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interface.py
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	# Copyright 2019-2020 VyOS maintainers and contributors <maintainers@vyos.io>
	#
	# This library is free software; you can redistribute it and/or
	# modify it under the terms of the GNU Lesser General Public
	# License as published by the Free Software Foundation; either
	# version 2.1 of the License, or (at your option) any later version.
	#
	# This library is distributed in the hope that it will be useful,
	# but WITHOUT ANY WARRANTY; without even the implied warranty of
	# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	# Lesser General Public License for more details.
	#
	# You should have received a copy of the GNU Lesser General Public
	# License along with this library. If not, see <http://www.gnu.org/licenses/>.

	import os
	import re
	import json
	from copy import deepcopy

	from ipaddress import IPv4Network
	from ipaddress import IPv6Address
	from ipaddress import IPv6Network
	from netifaces import ifaddresses
	# this is not the same as socket.AF_INET/INET6
	from netifaces import AF_INET
	from netifaces import AF_INET6

	from vyos import ConfigError
	from vyos.util import mac2eui64
	from vyos.validate import is_ipv4
	from vyos.validate import is_ipv6
	from vyos.validate import is_intf_addr_assigned
	from vyos.validate import assert_boolean
	from vyos.validate import assert_list
	from vyos.validate import assert_mac
	from vyos.validate import assert_mtu
	from vyos.validate import assert_positive
	from vyos.validate import assert_range

	from vyos.ifconfig.control import Control
	from vyos.ifconfig.dhcp import DHCP
	from vyos.ifconfig.vrrp import VRRP
	from vyos.ifconfig.operational import Operational


	class Interface(Control):
	# This is the class which will be used to create
	# self.operational, it allows subclasses, such as
	# WireGuard to modify their display behaviour
	OperationalClass = Operational

	options = ['debug', 'create',]
	required = []
	default = {
	'type': '',
	'debug': True,
	'create': True,
	}
	definition = {
	'section': '',
	'prefixes': [],
	'vlan': False,
	'bondable': False,
	'broadcast': False,
	'bridgeable': False,
	'eternal': '',
	}

	_command_get = {
	'admin_state': {
	'shellcmd': 'ip -json link show dev {ifname}',
	'format': lambda j: 'up' if 'UP' in json.loads(j)[0]['flags'] else 'down',
	}
	}

	_command_set = {
	'admin_state': {
	'validate': lambda v: assert_list(v, ['up', 'down']),
	'shellcmd': 'ip link set dev {ifname} {value}',
	},
	'mac': {
	'validate': assert_mac,
	'shellcmd': 'ip link set dev {ifname} address {value}',
	},
	'vrf': {
	'convert': lambda v: f'master {v}' if v else 'nomaster',
	'shellcmd': 'ip link set dev {ifname} {value}',
	},
	}

	_sysfs_get = {
	'alias': {
	'location': '/sys/class/net/{ifname}/ifalias',
	},
	'mac': {
	'location': '/sys/class/net/{ifname}/address',
	},
	'mtu': {
	'location': '/sys/class/net/{ifname}/mtu',
	},
	'oper_state':{
	'location': '/sys/class/net/{ifname}/operstate',
	},
	}

	_sysfs_set = {
	'alias': {
	'convert': lambda name: name if name else '\0',
	'location': '/sys/class/net/{ifname}/ifalias',
	},
	'mtu': {
	'validate': assert_mtu,
	'location': '/sys/class/net/{ifname}/mtu',
	},
	'arp_cache_tmo': {
	'convert': lambda tmo: (int(tmo) * 1000),
	'location': '/proc/sys/net/ipv4/neigh/{ifname}/base_reachable_time_ms',
	},
	'arp_filter': {
	'validate': assert_boolean,
	'location': '/proc/sys/net/ipv4/conf/{ifname}/arp_filter',
	},
	'arp_accept': {
	'validate': lambda arp: assert_range(arp,0,2),
	'location': '/proc/sys/net/ipv4/conf/{ifname}/arp_accept',
	},
	'arp_announce': {
	'validate': assert_boolean,
	'location': '/proc/sys/net/ipv4/conf/{ifname}/arp_announce',
	},
	'arp_ignore': {
	'validate': assert_boolean,
	'location': '/proc/sys/net/ipv4/conf/{ifname}/arp_ignore',
	},
	'ipv6_autoconf': {
	'validate': lambda fwd: assert_range(fwd,0,2),
	'location': '/proc/sys/net/ipv6/conf/{ifname}/autoconf',
	},
	'ipv6_forwarding': {
	'validate': lambda fwd: assert_range(fwd,0,2),
	'location': '/proc/sys/net/ipv6/conf/{ifname}/forwarding',
	},
	'ipv6_dad_transmits': {
	'validate': assert_positive,
	'location': '/proc/sys/net/ipv6/conf/{ifname}/dad_transmits',
	},
	'proxy_arp': {
	'validate': assert_boolean,
	'location': '/proc/sys/net/ipv4/conf/{ifname}/proxy_arp',
	},
	'proxy_arp_pvlan': {
	'validate': assert_boolean,
	'location': '/proc/sys/net/ipv4/conf/{ifname}/proxy_arp_pvlan',
	},
	# link_detect vs link_filter name weirdness
	'link_detect': {
	'validate': lambda link: assert_range(link,0,3),
	'location': '/proc/sys/net/ipv4/conf/{ifname}/link_filter',
	},
	}

	@classmethod
	def exists(cls, ifname):
	return os.path.exists(f'/sys/class/net/{ifname}')

	def __init__(self, ifname, **kargs):
	"""
	This is the base interface class which supports basic IP/MAC address
	operations as well as DHCP(v6). Other interface which represent e.g.
	and ethernet bridge are implemented as derived classes adding all
	additional functionality.

	For creation you will need to provide the interface type, otherwise
	the existing interface is used

	DEBUG:
	This class has embedded debugging (print) which can be enabled by
	creating the following file:
	vyos@vyos# touch /tmp/vyos.ifconfig.debug

	Example:
	>>> from vyos.ifconfig import Interface
	>>> i = Interface('eth0')
	"""

	self.config = deepcopy(self.default)
	for k in self.options:
	if k in kargs:
	self.config[k] = kargs[k]

	# make sure the ifname is the first argument and not from the dict
	self.config['ifname'] = ifname

	# we must have updated config before initialising the Interface
	super().__init__(**kargs)
	self.ifname = ifname
	self.dhcp = DHCP(ifname)

	if not self.exists(ifname):
	# Any instance of Interface, such as Interface('eth0')
	# can be used safely to access the generic function in this class
	# as 'type' is unset, the class can not be created
	if not self.config['type']:
	raise Exception(f'interface "{ifname}" not found')

	# Should an Instance of a child class (EthernetIf, DummyIf, ..)
	# be required, then create should be set to False to not accidentally create it.
	# In case a subclass does not define it, we use get to set the default to True
	if self.config.get('create',True):
	for k in self.required:
	if k not in kargs:
	name = self.default['type']
	raise ConfigError(f'missing required option {k} for {name} {ifname} creation')

	self._create()
	# If we can not connect to the interface then let the caller know
	# as the class could not be correctly initialised
	else:
	raise Exception('interface "{}" not found'.format(self.config['ifname']))

	# temporary list of assigned IP addresses
	self._addr = []

	self.operational = self.OperationalClass(ifname)
	self.vrrp = VRRP(ifname)

	def _create(self):
	cmd = 'ip link add dev {ifname} type {type}'.format(**self.config)
	self._cmd(cmd)

	def remove(self):
	"""
	Remove interface from operating system. Removing the interface
	deconfigures all assigned IP addresses and clear possible DHCP(v6)
	client processes.

	Example:
	>>> from vyos.ifconfig import Interface
	>>> i = Interface('eth0')
	>>> i.remove()
	"""
	# stop DHCP(v6) if running
	self.dhcp.v4.delete()
	self.dhcp.v6.delete()

	# remove all assigned IP addresses from interface - this is a bit redundant
	# as the kernel will remove all addresses on interface deletion, but we
	# can not delete ALL interfaces, see below
	for addr in self.get_addr():
	self.del_addr(addr)

	# ---------------------------------------------------------------------
	# Any class can define an eternal regex in its definition
	# interface matching the regex will not be deleted

	eternal = self.definition['eternal']
	if not eternal:
	self._delete()
	elif not re.match(eternal, self.ifname):
	self._delete()

	def _delete(self):
	# NOTE (Improvement):
	# after interface removal no other commands should be allowed
	# to be called and instead should raise an Exception:
	cmd = 'ip link del dev {}'.format(self.config['ifname'])
	return self._cmd(cmd)

	def get_mtu(self):
	"""
	Get/set interface mtu in bytes.

	Example:
	>>> from vyos.ifconfig import Interface
	>>> Interface('eth0').get_mtu()
	'1500'
	"""
	return self.get_interface('mtu')

	def set_mtu(self, mtu):
	"""
	Get/set interface mtu in bytes.

	Example:
	>>> from vyos.ifconfig import Interface
	>>> Interface('eth0').set_mtu(1400)
	>>> Interface('eth0').get_mtu()
	'1400'
	"""
	return self.set_interface('mtu', mtu)

	def get_mac(self):
	"""
	Get current interface MAC (Media Access Contrl) address used.

	Example:
	>>> from vyos.ifconfig import Interface
	>>> Interface('eth0').get_mac()
	'00:50:ab:cd:ef:00'
	"""
	return self.get_interface('mac')

	def set_mac(self, mac):
	"""
	Set interface MAC (Media Access Contrl) address to given value.

	Example:
	>>> from vyos.ifconfig import Interface
	>>> Interface('eth0').set_mac('00:50:ab:cd:ef:01')
	"""

	# If MAC is unchanged, bail out early
	if mac == self.get_mac():
	return None

	# MAC address can only be changed if interface is in 'down' state
	prev_state = self.get_admin_state()
	if prev_state == 'up':
	self.set_admin_state('down')

	self.set_interface('mac', mac)

	def set_vrf(self, vrf=''):
	"""
	Add/Remove interface from given VRF instance.

	Example:
	>>> from vyos.ifconfig import Interface
	>>> Interface('eth0').set_vrf('foo')
	>>> Interface('eth0').set_vrf()
	"""
	self.set_interface('vrf', vrf)

	def set_arp_cache_tmo(self, tmo):
	"""
	Set ARP cache timeout value in seconds. Internal Kernel representation
	is in milliseconds.

	Example:
	>>> from vyos.ifconfig import Interface
	>>> Interface('eth0').set_arp_cache_tmo(40)
	"""
	return self.set_interface('arp_cache_tmo', tmo)

	def set_arp_filter(self, arp_filter):
	"""
	Filter ARP requests

	1 - Allows you to have multiple network interfaces on the same
	subnet, and have the ARPs for each interface be answered
	based on whether or not the kernel would route a packet from
	the ARP'd IP out that interface (therefore you must use source
	based routing for this to work). In other words it allows control
	of which cards (usually 1) will respond to an arp request.

	0 - (default) The kernel can respond to arp requests with addresses
	from other interfaces. This may seem wrong but it usually makes
	sense, because it increases the chance of successful communication.
	IP addresses are owned by the complete host on Linux, not by
	particular interfaces. Only for more complex setups like load-
	balancing, does this behaviour cause problems.
	"""
	return self.set_interface('arp_filter', arp_filter)

	def set_arp_accept(self, arp_accept):
	"""
	Define behavior for gratuitous ARP frames who's IP is not
	already present in the ARP table:
	0 - don't create new entries in the ARP table
	1 - create new entries in the ARP table

	Both replies and requests type gratuitous arp will trigger the
	ARP table to be updated, if this setting is on.

	If the ARP table already contains the IP address of the
	gratuitous arp frame, the arp table will be updated regardless
	if this setting is on or off.
	"""
	return self.set_interface('arp_accept', arp_accept)

	def set_arp_announce(self, arp_announce):
	"""
	Define different restriction levels for announcing the local
	source IP address from IP packets in ARP requests sent on
	interface:
	0 - (default) Use any local address, configured on any interface
	1 - Try to avoid local addresses that are not in the target's
	subnet for this interface. This mode is useful when target
	hosts reachable via this interface require the source IP
	address in ARP requests to be part of their logical network
	configured on the receiving interface. When we generate the
	request we will check all our subnets that include the
	target IP and will preserve the source address if it is from
	such subnet.

	Increasing the restriction level gives more chance for
	receiving answer from the resolved target while decreasing
	the level announces more valid sender's information.
	"""
	return self.set_interface('arp_announce', arp_announce)

	def set_arp_ignore(self, arp_ignore):
	"""
	Define different modes for sending replies in response to received ARP
	requests that resolve local target IP addresses:

	0 - (default): reply for any local target IP address, configured
	on any interface
	1 - reply only if the target IP address is local address
	configured on the incoming interface
	"""
	return self.set_interface('arp_ignore', arp_ignore)

	def set_ipv6_autoconf(self, autoconf):
	"""
	Autoconfigure addresses using Prefix Information in Router
	Advertisements.
	"""
	return self.set_interface('ipv6_autoconf', autoconf)

	def add_ipv6_eui64_address(self, prefix):
	"""
	Extended Unique Identifier (EUI), as per RFC2373, allows a host to
	assign itself a unique IPv6 address based on a given IPv6 prefix.

	Calculate the EUI64 from the interface's MAC, then assign it
	with the given prefix to the interface.
	"""

	eui64 = mac2eui64(self.get_mac(), prefix)
	prefixlen = prefix.split('/')[1]
	self.add_addr(f'{eui64}/{prefixlen}')

	def del_ipv6_eui64_address(self, prefix):
	"""
	Delete the address based on the interface's MAC-based EUI64
	combined with the prefix address.
	"""
	eui64 = mac2eui64(self.get_mac(), prefix)
	prefixlen = prefix.split('/')[1]
	self.del_addr(f'{eui64}/{prefixlen}')


	def set_ipv6_forwarding(self, forwarding):
	"""
	Configure IPv6 interface-specific Host/Router behaviour.

	False:

	By default, Host behaviour is assumed. This means:

	1. IsRouter flag is not set in Neighbour Advertisements.
	2. If accept_ra is TRUE (default), transmit Router
	Solicitations.
	3. If accept_ra is TRUE (default), accept Router
	Advertisements (and do autoconfiguration).
	4. If accept_redirects is TRUE (default), accept Redirects.

	True:

	If local forwarding is enabled, Router behaviour is assumed.
	This means exactly the reverse from the above:

	1. IsRouter flag is set in Neighbour Advertisements.
	2. Router Solicitations are not sent unless accept_ra is 2.
	3. Router Advertisements are ignored unless accept_ra is 2.
	4. Redirects are ignored.
	"""
	return self.set_interface('ipv6_forwarding', forwarding)

	def set_ipv6_dad_messages(self, dad):
	"""
	The amount of Duplicate Address Detection probes to send.
	Default: 1
	"""
	return self.set_interface('ipv6_dad_transmits', dad)

	def set_link_detect(self, link_filter):
	"""
	Configure kernel response in packets received on interfaces that are 'down'

	0 - Allow packets to be received for the address on this interface
	even if interface is disabled or no carrier.

	1 - Ignore packets received if interface associated with the incoming
	address is down.

	2 - Ignore packets received if interface associated with the incoming
	address is down or has no carrier.

	Default value is 0. Note that some distributions enable it in startup
	scripts.

	Example:
	>>> from vyos.ifconfig import Interface
	>>> Interface('eth0').set_link_detect(1)
	"""
	return self.set_interface('link_detect', link_filter)

	def get_alias(self):
	"""
	Get interface alias name used by e.g. SNMP

	Example:
	>>> Interface('eth0').get_alias()
	'interface description as set by user'
	"""
	return self.get_interface('alias')

	def set_alias(self, ifalias=''):
	"""
	Set interface alias name used by e.g. SNMP

	Example:
	>>> from vyos.ifconfig import Interface
	>>> Interface('eth0').set_alias('VyOS upstream interface')

	to clear alias e.g. delete it use:

	>>> Interface('eth0').set_ifalias('')
	"""
	self.set_interface('alias', ifalias)

	def get_admin_state(self):
	"""
	Get interface administrative state. Function will return 'up' or 'down'

	Example:
	>>> from vyos.ifconfig import Interface
	>>> Interface('eth0').get_admin_state()
	'up'
	"""
	return self.get_interface('admin_state')

	def set_admin_state(self, state):
	"""
	Set interface administrative state to be 'up' or 'down'

	Example:
	>>> from vyos.ifconfig import Interface
	>>> Interface('eth0').set_admin_state('down')
	>>> Interface('eth0').get_admin_state()
	'down'
	"""
	return self.set_interface('admin_state', state)

	def set_proxy_arp(self, enable):
	"""
	Set per interface proxy ARP configuration

	Example:
	>>> from vyos.ifconfig import Interface
	>>> Interface('eth0').set_proxy_arp(1)
	"""
	self.set_interface('proxy_arp', enable)

	def set_proxy_arp_pvlan(self, enable):
	"""
	Private VLAN proxy arp.
	Basically allow proxy arp replies back to the same interface
	(from which the ARP request/solicitation was received).

	This is done to support (ethernet) switch features, like RFC
	3069, where the individual ports are NOT allowed to
	communicate with each other, but they are allowed to talk to
	the upstream router. As described in RFC 3069, it is possible
	to allow these hosts to communicate through the upstream
	router by proxy_arp'ing. Don't need to be used together with
	proxy_arp.

	This technology is known by different names:
	In RFC 3069 it is called VLAN Aggregation.
	Cisco and Allied Telesyn call it Private VLAN.
	Hewlett-Packard call it Source-Port filtering or port-isolation.
	Ericsson call it MAC-Forced Forwarding (RFC Draft).

	Example:
	>>> from vyos.ifconfig import Interface
	>>> Interface('eth0').set_proxy_arp_pvlan(1)
	"""
	self.set_interface('proxy_arp_pvlan', enable)

	def get_addr(self):
	"""
	Retrieve assigned IPv4 and IPv6 addresses from given interface.
	This is done using the netifaces and ipaddress python modules.

	Example:
	>>> from vyos.ifconfig import Interface
	>>> Interface('eth0').get_addrs()
	['172.16.33.30/24', 'fe80::20c:29ff:fe11:a174/64']
	"""

	ipv4 = []
	ipv6 = []

	if AF_INET in ifaddresses(self.config['ifname']).keys():
	for v4_addr in ifaddresses(self.config['ifname'])[AF_INET]:
	# we need to manually assemble a list of IPv4 address/prefix
	prefix = '/' + \
	str(IPv4Network('0.0.0.0/' + v4_addr['netmask']).prefixlen)
	ipv4.append(v4_addr['addr'] + prefix)

	if AF_INET6 in ifaddresses(self.config['ifname']).keys():
	for v6_addr in ifaddresses(self.config['ifname'])[AF_INET6]:
	# Note that currently expanded netmasks are not supported. That means
	# 2001:db00::0/24 is a valid argument while 2001:db00::0/ffff:ff00:: not.
	# see https://docs.python.org/3/library/ipaddress.html
	bits = bin(
	int(v6_addr['netmask'].replace(':', ''), 16)).count('1')
	prefix = '/' + str(bits)

	# we alsoneed to remove the interface suffix on link local
	# addresses
	v6_addr['addr'] = v6_addr['addr'].split('%')[0]
	ipv6.append(v6_addr['addr'] + prefix)

	return ipv4 + ipv6

	def add_addr(self, addr):
	"""
	Add IP(v6) address to interface. Address is only added if it is not
	already assigned to that interface. Address format must be validated
	and compressed/normalized before calling this function.

	addr: can be an IPv4 address, IPv6 address, dhcp or dhcpv6!
	IPv4: add IPv4 address to interface
	IPv6: add IPv6 address to interface
	dhcp: start dhclient (IPv4) on interface
	dhcpv6: start dhclient (IPv6) on interface

	Returns False if address is already assigned and wasn't re-added.
	Example:
	>>> from vyos.ifconfig import Interface
	>>> j = Interface('eth0')
	>>> j.add_addr('192.0.2.1/24')
	>>> j.add_addr('2001:db8::ffff/64')
	>>> j.get_addr()
	['192.0.2.1/24', '2001:db8::ffff/64']
	"""
	# XXX: normalize/compress with ipaddress if calling functions don't?
	# is subnet mask always passed, and in the same way?
	ret = True

	# we can't have both DHCP and static IPv4 addresses assigned
	for a in self._addr:
	if ( ( addr == 'dhcp' and a != 'dhcpv6' and is_ipv4(a) ) or
	( a == 'dhcp' and addr != 'dhcpv6' and is_ipv4(addr) ) ):
	raise ConfigError((
	"Can't configure both static IPv4 and DHCP address "
	"on the same interface"))

	# do not add same address twice
	if addr not in self._addr:
	# add to interface
	if addr == 'dhcp':
	self.dhcp.v4.set()
	elif addr == 'dhcpv6':
	self.dhcp.v6.set()
	else:
	if not is_intf_addr_assigned(self.ifname, addr):
	ret = self._cmd(f'ip addr add "{addr}" dev "{self.ifname}"')
	else:
	return False
	# add to cache
	self._addr.append(addr)
	else:
	return False

	return ret

	def del_addr(self, addr):
	"""
	Delete IP(v6) address from interface. Address is only deleted if it is
	assigned to that interface. Address format must be exactly the same as
	was used when adding the address.

	addr: can be an IPv4 address, IPv6 address, dhcp or dhcpv6!
	IPv4: delete IPv4 address from interface
	IPv6: delete IPv6 address from interface
	dhcp: stop dhclient (IPv4) on interface
	dhcpv6: stop dhclient (IPv6) on interface

	Returns False if address isn't already assigned and wasn't deleted.
	Example:
	>>> from vyos.ifconfig import Interface
	>>> j = Interface('eth0')
	>>> j.add_addr('2001:db8::ffff/64')
	>>> j.add_addr('192.0.2.1/24')
	>>> j.get_addr()
	['192.0.2.1/24', '2001:db8::ffff/64']
	>>> j.del_addr('192.0.2.1/24')
	>>> j.get_addr()
	['2001:db8::ffff/64']
	"""
	ret = True

	# remove from interface
	if addr == 'dhcp':
	self.dhcp.v4.delete()
	elif addr == 'dhcpv6':
	self.dhcp.v6.delete()
	else:
	if is_intf_addr_assigned(self.ifname, addr):
	ret = self._cmd(f'ip addr del "{addr}" dev "{self.ifname}"')
	else:
	return False

	if addr in self._addr:
	# remove from cache
	self._addr.remove(addr)

	return ret

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