JP2012070425A - Protocol conversion apparatus and protocol conversion method used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protocol conversion apparatus capable of eliminating intervention by a CPU to lower processing load for the CPU.SOLUTION: A protocol conversion apparatus (1) includes a comparison data extraction circuit (13), a comparison determination circuit (14), a converted data computation circuit (15), a coprocessor (18), a memory (19), and a memory supervisory circuit (20). The comparison data extraction circuit (13) extracts a specific part of a received frame. The comparison determination circuit (14) compares the extracted data with data registered beforehand. The converted data computation circuit (15) computes data required for conversion processing of an IP header of the frame from the extracted data. The coprocessor (18) performs conversion of the IP header of the frame, based on the computation result of the converted data computation circuit and data in a conversion data table (17), according to the comparison result by the comparison determination circuit. The memory (19) stores data applied with the conversion of the IP header by the coprocessor. The memory supervisory circuit (20) controls to transmit the frame, based on the monitored result for the status of the frame stored in the memory.

Description

  The present invention relates to a protocol conversion apparatus and a protocol conversion method used therefor, and more particularly to protocol conversion of IPv4 (Internet Protocol version 4) and IPv6 (Internet Protocol version 6).

  Currently, networks using IPv6 are spreading, but since IPv4 networks are already widespread, IPv4 networks and IPv6 networks coexist. Since IPv4 and IPv6 are not compatible, protocol conversion is required to perform data communication between the IPv4 network and the IPv6 network. In general, a device that performs such protocol conversion is called a translator.

  In general, there is a translator configuration in which a received frame is analyzed by software and protocol conversion is performed (see, for example, Patent Document 1). In this case, a burden on a CPU (central processing unit) increases. ing.

JP 2003-163702 A JP 2005-117503 A

  Furthermore, in recent years, Ethernet (registered trademark) communication has been speeded up, and communication exceeding 1 Gbps has been performed, and the load on the CPU is high. In addition, since each interface is also speeded up, high processing capability is required of the CPU regardless of Ethernet (registered trademark).

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a protocol conversion apparatus and a protocol conversion method used therefor that can solve the above problems, eliminate the intervention of the CPU, and reduce the processing load on the CPU.

The protocol conversion apparatus according to the present invention includes a comparison data extraction circuit that extracts a specific portion of the frame in order to specify the type of the received frame;
An entry table for storing the characteristics of the received frame as the pre-registered data;
A comparison determination circuit that compares the data extracted by the comparison data extraction circuit with data registered in advance in the entry table;
A conversion data calculation circuit for calculating data necessary for conversion processing of an IP (Internet Protocol) header of the frame from data extracted by the comparison data extraction circuit;
A coprocessor for converting the IP header of the frame based on the calculation result of the conversion data calculation circuit and the data of the conversion data table storing the converted IP header data according to the comparison result of the comparison determination circuit; ,
A memory for storing data obtained by converting the IP header by the coprocessor;
A memory monitoring circuit that monitors the status of the frame stored in the memory and controls to transmit the frame in the case of a transmittable status;
A FIFO (First In First Out) for temporarily holding the received frame;
The coprocessor replaces an IPv4 (Internet Protocol version 4) header and an IPv6 (Internet Protocol version 6) header of the frame stored in the FIFO,
In protocol conversion between IPv4 and IPv6, all frame information management and conversion processes are performed by hardware using the above-described circuits.

In the protocol conversion method according to the present invention, the comparison data extraction circuit extracts a specific part of the frame in order to specify the type of the received frame.
The characteristics of the received frame are registered in the entry table in advance,
In the comparison determination circuit, the data extracted by the comparison data extraction circuit is compared with the data registered in advance in the entry table,
The conversion data calculation circuit calculates data necessary for the IP (Internet Protocol) header conversion processing of the frame from the data extracted by the comparison data extraction circuit.
In the coprocessor, the conversion of the IP header of the frame based on the calculation result of the conversion data calculation circuit and the data of the conversion data table storing the data of the converted IP header according to the comparison result of the comparison determination circuit And
Storing the data obtained by converting the IP header by the coprocessor in a memory;
In the memory monitoring circuit, the status of the frame stored in the memory is monitored and controlled to transmit the frame in the case of a status that can be transmitted,
A FIFO (First In Fi) that temporarily holds the received frame.
rst Out)
The coprocessor replaces an IPv4 (Internet Protocol version 4) header and an IPv6 (Internet Protocol version 6) header of the frame stored in the FIFO;
In protocol conversion between IPv4 and IPv6, all frame information management and conversion processes are performed by hardware using the above-described circuits.

  By adopting the configuration and operation as described above, the present invention can eliminate the CPU and reduce the processing load on the CPU.

It is a block diagram which shows the structural example of the protocol converter by the 1st Embodiment of this invention. It is a flowchart which shows the protocol conversion process by the 1st Embodiment of this invention. It is a figure which shows the structural example of the IPv4 header used in the 1st Embodiment of this invention. It is a figure which shows the structural example of the IPv6 header used in the 1st Embodiment of this invention. It is a block diagram which shows the structural example of the descriptor used in the 1st Embodiment of this invention.

  Next, embodiments of the present invention will be described with reference to the drawings. First, the outline of the protocol conversion apparatus according to the present invention will be described. The protocol conversion apparatus according to the present invention includes a circuit that can perform all frame information management and conversion processing by hardware in protocol conversion between IPv4 (Internet Protocol version 4) and IPv6 (Internet Protocol version 6). Thus, the CPU can be removed and the processing load on the CPU can be reduced.

  FIG. 1 is a block diagram showing a configuration example of a protocol conversion apparatus according to the first embodiment of the present invention. In FIG. 1, the protocol conversion apparatus 1 includes a LAN (Local Area Network) receiving unit 11, a FIFO (First In First Out) 12, a comparison data extraction circuit 13, a comparison determination circuit 14, a conversion data calculation unit 15, and the like. , An entry table register 16, a conversion data table register 17, a coprocessor 18, a memory 19, a memory monitoring circuit 20, and a LAN transmission unit 21.

  The LAN receiving unit 11 receives an Ethernet (registered trademark) frame from an Ethernet (registered trademark) line. The FIFO 12 temporarily holds the frame received by the LAN receiving unit 11.

  The comparison data extraction circuit 13 extracts a specific part of the received frame in order to specify the type of the received frame. The comparison determination circuit 14 compares the data extracted by the comparison data extraction circuit 13 with the data of the entry table register 16.

  The conversion data calculation unit 15 calculates data necessary for the conversion process from the data extracted by the comparison data extraction circuit 13. The entry table register 16 stores characteristics of the frame received by the LAN receiving unit 11, for example, comparison data such as an IP (Internet Protocol) version and an IP address. The conversion data table register 17 stores the IP header data after conversion.

  The coprocessor 18 converts the IP header of the frame. The memory 19 stores the data converted by the coprocessor 18. The memory monitoring circuit 20 monitors the status of the frame stored in the memory 9, and transmits the frame to the Ethernet (registered trademark) line through the LAN transmission unit 21 if the transmission is possible. The LAN transmission unit 21 transmits the data converted by the coprocessor 18 to the Ethernet (registered trademark) line.

  FIG. 2 is a flowchart showing the protocol conversion processing according to the first embodiment of the present invention, FIG. 3 is a diagram showing a configuration example of the IPv4 header used in the first embodiment of the present invention, and FIG. It is a figure which shows the structural example of the IPv6 header used in the 1st Embodiment of this invention.

  FIG. 5 is a block diagram showing a configuration example of the descriptor used in the first embodiment of the present invention. The protocol conversion processing according to the first embodiment of the present invention will be described with reference to FIGS.

  The operation of the protocol conversion apparatus 1 having the features of the present invention when it receives an IPv4 frame and converts it into an IPv6 frame and transmits it or when it receives an IPv6 frame and converts it into an IPv4 frame and transmits it follows FIG. I will explain.

  The frame is received through the LAN receiver 11. The received frame is stored in the FIFO 12, but at the same time, the determination part (including the IP version) of the frame is extracted through the comparison data extraction circuit 13 to determine whether it is IPv4, IPv6 or other. The determination part can be determined by hardware by specifying an offset from the top of the Ethernet (registered trademark) frame.

  When the determination part of the received frame is IPv4 and the conditions of the other entry table register 16 match, the coprocessor 18 replaces the IPv4 header part of the frame stored in the FIFO 12 with the IPv6 header. Information on the header to be replaced is set in the conversion data table register 17. The frame whose header has been changed is stored in the memory 19 by DMA (Direct Memory Access), and is transmitted to the Ethernet (registered trademark) line through the LAN transmission unit 21.

  When the determination part of the received frame is IPv6 and the conditions of the other entry table register 16 are met, the coprocessor 18 replaces the IPv6 header part of the frame stored in the FIFO 12 with the IPv4 header. Information on the header to be replaced is set in the conversion data table register 17. The frame whose header has been changed is stored in the memory 19 by the DMA, and transmitted to the Ethernet (registered trademark) line through the LAN unit 21.

  As shown in FIG. 5, the frames stored in the memory 19 are managed by descriptors # 1 to #N. The memory monitoring circuit 20 monitors the statuses of the descriptors # 1 to #N, and transmits a frame to the Ethernet (registered trademark) line through the LAN transmission unit 21 if the statuses are transmittable.

  As described above, in this embodiment, it is possible to realize protocol conversion between IPv4 and IPv6 by using hardware without any CPU intervention, so that the processing load on the CPU can be reduced.

  The protocol conversion process according to this embodiment will be described with reference to the flowchart shown in FIG.

  When receiving the Ethernet (registered trademark) frame from the line (step S1 in FIG. 2), the protocol conversion apparatus 1 stores the received frame in the FIFO 12 (step S2 in FIG. 2). Regarding the reception of the frame, the protocol conversion apparatus 1 performs reception using a function (not shown) necessary for a general Ethernet (registered trademark) frame reception operation.

  At the same time, the protocol conversion apparatus 1 extracts a comparison portion for discriminating the frame type and the like by the comparison data extraction circuit 13 (step S3 in FIG. 2). In general, an IP frame has a configuration as shown in FIGS. 3 and 4, but the entry data is compared by extracting the EtherType in the MAC (Media Access Control) header or the IP version portion in the IP header. To do.

  Other than the version, the MAC address, the IP address, the IP protocol, the NEXT header, and the like are registered in the entry table register 16 as the frame to be converted, and the extracted comparison portion data and the entry table register 16 are registered. Compare with the registered data.

  Since some frames have a PPPoE [Point to Point Protocol over Ethernet (registered trademark)] header or the like added thereto, the comparison data extraction circuit 13 first looks at the EtherType of the MAC header to determine the type of the frame. Has a function of extracting a necessary comparison portion.

  The protocol converter 1 compares the comparison data extracted by the comparison data extraction circuit 13 with the value of the entry table register 16 (step S4 in FIG. 2), and if these data match (step S5 in FIG. 2), the IP When the frame is a header conversion target and the version is determined to be IPv4 by the version determination (step S6 in FIG. 2), the value calculated by the conversion data calculation unit 15 or the data stored in the conversion data table register 17 The coprocessor 18 replaces the IPv4 header of the frame stored in the FIFO 12 with the IPv6 header (step S7 in FIG. 2).

  The replacement from the IPv4 header to the IPv6 header can be realized as follows.

  “IP version” is fixedly converted to IPv6. As for “TrafficClass”, the TOS (Type Of Service) value of the IPv4 header of the received data is copied and set as the value of “TrafficClass”. As for “FlowLabel”, a value set in advance in the conversion data table register 17 is set as a value of “FlowLabel”.

  For “PayloadLength”, the value calculated by the conversion data calculation unit 15 from the values of IP LEN (length) and IP HLEN (header length) in the IP header of the received frame is set as the value of “PayloadLength”. For “NextHeader”, the value of “IP PROTO (protocol)” of the received data is copied and set as the value of “NextHeader”.

  As for “HopLimit”, a value obtained by subtracting 1 from the value of “IP TTL (Time To Live)” of the received data by the conversion data calculation unit 15 is set as the value of “HopLimit”. For “IPv6 SRC (Source Address)” and “IPv6 DST (Destination Address)”, values set in advance in the entry table register 16 are used.

  As described above, the IPv6 header data shown in FIG. 4 for conversion is aligned. In the protocol conversion apparatus 1, the coprocessor 18 converts the IPv4 header into the IPv6 header using these values.

  The protocol conversion device 1 DMA-transfers the data converted into IPv6 to the memory 19 (step S8 in FIG. 2). In the memory 19, as shown in FIG. 5, data and descriptors are managed on a one-to-one basis. For the descriptor, a data address, length, and control information are used. The control information includes a flag indicating whether or not there is transmission data. A flag is set when the frame is DMAed on the memory 19, and the memory monitoring circuit 20 monitors the flag.

  If the flag is set, the memory monitoring circuit 20 recognizes that there is a transmission frame after the protocol conversion, DMAs the frame, and transmits it through the LAN transmission unit 21 (step S9 in FIG. 2). When the frame is transmitted, the memory monitoring circuit 20 disables the descriptor flag.

  When processing the descriptor # 1, the memory monitoring circuit 20 monitors the descriptor in order and transmits a frame in an operation such as monitoring the descriptor # 2. In FIG. 5, N descriptors are ring-managed.

  When it is determined that the version is IPv6 in the version determination (steps S6 and S10 in FIG. 2), the protocol conversion device 1 calculates the value calculated by the conversion data calculation unit 15 and the data stored in the conversion data table register 17 The coprocessor 18 replaces the IPv6 header of the frame stored in the FIFO 12 with the IPv4 header (step S11 in FIG. 2).

  The replacement from the IPv6 header to the IPv4 header can be realized as follows.

  “IP version” is fixedly converted to IPv4. For “IP HLEN”, the normal IPv4 header length 20 (d) is used as “IP HLEN”. When “IPv4 option” or the like is added, the header length does not become 20 (d), so it is not targeted.

  When the IP header length of the received frame is not 20 (d) in the comparison / determination circuit 14, the received frame may be DMA-processed in the memory 19 without being converted, and then processed by software.

  For “TOS”, the “TrafficClass” value of the received frame is used as “TOS”. For “IP LEN”, a value obtained by calculating the IPv4 packet length by the conversion data calculation unit 15 from “PayloadLength” of the received frame and “IP LEN (fixed value 20)” of the IPv4 header is set to “PayloadLength”.

  As for “ID (Identification)”, the converted data calculation unit 15 calculates a value obtained by sequentially incrementing a value from a certain number for each received frame so that the value changes for each frame, and sets the ID value.

  For “FLAG”, the value set in the entry table register 16 is used as the FLAG value. The FLAGMENT frame is not targeted and is fixed to 0. For “IP TTL”, the conversion data calculation unit 15 sets “IP TTL” to a value obtained by subtracting 1 from “HopLimit” of the received frame.

  For “IP PROTO”, the value of “NextHeader” in the received frame is copied to “IP PROTO”. As for “IP CKSUM (checksum)”, the check sum of the IP header after conversion is calculated by the conversion data calculation unit 15 and the value is used.

  As described above, the IPv4 header data shown in FIG. 3 for the conversion is prepared. In the protocol conversion apparatus 1, the coprocessor 18 converts the IPv6 header into the IPv4 header using these values.

  The data converted into IPv4 is DMA-transferred to the memory 19 (step S12 in FIG. 2). In the memory 19, as shown in FIG. 5, data and descriptors are managed on a one-to-one basis. For the descriptor, a data address, length, and control information are used. The control information includes a flag indicating whether or not there is transmission data. A flag is set when the frame is DMAed on the memory 19, and the memory monitoring circuit 20 monitors the flag.

  If the flag is set, the memory monitoring circuit 20 recognizes that there is a transmission frame after the protocol conversion, DMAs the frame, and transmits it through the LAN transmission unit 21 (step S13 in FIG. 2). When the frame is transmitted, the memory monitoring circuit 20 disables the descriptor flag.

  When processing the descriptor # 1, the memory monitoring circuit 20 monitors the descriptor in order and transmits a frame in an operation such as monitoring the descriptor # 2. In FIG. 5, N descriptors are ring-managed.

  When the comparison data extracted from the received frame does not match the set value of the entry table register 16 (step S5 in FIG. 2), the protocol conversion device 1 DMA-transfers the data in the FIFO 12 to the memory 19 as it is (step S14 in FIG. 2). Since this frame is not subject to protocol conversion, it is appropriately processed by software (step S15 in FIG. 2).

  In the above embodiment, the descriptor is managed by a ring in the above embodiment as shown in FIG. 5, but a link pointer may be provided in the descriptor and managed by a link.

1 Protocol converter 11 LAN receiver 12 FIFO
DESCRIPTION OF SYMBOLS 13 Comparison data extraction circuit 14 Comparison determination circuit 15 Conversion data calculation part 16 Entry table register 17 Conversion data table register 18 Coprocessor 19 Memory 20 Memory monitoring circuit 21 LAN transmission part

Claims (6)

A comparison data extraction circuit for extracting a specific part of the frame in order to specify the type of the received frame;
An entry table for storing the characteristics of the received frame as the pre-registered data;
A comparison determination circuit that compares the data extracted by the comparison data extraction circuit with data registered in advance in the entry table;
A conversion data calculation circuit for calculating data necessary for conversion processing of an IP (Internet Protocol) header of the frame from data extracted by the comparison data extraction circuit;
A coprocessor for converting the IP header of the frame based on the calculation result of the conversion data calculation circuit and the data of the conversion data table storing the converted IP header data according to the comparison result of the comparison determination circuit; ,
A memory for storing data obtained by converting the IP header by the coprocessor;
A memory monitoring circuit that monitors the status of the frame stored in the memory and controls to transmit the frame in the case of a transmittable status;
A FIFO (First In First Out) for temporarily holding the received frame;
The coprocessor replaces an IPv4 (Internet Protocol version 4) header and an IPv6 (Internet Protocol version 6) header of the frame stored in the FIFO,
In the protocol conversion between the IPv4 and the IPv6, all the frame information management and conversion processing are performed by hardware using the above-described circuits. 2. The protocol conversion apparatus according to claim 1, wherein the entry table stores an IP version and an IP address as characteristics of the received frame.   3. The protocol conversion apparatus according to claim 1, wherein the memory monitoring circuit manages transmission of the frame with a descriptor. In the comparison data extraction circuit, a specific part of the frame is extracted in order to specify the type of the received frame,
The characteristics of the received frame are registered in the entry table in advance,
In the comparison determination circuit, the data extracted by the comparison data extraction circuit is compared with the data registered in advance in the entry table,
The conversion data calculation circuit calculates data necessary for the IP (Internet Protocol) header conversion processing of the frame from the data extracted by the comparison data extraction circuit.
In the coprocessor, the conversion of the IP header of the frame based on the calculation result of the conversion data calculation circuit and the data of the conversion data table storing the data of the converted IP header according to the comparison result of the comparison determination circuit And
Storing the data obtained by converting the IP header by the coprocessor in a memory;
In the memory monitoring circuit, the status of the frame stored in the memory is monitored and controlled to transmit the frame in the case of a status that can be transmitted,
A FIFO (First In Fi) that temporarily holds the received frame.
rst Out)
The coprocessor replaces an IPv4 (Internet Protocol version 4) header and an IPv6 (Internet Protocol version 6) header of the frame stored in the FIFO;
A protocol conversion method characterized in that in protocol conversion between the IPv4 and the IPv6, all frame information management and conversion processes are performed by hardware using the above-described circuits.   5. The protocol conversion method according to claim 4, wherein the entry table stores an IP version and an IP address as characteristics of the received frame.   6. The protocol conversion method according to claim 4, wherein the memory monitoring circuit manages transmission of the frame by a descriptor.

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