2 * Routines for UDP packet disassembly
4 * $Id: packet-udp.c,v 1.25 1999/10/02 16:58:41 deniel 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 int hf_udp_srcport = -1;
49 int hf_udp_dstport = -1;
51 int hf_udp_length = -1;
52 int hf_udp_checksum = -1;
54 /* UDP structs and definitions */
56 typedef struct _e_udphdr {
63 /* UDP Ports -> should go in packet-udp.h */
65 #define UDP_PORT_DNS 53
66 #define UDP_PORT_BOOTPS 67
67 #define UDP_PORT_TFTP 69
68 #define UDP_PORT_IPX 213
69 #define UDP_PORT_NBNS 137
70 #define UDP_PORT_NBDGM 138
71 #define UDP_PORT_SNMP 161
72 #define UDP_PORT_ISAKMP 500
73 #define UDP_PORT_RIP 520
74 #define UDP_PORT_VINES 573
75 #define UDP_PORT_RADIUS 1645
76 #define UDP_PORT_RADIUS_NEW 1812
77 #define UDP_PORT_RADACCT 1646
78 #define UDP_PORT_RADACCT_NEW 1813
79 #define UDP_PORT_ICP 3130
83 void (*dissect)(const u_char *, int, frame_data *, proto_tree *);
84 struct hash_struct *next;
87 static struct hash_struct *hash_table[256];
90 * These routines are for UDP, will be generalized soon: RJS
92 * XXX - note that they should probably check the IP address as well as
93 * the port number, so that we don't mistakenly identify packets as, say,
94 * TFTP, merely because they have a source or destination port number
95 * equal to the port being used by a TFTP daemon on some machine other
96 * than the one they're going to or from.
99 struct hash_struct *udp_find_hash_ent(guint16 proto) {
101 int idx = proto % 256;
102 struct hash_struct *hash_ent = hash_table[idx];
104 while (hash_ent != NULL) {
106 if (hash_ent -> proto == proto)
109 hash_ent = hash_ent -> next;
117 void udp_hash_add(guint16 proto,
118 void (*dissect)(const u_char *, int, frame_data *, proto_tree *)) {
120 int idx = proto % 256; /* Simply take the remainder, hope for no collisions */
121 struct hash_struct *hash_ent = (struct hash_struct *)malloc(sizeof(struct hash_struct));
122 struct hash_struct *hash_ent2;
124 hash_ent -> proto = proto;
125 hash_ent -> dissect = dissect;
126 hash_ent -> next = NULL;
128 if (hash_ent == NULL) {
130 fprintf(stderr, "Could not allocate space for hash structure in dissect_udp\n");
134 if (hash_table[idx]) { /* Something, add on end */
136 hash_ent2 = hash_table[idx];
138 while (hash_ent2 -> next != NULL)
139 hash_ent2 = hash_ent2 -> next;
141 hash_ent2 -> next = hash_ent; /* Bad in pathalogical cases */
146 hash_table[idx] = hash_ent;
152 void init_dissect_udp(void) {
156 for (i = 0; i < 256; i++) {
158 hash_table[i] = NULL;
162 /* Now add the protocols we know about */
164 udp_hash_add(UDP_PORT_BOOTPS, dissect_bootp);
165 udp_hash_add(UDP_PORT_TFTP, dissect_tftp);
170 dissect_udp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
172 guint16 uh_sport, uh_dport, uh_ulen, uh_sum;
173 struct hash_struct *dissect_routine = NULL;
174 proto_tree *udp_tree;
177 if (!BYTES_ARE_IN_FRAME(offset, sizeof(e_udphdr))) {
178 dissect_data(pd, offset, fd, tree);
182 /* Avoids alignment problems on many architectures. */
183 memcpy(&uh, &pd[offset], sizeof(e_udphdr));
184 uh_sport = ntohs(uh.uh_sport);
185 uh_dport = ntohs(uh.uh_dport);
186 uh_ulen = ntohs(uh.uh_ulen);
187 uh_sum = ntohs(uh.uh_sum);
189 if (check_col(fd, COL_PROTOCOL))
190 col_add_str(fd, COL_PROTOCOL, "UDP");
191 if (check_col(fd, COL_INFO))
192 col_add_fstr(fd, COL_INFO, "Source port: %s Destination port: %s",
193 get_udp_port(uh_sport), get_udp_port(uh_dport));
194 if (check_col(fd, COL_RES_SRC_PORT))
195 col_add_str(fd, COL_RES_SRC_PORT, get_udp_port(uh_sport));
196 if (check_col(fd, COL_UNRES_SRC_PORT))
197 col_add_fstr(fd, COL_UNRES_SRC_PORT, "%u", uh_sport);
198 if (check_col(fd, COL_RES_DST_PORT))
199 col_add_str(fd, COL_RES_DST_PORT, get_udp_port(uh_dport));
200 if (check_col(fd, COL_UNRES_DST_PORT))
201 col_add_fstr(fd, COL_UNRES_DST_PORT, "%u", uh_dport);
204 ti = proto_tree_add_item(tree, proto_udp, offset, 8);
205 udp_tree = proto_item_add_subtree(ti, ETT_UDP);
207 proto_tree_add_item_format(udp_tree, hf_udp_srcport, offset, 2, uh_sport,
208 "Source port: %s (%u)", get_udp_port(uh_sport), uh_sport);
209 proto_tree_add_item_format(udp_tree, hf_udp_dstport, offset + 2, 2, uh_dport,
210 "Destination port: %s (%u)", get_udp_port(uh_dport), uh_dport);
212 proto_tree_add_item_hidden(udp_tree, hf_udp_port, offset, 2, uh_sport);
213 proto_tree_add_item_hidden(udp_tree, hf_udp_port, offset+2, 2, uh_dport);
215 proto_tree_add_item(udp_tree, hf_udp_length, offset + 4, 2, uh_ulen);
216 proto_tree_add_item_format(udp_tree, hf_udp_checksum, offset + 6, 2, uh_sum,
217 "Checksum: 0x%04x", uh_sum);
220 /* Skip over header */
223 /* XXX - we should do all of this through the table of ports. */
224 #define PORT_IS(port) (uh_sport == port || uh_dport == port)
225 if (PORT_IS(UDP_PORT_BOOTPS))
226 dissect_bootp(pd, offset, fd, tree);
227 else if (PORT_IS(UDP_PORT_DNS))
228 dissect_dns(pd, offset, fd, tree);
229 else if (PORT_IS(UDP_PORT_ISAKMP))
230 dissect_isakmp(pd, offset, fd, tree);
231 else if (PORT_IS(UDP_PORT_RIP)) {
232 /* we should check the source port too (RIP: UDP src and dst port 520) */
233 dissect_rip(pd, offset, fd, tree);
234 } else if (PORT_IS(UDP_PORT_NBNS))
235 dissect_nbns(pd, offset, fd, tree);
236 else if (PORT_IS(UDP_PORT_NBDGM))
237 dissect_nbdgm(pd, offset, fd, tree);
238 else if (PORT_IS(UDP_PORT_IPX)) /* RFC 1234 */
239 dissect_ipx(pd, offset, fd, tree);
240 #if defined(HAVE_UCD_SNMP_SNMP_H) || defined(HAVE_SNMP_SNMP_H)
241 else if (PORT_IS(UDP_PORT_SNMP))
242 dissect_snmp(pd, offset, fd, tree);
244 else if (PORT_IS(UDP_PORT_VINES)) {
245 /* FIXME: AFAIK, src and dst port must be the same */
246 dissect_vines_frp(pd, offset, fd, tree);
247 } else if (PORT_IS(UDP_PORT_TFTP)) {
248 /* This is the first point of call, but it adds a dynamic call */
249 udp_hash_add(MAX(uh_sport, uh_dport), dissect_tftp); /* Add to table */
250 dissect_tftp(pd, offset, fd, tree);
251 } else if (PORT_IS(UDP_PORT_RADIUS) ||
252 PORT_IS(UDP_PORT_RADACCT) ||
253 PORT_IS(UDP_PORT_RADIUS_NEW) ||
254 PORT_IS(UDP_PORT_RADACCT_NEW) ) {
255 dissect_radius(pd, offset, fd, tree);
256 } else if ( PORT_IS(UDP_PORT_ICP)) {
257 dissect_icp(pd,offset,fd,tree);
259 /* OK, find a routine in the table, else use the default */
261 if ((dissect_routine = udp_find_hash_ent(uh_sport))) {
263 struct hash_struct *dr2 = udp_find_hash_ent(uh_dport);
265 if (dr2 == NULL) { /* Not in the table, add */
267 udp_hash_add(uh_dport, dissect_tftp);
271 dissect_routine -> dissect(pd, offset, fd, tree);
273 else if ((dissect_routine = udp_find_hash_ent(uh_dport))) {
275 dissect_routine -> dissect(pd, offset, fd, tree);
280 dissect_data(pd, offset, fd, tree);
286 proto_register_udp(void)
288 static hf_register_info hf[] = {
290 { "Source Port", "udp.srcport", FT_UINT16, NULL }},
293 { "Destination Port", "udp.dstport", FT_UINT16, NULL }},
296 { "Source or Destination Port", "udp.port", FT_UINT16, NULL }},
299 { "Length", "udp.length", FT_UINT16, NULL }},
302 { "Checksum", "udp.checksum", FT_UINT16, NULL }}
305 proto_udp = proto_register_protocol("User Datagram Protocol", "udp");
306 proto_register_field_array(proto_udp, hf, array_length(hf));