JP6123476B2 - Communication apparatus and communication system - Google Patents

Description

  The present invention relates to a communication device and a communication system.

In TCP / IP (Transmission Control Protocol / Internet Protocol) communication, which is standardly used on the Internet and intranets, the protocol processing is performed by a CPU (Central Processing Unit) such as a network server or information processing device that handles network data. It has been broken.
Such protocol processing places a heavy load on the CPU. Therefore, a technique for reducing the load on the CPU by converting a protocol process requiring a lot of CPU processing time or a checksum process of the protocol into a hardware engine and offloading from the CPU is known (for example, patents). Reference 1).

In a network offload engine configured by hardware, some fields of the IP header, for example, a field such as TOS (Type Of Service) may have a fixed value due to a reduction in circuit scale or the like. . In such a case, it has been difficult to change the value of the TOS field, which is a fixed value, from the outside. Therefore, it has been difficult to perform quality of service (QOS) control based on the value of the TOS field in a communication apparatus including such a network offload engine.
Embodiments of the present invention have been made in view of the above problems, and provide a communication device that facilitates QOS control based on the value of a TOS field in a communication device including a network offload engine. Objective.

  In order to solve the above problem, a communication device according to an embodiment includes an offload engine that processes at least a part of network protocol processing including generation of a transmission packet, and an offload engine that responds to a request from an application. An offload engine control unit that controls generation of the transmission packet; and a setting update unit that rewrites a quality control parameter of the transmission packet generated by the offload engine according to the control to a value specified by the application. .

  According to the present embodiment, it is possible to provide a communication device that facilitates QOS control based on the value of the TOS field in a communication device including a network offload engine.

It is a hardware block diagram of the communication apparatus which concerns on 1st Embodiment. It is a figure for demonstrating the relationship between the packet and TOS value which the offload engine which concerns on 1st Embodiment produces | generates. It is a functional lineblock diagram of the off-road engine driver concerning a 1st embodiment. It is a flowchart of the starting process of the packet generation which concerns on 1st Embodiment. It is a flowchart of the rewriting process of the TOS value which concerns on 1st Embodiment. It is a figure which shows the structure of the IP header of an IPv4 format. It is a flowchart of the packet transmission process which concerns on 1st Embodiment. It is an example of the conversion table of a TOS value and an access category. It is a figure which shows an example of the frame format of wireless LAN. It is a block diagram of the communication system which concerns on 2nd Embodiment.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

[First Embodiment]
FIG. 1 is a hardware configuration diagram of a communication apparatus 100 according to the first embodiment. The communication apparatus 100 includes a CPU (Central Processing Unit) 101, a shared memory 102, a DMA (Direct Memory Access) controller 103, an offload engine 104, and a wireless LAN (Local Area Network) interface (hereinafter referred to as a wireless LAN I / F). 106, a memory 107, a first bus 109, and a second bus 108.

  The CPU 101, shared memory 102, DMA controller 103, offload engine 104, and wireless LAN I / F 106 are connected to each other via a first bus. Further, the CPU 101 is connected to the memory 107 via the second bus. The first and second buses transmit addresses, data, various control signals, and the like.

  The CPU 101 is an arithmetic device that implements each function included in the communication device 100 by reading a program or data from the memory 107 or the like via the second bus and executing the processing. The memory 107 is a storage unit such as a RAM (Random Access Memory), a flash ROM (Read Only Memory), and an HDD (Read Only Memory). The memory 107 stores various programs such as an OS (Operating System), applications, and drivers executed by the CPU 101 and at least a part of data used by the various programs, and is used as a work area of the CPU 101. In addition, the CPU 101 performs control related to network communication via the first bus.

  The offload engine 104 performs at least a part of network protocol processing, for example, generation of a transmission packet, checksum processing, and the like. The offload engine 104 is configured by, for example, hardware, and transmits communication data such as packet data for transmission and a payload of a received packet to a shared memory by a DMAC (Direct Memory Access Controller) 105 provided therein. Transfer to / from 102.

  The wireless LAN I / F 106 is, for example, a module including hardware for performing wireless LAN communication conforming to the IEEE 802.11 standard and firmware for controlling the hardware.

  In the above configuration, the shared memory 102 and the memory 107 are connected to different buses. Therefore, for example, even when the offload engine 104 writes data to the shared memory 102, the access to the memory 107 of the CPU 101 is not affected. The DMA controller 103 performs data transfer between the shared memory 102 and the wireless LAN I / F 106, and the DMAC 105 performs data control between the shared memory 102 and the offload engine 104. For this reason, the load related to the data transfer of the CPU 101 can be reduced.

  FIG. 2 is a diagram for explaining an outline of the configuration and operation related to the off-road engine 104. A plurality of programs including an OS 201, one or more applications 202, 203, 204, and an offload engine driver 209 are operating on the CPU 101.

  The applications 202 to 204 are applications that perform network communication, and the applications 202 and 203 have TOS values 205 and 206 that are parameters for controlling communication quality in accordance with the respective purposes. The off-road engine driver 209 is a driver that controls the off-road engine 104.

  The applications 202 to 204 can request processing from the offload engine 104 by using an application programming interface (hereinafter referred to as API) 208 using a predefined function. The OS 201 executes a plurality of software including the applications 202 to 204 and the offload engine driver 209 in parallel as processes.

  In FIG. 2, for example, when the application 202 uses the offload engine 104, first, the offload engine driver 209 is requested to generate a socket 213 that is a virtual communication interface for the application 202. The socket 213 has identification information 210 for identifying the application 202 that has requested the generation of the socket 213. The identification information 210 includes information such as a destination IP address, a source IP address, a destination port, a source port, and a protocol specified by the application 202, for example.

  On the other hand, when the application 202 requests transmission of data via the socket 213, the offload engine 104 generates, for example, IP packets 216 and 217 and stores them in the shared memory 102 under the control of the offload engine driver 209. . Here, the IP header of the IP packets 216 and 217 generated by the request of the application 202 includes the same destination IP address, source IP address, and protocol as the identification information 210. The TCP headers of the TCP packets 219 and 220 include the same destination port and transmission source port as the identification information 210.

  Similarly, the IP header of the IP packet 218 generated via the socket 214 requested to generate by specifying the identification information 211 by the application 203 includes the same destination IP address, transmission source IP address, and The protocol is included. Also, the TCP header of the TCP packet 221 includes the same destination port and transmission source port as the identification information 211.

  Accordingly, the offload engine driver 209 identifies the requesting application of the generated IP packet by comparing the identification information 210 and 211 with the IP header and TCP header of the generated IP packets 216 to 218 and the like. Can do.

  FIG. 3 is a functional configuration diagram of the off-road engine driver 209. The offload engine driver 209 includes an interface generation unit 301, an offload engine control unit 302, a setting update unit 303, a checksum calculation unit 304, and a transmission control unit 305. The interface generation unit 301 generates a socket interface in response to a request from one or a plurality of applications 202 and 203.

  The offload engine control unit 302 sets registers, descriptors, and the like for operating the offload engine 104 and requests the offload engine 104 to generate a packet. Further, the fact that the packet generated by the offload engine 104 has been written to the shared memory 102 is detected by, for example, a packet generation completion interrupt or the like, and the address of the generated packet is acquired from the register of the offload engine 104 or the like. .

  The setting update unit 303 rewrites the TOS value of the packet stored in the shared memory 102 to the TOS value associated with the identification information based on the identification information. When the checksum of the IP header needs to be updated due to the rewriting of the TOS value, the checksum calculation unit 304 calculates the checksum of the IP header and updates the checksum field of the IP header.

  The transmission control unit 305 converts the generated packet into a DIX format frame and requests the wireless LAN I / F 106 to transmit the frame.

  With the above configuration, for example, when the application 202 specifies the identification information 210 and the TOS value 205 and requests data transmission, the interface generation unit 301 generates IP packets 216, 217, and the like. The setting update unit 303 compares the IP header, TCP header, and the like of the generated IP packets 216 and 217 with the identification information 210, and if the predetermined information matches, the setting update unit 303 sets the TOS value 205 associated with the identification information 210. The TOS value of the IP packet 216, 217 is overwritten. Furthermore, the checksum calculation unit 304 recalculates the checksum of the IP header of the IP packets 216 and 217 as necessary, and updates the checksum field of the IP header.

  With the above configuration, even when the offload engine 104 cannot change the TOS value of the IP packets 216 and 217 due to hardware limitations, the TOS value of the IP header of the IP packets 216 and 217 can be set. It becomes. Therefore, in the communication device 100 including the offload engine 104, QOS control based on the value of the TOS field can be facilitated.

  Next, the operation of the communication apparatus 100 will be described with reference to FIGS. FIG. 4 is a flowchart of packet generation start processing according to the first embodiment. Here, as an example, a case will be described in which the application 202 illustrated in FIG. 2 specifies the identification information 210 to request generation of the socket 213 and the offload engine 104 generates the IP packet 216.

  In FIG. 4, when the application 202 designates the TOS value 205 and transmits a packet, the application 202 designates the identification information 210 and requests the offload engine driver 209 to generate a socket (step). S401). The identification information 210 includes, for example, a destination IP address, a source IP address, a destination port, a source port, a protocol, a TOS value 205, and the like. The identification information 210 may be generated by the interface generation unit 301 of the offload engine driver 209 based on the information specified by the application 202.

  The interface generation unit 301 generates a socket 213 having identification information 210 in response to a request from the application 202 (step S402). The socket is an API that provides a virtual communication interface for an application to perform communication using a protocol such as TCP or UDP (User Datagram Protocol). Each application can set an IP address and a port number of a communication destination using a socket interface, and can request data transmission / reception. The socket interface is an example of an API used for communication, and may use another API.

  The interface generation unit 301 determines whether a TOS value is specified when the socket 213 is generated (step S403). When the TOS value 205 is specified, the interface generation unit 301 stores the identification information 210 and the TOS value 205 in association with each other (step S404).

  When the socket 213 is generated, the application 202 requests the offload engine driver 209 to generate a packet (step S405). In response to the request from the application 202, the offload engine control unit 302 sets registers, descriptors, and the like for operating the offload engine 104, and instructs the offload engine 104 to start generating packets (step S406).

  With the above operation, the offload engine 104 starts generating the IP packet 216 corresponding to the socket 213.

  Next, FIG. 5 shows a flowchart of a TOS value rewrite process according to an embodiment. When the offload engine control unit 302 detects an interrupt indicating that a packet is generated from the offload engine 104 (step S501), the offload engine control unit 302 acquires the address of the generated packet from the register of the offload engine 104 (step S502). ). The setting update unit 303 extracts the destination IP address, the source IP address, and the protocol from the IP header of the IP packet 216 based on the acquired address, and similarly extracts the destination port and the source port from the TCP header (step S503).

  The setting update unit 303 compares each piece of data extracted in step S503 with the identification information 210, and determines, for example, whether all items match (step S504). At this time, when a socket other than the socket 213, for example, the socket 214 corresponding to the application 203 in FIG. 2 is generated, the identification information 211 is similarly compared. If the data extracted in step S503 matches the identification information 210, the setting update unit 303 updates the value of the quality control parameter of the IP header of the IP packet 216 with the TOS value 205 associated with the identification information 210. (Step S505).

  Here, the quality control parameters of the IP header will be described. FIG. 6 is a diagram illustrating a configuration of an IPv4 format IP header as an example of an IP header. The IP packet is composed of an IP header 601 and an IP payload 602. Various information shown in FIG. 6 is stored in the IP header, and the field of Type Of Service (TOS) 603 corresponds to the value of the quality control parameter. When updating the value of the quality control parameter, the setting update unit 303 overwrites the value of this Type Of Service (TOS) 603 field with the TOS value 205 or the like.

  In the IPv4 format IP header, the IP header checksum value is stored in the Header Checksum 604 field. Therefore, when the TOS 603 field of the IPv4 format IP header 601 is rewritten, it is necessary to recalculate the checksum of the IP header 601 and update the value of the Header Checksum 604 field.

  On the other hand, when the IP header is an IPv6 format IP header, the configuration of the IP header is different, and the Traffic Class field corresponds to the value of the quality control parameter. Therefore, when the setting update unit 303 updates the value of the quality control parameter, the value of the TOS 603 field in the IPv4 format IP header and the value of the Traffic Class field in the IPv6 format IP header are set to the TOS value 205 or the like. Overwrite. Note that since the checksum of the header is omitted in the IPv6 format IP header, it is not necessary to recalculate and update the checksum of the IP header.

  Here, returning to FIG. 5, the description of the TOS value rewriting process will be continued. In step S505 of FIG. 5, after updating the quality control parameter value of the IP packet 218, the checksum calculation unit 304 recalculates the checksum of the IP header as necessary, and updates the checksum of the IP header. . For example, in the case of an IPv4 format IP header, the checksum calculation unit 304 recalculates the checksum of the IP header 601 and overwrites the recalculated checksum in the Header Checksum 604 field. On the other hand, in the case of an IPv6 format IP header, the checksum calculator 304 can omit the checksum calculation and / or update. Note that the IP headers in the IPv4 format and the IPv6 format exemplified above are examples, and this embodiment can be applied to packets and headers in other formats.

  Next, packet transmission processing of the communication device 100 will be described. FIG. 7 is a flowchart of packet transmission processing according to the first embodiment. The transmission control unit 305 converts the IP packet 216 in which the TOS value 205 is rewritten and the checksum is updated as necessary into an Ethernet (registered trademark) frame such as a DIX format, for example (step S701). Next, the transmission control unit 305 requests the wireless LAN I / F 106 to transmit the frame converted into the Ethernet frame (step S702). Upon receiving the request, the wireless LAN I / F 106 converts the frame requested for transmission into a wireless LAN format frame (step S703). Furthermore, the wireless LAN I / F 106 converts the upper 3 bits of the TOS field included in the IP header of the frame requested to be transmitted into an access category value defined in the wireless LAN standard such as IEEE802.11e. (Step S704).

FIG. 8 is an example of a conversion table 801 for TOS values and access categories. For example, the wireless LAN I / F 106 converts the value of the TOS priority 802 into the value of an access category (hereinafter referred to as AC) 803 based on such a table.

  Here, returning to FIG. 7, the description of the packet transmission process is continued. For example, the wireless LAN I / F 106 sets the AC 803 value converted based on the conversion table 801 in the quality control field of the wireless LAN frame (step S705).

  FIG. 9 shows a format of a wireless LAN frame 901 in the IEEE 802.11e format as an example of the wireless LAN frame format. The wireless LAN frame 901 includes an IEEE 802.11e Header 902, and the IEEE 802.11e Header 902 has a QoS Control 904 field. For example, the wireless LAN I / F 106 sets the value of the AC 803 converted into the QoS Control 904 field. Also, for example, an IP packet is stored in the Data 903 field of the wireless LAN frame 901.

  Returning to FIG. 7 again, the wireless LAN I / F 106 transmits the generated wireless LAN frame 901 (step S706).

  As described above, according to the present embodiment, the setting update unit 303 updates the value of the quality control parameter of the IP packet 216 generated by the offload engine 104 to a value specified by the application 202. In addition, the checksum calculation unit 304 recalculates the checksum of the IP header in which the quality control parameters are updated as necessary, and updates the checksum field of the IP header. Therefore, the wireless LAN I / F 106 can set the quality control field of the wireless LAN frame based on the quality control parameter of the IP header. That is, in the communication apparatus 100 including the offload engine 104, QOS control based on the value of the TOS 603 field can be facilitated.

[Second Embodiment]
In the first embodiment, an example in which the communication apparatus 100 includes the wireless LAN I / F 106 has been described. However, the communication apparatus 100 does not necessarily have the function of the wireless LAN I / F 106.

  FIG. 10 is a configuration diagram of a communication system 1000 according to the second embodiment. The communication system 1000 includes a communication device 1001, a wireless LAN device 1003, and an information processing device 1004.

  The communication device 1001 includes a network interface (hereinafter referred to as a network I / F) 1002 instead of the wireless LAN I / F 106 of the communication device 100 according to the first embodiment. Other configurations are the same as those of the communication device 100. The network I / F 1002 outputs the Ethernet frame, such as the DIX format, generated in step S701 in FIG. 7 of the first embodiment without converting it to a wireless LAN format frame.

  The wireless LAN device 1003 has a function corresponding to the wireless LAN I / F 106 or the wireless LAN I / F 106 according to the first embodiment. The wireless LAN device 1003 converts the Ethernet frame transmitted from the communication device 1001 into a wireless LAN format frame, and converts the TOS value of the IP header included in the Ethernet frame into a wireless LAN access category. Further, the value of the access category is set in the quality control parameter field of the wireless LAN frame, for example, the QoS Control 904 field of the IEEE802.11e Header 902 and transmitted to the information processing apparatus 1004.

  With the above configuration, the same effect as in the first embodiment can be obtained.

  In addition, the said structure is an example to the last, and it cannot be overemphasized that there are various system structural examples according to a use and the objective. For example, the communication device 1001 may have an extended interface such as a USB (Universal Serial Bus) interface instead of the network I / F 1002, and the wireless LAN device 1003 may be a wireless LAN interface connected to the USB interface. . At this time, the wireless LAN interface may create a wireless LAN frame by omitting the conversion to the Ethernet frame in step S701 in FIG. 7 of the first embodiment.

100 communication device 103 DMAC
DESCRIPTION OF SYMBOLS 104 Offload engine 106 Wireless LAN interface 301 Interface production | generation part 302 Offload engine control part 303 Setting update part 304 Checksum calculation part 305 Transmission control part 1000 Communication system

Japanese Patent No. 3966307

Claims (10)

An offload engine that handles at least part of the network protocol processing, including the generation of outgoing packets;
An offload engine control unit that controls generation of the transmission packet of the offload engine in response to a request from an application;
A setting update unit that rewrites the quality control parameter of the transmission packet generated by the offload engine according to the control to a value specified by the application;
A communication device. An interface generation unit that generates a virtual communication interface corresponding to the identification information specified by the application;
The communication apparatus according to claim 1, wherein the setting update unit rewrites the quality control parameter based on the identification information.   The communication apparatus according to claim 2, wherein the virtual communication interface is a socket interface.   The communication apparatus according to any one of claims 1 to 3, further comprising a checksum calculation unit that recalculates a checksum of a packet in which the setting update unit rewrites the quality control parameter.   The communication apparatus according to claim 4, wherein the transmission packet is an IP packet having an IPv4 format IP header, and the quality control parameter is a value of Type Of Service.   The communication device according to any one of claims 1 to 3, wherein the transmission packet is an IP packet having an IPv6 format IP header, and the quality control parameter is a value of Traffic Class.   7. The communication according to claim 1, further comprising: a wireless LAN interface unit that converts the quality control parameter into a wireless LAN access category and sets the access category in a quality control field of the wireless LAN frame. apparatus. A CPU that performs processing related to the application, the offload engine control unit, and the setting update unit, the offload engine, and a first memory that stores data related to the transmission packet are connected to each other. With bus,
A second bus to which the CPU and a program executed by the CPU and a second memory storing at least a part of data used by the program are connected;
The communication apparatus according to any one of claims 1 to 6, further comprising: A network interface unit connected to the first bus;
A DMA controller connected to the first bus;
A data transfer means for performing data transfer between the first memory and the network interface unit by the DMA using the DMA controller;
The communication device according to claim 8, comprising: An offload engine that handles at least part of the network protocol processing, including the generation of outgoing packets;
An offload engine control unit that instructs generation start of the transmission packet of the offload engine in response to a request from an application;
A setting update unit for rewriting the quality control parameter of the transmission packet generated by the offload engine according to the instruction to a value specified by the application;
A wireless LAN interface that converts the quality control parameter into a wireless LAN access category, and sets the access category in a quality control field of the wireless LAN frame;
A communication system.

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