#include <sys/socket.h>
#include >linux/netlink.h>
#define NETLINK_TEST 17
#define MAX_PAYLOAD 1024

struct sockaddr_nl src_addr, dest_addr;
struct msghdr msg;
struct nlmsghdr *nlh = NULL;
struct iovec iov;
int sock_fd;
int sent;


int main() 
{
        sock_fd = socket(PF_NETLINK, SOCK_RAW,NETLINK_TEST);
        memset(&src_addr, 0, sizeof(src_addr));
        src_addr.nl_family = AF_NETLINK;      
        src_addr.nl_pid = getpid();  
        src_addr.nl_groups = 0;  
        bind(sock_fd, (struct sockaddr*)&src_addr, sizeof(src_addr));
        memset(&dest_addr, 0, sizeof(dest_addr));
        dest_addr.nl_family = AF_NETLINK;
        dest_addr.nl_pid = 0;   
        dest_addr.nl_groups = 0; 
        nlh=(struct nlmsghdr *)malloc(NLMSG_SPACE(MAX_PAYLOAD));

        nlh->nlmsg_len = NLMSG_SPACE(MAX_PAYLOAD);
        nlh->nlmsg_pid = getpid();  
        nlh->nlmsg_flags = 0;
        strcpy(NLMSG_DATA(nlh), "Hello from userspace!\n\0");
        iov.iov_base = (void *)nlh;
        iov.iov_len = nlh->nlmsg_len;
        msg.msg_name = (void *)&dest_addr;
        msg.msg_namelen = sizeof(dest_addr);
        msg.msg_iov = &iov;
        msg.msg_iovlen = 1;
        if ((sent = sendmsg(sock_fd, &msg, 0)) >= 0)
        {
                printf("%d characters sent.\n", sent);
        }
        else
        {
                perror("Send error");
        }
        close(sock_fd);
        return 0;
}

#include <linux/config.h>
#include <linux/socket.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netlink.h>
#include <net/sock.h>

#define NETLINK_TEST 17
#define MAX_PAYLOAD 1024

static struct sock *nl_sk;

void input(struct sock *sk, int len)
{
        struct sk_buff *skb = NULL;
        struct nlmsghdr *nlh = NULL;
        u8 *payload = NULL;
        u32 pid = 0;
        while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) 
        {
                nlh = (struct nlmsghdr *)skb->data;
                payload = NLMSG_DATA(nlh);
                printk("%s: received netlink message payload:%s\n", __FUNCTION__, payload);
        }
}

static int __init my_module_init(void)
{
        int err;
        struct sk_buff *skb;
        struct nlmsghdr *nlh = NULL;
        nl_sk = netlink_kernel_create(NETLINK_TEST, input);
        return (nl_sk !=0);
}

static void __exit my_module_exit(void)
{
        sock_release(nl_sk->sk_socket);
}

module_init(my_module_init);
module_exit(my_module_exit);