[l2-preset]: Add all dual ToR required fields (sonic-net#7318)

- Add peer_switch field to DEVICE_METADATA table
- In PORT table:
   - Set used ports to admin status up
   - Set mux_cable to true for downlinks in use
- In MUX_CABLE table:
   - Only add entry if the downlink is in use

Signed-off-by: Lawrence Lee <lawlee@microsoft.com>

src/sonic-config-engine/config_samples.py

@@ -1,5 +1,6 @@
 import sys
 
+from collections import defaultdict
 from ipaddress import ip_interface
 from natsort import natsorted
 
@@ -37,7 +38,7 @@ def generate_t1_sample_config(data):
                 'keepalive': '60'
                 }
         port_count += 1
-    return data;
+    return data
 
 def generate_empty_config(data):
     new_data = {'DEVICE_METADATA': data['DEVICE_METADATA']}
@@ -47,49 +48,79 @@ def generate_empty_config(data):
         new_data['DEVICE_METADATA']['localhost']['type'] = 'LeafRouter'
     return new_data
 
+def generate_global_dualtor_tables():
+    data = defaultdict(lambda: defaultdict(dict))
+    data['LOOPBACK_INTERFACE'] = {
+                                    'Loopback2': {},
+                                    'Loopback2|3.3.3.3': {}
+                                    }
+    data['MUX_CABLE'] = {}
+    data['PEER_SWITCH'] = {
+                            "peer_switch_hostname": {
+                                "address_ipv4": "1.1.1.1"
+                            }
+                            }
+    data['TUNNEL'] = {
+                        "MuxTunnel0": {
+                            "dscp_mode": "uniform",
+                            "dst_ip": "2.2.2.2",
+                            "ecn_mode": "copy_from_outer",
+                            "encap_ecn_mode": "standard",
+                            "ttl_mode": "pipe",
+                            "tunnel_type": "IPINIP"
+                        }
+                    }
+    return data
+
 def generate_l2_config(data):
+    # Check if dual ToR configs are needed
     if 'is_dualtor' in data and data['is_dualtor']:
         is_dualtor = True
         data.pop('is_dualtor')
     else:
         is_dualtor = False
+
+    if 'uplinks' in data:
+        uplinks = data['uplinks']
+        data.pop('uplinks')
+
+    if 'downlinks' in data:
+        downlinks = data['downlinks']
+        data.pop('downlinks')
+
+    # VLAN initial data
     data['VLAN'] = {'Vlan1000': {'vlanid': '1000'}}
     data['VLAN_MEMBER'] = {}
+
     if is_dualtor:
         data['DEVICE_METADATA']['localhost']['subtype'] = 'DualToR'
-        data['LOOPBACK_INTERFACE'] = {
-                                        'Loopback2': {},
-                                        'Loopback2|3.3.3.3': {}
-                                     }
-        data['MUX_CABLE'] = {}
-        data['PEER_SWITCH'] = {
-                                "peer_switch_hostname": {
-                                    "address_ipv4": "1.1.1.1"
-                                }
-                              }
-        data['TUNNEL'] = {
-                            "MuxTunnel0": {
-                                "dscp_mode": "uniform",
-                                "dst_ip": "2.2.2.2",
-                                "ecn_mode": "copy_from_outer",
-                                "encap_ecn_mode": "standard",
-                                "ttl_mode": "pipe",
-                                "tunnel_type": "IPINIP"
-                            }
-                         }
+        data['DEVICE_METADATA']['localhost']['peer_switch'] = 'peer_switch_hostname'
+        data.update(generate_global_dualtor_tables())
 
         server_ipv4_base = ip_interface(UNICODE_TYPE('192.168.0.1/32'))
         server_ipv6_base = ip_interface(UNICODE_TYPE('fc02:1000::1/128'))
-    for i, port in enumerate(natsorted(data['PORT'])):
-        data['PORT'][port].setdefault('admin_status', 'up')
-        data['VLAN_MEMBER']['Vlan1000|{}'.format(port)] = {'tagging_mode': 'untagged'}
+        server_offset = 1
+    for port in natsorted(data['PORT']):
         if is_dualtor:
-            mux_cable_entry = {
-                'server_ipv4': str(server_ipv4_base + i),
-                'server_ipv6': str(server_ipv6_base + i),
-                'state': 'auto'
-            }
-            data['MUX_CABLE'][port] = mux_cable_entry
+            # Ports in use should be admin up, unused ports default to admin down
+            if port in downlinks or port in uplinks:
+                data['PORT'][port].setdefault('admin_status', 'up')
+                data['VLAN_MEMBER']['Vlan1000|{}'.format(port)] = {'tagging_mode': 'untagged'}
+
+            # Downlinks (connected to mux cable) need a MUX_CABLE entry
+            # as well as the `mux_cable` field in the PORT table
+            if port in downlinks:
+                mux_cable_entry = {
+                    'server_ipv4': str(server_ipv4_base + server_offset),
+                    'server_ipv6': str(server_ipv6_base + server_offset),
+                    'state': 'auto'
+                }
+                server_offset += 1
+                data['MUX_CABLE'][port] = mux_cable_entry
+                data['PORT'][port]['mux_cable'] = 'true'
+        else:
+            data['PORT'][port].setdefault('admin_status', 'up')
+            data['VLAN_MEMBER']['Vlan1000|{}'.format(port)] = {'tagging_mode': 'untagged'}
     return data
 
 _sample_generators = {