fs/dlm/netlink.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2007 Red Hat, Inc.  All rights reserved.
   4  */
   5
   6 #include <net/genetlink.h>
   7 #include <linux/dlm.h>
   8 #include <linux/dlm_netlink.h>
   9 #include <linux/gfp.h>
  10
  11 #include "dlm_internal.h"
  12
  13 static uint32_t dlm_nl_seqnum;
  14 static uint32_t listener_nlportid;
  15
  16 static struct genl_family family;
  17
  18 static int prepare_data(u8 cmd, struct sk_buff **skbp, size_t size)
  19 {
  20         struct sk_buff *skb;
  21         void *data;
  22
  23         skb = genlmsg_new(size, GFP_NOFS);
  24         if (!skb)
  25                 return -ENOMEM;
  26
  27         /* add the message headers */
  28         data = genlmsg_put(skb, 0, dlm_nl_seqnum++, &family, 0, cmd);
  29         if (!data) {
  30                 nlmsg_free(skb);
  31                 return -EINVAL;
  32         }
  33
  34         *skbp = skb;
  35         return 0;
  36 }
  37
  38 static struct dlm_lock_data *mk_data(struct sk_buff *skb)
  39 {
  40         struct nlattr *ret;
  41
  42         ret = nla_reserve(skb, DLM_TYPE_LOCK, sizeof(struct dlm_lock_data));
  43         if (!ret)
  44                 return NULL;
  45         return nla_data(ret);
  46 }
  47
  48 static int send_data(struct sk_buff *skb)
  49 {
  50         struct genlmsghdr *genlhdr = nlmsg_data((struct nlmsghdr *)skb->data);
  51         void *data = genlmsg_data(genlhdr);
  52
  53         genlmsg_end(skb, data);
  54
  55         return genlmsg_unicast(&init_net, skb, listener_nlportid);
  56 }
  57
  58 static int user_cmd(struct sk_buff *skb, struct genl_info *info)
  59 {
  60         listener_nlportid = info->snd_portid;
  61         printk("user_cmd nlpid %u\n", listener_nlportid);
  62         return 0;
  63 }
  64
  65 static const struct genl_small_ops dlm_nl_ops[] = {
  66         {
  67                 .cmd    = DLM_CMD_HELLO,
  68                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
  69                 .doit   = user_cmd,
  70         },
  71 };
  72
  73 static struct genl_family family __ro_after_init = {
  74         .name           = DLM_GENL_NAME,
  75         .version        = DLM_GENL_VERSION,
  76         .small_ops      = dlm_nl_ops,
  77         .n_small_ops    = ARRAY_SIZE(dlm_nl_ops),
  78         .resv_start_op  = DLM_CMD_HELLO + 1,
  79         .module         = THIS_MODULE,
  80 };
  81
  82 int __init dlm_netlink_init(void)
  83 {
  84         return genl_register_family(&family);
  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 *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