nebula/handshake_manager.go

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package nebula
import (
"crypto/rand"
"encoding/binary"
"fmt"
"net"
"time"
"github.com/sirupsen/logrus"
)
const (
// Total time to try a handshake = sequence of HandshakeTryInterval * HandshakeRetries
// With 100ms interval and 20 retries is 23.5 seconds
DefaultHandshakeTryInterval = time.Millisecond * 100
DefaultHandshakeRetries = 20
// DefaultHandshakeWaitRotation is the number of handshake attempts to do before starting to use other ips addresses
DefaultHandshakeWaitRotation = 5
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)
var (
defaultHandshakeConfig = HandshakeConfig{
tryInterval: DefaultHandshakeTryInterval,
retries: DefaultHandshakeRetries,
waitRotation: DefaultHandshakeWaitRotation,
}
)
type HandshakeConfig struct {
tryInterval time.Duration
retries int
waitRotation int
}
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type HandshakeManager struct {
pendingHostMap *HostMap
mainHostMap *HostMap
lightHouse *LightHouse
outside *udpConn
config HandshakeConfig
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OutboundHandshakeTimer *SystemTimerWheel
InboundHandshakeTimer *SystemTimerWheel
}
func NewHandshakeManager(tunCidr *net.IPNet, preferredRanges []*net.IPNet, mainHostMap *HostMap, lightHouse *LightHouse, outside *udpConn, config HandshakeConfig) *HandshakeManager {
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return &HandshakeManager{
pendingHostMap: NewHostMap("pending", tunCidr, preferredRanges),
mainHostMap: mainHostMap,
lightHouse: lightHouse,
outside: outside,
config: config,
OutboundHandshakeTimer: NewSystemTimerWheel(config.tryInterval, config.tryInterval*time.Duration(config.retries)),
InboundHandshakeTimer: NewSystemTimerWheel(config.tryInterval, config.tryInterval*time.Duration(config.retries)),
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}
}
func (c *HandshakeManager) Run(f EncWriter) {
clockSource := time.Tick(c.config.tryInterval)
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for now := range clockSource {
c.NextOutboundHandshakeTimerTick(now, f)
c.NextInboundHandshakeTimerTick(now)
}
}
func (c *HandshakeManager) NextOutboundHandshakeTimerTick(now time.Time, f EncWriter) {
c.OutboundHandshakeTimer.advance(now)
for {
ep := c.OutboundHandshakeTimer.Purge()
if ep == nil {
break
}
vpnIP := ep.(uint32)
index, err := c.pendingHostMap.GetIndexByVpnIP(vpnIP)
if err != nil {
continue
}
hostinfo, err := c.pendingHostMap.QueryVpnIP(vpnIP)
if err != nil {
continue
}
// If we haven't finished the handshake and we haven't hit max retries, query
// lighthouse and then send the handshake packet again.
if hostinfo.HandshakeCounter < c.config.retries && !hostinfo.HandshakeComplete {
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if hostinfo.remote == nil {
// We continue to query the lighthouse because hosts may
// come online during handshake retries. If the query
// succeeds (no error), add the lighthouse info to hostinfo
ips, err := c.lightHouse.Query(vpnIP, f)
if err == nil {
for _, ip := range ips {
hostinfo.AddRemote(ip)
}
hostinfo.ForcePromoteBest(c.mainHostMap.preferredRanges)
}
}
hostinfo.HandshakeCounter++
// We want to use the "best" calculated ip for the first 5 attempts, after that we just blindly rotate through
// all the others until we can stand up a connection.
if hostinfo.HandshakeCounter > c.config.waitRotation {
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hostinfo.rotateRemote()
}
// Ensure the handshake is ready to avoid a race in timer tick and stage 0 handshake generation
if hostinfo.HandshakeReady && hostinfo.remote != nil {
err := c.outside.WriteTo(hostinfo.HandshakePacket[0], hostinfo.remote)
if err != nil {
l.WithField("vpnIp", IntIp(vpnIP)).WithField("udpAddr", hostinfo.remote).
WithField("initiatorIndex", hostinfo.localIndexId).
WithField("remoteIndex", hostinfo.remoteIndexId).
WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).
WithError(err).Error("Failed to send handshake message")
} else {
//TODO: this log line is assuming a lot of stuff around the cached stage 0 handshake packet, we should
// keep the real packet struct around for logging purposes
l.WithField("vpnIp", IntIp(vpnIP)).WithField("udpAddr", hostinfo.remote).
WithField("initiatorIndex", hostinfo.localIndexId).
WithField("remoteIndex", hostinfo.remoteIndexId).
WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).
Info("Handshake message sent")
}
}
// Readd to the timer wheel so we continue trying wait HandshakeTryInterval * counter longer for next try
//l.Infoln("Interval: ", HandshakeTryInterval*time.Duration(hostinfo.HandshakeCounter))
c.OutboundHandshakeTimer.Add(vpnIP, c.config.tryInterval*time.Duration(hostinfo.HandshakeCounter))
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} else {
c.pendingHostMap.DeleteVpnIP(vpnIP)
c.pendingHostMap.DeleteIndex(index)
}
}
}
func (c *HandshakeManager) NextInboundHandshakeTimerTick(now time.Time) {
c.InboundHandshakeTimer.advance(now)
for {
ep := c.InboundHandshakeTimer.Purge()
if ep == nil {
break
}
index := ep.(uint32)
vpnIP, err := c.pendingHostMap.GetVpnIPByIndex(index)
if err != nil {
continue
}
c.pendingHostMap.DeleteIndex(index)
c.pendingHostMap.DeleteVpnIP(vpnIP)
}
}
func (c *HandshakeManager) AddVpnIP(vpnIP uint32) *HostInfo {
hostinfo := c.pendingHostMap.AddVpnIP(vpnIP)
// We lock here and use an array to insert items to prevent locking the
// main receive thread for very long by waiting to add items to the pending map
c.OutboundHandshakeTimer.Add(vpnIP, c.config.tryInterval)
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return hostinfo
}
func (c *HandshakeManager) DeleteVpnIP(vpnIP uint32) {
//l.Debugln("Deleting pending vpn ip :", IntIp(vpnIP))
c.pendingHostMap.DeleteVpnIP(vpnIP)
}
func (c *HandshakeManager) AddIndex(index uint32, ci *ConnectionState) (*HostInfo, error) {
hostinfo, err := c.pendingHostMap.AddIndex(index, ci)
if err != nil {
return nil, fmt.Errorf("Issue adding index: %d", index)
}
//c.mainHostMap.AddIndexHostInfo(index, hostinfo)
c.InboundHandshakeTimer.Add(index, time.Second*10)
return hostinfo, nil
}
func (c *HandshakeManager) AddIndexHostInfo(index uint32, h *HostInfo) {
c.pendingHostMap.AddIndexHostInfo(index, h)
}
func (c *HandshakeManager) DeleteIndex(index uint32) {
//l.Debugln("Deleting pending index :", index)
c.pendingHostMap.DeleteIndex(index)
}
func (c *HandshakeManager) QueryIndex(index uint32) (*HostInfo, error) {
return c.pendingHostMap.QueryIndex(index)
}
func (c *HandshakeManager) EmitStats() {
c.pendingHostMap.EmitStats("pending")
c.mainHostMap.EmitStats("main")
}
// Utility functions below
func generateIndex() (uint32, error) {
b := make([]byte, 4)
_, err := rand.Read(b)
if err != nil {
l.Errorln(err)
return 0, err
}
index := binary.BigEndian.Uint32(b)
if l.Level >= logrus.DebugLevel {
l.WithField("index", index).
Debug("Generated index")
}
return index, nil
}