Pileus Git - ~andy/linux/blob - net/netfilter/nfnetlink_cthelper.c

   1 /*
   2  * (C) 2012 Pablo Neira Ayuso <pablo@netfilter.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation (or any later at your option).
   7  *
   8  * This software has been sponsored by Vyatta Inc. <http://www.vyatta.com>
   9  */
  10 #include <linux/init.h>
  11 #include <linux/module.h>
  12 #include <linux/kernel.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/netlink.h>
  15 #include <linux/rculist.h>
  16 #include <linux/slab.h>
  17 #include <linux/types.h>
  18 #include <linux/list.h>
  19 #include <linux/errno.h>
  20 #include <net/netlink.h>
  21 #include <net/sock.h>
  22
  23 #include <net/netfilter/nf_conntrack_helper.h>
  24 #include <net/netfilter/nf_conntrack_expect.h>
  25 #include <net/netfilter/nf_conntrack_ecache.h>
  26
  27 #include <linux/netfilter/nfnetlink.h>
  28 #include <linux/netfilter/nfnetlink_conntrack.h>
  29 #include <linux/netfilter/nfnetlink_cthelper.h>
  30
  31 MODULE_LICENSE("GPL");
  32 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
  33 MODULE_DESCRIPTION("nfnl_cthelper: User-space connection tracking helpers");
  34
  35 static int
  36 nfnl_userspace_cthelper(struct sk_buff *skb, unsigned int protoff,
  37                         struct nf_conn *ct, enum ip_conntrack_info ctinfo)
  38 {
  39         const struct nf_conn_help *help;
  40         struct nf_conntrack_helper *helper;
  41
  42         help = nfct_help(ct);
  43         if (help == NULL)
  44                 return NF_DROP;
  45
  46         /* rcu_read_lock()ed by nf_hook_slow */
  47         helper = rcu_dereference(help->helper);
  48         if (helper == NULL)
  49                 return NF_DROP;
  50
  51         /* This is an user-space helper not yet configured, skip. */
  52         if ((helper->flags &
  53             (NF_CT_HELPER_F_USERSPACE | NF_CT_HELPER_F_CONFIGURED)) ==
  54              NF_CT_HELPER_F_USERSPACE)
  55                 return NF_ACCEPT;
  56
  57         /* If the user-space helper is not available, don't block traffic. */
  58         return NF_QUEUE_NR(helper->queue_num) | NF_VERDICT_FLAG_QUEUE_BYPASS;
  59 }
  60
  61 static const struct nla_policy nfnl_cthelper_tuple_pol[NFCTH_TUPLE_MAX+1] = {
  62         [NFCTH_TUPLE_L3PROTONUM] = { .type = NLA_U16, },
  63         [NFCTH_TUPLE_L4PROTONUM] = { .type = NLA_U8, },
  64 };
  65
  66 static int
  67 nfnl_cthelper_parse_tuple(struct nf_conntrack_tuple *tuple,
  68                           const struct nlattr *attr)
  69 {
  70         struct nlattr *tb[NFCTH_TUPLE_MAX+1];
  71
  72         nla_parse_nested(tb, NFCTH_TUPLE_MAX, attr, nfnl_cthelper_tuple_pol);
  73
  74         if (!tb[NFCTH_TUPLE_L3PROTONUM] || !tb[NFCTH_TUPLE_L4PROTONUM])
  75                 return -EINVAL;
  76
  77         tuple->src.l3num = ntohs(nla_get_be16(tb[NFCTH_TUPLE_L3PROTONUM]));
  78         tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]);
  79
  80         return 0;
  81 }
  82
  83 static int
  84 nfnl_cthelper_from_nlattr(struct nlattr *attr, struct nf_conn *ct)
  85 {
  86         const struct nf_conn_help *help = nfct_help(ct);
  87
  88         if (attr == NULL)
  89                 return -EINVAL;
  90
  91         if (help->helper->data_len == 0)
  92                 return -EINVAL;
  93
  94         memcpy(&help->data, nla_data(attr), help->helper->data_len);
  95         return 0;
  96 }
  97
  98 static int
  99 nfnl_cthelper_to_nlattr(struct sk_buff *skb, const struct nf_conn *ct)
 100 {
 101         const struct nf_conn_help *help = nfct_help(ct);
 102
 103         if (help->helper->data_len &&
 104             nla_put(skb, CTA_HELP_INFO, help->helper->data_len, &help->data))
 105                 goto nla_put_failure;
 106
 107         return 0;
 108
 109 nla_put_failure:
 110         return -ENOSPC;
 111 }
 112
 113 static const struct nla_policy nfnl_cthelper_expect_pol[NFCTH_POLICY_MAX+1] = {
 114         [NFCTH_POLICY_NAME] = { .type = NLA_NUL_STRING,
 115                                 .len = NF_CT_HELPER_NAME_LEN-1 },
 116         [NFCTH_POLICY_EXPECT_MAX] = { .type = NLA_U32, },
 117         [NFCTH_POLICY_EXPECT_TIMEOUT] = { .type = NLA_U32, },
 118 };
 119
 120 static int
 121 nfnl_cthelper_expect_policy(struct nf_conntrack_expect_policy *expect_policy,
 122                             const struct nlattr *attr)
 123 {
 124         struct nlattr *tb[NFCTH_POLICY_MAX+1];
 125
 126         nla_parse_nested(tb, NFCTH_POLICY_MAX, attr, nfnl_cthelper_expect_pol);
 127
 128         if (!tb[NFCTH_POLICY_NAME] ||
 129             !tb[NFCTH_POLICY_EXPECT_MAX] ||
 130             !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
 131                 return -EINVAL;
 132
 133         strncpy(expect_policy->name,
 134                 nla_data(tb[NFCTH_POLICY_NAME]), NF_CT_HELPER_NAME_LEN);
 135         expect_policy->max_expected =
 136                 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
 137         expect_policy->timeout =
 138                 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
 139
 140         return 0;
 141 }
 142
 143 static const struct nla_policy
 144 nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = {
 145         [NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, },
 146 };
 147
 148 static int
 149 nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
 150                                   const struct nlattr *attr)
 151 {
 152         int i, ret;
 153         struct nf_conntrack_expect_policy *expect_policy;
 154         struct nlattr *tb[NFCTH_POLICY_SET_MAX+1];
 155
 156         nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
 157                                         nfnl_cthelper_expect_policy_set);
 158
 159         if (!tb[NFCTH_POLICY_SET_NUM])
 160                 return -EINVAL;
 161
 162         helper->expect_class_max =
 163                 ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
 164
 165         if (helper->expect_class_max != 0 &&
 166             helper->expect_class_max > NF_CT_MAX_EXPECT_CLASSES)
 167                 return -EOVERFLOW;
 168
 169         expect_policy = kzalloc(sizeof(struct nf_conntrack_expect_policy) *
 170                                 helper->expect_class_max, GFP_KERNEL);
 171         if (expect_policy == NULL)
 172                 return -ENOMEM;
 173
 174         for (i=0; i<helper->expect_class_max; i++) {
 175                 if (!tb[NFCTH_POLICY_SET+i])
 176                         goto err;
 177
 178                 ret = nfnl_cthelper_expect_policy(&expect_policy[i],
 179                                                   tb[NFCTH_POLICY_SET+i]);
 180                 if (ret < 0)
 181                         goto err;
 182         }
 183         helper->expect_policy = expect_policy;
 184         return 0;
 185 err:
 186         kfree(expect_policy);
 187         return -EINVAL;
 188 }
 189
 190 static int
 191 nfnl_cthelper_create(const struct nlattr * const tb[],
 192                      struct nf_conntrack_tuple *tuple)
 193 {
 194         struct nf_conntrack_helper *helper;
 195         int ret;
 196
 197         if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN])
 198                 return -EINVAL;
 199
 200         helper = kzalloc(sizeof(struct nf_conntrack_helper), GFP_KERNEL);
 201         if (helper == NULL)
 202                 return -ENOMEM;
 203
 204         ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]);
 205         if (ret < 0)
 206                 goto err;
 207
 208         strncpy(helper->name, nla_data(tb[NFCTH_NAME]), NF_CT_HELPER_NAME_LEN);
 209         helper->data_len = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
 210         helper->flags |= NF_CT_HELPER_F_USERSPACE;
 211         memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
 212
 213         helper->me = THIS_MODULE;
 214         helper->help = nfnl_userspace_cthelper;
 215         helper->from_nlattr = nfnl_cthelper_from_nlattr;
 216         helper->to_nlattr = nfnl_cthelper_to_nlattr;
 217
 218         /* Default to queue number zero, this can be updated at any time. */
 219         if (tb[NFCTH_QUEUE_NUM])
 220                 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
 221
 222         if (tb[NFCTH_STATUS]) {
 223                 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
 224
 225                 switch(status) {
 226                 case NFCT_HELPER_STATUS_ENABLED:
 227                         helper->flags |= NF_CT_HELPER_F_CONFIGURED;
 228                         break;
 229                 case NFCT_HELPER_STATUS_DISABLED:
 230                         helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
 231                         break;
 232                 }
 233         }
 234
 235         ret = nf_conntrack_helper_register(helper);
 236         if (ret < 0)
 237                 goto err;
 238
 239         return 0;
 240 err:
 241         kfree(helper);
 242         return ret;
 243 }
 244
 245 static int
 246 nfnl_cthelper_update(const struct nlattr * const tb[],
 247                      struct nf_conntrack_helper *helper)
 248 {
 249         int ret;
 250
 251         if (tb[NFCTH_PRIV_DATA_LEN])
 252                 return -EBUSY;
 253
 254         if (tb[NFCTH_POLICY]) {
 255                 ret = nfnl_cthelper_parse_expect_policy(helper,
 256                                                         tb[NFCTH_POLICY]);
 257                 if (ret < 0)
 258                         return ret;
 259         }
 260         if (tb[NFCTH_QUEUE_NUM])
 261                 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
 262
 263         if (tb[NFCTH_STATUS]) {
 264                 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
 265
 266                 switch(status) {
 267                 case NFCT_HELPER_STATUS_ENABLED:
 268                         helper->flags |= NF_CT_HELPER_F_CONFIGURED;
 269                         break;
 270                 case NFCT_HELPER_STATUS_DISABLED:
 271                         helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
 272                         break;
 273                 }
 274         }
 275         return 0;
 276 }
 277
 278 static int
 279 nfnl_cthelper_new(struct sock *nfnl, struct sk_buff *skb,
 280                   const struct nlmsghdr *nlh, const struct nlattr * const tb[])
 281 {
 282         const char *helper_name;
 283         struct nf_conntrack_helper *cur, *helper = NULL;
 284         struct nf_conntrack_tuple tuple;
 285         struct hlist_node *n;
 286         int ret = 0, i;
 287
 288         if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE])
 289                 return -EINVAL;
 290
 291         helper_name = nla_data(tb[NFCTH_NAME]);
 292
 293         ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
 294         if (ret < 0)
 295                 return ret;
 296
 297         rcu_read_lock();
 298         for (i = 0; i < nf_ct_helper_hsize && !helper; i++) {
 299                 hlist_for_each_entry_rcu(cur, n, &nf_ct_helper_hash[i], hnode) {
 300
 301                         /* skip non-userspace conntrack helpers. */
 302                         if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 303                                 continue;
 304
 305                         if (strncmp(cur->name, helper_name,
 306                                         NF_CT_HELPER_NAME_LEN) != 0)
 307                                 continue;
 308
 309                         if ((tuple.src.l3num != cur->tuple.src.l3num ||
 310                              tuple.dst.protonum != cur->tuple.dst.protonum))
 311                                 continue;
 312
 313                         if (nlh->nlmsg_flags & NLM_F_EXCL) {
 314                                 ret = -EEXIST;
 315                                 goto err;
 316                         }
 317                         helper = cur;
 318                         break;
 319                 }
 320         }
 321         rcu_read_unlock();
 322
 323         if (helper == NULL)
 324                 ret = nfnl_cthelper_create(tb, &tuple);
 325         else
 326                 ret = nfnl_cthelper_update(tb, helper);
 327
 328         return ret;
 329 err:
 330         rcu_read_unlock();
 331         return ret;
 332 }
 333
 334 static int
 335 nfnl_cthelper_dump_tuple(struct sk_buff *skb,
 336                          struct nf_conntrack_helper *helper)
 337 {
 338         struct nlattr *nest_parms;
 339
 340         nest_parms = nla_nest_start(skb, NFCTH_TUPLE | NLA_F_NESTED);
 341         if (nest_parms == NULL)
 342                 goto nla_put_failure;
 343
 344         if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
 345                          htons(helper->tuple.src.l3num)))
 346                 goto nla_put_failure;
 347
 348         if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
 349                 goto nla_put_failure;
 350
 351         nla_nest_end(skb, nest_parms);
 352         return 0;
 353
 354 nla_put_failure:
 355         return -1;
 356 }
 357
 358 static int
 359 nfnl_cthelper_dump_policy(struct sk_buff *skb,
 360                         struct nf_conntrack_helper *helper)
 361 {
 362         int i;
 363         struct nlattr *nest_parms1, *nest_parms2;
 364
 365         nest_parms1 = nla_nest_start(skb, NFCTH_POLICY | NLA_F_NESTED);
 366         if (nest_parms1 == NULL)
 367                 goto nla_put_failure;
 368
 369         if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
 370                          htonl(helper->expect_class_max)))
 371                 goto nla_put_failure;
 372
 373         for (i=0; i<helper->expect_class_max; i++) {
 374                 nest_parms2 = nla_nest_start(skb,
 375                                 (NFCTH_POLICY_SET+i) | NLA_F_NESTED);
 376                 if (nest_parms2 == NULL)
 377                         goto nla_put_failure;
 378
 379                 if (nla_put_string(skb, NFCTH_POLICY_NAME,
 380                                    helper->expect_policy[i].name))
 381                         goto nla_put_failure;
 382
 383                 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
 384                                  htonl(helper->expect_policy[i].max_expected)))
 385                         goto nla_put_failure;
 386
 387                 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
 388                                  htonl(helper->expect_policy[i].timeout)))
 389                         goto nla_put_failure;
 390
 391                 nla_nest_end(skb, nest_parms2);
 392         }
 393         nla_nest_end(skb, nest_parms1);
 394         return 0;
 395
 396 nla_put_failure:
 397         return -1;
 398 }
 399
 400 static int
 401 nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
 402                         int event, struct nf_conntrack_helper *helper)
 403 {
 404         struct nlmsghdr *nlh;
 405         struct nfgenmsg *nfmsg;
 406         unsigned int flags = portid ? NLM_F_MULTI : 0;
 407         int status;
 408
 409         event |= NFNL_SUBSYS_CTHELPER << 8;
 410         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
 411         if (nlh == NULL)
 412                 goto nlmsg_failure;
 413
 414         nfmsg = nlmsg_data(nlh);
 415         nfmsg->nfgen_family = AF_UNSPEC;
 416         nfmsg->version = NFNETLINK_V0;
 417         nfmsg->res_id = 0;
 418
 419         if (nla_put_string(skb, NFCTH_NAME, helper->name))
 420                 goto nla_put_failure;
 421
 422         if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
 423                 goto nla_put_failure;
 424
 425         if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
 426                 goto nla_put_failure;
 427
 428         if (nfnl_cthelper_dump_policy(skb, helper) < 0)
 429                 goto nla_put_failure;
 430
 431         if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
 432                 goto nla_put_failure;
 433
 434         if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
 435                 status = NFCT_HELPER_STATUS_ENABLED;
 436         else
 437                 status = NFCT_HELPER_STATUS_DISABLED;
 438
 439         if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
 440                 goto nla_put_failure;
 441
 442         nlmsg_end(skb, nlh);
 443         return skb->len;
 444
 445 nlmsg_failure:
 446 nla_put_failure:
 447         nlmsg_cancel(skb, nlh);
 448         return -1;
 449 }
 450
 451 static int
 452 nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
 453 {
 454         struct nf_conntrack_helper *cur, *last;
 455         struct hlist_node *n;
 456
 457         rcu_read_lock();
 458         last = (struct nf_conntrack_helper *)cb->args[1];
 459         for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
 460 restart:
 461                 hlist_for_each_entry_rcu(cur, n,
 462                                 &nf_ct_helper_hash[cb->args[0]], hnode) {
 463
 464                         /* skip non-userspace conntrack helpers. */
 465                         if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 466                                 continue;
 467
 468                         if (cb->args[1]) {
 469                                 if (cur != last)
 470                                         continue;
 471                                 cb->args[1] = 0;
 472                         }
 473                         if (nfnl_cthelper_fill_info(skb,
 474                                             NETLINK_CB(cb->skb).portid,
 475                                             cb->nlh->nlmsg_seq,
 476                                             NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
 477                                             NFNL_MSG_CTHELPER_NEW, cur) < 0) {
 478                                 cb->args[1] = (unsigned long)cur;
 479                                 goto out;
 480                         }
 481                 }
 482         }
 483         if (cb->args[1]) {
 484                 cb->args[1] = 0;
 485                 goto restart;
 486         }
 487 out:
 488         rcu_read_unlock();
 489         return skb->len;
 490 }
 491
 492 static int
 493 nfnl_cthelper_get(struct sock *nfnl, struct sk_buff *skb,
 494                   const struct nlmsghdr *nlh, const struct nlattr * const tb[])
 495 {
 496         int ret = -ENOENT, i;
 497         struct nf_conntrack_helper *cur;
 498         struct hlist_node *n;
 499         struct sk_buff *skb2;
 500         char *helper_name = NULL;
 501         struct nf_conntrack_tuple tuple;
 502         bool tuple_set = false;
 503
 504         if (nlh->nlmsg_flags & NLM_F_DUMP) {
 505                 struct netlink_dump_control c = {
 506                         .dump = nfnl_cthelper_dump_table,
 507                 };
 508                 return netlink_dump_start(nfnl, skb, nlh, &c);
 509         }
 510
 511         if (tb[NFCTH_NAME])
 512                 helper_name = nla_data(tb[NFCTH_NAME]);
 513
 514         if (tb[NFCTH_TUPLE]) {
 515                 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
 516                 if (ret < 0)
 517                         return ret;
 518
 519                 tuple_set = true;
 520         }
 521
 522         for (i = 0; i < nf_ct_helper_hsize; i++) {
 523                 hlist_for_each_entry_rcu(cur, n, &nf_ct_helper_hash[i], hnode) {
 524
 525                         /* skip non-userspace conntrack helpers. */
 526                         if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 527                                 continue;
 528
 529                         if (helper_name && strncmp(cur->name, helper_name,
 530                                                 NF_CT_HELPER_NAME_LEN) != 0) {
 531                                 continue;
 532                         }
 533                         if (tuple_set &&
 534                             (tuple.src.l3num != cur->tuple.src.l3num ||
 535                              tuple.dst.protonum != cur->tuple.dst.protonum))
 536                                 continue;
 537
 538                         skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 539                         if (skb2 == NULL) {
 540                                 ret = -ENOMEM;
 541                                 break;
 542                         }
 543
 544                         ret = nfnl_cthelper_fill_info(skb2, NETLINK_CB(skb).portid,
 545                                                 nlh->nlmsg_seq,
 546                                                 NFNL_MSG_TYPE(nlh->nlmsg_type),
 547                                                 NFNL_MSG_CTHELPER_NEW, cur);
 548                         if (ret <= 0) {
 549                                 kfree_skb(skb2);
 550                                 break;
 551                         }
 552
 553                         ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
 554                                                 MSG_DONTWAIT);
 555                         if (ret > 0)
 556                                 ret = 0;
 557
 558                         /* this avoids a loop in nfnetlink. */
 559                         return ret == -EAGAIN ? -ENOBUFS : ret;
 560                 }
 561         }
 562         return ret;
 563 }
 564
 565 static int
 566 nfnl_cthelper_del(struct sock *nfnl, struct sk_buff *skb,
 567              const struct nlmsghdr *nlh, const struct nlattr * const tb[])
 568 {
 569         char *helper_name = NULL;
 570         struct nf_conntrack_helper *cur;
 571         struct hlist_node *n, *tmp;
 572         struct nf_conntrack_tuple tuple;
 573         bool tuple_set = false, found = false;
 574         int i, j = 0, ret;
 575
 576         if (tb[NFCTH_NAME])
 577                 helper_name = nla_data(tb[NFCTH_NAME]);
 578
 579         if (tb[NFCTH_TUPLE]) {
 580                 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
 581                 if (ret < 0)
 582                         return ret;
 583
 584                 tuple_set = true;
 585         }
 586
 587         for (i = 0; i < nf_ct_helper_hsize; i++) {
 588                 hlist_for_each_entry_safe(cur, n, tmp, &nf_ct_helper_hash[i],
 589                                                                 hnode) {
 590                         /* skip non-userspace conntrack helpers. */
 591                         if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 592                                 continue;
 593
 594                         j++;
 595
 596                         if (helper_name && strncmp(cur->name, helper_name,
 597                                                 NF_CT_HELPER_NAME_LEN) != 0) {
 598                                 continue;
 599                         }
 600                         if (tuple_set &&
 601                             (tuple.src.l3num != cur->tuple.src.l3num ||
 602                              tuple.dst.protonum != cur->tuple.dst.protonum))
 603                                 continue;
 604
 605                         found = true;
 606                         nf_conntrack_helper_unregister(cur);
 607                 }
 608         }
 609         /* Make sure we return success if we flush and there is no helpers */
 610         return (found || j == 0) ? 0 : -ENOENT;
 611 }
 612
 613 static const struct nla_policy nfnl_cthelper_policy[NFCTH_MAX+1] = {
 614         [NFCTH_NAME] = { .type = NLA_NUL_STRING,
 615                          .len = NF_CT_HELPER_NAME_LEN-1 },
 616         [NFCTH_QUEUE_NUM] = { .type = NLA_U32, },
 617 };
 618
 619 static const struct nfnl_callback nfnl_cthelper_cb[NFNL_MSG_CTHELPER_MAX] = {
 620         [NFNL_MSG_CTHELPER_NEW]         = { .call = nfnl_cthelper_new,
 621                                             .attr_count = NFCTH_MAX,
 622                                             .policy = nfnl_cthelper_policy },
 623         [NFNL_MSG_CTHELPER_GET]         = { .call = nfnl_cthelper_get,
 624                                             .attr_count = NFCTH_MAX,
 625                                             .policy = nfnl_cthelper_policy },
 626         [NFNL_MSG_CTHELPER_DEL]         = { .call = nfnl_cthelper_del,
 627                                             .attr_count = NFCTH_MAX,
 628                                             .policy = nfnl_cthelper_policy },
 629 };
 630
 631 static const struct nfnetlink_subsystem nfnl_cthelper_subsys = {
 632         .name                           = "cthelper",
 633         .subsys_id                      = NFNL_SUBSYS_CTHELPER,
 634         .cb_count                       = NFNL_MSG_CTHELPER_MAX,
 635         .cb                             = nfnl_cthelper_cb,
 636 };
 637
 638 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);
 639
 640 static int __init nfnl_cthelper_init(void)
 641 {
 642         int ret;
 643
 644         ret = nfnetlink_subsys_register(&nfnl_cthelper_subsys);
 645         if (ret < 0) {
 646                 pr_err("nfnl_cthelper: cannot register with nfnetlink.\n");
 647                 goto err_out;
 648         }
 649         return 0;
 650 err_out:
 651         return ret;
 652 }
 653
 654 static void __exit nfnl_cthelper_exit(void)
 655 {
 656         struct nf_conntrack_helper *cur;
 657         struct hlist_node *n, *tmp;
 658         int i;
 659
 660         nfnetlink_subsys_unregister(&nfnl_cthelper_subsys);
 661
 662         for (i=0; i<nf_ct_helper_hsize; i++) {
 663                 hlist_for_each_entry_safe(cur, n, tmp, &nf_ct_helper_hash[i],
 664                                                                         hnode) {
 665                         /* skip non-userspace conntrack helpers. */
 666                         if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 667                                 continue;
 668
 669                         nf_conntrack_helper_unregister(cur);
 670                 }
 671         }
 672 }
 673
 674 module_init(nfnl_cthelper_init);
 675 module_exit(nfnl_cthelper_exit);