forked from metallb/metallb
/
bgp_controller.go
260 lines (235 loc) · 7.18 KB
/
bgp_controller.go
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// Copyright 2017 Google Inc.
//
// 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 main
import (
"fmt"
"io"
"net"
"reflect"
"sort"
"time"
"go.universe.tf/metallb/internal/bgp"
"go.universe.tf/metallb/internal/config"
"k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/labels"
"github.com/go-kit/kit/log"
)
type peer struct {
cfg *config.Peer
bgp session
}
type bgpController struct {
logger log.Logger
myNode string
nodeLabels labels.Set
peers []*peer
svcAds map[string][]*bgp.Advertisement
}
func (c *bgpController) SetConfig(l log.Logger, cfg *config.Config) error {
newPeers := make([]*peer, 0, len(cfg.Peers))
newPeers:
for _, p := range cfg.Peers {
for i, ep := range c.peers {
if ep == nil {
continue
}
if reflect.DeepEqual(p, ep.cfg) {
newPeers = append(newPeers, ep)
c.peers[i] = nil
continue newPeers
}
}
// No existing peers match, create a new one.
newPeers = append(newPeers, &peer{
cfg: p,
})
}
oldPeers := c.peers
c.peers = newPeers
for _, p := range oldPeers {
if p == nil {
continue
}
l.Log("event", "peerRemoved", "peer", p.cfg.Addr, "reason", "removedFromConfig", "msg", "peer deconfigured, closing BGP session")
if p.bgp != nil {
if err := p.bgp.Close(); err != nil {
l.Log("op", "setConfig", "error", err, "peer", p.cfg.Addr, "msg", "failed to shut down BGP session")
}
}
}
return c.syncPeers(l)
}
// nodeHasHealthyEndpoint return true if this node has at least one healthy endpoint.
func nodeHasHealthyEndpoint(eps *v1.Endpoints, node string) bool {
ready := map[string]bool{}
for _, subset := range eps.Subsets {
for _, ep := range subset.Addresses {
if ep.NodeName == nil || *ep.NodeName != node {
continue
}
if _, ok := ready[ep.IP]; !ok {
// Only set true if nothing else has expressed an
// opinion. This means that false will take precedence
// if there's any unready ports for a given endpoint.
ready[ep.IP] = true
}
}
for _, ep := range subset.NotReadyAddresses {
ready[ep.IP] = false
}
}
for _, r := range ready {
if r {
// At least one fully healthy endpoint on this machine.
return true
}
}
return false
}
func (c *bgpController) ShouldAnnounce(l log.Logger, name string, svc *v1.Service, eps *v1.Endpoints) string {
// Should we advertise? Yes, if externalTrafficPolicy is Cluster,
// or Local && there's a ready local endpoint.
if svc.Spec.ExternalTrafficPolicy == v1.ServiceExternalTrafficPolicyTypeLocal && !nodeHasHealthyEndpoint(eps, c.myNode) {
return "noLocalEndpoints"
}
return ""
}
// Called when either the peer list or node labels have changed,
// implying that the set of running BGP sessions may need tweaking.
func (c *bgpController) syncPeers(l log.Logger) error {
var (
errs int
needUpdateAds bool
)
for _, p := range c.peers {
// First, determine if the peering should be active for this
// node.
shouldRun := false
for _, ns := range p.cfg.NodeSelectors {
if ns.Matches(c.nodeLabels) {
shouldRun = true
break
}
}
// Now, compare current state to intended state, and correct.
if p.bgp != nil && !shouldRun {
// Oops, session is running but shouldn't be. Shut it down.
l.Log("event", "peerRemoved", "peer", p.cfg.Addr, "reason", "filteredByNodeSelector", "msg", "peer deconfigured, closing BGP session")
if err := p.bgp.Close(); err != nil {
l.Log("op", "syncPeers", "error", err, "peer", p.cfg.Addr, "msg", "failed to shut down BGP session")
}
p.bgp = nil
} else if p.bgp == nil && shouldRun {
// Session doesn't exist, but should be running. Create
// it.
l.Log("event", "peerAdded", "peer", p.cfg.Addr, "msg", "peer configured, starting BGP session")
var routerID net.IP
if p.cfg.RouterID != nil {
routerID = p.cfg.RouterID
}
s, err := newBGP(c.logger, fmt.Sprintf("%s:%d", p.cfg.Addr, p.cfg.Port), p.cfg.MyASN, routerID, p.cfg.ASN, p.cfg.HoldTime, p.cfg.Password)
if err != nil {
l.Log("op", "syncPeers", "error", err, "peer", p.cfg.Addr, "msg", "failed to create BGP session")
errs++
} else {
p.bgp = s
needUpdateAds = true
}
}
}
if needUpdateAds {
// Some new sessions came up, resync advertisement state.
if err := c.updateAds(); err != nil {
l.Log("op", "updateAds", "error", err, "msg", "failed to update BGP advertisements")
return err
}
}
if errs > 0 {
return fmt.Errorf("%d BGP sessions failed to start", errs)
}
return nil
}
func (c *bgpController) SetBalancer(l log.Logger, name string, lbIP net.IP, pool *config.Pool) error {
c.svcAds[name] = nil
for _, adCfg := range pool.BGPAdvertisements {
m := net.CIDRMask(adCfg.AggregationLength, 32)
ad := &bgp.Advertisement{
Prefix: &net.IPNet{
IP: lbIP.Mask(m),
Mask: m,
},
LocalPref: adCfg.LocalPref,
}
for comm := range adCfg.Communities {
ad.Communities = append(ad.Communities, comm)
}
sort.Slice(ad.Communities, func(i, j int) bool { return ad.Communities[i] < ad.Communities[j] })
c.svcAds[name] = append(c.svcAds[name], ad)
}
if err := c.updateAds(); err != nil {
return err
}
l.Log("event", "updatedAdvertisements", "numAds", len(c.svcAds[name]), "msg", "making advertisements using BGP")
return nil
}
func (c *bgpController) updateAds() error {
var allAds []*bgp.Advertisement
for _, ads := range c.svcAds {
// This list might contain duplicates, but that's fine,
// they'll get compacted by the session code when it's
// calculating advertisements.
//
// TODO: be more intelligent about compacting advertisements
// and detecting conflicting advertisements.
allAds = append(allAds, ads...)
}
for _, peer := range c.peers {
if peer.bgp == nil {
continue
}
if err := peer.bgp.Set(allAds...); err != nil {
return err
}
}
return nil
}
func (c *bgpController) DeleteBalancer(l log.Logger, name, reason string) error {
if _, ok := c.svcAds[name]; !ok {
return nil
}
delete(c.svcAds, name)
return c.updateAds()
}
type session interface {
io.Closer
Set(advs ...*bgp.Advertisement) error
}
func (c *bgpController) SetLeader(log.Logger, bool) {}
func (c *bgpController) SetNode(l log.Logger, node *v1.Node) error {
nodeLabels := node.Labels
if nodeLabels == nil {
nodeLabels = map[string]string{}
}
ns := labels.Set(nodeLabels)
if c.nodeLabels != nil && labels.Equals(c.nodeLabels, ns) {
// Node labels unchanged, no action required.
return nil
}
c.nodeLabels = ns
l.Log("event", "nodeLabelsChanged", "msg", "Node labels changed, resyncing BGP peers")
return c.syncPeers(l)
}
var newBGP = func(logger log.Logger, addr string, myASN uint32, routerID net.IP, asn uint32, hold time.Duration, password string) (session, error) {
return bgp.New(logger, addr, myASN, routerID, asn, hold, password)
}