From 822e171a0023c3f8f335cda08bcbf70b2d6d4070 Mon Sep 17 00:00:00 2001
From: Christian Poessinger <christian@poessinger.com>
Date: Sat, 28 Mar 2020 11:28:05 +0100
Subject: ipv6: T1831: migrate eui64 addressing to XML and python

---
 python/vyos/ifconfig/interface.py | 38 ++++++++++++++++++++++++++++++++++++--
 python/vyos/util.py               | 22 ++++++++++++++++++++++
 2 files changed, 58 insertions(+), 2 deletions(-)

(limited to 'python/vyos')

diff --git a/python/vyos/ifconfig/interface.py b/python/vyos/ifconfig/interface.py
index a2d202466..8b41d6158 100644
--- a/python/vyos/ifconfig/interface.py
+++ b/python/vyos/ifconfig/interface.py
@@ -21,10 +21,10 @@ import time
 from copy import deepcopy
 
 from vyos.validate import *     # should not * include
-from vyos.config import Config  # not used anymore
+from vyos.util import mac2eui64
 from vyos import ConfigError
 
-from ipaddress import IPv4Network, IPv6Address
+from ipaddress import IPv4Network, IPv6Address, IPv6Network
 from netifaces import ifaddresses, AF_INET, AF_INET6
 from time import sleep
 from os.path import isfile
@@ -393,6 +393,40 @@ class Interface(DHCP):
         """
         return self.set_interface('ipv6_autoconf', autoconf)
 
+    def set_ipv6_eui64_address(self, prefix):
+        """
+        Extended Unique Identifier (EUI), as per RFC2373, allows a host to
+        assign iteslf a unique IPv6 address based on a given IPv6 prefix.
+
+        If prefix is passed address is assigned, if prefix is '' address is
+        removed from interface.
+        """
+        # if prefix is an empty string convert it to None so mac2eui64 works
+        # as expected
+        if not prefix:
+            prefix = None
+
+        eui64 = mac2eui64(self.get_mac(), prefix)
+
+        if not prefix:
+            # if prefix is empty - thus removed - we need to walk through all
+            # interface IPv6 addresses and find the one with the calculated
+            # EUI-64 identifier. The address is then removed
+            for addr in self.get_addr():
+                addr_wo_prefix = addr.split('/')[0]
+                if is_ipv6(addr_wo_prefix):
+                    if eui64 in IPv6Address(addr_wo_prefix).exploded:
+                        self.del_addr(addr)
+
+            return None
+
+        # calculate and add EUI-64 IPv6 address
+        if IPv6Network(prefix):
+            # we also need to take the subnet length into account
+            prefix = prefix.split('/')[1]
+            eui64 = f'{eui64}/{prefix}'
+            self.add_addr(eui64 )
+
     def set_ipv6_forwarding(self, forwarding):
         """
         Configure IPv6 interface-specific Host/Router behaviour.
diff --git a/python/vyos/util.py b/python/vyos/util.py
index e8727c192..635b11ee5 100644
--- a/python/vyos/util.py
+++ b/python/vyos/util.py
@@ -207,3 +207,25 @@ def is_admin() -> bool:
     current_user = getuser()
     (_, _, _, admin_group_members) = getgrnam('sudo')
     return current_user in admin_group_members
+
+
+def mac2eui64(mac, prefix=None):
+    '''
+    Convert a MAC address to a EUI64 address or, with prefix provided, a full
+    IPv6 address.
+    Thankfully copied from https://gist.github.com/wido/f5e32576bb57b5cc6f934e177a37a0d3
+    '''
+    # http://tools.ietf.org/html/rfc4291#section-2.5.1
+    eui64 = re.sub(r'[.:-]', '', mac).lower()
+    eui64 = eui64[0:6] + 'fffe' + eui64[6:]
+    eui64 = hex(int(eui64[0:2], 16) ^ 2)[2:].zfill(2) + eui64[2:]
+
+    if prefix is None:
+        return ':'.join(re.findall(r'.{4}', eui64))
+    else:
+        try:
+            net = ip_network(prefix, strict=False)
+            euil = int('0x{0}'.format(eui64), 16)
+            return str(net[euil])
+        except:  # pylint: disable=bare-except
+            return
-- 
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