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

#include "config.h"

#include <epan/packet.h>
#include <epan/etypes.h>
#include <epan/to_str.h>
#include <epan/exceptions.h>
#include <epan/show_exception.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 int proto_bcp;
static int ett_bcp;
static int ett_bcp_header;
static int ett_bcp_blockheader;
static int ett_bcp_data;

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

static int hf_bcp_sync_starttime;
static int hf_bcp_sync_cycletime;
static int hf_bcp_sync_dataratio;
static int hf_bcp_sync_identify;
static int hf_bcp_sync_vlantag;
static int hf_bcp_sync_ethaddr;
static int hf_bcp_sync_ethaddr2;

static int hf_bcp_identify_error;
static int hf_bcp_identify_starttime;
static int hf_bcp_identify_ipaddr;
static int hf_bcp_identify_name;
static int hf_bcp_identify_ethaddr;
static int hf_bcp_identify_ethaddr2;

static int hf_bcp_searchreq_addrtype;
static int hf_bcp_searchreq_reserved;
static int hf_bcp_searchreq_name;
static int hf_bcp_searchreq_ipaddrfirst;
static int hf_bcp_searchreq_ipaddrlast;
static int hf_bcp_searchreq_addrdata;

static int hf_bcp_searchrsp_error;
static int hf_bcp_searchrsp_starttime;
static int hf_bcp_searchrsp_lenin;
static int hf_bcp_searchrsp_lenout;
static int hf_bcp_searchrsp_ipaddr;
static int hf_bcp_searchrsp_name;
static int hf_bcp_searchrsp_ethaddr;
static int hf_bcp_searchrsp_ethaddr2;

static int hf_bcp_connectreq_lenin;
static int hf_bcp_connectreq_lenout;
static int hf_bcp_connectreq_cycletime;
static int hf_bcp_connectreq_offlinefactor;
static int hf_bcp_connectreq_ipaddr;
static int hf_bcp_connectreq_name;
static int hf_bcp_connectreq_ethaddr;
static int hf_bcp_connectreq_ethaddr2;

static int hf_bcp_connectrsp_error;
static int hf_bcp_connectrsp_lenin;
static int hf_bcp_connectrsp_lenout;

static int hf_bcp_userdata;

/* 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 (block data), flags (req or rsp)
 * return: nothing
 */
static void
dissect_bcp_connect_data(packet_info *pinfo, proto_tree *bcp_tree, tvbuff_t *tvb, int flags)
{
    proto_tree *bcp_subtree = NULL;
    unsigned offset = 0;
    unsigned offset_base = offset;
    unsigned len = tvb_reported_length(tvb);

    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(pinfo->pool, tvb, offset + 16, BCP_NAME_LEN, ENC_ASCII),
                                                    tvb_ip_to_str(pinfo->pool, 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);
        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);
    }
}

/*
 * dissector function of search data (request and response)
 *
 * input: tree, buffer (block data) flags (req or rsp)
 * return: nothing
 */
static void
dissect_bcp_search_data(packet_info *pinfo, proto_tree *bcp_tree, tvbuff_t *tvb, int flags)
{
    proto_tree *bcp_subtree = NULL;
    unsigned type = 0;
    unsigned offset = 0;
    unsigned offset_base = offset;
    unsigned len = tvb_reported_length(tvb);

    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(pinfo->pool, tvb, offset + 8),
                                  tvb_ip_to_str(pinfo->pool, 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(pinfo->pool, 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);
                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(pinfo->pool, tvb, offset + 16, BCP_NAME_LEN, ENC_ASCII),
                          tvb_ip_to_str(pinfo->pool, 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);
        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);
        }
    }
}

/*
 * dissector function of identify data (request)
 *
 * input: tree, buffer (block data), flags (req or rsp)
 * return: nothing
 */
static void
dissect_bcp_identify_data(packet_info *pinfo, proto_tree *bcp_tree, tvbuff_t *tvb)
{
    proto_tree *bcp_subtree = NULL;
    unsigned offset = 0;
    unsigned offset_base = offset;
    unsigned len = tvb_reported_length(tvb);

    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(pinfo->pool, tvb, offset + 12, BCP_NAME_LEN, ENC_ASCII),
                    tvb_ip_to_str(pinfo->pool, 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);
    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);
    }
}

/*
 * dissector function of sync data
 *
 * input: tree, buffer (block data)
 * return: nothing
 */
static void
dissect_bcp_sync_data(proto_tree *bcp_tree, tvbuff_t *tvb)
{
    proto_tree *bcp_subtree = NULL;
    unsigned offset = 0;
    unsigned offset_base = offset;
    unsigned len = tvb_reported_length(tvb);

    bcp_subtree = proto_tree_add_subtree_format(bcp_tree, tvb, offset, len, ett_bcp_data, NULL,
                                             "BCP Sync Data: Identify=%s",
                                             BOOLSTR(tvb_get_uint8(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);
    }
}

/*
 * dissector function of data command
 *
 * input: tree, buffer (block data)
 * return: nothing
 */
static void
dissect_bcp_data(proto_tree *bcp_tree, packet_info *pinfo, tvbuff_t *tvb,
                 unsigned segcode)
{
    dissector_handle_t  handle;

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

    if (handle)
    {
        /* Call the sub-dissector. */
        call_dissector(handle, tvb, pinfo, bcp_tree);
    }
    else
    {
        proto_tree_add_item(bcp_tree, hf_bcp_userdata, tvb, 0, -1, ENC_NA);
    }
}


/*
 * dissector function of block header
 *
 * input: tree, buffer (data), offset (data pointer), number of header block
 * output: command from header, length of following data
 * return: updated offset
 */
static unsigned
dissect_bcp_block_header(proto_tree *bcp_tree, tvbuff_t *tvb, unsigned offset,
                         unsigned blocknb, unsigned *cmd, unsigned *len)
{
    proto_tree *bcp_subtree = NULL;

    *cmd = tvb_get_uint8(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 (%u): Cmd=%s (%u), Len=%u",
               blocknb,
               val_to_str_const(*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;
    return offset;
}

/*
 * dissector function of protocol header
 *
 * input: tree, buffer (data), offset (data pointer)
 * output: flags, block count, segcode from header
 * return: updated offset
 */
static unsigned
dissect_bcp_protocol_header(proto_tree *bcp_tree, tvbuff_t *tvb,
                            unsigned offset, int *flags, unsigned *blocknb,
                            unsigned *segcode)
{
    proto_tree *bcp_subtree = NULL;

    *flags = tvb_get_uint8(tvb, offset + 2);
    *blocknb = tvb_get_uint8(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",
                                                *blocknb,
                                                *segcode);

    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;
    return offset;
}


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

    /* 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  */
    offset = dissect_bcp_protocol_header(bcp_tree, tvb, offset, &flags, &blocknb, &segcode);

    /* set info column */
    col_append_fstr(pinfo->cinfo, COL_INFO, "segcode=%u blocks=%u",
                    segcode, blocknb);

    /* Iterate over blocks */
    for (block = 0; block < blocknb; block++)
    {
        /* BCP block header*/
        offset = dissect_bcp_block_header(bcp_tree, tvb, offset, block, &cmd, &len);

        /* append text to BCP base */
        proto_item_append_text(bcp_item_base, ", %s (%u) len=%u",
                               val_to_str_const(cmd, bcp_cmds, "UNKNOWN"), cmd, len);

        block_tvb = tvb_new_subset_length(tvb, offset, len);
        TRY {
            switch (cmd)
            {
            case BCP_BLK_CMD_SYNC:
                dissect_bcp_sync_data(bcp_tree, block_tvb);
                break;

            case BCP_BLK_CMD_IDENTIFY:
                dissect_bcp_identify_data(pinfo, bcp_tree, block_tvb);
                break;

            case BCP_BLK_CMD_SEARCH:
                col_append_str(pinfo->cinfo, COL_INFO, REQRSP(flags));
                dissect_bcp_search_data(pinfo, bcp_tree, block_tvb, flags);
                break;

            case BCP_BLK_CMD_CONNECT:
                col_append_str(pinfo->cinfo, COL_INFO, REQRSP(flags));
                dissect_bcp_connect_data(pinfo, bcp_tree, block_tvb, flags);
                break;

            case BCP_BLK_CMD_DATA:
            default:
                dissect_bcp_data(bcp_tree, pinfo, block_tvb, segcode);
                break;
            }
        } CATCH_NONFATAL_ERRORS {
            /*
             * Somebody threw an exception that means that there was
             * a problem dissecting the block. Just show the exception
             * and then continue to dissect blocks.
             */
            show_exception(block_tvb, pinfo, tree, EXCEPT_CODE, GET_MESSAGE);
        } ENDTRY;
	offset += len;
    }

    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_UINT8,
            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_UINT16,
            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_NONE, 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,
            BASE_NONE, 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,
            BASE_NONE, 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,
            BASE_NONE, 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,
            BASE_NONE, 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 int *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);
}

/*
 * 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:
 */