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         /* Not all fields are initialized so first zero the tuple */
  81         memset(tuple, 0, sizeof(struct nf_conntrack_tuple));
  82
  83         tuple->src.l3num = ntohs(nla_get_be16(tb[NFCTH_TUPLE_L3PROTONUM]));
  84         tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]);
  85
  86         return 0;
  87 }
  88
  89 static int
  90 nfnl_cthelper_from_nlattr(struct nlattr *attr, struct nf_conn *ct)
  91 {
  92         struct nf_conn_help *help = nfct_help(ct);
  93
  94         if (attr == NULL)
  95                 return -EINVAL;
  96
  97         if (help->helper->data_len == 0)
  98                 return -EINVAL;
  99
 100         memcpy(help->data, nla_data(attr), help->helper->data_len);
 101         return 0;
 102 }
 103
 104 static int
 105 nfnl_cthelper_to_nlattr(struct sk_buff *skb, const struct nf_conn *ct)
 106 {
 107         const struct nf_conn_help *help = nfct_help(ct);
 108
 109         if (help->helper->data_len &&
 110             nla_put(skb, CTA_HELP_INFO, help->helper->data_len, &help->data))
 111                 goto nla_put_failure;
 112
 113         return 0;
 114
 115 nla_put_failure:
 116         return -ENOSPC;
 117 }
 118
 119 static const struct nla_policy nfnl_cthelper_expect_pol[NFCTH_POLICY_MAX+1] = {
 120         [NFCTH_POLICY_NAME] = { .type = NLA_NUL_STRING,
 121                                 .len = NF_CT_HELPER_NAME_LEN-1 },
 122         [NFCTH_POLICY_EXPECT_MAX] = { .type = NLA_U32, },
 123         [NFCTH_POLICY_EXPECT_TIMEOUT] = { .type = NLA_U32, },
 124 };
 125
 126 static int
 127 nfnl_cthelper_expect_policy(struct nf_conntrack_expect_policy *expect_policy,
 128                             const struct nlattr *attr)
 129 {
 130         int err;
 131         struct nlattr *tb[NFCTH_POLICY_MAX+1];
 132
 133         err = nla_parse_nested(tb, NFCTH_POLICY_MAX, attr, nfnl_cthelper_expect_pol);
 134         if (err < 0)
 135                 return err;
 136
 137         if (!tb[NFCTH_POLICY_NAME] ||
 138             !tb[NFCTH_POLICY_EXPECT_MAX] ||
 139             !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
 140                 return -EINVAL;
 141
 142         strncpy(expect_policy->name,
 143                 nla_data(tb[NFCTH_POLICY_NAME]), NF_CT_HELPER_NAME_LEN);
 144         expect_policy->max_expected =
 145                 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
 146         expect_policy->timeout =
 147                 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
 148
 149         return 0;
 150 }
 151
 152 static const struct nla_policy
 153 nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = {
 154         [NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, },
 155 };
 156
 157 static int
 158 nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
 159                                   const struct nlattr *attr)
 160 {
 161         int i, ret;
 162         struct nf_conntrack_expect_policy *expect_policy;
 163         struct nlattr *tb[NFCTH_POLICY_SET_MAX+1];
 164
 165         ret = nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
 166                                nfnl_cthelper_expect_policy_set);
 167         if (ret < 0)
 168                 return ret;
 169
 170         if (!tb[NFCTH_POLICY_SET_NUM])
 171                 return -EINVAL;
 172
 173         helper->expect_class_max =
 174                 ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
 175
 176         if (helper->expect_class_max != 0 &&
 177             helper->expect_class_max > NF_CT_MAX_EXPECT_CLASSES)
 178                 return -EOVERFLOW;
 179
 180         expect_policy = kzalloc(sizeof(struct nf_conntrack_expect_policy) *
 181                                 helper->expect_class_max, GFP_KERNEL);
 182         if (expect_policy == NULL)
 183                 return -ENOMEM;
 184
 185         for (i=0; i<helper->expect_class_max; i++) {
 186                 if (!tb[NFCTH_POLICY_SET+i])
 187                         goto err;
 188
 189                 ret = nfnl_cthelper_expect_policy(&expect_policy[i],
 190                                                   tb[NFCTH_POLICY_SET+i]);
 191                 if (ret < 0)
 192                         goto err;
 193         }
 194         helper->expect_policy = expect_policy;
 195         return 0;
 196 err:
 197         kfree(expect_policy);
 198         return -EINVAL;
 199 }
 200
 201 static int
 202 nfnl_cthelper_create(const struct nlattr * const tb[],
 203                      struct nf_conntrack_tuple *tuple)
 204 {
 205         struct nf_conntrack_helper *helper;
 206         int ret;
 207
 208         if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN])
 209                 return -EINVAL;
 210
 211         helper = kzalloc(sizeof(struct nf_conntrack_helper), GFP_KERNEL);
 212         if (helper == NULL)
 213                 return -ENOMEM;
 214
 215         ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]);
 216         if (ret < 0)
 217                 goto err;
 218
 219         strncpy(helper->name, nla_data(tb[NFCTH_NAME]), NF_CT_HELPER_NAME_LEN);
 220         helper->data_len = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
 221         helper->flags |= NF_CT_HELPER_F_USERSPACE;
 222         memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
 223
 224         helper->me = THIS_MODULE;
 225         helper->help = nfnl_userspace_cthelper;
 226         helper->from_nlattr = nfnl_cthelper_from_nlattr;
 227         helper->to_nlattr = nfnl_cthelper_to_nlattr;
 228
 229         /* Default to queue number zero, this can be updated at any time. */
 230         if (tb[NFCTH_QUEUE_NUM])
 231                 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
 232
 233         if (tb[NFCTH_STATUS]) {
 234                 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
 235
 236                 switch(status) {
 237                 case NFCT_HELPER_STATUS_ENABLED:
 238                         helper->flags |= NF_CT_HELPER_F_CONFIGURED;
 239                         break;
 240                 case NFCT_HELPER_STATUS_DISABLED:
 241                         helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
 242                         break;
 243                 }
 244         }
 245
 246         ret = nf_conntrack_helper_register(helper);
 247         if (ret < 0)
 248                 goto err;
 249
 250         return 0;
 251 err:
 252         kfree(helper);
 253         return ret;
 254 }
 255
 256 static int
 257 nfnl_cthelper_update(const struct nlattr * const tb[],
 258                      struct nf_conntrack_helper *helper)
 259 {
 260         int ret;
 261
 262         if (tb[NFCTH_PRIV_DATA_LEN])
 263                 return -EBUSY;
 264
 265         if (tb[NFCTH_POLICY]) {
 266                 ret = nfnl_cthelper_parse_expect_policy(helper,
 267                                                         tb[NFCTH_POLICY]);
 268                 if (ret < 0)
 269                         return ret;
 270         }
 271         if (tb[NFCTH_QUEUE_NUM])
 272                 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
 273
 274         if (tb[NFCTH_STATUS]) {
 275                 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
 276
 277                 switch(status) {
 278                 case NFCT_HELPER_STATUS_ENABLED:
 279                         helper->flags |= NF_CT_HELPER_F_CONFIGURED;
 280                         break;
 281                 case NFCT_HELPER_STATUS_DISABLED:
 282                         helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
 283                         break;
 284                 }
 285         }
 286         return 0;
 287 }
 288
 289 static int
 290 nfnl_cthelper_new(struct sock *nfnl, struct sk_buff *skb,
 291                   const struct nlmsghdr *nlh, const struct nlattr * const tb[])
 292 {
 293         const char *helper_name;
 294         struct nf_conntrack_helper *cur, *helper = NULL;
 295         struct nf_conntrack_tuple tuple;
 296         int ret = 0, i;
 297
 298         if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE])
 299                 return -EINVAL;
 300
 301         helper_name = nla_data(tb[NFCTH_NAME]);
 302
 303         ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
 304         if (ret < 0)
 305                 return ret;
 306
 307         rcu_read_lock();
 308         for (i = 0; i < nf_ct_helper_hsize && !helper; i++) {
 309                 hlist_for_each_entry_rcu(cur, &nf_ct_helper_hash[i], hnode) {
 310
 311                         /* skip non-userspace conntrack helpers. */
 312                         if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 313                                 continue;
 314
 315                         if (strncmp(cur->name, helper_name,
 316                                         NF_CT_HELPER_NAME_LEN) != 0)
 317                                 continue;
 318
 319                         if ((tuple.src.l3num != cur->tuple.src.l3num ||
 320                              tuple.dst.protonum != cur->tuple.dst.protonum))
 321                                 continue;
 322
 323                         if (nlh->nlmsg_flags & NLM_F_EXCL) {
 324                                 ret = -EEXIST;
 325                                 goto err;
 326                         }
 327                         helper = cur;
 328                         break;
 329                 }
 330         }
 331         rcu_read_unlock();
 332
 333         if (helper == NULL)
 334                 ret = nfnl_cthelper_create(tb, &tuple);
 335         else
 336                 ret = nfnl_cthelper_update(tb, helper);
 337
 338         return ret;
 339 err:
 340         rcu_read_unlock();
 341         return ret;
 342 }
 343
 344 static int
 345 nfnl_cthelper_dump_tuple(struct sk_buff *skb,
 346                          struct nf_conntrack_helper *helper)
 347 {
 348         struct nlattr *nest_parms;
 349
 350         nest_parms = nla_nest_start(skb, NFCTH_TUPLE | NLA_F_NESTED);
 351         if (nest_parms == NULL)
 352                 goto nla_put_failure;
 353
 354         if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
 355                          htons(helper->tuple.src.l3num)))
 356                 goto nla_put_failure;
 357
 358         if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
 359                 goto nla_put_failure;
 360
 361         nla_nest_end(skb, nest_parms);
 362         return 0;
 363
 364 nla_put_failure:
 365         return -1;
 366 }
 367
 368 static int
 369 nfnl_cthelper_dump_policy(struct sk_buff *skb,
 370                         struct nf_conntrack_helper *helper)
 371 {
 372         int i;
 373         struct nlattr *nest_parms1, *nest_parms2;
 374
 375         nest_parms1 = nla_nest_start(skb, NFCTH_POLICY | NLA_F_NESTED);
 376         if (nest_parms1 == NULL)
 377                 goto nla_put_failure;
 378
 379         if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
 380                          htonl(helper->expect_class_max)))
 381                 goto nla_put_failure;
 382
 383         for (i=0; i<helper->expect_class_max; i++) {
 384                 nest_parms2 = nla_nest_start(skb,
 385                                 (NFCTH_POLICY_SET+i) | NLA_F_NESTED);
 386                 if (nest_parms2 == NULL)
 387                         goto nla_put_failure;
 388
 389                 if (nla_put_string(skb, NFCTH_POLICY_NAME,
 390                                    helper->expect_policy[i].name))
 391                         goto nla_put_failure;
 392
 393                 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
 394                                  htonl(helper->expect_policy[i].max_expected)))
 395                         goto nla_put_failure;
 396
 397                 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
 398                                  htonl(helper->expect_policy[i].timeout)))
 399                         goto nla_put_failure;
 400
 401                 nla_nest_end(skb, nest_parms2);
 402         }
 403         nla_nest_end(skb, nest_parms1);
 404         return 0;
 405
 406 nla_put_failure:
 407         return -1;
 408 }
 409
 410 static int
 411 nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
 412                         int event, struct nf_conntrack_helper *helper)
 413 {
 414         struct nlmsghdr *nlh;
 415         struct nfgenmsg *nfmsg;
 416         unsigned int flags = portid ? NLM_F_MULTI : 0;
 417         int status;
 418
 419         event |= NFNL_SUBSYS_CTHELPER << 8;
 420         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
 421         if (nlh == NULL)
 422                 goto nlmsg_failure;
 423
 424         nfmsg = nlmsg_data(nlh);
 425         nfmsg->nfgen_family = AF_UNSPEC;
 426         nfmsg->version = NFNETLINK_V0;
 427         nfmsg->res_id = 0;
 428
 429         if (nla_put_string(skb, NFCTH_NAME, helper->name))
 430                 goto nla_put_failure;
 431
 432         if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
 433                 goto nla_put_failure;
 434
 435         if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
 436                 goto nla_put_failure;
 437
 438         if (nfnl_cthelper_dump_policy(skb, helper) < 0)
 439                 goto nla_put_failure;
 440
 441         if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
 442                 goto nla_put_failure;
 443
 444         if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
 445                 status = NFCT_HELPER_STATUS_ENABLED;
 446         else
 447                 status = NFCT_HELPER_STATUS_DISABLED;
 448
 449         if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
 450                 goto nla_put_failure;
 451
 452         nlmsg_end(skb, nlh);
 453         return skb->len;
 454
 455 nlmsg_failure:
 456 nla_put_failure:
 457         nlmsg_cancel(skb, nlh);
 458         return -1;
 459 }
 460
 461 static int
 462 nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
 463 {
 464         struct nf_conntrack_helper *cur, *last;
 465
 466         rcu_read_lock();
 467         last = (struct nf_conntrack_helper *)cb->args[1];
 468         for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
 469 restart:
 470                 hlist_for_each_entry_rcu(cur,
 471                                 &nf_ct_helper_hash[cb->args[0]], hnode) {
 472
 473                         /* skip non-userspace conntrack helpers. */
 474                         if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 475                                 continue;
 476
 477                         if (cb->args[1]) {
 478                                 if (cur != last)
 479                                         continue;
 480                                 cb->args[1] = 0;
 481                         }
 482                         if (nfnl_cthelper_fill_info(skb,
 483                                             NETLINK_CB(cb->skb).portid,
 484                                             cb->nlh->nlmsg_seq,
 485                                             NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
 486                                             NFNL_MSG_CTHELPER_NEW, cur) < 0) {
 487                                 cb->args[1] = (unsigned long)cur;
 488                                 goto out;
 489                         }
 490                 }
 491         }
 492         if (cb->args[1]) {
 493                 cb->args[1] = 0;
 494                 goto restart;
 495         }
 496 out:
 497         rcu_read_unlock();
 498         return skb->len;
 499 }
 500
 501 static int
 502 nfnl_cthelper_get(struct sock *nfnl, struct sk_buff *skb,
 503                   const struct nlmsghdr *nlh, const struct nlattr * const tb[])
 504 {
 505         int ret = -ENOENT, i;
 506         struct nf_conntrack_helper *cur;
 507         struct sk_buff *skb2;
 508         char *helper_name = NULL;
 509         struct nf_conntrack_tuple tuple;
 510         bool tuple_set = false;
 511
 512         if (nlh->nlmsg_flags & NLM_F_DUMP) {
 513                 struct netlink_dump_control c = {
 514                         .dump = nfnl_cthelper_dump_table,
 515                 };
 516                 return netlink_dump_start(nfnl, skb, nlh, &c);
 517         }
 518
 519         if (tb[NFCTH_NAME])
 520                 helper_name = nla_data(tb[NFCTH_NAME]);
 521
 522         if (tb[NFCTH_TUPLE]) {
 523                 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
 524                 if (ret < 0)
 525                         return ret;
 526
 527                 tuple_set = true;
 528         }
 529
 530         for (i = 0; i < nf_ct_helper_hsize; i++) {
 531                 hlist_for_each_entry_rcu(cur, &nf_ct_helper_hash[i], hnode) {
 532
 533                         /* skip non-userspace conntrack helpers. */
 534                         if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 535                                 continue;
 536
 537                         if (helper_name && strncmp(cur->name, helper_name,
 538                                                 NF_CT_HELPER_NAME_LEN) != 0) {
 539                                 continue;
 540                         }
 541                         if (tuple_set &&
 542                             (tuple.src.l3num != cur->tuple.src.l3num ||
 543                              tuple.dst.protonum != cur->tuple.dst.protonum))
 544                                 continue;
 545
 546                         skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 547                         if (skb2 == NULL) {
 548                                 ret = -ENOMEM;
 549                                 break;
 550                         }
 551
 552                         ret = nfnl_cthelper_fill_info(skb2, NETLINK_CB(skb).portid,
 553                                                 nlh->nlmsg_seq,
 554                                                 NFNL_MSG_TYPE(nlh->nlmsg_type),
 555                                                 NFNL_MSG_CTHELPER_NEW, cur);
 556                         if (ret <= 0) {
 557                                 kfree_skb(skb2);
 558                                 break;
 559                         }
 560
 561                         ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
 562                                                 MSG_DONTWAIT);
 563                         if (ret > 0)
 564                                 ret = 0;
 565
 566                         /* this avoids a loop in nfnetlink. */
 567                         return ret == -EAGAIN ? -ENOBUFS : ret;
 568                 }
 569         }
 570         return ret;
 571 }
 572
 573 static int
 574 nfnl_cthelper_del(struct sock *nfnl, struct sk_buff *skb,
 575              const struct nlmsghdr *nlh, const struct nlattr * const tb[])
 576 {
 577         char *helper_name = NULL;
 578         struct nf_conntrack_helper *cur;
 579         struct hlist_node *tmp;
 580         struct nf_conntrack_tuple tuple;
 581         bool tuple_set = false, found = false;
 582         int i, j = 0, ret;
 583
 584         if (tb[NFCTH_NAME])
 585                 helper_name = nla_data(tb[NFCTH_NAME]);
 586
 587         if (tb[NFCTH_TUPLE]) {
 588                 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
 589                 if (ret < 0)
 590                         return ret;
 591
 592                 tuple_set = true;
 593         }
 594
 595         for (i = 0; i < nf_ct_helper_hsize; i++) {
 596                 hlist_for_each_entry_safe(cur, tmp, &nf_ct_helper_hash[i],
 597                                                                 hnode) {
 598                         /* skip non-userspace conntrack helpers. */
 599                         if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 600                                 continue;
 601
 602                         j++;
 603
 604                         if (helper_name && strncmp(cur->name, helper_name,
 605                                                 NF_CT_HELPER_NAME_LEN) != 0) {
 606                                 continue;
 607                         }
 608                         if (tuple_set &&
 609                             (tuple.src.l3num != cur->tuple.src.l3num ||
 610                              tuple.dst.protonum != cur->tuple.dst.protonum))
 611                                 continue;
 612
 613                         found = true;
 614                         nf_conntrack_helper_unregister(cur);
 615                 }
 616         }
 617         /* Make sure we return success if we flush and there is no helpers */
 618         return (found || j == 0) ? 0 : -ENOENT;
 619 }
 620
 621 static const struct nla_policy nfnl_cthelper_policy[NFCTH_MAX+1] = {
 622         [NFCTH_NAME] = { .type = NLA_NUL_STRING,
 623                          .len = NF_CT_HELPER_NAME_LEN-1 },
 624         [NFCTH_QUEUE_NUM] = { .type = NLA_U32, },
 625 };
 626
 627 static const struct nfnl_callback nfnl_cthelper_cb[NFNL_MSG_CTHELPER_MAX] = {
 628         [NFNL_MSG_CTHELPER_NEW]         = { .call = nfnl_cthelper_new,
 629                                             .attr_count = NFCTH_MAX,
 630                                             .policy = nfnl_cthelper_policy },
 631         [NFNL_MSG_CTHELPER_GET]         = { .call = nfnl_cthelper_get,
 632                                             .attr_count = NFCTH_MAX,
 633                                             .policy = nfnl_cthelper_policy },
 634         [NFNL_MSG_CTHELPER_DEL]         = { .call = nfnl_cthelper_del,
 635                                             .attr_count = NFCTH_MAX,
 636                                             .policy = nfnl_cthelper_policy },
 637 };
 638
 639 static const struct nfnetlink_subsystem nfnl_cthelper_subsys = {
 640         .name                           = "cthelper",
 641         .subsys_id                      = NFNL_SUBSYS_CTHELPER,
 642         .cb_count                       = NFNL_MSG_CTHELPER_MAX,
 643         .cb                             = nfnl_cthelper_cb,
 644 };
 645
 646 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);
 647
 648 static int __init nfnl_cthelper_init(void)
 649 {
 650         int ret;
 651
 652         ret = nfnetlink_subsys_register(&nfnl_cthelper_subsys);
 653         if (ret < 0) {
 654                 pr_err("nfnl_cthelper: cannot register with nfnetlink.\n");
 655                 goto err_out;
 656         }
 657         return 0;
 658 err_out:
 659         return ret;
 660 }
 661
 662 static void __exit nfnl_cthelper_exit(void)
 663 {
 664         struct nf_conntrack_helper *cur;
 665         struct hlist_node *tmp;
 666         int i;
 667
 668         nfnetlink_subsys_unregister(&nfnl_cthelper_subsys);
 669
 670         for (i=0; i<nf_ct_helper_hsize; i++) {
 671                 hlist_for_each_entry_safe(cur, tmp, &nf_ct_helper_hash[i],
 672                                                                         hnode) {
 673                         /* skip non-userspace conntrack helpers. */
 674                         if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 675                                 continue;
 676
 677                         nf_conntrack_helper_unregister(cur);
 678                 }
 679         }
 680 }
 681
 682 module_init(nfnl_cthelper_init);
 683 module_exit(nfnl_cthelper_exit);