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  * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
  12  *      - enable working with Layer 3 protocol independent connection tracking.
  13  *      - track EPRT and EPSV commands with IPv6 address.
  14  *
  15  * Derived from net/ipv4/netfilter/ip_conntrack_ftp.c
  16  */
  17
  18 #include <linux/module.h>
  19 #include <linux/moduleparam.h>
  20 #include <linux/netfilter.h>
  21 #include <linux/ip.h>
  22 #include <linux/ipv6.h>
  23 #include <linux/ctype.h>
  24 #include <linux/inet.h>
  25 #include <net/checksum.h>
  26 #include <net/tcp.h>
  27
  28 #include <net/netfilter/nf_conntrack.h>
  29 #include <net/netfilter/nf_conntrack_expect.h>
  30 #include <net/netfilter/nf_conntrack_ecache.h>
  31 #include <net/netfilter/nf_conntrack_helper.h>
  32 #include <linux/netfilter/nf_conntrack_ftp.h>
  33
  34 MODULE_LICENSE("GPL");
  35 MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
  36 MODULE_DESCRIPTION("ftp connection tracking helper");
  37
  38 /* This is slow, but it's simple. --RR */
  39 static char *ftp_buffer;
  40
  41 static DEFINE_SPINLOCK(nf_ftp_lock);
  42
  43 #define MAX_PORTS 8
  44 static u_int16_t ports[MAX_PORTS];
  45 static unsigned int ports_c;
  46 module_param_array(ports, ushort, &ports_c, 0400);
  47
  48 static int loose;
  49 module_param(loose, bool, 0600);
  50
  51 unsigned int (*nf_nat_ftp_hook)(struct sk_buff **pskb,
  52                                 enum ip_conntrack_info ctinfo,
  53                                 enum ip_ct_ftp_type type,
  54                                 unsigned int matchoff,
  55                                 unsigned int matchlen,
  56                                 struct nf_conntrack_expect *exp,
  57                                 u32 *seq);
  58 EXPORT_SYMBOL_GPL(nf_nat_ftp_hook);
  59
  60 #if 0
  61 #define DEBUGP printk
  62 #else
  63 #define DEBUGP(format, args...)
  64 #endif
  65
  66 static int try_rfc959(const char *, size_t, struct nf_conntrack_man *, char);
  67 static int try_eprt(const char *, size_t, struct nf_conntrack_man *, char);
  68 static int try_epsv_response(const char *, size_t, struct nf_conntrack_man *,
  69                              char);
  70
  71 static struct ftp_search {
  72         const char *pattern;
  73         size_t plen;
  74         char skip;
  75         char term;
  76         enum ip_ct_ftp_type ftptype;
  77         int (*getnum)(const char *, size_t, struct nf_conntrack_man *, char);
  78 } search[IP_CT_DIR_MAX][2] = {
  79         [IP_CT_DIR_ORIGINAL] = {
  80                 {
  81                         .pattern        = "PORT",
  82                         .plen           = sizeof("PORT") - 1,
  83                         .skip           = ' ',
  84                         .term           = '\r',
  85                         .ftptype        = IP_CT_FTP_PORT,
  86                         .getnum         = try_rfc959,
  87                 },
  88                 {
  89                         .pattern        = "EPRT",
  90                         .plen           = sizeof("EPRT") - 1,
  91                         .skip           = ' ',
  92                         .term           = '\r',
  93                         .ftptype        = IP_CT_FTP_EPRT,
  94                         .getnum         = try_eprt,
  95                 },
  96         },
  97         [IP_CT_DIR_REPLY] = {
  98                 {
  99                         .pattern        = "227 ",
 100                         .plen           = sizeof("227 ") - 1,
 101                         .skip           = '(',
 102                         .term           = ')',
 103                         .ftptype        = IP_CT_FTP_PASV,
 104                         .getnum         = try_rfc959,
 105                 },
 106                 {
 107                         .pattern        = "229 ",
 108                         .plen           = sizeof("229 ") - 1,
 109                         .skip           = '(',
 110                         .term           = ')',
 111                         .ftptype        = IP_CT_FTP_EPSV,
 112                         .getnum         = try_epsv_response,
 113                 },
 114         },
 115 };
 116
 117 static int
 118 get_ipv6_addr(const char *src, size_t dlen, struct in6_addr *dst, u_int8_t term)
 119 {
 120         const char *end;
 121         int ret = in6_pton(src, min_t(size_t, dlen, 0xffff), (u8 *)dst, term, &end);
 122         if (ret > 0)
 123                 return (int)(end - src);
 124         return 0;
 125 }
 126
 127 static int try_number(const char *data, size_t dlen, u_int32_t array[],
 128                       int array_size, char sep, char term)
 129 {
 130         u_int32_t i, len;
 131
 132         memset(array, 0, sizeof(array[0])*array_size);
 133
 134         /* Keep data pointing at next char. */
 135         for (i = 0, len = 0; len < dlen && i < array_size; len++, data++) {
 136                 if (*data >= '0' && *data <= '9') {
 137                         array[i] = array[i]*10 + *data - '0';
 138                 }
 139                 else if (*data == sep)
 140                         i++;
 141                 else {
 142                         /* Unexpected character; true if it's the
 143                            terminator and we're finished. */
 144                         if (*data == term && i == array_size - 1)
 145                                 return len;
 146
 147                         DEBUGP("Char %u (got %u nums) `%u' unexpected\n",
 148                                len, i, *data);
 149                         return 0;
 150                 }
 151         }
 152         DEBUGP("Failed to fill %u numbers separated by %c\n", array_size, sep);
 153
 154         return 0;
 155 }
 156
 157 /* Returns 0, or length of numbers: 192,168,1,1,5,6 */
 158 static int try_rfc959(const char *data, size_t dlen,
 159                       struct nf_conntrack_man *cmd, char term)
 160 {
 161         int length;
 162         u_int32_t array[6];
 163
 164         length = try_number(data, dlen, array, 6, ',', term);
 165         if (length == 0)
 166                 return 0;
 167
 168         cmd->u3.ip =  htonl((array[0] << 24) | (array[1] << 16) |
 169                                     (array[2] << 8) | array[3]);
 170         cmd->u.tcp.port = htons((array[4] << 8) | array[5]);
 171         return length;
 172 }
 173
 174 /* Grab port: number up to delimiter */
 175 static int get_port(const char *data, int start, size_t dlen, char delim,
 176                     u_int16_t *port)
 177 {
 178         u_int16_t tmp_port = 0;
 179         int i;
 180
 181         for (i = start; i < dlen; i++) {
 182                 /* Finished? */
 183                 if (data[i] == delim) {
 184                         if (tmp_port == 0)
 185                                 break;
 186                         *port = htons(tmp_port);
 187                         DEBUGP("get_port: return %d\n", tmp_port);
 188                         return i + 1;
 189                 }
 190                 else if (data[i] >= '0' && data[i] <= '9')
 191                         tmp_port = tmp_port*10 + data[i] - '0';
 192                 else { /* Some other crap */
 193                         DEBUGP("get_port: invalid char.\n");
 194                         break;
 195                 }
 196         }
 197         return 0;
 198 }
 199
 200 /* Returns 0, or length of numbers: |1|132.235.1.2|6275| or |2|3ffe::1|6275| */
 201 static int try_eprt(const char *data, size_t dlen, struct nf_conntrack_man *cmd,
 202                     char term)
 203 {
 204         char delim;
 205         int length;
 206
 207         /* First character is delimiter, then "1" for IPv4 or "2" for IPv6,
 208            then delimiter again. */
 209         if (dlen <= 3) {
 210                 DEBUGP("EPRT: too short\n");
 211                 return 0;
 212         }
 213         delim = data[0];
 214         if (isdigit(delim) || delim < 33 || delim > 126 || data[2] != delim) {
 215                 DEBUGP("try_eprt: invalid delimitter.\n");
 216                 return 0;
 217         }
 218
 219         if ((cmd->l3num == PF_INET && data[1] != '1') ||
 220             (cmd->l3num == PF_INET6 && data[1] != '2')) {
 221                 DEBUGP("EPRT: invalid protocol number.\n");
 222                 return 0;
 223         }
 224
 225         DEBUGP("EPRT: Got %c%c%c\n", delim, data[1], delim);
 226
 227         if (data[1] == '1') {
 228                 u_int32_t array[4];
 229
 230                 /* Now we have IP address. */
 231                 length = try_number(data + 3, dlen - 3, array, 4, '.', delim);
 232                 if (length != 0)
 233                         cmd->u3.ip = htonl((array[0] << 24) | (array[1] << 16)
 234                                            | (array[2] << 8) | array[3]);
 235         } else {
 236                 /* Now we have IPv6 address. */
 237                 length = get_ipv6_addr(data + 3, dlen - 3,
 238                                        (struct in6_addr *)cmd->u3.ip6, delim);
 239         }
 240
 241         if (length == 0)
 242                 return 0;
 243         DEBUGP("EPRT: Got IP address!\n");
 244         /* Start offset includes initial "|1|", and trailing delimiter */
 245         return get_port(data, 3 + length + 1, dlen, delim, &cmd->u.tcp.port);
 246 }
 247
 248 /* Returns 0, or length of numbers: |||6446| */
 249 static int try_epsv_response(const char *data, size_t dlen,
 250                              struct nf_conntrack_man *cmd, char term)
 251 {
 252         char delim;
 253
 254         /* Three delimiters. */
 255         if (dlen <= 3) return 0;
 256         delim = data[0];
 257         if (isdigit(delim) || delim < 33 || delim > 126
 258             || data[1] != delim || data[2] != delim)
 259                 return 0;
 260
 261         return get_port(data, 3, dlen, delim, &cmd->u.tcp.port);
 262 }
 263
 264 /* Return 1 for match, 0 for accept, -1 for partial. */
 265 static int find_pattern(const char *data, size_t dlen,
 266                         const char *pattern, size_t plen,
 267                         char skip, char term,
 268                         unsigned int *numoff,
 269                         unsigned int *numlen,
 270                         struct nf_conntrack_man *cmd,
 271                         int (*getnum)(const char *, size_t,
 272                                       struct nf_conntrack_man *, char))
 273 {
 274         size_t i;
 275
 276         DEBUGP("find_pattern `%s': dlen = %u\n", pattern, dlen);
 277         if (dlen == 0)
 278                 return 0;
 279
 280         if (dlen <= plen) {
 281                 /* Short packet: try for partial? */
 282                 if (strnicmp(data, pattern, dlen) == 0)
 283                         return -1;
 284                 else return 0;
 285         }
 286
 287         if (strnicmp(data, pattern, plen) != 0) {
 288 #if 0
 289                 size_t i;
 290
 291                 DEBUGP("ftp: string mismatch\n");
 292                 for (i = 0; i < plen; i++) {
 293                         DEBUGP("ftp:char %u `%c'(%u) vs `%c'(%u)\n",
 294                                 i, data[i], data[i],
 295                                 pattern[i], pattern[i]);
 296                 }
 297 #endif
 298                 return 0;
 299         }
 300
 301         DEBUGP("Pattern matches!\n");
 302         /* Now we've found the constant string, try to skip
 303            to the 'skip' character */
 304         for (i = plen; data[i] != skip; i++)
 305                 if (i == dlen - 1) return -1;
 306
 307         /* Skip over the last character */
 308         i++;
 309
 310         DEBUGP("Skipped up to `%c'!\n", skip);
 311
 312         *numoff = i;
 313         *numlen = getnum(data + i, dlen - i, cmd, term);
 314         if (!*numlen)
 315                 return -1;
 316
 317         DEBUGP("Match succeeded!\n");
 318         return 1;
 319 }
 320
 321 /* Look up to see if we're just after a \n. */
 322 static int find_nl_seq(u32 seq, const struct ip_ct_ftp_master *info, int dir)
 323 {
 324         unsigned int i;
 325
 326         for (i = 0; i < info->seq_aft_nl_num[dir]; i++)
 327                 if (info->seq_aft_nl[dir][i] == seq)
 328                         return 1;
 329         return 0;
 330 }
 331
 332 /* We don't update if it's older than what we have. */
 333 static void update_nl_seq(u32 nl_seq, struct ip_ct_ftp_master *info, int dir,
 334                           struct sk_buff *skb)
 335 {
 336         unsigned int i, oldest = NUM_SEQ_TO_REMEMBER;
 337
 338         /* Look for oldest: if we find exact match, we're done. */
 339         for (i = 0; i < info->seq_aft_nl_num[dir]; i++) {
 340                 if (info->seq_aft_nl[dir][i] == nl_seq)
 341                         return;
 342
 343                 if (oldest == info->seq_aft_nl_num[dir]
 344                     || before(info->seq_aft_nl[dir][i], oldest))
 345                         oldest = i;
 346         }
 347
 348         if (info->seq_aft_nl_num[dir] < NUM_SEQ_TO_REMEMBER) {
 349                 info->seq_aft_nl[dir][info->seq_aft_nl_num[dir]++] = nl_seq;
 350                 nf_conntrack_event_cache(IPCT_HELPINFO_VOLATILE, skb);
 351         } else if (oldest != NUM_SEQ_TO_REMEMBER) {
 352                 info->seq_aft_nl[dir][oldest] = nl_seq;
 353                 nf_conntrack_event_cache(IPCT_HELPINFO_VOLATILE, skb);
 354         }
 355 }
 356
 357 static int help(struct sk_buff **pskb,
 358                 unsigned int protoff,
 359                 struct nf_conn *ct,
 360                 enum ip_conntrack_info ctinfo)
 361 {
 362         unsigned int dataoff, datalen;
 363         struct tcphdr _tcph, *th;
 364         char *fb_ptr;
 365         int ret;
 366         u32 seq;
 367         int dir = CTINFO2DIR(ctinfo);
 368         unsigned int matchlen, matchoff;
 369         struct ip_ct_ftp_master *ct_ftp_info = &nfct_help(ct)->help.ct_ftp_info;
 370         struct nf_conntrack_expect *exp;
 371         struct nf_conntrack_man cmd = {};
 372
 373         unsigned int i;
 374         int found = 0, ends_in_nl;
 375
 376         /* Until there's been traffic both ways, don't look in packets. */
 377         if (ctinfo != IP_CT_ESTABLISHED
 378             && ctinfo != IP_CT_ESTABLISHED+IP_CT_IS_REPLY) {
 379                 DEBUGP("ftp: Conntrackinfo = %u\n", ctinfo);
 380                 return NF_ACCEPT;
 381         }
 382
 383         th = skb_header_pointer(*pskb, protoff, sizeof(_tcph), &_tcph);
 384         if (th == NULL)
 385                 return NF_ACCEPT;
 386
 387         dataoff = protoff + th->doff * 4;
 388         /* No data? */
 389         if (dataoff >= (*pskb)->len) {
 390                 DEBUGP("ftp: dataoff(%u) >= skblen(%u)\n", dataoff,
 391                         (*pskb)->len);
 392                 return NF_ACCEPT;
 393         }
 394         datalen = (*pskb)->len - dataoff;
 395
 396         spin_lock_bh(&nf_ftp_lock);
 397         fb_ptr = skb_header_pointer(*pskb, dataoff, datalen, ftp_buffer);
 398         BUG_ON(fb_ptr == NULL);
 399
 400         ends_in_nl = (fb_ptr[datalen - 1] == '\n');
 401         seq = ntohl(th->seq) + datalen;
 402
 403         /* Look up to see if we're just after a \n. */
 404         if (!find_nl_seq(ntohl(th->seq), ct_ftp_info, dir)) {
 405                 /* Now if this ends in \n, update ftp info. */
 406                 DEBUGP("nf_conntrack_ftp_help: wrong seq pos %s(%u) or %s(%u)\n",
 407                        ct_ftp_info->seq_aft_nl_num[dir] > 0 ? "" : "(UNSET)",
 408                        ct_ftp_info->seq_aft_nl[dir][0],
 409                        ct_ftp_info->seq_aft_nl_num[dir] > 1 ? "" : "(UNSET)",
 410                        ct_ftp_info->seq_aft_nl[dir][1]);
 411                 ret = NF_ACCEPT;
 412                 goto out_update_nl;
 413         }
 414
 415         /* Initialize IP/IPv6 addr to expected address (it's not mentioned
 416            in EPSV responses) */
 417         cmd.l3num = ct->tuplehash[dir].tuple.src.l3num;
 418         memcpy(cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all,
 419                sizeof(cmd.u3.all));
 420
 421         for (i = 0; i < ARRAY_SIZE(search[dir]); i++) {
 422                 found = find_pattern(fb_ptr, datalen,
 423                                      search[dir][i].pattern,
 424                                      search[dir][i].plen,
 425                                      search[dir][i].skip,
 426                                      search[dir][i].term,
 427                                      &matchoff, &matchlen,
 428                                      &cmd,
 429                                      search[dir][i].getnum);
 430                 if (found) break;
 431         }
 432         if (found == -1) {
 433                 /* We don't usually drop packets.  After all, this is
 434                    connection tracking, not packet filtering.
 435                    However, it is necessary for accurate tracking in
 436                    this case. */
 437                 if (net_ratelimit())
 438                         printk("conntrack_ftp: partial %s %u+%u\n",
 439                                search[dir][i].pattern,
 440                                ntohl(th->seq), datalen);
 441                 ret = NF_DROP;
 442                 goto out;
 443         } else if (found == 0) { /* No match */
 444                 ret = NF_ACCEPT;
 445                 goto out_update_nl;
 446         }
 447
 448         DEBUGP("conntrack_ftp: match `%.*s' (%u bytes at %u)\n",
 449                (int)matchlen, fb_ptr + matchoff,
 450                matchlen, ntohl(th->seq) + matchoff);
 451
 452         exp = nf_conntrack_expect_alloc(ct);
 453         if (exp == NULL) {
 454                 ret = NF_DROP;
 455                 goto out;
 456         }
 457
 458         /* We refer to the reverse direction ("!dir") tuples here,
 459          * because we're expecting something in the other direction.
 460          * Doesn't matter unless NAT is happening.  */
 461         exp->tuple.dst.u3 = ct->tuplehash[!dir].tuple.dst.u3;
 462
 463         /* Update the ftp info */
 464         if ((cmd.l3num == ct->tuplehash[dir].tuple.src.l3num) &&
 465             memcmp(&cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all,
 466                      sizeof(cmd.u3.all))) {
 467                 /* Enrico Scholz's passive FTP to partially RNAT'd ftp
 468                    server: it really wants us to connect to a
 469                    different IP address.  Simply don't record it for
 470                    NAT. */
 471                 if (cmd.l3num == PF_INET) {
 472                         DEBUGP("conntrack_ftp: NOT RECORDING: " NIPQUAD_FMT " != " NIPQUAD_FMT "\n",
 473                                NIPQUAD(cmd.u3.ip),
 474                                NIPQUAD(ct->tuplehash[dir].tuple.src.u3.ip));
 475                 } else {
 476                         DEBUGP("conntrack_ftp: NOT RECORDING: " NIP6_FMT " != " NIP6_FMT "\n",
 477                                NIP6(*((struct in6_addr *)cmd.u3.ip6)),
 478                                NIP6(*((struct in6_addr *)ct->tuplehash[dir]
 479                                                         .tuple.src.u3.ip6)));
 480                 }
 481
 482                 /* Thanks to Cristiano Lincoln Mattos
 483                    <lincoln@cesar.org.br> for reporting this potential
 484                    problem (DMZ machines opening holes to internal
 485                    networks, or the packet filter itself). */
 486                 if (!loose) {
 487                         ret = NF_ACCEPT;
 488                         goto out_put_expect;
 489                 }
 490                 memcpy(&exp->tuple.dst.u3, &cmd.u3.all,
 491                        sizeof(exp->tuple.dst.u3));
 492         }
 493
 494         exp->tuple.src.u3 = ct->tuplehash[!dir].tuple.src.u3;
 495         exp->tuple.src.l3num = cmd.l3num;
 496         exp->tuple.src.u.tcp.port = 0;
 497         exp->tuple.dst.u.tcp.port = cmd.u.tcp.port;
 498         exp->tuple.dst.protonum = IPPROTO_TCP;
 499
 500         exp->mask = (struct nf_conntrack_tuple)
 501                     { .src = { .l3num = 0xFFFF,
 502                                .u = { .tcp = { 0 }},
 503                              },
 504                       .dst = { .protonum = 0xFF,
 505                                .u = { .tcp = { 0xFFFF }},
 506                              },
 507                     };
 508         if (cmd.l3num == PF_INET) {
 509                 exp->mask.src.u3.ip = 0xFFFFFFFF;
 510                 exp->mask.dst.u3.ip = 0xFFFFFFFF;
 511         } else {
 512                 memset(exp->mask.src.u3.ip6, 0xFF,
 513                        sizeof(exp->mask.src.u3.ip6));
 514                 memset(exp->mask.dst.u3.ip6, 0xFF,
 515                        sizeof(exp->mask.src.u3.ip6));
 516         }
 517
 518         exp->expectfn = NULL;
 519         exp->flags = 0;
 520
 521         /* Now, NAT might want to mangle the packet, and register the
 522          * (possibly changed) expectation itself. */
 523         if (nf_nat_ftp_hook)
 524                 ret = nf_nat_ftp_hook(pskb, ctinfo, search[dir][i].ftptype,
 525                                       matchoff, matchlen, exp, &seq);
 526         else {
 527                 /* Can't expect this?  Best to drop packet now. */
 528                 if (nf_conntrack_expect_related(exp) != 0)
 529                         ret = NF_DROP;
 530                 else
 531                         ret = NF_ACCEPT;
 532         }
 533
 534 out_put_expect:
 535         nf_conntrack_expect_put(exp);
 536
 537 out_update_nl:
 538         /* Now if this ends in \n, update ftp info.  Seq may have been
 539          * adjusted by NAT code. */
 540         if (ends_in_nl)
 541                 update_nl_seq(seq, ct_ftp_info, dir, *pskb);
 542  out:
 543         spin_unlock_bh(&nf_ftp_lock);
 544         return ret;
 545 }
 546
 547 static struct nf_conntrack_helper ftp[MAX_PORTS][2];
 548 static char ftp_names[MAX_PORTS][2][sizeof("ftp-65535")];
 549
 550 /* don't make this __exit, since it's called from __init ! */
 551 static void nf_conntrack_ftp_fini(void)
 552 {
 553         int i, j;
 554         for (i = 0; i < ports_c; i++) {
 555                 for (j = 0; j < 2; j++) {
 556                         if (ftp[i][j].me == NULL)
 557                                 continue;
 558
 559                         DEBUGP("nf_ct_ftp: unregistering helper for pf: %d "
 560                                "port: %d\n",
 561                                 ftp[i][j].tuple.src.l3num, ports[i]);
 562                         nf_conntrack_helper_unregister(&ftp[i][j]);
 563                 }
 564         }
 565
 566         kfree(ftp_buffer);
 567 }
 568
 569 static int __init nf_conntrack_ftp_init(void)
 570 {
 571         int i, j = -1, ret = 0;
 572         char *tmpname;
 573
 574         ftp_buffer = kmalloc(65536, GFP_KERNEL);
 575         if (!ftp_buffer)
 576                 return -ENOMEM;
 577
 578         if (ports_c == 0)
 579                 ports[ports_c++] = FTP_PORT;
 580
 581         /* FIXME should be configurable whether IPv4 and IPv6 FTP connections
 582                  are tracked or not - YK */
 583         for (i = 0; i < ports_c; i++) {
 584                 ftp[i][0].tuple.src.l3num = PF_INET;
 585                 ftp[i][1].tuple.src.l3num = PF_INET6;
 586                 for (j = 0; j < 2; j++) {
 587                         ftp[i][j].tuple.src.u.tcp.port = htons(ports[i]);
 588                         ftp[i][j].tuple.dst.protonum = IPPROTO_TCP;
 589                         ftp[i][j].mask.src.u.tcp.port = 0xFFFF;
 590                         ftp[i][j].mask.dst.protonum = 0xFF;
 591                         ftp[i][j].max_expected = 1;
 592                         ftp[i][j].timeout = 5 * 60;     /* 5 Minutes */
 593                         ftp[i][j].me = THIS_MODULE;
 594                         ftp[i][j].help = help;
 595                         tmpname = &ftp_names[i][j][0];
 596                         if (ports[i] == FTP_PORT)
 597                                 sprintf(tmpname, "ftp");
 598                         else
 599                                 sprintf(tmpname, "ftp-%d", ports[i]);
 600                         ftp[i][j].name = tmpname;
 601
 602                         DEBUGP("nf_ct_ftp: registering helper for pf: %d "
 603                                "port: %d\n",
 604                                 ftp[i][j].tuple.src.l3num, ports[i]);
 605                         ret = nf_conntrack_helper_register(&ftp[i][j]);
 606                         if (ret) {
 607                                 printk("nf_ct_ftp: failed to register helper "
 608                                        " for pf: %d port: %d\n",
 609                                         ftp[i][j].tuple.src.l3num, ports[i]);
 610                                 nf_conntrack_ftp_fini();
 611                                 return ret;
 612                         }
 613                 }
 614         }
 615
 616         return 0;
 617 }
 618
 619 module_init(nf_conntrack_ftp_init);
 620 module_exit(nf_conntrack_ftp_fini);