WO2018177184A1

WO2018177184A1 - Method and device for implementing table lookup processing, apparatus, and storage medium

Info

Publication number: WO2018177184A1
Application number: PCT/CN2018/079946
Authority: WO
Inventors: 王林滨
Original assignee: 深圳市中兴微电子技术有限公司
Priority date: 2017-03-31
Filing date: 2018-03-22
Publication date: 2018-10-04
Also published as: CN108664518B; CN108664518A

Abstract

A method and device for implementing table lookup processing, an apparatus, and a storage medium. The method comprises: determining whether an entry exists according to a key value of the entry by means of a cyclic redundancy check (CRC) polynomial calculation (100); when it is determined that the entry exists, determining a matching table address according to the CRC polynomial calculation result (101); determining an off-chip hash table lookup address according to a result returned after table lookup is performed on a matching table according to the determined matching table address (102); and performing table lookup according to the determined off-chip hash table lookup address to obtain a hash table lookup return key value, and performing table lookup processing according to whether the key value of the entry is consistent with the hash table lookup return key value (103).

Description

Method, device, device and storage medium for realizing table lookup processing

Cross-reference to related applications

The present application is filed on the basis of the Chinese Patent Application No. PCT Application No. PCT Application No. .

Technical field

The present invention relates to, but is not limited to, data processing technology, and more particularly to a method, device, device, and storage medium for implementing table lookup processing.

Background technique

With the development of network technology, the number of related entry items that the network switch chip needs to support is increasing, considering content addressable memory (CAM) and ternary content addressable memory (TCAM). The cost factor, in the case of a large number of items, the related technology generally uses a double-rate synchronous dynamic random access memory (DDR, Double Data Rate) method for table lookup processing.

Since the external DDR needs to consume more pin resources, the number of external DDRs will be limited. If the number of DDRs is limited, the number of DDR accesses needs to be reduced, and the hash (HASH) is not checked. If you need to check the table multiple times, if multiple entries coexist in a group of DDRs, different tables need to check the table multiple times, which also needs to occupy a huge DDR access bandwidth, which limits the efficiency of the table lookup and blocks. The processing of the chip greatly reduces the processing performance of the chip.

In summary, when there are a large number of entry entries, there are problems such as excessive pin resources, bandwidth resources, and processing performance of the chip when performing table lookup.

Summary of the invention

The following is a summary of the subject matter described in detail herein. This Summary is not intended to limit the scope of the claims.

The embodiments of the present invention provide a method, a device, a device, and a storage medium for implementing a table lookup process, which can reduce the occupation of pin resources and bandwidth resources and avoid the impact on chip processing performance.

An embodiment of the present invention provides a method for implementing a table lookup process, including:

Determining whether an entry exists by a cyclic redundancy check CRC polynomial calculation according to the key KEY value of the entry;

When it is determined that the entry exists, the matching table address is determined according to the calculation result of the CRC polynomial;

Determining the off-chip hash HASH lookup table address according to the result of checking the matching table according to the determined matching table address;

According to the determined off-chip HASH lookup table address, the hash table is returned to obtain the KEY value, and the table is processed according to whether the KEY value of the entry and the hash table return the KEY value.

In other embodiments, determining whether the entry exists comprises:

Performing the CRC polynomial calculation by using the KEY value of the entry for a first preset time;

Using the calculation result of the 0th CRC polynomial as the address of the matching table to perform a table lookup;

Matching the result returned by the matching table lookup table with the calculation result of other CRC polynomials other than the 0th CRC;

When the result returned by the matching table lookup table matches the calculation result of other CRC polynomials other than the 0th CRC, it is determined that the entry exists.

In other embodiments, the table lookup processing according to whether the KEY value of the entry and the hash check table return the KEY value are consistent:

The KEY value of the entry is consistent with the hash table return KEY value, and the entry is returned; the KEY value of the entry is inconsistent with the hash table return KEY value, and the entry is determined to be missed.

In other embodiments, the method further includes:

If the result returned by the matching table lookup table does not match the calculation result of the other CRC polynomial except the 0th CRC, the entry is sent to the CPU of the central processing unit for processing, or the entry is based on Preset rules are processed.

In other embodiments, before the determining whether the entry exists by the cyclic redundancy check CRC polynomial calculation, the method further includes:

Setting a second preset mask MASK according to the entry related to the service;

For each entry, select a corresponding type of MASK according to the packet parsing result, service step, and/or application mode;

Filter the invalid KEY value in the entry according to the selected MASK;

The packet parsing result includes a packet type.

Configuring a third preset Bloom filter table;

Performing a CRC calculation on the KEY value of the entry to obtain a CRC result;

Use the CRC result to find all Bloom filter tables to get the filter table results;

Determining whether the entry exists according to the result of the filtering table;

When it is determined that the entry exists, the table continues to be checked, and when it is determined that the entry does not exist, the table check is stopped.

In other embodiments, the configuring the third preset one of the Bloom filter tables comprises:

The third predetermined one of the Bloom filter tables is configured according to the number of entries supporting the conflict.

On the other hand, the embodiment of the present invention further provides an apparatus for implementing a table lookup process, including: a first determining unit, a matching table address unit, a hash address unit, and a table lookup processing unit;

The first determining unit is configured to: determine, according to the key KEY value of the entry, whether the entry exists by using a cyclic redundancy check CRC polynomial calculation;

The matching table address unit is configured to: when determining the existence of the entry, determine the matching table address according to the calculation result of the CRC polynomial;

The hash address unit is configured to: determine an off-chip hash HASH lookup table address according to a result of performing a table lookup on the matching table according to the determined matching table address;

The lookup table processing unit is configured to: perform a lookup table according to the determined off-chip HASH lookup table address to obtain a hash check table to return a KEY value, and perform a table lookup according to whether the KEY value of the entry and the hash check table return a KEY value.

In other embodiments, the first determining unit is configured to:

In other embodiments, the lookup table processing unit is configured to:

Performing a lookup table according to the determined off-chip HASH lookup table address to obtain a hash table returning a KEY value, the KEY value of the entry is consistent with the return value of the hash table, and returning the entry; the KEY value of the entry And the hash table returns an inconsistency in the KEY value, determining that the entry misses.

In other embodiments, the lookup table processing unit is further configured to:

In other embodiments, the apparatus further includes a setting mask unit, a mask selection unit, and a filtering unit; wherein

Setting a mask unit is configured to: set a second preset mask MASK according to the entry related to the service;

The mask selection unit is configured to: select, for each entry, a corresponding type of MASK according to the packet parsing result, the service step, and/or the application mode;

The filtering unit is configured to: filter the invalid KEY value in the entry according to the selected MASK;

The packet parsing result includes a packet type.

In other embodiments, the apparatus further includes a configuration unit, a second calculation unit, a second lookup unit, a second determination unit, and a second processing unit;

The configuration unit is configured to: configure a third preset Bloom filter table;

The second calculating unit is configured to perform a CRC calculation on the KEY value of the entry to obtain a CRC result;

The second look-up table unit is configured to: find all the Bloom filter tables by using the CRC result, and obtain a filter table result;

The second determining unit is configured to: determine, according to the result of the filtering table, whether the entry exists;

The second processing unit is configured to: when it is determined that the item exists, continue to look up the table, and determine that the item does not exist, stop searching the table.

In other embodiments, the configuration unit is configured to:

Embodiments of the present invention provide an apparatus for implementing a table lookup process, including a memory and a processor, the memory storing a computer program executable on a processor, and the processor implementing the program when the program is executed The steps in the method of implementing table lookup processing.

Embodiments of the present invention provide a computer readable storage medium having stored thereon a computer program that, when executed by a processor, implements the steps in the method for implementing a lookup table process.

Compared with the related art, the technical solution of the present application includes: determining, according to a key (KEY) value of an entry, whether an entry exists by a cyclic redundancy check (CRC) polynomial calculation; determining that the entry exists, determining a match according to a calculation result of the CRC polynomial Table address; determining the off-chip hash (HASH) lookup table address according to the result of checking the matching table according to the determined matching table address; performing a lookup table according to the determined off-chip HASH lookup table address to obtain a hash table return The KEY value is checked according to the KEY value of the entry and whether the KEY value returned by the hash table is consistent. The method of the embodiment of the invention reduces the items that need to be looked up, reduces the occupation of the pin resources and the bandwidth resources, and avoids the impact on the processing performance of the chip.

Other features and advantages of the invention will be set forth in the description which follows, The objectives and other advantages of the invention may be realized and obtained by means of the structure particularly pointed in the appended claims.

DRAWINGS

The drawings are used to provide a further understanding of the technical solutions of the present invention, and constitute a part of the specification, which together with the embodiments of the present application are used to explain the technical solutions of the present invention, and do not constitute a limitation of the technical solutions of the present invention.

1 is a flowchart of a method for implementing table lookup processing according to an embodiment of the present invention;

2 is a flowchart of a method for implementing table lookup processing according to another embodiment of the present invention;

FIG. 3 is a flowchart of a method for implementing table lookup processing according to still another embodiment of the present invention; FIG.

4 is a structural block diagram of an apparatus for implementing table lookup processing according to an embodiment of the present invention;

FIG. 5 is a flowchart of a method for applying an example of the present invention; FIG.

FIG. 6 is a schematic diagram of a hardware entity of an apparatus for implementing table lookup processing according to an embodiment of the present invention.

detailed description

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments in the present application may be arbitrarily combined with each other.

The steps illustrated in the flowchart of the figures may be executed in a computer system such as a set of computer executable instructions. Also, although logical sequences are shown in the flowcharts, in some cases the steps shown or described may be performed in a different order than the ones described herein.

FIG. 1 is a flowchart of a method for implementing table lookup processing according to an embodiment of the present invention. As shown in FIG. 1, the method includes:

Step 100: Determine, according to a key (KEY) value of the entry, whether the entry exists by using a cyclic redundancy check (CRC) polynomial calculation;

In other embodiments, determining whether an entry exists includes:

Performing a first predetermined number of CRC polynomial calculations on the KEY value of the entry;

When the result returned by the matching table lookup table matches the calculation result of the other CRC polynomial except the 0th CRC, it is determined that the entry exists.

It should be noted that the first preset number can be determined by a person skilled in the art according to the number of items supporting conflicts.

Step 101: When determining that an entry exists, determine a matching table address according to a calculation result of a CRC polynomial;

Step 102: Determine, according to the determined matching table address, a result of performing a table lookup on the matching table, and determine an off-chip hash HASH lookup table address;

Step 103: Perform a lookup table according to the determined off-chip HASH lookup table address to obtain a hash check table return KEY value, and perform a table lookup process according to whether the KEY value of the entry and the hash check table return a KEY value.

In other embodiments, the table lookup processing according to the KEY value of the entry and the return of the KEY value by the hash table include:

The KEY value of the entry is consistent with the KEY value returned by the hash table, and the entry is returned; the KEY value of the entry is inconsistent with the KEY value returned by the hash table, and the entry is determined to be missed.

In other embodiments, the method of the embodiment of the present invention further includes:

If the result returned by the match table does not match the calculation result of the other CRC polynomial except the 0th CRC, the entry is sent to the CPU of the CPU for processing, or the entry is processed according to a preset rule. The matching table of the embodiment of the present invention can be set in an off-chip double rate synchronous dynamic random access memory (DDR).

In other embodiments, before the step 100, the method of the embodiment of the present invention may further include the process shown in FIG. 2:

Step 200: Set a second preset MASK according to the entry related to the service;

Step 201: Select, for each entry, a corresponding type of MASK according to the packet parsing result, the service step, and/or the application mode.

It should be noted that how to select a corresponding type of MASK can be analyzed and set by a person skilled in the art according to the packet analysis result, the service step, and/or the application mode.

Step 202: Filter an invalid KEY value in the entry according to the selected MASK.

The packet parsing result may include a packet type.

The embodiment of the invention reduces the occupation of the pin resources and the bandwidth resources by filtering the invalid KEY values in the entries, and avoids the impact on the processing performance of the chip. When the network is inspected, the content of the KEY is designed. For example, the most commonly used information in the TCP is the quintuple information. In the embodiment of the present invention, the useless content can be effectively filtered by the MASK to prevent the search result from being incorrect; for example, some entries are only If the IP address is not associated with the port number, the entry will be incorrectly searched. In the embodiment of the present invention, the content of the item that is not required to be considered in the entry may be filtered by the MASK according to the service involved in the entry, thereby avoiding the content that is not considered. Causes entries to be stored in multiple locations.

In other embodiments, before the step 100, the method of the embodiment of the present invention may further include the process shown in FIG. 3:

Step 300: Configure a third preset broom filter table;

In other embodiments, configuring the third preset Bloom filter table in the embodiment of the present invention includes:

Configuring a third preset Bloom filter table according to the number of entries supporting the conflict;

It should be noted that the number of entries supporting the conflict can be obtained by the simulation plus the margin after the maximum value is determined by simulation in the related art. The Bloom filter table of the embodiment of the present invention can be placed in on-chip static random access memory (SRAM).

Step 301: Perform CRC calculation on the KEY value of the entry to obtain a CRC result.

Step 302: Search all the Bloom filter tables using the CRC result to obtain a filter table result;

Step 303: Determine, according to the result of the filtering table, whether an entry exists.

Step 304: When it is determined that the entry exists, continue to check the table to determine that the entry does not exist, and stop checking the table.

In the embodiment of the present invention, by filtering the entries that do not exist, the occupation of the pin resources and the bandwidth resources is reduced, and the impact on the processing performance of the chip is avoided. Through the Bloom filter, it is judged whether the entry exists. If the entry does not exist, it is directly sent to the central processing unit (CPU) for processing, without wasting the subsequent look-up table bandwidth; the bloom fitter generally uses the on-chip static random access memory (SRAM). ,Static Random Access Memory) implementation;

In order to clarify the contents of the embodiments of the present invention, the following describes the bloom fitter:

The bloom fitter generally performs multiple CRC calculations, and performs a query of the bloom fitter table according to the results of multiple CRCs. Only the results of multiple CRCs are found to be 1 item of the bloom fitter result; therefore, multiple checks are required. Tables generally do not need to support continuous processing per cycle. You can use this type of processing; for example, when four cycles are processed, four CRC functions are used to calculate the CRC value to find the result of the bloom fitter table. Only after all hits, the subsequent processing is performed; otherwise, the processing is performed according to the miss condition; the bloom fitter table handles the hash (HASH) conflict, which may have multiple bits (bits), and multiple bits represent the number of collisions; A bloom fitter address supports 16 collisions, which requires 16 bits; at most, it takes 16 lookups to determine if an entry hits; if there is a rate requirement, then you cannot wait for a double rate synchronous dynamic random access memory to return. The next read, the worst case DDR read bandwidth will expand by 16 times, due to the high probability of HASH collision, DDR range bandwidth Swelling in more than two times, for the various types of DDR memory entry, the bandwidth expansion that is unacceptable.

It should be noted that the processing of steps 200-202 and the processing of steps 300-304 may be applied simultaneously in the embodiment of the present invention, or may be implemented as an embodiment separately. In the embodiment of the present invention, if the processing efficiency and precision are high, multiple sets of bloom fitter tables and multiple CRC functions can be used for processing, and only all the bloom fitters are hit for subsequent processing, otherwise, according to the loss (MISS). deal with;

It should be noted that, in the embodiment of the present invention, if the foregoing method for implementing table lookup processing is implemented in the form of a software function module, and is sold or used as a standalone product, it may also be stored in a computer readable storage medium. . Based on such understanding, the technical solution of the embodiments of the present invention may be embodied in the form of a software product in essence or in the form of a software product stored in a storage medium, including a plurality of instructions. One network device is caused to perform all or part of the method described in various embodiments of the present invention. The foregoing storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read only memory (ROM), a magnetic disk, or an optical disk. Thus, embodiments of the invention are not limited to any specific combination of hardware and software.

The embodiment of the invention further provides a computer storage medium, wherein the computer storage medium stores computer executable instructions, and the computer executable instructions are used to execute the method for implementing the table lookup processing.

An embodiment of the present invention further provides an apparatus for implementing a table lookup process, including: a memory and a processor; wherein

The processor is configured to execute program instructions in the memory;

Program instructions perform the following operations on the processor read:

The key (KEY) value of the entry is subjected to a first predetermined number of cyclic redundancy check (CRC) polynomial calculations;

Matching the result returned by the lookup table with the calculation result of other CRC polynomials other than the 0th CRC;

When the result returned by the look-up table matches the calculation result of other CRC polynomials, it is determined that the entry exists, and an off-chip hash HASH lookup table address is obtained according to the matching result;

When the off-chip hash table returns, the KEY value of the comparison entry is the same as the KEY value returned by the hash table. The KEY value of the entry is consistent with the KEY value returned by the hash table, and the entry is returned; the KEY value of the entry and the KEY value. The hash table returns an inconsistent KEY value, determining that the entry is missing.

The above description of the storage medium and device embodiments is similar to the description of the above method embodiments, and has similar advantageous effects as the method embodiments. For technical details not disclosed in the embodiments of the storage medium and device of the present invention, reference is made to the description of the method embodiments of the present invention.

4 is a structural block diagram of an apparatus for implementing a table lookup process according to an embodiment of the present invention. As shown in FIG. 4, the method includes: a first determining unit, a matching table address unit, a hash address unit, and a table lookup processing unit;

In other embodiments, the first determining unit is configured to:

In other embodiments, the lookup table processing unit is configured to: perform a lookup table according to the determined off-chip HASH lookup table address to obtain a hash check table to return a KEY value, and the KEY value of the entry and the hash check table return a KEY value, and return Entry; the KEY value of the entry does not match the hash checklist return KEY value, determining that the entry is missing.

In other embodiments, the lookup table processing unit is further configured to: send the entry to the central processing unit CPU when the result returned by the matching table lookup table does not match the calculation result of the other CRC polynomial except the 0th CRC Process it or process the item according to the preset rules.

The setting mask unit is configured to: set a second preset mask according to the entry related to the service setting;

The filtering unit is configured to: filter the invalid KEY value in the entry according to the selected MASK; wherein the packet parsing result includes the packet type.

In other embodiments, the apparatus further includes a configuration unit, a second calculation unit, a second lookup table unit, a second determination unit, and a second processing unit; wherein

The second lookup unit is configured to: find all Bloom filter tables using the CRC result, and obtain a filter table result;

The second processing unit is configured to: when it is determined that the entry exists, continue to look up the table, and determine that the entry does not exist, and stop checking the table.

In other embodiments, the configuration unit is configured to configure a third predetermined Bloom filter table based on the number of entries supporting the conflict.

The description of the above device embodiments is similar to the description of the above method embodiments, and has similar advantages as the method embodiments. For technical details not disclosed in the device embodiments of the present invention, please refer to the description of the method embodiments of the present invention.

The method of the present invention will be described in detail with reference to the application examples, which are only used to illustrate and explain the technical solutions of the present invention, and are not intended to limit the scope of the present invention.

FIG. 5 is a flowchart of a method for applying an example of the present invention. As shown in FIG. 5, the method includes:

Step 500, configuring a MASK value, a working mode, and related enabling, and the like;

Here, the operation mode, the related enablement, and the like can be set based on empirical values according to the art.

Step 501: Initialize a Bloom filter table content and match a table content;

Step 502: After the initialization is completed, receiving an externally input data including an entry;

Step 503: According to the type of the input data, select a corresponding MASK value, and perform bitwise operation on the KEY value of the data and the MASK to obtain a KEY value after the bit and the operation;

Step 504: Perform two or more CRC polynomial calculations in parallel with the KEY value obtained by the operation, and obtain four CRC calculation results;

Step 505, using four CRC values to respectively check the corresponding four Bloom filter tables;

Step 506, checking four Bloom filter tables to obtain return values of four Bloom filters;

Step 507: Determine a hit or a miss according to the return values of the four Bloom filters; wherein, when the return values of the four Bloom filters are all 1, the hit is indicated, and one of the return values of the four bloom fitters exists. If it is not 1, it means that it is missing; when it is not hit, step 516 is performed; when it is hit, step 508 is performed;

Step 508: Perform 8 polynomial calculations of different CRCs according to the KEY value, and obtain CRC calculation results calculated by 8 CRC polynomials;

Step 509: Query the matching table according to the calculation result of the 0th CRC, obtain 16 matching values, compare the first CRC with 16 matching value values, and output a 16-bit comparison result;

This embodiment outputs a total of 16*7bit results;

Step 510: Send, according to the 16-bit result, a final table lookup address calculated by seven CRC calculations;

Rule: If the first CRC matches, the position offset value is obtained according to the highest priority matching result; for example,

1. When the output comparison result is 0xffff, that is, all values match, 0 offset position is valid, and the final CRC1 lookup table output address is {CRC0, 4'd0};

2. When the output result is 0x0f**, the 4th bit of the highest priority match bit matches, the 4 offset position takes effect, and the final CRC1 lookup table output address is {CRC0, 4'd4};

3. When the output result is 0x0011, the highest priority match bit is matched by the 11th bit, and the 11 offset position is valid. The final CRC1 lookup table output address is {CRC0, 4'd11};

4. When the output result is 0x0002, the 14th bit of the highest priority match bit matches, and the 14 offset position takes effect; the final CRC1 lookup table output address is {CRC0, 4'd14;

In summary, in the embodiment of the present invention, the position of the first valid (1) is the offset value; the subsequent valid bits are not valid;

The results of CRC1 to CRC7 are the same. When CRC1 is valid, the result of the output of CRC1 is used, and so on. If all are invalid, the processing is performed in a miss manner.

Step 511: Obtain 7 results of CRC1 to CRC7;

Step 512, determining whether the results of the seven CRC1 to CRC7 are valid; when the results of the seven CRC1 to CRC7 are all valid, step 513; if there is a mismatch between the results of the seven CRC1 to CRC7, step 516;

Step 513: Select a corresponding CRC value according to the priority and the valid flag.

Step 514: Find a matching value table according to the selected CRC value, and obtain a matching value and a KEY value as a return value;

Step 515: Matching the KEY value of the entry with the KEY value returned by the read table, and determining whether the match is matched; if the KEY value of the entry matches the KEY value returned by the read table, step 517 is performed; if the KEY value of the entry is read The KEY value returned by the table does not match, and step 516 is performed;

Step 516: Perform processing according to a preset rule.

Step 517: processing according to the result returned by the reading table.

It is to be noted that FIG. 6 is a schematic diagram of a hardware entity of a device for performing table lookup processing according to an embodiment of the present invention. As shown in FIG. 6, the hardware entity of the device 600 includes: a processor 601, a communication interface 602, and a memory 603. ,among them

Processor 601 typically controls the overall operation of device 600.

Communication interface 602 can enable devices to communicate with other terminals or servers over a network.

The memory 603 is configured to store instructions and applications executable by the processor 601, and may also cache data to be processed or processed by the processor 601 and each module in the device 600, and may be flash memory (FLASH) or random access memory (Random Access). Memory, RAM) implementation.

It is to be understood that the phrase "one embodiment" or "an embodiment" or "an" Thus, "in one embodiment" or "in an embodiment" or "an" In addition, these particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It should be understood that, in various embodiments of the present invention, the size of the sequence numbers of the above processes does not mean the order of execution, and the order of execution of each process should be determined by its function and internal logic, and should not be taken to the embodiments of the present invention. The implementation process constitutes any limitation. The serial numbers of the embodiments of the present invention are merely for the description, and do not represent the advantages and disadvantages of the embodiments.

It is to be understood that the term "comprises", "comprising", or any other variants thereof, is intended to encompass a non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes those elements. It also includes other elements that are not explicitly listed, or elements that are inherent to such a process, method, article, or device. An element that is defined by the phrase "comprising a ..." does not exclude the presence of additional equivalent elements in the process, method, item, or device that comprises the element.

In the several embodiments provided by the present application, it should be understood that the disclosed apparatus and method may be implemented in other manners. The device embodiments described above are merely illustrative. For example, the division of the unit is only a logical function division. In actual implementation, there may be another division manner, such as: multiple units or components may be combined, or Can be integrated into another system, or some features can be ignored or not executed. In addition, the coupling, or direct coupling, or communication connection of the components shown or discussed may be indirect coupling or communication connection through some interfaces, devices or units, and may be electrical, mechanical or other forms. of.

The units described above as separate components may or may not be physically separated, and the components displayed as the unit may or may not be physical units; they may be located in one place or distributed on multiple network units; Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may be separately used as one unit, or two or more units may be integrated into one unit; The unit can be implemented in the form of hardware or in the form of hardware plus software functional units.

It will be understood by those skilled in the art that all or part of the steps of implementing the foregoing method embodiments may be performed by hardware related to program instructions. The foregoing program may be stored in a computer readable storage medium, and when executed, the program includes The foregoing steps of the method embodiment; and the foregoing storage medium includes: a removable storage device, a read only memory (ROM), a magnetic disk, or an optical disk, and the like, which can store program codes.

Alternatively, the above-described integrated unit of the present invention may be stored in a computer readable storage medium if it is implemented in the form of a software function module and sold or used as a standalone product. Based on such understanding, the technical solution of the embodiments of the present invention may be embodied in the form of a software product in essence or in the form of a software product stored in a storage medium, including a plurality of instructions. A network device (which may be a computing device, etc.) is caused to perform all or part of the methods described in various embodiments of the present invention. The foregoing storage medium includes various media that can store program codes, such as a mobile storage device, a ROM, a magnetic disk, or an optical disk.

The above is only the embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention. It is intended to be covered by the scope of the invention. Therefore, the scope of the invention should be determined by the scope of the appended claims.

Industrial applicability

In the embodiment of the present invention, according to the KEY value of the entry, the CRC polynomial calculation is used to determine whether the entry exists; when the entry is determined, the matching table address is determined according to the calculation result of the CRC polynomial; and the matching table is checked according to the determined matching table address. The returned result determines the off-chip HASH lookup table address; according to the determined off-chip HASH lookup table address, the hash table is returned to obtain the KEY value, and the KEY value according to the entry and the hash check table return whether the KEY value is consistent or not. Table processing; thus, the items that need to be looked up are reduced, the occupation of pin resources and bandwidth resources is reduced, and the impact on chip processing performance is avoided.

Claims

A method for implementing a table lookup process, which includes:

Determining whether an entry exists by a cyclic redundancy check CRC polynomial calculation according to the key KEY value of the entry;

When it is determined that the entry exists, the matching table address is determined according to the calculation result of the CRC polynomial;

Determining the off-chip hash HASH lookup table address according to the result of checking the matching table according to the determined matching table address;

According to the determined off-chip HASH lookup table address, the hash table is returned to obtain the KEY value, and the table is processed according to whether the KEY value of the entry and the hash table return the KEY value.
The method of claim 1 wherein said determining whether an entry exists comprises:

Performing the CRC polynomial calculation by using the KEY value of the entry for a first preset time;

Using the calculation result of the 0th CRC polynomial as the address of the matching table to perform a table lookup;

Matching the result returned by the matching table lookup table with the calculation result of other CRC polynomials other than the 0th CRC;

When the result returned by the matching table lookup table matches the calculation result of other CRC polynomials other than the 0th CRC, it is determined that the entry exists.
The method of claim 1, wherein the table lookup process according to whether the KEY value of the entry and the hash check table return a KEY value are consistent: the KEY value of the entry and the hash table return a KEY value Consistently, the entry is returned; the KEY value of the entry is inconsistent with the hash table return KEY value, and the entry is determined to be missed.
The method of claim 2, wherein the method further comprises:

If the result returned by the matching table lookup table does not match the calculation result of the other CRC polynomial except the 0th CRC, the entry is sent to the CPU of the central processing unit for processing, or the entry is based on Preset rules are processed.
The method according to any one of claims 1 to 4, wherein the method further comprises: before determining whether an entry exists by a cyclic redundancy check CRC polynomial calculation, the method further comprising:

Setting a second preset mask MASK according to the entry related to the service;

For each entry, select a corresponding type of MASK according to the packet parsing result, service step, and/or application mode;

Filter the invalid KEY value in the entry according to the selected MASK;

The packet parsing result includes a packet type.
The method according to any one of claims 1 to 4, wherein the method further comprises: before determining whether an entry exists by a cyclic redundancy check CRC polynomial calculation, the method further comprising:

Configuring a third preset Bloom filter table;

Performing a CRC calculation on the KEY value of the entry to obtain a CRC result;

Use the CRC result to find all Bloom filter tables to get the filter table results;

Determining whether the entry exists according to the result of the filtering table;

When it is determined that the entry exists, the table continues to be checked, and when it is determined that the entry does not exist, the table check is stopped.
The method of claim 6 wherein said configuring said third predetermined number of Bloom filter tables comprises:

The third predetermined one of the Bloom filter tables is configured according to the number of entries supporting the conflict.
An apparatus for implementing a table lookup process, comprising: a first determining unit, a matching table address unit, a hash address unit, and a table lookup processing unit; wherein

The first determining unit is configured to: determine, according to the key KEY value of the entry, whether the entry exists by using a cyclic redundancy check CRC polynomial calculation;

The matching table address unit is configured to: when determining the existence of the entry, determine the matching table address according to the calculation result of the CRC polynomial;

The hash address unit is configured to: determine an off-chip hash HASH lookup table address according to a result of performing a table lookup on the matching table according to the determined matching table address;

The lookup table processing unit is configured to: perform a lookup table according to the determined off-chip HASH lookup table address to obtain a hash check table to return a KEY value, and perform a table lookup according to whether the KEY value of the entry and the hash check table return a KEY value.
The apparatus of claim 8, wherein the first determining unit is configured to:

Performing the CRC polynomial calculation by using the KEY value of the entry for a first preset time;

Using the calculation result of the 0th CRC polynomial as the address of the matching table to perform a table lookup;

Matching the result returned by the matching table lookup table with the calculation result of other CRC polynomials other than the 0th CRC;

When the result returned by the matching table lookup table matches the calculation result of other CRC polynomials other than the 0th CRC, it is determined that the entry exists.
The apparatus of claim 8 wherein said lookup table processing unit is configured to:

Performing a lookup table according to the determined off-chip HASH lookup table address to obtain a hash table returning a KEY value, the KEY value of the entry is consistent with the return value of the hash table, and returning the entry; the KEY value of the entry And the hash table returns an inconsistency in the KEY value, determining that the entry misses.
The apparatus of claim 9, wherein the lookup table processing unit is further configured to:

If the result returned by the matching table lookup table does not match the calculation result of the other CRC polynomial except the 0th CRC, the entry is sent to the CPU of the central processing unit for processing, or the entry is based on Preset rules are processed.
The apparatus according to any one of claims 8 to 11, wherein the apparatus further comprises a setting mask unit, a mask selecting unit, and a filtering unit; wherein

Setting a mask unit is configured to: set a second preset mask MASK according to the entry related to the service;

The mask selection unit is configured to: select, for each entry, a corresponding type of MASK according to the packet parsing result, the service step, and/or the application mode;

The filtering unit is configured to: filter the invalid KEY value in the entry according to the selected MASK; wherein the packet parsing result includes the packet type.
The apparatus according to any one of claims 8 to 11, wherein the apparatus further comprises a configuration unit, a second calculation unit, a second lookup table unit, a second determination unit, and a second processing unit; wherein the configuration unit configuration To: configure a third preset Bloom filter table;

The second calculating unit is configured to perform a CRC calculation on the KEY value of the entry to obtain a CRC result;

The second look-up table unit is configured to: find all the Bloom filter tables by using the CRC result, and obtain a filter table result;

The second determining unit is configured to: determine, according to the result of the filtering table, whether the entry exists;

The second processing unit is configured to: when it is determined that the item exists, continue to look up the table, and determine that the item does not exist, stop searching the table.
The apparatus of claim 13 wherein said configuration unit is configured to:

The third predetermined one of the Bloom filter tables is configured according to the number of entries supporting the conflict.
An apparatus for performing a look-up table process, comprising a memory and a processor, the memory storing a computer program executable on a processor, the processor executing the program to implement any one of claims 1 to A step in a method of implementing a table lookup process.
A computer readable storage medium having stored thereon a computer program, the computer program being executed by a processor to implement the steps of a method for implementing table lookup processing according to any one of claims 1 to 7.