fs/dlm/netlink.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Copyright (C) 2007 Red Hat, Inc.  All rights reserved.
0004  */
0005
0006 #include <net/genetlink.h>
0007 #include <linux/dlm.h>
0008 #include <linux/dlm_netlink.h>
0009 #include <linux/gfp.h>
0010
0011 #include "dlm_internal.h"
0012
0013 static uint32_t dlm_nl_seqnum;
0014 static uint32_t listener_nlportid;
0015
0016 static struct genl_family family;
0017
0018 static int prepare_data(u8 cmd, struct sk_buff **skbp, size_t size)
0019 {
0020     struct sk_buff *skb;
0021     void *data;
0022
0023     skb = genlmsg_new(size, GFP_NOFS);
0024     if (!skb)
0025         return -ENOMEM;
0026
0027     /* add the message headers */
0028     data = genlmsg_put(skb, 0, dlm_nl_seqnum++, &family, 0, cmd);
0029     if (!data) {
0030         nlmsg_free(skb);
0031         return -EINVAL;
0032     }
0033
0034     *skbp = skb;
0035     return 0;
0036 }
0037
0038 static struct dlm_lock_data *mk_data(struct sk_buff *skb)
0039 {
0040     struct nlattr *ret;
0041
0042     ret = nla_reserve(skb, DLM_TYPE_LOCK, sizeof(struct dlm_lock_data));
0043     if (!ret)
0044         return NULL;
0045     return nla_data(ret);
0046 }
0047
0048 static int send_data(struct sk_buff *skb)
0049 {
0050     struct genlmsghdr *genlhdr = nlmsg_data((struct nlmsghdr *)skb->data);
0051     void *data = genlmsg_data(genlhdr);
0052
0053     genlmsg_end(skb, data);
0054
0055     return genlmsg_unicast(&init_net, skb, listener_nlportid);
0056 }
0057
0058 static int user_cmd(struct sk_buff *skb, struct genl_info *info)
0059 {
0060     listener_nlportid = info->snd_portid;
0061     printk("user_cmd nlpid %u\n", listener_nlportid);
0062     return 0;
0063 }
0064
0065 static const struct genl_small_ops dlm_nl_ops[] = {
0066     {
0067         .cmd    = DLM_CMD_HELLO,
0068         .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
0069         .doit   = user_cmd,
0070     },
0071 };
0072
0073 static struct genl_family family __ro_after_init = {
0074     .name       = DLM_GENL_NAME,
0075     .version    = DLM_GENL_VERSION,
0076     .small_ops  = dlm_nl_ops,
0077     .n_small_ops    = ARRAY_SIZE(dlm_nl_ops),
0078     .module     = THIS_MODULE,
0079 };
0080
0081 int __init dlm_netlink_init(void)
0082 {
0083     return genl_register_family(&family);
0084 }
0085
0086 void dlm_netlink_exit(void)
0087 {
0088     genl_unregister_family(&family);
0089 }
0090
0091 static void fill_data(struct dlm_lock_data *data, struct dlm_lkb *lkb)
0092 {
0093     struct dlm_rsb *r = lkb->lkb_resource;
0094
0095     memset(data, 0, sizeof(struct dlm_lock_data));
0096
0097     data->version = DLM_LOCK_DATA_VERSION;
0098     data->nodeid = lkb->lkb_nodeid;
0099     data->ownpid = lkb->lkb_ownpid;
0100     data->id = lkb->lkb_id;
0101     data->remid = lkb->lkb_remid;
0102     data->status = lkb->lkb_status;
0103     data->grmode = lkb->lkb_grmode;
0104     data->rqmode = lkb->lkb_rqmode;
0105     if (lkb->lkb_ua)
0106         data->xid = lkb->lkb_ua->xid;
0107     if (r) {
0108         data->lockspace_id = r->res_ls->ls_global_id;
0109         data->resource_namelen = r->res_length;
0110         memcpy(data->resource_name, r->res_name, r->res_length);
0111     }
0112 }
0113
0114 void dlm_timeout_warn(struct dlm_lkb *lkb)
0115 {
0116     struct sk_buff *send_skb;
0117     struct dlm_lock_data *data;
0118     size_t size;
0119     int rv;
0120
0121     size = nla_total_size(sizeof(struct dlm_lock_data)) +
0122            nla_total_size(0); /* why this? */
0123
0124     rv = prepare_data(DLM_CMD_TIMEOUT, &send_skb, size);
0125     if (rv < 0)
0126         return;
0127
0128     data = mk_data(send_skb);
0129     if (!data) {
0130         nlmsg_free(send_skb);
0131         return;
0132     }
0133
0134     fill_data(data, lkb);
0135
0136     send_data(send_skb);
0137 }
0138