diff --git a/inc/gquic.h b/inc/gquic.h
index a24f45f..133912c 100644
--- a/inc/gquic.h
+++ b/inc/gquic.h
@@ -90,7 +90,7 @@ struct _quic_info
 
 //buff_len minimun 32bytes
 int quic_version_int2string(unsigned int version, char *buff, int buff_len);
-//ret: 0: not quic, >0: quic
-int quic_protocol_identify(struct streaminfo *a_stream, void *a_packet, char *out_sni, int out_sni_len);
+//ret: 0: not quic, >0: quic version
+unsigned int quic_protocol_identify(struct streaminfo *a_stream, void *a_packet, char *out_sni, int *out_sni_len, char *out_ua, int *out_ua_len);
 
 #endif /* SRC_GQUIC_H_ */
diff --git a/src/gquic_process.cpp b/src/gquic_process.cpp
index 3d1183d..da1e810 100644
--- a/src/gquic_process.cpp
+++ b/src/gquic_process.cpp
@@ -20,6 +20,10 @@
 #define	PRINTADDR(a, b)	((b)<RLOG_LV_FATAL ? printaddr(&(a->addr), a->threadnum) : "")
 #endif
 
+#ifndef MIN
+#define MIN(a, b)  	(((a) < (b)) ? (a) : (b))
+#endif
+
 const unsigned char PCAP_FILE_HEAD[24] = {0xD4, 0xC3, 0xB2, 0xA1, 0x02, 0x00, 0x04, 0x00,
 								 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 								 0xFF, 0xFF, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00};
@@ -1350,18 +1354,17 @@ int quic_process(struct streaminfo *pstream, struct _quic_context* _context, int
 	return APP_STATE_DROPME;;
 }
 
-
-int quic_protocol_identify(struct streaminfo *a_stream, void *a_packet, char *out_sni, int out_sni_len)
+unsigned int quic_protocol_identify(struct streaminfo *a_stream, void *a_packet, char *out_sni, int *out_sni_len, char *out_ua, int *out_ua_len)
 {
 	int ret=APP_STATE_GIVEME;
-	int sni_len=0,len=-1;
+	int len=0;
 	void *pme=NULL;
-	char *sni=NULL;
 	struct _quic_context *_context=NULL;
+	unsigned int quic_version=QUIC_VERSION_UNKNOWN;
 
 	if(!is_quic_port(a_stream))
 	{
-		return len;
+		return quic_version;
 	}
 	
 	quic_init_stream(&pme, a_stream->threadnum);
@@ -1374,26 +1377,30 @@ int quic_protocol_identify(struct streaminfo *a_stream, void *a_packet, char *ou
 		{
 			if(_context->quic_info.client_hello->sni_idx!=0xFF)
 			{
-				sni=(char *)(_context->quic_info.client_hello->ext_tags[_context->quic_info.client_hello->sni_idx].value);
-				sni_len=_context->quic_info.client_hello->ext_tags[_context->quic_info.client_hello->sni_idx].length;
-				len= sni_len>(out_sni_len-1) ? (out_sni_len-1) : sni_len;
-				memcpy(out_sni, sni, len);
+				len=MIN((int)_context->quic_info.client_hello->ext_tags[_context->quic_info.client_hello->sni_idx].length, (*out_sni_len)-1);
+				memcpy(out_sni, _context->quic_info.client_hello->ext_tags[_context->quic_info.client_hello->sni_idx].value, len);
+				(*out_sni_len)=len;
 			}
-			else
+
+			if(_context->quic_info.client_hello->ua_idx!=0xFF)
 			{
-				len=0;
+				len=MIN((int)_context->quic_info.client_hello->ext_tags[_context->quic_info.client_hello->ua_idx].length, (*out_ua_len)-1);
+				memcpy(out_ua, _context->quic_info.client_hello->ext_tags[_context->quic_info.client_hello->ua_idx].value, len);
+				(*out_ua_len)=len;
 			}
+			
+			quic_version=_context->quic_info.quic_hdr.quic_version;
 		}
 		else
 		{
 			if(_context->is_quic==TRUE)
 			{
-				len=0;
+				quic_version=_context->quic_info.quic_hdr.quic_version;
 			}
 		}
 	}
 
 	quic_release_stream(&pme, a_stream->threadnum);
 
-	return len;
+	return quic_version;
 }