2 * Routines for UDP packet disassembly
4 * $Id: packet-udp.c,v 1.40 1999/12/05 02:32:39 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>
47 static int proto_udp = -1;
48 static int hf_udp_srcport = -1;
49 static int hf_udp_dstport = -1;
50 static int hf_udp_port = -1;
51 static int hf_udp_length = -1;
52 static int hf_udp_checksum = -1;
54 static gint ett_udp = -1;
56 /* UDP structs and definitions */
58 typedef struct _e_udphdr {
65 /* UDP Ports -> should go in packet-udp.h */
67 #define UDP_PORT_TACACS 49
68 #define UDP_PORT_DNS 53
69 #define UDP_PORT_BOOTPS 67
70 #define UDP_PORT_TFTP 69
71 #define UDP_PORT_IPX 213
72 #define UDP_PORT_NTP 123
73 #define UDP_PORT_NBNS 137
74 #define UDP_PORT_NBDGM 138
75 #define UDP_PORT_SNMP 161
76 #define UDP_PORT_PIM_RP_DISC 496
77 #define UDP_PORT_ISAKMP 500
78 #define UDP_PORT_RIP 520
79 #define UDP_PORT_RIPNG 521
80 #define UDP_PORT_VINES 573
81 #define UDP_PORT_RADIUS 1645
82 #define UDP_PORT_RADIUS_NEW 1812
83 #define UDP_PORT_RADACCT 1646
84 #define UDP_PORT_RADACCT_NEW 1813
85 #define UDP_PORT_HSRP 1985
86 #define UDP_PORT_ICP 3130
87 #define UDP_PORT_ICQ 4000
88 #define UDP_PORT_SAP 9875
89 #define UDP_PORT_RX_LOW 7000
90 #define UDP_PORT_RX_HIGH 7009
91 #define UDP_PORT_RX_AFS_BACKUPS 7021
95 void (*dissect)(const u_char *, int, frame_data *, proto_tree *);
96 struct hash_struct *next;
99 static struct hash_struct *hash_table[256];
102 * These routines are for UDP, will be generalized soon: RJS
104 * XXX - note that they should probably check the IP address as well as
105 * the port number, so that we don't mistakenly identify packets as, say,
106 * TFTP, merely because they have a source or destination port number
107 * equal to the port being used by a TFTP daemon on some machine other
108 * than the one they're going to or from.
111 struct hash_struct *udp_find_hash_ent(guint16 proto) {
113 int idx = proto % 256;
114 struct hash_struct *hash_ent = hash_table[idx];
116 while (hash_ent != NULL) {
118 if (hash_ent -> proto == proto)
121 hash_ent = hash_ent -> next;
129 void udp_hash_add(guint16 proto,
130 void (*dissect)(const u_char *, int, frame_data *, proto_tree *)) {
132 int idx = proto % 256; /* Simply take the remainder, hope for no collisions */
133 struct hash_struct *hash_ent = (struct hash_struct *)malloc(sizeof(struct hash_struct));
134 struct hash_struct *hash_ent2;
136 hash_ent -> proto = proto;
137 hash_ent -> dissect = dissect;
138 hash_ent -> next = NULL;
140 if (hash_ent == NULL) {
142 fprintf(stderr, "Could not allocate space for hash structure in dissect_udp\n");
146 if (hash_table[idx]) { /* Something, add on end */
148 hash_ent2 = hash_table[idx];
150 while (hash_ent2 -> next != NULL)
151 hash_ent2 = hash_ent2 -> next;
153 hash_ent2 -> next = hash_ent; /* Bad in pathalogical cases */
158 hash_table[idx] = hash_ent;
164 void init_dissect_udp(void) {
168 for (i = 0; i < 256; i++) {
170 hash_table[i] = NULL;
174 /* Now add the protocols we know about */
176 udp_hash_add(UDP_PORT_BOOTPS, dissect_bootp);
177 udp_hash_add(UDP_PORT_TFTP, dissect_tftp);
178 udp_hash_add(UDP_PORT_SAP, dissect_sap);
179 udp_hash_add(UDP_PORT_HSRP, dissect_hsrp);
180 udp_hash_add(UDP_PORT_PIM_RP_DISC, dissect_auto_rp);
181 udp_hash_add(UDP_PORT_TACACS, dissect_tacacs);
185 dissect_udp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
187 guint16 uh_sport, uh_dport, uh_ulen, uh_sum;
188 struct hash_struct *dissect_routine = NULL;
189 proto_tree *udp_tree;
192 if (!BYTES_ARE_IN_FRAME(offset, sizeof(e_udphdr))) {
193 dissect_data(pd, offset, fd, tree);
197 /* Avoids alignment problems on many architectures. */
198 memcpy(&uh, &pd[offset], sizeof(e_udphdr));
199 uh_sport = ntohs(uh.uh_sport);
200 uh_dport = ntohs(uh.uh_dport);
201 uh_ulen = ntohs(uh.uh_ulen);
202 uh_sum = ntohs(uh.uh_sum);
204 if (check_col(fd, COL_PROTOCOL))
205 col_add_str(fd, COL_PROTOCOL, "UDP");
206 if (check_col(fd, COL_INFO))
207 col_add_fstr(fd, COL_INFO, "Source port: %s Destination port: %s",
208 get_udp_port(uh_sport), get_udp_port(uh_dport));
211 ti = proto_tree_add_item(tree, proto_udp, offset, 8);
212 udp_tree = proto_item_add_subtree(ti, ett_udp);
214 proto_tree_add_item_format(udp_tree, hf_udp_srcport, offset, 2, uh_sport,
215 "Source port: %s (%u)", get_udp_port(uh_sport), uh_sport);
216 proto_tree_add_item_format(udp_tree, hf_udp_dstport, offset + 2, 2, uh_dport,
217 "Destination port: %s (%u)", get_udp_port(uh_dport), uh_dport);
219 proto_tree_add_item_hidden(udp_tree, hf_udp_port, offset, 2, uh_sport);
220 proto_tree_add_item_hidden(udp_tree, hf_udp_port, offset+2, 2, uh_dport);
222 proto_tree_add_item(udp_tree, hf_udp_length, offset + 4, 2, uh_ulen);
223 proto_tree_add_item_format(udp_tree, hf_udp_checksum, offset + 6, 2, uh_sum,
224 "Checksum: 0x%04x", uh_sum);
227 /* Skip over header */
231 pi.srcport = uh_sport;
232 pi.destport = uh_dport;
234 /* ONC RPC. We can't base this on anything in the UDP header; we have
235 to look at the payload. If "dissect_rpc()" returns TRUE, it was
236 an RPC packet, otherwise it's some other type of packet. */
237 if (dissect_rpc(pd, offset, fd, tree))
240 /* XXX - we should do all of this through the table of ports. */
241 #define PORT_IS(port) (uh_sport == port || uh_dport == port)
242 if (PORT_IS(UDP_PORT_BOOTPS))
243 dissect_bootp(pd, offset, fd, tree);
244 else if (PORT_IS(UDP_PORT_DNS))
245 dissect_dns(pd, offset, fd, tree);
246 else if (PORT_IS(UDP_PORT_ISAKMP))
247 dissect_isakmp(pd, offset, fd, tree);
248 else if (PORT_IS(UDP_PORT_RIP)) {
249 /* we should check the source port too (RIP: UDP src and dst port 520) */
250 dissect_rip(pd, offset, fd, tree);
251 } else if (PORT_IS(UDP_PORT_RIPNG))
252 dissect_ripng(pd, offset, fd, tree);
253 else if (PORT_IS(UDP_PORT_NBNS))
254 dissect_nbns(pd, offset, fd, tree);
255 else if (PORT_IS(UDP_PORT_NBDGM))
256 dissect_nbdgm(pd, offset, fd, tree);
257 else if (PORT_IS(UDP_PORT_NTP))
258 dissect_ntp(pd, offset, fd, tree);
259 else if (PORT_IS(UDP_PORT_IPX)) /* RFC 1234 */
260 dissect_ipx(pd, offset, fd, tree);
261 else if ((uh_sport >= UDP_PORT_RX_LOW && uh_sport <= UDP_PORT_RX_HIGH) ||
262 (uh_dport >= UDP_PORT_RX_LOW && uh_dport <= UDP_PORT_RX_HIGH) ||
263 PORT_IS(UDP_PORT_RX_AFS_BACKUPS))
264 dissect_rx(pd, offset, fd, tree); /* transarc AFS's RX protocol */
265 else if (PORT_IS(UDP_PORT_SNMP))
266 dissect_snmp(pd, offset, fd, tree);
267 else if (PORT_IS(UDP_PORT_VINES)) {
268 /* FIXME: AFAIK, src and dst port must be the same */
269 dissect_vines_frp(pd, offset, fd, tree);
270 } else if (PORT_IS(UDP_PORT_TFTP)) {
271 /* This is the first point of call, but it adds a dynamic call */
272 udp_hash_add(MAX(uh_sport, uh_dport), dissect_tftp); /* Add to table */
273 dissect_tftp(pd, offset, fd, tree);
274 } else if (PORT_IS(UDP_PORT_RADIUS) ||
275 PORT_IS(UDP_PORT_RADACCT) ||
276 PORT_IS(UDP_PORT_RADIUS_NEW) ||
277 PORT_IS(UDP_PORT_RADACCT_NEW) ) {
278 dissect_radius(pd, offset, fd, tree);
279 } else if ( PORT_IS(UDP_PORT_ICP)) {
280 dissect_icp(pd,offset,fd,tree);
281 } else if ( PORT_IS(UDP_PORT_ICQ)) {
282 dissect_icq(pd,offset,fd,tree);
284 /* OK, find a routine in the table, else use the default */
286 if ((dissect_routine = udp_find_hash_ent(uh_sport))) {
288 struct hash_struct *dr2 = udp_find_hash_ent(uh_dport);
290 if (dr2 == NULL) { /* Not in the table, add */
292 udp_hash_add(uh_dport, dissect_tftp);
296 dissect_routine -> dissect(pd, offset, fd, tree);
298 else if ((dissect_routine = udp_find_hash_ent(uh_dport))) {
300 dissect_routine -> dissect(pd, offset, fd, tree);
305 dissect_data(pd, offset, fd, tree);
311 proto_register_udp(void)
313 static hf_register_info hf[] = {
315 { "Source Port", "udp.srcport", FT_UINT16, BASE_DEC, NULL, 0x0,
319 { "Destination Port", "udp.dstport", FT_UINT16, BASE_DEC, NULL, 0x0,
323 { "Source or Destination Port", "udp.port", FT_UINT16, BASE_DEC, NULL, 0x0,
327 { "Length", "udp.length", FT_UINT16, BASE_DEC, NULL, 0x0,
331 { "Checksum", "udp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
334 static gint *ett[] = {
338 proto_udp = proto_register_protocol("User Datagram Protocol", "udp");
339 proto_register_field_array(proto_udp, hf, array_length(hf));
340 proto_register_subtree_array(ett, array_length(ett));