Date: Mon, 27 Jun 2011 14:35:48 GMT From: Catalin Nicutar <cnicutar@FreeBSD.org> To: Perforce Change Reviews <perforce@freebsd.org> Subject: PERFORCE change 195421 for review Message-ID: <201106271435.p5REZmwX057382@skunkworks.freebsd.org>
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http://p4web.freebsd.org/@@195421?ac=10 Change 195421 by cnicutar@cnicutar_cronos on 2011/06/27 14:35:32 When using UTO don't reset the connection if TCP_MAXRXTSHIFT retransmits are sent and the timeout has not been exceeded. If UTO is exceeded, drop the connection regardless of the number of retransmits performed. Add a field to tcpcb to record the starting time of retransmissions (and, implicitly, UTO). Affected files ... .. //depot/projects/soc2011/cnicutar_tcputo_8/src/sys/netinet/tcp_timer.c#3 edit .. //depot/projects/soc2011/cnicutar_tcputo_8/src/sys/netinet/tcp_var.h#5 edit Differences ... ==== //depot/projects/soc2011/cnicutar_tcputo_8/src/sys/netinet/tcp_timer.c#3 (text+ko) ==== @@ -66,6 +66,9 @@ #include <netinet/tcp_debug.h> #endif +/* XXX-CN this will have to move */ +#define ticks_to_secs(t) ((t) / hz) + int tcp_keepinit; SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINIT, keepinit, CTLTYPE_INT|CTLFLAG_RW, &tcp_keepinit, 0, sysctl_msec_to_ticks, "I", "time to establish connection"); @@ -117,6 +120,7 @@ /* max idle time in persist */ int tcp_maxidle; + /* * Tcp protocol timeout routine called every 500 ms. * Updates timestamps used for TCP @@ -452,6 +456,7 @@ int rexmt; int headlocked; struct inpcb *inp; + int uto_left = 0; #ifdef TCPDEBUG int ostate; @@ -483,16 +488,49 @@ } callout_deactivate(&tp->t_timers->tt_rexmt); tcp_free_sackholes(tp); + + if (tp->t_rxtshift == 0) + tp->t_suto = 0; + + if ((tp->t_flags & TF_SND_UTO) || ((tp->t_flags & TF_RCV_UTO) && + tp->rcv_uto)) { + /* Using UTO for this connection. */ + uto_left = max(tp->snd_uto, tp->rcv_uto); + if (tp->t_suto) { + uto_left -= ticks_to_secs(ticks - tp->t_suto); + } + + /* + * The user may choose a value that's less than TCP_MAXRXTSHIFT + * retransmits. + */ + if (tp->t_rxtshift > TCP_MAXRXTSHIFT || uto_left <= 0) { + /* Before or after the retransmits, UTO was exceeded. */ + TCPSTAT_INC(tcps_timeoutdrop); + tp = tcp_drop(tp, ETIMEDOUT); + goto out; + } + } + /* * Retransmission timer went off. Message has not * been acked within retransmit interval. Back off * to a longer retransmit interval and retransmit one segment. */ if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) { - tp->t_rxtshift = TCP_MAXRXTSHIFT; - TCPSTAT_INC(tcps_timeoutdrop); - tp = tcp_drop(tp, tp->t_softerror ? - tp->t_softerror : ETIMEDOUT); + if (uto_left > 0) { + /* + * Reset the timer for UTO; t_rxtshift will hint + * that it's not a normal retransmit. + */ + callout_reset(&tp->t_timers->tt_rexmt, hz * uto_left, + tcp_timer_rexmt, tp); + } else { + tp->t_rxtshift = TCP_MAXRXTSHIFT; + TCPSTAT_INC(tcps_timeoutdrop); + tp = tcp_drop(tp, tp->t_softerror ? + tp->t_softerror : ETIMEDOUT); + } goto out; } INP_INFO_WUNLOCK(&V_tcbinfo); @@ -515,6 +553,7 @@ else tp->t_flags &= ~TF_WASFRECOVERY; tp->t_badrxtwin = ticks + (tp->t_srtt >> (TCP_RTT_SHIFT + 1)); + tp->t_suto = ticks; /* Keep track of UTO start. */ } TCPSTAT_INC(tcps_rexmttimeo); if (tp->t_state == TCPS_SYN_SENT) @@ -523,6 +562,9 @@ rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift]; TCPT_RANGESET(tp->t_rxtcur, rexmt, tp->t_rttmin, TCPTV_REXMTMAX); + if (uto_left) { + tp->t_rxtcur = min(tp->t_rxtcur, hz * uto_left); + } /* * Disable rfc1323 if we haven't got any response to * our third SYN to work-around some broken terminal servers ==== //depot/projects/soc2011/cnicutar_tcputo_8/src/sys/netinet/tcp_var.h#5 (text+ko) ==== @@ -200,13 +200,14 @@ void *t_pspare2[6]; /* 2 CC / 4 TBD */ - uint64_t _pad[8]; /* 5 UTO, 3 TBD (1-2 CC/RTT?) */ + uint64_t _pad[7]; /* 4 UTO, 3 TBD (1-2 CC/RTT?) */ uint64_t t_sndrexmitpack;/* retransmit packets sent */ uint64_t t_rcvoopack; /* out-of-order packets received */ uint64_t snd_uto; /* sent timeout */ uint64_t rcv_uto; /* received suggestion from peer */ + uint64_t t_suto; /* uto starting time */ }; /*
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