Add max size.

dash-pipeline/SAI/templates/saiapi.h.j2

@@ -166,6 +166,8 @@ typedef enum _sai_{{ table.name }}_attr_t
      * @type {{ sai_attr.type }}
 {% if sai_attr.isreadonly == 'true' %}
      * @flags READ_ONLY
+{% else if sai_attr.iscreateonly == 'true' %}
+     * @flags CREATE_ONLY
 {% else %}
      * @flags CREATE_AND_SET
 {% endif %}

dash-pipeline/SAI/utils/dash_p4/dash_p4_table.py

@@ -127,6 +127,9 @@ def __table_with_counters(self, program: Dict[str, Any]) -> None:
     def __parse_table_keys(self, p4rt_table: Dict[str, Any]) -> None:
         for p4rt_table_key in p4rt_table[MATCH_FIELDS_TAG]:
             table_key = DashP4TableKey.from_p4rt(p4rt_table_key)
+
+            # For table keys, we currently require the values to be explicitly set.
+            table_key.default = None
 
             if self.is_object != "false":
                 table_key.is_entry_key = False
@@ -378,7 +381,7 @@ def create_sai_attributes(self, sai_api: SaiApi) -> None:
             elif len(self.keys) > 1:
                 for key in self.keys:
                     if not key.is_object_key:
-                        sai_api.attributes.extend(key.to_sai_attribute(self.name, create_only=True))
+                        sai_api.attributes.extend(key.to_sai_attribute(self.name))
 
         # Add all the action parameters into the attributes.
         for attr in self.sai_attributes:

dash-pipeline/SAI/utils/dash_p4/dash_p4_table_attribute.py

@@ -15,6 +15,7 @@ def __init__(self):
         self.bitwidth: int = 0
         self.isresourcetype: Optional[str] = None
         self.isreadonly: Optional[str] = None
+        self.iscreateonly: Optional[str] = None
         self.object_name: Optional[str] = None
         self.skipattr: Optional[str] = None
         self.match_type: str = ""
@@ -59,6 +60,8 @@ def _parse_sai_table_attribute_annotation(
                         self.isresourcetype = str(kv["value"]["stringValue"])
                     elif kv["key"] == "isreadonly":
                         self.isreadonly = str(kv["value"]["stringValue"])
+                    elif kv["key"] == "iscreateonly":
+                        self.iscreateonly = str(kv["value"]["stringValue"])
                     elif kv["key"] == "objects":
                         self.object_name = str(kv["value"]["stringValue"])
                     elif kv["key"] == "skipattr":
@@ -125,7 +128,7 @@ def to_sai_struct_entry(self, table_name: str) -> List[SaiStructEntry]:
 
         return entries
 
-    def to_sai_attribute(self, table_name: str, create_only: bool = False, add_action_valid_only_check: bool = False) -> List[SaiAttribute]:
+    def to_sai_attribute(self, table_name: str, add_action_valid_only_check: bool = False) -> List[SaiAttribute]:
         name = self.get_sai_name(table_name)
         description = self.get_sai_description(table_name)
 
@@ -136,9 +139,13 @@ def to_sai_attribute(self, table_name: str, create_only: bool = False, add_actio
         if self.isreadonly == "true":
             sai_flags = "READ_ONLY"
             default_value = None
-        elif create_only:
-            sai_flags = "MANDATORY_ON_CREATE | CREATE_ONLY"
-            default_value = None
+        elif self.iscreateonly == "true":
+            if self.default == None:
+                sai_flags = "MANDATORY_ON_CREATE | CREATE_ONLY"
+            else:
+                sai_flags = "CREATE_ONLY"
+
+            default_value = self.default
             allow_null = False
         else:
             sai_flags = "CREATE_AND_SET"

dash-pipeline/SAI/utils/dash_p4/dash_p4_table_key.py

@@ -11,6 +11,7 @@ class DashP4TableKey(DashP4TableAttribute):
 
     def __init__(self):
         super().__init__()
+        self.iscreateonly: str = "true"
         self.ip_is_v6_field_id: int = 0
 
     def parse_p4rt(self, p4rt_table_key: Dict[str, Any]) -> None:

dash-pipeline/bmv2/README.md

@@ -30,7 +30,8 @@ Available tags are:
 - `default_value`: Override the default value for this key or action parameter.
 - `isresourcetype`: When set to "true", we generate a corresponding SAI tag in SAI APIs: `@isresourcetype true`.
 - `objects`: Space separated list of SAI object type this value accepts. When set, we force this value to be a SAI object id, and generate a corresponding SAI tag in SAI APIs: `@objects <list>`.
-- `isreadonly`: When set to "true", we generate force this value to be read-only in SAI API using: `@flags READ_ONLY`, otherwise, we generate `@flags CREATE_AND_SET`.
+- `isreadonly`: When set to "true", we generate force this value to be read-only in SAI API using: `@flags READ_ONLY`, otherwise, we generate `@flags CREATE_AND_SET`. It cannot be used with `iscreateonly`.
+- `iscreateonly`: When set to "true", we generate force this value to be create-only in SAI API using: `@flags CREATE_ONLY`, otherwise, we generate `@flags CREATE_AND_SET`. It cannot be used with `isreadonly`.
 - `skipattr`: When set to "true", we skip this attribute in SAI API generation.
 
 #### `@SaiCounter`: Counters

dash-pipeline/bmv2/dash_metadata.p4

@@ -322,6 +322,7 @@ struct metadata_t {
     encap_data_t tunnel_data;
     overlay_rewrite_data_t overlay_data;
     bit<16> dash_tunnel_id;
+    bit<32> dash_tunnel_max_member_size;
     bit<16> dash_tunnel_member_index;
     bit<16> dash_tunnel_member_id;
     bit<16> dash_tunnel_next_hop_id;

dash-pipeline/bmv2/stages/tunnel_stage.p4

@@ -11,12 +11,17 @@ control tunnel_stage(
 
         bit<24> tunnel_key,
 
+        @SaiVal[default_value="1", iscreateonly="true"]
+        bit<32> max_member_size,
+
         @SaiVal[type="sai_ip_address_t"]
         IPv4Address dip,
 
         @SaiVal[type="sai_ip_address_t"]
         IPv4Address sip)
     {
+        meta.dash_tunnel_max_member_size = max_member_size;
+
         meta.tunnel_data.dash_encapsulation = dash_encapsulation;
         meta.tunnel_data.vni = tunnel_key;
         meta.tunnel_data.underlay_sip = sip == 0 ? hdr.u0_ipv4.src_addr : sip;
@@ -100,12 +105,19 @@ control tunnel_stage(
 
         tunnel.apply();
 
-        if (meta.tunnel_data.underlay_dip == 0) {
-            // If underlay_dip is not set by the tunnel, we are using the tunnel as ECMP group.
-
-            // TODO: Calculate based on packet and tunnel member size.
-            // Currently, we will have to use 0 here, because we don't know how many tunnel members we will have.
+        // If max member size is greater than 1, the tunnel is programmed with multiple members.
+        if (meta.dash_tunnel_max_member_size > 1) {
+#if defined(TARGET_BMV2_V1MODEL)
+            // Select tunnel member based on the hash of the packet tuples.
+            hash(meta.dash_tunnel_member_index, HashAlgorithm.crc32, (bit<32>)0, {
+                meta.dst_ip_addr,
+                meta.src_ip_addr,
+                meta.src_l4_port,
+                meta.dst_l4_port
+            }, meta.dash_tunnel_max_member_size);
+#else
             meta.dash_tunnel_member_index = 0;
+#endif
             tunnel_member_select.apply();
 
             tunnel_member.apply();