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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
34 #include <epan/packet.h>
35 #include <epan/xdlc.h>
36 #include <epan/emem.h>
38 const value_string ftype_vals[] = {
39 { XDLC_I, "Information frame" },
40 { XDLC_S, "Supervisory frame" },
41 { XDLC_U, "Unnumbered frame" },
45 const value_string stype_vals[] = {
46 { XDLC_RR>>2, "Receiver ready" },
47 { XDLC_RNR>>2, "Receiver not ready" },
48 { XDLC_REJ>>2, "Reject" },
49 { XDLC_SREJ>>2, "Selective reject" },
53 static const value_string modifier_short_vals_cmd[] = {
56 { XDLC_DISC, "DISC" },
58 { XDLC_SNRM, "SNRM" },
59 { XDLC_SNRME, "SNRME" },
60 { XDLC_TEST, "TEST" },
62 { XDLC_FRMR, "FRMR" },
63 { XDLC_CFGR, "CFGR" },
64 { XDLC_SARM, "SARM" },
65 { XDLC_SABM, "SABM" },
66 { XDLC_SARME, "SARME" },
67 { XDLC_SABME, "SABME" },
68 { XDLC_RESET, "RESET" },
70 { XDLC_SNRME, "SNRME" },
75 const value_string modifier_vals_cmd[] = {
76 { XDLC_UI>>2, "Unnumbered Information" },
77 { XDLC_UP>>2, "Unnumbered Poll" },
78 { XDLC_DISC>>2, "Disconnect" },
79 { XDLC_UA>>2, "Unnumbered Acknowledge" },
80 { XDLC_SNRM>>2, "Set Normal Response Mode" },
81 { XDLC_TEST>>2, "Test" },
82 { XDLC_SIM>>2, "Set Initialization Mode" },
83 { XDLC_FRMR>>2, "Frame reject" },
84 { XDLC_CFGR>>2, "Configure" },
85 { XDLC_SARM>>2, "Set Asynchronous Response Mode" },
86 { XDLC_SABM>>2, "Set Asynchronous Balanced Mode" },
87 { XDLC_SARME>>2, "Set Asynchronous Response Mode Extended" },
88 { XDLC_SABME>>2, "Set Asynchronous Balanced Mode Extended" },
89 { XDLC_RESET>>2, "Reset" },
90 { XDLC_XID>>2, "Exchange identification" },
91 { XDLC_SNRME>>2, "Set Normal Response Mode Extended" },
92 { XDLC_BCN>>2, "Beacon" },
96 static const value_string modifier_short_vals_resp[] = {
101 { XDLC_SNRM, "SNRM" },
102 { XDLC_TEST, "TEST" },
104 { XDLC_FRMR, "FRMR" },
105 { XDLC_CFGR, "CFGR" },
107 { XDLC_SABM, "SABM" },
108 { XDLC_SARME, "SARME" },
109 { XDLC_SABME, "SABME" },
110 { XDLC_RESET, "RESET" },
112 { XDLC_SNRME, "SNRME" },
117 const value_string modifier_vals_resp[] = {
118 { XDLC_UI>>2, "Unnumbered Information" },
119 { XDLC_UP>>2, "Unnumbered Poll" },
120 { XDLC_RD>>2, "Request Disconnect" },
121 { XDLC_UA>>2, "Unnumbered Acknowledge" },
122 { XDLC_SNRM>>2, "Set Normal Response Mode" },
123 { XDLC_TEST>>2, "Test" },
124 { XDLC_RIM>>2, "Request Initialization Mode" },
125 { XDLC_FRMR>>2, "Frame reject" },
126 { XDLC_CFGR>>2, "Configure" },
127 { XDLC_DM>>2, "Disconnected mode" },
128 { XDLC_SABM>>2, "Set Asynchronous Balanced Mode" },
129 { XDLC_SARME>>2, "Set Asynchronous Response Mode Extended" },
130 { XDLC_SABME>>2, "Set Asynchronous Balanced Mode Extended" },
131 { XDLC_RESET>>2, "Reset" },
132 { XDLC_XID>>2, "Exchange identification" },
133 { XDLC_SNRME>>2, "Set Normal Response Mode Extended" },
134 { XDLC_BCN>>2, "Beacon" },
139 get_xdlc_control(const guchar *pd, int offset, gboolean is_extended)
143 switch (pd[offset] & 0x03) {
148 * Supervisory or Information frame.
151 control = pletohs(&pd[offset]);
153 control = pd[offset];
160 * XXX - is this two octets, with a P/F bit, in HDLC extended
161 * operation? It's one octet in LLC, even though the control
162 * field of I and S frames is a 2-byte extended-operation field
163 * in LLC. Given that there are no sequence numbers in the
164 * control field of a U frame, there doesn't appear to be any
165 * need for it to be 2 bytes in extended operation.
167 control = pd[offset];
174 * Check whether the control field of the packet looks valid.
177 check_xdlc_control(tvbuff_t *tvb, int offset,
178 const value_string *u_modifier_short_vals_cmd,
179 const value_string *u_modifier_short_vals_resp, gboolean is_response,
180 gboolean is_extended _U_)
184 if (!tvb_bytes_exist(tvb, offset, 1))
185 return FALSE; /* not enough data to check */
186 switch (tvb_get_guint8(tvb, offset) & 0x03) {
191 * No fields to check for validity here.
199 * XXX - is this two octets, with a P/F bit, in HDLC extended
200 * operation? It's one octet in LLC, even though the control
201 * field of I and S frames is a 2-byte extended-operation field
202 * in LLC. Given that there are no sequence numbers in the
203 * control field of a U frame, there doesn't appear to be any
204 * need for it to be 2 bytes in extended operation.
206 if (u_modifier_short_vals_cmd == NULL)
207 u_modifier_short_vals_cmd = modifier_short_vals_cmd;
208 if (u_modifier_short_vals_resp == NULL)
209 u_modifier_short_vals_resp = modifier_short_vals_resp;
210 control = tvb_get_guint8(tvb, offset);
212 if (match_strval(control & XDLC_U_MODIFIER_MASK,
213 u_modifier_short_vals_resp) == NULL)
214 return FALSE; /* unknown modifier */
216 if (match_strval(control & XDLC_U_MODIFIER_MASK,
217 u_modifier_short_vals_cmd) == NULL)
218 return FALSE; /* unknown modifier */
225 * No fields to check for validity here.
232 dissect_xdlc_control(tvbuff_t *tvb, int offset, packet_info *pinfo,
233 proto_tree *xdlc_tree, int hf_xdlc_control, gint ett_xdlc_control,
234 const xdlc_cf_items *cf_items_nonext, const xdlc_cf_items *cf_items_ext,
235 const value_string *u_modifier_short_vals_cmd,
236 const value_string *u_modifier_short_vals_resp, gboolean is_response,
237 gboolean is_extended, gboolean append_info)
241 const xdlc_cf_items *cf_items;
242 const char *control_format;
245 proto_tree *tc, *control_tree;
246 const gchar *frame_type = NULL;
247 const gchar *modifier;
250 switch (tvb_get_guint8(tvb, offset) & 0x03) {
257 control = tvb_get_letohs(tvb, offset);
259 cf_items = cf_items_ext;
260 control_format = "Control field: %s (0x%04X)";
262 control = tvb_get_guint8(tvb, offset);
264 cf_items = cf_items_nonext;
265 control_format = "Control field: %s (0x%02X)";
267 switch (control & XDLC_S_FTYPE_MASK) {
285 poll_final = (control & XDLC_P_F_EXT);
286 g_snprintf(info, 80, "S%s, func=%s, N(R)=%u",
288 (is_response ? " F" : " P") :
291 (control & XDLC_N_R_EXT_MASK) >> XDLC_N_R_EXT_SHIFT);
293 poll_final = (control & XDLC_P_F);
294 g_snprintf(info, 80, "S%s, func=%s, N(R)=%u",
296 (is_response ? " F" : " P") :
299 (control & XDLC_N_R_MASK) >> XDLC_N_R_SHIFT);
301 if (check_col(pinfo->cinfo, COL_INFO)) {
303 col_append_str(pinfo->cinfo, COL_INFO, ", ");
304 col_append_str(pinfo->cinfo, COL_INFO, info);
306 col_add_str(pinfo->cinfo, COL_INFO, info);
309 tc = proto_tree_add_uint_format(xdlc_tree, hf_xdlc_control, tvb,
310 offset, control_len, control, control_format, info, control);
311 control_tree = proto_item_add_subtree(tc, ett_xdlc_control);
312 proto_tree_add_uint(control_tree, *cf_items->hf_xdlc_n_r,
313 tvb, offset, control_len, control);
315 proto_tree_add_boolean(control_tree,
316 (is_response ? *cf_items->hf_xdlc_f :
317 *cf_items->hf_xdlc_p),
318 tvb, offset, control_len, control);
320 proto_tree_add_uint(control_tree, *cf_items->hf_xdlc_s_ftype,
321 tvb, offset, control_len, control);
322 /* This will always say it's a supervisory frame */
323 proto_tree_add_uint(control_tree, *cf_items->hf_xdlc_ftype_s_u,
324 tvb, offset, control_len, control);
332 * XXX - is this two octets, with a P/F bit, in HDLC extended
333 * operation? It's one octet in LLC, even though the control
334 * field of I and S frames is a 2-byte extended-operation field
335 * in LLC. Given that there are no sequence numbers in the
336 * control field of a U frame, there doesn't appear to be any
337 * need for it to be 2 bytes in extended operation.
339 if (u_modifier_short_vals_cmd == NULL)
340 u_modifier_short_vals_cmd = modifier_short_vals_cmd;
341 if (u_modifier_short_vals_resp == NULL)
342 u_modifier_short_vals_resp = modifier_short_vals_resp;
343 control = tvb_get_guint8(tvb, offset);
345 cf_items = cf_items_nonext;
346 control_format = "Control field: %s (0x%02X)";
348 modifier = val_to_str(control & XDLC_U_MODIFIER_MASK,
349 u_modifier_short_vals_resp, "Unknown");
351 modifier = val_to_str(control & XDLC_U_MODIFIER_MASK,
352 u_modifier_short_vals_cmd, "Unknown");
354 poll_final = (control & XDLC_P_F);
355 g_snprintf(info, 80, "U%s, func=%s",
357 (is_response ? " F" : " P") :
360 if (check_col(pinfo->cinfo, COL_INFO)) {
362 col_append_str(pinfo->cinfo, COL_INFO, ", ");
363 col_append_str(pinfo->cinfo, COL_INFO, info);
365 col_add_str(pinfo->cinfo, COL_INFO, info);
368 tc = proto_tree_add_uint_format(xdlc_tree, hf_xdlc_control, tvb,
369 offset, control_len, control, control_format, info, control);
370 control_tree = proto_item_add_subtree(tc, ett_xdlc_control);
372 proto_tree_add_boolean(control_tree,
373 (is_response ? *cf_items->hf_xdlc_f:
374 *cf_items->hf_xdlc_p),
375 tvb, offset, control_len, control);
377 proto_tree_add_uint(control_tree,
378 (is_response ? *cf_items->hf_xdlc_u_modifier_resp :
379 *cf_items->hf_xdlc_u_modifier_cmd),
380 tvb, offset, control_len, control);
381 /* This will always say it's an unnumbered frame */
382 proto_tree_add_uint(control_tree, *cf_items->hf_xdlc_ftype_s_u,
383 tvb, offset, control_len, control);
392 control = tvb_get_letohs(tvb, offset);
394 cf_items = cf_items_ext;
395 control_format = "Control field: %s (0x%04X)";
396 poll_final = (control & XDLC_P_F_EXT);
397 g_snprintf(info, 80, "I%s, N(R)=%u, N(S)=%u",
398 ((control & XDLC_P_F_EXT) ? " P" : ""),
399 (control & XDLC_N_R_EXT_MASK) >> XDLC_N_R_EXT_SHIFT,
400 (control & XDLC_N_S_EXT_MASK) >> XDLC_N_S_EXT_SHIFT);
402 control = tvb_get_guint8(tvb, offset);
404 cf_items = cf_items_nonext;
405 control_format = "Control field: %s (0x%02X)";
406 poll_final = (control & XDLC_P_F);
407 g_snprintf(info, 80, "I%s, N(R)=%u, N(S)=%u",
408 ((control & XDLC_P_F) ? " P" : ""),
409 (control & XDLC_N_R_MASK) >> XDLC_N_R_SHIFT,
410 (control & XDLC_N_S_MASK) >> XDLC_N_S_SHIFT);
412 if (check_col(pinfo->cinfo, COL_INFO)) {
414 col_append_str(pinfo->cinfo, COL_INFO, ", ");
415 col_append_str(pinfo->cinfo, COL_INFO, info);
417 col_add_str(pinfo->cinfo, COL_INFO, info);
420 tc = proto_tree_add_uint_format(xdlc_tree, hf_xdlc_control, tvb,
421 offset, control_len, control, control_format, info, control);
422 control_tree = proto_item_add_subtree(tc, ett_xdlc_control);
423 proto_tree_add_uint(control_tree, *cf_items->hf_xdlc_n_r,
424 tvb, offset, control_len, control);
425 proto_tree_add_uint(control_tree, *cf_items->hf_xdlc_n_s,
426 tvb, offset, control_len, control);
428 proto_tree_add_boolean(control_tree, *cf_items->hf_xdlc_p,
429 tvb, offset, control_len, control);
431 /* This will always say it's an information frame */
432 proto_tree_add_uint(control_tree, *cf_items->hf_xdlc_ftype_i,
433 tvb, offset, control_len, control);