/* packet-esio.c
 * Routines for Ether-S-I/O dissection (from Saia Burgess Controls AG )
 * Copyright 2010, Christian Durrer <christian.durrer@sensemail.ch>
 *
 * $Id$
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <glib.h>
#include <epan/packet.h>
#include <epan/expert.h>

/* Telegram types*/
#define ESIO_TRANSFER                  0x01
#define ESIO_STATUS                    0x02

/* Initialize the protocol and registered fields */
static int proto_esio = -1;
static int hf_esio_type = -1;
static int hf_esio_version = -1;
static int hf_esio_length = -1;
static int hf_esio_transaction_id = -1;
static int hf_esio_tlg_id = -1;
static int hf_esio_src_stn_id = -1;
static int hf_esio_data_nbr = -1;
static int hf_esio_data_flags = -1;
static int hf_esio_data_transfer_id = -1;
static int hf_esio_data_dest_id = -1;
static int hf_esio_data_length = -1;
static int hf_esio_data = -1;
static int hf_esio_sts_type = -1;
static int hf_esio_sts_size = -1;
static int hf_esio_rio_sts = -1;
static int hf_esio_rio_tlgs_lost = -1;
static int hf_esio_rio_diag = -1;
static int hf_esio_rio_flags = -1;

/* Initialize the subtree pointers */
static gint ett_esio = -1;
static gint ett_esio_header = -1;
static gint ett_esio_transfer_header = -1;
static gint ett_esio_transfer_data = -1;
static gint ett_esio_data = -1;

/* value to string definitions*/
/* Ether-S-I/O telegram types*/
static const value_string esio_tlg_types[] = {
       {0, "Reserved"},
       {1, "Data transfer telegram"},
       {2, "Status/Diag telegram"},
       {0, NULL}
};

/* Status telegram types*/
static const value_string esio_sts_types[] = {
       {0, "None"},
       {1, "RIO status"},
       {0, NULL}
};

/* check whether the packet looks like SBUS or not */
static gboolean
is_esio_pdu(tvbuff_t *tvb)
{
       /* we need at least 8 bytes to determine whether this is 
          Ether-S-I/O or not*/
       /* minimal length is 20 bytes*/
       if (tvb_length(tvb) < 20) {
              return FALSE;
       }
       /* First four bytes must be "ESIO"*/
       if (tvb_strneql(tvb, 0, "ESIO", 4) != 0) {
              return FALSE;
       }
       /* fifth byte must be 0*/
       if (tvb_get_guint8(tvb, 4) > 0x00) {
              return FALSE;
       }
       /* sixth byte indicates telegram type and must be 0, 1 or 2*/
       if (tvb_get_guint8(tvb, 5) > 0x02) {
              return FALSE;
       }
       /* seventh byte must be 0*/
       if (tvb_get_guint8(tvb, 6) > 0x00) {
              return FALSE;
       }
       /* eight byte indicates telegram version and must be 0 (up to now)*/
       if (tvb_get_guint8(tvb, 7) > 0x00) {
              return FALSE;
       }
       /*header seems to be Ether-S-I/O*/
       return TRUE;
}

/*Dissect the telegram*/
static int
dissect_esio(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{

/* Set up structures needed to add the protocol subtree and manage it */
       proto_item *ti, *et, *hi;
       proto_tree *esio_tree, *esio_header_tree, *esio_transfer_header_tree,
            *esio_data_tansfer_tree, *esio_data_tree;

       gint    i;
       gint    offset;
       guint8  esio_nbr_data_transfers;
       guint16 esio_telegram_type;
       guint16 esio_tlg_type;
       guint16 esio_transfer_length;
       guint32 esio_transfer_dest_id;
       guint32 esio_src_id;
       guint32 esio_dst_id;

/* does this look like an sbus pdu? */
       if (!is_esio_pdu(tvb)) {
              return 0;
       }

/* Make entries in Protocol column and Info column on summary display */
       col_set_str(pinfo->cinfo, COL_PROTOCOL, "ESIO");
       col_clear(pinfo->cinfo, COL_INFO);
       esio_telegram_type = tvb_get_guint8(tvb,5);
       if (check_col(pinfo->cinfo, COL_INFO)) {
              switch (esio_telegram_type) {
                     case ESIO_TRANSFER:
                            esio_src_id = tvb_get_ntohl(tvb,16);
                            esio_nbr_data_transfers = tvb_get_guint8(tvb, 20);
                            esio_dst_id = tvb_get_ntohl(tvb,26);
                            col_add_fstr( pinfo->cinfo, COL_INFO,
                                          "Data transfer: Src ID: %d, Dst ID(s): %d",
                                          esio_src_id, esio_dst_id);
                            if (esio_nbr_data_transfers > 1) {
                                   col_append_fstr( pinfo->cinfo, COL_INFO,
                                                    " ...");
                            }
                            break;
                     case ESIO_STATUS:
                            esio_src_id = tvb_get_ntohl(tvb,16);
                            col_add_fstr( pinfo->cinfo, COL_INFO,
                                          "Status/diag telegram: Src ID: %d",
                                          esio_src_id);
                            break;
                     default:
                            /* All other telegrams */
                            col_set_str( pinfo->cinfo, COL_INFO,
                                         "Unknown telegram");
                            break;
              }

       }
/* create display subtree for the protocol */
       if (tree) {
              offset =0;
              ti = proto_tree_add_item(tree, proto_esio, tvb, offset, -1, FALSE);
              esio_tree = proto_item_add_subtree(ti, ett_esio);
/*Add subtree for Ether-S-I/O header*/
              et = proto_tree_add_text(esio_tree, tvb, offset, 12, "Ether-S-I/O header");
              esio_header_tree = proto_item_add_subtree(et, ett_esio_header);
              offset +=4; /*first four bytes are "ESIO"*/
/* add items to the Ether-S-I/O header subtree*/
              esio_tlg_type = tvb_get_ntohs(tvb,offset);
              proto_tree_add_item(esio_header_tree,
                                  hf_esio_type, tvb, offset, 2, FALSE);
              offset += 2;
              proto_tree_add_item(esio_header_tree,
                                  hf_esio_version, tvb, offset, 2, FALSE);
              offset += 2;
              proto_tree_add_item(esio_header_tree,
                                  hf_esio_length, tvb, offset, 2, FALSE);
              offset += 2;
              proto_tree_add_item(esio_header_tree,
                                  hf_esio_transaction_id, tvb, offset, 2, FALSE);
              offset += 2;
              switch (esio_tlg_type) {
                     case ESIO_TRANSFER:
                            /*Add subtree for Ether-S-I/O header*/
                            et = proto_tree_add_text(esio_tree, tvb, offset, 12, "Transfer header");
                            esio_transfer_header_tree = proto_item_add_subtree(et, ett_esio_transfer_header);
                            proto_tree_add_item(esio_transfer_header_tree,
                                                hf_esio_tlg_id, tvb, offset, 4, FALSE);
                            offset += 4;
                            proto_tree_add_item(esio_transfer_header_tree,
                                                hf_esio_src_stn_id, tvb, offset, 4, FALSE);
                            offset += 4;
                            esio_nbr_data_transfers = tvb_get_guint8(tvb,offset);
                            proto_tree_add_item(esio_transfer_header_tree,
                                                hf_esio_data_nbr, tvb, offset, 1, FALSE);
                            offset += 1;
                            proto_tree_add_item(esio_transfer_header_tree,
                                                hf_esio_data_flags, tvb, offset, 1, FALSE);
                            offset += 1;
                            for (i=((esio_nbr_data_transfers)); i>0; i--) {
                                   /*Add subtree(s) for Ether-S-I/O data transfers*/
                                   esio_transfer_dest_id = tvb_get_ntohl(tvb,(offset+4));
                                   esio_transfer_length = tvb_get_ntohs(tvb,(offset+8));
                                   et = proto_tree_add_text(esio_tree, tvb, offset,
                                                            (esio_transfer_length + 10), "Data transfer to ID: %d ",
                                                            esio_transfer_dest_id);
                                   esio_data_tansfer_tree = proto_item_add_subtree(et, ett_esio_transfer_data);
                                   proto_tree_add_item(esio_data_tansfer_tree,
                                                       hf_esio_data_transfer_id, tvb, offset, 4, FALSE);
                                   offset += 4;
                                   proto_tree_add_item(esio_data_tansfer_tree,
                                                       hf_esio_data_dest_id, tvb, offset, 4, FALSE);
                                   offset += 4;
                                   proto_tree_add_item(esio_data_tansfer_tree,
                                                       hf_esio_data_length, tvb, offset, 2, FALSE);
                                   offset += 2;
                                   /*here comes the data*/
                                   et = proto_tree_add_text(esio_data_tansfer_tree, tvb, offset,
                                                            esio_transfer_length, "Data bytes ");
                                   esio_data_tree = proto_item_add_subtree(et, ett_esio_data);
                                   for (i=((esio_transfer_length)); i>0; i--) {
                                          proto_tree_add_item(esio_data_tree,
                                                              hf_esio_data, tvb, offset,
                                                              1, FALSE);
                                          offset += 1;
                                   }
                            }
                            break;
                     case ESIO_STATUS:
                            proto_tree_add_item(esio_tree,
                                                hf_esio_sts_type, tvb, offset, 2, FALSE);
                            offset += 2;
                            proto_tree_add_item(esio_tree,
                                                hf_esio_sts_size, tvb, offset, 2, FALSE);
                            offset += 2;
                            proto_tree_add_item(esio_tree,
                                                hf_esio_src_stn_id, tvb, offset, 4, FALSE);
                            offset += 4;
                            proto_tree_add_item(esio_tree,
                                                hf_esio_rio_sts, tvb, offset,
                                                1, FALSE);
                            offset += 1;
                            hi = proto_tree_add_item(esio_tree,
                                                     hf_esio_rio_tlgs_lost, tvb, offset,
                                                     1, FALSE);
                            expert_add_info_format(pinfo, hi, PI_SEQUENCE, PI_NOTE,
                                                   "Telegram(s) lost");
                            offset += 1;
                            proto_tree_add_item(esio_tree,
                                                hf_esio_rio_diag, tvb, offset,
                                                1, FALSE);
                            offset += 1;
                            proto_tree_add_item(esio_tree,
                                                hf_esio_rio_flags, tvb, offset, 1, FALSE);
                            offset += 1;
                            break;
                     default:
                            break;
              }
       } /*end of tree*/
       return tvb_length(tvb);
/*End of dissect_sbus*/
}

/* Register the protocol with Wireshark */
void
proto_register_esio(void)
{
/* Setup list of header fields  See Section 1.6.1 for details*/
       static hf_register_info hf[] = {
              { &hf_esio_type,
                     { "Telegram type", "esio.type",
                     FT_UINT16, BASE_HEX, VALS(esio_tlg_types), 0,
                     NULL, HFILL }
              },

              { &hf_esio_version,
                     { "Version", "esio.vers",
                     FT_UINT16, BASE_DEC, NULL, 0,
                     NULL, HFILL }
              },

              { &hf_esio_length,
                     { "Length (bytes)", "esio.len",
                     FT_UINT16, BASE_DEC, NULL, 0,
                     NULL, HFILL }
              },

              { &hf_esio_transaction_id,
                     { "Transaction ID", "esio.transaction_id",
                     FT_UINT16, BASE_DEC, NULL, 0,
                     NULL, HFILL }
              },

              { &hf_esio_src_stn_id,
                     { "Source station ID", "esio.src_stn_id",
                     FT_UINT32, BASE_DEC, NULL, 0,
                     NULL, HFILL }
              },

              { &hf_esio_tlg_id,
                     { "Telegram ID", "esio.transfer.tlg_id",
                     FT_UINT32, BASE_DEC, NULL, 0,
                     NULL, HFILL }
              },

              { &hf_esio_data_nbr,
                     { "Nbr. of data transfers", "esio.data.nbr",
                     FT_UINT8, BASE_DEC, NULL, 0,
                     NULL, HFILL }
              },

              { &hf_esio_data_flags,
                     { "Transfer header flags", "esio.data.flags",
                     FT_UINT8, BASE_HEX, NULL, 0,
                     NULL, HFILL }
              },

              { &hf_esio_data_transfer_id,
                     { "Data transfer ID", "esio.data.transfer_id",
                     FT_UINT32, BASE_DEC, NULL, 0,
                     NULL, HFILL }
              },

              { &hf_esio_data_dest_id,
                     { "Data destination ID", "esio.data.destination_id",
                     FT_UINT32, BASE_DEC, NULL, 0,
                     NULL, HFILL }
              },

              { &hf_esio_data_length,
                     { "Data transfer length", "esio.data.length",
                     FT_UINT16, BASE_DEC, NULL, 0,
                     NULL, HFILL }
              },

              { &hf_esio_data,
                     { "Data", "esio.data",
                     FT_UINT8, BASE_DEC, NULL, 0,
                     NULL, HFILL }
              },

              { &hf_esio_sts_type,
                     { "Status type", "esio.sts.type",
                     FT_UINT16, BASE_HEX, VALS(esio_sts_types), 0,
                     NULL, HFILL }
              },

              { &hf_esio_sts_size,
                     { "Status length (bytes)", "esio.sts.length",
                     FT_UINT16, BASE_DEC, NULL, 0,
                     NULL, HFILL }
              },

              { &hf_esio_rio_sts,
                     { "RIO status", "esio.sts.rio_sts",
                     FT_UINT8, BASE_DEC, NULL, 0,
                     NULL, HFILL }
              },

              { &hf_esio_rio_tlgs_lost,
                     { "Lost telegrams to RIO", "esio.sts.rio_lost_tlg",
                     FT_UINT8, BASE_DEC, NULL, 0,
                     NULL, HFILL }
              },

              { &hf_esio_rio_diag,
                     { "RIO diagnostics", "esio.sts.rio_diag",
                     FT_UINT8, BASE_DEC, NULL, 0,
                     NULL, HFILL }
              },

              { &hf_esio_rio_flags,
                     { "RIO flags", "esio.sts.rio_flags",
                     FT_UINT8, BASE_HEX, NULL, 0,
                     NULL, HFILL }
              }
       };


/* Setup protocol subtree array */
       static gint *ett[] = {
              &ett_esio,
              &ett_esio_header,
              &ett_esio_transfer_header,
              &ett_esio_transfer_data,
              &ett_esio_data
       };

/* Register the protocol name and description */
       proto_esio = proto_register_protocol("SAIA Ether-S-I/O protocol", "ESIO", "esio");

/* Required function calls to register the header fields and subtrees used */
       proto_register_field_array(proto_esio, hf, array_length(hf));
       proto_register_subtree_array(ett, array_length(ett));
}

void
proto_reg_handoff_esio(void)
{
       dissector_handle_t esio_handle;

       esio_handle = new_create_dissector_handle(dissect_esio, proto_esio);
       dissector_add_uint("udp.port", 6060, esio_handle);
}

/*
 * Editor modelines
 *
 * Local Variables:
 * c-basic-offset: 7
 * tab-width: 8
 * indent-tabs-mode: nil
 * End:
 *
 * ex: set shiftwidth=7 tabstop=8 expandtab
 * :indentSize=7:tabSize=8:noTabs=true:
 */
