20210517 Programming Protocol-independent Packet Processors ( P4 ) - 2

課堂資料

課堂練習

cd downloads

unzip 2.zip

cd 2

ls

gedit p4app.json basic.p4 cmd.txt

sed -i '/^$/d' p4app.json

p4run

h1 ping h2 -c 5

2 - 1

cp -r 2 2-1

cd 2-1

gedit p4app.json basic.p4 cmd.txt

cp cmd.txt cmd1.txt

cp cmd.txt cmd2.txt

ls

gedit p4app.json basic.p4 cmd1.txt cmd2.txt cmd3.txt

p4app.json

{
  "program": "basic.p4",
  "switch": "simple_switch",
  "compiler": "p4c",
  "options": "--target bmv2 --arch v1model --std p4-16",
  "switch_cli": "simple_switch_CLI",
  "cli": true,
  "pcap_dump": true,
  "enable_log": true,
  "topo_module": {
    "file_path": "",
    "module_name": "p4utils.mininetlib.apptopo",
    "object_name": "AppTopoStrategies"
  },
  "controller_module": null,
  "topodb_module": {
    "file_path": "",
    "module_name": "p4utils.utils.topology",
    "object_name": "Topology"
  },
  "mininet_module": {
    "file_path": "",
    "module_name": "p4utils.mininetlib.p4net",
    "object_name": "P4Mininet"
  },
  "topology": {
    "assignment_strategy":"l2",
    "links": [["h1", "s1"], ["h2", "s2"], ["h3", "s3"], ["s1", "s2"], ["s2", "s3"]],
    "hosts": {
      "h1": {
      },
      "h2": {
      },
      "h3": {
      }
    },
    "switches": {
      "s1": {
        "cli_input": "cmd.txt",
        "program": "basic.p4"
      },
      "s2": {
        "cli_input": "cmd2.txt",
        "program": "basic.p4"
      },
      "s3": {
        "cli_input": "cmd3.txt",
        "program": "basic.p4"
      }
    }
  }
}

cmd1.txt

table_add mac_forward forward 00:00:0a:00:00:01 => 1
table_add mac_forward forward 00:00:0a:00:00:02 => 2
table_add mac_forward forward 00:00:0a:00:00:03 => 2

cmd2.txt

table_add mac_forward forward 00:00:0a:00:00:01 => 2
table_add mac_forward forward 00:00:0a:00:00:02 => 1
table_add mac_forward forward 00:00:0a:00:00:03 => 3

cmd3.txt

table_add mac_forward forward 00:00:0a:00:00:01 => 2
table_add mac_forward forward 00:00:0a:00:00:02 => 2
table_add mac_forward forward 00:00:0a:00:00:03 => 1

3

cd p4-test/3

rm cmd.txt

gedit p4app.json ip_forward.p4 cmd.txt

p4app.json

 {
  "program": "ip_forward.p4",
  "switch": "simple_switch",
  "compiler": "p4c",
  "options": "--target bmv2 --arch v1model --std p4-16",
  "switch_cli": "simple_switch_CLI",
  "cli": true,
  "pcap_dump": true,
  "enable_log": true,
  "topo_module": {
    "file_path": "",
    "module_name": "p4utils.mininetlib.apptopo",
    "object_name": "AppTopoStrategies"
  },
  "controller_module": null,
  "topodb_module": {
    "file_path": "",
    "module_name": "p4utils.utils.topology",
    "object_name": "Topology"
  },
  "mininet_module": {
    "file_path": "",
    "module_name": "p4utils.mininetlib.p4net",
    "object_name": "P4Mininet"
  },
  "topology": {
    "assignment_strategy": "manual",
    "auto_arp_tables": "true",
    "auto_gw_arp": "true",
    "links": [["h1", "s1"], ["h2", "s1"]],
    "hosts": {
      "h1": {
        "ip": "10.0.1.1/24",
        "gw": "10.0.1.254"
      },
      "h2": {
        "ip": "10.0.2.1/24",
       "gw": "10.0.2.254"
      }
    },
    "switches": {
      "s1": {
        "cli_input": "cmd.txt",
        "program": "ip_forward.p4"
      }
    }
  }
}

ip_forward.p4

#include <core.p4>
#include <v1model.p4>
typedef bit<48> macAddr_t;
typedef bit<9> egressSpec_t;
  
header ethernet_t {
    bit<48> dstAddr;
    bit<48> srcAddr;
    bit<16> etherType;
}
 
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;
}
 
struct metadata {
}
 
struct headers {
    @name(".ethernet")
    ethernet_t ethernet;
    @name(".ipv4")
    ipv4_t     ipv4;
}
 
parser ParserImpl(packet_in packet, out headers hdr, inout metadata meta, inout standard_metadata_t standard_metadata) {
    @name(".parse_ethernet") state parse_ethernet {
        packet.extract(hdr.ethernet);
        transition select(hdr.ethernet.etherType) {
            16w0x800: parse_ipv4;
            default: accept;
        }
    }
    @name(".parse_ipv4") state parse_ipv4 {
        packet.extract(hdr.ipv4);
        transition accept;
    }
    @name(".start") state start {
        transition parse_ethernet;
    }
}
 
control egress(inout headers hdr, inout metadata meta, inout standard_metadata_t standard_metadata) {
    apply {
    }
}
 
control ingress(inout headers hdr, inout metadata meta, inout standard_metadata_t standard_metadata) {
    @name(".set_nhop") action set_nhop(macAddr_t dstAddr, egressSpec_t port) {
        //set the src mac address as the previous dst, this is not correct right?
        hdr.ethernet.srcAddr = hdr.ethernet.dstAddr;
 
        //set the destination mac address that we got from the match in the table
        hdr.ethernet.dstAddr = dstAddr;
 
        //set the output port that we also get from the table
        standard_metadata.egress_spec = port;
 
        //decrease ttl by 1
        hdr.ipv4.ttl = hdr.ipv4.ttl - 1;
    }
    @name("._drop") action _drop() {
        mark_to_drop(standard_metadata);
    }
    @name(".ipv4_lpm") table ipv4_lpm {
        actions = {
            set_nhop;
            _drop;
        }
        key = {
            hdr.ipv4.dstAddr: lpm;
        }
        size = 512;
        const default_action = _drop();
    }
    apply {
        ipv4_lpm.apply();
    }
}
 
control DeparserImpl(packet_out packet, in headers hdr) {
    apply {
        packet.emit(hdr.ethernet);
        packet.emit(hdr.ipv4);
    }
}
 
control verifyChecksum(inout headers hdr, inout metadata meta) {
    apply {
        verify_checksum(true, { 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);
    }
}
 
control computeChecksum(inout headers hdr, inout metadata meta) {
    apply {
        update_checksum(true, { 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);
    }
}
 
V1Switch(ParserImpl(), verifyChecksum(), ingress(), egress(), computeChecksum(), DeparserImpl()) main;

cmd.txt

table_add ipv4_lpm set_nhop 10.0.1.1/32 => 00:00:0a:00:01:01 1
table_add ipv4_lpm set_nhop 10.0.2.1/32 => 00:00:0a:00:02:01 2

exit

課堂作業

3 - 1

cp -r 3 3-1

cd 3-1

cp cmd.txt cmd1.txt

cp cmd.txt cmd2.txt

cp cmd.txt cmd3.txt

rm cmd.txt

gedit p4app.json ip_forward.p4 cmd1.txt cmd2.txt cmd3.txt

p4app.json

{
  "program": "ip_forward.p4",
  "switch": "simple_switch",
  "compiler": "p4c",
  "options": "--target bmv2 --arch v1model --std p4-16",
  "switch_cli": "simple_switch_CLI",
  "cli": true,
  "pcap_dump": true,
  "enable_log": true,
  "topo_module": {
    "file_path": "",
    "module_name": "p4utils.mininetlib.apptopo",
    "object_name": "AppTopoStrategies"
  },
  "controller_module": null,
  "topodb_module": {
    "file_path": "",
    "module_name": "p4utils.utils.topology",
    "object_name": "Topology"
  },
  "mininet_module": {
    "file_path": "",
    "module_name": "p4utils.mininetlib.p4net",
    "object_name": "P4Mininet"
  },
  "topology": {
    "assignment_strategy": "mixed",
    "auto_arp_tables": "true",
    "auto_gw_arp": "true",
    "links": [["h1", "s1"], ["h2", "s3"], ["h3", "s3"], ["s1", "s2"], ["s2", "s3"]],
    "hosts": {
      "h1": {
      },
      "h2": {
      },
      "h3": {
      }
    },
    "switches": {
      "s1": {
        "cli_input": "cmd1.txt",
        "program": "ip_forward.p4"
      },
      "s2": {
        "cli_input": "cmd2.txt",
        "program": "ip_forward.p4"
      },
      "s3": {
        "cli_input": "cmd3.txt",
        "program": "ip_forward.p4"
      }
    }
  }
}

cmd1.txt

table_add ipv4_lpm set_nhop 10.0.1.1/32 => 00:00:0a:00:01:01 1
table_add ipv4_lpm set_nhop 10.0.3.2/32 => 00:00:0a:00:03:02 2
table_add ipv4_lpm set_nhop 10.0.3.3/32 => 00:00:0a:00:03:03 2

cmd2.txt

table_add ipv4_lpm set_nhop 10.0.1.1/32 => 00:00:0a:00:01:01 1
table_add ipv4_lpm set_nhop 10.0.3.2/32 => 00:00:0a:00:03:02 2
table_add ipv4_lpm set_nhop 10.0.3.3/32 => 00:00:0a:00:03:03 2

cmd3.txt

table_add ipv4_lpm set_nhop 10.0.1.1/32 => 00:00:0a:00:01:01 3
table_add ipv4_lpm set_nhop 10.0.3.2/32 => 00:00:0a:00:03:02 1
table_add ipv4_lpm set_nhop 10.0.3.3/32 => 00:00:0a:00:03:03 2

cd ..

3 - 2

cp -r 3-1 3-2

cd 3-2

gedit p4app.json ip_forward.p4 cmd1.txt cmd2.txt cmd3.txt

p4app.json

{
  "program": "ip_forward.p4",
  "switch": "simple_switch",
  "compiler": "p4c",
  "options": "--target bmv2 --arch v1model --std p4-16",
  "switch_cli": "simple_switch_CLI",
  "cli": true,
  "pcap_dump": true,
  "enable_log": true,
  "topo_module": {
    "file_path": "",
    "module_name": "p4utils.mininetlib.apptopo",
    "object_name": "AppTopoStrategies"
  },
  "controller_module": null,
  "topodb_module": {
    "file_path": "",
    "module_name": "p4utils.utils.topology",
    "object_name": "Topology"
  },
  "mininet_module": {
    "file_path": "",
    "module_name": "p4utils.mininetlib.p4net",
    "object_name": "P4Mininet"
  },
  "topology": {
    "assignment_strategy": "l3",
    "auto_arp_tables": "true",
    "auto_gw_arp": "true",
    "links": [["h1", "s1"], ["h2", "s2"], ["h3", "s3"], ["s1", "s2"], ["s2", "s3"]],
    "hosts": {
      "h1": {
      },
      "h2": {
      },
      "h3": {
      }
    },
    "switches": {
      "s1": {
        "cli_input": "cmd1.txt",
        "program": "ip_forward.p4"
      },
      "s2": {
        "cli_input": "cmd2.txt",
        "program": "ip_forward.p4"
      },
      "s3": {
        "cli_input": "cmd3.txt",
        "program": "ip_forward.p4"
      }
    }
  }
}

cmd1.txt

table_add ipv4_lpm set_nhop 10.1.1.2/32 => 00:00:0a:01:01:02 1
table_add ipv4_lpm set_nhop 10.2.2.2/32 => 00:00:0a:02:02:02 2
table_add ipv4_lpm set_nhop 10.3.3.2/32 => 00:00:0a:03:03:02 2

cmd2.txt

table_add ipv4_lpm set_nhop 10.1.1.2/32 => 00:00:0a:01:01:02 2
table_add ipv4_lpm set_nhop 10.2.2.2/32 => 00:00:0a:02:02:02 1
table_add ipv4_lpm set_nhop 10.3.3.2/32 => 00:00:0a:03:03:02 3

cmd3.txt

table_add ipv4_lpm set_nhop 10.1.1.2/32 => 00:00:0a:01:01:02 2
table_add ipv4_lpm set_nhop 10.2.2.2/32 => 00:00:0a:02:02:02 2
table_add ipv4_lpm set_nhop 10.3.3.2/32 => 00:00:0a:03:03:02 1

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