2410开发板上完成DHCP主动获取IP地址

条件：体系现已完成DNS（即运用ping 通）。

1．在内核中增加以下选项：
Networking—>

• Networking support
  Networking options—>
  Packet socket //增加.装备CONFIG_PACKET
  [ * ] IP: DHCP support //增加
  [ * ] Network packet filtering (replaces ipchains)—> //增加，后体面选项可不选，装备CONFIG_NETFILTER
  阐明：若没选 Packet socket, [ * ] Network packet filtering (replaces ipchains)—>选项，在履行udhcpc指令时呈现如下过错：
  ~ # udhcpc
  udhcpc (v0.9.9-pre) started
  udhcpc[208]: udhcpc (v0.9.9-pre) started

  FATAL: couldnt listen on socket, Address family not supported by protocol
  udhcpc[208]: FATAL: couldnt listen on socket, Address family not supported by protocol
  2．Busybox中增加以下选项：
  Networking Utilities—>
  udhcp Server/Client—>
  [] udhcp Server (udhcpd) //在此不作服务端，故不选。生成udhcpd指令

• udhcp Client (udhcpc) //生成udhcpc指令
  [ ] Lease display utility (dumpleases)
  [ ] Log udhcp messages to syslog (instead of stdout)
  [ ] Compile udhcp with noisy debugging messages
  若busybox没编译相应选项，也可从网上下载相应文件，用arm-linux穿插编译得到udhcpd,udhcpc指令copy到usr/sbin下就能够了。
  我从 网上下的udhcp_0.9.8cvs20050303.orig.tar.gz文件
  解压后修正Makefile文件
  在19行增加CROSS_COMPILE=arm-linux-
  注释12行的COMBINED_BINARY=1，不然不生成udhcpc指令。
  3．建相关装备文件
  从busybox的examples/udhcp/下copysimple.script文件到开发板/usr/share/udhcpc/下，偏重命名为default.script，udhcp_0.9.8cvs20050303.orig.tar.gz中也有这样的文件。
  [root@localhost root]# vi usr/share/udhcpc/default.script
  #!/bin/sh

  # udhcpc script edited by Tim Riker

  [ -z “$1” ] && echo “Error: should be called from udhcpc” && exit 1

  RESOLV_CONF=”/etc/resolv.conf”
  [ -n “$broadcast” ] && BROADCAST=”broadcast $broadcast”
  [ -n “$subnet” ] && NETMASK=”netmask $subnet”

  case “$1” in
  deconfig)
  /sbin/ifconfig $interface 0.0.0.0
  ;;

  renew|bound)
  /sbin/ifconfig $interface $ip $BROADCAST $NETMASK

  if [ -n “$router” ] ; then
  echo “deleting routers”
  while route del default gw 0.0.0.0 dev $interface ; do
  :
  done
  for i in $router ; do
  route add default gw $i dev $interface
  done
  fi

  echo -n > $RESOLV_CONF
  [ -n “$domain” ] && echo search $domain >> $RESOLV_CONF
  for i in $dns ; do
  echo adding dns $i
  echo nameserver $i >> $RESOLV_CONF
  done
  ;;
  esac

  exit 0

  4．重启开发板，履行udhcpc就可主动获取IP地址了，以下是履行udhcpc的输出信息：

  ~ # udhcpc
  udhcpc (v0.9.9-pre) started
  udhcpc[228]: udhcpc (v0.9.9-pre) started

  Sending discover…
  udhcpc[228]: Sending discover…

  Sending select for 192.168.1.109…
  udhcpc[228]: Sending select for 192.168.1.109…

  Lease of 192.168.1.109 obtained, lease time 86400
  udhcpc[228]: Lease of 192.168.1.109 obtained, lease time 86400

  deleting routers
  route: SIOC[ADD|DEL]RT: No such process
  adding dns 192.168.0.1
  ~ # ping www.baidu.com
  PING www.a.shifen.com (220.181.38.4): 56 data bytes
  64 bytes from 220.181.38.4: icmp_seq=0 ttl=52 time=1219.0 ms
  [1] + Stopped ping www.baidu.com

  5．如果是双网卡必须用参数指明
  例：udhcpc-ieth1