"""Routing Information Protocol."""

from pypacker import pypacker, triggerlist

import logging

logger = logging.getLogger("pypacker")

# RIP v2 - RFC 2453
# http://tools.ietf.org/html/rfc2453

REQUEST		= 1
RESPONSE	= 2


class RIP(pypacker.Packet):
	__hdr__ = (
		("cmd", "B", REQUEST),
		("v", "B", 2),
		("rsvd", "H", 0),
		("rte_auth", None, triggerlist.TriggerList)
	)

	def _dissect(self, buf):
		self._init_triggerlist("rte_auth", buf[4:], self.__parse_auths)
		return len(buf)

	def __parse_auths(self, buf):
		off = 0
		auths = []

		while off + 20 <= len(buf):
			if buf[off: off + 2] == b"\xff\xff":
				auth_rte = Auth(buf[off: off + 20])
			else:
				auth_rte = RTE(buf[off: off + 20])
			# logger.debug("RIP: adding auth/rte: %s" % auth_rte)
			auths.append(auth_rte)
			off += 20
		return auths


class RTE(pypacker.Packet):
	__hdr__ = (
		("family", "H", 2),
		("route_tag", "H", 0),
		("addr", "I", 0),
		("subnet", "I", 0),
		("next_hop", "I", 0),
		("metric", "I", 1)
	)


class Auth(pypacker.Packet):
	__hdr__ = (
		("rsvd", "H", 0xFFFF),
		("type", "H", 2),
		("auth", "16s", b"\x00" * 16)
	)