[yang]Add FG-ECMP yang model

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

@@ -26,6 +26,9 @@ Table of Contents
          * [Device Metadata](#device-metadata)  
          * [Device neighbor metada](#device-neighbor-metada)  
          * [DSCP_TO_TC_MAP](#dscp_to_tc_map)  
+         * [FG_NHG](#fg_nhg)  
+         * [FG_NHG_MEMBER](#fg_nhg_member)  
+         * [FG_NHG_PREFIX](#fg_nhg_prefix)  
          * [FLEX_COUNTER_TABLE](#flex_counter_table)  
          * [Hash](#hash)  
          * [KDUMP](#kdump)  
@@ -892,6 +895,57 @@ instance is supported in SONiC.
 
 ```
 
+### FG_NHG
+
+The FG_NHG table provides information on Next Hop Groups, including a specified Hash Bucket Size (bucket_size) and match mode for each group.
+
+```
+"FG_NHG": {
+    "fgnhg_v4": {
+        "bucket_size": "120",
+        "match_mode": "nexthop-based"
+    },
+    "fgnhg_v6": {
+        "bucket_size": "120",
+        "match_mode": "nexthop-based"
+    }
+}
+```
+
+### FG_NHG_MEMBER
+
+The FG_NHG_MEMBER table provides information about the members of a next hop group, including the group name (FG_NHG), the index at which redistribution is performed (bank), and the link associated with the next-hop-ip (link).
+
+```
+"FG_NHG_MEMBER": {
+    "200.200.200.4": {
+        "FG_NHG": "fgnhg_v4",
+        "bank": "0",
+        "link": "Ethernet8"
+    },
+    "200.200.200.5": {
+        "FG_NHG": "fgnhg_v4",
+        "bank": "1",
+        "link": "Ethernet12"
+    }
+}
+```
+
+### FG_NHG_PREFIX
+
+The FG_NHG_PREFIX table provides the FG_NHG_PREFIX for which FG behavior is desired, and Fine Grained next-hop group name.
+
+```
+"FG_NHG_PREFIX": {
+    "100.50.25.12/32": {
+	    "FG_NHG": "fgnhg_v4"
+	},
+    "fc:05::/128": {
+	    "FG_NHG": "fgnhg_v6"
+	}
+}
+```
+
 
 ### MPLS_TC_TO_TC_MAP
 ```

src/sonic-yang-models/setup.py

@@ -116,6 +116,7 @@ def run(self):
                          './yang-models/sonic-events-syncd.yang',
                          './yang-models/sonic-extension.yang',
                          './yang-models/sonic-flex_counter.yang',
+                         './yang-models/sonic-fine-grained-ecmp.yang', 
                          './yang-models/sonic-feature.yang',
                          './yang-models/sonic-hash.yang',
                          './yang-models/sonic-system-defaults.yang',
@@ -203,6 +204,7 @@ def run(self):
                          './cvlyang-models/sonic-extension.yang',
                          './cvlyang-models/sonic-flex_counter.yang',
                          './cvlyang-models/sonic-feature.yang',
+                         './cvlyang-models/sonic-fine-grained-ecmp.yang',
                          './cvlyang-models/sonic-hash.yang',
                          './cvlyang-models/sonic-system-defaults.yang',
                          './cvlyang-models/sonic-interface.yang',

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

@@ -2273,6 +2273,46 @@
                "vni": "10",
                "guid":"guid-vnet1"
              }
+        },
+        "FG_NHG": {
+            "nhg1": {
+                "bucket_size": "16",
+                "match_mode": "nexthop-based"
+            },
+            "nhg2": {
+                "bucket_size": "32",
+                "match_mode": "route-based"
+            }
+        },
+        "FG_NHG_PREFIX": {
+            "10.0.0.0/24": {
+                "FG_NHG": "nhg1"
+            },
+            "192.168.0.0/16": {
+                "FG_NHG": "nhg2"
+            }
+        },
+        "FG_NHG_MEMBER": {
+            "192.168.1.1": {
+                "FG_NHG": "nhg1",
+                "bank": "0",
+                "link": "Ethernet1"
+            },
+            "192.168.1.2": {
+                "FG_NHG": "nhg1",
+                "bank": "0",
+                "link": "Ethernet2"
+            },
+            "10.0.0.1": {
+                "FG_NHG": "nhg2",
+                "bank": "1",
+                "link": "PortChannel42"
+            },
+            "10.0.0.2": {
+                "FG_NHG": "nhg2",
+                "bank": "1",
+                "link": "PortChannel2"
+            }
         }
     },
     "SAMPLE_CONFIG_DB_UNKNOWN": {

src/sonic-yang-models/tests/yang_model_tests/tests/fine-grained-ecmp.json

@@ -0,0 +1,59 @@
+{
+    "FG_NHG_TEST": {
+        "desc": "Fine-grained ECMP next-hop group configuration in FG_NHG_LIST table."
+    },
+    "FG_NHG_PREFIX_TEST": {
+        "desc": "Fine-grained ECMP prefix configuration in FG_NHG_PREFIX_LIST table."
+    },
+    "FG_NHG_MEMBER_TEST": {
+        "desc": "Fine-grained ECMP next-hop member configuration in FG_NHG_MEMBER_LIST table."
+    },
+    "FG_NHG_MEMBER_MULTI_LINK_TEST": {
+        "desc": "Fine-grained ECMP next-hop member configuration with multiple links in FG_NHG_MEMBER_LIST table."
+    },
+    "FG_NHG_TEST_DUPLICATE_NAME": {
+        "desc": "Fine-grained ECMP next-hop group configuration with duplicate name in FG_NHG_LIST table.",
+        "eStr": "Duplicated instance of \"FG_NHG_LIST\" list."
+    },
+    "FG_NHG_MEMBER_TEST_INVALID_IP": {
+        "desc": "Fine-grained ECMP next-hop member configuration with invalid IP value in FG_NHG_MEMBER_LIST table.",
+        "eStrKey": "InvalidValue",
+        "eStr": [
+            "next_hop_ip"
+        ]
+    },
+    "FG_NHG_PREFIX_TEST_INVALID_PREFIX": {
+        "desc": "Fine-grained ECMP prefix configuration with invalid prefix value in FG_NHG_PREFIX_LIST table.",
+        "eStrKey": "InvalidValue",
+        "eStr": [
+            "ip_prefix"
+        ]
+    },
+    "FG_NHG_MEMBER_TEST_INVALID_LINK": {
+        "desc": "Fine-grained ECMP next-hop member configuration with invalid link value in FG_NHG_MEMBER_LIST table.",
+        "eStrKey": "InvalidValue",
+        "eStr": [
+            "link"
+        ]
+    },
+    "FG_NHG_MEMBER_TEST_MISSING_FG_NHG_REF": {
+        "desc": "Fine-grained ECMP next-hop member configuration with missing FG_NHG reference in FG_NHG_MEMBER_LIST table.",
+        "eStr": "Missing required element \"FG_NHG\" in \"FG_NHG_MEMBER_LIST\". "
+    },
+    "FG_NHG_PREFIX_TEST_MISSING_FG_NHG_REF": {
+        "desc": "Fine-grained ECMP prefix configuration with missing FG_NHG reference in FG_NHG_PREFIX_LIST table.",
+        "eStr": "Missing required element \"FG_NHG\" in \"FG_NHG_PREFIX_LIST\". "
+    },
+    "FG_NHG_MEMBER_TEST_MISSING_BANK": {
+        "desc": "Fine-grained ECMP next-hop member configuration with missing bank in FG_NHG_MEMBER_LIST table.",
+        "eStr": "Missing required element \"bank\""
+    },
+    "FG_NHG_PREFIX_TEST_DUPLICATE_ENTRY": {
+        "desc": "Fine-grained ECMP prefix configuration with duplicate entry in FG_NHG_PREFIX_LIST table.",
+        "eStr": "Duplicated instance of \"FG_NHG_PREFIX_LIST\" list."
+    },
+    "FG_NHG_MEMBER_TEST_DUPLICATE_MEMBER": {
+        "desc": "Fine-grained ECMP next-hop member configuration with duplicate member in FG_NHG_MEMBER_LIST table.",
+        "eStr": "Duplicated instance of \"FG_NHG_MEMBER_LIST\" list."
+    }
+}