net/netfilter/nfnetlink.c

   1 /* Netfilter messages via netlink socket. Allows for user space
   2  * protocol helpers and general trouble making from userspace.
   3  *
   4  * (C) 2001 by Jay Schulist <jschlst@samba.org>,
   5  * (C) 2002-2005 by Harald Welte <laforge@gnumonks.org>
   6  * (C) 2005-2017 by Pablo Neira Ayuso <pablo@netfilter.org>
   7  *
   8  * Initial netfilter messages via netlink development funded and
   9  * generally made possible by Network Robots, Inc. (www.networkrobots.com)
  10  *
  11  * Further development of this code funded by Astaro AG (http://www.astaro.com)
  12  *
  13  * This software may be used and distributed according to the terms
  14  * of the GNU General Public License, incorporated herein by reference.
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/types.h>
  19 #include <linux/socket.h>
  20 #include <linux/kernel.h>
  21 #include <linux/string.h>
  22 #include <linux/sockios.h>
  23 #include <linux/net.h>
  24 #include <linux/skbuff.h>
  25 #include <linux/uaccess.h>
  26 #include <net/sock.h>
  27 #include <linux/init.h>
  28 #include <linux/sched/signal.h>
  29
  30 #include <net/netlink.h>
  31 #include <linux/netfilter/nfnetlink.h>
  32
  33 MODULE_LICENSE("GPL");
  34 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
  35 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
  36
  37 #define nfnl_dereference_protected(id) \
  38         rcu_dereference_protected(table[(id)].subsys, \
  39                                   lockdep_nfnl_is_held((id)))
  40
  41 #define NFNL_MAX_ATTR_COUNT     32
  42
  43 static struct {
  44         struct mutex                            mutex;
  45         const struct nfnetlink_subsystem __rcu  *subsys;
  46 } table[NFNL_SUBSYS_COUNT];
  47
  48 static const int nfnl_group2type[NFNLGRP_MAX+1] = {
  49         [NFNLGRP_CONNTRACK_NEW]         = NFNL_SUBSYS_CTNETLINK,
  50         [NFNLGRP_CONNTRACK_UPDATE]      = NFNL_SUBSYS_CTNETLINK,
  51         [NFNLGRP_CONNTRACK_DESTROY]     = NFNL_SUBSYS_CTNETLINK,
  52         [NFNLGRP_CONNTRACK_EXP_NEW]     = NFNL_SUBSYS_CTNETLINK_EXP,
  53         [NFNLGRP_CONNTRACK_EXP_UPDATE]  = NFNL_SUBSYS_CTNETLINK_EXP,
  54         [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP,
  55         [NFNLGRP_NFTABLES]              = NFNL_SUBSYS_NFTABLES,
  56         [NFNLGRP_ACCT_QUOTA]            = NFNL_SUBSYS_ACCT,
  57         [NFNLGRP_NFTRACE]               = NFNL_SUBSYS_NFTABLES,
  58 };
  59
  60 void nfnl_lock(__u8 subsys_id)
  61 {
  62         mutex_lock(&table[subsys_id].mutex);
  63 }
  64 EXPORT_SYMBOL_GPL(nfnl_lock);
  65
  66 void nfnl_unlock(__u8 subsys_id)
  67 {
  68         mutex_unlock(&table[subsys_id].mutex);
  69 }
  70 EXPORT_SYMBOL_GPL(nfnl_unlock);
  71
  72 #ifdef CONFIG_PROVE_LOCKING
  73 bool lockdep_nfnl_is_held(u8 subsys_id)
  74 {
  75         return lockdep_is_held(&table[subsys_id].mutex);
  76 }
  77 EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held);
  78 #endif
  79
  80 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
  81 {
  82         u8 cb_id;
  83
  84         /* Sanity-check attr_count size to avoid stack buffer overflow. */
  85         for (cb_id = 0; cb_id < n->cb_count; cb_id++)
  86                 if (WARN_ON(n->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT))
  87                         return -EINVAL;
  88
  89         nfnl_lock(n->subsys_id);
  90         if (table[n->subsys_id].subsys) {
  91                 nfnl_unlock(n->subsys_id);
  92                 return -EBUSY;
  93         }
  94         rcu_assign_pointer(table[n->subsys_id].subsys, n);
  95         nfnl_unlock(n->subsys_id);
  96
  97         return 0;
  98 }
  99 EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
 100
 101 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
 102 {
 103         nfnl_lock(n->subsys_id);
 104         table[n->subsys_id].subsys = NULL;
 105         nfnl_unlock(n->subsys_id);
 106         synchronize_rcu();
 107         return 0;
 108 }
 109 EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
 110
 111 static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u16 type)
 112 {
 113         u8 subsys_id = NFNL_SUBSYS_ID(type);
 114
 115         if (subsys_id >= NFNL_SUBSYS_COUNT)
 116                 return NULL;
 117
 118         return rcu_dereference(table[subsys_id].subsys);
 119 }
 120
 121 static inline const struct nfnl_callback *
 122 nfnetlink_find_client(u16 type, const struct nfnetlink_subsystem *ss)
 123 {
 124         u8 cb_id = NFNL_MSG_TYPE(type);
 125
 126         if (cb_id >= ss->cb_count)
 127                 return NULL;
 128
 129         return &ss->cb[cb_id];
 130 }
 131
 132 int nfnetlink_has_listeners(struct net *net, unsigned int group)
 133 {
 134         return netlink_has_listeners(net->nfnl, group);
 135 }
 136 EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
 137
 138 int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid,
 139                    unsigned int group, int echo, gfp_t flags)
 140 {
 141         return nlmsg_notify(net->nfnl, skb, portid, group, echo, flags);
 142 }
 143 EXPORT_SYMBOL_GPL(nfnetlink_send);
 144
 145 int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error)
 146 {
 147         return netlink_set_err(net->nfnl, portid, group, error);
 148 }
 149 EXPORT_SYMBOL_GPL(nfnetlink_set_err);
 150
 151 int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid,
 152                       int flags)
 153 {
 154         return netlink_unicast(net->nfnl, skb, portid, flags);
 155 }
 156 EXPORT_SYMBOL_GPL(nfnetlink_unicast);
 157
 158 /* Process one complete nfnetlink message. */
 159 static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 160                              struct netlink_ext_ack *extack)
 161 {
 162         struct net *net = sock_net(skb->sk);
 163         const struct nfnl_callback *nc;
 164         const struct nfnetlink_subsystem *ss;
 165         int type, err;
 166
 167         /* All the messages must at least contain nfgenmsg */
 168         if (nlmsg_len(nlh) < sizeof(struct nfgenmsg))
 169                 return 0;
 170
 171         type = nlh->nlmsg_type;
 172 replay:
 173         rcu_read_lock();
 174         ss = nfnetlink_get_subsys(type);
 175         if (!ss) {
 176 #ifdef CONFIG_MODULES
 177                 rcu_read_unlock();
 178                 request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
 179                 rcu_read_lock();
 180                 ss = nfnetlink_get_subsys(type);
 181                 if (!ss)
 182 #endif
 183                 {
 184                         rcu_read_unlock();
 185                         return -EINVAL;
 186                 }
 187         }
 188
 189         nc = nfnetlink_find_client(type, ss);
 190         if (!nc) {
 191                 rcu_read_unlock();
 192                 return -EINVAL;
 193         }
 194
 195         {
 196                 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
 197                 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
 198                 struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
 199                 struct nlattr *attr = (void *)nlh + min_len;
 200                 int attrlen = nlh->nlmsg_len - min_len;
 201                 __u8 subsys_id = NFNL_SUBSYS_ID(type);
 202
 203                 /* Sanity-check NFNL_MAX_ATTR_COUNT */
 204                 if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
 205                         rcu_read_unlock();
 206                         return -ENOMEM;
 207                 }
 208
 209                 err = nla_parse(cda, ss->cb[cb_id].attr_count, attr, attrlen,
 210                                 ss->cb[cb_id].policy, extack);
 211                 if (err < 0) {
 212                         rcu_read_unlock();
 213                         return err;
 214                 }
 215
 216                 if (nc->call_rcu) {
 217                         err = nc->call_rcu(net, net->nfnl, skb, nlh,
 218                                            (const struct nlattr **)cda,
 219                                            extack);
 220                         rcu_read_unlock();
 221                 } else {
 222                         rcu_read_unlock();
 223                         nfnl_lock(subsys_id);
 224                         if (nfnl_dereference_protected(subsys_id) != ss ||
 225                             nfnetlink_find_client(type, ss) != nc)
 226                                 err = -EAGAIN;
 227                         else if (nc->call)
 228                                 err = nc->call(net, net->nfnl, skb, nlh,
 229                                                (const struct nlattr **)cda,
 230                                                extack);
 231                         else
 232                                 err = -EINVAL;
 233                         nfnl_unlock(subsys_id);
 234                 }
 235                 if (err == -EAGAIN)
 236                         goto replay;
 237                 return err;
 238         }
 239 }
 240
 241 struct nfnl_err {
 242         struct list_head        head;
 243         struct nlmsghdr         *nlh;
 244         int                     err;
 245         struct netlink_ext_ack  extack;
 246 };
 247
 248 static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err,
 249                         const struct netlink_ext_ack *extack)
 250 {
 251         struct nfnl_err *nfnl_err;
 252
 253         nfnl_err = kmalloc(sizeof(struct nfnl_err), GFP_KERNEL);
 254         if (nfnl_err == NULL)
 255                 return -ENOMEM;
 256
 257         nfnl_err->nlh = nlh;
 258         nfnl_err->err = err;
 259         nfnl_err->extack = *extack;
 260         list_add_tail(&nfnl_err->head, list);
 261
 262         return 0;
 263 }
 264
 265 static void nfnl_err_del(struct nfnl_err *nfnl_err)
 266 {
 267         list_del(&nfnl_err->head);
 268         kfree(nfnl_err);
 269 }
 270
 271 static void nfnl_err_reset(struct list_head *err_list)
 272 {
 273         struct nfnl_err *nfnl_err, *next;
 274
 275         list_for_each_entry_safe(nfnl_err, next, err_list, head)
 276                 nfnl_err_del(nfnl_err);
 277 }
 278
 279 static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb)
 280 {
 281         struct nfnl_err *nfnl_err, *next;
 282
 283         list_for_each_entry_safe(nfnl_err, next, err_list, head) {
 284                 netlink_ack(skb, nfnl_err->nlh, nfnl_err->err,
 285                             &nfnl_err->extack);
 286                 nfnl_err_del(nfnl_err);
 287         }
 288 }
 289
 290 enum {
 291         NFNL_BATCH_FAILURE      = (1 << 0),
 292         NFNL_BATCH_DONE         = (1 << 1),
 293         NFNL_BATCH_REPLAY       = (1 << 2),
 294 };
 295
 296 static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
 297                                 u16 subsys_id, u32 genid)
 298 {
 299         struct sk_buff *oskb = skb;
 300         struct net *net = sock_net(skb->sk);
 301         const struct nfnetlink_subsystem *ss;
 302         const struct nfnl_callback *nc;
 303         struct netlink_ext_ack extack;
 304         LIST_HEAD(err_list);
 305         u32 status;
 306         int err;
 307
 308         if (subsys_id >= NFNL_SUBSYS_COUNT)
 309                 return netlink_ack(skb, nlh, -EINVAL, NULL);
 310 replay:
 311         status = 0;
 312
 313         skb = netlink_skb_clone(oskb, GFP_KERNEL);
 314         if (!skb)
 315                 return netlink_ack(oskb, nlh, -ENOMEM, NULL);
 316
 317         nfnl_lock(subsys_id);
 318         ss = nfnl_dereference_protected(subsys_id);
 319         if (!ss) {
 320 #ifdef CONFIG_MODULES
 321                 nfnl_unlock(subsys_id);
 322                 request_module("nfnetlink-subsys-%d", subsys_id);
 323                 nfnl_lock(subsys_id);
 324                 ss = nfnl_dereference_protected(subsys_id);
 325                 if (!ss)
 326 #endif
 327                 {
 328                         nfnl_unlock(subsys_id);
 329                         netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
 330                         return kfree_skb(skb);
 331                 }
 332         }
 333
 334         if (!ss->valid_genid || !ss->commit || !ss->abort) {
 335                 nfnl_unlock(subsys_id);
 336                 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
 337                 return kfree_skb(skb);
 338         }
 339
 340         if (!try_module_get(ss->owner)) {
 341                 nfnl_unlock(subsys_id);
 342                 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
 343                 return kfree_skb(skb);
 344         }
 345
 346         if (!ss->valid_genid(net, genid)) {
 347                 module_put(ss->owner);
 348                 nfnl_unlock(subsys_id);
 349                 netlink_ack(oskb, nlh, -ERESTART, NULL);
 350                 return kfree_skb(skb);
 351         }
 352
 353         nfnl_unlock(subsys_id);
 354
 355         while (skb->len >= nlmsg_total_size(0)) {
 356                 int msglen, type;
 357
 358                 if (fatal_signal_pending(current)) {
 359                         nfnl_err_reset(&err_list);
 360                         err = -EINTR;
 361                         status = NFNL_BATCH_FAILURE;
 362                         goto done;
 363                 }
 364
 365                 memset(&extack, 0, sizeof(extack));
 366                 nlh = nlmsg_hdr(skb);
 367                 err = 0;
 368
 369                 if (nlh->nlmsg_len < NLMSG_HDRLEN ||
 370                     skb->len < nlh->nlmsg_len ||
 371                     nlmsg_len(nlh) < sizeof(struct nfgenmsg)) {
 372                         nfnl_err_reset(&err_list);
 373                         status |= NFNL_BATCH_FAILURE;
 374                         goto done;
 375                 }
 376
 377                 /* Only requests are handled by the kernel */
 378                 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) {
 379                         err = -EINVAL;
 380                         goto ack;
 381                 }
 382
 383                 type = nlh->nlmsg_type;
 384                 if (type == NFNL_MSG_BATCH_BEGIN) {
 385                         /* Malformed: Batch begin twice */
 386                         nfnl_err_reset(&err_list);
 387                         status |= NFNL_BATCH_FAILURE;
 388                         goto done;
 389                 } else if (type == NFNL_MSG_BATCH_END) {
 390                         status |= NFNL_BATCH_DONE;
 391                         goto done;
 392                 } else if (type < NLMSG_MIN_TYPE) {
 393                         err = -EINVAL;
 394                         goto ack;
 395                 }
 396
 397                 /* We only accept a batch with messages for the same
 398                  * subsystem.
 399                  */
 400                 if (NFNL_SUBSYS_ID(type) != subsys_id) {
 401                         err = -EINVAL;
 402                         goto ack;
 403                 }
 404
 405                 nc = nfnetlink_find_client(type, ss);
 406                 if (!nc) {
 407                         err = -EINVAL;
 408                         goto ack;
 409                 }
 410
 411                 {
 412                         int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
 413                         u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
 414                         struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
 415                         struct nlattr *attr = (void *)nlh + min_len;
 416                         int attrlen = nlh->nlmsg_len - min_len;
 417
 418                         /* Sanity-check NFTA_MAX_ATTR */
 419                         if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
 420                                 err = -ENOMEM;
 421                                 goto ack;
 422                         }
 423
 424                         err = nla_parse(cda, ss->cb[cb_id].attr_count, attr,
 425                                         attrlen, ss->cb[cb_id].policy, NULL);
 426                         if (err < 0)
 427                                 goto ack;
 428
 429                         if (nc->call_batch) {
 430                                 err = nc->call_batch(net, net->nfnl, skb, nlh,
 431                                                      (const struct nlattr **)cda,
 432                                                      &extack);
 433                         }
 434
 435                         /* The lock was released to autoload some module, we
 436                          * have to abort and start from scratch using the
 437                          * original skb.
 438                          */
 439                         if (err == -EAGAIN) {
 440                                 status |= NFNL_BATCH_REPLAY;
 441                                 goto done;
 442                         }
 443                 }
 444 ack:
 445                 if (nlh->nlmsg_flags & NLM_F_ACK || err) {
 446                         /* Errors are delivered once the full batch has been
 447                          * processed, this avoids that the same error is
 448                          * reported several times when replaying the batch.
 449                          */
 450                         if (nfnl_err_add(&err_list, nlh, err, &extack) < 0) {
 451                                 /* We failed to enqueue an error, reset the
 452                                  * list of errors and send OOM to userspace
 453                                  * pointing to the batch header.
 454                                  */
 455                                 nfnl_err_reset(&err_list);
 456                                 netlink_ack(oskb, nlmsg_hdr(oskb), -ENOMEM,
 457                                             NULL);
 458                                 status |= NFNL_BATCH_FAILURE;
 459                                 goto done;
 460                         }
 461                         /* We don't stop processing the batch on errors, thus,
 462                          * userspace gets all the errors that the batch
 463                          * triggers.
 464                          */
 465                         if (err)
 466                                 status |= NFNL_BATCH_FAILURE;
 467                 }
 468
 469                 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
 470                 if (msglen > skb->len)
 471                         msglen = skb->len;
 472                 skb_pull(skb, msglen);
 473         }
 474 done:
 475         if (status & NFNL_BATCH_REPLAY) {
 476                 ss->abort(net, oskb);
 477                 nfnl_err_reset(&err_list);
 478                 kfree_skb(skb);
 479                 module_put(ss->owner);
 480                 goto replay;
 481         } else if (status == NFNL_BATCH_DONE) {
 482                 err = ss->commit(net, oskb);
 483                 if (err == -EAGAIN) {
 484                         status |= NFNL_BATCH_REPLAY;
 485                         goto done;
 486                 } else if (err) {
 487                         ss->abort(net, oskb);
 488                         netlink_ack(oskb, nlmsg_hdr(oskb), err, NULL);
 489                 }
 490         } else {
 491                 ss->abort(net, oskb);
 492         }
 493         if (ss->cleanup)
 494                 ss->cleanup(net);
 495
 496         nfnl_err_deliver(&err_list, oskb);
 497         kfree_skb(skb);
 498         module_put(ss->owner);
 499 }
 500
 501 static const struct nla_policy nfnl_batch_policy[NFNL_BATCH_MAX + 1] = {
 502         [NFNL_BATCH_GENID]      = { .type = NLA_U32 },
 503 };
 504
 505 static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh)
 506 {
 507         int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
 508         struct nlattr *attr = (void *)nlh + min_len;
 509         struct nlattr *cda[NFNL_BATCH_MAX + 1];
 510         int attrlen = nlh->nlmsg_len - min_len;
 511         struct nfgenmsg *nfgenmsg;
 512         int msglen, err;
 513         u32 gen_id = 0;
 514         u16 res_id;
 515
 516         msglen = NLMSG_ALIGN(nlh->nlmsg_len);
 517         if (msglen > skb->len)
 518                 msglen = skb->len;
 519
 520         if (skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg))
 521                 return;
 522
 523         err = nla_parse(cda, NFNL_BATCH_MAX, attr, attrlen, nfnl_batch_policy,
 524                         NULL);
 525         if (err < 0) {
 526                 netlink_ack(skb, nlh, err, NULL);
 527                 return;
 528         }
 529         if (cda[NFNL_BATCH_GENID])
 530                 gen_id = ntohl(nla_get_be32(cda[NFNL_BATCH_GENID]));
 531
 532         nfgenmsg = nlmsg_data(nlh);
 533         skb_pull(skb, msglen);
 534         /* Work around old nft using host byte order */
 535         if (nfgenmsg->res_id == NFNL_SUBSYS_NFTABLES)
 536                 res_id = NFNL_SUBSYS_NFTABLES;
 537         else
 538                 res_id = ntohs(nfgenmsg->res_id);
 539
 540         nfnetlink_rcv_batch(skb, nlh, res_id, gen_id);
 541 }
 542
 543 static void nfnetlink_rcv(struct sk_buff *skb)
 544 {
 545         struct nlmsghdr *nlh = nlmsg_hdr(skb);
 546
 547         if (skb->len < NLMSG_HDRLEN ||
 548             nlh->nlmsg_len < NLMSG_HDRLEN ||
 549             skb->len < nlh->nlmsg_len)
 550                 return;
 551
 552         if (!netlink_net_capable(skb, CAP_NET_ADMIN)) {
 553                 netlink_ack(skb, nlh, -EPERM, NULL);
 554                 return;
 555         }
 556
 557         if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN)
 558                 nfnetlink_rcv_skb_batch(skb, nlh);
 559         else
 560                 netlink_rcv_skb(skb, nfnetlink_rcv_msg);
 561 }
 562
 563 #ifdef CONFIG_MODULES
 564 static int nfnetlink_bind(struct net *net, int group)
 565 {
 566         const struct nfnetlink_subsystem *ss;
 567         int type;
 568
 569         if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
 570                 return 0;
 571
 572         type = nfnl_group2type[group];
 573
 574         rcu_read_lock();
 575         ss = nfnetlink_get_subsys(type << 8);
 576         rcu_read_unlock();
 577         if (!ss)
 578                 request_module("nfnetlink-subsys-%d", type);
 579         return 0;
 580 }
 581 #endif
 582
 583 static int __net_init nfnetlink_net_init(struct net *net)
 584 {
 585         struct sock *nfnl;
 586         struct netlink_kernel_cfg cfg = {
 587                 .groups = NFNLGRP_MAX,
 588                 .input  = nfnetlink_rcv,
 589 #ifdef CONFIG_MODULES
 590                 .bind   = nfnetlink_bind,
 591 #endif
 592         };
 593
 594         nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg);
 595         if (!nfnl)
 596                 return -ENOMEM;
 597         net->nfnl_stash = nfnl;
 598         rcu_assign_pointer(net->nfnl, nfnl);
 599         return 0;
 600 }
 601
 602 static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
 603 {
 604         struct net *net;
 605
 606         list_for_each_entry(net, net_exit_list, exit_list)
 607                 RCU_INIT_POINTER(net->nfnl, NULL);
 608         synchronize_net();
 609         list_for_each_entry(net, net_exit_list, exit_list)
 610                 netlink_kernel_release(net->nfnl_stash);
 611 }
 612
 613 static struct pernet_operations nfnetlink_net_ops = {
 614         .init           = nfnetlink_net_init,
 615         .exit_batch     = nfnetlink_net_exit_batch,
 616 };
 617
 618 static int __init nfnetlink_init(void)
 619 {
 620         int i;
 621
 622         for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++)
 623                 BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE);
 624
 625         for (i=0; i<NFNL_SUBSYS_COUNT; i++)
 626                 mutex_init(&table[i].mutex);
 627
 628         return register_pernet_subsys(&nfnetlink_net_ops);
 629 }
 630
 631 static void __exit nfnetlink_exit(void)
 632 {
 633         unregister_pernet_subsys(&nfnetlink_net_ops);
 634 }
 635 module_init(nfnetlink_init);
 636 module_exit(nfnetlink_exit);