+
+/*
+ * As it's impossible to use stream ciphers in "datagram" mode, this
+ * simple filter is designed to disengage them in DTLS. Unfortunately
+ * there is no universal way to identify stream SSL_CIPHER, so we have
+ * to explicitly list their SSL_* codes. Currently RC4 is the only one
+ * available, but if new ones emerge, they will have to be added...
+ */
+const SSL_CIPHER *dtls1_get_cipher(unsigned int u)
+ {
+ const SSL_CIPHER *ciph = ssl3_get_cipher(u);
+
+ if (ciph != NULL)
+ {
+ if (ciph->algorithm_enc == SSL_RC4)
+ return NULL;
+ }
+
+ return ciph;
+ }
+
+void dtls1_start_timer(SSL *s)
+ {
+ /* If timer is not set, initialize duration with 1 second */
+ if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0)
+ {
+ s->d1->timeout_duration = 1;
+ }
+
+ /* Set timeout to current time */
+ get_current_time(&(s->d1->next_timeout));
+
+ /* Add duration to current time */
+ s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
+ BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &(s->d1->next_timeout));
+ }
+
+struct timeval* dtls1_get_timeout(SSL *s, struct timeval* timeleft)
+ {
+ struct timeval timenow;
+
+ /* If no timeout is set, just return NULL */
+ if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0)
+ {
+ return NULL;
+ }
+
+ /* Get current time */
+ get_current_time(&timenow);
+
+ /* If timer already expired, set remaining time to 0 */
+ if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
+ (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
+ s->d1->next_timeout.tv_usec <= timenow.tv_usec))
+ {
+ memset(timeleft, 0, sizeof(struct timeval));
+ return timeleft;
+ }
+
+ /* Calculate time left until timer expires */
+ memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
+ timeleft->tv_sec -= timenow.tv_sec;
+ timeleft->tv_usec -= timenow.tv_usec;
+ if (timeleft->tv_usec < 0)
+ {
+ timeleft->tv_sec--;
+ timeleft->tv_usec += 1000000;
+ }
+
+ return timeleft;
+ }
+
+int dtls1_is_timer_expired(SSL *s)
+ {
+ struct timeval timeleft;
+
+ /* Get time left until timeout, return false if no timer running */
+ if (dtls1_get_timeout(s, &timeleft) == NULL)
+ {
+ return 0;
+ }
+
+ /* Return false if timer is not expired yet */
+ if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0)
+ {
+ return 0;
+ }
+
+ /* Timer expired, so return true */
+ return 1;
+ }
+
+void dtls1_double_timeout(SSL *s)
+ {
+ s->d1->timeout_duration *= 2;
+ if (s->d1->timeout_duration > 60)
+ s->d1->timeout_duration = 60;
+ dtls1_start_timer(s);
+ }
+
+void dtls1_stop_timer(SSL *s)
+ {
+ /* Reset everything */
+ memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
+ s->d1->timeout_duration = 1;
+ BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &(s->d1->next_timeout));
+ }
+
+static void get_current_time(struct timeval *t)
+{
+#ifdef OPENSSL_SYS_WIN32
+ struct _timeb tb;
+ _ftime(&tb);
+ t->tv_sec = (long)tb.time;
+ t->tv_usec = (long)tb.millitm * 1000;
+#elif defined(OPENSSL_SYS_VMS)
+ struct timeb tb;
+ ftime(&tb);
+ t->tv_sec = (long)tb.time;
+ t->tv_usec = (long)tb.millitm * 1000;
+#else
+ gettimeofday(t, NULL);
+#endif
+}