WO2012075818A1

WO2012075818A1 - Method for parsing packet header, header parsing pre-processing device and network processor

Info

Publication number: WO2012075818A1
Application number: PCT/CN2011/077916
Authority: WO
Inventors: 冷星星; 钱勇
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-12-10
Filing date: 2011-08-02
Publication date: 2012-06-14
Also published as: CN102014065A

Abstract

The present invention provides a method for parsing a packet header, a header parsing pre-processing device and a network processor. The method comprises: when the number of header types of a packet exceeds nine, analyzing a header of the packet, and re-defining a repetitive header type as a new header type; and adding a new parsing rule according to the new header type, and parsing a header type of the packet according to the new parsing rule. Through the present invention, a repetitive header type is re-defined as a new header type, a new parsing rule is added according to the new header type, and a header type of the packet is parsed according to the new parsing rule, so that in an original system, without increasing the hardware cost, an effective header type can still be parsed as required, and is provided to be used by a microcode.

Description

Packet header parsing method, packet header parsing preprocessor, and network processor

Technical field

The present invention relates to communication technologies, and in particular, to a packet header parsing method, a packet header parsing preprocessing apparatus, and a network processor.

Background technique

The Ternary Content Address Memory (TCAM) is a content-based query-based memory that has the advantages of fast query speed and fixed query time. There are several entries pre-stored in the TCAM, and each entry corresponds to a rule; in the static random access memory (SRAM), a specific action (Action) corresponding to the entry in the TCAM is prestored. When the packet is classified, the packet is matched with the TCAM entry. If an entry matches the packet successfully, the packet is stored in the SRAM corresponding to the TCAM entry. Actions, thereby achieving the purpose of classifying messages. The content of each bit in the TCAM entry has three forms, namely 0, 1, and *, where 0 and 1 represent specific binary digits, and * indicates that the bit does not participate in the comparison, that is, when matching is performed, the bit The default match is successful.

In some network processors, the packet header parsing preprocessing module based on the above two types of storage units mainly performs rule matching on the packet header and parses out the header type inside, such as Ethernet (ethernet) medium access control (Mac). Ethernet type (etype), virtual local area network (WLAN), multi-protocol label switching (MPLS) label, etc. This part of the information is carried to the subsequent network processor in a fixed format through an additional field-one header parsing field. Code usage. According to this fixed format, the microcode takes out the valid information and the type of the packet header. For example, if it is a Layer 2 packet, the second layer process is performed, and the mac is searched for the mac address. For the third layer, the ip address is taken for routing. Find. The existence of the header parsing field makes the operation of the microcode simple and effective. In order to ensure the bandwidth and processing efficiency of the network processor, the header parsing field usually has a fixed format and length limit, so the number of header types that need to be parsed is limited.

As shown in FIG. 1 , it is a schematic structural diagram of an existing network processor, where the network processor includes a packet header preprocessing module, a table lookup processing module, and a package forwarding module. A packet is generally processed by the packet header parsing, table lookup, and encapsulation and forwarding in the network processor. A Layer 3 packet is used as an example to describe the process of processing the packet by the network processor. The process includes: The packet header parsing pre-processing module first matches the packet as a Layer 3 packet, and performs some pre-processing: Legality check, ip header checksum (checksum) and calculations, etc.

The lookup table processing module mainly performs classification processing on the parsed packets: the Layer 3 packets go to the Layer 3 process, and the destination ip checks the routing forwarding table;

The encapsulation and forwarding module performs packet update encapsulation according to the result of the lookup table. For example, the Layer 3 packet needs to be updated with mac and vlan, and the egress information is forwarded according to the lookup table.

In the network processor, the packet header parsing preprocessing module is a microcode independent module, and the parsing result is transmitted to a subsequent microcode processing (including table lookup processing and encapsulation and forwarding) unit through a predetermined format. This can greatly simplify microcode processing; however, at the same time, in order to ensure the bandwidth and processing efficiency of the network processor, the information that is passed to the microcode processing, including the parsed header type, is often limited.

As shown in FIG. 2, a schematic diagram of the working principle of the preprocessing module of the existing packet header parsing, the packet header parsing preprocessing module includes a rule matching module and an execution module, and the rule matching module is composed of a TCAM unit, which mainly completes the rule matching of the packet header; The module is composed of SRAM units, which mainly performs related operations on the header of the matching rule, for example, filling the header type into the header parsing field.

The following describes the working process of the module:

1. Initialization of the module: Fill in the matching rule of the header type A_B_C_D_E_D_G to the i-th entry in the TCAM; fill in the corresponding operation in the SRAM - sequentially parse the seven types in the header;

2. Message matching: At this time, if a message matching the i rule is entered, the related operations in the SRAM will be executed: Fill the header types A, B, C, D, E, D, G into the header parsing field respectively. And according to the parsed message type, go to the corresponding processing flow for microcode processing.

It can be seen that the number of valid header types parsed by the network processor is generally nine, which can satisfy the analysis of the current majority of the packets, and does not waste hardware resources, and the bandwidth and processing of the network processor. effectiveness. However, under certain special functions, the effective type of the header that needs to be parsed may exceed the limit of nine, and the current technical solution cannot solve the problem. Summary of the invention

In order to solve the above technical problem, the present invention provides a packet header parsing method, a packet header parsing preprocessing apparatus, and a network processor, so as to implement an effective system in the original system without increasing the hardware cost. Header type, for microcode use.

The present invention provides a method for parsing a packet header, the method comprising:

When the number of packet header types exceeds 9, the header of the packet is analyzed, and the duplicate header type is redefined as a new header type;

A new parsing rule is added according to the new packet header type, and the packet header type of the packet is parsed according to the new parsing rule.

The method further includes: when the number of the packet header types of the packet does not exceed nine, parsing the header type of the text in turn.

The steps to add a new parsing rule based on the new header type include: Adding a new parsing rule to the Triple Content Addressable Register (TCAM) based on the new header type.

The method further includes: after parsing the packet header type of the packet according to the new parsing rule, performing microcode processing on the parsed header type.

The present invention also provides a packet header parsing preprocessing apparatus, the packet header parsing preprocessing apparatus comprising: a redefining module, configured to: when the number of packet header types exceeds 9, analyze the "3⁄4 text" The header, and redefines the repeated header type to a new header type; and a parsing module, which is set to: add a new parsing rule according to the new header type, and parse the packet header according to the new parsing rule Types of.

The packet header pre-processing apparatus further includes: a packet header parsing module configured to parse the packet header type of the packet in sequence when the number of packet header types of the packet does not exceed nine.

The parsing module is arranged to add a new parsing rule by: adding the new parsing rule to a triple content addressable register (TCAM) according to a new header type.

The present invention also provides a network processor, which includes a packet header parsing preprocessing module, a table lookup processing module, and a package forwarding module, where:

The packet header parsing pre-processing module is configured to: when the number of packet header types exceeds 9, Parsing the header of the "3⁄4 text", and redefining the repeated header type as a new header type; and, adding a new parsing rule according to the new header type, parsing the packet according to the new parsing rule The header type of the packet is sent to the table lookup processing module; the lookup table processing module is configured to perform classification processing according to the header type of the parsed message; the package forwarding module is set according to The result of the classification processing of the table lookup processing module is to update and encapsulate the message.

The packet header pre-processing module is further configured to: when the number of packet header types does not exceed 9, the packet header type of the packet is parsed in turn, and the parsed header type of the parsed packet is sent to the lookup table. Processing module.

The header parsing pre-processing module is arranged to add a new parsing rule by adding the new parsing rule to a triple content addressable register (TCAM) according to a new header type.

The parsing method of the packet header, the header parsing preprocessing apparatus and the network processor re-define the repeated header type into a new header type, add a new parsing rule according to the new header type, and parse according to the new parsing rule. The type of packet header of the message; so that under the original system, without increasing the hardware cost, the valid header type can still be parsed according to the requirements for use by the microcode. BRIEF abstract

1 is a schematic structural diagram of a conventional network processor;

2 is a schematic diagram showing the principle of the work of the existing packet header parsing preprocessing module;

3 is a flowchart of a method for matching a message rule according to the present invention;

4 is a schematic structural diagram of a packet header parsing preprocessing apparatus according to the present invention;

FIG. 5 is a schematic structural diagram of a network processor according to the present invention. Preferred embodiment of the invention

The technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. In practical applications, there may be more than 9 valid header types for some messages, and the longest effective header type in the application reaches 12. If the hardware structure is changed for these limited message types, the system cost is increased, which is too costly.

The present invention provides a parsing method for a packet header, which can parse a header type for efficient use of the microcode, the method comprising:

The parsing method of the packet header may further include: when the number of the packet header types does not exceed nine, the packet header type of the packet is parsed in turn according to the prior art.

If there is a need to process a message of the following type, there are 10 types of header types that need to be parsed: A—B—C—D—D—D—G—H—I—J, and its processing is shown in Figure 3. :

Step 301: Determine whether the current number of packet header types exceeds 9, for the packet parsing rule that does not exceed 9 types, step 302 is performed, and if there are more than 9, the step 303 is performed;

Step 302, sequentially parsing each packet header type in sequence; Go to step 306;

Step 303: In the case that the type of the packet header exceeds 9, the header of the packet is analyzed, and some of the header types are newly defined as a new header type, so that the header type of the new rule can be controlled to be 9 Within the scope;

Several types of headers defined as new header types are mainly based on the convenience of microcode processing. Generally, several headers with relatively few microcode operations are merged. Here, three repetitive D types are redefined as a triple. D (tripleD) type;

Step 304: Re-add a matching rule according to the new type definition;

The matching rule is the parsing rule, that is, the driver adds a new parsing rule to the TCAM: A B C tripleD G H I J;

Step 305: The message matches the new rule, and the new packet header type is parsed.

At the same time, the corresponding operations are filled in the SRAM - the header types A, B, C, tripleD are parsed in turn. G, H, I, J;

Step 306: The message parsing is completed, and the corresponding microcode processing flow is entered.

Microcode only needs to add the relevant operations for the new header type without affecting the entire process.

When there are more than 9 valid header types to be parsed, the header type contained in it contains a duplicate header type; these repeated multiple header types can be redefined as a header type. In this way, the packet header parsing pre-processing module can perform all types of parsing without excessively increasing the micro-code processing complexity, so that the packet header parsing module can expand the function without expanding the hardware resources.

As shown in FIG. 4, it is a schematic structural diagram of a packet header parsing preprocessing apparatus according to the present invention. The header parsing preprocessing apparatus includes a redefining module 41 and a parsing module 42, wherein the redefining module is configured to: when the number of header types exceeds 9 At the same time, the packet header is analyzed, and the repeated header type is redefined as a new header type; the parsing module is set to: add a new parsing rule according to the new header type, and parse according to the new parsing rule The header type of the message.

In addition, the packet header pre-processing apparatus further includes a packet header parsing module configured to: when the number of packet header types does not exceed nine, parse the packet header type according to the procedure shown in FIG. 2.

The parsing module may be configured to add a new parsing rule to the TCAM according to the new header type.

The packet header pre-processing device can parse the packet header type of the packet, and the implementation process is the same as that of the packet header. For details, refer to FIG. 3.

The packet header parsing preprocessing apparatus re-defines the repeated header type into a new header type by the redefinition module, adds a new parsing rule according to the new header type by the parsing module, and parses the packet according to the new parsing rule. The header type; so that under the original system, without increasing the hardware cost, the valid header type can still be parsed according to the requirements for microcode use.

As shown in FIG. 5, it is a schematic structural diagram of a network processor according to the present invention. The network processor includes a packet header parsing preprocessing module 51, a table lookup processing module 52, and a packet forwarding module 53, wherein: the packet header parsing preprocessing module is configured to : When the number of packet header types exceeds 9, The header of the message, and redefines the repeated header type to a new header type; and, according to the new header type, adds a new parsing rule, parses the packet header type according to the new parsing rule, and The packet header type of the parsed packet is sent to the table lookup processing module; the lookup table processing module is configured to perform classification processing according to the parsed header type of the parsed packet; and the encapsulation and forwarding module is configured to perform classification processing according to the table lookup processing module. Update the encapsulation of the message.

Preferably, the packet header pre-processing module is further configured to: when the number of packet header types does not exceed 9, the packet header type of the packet is parsed in turn, and the header type of the parsed packet is sent to the lookup table. Processing module. The header parsing pre-processing module is the same as the header parsing pre-processing apparatus, and is not described here.

Further, the packet header parsing pre-processing module may add the new parsing rule to a triple content addressable register (TCAM) according to a new header type.

The network processor, by combining some of the header types, enables the packet header preprocessing module to effectively parse the type information required for microcode processing, while ensuring that the microcode does not use too many instructions in processing. , thereby improving the operating efficiency of the entire system.

One of ordinary skill in the art will appreciate that all or a portion of the above steps may be accomplished by a program that instructs the associated hardware to be stored in a computer readable storage medium, such as a read only memory, a magnetic disk, or an optical disk. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the above embodiment may be implemented in the form of hardware or in the form of a software function module. The invention is not limited to any specific form of combination of hardware and software.

The above embodiments are only intended to illustrate the technical solutions of the present invention and are not to be construed as limiting the invention. It should be understood by those skilled in the art that the present invention may be modified or equivalently substituted without departing from the spirit and scope of the invention.

Industrial applicability

Compared with the prior art, the present invention re-defines the repeated header type into a new header type, adds a new parsing rule according to the new header type, and parses the packet according to the new parsing rule. The type of the header is such that, under the original system, without increasing the hardware cost, the effective header type can still be solved as required for the microcode.

Claims

Claim

1. A parsing method for a packet header, the method comprising:

2. The method for parsing a packet header according to claim 1, further comprising:

When the number of the packet header types of the packet does not exceed nine, the packet header type of the packet is parsed in turn.

The method for parsing a packet header according to claim 1 or 2, wherein the step of adding a new parsing rule according to the new header type comprises:

Add a new parsing rule to the Triple Content Addressable Register (TCAM) based on the new header type.

The method for parsing a packet header according to claim 1 or 2, further comprising: after parsing the packet header type of the packet according to the new parsing rule,

Microcode processing is performed on the parsed header type.

5. A packet header parsing preprocessing apparatus, comprising:

Redefining the module, which is set to: when the number of packet header types exceeds 9, analyze the "3⁄4 text header", and redefine the repeated header type to a new header type; and the parsing module, It is set to: add a new parsing rule according to the new packet header type, and parse the packet header type of the packet according to the new parsing rule.

6. The packet header preprocessing apparatus according to claim 5, further comprising:

The packet header parsing module is configured to: when the number of packet header types of the packet does not exceed nine, parse the packet header type of the packet in turn.

7. The packet header analysis preprocessing apparatus according to claim 5 or 6, wherein

8. A network processor, the network processor comprising a packet header parsing preprocessing module, a table lookup processing module, and a package forwarding module, wherein:

The packet header parsing pre-processing module is configured to: when the number of packet header types exceeds 9, analyze the "3⁄4 text header", and redefine the repeated header type into a new header type; and, Adding a new parsing rule according to the new packet header type, parsing the packet header type of the packet according to the new parsing rule, and sending the parsed header type of the parsed packet to the table lookup processing module;

The lookup table processing module is configured to perform classification processing according to the packet header type of the parsed packet; the encapsulation and forwarding module is configured to perform packet update encapsulation according to the classification processing result of the table lookup processing module.

9. The network processor according to claim 8, wherein

The packet header pre-processing module is further configured to: when the number of packet header types of the packet does not exceed nine, parse the header type of the text in turn, and parse the parsed header type of the text Send to the table lookup processing module.

10. The network processor according to claim 8 or 9, wherein