JP6800514B2 - Communication equipment, its control method, and programs - Google Patents

Description

The present invention relates to a communication device for performing data communication, a control method thereof, and a program.

In data communication, there is a communication method provided with a mechanism for detecting a data error. For example, TCP / IP (Transmission Control Protocol / Internet Protocol), which is the main protocol used in Internet communication, is a checksum obtained by adding a complement of 1 in order to detect an error in the data of a TCP packet. Is used. However, if the checksum calculation is performed by processing by software calculation, there is a problem that the processing load increases and the communication processing performance deteriorates.

As a method for solving this problem, a method of performing checksum calculation while copying data using DMA (Direct Memory Access) has been proposed (see Patent Document 1). According to this method, it is possible to reduce the processing load of the apparatus and prevent deterioration of communication processing performance.

Japanese Unexamined Patent Publication No. 2015-207222

In the method described in Patent Document 1, a checksum operation is performed in units of data transferred between memories using DMA. When this method is used at the time of DMA transfer from the storage unit in the wireless module to the storage unit in the network stack in the reception processing of TCP / IP communication, the data string before being analyzed by the network stack is the checksum calculation target. Therefore, in order to calculate the checksum of the TCP packet, a correction process for deleting the checksum of an unnecessary part such as the IP header is required. However, since the correction processing time increases in proportion to the header size of the packet, there is a problem that the communication performance deteriorates.

The present invention has been made in view of the above problems, and an object of the present invention is to reduce the load of checksum calculation processing at the time of reception.

As one means for achieving the above object, the communication device of the present invention has the following configuration. That is, matching of the received packet with respect to the first checksum calculation means for calculating the checksum for the received packet received from another communication device and the checksum calculated by the first checksum calculation means. A correction means for performing correction necessary for confirming the property, a second checksum calculation means for calculating a checksum for a packet to which a predetermined protocol process has been applied to the received packet, and a predetermined condition. Based on the determination means for determining whether to perform the correction by the correction means or the checksum calculation by the second checksum calculation means, and the correction means based on the result of the determination by the determination means. It has a checksum for confirming the consistency of the received packet by using the corrected checksum or the checksum calculated by the second checksum calculation means.

According to the present invention, it is possible to improve the communication performance by reducing the load of the checksum calculation process at the time of reception.

The block diagram which shows the hardware configuration example of a communication device 10. The block diagram which shows the functional configuration example of a communication device 10. The schematic diagram explaining the calculation procedure of the checksum calculated and corrected by the 1st checksum calculation unit 111 and the checksum correction unit 208. The schematic diagram explaining the checksum calculation procedure calculated by the 2nd checksum calculation unit 207. FIG. 5 is a flowchart showing a packet reception processing procedure in which the communication device 10 switches the checksum calculation result to be used based on the performance of the RAN 101. FIG. 5 is a flowchart showing a packet reception processing procedure in which the communication device 10 switches the checksum calculation result to be used based on the performance of the CPU 103.

Hereinafter, the present invention will be described in detail based on the embodiments with reference to the accompanying drawings. The configuration shown in the following embodiments is only an example, and the present invention is not limited to the illustrated configuration.

(First Embodiment)
As a first embodiment, a checksum calculation result used for confirming the integrity of a received packet is obtained based on the performance of the memory of the communication device and / or the protocol type used and / or the configuration of the received packet. A communication device that can be switched will be described.

[Device configuration]
The hardware configuration and functional configuration of the communication device 10 in the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing a hardware configuration example of the communication device 10, and FIG. 2 is a block diagram showing a functional configuration example of the communication device 10. Specific examples of the communication device 10 include a digital camera, a digital video camera, a mobile phone, a smartphone, a PC (Personal Computer), a notebook PC, a server, and the like.

First, the hardware configuration of the communication device 10 will be described. As shown in FIG. 1, the communication device 10 has a data transfer unit 110 including a RAM 101, a ROM 102, a CPU 103, a display unit 104, an operation unit 105, a timer management unit 106, and a first checksum calculation unit 111. The communication device 10 also has a media access control module (MAC) 107 and a physical layer module (PHY) 108. The RAM represents Random Access Memory, the ROM represents Read Only Memory, and the CPU represents the Central Processing Unit. It is not essential that the communication device 10 has all of these hardware components.

The RAM 101 temporarily stores programs and data. Although one RAM 101 is shown in FIG. 1, the communication device 10 may have a plurality of RAM 101s having different performances. The ROM 102 stores programs and parameters that can be executed by the CPU 103. The CPU 103 is a processor that controls the operation of the entire communication device 10. For example, the CPU 103 uses the RAM 101 as a work memory to execute various programs stored in a storage medium such as a ROM 102 or an HDD (Hard Disc Drive) (not shown). The program executed by the CPU 103 includes a network driver. When the CPU 103 executes the network driver, a function of protocol processing including packet reception processing described later is realized.

The display unit 104 performs various displays. For example, the display unit 104 displays a GUI (Graphic User Interface) for the user to operate the communication device 10. The operation unit 105 is an input interface for the user to operate the communication device 10. The timer management unit 106 manages the passage of time such as program processing. The MAC 107 and PHY 108 are communication units that communicate via a network such as a wireless LAN (Local Area Network) by Wi-Fi via an antenna 109. When the CPU 103 executes the network driver, the MAC 107 is controlled, and data (packets) are transmitted and received via the PHY 108 and the antenna 109. In this embodiment, the wireless LAN communication function by Wi-Fi is used, but the present invention is not limited to this, and if IP (Internet Protocol) communication is possible, other communication such as Ethernet (registered trademark) of the wired LAN communication function is used. The method may be used.

The data transfer unit 110 is configured as a DMAC (Direct Memory Access Controller) and transfers data between memories. The first checksum calculation unit 111 in the data transfer unit 110 calculates the checksum of the data to be transferred at the time of data transfer. The first checksum calculation unit 111 can perform a checksum calculation without increasing the number of steps for the processing steps in the data transfer unit 110.

Subsequently, the functional configuration of the communication device 10 will be described. As shown in FIG. 2, the communication device 10 includes a function control unit 201, a wireless LAN control unit 202, a display control unit 203, an operation control unit 204, and a storage control unit 205. The communication device 10 also has a TCP / IP control unit 206, a second checksum calculation unit 207, and a checksum correction unit 208. The processing of each of these functional components can be realized by the CPU 103 expanding the program stored in the ROM 102 into the RAM 101 and executing the program. On the other hand, in order to realize the processing of each of these functional components by hardware, the arithmetic unit and the circuit corresponding to the processing of these functional components may be configured by hardware. It is not essential that the communication device 10 has all of these functional components.

The function control unit 201 controls each functional component (wireless LAN control unit 202 to checksum correction unit 208). The wireless LAN control unit 202 controls MAC 107 and PHY 108, and controls for wireless LAN communication with other communication devices. When the communication device 10 connects to another communication device via an external wireless access point, the wireless LAN control unit 202 controls MAC 107 and PHY 108 to perform wireless LAN communication with the wireless access point (not shown). Do.

The display control unit 203 controls the display unit 104 to display various types of information. The operation control unit 204 receives an operation input from the user to the communication device 10 via the operation unit 105, and performs control according to the input. The storage control unit 205 controls the RAM 101, and stores data such as processed data, image contents, and video contents in the RAM 101 or deletes the data from the RAM 101.

The TCP / IP control unit 206 performs TCP (Transmission Control Protocol) / IP (Internet Protocol) communication control with other communication devices. Further, the TCP / IP control unit 206 analyzes the received packet stored in the RAM 101 and divides it into a wireless header, an Ethernet (registered trademark) header (ETH header), an IP header, a TCP header, a TCP payload, and the like. Perform protocol processing. In this embodiment, an example of using TCP / IP communication is shown, but the present invention is not limited to this, and other protocols that use checksums may be used. The second checksum calculation unit 207 performs a checksum calculation on a packet that has undergone a predetermined protocol process in the TCP / IP control unit 206. The second checksum calculation unit 207 can be used by the TCP / IP control unit 206. The checksum correction unit 208 corrects the checksum value calculated by the first checksum calculation unit 111. The checksum correction unit 208 can be used by the TCP / IP control unit 206. The TCP / IP control unit 206 confirms the consistency of the received packet by using the checksum generated by the second checksum calculation unit 207 or the checksum correction unit 208.

[Checksum operation]
Next, the checksum calculation method in TCP in the present embodiment will be described with reference to FIGS. 3 and 4.

FIG. 3 is a schematic diagram illustrating a checksum calculation procedure calculated and corrected by the first checksum calculation unit 111 and the checksum correction unit 208. For the sake of the explanation of FIG. 3, it is assumed that the communication device 10 communicates with another communication device via Ethernet (registered trademark) as a transmission path via an external wireless access point. This description is also applicable.

When the wireless LAN control unit 202 receives the packet transmitted from another communication device (not shown) via the antenna 109, PHY 108, and MAC 107, the data transfer unit 110 receives the RAM 101 from the storage unit (not shown) in the MAC 107. Forward the received packet to. At the time of this transfer, the first checksum calculation unit 111 calculates the checksum (CS302) of the entire received packet. The data transfer unit 110 associates the CS 302 with the received packet 301 and transfers the CS 302 to the RAM 101.

The TCP / IP control unit 206 analyzes the received packet 301 stored in the RAM 101 by performing protocol processing. As a result, the analyzed received packet 303 divided into the radio header, the Ethernet (registered trademark) header (ETH header), the IP header, the TCP header, and the TCP payload is generated.

Next, the TCP / IP control unit 206 uses the checksum correction unit 208 to subtract the checksum of the header unit unnecessary for the TCP checksum from the CS302 and add the checksum of the TCP virtual header. , TCP checksum 305 is calculated. Here, the header part that does not require the checksum of TCP is a wireless header, an Ethernet (registered trademark) header, and an IP header in the present embodiment. The unnecessary header unit to be subtracted may change depending on the data range of the received packet transferred from the data transfer unit 110. Further, the TCP virtual header is a well-known header necessary for calculating a TCP checksum, and is composed of a source IP address, a destination IP address, and the like. The TCP / IP control unit 206 confirms the consistency of the received packet (performs an error detection process) using the calculated TCP checksum 305.

As a result of checking the consistency, when the TCP / IP control unit 206 confirms that there is no error in the received packet, the TCP / IP control unit 206 passes the data of the received packet to the application 306. On the other hand, when the TCP / IP control unit 206 confirms that the received packet has an error, the TCP / IP control unit 206 discards the received packet.

FIG. 4 is a schematic diagram illustrating a checksum calculation procedure calculated by the second checksum calculation unit 207. For the explanation of FIG. 4, it is assumed that the communication device 10 communicates with another communication device via an external wireless access point via Ethernet (registered trademark) as a transmission path, as in FIG. , This description is also applicable to other communication modes.

When the wireless LAN control unit 202 receives the packet transmitted from another communication device (not shown) via the antenna 109, PHY 108, and MAC 107, the data transfer unit 110 receives the RAM 101 from the storage unit (not shown) in the MAC 107. Forward the received packet to. The TCP / IP control unit 206 analyzes the received packet stored in the RAM 101 and divides it into a wireless header, an Ethernet (registered trademark) header (ETH header), an IP header, a TCP header, and a TCP header. To generate.

The TCP / IP control unit 206 uses the second checksum calculation unit 207 to calculate the checksum of the TCP header, the TCP payload, and the TCP virtual header in the analyzed received packet 303 as the checksum of TCP. Subsequently, the TCP / IP control unit 206 confirms the consistency of the received packet by using the calculated TCP checksum.

When the TCP / IP control unit 206 confirms that the received packet is correct from the TCP checksum, it passes the received data to the application 306, and when it confirms that the received packet is correct from the TCP checksum, the TCP / IP control unit 206 passes the received data to the application 306. Discard the received packet.

Next, the operation of the communication device 10 will be described with reference to FIG. FIG. 5 is a flowchart showing a packet receiving procedure for switching the use of the calculation results of the two types of checksums described with reference to FIGS. 3 and 4 based on the performance of the RAM 101. In the description of FIG. 5, the same processing as that shown in FIG. 3 or 4 shall use the reference numerals in FIGS. 3 or 4.

In S501, when the wireless LAN control unit 202 receives the packet via the antenna 109, PHY108, and MAC107, the data transfer unit 110 transfers the received packet from the storage unit (not shown) in the MAC 107 to the RAM 101. When the data transfer unit 110 transfers the received packet 301, the first checksum calculation unit 111 calculates the checksum (CS302) of the entire received packet 301. The data transfer unit 110 associates the CS 302 with the received packet 301 and transfers the CS 302 to the T and RAM 101.

In S502, the TCP / IP control unit 206 analyzes the received packet 301 stored in the RAM 101 and divides the received packet 301 into a wireless header, an Ethernet (registered trademark) header (ETH header), an IP header, a TCP header, and a TCP header. Create the received packet 303.

In S503, the TCP / IP control unit 206 acquires the performance of the RAM 101. The performance of RAM refers to, for example, the processing capacity (and the value representing the processing capacity) such as the speed (processing speed) of the operating clock. When the performance of the RAM 101 is high, the difference in communication performance when the calculation results of the first checksum calculation unit 111 and the second checksum calculation unit 207 are used properly becomes small. Therefore, when the performance of the RAM 101 is less than the predetermined level (S503; YES), the process proceeds to S504, and when the performance of the RAM 101 is equal to or higher than the predetermined level (S503; NO), the process proceeds to S506. At this predetermined level (predetermined threshold value), a value indicating an arbitrary memory performance or the like that can maintain a desired communication performance when communicating using the checksum calculated by the first checksum calculation unit 111 is set. Can be done.

In S504, the TCP / IP control unit 206 determines whether the protocol type of the network layer is IPv4 or IPv6. In IPv4, there is a checksum field in the IP header, and the checksum for the IP header is stored. Therefore, if there is no error in the received packet, the checksum 302 calculated by the first checksum calculation unit 111 during IPv4 communication is not included because the checksum for the IP header is offset. That is, in the case of IPv4, the checksum correction unit 208 does not need to subtract the checksum for the IP header. Therefore, when IPv6 having no checksum field in the IP header is used (S504; IPv6), the process proceeds to S505, and when IPv4 having a checksum field in the IP header is used (S504; IPv6). For IPv4), the process proceeds to S506. In S504, IPv4 and IPv6 were determined, but the present invention is not limited to this.

In S505, the TCP / IP control unit 206 confirms the configuration of the received packet and branches the process. First, the TCP / IP control unit 206 acquires the length of the header unit and the length of the IP payload unit from the analyzed received packet 303. The header portion refers to a header portion in a received packet that needs to be subtracted by the checksum correction unit 208, and in the present embodiment, it is a wireless header, an Ethernet (registered trademark) header, and an IP header. As described above, the header unit may change depending on the data range of the received packet transferred by the data transfer unit 110. When the header length occupies a predetermined ratio in the analyzed received packet 303, for example, when the header length is less than the IP payload length (S505; YES), the process proceeds to S506. If the header length does not occupy a predetermined ratio in the analyzed received packet 303, for example, if the header length is equal to or greater than the IP payload length (S505; NO), the process proceeds to S507.

Further, in S505, the TCP / IP control unit 206 may determine the packet type of the received packet. For example, if the received packet has no payload like an acknowledgment (ACK) packet, or the payload length is less than the threshold (S505; YES), the process proceeds to S506 and the payload length is like a data packet. If is a packet type equal to or greater than the threshold value (S505; NO), the process may proceed to S507. For this threshold value, an arbitrary payload length whose communication performance changes can be set by properly using the calculation results of the first checksum calculation unit 111 and the second checksum calculation unit 207. Although the length of the payload is shown as the packet type, the packet type may be determined based on the packet flag, option information, and the like.

In S506, the TCP / IP control unit 206 uses the checksum correction unit 208 to subtract the checksums of the wireless header, the ETHERNET (registered trademark) header, and the IP header from the checksum 302, and the checksum of the TCP virtual header. Is added to calculate the TCP checksum 305. The checksum calculation method is as described with reference to FIG. As described above, the header unit to be subtracted may change depending on the data range of the received packet transferred by the data transfer unit 110. As described above, when the received packet is an IPv4 packet, the checksum correction unit 208 does not need to subtract the checksum for the IP header. Therefore, in the process of S506, if it is determined to be IPv4 in S504 and then executed, a correction process other than the subtraction of the checksum for the IP header is performed.

In S507, the TCP / IP control unit 206 uses the second checksum calculation unit 207 to recalculate the TCP checksum (TCP header, TCP payload, TCP virtual header checksum). The checksum calculation method is as described with reference to FIG.

In S508, the TCP / IP control unit 206 performs an error detection process by checking the consistency of the received packet using the TCP checksum derived in S506 or S507.

In the flowchart shown in FIG. 5, all the determinations of S503, S504, and S505 are performed, but any one or more of these determinations may be performed. For example, if S503 is omitted, the process proceeds to S504 after S502. If S504 is omitted, the process proceeds to S505 when it is determined to be Yes in S503. If S505 is omitted, the process proceeds to S507 when IPv6 is determined in S504. If S504 and S505 are omitted, and if Yes is determined in S503, the process proceeds to S507. If S503 and S504 are omitted, the process proceeds to S505 after S502. If S503 and S505 are omitted, the process proceeds to S504 after S502, and if it is determined to be IPv6 in S504, the process proceeds to S507.

Further, since the determination of S503 and S504 can be performed regardless of the processing of S501 and S502, the determination of S503 or S504 may be performed before S501. For example, in this case, if IPv6 is determined in S504 and / or No is determined in S505, the process of S507 may be performed without performing the processes of S501 and S502. As a result, the processing efficiency can be further improved.

As described above, the communication device 10 according to the present embodiment is used to confirm the consistency of the received packet based on the conditions such as the performance of the memory and / or the protocol type used and / or the configuration of the received packet. Switch the checksum calculation result to be used. That is, it is switched between using a checksum calculation result that requires a correction process having a high processing load such as S506, and using a checksum calculation result that does not require the correction process. In this way, it is possible to select whether or not to use a means having a light load in the checksum calculation process of the received packet as needed, and as a result, the reception efficiency is improved and the communication performance is improved.

(Second Embodiment)
In the second embodiment, the checksum calculation result used for confirming the consistency of the received packet is switched based on the performance of the CPU 103 of the communication device 10. In the second embodiment, the same figures as those in the first embodiment and the same elements as in the drawings will not be described.

FIG. 6 is a flowchart showing a packet receiving procedure for switching the use of the calculation results of the two types of checksums described with reference to FIGS. 3 and 4 based on the performance of the CPU 103. In the description of FIG. 6, the same processing as that shown in FIG. 3 or 4 uses the reference numerals in FIGS. 3 or 4. Further, since the processes of S601 to S602 and S604 to S608 are the same as the processes of S501 to S502 and S504 to S508 of FIG. 5, the description thereof will be omitted.

In S603, the TCP / IP control unit 206 acquires the performance of the CPU 103. The performance of the CPU refers to, for example, the processing capacity (and the value representing the processing capacity) such as the processing speed. When the performance of the CPU 103 is high, the difference in communication performance when the first checksum calculation unit 111 and the second checksum calculation unit 207 are used properly becomes small. Therefore, if the performance of the CPU 103 is less than the predetermined level (S603; YES), the process proceeds to S604, and if the performance of the CPU 103 is equal to or higher than the predetermined level (S603; NO), the process proceeds to S606. At this predetermined level (predetermined threshold value), a value indicating an arbitrary CPU performance or the like that can maintain a desired communication performance when communicating using the checksum calculated by the first checksum calculation unit 111 is set. Can be done.

In the flowchart shown in FIG. 6, all the determinations of S603, S604, and S605 are performed, but determinations other than the determination of S603 may be performed. For example, when S604 is omitted, if Yes is determined in S603, the process proceeds to S605. If S605 is omitted, the process proceeds to S607 when it is determined in S604 that it is, for example, IPv6 other than IPv4. If S604 and S605 are omitted, and if Yes is determined in S603, the process proceeds to S607.

As described above, the communication device 10 according to the present embodiment switches the checksum calculation result used for confirming the consistency of the received packet based on the conditions such as the performance of the CPU 103. That is, it is switched between using a checksum calculation result that requires a correction process having a high processing load such as S606, and using a checksum calculation result that does not require the correction process. In this way, it is possible to select whether or not to use a means having a light load in the checksum calculation process of the received packet as needed, and as a result, the reception efficiency is improved and the communication performance is improved.

(Other embodiments)
The present invention supplies a program that realizes one or more functions of the above-described embodiment to a system or device via a network or storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by the processing to be performed. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

10 Communication device, 101 RAM, 102 ROM, 103 CPU, 104 display unit, 105 operation unit, 106 timer management unit, 107 MAC, 108 PHY, 109 antenna, 110 data transfer unit, 111 first checksum calculation unit, 201 Function control unit, 202 wireless LAN control unit, 203 display control unit, 204 operation control unit, 205 storage control unit, 206 TCP / IP control unit, 207 second checksum calculation unit, 208 checksum correction unit

Claims (9)

It ’s a communication device,
A first checksum calculation means that calculates a checksum for received packets received from other communication devices,
A correction means for making a correction necessary for confirming the consistency of the received packet with respect to the checksum calculated by the first checksum calculation means.
A second checksum calculation means for calculating a checksum for a packet to which a predetermined protocol process has been applied to the received packet, and
A determination means for determining whether to perform correction by the correction means or a checksum calculation by the second checksum calculation means based on a predetermined condition, and
Based on the result of the determination by the determination means, the checksum corrected by the correction means or the checksum calculated by the second checksum calculation means is used as a confirmation means for confirming the consistency of the received packet. ,
A communication device characterized by having. Wherein the predetermined condition, the communication apparatus according to claim 1, characterized in that it comprises a condition corresponding to the processing capability of the communication device. The determination means corrects by the correction means when the performance of the memory possessed by the communication device is equal to or higher than the first level, and when the performance of the memory is lower than the first level, the second level. The communication device according to claim 2, wherein it is determined that the checksum is calculated by the checksum calculation means. The determination means corrects by the correction means when the performance of the processor of the communication device is equal to or higher than the second level, and when the performance of the processor is less than the second level, the second level is corrected. The communication device according to claim 2 , wherein it is determined that the checksum is calculated by the checksum calculation means. Wherein the predetermined condition, the communication apparatus according to claim 1 or 2, characterized in that it comprises a condition corresponding to the type of protocol for the protocol processing. It is determined that the determination means performs correction by the correction means when the protocol type is IPv4, and performs checksum calculation by the second checksum calculation means when the protocol type is other than IPv4. The communication device according to claim 5, wherein the communication device is characterized by the above. Wherein the predetermined condition, the communication device according to any one of claims 1, 2 or 5, characterized in that it comprises a condition that the protocol processing corresponding to the configuration of the decorated packets. It is a control method for communication devices.
Based on a predetermined condition, the checksum calculated for the received packet received from another communication device is corrected as necessary for confirming the consistency of the received packet, or the received packet is corrected. Based on the determination step of determining whether to calculate the checksum for the packet subjected to the predetermined protocol processing and the determination result in the determination step.
A confirmation step of confirming the consistency of the received packet by using the checksum obtained by the correction or the checksum calculated for the packet subjected to the predetermined protocol processing .
A method for controlling a communication device, which comprises. A program for causing a computer to function as a communication device according to any one of claims 1 to 7 .

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