feat: gitea client

vendor/google.golang.org/grpc/credentials/google/xds.go

@@ -0,0 +1,128 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+package google
+
+import (
+	"context"
+	"net"
+	"net/url"
+	"strings"
+
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/internal/xds"
+)
+
+const cfeClusterNamePrefix = "google_cfe_"
+const cfeClusterResourceNamePrefix = "/envoy.config.cluster.v3.Cluster/google_cfe_"
+const cfeClusterAuthorityName = "traffic-director-c2p.xds.googleapis.com"
+
+// clusterTransportCreds is a combo of TLS + ALTS.
+//
+// On the client, ClientHandshake picks TLS or ALTS based on address attributes.
+// - if attributes has cluster name
+//   - if cluster name has prefix "google_cfe_", or
+//     "xdstp://traffic-director-c2p.xds.googleapis.com/envoy.config.cluster.v3.Cluster/google_cfe_",
+//     use TLS
+//   - otherwise, use ALTS
+//
+// - else, do TLS
+//
+// On the server, ServerHandshake always does TLS.
+type clusterTransportCreds struct {
+	tls  credentials.TransportCredentials
+	alts credentials.TransportCredentials
+}
+
+func newClusterTransportCreds(tls, alts credentials.TransportCredentials) *clusterTransportCreds {
+	return &clusterTransportCreds{
+		tls:  tls,
+		alts: alts,
+	}
+}
+
+// clusterName returns the xDS cluster name stored in the attributes in the
+// context.
+func clusterName(ctx context.Context) string {
+	chi := credentials.ClientHandshakeInfoFromContext(ctx)
+	if chi.Attributes == nil {
+		return ""
+	}
+	cluster, _ := xds.GetXDSHandshakeClusterName(chi.Attributes)
+	return cluster
+}
+
+// isDirectPathCluster returns true if the cluster in the context is a
+// directpath cluster, meaning ALTS should be used.
+func isDirectPathCluster(ctx context.Context) bool {
+	cluster := clusterName(ctx)
+	if cluster == "" {
+		// No cluster; not xDS; use TLS.
+		return false
+	}
+	if strings.HasPrefix(cluster, cfeClusterNamePrefix) {
+		// xDS cluster prefixed by "google_cfe_"; use TLS.
+		return false
+	}
+	if !strings.HasPrefix(cluster, "xdstp:") {
+		// Other xDS cluster name; use ALTS.
+		return true
+	}
+	u, err := url.Parse(cluster)
+	if err != nil {
+		// Shouldn't happen, but assume ALTS.
+		return true
+	}
+	// If authority AND path match our CFE checks, use TLS; otherwise use ALTS.
+	return u.Host != cfeClusterAuthorityName || !strings.HasPrefix(u.Path, cfeClusterResourceNamePrefix)
+}
+
+func (c *clusterTransportCreds) ClientHandshake(ctx context.Context, authority string, rawConn net.Conn) (net.Conn, credentials.AuthInfo, error) {
+	if isDirectPathCluster(ctx) {
+		// If attributes have cluster name, and cluster name is not cfe, it's a
+		// backend address, use ALTS.
+		return c.alts.ClientHandshake(ctx, authority, rawConn)
+	}
+	return c.tls.ClientHandshake(ctx, authority, rawConn)
+}
+
+func (c *clusterTransportCreds) ServerHandshake(conn net.Conn) (net.Conn, credentials.AuthInfo, error) {
+	return c.tls.ServerHandshake(conn)
+}
+
+func (c *clusterTransportCreds) Info() credentials.ProtocolInfo {
+	// TODO: this always returns tls.Info now, because we don't have a cluster
+	// name to check when this method is called. This method doesn't affect
+	// anything important now. We may want to revisit this if it becomes more
+	// important later.
+	return c.tls.Info()
+}
+
+func (c *clusterTransportCreds) Clone() credentials.TransportCredentials {
+	return &clusterTransportCreds{
+		tls:  c.tls.Clone(),
+		alts: c.alts.Clone(),
+	}
+}
+
+func (c *clusterTransportCreds) OverrideServerName(s string) error {
+	if err := c.tls.OverrideServerName(s); err != nil {
+		return err
+	}
+	return c.alts.OverrideServerName(s)
+}