/* packet-v120.c

 * Routines for v120 frame disassembly

 * Bert Driehuis <driehuis@playbeing.org>

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998

 *

 * SPDX-License-Identifier: GPL-2.0-or-later

 */

#include "config.h"

#include <epan/packet.h>

#include <epan/xdlc.h>

#include <epan/tfs.h>

#include <wsutil/array.h>

void proto_register_v120(void);

static int proto_v120;

static int hf_v120_address;

static int hf_v120_rc;

static int hf_v120_lli;

static int hf_v120_ea0;

static int hf_v120_ea1;

static int hf_v120_control;

static int hf_v120_n_r;

static int hf_v120_n_s;

static int hf_v120_p;

static int hf_v120_p_ext;

static int hf_v120_f;

static int hf_v120_f_ext;

static int hf_v120_s_ftype;

static int hf_v120_u_modifier_cmd;

static int hf_v120_u_modifier_resp;

static int hf_v120_ftype_i;

static int hf_v120_ftype_s_u;

static int hf_v120_ftype_s_u_ext;

static int hf_v120_header8;

static int hf_v120_header_ext8;

static int hf_v120_header_break8;

static int hf_v120_header_error_control8;

static int hf_v120_header_segb8;

static int hf_v120_header_segf8;

static int hf_v120_header16;

static int hf_v120_header_ext16;

static int hf_v120_header_break16;

static int hf_v120_header_error_control16;

static int hf_v120_header_segb16;

static int hf_v120_header_segf16;

static int hf_v120_header_e;

static int hf_v120_header_dr;

static int hf_v120_header_sr;

static int hf_v120_header_rr;

static int ett_v120;

static int ett_v120_address;

static int ett_v120_control;

static int ett_v120_header;

static int dissect_v120_header(tvbuff_t *tvb, int offset, proto_tree *tree);

/* Used only for U frames */

static const xdlc_cf_items v120_cf_items = {

  NULL,

  NULL,

  &hf_v120_p,

  &hf_v120_f,

  NULL,

  &hf_v120_u_modifier_cmd,

  &hf_v120_u_modifier_resp,

  NULL,

  &hf_v120_ftype_s_u

};

/* Used only for I and S frames */

static const xdlc_cf_items v120_cf_items_ext = {

  &hf_v120_n_r,

  &hf_v120_n_s,

  &hf_v120_p_ext,

  &hf_v120_f_ext,

  &hf_v120_s_ftype,

  NULL,

  NULL,

  &hf_v120_ftype_i,

  &hf_v120_ftype_s_u_ext

};

static int

dissect_v120(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)

{

  proto_tree *v120_tree, *address_tree;

  proto_item *ti, *tc;

  int     is_response;

  int     v120len;

  uint8_t     byte0, byte1;

  uint16_t    control;

  tvbuff_t   *next_tvb;

  col_set_str(pinfo->cinfo, COL_PROTOCOL, "V.120");

  col_clear(pinfo->cinfo, COL_INFO);

  byte0 = tvb_get_uint8(tvb, 0);

  col_add_fstr(pinfo->cinfo, COL_RES_DL_SRC, "0x%02X", byte0);

  byte1 = tvb_get_uint8(tvb, 1);

  if ( ((byte0 & 0x01) != 0x00) && ((byte1 & 0x01) != 0x01) )

  {

    col_set_str(pinfo->cinfo, COL_INFO, "Invalid V.120 frame");

    if (tree)

      proto_tree_add_protocol_format(tree, proto_v120, tvb, 0, -1,

                  "Invalid V.120 frame");

    return 2;

  }

  if (pinfo->p2p_dir == P2P_DIR_SENT) {

    is_response = (byte0 & 0x02) ? false: true;

    col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DCE");

    col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DTE");

  } else {

    /* XXX - what if the direction is unknown? */

    is_response = (byte0 & 0x02) ? true : false;

    col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DTE");

    col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DCE");

  }

  ti = proto_tree_add_protocol_format(tree, proto_v120, tvb, 0, -1, "V.120");

  v120_tree = proto_item_add_subtree(ti, ett_v120);

  tc = proto_tree_add_item(v120_tree, hf_v120_address, tvb, 0, 2, ENC_BIG_ENDIAN);

  proto_item_append_text(tc, "LLI: %d C/R: %s",

      ((byte0 & 0xfc) << 5) | ((byte1 & 0xfe) >> 1),

      byte0 & 0x02 ? "R" : "C");

  address_tree = proto_item_add_subtree(tc, ett_v120_address);

  proto_tree_add_item(address_tree, hf_v120_rc, tvb, 0, 2, ENC_BIG_ENDIAN);

  proto_tree_add_item(address_tree, hf_v120_lli, tvb, 0, 2, ENC_BIG_ENDIAN);

  proto_tree_add_item(address_tree, hf_v120_ea0, tvb, 0, 2, ENC_BIG_ENDIAN);

  proto_tree_add_item(address_tree, hf_v120_ea1, tvb, 0, 2, ENC_BIG_ENDIAN);

  control = dissect_xdlc_control(tvb, 2, pinfo, v120_tree, hf_v120_control,

    ett_v120_control, &v120_cf_items, &v120_cf_items_ext,

    NULL, NULL, is_response, true, false);

  v120len = 2 + XDLC_CONTROL_LEN(control, true);

  if (tvb_bytes_exist(tvb, v120len, 1))

    v120len += dissect_v120_header(tvb, v120len, v120_tree);

  proto_item_set_len(ti, v120len);

  next_tvb = tvb_new_subset_remaining(tvb, v120len);

  call_data_dissector(next_tvb, pinfo, v120_tree);

  return tvb_captured_length(tvb);

}

static int

dissect_v120_header(tvbuff_t *tvb, int offset, proto_tree *tree)

{

  int         header_len;

  uint8_t     byte0;

  proto_tree *h_tree;

  proto_item *tc;

  byte0 = tvb_get_uint8(tvb, offset);

  if (byte0 & 0x80) {

    header_len = 1;

    tc = proto_tree_add_item(tree, hf_v120_header8, tvb, 0, 1, ENC_BIG_ENDIAN);

    h_tree = proto_item_add_subtree(tc, ett_v120_header);

    proto_tree_add_item(h_tree, hf_v120_header_ext8, tvb, 0, 1, ENC_NA);

    proto_tree_add_item(h_tree, hf_v120_header_break8, tvb, 0, 1, ENC_NA);

    proto_tree_add_item(h_tree, hf_v120_header_error_control8, tvb, 0, 1, ENC_BIG_ENDIAN);

    proto_tree_add_item(h_tree, hf_v120_header_segb8, tvb, 0, 1, ENC_NA);

    proto_tree_add_item(h_tree, hf_v120_header_segf8, tvb, 0, 1, ENC_NA);

  } else {

    header_len = 2;

    tc = proto_tree_add_item(tree, hf_v120_header16, tvb, 0, 2, ENC_BIG_ENDIAN);

    h_tree = proto_item_add_subtree(tc, ett_v120_header);

    proto_tree_add_item(h_tree, hf_v120_header_ext16, tvb, 0, 2, ENC_BIG_ENDIAN);

    proto_tree_add_item(h_tree, hf_v120_header_break16, tvb, 0, 2, ENC_BIG_ENDIAN);

    proto_tree_add_item(h_tree, hf_v120_header_error_control16, tvb, 0, 2, ENC_BIG_ENDIAN);

    proto_tree_add_item(h_tree, hf_v120_header_segb16, tvb, 0, 2, ENC_BIG_ENDIAN);

    proto_tree_add_item(h_tree, hf_v120_header_segf16, tvb, 0, 2, ENC_BIG_ENDIAN);

    proto_tree_add_item(h_tree, hf_v120_header_e, tvb, 0, 2, ENC_BIG_ENDIAN);

    proto_tree_add_item(h_tree, hf_v120_header_dr, tvb, 0, 2, ENC_BIG_ENDIAN);

    proto_tree_add_item(h_tree, hf_v120_header_sr, tvb, 0, 2, ENC_BIG_ENDIAN);

    proto_tree_add_item(h_tree, hf_v120_header_rr, tvb, 0, 2, ENC_BIG_ENDIAN);

  }

  proto_item_append_text(tc, " B: %d F: %d",

             byte0 & 0x02 ? 1:0, byte0 & 0x01 ? 1:0);

  return header_len;

}

void

proto_register_v120(void)

{

  static hf_register_info hf[] = {

    { &hf_v120_address,

      { "Link Address", "v120.address", FT_UINT16, BASE_HEX, NULL,

        0x0, NULL, HFILL }},

    { &hf_v120_rc,

      { "R/C", "v120.rc", FT_BOOLEAN, 16, TFS(&tfs_response_command),

        0x0002, NULL, HFILL }},

    { &hf_v120_lli,

      { "LLI", "v120.lli", FT_UINT16, BASE_HEX, NULL,

        0xfefc, NULL, HFILL }},

    { &hf_v120_ea0,

      { "EA0", "v120.ea0", FT_BOOLEAN, 16, TFS(&tfs_error_ok),

        0x0001, NULL, HFILL }},

    { &hf_v120_ea1,

      { "EA1", "v120.ea1", FT_BOOLEAN, 16, TFS(&tfs_ok_error),

        0x0100, NULL, HFILL }},

    { &hf_v120_control,

      { "Control Field", "v120.control", FT_UINT16, BASE_HEX, NULL, 0x0,

        NULL, HFILL }},

    { &hf_v120_n_r,

      { "N(R)", "v120.control.n_r", FT_UINT16, BASE_DEC,

        NULL, XDLC_N_R_EXT_MASK, NULL, HFILL }},

    { &hf_v120_n_s,

      { "N(S)", "v120.control.n_s", FT_UINT16, BASE_DEC,

        NULL, XDLC_N_S_EXT_MASK, NULL, HFILL }},

    { &hf_v120_p,

      { "Poll", "v120.control.p", FT_BOOLEAN, 8,

        TFS(&tfs_set_notset), XDLC_P_F, NULL, HFILL }},

    { &hf_v120_p_ext,

      { "Poll", "v120.control.p", FT_BOOLEAN, 16,

        TFS(&tfs_set_notset), XDLC_P_F_EXT, NULL, HFILL }},

    { &hf_v120_f,

      { "Final", "v120.control.f", FT_BOOLEAN, 8,

        TFS(&tfs_set_notset), XDLC_P_F, NULL, HFILL }},

    { &hf_v120_f_ext,

      { "Final", "v120.control.f", FT_BOOLEAN, 16,

        TFS(&tfs_set_notset), XDLC_P_F_EXT, NULL, HFILL }},

    { &hf_v120_s_ftype,

      { "Supervisory frame type", "v120.control.s_ftype", FT_UINT16, BASE_HEX,

        VALS(stype_vals), XDLC_S_FTYPE_MASK, NULL, HFILL }},

    { &hf_v120_u_modifier_cmd,

      { "Command", "v120.control.u_modifier_cmd", FT_UINT8, BASE_HEX,

        VALS(modifier_vals_cmd), XDLC_U_MODIFIER_MASK, NULL, HFILL }},

    { &hf_v120_u_modifier_resp,

      { "Response", "v120.control.u_modifier_resp", FT_UINT8, BASE_HEX,

        VALS(modifier_vals_resp), XDLC_U_MODIFIER_MASK, NULL, HFILL }},

    { &hf_v120_ftype_i,

      { "Frame type", "v120.control.ftype", FT_UINT16, BASE_HEX,

        VALS(ftype_vals), XDLC_I_MASK, NULL, HFILL }},

    { &hf_v120_ftype_s_u,

      { "Frame type", "v120.control.ftype", FT_UINT8, BASE_HEX,

        VALS(ftype_vals), XDLC_S_U_MASK, NULL, HFILL }},

    { &hf_v120_ftype_s_u_ext,

      { "Frame type", "v120.control.ftype", FT_UINT16, BASE_HEX,

        VALS(ftype_vals), XDLC_S_U_MASK, NULL, HFILL }},

    { &hf_v120_header8,

      { "Header", "v120.header", FT_UINT8, BASE_HEX, NULL, 0x0,

        NULL, HFILL }},

    { &hf_v120_header_ext8,

      { "Extension octet", "v120.header.ext", FT_BOOLEAN, 8, TFS(&tfs_yes_no), 0x80,

        NULL, HFILL }},

    { &hf_v120_header_break8,

      { "Break condition", "v120.header.break", FT_BOOLEAN, 8, TFS(&tfs_yes_no), 0x40,

        NULL, HFILL }},

    { &hf_v120_header_error_control8,

      { "Error control C1/C2", "v120.error_control", FT_UINT8, BASE_HEX, NULL, 0x0C,

        NULL, HFILL }},

    { &hf_v120_header_segb8,

      { "Bit B", "v120.header.segb", FT_BOOLEAN, 8, TFS(&tfs_segmentation_no_segmentation), 0x02,

        NULL, HFILL }},

    { &hf_v120_header_segf8,

      { "Bit F", "v120.header.segf", FT_BOOLEAN, 8, TFS(&tfs_segmentation_no_segmentation), 0x01,

        NULL, HFILL }},

    { &hf_v120_header16,

      { "Header", "v120.header", FT_UINT16, BASE_HEX, NULL, 0x0,

        NULL, HFILL }},

    { &hf_v120_header_ext16,

      { "Extension octet", "v120.header.ext", FT_BOOLEAN, 16, TFS(&tfs_yes_no), 0x0080,

        NULL, HFILL }},

    { &hf_v120_header_break16,

      { "Break condition", "v120.header.break", FT_BOOLEAN, 16, TFS(&tfs_yes_no), 0x0040,

        NULL, HFILL }},

    { &hf_v120_header_error_control16,

      { "Error control C1/C2", "v120.error_control", FT_UINT16, BASE_HEX, NULL, 0x0C,

        NULL, HFILL }},

    { &hf_v120_header_segb16,

      { "Bit B", "v120.header.segb", FT_BOOLEAN, 16, TFS(&tfs_segmentation_no_segmentation), 0x0002,

        NULL, HFILL }},

    { &hf_v120_header_segf16,

      { "Bit F", "v120.header.segf", FT_BOOLEAN, 16, TFS(&tfs_segmentation_no_segmentation), 0x0001,

        NULL, HFILL }},

    { &hf_v120_header_e,

      { "E", "v120.header.e", FT_BOOLEAN, 16, TFS(&tfs_yes_no), 0x8000,

        NULL, HFILL }},

    { &hf_v120_header_dr,

      { "DR", "v120.header.dr", FT_BOOLEAN, 16, TFS(&tfs_yes_no), 0x4000,

        NULL, HFILL }},

    { &hf_v120_header_sr,

      { "SR", "v120.header.sr", FT_BOOLEAN, 16, TFS(&tfs_yes_no), 0x2000,

        NULL, HFILL }},

    { &hf_v120_header_rr,

      { "RR", "v120.header.rr", FT_BOOLEAN, 16, TFS(&tfs_yes_no), 0x1000,

        NULL, HFILL }},

  };

  static int *ett[] = {

    &ett_v120,

    &ett_v120_address,

    &ett_v120_control,

    &ett_v120_header,

  };

  proto_v120 = proto_register_protocol("Async data over ISDN (V.120)",

               "V.120", "v120");

  proto_register_field_array (proto_v120, hf, array_length(hf));

  proto_register_subtree_array(ett, array_length(ett));

  register_dissector("v120", dissect_v120, proto_v120);

}

/*

 * Editor modelines  -  https://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:

 */