Mity CPU Platforms » MitySOM-335x (ARM Cortex-A8 Based Products)

Does this distro support the Netlink interface between a kernel module and user space?

I can't get past the initialization. Below is the kernel module code:

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <net/sock.h>
#include <linux/netlink.h>
#include <linux/skbuff.h>
#include <net/net_namespace.h>

#define NETLINK_USER 17

#define MAX_PAYLOAD 1024
struct sock *nl_sk = NULL;

static void nl_recv_msg(struct sk_buff *skb)
{

    struct nlmsghdr *nlh = NULL;
    int pid;

    printk("Entering: %s\n", __FUNCTION__);

    if (skb == NULL)
    {
        printk("skb is NULL \n");
        return;
    }

    nlh = (struct nlmsghdr *)skb->data;
    printk("Netlink received msg payload: %s\n", (char *)nlmsg_data(nlh));
    pid = nlh->nlmsg_pid; /*pid of sending process */
}

int netlink_init(void)
{
    printk("Entering: %s\n", __FUNCTION__);
    nl_sk = netlink_kernel_create(&init_net, NETLINK_USER, 0, nl_recv_msg,
                                  NULL, THIS_MODULE);

    if (!nl_sk)
    {
        printk("Error creating socket.\n");
        return -10;
    }

    return 0;
}

I defined NETLINK_USER in netlink.h, and recompiled and reloaded the kernel. There are no other modifications. netlink_kernel_create() returns NULL. I have found many examples for creating the socket in the kernel, and this version is supposed to work with the 3.2 kernel.

What's wrong?
Mary