This commit was manufactured by cvs2svn to create branch 'vserver'.
[linux-2.6.git] / net / netfilter / nf_conntrack_ftp.c
diff --git a/net/netfilter/nf_conntrack_ftp.c b/net/netfilter/nf_conntrack_ftp.c
new file mode 100644 (file)
index 0000000..e38a4b5
--- /dev/null
@@ -0,0 +1,696 @@
+/* FTP extension for connection tracking. */
+
+/* (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
+ * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
+ *     - enable working with Layer 3 protocol independent connection tracking.
+ *     - track EPRT and EPSV commands with IPv6 address.
+ *
+ * Derived from net/ipv4/netfilter/ip_conntrack_ftp.c
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/netfilter.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/ctype.h>
+#include <net/checksum.h>
+#include <net/tcp.h>
+
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_helper.h>
+#include <linux/netfilter/nf_conntrack_ftp.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
+MODULE_DESCRIPTION("ftp connection tracking helper");
+
+/* This is slow, but it's simple. --RR */
+static char *ftp_buffer;
+
+static DEFINE_SPINLOCK(nf_ftp_lock);
+
+#define MAX_PORTS 8
+static u_int16_t ports[MAX_PORTS];
+static unsigned int ports_c;
+module_param_array(ports, ushort, &ports_c, 0400);
+
+static int loose;
+module_param(loose, bool, 0600);
+
+unsigned int (*nf_nat_ftp_hook)(struct sk_buff **pskb,
+                               enum ip_conntrack_info ctinfo,
+                               enum ip_ct_ftp_type type,
+                               unsigned int matchoff,
+                               unsigned int matchlen,
+                               struct nf_conntrack_expect *exp,
+                               u32 *seq);
+EXPORT_SYMBOL_GPL(nf_nat_ftp_hook);
+
+#if 0
+#define DEBUGP printk
+#else
+#define DEBUGP(format, args...)
+#endif
+
+static int try_rfc959(const char *, size_t, struct nf_conntrack_man *, char);
+static int try_eprt(const char *, size_t, struct nf_conntrack_man *, char);
+static int try_epsv_response(const char *, size_t, struct nf_conntrack_man *,
+                            char);
+
+static struct ftp_search {
+       enum ip_conntrack_dir dir;
+       const char *pattern;
+       size_t plen;
+       char skip;
+       char term;
+       enum ip_ct_ftp_type ftptype;
+       int (*getnum)(const char *, size_t, struct nf_conntrack_man *, char);
+} search[] = {
+       {
+               IP_CT_DIR_ORIGINAL,
+               "PORT", sizeof("PORT") - 1, ' ', '\r',
+               IP_CT_FTP_PORT,
+               try_rfc959,
+       },
+       {
+               IP_CT_DIR_REPLY,
+               "227 ", sizeof("227 ") - 1, '(', ')',
+               IP_CT_FTP_PASV,
+               try_rfc959,
+       },
+       {
+               IP_CT_DIR_ORIGINAL,
+               "EPRT", sizeof("EPRT") - 1, ' ', '\r',
+               IP_CT_FTP_EPRT,
+               try_eprt,
+       },
+       {
+               IP_CT_DIR_REPLY,
+               "229 ", sizeof("229 ") - 1, '(', ')',
+               IP_CT_FTP_EPSV,
+               try_epsv_response,
+       },
+};
+
+/* This code is based on inet_pton() in glibc-2.2.4 */
+static int
+get_ipv6_addr(const char *src, size_t dlen, struct in6_addr *dst, u_int8_t term)
+{
+       static const char xdigits[] = "0123456789abcdef";
+       u_int8_t tmp[16], *tp, *endp, *colonp;
+       int ch, saw_xdigit;
+       u_int32_t val;
+       size_t clen = 0;
+
+       tp = memset(tmp, '\0', sizeof(tmp));
+       endp = tp + sizeof(tmp);
+       colonp = NULL;
+
+       /* Leading :: requires some special handling. */
+       if (*src == ':'){
+               if (*++src != ':') {
+                       DEBUGP("invalid \":\" at the head of addr\n");
+                       return 0;
+               }
+               clen++;
+       }
+
+       saw_xdigit = 0;
+       val = 0;
+       while ((clen < dlen) && (*src != term)) {
+               const char *pch;
+
+               ch = tolower(*src++);
+               clen++;
+
+                pch = strchr(xdigits, ch);
+                if (pch != NULL) {
+                        val <<= 4;
+                        val |= (pch - xdigits);
+                        if (val > 0xffff)
+                                return 0;
+
+                       saw_xdigit = 1;
+                        continue;
+                }
+               if (ch != ':') {
+                       DEBUGP("get_ipv6_addr: invalid char. \'%c\'\n", ch);
+                       return 0;
+               }
+
+               if (!saw_xdigit) {
+                       if (colonp) {
+                               DEBUGP("invalid location of \"::\".\n");
+                               return 0;
+                       }
+                       colonp = tp;
+                       continue;
+               } else if (*src == term) {
+                       DEBUGP("trancated IPv6 addr\n");
+                       return 0;
+               }
+
+               if (tp + 2 > endp)
+                       return 0;
+               *tp++ = (u_int8_t) (val >> 8) & 0xff;
+               *tp++ = (u_int8_t) val & 0xff;
+
+               saw_xdigit = 0;
+               val = 0;
+               continue;
+        }
+        if (saw_xdigit) {
+                if (tp + 2 > endp)
+                        return 0;
+                *tp++ = (u_int8_t) (val >> 8) & 0xff;
+                *tp++ = (u_int8_t) val & 0xff;
+        }
+        if (colonp != NULL) {
+                /*
+                 * Since some memmove()'s erroneously fail to handle
+                 * overlapping regions, we'll do the shift by hand.
+                 */
+                const int n = tp - colonp;
+                int i;
+
+                if (tp == endp)
+                        return 0;
+
+                for (i = 1; i <= n; i++) {
+                        endp[- i] = colonp[n - i];
+                        colonp[n - i] = 0;
+                }
+                tp = endp;
+        }
+        if (tp != endp || (*src != term))
+                return 0;
+
+        memcpy(dst->s6_addr, tmp, sizeof(dst->s6_addr));
+        return clen;
+}
+
+static int try_number(const char *data, size_t dlen, u_int32_t array[],
+                      int array_size, char sep, char term)
+{
+       u_int32_t i, len;
+
+       memset(array, 0, sizeof(array[0])*array_size);
+
+       /* Keep data pointing at next char. */
+       for (i = 0, len = 0; len < dlen && i < array_size; len++, data++) {
+               if (*data >= '0' && *data <= '9') {
+                       array[i] = array[i]*10 + *data - '0';
+               }
+               else if (*data == sep)
+                       i++;
+               else {
+                       /* Unexpected character; true if it's the
+                          terminator and we're finished. */
+                       if (*data == term && i == array_size - 1)
+                               return len;
+
+                       DEBUGP("Char %u (got %u nums) `%u' unexpected\n",
+                              len, i, *data);
+                       return 0;
+               }
+       }
+       DEBUGP("Failed to fill %u numbers separated by %c\n", array_size, sep);
+
+       return 0;
+}
+
+/* Returns 0, or length of numbers: 192,168,1,1,5,6 */
+static int try_rfc959(const char *data, size_t dlen,
+                     struct nf_conntrack_man *cmd, char term)
+{
+       int length;
+       u_int32_t array[6];
+
+       length = try_number(data, dlen, array, 6, ',', term);
+       if (length == 0)
+               return 0;
+
+       cmd->u3.ip =  htonl((array[0] << 24) | (array[1] << 16) |
+                                   (array[2] << 8) | array[3]);
+       cmd->u.tcp.port = htons((array[4] << 8) | array[5]);
+       return length;
+}
+
+/* Grab port: number up to delimiter */
+static int get_port(const char *data, int start, size_t dlen, char delim,
+                   u_int16_t *port)
+{
+       u_int16_t tmp_port = 0;
+       int i;
+
+       for (i = start; i < dlen; i++) {
+               /* Finished? */
+               if (data[i] == delim) {
+                       if (tmp_port == 0)
+                               break;
+                       *port = htons(tmp_port);
+                       DEBUGP("get_port: return %d\n", tmp_port);
+                       return i + 1;
+               }
+               else if (data[i] >= '0' && data[i] <= '9')
+                       tmp_port = tmp_port*10 + data[i] - '0';
+               else { /* Some other crap */
+                       DEBUGP("get_port: invalid char.\n");
+                       break;
+               }
+       }
+       return 0;
+}
+
+/* Returns 0, or length of numbers: |1|132.235.1.2|6275| or |2|3ffe::1|6275| */
+static int try_eprt(const char *data, size_t dlen, struct nf_conntrack_man *cmd,
+                   char term)
+{
+       char delim;
+       int length;
+
+       /* First character is delimiter, then "1" for IPv4 or "2" for IPv6,
+          then delimiter again. */
+       if (dlen <= 3) {
+               DEBUGP("EPRT: too short\n");
+               return 0;
+       }
+       delim = data[0];
+       if (isdigit(delim) || delim < 33 || delim > 126 || data[2] != delim) {
+               DEBUGP("try_eprt: invalid delimitter.\n");
+               return 0;
+       }
+
+       if ((cmd->l3num == PF_INET && data[1] != '1') ||
+           (cmd->l3num == PF_INET6 && data[1] != '2')) {
+               DEBUGP("EPRT: invalid protocol number.\n");
+               return 0;
+       }
+
+       DEBUGP("EPRT: Got %c%c%c\n", delim, data[1], delim);
+
+       if (data[1] == '1') {
+               u_int32_t array[4];
+
+               /* Now we have IP address. */
+               length = try_number(data + 3, dlen - 3, array, 4, '.', delim);
+               if (length != 0)
+                       cmd->u3.ip = htonl((array[0] << 24) | (array[1] << 16)
+                                          | (array[2] << 8) | array[3]);
+       } else {
+               /* Now we have IPv6 address. */
+               length = get_ipv6_addr(data + 3, dlen - 3,
+                                      (struct in6_addr *)cmd->u3.ip6, delim);
+       }
+
+       if (length == 0)
+               return 0;
+       DEBUGP("EPRT: Got IP address!\n");
+       /* Start offset includes initial "|1|", and trailing delimiter */
+       return get_port(data, 3 + length + 1, dlen, delim, &cmd->u.tcp.port);
+}
+
+/* Returns 0, or length of numbers: |||6446| */
+static int try_epsv_response(const char *data, size_t dlen,
+                            struct nf_conntrack_man *cmd, char term)
+{
+       char delim;
+
+       /* Three delimiters. */
+       if (dlen <= 3) return 0;
+       delim = data[0];
+       if (isdigit(delim) || delim < 33 || delim > 126
+           || data[1] != delim || data[2] != delim)
+               return 0;
+
+       return get_port(data, 3, dlen, delim, &cmd->u.tcp.port);
+}
+
+/* Return 1 for match, 0 for accept, -1 for partial. */
+static int find_pattern(const char *data, size_t dlen,
+                       const char *pattern, size_t plen,
+                       char skip, char term,
+                       unsigned int *numoff,
+                       unsigned int *numlen,
+                       struct nf_conntrack_man *cmd,
+                       int (*getnum)(const char *, size_t,
+                                     struct nf_conntrack_man *, char))
+{
+       size_t i;
+
+       DEBUGP("find_pattern `%s': dlen = %u\n", pattern, dlen);
+       if (dlen == 0)
+               return 0;
+
+       if (dlen <= plen) {
+               /* Short packet: try for partial? */
+               if (strnicmp(data, pattern, dlen) == 0)
+                       return -1;
+               else return 0;
+       }
+
+       if (strnicmp(data, pattern, plen) != 0) {
+#if 0
+               size_t i;
+
+               DEBUGP("ftp: string mismatch\n");
+               for (i = 0; i < plen; i++) {
+                       DEBUGP("ftp:char %u `%c'(%u) vs `%c'(%u)\n",
+                               i, data[i], data[i],
+                               pattern[i], pattern[i]);
+               }
+#endif
+               return 0;
+       }
+
+       DEBUGP("Pattern matches!\n");
+       /* Now we've found the constant string, try to skip
+          to the 'skip' character */
+       for (i = plen; data[i] != skip; i++)
+               if (i == dlen - 1) return -1;
+
+       /* Skip over the last character */
+       i++;
+
+       DEBUGP("Skipped up to `%c'!\n", skip);
+
+       *numoff = i;
+       *numlen = getnum(data + i, dlen - i, cmd, term);
+       if (!*numlen)
+               return -1;
+
+       DEBUGP("Match succeeded!\n");
+       return 1;
+}
+
+/* Look up to see if we're just after a \n. */
+static int find_nl_seq(u32 seq, const struct ip_ct_ftp_master *info, int dir)
+{
+       unsigned int i;
+
+       for (i = 0; i < info->seq_aft_nl_num[dir]; i++)
+               if (info->seq_aft_nl[dir][i] == seq)
+                       return 1;
+       return 0;
+}
+
+/* We don't update if it's older than what we have. */
+static void update_nl_seq(u32 nl_seq, struct ip_ct_ftp_master *info, int dir,
+                         struct sk_buff *skb)
+{
+       unsigned int i, oldest = NUM_SEQ_TO_REMEMBER;
+
+       /* Look for oldest: if we find exact match, we're done. */
+       for (i = 0; i < info->seq_aft_nl_num[dir]; i++) {
+               if (info->seq_aft_nl[dir][i] == nl_seq)
+                       return;
+
+               if (oldest == info->seq_aft_nl_num[dir]
+                   || before(info->seq_aft_nl[dir][i], oldest))
+                       oldest = i;
+       }
+
+       if (info->seq_aft_nl_num[dir] < NUM_SEQ_TO_REMEMBER) {
+               info->seq_aft_nl[dir][info->seq_aft_nl_num[dir]++] = nl_seq;
+               nf_conntrack_event_cache(IPCT_HELPINFO_VOLATILE, skb);
+       } else if (oldest != NUM_SEQ_TO_REMEMBER) {
+               info->seq_aft_nl[dir][oldest] = nl_seq;
+               nf_conntrack_event_cache(IPCT_HELPINFO_VOLATILE, skb);
+       }
+}
+
+static int help(struct sk_buff **pskb,
+               unsigned int protoff,
+               struct nf_conn *ct,
+               enum ip_conntrack_info ctinfo)
+{
+       unsigned int dataoff, datalen;
+       struct tcphdr _tcph, *th;
+       char *fb_ptr;
+       int ret;
+       u32 seq;
+       int dir = CTINFO2DIR(ctinfo);
+       unsigned int matchlen, matchoff;
+       struct ip_ct_ftp_master *ct_ftp_info = &nfct_help(ct)->help.ct_ftp_info;
+       struct nf_conntrack_expect *exp;
+       struct nf_conntrack_man cmd = {};
+
+       unsigned int i;
+       int found = 0, ends_in_nl;
+
+       /* Until there's been traffic both ways, don't look in packets. */
+       if (ctinfo != IP_CT_ESTABLISHED
+           && ctinfo != IP_CT_ESTABLISHED+IP_CT_IS_REPLY) {
+               DEBUGP("ftp: Conntrackinfo = %u\n", ctinfo);
+               return NF_ACCEPT;
+       }
+
+       th = skb_header_pointer(*pskb, protoff, sizeof(_tcph), &_tcph);
+       if (th == NULL)
+               return NF_ACCEPT;
+
+       dataoff = protoff + th->doff * 4;
+       /* No data? */
+       if (dataoff >= (*pskb)->len) {
+               DEBUGP("ftp: dataoff(%u) >= skblen(%u)\n", dataoff,
+                       (*pskb)->len);
+               return NF_ACCEPT;
+       }
+       datalen = (*pskb)->len - dataoff;
+
+       spin_lock_bh(&nf_ftp_lock);
+       fb_ptr = skb_header_pointer(*pskb, dataoff, datalen, ftp_buffer);
+       BUG_ON(fb_ptr == NULL);
+
+       ends_in_nl = (fb_ptr[datalen - 1] == '\n');
+       seq = ntohl(th->seq) + datalen;
+
+       /* Look up to see if we're just after a \n. */
+       if (!find_nl_seq(ntohl(th->seq), ct_ftp_info, dir)) {
+               /* Now if this ends in \n, update ftp info. */
+               DEBUGP("nf_conntrack_ftp_help: wrong seq pos %s(%u) or %s(%u)\n",
+                      ct_ftp_info->seq_aft_nl_num[dir] > 0 ? "" : "(UNSET)",
+                      ct_ftp_info->seq_aft_nl[dir][0],
+                      ct_ftp_info->seq_aft_nl_num[dir] > 1 ? "" : "(UNSET)",
+                      ct_ftp_info->seq_aft_nl[dir][1]);
+               ret = NF_ACCEPT;
+               goto out_update_nl;
+       }
+
+        /* Initialize IP/IPv6 addr to expected address (it's not mentioned
+           in EPSV responses) */
+       cmd.l3num = ct->tuplehash[dir].tuple.src.l3num;
+       memcpy(cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all,
+              sizeof(cmd.u3.all));
+
+       for (i = 0; i < ARRAY_SIZE(search); i++) {
+               if (search[i].dir != dir) continue;
+
+               found = find_pattern(fb_ptr, datalen,
+                                    search[i].pattern,
+                                    search[i].plen,
+                                    search[i].skip,
+                                    search[i].term,
+                                    &matchoff, &matchlen,
+                                    &cmd,
+                                    search[i].getnum);
+               if (found) break;
+       }
+       if (found == -1) {
+               /* We don't usually drop packets.  After all, this is
+                  connection tracking, not packet filtering.
+                  However, it is necessary for accurate tracking in
+                  this case. */
+               if (net_ratelimit())
+                       printk("conntrack_ftp: partial %s %u+%u\n",
+                              search[i].pattern,
+                              ntohl(th->seq), datalen);
+               ret = NF_DROP;
+               goto out;
+       } else if (found == 0) { /* No match */
+               ret = NF_ACCEPT;
+               goto out_update_nl;
+       }
+
+       DEBUGP("conntrack_ftp: match `%.*s' (%u bytes at %u)\n",
+              (int)matchlen, fb_ptr + matchoff,
+              matchlen, ntohl(th->seq) + matchoff);
+
+       exp = nf_conntrack_expect_alloc(ct);
+       if (exp == NULL) {
+               ret = NF_DROP;
+               goto out;
+       }
+
+       /* We refer to the reverse direction ("!dir") tuples here,
+        * because we're expecting something in the other direction.
+        * Doesn't matter unless NAT is happening.  */
+       exp->tuple.dst.u3 = ct->tuplehash[!dir].tuple.dst.u3;
+
+       /* Update the ftp info */
+       if ((cmd.l3num == ct->tuplehash[dir].tuple.src.l3num) &&
+           memcmp(&cmd.u3.all, &ct->tuplehash[dir].tuple.src.u3.all,
+                    sizeof(cmd.u3.all))) {
+               /* Enrico Scholz's passive FTP to partially RNAT'd ftp
+                   server: it really wants us to connect to a
+                   different IP address.  Simply don't record it for
+                   NAT. */
+               if (cmd.l3num == PF_INET) {
+                       DEBUGP("conntrack_ftp: NOT RECORDING: " NIPQUAD_FMT " != " NIPQUAD_FMT "\n",
+                              NIPQUAD(cmd.u3.ip),
+                              NIPQUAD(ct->tuplehash[dir].tuple.src.u3.ip));
+               } else {
+                       DEBUGP("conntrack_ftp: NOT RECORDING: " NIP6_FMT " != " NIP6_FMT "\n",
+                              NIP6(*((struct in6_addr *)cmd.u3.ip6)),
+                              NIP6(*((struct in6_addr *)ct->tuplehash[dir]
+                                                       .tuple.src.u3.ip6)));
+               }
+
+               /* Thanks to Cristiano Lincoln Mattos
+                  <lincoln@cesar.org.br> for reporting this potential
+                  problem (DMZ machines opening holes to internal
+                  networks, or the packet filter itself). */
+               if (!loose) {
+                       ret = NF_ACCEPT;
+                       goto out_put_expect;
+               }
+               memcpy(&exp->tuple.dst.u3, &cmd.u3.all,
+                      sizeof(exp->tuple.dst.u3));
+       }
+
+       exp->tuple.src.u3 = ct->tuplehash[!dir].tuple.src.u3;
+       exp->tuple.src.l3num = cmd.l3num;
+       exp->tuple.src.u.tcp.port = 0;
+       exp->tuple.dst.u.tcp.port = cmd.u.tcp.port;
+       exp->tuple.dst.protonum = IPPROTO_TCP;
+
+       exp->mask = (struct nf_conntrack_tuple)
+                   { .src = { .l3num = 0xFFFF,
+                              .u = { .tcp = { 0 }},
+                            },
+                     .dst = { .protonum = 0xFF,
+                              .u = { .tcp = { 0xFFFF }},
+                            },
+                   };
+       if (cmd.l3num == PF_INET) {
+               exp->mask.src.u3.ip = 0xFFFFFFFF;
+               exp->mask.dst.u3.ip = 0xFFFFFFFF;
+       } else {
+               memset(exp->mask.src.u3.ip6, 0xFF,
+                      sizeof(exp->mask.src.u3.ip6));
+               memset(exp->mask.dst.u3.ip6, 0xFF,
+                      sizeof(exp->mask.src.u3.ip6));
+       }
+
+       exp->expectfn = NULL;
+       exp->flags = 0;
+
+       /* Now, NAT might want to mangle the packet, and register the
+        * (possibly changed) expectation itself. */
+       if (nf_nat_ftp_hook)
+               ret = nf_nat_ftp_hook(pskb, ctinfo, search[i].ftptype,
+                                     matchoff, matchlen, exp, &seq);
+       else {
+               /* Can't expect this?  Best to drop packet now. */
+               if (nf_conntrack_expect_related(exp) != 0)
+                       ret = NF_DROP;
+               else
+                       ret = NF_ACCEPT;
+       }
+
+out_put_expect:
+       nf_conntrack_expect_put(exp);
+
+out_update_nl:
+       /* Now if this ends in \n, update ftp info.  Seq may have been
+        * adjusted by NAT code. */
+       if (ends_in_nl)
+               update_nl_seq(seq, ct_ftp_info, dir, *pskb);
+ out:
+       spin_unlock_bh(&nf_ftp_lock);
+       return ret;
+}
+
+static struct nf_conntrack_helper ftp[MAX_PORTS][2];
+static char ftp_names[MAX_PORTS][2][sizeof("ftp-65535")];
+
+/* don't make this __exit, since it's called from __init ! */
+static void nf_conntrack_ftp_fini(void)
+{
+       int i, j;
+       for (i = 0; i < ports_c; i++) {
+               for (j = 0; j < 2; j++) {
+                       if (ftp[i][j].me == NULL)
+                               continue;
+
+                       DEBUGP("nf_ct_ftp: unregistering helper for pf: %d "
+                              "port: %d\n",
+                               ftp[i][j].tuple.src.l3num, ports[i]);
+                       nf_conntrack_helper_unregister(&ftp[i][j]);
+               }
+       }
+
+       kfree(ftp_buffer);
+}
+
+static int __init nf_conntrack_ftp_init(void)
+{
+       int i, j = -1, ret = 0;
+       char *tmpname;
+
+       ftp_buffer = kmalloc(65536, GFP_KERNEL);
+       if (!ftp_buffer)
+               return -ENOMEM;
+
+       if (ports_c == 0)
+               ports[ports_c++] = FTP_PORT;
+
+       /* FIXME should be configurable whether IPv4 and IPv6 FTP connections
+                are tracked or not - YK */
+       for (i = 0; i < ports_c; i++) {
+               ftp[i][0].tuple.src.l3num = PF_INET;
+               ftp[i][1].tuple.src.l3num = PF_INET6;
+               for (j = 0; j < 2; j++) {
+                       ftp[i][j].tuple.src.u.tcp.port = htons(ports[i]);
+                       ftp[i][j].tuple.dst.protonum = IPPROTO_TCP;
+                       ftp[i][j].mask.src.u.tcp.port = 0xFFFF;
+                       ftp[i][j].mask.dst.protonum = 0xFF;
+                       ftp[i][j].max_expected = 1;
+                       ftp[i][j].timeout = 5 * 60;     /* 5 Minutes */
+                       ftp[i][j].me = THIS_MODULE;
+                       ftp[i][j].help = help;
+                       tmpname = &ftp_names[i][j][0];
+                       if (ports[i] == FTP_PORT)
+                               sprintf(tmpname, "ftp");
+                       else
+                               sprintf(tmpname, "ftp-%d", ports[i]);
+                       ftp[i][j].name = tmpname;
+
+                       DEBUGP("nf_ct_ftp: registering helper for pf: %d "
+                              "port: %d\n",
+                               ftp[i][j].tuple.src.l3num, ports[i]);
+                       ret = nf_conntrack_helper_register(&ftp[i][j]);
+                       if (ret) {
+                               printk("nf_ct_ftp: failed to register helper "
+                                      " for pf: %d port: %d\n",
+                                       ftp[i][j].tuple.src.l3num, ports[i]);
+                               nf_conntrack_ftp_fini();
+                               return ret;
+                       }
+               }
+       }
+
+       return 0;
+}
+
+module_init(nf_conntrack_ftp_init);
+module_exit(nf_conntrack_ftp_fini);