Add replay protection setting to SettingEngine

Set windows size of each protocol by:
- SetDTLSReplayProtectionWindow
- SetSRTPReplayProtectionWindow
- SetSRTCPReplayProtectionWindow

settingengine.go

@@ -43,6 +43,11 @@ type SettingEngine struct {
 		UsernameFragment               string
 		Password                       string
 	}
+	replayProtection struct {
+		DTLS  *uint
+		SRTP  *uint
+		SRTCP *uint
+	}
 	answeringDTLSRole                         DTLSRole
 	disableCertificateFingerprintVerification bool
 	vnet                                      *vnet.Net
@@ -205,3 +210,18 @@ func (e *SettingEngine) SetICECredentials(usernameFragment, password string) {
 func (e *SettingEngine) DisableCertificateFingerprintVerification(isDisabled bool) {
 	e.disableCertificateFingerprintVerification = isDisabled
 }
+
+// SetDTLSReplayProtectionWindow sets a replay attack protection window size of DTLS connection.
+func (e *SettingEngine) SetDTLSReplayProtectionWindow(n uint) {
+	e.replayProtection.DTLS = &n
+}
+
+// SetSRTPReplayProtectionWindow sets a replay attack protection window size of SRTP session.
+func (e *SettingEngine) SetSRTPReplayProtectionWindow(n uint) {
+	e.replayProtection.SRTP = &n
+}
+
+// SetSRTCPReplayProtectionWindow sets a replay attack protection window size of SRTCP session.
+func (e *SettingEngine) SetSRTCPReplayProtectionWindow(n uint) {
+	e.replayProtection.SRTCP = &n
+}