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diff --git a/grpc/src/core/ext/xds/xds_routing.h b/grpc/src/core/ext/xds/xds_routing.h
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+++ b/grpc/src/core/ext/xds/xds_routing.h
@@ -0,0 +1,101 @@
+//
+//
+// Copyright 2021 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+//
+
+#ifndef GRPC_CORE_EXT_XDS_XDS_ROUTING_H
+#define GRPC_CORE_EXT_XDS_XDS_ROUTING_H
+
+#include <grpc/support/port_platform.h>
+
+#include <vector>
+
+#include "absl/strings/string_view.h"
+
+#include <grpc/support/log.h>
+
+#include "src/core/ext/xds/xds_listener.h"
+#include "src/core/ext/xds/xds_route_config.h"
+#include "src/core/lib/matchers/matchers.h"
+#include "src/core/lib/transport/metadata_batch.h"
+
+namespace grpc_core {
+
+class XdsRouting {
+ public:
+  class VirtualHostListIterator {
+   public:
+    virtual ~VirtualHostListIterator() = default;
+    // Returns the number of virtual hosts in the list.
+    virtual size_t Size() const = 0;
+    // Returns the domain list for the virtual host at the specified index.
+    virtual const std::vector<std::string>& GetDomainsForVirtualHost(
+        size_t index) const = 0;
+  };
+
+  class RouteListIterator {
+   public:
+    virtual ~RouteListIterator() = default;
+    // Number of routes.
+    virtual size_t Size() const = 0;
+    // Returns the matchers for the route at the specified index.
+    virtual const XdsRouteConfigResource::Route::Matchers& GetMatchersForRoute(
+        size_t index) const = 0;
+  };
+
+  // Returns the index of the selected virtual host in the list.
+  static absl::optional<size_t> FindVirtualHostForDomain(
+      const VirtualHostListIterator& vhost_iterator, absl::string_view domain);
+
+  // Returns the index in route_list_iterator to use for a request with
+  // the specified path and metadata, or nullopt if no route matches.
+  static absl::optional<size_t> GetRouteForRequest(
+      const RouteListIterator& route_list_iterator, absl::string_view path,
+      grpc_metadata_batch* initial_metadata);
+
+  // Returns true if \a domain_pattern is a valid domain pattern, false
+  // otherwise.
+  static bool IsValidDomainPattern(absl::string_view domain_pattern);
+
+  // Returns the metadata value(s) for the specified key.
+  // As special cases, binary headers return a value of absl::nullopt, and
+  // "content-type" header returns "application/grpc".
+  static absl::optional<absl::string_view> GetHeaderValue(
+      grpc_metadata_batch* initial_metadata, absl::string_view header_name,
+      std::string* concatenated_value);
+
+  struct GeneratePerHttpFilterConfigsResult {
+    // Map of field name to list of elements for that field
+    std::map<std::string, std::vector<std::string>> per_filter_configs;
+    grpc_error_handle error = GRPC_ERROR_NONE;
+    // Guaranteed to be nullptr if error is GRPC_ERROR_NONE
+    grpc_channel_args* args = nullptr;
+  };
+
+  // Generates a map of per_filter_configs. \a args is consumed.
+  static GeneratePerHttpFilterConfigsResult GeneratePerHTTPFilterConfigs(
+      const std::vector<XdsListenerResource::HttpConnectionManager::HttpFilter>&
+          http_filters,
+      const XdsRouteConfigResource::VirtualHost& vhost,
+      const XdsRouteConfigResource::Route& route,
+      const XdsRouteConfigResource::Route::RouteAction::ClusterWeight*
+          cluster_weight,
+      grpc_channel_args* args);
+};
+
+}  // namespace grpc_core
+
+#endif  // GRPC_CORE_EXT_XDS_XDS_ROUTING_H