2 * Routines for ARP packet disassembly
4 * $Id: packet-arp.c,v 1.16 1999/07/30 05:42:25 guy Exp $
6 * Ethereal - Network traffic analyzer
7 * By Gerald Combs <gerald@zing.org>
8 * Copyright 1998 Gerald Combs
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version 2
14 * of the License, or (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
30 #ifdef HAVE_SYS_TYPES_H
31 # include <sys/types.h>
38 static int proto_arp = -1;
40 /* Definitions taken from Linux "linux/if_arp.h" header file, and from
42 http://www.isi.edu/in-notes/iana/assignments/arp-parameters
46 /* ARP protocol HARDWARE identifiers. */
47 #define ARPHRD_NETROM 0 /* from KA9Q: NET/ROM pseudo */
48 #define ARPHRD_ETHER 1 /* Ethernet 10Mbps */
49 #define ARPHRD_EETHER 2 /* Experimental Ethernet */
50 #define ARPHRD_AX25 3 /* AX.25 Level 2 */
51 #define ARPHRD_PRONET 4 /* PROnet token ring */
52 #define ARPHRD_CHAOS 5 /* Chaosnet */
53 #define ARPHRD_IEEE802 6 /* IEEE 802.2 Ethernet/TR/TB */
54 #define ARPHRD_ARCNET 7 /* ARCnet */
55 #define ARPHRD_HYPERCH 8 /* Hyperchannel */
56 #define ARPHRD_LANSTAR 9 /* Lanstar */
57 #define ARPHRD_AUTONET 10 /* Autonet Short Address */
58 #define ARPHRD_LOCALTLK 11 /* Localtalk */
59 #define ARPHRD_LOCALNET 12 /* LocalNet (IBM PCNet/Sytek LocalNET) */
60 #define ARPHRD_ULTRALNK 13 /* Ultra link */
61 #define ARPHRD_SMDS 14 /* SMDS */
62 #define ARPHRD_DLCI 15 /* Frame Relay DLCI */
63 #define ARPHRD_ATM 16 /* ATM */
64 #define ARPHRD_HDLC 17 /* HDLC */
65 #define ARPHRD_FIBREC 18 /* Fibre Channel */
66 #define ARPHRD_ATM2225 19 /* ATM (RFC 2225) */
67 #define ARPHRD_SERIAL 20 /* Serial Line */
68 #define ARPHRD_ATM2 21 /* ATM */
69 #define ARPHRD_MS188220 22 /* MIL-STD-188-220 */
70 #define ARPHRD_METRICOM 23 /* Metricom STRIP */
71 #define ARPHRD_IEEE1394 24 /* IEEE 1394.1995 */
72 #define ARPHRD_MAPOS 25 /* MAPOS */
73 #define ARPHRD_TWINAX 26 /* Twinaxial */
74 #define ARPHRD_EUI_64 27 /* EUI-64 */
76 /* ARP / RARP structs and definitions */
78 #define ARPOP_REQUEST 1 /* ARP request. */
81 #define ARPOP_REPLY 2 /* ARP reply. */
83 /* Some OSes have different names, or don't define these at all */
84 #ifndef ARPOP_RREQUEST
85 #define ARPOP_RREQUEST 3 /* RARP request. */
88 #define ARPOP_RREPLY 4 /* RARP reply. */
92 arphrdaddr_to_str(guint8 *ad, int ad_len, guint16 type) {
93 if ((type == ARPHRD_ETHER || type == ARPHRD_EETHER || type == ARPHRD_IEEE802)
95 /* Ethernet address (or Experimental 3Mb Ethernet, or IEEE 802.x
96 address, which are the same type of address). */
97 return ether_to_str(ad);
99 return bytes_to_str(ad, ad_len);
103 arpproaddr_to_str(guint8 *ad, int ad_len, guint16 type) {
104 if (type == ETHERTYPE_IP && ad_len == 4) {
106 return ip_to_str(ad);
108 return bytes_to_str(ad, ad_len);
112 arphrdtype_to_str(guint16 hwtype, const char *fmt) {
113 static const value_string hrd_vals[] = {
114 {ARPHRD_NETROM, "NET/ROM pseudo" },
115 {ARPHRD_ETHER, "Ethernet" },
116 {ARPHRD_EETHER, "Experimental Ethernet"},
117 {ARPHRD_AX25, "AX.25" },
118 {ARPHRD_PRONET, "ProNET" },
119 {ARPHRD_CHAOS, "Chaos" },
120 {ARPHRD_IEEE802, "IEEE 802" },
121 {ARPHRD_ARCNET, "ARCNET" },
122 {ARPHRD_HYPERCH, "Hyperchannel" },
123 {ARPHRD_LANSTAR, "Lanstar" },
124 {ARPHRD_AUTONET, "Autonet Short Address"},
125 {ARPHRD_LOCALTLK, "Localtalk" },
126 {ARPHRD_LOCALNET, "LocalNet" },
127 {ARPHRD_ULTRALNK, "Ultra link" },
128 {ARPHRD_SMDS, "SMDS" },
129 {ARPHRD_DLCI, "Frame Relay DLCI" },
130 {ARPHRD_ATM, "ATM" },
131 {ARPHRD_HDLC, "HDLC" },
132 {ARPHRD_FIBREC, "Fibre Channel" },
133 {ARPHRD_ATM2225, "ATM (RFC 2225)" },
134 {ARPHRD_SERIAL, "Serial Line" },
135 {ARPHRD_ATM2, "ATM" },
136 {ARPHRD_MS188220, "MIL-STD-188-220" },
137 {ARPHRD_METRICOM, "Metricom STRIP" },
138 {ARPHRD_IEEE1394, "IEEE 1394.1995" },
139 {ARPHRD_MAPOS, "MAPOS" },
140 {ARPHRD_TWINAX, "Twinaxial" },
141 {ARPHRD_EUI_64, "EUI-64" },
144 return val_to_str(hwtype, hrd_vals, fmt);
147 /* Offsets of fields within an ARP packet. */
155 dissect_arp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
161 proto_tree *arp_tree;
164 int sha_offset, spa_offset, tha_offset, tpa_offset;
165 gchar *sha_str, *spa_str, *tha_str, *tpa_str;
166 static const value_string op_vals[] = {
167 {ARPOP_REQUEST, "ARP request" },
168 {ARPOP_REPLY, "ARP reply" },
169 {ARPOP_RREQUEST, "RARP request"},
170 {ARPOP_RREPLY, "RARP reply" },
173 /* To do: Check for {cap len,pkt len} < struct len */
174 ar_hrd = pntohs(&pd[offset + AR_HRD]);
175 ar_pro = pntohs(&pd[offset + AR_PRO]);
176 ar_hln = (guint8) pd[offset + AR_HLN];
177 ar_pln = (guint8) pd[offset + AR_PLN];
178 ar_op = pntohs(&pd[offset + AR_OP]);
180 /* Extract the addresses. */
181 sha_offset = offset + 8;
182 sha_str = arphrdaddr_to_str((guint8 *) &pd[sha_offset], ar_hln, ar_hrd);
183 spa_offset = sha_offset + ar_hln;
184 spa_str = arpproaddr_to_str((guint8 *) &pd[spa_offset], ar_pln, ar_pro);
185 tha_offset = spa_offset + ar_pln;
186 tha_str = arphrdaddr_to_str((guint8 *) &pd[tha_offset], ar_hln, ar_hrd);
187 tpa_offset = tha_offset + ar_hln;
188 tpa_str = arpproaddr_to_str((guint8 *) &pd[tpa_offset], ar_pln, ar_pro);
190 if (check_col(fd, COL_PROTOCOL)) {
191 if ((op_str = match_strval(ar_op, op_vals)))
192 col_add_str(fd, COL_PROTOCOL, op_str);
194 col_add_str(fd, COL_PROTOCOL, "ARP");
197 if (check_col(fd, COL_INFO)) {
200 col_add_fstr(fd, COL_INFO, "Who has %s? Tell %s",
204 col_add_fstr(fd, COL_INFO, "%s is at %s", spa_str, sha_str);
207 col_add_fstr(fd, COL_INFO, "Who is %s? Tell %s",
211 col_add_fstr(fd, COL_INFO, "%s is at %s", sha_str, spa_str);
214 col_add_fstr(fd, COL_INFO, "Unknown ARP opcode 0x%04x", ar_op);
220 if ((op_str = match_strval(ar_op, op_vals)))
221 ti = proto_tree_add_item_format(tree, proto_arp, offset,
222 8 + 2*ar_hln + 2*ar_pln, NULL, op_str);
224 ti = proto_tree_add_item_format(tree, proto_arp, offset,
225 8 + 2*ar_hln + 2*ar_pln, NULL, "Unknown ARP (opcode 0x%04x)", ar_op);
226 arp_tree = proto_item_add_subtree(ti, ETT_ARP);
227 proto_tree_add_text(arp_tree, offset + AR_HRD, 2,
228 "Hardware type: %s", arphrdtype_to_str(ar_hrd, "Unknown (0x%04x)"));
229 proto_tree_add_text(arp_tree, offset + AR_PRO, 2,
230 "Protocol type: %s", val_to_str(ar_pro, etype_vals, "Unknown (0x%04x)"));
231 proto_tree_add_text(arp_tree, offset + AR_HLN, 1,
232 "Hardware size: %d", ar_hln);
233 proto_tree_add_text(arp_tree, offset + AR_PLN, 1,
234 "Protocol size: %d", ar_pln);
235 proto_tree_add_text(arp_tree, offset + AR_OP, 2,
236 "Opcode: 0x%04x (%s)", ar_op, op_str ? op_str : "Unknown");
237 proto_tree_add_text(arp_tree, sha_offset, ar_hln,
238 "Sender hardware address: %s", sha_str);
239 proto_tree_add_text(arp_tree, spa_offset, ar_pln,
240 "Sender protocol address: %s", spa_str);
241 proto_tree_add_text(arp_tree, tha_offset, ar_hln,
242 "Target hardware address: %s", tha_str);
243 proto_tree_add_text(arp_tree, tpa_offset, ar_pln,
244 "Target protocol address: %s", tpa_str);
249 proto_register_arp(void)
251 /* static hf_register_info hf[] = {
253 { "Name", "arp.abbreviation", TYPE, VALS_POINTER }},
256 proto_arp = proto_register_protocol("Address Resolution Protocol", "arp");
257 /* proto_register_field_array(proto_arp, hf, array_length(hf));*/