the interface
address, set resolv.conf appropiately and set the default gateway.
It's a complex script since it has to deal with a lot of details so
let's just use the best fit which is the OpenWRT one since it uses the
"legacy" tools (ifconfig, route, ...) which can be easily provided by
busybox and/or net-tools.
There are newer and more feature-complete versions around but they
require full iproute2 ip and wouldn't fit as well with the busybox-only
approach.

License: likely GPLv2+
Source:
http://git.openwrt.org/?p=packages.git;a=blob;f=net/isc-dhcp/files/dhclient-script;h=4afebc0ad20ebac51c5baae5ed01c6713e3a0fd0;hb=HEAD



Signed-off-by: default avatarGustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: default avatarPeter Korsgaard <peter@korsgaard.com>
parent 489848b1

package/dhcp/dhclient-script

+283 −1
Original line number Diff line number Diff line 
#!/bin/sh

# empty dhclient-script to keep dhclient from complaining
 


# dhclient-script from OpenWRT project

# http://git.openwrt.org/?p=packages.git;a=blob;f=net/isc-dhcp/files/dhclient-script;h=4afebc0ad20ebac51c5baae5ed01c6713e3a0fd0;hb=HEAD



make_resolv_conf() {

  if [ x"$new_domain_name_servers" != x ]; then

    cat /dev/null > /etc/resolv.conf.dhclient

    chmod 644 /etc/resolv.conf.dhclient

    if [ x"$new_domain_search" != x ]; then

      echo search $new_domain_search >> /etc/resolv.conf.dhclient

    elif [ x"$new_domain_name" != x ]; then

      # Note that the DHCP 'Domain Name Option' is really just a domain

      # name, and that this practice of using the domain name option as

      # a search path is both nonstandard and deprecated.

      echo search $new_domain_name >> /etc/resolv.conf.dhclient

    fi

    for nameserver in $new_domain_name_servers; do

      echo nameserver $nameserver >>/etc/resolv.conf.dhclient

    done



  elif [ "x${new_dhcp6_name_servers}" != x ] ; then

    cat /dev/null > /etc/resolv.conf.dhclient6

    chmod 644 /etc/resolv.conf.dhclient6



    if [ "x${new_dhcp6_domain_search}" != x ] ; then

      echo search ${new_dhcp6_domain_search} >> /etc/resolv.conf.dhclient6

    fi

    for nameserver in ${new_dhcp6_name_servers} ; do

      echo nameserver ${nameserver} >> /etc/resolv.conf.dhclient6

    done

  fi



  # if both v4 and v6 clients are running, concatenate results

  cat /etc/resolv.conf.* > /etc/resolv.conf

}



# 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



###

### DHCPv4 Handlers

###



if [ x$new_broadcast_address != x ]; then

  new_broadcast_arg="broadcast $new_broadcast_address"

fi

if [ x$new_subnet_mask != x ]; then

  new_subnet_arg="netmask $new_subnet_mask"

fi

if [ x$alias_subnet_mask != x ]; then

  alias_subnet_arg="netmask $alias_subnet_mask"

fi



if [ x$reason = xMEDIUM ]; then

  # Linux doesn't do mediums (ok, ok, media).

  exit_with_hooks 0

fi



if [ x$reason = xPREINIT ]; then

  if [ x$alias_ip_address != x ]; then

    # Bring down alias interface. Its routes will disappear too.

    ifconfig $interface:0- 0.0.0.0

  fi

  ifconfig $interface 0.0.0.0 up



  # We need to give the kernel some time to get the interface up.

  sleep 1



  exit_with_hooks 0

fi



if [ x$reason = xARPCHECK ] || [ x$reason = xARPSEND ]; then

  exit_with_hooks 0

fi

  

if [ x$reason = xBOUND ] || [ x$reason = xRENEW ] || \

   [ x$reason = xREBIND ] || [ x$reason = xREBOOT ]; then

  current_hostname=`hostname`

  if [ x$current_hostname = x ] || \

     [ x$current_hostname = x$old_host_name ]; then

    if [ x$current_hostname = x ] || \

       [ x$new_host_name != x$old_host_name ]; then

      hostname $new_host_name

    fi

  fi

    

  if [ x$old_ip_address != x ] && [ x$alias_ip_address != x ] && \

		[ x$alias_ip_address != x$old_ip_address ]; then

    # Possible new alias. Remove old alias.

    ifconfig $interface:0- 0.0.0.0

  fi

  if [ x$old_ip_address != x ] && [ x$old_ip_address != x$new_ip_address ]; then

    # IP address changed. Bringing down the interface will delete all routes,

    # and clear the ARP cache.

    ifconfig $interface 0.0.0.0 down



  fi

  if [ x$old_ip_address = x ] || [ x$old_ip_address != x$new_ip_address ] || \

     [ x$reason = xBOUND ] || [ x$reason = xREBOOT ]; then



    ifconfig $interface $new_ip_address $new_subnet_arg \

							$new_broadcast_arg

    for router in $new_routers; do

      if [ "x$new_subnet_mask" = "x255.255.255.255" ] ; then

	route add -host $router dev $interface

      fi

      route add default gw $router

    done

  fi

  if [ x$new_ip_address != x$alias_ip_address ] && [ x$alias_ip_address != x ];

   then

    ifconfig $interface:0- 0.0.0.0

    ifconfig $interface:0 $alias_ip_address $alias_subnet_arg

    route add -host $alias_ip_address $interface:0

  fi

  make_resolv_conf

  exit_with_hooks 0

fi



if [ x$reason = xEXPIRE ] || [ x$reason = xFAIL ] || [ x$reason = xRELEASE ] \

   || [ x$reason = xSTOP ]; then

  if [ x$alias_ip_address != x ]; then

    # Turn off alias interface.

    ifconfig $interface:0- 0.0.0.0

  fi

  if [ x$old_ip_address != x ]; then

    # Shut down interface, which will delete routes and clear arp cache.

    ifconfig $interface 0.0.0.0 down

  fi

  if [ x$alias_ip_address != x ]; then

    ifconfig $interface:0 $alias_ip_address $alias_subnet_arg

    route add -host $alias_ip_address $interface:0

  fi



  # remove v4 dns configuration for this interface

  rm /etc/resolv.conf.dhclient

  cat /etc/resolv.conf.* > /etc/resolv.conf



  exit_with_hooks 0

fi



if [ x$reason = xTIMEOUT ]; then

  if [ x$alias_ip_address != x ]; then

    ifconfig $interface:0- 0.0.0.0

  fi

  ifconfig $interface $new_ip_address $new_subnet_arg \

					$new_broadcast_arg

  set $new_routers

  if ping -q -c 1 $1; then

    if [ x$new_ip_address != x$alias_ip_address ] && \

			[ x$alias_ip_address != x ]; then

      ifconfig $interface:0 $alias_ip_address $alias_subnet_arg

      route add -host $alias_ip_address dev $interface:0

    fi

    for router in $new_routers; do

      if [ "x$new_subnet_mask" = "x255.255.255.255" ] ; then

	route add -host $router dev $interface

      fi

      route add default gw $router

    done

    make_resolv_conf

    exit_with_hooks 0

  fi

  ifconfig $interface 0.0.0.0 down

  exit_with_hooks 1

fi



###

### DHCPv6 Handlers

###



if [ x$reason = xPREINIT6 ]; then

  # Ensure interface is up.

  ifconfig ${interface} up



  # Remove any stale addresses from aborted clients.

  ip -f inet6 addr flush dev ${interface} scope global



  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



  ifconfig ${interface} add ${new_ip6_address}/${new_ip6_prefixlen}



  # Check for nameserver options.

  make_resolv_conf



### <<

  # Set up softwire tunnel

  if [ x${new_dhcp6_softwire} != x ] ; then

    /etc/init.d/dhclient stop

    ifconfig ${interface} 0.0.0.0

    ip -6 tunnel add tun0 mode ipip6 \

	remote ${new_dhcp6_softwire} \

	local ${new_ip6_address} \

	dev ${interface} encaplimit none

    ip link set tun0 up

    ip route add default dev tun0

  fi

### >>



  exit_with_hooks 0

fi



if [ x$reason = xRENEW6 ] || [ x$reason = xREBIND6 ]; then

  if [ x${new_ip6_address} = x ] || [ x${new_ip6_prefixlen} = x ] ; then

    exit_with_hooks 2;

  fi



  ifconfig ${interface} add ${new_ip6_address}/${new_ip6_prefixlen}



  # 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



  # Busybox ifconfig has no way to communicate this to the kernel, so ignore it



  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} del ${old_ip6_address}/${old_ip6_prefixlen}



  # remove v6 dns configuration for this interface

  rm /etc/resolv.conf.dhclient6

  cat /etc/resolv.conf.* > /etc/resolv.conf



### <<

  # Tear down softwire tunnel

  if [ x${old_dhcp6_softwire} != x ] ; then

    ip link set tun0 down

    ip tunnel del tun0

  fi

### >>



  exit_with_hooks 0

fi



exit_with_hooks 0