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)
6 * $Id: packet-ftp.c,v 1.48 2002/08/02 23:35:49 jmayer Exp $
8 * Ethereal - Network traffic analyzer
9 * By Gerald Combs <gerald@ethereal.com>
10 * Copyright 1998 Gerald Combs
12 * Copied from packet-pop.c
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.
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.
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.
39 #include <epan/packet.h>
40 #include <epan/strutil.h>
41 #include <epan/conversation.h>
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;
52 static gint ett_ftp = -1;
53 static gint ett_ftp_data = -1;
55 static dissector_handle_t ftpdata_handle;
57 #define TCP_PORT_FTPDATA 20
58 #define TCP_PORT_FTP 21
61 dissect_ftpdata(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
64 * Handle a response to a PASV command.
66 * We ignore the IP address in the reply, and use the address from which
69 * XXX - are there cases where they differ? What if the FTP server is
70 * behind a NAT box, so that the address it puts into the reply isn't
71 * the address at which you should contact it? Do all NAT boxes detect
72 * FTP PASV replies and rewrite the address? (I suspect not.)
74 * RFC 959 doesn't say much about the syntax of the 227 reply.
76 * A proposal from Dan Bernstein at
78 * http://cr.yp.to/ftp/retr.html
80 * "recommend[s] that clients use the following strategy to parse the
81 * response line: look for the first digit after the initial space; look
82 * for the fourth comma after that digit; read two (possibly negative)
83 * integers, separated by a comma; the TCP port number is p1*256+p2, where
84 * p1 is the first integer modulo 256 and p2 is the second integer modulo
87 * wget 1.5.3 looks for a digit, although it doesn't handle negative
90 * The FTP code in the source of the cURL library, at
92 * http://curl.haxx.se/lxr/source/lib/ftp.c
94 * says that cURL "now scans for a sequence of six comma-separated numbers
95 * and will take them as IP+port indicators"; it loops, doing "sscanf"s
96 * looking for six numbers separated by commas, stepping the start pointer
97 * in the scanf one character at a time - i.e., it tries rather exhaustively.
99 * An optimization would be to scan for a digit, and start there, and if
100 * the scanf doesn't find six values, scan for the next digit and try
101 * again; this will probably succeed on the first try.
103 * The cURL code also says that "found reply-strings include":
105 * "227 Entering Passive Mode (127,0,0,1,4,51)"
106 * "227 Data transfer will passively listen to 127,0,0,1,4,51"
107 * "227 Entering passive mode. 127,0,0,1,4,51"
109 * so it appears that you can't assume there are parentheses around
110 * the address and port number.
113 handle_pasv_response(const guchar *line, int linelen, packet_info *pinfo)
119 int address[4], port[2];
121 conversation_t *conversation;
124 * Copy the rest of the line into a null-terminated buffer.
126 args = g_malloc(linelen + 1);
127 memcpy(args, line, linelen);
128 args[linelen] = '\0';
135 while ((c = *p) != '\0' && !isdigit(c))
140 * We ran out of text without finding anything.
146 * See if we have six numbers.
148 i = sscanf(p, "%d,%d,%d,%d,%d,%d",
149 &address[0], &address[1], &address[2], &address[3],
154 * Set up a conversation, to be dissected as FTP data.
156 server_port = ((port[0] & 0xFF)<<8) | (port[1] & 0xFF);
159 * XXX - should this call to "find_conversation()"
160 * just use "pinfo->src" and "server_port", and
161 * wildcard everything else?
163 conversation = find_conversation(&pinfo->src,
164 &pinfo->dst, PT_TCP, server_port, 0, NO_PORT_B);
165 if (conversation == NULL) {
167 * XXX - should this call to
168 * "conversation_new()" just use "pinfo->src"
169 * and "server_port", and wildcard everything
172 * XXX - what if we did find a conversation?
173 * As we create it only on the first pass
174 * through the packets, if we find one, it's
175 * presumably an unrelated conversation.
176 * Should we remove the old one from the hash
177 * table and put this one in its place?
178 * Can the conversaton code handle
179 * conversations not in the hash table?
181 conversation = conversation_new(&pinfo->src,
182 &pinfo->dst, PT_TCP, server_port, 0,
184 conversation_set_dissector(conversation,
191 * Well, that didn't work. Skip the first number we found,
194 while ((c = *p) != '\0' && isdigit(c))
202 dissect_ftp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
205 proto_tree *ftp_tree = NULL;
210 gboolean is_pasv_response = FALSE;
214 const guchar *next_token;
216 if (pinfo->match_port == pinfo->destport)
221 if (check_col(pinfo->cinfo, COL_PROTOCOL))
222 col_set_str(pinfo->cinfo, COL_PROTOCOL, "FTP");
225 * Find the end of the first line.
227 * Note that "tvb_find_line_end()" will return a value that is
228 * not longer than what's in the buffer, so the "tvb_get_ptr()"
229 * call won't throw an exception.
231 linelen = tvb_find_line_end(tvb, offset, -1, &next_offset, FALSE);
232 line = tvb_get_ptr(tvb, offset, linelen);
234 if (check_col(pinfo->cinfo, COL_INFO)) {
236 * Put the first line from the buffer into the summary
237 * (but leave out the line terminator).
239 col_add_fstr(pinfo->cinfo, COL_INFO, "%s: %s",
240 is_request ? "Request" : "Response",
241 format_text(line, linelen));
245 ti = proto_tree_add_item(tree, proto_ftp, tvb, offset, -1,
247 ftp_tree = proto_item_add_subtree(ti, ett_ftp);
250 proto_tree_add_boolean_hidden(ftp_tree,
251 hf_ftp_request, tvb, 0, 0, TRUE);
252 proto_tree_add_boolean_hidden(ftp_tree,
253 hf_ftp_response, tvb, 0, 0, FALSE);
255 proto_tree_add_boolean_hidden(ftp_tree,
256 hf_ftp_request, tvb, 0, 0, FALSE);
257 proto_tree_add_boolean_hidden(ftp_tree,
258 hf_ftp_response, tvb, 0, 0, TRUE);
264 * Extract the first token, and, if there is a first
265 * token, add it as the request.
267 tokenlen = get_token_len(line, line + linelen, &next_token);
270 proto_tree_add_item(ftp_tree,
271 hf_ftp_request_command, tvb, offset,
277 * This is a response; the response code is 3 digits,
278 * followed by a space or hyphen, possibly followed by
281 * If the line doesn't start with 3 digits, it's part of
284 * XXX - keep track of state in the first pass, and
285 * treat non-continuation lines not beginning with digits
288 if (linelen >= 3 && isdigit(line[0]) && isdigit(line[1])
289 && isdigit(line[2])) {
291 * One-line reply, or first or last line
292 * of a multi-line reply.
294 code = (line[0] - '0')*100 + (line[1] - '0')*10
297 proto_tree_add_uint(ftp_tree,
298 hf_ftp_response_code, tvb, offset, 3, code);
303 * See if it's a passive-mode response.
305 * XXX - check for "229" responses to EPSV
306 * commands, to handle IPv6, as per RFC 2428?
308 * XXX - does anybody do FOOBAR, as per RFC
309 * 1639, or has that been supplanted by RFC 2428?
312 is_pasv_response = TRUE;
315 * Skip the 3 digits and, if present, the
319 next_token = line + 4;
321 next_token = line + linelen;
324 * Line doesn't start with 3 digits; assume it's
325 * a line in the middle of a multi-line reply.
330 offset += next_token - line;
331 linelen -= next_token - line;
335 * If this is a PASV response, handle it if we haven't
336 * already processed this frame.
338 if (!pinfo->fd->flags.visited && is_pasv_response) {
341 * We haven't processed this frame, and it contains
342 * a PASV response; set up a conversation for the
345 handle_pasv_response(line, linelen, pinfo);
351 * Add the rest of the first line as request or
356 proto_tree_add_item(ftp_tree,
357 hf_ftp_request_arg, tvb, offset,
360 proto_tree_add_item(ftp_tree,
361 hf_ftp_response_arg, tvb, offset,
365 offset = next_offset;
368 * Show the rest of the request or response as text,
370 * XXX - only if there's a continuation indicator?
372 while (tvb_offset_exists(tvb, offset)) {
374 * Find the end of the line.
376 linelen = tvb_find_line_end(tvb, offset, -1,
377 &next_offset, FALSE);
382 proto_tree_add_text(ftp_tree, tvb, offset,
383 next_offset - offset, "%s",
384 tvb_format_text(tvb, offset, next_offset - offset));
385 offset = next_offset;
391 dissect_ftpdata(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
393 proto_tree *ti, *ftp_data_tree;
396 if (check_col(pinfo->cinfo, COL_PROTOCOL))
397 col_set_str(pinfo->cinfo, COL_PROTOCOL, "FTP-DATA");
399 if (check_col(pinfo->cinfo, COL_INFO)) {
400 col_add_fstr(pinfo->cinfo, COL_INFO, "FTP Data: %u bytes",
401 tvb_reported_length(tvb));
405 data_length = tvb_length(tvb);
407 ti = proto_tree_add_item(tree, proto_ftp_data, tvb, 0, -1,
409 ftp_data_tree = proto_item_add_subtree(ti, ett_ftp_data);
412 * XXX - if this is binary data, it'll produce
413 * a *really* long line.
415 proto_tree_add_text(ftp_data_tree, tvb, 0, data_length,
416 "FTP Data: %s", tvb_format_text(tvb, 0, data_length));
421 proto_register_ftp(void)
423 static hf_register_info hf[] = {
425 { "Response", "ftp.response",
426 FT_BOOLEAN, BASE_NONE, NULL, 0x0,
427 "TRUE if FTP response", HFILL }},
430 { "Request", "ftp.request",
431 FT_BOOLEAN, BASE_NONE, NULL, 0x0,
432 "TRUE if FTP request", HFILL }},
434 { &hf_ftp_request_command,
435 { "Request command", "ftp.request.command",
436 FT_STRING, BASE_NONE, NULL, 0x0,
439 { &hf_ftp_request_arg,
440 { "Request arg", "ftp.request.arg",
441 FT_STRING, BASE_NONE, NULL, 0x0,
444 { &hf_ftp_response_code,
445 { "Response code", "ftp.response.code",
446 FT_UINT32, BASE_DEC, NULL, 0x0,
449 { &hf_ftp_response_arg,
450 { "Response arg", "ftp.response.arg",
451 FT_STRING, BASE_NONE, NULL, 0x0,
454 static gint *ett[] = {
459 proto_ftp = proto_register_protocol("File Transfer Protocol (FTP)", "FTP",
461 proto_ftp_data = proto_register_protocol("FTP Data", "FTP-DATA", "ftp-data");
462 proto_register_field_array(proto_ftp, hf, array_length(hf));
463 proto_register_subtree_array(ett, array_length(ett));
465 ftpdata_handle = create_dissector_handle(dissect_ftpdata, proto_ftp_data);
469 proto_reg_handoff_ftp(void)
471 dissector_handle_t ftpdata_handle, ftp_handle;
473 ftpdata_handle = create_dissector_handle(dissect_ftpdata, proto_ftp_data);
474 dissector_add("tcp.port", TCP_PORT_FTPDATA, ftpdata_handle);
475 ftp_handle = create_dissector_handle(dissect_ftp, proto_ftp);
476 dissector_add("tcp.port", TCP_PORT_FTP, ftp_handle);