load_balance_advanced.p4

// This file is part of the Planter extend project: QCMP.
// This program is a free software tool, which does ensemble in-network reinforcement learning for load balancing.
// licensed under Apache-2.0
// Copyright (c) 2022-2023 Benjamin Rienecker Modified by Changgang Zheng
// Copyright (c) Computing Infrastructure Group, Department of Engineering Science, University of Oxford

/* -*- P4_16 -*- */
#include <core.p4>
#include <v1model.p4>

const bit<5>  IPV4_OPTION_MRI = 31;
const bit<16> TYPE_IPV4 = 0x800;
const bit<16> TYPE_SRCROUTING = 0x1234;

#define MAX_HOPS 9

/*************************************************************************
*********************** H E A D E R S  ***********************************
*************************************************************************/

typedef bit<32> switchID_t;
typedef bit<32> qdepth_t;

header ethernet_t {
    bit<48> dstAddr;
    bit<48> srcAddr;
    bit<16> etherType;
}

header srcRoute_t {
    bit<1>    bos;
    bit<15>   port;
}

header ipv4_t {
    bit<4>  version;
    bit<4>  ihl;
    bit<8>  diffserv;
    bit<16> totalLen;
    bit<16> identification;
    bit<3>  flags;
    bit<13> fragOffset;
    bit<8>  ttl;
    bit<8>  protocol;
    bit<16> hdrChecksum;
    bit<32> srcAddr;
    bit<32> dstAddr;
}

header ipv4_option_t {
    bit<1> copyFlag;
    bit<2> optClass;
    bit<5> option;
    bit<8> optionLength;
}

header mri_t {
    bit<16>  count;
}

header switch_t {
    switchID_t  swid;
    qdepth_t    qdepth;
}

header tcp_t {
    bit<16> srcPort;
    bit<16> dstPort;
    bit<32> seqNo;
    bit<32> ackNo;
    bit<4>  dataOffset;
    bit<3>  res;
    bit<3>  ecn;
    bit<6>  ctrl;
    bit<16> window;
    bit<16> checksum;
    bit<16> urgentPtr;
}

struct metadata {
    bit<14>  ecmp_select;
    bit<16>  count;
    bit<16>  remaining;
}

struct headers {
    ethernet_t              ethernet;
    srcRoute_t[MAX_HOPS]    srcRoutes;
    ipv4_t                  ipv4;
    ipv4_option_t           ipv4_option;
    mri_t                   mri;
    switch_t[MAX_HOPS]      swtraces;
    tcp_t                   tcp;
}

error { IPHeaderTooShort }

/*************************************************************************
*********************** P A R S E R  ***********************************
*************************************************************************/

parser MyParser(packet_in packet,
                out headers hdr,
                inout metadata meta,
                inout standard_metadata_t standard_metadata) {

    state start {
        transition parse_ethernet;
    }
    state parse_ethernet {
        packet.extract(hdr.ethernet);
        transition select(hdr.ethernet.etherType) {
            TYPE_IPV4: parse_ipv4;
            TYPE_SRCROUTING: parse_srcRouting;
            default: accept;
        }
    }

    state parse_srcRouting {
        packet.extract(hdr.srcRoutes.next);
        transition select(hdr.srcRoutes.last.bos) {
            1: parse_ipv4;
            default: parse_srcRouting;
        }
    }

    state parse_ipv4 {
        packet.extract(hdr.ipv4);
        verify(hdr.ipv4.ihl >= 5, error.IPHeaderTooShort);
        transition select(hdr.ipv4.ihl) {
            5             : parse_tcp;
            default       : parse_ipv4_option;
        }
    }

    state parse_ipv4_option {
        packet.extract(hdr.ipv4_option);
        transition select(hdr.ipv4_option.option) {
            IPV4_OPTION_MRI: parse_mri;
            default: accept;
        }
    }

  state parse_mri {
      packet.extract(hdr.mri);
      meta.remaining = hdr.mri.count;
      transition select(meta.remaining) {
          0 : parse_tcp;
          default: parse_swtrace;
      }
  }

  state parse_swtrace {
      packet.extract(hdr.swtraces.next);
      meta.remaining = meta.remaining  - 1;
      transition select(meta.remaining) {
          0 : parse_tcp;
          default: parse_swtrace;
      }
  }

  state parse_tcp {
        packet.extract(hdr.tcp);
        transition accept;
    }
}

/*************************************************************************
************   C H E C K S U M    V E R I F I C A T I O N   *************
*************************************************************************/

control MyVerifyChecksum(inout headers hdr, inout metadata meta) {
    apply { }
}

/*************************************************************************
**************  I N G R E S S   P R O C E S S I N G   *******************
*************************************************************************/

control MyIngress(inout headers hdr,
                  inout metadata meta,
                  inout standard_metadata_t standard_metadata) {
    action drop() {
        mark_to_drop(standard_metadata);
    }

    action srcRoute_nhop() {
        standard_metadata.egress_spec = (bit<9>)hdr.srcRoutes[0].port;
        hdr.srcRoutes.pop_front(1);
    }

    action srcRoute_finish() {
        hdr.ethernet.etherType = TYPE_IPV4;
    }

    action update_ttl(){
        hdr.ipv4.ttl = hdr.ipv4.ttl - 1;
    }

    action set_ecmp_select(bit<32> ecmp_count) {
        hash(meta.ecmp_select,
            HashAlgorithm.crc16,
            (bit<1>)0,
            { hdr.ipv4.srcAddr,
              hdr.ipv4.dstAddr,
              hdr.ipv4.protocol,
              hdr.tcp.srcPort,
              hdr.tcp.dstPort },
            ecmp_count);
    }

    action set_nhop(bit<48> nhop_dmac, bit<32> nhop_ipv4, bit<9> port) {
        hdr.ethernet.dstAddr = nhop_dmac;
        hdr.ipv4.dstAddr = nhop_ipv4;
        standard_metadata.egress_spec = port;
        hdr.ipv4.ttl = hdr.ipv4.ttl - 1;
    }

    table ecmp_group {
        key = {
            hdr.ipv4.dstAddr: lpm;
        }
        actions = {
            drop;
            set_ecmp_select;
        }
        size = 1024;
    }

    table ecmp_nhop {
        key = {
            meta.ecmp_select: exact;
        }
        actions = {
            drop;
            set_nhop;
        }
        size = 100;
    }

    apply {
        if (hdr.srcRoutes[0].isValid()){
            if (hdr.srcRoutes[0].bos == 1){
                srcRoute_finish();
            }
            srcRoute_nhop();
            if (hdr.ipv4.isValid()){
                update_ttl();
            }
        } else if (hdr.ipv4.isValid() && hdr.ipv4.ttl > 0 && hdr.mri.isValid()) {
            ecmp_group.apply();
            ecmp_nhop.apply();
        }
    }
}

/*************************************************************************
****************  E G R E S S   P R O C E S S I N G   *******************
*************************************************************************/

control MyEgress(inout headers hdr,
                 inout metadata meta,
                 inout standard_metadata_t standard_metadata) {

    action rewrite_mac(bit<48> smac) {
        hdr.ethernet.srcAddr = smac;
    }

    action drop() {
        mark_to_drop(standard_metadata);
    }

    action add_swtrace(switchID_t swid) {
        hdr.mri.count = hdr.mri.count + 1;
        hdr.swtraces.push_front(1);
        // According to the P4_16 spec, pushed elements are invalid, so we need
        // to call setValid(). Older bmv2 versions would mark the new header(s)
        // valid automatically (P4_14 behavior), but starting with version 1.11,
        // bmv2 conforms with the P4_16 spec.
        hdr.swtraces[0].setValid();
        hdr.swtraces[0].swid = swid;
        hdr.swtraces[0].qdepth = (qdepth_t)standard_metadata.deq_qdepth;

        hdr.ipv4.ihl = hdr.ipv4.ihl + 2;
        hdr.ipv4_option.optionLength = hdr.ipv4_option.optionLength + 8;
        hdr.ipv4.totalLen = hdr.ipv4.totalLen + 8;
    }

    table send_frame {
        key = {
            standard_metadata.egress_port: exact;
        }
        actions = {
            rewrite_mac;
            drop;
        }
        size = 256;
    }

    table swtrace {
        actions = {
            add_swtrace;
            NoAction;
        }
        default_action = NoAction();
    }

    apply {
        if (hdr.mri.isValid()) {
            swtrace.apply();
        }
        send_frame.apply();
    }
}

/*************************************************************************
*************   C H E C K S U M    C O M P U T A T I O N   **************
*************************************************************************/

control MyComputeChecksum(inout headers hdr, inout metadata meta) {
     apply {
        update_checksum(
            hdr.ipv4.isValid(),
            { hdr.ipv4.version,
              hdr.ipv4.ihl,
              hdr.ipv4.diffserv,
              hdr.ipv4.totalLen,
              hdr.ipv4.identification,
              hdr.ipv4.flags,
              hdr.ipv4.fragOffset,
              hdr.ipv4.ttl,
              hdr.ipv4.protocol,
              hdr.ipv4.srcAddr,
              hdr.ipv4.dstAddr },
            hdr.ipv4.hdrChecksum,
            HashAlgorithm.csum16);
    }
}

/*************************************************************************
***********************  D E P A R S E R  *******************************
*************************************************************************/

control MyDeparser(packet_out packet, in headers hdr) {
    apply {
        packet.emit(hdr.ethernet);
        packet.emit(hdr.srcRoutes);
        packet.emit(hdr.ipv4);
        packet.emit(hdr.ipv4_option);
        packet.emit(hdr.mri);
        packet.emit(hdr.swtraces);
        packet.emit(hdr.tcp);
    }
}

/*************************************************************************
***********************  S W I T C H  *******************************
*************************************************************************/

V1Switch(
MyParser(),
MyVerifyChecksum(),
MyIngress(),
MyEgress(),
MyComputeChecksum(),
MyDeparser()
) main;