http://blog.chinaunix.net/uid-17188120-id-2820863.html

前提：系統已經實現DNS（即使用ping?www.baidu.com測試時能ping通）。

1．??在內核中添加以下選項：

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，后面子選項可不選，配置CONFIG_NETFILTER

說明：若沒選<* > Packet socket, [ * ] Network packet filtering (replaces ipchains)??--->選項，在執行udhcpc命令時出現如下錯誤：

~ # udhcpc

udhcpc (v0.9.9-pre) started

udhcpc[208]: udhcpc (v0.9.9-pre) started

?

FATAL: couldn't listen on socket, Address family not supported by protocol

udhcpc[208]: FATAL: couldn't listen on socket, Address family not supported by protocol

2．??Busybox中添加以下選項：

Networking Utilities??--->

???udhcp Server/Client??--->

????????[] udhcp Server (udhcpd)???????//在此不作服務端，故不選。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沒編譯相應選項，也可從網上下載相應文件，用arm-linux交叉編譯得到udhcpd,udhcpc命令copy到usr/sbin下就可以了。

我從?網上??下的udhcp_0.9.8cvs20050303.orig.tar.gz文件

解壓后修改Makefile文件

在19行添加CROSS_COMPILE=arm-linux-??

注釋12行的COMBINED_BINARY=1，否則不生成udhcpc命令。

3．??建相關配置文件

從busybox的examples/udhcp/下copy??simple.script文件到開發板/usr/share/udhcpc/下，并重命名為default.script，udhcp_0.9.8cvs20050303.orig.tar.gz中也有這樣的文件。

[root@localhost root]# vi usr/share/udhcpc/default.script

#!/bin/sh

?

# udhcpc script edited by Tim Riker <Tim@Rikers.org>

?

[ -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．??重啟開發板，執行udhcpc就可自動獲取IP地址了，以下是執行udhcpc的輸出信息：

?

~ # 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．??如果是雙網卡必須用參數指明

例：udhcpc??-i??eth1?

總結

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