iwpriv工具通过ioctl动态获取相应无线网卡驱动的(3)

发布时间:2021-06-11

"qstats"
"txpktstats"
"getcfptable"
"mefcfg"
"getmem"
};







浅析ethx网卡控制函数ioctl实现具体流程

====================
1.应用层程序iwpriv
wireless tools网络配置应用程序iwpriv命令格式:
iwpriv ethX private-command [parameters]

iwpriv部分实现源码如下:
int main(int argc, char *argv[])
{
...
sockfd = socket(AF_INET, SOCK_STREAM, 0);
...
ioctl(sockfd, ioctl_val, &iwr);//将控制命令通过ioctl发送到无线网卡
...
}
====================
2.系统调用sys_ioctl
应用层通过ioctl(sockfd, ioctl_val, &iwr);触发sys_ioctl系统调用,实际流程:
sys_ioctl=>vfs_ioctl=>do_ioctl=最后调用
filp->f_op->unlocked_ioctl执行具体的ioctl操作,该操作就是sock_ioctl,至于为什么是sock_ioctl,后边作了进一步分析
sock_ioctl=>
{
...
#ifdef CONFIG_WIRELESS_EXT
if (cmd >= SIOCIWFIRST && cmd <= SIOCIWLAST) {
err = dev_ioctl(net, cmd, argp);//

} else
#endif
...
}
dev_ioctl=>wext_handle_ioctl
{
...
/* Take care of Wireless Extensions */
if (cmd >= SIOCIWFIRST && cmd <= SIOCIWLAST)
return wext_handle_ioctl(net, &ifr, cmd, arg);
...
}
wext_handle_ioctl=>wireless_process_ioctl=>
然后通过if ((dev = __dev_get_by_name(net, ifr->ifr_name)) == NULL)函数,
从系统管理的net链表中,把ioctl指定的ethX对应的struct net_device摘出来,
最后调用ioctl_private_call(handler)或者调用dev->do_ioctl(dev, ifr, cmd)来处理该ioctl,
这两个函数分别指向wlan_handler_def和wlan_do_ioctl
====================
3.wifi网卡是怎么登记到kernel上的
wlan_probe()=>wlan_add_card()=>alloc_etherdev()=>
之后将操作方法添加到struct net_device *dev=alloc_etherdev()申请的dev上去,其中包括:
...
/* Setup the OS Interface to our functions */
dev->open = wlan_open;
dev->hard_start_xmit = wlan_hard_start_xmit;
dev->stop = wlan_close;
dev->do_ioctl = wlan_do_ioctl;
dev->set_mac_address = wlan_set_mac_address;

dev->tx_timeout = wlan_tx_timeout;
dev->get_stats = wlan_get_stats;
dev->watchdog_timeo = MRVDRV_DEFAULT_WATCHDOG_TIMEOUT;
dev->wireless_handlers = (struct iw_handler_def *) &wlan_handler_def;
dev->set_multicast_list = wlan_set_multicast_list;
...
4.socket系统调用如何关联上ioctl和ethX设备

asmlinkage long sys_socket(int family, int type, int protocol);

sys_socket=>sock_create=>__sock_create=>sock = sock_alloc();通过sock_mnt->mnt_sb从socket文件系统的超级块上申请一个inode节点,这样也就同时获得了由该inode描述的一个sock结构体单元,所以sokcet和dentry目录项等效,
接下来从net_families全局管理结构体中找到当
前family对应的ops操作集,
net_proto_family *pf=net_families[family];
pf->create(net, sock, protocol);//核心调用,对于ipv4,就是inet_create
以ipv4为例
static s

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