2 * Routines for tftp packet dissection
4 * Richard Sharpe <rsharpe@ns.aus.com>
5 * Craig Newell <CraigN@cheque.uq.edu.au>
6 * RFC2347 TFTP Option Extension
8 * $Id: packet-tftp.c,v 1.27 2001/09/03 10:33:07 guy Exp $
10 * Ethereal - Network traffic analyzer
11 * By Gerald Combs <gerald@ethereal.com>
12 * Copyright 1998 Gerald Combs
14 * Copied from packet-bootp.c
16 * This program is free software; you can redistribute it and/or
17 * modify it under the terms of the GNU General Public License
18 * as published by the Free Software Foundation; either version 2
19 * of the License, or (at your option) any later version.
21 * This program is distributed in the hope that it will be useful,
22 * but WITHOUT ANY WARRANTY; without even the implied warranty of
23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
24 * GNU General Public License for more details.
26 * You should have received a copy of the GNU General Public License
27 * along with this program; if not, write to the Free Software
28 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
35 #ifdef HAVE_SYS_TYPES_H
36 # include <sys/types.h>
39 #ifdef HAVE_NETINET_IN_H
40 # include <netinet/in.h>
45 #include "conversation.h"
47 static int proto_tftp = -1;
48 static int hf_tftp_opcode = -1;
49 static int hf_tftp_source_file = -1;
50 static int hf_tftp_destination_file = -1;
51 static int hf_tftp_transfer_type = -1;
52 static int hf_tftp_blocknum = -1;
53 static int hf_tftp_error_code = -1;
54 static int hf_tftp_error_string = -1;
56 static gint ett_tftp = -1;
58 #define UDP_PORT_TFTP 69
67 static const value_string tftp_opcode_vals[] = {
68 { TFTP_RRQ, "Read Request" },
69 { TFTP_WRQ, "Write Request" },
70 { TFTP_DATA, "Data Packet" },
71 { TFTP_ACK, "Acknowledgement" },
72 { TFTP_ERROR, "Error Code" },
73 { TFTP_OACK, "Option Acknowledgement" },
77 static const value_string tftp_error_code_vals[] = {
79 { 1, "File not found" },
80 { 2, "Access violation" },
81 { 3, "Disk full or allocation exceeded" },
82 { 4, "Illegal TFTP Operation" },
83 { 5, "Unknown transfer ID" },
84 { 6, "File already exists" },
85 { 7, "No such user" },
89 static void tftp_dissect_options(tvbuff_t *tvb, int offset, proto_tree *tree);
92 dissect_tftp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
94 proto_tree *tftp_tree;
96 conversation_t *conversation;
101 CHECK_DISPLAY_AS_DATA(proto_tftp, tvb, pinfo, tree);
103 pinfo->current_proto = "TFTP";
106 * The first TFTP packet goes to the TFTP port; the second one
107 * comes from some *other* port, but goes back to the same
108 * IP address and port as the ones from which the first packet
109 * came; all subsequent packets go between those two IP addresses
112 * If this packet went to the TFTP port, we check to see if
113 * there's already a conversation with one address/port pair
114 * matching the source IP address and port of this packet,
115 * the other address matching the destination IP address of this
116 * packet, and any destination port.
118 * If not, we create one, with its address 1/port 1 pair being
119 * the source address/port of this packet, its address 2 being
120 * the destination address of this packet, and its port 2 being
121 * wildcarded, and give it the TFTP dissector as a dissector.
123 if (pinfo->destport == UDP_PORT_TFTP) {
124 conversation = find_conversation(&pinfo->src, &pinfo->dst, PT_UDP,
125 pinfo->srcport, 0, NO_PORT_B);
126 if (conversation == NULL) {
127 conversation = conversation_new(&pinfo->src, &pinfo->dst, PT_UDP,
128 pinfo->srcport, 0, NO_PORT2);
129 conversation_set_dissector(conversation, dissect_tftp);
133 if (check_col(pinfo->fd, COL_PROTOCOL))
134 col_set_str(pinfo->fd, COL_PROTOCOL, "TFTP");
136 opcode = tvb_get_ntohs(tvb, offset);
138 if (check_col(pinfo->fd, COL_INFO)) {
140 col_add_fstr(pinfo->fd, COL_INFO, "TFTP %s",
141 val_to_str(opcode, tftp_opcode_vals, "Unknown (0x%04x)"));
147 ti = proto_tree_add_item(tree, proto_tftp, tvb, offset,
148 tvb_length_remaining(tvb, offset), FALSE);
149 tftp_tree = proto_item_add_subtree(ti, ett_tftp);
151 proto_tree_add_uint(tftp_tree, hf_tftp_opcode, tvb,
157 i1 = tvb_strsize(tvb, offset);
158 proto_tree_add_item(tftp_tree, hf_tftp_source_file,
159 tvb, offset, i1, FALSE);
162 i1 = tvb_strsize(tvb, offset);
163 ti = proto_tree_add_item(tftp_tree, hf_tftp_transfer_type,
164 tvb, offset, i1, FALSE);
167 tftp_dissect_options(tvb, offset, tftp_tree);
170 i1 = tvb_strsize(tvb, offset);
171 proto_tree_add_item(tftp_tree, hf_tftp_destination_file,
172 tvb, offset, i1, FALSE);
175 i1 = tvb_strsize(tvb, offset);
176 ti = proto_tree_add_item(tftp_tree, hf_tftp_transfer_type,
177 tvb, offset, i1, FALSE);
180 tftp_dissect_options(tvb, offset, tftp_tree);
183 proto_tree_add_item(tftp_tree, hf_tftp_blocknum, tvb, offset, 2,
187 proto_tree_add_text(tftp_tree, tvb, offset, tvb_length_remaining(tvb, offset),
188 "Data (%d bytes)", tvb_length_remaining(tvb, offset));
191 proto_tree_add_item(tftp_tree, hf_tftp_blocknum, tvb, offset, 2,
195 proto_tree_add_item(tftp_tree, hf_tftp_error_code, tvb, offset, 2,
199 i1 = tvb_strsize(tvb, offset);
200 proto_tree_add_item(tftp_tree, hf_tftp_error_string, tvb, offset,
204 tftp_dissect_options(tvb, offset, tftp_tree);
207 proto_tree_add_text(tftp_tree, tvb, offset, tvb_length_remaining(tvb, offset),
208 "Data (%d bytes)", tvb_length_remaining(tvb, offset));
216 tftp_dissect_options(tvbuff_t *tvb, int offset, proto_tree *tree)
218 int option_len, value_len;
221 while (tvb_offset_exists(tvb, offset)) {
222 option_len = tvb_strsize(tvb, offset); /* length of option */
223 value_offset = offset + option_len;
224 value_len = tvb_strsize(tvb, value_offset); /* length of value */
225 proto_tree_add_text(tree, tvb, offset, option_len+value_len,
227 tvb_get_ptr(tvb, offset, option_len),
228 tvb_get_ptr(tvb, value_offset, value_len));
229 offset += option_len + value_len;
234 proto_register_tftp(void)
236 static hf_register_info hf[] = {
238 { "Opcode", "tftp.opcode",
239 FT_UINT16, BASE_DEC, VALS(tftp_opcode_vals), 0x0,
240 "TFTP message type", HFILL }},
242 { &hf_tftp_source_file,
243 { "Source File", "tftp.source_file",
244 FT_STRINGZ, BASE_DEC, NULL, 0x0,
245 "TFTP source file name", HFILL }},
247 { &hf_tftp_destination_file,
248 { "DESTINATION File", "tftp.destination_file",
249 FT_STRINGZ, BASE_DEC, NULL, 0x0,
250 "TFTP source file name", HFILL }},
252 { &hf_tftp_transfer_type,
253 { "Type", "tftp.type",
254 FT_STRINGZ, BASE_DEC, NULL, 0x0,
255 "TFTP transfer type", HFILL }},
258 { "Block", "tftp.block",
259 FT_UINT16, BASE_DEC, NULL, 0x0,
260 "Block number", HFILL }},
262 { &hf_tftp_error_code,
263 { "Error code", "tftp.error.code",
264 FT_UINT16, BASE_DEC, VALS(tftp_error_code_vals), 0x0,
265 "Error code in case of TFTP error message", HFILL }},
267 { &hf_tftp_error_string,
268 { "Error message", "tftp.error.message",
269 FT_STRINGZ, BASE_DEC, NULL, 0x0,
270 "Error string in case of TFTP error message", HFILL }}
272 static gint *ett[] = {
276 proto_tftp = proto_register_protocol("Trivial File Transfer Protocol",
278 proto_register_field_array(proto_tftp, hf, array_length(hf));
279 proto_register_subtree_array(ett, array_length(ett));
283 proto_reg_handoff_tftp(void)
285 dissector_add("udp.port", UDP_PORT_TFTP, dissect_tftp, proto_tftp);