cn_test.c

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/*
 *  cn_test.c
 * 
 * 2004+ Copyright (c) Evgeniy Polyakov <[email protected]>
 * All rights reserved.
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#define pr_fmt(fmt) "cn_test: " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/timer.h>

#include <linux/connector.h>

static struct cb_id cn_test_id = { CN_NETLINK_USERS + 3, 0x456 };
static char cn_test_name[] = "cn_test";
static struct sock *nls;
static struct timer_list cn_test_timer;

static void cn_test_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
{
    pr_info("%s: %lu: idx=%x, val=%x, seq=%u, ack=%u, len=%d: %s.\n",
            __func__, jiffies, msg->id.idx, msg->id.val,
            msg->seq, msg->ack, msg->len,
            msg->len ? (char *)msg->data : "");
}

/*
 * Do not remove this function even if no one is using it as
 * this is an example of how to get notifications about new
 * connector user registration
 */
#if 0
static int cn_test_want_notify(void)
{
    struct cn_ctl_msg *ctl;
    struct cn_notify_req *req;
    struct cn_msg *msg = NULL;
    int size, size0;
    struct sk_buff *skb;
    struct nlmsghdr *nlh;
    u32 group = 1;

    size0 = sizeof(*msg) + sizeof(*ctl) + 3 * sizeof(*req);

    size = NLMSG_SPACE(size0);

    skb = alloc_skb(size, GFP_ATOMIC);
    if (!skb) {
        pr_err("failed to allocate new skb with size=%u\n", size);
        return -ENOMEM;
    }

    nlh = nlmsg_put(skb, 0, 0x123, NLMSG_DONE, size - sizeof(*nlh), 0);
    if (!nlh) {
        kfree_skb(skb);
        return -EMSGSIZE;
    }

    msg = nlmsg_data(nlh);

    memset(msg, 0, size0);

    msg->id.idx = -1;
    msg->id.val = -1;
    msg->seq = 0x123;
    msg->ack = 0x345;
    msg->len = size0 - sizeof(*msg);

    ctl = (struct cn_ctl_msg *)(msg + 1);

    ctl->idx_notify_num = 1;
    ctl->val_notify_num = 2;
    ctl->group = group;
    ctl->len = msg->len - sizeof(*ctl);

    req = (struct cn_notify_req *)(ctl + 1);

    /*
     * Idx.
     */
    req->first = cn_test_id.idx;
    req->range = 10;

    /*
     * Val 0.
     */
    req++;
    req->first = cn_test_id.val;
    req->range = 10;

    /*
     * Val 1.
     */
    req++;
    req->first = cn_test_id.val + 20;
    req->range = 10;

    NETLINK_CB(skb).dst_group = ctl->group;
    //netlink_broadcast(nls, skb, 0, ctl->group, GFP_ATOMIC);
    netlink_unicast(nls, skb, 0, 0);

    pr_info("request was sent: group=0x%x\n", ctl->group);

    return 0;
}
#endif

static u32 cn_test_timer_counter;
static void cn_test_timer_func(unsigned long __data)
{
    struct cn_msg *m;
    char data[32];

    pr_debug("%s: timer fired with data %lu\n", __func__, __data);

    m = kzalloc(sizeof(*m) + sizeof(data), GFP_ATOMIC);
    if (m) {

        memcpy(&m->id, &cn_test_id, sizeof(m->id));
        m->seq = cn_test_timer_counter;
        m->len = sizeof(data);

        m->len =
            scnprintf(data, sizeof(data), "counter = %u",
                  cn_test_timer_counter) + 1;

        memcpy(m + 1, data, m->len);

        cn_netlink_send(m, 0, GFP_ATOMIC);
        kfree(m);
    }

    cn_test_timer_counter++;

    mod_timer(&cn_test_timer, jiffies + msecs_to_jiffies(1000));
}

static int cn_test_init(void)
{
    int err;

    err = cn_add_callback(&cn_test_id, cn_test_name, cn_test_callback);
    if (err)
        goto err_out;
    cn_test_id.val++;
    err = cn_add_callback(&cn_test_id, cn_test_name, cn_test_callback);
    if (err) {
        cn_del_callback(&cn_test_id);
        goto err_out;
    }

    setup_timer(&cn_test_timer, cn_test_timer_func, 0);
    mod_timer(&cn_test_timer, jiffies + msecs_to_jiffies(1000));

    pr_info("initialized with id={%u.%u}\n",
        cn_test_id.idx, cn_test_id.val);

    return 0;

      err_out:
    if (nls && nls->sk_socket)
        sock_release(nls->sk_socket);

    return err;
}

static void cn_test_fini(void)
{
    del_timer_sync(&cn_test_timer);
    cn_del_callback(&cn_test_id);
    cn_test_id.val--;
    cn_del_callback(&cn_test_id);
    if (nls && nls->sk_socket)
        sock_release(nls->sk_socket);
}

module_init(cn_test_init);
module_exit(cn_test_fini);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Evgeniy Polyakov <[email protected]>");
MODULE_DESCRIPTION("Connector's test module");