bird.py

# coding: utf-8

class Route:
	def __init__(self, network):
		self.network = network

class BGPRoute(Route):
	def __init__(self, network, origin="IGP", as_path=[], next_hop=None,
			community=[], med=0):
		Route.__init__(self, network)
		self.origin = origin
		self.as_path = as_path
		self.next_hop = next_hop
		self.community = community
		self.med = med

	def as_path_pairs(self):
		pairs = []
		i = 0
		while i < len(self.as_path) - 1:
			pair = (self.as_path[i], self.as_path[i + 1])
			if pair not in pairs and pair[0] != pair[1]:
				pairs.append(pair)
			i += 1
		return pairs

class Parser:
	def __init__(self, static_route=Route, bgp_route=BGPRoute):
		self.static_route = static_route
		self.bgp_route = bgp_route
		pass

	def parse_route_body(self, network, route_body):
		raw_routes = []
		c_route = None
		for key, value in map(lambda x: x.split(": "), route_body):
			if key == "Type":
				if c_route:
					raw_routes.append(c_route)
					c_route = None
				c_route = {}
			c_route[key] = value
		if c_route:
			raw_routes.append(c_route)

		routes = []
		for route in raw_routes:
			if route["Type"].split(" ")[0] == "BGP":
				new_route = self.bgp_route(
					network,
					origin=route.get("BGP.origin"),
					as_path=route.get("BGP.as_path").split(" "),
					next_hop=route.get("BGP.next_hop"),
					med=route.get("BGP.med"),
				)
				if "BGP.community" in route:
					new_route.community = list(map(lambda x: (x[0], x[1]), map(lambda x: x[1:-1].split(","), route.get("BGP.community", "").split(" "))))

			else:
				new_route = self.static_route(network)
			
			routes.append(new_route)

		return routes

	def parse_routes(self, routes):
		network = None
		networks = {}
		for line in routes.split("\n"):
			if len(line) == 0:
				continue
			if line[0] == "\t":
				networks[network].append(line[1:])
			elif line[0:8] == " " * 8:
				networks[network][-1] += "\n" + line.replace(" " * 8, "\t")
			else:
				network = line.split("  ")[0]
				networks[network] = []

		routes = []
		for network, route_body in networks.items():
			routes += self.parse_route_body(network, route_body)

		return routes