2 * Routines for UDP packet disassembly
4 * $Id: packet-udp.c,v 1.51 2000/02/23 22:28:50 oabad 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-auto_rp.h"
50 #include "packet-bootp.h"
51 #include "packet-dhis.h"
52 #include "packet-dns.h"
53 #include "packet-hsrp.h"
54 #include "packet-icp.h"
55 #include "packet-icq.h"
56 #include "packet-ipx.h"
57 #include "packet-isakmp.h"
58 #include "packet-l2tp.h"
59 #include "packet-nbns.h"
60 #include "packet-ncp.h"
61 #include "packet-ntp.h"
62 #include "packet-radius.h"
63 #include "packet-rip.h"
64 #include "packet-ripng.h"
65 #include "packet-rpc.h"
66 #include "packet-rx.h"
67 #include "packet-sap.h"
68 #include "packet-snmp.h"
69 #include "packet-srvloc.h"
70 #include "packet-tacacs.h"
71 #include "packet-tftp.h"
72 #include "packet-time.h"
73 #include "packet-vines.h"
74 #include "packet-wccp.h"
75 #include "packet-who.h"
77 static int proto_udp = -1;
78 static int hf_udp_srcport = -1;
79 static int hf_udp_dstport = -1;
80 static int hf_udp_port = -1;
81 static int hf_udp_length = -1;
82 static int hf_udp_checksum = -1;
84 static gint ett_udp = -1;
86 /* UDP structs and definitions */
88 typedef struct _e_udphdr {
95 /* UDP Ports -> should go in packet-udp.h */
97 #define UDP_PORT_TIME 37
98 #define UDP_PORT_TACACS 49
99 #define UDP_PORT_DNS 53
100 #define UDP_PORT_BOOTPS 67
101 #define UDP_PORT_TFTP 69
102 #define UDP_PORT_IPX 213
103 #define UDP_PORT_NTP 123
104 #define UDP_PORT_NBNS 137
105 #define UDP_PORT_NBDGM 138
106 #define UDP_PORT_SNMP 161
107 #define UDP_PORT_SNMP_TRAP 162
108 #define UDP_PORT_SRVLOC 427
109 #define UDP_PORT_PIM_RP_DISC 496
110 #define UDP_PORT_ISAKMP 500
111 #define UDP_PORT_WHO 513
112 #define UDP_PORT_RIP 520
113 #define UDP_PORT_RIPNG 521
114 #define UDP_PORT_NCP 524
115 #define UDP_PORT_VINES 573
116 #define UDP_PORT_RADIUS 1645
117 #define UDP_PORT_L2TP 1701
118 #define UDP_PORT_RADIUS_NEW 1812
119 #define UDP_PORT_RADACCT 1646
120 #define UDP_PORT_RADACCT_NEW 1813
121 #define UDP_PORT_HSRP 1985
122 #define UDP_PORT_ICP 3130
123 #define UDP_PORT_ICQ 4000
124 #define UDP_PORT_SAP 9875
125 #define UDP_PORT_RX_LOW 7000
126 #define UDP_PORT_RX_HIGH 7009
127 #define UDP_PORT_RX_AFS_BACKUPS 7021
128 #define UDP_PORT_WCCP 2048
129 #define UDP_PORT_DHIS1 58800
130 #define UDP_PORT_DHIS2 58801
134 void (*dissect)(const u_char *, int, frame_data *, proto_tree *);
135 struct hash_struct *next;
138 static struct hash_struct *hash_table[256];
141 * These routines are for UDP, will be generalized soon: RJS
143 * XXX - note that they should probably check the IP address as well as
144 * the port number, so that we don't mistakenly identify packets as, say,
145 * TFTP, merely because they have a source or destination port number
146 * equal to the port being used by a TFTP daemon on some machine other
147 * than the one they're going to or from.
150 struct hash_struct *udp_find_hash_ent(guint16 proto) {
152 int idx = proto % 256;
153 struct hash_struct *hash_ent = hash_table[idx];
155 while (hash_ent != NULL) {
157 if (hash_ent -> proto == proto)
160 hash_ent = hash_ent -> next;
168 void udp_hash_add(guint16 proto,
169 void (*dissect)(const u_char *, int, frame_data *, proto_tree *)) {
171 int idx = proto % 256; /* Simply take the remainder, hope for no collisions */
172 struct hash_struct *hash_ent = (struct hash_struct *)malloc(sizeof(struct hash_struct));
173 struct hash_struct *hash_ent2;
175 hash_ent -> proto = proto;
176 hash_ent -> dissect = dissect;
177 hash_ent -> next = NULL;
179 if (hash_ent == NULL) {
181 fprintf(stderr, "Could not allocate space for hash structure in dissect_udp\n");
185 if (hash_table[idx]) { /* Something, add on end */
187 hash_ent2 = hash_table[idx];
189 while (hash_ent2 -> next != NULL)
190 hash_ent2 = hash_ent2 -> next;
192 hash_ent2 -> next = hash_ent; /* Bad in pathalogical cases */
197 hash_table[idx] = hash_ent;
203 void init_dissect_udp(void) {
207 for (i = 0; i < 256; i++) {
209 hash_table[i] = NULL;
213 /* Now add the protocols we know about */
215 udp_hash_add(UDP_PORT_BOOTPS, dissect_bootp);
216 udp_hash_add(UDP_PORT_TFTP, dissect_tftp);
217 udp_hash_add(UDP_PORT_SAP, dissect_sap);
218 udp_hash_add(UDP_PORT_HSRP, dissect_hsrp);
219 udp_hash_add(UDP_PORT_PIM_RP_DISC, dissect_auto_rp);
220 udp_hash_add(UDP_PORT_TACACS, dissect_tacacs);
221 udp_hash_add(UDP_PORT_DHIS1, dissect_dhis);
222 udp_hash_add(UDP_PORT_DHIS2, dissect_dhis);
226 dissect_udp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
228 guint16 uh_sport, uh_dport, uh_ulen, uh_sum;
229 struct hash_struct *dissect_routine = NULL;
230 proto_tree *udp_tree;
233 if (!BYTES_ARE_IN_FRAME(offset, sizeof(e_udphdr))) {
234 dissect_data(pd, offset, fd, tree);
238 /* Avoids alignment problems on many architectures. */
239 memcpy(&uh, &pd[offset], sizeof(e_udphdr));
240 uh_sport = ntohs(uh.uh_sport);
241 uh_dport = ntohs(uh.uh_dport);
242 uh_ulen = ntohs(uh.uh_ulen);
243 uh_sum = ntohs(uh.uh_sum);
245 if (check_col(fd, COL_PROTOCOL))
246 col_add_str(fd, COL_PROTOCOL, "UDP");
247 if (check_col(fd, COL_INFO))
248 col_add_fstr(fd, COL_INFO, "Source port: %s Destination port: %s",
249 get_udp_port(uh_sport), get_udp_port(uh_dport));
252 ti = proto_tree_add_item(tree, proto_udp, offset, 8);
253 udp_tree = proto_item_add_subtree(ti, ett_udp);
255 proto_tree_add_item_format(udp_tree, hf_udp_srcport, offset, 2, uh_sport,
256 "Source port: %s (%u)", get_udp_port(uh_sport), uh_sport);
257 proto_tree_add_item_format(udp_tree, hf_udp_dstport, offset + 2, 2, uh_dport,
258 "Destination port: %s (%u)", get_udp_port(uh_dport), uh_dport);
260 proto_tree_add_item_hidden(udp_tree, hf_udp_port, offset, 2, uh_sport);
261 proto_tree_add_item_hidden(udp_tree, hf_udp_port, offset+2, 2, uh_dport);
263 proto_tree_add_item(udp_tree, hf_udp_length, offset + 4, 2, uh_ulen);
264 proto_tree_add_item_format(udp_tree, hf_udp_checksum, offset + 6, 2, uh_sum,
265 "Checksum: 0x%04x", uh_sum);
268 /* Skip over header */
272 pi.srcport = uh_sport;
273 pi.destport = uh_dport;
275 /* ONC RPC. We can't base this on anything in the UDP header; we have
276 to look at the payload. If "dissect_rpc()" returns TRUE, it was
277 an RPC packet, otherwise it's some other type of packet. */
278 if (dissect_rpc(pd, offset, fd, tree))
281 /* try to apply the plugins */
284 plugin *pt_plug = plugin_list;
288 if (pt_plug->enabled && !strcmp(pt_plug->protocol, "udp") &&
289 tree && dfilter_apply(pt_plug->filter, tree, pd)) {
290 pt_plug->dissector(pd, offset, fd, tree);
293 pt_plug = pt_plug->next;
299 /* XXX - we should do all of this through the table of ports. */
300 #define PORT_IS(port) (uh_sport == port || uh_dport == port)
301 if (PORT_IS(UDP_PORT_BOOTPS))
302 dissect_bootp(pd, offset, fd, tree);
303 else if (PORT_IS(UDP_PORT_DNS))
304 dissect_dns(pd, offset, fd, tree);
305 else if (PORT_IS(UDP_PORT_SRVLOC))
306 dissect_srvloc(pd, offset, fd, tree);
307 else if (PORT_IS(UDP_PORT_ISAKMP))
308 dissect_isakmp(pd, offset, fd, tree);
309 else if (PORT_IS(UDP_PORT_RIP)) {
310 /* we should check the source port too (RIP: UDP src and dst port 520) */
311 dissect_rip(pd, offset, fd, tree);
312 } else if (PORT_IS(UDP_PORT_RIPNG))
313 dissect_ripng(pd, offset, fd, tree);
314 else if (PORT_IS(UDP_PORT_NCP))
315 dissect_ncp(pd, offset, fd, tree); /* XXX -- need to handle nw_server_address */
316 else if (PORT_IS(UDP_PORT_NBNS))
317 dissect_nbns(pd, offset, fd, tree);
318 else if (PORT_IS(UDP_PORT_NBDGM))
319 dissect_nbdgm(pd, offset, fd, tree);
320 else if (PORT_IS(UDP_PORT_NTP))
321 dissect_ntp(pd, offset, fd, tree);
322 else if (PORT_IS(UDP_PORT_WHO))
323 dissect_who(pd, offset, fd, tree);
324 else if (PORT_IS(UDP_PORT_IPX)) /* RFC 1234 */
325 dissect_ipx(pd, offset, fd, tree);
326 else if ((uh_sport >= UDP_PORT_RX_LOW && uh_sport <= UDP_PORT_RX_HIGH) ||
327 (uh_dport >= UDP_PORT_RX_LOW && uh_dport <= UDP_PORT_RX_HIGH) ||
328 PORT_IS(UDP_PORT_RX_AFS_BACKUPS))
329 dissect_rx(pd, offset, fd, tree); /* transarc AFS's RX protocol */
330 else if (PORT_IS(UDP_PORT_SNMP) || PORT_IS(UDP_PORT_SNMP_TRAP))
331 dissect_snmp(pd, offset, fd, tree);
332 else if (PORT_IS(UDP_PORT_VINES)) {
333 /* FIXME: AFAIK, src and dst port must be the same */
334 dissect_vines_frp(pd, offset, fd, tree);
335 } else if (PORT_IS(UDP_PORT_TFTP)) {
336 /* This is the first point of call, but it adds a dynamic call */
337 udp_hash_add(MAX(uh_sport, uh_dport), dissect_tftp); /* Add to table */
338 dissect_tftp(pd, offset, fd, tree);
339 } else if (PORT_IS(UDP_PORT_TIME)) {
340 dissect_time(pd, offset, fd, tree);
341 } else if (PORT_IS(UDP_PORT_RADIUS) ||
342 PORT_IS(UDP_PORT_RADACCT) ||
343 PORT_IS(UDP_PORT_RADIUS_NEW) ||
344 PORT_IS(UDP_PORT_RADACCT_NEW) ) {
345 dissect_radius(pd, offset, fd, tree);
346 } else if ( PORT_IS(UDP_PORT_L2TP)) {
347 dissect_l2tp(pd,offset,fd,tree);
348 } else if ( PORT_IS(UDP_PORT_ICP)) {
349 dissect_icp(pd,offset,fd,tree);
350 } else if ( PORT_IS(UDP_PORT_ICQ)) {
351 dissect_icq(pd,offset,fd,tree);
352 } else if (PORT_IS(UDP_PORT_WCCP) ) {
353 dissect_wccp(pd, offset, fd, tree);
355 /* OK, find a routine in the table, else use the default */
357 if ((dissect_routine = udp_find_hash_ent(uh_sport))) {
359 struct hash_struct *dr2 = udp_find_hash_ent(uh_dport);
361 if (dr2 == NULL) { /* Not in the table, add */
363 udp_hash_add(uh_dport, dissect_tftp);
367 dissect_routine -> dissect(pd, offset, fd, tree);
369 else if ((dissect_routine = udp_find_hash_ent(uh_dport))) {
371 dissect_routine -> dissect(pd, offset, fd, tree);
376 dissect_data(pd, offset, fd, tree);
382 proto_register_udp(void)
384 static hf_register_info hf[] = {
386 { "Source Port", "udp.srcport", FT_UINT16, BASE_DEC, NULL, 0x0,
390 { "Destination Port", "udp.dstport", FT_UINT16, BASE_DEC, NULL, 0x0,
394 { "Source or Destination Port", "udp.port", FT_UINT16, BASE_DEC, NULL, 0x0,
398 { "Length", "udp.length", FT_UINT16, BASE_DEC, NULL, 0x0,
402 { "Checksum", "udp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
405 static gint *ett[] = {
409 proto_udp = proto_register_protocol("User Datagram Protocol", "udp");
410 proto_register_field_array(proto_udp, hf, array_length(hf));
411 proto_register_subtree_array(ett, array_length(ett));