/* packet-ipars.c

 * Routines for IPARS/ALC (International Passenger Airline Reservation System/Airline Link Control) WAN protocol dissection

 * Copyright 2007, Fulko Hew, SITA INC Canada, Inc.

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

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

 */

/* NOTE:    This should be rewritten to be more in line with how packet-uts.c is

 *          written so that there are filterable fields available for IPARS too.

 */

#include "config.h"

#include <epan/packet.h>

#include <wsutil/str_util.h>

void proto_register_ipars(void);

static int      proto_ipars;

static int      ett_ipars;

#define S1      (0x00)

#define S2      (0x20)

#define GA      (0x03)

#define EOMpb   (0x10)

#define EOMc    (0x11)

#define EOMu    (0x12)

#define EOMi    (0x13)

#define MAX_EOM_MSG_SIZE    (24)            /* max size of an EOMx indicator string */

static int

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

{

    int       bytes;

    uint8_t   ia     = 0, ta = 0, cmd = 0, la = 0;

    tvbuff_t *next_tvb;

    int       offset = 0;

    char     *eom_msg;

    uint8_t   ipars_eomtype;

    eom_msg    = (char *)wmem_alloc(pinfo->pool, MAX_EOM_MSG_SIZE);

    eom_msg[0] = 0;

    col_clear(pinfo->cinfo, COL_INFO);

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "IPARS");

    if (tvb_captured_length_remaining(tvb, 0) >= 2 ) {

        ia = tvb_get_uint8(tvb, 0) & 0x3f;

        ta = tvb_get_uint8(tvb, 1) & 0x3f;

        if (ia == S1 && ta == S2) { /* if the first two bytes are S1/S2 skip over them */

            offset = 2;

        }

    }

    if (tvb_captured_length_remaining(tvb, offset) >= 1) ia = tvb_get_uint8(tvb, offset + 0);

    if (tvb_captured_length_remaining(tvb, offset) >= 2) ta = tvb_get_uint8(tvb, offset + 1);

    if (ia == 0x83 || ia == 0x43 || ia == GA) { /* if it's an FPGA or 'corresponsdance code' 'go ahead'... */

        if (tvb_captured_length_remaining(tvb, offset) > 2) { /* if the msg is long, it must have been a 'poll' */

            col_add_fstr(pinfo->cinfo, COL_INFO, "Poll IA: %2.2X", ta);

        } else { /* if it's short, then it was a 'no traffic' response */

            if (tvb_captured_length_remaining(tvb, offset) >= 2 ) {

                col_add_fstr(pinfo->cinfo, COL_INFO, "GoAhead NextIA (0x%2.2X)", ta);

            } else {

                col_set_str(pinfo->cinfo, COL_INFO, "GoAhead NextIA");

            }

        }

    } else { /* if it's not a 'go ahead'... it must be some kind of data message */

        ia &= 0x3f;

        ta &= 0x3f;

        if (ta == 0x20) {

            col_add_fstr(pinfo->cinfo, COL_INFO, "Reset IA: %2.2X", ia); /* the TA character was the 'reset' command */

        }

        if (tvb_captured_length_remaining(tvb, offset) >= 3) cmd = tvb_get_uint8(tvb, offset + 2) & 0x3f;   /* get the first two bytes of the data message */

        if (tvb_captured_length_remaining(tvb, offset) >= 4) la  = tvb_get_uint8(tvb, offset + 3) & 0x3f;

        if (cmd == 0x1f && la == 0x38) {

            col_add_fstr(pinfo->cinfo, COL_INFO, "Please Resend - IA: %2.2X TA: %2.2X", ia, ta); /* light the resend indicator */

        } else if (cmd == 0x2a && la == 0x05) {

            col_add_fstr(pinfo->cinfo, COL_INFO, "Unsolicited Msg Indicator - IA: %2.2X TA: %2.2X", ia, ta);    /* light the unsolicited msg indicator */

        } else {

            col_add_fstr(pinfo->cinfo, COL_INFO, "Data Msg - IA: %2.2X TA: %2.2X", ia, ta); /* it was a data message (display or printer */

        }

    }

    bytes = tvb_captured_length_remaining(tvb, 0);

    if (bytes > 0) {

        proto_tree  *ipars_tree;

        proto_item  *ti;

        ia = tvb_get_uint8(tvb, 0) & 0x3f;

        ti = proto_tree_add_protocol_format(tree, proto_ipars, tvb, 0, -1, "Ipars");

        ipars_tree = proto_item_add_subtree(ti, ett_ipars);

        if (ia == 0x03) {

            proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 0, 1, "GoAhead Next IA");

            col_set_str(pinfo->cinfo, COL_INFO, "GoAhead");

            return tvb_captured_length(tvb);

        } else if (ia != S1) {

            proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb,

                0,

                bytes, "Unknown format - Data (%d byte%s)", bytes,

                plurality(bytes, "", "s"));

            return tvb_captured_length(tvb);

        }

        proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 0, 1, "S1");

        ia = tvb_get_uint8(tvb, 1) & 0x3f;

        if (ia != S2) {

            proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb,

                0,

                bytes, "Unknown format - Data (%d byte%s)", bytes,

                plurality(bytes, "", "s"));

                return tvb_captured_length(tvb);

        }

        proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 1, 1, "S2");

        ia = tvb_get_uint8(tvb, 2) & 0x3f;

        if (ia == GA) {

            ia = tvb_get_uint8(tvb, 3) & 0x3f;

            proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 2, 2, "GoAhead IA: %2.2X", ia);

            ipars_eomtype = tvb_get_uint8(tvb, 4) & 0x3f;

            switch (ipars_eomtype) {

                case EOMc:  snprintf(eom_msg, MAX_EOM_MSG_SIZE, "EOMc");                              break;

                case EOMi:  snprintf(eom_msg, MAX_EOM_MSG_SIZE, "EOMi");                              break;

                case EOMu:  snprintf(eom_msg, MAX_EOM_MSG_SIZE, "EOMu");                              break;

                case EOMpb: snprintf(eom_msg, MAX_EOM_MSG_SIZE, "EOMpb");                             break;

                default:    snprintf(eom_msg, MAX_EOM_MSG_SIZE, "Unknown EOM type (0x%2.2X)", ipars_eomtype);    break;

            }

            proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 4, 1, "%s", eom_msg);

            proto_tree_add_protocol_format(ipars_tree, proto_ipars, tvb, 5, 1, "Good BCC");

        } else {

            next_tvb = tvb_new_subset_remaining(tvb, 3);

            bytes = tvb_captured_length(next_tvb);

            proto_tree_add_protocol_format(ipars_tree, proto_ipars, next_tvb,

                0,

                bytes, "Data (%d byte%s)", bytes,

                plurality(bytes, "", "s"));

            return tvb_captured_length(tvb);

        }

    }

    return tvb_captured_length(tvb);

}

void

proto_register_ipars(void)

{

    static int *ett[] = {

        &ett_ipars,

    };

    proto_ipars = proto_register_protocol("International Passenger Airline Reservation System", "IPARS", "ipars");

    proto_register_subtree_array(ett, array_length(ett));

    register_dissector("ipars", dissect_ipars, proto_ipars);

}

/*

 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html

 *

 * Local variables:

 * c-basic-offset: 4

 * tab-width: 8

 * indent-tabs-mode: nil

 * End:

 *

 * vi: set shiftwidth=4 tabstop=8 expandtab:

 * :indentSize=4:tabSize=8:noTabs=true:

 */