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 MODULE_DESCRIPTION("Netfilter messages via netlink socket");
  37
  38 #define nfnl_dereference_protected(id) \
  39         rcu_dereference_protected(table[(id)].subsys, \
  40                                   lockdep_nfnl_is_held((id)))
  41
  42 #define NFNL_MAX_ATTR_COUNT     32
  43
  44 static struct {
  45         struct mutex                            mutex;
  46         const struct nfnetlink_subsystem __rcu  *subsys;
  47 } table[NFNL_SUBSYS_COUNT];
  48
  49 static const int nfnl_group2type[NFNLGRP_MAX+1] = {
  50         [NFNLGRP_CONNTRACK_NEW]         = NFNL_SUBSYS_CTNETLINK,
  51         [NFNLGRP_CONNTRACK_UPDATE]      = NFNL_SUBSYS_CTNETLINK,
  52         [NFNLGRP_CONNTRACK_DESTROY]     = NFNL_SUBSYS_CTNETLINK,
  53         [NFNLGRP_CONNTRACK_EXP_NEW]     = NFNL_SUBSYS_CTNETLINK_EXP,
  54         [NFNLGRP_CONNTRACK_EXP_UPDATE]  = NFNL_SUBSYS_CTNETLINK_EXP,
  55         [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP,
  56         [NFNLGRP_NFTABLES]              = NFNL_SUBSYS_NFTABLES,
  57         [NFNLGRP_ACCT_QUOTA]            = NFNL_SUBSYS_ACCT,
  58         [NFNLGRP_NFTRACE]               = NFNL_SUBSYS_NFTABLES,
  59 };
  60
  61 void nfnl_lock(__u8 subsys_id)
  62 {
  63         mutex_lock(&table[subsys_id].mutex);
  64 }
  65 EXPORT_SYMBOL_GPL(nfnl_lock);
  66
  67 void nfnl_unlock(__u8 subsys_id)
  68 {
  69         mutex_unlock(&table[subsys_id].mutex);
  70 }
  71 EXPORT_SYMBOL_GPL(nfnl_unlock);
  72
  73 #ifdef CONFIG_PROVE_LOCKING
  74 bool lockdep_nfnl_is_held(u8 subsys_id)
  75 {
  76         return lockdep_is_held(&table[subsys_id].mutex);
  77 }
  78 EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held);
  79 #endif
  80
  81 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
  82 {
  83         u8 cb_id;
  84
  85         /* Sanity-check attr_count size to avoid stack buffer overflow. */
  86         for (cb_id = 0; cb_id < n->cb_count; cb_id++)
  87                 if (WARN_ON(n->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT))
  88                         return -EINVAL;
  89
  90         nfnl_lock(n->subsys_id);
  91         if (table[n->subsys_id].subsys) {
  92                 nfnl_unlock(n->subsys_id);
  93                 return -EBUSY;
  94         }
  95         rcu_assign_pointer(table[n->subsys_id].subsys, n);
  96         nfnl_unlock(n->subsys_id);
  97
  98         return 0;
  99 }
 100 EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
 101
 102 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
 103 {
 104         nfnl_lock(n->subsys_id);
 105         table[n->subsys_id].subsys = NULL;
 106         nfnl_unlock(n->subsys_id);
 107         synchronize_rcu();
 108         return 0;
 109 }
 110 EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
 111
 112 static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u16 type)
 113 {
 114         u8 subsys_id = NFNL_SUBSYS_ID(type);
 115
 116         if (subsys_id >= NFNL_SUBSYS_COUNT)
 117                 return NULL;
 118
 119         return rcu_dereference(table[subsys_id].subsys);
 120 }
 121
 122 static inline const struct nfnl_callback *
 123 nfnetlink_find_client(u16 type, const struct nfnetlink_subsystem *ss)
 124 {
 125         u8 cb_id = NFNL_MSG_TYPE(type);
 126
 127         if (cb_id >= ss->cb_count)
 128                 return NULL;
 129
 130         return &ss->cb[cb_id];
 131 }
 132
 133 int nfnetlink_has_listeners(struct net *net, unsigned int group)
 134 {
 135         return netlink_has_listeners(net->nfnl, group);
 136 }
 137 EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
 138
 139 int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid,
 140                    unsigned int group, int echo, gfp_t flags)
 141 {
 142         return nlmsg_notify(net->nfnl, skb, portid, group, echo, flags);
 143 }
 144 EXPORT_SYMBOL_GPL(nfnetlink_send);
 145
 146 int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error)
 147 {
 148         return netlink_set_err(net->nfnl, portid, group, error);
 149 }
 150 EXPORT_SYMBOL_GPL(nfnetlink_set_err);
 151
 152 int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid,
 153                       int flags)
 154 {
 155         return netlink_unicast(net->nfnl, skb, portid, flags);
 156 }
 157 EXPORT_SYMBOL_GPL(nfnetlink_unicast);
 158
 159 /* Process one complete nfnetlink message. */
 160 static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 161                              struct netlink_ext_ack *extack)
 162 {
 163         struct net *net = sock_net(skb->sk);
 164         const struct nfnl_callback *nc;
 165         const struct nfnetlink_subsystem *ss;
 166         int type, err;
 167
 168         /* All the messages must at least contain nfgenmsg */
 169         if (nlmsg_len(nlh) < sizeof(struct nfgenmsg))
 170                 return 0;
 171
 172         type = nlh->nlmsg_type;
 173 replay:
 174         rcu_read_lock();
 175         ss = nfnetlink_get_subsys(type);
 176         if (!ss) {
 177 #ifdef CONFIG_MODULES
 178                 rcu_read_unlock();
 179                 request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
 180                 rcu_read_lock();
 181                 ss = nfnetlink_get_subsys(type);
 182                 if (!ss)
 183 #endif
 184                 {
 185                         rcu_read_unlock();
 186                         return -EINVAL;
 187                 }
 188         }
 189
 190         nc = nfnetlink_find_client(type, ss);
 191         if (!nc) {
 192                 rcu_read_unlock();
 193                 return -EINVAL;
 194         }
 195
 196         {
 197                 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
 198                 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
 199                 struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
 200                 struct nlattr *attr = (void *)nlh + min_len;
 201                 int attrlen = nlh->nlmsg_len - min_len;
 202                 __u8 subsys_id = NFNL_SUBSYS_ID(type);
 203
 204                 /* Sanity-check NFNL_MAX_ATTR_COUNT */
 205                 if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
 206                         rcu_read_unlock();
 207                         return -ENOMEM;
 208                 }
 209
 210                 err = nla_parse_deprecated(cda, ss->cb[cb_id].attr_count,
 211                                            attr, attrlen,
 212                                            ss->cb[cb_id].policy, extack);
 213                 if (err < 0) {
 214                         rcu_read_unlock();
 215                         return err;
 216                 }
 217
 218                 if (nc->call_rcu) {
 219                         err = nc->call_rcu(net, net->nfnl, skb, nlh,
 220                                            (const struct nlattr **)cda,
 221                                            extack);
 222                         rcu_read_unlock();
 223                 } else {
 224                         rcu_read_unlock();
 225                         nfnl_lock(subsys_id);
 226                         if (nfnl_dereference_protected(subsys_id) != ss ||
 227                             nfnetlink_find_client(type, ss) != nc)
 228                                 err = -EAGAIN;
 229                         else if (nc->call)
 230                                 err = nc->call(net, net->nfnl, skb, nlh,
 231                                                (const struct nlattr **)cda,
 232                                                extack);
 233                         else
 234                                 err = -EINVAL;
 235                         nfnl_unlock(subsys_id);
 236                 }
 237                 if (err == -EAGAIN)
 238                         goto replay;
 239                 return err;
 240         }
 241 }
 242
 243 struct nfnl_err {
 244         struct list_head        head;
 245         struct nlmsghdr         *nlh;
 246         int                     err;
 247         struct netlink_ext_ack  extack;
 248 };
 249
 250 static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err,
 251                         const struct netlink_ext_ack *extack)
 252 {
 253         struct nfnl_err *nfnl_err;
 254
 255         nfnl_err = kmalloc(sizeof(struct nfnl_err), GFP_KERNEL);
 256         if (nfnl_err == NULL)
 257                 return -ENOMEM;
 258
 259         nfnl_err->nlh = nlh;
 260         nfnl_err->err = err;
 261         nfnl_err->extack = *extack;
 262         list_add_tail(&nfnl_err->head, list);
 263
 264         return 0;
 265 }
 266
 267 static void nfnl_err_del(struct nfnl_err *nfnl_err)
 268 {
 269         list_del(&nfnl_err->head);
 270         kfree(nfnl_err);
 271 }
 272
 273 static void nfnl_err_reset(struct list_head *err_list)
 274 {
 275         struct nfnl_err *nfnl_err, *next;
 276
 277         list_for_each_entry_safe(nfnl_err, next, err_list, head)
 278                 nfnl_err_del(nfnl_err);
 279 }
 280
 281 static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb)
 282 {
 283         struct nfnl_err *nfnl_err, *next;
 284
 285         list_for_each_entry_safe(nfnl_err, next, err_list, head) {
 286                 netlink_ack(skb, nfnl_err->nlh, nfnl_err->err,
 287                             &nfnl_err->extack);
 288                 nfnl_err_del(nfnl_err);
 289         }
 290 }
 291
 292 enum {
 293         NFNL_BATCH_FAILURE      = (1 << 0),
 294         NFNL_BATCH_DONE         = (1 << 1),
 295         NFNL_BATCH_REPLAY       = (1 << 2),
 296 };
 297
 298 static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
 299                                 u16 subsys_id, u32 genid)
 300 {
 301         struct sk_buff *oskb = skb;
 302         struct net *net = sock_net(skb->sk);
 303         const struct nfnetlink_subsystem *ss;
 304         const struct nfnl_callback *nc;
 305         struct netlink_ext_ack extack;
 306         LIST_HEAD(err_list);
 307         u32 status;
 308         int err;
 309
 310         if (subsys_id >= NFNL_SUBSYS_COUNT)
 311                 return netlink_ack(skb, nlh, -EINVAL, NULL);
 312 replay:
 313         status = 0;
 314
 315         skb = netlink_skb_clone(oskb, GFP_KERNEL);
 316         if (!skb)
 317                 return netlink_ack(oskb, nlh, -ENOMEM, NULL);
 318
 319         nfnl_lock(subsys_id);
 320         ss = nfnl_dereference_protected(subsys_id);
 321         if (!ss) {
 322 #ifdef CONFIG_MODULES
 323                 nfnl_unlock(subsys_id);
 324                 request_module("nfnetlink-subsys-%d", subsys_id);
 325                 nfnl_lock(subsys_id);
 326                 ss = nfnl_dereference_protected(subsys_id);
 327                 if (!ss)
 328 #endif
 329                 {
 330                         nfnl_unlock(subsys_id);
 331                         netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
 332                         return kfree_skb(skb);
 333                 }
 334         }
 335
 336         if (!ss->valid_genid || !ss->commit || !ss->abort) {
 337                 nfnl_unlock(subsys_id);
 338                 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
 339                 return kfree_skb(skb);
 340         }
 341
 342         if (!try_module_get(ss->owner)) {
 343                 nfnl_unlock(subsys_id);
 344                 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
 345                 return kfree_skb(skb);
 346         }
 347
 348         if (!ss->valid_genid(net, genid)) {
 349                 module_put(ss->owner);
 350                 nfnl_unlock(subsys_id);
 351                 netlink_ack(oskb, nlh, -ERESTART, NULL);
 352                 return kfree_skb(skb);
 353         }
 354
 355         nfnl_unlock(subsys_id);
 356
 357         while (skb->len >= nlmsg_total_size(0)) {
 358                 int msglen, type;
 359
 360                 if (fatal_signal_pending(current)) {
 361                         nfnl_err_reset(&err_list);
 362                         err = -EINTR;
 363                         status = NFNL_BATCH_FAILURE;
 364                         goto done;
 365                 }
 366
 367                 memset(&extack, 0, sizeof(extack));
 368                 nlh = nlmsg_hdr(skb);
 369                 err = 0;
 370
 371                 if (nlh->nlmsg_len < NLMSG_HDRLEN ||
 372                     skb->len < nlh->nlmsg_len ||
 373                     nlmsg_len(nlh) < sizeof(struct nfgenmsg)) {
 374                         nfnl_err_reset(&err_list);
 375                         status |= NFNL_BATCH_FAILURE;
 376                         goto done;
 377                 }
 378
 379                 /* Only requests are handled by the kernel */
 380                 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) {
 381                         err = -EINVAL;
 382                         goto ack;
 383                 }
 384
 385                 type = nlh->nlmsg_type;
 386                 if (type == NFNL_MSG_BATCH_BEGIN) {
 387                         /* Malformed: Batch begin twice */
 388                         nfnl_err_reset(&err_list);
 389                         status |= NFNL_BATCH_FAILURE;
 390                         goto done;
 391                 } else if (type == NFNL_MSG_BATCH_END) {
 392                         status |= NFNL_BATCH_DONE;
 393                         goto done;
 394                 } else if (type < NLMSG_MIN_TYPE) {
 395                         err = -EINVAL;
 396                         goto ack;
 397                 }
 398
 399                 /* We only accept a batch with messages for the same
 400                  * subsystem.
 401                  */
 402                 if (NFNL_SUBSYS_ID(type) != subsys_id) {
 403                         err = -EINVAL;
 404                         goto ack;
 405                 }
 406
 407                 nc = nfnetlink_find_client(type, ss);
 408                 if (!nc) {
 409                         err = -EINVAL;
 410                         goto ack;
 411                 }
 412
 413                 {
 414                         int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
 415                         u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
 416                         struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
 417                         struct nlattr *attr = (void *)nlh + min_len;
 418                         int attrlen = nlh->nlmsg_len - min_len;
 419
 420                         /* Sanity-check NFTA_MAX_ATTR */
 421                         if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
 422                                 err = -ENOMEM;
 423                                 goto ack;
 424                         }
 425
 426                         err = nla_parse_deprecated(cda,
 427                                                    ss->cb[cb_id].attr_count,
 428                                                    attr, attrlen,
 429                                                    ss->cb[cb_id].policy, NULL);
 430                         if (err < 0)
 431                                 goto ack;
 432
 433                         if (nc->call_batch) {
 434                                 err = nc->call_batch(net, net->nfnl, skb, nlh,
 435                                                      (const struct nlattr **)cda,
 436                                                      &extack);
 437                         }
 438
 439                         /* The lock was released to autoload some module, we
 440                          * have to abort and start from scratch using the
 441                          * original skb.
 442                          */
 443                         if (err == -EAGAIN) {
 444                                 status |= NFNL_BATCH_REPLAY;
 445                                 goto done;
 446                         }
 447                 }
 448 ack:
 449                 if (nlh->nlmsg_flags & NLM_F_ACK || err) {
 450                         /* Errors are delivered once the full batch has been
 451                          * processed, this avoids that the same error is
 452                          * reported several times when replaying the batch.
 453                          */
 454                         if (nfnl_err_add(&err_list, nlh, err, &extack) < 0) {
 455                                 /* We failed to enqueue an error, reset the
 456                                  * list of errors and send OOM to userspace
 457                                  * pointing to the batch header.
 458                                  */
 459                                 nfnl_err_reset(&err_list);
 460                                 netlink_ack(oskb, nlmsg_hdr(oskb), -ENOMEM,
 461                                             NULL);
 462                                 status |= NFNL_BATCH_FAILURE;
 463                                 goto done;
 464                         }
 465                         /* We don't stop processing the batch on errors, thus,
 466                          * userspace gets all the errors that the batch
 467                          * triggers.
 468                          */
 469                         if (err)
 470                                 status |= NFNL_BATCH_FAILURE;
 471                 }
 472
 473                 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
 474                 if (msglen > skb->len)
 475                         msglen = skb->len;
 476                 skb_pull(skb, msglen);
 477         }
 478 done:
 479         if (status & NFNL_BATCH_REPLAY) {
 480                 ss->abort(net, oskb, true);
 481                 nfnl_err_reset(&err_list);
 482                 kfree_skb(skb);
 483                 module_put(ss->owner);
 484                 goto replay;
 485         } else if (status == NFNL_BATCH_DONE) {
 486                 err = ss->commit(net, oskb);
 487                 if (err == -EAGAIN) {
 488                         status |= NFNL_BATCH_REPLAY;
 489                         goto done;
 490                 } else if (err) {
 491                         ss->abort(net, oskb, false);
 492                         netlink_ack(oskb, nlmsg_hdr(oskb), err, NULL);
 493                 }
 494         } else {
 495                 ss->abort(net, oskb, false);
 496         }
 497         if (ss->cleanup)
 498                 ss->cleanup(net);
 499
 500         nfnl_err_deliver(&err_list, oskb);
 501         kfree_skb(skb);
 502         module_put(ss->owner);
 503 }
 504
 505 static const struct nla_policy nfnl_batch_policy[NFNL_BATCH_MAX + 1] = {
 506         [NFNL_BATCH_GENID]      = { .type = NLA_U32 },
 507 };
 508
 509 static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh)
 510 {
 511         int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
 512         struct nlattr *attr = (void *)nlh + min_len;
 513         struct nlattr *cda[NFNL_BATCH_MAX + 1];
 514         int attrlen = nlh->nlmsg_len - min_len;
 515         struct nfgenmsg *nfgenmsg;
 516         int msglen, err;
 517         u32 gen_id = 0;
 518         u16 res_id;
 519
 520         msglen = NLMSG_ALIGN(nlh->nlmsg_len);
 521         if (msglen > skb->len)
 522                 msglen = skb->len;
 523
 524         if (skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg))
 525                 return;
 526
 527         err = nla_parse_deprecated(cda, NFNL_BATCH_MAX, attr, attrlen,
 528                                    nfnl_batch_policy, NULL);
 529         if (err < 0) {
 530                 netlink_ack(skb, nlh, err, NULL);
 531                 return;
 532         }
 533         if (cda[NFNL_BATCH_GENID])
 534                 gen_id = ntohl(nla_get_be32(cda[NFNL_BATCH_GENID]));
 535
 536         nfgenmsg = nlmsg_data(nlh);
 537         skb_pull(skb, msglen);
 538         /* Work around old nft using host byte order */
 539         if (nfgenmsg->res_id == NFNL_SUBSYS_NFTABLES)
 540                 res_id = NFNL_SUBSYS_NFTABLES;
 541         else
 542                 res_id = ntohs(nfgenmsg->res_id);
 543
 544         nfnetlink_rcv_batch(skb, nlh, res_id, gen_id);
 545 }
 546
 547 static void nfnetlink_rcv(struct sk_buff *skb)
 548 {
 549         struct nlmsghdr *nlh = nlmsg_hdr(skb);
 550
 551         if (skb->len < NLMSG_HDRLEN ||
 552             nlh->nlmsg_len < NLMSG_HDRLEN ||
 553             skb->len < nlh->nlmsg_len)
 554                 return;
 555
 556         if (!netlink_net_capable(skb, CAP_NET_ADMIN)) {
 557                 netlink_ack(skb, nlh, -EPERM, NULL);
 558                 return;
 559         }
 560
 561         if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN)
 562                 nfnetlink_rcv_skb_batch(skb, nlh);
 563         else
 564                 netlink_rcv_skb(skb, nfnetlink_rcv_msg);
 565 }
 566
 567 #ifdef CONFIG_MODULES
 568 static int nfnetlink_bind(struct net *net, int group)
 569 {
 570         const struct nfnetlink_subsystem *ss;
 571         int type;
 572
 573         if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
 574                 return 0;
 575
 576         type = nfnl_group2type[group];
 577
 578         rcu_read_lock();
 579         ss = nfnetlink_get_subsys(type << 8);
 580         rcu_read_unlock();
 581         if (!ss)
 582                 request_module_nowait("nfnetlink-subsys-%d", type);
 583         return 0;
 584 }
 585 #endif
 586
 587 static int __net_init nfnetlink_net_init(struct net *net)
 588 {
 589         struct sock *nfnl;
 590         struct netlink_kernel_cfg cfg = {
 591                 .groups = NFNLGRP_MAX,
 592                 .input  = nfnetlink_rcv,
 593 #ifdef CONFIG_MODULES
 594                 .bind   = nfnetlink_bind,
 595 #endif
 596         };
 597
 598         nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg);
 599         if (!nfnl)
 600                 return -ENOMEM;
 601         net->nfnl_stash = nfnl;
 602         rcu_assign_pointer(net->nfnl, nfnl);
 603         return 0;
 604 }
 605
 606 static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
 607 {
 608         struct net *net;
 609
 610         list_for_each_entry(net, net_exit_list, exit_list)
 611                 RCU_INIT_POINTER(net->nfnl, NULL);
 612         synchronize_net();
 613         list_for_each_entry(net, net_exit_list, exit_list)
 614                 netlink_kernel_release(net->nfnl_stash);
 615 }
 616
 617 static struct pernet_operations nfnetlink_net_ops = {
 618         .init           = nfnetlink_net_init,
 619         .exit_batch     = nfnetlink_net_exit_batch,
 620 };
 621
 622 static int __init nfnetlink_init(void)
 623 {
 624         int i;
 625
 626         for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++)
 627                 BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE);
 628
 629         for (i=0; i<NFNL_SUBSYS_COUNT; i++)
 630                 mutex_init(&table[i].mutex);
 631
 632         return register_pernet_subsys(&nfnetlink_net_ops);
 633 }
 634
 635 static void __exit nfnetlink_exit(void)
 636 {
 637         unregister_pernet_subsys(&nfnetlink_net_ops);
 638 }
 639 module_init(nfnetlink_init);
 640 module_exit(nfnetlink_exit);