OpenStack Networking (Neutron)
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# Copyright 2012, Nachi Ueno, NTT MCL, Inc.
# All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import netaddr
from oslo.config import cfg
from neutron.agent import firewall
from neutron.agent.linux import iptables_manager
from neutron.common import constants
from neutron.common import ipv6_utils
from neutron.openstack.common import log as logging
LOG = logging.getLogger(__name__)
SG_CHAIN = 'sg-chain'
INGRESS_DIRECTION = 'ingress'
EGRESS_DIRECTION = 'egress'
SPOOF_FILTER = 'spoof-filter'
CHAIN_NAME_PREFIX = {INGRESS_DIRECTION: 'i',
EGRESS_DIRECTION: 'o',
SPOOF_FILTER: 's'}
LINUX_DEV_LEN = 14
class IptablesFirewallDriver(firewall.FirewallDriver):
"""Driver which enforces security groups through iptables rules."""
IPTABLES_DIRECTION = {INGRESS_DIRECTION: 'physdev-out',
EGRESS_DIRECTION: 'physdev-in'}
def __init__(self):
self.iptables = iptables_manager.IptablesManager(
root_helper=cfg.CONF.AGENT.root_helper,
use_ipv6=ipv6_utils.is_enabled())
# list of port which has security group
self.filtered_ports = {}
self._add_fallback_chain_v4v6()
self._defer_apply = False
self._pre_defer_filtered_ports = None
@property
def ports(self):
return self.filtered_ports
def prepare_port_filter(self, port):
LOG.debug(_("Preparing device (%s) filter"), port['device'])
self._remove_chains()
self.filtered_ports[port['device']] = port
# each security group has it own chains
self._setup_chains()
self.iptables.apply()
def update_port_filter(self, port):
LOG.debug(_("Updating device (%s) filter"), port['device'])
if port['device'] not in self.filtered_ports:
LOG.info(_('Attempted to update port filter which is not '
'filtered %s'), port['device'])
return
self._remove_chains()
self.filtered_ports[port['device']] = port
self._setup_chains()
self.iptables.apply()
def remove_port_filter(self, port):
LOG.debug(_("Removing device (%s) filter"), port['device'])
if not self.filtered_ports.get(port['device']):
LOG.info(_('Attempted to remove port filter which is not '
'filtered %r'), port)
return
self._remove_chains()
self.filtered_ports.pop(port['device'], None)
self._setup_chains()
self.iptables.apply()
def _setup_chains(self):
"""Setup ingress and egress chain for a port."""
if not self._defer_apply:
self._setup_chains_apply(self.filtered_ports)
def _setup_chains_apply(self, ports):
self._add_chain_by_name_v4v6(SG_CHAIN)
for port in ports.values():
self._setup_chain(port, INGRESS_DIRECTION)
self._setup_chain(port, EGRESS_DIRECTION)
self.iptables.ipv4['filter'].add_rule(SG_CHAIN, '-j ACCEPT')
self.iptables.ipv6['filter'].add_rule(SG_CHAIN, '-j ACCEPT')
def _remove_chains(self):
"""Remove ingress and egress chain for a port."""
if not self._defer_apply:
self._remove_chains_apply(self.filtered_ports)
def _remove_chains_apply(self, ports):
for port in ports.values():
self._remove_chain(port, INGRESS_DIRECTION)
self._remove_chain(port, EGRESS_DIRECTION)
self._remove_chain(port, SPOOF_FILTER)
self._remove_chain_by_name_v4v6(SG_CHAIN)
def _setup_chain(self, port, DIRECTION):
self._add_chain(port, DIRECTION)
self._add_rule_by_security_group(port, DIRECTION)
def _remove_chain(self, port, DIRECTION):
chain_name = self._port_chain_name(port, DIRECTION)
self._remove_chain_by_name_v4v6(chain_name)
def _add_fallback_chain_v4v6(self):
self.iptables.ipv4['filter'].add_chain('sg-fallback')
self.iptables.ipv4['filter'].add_rule('sg-fallback', '-j DROP')
self.iptables.ipv6['filter'].add_chain('sg-fallback')
self.iptables.ipv6['filter'].add_rule('sg-fallback', '-j DROP')
def _add_chain_by_name_v4v6(self, chain_name):
self.iptables.ipv6['filter'].add_chain(chain_name)
self.iptables.ipv4['filter'].add_chain(chain_name)
def _remove_chain_by_name_v4v6(self, chain_name):
self.iptables.ipv4['filter'].ensure_remove_chain(chain_name)
self.iptables.ipv6['filter'].ensure_remove_chain(chain_name)
def _add_rule_to_chain_v4v6(self, chain_name, ipv4_rules, ipv6_rules):
for rule in ipv4_rules:
self.iptables.ipv4['filter'].add_rule(chain_name, rule)
for rule in ipv6_rules:
self.iptables.ipv6['filter'].add_rule(chain_name, rule)
def _get_device_name(self, port):
return port['device']
def _add_chain(self, port, direction):
chain_name = self._port_chain_name(port, direction)
self._add_chain_by_name_v4v6(chain_name)
# Note(nati) jump to the security group chain (SG_CHAIN)
# This is needed because the packet may much two rule in port
# if the two port is in the same host
# We accept the packet at the end of SG_CHAIN.
# jump to the security group chain
device = self._get_device_name(port)
jump_rule = ['-m physdev --%s %s --physdev-is-bridged '
'-j $%s' % (self.IPTABLES_DIRECTION[direction],
device,
SG_CHAIN)]
self._add_rule_to_chain_v4v6('FORWARD', jump_rule, jump_rule)
# jump to the chain based on the device
jump_rule = ['-m physdev --%s %s --physdev-is-bridged '
'-j $%s' % (self.IPTABLES_DIRECTION[direction],
device,
chain_name)]
self._add_rule_to_chain_v4v6(SG_CHAIN, jump_rule, jump_rule)
if direction == EGRESS_DIRECTION:
self._add_rule_to_chain_v4v6('INPUT', jump_rule, jump_rule)
def _split_sgr_by_ethertype(self, security_group_rules):
ipv4_sg_rules = []
ipv6_sg_rules = []
for rule in security_group_rules:
if rule.get('ethertype') == constants.IPv4:
ipv4_sg_rules.append(rule)
elif rule.get('ethertype') == constants.IPv6:
if rule.get('protocol') == 'icmp':
rule['protocol'] = 'icmpv6'
ipv6_sg_rules.append(rule)
return ipv4_sg_rules, ipv6_sg_rules
def _select_sgr_by_direction(self, port, direction):
return [rule
for rule in port.get('security_group_rules', [])
if rule['direction'] == direction]
def _setup_spoof_filter_chain(self, port, table, mac_ip_pairs, rules):
if mac_ip_pairs:
chain_name = self._port_chain_name(port, SPOOF_FILTER)
table.add_chain(chain_name)
for mac, ip in mac_ip_pairs:
if ip is None:
# If fixed_ips is [] this rule will be added to the end
# of the list after the allowed_address_pair rules.
table.add_rule(chain_name,
'-m mac --mac-source %s -j RETURN'
% mac)
else:
table.add_rule(chain_name,
'-m mac --mac-source %s -s %s -j RETURN'
% (mac, ip))
table.add_rule(chain_name, '-j DROP')
rules.append('-j $%s' % chain_name)
def _build_ipv4v6_mac_ip_list(self, mac, ip_address, mac_ipv4_pairs,
mac_ipv6_pairs):
if netaddr.IPNetwork(ip_address).version == 4:
mac_ipv4_pairs.append((mac, ip_address))
else:
mac_ipv6_pairs.append((mac, ip_address))
def _spoofing_rule(self, port, ipv4_rules, ipv6_rules):
#Note(nati) allow dhcp or RA packet
ipv4_rules += ['-p udp -m udp --sport 68 --dport 67 -j RETURN']
ipv6_rules += ['-p icmpv6 -j RETURN']
ipv6_rules += ['-p udp -m udp --sport 546 --dport 547 -j RETURN']
mac_ipv4_pairs = []
mac_ipv6_pairs = []
if isinstance(port.get('allowed_address_pairs'), list):
for address_pair in port['allowed_address_pairs']:
self._build_ipv4v6_mac_ip_list(address_pair['mac_address'],
address_pair['ip_address'],
mac_ipv4_pairs,
mac_ipv6_pairs)
for ip in port['fixed_ips']:
self._build_ipv4v6_mac_ip_list(port['mac_address'], ip,
mac_ipv4_pairs, mac_ipv6_pairs)
if not port['fixed_ips']:
mac_ipv4_pairs.append((port['mac_address'], None))
mac_ipv6_pairs.append((port['mac_address'], None))
self._setup_spoof_filter_chain(port, self.iptables.ipv4['filter'],
mac_ipv4_pairs, ipv4_rules)
self._setup_spoof_filter_chain(port, self.iptables.ipv6['filter'],
mac_ipv6_pairs, ipv6_rules)
def _drop_dhcp_rule(self, ipv4_rules, ipv6_rules):
#Note(nati) Drop dhcp packet from VM
ipv4_rules += ['-p udp -m udp --sport 67 --dport 68 -j DROP']
ipv6_rules += ['-p udp -m udp --sport 547 --dport 546 -j DROP']
def _accept_inbound_icmpv6(self):
# Allow multicast listener, neighbor solicitation and
# neighbor advertisement into the instance
icmpv6_rules = []
for icmp6_type in constants.ICMPV6_ALLOWED_TYPES:
icmpv6_rules += ['-p icmpv6 --icmpv6-type %s -j RETURN' %
icmp6_type]
return icmpv6_rules
def _add_rule_by_security_group(self, port, direction):
chain_name = self._port_chain_name(port, direction)
# select rules for current direction
security_group_rules = self._select_sgr_by_direction(port, direction)
# split groups by ip version
# for ipv4, iptables command is used
# for ipv6, iptables6 command is used
ipv4_sg_rules, ipv6_sg_rules = self._split_sgr_by_ethertype(
security_group_rules)
ipv4_iptables_rule = []
ipv6_iptables_rule = []
if direction == EGRESS_DIRECTION:
self._spoofing_rule(port,
ipv4_iptables_rule,
ipv6_iptables_rule)
self._drop_dhcp_rule(ipv4_iptables_rule, ipv6_iptables_rule)
if direction == INGRESS_DIRECTION:
ipv6_iptables_rule += self._accept_inbound_icmpv6()
ipv4_iptables_rule += self._convert_sgr_to_iptables_rules(
ipv4_sg_rules)
ipv6_iptables_rule += self._convert_sgr_to_iptables_rules(
ipv6_sg_rules)
self._add_rule_to_chain_v4v6(chain_name,
ipv4_iptables_rule,
ipv6_iptables_rule)
def _convert_sgr_to_iptables_rules(self, security_group_rules):
iptables_rules = []
self._drop_invalid_packets(iptables_rules)
self._allow_established(iptables_rules)
for rule in security_group_rules:
# These arguments MUST be in the format iptables-save will
# display them: source/dest, protocol, sport, dport, target
# Otherwise the iptables_manager code won't be able to find
# them to preserve their [packet:byte] counts.
args = self._ip_prefix_arg('s',
rule.get('source_ip_prefix'))
args += self._ip_prefix_arg('d',
rule.get('dest_ip_prefix'))
args += self._protocol_arg(rule.get('protocol'))
args += self._port_arg('sport',
rule.get('protocol'),
rule.get('source_port_range_min'),
rule.get('source_port_range_max'))
args += self._port_arg('dport',
rule.get('protocol'),
rule.get('port_range_min'),
rule.get('port_range_max'))
args += ['-j RETURN']
iptables_rules += [' '.join(args)]
iptables_rules += ['-j $sg-fallback']
return iptables_rules
def _drop_invalid_packets(self, iptables_rules):
# Always drop invalid packets
iptables_rules += ['-m state --state ' 'INVALID -j DROP']
return iptables_rules
def _allow_established(self, iptables_rules):
# Allow established connections
iptables_rules += ['-m state --state RELATED,ESTABLISHED -j RETURN']
return iptables_rules
def _protocol_arg(self, protocol):
if not protocol:
return []
iptables_rule = ['-p', protocol]
# iptables always adds '-m protocol' for udp and tcp
if protocol in ['udp', 'tcp']:
iptables_rule += ['-m', protocol]
return iptables_rule
def _port_arg(self, direction, protocol, port_range_min, port_range_max):
if (protocol not in ['udp', 'tcp', 'icmp', 'icmpv6']
or not port_range_min):
return []
if protocol in ['icmp', 'icmpv6']:
# Note(xuhanp): port_range_min/port_range_max represent
# icmp type/code when protocol is icmp or icmpv6
# icmp code can be 0 so we cannot use "if port_range_max" here
if port_range_max is not None:
return ['--%s-type' % protocol,
'%s/%s' % (port_range_min, port_range_max)]
return ['--%s-type' % protocol, '%s' % port_range_min]
elif port_range_min == port_range_max:
return ['--%s' % direction, '%s' % (port_range_min,)]
else:
return ['-m', 'multiport',
'--%ss' % direction,
'%s:%s' % (port_range_min, port_range_max)]
def _ip_prefix_arg(self, direction, ip_prefix):
#NOTE (nati) : source_group_id is converted to list of source_
# ip_prefix in server side
if ip_prefix:
return ['-%s' % direction, ip_prefix]
return []
def _port_chain_name(self, port, direction):
return iptables_manager.get_chain_name(
'%s%s' % (CHAIN_NAME_PREFIX[direction], port['device'][3:]))
def filter_defer_apply_on(self):
if not self._defer_apply:
self.iptables.defer_apply_on()
self._pre_defer_filtered_ports = dict(self.filtered_ports)
self._defer_apply = True
def filter_defer_apply_off(self):
if self._defer_apply:
self._defer_apply = False
self._remove_chains_apply(self._pre_defer_filtered_ports)
self._pre_defer_filtered_ports = None
self._setup_chains_apply(self.filtered_ports)
self.iptables.defer_apply_off()
class OVSHybridIptablesFirewallDriver(IptablesFirewallDriver):
OVS_HYBRID_TAP_PREFIX = 'tap'
def _port_chain_name(self, port, direction):
return iptables_manager.get_chain_name(
'%s%s' % (CHAIN_NAME_PREFIX[direction], port['device']))
def _get_device_name(self, port):
return (self.OVS_HYBRID_TAP_PREFIX + port['device'])[:LINUX_DEV_LEN]