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