path: root/epan/dissectors/packet-bluecom.c

/* packet-bluecom.c
 *
 * Routines and register functions of bluecom dissector
 *
 * Bachmann bluecom Protocol
 * Packet dissector based on Ethernet
 *
 * COPYRIGHT BY BACHMANN ELECTRONIC GmbH 2016
 * Contact: Gerhard Khueny <g.khueny@bachmann.info>
 *
 * 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 <epan/packet.h>
#include <epan/etypes.h>
#include <epan/to_str.h>

/* bluecom protocol defines */

/* BCP_ETH_VLAN_HDR */
#define BCP_VLAN_TYPE        0x8100     /* ethernet vlan type */
#define BCP_ETH_TYPE         0x892D     /* ethernet type */

#define BCP_PROT_FLG_REQ     0x01       /* request */
#define BCP_PROT_FLG_RSP     0x02       /* response */
#define BCP_PROT_FLG_PRIM    0x80       /* primary */

/* BCP_BLOCK_HDR */
#define BCP_SLAVEID_ANY      0x0000     /* zero reserved */
#define BCP_SLAVEID_MASK     0x01FF     /* open range for 512 nodes */
                                        /* see 'BCP_MAX_NODE_NB' */
#define BCP_SLAVEID_MST      0x1000     /* master bit */
#define BCP_SLAVEID_SLV      0x2000     /* slave bit */

#define BCP_BLK_CMD_SYNC     0          /* master -> slave */
#define BCP_BLK_CMD_DATA     1          /* master/slave -> slave/master */
#define BCP_BLK_CMD_IDENTIFY 2          /* slave -> master */
#define BCP_BLK_CMD_SEARCH   3          /* master/slave -> slave */
#define BCP_BLK_CMD_CONNECT  4          /* master -> slave */

#define BCP_BLK_FLG_VALID    0x01       /* data written by APP -> valid */
#define BCP_BLK_FLG_PTP      0x02       /* PTP timestamp */

/* BCP_SEARCH_XXX */
#define BCP_NAME_LEN         32         /* slave name length */

#define BCP_SEARCH_NAME      1          /* search options */
#define BCP_SEARCH_IPADDR    2
#define BCP_SEARCH_DEFAULT   BCP_SEARCH_NAME

#define BCP_ETHADDR_LEN      6          /* ethernet address length */

#define BCP_PROTOCOL_HDR_LEN    10 /* FIXME: use sizeof with packed from header */
#define BCP_BLOCK_HDR_LEN       24

/* helper defines */
#define BOOLSTR(val) ((val) ? "True" : "False")
#define REQRSP(val)  ((val & BCP_PROT_FLG_REQ) ? "Request " : "Response ")

/* prototypes */
void proto_reg_handoff_bluecom(void);
void proto_register_bluecom(void);

/* static handles */
static dissector_handle_t bcp_handle;
static dissector_table_t bcp_subdissector_table;

static gint proto_bcp = -1;
static gint ett_bcp = -1;
static gint ett_bcp_header = -1;
static gint ett_bcp_blockheader = -1;
static gint ett_bcp_data = -1;

/* protocol data id */
static gint hf_bcp_hdr_version = -1;
static gint hf_bcp_hdr_format = -1;
static gint hf_bcp_hdr_protflags = -1;
static gint hf_bcp_hdr_blocknb = -1;
static gint hf_bcp_hdr_segcode = -1;
static gint hf_bcp_hdr_auth = -1;
static gint hf_bcp_hdr_sourceid = -1;
static gint hf_bcp_hdr_destid = -1;
static gint hf_bcp_hdr_transid = -1;
static gint hf_bcp_hdr_cmd = -1;
static gint hf_bcp_hdr_slavestate = -1;
static gint hf_bcp_hdr_blockflags = -1;
static gint hf_bcp_hdr_len = -1;
static gint hf_bcp_hdr_timestamp = -1;
static gint hf_bcp_hdr_fragoffset = -1;

static gint hf_bcp_sync_starttime = -1;
static gint hf_bcp_sync_cycletime = -1;
static gint hf_bcp_sync_dataratio = -1;
static gint hf_bcp_sync_identify = -1;
static gint hf_bcp_sync_vlantag = -1;
static gint hf_bcp_sync_ethaddr = -1;
static gint hf_bcp_sync_ethaddr2 = -1;

static gint hf_bcp_identify_error = -1;
static gint hf_bcp_identify_starttime = -1;
static gint hf_bcp_identify_ipaddr = -1;
static gint hf_bcp_identify_name = -1;
static gint hf_bcp_identify_ethaddr = -1;
static gint hf_bcp_identify_ethaddr2 = -1;

static gint hf_bcp_searchreq_addrtype = -1;
static gint hf_bcp_searchreq_reserved = -1;
static gint hf_bcp_searchreq_name = -1;
static gint hf_bcp_searchreq_ipaddrfirst = -1;
static gint hf_bcp_searchreq_ipaddrlast = -1;
static gint hf_bcp_searchreq_addrdata = -1;

static gint hf_bcp_searchrsp_error = -1;
static gint hf_bcp_searchrsp_starttime = -1;
static gint hf_bcp_searchrsp_lenin = -1;
static gint hf_bcp_searchrsp_lenout = -1;
static gint hf_bcp_searchrsp_ipaddr = -1;
static gint hf_bcp_searchrsp_name = -1;
static gint hf_bcp_searchrsp_ethaddr = -1;
static gint hf_bcp_searchrsp_ethaddr2 = -1;

static gint hf_bcp_connectreq_lenin = -1;
static gint hf_bcp_connectreq_lenout = -1;
static gint hf_bcp_connectreq_cycletime = -1;
static gint hf_bcp_connectreq_offlinefactor = -1;
static gint hf_bcp_connectreq_ipaddr = -1;
static gint hf_bcp_connectreq_name = -1;
static gint hf_bcp_connectreq_ethaddr = -1;
static gint hf_bcp_connectreq_ethaddr2 = -1;

static gint hf_bcp_connectrsp_error = -1;
static gint hf_bcp_connectrsp_lenin = -1;
static gint hf_bcp_connectrsp_lenout = -1;

static gint hf_bcp_userdata = -1;

/* command defines */
static const value_string bcp_cmds[] = {
    { BCP_BLK_CMD_SYNC, "SYNC" },
    { BCP_BLK_CMD_DATA, "DATA" },
    { BCP_BLK_CMD_IDENTIFY, "IDENTIFY" },
    { BCP_BLK_CMD_SEARCH, "SEARCH" },
    { BCP_BLK_CMD_CONNECT, "CONNECT" },
    { 0, NULL }
};

/*
 * dissector function of connect data (request and response)
 *
 * input: tree, buffer (data), offset (data pointer), length of data, flags (req or rsp)
 * output: offset
 * return: nothing
 */
static void
dissect_bcp_connect_data(proto_tree *bcp_tree, tvbuff_t *tvb,
                        guint *offset, guint len, gint flags)
{
    proto_tree *bcp_subtree = NULL;
    guint offset_base = *offset;

    if (flags & BCP_PROT_FLG_REQ)
    {
        bcp_subtree = proto_tree_add_subtree_format(bcp_tree, tvb, *offset, len, ett_bcp_data, NULL,
                                                    "BCP Connect Request: Name=%s IpAddr=%s",
                                                    tvb_get_string_enc(wmem_packet_scope(), tvb, *offset + 16, BCP_NAME_LEN, ENC_ASCII),
                                                    tvb_ip_to_str(tvb, *offset + 12));

        proto_tree_add_item(bcp_subtree, hf_bcp_connectreq_lenin, tvb, *offset, 2, ENC_BIG_ENDIAN);
        *offset += 2;
        proto_tree_add_item(bcp_subtree, hf_bcp_connectreq_lenout, tvb, *offset, 2, ENC_BIG_ENDIAN);
        *offset += 2;
        proto_tree_add_item(bcp_subtree, hf_bcp_connectreq_cycletime, tvb, *offset, 4, ENC_BIG_ENDIAN);
        *offset += 4;
        proto_tree_add_item(bcp_subtree, hf_bcp_connectreq_offlinefactor, tvb, *offset, 2, ENC_BIG_ENDIAN);
        *offset += 4;
        proto_tree_add_item(bcp_subtree, hf_bcp_connectreq_ipaddr, tvb, *offset, 4, ENC_BIG_ENDIAN);
        *offset += 4;
        proto_tree_add_item(bcp_subtree, hf_bcp_connectreq_name, tvb, *offset, BCP_NAME_LEN, ENC_ASCII|ENC_NA);
        *offset += BCP_NAME_LEN;
        proto_tree_add_item(bcp_subtree, hf_bcp_connectreq_ethaddr, tvb, *offset, BCP_ETHADDR_LEN, ENC_NA);
        *offset += BCP_ETHADDR_LEN;
        if((len-(*offset-offset_base)))
        {
            proto_tree_add_item(bcp_subtree, hf_bcp_connectreq_ethaddr2, tvb, *offset, BCP_ETHADDR_LEN, ENC_NA);
            *offset += BCP_ETHADDR_LEN;
        }
    }

    if (flags & BCP_PROT_FLG_RSP)
    {
        bcp_subtree = proto_tree_add_subtree_format(bcp_tree, tvb, *offset, len, ett_bcp_data, NULL,
                                                    "BCP Connect Response: Error=%d",
                                                    tvb_get_ntohl(tvb, *offset));

        proto_tree_add_item(bcp_subtree, hf_bcp_connectrsp_error, tvb, *offset, 4, ENC_BIG_ENDIAN);
        *offset += 4;
        proto_tree_add_item(bcp_subtree, hf_bcp_connectrsp_lenin, tvb, *offset, 2, ENC_BIG_ENDIAN);
        *offset += 2;
        proto_tree_add_item(bcp_subtree, hf_bcp_connectrsp_lenout, tvb, *offset, 2, ENC_BIG_ENDIAN);
        *offset += 2;
    }

    *offset = offset_base + len;
}

/*
 * dissector function of search data (request and response)
 *
 * input: tree, buffer (data), offset (data pointer), length of data, flags (req or rsp)
 * output: offset
 * return: nothing
 */
static void
dissect_bcp_search_data(proto_tree *bcp_tree, tvbuff_t *tvb,
                       guint *offset, guint len, gint flags)
{
    proto_tree *bcp_subtree = NULL;
    guint type = 0;
    guint offset_base = *offset;

    if (flags & BCP_PROT_FLG_REQ)
    {
        type = tvb_get_ntohl(tvb, *offset);
        switch (type)
        {
            case BCP_SEARCH_IPADDR:
                bcp_subtree = proto_tree_add_subtree_format(bcp_tree, tvb, *offset, len, ett_bcp_data, NULL,
                                  "BCP Search Request: IpAddrFirst=%s, IpAddrLast=%s",
                                  tvb_ip_to_str(tvb, *offset + 8),
                                  tvb_ip_to_str(tvb, *offset + 12)
                                  );
                break;

            case BCP_SEARCH_NAME:
                bcp_subtree = proto_tree_add_subtree_format(bcp_tree, tvb, *offset, len, ett_bcp_data, NULL,
                                  "BCP Search Request: Name=%s",
                                  tvb_get_string_enc(wmem_packet_scope(), tvb, *offset + 8, BCP_NAME_LEN, ENC_ASCII)
                                  );
                break;

            default:
                bcp_subtree = proto_tree_add_subtree_format(bcp_tree, tvb, *offset, len, ett_bcp_data, NULL,
                                  "BCP Search Request: Unknown AddrType");
                break;
        }

        proto_tree_add_item(bcp_subtree, hf_bcp_searchreq_addrtype, tvb, *offset, 4, ENC_BIG_ENDIAN);
        *offset += 4;
        proto_tree_add_item(bcp_subtree, hf_bcp_searchreq_reserved, tvb, *offset, 4, ENC_BIG_ENDIAN);
        *offset += 4;

        switch (type)
        {
            case BCP_SEARCH_IPADDR:
                proto_tree_add_item(bcp_subtree, hf_bcp_searchreq_ipaddrfirst, tvb, *offset, 4, ENC_BIG_ENDIAN);
                proto_tree_add_item(bcp_subtree, hf_bcp_searchreq_ipaddrlast, tvb, *offset + 4, 4, ENC_BIG_ENDIAN);
                break;

            case BCP_SEARCH_NAME:
                proto_tree_add_item(bcp_subtree, hf_bcp_searchreq_name, tvb, *offset, BCP_NAME_LEN, ENC_ASCII|ENC_NA);
                break;

            default:
                proto_tree_add_bytes_format(bcp_subtree, hf_bcp_searchreq_addrdata, tvb, *offset, BCP_NAME_LEN,
                                            NULL, "Unknown Address Data (%u bytes)", BCP_NAME_LEN);
                break;
        }
        *offset += BCP_NAME_LEN;
    }

    if (flags & BCP_PROT_FLG_RSP)
    {
        bcp_subtree = proto_tree_add_subtree_format(bcp_tree, tvb, *offset, len, ett_bcp_data, NULL,
                          "BCP Search Response: Name=%s, IpAddr=%s Error=%d",
                          tvb_get_string_enc(wmem_packet_scope(), tvb, *offset + 16, BCP_NAME_LEN, ENC_ASCII),
                          tvb_ip_to_str(tvb, *offset + 12),
                          tvb_get_letohl(tvb, *offset)
                          );

        proto_tree_add_item(bcp_subtree, hf_bcp_searchrsp_error, tvb, *offset, 4, ENC_NA);
        *offset += 4;
        proto_tree_add_item(bcp_subtree, hf_bcp_searchrsp_starttime, tvb, *offset, 4, ENC_BIG_ENDIAN);
        *offset += 4;
        proto_tree_add_item(bcp_subtree, hf_bcp_searchrsp_lenin, tvb, *offset, 2, ENC_BIG_ENDIAN);
        *offset += 2;
        proto_tree_add_item(bcp_subtree, hf_bcp_searchrsp_lenout, tvb, *offset, 2, ENC_BIG_ENDIAN);
        *offset += 2;
        proto_tree_add_item(bcp_subtree, hf_bcp_searchrsp_ipaddr, tvb, *offset, 4, ENC_BIG_ENDIAN);
        *offset += 4;
        proto_tree_add_item(bcp_subtree, hf_bcp_searchrsp_name, tvb, *offset, BCP_NAME_LEN, ENC_ASCII|ENC_NA);
        *offset += BCP_NAME_LEN;
        proto_tree_add_item(bcp_subtree, hf_bcp_searchrsp_ethaddr, tvb, *offset, BCP_ETHADDR_LEN, ENC_NA);
        *offset += BCP_ETHADDR_LEN;
        if((len-(*offset-offset_base)))
        {
            proto_tree_add_item(bcp_subtree, hf_bcp_searchrsp_ethaddr2, tvb, *offset, BCP_ETHADDR_LEN, ENC_NA);
            *offset += BCP_ETHADDR_LEN;
        }
    }
    *offset = offset_base + len;
}

/*
 * dissector function of identify data (request)
 *
 * input: tree, buffer (data), offset (data pointer), length of data, flags (req or rsp)
 * output: offset
 * return: nothing
 */
static void
dissect_bcp_identify_data(proto_tree *bcp_tree, tvbuff_t *tvb,
                          guint *offset, guint len)
{
    proto_tree *bcp_subtree = NULL;
    guint offset_base = *offset;

    bcp_subtree = proto_tree_add_subtree_format(bcp_tree, tvb, *offset, len, ett_bcp_data, NULL,
                    "BCP Identify Request: Name=%s, IpAddr=%s",
                    tvb_get_string_enc(wmem_packet_scope(), tvb, *offset + 12, BCP_NAME_LEN, ENC_ASCII),
                    tvb_ip_to_str(tvb, *offset + 8)
                    );

    proto_tree_add_item(bcp_subtree, hf_bcp_identify_error, tvb, *offset, 4, ENC_BIG_ENDIAN);
    *offset += 4;
    proto_tree_add_item(bcp_subtree, hf_bcp_identify_starttime, tvb, *offset, 4, ENC_BIG_ENDIAN);
    *offset += 4;
    proto_tree_add_item(bcp_subtree, hf_bcp_identify_ipaddr, tvb, *offset, 4, ENC_BIG_ENDIAN);
    *offset += 4;
    proto_tree_add_item(bcp_subtree, hf_bcp_identify_name, tvb, *offset, BCP_NAME_LEN, ENC_ASCII|ENC_NA);
    *offset += BCP_NAME_LEN;
    proto_tree_add_item(bcp_subtree, hf_bcp_identify_ethaddr, tvb, *offset, BCP_ETHADDR_LEN, ENC_NA);
    *offset += BCP_ETHADDR_LEN;
    if((len-(*offset-offset_base)))
    {
        proto_tree_add_item(bcp_subtree, hf_bcp_identify_ethaddr2, tvb, *offset, BCP_ETHADDR_LEN, ENC_NA);
        *offset += BCP_ETHADDR_LEN;
    }

    *offset = offset_base + len;
}

/*
 * dissector function of sync data
 *
 * input: tree, buffer (data), offset (data pointer), length of data
 * output: offset
 * return: nothing
 */
static void
dissect_bcp_sync_data(proto_tree *bcp_tree, tvbuff_t *tvb,
                      guint *offset, guint len)
{
    proto_tree *bcp_subtree = NULL;
    guint offset_base = *offset;

    bcp_subtree = proto_tree_add_subtree_format(bcp_tree, tvb, *offset, len, ett_bcp_data, NULL,
                                             "BCP Sync Data: Identify=%s",
                                             BOOLSTR(tvb_get_guint8(tvb, *offset + 9)));
    proto_tree_add_item(bcp_subtree, hf_bcp_sync_starttime, tvb, *offset, 4, ENC_BIG_ENDIAN);
    *offset += 4;
    proto_tree_add_item(bcp_subtree, hf_bcp_sync_cycletime, tvb, *offset, 4, ENC_BIG_ENDIAN);
    *offset += 4;
    proto_tree_add_item(bcp_subtree, hf_bcp_sync_dataratio, tvb, *offset, 1, ENC_BIG_ENDIAN);
    *offset += 1;
    proto_tree_add_item(bcp_subtree, hf_bcp_sync_identify, tvb, *offset, 1, ENC_BIG_ENDIAN);
    *offset += 1;
    proto_tree_add_item(bcp_subtree, hf_bcp_sync_vlantag, tvb, *offset, 2, ENC_BIG_ENDIAN);
    *offset += 2;

    /* protocol expansion*/
    if((len-(*offset-offset_base)))
    {
        proto_tree_add_item(bcp_subtree, hf_bcp_sync_ethaddr, tvb, *offset, BCP_ETHADDR_LEN, ENC_NA);
        *offset += BCP_ETHADDR_LEN;
        proto_tree_add_item(bcp_subtree, hf_bcp_sync_ethaddr2, tvb, *offset, BCP_ETHADDR_LEN, ENC_NA);
        *offset += BCP_ETHADDR_LEN;
    }

    *offset = offset_base + len;
}

/*
 * dissector function of data command
 *
 * input: tree, buffer (data), offset (data pointer), length of data
 * output: offset
 * return: nothing
 */
static void
dissect_bcp_data(proto_tree *bcp_tree, packet_info *pinfo, tvbuff_t *tvb,
                 guint *offset, guint len, gint segcode)
{
    dissector_handle_t  handle;
    tvbuff_t    *next_tvb;

    /* Probably a sub-dissector exists for this type/version combination. */
    handle = dissector_get_uint_handle(bcp_subdissector_table, segcode);

    if (handle)
    {
        /* Generate a new tvb for the rest. */
        next_tvb = tvb_new_subset(tvb, *offset, len, len);

        /* Call the sub-dissector. */
        call_dissector(handle, next_tvb, pinfo, bcp_tree);
        *offset += len;
    }
    else
    {
        proto_tree_add_item(bcp_tree, hf_bcp_userdata, tvb, *offset, len, ENC_NA);
        *offset += len;
    }
}


/*
 * dissector function of block header
 *
 * input: tree, buffer (data), offset (data pointer), number of header block
 * output: offset, command from header, length of following data
 * return: nothing
 */
static void
dissect_bcp_block_header(proto_tree *bcp_tree, tvbuff_t *tvb, guint *offset,
                         gint blocknb, gint *cmd, guint *len)
{
    proto_tree *bcp_subtree = NULL;

    *cmd = tvb_get_guint8(tvb, *offset + 6);
    *len = tvb_get_ntohs(tvb, *offset + 12);

    bcp_subtree = proto_tree_add_subtree_format(bcp_tree, tvb, *offset, BCP_BLOCK_HDR_LEN, ett_bcp_blockheader, NULL,
               "BCP Block Header (%d): Cmd=%s (%d), Len=%d",
               blocknb,
               val_to_str(*cmd, bcp_cmds, "UNKNOWN"), *cmd,
               *len
               );

    proto_tree_add_item(bcp_subtree, hf_bcp_hdr_sourceid, tvb, *offset, 2, ENC_BIG_ENDIAN);
    *offset += 2;
    proto_tree_add_item(bcp_subtree, hf_bcp_hdr_destid, tvb, *offset, 2, ENC_BIG_ENDIAN);
    *offset += 2;
    proto_tree_add_item(bcp_subtree, hf_bcp_hdr_transid, tvb, *offset, 2, ENC_BIG_ENDIAN);
    *offset += 2;
    proto_tree_add_item(bcp_subtree, hf_bcp_hdr_cmd, tvb, *offset, 1, ENC_BIG_ENDIAN);
    *offset += 1;
    proto_tree_add_item(bcp_subtree, hf_bcp_hdr_slavestate, tvb, *offset, 1, ENC_BIG_ENDIAN);
    *offset += 1;
    proto_tree_add_item(bcp_subtree, hf_bcp_hdr_blockflags, tvb, *offset, 1, ENC_BIG_ENDIAN);
    *offset += 4;
    proto_tree_add_item(bcp_subtree, hf_bcp_hdr_len, tvb, *offset, 2, ENC_BIG_ENDIAN);
    *offset += 2;
    proto_tree_add_item(bcp_subtree, hf_bcp_hdr_fragoffset, tvb, *offset, 2, ENC_BIG_ENDIAN);
    *offset += 2;
    proto_tree_add_item(bcp_subtree, hf_bcp_hdr_timestamp, tvb, *offset, 8, ENC_BIG_ENDIAN);
    *offset += 8;
}

/*
 * dissector function of protocol header
 *
 * input: tree, buffer (data), offset (data pointer)
 * output: offset, flags from header
 * return: nothing
 */
static void
dissect_bcp_protocol_header(proto_tree *bcp_tree, tvbuff_t *tvb,
                            guint *offset, gint *flags, gint *blocknb, gint *segcode)
{
    proto_tree *bcp_subtree = NULL;

    *flags = tvb_get_guint8(tvb, *offset + 2);
    *blocknb = tvb_get_guint8(tvb, *offset + 3);
    *segcode = tvb_get_ntohs(tvb, *offset + 4);

    bcp_subtree = proto_tree_add_subtree_format(bcp_tree, tvb, 0, BCP_PROTOCOL_HDR_LEN, ett_bcp_header, NULL,
                                                "BCP Protocol Header: BlockNb=%d, SegCode=%d",
                                                tvb_get_guint8(tvb, *offset + 3),
                                                tvb_get_ntohs(tvb, *offset + 4));

    proto_tree_add_item(bcp_subtree, hf_bcp_hdr_version, tvb, *offset, 1, ENC_BIG_ENDIAN);
    *offset += 1;
    proto_tree_add_item(bcp_subtree, hf_bcp_hdr_format, tvb, *offset, 1, ENC_BIG_ENDIAN);
    *offset += 1;
    proto_tree_add_item(bcp_subtree, hf_bcp_hdr_protflags, tvb, *offset, 1, ENC_BIG_ENDIAN);
    *offset += 1;
    proto_tree_add_item(bcp_subtree, hf_bcp_hdr_blocknb, tvb, *offset, 1, ENC_BIG_ENDIAN);
    *offset += 1;
    proto_tree_add_item(bcp_subtree, hf_bcp_hdr_segcode, tvb, *offset, 2, ENC_BIG_ENDIAN);
    *offset += 2;
    proto_tree_add_item(bcp_subtree, hf_bcp_hdr_auth, tvb, *offset, 4, ENC_BIG_ENDIAN);
    *offset += 4;
}


/*
 * dissect_bcp - the bcp dissector function
 */
static int dissect_bluecom(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
    gint cmd, flags, blocknb, segcode=0;
    gint data_cnt = 0;
    guint len, rlen;
    guint offset = 0;
    proto_tree *bcp_tree = NULL;
    proto_item *bcp_item_base = NULL;

    /* set protocol name column */
    col_set_str(pinfo->cinfo, COL_PROTOCOL, "bluecom");
    /* clear out stuff in the info column */
    col_set_str(pinfo->cinfo, COL_INFO, "CMD: ");

    /* add base item */
    bcp_item_base = proto_tree_add_item(tree, proto_bcp, tvb, 0, -1, ENC_NA);
    /* add base tree */
    bcp_tree = proto_item_add_subtree(bcp_item_base, ett_bcp);

    /* BCP header  */
    dissect_bcp_protocol_header(bcp_tree, tvb, &offset, &flags, &blocknb, &segcode);
    /* BCP block header*/
    dissect_bcp_block_header(bcp_tree, tvb, &offset, data_cnt, &cmd, &len);

    /* set info column */
    col_append_fstr(pinfo->cinfo, COL_INFO, "%s (%d) segcode=%d blocks=%d",
                    val_to_str(cmd, bcp_cmds, "UNKNOWN"), cmd, segcode, blocknb);

    /* append text to BCP base */
    proto_item_append_text(bcp_item_base, ", %s (%d) len=%d",
                           val_to_str(cmd, bcp_cmds, "UNKNOWN"), cmd, tvb_reported_length(tvb));

    switch (cmd) {
        case BCP_BLK_CMD_SYNC:
            dissect_bcp_sync_data(bcp_tree, tvb, &offset, len);
            break;

        case BCP_BLK_CMD_IDENTIFY:
            dissect_bcp_identify_data(bcp_tree, tvb, &offset, len);
            rlen = tvb_captured_length_remaining(tvb, offset);

            /* ignore additional bytes if < block header. Could be padding or cut of recording */
            while (rlen >= BCP_BLOCK_HDR_LEN)
            {
                /* BCP block header*/
                dissect_bcp_block_header(bcp_tree, tvb, &offset, ++data_cnt, &cmd, &len);
                rlen = tvb_captured_length_remaining(tvb, offset);
                /* calculate remaining data length */
                if (len > rlen)
                {
                    len = rlen;
                    col_append_fstr(pinfo->cinfo, COL_INFO, " [data len of block %d limited to %d]",
                                    data_cnt, len);
                    break;
                }
                dissect_bcp_identify_data(bcp_tree, tvb, &offset, len);
                rlen = tvb_captured_length_remaining(tvb, offset);
            }
            offset += rlen;
            break;

        case BCP_BLK_CMD_SEARCH:
            col_append_str(pinfo->cinfo, COL_INFO, REQRSP(flags));
            dissect_bcp_search_data(bcp_tree, tvb, &offset, len, flags);
            rlen = tvb_captured_length_remaining(tvb, offset);

            /* ignore additional bytes if < block header. Could be padding or cut of recording */
            while (rlen >= BCP_BLOCK_HDR_LEN)
            {
                /* BCP block header*/
                dissect_bcp_block_header(bcp_tree, tvb, &offset, ++data_cnt, &cmd, &len);
                rlen = tvb_captured_length_remaining(tvb, offset);
                /* calculate remaining data length */
                if (len > rlen)
                {
                    len = rlen;
                    col_append_fstr(pinfo->cinfo, COL_INFO, " [data len of block %d limited to %d]",
                                    data_cnt, len);
                    break;
                }
                dissect_bcp_search_data(bcp_tree, tvb, &offset, len, flags);
                rlen = tvb_captured_length_remaining(tvb, offset);
            }
            offset += rlen;
            break;

        case BCP_BLK_CMD_CONNECT:
            col_append_str(pinfo->cinfo, COL_INFO, REQRSP(flags));
            dissect_bcp_connect_data(bcp_tree, tvb, &offset, len, flags);
            rlen = tvb_captured_length_remaining(tvb, offset);

            /* ignore additional bytes if < block header. Could be padding or cut of recording */
            while (rlen >= BCP_BLOCK_HDR_LEN)
            {
                /* BCP block header*/
                dissect_bcp_block_header(bcp_tree, tvb, &offset, ++data_cnt, &cmd, &len);
                rlen = tvb_captured_length_remaining(tvb, offset);
                /* calculate remaining data length */
                if (len > rlen)
                {
                    len = rlen;
                    col_append_fstr(pinfo->cinfo, COL_INFO, " [data len of block %d limited to %d]",
                                    data_cnt, len);
                    break;
                }
                dissect_bcp_connect_data(bcp_tree, tvb, &offset, len, flags);
                rlen = tvb_captured_length_remaining(tvb, offset);
            }
            offset += rlen;
            break;

        case BCP_BLK_CMD_DATA:
        default:
            /* check if data packet was limited */
            rlen = tvb_captured_length_remaining(tvb, offset);
            if (len > rlen)
            {
                len = rlen;
                col_append_fstr(pinfo->cinfo, COL_INFO, " [data len of block %d limited to %d]",
                                data_cnt, len);
            }
            dissect_bcp_data(bcp_tree, pinfo, tvb, &offset, len, segcode);
            rlen = tvb_captured_length_remaining(tvb, offset);

            /* ignore additional bytes if < block header. Could be padding or cut of recording */
            while (rlen >= BCP_BLOCK_HDR_LEN)
            {
                /* BCP block header*/
                dissect_bcp_block_header(bcp_tree, tvb, &offset, ++data_cnt, &cmd, &len);
                rlen = tvb_captured_length_remaining(tvb, offset);
                /* calculate remaining data length */
                if (len > rlen)
                {
                    len = rlen;
                    col_append_fstr(pinfo->cinfo, COL_INFO, " [data len of block %d limited to %d]",
                                    data_cnt, len);
                    break;
                }
                dissect_bcp_data(bcp_tree, pinfo, tvb, &offset, len, segcode);
                rlen = tvb_captured_length_remaining(tvb, offset);
            }
            offset += rlen;
            break;
    }

    return offset;
}

/*
 * register dissector
 */
void
proto_register_bluecom(void)
{
    static hf_register_info hf_bcp[] = {
        /* BCP_PROTOCOL_HDR */
        { &hf_bcp_hdr_version, {
            "Version", "bluecom.hdr.version", FT_UINT8,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_hdr_format, {
            "Format", "bluecom.hdr.format", FT_UINT8,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_hdr_protflags, {
            "Flags", "bluecom.hdr.protflags", FT_UINT8,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_hdr_blocknb, {
            "BlockNb", "bluecom.hdr.blocknb", FT_UINT8,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_hdr_segcode, {
            "SegCode", "bluecom.hdr.segcode", FT_UINT16,
             BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_hdr_auth, {
            "Auth", "bluecom.hdr.auth", FT_UINT32,
             BASE_DEC_HEX, NULL, 0, NULL, HFILL }},

        /* BCP_BLOCK_HDR */
        { &hf_bcp_hdr_sourceid, {
            "SourceId", "bluecom.hdr.sourceid", FT_UINT16,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_hdr_destid, {
            "DestId", "bluecom.hdr.destid", FT_UINT16,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_hdr_transid, {
            "TransId", "bluecom.hdr.transid", FT_UINT16,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_hdr_cmd, {
            "Cmd", "bluecom.hdr.cmd", FT_UINT32,
            BASE_HEX, VALS(bcp_cmds), 0, NULL, HFILL }},
        { &hf_bcp_hdr_slavestate, {
            "SlaveState", "bluecom.hdr.slavestate", FT_UINT8,
             BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_hdr_blockflags, {
            "Flags", "bluecom.hdr.blockflags", FT_UINT8,
             BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_hdr_len, {
            "Len", "bluecom.hdr.len", FT_UINT8,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_hdr_fragoffset, {
            "FragOffset", "bluecom.hdr.fragoffset", FT_UINT16,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_hdr_timestamp, {
            "Timestamp", "bluecom.hdr.timestamp", FT_ABSOLUTE_TIME,
            ABSOLUTE_TIME_LOCAL, NULL, 0, NULL, HFILL }},

        /* BCP_SYNC_DATA */
        { &hf_bcp_sync_starttime, {
            "StartTime", "bluecom.sync.blockflags", FT_UINT32,
             BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_sync_cycletime, {
            "CycleTime", "bluecom.sync.cycletime", FT_UINT32,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_sync_dataratio, {
            "DataRatio", "bluecom.sync.dataratio", FT_UINT8,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_sync_identify, {
            "Identify", "bluecom.sync.identify", FT_BOOLEAN,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_sync_vlantag, {
            "VlanTag", "bluecom.sync.vlantag", FT_UINT16,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_sync_ethaddr, {
            "EthAddr", "bluecom.sync.ethaddr", FT_ETHER,
            BASE_NONE, NULL, 0, NULL, HFILL }},
        { &hf_bcp_sync_ethaddr2, {
            "EthAddr2", "bluecom.sync.ethaddr2", FT_ETHER,
            BASE_NONE, NULL, 0, NULL, HFILL }},

        /* BCP_IDENTIFY_REQ */
        { &hf_bcp_identify_error, {
            "Error", "bluecom.identify.error", FT_UINT32,
             BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_identify_starttime, {
            "StartTime", "bluecom.identify.starttime", FT_UINT32,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_identify_ipaddr, {
            "IpAddr", "bluecom.identify.ipaddr", FT_IPv4,
            BASE_NONE, NULL, 0, NULL, HFILL }},
        { &hf_bcp_identify_name, {
            "Name", "bluecom.identify.name", FT_STRING,
            STR_ASCII, NULL, 0, NULL, HFILL }},
        { &hf_bcp_identify_ethaddr, {
            "EthAddr", "bluecom.identify.ethaddr", FT_ETHER,
            BASE_NONE, NULL, 0, NULL, HFILL }},
        { &hf_bcp_identify_ethaddr2, {
            "EthAddr2", "bluecom.identify.ethaddr2", FT_ETHER,
            BASE_NONE, NULL, 0, NULL, HFILL }},

        /* BCP_SEARCH_REQ */
        { &hf_bcp_searchreq_addrtype, {
            "AddrType", "bluecom.searchreq.addrtype", FT_UINT32,
             BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_searchreq_reserved, {
            "Reserved", "bluecom.searchreq.reserved", FT_UINT32,
             BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_searchreq_name, {
            "Name", "bluecom.searchreq.name", FT_STRING,
            STR_ASCII, NULL, 0, NULL, HFILL }},
        { &hf_bcp_searchreq_ipaddrfirst, {
            "IpAddrFirst", "bluecom.searchreq.ipaddrfirst", FT_IPv4,
            BASE_NONE, NULL, 0, NULL, HFILL }},
        { &hf_bcp_searchreq_ipaddrlast, {
            "IpAddrLast", "bluecom.searchreq.ipaddrlast", FT_IPv4,
            BASE_NONE, NULL, 0, NULL, HFILL }},
        { &hf_bcp_searchreq_addrdata, {
            "Data", "bluecom.searchreq.addrdata", FT_BYTES,
            BASE_NONE, NULL, 0, NULL, HFILL }},

         /* BCP_SEARCH_RSP */
        { &hf_bcp_searchrsp_error, {
            "Error", "bluecom.searchrsp.error", FT_UINT32,
             BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_searchrsp_starttime, {
            "StartTime", "bluecom.searchrsp.starttime", FT_UINT32,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_searchrsp_lenin, {
            "LenIn", "bluecom.searchrsp.lenin", FT_UINT16,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_searchrsp_lenout, {
            "LenOut", "bluecom.searchrsp.lenout", FT_UINT16,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_searchrsp_ipaddr, {
            "IpAddr", "bluecom.searchrsp.ipaddr", FT_IPv4,
            BASE_NONE, NULL, 0, NULL, HFILL }},
        { &hf_bcp_searchrsp_name, {
            "Name", "bluecom.searchrsp.name", FT_STRING,
            STR_ASCII, NULL, 0, NULL, HFILL }},
        { &hf_bcp_searchrsp_ethaddr, {
            "EthAddr", "bluecom.searchrsp.ethaddr", FT_ETHER,
            BASE_NONE, NULL, 0, NULL, HFILL }},
        { &hf_bcp_searchrsp_ethaddr2, {
            "EthAddr2", "bluecom.searchrsp.ethaddr2", FT_ETHER,
            BASE_NONE, NULL, 0, NULL, HFILL }},

         /* BCP_CONNECT_REQ */
        { &hf_bcp_connectreq_lenin, {
            "LenIn", "bluecom.connectreq.lenin", FT_UINT16,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_connectreq_lenout, {
            "LenOut", "bluecom.connectreq.lenout", FT_UINT16,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_connectreq_cycletime, {
            "CycleTime", "bluecom.connectreq.cycletime", FT_UINT32,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_connectreq_offlinefactor, {
            "OfflineFactor", "bluecom.connectreq.offlinefactor", FT_UINT16,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_connectreq_ipaddr, {
            "IpAddr", "bluecom.connectreq.ipaddr", FT_IPv4,
            BASE_NONE, NULL, 0, NULL, HFILL }},
        { &hf_bcp_connectreq_name, {
            "Name", "bluecom.connectreq.name", FT_STRING,
            STR_ASCII, NULL, 0, NULL, HFILL }},
        { &hf_bcp_connectreq_ethaddr, {
            "EthAddr", "bluecom.connectreq.ethaddr", FT_ETHER,
            BASE_NONE, NULL, 0, NULL, HFILL }},
        { &hf_bcp_connectreq_ethaddr2, {
            "EthAddr2", "bluecom.connectreq.ethaddr2", FT_ETHER,
            BASE_NONE, NULL, 0, NULL, HFILL }},

         /* BCP_CONNECT_RSP */
        { &hf_bcp_connectrsp_error, {
            "Error", "bluecom.connectrsp.error", FT_UINT32,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_connectrsp_lenin, {
            "LenIn", "bluecom.connectrsp.lenin", FT_UINT16,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},
        { &hf_bcp_connectrsp_lenout, {
            "LenOut", "bluecom.connectrsp.lenout", FT_UINT16,
            BASE_DEC_HEX, NULL, 0, NULL, HFILL }},

        /* USERDATA */
        { &hf_bcp_userdata, {
            "BCP Userdata", "bluecom.userdata", FT_BYTES,
             BASE_NONE, NULL, 0, NULL, HFILL }}
    };

    /* define subtree elements - this is used for behavior of tree display  */
    static gint *ett[] = {
        &ett_bcp,
        &ett_bcp_header,
        &ett_bcp_blockheader,
        &ett_bcp_data,
    };

    /* register protocol */
    proto_bcp = proto_register_protocol("bluecom Protocol", "bluecom", "bluecom");

    /* register elements */
    proto_register_field_array(proto_bcp, hf_bcp, array_length(hf_bcp));
    /* register subtree elements  */
    proto_register_subtree_array(ett, array_length(ett));

    /* register dissector */
    bcp_handle = register_dissector("bluecom", dissect_bluecom, proto_bcp);

    /* add dissector table */
    bcp_subdissector_table = register_dissector_table("bluecomseg", "bluecom SegCode", proto_bcp,
                                                      FT_UINT8, BASE_DEC, DISSECTOR_TABLE_NOT_ALLOW_DUPLICATE);
}

/*
 * hand off dissector
 */
void
proto_reg_handoff_bluecom(void)
{
    /* Add dissector handle */
    dissector_add_uint("ethertype", ETHERTYPE_BLUECOM, bcp_handle);
}

/*
 * 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:
 */