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listener.go
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listener.go
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// Copyright (c) The ClusterLink 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 server
import (
"context"
"fmt"
"net"
"strconv"
"strings"
corev3 "github.com/envoyproxy/go-control-plane/envoy/config/core/v3"
authv3 "github.com/envoyproxy/go-control-plane/envoy/service/auth/v3"
"github.com/clusterlink-net/clusterlink/pkg/controlplane/api"
)
// CreateListener starts a listener to an imported service.
func (d *Dataplane) CreateListener(name, ip string, port uint32) {
listenTarget := ip + ":" + strconv.Itoa(int(port))
d.listenerEnd[name] = make(chan bool)
d.logger.Infof("Starting a listener for imported service %s at %s.", name, listenTarget)
acceptor, err := net.Listen("tcp", listenTarget)
if err != nil {
d.logger.Infof("Error listening to por: %v.", err)
return
}
go func() {
if err = d.serveEgressConnections(name, acceptor); err != nil {
d.logger.Errorf("Failed to serve egress connection on %s: %+v.", listenTarget, err)
}
}()
<-d.listenerEnd[name]
d.logger.Infof("Ending the listener for imported service %s at %s.", name, listenTarget)
acceptor.Close()
}
func (d *Dataplane) serveEgressConnections(name string, listener net.Listener) error {
for {
d.logger.Infof("Serving for imported service %s at %s.", name, listener.Addr())
conn, err := listener.Accept()
if err != nil {
d.logger.Error("Failed to accept egress connection", err)
return err
}
d.logger.Debugf(
"Received an egress connection at listener for imported service %s from %s.", name, conn.RemoteAddr().String())
d.logger.Debugf("Connection: %+v.", conn)
targetPeer, accessToken, err := d.getEgressAuth(name, strings.Split(conn.RemoteAddr().String(), ":")[0])
if err != nil {
d.logger.Infof("Failed egress authorization: %v.", err)
conn.Close()
continue
}
d.logger.Infof("Received auth from controlplane: target peer: %s with %s", targetPeer, accessToken)
targetHost, err := d.GetClusterHost(targetPeer)
if err != nil {
d.logger.Errorf("Unable to get cluster host :%v.", err)
conn.Close()
continue
}
d.tlsConfigLock.RLock()
tlsConfig := d.tlsConfig.Clone()
d.tlsConfigLock.RUnlock()
tlsConfig.ServerName = targetHost
go func() {
err := d.initiateEgressConnection(targetPeer, accessToken, conn, tlsConfig)
if err != nil {
d.logger.Errorf("Failed to initiate egress connection: %v.", err)
conn.Close()
}
}()
}
}
// getEgressAuth returns the target cluster and authorization token for the outgoing connection.
func (d *Dataplane) getEgressAuth(name, sourceIP string) (string, string, error) { //nolint:gocritic // unnamedResult
components := strings.SplitN(name, "/", 2)
authzReq := &authv3.CheckRequest{
Attributes: &authv3.AttributeContext{
Source: &authv3.AttributeContext_Peer{
Address: &corev3.Address{
Address: &corev3.Address_EnvoyInternalAddress{
EnvoyInternalAddress: &corev3.EnvoyInternalAddress{},
},
},
},
Request: &authv3.AttributeContext_Request{
Http: &authv3.AttributeContext_HttpRequest{
Headers: map[string]string{
api.ImportNamespaceHeader: components[0],
api.ImportNameHeader: components[1],
api.ClientIPHeader: sourceIP,
},
},
},
},
}
resp, err := d.authzClient.Check(context.Background(), authzReq)
if err != nil {
d.logger.Errorf("Error authorizing egress request: %v.", err)
return "", "", err
}
okResp, ok := resp.HttpResponse.(*authv3.CheckResponse_OkResponse)
if !ok {
if deniedResp, denied := resp.HttpResponse.(*authv3.CheckResponse_DeniedResponse); denied {
return "", "", fmt.Errorf("egress connection denied: %s", deniedResp.DeniedResponse.Body)
}
return "", "", fmt.Errorf("unknown authorization response: %+v", resp)
}
// get target and access token from response headers
var accessToken, targetCluster string
for _, header := range okResp.OkResponse.Headers {
if header.Header.Key == api.TargetClusterHeader {
targetCluster = header.Header.Value
} else if header.Header.Key == api.AuthorizationHeader {
accessToken = header.Header.Value
}
}
if targetCluster == "" {
return "", "", fmt.Errorf("missing target cluster")
}
if accessToken == "" {
return "", "", fmt.Errorf("missing access token")
}
return targetCluster, accessToken, nil
}