Fix tagged VlanInterface if attached to multiple vlan as untagged member (#8927)

#### Why I did it
Fix several bugs:
1. If one vlan member belongs to multiple vlans, and if any of the vlans is "Tagged" type, we respect the tagged type
2. If one vlan member belongs to multiple vlans, and all of the vlans have no "Tagged" type, we override it to be a tagged member
3. make sure `vlantype_name` is assigned correctly in each iteration

#### How to verify it
1. Test the command line to parse a minigraph and make sure the output does not change.
```
./sonic-cfggen -m minigraph.mlnx20.xml
```
The minigraph is for HwSKU Mellanox-SN2700-D40C8S8.

2. Test on a DUT with HwSKU Mellanox-SN2700-D40C8S8
```
sudo config load_minigraph
show vlan brief
```
Checked the "Port Tagging" column in the output.

src/sonic-config-engine/minigraph.py

@@ -536,28 +536,36 @@ def parse_dpg(dpg, hname):
         vlan_members = {}
         vlan_member_list = {}
         dhcp_relay_table = {}
-        vlantype_name = ""
+        # Dict: vlan member (port/PortChannel) -> set of VlanID, in which the member if an untagged vlan member
-        intf_vlan_mbr = defaultdict(list)
+        untagged_vlan_mbr = defaultdict(set)
         for vintf in vlanintfs.findall(str(QName(ns, "VlanInterface"))):
             vlanid = vintf.find(str(QName(ns, "VlanID"))).text
+            vlantype = vintf.find(str(QName(ns, "Type")))
+            if vlantype is None:
+                vlantype_name = ""
+            else:
+                vlantype_name = vlantype.text
             vintfmbr = vintf.find(str(QName(ns, "AttachTo"))).text
             vmbr_list = vintfmbr.split(';')
-            for i, member in enumerate(vmbr_list):
+            if vlantype_name != "Tagged":
-                intf_vlan_mbr[member].append(vlanid)
+                for member in vmbr_list:
+                    untagged_vlan_mbr[member].add(vlanid)
         for vintf in vlanintfs.findall(str(QName(ns, "VlanInterface"))):
             vintfname = vintf.find(str(QName(ns, "Name"))).text
             vlanid = vintf.find(str(QName(ns, "VlanID"))).text
             vintfmbr = vintf.find(str(QName(ns, "AttachTo"))).text
             vlantype = vintf.find(str(QName(ns, "Type")))
-            if vlantype != None:
+            if vlantype is None:
-                vlantype_name = vintf.find(str(QName(ns, "Type"))).text
+                vlantype_name = ""
+            else:
+                vlantype_name = vlantype.text
             vmbr_list = vintfmbr.split(';')
             for i, member in enumerate(vmbr_list):
                 vmbr_list[i] = port_alias_map.get(member, member)
                 sonic_vlan_member_name = "Vlan%s" % (vlanid)
                 if vlantype_name == "Tagged":
                     vlan_members[(sonic_vlan_member_name, vmbr_list[i])] = {'tagging_mode': 'tagged'}
-                elif len(intf_vlan_mbr[member]) > 1:
+                elif len(untagged_vlan_mbr[member]) > 1:
                     vlan_members[(sonic_vlan_member_name, vmbr_list[i])] = {'tagging_mode': 'tagged'}
                 else:
                     vlan_members[(sonic_vlan_member_name, vmbr_list[i])] = {'tagging_mode': 'untagged'}

src/sonic-config-engine/tests/sample-graph-resource-type.xml

@@ -190,6 +190,14 @@
           <Tag>1000</Tag>
           <Subnets>192.168.0.0/27</Subnets>
         </VlanInterface>
+        <VlanInterface>
+          <Name>ab4</Name>
+          <AttachTo>fortyGigE0/8</AttachTo>
+          <DhcpRelays>192.0.0.1;192.0.0.2</DhcpRelays>
+          <VlanID>1001</VlanID>
+          <Tag>1001</Tag>
+          <Subnets>192.168.0.32/27</Subnets>
+        </VlanInterface>
         <VlanInterface>
           <Name>kk1</Name>
           <AttachTo>fortyGigE0/12</AttachTo>
@@ -205,6 +213,7 @@
           <DhcpRelays>192.0.0.1;192.0.0.2</DhcpRelays>
           <VlanID>2000</VlanID>
           <Tag>2000</Tag>
+          <Type>Tagged</Type>
           <Subnets>192.168.0.240/27</Subnets>
         </VlanInterface>
         <VlanInterface>

src/sonic-config-engine/tests/sample-graph-subintf.xml

@@ -208,6 +208,14 @@
           <Tag>1000</Tag>
           <Subnets>192.168.0.0/27</Subnets>
         </VlanInterface>
+        <VlanInterface>
+          <Name>ab4</Name>
+          <AttachTo>fortyGigE0/8</AttachTo>
+          <DhcpRelays>192.0.0.1;192.0.0.2</DhcpRelays>
+          <VlanID>1001</VlanID>
+          <Tag>1001</Tag>
+          <Subnets>192.168.0.32/27</Subnets>
+        </VlanInterface>
         <VlanInterface>
           <Name>kk1</Name>
           <AttachTo>fortyGigE0/12</AttachTo>

src/sonic-config-engine/tests/simple-sample-graph.xml

@@ -190,6 +190,14 @@
           <Tag>1000</Tag>
           <Subnets>192.168.0.0/27</Subnets>
         </VlanInterface>
+        <VlanInterface>
+          <Name>ab4</Name>
+          <AttachTo>fortyGigE0/8</AttachTo>
+          <DhcpRelays>192.0.0.1;192.0.0.2</DhcpRelays>
+          <VlanID>1001</VlanID>
+          <Tag>1001</Tag>
+          <Subnets>192.168.0.32/27</Subnets>
+        </VlanInterface>
         <VlanInterface>
           <Name>kk1</Name>
           <AttachTo>fortyGigE0/12</AttachTo>
@@ -205,6 +213,7 @@
           <DhcpRelays>192.0.0.1;192.0.0.2</DhcpRelays>
           <VlanID>2000</VlanID>
           <Tag>2000</Tag>
+          <Type>Tagged</Type>
           <Subnets>192.168.0.240/27</Subnets>
         </VlanInterface>
         <VlanInterface>

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

@@ -151,6 +151,7 @@ class TestCfgGen(TestCase):
                 utils.to_dict(output.strip()),
                 utils.to_dict(
                     '{\n    "Vlan1000|Ethernet8": {\n        "tagging_mode": "tagged"\n    },'
+                    ' \n    "Vlan1001|Ethernet8": {\n        "tagging_mode": "tagged"\n    },'
                     ' \n    "Vlan2000|Ethernet12": {\n        "tagging_mode": "tagged"\n    },'
                     ' \n    "Vlan2001|Ethernet12": {\n        "tagging_mode": "tagged"\n    },'
                     ' \n    "Vlan2020|Ethernet12": {\n        "tagging_mode": "tagged"\n    }\n}'
@@ -160,9 +161,10 @@ class TestCfgGen(TestCase):
             self.assertEqual(
                 utils.to_dict(output.strip()),
                 utils.to_dict(
-                    '{\n    "Vlan1000|Ethernet8": {\n        "tagging_mode": "untagged"\n    },'
+                    '{\n    "Vlan1000|Ethernet8": {\n        "tagging_mode": "tagged"\n    },'
+                    ' \n    "Vlan1001|Ethernet8": {\n        "tagging_mode": "tagged"\n    },'
                     ' \n    "Vlan2000|Ethernet12": {\n        "tagging_mode": "tagged"\n    },'
-                    ' \n    "Vlan2001|Ethernet12": {\n        "tagging_mode": "tagged"\n    },'
+                    ' \n    "Vlan2001|Ethernet12": {\n        "tagging_mode": "untagged"\n    },'
                     ' \n    "Vlan2020|Ethernet12": {\n        "tagging_mode": "tagged"\n    }\n}'
                 )
             )
@@ -249,6 +251,7 @@ class TestCfgGen(TestCase):
             utils.to_dict(output.strip()),
             utils.to_dict(
                 "{'Vlan1000': {'alias': 'ab1', 'dhcp_servers': ['192.0.0.1', '192.0.0.2'], 'vlanid': '1000'}, "
+                "'Vlan1001': {'alias': 'ab4', 'dhcp_servers': ['192.0.0.1', '192.0.0.2'], 'vlanid': '1001'},"
                 "'Vlan2001': {'alias': 'ab3', 'dhcp_servers': ['192.0.0.1', '192.0.0.2'], 'vlanid': '2001'},"
                 "'Vlan2000': {'alias': 'ab2', 'dhcp_servers': ['192.0.0.1', '192.0.0.2'], 'vlanid': '2000'},"
                 "'Vlan2020': {'alias': 'kk1', 'dhcp_servers': ['192.0.0.1', '192.0.0.2'], 'vlanid': '2020'}}"
@@ -265,6 +268,7 @@ class TestCfgGen(TestCase):
                 utils.to_dict(output.strip()),
                 utils.to_dict(
                     "{('Vlan2000', 'Ethernet12'): {'tagging_mode': 'tagged'}, "
+                    "('Vlan1001', 'Ethernet8'): {'tagging_mode': 'tagged'}, "
                     "('Vlan1000', 'Ethernet8'): {'tagging_mode': 'tagged'}, "
                     "('Vlan2020', 'Ethernet12'): {'tagging_mode': 'tagged'}, "
                     "('Vlan2001', 'Ethernet12'): {'tagging_mode': 'tagged'}}"
@@ -275,9 +279,10 @@ class TestCfgGen(TestCase):
                 utils.to_dict(output.strip()),
                 utils.to_dict(
                     "{('Vlan2000', 'Ethernet12'): {'tagging_mode': 'tagged'}, "
-                    "('Vlan1000', 'Ethernet8'): {'tagging_mode': 'untagged'}, "
+                    "('Vlan1000', 'Ethernet8'): {'tagging_mode': 'tagged'}, "
+                    "('Vlan1001', 'Ethernet8'): {'tagging_mode': 'tagged'}, "
                     "('Vlan2020', 'Ethernet12'): {'tagging_mode': 'tagged'}, "
-                    "('Vlan2001', 'Ethernet12'): {'tagging_mode': 'tagged'}}"
+                    "('Vlan2001', 'Ethernet12'): {'tagging_mode': 'untagged'}}"
                 )
             )
 
@@ -704,6 +709,9 @@ class TestCfgGen(TestCase):
     def test_minigraph_sub_port_interfaces(self, check_stderr=True):
         self.verify_sub_intf(check_stderr=check_stderr)
 
+    def test_minigraph_sub_port_intf_resource_type_non_backend_tor(self, check_stderr=True):
+        self.verify_sub_intf_non_backend_tor(graph_file=self.sample_resource_graph, check_stderr=check_stderr)
+
     def test_minigraph_sub_port_intf_resource_type(self, check_stderr=True):
         self.verify_sub_intf(graph_file=self.sample_resource_graph, check_stderr=check_stderr)
 
@@ -737,6 +745,14 @@ class TestCfgGen(TestCase):
         output = self.run_script(argument)
         self.assertEqual(output.strip(), "{}")
 
+    def verify_sub_intf_non_backend_tor(self, **kwargs):
+        graph_file = kwargs.get('graph_file', self.sample_graph_simple)
+
+        # All the other tables stay unchanged
+        self.test_var_json_data(graph_file=graph_file)
+        self.test_minigraph_vlans(graph_file=graph_file)
+        self.test_minigraph_vlan_members(graph_file=graph_file)
+
     def verify_sub_intf(self, **kwargs):
         graph_file = kwargs.get('graph_file', self.sample_graph_simple)
         check_stderr = kwargs.get('check_stderr', True)