root/fs/dlm/netlink.c

DEFINITIONS

1. prepare_data
2. mk_data
3. send_data
4. user_cmd
5. dlm_netlink_init
6. dlm_netlink_exit
7. fill_data
8. dlm_timeout_warn

/*
 * Copyright (C) 2007 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License v.2.
 */

#include <net/genetlink.h>
#include <linux/dlm.h>
#include <linux/dlm_netlink.h>

#include "dlm_internal.h"

static uint32_t dlm_nl_seqnum;
static uint32_t listener_nlpid;

static struct genl_family family = {
        .id             = GENL_ID_GENERATE,
        .name           = DLM_GENL_NAME,
        .version        = DLM_GENL_VERSION,
};

static int prepare_data(u8 cmd, struct sk_buff **skbp, size_t size)
{
        struct sk_buff *skb;
        void *data;

        skb = genlmsg_new(size, GFP_KERNEL);
        if (!skb)
                return -ENOMEM;

        /* add the message headers */
        data = genlmsg_put(skb, 0, dlm_nl_seqnum++, &family, 0, cmd);
        if (!data) {
                nlmsg_free(skb);
                return -EINVAL;
        }

        *skbp = skb;
        return 0;
}

static struct dlm_lock_data *mk_data(struct sk_buff *skb)
{
        struct nlattr *ret;

        ret = nla_reserve(skb, DLM_TYPE_LOCK, sizeof(struct dlm_lock_data));
        if (!ret)
                return NULL;
        return nla_data(ret);
}

static int send_data(struct sk_buff *skb)
{
        struct genlmsghdr *genlhdr = nlmsg_data((struct nlmsghdr *)skb->data);
        void *data = genlmsg_data(genlhdr);
        int rv;

        rv = genlmsg_end(skb, data);
        if (rv < 0) {
                nlmsg_free(skb);
                return rv;
        }

        return genlmsg_unicast(skb, listener_nlpid);
}

static int user_cmd(struct sk_buff *skb, struct genl_info *info)
{
        listener_nlpid = info->snd_pid;
        printk("user_cmd nlpid %u\n", listener_nlpid);
        return 0;
}

static struct genl_ops dlm_nl_ops = {
        .cmd            = DLM_CMD_HELLO,
        .doit           = user_cmd,
};

int __init dlm_netlink_init(void)
{
        int rv;

        rv = genl_register_family(&family);
        if (rv)
                return rv;

        rv = genl_register_ops(&family, &dlm_nl_ops);
        if (rv < 0)
                goto err;
        return 0;
 err:
        genl_unregister_family(&family);
        return rv;
}

void dlm_netlink_exit(void)
{
        genl_unregister_ops(&family, &dlm_nl_ops);
        genl_unregister_family(&family);
}

static void fill_data(struct dlm_lock_data *data, struct dlm_lkb *lkb)
{
        struct dlm_rsb *r = lkb->lkb_resource;

        memset(data, 0, sizeof(struct dlm_lock_data));

        data->version = DLM_LOCK_DATA_VERSION;
        data->nodeid = lkb->lkb_nodeid;
        data->ownpid = lkb->lkb_ownpid;
        data->id = lkb->lkb_id;
        data->remid = lkb->lkb_remid;
        data->status = lkb->lkb_status;
        data->grmode = lkb->lkb_grmode;
        data->rqmode = lkb->lkb_rqmode;
        data->timestamp = lkb->lkb_timestamp;
        if (lkb->lkb_ua)
                data->xid = lkb->lkb_ua->xid;
        if (r) {
                data->lockspace_id = r->res_ls->ls_global_id;
                data->resource_namelen = r->res_length;
                memcpy(data->resource_name, r->res_name, r->res_length);
        }
}

void dlm_timeout_warn(struct dlm_lkb *lkb)
{
        struct dlm_lock_data *data;
        struct sk_buff *send_skb;
        size_t size;
        int rv;

        size = nla_total_size(sizeof(struct dlm_lock_data)) +
               nla_total_size(0); /* why this? */

        rv = prepare_data(DLM_CMD_TIMEOUT, &send_skb, size);
        if (rv < 0)
                return;

        data = mk_data(send_skb);
        if (!data) {
                nlmsg_free(send_skb);
                return;
        }

        fill_data(data, lkb);

        send_data(send_skb);
}