JP2011072030A - Method and apparatus for stream data communication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for stream data communication, which achieves efficient consumption of a bus band and a processing load of a processor, by transmitting and receiving data without generating data copies involving check sum calculation between an application program and a protocol stack. <P>SOLUTION: In the apparatus for stream data communication, a check sum value is calculated using a check sum calculation module 115, and a memory used by the application program and the protocol stack is held in common. When transmitting data, the data to be transmitted, which are prepared by the application program, are transmitted by indicating to a communication interface 113 without copying the data by the protocol stack, and when receiving data, the application program uses the data received by the communication interface 113 via a network without copying the data by the protocol stack. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a stream data communication method and a stream data communication apparatus, and is particularly effective when applied to the prevention of waste of bus bandwidth and the waste of processor processing load using a checksum calculation module and a socket-like protocol stack. It is about technology.

  Recently, not only PCs (Personal Computers) but also various embedded devices including AV (Audio / Visual) devices such as video recorders have been equipped with communication functions. Typical physical interface and data link layer protocol standards related to communication functions adopted by these devices include Ethernet (registered trademark) and IEEE (Institut of Electrical and Electronic Engineers) 802.3 wired LAN (Local Area Network). ) Standard and IEEE 802.11 wireless LAN standard. As a network layer protocol, there is an IP (Internet Protocol) standard defined by RFC (Request For Comments) 791 by IAB (Internet Architecture Board), and a TCP (defined by RFC 791 as a transport layer protocol). There are a Transmission Control Protocol (UDP) standard and a UDP (User Datagram Protocol) standard defined in RFC768.

  A network control software group having functions such as a network layer protocol and a transport layer protocol is generally referred to as a protocol stack, and the protocol stack differs depending on an OS (Operating System) adopted by these devices. For example, a UNIX (registered trademark) OS often has a standard protocol stack in the kernel. On the other hand, for OSs that do not support communication as a standard, protocol stack products for providing communication functions to the OSs are often sold and provided to communication device developers and manufacturers. . For this reason, it has become relatively difficult to develop and manufacture a device having a communication function conforming to a standard combining various protocol functions having various specifications.

  As typical API (Application Program Interface) specifications of the protocol stack, there are sockets shown in Non-Patent Document 1 and Non-Patent Document 2.

  FIG. 10 is a diagram showing an API function call order of TCP protocol communication in a protocol stack having a typical socket API specification, and FIG. 11 is a diagram of UDP protocol communication in a protocol stack having a typical socket API specification. It is a figure which shows API function call order. In both figures, the right half shows the server side, and the left half shows the client side. Although the functions shown in these figures are general notations, other general notations may be expressed as send functions instead of write functions 1006, and may be expressed as recv functions instead of read functions 1005. There is also.

  The socket function 1001 generates a socket having attributes such as TCP protocol communication / UDP protocol communication and server / client. The bind function 1002 gives an attribute such as a port number to the socket. The listen function 1003 waits for a connection from a communication partner. The connect function 1011 requests connection to the communication partner. The accept function 1004 accepts a connection from a communication partner. A write function 1006 and a sendto function 1106 send data to the communication partner, while a read function 1005 and a recvfrom function 1105 receive data from the communication partner. A close function 1007 closes the socket.

  With regard to the protocol stack having the socket API specification and the operation of the application program using the TCP at the time of data transmission by TCP, the specification of the communication partner and the procedure for establishing / disconnecting the connection are omitted, and the flow of transmission data (write function 1006 in particular) The following transmission steps 1 to 5 will be described with a focus on the details of the operation of (1).

  [Transmission Step 1] The application program stores (preparation) data to be transmitted in the first memory area secured by the application program itself (using the memory management function of the OS).

  [Transmission Step 2] The application program calls the write function 1006 to instruct transmission while designating the first memory area for the protocol stack.

  [Transmission Step 3] The protocol stack copies the data in the first memory area designated by the application program to the second memory area secured by the protocol stack itself (using the memory management function of the OS). Calculate the checksum value of the data. Here, the calculation of the checksum value can be performed simultaneously with the copy because the target data is the same.

  [Transmission Step 4] The protocol stack generates a protocol header such as a TCP header using the obtained checksum value.

  [Transmission Step 5] The protocol stack transmits the data in the second memory area together with the generated protocol header to the communication partner.

  In addition, the protocol stack having the socket API specification and the operation of the application program using the socket when receiving data by TCP are omitted for the specification of the communication partner and the procedure for establishing / disconnecting the connection. The following receiving steps 1 to 5 will be described with a focus on the details of the function 1005.

  [Reception Step 1] The protocol stack stores the received data from the communication partner in the third memory area secured by the protocol stack itself (using the memory management function of the OS).

  [Reception Step 2] The application program calls the read function 1005 to instruct to receive the protocol stack while designating the reserved fourth memory area (using the memory management function of the OS).

  [Reception Step 3] The protocol stack copies the data in the third memory area to the fourth memory area designated by the application program, and further calculates the checksum value of the data. Here, the calculation of the checksum value can be performed simultaneously with the copy because the target data is the same.

  [Reception Step 4] When the protocol stack confirms that the obtained checksum value matches the checksum value included in the received TCP header, the protocol stack notifies the application program.

  [Reception Step 5] The application program uses the data in the fourth memory area.

  It should be noted that the reception steps 1 and 2 may be changed depending on the arrival timing of the received data from the communication partner in the function of the protocol stack having the above socket API specifications and the application program using the socket when receiving data by TCP. is there.

  As described above, when transmitting / receiving data, an application program using a protocol stack having a socket API specification calls a transmission function while specifying a memory area in which prepared transmission data is stored, or receives received data to be used later. It is only necessary to call the reception function while specifying the memory area to be stored. For this reason, the protocol stack having the socket API specification has been completed as a system that requires little burden and consideration on application programs, and is widely used regardless of the type of device or OS.

“Test Page. Yoshifumi Tanaka”, [online], [October 11, 2005 search], Internet <URL: http: // kansai. anesth. or. jp / gijutu / c ++ / man-socket. php> Michael J.M. Donahoo, Kenneth L. Co-authored by Calvert, translated by Tomohiro Kodaka, “TCP / IP Socket Programming C Language”, Ohmsha, 2003

  However, in the protocol stack of the socket API specification described above, the application program secures from the memory area secured by the protocol stack to the memory area secured by the protocol stack when data is transmitted, and from the memory area secured by the protocol stack when data is received. Data copy with checksum calculation occurs in the selected memory area. As a result, there is a problem that the bus bandwidth through which the data flows is wasted and the processing load of the processor that performs the processing is wasted.

  Therefore, an object of the present invention is to transmit and receive data without accompanying checksum calculation between an application program and a protocol stack, thereby improving the efficiency of bus bandwidth consumption and the efficiency of processor processing load consumption. It is an object to provide a stream data communication method and a stream data communication apparatus that achieve the above.

  In the stream data communication method and the stream data communication apparatus of the present invention, the stream data communication method has a checksum calculation module, and includes a stream interface to which stream data is input, a communication interface for transmitting stream data, an application program, and a protocol stack. A memory for storing the program to be stored, and a processor for processing the program, calculate the checksum value using the checksum calculation module, share the memory used by the application program and the protocol stack, and transmit the application The protocol stack sends data prepared by the program to the communication interface without copying, and when receiving, the communication interface receives it via the network. The most important feature that the application program is utilized without a data protocol stack copy.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  According to the present invention, data can be transmitted and received without generating a checksum calculation between the application program and the protocol stack, so that the bus bandwidth can be consumed more efficiently and the processor processing load can be consumed more efficiently. There is an advantage to achieve.

It is a block diagram which shows the structure of the stream data communication apparatus which concerns on Embodiment 1 of this invention. It is a flowchart which shows the stream data communication method of the stream data communication apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the data arrangement | positioning in memory in the case of transmitting stream data in the stream data communication method of the stream data communication apparatus which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of the stream data communication apparatus which concerns on Embodiment 2 of this invention. It is a flowchart which shows the stream data communication method of the stream data communication apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows the data arrangement | positioning in memory in the case of receiving stream data in the stream data communication method of the stream data communication apparatus which concerns on Embodiment 2 of this invention. It is a block diagram which shows the structure of the stream data communication apparatus which concerns on Embodiment 3 of this invention. It is a flowchart which shows the stream data communication method of the stream data communication apparatus which concerns on Embodiment 3 of this invention. It is a flowchart which shows the stream data communication method of the stream data communication apparatus which concerns on Embodiment 3 of this invention. It is a figure which shows the API function call order of TCP protocol communication in the protocol stack which has a typical socket API specification. It is a figure which shows the API function call order of UDP protocol communication in the protocol stack which has a typical socket API specification.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

(Embodiment 1)
<Configuration of stream data communication apparatus>
The configuration of the stream data communication apparatus according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a configuration diagram showing a configuration of a stream data communication apparatus according to Embodiment 1 of the present invention, which is a configuration for transmitting stream data.

  In FIG. 1, a stream data communication apparatus 101 includes a processor 111 that performs data processing such as various data calculations and determinations, a memory 112 that stores data, a communication interface 113 that transmits and receives data, and a stream data A stream interface 114 for inputting and outputting is provided. The processor 111, the memory 112, the communication interface 113, and the stream interface 114 are connected via an internal bus 116.

  Each of the processor 111, the communication interface 113, and the stream interface 114 leads the internal bus 116 (is a bus master) particularly for access to the memory 112. The stream interface 114 includes a checksum calculation module 115 that performs checksum calculation.

  Further, the stream data communication apparatus 101 is connected to a network 122 such as a LAN or the Internet via a communication cable 121 connected to a communication interface 113. There is a communication partner (not shown) in the network 122, and the stream data communication apparatus 101 is in a state where it can communicate with the communication partner.

  Further, the stream data communication apparatus 101 is connected to the streamer 132 via the external bus 131. The streamer 132 obtains stream data stored in the storage device from a storage device (not shown), stores stream data in the storage device, or receives stream data from a tuner (not shown). Alternatively, the stream data can be processed to generate video data and audio data, and the video data can be sent to a display (not shown) and the audio data can be sent to a speaker (not shown). The stream data communication apparatus 101 receives stream data from the streamer 132 and outputs the stream data to the streamer 132.

<Stream Data Communication Method of Stream Data Communication Device>
Next, the stream data communication method of the stream data communication apparatus according to Embodiment 1 of the present invention will be described with reference to FIG. 2 and FIG. FIG. 2 is a flowchart showing the stream data communication method of the stream data communication apparatus according to Embodiment 1 of the present invention, and shows the operation when transmitting stream data. FIG. 3 is a diagram showing a data arrangement in the memory when stream data is transmitted in the stream data communication method of the stream data communication apparatus according to Embodiment 1 of the present invention.

  First, the processor 111 operates according to three types of programs stored in the memory 112, that is, an application program 301, a protocol stack 302, and an OS (kernel) (not shown).

  Hereinafter, the operation of the stream data communication apparatus 101 in the case of transmitting stream data using a program (the application program 301 or the protocol stack 302) being processed by the processor 111 as a word instead of the word “processor 111” will be described.

  First, in step 1 (201), the application program 301 calculates the checksum value of the stream data input from the streamer 132 to the stream interface 114 and stores the stream data in the first memory area 311. I will tell you. Accordingly, the stream interface 114 stores the stream data in the first memory area 311 while calculating the checksum value of the input stream data using the checksum calculation module 115.

  Next, in step 2 (202), the application program 301 specifies the checksum value calculated by the checksum calculation module 115 and the first memory area 311 in step 1 (201) for the protocol stack 302. To send.

  That is, the application program 301 designates the checksum value calculated by the checksum calculation module 115 and the first memory area 311 in step 1 (201), and transmits the protocol stack 302 as the next process of the processor 111. Move to.

  Next, in step 3 (203), the protocol stack 302 that has received the instruction uses the specified checksum value to provide the stream data stored in the specified first memory area 311 for communication. Data (protocol header) is generated and stored in the second memory area 312.

  In general, the protocol header is, for example, a MAC (Media Access Control) header, an IP header, and a TCP header in the case of communication using the TCP protocol, and a MAC header and an IP header in the case of communication using the UDP protocol, for example. It is a UDP header. In the case of communication using the IPv6 protocol, these IP headers are actually IPv6 headers.

  The TCP header is essential, the UDP header is selectable, and there is a portion that stores data to be transmitted and a checksum value of a part of the components of the protocol header (port number and the like). In step 3 (203), the specified checksum value is used to check the value and a part of the constituent elements of the protocol header without reading the data stored in the specified first memory area 311. The sum value is calculated and used as the checksum value stored in the TCP header or UDP header.

  Next, in step 4 (204), the protocol stack 302 transmits the data stored in the second memory area 312 and the first memory area 311 to the communication interface 113 as a series of transmission data. I will tell you. As a result, the communication interface 113 converts each data stored in the designated second memory area 312 and first memory area 311 as a series of transmission data to the communication cable 121, and hence the network 122, and thus to the communication partner. And send.

  Next, when recognizing the completion of transmission, the protocol stack 302 informs the application program 301 that transmission has been completed in step 5 (205).

  Finally, in step 5 (205), after the application program 301 knows that the transmission has been completed, the application program 301 releases the first memory area 311 (using the memory management function of the OS) or uses it for another purpose. It is possible to re-store other data using the data, or it is possible to restart from step 1 (201) and re-store the stream data to be transmitted next in the first memory area 311.

  Conversely, before knowing the completion of transmission, the application program 301 is restricted from releasing or re-storing the first memory area 311. If the stream data stored in the first memory area 311 is destroyed before transmission from the communication interface 113 or before confirmation of a reception response from the communication partner, the stream to be transmitted as intended by the application program 301 This is because data cannot be transmitted or retransmitted.

  However, the above-described transmission completion is not limited to the meaning that the reception side has received normally, and in communication that does not require provision of reliability, for example, the communication cable 113 is transmitting while the communication interface 113 is transmitting. It is also possible to regard a transmission error due to the collision of signals as transmission completion.

  In the above description, the basic flow in which the application program 301 transmits single stream data as single transmission data has been described, but the stream data communication method is not limited to this.

  For example, in step 1 (201), the application program 301 instructs each stream data to be stored in each of a plurality of memory areas while calculating the checksum value of each sequentially input stream data. 202), the application program 301 designates a memory area corresponding to each checksum value and instructs transmission thereof. In step 3 (203), the protocol stack 302 generates a corresponding protocol header. In (204), the protocol stack 302 instructs transmission while designating each of a series of data including the respective protocol headers and corresponding stream data. In step 5 (205), the protocol stack 302 02 informs from those completed transmission, implementations are possible and the like.

  In the above description, in step 2 (202), the application program 301 informs the protocol stack 302 of the checksum value. However, this is not an explicit one, and an implicit implementation is possible. That is, for example, in step 1 (201), the stream interface 114 may store the checksum value calculated by the checksum calculation module 115 in, for example, the memory area immediately after the first memory area 311. In step 2 (202), even if the application program 301 does not explicitly notify the protocol stack 302 of the checksum value, in step 3 (203), the protocol stack 302 has a memory area immediately after the first memory area 311. It is also possible to use a value obtained by reading as a checksum value.

  The protocol stack 302 can be implemented by simply modifying a protocol stack having an existing API specification. That is, in the API function of the protocol stack having the well-known representative socket API specification shown in FIGS. 10 and 11, the write function 1006 or the sendto function 1106 is not given only the socket and data (memory area). The checksum value of the data is also given, and the data may be modified to execute Step 3 (203) to Step 5 (205).

  In step 1 (201), the corresponding application program 301 divides the stream data for each size to be used for communication and calculates each checksum value using the checksum calculation module 115 (as described above, the stream interface 114). In step 2 (202), the checksum value obtained together with the memory area may be specified and the functions may be called.

  Then, a flag is shared in advance between the application program 301 and the protocol stack 302, and the application program 301 initializes the flag before calling these functions. If the value of the flag is changed, the application program 301 observes the value of the flag, so that the protocol stack 302 can notify the application program 301 that transmission has been completed.

  In step 5 (205), another method for notifying that the protocol stack 302 has completed transmission to the application program 301 is to add a new API function to the protocol stack 302 for registering a function to call back to the application program 301. A callback function (event listener) is prepared in advance in the application program 301, the application program 301 registers the callback function in advance using the API function, and the protocol stack 302 in step 5 (205) Call that function.

  In step 5 (205), another method for notifying that the protocol stack 302 has completed transmission to the application program 301 is as follows. The application program 301 prepares an interrupt processing function in advance, and the protocol stack 302 performs step 5 (step 5 (205)). 205), an interrupt request corresponding to the interrupt processing function may be generated.

  According to the stream data communication method and the stream data communication apparatus described above, the stream data can be transmitted without causing a data copy accompanied by a checksum calculation between the application program and the protocol stack. And efficient consumption of the processing load of the processor.

  The stream interface 114 of this embodiment can include a time stamp insertion module (not shown). The time stamp insertion module inserts (relative) time data (time stamp) for each predetermined size into the stream data input from the streamer 132 to the stream interface 114.

  In this case, in the previous description, all “stream data” except the stream data input from the streamer 132 to the stream interface 114 can be read as “stream data with a time stamp inserted”. By doing so, the communication partner (reception side) refers to this time stamp value, so that the communication partner can handle the stream data at the same time relative to the input from the streamer 132.

  Further, the stream interface 114 of the present embodiment can include an encryption / decryption module (not shown). The encryption / decryption module decrypts the encrypted stream data input from the streamer 132 to the stream interface 114 and returns the stream data to the original stream data.

  In this case, in the previous description, it is possible to replace only “stream data” (encrypted) input (encrypted) from the streamer 132 with the stream interface 114 as “encrypted stream data”. By doing so, the stream data flowing through the external bus 131 is encrypted, and it is possible to avoid illegal duplication of the stream data due to the attack of the external bus 131.

  The encryption / decryption module encrypts stream data input from the streamer 132 to the stream interface 114. In this case, in the previous description, it can be implemented by replacing all “stream data” except stream data input from the streamer 132 to the stream interface 114 as “encrypted stream data”. By doing this, the stream data flowing through the network 122 up to the communication partner (reception side) is encrypted, and it becomes possible to avoid illegal duplication of stream data and the like due to the attack of the network 122. .

(Embodiment 2)
<Configuration of stream data communication apparatus>
The configuration of the stream data communication apparatus according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 4 is a block diagram showing the configuration of the stream data communication apparatus according to Embodiment 2 of the present invention, which is a configuration for receiving stream data.

  In FIG. 4, the outline of the operation of the parts having the same reference numerals as those in FIG. 1 described in the first embodiment is the same as that in the first embodiment, and thus description thereof is omitted here.

  The stream data communication apparatus 401 includes a processor 111, a memory 112, a communication interface 413 that transmits and receives data, and a stream interface 414 that inputs and outputs stream data. The processor 111, the memory 112, the communication interface 413, and the stream interface 414 are connected via an internal bus 116.

  Each of the processor 111, the communication interface 413, and the stream interface 414 leads the internal bus 116 (is a bus master) particularly for access to the memory 112. The communication interface 413 includes a checksum calculation module 415 that performs checksum calculation.

<Stream Data Communication Method of Stream Data Communication Device>
Next, the stream data communication method of the stream data communication apparatus according to Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 5 is a flowchart showing the stream data communication method of the stream data communication apparatus according to Embodiment 2 of the present invention, and shows the operation when receiving stream data. FIG. 6 is a diagram showing a data arrangement in the memory when stream data is received in the stream data communication method of the stream data communication apparatus according to Embodiment 2 of the present invention.

  First, the processor 111 operates according to three types of programs stored in the memory 112, that is, an application program 601, a protocol stack 602, and an OS (kernel) (not shown).

  In the following, the operation of the stream data communication apparatus 401 when receiving stream data using a program (application program 601 or protocol stack 602) being processed by the processor 111 instead of the word “processor 111” will be described.

  First, in step 1 (501), the protocol stack 602 calculates a checksum value of received data from a communication partner (not shown) to the communication interface 413 and stores the received data in the first memory area 611. Instruct to store. Thereby, the communication interface 413 stores the received data in the first memory area 611 while calculating the checksum value of the received data from the communication partner using the checksum calculation module 415.

  In step 1 (501), the checksum calculation module 415 ignores the first predetermined size data in which the protocol header always exists in the received data, and calculates the checksum value of the remaining part. It can be implemented. The checksum calculation module 415 can also be implemented so as to ignore data of an appropriate size by interpreting whether the protocol header is not expanded from the received data. Furthermore, the checksum calculation module 415 ignores some of the components (port number, etc.) of the protocol header referred to the calculation of the checksum value stored in the TCP header or UDP header. It is also possible to calculate the checksum value together with the part.

  Next, in step 2 (502), the protocol stack 602 interprets the data (protocol header) 612 to be used for communication among the data stored in the first memory area 611, and stores the remaining data. In step 1 (501), the checksum value calculated by the checksum calculation module 415 is also used to determine whether the application program 601 should handle appropriate data while extracting (recognizing) the second memory area 613. To do.

  That is, the address included in the protocol header 612 and the network address of the stream data communication apparatus 401 match, or the port number included in the protocol header 612 matches the port number of the application program 601, or the protocol header 612 Check calculated from the checksum value stored in the TCP header or UDP header included in the header, part of the components of the protocol header 612 (port number, etc.) and the data stored in the second memory area 613 Whether the thumb values are consistent, etc. In the determination of the consistency of the checksum value, the checksum value obtained in step 1 (501) is used without reading the data stored in the second memory area 613.

  If it is determined by this determination that the data is not to be handled by the stream data communication device 401 (data to another communication device or data estimated to be damaged, etc.), the protocol stack 602 first memory The data stored in the area 611 is discarded (ignored). When the protocol stack 602 recognizes that the data should be handled, the protocol stack 602 performs corresponding processing. If the protocol stack 602 recognizes that the data should be handled by another application program that is not the application program 601, the protocol stack 602 performs the following steps for the corresponding application program.

  Although not shown, only when it is recognized that the data should be handled by the application program 601, the process proceeds to the next step 3 (503). In other cases, the process returns to step 1 (501).

  Furthermore, in step 3 (503), the application program 601 instructs the protocol stack 602 to receive.

  Here, step 1 (501), step 2 (502), and step 3 (503) do not change the order of step 1 (501) and step 2 (502), but the reception instruction timing of application program 601 and the communication partner. Depending on the arrival timing of received data from, the order may be changed regardless of the order shown in FIG.

  That is, Step 3 (503) is followed by Step 3 (503), followed by Step 2 (502), or Step 3 (503) is followed by Step 1 (501), followed by Step 2. (502) may follow.

  Next, in step 4 (504), the protocol stack 602 notifies the application program 601 of the second memory area 613 in which stream data to be handled by the application program 601 is stored.

  Next, in step 5 (505), the application program 601 instructs the stream interface 414 to output the stream data stored in the informed second memory area 613 to the streamer 132.

  Thereby, the stream interface 414 outputs the stream data stored in the second memory area 613 to the streamer 132.

  Next, when recognizing the completion of output, the application program 601 notifies the protocol stack 602 that use has been completed in step 6 (506).

  Finally, after the protocol stack 602 knows that the use is completed in step 6 (506), the protocol stack 602 releases the second memory area 613 (using the memory management function of the OS) or uses it for another purpose. Another data can be re-stored, or the next received data can be re-stored in the first memory area 611 by restarting from step 1 (501). Conversely, before the use completion is known, the protocol stack 602 is restricted from releasing or re-storing the second memory area 613.

  In the above, the basic flow in which the application program 601 uses a single stream data included in a single received data has been described, but the stream data communication method is not limited to this. For example, in step 1 (501), the protocol stack 602 instructs to store each received data in each of a plurality of memory areas while calculating each checksum value of a plurality of received data that are sequentially received. In (502), the protocol stack 602 interprets, extracts, and determines the data stored in the respective memory areas. In step 3 (503), the application program 601 instructs to receive a plurality of times, and in step 4 (504), the protocol. The stack 602 notifies the plurality of memory areas, and in step 5 (505), the application program 601 instructs to output each of the stream data stored in the plurality of memory areas, and in step 6 (506), the application Program 601 informs from those completed use, implementations are possible and the like.

  The protocol stack 602 can be implemented by simply modifying a protocol stack having an existing API specification. That is, in step 1 (501), the protocol stack 602 calculates the checksum value of the received data using the checksum calculation module 415 (and so instructs the communication interface 413), and the protocol stack 602 in step 2 (502). Reads the data stored in the second memory area 613 and calculates the checksum value calculated from some of the components of the header 612 (port number and the like) and the data stored in the second memory area 613. Instead, the checksum value obtained in step 1 (501) may be modified to be used.

  In addition, in the API function of the protocol stack having the well-known representative socket API specifications shown in FIGS. 10 and 11, the read function 1005 or the recvfrom function 1105 gives a memory area in which data to be handled by the application program is stored. Instead, it is only necessary to modify so as to give a memory area in which data to be handled by the application program is stored.

  The corresponding application program 601 may be modified to use data stored in a memory area given by these functions.

  Then, a flag is shared in advance between the application program 601 and the protocol stack 602, and the flag is initialized before the protocol stack 602 exits from the processing corresponding to these functions, and the application program 601 executes step 6 (506). If the value of the flag is changed, the protocol stack 602 observes the value of the flag, so that it is possible to notify the protocol stack 602 that the application program 601 has been used.

  In step 6 (506), another method for notifying that the application program 601 has been used to the protocol stack 602 is to prepare a new API function in the protocol stack 602 in advance, and the application program 601 executes step 6 (506). Call that function.

  In step 6 (506), another method for informing the protocol stack 602 that the application program 601 has completed use of the protocol stack 602 is prepared in advance by the protocol stack 602, and the application program 601 executes step 6 (step 506). In step 506), an interrupt request corresponding to the interrupt processing function may be generated.

  According to the stream data communication method and the stream data communication apparatus described above, the stream data can be received without causing a data copy accompanied by a checksum calculation between the protocol stack and the application program. And efficient consumption of the processing load of the processor.

  Note that the stream interface 414 of this embodiment can include a time stamp deletion module (not shown). The time stamp deletion module refers to stream data into which (relative) time data (time stamp) has been inserted by the communication partner (transmission side), by referring to the time stamp value, and the relative time is equal. Thus, the stream data from which the time stamp has been deleted is output to the streamer 132.

  In this case, in the previous description, it is possible to replace all “stream data” except the stream data output from the stream interface 414 to the streamer 132 as “stream data with a time stamp inserted”. By doing so, it becomes possible to output the stream data to the streamer 132 at the same time as the relative time when the communication partner (transmission side) inserts this time stamp.

  Further, the stream interface 414 of this embodiment can include an encryption / decryption module (not shown). The encryption / decryption module encrypts data output from the stream interface 114 to the streamer 132. In this case, in the previous description, this can be implemented by replacing only “stream data” output from the stream interface 414 to the streamer 132 with “encrypted stream data”. By doing so, the stream data flowing through the external bus 131 is encrypted, and it is possible to avoid illegal duplication of the stream data due to the attack of the external bus 131.

  The encryption / decryption module decrypts the stream data encrypted by the communication partner (transmission side) and returns the stream data to the original stream data. In this case, in the previous description, it is possible to read all “stream data” except the stream data output from the stream interface 414 to the streamer 132 as “encrypted stream data”. By doing so, stream data flowing through the network 122 from the communication partner (reception side) is encrypted, and it becomes possible to avoid illegal duplication of stream data and the like due to the attack of the network 122. .

(Embodiment 3)
<Configuration of stream data communication apparatus>
The configuration of the stream data communication apparatus according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 7 is a block diagram showing the configuration of the stream data communication apparatus according to Embodiment 3 of the present invention, which is a configuration for transmitting and receiving stream data.

  In FIG. 7, the outline of the operation of the parts having the same reference numerals as those in FIGS. 1 and 4 described in the first and second embodiments is the same as that in the first and second embodiments, and thus description thereof is omitted here.

  The stream data communication device 701 includes a processor 111, a memory 112, a communication interface 113 that transmits and receives data, a stream interface 414 that inputs and outputs stream data, and a checksum calculation module 715 that performs checksum calculation. Is provided.

  The processor 111, the memory 112, the communication interface 113, the stream interface 414, and the checksum calculation module 715 are connected via the internal bus 116. The processor 111, the communication interface 113, the stream interface 414, and the checksum calculation module 715 respectively lead the internal bus 116 for access to the memory 112 (is a bus master).

<Stream Data Communication Method of Stream Data Communication Device>
Next, the stream data communication method of the stream data communication apparatus according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 8 is a flowchart showing the stream data communication method of the stream data communication apparatus according to Embodiment 3 of the present invention, and shows the operation when transmitting stream data. The data arrangement in the memory when receiving the stream data of the present embodiment is the same as that shown in FIG. 3 described in the first embodiment, and will be described using that.

  Hereinafter, the operation of the stream data communication apparatus 701 in the case of transmitting stream data using a program (application program 301 or protocol stack 302) being processed by the processor 111 as a word instead of the word processor 111 will be described.

  First, in step 1 (801), the application program 301 instructs the stream interface 414 to store the stream data input from the streamer 132 in the first memory area 311. Thereby, the stream interface 414 stores the stream data in the first memory area 311 while calculating the checksum value of the input stream data using the checksum calculation module 115.

  Next, in step 2 (802), the application program 301 instructs the protocol stack 302 to specify the first memory area 311 for transmission.

  Next, in step 3 (803), the protocol stack 302 instructs the checksum calculation module 715 to calculate the checksum value of the data stored in the designated first memory area 311. . As a result, the checksum calculation module 715 reads the data stored in the first memory area 311 from the memory 112 and calculates the checksum value.

  Next, in step 4 (804), using the obtained checksum value, data (protocol header) for generating the stream data stored in the designated first memory area 311 for communication is generated. Then, it is stored in the second memory area 312. In step 4 (804), the data stored in the first memory area 311 is not read, and the checksum value obtained in step 3 (803) is used to check the value and some of the components of the protocol header. And the checksum value to be stored in the TCP header or UDP header.

  The remaining Step 5 (805) and Step 6 (806) are the same as Step 4 (204) and Step 5 (205) in Embodiment 1 shown in FIG.

  In the above description, the basic flow in which the application program 301 transmits single stream data as single transmission data has been described, but the stream data communication method is not limited to this.

  For example, in step 1 (801), the application program 301 instructs each stream data to be sequentially input to be stored in each of a plurality of memory areas. In step 2 (802), the application program 301 stores each memory area. In step 3 (803), the protocol stack 302 instructs to calculate the checksum value of the data stored in each designated memory area, and in step 4 ( In 804), the protocol stack 302 can also generate corresponding protocol headers, respectively.

  The protocol stack 302 can be implemented by simply modifying a protocol stack having an existing API specification. That is, in the API function of the protocol stack having the well-known representative socket API specification shown in FIGS. 10 and 11, when the write function 1006 or the sendto function 1106 is called, the steps 3 (803) to 6 (806) are called. ) To execute.

  The method for notifying that the protocol stack 302 has completed transmission to the application program 301 in step 6 (806) is the same as that in step 5 (205) in the first embodiment, and thus the description thereof is omitted here.

  According to the stream data communication method and the stream data communication apparatus described above, stream data can be generated without causing data copy (reading from the memory and writing to the memory) that involves checksum calculation between the application program and the protocol stack. It can be sent. Although only reading of data accompanied by checksum calculation from the memory occurs for all stream data, the checksum calculation is not mainly performed by the processor but by the checksum calculation module. Therefore, although considered to be inferior to the first embodiment, it is possible to achieve efficient use of bus bandwidth and efficient use of processor processing load.

  Note that the stream interface 414 of this embodiment can include a time stamp insertion module (not shown) or an encryption / decryption module (not shown), and its function can be used to obtain the effect. The possibility is the same as that of the stream interface 114 in the first embodiment, and thus the description is omitted here.

(Embodiment 4)
<Configuration of stream data communication apparatus>
The configuration of the stream data communication apparatus according to the third embodiment is the same as that shown in FIG. Since the outline of the operation is the same as that of the third embodiment, the description is omitted here.

<Stream Data Communication Method of Stream Data Communication Device>
Next, a stream data communication method of the stream data communication apparatus according to Embodiment 4 of the present invention will be described with reference to FIG. FIG. 9 is a flowchart showing the stream data communication method of the stream data communication apparatus according to Embodiment 3 of the present invention, and shows the operation when receiving stream data. Note that the data arrangement in the memory when receiving the stream data of the present embodiment is the same as that shown in FIG. 6 in the second embodiment, and will be described below.

  In the following, the operation of the stream data communication apparatus 701 in the case where stream data is received using a program (application program 601 or protocol stack 602) being processed by the processor 111 as a word instead of the word processor 111 will be described.

  First, in step 1 (901), the protocol stack 602 instructs the communication interface 113 to store received data from a communication partner (not shown) in the first memory area 611. As a result, the communication interface 113 stores the received data from the communication partner in the first memory area 611.

  Next, in step 2 (902), the protocol stack 602 interprets the data (protocol header) 612 to be used for communication among the data stored in the first memory area 611, and stores the remaining data. The extracted second memory area 613 is extracted (recognized) while determining whether the data is appropriate data to be handled by the application program 601.

  That is, whether the address included in the protocol header 612 matches the network address of the stream data communication apparatus 701, or whether the port number included in the protocol header 612 matches the port number of the application program 601. In step 2 (902), the checksum value consistency is not determined.

  If it is determined by this determination that the data to be handled by the stream data communication device 701 is not data to be handled (data to another communication device or data estimated to be damaged), the protocol stack 602 first memory The data stored in the area 611 is discarded (ignored). When the protocol stack 602 recognizes that the data should be handled, the protocol stack 602 performs corresponding processing.

  If the protocol stack 602 recognizes that the data should be handled by another application program that is not the application program 601, the protocol stack 602 performs the following steps for the corresponding application program. Although not shown, only when it is recognized that the data should be handled by the application program 601, the process proceeds to the next step 3 (903), and in other cases, the process returns to step 1 (901).

  Next, in step 3 (903), the protocol stack 602 instructs the checksum calculation module 715 to calculate the checksum value of the data stored in the extracted second memory area 613. . As a result, the checksum calculation module 715 reads the data stored in the second memory area 613 from the memory 112 and calculates the checksum value.

  Next, in step 4 (904), the protocol stack 602 checks the checksum value stored in the TCP header or UDP header included in the protocol header 612 and some of the components (port number, etc.) of the protocol header 612. And the checksum value calculated from the data stored in the second memory area 613 are determined to match. In step 4 (904), the checksum value calculated by the checksum calculation module 715 obtained in step 3 (903) is used without reading the data stored in the second memory area 613.

  In step 5 (905), the application program 601 instructs the protocol stack 602 to receive.

  Here, step 1 (901) to step 4 (904) and step 5 (905) do not change the order of step 1 (901) to step 4 (904), but the reception instruction timing of the application program 601 and the communication partner. Depending on the arrival timing of received data from, the order may be changed regardless of the order shown in FIG.

  The remaining Step 6 (906) to Step 8 (908) are the same as Step 4 (504) to Step 6 (506) in the second embodiment, respectively, and thus description thereof is omitted here.

  In the above, the basic flow in which the application program 601 uses a single stream data included in a single received data has been described, but the stream data communication method is not limited to this.

  For example, in step 1 (901), the protocol stack 602 instructs to store a plurality of received data sequentially received in each of a plurality of memory areas, and in step 2 (902), the protocol stack 602 stores each of the memory areas. In step 3 (903), the protocol stack 602 instructs to calculate the checksum value of the data stored in each specified memory area. In step 4 (904), the protocol stack 602 determines the validity of the data stored in each memory area. In step 5 (905), the application program 601 instructs to receive a plurality of times. Implementation is also possible.

  The protocol stack 602 can be implemented by simply modifying a protocol stack having an existing API specification. That is, the protocol stack 602 calculates the checksum value in the step 3 (903) using the checksum calculation module 715 (instructing the checksum calculation module 715 to do so), and the protocol header in the step 4 (904). Reading the data stored in the second memory area 613 and calculating the checksum value calculated from the data stored in the second memory area 613 and part of the components 612 (port number, etc.) Instead, the checksum value obtained in step 3 (903) may be modified to be used.

  In addition, in the API function of the protocol stack having the well-known representative socket API specifications shown in FIGS. 10 and 11, the read function 1005 or the recvfrom function 1105 gives a memory area in which data to be handled by the application program is stored. Instead, it is only necessary to modify so as to give a memory area in which data to be handled by the application program is stored. The corresponding application program 601 may be modified to use data stored in a memory area given by these functions.

  In step 8 (908), the method for notifying the protocol stack 602 that the application program 601 has completed use is the same as in step 6 (506) in the second embodiment, and thus description thereof is omitted here.

  According to the stream data communication method and the stream data communication apparatus described above, stream data can be generated without causing data copy (reading from the memory and writing to the memory) that involves checksum calculation between the application program and the protocol stack. It can be received. Although only reading of data accompanied by checksum calculation from the memory occurs for all stream data, the checksum calculation is not mainly performed by the processor but by the checksum calculation module.

  Therefore, although considered to be inferior to the second embodiment, it is possible to achieve efficient use of the bus bandwidth and efficient use of the processing load of the processor.

  Note that the stream interface 414 of this embodiment can include a time stamp deletion module (not shown) or an encryption / decryption module (not shown), and the effect can be obtained by using the function. Since implementation is the same as in the second embodiment, description thereof is omitted here.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  For example, the constituent elements of the stream data communication apparatuses 101, 401, and 701 shown in FIGS. 1, 4, and 7, the processor 111, the memory 112, the communication interfaces 113 and 413, the stream interfaces 114 and 414, the checksum calculation module 115, Each of 415 and 715 can be implemented by separate semiconductor chips, or a plurality or all of them can be implemented by one semiconductor chip.

  That is, each of the stream data communication devices 101, 401, and 701 can be implemented as a set of a plurality of semiconductor chips combined, or can be implemented as a single semiconductor chip.

  Each of the communication interfaces 113 and 413 uses a communication cable 121, so that it corresponds to a wired network. However, the communication interfaces 113 and 413 can also be implemented to support a wireless network that does not use a communication cable. is there.

  The present invention relates to a stream data communication method and a stream data communication apparatus, and is particularly applicable to prevention of waste of bus bandwidth and prevention of processor processing load using a protocol stack similar to a checksum calculation module and a socket.

  101, 401, 701 ... stream data communication device, 111 ... processor, 112 ... memory, 113, 413 ... communication interface, 114, 414 ... stream interface, 115, 415, 715 ... checksum calculation module.

Claims (4)

A stream data communication method for a stream data communication apparatus that operates from a program composed of an application program and a protocol stack and outputs stream data included in received data received from a communication interface having a checksum calculation module from the stream interface Because
Directing the protocol stack to store the received data in a first memory area while calculating a checksum value of the received data to the communication interface;
The protocol stack interpreting a protocol header of data stored in the first memory area, and extracting the second memory area and determining the validity of the received data using the checksum value; ,
The application program instructing the protocol stack to receive;
The protocol stack notifying the application program of the second memory area;
Instructing the application program to output stream data stored in the second memory area to the stream interface;
A stream data communication method comprising: a step of notifying the protocol stack that use of the application program is completed. Stream data communication of a stream data communication device that operates by a program composed of an application program and a protocol stack and outputs stream data included in received data received from the communication interface from the stream interface using a checksum calculation module A method,
The protocol stack directing the communication interface to store the received data in a first memory area;
The protocol stack interprets a protocol header of data stored in the first memory area and extracts a second memory area to determine validity of the received data;
Instructing the checksum calculation module to calculate a checksum value of data stored in the second memory area;
The protocol stack determining the validity of the received data using the component of the protocol header and the checksum;
The application program instructing the protocol stack to receive;
The protocol stack notifying the application program of the second memory area;
Instructing the application program to output stream data stored in the second memory area to the stream interface;
A stream data communication method comprising: a step of notifying the protocol stack that use of the application program is completed. A stream interface to which stream data is input;
A communication interface having a checksum calculation module and transmitting the stream data;
A memory for storing a program composed of an application program and a protocol stack;
A processor for processing the program,
The processor is
The protocol stack instructs the communication interface to store the received data in the first memory area of the memory while calculating a checksum value of the received data.
The protocol stack interprets the protocol header of the data stored in the first memory area, extracts the second memory area of the memory, and uses the checksum value to validate the received data. Judgment,
The application program instructs the protocol stack to receive,
Informing the application program of the second memory area by the protocol stack;
Instructing the stream interface to output the stream data stored in the second memory area by the application program;
A stream data communication apparatus characterized in that the application program notifies the protocol stack that use has been completed. A stream interface to which stream data is input;
A communication interface for transmitting the stream data;
A checksum calculation module;
A memory for storing a program composed of an application program and a protocol stack;
A processor for processing the program,
The processor is
Instructing the communication interface to store received data in the first memory area of the memory by the protocol stack;
The protocol stack interprets the protocol header of the data stored in the first memory area, determines the validity of the received data while extracting the second memory area of the memory,
Instructing the checksum calculation module to calculate a checksum value of data stored in the second memory area by the protocol stack;
The protocol stack determines the validity of the received data using the component of the protocol header and the checksum,
The application program instructs the protocol stack to receive,
The protocol stack informs the application program of the second memory area,
Instructing the stream interface to output the stream data stored in the second memory area by the application program;
A stream data communication apparatus characterized in that the application program notifies the protocol stack that use has been completed.

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