Added support for dynamic nexthop groups in Fine Grained Hashing Yang…

files/build_templates/default_manifest

@@ -52,9 +52,9 @@
         "show": [],
         "config": [],
         "clear": [],
-        "auto-generate-show": false,
-        "auto-generate-config": false,
-        "auto-generate-show-source-yang-modules": [],
-        "auto-generate-config-source-yang-modules": []
+        "auto-generate-show": true,
+        "auto-generate-config": true,
+        "auto-generate-show-source-yang-modules": [sonic-fine-grained-ecmp],
+        "auto-generate-config-source-yang-modules": [sonic-fine-grained-ecmp]
     }
 }

sonic-fine-grained-ecmp.yang

@@ -0,0 +1,197 @@
+module sonic-fine-grained-ecmp {
+
+    yang-version 1.1;
+
+    namespace "http://github.com/sonic-net/sonic-fine-grained-ecmp";
+    prefix sfgecmp;
+
+    import ietf-inet-types {
+        prefix inet;
+    }
+
+    import sonic-portchannel {
+        prefix lag;
+    }
+
+    import sonic-port {
+        prefix port;
+    }
+
+    import sonic-types {
+        prefix stypes;
+    }
+
+    organization
+        "SONiC";
+
+    contact
+        "SONiC";
+
+    description
+        "SONIC Fine Grained ECMP";
+
+    revision 2023-01-19 {
+        description "Initial revision.";
+    }
+
+    revision 2024-09-15 {
+        description "Added support for dynamic nexthop group.";
+    }
+
+    typedef match-mode-name {
+
+        type enumeration {
+
+            enum route-based {
+               description
+                 "Fine grained ecmp is used when the route prefix matches the FG_NHG_PREFIX prefix";
+            }
+
+            enum nexthop-based {
+               description
+                 "Fine grained ecmp is used when the nexthop IPs match the FG_NHG_MEMBER IPs";
+            }
+        }
+
+        description
+            "This enumeration type defines the method used to determine whether fine grained ecmp should be applied.";
+    }
+
+    typedef nhg-mode-name {
+        type enumeration {
+            enum static-nhg {
+               description
+                 "List of nexthops is statically configured in FG_NHG_MEMBER table.";
+            }
+
+            enum dynamic-nhg {
+               description
+                 "List of nexthops is dynamically derived from the route updates. FG_NHG_MEMBER table is not configured.";     
+            }
+        }
+
+        description
+            "This enumeration type defines whether the list of nexthops used for fine grained ecmp are statically configure or derived from route updates.";
+    }
+
+    container sonic-fine-grained-ecmp {
+
+        container FG_NHG {
+
+            description "FG_NHG part of config_db.json";
+
+            list FG_NHG_LIST{
+
+                key "name";
+
+                leaf name{
+                    type string;
+                    description "FG_NHG group name";
+                }
+
+                leaf bucket_size{
+                    type uint16;
+                    mandatory true;
+                    description "total hash bucket size desired, recommended value of Lowest Common Multiple of 1..{max # of next-hops}";
+                }
+
+                leaf match_mode{
+                    type match-mode-name;
+                    mandatory true;
+                    description " The filtering method used to identify when to use Fine Grained vs regular route handling. nexthop-based looks to next-hop IP to filter routes and uses fine grained ecmp when nexthop IPs matches FG_NHG_MEMBER IPs. route-based looks to prefix to filter routes, and uses fine grained ecmp when the route prefix matches the FG_NHG_PREFIX prefix.";
+                }
+
+                leaf nhg_mode{
+                    when "current()/../match_mode = 'route-based'";
+                    type nhg-mode-name;
+                    default 'static-nhg';
+                    description " static-nhg : List of nexthops needs to be statically configured in FG_NHG_MEMBER table. dynamic-nhg : List of nexthops will be dynamically derived from the route updates.";
+                }
+
+                leaf max_next_hops{
+                    when "current()/../nhg_mode = 'dynamic-nhg'";
+                    must "current() > 0" {
+                        error-message "max_next_hops needs to be a positive value in dynamic-nhg mode";
+                    }
+                    type uint16;
+                    description "Applicable only when nhg_mode = dynamic-nhg. Maximum number of nexthops that will be received in route updates for any of the prefixes that match FG_NHG_PREFIX for this FG_NHG.";
+                }
+
+            }
+             /* end of list FG_NHG_LIST */
+        }
+        /* end of container FG_NHG */
+
+        container FG_NHG_PREFIX{
+
+            description "FG_NHG_PREFIX part of config_db.json";
+
+            list FG_NHG_PREFIX_LIST{
+
+                key "ip_prefix";
+
+                leaf ip_prefix{
+                    type stypes:sonic-ip-prefix;
+                    description "FG_NHG_PREFIX for which FG behavior is
+                    desired";
+                }
+
+                leaf FG_NHG{
+                    type leafref {
+                        path "/sfgecmp:sonic-fine-grained-ecmp/sfgecmp:FG_NHG/sfgecmp:FG_NHG_LIST/sfgecmp:name";
+                    }
+                    mandatory true;
+                    description "Fine Grained next-hop group name";
+                }
+            }
+            /* end of list FG_NHG_PREFIX_LIST */
+        }
+        /* end of container FG_NHG_PREFIX */
+
+        container FG_NHG_MEMBER{
+
+            description "FG_NHG_MEMBER part of config_db.json";
+
+            list FG_NHG_MEMBER_LIST{
+
+                key "next_hop_ip";
+
+                leaf next_hop_ip{
+                    type inet:ip-address;
+                    description "FG_NHG next-hop-ip member associated
+                    with prefix";
+                }
+
+                leaf FG_NHG{
+                    type leafref {
+                        path "/sfgecmp:sonic-fine-grained-ecmp/sfgecmp:FG_NHG/sfgecmp:FG_NHG_LIST/sfgecmp:name";
+                }
+                    mandatory true;
+                    description "Fine Grained next-hop group name";
+                }
+
+                leaf bank{
+                    type uint16;
+                    mandatory true;
+                    description "An index which specifies a bank/group in which the redistribution is performed";
+                }
+
+                leaf link{
+                    type union {
+                        type leafref {
+                            path "/port:sonic-port/port:PORT/port:PORT_LIST/port:name";
+                        }
+                        type leafref {
+                            path "/lag:sonic-portchannel/lag:PORTCHANNEL/lag:PORTCHANNEL_LIST/lag:name";
+                        }
+                    }
+                    description "Link associated with next-hop-ip, if configured, enables next-hop withdrawal/addition per link's operational state changes";
+                }
+            }
+            /* end of list FG_NHG_MEMBER_LIST */
+        }
+        /* end of container FG_NHG_MEMBER */
+    }
+    /* end of container sonic-fine-grained-ecmp */
+}
+/* end of module sonic-fine-grained-ecmp */

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

@@ -1144,7 +1144,8 @@ IPV4 DHPC Server related configuration are defined in **DHCP_SERVER_IPV4**, **DH
 
 ### 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.
+The FG_NHG table provides information on Next Hop Groups, including a specified Hash Bucket Size (bucket_size), match mode for each group, nexthopgroup mode to distinguish between static vs
+dynamic nexthop configuration and an optional max-next-hops attribute for dynamic mode.
 
 ```
 "FG_NHG": {
@@ -1155,7 +1156,19 @@ The FG_NHG table provides information on Next Hop Groups, including a specified
     "fgnhg_v6": {
         "bucket_size": "120",
         "match_mode": "nexthop-based"
-    }
+    },
+    "dynamic_fgnhg_v4": {
+        "bucket_size": "120",
+        "match_mode": "nexthop-based",
+        "nhg_mode": "dynamic-nhg",
+        "max_next_hops": "6"
+    },
+    "dynamic_fgnhg_v6": {
+        "bucket_size": "120",
+        "match_mode": "nexthop-based",
+        "nhg_mode": "dynamic-nhg",
+        "max_next_hops": "6"
+    }    
 }
 ```
 
@@ -1189,7 +1202,13 @@ The FG_NHG_PREFIX table provides the FG_NHG_PREFIX for which FG behavior is desi
 	},
     "fc:05::/128": {
 	    "FG_NHG": "fgnhg_v6"
-	}
+	},
+    "200.175.150.125/32": {
+        "FG_NHG": "dynamic_fgnhg_v4"
+    },
+    "fd:06::/128": {
+        "FG_NHG": "dynamic_fgnhg_v6"
+	}    
 }
 ```
 

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

@@ -2726,6 +2726,12 @@
             "nhg2": {
                 "bucket_size": "32",
                 "match_mode": "route-based"
+            },
+            "nhg3": {
+                "bucket_size": "24",
+                "match_mode": "route-based",
+                "nhg_mode": "dynamic-nhg",
+                "max_next_hops": "6"
             }
         },
         "FG_NHG_PREFIX": {
@@ -2734,6 +2740,9 @@
             },
             "192.168.0.0/16": {
                 "FG_NHG": "nhg2"
+            },
+            "172.17.0.1/32": {
+                "FG_NHG": "nhg3"
             }
         },
         "FIPS":{

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

@@ -55,5 +55,18 @@
     "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."
+    },
+    "FG_NHG_TEST_DYNAMIC_NHG_MISSING_MAX_NEXT_HOPS": {
+        "desc": "Fine-grained ECMP Dynamic next-hop group configuration with missing max_next_hops in FG_NHG_LIST table.",
+        "eStrKey": "Mandatory",
+        "eStr": ["max_next_hops"]
+    },
+    "FG_NHG_TEST_DYNAMIC_NHG_MISSING_BUCKET_SIZE": {
+        "desc": "Fine-grained ECMP Dynamic next-hop group configuration with missing bucket_size in FG_NHG_LIST table.",
+        "eStr": "Missing required element \"bucket_size\" in \"FG_NHG_LIST\"."
+    },
+    "FG_NHG_TEST_DYNAMIC_NHG_INVALID_MATCH_MODE": {
+        "desc": "Fine-grained ECMP Dynamic next-hop group configuration with invalid nexthop-based match_mode in FG_NHG_LIST table.",
+        "eStrKey": "When"
     }
-}
+}