[dash-p4] Add support to generate flow resimulation APIs (#553)

This change updates the P4 pipeline to generate the flow resimulation APIs.

The change is following the DASH flow resimulation HLD defined in the PR here: #543.

The flow resimulation could not be directly implemented using plain p4 api call. The actual pipeline implementation will be postponed until data plane app is ready.

For the generated SAI API, the routing actions type will be generated as flag defined as below:

![image](https://github.com/sonic-net/DASH/assets/1533278/6c28c649-8b74-42f2-b32b-0990abe8d645)

Author: r12f

dash-pipeline/SAI/sai_api_gen.py

@@ -8,6 +8,7 @@
     import re
     import jinja2
     import typing
+    import base64
     import jsonpath_ng.ext as jsonpath_ext
     import jsonpath_ng as jsonpath
     from utils.dash_p4 import DashP4SAIExtensions

dash-pipeline/SAI/templates/saienums.j2

@@ -1,8 +1,19 @@
 {% for enum in sai_enums %}
+/**
+ * @brief Defines a list of enums for {{ enum.name }}
+{% if enum.explicit_value %}
+ * 
+ * @flags strict
+{% endif %}
+ */
 typedef enum _sai_{{ enum.name }}_t
 {
 {% for member in enum.members %}
+{% if enum.explicit_value %}
+    SAI_{{ enum.name | upper }}_{{ member.name | upper }} = {{ member.enum_value }},
+{% else %}
     SAI_{{ enum.name | upper }}_{{ member.name | upper }},
+{% endif %}
 
 {% endfor %}
 } sai_{{ enum.name }}_t;

dash-pipeline/SAI/utils/dash_p4/dash_p4_enum.py

@@ -14,6 +14,7 @@ def __init__(self):
         super().__init__()
         self.bitwidth: int = 0
         self.members: List[DashP4EnumMember] = []
+        self.explicit_value: bool = False
 
     def parse_p4rt(self, p4rt_enum: Dict[str, Any]) -> None:
         """
@@ -39,6 +40,18 @@ def parse_p4rt(self, p4rt_enum: Dict[str, Any]) -> None:
             for enum_member in p4rt_enum[MEMBERS_TAG]
         ]
 
+        # Check if all enum values are starting from 0 and contiguous.
+        expected_value = 0
+        for member in self.members:
+            if member.enum_value != expected_value:
+                self.explicit_value = True
+                break
+            expected_value += 1
+
+        print(
+            f"Enum parsed: {self.name}, Bitwidth = {self.bitwidth}, MemberCount = {len(self.members)}, ExplicitValue = {self.explicit_value}"
+        )
+
         # Register enum type info.
         SAITypeSolver.register_sai_type(
             "sai_" + self.name + "_t",

dash-pipeline/SAI/utils/dash_p4/dash_p4_enum_member.py

@@ -1,3 +1,4 @@
+import base64
 from .common import *
 
 
@@ -9,7 +10,7 @@ class DashP4EnumMember(DashP4Object):
 
     def __init__(self):
         super().__init__()
-        self.p4rt_value: str = ""
+        self.enum_value: int = ""
 
     def parse_p4rt(self, p4rt_member: Dict[str, Any]) -> None:
         """
@@ -19,4 +20,5 @@ def parse_p4rt(self, p4rt_member: Dict[str, Any]) -> None:
 
             { "name": "INVALID", "value": "AAA=" }
         """
-        self.p4rt_value = str(p4rt_member["value"])
+        decoded_bytes = base64.b64decode(str(p4rt_member["value"]))
+        self.enum_value = int.from_bytes(decoded_bytes, byteorder="big")

dash-pipeline/bmv2/dash_counters.p4

@@ -51,6 +51,8 @@ DEFINE_ENI_HIT_COUNTER(flow_created, order=1)
 DEFINE_ENI_HIT_COUNTER(flow_create_failed, order=1)
 DEFINE_ENI_HIT_COUNTER(flow_updated, order=1)
 DEFINE_ENI_HIT_COUNTER(flow_update_failed, order=1)
+DEFINE_ENI_HIT_COUNTER(flow_updated_by_resimulation, order=1)
+DEFINE_ENI_HIT_COUNTER(flow_update_by_resimulation_failed, order=1)
 DEFINE_ENI_HIT_COUNTER(flow_deleted, order=1)
 DEFINE_ENI_HIT_COUNTER(flow_delete_failed, order=1)
 DEFINE_ENI_HIT_COUNTER(flow_aged, order=1)

dash-pipeline/bmv2/dash_metadata.p4

@@ -7,7 +7,6 @@
 #define MAX_HA_SET 1
 
 enum bit<32> dash_routing_actions_t {
-    NONE = 0,
     STATIC_ENCAP = (1 << 0),
     NAT = (1 << 1),
     NAT46 = (1 << 2),

dash-pipeline/bmv2/dash_pipeline.p4

@@ -109,7 +109,10 @@ control dash_ingress(
                          ACL_GROUPS_PARAM(inbound_v6),
                          ACL_GROUPS_PARAM(outbound_v4),
                          ACL_GROUPS_PARAM(outbound_v6),
-                         bit<1> disable_fast_path_icmp_flow_redirection) {
+                         bit<1> disable_fast_path_icmp_flow_redirection,
+                         bit<1> full_flow_resimulation_requested,
+                         bit<64> max_resimulated_flow_per_second)
+    {
         meta.eni_data.cps             = cps;
         meta.eni_data.pps             = pps;
         meta.eni_data.flows           = flows;

dash-pipeline/bmv2/dash_routing_types.p4

@@ -27,7 +27,8 @@ action route_vnet(
     inout metadata_t meta,
     @SaiVal[type="sai_object_id_t"] bit<16> dst_vnet_id,
     bit<32> meter_class_or,
-    @SaiVal[default_value="4294967295"] bit<32> meter_class_and)
+    @SaiVal[default_value="4294967295"] bit<32> meter_class_and,
+    dash_routing_actions_t routing_actions_disabled_in_flow_resimulation)
 {
     meta.target_stage = dash_pipeline_stage_t.OUTBOUND_MAPPING;
     meta.dst_vnet_id = dst_vnet_id;
@@ -45,7 +46,8 @@ action route_vnet_direct(
     @SaiVal[type="sai_ip_address_t"]
     IPv4ORv6Address overlay_ip,
     bit<32> meter_class_or,
-    @SaiVal[default_value="4294967295"] bit<32> meter_class_and)
+    @SaiVal[default_value="4294967295"] bit<32> meter_class_and,
+    dash_routing_actions_t routing_actions_disabled_in_flow_resimulation)
 {
     meta.target_stage = dash_pipeline_stage_t.OUTBOUND_MAPPING;
     meta.dst_vnet_id = dst_vnet_id;
@@ -61,7 +63,8 @@ action route_direct(
     inout headers_t hdr,
     inout metadata_t meta,
     bit<32> meter_class_or,
-    @SaiVal[default_value="4294967295"] bit<32> meter_class_and)
+    @SaiVal[default_value="4294967295"] bit<32> meter_class_and,
+    dash_routing_actions_t routing_actions_disabled_in_flow_resimulation)
 {
     meta.target_stage = dash_pipeline_stage_t.OUTBOUND_PRE_ROUTING_ACTION_APPLY;
     set_meter_attrs(meta, meter_class_or, meter_class_and);
@@ -89,7 +92,8 @@ action route_service_tunnel(
     dash_encapsulation_t dash_encapsulation,
     bit<24> tunnel_key,
     bit<32> meter_class_or,
-    @SaiVal[default_value="4294967295"] bit<32> meter_class_and)
+    @SaiVal[default_value="4294967295"] bit<32> meter_class_and,
+    dash_routing_actions_t routing_actions_disabled_in_flow_resimulation)
 {
     /* Assume the overlay addresses provided are always IPv6 and the original are IPv4 */
     /* assert(overlay_dip_is_v6 == 1 && overlay_sip_is_v6 == 1);
@@ -128,7 +132,9 @@ action set_tunnel_mapping(
     @SaiVal[type="sai_ip_address_t"] IPv4Address underlay_dip,
     EthernetAddress overlay_dmac,
     bit<1> use_dst_vnet_vni,
-    bit<32> meter_class_or)
+    bit<32> meter_class_or,
+    bit<1> flow_resimulation_requested,
+    dash_routing_actions_t routing_actions_disabled_in_flow_resimulation)
 {
     meta.target_stage = dash_pipeline_stage_t.OUTBOUND_PRE_ROUTING_ACTION_APPLY;
 
@@ -152,7 +158,9 @@ action set_private_link_mapping(
     IPv6Address overlay_dip,
     @SaiVal[type="sai_dash_encapsulation_t"] dash_encapsulation_t dash_encapsulation,
     bit<24> tunnel_key,
-    bit<32> meter_class_or)
+    bit<32> meter_class_or,
+    bit<1> flow_resimulation_requested,
+    dash_routing_actions_t routing_actions_disabled_in_flow_resimulation)
 {
     meta.target_stage = dash_pipeline_stage_t.OUTBOUND_PRE_ROUTING_ACTION_APPLY;
 

dash-pipeline/tests/libsai/vnet_out/vnet_out.cpp

@@ -211,6 +211,14 @@ int main(int argc, char **argv)
     attr.value.booldata = false;
     attrs.push_back(attr);
 
+    attr.id = SAI_ENI_ATTR_FULL_FLOW_RESIMULATION_REQUESTED;
+    attr.value.booldata = false;
+    attrs.push_back(attr);
+
+    attr.id = SAI_ENI_ATTR_MAX_RESIMULATED_FLOW_PER_SECOND;
+    attr.value.u64 = 0;
+    attrs.push_back(attr);
+
     status = dash_eni_api->create_eni(&eni_id, switch_id, attrs.size(), attrs.data());
 
     if (status != SAI_STATUS_SUCCESS)

dash-pipeline/tests/saithrift/pytest/vnet/test_saithrift_vnet.py

@@ -75,7 +75,9 @@ def test_sai_thrift_create_eni(saithrift_client):
                                     outbound_v6_stage3_dash_acl_group_id = 0,
                                     outbound_v6_stage4_dash_acl_group_id = 0,
                                     outbound_v6_stage5_dash_acl_group_id = 0,
-                                    disable_fast_path_icmp_flow_redirection = 0)
+                                    disable_fast_path_icmp_flow_redirection = 0,
+                                    full_flow_resimulation_requested = False,
+                                    max_resimulated_flow_per_second = 0)
         assert (eni != SAI_NULL_OBJECT_ID);
 
         eam = sai_thrift_eni_ether_address_map_entry_t(switch_id=switch_id, address = eth_addr)