浅析ethx网卡控制函数ioctl实现具体流程
2014-01-07 19:39
525 查看
==================== 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 struct net_proto_family inet_family_ops = { .family = PF_INET, .create = inet_create, .owner = THIS_MODULE, }; 还记得上面应用层创建sokcet的函数吧, sockfd = socket(AF_INET, SOCK_STREAM, 0);//AF_INET虽然等于PF_INET,但是因为种种原因我们提倡使用PF_INET 可见family等于AF_INET,type等于SOCK_STREAM,协议protocol为0,也就是采用IP协议, inet_create=>inetsw[sock->type]也就是inetsw[SOCK_STREAM], 从inetsw[sock->type]中找到已经登记的protocol网络协议处理函数, inetsw[]是怎么填充的呢?inet_init()=>inet_register_protosw(inetsw_array)=>这样inetsw_array中的所有protocol处理模块都将登记到inetsw中了, static struct inet_protosw inetsw_array[] = { { .type = SOCK_STREAM, .protocol = IPPROTO_TCP, .prot = &tcp_prot, .ops = &inet_stream_ops, .capability = -1, .no_check = 0, .flags = INET_PROTOSW_PERMANENT | INET_PROTOSW_ICSK, },
{ .type = SOCK_DGRAM, .protocol = IPPROTO_UDP, .prot = &udp_prot, .ops = &inet_dgram_ops, .capability = -1, .no_check = UDP_CSUM_DEFAULT, .flags = INET_PROTOSW_PERMANENT, },
{ .type = SOCK_RAW, .protocol = IPPROTO_IP, /* wild card */ .prot = &raw_prot, .ops = &inet_sockraw_ops, .capability = CAP_NET_RAW, .no_check = UDP_CSUM_DEFAULT, .flags = INET_PROTOSW_REUSE, } }; 至于inet_init,则是以fs_initcall(inet_init)方式,以5号优先级被build in到了内核中,当kernel启动时会在start_kernel=>rest_init=>kernel_init=>do_basic_setup=>do_initcalls中依据优先级号优先于其他module驱动被调用. 这样sock->ops = answer->ops;对于ipv4也就等于inet_stream_ops, 接下来就是将ops填充到file操作指针中了, sys_socket=>sock_map_fd=>sock_attach_fd=> dentry->d_op = &sockfs_dentry_operations; init_file(file, sock_mnt, dentry, FMODE_READ | FMODE_WRITE, &socket_file_ops); file->private_data = sock; 其中init_file=>file->f_op = fop;也就是file->f_op = socket_file_ops; 所以read(),wirte(),poll()和ioctl()应用程序调用的file->f_op就是socket_file_ops了, 比如: read()对应sock_aio_read网络异步读 write()对应sock_aio_write网络异步写 ioctl()对应sock_ioctl
socket_file_ops结构体具体实现如下: static const struct file_operations socket_file_ops = { .owner = THIS_MODULE, .llseek = no_llseek, .aio_read = sock_aio_read, .aio_write = sock_aio_write, .poll = sock_poll, .unlocked_ioctl = sock_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = compat_sock_ioctl, #endif .mmap = sock_mmap, .open = sock_no_open, /* special open code to disallow open via /proc */ .release = sock_close, .fasync = sock_fasync, .sendpage = sock_sendpage, .splice_write = generic_splice_sendpage, }; 网卡控制因为涉及到的知识点比较多,上面只是从宏观上对数据流程做了一个简单的介绍,深入到其中的每个知识点,都会牵扯出一系列文章,读者需要自己去一个个的慢慢深入,希望本文能够对刚刚接触网络驱动的读者有所帮助和启发【gliethttp.Leith】
wireless extention扩展接口Blog作者的回复: wlan_add_card=> wlan_create_thread(wlan_service_main_thread, &priv->MainThread, "wlan_main_service"); =>wlan_service_main_thread=>wlan_exec_next_cmd=> 将调用wlan_enter_ps和wlan_exit_ps
sbi_interrupt=>从sdio口上传来的中断数据,sdio_irq_thread=>process_sdio_pending_irqs=>调用func->irq_handler(func);即本. 在mmc_signal_sdio_irq=>将调用wake_up_process(host->sdio_irq_thread);来唤醒该irq处理线程,可能还有其他命令需要处理wlan_exec_next_cmd 这个pxamci_irq就是mmc的物理irq中断了,pxamci_irq=>mmc_signal_sdio_irq(host->mmc);
wlan_exec_next_cmd=>只要cmd链表上CmdNode还存在, 那么就会执行wlan_dnld_cmd_to_fw(wlan_private * priv, CmdCtrlNode * CmdNode)将CmdNode中的数据下发下去, 然后重新触发wlan_mod_timer(&Adapter->MrvDrvCommandTimer, MRVDRV_TIMER_5S); 也就是wlan_cmd_timeout_func命令超时处理函数, 在cmd已经有了恢复之后,在主线程中调用wlan_process_cmdresp,立即调用wlan_cancel_timer(&Adapter->MrvDrvCommandTimer);来删除定时器
wlan_service_main_thread=>每次唤醒都会检查 ==== /* Execute the next command */ if (!priv->wlan_dev.cmd_sent && !Adapter->CurCmd) wlan_exec_next_cmd(priv); ====
wlan_prepare_cmd=> wlan_hostcmd_ioctl=> 获取一个空闲的CmdNode节点wlan_get_cmd_node,当完成赋值之后,执行如下语句,将CmdNode节点添加到处理队列中: wlan_insert_cmd_to_pending_q(Adapter, CmdNode, TRUE); wake_up_interruptible(&priv->MainThread.waitQ); 另外在数组中 /* * iwconfig settable callbacks */ static const iw_handler wlan_handler[]这个数组中全部是回调函数,
/** wlan_handler_def */ struct iw_handler_def wlan_handler_def = { num_standard:sizeof(wlan_handler) / sizeof(iw_handler), num_private:sizeof(wlan_private_handler) / sizeof(iw_handler), num_private_args:sizeof(wlan_private_args) / sizeof(struct iw_priv_args), standard:(iw_handler *) wlan_handler, private:(iw_handler *) wlan_private_handler, private_args:(struct iw_priv_args *) wlan_private_args, #if WIRELESS_EXT > 20 get_wireless_stats:wlan_get_wireless_stats, #endif }; 在wlan_add_card函数中 dev->wireless_handlers = (struct iw_handler_def *) &wlan_handler_def;
===============在kernel的net中使用wireless extention扩展接口
static iw_handler get_handler(struct net_device *dev, unsigned int cmd) { /* Don't "optimise" the following variable, it will crash */ unsigned int index; /* *MUST* be unsigned */
/* Check if we have some wireless handlers defined */ if (dev->wireless_handlers == NULL) return NULL;
/* Try as a standard command */ index = cmd - SIOCIWFIRST; if (index < dev->wireless_handlers->num_standard) return dev->wireless_handlers->standard[index];
/* Try as a private command */ index = cmd - SIOCIWFIRSTPRIV; if (index < dev->wireless_handlers->num_private) return dev->wireless_handlers->private[index];
/* Not found */ return NULL; }
=>sock_ioctl =>dev_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(struct net *net, struct ifreq *ifr, unsigned int cmd) =>get_handler(dev, cmd);如果没有实现该cmd,那么将调用dev->do_ioctl来处理,
wlan_reassoc_timer_func=> wmm_start_queue=> wlan_tx_packet=> wlan_tx_timeout=> wlan_remove_card=> wlan_hostcmd_ioctl=> wlan_auto_deep_sleep=> wlan_set_deep_sleep=> wlan_prepare_cmd=> wlan_cmd_timeout_func=> 将调用wake_up_interruptible(&priv->MainThread.waitQ);唤醒wlan_service_main_thread主处理线程.
wlan_hard_start_xmit=>wlan_tx_packet发送数据包 dev->tx_timeout = wlan_tx_timeout; wlan_initialize_timer(&Adapter->MrvDrvCommandTimer, wlan_cmd_timeout_func, priv);
int wlan_do_ioctl(struct net_device *dev, struct ifreq *req, int cmd) { ... case WLAN_WAKEUP_MT: if (wrq->u.data.length > 0) Adapter->IntCounter++; wake_up_interruptible(&priv->MainThread.waitQ); break; ... }
在wlan_process_cmdresp()处理完该cmd之后,调用 wlan_insert_cmd_to_free_q=>wlan_clean_cmd_noder,从命令链表上删除已经处理完成的cmd_node, wlan_clean_cmd_noder然后pTempNode->CmdWaitQWoken = TRUE;同时如果该cmd_node是一个被阻塞等待的,那么唤醒等待的程序. wake_up_interruptible(&pTempNode->cmdwait_q);
相关文章推荐
- android混淆打包经验分享!+自己体会
- Oracle-07445[kgghash]:Oracle BUG导致更新LOB字段时进程被KILL掉
- PHP解析Android APK包的XML文件
- Linux常用编程工具之ld连接器简介
- java面试中有关多线程的试题
- PowerDesigner中如何生成主键和自增列--Oracle版本
- 免信用卡注册美国App Store账号
- js阿拉伯数字转中文大写
- ThreadLocal
- APR(Apache Portable Run-time Librarie)介绍
- 加多宝首度披露"换头手术"的详细内幕
- HDU4708
- 数据结构②-栈
- 加多宝首度披露"换头手术"的详细内幕
- Apache中的进程剖析(4)
- Oracle密码过期the password has expired解决办法
- MyDNS安装
- CodeIngniter form_open()的一个问题
- Apache中的进程剖析(3)
- JNI_OnLoad returned bad version (-1) 问题解决 proguard