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, struct nf_conntrack_l4proto *l4proto,
  51                           struct net *net, const struct nlattr *attr)
  52 {
  53         int ret = 0;
  54
  55         if (likely(l4proto->ctnl_timeout.nlattr_to_obj)) {
  56                 struct nlattr *tb[l4proto->ctnl_timeout.nlattr_max+1];
  57
  58                 ret = nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max,
  59                                        attr, l4proto->ctnl_timeout.nla_policy);
  60                 if (ret < 0)
  61                         return ret;
  62
  63                 ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, net, timeouts);
  64         }
  65         return ret;
  66 }
  67
  68 static int cttimeout_new_timeout(struct net *net, struct sock *ctnl,
  69                                  struct sk_buff *skb,
  70                                  const struct nlmsghdr *nlh,
  71                                  const struct nlattr * const cda[])
  72 {
  73         __u16 l3num;
  74         __u8 l4num;
  75         struct nf_conntrack_l4proto *l4proto;
  76         struct ctnl_timeout *timeout, *matching = NULL;
  77         char *name;
  78         int ret;
  79
  80         if (!cda[CTA_TIMEOUT_NAME] ||
  81             !cda[CTA_TIMEOUT_L3PROTO] ||
  82             !cda[CTA_TIMEOUT_L4PROTO] ||
  83             !cda[CTA_TIMEOUT_DATA])
  84                 return -EINVAL;
  85
  86         name = nla_data(cda[CTA_TIMEOUT_NAME]);
  87         l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO]));
  88         l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]);
  89
  90         list_for_each_entry(timeout, &net->nfct_timeout_list, head) {
  91                 if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
  92                         continue;
  93
  94                 if (nlh->nlmsg_flags & NLM_F_EXCL)
  95                         return -EEXIST;
  96
  97                 matching = timeout;
  98                 break;
  99         }
 100
 101         l4proto = nf_ct_l4proto_find_get(l3num, l4num);
 102
 103         /* This protocol is not supportted, skip. */
 104         if (l4proto->l4proto != l4num) {
 105                 ret = -EOPNOTSUPP;
 106                 goto err_proto_put;
 107         }
 108
 109         if (matching) {
 110                 if (nlh->nlmsg_flags & NLM_F_REPLACE) {
 111                         /* You cannot replace one timeout policy by another of
 112                          * different kind, sorry.
 113                          */
 114                         if (matching->l3num != l3num ||
 115                             matching->l4proto->l4proto != l4num) {
 116                                 ret = -EINVAL;
 117                                 goto err_proto_put;
 118                         }
 119
 120                         ret = ctnl_timeout_parse_policy(&matching->data,
 121                                                         l4proto, net,
 122                                                         cda[CTA_TIMEOUT_DATA]);
 123                         return ret;
 124                 }
 125                 ret = -EBUSY;
 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         atomic_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         struct nf_conntrack_l4proto *l4proto = timeout->l4proto;
 163
 164         event |= NFNL_SUBSYS_CTNETLINK_TIMEOUT << 8;
 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(atomic_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 {
 246         int ret = -ENOENT;
 247         char *name;
 248         struct ctnl_timeout *cur;
 249
 250         if (nlh->nlmsg_flags & NLM_F_DUMP) {
 251                 struct netlink_dump_control c = {
 252                         .dump = ctnl_timeout_dump,
 253                 };
 254                 return netlink_dump_start(ctnl, skb, nlh, &c);
 255         }
 256
 257         if (!cda[CTA_TIMEOUT_NAME])
 258                 return -EINVAL;
 259         name = nla_data(cda[CTA_TIMEOUT_NAME]);
 260
 261         list_for_each_entry(cur, &net->nfct_timeout_list, head) {
 262                 struct sk_buff *skb2;
 263
 264                 if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
 265                         continue;
 266
 267                 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 268                 if (skb2 == NULL) {
 269                         ret = -ENOMEM;
 270                         break;
 271                 }
 272
 273                 ret = ctnl_timeout_fill_info(skb2, NETLINK_CB(skb).portid,
 274                                              nlh->nlmsg_seq,
 275                                              NFNL_MSG_TYPE(nlh->nlmsg_type),
 276                                              IPCTNL_MSG_TIMEOUT_NEW, cur);
 277                 if (ret <= 0) {
 278                         kfree_skb(skb2);
 279                         break;
 280                 }
 281                 ret = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).portid,
 282                                         MSG_DONTWAIT);
 283                 if (ret > 0)
 284                         ret = 0;
 285
 286                 /* this avoids a loop in nfnetlink. */
 287                 return ret == -EAGAIN ? -ENOBUFS : ret;
 288         }
 289         return ret;
 290 }
 291
 292 static void untimeout(struct nf_conntrack_tuple_hash *i,
 293                       struct ctnl_timeout *timeout)
 294 {
 295         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(i);
 296         struct nf_conn_timeout *timeout_ext = nf_ct_timeout_find(ct);
 297
 298         if (timeout_ext && (!timeout || timeout_ext->timeout == timeout))
 299                 RCU_INIT_POINTER(timeout_ext->timeout, NULL);
 300 }
 301
 302 static void ctnl_untimeout(struct net *net, struct ctnl_timeout *timeout)
 303 {
 304         struct nf_conntrack_tuple_hash *h;
 305         const struct hlist_nulls_node *nn;
 306         int i;
 307
 308         local_bh_disable();
 309         for (i = 0; i < net->ct.htable_size; i++) {
 310                 nf_conntrack_lock(&nf_conntrack_locks[i % CONNTRACK_LOCKS]);
 311                 if (i < net->ct.htable_size) {
 312                         hlist_nulls_for_each_entry(h, nn, &net->ct.hash[i], hnnode)
 313                                 untimeout(h, timeout);
 314                 }
 315                 spin_unlock(&nf_conntrack_locks[i % CONNTRACK_LOCKS]);
 316         }
 317         local_bh_enable();
 318 }
 319
 320 /* try to delete object, fail if it is still in use. */
 321 static int ctnl_timeout_try_del(struct net *net, struct ctnl_timeout *timeout)
 322 {
 323         int ret = 0;
 324
 325         /* we want to avoid races with nf_ct_timeout_find_get. */
 326         if (atomic_dec_and_test(&timeout->refcnt)) {
 327                 /* We are protected by nfnl mutex. */
 328                 list_del_rcu(&timeout->head);
 329                 nf_ct_l4proto_put(timeout->l4proto);
 330                 ctnl_untimeout(net, timeout);
 331                 kfree_rcu(timeout, rcu_head);
 332         } else {
 333                 /* still in use, restore reference counter. */
 334                 atomic_inc(&timeout->refcnt);
 335                 ret = -EBUSY;
 336         }
 337         return ret;
 338 }
 339
 340 static int cttimeout_del_timeout(struct net *net, struct sock *ctnl,
 341                                  struct sk_buff *skb,
 342                                  const struct nlmsghdr *nlh,
 343                                  const struct nlattr * const cda[])
 344 {
 345         struct ctnl_timeout *cur;
 346         int ret = -ENOENT;
 347         char *name;
 348
 349         if (!cda[CTA_TIMEOUT_NAME]) {
 350                 list_for_each_entry(cur, &net->nfct_timeout_list, head)
 351                         ctnl_timeout_try_del(net, cur);
 352
 353                 return 0;
 354         }
 355         name = nla_data(cda[CTA_TIMEOUT_NAME]);
 356
 357         list_for_each_entry(cur, &net->nfct_timeout_list, head) {
 358                 if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
 359                         continue;
 360
 361                 ret = ctnl_timeout_try_del(net, cur);
 362                 if (ret < 0)
 363                         return ret;
 364
 365                 break;
 366         }
 367         return ret;
 368 }
 369
 370 static int cttimeout_default_set(struct net *net, struct sock *ctnl,
 371                                  struct sk_buff *skb,
 372                                  const struct nlmsghdr *nlh,
 373                                  const struct nlattr * const cda[])
 374 {
 375         __u16 l3num;
 376         __u8 l4num;
 377         struct nf_conntrack_l4proto *l4proto;
 378         unsigned int *timeouts;
 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                             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_SUBSYS_CTNETLINK_TIMEOUT << 8;
 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 {
 464         __u16 l3num;
 465         __u8 l4num;
 466         struct nf_conntrack_l4proto *l4proto;
 467         struct sk_buff *skb2;
 468         int ret, err;
 469
 470         if (!cda[CTA_TIMEOUT_L3PROTO] || !cda[CTA_TIMEOUT_L4PROTO])
 471                 return -EINVAL;
 472
 473         l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO]));
 474         l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]);
 475         l4proto = nf_ct_l4proto_find_get(l3num, l4num);
 476
 477         /* This protocol is not supported, skip. */
 478         if (l4proto->l4proto != l4num) {
 479                 err = -EOPNOTSUPP;
 480                 goto err;
 481         }
 482
 483         skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 484         if (skb2 == NULL) {
 485                 err = -ENOMEM;
 486                 goto err;
 487         }
 488
 489         ret = cttimeout_default_fill_info(net, skb2, NETLINK_CB(skb).portid,
 490                                           nlh->nlmsg_seq,
 491                                           NFNL_MSG_TYPE(nlh->nlmsg_type),
 492                                           IPCTNL_MSG_TIMEOUT_DEFAULT_SET,
 493                                           l4proto);
 494         if (ret <= 0) {
 495                 kfree_skb(skb2);
 496                 err = -ENOMEM;
 497                 goto err;
 498         }
 499         ret = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).portid, MSG_DONTWAIT);
 500         if (ret > 0)
 501                 ret = 0;
 502
 503         /* this avoids a loop in nfnetlink. */
 504         return ret == -EAGAIN ? -ENOBUFS : ret;
 505 err:
 506         nf_ct_l4proto_put(l4proto);
 507         return err;
 508 }
 509
 510 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 511 static struct ctnl_timeout *
 512 ctnl_timeout_find_get(struct net *net, const char *name)
 513 {
 514         struct ctnl_timeout *timeout, *matching = NULL;
 515
 516         rcu_read_lock();
 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 (!atomic_inc_not_zero(&timeout->refcnt)) {
 525                         module_put(THIS_MODULE);
 526                         goto err;
 527                 }
 528                 matching = timeout;
 529                 break;
 530         }
 531 err:
 532         rcu_read_unlock();
 533         return matching;
 534 }
 535
 536 static void ctnl_timeout_put(struct ctnl_timeout *timeout)
 537 {
 538         atomic_dec(&timeout->refcnt);
 539         module_put(THIS_MODULE);
 540 }
 541 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 542
 543 static const struct nfnl_callback cttimeout_cb[IPCTNL_MSG_TIMEOUT_MAX] = {
 544         [IPCTNL_MSG_TIMEOUT_NEW]        = { .call = cttimeout_new_timeout,
 545                                             .attr_count = CTA_TIMEOUT_MAX,
 546                                             .policy = cttimeout_nla_policy },
 547         [IPCTNL_MSG_TIMEOUT_GET]        = { .call = cttimeout_get_timeout,
 548                                             .attr_count = CTA_TIMEOUT_MAX,
 549                                             .policy = cttimeout_nla_policy },
 550         [IPCTNL_MSG_TIMEOUT_DELETE]     = { .call = cttimeout_del_timeout,
 551                                             .attr_count = CTA_TIMEOUT_MAX,
 552                                             .policy = cttimeout_nla_policy },
 553         [IPCTNL_MSG_TIMEOUT_DEFAULT_SET]= { .call = cttimeout_default_set,
 554                                             .attr_count = CTA_TIMEOUT_MAX,
 555                                             .policy = cttimeout_nla_policy },
 556         [IPCTNL_MSG_TIMEOUT_DEFAULT_GET]= { .call = cttimeout_default_get,
 557                                             .attr_count = CTA_TIMEOUT_MAX,
 558                                             .policy = cttimeout_nla_policy },
 559 };
 560
 561 static const struct nfnetlink_subsystem cttimeout_subsys = {
 562         .name                           = "conntrack_timeout",
 563         .subsys_id                      = NFNL_SUBSYS_CTNETLINK_TIMEOUT,
 564         .cb_count                       = IPCTNL_MSG_TIMEOUT_MAX,
 565         .cb                             = cttimeout_cb,
 566 };
 567
 568 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_TIMEOUT);
 569
 570 static int __net_init cttimeout_net_init(struct net *net)
 571 {
 572         INIT_LIST_HEAD(&net->nfct_timeout_list);
 573
 574         return 0;
 575 }
 576
 577 static void __net_exit cttimeout_net_exit(struct net *net)
 578 {
 579         struct ctnl_timeout *cur, *tmp;
 580
 581         ctnl_untimeout(net, NULL);
 582
 583         list_for_each_entry_safe(cur, tmp, &net->nfct_timeout_list, head) {
 584                 list_del_rcu(&cur->head);
 585                 nf_ct_l4proto_put(cur->l4proto);
 586                 kfree_rcu(cur, rcu_head);
 587         }
 588 }
 589
 590 static struct pernet_operations cttimeout_ops = {
 591         .init   = cttimeout_net_init,
 592         .exit   = cttimeout_net_exit,
 593 };
 594
 595 static int __init cttimeout_init(void)
 596 {
 597         int ret;
 598
 599         ret = register_pernet_subsys(&cttimeout_ops);
 600         if (ret < 0)
 601                 return ret;
 602
 603         ret = nfnetlink_subsys_register(&cttimeout_subsys);
 604         if (ret < 0) {
 605                 pr_err("cttimeout_init: cannot register cttimeout with "
 606                         "nfnetlink.\n");
 607                 goto err_out;
 608         }
 609 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 610         RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, ctnl_timeout_find_get);
 611         RCU_INIT_POINTER(nf_ct_timeout_put_hook, ctnl_timeout_put);
 612 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 613         return 0;
 614
 615 err_out:
 616         unregister_pernet_subsys(&cttimeout_ops);
 617         return ret;
 618 }
 619
 620 static void __exit cttimeout_exit(void)
 621 {
 622         pr_info("cttimeout: unregistering from nfnetlink.\n");
 623
 624         nfnetlink_subsys_unregister(&cttimeout_subsys);
 625
 626         unregister_pernet_subsys(&cttimeout_ops);
 627 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 628         RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, NULL);
 629         RCU_INIT_POINTER(nf_ct_timeout_put_hook, NULL);
 630 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 631         rcu_barrier();
 632 }
 633
 634 module_init(cttimeout_init);
 635 module_exit(cttimeout_exit);