Advertise ipv6 link local address (sonic-net#1402)

Author: sumukhatv

scripts/neighbor_advertiser

@@ -11,6 +11,7 @@ import argparse
 import json
 import os
 import requests
+import subprocess
 import sys
 import time
 import traceback
@@ -233,6 +234,21 @@ def get_vlan_addresses(vlan_interface):
     ipv4_addr, ipv4_prefix = get_vlan_addr_prefix(vlan_interface, 4)
     ipv6_addr, ipv6_prefix = get_vlan_addr_prefix(vlan_interface, 6)
 
+    if len(ipv6_addr):
+        try:
+            out = subprocess.check_output(['ip', '-6', 'addr', 'show', vlan_interface])
+            out = out.decode('UTF-8')
+            for line in out.splitlines():
+                keys = line.split()
+                if keys[0] == 'inet6':
+                    ip = IPNetwork(keys[1])
+                    if str(ip.ip).startswith("fe80") and str(ip.ip) not in ipv6_addr:
+                        # Link local ipv6 address
+                        ipv6_addr.append(str(ip.ip))
+                        ipv6_prefix.append('128')
+        except Exception:
+            log.log_error('failed to get %s addresses from o.s.' % vlan_interface)
+
     metadata = config_db.get_table('DEVICE_METADATA')
     mac_addr = metadata['localhost']['mac']
     if not mac_addr:

tests/neighbor_advertiser_test.py

@@ -1,6 +1,7 @@
 import sys
 import os
 import pytest
+import subprocess
 from swsscommon.swsscommon import ConfigDBConnector
 
 test_path = os.path.dirname(os.path.abspath(__file__))
@@ -19,6 +20,16 @@ def set_up(self):
         neighbor_advertiser.connect_app_db()
 
     def test_neighbor_advertiser_slice(self, set_up):
+        cmd = "sudo sysctl -w net.ipv6.conf.all.disable_ipv6=0"
+        subprocess.check_output(cmd.split())
+        cmd = "sudo ip link add Vlan1000 type dummy"
+        subprocess.check_output(cmd.split())
+        cmd = "sudo ip -6 address add dev Vlan1000 scope link fe80::1e34:daff:fe1e:2800/64"
+        subprocess.check_output(cmd.split())
+        cmd = "sudo ip link add Vlan2000 type dummy"
+        subprocess.check_output(cmd.split())
+        cmd = "sudo ip -6 address add dev Vlan2000 scope link fe80::1e43:dfaf:fe2e:1800/64"
+        subprocess.check_output(cmd.split())
         output = neighbor_advertiser.construct_neighbor_advertiser_slice()
         expected_output = dict(
             {
@@ -29,7 +40,8 @@ def test_neighbor_advertiser_slice(self, set_up):
                             {'macAddr': '1d:34:db:16:a6:00', 'ipAddr': '192.168.0.1', 'ipPrefixLen': '32'}
                         ],
                         'ipv6AddrMappings': [
-                            {'macAddr': '1d:34:db:16:a6:00', 'ipAddr': 'fc02:1000::1', 'ipPrefixLen': '128'}
+                            {'macAddr': '1d:34:db:16:a6:00', 'ipAddr': 'fc02:1000::1', 'ipPrefixLen': '128'},
+                            {'macAddr': '1d:34:db:16:a6:00', 'ipAddr': 'fe80::1e34:daff:fe1e:2800', 'ipPrefixLen': '128'}
                         ],
                         'vxlanId': '1000',
                         'vlanId': '1000',
@@ -40,7 +52,8 @@ def test_neighbor_advertiser_slice(self, set_up):
                             {'macAddr': '1d:34:db:16:a6:00', 'ipAddr': '192.168.0.10', 'ipPrefixLen': '21'}
                         ],
                         'ipv6AddrMappings': [
-                            {'macAddr': '1d:34:db:16:a6:00', 'ipAddr': 'fc02:1011::1', 'ipPrefixLen': '64'}
+                            {'macAddr': '1d:34:db:16:a6:00', 'ipAddr': 'fc02:1011::1', 'ipPrefixLen': '64'},
+                            {'macAddr': '1d:34:db:16:a6:00', 'ipAddr': 'fe80::1e43:dfaf:fe2e:1800', 'ipPrefixLen': '128'}
                         ],
                         'vxlanId': '2000',
                         'vlanId': '2000',