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         int rv;
  85
  86         rv = genl_register_family(&family);
  87         if (rv)
  88                 return rv;
  89
  90         rv = genl_register_ops(&family, &dlm_nl_ops);
  91         if (rv < 0)
  92                 goto err;
  93         return 0;
  94  err:
  95         genl_unregister_family(&family);
  96         return rv;
  97 }
  98
  99 void dlm_netlink_exit(void)
 100 {
 101         genl_unregister_ops(&family, &dlm_nl_ops);
 102         genl_unregister_family(&family);
 103 }
 104
 105 static void fill_data(struct dlm_lock_data *data, struct dlm_lkb *lkb)
 106 {
 107         struct dlm_rsb *r = lkb->lkb_resource;
 108
 109         memset(data, 0, sizeof(struct dlm_lock_data));
 110
 111         data->version = DLM_LOCK_DATA_VERSION;
 112         data->nodeid = lkb->lkb_nodeid;
 113         data->ownpid = lkb->lkb_ownpid;
 114         data->id = lkb->lkb_id;
 115         data->remid = lkb->lkb_remid;
 116         data->status = lkb->lkb_status;
 117         data->grmode = lkb->lkb_grmode;
 118         data->rqmode = lkb->lkb_rqmode;
 119         if (lkb->lkb_ua)
 120                 data->xid = lkb->lkb_ua->xid;
 121         if (r) {
 122                 data->lockspace_id = r->res_ls->ls_global_id;
 123                 data->resource_namelen = r->res_length;
 124                 memcpy(data->resource_name, r->res_name, r->res_length);
 125         }
 126 }
 127
 128 void dlm_timeout_warn(struct dlm_lkb *lkb)
 129 {
 130         struct sk_buff *uninitialized_var(send_skb);
 131         struct dlm_lock_data *data;
 132         size_t size;
 133         int rv;
 134
 135         size = nla_total_size(sizeof(struct dlm_lock_data)) +
 136                nla_total_size(0); /* why this? */
 137
 138         rv = prepare_data(DLM_CMD_TIMEOUT, &send_skb, size);
 139         if (rv < 0)
 140                 return;
 141
 142         data = mk_data(send_skb);
 143         if (!data) {
 144                 nlmsg_free(send_skb);
 145                 return;
 146         }
 147
 148         fill_data(data, lkb);
 149
 150         send_data(send_skb);
 151 }
 152