netlink.c

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/*
 * 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 <linux/gfp.h>

#include "dlm_internal.h"

static uint32_t dlm_nl_seqnum;
static uint32_t listener_nlportid;

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_NOFS);
    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(&init_net, skb, listener_nlportid);
}

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

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

int __init dlm_netlink_init(void)
{
    return genl_register_family_with_ops(&family, &dlm_nl_ops, 1);
}

void dlm_netlink_exit(void)
{
    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;
    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 sk_buff *uninitialized_var(send_skb);
    struct dlm_lock_data *data;
    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);
}