2 * Routines for Cisco HDLC packet disassembly
6 * Wireshark - Network traffic analyzer
7 * By Gerald Combs <gerald@wireshark.org>
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.
30 #include <epan/packet.h>
31 #include <epan/etypes.h>
32 #include <epan/prefs.h>
33 #include <epan/chdlctypes.h>
34 #include <epan/nlpid.h>
35 #include <epan/addr_resolv.h>
36 #include "packet-chdlc.h"
37 #include "packet-ppp.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 * We thus have a separate dissector table for Cisco HDLC types.
75 * We could perhaps have that table hold only type values that
76 * wouldn't be in the Ethernet dissector table, and check that
77 * table first and the Ethernet dissector table if that fails.
79 #define CISCO_SLARP 0x8035 /* Cisco SLARP protocol */
81 static dissector_table_t subdissector_table;
83 static const value_string chdlc_address_vals[] = {
84 {CHDLC_ADDR_UNICAST, "Unicast"},
85 {CHDLC_ADDR_MULTICAST, "Multicast"},
89 const value_string chdlc_vals[] = {
90 {0x2000, "Cisco Discovery Protocol"},
92 {ETHERTYPE_IPv6, "IPv6"},
93 {CISCO_SLARP, "SLARP"},
94 {ETHERTYPE_DEC_LB, "DEC LanBridge"},
95 {CHDLCTYPE_BPDU, "Spanning Tree BPDU"},
96 {ETHERTYPE_ATALK, "Appletalk"},
97 {ETHERTYPE_AARP, "AARP"},
98 {ETHERTYPE_IPX, "Netware IPX/SPX"},
99 {ETHERTYPE_ETHBRIDGE, "Transparent Ethernet bridging" },
100 {CHDLCTYPE_OSI, "OSI" },
101 {ETHERTYPE_MPLS, "MPLS unicast"},
102 {ETHERTYPE_MPLS_MULTI, "MPLS multicast"},
107 capture_chdlc( const guchar *pd, int offset, int len, packet_counts *ld ) {
108 if (!BYTES_ARE_IN_FRAME(offset, len, 4)) {
112 switch (pntohs(&pd[offset + 2])) {
114 capture_ip(pd, offset + 4, len, ld);
123 chdlctype(guint16 chdlc_type, tvbuff_t *tvb, int offset_after_chdlctype,
124 packet_info *pinfo, proto_tree *tree, proto_tree *fh_tree,
131 proto_tree_add_uint(fh_tree, chdlctype_id, tvb,
132 offset_after_chdlctype - 2, 2, chdlc_type);
135 padbyte = tvb_get_guint8(tvb, offset_after_chdlctype);
136 if (chdlc_type == CHDLCTYPE_OSI &&
137 !( padbyte == NLPID_ISO8473_CLNP || /* older Juniper SW does not send a padbyte */
138 padbyte == NLPID_ISO9542_ESIS ||
139 padbyte == NLPID_ISO10589_ISIS)) {
140 /* There is a Padding Byte for CLNS protocols over Cisco HDLC */
141 proto_tree_add_text(fh_tree, tvb, offset_after_chdlctype, 1, "CLNS Padding: 0x%02x",
143 next_tvb = tvb_new_subset(tvb, offset_after_chdlctype + 1, -1, -1);
145 next_tvb = tvb_new_subset(tvb, offset_after_chdlctype, -1, -1);
148 /* do lookup with the subdissector table */
149 if (!dissector_try_port(subdissector_table, chdlc_type, next_tvb, pinfo, tree)) {
150 if (check_col(pinfo->cinfo, COL_PROTOCOL))
151 col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "0x%04x", chdlc_type);
152 call_dissector(data_handle,next_tvb, pinfo, tree);
156 static gint chdlc_fcs_decode = 0; /* 0 = No FCS, 1 = 16 bit FCS, 2 = 32 bit FCS */
159 dissect_chdlc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
162 proto_tree *fh_tree = NULL;
166 if (check_col(pinfo->cinfo, COL_PROTOCOL))
167 col_set_str(pinfo->cinfo, COL_PROTOCOL, "CHDLC");
168 if (check_col(pinfo->cinfo, COL_INFO))
169 col_clear(pinfo->cinfo, COL_INFO);
171 switch (pinfo->p2p_dir) {
174 if (check_col(pinfo->cinfo, COL_RES_DL_SRC))
175 col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DTE");
176 if (check_col(pinfo->cinfo, COL_RES_DL_DST))
177 col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DCE");
181 if (check_col(pinfo->cinfo, COL_RES_DL_SRC))
182 col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DCE");
183 if (check_col(pinfo->cinfo, COL_RES_DL_DST))
184 col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DTE");
188 if (check_col(pinfo->cinfo, COL_RES_DL_SRC))
189 col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "N/A");
190 if (check_col(pinfo->cinfo, COL_RES_DL_DST))
191 col_set_str(pinfo->cinfo, COL_RES_DL_DST, "N/A");
195 addr = tvb_get_guint8(tvb, 0);
196 proto = tvb_get_ntohs(tvb, 2);
199 ti = proto_tree_add_item(tree, proto_chdlc, tvb, 0, 4, FALSE);
200 fh_tree = proto_item_add_subtree(ti, ett_chdlc);
202 proto_tree_add_uint(fh_tree, hf_chdlc_addr, tvb, 0, 1, addr);
205 decode_fcs(tvb, fh_tree, chdlc_fcs_decode, 2);
207 chdlctype(proto, tvb, 4, pinfo, tree, fh_tree, hf_chdlc_proto);
211 proto_register_chdlc(void)
213 static hf_register_info hf[] = {
215 { "Address", "chdlc.address", FT_UINT8, BASE_HEX,
216 VALS(chdlc_address_vals), 0x0, "", HFILL }},
218 { "Protocol", "chdlc.protocol", FT_UINT16, BASE_HEX,
219 VALS(chdlc_vals), 0x0, "", HFILL }},
221 static gint *ett[] = {
225 module_t *chdlc_module;
227 proto_chdlc = proto_register_protocol("Cisco HDLC", "CHDLC", "chdlc");
228 proto_register_field_array(proto_chdlc, hf, array_length(hf));
229 proto_register_subtree_array(ett, array_length(ett));
231 /* subdissector code */
232 subdissector_table = register_dissector_table("chdlctype",
233 "Cisco HDLC frame type", FT_UINT16, BASE_HEX);
235 register_dissector("chdlc", dissect_chdlc, proto_chdlc);
237 /* Register the preferences for the chdlc protocol */
238 chdlc_module = prefs_register_protocol(proto_chdlc, NULL);
240 prefs_register_enum_preference(chdlc_module,
242 "CHDLC Frame Checksum Type",
243 "The type of CHDLC frame checksum (none, 16-bit, 32-bit)",
250 proto_reg_handoff_chdlc(void)
252 dissector_handle_t chdlc_handle;
254 data_handle = find_dissector("data");
255 chdlc_handle = find_dissector("chdlc");
256 dissector_add("wtap_encap", WTAP_ENCAP_CHDLC, chdlc_handle);
257 dissector_add("wtap_encap", WTAP_ENCAP_CHDLC_WITH_PHDR, chdlc_handle);
260 #define SLARP_REQUEST 0
261 #define SLARP_REPLY 1
262 #define SLARP_LINECHECK 2
264 static const value_string slarp_ptype_vals[] = {
265 {SLARP_REQUEST, "Request"},
266 {SLARP_REPLY, "Reply"},
267 {SLARP_LINECHECK, "Line keepalive"},
272 dissect_slarp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
275 proto_tree *slarp_tree = NULL;
279 guint32 yoursequence;
281 if (check_col(pinfo->cinfo, COL_PROTOCOL))
282 col_set_str(pinfo->cinfo, COL_PROTOCOL, "SLARP");
283 if (check_col(pinfo->cinfo, COL_INFO))
284 col_clear(pinfo->cinfo, COL_INFO);
286 code = tvb_get_ntohl(tvb, 0);
289 ti = proto_tree_add_item(tree, proto_slarp, tvb, 0, 14, FALSE);
290 slarp_tree = proto_item_add_subtree(ti, ett_slarp);
297 if (check_col(pinfo->cinfo, COL_INFO)) {
298 addr = tvb_get_ipv4(tvb, 4);
299 col_add_fstr(pinfo->cinfo, COL_INFO, "%s, from %s, mask %s",
300 val_to_str(code, slarp_ptype_vals, "Unknown (%d)"),
302 ip_to_str(tvb_get_ptr(tvb, 8, 4)));
305 proto_tree_add_uint(slarp_tree, hf_slarp_ptype, tvb, 0, 4, code);
306 proto_tree_add_item(slarp_tree, hf_slarp_address, tvb, 4, 4, FALSE);
307 proto_tree_add_text(slarp_tree, tvb, 8, 4,
308 "Netmask: %s", ip_to_str(tvb_get_ptr(tvb, 8, 4)));
312 case SLARP_LINECHECK:
313 mysequence = tvb_get_ntohl(tvb, 4);
314 yoursequence = tvb_get_ntohl(tvb, 8);
315 if (check_col(pinfo->cinfo, COL_INFO)) {
316 col_add_fstr(pinfo->cinfo, COL_INFO,
317 "%s, outgoing sequence %u, returned sequence %u",
318 val_to_str(code, slarp_ptype_vals, "Unknown (%d)"),
319 mysequence, yoursequence);
322 proto_tree_add_uint(slarp_tree, hf_slarp_ptype, tvb, 0, 4, code);
323 proto_tree_add_uint(slarp_tree, hf_slarp_mysequence, tvb, 4, 4,
325 proto_tree_add_uint(slarp_tree, hf_slarp_mysequence, tvb, 8, 4,
331 if (check_col(pinfo->cinfo, COL_INFO))
332 col_add_fstr(pinfo->cinfo, COL_INFO, "Unknown packet type 0x%08X", code);
334 proto_tree_add_uint(slarp_tree, hf_slarp_ptype, tvb, 0, 4, code);
335 call_dissector(data_handle, tvb_new_subset(tvb, 4, -1, -1), pinfo,
343 proto_register_slarp(void)
345 static hf_register_info hf[] = {
347 { "Packet type", "slarp.ptype", FT_UINT32, BASE_DEC,
348 VALS(slarp_ptype_vals), 0x0, NULL, HFILL }},
350 { "Address", "slarp.address", FT_IPv4, BASE_NONE,
351 NULL, 0x0, NULL, HFILL }},
352 /* XXX - need an FT_ for netmasks, which is like FT_IPV4 but doesn't
353 get translated to a host name. */
354 { &hf_slarp_mysequence,
355 { "Outgoing sequence number", "slarp.mysequence", FT_UINT32, BASE_DEC,
356 NULL, 0x0, NULL, HFILL }},
357 { &hf_slarp_yoursequence,
358 { "Returned sequence number", "slarp.yoursequence", FT_UINT32, BASE_DEC,
359 NULL, 0x0, NULL, HFILL }},
361 static gint *ett[] = {
366 proto_slarp = proto_register_protocol("Cisco SLARP", "SLARP", "slarp");
367 proto_register_field_array(proto_slarp, hf, array_length(hf));
368 proto_register_subtree_array(ett, array_length(ett));
372 proto_reg_handoff_slarp(void)
374 dissector_handle_t slarp_handle;
376 slarp_handle = create_dissector_handle(dissect_slarp, proto_slarp);
377 dissector_add("chdlctype", CISCO_SLARP, slarp_handle);