Add options to set custom replay detector

Support using custom implementation of replay detector.

Author: at-wat

option.go

@@ -50,6 +50,22 @@ func SRTCPNoReplayProtection() ContextOption {
 	}
 }
 
+// SRTPReplayDetectorFactory sets custom SRTP replay detector.
+func SRTPReplayDetectorFactory(fn func() replaydetector.ReplayDetector) ContextOption { // nolint:revive
+	return func(c *Context) error {
+		c.newSRTPReplayDetector = fn
+		return nil
+	}
+}
+
+// SRTCPReplayDetectorFactory sets custom SRTCP replay detector.
+func SRTCPReplayDetectorFactory(fn func() replaydetector.ReplayDetector) ContextOption {
+	return func(c *Context) error {
+		c.newSRTCPReplayDetector = fn
+		return nil
+	}
+}
+
 type nopReplayDetector struct{}
 
 func (s *nopReplayDetector) Check(uint64) (func(), bool) {

srtcp_test.go

@@ -10,6 +10,7 @@ import (
 	"testing"
 
 	"github.com/pion/rtcp"
+	"github.com/pion/transport/v2/replaydetector"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -570,3 +571,26 @@ func TestRTCPMaxPackets(t *testing.T) {
 		})
 	}
 }
+
+func TestRTCPReplayDetectorFactory(t *testing.T) {
+	assert := assert.New(t)
+	testCase := rtcpTestCases()["AEAD_AES_128_GCM"]
+	data := testCase.packets[0]
+
+	var cntFactory int
+	decryptContext, err := CreateContext(
+		testCase.masterKey, testCase.masterSalt, testCase.algo,
+		SRTCPReplayDetectorFactory(func() replaydetector.ReplayDetector {
+			cntFactory++
+			return &nopReplayDetector{}
+		}),
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err := decryptContext.DecryptRTCP(nil, data.encrypted, nil); err != nil {
+		t.Fatal(err)
+	}
+	assert.Equal(1, cntFactory)
+}

srtp_test.go

@@ -9,6 +9,7 @@ import (
 	"testing"
 
 	"github.com/pion/rtp"
+	"github.com/pion/transport/v2/replaydetector"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -462,6 +463,37 @@ func TestRTPReplayProtection(t *testing.T) {
 	t.Run("GCM", func(t *testing.T) { testRTPReplayProtection(t, profileGCM) })
 }
 
+func TestRTPReplayDetectorFactory(t *testing.T) {
+	assert := assert.New(t)
+	profile := profileCTR
+	data := rtpTestCases()[0]
+
+	var cntFactory int
+	decryptContext, err := buildTestContext(
+		profile, SRTPReplayDetectorFactory(func() replaydetector.ReplayDetector {
+			cntFactory++
+			return &nopReplayDetector{}
+		}),
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	pkt := &rtp.Packet{
+		Payload: data.encrypted(profile),
+		Header:  rtp.Header{SequenceNumber: data.sequenceNumber},
+	}
+	in, err := pkt.Marshal()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err := decryptContext.DecryptRTP(nil, in, nil); err != nil {
+		t.Fatal(err)
+	}
+	assert.Equal(1, cntFactory)
+}
+
 func benchmarkEncryptRTP(b *testing.B, profile ProtectionProfile, size int) {
 	encryptContext, err := buildTestContext(profile)
 	if err != nil {