CN102158882B - Two-channel data detection and protocol analysis meter based on 6LowPAN and method - Google Patents

Abstract

The invention claims protection of a 6LowPAN-based two-channel data detection and protocol analyzer and method, and relates to the technical field of wireless sensor networks. The analyzer includes a wireless data acquisition module and an upper computer decoding analysis part, a wireless RF transceiver 1 and a wireless RF transceiver 2, and continuously monitors whether there is a wireless data message in the channel, and the main controller encapsulates the data message header and The channel number is uploaded to the upper computer; the upper computer data processing module determines the frame type according to the frame type subsection in the frame control domain of the MAC layer header of the received data message, if it is a 6LowPAN data packet, the 6LowPAN data packet The protocol header is analyzed layer by layer according to the protocol rules of the 6LowPAN protocol model, and the analysis and statistics are sent to the man-machine interface for display.

Description

A 6LowPAN-based two-channel data detection and protocol analyzer and method

technical field

The present invention relates to the technical field of wireless sensor networks, especially for data detection and protocol analysis of 6LowPAN (IPv6 over LR_WPAN, referred to as 6LowPAN) wireless sensor networks.

Background technique

With the rapid development of wireless communication technology in the field of industrial control, an industrial wireless communication technology for information interaction between devices has emerged. In the research and development and testing of wireless sensor technology, data detection and protocol analysis between devices in the wireless sensor network are required.

There are many communication network protocol analysis devices, mainly to analyze the protocol and provide specific data support for the reliability and stability of the network system. However, current protocol analyzers have many defects. First of all, the most commonly used one is the sniffer, which mainly monitors the network status and data flow, and it is a single channel monitoring, which lacks the detection of the wireless sensor network. Secondly, the existing protocols for wireless sensor networks are mainly for the detection and analysis of the single protocol ZigBee, which lacks scalability. Thirdly, the penetration of IPv6 technology in the wireless sensor network, the detection and analysis of the new wireless sensor network technology based on IEEE802.15.4 to achieve IPv6 communication 6LowPAN requires new data detection and protocol analysis to develop and research for 6LowPAN Provide reliable data support. Therefore, traditional analyzers cannot meet the needs of new technologies, and it is necessary to update data detection and protocol analysis technologies.

Contents of the invention

In order to solve the above-mentioned technical problems in the prior art, the present invention proposes a 6LowPAN-based two-channel data detection and protocol analyzer (hereinafter referred to as "analyzer"). The analyzer is a multifunction analyzer based on USB interface. The analyzer can self-configure two channels, simultaneously detect the wireless sensor network data message, and decode and analyze the protocol data message. Support compatible ZigBee protocol analysis and expandable detection and decoding analysis of WIA-PA and ISA100.11a messages.

This data detection and protocol analyzer includes two parts: the wireless data acquisition module part, and the upper computer decoding analysis part. The wireless data acquisition module is composed of a main controller, a 2.4GHz wireless radio frequency receiver module 1, a 2.4GHz wireless radio frequency receiver module 2, a USB interface module, and a power management module. The upper computer decoding and analysis part includes system setting module, data processing module and man-machine interface. The main controller performs bus operation through the two serial peripheral device interfaces of the synchronous serial port controller, and controls the wireless RF receiver 1 and the wireless RF receiver respectively. Transceiver 2, by constantly polling whether there is a wireless data message in the continuous monitoring channel, and storing the effective data message in the data cache of the respective wireless RF transceiver, the main controller encapsulates the header and the data message of the data message The channel number is uploaded to the host computer; the data analysis module of the decoding analysis part of the host computer decodes and analyzes the detected data packets, and after analyzing according to the protocol type, sends the analyzed data message to the data display module, and the system setting part downloads it through the serial port. Send commands to modify the channel for receiving data packets. Whether the polling continuous monitoring channel has a wireless data message specifically includes, polling and scanning the 16 original channel sequence tables through two radio frequency receivers, and when scanning each channel, when monitoring the maximum of each channel data If there is still no data message within the time value, it will automatically switch to the next adjacent channel number according to the original channel sequence table. Decoding and analyzing the detected data packets specifically includes that the data processing module of the upper computer determines the frame type according to the frame type subsection in the frame control field of the MAC layer header of the received data message. If the received MAC layer header is a MAC command frame and a beacon frame, the data packet is a WIA-PA or ZigBee data packet; if the header is a data frame, it is 6LowPAN, ISA100.11a, WIA-PA and one of the data packets in ZigBee, the protocol rules of the 6LowPAN protocol model are preferentially analyzed layer by layer.

The present invention also proposes a two-channel data detection and protocol analysis method based on 6LowPAN, which is characterized in that the main controller of the wireless data acquisition part performs bus operation through two serial peripheral device interfaces of the synchronous serial port controller, respectively Control the wireless RF receiver 1 and the wireless RF transceiver 2, by continuously polling whether there is a wireless data message in the continuous monitoring channel, and storing the valid data message in the data cache of the respective wireless RF transceiver, the main controller Encapsulate the header and channel number of the data message, and upload it to the host computer; the data analysis module of the host computer decoding and analysis part decodes and analyzes the detected data packet, parses it according to its protocol type, and sends the parsed data message to the data The display module and the system setting part send commands through the serial port to modify the channel for receiving data packets.

The protocol analyzer proposed by the present invention is independent of the wireless sensor network system, and can simultaneously perform two-channel data monitoring and protocol analysis, and can also adjust two channels to detect one channel at the same time, which reduces the packet loss rate and can be used for 6LowPAN Perform detection and protocol decoding analysis, and compatible with ZigBee protocol analysis and expandable WIA-PA, ISA100.11a protocol decoding analysis.

Description of drawings

Fig. 1 schematic block diagram of the present invention;

Fig. 2 partial principle structure diagram of wireless data acquisition module;

Figure 3 is a structural diagram of the upper computer decoding analysis part;

Fig. 4 work flow chart of the present invention;

Figure 5 Serial port data receiving flow chart;

Figure 6 6LowPAN analysis flow chart.

Labels in Figure 1: A is the main controller, B is the 2.4GHz wireless RF transceiver 1, C is the 2.4GHz wireless RF transceiver 2, D is the USB interface, and E is the decoding and analysis part of the upper computer.

Detailed ways

The technical scheme of the present invention will be further analyzed in detail below with reference to the accompanying drawings and specific examples.

Figure 1 shows the block diagram of the analyzer. It includes two parts: the wireless data acquisition module and the upper computer decoding analysis part. The wireless data acquisition part includes a main controller, a 2.4GHz wireless radio frequency transceiver 1, a 2.4GHz wireless radio frequency transceiver 2, a USB interface module, and a power management module. The upper computer decoding analysis part includes system setting module, data processing module and man-machine interface.

Figure 2 shows the schematic structure diagram of the wireless data acquisition module. The main controller adopts the newly released Cortex-M0 core of the microprocessor chip ARM Company, which is the smallest and lowest energy consumption ARM processor in the market. The wireless radio frequency receiver adopts the UZ2400 module. The UZ2400 module works in the 2.4GHz frequency band and has 16 channels. It is a radio frequency module that conforms to the IEEE802.15.4 standard protocol. At this time, the Cortex-M0 processor polls the data in the read buffer (FIFO) through the UZ2400 wireless RF receiver 1 and UZ2400 wireless RF receiver 2 respectively controlled by the serial peripheral interface (SPI0 and SPI1) bus. , the Cortex-M0 processor processes the data packets.

Set 2.4GHz radio frequency transceiver 1 and 2.4GHz radio frequency transceiver 2 to ensure simultaneous detection of two-channel data packets, support for working in the frequency band of 2.4GHz, distributed from 2.405GHz-2.480GHz, a total of 16 channels radio frequency receiver. The core of the wireless data acquisition module part of the main controller, the bus operation is performed through two serial peripheral interfaces (SPI) of the synchronous serial port controller (SSP), the main controller is the host mode, and the wireless radio frequency receiver is the slave mode to control the work of radio frequency transceivers 1 and 2 respectively. The main controller sets the registers of the wireless data module through the bus, continuously polls the two wireless radio frequency transceivers, and continuously monitors whether there are wireless data messages in the two channels.

The main controller realizes the communication between the wireless acquisition module and the upper computer through the serial port to USB. The power management module provides power to the entire analyzer through the serial port to USB interface circuit.

The wireless data message is stored in the data buffer (FIFO) of the wireless radio frequency receiver through baseband filtering, and the main controller reads the valid data message in the data buffer (FIFO) through the bus operation, and reads The received message is identified by the length of the message to check whether it is a complete data message. Send the complete message to the decoding and analysis part of the upper computer.

Figure 3 shows the structure diagram of the upper computer decoding and analysis part. The upper computer is composed of three parts: data processing module, system setting module and human-machine interface. It judges the received message and identifies the data message of the protocol. The data processing module decodes the data message of the protocol stack layer by layer. Analyze, obtain data message information such as source address, destination address, frame type, and load of each layer of the protocol stack data message, provide data graph display, and perform real-time or post-event monitoring and analysis on data messages, and provide detailed data , to provide reliable support for R&D and application.

As shown in Figure 4, it is the working flow diagram of two-channel data detection and protocol analyzer. Take the default two channels as 0x0B and 0x0C as an example to describe the channel switching process in detail. After power-on, initialize the main controller Cortex-M0 processor, and write the registers of the wireless radio frequency receiver 1 and 2 through the serial peripheral interface (SPI) of the Cortex-M0 processor to complete the data acquisition configuration . 16 raw channels (displayed as hexadecimal values from ch11 (0B) to ch26 (1A), 0B=11,0C=12...10=16,...19= 25,1A=26) The sequence table is polled and scanned. When scanning each channel, if there is still no data packet within the maximum time value (monitoring time threshold set by the system) of monitoring each channel data, it will automatically switch to the next adjacent channel according to the original channel sequence table 0x0B-0x1A No. 0x0D, 0x0E continue to monitor the air wireless data.

After the data message is filtered by the baseband of the wireless radio frequency receiver, it is sent to the receiving data buffer (RXFIFO), and the frame check sequence (FCS) checks the legality of the data message at the same time. There are two 144-byte (RXFIFO_0 and RXFIFO_1) receive data buffers in the receive data buffer (RXFIFO) of each wireless radio receiver to store upcoming data packets, whenever the Cortex-M0 processor reads the When there is data in one RXFIFO, the other RXFIFO will continue to receive and store the upcoming data packets, which can effectively reduce the data packet loss rate. Each time the wireless data detection module receives a data message, it will automatically add the received signal strength indicator and the link quality indicator value to the back of the data message. The Cortex-M0 processor reads the data in the receive data buffer (RXFIFO) by continuously polling and reading the wireless RF transceiver. According to the length value of the message, after the main controller reads a complete data message, it will encapsulate the message validity header (such as: 0x66, 0xAB) in front of the message, so as to facilitate the host computer to validate the data. Identify and judge the nature of the protocol, and then upload it to the host computer through the serial port for decoding and analysis of the protocol. The data format transmitted by the controller to the host computer is as follows:

 

Note: 0x means hexadecimal; byte means byte, which consists of 8 bits.

Among them, the start bit—represents the frame header of the captured data packet, which occupies 2 bytes, and the value is 0x66, 0xAB.

Channel number——Indicates the channel number of the captured data, occupying 1 byte, and the value range: 0x0B-0x1A (that is, 11-26 in decimal).

PPDU - is the physical layer protocol data unit. Among them, the frame length is represented by the lower 7 bits of a byte, and its value represents the length of the physical frame load, so the length of the physical frame load will not exceed 127 bytes; The length determines its size.

LQI - is the Link Quality Indicator, which characterizes the received packet strength and quality. LQI occupies 1 byte, and its value range: 0x00-0xFF.

RSSI——is the received signal strength indicator, which is used to determine the link quality and whether to increase the broadcast transmission strength. RSSI occupies 1 byte.

As shown in Fig. 6, it is a structural diagram of the upper computer decoding analysis of the present invention. The upper computer decoding analysis of the present invention consists of three functional modules: data processing, system setting and man-machine interface. The three functional modules are described in detail below:

The data processing part includes a data receiving module, a data decoding and analyzing module, a data storage module, and a data display module.

The data receiving module receives the data message uploaded by the wireless data acquisition module through the serial port, and transmits it to the data analysis module; the data analysis module decodes and analyzes the detected data packets, including channel number, data length, protocol type, and link quality indicator value , the strength value of the signal packet, the receiving time stamp, and the statistics of the number of detected data packets, after analyzing according to the protocol type, the sending data display module displays it in table form, providing intuitive data analysis results. The system setup part includes a channel configuration module and a data type diagnosis module. The channel configuration module issues commands through the serial port to modify the channel for receiving data packets. in,

The format of the command is as follows:

The control command sequence is sent down in hexadecimal form. For example, if it is changed to channel 15 and channel 17, the control command sent down is: 0xCA 0x04 0x0F 0x11 (0x means hexadecimal). The data diagnosis type module provides a filter for the captured data message, judges whether it is a data message based on the IEEE802.15.4 protocol, and triggers afterwards, so that the analyzer can selectively capture data. The data processing part performs real-time or post-event monitoring and analysis on the data, and the analysis and processing process is discussed in detail below:

The wireless data acquisition module communicates with the upper computer through the serial port. In the data receiving module of the host computer, the serial port receiving function Rtn=ReadFile() (API function in C++, which reads data from the file from the position indicated by the file pointer) continues to read data messages from the serial port buffer, It is stored in the buffer and handed over to the data processing module for further parsing and processing. Serial port data receiving process is shown in Figure 5. In the Visual C++ environment, the UI thread (that is, the user interface thread) is created to receive data from the serial port, and the received original data is transmitted to the main thread through the thread message PostThreadMessage, and then parsed and displayed. The thread can be used for data processing and other operations without affecting the detection of data packets.

For example, the captured 6LowPAN data message is analyzed layer by layer according to the protocol type, and when analyzing the data message of each layer, the analysis results of the lower layer are used. During the protocol data parsing process, when the protocol type cannot be determined, the protocol type set by the user is used as the priority for parsing. The default priority parsing protocol type is 6LowPAN and ZigBee, that is, the 6LowPAN protocol is preferentially used to parse the data frame, and the beacon frame and MAC command frame are preferentially parsed using the ZigBee protocol, which ensures the compatibility with ZigBee.

First, the decoding analysis module distinguishes various protocols according to the flag bits of the data packet header. Then the frame type is determined by the frame type subfield (3 bits) in the frame control field of the MAC layer message header.

The frame type subfield values are as follows

Because both the ISA100.11a and 6LowPAN protocols only have data frame types, while the ZigBee and WIA-PA protocols include data frames, MAC command frames, and beacon frames. Therefore, if the type of the received data packet is a MAC command frame and a beacon frame, the data packet may be a ZigBee or WIA-PA data packet. At this time, the set priority protocol type is used to analyze layer by layer and byte by byte. If the preferred protocol type is ZigBee, it will be analyzed layer by layer and byte by ZigBee; if it is WIA-PA, it will be analyzed layer by layer and byte by WIA-PA. If the type of the data packet is a data frame, it will be analyzed layer by layer and byte by byte according to the priority type, so that the extended analysis of different protocols WIA-PA and ISA100.11a can be performed.

Taking 6LowPAN as an example, the flowchart of data packet parsing is shown in Figure 6. The detailed process steps of parsing are as follows:

(1) Open the serial port to receive the buffered data, and take the first and second bytes of the received data, and compare them with the two bytes 0x66 and 0xAB of the start bit encapsulated in the header respectively. If not equal, the received data is discarded. Otherwise continue parsing the data.

(2) Take out the third byte to get the channel number, and judge whether the value of the channel number is between the channel numbers 0x0B~0x1A of the captured data. If the value exceeds the range, the data will be discarded, otherwise continue to parse the data.

(3) Take out the fourth byte, get the length of the data and express it with Len, that is, the number of bytes in the load part of the physical layer, that is, the PDU (protocol data unit) of the MAC layer (ie, the media access control layer). If the data packet length is 5 or 9-127, continue parsing the data packet referring to IEEE Std 802.15.4-2006. Otherwise, the data is discarded.

(4) Starting from the fifth byte, take out the data length Len bytes obtained in (3). The obtained Len byte is the protocol data unit of the media access control layer. The bottom layer parses the data field by field according to the frame format of IEEE Std 802.15.4-2006.

(a) Take out the first and second bytes of the protocol data unit to obtain the frame control field information of the media access control layer. The frame control field of IEEE Std 802.15.4-2006 is 16 bits long, including the definition of frame type, address subfield and other control flags. Wherein, the bit length of the frame type subfield is 3 bits. Therefore, take out the lower 3 bits of the first byte to get the data type. If the value of the lower 3 bits is 001 (indicating a data frame), continue to parse the data. Otherwise, the data is discarded.

(b) After continuing to take out the information of the frame control field, take out the frame sequence number, address information, and the frame data unit of the media access control layer (taken to the Len-1th byte).

(c) In taking out the frame data unit of the media access control layer, first take out the lower 2 bits of the first byte, and then judge its type according to the frame type field in the frame control field of the network layer frame format of 6LowPAN. If the frame type is not a data frame, the frame data unit of the MAC layer is no longer parsed, and it is directly used as the load of the MAC layer, and the upper layer is no longer parsed. If it is a data frame, the address information and the frame data unit of the network layer are taken out according to the network layer frame format of 6LowPAN. In the frame data unit of the network layer, first take out the lower 2 bits of the first byte to get the frame type as data frame or command frame or confirmation frame; then take out the address information, application layer reader, extension header and application layer frame data unit.

(d) Take the Lenth byte and parse the end of the MAC frame.

(e) Take out the last two bytes and analyze them to get LQI and RSSI respectively.

(f) Display the analyzed data and store it in the database at the same time, so as to facilitate subsequent query and analysis.

Claims (2)

1. A two-channel data detection and protocol analyzer based on 6LowPAN, comprising, a wireless data acquisition module and an upper computer decoding analysis part, it is characterized in that the wireless data acquisition module includes a main controller, a wireless RF transceiver 1, a wireless RF Transceiver 2, USB interface module, host computer decoding and analysis part includes system setting module, data processing module and man-machine interface, main controller performs bus operation through two serial peripheral device interfaces of synchronous serial port controller, respectively controls Wireless RF transceiver 1 and wireless RF transceiver 2, through two wireless RF transceivers, poll and scan the 16 original channel sequence lists. When scanning each channel, when the maximum time value of monitoring each channel data is still If there is no data message, it will automatically switch to the next adjacent channel number according to the original channel sequence table. For the 6LowPAN data message, the address information and the frame data unit of the network layer are taken out according to the frame format of the network layer of 6LowPAN. In the frame data unit, first take out the lower 2 bits of the first byte to obtain the frame type as data frame, then take out the address information, application layer reader, extension header and application layer frame data unit; put the effective data message Stored in the data cache of their respective wireless RF transceivers, the main controller encapsulates the header and channel number of the data message and uploads it to the host computer; the data analysis module of the host computer decodes and analyzes the detected data message according to the priority type The text is analyzed layer by layer and byte by byte, and then sent to the data display module after analysis according to the protocol type. The system setting part sends commands through the serial port to modify the channel for receiving data messages. 2. A two-channel data detection and protocol analysis method based on 6LowPAN is characterized in that the main controller of the wireless data acquisition part carries out bus operation through two serial peripheral device interfaces of the synchronous serial port controller, and controls the wireless respectively RF transceiver 1 and wireless RF transceiver 2, through the two wireless RF transceivers, poll and scan the 16 original channel sequence lists. When scanning each channel, there is still no data within the maximum time value of monitoring each channel data. The data message is automatically switched to the next adjacent channel number according to the original channel sequence table. For the 6LowPAN data message, the address information, the frame data unit of the network layer, and the frame data of the network layer are taken out according to the frame format of the network layer of 6LowPAN. In the data unit, first take out the lower 2 bits of the first byte to obtain the frame type as data frame, then take out the address information, application layer reader, extension header and application layer frame data unit; store the effective data message In the data cache of their respective wireless RF transceivers, the main controller encapsulates the header and channel number of the data message and uploads it to the host computer; the decoding and analysis part of the host computer decodes and analyzes the detected data message , after analyzing according to its protocol type, send the analyzed data message to the data display module, and the system setting part sends a command through the serial port to modify the channel for receiving the data message.