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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  *
   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 MODULE_ALIAS("ip_conntrack_ftp");
  38
  39 /* This is slow, but it's simple. --RR */
  40 static char *ftp_buffer;
  41
  42 static DEFINE_SPINLOCK(nf_ftp_lock);
  43
  44 #define MAX_PORTS 8
  45 static u_int16_t ports[MAX_PORTS];
  46 static unsigned int ports_c;
  47 module_param_array(ports, ushort, &ports_c, 0400);
  48
  49 static int loose;
  50 module_param(loose, bool, 0600);
  51
  52 unsigned int (*nf_nat_ftp_hook)(struct sk_buff **pskb,
  53                                 enum ip_conntrack_info ctinfo,
  54                                 enum nf_ct_ftp_type type,
  55                                 unsigned int matchoff,
  56                                 unsigned int matchlen,
  57                                 struct nf_conntrack_expect *exp,
  58                                 u32 *seq);
  59 EXPORT_SYMBOL_GPL(nf_nat_ftp_hook);
  60
  61 #if 0
  62 #define DEBUGP printk
  63 #else
  64 #define DEBUGP(format, args...)
  65 #endif
  66
  67 static int try_rfc959(const char *, size_t, struct nf_conntrack_man *, char);
  68 static int try_eprt(const char *, size_t, struct nf_conntrack_man *, char);
  69 static int try_epsv_response(const char *, size_t, struct nf_conntrack_man *,
  70                              char);
  71
  72 static struct ftp_search {
  73         const char *pattern;
  74         size_t plen;
  75         char skip;
  76         char term;
  77         enum nf_ct_ftp_type ftptype;
  78         int (*getnum)(const char *, size_t, struct nf_conntrack_man *, char);
  79 } search[IP_CT_DIR_MAX][2] = {
  80         [IP_CT_DIR_ORIGINAL] = {
  81                 {
  82                         .pattern        = "PORT",
  83                         .plen           = sizeof("PORT") - 1,
  84                         .skip           = ' ',
  85                         .term           = '\r',
  86                         .ftptype        = NF_CT_FTP_PORT,
  87                         .getnum         = try_rfc959,
  88                 },
  89                 {
  90                         .pattern        = "EPRT",
  91                         .plen           = sizeof("EPRT") - 1,
  92                         .skip           = ' ',
  93                         .term           = '\r',
  94                         .ftptype        = NF_CT_FTP_EPRT,
  95                         .getnum         = try_eprt,
  96                 },
  97         },
  98         [IP_CT_DIR_REPLY] = {
  99                 {
 100                         .pattern        = "227 ",
 101                         .plen           = sizeof("227 ") - 1,
 102                         .skip           = '(',
 103                         .term           = ')',
 104                         .ftptype        = NF_CT_FTP_PASV,
 105                         .getnum         = try_rfc959,
 106                 },
 107                 {
 108                         .pattern        = "229 ",
 109                         .plen           = sizeof("229 ") - 1,
 110                         .skip           = '(',
 111                         .term           = ')',
 112                         .ftptype        = NF_CT_FTP_EPSV,
 113                         .getnum         = try_epsv_response,
 114                 },
 115         },
 116 };
 117
 118 static int
 119 get_ipv6_addr(const char *src, size_t dlen, struct in6_addr *dst, u_int8_t term)
 120 {
 121         const char *end;
 122         int ret = in6_pton(src, min_t(size_t, dlen, 0xffff), (u8 *)dst, term, &end);
 123         if (ret > 0)
 124                 return (int)(end - src);
 125         return 0;
 126 }
 127
 128 static int try_number(const char *data, size_t dlen, u_int32_t array[],
 129                       int array_size, char sep, char term)
 130 {
 131         u_int32_t i, len;
 132
 133         memset(array, 0, sizeof(array[0])*array_size);
 134
 135         /* Keep data pointing at next char. */
 136         for (i = 0, len = 0; len < dlen && i < array_size; len++, data++) {
 137                 if (*data >= '0' && *data <= '9') {
 138                         array[i] = array[i]*10 + *data - '0';
 139                 }
 140                 else if (*data == sep)
 141                         i++;
 142                 else {
 143                         /* Unexpected character; true if it's the
 144                            terminator and we're finished. */
 145                         if (*data == term && i == array_size - 1)
 146                                 return len;
 147
 148                         DEBUGP("Char %u (got %u nums) `%u' unexpected\n",
 149                                len, i, *data);
 150                         return 0;
 151                 }
 152         }
 153         DEBUGP("Failed to fill %u numbers separated by %c\n", array_size, sep);
 154
 155         return 0;
 156 }
 157
 158 /* Returns 0, or length of numbers: 192,168,1,1,5,6 */
 159 static int try_rfc959(const char *data, size_t dlen,
 160                       struct nf_conntrack_man *cmd, char term)
 161 {
 162         int length;
 163         u_int32_t array[6];
 164
 165         length = try_number(data, dlen, array, 6, ',', term);
 166         if (length == 0)
 167                 return 0;
 168
 169         cmd->u3.ip =  htonl((array[0] << 24) | (array[1] << 16) |
 170                                     (array[2] << 8) | array[3]);
 171         cmd->u.tcp.port = htons((array[4] << 8) | array[5]);
 172         return length;
 173 }
 174
 175 /* Grab port: number up to delimiter */
 176 static int get_port(const char *data, int start, size_t dlen, char delim,
 177                     __be16 *port)
 178 {
 179         u_int16_t tmp_port = 0;
 180         int i;
 181
 182         for (i = start; i < dlen; i++) {
 183                 /* Finished? */
 184                 if (data[i] == delim) {
 185                         if (tmp_port == 0)
 186                                 break;
 187                         *port = htons(tmp_port);
 188                         DEBUGP("get_port: return %d\n", tmp_port);
 189                         return i + 1;
 190                 }
 191                 else if (data[i] >= '0' && data[i] <= '9')
 192                         tmp_port = tmp_port*10 + data[i] - '0';
 193                 else { /* Some other crap */
 194                         DEBUGP("get_port: invalid char.\n");
 195                         break;
 196                 }
 197         }
 198         return 0;
 199 }
 200
 201 /* Returns 0, or length of numbers: |1|132.235.1.2|6275| or |2|3ffe::1|6275| */
 202 static int try_eprt(const char *data, size_t dlen, struct nf_conntrack_man *cmd,
 203                     char term)
 204 {
 205         char delim;
 206         int length;
 207
 208         /* First character is delimiter, then "1" for IPv4 or "2" for IPv6,
 209            then delimiter again. */
 210         if (dlen <= 3) {
 211                 DEBUGP("EPRT: too short\n");
 212                 return 0;
 213         }
 214         delim = data[0];
 215         if (isdigit(delim) || delim < 33 || delim > 126 || data[2] != delim) {
 216                 DEBUGP("try_eprt: invalid delimitter.\n");
 217                 return 0;
 218         }
 219
 220         if ((cmd->l3num == PF_INET && data[1] != '1') ||
 221             (cmd->l3num == PF_INET6 && data[1] != '2')) {
 222                 DEBUGP("EPRT: invalid protocol number.\n");
 223                 return 0;
 224         }
 225
 226         DEBUGP("EPRT: Got %c%c%c\n", delim, data[1], delim);
 227
 228         if (data[1] == '1') {
 229                 u_int32_t array[4];
 230
 231                 /* Now we have IP address. */
 232                 length = try_number(data + 3, dlen - 3, array, 4, '.', delim);
 233                 if (length != 0)
 234                         cmd->u3.ip = htonl((array[0] << 24) | (array[1] << 16)
 235                                            | (array[2] << 8) | array[3]);
 236         } else {
 237                 /* Now we have IPv6 address. */
 238                 length = get_ipv6_addr(data + 3, dlen - 3,
 239                                        (struct in6_addr *)cmd->u3.ip6, delim);
 240         }
 241
 242         if (length == 0)
 243                 return 0;
 244         DEBUGP("EPRT: Got IP address!\n");
 245         /* Start offset includes initial "|1|", and trailing delimiter */
 246         return get_port(data, 3 + length + 1, dlen, delim, &cmd->u.tcp.port);
 247 }
 248
 249 /* Returns 0, or length of numbers: |||6446| */
 250 static int try_epsv_response(const char *data, size_t dlen,
 251                              struct nf_conntrack_man *cmd, char term)
 252 {
 253         char delim;
 254
 255         /* Three delimiters. */
 256         if (dlen <= 3) return 0;
 257         delim = data[0];
 258         if (isdigit(delim) || delim < 33 || delim > 126
 259             || data[1] != delim || data[2] != delim)
 260                 return 0;
 261
 262         return get_port(data, 3, dlen, delim, &cmd->u.tcp.port);
 263 }
 264
 265 /* Return 1 for match, 0 for accept, -1 for partial. */
 266 static int find_pattern(const char *data, size_t dlen,
 267                         const char *pattern, size_t plen,
 268                         char skip, char term,
 269                         unsigned int *numoff,
 270                         unsigned int *numlen,
 271                         struct nf_conntrack_man *cmd,
 272                         int (*getnum)(const char *, size_t,
 273                                       struct nf_conntrack_man *, char))
 274 {
 275         size_t i;
 276
 277         DEBUGP("find_pattern `%s': dlen = %u\n", pattern, dlen);
 278         if (dlen == 0)
 279                 return 0;
 280
 281         if (dlen <= plen) {
 282                 /* Short packet: try for partial? */
 283                 if (strnicmp(data, pattern, dlen) == 0)
 284                         return -1;
 285                 else return 0;
 286         }
 287
 288         if (strnicmp(data, pattern, plen) != 0) {
 289 #if 0
 290                 size_t i;
 291
 292                 DEBUGP("ftp: string mismatch\n");
 293                 for (i = 0; i < plen; i++) {
 294                         DEBUGP("ftp:char %u `%c'(%u) vs `%c'(%u)\n",
 295                                 i, data[i], data[i],
 296                                 pattern[i], pattern[i]);
 297                 }
 298 #endif
 299                 return 0;
 300         }
 301
 302         DEBUGP("Pattern matches!\n");
 303         /* Now we've found the constant string, try to skip
 304            to the 'skip' character */
 305         for (i = plen; data[i] != skip; i++)
 306                 if (i == dlen - 1) return -1;
 307
 308         /* Skip over the last character */
 309         i++;
 310
 311         DEBUGP("Skipped up to `%c'!\n", skip);
 312
 313         *numoff = i;
 314         *numlen = getnum(data + i, dlen - i, cmd, term);
 315         if (!*numlen)
 316                 return -1;
 317
 318         DEBUGP("Match succeeded!\n");
 319         return 1;
 320 }
 321
 322 /* Look up to see if we're just after a \n. */
 323 static int find_nl_seq(u32 seq, const struct nf_ct_ftp_master *info, int dir)
 324 {
 325         unsigned int i;
 326
 327         for (i = 0; i < info->seq_aft_nl_num[dir]; i++)
 328                 if (info->seq_aft_nl[dir][i] == seq)
 329                         return 1;
 330         return 0;
 331 }
 332
 333 /* We don't update if it's older than what we have. */
 334 static void update_nl_seq(u32 nl_seq, struct nf_ct_ftp_master *info, int dir,
 335                           struct sk_buff *skb)
 336 {
 337         unsigned int i, oldest = NUM_SEQ_TO_REMEMBER;
 338
 339         /* Look for oldest: if we find exact match, we're done. */
 340         for (i = 0; i < info->seq_aft_nl_num[dir]; i++) {
 341                 if (info->seq_aft_nl[dir][i] == nl_seq)
 342                         return;
 343
 344                 if (oldest == info->seq_aft_nl_num[dir]
 345                     || before(info->seq_aft_nl[dir][i], oldest))
 346                         oldest = i;
 347         }
 348
 349         if (info->seq_aft_nl_num[dir] < NUM_SEQ_TO_REMEMBER) {
 350                 info->seq_aft_nl[dir][info->seq_aft_nl_num[dir]++] = nl_seq;
 351                 nf_conntrack_event_cache(IPCT_HELPINFO_VOLATILE, skb);
 352         } else if (oldest != NUM_SEQ_TO_REMEMBER) {
 353                 info->seq_aft_nl[dir][oldest] = nl_seq;
 354                 nf_conntrack_event_cache(IPCT_HELPINFO_VOLATILE, skb);
 355         }
 356 }
 357
 358 static int help(struct sk_buff **pskb,
 359                 unsigned int protoff,
 360                 struct nf_conn *ct,
 361                 enum ip_conntrack_info ctinfo)
 362 {
 363         unsigned int dataoff, datalen;
 364         struct tcphdr _tcph, *th;
 365         char *fb_ptr;
 366         int ret;
 367         u32 seq;
 368         int dir = CTINFO2DIR(ctinfo);
 369         unsigned int matchlen, matchoff;
 370         struct nf_ct_ftp_master *ct_ftp_info = &nfct_help(ct)->help.ct_ftp_info;
 371         struct nf_conntrack_expect *exp;
 372         struct nf_conntrack_man cmd = {};
 373         unsigned int i;
 374         int found = 0, ends_in_nl;
 375         typeof(nf_nat_ftp_hook) nf_nat_ftp;
 376
 377         /* Until there's been traffic both ways, don't look in packets. */
 378         if (ctinfo != IP_CT_ESTABLISHED
 379             && ctinfo != IP_CT_ESTABLISHED+IP_CT_IS_REPLY) {
 380                 DEBUGP("ftp: Conntrackinfo = %u\n", ctinfo);
 381                 return NF_ACCEPT;
 382         }
 383
 384         th = skb_header_pointer(*pskb, protoff, sizeof(_tcph), &_tcph);
 385         if (th == NULL)
 386                 return NF_ACCEPT;
 387
 388         dataoff = protoff + th->doff * 4;
 389         /* No data? */
 390         if (dataoff >= (*pskb)->len) {
 391                 DEBUGP("ftp: dataoff(%u) >= skblen(%u)\n", dataoff,
 392                         (*pskb)->len);
 393                 return NF_ACCEPT;
 394         }
 395         datalen = (*pskb)->len - dataoff;
 396
 397         spin_lock_bh(&nf_ftp_lock);
 398         fb_ptr = skb_header_pointer(*pskb, dataoff, datalen, ftp_buffer);
 399         BUG_ON(fb_ptr == NULL);
 400
 401         ends_in_nl = (fb_ptr[datalen - 1] == '\n');
 402         seq = ntohl(th->seq) + datalen;
 403
 404         /* Look up to see if we're just after a \n. */
 405         if (!find_nl_seq(ntohl(th->seq), ct_ftp_info, dir)) {
 406                 /* Now if this ends in \n, update ftp info. */
 407                 DEBUGP("nf_conntrack_ftp_help: wrong seq pos %s(%u) or %s(%u)\n",
 408                        ct_ftp_info->seq_aft_nl_num[dir] > 0 ? "" : "(UNSET)",
 409                        ct_ftp_info->seq_aft_nl[dir][0],
 410                        ct_ftp_info->seq_aft_nl_num[dir] > 1 ? "" : "(UNSET)",
 411                        ct_ftp_info->seq_aft_nl[dir][1]);
 412                 ret = NF_ACCEPT;
 413                 goto out_update_nl;
 414         }
 415
 416         /* Initialize IP/IPv6 addr to expected address (it's not mentioned
 417            in EPSV responses) */
 418         cmd.l3num = ct->tuplehash[dir].tuple.src.l3num;
 419         memcpy(cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all,
 420                sizeof(cmd.u3.all));
 421
 422         for (i = 0; i < ARRAY_SIZE(search[dir]); i++) {
 423                 found = find_pattern(fb_ptr, datalen,
 424                                      search[dir][i].pattern,
 425                                      search[dir][i].plen,
 426                                      search[dir][i].skip,
 427                                      search[dir][i].term,
 428                                      &matchoff, &matchlen,
 429                                      &cmd,
 430                                      search[dir][i].getnum);
 431                 if (found) break;
 432         }
 433         if (found == -1) {
 434                 /* We don't usually drop packets.  After all, this is
 435                    connection tracking, not packet filtering.
 436                    However, it is necessary for accurate tracking in
 437                    this case. */
 438                 if (net_ratelimit())
 439                         printk("conntrack_ftp: partial %s %u+%u\n",
 440                                search[dir][i].pattern,
 441                                ntohl(th->seq), datalen);
 442                 ret = NF_DROP;
 443                 goto out;
 444         } else if (found == 0) { /* No match */
 445                 ret = NF_ACCEPT;
 446                 goto out_update_nl;
 447         }
 448
 449         DEBUGP("conntrack_ftp: match `%.*s' (%u bytes at %u)\n",
 450                (int)matchlen, fb_ptr + matchoff,
 451                matchlen, ntohl(th->seq) + matchoff);
 452
 453         exp = nf_conntrack_expect_alloc(ct);
 454         if (exp == NULL) {
 455                 ret = NF_DROP;
 456                 goto out;
 457         }
 458
 459         /* We refer to the reverse direction ("!dir") tuples here,
 460          * because we're expecting something in the other direction.
 461          * Doesn't matter unless NAT is happening.  */
 462         exp->tuple.dst.u3 = ct->tuplehash[!dir].tuple.dst.u3;
 463
 464         /* Update the ftp info */
 465         if ((cmd.l3num == ct->tuplehash[dir].tuple.src.l3num) &&
 466             memcmp(&cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all,
 467                      sizeof(cmd.u3.all))) {
 468                 /* Enrico Scholz's passive FTP to partially RNAT'd ftp
 469                    server: it really wants us to connect to a
 470                    different IP address.  Simply don't record it for
 471                    NAT. */
 472                 if (cmd.l3num == PF_INET) {
 473                         DEBUGP("conntrack_ftp: NOT RECORDING: " NIPQUAD_FMT " != " NIPQUAD_FMT "\n",
 474                                NIPQUAD(cmd.u3.ip),
 475                                NIPQUAD(ct->tuplehash[dir].tuple.src.u3.ip));
 476                 } else {
 477                         DEBUGP("conntrack_ftp: NOT RECORDING: " NIP6_FMT " != " NIP6_FMT "\n",
 478                                NIP6(*((struct in6_addr *)cmd.u3.ip6)),
 479                                NIP6(*((struct in6_addr *)ct->tuplehash[dir]
 480                                                         .tuple.src.u3.ip6)));
 481                 }
 482
 483                 /* Thanks to Cristiano Lincoln Mattos
 484                    <lincoln@cesar.org.br> for reporting this potential
 485                    problem (DMZ machines opening holes to internal
 486                    networks, or the packet filter itself). */
 487                 if (!loose) {
 488                         ret = NF_ACCEPT;
 489                         goto out_put_expect;
 490                 }
 491                 memcpy(&exp->tuple.dst.u3, &cmd.u3.all,
 492                        sizeof(exp->tuple.dst.u3));
 493         }
 494
 495         exp->tuple.src.u3 = ct->tuplehash[!dir].tuple.src.u3;
 496         exp->tuple.src.l3num = cmd.l3num;
 497         exp->tuple.src.u.tcp.port = 0;
 498         exp->tuple.dst.u.tcp.port = cmd.u.tcp.port;
 499         exp->tuple.dst.protonum = IPPROTO_TCP;
 500
 501         exp->mask = (struct nf_conntrack_tuple)
 502                     { .src = { .l3num = 0xFFFF,
 503                                .u = { .tcp = { 0 }},
 504                              },
 505                       .dst = { .protonum = 0xFF,
 506                                .u = { .tcp = { __constant_htons(0xFFFF) }},
 507                              },
 508                     };
 509         if (cmd.l3num == PF_INET) {
 510                 exp->mask.src.u3.ip = htonl(0xFFFFFFFF);
 511                 exp->mask.dst.u3.ip = htonl(0xFFFFFFFF);
 512         } else {
 513                 memset(exp->mask.src.u3.ip6, 0xFF,
 514                        sizeof(exp->mask.src.u3.ip6));
 515                 memset(exp->mask.dst.u3.ip6, 0xFF,
 516                        sizeof(exp->mask.src.u3.ip6));
 517         }
 518
 519         exp->expectfn = NULL;
 520         exp->helper = NULL;
 521         exp->flags = 0;
 522
 523         /* Now, NAT might want to mangle the packet, and register the
 524          * (possibly changed) expectation itself. */
 525         nf_nat_ftp = rcu_dereference(nf_nat_ftp_hook);
 526         if (nf_nat_ftp && ct->status & IPS_NAT_MASK)
 527                 ret = nf_nat_ftp(pskb, ctinfo, search[dir][i].ftptype,
 528                                  matchoff, matchlen, exp, &seq);
 529         else {
 530                 /* Can't expect this?  Best to drop packet now. */
 531                 if (nf_conntrack_expect_related(exp) != 0)
 532                         ret = NF_DROP;
 533                 else
 534                         ret = NF_ACCEPT;
 535         }
 536
 537 out_put_expect:
 538         nf_conntrack_expect_put(exp);
 539
 540 out_update_nl:
 541         /* Now if this ends in \n, update ftp info.  Seq may have been
 542          * adjusted by NAT code. */
 543         if (ends_in_nl)
 544                 update_nl_seq(seq, ct_ftp_info, dir, *pskb);
 545  out:
 546         spin_unlock_bh(&nf_ftp_lock);
 547         return ret;
 548 }
 549
 550 static struct nf_conntrack_helper ftp[MAX_PORTS][2];
 551 static char ftp_names[MAX_PORTS][2][sizeof("ftp-65535")];
 552
 553 /* don't make this __exit, since it's called from __init ! */
 554 static void nf_conntrack_ftp_fini(void)
 555 {
 556         int i, j;
 557         for (i = 0; i < ports_c; i++) {
 558                 for (j = 0; j < 2; j++) {
 559                         if (ftp[i][j].me == NULL)
 560                                 continue;
 561
 562                         DEBUGP("nf_ct_ftp: unregistering helper for pf: %d "
 563                                "port: %d\n",
 564                                 ftp[i][j].tuple.src.l3num, ports[i]);
 565                         nf_conntrack_helper_unregister(&ftp[i][j]);
 566                 }
 567         }
 568
 569         kfree(ftp_buffer);
 570 }
 571
 572 static int __init nf_conntrack_ftp_init(void)
 573 {
 574         int i, j = -1, ret = 0;
 575         char *tmpname;
 576
 577         ftp_buffer = kmalloc(65536, GFP_KERNEL);
 578         if (!ftp_buffer)
 579                 return -ENOMEM;
 580
 581         if (ports_c == 0)
 582                 ports[ports_c++] = FTP_PORT;
 583
 584         /* FIXME should be configurable whether IPv4 and IPv6 FTP connections
 585                  are tracked or not - YK */
 586         for (i = 0; i < ports_c; i++) {
 587                 ftp[i][0].tuple.src.l3num = PF_INET;
 588                 ftp[i][1].tuple.src.l3num = PF_INET6;
 589                 for (j = 0; j < 2; j++) {
 590                         ftp[i][j].tuple.src.u.tcp.port = htons(ports[i]);
 591                         ftp[i][j].tuple.dst.protonum = IPPROTO_TCP;
 592                         ftp[i][j].mask.src.l3num = 0xFFFF;
 593                         ftp[i][j].mask.src.u.tcp.port = htons(0xFFFF);
 594                         ftp[i][j].mask.dst.protonum = 0xFF;
 595                         ftp[i][j].max_expected = 1;
 596                         ftp[i][j].timeout = 5 * 60;     /* 5 Minutes */
 597                         ftp[i][j].me = THIS_MODULE;
 598                         ftp[i][j].help = help;
 599                         tmpname = &ftp_names[i][j][0];
 600                         if (ports[i] == FTP_PORT)
 601                                 sprintf(tmpname, "ftp");
 602                         else
 603                                 sprintf(tmpname, "ftp-%d", ports[i]);
 604                         ftp[i][j].name = tmpname;
 605
 606                         DEBUGP("nf_ct_ftp: registering helper for pf: %d "
 607                                "port: %d\n",
 608                                 ftp[i][j].tuple.src.l3num, ports[i]);
 609                         ret = nf_conntrack_helper_register(&ftp[i][j]);
 610                         if (ret) {
 611                                 printk("nf_ct_ftp: failed to register helper "
 612                                        " for pf: %d port: %d\n",
 613                                         ftp[i][j].tuple.src.l3num, ports[i]);
 614                                 nf_conntrack_ftp_fini();
 615                                 return ret;
 616                         }
 617                 }
 618         }
 619
 620         return 0;
 621 }
 622
 623 module_init(nf_conntrack_ftp_init);
 624 module_exit(nf_conntrack_ftp_fini);