2 * Routines for Cisco HDLC packet disassembly
4 * $Id: packet-chdlc.c,v 1.10 2002/01/21 07:36:32 guy Exp $
6 * Ethereal - Network traffic analyzer
7 * By Gerald Combs <gerald@ethereal.com>
8 * Copyright 1998 Gerald Combs
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version 2
13 * of the License, or (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
29 #ifdef HAVE_SYS_TYPES_H
30 # include <sys/types.h>
34 #include <epan/packet.h>
36 #include <epan/resolv.h>
37 #include "packet-chdlc.h"
38 #include "packet-ip.h"
41 * See section 4.3.1 of RFC 1547, and
43 * http://www.nethelp.no/net/cisco-hdlc.txt
46 static int proto_chdlc = -1;
47 static int hf_chdlc_addr = -1;
48 static int hf_chdlc_proto = -1;
50 static gint ett_chdlc = -1;
52 static int proto_slarp = -1;
53 static int hf_slarp_ptype = -1;
54 static int hf_slarp_address = -1;
55 static int hf_slarp_mysequence = -1;
56 static int hf_slarp_yoursequence = -1;
58 static gint ett_slarp = -1;
60 static dissector_handle_t data_handle;
63 * Protocol types for the Cisco HDLC format.
65 * As per the above, according to RFC 1547, these are "standard 16 bit
66 * Ethernet protocol type code[s]", but 0x8035 is Reverse ARP, and
67 * that is (at least according to the Linux ISDN code) not the
68 * same as Cisco SLARP.
70 * In addition, 0x2000 is apparently the Cisco Discovery Protocol, but
71 * on Ethernet those are encapsulated inside SNAP with an OUI of
72 * OUI_CISCO, not OUI_ENCAP_ETHER.
74 * Perhaps we should set up a protocol table for those protocols
75 * that differ between Ethernet and Cisco HDLC, and have the PPP
76 * code first try that table and, if it finds nothing in that
77 * table, call "ethertype()". (Unfortunately, that means that -
78 * assuming we had a Cisco SLARP dissector - said dissector were
79 * disabled, SLARP packets would be dissected as Reverse ARP
80 * packets, not as data.)
82 #define CISCO_SLARP 0x8035 /* Cisco SLARP protocol */
84 static dissector_table_t subdissector_table;
86 static const value_string chdlc_address_vals[] = {
87 {CHDLC_ADDR_UNICAST, "Unicast"},
88 {CHDLC_ADDR_MULTICAST, "Multicast"},
92 const value_string chdlc_vals[] = {
93 {0x2000, "Cisco Discovery Protocol"},
95 {CISCO_SLARP, "SLARP"},
96 {ETHERTYPE_DEC_LB, "DEC LanBridge"},
97 {ETHERTYPE_ATALK, "Appletalk"},
98 {ETHERTYPE_AARP, "AARP"},
99 {ETHERTYPE_IPX, "Netware IPX/SPX"},
100 {ETHERTYPE_ETHBRIDGE, "Transparent Ethernet bridging" },
105 capture_chdlc( const u_char *pd, int offset, int len, packet_counts *ld ) {
106 if (!BYTES_ARE_IN_FRAME(offset, len, 2)) {
110 switch (pntohs(&pd[offset + 2])) {
112 capture_ip(pd, offset + 4, len, ld);
121 chdlctype(guint16 chdlctype, tvbuff_t *tvb, int offset_after_chdlctype,
122 packet_info *pinfo, proto_tree *tree, proto_tree *fh_tree,
128 proto_tree_add_uint(fh_tree, chdlctype_id, tvb,
129 offset_after_chdlctype - 2, 2, chdlctype);
132 next_tvb = tvb_new_subset(tvb, offset_after_chdlctype, -1, -1);
134 /* do lookup with the subdissector table */
135 if (!dissector_try_port(subdissector_table, chdlctype, next_tvb, pinfo, tree)) {
136 if (check_col(pinfo->cinfo, COL_PROTOCOL))
137 col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "0x%04x", chdlctype);
138 call_dissector(data_handle,next_tvb, pinfo, tree);
143 dissect_chdlc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
146 proto_tree *fh_tree = NULL;
150 if (check_col(pinfo->cinfo, COL_RES_DL_SRC))
151 col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "N/A");
152 if (check_col(pinfo->cinfo, COL_RES_DL_DST))
153 col_set_str(pinfo->cinfo, COL_RES_DL_DST, "N/A");
154 if (check_col(pinfo->cinfo, COL_PROTOCOL))
155 col_set_str(pinfo->cinfo, COL_PROTOCOL, "CHDLC");
156 if (check_col(pinfo->cinfo, COL_INFO))
157 col_clear(pinfo->cinfo, COL_INFO);
159 addr = tvb_get_guint8(tvb, 0);
160 proto = tvb_get_ntohs(tvb, 2);
163 ti = proto_tree_add_item(tree, proto_chdlc, tvb, 0, 4, FALSE);
164 fh_tree = proto_item_add_subtree(ti, ett_chdlc);
166 proto_tree_add_uint(fh_tree, hf_chdlc_addr, tvb, 0, 1, addr);
169 chdlctype(proto, tvb, 4, pinfo, tree, fh_tree, hf_chdlc_proto);
173 proto_register_chdlc(void)
175 static hf_register_info hf[] = {
177 { "Address", "chdlc.address", FT_UINT8, BASE_HEX,
178 VALS(chdlc_address_vals), 0x0, "", HFILL }},
180 { "Protocol", "chdlc.protocol", FT_UINT16, BASE_HEX,
181 VALS(chdlc_vals), 0x0, "", HFILL }},
183 static gint *ett[] = {
187 proto_chdlc = proto_register_protocol("Cisco HDLC", "CHDLC", "chdlc");
188 proto_register_field_array(proto_chdlc, hf, array_length(hf));
189 proto_register_subtree_array(ett, array_length(ett));
191 /* subdissector code */
192 subdissector_table = register_dissector_table("chdlctype",
193 "Cisco HDLC frame type", FT_UINT16, BASE_HEX);
195 register_dissector("chdlc", dissect_chdlc, proto_chdlc);
199 proto_reg_handoff_chdlc(void)
201 dissector_handle_t chdlc_handle;
203 data_handle = find_dissector("data");
204 chdlc_handle = find_dissector("chdlc");
205 dissector_add("wtap_encap", WTAP_ENCAP_CHDLC, chdlc_handle);
208 #define SLARP_REQUEST 0
209 #define SLARP_REPLY 1
210 #define SLARP_LINECHECK 2
212 static const value_string slarp_ptype_vals[] = {
213 {SLARP_REQUEST, "Request"},
214 {SLARP_REPLY, "Reply"},
215 {SLARP_LINECHECK, "Line keepalive"},
220 dissect_slarp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
223 proto_tree *slarp_tree = NULL;
226 guint32 yoursequence;
228 if (check_col(pinfo->cinfo, COL_PROTOCOL))
229 col_set_str(pinfo->cinfo, COL_PROTOCOL, "SLARP");
230 if (check_col(pinfo->cinfo, COL_INFO))
231 col_clear(pinfo->cinfo, COL_INFO);
233 code = tvb_get_ntohl(tvb, 0);
236 ti = proto_tree_add_item(tree, proto_slarp, tvb, 0, 14, FALSE);
237 slarp_tree = proto_item_add_subtree(ti, ett_slarp);
244 if (check_col(pinfo->cinfo, COL_INFO)) {
245 col_add_fstr(pinfo->cinfo, COL_INFO, "%s, from %s, mask %s",
246 match_strval(code, slarp_ptype_vals),
247 get_hostname(htonl(tvb_get_ntohl(tvb, 4))),
248 ip_to_str(tvb_get_ptr(tvb, 8, 4)));
251 proto_tree_add_uint(slarp_tree, hf_slarp_ptype, tvb, 0, 4, code);
252 proto_tree_add_item(slarp_tree, hf_slarp_address, tvb, 4, 4, FALSE);
253 proto_tree_add_text(slarp_tree, tvb, 8, 4,
254 "Netmask: %s", ip_to_str(tvb_get_ptr(tvb, 8, 4)));
258 case SLARP_LINECHECK:
259 mysequence = tvb_get_ntohl(tvb, 4);
260 yoursequence = tvb_get_ntohl(tvb, 8);
261 if (check_col(pinfo->cinfo, COL_INFO)) {
262 col_add_fstr(pinfo->cinfo, COL_INFO,
263 "%s, outgoing sequence %u, returned sequence %u",
264 match_strval(code, slarp_ptype_vals),
265 mysequence, yoursequence);
268 proto_tree_add_uint(slarp_tree, hf_slarp_ptype, tvb, 0, 4, code);
269 proto_tree_add_uint(slarp_tree, hf_slarp_mysequence, tvb, 4, 4,
271 proto_tree_add_uint(slarp_tree, hf_slarp_mysequence, tvb, 8, 4,
277 if (check_col(pinfo->cinfo, COL_INFO))
278 col_add_fstr(pinfo->cinfo, COL_INFO, "Unknown packet type 0x%08X", code);
280 proto_tree_add_uint(slarp_tree, hf_slarp_ptype, tvb, 0, 4, code);
281 call_dissector(data_handle,tvb_new_subset(tvb, 4,-1,tvb_reported_length_remaining(tvb,4)), pinfo, slarp_tree);
288 proto_register_slarp(void)
290 static hf_register_info hf[] = {
292 { "Packet type", "slarp.ptype", FT_UINT32, BASE_DEC,
293 VALS(slarp_ptype_vals), 0x0, "", HFILL }},
295 { "Address", "slarp.address", FT_IPv4, BASE_NONE,
296 NULL, 0x0, "", HFILL }},
297 /* XXX - need an FT_ for netmasks, which is like FT_IPV4 but doesn't
298 get translated to a host name. */
299 { &hf_slarp_mysequence,
300 { "Outgoing sequence number", "slarp.mysequence", FT_UINT32, BASE_DEC,
301 NULL, 0x0, "", HFILL }},
302 { &hf_slarp_yoursequence,
303 { "Returned sequence number", "slarp.yoursequence", FT_UINT32, BASE_DEC,
304 NULL, 0x0, "", HFILL }},
306 static gint *ett[] = {
310 proto_slarp = proto_register_protocol("Cisco SLARP", "SLARP", "slarp");
311 proto_register_field_array(proto_slarp, hf, array_length(hf));
312 proto_register_subtree_array(ett, array_length(ett));
316 proto_reg_handoff_slarp(void)
318 dissector_handle_t slarp_handle;
320 slarp_handle = create_dissector_handle(dissect_slarp, proto_slarp);
321 dissector_add("chdlctype", CISCO_SLARP, slarp_handle);