Add service proxy
This adds a service proxy based on nfproxy and changes to the service IP allocation to make it work.
Also adds support for masquerading outbound traffic for outbound network connectivity.
Test Plan:
Currently manually tested by creating an alpine pod and running 'apk add curl && curl -k https://192.168.188.1:443/'.
Will be covered later by CTS.
Bug: T810
X-Origin-Diff: phab/D580
GitOrigin-RevId: cace863fd8c2f045560f8abf84c40cc77bc275d4
diff --git a/core/internal/kubernetes/nfproxy/nfproxy.go b/core/internal/kubernetes/nfproxy/nfproxy.go
new file mode 100644
index 0000000..25962bf
--- /dev/null
+++ b/core/internal/kubernetes/nfproxy/nfproxy.go
@@ -0,0 +1,104 @@
+// Copyright 2020 The Monogon Project Authors.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// 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 nfproxy is a Kubernetes Service IP proxy based exclusively on the Linux nftables interface.
+// It uses netfilter's NAT capabilities to accept traffic on service IPs and DNAT it to the respective endpoint.
+package nfproxy
+
+import (
+ "context"
+ "errors"
+ "fmt"
+ "net"
+ "os"
+ "time"
+
+ "git.monogon.dev/source/nexantic.git/core/internal/common/supervisor"
+
+ "github.com/sbezverk/nfproxy/pkg/controller"
+ "github.com/sbezverk/nfproxy/pkg/nftables"
+ "github.com/sbezverk/nfproxy/pkg/proxy"
+ v1 "k8s.io/api/core/v1"
+ metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+ "k8s.io/apimachinery/pkg/labels"
+ "k8s.io/apimachinery/pkg/selection"
+ kubeinformers "k8s.io/client-go/informers"
+ "k8s.io/client-go/kubernetes"
+ "k8s.io/client-go/kubernetes/scheme"
+ "k8s.io/client-go/tools/record"
+)
+
+type Service struct {
+ // Traffic in ClusterCIDR is assumed to be originated inside the cluster and will not be SNATed
+ ClusterCIDR net.IPNet
+ // A Kubernetes ClientSet with read access to endpoints and services
+ ClientSet kubernetes.Interface
+}
+
+func (s *Service) Run(ctx context.Context) error {
+ var ipv4ClusterCIDR string
+ var ipv6ClusterCIDR string
+ if s.ClusterCIDR.IP.To4() == nil && s.ClusterCIDR.IP.To16() != nil {
+ ipv6ClusterCIDR = s.ClusterCIDR.String()
+ } else if s.ClusterCIDR.IP.To4() != nil {
+ ipv4ClusterCIDR = s.ClusterCIDR.String()
+ } else {
+ return errors.New("invalid ClusterCIDR")
+ }
+ nfti, err := nftables.InitNFTables(ipv4ClusterCIDR, ipv6ClusterCIDR)
+ if err != nil {
+ return fmt.Errorf("failed to initialize nftables with error: %w", err)
+ }
+
+ // Create event recorder to report events into K8s
+ hostname, err := os.Hostname()
+ if err != nil {
+ return fmt.Errorf("failed to get local host name with error: %w", err)
+ }
+ eventBroadcaster := record.NewBroadcaster()
+ recorder := eventBroadcaster.NewRecorder(scheme.Scheme, v1.EventSource{Component: "nfproxy", Host: hostname})
+
+ // Create new proxy controller with endpoint slices enabled
+ // https://kubernetes.io/docs/concepts/services-networking/endpoint-slices/
+ nfproxy := proxy.NewProxy(nfti, hostname, recorder, true)
+
+ // Create special informer which doesn't track headless services
+ noHeadlessEndpoints, err := labels.NewRequirement(v1.IsHeadlessService, selection.DoesNotExist, nil)
+ if err != nil {
+ return fmt.Errorf("failed to create Requirement for noHeadlessEndpoints: %w", err)
+ }
+ labelSelector := labels.NewSelector()
+ labelSelector = labelSelector.Add(*noHeadlessEndpoints)
+
+ kubeInformerFactory := kubeinformers.NewSharedInformerFactoryWithOptions(s.ClientSet, time.Minute*5,
+ kubeinformers.WithTweakListOptions(func(options *metav1.ListOptions) {
+ options.LabelSelector = labelSelector.String()
+ }))
+
+ svcController := controller.NewServiceController(nfproxy, s.ClientSet, kubeInformerFactory.Core().V1().Services())
+ ep := controller.NewEndpointSliceController(nfproxy, s.ClientSet, kubeInformerFactory.Discovery().V1beta1().EndpointSlices())
+ kubeInformerFactory.Start(ctx.Done())
+
+ if err = svcController.Start(ctx.Done()); err != nil {
+ return fmt.Errorf("error running Service controller: %w", err)
+ }
+ if err = ep.Start(ctx.Done()); err != nil {
+ return fmt.Errorf("error running endpoint controller: %w", err)
+ }
+ supervisor.Signal(ctx, supervisor.SignalHealthy)
+ supervisor.Signal(ctx, supervisor.SignalDone)
+ return nil
+}