snapshot of https://github.com/grpc/grpc-go.git (master, 2026-09-15; blobs > 131072B omitted)

credentials/alts/internal/handshaker/service/service.go

@@ -0,0 +1,91 @@
+/*
+ *
+ * Copyright 2018 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 service manages connections between the VM application and the ALTS
+// handshaker service.
+package service
+
+import (
+	"sync"
+	"time"
+
+	grpc "google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+	"google.golang.org/grpc/internal/envconfig"
+	"google.golang.org/grpc/keepalive"
+)
+
+var (
+	// mu guards hsConnMap and hsDialer.
+	mu sync.Mutex
+	// hsConn represents a mapping from a hypervisor handshaker service address
+	// to a corresponding connection to a hypervisor handshaker service
+	// instance.
+	hsConnMap = make(map[string]*grpc.ClientConn)
+)
+
+// Dial dials the handshake service in the hypervisor. If a connection has
+// already been established, this function returns it. Otherwise, a new
+// connection is created.
+func Dial(hsAddress string) (*grpc.ClientConn, error) {
+	mu.Lock()
+	defer mu.Unlock()
+
+	hsConn, ok := hsConnMap[hsAddress]
+	if !ok {
+		// Create a new connection to the handshaker service. Note that
+		// this connection stays open until the application is closed.
+		// Disable the service config to avoid unnecessary TXT record lookups that
+		// cause timeouts with some versions of systemd-resolved.
+		var err error
+		opts := []grpc.DialOption{
+			grpc.WithTransportCredentials(insecure.NewCredentials()),
+			grpc.WithDisableServiceConfig(),
+		}
+		if envconfig.ALTSHandshakerKeepaliveParams {
+			opts = append(opts, grpc.WithKeepaliveParams(keepalive.ClientParameters{
+				Timeout: 10 * time.Second,
+				Time:    10 * time.Minute,
+			}))
+		}
+		hsConn, err = grpc.NewClient(hsAddress, opts...)
+		if err != nil {
+			return nil, err
+		}
+		hsConnMap[hsAddress] = hsConn
+	}
+	return hsConn, nil
+}
+
+// CloseForTesting closes all open connections to the handshaker service.
+//
+// For testing purposes only.
+func CloseForTesting() error {
+	for _, hsConn := range hsConnMap {
+		if hsConn == nil {
+			continue
+		}
+		if err := hsConn.Close(); err != nil {
+			return err
+		}
+	}
+
+	// Reset the connection map.
+	hsConnMap = make(map[string]*grpc.ClientConn)
+	return nil
+}