linux/fs/dlm/netlink.c
Johannes Berg a07ea4d994 genetlink: no longer support using static family IDs
Static family IDs have never really been used, the only
use case was the workaround I introduced for those users
that assumed their family ID was also their multicast
group ID.

Additionally, because static family IDs would never be
reserved by the generic netlink code, using a relatively
low ID would only work for built-in families that can be
registered immediately after generic netlink is started,
which is basically only the control family (apart from
the workaround code, which I also had to add code for so
it would reserve those IDs)

Thus, anything other than GENL_ID_GENERATE is flawed and
luckily not used except in the cases I mentioned. Move
those workarounds into a few lines of code, and then get
rid of GENL_ID_GENERATE entirely, making it more robust.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-27 16:16:09 -04:00

136 lines
2.8 KiB
C

/*
* 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 = {
.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);
genlmsg_end(skb, data);
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);
}
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);
}