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Diffstat (limited to 'lib/libtle_l4p/tcp_timer.h')
| -rw-r--r-- | lib/libtle_l4p/tcp_timer.h | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/lib/libtle_l4p/tcp_timer.h b/lib/libtle_l4p/tcp_timer.h new file mode 100644 index 0000000..8faefb3 --- /dev/null +++ b/lib/libtle_l4p/tcp_timer.h @@ -0,0 +1,126 @@ +/* + * Copyright (c) 2016 Intel Corporation. + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at: + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#ifndef _TCP_TIMER_H_ +#define _TCP_TIMER_H_ + +#include <tle_timer.h> + +#ifdef __cplusplus +extern "C" { +#endif + +/* + * internal defines. + * all RTO values are in ms. + */ +#define TCP_RTO_MAX 60000U /* RFC 6298 (2.5) */ +#define TCP_RTO_MIN 1000U /* RFC 6298 (2.4) */ +#define TCP_RTO_2MSL (2 * TCP_RTO_MAX) +#define TCP_RTO_DEFAULT TCP_RTO_MIN /* RFC 6298 (2.1)*/ +#define TCP_RTO_GRANULARITY 100U + + +static inline void +timer_stop(struct tle_tcp_stream *s) +{ + struct tle_timer_wheel *tw; + + if (s->timer.handle != NULL) { + tw = CTX_TCP_TMWHL(s->s.ctx); + tle_timer_stop(tw, s->timer.handle); + s->timer.handle = NULL; + } +} + +static inline void +timer_start(struct tle_tcp_stream *s) +{ + struct tle_timer_wheel *tw; + + if (s->timer.handle == NULL) { + tw = CTX_TCP_TMWHL(s->s.ctx); + s->timer.handle = tle_timer_start(tw, s, s->tcb.snd.rto); + s->tcb.snd.nb_retx = 0; + } +} + +static inline void +timer_restart(struct tle_tcp_stream *s) +{ + struct tle_timer_wheel *tw; + + tw = CTX_TCP_TMWHL(s->s.ctx); + s->timer.handle = tle_timer_start(tw, s, s->tcb.snd.rto); +} + + +/* + * reset number of retransmissions and restart RTO timer. + */ +static inline void +timer_reset(struct tle_tcp_stream *s) +{ + timer_stop(s); + timer_start(s); +} + +static inline uint32_t +rto_roundup(uint32_t rto) +{ + rto = RTE_MAX(rto, TCP_RTO_MIN); + rto = RTE_MIN(rto, TCP_RTO_MAX); + return rto; +} + +/* + * RFC6298: Computing TCP's Retransmission Timer + * RTTVAR <- (1 - beta) * RTTVAR + beta * |SRTT - R'| + * SRTT <- (1 - alpha) * SRTT + alpha * R' + * RTO <- SRTT + max (G, K*RTTVAR) + * the following computation is based on Jacobson'88 paper referenced + * in the RFC6298 +*/ +static inline void +rto_estimate(struct tcb *tcb, int32_t rtt) +{ + uint32_t rto; + + if (!rtt) + rtt = 1; + if (tcb->rcv.srtt) { + rtt -= (tcb->rcv.srtt >> 3); /* alpha = 1/8 */ + tcb->rcv.srtt += rtt; + + if (rtt < 0) + rtt = -rtt; + rtt -= (tcb->rcv.rttvar >> 2); /* beta = 1/4 */ + tcb->rcv.rttvar += rtt; + + } else { + tcb->rcv.srtt = rtt << 3; + tcb->rcv.rttvar = rtt << 1; + } + + rto = (tcb->rcv.srtt >> 3) + + RTE_MAX(TCP_RTO_GRANULARITY, tcb->rcv.rttvar); + tcb->snd.rto = rto_roundup(rto); +} + +#ifdef __cplusplus +} +#endif + +#endif /* _TCP_TIMER_H_ */ |