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diff --git a/src/mongo/db/s/sharding_write_router.cpp b/src/mongo/db/s/sharding_write_router.cpp
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+++ b/src/mongo/db/s/sharding_write_router.cpp
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+/**
+ *    Copyright (C) 2021-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the Server Side Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#include "mongo/db/s/sharding_write_router.h"
+
+#include "mongo/db/catalog/collection_catalog.h"
+#include "mongo/db/s/sharding_state.h"
+#include "mongo/s/catalog_cache.h"
+#include "mongo/s/grid.h"
+
+namespace mongo {
+
+ShardingWriteRouter::ShardingWriteRouter(OperationContext* opCtx,
+                                         const NamespaceString& nss,
+                                         CatalogCache* catalogCache) {
+    if (serverGlobalParams.clusterRole == ClusterRole::ShardServer) {
+        _css = CollectionShardingState::get(opCtx, nss);
+        auto collDesc = _css->getCollectionDescription(opCtx);
+
+        _reshardKeyPattern = collDesc.getReshardingKeyIfShouldForwardOps();
+        if (_reshardKeyPattern) {
+            _ownershipFilter = _css->getOwnershipFilter(
+                opCtx, CollectionShardingState::OrphanCleanupPolicy::kAllowOrphanCleanup);
+            _shardKeyPattern = ShardKeyPattern(collDesc.getKeyPattern());
+
+            const auto& reshardingFields = collDesc.getReshardingFields();
+            invariant(reshardingFields);
+            const auto& donorFields = reshardingFields->getDonorFields();
+            invariant(donorFields);
+
+            _reshardingChunkMgr = uassertStatusOK(catalogCache->getCollectionRoutingInfo(
+                opCtx, donorFields->getTempReshardingNss(), true /* allowLocks */));
+        }
+    }
+}
+
+CollectionShardingState* ShardingWriteRouter::getCollectionShardingState() const {
+    return _css;
+}
+
+boost::optional<ShardId> ShardingWriteRouter::getReshardingDestinedRecipient(
+    const BSONObj& fullDocument) const {
+    if (!_reshardKeyPattern) {
+        return boost::none;
+    }
+
+    invariant(_ownershipFilter);
+    invariant(_shardKeyPattern);
+    invariant(_reshardingChunkMgr);
+
+    if (!_ownershipFilter->keyBelongsToMe(_shardKeyPattern->extractShardKeyFromDoc(fullDocument))) {
+        return boost::none;
+    }
+
+    auto shardKey = _reshardKeyPattern->extractShardKeyFromDocThrows(fullDocument);
+    return _reshardingChunkMgr->findIntersectingChunkWithSimpleCollation(shardKey).getShardId();
+}
+
+}  // namespace mongo