2 * Routines for UDP packet disassembly
4 * $Id: packet-udp.c,v 1.64 2000/04/14 06:42:50 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>
49 #include "packet-ncp.h"
50 #include "packet-rip.h"
51 #include "packet-rpc.h"
52 #include "packet-rx.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;
84 decode_udp_ports( const u_char *pd, int offset, frame_data *fd,
85 proto_tree *tree, int uh_sport, int uh_dport){
87 /* Determine if there is a sub-dissector and call it. This has been */
88 /* separated into a stand alone routine to other protocol dissectors */
89 /* can call to it, ie. socks */
91 dissector_t sub_dissector;
94 /* determine if this packet is part of a conversation and call dissector */
95 /* for the conversation if available */
97 sub_dissector = find_conversation_dissector( &pi.src, &pi.dst, PT_UDP,
100 (sub_dissector)(pd, offset, fd, tree);
104 /* ONC RPC. We can't base this on anything in the UDP header; we have
105 to look at the payload. If "dissect_rpc()" returns TRUE, it was
106 an RPC packet, otherwise it's some other type of packet. */
107 if (dissect_rpc(pd, offset, fd, tree))
110 /* try to apply the plugins */
113 plugin *pt_plug = plugin_list;
115 if (enabled_plugins_number > 0) {
117 if (pt_plug->enabled && !strcmp(pt_plug->protocol, "udp") &&
118 tree && dfilter_apply(pt_plug->filter, tree, pd, fd->cap_len)) {
119 pt_plug->dissector(pd, offset, fd, tree);
122 pt_plug = pt_plug->next;
128 /* XXX - we should do all of this through the table of ports. */
129 #define PORT_IS(port) (uh_sport == port || uh_dport == port)
130 if (PORT_IS(UDP_PORT_NCP))
131 dissect_ncp(pd, offset, fd, tree); /* XXX -- need to handle nw_server_address */
132 else if (PORT_IS(UDP_PORT_VINES)) {
133 /* FIXME: AFAIK, src and dst port must be the same */
134 dissect_vines_frp(pd, offset, fd, tree);
135 } else if (PORT_IS(UDP_PORT_TFTP)) {
136 /* This is the first point of call, but it adds a dynamic call */
137 dissector_add("udp.port", MAX(uh_sport, uh_dport), dissect_tftp); /* Add to table */
138 dissect_tftp(pd, offset, fd, tree);
140 /* OK, find a routine in the table, else use the default */
142 if (!dissector_try_port(udp_dissector_table, uh_sport, pd, offset,
144 !dissector_try_port(udp_dissector_table, uh_dport, pd, offset,
146 dissect_data(pd, offset, fd, tree);
152 dissect_udp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
154 guint16 uh_sport, uh_dport, uh_ulen, uh_sum;
155 proto_tree *udp_tree;
158 if (!BYTES_ARE_IN_FRAME(offset, sizeof(e_udphdr))) {
159 dissect_data(pd, offset, fd, tree);
163 /* Avoids alignment problems on many architectures. */
164 memcpy(&uh, &pd[offset], sizeof(e_udphdr));
165 uh_sport = ntohs(uh.uh_sport);
166 uh_dport = ntohs(uh.uh_dport);
167 uh_ulen = ntohs(uh.uh_ulen);
168 uh_sum = ntohs(uh.uh_sum);
170 if (check_col(fd, COL_PROTOCOL))
171 col_add_str(fd, COL_PROTOCOL, "UDP");
172 if (check_col(fd, COL_INFO))
173 col_add_fstr(fd, COL_INFO, "Source port: %s Destination port: %s",
174 get_udp_port(uh_sport), get_udp_port(uh_dport));
177 ti = proto_tree_add_item(tree, proto_udp, offset, 8);
178 udp_tree = proto_item_add_subtree(ti, ett_udp);
180 proto_tree_add_uint_format(udp_tree, hf_udp_srcport, offset, 2, uh_sport,
181 "Source port: %s (%u)", get_udp_port(uh_sport), uh_sport);
182 proto_tree_add_uint_format(udp_tree, hf_udp_dstport, offset + 2, 2, uh_dport,
183 "Destination port: %s (%u)", get_udp_port(uh_dport), uh_dport);
185 proto_tree_add_item_hidden(udp_tree, hf_udp_port, offset, 2, uh_sport);
186 proto_tree_add_item_hidden(udp_tree, hf_udp_port, offset+2, 2, uh_dport);
188 proto_tree_add_item(udp_tree, hf_udp_length, offset + 4, 2, uh_ulen);
189 proto_tree_add_uint_format(udp_tree, hf_udp_checksum, offset + 6, 2, uh_sum,
190 "Checksum: 0x%04x", uh_sum);
193 /* Skip over header */
197 pi.srcport = uh_sport;
198 pi.destport = uh_dport;
200 /* call sub-dissectors */
201 decode_udp_ports( pd, offset, fd, tree, uh_sport, uh_dport);
206 proto_register_udp(void)
208 static hf_register_info hf[] = {
210 { "Source Port", "udp.srcport", FT_UINT16, BASE_DEC, NULL, 0x0,
214 { "Destination Port", "udp.dstport", FT_UINT16, BASE_DEC, NULL, 0x0,
218 { "Source or Destination Port", "udp.port", FT_UINT16, BASE_DEC, NULL, 0x0,
222 { "Length", "udp.length", FT_UINT16, BASE_DEC, NULL, 0x0,
226 { "Checksum", "udp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
229 static gint *ett[] = {
233 proto_udp = proto_register_protocol("User Datagram Protocol", "udp");
234 proto_register_field_array(proto_udp, hf, array_length(hf));
235 proto_register_subtree_array(ett, array_length(ett));
237 /* subdissector code */
238 udp_dissector_table = register_dissector_table("udp.port");