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