[DHCP_RELAY] Updated wait_for_intf.sh to wait for ipv6 global and link local addr (#12273)

- Why I did it
Fixes #11431

- How I did it
dhcp6relay binds to ipv6 addresses configured on these vlan interfaces
Thus check if they are ready before launching dhcp6relay

- How to verify it
Unit Tests
Tested on a live device

Signed-off-by: Vivek Reddy Karri <vkarri@nvidia.com>

dockers/docker-dhcp-relay/wait_for_intf.sh.j2

@@ -21,8 +21,28 @@ function wait_until_iface_ready
     echo "Interface ${IFACE_NAME} is ready!"
 }
 
+function check_for_ipv6_link_local
+{
+    IFACE_NAME=$1
+    echo "Waiting until interface ${IFACE_NAME} has a link-local ipv6 address configured...."
+
+    # Status of link local address is not populated in STATE_DB
+    while true; do
+        HAS_LL=$(ip -6 addr show ${IFACE_NAME} scope link 2> /dev/null)
+        RC=$?
+        if [[ ${RC} == "0" ]] && [[ ! -z ${HAS_LL} ]]; then
+            break
+        fi
+
+        sleep 1
+    done
+
+    echo "Link-Local address is configured on ${IFACE_NAME}"
+}
 
 # Wait for all interfaces with IPv4 addresses to be up and ready
+# dhcp6relay binds to ipv6 addresses configured on these vlan ifaces
+# Thus check if they are ready before launching dhcp6relay
 {% for (name, prefix) in INTERFACE|pfx_filter %}
 {% if prefix | ipv4 %}
 wait_until_iface_ready {{ name }} {{ prefix }}
@@ -32,6 +52,12 @@ wait_until_iface_ready {{ name }} {{ prefix }}
 {% if prefix | ipv4 %}
 wait_until_iface_ready {{ name }} {{ prefix }}
 {% endif %}
+{% if prefix | ipv6 %}
+{% if DHCP_RELAY and name in DHCP_RELAY %}
+wait_until_iface_ready {{ name }} {{ prefix }}
+check_for_ipv6_link_local {{ name }}
+{% endif %}
+{% endif %}
 {% endfor %}
 {% for (name, prefix) in PORTCHANNEL_INTERFACE|pfx_filter %}
 {% if prefix | ipv4 %}

src/sonic-config-engine/tests/dhcp-relay-sample.json

@@ -0,0 +1,5 @@
+{
+    "VLAN_INTERFACE": {
+        "Vlan1000|fc02:2000::2/24": {}
+    }
+}

src/sonic-config-engine/tests/sample_output/py2/wait_for_intf.sh

@@ -21,10 +21,32 @@ function wait_until_iface_ready
     echo "Interface ${IFACE_NAME} is ready!"
 }
 
+function check_for_ipv6_link_local
+{
+    IFACE_NAME=$1
+    echo "Waiting until interface ${IFACE_NAME} has a link-local ipv6 address configured...."
+
+    # Status of link local address is not populated in STATE_DB
+    while true; do
+        HAS_LL=$(ip -6 addr show ${IFACE_NAME} scope link 2> /dev/null)
+        RC=$?
+        if [[ ${RC} == "0" ]] && [[ ! -z ${HAS_LL} ]]; then
+            break
+        fi
+
+        sleep 1
+    done
+
+    echo "Link-Local address is configured on ${IFACE_NAME}"
+}
 
 # Wait for all interfaces with IPv4 addresses to be up and ready
+# dhcp6relay binds to ipv6 addresses configured on these vlan ifaces
+# Thus check if they are ready before launching dhcp6relay
 wait_until_iface_ready Vlan2000 192.168.200.1/27
 wait_until_iface_ready Vlan1000 192.168.0.1/27
+wait_until_iface_ready Vlan1000 fc02:2000::2/24
+check_for_ipv6_link_local Vlan1000
 wait_until_iface_ready PortChannel02 10.0.0.58/31
 wait_until_iface_ready PortChannel03 10.0.0.60/31
 wait_until_iface_ready PortChannel04 10.0.0.62/31

src/sonic-config-engine/tests/sample_output/py3/wait_for_intf.sh

@@ -21,8 +21,30 @@ function wait_until_iface_ready
     echo "Interface ${IFACE_NAME} is ready!"
 }
 
+function check_for_ipv6_link_local
+{
+    IFACE_NAME=$1
+    echo "Waiting until interface ${IFACE_NAME} has a link-local ipv6 address configured...."
+
+    # Status of link local address is not populated in STATE_DB
+    while true; do
+        HAS_LL=$(ip -6 addr show ${IFACE_NAME} scope link 2> /dev/null)
+        RC=$?
+        if [[ ${RC} == "0" ]] && [[ ! -z ${HAS_LL} ]]; then
+            break
+        fi
+
+        sleep 1
+    done
+
+    echo "Link-Local address is configured on ${IFACE_NAME}"
+}
 
 # Wait for all interfaces with IPv4 addresses to be up and ready
+# dhcp6relay binds to ipv6 addresses configured on these vlan ifaces
+# Thus check if they are ready before launching dhcp6relay
+wait_until_iface_ready Vlan1000 fc02:2000::2/24
+check_for_ipv6_link_local Vlan1000
 wait_until_iface_ready Vlan1000 192.168.0.1/27
 wait_until_iface_ready Vlan2000 192.168.200.1/27
 wait_until_iface_ready PortChannel01 10.0.0.56/31

src/sonic-config-engine/tests/test_j2files.py

@@ -97,8 +97,9 @@ class TestJ2Files(TestCase):
 
     def test_dhcp_relay(self):
         # Test generation of wait_for_intf.sh
+        dhc_sample_data = os.path.join(self.test_dir, "dhcp-relay-sample.json")
         template_path = os.path.join(self.test_dir, '..', '..', '..', 'dockers', 'docker-dhcp-relay', 'wait_for_intf.sh.j2')
-        argument = '-m ' + self.t0_minigraph + ' -p ' + self.t0_port_config + ' -t ' + template_path + ' > ' + self.output_file
+        argument = '-m ' + self.t0_minigraph + ' -j ' + dhc_sample_data + ' -p ' + self.t0_port_config + ' -t ' + template_path + ' > ' + self.output_file
         self.run_script(argument)
         self.assertTrue(utils.cmp(os.path.join(self.test_dir, 'sample_output', utils.PYvX_DIR, 'wait_for_intf.sh'), self.output_file))