Do not wait for socket to be ready when sending DTLS data.

src/tlslib.c

@@ -63,6 +63,31 @@ ssize_t tls_send(gnutls_session_t session, const void *data,
 	return data_size;
 }
 
+/* Same as tls_send() but will not retry on EAGAIN errors */
+ssize_t tls_send_nowait(gnutls_session_t session, const void *data,
+			size_t data_size)
+{
+	int ret;
+	int left = data_size;
+	const uint8_t* p = data;
+
+	while(left > 0) {
+		ret = gnutls_record_send(session, p, data_size);
+		if (ret < 0 && ret != GNUTLS_E_INTERRUPTED) {
+			if (ret == GNUTLS_E_AGAIN)
+			  return data_size;
+			return ret;
+		}
+	
+		if (ret > 0) {
+			left -= ret;
+			p += ret;
+		}
+	}
+	
+	return data_size;
+}
+
 ssize_t tls_send_file(gnutls_session_t session, const char *file)
 {
 FILE* fp;

src/tlslib.h

@@ -14,6 +14,8 @@ int __attribute__ ((format(printf, 2, 3)))
 ssize_t tls_recv(gnutls_session_t session, void *data, size_t data_size);
 ssize_t tls_send(gnutls_session_t session, const void *data,
 			size_t data_size);
+ssize_t tls_send_nowait(gnutls_session_t session, const void *data,
+			size_t data_size);
 
 void tls_cork(gnutls_session_t session);
 int tls_uncork(gnutls_session_t session);

src/worker-vpn.c

@@ -1090,7 +1090,7 @@ socklen_t sl;
 			if (ws->udp_state == UP_ACTIVE) {
 				ws->buffer[7] = AC_PKT_DATA;
 
-				ret = tls_send(ws->dtls_session, ws->buffer + 7, l + 1);
+				ret = tls_send_nowait(ws->dtls_session, ws->buffer + 7, l + 1);
 				GNUTLS_FATAL_ERR(ret);
 
 				if (ret == GNUTLS_E_LARGE_PACKET) {