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         int err;
  71         struct nlattr *tb[NFCTH_TUPLE_MAX+1];
  72
  73         err = nla_parse_nested(tb, NFCTH_TUPLE_MAX, attr, nfnl_cthelper_tuple_pol);
  74         if (err < 0)
  75                 return err;
  76
  77         if (!tb[NFCTH_TUPLE_L3PROTONUM] || !tb[NFCTH_TUPLE_L4PROTONUM])
  78                 return -EINVAL;
  79
  80         tuple->src.l3num = ntohs(nla_get_be16(tb[NFCTH_TUPLE_L3PROTONUM]));
  81         tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]);
  82
  83         return 0;
  84 }
  85
  86 static int
  87 nfnl_cthelper_from_nlattr(struct nlattr *attr, struct nf_conn *ct)
  88 {
  89         const struct nf_conn_help *help = nfct_help(ct);
  90
  91         if (attr == NULL)
  92                 return -EINVAL;
  93
  94         if (help->helper->data_len == 0)
  95                 return -EINVAL;
  96
  97         memcpy(&help->data, nla_data(attr), help->helper->data_len);
  98         return 0;
  99 }
 100
 101 static int
 102 nfnl_cthelper_to_nlattr(struct sk_buff *skb, const struct nf_conn *ct)
 103 {
 104         const struct nf_conn_help *help = nfct_help(ct);
 105
 106         if (help->helper->data_len &&
 107             nla_put(skb, CTA_HELP_INFO, help->helper->data_len, &help->data))
 108                 goto nla_put_failure;
 109
 110         return 0;
 111
 112 nla_put_failure:
 113         return -ENOSPC;
 114 }
 115
 116 static const struct nla_policy nfnl_cthelper_expect_pol[NFCTH_POLICY_MAX+1] = {
 117         [NFCTH_POLICY_NAME] = { .type = NLA_NUL_STRING,
 118                                 .len = NF_CT_HELPER_NAME_LEN-1 },
 119         [NFCTH_POLICY_EXPECT_MAX] = { .type = NLA_U32, },
 120         [NFCTH_POLICY_EXPECT_TIMEOUT] = { .type = NLA_U32, },
 121 };
 122
 123 static int
 124 nfnl_cthelper_expect_policy(struct nf_conntrack_expect_policy *expect_policy,
 125                             const struct nlattr *attr)
 126 {
 127         int err;
 128         struct nlattr *tb[NFCTH_POLICY_MAX+1];
 129
 130         err = nla_parse_nested(tb, NFCTH_POLICY_MAX, attr, nfnl_cthelper_expect_pol);
 131         if (err < 0)
 132                 return err;
 133
 134         if (!tb[NFCTH_POLICY_NAME] ||
 135             !tb[NFCTH_POLICY_EXPECT_MAX] ||
 136             !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
 137                 return -EINVAL;
 138
 139         strncpy(expect_policy->name,
 140                 nla_data(tb[NFCTH_POLICY_NAME]), NF_CT_HELPER_NAME_LEN);
 141         expect_policy->max_expected =
 142                 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
 143         expect_policy->timeout =
 144                 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
 145
 146         return 0;
 147 }
 148
 149 static const struct nla_policy
 150 nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = {
 151         [NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, },
 152 };
 153
 154 static int
 155 nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
 156                                   const struct nlattr *attr)
 157 {
 158         int i, ret;
 159         struct nf_conntrack_expect_policy *expect_policy;
 160         struct nlattr *tb[NFCTH_POLICY_SET_MAX+1];
 161
 162         ret = nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
 163                                nfnl_cthelper_expect_policy_set);
 164         if (ret < 0)
 165                 return ret;
 166
 167         if (!tb[NFCTH_POLICY_SET_NUM])
 168                 return -EINVAL;
 169
 170         helper->expect_class_max =
 171                 ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
 172
 173         if (helper->expect_class_max != 0 &&
 174             helper->expect_class_max > NF_CT_MAX_EXPECT_CLASSES)
 175                 return -EOVERFLOW;
 176
 177         expect_policy = kzalloc(sizeof(struct nf_conntrack_expect_policy) *
 178                                 helper->expect_class_max, GFP_KERNEL);
 179         if (expect_policy == NULL)
 180                 return -ENOMEM;
 181
 182         for (i=0; i<helper->expect_class_max; i++) {
 183                 if (!tb[NFCTH_POLICY_SET+i])
 184                         goto err;
 185
 186                 ret = nfnl_cthelper_expect_policy(&expect_policy[i],
 187                                                   tb[NFCTH_POLICY_SET+i]);
 188                 if (ret < 0)
 189                         goto err;
 190         }
 191         helper->expect_policy = expect_policy;
 192         return 0;
 193 err:
 194         kfree(expect_policy);
 195         return -EINVAL;
 196 }
 197
 198 static int
 199 nfnl_cthelper_create(const struct nlattr * const tb[],
 200                      struct nf_conntrack_tuple *tuple)
 201 {
 202         struct nf_conntrack_helper *helper;
 203         int ret;
 204
 205         if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN])
 206                 return -EINVAL;
 207
 208         helper = kzalloc(sizeof(struct nf_conntrack_helper), GFP_KERNEL);
 209         if (helper == NULL)
 210                 return -ENOMEM;
 211
 212         ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]);
 213         if (ret < 0)
 214                 goto err;
 215
 216         strncpy(helper->name, nla_data(tb[NFCTH_NAME]), NF_CT_HELPER_NAME_LEN);
 217         helper->data_len = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
 218         helper->flags |= NF_CT_HELPER_F_USERSPACE;
 219         memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
 220
 221         helper->me = THIS_MODULE;
 222         helper->help = nfnl_userspace_cthelper;
 223         helper->from_nlattr = nfnl_cthelper_from_nlattr;
 224         helper->to_nlattr = nfnl_cthelper_to_nlattr;
 225
 226         /* Default to queue number zero, this can be updated at any time. */
 227         if (tb[NFCTH_QUEUE_NUM])
 228                 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
 229
 230         if (tb[NFCTH_STATUS]) {
 231                 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
 232
 233                 switch(status) {
 234                 case NFCT_HELPER_STATUS_ENABLED:
 235                         helper->flags |= NF_CT_HELPER_F_CONFIGURED;
 236                         break;
 237                 case NFCT_HELPER_STATUS_DISABLED:
 238                         helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
 239                         break;
 240                 }
 241         }
 242
 243         ret = nf_conntrack_helper_register(helper);
 244         if (ret < 0)
 245                 goto err;
 246
 247         return 0;
 248 err:
 249         kfree(helper);
 250         return ret;
 251 }
 252
 253 static int
 254 nfnl_cthelper_update(const struct nlattr * const tb[],
 255                      struct nf_conntrack_helper *helper)
 256 {
 257         int ret;
 258
 259         if (tb[NFCTH_PRIV_DATA_LEN])
 260                 return -EBUSY;
 261
 262         if (tb[NFCTH_POLICY]) {
 263                 ret = nfnl_cthelper_parse_expect_policy(helper,
 264                                                         tb[NFCTH_POLICY]);
 265                 if (ret < 0)
 266                         return ret;
 267         }
 268         if (tb[NFCTH_QUEUE_NUM])
 269                 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
 270
 271         if (tb[NFCTH_STATUS]) {
 272                 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
 273
 274                 switch(status) {
 275                 case NFCT_HELPER_STATUS_ENABLED:
 276                         helper->flags |= NF_CT_HELPER_F_CONFIGURED;
 277                         break;
 278                 case NFCT_HELPER_STATUS_DISABLED:
 279                         helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
 280                         break;
 281                 }
 282         }
 283         return 0;
 284 }
 285
 286 static int
 287 nfnl_cthelper_new(struct sock *nfnl, struct sk_buff *skb,
 288                   const struct nlmsghdr *nlh, const struct nlattr * const tb[])
 289 {
 290         const char *helper_name;
 291         struct nf_conntrack_helper *cur, *helper = NULL;
 292         struct nf_conntrack_tuple tuple;
 293         int ret = 0, i;
 294
 295         if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE])
 296                 return -EINVAL;
 297
 298         helper_name = nla_data(tb[NFCTH_NAME]);
 299
 300         ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
 301         if (ret < 0)
 302                 return ret;
 303
 304         rcu_read_lock();
 305         for (i = 0; i < nf_ct_helper_hsize && !helper; i++) {
 306                 hlist_for_each_entry_rcu(cur, &nf_ct_helper_hash[i], hnode) {
 307
 308                         /* skip non-userspace conntrack helpers. */
 309                         if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 310                                 continue;
 311
 312                         if (strncmp(cur->name, helper_name,
 313                                         NF_CT_HELPER_NAME_LEN) != 0)
 314                                 continue;
 315
 316                         if ((tuple.src.l3num != cur->tuple.src.l3num ||
 317                              tuple.dst.protonum != cur->tuple.dst.protonum))
 318                                 continue;
 319
 320                         if (nlh->nlmsg_flags & NLM_F_EXCL) {
 321                                 ret = -EEXIST;
 322                                 goto err;
 323                         }
 324                         helper = cur;
 325                         break;
 326                 }
 327         }
 328         rcu_read_unlock();
 329
 330         if (helper == NULL)
 331                 ret = nfnl_cthelper_create(tb, &tuple);
 332         else
 333                 ret = nfnl_cthelper_update(tb, helper);
 334
 335         return ret;
 336 err:
 337         rcu_read_unlock();
 338         return ret;
 339 }
 340
 341 static int
 342 nfnl_cthelper_dump_tuple(struct sk_buff *skb,
 343                          struct nf_conntrack_helper *helper)
 344 {
 345         struct nlattr *nest_parms;
 346
 347         nest_parms = nla_nest_start(skb, NFCTH_TUPLE | NLA_F_NESTED);
 348         if (nest_parms == NULL)
 349                 goto nla_put_failure;
 350
 351         if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
 352                          htons(helper->tuple.src.l3num)))
 353                 goto nla_put_failure;
 354
 355         if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
 356                 goto nla_put_failure;
 357
 358         nla_nest_end(skb, nest_parms);
 359         return 0;
 360
 361 nla_put_failure:
 362         return -1;
 363 }
 364
 365 static int
 366 nfnl_cthelper_dump_policy(struct sk_buff *skb,
 367                         struct nf_conntrack_helper *helper)
 368 {
 369         int i;
 370         struct nlattr *nest_parms1, *nest_parms2;
 371
 372         nest_parms1 = nla_nest_start(skb, NFCTH_POLICY | NLA_F_NESTED);
 373         if (nest_parms1 == NULL)
 374                 goto nla_put_failure;
 375
 376         if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
 377                          htonl(helper->expect_class_max)))
 378                 goto nla_put_failure;
 379
 380         for (i=0; i<helper->expect_class_max; i++) {
 381                 nest_parms2 = nla_nest_start(skb,
 382                                 (NFCTH_POLICY_SET+i) | NLA_F_NESTED);
 383                 if (nest_parms2 == NULL)
 384                         goto nla_put_failure;
 385
 386                 if (nla_put_string(skb, NFCTH_POLICY_NAME,
 387                                    helper->expect_policy[i].name))
 388                         goto nla_put_failure;
 389
 390                 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
 391                                  htonl(helper->expect_policy[i].max_expected)))
 392                         goto nla_put_failure;
 393
 394                 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
 395                                  htonl(helper->expect_policy[i].timeout)))
 396                         goto nla_put_failure;
 397
 398                 nla_nest_end(skb, nest_parms2);
 399         }
 400         nla_nest_end(skb, nest_parms1);
 401         return 0;
 402
 403 nla_put_failure:
 404         return -1;
 405 }
 406
 407 static int
 408 nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
 409                         int event, struct nf_conntrack_helper *helper)
 410 {
 411         struct nlmsghdr *nlh;
 412         struct nfgenmsg *nfmsg;
 413         unsigned int flags = portid ? NLM_F_MULTI : 0;
 414         int status;
 415
 416         event |= NFNL_SUBSYS_CTHELPER << 8;
 417         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
 418         if (nlh == NULL)
 419                 goto nlmsg_failure;
 420
 421         nfmsg = nlmsg_data(nlh);
 422         nfmsg->nfgen_family = AF_UNSPEC;
 423         nfmsg->version = NFNETLINK_V0;
 424         nfmsg->res_id = 0;
 425
 426         if (nla_put_string(skb, NFCTH_NAME, helper->name))
 427                 goto nla_put_failure;
 428
 429         if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
 430                 goto nla_put_failure;
 431
 432         if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
 433                 goto nla_put_failure;
 434
 435         if (nfnl_cthelper_dump_policy(skb, helper) < 0)
 436                 goto nla_put_failure;
 437
 438         if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
 439                 goto nla_put_failure;
 440
 441         if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
 442                 status = NFCT_HELPER_STATUS_ENABLED;
 443         else
 444                 status = NFCT_HELPER_STATUS_DISABLED;
 445
 446         if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
 447                 goto nla_put_failure;
 448
 449         nlmsg_end(skb, nlh);
 450         return skb->len;
 451
 452 nlmsg_failure:
 453 nla_put_failure:
 454         nlmsg_cancel(skb, nlh);
 455         return -1;
 456 }
 457
 458 static int
 459 nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
 460 {
 461         struct nf_conntrack_helper *cur, *last;
 462
 463         rcu_read_lock();
 464         last = (struct nf_conntrack_helper *)cb->args[1];
 465         for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
 466 restart:
 467                 hlist_for_each_entry_rcu(cur,
 468                                 &nf_ct_helper_hash[cb->args[0]], hnode) {
 469
 470                         /* skip non-userspace conntrack helpers. */
 471                         if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 472                                 continue;
 473
 474                         if (cb->args[1]) {
 475                                 if (cur != last)
 476                                         continue;
 477                                 cb->args[1] = 0;
 478                         }
 479                         if (nfnl_cthelper_fill_info(skb,
 480                                             NETLINK_CB(cb->skb).portid,
 481                                             cb->nlh->nlmsg_seq,
 482                                             NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
 483                                             NFNL_MSG_CTHELPER_NEW, cur) < 0) {
 484                                 cb->args[1] = (unsigned long)cur;
 485                                 goto out;
 486                         }
 487                 }
 488         }
 489         if (cb->args[1]) {
 490                 cb->args[1] = 0;
 491                 goto restart;
 492         }
 493 out:
 494         rcu_read_unlock();
 495         return skb->len;
 496 }
 497
 498 static int
 499 nfnl_cthelper_get(struct sock *nfnl, struct sk_buff *skb,
 500                   const struct nlmsghdr *nlh, const struct nlattr * const tb[])
 501 {
 502         int ret = -ENOENT, i;
 503         struct nf_conntrack_helper *cur;
 504         struct sk_buff *skb2;
 505         char *helper_name = NULL;
 506         struct nf_conntrack_tuple tuple;
 507         bool tuple_set = false;
 508
 509         if (nlh->nlmsg_flags & NLM_F_DUMP) {
 510                 struct netlink_dump_control c = {
 511                         .dump = nfnl_cthelper_dump_table,
 512                 };
 513                 return netlink_dump_start(nfnl, skb, nlh, &c);
 514         }
 515
 516         if (tb[NFCTH_NAME])
 517                 helper_name = nla_data(tb[NFCTH_NAME]);
 518
 519         if (tb[NFCTH_TUPLE]) {
 520                 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
 521                 if (ret < 0)
 522                         return ret;
 523
 524                 tuple_set = true;
 525         }
 526
 527         for (i = 0; i < nf_ct_helper_hsize; i++) {
 528                 hlist_for_each_entry_rcu(cur, &nf_ct_helper_hash[i], hnode) {
 529
 530                         /* skip non-userspace conntrack helpers. */
 531                         if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 532                                 continue;
 533
 534                         if (helper_name && strncmp(cur->name, helper_name,
 535                                                 NF_CT_HELPER_NAME_LEN) != 0) {
 536                                 continue;
 537                         }
 538                         if (tuple_set &&
 539                             (tuple.src.l3num != cur->tuple.src.l3num ||
 540                              tuple.dst.protonum != cur->tuple.dst.protonum))
 541                                 continue;
 542
 543                         skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 544                         if (skb2 == NULL) {
 545                                 ret = -ENOMEM;
 546                                 break;
 547                         }
 548
 549                         ret = nfnl_cthelper_fill_info(skb2, NETLINK_CB(skb).portid,
 550                                                 nlh->nlmsg_seq,
 551                                                 NFNL_MSG_TYPE(nlh->nlmsg_type),
 552                                                 NFNL_MSG_CTHELPER_NEW, cur);
 553                         if (ret <= 0) {
 554                                 kfree_skb(skb2);
 555                                 break;
 556                         }
 557
 558                         ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
 559                                                 MSG_DONTWAIT);
 560                         if (ret > 0)
 561                                 ret = 0;
 562
 563                         /* this avoids a loop in nfnetlink. */
 564                         return ret == -EAGAIN ? -ENOBUFS : ret;
 565                 }
 566         }
 567         return ret;
 568 }
 569
 570 static int
 571 nfnl_cthelper_del(struct sock *nfnl, struct sk_buff *skb,
 572              const struct nlmsghdr *nlh, const struct nlattr * const tb[])
 573 {
 574         char *helper_name = NULL;
 575         struct nf_conntrack_helper *cur;
 576         struct hlist_node *tmp;
 577         struct nf_conntrack_tuple tuple;
 578         bool tuple_set = false, found = false;
 579         int i, j = 0, ret;
 580
 581         if (tb[NFCTH_NAME])
 582                 helper_name = nla_data(tb[NFCTH_NAME]);
 583
 584         if (tb[NFCTH_TUPLE]) {
 585                 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
 586                 if (ret < 0)
 587                         return ret;
 588
 589                 tuple_set = true;
 590         }
 591
 592         for (i = 0; i < nf_ct_helper_hsize; i++) {
 593                 hlist_for_each_entry_safe(cur, tmp, &nf_ct_helper_hash[i],
 594                                                                 hnode) {
 595                         /* skip non-userspace conntrack helpers. */
 596                         if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 597                                 continue;
 598
 599                         j++;
 600
 601                         if (helper_name && strncmp(cur->name, helper_name,
 602                                                 NF_CT_HELPER_NAME_LEN) != 0) {
 603                                 continue;
 604                         }
 605                         if (tuple_set &&
 606                             (tuple.src.l3num != cur->tuple.src.l3num ||
 607                              tuple.dst.protonum != cur->tuple.dst.protonum))
 608                                 continue;
 609
 610                         found = true;
 611                         nf_conntrack_helper_unregister(cur);
 612                 }
 613         }
 614         /* Make sure we return success if we flush and there is no helpers */
 615         return (found || j == 0) ? 0 : -ENOENT;
 616 }
 617
 618 static const struct nla_policy nfnl_cthelper_policy[NFCTH_MAX+1] = {
 619         [NFCTH_NAME] = { .type = NLA_NUL_STRING,
 620                          .len = NF_CT_HELPER_NAME_LEN-1 },
 621         [NFCTH_QUEUE_NUM] = { .type = NLA_U32, },
 622 };
 623
 624 static const struct nfnl_callback nfnl_cthelper_cb[NFNL_MSG_CTHELPER_MAX] = {
 625         [NFNL_MSG_CTHELPER_NEW]         = { .call = nfnl_cthelper_new,
 626                                             .attr_count = NFCTH_MAX,
 627                                             .policy = nfnl_cthelper_policy },
 628         [NFNL_MSG_CTHELPER_GET]         = { .call = nfnl_cthelper_get,
 629                                             .attr_count = NFCTH_MAX,
 630                                             .policy = nfnl_cthelper_policy },
 631         [NFNL_MSG_CTHELPER_DEL]         = { .call = nfnl_cthelper_del,
 632                                             .attr_count = NFCTH_MAX,
 633                                             .policy = nfnl_cthelper_policy },
 634 };
 635
 636 static const struct nfnetlink_subsystem nfnl_cthelper_subsys = {
 637         .name                           = "cthelper",
 638         .subsys_id                      = NFNL_SUBSYS_CTHELPER,
 639         .cb_count                       = NFNL_MSG_CTHELPER_MAX,
 640         .cb                             = nfnl_cthelper_cb,
 641 };
 642
 643 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);
 644
 645 static int __init nfnl_cthelper_init(void)
 646 {
 647         int ret;
 648
 649         ret = nfnetlink_subsys_register(&nfnl_cthelper_subsys);
 650         if (ret < 0) {
 651                 pr_err("nfnl_cthelper: cannot register with nfnetlink.\n");
 652                 goto err_out;
 653         }
 654         return 0;
 655 err_out:
 656         return ret;
 657 }
 658
 659 static void __exit nfnl_cthelper_exit(void)
 660 {
 661         struct nf_conntrack_helper *cur;
 662         struct hlist_node *tmp;
 663         int i;
 664
 665         nfnetlink_subsys_unregister(&nfnl_cthelper_subsys);
 666
 667         for (i=0; i<nf_ct_helper_hsize; i++) {
 668                 hlist_for_each_entry_safe(cur, tmp, &nf_ct_helper_hash[i],
 669                                                                         hnode) {
 670                         /* skip non-userspace conntrack helpers. */
 671                         if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 672                                 continue;
 673
 674                         nf_conntrack_helper_unregister(cur);
 675                 }
 676         }
 677 }
 678
 679 module_init(nfnl_cthelper_init);
 680 module_exit(nfnl_cthelper_exit);