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
  13 #include "dlm_internal.h"
  14
  15 static uint32_t dlm_nl_seqnum;
  16 static uint32_t listener_nlpid;
  17
  18 static struct genl_family family = {
  19         .id             = GENL_ID_GENERATE,
  20         .name           = DLM_GENL_NAME,
  21         .version        = DLM_GENL_VERSION,
  22 };
  23
  24 static int prepare_data(u8 cmd, struct sk_buff **skbp, size_t size)
  25 {
  26         struct sk_buff *skb;
  27         void *data;
  28
  29         skb = genlmsg_new(size, GFP_KERNEL);
  30         if (!skb)
  31                 return -ENOMEM;
  32
  33         /* add the message headers */
  34         data = genlmsg_put(skb, 0, dlm_nl_seqnum++, &family, 0, cmd);
  35         if (!data) {
  36                 nlmsg_free(skb);
  37                 return -EINVAL;
  38         }
  39
  40         *skbp = skb;
  41         return 0;
  42 }
  43
  44 static struct dlm_lock_data *mk_data(struct sk_buff *skb)
  45 {
  46         struct nlattr *ret;
  47
  48         ret = nla_reserve(skb, DLM_TYPE_LOCK, sizeof(struct dlm_lock_data));
  49         if (!ret)
  50                 return NULL;
  51         return nla_data(ret);
  52 }
  53
  54 static int send_data(struct sk_buff *skb)
  55 {
  56         struct genlmsghdr *genlhdr = nlmsg_data((struct nlmsghdr *)skb->data);
  57         void *data = genlmsg_data(genlhdr);
  58         int rv;
  59
  60         rv = genlmsg_end(skb, data);
  61         if (rv < 0) {
  62                 nlmsg_free(skb);
  63                 return rv;
  64         }
  65
  66         return genlmsg_unicast(skb, listener_nlpid);
  67 }
  68
  69 static int user_cmd(struct sk_buff *skb, struct genl_info *info)
  70 {
  71         listener_nlpid = info->snd_pid;
  72         printk("user_cmd nlpid %u\n", listener_nlpid);
  73         return 0;
  74 }
  75
  76 static struct genl_ops dlm_nl_ops = {
  77         .cmd            = DLM_CMD_HELLO,
  78         .doit           = user_cmd,
  79 };
  80
  81 int dlm_netlink_init(void)
  82 {
  83         int rv;
  84
  85         rv = genl_register_family(&family);
  86         if (rv)
  87                 return rv;
  88
  89         rv = genl_register_ops(&family, &dlm_nl_ops);
  90         if (rv < 0)
  91                 goto err;
  92         return 0;
  93  err:
  94         genl_unregister_family(&family);
  95         return rv;
  96 }
  97
  98 void dlm_netlink_exit(void)
  99 {
 100         genl_unregister_ops(&family, &dlm_nl_ops);
 101         genl_unregister_family(&family);
 102 }
 103
 104 static void fill_data(struct dlm_lock_data *data, struct dlm_lkb *lkb)
 105 {
 106         struct dlm_rsb *r = lkb->lkb_resource;
 107         struct dlm_user_args *ua = (struct dlm_user_args *) lkb->lkb_astparam;
 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         data->timestamp = lkb->lkb_timestamp;
 120         if (ua)
 121                 data->xid = ua->xid;
 122         if (r) {
 123                 data->lockspace_id = r->res_ls->ls_global_id;
 124                 data->resource_namelen = r->res_length;
 125                 memcpy(data->resource_name, r->res_name, r->res_length);
 126         }
 127 }
 128
 129 void dlm_timeout_warn(struct dlm_lkb *lkb)
 130 {
 131         struct dlm_lock_data *data;
 132         struct sk_buff *send_skb;
 133         size_t size;
 134         int rv;
 135
 136         size = nla_total_size(sizeof(struct dlm_lock_data)) +
 137                nla_total_size(0); /* why this? */
 138
 139         rv = prepare_data(DLM_CMD_TIMEOUT, &send_skb, size);
 140         if (rv < 0)
 141                 return;
 142
 143         data = mk_data(send_skb);
 144         if (!data) {
 145                 nlmsg_free(send_skb);
 146                 return;
 147         }
 148
 149         fill_data(data, lkb);
 150
 151         send_data(send_skb);
 152 }
 153