VMess inbound: Optimize replay filter (#5562)

And https://github.com/XTLS/Xray-core/pull/5562#issuecomment-3765387903

common/antireplay/antireplay.go

@@ -1,6 +0,0 @@
-package antireplay
-
-type GeneralizedReplayFilter interface {
-	Interval() int64
-	Check(sum []byte) bool
-}

common/antireplay/antireplay_test.go

@@ -0,0 +1,33 @@
+package antireplay
+
+import (
+	"bufio"
+	"crypto/rand"
+	"testing"
+)
+
+func BenchmarkMapFilter(b *testing.B) {
+	filter := NewMapFilter[[16]byte](120)
+	var sample [16]byte
+	reader := bufio.NewReader(rand.Reader)
+	reader.Read(sample[:])
+	b.ResetTimer()
+	for range b.N {
+		reader.Read(sample[:])
+		filter.Check(sample)
+	}
+}
+
+func TestMapFilter(t *testing.T) {
+	filter := NewMapFilter[[16]byte](120)
+	var sample [16]byte
+	rand.Read(sample[:])
+	filter.Check(sample)
+	if filter.Check(sample) {
+		t.Error("Unexpected true negative")
+	}
+	sample[0]++
+	if !filter.Check(sample) {
+		t.Error("Unexpected false positive")
+	}
+}

common/antireplay/bloomring.go

@@ -1,36 +0,0 @@
-package antireplay
-
-import (
-	"sync"
-
-	ss_bloomring "github.com/v2fly/ss-bloomring"
-)
-
-type BloomRing struct {
-	*ss_bloomring.BloomRing
-	lock *sync.Mutex
-}
-
-func (b BloomRing) Interval() int64 {
-	return 9999999
-}
-
-func (b BloomRing) Check(sum []byte) bool {
-	b.lock.Lock()
-	defer b.lock.Unlock()
-	if b.Test(sum) {
-		return false
-	}
-	b.Add(sum)
-	return true
-}
-
-func NewBloomRing() BloomRing {
-	const (
-		DefaultSFCapacity = 1e6
-		// FalsePositiveRate
-		DefaultSFFPR  = 1e-6
-		DefaultSFSlot = 10
-	)
-	return BloomRing{ss_bloomring.NewBloomRing(DefaultSFSlot, DefaultSFCapacity, DefaultSFFPR), &sync.Mutex{}}
-}

common/antireplay/mapfilter.go

@@ -0,0 +1,46 @@
+package antireplay
+
+import (
+	"sync"
+	"time"
+)
+
+// ReplayFilter checks for replay attacks.
+type ReplayFilter[T comparable] struct {
+	lock      sync.Mutex
+	poolA     map[T]struct{}
+	poolB     map[T]struct{}
+	interval  time.Duration
+	lastClean time.Time
+}
+
+// NewMapFilter create a new filter with specifying the expiration time interval in seconds.
+func NewMapFilter[T comparable](interval int64) *ReplayFilter[T] {
+	filter := &ReplayFilter[T]{
+		poolA:     make(map[T]struct{}),
+		poolB:     make(map[T]struct{}),
+		interval:  time.Duration(interval) * time.Second,
+		lastClean: time.Now(),
+	}
+	return filter
+}
+
+// Check determines if there are duplicate records.
+func (filter *ReplayFilter[T]) Check(sum T) bool {
+	filter.lock.Lock()
+	defer filter.lock.Unlock()
+
+	now := time.Now()
+	if now.Sub(filter.lastClean) >= filter.interval {
+		filter.poolB = filter.poolA
+		filter.poolA = make(map[T]struct{})
+		filter.lastClean = now
+	}
+
+	_, existsA := filter.poolA[sum]
+	_, existsB := filter.poolB[sum]
+	if !existsA && !existsB {
+		filter.poolA[sum] = struct{}{}
+	}
+	return !(existsA || existsB)
+}

common/antireplay/replayfilter.go

@@ -1,58 +0,0 @@
-package antireplay
-
-import (
-	"sync"
-	"time"
-
-	cuckoo "github.com/seiflotfy/cuckoofilter"
-)
-
-const replayFilterCapacity = 100000
-
-// ReplayFilter checks for replay attacks.
-type ReplayFilter struct {
-	lock     sync.Mutex
-	poolA    *cuckoo.Filter
-	poolB    *cuckoo.Filter
-	poolSwap bool
-	lastSwap int64
-	interval int64
-}
-
-// NewReplayFilter create a new filter with specifying the expiration time interval in seconds.
-func NewReplayFilter(interval int64) *ReplayFilter {
-	filter := &ReplayFilter{}
-	filter.interval = interval
-	return filter
-}
-
-// Interval in second for expiration time for duplicate records.
-func (filter *ReplayFilter) Interval() int64 {
-	return filter.interval
-}
-
-// Check determines if there are duplicate records.
-func (filter *ReplayFilter) Check(sum []byte) bool {
-	filter.lock.Lock()
-	defer filter.lock.Unlock()
-
-	now := time.Now().Unix()
-	if filter.lastSwap == 0 {
-		filter.lastSwap = now
-		filter.poolA = cuckoo.NewFilter(replayFilterCapacity)
-		filter.poolB = cuckoo.NewFilter(replayFilterCapacity)
-	}
-
-	elapsed := now - filter.lastSwap
-	if elapsed >= filter.Interval() {
-		if filter.poolSwap {
-			filter.poolA.Reset()
-		} else {
-			filter.poolB.Reset()
-		}
-		filter.poolSwap = !filter.poolSwap
-		filter.lastSwap = now
-	}
-
-	return filter.poolA.InsertUnique(sum) && filter.poolB.InsertUnique(sum)
-}