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