routerbox/utils/he_ipv6/tunnelbroker.py

import datetime
import json
import logging
import os
import socket
logger = logging.getLogger()
##
import requests
import requests.auth
from pyroute2 import IPRoute
##
from . import config
from . import tunnel


class TunnelBroker(object):
    url_ip = 'https://ipv4.clientinfo.square-r00t.net/'
    params_ip = {'raw': '1'}
    url_api = 'https://ipv4.tunnelbroker.net/nic/update'
    ip_cache = '~/.cache/he_tunnelbroker.my_ip.json'

    def __init__(self, conf_xml, tun_id = None, wan_ip = True, update = True, *args, **kwargs):
        self.conf_file = os.path.abspath(os.path.expanduser(conf_xml))
        logger.debug('Using config path: {0}'.format(self.conf_file))
        self._conf = config.Config(self.conf_file)
        if tun_id:
            self.tun = self._conf.tunnels[int(tun_id)]
        else:
            tun_id = list(self._conf.tunnels.keys())[0]
            self.tun = self._conf.tunnels[tun_id]
        self.iface_name = 'he-{0}'.format(self.tun.id)
        self.wan = wan_ip
        self.needs_update = False
        self.force_update = update
        self.ip_cache = os.path.abspath(os.path.expanduser(self.ip_cache))
        self.cached_ips = []
        self.my_ip = None
        self.iface_idx = None

    def _get_my_ip(self):
        if os.path.isfile(self.ip_cache):
            with open(self.ip_cache, 'r') as fh:
                self.cached_ips = [(datetime.datetime.fromtimestamp(i[0]),
                                    tunnel.IP4(i[1], 32)) for i in json.loads(fh.read())]
        else:
            os.makedirs(os.path.dirname(self.ip_cache), exist_ok = True, mode = 0o0700)
        if self.wan:
            logger.debug('WAN IP tunneling enabled; fetching WAN IP.')
            req = requests.get(self.url_ip, params = self.params_ip)
            if not req.ok:
                logger.error('Could not fetch self IP. Request returned {0}.'.format(req.status_code))
                raise RuntimeError('Could not fetch self IP')
            self.my_ip = tunnel.IP4(req.json()['ip'], 32)
            logger.debug('Set my_ip to {0}.'.format(self.my_ip.str))
        else:
            logger.debug('WAN IP tunneling disabled; fetching LAN IP.')
            ipr = IPRoute()
            _defrt = ipr.get_default_routes(family = socket.AF_INET)
            if len(_defrt) != 1:  # This (probably) WILL fail on multipath systems.
                logger.error('Could not determine default route. Does this machine have a single default route?')
                raise RuntimeError('Could not determine default IPv4 route')
            self.my_ip = tunnel.IP4(_defrt[0]['attrs']['RTA_PREFSRC'], 32)
            ipr.close()
            logger.debug('Set my_ip to {0}.'.format(self.my_ip.str))
        chk_tuple = (datetime.datetime.utcnow(), self.my_ip)
        if len(self.cached_ips) >= 1 and self.my_ip.str != self.cached_ips[-1][1].str:
            self.needs_update = True
        elif len(self.cached_ips) == 0:
            self.needs_update = True
        if self.needs_update:
            self.cached_ips.append(chk_tuple)
            with open(self.ip_cache, 'w') as fh:
                fh.write(json.dumps([(i[0].timestamp(), i[1].str) for i in self.cached_ips], indent = 4))
        return(None)

    def start(self):
        self._get_my_ip()
        if any((self.force_update, self.needs_update)):
            logger.debug('IP update forced or needed; updating.')
            self.update()
        logger.debug('Attempting to clean up any pre-existing config')
        try:
            self.stop()
            logger.debug('Pre-existing config removed, continuing')
        except Exception as e:
            logger.debug('Config seems to not exist, continuing')
        ipr = IPRoute()
        try:
            ipr.link('add',
                     ifname = self.iface_name,
                     kind = 'sit',
                     sit_local = self.my_ip.str,
                     sit_remote = self.tun.endpoint.str,
                     sit_ttl = 255)
            logger.debug('Added link {0} successfully.'.format(self.iface_name))
        except Exception as e:
            logger.error('Could not create link for link {0} '
                         '(maybe it already exists?) with local {1} and remote {2}: {3}'.format(self.iface_name,
                                                                                                self.my_ip.str,
                                                                                                self.tun.endpoint.str,
                                                                                                e))
            ipr.close()
            raise e
        try:
            self.iface_idx = ipr.link_lookup(ifname = self.iface_name)[0]
            logger.debug('Found link {0} at index {1}.'.format(self.iface_name, self.iface_idx))
        except Exception as e:
            logger.error('Could not set iface_idx for iface name {0}: {1}'.format(self.iface_name, e))
            ipr.close()
            raise e
        try:
            ipr.addr('add',
                     index = self.iface_idx,
                     address = self.tun.client.str,
                     mask = self.tun.client.prefix,
                     family = socket.AF_INET6)
            logger.debug('Added address {0} to link {1} with prefix {2}.'.format(self.tun.client.str,
                                                                                 self.iface_name,
                                                                                 self.tun.client.prefix))
        except Exception as e:
            logger.error(('Could not add address {0} on link {1}: '
                          '{2}').format(self.tun.client.str, self.iface_name, e))
            ipr.close()
            raise e
        try:
            ipr.link('set', index = self.iface_idx, state = 'up', mtu = 1480)
            logger.debug('Set link {0} status to UP.'.format(self.iface_name))
        except Exception as e:
            logger.error(('Could not bring up link for iface name {0} at index {1}: '
                          '{2}').format(self.iface_name, self.iface_idx, e))
            ipr.close()
            raise e
        try:
            ipr.route('add',
                      dst = 'default',
                      gateway = self.tun.server.str,
                      oif = self.iface_idx,
                      family = socket.AF_INET6)
            logger.debug('Added default route for link {0}.'.format(self.iface_name))
        except Exception as e:
            logger.error(('Could not add default IPv6 route on link {0} with '
                          'gateway {1}: {2}').format(self.iface_name, self.tun.server.str, e))
            ipr.close()
            raise e
        for assignment in self.tun.assignments:
            # The SLAAC prefixes.
            for b in assignment.iface_blocks:
                # Try to remove first in case it's already assigned.
                try:
                    ipr.addr('del',
                             index = assignment.iface_idx,
                             address = str(b.ip),
                             mask = b.prefixlen,
                             family = socket.AF_INET6)
                    logger.debug('Removed {0} with prefix {1} from {2}.'.format(str(b), b.prefixlen, assignment.iface))
                except Exception as e:
                    pass
                try:
                    ipr.addr('add',
                             index = assignment.iface_idx,
                             address = str(b.ip),
                             mask = b.prefixlen,
                             family = socket.AF_INET6)
                    logger.debug('Added {0} with prefix {1} to {2}.'.format(str(b.ip), b.prefixlen, assignment.iface))
                except Exception as e:
                    logger.error(('Could not add address block {0} with prefix {1} on {2}: '
                                  '{3}').format(str(b.ip), b.prefixlen, assignment.iface, e))
                    ipr.close()
                    raise e
        ipr.close()
        if self.tun.ra:
            self.tun.ra.conf.write()
            self.tun.ra.svc.restart()
        return(None)

    def stop(self):
        ipr = IPRoute()
        try:
            self.iface_idx = ipr.link_lookup(ifname = self.iface_name)[0]
            logger.debug('Found link {0} at index {1}.'.format(self.iface_name, self.iface_idx))
        except Exception as e:
            ipr.close()
            logger.error('Could not set iface_idx for link {0}: {1}'.format(self.iface_name, e))
            raise e
        try:
            ipr.route('del',
                      dst = 'default',
                      # gateway = self.def_rt_ip,
                      oif = self.iface_idx,
                      family = socket.AF_INET6)
            logger.debug('Removed default route for link {0}.'.format(self.iface_name))
        except Exception as e:
            logger.error(('Could not remove default IPv6 route on link {0}: '
                          '{1} (continuing anyways)').format(self.iface_name, e))
        try:
            ipr.link('set', index = self.iface_idx, state = 'down')
        except Exception as e:
            logger.error('Could not bring down link {0}: {1} (continuing anyways)'.format(self.iface_name, e))
        try:
            ipr.link('del', index = self.iface_idx)
            logger.debug('Deleted link {0}.'.format(self.iface_name))
        except Exception as e:
            logger.error('Could not delete link {0}: {1}'.format(self.iface_name, e))
            ipr.close()
            raise e
        ipr.close()
        self.tun.ra.svc.stop()
        return(None)

    def update(self):
        if not self.my_ip:
            self._get_my_ip()
        if not self.needs_update:
            return(None)
        auth_handler = requests.auth.HTTPBasicAuth(self.tun.creds.user, self.tun.update_key)
        logger.debug('Set auth handler.')
        logger.debug('Requesting IP update at provider.')
        req = requests.get(self.url_api,
                           params = {'hostname': str(self.tun.id),
                                     'myip': self.my_ip.str},
                           auth = auth_handler)
        if not req.ok:
            logger.error('Could not update IP at provider. Request returned {0}.'.format(req.status_code))
            raise RuntimeError('Could not update client IP in tunnel')
        status = req.content.decode('utf-8').split()[0].strip()
        if status.lower() not in ('good', 'nochg'):
            logger.error('Returned following failure message: {0}'.format(req.content.decode('utf-8')))
            raise RuntimeError('Client IP update returned failure')
        else:
            logger.debug('Returned success message: {0}'.format(req.content.decode('utf-8')))
        return(None)