2 * Routines for use by various SDLC-derived protocols, such as HDLC
3 * and its derivatives LAPB, IEEE 802.2 LLC, etc..
7 * Wireshark - Network traffic analyzer
8 * By Gerald Combs <gerald@wireshark.org>
9 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
32 #include <epan/packet.h>
33 #include <epan/xdlc.h>
34 #include <epan/emem.h>
35 #include <wsutil/pint.h>
37 const value_string ftype_vals[] = {
38 { XDLC_I, "Information frame" },
39 { XDLC_S, "Supervisory frame" },
40 { XDLC_U, "Unnumbered frame" },
44 const value_string stype_vals[] = {
45 { XDLC_RR>>2, "Receiver ready" },
46 { XDLC_RNR>>2, "Receiver not ready" },
47 { XDLC_REJ>>2, "Reject" },
48 { XDLC_SREJ>>2, "Selective reject" },
52 static const value_string modifier_short_vals_cmd[] = {
55 { XDLC_DISC, "DISC" },
57 { XDLC_SNRM, "SNRM" },
58 { XDLC_SNRME, "SNRME" },
59 { XDLC_TEST, "TEST" },
61 { XDLC_FRMR, "FRMR" },
62 { XDLC_CFGR, "CFGR" },
63 { XDLC_SARM, "SARM" },
64 { XDLC_SABM, "SABM" },
65 { XDLC_SARME, "SARME" },
66 { XDLC_SABME, "SABME" },
67 { XDLC_RESET, "RESET" },
69 { XDLC_SNRME, "SNRME" },
74 const value_string modifier_vals_cmd[] = {
75 { XDLC_UI>>2, "Unnumbered Information" },
76 { XDLC_UP>>2, "Unnumbered Poll" },
77 { XDLC_DISC>>2, "Disconnect" },
78 { XDLC_UA>>2, "Unnumbered Acknowledge" },
79 { XDLC_SNRM>>2, "Set Normal Response Mode" },
80 { XDLC_TEST>>2, "Test" },
81 { XDLC_SIM>>2, "Set Initialization Mode" },
82 { XDLC_FRMR>>2, "Frame reject" },
83 { XDLC_CFGR>>2, "Configure" },
84 { XDLC_SARM>>2, "Set Asynchronous Response Mode" },
85 { XDLC_SABM>>2, "Set Asynchronous Balanced Mode" },
86 { XDLC_SARME>>2, "Set Asynchronous Response Mode Extended" },
87 { XDLC_SABME>>2, "Set Asynchronous Balanced Mode Extended" },
88 { XDLC_RESET>>2, "Reset" },
89 { XDLC_XID>>2, "Exchange identification" },
90 { XDLC_SNRME>>2, "Set Normal Response Mode Extended" },
91 { XDLC_BCN>>2, "Beacon" },
95 static const value_string modifier_short_vals_resp[] = {
100 { XDLC_SNRM, "SNRM" },
101 { XDLC_TEST, "TEST" },
103 { XDLC_FRMR, "FRMR" },
104 { XDLC_CFGR, "CFGR" },
106 { XDLC_SABM, "SABM" },
107 { XDLC_SARME, "SARME" },
108 { XDLC_SABME, "SABME" },
109 { XDLC_RESET, "RESET" },
111 { XDLC_SNRME, "SNRME" },
116 const value_string modifier_vals_resp[] = {
117 { XDLC_UI>>2, "Unnumbered Information" },
118 { XDLC_UP>>2, "Unnumbered Poll" },
119 { XDLC_RD>>2, "Request Disconnect" },
120 { XDLC_UA>>2, "Unnumbered Acknowledge" },
121 { XDLC_SNRM>>2, "Set Normal Response Mode" },
122 { XDLC_TEST>>2, "Test" },
123 { XDLC_RIM>>2, "Request Initialization Mode" },
124 { XDLC_FRMR>>2, "Frame reject" },
125 { XDLC_CFGR>>2, "Configure" },
126 { XDLC_DM>>2, "Disconnected mode" },
127 { XDLC_SABM>>2, "Set Asynchronous Balanced Mode" },
128 { XDLC_SARME>>2, "Set Asynchronous Response Mode Extended" },
129 { XDLC_SABME>>2, "Set Asynchronous Balanced Mode Extended" },
130 { XDLC_RESET>>2, "Reset" },
131 { XDLC_XID>>2, "Exchange identification" },
132 { XDLC_SNRME>>2, "Set Normal Response Mode Extended" },
133 { XDLC_BCN>>2, "Beacon" },
138 get_xdlc_control(const guchar *pd, int offset, gboolean is_extended)
142 switch (pd[offset] & 0x03) {
147 * Supervisory or Information frame.
150 control = pletoh16(&pd[offset]);
152 control = pd[offset];
159 * XXX - is this two octets, with a P/F bit, in HDLC extended
160 * operation? It's one octet in LLC, even though the control
161 * field of I and S frames is a 2-byte extended-operation field
162 * in LLC. Given that there are no sequence numbers in the
163 * control field of a U frame, there doesn't appear to be any
164 * need for it to be 2 bytes in extended operation.
166 control = pd[offset];
173 * Check whether the control field of the packet looks valid.
176 check_xdlc_control(tvbuff_t *tvb, int offset,
177 const value_string *u_modifier_short_vals_cmd,
178 const value_string *u_modifier_short_vals_resp, gboolean is_response,
179 gboolean is_extended _U_)
183 if (!tvb_bytes_exist(tvb, offset, 1))
184 return FALSE; /* not enough data to check */
185 switch (tvb_get_guint8(tvb, offset) & 0x03) {
190 * No fields to check for validity here.
198 * XXX - is this two octets, with a P/F bit, in HDLC extended
199 * operation? It's one octet in LLC, even though the control
200 * field of I and S frames is a 2-byte extended-operation field
201 * in LLC. Given that there are no sequence numbers in the
202 * control field of a U frame, there doesn't appear to be any
203 * need for it to be 2 bytes in extended operation.
205 if (u_modifier_short_vals_cmd == NULL)
206 u_modifier_short_vals_cmd = modifier_short_vals_cmd;
207 if (u_modifier_short_vals_resp == NULL)
208 u_modifier_short_vals_resp = modifier_short_vals_resp;
209 control = tvb_get_guint8(tvb, offset);
211 if (try_val_to_str(control & XDLC_U_MODIFIER_MASK,
212 u_modifier_short_vals_resp) == NULL)
213 return FALSE; /* unknown modifier */
215 if (try_val_to_str(control & XDLC_U_MODIFIER_MASK,
216 u_modifier_short_vals_cmd) == NULL)
217 return FALSE; /* unknown modifier */
224 * No fields to check for validity here.
231 dissect_xdlc_control(tvbuff_t *tvb, int offset, packet_info *pinfo,
232 proto_tree *xdlc_tree, int hf_xdlc_control, gint ett_xdlc_control,
233 const xdlc_cf_items *cf_items_nonext, const xdlc_cf_items *cf_items_ext,
234 const value_string *u_modifier_short_vals_cmd,
235 const value_string *u_modifier_short_vals_resp, gboolean is_response,
236 gboolean is_extended, gboolean append_info)
240 const xdlc_cf_items *cf_items;
241 const char *control_format;
244 proto_tree *tc, *control_tree;
245 const gchar *frame_type = NULL;
246 const gchar *modifier;
248 info=(char *)ep_alloc(80);
249 switch (tvb_get_guint8(tvb, offset) & 0x03) {
256 control = tvb_get_letohs(tvb, offset);
258 cf_items = cf_items_ext;
259 control_format = "Control field: %s (0x%04X)";
261 control = tvb_get_guint8(tvb, offset);
263 cf_items = cf_items_nonext;
264 control_format = "Control field: %s (0x%02X)";
266 switch (control & XDLC_S_FTYPE_MASK) {
284 poll_final = (control & XDLC_P_F_EXT);
285 g_snprintf(info, 80, "S%s, func=%s, N(R)=%u",
287 (is_response ? " F" : " P") :
290 (control & XDLC_N_R_EXT_MASK) >> XDLC_N_R_EXT_SHIFT);
292 poll_final = (control & XDLC_P_F);
293 g_snprintf(info, 80, "S%s, func=%s, N(R)=%u",
295 (is_response ? " F" : " P") :
298 (control & XDLC_N_R_MASK) >> XDLC_N_R_SHIFT);
301 col_append_str(pinfo->cinfo, COL_INFO, ", ");
302 col_append_str(pinfo->cinfo, COL_INFO, info);
304 col_add_str(pinfo->cinfo, COL_INFO, info);
307 tc = proto_tree_add_uint_format(xdlc_tree, hf_xdlc_control, tvb,
308 offset, control_len, control, control_format, info, control);
309 control_tree = proto_item_add_subtree(tc, ett_xdlc_control);
310 proto_tree_add_uint(control_tree, *cf_items->hf_xdlc_n_r,
311 tvb, offset, control_len, control);
313 proto_tree_add_boolean(control_tree,
314 (is_response ? *cf_items->hf_xdlc_f :
315 *cf_items->hf_xdlc_p),
316 tvb, offset, control_len, control);
318 proto_tree_add_uint(control_tree, *cf_items->hf_xdlc_s_ftype,
319 tvb, offset, control_len, control);
320 /* This will always say it's a supervisory frame */
321 proto_tree_add_uint(control_tree, *cf_items->hf_xdlc_ftype_s_u,
322 tvb, offset, control_len, control);
330 * XXX - is this two octets, with a P/F bit, in HDLC extended
331 * operation? It's one octet in LLC, even though the control
332 * field of I and S frames is a 2-byte extended-operation field
333 * in LLC. Given that there are no sequence numbers in the
334 * control field of a U frame, there doesn't appear to be any
335 * need for it to be 2 bytes in extended operation.
337 if (u_modifier_short_vals_cmd == NULL)
338 u_modifier_short_vals_cmd = modifier_short_vals_cmd;
339 if (u_modifier_short_vals_resp == NULL)
340 u_modifier_short_vals_resp = modifier_short_vals_resp;
341 control = tvb_get_guint8(tvb, offset);
343 cf_items = cf_items_nonext;
344 control_format = "Control field: %s (0x%02X)";
346 modifier = val_to_str(control & XDLC_U_MODIFIER_MASK,
347 u_modifier_short_vals_resp, "Unknown");
349 modifier = val_to_str(control & XDLC_U_MODIFIER_MASK,
350 u_modifier_short_vals_cmd, "Unknown");
352 poll_final = (control & XDLC_P_F);
353 g_snprintf(info, 80, "U%s, func=%s",
355 (is_response ? " F" : " P") :
359 col_append_str(pinfo->cinfo, COL_INFO, ", ");
360 col_append_str(pinfo->cinfo, COL_INFO, info);
362 col_add_str(pinfo->cinfo, COL_INFO, info);
365 tc = proto_tree_add_uint_format(xdlc_tree, hf_xdlc_control, tvb,
366 offset, control_len, control, control_format, info, control);
367 control_tree = proto_item_add_subtree(tc, ett_xdlc_control);
369 proto_tree_add_boolean(control_tree,
370 (is_response ? *cf_items->hf_xdlc_f:
371 *cf_items->hf_xdlc_p),
372 tvb, offset, control_len, control);
374 proto_tree_add_uint(control_tree,
375 (is_response ? *cf_items->hf_xdlc_u_modifier_resp :
376 *cf_items->hf_xdlc_u_modifier_cmd),
377 tvb, offset, control_len, control);
378 /* This will always say it's an unnumbered frame */
379 proto_tree_add_uint(control_tree, *cf_items->hf_xdlc_ftype_s_u,
380 tvb, offset, control_len, control);
389 control = tvb_get_letohs(tvb, offset);
391 cf_items = cf_items_ext;
392 control_format = "Control field: %s (0x%04X)";
393 poll_final = (control & XDLC_P_F_EXT);
394 g_snprintf(info, 80, "I%s, N(R)=%u, N(S)=%u",
395 ((control & XDLC_P_F_EXT) ? " P" : ""),
396 (control & XDLC_N_R_EXT_MASK) >> XDLC_N_R_EXT_SHIFT,
397 (control & XDLC_N_S_EXT_MASK) >> XDLC_N_S_EXT_SHIFT);
399 control = tvb_get_guint8(tvb, offset);
401 cf_items = cf_items_nonext;
402 control_format = "Control field: %s (0x%02X)";
403 poll_final = (control & XDLC_P_F);
404 g_snprintf(info, 80, "I%s, N(R)=%u, N(S)=%u",
405 ((control & XDLC_P_F) ? " P" : ""),
406 (control & XDLC_N_R_MASK) >> XDLC_N_R_SHIFT,
407 (control & XDLC_N_S_MASK) >> XDLC_N_S_SHIFT);
410 col_append_str(pinfo->cinfo, COL_INFO, ", ");
411 col_append_str(pinfo->cinfo, COL_INFO, info);
413 col_add_str(pinfo->cinfo, COL_INFO, info);
416 tc = proto_tree_add_uint_format(xdlc_tree, hf_xdlc_control, tvb,
417 offset, control_len, control, control_format, info, control);
418 control_tree = proto_item_add_subtree(tc, ett_xdlc_control);
419 proto_tree_add_uint(control_tree, *cf_items->hf_xdlc_n_r,
420 tvb, offset, control_len, control);
421 proto_tree_add_uint(control_tree, *cf_items->hf_xdlc_n_s,
422 tvb, offset, control_len, control);
424 proto_tree_add_boolean(control_tree, *cf_items->hf_xdlc_p,
425 tvb, offset, control_len, control);
427 /* This will always say it's an information frame */
428 proto_tree_add_uint(control_tree, *cf_items->hf_xdlc_ftype_i,
429 tvb, offset, control_len, control);