mirror of https://github.com/slackhq/nebula.git
487 lines
14 KiB
Go
487 lines
14 KiB
Go
package nebula
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import (
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"bytes"
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"context"
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"encoding/binary"
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"net/netip"
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"sync"
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"time"
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"github.com/rcrowley/go-metrics"
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"github.com/sirupsen/logrus"
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"github.com/slackhq/nebula/cert"
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"github.com/slackhq/nebula/header"
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)
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type trafficDecision int
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const (
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doNothing trafficDecision = 0
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deleteTunnel trafficDecision = 1 // delete the hostinfo on our side, do not notify the remote
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closeTunnel trafficDecision = 2 // delete the hostinfo and notify the remote
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swapPrimary trafficDecision = 3
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migrateRelays trafficDecision = 4
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tryRehandshake trafficDecision = 5
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sendTestPacket trafficDecision = 6
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)
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type connectionManager struct {
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in map[uint32]struct{}
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inLock *sync.RWMutex
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out map[uint32]struct{}
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outLock *sync.RWMutex
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// relayUsed holds which relay localIndexs are in use
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relayUsed map[uint32]struct{}
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relayUsedLock *sync.RWMutex
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hostMap *HostMap
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trafficTimer *LockingTimerWheel[uint32]
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intf *Interface
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pendingDeletion map[uint32]struct{}
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punchy *Punchy
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checkInterval time.Duration
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pendingDeletionInterval time.Duration
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metricsTxPunchy metrics.Counter
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l *logrus.Logger
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}
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func newConnectionManager(ctx context.Context, l *logrus.Logger, intf *Interface, checkInterval, pendingDeletionInterval time.Duration, punchy *Punchy) *connectionManager {
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var max time.Duration
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if checkInterval < pendingDeletionInterval {
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max = pendingDeletionInterval
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} else {
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max = checkInterval
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}
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nc := &connectionManager{
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hostMap: intf.hostMap,
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in: make(map[uint32]struct{}),
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inLock: &sync.RWMutex{},
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out: make(map[uint32]struct{}),
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outLock: &sync.RWMutex{},
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relayUsed: make(map[uint32]struct{}),
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relayUsedLock: &sync.RWMutex{},
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trafficTimer: NewLockingTimerWheel[uint32](time.Millisecond*500, max),
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intf: intf,
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pendingDeletion: make(map[uint32]struct{}),
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checkInterval: checkInterval,
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pendingDeletionInterval: pendingDeletionInterval,
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punchy: punchy,
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metricsTxPunchy: metrics.GetOrRegisterCounter("messages.tx.punchy", nil),
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l: l,
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}
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nc.Start(ctx)
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return nc
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}
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func (n *connectionManager) In(localIndex uint32) {
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n.inLock.RLock()
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// If this already exists, return
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if _, ok := n.in[localIndex]; ok {
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n.inLock.RUnlock()
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return
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}
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n.inLock.RUnlock()
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n.inLock.Lock()
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n.in[localIndex] = struct{}{}
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n.inLock.Unlock()
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}
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func (n *connectionManager) Out(localIndex uint32) {
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n.outLock.RLock()
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// If this already exists, return
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if _, ok := n.out[localIndex]; ok {
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n.outLock.RUnlock()
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return
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}
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n.outLock.RUnlock()
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n.outLock.Lock()
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n.out[localIndex] = struct{}{}
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n.outLock.Unlock()
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}
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func (n *connectionManager) RelayUsed(localIndex uint32) {
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n.relayUsedLock.RLock()
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// If this already exists, return
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if _, ok := n.relayUsed[localIndex]; ok {
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n.relayUsedLock.RUnlock()
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return
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}
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n.relayUsedLock.RUnlock()
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n.relayUsedLock.Lock()
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n.relayUsed[localIndex] = struct{}{}
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n.relayUsedLock.Unlock()
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}
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// getAndResetTrafficCheck returns if there was any inbound or outbound traffic within the last tick and
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// resets the state for this local index
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func (n *connectionManager) getAndResetTrafficCheck(localIndex uint32) (bool, bool) {
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n.inLock.Lock()
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n.outLock.Lock()
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_, in := n.in[localIndex]
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_, out := n.out[localIndex]
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delete(n.in, localIndex)
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delete(n.out, localIndex)
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n.inLock.Unlock()
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n.outLock.Unlock()
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return in, out
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}
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func (n *connectionManager) AddTrafficWatch(localIndex uint32) {
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// Use a write lock directly because it should be incredibly rare that we are ever already tracking this index
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n.outLock.Lock()
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if _, ok := n.out[localIndex]; ok {
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n.outLock.Unlock()
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return
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}
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n.out[localIndex] = struct{}{}
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n.trafficTimer.Add(localIndex, n.checkInterval)
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n.outLock.Unlock()
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}
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func (n *connectionManager) Start(ctx context.Context) {
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go n.Run(ctx)
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}
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func (n *connectionManager) Run(ctx context.Context) {
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//TODO: this tick should be based on the min wheel tick? Check firewall
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clockSource := time.NewTicker(500 * time.Millisecond)
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defer clockSource.Stop()
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p := []byte("")
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nb := make([]byte, 12, 12)
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out := make([]byte, mtu)
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for {
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select {
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case <-ctx.Done():
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return
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case now := <-clockSource.C:
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n.trafficTimer.Advance(now)
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for {
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localIndex, has := n.trafficTimer.Purge()
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if !has {
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break
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}
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n.doTrafficCheck(localIndex, p, nb, out, now)
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}
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}
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}
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}
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func (n *connectionManager) doTrafficCheck(localIndex uint32, p, nb, out []byte, now time.Time) {
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decision, hostinfo, primary := n.makeTrafficDecision(localIndex, now)
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switch decision {
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case deleteTunnel:
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if n.hostMap.DeleteHostInfo(hostinfo) {
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// Only clearing the lighthouse cache if this is the last hostinfo for this vpn ip in the hostmap
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n.intf.lightHouse.DeleteVpnIp(hostinfo.vpnIp)
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}
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case closeTunnel:
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n.intf.sendCloseTunnel(hostinfo)
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n.intf.closeTunnel(hostinfo)
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case swapPrimary:
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n.swapPrimary(hostinfo, primary)
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case migrateRelays:
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n.migrateRelayUsed(hostinfo, primary)
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case tryRehandshake:
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n.tryRehandshake(hostinfo)
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case sendTestPacket:
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n.intf.SendMessageToHostInfo(header.Test, header.TestRequest, hostinfo, p, nb, out)
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}
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n.resetRelayTrafficCheck(hostinfo)
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}
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func (n *connectionManager) resetRelayTrafficCheck(hostinfo *HostInfo) {
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if hostinfo != nil {
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n.relayUsedLock.Lock()
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defer n.relayUsedLock.Unlock()
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// No need to migrate any relays, delete usage info now.
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for _, idx := range hostinfo.relayState.CopyRelayForIdxs() {
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delete(n.relayUsed, idx)
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}
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}
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}
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func (n *connectionManager) migrateRelayUsed(oldhostinfo, newhostinfo *HostInfo) {
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relayFor := oldhostinfo.relayState.CopyAllRelayFor()
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for _, r := range relayFor {
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existing, ok := newhostinfo.relayState.QueryRelayForByIp(r.PeerIp)
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var index uint32
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var relayFrom netip.Addr
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var relayTo netip.Addr
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switch {
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case ok && existing.State == Established:
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// This relay already exists in newhostinfo, then do nothing.
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continue
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case ok && existing.State == Requested:
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// The relay exists in a Requested state; re-send the request
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index = existing.LocalIndex
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switch r.Type {
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case TerminalType:
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relayFrom = n.intf.myVpnNet.Addr()
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relayTo = existing.PeerIp
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case ForwardingType:
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relayFrom = existing.PeerIp
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relayTo = newhostinfo.vpnIp
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default:
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// should never happen
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}
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case !ok:
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n.relayUsedLock.RLock()
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if _, relayUsed := n.relayUsed[r.LocalIndex]; !relayUsed {
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// The relay hasn't been used; don't migrate it.
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n.relayUsedLock.RUnlock()
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continue
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}
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n.relayUsedLock.RUnlock()
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// The relay doesn't exist at all; create some relay state and send the request.
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var err error
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index, err = AddRelay(n.l, newhostinfo, n.hostMap, r.PeerIp, nil, r.Type, Requested)
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if err != nil {
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n.l.WithError(err).Error("failed to migrate relay to new hostinfo")
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continue
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}
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switch r.Type {
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case TerminalType:
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relayFrom = n.intf.myVpnNet.Addr()
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relayTo = r.PeerIp
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case ForwardingType:
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relayFrom = r.PeerIp
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relayTo = newhostinfo.vpnIp
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default:
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// should never happen
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}
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}
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//TODO: IPV6-WORK
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relayFromB := relayFrom.As4()
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relayToB := relayTo.As4()
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// Send a CreateRelayRequest to the peer.
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req := NebulaControl{
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Type: NebulaControl_CreateRelayRequest,
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InitiatorRelayIndex: index,
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RelayFromIp: binary.BigEndian.Uint32(relayFromB[:]),
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RelayToIp: binary.BigEndian.Uint32(relayToB[:]),
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}
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msg, err := req.Marshal()
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if err != nil {
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n.l.WithError(err).Error("failed to marshal Control message to migrate relay")
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} else {
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n.intf.SendMessageToHostInfo(header.Control, 0, newhostinfo, msg, make([]byte, 12), make([]byte, mtu))
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n.l.WithFields(logrus.Fields{
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"relayFrom": req.RelayFromIp,
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"relayTo": req.RelayToIp,
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"initiatorRelayIndex": req.InitiatorRelayIndex,
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"responderRelayIndex": req.ResponderRelayIndex,
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"vpnIp": newhostinfo.vpnIp}).
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Info("send CreateRelayRequest")
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}
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}
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}
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func (n *connectionManager) makeTrafficDecision(localIndex uint32, now time.Time) (trafficDecision, *HostInfo, *HostInfo) {
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n.hostMap.RLock()
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defer n.hostMap.RUnlock()
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hostinfo := n.hostMap.Indexes[localIndex]
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if hostinfo == nil {
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n.l.WithField("localIndex", localIndex).Debugf("Not found in hostmap")
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delete(n.pendingDeletion, localIndex)
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return doNothing, nil, nil
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}
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if n.isInvalidCertificate(now, hostinfo) {
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delete(n.pendingDeletion, hostinfo.localIndexId)
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return closeTunnel, hostinfo, nil
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}
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primary := n.hostMap.Hosts[hostinfo.vpnIp]
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mainHostInfo := true
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if primary != nil && primary != hostinfo {
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mainHostInfo = false
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}
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// Check for traffic on this hostinfo
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inTraffic, outTraffic := n.getAndResetTrafficCheck(localIndex)
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// A hostinfo is determined alive if there is incoming traffic
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if inTraffic {
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decision := doNothing
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if n.l.Level >= logrus.DebugLevel {
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hostinfo.logger(n.l).
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WithField("tunnelCheck", m{"state": "alive", "method": "passive"}).
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Debug("Tunnel status")
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}
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delete(n.pendingDeletion, hostinfo.localIndexId)
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if mainHostInfo {
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decision = tryRehandshake
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} else {
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if n.shouldSwapPrimary(hostinfo, primary) {
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decision = swapPrimary
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} else {
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// migrate the relays to the primary, if in use.
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decision = migrateRelays
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}
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}
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n.trafficTimer.Add(hostinfo.localIndexId, n.checkInterval)
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if !outTraffic {
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// Send a punch packet to keep the NAT state alive
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n.sendPunch(hostinfo)
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}
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return decision, hostinfo, primary
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}
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if _, ok := n.pendingDeletion[hostinfo.localIndexId]; ok {
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// We have already sent a test packet and nothing was returned, this hostinfo is dead
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hostinfo.logger(n.l).
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WithField("tunnelCheck", m{"state": "dead", "method": "active"}).
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Info("Tunnel status")
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delete(n.pendingDeletion, hostinfo.localIndexId)
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return deleteTunnel, hostinfo, nil
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}
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decision := doNothing
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if hostinfo != nil && hostinfo.ConnectionState != nil && mainHostInfo {
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if !outTraffic {
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// If we aren't sending or receiving traffic then its an unused tunnel and we don't to test the tunnel.
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// Just maintain NAT state if configured to do so.
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n.sendPunch(hostinfo)
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n.trafficTimer.Add(hostinfo.localIndexId, n.checkInterval)
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return doNothing, nil, nil
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}
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if n.punchy.GetTargetEverything() {
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// This is similar to the old punchy behavior with a slight optimization.
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// We aren't receiving traffic but we are sending it, punch on all known
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// ips in case we need to re-prime NAT state
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n.sendPunch(hostinfo)
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}
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if n.l.Level >= logrus.DebugLevel {
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hostinfo.logger(n.l).
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WithField("tunnelCheck", m{"state": "testing", "method": "active"}).
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Debug("Tunnel status")
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}
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// Send a test packet to trigger an authenticated tunnel test, this should suss out any lingering tunnel issues
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decision = sendTestPacket
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} else {
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if n.l.Level >= logrus.DebugLevel {
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hostinfo.logger(n.l).Debugf("Hostinfo sadness")
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}
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}
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n.pendingDeletion[hostinfo.localIndexId] = struct{}{}
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n.trafficTimer.Add(hostinfo.localIndexId, n.pendingDeletionInterval)
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return decision, hostinfo, nil
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}
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func (n *connectionManager) shouldSwapPrimary(current, primary *HostInfo) bool {
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// The primary tunnel is the most recent handshake to complete locally and should work entirely fine.
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// If we are here then we have multiple tunnels for a host pair and neither side believes the same tunnel is primary.
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// Let's sort this out.
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if current.vpnIp.Compare(n.intf.myVpnNet.Addr()) < 0 {
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// Only one side should flip primary because if both flip then we may never resolve to a single tunnel.
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// vpn ip is static across all tunnels for this host pair so lets use that to determine who is flipping.
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// The remotes vpn ip is lower than mine. I will not flip.
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return false
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}
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certState := n.intf.pki.GetCertState()
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return bytes.Equal(current.ConnectionState.myCert.Signature, certState.Certificate.Signature)
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}
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func (n *connectionManager) swapPrimary(current, primary *HostInfo) {
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n.hostMap.Lock()
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// Make sure the primary is still the same after the write lock. This avoids a race with a rehandshake.
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if n.hostMap.Hosts[current.vpnIp] == primary {
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n.hostMap.unlockedMakePrimary(current)
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}
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n.hostMap.Unlock()
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}
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// isInvalidCertificate will check if we should destroy a tunnel if pki.disconnect_invalid is true and
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// the certificate is no longer valid. Block listed certificates will skip the pki.disconnect_invalid
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// check and return true.
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func (n *connectionManager) isInvalidCertificate(now time.Time, hostinfo *HostInfo) bool {
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remoteCert := hostinfo.GetCert()
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if remoteCert == nil {
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return false
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}
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valid, err := remoteCert.VerifyWithCache(now, n.intf.pki.GetCAPool())
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if valid {
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return false
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}
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if !n.intf.disconnectInvalid.Load() && err != cert.ErrBlockListed {
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// Block listed certificates should always be disconnected
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return false
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}
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fingerprint, _ := remoteCert.Sha256Sum()
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hostinfo.logger(n.l).WithError(err).
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WithField("fingerprint", fingerprint).
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Info("Remote certificate is no longer valid, tearing down the tunnel")
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return true
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}
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func (n *connectionManager) sendPunch(hostinfo *HostInfo) {
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if !n.punchy.GetPunch() {
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// Punching is disabled
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return
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}
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if n.punchy.GetTargetEverything() {
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hostinfo.remotes.ForEach(n.hostMap.GetPreferredRanges(), func(addr netip.AddrPort, preferred bool) {
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n.metricsTxPunchy.Inc(1)
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n.intf.outside.WriteTo([]byte{1}, addr)
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})
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} else if hostinfo.remote.IsValid() {
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n.metricsTxPunchy.Inc(1)
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n.intf.outside.WriteTo([]byte{1}, hostinfo.remote)
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}
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}
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func (n *connectionManager) tryRehandshake(hostinfo *HostInfo) {
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certState := n.intf.pki.GetCertState()
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if bytes.Equal(hostinfo.ConnectionState.myCert.Signature, certState.Certificate.Signature) {
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return
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}
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n.l.WithField("vpnIp", hostinfo.vpnIp).
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WithField("reason", "local certificate is not current").
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Info("Re-handshaking with remote")
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n.intf.handshakeManager.StartHandshake(hostinfo.vpnIp, nil)
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}
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