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Diffstat (limited to 'external/unbound/util/rtt.c')
| -rw-r--r-- | external/unbound/util/rtt.c | 121 |
1 files changed, 0 insertions, 121 deletions
diff --git a/external/unbound/util/rtt.c b/external/unbound/util/rtt.c deleted file mode 100644 index 5d86f1337..000000000 --- a/external/unbound/util/rtt.c +++ /dev/null @@ -1,121 +0,0 @@ -/* - * util/rtt.c - UDP round trip time estimator for resend timeouts. - * - * Copyright (c) 2007, NLnet Labs. All rights reserved. - * - * This software is open source. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * - * Redistributions of source code must retain the above copyright notice, - * this list of conditions and the following disclaimer. - * - * Redistributions in binary form must reproduce the above copyright notice, - * this list of conditions and the following disclaimer in the documentation - * and/or other materials provided with the distribution. - * - * Neither the name of the NLNET LABS nor the names of its contributors may - * be used to endorse or promote products derived from this software without - * specific prior written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS - * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT - * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR - * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT - * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, - * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED - * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR - * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF - * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING - * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS - * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - */ - -/** - * \file - * - * This file contains a data type and functions to help estimate good - * round trip times for UDP resend timeout values. - */ -#include "config.h" -#include "util/rtt.h" - -/* overwritten by config: infra_cache_min_rtt: */ -int RTT_MIN_TIMEOUT = 50; -/** calculate RTO from rtt information */ -static int -calc_rto(const struct rtt_info* rtt) -{ - /* From Stevens, Unix Network Programming, Vol1, 3rd ed., p.598 */ - int rto = rtt->srtt + 4*rtt->rttvar; - if(rto < RTT_MIN_TIMEOUT) - rto = RTT_MIN_TIMEOUT; - if(rto > RTT_MAX_TIMEOUT) - rto = RTT_MAX_TIMEOUT; - return rto; -} - -void -rtt_init(struct rtt_info* rtt) -{ - rtt->srtt = 0; - rtt->rttvar = 94; - rtt->rto = calc_rto(rtt); - /* default value from the book is 0 + 4*0.75 = 3 seconds */ - /* first RTO is 0 + 4*0.094 = 0.376 seconds */ -} - -int -rtt_timeout(const struct rtt_info* rtt) -{ - return rtt->rto; -} - -int -rtt_unclamped(const struct rtt_info* rtt) -{ - if(calc_rto(rtt) != rtt->rto) { - /* timeout fallback has happened */ - return rtt->rto; - } - /* return unclamped value */ - return rtt->srtt + 4*rtt->rttvar; -} - -void -rtt_update(struct rtt_info* rtt, int ms) -{ - int delta = ms - rtt->srtt; - rtt->srtt += delta / 8; /* g = 1/8 */ - if(delta < 0) - delta = -delta; /* |delta| */ - rtt->rttvar += (delta - rtt->rttvar) / 4; /* h = 1/4 */ - rtt->rto = calc_rto(rtt); -} - -void -rtt_lost(struct rtt_info* rtt, int orig) -{ - /* exponential backoff */ - - /* if a query succeeded and put down the rto meanwhile, ignore this */ - if(rtt->rto < orig) - return; - - /* the original rto is doubled, not the current one to make sure - * that the values in the cache are not increased by lots of - * queries simultaneously as they time out at the same time */ - orig *= 2; - if(rtt->rto <= orig) { - rtt->rto = orig; - if(rtt->rto > RTT_MAX_TIMEOUT) - rtt->rto = RTT_MAX_TIMEOUT; - } -} - -int rtt_notimeout(const struct rtt_info* rtt) -{ - return calc_rto(rtt); -} |