linux/net/netfilter/nf_conntrack_ftp.c
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   1/* FTP extension for connection tracking. */
   2
   3/* (C) 1999-2001 Paul `Rusty' Russell
   4 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
   5 * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
   6 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License version 2 as
  10 * published by the Free Software Foundation.
  11 */
  12
  13#include <linux/module.h>
  14#include <linux/moduleparam.h>
  15#include <linux/netfilter.h>
  16#include <linux/ip.h>
  17#include <linux/slab.h>
  18#include <linux/ipv6.h>
  19#include <linux/ctype.h>
  20#include <linux/inet.h>
  21#include <net/checksum.h>
  22#include <net/tcp.h>
  23
  24#include <net/netfilter/nf_conntrack.h>
  25#include <net/netfilter/nf_conntrack_expect.h>
  26#include <net/netfilter/nf_conntrack_ecache.h>
  27#include <net/netfilter/nf_conntrack_helper.h>
  28#include <linux/netfilter/nf_conntrack_ftp.h>
  29
  30MODULE_LICENSE("GPL");
  31MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
  32MODULE_DESCRIPTION("ftp connection tracking helper");
  33MODULE_ALIAS("ip_conntrack_ftp");
  34MODULE_ALIAS_NFCT_HELPER("ftp");
  35
  36/* This is slow, but it's simple. --RR */
  37static char *ftp_buffer;
  38
  39static DEFINE_SPINLOCK(nf_ftp_lock);
  40
  41#define MAX_PORTS 8
  42static u_int16_t ports[MAX_PORTS];
  43static unsigned int ports_c;
  44module_param_array(ports, ushort, &ports_c, 0400);
  45
  46static bool loose;
  47module_param(loose, bool, 0600);
  48
  49unsigned int (*nf_nat_ftp_hook)(struct sk_buff *skb,
  50                                enum ip_conntrack_info ctinfo,
  51                                enum nf_ct_ftp_type type,
  52                                unsigned int protoff,
  53                                unsigned int matchoff,
  54                                unsigned int matchlen,
  55                                struct nf_conntrack_expect *exp);
  56EXPORT_SYMBOL_GPL(nf_nat_ftp_hook);
  57
  58static int try_rfc959(const char *, size_t, struct nf_conntrack_man *,
  59                      char, unsigned int *);
  60static int try_rfc1123(const char *, size_t, struct nf_conntrack_man *,
  61                       char, unsigned int *);
  62static int try_eprt(const char *, size_t, struct nf_conntrack_man *,
  63                    char, unsigned int *);
  64static int try_epsv_response(const char *, size_t, struct nf_conntrack_man *,
  65                             char, unsigned int *);
  66
  67static struct ftp_search {
  68        const char *pattern;
  69        size_t plen;
  70        char skip;
  71        char term;
  72        enum nf_ct_ftp_type ftptype;
  73        int (*getnum)(const char *, size_t, struct nf_conntrack_man *, char, unsigned int *);
  74} search[IP_CT_DIR_MAX][2] = {
  75        [IP_CT_DIR_ORIGINAL] = {
  76                {
  77                        .pattern        = "PORT",
  78                        .plen           = sizeof("PORT") - 1,
  79                        .skip           = ' ',
  80                        .term           = '\r',
  81                        .ftptype        = NF_CT_FTP_PORT,
  82                        .getnum         = try_rfc959,
  83                },
  84                {
  85                        .pattern        = "EPRT",
  86                        .plen           = sizeof("EPRT") - 1,
  87                        .skip           = ' ',
  88                        .term           = '\r',
  89                        .ftptype        = NF_CT_FTP_EPRT,
  90                        .getnum         = try_eprt,
  91                },
  92        },
  93        [IP_CT_DIR_REPLY] = {
  94                {
  95                        .pattern        = "227 ",
  96                        .plen           = sizeof("227 ") - 1,
  97                        .ftptype        = NF_CT_FTP_PASV,
  98                        .getnum         = try_rfc1123,
  99                },
 100                {
 101                        .pattern        = "229 ",
 102                        .plen           = sizeof("229 ") - 1,
 103                        .skip           = '(',
 104                        .term           = ')',
 105                        .ftptype        = NF_CT_FTP_EPSV,
 106                        .getnum         = try_epsv_response,
 107                },
 108        },
 109};
 110
 111static int
 112get_ipv6_addr(const char *src, size_t dlen, struct in6_addr *dst, u_int8_t term)
 113{
 114        const char *end;
 115        int ret = in6_pton(src, min_t(size_t, dlen, 0xffff), (u8 *)dst, term, &end);
 116        if (ret > 0)
 117                return (int)(end - src);
 118        return 0;
 119}
 120
 121static int try_number(const char *data, size_t dlen, u_int32_t array[],
 122                      int array_size, char sep, char term)
 123{
 124        u_int32_t i, len;
 125
 126        memset(array, 0, sizeof(array[0])*array_size);
 127
 128        /* Keep data pointing at next char. */
 129        for (i = 0, len = 0; len < dlen && i < array_size; len++, data++) {
 130                if (*data >= '0' && *data <= '9') {
 131                        array[i] = array[i]*10 + *data - '0';
 132                }
 133                else if (*data == sep)
 134                        i++;
 135                else {
 136                        /* Unexpected character; true if it's the
 137                           terminator (or we don't care about one)
 138                           and we're finished. */
 139                        if ((*data == term || !term) && i == array_size - 1)
 140                                return len;
 141
 142                        pr_debug("Char %u (got %u nums) `%u' unexpected\n",
 143                                 len, i, *data);
 144                        return 0;
 145                }
 146        }
 147        pr_debug("Failed to fill %u numbers separated by %c\n",
 148                 array_size, sep);
 149        return 0;
 150}
 151
 152/* Returns 0, or length of numbers: 192,168,1,1,5,6 */
 153static int try_rfc959(const char *data, size_t dlen,
 154                      struct nf_conntrack_man *cmd, char term,
 155                      unsigned int *offset)
 156{
 157        int length;
 158        u_int32_t array[6];
 159
 160        length = try_number(data, dlen, array, 6, ',', term);
 161        if (length == 0)
 162                return 0;
 163
 164        cmd->u3.ip =  htonl((array[0] << 24) | (array[1] << 16) |
 165                                    (array[2] << 8) | array[3]);
 166        cmd->u.tcp.port = htons((array[4] << 8) | array[5]);
 167        return length;
 168}
 169
 170/*
 171 * From RFC 1123:
 172 * The format of the 227 reply to a PASV command is not
 173 * well standardized.  In particular, an FTP client cannot
 174 * assume that the parentheses shown on page 40 of RFC-959
 175 * will be present (and in fact, Figure 3 on page 43 omits
 176 * them).  Therefore, a User-FTP program that interprets
 177 * the PASV reply must scan the reply for the first digit
 178 * of the host and port numbers.
 179 */
 180static int try_rfc1123(const char *data, size_t dlen,
 181                       struct nf_conntrack_man *cmd, char term,
 182                       unsigned int *offset)
 183{
 184        int i;
 185        for (i = 0; i < dlen; i++)
 186                if (isdigit(data[i]))
 187                        break;
 188
 189        if (i == dlen)
 190                return 0;
 191
 192        *offset += i;
 193
 194        return try_rfc959(data + i, dlen - i, cmd, 0, offset);
 195}
 196
 197/* Grab port: number up to delimiter */
 198static int get_port(const char *data, int start, size_t dlen, char delim,
 199                    __be16 *port)
 200{
 201        u_int16_t tmp_port = 0;
 202        int i;
 203
 204        for (i = start; i < dlen; i++) {
 205                /* Finished? */
 206                if (data[i] == delim) {
 207                        if (tmp_port == 0)
 208                                break;
 209                        *port = htons(tmp_port);
 210                        pr_debug("get_port: return %d\n", tmp_port);
 211                        return i + 1;
 212                }
 213                else if (data[i] >= '0' && data[i] <= '9')
 214                        tmp_port = tmp_port*10 + data[i] - '0';
 215                else { /* Some other crap */
 216                        pr_debug("get_port: invalid char.\n");
 217                        break;
 218                }
 219        }
 220        return 0;
 221}
 222
 223/* Returns 0, or length of numbers: |1|132.235.1.2|6275| or |2|3ffe::1|6275| */
 224static int try_eprt(const char *data, size_t dlen, struct nf_conntrack_man *cmd,
 225                    char term, unsigned int *offset)
 226{
 227        char delim;
 228        int length;
 229
 230        /* First character is delimiter, then "1" for IPv4 or "2" for IPv6,
 231           then delimiter again. */
 232        if (dlen <= 3) {
 233                pr_debug("EPRT: too short\n");
 234                return 0;
 235        }
 236        delim = data[0];
 237        if (isdigit(delim) || delim < 33 || delim > 126 || data[2] != delim) {
 238                pr_debug("try_eprt: invalid delimitter.\n");
 239                return 0;
 240        }
 241
 242        if ((cmd->l3num == PF_INET && data[1] != '1') ||
 243            (cmd->l3num == PF_INET6 && data[1] != '2')) {
 244                pr_debug("EPRT: invalid protocol number.\n");
 245                return 0;
 246        }
 247
 248        pr_debug("EPRT: Got %c%c%c\n", delim, data[1], delim);
 249
 250        if (data[1] == '1') {
 251                u_int32_t array[4];
 252
 253                /* Now we have IP address. */
 254                length = try_number(data + 3, dlen - 3, array, 4, '.', delim);
 255                if (length != 0)
 256                        cmd->u3.ip = htonl((array[0] << 24) | (array[1] << 16)
 257                                           | (array[2] << 8) | array[3]);
 258        } else {
 259                /* Now we have IPv6 address. */
 260                length = get_ipv6_addr(data + 3, dlen - 3,
 261                                       (struct in6_addr *)cmd->u3.ip6, delim);
 262        }
 263
 264        if (length == 0)
 265                return 0;
 266        pr_debug("EPRT: Got IP address!\n");
 267        /* Start offset includes initial "|1|", and trailing delimiter */
 268        return get_port(data, 3 + length + 1, dlen, delim, &cmd->u.tcp.port);
 269}
 270
 271/* Returns 0, or length of numbers: |||6446| */
 272static int try_epsv_response(const char *data, size_t dlen,
 273                             struct nf_conntrack_man *cmd, char term,
 274                             unsigned int *offset)
 275{
 276        char delim;
 277
 278        /* Three delimiters. */
 279        if (dlen <= 3) return 0;
 280        delim = data[0];
 281        if (isdigit(delim) || delim < 33 || delim > 126 ||
 282            data[1] != delim || data[2] != delim)
 283                return 0;
 284
 285        return get_port(data, 3, dlen, delim, &cmd->u.tcp.port);
 286}
 287
 288/* Return 1 for match, 0 for accept, -1 for partial. */
 289static int find_pattern(const char *data, size_t dlen,
 290                        const char *pattern, size_t plen,
 291                        char skip, char term,
 292                        unsigned int *numoff,
 293                        unsigned int *numlen,
 294                        struct nf_conntrack_man *cmd,
 295                        int (*getnum)(const char *, size_t,
 296                                      struct nf_conntrack_man *, char,
 297                                      unsigned int *))
 298{
 299        size_t i = plen;
 300
 301        pr_debug("find_pattern `%s': dlen = %Zu\n", pattern, dlen);
 302        if (dlen == 0)
 303                return 0;
 304
 305        if (dlen <= plen) {
 306                /* Short packet: try for partial? */
 307                if (strnicmp(data, pattern, dlen) == 0)
 308                        return -1;
 309                else return 0;
 310        }
 311
 312        if (strnicmp(data, pattern, plen) != 0) {
 313#if 0
 314                size_t i;
 315
 316                pr_debug("ftp: string mismatch\n");
 317                for (i = 0; i < plen; i++) {
 318                        pr_debug("ftp:char %u `%c'(%u) vs `%c'(%u)\n",
 319                                 i, data[i], data[i],
 320                                 pattern[i], pattern[i]);
 321                }
 322#endif
 323                return 0;
 324        }
 325
 326        pr_debug("Pattern matches!\n");
 327        /* Now we've found the constant string, try to skip
 328           to the 'skip' character */
 329        if (skip) {
 330                for (i = plen; data[i] != skip; i++)
 331                        if (i == dlen - 1) return -1;
 332
 333                /* Skip over the last character */
 334                i++;
 335        }
 336
 337        pr_debug("Skipped up to `%c'!\n", skip);
 338
 339        *numoff = i;
 340        *numlen = getnum(data + i, dlen - i, cmd, term, numoff);
 341        if (!*numlen)
 342                return -1;
 343
 344        pr_debug("Match succeeded!\n");
 345        return 1;
 346}
 347
 348/* Look up to see if we're just after a \n. */
 349static int find_nl_seq(u32 seq, const struct nf_ct_ftp_master *info, int dir)
 350{
 351        unsigned int i;
 352
 353        for (i = 0; i < info->seq_aft_nl_num[dir]; i++)
 354                if (info->seq_aft_nl[dir][i] == seq)
 355                        return 1;
 356        return 0;
 357}
 358
 359/* We don't update if it's older than what we have. */
 360static void update_nl_seq(struct nf_conn *ct, u32 nl_seq,
 361                          struct nf_ct_ftp_master *info, int dir,
 362                          struct sk_buff *skb)
 363{
 364        unsigned int i, oldest;
 365
 366        /* Look for oldest: if we find exact match, we're done. */
 367        for (i = 0; i < info->seq_aft_nl_num[dir]; i++) {
 368                if (info->seq_aft_nl[dir][i] == nl_seq)
 369                        return;
 370        }
 371
 372        if (info->seq_aft_nl_num[dir] < NUM_SEQ_TO_REMEMBER) {
 373                info->seq_aft_nl[dir][info->seq_aft_nl_num[dir]++] = nl_seq;
 374        } else {
 375                if (before(info->seq_aft_nl[dir][0], info->seq_aft_nl[dir][1]))
 376                        oldest = 0;
 377                else
 378                        oldest = 1;
 379
 380                if (after(nl_seq, info->seq_aft_nl[dir][oldest]))
 381                        info->seq_aft_nl[dir][oldest] = nl_seq;
 382        }
 383}
 384
 385static int help(struct sk_buff *skb,
 386                unsigned int protoff,
 387                struct nf_conn *ct,
 388                enum ip_conntrack_info ctinfo)
 389{
 390        unsigned int dataoff, datalen;
 391        const struct tcphdr *th;
 392        struct tcphdr _tcph;
 393        const char *fb_ptr;
 394        int ret;
 395        u32 seq;
 396        int dir = CTINFO2DIR(ctinfo);
 397        unsigned int uninitialized_var(matchlen), uninitialized_var(matchoff);
 398        struct nf_ct_ftp_master *ct_ftp_info = nfct_help_data(ct);
 399        struct nf_conntrack_expect *exp;
 400        union nf_inet_addr *daddr;
 401        struct nf_conntrack_man cmd = {};
 402        unsigned int i;
 403        int found = 0, ends_in_nl;
 404        typeof(nf_nat_ftp_hook) nf_nat_ftp;
 405
 406        /* Until there's been traffic both ways, don't look in packets. */
 407        if (ctinfo != IP_CT_ESTABLISHED &&
 408            ctinfo != IP_CT_ESTABLISHED_REPLY) {
 409                pr_debug("ftp: Conntrackinfo = %u\n", ctinfo);
 410                return NF_ACCEPT;
 411        }
 412
 413        th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph);
 414        if (th == NULL)
 415                return NF_ACCEPT;
 416
 417        dataoff = protoff + th->doff * 4;
 418        /* No data? */
 419        if (dataoff >= skb->len) {
 420                pr_debug("ftp: dataoff(%u) >= skblen(%u)\n", dataoff,
 421                         skb->len);
 422                return NF_ACCEPT;
 423        }
 424        datalen = skb->len - dataoff;
 425
 426        spin_lock_bh(&nf_ftp_lock);
 427        fb_ptr = skb_header_pointer(skb, dataoff, datalen, ftp_buffer);
 428        BUG_ON(fb_ptr == NULL);
 429
 430        ends_in_nl = (fb_ptr[datalen - 1] == '\n');
 431        seq = ntohl(th->seq) + datalen;
 432
 433        /* Look up to see if we're just after a \n. */
 434        if (!find_nl_seq(ntohl(th->seq), ct_ftp_info, dir)) {
 435                /* We're picking up this, clear flags and let it continue */
 436                if (unlikely(ct_ftp_info->flags[dir] & NF_CT_FTP_SEQ_PICKUP)) {
 437                        ct_ftp_info->flags[dir] ^= NF_CT_FTP_SEQ_PICKUP;
 438                        goto skip_nl_seq;
 439                }
 440
 441                /* Now if this ends in \n, update ftp info. */
 442                pr_debug("nf_conntrack_ftp: wrong seq pos %s(%u) or %s(%u)\n",
 443                         ct_ftp_info->seq_aft_nl_num[dir] > 0 ? "" : "(UNSET)",
 444                         ct_ftp_info->seq_aft_nl[dir][0],
 445                         ct_ftp_info->seq_aft_nl_num[dir] > 1 ? "" : "(UNSET)",
 446                         ct_ftp_info->seq_aft_nl[dir][1]);
 447                ret = NF_ACCEPT;
 448                goto out_update_nl;
 449        }
 450
 451skip_nl_seq:
 452        /* Initialize IP/IPv6 addr to expected address (it's not mentioned
 453           in EPSV responses) */
 454        cmd.l3num = nf_ct_l3num(ct);
 455        memcpy(cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all,
 456               sizeof(cmd.u3.all));
 457
 458        for (i = 0; i < ARRAY_SIZE(search[dir]); i++) {
 459                found = find_pattern(fb_ptr, datalen,
 460                                     search[dir][i].pattern,
 461                                     search[dir][i].plen,
 462                                     search[dir][i].skip,
 463                                     search[dir][i].term,
 464                                     &matchoff, &matchlen,
 465                                     &cmd,
 466                                     search[dir][i].getnum);
 467                if (found) break;
 468        }
 469        if (found == -1) {
 470                /* We don't usually drop packets.  After all, this is
 471                   connection tracking, not packet filtering.
 472                   However, it is necessary for accurate tracking in
 473                   this case. */
 474                nf_ct_helper_log(skb, ct, "partial matching of `%s'",
 475                                 search[dir][i].pattern);
 476                ret = NF_DROP;
 477                goto out;
 478        } else if (found == 0) { /* No match */
 479                ret = NF_ACCEPT;
 480                goto out_update_nl;
 481        }
 482
 483        pr_debug("conntrack_ftp: match `%.*s' (%u bytes at %u)\n",
 484                 matchlen, fb_ptr + matchoff,
 485                 matchlen, ntohl(th->seq) + matchoff);
 486
 487        exp = nf_ct_expect_alloc(ct);
 488        if (exp == NULL) {
 489                nf_ct_helper_log(skb, ct, "cannot alloc expectation");
 490                ret = NF_DROP;
 491                goto out;
 492        }
 493
 494        /* We refer to the reverse direction ("!dir") tuples here,
 495         * because we're expecting something in the other direction.
 496         * Doesn't matter unless NAT is happening.  */
 497        daddr = &ct->tuplehash[!dir].tuple.dst.u3;
 498
 499        /* Update the ftp info */
 500        if ((cmd.l3num == nf_ct_l3num(ct)) &&
 501            memcmp(&cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all,
 502                     sizeof(cmd.u3.all))) {
 503                /* Enrico Scholz's passive FTP to partially RNAT'd ftp
 504                   server: it really wants us to connect to a
 505                   different IP address.  Simply don't record it for
 506                   NAT. */
 507                if (cmd.l3num == PF_INET) {
 508                        pr_debug("conntrack_ftp: NOT RECORDING: %pI4 != %pI4\n",
 509                                 &cmd.u3.ip,
 510                                 &ct->tuplehash[dir].tuple.src.u3.ip);
 511                } else {
 512                        pr_debug("conntrack_ftp: NOT RECORDING: %pI6 != %pI6\n",
 513                                 cmd.u3.ip6,
 514                                 ct->tuplehash[dir].tuple.src.u3.ip6);
 515                }
 516
 517                /* Thanks to Cristiano Lincoln Mattos
 518                   <lincoln@cesar.org.br> for reporting this potential
 519                   problem (DMZ machines opening holes to internal
 520                   networks, or the packet filter itself). */
 521                if (!loose) {
 522                        ret = NF_ACCEPT;
 523                        goto out_put_expect;
 524                }
 525                daddr = &cmd.u3;
 526        }
 527
 528        nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, cmd.l3num,
 529                          &ct->tuplehash[!dir].tuple.src.u3, daddr,
 530                          IPPROTO_TCP, NULL, &cmd.u.tcp.port);
 531
 532        /* Now, NAT might want to mangle the packet, and register the
 533         * (possibly changed) expectation itself. */
 534        nf_nat_ftp = rcu_dereference(nf_nat_ftp_hook);
 535        if (nf_nat_ftp && ct->status & IPS_NAT_MASK)
 536                ret = nf_nat_ftp(skb, ctinfo, search[dir][i].ftptype,
 537                                 protoff, matchoff, matchlen, exp);
 538        else {
 539                /* Can't expect this?  Best to drop packet now. */
 540                if (nf_ct_expect_related(exp) != 0) {
 541                        nf_ct_helper_log(skb, ct, "cannot add expectation");
 542                        ret = NF_DROP;
 543                } else
 544                        ret = NF_ACCEPT;
 545        }
 546
 547out_put_expect:
 548        nf_ct_expect_put(exp);
 549
 550out_update_nl:
 551        /* Now if this ends in \n, update ftp info.  Seq may have been
 552         * adjusted by NAT code. */
 553        if (ends_in_nl)
 554                update_nl_seq(ct, seq, ct_ftp_info, dir, skb);
 555 out:
 556        spin_unlock_bh(&nf_ftp_lock);
 557        return ret;
 558}
 559
 560static int nf_ct_ftp_from_nlattr(struct nlattr *attr, struct nf_conn *ct)
 561{
 562        struct nf_ct_ftp_master *ftp = nfct_help_data(ct);
 563
 564        /* This conntrack has been injected from user-space, always pick up
 565         * sequence tracking. Otherwise, the first FTP command after the
 566         * failover breaks.
 567         */
 568        ftp->flags[IP_CT_DIR_ORIGINAL] |= NF_CT_FTP_SEQ_PICKUP;
 569        ftp->flags[IP_CT_DIR_REPLY] |= NF_CT_FTP_SEQ_PICKUP;
 570        return 0;
 571}
 572
 573static struct nf_conntrack_helper ftp[MAX_PORTS][2] __read_mostly;
 574
 575static const struct nf_conntrack_expect_policy ftp_exp_policy = {
 576        .max_expected   = 1,
 577        .timeout        = 5 * 60,
 578};
 579
 580/* don't make this __exit, since it's called from __init ! */
 581static void nf_conntrack_ftp_fini(void)
 582{
 583        int i, j;
 584        for (i = 0; i < ports_c; i++) {
 585                for (j = 0; j < 2; j++) {
 586                        if (ftp[i][j].me == NULL)
 587                                continue;
 588
 589                        pr_debug("nf_ct_ftp: unregistering helper for pf: %d "
 590                                 "port: %d\n",
 591                                 ftp[i][j].tuple.src.l3num, ports[i]);
 592                        nf_conntrack_helper_unregister(&ftp[i][j]);
 593                }
 594        }
 595
 596        kfree(ftp_buffer);
 597}
 598
 599static int __init nf_conntrack_ftp_init(void)
 600{
 601        int i, j = -1, ret = 0;
 602
 603        ftp_buffer = kmalloc(65536, GFP_KERNEL);
 604        if (!ftp_buffer)
 605                return -ENOMEM;
 606
 607        if (ports_c == 0)
 608                ports[ports_c++] = FTP_PORT;
 609
 610        /* FIXME should be configurable whether IPv4 and IPv6 FTP connections
 611                 are tracked or not - YK */
 612        for (i = 0; i < ports_c; i++) {
 613                ftp[i][0].tuple.src.l3num = PF_INET;
 614                ftp[i][1].tuple.src.l3num = PF_INET6;
 615                for (j = 0; j < 2; j++) {
 616                        ftp[i][j].data_len = sizeof(struct nf_ct_ftp_master);
 617                        ftp[i][j].tuple.src.u.tcp.port = htons(ports[i]);
 618                        ftp[i][j].tuple.dst.protonum = IPPROTO_TCP;
 619                        ftp[i][j].expect_policy = &ftp_exp_policy;
 620                        ftp[i][j].me = THIS_MODULE;
 621                        ftp[i][j].help = help;
 622                        ftp[i][j].from_nlattr = nf_ct_ftp_from_nlattr;
 623                        if (ports[i] == FTP_PORT)
 624                                sprintf(ftp[i][j].name, "ftp");
 625                        else
 626                                sprintf(ftp[i][j].name, "ftp-%d", ports[i]);
 627
 628                        pr_debug("nf_ct_ftp: registering helper for pf: %d "
 629                                 "port: %d\n",
 630                                 ftp[i][j].tuple.src.l3num, ports[i]);
 631                        ret = nf_conntrack_helper_register(&ftp[i][j]);
 632                        if (ret) {
 633                                printk(KERN_ERR "nf_ct_ftp: failed to register"
 634                                       " helper for pf: %d port: %d\n",
 635                                        ftp[i][j].tuple.src.l3num, ports[i]);
 636                                nf_conntrack_ftp_fini();
 637                                return ret;
 638                        }
 639                }
 640        }
 641
 642        return 0;
 643}
 644
 645module_init(nf_conntrack_ftp_init);
 646module_exit(nf_conntrack_ftp_fini);
 647
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