net/netfilter/nfnetlink_cttimeout.c

   1 /*
   2  * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org>
   3  * (C) 2012 by Vyatta Inc. <http://www.vyatta.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation (or any later at your option).
   8  */
   9 #include <linux/init.h>
  10 #include <linux/module.h>
  11 #include <linux/kernel.h>
  12 #include <linux/rculist.h>
  13 #include <linux/rculist_nulls.h>
  14 #include <linux/types.h>
  15 #include <linux/timer.h>
  16 #include <linux/security.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/errno.h>
  19 #include <linux/netlink.h>
  20 #include <linux/spinlock.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/slab.h>
  23
  24 #include <linux/netfilter.h>
  25 #include <net/netlink.h>
  26 #include <net/sock.h>
  27 #include <net/netfilter/nf_conntrack.h>
  28 #include <net/netfilter/nf_conntrack_core.h>
  29 #include <net/netfilter/nf_conntrack_l3proto.h>
  30 #include <net/netfilter/nf_conntrack_l4proto.h>
  31 #include <net/netfilter/nf_conntrack_tuple.h>
  32 #include <net/netfilter/nf_conntrack_timeout.h>
  33
  34 #include <linux/netfilter/nfnetlink.h>
  35 #include <linux/netfilter/nfnetlink_cttimeout.h>
  36
  37 MODULE_LICENSE("GPL");
  38 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
  39 MODULE_DESCRIPTION("cttimeout: Extended Netfilter Connection Tracking timeout tuning");
  40
  41 static const struct nla_policy cttimeout_nla_policy[CTA_TIMEOUT_MAX+1] = {
  42         [CTA_TIMEOUT_NAME]      = { .type = NLA_NUL_STRING,
  43                                     .len  = CTNL_TIMEOUT_NAME_MAX - 1},
  44         [CTA_TIMEOUT_L3PROTO]   = { .type = NLA_U16 },
  45         [CTA_TIMEOUT_L4PROTO]   = { .type = NLA_U8 },
  46         [CTA_TIMEOUT_DATA]      = { .type = NLA_NESTED },
  47 };
  48
  49 static int
  50 ctnl_timeout_parse_policy(void *timeouts,
  51                           const struct nf_conntrack_l4proto *l4proto,
  52                           struct net *net, const struct nlattr *attr)
  53 {
  54         struct nlattr **tb;
  55         int ret = 0;
  56
  57         if (!l4proto->ctnl_timeout.nlattr_to_obj)
  58                 return 0;
  59
  60         tb = kcalloc(l4proto->ctnl_timeout.nlattr_max + 1, sizeof(*tb),
  61                      GFP_KERNEL);
  62
  63         if (!tb)
  64                 return -ENOMEM;
  65
  66         ret = nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max, attr,
  67                                l4proto->ctnl_timeout.nla_policy, NULL);
  68         if (ret < 0)
  69                 goto err;
  70
  71         ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, net, timeouts);
  72
  73 err:
  74         kfree(tb);
  75         return ret;
  76 }
  77
  78 static int cttimeout_new_timeout(struct net *net, struct sock *ctnl,
  79                                  struct sk_buff *skb,
  80                                  const struct nlmsghdr *nlh,
  81                                  const struct nlattr * const cda[],
  82                                  struct netlink_ext_ack *extack)
  83 {
  84         __u16 l3num;
  85         __u8 l4num;
  86         const struct nf_conntrack_l4proto *l4proto;
  87         struct ctnl_timeout *timeout, *matching = NULL;
  88         char *name;
  89         int ret;
  90
  91         if (!cda[CTA_TIMEOUT_NAME] ||
  92             !cda[CTA_TIMEOUT_L3PROTO] ||
  93             !cda[CTA_TIMEOUT_L4PROTO] ||
  94             !cda[CTA_TIMEOUT_DATA])
  95                 return -EINVAL;
  96
  97         name = nla_data(cda[CTA_TIMEOUT_NAME]);
  98         l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO]));
  99         l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]);
 100
 101         list_for_each_entry(timeout, &net->nfct_timeout_list, head) {
 102                 if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
 103                         continue;
 104
 105                 if (nlh->nlmsg_flags & NLM_F_EXCL)
 106                         return -EEXIST;
 107
 108                 matching = timeout;
 109                 break;
 110         }
 111
 112         if (matching) {
 113                 if (nlh->nlmsg_flags & NLM_F_REPLACE) {
 114                         /* You cannot replace one timeout policy by another of
 115                          * different kind, sorry.
 116                          */
 117                         if (matching->l3num != l3num ||
 118                             matching->l4proto->l4proto != l4num)
 119                                 return -EINVAL;
 120
 121                         return ctnl_timeout_parse_policy(&matching->data,
 122                                                          matching->l4proto, net,
 123                                                          cda[CTA_TIMEOUT_DATA]);
 124                 }
 125
 126                 return -EBUSY;
 127         }
 128
 129         l4proto = nf_ct_l4proto_find_get(l3num, l4num);
 130
 131         /* This protocol is not supportted, skip. */
 132         if (l4proto->l4proto != l4num) {
 133                 ret = -EOPNOTSUPP;
 134                 goto err_proto_put;
 135         }
 136
 137         timeout = kzalloc(sizeof(struct ctnl_timeout) +
 138                           l4proto->ctnl_timeout.obj_size, GFP_KERNEL);
 139         if (timeout == NULL) {
 140                 ret = -ENOMEM;
 141                 goto err_proto_put;
 142         }
 143
 144         ret = ctnl_timeout_parse_policy(&timeout->data, l4proto, net,
 145                                         cda[CTA_TIMEOUT_DATA]);
 146         if (ret < 0)
 147                 goto err;
 148
 149         strcpy(timeout->name, nla_data(cda[CTA_TIMEOUT_NAME]));
 150         timeout->l3num = l3num;
 151         timeout->l4proto = l4proto;
 152         refcount_set(&timeout->refcnt, 1);
 153         list_add_tail_rcu(&timeout->head, &net->nfct_timeout_list);
 154
 155         return 0;
 156 err:
 157         kfree(timeout);
 158 err_proto_put:
 159         nf_ct_l4proto_put(l4proto);
 160         return ret;
 161 }
 162
 163 static int
 164 ctnl_timeout_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
 165                        int event, struct ctnl_timeout *timeout)
 166 {
 167         struct nlmsghdr *nlh;
 168         struct nfgenmsg *nfmsg;
 169         unsigned int flags = portid ? NLM_F_MULTI : 0;
 170         const struct nf_conntrack_l4proto *l4proto = timeout->l4proto;
 171
 172         event = nfnl_msg_type(NFNL_SUBSYS_CTNETLINK_TIMEOUT, event);
 173         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
 174         if (nlh == NULL)
 175                 goto nlmsg_failure;
 176
 177         nfmsg = nlmsg_data(nlh);
 178         nfmsg->nfgen_family = AF_UNSPEC;
 179         nfmsg->version = NFNETLINK_V0;
 180         nfmsg->res_id = 0;
 181
 182         if (nla_put_string(skb, CTA_TIMEOUT_NAME, timeout->name) ||
 183             nla_put_be16(skb, CTA_TIMEOUT_L3PROTO, htons(timeout->l3num)) ||
 184             nla_put_u8(skb, CTA_TIMEOUT_L4PROTO, timeout->l4proto->l4proto) ||
 185             nla_put_be32(skb, CTA_TIMEOUT_USE,
 186                          htonl(refcount_read(&timeout->refcnt))))
 187                 goto nla_put_failure;
 188
 189         if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) {
 190                 struct nlattr *nest_parms;
 191                 int ret;
 192
 193                 nest_parms = nla_nest_start(skb,
 194                                             CTA_TIMEOUT_DATA | NLA_F_NESTED);
 195                 if (!nest_parms)
 196                         goto nla_put_failure;
 197
 198                 ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, &timeout->data);
 199                 if (ret < 0)
 200                         goto nla_put_failure;
 201
 202                 nla_nest_end(skb, nest_parms);
 203         }
 204
 205         nlmsg_end(skb, nlh);
 206         return skb->len;
 207
 208 nlmsg_failure:
 209 nla_put_failure:
 210         nlmsg_cancel(skb, nlh);
 211         return -1;
 212 }
 213
 214 static int
 215 ctnl_timeout_dump(struct sk_buff *skb, struct netlink_callback *cb)
 216 {
 217         struct net *net = sock_net(skb->sk);
 218         struct ctnl_timeout *cur, *last;
 219
 220         if (cb->args[2])
 221                 return 0;
 222
 223         last = (struct ctnl_timeout *)cb->args[1];
 224         if (cb->args[1])
 225                 cb->args[1] = 0;
 226
 227         rcu_read_lock();
 228         list_for_each_entry_rcu(cur, &net->nfct_timeout_list, head) {
 229                 if (last) {
 230                         if (cur != last)
 231                                 continue;
 232
 233                         last = NULL;
 234                 }
 235                 if (ctnl_timeout_fill_info(skb, NETLINK_CB(cb->skb).portid,
 236                                            cb->nlh->nlmsg_seq,
 237                                            NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
 238                                            IPCTNL_MSG_TIMEOUT_NEW, cur) < 0) {
 239                         cb->args[1] = (unsigned long)cur;
 240                         break;
 241                 }
 242         }
 243         if (!cb->args[1])
 244                 cb->args[2] = 1;
 245         rcu_read_unlock();
 246         return skb->len;
 247 }
 248
 249 static int cttimeout_get_timeout(struct net *net, struct sock *ctnl,
 250                                  struct sk_buff *skb,
 251                                  const struct nlmsghdr *nlh,
 252                                  const struct nlattr * const cda[],
 253                                  struct netlink_ext_ack *extack)
 254 {
 255         int ret = -ENOENT;
 256         char *name;
 257         struct ctnl_timeout *cur;
 258
 259         if (nlh->nlmsg_flags & NLM_F_DUMP) {
 260                 struct netlink_dump_control c = {
 261                         .dump = ctnl_timeout_dump,
 262                 };
 263                 return netlink_dump_start(ctnl, skb, nlh, &c);
 264         }
 265
 266         if (!cda[CTA_TIMEOUT_NAME])
 267                 return -EINVAL;
 268         name = nla_data(cda[CTA_TIMEOUT_NAME]);
 269
 270         list_for_each_entry(cur, &net->nfct_timeout_list, head) {
 271                 struct sk_buff *skb2;
 272
 273                 if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
 274                         continue;
 275
 276                 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 277                 if (skb2 == NULL) {
 278                         ret = -ENOMEM;
 279                         break;
 280                 }
 281
 282                 ret = ctnl_timeout_fill_info(skb2, NETLINK_CB(skb).portid,
 283                                              nlh->nlmsg_seq,
 284                                              NFNL_MSG_TYPE(nlh->nlmsg_type),
 285                                              IPCTNL_MSG_TIMEOUT_NEW, cur);
 286                 if (ret <= 0) {
 287                         kfree_skb(skb2);
 288                         break;
 289                 }
 290                 ret = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).portid,
 291                                         MSG_DONTWAIT);
 292                 if (ret > 0)
 293                         ret = 0;
 294
 295                 /* this avoids a loop in nfnetlink. */
 296                 return ret == -EAGAIN ? -ENOBUFS : ret;
 297         }
 298         return ret;
 299 }
 300
 301 static int untimeout(struct nf_conn *ct, void *timeout)
 302 {
 303         struct nf_conn_timeout *timeout_ext = nf_ct_timeout_find(ct);
 304
 305         if (timeout_ext && (!timeout || timeout_ext->timeout == timeout))
 306                 RCU_INIT_POINTER(timeout_ext->timeout, NULL);
 307
 308         /* We are not intended to delete this conntrack. */
 309         return 0;
 310 }
 311
 312 static void ctnl_untimeout(struct net *net, struct ctnl_timeout *timeout)
 313 {
 314         nf_ct_iterate_cleanup_net(net, untimeout, timeout, 0, 0);
 315 }
 316
 317 /* try to delete object, fail if it is still in use. */
 318 static int ctnl_timeout_try_del(struct net *net, struct ctnl_timeout *timeout)
 319 {
 320         int ret = 0;
 321
 322         /* We want to avoid races with ctnl_timeout_put. So only when the
 323          * current refcnt is 1, we decrease it to 0.
 324          */
 325         if (refcount_dec_if_one(&timeout->refcnt)) {
 326                 /* We are protected by nfnl mutex. */
 327                 list_del_rcu(&timeout->head);
 328                 nf_ct_l4proto_put(timeout->l4proto);
 329                 ctnl_untimeout(net, timeout);
 330                 kfree_rcu(timeout, rcu_head);
 331         } else {
 332                 ret = -EBUSY;
 333         }
 334         return ret;
 335 }
 336
 337 static int cttimeout_del_timeout(struct net *net, struct sock *ctnl,
 338                                  struct sk_buff *skb,
 339                                  const struct nlmsghdr *nlh,
 340                                  const struct nlattr * const cda[],
 341                                  struct netlink_ext_ack *extack)
 342 {
 343         struct ctnl_timeout *cur, *tmp;
 344         int ret = -ENOENT;
 345         char *name;
 346
 347         if (!cda[CTA_TIMEOUT_NAME]) {
 348                 list_for_each_entry_safe(cur, tmp, &net->nfct_timeout_list,
 349                                          head)
 350                         ctnl_timeout_try_del(net, cur);
 351
 352                 return 0;
 353         }
 354         name = nla_data(cda[CTA_TIMEOUT_NAME]);
 355
 356         list_for_each_entry(cur, &net->nfct_timeout_list, head) {
 357                 if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
 358                         continue;
 359
 360                 ret = ctnl_timeout_try_del(net, cur);
 361                 if (ret < 0)
 362                         return ret;
 363
 364                 break;
 365         }
 366         return ret;
 367 }
 368
 369 static int cttimeout_default_set(struct net *net, struct sock *ctnl,
 370                                  struct sk_buff *skb,
 371                                  const struct nlmsghdr *nlh,
 372                                  const struct nlattr * const cda[],
 373                                  struct netlink_ext_ack *extack)
 374 {
 375         const struct nf_conntrack_l4proto *l4proto;
 376         unsigned int *timeouts;
 377         __u16 l3num;
 378         __u8 l4num;
 379         int ret;
 380
 381         if (!cda[CTA_TIMEOUT_L3PROTO] ||
 382             !cda[CTA_TIMEOUT_L4PROTO] ||
 383             !cda[CTA_TIMEOUT_DATA])
 384                 return -EINVAL;
 385
 386         l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO]));
 387         l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]);
 388         l4proto = nf_ct_l4proto_find_get(l3num, l4num);
 389
 390         /* This protocol is not supported, skip. */
 391         if (l4proto->l4proto != l4num) {
 392                 ret = -EOPNOTSUPP;
 393                 goto err;
 394         }
 395
 396         timeouts = l4proto->get_timeouts(net);
 397
 398         ret = ctnl_timeout_parse_policy(timeouts, l4proto, net,
 399                                         cda[CTA_TIMEOUT_DATA]);
 400         if (ret < 0)
 401                 goto err;
 402
 403         nf_ct_l4proto_put(l4proto);
 404         return 0;
 405 err:
 406         nf_ct_l4proto_put(l4proto);
 407         return ret;
 408 }
 409
 410 static int
 411 cttimeout_default_fill_info(struct net *net, struct sk_buff *skb, u32 portid,
 412                             u32 seq, u32 type, int event,
 413                             const struct nf_conntrack_l4proto *l4proto)
 414 {
 415         struct nlmsghdr *nlh;
 416         struct nfgenmsg *nfmsg;
 417         unsigned int flags = portid ? NLM_F_MULTI : 0;
 418
 419         event = nfnl_msg_type(NFNL_SUBSYS_CTNETLINK_TIMEOUT, event);
 420         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
 421         if (nlh == NULL)
 422                 goto nlmsg_failure;
 423
 424         nfmsg = nlmsg_data(nlh);
 425         nfmsg->nfgen_family = AF_UNSPEC;
 426         nfmsg->version = NFNETLINK_V0;
 427         nfmsg->res_id = 0;
 428
 429         if (nla_put_be16(skb, CTA_TIMEOUT_L3PROTO, htons(l4proto->l3proto)) ||
 430             nla_put_u8(skb, CTA_TIMEOUT_L4PROTO, l4proto->l4proto))
 431                 goto nla_put_failure;
 432
 433         if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) {
 434                 struct nlattr *nest_parms;
 435                 unsigned int *timeouts = l4proto->get_timeouts(net);
 436                 int ret;
 437
 438                 nest_parms = nla_nest_start(skb,
 439                                             CTA_TIMEOUT_DATA | NLA_F_NESTED);
 440                 if (!nest_parms)
 441                         goto nla_put_failure;
 442
 443                 ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, timeouts);
 444                 if (ret < 0)
 445                         goto nla_put_failure;
 446
 447                 nla_nest_end(skb, nest_parms);
 448         }
 449
 450         nlmsg_end(skb, nlh);
 451         return skb->len;
 452
 453 nlmsg_failure:
 454 nla_put_failure:
 455         nlmsg_cancel(skb, nlh);
 456         return -1;
 457 }
 458
 459 static int cttimeout_default_get(struct net *net, struct sock *ctnl,
 460                                  struct sk_buff *skb,
 461                                  const struct nlmsghdr *nlh,
 462                                  const struct nlattr * const cda[],
 463                                  struct netlink_ext_ack *extack)
 464 {
 465         const struct nf_conntrack_l4proto *l4proto;
 466         struct sk_buff *skb2;
 467         int ret, err;
 468         __u16 l3num;
 469         __u8 l4num;
 470
 471         if (!cda[CTA_TIMEOUT_L3PROTO] || !cda[CTA_TIMEOUT_L4PROTO])
 472                 return -EINVAL;
 473
 474         l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO]));
 475         l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]);
 476         l4proto = nf_ct_l4proto_find_get(l3num, l4num);
 477
 478         /* This protocol is not supported, skip. */
 479         if (l4proto->l4proto != l4num) {
 480                 err = -EOPNOTSUPP;
 481                 goto err;
 482         }
 483
 484         skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 485         if (skb2 == NULL) {
 486                 err = -ENOMEM;
 487                 goto err;
 488         }
 489
 490         ret = cttimeout_default_fill_info(net, skb2, NETLINK_CB(skb).portid,
 491                                           nlh->nlmsg_seq,
 492                                           NFNL_MSG_TYPE(nlh->nlmsg_type),
 493                                           IPCTNL_MSG_TIMEOUT_DEFAULT_SET,
 494                                           l4proto);
 495         if (ret <= 0) {
 496                 kfree_skb(skb2);
 497                 err = -ENOMEM;
 498                 goto err;
 499         }
 500         ret = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).portid, MSG_DONTWAIT);
 501         if (ret > 0)
 502                 ret = 0;
 503
 504         /* this avoids a loop in nfnetlink. */
 505         return ret == -EAGAIN ? -ENOBUFS : ret;
 506 err:
 507         nf_ct_l4proto_put(l4proto);
 508         return err;
 509 }
 510
 511 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 512 static struct ctnl_timeout *
 513 ctnl_timeout_find_get(struct net *net, const char *name)
 514 {
 515         struct ctnl_timeout *timeout, *matching = NULL;
 516
 517         list_for_each_entry_rcu(timeout, &net->nfct_timeout_list, head) {
 518                 if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
 519                         continue;
 520
 521                 if (!try_module_get(THIS_MODULE))
 522                         goto err;
 523
 524                 if (!refcount_inc_not_zero(&timeout->refcnt)) {
 525                         module_put(THIS_MODULE);
 526                         goto err;
 527                 }
 528                 matching = timeout;
 529                 break;
 530         }
 531 err:
 532         return matching;
 533 }
 534
 535 static void ctnl_timeout_put(struct ctnl_timeout *timeout)
 536 {
 537         if (refcount_dec_and_test(&timeout->refcnt))
 538                 kfree_rcu(timeout, rcu_head);
 539
 540         module_put(THIS_MODULE);
 541 }
 542 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 543
 544 static const struct nfnl_callback cttimeout_cb[IPCTNL_MSG_TIMEOUT_MAX] = {
 545         [IPCTNL_MSG_TIMEOUT_NEW]        = { .call = cttimeout_new_timeout,
 546                                             .attr_count = CTA_TIMEOUT_MAX,
 547                                             .policy = cttimeout_nla_policy },
 548         [IPCTNL_MSG_TIMEOUT_GET]        = { .call = cttimeout_get_timeout,
 549                                             .attr_count = CTA_TIMEOUT_MAX,
 550                                             .policy = cttimeout_nla_policy },
 551         [IPCTNL_MSG_TIMEOUT_DELETE]     = { .call = cttimeout_del_timeout,
 552                                             .attr_count = CTA_TIMEOUT_MAX,
 553                                             .policy = cttimeout_nla_policy },
 554         [IPCTNL_MSG_TIMEOUT_DEFAULT_SET]= { .call = cttimeout_default_set,
 555                                             .attr_count = CTA_TIMEOUT_MAX,
 556                                             .policy = cttimeout_nla_policy },
 557         [IPCTNL_MSG_TIMEOUT_DEFAULT_GET]= { .call = cttimeout_default_get,
 558                                             .attr_count = CTA_TIMEOUT_MAX,
 559                                             .policy = cttimeout_nla_policy },
 560 };
 561
 562 static const struct nfnetlink_subsystem cttimeout_subsys = {
 563         .name                           = "conntrack_timeout",
 564         .subsys_id                      = NFNL_SUBSYS_CTNETLINK_TIMEOUT,
 565         .cb_count                       = IPCTNL_MSG_TIMEOUT_MAX,
 566         .cb                             = cttimeout_cb,
 567 };
 568
 569 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_TIMEOUT);
 570
 571 static int __net_init cttimeout_net_init(struct net *net)
 572 {
 573         INIT_LIST_HEAD(&net->nfct_timeout_list);
 574
 575         return 0;
 576 }
 577
 578 static void __net_exit cttimeout_net_exit(struct net *net)
 579 {
 580         struct ctnl_timeout *cur, *tmp;
 581
 582         nf_ct_unconfirmed_destroy(net);
 583         ctnl_untimeout(net, NULL);
 584
 585         list_for_each_entry_safe(cur, tmp, &net->nfct_timeout_list, head) {
 586                 list_del_rcu(&cur->head);
 587                 nf_ct_l4proto_put(cur->l4proto);
 588
 589                 if (refcount_dec_and_test(&cur->refcnt))
 590                         kfree_rcu(cur, rcu_head);
 591         }
 592 }
 593
 594 static struct pernet_operations cttimeout_ops = {
 595         .init   = cttimeout_net_init,
 596         .exit   = cttimeout_net_exit,
 597 };
 598
 599 static int __init cttimeout_init(void)
 600 {
 601         int ret;
 602
 603         ret = register_pernet_subsys(&cttimeout_ops);
 604         if (ret < 0)
 605                 return ret;
 606
 607         ret = nfnetlink_subsys_register(&cttimeout_subsys);
 608         if (ret < 0) {
 609                 pr_err("cttimeout_init: cannot register cttimeout with "
 610                         "nfnetlink.\n");
 611                 goto err_out;
 612         }
 613 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 614         RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, ctnl_timeout_find_get);
 615         RCU_INIT_POINTER(nf_ct_timeout_put_hook, ctnl_timeout_put);
 616 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 617         return 0;
 618
 619 err_out:
 620         unregister_pernet_subsys(&cttimeout_ops);
 621         return ret;
 622 }
 623
 624 static void __exit cttimeout_exit(void)
 625 {
 626         nfnetlink_subsys_unregister(&cttimeout_subsys);
 627
 628         unregister_pernet_subsys(&cttimeout_ops);
 629 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 630         RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, NULL);
 631         RCU_INIT_POINTER(nf_ct_timeout_put_hook, NULL);
 632         synchronize_rcu();
 633 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 634 }
 635
 636 module_init(cttimeout_init);
 637 module_exit(cttimeout_exit);