[http] API changes to split path header normalization and forwarding

api/envoy/extensions/filters/network/http_connection_manager/v3/http_connection_manager.proto

@@ -12,6 +12,7 @@ import "envoy/config/route/v3/route.proto";
 import "envoy/config/route/v3/scoped_route.proto";
 import "envoy/config/trace/v3/http_tracer.proto";
 import "envoy/type/tracing/v3/custom_tag.proto";
+import "envoy/type/v3/path_transformations.proto";
 import "envoy/type/v3/percent.proto";
 
 import "google/protobuf/any.proto";
@@ -33,7 +34,7 @@ option (udpa.annotations.file_status).package_version_status = ACTIVE;
 // HTTP connection manager :ref:`configuration overview <config_http_conn_man>`.
 // [#extension: envoy.filters.network.http_connection_manager]
 
-// [#next-free-field: 43]
+// [#next-free-field: 44]
 message HttpConnectionManager {
   option (udpa.annotations.versioning).previous_message_type =
       "envoy.config.filter.network.http_connection_manager.v2.HttpConnectionManager";
@@ -238,6 +239,38 @@ message HttpConnectionManager {
     google.protobuf.BoolValue enabled = 3;
   }
 
+  // [#not-implemented-hide] Transformations that apply to path headers. Transformations are applied
+  // before any processing of requests by HTTP filters, routing, and matching. Only the normalized
+  // path will be visible internally if a transformation is enabled. Any path rewrites that the
+  // router performs (e.g. :ref:`regex_rewrite
+  // <envoy_api_field_config.route.v3.RouteAction.regex_rewrite>` or :ref:`prefix_rewrite
+  // <envoy_api_field_config.route.v3.RouteAction.prefix_rewrite>`) will apply to the *:path* header
+  // destined for the upstream.
+  //
+  // Note: access logging and tracing will show the original *:path* header.
+  message PathNormalizationOptions {
+    // [#not-implemented-hide] Normalization applies internally before any processing of requests by
+    // HTTP filters, routing, and matching *and* will affect the forwarded *:path* header. Defaults
+    // to :ref:`NormalizePathRFC3986
+    // <envoy_api_msg_type.v3.PathTransformation.Operation.NormalizePathRFC3986>`. When not
+    // specified, this value may be overridden by the runtime variable
+    // :ref:`http_connection_manager.normalize_path<config_http_conn_man_runtime_normalize_path>`.
+    // Envoy will respond with 400 to paths that are malformed (e.g. for paths that fail RFC 3986
+    // normalization due to disallowed characters.)
+    type.v3.PathTransformation forwarding_transformation = 1;
+
+    // [#not-implemented-hide] Normalization only applies internally before any processing of
+    // requests by HTTP filters, routing, and matching. These will be applied after full
+    // transformation is applied. The *:path* header before this transformation will be restored in
+    // the router filter and sent upstream unless it was mutated by a filter. Defaults to no
+    // transformations.
+    // Multiple actions can be applied in the same Transformation, forming a sequential
+    // pipeline. The transformations will be performed in the order that they appear. Envoy will
+    // respond with 400 to paths that are malformed (e.g. for paths that fail RFC 3986
+    // normalization due to disallowed characters.)
+    type.v3.PathTransformation http_filter_transformation = 2;
+  }
+
   reserved 27, 11;
 
   reserved "idle_timeout";
@@ -582,6 +615,16 @@ message HttpConnectionManager {
   // *not* the deprecated but similarly named :ref:`stream_error_on_invalid_http_messaging
   // <envoy_v3_api_field_config.core.v3.Http2ProtocolOptions.stream_error_on_invalid_http_messaging>`
   google.protobuf.BoolValue stream_error_on_invalid_http_message = 40;
+
+  // [#not-implemented-hide:] Path normalization configuration. This includes
+  // configurations for transformations (e.g. RFC 3986 normalization or merge
+  // adjacent slashes) and the policy to apply them. The policy determines
+  // whether transformations affect the forwarded *:path* header. RFC 3986 path
+  // normalization is enabled by default and the default policy is that the
+  // normalized header will be forwarded. See :ref:`PathNormalizationOptions
+  // <envoy_api_msg_extensions.filters.network.http_connection_manager.v3.PathNormalizationOptions>`
+  // for details.
+  PathNormalizationOptions path_normalization_options = 43;
 }
 
 // The configuration to customize local reply returned by Envoy.

api/envoy/type/v3/path_transformations.proto

@@ -0,0 +1,57 @@
+syntax = "proto3";
+
+package envoy.type.v3;
+
+import "udpa/annotations/status.proto";
+import "validate/validate.proto";
+
+option java_package = "io.envoyproxy.envoy.type.v3";
+option java_outer_classname = "PathTransformationsProto";
+option java_multiple_files = true;
+option (udpa.annotations.file_status).package_version_status = ACTIVE;
+
+// [#protodoc-title: Path Transformations API]
+
+// PathTransformation defines an API to apply a sequence of operations that can be used to alter
+// text before it is used for matching or routing. Multiple actions can be applied in the same
+// Transformation, forming a sequential pipeline. The transformations will be performed in the order
+// that they appear.
+//
+// This API is a work in progress.
+
+message PathTransformation {
+  // A type of operation to alter text.
+  message Operation {
+    // Should text be normalized according to RFC 3986? This typically is used for path headers
+    // before any processing of requests by HTTP filters or routing. This applies percent-encoded
+    // normalization and path segment normalization. Fails on characters disallowed in URLs
+    // (e.g. NULLs). See `Normalization and Comparison
+    // <https://tools.ietf.org/html/rfc3986#section-6>`_ for details of normalization. Note that
+    // this options does not perform `case normalization
+    // <https://tools.ietf.org/html/rfc3986#section-6.2.2.1>`_
+    message NormalizePathRFC3986 {
+    }
+
+    // Determines if adjacent slashes are merged into one. A common use case is for a request path
+    // header. Using this option in `:ref: PathNormalizationOptions
+    // <envoy_api_msg_extensions.filters.network.http_connection_manager.v3.HttpConnectionManager.PathNormalizationOptions>`
+    // will allow incoming requests with path `//dir///file` to match against route with `prefix`
+    // match set to `/dir`. When using for header transformations, note that slash merging is not
+    // part of `HTTP spec <https://tools.ietf.org/html/rfc3986>`_ and is provided for convenience.
+    message MergeSlashes {
+    }
+
+    oneof operation_specifier {
+      option (validate.required) = true;
+
+      // Enable path normalization per RFC 3986.
+      NormalizePathRFC3986 normalize_path_rfc_3986 = 2;
+
+      // Enable merging adjacent slashes.
+      MergeSlashes merge_slashes = 3;
+    }
+  }
+
+  // A list of operations to apply. Transformations will be performed in the order that they appear.
+  repeated Operation operations = 1;
+}

docs/root/api-v3/types/types.rst

@@ -13,6 +13,7 @@ Types
   ../type/v3/ratelimit_unit.proto
   ../type/v3/semantic_version.proto
   ../type/v3/token_bucket.proto
+  ../type/v3/transformations.proto
   ../type/matcher/v3/metadata.proto
   ../type/matcher/v3/node.proto
   ../type/matcher/v3/number.proto