/* -*- Mode: C; tab-width: 2 -*- */
/* packet-reload-framing.c
 * Routines for REsource LOcation And Discovery (RELOAD) Framing
 * Author: Stephane Bryant <sbryant@glycon.org>
 * Copyright 2010 Stonyfish Inc.
 *
 * $Id: packet-reload-framing.c 37110 2011-05-13 02:48:08Z morriss $
 *
 * 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.
 *
 * Please refer to the following specs for protocol detail:
 * - draft-ietf-p2psip-base-13
 */

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

#include <epan/conversation.h>
#include <epan/expert.h>
#include <packet-tcp.h>

/* Initialize the protocol and registered fields */
static int proto_reload_framing = -1;

static int hf_reload_framing_type = -1;
static int hf_reload_framing_sequence = -1;
static int hf_reload_framing_ack_sequence = -1;
static int hf_reload_framing_message = -1;
static int hf_reload_framing_message_length = -1;
static int hf_reload_framing_received = -1;
static int hf_reload_framing_duplicate = -1;
static int hf_reload_framing_response_in = -1;
static int hf_reload_framing_response_to = -1;
static int hf_reload_framing_time = -1;

static dissector_handle_t reload_handle;

/* Structure containing transaction specific information */
typedef struct _reload_frame_t {
  guint32 data_frame;
  guint32 ack_frame;
  nstime_t req_time;
} reload_frame_t;

/* Structure containing conversation specific information */
typedef struct _reload_frame_conv_info_t {
  emem_tree_t *transaction_pdus;
} reload_conv_info_t;


/* RELOAD Message classes = (message_code & 0x1) (response = request +1) */
#define DATA            128
#define ACK             129


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


#define UDP_PORT_RELOAD                 6084
#define TCP_PORT_RELOAD                 6084

#define MIN_HDR_LENGTH                             9
#define MIN_RELOADDATA_HDR_LENGTH                  38

#define RELOAD_TOKEN                    0xd2454c4f

static const value_string types[] = {
  {DATA, "DATA"},
  {ACK,  "ACK"},
  {0x00, NULL}
};

static guint
get_reload_framing_message_length(packet_info *pinfo _U_, tvbuff_t *tvb, int offset)
{
  /* Get the type */
  guint32 length = 9;


  if (tvb_get_guint8(tvb, offset) == DATA) {

    length = 1 + 4;
    length += 3;
    length += (tvb_get_ntohs(tvb, 1 + 4)<<8)+ tvb_get_guint8(tvb, 1 + 4 + 2);
  }

  return length;
}


static int
dissect_reload_framing_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
  proto_item *ti;
  proto_tree *reload_framing_tree;
  guint32 relo_token;
  guint32 message_length=0;
  guint32 sequence;
  guint effective_length;
  guint16 offset;
  conversation_t *conversation;
  reload_conv_info_t *reload_framing_info;
  reload_frame_t * reload_frame;
  guint8 type;

  offset = 0;
  effective_length = tvb_length(tvb);

  /* First, make sure we have enough data to do the check. */
  if (effective_length < MIN_HDR_LENGTH)
    return 0;

  /* Get the type
   * http://tools.ietf.org/html/draft-ietf-p2psip-base-12
   * 5.6.2.  Framing Header
   */
  type = tvb_get_guint8(tvb, 0);

  switch(type){
    case DATA:
      /* in the data type, check the reload token to be sure this
      *  is a reLoad packet
      */
      message_length = (tvb_get_ntohs(tvb, 1 + 4)<<8)+ tvb_get_guint8(tvb, 1 + 4 + 2);
      if (message_length < MIN_RELOADDATA_HDR_LENGTH) {
        return 0;
      }
      relo_token = tvb_get_ntohl(tvb,1 + 4 + 3);
      if (relo_token != RELOAD_TOKEN) {
        return 0;
      }
      break;
    case ACK:
      if (effective_length < 9) {
        return 0;
      }
      break;
    default:
      return 0;
  }


  /* The message seems to be a valid RELOAD framing message! */

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

  /* Create the transaction key which may be used to track the conversation */
  sequence = tvb_get_ntohl(tvb, 1);

  conversation = find_or_create_conversation(pinfo);

  /*
   * Do we already have a state structure for this conv
   */
  reload_framing_info = conversation_get_proto_data(conversation, proto_reload_framing);
  if (!reload_framing_info) {
    /* No.  Attach that information to the conversation, and add
     * it to the list of information structures.
     */
    reload_framing_info = se_alloc(sizeof(reload_conv_info_t));
    reload_framing_info->transaction_pdus = se_tree_create_non_persistent(EMEM_TREE_TYPE_RED_BLACK, "reload_framing_transaction_pdus");
    conversation_add_proto_data(conversation, proto_reload_framing, reload_framing_info);
  }

  if (!pinfo->fd->flags.visited) {
    if ((reload_frame =
         se_tree_lookup32(reload_framing_info->transaction_pdus, sequence)) == NULL) {
      reload_frame = se_alloc(sizeof(reload_frame_t));
      reload_frame->data_frame = 0;
      reload_frame->ack_frame = 0;
      reload_frame->req_time = pinfo->fd->abs_ts;
      se_tree_insert32(reload_framing_info->transaction_pdus, sequence, (void *)reload_frame);
    }

    /* check whether the message is a request or a response */

    if (type == DATA) {
      /* This is a data */
      if (reload_frame->data_frame == 0) {
        reload_frame->data_frame = pinfo->fd->num;
      }
    }
    else {
      /* This is a catch-all for all non-request messages */
      if (reload_frame->ack_frame == 0) {
        reload_frame->ack_frame = pinfo->fd->num;
      }
    }
  }
  else {
    reload_frame=se_tree_lookup32(reload_framing_info->transaction_pdus, sequence);
  }

  if (!reload_frame) {
    /* create a "fake" pana_trans structure */
    reload_frame = ep_alloc(sizeof(reload_frame_t));
    reload_frame->data_frame = 0;
    reload_frame->ack_frame = 0;
    reload_frame->req_time = pinfo->fd->abs_ts;
  }

  ti = proto_tree_add_item(tree, proto_reload_framing, tvb, 0, -1, FALSE);

  reload_framing_tree = proto_item_add_subtree(ti, ett_reload_framing);

  col_add_fstr(pinfo->cinfo, COL_INFO, "%s", val_to_str(type, types, "Unknown"));
  proto_item_append_text(ti, ": %s", val_to_str(type, types, "Unknown"));

  /* Retransmission control */
  if (type == DATA) {
    if (reload_frame->data_frame != pinfo->fd->num) {
      proto_item *it;
      it = proto_tree_add_uint(reload_framing_tree, hf_reload_framing_duplicate, tvb, 0, 0, reload_frame->data_frame);
      PROTO_ITEM_SET_GENERATED(it);
    }
    if (reload_frame->ack_frame) {
      proto_item *it;
      it = proto_tree_add_uint(reload_framing_tree, hf_reload_framing_response_in, tvb, 0, 0, reload_frame->ack_frame);
      PROTO_ITEM_SET_GENERATED(it);
    }
  }
  else {
    /* This is a response */
    if (reload_frame->ack_frame != pinfo->fd->num) {
      proto_item *it;
      it = proto_tree_add_uint(reload_framing_tree, hf_reload_framing_duplicate, tvb, 0, 0, reload_frame->ack_frame);
      PROTO_ITEM_SET_GENERATED(it);
    }

    if (reload_frame->data_frame) {
      proto_item *it;
      nstime_t ns;

      it = proto_tree_add_uint(reload_framing_tree, hf_reload_framing_response_to, tvb, 0, 0, reload_frame->data_frame);
      PROTO_ITEM_SET_GENERATED(it);

      nstime_delta(&ns, &pinfo->fd->abs_ts, &reload_frame->req_time);
      it = proto_tree_add_time(reload_framing_tree, hf_reload_framing_time, tvb, 0, 0, &ns);
      PROTO_ITEM_SET_GENERATED(it);
    }
  }

  /*
   * Message dissection
   */
  proto_tree_add_item(reload_framing_tree, hf_reload_framing_type, tvb, offset , 1, FALSE);
  offset += 1;
  switch (type) {

  case DATA:
    {
      tvbuff_t *next_tvb;

      proto_tree_add_item(reload_framing_tree, hf_reload_framing_sequence, tvb, offset , 4, FALSE);
      offset += 4;
      proto_tree_add_item(reload_framing_tree, hf_reload_framing_message_length, tvb, offset, 3, FALSE);
      offset += 3;
      next_tvb = tvb_new_subset(tvb, offset, effective_length - offset, message_length);
      if (reload_handle == NULL) {
        expert_add_info_format(pinfo, ti, PI_PROTOCOL, PI_WARN, "Can not find reload dissector");
        return tvb_length(tvb);
      }
      call_dissector_only(reload_handle, next_tvb, pinfo, tree);
    }
    break;

  case ACK:
    proto_tree_add_item(reload_framing_tree, hf_reload_framing_ack_sequence, tvb, offset , 4, FALSE);
    offset += 4;
    proto_tree_add_item(reload_framing_tree, hf_reload_framing_received, tvb, offset , 4, FALSE);
    break;

  default:
    DISSECTOR_ASSERT_NOT_REACHED();
  }

  return tvb_length(tvb);
}

static int
dissect_reload_framing_udp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
  return dissect_reload_framing_message(tvb, pinfo, tree);
}

static void
dissect_reload_framing_message_no_return(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
  dissect_reload_framing_message(tvb, pinfo, tree);
}

static void
dissect_reload_framing_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
  /* XXX: Check if we have a valid RELOAD Frame Type ? */
  tcp_dissect_pdus(tvb, pinfo, tree, TRUE, MIN_HDR_LENGTH,
                   get_reload_framing_message_length, dissect_reload_framing_message_no_return);
}

static gboolean
dissect_reload_framing_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
  if (dissect_reload_framing_message(tvb, pinfo, tree) == 0) {
    /*
     * It wasn't a valid RELOAD message, and wasn't
     * dissected as such.
     */
    return FALSE;
  }
  return TRUE;
}

void
proto_register_reload_framing(void)
{

  static hf_register_info hf[] = {
    { &hf_reload_framing_type,
      { "Framed Message Type", "reload_framing.type", FT_UINT8,
        BASE_DEC, VALS(types),  0x0,  NULL, HFILL }
    },
    { &hf_reload_framing_sequence,
      { "Sequence", "reload_framing.sequence", FT_UINT32,
        BASE_DEC, NULL, 0x0,  NULL, HFILL }
    },
    { &hf_reload_framing_ack_sequence,
      { "ACK Sequence", "reload_framing.ack_sequence", FT_UINT32,
        BASE_DEC, NULL, 0x0,  NULL, HFILL }
    },
    { &hf_reload_framing_message,
      { "Message", "reload_framing.message", FT_BYTES,
        BASE_NONE, NULL, 0x0,  NULL, HFILL }
    },
    { &hf_reload_framing_message_length,
      { "Message length", "reload_framing.message.length", FT_UINT32,
        BASE_DEC, NULL, 0x0,  NULL, HFILL }
    },
    { &hf_reload_framing_received,
      { "Received", "reload_framing.received", FT_UINT32,
        BASE_HEX, NULL, 0x0,  NULL, HFILL }
    },
    { &hf_reload_framing_response_in,
      { "Response In",  "reload_framing.response-in", FT_FRAMENUM,
        BASE_NONE, NULL, 0x0, "The response to this RELOAD Request is in this frame", HFILL }
    },
    { &hf_reload_framing_response_to,
      { "Request In", "reload_framing.response-to", FT_FRAMENUM,
        BASE_NONE, NULL, 0x0, "This is a response to the RELOAD Request in this frame", HFILL }
    },
    { &hf_reload_framing_time,
      { "Time", "reload_framing.time", FT_RELATIVE_TIME,
        BASE_NONE, NULL, 0x0, "The time between the Request and the Response", HFILL }
    },
    { &hf_reload_framing_duplicate,
      { "Duplicated original message in", "reload_framing.duplicate", FT_FRAMENUM,
        BASE_NONE, NULL, 0x0, "This is a duplicate of RELOAD message in this frame", HFILL }
    },
  };

  /* Setup protocol subtree array */
  static gint *ett[] = {
    &ett_reload_framing,
    &ett_reload_framing_message,
  };

  /* Register the protocol name and description */
  proto_reload_framing = proto_register_protocol("REsource LOcation And Discovery Framing", "RELOAD FRAMING", "reload-framing");

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

  register_dissector("reload-framing", dissect_reload_framing_message_no_return, proto_reload_framing);

}

void
proto_reg_handoff_reload_framing(void)
{

  dissector_handle_t reload_framing_tcp_handle;
  dissector_handle_t reload_framing_udp_handle;

  reload_framing_tcp_handle = create_dissector_handle(dissect_reload_framing_tcp, proto_reload_framing);
  reload_framing_udp_handle = new_create_dissector_handle(dissect_reload_framing_udp, proto_reload_framing);

  reload_handle = find_dissector("reload");

  dissector_add_uint("tcp.port", TCP_PORT_RELOAD, reload_framing_tcp_handle);
  dissector_add_uint("udp.port", UDP_PORT_RELOAD, reload_framing_udp_handle);

  heur_dissector_add("udp", dissect_reload_framing_heur, proto_reload_framing);
  heur_dissector_add("tcp", dissect_reload_framing_heur, proto_reload_framing);
  heur_dissector_add("dtls", dissect_reload_framing_heur, proto_reload_framing);
}

