forked from osmocom/wireshark
Harald Welte
1e65231798
We so far only dumped the XID as raw hex bytes. Now we actually decode the header and internal data structure of the XID. Change-Id: I2901486222d84166291e071bc07cb82a2f480974 Reviewed-on: https://code.wireshark.org/review/18461 Petri-Dish: Michael Mann <mmann78@netscape.net> Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org> Reviewed-by: Michael Mann <mmann78@netscape.net>
485 lines
13 KiB
C
485 lines
13 KiB
C
/* packet-ehdlc.c
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* Routines for packet dissection of Ericsson HDLC as used in A-bis over IP
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* Copyright 2010-2012, 2016 by Harald Welte <laforge@gnumonks.org>
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*
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* This code is based on pure educational guesses while looking at protocol
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* traces, as there is no publicly available protocol description by Ericsson.
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* Even the name is a guess, since it looks quite a bit like HDLC and is used
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* by Ericsson, I called it EHDLC.
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "config.h"
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#include <epan/packet.h>
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#include <epan/xdlc.h>
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#include "packet-l2tp.h"
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void proto_register_ehdlc(void);
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void proto_reg_handoff_ehdlc(void);
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/* Initialize the protocol and registered fields */
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static int proto_ehdlc = -1;
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static int hf_ehdlc_data_len = -1;
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static int hf_ehdlc_csapi = -1;
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static int hf_ehdlc_ctei = -1;
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static int hf_ehdlc_sapi = -1;
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static int hf_ehdlc_tei = -1;
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static int hf_ehdlc_c_r = -1;
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static int hf_ehdlc_xid_payload = -1;
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static int hf_ehdlc_xid_win_tx = -1;
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static int hf_ehdlc_xid_win_rx = -1;
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static int hf_ehdlc_xid_ack_tmr_ms = -1;
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static int hf_ehdlc_xid_format_id = -1;
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static int hf_ehdlc_xid_group_id = -1;
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static int hf_ehdlc_xid_len = -1;
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static int hf_ehdlc_control = -1;
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static int hf_ehdlc_p = -1;
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static int hf_ehdlc_f = -1;
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static int hf_ehdlc_u_modifier_cmd = -1;
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static int hf_ehdlc_u_modifier_resp = -1;
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static int hf_ehdlc_ftype_s_u = -1;
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static int hf_ehdlc_n_r = -1;
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static int hf_ehdlc_n_s = -1;
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static int hf_ehdlc_p_ext = -1;
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static int hf_ehdlc_f_ext = -1;
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static int hf_ehdlc_s_ftype = -1;
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static int hf_ehdlc_ftype_i = -1;
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static int hf_ehdlc_ftype_s_u_ext = -1;
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static dissector_handle_t ehdlc_handle;
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/* Used only for U frames */
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static const xdlc_cf_items ehdlc_cf_items = {
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NULL,
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NULL,
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&hf_ehdlc_p,
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&hf_ehdlc_f,
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NULL,
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&hf_ehdlc_u_modifier_cmd,
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&hf_ehdlc_u_modifier_resp,
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NULL,
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&hf_ehdlc_ftype_s_u
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};
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/* Used only for I and S frames */
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static const xdlc_cf_items ehdlc_cf_items_ext = {
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&hf_ehdlc_n_r,
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&hf_ehdlc_n_s,
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&hf_ehdlc_p_ext,
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&hf_ehdlc_f_ext,
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&hf_ehdlc_s_ftype,
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NULL,
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NULL,
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&hf_ehdlc_ftype_i,
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&hf_ehdlc_ftype_s_u_ext,
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};
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/* Initialize the subtree pointers */
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static gint ett_ehdlc = -1;
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static gint ett_ehdlc_xid = -1;
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static gint ett_ehdlc_control = -1;
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enum {
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SUB_RSL,
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SUB_OML,
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SUB_TFP,
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SUB_PGSL,
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SUB_DATA,
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SUB_MAX
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};
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/* Determine TEI from Compressed TEI */
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static guint8 tei_from_ctei(guint8 ctei)
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{
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if (ctei < 12)
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return ctei;
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else
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return 60 + (ctei - 12);
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}
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static guint8 c_r_from_csapi(guint8 csapi)
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{
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switch (csapi) {
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case 1:
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case 6:
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return 1;
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default:
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return 0;
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}
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}
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static guint8 sapi_from_csapi(guint8 csapi)
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{
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switch (csapi) {
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case 0:
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case 1: /* RSL */
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return 0;
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case 2: /* TFP */
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return 10;
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case 3: /* TFP */
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return 11;
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case 4: /* P-GSL */
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return 12;
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case 5:
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case 6: /* OML */
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return 62;
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case 7:
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default:
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/* error! */
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return 0;
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}
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}
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static dissector_handle_t sub_handles[SUB_MAX];
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static int
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dissect_ehdlc_xid(proto_tree *tree, tvbuff_t *tvb, guint base_offset, guint len)
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{
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guint offset = base_offset;
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proto_item *ti;
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proto_tree *xid_tree;
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/* XID is formatted like ISO 8885, typically we see
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* something like
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* 82 format identifier
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* 80 group identifier
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* 00 09 length
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* 07 01 05 Window Size Tx
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* 09 01 04 Ack Timer (msec)
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* 08 01 05 Window Size Rx */
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ti = proto_tree_add_item(tree, hf_ehdlc_xid_payload,
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tvb, offset, len, ENC_NA);
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xid_tree = proto_item_add_subtree(ti, ett_ehdlc_xid);
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proto_tree_add_item(xid_tree, hf_ehdlc_xid_format_id, tvb, offset++, 1, ENC_NA);
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proto_tree_add_item(xid_tree, hf_ehdlc_xid_group_id, tvb, offset++, 1, ENC_NA);
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proto_tree_add_item(xid_tree, hf_ehdlc_xid_len, tvb, offset, 2, ENC_BIG_ENDIAN);
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offset += 2;
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while (tvb_reported_length_remaining(tvb, offset) >= 2) {
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guint8 iei = tvb_get_guint8(tvb, offset++);
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guint8 ie_len = tvb_get_guint8(tvb, offset++);
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switch (iei) {
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case 0x07:
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proto_tree_add_item(xid_tree, hf_ehdlc_xid_win_tx, tvb,
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offset, ie_len, ENC_NA);
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break;
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case 0x08:
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proto_tree_add_item(xid_tree, hf_ehdlc_xid_win_rx, tvb,
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offset, ie_len, ENC_NA);
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break;
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case 0x09:
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proto_tree_add_item(xid_tree, hf_ehdlc_xid_ack_tmr_ms, tvb,
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offset, ie_len, ENC_NA);
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break;
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}
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offset += ie_len;
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}
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return offset - base_offset;
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}
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/* Code to actually dissect the packets */
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static int
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dissect_ehdlc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
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{
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int offset = 4;
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "EHDLC");
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col_clear(pinfo->cinfo, COL_INFO);
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while (tvb_reported_length_remaining(tvb, offset) > 0) {
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proto_item *ti = NULL;
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proto_tree *ehdlc_tree = NULL;
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guint16 len, hdr2;
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guint8 csapi, ctei, sapi, tei, c_r;
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tvbuff_t *next_tvb;
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guint16 control;
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gboolean is_response = FALSE, is_extended = TRUE;
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gint header_length = 2; /* Address + Length field */
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hdr2 = tvb_get_guint16(tvb, offset, ENC_BIG_ENDIAN);
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len = hdr2 & 0x1FF;
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csapi = hdr2 >> 13;
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sapi = sapi_from_csapi(csapi);
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c_r = c_r_from_csapi(csapi);
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ctei = (hdr2 >> 9) & 0xF;
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tei = tei_from_ctei(ctei);
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if (tree) {
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/* Use MIN(...,...) in the following to prevent a premature */
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/* exception before we try to dissect whatever is available. */
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ti = proto_tree_add_protocol_format(tree, proto_ehdlc,
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tvb, offset, MIN(len, tvb_captured_length_remaining(tvb,offset)),
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"Ericsson HDLC protocol");
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ehdlc_tree = proto_item_add_subtree(ti, ett_ehdlc);
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proto_tree_add_item(ehdlc_tree, hf_ehdlc_csapi,
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tvb, offset, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(ehdlc_tree, hf_ehdlc_ctei,
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tvb, offset, 1, ENC_BIG_ENDIAN);
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proto_tree_add_uint_format_value(ehdlc_tree, hf_ehdlc_c_r,
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tvb, offset, 1, c_r, "%d", c_r);
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proto_tree_add_uint_format_value(ehdlc_tree, hf_ehdlc_sapi,
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tvb, offset, 1, sapi, "%d", sapi);
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proto_tree_add_uint_format_value(ehdlc_tree, hf_ehdlc_tei,
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tvb, offset, 1, tei, "%d", tei);
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proto_tree_add_item(ehdlc_tree, hf_ehdlc_data_len,
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tvb, offset, 2, ENC_BIG_ENDIAN);
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}
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if (sapi == 10 || sapi == 11) {
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/* Voice TRAU */
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next_tvb = tvb_new_subset_length(tvb, offset+2, len-2);
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call_dissector(sub_handles[SUB_TFP], next_tvb, pinfo, tree);
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offset += len;
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continue;
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} else if (sapi == 12) {
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/* GPRS TRAU */
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next_tvb = tvb_new_subset_length(tvb, offset+2, len-2);
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call_dissector(sub_handles[SUB_PGSL], next_tvb, pinfo, tree);
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offset += len;
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continue;
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}
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control = dissect_xdlc_control(tvb, offset+2, pinfo, ehdlc_tree, hf_ehdlc_control,
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ett_ehdlc_control, &ehdlc_cf_items, &ehdlc_cf_items_ext,
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NULL, NULL, is_response, is_extended, FALSE);
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header_length += XDLC_CONTROL_LEN(control, is_extended);
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if (XDLC_IS_INFORMATION(control)) {
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next_tvb = tvb_new_subset_length(tvb, offset+header_length,
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len-header_length);
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switch (sapi) {
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case 0:
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/* len == 4 seems to be some kind of ACK */
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if (len <= 4)
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break;
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call_dissector(sub_handles[SUB_RSL], next_tvb, pinfo, tree);
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break;
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case 62:
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/* len == 4 seems to be some kind of ACK */
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if (len <= 4)
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break;
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call_dissector(sub_handles[SUB_OML], next_tvb, pinfo, tree);
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break;
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default:
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call_dissector(sub_handles[SUB_DATA], next_tvb, pinfo, tree);
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break;
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}
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} else if (control == (XDLC_U | XDLC_XID)) {
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dissect_ehdlc_xid(ehdlc_tree, tvb, offset+header_length,
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len-header_length);
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}
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if (len == 0)
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len = 1;
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offset += len;
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}
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return tvb_captured_length(tvb);
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}
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void
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proto_register_ehdlc(void)
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{
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static hf_register_info hf[] = {
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{ &hf_ehdlc_data_len,
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{ "DataLen", "ehdlc.data_len",
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FT_UINT16, BASE_DEC, NULL, 0x1FF,
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"The length of the data (in bytes)", HFILL }
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},
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{ &hf_ehdlc_csapi,
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{ "Compressed SAPI", "ehdlc.csapi",
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FT_UINT8, BASE_DEC, NULL, 0xE0,
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NULL, HFILL}
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},
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{ &hf_ehdlc_ctei,
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{ "Compressed TEI", "ehdlc.ctei",
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FT_UINT8, BASE_DEC, NULL, 0x1E,
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NULL, HFILL}
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},
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{ &hf_ehdlc_sapi,
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{ "SAPI", "ehdlc.sapi",
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FT_UINT8, BASE_DEC, NULL, 0,
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NULL, HFILL }
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},
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{ &hf_ehdlc_tei,
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{ "TEI", "ehdlc.tei",
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FT_UINT8, BASE_DEC, NULL, 0,
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NULL, HFILL }
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},
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{ &hf_ehdlc_c_r,
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{ "C/R", "ehdlc.c_r",
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FT_UINT8, BASE_DEC, NULL, 0,
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NULL, HFILL }
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},
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{ &hf_ehdlc_xid_payload,
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{ "XID Payload", "ehdlc.xid_payload",
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FT_BYTES, BASE_NONE, NULL, 0,
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NULL, HFILL }
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},
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{ &hf_ehdlc_xid_win_tx,
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{ "Transmit Window", "ehdlc.xid.win_tx",
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FT_UINT8, BASE_DEC, NULL, 0,
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NULL, HFILL }
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},
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{ &hf_ehdlc_xid_win_rx,
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{ "Receive Window", "ehdlc.xid.win_rx",
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FT_UINT8, BASE_DEC, NULL, 0,
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NULL, HFILL }
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},
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{ &hf_ehdlc_xid_ack_tmr_ms,
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{ "Timer (ms)", "ehdlc.xid.ack_tmr_ms",
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FT_UINT8, BASE_DEC, NULL, 0,
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NULL, HFILL }
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},
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{ &hf_ehdlc_xid_format_id,
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{ "Format Identifier", "ehdlc.xid.format_id",
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FT_UINT8, BASE_HEX, NULL, 0,
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NULL, HFILL }
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},
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{ &hf_ehdlc_xid_group_id,
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{ "Group Identifier", "ehdlc.xid.group_id",
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FT_UINT8, BASE_HEX, NULL, 0,
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NULL, HFILL }
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},
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{ &hf_ehdlc_xid_len,
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{ "XID Length", "ehdlc.xid.len",
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FT_UINT16, BASE_DEC, NULL, 0,
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NULL, HFILL }
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},
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{ &hf_ehdlc_control,
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{ "Control Field", "ehdlc.control",
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FT_UINT16, BASE_HEX, NULL, 0,
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NULL, HFILL }
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},
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{ &hf_ehdlc_n_r,
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{ "N(R)", "ehdlc.control.n_r",
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FT_UINT16, BASE_DEC, NULL, XDLC_N_R_EXT_MASK,
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NULL, HFILL }
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},
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{ &hf_ehdlc_n_s,
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{ "N(S)", "ehdlc.control.n_s",
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FT_UINT16, BASE_DEC, NULL, XDLC_N_S_EXT_MASK,
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NULL, HFILL }
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},
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{ &hf_ehdlc_p,
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{ "Poll", "ehdlc.control.p",
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FT_BOOLEAN, 8, TFS(&tfs_set_notset), XDLC_P_F,
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NULL, HFILL }
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},
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{ &hf_ehdlc_p_ext,
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{ "Poll", "ehdlc.control.p",
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FT_BOOLEAN, 16, TFS(&tfs_set_notset), XDLC_P_F_EXT,
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NULL, HFILL }
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},
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{ &hf_ehdlc_f,
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{ "Final", "ehdlc.control.f",
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FT_BOOLEAN, 8, TFS(&tfs_set_notset), XDLC_P_F,
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NULL, HFILL }
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},
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{ &hf_ehdlc_f_ext,
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{ "Final", "ehdlc.control.f",
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FT_BOOLEAN, 16, TFS(&tfs_set_notset), XDLC_P_F_EXT,
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NULL, HFILL }
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},
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{ &hf_ehdlc_s_ftype,
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{ "Supervisory frame type", "ehdlc.control.s_ftype",
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FT_UINT16, BASE_HEX, VALS(stype_vals), XDLC_S_FTYPE_MASK,
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NULL, HFILL }
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},
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{ &hf_ehdlc_u_modifier_cmd,
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{ "Command", "ehdlc.control.u_modifier_cmd",
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FT_UINT8, BASE_HEX, VALS(modifier_vals_cmd), XDLC_U_MODIFIER_MASK,
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NULL, HFILL }
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},
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{ &hf_ehdlc_u_modifier_resp,
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{ "Response", "ehdlc.control.u_modifier_resp",
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FT_UINT8, BASE_HEX, VALS(modifier_vals_resp), XDLC_U_MODIFIER_MASK,
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NULL, HFILL }
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},
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{ &hf_ehdlc_ftype_i,
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{ "Frame Type", "ehdlc.control.ftype",
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FT_UINT16, BASE_HEX, VALS(ftype_vals), XDLC_I_MASK,
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NULL, HFILL }
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},
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{ &hf_ehdlc_ftype_s_u,
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{ "Frame Type", "ehdlc.control.ftype",
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FT_UINT8, BASE_HEX, VALS(ftype_vals), XDLC_S_U_MASK,
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NULL, HFILL }
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},
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{ &hf_ehdlc_ftype_s_u_ext,
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{ "Frame Type", "ehdlc.control.ftype",
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FT_UINT16, BASE_HEX, VALS(ftype_vals), XDLC_S_U_MASK,
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NULL, HFILL }
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},
|
|
};
|
|
|
|
static gint *ett[] = {
|
|
&ett_ehdlc,
|
|
&ett_ehdlc_xid,
|
|
&ett_ehdlc_control,
|
|
};
|
|
|
|
proto_ehdlc =
|
|
proto_register_protocol("Ericsson HDLC",
|
|
"Ericsson HDLC as used in A-bis over IP", "ehdlc");
|
|
|
|
proto_register_field_array(proto_ehdlc, hf, array_length(hf));
|
|
proto_register_subtree_array(ett, array_length(ett));
|
|
|
|
ehdlc_handle = register_dissector("ehdlc", dissect_ehdlc, proto_ehdlc);
|
|
}
|
|
|
|
void
|
|
proto_reg_handoff_ehdlc(void)
|
|
{
|
|
sub_handles[SUB_RSL] = find_dissector_add_dependency("gsm_abis_rsl", proto_ehdlc);
|
|
sub_handles[SUB_OML] = find_dissector_add_dependency("gsm_abis_oml", proto_ehdlc);
|
|
sub_handles[SUB_TFP] = find_dissector_add_dependency("gsm_abis_tfp", proto_ehdlc);
|
|
sub_handles[SUB_PGSL] = find_dissector_add_dependency("gsm_abis_pgsl", proto_ehdlc);
|
|
sub_handles[SUB_DATA] = find_dissector("data");
|
|
|
|
dissector_add_uint("l2tp.pw_type", L2TPv3_PROTOCOL_ERICSSON, ehdlc_handle);
|
|
}
|
|
|
|
/*
|
|
* Editor modelines - http://www.wireshark.org/tools/modelines.html
|
|
*
|
|
* Local variables:
|
|
* c-basic-offset: 8
|
|
* tab-width: 8
|
|
* indent-tabs-mode: t
|
|
* End:
|
|
*
|
|
* vi: set shiftwidth=8 tabstop=8 noexpandtab:
|
|
* :indentSize=8:tabSize=8:noTabs=false:
|
|
*/
|