问题描述：

busybox udhcpc获取IP，但没有自动将获取到的ip设置到网卡上，并且没有自动设置网关，路由表等。必须手动设置才能连接外网。

解决方案：

udhcpc可以通过-s参数指定运行脚本，当获取到ip地址后，会自动运行这个脚本，从而自动将获取到的ip地址设置到网卡，并自动设置网关等。脚本的名字没有限制，busybox官网给的脚本如下：

default.script

#!/bin/sh
# udhcpc script edited by Tim Riker <Tim@Rikers.org>RESOLV_CONF="/etc/resolv.conf"[ -n "$1" ] || { echo "Error: should be called from udhcpc"; exit 1; }NETMASK=""
[ -n "$subnet" ] && NETMASK="netmask $subnet"
BROADCAST="broadcast +"
[ -n "$broadcast" ] && BROADCAST="broadcast $broadcast"case "$1" indeconfig)echo "Setting IP address 0.0.0.0 on $interface"busybox ifconfig $interface 0.0.0.0;;renew|bound)echo "Setting IP address $ip on $interface"busybox ifconfig $interface $ip $NETMASK $BROADCASTif [ -n "$router" ] ; thenecho "Deleting routers"while busybox route del default gw 0.0.0.0 dev $interface ; do:donemetric=0for i in $router ; doecho "Adding router $i"busybox route add default gw $i dev $interface metric $metric: $(( metric += 1 ))donefiecho "Recreating $RESOLV_CONF"# If the file is a symlink somewhere (like /etc/resolv.conf# pointing to /run/resolv.conf), make sure things work.realconf=$(readlink -f "$RESOLV_CONF" 2>/dev/null || echo "$RESOLV_CONF")tmpfile="$realconf-$$"> "$tmpfile"[ -n "$domain" ] && echo "search $domain" >> "$tmpfile"for i in $dns ; doecho " Adding DNS server $i"echo "nameserver $i" >> "$tmpfile"donebusybox mv "$tmpfile" "$realconf";;
esacexit 0

最终效果：

root@XXXX:/# busybox udhcpc -i ethsta0 -s /system/bin/default.script
udhcpc: started, v1.26.2
start script
udhcpc: sending discover
udhcpc: sending select for 192.168.247.217
udhcpc: lease of 192.168.247.217 obtained, lease time 3600
start script
start script
deleting routers
route: ioctl 890c: No such process
interface:ethsta0
domain:domain
dns:192.168.247.42
Error connecting (No such file or directory)
Error connecting (No such file or directory)root@XXXX:/ # ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=113 time=116 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=113 time=116 ms
64 bytes from 8.8.8.8: icmp_seq=3 ttl=113 time=139 ms
^C
--- 8.8.8.8 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 1999ms
rtt min/avg/max/mdev = 116.089/124.221/139.793/11.021 ms
root@XXXX:/ #