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added ternary match example
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‎examples/ternary_match/README.md‎

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# Ternary Match Example
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```
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+----+ +----+ +----+
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| h1 +-------+ s1 +---------+ h2 |
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+----+ +----+ +----+
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```
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# Introduction
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Very simple forwarding program that uses a ternary match. See `s1-commands.txt` to see
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how to populate tables with ternary matches using the CLI API. You will see that matches are
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of the form `value&mask`, for example: `0x00000000&&&0x80000000`, and the last action parameter
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is used as priority (lower better).
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# How to run
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To start the topology with the P4 switches:
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```
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sudo p4run
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```
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You can send packets and set different destination ip addresses to play with the program.
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```
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mx h1
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python send.py
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```

‎examples/ternary_match/p4app.json‎

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{
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"program": "ternary-match.p4",
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"switch": "simple_switch",
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"compiler": "p4c",
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"options": "--target bmv2 --arch v1model --std p4-16",
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"switch_cli": "simple_switch_CLI",
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"cli": true,
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"pcap_dump": true,
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"enable_log": true,
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"topo_module": {
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"file_path": "",
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"module_name": "p4utils.mininetlib.apptopo",
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"object_name": "AppTopo"
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},
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"controller_module": null,
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"topodb_module": {
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"file_path": "",
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"module_name": "p4utils.utils.topology",
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"object_name": "Topology"
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},
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"mininet_module": {
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"file_path": "",
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"module_name": "p4utils.mininetlib.p4net",
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"object_name": "P4Mininet"
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},
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"topology": {
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"assignment_strategy": "mixed",
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"links": [["h1", "s1"], ["h2", "s1"]],
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"hosts": {
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"h1": {
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},
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"h2": {
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}
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},
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"switches": {
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"s1": {
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"cli_input": "s1-commands.txt"
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}
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}
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}
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}

‎examples/ternary_match/run.sh‎

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#!/usr/bin/env bash
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#run
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P4APPRUNNER=p4run
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sudo $P4APPRUNNER "$@"

‎examples/ternary_match/s1-commands.txt‎

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table_set_default ternary_table drop
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table_add ternary_table ipv4_forward 0x00000000&&&0x80000000 => 00:00:00:00:00:01 2 5
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table_add ternary_table ipv4_forward 0x80000000&&&0x80000000 => 00:00:00:00:00:02 2 4
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table_add ternary_table ipv4_forward 0x80000000&&&0xc0000000 => 00:00:00:00:00:03 2 3
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table_add ternary_table ipv4_forward 0xe0000000&&&0xe0000000 => 00:00:00:00:00:04 2 2
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table_add ternary_table ipv4_forward 0xa0000000&&&0xe0000000 => 00:00:00:00:00:05 2 1

‎examples/ternary_match/send.py‎

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#!/usr/bin/env python
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import sys
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import socket
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import random
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from subprocess import Popen, PIPE
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import re
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from scapy.all import sendp, get_if_list, get_if_hwaddr
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from scapy.all import Ether, IP, UDP, TCP
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def get_if():
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ifs=get_if_list()
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iface=None # "h1-eth0"
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for i in get_if_list():
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if "eth0" in i:
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iface=i
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break;
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if not iface:
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print "Cannot find eth0 interface"
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exit(1)
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return iface
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def get_dst_mac(ip):
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try:
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pid = Popen(["arp", "-n", ip], stdout=PIPE)
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s = pid.communicate()[0]
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mac = re.search(r"(([a-f\d]{1,2}\:){5}[a-f\d]{1,2})", s).groups()[0]
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return mac
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except:
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return None
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def main():
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if len(sys.argv)<3:
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print 'pass 2 arguments: <destination> "<message>"'
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exit(1)
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addr = socket.gethostbyname(sys.argv[1])
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iface = get_if()
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if len(sys.argv) > 3:
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tos = int(sys.argv[3]) % 256
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else:
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tos = 0
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#ether_dst = get_dst_mac(addr)
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print "Sending on interface %s to %s" % (iface, str(addr))
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pkt = Ether(src=get_if_hwaddr(iface), dst="01:01:01:01:01:01")
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pkt = pkt /IP(dst=addr,tos=tos) / sys.argv[2]
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sendp(pkt, iface=iface, verbose=False)
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if __name__ == '__main__':
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main()

‎examples/ternary_match/ternary-match.p4‎

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/* -*- P4_16 -*- */
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#include <core.p4>
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#include <v1model.p4>
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const bit<16> TYPE_IPV4 = 0x800;
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/*************************************************************************
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*********************** H E A D E R S ***********************************
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*************************************************************************/
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typedef bit<9> egressSpec_t;
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typedef bit<48> macAddr_t;
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typedef bit<32> ip4Addr_t;
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header ethernet_t {
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macAddr_t dstAddr;
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macAddr_t srcAddr;
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bit<16> etherType;
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}
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header ipv4_t {
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bit<4> version;
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bit<4> ihl;
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bit<8> diffserv;
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bit<16> totalLen;
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bit<16> identification;
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bit<3> flags;
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bit<13> fragOffset;
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bit<8> ttl;
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bit<8> protocol;
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bit<16> hdrChecksum;
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ip4Addr_t srcAddr;
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ip4Addr_t dstAddr;
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}
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struct metadata {
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/* empty */
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}
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struct headers {
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ethernet_t ethernet;
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ipv4_t ipv4;
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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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TYPE_IPV4: ipv4;
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default: accept;
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}
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}
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state ipv4 {
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packet.extract(hdr.ipv4);
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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, 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 drop() {
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mark_to_drop(standard_metadata);
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}
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action ipv4_forward(macAddr_t dstAddr, egressSpec_t port) {
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//set the src mac address as the previous dst, this is not correct right?
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hdr.ethernet.srcAddr = hdr.ethernet.dstAddr;
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//set the destination mac address that we got from the match in the table
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hdr.ethernet.dstAddr = dstAddr;
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//set the output port that we also get from the table
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standard_metadata.egress_spec = port;
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//decrease ttl by 1
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hdr.ipv4.ttl = hdr.ipv4.ttl -1;
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}
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table ternary_table {
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key = {
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hdr.ipv4.dstAddr: ternary;
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}
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actions = {
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ipv4_forward;
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drop;
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NoAction;
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}
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size = 1024;
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default_action = NoAction();
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}
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apply {
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//only if IPV4 the rule is applied. Therefore other packets will not be forwarded.
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if (hdr.ipv4.isValid()){
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ternary_table.apply();
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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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update_checksum(
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hdr.ipv4.isValid(),
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{ hdr.ipv4.version,
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hdr.ipv4.ihl,
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hdr.ipv4.diffserv,
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hdr.ipv4.totalLen,
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hdr.ipv4.identification,
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hdr.ipv4.flags,
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hdr.ipv4.fragOffset,
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hdr.ipv4.ttl,
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hdr.ipv4.protocol,
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hdr.ipv4.srcAddr,
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hdr.ipv4.dstAddr },
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hdr.ipv4.hdrChecksum,
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HashAlgorithm.csum16);
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}
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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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//parsed headers have to be added again into the packet.
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packet.emit(hdr.ethernet);
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packet.emit(hdr.ipv4);
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}
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}
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/*************************************************************************
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*********************** S W I T C H *******************************
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*************************************************************************/
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//switch architecture
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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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