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        struct nlattr *tb[NFCTH_TUPLE_MAX+1];
  71
  72        nla_parse_nested(tb, NFCTH_TUPLE_MAX, attr, nfnl_cthelper_tuple_pol);
  73
  74        if (!tb[NFCTH_TUPLE_L3PROTONUM] || !tb[NFCTH_TUPLE_L4PROTONUM])
  75                return -EINVAL;
  76
  77        tuple->src.l3num = ntohs(nla_get_be16(tb[NFCTH_TUPLE_L3PROTONUM]));
  78        tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]);
  79
  80        return 0;
  81}
  82
  83static int
  84nfnl_cthelper_from_nlattr(struct nlattr *attr, struct nf_conn *ct)
  85{
  86        const struct nf_conn_help *help = nfct_help(ct);
  87
  88        if (attr == NULL)
  89                return -EINVAL;
  90
  91        if (help->helper->data_len == 0)
  92                return -EINVAL;
  93
  94        memcpy(&help->data, nla_data(attr), help->helper->data_len);
  95        return 0;
  96}
  97
  98static int
  99nfnl_cthelper_to_nlattr(struct sk_buff *skb, const struct nf_conn *ct)
 100{
 101        const struct nf_conn_help *help = nfct_help(ct);
 102
 103        if (help->helper->data_len &&
 104            nla_put(skb, CTA_HELP_INFO, help->helper->data_len, &help->data))
 105                goto nla_put_failure;
 106
 107        return 0;
 108
 109nla_put_failure:
 110        return -ENOSPC;
 111}
 112
 113static const struct nla_policy nfnl_cthelper_expect_pol[NFCTH_POLICY_MAX+1] = {
 114        [NFCTH_POLICY_NAME] = { .type = NLA_NUL_STRING,
 115                                .len = NF_CT_HELPER_NAME_LEN-1 },
 116        [NFCTH_POLICY_EXPECT_MAX] = { .type = NLA_U32, },
 117        [NFCTH_POLICY_EXPECT_TIMEOUT] = { .type = NLA_U32, },
 118};
 119
 120static int
 121nfnl_cthelper_expect_policy(struct nf_conntrack_expect_policy *expect_policy,
 122                            const struct nlattr *attr)
 123{
 124        struct nlattr *tb[NFCTH_POLICY_MAX+1];
 125
 126        nla_parse_nested(tb, NFCTH_POLICY_MAX, attr, nfnl_cthelper_expect_pol);
 127
 128        if (!tb[NFCTH_POLICY_NAME] ||
 129            !tb[NFCTH_POLICY_EXPECT_MAX] ||
 130            !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
 131                return -EINVAL;
 132
 133        strncpy(expect_policy->name,
 134                nla_data(tb[NFCTH_POLICY_NAME]), NF_CT_HELPER_NAME_LEN);
 135        expect_policy->max_expected =
 136                ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
 137        expect_policy->timeout =
 138                ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
 139
 140        return 0;
 141}
 142
 143static const struct nla_policy
 144nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = {
 145        [NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, },
 146};
 147
 148static int
 149nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
 150                                  const struct nlattr *attr)
 151{
 152        int i, ret;
 153        struct nf_conntrack_expect_policy *expect_policy;
 154        struct nlattr *tb[NFCTH_POLICY_SET_MAX+1];
 155
 156        nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
 157                                        nfnl_cthelper_expect_policy_set);
 158
 159        if (!tb[NFCTH_POLICY_SET_NUM])
 160                return -EINVAL;
 161
 162        helper->expect_class_max =
 163                ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
 164
 165        if (helper->expect_class_max != 0 &&
 166            helper->expect_class_max > NF_CT_MAX_EXPECT_CLASSES)
 167                return -EOVERFLOW;
 168
 169        expect_policy = kzalloc(sizeof(struct nf_conntrack_expect_policy) *
 170                                helper->expect_class_max, GFP_KERNEL);
 171        if (expect_policy == NULL)
 172                return -ENOMEM;
 173
 174        for (i=0; i<helper->expect_class_max; i++) {
 175                if (!tb[NFCTH_POLICY_SET+i])
 176                        goto err;
 177
 178                ret = nfnl_cthelper_expect_policy(&expect_policy[i],
 179                                                  tb[NFCTH_POLICY_SET+i]);
 180                if (ret < 0)
 181                        goto err;
 182        }
 183        helper->expect_policy = expect_policy;
 184        return 0;
 185err:
 186        kfree(expect_policy);
 187        return -EINVAL;
 188}
 189
 190static int
 191nfnl_cthelper_create(const struct nlattr * const tb[],
 192                     struct nf_conntrack_tuple *tuple)
 193{
 194        struct nf_conntrack_helper *helper;
 195        int ret;
 196
 197        if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN])
 198                return -EINVAL;
 199
 200        helper = kzalloc(sizeof(struct nf_conntrack_helper), GFP_KERNEL);
 201        if (helper == NULL)
 202                return -ENOMEM;
 203
 204        ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]);
 205        if (ret < 0)
 206                goto err;
 207
 208        strncpy(helper->name, nla_data(tb[NFCTH_NAME]), NF_CT_HELPER_NAME_LEN);
 209        helper->data_len = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
 210        helper->flags |= NF_CT_HELPER_F_USERSPACE;
 211        memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
 212
 213        helper->me = THIS_MODULE;
 214        helper->help = nfnl_userspace_cthelper;
 215        helper->from_nlattr = nfnl_cthelper_from_nlattr;
 216        helper->to_nlattr = nfnl_cthelper_to_nlattr;
 217
 218        /* Default to queue number zero, this can be updated at any time. */
 219        if (tb[NFCTH_QUEUE_NUM])
 220                helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
 221
 222        if (tb[NFCTH_STATUS]) {
 223                int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
 224
 225                switch(status) {
 226                case NFCT_HELPER_STATUS_ENABLED:
 227                        helper->flags |= NF_CT_HELPER_F_CONFIGURED;
 228                        break;
 229                case NFCT_HELPER_STATUS_DISABLED:
 230                        helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
 231                        break;
 232                }
 233        }
 234
 235        ret = nf_conntrack_helper_register(helper);
 236        if (ret < 0)
 237                goto err;
 238
 239        return 0;
 240err:
 241        kfree(helper);
 242        return ret;
 243}
 244
 245static int
 246nfnl_cthelper_update(const struct nlattr * const tb[],
 247                     struct nf_conntrack_helper *helper)
 248{
 249        int ret;
 250
 251        if (tb[NFCTH_PRIV_DATA_LEN])
 252                return -EBUSY;
 253
 254        if (tb[NFCTH_POLICY]) {
 255                ret = nfnl_cthelper_parse_expect_policy(helper,
 256                                                        tb[NFCTH_POLICY]);
 257                if (ret < 0)
 258                        return ret;
 259        }
 260        if (tb[NFCTH_QUEUE_NUM])
 261                helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
 262
 263        if (tb[NFCTH_STATUS]) {
 264                int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
 265
 266                switch(status) {
 267                case NFCT_HELPER_STATUS_ENABLED:
 268                        helper->flags |= NF_CT_HELPER_F_CONFIGURED;
 269                        break;
 270                case NFCT_HELPER_STATUS_DISABLED:
 271                        helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
 272                        break;
 273                }
 274        }
 275        return 0;
 276}
 277
 278static int
 279nfnl_cthelper_new(struct sock *nfnl, struct sk_buff *skb,
 280                  const struct nlmsghdr *nlh, const struct nlattr * const tb[])
 281{
 282        const char *helper_name;
 283        struct nf_conntrack_helper *cur, *helper = NULL;
 284        struct nf_conntrack_tuple tuple;
 285        struct hlist_node *n;
 286        int ret = 0, i;
 287
 288        if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE])
 289                return -EINVAL;
 290
 291        helper_name = nla_data(tb[NFCTH_NAME]);
 292
 293        ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
 294        if (ret < 0)
 295                return ret;
 296
 297        rcu_read_lock();
 298        for (i = 0; i < nf_ct_helper_hsize && !helper; i++) {
 299                hlist_for_each_entry_rcu(cur, n, &nf_ct_helper_hash[i], hnode) {
 300
 301                        /* skip non-userspace conntrack helpers. */
 302                        if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 303                                continue;
 304
 305                        if (strncmp(cur->name, helper_name,
 306                                        NF_CT_HELPER_NAME_LEN) != 0)
 307                                continue;
 308
 309                        if ((tuple.src.l3num != cur->tuple.src.l3num ||
 310                             tuple.dst.protonum != cur->tuple.dst.protonum))
 311                                continue;
 312
 313                        if (nlh->nlmsg_flags & NLM_F_EXCL) {
 314                                ret = -EEXIST;
 315                                goto err;
 316                        }
 317                        helper = cur;
 318                        break;
 319                }
 320        }
 321        rcu_read_unlock();
 322
 323        if (helper == NULL)
 324                ret = nfnl_cthelper_create(tb, &tuple);
 325        else
 326                ret = nfnl_cthelper_update(tb, helper);
 327
 328        return ret;
 329err:
 330        rcu_read_unlock();
 331        return ret;
 332}
 333
 334static int
 335nfnl_cthelper_dump_tuple(struct sk_buff *skb,
 336                         struct nf_conntrack_helper *helper)
 337{
 338        struct nlattr *nest_parms;
 339
 340        nest_parms = nla_nest_start(skb, NFCTH_TUPLE | NLA_F_NESTED);
 341        if (nest_parms == NULL)
 342                goto nla_put_failure;
 343
 344        if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
 345                         htons(helper->tuple.src.l3num)))
 346                goto nla_put_failure;
 347
 348        if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
 349                goto nla_put_failure;
 350
 351        nla_nest_end(skb, nest_parms);
 352        return 0;
 353
 354nla_put_failure:
 355        return -1;
 356}
 357
 358static int
 359nfnl_cthelper_dump_policy(struct sk_buff *skb,
 360                        struct nf_conntrack_helper *helper)
 361{
 362        int i;
 363        struct nlattr *nest_parms1, *nest_parms2;
 364
 365        nest_parms1 = nla_nest_start(skb, NFCTH_POLICY | NLA_F_NESTED);
 366        if (nest_parms1 == NULL)
 367                goto nla_put_failure;
 368
 369        if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
 370                         htonl(helper->expect_class_max)))
 371                goto nla_put_failure;
 372
 373        for (i=0; i<helper->expect_class_max; i++) {
 374                nest_parms2 = nla_nest_start(skb,
 375                                (NFCTH_POLICY_SET+i) | NLA_F_NESTED);
 376                if (nest_parms2 == NULL)
 377                        goto nla_put_failure;
 378
 379                if (nla_put_string(skb, NFCTH_POLICY_NAME,
 380                                   helper->expect_policy[i].name))
 381                        goto nla_put_failure;
 382
 383                if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
 384                                 htonl(helper->expect_policy[i].max_expected)))
 385                        goto nla_put_failure;
 386
 387                if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
 388                                 htonl(helper->expect_policy[i].timeout)))
 389                        goto nla_put_failure;
 390
 391                nla_nest_end(skb, nest_parms2);
 392        }
 393        nla_nest_end(skb, nest_parms1);
 394        return 0;
 395
 396nla_put_failure:
 397        return -1;
 398}
 399
 400static int
 401nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
 402                        int event, struct nf_conntrack_helper *helper)
 403{
 404        struct nlmsghdr *nlh;
 405        struct nfgenmsg *nfmsg;
 406        unsigned int flags = portid ? NLM_F_MULTI : 0;
 407        int status;
 408
 409        event |= NFNL_SUBSYS_CTHELPER << 8;
 410        nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
 411        if (nlh == NULL)
 412                goto nlmsg_failure;
 413
 414        nfmsg = nlmsg_data(nlh);
 415        nfmsg->nfgen_family = AF_UNSPEC;
 416        nfmsg->version = NFNETLINK_V0;
 417        nfmsg->res_id = 0;
 418
 419        if (nla_put_string(skb, NFCTH_NAME, helper->name))
 420                goto nla_put_failure;
 421
 422        if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
 423                goto nla_put_failure;
 424
 425        if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
 426                goto nla_put_failure;
 427
 428        if (nfnl_cthelper_dump_policy(skb, helper) < 0)
 429                goto nla_put_failure;
 430
 431        if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
 432                goto nla_put_failure;
 433
 434        if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
 435                status = NFCT_HELPER_STATUS_ENABLED;
 436        else
 437                status = NFCT_HELPER_STATUS_DISABLED;
 438
 439        if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
 440                goto nla_put_failure;
 441
 442        nlmsg_end(skb, nlh);
 443        return skb->len;
 444
 445nlmsg_failure:
 446nla_put_failure:
 447        nlmsg_cancel(skb, nlh);
 448        return -1;
 449}
 450
 451static int
 452nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
 453{
 454        struct nf_conntrack_helper *cur, *last;
 455        struct hlist_node *n;
 456
 457        rcu_read_lock();
 458        last = (struct nf_conntrack_helper *)cb->args[1];
 459        for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
 460restart:
 461                hlist_for_each_entry_rcu(cur, n,
 462                                &nf_ct_helper_hash[cb->args[0]], hnode) {
 463
 464                        /* skip non-userspace conntrack helpers. */
 465                        if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
 466                                continue;
 467
 468                        if (cb->args[1]) {
 469                                if (cur != last)
 470                                        continue;
 471                                cb->args[1] = 0;
 472                        }
 473                        if (nfnl_cthelper_fill_info(skb,
 474                                            NETLINK_CB(cb->skb).portid,
 475                                            cb->nlh->nlmsg_seq,
 476                                            NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
 477                                            NFNL_MSG_CTHELPER_NEW, cur) < 0) {
 478                                cb->args[1] = (unsigned long)cur;
 479                                goto out;
 480                        }
 481                }
 482        }
 483        if (cb->args[1]) {
 484                cb->args[1] = 0;
 485                goto restart;
 486        }
 487out:
 488        rcu_read_unlock();
 489        return skb->len;
 490}
 491
 492static int
 493nfnl_cthelper_get(struct sock *nfnl, struct sk_buff *skb,
 494                  const struct nlmsghdr *nlh, const struct nlattr * const tb[])
 495{
 496        int ret = -ENOENT, i;
 497        struct nf_conntrack_helper *cur;
 498        struct hlist_node *n;
 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, n, &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
 565static int
 566nfnl_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 *n, *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, n, 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
 613static 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
 619static 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
 631static 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
 638MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);
 639
 640static 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;
 650err_out:
 651        return ret;
 652}
 653
 654static void __exit nfnl_cthelper_exit(void)
 655{
 656        struct nf_conntrack_helper *cur;
 657        struct hlist_node *n, *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, n, 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
 674module_init(nfnl_cthelper_init);
 675module_exit(nfnl_cthelper_exit);
 676
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