[yang][smartswitch] Add YANG model for MID_PLANE_BRIDGE and DPU tables. (#17311)

- Why I did it
Add the YANG model according to Smart Switch IP address assignment HDL.

- How I did it
Implement new YANG model containers.

- How to verify it
Run YANG model unit tests. The changes add new unit tests to cover new functionality.

src/sonic-yang-models/doc/Configuration.md

@@ -2718,6 +2718,37 @@ The FIPS table introduces FIPS  configuration.
     }
 }
 ```
+### MID_PLANE_BRIDGE"
+
+The MID_PLANE_BRIDGE" table introduces the configuration for the midplane bridge interface for Smart Switch.
+
+```json
+{
+    "MID_PLANE_BRIDGE": {
+        "GLOBAL" : {
+            "bridge": "bridge_midplane",
+            "ip_prefix": "169.254.200.254/24"
+        }
+    }
+}
+```
+
+### DPUS
+
+The DPUS table introduces the information on the DPUs (Data Processing Unit) available on the platform.
+
+```json
+{
+    "DPUS": {
+        "dpu0": {
+            "midplane_interface": "dpu0"
+        },
+        "dpu1": {
+            "midplane_interface": "dpu1"
+        }
+    }
+}
+```
 
 #### 5.2.3 Update value directly in db memory
 

src/sonic-yang-models/setup.py

@@ -197,7 +197,8 @@ setup(
                          './yang-models/sonic-static-route.yang',
                          './yang-models/sonic-system-port.yang',
                          './yang-models/sonic-macsec.yang',
-                         './yang-models/sonic-bgp-sentinel.yang']),
+                         './yang-models/sonic-bgp-sentinel.yang',
+                         './yang-models/sonic-smart-switch.yang',]),
         ('cvlyang-models', ['./cvlyang-models/sonic-acl.yang',
                          './cvlyang-models/sonic-bgp-common.yang',
                          './cvlyang-models/sonic-bgp-global.yang',

src/sonic-yang-models/tests/files/sample_config_db.json

@@ -2558,6 +2558,20 @@
                 "bank": "1",
                 "link": "PortChannel2"
             }
+        },
+        "MID_PLANE_BRIDGE": {
+            "GLOBAL" : {
+                "bridge": "bridge_midplane",
+                "ip_prefix": "169.254.200.254/24"
+            }
+        },
+        "DPUS": {
+            "dpu0": {
+                "midplane_interface": "dpu0"
+            },
+            "dpu1": {
+                "midplane_interface": "dpu1"
+            }
         }
     },
     "SAMPLE_CONFIG_DB_UNKNOWN": {

src/sonic-yang-models/tests/yang_model_tests/tests/smart-switch.json

@@ -0,0 +1,9 @@
+{
+    "SMART_SWITCH_MID_PLANE_BRIDGE_WITH_DPU_TEST" : {
+        "desc": "Valid configuration in MID_PLANE_BRIDGE and DPUS tables."
+    },
+    "SMART_SWITCH_DPU_NAME_TEST" : {
+        "desc": "DPU name validation.",
+        "eStr": "does not satisfy the constraint"
+    }
+}

src/sonic-yang-models/tests/yang_model_tests/tests_config/smart-switch.json

@@ -0,0 +1,40 @@
+{
+    "SMART_SWITCH_MID_PLANE_BRIDGE_WITH_DPU_TEST": {
+        "sonic-smart-switch:sonic-smart-switch": {
+            "sonic-smart-switch:MID_PLANE_BRIDGE": {
+                "GLOBAL": {
+                    "bridge": "bridge_midplane",
+                    "ip_prefix": "169.254.200.254/24"
+                }
+            },
+            "sonic-smart-switch:DPUS": {
+                "DPUS_LIST": [
+                    {
+                        "dpu_name": "dpu0",
+                        "midplane_interface": "dpu0"
+                    },
+                    {
+                        "dpu_name": "dpu1",
+                        "midplane_interface": "dpu1"
+                    }
+                ]
+            }
+        }
+    },
+    "SMART_SWITCH_DPU_NAME_TEST": {
+        "sonic-smart-switch:sonic-smart-switch": {
+            "sonic-smart-switch:DPUS": {
+                "DPUS_LIST": [
+                    {
+                        "dpu_name": "dpu0",
+                        "midplane_interface": "dpuX"
+                    },
+                    {
+                        "dpu_name": "dpu1",
+                        "midplane_interface": "dpu0"
+                    }
+                ]
+            }
+        }
+    }
+}

src/sonic-yang-models/yang-models/sonic-device_metadata.yang

@@ -157,7 +157,7 @@ module sonic-device_metadata {
 
                 leaf subtype {
                     type string {
-                        pattern "DualToR";
+                        pattern "DualToR|SmartSwitch";
                     }
                 }
 

src/sonic-yang-models/yang-models/sonic-smart-switch.yang

@@ -0,0 +1,80 @@
+module sonic-smart-switch {
+
+    yang-version 1.1;
+
+	namespace "http://github.com/sonic-net/sonic-smart-switch";
+	prefix smart-switch;
+
+	import ietf-inet-types {
+		prefix inet;
+	}
+
+    import sonic-types {
+        prefix stypes;
+    }
+
+	import sonic-port {
+        prefix port;
+    }
+
+	description "Smart Switch yang Module for SONiC OS";
+
+	revision 2023-10-17 {
+		description "First Revision";
+	}
+
+	container sonic-smart-switch {
+
+		container MID_PLANE_BRIDGE {
+
+			description "MID_PLANE_BRIDGE part of config_db.json";
+
+			container GLOBAL {
+				leaf bridge {
+					type string {
+						pattern "bridge_midplane";
+					}
+					description "Name of the midplane bridge";
+
+					must "(current()/../ip_prefix)";
+				}
+
+				leaf ip_prefix {
+					type stypes:sonic-ip4-prefix;
+					description "IP prefix of the midplane bridge";
+				}
+			}
+			/* end of container GLOBAL */
+		}
+		/* end of container MID_PLANE_BRIDGE */
+
+		container DPUS {
+			description "DPUS part of config_db.json";
+
+			list DPUS_LIST {
+				key "dpu_name";
+
+				leaf dpu_name {
+					description "Name of the DPU";
+					type string {
+						pattern "dpu[0-9]+";
+					}
+				}
+
+				leaf midplane_interface {
+					description "Name of the interface that represents DPU";
+
+					type string {
+						pattern "dpu[0-9]+";
+					}
+
+					must "(current() = current()/../dpu_name)";
+				}
+			}
+			/* end of container DPUS_LIST */
+		}
+		/* end of container DPUS */
+	}
+	/* end of container sonic-smart-switch */
+}
+/* end of module sonic-smart-switch */