00001 /* 00002 * Copyright (C) 2001-2004 by egnite Software GmbH. All rights reserved. 00003 * 00004 * Redistribution and use in source and binary forms, with or without 00005 * modification, are permitted provided that the following conditions 00006 * are met: 00007 * 00008 * 1. Redistributions of source code must retain the above copyright 00009 * notice, this list of conditions and the following disclaimer. 00010 * 2. Redistributions in binary form must reproduce the above copyright 00011 * notice, this list of conditions and the following disclaimer in the 00012 * documentation and/or other materials provided with the distribution. 00013 * 3. Neither the name of the copyright holders nor the names of 00014 * contributors may be used to endorse or promote products derived 00015 * from this software without specific prior written permission. 00016 * 00017 * THIS SOFTWARE IS PROVIDED BY EGNITE SOFTWARE GMBH AND CONTRIBUTORS 00018 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 00019 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 00020 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL EGNITE 00021 * SOFTWARE GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 00022 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 00023 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 00024 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 00025 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 00026 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 00027 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 00028 * SUCH DAMAGE. 00029 * 00030 * For additional information see http://www.ethernut.de/ 00031 * 00032 */ 00033 00034 /* 00035 * $Log: tcputil.c,v $ 00036 * Revision 1.3 2008/07/27 11:43:22 haraldkipp 00037 * Configurable TCP retransmissions. 00038 * 00039 * Revision 1.2 2004/07/30 19:54:46 drsung 00040 * Some code of TCP stack redesigned. Round trip time calculation is now 00041 * supported. Fixed several bugs in TCP state machine. Now TCP connections 00042 * should be more reliable under heavy traffic or poor physical connections. 00043 * 00044 * Revision 1.1.1.1 2003/05/09 14:41:45 haraldkipp 00045 * Initial using 3.2.1 00046 * 00047 * Revision 1.10 2003/05/06 18:23:15 harald 00048 * Still not done 00049 * 00050 * Revision 1.9 2003/02/04 18:14:57 harald 00051 * Version 3 released 00052 * 00053 * Revision 1.8 2002/06/26 17:29:36 harald 00054 * First pre-release with 2.4 stack 00055 * 00056 */ 00057 00058 #include <cfg/tcp.h> 00059 00060 #include <netinet/tcputil.h> 00061 #include <sys/timer.h> 00062 #include <stdio.h> 00063 00068 00069 /* Limit retransmission timeout to 200ms as lower and 20secs as upper boundary */ 00070 #ifndef TCP_RTTO_MIN 00071 #define TCP_RTTO_MIN 200 00072 #endif 00073 #ifndef TCP_RTTO_MAX 00074 #define TCP_RTTO_MAX 20000 00075 #endif 00076 00083 int IsInLimits(u_long x, u_long low, u_long high) 00084 { 00085 if (low <= high) { 00086 if (low <= x && x <= high) 00087 return 1; 00088 } else if (low >= x && x >= high) 00089 return 1; 00090 00091 return 0; 00092 } 00093 00094 #define min(a,b) ((a>b)?b:a) 00095 #define max(a,b) ((a>b)?a:b) 00096 00097 /* 00098 * Calculate round trip time. 00099 */ 00100 void NutTcpCalcRtt(TCPSOCKET * sock) 00101 { 00102 u_short delta; 00103 00104 if (sock->so_retran_time == 0) 00105 return; 00106 00107 delta = (u_short) NutGetMillis() - sock->so_retran_time; 00108 00109 /* According to RFC793 (or STD007), page 41, we use 0.8 for ALPHA and 2.0 for BETA. */ 00110 sock->so_rtto = min (TCP_RTTO_MAX, max(TCP_RTTO_MIN, (delta * 4 + sock->so_rtto * 8) / 10)); 00111 //@@@printf ("[%04X] new retran timeout: %u, delta: %u\n", (u_short) sock, sock->so_rtto, delta); 00112 } 00113