2 * Routines for UDP packet disassembly
4 * $Id: packet-udp.c,v 1.47 2000/02/01 04:13:47 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 static int proto_udp = -1;
50 static int hf_udp_srcport = -1;
51 static int hf_udp_dstport = -1;
52 static int hf_udp_port = -1;
53 static int hf_udp_length = -1;
54 static int hf_udp_checksum = -1;
56 static gint ett_udp = -1;
58 /* UDP structs and definitions */
60 typedef struct _e_udphdr {
67 /* UDP Ports -> should go in packet-udp.h */
69 #define UDP_PORT_TACACS 49
70 #define UDP_PORT_DNS 53
71 #define UDP_PORT_BOOTPS 67
72 #define UDP_PORT_TFTP 69
73 #define UDP_PORT_IPX 213
74 #define UDP_PORT_NTP 123
75 #define UDP_PORT_NBNS 137
76 #define UDP_PORT_NBDGM 138
77 #define UDP_PORT_SNMP 161
78 #define UDP_PORT_SNMP_TRAP 162
79 #define UDP_PORT_SRVLOC 427
80 #define UDP_PORT_PIM_RP_DISC 496
81 #define UDP_PORT_ISAKMP 500
82 #define UDP_PORT_WHO 513
83 #define UDP_PORT_RIP 520
84 #define UDP_PORT_RIPNG 521
85 #define UDP_PORT_NCP 524
86 #define UDP_PORT_VINES 573
87 #define UDP_PORT_RADIUS 1645
88 #define UDP_PORT_L2TP 1701
89 #define UDP_PORT_RADIUS_NEW 1812
90 #define UDP_PORT_RADACCT 1646
91 #define UDP_PORT_RADACCT_NEW 1813
92 #define UDP_PORT_HSRP 1985
93 #define UDP_PORT_ICP 3130
94 #define UDP_PORT_ICQ 4000
95 #define UDP_PORT_SAP 9875
96 #define UDP_PORT_RX_LOW 7000
97 #define UDP_PORT_RX_HIGH 7009
98 #define UDP_PORT_RX_AFS_BACKUPS 7021
99 #define UDP_PORT_WCCP 2048
103 void (*dissect)(const u_char *, int, frame_data *, proto_tree *);
104 struct hash_struct *next;
107 static struct hash_struct *hash_table[256];
110 * These routines are for UDP, will be generalized soon: RJS
112 * XXX - note that they should probably check the IP address as well as
113 * the port number, so that we don't mistakenly identify packets as, say,
114 * TFTP, merely because they have a source or destination port number
115 * equal to the port being used by a TFTP daemon on some machine other
116 * than the one they're going to or from.
119 struct hash_struct *udp_find_hash_ent(guint16 proto) {
121 int idx = proto % 256;
122 struct hash_struct *hash_ent = hash_table[idx];
124 while (hash_ent != NULL) {
126 if (hash_ent -> proto == proto)
129 hash_ent = hash_ent -> next;
137 void udp_hash_add(guint16 proto,
138 void (*dissect)(const u_char *, int, frame_data *, proto_tree *)) {
140 int idx = proto % 256; /* Simply take the remainder, hope for no collisions */
141 struct hash_struct *hash_ent = (struct hash_struct *)malloc(sizeof(struct hash_struct));
142 struct hash_struct *hash_ent2;
144 hash_ent -> proto = proto;
145 hash_ent -> dissect = dissect;
146 hash_ent -> next = NULL;
148 if (hash_ent == NULL) {
150 fprintf(stderr, "Could not allocate space for hash structure in dissect_udp\n");
154 if (hash_table[idx]) { /* Something, add on end */
156 hash_ent2 = hash_table[idx];
158 while (hash_ent2 -> next != NULL)
159 hash_ent2 = hash_ent2 -> next;
161 hash_ent2 -> next = hash_ent; /* Bad in pathalogical cases */
166 hash_table[idx] = hash_ent;
172 void init_dissect_udp(void) {
176 for (i = 0; i < 256; i++) {
178 hash_table[i] = NULL;
182 /* Now add the protocols we know about */
184 udp_hash_add(UDP_PORT_BOOTPS, dissect_bootp);
185 udp_hash_add(UDP_PORT_TFTP, dissect_tftp);
186 udp_hash_add(UDP_PORT_SAP, dissect_sap);
187 udp_hash_add(UDP_PORT_HSRP, dissect_hsrp);
188 udp_hash_add(UDP_PORT_PIM_RP_DISC, dissect_auto_rp);
189 udp_hash_add(UDP_PORT_TACACS, dissect_tacacs);
193 dissect_udp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
195 guint16 uh_sport, uh_dport, uh_ulen, uh_sum;
196 struct hash_struct *dissect_routine = NULL;
197 proto_tree *udp_tree;
200 if (!BYTES_ARE_IN_FRAME(offset, sizeof(e_udphdr))) {
201 dissect_data(pd, offset, fd, tree);
205 /* Avoids alignment problems on many architectures. */
206 memcpy(&uh, &pd[offset], sizeof(e_udphdr));
207 uh_sport = ntohs(uh.uh_sport);
208 uh_dport = ntohs(uh.uh_dport);
209 uh_ulen = ntohs(uh.uh_ulen);
210 uh_sum = ntohs(uh.uh_sum);
212 if (check_col(fd, COL_PROTOCOL))
213 col_add_str(fd, COL_PROTOCOL, "UDP");
214 if (check_col(fd, COL_INFO))
215 col_add_fstr(fd, COL_INFO, "Source port: %s Destination port: %s",
216 get_udp_port(uh_sport), get_udp_port(uh_dport));
219 ti = proto_tree_add_item(tree, proto_udp, offset, 8);
220 udp_tree = proto_item_add_subtree(ti, ett_udp);
222 proto_tree_add_item_format(udp_tree, hf_udp_srcport, offset, 2, uh_sport,
223 "Source port: %s (%u)", get_udp_port(uh_sport), uh_sport);
224 proto_tree_add_item_format(udp_tree, hf_udp_dstport, offset + 2, 2, uh_dport,
225 "Destination port: %s (%u)", get_udp_port(uh_dport), uh_dport);
227 proto_tree_add_item_hidden(udp_tree, hf_udp_port, offset, 2, uh_sport);
228 proto_tree_add_item_hidden(udp_tree, hf_udp_port, offset+2, 2, uh_dport);
230 proto_tree_add_item(udp_tree, hf_udp_length, offset + 4, 2, uh_ulen);
231 proto_tree_add_item_format(udp_tree, hf_udp_checksum, offset + 6, 2, uh_sum,
232 "Checksum: 0x%04x", uh_sum);
235 /* Skip over header */
239 pi.srcport = uh_sport;
240 pi.destport = uh_dport;
242 /* ONC RPC. We can't base this on anything in the UDP header; we have
243 to look at the payload. If "dissect_rpc()" returns TRUE, it was
244 an RPC packet, otherwise it's some other type of packet. */
245 if (dissect_rpc(pd, offset, fd, tree))
248 /* try to apply the plugins */
251 plugin *pt_plug = plugin_list;
255 if (pt_plug->enabled && !strcmp(pt_plug->protocol, "udp") &&
256 tree && dfilter_apply(pt_plug->filter, tree, pd)) {
257 pt_plug->dissector(pd, offset, fd, tree);
260 pt_plug = pt_plug->next;
266 /* XXX - we should do all of this through the table of ports. */
267 #define PORT_IS(port) (uh_sport == port || uh_dport == port)
268 if (PORT_IS(UDP_PORT_BOOTPS))
269 dissect_bootp(pd, offset, fd, tree);
270 else if (PORT_IS(UDP_PORT_DNS))
271 dissect_dns(pd, offset, fd, tree);
272 else if (PORT_IS(UDP_PORT_SRVLOC))
273 dissect_srvloc(pd, offset, fd, tree);
274 else if (PORT_IS(UDP_PORT_ISAKMP))
275 dissect_isakmp(pd, offset, fd, tree);
276 else if (PORT_IS(UDP_PORT_RIP)) {
277 /* we should check the source port too (RIP: UDP src and dst port 520) */
278 dissect_rip(pd, offset, fd, tree);
279 } else if (PORT_IS(UDP_PORT_RIPNG))
280 dissect_ripng(pd, offset, fd, tree);
281 else if (PORT_IS(UDP_PORT_NCP))
282 dissect_ncp(pd, offset, fd, tree);
283 else if (PORT_IS(UDP_PORT_NBNS))
284 dissect_nbns(pd, offset, fd, tree);
285 else if (PORT_IS(UDP_PORT_NBDGM))
286 dissect_nbdgm(pd, offset, fd, tree);
287 else if (PORT_IS(UDP_PORT_NTP))
288 dissect_ntp(pd, offset, fd, tree);
289 else if (PORT_IS(UDP_PORT_WHO))
290 dissect_who(pd, offset, fd, tree);
291 else if (PORT_IS(UDP_PORT_IPX)) /* RFC 1234 */
292 dissect_ipx(pd, offset, fd, tree);
293 else if ((uh_sport >= UDP_PORT_RX_LOW && uh_sport <= UDP_PORT_RX_HIGH) ||
294 (uh_dport >= UDP_PORT_RX_LOW && uh_dport <= UDP_PORT_RX_HIGH) ||
295 PORT_IS(UDP_PORT_RX_AFS_BACKUPS))
296 dissect_rx(pd, offset, fd, tree); /* transarc AFS's RX protocol */
297 else if (PORT_IS(UDP_PORT_SNMP) || PORT_IS(UDP_PORT_SNMP_TRAP))
298 dissect_snmp(pd, offset, fd, tree);
299 else if (PORT_IS(UDP_PORT_VINES)) {
300 /* FIXME: AFAIK, src and dst port must be the same */
301 dissect_vines_frp(pd, offset, fd, tree);
302 } else if (PORT_IS(UDP_PORT_TFTP)) {
303 /* This is the first point of call, but it adds a dynamic call */
304 udp_hash_add(MAX(uh_sport, uh_dport), dissect_tftp); /* Add to table */
305 dissect_tftp(pd, offset, fd, tree);
306 } else if (PORT_IS(UDP_PORT_RADIUS) ||
307 PORT_IS(UDP_PORT_RADACCT) ||
308 PORT_IS(UDP_PORT_RADIUS_NEW) ||
309 PORT_IS(UDP_PORT_RADACCT_NEW) ) {
310 dissect_radius(pd, offset, fd, tree);
311 } else if ( PORT_IS(UDP_PORT_L2TP)) {
312 dissect_l2tp(pd,offset,fd,tree);
313 } else if ( PORT_IS(UDP_PORT_ICP)) {
314 dissect_icp(pd,offset,fd,tree);
315 } else if ( PORT_IS(UDP_PORT_ICQ)) {
316 dissect_icq(pd,offset,fd,tree);
317 } else if (PORT_IS(UDP_PORT_WCCP) ) {
318 dissect_wccp(pd, offset, fd, tree);
320 /* OK, find a routine in the table, else use the default */
322 if ((dissect_routine = udp_find_hash_ent(uh_sport))) {
324 struct hash_struct *dr2 = udp_find_hash_ent(uh_dport);
326 if (dr2 == NULL) { /* Not in the table, add */
328 udp_hash_add(uh_dport, dissect_tftp);
332 dissect_routine -> dissect(pd, offset, fd, tree);
334 else if ((dissect_routine = udp_find_hash_ent(uh_dport))) {
336 dissect_routine -> dissect(pd, offset, fd, tree);
341 dissect_data(pd, offset, fd, tree);
347 proto_register_udp(void)
349 static hf_register_info hf[] = {
351 { "Source Port", "udp.srcport", FT_UINT16, BASE_DEC, NULL, 0x0,
355 { "Destination Port", "udp.dstport", FT_UINT16, BASE_DEC, NULL, 0x0,
359 { "Source or Destination Port", "udp.port", FT_UINT16, BASE_DEC, NULL, 0x0,
363 { "Length", "udp.length", FT_UINT16, BASE_DEC, NULL, 0x0,
367 { "Checksum", "udp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
370 static gint *ett[] = {
374 proto_udp = proto_register_protocol("User Datagram Protocol", "udp");
375 proto_register_field_array(proto_udp, hf, array_length(hf));
376 proto_register_subtree_array(ett, array_length(ett));