modified down rules to pre-down rules to ensure that default route is… (sonic-net#3853)

* modified down rules to pre-down rules to ensure that default route is deleted just before interface is made down

Author: kannankvs

files/image_config/interfaces/interfaces.j2

@@ -5,23 +5,23 @@
 # file: /etc/network/interfaces
 #
 {% endblock banner %}
+{% block mgmt_vrf %}
 {% if (MGMT_VRF_CONFIG) and (MGMT_VRF_CONFIG['vrf_global']['mgmtVrfEnabled'] == "true") %}
 auto mgmt
 iface mgmt
     vrf-table 5000
-{% endif %}
-{% block loopback %}
-# The loopback network interface
-auto lo
-iface lo inet loopback
-{% if (MGMT_VRF_CONFIG) and (MGMT_VRF_CONFIG['vrf_global']['mgmtVrfEnabled'] == "true") %}
 # The loopback network interface for mgmt VRF that is required for applications like NTP
     up ip link add lo-m type dummy
+    up ip link set dev lo-m master mgmt
     up ip addr add 127.0.0.1/8 dev lo-m
     up ip link set lo-m up
-    up ip link set dev lo-m master mgmt
-	down ip link delete dev lo-m
+    down ip link delete dev lo-m
 {% endif %}
+{% endblock mgmt_vrf %}
+{% block loopback %}
+# The loopback network interface
+auto lo
+iface lo inet loopback
 {% endblock loopback %}
 {% block mgmt_interface %}
 
@@ -50,14 +50,14 @@ iface eth0 {{ 'inet' if prefix | ipv4 else 'inet6' }} static
     up ip rule add to {{ route }} table {{ vrf_table }}
 {% endfor %}
     # management port down rules
-    down ip {{ '-4' if prefix | ipv4 else '-6' }} route delete default via {{ MGMT_INTERFACE[(name, prefix)]['gwaddr'] }} dev eth0 table {{ vrf_table }}
-    down ip {{ '-4' if prefix | ipv4 else '-6' }} route delete {{ prefix | network }}/{{ prefix | prefixlen }} dev eth0 table {{ vrf_table }}
-    down ip {{ '-4' if prefix | ipv4 else '-6' }} rule delete from {{ prefix | ip }}/{{ '32' if prefix | ipv4 else '128' }} table {{ vrf_table }}
+    pre-down ip {{ '-4' if prefix | ipv4 else '-6' }} route delete default via {{ MGMT_INTERFACE[(name, prefix)]['gwaddr'] }} dev eth0 table {{ vrf_table }}
+    pre-down ip {{ '-4' if prefix | ipv4 else '-6' }} route delete {{ prefix | network }}/{{ prefix | prefixlen }} dev eth0 table {{ vrf_table }}
+    pre-down ip {{ '-4' if prefix | ipv4 else '-6' }} rule delete from {{ prefix | ip }}/{{ '32' if prefix | ipv4 else '128' }} table {{ vrf_table }}
 {% if (MGMT_VRF_CONFIG) and (MGMT_VRF_CONFIG['vrf_global']['mgmtVrfEnabled'] == "true") %}
     down cgdelete -g l3mdev:mgmt
 {% endif %}
 {% for route in MGMT_INTERFACE[(name, prefix)]['forced_mgmt_routes'] %}
-    down ip rule delete to {{ route }} table {{ vrf_table }}
+    pre-down ip rule delete to {{ route }} table {{ vrf_table }}
 {% endfor %}
 {# TODO: COPP policy type rules #}
 {% endfor %}

src/sonic-config-engine/tests/sample_output/interfaces

@@ -18,9 +18,9 @@ iface eth0 inet static
     up ip -4 route add 10.0.0.0/24 dev eth0 table default
     up ip -4 rule add from 10.0.0.100/32 table default
     # management port down rules
-    down ip -4 route delete default via 10.0.0.1 dev eth0 table default
-    down ip -4 route delete 10.0.0.0/24 dev eth0 table default
-    down ip -4 rule delete from 10.0.0.100/32 table default
+    pre-down ip -4 route delete default via 10.0.0.1 dev eth0 table default
+    pre-down ip -4 route delete 10.0.0.0/24 dev eth0 table default
+    pre-down ip -4 rule delete from 10.0.0.100/32 table default
 iface eth0 inet6 static
     address 2603:10e2:0:2902::8
     netmask 64
@@ -30,9 +30,9 @@ iface eth0 inet6 static
     up ip -6 route add 2603:10e2:0:2902::/64 dev eth0 table default
     up ip -6 rule add from 2603:10e2:0:2902::8/128 table default
     # management port down rules
-    down ip -6 route delete default via 2603:10e2:0:2902::1 dev eth0 table default
-    down ip -6 route delete 2603:10e2:0:2902::/64 dev eth0 table default
-    down ip -6 rule delete from 2603:10e2:0:2902::8/128 table default
+    pre-down ip -6 route delete default via 2603:10e2:0:2902::1 dev eth0 table default
+    pre-down ip -6 route delete 2603:10e2:0:2902::/64 dev eth0 table default
+    pre-down ip -6 rule delete from 2603:10e2:0:2902::8/128 table default
 #
 source /etc/network/interfaces.d/*
 #

src/sonic-config-engine/tests/sample_output/mvrf_interfaces

@@ -6,15 +6,15 @@
 auto mgmt
 iface mgmt
     vrf-table 5000
-# The loopback network interface
-auto lo
-iface lo inet loopback
 # The loopback network interface for mgmt VRF that is required for applications like NTP
     up ip link add lo-m type dummy
+    up ip link set dev lo-m master mgmt
     up ip addr add 127.0.0.1/8 dev lo-m
     up ip link set lo-m up
-    up ip link set dev lo-m master mgmt
-	down ip link delete dev lo-m
+    down ip link delete dev lo-m
+# The loopback network interface
+auto lo
+iface lo inet loopback
 
 # The management network interface
 auto eth0
@@ -30,9 +30,9 @@ iface eth0 inet static
     up cgcreate -g l3mdev:mgmt
     up cgset -r l3mdev.master-device=mgmt mgmt
     # management port down rules
-    down ip -4 route delete default via 10.0.0.1 dev eth0 table 5000
-    down ip -4 route delete 10.0.0.0/24 dev eth0 table 5000
-    down ip -4 rule delete from 10.0.0.100/32 table 5000
+    pre-down ip -4 route delete default via 10.0.0.1 dev eth0 table 5000
+    pre-down ip -4 route delete 10.0.0.0/24 dev eth0 table 5000
+    pre-down ip -4 rule delete from 10.0.0.100/32 table 5000
     down cgdelete -g l3mdev:mgmt
 iface eth0 inet6 static
     address 2603:10e2:0:2902::8
@@ -46,9 +46,9 @@ iface eth0 inet6 static
     up cgcreate -g l3mdev:mgmt
     up cgset -r l3mdev.master-device=mgmt mgmt
     # management port down rules
-    down ip -6 route delete default via 2603:10e2:0:2902::1 dev eth0 table 5000
-    down ip -6 route delete 2603:10e2:0:2902::/64 dev eth0 table 5000
-    down ip -6 rule delete from 2603:10e2:0:2902::8/128 table 5000
+    pre-down ip -6 route delete default via 2603:10e2:0:2902::1 dev eth0 table 5000
+    pre-down ip -6 route delete 2603:10e2:0:2902::/64 dev eth0 table 5000
+    pre-down ip -6 rule delete from 2603:10e2:0:2902::8/128 table 5000
     down cgdelete -g l3mdev:mgmt
 #
 source /etc/network/interfaces.d/*