plugins-wimax-msg_rng_rsp.c

Intel的WIMAX代码,主要是mac层code

			FT_FLOAT, BASE_DEC, NULL, 0x00, "", HFILL
		}
	},
	{
		&hf_rng_rsp_ul_channel_id,
		{
			"Uplink Channel ID", "wimax.rng_rsp.ul_chan_id",
			FT_UINT8, BASE_DEC, NULL, 0x00, "", HFILL
		}
	},
	{
		&hf_rng_rsp_ul_chan_id_override,
		{
			"Uplink channel ID Override", "wimax.rng_rsp.ul_chan_id_override",
			FT_UINT8, BASE_DEC, NULL, 0x00, "", HFILL
		}
	},
	{
		&hf_tlv_type,
		{
			"Unknown TLV Type", "wimax.rng_rsp.unknown_tlv_type",
			FT_BYTES, BASE_NONE, NULL, 0x00, "", HFILL
		}
	},
	{
		&hf_tlv_value,
		{
			"Value", "wimax.rng_rsp.tlv_value",
			FT_BYTES, BASE_NONE, NULL, 0x00, "", HFILL
		}
	}
};

/* Register Wimax Mac Payload Protocol and Dissector */
void proto_register_mac_mgmt_msg_rng_rsp(void)
{
	if (proto_mac_mgmt_msg_rng_rsp_decoder == -1)
	{
		proto_mac_mgmt_msg_rng_rsp_decoder = proto_mac_mgmt_msg_rng_req_decoder;

		proto_register_field_array(proto_mac_mgmt_msg_rng_rsp_decoder, hf, array_length(hf));
		proto_register_subtree_array(ett, array_length(ett));
	}
}

/* Decode RNG-RSP messages. */
void dissect_mac_mgmt_msg_rng_rsp_decoder(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
        proto_item *ranging_status_item = NULL;
	proto_item *dl_freq_override_item = NULL;
        proto_item *ss_mac_address_item = NULL;
        proto_item *frame_number_item = NULL;
        proto_item *opportunity_number_item = NULL;

	guint offset = 0;
	guint tlv_offset;
	guint tvb_len, payload_type;
	proto_item *rng_rsp_item = NULL;
	proto_item *tlv_item = NULL;
	proto_tree *rng_rsp_tree = NULL;
	proto_tree *sub_tree = NULL;
	proto_tree *tlv_tree = NULL;
	tlv_info_t tlv_info;
	gint tlv_type;
	guint tlv_len;
	guint this_offset = 0;
	tlv_info_t sub_tlv_info;
	gint sub_tlv_type;
	gint sub_tlv_len;
	guint sub_tlv_offset;
	float timing_adjust;
	float power_level_adjust;
	gint offset_freq_adjust;

	/* Ensure the right payload type */
	payload_type = tvb_get_guint8(tvb, offset);
	if(payload_type != MAC_MGMT_MSG_RNG_RSP)
	{
		return;
	}

	if (tree)
	{	/* we are being asked for details */

		/* Get the tvb reported length */
		tvb_len =  tvb_reported_length(tvb);
		/* display MAC payload type RNG-RSP */
		rng_rsp_item = proto_tree_add_protocol_format(tree, proto_mac_mgmt_msg_rng_rsp_decoder, tvb, offset, tvb_len, "MAC Management Message, RNG-RSP (5)");
		/* add MAC RNG-RSP subtree */
		rng_rsp_tree = proto_item_add_subtree(rng_rsp_item, ett_mac_mgmt_msg_rng_rsp_decoder);
		/* display the Message Type */
		proto_tree_add_item(rng_rsp_tree, hf_rng_rsp_message_type, tvb, offset, 1, FALSE);
		proto_tree_add_item(rng_rsp_tree, hf_rng_req_reserved, tvb, 1, 1, FALSE);
		offset += 2;

		while(offset < tvb_len)
		{
			/* Get the TLV data. */
			init_tlv_info(&tlv_info, tvb, offset);
			/* get the TLV type */
			tlv_type = get_tlv_type(&tlv_info);
			/* get the TLV length */
			tlv_len = get_tlv_length(&tlv_info);
			if(tlv_type == -1 || tlv_len > MAX_TLV_LEN || tlv_len < 1)
			{	/* invalid tlv info */
				if(pinfo->cinfo)
				{
					col_append_sep_str(pinfo->cinfo, COL_INFO, NULL, "RNG-RSP TLV error");
				}
				proto_tree_add_item(rng_rsp_tree, hf_rng_invalid_tlv, tvb, offset, (tvb_len - offset), FALSE);
				break;
			}
			/* get the offset to the TLV data */
			tlv_offset = offset + get_tlv_value_offset(&tlv_info);

			switch (tlv_type) {
				case RNG_RSP_TIMING_ADJUST: {
					sub_tree = add_protocol_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, proto_mac_mgmt_msg_rng_rsp_decoder, tvb, tlv_offset, tlv_len, "Timing Adjust (%u byte(s))", tlv_len);
					timing_adjust = (float)(gint32)tvb_get_ntohl(tvb, tlv_offset) / 4;
					tlv_item = proto_tree_add_float_format_value(sub_tree, hf_rng_rsp_timing_adjust, tvb,
						tlv_offset, 4, timing_adjust, " %.2f modulation symbols", timing_adjust);
					if ((timing_adjust < -2) || (timing_adjust > 2))
						proto_item_append_text(tlv_item, " (during periodic ranging shall not exceed +- 2)");
					break;
				}
				case RNG_RSP_POWER_LEVEL_ADJUST: {
					sub_tree = add_protocol_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, proto_mac_mgmt_msg_rng_rsp_decoder, tvb, tlv_offset, tlv_len, "Power Level Adjust (%u byte(s))", tlv_len);
					power_level_adjust = (float)(gint8)tvb_get_guint8(tvb, tlv_offset) / 4;
					proto_tree_add_float_format_value(sub_tree, hf_rng_rsp_power_level_adjust, tvb, tlv_offset, 1,
								power_level_adjust, " %.2f dB", power_level_adjust);
					break;
				}
				case RNG_RSP_OFFSET_FREQ_ADJUST: {
					sub_tree = add_protocol_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, proto_mac_mgmt_msg_rng_rsp_decoder, tvb, tlv_offset, tlv_len, "Offset Frequency Adjust (%u byte(s))", tlv_len);
					offset_freq_adjust = tvb_get_ntohl(tvb, tlv_offset);
					proto_tree_add_int_format_value(sub_tree, hf_rng_rsp_offset_freq_adjust, tvb, tlv_offset, 4,
						offset_freq_adjust, " %d Hz", offset_freq_adjust);
					break;
				}
				case RNG_RSP_RANGING_STATUS:
					sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_rsp_ranging_status, tvb, tlv_offset, 1, FALSE);
					ranging_status_item = proto_tree_add_item(sub_tree, hf_rng_rsp_ranging_status, tvb, tlv_offset, 1, FALSE);
					break;
				case RNG_RSP_DL_FREQ_OVERRIDE: {
					sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_rsp_dl_freq_override, tvb, tlv_offset, 4, FALSE);
					dl_freq_override_item = proto_tree_add_item(sub_tree, hf_rng_rsp_dl_freq_override, tvb, tlv_offset, 4, FALSE);
					proto_item_append_text(dl_freq_override_item, " kHz");
					break;
				}
				case RNG_RSP_UL_CHANNEL_ID_OVERRIDE:
					sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_rsp_ul_chan_id_override, tvb, tlv_offset, 1, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_ul_chan_id_override, tvb, tlv_offset, 1, FALSE);
					break;
				case RNG_RSP_DL_OPERATIONAL_BURST_PROFILE:
					sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_rsp_dl_operational_burst_profile, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_dl_operational_burst_profile_diuc, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_dl_operational_burst_profile_ccc, tvb, tlv_offset, 2, FALSE);
					break;
				case RNG_RSP_SS_MAC_ADDRESS:
					if (tlv_len == 6)
					{
						sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_rsp_ss_mac_address, tvb, tlv_offset, 6, FALSE);
						ss_mac_address_item = proto_tree_add_item(sub_tree, hf_rng_rsp_ss_mac_address, tvb, tlv_offset, 6, FALSE);
					} else {
						sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_invalid_tlv, tvb, tlv_offset, tlv_len, FALSE);
						proto_tree_add_item(sub_tree, hf_rng_rsp_ss_mac_address, tvb, tlv_offset, 6, FALSE);
					}
					break;
				case RNG_RSP_BASIC_CID:
					sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_rsp_basic_cid, tvb, tlv_offset, 1, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_basic_cid, tvb, tlv_offset, 2, FALSE);
					break;
				case RNG_RSP_PRIMARY_MGMT_CID:
					sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_rsp_primary_mgmt_cid, tvb, tlv_offset, 1, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_primary_mgmt_cid, tvb, tlv_offset, 2, FALSE);
					break;
				case RNG_RSP_AAS_BROADCAST_PERMISSION:
					sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_rsp_broadcast, tvb, tlv_offset, 1, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_broadcast, tvb, tlv_offset, 1, FALSE);
					break;
				case RNG_RSP_FRAME_NUMBER:
					sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_rsp_frame_number, tvb, tlv_offset, 3, FALSE);
					frame_number_item = proto_tree_add_item(sub_tree, hf_rng_rsp_frame_number, tvb, tlv_offset, 3, FALSE);
					break;
				case RNG_RSP_OPPORTUNITY_NUMBER:
					sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_rsp_opportunity_number, tvb, tlv_offset, 1, FALSE);
					opportunity_number_item = proto_tree_add_item(sub_tree, hf_rng_rsp_opportunity_number, tvb, tlv_offset, 1, FALSE);
					if (tvb_get_ntohl(tvb, tlv_offset) == 0)
						proto_item_append_text(opportunity_number_item, " (may not be 0!)");
					break;
				case RNG_RSP_SERVICE_LEVEL_PREDICTION:
					sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_rsp_service_level_prediction, tvb, tlv_offset, 1, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_service_level_prediction, tvb, tlv_offset, 1, FALSE);
					break;
				case RNG_RSP_RESOURCE_RETAIN_FLAG:
					sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_rsp_resource_retain_flag, tvb, tlv_offset, 1, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_resource_retain_flag, tvb, tlv_offset, 1, FALSE);
					break;
				case RNG_RSP_HO_PROCESS_OPTIMIZATION:
					sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_rsp_ho_process_optimization, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_ho_process_optimization_0, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_ho_process_optimization_1_2, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_ho_process_optimization_3, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_ho_process_optimization_4, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_ho_process_optimization_5, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_ho_process_optimization_6, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_ho_process_optimization_7, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_ho_process_optimization_8, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_ho_process_optimization_9, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_ho_process_optimization_10, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_ho_process_optimization_11, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_ho_process_optimization_12, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_ho_process_optimization_13, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_ho_process_optimization_14, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_ho_process_optimization_15, tvb, tlv_offset, 2, FALSE);
					break;
				case RNG_RSP_SBC_RSP_ENCODINGS:
					sub_tree = add_protocol_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, proto_mac_mgmt_msg_rng_rsp_decoder, tvb, tlv_offset, tlv_len, "SBC-RSP Encodings (%u byte(s))", tlv_len);
					dissect_mac_mgmt_msg_sbc_rsp_decoder(tvb_new_subset(tvb, tlv_offset, tlv_len, tlv_len), pinfo, sub_tree);
					break;
				case RNG_RSP_REG_RSP_ENCODINGS:
					sub_tree = add_protocol_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, proto_mac_mgmt_msg_rng_rsp_decoder, tvb, tlv_offset, tlv_len, "REG-RSP Encodings (%u byte(s))", tlv_len);
					dissect_mac_mgmt_msg_reg_rsp_decoder(tvb_new_subset(tvb, tlv_offset, tlv_len, tlv_len), pinfo, sub_tree);
					break;
				/* Implemented message encoding 33 (Table 367 in IEEE 802.16e-2007) */
				case RNG_RSP_DL_OP_BURST_PROFILE_OFDMA:
					sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_rsp_dl_op_burst_profile_ofdma, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_least_robust_diuc, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_repetition_coding_indication, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_config_change_count_of_dcd, tvb, tlv_offset, 2, FALSE);
					break;
				case RNG_RSP_HO_ID:
					sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_rsp_ho_id, tvb, tlv_offset, 1, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_ho_id, tvb, tlv_offset, 1, FALSE);
					break;
				case RNG_RSP_LOCATION_UPDATE_RESPONSE:
					sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_rsp_location_update_response, tvb, tlv_offset, 1, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_location_update_response, tvb, tlv_offset, 1, FALSE);
					break;
				case RNG_RSP_PAGING_INFORMATION:
					sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_rsp_paging_information, tvb, tlv_offset, 5, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_paging_cycle, tvb, tlv_offset, 2, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_paging_offset, tvb, tlv_offset+2, 1, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_paging_group_id, tvb, tlv_offset+3, 2, FALSE);
					break;
				case RNG_RSP_POWER_SAVING_CLASS_PARAMETERS:
					sub_tree = add_protocol_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, proto_mac_mgmt_msg_rng_rsp_decoder, tvb, tlv_offset, tlv_len, "Power Saving Class Parameters (%u byte(s))", tlv_len);
					dissect_power_saving_class(sub_tree, tlv_type, tvb, tlv_len, pinfo, tlv_offset);
					break;
				case RNG_RSP_SA_CHALLENGE_TUPLE:
					/* Display SA Challenge Tuple header */
					sub_tree = add_protocol_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, proto_mac_mgmt_msg_rng_rsp_decoder, tvb, tlv_offset, tlv_len, "SA Challenge Tuple (%u byte(s))", tlv_len);
					/* add subtree */
					/* Use a local copy of tlv_offset */
					this_offset = tlv_offset;
					while(this_offset < tlv_len) {
						/* Get the sub TLV data. */
						init_tlv_info(&sub_tlv_info, tvb, this_offset);
						/* get the sub TLV type */
						sub_tlv_type = get_tlv_type(&sub_tlv_info);
						/* get the TLV length */
						sub_tlv_len = get_tlv_length(&sub_tlv_info);
						if(tlv_type == -1 || sub_tlv_len > MAX_TLV_LEN || sub_tlv_len < 1)
						{	/* invalid tlv info */
							if(pinfo->cinfo)
							{
								col_append_sep_str(pinfo->cinfo, COL_INFO, NULL, "RNG-RSP TLV error");
							}
							proto_tree_add_item(rng_rsp_tree, hf_rng_invalid_tlv, tvb, tlv_offset, (tvb_len - offset), FALSE);
							break;
						}
						/* get the offset to the sub TLV data */
						sub_tlv_offset = this_offset + get_tlv_value_offset(&sub_tlv_info);
						switch (sub_tlv_type) {
							case RNG_RSP_SA_CHALLENGE_BS_RANDOM:
								tlv_tree = add_tlv_subtree(&sub_tlv_info, ett_rng_rsp_message_tree, sub_tree, hf_rng_rsp_bs_random, tvb, sub_tlv_offset, sub_tlv_len, FALSE);
								proto_tree_add_item(tlv_tree, hf_rng_rsp_bs_random, tvb, sub_tlv_offset, sub_tlv_len, FALSE);
								break;
							case RNG_RSP_SA_CHALLENGE_AKID:
								tlv_tree = add_tlv_subtree(&sub_tlv_info, ett_rng_rsp_message_tree, sub_tree, hf_rng_rsp_akid, tvb, sub_tlv_offset, sub_tlv_len, FALSE);
								proto_tree_add_item(tlv_tree, hf_rng_rsp_akid, tvb, sub_tlv_offset, sub_tlv_len, FALSE);
								break;
							default:
								tlv_tree = add_tlv_subtree(&sub_tlv_info, ett_rng_rsp_message_tree, sub_tree, hf_tlv_type, tvb, sub_tlv_offset, sub_tlv_len, FALSE);
								proto_tree_add_item(tlv_tree, hf_tlv_type, tvb, sub_tlv_offset, sub_tlv_len, FALSE);
								break;
						}
						this_offset = sub_tlv_len + sub_tlv_offset;
					}
					break;
				case DSx_UPLINK_FLOW:
					/* display Uplink Service Flow Encodings info */
					/* add subtree */
					sub_tree = add_protocol_subtree(&tlv_info, ett_mac_mgmt_msg_rng_rsp_decoder, rng_rsp_tree, proto_mac_mgmt_msg_rng_rsp_decoder, tvb, tlv_offset, tlv_len, "Uplink QOS Parameters (%u bytes)", tlv_len);
					/* decode and display the DL Service Flow Encodings */
					wimax_service_flow_encodings_decoder(tvb_new_subset(tvb, tlv_offset, tlv_len, tlv_len), pinfo, sub_tree);
					break;
				case DSx_DOWNLINK_FLOW:
					/* display Downlink Service Flow Encodings info */
					/* add subtree */
					sub_tree = add_protocol_subtree(&tlv_info, ett_mac_mgmt_msg_rng_rsp_decoder, rng_rsp_tree, proto_mac_mgmt_msg_rng_rsp_decoder, tvb, tlv_offset, tlv_len, "Downlink QOS Parameters (%u bytes)", tlv_len);
					/* decode and display the DL Service Flow Encodings */
					wimax_service_flow_encodings_decoder(tvb_new_subset(tvb, tlv_offset, tlv_len, tlv_len), pinfo, sub_tree);
					break;
				case RNG_RSP_RANGING_CODE_ATTRIBUTES:
				/* case SHORT_HMAC_TUPLE: */
					sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_rng_rsp_ranging_subchan, tvb, tlv_offset, 4, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_time_symbol_reference, tvb, tlv_offset, 4, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_subchannel_reference, tvb, tlv_offset, 4, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_ranging_code_index, tvb, tlv_offset, 4, FALSE);
					proto_tree_add_item(sub_tree, hf_rng_rsp_frame_number2, tvb, tlv_offset, 4, FALSE);
					break;
				case SHORT_HMAC_TUPLE_COR2:
					if (include_cor2_changes) {
						sub_tree = add_protocol_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, proto_mac_mgmt_msg_rng_rsp_decoder, tvb, tlv_offset, tlv_len, "Short HMAC Tuple (%u byte(s))", tlv_len);
						wimax_short_hmac_tuple_decoder(sub_tree, tvb, tlv_offset, tvb_len - offset);
					} else {
						/* Unknown TLV type */
						sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_tlv_type, tvb, tlv_offset, 1, FALSE);
						proto_tree_add_item(sub_tree, hf_tlv_type, tvb, tlv_offset, tlv_len, FALSE);
					}
					break;

				default:
					sub_tree = add_tlv_subtree(&tlv_info, ett_rng_rsp_message_tree, rng_rsp_tree, hf_tlv_type, tvb, tlv_offset, 1, FALSE);
					proto_tree_add_item(sub_tree, hf_tlv_type, tvb, tlv_offset, tlv_len, FALSE);
					break;

			}
			offset = tlv_len + tlv_offset;
		}	/* end of TLV process while loop */
		if (ranging_status_item && dl_freq_override_item)
			proto_item_append_text(ranging_status_item, " (shall be set to 2 because Downlink Frequency Override is present)");
		if (ss_mac_address_item && frame_number_item) {
			proto_item_append_text(frame_number_item, " (mutually exclusive with SS MAC Address!)");
			proto_item_append_text(ss_mac_address_item, " (mutually exclusive with Frame Number!)");
		}
		if (ss_mac_address_item && opportunity_number_item) {
			proto_item_append_text(opportunity_number_item, " (mutually exclusive with SS MAC Address!)");
			proto_item_append_text(ss_mac_address_item, " (mutually exclusive with Initial Ranging Opportunity Number!)");
		}
		if (!ranging_status_item)
			proto_item_append_text(rng_rsp_tree, " (Ranging status is missing!)");

	}
}




      取自 
      http://anonsvn.wireshark.org/wireshark/trunk 的 plugins/wimax/msg_rng_rsp.c 
      - LGPL - C