diff --git a/vendor/google.golang.org/grpc/internal/envconfig/xds.go b/vendor/google.golang.org/grpc/internal/envconfig/xds.go
new file mode 100644
index 0000000..9bad03c
--- /dev/null
+++ b/vendor/google.golang.org/grpc/internal/envconfig/xds.go
@@ -0,0 +1,97 @@
+/*
+ *
+ * Copyright 2020 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.
+ *
+ */
+
+package envconfig
+
+import (
+	"os"
+	"strings"
+)
+
+const (
+	// XDSBootstrapFileNameEnv is the env variable to set bootstrap file name.
+	// Do not use this and read from env directly. Its value is read and kept in
+	// variable BootstrapFileName.
+	//
+	// When both bootstrap FileName and FileContent are set, FileName is used.
+	XDSBootstrapFileNameEnv = "GRPC_XDS_BOOTSTRAP"
+	// XDSBootstrapFileContentEnv is the env variable to set bootstrapp file
+	// content. Do not use this and read from env directly. Its value is read
+	// and kept in variable BootstrapFileName.
+	//
+	// When both bootstrap FileName and FileContent are set, FileName is used.
+	XDSBootstrapFileContentEnv = "GRPC_XDS_BOOTSTRAP_CONFIG"
+
+	ringHashSupportEnv           = "GRPC_XDS_EXPERIMENTAL_ENABLE_RING_HASH"
+	clientSideSecuritySupportEnv = "GRPC_XDS_EXPERIMENTAL_SECURITY_SUPPORT"
+	aggregateAndDNSSupportEnv    = "GRPC_XDS_EXPERIMENTAL_ENABLE_AGGREGATE_AND_LOGICAL_DNS_CLUSTER"
+	rbacSupportEnv               = "GRPC_XDS_EXPERIMENTAL_RBAC"
+	federationEnv                = "GRPC_EXPERIMENTAL_XDS_FEDERATION"
+	rlsInXDSEnv                  = "GRPC_EXPERIMENTAL_XDS_RLS_LB"
+
+	c2pResolverTestOnlyTrafficDirectorURIEnv = "GRPC_TEST_ONLY_GOOGLE_C2P_RESOLVER_TRAFFIC_DIRECTOR_URI"
+)
+
+var (
+	// XDSBootstrapFileName holds the name of the file which contains xDS
+	// bootstrap configuration. Users can specify the location of the bootstrap
+	// file by setting the environment variable "GRPC_XDS_BOOTSTRAP".
+	//
+	// When both bootstrap FileName and FileContent are set, FileName is used.
+	XDSBootstrapFileName = os.Getenv(XDSBootstrapFileNameEnv)
+	// XDSBootstrapFileContent holds the content of the xDS bootstrap
+	// configuration. Users can specify the bootstrap config by setting the
+	// environment variable "GRPC_XDS_BOOTSTRAP_CONFIG".
+	//
+	// When both bootstrap FileName and FileContent are set, FileName is used.
+	XDSBootstrapFileContent = os.Getenv(XDSBootstrapFileContentEnv)
+	// XDSRingHash indicates whether ring hash support is enabled, which can be
+	// disabled by setting the environment variable
+	// "GRPC_XDS_EXPERIMENTAL_ENABLE_RING_HASH" to "false".
+	XDSRingHash = !strings.EqualFold(os.Getenv(ringHashSupportEnv), "false")
+	// XDSClientSideSecurity is used to control processing of security
+	// configuration on the client-side.
+	//
+	// Note that there is no env var protection for the server-side because we
+	// have a brand new API on the server-side and users explicitly need to use
+	// the new API to get security integration on the server.
+	XDSClientSideSecurity = !strings.EqualFold(os.Getenv(clientSideSecuritySupportEnv), "false")
+	// XDSAggregateAndDNS indicates whether processing of aggregated cluster
+	// and DNS cluster is enabled, which can be enabled by setting the
+	// environment variable
+	// "GRPC_XDS_EXPERIMENTAL_ENABLE_AGGREGATE_AND_LOGICAL_DNS_CLUSTER" to
+	// "true".
+	XDSAggregateAndDNS = strings.EqualFold(os.Getenv(aggregateAndDNSSupportEnv), "true")
+
+	// XDSRBAC indicates whether xDS configured RBAC HTTP Filter is enabled,
+	// which can be disabled by setting the environment variable
+	// "GRPC_XDS_EXPERIMENTAL_RBAC" to "false".
+	XDSRBAC = !strings.EqualFold(os.Getenv(rbacSupportEnv), "false")
+
+	// XDSFederation indicates whether federation support is enabled.
+	XDSFederation = strings.EqualFold(os.Getenv(federationEnv), "true")
+
+	// XDSRLS indicates whether processing of Cluster Specifier plugins and
+	// support for the RLS CLuster Specifier is enabled, which can be enabled by
+	// setting the environment variable "GRPC_EXPERIMENTAL_XDS_RLS_LB" to
+	// "true".
+	XDSRLS = strings.EqualFold(os.Getenv(rlsInXDSEnv), "true")
+
+	// C2PResolverTestOnlyTrafficDirectorURI is the TD URI for testing.
+	C2PResolverTestOnlyTrafficDirectorURI = os.Getenv(c2pResolverTestOnlyTrafficDirectorURIEnv)
+)