add configurable punching delay because of race-condition-y conntracks (#210)

* add configurable punching delay because of race-condition-y conntracks

* add changelog

* fix tests

* only do one punch per query

* Coalesce punchy config

* It is not is not set

* Add tests

Co-authored-by: Nate Brown <nbrown.us@gmail.com>
This commit is contained in:
Ryan Huber 2020-03-27 11:26:39 -07:00 committed by GitHub
parent add1b21777
commit 1297090af3
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GPG Key ID: 4AEE18F83AFDEB23
9 changed files with 116 additions and 18 deletions

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@ -7,6 +7,21 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
## [Unreleased]
### Changed
- Added a delay to punching via lighthouse signal to deal with race conditions in some linux conntrack implementations.
See deprecated, this also adds a new `punchy.delay` option that defaults to `1s`
### Deprecated
- `punchy`, `punch_back` configuration options have been collapsed under the now top level `punchy` config directive.
`punchy.punch` - This is the old `punchy` option. Should we perform NAT hole punching (default false)?
`punchy.respond` - This is the old `punch_back` option, Should we respond to hole punching by hole punching back (default false)?
## [1.1.0] - 2020-01-17
### Added

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@ -217,6 +217,10 @@ func (c *Config) Get(k string) interface{} {
return c.get(k, c.Settings)
}
func (c *Config) IsSet(k string) bool {
return c.get(k, c.Settings) != nil
}
func (c *Config) get(k string, v interface{}) interface{} {
parts := strings.Split(k, ".")
for _, p := range parts {

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@ -28,7 +28,7 @@ func Test_NewConnectionManagerTest(t *testing.T) {
rawCertificateNoKey: []byte{},
}
lh := NewLightHouse(false, 0, []uint32{}, 1000, 0, &udpConn{}, false)
lh := NewLightHouse(false, 0, []uint32{}, 1000, 0, &udpConn{}, false, 1)
ifce := &Interface{
hostMap: hostMap,
inside: &Tun{},
@ -91,7 +91,7 @@ func Test_NewConnectionManagerTest2(t *testing.T) {
rawCertificateNoKey: []byte{},
}
lh := NewLightHouse(false, 0, []uint32{}, 1000, 0, &udpConn{}, false)
lh := NewLightHouse(false, 0, []uint32{}, 1000, 0, &udpConn{}, false, 1)
ifce := &Interface{
hostMap: hostMap,
inside: &Tun{},

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@ -55,11 +55,17 @@ listen:
#read_buffer: 10485760
#write_buffer: 10485760
# Punchy continues to punch inbound/outbound at a regular interval to avoid expiration of firewall nat mappings
punchy: true
# punch_back means that a node you are trying to reach will connect back out to you if your hole punching fails
# this is extremely useful if one node is behind a difficult nat, such as symmetric
#punch_back: true
punchy:
# Continues to punch inbound/outbound at a regular interval to avoid expiration of firewall nat mappings
punch: true
# respond means that a node you are trying to reach will connect back out to you if your hole punching fails
# this is extremely useful if one node is behind a difficult nat, such as a symmetric NAT
# Default is false
#respond: true
# delays a punch response for misbehaving NATs, default is 1 second, respond must be true to take effect
#delay: 1s
# Cipher allows you to choose between the available ciphers for your network.
# IMPORTANT: this value must be identical on ALL NODES/LIGHTHOUSES. We do not/will not support use of different ciphers simultaneously!

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@ -26,6 +26,7 @@ type LightHouse struct {
interval int
nebulaPort int
punchBack bool
punchDelay time.Duration
}
type EncWriter interface {
@ -33,7 +34,7 @@ type EncWriter interface {
SendMessageToAll(t NebulaMessageType, st NebulaMessageSubType, vpnIp uint32, p, nb, out []byte)
}
func NewLightHouse(amLighthouse bool, myIp uint32, ips []uint32, interval int, nebulaPort int, pc *udpConn, punchBack bool) *LightHouse {
func NewLightHouse(amLighthouse bool, myIp uint32, ips []uint32, interval int, nebulaPort int, pc *udpConn, punchBack bool, punchDelay time.Duration) *LightHouse {
h := LightHouse{
amLighthouse: amLighthouse,
myIp: myIp,
@ -44,6 +45,7 @@ func NewLightHouse(amLighthouse bool, myIp uint32, ips []uint32, interval int, n
interval: interval,
punchConn: pc,
punchBack: punchBack,
punchDelay: punchDelay,
}
for _, ip := range ips {
@ -328,10 +330,8 @@ func (lh *LightHouse) HandleRequest(rAddr *udpAddr, vpnIp uint32, p []byte, c *c
for _, a := range n.Details.IpAndPorts {
vpnPeer := NewUDPAddr(a.Ip, uint16(a.Port))
go func() {
for i := 0; i < 5; i++ {
time.Sleep(lh.punchDelay)
lh.punchConn.WriteTo(empty, vpnPeer)
time.Sleep(time.Second * 1)
}
}()
l.Debugf("Punching %s on %d for %s", IntIp(a.Ip), a.Port, IntIp(n.Details.VpnIp))

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@ -52,7 +52,7 @@ func Test_lhStaticMapping(t *testing.T) {
udpServer, _ := NewListener("0.0.0.0", 0, true)
meh := NewLightHouse(true, 1, []uint32{ip2int(lh1IP)}, 10, 10003, udpServer, false)
meh := NewLightHouse(true, 1, []uint32{ip2int(lh1IP)}, 10, 10003, udpServer, false, 1)
meh.AddRemote(ip2int(lh1IP), NewUDPAddr(ip2int(lh1IP), uint16(4242)), true)
err := meh.ValidateLHStaticEntries()
assert.Nil(t, err)
@ -60,7 +60,7 @@ func Test_lhStaticMapping(t *testing.T) {
lh2 := "10.128.0.3"
lh2IP := net.ParseIP(lh2)
meh = NewLightHouse(true, 1, []uint32{ip2int(lh1IP), ip2int(lh2IP)}, 10, 10003, udpServer, false)
meh = NewLightHouse(true, 1, []uint32{ip2int(lh1IP), ip2int(lh2IP)}, 10, 10003, udpServer, false, 1)
meh.AddRemote(ip2int(lh1IP), NewUDPAddr(ip2int(lh1IP), uint16(4242)), true)
err = meh.ValidateLHStaticEntries()
assert.EqualError(t, err, "Lighthouse 10.128.0.3 does not have a static_host_map entry")

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@ -177,8 +177,8 @@ func Main(configPath string, configTest bool, buildVersion string) {
go hostMap.Promoter(config.GetInt("promoter.interval"))
*/
punchy := config.GetBool("punchy", false)
if punchy == true {
punchy := NewPunchyFromConfig(config)
if punchy.Punch {
l.Info("UDP hole punching enabled")
go hostMap.Punchy(udpServer)
}
@ -193,7 +193,6 @@ func Main(configPath string, configTest bool, buildVersion string) {
port = int(uPort.Port)
}
punchBack := config.GetBool("punch_back", false)
amLighthouse := config.GetBool("lighthouse.am_lighthouse", false)
// warn if am_lighthouse is enabled but upstream lighthouses exists
@ -222,7 +221,8 @@ func Main(configPath string, configTest bool, buildVersion string) {
config.GetInt("lighthouse.interval", 10),
port,
udpServer,
punchBack,
punchy.Respond,
punchy.Delay,
)
//TODO: Move all of this inside functions in lighthouse.go

30
punchy.go Normal file
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@ -0,0 +1,30 @@
package nebula
import "time"
type Punchy struct {
Punch bool
Respond bool
Delay time.Duration
}
func NewPunchyFromConfig(c *Config) *Punchy {
p := &Punchy{}
if c.IsSet("punchy.punch") {
p.Punch = c.GetBool("punchy.punch", false)
} else {
// Deprecated fallback
p.Punch = c.GetBool("punchy", false)
}
if c.IsSet("punchy.respond") {
p.Respond = c.GetBool("punchy.respond", false)
} else {
// Deprecated fallback
p.Respond = c.GetBool("punch_back", false)
}
p.Delay = c.GetDuration("punchy.delay", time.Second)
return p
}

43
punchy_test.go Normal file
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@ -0,0 +1,43 @@
package nebula
import (
"github.com/stretchr/testify/assert"
"testing"
"time"
)
func TestNewPunchyFromConfig(t *testing.T) {
c := NewConfig()
// Test defaults
p := NewPunchyFromConfig(c)
assert.Equal(t, false, p.Punch)
assert.Equal(t, false, p.Respond)
assert.Equal(t, time.Second, p.Delay)
// punchy deprecation
c.Settings["punchy"] = true
p = NewPunchyFromConfig(c)
assert.Equal(t, true, p.Punch)
// punchy.punch
c.Settings["punchy"] = map[interface{}]interface{}{"punch": true}
p = NewPunchyFromConfig(c)
assert.Equal(t, true, p.Punch)
// punch_back deprecation
c.Settings["punch_back"] = true
p = NewPunchyFromConfig(c)
assert.Equal(t, true, p.Respond)
// punchy.respond
c.Settings["punchy"] = map[interface{}]interface{}{"respond": true}
c.Settings["punch_back"] = false
p = NewPunchyFromConfig(c)
assert.Equal(t, true, p.Respond)
// punchy.delay
c.Settings["punchy"] = map[interface{}]interface{}{"delay": "1m"}
p = NewPunchyFromConfig(c)
assert.Equal(t, time.Minute, p.Delay)
}