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 LIST_HEAD(cttimeout_list);
  42
  43 static const struct nla_policy cttimeout_nla_policy[CTA_TIMEOUT_MAX+1] = {
  44         [CTA_TIMEOUT_NAME]      = { .type = NLA_NUL_STRING,
  45                                     .len  = CTNL_TIMEOUT_NAME_MAX - 1},
  46         [CTA_TIMEOUT_L3PROTO]   = { .type = NLA_U16 },
  47         [CTA_TIMEOUT_L4PROTO]   = { .type = NLA_U8 },
  48         [CTA_TIMEOUT_DATA]      = { .type = NLA_NESTED },
  49 };
  50
  51 static int
  52 ctnl_timeout_parse_policy(void *timeouts, struct nf_conntrack_l4proto *l4proto,
  53                           struct net *net, const struct nlattr *attr)
  54 {
  55         int ret = 0;
  56
  57         if (likely(l4proto->ctnl_timeout.nlattr_to_obj)) {
  58                 struct nlattr *tb[l4proto->ctnl_timeout.nlattr_max+1];
  59
  60                 ret = nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max,
  61                                        attr, l4proto->ctnl_timeout.nla_policy);
  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
  71 cttimeout_new_timeout(struct sock *ctnl, struct sk_buff *skb,
  72                       const struct nlmsghdr *nlh,
  73                       const struct nlattr * const cda[])
  74 {
  75         __u16 l3num;
  76         __u8 l4num;
  77         struct nf_conntrack_l4proto *l4proto;
  78         struct ctnl_timeout *timeout, *matching = NULL;
  79         struct net *net = sock_net(skb->sk);
  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, &cttimeout_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         l4proto = nf_ct_l4proto_find_get(l3num, l4num);
 105
 106         /* This protocol is not supportted, skip. */
 107         if (l4proto->l4proto != l4num) {
 108                 ret = -EOPNOTSUPP;
 109                 goto err_proto_put;
 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                                 ret = -EINVAL;
 120                                 goto err_proto_put;
 121                         }
 122
 123                         ret = ctnl_timeout_parse_policy(&matching->data,
 124                                                         l4proto, net,
 125                                                         cda[CTA_TIMEOUT_DATA]);
 126                         return ret;
 127                 }
 128                 ret = -EBUSY;
 129                 goto err_proto_put;
 130         }
 131
 132         timeout = kzalloc(sizeof(struct ctnl_timeout) +
 133                           l4proto->ctnl_timeout.obj_size, GFP_KERNEL);
 134         if (timeout == NULL) {
 135                 ret = -ENOMEM;
 136                 goto err_proto_put;
 137         }
 138
 139         ret = ctnl_timeout_parse_policy(&timeout->data, l4proto, net,
 140                                         cda[CTA_TIMEOUT_DATA]);
 141         if (ret < 0)
 142                 goto err;
 143
 144         strcpy(timeout->name, nla_data(cda[CTA_TIMEOUT_NAME]));
 145         timeout->l3num = l3num;
 146         timeout->l4proto = l4proto;
 147         atomic_set(&timeout->refcnt, 1);
 148         list_add_tail_rcu(&timeout->head, &cttimeout_list);
 149
 150         return 0;
 151 err:
 152         kfree(timeout);
 153 err_proto_put:
 154         nf_ct_l4proto_put(l4proto);
 155         return ret;
 156 }
 157
 158 static int
 159 ctnl_timeout_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
 160                        int event, struct ctnl_timeout *timeout)
 161 {
 162         struct nlmsghdr *nlh;
 163         struct nfgenmsg *nfmsg;
 164         unsigned int flags = portid ? NLM_F_MULTI : 0;
 165         struct nf_conntrack_l4proto *l4proto = timeout->l4proto;
 166
 167         event |= NFNL_SUBSYS_CTNETLINK_TIMEOUT << 8;
 168         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
 169         if (nlh == NULL)
 170                 goto nlmsg_failure;
 171
 172         nfmsg = nlmsg_data(nlh);
 173         nfmsg->nfgen_family = AF_UNSPEC;
 174         nfmsg->version = NFNETLINK_V0;
 175         nfmsg->res_id = 0;
 176
 177         if (nla_put_string(skb, CTA_TIMEOUT_NAME, timeout->name) ||
 178             nla_put_be16(skb, CTA_TIMEOUT_L3PROTO, htons(timeout->l3num)) ||
 179             nla_put_u8(skb, CTA_TIMEOUT_L4PROTO, timeout->l4proto->l4proto) ||
 180             nla_put_be32(skb, CTA_TIMEOUT_USE,
 181                          htonl(atomic_read(&timeout->refcnt))))
 182                 goto nla_put_failure;
 183
 184         if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) {
 185                 struct nlattr *nest_parms;
 186                 int ret;
 187
 188                 nest_parms = nla_nest_start(skb,
 189                                             CTA_TIMEOUT_DATA | NLA_F_NESTED);
 190                 if (!nest_parms)
 191                         goto nla_put_failure;
 192
 193                 ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, &timeout->data);
 194                 if (ret < 0)
 195                         goto nla_put_failure;
 196
 197                 nla_nest_end(skb, nest_parms);
 198         }
 199
 200         nlmsg_end(skb, nlh);
 201         return skb->len;
 202
 203 nlmsg_failure:
 204 nla_put_failure:
 205         nlmsg_cancel(skb, nlh);
 206         return -1;
 207 }
 208
 209 static int
 210 ctnl_timeout_dump(struct sk_buff *skb, struct netlink_callback *cb)
 211 {
 212         struct ctnl_timeout *cur, *last;
 213
 214         if (cb->args[2])
 215                 return 0;
 216
 217         last = (struct ctnl_timeout *)cb->args[1];
 218         if (cb->args[1])
 219                 cb->args[1] = 0;
 220
 221         rcu_read_lock();
 222         list_for_each_entry_rcu(cur, &cttimeout_list, head) {
 223                 if (last) {
 224                         if (cur != last)
 225                                 continue;
 226
 227                         last = NULL;
 228                 }
 229                 if (ctnl_timeout_fill_info(skb, NETLINK_CB(cb->skb).portid,
 230                                            cb->nlh->nlmsg_seq,
 231                                            NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
 232                                            IPCTNL_MSG_TIMEOUT_NEW, cur) < 0) {
 233                         cb->args[1] = (unsigned long)cur;
 234                         break;
 235                 }
 236         }
 237         if (!cb->args[1])
 238                 cb->args[2] = 1;
 239         rcu_read_unlock();
 240         return skb->len;
 241 }
 242
 243 static int
 244 cttimeout_get_timeout(struct sock *ctnl, struct sk_buff *skb,
 245                       const struct nlmsghdr *nlh,
 246                       const struct nlattr * const cda[])
 247 {
 248         int ret = -ENOENT;
 249         char *name;
 250         struct ctnl_timeout *cur;
 251
 252         if (nlh->nlmsg_flags & NLM_F_DUMP) {
 253                 struct netlink_dump_control c = {
 254                         .dump = ctnl_timeout_dump,
 255                 };
 256                 return netlink_dump_start(ctnl, skb, nlh, &c);
 257         }
 258
 259         if (!cda[CTA_TIMEOUT_NAME])
 260                 return -EINVAL;
 261         name = nla_data(cda[CTA_TIMEOUT_NAME]);
 262
 263         list_for_each_entry(cur, &cttimeout_list, head) {
 264                 struct sk_buff *skb2;
 265
 266                 if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
 267                         continue;
 268
 269                 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 270                 if (skb2 == NULL) {
 271                         ret = -ENOMEM;
 272                         break;
 273                 }
 274
 275                 ret = ctnl_timeout_fill_info(skb2, NETLINK_CB(skb).portid,
 276                                              nlh->nlmsg_seq,
 277                                              NFNL_MSG_TYPE(nlh->nlmsg_type),
 278                                              IPCTNL_MSG_TIMEOUT_NEW, cur);
 279                 if (ret <= 0) {
 280                         kfree_skb(skb2);
 281                         break;
 282                 }
 283                 ret = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).portid,
 284                                         MSG_DONTWAIT);
 285                 if (ret > 0)
 286                         ret = 0;
 287
 288                 /* this avoids a loop in nfnetlink. */
 289                 return ret == -EAGAIN ? -ENOBUFS : ret;
 290         }
 291         return ret;
 292 }
 293
 294 static void untimeout(struct nf_conntrack_tuple_hash *i,
 295                       struct ctnl_timeout *timeout)
 296 {
 297         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(i);
 298         struct nf_conn_timeout *timeout_ext = nf_ct_timeout_find(ct);
 299
 300         if (timeout_ext && (!timeout || timeout_ext->timeout == timeout))
 301                 RCU_INIT_POINTER(timeout_ext->timeout, NULL);
 302 }
 303
 304 static void ctnl_untimeout(struct ctnl_timeout *timeout)
 305 {
 306         struct nf_conntrack_tuple_hash *h;
 307         const struct hlist_nulls_node *nn;
 308         int i;
 309
 310         local_bh_disable();
 311         for (i = 0; i < init_net.ct.htable_size; i++) {
 312                 spin_lock(&nf_conntrack_locks[i % CONNTRACK_LOCKS]);
 313                 if (i < init_net.ct.htable_size) {
 314                         hlist_nulls_for_each_entry(h, nn, &init_net.ct.hash[i], hnnode)
 315                                 untimeout(h, timeout);
 316                 }
 317                 spin_unlock(&nf_conntrack_locks[i % CONNTRACK_LOCKS]);
 318         }
 319         local_bh_enable();
 320 }
 321
 322 /* try to delete object, fail if it is still in use. */
 323 static int ctnl_timeout_try_del(struct ctnl_timeout *timeout)
 324 {
 325         int ret = 0;
 326
 327         /* we want to avoid races with nf_ct_timeout_find_get. */
 328         if (atomic_dec_and_test(&timeout->refcnt)) {
 329                 /* We are protected by nfnl mutex. */
 330                 list_del_rcu(&timeout->head);
 331                 nf_ct_l4proto_put(timeout->l4proto);
 332                 ctnl_untimeout(timeout);
 333                 kfree_rcu(timeout, rcu_head);
 334         } else {
 335                 /* still in use, restore reference counter. */
 336                 atomic_inc(&timeout->refcnt);
 337                 ret = -EBUSY;
 338         }
 339         return ret;
 340 }
 341
 342 static int
 343 cttimeout_del_timeout(struct sock *ctnl, struct sk_buff *skb,
 344                       const struct nlmsghdr *nlh,
 345                       const struct nlattr * const cda[])
 346 {
 347         char *name;
 348         struct ctnl_timeout *cur;
 349         int ret = -ENOENT;
 350
 351         if (!cda[CTA_TIMEOUT_NAME]) {
 352                 list_for_each_entry(cur, &cttimeout_list, head)
 353                         ctnl_timeout_try_del(cur);
 354
 355                 return 0;
 356         }
 357         name = nla_data(cda[CTA_TIMEOUT_NAME]);
 358
 359         list_for_each_entry(cur, &cttimeout_list, head) {
 360                 if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
 361                         continue;
 362
 363                 ret = ctnl_timeout_try_del(cur);
 364                 if (ret < 0)
 365                         return ret;
 366
 367                 break;
 368         }
 369         return ret;
 370 }
 371
 372 static int
 373 cttimeout_default_set(struct sock *ctnl, struct sk_buff *skb,
 374                       const struct nlmsghdr *nlh,
 375                       const struct nlattr * const cda[])
 376 {
 377         __u16 l3num;
 378         __u8 l4num;
 379         struct nf_conntrack_l4proto *l4proto;
 380         struct net *net = sock_net(skb->sk);
 381         unsigned int *timeouts;
 382         int ret;
 383
 384         if (!cda[CTA_TIMEOUT_L3PROTO] ||
 385             !cda[CTA_TIMEOUT_L4PROTO] ||
 386             !cda[CTA_TIMEOUT_DATA])
 387                 return -EINVAL;
 388
 389         l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO]));
 390         l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]);
 391         l4proto = nf_ct_l4proto_find_get(l3num, l4num);
 392
 393         /* This protocol is not supported, skip. */
 394         if (l4proto->l4proto != l4num) {
 395                 ret = -EOPNOTSUPP;
 396                 goto err;
 397         }
 398
 399         timeouts = l4proto->get_timeouts(net);
 400
 401         ret = ctnl_timeout_parse_policy(timeouts, l4proto, net,
 402                                         cda[CTA_TIMEOUT_DATA]);
 403         if (ret < 0)
 404                 goto err;
 405
 406         nf_ct_l4proto_put(l4proto);
 407         return 0;
 408 err:
 409         nf_ct_l4proto_put(l4proto);
 410         return ret;
 411 }
 412
 413 static int
 414 cttimeout_default_fill_info(struct net *net, struct sk_buff *skb, u32 portid,
 415                             u32 seq, u32 type, int event,
 416                             struct nf_conntrack_l4proto *l4proto)
 417 {
 418         struct nlmsghdr *nlh;
 419         struct nfgenmsg *nfmsg;
 420         unsigned int flags = portid ? NLM_F_MULTI : 0;
 421
 422         event |= NFNL_SUBSYS_CTNETLINK_TIMEOUT << 8;
 423         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
 424         if (nlh == NULL)
 425                 goto nlmsg_failure;
 426
 427         nfmsg = nlmsg_data(nlh);
 428         nfmsg->nfgen_family = AF_UNSPEC;
 429         nfmsg->version = NFNETLINK_V0;
 430         nfmsg->res_id = 0;
 431
 432         if (nla_put_be16(skb, CTA_TIMEOUT_L3PROTO, htons(l4proto->l3proto)) ||
 433             nla_put_u8(skb, CTA_TIMEOUT_L4PROTO, l4proto->l4proto))
 434                 goto nla_put_failure;
 435
 436         if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) {
 437                 struct nlattr *nest_parms;
 438                 unsigned int *timeouts = l4proto->get_timeouts(net);
 439                 int ret;
 440
 441                 nest_parms = nla_nest_start(skb,
 442                                             CTA_TIMEOUT_DATA | NLA_F_NESTED);
 443                 if (!nest_parms)
 444                         goto nla_put_failure;
 445
 446                 ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, timeouts);
 447                 if (ret < 0)
 448                         goto nla_put_failure;
 449
 450                 nla_nest_end(skb, nest_parms);
 451         }
 452
 453         nlmsg_end(skb, nlh);
 454         return skb->len;
 455
 456 nlmsg_failure:
 457 nla_put_failure:
 458         nlmsg_cancel(skb, nlh);
 459         return -1;
 460 }
 461
 462 static int cttimeout_default_get(struct sock *ctnl, struct sk_buff *skb,
 463                                  const struct nlmsghdr *nlh,
 464                                  const struct nlattr * const cda[])
 465 {
 466         __u16 l3num;
 467         __u8 l4num;
 468         struct nf_conntrack_l4proto *l4proto;
 469         struct net *net = sock_net(skb->sk);
 470         struct sk_buff *skb2;
 471         int ret, err;
 472
 473         if (!cda[CTA_TIMEOUT_L3PROTO] || !cda[CTA_TIMEOUT_L4PROTO])
 474                 return -EINVAL;
 475
 476         l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO]));
 477         l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]);
 478         l4proto = nf_ct_l4proto_find_get(l3num, l4num);
 479
 480         /* This protocol is not supported, skip. */
 481         if (l4proto->l4proto != l4num) {
 482                 err = -EOPNOTSUPP;
 483                 goto err;
 484         }
 485
 486         skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 487         if (skb2 == NULL) {
 488                 err = -ENOMEM;
 489                 goto err;
 490         }
 491
 492         ret = cttimeout_default_fill_info(net, skb2, NETLINK_CB(skb).portid,
 493                                           nlh->nlmsg_seq,
 494                                           NFNL_MSG_TYPE(nlh->nlmsg_type),
 495                                           IPCTNL_MSG_TIMEOUT_DEFAULT_SET,
 496                                           l4proto);
 497         if (ret <= 0) {
 498                 kfree_skb(skb2);
 499                 err = -ENOMEM;
 500                 goto err;
 501         }
 502         ret = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).portid, MSG_DONTWAIT);
 503         if (ret > 0)
 504                 ret = 0;
 505
 506         /* this avoids a loop in nfnetlink. */
 507         return ret == -EAGAIN ? -ENOBUFS : ret;
 508 err:
 509         nf_ct_l4proto_put(l4proto);
 510         return err;
 511 }
 512
 513 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 514 static struct ctnl_timeout *ctnl_timeout_find_get(const char *name)
 515 {
 516         struct ctnl_timeout *timeout, *matching = NULL;
 517
 518         rcu_read_lock();
 519         list_for_each_entry_rcu(timeout, &cttimeout_list, head) {
 520                 if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
 521                         continue;
 522
 523                 if (!try_module_get(THIS_MODULE))
 524                         goto err;
 525
 526                 if (!atomic_inc_not_zero(&timeout->refcnt)) {
 527                         module_put(THIS_MODULE);
 528                         goto err;
 529                 }
 530                 matching = timeout;
 531                 break;
 532         }
 533 err:
 534         rcu_read_unlock();
 535         return matching;
 536 }
 537
 538 static void ctnl_timeout_put(struct ctnl_timeout *timeout)
 539 {
 540         atomic_dec(&timeout->refcnt);
 541         module_put(THIS_MODULE);
 542 }
 543 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 544
 545 static const struct nfnl_callback cttimeout_cb[IPCTNL_MSG_TIMEOUT_MAX] = {
 546         [IPCTNL_MSG_TIMEOUT_NEW]        = { .call = cttimeout_new_timeout,
 547                                             .attr_count = CTA_TIMEOUT_MAX,
 548                                             .policy = cttimeout_nla_policy },
 549         [IPCTNL_MSG_TIMEOUT_GET]        = { .call = cttimeout_get_timeout,
 550                                             .attr_count = CTA_TIMEOUT_MAX,
 551                                             .policy = cttimeout_nla_policy },
 552         [IPCTNL_MSG_TIMEOUT_DELETE]     = { .call = cttimeout_del_timeout,
 553                                             .attr_count = CTA_TIMEOUT_MAX,
 554                                             .policy = cttimeout_nla_policy },
 555         [IPCTNL_MSG_TIMEOUT_DEFAULT_SET]= { .call = cttimeout_default_set,
 556                                             .attr_count = CTA_TIMEOUT_MAX,
 557                                             .policy = cttimeout_nla_policy },
 558         [IPCTNL_MSG_TIMEOUT_DEFAULT_GET]= { .call = cttimeout_default_get,
 559                                             .attr_count = CTA_TIMEOUT_MAX,
 560                                             .policy = cttimeout_nla_policy },
 561 };
 562
 563 static const struct nfnetlink_subsystem cttimeout_subsys = {
 564         .name                           = "conntrack_timeout",
 565         .subsys_id                      = NFNL_SUBSYS_CTNETLINK_TIMEOUT,
 566         .cb_count                       = IPCTNL_MSG_TIMEOUT_MAX,
 567         .cb                             = cttimeout_cb,
 568 };
 569
 570 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_TIMEOUT);
 571
 572 static int __init cttimeout_init(void)
 573 {
 574         int ret;
 575
 576         ret = nfnetlink_subsys_register(&cttimeout_subsys);
 577         if (ret < 0) {
 578                 pr_err("cttimeout_init: cannot register cttimeout with "
 579                         "nfnetlink.\n");
 580                 goto err_out;
 581         }
 582 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 583         RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, ctnl_timeout_find_get);
 584         RCU_INIT_POINTER(nf_ct_timeout_put_hook, ctnl_timeout_put);
 585 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 586         return 0;
 587
 588 err_out:
 589         return ret;
 590 }
 591
 592 static void __exit cttimeout_exit(void)
 593 {
 594         struct ctnl_timeout *cur, *tmp;
 595
 596         pr_info("cttimeout: unregistering from nfnetlink.\n");
 597
 598         nfnetlink_subsys_unregister(&cttimeout_subsys);
 599
 600         /* Make sure no conntrack objects refer to custom timeouts anymore. */
 601         ctnl_untimeout(NULL);
 602
 603         list_for_each_entry_safe(cur, tmp, &cttimeout_list, head) {
 604                 list_del_rcu(&cur->head);
 605                 /* We are sure that our objects have no clients at this point,
 606                  * it's safe to release them all without checking refcnt.
 607                  */
 608                 nf_ct_l4proto_put(cur->l4proto);
 609                 kfree_rcu(cur, rcu_head);
 610         }
 611 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 612         RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, NULL);
 613         RCU_INIT_POINTER(nf_ct_timeout_put_hook, NULL);
 614 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 615         rcu_barrier();
 616 }
 617
 618 module_init(cttimeout_init);
 619 module_exit(cttimeout_exit);