P4_learning——controller

控制器

通过控制器下发规则

拓扑

{
  "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"], ["s1", "s2"], ["s1", "s3"], ["s2", "s4"], ["s4", "s5"], ["s3", "s5"], ["s5", "h2"]],
    "hosts": {
      "h1": {
      },
      "h2": {
      }
    },
    "switches": {
      "s1": {
      },
      "s2": {
      },
      "s3": {
      },
      "s4": {
      },	
      "s5": {
      }	
    }
  }
}

p4文件

#include 
#include 
typedef bit<48> macAddr_t;
typedef bit<9> egressSpec_t;

header arp_t {
    bit<16> htype;
    bit<16> ptype;
    bit<8>  hlen;
    bit<8>  plen;
    bit<16> opcode;
    bit<48> hwSrcAddr;
    bit<32> protoSrcAddr;
    bit<48> hwDstAddr;
    bit<32> protoDstAddr;
}

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(".arp") 
    arp_t      arp;
    @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_arp") state parse_arp {
        packet.extract(hdr.arp);
        transition accept;
    }
    @name(".parse_ethernet") state parse_ethernet {
        packet.extract(hdr.ethernet);
        transition select(hdr.ethernet.etherType) {
            16w0x800: parse_ipv4;
            16w0x806: parse_arp;
            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 {
       if (hdr.ipv4.isValid()){
         ipv4_lpm.apply();
       }
    }
}

control DeparserImpl(packet_out packet, in headers hdr) {
    apply {
        packet.emit(hdr.ethernet);
        packet.emit(hdr.arp);
        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;

控制代码

from p4utils.utils.topology import Topology
from p4utils.utils.sswitch_API import SimpleSwitchAPI

class RoutingController(object):

    def __init__(self):

        self.topo = Topology(db="topology.db")
        self.controllers = {}
        self.init()

    def init(self):
        self.connect_to_switches()
        self.reset_states()
        self.set_table_defaults()

    def reset_states(self):
        [controller.reset_state() for controller in self.controllers.values()]

    def connect_to_switches(self):
        for p4switch in self.topo.get_p4switches():
            thrift_port = self.topo.get_thrift_port(p4switch)
            self.controllers[p4switch] = SimpleSwitchAPI(thrift_port)

    def set_table_defaults(self):
        for controller in self.controllers.values():
            controller.table_set_default("ipv4_lpm", "_drop", [])

    def route(self):

        switch_ecmp_groups = {sw_name:{} for sw_name in self.topo.get_p4switches().keys()}
	print "switch_ecmp_groups:", switch_ecmp_groups
        print "==============================================================================="
        print "self.controllers:", self.controllers
        print "==============================================================================="
        for sw_name, controller in self.controllers.items():
	   print sw_name, controller
           print "self.topo.get_hosts_connected_to(sw_name):", self.topo.get_hosts_connected_to(sw_name)
           for host in self.topo.get_hosts_connected_to(sw_name):
             sw_port = self.topo.node_to_node_port_num(sw_name, host)
             host_ip = self.topo.get_host_ip(host) + "/32"
             host_mac = self.topo.get_host_mac(host)
 	     print host, "(", host_ip, host_mac, ")", "-->", "sw_name with port:", sw_port  
        print "==============================================================================="
        #print "self.topo.get_p4switches:", self.topo.get_p4switches
        print "==============================================================================="
        for sw_dst in self.topo.get_p4switches(): 
           print "self.topo.get_hosts_connected_to(",sw_dst,"):", self.topo.get_hosts_connected_to(sw_dst)	    	
        print "==============================================================================="
	for sw_name, controller in self.controllers.items():
	   #print "sw_name:", sw_name, "controller:", controller
           for sw_dst in self.topo.get_p4switches():
              #print "sw_dst:", sw_dst
              # sw_name!=sw_dst and sw_dst with hosts situation
              if sw_name != sw_dst: 
 		if self.topo.get_hosts_connected_to(sw_dst):
                        #print "self.topo.get_hosts_connected_to(", sw_dst,"):", self.topo.get_hosts_connected_to(sw_dst)
                        paths = self.topo.get_shortest_paths_between_nodes(sw_name, sw_dst)
			print sw_name,"->",sw_dst,":",paths
			next_hops = [x[1] for x in paths]
			print "next_hops:", next_hops
                        for host in self.topo.get_hosts_connected_to(sw_dst):
                         #if len(paths) == 1:
			 #  next_hop = paths[0][1]
                         #  host_ip = self.topo.get_host_ip(host) + "/24"
                         #  sw_port = self.topo.node_to_node_port_num(sw_name, next_hop)
                         #  dst_sw_mac = self.topo.node_to_node_mac(next_hop, sw_name)  
                         #  print "next_hop:", next_hop, "host_ip:", host_ip, "sw_port:", sw_port, "dst_sw_mac:", dst_sw_mac
                         if len(paths) > 1:
                            #next_hops = [x[1] for x in paths]
  			    next_hop = paths[0][1]
                            host_ip = self.topo.get_host_ip(host) + "/24"	
 			    sw_port = self.topo.node_to_node_port_num(sw_name, next_hop)
			    dst_sw_mac = self.topo.node_to_node_mac(next_hop, sw_name) 	
                            print "next_hop:", next_hop, "host_ip:", host_ip, "sw_port:", sw_port, "dst_sw_mac:", dst_sw_mac  


        '''for sw_name, controller in self.controllers.items():
            for sw_dst in self.topo.get_p4switches():

                #if its ourselves we create direct connections
                if sw_name == sw_dst:
                    for host in self.topo.get_hosts_connected_to(sw_name):
                        sw_port = self.topo.node_to_node_port_num(sw_name, host)
                        host_ip = self.topo.get_host_ip(host) + "/32"
                        host_mac = self.topo.get_host_mac(host)

                        #add rule
                        print "table_add at {}:".format(sw_name)
                        self.controllers[sw_name].table_add("ipv4_lpm", "set_nhop", [str(host_ip)], [str(host_mac), str(sw_port)])

                #check if there are directly connected hosts
                else:
                    if self.topo.get_hosts_connected_to(sw_dst):
                        paths = self.topo.get_shortest_paths_between_nodes(sw_name, sw_dst)
                        for host in self.topo.get_hosts_connected_to(sw_dst):

                            if len(paths) == 1:
                                next_hop = paths[0][1]

                                host_ip = self.topo.get_host_ip(host) + "/24"
                                sw_port = self.topo.node_to_node_port_num(sw_name, next_hop)
                                dst_sw_mac = self.topo.node_to_node_mac(next_hop, sw_name)

                                #add rule
                                print "table_add at {}:".format(sw_name)
                                self.controllers[sw_name].table_add("ipv4_lpm", "set_nhop", [str(host_ip)],
                                                                    [str(dst_sw_mac), str(sw_port)])

                            elif len(paths) > 1:
                                next_hops = [x[1] for x in paths]
                                dst_macs_ports = [(self.topo.node_to_node_mac(next_hop, sw_name),
                                                   self.topo.node_to_node_port_num(sw_name, next_hop))
                                                  for next_hop in next_hops]
                                host_ip = self.topo.get_host_ip(host) + "/24"

                                #check if the ecmp group already exists. The ecmp group is defined by the number of next
                                #ports used, thus we can use dst_macs_ports as key
                                if switch_ecmp_groups[sw_name].get(tuple(dst_macs_ports), None):
                                    ecmp_group_id = switch_ecmp_groups[sw_name].get(tuple(dst_macs_ports), None)
                                    print "table_add at {}:".format(sw_name)
                                    self.controllers[sw_name].table_add("ipv4_lpm", "ecmp_group", [str(host_ip)],
                                                                        [str(ecmp_group_id), str(len(dst_macs_ports))])

                                #new ecmp group for this switch
                                else:
                                    new_ecmp_group_id = len(switch_ecmp_groups[sw_name]) + 1
                                    switch_ecmp_groups[sw_name][tuple(dst_macs_ports)] = new_ecmp_group_id

                                    #add group
                                    for i, (mac, port) in enumerate(dst_macs_ports):
                                        print "table_add at {}:".format(sw_name)
                                        self.controllers[sw_name].table_add("ecmp_group_to_nhop", "set_nhop",
                                                                            [str(new_ecmp_group_id), str(i)],
                                                                            [str(mac), str(port)])

                                    #add forwarding rule
                                    print "table_add at {}:".format(sw_name)
                                    self.controllers[sw_name].table_add("ipv4_lpm", "ecmp_group", [str(host_ip)],
                                                                        [str(new_ecmp_group_id), str(len(dst_macs_ports))])'''

    def main(self):
        self.route()


if __name__ == "__main__":
    controller = RoutingController().main()