JP5051657B2 - Communication control device - Google Patents

Description

  The present invention relates to a communication control apparatus that transmits and receives data.

  In a communication control device that transmits and receives data, received data and transmitted data are temporarily stored in a buffer, and the buffer is provided by a hierarchical structure designed based on the concept of an OSI (Open System Interconnection) reference model. The received data is analyzed and the transmitted data is assembled. An example of buffer management technology in this type of communication control apparatus is described in Patent Document 1 and Patent Document 2.

Referring to FIG. 5, according to the technique described in Patent Document 1 (hereinafter referred to as related technique 1), the transmission process is performed according to the procedure shown in FIGS. First, the N + 1 layer, which is the highest layer, stores the generated data a in the buffer B, and notifies the N layer of the start address p ₁ and the buffer length n ₁ (A). Next, the N layer assembles the data b before the data a on the buffer B, and notifies the N−1 layer of the start address p ₂ and the buffer length n ₂ (b). Next, the N-1 layer assembles the data c before the data b on the buffer B, and notifies the P layer of the start address p ₃ and the buffer length n ₃ . Finally, the P layer sends data corresponding to the buffer length n ₃ from the head address p ₃ to the communication line (c).

According to Related Art 1, the reception process is performed according to the procedure shown in FIGS. First, the P layer receives data from the communication line, stores it in the buffer B, and notifies the N-1 layer of the head address q ₃ and the buffer length n ₃ (d). Next, the N-1 layer receives the data c on the buffer B and notifies the N layer of the start address q ₂ and the buffer length n ₂ (e). Next, the N layer receives the data b on the buffer B and notifies the N + 1 layer of the head address q ₁ and the buffer length n ₁ . The N + 1 layer receives the data a on the buffer B (f).

  On the other hand, according to the technique described in Patent Document 2 (hereinafter referred to as related technique 2), transmission processing is performed in the following procedure. First, the protocol to be used is selected for each layer corresponding to the type of transmission data and the transmission destination. For example, there are three layers a, b, and c in order from the lower layer, the layer a has three types of protocols A to C, the layer b has three types of protocols D to F, and the layer c has G to G In the case where there are three types of protocols I, it is assumed that A is selected as the protocol for layer a, D is selected as the protocol for layer b, and G is selected as the protocol for layer c. Next, based on the selected protocols A, D and G, the total amount of protocol headers used is calculated. Next, in addition to the transmission data storage area, a buffer having a header storage area corresponding to the total amount of the calculated protocol header is secured, and the transmission data is stored in the transmission data storage area. Next, control is transferred to the protocol G, and the header of the protocol G is stored before the transmission data on the buffer. Next, control is transferred to protocol D, and the header of protocol D is stored before the header of protocol G on the buffer. Next, control is transferred to protocol A, and the header of protocol A is stored before the header of protocol D on the buffer. Finally, the data on the buffer is sent to the communication line.

JP-A-6-244902 JP 7-250124 A

  According to Related Art 1, data handled in each layer is interfaced by a head address and a buffer length. For this reason, a data buffer is provided for each layer, the data received in response to the transfer request is taken in, the necessary data is added and transferred to the next layer, and the processing becomes faster and the memory area is saved. be able to. However, in Related Art 1, at the time of transmission, a process for securing an area for adding data before data on the previous layer is required.

  On the other hand, according to the related technique 2, since a buffer including an area corresponding to the total header amount is secured at the time of transmission, the problem in the related technique 1 is solved, and the efficiency of the transmission process is improved.

  However, neither the related technique 1 nor the related technique 2 has the idea of sharing the buffer at the time of transmission and at the time of reception. Therefore, in one communication control apparatus, when data received from a certain communication line is referred or updated by an application and transmitted to another place through another communication line, a process for securing a buffer for storing received data and transmission The securing process twice with the securing process of the buffer for storing data was necessary.

  The present invention has been proposed in view of such circumstances, and an object of the present invention is to provide a buffer securing process in a communication control apparatus that refers to or updates data received from a certain communication line and transmits the data to another communication line. It is to reduce the number of times.

  The communication control apparatus of the present invention is a communication control apparatus that refers to or updates data received from a first line by a first communication controller and transmits the data to a second line by a second communication controller, When receiving data from the first line by the first communication controller, it is used for both storing received data and storing transmission data to be transmitted to the second line by referring to or updating the received data. Reserve a buffer in memory.

  According to the present invention, at the time of data reception, a buffer is allocated in order to secure a buffer on the memory that is used for both storing received data and storing transmitted data that is transmitted to another line by referring to or updating the stored received data. It becomes possible to reduce the number of times of processing. Further, the number of buffer securing processes is reduced, so that the speed of communication processing is improved, and the power consumption of the communication control apparatus can be reduced by reducing the processing amount.

[First Embodiment]
Referring to FIG. 1, a communication control apparatus 100 according to the first embodiment of the present invention includes a CPU 10, a ROM 20, a RAM 30, and two types of communication controllers 40 and 50 connected to each other via a bus 60. Yes.

  The ROM 20 stores a program executed by the CPU 10 of the communication control apparatus 100 and fixed data. The RAM 30 stores a buffer for storing transmission / reception data and variable data.

  The communication controller 40 is a component that receives data from the communication line 41 and transmits data to the communication line 41. Similarly, the communication controller 50 is a component that receives data from the communication line 51 and transmits data to the communication line 51. In this embodiment, the communication controller 40 is an Ethernet (registered trademark) controller, and the communication controller 50 is a serial port controller.

  The CPU 10 is a component that performs the main control of the communication control apparatus 100. As functional means related to communication control, two types of communication driver processing units 11, 12, a communication protocol processing unit 13, and a communication application unit 14 are provided. It has. These can be realized by a program stored in the ROM 20, for example.

  The communication driver processing unit 11 is a communication driver for the communication controller 40, and the communication driver processing unit 12 is a communication driver for the communication controller 50.

  The communication protocol processing unit 13 is a protocol stack as communication middleware. In the case of the present embodiment, the communication protocol processing unit 13 includes an L2 processing unit 15 and an L3 processing unit 16. The L2 processing unit 15 is a part that manages processing related to the data link layer of L2 (layer 2), that is, the OSI reference model, and the L3 processing unit 16 performs processing related to L3 (layer 3), that is, processing related to the network layer of the OSI reference model. It is the part that governs.

  The communication application unit 14 is a part that performs processing related to the layers above the transport layer of the OSI reference model. In the case of the present embodiment, the communication application unit 14 includes an L4 (layer 4), that is, an L4 processing unit 17 that controls processing related to the transport layer, and an application that controls processing related to layers from the session layer to the application layer of the OSI reference model. Part 18.

  The communication control apparatus 100 according to the present embodiment functions as a communication adapter apparatus that refers to or updates the data received from the communication line 41 by the communication controller 40 in the application unit 18 and transmits the data to the communication line 51 by the communication controller 50. In addition, a plurality of communication protocols are defined in each of the layers L2 to L4 as shown in FIG. 2, and one communication protocol is selected from a plurality of communication protocols and applied when actually transmitting / receiving data. Is done.

  Next, the operation of this embodiment when data received from the communication line 41 is referred to or updated by the application unit 18 and transmitted to the communication line 51 will be described.

  Referring to FIG. 3, when the communication controller 40 detects an Ethernet frame addressed to the own communication control device on the communication line 41, the communication controller 40 receives the frame and notifies the CPU 10 by an interrupt. The CPU 10 activates the communication driver processing unit 11 in response to this interruption.

  The communication driver processing unit 11 secures a buffer BUF for storing a frame received by the communication controller 40 in an empty area of the RAM 30, and stores received data (received frame) in the buffer BUF. The buffer BUF secured at this time is used not only for storing received data but also for storing transmission data when the received data is referred to or updated and transmitted to the communication line 51. If it is guaranteed that the size of the transmission data does not exceed the size of the reception data, the size of the buffer BUF to be secured may be determined in consideration of only the size of the reception data. However, if the total protocol header size of the transmission data exceeds the total size of the protocol header of the reception data as a result of the difference in the protocol used in each layer between reception and transmission, at least the buffer BUF that is larger in size than the total size of the protocol header of the reception data It is necessary to secure. When the payload size increases as a result of the application unit 18 updating the payload of the L4 layer, it is necessary to secure a buffer BUF having a size that takes into account the increase due to the payload in addition to the increase due to the protocol header. is there. The communication driver processing unit 11 has a function of determining the size of the buffer BUF to be secured based on these matters. Although the details of this function will be described later, it is assumed that the buffer BUF shown in FIG.

In the buffer BUF shown in FIG. 4, areas from addresses a ₀ to a ₁ of the RAM 30 are allocated. The buffer BUF includes a forward spare area size n ₀ from the address a ₀ to the address a _2, and the size n ₂ of the data storage area from the address a ₂ to address a _6, the address a ₆ to address a ₁ Are logically divided into rear spare areas of size n ₁ . The data storage area is an area for storing received data. The forward spare area is an extension area used when the total size of the protocol header of the transmission data becomes larger than that of the reception data, and the rear spare area is an extension area used when the size of the payload is enlarged by updating. .

The communication driver processing unit 11 stores the received data in the data storage area of the buffer BUF, as shown in FIG. 4, and stores the start address a ₂ of the data storage area and the received data length (= size n _{2 of the} data storage area). The L2 processing unit 15 of the communication protocol processing unit 13 is notified. As shown in FIG. 4, the received data is composed of a payload, an L4 header attached in front of it, an L3 header attached in front of it, and an L2 header attached in front of it.

L2 processing unit 15 identifies the protocol being applied to the L2 analyzes the notified address a ₂ L2 header stored since in the buffer BUF, performs processing according to that protocol. Then, the L2 processing unit 15 notifies the L3 processing unit 16 of the start address a ₃ of the L3 header and the data length n ₃ of L3.

L3 processor 16 identifies the protocol being applied to the L3 analyzes the notified address a ₃ L3 header stored since in the buffer BUF, performs processing according to that protocol. Then, the L3 processing unit 16 notifies the L4 processing unit 17 of the communication application unit 14 of the start address a ₄ of the L4 header and the data length n ₄ of L4.

L4 processing section 17 identifies a protocol being applied to L4 header stored in the notified address a ₄ later in the buffer BUF to L4 analyzes and executes the processing according to that protocol. Then, the L4 processing unit 17 notifies the application unit 18 of the leading address a ₅ and the data length n ₅ of the payload.

Application unit 18 refers to or updates the payload stored in the notified address a ₅ or later on the buffer BUF. The purpose of referring to the payload is, for example, to identify the type of data in the payload and the transmission destination. The purpose of updating the payload is, for example, to convert the data format to another format or to change the transmission destination. Since data format conversion is performed at the character code level, the size of the payload may be changed. In addition, when the transmission destination is described in the SIP-URI, the SIP-URI is rewritten at the character code level, so that the size of the payload may be changed.

When the received payload is updated, the application unit 18 overwrites the area after the address a ₅ of the buffer BUF, that is, the original payload part, as the payload to be included in the transmission data. FIG. 4 shows an example in which the payload included in the transmission data is stored in the area from the address a ₅ to the address a ₇ of the buffer BUF. In the case where the reference not only to update, because the original payload is stored in the address a ₅ subsequent buffer BUF, used as a payload to include it as the transmission data.

  Next, the application unit 18 determines a protocol to be used in each layer of L4, L3, and L2 based on the type of transmission data and the transmission destination. Here, for convenience of explanation, it is assumed that L4 is determined as the protocol G, L3 is determined as the protocol D, and L2 is determined as the protocol A. The determined protocol information is stored in, for example, a predetermined area of the RAM 30, and is referred to by the L4 processing unit 17, the L3 processing unit 16, and the L2 processing unit 15.

Next, the application unit 18 notifies the L4 processing unit 17 of the leading address a ₅ and the data length n ′ _{5 of} the payload.

Then L4 processing section 17 writes the L4 header protocol G before the payload stored in the notified address a ₅ or later on the buffer BUF, the start address a ₈ to L4 header is written and data length n _'4 Is sent to the L3 processing unit 16 of the communication protocol processing unit 13.

Next L3 processor 16 writes the L3 header protocol D before the L4 header stored in notified address a ₈ later in the buffer BUF, the start address a ₉ of L3 header is written and data length n ' ₃ is notified to the L2 processing unit 15.

Then L2 processing unit 15 writes the L2 header of protocol A before the L3 header stored in notified address a ₉ later in the buffer BUF, the start address of the L2 header writing a ₁₀ and the data length n ' ₂ is notified to the communication driver processing unit 12 of the communication controller 50 that handles the protocol A.

Next, the communication driver processing unit 12 reads the L2 data stored after the notified address a ₁₀ on the buffer BUF, and transmits it to the communication controller 50. The communication controller 50 transmits the received data to the communication line 51. When the transmission by the communication controller 50 is completed, the communication driver processing unit 11 releases the buffer BUF that stores the transmission data.

Next, a method for determining the sizes n ₀ , n ₁ , and n ₂ of the buffer BUF of FIG. 4 shared by received data and transmitted data will be described with some examples.

(1) Method for determining the size n ₂ of the data storage area of the buffer BUF Since the size n ₂ is the size of the data storage area for storing the received data, it is determined based on the size of the received data. For example, the size n ₂ is a value equal to the size of the received data.

(2) Method of determining the size n ₀ of the front spare area of the buffer BUF The size n ₀ is the size of the front spare area used when the total size of the protocol header of the transmission data becomes larger than that of the received data. , Based on the difference in the total size of the protocol headers of the transmission data and the reception data. Specific methods include the following methods.

(2-1) Example 1
X is the total protocol header size of the communication protocol with the largest total protocol header size among the communication protocol combinations at the time of transmission, and the total protocol header size used is the largest among the communication protocol combinations at the time of reception. When the total size of the protocol headers of the small communication protocol is Y, XY is the size n ₀ of the front spare area. According to this method, the total size of the L2 to L4 headers of the actual reception data communication protocol is equal to the minimum value Y, and the total size of the L2 to L4 headers of the actual transmission data communication protocol is the maximum value. If it is equal to X, all of the front spare area size n ₀ will be used, otherwise a part of the front spare area will be used or not used at all. Although some waste occurs in terms of the amount of buffer used, if XY is calculated in advance and stored as fixed data in the ROM 20 or the like, it is only necessary to refer to it, so the processing amount is reduced.

(2-2) Example 2
The communication driver processing unit 11 specifies a part or all of the combination of communication protocols used in the received data, and the total size of the protocol header used among the combinations of the specified protocol and the remaining layer protocols. Is Y ′, the total size of the protocol headers of the communication protocol that maximizes XY is the size n ₀ of the front spare area. Here, X is the total size of the protocol header of the communication protocol having the largest total size of the protocol header used in the combination of communication protocols at the time of transmission, as in X in Example 1.

  As a method for the communication driver processing unit 11 to specify a part of the combination of communication protocols used in the received data, for example, the communication driver processing unit 11 is used in L2 depending on the type of the communication controller 40 that interrupted when receiving data. There is a method for specifying the protocol to be any one or two of the protocols A to C. In addition, there is a method in which the communication driver processing unit 11 directly refers to received data held in the communication controller 40 and analyzes each header such as an L2 header to identify a protocol used.

(3) Method of determining the size n ₁ of the rear spare area of the buffer BUF The size n ₁ is the size of the rear spare area used when the size of the payload is enlarged by updating. It is determined based on the presence / absence and the maximum increment when updating. That is, if the application unit 18 does not update the payload, the size n ₁ of the rear spare area is zero. Further, if the maximum increase width assumed when updating is Δd, the size n ₁ of the rear spare area is Δd.

  Next, the effect of this embodiment will be described.

  According to the present embodiment, the same buffer BUF can be used for reception and transmission in the communication control apparatus 100 that references or updates the data received from the communication line 41 and transmits the data to the other through the communication line 51. As a result, the number of buffer securing processes can be reduced by half. By reducing the number of buffer securing processes by half, the speed of communication processing is improved, and at the same time, the power consumption of the communication control apparatus 100 can be reduced by reducing the processing amount.

[Other embodiments]
In the above embodiment, the data received from the communication line 41 is referred to or updated by the application unit 18 and transmitted to the communication line 51. Conversely, the data received from the communication line 51 is referred to by the application unit 18 or An embodiment in which it is updated and transmitted to the communication line 41 is also conceivable. In this case, the communication driver processing unit 12 has a buffer acquisition function similar to that of the communication driver processing unit 11.

  In the above embodiment, the Ethernet controller and the serial port controller are used as the communication controller. However, the communication controller in the present invention is not limited to these types, and other types such as token ring and X.25 are used. It may be a type of communication controller.

  In the above embodiment, only two types of communication controllers are provided, but three or more types of communication controllers may be provided.

  In the above embodiment, a hierarchical structure having three layers L2, L3, and L4 is taken as an example of the upper layer of the physical layer. However, any hierarchical structure designed based on the concept of the OSI reference model can be applied. Is possible.

It is a block diagram of a 1st embodiment of the present invention. It is a figure which shows the communication protocol which can be used in each layer in the 1st Embodiment of this invention. It is operation | movement explanatory drawing of the 1st Embodiment of this invention. It is explanatory drawing of the buffer in the 1st Embodiment of this invention. It is explanatory drawing of the related technology of this invention.

Explanation of symbols

10 ... CPU
DESCRIPTION OF SYMBOLS 11, 12 ... Communication driver process part 13 ... Communication protocol process part 14 ... Communication application part 15 ... L2 process part 16 ... L3 process part 17 ... L4 process part 18 ... Application part 20 ... ROM
30 ... RAM
40, 50 ... communication controllers 41, 42 ... communication line 60 ... bus 100 ... communication control device

Claims (6)

When receiving data from the first line by the first communication controller, a buffer for storing received data and storing transmission data is secured on the memory, and the received data is stored in the secured buffer, A receiving side driver processing unit that delivers the start address and data length of the received data;
Receives the leading address and data length of the received data from the receiving side driver processing unit, recognizes the protocol header of each layer in the received data on the buffer in order from the lower layer, and starts the upper address of the upper layer data And a communication protocol processing unit on the receiving side that delivers the data length,
Receives the top address and data length of the upper layer data from the receiving side communication protocol processing unit, recognizes and references or updates the upper layer protocol header and payload on the buffer, and starts the top layer data head A communication application section that delivers the address and data length;
The top address and data length of the upper layer data are received from the communication application unit, and the protocol header of that layer is changed to the protocol header of the upper layer on the buffer in order from the lower layer of the upper layer. A transmission-side protocol processing unit that stores the leading address of the transmission data and the data length,
A transmission side driver processing unit that receives a start address and a data length of the transmission data from the transmission side protocol processing unit, reads the transmission data from the buffer, and transmits the transmission data to a second line by a second communication controller; ,
The buffer includes a data storage area for storing the reception data, a front spare area used when the total size of the protocol header of the transmission data is larger than the total size of the protocol header of the reception data, and the reception data The communication control device is configured with a rear spare area used when the size of the payload included in is expanded by updating . The size of the front spare area is used in the combination of communication protocols on the receiving side from the total size of the protocol header of the communication protocol having the largest total size of the protocol header used in the combination of communication protocols on the transmitting side. 2. The communication control apparatus according to claim 1 , wherein the total size of the protocol header is set to be equal to or larger than a value obtained by subtracting the total size of the protocol header of the communication protocol having the smallest size. Identify at least a part of a combination of communication protocols used in the received data, and select a communication protocol that maximizes the total size of protocol headers used in the combination of the specified protocol and the remaining layer protocol. When the total size of the protocol header is Y ′ and the total size of the protocol header of the communication protocol having the largest total protocol header size among the combinations of communication protocols on the transmitting side is X, X−Y ′ is the front. the communication control device according to claim 1 or 2, characterized in that the size of the spare area. Size of the backward spare area, the communication control device according to any one of claims 1 to 3, characterized in that it is determined based on a maximum increment of payload that is assumed to be applied to update . A communication control method executed by a communication control device having a reception side driver processing unit, a reception side communication protocol processing unit, a communication application unit, a transmission side protocol processing unit, and a transmission side driver processing unit,
A data storage for storing the reception data, wherein the reception side driver processing unit is a buffer that is used for both reception data storage and transmission data storage when the first communication controller receives data from the first line. The area, the forward spare area used when the total size of the protocol header of the transmission data is larger than the total size of the protocol header of the reception data, and the size of the payload included in the reception data is expanded by updating A buffer composed of a rear spare area to be used in the memory is secured on the memory, the received data is stored in the secured buffer, and a head address and a data length of the received data are delivered,
The receiving side communication protocol processing unit receives the start address and data length of the received data from the receiving side driver processing unit, and recognizes the protocol header of each layer in the received data on the buffer in order from the lower layer. Pass the top address and data length of the upper layer data,
The communication application unit receives a top address and a data length of the upper layer data from the receiving side communication protocol processing unit, recognizes an upper layer protocol header and payload on the buffer, refers to or updates, and Deliver the top address and data length of the upper layer data,
The transmission-side protocol processing unit receives a head address and a data length of the upper layer data from the communication application unit, and in order from the layer immediately below the upper layer, the protocol header of the layer is displayed on the buffer. Store before the protocol header of the layer above, and pass the start address and data length of the transmission data,
The transmission side driver processing unit receives the start address and data length of the transmission data from the transmission side protocol processing unit, reads the transmission data from the buffer, and transmits the transmission data to the second line by the second communication controller.
Communication control method. Computer
A buffer that is used for both reception data storage and transmission data storage when receiving data from the first line by the first communication controller, a data storage area for storing the reception data, and a protocol for the transmission data A front spare area used when the total header size becomes larger than the total protocol header size of the received data, and a rear spare area used when the payload size included in the received data is enlarged by updating. A buffer configured in the memory, receiving the received data in the secured buffer, and receiving side driver processing unit that delivers the start address and data length of the received data;
Receives the leading address and data length of the received data from the receiving side driver processing unit, recognizes the protocol header of each layer in the received data on the buffer in order from the lower layer, and starts the upper address of the upper layer data And a communication protocol processing unit on the receiving side that delivers the data length,
Receives the top address and data length of the upper layer data from the receiving side communication protocol processing unit, recognizes and references or updates the upper layer protocol header and payload on the buffer, and starts the top layer data head A communication application section that delivers the address and data length;
The top address and data length of the upper layer data are received from the communication application unit, and the protocol header of that layer is changed to the protocol header of the upper layer on the buffer in order from the lower layer of the upper layer. A transmission-side protocol processing unit that stores the leading address of the transmission data and the data length,
A transmission side driver processing unit that receives a start address and a data length of the transmission data from the transmission side protocol processing unit, reads the transmission data from the buffer, and transmits the transmission data to a second line by a second communication controller;
Program to make it function.

Images