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 <net/checksum.h>
  25 #include <net/tcp.h>
  26
  27 #include <net/netfilter/nf_conntrack.h>
  28 #include <net/netfilter/nf_conntrack_helper.h>
  29 #include <linux/netfilter/nf_conntrack_ftp.h>
  30
  31 MODULE_LICENSE("GPL");
  32 MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
  33 MODULE_DESCRIPTION("ftp connection tracking helper");
  34
  35 /* This is slow, but it's simple. --RR */
  36 static char *ftp_buffer;
  37
  38 static DEFINE_SPINLOCK(nf_ftp_lock);
  39
  40 #define MAX_PORTS 8
  41 static u_int16_t ports[MAX_PORTS];
  42 static unsigned int ports_c;
  43 module_param_array(ports, ushort, &ports_c, 0400);
  44
  45 static int loose;
  46 module_param(loose, bool, 0600);
  47
  48 unsigned int (*nf_nat_ftp_hook)(struct sk_buff **pskb,
  49                                 enum ip_conntrack_info ctinfo,
  50                                 enum ip_ct_ftp_type type,
  51                                 unsigned int matchoff,
  52                                 unsigned int matchlen,
  53                                 struct nf_conntrack_expect *exp,
  54                                 u32 *seq);
  55 EXPORT_SYMBOL_GPL(nf_nat_ftp_hook);
  56
  57 #if 0
  58 #define DEBUGP printk
  59 #else
  60 #define DEBUGP(format, args...)
  61 #endif
  62
  63 static int try_rfc959(const char *, size_t, struct nf_conntrack_man *, char);
  64 static int try_eprt(const char *, size_t, struct nf_conntrack_man *, char);
  65 static int try_epsv_response(const char *, size_t, struct nf_conntrack_man *,
  66                              char);
  67
  68 static struct ftp_search {
  69         const char *pattern;
  70         size_t plen;
  71         char skip;
  72         char term;
  73         enum ip_ct_ftp_type ftptype;
  74         int (*getnum)(const char *, size_t, struct nf_conntrack_man *, char);
  75 } search[IP_CT_DIR_MAX][2] = {
  76         [IP_CT_DIR_ORIGINAL] = {
  77                 {
  78                         .pattern        = "PORT",
  79                         .plen           = sizeof("PORT") - 1,
  80                         .skip           = ' ',
  81                         .term           = '\r',
  82                         .ftptype        = IP_CT_FTP_PORT,
  83                         .getnum         = try_rfc959,
  84                 },
  85                 {
  86                         .pattern        = "EPRT",
  87                         .plen           = sizeof("EPRT") - 1,
  88                         .skip           = ' ',
  89                         .term           = '\r',
  90                         .ftptype        = IP_CT_FTP_EPRT,
  91                         .getnum         = try_eprt,
  92                 },
  93         },
  94         [IP_CT_DIR_REPLY] = {
  95                 {
  96                         .pattern        = "227 ",
  97                         .plen           = sizeof("227 ") - 1,
  98                         .skip           = '(',
  99                         .term           = ')',
 100                         .ftptype        = IP_CT_FTP_PASV,
 101                         .getnum         = try_rfc959,
 102                 },
 103                 {
 104                         .pattern        = "229 ",
 105                         .plen           = sizeof("229 ") - 1,
 106                         .skip           = '(',
 107                         .term           = ')',
 108                         .ftptype        = IP_CT_FTP_EPSV,
 109                         .getnum         = try_epsv_response,
 110                 },
 111         },
 112 };
 113
 114 /* This code is based on inet_pton() in glibc-2.2.4 */
 115 static int
 116 get_ipv6_addr(const char *src, size_t dlen, struct in6_addr *dst, u_int8_t term)
 117 {
 118         static const char xdigits[] = "0123456789abcdef";
 119         u_int8_t tmp[16], *tp, *endp, *colonp;
 120         int ch, saw_xdigit;
 121         u_int32_t val;
 122         size_t clen = 0;
 123
 124         tp = memset(tmp, '\0', sizeof(tmp));
 125         endp = tp + sizeof(tmp);
 126         colonp = NULL;
 127
 128         /* Leading :: requires some special handling. */
 129         if (*src == ':'){
 130                 if (*++src != ':') {
 131                         DEBUGP("invalid \":\" at the head of addr\n");
 132                         return 0;
 133                 }
 134                 clen++;
 135         }
 136
 137         saw_xdigit = 0;
 138         val = 0;
 139         while ((clen < dlen) && (*src != term)) {
 140                 const char *pch;
 141
 142                 ch = tolower(*src++);
 143                 clen++;
 144
 145                 pch = strchr(xdigits, ch);
 146                 if (pch != NULL) {
 147                         val <<= 4;
 148                         val |= (pch - xdigits);
 149                         if (val > 0xffff)
 150                                 return 0;
 151
 152                         saw_xdigit = 1;
 153                         continue;
 154                 }
 155                 if (ch != ':') {
 156                         DEBUGP("get_ipv6_addr: invalid char. \'%c\'\n", ch);
 157                         return 0;
 158                 }
 159
 160                 if (!saw_xdigit) {
 161                         if (colonp) {
 162                                 DEBUGP("invalid location of \"::\".\n");
 163                                 return 0;
 164                         }
 165                         colonp = tp;
 166                         continue;
 167                 } else if (*src == term) {
 168                         DEBUGP("trancated IPv6 addr\n");
 169                         return 0;
 170                 }
 171
 172                 if (tp + 2 > endp)
 173                         return 0;
 174                 *tp++ = (u_int8_t) (val >> 8) & 0xff;
 175                 *tp++ = (u_int8_t) val & 0xff;
 176
 177                 saw_xdigit = 0;
 178                 val = 0;
 179                 continue;
 180         }
 181         if (saw_xdigit) {
 182                 if (tp + 2 > endp)
 183                         return 0;
 184                 *tp++ = (u_int8_t) (val >> 8) & 0xff;
 185                 *tp++ = (u_int8_t) val & 0xff;
 186         }
 187         if (colonp != NULL) {
 188                 /*
 189                  * Since some memmove()'s erroneously fail to handle
 190                  * overlapping regions, we'll do the shift by hand.
 191                  */
 192                 const int n = tp - colonp;
 193                 int i;
 194
 195                 if (tp == endp)
 196                         return 0;
 197
 198                 for (i = 1; i <= n; i++) {
 199                         endp[- i] = colonp[n - i];
 200                         colonp[n - i] = 0;
 201                 }
 202                 tp = endp;
 203         }
 204         if (tp != endp || (*src != term))
 205                 return 0;
 206
 207         memcpy(dst->s6_addr, tmp, sizeof(dst->s6_addr));
 208         return clen;
 209 }
 210
 211 static int try_number(const char *data, size_t dlen, u_int32_t array[],
 212                       int array_size, char sep, char term)
 213 {
 214         u_int32_t i, len;
 215
 216         memset(array, 0, sizeof(array[0])*array_size);
 217
 218         /* Keep data pointing at next char. */
 219         for (i = 0, len = 0; len < dlen && i < array_size; len++, data++) {
 220                 if (*data >= '0' && *data <= '9') {
 221                         array[i] = array[i]*10 + *data - '0';
 222                 }
 223                 else if (*data == sep)
 224                         i++;
 225                 else {
 226                         /* Unexpected character; true if it's the
 227                            terminator and we're finished. */
 228                         if (*data == term && i == array_size - 1)
 229                                 return len;
 230
 231                         DEBUGP("Char %u (got %u nums) `%u' unexpected\n",
 232                                len, i, *data);
 233                         return 0;
 234                 }
 235         }
 236         DEBUGP("Failed to fill %u numbers separated by %c\n", array_size, sep);
 237
 238         return 0;
 239 }
 240
 241 /* Returns 0, or length of numbers: 192,168,1,1,5,6 */
 242 static int try_rfc959(const char *data, size_t dlen,
 243                       struct nf_conntrack_man *cmd, char term)
 244 {
 245         int length;
 246         u_int32_t array[6];
 247
 248         length = try_number(data, dlen, array, 6, ',', term);
 249         if (length == 0)
 250                 return 0;
 251
 252         cmd->u3.ip =  htonl((array[0] << 24) | (array[1] << 16) |
 253                                     (array[2] << 8) | array[3]);
 254         cmd->u.tcp.port = htons((array[4] << 8) | array[5]);
 255         return length;
 256 }
 257
 258 /* Grab port: number up to delimiter */
 259 static int get_port(const char *data, int start, size_t dlen, char delim,
 260                     u_int16_t *port)
 261 {
 262         u_int16_t tmp_port = 0;
 263         int i;
 264
 265         for (i = start; i < dlen; i++) {
 266                 /* Finished? */
 267                 if (data[i] == delim) {
 268                         if (tmp_port == 0)
 269                                 break;
 270                         *port = htons(tmp_port);
 271                         DEBUGP("get_port: return %d\n", tmp_port);
 272                         return i + 1;
 273                 }
 274                 else if (data[i] >= '0' && data[i] <= '9')
 275                         tmp_port = tmp_port*10 + data[i] - '0';
 276                 else { /* Some other crap */
 277                         DEBUGP("get_port: invalid char.\n");
 278                         break;
 279                 }
 280         }
 281         return 0;
 282 }
 283
 284 /* Returns 0, or length of numbers: |1|132.235.1.2|6275| or |2|3ffe::1|6275| */
 285 static int try_eprt(const char *data, size_t dlen, struct nf_conntrack_man *cmd,
 286                     char term)
 287 {
 288         char delim;
 289         int length;
 290
 291         /* First character is delimiter, then "1" for IPv4 or "2" for IPv6,
 292            then delimiter again. */
 293         if (dlen <= 3) {
 294                 DEBUGP("EPRT: too short\n");
 295                 return 0;
 296         }
 297         delim = data[0];
 298         if (isdigit(delim) || delim < 33 || delim > 126 || data[2] != delim) {
 299                 DEBUGP("try_eprt: invalid delimitter.\n");
 300                 return 0;
 301         }
 302
 303         if ((cmd->l3num == PF_INET && data[1] != '1') ||
 304             (cmd->l3num == PF_INET6 && data[1] != '2')) {
 305                 DEBUGP("EPRT: invalid protocol number.\n");
 306                 return 0;
 307         }
 308
 309         DEBUGP("EPRT: Got %c%c%c\n", delim, data[1], delim);
 310
 311         if (data[1] == '1') {
 312                 u_int32_t array[4];
 313
 314                 /* Now we have IP address. */
 315                 length = try_number(data + 3, dlen - 3, array, 4, '.', delim);
 316                 if (length != 0)
 317                         cmd->u3.ip = htonl((array[0] << 24) | (array[1] << 16)
 318                                            | (array[2] << 8) | array[3]);
 319         } else {
 320                 /* Now we have IPv6 address. */
 321                 length = get_ipv6_addr(data + 3, dlen - 3,
 322                                        (struct in6_addr *)cmd->u3.ip6, delim);
 323         }
 324
 325         if (length == 0)
 326                 return 0;
 327         DEBUGP("EPRT: Got IP address!\n");
 328         /* Start offset includes initial "|1|", and trailing delimiter */
 329         return get_port(data, 3 + length + 1, dlen, delim, &cmd->u.tcp.port);
 330 }
 331
 332 /* Returns 0, or length of numbers: |||6446| */
 333 static int try_epsv_response(const char *data, size_t dlen,
 334                              struct nf_conntrack_man *cmd, char term)
 335 {
 336         char delim;
 337
 338         /* Three delimiters. */
 339         if (dlen <= 3) return 0;
 340         delim = data[0];
 341         if (isdigit(delim) || delim < 33 || delim > 126
 342             || data[1] != delim || data[2] != delim)
 343                 return 0;
 344
 345         return get_port(data, 3, dlen, delim, &cmd->u.tcp.port);
 346 }
 347
 348 /* Return 1 for match, 0 for accept, -1 for partial. */
 349 static int find_pattern(const char *data, size_t dlen,
 350                         const char *pattern, size_t plen,
 351                         char skip, char term,
 352                         unsigned int *numoff,
 353                         unsigned int *numlen,
 354                         struct nf_conntrack_man *cmd,
 355                         int (*getnum)(const char *, size_t,
 356                                       struct nf_conntrack_man *, char))
 357 {
 358         size_t i;
 359
 360         DEBUGP("find_pattern `%s': dlen = %u\n", pattern, dlen);
 361         if (dlen == 0)
 362                 return 0;
 363
 364         if (dlen <= plen) {
 365                 /* Short packet: try for partial? */
 366                 if (strnicmp(data, pattern, dlen) == 0)
 367                         return -1;
 368                 else return 0;
 369         }
 370
 371         if (strnicmp(data, pattern, plen) != 0) {
 372 #if 0
 373                 size_t i;
 374
 375                 DEBUGP("ftp: string mismatch\n");
 376                 for (i = 0; i < plen; i++) {
 377                         DEBUGP("ftp:char %u `%c'(%u) vs `%c'(%u)\n",
 378                                 i, data[i], data[i],
 379                                 pattern[i], pattern[i]);
 380                 }
 381 #endif
 382                 return 0;
 383         }
 384
 385         DEBUGP("Pattern matches!\n");
 386         /* Now we've found the constant string, try to skip
 387            to the 'skip' character */
 388         for (i = plen; data[i] != skip; i++)
 389                 if (i == dlen - 1) return -1;
 390
 391         /* Skip over the last character */
 392         i++;
 393
 394         DEBUGP("Skipped up to `%c'!\n", skip);
 395
 396         *numoff = i;
 397         *numlen = getnum(data + i, dlen - i, cmd, term);
 398         if (!*numlen)
 399                 return -1;
 400
 401         DEBUGP("Match succeeded!\n");
 402         return 1;
 403 }
 404
 405 /* Look up to see if we're just after a \n. */
 406 static int find_nl_seq(u32 seq, const struct ip_ct_ftp_master *info, int dir)
 407 {
 408         unsigned int i;
 409
 410         for (i = 0; i < info->seq_aft_nl_num[dir]; i++)
 411                 if (info->seq_aft_nl[dir][i] == seq)
 412                         return 1;
 413         return 0;
 414 }
 415
 416 /* We don't update if it's older than what we have. */
 417 static void update_nl_seq(u32 nl_seq, struct ip_ct_ftp_master *info, int dir,
 418                           struct sk_buff *skb)
 419 {
 420         unsigned int i, oldest = NUM_SEQ_TO_REMEMBER;
 421
 422         /* Look for oldest: if we find exact match, we're done. */
 423         for (i = 0; i < info->seq_aft_nl_num[dir]; i++) {
 424                 if (info->seq_aft_nl[dir][i] == nl_seq)
 425                         return;
 426
 427                 if (oldest == info->seq_aft_nl_num[dir]
 428                     || before(info->seq_aft_nl[dir][i], oldest))
 429                         oldest = i;
 430         }
 431
 432         if (info->seq_aft_nl_num[dir] < NUM_SEQ_TO_REMEMBER) {
 433                 info->seq_aft_nl[dir][info->seq_aft_nl_num[dir]++] = nl_seq;
 434                 nf_conntrack_event_cache(IPCT_HELPINFO_VOLATILE, skb);
 435         } else if (oldest != NUM_SEQ_TO_REMEMBER) {
 436                 info->seq_aft_nl[dir][oldest] = nl_seq;
 437                 nf_conntrack_event_cache(IPCT_HELPINFO_VOLATILE, skb);
 438         }
 439 }
 440
 441 static int help(struct sk_buff **pskb,
 442                 unsigned int protoff,
 443                 struct nf_conn *ct,
 444                 enum ip_conntrack_info ctinfo)
 445 {
 446         unsigned int dataoff, datalen;
 447         struct tcphdr _tcph, *th;
 448         char *fb_ptr;
 449         int ret;
 450         u32 seq;
 451         int dir = CTINFO2DIR(ctinfo);
 452         unsigned int matchlen, matchoff;
 453         struct ip_ct_ftp_master *ct_ftp_info = &nfct_help(ct)->help.ct_ftp_info;
 454         struct nf_conntrack_expect *exp;
 455         struct nf_conntrack_man cmd = {};
 456
 457         unsigned int i;
 458         int found = 0, ends_in_nl;
 459
 460         /* Until there's been traffic both ways, don't look in packets. */
 461         if (ctinfo != IP_CT_ESTABLISHED
 462             && ctinfo != IP_CT_ESTABLISHED+IP_CT_IS_REPLY) {
 463                 DEBUGP("ftp: Conntrackinfo = %u\n", ctinfo);
 464                 return NF_ACCEPT;
 465         }
 466
 467         th = skb_header_pointer(*pskb, protoff, sizeof(_tcph), &_tcph);
 468         if (th == NULL)
 469                 return NF_ACCEPT;
 470
 471         dataoff = protoff + th->doff * 4;
 472         /* No data? */
 473         if (dataoff >= (*pskb)->len) {
 474                 DEBUGP("ftp: dataoff(%u) >= skblen(%u)\n", dataoff,
 475                         (*pskb)->len);
 476                 return NF_ACCEPT;
 477         }
 478         datalen = (*pskb)->len - dataoff;
 479
 480         spin_lock_bh(&nf_ftp_lock);
 481         fb_ptr = skb_header_pointer(*pskb, dataoff, datalen, ftp_buffer);
 482         BUG_ON(fb_ptr == NULL);
 483
 484         ends_in_nl = (fb_ptr[datalen - 1] == '\n');
 485         seq = ntohl(th->seq) + datalen;
 486
 487         /* Look up to see if we're just after a \n. */
 488         if (!find_nl_seq(ntohl(th->seq), ct_ftp_info, dir)) {
 489                 /* Now if this ends in \n, update ftp info. */
 490                 DEBUGP("nf_conntrack_ftp_help: wrong seq pos %s(%u) or %s(%u)\n",
 491                        ct_ftp_info->seq_aft_nl_num[dir] > 0 ? "" : "(UNSET)",
 492                        ct_ftp_info->seq_aft_nl[dir][0],
 493                        ct_ftp_info->seq_aft_nl_num[dir] > 1 ? "" : "(UNSET)",
 494                        ct_ftp_info->seq_aft_nl[dir][1]);
 495                 ret = NF_ACCEPT;
 496                 goto out_update_nl;
 497         }
 498
 499         /* Initialize IP/IPv6 addr to expected address (it's not mentioned
 500            in EPSV responses) */
 501         cmd.l3num = ct->tuplehash[dir].tuple.src.l3num;
 502         memcpy(cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all,
 503                sizeof(cmd.u3.all));
 504
 505         for (i = 0; i < ARRAY_SIZE(search[dir]); i++) {
 506                 found = find_pattern(fb_ptr, datalen,
 507                                      search[dir][i].pattern,
 508                                      search[dir][i].plen,
 509                                      search[dir][i].skip,
 510                                      search[dir][i].term,
 511                                      &matchoff, &matchlen,
 512                                      &cmd,
 513                                      search[dir][i].getnum);
 514                 if (found) break;
 515         }
 516         if (found == -1) {
 517                 /* We don't usually drop packets.  After all, this is
 518                    connection tracking, not packet filtering.
 519                    However, it is necessary for accurate tracking in
 520                    this case. */
 521                 if (net_ratelimit())
 522                         printk("conntrack_ftp: partial %s %u+%u\n",
 523                                search[dir][i].pattern,
 524                                ntohl(th->seq), datalen);
 525                 ret = NF_DROP;
 526                 goto out;
 527         } else if (found == 0) { /* No match */
 528                 ret = NF_ACCEPT;
 529                 goto out_update_nl;
 530         }
 531
 532         DEBUGP("conntrack_ftp: match `%.*s' (%u bytes at %u)\n",
 533                (int)matchlen, fb_ptr + matchoff,
 534                matchlen, ntohl(th->seq) + matchoff);
 535
 536         exp = nf_conntrack_expect_alloc(ct);
 537         if (exp == NULL) {
 538                 ret = NF_DROP;
 539                 goto out;
 540         }
 541
 542         /* We refer to the reverse direction ("!dir") tuples here,
 543          * because we're expecting something in the other direction.
 544          * Doesn't matter unless NAT is happening.  */
 545         exp->tuple.dst.u3 = ct->tuplehash[!dir].tuple.dst.u3;
 546
 547         /* Update the ftp info */
 548         if ((cmd.l3num == ct->tuplehash[dir].tuple.src.l3num) &&
 549             memcmp(&cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all,
 550                      sizeof(cmd.u3.all))) {
 551                 /* Enrico Scholz's passive FTP to partially RNAT'd ftp
 552                    server: it really wants us to connect to a
 553                    different IP address.  Simply don't record it for
 554                    NAT. */
 555                 if (cmd.l3num == PF_INET) {
 556                         DEBUGP("conntrack_ftp: NOT RECORDING: " NIPQUAD_FMT " != " NIPQUAD_FMT "\n",
 557                                NIPQUAD(cmd.u3.ip),
 558                                NIPQUAD(ct->tuplehash[dir].tuple.src.u3.ip));
 559                 } else {
 560                         DEBUGP("conntrack_ftp: NOT RECORDING: " NIP6_FMT " != " NIP6_FMT "\n",
 561                                NIP6(*((struct in6_addr *)cmd.u3.ip6)),
 562                                NIP6(*((struct in6_addr *)ct->tuplehash[dir]
 563                                                         .tuple.src.u3.ip6)));
 564                 }
 565
 566                 /* Thanks to Cristiano Lincoln Mattos
 567                    <lincoln@cesar.org.br> for reporting this potential
 568                    problem (DMZ machines opening holes to internal
 569                    networks, or the packet filter itself). */
 570                 if (!loose) {
 571                         ret = NF_ACCEPT;
 572                         goto out_put_expect;
 573                 }
 574                 memcpy(&exp->tuple.dst.u3, &cmd.u3.all,
 575                        sizeof(exp->tuple.dst.u3));
 576         }
 577
 578         exp->tuple.src.u3 = ct->tuplehash[!dir].tuple.src.u3;
 579         exp->tuple.src.l3num = cmd.l3num;
 580         exp->tuple.src.u.tcp.port = 0;
 581         exp->tuple.dst.u.tcp.port = cmd.u.tcp.port;
 582         exp->tuple.dst.protonum = IPPROTO_TCP;
 583
 584         exp->mask = (struct nf_conntrack_tuple)
 585                     { .src = { .l3num = 0xFFFF,
 586                                .u = { .tcp = { 0 }},
 587                              },
 588                       .dst = { .protonum = 0xFF,
 589                                .u = { .tcp = { 0xFFFF }},
 590                              },
 591                     };
 592         if (cmd.l3num == PF_INET) {
 593                 exp->mask.src.u3.ip = 0xFFFFFFFF;
 594                 exp->mask.dst.u3.ip = 0xFFFFFFFF;
 595         } else {
 596                 memset(exp->mask.src.u3.ip6, 0xFF,
 597                        sizeof(exp->mask.src.u3.ip6));
 598                 memset(exp->mask.dst.u3.ip6, 0xFF,
 599                        sizeof(exp->mask.src.u3.ip6));
 600         }
 601
 602         exp->expectfn = NULL;
 603         exp->flags = 0;
 604
 605         /* Now, NAT might want to mangle the packet, and register the
 606          * (possibly changed) expectation itself. */
 607         if (nf_nat_ftp_hook)
 608                 ret = nf_nat_ftp_hook(pskb, ctinfo, search[dir][i].ftptype,
 609                                       matchoff, matchlen, exp, &seq);
 610         else {
 611                 /* Can't expect this?  Best to drop packet now. */
 612                 if (nf_conntrack_expect_related(exp) != 0)
 613                         ret = NF_DROP;
 614                 else
 615                         ret = NF_ACCEPT;
 616         }
 617
 618 out_put_expect:
 619         nf_conntrack_expect_put(exp);
 620
 621 out_update_nl:
 622         /* Now if this ends in \n, update ftp info.  Seq may have been
 623          * adjusted by NAT code. */
 624         if (ends_in_nl)
 625                 update_nl_seq(seq, ct_ftp_info, dir, *pskb);
 626  out:
 627         spin_unlock_bh(&nf_ftp_lock);
 628         return ret;
 629 }
 630
 631 static struct nf_conntrack_helper ftp[MAX_PORTS][2];
 632 static char ftp_names[MAX_PORTS][2][sizeof("ftp-65535")];
 633
 634 /* don't make this __exit, since it's called from __init ! */
 635 static void nf_conntrack_ftp_fini(void)
 636 {
 637         int i, j;
 638         for (i = 0; i < ports_c; i++) {
 639                 for (j = 0; j < 2; j++) {
 640                         if (ftp[i][j].me == NULL)
 641                                 continue;
 642
 643                         DEBUGP("nf_ct_ftp: unregistering helper for pf: %d "
 644                                "port: %d\n",
 645                                 ftp[i][j].tuple.src.l3num, ports[i]);
 646                         nf_conntrack_helper_unregister(&ftp[i][j]);
 647                 }
 648         }
 649
 650         kfree(ftp_buffer);
 651 }
 652
 653 static int __init nf_conntrack_ftp_init(void)
 654 {
 655         int i, j = -1, ret = 0;
 656         char *tmpname;
 657
 658         ftp_buffer = kmalloc(65536, GFP_KERNEL);
 659         if (!ftp_buffer)
 660                 return -ENOMEM;
 661
 662         if (ports_c == 0)
 663                 ports[ports_c++] = FTP_PORT;
 664
 665         /* FIXME should be configurable whether IPv4 and IPv6 FTP connections
 666                  are tracked or not - YK */
 667         for (i = 0; i < ports_c; i++) {
 668                 ftp[i][0].tuple.src.l3num = PF_INET;
 669                 ftp[i][1].tuple.src.l3num = PF_INET6;
 670                 for (j = 0; j < 2; j++) {
 671                         ftp[i][j].tuple.src.u.tcp.port = htons(ports[i]);
 672                         ftp[i][j].tuple.dst.protonum = IPPROTO_TCP;
 673                         ftp[i][j].mask.src.u.tcp.port = 0xFFFF;
 674                         ftp[i][j].mask.dst.protonum = 0xFF;
 675                         ftp[i][j].max_expected = 1;
 676                         ftp[i][j].timeout = 5 * 60;     /* 5 Minutes */
 677                         ftp[i][j].me = THIS_MODULE;
 678                         ftp[i][j].help = help;
 679                         tmpname = &ftp_names[i][j][0];
 680                         if (ports[i] == FTP_PORT)
 681                                 sprintf(tmpname, "ftp");
 682                         else
 683                                 sprintf(tmpname, "ftp-%d", ports[i]);
 684                         ftp[i][j].name = tmpname;
 685
 686                         DEBUGP("nf_ct_ftp: registering helper for pf: %d "
 687                                "port: %d\n",
 688                                 ftp[i][j].tuple.src.l3num, ports[i]);
 689                         ret = nf_conntrack_helper_register(&ftp[i][j]);
 690                         if (ret) {
 691                                 printk("nf_ct_ftp: failed to register helper "
 692                                        " for pf: %d port: %d\n",
 693                                         ftp[i][j].tuple.src.l3num, ports[i]);
 694                                 nf_conntrack_ftp_fini();
 695                                 return ret;
 696                         }
 697                 }
 698         }
 699
 700         return 0;
 701 }
 702
 703 module_init(nf_conntrack_ftp_init);
 704 module_exit(nf_conntrack_ftp_fini);