fs/dlm/netlink.c

   1 /*
   2  * Copyright (C) 2007 Red Hat, Inc.  All rights reserved.
   3  *
   4  * This copyrighted material is made available to anyone wishing to use,
   5  * modify, copy, or redistribute it subject to the terms and conditions
   6  * of the GNU General Public License v.2.
   7  */
   8
   9 #include <net/genetlink.h>
  10 #include <linux/dlm.h>
  11 #include <linux/dlm_netlink.h>
  12 #include <linux/gfp.h>
  13
  14 #include "dlm_internal.h"
  15
  16 static uint32_t dlm_nl_seqnum;
  17 static uint32_t listener_nlpid;
  18
  19 static struct genl_family family = {
  20         .id             = GENL_ID_GENERATE,
  21         .name           = DLM_GENL_NAME,
  22         .version        = DLM_GENL_VERSION,
  23 };
  24
  25 static int prepare_data(u8 cmd, struct sk_buff **skbp, size_t size)
  26 {
  27         struct sk_buff *skb;
  28         void *data;
  29
  30         skb = genlmsg_new(size, GFP_NOFS);
  31         if (!skb)
  32                 return -ENOMEM;
  33
  34         /* add the message headers */
  35         data = genlmsg_put(skb, 0, dlm_nl_seqnum++, &family, 0, cmd);
  36         if (!data) {
  37                 nlmsg_free(skb);
  38                 return -EINVAL;
  39         }
  40
  41         *skbp = skb;
  42         return 0;
  43 }
  44
  45 static struct dlm_lock_data *mk_data(struct sk_buff *skb)
  46 {
  47         struct nlattr *ret;
  48
  49         ret = nla_reserve(skb, DLM_TYPE_LOCK, sizeof(struct dlm_lock_data));
  50         if (!ret)
  51                 return NULL;
  52         return nla_data(ret);
  53 }
  54
  55 static int send_data(struct sk_buff *skb)
  56 {
  57         struct genlmsghdr *genlhdr = nlmsg_data((struct nlmsghdr *)skb->data);
  58         void *data = genlmsg_data(genlhdr);
  59         int rv;
  60
  61         rv = genlmsg_end(skb, data);
  62         if (rv < 0) {
  63                 nlmsg_free(skb);
  64                 return rv;
  65         }
  66
  67         return genlmsg_unicast(&init_net, skb, listener_nlpid);
  68 }
  69
  70 static int user_cmd(struct sk_buff *skb, struct genl_info *info)
  71 {
  72         listener_nlpid = info->snd_pid;
  73         printk("user_cmd nlpid %u\n", listener_nlpid);
  74         return 0;
  75 }
  76
  77 static struct genl_ops dlm_nl_ops = {
  78         .cmd            = DLM_CMD_HELLO,
  79         .doit           = user_cmd,
  80 };
  81
  82 int __init dlm_netlink_init(void)
  83 {
  84         return genl_register_family_with_ops(&family, &dlm_nl_ops, 1);
  85 }
  86
  87 void dlm_netlink_exit(void)
  88 {
  89         genl_unregister_family(&family);
  90 }
  91
  92 static void fill_data(struct dlm_lock_data *data, struct dlm_lkb *lkb)
  93 {
  94         struct dlm_rsb *r = lkb->lkb_resource;
  95
  96         memset(data, 0, sizeof(struct dlm_lock_data));
  97
  98         data->version = DLM_LOCK_DATA_VERSION;
  99         data->nodeid = lkb->lkb_nodeid;
 100         data->ownpid = lkb->lkb_ownpid;
 101         data->id = lkb->lkb_id;
 102         data->remid = lkb->lkb_remid;
 103         data->status = lkb->lkb_status;
 104         data->grmode = lkb->lkb_grmode;
 105         data->rqmode = lkb->lkb_rqmode;
 106         if (lkb->lkb_ua)
 107                 data->xid = lkb->lkb_ua->xid;
 108         if (r) {
 109                 data->lockspace_id = r->res_ls->ls_global_id;
 110                 data->resource_namelen = r->res_length;
 111                 memcpy(data->resource_name, r->res_name, r->res_length);
 112         }
 113 }
 114
 115 void dlm_timeout_warn(struct dlm_lkb *lkb)
 116 {
 117         struct sk_buff *uninitialized_var(send_skb);
 118         struct dlm_lock_data *data;
 119         size_t size;
 120         int rv;
 121
 122         size = nla_total_size(sizeof(struct dlm_lock_data)) +
 123                nla_total_size(0); /* why this? */
 124
 125         rv = prepare_data(DLM_CMD_TIMEOUT, &send_skb, size);
 126         if (rv < 0)
 127                 return;
 128
 129         data = mk_data(send_skb);
 130         if (!data) {
 131                 nlmsg_free(send_skb);
 132                 return;
 133         }
 134
 135         fill_data(data, lkb);
 136
 137         send_data(send_skb);
 138 }
 139