求助:netlink 中 netlink_kernel_create()中的回调INPUT

Fart_King

这个回调函数总是不调用 netlink_kernel_create()函数已经返回socket成功。
但挂载模块后 INPUT这个回调 总不调用。

代码:

void input(struct sock *sk, int nlen)
{
        printk("\n\nIs Enter CALLBACK FUNCTION \n");
        if ( !p_content )
        {
                printk("p_content is null \n");
                return;
        }
        struct sk_buff *skb;
  struct nlmsghdr *nlh;
  u32 pid;
  int rc, err;
  int len = NLMSG_SPACE(1200);
  char str[100];
  printk("net_link: data is ready to read.\n");
  skb = skb_recv_datagram(nl_sk, 0, 0, &err);
  if (skb->len >= NLMSG_SPACE(0)) {
    nlh = nlmsg_hdr(skb);
    printk("net_link: recv %s.\n", (char *)NLMSG_DATA(nlh));
    memcpy(str,NLMSG_DATA(nlh), sizeof(str));
    pid = nlh->nlmsg_pid;    //pid of sending process
    printk("net_link: pid is %d\n", pid);
    kfree_skb(skb);
    skb = alloc_skb(len, GFP_ATOMIC);
    if (!skb){
      printk(KERN_ERR "net_link: allocate failed.\n");
      return;
    }
    nlh = nlmsg_put(skb,0,0,0,1200,0);
    NETLINK_CB(skb).pid = 0; // from kernel
    memcpy(NLMSG_DATA(nlh), p_content, sizeof(p_content));
   
    printk("net_link: going to send.\n");
    rc = netlink_unicast(nl_sk, skb, pid, MSG_DONTWAIT);
    memset(p_content, 0, 1024);
    if (rc < 0) {
      printk(KERN_ERR "net_link: can not unicast skb (%d)\n", rc);
    }
    printk("net_link: send is ok.\n");
  }
}


static int test_netlink(void) {
  nl_sk = netlink_kernel_create( &init_net, NETLINK_TEST, 0, input, NULL, THIS_MODULE);
  if (!nl_sk) {
    printk(KERN_ERR "net_link: Cannot create netlink socket.\n");
    return -EIO;
  }
  printk("net_link: create socket ok.\n");
  return 0;
}