245 lines
7.0 KiB
C
245 lines
7.0 KiB
C
/* packet-x75.c
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* Routines for X.75 frame disassembly
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* Manawyrm <git@tbspace.de>
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*
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* based on lapb dissector by
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* Olivier Abad <oabad@noos.fr>
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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
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "config.h"
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#include <epan/packet.h>
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#include <wiretap/wtap.h>
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#include <epan/xdlc.h>
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void proto_register_x75(void);
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void proto_reg_handoff_x75(void);
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#define X75_ADDRESS_SLP_STE_A 0x03
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#define X75_ADDRESS_SLP_STE_B 0x01
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#define X75_ADDRESS_MLP_STE_C 0x0F
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#define X75_ADDRESS_MLP_STE_D 0x07
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static int proto_x75;
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static int hf_x75_address;
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static int hf_x75_control;
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static int hf_x75_n_r;
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static int hf_x75_n_s;
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static int hf_x75_p;
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static int hf_x75_f;
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static int hf_x75_s_ftype;
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static int hf_x75_u_modifier_cmd;
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static int hf_x75_u_modifier_resp;
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static int hf_x75_ftype_i;
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static int hf_x75_ftype_s_u;
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static gint ett_x75;
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static gint ett_x75_control;
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static dissector_handle_t data_handle;
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static dissector_handle_t x75_handle;
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static const xdlc_cf_items x75_cf_items = {
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&hf_x75_n_r,
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&hf_x75_n_s,
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&hf_x75_p,
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&hf_x75_f,
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&hf_x75_s_ftype,
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&hf_x75_u_modifier_cmd,
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&hf_x75_u_modifier_resp,
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&hf_x75_ftype_i,
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&hf_x75_ftype_s_u
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};
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static int
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dissect_x75(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
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{
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proto_tree *x75_tree, *ti;
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guint16 control;
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int is_response;
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guint8 byte0;
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tvbuff_t *next_tvb;
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "X.75");
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col_set_str(pinfo->cinfo, COL_RES_NET_DST, "Broadcast");
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byte0 = tvb_get_guint8(tvb, 0);
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if (byte0 != X75_ADDRESS_SLP_STE_A && byte0 != X75_ADDRESS_SLP_STE_B &&
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byte0 != X75_ADDRESS_MLP_STE_C && byte0 != X75_ADDRESS_MLP_STE_D) /* invalid X.75 frame */
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{
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col_set_str(pinfo->cinfo, COL_INFO, "Invalid X.75 frame");
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if (tree)
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proto_tree_add_protocol_format(tree, proto_x75, tvb, 0, -1,
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"Invalid X.75 frame");
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return 1;
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}
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// Clear lower layer src/dst address types, so our custom names
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// are shown in the Packet List pane
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pinfo->src.type = AT_NONE;
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pinfo->dst.type = AT_NONE;
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switch (pinfo->p2p_dir) {
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case P2P_DIR_SENT:
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if (byte0 == X75_ADDRESS_SLP_STE_A || byte0 == X75_ADDRESS_SLP_STE_B)
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{
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col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "STE A");
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col_set_str(pinfo->cinfo, COL_RES_DL_DST, "STE B");
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}
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else
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{
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col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "STE C");
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col_set_str(pinfo->cinfo, COL_RES_DL_DST, "STE D");
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}
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if (byte0 == X75_ADDRESS_SLP_STE_A || byte0 == X75_ADDRESS_MLP_STE_C)
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is_response = TRUE;
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else
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is_response = FALSE;
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break;
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case P2P_DIR_RECV:
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if (byte0 == X75_ADDRESS_SLP_STE_A || byte0 == X75_ADDRESS_SLP_STE_B)
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{
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col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "STE B");
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col_set_str(pinfo->cinfo, COL_RES_DL_DST, "STE A");
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}
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else
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{
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col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "STE D");
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col_set_str(pinfo->cinfo, COL_RES_DL_DST, "STE C");
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}
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if (byte0 == X75_ADDRESS_SLP_STE_B || byte0 == X75_ADDRESS_MLP_STE_D)
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is_response = TRUE;
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else
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is_response = FALSE;
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break;
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default:
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is_response = FALSE;
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break;
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}
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if (is_response)
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{
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "X.75 RSP");
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}
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else
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{
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "X.75 CMD");
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}
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ti = proto_tree_add_protocol_format(tree, proto_x75, tvb, 0, 2,
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"X.75");
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x75_tree = proto_item_add_subtree(ti, ett_x75);
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proto_tree_add_uint(x75_tree, hf_x75_address, tvb, 0, 1, byte0);
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control = dissect_xdlc_control(tvb, 1, pinfo, x75_tree, hf_x75_control,
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ett_x75_control, &x75_cf_items, NULL, NULL, NULL,
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is_response, FALSE, FALSE);
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/* information frame ==> data */
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if (XDLC_IS_INFORMATION(control)) {
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next_tvb = tvb_new_subset_remaining(tvb, 2);
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int len = tvb_reported_length_remaining(next_tvb, 0);
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// limit number of bytes being shown in COL_INFO
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if (len > 128)
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len = 128;
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col_append_fstr(pinfo->cinfo, COL_INFO, ", %s", tvb_format_text(pinfo->pool, next_tvb, 0, len));
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call_dissector(data_handle, next_tvb, pinfo, tree);
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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_x75(void)
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{
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static hf_register_info hf[] = {
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{ &hf_x75_address,
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{ "Address", "x75.address", FT_UINT8, BASE_HEX, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_x75_control,
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{ "Control Field", "x75.control", FT_UINT8, BASE_HEX, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_x75_n_r,
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{ "N(R)", "x75.control.n_r", FT_UINT8, BASE_DEC,
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NULL, XDLC_N_R_MASK, NULL, HFILL }},
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{ &hf_x75_n_s,
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{ "N(S)", "x75.control.n_s", FT_UINT8, BASE_DEC,
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NULL, XDLC_N_S_MASK, NULL, HFILL }},
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{ &hf_x75_p,
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{ "Poll", "x75.control.p", FT_BOOLEAN, 8,
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TFS(&tfs_set_notset), XDLC_P_F, NULL, HFILL }},
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{ &hf_x75_f,
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{ "Final", "x75.control.f", FT_BOOLEAN, 8,
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TFS(&tfs_set_notset), XDLC_P_F, NULL, HFILL }},
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{ &hf_x75_s_ftype,
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{ "Supervisory frame type", "x75.control.s_ftype", FT_UINT8, BASE_HEX,
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VALS(stype_vals), XDLC_S_FTYPE_MASK, NULL, HFILL }},
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{ &hf_x75_u_modifier_cmd,
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{ "Command", "x75.control.u_modifier_cmd", FT_UINT8, BASE_HEX,
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VALS(modifier_vals_cmd), XDLC_U_MODIFIER_MASK, NULL, HFILL }},
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{ &hf_x75_u_modifier_resp,
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{ "Response", "x75.control.u_modifier_resp", FT_UINT8, BASE_HEX,
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VALS(modifier_vals_resp), XDLC_U_MODIFIER_MASK, NULL, HFILL }},
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{ &hf_x75_ftype_i,
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{ "Frame type", "x75.control.ftype", FT_UINT8, BASE_HEX,
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VALS(ftype_vals), XDLC_I_MASK, NULL, HFILL }},
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{ &hf_x75_ftype_s_u,
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{ "Frame type", "x75.control.ftype", FT_UINT8, BASE_HEX,
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VALS(ftype_vals), XDLC_S_U_MASK, NULL, HFILL }},
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};
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static gint *ett[] = {
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&ett_x75,
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&ett_x75_control,
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};
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proto_x75 = proto_register_protocol("Async data over ISDN (X.75)",
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"X.75", "x75");
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proto_register_field_array (proto_x75, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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x75_handle = register_dissector("x75", dissect_x75, proto_x75);
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}
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void
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proto_reg_handoff_x75(void)
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{
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data_handle = find_dissector("data");
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}
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/*
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* Editor modelines - https://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 4
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* vi: set shiftwidth=4 tabstop=8 expandtab:
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* :indentSize=4:tabSize=8:noTabs=true:
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*/
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