k3s/vendor/github.com/flannel-io/flannel/backend/route_network.go

271 lines
7.3 KiB
Go

// +build !windows
// 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.
package backend
import (
"bytes"
"net"
"sync"
"time"
"github.com/flannel-io/flannel/subnet"
"github.com/vishvananda/netlink"
"golang.org/x/net/context"
log "k8s.io/klog"
)
const (
routeCheckRetries = 10
)
type RouteNetwork struct {
SimpleNetwork
BackendType string
routes []netlink.Route
v6Routes []netlink.Route
SM subnet.Manager
GetRoute func(lease *subnet.Lease) *netlink.Route
GetV6Route func(lease *subnet.Lease) *netlink.Route
Mtu int
LinkIndex int
}
func (n *RouteNetwork) MTU() int {
return n.Mtu
}
func (n *RouteNetwork) Run(ctx context.Context) {
wg := sync.WaitGroup{}
log.Info("Watching for new subnet leases")
evts := make(chan []subnet.Event)
wg.Add(1)
go func() {
subnet.WatchLeases(ctx, n.SM, n.SubnetLease, evts)
wg.Done()
}()
n.routes = make([]netlink.Route, 0, 10)
wg.Add(1)
go func() {
n.routeCheck(ctx)
wg.Done()
}()
defer wg.Wait()
for {
select {
case evtBatch, ok := <-evts:
if !ok {
log.Infof("evts chan closed")
return
}
n.handleSubnetEvents(evtBatch)
}
}
}
func (n *RouteNetwork) handleSubnetEvents(batch []subnet.Event) {
for _, evt := range batch {
switch evt.Type {
case subnet.EventAdded:
if evt.Lease.Attrs.BackendType != n.BackendType {
log.Warningf("Ignoring non-%v subnet: type=%v", n.BackendType, evt.Lease.Attrs.BackendType)
continue
}
if evt.Lease.EnableIPv4 {
log.Infof("Subnet added: %v via %v", evt.Lease.Subnet, evt.Lease.Attrs.PublicIP)
route := n.GetRoute(&evt.Lease)
routeAdd(route, netlink.FAMILY_V4, n.addToRouteList, n.removeFromV4RouteList)
}
if evt.Lease.EnableIPv6 {
log.Infof("Subnet added: %v via %v", evt.Lease.IPv6Subnet, evt.Lease.Attrs.PublicIPv6)
route := n.GetV6Route(&evt.Lease)
routeAdd(route, netlink.FAMILY_V6, n.addToV6RouteList, n.removeFromV6RouteList)
}
case subnet.EventRemoved:
if evt.Lease.Attrs.BackendType != n.BackendType {
log.Warningf("Ignoring non-%v subnet: type=%v", n.BackendType, evt.Lease.Attrs.BackendType)
continue
}
if evt.Lease.EnableIPv4 {
log.Info("Subnet removed: ", evt.Lease.Subnet)
route := n.GetRoute(&evt.Lease)
// Always remove the route from the route list.
n.removeFromV4RouteList(*route)
if err := netlink.RouteDel(route); err != nil {
log.Errorf("Error deleting route to %v: %v", evt.Lease.Subnet, err)
}
}
if evt.Lease.EnableIPv6 {
log.Info("Subnet removed: ", evt.Lease.IPv6Subnet)
route := n.GetV6Route(&evt.Lease)
// Always remove the route from the route list.
n.removeFromV6RouteList(*route)
if err := netlink.RouteDel(route); err != nil {
log.Errorf("Error deleting route to %v: %v", evt.Lease.IPv6Subnet, err)
}
}
default:
log.Error("Internal error: unknown event type: ", int(evt.Type))
}
}
}
func routeAdd(route *netlink.Route, ipFamily int, addToRouteList, removeFromRouteList func(netlink.Route)) {
addToRouteList(*route)
// Check if route exists before attempting to add it
routeList, err := netlink.RouteListFiltered(ipFamily, &netlink.Route{Dst: route.Dst}, netlink.RT_FILTER_DST)
if err != nil {
log.Warningf("Unable to list routes: %v", err)
}
if len(routeList) > 0 && !routeEqual(routeList[0], *route) {
// Same Dst different Gw or different link index. Remove it, correct route will be added below.
log.Warningf("Replacing existing route to %v with %v", routeList[0], route)
if err := netlink.RouteDel(&routeList[0]); err != nil {
log.Errorf("Effor deleteing route to %v: %v", routeList[0].Dst, err)
return
}
removeFromRouteList(routeList[0])
}
routeList, err = netlink.RouteListFiltered(ipFamily, &netlink.Route{Dst: route.Dst}, netlink.RT_FILTER_DST)
if err != nil {
log.Warningf("Unable to list routes: %v", err)
}
if len(routeList) > 0 && routeEqual(routeList[0], *route) {
// Same Dst and same Gw, keep it and do not attempt to add it.
log.Infof("Route to %v already exists, skipping.", route)
} else if err := netlink.RouteAdd(route); err != nil {
log.Errorf("Error adding route to %v", route)
return
}
routeList, err = netlink.RouteListFiltered(ipFamily, &netlink.Route{Dst: route.Dst}, netlink.RT_FILTER_DST)
if err != nil {
log.Warningf("Unable to list routes: %v", err)
}
}
func (n *RouteNetwork) addToRouteList(route netlink.Route) {
n.routes = addToRouteList(&route, n.routes)
}
func (n *RouteNetwork) addToV6RouteList(route netlink.Route) {
n.v6Routes = addToRouteList(&route, n.v6Routes)
}
func addToRouteList(route *netlink.Route, routes []netlink.Route) []netlink.Route {
for _, r := range routes {
if routeEqual(r, *route) {
return routes
}
}
return append(routes, *route)
}
func (n *RouteNetwork) removeFromV4RouteList(route netlink.Route) {
n.routes = n.removeFromRouteList(&route, n.routes)
}
func (n *RouteNetwork) removeFromV6RouteList(route netlink.Route) {
n.v6Routes = n.removeFromRouteList(&route, n.v6Routes)
}
func (n *RouteNetwork) removeFromRouteList(route *netlink.Route, routes []netlink.Route) []netlink.Route {
for index, r := range routes {
if routeEqual(r, *route) {
routes = append(routes[:index], routes[index+1:]...)
return routes
}
}
return routes
}
func (n *RouteNetwork) routeCheck(ctx context.Context) {
for {
select {
case <-ctx.Done():
return
case <-time.After(routeCheckRetries * time.Second):
n.checkSubnetExistInV4Routes()
n.checkSubnetExistInV6Routes()
}
}
}
func (n *RouteNetwork) checkSubnetExistInV4Routes() {
n.checkSubnetExistInRoutes(n.routes, netlink.FAMILY_V4)
}
func (n *RouteNetwork) checkSubnetExistInV6Routes() {
n.checkSubnetExistInRoutes(n.v6Routes, netlink.FAMILY_V6)
}
func (n *RouteNetwork) checkSubnetExistInRoutes(routes []netlink.Route, ipFamily int) {
routeList, err := netlink.RouteList(nil, ipFamily)
if err == nil {
for _, route := range routes {
exist := false
for _, r := range routeList {
if r.Dst == nil {
continue
}
if routeEqual(r, route) {
exist = true
break
}
}
if !exist {
if err := netlink.RouteAdd(&route); err != nil {
if nerr, ok := err.(net.Error); !ok {
log.Errorf("Error recovering route to %v: %v, %v", route.Dst, route.Gw, nerr)
}
continue
} else {
log.Infof("Route recovered %v : %v", route.Dst, route.Gw)
}
}
}
} else {
log.Errorf("Error fetching route list. Will automatically retry: %v", err)
}
}
func routeEqual(x, y netlink.Route) bool {
// For ipip backend, when enabling directrouting, link index of some routes may change
// For both ipip and host-gw backend, link index may also change if updating ExtIface
if x.Dst.IP.Equal(y.Dst.IP) && x.Gw.Equal(y.Gw) && bytes.Equal(x.Dst.Mask, y.Dst.Mask) && x.LinkIndex == y.LinkIndex {
return true
}
return false
}