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 * 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 {ETHERTYPE_IPv6, "IPv6"},
96 {CISCO_SLARP, "SLARP"},
97 {ETHERTYPE_DEC_LB, "DEC LanBridge"},
98 {CHDLCTYPE_BPDU, "Spanning Tree BPDU"},
99 {ETHERTYPE_ATALK, "Appletalk"},
100 {ETHERTYPE_AARP, "AARP"},
101 {ETHERTYPE_IPX, "Netware IPX/SPX"},
102 {ETHERTYPE_ETHBRIDGE, "Transparent Ethernet bridging" },
103 {CHDLCTYPE_OSI, "OSI" },
104 {ETHERTYPE_MPLS, "MPLS unicast"},
105 {ETHERTYPE_MPLS_MULTI, "MPLS multicast"},
110 capture_chdlc( const guchar *pd, int offset, int len, packet_counts *ld ) {
111 if (!BYTES_ARE_IN_FRAME(offset, len, 4)) {
115 switch (pntohs(&pd[offset + 2])) {
117 capture_ip(pd, offset + 4, len, ld);
126 chdlctype(guint16 chdlctype, tvbuff_t *tvb, int offset_after_chdlctype,
127 packet_info *pinfo, proto_tree *tree, proto_tree *fh_tree,
134 proto_tree_add_uint(fh_tree, chdlctype_id, tvb,
135 offset_after_chdlctype - 2, 2, chdlctype);
138 padbyte = tvb_get_guint8(tvb, offset_after_chdlctype);
139 if (chdlctype == CHDLCTYPE_OSI &&
140 !( padbyte == NLPID_ISO8473_CLNP || /* older Juniper SW does not send a padbyte */
141 padbyte == NLPID_ISO9542_ESIS ||
142 padbyte == NLPID_ISO10589_ISIS)) {
143 /* There is a Padding Byte for CLNS protocols over Cisco HDLC */
144 proto_tree_add_text(fh_tree, tvb, offset_after_chdlctype, 1, "CLNS Padding: 0x%02x",
146 next_tvb = tvb_new_subset(tvb, offset_after_chdlctype + 1, -1, -1);
148 next_tvb = tvb_new_subset(tvb, offset_after_chdlctype, -1, -1);
151 /* do lookup with the subdissector table */
152 if (!dissector_try_port(subdissector_table, chdlctype, next_tvb, pinfo, tree)) {
153 if (check_col(pinfo->cinfo, COL_PROTOCOL))
154 col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "0x%04x", chdlctype);
155 call_dissector(data_handle,next_tvb, pinfo, tree);
159 static gint chdlc_fcs_decode = 0; /* 0 = No FCS, 1 = 16 bit FCS, 2 = 32 bit FCS */
162 dissect_chdlc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
165 proto_tree *fh_tree = NULL;
169 if (check_col(pinfo->cinfo, COL_PROTOCOL))
170 col_set_str(pinfo->cinfo, COL_PROTOCOL, "CHDLC");
171 if (check_col(pinfo->cinfo, COL_INFO))
172 col_clear(pinfo->cinfo, COL_INFO);
174 switch (pinfo->p2p_dir) {
177 if (check_col(pinfo->cinfo, COL_RES_DL_SRC))
178 col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DTE");
179 if (check_col(pinfo->cinfo, COL_RES_DL_DST))
180 col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DCE");
184 if (check_col(pinfo->cinfo, COL_RES_DL_SRC))
185 col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DCE");
186 if (check_col(pinfo->cinfo, COL_RES_DL_DST))
187 col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DTE");
191 if (check_col(pinfo->cinfo, COL_RES_DL_SRC))
192 col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "N/A");
193 if (check_col(pinfo->cinfo, COL_RES_DL_DST))
194 col_set_str(pinfo->cinfo, COL_RES_DL_DST, "N/A");
198 addr = tvb_get_guint8(tvb, 0);
199 proto = tvb_get_ntohs(tvb, 2);
202 ti = proto_tree_add_item(tree, proto_chdlc, tvb, 0, 4, FALSE);
203 fh_tree = proto_item_add_subtree(ti, ett_chdlc);
205 proto_tree_add_uint(fh_tree, hf_chdlc_addr, tvb, 0, 1, addr);
208 decode_fcs(tvb, fh_tree, chdlc_fcs_decode, 2);
210 chdlctype(proto, tvb, 4, pinfo, tree, fh_tree, hf_chdlc_proto);
214 proto_register_chdlc(void)
216 static hf_register_info hf[] = {
218 { "Address", "chdlc.address", FT_UINT8, BASE_HEX,
219 VALS(chdlc_address_vals), 0x0, "", HFILL }},
221 { "Protocol", "chdlc.protocol", FT_UINT16, BASE_HEX,
222 VALS(chdlc_vals), 0x0, "", HFILL }},
224 static gint *ett[] = {
228 module_t *chdlc_module;
230 proto_chdlc = proto_register_protocol("Cisco HDLC", "CHDLC", "chdlc");
231 proto_register_field_array(proto_chdlc, hf, array_length(hf));
232 proto_register_subtree_array(ett, array_length(ett));
234 /* subdissector code */
235 subdissector_table = register_dissector_table("chdlctype",
236 "Cisco HDLC frame type", FT_UINT16, BASE_HEX);
238 register_dissector("chdlc", dissect_chdlc, proto_chdlc);
240 /* Register the preferences for the chdlc protocol */
241 chdlc_module = prefs_register_protocol(proto_chdlc, NULL);
243 prefs_register_enum_preference(chdlc_module,
245 "CHDLC Frame Checksum Type",
246 "The type of CHDLC frame checksum (none, 16-bit, 32-bit)",
253 proto_reg_handoff_chdlc(void)
255 dissector_handle_t chdlc_handle;
257 data_handle = find_dissector("data");
258 chdlc_handle = find_dissector("chdlc");
259 dissector_add("wtap_encap", WTAP_ENCAP_CHDLC, chdlc_handle);
260 dissector_add("wtap_encap", WTAP_ENCAP_CHDLC_WITH_PHDR, chdlc_handle);
263 #define SLARP_REQUEST 0
264 #define SLARP_REPLY 1
265 #define SLARP_LINECHECK 2
267 static const value_string slarp_ptype_vals[] = {
268 {SLARP_REQUEST, "Request"},
269 {SLARP_REPLY, "Reply"},
270 {SLARP_LINECHECK, "Line keepalive"},
275 dissect_slarp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
278 proto_tree *slarp_tree = NULL;
282 guint32 yoursequence;
284 if (check_col(pinfo->cinfo, COL_PROTOCOL))
285 col_set_str(pinfo->cinfo, COL_PROTOCOL, "SLARP");
286 if (check_col(pinfo->cinfo, COL_INFO))
287 col_clear(pinfo->cinfo, COL_INFO);
289 code = tvb_get_ntohl(tvb, 0);
292 ti = proto_tree_add_item(tree, proto_slarp, tvb, 0, 14, FALSE);
293 slarp_tree = proto_item_add_subtree(ti, ett_slarp);
300 if (check_col(pinfo->cinfo, COL_INFO)) {
301 address = tvb_get_ipv4(tvb, 4);
302 col_add_fstr(pinfo->cinfo, COL_INFO, "%s, from %s, mask %s",
303 match_strval(code, slarp_ptype_vals),
304 get_hostname(address),
305 ip_to_str(tvb_get_ptr(tvb, 8, 4)));
308 proto_tree_add_uint(slarp_tree, hf_slarp_ptype, tvb, 0, 4, code);
309 proto_tree_add_item(slarp_tree, hf_slarp_address, tvb, 4, 4, FALSE);
310 proto_tree_add_text(slarp_tree, tvb, 8, 4,
311 "Netmask: %s", ip_to_str(tvb_get_ptr(tvb, 8, 4)));
315 case SLARP_LINECHECK:
316 mysequence = tvb_get_ntohl(tvb, 4);
317 yoursequence = tvb_get_ntohl(tvb, 8);
318 if (check_col(pinfo->cinfo, COL_INFO)) {
319 col_add_fstr(pinfo->cinfo, COL_INFO,
320 "%s, outgoing sequence %u, returned sequence %u",
321 match_strval(code, slarp_ptype_vals),
322 mysequence, yoursequence);
325 proto_tree_add_uint(slarp_tree, hf_slarp_ptype, tvb, 0, 4, code);
326 proto_tree_add_uint(slarp_tree, hf_slarp_mysequence, tvb, 4, 4,
328 proto_tree_add_uint(slarp_tree, hf_slarp_mysequence, tvb, 8, 4,
334 if (check_col(pinfo->cinfo, COL_INFO))
335 col_add_fstr(pinfo->cinfo, COL_INFO, "Unknown packet type 0x%08X", code);
337 proto_tree_add_uint(slarp_tree, hf_slarp_ptype, tvb, 0, 4, code);
338 call_dissector(data_handle, tvb_new_subset(tvb, 4, -1, -1), pinfo,
346 proto_register_slarp(void)
348 static hf_register_info hf[] = {
350 { "Packet type", "slarp.ptype", FT_UINT32, BASE_DEC,
351 VALS(slarp_ptype_vals), 0x0, "", HFILL }},
353 { "Address", "slarp.address", FT_IPv4, BASE_NONE,
354 NULL, 0x0, "", HFILL }},
355 /* XXX - need an FT_ for netmasks, which is like FT_IPV4 but doesn't
356 get translated to a host name. */
357 { &hf_slarp_mysequence,
358 { "Outgoing sequence number", "slarp.mysequence", FT_UINT32, BASE_DEC,
359 NULL, 0x0, "", HFILL }},
360 { &hf_slarp_yoursequence,
361 { "Returned sequence number", "slarp.yoursequence", FT_UINT32, BASE_DEC,
362 NULL, 0x0, "", HFILL }},
364 static gint *ett[] = {
369 proto_slarp = proto_register_protocol("Cisco SLARP", "SLARP", "slarp");
370 proto_register_field_array(proto_slarp, hf, array_length(hf));
371 proto_register_subtree_array(ett, array_length(ett));
375 proto_reg_handoff_slarp(void)
377 dissector_handle_t slarp_handle;
379 slarp_handle = create_dissector_handle(dissect_slarp, proto_slarp);
380 dissector_add("chdlctype", CISCO_SLARP, slarp_handle);