WIP: config: Add FilterChain Discovery Service.

api/envoy/api/v2/BUILD

@@ -97,6 +97,24 @@ api_go_grpc_library(
     ],
 )
 
+api_proto_library_internal(
+    name = "fcds",
+    srcs = ["fcds.proto"],
+    has_services = 1,
+    visibility = [":friends"],
+    deps = [
+        ":discovery",
+    ],
+)
+
+api_go_grpc_library(
+    name = "fcds",
+    proto = ":fcds",
+    deps = [
+        ":discovery_go_proto",
+    ],
+)
+
 api_proto_library_internal(
     name = "lds",
     srcs = ["lds.proto"],
@@ -106,6 +124,7 @@ api_proto_library_internal(
         ":discovery",
         "//envoy/api/v2/core:address",
         "//envoy/api/v2/core:base",
+        "//envoy/api/v2/core:config_source",
         "//envoy/api/v2/listener",
     ],
 )
@@ -117,6 +136,7 @@ api_go_grpc_library(
         ":discovery_go_proto",
         "//envoy/api/v2/core:address_go_proto",
         "//envoy/api/v2/core:base_go_proto",
+        "//envoy/api/v2/core:config_source_go_proto",
         "//envoy/api/v2/listener:listener_go_proto",
     ],
 )

api/envoy/api/v2/fcds.proto

@@ -0,0 +1,36 @@
+syntax = "proto3";
+
+package envoy.api.v2;
+
+option java_generic_services = true;
+
+import "envoy/api/v2/discovery.proto";
+
+import "google/api/annotations.proto";
+import "google/protobuf/wrappers.proto";
+
+import "validate/validate.proto";
+import "gogoproto/gogo.proto";
+
+option (gogoproto.equal_all) = true;
+
+// [#protodoc-title: Filter Chain Discovery Service]
+
+// The resource_names field in DiscoveryRequest specifies a listener.
+// The resources field in DiscoveryResponse is values of type listener.FilterChain.
+service FilterChainDiscoveryService {
+  rpc StreamRoutes(stream DiscoveryRequest) returns (stream DiscoveryResponse) {
+  }
+
+  rpc IncrementalFilterChains(stream IncrementalDiscoveryRequest)
+      returns (stream IncrementalDiscoveryResponse) {
+  }
+
+  rpc FetchFilterChains(DiscoveryRequest) returns (DiscoveryResponse) {
+    option (google.api.http) = {
+      post: "/v2/discovery:filterchains"
+      body: "*"
+    };
+  }
+}
+

api/envoy/api/v2/lds.proto

@@ -6,6 +6,7 @@ option java_generic_services = true;
 
 import "envoy/api/v2/core/address.proto";
 import "envoy/api/v2/core/base.proto";
+import "envoy/api/v2/core/config_source.proto";
 import "envoy/api/v2/discovery.proto";
 import "envoy/api/v2/listener/listener.proto";
 
@@ -37,7 +38,7 @@ service ListenerDiscoveryService {
   }
 }
 
-// [#comment:next free field: 16]
+// [#comment:next free field: 17]
 message Listener {
   // The unique name by which this listener is known. If no name is provided,
   // Envoy will allocate an internal UUID for the listener. If the listener is to be dynamically
@@ -57,10 +58,21 @@ message Listener {
   // :ref:`FilterChainMatch <envoy_api_msg_listener.FilterChainMatch>` criteria is used on a
   // connection.
   //
+  // Precisely one of filter_chains and fdcs_config must be set.
+  //
   // Example using SNI for filter chain selection can be found in the
   // :ref:`FAQ entry <faq_how_to_setup_sni>`.
-  repeated listener.FilterChain filter_chains = 3
-      [(validate.rules).repeated .min_items = 1, (gogoproto.nullable) = false];
+  repeated listener.FilterChain filter_chains = 3 [(gogoproto.nullable) = false];
+
+  message FcdsConfig {
+    core.ConfigSource fds_config = 1;
+
+    // Optional alternative to the listener name to present to FCDS.
+    string filter_chain_name = 2;
+  }
+
+  // Precisely one of filter_chains and fdcs_config must be set.
+  FcdsConfig fcds_config = 17;
 
   // If a connection is redirected using *iptables*, the port on which the proxy
   // receives it might be different from the original destination address. When this flag is set to