udhcp는 dhcp client 겸, network setting tool이다.
아무튼 busybox에서 채택하고 있는 dhcp client 이며, 나름 쓸만한 녀석이다.

######################################################################
# /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)
#
# A "#" character in the very first column makes the rest of the line
# be ignored. Blank lines are ignored. Lines may be indented freely.
# A "\" character at the very end of the line indicates the next line
# should be treated as a continuation of the current one.
#
# The "pre-up", "up", "down" and "post-down" options are valid for all
# interfaces, and may be specified multiple times. All other options
# may only be specified once.
#
# See the interfaces(5) manpage for information on what options are
# available.
######################################################################

# We always want the loopback interface.
#
# auto lo
# iface lo inet loopback

# An example ethernet card setup: (broadcast and gateway are optional)
#
# auto eth0
# iface eth0 inet static
#     address 192.168.0.42
#     network 192.168.0.0
#     netmask 255.255.255.0
#     broadcast 192.168.0.255
#     gateway 192.168.0.1

# A more complicated ethernet setup, with a less common netmask, and a downright
# weird broadcast address: (the "up" lines are executed verbatim when the
# interface is brought up, the "down" lines when it's brought down)
#
# auto eth0
# iface eth0 inet static
#     address 192.168.1.42
#     network 192.168.1.0
#     netmask 255.255.255.128
#     broadcast 192.168.1.0
#     up route add -net 192.168.1.128 netmask 255.255.255.128 gw 192.168.1.2
#     up route add default gw 192.168.1.200
#     down route del default gw 192.168.1.200
#     down route del -net 192.168.1.128 netmask 255.255.255.128 gw 192.168.1.2

# A more complicated ethernet setup with a single ethernet card with
# two interfaces.
# Note: This happens to work since ifconfig handles it that way, not because
# ifup/down handles the ':' any differently.
# Warning: There is a known bug if you do this, since the state will not
# be properly defined if you try to 'ifdown eth0' when both interfaces
# are up. The ifconfig program will not remove eth0 but it will be
# removed from the interfaces state so you will see it up until you execute:
# 'ifdown eth0:1 ; ifup eth0; ifdown eth0'
# BTW, this is "bug" #193679 (it's not really a bug, it's more of a
# limitation)
#
# auto eth0 eth0:1
# iface eth0 inet static
#     address 192.168.0.100
#     network 192.168.0.0
#     netmask 255.255.255.0
#     broadcast 192.168.0.255
#     gateway 192.168.0.1
# iface eth0:1 inet static
#     address 192.168.0.200
#     network 192.168.0.0
#     netmask 255.255.255.0

# "pre-up" and "post-down" commands are also available. In addition, the
# exit status of these commands are checked, and if any fail, configuration
# (or deconfiguration) is aborted. So:
#
# auto eth0
# iface eth0 inet dhcp
#     pre-up [ -f /etc/network/local-network-ok ]
#
# will allow you to only have eth0 brought up when the file
# /etc/network/local-network-ok exists.

# Two ethernet interfaces, one connected to a trusted LAN, the other to
# the untrusted Internet. If their MAC addresses get swapped (because an
# updated kernel uses a different order when probing for network cards,
# say), then they don't get brought up at all.
#
# auto eth0 eth1
# iface eth0 inet static
#     address 192.168.42.1
#     netmask 255.255.255.0
#     pre-up /path/to/check-mac-address.sh eth0 11:22:33:44:55:66
#     pre-up /usr/local/sbin/enable-masq
# iface eth1 inet dhcp
#     pre-up /path/to/check-mac-address.sh eth1 AA:BB:CC:DD:EE:FF
#     pre-up /usr/local/sbin/firewall

# Two ethernet interfaces, one connected to a trusted LAN, the other to
# the untrusted Internet, identified by MAC address rather than interface
# name:
#
# auto eth0 eth1
# mapping eth0 eth1
#     script /path/to/get-mac-address.sh
#     map 11:22:33:44:55:66 lan
#     map AA:BB:CC:DD:EE:FF internet
# iface lan inet static
#     address 192.168.42.1
#     netmask 255.255.255.0
#     pre-up /usr/local/sbin/enable-masq $IFACE
# iface internet inet dhcp
#     pre-up /usr/local/sbin/firewall $IFACE

# A PCMCIA interface for a laptop that is used in different locations:
# (note the lack of an "auto" line for any of these)
#
# mapping eth0
#    script /path/to/pcmcia-compat.sh
#    map home,*,*,*                  home
#    map work,*,*,00:11:22:33:44:55  work-wireless
#    map work,*,*,01:12:23:34:45:50  work-static
#
# iface home inet dhcp
# iface work-wireless bootp
# iface work-static static
#     address 10.15.43.23
#     netmask 255.255.255.0
#     gateway 10.15.43.1
#
# Note, this won't work unless you specifically change the file
# /etc/pcmcia/network to look more like:
#
#     if [ -r ./shared ] ; then . ./shared ; else . /etc/pcmcia/shared ; fi
#     get_info $DEVICE
#     case "$ACTION" in
#         'start')
#             /sbin/ifup $DEVICE
#             ;;
#         'stop')
#             /sbin/ifdown $DEVICE
#             ;;
#     esac
#     exit 0

# An alternate way of doing the same thing: (in this case identifying
# where the laptop is is done by configuring the interface as various
# options, and seeing if a computer that is known to be on each particular
# network will respond to pings. The various numbers here need to be chosen
# with a great deal of care.)
#
# mapping eth0
#    script /path/to/ping-places.sh
#    map 192.168.42.254/24 192.168.42.1 home
#    map 10.15.43.254/24 10.15.43.1 work-wireless
#    map 10.15.43.23/24 10.15.43.1 work-static
#
# iface home inet dhcp
# iface work-wireless bootp
# iface work-static static
#     address 10.15.43.23
#     netmask 255.255.255.0
#     gateway 10.15.43.1
#
# Note that the ping-places script requires the iproute package installed,
# and the same changes to /etc/pcmcia/network are required for this as for
# the previous example.

# Set up an interface to read all the traffic on the network. This
# configuration can be useful to setup Network Intrusion Detection
# sensors in 'stealth'-type configuration. This prevents the NIDS
# system to be a direct target in a hostile network since they have
# no IP address on the network. Notice, however, that there have been
# known bugs over time in sensors part of NIDS (for example see
# DSA-297 related to Snort) and remote buffer overflows might even be
# triggered by network packet processing.
#
# auto eth0
# iface eth0 inet manual
#     up ifconfig $IFACE 0.0.0.0 up
#       up ip link set $IFACE promisc on
#       down ip link set $IFACE promisc off
#       down ifconfig $IFACE down

# Set up an interface which will not be allocated an IP address by
# ifupdown but will be configured through external programs. This
# can be useful to setup interfaces configured through other programs,
# like, for example, PPPOE scripts.
#
# auto eth0
# iface eth0 inet manual
#       up ifconfig $IFACE 0.0.0.0 up
#       up /usr/local/bin/myconfigscript
#       down ifconfig $IFACE down

[링크 : http://www.cyberciti.biz/faq/setting-up-an-network-interfaces-file/]

[링크 : http://www.cyberciti.biz/tips/howto-ubuntu-linux-convert-dhcp-network-configuration-to-static-ip-configuration.html]

[링크 : http://pig.cs.upt.ro/cgi-bin/man/man2html?interfaces+5]
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static / dhcp 로 변경하는 일련의 함수들을 만들었는데,

static -> interface 파일변경 -> ifdown -> ifup -> dhcp
dhcp -> interface 파일변경 -> ifdown -> ifup -> static

순서로 작동되도록 했는데,
static에서 dhcp로는 udhcp 프로세스가 이상없이 작동하는데
dhcp에서 static으로는 udhcp 프로세스가 죽지 않는다.

그래서 계속 순환하면 udhcp 프로세스가 쌓여간다(좀비는 아니고 Sleep 상태)


아무튼,

dhcp -> ifdown -> interface 파일변경 -> ifup -> static
으로 하니 제대로 작동한다.

아마 interface 파일 내용에
ifdown에 관련한 내용이 제대로 들어 있지않아 그랬던 것으로 보인다.


상관이 있을지 없을지 모르는 링크
[링크 : http://lists.busybox.net/pipermail/busybox/2007-July/062158.html]
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Linux2009.07.31 13:40
start-stop-daemon은 rc.d 에서 사용하는 녀석인데..
프로그램인지, 스크립트인지는 모르겠다.


간단하게 데몬 프로그램을 실행하고 자동으로 추적해서 죽이는 녀석이다.
service xinetd start / stop / restart
등의 녀석을 구현해주는 착한 녀석이다.

OPTIONS

-x|--exec executable
    Check for processes that are instances of this executable (according to /proc/pid/exe ).
-p|--pidfile pid-file
    Check whether a process has created the file pid-file.
-u|--user username|uid
    Check for processes owned by the user specified by username or uid.
-g|--group group|gid
    Change to group or gid when starting the process.
-n|--name process-name
    Check for processes with the name process-name (according to /proc/pid/stat).

아무튼, -x 로 되어서 제대로 찾지를 못해 죽이지 못하길래
-n 으로 해주었더니 인자에 문제가 있었는지 못죽였다.
아무튼 -n의 경우에는 경로가 아니라 실행파일의 이름만 넣어주면 된다.

예를 들어 /sbin/udhcpc의 경우에는
-name udhcpc 하면 종료해준다.





[링크 : http://olympus.het.brown.edu/cgi-bin/man/man2html?start-stop-daemon+8]
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#!/bin/sh

/bin/run-parts --arg=$1 /etc/udhcpc.d

[링크 : http://www.doit.org/udhcpc/udhcpc.script]

#!/bin/sh
# /etc/init.d/udhcpc: start or stop udhcpc client

set -e

PATH=/bin:/usr/bin:/sbin:/usr/sbin
DAEMON=/sbin/udhcpc

test -x $DAEMON || exit 0

case "$1" in
  start)
    echo -n "Starting DHCP client: udhcpc"
    start-stop-daemon --start --quiet --exec $DAEMON \
      -- --script=/etc/udhcpc.script || echo -n " already running"
    echo "."
  ;;

  restart)
    /etc/init.d/udhcpc stop
    /etc/init.d/udhcpc start
  ;;

  reload)
  ;;

  force-reload)
  ;;

  stop)
    echo -n "Stopping DHCP client: udhcpc"
    start-stop-daemon --stop --quiet --exec $DAEMON || echo -n " not running"
    echo "."
  ;;

  renew)
    start-stop-daemon --signal USR1 --stop --quiet --exec $DAEMON || echo -n " not running"
  ;;

  release)
    start-stop-daemon --signal USR2 --stop --quiet --exec $DAEMON || echo -n " not running"
  ;;

  *)
    echo "Usage: /etc/init.d/udhcpc {start|stop|restart|reload|force-reload}"
    exit 1
    ;;
esac

exit 0

[링크 : http://www.doit.org/udhcpc/udhcpc]

[링크 : http://www.doit.org/udhcpc/]
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  1. ㅇㅇ

    자세히좀 적어놔라

    2009.08.01 03:08 신고 [ ADDR : EDIT/ DEL : REPLY ]

$ ls /bin/udhcpc*
lrwxrwxrwx 1 root     root 7 Jul 29 14:49 udhcpc -> busybox
lrwxrwxrwx 1 root     root 7 Jul 29 14:49 udhcpd -> busybox

요즘 busybox는 udhcp 라는 dhcp 서버/클라이언트가 내장되어있다.
물론 기본값으로 busybox에 포함되긴 하지만, 확인 후 사용해야 한다.

아무튼, 옵션은 설정되어 있었음에도 불구하고
심볼릭 링크와, 스크립트가 생성되어 있지 않았다.

make menuconfig


/sbin/udhcpc - udhcp Client
/sbin/udhcpd - udhcp Daemon
/usr/share/udhcpc/default.script - 기본 dhcp 스크립트

default.script




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