birdagent.py

#!/usr/bin/python
#
# Copyright (c) 2016 Travelping GmbH <copyright@travelping.com>
# by Tobias Hintze <tobias.hintze@travelping.com>
#
# This code is inspired and partially copied from 
# https://r3blog.nl/index.php/archives/2011/02/24/bgp4-mib-support-for-bird/
# That original code does not clearly declare any license.
#
# This code also uses python-agentx library licensed under GPLv3
# (see agentx.py for details)
#
# So this code is licensed under the GPLv3 (see COPYING.GPLv3).
#

"""
birdagent - agentx code for the bird routing daemon
	used by bird_bgp - for the bgp4-mib
	used by bird_ospf - for the ospf-mib (not implemented)
"""

from adv_agentx import AgentX
from adv_agentx import SnmpGauge32,SnmpCounter32,SnmpIpAddress
import time,re,subprocess,glob

class BirdAgent:

	def __init__(self, cfgfile, birdcli, netstatcmd="netstat -na"):
		self.cfgfile = cfgfile
		self.birdcli = birdcli
		self.netstatcmd = netstatcmd

	bgp_states = {
		"idle":        1,
		"connect":     2,
		"active":      3,
		"opensent":    4,
		"openconfirm": 5,
		"established": 6,
	}

	_re_config_include = re.compile("^include\s*\"(/[^\"]*)\".*$")
	_re_config_bgp_proto_begin = re.compile("^protocol bgp ([a-zA-Z0-9_]+) .* \{$")
	_re_config_local_as = re.compile("local ([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+) as ([0-9]+);")
	_re_config_bgp_holdtime = re.compile("hold time ([0-9]+);")
	_re_config_bgp_keepalive = re.compile("keepalive time ([0-9]+);")
	_re_config_remote_peer = re.compile("neighbor ([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+) as ([0-9]+);")
	_re_config_timeformat = re.compile("\s*timeformat\s+protocol\s*\"%s\"\s*;")
	_re_config_proto_end = re.compile("^\}$")

	_re_birdcli_bgp_begin = re.compile("([a-zA-Z0-9_]+) *BGP * [a-zA-Z0-9_]+ * [a-zA-Z0-9]+ * ([a-zA-Z0-9:]+) *")
	_re_birdcli_bgp_peer = {
			"bgpPeerIdentifier": re.compile("Neighbor ID:.* ([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)"),
			"bgpPeerState": re.compile("BGP state:.* ([a-zA-Z]+)"),
			"bgpPeerLocalAddr": re.compile("Source address:.* ([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)"),
			"bgpPeerRemoteAddr": re.compile("Neighbor address:.* ([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)"),
			"bgpPeerRemoteAs": re.compile("Neighbor AS:.* ([0-9]+)"),
			"bgpPeerInUpdates": re.compile("Import updates:\ +([0-9]+) .*[0-9\-]+.*[0-9\-]+.*[0-9\-]+.*[0-9\-]+"),
			"bgpPeerOutUpdates": re.compile("Export updates:\ +([0-9]+) .*[0-9\-]+.*[0-9\-]+.*[0-9\-]+.*[0-9\-]+"),
			"bgpPeerHoldTime": re.compile("Hold timer:.* ([0-9]+)/[0-9]+"),
			"bgpPeerHoldTimeConfigured": re.compile("Hold timer:.* [0-9]+/([0-9]+)"),
			"bgpPeerKeepAlive": re.compile("Keepalive timer:.* ([0-9]+)/[0-9]+"),
			"bgpPeerKeepAliveConfigured": re.compile("Keepalive timer:.* [0-9]+/([0-9]+)"),
			"bgpPeerLastError": re.compile("Last error:\ +[a-zA-Z0-9-_\ ]+$")
			}
	_re_birdcli_bgp_end = re.compile("^$")

	_re_birdcli_ospf_neighbor = re.compile("^([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)\s+([0-9]+)\s+(\S+)\s+(\S+)\s+(\S+)\s+([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)")

	_re_netstat = re.compile("^tcp\s+[0-9]+\s+[0-9]+\s+([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+):([0-9]+)\s+([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+):([0-9]+)\s+ESTABLISHED")

	bgp_keys = [
			'bgpPeerIdentifier',
			'bgpPeerState',
			'bgpPeerAdminStatus',
			'bgpPeerNegotiatedVersion',
			'bgpPeerLocalAddr',
			'bgpPeerLocalPort',
			'bgpPeerRemoteAddr',
			'bgpPeerRemotePort',
			'bgpPeerRemoteAs',
			'bgpPeerInUpdates',
			'bgpPeerOutUpdates',
			'bgpPeerInTotalMessages',
			'bgpPeerOutTotalMessages',
			'bgpPeerLastError',
			'bgpPeerFsmEstablishedTransitions',
			'bgpPeerFsmEstablishedTime',
			'bgpPeerConnectRetryInterval',
			'bgpPeerHoldTime',
			'bgpPeerKeepAlive',
			'bgpPeerHoldTimeConfigured',
			'bgpPeerKeepAliveConfigured',
			'bgpPeerMinASOriginationInterval',
			'bgpPeerMinRouteAdvertisementInterval',
			'bgpPeerInUpdateElapsedTime',
			]


	bgp_defaults = {
			'bgpPeerIdentifier':                    SnmpIpAddress("0.0.0.0"),
			'bgpPeerLocalAddr':                     SnmpIpAddress("0.0.0.0"),
			'bgpPeerHoldTime':                      0,
			'bgpPeerHoldTimeConfigured':            0,
			'bgpPeerKeepAlive':                     0,
			'bgpPeerKeepAliveConfigured':           0,
			'bgpPeerState':                         1,
			'bgpPeerInUpdates':                     SnmpCounter32(0),
			'bgpPeerOutUpdates':                    SnmpCounter32(0),
			'bgpPeerAdminStatus':                   2,
			'bgpPeerConnectRetryInterval':          0,
			'bgpPeerFsmEstablishedTime':            SnmpGauge32(0),
			'bgpPeerFsmEstablishedTransitions':     SnmpCounter32(0),
			'bgpPeerInTotalMessages':               SnmpCounter32(0),
			'bgpPeerInUpdateElapsedTime':           SnmpGauge32(0),
			'bgpPeerLastError':                     '0',
			'bgpPeerMinASOriginationInterval':      15,
			'bgpPeerMinRouteAdvertisementInterval': 30,
			'bgpPeerNegotiatedVersion':             0,
			'bgpPeerOutTotalMessages':              SnmpCounter32(0),
			}


	@staticmethod
	def ipCompare(ip1, ip2):
		lst1 = "%3s.%3s.%3s.%3s" % tuple(ip1.split("."))
		lst2 = "%3s.%3s.%3s.%3s" % tuple(ip2.split("."))
		return cmp(lst1, lst2)

	@staticmethod
	def combinedConfigLines(filename):
		"""
		yield the whole bird configuration file line by line;
		all include-statements are resolved/unrolled
		"""
		with open(filename, "r") as bird_conf:
			for line in bird_conf:
				line = line.strip()
				match = BirdAgent._re_config_include.search(line)
				if not match:
					yield line
				else:
					for subconf in glob.glob(match.group(1)):
						yield "# subconf: %s (from %s)"%(subconf, line)
						for subline in BirdAgent.combinedConfigLines(subconf):
							yield subline

	@staticmethod
	def bgpKeys():
		return BirdAgent.bgp_keys

	def getOSPFState(self, ospf_instance):
		"""
		fetch OSPF-related state from:
		* parsing `birdc show ospf neighbors $ospf` output
		"""

		# "with"-context-manager for Popen not available in python < 3.2
		birdc = subprocess.Popen([self.birdcli, "show", "ospf", "neighbors", ospf_instance], \
				stdout=subprocess.PIPE)
		output = birdc.communicate()[0]
		if birdc.returncode != 0:
			print("ERROR: bird-CLI (querying ospf neighbors) %s failed: %i"%(self.birdcli, birdc.returncode))

		neighbors = {}
		for line in output.split("\n"):
			match = self._re_birdcli_ospf_neighbor.search(line)
			if match:
				rtrid, pri, state, deadtime, iface, rtrip = match.groups()
				neighbors[rtrid] = {}
				neighbors[rtrid]["pri"] = int(pri)
				neighbors[rtrid]["state"] = state
				neighbors[rtrid]["deadtime"] = deadtime
				neighbors[rtrid]["iface"] = iface
				neighbors[rtrid]["rtrip"] = rtrip
		return {"ospf-neighbors":neighbors}

	def getBGPState(self):
		"""
		fetch BGP-related state from:
		* parsing configuration file
		* parsing `birdc show protocols all` output
		* parsing `netstat` output
		"""

		current_time = int(time.time())

		# fetch some data from the configuration:
		cfg = {}
		cfg["bgp-peers"] = {}
		proto = None
		for line in BirdAgent.combinedConfigLines(self.cfgfile):
			if self._re_config_timeformat:
				cfg["timeformat"] = True
			match = self._re_config_bgp_proto_begin.search(line)
			if match:
				proto = match.group(1)
				cfg["bgp-peers"][proto] = {}
			if proto:
				match = self._re_config_local_as.search(line)
				if match:
					cfg["bgp-peers"][proto]["bgpPeerLocalAddr"] = SnmpIpAddress(match.group(1))
					cfg["bgp-peers"][proto]["bgpPeerLocalAs"] = int(match.group(2))
					if not cfg.has_key("bgpLocalAs"):
						cfg["bgpLocalAs"] = int(match.group(2))
					elif cfg["bgpLocalAs"] != int(match.group(2)):
						print("WARNING: multiple local AS: %i/%i"% \
								(cfg["bgpLocalAs"],int(match.group(2))))
				match = self._re_config_remote_peer.search(line)
				if match:
					cfg["bgp-peers"][proto]["bgpPeerRemoteAddr"] = SnmpIpAddress(match.group(1))
					cfg["bgp-peers"][proto]["bgpPeerRemoteAs"] = int(match.group(2))

				match = self._re_config_bgp_holdtime.search(line)
				if match:
					cfg["bgp-peers"][proto]["bgpPeerHoldTimeConfigured"] = int(match.group(1))

				match = self._re_config_bgp_keepalive.search(line)
				if match:
					cfg["bgp-peers"][proto]["bgpPeerKeepAliveConfigured"] = int(match.group(1))

			if self._re_config_proto_end.search(line):
				proto = None
		if not cfg.has_key("timeformat"):
			print("WARNING: timeformat not configured for this agent's use.")

		state = cfg.copy()
		bgp_proto = None
		ospf_proto = None
		# "with"-context-manager for Popen not available in python < 3.2
		birdc = subprocess.Popen([self.birdcli, "show", "protocols", "all"], \
				stdout=subprocess.PIPE)
		output = birdc.communicate()[0]
		if birdc.returncode != 0:
			print("ERROR: bird-CLI %s failed: %i"%(self.birdcli, birdc.returncode))
		for line in output.split("\n"):
			match = self._re_birdcli_bgp_begin.search(line)
			if match:
				bgp_proto = match.group(1)
				state["bgp-peers"][bgp_proto] = {}
				timestamp = int(match.group(2))
				if not state["bgp-peers"].has_key(bgp_proto):
					print("WARNING: proto \"%s\" not in config, skipping"%bgp_proto)
					continue
				state["bgp-peers"][bgp_proto]["bgpPeerFsmEstablishedTime"] = SnmpGauge32(current_time - timestamp)
			if bgp_proto:
				for peerprop_name, peerprop_re in self._re_birdcli_bgp_peer.items():
					match = peerprop_re.search(line)
					if match:
						if peerprop_name == 'bgpPeerState':
							state["bgp-peers"][bgp_proto][peerprop_name] = \
									self.bgp_states[match.group(1).lower()]
						elif peerprop_name in [
								'bgpPeerIdentifier',
								'bgpPeerLocalAddr',
								'bgpPeerRemoteAddr']:
							state["bgp-peers"][bgp_proto][peerprop_name] = SnmpIpAddress(match.group(1))
						elif peerprop_name in [
								'bgpPeerInUpdates', 
								'bgpPeerOutUpdates']:
							state["bgp-peers"][bgp_proto][peerprop_name] = SnmpCounter32(match.group(1))
						else:
							state["bgp-peers"][bgp_proto][peerprop_name] = int(match.group(1))
			if self._re_birdcli_bgp_end.search(line):
				bgp_proto = None

		# use netstat to query for tcp:179 connections
		bgp_sessions = {}
		netstat = subprocess.Popen( \
				"%s | grep '^tcp.*:179.*ESTABLISHED'"%self.netstatcmd,
				shell=True, stdout=subprocess.PIPE)
		for line in netstat.communicate()[0].split("\n"):
			match = self._re_netstat.search(line)
			if not match:
				continue
			# key 4-tuples by remote ip: src-addr, src-port, dst-addr, dst-port
			bgp_sessions[match.group(3)] = match.groups()

		# now match the tcp:179 4-tuples with bgp-state,
		# and enrich state by local+remote ports
		for proto in state["bgp-peers"].keys():
			state["bgp-peers"][proto]["bgpPeerLocalPort"] = 0
			state["bgp-peers"][proto]["bgpPeerRemotePort"] = 0
			if not bgp_sessions.has_key(state["bgp-peers"][proto]["bgpPeerRemoteAddr"]):
				# print("INFO: proto %s has no bgp session."%proto)
				continue
			srcip,srcport,dstip,dstport = bgp_sessions[state["bgp-peers"][proto]["bgpPeerRemoteAddr"]]
			if srcip != state["bgp-peers"][proto]["bgpPeerLocalAddr"] or \
					dstip != state["bgp-peers"][proto]["bgpPeerRemoteAddr"]:
				print("WARNING: proto %s has invalid BGP session (%s / %s)"%(proto, srcip, dstip))
				continue
			state["bgp-peers"][proto]["bgpPeerLocalPort"] = int(srcport)
			state["bgp-peers"][proto]["bgpPeerRemotePort"] = int(dstport)

		return state
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