forked from TrueCloudLab/distribution
128 lines
3.9 KiB
Go
128 lines
3.9 KiB
Go
/*
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*
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* Copyright 2021 gRPC authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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package google
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import (
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"context"
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"net"
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"net/url"
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"strings"
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"google.golang.org/grpc/credentials"
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"google.golang.org/grpc/internal"
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)
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const cfeClusterNamePrefix = "google_cfe_"
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const cfeClusterResourceNamePrefix = "/envoy.config.cluster.v3.Cluster/google_cfe_"
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const cfeClusterAuthorityName = "traffic-director-c2p.xds.googleapis.com"
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// clusterTransportCreds is a combo of TLS + ALTS.
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//
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// On the client, ClientHandshake picks TLS or ALTS based on address attributes.
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// - if attributes has cluster name
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// - if cluster name has prefix "google_cfe_", or
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// "xdstp://traffic-director-c2p.xds.googleapis.com/envoy.config.cluster.v3.Cluster/google_cfe_",
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// use TLS
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// - otherwise, use ALTS
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//
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// - else, do TLS
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//
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// On the server, ServerHandshake always does TLS.
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type clusterTransportCreds struct {
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tls credentials.TransportCredentials
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alts credentials.TransportCredentials
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}
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func newClusterTransportCreds(tls, alts credentials.TransportCredentials) *clusterTransportCreds {
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return &clusterTransportCreds{
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tls: tls,
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alts: alts,
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}
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}
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// clusterName returns the xDS cluster name stored in the attributes in the
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// context.
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func clusterName(ctx context.Context) string {
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chi := credentials.ClientHandshakeInfoFromContext(ctx)
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if chi.Attributes == nil {
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return ""
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}
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cluster, _ := internal.GetXDSHandshakeClusterName(chi.Attributes)
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return cluster
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}
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// isDirectPathCluster returns true if the cluster in the context is a
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// directpath cluster, meaning ALTS should be used.
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func isDirectPathCluster(ctx context.Context) bool {
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cluster := clusterName(ctx)
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if cluster == "" {
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// No cluster; not xDS; use TLS.
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return false
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}
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if strings.HasPrefix(cluster, cfeClusterNamePrefix) {
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// xDS cluster prefixed by "google_cfe_"; use TLS.
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return false
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}
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if !strings.HasPrefix(cluster, "xdstp:") {
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// Other xDS cluster name; use ALTS.
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return true
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}
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u, err := url.Parse(cluster)
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if err != nil {
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// Shouldn't happen, but assume ALTS.
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return true
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}
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// If authority AND path match our CFE checks, use TLS; otherwise use ALTS.
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return u.Host != cfeClusterAuthorityName || !strings.HasPrefix(u.Path, cfeClusterResourceNamePrefix)
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}
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func (c *clusterTransportCreds) ClientHandshake(ctx context.Context, authority string, rawConn net.Conn) (net.Conn, credentials.AuthInfo, error) {
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if isDirectPathCluster(ctx) {
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// If attributes have cluster name, and cluster name is not cfe, it's a
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// backend address, use ALTS.
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return c.alts.ClientHandshake(ctx, authority, rawConn)
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}
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return c.tls.ClientHandshake(ctx, authority, rawConn)
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}
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func (c *clusterTransportCreds) ServerHandshake(conn net.Conn) (net.Conn, credentials.AuthInfo, error) {
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return c.tls.ServerHandshake(conn)
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}
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func (c *clusterTransportCreds) Info() credentials.ProtocolInfo {
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// TODO: this always returns tls.Info now, because we don't have a cluster
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// name to check when this method is called. This method doesn't affect
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// anything important now. We may want to revisit this if it becomes more
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// important later.
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return c.tls.Info()
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}
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func (c *clusterTransportCreds) Clone() credentials.TransportCredentials {
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return &clusterTransportCreds{
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tls: c.tls.Clone(),
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alts: c.alts.Clone(),
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}
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}
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func (c *clusterTransportCreds) OverrideServerName(s string) error {
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if err := c.tls.OverrideServerName(s); err != nil {
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return err
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}
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return c.alts.OverrideServerName(s)
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}
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