#!/usr/bin/env python3 import argparse import enum import select import socket import subprocess import sys import time from argparse import ArgumentDefaultsHelpFormatter from functools import cmp_to_key from queue import Queue from threading import Thread from typing import Dict, Tuple import grpc from core import utils from core.api.grpc.client import CoreGrpcClient from core.api.grpc.wrappers import NodeType SDT_HOST = "127.0.0.1" SDT_PORT = 50000 ROUTE_LAYER = "CORE Route" DEAD_TIME = 3 ROUTE_TIME = 3 PACKET_CHOICES = ["udp", "tcp", "icmp"] class RouteEnum(enum.Enum): ADD = 0 DEL = 1 class SdtClient: def __init__(self, address: Tuple[str, int]) -> None: self.sock = socket.create_connection(address) self.links = [] self.send(f'layer "{ROUTE_LAYER}"') def close(self) -> None: self.sock.close() def send(self, cmd: str) -> None: sdt_cmd = f"{cmd}\n".encode() self.sock.sendall(sdt_cmd) def add_link(self, node1, node2) -> None: route_id = f"{node1}-{node2}-r" link_id = f"{node1},{node2},{route_id}" cmd = f'link {link_id} linkLayer "{ROUTE_LAYER}" line yellow,2' self.send(cmd) self.links.append(link_id) def delete_links(self) -> None: for link_id in self.links: cmd = f"delete link,{link_id}" self.send(cmd) self.links.clear() class RouterMonitor: def __init__( self, session: int, src: str, dst: str, pkt: str, rate: int, dead: int, sdt_host: str, sdt_port: int, ) -> None: self.queue = Queue() self.core = CoreGrpcClient() self.session = session self.src_id = None self.src = src self.dst = dst self.pkt = pkt self.rate = rate self.dead = dead self.seen = {} self.running = False self.route_time = None self.listeners = [] self.sdt = SdtClient((sdt_host, sdt_port)) self.nodes = self.get_nodes() def get_nodes(self) -> Dict[int, str]: with self.core.context_connect(): if self.session is None: self.session = self.get_session() print("session: ", self.session) try: session = self.core.get_session(self.session) node_map = {} for node in session.nodes.values(): if node.type != NodeType.DEFAULT: continue node_map[node.id] = node.channel if self.src_id is None: _, ifaces, _ = self.core.get_node(self.session, node.id) for iface in ifaces: if self.src == iface.ip4: self.src_id = node.id break except grpc.RpcError: print(f"invalid session: {self.session}") sys.exit(1) if self.src_id is None: print(f"could not find node with source address: {self.src}") sys.exit(1) print( f"monitoring src_id ({self.src_id}) src({self.src}) dst({self.dst}) pkt({self.pkt})" ) return node_map def get_session(self) -> int: sessions = self.core.get_sessions() session = None if sessions: session = sessions[0] if not session: print("no current core sessions") sys.exit(1) return session.id def start(self) -> None: self.running = True for node_id, node in self.nodes.items(): print("listening on node: ", node) thread = Thread(target=self.listen, args=(node_id, node), daemon=True) thread.start() self.listeners.append(thread) self.manage() def manage(self) -> None: self.route_time = time.monotonic() while self.running: route_enum, node, seen = self.queue.get() if route_enum == RouteEnum.ADD: self.seen[node] = seen elif node in self.seen: del self.seen[node] if (time.monotonic() - self.route_time) >= self.rate: self.manage_routes() self.route_time = time.monotonic() def route_sort(self, x: Tuple[str, int], y: Tuple[str, int]) -> int: x_node = x[0] y_node = y[0] if x_node == self.src_id: return 1 if y_node == self.src_id: return -1 x_ttl, y_ttl = x[1], y[1] return x_ttl - y_ttl def manage_routes(self) -> None: self.sdt.delete_links() if not self.seen: return values = sorted( self.seen.items(), key=cmp_to_key(self.route_sort), reverse=True ) print("current route:") for index, node_data in enumerate(values): next_index = index + 1 if next_index == len(values): break next_node_id = values[next_index][0] node_id, ttl = node_data print(f"{node_id} -> {next_node_id}") self.sdt.add_link(node_id, next_node_id) def stop(self) -> None: self.running = False self.sdt.delete_links() self.sdt.close() for thread in self.listeners: thread.join() self.listeners.clear() def listen(self, node_id, node) -> None: cmd = f"tcpdump -lnvi any src host {self.src} and dst host {self.dst} and {self.pkt}" node_cmd = f"vcmd -c {node} -- {cmd}" p = subprocess.Popen( node_cmd, shell=True, stdout=subprocess.PIPE, stderr=subprocess.DEVNULL ) current = time.monotonic() try: while not p.poll() and self.running: ready, _, _ = select.select([p.stdout], [], [], 1) if ready: line = p.stdout.readline().strip().decode() if line: line = line.split("ttl", 1)[1] ttl = int(line.split(",", 1)[0]) p.stdout.readline() self.queue.put((RouteEnum.ADD, node_id, ttl)) current = time.monotonic() else: if (time.monotonic() - current) >= self.dead: self.queue.put((RouteEnum.DEL, node_id, None)) except Exception as e: print(f"listener error: {e}") def main() -> None: if not utils.which("tcpdump", required=False): print("core-route-monitor requires tcpdump to be installed") return desc = "core route monitor leverages tcpdump to monitor traffic and find route using TTL" parser = argparse.ArgumentParser( description=desc, formatter_class=ArgumentDefaultsHelpFormatter ) parser.add_argument( "--src", required=True, help="source address for route monitoring" ) parser.add_argument( "--dst", required=True, help="destination address for route monitoring" ) parser.add_argument("--session", type=int, help="session to monitor route") parser.add_argument( "--pkt", default="icmp", choices=PACKET_CHOICES, help="packet type" ) parser.add_argument( "--rate", type=int, default=ROUTE_TIME, help="rate to update route, in seconds" ) parser.add_argument( "--dead", type=int, default=DEAD_TIME, help="timeout to declare path dead, in seconds", ) parser.add_argument("--sdt-host", default=SDT_HOST, help="sdt host address") parser.add_argument("--sdt-port", type=int, default=SDT_PORT, help="sdt port") args = parser.parse_args() monitor = RouterMonitor( args.session, args.src, args.dst, args.pkt, args.rate, args.dead, args.sdt_host, args.sdt_port, ) try: monitor.start() except KeyboardInterrupt: monitor.stop() print("ending route monitor") if __name__ == "__main__": main()