[202506] [yang] VNET_ROUTE_TUNNEL yang model support for consistent hashing (#24684) (#1900)

Master PR: sonic-net/sonic-buildimage#24684

Why I did it
To support consistent ECMP for vxlan tunnels, according to
specifications in sonic-net/SONiC#2099

Work item tracking
Microsoft ADO (number only):
How I did it
Added multi-value support for endpoint, mac and vni. Added
consistent_hashing_buckets.

How to verify it
Run the tests added in this PR or build image with these changes and set
the new attributes.

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#### Why I did it

##### Work item tracking
- Microsoft ADO **(number only)**:

#### How I did it

#### How to verify it

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Author: zjswhhh

src/sonic-yang-mgmt/sonic_yang_ext.py

@@ -35,6 +35,9 @@
     ('BUFFER_PORT_INGRESS_PROFILE_LIST', 'profile_list'): ',',
     ('PORT', 'adv_speeds'): ',',
     ('PORT', 'adv_interface_types'): ',',
+    ('VNET_ROUTE_TUNNEL', 'endpoint'): ',',
+    ('VNET_ROUTE_TUNNEL', 'mac_address'): ',',
+    ('VNET_ROUTE_TUNNEL', 'vni'): ',',
 }
 
 """

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

@@ -2740,13 +2740,20 @@ monitoring sessions for the vnet routes and is optional.
 ### VNET_ROUTE_TUNNEL
 
 VNET_ROUTE_TUNNEL table has vnet_name|prefix as the object key, where vnet_name is the name of the VNet and prefix is the ip4 prefix associated with the route tunnel. The table includes the following attributes:
-- ENDPOINT: The endpoint/nexthop tunnel IP (mandatory). It is used to identify the endpoint of the tunnel.
-- MAC_ADDRESS: The inner destination MAC address in the encapsulated packet (optional).  It should be a 12-hexadeimal digit value.
-- VNI: The VNI value in the encapsulated packet (optional). It should be a numeric value.
+- ENDPOINT: Comma-separated endpoint/nexthop tunnel IPs (mandatory). They are used to identify the endpoints of the tunnel.
+- MAC_ADDRESS: Comma-separated inner destination MAC addresses in the encapsulated packet (optional).  They should be 12-hexadecimal digit values.
+- VNI: Comma-separated VNI values in the encapsulated packet (optional). They should be numeric values.
+- CONSISTENT_HASHING_BUCKETS: Number of consistent hashing buckets to use, if consistent hashing is desired (optional). It should be a numeric value.
 
 ```
 {
   "VNET_ROUTE_TUNNEL": {
+        "Vnet_1000|100.200.1.1/32": {
+        "endpoint": "192.174.1.1,192.174.1.2",
+        "mac_address": "f8:25:84:98:22:a1,f8:25:84:98:22:a2",
+        "vni": "10010,10011",
+        "consistent_hashing_buckets": "10"
+    },
     "Vnet_2000|100.100.1.1/32": {
         "endpoint": "192.168.1.1",
         "mac_address": "f9:22:83:99:22:a2"

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

@@ -2406,9 +2406,10 @@
         },
         "VNET_ROUTE_TUNNEL" : {
             "vnet1|10.0.0.0/24" : {
-                "endpoint": "192.168.1.2",
-                "mac_address": "f9:22:83:99:22:a2",
-                "vni": "10011"
+                "endpoint": "192.168.1.1,192.168.1.2",
+                "mac_address": "f9:22:83:99:22:a1,f9:22:83:99:22:a2",
+                "vni": "10011,10012",
+                "consistent_hashing_buckets": "10"
             }
         },
         "PORT_QOS_MAP": {

src/sonic-yang-models/tests/yang_model_tests/tests/vnet.json

@@ -69,11 +69,59 @@
 
     "VNET_ROUTE_TUNNEL_TEST_MISSING_ENDPOINT": {
         "desc": "VNET route tunnel configuration with missing mandatory attribute (endpoint) in VNET_ROUTE_TUNNEL_LIST table.",
-        "eStr": "Missing required element \"endpoint\" in \"VNET_ROUTE_TUNNEL_LIST\"."
+        "eStrKey": "MinElements"
     },
 
     "VNET_ROUTE_TUNNEL_TEST_NONEXISTENT_VNET": {
         "desc": "VNET route tunnel configuration referencing a non-existent VNET name, violating the must condition.",
-        "eStr": "Leafref \"/sonic-vnet:sonic-vnet/sonic-vnet:VNET/sonic-vnet:VNET_LIST/sonic-vnet:name\" of value \"NonexistentVnet\" points to a non-existing leaf"
+        "eStrKey" : "LeafRef"
+    },
+
+    "VNET_ROUTE_TUNNEL_TEST_MULTI_ENDPOINT": {
+        "desc": "VNET route tunnel configuration with multiple comma-separated endpoint IPs in VNET_ROUTE_TUNNEL_LIST table."
+    },
+
+    "VNET_ROUTE_TUNNEL_TEST_MULTI_MAC": {
+        "desc": "VNET route tunnel configuration with multiple comma-separated MAC addresses in VNET_ROUTE_TUNNEL_LIST table."
+    },
+
+    "VNET_ROUTE_TUNNEL_TEST_MULTI_VNI": {
+        "desc": "VNET route tunnel configuration with multiple comma-separated VNI values in VNET_ROUTE_TUNNEL_LIST table."
+    },
+
+    "VNET_ROUTE_TUNNEL_TEST_MULTI_ALL": {
+        "desc": "VNET route tunnel configuration with multiple comma-separated values for all fields (endpoint, mac_address, vni) in VNET_ROUTE_TUNNEL_LIST table."
+    },
+
+    "VNET_ROUTE_TUNNEL_TEST_INVALID_MULTI_ENDPOINT": {
+        "desc": "VNET route tunnel configuration with invalid IP in comma-separated endpoint list.",
+        "eStrKey": "Pattern"
+    },
+
+    "VNET_ROUTE_TUNNEL_TEST_INVALID_MULTI_MAC": {
+        "desc": "VNET route tunnel configuration with invalid MAC in comma-separated mac_address list.",
+        "eStrKey": "Pattern"
+    },
+
+    "VNET_ROUTE_TUNNEL_TEST_INVALID_MULTI_VNI": {
+        "desc": "VNET route tunnel configuration with invalid VNI in comma-separated vni list.",
+        "eStrKey": "Range"
+    },
+
+    "VNET_ROUTE_TUNNEL_TEST_CONSISTENT_HASHING": {
+        "desc": "VNET route tunnel configuration with consistent_hashing_buckets field."
+    },
+
+    "VNET_ROUTE_TUNNEL_TEST_CONSISTENT_HASHING_MAX": {
+        "desc": "VNET route tunnel configuration with consistent_hashing_buckets maximum value (65535)."
+    },
+
+    "VNET_ROUTE_TUNNEL_TEST_CONSISTENT_HASHING_WITH_MULTI": {
+        "desc": "VNET route tunnel configuration with consistent_hashing_buckets and multiple endpoints."
+    },
+
+    "VNET_ROUTE_TUNNEL_TEST_INVALID_CONSISTENT_HASHING": {
+        "desc": "VNET route tunnel configuration with invalid consistent_hashing_buckets value (exceeds uint16 max).",
+        "eStrKey": "InvalidValue"
     }
 }