topology_generator.py

import json
import argparse
import networkx


topo_base = {
  "p4_src": "p4src/traceroutable.p4",
  "cli": True,
  "pcap_dump": True,
  "enable_log": True,
  "topology": {
      "assignment_strategy": "l3"
  }
}

def create_linear_topo(num_switches):
    topo_base["topology"]["links"] = []

    #connect hosts with switches
    for i in range(1, num_switches+1):
        topo_base["topology"]["links"].append(["h{}".format(i), "s{0}".format(i)])

    #connect switches
    for i in range(1, num_switches):
        topo_base["topology"]["links"].append(["s{}".format(i), "s{}".format(i + 1)])

    topo_base["topology"]["hosts"] = {"h{0}".format(i): {} for i in range(1, num_switches + 1)}
    topo_base["topology"]["switches"] = {"s{0}".format(i): {} for i in range(1, num_switches + 1)}

def create_circular_topo(num_switches):

    create_linear_topo(num_switches)
    #add link between  s1 and sN
    topo_base["topology"]["links"].append(["s{}".format(1), "s{}".format(num_switches)])

def create_random_topo(degree=4, num_switches=10):

    topo_base["topology"]["links"] = []
    g = networkx.random_regular_graph(degree, num_switches)
    trials = 0
    while not networkx.is_connected(g):
        g = networkx.random_regular_graph(degree, num_switches)
        trials +=1
        if trials >= 10:
            print("Could not Create a connected graph")
            return

    # connect hosts with switches
    for i in range(1, num_switches + 1):
        topo_base["topology"]["links"].append(["h{}".format(i), "s{0}".format(i)])

    for edge in g.edges:
        topo_base["topology"]["links"].append(["s{}".format(edge[0]+1), "s{}".format(edge[1] + 1)])

    topo_base["topology"]["hosts"] = {"h{0}".format(i): {} for i in range(1, num_switches + 1)}
    topo_base["topology"]["switches"] = {"s{0}".format(i): {} for i in range(1, num_switches + 1)}


def main():
    pass

if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('--output_name', type=str, required=False, default="p4app_test.json")
    parser.add_argument("--topo", type=str, default="linear")
    parser.add_argument('-n', type=str, required=False, default=2)
    parser.add_argument('-d', type=str, required=False, default=4)
    args = parser.parse_args()

    if args.topo == "linear":
        create_linear_topo(int(args.n))
    elif args.topo == "circular":
        create_circular_topo(int(args.n))
    elif args.topo == "random":
        create_random_topo(int(args.d), int(args.n))

    json.dump(topo_base, open(args.output_name, "w"), sort_keys=True, indent=2)