Configuring a switch for extracting packet header fields

Abstract

A method for generating configuration data for configuring a hardware switch is described. The method receives a description of functionality for the hardware switch. Based on the description, the method generates sets of match and action entries to configure the hardware switch to process packets. The method then determines, for each packet header field in a parse graph that specifies instructions for a parser of the switch to extract packet header fields from packets, whether the packet header field is used or modified by at least one match or action entry. The method generates for the parser of the hardware switch configuration data that instructs the parser to extract (i) packet header fields used or modified by at least one match or action entry to a first set of registers and (ii) packet header fields not used by any match or action entries to a second set of registers.

1 - 20 . (canceled) 
     
     
         21 . An apparatus comprising:
 a forwarding element comprising:   circuitry to perform one or more match-action operations and   circuitry to provide one or more values that did not trigger performance of the one or more match-action operations or were not modified by one or more match-action operations by the circuitry to perform match-action operations.   
     
     
         22 . The apparatus of  claim 21 , wherein the one or more values comprise one or more packet header field values. 
     
     
         23 . The apparatus of  claim 21 , wherein the one or more values comprise one or more of: GENEVE variable length fields, multi-layer tunneling packet header data, or TCP packet header bytes. 
     
     
         24 . The apparatus of  claim 21 , comprising:
 circuitry to generate at least one packet that includes the one or more values and   circuitry to cause transmission of the at least one packet.   
     
     
         25 . The apparatus of  claim 21 , comprising:
 circuitry to provide one or more values that triggered performance of the one or more match-action operations or were modified by one or more match-action operations by the circuitry to perform match-action operations.   
     
     
         26 . The apparatus of  claim 23 , wherein the one or more values that triggered performance of the one or more match-action operations or were modified by one or more match-action operations by the circuitry to perform match-action operations comprise one or more packet header field values. 
     
     
         27 . The apparatus of  claim 21 , wherein the circuitry to provide one or more values that did not trigger performance of the one or more match-action operations or were not modified by one or more match-action operations by the circuitry to perform match-action operations is configured using P4 code. 
     
     
         28 . A non-transitory machine readable medium storing a program which when executed by at least one processing unit configures a packet processing pipeline of a hardware forwarding element, the program comprising sets of instructions to:
 configure a packet processing pipeline that performs match-action operations to:   provide one or more values that did not trigger performance of the one or more match-action operations or were not modified by one or more match-action operations by the circuitry to perform match-action operations.   
     
     
         29 . The non-transitory machine readable medium of  claim 28 , wherein the one or more values comprise one or more packet header field values. 
     
     
         30 . The non-transitory machine readable medium of  claim 28 , wherein the one or more values comprise one or more of: GENEVE variable length fields, multi-layer tunneling packet header data, or TCP packet header bytes. 
     
     
         31 . The non-transitory machine readable medium of  claim 28 , storing a program which when executed by at least one processing unit configures the packet processing pipeline of the hardware forwarding element, the program comprising sets of instructions to:
 configure the hardware forwarding element to:   generate at least one packet that includes the one or more values and   cause transmission of the at least one packet.   
     
     
         32 . The non-transitory machine readable medium of  claim 28 , storing a program which when executed by at least one processing unit configures the packet processing pipeline of the hardware forwarding element, the program comprising sets of instructions to:
 configure the packet processing pipeline that performs match-action operations to:   provide one or more values that triggered performance of the one or more match-action operations or were modified by one or more match-action operations by the circuitry to perform match-action operations.   
     
     
         33 . The non-transitory machine readable medium of  claim 32 , wherein the one or more values that triggered performance of the one or more match-action operations or were modified by one or more match-action operations by the circuitry to perform match-action operations comprise one or more packet header field values. 
     
     
         34 . The non-transitory machine readable medium of  claim 27 , wherein program comprises P4 code. 
     
     
         35 . A method comprising:
 in a packet processing pipeline of a forwarding element:   providing one or more values that did not trigger performance of one or more match-action operations or were not modified by one or more match-action operations.   
     
     
         36 . The method of  claim 35 , wherein the one or more values comprise one or more of: GENEVE variable length fields, multi-layer tunneling packet header data, or TCP packet header bytes. 
     
     
         37 . The method of  claim 35 , comprising:
 generating at least one packet that includes the one or more values and   causing transmission of the at least one packet.   
     
     
         38 . The method of  claim 35 , comprising:
 providing one or more values that triggered performance of the one or more match-action operations or were modified by one or more match-action operations.   
     
     
         39 . The method of  claim 38 , wherein the one or more values that triggered performance of the one or more match-action operations or were modified by one or more match-action operations comprise one or more packet header field values. 
     
     
         40 . The method of  claim 35 , wherein the providing one or more values that did not trigger performance of one or more match-action operations or were not modified by one or more match-action operations is based on a P4 program.