A method for transmitting key data based on a unidirectional transmission device

Abstract

The application relates to the technical field of data transmission, in particular to a key data transmission method based on one-way transmission equipment, which comprises the following steps: S1, initialization configuration; S2, module starting; S3, data receiving and coding; S4, event sending; S5, event receiving and queuing; S6, data decoding and recovery; and S7, data forwarding. The application adopts an innovative event driving and coding combination mechanism, provides higher data transmission reliability, converts data transmission into a state combination based on underlying system events, fully utilizes an event reliability guarantee mechanism of an operating system kernel level, and greatly ensures complete data transmission. The scheme avoids system burdens caused by a traditional data processing mode and can provide reliable data integrity guarantee for an industrial control system in a one-way non-feedback environment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of data transmission, in particular to a key data transmission method based on one-way transmission equipment. BACKGROUND

[0002] In industrial control systems, the transmission of key data (including control instructions, safety states, sensor readings, etc.) has extremely strict requirements for reliability. In special industrial environments such as power dispatching, nuclear power plant control, and railway signal systems, due to safety protection considerations, one-way transmission mechanisms must be used to prevent information backflow. At the same time, due to physical isolation or safety policy requirements, the transmission channel usually does not allow any form of feedback information, which makes the traditional reliability mechanism based on acknowledgement and retransmission inapplicable.

[0003] In this strict one-way and non-feedback transmission environment, ensuring the reliable transmission of key data faces major technical challenges. The existing technical solutions have obvious deficiencies in data reliability:

[0004] 1. The simple retransmission mechanism based on UDP improves reliability by retransmitting data packets multiple times, but this method may still result in continuous packet loss and permanent data loss when the network condition deteriorates or the receiving end processing capacity is insufficient.

[0005] 2. The scheme based on forward error correction (FEC) improves reliability by adding redundant data at the sending end, but its error correction capability is limited and cannot guarantee data recovery in the case of continuous packet loss, and the encoding and decoding process will introduce additional computational burden.

[0006] 3. The multi-channel redundant transmission scheme improves reliability by sending the same data through multiple independent channels, but the data synchronization and complex deduplication mechanism between channels will introduce new unreliable factors, and data loss may occur simultaneously when the system load is high. SUMMARY

[0007] To overcome the deficiencies of the prior art, the present application provides a key data transmission method based on one-way transmission equipment, which converts data transmission into a state combination based on underlying system events, fully utilizes the event reliability guarantee mechanism at the operating system kernel level, greatly ensures the complete transmission of data, avoids the system burden brought by traditional data processing methods, and can provide reliable data integrity protection for industrial control systems in a one-way and non-feedback environment.

[0008] The present application is realized by the following technical solutions:

[0009] The application provides a key data transmission method based on a one-way transmission device, which comprises an upper layer device and a lower layer device, wherein the upper layer device comprises a configuration management module, a communication agent module, a data coding module and an event sending module; the lower layer device comprises a configuration management module, an event receiving module, a data decoding module and a data transmission module.

[0010] The method comprises the following steps:

[0011] S1, initialization configuration: the upper layer device and the lower layer device are respectively initialized according to the configuration management module;

[0012] S2, module starting: the upper layer device starts the communication agent module, the data coding module and the event sending module; the lower layer device starts the event receiving module, the data decoding module and the data transmission module;

[0013] S3, data receiving and coding: the control end connects the communication agent module of the upper layer device and sends signal data; the communication agent module receives the signal data and sends the signal data to the data coding module; the data coding module codes the signal data into a coded data block in a predetermined format;

[0014] S4, event sending: the event sending module maps each bit of the coded data block into an independent system event, and sends a data packet representing the system event to the lower layer device through a plurality of independent one-way transmission channels; the system event is distinguished by the load characteristics of the data packet;

[0015] S5, event receiving and queuing: the event receiving module of the lower layer device listens to the plurality of one-way transmission channels, receives the data packet from the upper layer device, and according to the characteristics of each data packet, stores the corresponding binary event state value into the event queue corresponding to the channel;

[0016] S6, data decoding and recovery: the data decoding module periodically reads the event state value from all the event queues, if a complete set of event state values is successfully read within a preset timeout time, the read state values are combined and restored into a coded data block according to the index number of each event queue; if the timeout time is exceeded, the data of this round is discarded;

[0017] S7, data forwarding: the data decoding module decodes the restored coded data block to obtain the original signal data, and sends the original signal data to the corresponding target point by the data transmission module.

[0018] Further, in step S3, the coded data block in the predetermined format is a 32-bit data structure, which comprises, from low to high, a 6-bit cyclic sequence number field, a 2-bit data type identification field, an 8-bit target point index field and a 16-bit actual data load field.

[0019] Further, the data type identification field is used to identify the type of signal data, and its value includes: 00 represents switch value, 01 represents integer value, 10 represents custom data type, and 11 is reserved value.

[0020] Further, in step S4, the specific process of mapping each bit to a system event includes:

[0021] A corresponding UDP sending client is created for each bit index of the encoded data block; each bit of the encoded data block is traversed;

[0022] If the bit value is 0, it indicates that the corresponding UDP sending client sends a first type of data packet;

[0023] If the bit value is 1, it indicates that the corresponding UDP sending client sends a second type of data packet;

[0024] The first type of data packet and the second type of data packet have different load characteristics.

[0025] The load of the first type of data packet is empty, and the load of the second type of data packet contains at least one byte of data.

[0026] Further, the specific process of step S5 includes:

[0027] A UDP server and an event queue corresponding thereto are created for each unidirectional transmission channel;

[0028] Read events of the UDP servers are listened to;

[0029] When a data packet is received, the event type is determined according to the load characteristics thereof:

[0030] If it meets the first type of characteristics, a first state value is stored in the corresponding event queue;

[0031] If it meets the second type of characteristics, a second state value is stored in the corresponding event queue.

[0032] Further, the data encoding module includes a first buffer queue for storing signal data from the communication agent module, and the signal data is sequentially taken from the first buffer queue for encoding; the event sending module includes a second buffer queue for buffering the encoded data block from the data encoding module, and the encoded data block is sequentially taken from the second buffer queue for event sending; the data decoding module includes a third buffer queue for buffering the restored encoded data block, and the encoded data block is sequentially taken from the third buffer queue for decoding.

[0033] Further, the configuration information stored by the configuration management module at least includes connection information for defining a communication port, index information for matching a target point, and a timeout parameter for controlling a decoding process.

[0034] Preferably, the connection information includes a proxy end address port and a transmission channel address port set; the index information includes a target point address port set, a target point switch value index, a target point numerical data index, and a target point custom data index; and the timeout parameter is a decoding timeout time.

[0035] As a preferred, by increasing N groups of parallel data encoding modules, event sending modules, event receiving modules and data decoding modules, and correspondingly increasing N groups of one-way transmission channel sets, wherein each group of channel sets contains a plurality of independent one-way transmission channels; the system can process N encoded data blocks in parallel, realizing linear improvement of data transmission throughput.

[0036] The beneficial effects of the present application are:

[0037] I. Utilize the non-losable characteristics of the operating system kernel to process I / O events, encode data into underlying event states for transmission, and ensure reliable delivery of critical instructions and state information from the physical layer and system bottom, overcoming the reliability bottleneck of traditional solutions (such as UDP retransmission, forward error correction FEC, and multi-channel redundancy) in a one-way non-feedback environment, improving the reliability of data transmission from "probability" to "determinism", and greatly reducing the risk of permanent data loss.

[0038] II. The event data packet is extremely small (the load is only 0 or 1 byte), which greatly saves network bandwidth, especially suitable for narrowband industrial environment, and the receiving end processes events in batches based on efficient I / O mechanisms such as epoll / io_uring, and the decoding logic is simple (state combination), avoiding the computational burden caused by complex FEC encoding and decoding, and significantly improving the data processing performance. The architecture supports linear improvement of system throughput by increasing parallel encoding and decoding module groups, and there is no data synchronization dependency between groups, which has excellent scalability and avoids the disadvantages of complex synchronization of traditional multi-channel solutions.

[0039] Thirdly, the strict one-way transmission mechanism meets the safety isolation requirement of the industrial control system, prevents information backflow, and the "all-or-nothing" decoding mechanism (time-out discarding incomplete data) ensures the determinacy of the receiving end behavior, thereby significantly improving the functional safety level of the system; avoids complex confirmation, retransmission, synchronization and deduplication mechanisms, reduces the system complexity, thereby reducing potential failure points, improving the stability and robustness of the overall system, and ensuring the key data transmission in safety demanding scenarios such as power dispatching and nuclear power plant control, significantly improving the safety and operation stability of the industrial control system, while avoiding the high cost and complexity brought by the traditional redundancy scheme, providing a reliable and practical communication solution for industrial critical infrastructure.

[0040] In summary, the application converts the reliability problem of network data transmission into the reliability problem of operating system kernel events through a clever event-driven mechanism, thereby realizing a leap in reliability, performance and safety under the extreme constraint condition of one-way non-feedback, and providing vital communication protection for industrial critical infrastructure. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is the system architecture module diagram of the one-way transmission device in the embodiment of the application.

[0042] Figure 2 is the overall flowchart of the key data transmission in the embodiment of the application.

[0043] Figure 3 is the working flowchart of the data encoding module in the embodiment of the application.

[0044] Figure 4 is the working flowchart of the event sending module in the embodiment of the application.

[0045] Figure 5 is the working flowchart of the event receiving module in the embodiment of the application.

[0046] Figure 6 is the working flowchart of the data decoding module in the embodiment of the application.

[0047] Figure 7 is the working flowchart of the data transmission module of the lower layer device in the embodiment of the application. DETAILED DESCRIPTION

[0048] To clearly illustrate the technical features of the scheme, the following describes the scheme through specific embodiments.

[0049] A key data transmission method based on a one-way transmission device, the one-way transmission device comprising an upper layer device and a lower layer device, the method comprising the following steps:

[0050] S1, initialization configuration: the upper-layer device and the lower-layer device are respectively initialized according to a configuration management module; the configuration information stored by the configuration management module at least includes connection information for defining a communication port, index information for matching a target point, and a timeout parameter for controlling a decoding process. The connection information includes a proxy address port and a transmission channel address port set; the index information includes a target point address port set, a target point switch value index, a target point numerical value type data index, and a target point self-defined data index; and the timeout parameter is a decoding timeout time.

[0051] The proxy address port is used for starting a communication agent of the upper-layer device.

[0052] The transmission channel address port set is used for creating a sending client and a listening server by an event transceiver module.

[0053] The target point address port set is used for condition matching of data selection.

[0054] The target point switch value index is used for matching switch value specific information of the target point by the device.

[0055] The target point numerical value type data index is used for matching numerical value type data information of the target point by the device.

[0056] The target point self-defined data index is used for matching specific information of the target point by the device.

[0057] The switch value index, the numerical value type data index, and the self-defined data index are subsets of the target address port.

[0058] S2, module startup: the upper-layer device starts a communication agent module, a data encoding module, and an event sending module; and the lower-layer device starts an event receiving module, a data decoding module, and a data transmission module.

[0059] S3, data receiving and encoding: a control end connects the communication agent module of the upper-layer device and sends signal data; the communication agent module receives the signal data and sends the signal data to the data encoding module; and the data encoding module encodes the signal data into an encoding data block in a predetermined format.

[0060] The encoding data block in the predetermined format is a 32-bit data structure, which includes, from low to high, a 6-bit cyclic sequence number field, a 2-bit data type identification field, an 8-bit target point index field, and a 16-bit actual data payload field.

[0061] The data type identification field is used for identifying the type of the signal data, and the value thereof includes: 00 represents a switch value, 01 represents an integer value, 10 represents a self-defined data type, and 11 is a reserved value.

[0062] The sequence number field is a cyclic sequence number of 0-63, the target point index field is used to match the point address in the configuration file; in the actual data payload field, when the data type is a switch value, 16 switch values can be represented at most, and when the data type is an integer value, -32768-32767 is represented.

[0063] S4, event sending: the event sending module maps each bit of the encoded data block to an independent system event, and sends the data packet representing the system event to the lower layer device through multiple independent unidirectional transmission channels.

[0064] The specific process of mapping each bit to a system event includes:

[0065] A corresponding UDP sending client is created for each bit index number of the encoded data block; each bit of the encoded data block is traversed;

[0066] If the bit value is 0, the corresponding UDP sending client sends a first type of data packet;

[0067] If the bit value is 1, the corresponding UDP sending client sends a second type of data packet;

[0068] The first type of data packet and the second type of data packet have different load characteristics.

[0069] The load of the first type of data packet is empty, and the load of the second type of data packet contains at least one byte of data.

[0070] S5, event receiving and queuing: the event receiving module of the lower layer device listens to multiple unidirectional transmission channels, receives data packets from the upper layer device, and according to the characteristics of each data packet, stores the corresponding binary event state value into the event queue corresponding to the channel.

[0071] A UDP server and an event queue corresponding thereto are created for each unidirectional transmission channel;

[0072] Listen to the read event of each UDP server;

[0073] When a data packet is received, the event type is determined according to the load characteristics thereof:

[0074] If it meets the first type of characteristics, the first state value is stored into the corresponding event queue;

[0075] If it meets the second type of characteristics, the second state value is stored into the corresponding event queue.

[0076] S6, data decoding and recovery: the data decoding module periodically reads event state values from all event queues, if a complete set of event state values is successfully read within the preset timeout time, the read state values are combined and restored to the encoded data block according to the index number of each event queue; if the timeout, discard the data of this round.

[0077] S7, data forwarding: the data decoding module decodes the restored encoded data block to obtain the original signal data, and sends it to the corresponding target point by the data transmission module.

[0078] The data encoding module includes a first buffer queue for storing signal data from the communication agent module and sequentially taking out signal data from the first buffer queue for encoding; the event sending module includes a second buffer queue for buffering encoded data blocks from the data encoding module and sequentially taking out encoded data blocks from the second buffer queue for event sending; the data decoding module includes a third buffer queue for buffering restored encoded data blocks and sequentially taking out encoded data blocks from the third buffer queue for decoding.

[0079] By increasing N groups of parallel data encoding modules, event sending modules, event receiving modules and data decoding modules, and correspondingly increasing N groups of one-way transmission channel sets, each group of channel sets includes a plurality of independent one-way transmission channels; the system can process N encoded data blocks in parallel, realizing linear improvement of data transmission throughput.

[0080] The embodiment provides a complete system implementation for reliably transmitting industrial control system switch signals on a one-way UDP channel.

[0081] Referring to Figure 1 , the one-way transmission device is divided into an upper layer device and a lower layer device.

[0082] The upper layer device includes: a configuration management module, a communication agent module, a data encoding module and an event sending module.

[0083] The lower layer device includes: a configuration management module, an event receiving module, a data decoding module and a data transmission module.

[0084] The configuration management module stores the following key information:

[0085] Agent address port: for example, 192.168.1.10:5000, for the control end to connect.

[0086] Transmission channel address port set: including 32 UDP address port pairs, used to establish 32 independent one-way channels.

[0087] Target point address port set: e.g. [("PLC1", "192.168.3.10:2000"), ("PLC2", "192.168.3.11:2000")].

[0088] Target point switch index: e.g. {"PLC1": [0, 1, 2,..., 15], "PLC2": [16, 17,..., 31]}, corresponding point to data.

[0089] Decoding timeout time (Time): e.g. 50ms.

[0090] When the system starts, the upper and lower layer devices read the configuration file respectively, and complete the initialization of each module. The upper layer device starts the communication agent module to listen to the specified port, and initializes 32 UDP clients (Clis). The lower layer device initializes 32 UDP servers (Servs), each server corresponds to an event queue (Qs), and creates a Socket connection to the target point (such as PLC1, PLC2).

[0091] Data transmission process, see Figure 2 :

[0092] The control end sends an instruction data containing 16 switch states to the communication agent module. The communication agent module receives the data and puts it into the buffer queue of the data encoding module.

[0093] See Figure 3 , the data encoding module performs the following steps:

[0094] S301: Initialize a 32-bit data structure A, all bits are 0.

[0095] S302: Take out the instruction data from the buffer queue. Suppose the instruction is to send switch state [1, 0, 1, 0,..., 1] (total 16 bits) to point PLC1.

[0096] S303: Sequence number S is incremented by 1 (cycle 0-63). Data type T is set to 00 (switch). Target point P is converted to 8-bit binary according to the index of PLC1 configuration, for example 00000001.

[0097] S304: Fill the 16 switch states in order into the 16-bit actual data field D, and finally generate a 32-bit data structure A.

[0098] S305: Send A to the buffer queue of the event sending module.

[0099] See Figure 4 , the event sending module performs the following steps:

[0100] S401: The module has initialized 32 UDP clients Clis[0] to Clis

[31] .

[0101] S402: Take out data structure A from the buffer queue and parse it bit by bit; suppose the 0th bit of A is 1, the 1st bit is 0, and the 31st bit is 1.

[0102] S403: Notify each client to send an event in parallel: notify Clis[0] to send event E1 (because A[0] = 1), notify Clis[1] to send event E0 (because A[1] = 0), and so on, notify Clis

[31] to send event E1 (because A

[31] = 1).

[0103] S404: After each client receives the notification, it performs sending: for the E0 event, send a UDP packet with an empty load; for the E1 event, send a UDP packet with a load of 1 byte (content is 0); these 32 tiny UDP packets are sent to the lower layer device through 32 independent channels.

[0104] Referring to Figure 5 , the event receiving module of the lower layer device performs the following steps:

[0105] S501: The module has initialized 32 UDP servers Servs[0] to Servs

[31] and their corresponding queues Qs[0] to Qs

[31] .

[0106] S502: The kernel notifies that a packet has arrived. Suppose Servs[0] receives a packet.

[0107] S503: Read the packet and find that its load length is greater than 0, judging it as an E1 event, and store the binary value 1 at the tail of the queue Qs[0]. Similarly, Servs[1] receives an empty packet and stores 0 in Qs[1].

[0108] Referring to Figure 6 , the data decoding module performs the following steps:

[0109] S601: Initialize data structure A, all bits are 0.

[0110] S602: Synchronously attempt to read a value from the head of each of the 32 event queues Qs[0] to Qs

[31] .

[0111] S603: Determine whether 32 values have been successfully read within a 50ms timeout.

[0112] If yes (success): go to S604. Set the read value to the corresponding bit of A according to the queue index: A[0] = Qs[0] read value (1), A[1] = Qs[1] read value (0),..., A

[31] = Qs

[31] read value (1); at this point, the data block is completely restored to A.

[0113] If no (timeout): go to S605; discard the incomplete data of this round, and wait for the next round. This is the key to ensure data integrity.

[0114] S606: send the successfully restored complete data structure A to the buffer queue of the data transmission module.

[0115] Referring to Figure 7 , the data transmission module performs the following steps:

[0116] S701: take out the data structure A from the queue.

[0117] S702: parse the target point field P (00000001) of A, which corresponds to PLC1. Parse the actual data field D to obtain 16 switch states [1, 0, 1, 0,..., 1].

[0118] S703: according to the protocol of PLC1 in the configuration, encapsulate the switch states into a PLC recognizable data packet PKT.

[0119] S704: send PKT to PLC1 through the established Socket connection to 192.168.3.10:2000.

[0120] At this point, a complete one-way reliable transmission process is completed. The system continues to run and processes subsequent data.

[0121] Of course, the above description is not limited to the above examples, and the technical features not described in the present application can be implemented by or using existing technology, which will not be described here; the above embodiments and drawings are only used to illustrate the technical solutions of the present application and are not a limitation of the present application. The above embodiments and drawings are only used to illustrate the technical solutions of the present application and are not a limitation of the present application. The person skilled in the art should understand that the changes, modifications, additions or substitutions made by the person skilled in the art within the essential scope of the present application do not deviate from the purpose of the present application, and should also belong to the protection scope of the claims of the present application.

Claims

1. A key data transmission method based on a unidirectional transmission device, characterized in that: Unidirectional transmission devices include upper-layer and lower-layer devices, and the method is as follows: S1. Upper-layer and lower-layer devices are initialized according to the configuration management module; S2. The upper-layer device starts the communication proxy module, data encoding module, and event sending module; the lower-layer device starts the event receiving module, data decoding module, and data transmission module. S3. The control terminal connects to the communication proxy module and sends signal data; the communication proxy module receives the signal data and sends it to the data encoding module; the data encoding module encodes the signal data into encoded data blocks of a predetermined format. S4. The event sending module maps each bit of the encoded data block to an independent system event, and sends the data packet representing the system event to the lower-level device through a one-way transmission channel. The system events are distinguished by the characteristics of the data packet payload. S5. The event receiving module listens to the one-way transmission channel, receives data packets from the upper-layer device, and stores the corresponding binary event status value into the event queue corresponding to the channel according to the characteristics of each data packet. S6. The data decoding module reads event status values ​​from all event queues. If a complete set of event status values ​​is read within the preset timeout period, the read status values ​​are combined and restored into encoded data blocks according to the index number of each event queue. If the timeout occurs, discard the data from this round. S7. The data decoding module decodes the restored encoded data block to obtain the original signal data, which is then sent to the corresponding target location by the data transmission module.

2. The key data transmission method based on a unidirectional transmission device according to claim 1, characterized in that: In step S3, the pre-formatted encoded data block is a 32-bit data structure, which includes, from low to high bits, a 6-bit cyclic sequence number field, a 2-bit data type identifier field, an 8-bit target point index field, and a 16-bit actual data payload field.

3. The key data transmission method based on a unidirectional transmission device according to claim 2, characterized in that: The data type identifier field is used to identify the type of signal data, and its values ​​include: 00 represents a switch value, 01 represents an integer value, 10 represents a user-defined data type, and 11 is a reserved value.

4. The key data transmission method based on a unidirectional transmission device according to claim 1, characterized in that: In step S4, the specific process of mapping each bit to a system event includes: Create a corresponding UDP sending client for each index number of the encoded data block; iterate through each bit of the encoded data block; If the value of this bit is 0, it indicates that the corresponding UDP sending client should send a Type 1 data packet; If the value of this bit is 1, it indicates that the corresponding UDP sending client should send a Type 2 data packet; Among them, the first type of data packet and the second type of data packet have different load characteristics.

5. The key data transmission method based on a unidirectional transmission device according to claim 4, characterized in that: The payload of the first type of data packet is empty, while the payload of the second type of data packet contains at least one byte of data.

6. The key data transmission method based on a unidirectional transmission device according to claim 1, characterized in that: The specific process of step S5 includes: Create a UDP server and a corresponding event queue for each one-way transmission channel; Listen for read events from each UDP server; When a data packet is received, the event type is determined based on its payload characteristics: If it meets the first type of characteristics, then store the first state value in the corresponding event queue; If the second type of characteristic is met, the second state value is stored in the corresponding event queue.

7. The key data transmission method based on a unidirectional transmission device according to claim 1, characterized in that: The data encoding module includes a first buffer queue for storing signal data from the communication proxy module, and sequentially retrieves signal data from the first buffer queue for encoding; the event sending module includes a second buffer queue for caching encoded data blocks from the data encoding module, and sequentially retrieves encoded data blocks from the second buffer queue for event-based sending; the data decoding module includes a third buffer queue for caching restored encoded data blocks, and sequentially retrieves encoded data blocks from the third buffer queue for decoding.

8. The key data transmission method based on a unidirectional transmission device according to claim 1, characterized in that: The configuration management module stores configuration information including at least connection information for defining communication ports, index information for matching target locations, and timeout parameters for controlling the decoding process.

9. The key data transmission method based on a unidirectional transmission device according to claim 7, characterized in that: The connection information includes the agent's address and port and the transmission channel's address and port set; the index information includes the target point's address and port set, the target point's switch quantity index, the target point's numerical data index, and the target point's custom data index; the timeout parameter is the decoding timeout period.

10. The key data transmission method based on a unidirectional transmission device according to claim 1, characterized in that: By adding N sets of parallel data encoding modules, event sending modules, event receiving modules, and data decoding modules, and correspondingly adding N sets of unidirectional transmission channels, where each set of channels contains multiple independent unidirectional transmission channels, the system can process N encoded data blocks in parallel, achieving a linear increase in data transmission throughput.

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