| /* |
| * |
| * 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" |
| ) |
| |
| 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, _ := internal.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) |
| } |