C++ dissector_try_uint函数代码示例

static void
decode_pgm_ports(tvbuff_t *tvb, int offset, packet_info *pinfo,
	proto_tree *tree, guint16 pgmhdr_sport, guint16 pgmhdr_dport)
{
  tvbuff_t *next_tvb;
  int found = 0;

  next_tvb = tvb_new_subset_remaining(tvb, offset);

  /* do lookup with the subdissector table */
  found = dissector_try_uint(subdissector_table, pgmhdr_sport,
			next_tvb, pinfo, tree);
  if (found)
	return;

  found = dissector_try_uint(subdissector_table, pgmhdr_dport,
			next_tvb, pinfo, tree);
  if (found)
	return;

  /* do lookup with the heuristic subdissector table */
  if (dissector_try_heuristic(heur_subdissector_list, next_tvb, pinfo, tree))
	return;

  /* Oh, well, we don't know this; dissect it as data. */
  call_dissector(data_handle,next_tvb, pinfo, tree);
}

static void dissect_osi_juniper(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
    guint8     nlpid;
    tvbuff_t   *next_tvb;

    nlpid = tvb_get_guint8(tvb, 0);
    if(dissector_try_uint(osinl_incl_subdissector_table, nlpid, tvb, pinfo, tree))
        return;

    next_tvb = tvb_new_subset_remaining(tvb, 1);
    dissector_try_uint(osinl_excl_subdissector_table, nlpid, next_tvb, pinfo, tree);
}

static void dissect_osi(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
    guint8    nlpid;
    tvbuff_t *new_tvb;

    pinfo->current_proto = "OSI";

    nlpid = tvb_get_guint8(tvb, 0);

    /*
     * Try the subdissector table for protocols in which the NLPID is
     * considered part of the PDU; it should be handed a tvbuff that
     * includes the NLPID, and should put the NLPID into the protocol
     * tree itself.
     */
    if (dissector_try_uint(osinl_incl_subdissector_table, nlpid, tvb, pinfo, tree))
        return;

    /*
     * Try the subdissector table for protocols in which the NLPID is
     * *not* considered part of the PDU; it should be handed a tvbuff
     * that doesn't include the NLPID, and we should put the NLPID into
     * the protocol tree ourselves.
     */
    proto_tree_add_uint(tree, hf_osi_nlpid, tvb, 0, 1, nlpid);
    new_tvb = tvb_new_subset_remaining(tvb, 1);
    if (dissector_try_uint(osinl_excl_subdissector_table, nlpid, new_tvb, pinfo, tree))
        return;

    switch (nlpid) {

    /* ESIS (X.25) is not currently decoded */

    case NLPID_ISO9542X25_ESIS:
        col_set_str(pinfo->cinfo, COL_PROTOCOL, "ESIS (X.25)");
        call_dissector(data_handle,tvb, pinfo, tree);
        break;
    case NLPID_ISO10747_IDRP:
        col_set_str(pinfo->cinfo, COL_PROTOCOL, "IDRP");
        call_dissector(data_handle,tvb, pinfo, tree);
        break;
    default:
        col_set_str(pinfo->cinfo, COL_PROTOCOL, "ISO");
        col_add_fstr(pinfo->cinfo, COL_INFO, "Unknown ISO protocol (%02x)", nlpid);

        call_dissector(data_handle,tvb, pinfo, tree);
        break;
    }
} /* dissect_osi */

void
chdlctype(guint16 chdlc_type, tvbuff_t *tvb, int offset_after_chdlctype,
          packet_info *pinfo, proto_tree *tree, proto_tree *fh_tree,
          int chdlctype_id)
{
  tvbuff_t *next_tvb;
  int       padbyte;

  proto_tree_add_uint(fh_tree, chdlctype_id, tvb,
                        offset_after_chdlctype - 2, 2, chdlc_type);

  padbyte = tvb_get_guint8(tvb, offset_after_chdlctype);
  if (chdlc_type == CHDLCTYPE_OSI &&
    !( padbyte == NLPID_ISO8473_CLNP || /* older Juniper SW does not send a padbyte */
       padbyte == NLPID_ISO9542_ESIS ||
       padbyte == NLPID_ISO10589_ISIS)) {
    /* There is a Padding Byte for CLNS protocols over Cisco HDLC */
    proto_tree_add_item(fh_tree, hf_chdlc_clns_padding, tvb, offset_after_chdlctype, 1, ENC_BIG_ENDIAN);
    next_tvb = tvb_new_subset_remaining(tvb, offset_after_chdlctype + 1);
  } else {
    next_tvb = tvb_new_subset_remaining(tvb, offset_after_chdlctype);
  }

  /* do lookup with the subdissector table */
  if (!dissector_try_uint(subdissector_table, chdlc_type, next_tvb, pinfo, tree)) {
    col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "0x%04x", chdlc_type);
    call_dissector(data_handle,next_tvb, pinfo, tree);
  }
}

/* Code to actually dissect the packets */
static void
dissect_macmgmt (tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
{

  const guint8 *src, *dst;
  guint16 msg_len;
  proto_item *mgt_hdr_it;
  proto_tree *mgt_hdr_tree;
  tvbuff_t *payload_tvb;
  guint8 type;
  col_set_str (pinfo->cinfo, COL_PROTOCOL, "DOCSIS MGMT");

  col_clear(pinfo->cinfo, COL_INFO);


  src = tvb_get_ptr (tvb, 6, 6);
  dst = tvb_get_ptr (tvb, 0, 6);
  SET_ADDRESS (&pinfo->dl_src, AT_ETHER, 6, src);
  SET_ADDRESS (&pinfo->src, AT_ETHER, 6, src);
  SET_ADDRESS (&pinfo->dl_dst, AT_ETHER, 6, dst);
  SET_ADDRESS (&pinfo->dst, AT_ETHER, 6, dst);

  if (tree)
    {
      mgt_hdr_it =
        proto_tree_add_protocol_format (tree, proto_docsis_mgmt, tvb, 0, 20,
                                        "Mac Management");
      mgt_hdr_tree = proto_item_add_subtree (mgt_hdr_it, ett_docsis_mgmt);
      proto_tree_add_item (mgt_hdr_tree, hf_docsis_mgt_dst_addr, tvb, 0, 6,
                           ENC_NA);
      proto_tree_add_item (mgt_hdr_tree, hf_docsis_mgt_src_addr, tvb, 6, 6,
                           ENC_NA);
      proto_tree_add_item (mgt_hdr_tree, hf_docsis_mgt_msg_len, tvb, 12, 2,
                           ENC_BIG_ENDIAN);
      proto_tree_add_item (mgt_hdr_tree, hf_docsis_mgt_dsap, tvb, 14, 1,
                           ENC_BIG_ENDIAN);
      proto_tree_add_item (mgt_hdr_tree, hf_docsis_mgt_ssap, tvb, 15, 1,
                           ENC_BIG_ENDIAN);
      proto_tree_add_item (mgt_hdr_tree, hf_docsis_mgt_control, tvb, 16, 1,
                           ENC_BIG_ENDIAN);
      proto_tree_add_item (mgt_hdr_tree, hf_docsis_mgt_version, tvb, 17, 1,
                           ENC_BIG_ENDIAN);
      proto_tree_add_item (mgt_hdr_tree, hf_docsis_mgt_type, tvb, 18, 1,
                           ENC_BIG_ENDIAN);
      proto_tree_add_item (mgt_hdr_tree, hf_docsis_mgt_rsvd, tvb, 19, 1,
                           ENC_BIG_ENDIAN);

    }
  /* Code to Call subdissector */
  /* sub-dissectors are based on the type field */
  type = tvb_get_guint8 (tvb, 18);
  msg_len = tvb_get_ntohs (tvb, 12);
  payload_tvb = tvb_new_subset (tvb, 20, msg_len - 6, msg_len - 6);

  if (dissector_try_uint
      (docsis_mgmt_dissector_table, type, payload_tvb, pinfo, tree))
    return;
  else
    call_dissector (data_handle, payload_tvb, pinfo, tree);
}

static void
dissect_ap1394(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
  proto_item *ti;
  proto_tree *fh_tree = NULL;
  guint16    etype;
  tvbuff_t *next_tvb;

  col_set_str(pinfo->cinfo, COL_PROTOCOL, "IP/IEEE1394");
  col_clear(pinfo->cinfo, COL_INFO);

  set_address_tvb(&pinfo->dl_src,   AT_EUI64, 8, tvb, 8);
  copy_address_shallow(&pinfo->src, &pinfo->dl_src);
  set_address_tvb(&pinfo->dl_dst,   AT_EUI64, 8, tvb, 0);
  copy_address_shallow(&pinfo->dst, &pinfo->dl_dst);

  if (tree) {
    ti = proto_tree_add_protocol_format(tree, proto_ap1394, tvb, 0, 18,
                "Apple IP-over-IEEE 1394, Src: %s, Dst: %s",
                address_to_str(wmem_packet_scope(), &pinfo->src), address_to_str(wmem_packet_scope(), &pinfo->dst));
    fh_tree = proto_item_add_subtree(ti, ett_ap1394);
    proto_tree_add_item(fh_tree, hf_ap1394_dst, tvb, 0, 8, ENC_NA);
    proto_tree_add_item(fh_tree, hf_ap1394_src, tvb, 8, 8, ENC_NA);
  }
  etype = tvb_get_ntohs(tvb, 16);
  proto_tree_add_uint(fh_tree, hf_ap1394_type, tvb, 16, 2, etype);
  next_tvb = tvb_new_subset_remaining(tvb, 18);
  if (!dissector_try_uint(ethertype_subdissector_table, etype, next_tvb,
                pinfo, tree))
    call_dissector(data_handle, next_tvb, pinfo, tree);
}

/*
 * Apparently 3Com had some scheme for encapsulating XNS in 802.2 LLC,
 * using a DSAP and SSAP of 0x80, and putting a 2-byte field that appeared
 * to contain, at least for IPP, the Ethertype value for IPP.
 *
 * We assume that the value there is an Ethertype value, except for
 * the Retix spanning tree protocol, which also uses a DSAP and SSAP
 * of 0x80 but has, at least in one capture, 0x0004 as the type
 * field.  We handle that specially.
 *
 * XXX - I've also seen packets on 802.11 with a DSAP and SSAP of 0x80,
 * but with random stuff that appears neither to be XNS nor Retix
 * spanning tree.
 */
static void
dissect_3com_xns(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
	proto_tree *subtree;
	proto_tree *ti;
	guint16 type;
	tvbuff_t *next_tvb;

	col_set_str(pinfo->cinfo, COL_PROTOCOL, "3Com XNS");
	col_clear(pinfo->cinfo, COL_INFO);

	ti = proto_tree_add_item(tree, proto_3com_xns, tvb, 0, 4, ENC_NA);
	subtree = proto_item_add_subtree(ti, ett_3com_xns);

	type = tvb_get_ntohs(tvb, 0);
	next_tvb = tvb_new_subset_remaining(tvb, 2);
	if (type == 0x0004) {
		proto_tree_add_uint(subtree, hf_3com_xns_type_retix_bpdu,
		    tvb, 0, 2, type);
		call_dissector(retix_bpdu_handle, next_tvb, pinfo, tree);
	} else {
		proto_tree_add_uint(subtree, hf_3com_xns_type_ethertype,
		    tvb, 0, 2, type);
		if (!dissector_try_uint(ethertype_subdissector_table,
		    type, next_tvb, pinfo, tree))
			call_dissector(data_handle, next_tvb, pinfo, tree);
	}
}

static void
dissect_mpeg_sect(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
    gint     offset           = 0;
    guint    section_length   = 0;
    gboolean syntax_indicator = FALSE;
    guint8   table_id;

    proto_item *ti;
    proto_tree *mpeg_sect_tree;

    table_id = tvb_get_guint8(tvb, offset);

    /* Check if a dissector can parse the current table */
    if (dissector_try_uint(mpeg_sect_tid_dissector_table, table_id, tvb, pinfo, tree))
        return;

    /* If no dissector is registered, use the common one */
    col_set_str(pinfo->cinfo, COL_PROTOCOL, "MPEG SECT");
    col_add_fstr(pinfo->cinfo, COL_INFO, "Table ID 0x%02x", table_id);

    ti = proto_tree_add_item(tree, proto_mpeg_sect, tvb, offset, -1, ENC_NA);
    mpeg_sect_tree = proto_item_add_subtree(ti, ett_mpeg_sect);

    proto_item_append_text(ti, " Table_ID=0x%02x", table_id);

    packet_mpeg_sect_header(tvb, offset, mpeg_sect_tree,
                &section_length, &syntax_indicator);

    if (syntax_indicator)
        packet_mpeg_sect_crc(tvb, pinfo, mpeg_sect_tree, 0, (section_length-1));
}

static void
dissect_ap1394(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
  proto_item *ti;
  proto_tree *fh_tree = NULL;
  const guint8 *src_addr, *dst_addr;
  guint16    etype;
  tvbuff_t *next_tvb;

  col_set_str(pinfo->cinfo, COL_PROTOCOL, "IP/IEEE1394");
  col_clear(pinfo->cinfo, COL_INFO);

  src_addr=tvb_get_ptr(tvb, 8, 8);
  SET_ADDRESS(&pinfo->dl_src,	AT_EUI64, 8, src_addr);
  SET_ADDRESS(&pinfo->src,	AT_EUI64, 8, src_addr);
  dst_addr=tvb_get_ptr(tvb, 0, 8);
  SET_ADDRESS(&pinfo->dl_dst,	AT_EUI64, 8, dst_addr);
  SET_ADDRESS(&pinfo->dst,	AT_EUI64, 8, dst_addr);

  if (tree) {
    ti = proto_tree_add_protocol_format(tree, proto_ap1394, tvb, 0, 18,
		"Apple IP-over-IEEE 1394, Src: %s, Dst: %s",
		bytes_to_ep_str(src_addr, 8), bytes_to_ep_str(dst_addr, 8));
    fh_tree = proto_item_add_subtree(ti, ett_ap1394);
    proto_tree_add_bytes(fh_tree, hf_ap1394_dst, tvb, 0, 8, dst_addr);
    proto_tree_add_bytes(fh_tree, hf_ap1394_src, tvb, 8, 8, src_addr);
  }
  etype = tvb_get_ntohs(tvb, 16);
  if (tree)
    proto_tree_add_uint(fh_tree, hf_ap1394_type, tvb, 16, 2, etype);
  next_tvb = tvb_new_subset_remaining(tvb, 18);
  if (!dissector_try_uint(ethertype_subdissector_table, etype, next_tvb,
		pinfo, tree))
    call_dissector(data_handle, next_tvb, pinfo, tree);
}

/* Code to actually dissect the packets */
static  void
dissect_hsr_frame(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
    proto_item *ti;
    proto_tree *hsr_tree;
    tvbuff_t *next_tvb;
    guint16 etype;
    guint16 lsdu_size, lsdu_size_correct;

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "HSR");

    col_set_str(pinfo->cinfo, COL_INFO, "HSR-Data Frame");

    /* create display subtree for the protocol */

    ti = proto_tree_add_item(tree, proto_hsr, tvb, 0, HSR_TOTAL_LENGTH, ENC_NA);

    hsr_tree = proto_item_add_subtree(ti, ett_hsr_frame);

    proto_tree_add_item(hsr_tree, hf_hsr_path,
                        tvb, HSR_PATH_OFFSET, HSR_LSDU_PATH_LENGTH , ENC_BIG_ENDIAN);

    proto_tree_add_item(hsr_tree, hf_hsr_netid,
                        tvb, HSR_PATH_OFFSET, HSR_LSDU_PATH_LENGTH , ENC_BIG_ENDIAN);

    proto_tree_add_item(hsr_tree, hf_hsr_laneid,
                        tvb, HSR_PATH_OFFSET, HSR_LSDU_PATH_LENGTH , ENC_BIG_ENDIAN);


    lsdu_size = tvb_get_ntohs(tvb, HSR_PATH_OFFSET) & 0x0fff;
    lsdu_size_correct = tvb_reported_length_remaining(tvb, 0);
    if (lsdu_size == lsdu_size_correct) {
        proto_tree_add_uint_format(hsr_tree, hf_hsr_lsdu_size,
                                   tvb, HSR_PATH_OFFSET, HSR_LSDU_PATH_LENGTH, lsdu_size,
                                   "LSDU size: %d [correct]", lsdu_size);
    } else {
        proto_tree_add_uint_format(hsr_tree, hf_hsr_lsdu_size,
                                   tvb, HSR_PATH_OFFSET, HSR_LSDU_PATH_LENGTH, lsdu_size,
                                   "LSDU size: %d [WRONG, should be %d]", lsdu_size, lsdu_size_correct);
    }

    proto_tree_add_item(hsr_tree, hf_hsr_sequence_nr,
                        tvb, HSR_SEQUENZNR_OFFSET,HSR_SEQUENZNR_LENGTH, ENC_BIG_ENDIAN);

    proto_tree_add_item(hsr_tree, hf_type,
                        tvb, HSR_TOTAL_LENGTH,2, ENC_BIG_ENDIAN);

    next_tvb = tvb_new_subset (tvb, HSR_TOTAL_LENGTH + 2, -1, -1);

    etype = tvb_get_ntohs(tvb, HSR_TOTAL_LENGTH);

    if (!dissector_try_uint(ethertype_subdissector_table, etype, next_tvb, pinfo, tree))
        call_dissector(data_handle, next_tvb, pinfo, hsr_tree);

}

static void
decode_teredo_ports(tvbuff_t *tvb, int offset, packet_info *pinfo,proto_tree *tree, int th_header)
{
	tvbuff_t *next_tvb;

	next_tvb = tvb_new_subset_remaining(tvb, offset);

	if (dissector_try_uint(teredo_dissector_table, th_header, next_tvb, pinfo, tree))
		return;

	call_dissector(data_handle,next_tvb, pinfo, tree);
}

static int
dissect_ppcap_payload_data(tvbuff_t *tvb, packet_info *pinfo, proto_tree * ppcap_tree1, int offset, proto_tree *tree, payload_type_type payload_type)
{
	tvbuff_t        *next_tvb;
	guint16 msg_len;
	msg_len = tvb_get_ntohs(tvb, offset);
	proto_tree_add_item( ppcap_tree1, hf_ppcap_length, tvb, offset, 2, ENC_BIG_ENDIAN);
	offset  = offset + 2;
	proto_tree_add_item(ppcap_tree1, hf_ppcap_payload_data, tvb, offset, msg_len, ENC_NA);

	if (msg_len%4)
		msg_len = msg_len +( 4- (msg_len%4));

	next_tvb = tvb_new_subset_remaining(tvb, offset);

	switch (payload_type) {
	case PPCAP_MTP3:
		call_dissector(mtp3_handle, next_tvb, pinfo, tree);  /* calling the MTP3 handle */
		break;
	case PPCAP_TCAP:
		/*
		 * The protocol which runs on TCAP takes the SSN value from the SCCP layer which is missing in this case.
		 * So we have made code changes for TCAP handle as below for taking the SSN value from ppcap.
		 */
		if (ssn != INVALID_SSN && dissector_try_uint(sccp_ssn_dissector_table, ssn, next_tvb, pinfo, tree))	{
			return  offset+msg_len;
		}else{
			call_dissector(tcap_handle, next_tvb, pinfo, tree);  /* calling the TCAP handle */
		}
		break;
	case PPCAP_BSSAP:
		call_dissector(bssap_handle, next_tvb, pinfo, tree);  /* calling the BSSAP handle */
		break;
	case PPCAP_RANAP:
		call_dissector(ranap_handle, next_tvb, pinfo, tree);  /* calling the RANAP handle */
		break;
	case PPCAP_H248:
		call_dissector(h248_handle, next_tvb, pinfo, tree);   /* calling the H248 handle */
		break;
	case PPCAP_SIP:
		call_dissector(sip_handle, next_tvb, pinfo, tree);    /* calling the SIP handle */
		break;
	case PPCAP_SCCP:
		call_dissector(sccp_handle, next_tvb, pinfo, tree);   /* calling the SCCP handle */
		break;
	default:
		call_dissector(data_handle, next_tvb, pinfo, tree);   /* calling the DATA handle */
		break;
	}

	offset += msg_len;
	return offset;
}

static int
dissect_vxlan_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int is_gpe)
{
    proto_tree *vxlan_tree;
    proto_item *ti;
    tvbuff_t *next_tvb;
    int offset = 0;
    guint32 vxlan_next_proto;

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


    ti = proto_tree_add_item(tree, proto_vxlan, tvb, offset, 8, ENC_NA);
    vxlan_tree = proto_item_add_subtree(ti, ett_vxlan);

    if(is_gpe) {
        proto_tree_add_bitmask(vxlan_tree, tvb, offset, hf_vxlan_gpe_flags, ett_vxlan_flags, gpe_flags_fields, ENC_BIG_ENDIAN);
        offset += 1;

        proto_tree_add_item(vxlan_tree, hf_vxlan_gpe_reserved_16, tvb, offset, 2, ENC_BIG_ENDIAN);
        offset += 2;

        proto_tree_add_item_ret_uint(vxlan_tree, hf_vxlan_next_proto, tvb, offset, 1, ENC_BIG_ENDIAN, &vxlan_next_proto);
        offset += 1;
    } else {
        proto_tree_add_bitmask(vxlan_tree, tvb, offset, hf_vxlan_flags, ett_vxlan_flags, flags_fields, ENC_BIG_ENDIAN);
        offset += 2;

        proto_tree_add_item(vxlan_tree, hf_vxlan_gbp, tvb, offset, 2, ENC_BIG_ENDIAN);
        offset += 2;
    }

    proto_tree_add_item(vxlan_tree, hf_vxlan_vni, tvb, offset, 3, ENC_BIG_ENDIAN);
    offset += 3;

    proto_tree_add_item(vxlan_tree, hf_vxlan_reserved_8, tvb, offset, 1, ENC_BIG_ENDIAN);
    offset += 1;

    next_tvb = tvb_new_subset_remaining(tvb, offset);

    if(is_gpe){
        if(!dissector_try_uint(vxlan_dissector_table, vxlan_next_proto, next_tvb, pinfo, tree)) {
            call_data_dissector(next_tvb, pinfo, vxlan_tree);
        }
    } else {
        call_dissector(eth_handle, next_tvb, pinfo, tree);
    }

    return tvb_captured_length(tvb);
}

static void dissect_osi(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
  guint8    nlpid;
  tvbuff_t *new_tvb;

  pinfo->current_proto = "OSI";

  nlpid = tvb_get_guint8(tvb, 0);

  /* try lookup with the subdissector tables that includes the nlpid */
  if (dissector_try_uint(osinl_incl_subdissector_table, nlpid, tvb, pinfo, tree))
    return;
  /* try lookup with the subdissector tables that excludes the nlpid */
  new_tvb = tvb_new_subset_remaining(tvb, 1);
  if (dissector_try_uint(osinl_excl_subdissector_table, nlpid, new_tvb, pinfo, tree))
    return;

  switch (nlpid) {

    /* ESIS (X.25) is not currently decoded */

    case NLPID_ISO9542X25_ESIS:
      col_set_str(pinfo->cinfo, COL_PROTOCOL, "ESIS (X.25)");
      call_dissector(data_handle,tvb, pinfo, tree);
      break;
    case NLPID_ISO10747_IDRP:
      col_set_str(pinfo->cinfo, COL_PROTOCOL, "IDRP");
      call_dissector(data_handle,tvb, pinfo, tree);
      break;
    default:
      col_set_str(pinfo->cinfo, COL_PROTOCOL, "ISO");
      col_add_fstr(pinfo->cinfo, COL_INFO, "Unknown ISO protocol (%02x)", nlpid);

      call_dissector(data_handle,tvb, pinfo, tree);
      break;
  }
} /* dissect_osi */

static void
dissect_ayiya(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
	proto_tree *ayiya_tree;
	int offset = 0;
	int idlen, siglen, ayiya_len;
	guint8 next_header, opcode;
	tvbuff_t *payload;

	idlen = 1 << tvb_get_bits8(tvb, 0, 4);
	siglen = tvb_get_bits8(tvb, 8, 4) * 4;
	opcode = tvb_get_bits8(tvb, 20, 4);
	next_header = tvb_get_guint8(tvb, 3);

	ayiya_len = 8+idlen+siglen;

	col_set_str(pinfo->cinfo, COL_PROTOCOL, "AYIYA");

	if (tree) {
		proto_item *ti;
		nstime_t tv;
		ti = proto_tree_add_protocol_format( tree, proto_ayiya, tvb,
											 offset, ayiya_len, "AYIYA" );
		ayiya_tree = proto_item_add_subtree(ti, ett_ayiya);

		proto_tree_add_bits_item(ayiya_tree, hf_id_len, tvb, 0, 4, ENC_BIG_ENDIAN);
		proto_tree_add_bits_item(ayiya_tree, hf_id_type, tvb, 4, 4, ENC_BIG_ENDIAN);
		proto_tree_add_bits_item(ayiya_tree, hf_sig_len, tvb, 8, 4, ENC_BIG_ENDIAN);
		proto_tree_add_bits_item(ayiya_tree, hf_hash_method, tvb, 12, 4, ENC_BIG_ENDIAN);
		proto_tree_add_bits_item(ayiya_tree, hf_auth_method, tvb, 16, 4, ENC_BIG_ENDIAN);
		proto_tree_add_bits_item(ayiya_tree, hf_opcode, tvb, 20, 4, ENC_BIG_ENDIAN);
		proto_tree_add_uint_format(ayiya_tree, hf_next_header, tvb,
								   3, 1, next_header,
								   "Next header: %s (0x%02x)",
								   ipprotostr(next_header), next_header);
		tv.secs = tvb_get_ntohl(tvb, 4);
		tv.nsecs = 0;
		proto_tree_add_time(ayiya_tree, hf_epoch, tvb, 4, 4, &tv);
		proto_tree_add_item(ayiya_tree, hf_identity, tvb, 8, idlen, ENC_NA);
		proto_tree_add_item(ayiya_tree, hf_signature, tvb, 8+idlen, siglen, ENC_NA);
	}
	offset = ayiya_len;
	switch (opcode) {
	case OPCODE_FORWARD:
		payload = tvb_new_subset_remaining(tvb, offset);
		dissector_try_uint(ip_dissector_table, next_header, payload, pinfo, tree);
		break;
	}
}