linux/net/netfilter/nfnetlink_cthelper.c
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   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
  31MODULE_LICENSE("GPL");
  32MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
  33MODULE_DESCRIPTION("nfnl_cthelper: User-space connection tracking helpers");
  34
  35static int
  36nfnl_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
  61static 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
  66static int
  67nfnl_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
  89static int
  90nfnl_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
 104static int
 105nfnl_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
 115nla_put_failure:
 116        return -ENOSPC;
 117}
 118
 119static 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
 126static int
 127nfnl_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
 152static const struct nla_policy
 153nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = {
 154        [NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, },
 155};
 156
 157static int
 158nfnl_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;
 196err:
 197        kfree(expect_policy);
 198        return -EINVAL;
 199}
 200
 201static int
 202nfnl_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;
 251err:
 252        kfree(helper);
 253        return ret;
 254}
 255
 256static int
 257nfnl_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
 289static int
 290nfnl_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;
 339err:
 340        rcu_read_unlock();
 341        return ret;
 342}
 343
 344static int
 345nfnl_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
 364nla_put_failure:
 365        return -1;
 366}
 367
 368static int
 369nfnl_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
 406nla_put_failure:
 407        return -1;
 408}
 409
 410static int
 411nfnl_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
 455nlmsg_failure:
 456nla_put_failure:
 457        nlmsg_cancel(skb, nlh);
 458        return -1;
 459}
 460
 461static int
 462nfnl_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]++) {
 469restart:
 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        }
 496out:
 497        rcu_read_unlock();
 498        return skb->len;
 499}
 500
 501static int
 502nfnl_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
 573static int
 574nfnl_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
 621static 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
 627static 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
 639static 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
 646MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);
 647
 648static 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;
 658err_out:
 659        return ret;
 660}
 661
 662static 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
 682module_init(nfnl_cthelper_init);
 683module_exit(nfnl_cthelper_exit);
 684