2 * Routines for UDP packet disassembly
4 * $Id: packet-udp.c,v 1.69 2000/04/20 07:05:57 guy Exp $
6 * Ethereal - Network traffic analyzer
7 * By Gerald Combs <gerald@zing.org>
8 * Copyright 1998 Gerald Combs
10 * Richard Sharpe, 13-Feb-1999, added dispatch table support and
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version 2
16 * of the License, or (at your option) any later version.
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
23 * You should have received a copy of the GNU General Public License
24 * along with this program; if not, write to the Free Software
25 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
32 #ifdef HAVE_SYS_TYPES_H
33 # include <sys/types.h>
36 #ifdef HAVE_NETINET_IN_H
37 # include <netinet/in.h>
48 #include "packet-udp.h"
50 #include "packet-ip.h"
51 #include "packet-ncp.h"
52 #include "packet-rpc.h"
53 #include "packet-tftp.h"
54 #include "packet-vines.h"
56 static int proto_udp = -1;
57 static int hf_udp_srcport = -1;
58 static int hf_udp_dstport = -1;
59 static int hf_udp_port = -1;
60 static int hf_udp_length = -1;
61 static int hf_udp_checksum = -1;
63 static gint ett_udp = -1;
65 /* UDP structs and definitions */
67 typedef struct _e_udphdr {
74 /* UDP Ports -> should go in packet-udp.h */
76 #define UDP_PORT_TFTP 69
77 #define UDP_PORT_VINES 573
79 static dissector_table_t udp_dissector_table;
81 /* Determine if there is a sub-dissector and call it. This has been */
82 /* separated into a stand alone routine to other protocol dissectors */
83 /* can call to it, ie. socks */
86 decode_udp_ports( const u_char *pd, int offset, frame_data *fd,
87 proto_tree *tree, int uh_sport, int uh_dport){
88 dissector_t sub_dissector;
90 /* determine if this packet is part of a conversation and call dissector */
91 /* for the conversation if available */
93 sub_dissector = find_conversation_dissector( &pi.src, &pi.dst, PT_UDP,
96 (sub_dissector)(pd, offset, fd, tree);
100 /* ONC RPC. We can't base this on anything in the UDP header; we have
101 to look at the payload. If "dissect_rpc()" returns TRUE, it was
102 an RPC packet, otherwise it's some other type of packet. */
103 if (dissect_rpc(pd, offset, fd, tree))
106 /* try to apply the plugins */
109 plugin *pt_plug = plugin_list;
111 if (enabled_plugins_number > 0) {
113 if (pt_plug->enabled && !strcmp(pt_plug->protocol, "udp") &&
114 tree && dfilter_apply(pt_plug->filter, tree, pd, fd->cap_len)) {
115 pt_plug->dissector(pd, offset, fd, tree);
118 pt_plug = pt_plug->next;
124 /* do lookup with the subdissector table */
125 if (dissector_try_port(udp_dissector_table, uh_sport, pd, offset, fd, tree) ||
126 dissector_try_port(udp_dissector_table, uh_dport, pd, offset, fd, tree))
129 /* XXX - we should do these with the subdissector table as well. */
130 #define PORT_IS(port) (uh_sport == port || uh_dport == port)
131 if (PORT_IS(UDP_PORT_VINES)) {
132 /* FIXME: AFAIK, src and dst port must be the same */
133 dissect_vines_frp(pd, offset, fd, tree);
134 } else if (PORT_IS(UDP_PORT_TFTP)) {
135 /* This is the first point of call, but it adds a dynamic call */
136 dissector_add("udp.port", MAX(uh_sport, uh_dport), dissect_tftp); /* Add to table */
137 dissect_tftp(pd, offset, fd, tree);
139 dissect_data(pd, offset, fd, tree);
144 dissect_udp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
146 guint16 uh_sport, uh_dport, uh_ulen, uh_sum;
147 proto_tree *udp_tree;
150 if (!BYTES_ARE_IN_FRAME(offset, sizeof(e_udphdr))) {
151 dissect_data(pd, offset, fd, tree);
155 /* Avoids alignment problems on many architectures. */
156 memcpy(&uh, &pd[offset], sizeof(e_udphdr));
157 uh_sport = ntohs(uh.uh_sport);
158 uh_dport = ntohs(uh.uh_dport);
159 uh_ulen = ntohs(uh.uh_ulen);
160 uh_sum = ntohs(uh.uh_sum);
162 if (check_col(fd, COL_PROTOCOL))
163 col_add_str(fd, COL_PROTOCOL, "UDP");
164 if (check_col(fd, COL_INFO))
165 col_add_fstr(fd, COL_INFO, "Source port: %s Destination port: %s",
166 get_udp_port(uh_sport), get_udp_port(uh_dport));
169 ti = proto_tree_add_item(tree, proto_udp, offset, 8);
170 udp_tree = proto_item_add_subtree(ti, ett_udp);
172 proto_tree_add_uint_format(udp_tree, hf_udp_srcport, offset, 2, uh_sport,
173 "Source port: %s (%u)", get_udp_port(uh_sport), uh_sport);
174 proto_tree_add_uint_format(udp_tree, hf_udp_dstport, offset + 2, 2, uh_dport,
175 "Destination port: %s (%u)", get_udp_port(uh_dport), uh_dport);
177 proto_tree_add_item_hidden(udp_tree, hf_udp_port, offset, 2, uh_sport);
178 proto_tree_add_item_hidden(udp_tree, hf_udp_port, offset+2, 2, uh_dport);
180 proto_tree_add_item(udp_tree, hf_udp_length, offset + 4, 2, uh_ulen);
181 proto_tree_add_uint_format(udp_tree, hf_udp_checksum, offset + 6, 2, uh_sum,
182 "Checksum: 0x%04x", uh_sum);
185 /* Skip over header */
189 pi.srcport = uh_sport;
190 pi.destport = uh_dport;
192 /* call sub-dissectors */
193 decode_udp_ports( pd, offset, fd, tree, uh_sport, uh_dport);
198 proto_register_udp(void)
200 static hf_register_info hf[] = {
202 { "Source Port", "udp.srcport", FT_UINT16, BASE_DEC, NULL, 0x0,
206 { "Destination Port", "udp.dstport", FT_UINT16, BASE_DEC, NULL, 0x0,
210 { "Source or Destination Port", "udp.port", FT_UINT16, BASE_DEC, NULL, 0x0,
214 { "Length", "udp.length", FT_UINT16, BASE_DEC, NULL, 0x0,
218 { "Checksum", "udp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
221 static gint *ett[] = {
225 proto_udp = proto_register_protocol("User Datagram Protocol", "udp");
226 proto_register_field_array(proto_udp, hf, array_length(hf));
227 proto_register_subtree_array(ett, array_length(ett));
229 /* subdissector code */
230 udp_dissector_table = register_dissector_table("udp.port");
234 proto_reg_handoff_udp(void)
236 dissector_add("ip.proto", IP_PROTO_UDP, dissect_udp);