谁可以给我最新的netlink编程示例? [英] Who can give me the latest netlink programming samples?

问题描述

我正在编写一个使用netlink在用户空间和内核空间之间进行通信的Linux驱动程序.但是我找不到一些有用的材料，因为netlink已从Linux内核> = 2.6.24更改.谁能给我一些有关如何创建网络链接套接字的建议.预先感谢！

I'm writing a Linux driver using netlink to communicate between user space and kernel space. But I can't find some useful materials, because the netlink has changed from Linux kernel >=2.6.24. Who can give me some suggestions about how to create a netlink socket. Thanks in advance!

推荐答案

下面的代码演示了使用netlink将数据从用户空间应用程序发送到内核模块的基础.此代码在 libnl 的git版本(ef8ba32)的Linux 2.6.28.9上适用.有关更多详细信息，请查看libnl 文档和<广泛使用netlink的href ="http://linuxwireless.org/en/users/Documentation/iw" rel ="noreferrer"> iw .

The code below demonstrates the basics of sending data from a user space application to a kernel module using netlink. This code works on Linux 2.6.28.9 with the git version (ef8ba32) of libnl. For more details, check out the libnl documentation and the code for iw which extensively uses netlink.

内核

#include <linux/kernel.h>
#include <linux/module.h>

#include <net/sock.h>
#include <net/netlink.h>

#define MY_MSG_TYPE (0x10 + 2)  // + 2 is arbitrary. same value for kern/usr

static struct sock *my_nl_sock;

DEFINE_MUTEX(my_mutex);

static int
my_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
{
    int type;
    char *data;

    type = nlh->nlmsg_type;
    if (type != MY_MSG_TYPE) {
        printk("%s: expect %#x got %#x\n", __func__, MY_MSG_TYPE, type);
        return -EINVAL;
    }

    data = NLMSG_DATA(nlh);
    printk("%s: %02x %02x %02x %02x %02x %02x %02x %02x\n", __func__,
            data[0], data[1], data[2], data[3],
            data[4], data[5], data[6], data[7]);
    return 0;
}

static void
my_nl_rcv_msg(struct sk_buff *skb)
{
    mutex_lock(&my_mutex);
    netlink_rcv_skb(skb, &my_rcv_msg);
    mutex_unlock(&my_mutex);
}

static int
my_init(void)
{
    my_nl_sock = netlink_kernel_create(&init_net, NETLINK_USERSOCK, 0,
            my_nl_rcv_msg, NULL, THIS_MODULE);
    if (!my_nl_sock) {
        printk(KERN_ERR "%s: receive handler registration failed\n", __func__);
        return -ENOMEM;
    }

    return 0;
}

static void
my_exit(void)
{
    if (my_nl_sock) {
        netlink_kernel_release(my_nl_sock);
    }
}

module_init(my_init);
module_exit(my_exit);

用户空间

#include <stdio.h>
#include <stdlib.h>

#include <netlink/netlink.h>

#define MY_MSG_TYPE (0x10 + 2)  // + 2 is arbitrary but is the same for kern/usr
int
main(int argc, char *argv[])
{
    struct nl_sock *nls;
    char msg[] = { 0xde, 0xad, 0xbe, 0xef, 0x90, 0x0d, 0xbe, 0xef };
    int ret;

    nls = nl_socket_alloc();
    if (!nls) {
        printf("bad nl_socket_alloc\n");
        return EXIT_FAILURE;
    }

    ret = nl_connect(nls, NETLINK_USERSOCK);
    if (ret < 0) {
        nl_perror(ret, "nl_connect");
        nl_socket_free(nls);
        return EXIT_FAILURE;
    }

    ret = nl_send_simple(nls, MY_MSG_TYPE, 0, msg, sizeof(msg));
    if (ret < 0) {
        nl_perror(ret, "nl_send_simple");
        nl_close(nls);
        nl_socket_free(nls);
        return EXIT_FAILURE;
    } else {
        printf("sent %d bytes\n", ret);
    }

    nl_close(nls);
    nl_socket_free(nls);

    return EXIT_SUCCESS;
}

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