/* packet-canopen.c
 * Routines for CANopen dissection
 * Copyright 2011, Yegor Yefremov <yegorslists@googlemail.com>
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"

#include <glib.h>

#include <epan/packet.h>

void proto_register_canopen(void);

/* Initialize the protocol and registered fields */
static int proto_canopen = -1;
static int hf_canopen_cob_id = -1;
static int hf_canopen_function_code = -1;
static int hf_canopen_node_id = -1;
static int hf_canopen_pdo_data = -1;
static int hf_canopen_pdo_data_string = -1;
static int hf_canopen_sdo_cmd = -1;
static int hf_canopen_sdo_main_idx = -1;
static int hf_canopen_sdo_sub_idx = -1;
static int hf_canopen_sdo_data = -1;
static int hf_canopen_em_err_code = -1;
static int hf_canopen_em_err_reg = -1;
static int hf_canopen_em_err_field = -1;
static int hf_canopen_nmt_ctrl_cs = -1;
static int hf_canopen_nmt_ctrl_node_id = -1;
static int hf_canopen_nmt_guard_state = -1;
static int hf_canopen_time_stamp = -1;
static int hf_canopen_time_stamp_ms = -1;
static int hf_canopen_time_stamp_days = -1;

/* Initialize the subtree pointers */
static gint ett_canopen = -1;

/* broadcast messages */
#define FC_NMT                  0x0
#define FC_SYNC                 0x1
#define FC_TIME_STAMP           0x2

/* point-to-point messages */
#define FC_EMERGENCY            0x1
#define FC_PDO1_TX              0x3
#define FC_PDO1_RX              0x4
#define FC_PDO2_TX              0x5
#define FC_PDO2_RX              0x6
#define FC_PDO3_TX              0x7
#define FC_PDO3_RX              0x8
#define FC_PDO4_TX              0x9
#define FC_PDO4_RX              0xA
#define FC_DEFAULT_SDO_TX       0xB
#define FC_DEFAULT_SDO_RX       0xC
#define FC_NMT_ERR_CONTROL      0xE

static const value_string CAN_open_bcast_msg_type_vals[] = {
    { FC_NMT,              "EMERGENCY"},
    { FC_SYNC,             "Sync"},
    { FC_TIME_STAMP,       "TIME STAMP"},
    { 0, NULL}
};

static const value_string CAN_open_p2p_msg_type_vals[] = {
    { FC_EMERGENCY,        "EMERGENCY"},
    { FC_PDO1_TX,          "PDO1 (tx)"},
    { FC_PDO1_RX,          "PDO1 (rx)"},
    { FC_PDO2_TX,          "PDO2 (tx)"},
    { FC_PDO2_RX,          "PDO2 (rx)"},
    { FC_PDO3_TX,          "PDO3 (tx)"},
    { FC_PDO3_RX,          "PDO3 (rx)"},
    { FC_PDO4_TX,          "PDO4 (tx)"},
    { FC_PDO4_RX,          "PDO4 (rx)"},
    { FC_DEFAULT_SDO_TX,   "Default-SDO (tx)"},
    { FC_DEFAULT_SDO_RX,   "Default-SDO (rx)"},
    { FC_NMT_ERR_CONTROL,  "NMT Error Control"},
    { 0, NULL}
};

/* message types */
#define MT_UNKNOWN                       0
#define MT_NMT_CTRL                      1
#define MT_SYNC                          2
#define MT_TIME_STAMP                    3
#define MT_EMERGENCY                     4
#define MT_PDO                           5
#define MT_SDO                           6
#define MT_NMT_GUARD                     7

/* TIME STAMP conversion defines */
#define TS_DAYS_BETWEEN_1970_AND_1984   5113
#define TS_SECONDS_IN_PER_DAY           86400
#define TS_NANOSEC_PER_MSEC             1000000

/* NMT command specifiers */
static const value_string nmt_ctrl_cs[] = {
    { 0x01, "Start remote node"},
    { 0x02, "Stop remote node"},
    { 0x80, "Enter pre-operational state"},
    { 0x81, "Reset node"},
    { 0x82, "Reset communication"},
    { 0, NULL}
};

/* NMT states */
static const value_string nmt_guard_state[] = {
    { 0x00, "Initialising"},
    { 0x01, "Disconnected"},
    { 0x02, "Connecting"},
    { 0x03, "Preparing"},
    { 0x04, "Stopped"},
    { 0x05, "Operational"},
    { 0x7F, "Pre-operational"},
    { 0, NULL}
};

static guint
canopen_detect_msg_type(guint function_code, guint node_id)
{
    switch (function_code) {
        case FC_NMT:
            return MT_NMT_CTRL;
            break;
        case FC_SYNC:
            if (node_id == 0) {
                return MT_SYNC;
            } else {
                return MT_EMERGENCY;
            }
            break;
        case FC_TIME_STAMP:
            return MT_TIME_STAMP;
            break;
        case FC_PDO1_TX:
            return MT_PDO;
            break;
        case FC_PDO1_RX:
            return MT_PDO;
            break;
        case FC_PDO2_TX:
            return MT_PDO;
            break;
        case FC_PDO2_RX:
            return MT_PDO;
            break;
        case FC_PDO3_TX:
            return MT_PDO;
            break;
        case FC_PDO3_RX:
            return MT_PDO;
            break;
        case FC_PDO4_TX:
            return MT_PDO;
            break;
        case FC_PDO4_RX:
            return MT_PDO;
            break;
        case FC_DEFAULT_SDO_TX:
            return MT_SDO;
            break;
        case FC_DEFAULT_SDO_RX:
            return MT_SDO;
            break;
        case FC_NMT_ERR_CONTROL:
            return MT_NMT_GUARD;
            break;
        default:
            return MT_UNKNOWN;
            break;
    }
}

struct can_identifier
{
    guint32 id;
};

/* Code to actually dissect the packets */
static int
dissect_canopen(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
{
    guint        function_code;
    guint        node_id;
    guint32      time_stamp_msec;
    guint32      time_stamp_days;
    struct can_identifier can_id;
    guint        msg_type_id;
    nstime_t     time_stamp;
    gint         can_data_len = tvb_reported_length(tvb);
    const gchar *function_code_str;
    int offset = 0;

    DISSECTOR_ASSERT(data);
    can_id = *((struct can_identifier*)data);

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "CANopen");
    col_clear(pinfo->cinfo, COL_INFO);

    node_id       = can_id.id & 0x7F;
    function_code = (can_id.id >> 7) & 0x0F;

    msg_type_id = canopen_detect_msg_type(function_code, node_id);

    if (node_id == 0 ) {
        /* broadcast */
        function_code_str = val_to_str(function_code, CAN_open_bcast_msg_type_vals, "Unknown (%u)");
        col_add_fstr(pinfo->cinfo, COL_INFO, "%s", function_code_str);
    } else {
        /* point-to-point */
        function_code_str = val_to_str(function_code, CAN_open_p2p_msg_type_vals, "Unknown (%u)");
        col_add_fstr(pinfo->cinfo, COL_INFO, "p2p %s", function_code_str);
    }
    col_append_fstr(pinfo->cinfo, COL_INFO, "   %s",
                    tvb_bytes_to_ep_str_punct(tvb, offset, can_data_len, ' '));

    if (tree) {
        proto_item *ti, *cob_ti, *type_ti;
        proto_tree *canopen_tree;
        proto_tree *canopen_cob_tree;
        proto_tree *canopen_type_tree;

        ti = proto_tree_add_item(tree, proto_canopen, tvb, 0, tvb_reported_length(tvb), ENC_NA);
        canopen_tree = proto_item_add_subtree(ti, ett_canopen);

        /* add COB-ID with function code and node id */
        cob_ti = proto_tree_add_uint(canopen_tree, hf_canopen_cob_id, tvb, 0, 0, can_id.id);
        canopen_cob_tree = proto_item_add_subtree(cob_ti, ett_canopen);

        /* add function code */
        ti = proto_tree_add_uint(canopen_cob_tree, hf_canopen_function_code, tvb, 0, 0, can_id.id);
        PROTO_ITEM_SET_GENERATED(ti);

        /* add node id */
        ti = proto_tree_add_uint(canopen_cob_tree, hf_canopen_node_id, tvb, 0, 0, can_id.id);
        PROTO_ITEM_SET_GENERATED(ti);

        /* add CANopen frame type */

        type_ti = proto_tree_add_text(canopen_tree, tvb, 0, tvb_reported_length(tvb),
                                      "Type: %s", function_code_str);
        canopen_type_tree = proto_item_add_subtree(type_ti, ett_canopen);

        switch(msg_type_id)
        {
        case MT_NMT_CTRL:
            proto_tree_add_item(canopen_type_tree,
                hf_canopen_nmt_ctrl_cs, tvb, offset, 1, ENC_BIG_ENDIAN);
            offset++;

            proto_tree_add_item(canopen_type_tree,
                hf_canopen_nmt_ctrl_node_id, tvb, offset, 1, ENC_BIG_ENDIAN);
            break;
        case MT_NMT_GUARD:
            proto_tree_add_item(canopen_type_tree,
                hf_canopen_nmt_guard_state, tvb, offset, 1, ENC_BIG_ENDIAN);
            break;
        case MT_SYNC:
            break;
        case MT_TIME_STAMP:
            /* calculate the real time stamp */
            time_stamp_msec = tvb_get_letohl(tvb, offset);
            time_stamp_days = tvb_get_ntohs(tvb, offset + 4);
            time_stamp.secs = (time_stamp_days + TS_DAYS_BETWEEN_1970_AND_1984)
                * TS_SECONDS_IN_PER_DAY + (time_stamp_msec / 1000);
            time_stamp.nsecs = (time_stamp_msec % 1000) * TS_NANOSEC_PER_MSEC;

            proto_tree_add_time(canopen_type_tree,
                hf_canopen_time_stamp, tvb, offset, 6, &time_stamp);

            proto_tree_add_uint(canopen_type_tree,
                hf_canopen_time_stamp_ms, tvb, offset, 4, time_stamp_msec);
            offset += 2;

            proto_tree_add_uint(canopen_type_tree,
                hf_canopen_time_stamp_days, tvb, offset, 2, time_stamp_days);

            break;
        case MT_EMERGENCY:
            proto_tree_add_item(canopen_type_tree,
                hf_canopen_em_err_code, tvb, offset, 2, ENC_BIG_ENDIAN);
            offset += 2;

            proto_tree_add_item(canopen_type_tree,
                hf_canopen_em_err_reg, tvb, offset, 1, ENC_BIG_ENDIAN);
            offset++;

            proto_tree_add_item(canopen_type_tree,
                hf_canopen_em_err_field, tvb, offset, 4, ENC_NA);
            break;
        case MT_PDO:
            if (can_data_len != 0) {
                proto_tree_add_item(canopen_type_tree,
                    hf_canopen_pdo_data, tvb, offset, can_data_len, ENC_NA);
            }
            else {
                proto_tree_add_string(canopen_type_tree,
                    hf_canopen_pdo_data_string, tvb, offset, 0, "empty");
            }
            break;
        case MT_SDO:
            proto_tree_add_item(canopen_type_tree,
                hf_canopen_sdo_cmd, tvb, offset, 1, ENC_BIG_ENDIAN);
            offset++;

            proto_tree_add_item(canopen_type_tree,
                hf_canopen_sdo_main_idx, tvb, offset, 2, ENC_BIG_ENDIAN);
            offset += 2;

            proto_tree_add_item(canopen_type_tree,
                hf_canopen_sdo_sub_idx, tvb, offset, 1, ENC_BIG_ENDIAN);
            offset++;

            proto_tree_add_item(canopen_type_tree,
                hf_canopen_sdo_data, tvb, offset, 4, ENC_NA);
            break;
        }
    }

    return tvb_length(tvb);
}


/* Register the protocol with Wireshark */
void
proto_register_canopen(void)
{
    static hf_register_info hf[] = {
        { &hf_canopen_cob_id,
          { "COB-ID",           "canopen.cob_id",
            FT_UINT32, BASE_HEX, NULL, 0x0,
            NULL, HFILL }
        },
        { &hf_canopen_function_code,
          { "Function code", "canopen.function_code",
            FT_UINT32, BASE_HEX, NULL, 0x780,
            NULL, HFILL }
        },
        { &hf_canopen_node_id,
          { "Node-ID", "canopen.node_id",
            FT_UINT32, BASE_HEX, NULL, 0x7F,
            NULL, HFILL }
        },
        { &hf_canopen_pdo_data,
          { "Data", "canopen.pdo.data",
            FT_BYTES, BASE_NONE, NULL, 0x0,
            NULL, HFILL }
        },
        { &hf_canopen_pdo_data_string,
          { "Data", "canopen.pdo.data",
            FT_STRINGZ, BASE_NONE, NULL, 0x0,
            NULL, HFILL }
        },
        { &hf_canopen_sdo_cmd,
          { "SDO command byte", "canopen.sdo.cmd",
            FT_UINT8, BASE_HEX, NULL, 0x0,
            NULL, HFILL }
        },
        { &hf_canopen_sdo_main_idx,
          { "OD main-index", "canopen.sdo.main_idx",
            FT_UINT16, BASE_HEX, NULL, 0x0,
            NULL, HFILL }
        },
        { &hf_canopen_sdo_sub_idx,
          { "OD sub-index", "canopen.sdo.sub_idx",
            FT_UINT8, BASE_HEX, NULL, 0x0,
            NULL, HFILL }
        },
        { &hf_canopen_sdo_data,
          { "Data", "canopen.sdo.data",
            FT_BYTES, BASE_NONE, NULL, 0x0,
            NULL, HFILL }
        },
        { &hf_canopen_em_err_code,
          { "Error code", "canopen.em.err_code",
            FT_UINT16, BASE_HEX, NULL, 0x0,
            NULL, HFILL }
        },
        { &hf_canopen_em_err_reg,
          { "Error register", "canopen.em.err_reg",
            FT_UINT8, BASE_HEX, NULL, 0x0,
            NULL, HFILL }
        },
        { &hf_canopen_em_err_field,
          { "Manufacture specific error field", "canopen.em.err_field",
            FT_BYTES, BASE_NONE, NULL, 0x0,
            NULL, HFILL }
        },
        { &hf_canopen_nmt_ctrl_cs,
          { "Command specifier", "canopen.nmt_ctrl.cd",
            FT_UINT8, BASE_HEX, VALS(nmt_ctrl_cs), 0xFF,
            NULL, HFILL }
        },
        { &hf_canopen_nmt_ctrl_node_id,
          { "Node-ID", "canopen.nmt_ctrl.node_id",
            FT_UINT8, BASE_HEX, NULL, 0x0,
            NULL, HFILL }
        },
        { &hf_canopen_nmt_guard_state,
          { "Node-ID", "canopen.nmt_guard.state",
            FT_UINT8, BASE_HEX, VALS(nmt_guard_state), 0x7F,
            NULL, HFILL }
        },
        { &hf_canopen_time_stamp,
          { "Time stamp",           "canopen.time_stamp",
            FT_ABSOLUTE_TIME, ABSOLUTE_TIME_UTC, NULL, 0x0,
            NULL, HFILL }
        },
        { &hf_canopen_time_stamp_ms,
          { "Time, after Midnight in Milliseconds", "canopen.time_stamp_ms",
            FT_UINT32, BASE_DEC, NULL, 0x0,
            NULL, HFILL }
        },
        { &hf_canopen_time_stamp_days,
          { "Current day since 1 Jan 1984", "canopen.time_stamp_days",
            FT_UINT16, BASE_DEC, NULL, 0x0,
            NULL, HFILL }
        },
    };

    static gint *ett[] = {
        &ett_canopen
    };

    proto_canopen = proto_register_protocol("CANopen",
                                            "CANOPEN",
                                            "canopen");

    new_register_dissector("canopen", dissect_canopen, proto_canopen);

    proto_register_field_array(proto_canopen, hf, array_length(hf));
    proto_register_subtree_array(ett, array_length(ett));
}

