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         /* Not all fields are initialized so first zero the tuple */
  78         memset(tuple, 0, sizeof(struct nf_conntrack_tuple));
  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         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         struct nlattr *tb[NFCTH_POLICY_MAX+1];
 128
 129         nla_parse_nested(tb, NFCTH_POLICY_MAX, attr, nfnl_cthelper_expect_pol);
 130
 131         if (!tb[NFCTH_POLICY_NAME] ||
 132             !tb[NFCTH_POLICY_EXPECT_MAX] ||
 133             !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
 134                 return -EINVAL;
 135
 136         strncpy(expect_policy->name,
 137                 nla_data(tb[NFCTH_POLICY_NAME]), NF_CT_HELPER_NAME_LEN);
 138         expect_policy->max_expected =
 139                 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
 140         expect_policy->timeout =
 141                 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
 142
 143         return 0;
 144 }
 145
 146 static const struct nla_policy
 147 nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = {
 148         [NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, },
 149 };
 150
 151 static int
 152 nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
 153                                   const struct nlattr *attr)
 154 {
 155         int i, ret;
 156         struct nf_conntrack_expect_policy *expect_policy;
 157         struct nlattr *tb[NFCTH_POLICY_SET_MAX+1];
 158
 159         nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
 160                                         nfnl_cthelper_expect_policy_set);
 161
 162         if (!tb[NFCTH_POLICY_SET_NUM])
 163                 return -EINVAL;
 164
 165         helper->expect_class_max =
 166                 ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
 167
 168         if (helper->expect_class_max != 0 &&
 169             helper->expect_class_max > NF_CT_MAX_EXPECT_CLASSES)
 170                 return -EOVERFLOW;
 171
 172         expect_policy = kzalloc(sizeof(struct nf_conntrack_expect_policy) *
 173                                 helper->expect_class_max, GFP_KERNEL);
 174         if (expect_policy == NULL)
 175                 return -ENOMEM;
 176
 177         for (i=0; i<helper->expect_class_max; i++) {
 178                 if (!tb[NFCTH_POLICY_SET+i])
 179                         goto err;
 180
 181                 ret = nfnl_cthelper_expect_policy(&expect_policy[i],
 182                                                   tb[NFCTH_POLICY_SET+i]);
 183                 if (ret < 0)
 184                         goto err;
 185         }
 186         helper->expect_policy = expect_policy;
 187         return 0;
 188 err:
 189         kfree(expect_policy);
 190         return -EINVAL;
 191 }
 192
 193 static int
 194 nfnl_cthelper_create(const struct nlattr * const tb[],
 195                      struct nf_conntrack_tuple *tuple)
 196 {
 197         struct nf_conntrack_helper *helper;
 198         int ret;
 199
 200         if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN])
 201                 return -EINVAL;
 202
 203         helper = kzalloc(sizeof(struct nf_conntrack_helper), GFP_KERNEL);
 204         if (helper == NULL)
 205                 return -ENOMEM;
 206
 207         ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]);
 208         if (ret < 0)
 209                 goto err;
 210
 211         strncpy(helper->name, nla_data(tb[NFCTH_NAME]), NF_CT_HELPER_NAME_LEN);
 212         helper->data_len = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
 213         helper->flags |= NF_CT_HELPER_F_USERSPACE;
 214         memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
 215
 216         helper->me = THIS_MODULE;
 217         helper->help = nfnl_userspace_cthelper;
 218         helper->from_nlattr = nfnl_cthelper_from_nlattr;
 219         helper->to_nlattr = nfnl_cthelper_to_nlattr;
 220
 221         /* Default to queue number zero, this can be updated at any time. */
 222         if (tb[NFCTH_QUEUE_NUM])
 223                 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
 224
 225         if (tb[NFCTH_STATUS]) {
 226                 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
 227
 228                 switch(status) {
 229                 case NFCT_HELPER_STATUS_ENABLED:
 230                         helper->flags |= NF_CT_HELPER_F_CONFIGURED;
 231                         break;
 232                 case NFCT_HELPER_STATUS_DISABLED:
 233                         helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
 234                         break;
 235                 }
 236         }
 237
 238         ret = nf_conntrack_helper_register(helper);
 239         if (ret < 0)
 240                 goto err;
 241
 242         return 0;
 243 err:
 244         kfree(helper);
 245         return ret;
 246 }
 247
 248 static int
 249 nfnl_cthelper_update(const struct nlattr * const tb[],
 250                      struct nf_conntrack_helper *helper)
 251 {
 252         int ret;
 253
 254         if (tb[NFCTH_PRIV_DATA_LEN])
 255                 return -EBUSY;
 256
 257         if (tb[NFCTH_POLICY]) {
 258                 ret = nfnl_cthelper_parse_expect_policy(helper,
 259                                                         tb[NFCTH_POLICY]);
 260                 if (ret < 0)
 261                         return ret;
 262         }
 263         if (tb[NFCTH_QUEUE_NUM])
 264                 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
 265
 266         if (tb[NFCTH_STATUS]) {
 267                 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
 268
 269                 switch(status) {
 270                 case NFCT_HELPER_STATUS_ENABLED:
 271                         helper->flags |= NF_CT_HELPER_F_CONFIGURED;
 272                         break;
 273                 case NFCT_HELPER_STATUS_DISABLED:
 274                         helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
 275                         break;
 276                 }
 277         }
 278         return 0;
 279 }
 280
 281 static int
 282 nfnl_cthelper_new(struct sock *nfnl, struct sk_buff *skb,
 283                   const struct nlmsghdr *nlh, const struct nlattr * const tb[])
 284 {
 285         const char *helper_name;
 286         struct nf_conntrack_helper *cur, *helper = NULL;
 287         struct nf_conntrack_tuple tuple;
 288         int ret = 0, i;
 289
 290         if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE])
 291                 return -EINVAL;
 292
 293         helper_name = nla_data(tb[NFCTH_NAME]);
 294
 295         ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
 296         if (ret < 0)
 297                 return ret;
 298
 299         rcu_read_lock();
 300         for (i = 0; i < nf_ct_helper_hsize && !helper; i++) {
 301                 hlist_for_each_entry_rcu(cur, &nf_ct_helper_hash[i], hnode) {
 302
 303                         /* skip non-userspace conntrack helpers. */
 304                         if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 305                                 continue;
 306
 307                         if (strncmp(cur->name, helper_name,
 308                                         NF_CT_HELPER_NAME_LEN) != 0)
 309                                 continue;
 310
 311                         if ((tuple.src.l3num != cur->tuple.src.l3num ||
 312                              tuple.dst.protonum != cur->tuple.dst.protonum))
 313                                 continue;
 314
 315                         if (nlh->nlmsg_flags & NLM_F_EXCL) {
 316                                 ret = -EEXIST;
 317                                 goto err;
 318                         }
 319                         helper = cur;
 320                         break;
 321                 }
 322         }
 323         rcu_read_unlock();
 324
 325         if (helper == NULL)
 326                 ret = nfnl_cthelper_create(tb, &tuple);
 327         else
 328                 ret = nfnl_cthelper_update(tb, helper);
 329
 330         return ret;
 331 err:
 332         rcu_read_unlock();
 333         return ret;
 334 }
 335
 336 static int
 337 nfnl_cthelper_dump_tuple(struct sk_buff *skb,
 338                          struct nf_conntrack_helper *helper)
 339 {
 340         struct nlattr *nest_parms;
 341
 342         nest_parms = nla_nest_start(skb, NFCTH_TUPLE | NLA_F_NESTED);
 343         if (nest_parms == NULL)
 344                 goto nla_put_failure;
 345
 346         if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
 347                          htons(helper->tuple.src.l3num)))
 348                 goto nla_put_failure;
 349
 350         if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
 351                 goto nla_put_failure;
 352
 353         nla_nest_end(skb, nest_parms);
 354         return 0;
 355
 356 nla_put_failure:
 357         return -1;
 358 }
 359
 360 static int
 361 nfnl_cthelper_dump_policy(struct sk_buff *skb,
 362                         struct nf_conntrack_helper *helper)
 363 {
 364         int i;
 365         struct nlattr *nest_parms1, *nest_parms2;
 366
 367         nest_parms1 = nla_nest_start(skb, NFCTH_POLICY | NLA_F_NESTED);
 368         if (nest_parms1 == NULL)
 369                 goto nla_put_failure;
 370
 371         if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
 372                          htonl(helper->expect_class_max)))
 373                 goto nla_put_failure;
 374
 375         for (i=0; i<helper->expect_class_max; i++) {
 376                 nest_parms2 = nla_nest_start(skb,
 377                                 (NFCTH_POLICY_SET+i) | NLA_F_NESTED);
 378                 if (nest_parms2 == NULL)
 379                         goto nla_put_failure;
 380
 381                 if (nla_put_string(skb, NFCTH_POLICY_NAME,
 382                                    helper->expect_policy[i].name))
 383                         goto nla_put_failure;
 384
 385                 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
 386                                  htonl(helper->expect_policy[i].max_expected)))
 387                         goto nla_put_failure;
 388
 389                 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
 390                                  htonl(helper->expect_policy[i].timeout)))
 391                         goto nla_put_failure;
 392
 393                 nla_nest_end(skb, nest_parms2);
 394         }
 395         nla_nest_end(skb, nest_parms1);
 396         return 0;
 397
 398 nla_put_failure:
 399         return -1;
 400 }
 401
 402 static int
 403 nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
 404                         int event, struct nf_conntrack_helper *helper)
 405 {
 406         struct nlmsghdr *nlh;
 407         struct nfgenmsg *nfmsg;
 408         unsigned int flags = portid ? NLM_F_MULTI : 0;
 409         int status;
 410
 411         event |= NFNL_SUBSYS_CTHELPER << 8;
 412         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
 413         if (nlh == NULL)
 414                 goto nlmsg_failure;
 415
 416         nfmsg = nlmsg_data(nlh);
 417         nfmsg->nfgen_family = AF_UNSPEC;
 418         nfmsg->version = NFNETLINK_V0;
 419         nfmsg->res_id = 0;
 420
 421         if (nla_put_string(skb, NFCTH_NAME, helper->name))
 422                 goto nla_put_failure;
 423
 424         if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
 425                 goto nla_put_failure;
 426
 427         if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
 428                 goto nla_put_failure;
 429
 430         if (nfnl_cthelper_dump_policy(skb, helper) < 0)
 431                 goto nla_put_failure;
 432
 433         if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
 434                 goto nla_put_failure;
 435
 436         if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
 437                 status = NFCT_HELPER_STATUS_ENABLED;
 438         else
 439                 status = NFCT_HELPER_STATUS_DISABLED;
 440
 441         if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
 442                 goto nla_put_failure;
 443
 444         nlmsg_end(skb, nlh);
 445         return skb->len;
 446
 447 nlmsg_failure:
 448 nla_put_failure:
 449         nlmsg_cancel(skb, nlh);
 450         return -1;
 451 }
 452
 453 static int
 454 nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
 455 {
 456         struct nf_conntrack_helper *cur, *last;
 457
 458         rcu_read_lock();
 459         last = (struct nf_conntrack_helper *)cb->args[1];
 460         for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
 461 restart:
 462                 hlist_for_each_entry_rcu(cur,
 463                                 &nf_ct_helper_hash[cb->args[0]], hnode) {
 464
 465                         /* skip non-userspace conntrack helpers. */
 466                         if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 467                                 continue;
 468
 469                         if (cb->args[1]) {
 470                                 if (cur != last)
 471                                         continue;
 472                                 cb->args[1] = 0;
 473                         }
 474                         if (nfnl_cthelper_fill_info(skb,
 475                                             NETLINK_CB(cb->skb).portid,
 476                                             cb->nlh->nlmsg_seq,
 477                                             NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
 478                                             NFNL_MSG_CTHELPER_NEW, cur) < 0) {
 479                                 cb->args[1] = (unsigned long)cur;
 480                                 goto out;
 481                         }
 482                 }
 483         }
 484         if (cb->args[1]) {
 485                 cb->args[1] = 0;
 486                 goto restart;
 487         }
 488 out:
 489         rcu_read_unlock();
 490         return skb->len;
 491 }
 492
 493 static int
 494 nfnl_cthelper_get(struct sock *nfnl, struct sk_buff *skb,
 495                   const struct nlmsghdr *nlh, const struct nlattr * const tb[])
 496 {
 497         int ret = -ENOENT, i;
 498         struct nf_conntrack_helper *cur;
 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, &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 *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, 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 *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, 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);