CN111565140A

CN111565140A - Distributed aeronautical communication middleware capable of simultaneously supporting CAN bus and Ethernet

Info

Publication number: CN111565140A
Application number: CN202010279920.7A
Authority: CN
Inventors: 吴夏风; 赵羚钧
Original assignee: CETC Avionics Co Ltd
Current assignee: CETC Avionics Co Ltd
Priority date: 2020-04-10
Filing date: 2020-04-10
Publication date: 2020-08-21
Anticipated expiration: 2040-04-10
Also published as: CN111565140B

Abstract

The invention discloses a distributed aeronautical communication middleware which simultaneously supports a CAN bus and an Ethernet, wherein the aeronautical communication middleware works under a linux system and realizes the control of a physical bus by depending on an interface provided by an operating system; the aviation communication middleware comprises a bus adaptation module, a routing management module and an interface API; the bus adaptation module is used for shielding the difference of bus operation processes, abstracting various operations of the Ethernet and the CAN bus into the same set of operation process, and providing a data structure and an operation function for accessing the bus to the routing management module; the route management module is responsible for analyzing the received message in the message receiving process, determining whether the message needs to be forwarded according to the message information, and searching a correct route in the message sending process to send the message out; the interface API is responsible for providing a uniform interface for external programs. The invention can shield different bus differences in the avionic system and realize data receiving and transmitting among different bus devices.

Description

Distributed aeronautical communication middleware capable of simultaneously supporting CAN bus and Ethernet

Technical Field

The invention relates to the technical field of distributed communication middleware, in particular to distributed aviation communication middleware which simultaneously supports a CAN bus and an Ethernet and a message receiving and sending method thereof.

Background

With the development of electronic technology, on-board systems are becoming more complex in the field of civil Avionics (Avionics). Civil avionics not only relates to general equipment meeting basic functions such as communication, navigation, identification, flight management, atmospheric data, radar, electronic display control and the like, but also has systems for performing optimized experiences such as audio control, passenger service, cabin control, wireless internet access, multimedia service and the like.

Due to the multitude of devices, the physical bus between the devices is complex. When a scene of communication between devices is designed, a large amount of manpower is consumed for business software to perform adaptation development aiming at a bus, and communication codes between different devices have a plurality of similar redundant business processes, so that waste is caused to a certain extent. Therefore, it is necessary to provide an aviation communication middleware to shield different bus differences and standardize the communication interface between devices.

The Ethernet is the backbone of the modern Internet, has the characteristics of high speed, high performance, good universality and the like, and is widely applied to avionic systems; the CAN bus is a communication bus widely applied in the field of automatic control in the electronic industry, and has the characteristics of high reliability, simplicity, easy realization and the like. The aviation system has a scene that data is transmitted through a CAN bus, then transmitted through an Ethernet and finally transmitted to a target through the CAN bus, service software needs to realize a special transmitting mechanism, the transmitting is irrelevant to a service model, the complexity of the service system and the coupling degree of software and hardware are increased, the service system needs to be stripped from service logic urgently, and aviation communication middleware is used for shielding specific transmitting logic.

Because the safety of the avionics system is considered, all subsystems and data service flows are mutually backed up, and the working capacity of the avionics system is not influenced after a certain system fault is ensured, the traditional centralized middleware system cannot be applied to the avionics field.

Disclosure of Invention

In order to overcome the limitation that the traditional centralized middleware system cannot be applied to the field of avionics, the invention provides a distributed avionics middleware which simultaneously supports a CAN bus and an Ethernet. The distributed middleware structure is adopted, and the distributed middleware structure can be well applied to the field of avionics.

The invention is realized by the following technical scheme:

the distributed aeronautical communication middleware simultaneously supports a CAN bus and an Ethernet, works under a linux system, and realizes the control of a physical bus by depending on an interface provided by an operating system; the aviation communication middleware comprises a bus adaptation module, a routing management module and an interface API;

the bus adaptation module is used for shielding the difference of bus operation processes, abstracting various operations of the Ethernet and the CAN bus into the same set of operation process, and providing a data structure and an operation function for accessing the bus to the routing management module;

the routing management module is responsible for analyzing the received message in the message receiving process and determining whether the message needs to be forwarded or not according to the message information; searching a correct route in the message sending process to send out the message;

the interface API is responsible for providing a uniform interface for external programs.

The communication middleware structure is deployed on each device in the avionics system, the avionics middleware adopts a distributed architecture, a central node does not exist, and business programs on the avionics devices only need to link the middleware to call an interface of the avionics communication middleware so as to realize the receiving and sending of data between devices connected by different physical buses.

Preferably, the Ethernet operation and the CAN bus operation are both based on socket interfaces.

Preferably, the aeronautical communication middleware provided by the invention adopts a distributed architecture.

Preferably, the aeronautical communication middleware port of the present invention defines: within an ethernet network, each combination of IP plus ports is treated as a middleware port; on the CAN bus, each CAN bus controller plus CAN ID combination is treated as a middleware port.

Preferably, the port of the aeronautical communication middleware of the present invention is a linked list structure, which includes: next _ node, middleware port address addr, port type pt _ type, union type low _ Info, container pointer to current linked list, set of middleware port operation functions cmu _ ops, and lock pt _ lock.

Preferably, the operation on the middleware port in the present invention is encapsulated as a function pointer structure, where each pointer points to a corresponding function implementation, and the method includes: the Init operation encapsulates the socket creation operation; active packages socket binding operation, Stop modification state, Release corresponding to Release, modification of socket binding address after Update modifies routing forwarding table, Send packet sending operation and recv packet receiving operation.

Preferably, the forwarding rule of the routing forwarding table on each device in the avionics system in the present invention includes: the global number of the current forwarding rule, the type of the forwarding data, the port address of the destination middleware, which local middleware port needs to send a message to reach the destination middleware port, the port address of the next hop middleware, and whether the current forwarding rule is normal or not.

Preferably, the interface API of the present invention includes: initializing a middleware function Mw _ init, sending a message interface function MW _ send, receiving a message interface function MW _ recv, modifying and setting a static forwarding table information function MW _ set _ opt, and acquiring the static forwarding table information function MW _ get _ opt.

On the other hand, the invention also provides a message receiving method of the aeronautical communication middleware, wherein after the bus adaptation module reads out the message from the bus, the corresponding message is transmitted to the route management module, and the route management module executes the following operations:

s1, analyzing the destination middleware port address, the source middleware port address and the data type in the message header;

s2, confirming whether the destination middleware port is on the current device, if yes, sending the data to the caller of the interface API;

s3, otherwise, searching the route forwarding table, if the forwarding rule is found in the route forwarding table, sending the message from the corresponding middleware port;

s4, if the routing rule can not be found in the routing forwarding table, discarding the corresponding message;

s5, if a forwarding rule can be found in the route forwarding table but the rule status is unavailable and no other forwarding rule can be found that can send the data to the destination middleware port, the corresponding message is discarded.

In addition, the invention also provides a message sending method of the aeronautical communication middleware, in the message sending process, the interface API transmits the input parameter to the route management module, and the route management module executes the following operations:

s1, finding the middleware port for sending information through the source middleware port address, if the current device does not use the corresponding middleware port, the sending fails;

s2, searching the forwarding specification of the destination middleware port in the route forwarding table, if not, the sending is failed;

s3, if finding the forwarding rule, sending the message from the corresponding middleware port;

s4, if a forwarding rule is found but the rule status is not available and no other rule capable of forwarding data to the destination middleware port is found, the forwarding fails.

The invention has the following advantages and beneficial effects:

the aviation communication middleware adopts a distributed architecture, CAN be compatible with the operation of Ethernet and CAN buses, and CAN shield different bus differences in an avionics system and realize data receiving and transmitting among different bus devices by only deploying the aviation communication middleware on each device in the avionics system.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

fig. 1 shows the architecture of the aeronautical communication middleware and its deployment in the avionics system equipment.

Detailed Description

Hereinafter, the term "comprising" or "may include" used in various embodiments of the present invention indicates the presence of the invented function, operation or element, and does not limit the addition of one or more functions, operations or elements. Furthermore, as used in various embodiments of the present invention, the terms "comprises," "comprising," "includes," "including," "has," "having" and their derivatives are intended to mean that the specified features, numbers, steps, operations, elements, components, or combinations of the foregoing, are only meant to indicate that a particular feature, number, step, operation, element, component, or combination of the foregoing, and should not be construed as first excluding the existence of, or adding to the possibility of, one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing.

In various embodiments of the invention, the expression "or" at least one of a or/and B "includes any or all combinations of the words listed simultaneously. For example, the expression "a or B" or "at least one of a or/and B" may include a, may include B, or may include both a and B.

Expressions (such as "first", "second", and the like) used in various embodiments of the present invention may modify various constituent elements in various embodiments, but may not limit the respective constituent elements. For example, the above description does not limit the order and/or importance of the elements described. The foregoing description is for the purpose of distinguishing one element from another. For example, the first user device and the second user device indicate different user devices, although both are user devices. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of various embodiments of the present invention.

It should be noted that: if it is described that one constituent element is "connected" to another constituent element, the first constituent element may be directly connected to the second constituent element, and a third constituent element may be "connected" between the first constituent element and the second constituent element. In contrast, when one constituent element is "directly connected" to another constituent element, it is understood that there is no third constituent element between the first constituent element and the second constituent element.

The terminology used in the various embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the various embodiments of the invention. As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments of the present invention belong. The terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning that is consistent with their contextual meaning in the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein in various embodiments of the present invention.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.

Example 1

The embodiment provides a distributed aeronautical communication middleware which supports a CAN bus and an Ethernet simultaneously.

The middleware of this embodiment works under the linux system, and realizes control over the physical bus by relying on an interface provided by an operating system. As shown in fig. 1, the middleware of the present embodiment mainly includes a bus adaptation module, a route management module, and an interface API.

The bus adaptation module shields the difference of bus operation processes, abstracts various operations of the Ethernet and the CAN buses into the same set of operation processes, and provides a data structure and an operation function for accessing the buses for the routing management module in the middleware.

The routing management module is responsible for analyzing the received message in the message receiving process and determining whether the message needs to be forwarded or transmitted to service layer software of equipment where the current aviation communication middleware is located according to the message information; and finding the correct route to send the message in the message sending process. The interface layer is responsible for providing a uniform interface for external programs.

Communication middleware needs to be deployed on each device in the avionics system. The aviation middleware adopts a distributed architecture, and a central node does not exist. A network card and a CAN bus controller may be simultaneously provided on a single device, and the aviation middleware on each device has a capability of forwarding messages, for example, device a in fig. 1 may communicate with device H, and device F and device G are required to forward in the middle.

Encapsulation of CAN bus and Ethernet operation flow and data structure

Middleware port definition: in ethernet, each combination of IP plus port is treated as a middleware port, and on CAN bus, each combination of CAN bus controller plus CAN id is treated as a middleware port.

Each middleware port has its own 4-byte port address. Avionics systems are static systems and do not change dynamically. In the design phase of the avionics system, each middleware port needs to be assigned a fixed port address in advance as a basis for addressing them, and the data structure for describing the middleware port is:

the structure is a linked list, and the next _ node points to the next element; addr is the middleware port address; pt _ type is a port type; the low _ Info is a union type, the Ethernet scene points to a structural body containing an IP and a port, and the CAUBUS scene points to a structural body containing a CAN controller device name and a CANID; container points to the container of the current linked list, cmu _ ops is the set of functions operating on the middleware port, pt _ lock is the lock, and resv is the reserved field.

The operation of the middleware port is packaged into a function pointer structure body, and each pointer in the function pointer structure body points to the corresponding function to realize. The function pointer structure is as follows:

because the aviation communication middleware works in the linux system, the Ethernet operation and the CAN bus operation are both based on the socket interface of the system. The Ethernet is based on a PF _ INET protocol family, the transmission protocol is UDP, the CAN bus operation is based on the PF _ CAN protocol family, and the transmission protocol is RAW.

The Init operation encapsulates the socket create operation.

Active encapsulates socket binding operations.

Stop modifies the state, setting the current middleware port to an unavailable state.

Release corresponds to the soket Release operation.

And after the Update correspondingly modifies the routing forwarding table, modifying the socket binding address, modifying the IP and PORT by Ethernet, and modifying the canID and the controller interface index by the canbus.

Send corresponds to packet sending operation and recv corresponds to packet receiving operation.

Route forwarding algorithm

The embodiment is mainly applied to the interior of an avionics system, the avionics system is a static system, all possible data paths in the system, data flow directions among all devices and physical connections are statically known. The system determines a route forwarding table on each device in the route management module according to the planned data path, and the table is also static.

Since devices directly connected via ethernet or CAN bus CAN be considered as connected two by two, routing forwarding mainly takes place between the CAN bus and the ethernet.

The forwarding rules in the routing forwarding table mainly include the following contents: global numbering of current forwarding rules; forwarding the data type; the destination middleware port address, from which local middleware port the message needs to be sent to reach the destination middleware port, the next hop middleware port address, and whether the current forwarding rule is normal or not.

In order to maintain the state of the forwarding rule, the aviation middleware periodically sends heartbeat messages to adjacent middleware ports involved in the forwarding rule to confirm the communication state between the aviation middleware ports and the adjacent aviation middleware ports.

Interface API and function of middleware

Mw _ init initializes the middleware.

The MW _ send sends a message interface, the address of the port of the local middleware and the address of the port of the destination middleware which participate in sending the message, and the content and the length of the sent data.

And the input parameter of the MW _ recv message receiving interface is the local middleware port address, and returns data and the source middleware port address corresponding to the data.

And the MW _ set _ opt modifies and sets static forwarding table information, and addresses the corresponding rule through the number of the forwarding rule.

And the MW _ get _ opt acquires the static forwarding table information and addresses the corresponding rule through the forwarding rule number.

All messages of the aviation middleware of the embodiment contain 4 bytes of source middleware port addresses and 4 bytes of destination middleware port addresses.

In the packet receiving process, after the middleware bus adaptation module reads out the message from the bus, the corresponding message is transmitted to the routing management module. The module performs the operations of:

1) analyzing information such as a destination middleware port address, a source middleware port address, a data type and the like in a message header;

2) confirming whether the destination middleware port is on the current equipment, if so, uploading the data to a caller of the middleware API function;

3) otherwise, searching the route forwarding table, the message of the specific data type and the destination middleware port address can only be sent from the specific middleware port, and after finding the forwarding rule, sending the message from the corresponding middleware port.

4) And if the routing rule can not be found in the routing forwarding table, discarding the corresponding message.

5) If a forwarding rule can be found but the rule status is not available and no other forwarding rule can be found that can route the data to the destination middleware port, the message is discarded.

In the process of sending the message, the middleware API function transmits the input parameter to the routing module, and the routing module executes the operation:

1) finding a middleware port for sending a message through a source middleware port address, and if the current equipment has no corresponding intermediate port, failing to send;

2) and searching a forwarding rule of a destination middleware port in the route forwarding table, and if the forwarding rule is not found, failing to send.

3) And if the forwarding rule is found, sending the message out from the corresponding middleware port.

4) If a forwarding rule is found but the rule status is not available and no other rule is found that can forward data to the destination middleware port, the forwarding fails.

The aviation communication middleware of the embodiment is provided in a mode of C language library file + C language header file, and a standard message receiving and sending interface is defined in the header file. The business program on the avionic device can call an aeronautical communication middleware interface only by linking the middleware library, so that the receiving and sending of data between devices connected by different physical buses are realized.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. The distributed aeronautical communication middleware simultaneously supports the CAN bus and the Ethernet, and is characterized in that the aeronautical communication middleware works under a linux system and realizes the control of a physical bus by depending on an interface provided by an operating system; the aviation communication middleware comprises a bus adaptation module, a routing management module and an interface API;

2. The distributed avionics middleware of claim 1 that supports both CAN bus and Ethernet, wherein both Ethernet operations and CAN bus operations are based on socket interfaces.

3. The distributed avionics communications middleware supporting both a CAN bus and Ethernet according to claim 1, wherein the avionics communications middleware employs a distributed architecture.

4. The distributed avionics communication middleware supporting both a CAN bus and Ethernet according to any of claims 1 to 3, wherein the avionics communication middleware port defines: within an ethernet network, each combination of IP plus ports is treated as a middleware port; on the CAN bus, each CAN bus controller plus CAN ID combination is treated as a middleware port.

5. The distributed avionics communication middleware supporting both a CAN bus and Ethernet according to claim 4, wherein the avionics communication middleware port is a linked list architecture comprising: next _ node, middleware port address addr, port type pt _ type, union type low _ Info, container pointer to current linked list, set of middleware port operation functions cmu _ ops, and lock pt _ lock.

6. The distributed avionics middleware supporting both a CAN bus and Ethernet according to claim 4 wherein operations on middleware ports are encapsulated as a structure of function pointers, wherein each pointer points to a corresponding function implementation, comprising: the Init operation encapsulates the socket creation operation; active packages socket binding operation, Stop modification state, Release operation corresponding to Release, modification of socket binding address after Update modifies routing forwarding table, Send corresponding packet sending operation and recv corresponding packet receiving operation.

7. The distributed avionics middleware support for both CAN bus and Ethernet according to claim 4 wherein the forwarding rules for the route forwarding tables on each device in the avionics system comprise: the global number of the current forwarding rule, the type of the forwarding data, the port address of the destination middleware, which local middleware port needs to send a message to reach the destination middleware port, the port address of the next hop middleware, and whether the current forwarding rule is normal or not.

8. The distributed avionics communications middleware supporting both a CAN bus and Ethernet according to claim 4, wherein the interface API comprises: initializing a middleware function Mw _ init, sending a message interface function MW _ send, receiving a message interface function MW _ recv, modifying and setting a static forwarding table information function MW _ set _ opt, and acquiring the static forwarding table information function MW _ get _ opt.

9. The message receiving method of the aeronautical communication middleware of any one of claims 1-8, wherein after the bus adaptation module reads the message from the bus, the corresponding message is transmitted to the route management module, and the route management module performs the following operations:

10. The method for sending the message of the aeronautical communication middleware of any one of claims 1 to 8, wherein during the message sending process, the interface API passes the incoming reference to the route management module, and the route management module performs the following operations: