Added ratelimiting of handshake messages

This commit is contained in:
Mathias Hall-Andersen 2017-07-11 18:48:29 +02:00
parent 9c4acb9f35
commit c273078376
5 changed files with 248 additions and 5 deletions

View File

@ -31,9 +31,10 @@ type Device struct {
signal struct {
stop chan struct{}
}
underLoad int32 // used as an atomic bool
peers map[NoisePublicKey]*Peer
mac MACStateDevice
underLoad int32 // used as an atomic bool
ratelimiter Ratelimiter
peers map[NoisePublicKey]*Peer
mac MACStateDevice
}
func (device *Device) SetPrivateKey(sk NoisePrivateKey) {
@ -66,6 +67,7 @@ func NewDevice(tun TUNDevice, logLevel int) *Device {
device.mtu = tun.MTU()
device.peers = make(map[NoisePublicKey]*Peer)
device.indices.Init()
device.ratelimiter.Init()
device.routingTable.Reset()
// listen
@ -99,6 +101,7 @@ func NewDevice(tun TUNDevice, logLevel int) *Device {
go device.RoutineReadFromTUN(tun)
go device.RoutineReceiveIncomming()
go device.RoutineWriteToTUN(tun)
go device.ratelimiter.RoutineGarbageCollector(device.signal.stop)
return device
}

140
src/ratelimiter.go Normal file
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@ -0,0 +1,140 @@
package main
/* Implementation of the ratelimited form the linux kernel version
*
*
*
*/
import (
"net"
"sync"
"time"
)
const (
RatelimiterPacketsPerSecond = 20
RatelimiterPacketsBurstable = 5
RatelimiterGarbageCollectTime = time.Second
RatelimiterPacketCost = 1000000000 / RatelimiterPacketsPerSecond
RatelimiterMaxTokens = RatelimiterPacketCost * RatelimiterPacketsBurstable
)
type RatelimiterEntry struct {
mutex sync.Mutex
lastTime time.Time
tokens int64
}
type Ratelimiter struct {
mutex sync.RWMutex
lastGarbageCollect time.Time
tableIPv4 map[[net.IPv4len]byte]*RatelimiterEntry
tableIPv6 map[[net.IPv6len]byte]*RatelimiterEntry
}
func (rate *Ratelimiter) Init() {
rate.mutex.Lock()
defer rate.mutex.Unlock()
rate.tableIPv4 = make(map[[net.IPv4len]byte]*RatelimiterEntry)
rate.tableIPv6 = make(map[[net.IPv6len]byte]*RatelimiterEntry)
rate.lastGarbageCollect = time.Now()
}
func (rate *Ratelimiter) GarbageCollectEntries() {
rate.mutex.Lock()
// remove unused IPv4 entries
for key, entry := range rate.tableIPv4 {
entry.mutex.Lock()
if time.Now().Sub(entry.lastTime) > RatelimiterGarbageCollectTime {
delete(rate.tableIPv4, key)
}
entry.mutex.Unlock()
}
// remove unused IPv6 entries
for key, entry := range rate.tableIPv6 {
entry.mutex.Lock()
if time.Now().Sub(entry.lastTime) > RatelimiterGarbageCollectTime {
delete(rate.tableIPv6, key)
}
entry.mutex.Unlock()
}
rate.mutex.Unlock()
}
func (rate *Ratelimiter) RoutineGarbageCollector(stop chan struct{}) {
timer := time.NewTimer(time.Second)
for {
select {
case <-stop:
return
case <-timer.C:
rate.GarbageCollectEntries()
timer.Reset(time.Second)
}
}
}
func (rate *Ratelimiter) Allow(ip net.IP) bool {
var entry *RatelimiterEntry
var KeyIPv4 [net.IPv4len]byte
var KeyIPv6 [net.IPv6len]byte
// lookup entry
IPv4 := ip.To4()
IPv6 := ip.To16()
rate.mutex.RLock()
if IPv4 != nil {
copy(KeyIPv4[:], IPv4)
entry = rate.tableIPv4[KeyIPv4]
} else {
copy(KeyIPv6[:], IPv6)
entry = rate.tableIPv6[KeyIPv6]
}
rate.mutex.RUnlock()
// make new entry if not found
if entry == nil {
rate.mutex.Lock()
entry = new(RatelimiterEntry)
entry.tokens = RatelimiterMaxTokens - RatelimiterPacketCost
entry.lastTime = time.Now()
if IPv4 != nil {
rate.tableIPv4[KeyIPv4] = entry
} else {
rate.tableIPv6[KeyIPv6] = entry
}
rate.mutex.Unlock()
return true
}
// add tokens to entry
entry.mutex.Lock()
now := time.Now()
entry.tokens += now.Sub(entry.lastTime).Nanoseconds()
entry.lastTime = now
if entry.tokens > RatelimiterMaxTokens {
entry.tokens = RatelimiterMaxTokens
}
// subtract cost of packet
if entry.tokens > RatelimiterPacketCost {
entry.tokens -= RatelimiterPacketCost
entry.mutex.Unlock()
return true
}
entry.mutex.Unlock()
return false
}

98
src/ratelimiter_test.go Normal file
View File

@ -0,0 +1,98 @@
package main
import (
"net"
"testing"
"time"
)
type RatelimiterResult struct {
allowed bool
text string
wait time.Duration
}
func TestRatelimiter(t *testing.T) {
var ratelimiter Ratelimiter
var expectedResults []RatelimiterResult
Nano := func(nano int64) time.Duration {
return time.Nanosecond * time.Duration(nano)
}
Add := func(res RatelimiterResult) {
expectedResults = append(
expectedResults,
res,
)
}
for i := 0; i < RatelimiterPacketsBurstable; i++ {
Add(RatelimiterResult{
allowed: true,
text: "inital burst",
})
}
Add(RatelimiterResult{
allowed: false,
text: "after burst",
})
Add(RatelimiterResult{
allowed: true,
wait: Nano(time.Second.Nanoseconds() / RatelimiterPacketsPerSecond),
text: "filling tokens for single packet",
})
Add(RatelimiterResult{
allowed: false,
text: "not having refilled enough",
})
Add(RatelimiterResult{
allowed: true,
wait: 2 * Nano(time.Second.Nanoseconds()/RatelimiterPacketsPerSecond),
text: "filling tokens for two packet burst",
})
Add(RatelimiterResult{
allowed: true,
text: "second packet in 2 packet burst",
})
Add(RatelimiterResult{
allowed: false,
text: "packet following 2 packet burst",
})
ips := []net.IP{
net.ParseIP("127.0.0.1"),
net.ParseIP("192.168.1.1"),
net.ParseIP("172.167.2.3"),
net.ParseIP("97.231.252.215"),
net.ParseIP("248.97.91.167"),
net.ParseIP("188.208.233.47"),
net.ParseIP("104.2.183.179"),
net.ParseIP("72.129.46.120"),
net.ParseIP("2001:0db8:0a0b:12f0:0000:0000:0000:0001"),
net.ParseIP("f5c2:818f:c052:655a:9860:b136:6894:25f0"),
net.ParseIP("b2d7:15ab:48a7:b07c:a541:f144:a9fe:54fc"),
net.ParseIP("a47b:786e:1671:a22b:d6f9:4ab0:abc7:c918"),
net.ParseIP("ea1e:d155:7f7a:98fb:2bf5:9483:80f6:5445"),
net.ParseIP("3f0e:54a2:f5b4:cd19:a21d:58e1:3746:84c4"),
}
ratelimiter.Init()
for i, res := range expectedResults {
time.Sleep(res.wait)
for _, ip := range ips {
allowed := ratelimiter.Allow(ip)
if allowed != res.allowed {
t.Fatal("Test failed for", ip.String(), ", on:", i, "(", res.text, ")", "expected:", res.allowed, "got:", allowed)
}
}
}
}

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@ -319,6 +319,10 @@ func (device *Device) RoutineHandshake() {
// ratelimit
if !device.ratelimiter.Allow(elem.source.IP) {
return
}
// handle messages
switch elem.msgType {

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@ -9,8 +9,6 @@ import (
*
*/
/* Copyright (C) 2015-2017 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. */
func TestReplay(t *testing.T) {
var filter ReplayFilter