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ipsec_network.go
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/
ipsec_network.go
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// Copyright 2017 flannel 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.
//go:build !windows
// +build !windows
package ipsec
import (
"fmt"
"net"
"strconv"
"sync"
"github.com/flannel-io/flannel/pkg/backend"
"github.com/flannel-io/flannel/pkg/lease"
"github.com/flannel-io/flannel/pkg/subnet"
"github.com/vishvananda/netlink"
"golang.org/x/net/context"
log "k8s.io/klog/v2"
)
const (
/*
New IP header (Tunnel Mode) : 20
SPI (ESP Header) : 4
Sequence (ESP Header) : 4
ESP-AES IV : 16
ESP-AES Pad : 0-15
Pad length (ESP Trailer) : 1
Next Header (ESP Trailer) : 1
ESP-SHA-256 ICV : 16
*/
ipsecOverhead = 77
udpEncapOverhead = 8
defaultReqID = 11
)
type network struct {
backend.SimpleNetwork
password string
UDPEncap bool
sm subnet.Manager
iked *CharonIKEDaemon
}
func newNetwork(sm subnet.Manager, extIface *backend.ExternalInterface,
UDPEncap bool, password string, ikeDaemon *CharonIKEDaemon,
l *lease.Lease) (*network, error) {
n := &network{
SimpleNetwork: backend.SimpleNetwork{
SubnetLease: l,
ExtIface: extIface,
},
sm: sm,
iked: ikeDaemon,
password: password,
UDPEncap: UDPEncap,
}
return n, nil
}
func (n *network) Run(ctx context.Context) {
err := n.iked.LoadSharedKey(n.SimpleNetwork.SubnetLease.Attrs.PublicIP.ToIP().String(), n.password)
if err != nil {
log.Errorf("Failed to load PSK: %v", err)
return
}
wg := sync.WaitGroup{}
defer wg.Wait()
log.Info("Watching for new subnet leases")
evts := make(chan []lease.Event)
wg.Add(1)
go func() {
subnet.WatchLeases(ctx, n.sm, n.SubnetLease, evts)
log.Info("WatchLeases exited")
wg.Done()
}()
for {
evtsBatch, ok := <-evts
if !ok {
log.Infof("evts chan closed")
return
}
log.Info("Handling event")
n.handleSubnetEvents(evtsBatch)
}
}
func (n *network) handleSubnetEvents(batch []lease.Event) {
for _, evt := range batch {
switch evt.Type {
case lease.EventAdded:
log.Info("Subnet added: ", evt.Lease.Subnet)
if evt.Lease.Attrs.BackendType != "ipsec" {
log.Warningf("Ignoring non-ipsec event: type: %v", evt.Lease.Attrs.BackendType)
continue
}
if evt.Lease.Subnet.Equal(n.SubnetLease.Subnet) {
log.Warningf("Ignoring own lease add event: %+v", evt.Lease)
continue
}
if err := n.AddIPSECPolicies(&evt.Lease, defaultReqID); err != nil {
log.Errorf("error adding ipsec policy: %v", err)
}
if err := n.iked.LoadSharedKey(evt.Lease.Attrs.PublicIP.String(), n.password); err != nil {
log.Errorf("error loading shared key into IKE daemon: %v", err)
}
if err := n.iked.LoadConnection(n.SubnetLease, &evt.Lease, strconv.Itoa(defaultReqID),
strconv.FormatBool(n.UDPEncap)); err != nil {
log.Errorf("error loading connection into IKE daemon: %v", err)
}
case lease.EventRemoved:
log.Info("Subnet removed: ", evt.Lease.Subnet)
if evt.Lease.Attrs.BackendType != "ipsec" {
log.Warningf("Ignoring non-ipsec event: type: %v", evt.Lease.Attrs.BackendType)
continue
}
if evt.Lease.Subnet.Equal(n.SubnetLease.Subnet) {
log.Warningf("Ignoring own lease remove event: %+v", evt.Lease)
continue
}
if err := n.iked.UnloadCharonConnection(n.SubnetLease, &evt.Lease); err != nil {
log.Errorf("error unloading charon connections: %v", err)
}
if err := n.DeleteIPSECPolicies(n.SubnetLease.Subnet.ToIPNet(), evt.Lease.Subnet.ToIPNet(),
n.SubnetLease.Attrs.PublicIP.ToIP(), evt.Lease.Attrs.PublicIP.ToIP(), defaultReqID); err != nil {
log.Errorf("error deleting ipsec policies: %v", err)
}
}
}
}
func (n *network) MTU() int {
mtu := n.ExtIface.Iface.MTU - ipsecOverhead
if n.UDPEncap {
mtu -= udpEncapOverhead
}
return mtu
}
func (n *network) AddIPSECPolicies(remoteLease *lease.Lease, reqID int) error {
err := AddXFRMPolicy(n.SubnetLease, remoteLease, netlink.XFRM_DIR_OUT, reqID)
if err != nil {
return fmt.Errorf("error adding ipsec out policy: %v", err)
}
err = AddXFRMPolicy(remoteLease, n.SubnetLease, netlink.XFRM_DIR_IN, reqID)
if err != nil {
return fmt.Errorf("error adding ipsec in policy: %v", err)
}
err = AddXFRMPolicy(remoteLease, n.SubnetLease, netlink.XFRM_DIR_FWD, reqID)
if err != nil {
return fmt.Errorf("error adding ipsec fwd policy: %v", err)
}
return nil
}
func (n *network) DeleteIPSECPolicies(localSubnet, remoteSubnet *net.IPNet, localPublicIP, remotePublicIP net.IP, reqID int) error {
err := DeleteXFRMPolicy(localSubnet, remoteSubnet, localPublicIP, remotePublicIP, netlink.XFRM_DIR_OUT, reqID)
if err != nil {
return fmt.Errorf("error deleting ipsec out policy: %v", err)
}
err = DeleteXFRMPolicy(remoteSubnet, localSubnet, remotePublicIP, localPublicIP, netlink.XFRM_DIR_IN, reqID)
if err != nil {
return fmt.Errorf("error deleting ipsec in policy: %v", err)
}
err = DeleteXFRMPolicy(remoteSubnet, localSubnet, remotePublicIP, localPublicIP, netlink.XFRM_DIR_FWD, reqID)
if err != nil {
return fmt.Errorf("error deleting ipsec fwd policy: %v", err)
}
return nil
}