packet-ftp.c

   1 /* packet-ftp.c
   2  * Routines for ftp packet dissection
   3  * Copyright 1999, Richard Sharpe <rsharpe@ns.aus.com>
   4  * Copyright 2001, Juan Toledo <toledo@users.sourceforge.net> (Passive FTP)
   5  *
   6  * $Id: packet-ftp.c,v 1.54 2003/10/08 11:33:19 jmayer Exp $
   7  *
   8  * Ethereal - Network traffic analyzer
   9  * By Gerald Combs <gerald@ethereal.com>
  10  * Copyright 1998 Gerald Combs
  11  *
  12  * Copied from packet-pop.c
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License
  16  * as published by the Free Software Foundation; either version 2
  17  * of the License, or (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, write to the Free Software
  26  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  27  */
  28
  29 #ifdef HAVE_CONFIG_H
  30 # include "config.h"
  31 #endif
  32
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <ctype.h>
  36
  37 #include <string.h>
  38 #include <glib.h>
  39 #include <epan/packet.h>
  40 #include <epan/strutil.h>
  41 #include <epan/conversation.h>
  42
  43 static int proto_ftp = -1;
  44 static int proto_ftp_data = -1;
  45 static int hf_ftp_response = -1;
  46 static int hf_ftp_request = -1;
  47 static int hf_ftp_request_command = -1;
  48 static int hf_ftp_request_arg = -1;
  49 static int hf_ftp_response_code = -1;
  50 static int hf_ftp_response_arg = -1;
  51 static int hf_ftp_pasv_ip = -1 ;
  52 static int hf_ftp_pasv_port = -1;
  53 static int hf_ftp_pasv_nat = -1;
  54 static int hf_ftp_active_ip = -1;
  55 static int hf_ftp_active_port = -1;
  56 static int hf_ftp_active_nat = -1;
  57
  58 static gint ett_ftp = -1;
  59 static gint ett_ftp_reqresp = -1;
  60 static gint ett_ftp_data = -1;
  61
  62 static dissector_handle_t ftpdata_handle;
  63
  64 #define TCP_PORT_FTPDATA                20
  65 #define TCP_PORT_FTP                    21
  66
  67 static const value_string response_table[] = {
  68         { 110, "Restart marker reply" },
  69         { 120, "Service ready in nnn minutes" },
  70         { 125, "Data connection already open; transfer starting" },
  71         { 150, "File status okay; about to open data connection" },
  72         { 200, "Command okay" },
  73         { 202, "Command not implemented, superfluous at this site" },
  74         { 211, "System status, or system help reply" },
  75         { 212, "Directory status" },
  76         { 213, "File status" },
  77         { 214, "Help message" },
  78         { 215, "NAME system type" },
  79         { 220, "Service ready for new user" },
  80         { 221, "Service closing control connection" },
  81         { 225, "Data connection open; no transfer in progress" },
  82         { 226, "Closing data connection" },
  83         { 227, "Entering Passive Mode" },
  84         { 230, "User logged in, proceed" },
  85         { 250, "Requested file action okay, completed" },
  86         { 257, "PATHNAME created" },
  87         { 331, "User name okay, need password" },
  88         { 332, "Need account for login" },
  89         { 350, "Requested file action pending further information" },
  90         { 421, "Service not available, closing control connection" },
  91         { 425, "Can't open data connection" },
  92         { 426, "Connection closed; transfer aborted" },
  93         { 450, "Requested file action not taken" },
  94         { 451, "Requested action aborted: local error in processing" },
  95         { 452, "Requested action not taken. Insufficient storage space in system" },
  96         { 500, "Syntax error, command unrecognized" },
  97         { 501, "Syntax error in parameters or arguments" },
  98         { 502, "Command not implemented" },
  99         { 503, "Bad sequence of commands" },
 100         { 504, "Command not implemented for that parameter" },
 101         { 530, "Not logged in" },
 102         { 532, "Need account for storing files" },
 103         { 550, "Requested action not taken: File unavailable" },
 104         { 551, "Requested action aborted: page type unknown" },
 105         { 552, "Requested file action aborted: Exceeded storage allocation" },
 106         { 553, "Requested action not taken: File name not allowed" },
 107         { 0,   NULL }
 108 };
 109
 110 static void
 111 dissect_ftpdata(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
 112
 113 /*
 114  * Parse the address and port information in a PORT command or in the
 115  * response to a PASV command.  Return TRUE if we found an address and
 116  * port, and supply the address and port; return FALSE if we didn't find
 117  * them.
 118  *
 119  * We ignore the IP address in the reply, and use the address from which
 120  * the request came.
 121  *
 122  * XXX - are there cases where they differ?  What if the FTP server is
 123  * behind a NAT box, so that the address it puts into the reply isn't
 124  * the address at which you should contact it?  Do all NAT boxes detect
 125  * FTP PASV replies and rewrite the address?  (I suspect not.)
 126  *
 127  * RFC 959 doesn't say much about the syntax of the 227 reply.
 128  *
 129  * A proposal from Dan Bernstein at
 130  *
 131  *      http://cr.yp.to/ftp/retr.html
 132  *
 133  * "recommend[s] that clients use the following strategy to parse the
 134  * response line: look for the first digit after the initial space; look
 135  * for the fourth comma after that digit; read two (possibly negative)
 136  * integers, separated by a comma; the TCP port number is p1*256+p2, where
 137  * p1 is the first integer modulo 256 and p2 is the second integer modulo
 138  * 256."
 139  *
 140  * wget 1.5.3 looks for a digit, although it doesn't handle negative
 141  * integers.
 142  *
 143  * The FTP code in the source of the cURL library, at
 144  *
 145  *      http://curl.haxx.se/lxr/source/lib/ftp.c
 146  *
 147  * says that cURL "now scans for a sequence of six comma-separated numbers
 148  * and will take them as IP+port indicators"; it loops, doing "sscanf"s
 149  * looking for six numbers separated by commas, stepping the start pointer
 150  * in the scanf one character at a time - i.e., it tries rather exhaustively.
 151  *
 152  * An optimization would be to scan for a digit, and start there, and if
 153  * the scanf doesn't find six values, scan for the next digit and try
 154  * again; this will probably succeed on the first try.
 155  *
 156  * The cURL code also says that "found reply-strings include":
 157  *
 158  *      "227 Entering Passive Mode (127,0,0,1,4,51)"
 159  *      "227 Data transfer will passively listen to 127,0,0,1,4,51"
 160  *      "227 Entering passive mode. 127,0,0,1,4,51"
 161  *
 162  * so it appears that you can't assume there are parentheses around
 163  * the address and port number.
 164  */
 165 static gboolean
 166 parse_port_pasv(const guchar *line, int linelen, guint32 *ftp_ip,
 167     guint16 *ftp_port)
 168 {
 169         char *args;
 170         char *p;
 171         guchar c;
 172         int i;
 173         int address[4], port[2];
 174         gboolean ret = FALSE;
 175
 176         /*
 177          * Copy the rest of the line into a null-terminated buffer.
 178          */
 179         args = g_malloc(linelen + 1);
 180         memcpy(args, line, linelen);
 181         args[linelen] = '\0';
 182         p = args;
 183
 184         for (;;) {
 185                 /*
 186                  * Look for a digit.
 187                  */
 188                 while ((c = *p) != '\0' && !isdigit(c))
 189                         p++;
 190
 191                 if (*p == '\0') {
 192                         /*
 193                          * We ran out of text without finding anything.
 194                          */
 195                         break;
 196                 }
 197
 198                 /*
 199                  * See if we have six numbers.
 200                  */
 201                 i = sscanf(p, "%d,%d,%d,%d,%d,%d",
 202                     &address[0], &address[1], &address[2], &address[3],
 203                     &port[0], &port[1]);
 204                 if (i == 6) {
 205                         /*
 206                          * We have a winner!
 207                          */
 208                         *ftp_port = ((port[0] & 0xFF)<<8) | (port[1] & 0xFF);
 209                         *ftp_ip = g_htonl((address[0] << 24) | (address[1] <<16) | (address[2] <<8) | address[3]);
 210                         ret = TRUE;
 211                         break;
 212                 }
 213
 214                 /*
 215                  * Well, that didn't work.  Skip the first number we found,
 216                  * and keep trying.
 217                  */
 218                 while ((c = *p) != '\0' && isdigit(c))
 219                         p++;
 220         }
 221
 222         g_free(args);
 223         return ret;
 224 }
 225
 226 static void
 227 dissect_ftp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 228 {
 229         gboolean        is_request;
 230         proto_tree      *ftp_tree = NULL;
 231         proto_tree      *reqresp_tree = NULL;
 232         proto_item      *ti;
 233         gint            offset = 0;
 234         const guchar    *line;
 235         guint32         code;
 236         gchar           code_str[4];
 237         gboolean        is_port_request = FALSE;
 238         gboolean        is_pasv_response = FALSE;
 239         gint            next_offset;
 240         int             linelen;
 241         int             tokenlen;
 242         const guchar    *next_token;
 243         guint32         pasv_ip;
 244         guint32         ftp_ip;
 245         guint16         ftp_port;
 246         address         ftp_ip_address;
 247         gboolean        ftp_nat;
 248         conversation_t  *conversation;
 249
 250         ftp_ip_address = pinfo->src;
 251
 252         if (pinfo->match_port == pinfo->destport)
 253                 is_request = TRUE;
 254         else
 255                 is_request = FALSE;
 256
 257         if (check_col(pinfo->cinfo, COL_PROTOCOL))
 258                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "FTP");
 259
 260         /*
 261          * Find the end of the first line.
 262          *
 263          * Note that "tvb_find_line_end()" will return a value that is
 264          * not longer than what's in the buffer, so the "tvb_get_ptr()"
 265          * call won't throw an exception.
 266          */
 267         linelen = tvb_find_line_end(tvb, offset, -1, &next_offset, FALSE);
 268         line = tvb_get_ptr(tvb, offset, linelen);
 269
 270         if (check_col(pinfo->cinfo, COL_INFO)) {
 271                 /*
 272                  * Put the first line from the buffer into the summary
 273                  * (but leave out the line terminator).
 274                  */
 275                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s: %s",
 276                     is_request ? "Request" : "Response",
 277                     format_text(line, linelen));
 278         }
 279
 280         if (tree) {
 281                 ti = proto_tree_add_item(tree, proto_ftp, tvb, offset, -1,
 282                     FALSE);
 283                 ftp_tree = proto_item_add_subtree(ti, ett_ftp);
 284
 285                 if (is_request) {
 286                         proto_tree_add_boolean_hidden(ftp_tree,
 287                             hf_ftp_request, tvb, 0, 0, TRUE);
 288                         proto_tree_add_boolean_hidden(ftp_tree,
 289                             hf_ftp_response, tvb, 0, 0, FALSE);
 290                 } else {
 291                         proto_tree_add_boolean_hidden(ftp_tree,
 292                             hf_ftp_request, tvb, 0, 0, FALSE);
 293                         proto_tree_add_boolean_hidden(ftp_tree,
 294                             hf_ftp_response, tvb, 0, 0, TRUE);
 295                 }
 296
 297                 /*
 298                  * Put the line into the protocol tree.
 299                  */
 300                 ti = proto_tree_add_text(ftp_tree, tvb, offset,
 301                     next_offset - offset, "%s",
 302                     tvb_format_text(tvb, offset, next_offset - offset));
 303                 reqresp_tree = proto_item_add_subtree(ti, ett_ftp_reqresp);
 304         }
 305
 306         if (is_request) {
 307                 /*
 308                  * Extract the first token, and, if there is a first
 309                  * token, add it as the request.
 310                  */
 311                 tokenlen = get_token_len(line, line + linelen, &next_token);
 312                 if (tokenlen != 0) {
 313                         if (tree) {
 314                                 proto_tree_add_item(reqresp_tree,
 315                                     hf_ftp_request_command, tvb, offset,
 316                                     tokenlen, FALSE);
 317                         }
 318                         if (strncmp(line, "PORT", tokenlen) == 0)
 319                                 is_port_request = TRUE;
 320                 }
 321         } else {
 322                 /*
 323                  * This is a response; the response code is 3 digits,
 324                  * followed by a space or hyphen, possibly followed by
 325                  * text.
 326                  *
 327                  * If the line doesn't start with 3 digits, it's part of
 328                  * a continuation.
 329                  *
 330                  * XXX - keep track of state in the first pass, and
 331                  * treat non-continuation lines not beginning with digits
 332                  * as errors?
 333                  */
 334                 if (linelen >= 3 && isdigit(line[0]) && isdigit(line[1])
 335                     && isdigit(line[2])) {
 336                         /*
 337                          * One-line reply, or first or last line
 338                          * of a multi-line reply.
 339                          */
 340                         tvb_get_nstringz0(tvb, offset, sizeof(code_str), code_str);
 341                         code = strtoul(code_str, NULL, 10);
 342
 343                         if (tree) {
 344                                 proto_tree_add_uint(reqresp_tree,
 345                                     hf_ftp_response_code, tvb, offset, 3, code);
 346                         }
 347
 348                         /*
 349                          * See if it's a passive-mode response.
 350                          *
 351                          * XXX - check for "229" responses to EPSV
 352                          * commands, to handle IPv6, as per RFC 2428?
 353                          *
 354                          * XXX - does anybody do FOOBAR, as per RFC
 355                          * 1639, or has that been supplanted by RFC 2428?
 356                          */
 357                         if (code == 227)
 358                                 is_pasv_response = TRUE;
 359
 360                         /*
 361                          * Skip the 3 digits and, if present, the
 362                          * space or hyphen.
 363                          */
 364                         if (linelen >= 4)
 365                                 next_token = line + 4;
 366                         else
 367                                 next_token = line + linelen;
 368                 } else {
 369                         /*
 370                          * Line doesn't start with 3 digits; assume it's
 371                          * a line in the middle of a multi-line reply.
 372                          */
 373                         next_token = line;
 374                 }
 375         }
 376         offset += next_token - line;
 377         linelen -= next_token - line;
 378         line = next_token;
 379
 380         if (tree) {
 381                 /*
 382                  * Add the rest of the first line as request or
 383                  * reply data.
 384                  */
 385                 if (linelen != 0) {
 386                         if (is_request) {
 387                                 proto_tree_add_item(reqresp_tree,
 388                                     hf_ftp_request_arg, tvb, offset,
 389                                     linelen, FALSE);
 390                         } else {
 391                                 proto_tree_add_item(reqresp_tree,
 392                                     hf_ftp_response_arg, tvb, offset,
 393                                     linelen, FALSE);
 394                         }
 395                 }
 396                 offset = next_offset;
 397         }
 398
 399         /*
 400          * If this is a PORT request or a PASV response, handle it.
 401          */
 402         if (is_port_request) {
 403                 if (parse_port_pasv(line, linelen, &ftp_ip,
 404                     &ftp_port)) {
 405                         if (tree) {
 406                                 proto_tree_add_ipv4(reqresp_tree,
 407                                     hf_ftp_active_ip, tvb, 0, 0,
 408                                     ftp_ip);
 409                                 proto_tree_add_uint(reqresp_tree,
 410                                     hf_ftp_active_port, tvb, 0, 0,
 411                                     ftp_port);
 412                         }
 413                         SET_ADDRESS(&ftp_ip_address, AT_IPv4, 4,
 414                             (const guint8 *)&ftp_ip);
 415                         ftp_nat = !ADDRESSES_EQUAL(&pinfo->src,
 416                             &ftp_ip_address);
 417                         if (ftp_nat) {
 418                                 if (tree) {
 419                                         proto_tree_add_boolean(
 420                                             reqresp_tree,
 421                                             hf_ftp_active_nat, tvb,
 422                                             0, 0, ftp_nat);
 423                                 }
 424                         }
 425                 }
 426         }
 427
 428         if (is_pasv_response) {
 429                 if (linelen != 0) {
 430                         /*
 431                          * This frame contains a PASV response; set up a
 432                          * conversation for the data.
 433                          */
 434                         if (parse_port_pasv(line, linelen, &pasv_ip,
 435                             &ftp_port)) {
 436                                 if (tree) {
 437                                         proto_tree_add_ipv4(reqresp_tree,
 438                                             hf_ftp_pasv_ip, tvb, 0, 0, pasv_ip);
 439                                         proto_tree_add_uint(reqresp_tree,
 440                                             hf_ftp_pasv_port, tvb, 0, 0,
 441                                             ftp_port);
 442                                 }
 443                                 SET_ADDRESS(&ftp_ip_address, AT_IPv4, 4,
 444                                     (const guint8 *)&pasv_ip);
 445                                 ftp_nat = !ADDRESSES_EQUAL(&pinfo->src,
 446                                     &ftp_ip_address);
 447                                 if (ftp_nat) {
 448                                         if (tree) {
 449                                                 proto_tree_add_boolean(reqresp_tree,
 450                                                     hf_ftp_pasv_nat, tvb, 0, 0,
 451                                                     ftp_nat);
 452                                         }
 453                                 }
 454
 455                                 /*
 456                                  * We use "ftp_ip_address", so that if
 457                                  * we're NAT'd we look for the un-NAT'd
 458                                  * connection.
 459                                  *
 460                                  * XXX - should this call to
 461                                  * "find_conversation()" just use
 462                                  * "ftp_ip_address" and "server_port", and
 463                                  * wildcard everything else?
 464                                  */
 465                                 conversation = find_conversation(&ftp_ip_address,
 466                                     &pinfo->dst, PT_TCP, ftp_port, 0,
 467                                     NO_PORT_B);
 468                                 if (conversation == NULL) {
 469                                         /*
 470                                          * XXX - should this call to
 471                                          * "conversation_new()" just use
 472                                          * "ftp_ip_address" and "server_port",
 473                                          * and wildcard everything else?
 474                                          *
 475                                          * XXX - what if we did find a
 476                                          * conversation?  As we create it
 477                                          * only on the first pass through
 478                                          * the packets, if we find one, it's
 479                                          * presumably an unrelated conversation.
 480                                          * Should we remove the old one from
 481                                          * the hash table and put this one in
 482                                          * its place?  Can the conversation
 483                                          * code handle conversations not in
 484                                          * the hash table?  Or should we
 485                                          * make conversations support
 486                                          * start and end frames, as circuits
 487                                          * do, and treat this as an indication
 488                                          * that one conversation was closed
 489                                          * and a new one was opened?
 490                                          */
 491                                         conversation = conversation_new(
 492                                             &ftp_ip_address, &pinfo->dst,
 493                                             PT_TCP, ftp_port, 0, NO_PORT2);
 494                                         conversation_set_dissector(conversation,
 495                                             ftpdata_handle);
 496                                 }
 497                         }
 498                 }
 499         }
 500
 501         if (tree) {
 502                 /*
 503                  * Show the rest of the request or response as text,
 504                  * a line at a time.
 505                  * XXX - only if there's a continuation indicator?
 506                  */
 507                 while (tvb_offset_exists(tvb, offset)) {
 508                         /*
 509                          * Find the end of the line.
 510                          */
 511                         linelen = tvb_find_line_end(tvb, offset, -1,
 512                             &next_offset, FALSE);
 513
 514                         /*
 515                          * Put this line.
 516                          */
 517                         proto_tree_add_text(ftp_tree, tvb, offset,
 518                             next_offset - offset, "%s",
 519                             tvb_format_text(tvb, offset, next_offset - offset));
 520                         offset = next_offset;
 521                 }
 522         }
 523 }
 524
 525 static void
 526 dissect_ftpdata(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 527 {
 528         proto_tree      *ti, *ftp_data_tree;
 529         int             data_length;
 530
 531         if (check_col(pinfo->cinfo, COL_PROTOCOL))
 532                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "FTP-DATA");
 533
 534         if (check_col(pinfo->cinfo, COL_INFO)) {
 535                 col_add_fstr(pinfo->cinfo, COL_INFO, "FTP Data: %u bytes",
 536                     tvb_reported_length(tvb));
 537         }
 538
 539         if (tree) {
 540                 data_length = tvb_length(tvb);
 541
 542                 ti = proto_tree_add_item(tree, proto_ftp_data, tvb, 0, -1,
 543                     FALSE);
 544                 ftp_data_tree = proto_item_add_subtree(ti, ett_ftp_data);
 545
 546                 /*
 547                  * XXX - if this is binary data, it'll produce
 548                  * a *really* long line.
 549                  */
 550                 proto_tree_add_text(ftp_data_tree, tvb, 0, data_length,
 551                     "FTP Data: %s", tvb_format_text(tvb, 0, data_length));
 552         }
 553 }
 554
 555 void
 556 proto_register_ftp(void)
 557 {
 558     static hf_register_info hf[] = {
 559     { &hf_ftp_response,
 560       { "Response",           "ftp.response",
 561         FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 562         "TRUE if FTP response", HFILL }},
 563
 564     { &hf_ftp_request,
 565       { "Request",            "ftp.request",
 566         FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 567         "TRUE if FTP request", HFILL }},
 568
 569     { &hf_ftp_request_command,
 570       { "Request command",    "ftp.request.command",
 571         FT_STRING,  BASE_NONE, NULL, 0x0,
 572         "", HFILL }},
 573
 574     { &hf_ftp_request_arg,
 575       { "Request arg",        "ftp.request.arg",
 576         FT_STRING,  BASE_NONE, NULL, 0x0,
 577         "", HFILL }},
 578
 579     { &hf_ftp_response_code,
 580       { "Response code",      "ftp.response.code",
 581         FT_UINT32,   BASE_DEC, VALS(response_table), 0x0,
 582         "", HFILL }},
 583
 584     { &hf_ftp_response_arg,
 585       { "Response arg",      "ftp.response.arg",
 586         FT_STRING,  BASE_NONE, NULL, 0x0,
 587         "", HFILL }},
 588
 589     { &hf_ftp_pasv_ip,
 590       { "Passive IP address", "ftp.passive.ip",
 591         FT_IPv4, BASE_NONE, NULL,0x0,
 592         "Passive IP address (check NAT)", HFILL}},
 593
 594     { &hf_ftp_pasv_port,
 595       { "Passive port", "ftp.passive.port",
 596        FT_UINT16, BASE_DEC, NULL,0x0,
 597         "Passive FTP server port", HFILL }},
 598
 599     { &hf_ftp_pasv_nat,
 600       {"Passive IP NAT", "ftp.passive.nat",
 601         FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 602         "NAT is active SIP and passive IP different", HFILL }},
 603
 604     { &hf_ftp_active_ip,
 605       { "Active IP address", "ftp.active.cip",
 606         FT_IPv4, BASE_NONE, NULL, 0x0,
 607         "Active FTP client IP address", HFILL }},
 608
 609     { &hf_ftp_active_port,
 610       {"Active port", "ftp.active.port",
 611         FT_UINT16, BASE_DEC, NULL, 0x0,
 612         "Active FTP client port", HFILL }},
 613
 614     { &hf_ftp_active_nat,
 615       { "Active IP NAT", "ftp.active.nat",
 616         FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 617         "NAT is active", HFILL}}
 618
 619   };
 620   static gint *ett[] = {
 621     &ett_ftp,
 622     &ett_ftp_reqresp,
 623     &ett_ftp_data,
 624   };
 625
 626   proto_ftp = proto_register_protocol("File Transfer Protocol (FTP)", "FTP",
 627                                       "ftp");
 628   proto_ftp_data = proto_register_protocol("FTP Data", "FTP-DATA", "ftp-data");
 629   proto_register_field_array(proto_ftp, hf, array_length(hf));
 630   proto_register_subtree_array(ett, array_length(ett));
 631
 632   ftpdata_handle = create_dissector_handle(dissect_ftpdata, proto_ftp_data);
 633 }
 634
 635 void
 636 proto_reg_handoff_ftp(void)
 637 {
 638   dissector_handle_t ftpdata_handle, ftp_handle;
 639
 640   ftpdata_handle = create_dissector_handle(dissect_ftpdata, proto_ftp_data);
 641   dissector_add("tcp.port", TCP_PORT_FTPDATA, ftpdata_handle);
 642   ftp_handle = create_dissector_handle(dissect_ftp, proto_ftp);
 643   dissector_add("tcp.port", TCP_PORT_FTP, ftp_handle);
 644 }