Created new subdirectory for Fall developer day. (#60)
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Robert Soule
GitHub
256
P4D2_2017_Fall/exercises/calc/solution/calc.p4
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256
P4D2_2017_Fall/exercises/calc/solution/calc.p4
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/* -*- P4_16 -*- */
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/*
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* P4 Calculator
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*
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* This program implements a simple protocol. It can be carried over Ethernet
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* (Ethertype 0x1234).
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*
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* The Protocol header looks like this:
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*
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* 0 1 2 3
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* +----------------+----------------+----------------+---------------+
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* | P | 4 | Version | Op |
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* +----------------+----------------+----------------+---------------+
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* | Operand A |
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* +----------------+----------------+----------------+---------------+
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* | Operand B |
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* +----------------+----------------+----------------+---------------+
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* | Result |
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* +----------------+----------------+----------------+---------------+
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*
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* P is an ASCII Letter 'P' (0x50)
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* 4 is an ASCII Letter '4' (0x34)
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* Version is currently 0.1 (0x01)
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* Op is an operation to Perform:
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* '+' (0x2b) Result = OperandA + OperandB
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* '-' (0x2d) Result = OperandA - OperandB
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* '&' (0x26) Result = OperandA & OperandB
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* '|' (0x7c) Result = OperandA | OperandB
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* '^' (0x5e) Result = OperandA ^ OperandB
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*
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* The device receives a packet, performs the requested operation, fills in the
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* result and sends the packet back out of the same port it came in on, while
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* swapping the source and destination addresses.
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*
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* If an unknown operation is specified or the header is not valid, the packet
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* is dropped
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*/
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#include <core.p4>
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#include <v1model.p4>
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/*
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* Define the headers the program will recognize
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*/
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/*
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* Standard ethernet header
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*/
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header ethernet_t {
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bit<48> dstAddr;
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bit<48> srcAddr;
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bit<16> etherType;
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}
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/*
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* This is a custom protocol header for the calculator. We'll use
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* ethertype 0x1234 for is (see parser)
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*/
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const bit<16> P4CALC_ETYPE = 0x1234;
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const bit<8> P4CALC_P = 0x50; // 'P'
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const bit<8> P4CALC_4 = 0x34; // '4'
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const bit<8> P4CALC_VER = 0x01; // v0.1
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const bit<8> P4CALC_PLUS = 0x2b; // '+'
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const bit<8> P4CALC_MINUS = 0x2d; // '-'
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const bit<8> P4CALC_AND = 0x26; // '&'
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const bit<8> P4CALC_OR = 0x7c; // '|'
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const bit<8> P4CALC_CARET = 0x5e; // '^'
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header p4calc_t {
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bit<8> p;
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bit<8> four;
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bit<8> ver;
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bit<8> op;
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bit<32> operand_a;
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bit<32> operand_b;
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bit<32> res;
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}
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/*
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* All headers, used in the program needs to be assembed into a single struct.
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* We only need to declare the type, but there is no need to instantiate it,
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* because it is done "by the architecture", i.e. outside of P4 functions
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*/
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struct headers {
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ethernet_t ethernet;
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p4calc_t p4calc;
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}
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/*
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* All metadata, globally used in the program, also needs to be assembed
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* into a single struct. As in the case of the headers, we only need to
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* declare the type, but there is no need to instantiate it,
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* because it is done "by the architecture", i.e. outside of P4 functions
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*/
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struct metadata {
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/* In our case it is empty */
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}
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/*************************************************************************
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*********************** P A R S E R ***********************************
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*************************************************************************/
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parser MyParser(packet_in packet,
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out headers hdr,
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inout metadata meta,
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inout standard_metadata_t standard_metadata) {
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state start {
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packet.extract(hdr.ethernet);
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transition select(hdr.ethernet.etherType) {
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P4CALC_ETYPE : check_p4calc;
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default : accept;
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}
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}
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state check_p4calc {
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transition select(packet.lookahead<p4calc_t>().p,
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packet.lookahead<p4calc_t>().four,
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packet.lookahead<p4calc_t>().ver) {
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(P4CALC_P, P4CALC_4, P4CALC_VER) : parse_p4calc;
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default : accept;
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}
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}
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state parse_p4calc {
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packet.extract(hdr.p4calc);
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transition accept;
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}
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}
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/*************************************************************************
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************ C H E C K S U M V E R I F I C A T I O N *************
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*************************************************************************/
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control MyVerifyChecksum(inout headers hdr,
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inout metadata meta) {
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apply { }
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}
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/*************************************************************************
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************** I N G R E S S P R O C E S S I N G *******************
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*************************************************************************/
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control MyIngress(inout headers hdr,
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inout metadata meta,
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inout standard_metadata_t standard_metadata) {
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action send_back(bit<32> result) {
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bit<48> tmp;
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/* Put the result back in */
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hdr.p4calc.res = result;
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/* Swap the MAC addresses */
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tmp = hdr.ethernet.dstAddr;
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hdr.ethernet.dstAddr = hdr.ethernet.srcAddr;
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hdr.ethernet.srcAddr = tmp;
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/* Send the packet back to the port it came from */
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standard_metadata.egress_spec = standard_metadata.ingress_port;
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}
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action operation_add() {
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send_back(hdr.p4calc.operand_a + hdr.p4calc.operand_b);
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}
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action operation_sub() {
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send_back(hdr.p4calc.operand_a - hdr.p4calc.operand_b);
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}
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action operation_and() {
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send_back(hdr.p4calc.operand_a & hdr.p4calc.operand_b);
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}
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action operation_or() {
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send_back(hdr.p4calc.operand_a | hdr.p4calc.operand_b);
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}
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action operation_xor() {
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send_back(hdr.p4calc.operand_a ^ hdr.p4calc.operand_b);
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}
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action operation_drop() {
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mark_to_drop();
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}
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table calculate {
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key = {
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hdr.p4calc.op : exact;
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}
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actions = {
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operation_add;
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operation_sub;
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operation_and;
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operation_or;
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operation_xor;
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operation_drop;
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}
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const default_action = operation_drop();
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const entries = {
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P4CALC_PLUS : operation_add();
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P4CALC_MINUS: operation_sub();
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P4CALC_AND : operation_and();
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P4CALC_OR : operation_or();
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P4CALC_CARET: operation_xor();
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}
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}
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apply {
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if (hdr.p4calc.isValid()) {
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calculate.apply();
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} else {
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operation_drop();
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}
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}
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}
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/*************************************************************************
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**************** E G R E S S P R O C E S S I N G *******************
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*************************************************************************/
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control MyEgress(inout headers hdr,
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inout metadata meta,
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inout standard_metadata_t standard_metadata) {
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apply { }
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}
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/*************************************************************************
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************* C H E C K S U M C O M P U T A T I O N **************
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*************************************************************************/
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control MyComputeChecksum(inout headers hdr, inout metadata meta) {
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apply { }
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}
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/*************************************************************************
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*********************** D E P A R S E R *******************************
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*************************************************************************/
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control MyDeparser(packet_out packet, in headers hdr) {
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apply {
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packet.emit(hdr.ethernet);
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packet.emit(hdr.p4calc);
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}
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}
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/*************************************************************************
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*********************** S W I T T C H **********************************
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*************************************************************************/
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V1Switch(
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MyParser(),
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MyVerifyChecksum(),
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MyIngress(),
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MyEgress(),
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MyComputeChecksum(),
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MyDeparser()
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) main;
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