net/netfilter/nf_conntrack_ftp.c

   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  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/moduleparam.h>
  14 #include <linux/netfilter.h>
  15 #include <linux/ip.h>
  16 #include <linux/ipv6.h>
  17 #include <linux/ctype.h>
  18 #include <linux/inet.h>
  19 #include <net/checksum.h>
  20 #include <net/tcp.h>
  21
  22 #include <net/netfilter/nf_conntrack.h>
  23 #include <net/netfilter/nf_conntrack_expect.h>
  24 #include <net/netfilter/nf_conntrack_ecache.h>
  25 #include <net/netfilter/nf_conntrack_helper.h>
  26 #include <linux/netfilter/nf_conntrack_ftp.h>
  27
  28 MODULE_LICENSE("GPL");
  29 MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
  30 MODULE_DESCRIPTION("ftp connection tracking helper");
  31 MODULE_ALIAS("ip_conntrack_ftp");
  32
  33 /* This is slow, but it's simple. --RR */
  34 static char *ftp_buffer;
  35
  36 static DEFINE_SPINLOCK(nf_ftp_lock);
  37
  38 #define MAX_PORTS 8
  39 static u_int16_t ports[MAX_PORTS];
  40 static unsigned int ports_c;
  41 module_param_array(ports, ushort, &ports_c, 0400);
  42
  43 static int loose;
  44 module_param(loose, bool, 0600);
  45
  46 unsigned int (*nf_nat_ftp_hook)(struct sk_buff **pskb,
  47                                 enum ip_conntrack_info ctinfo,
  48                                 enum nf_ct_ftp_type type,
  49                                 unsigned int matchoff,
  50                                 unsigned int matchlen,
  51                                 struct nf_conntrack_expect *exp,
  52                                 u32 *seq);
  53 EXPORT_SYMBOL_GPL(nf_nat_ftp_hook);
  54
  55 #if 0
  56 #define DEBUGP printk
  57 #else
  58 #define DEBUGP(format, args...)
  59 #endif
  60
  61 static int try_rfc959(const char *, size_t, struct nf_conntrack_man *, char);
  62 static int try_eprt(const char *, size_t, struct nf_conntrack_man *, char);
  63 static int try_epsv_response(const char *, size_t, struct nf_conntrack_man *,
  64                              char);
  65
  66 static struct ftp_search {
  67         const char *pattern;
  68         size_t plen;
  69         char skip;
  70         char term;
  71         enum nf_ct_ftp_type ftptype;
  72         int (*getnum)(const char *, size_t, struct nf_conntrack_man *, char);
  73 } search[IP_CT_DIR_MAX][2] = {
  74         [IP_CT_DIR_ORIGINAL] = {
  75                 {
  76                         .pattern        = "PORT",
  77                         .plen           = sizeof("PORT") - 1,
  78                         .skip           = ' ',
  79                         .term           = '\r',
  80                         .ftptype        = NF_CT_FTP_PORT,
  81                         .getnum         = try_rfc959,
  82                 },
  83                 {
  84                         .pattern        = "EPRT",
  85                         .plen           = sizeof("EPRT") - 1,
  86                         .skip           = ' ',
  87                         .term           = '\r',
  88                         .ftptype        = NF_CT_FTP_EPRT,
  89                         .getnum         = try_eprt,
  90                 },
  91         },
  92         [IP_CT_DIR_REPLY] = {
  93                 {
  94                         .pattern        = "227 ",
  95                         .plen           = sizeof("227 ") - 1,
  96                         .skip           = '(',
  97                         .term           = ')',
  98                         .ftptype        = NF_CT_FTP_PASV,
  99                         .getnum         = try_rfc959,
 100                 },
 101                 {
 102                         .pattern        = "229 ",
 103                         .plen           = sizeof("229 ") - 1,
 104                         .skip           = '(',
 105                         .term           = ')',
 106                         .ftptype        = NF_CT_FTP_EPSV,
 107                         .getnum         = try_epsv_response,
 108                 },
 109         },
 110 };
 111
 112 static int
 113 get_ipv6_addr(const char *src, size_t dlen, struct in6_addr *dst, u_int8_t term)
 114 {
 115         const char *end;
 116         int ret = in6_pton(src, min_t(size_t, dlen, 0xffff), (u8 *)dst, term, &end);
 117         if (ret > 0)
 118                 return (int)(end - src);
 119         return 0;
 120 }
 121
 122 static int try_number(const char *data, size_t dlen, u_int32_t array[],
 123                       int array_size, char sep, char term)
 124 {
 125         u_int32_t i, len;
 126
 127         memset(array, 0, sizeof(array[0])*array_size);
 128
 129         /* Keep data pointing at next char. */
 130         for (i = 0, len = 0; len < dlen && i < array_size; len++, data++) {
 131                 if (*data >= '0' && *data <= '9') {
 132                         array[i] = array[i]*10 + *data - '0';
 133                 }
 134                 else if (*data == sep)
 135                         i++;
 136                 else {
 137                         /* Unexpected character; true if it's the
 138                            terminator and we're finished. */
 139                         if (*data == term && i == array_size - 1)
 140                                 return len;
 141
 142                         DEBUGP("Char %u (got %u nums) `%u' unexpected\n",
 143                                len, i, *data);
 144                         return 0;
 145                 }
 146         }
 147         DEBUGP("Failed to fill %u numbers separated by %c\n", array_size, sep);
 148
 149         return 0;
 150 }
 151
 152 /* Returns 0, or length of numbers: 192,168,1,1,5,6 */
 153 static int try_rfc959(const char *data, size_t dlen,
 154                       struct nf_conntrack_man *cmd, char term)
 155 {
 156         int length;
 157         u_int32_t array[6];
 158
 159         length = try_number(data, dlen, array, 6, ',', term);
 160         if (length == 0)
 161                 return 0;
 162
 163         cmd->u3.ip =  htonl((array[0] << 24) | (array[1] << 16) |
 164                                     (array[2] << 8) | array[3]);
 165         cmd->u.tcp.port = htons((array[4] << 8) | array[5]);
 166         return length;
 167 }
 168
 169 /* Grab port: number up to delimiter */
 170 static int get_port(const char *data, int start, size_t dlen, char delim,
 171                     __be16 *port)
 172 {
 173         u_int16_t tmp_port = 0;
 174         int i;
 175
 176         for (i = start; i < dlen; i++) {
 177                 /* Finished? */
 178                 if (data[i] == delim) {
 179                         if (tmp_port == 0)
 180                                 break;
 181                         *port = htons(tmp_port);
 182                         DEBUGP("get_port: return %d\n", tmp_port);
 183                         return i + 1;
 184                 }
 185                 else if (data[i] >= '0' && data[i] <= '9')
 186                         tmp_port = tmp_port*10 + data[i] - '0';
 187                 else { /* Some other crap */
 188                         DEBUGP("get_port: invalid char.\n");
 189                         break;
 190                 }
 191         }
 192         return 0;
 193 }
 194
 195 /* Returns 0, or length of numbers: |1|132.235.1.2|6275| or |2|3ffe::1|6275| */
 196 static int try_eprt(const char *data, size_t dlen, struct nf_conntrack_man *cmd,
 197                     char term)
 198 {
 199         char delim;
 200         int length;
 201
 202         /* First character is delimiter, then "1" for IPv4 or "2" for IPv6,
 203            then delimiter again. */
 204         if (dlen <= 3) {
 205                 DEBUGP("EPRT: too short\n");
 206                 return 0;
 207         }
 208         delim = data[0];
 209         if (isdigit(delim) || delim < 33 || delim > 126 || data[2] != delim) {
 210                 DEBUGP("try_eprt: invalid delimitter.\n");
 211                 return 0;
 212         }
 213
 214         if ((cmd->l3num == PF_INET && data[1] != '1') ||
 215             (cmd->l3num == PF_INET6 && data[1] != '2')) {
 216                 DEBUGP("EPRT: invalid protocol number.\n");
 217                 return 0;
 218         }
 219
 220         DEBUGP("EPRT: Got %c%c%c\n", delim, data[1], delim);
 221
 222         if (data[1] == '1') {
 223                 u_int32_t array[4];
 224
 225                 /* Now we have IP address. */
 226                 length = try_number(data + 3, dlen - 3, array, 4, '.', delim);
 227                 if (length != 0)
 228                         cmd->u3.ip = htonl((array[0] << 24) | (array[1] << 16)
 229                                            | (array[2] << 8) | array[3]);
 230         } else {
 231                 /* Now we have IPv6 address. */
 232                 length = get_ipv6_addr(data + 3, dlen - 3,
 233                                        (struct in6_addr *)cmd->u3.ip6, delim);
 234         }
 235
 236         if (length == 0)
 237                 return 0;
 238         DEBUGP("EPRT: Got IP address!\n");
 239         /* Start offset includes initial "|1|", and trailing delimiter */
 240         return get_port(data, 3 + length + 1, dlen, delim, &cmd->u.tcp.port);
 241 }
 242
 243 /* Returns 0, or length of numbers: |||6446| */
 244 static int try_epsv_response(const char *data, size_t dlen,
 245                              struct nf_conntrack_man *cmd, char term)
 246 {
 247         char delim;
 248
 249         /* Three delimiters. */
 250         if (dlen <= 3) return 0;
 251         delim = data[0];
 252         if (isdigit(delim) || delim < 33 || delim > 126
 253             || data[1] != delim || data[2] != delim)
 254                 return 0;
 255
 256         return get_port(data, 3, dlen, delim, &cmd->u.tcp.port);
 257 }
 258
 259 /* Return 1 for match, 0 for accept, -1 for partial. */
 260 static int find_pattern(const char *data, size_t dlen,
 261                         const char *pattern, size_t plen,
 262                         char skip, char term,
 263                         unsigned int *numoff,
 264                         unsigned int *numlen,
 265                         struct nf_conntrack_man *cmd,
 266                         int (*getnum)(const char *, size_t,
 267                                       struct nf_conntrack_man *, char))
 268 {
 269         size_t i;
 270
 271         DEBUGP("find_pattern `%s': dlen = %u\n", pattern, dlen);
 272         if (dlen == 0)
 273                 return 0;
 274
 275         if (dlen <= plen) {
 276                 /* Short packet: try for partial? */
 277                 if (strnicmp(data, pattern, dlen) == 0)
 278                         return -1;
 279                 else return 0;
 280         }
 281
 282         if (strnicmp(data, pattern, plen) != 0) {
 283 #if 0
 284                 size_t i;
 285
 286                 DEBUGP("ftp: string mismatch\n");
 287                 for (i = 0; i < plen; i++) {
 288                         DEBUGP("ftp:char %u `%c'(%u) vs `%c'(%u)\n",
 289                                 i, data[i], data[i],
 290                                 pattern[i], pattern[i]);
 291                 }
 292 #endif
 293                 return 0;
 294         }
 295
 296         DEBUGP("Pattern matches!\n");
 297         /* Now we've found the constant string, try to skip
 298            to the 'skip' character */
 299         for (i = plen; data[i] != skip; i++)
 300                 if (i == dlen - 1) return -1;
 301
 302         /* Skip over the last character */
 303         i++;
 304
 305         DEBUGP("Skipped up to `%c'!\n", skip);
 306
 307         *numoff = i;
 308         *numlen = getnum(data + i, dlen - i, cmd, term);
 309         if (!*numlen)
 310                 return -1;
 311
 312         DEBUGP("Match succeeded!\n");
 313         return 1;
 314 }
 315
 316 /* Look up to see if we're just after a \n. */
 317 static int find_nl_seq(u32 seq, const struct nf_ct_ftp_master *info, int dir)
 318 {
 319         unsigned int i;
 320
 321         for (i = 0; i < info->seq_aft_nl_num[dir]; i++)
 322                 if (info->seq_aft_nl[dir][i] == seq)
 323                         return 1;
 324         return 0;
 325 }
 326
 327 /* We don't update if it's older than what we have. */
 328 static void update_nl_seq(u32 nl_seq, struct nf_ct_ftp_master *info, int dir,
 329                           struct sk_buff *skb)
 330 {
 331         unsigned int i, oldest = NUM_SEQ_TO_REMEMBER;
 332
 333         /* Look for oldest: if we find exact match, we're done. */
 334         for (i = 0; i < info->seq_aft_nl_num[dir]; i++) {
 335                 if (info->seq_aft_nl[dir][i] == nl_seq)
 336                         return;
 337
 338                 if (oldest == info->seq_aft_nl_num[dir]
 339                     || before(info->seq_aft_nl[dir][i], oldest))
 340                         oldest = i;
 341         }
 342
 343         if (info->seq_aft_nl_num[dir] < NUM_SEQ_TO_REMEMBER) {
 344                 info->seq_aft_nl[dir][info->seq_aft_nl_num[dir]++] = nl_seq;
 345                 nf_conntrack_event_cache(IPCT_HELPINFO_VOLATILE, skb);
 346         } else if (oldest != NUM_SEQ_TO_REMEMBER) {
 347                 info->seq_aft_nl[dir][oldest] = nl_seq;
 348                 nf_conntrack_event_cache(IPCT_HELPINFO_VOLATILE, skb);
 349         }
 350 }
 351
 352 static int help(struct sk_buff **pskb,
 353                 unsigned int protoff,
 354                 struct nf_conn *ct,
 355                 enum ip_conntrack_info ctinfo)
 356 {
 357         unsigned int dataoff, datalen;
 358         struct tcphdr _tcph, *th;
 359         char *fb_ptr;
 360         int ret;
 361         u32 seq;
 362         int dir = CTINFO2DIR(ctinfo);
 363         unsigned int matchlen, matchoff;
 364         struct nf_ct_ftp_master *ct_ftp_info = &nfct_help(ct)->help.ct_ftp_info;
 365         struct nf_conntrack_expect *exp;
 366         struct nf_conntrack_man cmd = {};
 367         unsigned int i;
 368         int found = 0, ends_in_nl;
 369         typeof(nf_nat_ftp_hook) nf_nat_ftp;
 370
 371         /* Until there's been traffic both ways, don't look in packets. */
 372         if (ctinfo != IP_CT_ESTABLISHED
 373             && ctinfo != IP_CT_ESTABLISHED+IP_CT_IS_REPLY) {
 374                 DEBUGP("ftp: Conntrackinfo = %u\n", ctinfo);
 375                 return NF_ACCEPT;
 376         }
 377
 378         th = skb_header_pointer(*pskb, protoff, sizeof(_tcph), &_tcph);
 379         if (th == NULL)
 380                 return NF_ACCEPT;
 381
 382         dataoff = protoff + th->doff * 4;
 383         /* No data? */
 384         if (dataoff >= (*pskb)->len) {
 385                 DEBUGP("ftp: dataoff(%u) >= skblen(%u)\n", dataoff,
 386                         (*pskb)->len);
 387                 return NF_ACCEPT;
 388         }
 389         datalen = (*pskb)->len - dataoff;
 390
 391         spin_lock_bh(&nf_ftp_lock);
 392         fb_ptr = skb_header_pointer(*pskb, dataoff, datalen, ftp_buffer);
 393         BUG_ON(fb_ptr == NULL);
 394
 395         ends_in_nl = (fb_ptr[datalen - 1] == '\n');
 396         seq = ntohl(th->seq) + datalen;
 397
 398         /* Look up to see if we're just after a \n. */
 399         if (!find_nl_seq(ntohl(th->seq), ct_ftp_info, dir)) {
 400                 /* Now if this ends in \n, update ftp info. */
 401                 DEBUGP("nf_conntrack_ftp_help: wrong seq pos %s(%u) or %s(%u)\n",
 402                        ct_ftp_info->seq_aft_nl_num[dir] > 0 ? "" : "(UNSET)",
 403                        ct_ftp_info->seq_aft_nl[dir][0],
 404                        ct_ftp_info->seq_aft_nl_num[dir] > 1 ? "" : "(UNSET)",
 405                        ct_ftp_info->seq_aft_nl[dir][1]);
 406                 ret = NF_ACCEPT;
 407                 goto out_update_nl;
 408         }
 409
 410         /* Initialize IP/IPv6 addr to expected address (it's not mentioned
 411            in EPSV responses) */
 412         cmd.l3num = ct->tuplehash[dir].tuple.src.l3num;
 413         memcpy(cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all,
 414                sizeof(cmd.u3.all));
 415
 416         for (i = 0; i < ARRAY_SIZE(search[dir]); i++) {
 417                 found = find_pattern(fb_ptr, datalen,
 418                                      search[dir][i].pattern,
 419                                      search[dir][i].plen,
 420                                      search[dir][i].skip,
 421                                      search[dir][i].term,
 422                                      &matchoff, &matchlen,
 423                                      &cmd,
 424                                      search[dir][i].getnum);
 425                 if (found) break;
 426         }
 427         if (found == -1) {
 428                 /* We don't usually drop packets.  After all, this is
 429                    connection tracking, not packet filtering.
 430                    However, it is necessary for accurate tracking in
 431                    this case. */
 432                 if (net_ratelimit())
 433                         printk("conntrack_ftp: partial %s %u+%u\n",
 434                                search[dir][i].pattern,
 435                                ntohl(th->seq), datalen);
 436                 ret = NF_DROP;
 437                 goto out;
 438         } else if (found == 0) { /* No match */
 439                 ret = NF_ACCEPT;
 440                 goto out_update_nl;
 441         }
 442
 443         DEBUGP("conntrack_ftp: match `%.*s' (%u bytes at %u)\n",
 444                (int)matchlen, fb_ptr + matchoff,
 445                matchlen, ntohl(th->seq) + matchoff);
 446
 447         exp = nf_conntrack_expect_alloc(ct);
 448         if (exp == NULL) {
 449                 ret = NF_DROP;
 450                 goto out;
 451         }
 452
 453         /* We refer to the reverse direction ("!dir") tuples here,
 454          * because we're expecting something in the other direction.
 455          * Doesn't matter unless NAT is happening.  */
 456         exp->tuple.dst.u3 = ct->tuplehash[!dir].tuple.dst.u3;
 457
 458         /* Update the ftp info */
 459         if ((cmd.l3num == ct->tuplehash[dir].tuple.src.l3num) &&
 460             memcmp(&cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all,
 461                      sizeof(cmd.u3.all))) {
 462                 /* Enrico Scholz's passive FTP to partially RNAT'd ftp
 463                    server: it really wants us to connect to a
 464                    different IP address.  Simply don't record it for
 465                    NAT. */
 466                 if (cmd.l3num == PF_INET) {
 467                         DEBUGP("conntrack_ftp: NOT RECORDING: " NIPQUAD_FMT " != " NIPQUAD_FMT "\n",
 468                                NIPQUAD(cmd.u3.ip),
 469                                NIPQUAD(ct->tuplehash[dir].tuple.src.u3.ip));
 470                 } else {
 471                         DEBUGP("conntrack_ftp: NOT RECORDING: " NIP6_FMT " != " NIP6_FMT "\n",
 472                                NIP6(*((struct in6_addr *)cmd.u3.ip6)),
 473                                NIP6(*((struct in6_addr *)ct->tuplehash[dir]
 474                                                         .tuple.src.u3.ip6)));
 475                 }
 476
 477                 /* Thanks to Cristiano Lincoln Mattos
 478                    <lincoln@cesar.org.br> for reporting this potential
 479                    problem (DMZ machines opening holes to internal
 480                    networks, or the packet filter itself). */
 481                 if (!loose) {
 482                         ret = NF_ACCEPT;
 483                         goto out_put_expect;
 484                 }
 485                 memcpy(&exp->tuple.dst.u3, &cmd.u3.all,
 486                        sizeof(exp->tuple.dst.u3));
 487         }
 488
 489         exp->tuple.src.u3 = ct->tuplehash[!dir].tuple.src.u3;
 490         exp->tuple.src.l3num = cmd.l3num;
 491         exp->tuple.src.u.tcp.port = 0;
 492         exp->tuple.dst.u.tcp.port = cmd.u.tcp.port;
 493         exp->tuple.dst.protonum = IPPROTO_TCP;
 494
 495         exp->mask = (struct nf_conntrack_tuple)
 496                     { .src = { .l3num = 0xFFFF,
 497                                .u = { .tcp = { 0 }},
 498                              },
 499                       .dst = { .protonum = 0xFF,
 500                                .u = { .tcp = { __constant_htons(0xFFFF) }},
 501                              },
 502                     };
 503         if (cmd.l3num == PF_INET) {
 504                 exp->mask.src.u3.ip = htonl(0xFFFFFFFF);
 505                 exp->mask.dst.u3.ip = htonl(0xFFFFFFFF);
 506         } else {
 507                 memset(exp->mask.src.u3.ip6, 0xFF,
 508                        sizeof(exp->mask.src.u3.ip6));
 509                 memset(exp->mask.dst.u3.ip6, 0xFF,
 510                        sizeof(exp->mask.src.u3.ip6));
 511         }
 512
 513         exp->expectfn = NULL;
 514         exp->helper = NULL;
 515         exp->flags = 0;
 516
 517         /* Now, NAT might want to mangle the packet, and register the
 518          * (possibly changed) expectation itself. */
 519         nf_nat_ftp = rcu_dereference(nf_nat_ftp_hook);
 520         if (nf_nat_ftp && ct->status & IPS_NAT_MASK)
 521                 ret = nf_nat_ftp(pskb, ctinfo, search[dir][i].ftptype,
 522                                  matchoff, matchlen, exp, &seq);
 523         else {
 524                 /* Can't expect this?  Best to drop packet now. */
 525                 if (nf_conntrack_expect_related(exp) != 0)
 526                         ret = NF_DROP;
 527                 else
 528                         ret = NF_ACCEPT;
 529         }
 530
 531 out_put_expect:
 532         nf_conntrack_expect_put(exp);
 533
 534 out_update_nl:
 535         /* Now if this ends in \n, update ftp info.  Seq may have been
 536          * adjusted by NAT code. */
 537         if (ends_in_nl)
 538                 update_nl_seq(seq, ct_ftp_info, dir, *pskb);
 539  out:
 540         spin_unlock_bh(&nf_ftp_lock);
 541         return ret;
 542 }
 543
 544 static struct nf_conntrack_helper ftp[MAX_PORTS][2];
 545 static char ftp_names[MAX_PORTS][2][sizeof("ftp-65535")];
 546
 547 /* don't make this __exit, since it's called from __init ! */
 548 static void nf_conntrack_ftp_fini(void)
 549 {
 550         int i, j;
 551         for (i = 0; i < ports_c; i++) {
 552                 for (j = 0; j < 2; j++) {
 553                         if (ftp[i][j].me == NULL)
 554                                 continue;
 555
 556                         DEBUGP("nf_ct_ftp: unregistering helper for pf: %d "
 557                                "port: %d\n",
 558                                 ftp[i][j].tuple.src.l3num, ports[i]);
 559                         nf_conntrack_helper_unregister(&ftp[i][j]);
 560                 }
 561         }
 562
 563         kfree(ftp_buffer);
 564 }
 565
 566 static int __init nf_conntrack_ftp_init(void)
 567 {
 568         int i, j = -1, ret = 0;
 569         char *tmpname;
 570
 571         ftp_buffer = kmalloc(65536, GFP_KERNEL);
 572         if (!ftp_buffer)
 573                 return -ENOMEM;
 574
 575         if (ports_c == 0)
 576                 ports[ports_c++] = FTP_PORT;
 577
 578         /* FIXME should be configurable whether IPv4 and IPv6 FTP connections
 579                  are tracked or not - YK */
 580         for (i = 0; i < ports_c; i++) {
 581                 ftp[i][0].tuple.src.l3num = PF_INET;
 582                 ftp[i][1].tuple.src.l3num = PF_INET6;
 583                 for (j = 0; j < 2; j++) {
 584                         ftp[i][j].tuple.src.u.tcp.port = htons(ports[i]);
 585                         ftp[i][j].tuple.dst.protonum = IPPROTO_TCP;
 586                         ftp[i][j].mask.src.l3num = 0xFFFF;
 587                         ftp[i][j].mask.src.u.tcp.port = htons(0xFFFF);
 588                         ftp[i][j].mask.dst.protonum = 0xFF;
 589                         ftp[i][j].max_expected = 1;
 590                         ftp[i][j].timeout = 5 * 60;     /* 5 Minutes */
 591                         ftp[i][j].me = THIS_MODULE;
 592                         ftp[i][j].help = help;
 593                         tmpname = &ftp_names[i][j][0];
 594                         if (ports[i] == FTP_PORT)
 595                                 sprintf(tmpname, "ftp");
 596                         else
 597                                 sprintf(tmpname, "ftp-%d", ports[i]);
 598                         ftp[i][j].name = tmpname;
 599
 600                         DEBUGP("nf_ct_ftp: registering helper for pf: %d "
 601                                "port: %d\n",
 602                                 ftp[i][j].tuple.src.l3num, ports[i]);
 603                         ret = nf_conntrack_helper_register(&ftp[i][j]);
 604                         if (ret) {
 605                                 printk("nf_ct_ftp: failed to register helper "
 606                                        " for pf: %d port: %d\n",
 607                                         ftp[i][j].tuple.src.l3num, ports[i]);
 608                                 nf_conntrack_ftp_fini();
 609                                 return ret;
 610                         }
 611                 }
 612         }
 613
 614         return 0;
 615 }
 616
 617 module_init(nf_conntrack_ftp_init);
 618 module_exit(nf_conntrack_ftp_fini);