2 * Routines for UDP packet disassembly
4 * $Id: packet-udp.c,v 1.66 2000/04/17 02:39:55 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_NCP 524
78 #define UDP_PORT_VINES 573
80 static dissector_table_t udp_dissector_table;
82 /* Determine if there is a sub-dissector and call it. This has been */
83 /* separated into a stand alone routine to other protocol dissectors */
84 /* can call to it, ie. socks */
87 decode_udp_ports( const u_char *pd, int offset, frame_data *fd,
88 proto_tree *tree, int uh_sport, int uh_dport){
89 dissector_t sub_dissector;
91 /* determine if this packet is part of a conversation and call dissector */
92 /* for the conversation if available */
94 sub_dissector = find_conversation_dissector( &pi.src, &pi.dst, PT_UDP,
97 (sub_dissector)(pd, offset, fd, tree);
101 /* ONC RPC. We can't base this on anything in the UDP header; we have
102 to look at the payload. If "dissect_rpc()" returns TRUE, it was
103 an RPC packet, otherwise it's some other type of packet. */
104 if (dissect_rpc(pd, offset, fd, tree))
107 /* try to apply the plugins */
110 plugin *pt_plug = plugin_list;
112 if (enabled_plugins_number > 0) {
114 if (pt_plug->enabled && !strcmp(pt_plug->protocol, "udp") &&
115 tree && dfilter_apply(pt_plug->filter, tree, pd, fd->cap_len)) {
116 pt_plug->dissector(pd, offset, fd, tree);
119 pt_plug = pt_plug->next;
125 /* do lookup with the subdissector table */
126 if (dissector_try_port(udp_dissector_table, uh_sport, pd, offset, fd, tree) ||
127 dissector_try_port(udp_dissector_table, uh_dport, pd, offset, fd, tree))
130 /* XXX - we should do all of this through the table of ports. */
131 #define PORT_IS(port) (uh_sport == port || uh_dport == port)
132 if (PORT_IS(UDP_PORT_NCP))
133 dissect_ncp(pd, offset, fd, tree); /* XXX -- need to handle nw_server_address */
134 else if (PORT_IS(UDP_PORT_VINES)) {
135 /* FIXME: AFAIK, src and dst port must be the same */
136 dissect_vines_frp(pd, offset, fd, tree);
137 } else if (PORT_IS(UDP_PORT_TFTP)) {
138 /* This is the first point of call, but it adds a dynamic call */
139 dissector_add("udp.port", MAX(uh_sport, uh_dport), dissect_tftp); /* Add to table */
140 dissect_tftp(pd, offset, fd, tree);
142 dissect_data(pd, offset, fd, tree);
147 dissect_udp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
149 guint16 uh_sport, uh_dport, uh_ulen, uh_sum;
150 proto_tree *udp_tree;
153 if (!BYTES_ARE_IN_FRAME(offset, sizeof(e_udphdr))) {
154 dissect_data(pd, offset, fd, tree);
158 /* Avoids alignment problems on many architectures. */
159 memcpy(&uh, &pd[offset], sizeof(e_udphdr));
160 uh_sport = ntohs(uh.uh_sport);
161 uh_dport = ntohs(uh.uh_dport);
162 uh_ulen = ntohs(uh.uh_ulen);
163 uh_sum = ntohs(uh.uh_sum);
165 if (check_col(fd, COL_PROTOCOL))
166 col_add_str(fd, COL_PROTOCOL, "UDP");
167 if (check_col(fd, COL_INFO))
168 col_add_fstr(fd, COL_INFO, "Source port: %s Destination port: %s",
169 get_udp_port(uh_sport), get_udp_port(uh_dport));
172 ti = proto_tree_add_item(tree, proto_udp, offset, 8);
173 udp_tree = proto_item_add_subtree(ti, ett_udp);
175 proto_tree_add_uint_format(udp_tree, hf_udp_srcport, offset, 2, uh_sport,
176 "Source port: %s (%u)", get_udp_port(uh_sport), uh_sport);
177 proto_tree_add_uint_format(udp_tree, hf_udp_dstport, offset + 2, 2, uh_dport,
178 "Destination port: %s (%u)", get_udp_port(uh_dport), uh_dport);
180 proto_tree_add_item_hidden(udp_tree, hf_udp_port, offset, 2, uh_sport);
181 proto_tree_add_item_hidden(udp_tree, hf_udp_port, offset+2, 2, uh_dport);
183 proto_tree_add_item(udp_tree, hf_udp_length, offset + 4, 2, uh_ulen);
184 proto_tree_add_uint_format(udp_tree, hf_udp_checksum, offset + 6, 2, uh_sum,
185 "Checksum: 0x%04x", uh_sum);
188 /* Skip over header */
192 pi.srcport = uh_sport;
193 pi.destport = uh_dport;
195 /* call sub-dissectors */
196 decode_udp_ports( pd, offset, fd, tree, uh_sport, uh_dport);
201 proto_register_udp(void)
203 static hf_register_info hf[] = {
205 { "Source Port", "udp.srcport", FT_UINT16, BASE_DEC, NULL, 0x0,
209 { "Destination Port", "udp.dstport", FT_UINT16, BASE_DEC, NULL, 0x0,
213 { "Source or Destination Port", "udp.port", FT_UINT16, BASE_DEC, NULL, 0x0,
217 { "Length", "udp.length", FT_UINT16, BASE_DEC, NULL, 0x0,
221 { "Checksum", "udp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
224 static gint *ett[] = {
228 proto_udp = proto_register_protocol("User Datagram Protocol", "udp");
229 proto_register_field_array(proto_udp, hf, array_length(hf));
230 proto_register_subtree_array(ett, array_length(ett));
232 /* subdissector code */
233 udp_dissector_table = register_dissector_table("udp.port");
237 proto_reg_handoff_udp(void)
239 dissector_add("ip.proto", IP_PROTO_UDP, dissect_udp);