[root@(none) tmp]# iwlist wlan0 scan | grep ESSID
fwdbg: get survey cmd
fwdbg: survey done (00000005, 00000000)
ESSID: "TPLINK_WSW"
ESSID: "TPLINK_717E24"
ESSID: "dlink"
ESSID: "newnav"
ESSID: "dgdz"
(5) 配置wlan0的SSID
iwconfig wlan essid TPLINK_717E24
配置成功后利用iwconfig回显：
[root@(none) tmp]# uname a
Linux (none) 2.6.12h1940 #59 Tue May 3 13:12:53 CST 2011 armv4tl unknown
[root@(none) tmp]# iwconfig wlan0
wlan0IEEE 802.11bg ESSID:"TPLINK_717E24"
Mode: Managed Frequency: 2.437 GHz ACCess Point: 00:25:86:71:7E:24
Bit Rate: 54 Mb/s
Encryption key:off
Power Management: off
Link Quality=52/100 Signal level=52/100 Noise level=0/100
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
(6) IP动态分配
自动申请动态IP：
udhcpc i wlan0
显示如下信息：
[root@(none) tmp]# uname a
Linux (none) 2.6.12h1940 #59 Tue May 3 13:12:53 CST 2011 armv4tl unknown
[root@(none) tmp]# udhcpc i wlan0
udhcpc (v0.9.9pre) started
udhcpc[490]: udhcpc (v0.9.9pre) started
Sending discover...
udhcpc[490]: Sending discover...
Sending select for 172.16.51.9...
udhcpc[490]: Sending select for 172.16.51.9...
Lease of 172.16.51.9 obtained, lease time 691200
udhcpc[490]: Lease of 172.16.51.9 obtained, lease time 691200
deleting routers
route: SIOC[ADD|DEL]RT: No such process
adding dns 61.153.216.99
adding dns 61.153.216.104
运行ifconfig命令后，显示最终配置：
[root@(none) tmp]# uname a
Linux (none) 2.6.12h1940 #59 Tue May 3 13:12:53 CST 2011 armv4tl unknown
[root@(none) tmp]# ifconfig wlan0
wlan0 Line encap: Ethernet HWaddr 00:0F:10:54:0E:1B
inet addr: 172.16.51.9 Bcast:172.16.255.255 Mask: 255.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX PACkets:618 errors:0 dropped:0 overruns:0 frame:0
TX packets:2 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
(7) PINg测试
ping测试时需要加c参数控制ping次数，否则会一直不停测试，并且无法kill。
[root@(none) tmp]# ping c 2 172.16.51.9
PING 172.16.51.9 (172.16.51.9): 56 data bytes
64 bytes from 172.16.51.9: icmp_seq=0 ttl=64 time=1.4 ms
64 bytes from 172.16.51.9: icmp_seq=1 ttl=64 time=0.7 ms
---172.16.51.9 ping statistics
2 packets transmitted, 2 packets received, 0% packet loss
roundtrip min/avg/max=0.7/1.0/1.4 ms
3 讨论
在USB无线网卡驱动移植过程中，将主要的文件netdevice.h、wireless.h、iw_handler.h、dev.c等进行替换后，内核已经能编译成功。将内核下载并重启开发板后，加载驱动成功，并能利用iwlist搜索到周边的WLAN网络。在利用iwconfig给驱动指定SSID时iwconfig引起内核崩溃。初判原因不应为wirelesstools程序。加入ip.h、icmp.h socket.h等文件后iwconfig指定SSID成功。最后进行ping测试时，出现ping 127.1和本机IP均失败的情况。使用strace跟踪ping执行过程，发现recvfrom()函数参数传递错误，替换neighbour.c af_netlink.c等文件后ping 127.1成功。
若系统内核升级到Linux 2.6.30，驱动能编译通过，但只要一发出ifconfig命令，内核即崩溃。即使高版本内核在移植时也有问题，这些问题需要进一步研究。
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