forked from flannel-io/flannel
/
vxlan_network.go
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/
vxlan_network.go
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// Copyright 2015 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.
// +build !windows
package vxlan
import (
"encoding/json"
"net"
"sync"
log "github.com/golang/glog"
"github.com/vishvananda/netlink"
"golang.org/x/net/context"
"syscall"
"github.com/coreos/flannel/backend"
"github.com/coreos/flannel/pkg/ip"
"github.com/coreos/flannel/subnet"
)
type network struct {
backend.SimpleNetwork
dev *vxlanDevice
subnetMgr subnet.Manager
}
const (
encapOverhead = 50
)
func newNetwork(subnetMgr subnet.Manager, extIface *backend.ExternalInterface, dev *vxlanDevice, _ ip.IP4Net, lease *subnet.Lease) (*network, error) {
nw := &network{
SimpleNetwork: backend.SimpleNetwork{
SubnetLease: lease,
ExtIface: extIface,
},
subnetMgr: subnetMgr,
dev: dev,
}
return nw, nil
}
func (nw *network) Run(ctx context.Context) {
wg := sync.WaitGroup{}
log.V(0).Info("watching for new subnet leases")
events := make(chan []subnet.Event)
wg.Add(1)
go func() {
subnet.WatchLeases(ctx, nw.subnetMgr, nw.SubnetLease, events)
log.V(1).Info("WatchLeases exited")
wg.Done()
}()
defer wg.Wait()
for {
select {
case evtBatch := <-events:
nw.handleSubnetEvents(evtBatch)
case <-ctx.Done():
return
}
}
}
func (nw *network) MTU() int {
return nw.ExtIface.Iface.MTU - encapOverhead
}
type vxlanLeaseAttrs struct {
VtepMAC hardwareAddr
}
func (nw *network) handleSubnetEvents(batch []subnet.Event) {
for _, event := range batch {
sn := event.Lease.Subnet
attrs := event.Lease.Attrs
if attrs.BackendType != "vxlan" {
log.Warningf("ignoring non-vxlan subnet(%s): type=%v", sn, attrs.BackendType)
continue
}
var vxlanAttrs vxlanLeaseAttrs
if err := json.Unmarshal(attrs.BackendData, &vxlanAttrs); err != nil {
log.Error("error decoding subnet lease JSON: ", err)
continue
}
// This route is used when traffic should be vxlan encapsulated
vxlanRoute := netlink.Route{
LinkIndex: nw.dev.link.Attrs().Index,
Scope: netlink.SCOPE_UNIVERSE,
Dst: sn.ToIPNet(),
Gw: sn.IP.ToIP(),
}
vxlanRoute.SetFlag(syscall.RTNH_F_ONLINK)
// directRouting is where the remote host is on the same subnet so vxlan isn't required.
directRoute := netlink.Route{
Dst: sn.ToIPNet(),
Gw: attrs.PublicIP.ToIP(),
}
var directRoutingOK = false
if nw.dev.directRouting {
if dr, err := ip.DirectRouting(attrs.PublicIP.ToIP()); err != nil {
log.Error(err)
} else {
directRoutingOK = dr
}
}
switch event.Type {
case subnet.EventAdded:
if directRoutingOK {
log.V(2).Infof("Adding direct route to subnet: %s PublicIP: %s", sn, attrs.PublicIP)
if err := netlink.RouteReplace(&directRoute); err != nil {
log.Errorf("Error adding route to %v via %v: %v", sn, attrs.PublicIP, err)
continue
}
} else {
log.V(2).Infof("adding subnet: %s PublicIP: %s VtepMAC: %s", sn, attrs.PublicIP, net.HardwareAddr(vxlanAttrs.VtepMAC))
if err := nw.dev.AddARP(neighbor{IP: sn.IP, MAC: net.HardwareAddr(vxlanAttrs.VtepMAC)}); err != nil {
log.Error("AddARP failed: ", err)
continue
}
if err := nw.dev.AddFDB(neighbor{IP: attrs.PublicIP, MAC: net.HardwareAddr(vxlanAttrs.VtepMAC)}); err != nil {
log.Error("AddFDB failed: ", err)
// Try to clean up the ARP entry then continue
if err := nw.dev.DelARP(neighbor{IP: event.Lease.Subnet.IP, MAC: net.HardwareAddr(vxlanAttrs.VtepMAC)}); err != nil {
log.Error("DelARP failed: ", err)
}
continue
}
// Set the route - the kernel would ARP for the Gw IP address if it hadn't already been set above so make sure
// this is done last.
if err := netlink.RouteReplace(&vxlanRoute); err != nil {
log.Errorf("failed to add vxlanRoute (%s -> %s): %v", vxlanRoute.Dst, vxlanRoute.Gw, err)
// Try to clean up both the ARP and FDB entries then continue
if err := nw.dev.DelARP(neighbor{IP: event.Lease.Subnet.IP, MAC: net.HardwareAddr(vxlanAttrs.VtepMAC)}); err != nil {
log.Error("DelARP failed: ", err)
}
if err := nw.dev.DelFDB(neighbor{IP: event.Lease.Attrs.PublicIP, MAC: net.HardwareAddr(vxlanAttrs.VtepMAC)}); err != nil {
log.Error("DelFDB failed: ", err)
}
continue
}
}
case subnet.EventRemoved:
if directRoutingOK {
log.V(2).Infof("Removing direct route to subnet: %s PublicIP: %s", sn, attrs.PublicIP)
if err := netlink.RouteDel(&directRoute); err != nil {
log.Errorf("Error deleting route to %v via %v: %v", sn, attrs.PublicIP, err)
}
} else {
log.V(2).Infof("removing subnet: %s PublicIP: %s VtepMAC: %s", sn, attrs.PublicIP, net.HardwareAddr(vxlanAttrs.VtepMAC))
// Try to remove all entries - don't bail out if one of them fails.
if err := nw.dev.DelARP(neighbor{IP: sn.IP, MAC: net.HardwareAddr(vxlanAttrs.VtepMAC)}); err != nil {
log.Error("DelARP failed: ", err)
}
if err := nw.dev.DelFDB(neighbor{IP: attrs.PublicIP, MAC: net.HardwareAddr(vxlanAttrs.VtepMAC)}); err != nil {
log.Error("DelFDB failed: ", err)
}
if err := netlink.RouteDel(&vxlanRoute); err != nil {
log.Errorf("failed to delete vxlanRoute (%s -> %s): %v", vxlanRoute.Dst, vxlanRoute.Gw, err)
}
}
default:
log.Error("internal error: unknown event type: ", int(event.Type))
}
}
}