2 * Routines for UDP packet disassembly
4 * $Id: packet-udp.c,v 1.46 2000/01/15 00:22:33 gram 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_SRVLOC 427
79 #define UDP_PORT_PIM_RP_DISC 496
80 #define UDP_PORT_ISAKMP 500
81 #define UDP_PORT_WHO 513
82 #define UDP_PORT_RIP 520
83 #define UDP_PORT_RIPNG 521
84 #define UDP_PORT_NCP 524
85 #define UDP_PORT_VINES 573
86 #define UDP_PORT_RADIUS 1645
87 #define UDP_PORT_L2TP 1701
88 #define UDP_PORT_RADIUS_NEW 1812
89 #define UDP_PORT_RADACCT 1646
90 #define UDP_PORT_RADACCT_NEW 1813
91 #define UDP_PORT_HSRP 1985
92 #define UDP_PORT_ICP 3130
93 #define UDP_PORT_ICQ 4000
94 #define UDP_PORT_SAP 9875
95 #define UDP_PORT_RX_LOW 7000
96 #define UDP_PORT_RX_HIGH 7009
97 #define UDP_PORT_RX_AFS_BACKUPS 7021
98 #define UDP_PORT_WCCP 2048
102 void (*dissect)(const u_char *, int, frame_data *, proto_tree *);
103 struct hash_struct *next;
106 static struct hash_struct *hash_table[256];
109 * These routines are for UDP, will be generalized soon: RJS
111 * XXX - note that they should probably check the IP address as well as
112 * the port number, so that we don't mistakenly identify packets as, say,
113 * TFTP, merely because they have a source or destination port number
114 * equal to the port being used by a TFTP daemon on some machine other
115 * than the one they're going to or from.
118 struct hash_struct *udp_find_hash_ent(guint16 proto) {
120 int idx = proto % 256;
121 struct hash_struct *hash_ent = hash_table[idx];
123 while (hash_ent != NULL) {
125 if (hash_ent -> proto == proto)
128 hash_ent = hash_ent -> next;
136 void udp_hash_add(guint16 proto,
137 void (*dissect)(const u_char *, int, frame_data *, proto_tree *)) {
139 int idx = proto % 256; /* Simply take the remainder, hope for no collisions */
140 struct hash_struct *hash_ent = (struct hash_struct *)malloc(sizeof(struct hash_struct));
141 struct hash_struct *hash_ent2;
143 hash_ent -> proto = proto;
144 hash_ent -> dissect = dissect;
145 hash_ent -> next = NULL;
147 if (hash_ent == NULL) {
149 fprintf(stderr, "Could not allocate space for hash structure in dissect_udp\n");
153 if (hash_table[idx]) { /* Something, add on end */
155 hash_ent2 = hash_table[idx];
157 while (hash_ent2 -> next != NULL)
158 hash_ent2 = hash_ent2 -> next;
160 hash_ent2 -> next = hash_ent; /* Bad in pathalogical cases */
165 hash_table[idx] = hash_ent;
171 void init_dissect_udp(void) {
175 for (i = 0; i < 256; i++) {
177 hash_table[i] = NULL;
181 /* Now add the protocols we know about */
183 udp_hash_add(UDP_PORT_BOOTPS, dissect_bootp);
184 udp_hash_add(UDP_PORT_TFTP, dissect_tftp);
185 udp_hash_add(UDP_PORT_SAP, dissect_sap);
186 udp_hash_add(UDP_PORT_HSRP, dissect_hsrp);
187 udp_hash_add(UDP_PORT_PIM_RP_DISC, dissect_auto_rp);
188 udp_hash_add(UDP_PORT_TACACS, dissect_tacacs);
192 dissect_udp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
194 guint16 uh_sport, uh_dport, uh_ulen, uh_sum;
195 struct hash_struct *dissect_routine = NULL;
196 proto_tree *udp_tree;
199 if (!BYTES_ARE_IN_FRAME(offset, sizeof(e_udphdr))) {
200 dissect_data(pd, offset, fd, tree);
204 /* Avoids alignment problems on many architectures. */
205 memcpy(&uh, &pd[offset], sizeof(e_udphdr));
206 uh_sport = ntohs(uh.uh_sport);
207 uh_dport = ntohs(uh.uh_dport);
208 uh_ulen = ntohs(uh.uh_ulen);
209 uh_sum = ntohs(uh.uh_sum);
211 if (check_col(fd, COL_PROTOCOL))
212 col_add_str(fd, COL_PROTOCOL, "UDP");
213 if (check_col(fd, COL_INFO))
214 col_add_fstr(fd, COL_INFO, "Source port: %s Destination port: %s",
215 get_udp_port(uh_sport), get_udp_port(uh_dport));
218 ti = proto_tree_add_item(tree, proto_udp, offset, 8);
219 udp_tree = proto_item_add_subtree(ti, ett_udp);
221 proto_tree_add_item_format(udp_tree, hf_udp_srcport, offset, 2, uh_sport,
222 "Source port: %s (%u)", get_udp_port(uh_sport), uh_sport);
223 proto_tree_add_item_format(udp_tree, hf_udp_dstport, offset + 2, 2, uh_dport,
224 "Destination port: %s (%u)", get_udp_port(uh_dport), uh_dport);
226 proto_tree_add_item_hidden(udp_tree, hf_udp_port, offset, 2, uh_sport);
227 proto_tree_add_item_hidden(udp_tree, hf_udp_port, offset+2, 2, uh_dport);
229 proto_tree_add_item(udp_tree, hf_udp_length, offset + 4, 2, uh_ulen);
230 proto_tree_add_item_format(udp_tree, hf_udp_checksum, offset + 6, 2, uh_sum,
231 "Checksum: 0x%04x", uh_sum);
234 /* Skip over header */
238 pi.srcport = uh_sport;
239 pi.destport = uh_dport;
241 /* ONC RPC. We can't base this on anything in the UDP header; we have
242 to look at the payload. If "dissect_rpc()" returns TRUE, it was
243 an RPC packet, otherwise it's some other type of packet. */
244 if (dissect_rpc(pd, offset, fd, tree))
247 /* try to apply the plugins */
250 plugin *pt_plug = plugin_list;
254 if (pt_plug->enabled && !strcmp(pt_plug->protocol, "udp") &&
255 tree && dfilter_apply(pt_plug->filter, tree, pd)) {
256 pt_plug->dissector(pd, offset, fd, tree);
259 pt_plug = pt_plug->next;
265 /* XXX - we should do all of this through the table of ports. */
266 #define PORT_IS(port) (uh_sport == port || uh_dport == port)
267 if (PORT_IS(UDP_PORT_BOOTPS))
268 dissect_bootp(pd, offset, fd, tree);
269 else if (PORT_IS(UDP_PORT_DNS))
270 dissect_dns(pd, offset, fd, tree);
271 else if (PORT_IS(UDP_PORT_SRVLOC))
272 dissect_srvloc(pd, offset, fd, tree);
273 else if (PORT_IS(UDP_PORT_ISAKMP))
274 dissect_isakmp(pd, offset, fd, tree);
275 else if (PORT_IS(UDP_PORT_RIP)) {
276 /* we should check the source port too (RIP: UDP src and dst port 520) */
277 dissect_rip(pd, offset, fd, tree);
278 } else if (PORT_IS(UDP_PORT_RIPNG))
279 dissect_ripng(pd, offset, fd, tree);
280 else if (PORT_IS(UDP_PORT_NCP))
281 dissect_ncp(pd, offset, fd, tree);
282 else if (PORT_IS(UDP_PORT_NBNS))
283 dissect_nbns(pd, offset, fd, tree);
284 else if (PORT_IS(UDP_PORT_NBDGM))
285 dissect_nbdgm(pd, offset, fd, tree);
286 else if (PORT_IS(UDP_PORT_NTP))
287 dissect_ntp(pd, offset, fd, tree);
288 else if (PORT_IS(UDP_PORT_WHO))
289 dissect_who(pd, offset, fd, tree);
290 else if (PORT_IS(UDP_PORT_IPX)) /* RFC 1234 */
291 dissect_ipx(pd, offset, fd, tree);
292 else if ((uh_sport >= UDP_PORT_RX_LOW && uh_sport <= UDP_PORT_RX_HIGH) ||
293 (uh_dport >= UDP_PORT_RX_LOW && uh_dport <= UDP_PORT_RX_HIGH) ||
294 PORT_IS(UDP_PORT_RX_AFS_BACKUPS))
295 dissect_rx(pd, offset, fd, tree); /* transarc AFS's RX protocol */
296 else if (PORT_IS(UDP_PORT_SNMP))
297 dissect_snmp(pd, offset, fd, tree);
298 else if (PORT_IS(UDP_PORT_VINES)) {
299 /* FIXME: AFAIK, src and dst port must be the same */
300 dissect_vines_frp(pd, offset, fd, tree);
301 } else if (PORT_IS(UDP_PORT_TFTP)) {
302 /* This is the first point of call, but it adds a dynamic call */
303 udp_hash_add(MAX(uh_sport, uh_dport), dissect_tftp); /* Add to table */
304 dissect_tftp(pd, offset, fd, tree);
305 } else if (PORT_IS(UDP_PORT_RADIUS) ||
306 PORT_IS(UDP_PORT_RADACCT) ||
307 PORT_IS(UDP_PORT_RADIUS_NEW) ||
308 PORT_IS(UDP_PORT_RADACCT_NEW) ) {
309 dissect_radius(pd, offset, fd, tree);
310 } else if ( PORT_IS(UDP_PORT_L2TP)) {
311 dissect_l2tp(pd,offset,fd,tree);
312 } else if ( PORT_IS(UDP_PORT_ICP)) {
313 dissect_icp(pd,offset,fd,tree);
314 } else if ( PORT_IS(UDP_PORT_ICQ)) {
315 dissect_icq(pd,offset,fd,tree);
316 } else if (PORT_IS(UDP_PORT_WCCP) ) {
317 dissect_wccp(pd, offset, fd, tree);
319 /* OK, find a routine in the table, else use the default */
321 if ((dissect_routine = udp_find_hash_ent(uh_sport))) {
323 struct hash_struct *dr2 = udp_find_hash_ent(uh_dport);
325 if (dr2 == NULL) { /* Not in the table, add */
327 udp_hash_add(uh_dport, dissect_tftp);
331 dissect_routine -> dissect(pd, offset, fd, tree);
333 else if ((dissect_routine = udp_find_hash_ent(uh_dport))) {
335 dissect_routine -> dissect(pd, offset, fd, tree);
340 dissect_data(pd, offset, fd, tree);
346 proto_register_udp(void)
348 static hf_register_info hf[] = {
350 { "Source Port", "udp.srcport", FT_UINT16, BASE_DEC, NULL, 0x0,
354 { "Destination Port", "udp.dstport", FT_UINT16, BASE_DEC, NULL, 0x0,
358 { "Source or Destination Port", "udp.port", FT_UINT16, BASE_DEC, NULL, 0x0,
362 { "Length", "udp.length", FT_UINT16, BASE_DEC, NULL, 0x0,
366 { "Checksum", "udp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
369 static gint *ett[] = {
373 proto_udp = proto_register_protocol("User Datagram Protocol", "udp");
374 proto_register_field_array(proto_udp, hf, array_length(hf));
375 proto_register_subtree_array(ett, array_length(ett));