2410开发板上实现DHCP自动获取IP地址

1．在内核中添加以下选项：
Networking--->

• Networking support
  Networking options--->
  Packet socket //添加.配置CONFIG_PACKET
  [ * ] IP: DHCP support //添加
  [ * ] Network packet filtering (replaces ipchains)---> //添加，后面子选项可不选，配置CONFIG_NETFILTER
  说明：若没选 Packet socket, [ * ] Network packet filtering (replaces ipchains)--->选项，在执行udhcpc命令时出现如下错误：
  ~ # 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中添加以下选项：
  Networking Utilities--->
  udhcp Server/Client--->
  [] udhcp Server (udhcpd) //在此不作服务端，故不选。生成udhcpd命令
  
• udhcp Client (udhcpc) //生成udhcpc命令
  [ ] 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交叉编译得到udhcpd,udhcpc命令copy到usr/sbin下就可以了。
  我从 网上下的udhcp_0.9.8cvs20050303.orig.tar.gz文件
  解压后修改Makefile文件
  在19行添加CROSS_COMPILE=arm-linux-
  注释12行的COMBINED_BINARY=1，否则不生成udhcpc命令。
  3．建相关配置文件
  从busybox的examples/udhcp/下copysimple.script文件到开发板/usr/share/udhcpc/下，并重命名为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，执行udhcpc就可自动获取IP地址了，以下是执行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

===============================================

今天在我的2410上搞定摄像头。交叉编译gspca驱动，配置linux2.6.20.3使其支持V4L，不用选择linux2.6自带的ZC0301驱动。发现可以搞定，但是2410性能交叉，640＊480的VGA输出，摄像头分辨率大小不能设太大，否则很慢。我设定为176＊144.

今天顺便上busybox.net看了看，发现稳定版已经到1.5.1，于是重新把我现在用的1.4.2换成1.5.1。
发现原来ls -l /dev出现segment fault的BUG消除了！
顺便加上了dhcp client的支持。看了写资料，方法：

在KERNEL中需要将 Packet socket和IP: DHCP support编译进内核或编译成模块。在编译Busybox时把 Networking Utilities下udhcp Server/Client中的 udhcp Client (udhcpc)选上。
关键点要把examples/udhcp/simple.script 脚本文件做为default.script拷贝到/usr/share/udhcpc/default.script

运行udhcpc
~ # udhcpc
udhcpc (v1.5.1) started
Sending discover...
Sending select for 59.64.134.99...
Sending select for 59.64.134.99...
Sending select for 59.64.134.99...
Lease of 59.64.134.99 obtained, lease time 10800
deleting routers
route: SIOC[ADD|DEL]RT: No such process
adding dns 211.68.71.4
adding dns 211.68.71.5
adding dns 202.106.196.115
adding dns 202.106.0.20