work on dtls

FossilOrigin-Name: 8b02ed99e3287eaa044a4f4c6c8b61ab6f1a14983db99accb43b5be8425befe8

src/cw/conn_q_wait_packet.c

@@ -0,0 +1,20 @@
+#include <errno.h>
+#include <time.h>
+
+#include "conn.h"
+
+int conn_q_wait_packet(struct conn * conn, int seconds)
+{
+
+	struct timespec timespec;
+	clock_gettime(CLOCK_REALTIME,&timespec);
+	timespec.tv_sec+=seconds;
+
+
+	/* wait one second to get a packet */
+	if (sem_timedwait(&conn->q_sem,&timespec)==-1){
+		return EAGAIN;
+	};
+
+	return 0;
+}