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Unify the "send high" and "recover" variables as specified in the

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lastest rev of the spec.  Use an explicit flag for Fast Recovery. [1]

Fix bug with exiting Fast Recovery on a retransmit timeout
diagnosed by Lu Guohan. [2]

Reviewed by:		Thomas Henderson <thomas.r.henderson@boeing.com>
Reported and tested by:	Lu Guohan <lguohan00@mails.tsinghua.edu.cn> [2]
Approved by:		Thomas Henderson <thomas.r.henderson@boeing.com>,
			Sally Floyd <floyd@acm.org> [1]
This commit is contained in:
Jeffrey Hsu 2003-07-15 21:49:53 +00:00
parent ff40920e9e
commit 9d11646de7
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=117650
5 changed files with 83 additions and 63 deletions
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43
sys/netinet/tcp_input.c
View File

@ -992,8 +992,7 @@ tcp_input(m, off0)
tp->snd_cwnd >= tp->snd_wnd &&
((!tcp_do_newreno &&
tp->t_dupacks < tcprexmtthresh) ||
(tcp_do_newreno &&
!SEQ_LT(tp->snd_una, tp->snd_recover)))) {
(tcp_do_newreno && !IN_FASTRECOVERY(tp)))) {
KASSERT(headlocked, ("headlocked"));
INP_INFO_WUNLOCK(&tcbinfo);
/*
@ -1009,7 +1008,9 @@ tcp_input(m, off0)
tp->snd_cwnd = tp->snd_cwnd_prev;
tp->snd_ssthresh =
tp->snd_ssthresh_prev;
tp->snd_high = tp->snd_high_prev;
tp->snd_recover = tp->snd_recover_prev;
if (tp->t_flags & TF_WASFRECOVERY)
ENTER_FASTRECOVERY(tp);
tp->snd_nxt = tp->snd_max;
tp->t_badrxtwin = 0;
}
@ -1036,10 +1037,10 @@ tcp_input(m, off0)
tcpstat.tcps_rcvackpack++;
tcpstat.tcps_rcvackbyte += acked;
sbdrop(&so->so_snd, acked);
if (SEQ_GT(tp->snd_una, tp->snd_high) &&
SEQ_LEQ(th->th_ack, tp->snd_high))
tp->snd_high = th->th_ack - 1;
tp->snd_una = tp->snd_recover = th->th_ack;
if (SEQ_GT(tp->snd_una, tp->snd_recover) &&
SEQ_LEQ(th->th_ack, tp->snd_recover))
tp->snd_recover = th->th_ack - 1;
tp->snd_una = th->th_ack;
/*
* pull snd_wl2 up to prevent seq wrap relative
* to th_ack.
@ -1739,8 +1740,7 @@ tcp_input(m, off0)
tp->t_dupacks = 0;
else if (++tp->t_dupacks > tcprexmtthresh ||
(tcp_do_newreno &&
SEQ_LT(tp->snd_una,
tp->snd_recover))) {
IN_FASTRECOVERY(tp))) {
tp->snd_cwnd += tp->t_maxseg;
(void) tcp_output(tp);
goto drop;
@ -1748,7 +1748,8 @@ tcp_input(m, off0)
tcp_seq onxt = tp->snd_nxt;
u_int win;
if (tcp_do_newreno &&
SEQ_LEQ(th->th_ack, tp->snd_high)) {
SEQ_LEQ(th->th_ack,
tp->snd_recover)) {
tp->t_dupacks = 0;
break;
}
@ -1757,6 +1758,7 @@ tcp_input(m, off0)
if (win < 2)
win = 2;
tp->snd_ssthresh = win * tp->t_maxseg;
ENTER_FASTRECOVERY(tp);
tp->snd_recover = tp->snd_max;
callout_stop(tp->tt_rexmt);
tp->t_rtttime = 0;
@ -1809,7 +1811,7 @@ tcp_input(m, off0)
* for the other side's cached packets, retract it.
*/
if (tcp_do_newreno) {
if (SEQ_LT(tp->snd_una, tp->snd_recover)) {
if (IN_FASTRECOVERY(tp)) {
if (SEQ_LT(th->th_ack, tp->snd_recover)) {
tcp_newreno_partial_ack(tp, th);
} else {
@ -1879,7 +1881,9 @@ tcp_input(m, off0)
++tcpstat.tcps_sndrexmitbad;
tp->snd_cwnd = tp->snd_cwnd_prev;
tp->snd_ssthresh = tp->snd_ssthresh_prev;
tp->snd_high = tp->snd_high_prev;
tp->snd_recover = tp->snd_recover_prev;
if (tp->t_flags & TF_WASFRECOVERY)
ENTER_FASTRECOVERY(tp);
tp->snd_nxt = tp->snd_max;
tp->t_badrxtwin = 0; /* XXX probably not required */
}
@ -1933,7 +1937,7 @@ tcp_input(m, off0)
* Otherwise open linearly: maxseg per window
* (maxseg^2 / cwnd per packet).
*/
if (!tcp_do_newreno || SEQ_GEQ(tp->snd_una, tp->snd_recover)) {
if (!tcp_do_newreno || !IN_FASTRECOVERY(tp)) {
register u_int cw = tp->snd_cwnd;
register u_int incr = tp->t_maxseg;
if (cw > tp->snd_ssthresh)
@ -1951,12 +1955,13 @@ tcp_input(m, off0)
}
sowwakeup(so);
/* detect una wraparound */
if (SEQ_GEQ(tp->snd_una, tp->snd_recover) &&
SEQ_LT(th->th_ack, tp->snd_recover))
tp->snd_recover = th->th_ack;
if (SEQ_GT(tp->snd_una, tp->snd_high) &&
SEQ_LEQ(th->th_ack, tp->snd_high))
tp->snd_high = th->th_ack - 1;
if (tcp_do_newreno && !IN_FASTRECOVERY(tp) &&
SEQ_GT(tp->snd_una, tp->snd_recover) &&
SEQ_LEQ(th->th_ack, tp->snd_recover))
tp->snd_recover = th->th_ack - 1;
if (tcp_do_newreno && IN_FASTRECOVERY(tp) &&
SEQ_GEQ(th->th_ack, tp->snd_recover))
EXIT_FASTRECOVERY(tp);
tp->snd_una = th->th_ack;
if (SEQ_LT(tp->snd_nxt, tp->snd_una))
tp->snd_nxt = tp->snd_una;

43
sys/netinet/tcp_reass.c
View File

@ -992,8 +992,7 @@ tcp_input(m, off0)
tp->snd_cwnd >= tp->snd_wnd &&
((!tcp_do_newreno &&
tp->t_dupacks < tcprexmtthresh) ||
(tcp_do_newreno &&
!SEQ_LT(tp->snd_una, tp->snd_recover)))) {
(tcp_do_newreno && !IN_FASTRECOVERY(tp)))) {
KASSERT(headlocked, ("headlocked"));
INP_INFO_WUNLOCK(&tcbinfo);
/*
@ -1009,7 +1008,9 @@ tcp_input(m, off0)
tp->snd_cwnd = tp->snd_cwnd_prev;
tp->snd_ssthresh =
tp->snd_ssthresh_prev;
tp->snd_high = tp->snd_high_prev;
tp->snd_recover = tp->snd_recover_prev;
if (tp->t_flags & TF_WASFRECOVERY)
ENTER_FASTRECOVERY(tp);
tp->snd_nxt = tp->snd_max;
tp->t_badrxtwin = 0;
}
@ -1036,10 +1037,10 @@ tcp_input(m, off0)
tcpstat.tcps_rcvackpack++;
tcpstat.tcps_rcvackbyte += acked;
sbdrop(&so->so_snd, acked);
if (SEQ_GT(tp->snd_una, tp->snd_high) &&
SEQ_LEQ(th->th_ack, tp->snd_high))
tp->snd_high = th->th_ack - 1;
tp->snd_una = tp->snd_recover = th->th_ack;
if (SEQ_GT(tp->snd_una, tp->snd_recover) &&
SEQ_LEQ(th->th_ack, tp->snd_recover))
tp->snd_recover = th->th_ack - 1;
tp->snd_una = th->th_ack;
/*
* pull snd_wl2 up to prevent seq wrap relative
* to th_ack.
@ -1739,8 +1740,7 @@ tcp_input(m, off0)
tp->t_dupacks = 0;
else if (++tp->t_dupacks > tcprexmtthresh ||
(tcp_do_newreno &&
SEQ_LT(tp->snd_una,
tp->snd_recover))) {
IN_FASTRECOVERY(tp))) {
tp->snd_cwnd += tp->t_maxseg;
(void) tcp_output(tp);
goto drop;
@ -1748,7 +1748,8 @@ tcp_input(m, off0)
tcp_seq onxt = tp->snd_nxt;
u_int win;
if (tcp_do_newreno &&
SEQ_LEQ(th->th_ack, tp->snd_high)) {
SEQ_LEQ(th->th_ack,
tp->snd_recover)) {
tp->t_dupacks = 0;
break;
}
@ -1757,6 +1758,7 @@ tcp_input(m, off0)
if (win < 2)
win = 2;
tp->snd_ssthresh = win * tp->t_maxseg;
ENTER_FASTRECOVERY(tp);
tp->snd_recover = tp->snd_max;
callout_stop(tp->tt_rexmt);
tp->t_rtttime = 0;
@ -1809,7 +1811,7 @@ tcp_input(m, off0)
* for the other side's cached packets, retract it.
*/
if (tcp_do_newreno) {
if (SEQ_LT(tp->snd_una, tp->snd_recover)) {
if (IN_FASTRECOVERY(tp)) {
if (SEQ_LT(th->th_ack, tp->snd_recover)) {
tcp_newreno_partial_ack(tp, th);
} else {
@ -1879,7 +1881,9 @@ tcp_input(m, off0)
++tcpstat.tcps_sndrexmitbad;
tp->snd_cwnd = tp->snd_cwnd_prev;
tp->snd_ssthresh = tp->snd_ssthresh_prev;
tp->snd_high = tp->snd_high_prev;
tp->snd_recover = tp->snd_recover_prev;
if (tp->t_flags & TF_WASFRECOVERY)
ENTER_FASTRECOVERY(tp);
tp->snd_nxt = tp->snd_max;
tp->t_badrxtwin = 0; /* XXX probably not required */
}
@ -1933,7 +1937,7 @@ tcp_input(m, off0)
* Otherwise open linearly: maxseg per window
* (maxseg^2 / cwnd per packet).
*/
if (!tcp_do_newreno || SEQ_GEQ(tp->snd_una, tp->snd_recover)) {
if (!tcp_do_newreno || !IN_FASTRECOVERY(tp)) {
register u_int cw = tp->snd_cwnd;
register u_int incr = tp->t_maxseg;
if (cw > tp->snd_ssthresh)
@ -1951,12 +1955,13 @@ tcp_input(m, off0)
}
sowwakeup(so);
/* detect una wraparound */
if (SEQ_GEQ(tp->snd_una, tp->snd_recover) &&
SEQ_LT(th->th_ack, tp->snd_recover))
tp->snd_recover = th->th_ack;
if (SEQ_GT(tp->snd_una, tp->snd_high) &&
SEQ_LEQ(th->th_ack, tp->snd_high))
tp->snd_high = th->th_ack - 1;
if (tcp_do_newreno && !IN_FASTRECOVERY(tp) &&
SEQ_GT(tp->snd_una, tp->snd_recover) &&
SEQ_LEQ(th->th_ack, tp->snd_recover))
tp->snd_recover = th->th_ack - 1;
if (tcp_do_newreno && IN_FASTRECOVERY(tp) &&
SEQ_GEQ(th->th_ack, tp->snd_recover))
EXIT_FASTRECOVERY(tp);
tp->snd_una = th->th_ack;
if (SEQ_LT(tp->snd_nxt, tp->snd_una))
tp->snd_nxt = tp->snd_una;

2
sys/netinet/tcp_seq.h
View File

@ -73,7 +73,7 @@
#define tcp_sendseqinit(tp) \
(tp)->snd_una = (tp)->snd_nxt = (tp)->snd_max = (tp)->snd_up = \
(tp)->snd_recover = (tp)->snd_high = (tp)->iss
(tp)->snd_recover = (tp)->iss
#define TCP_PAWS_IDLE (24 * 24 * 60 * 60 * hz)
/* timestamp wrap-around time */

9
sys/netinet/tcp_timer.c
View File

@ -528,7 +528,11 @@ tcp_timer_rexmt(xtp)
*/
tp->snd_cwnd_prev = tp->snd_cwnd;
tp->snd_ssthresh_prev = tp->snd_ssthresh;
tp->snd_high_prev = tp->snd_high;
tp->snd_recover_prev = tp->snd_recover;
if (IN_FASTRECOVERY(tp))
tp->t_flags |= TF_WASFRECOVERY;
else
tp->t_flags &= ~TF_WASFRECOVERY;
tp->t_badrxtwin = ticks + (tp->t_srtt >> (TCP_RTT_SHIFT + 1));
}
tcpstat.tcps_rexmttimeo++;
@ -566,7 +570,7 @@ tcp_timer_rexmt(xtp)
tp->t_srtt = 0;
}
tp->snd_nxt = tp->snd_una;
tp->snd_high = tp->snd_max;
tp->snd_recover = tp->snd_max;
/*
* Force a segment to be sent.
*/
@ -607,6 +611,7 @@ tcp_timer_rexmt(xtp)
tp->snd_ssthresh = win * tp->t_maxseg;
tp->t_dupacks = 0;
}
EXIT_FASTRECOVERY(tp);
(void) tcp_output(tp);
out:

49
sys/netinet/tcp_var.h
View File

@ -83,26 +83,28 @@ struct tcpcb {
struct inpcb *t_inpcb; /* back pointer to internet pcb */
int t_state; /* state of this connection */
u_int t_flags;
#define TF_ACKNOW 0x00001 /* ack peer immediately */
#define TF_DELACK 0x00002 /* ack, but try to delay it */
#define TF_NODELAY 0x00004 /* don't delay packets to coalesce */
#define TF_NOOPT 0x00008 /* don't use tcp options */
#define TF_SENTFIN 0x00010 /* have sent FIN */
#define TF_REQ_SCALE 0x00020 /* have/will request window scaling */
#define TF_RCVD_SCALE 0x00040 /* other side has requested scaling */
#define TF_REQ_TSTMP 0x00080 /* have/will request timestamps */
#define TF_RCVD_TSTMP 0x00100 /* a timestamp was received in SYN */
#define TF_SACK_PERMIT 0x00200 /* other side said I could SACK */
#define TF_NEEDSYN 0x00400 /* send SYN (implicit state) */
#define TF_NEEDFIN 0x00800 /* send FIN (implicit state) */
#define TF_NOPUSH 0x01000 /* don't push */
#define TF_REQ_CC 0x02000 /* have/will request CC */
#define TF_RCVD_CC 0x04000 /* a CC was received in SYN */
#define TF_SENDCCNEW 0x08000 /* send CCnew instead of CC in SYN */
#define TF_MORETOCOME 0x10000 /* More data to be appended to sock */
#define TF_LQ_OVERFLOW 0x20000 /* listen queue overflow */
#define TF_LASTIDLE 0x40000 /* connection was previously idle */
#define TF_RXWIN0SENT 0x80000 /* sent a receiver win 0 in response */
#define TF_ACKNOW 0x000001 /* ack peer immediately */
#define TF_DELACK 0x000002 /* ack, but try to delay it */
#define TF_NODELAY 0x000004 /* don't delay packets to coalesce */
#define TF_NOOPT 0x000008 /* don't use tcp options */
#define TF_SENTFIN 0x000010 /* have sent FIN */
#define TF_REQ_SCALE 0x000020 /* have/will request window scaling */
#define TF_RCVD_SCALE 0x000040 /* other side has requested scaling */
#define TF_REQ_TSTMP 0x000080 /* have/will request timestamps */
#define TF_RCVD_TSTMP 0x000100 /* a timestamp was received in SYN */
#define TF_SACK_PERMIT 0x000200 /* other side said I could SACK */
#define TF_NEEDSYN 0x000400 /* send SYN (implicit state) */
#define TF_NEEDFIN 0x000800 /* send FIN (implicit state) */
#define TF_NOPUSH 0x001000 /* don't push */
#define TF_REQ_CC 0x002000 /* have/will request CC */
#define TF_RCVD_CC 0x004000 /* a CC was received in SYN */
#define TF_SENDCCNEW 0x008000 /* send CCnew instead of CC in SYN */
#define TF_MORETOCOME 0x010000 /* More data to be appended to sock */
#define TF_LQ_OVERFLOW 0x020000 /* listen queue overflow */
#define TF_LASTIDLE 0x040000 /* connection was previously idle */
#define TF_RXWIN0SENT 0x080000 /* sent a receiver win 0 in response */
#define TF_FASTRECOVERY 0x100000 /* in NewReno Fast Recovery */
#define TF_WASFRECOVERY 0x200000 /* was in NewReno Fast Recovery */
int t_force; /* 1 if forcing out a byte */
tcp_seq snd_una; /* send unacknowledged */
@ -131,7 +133,6 @@ struct tcpcb {
*/
u_long snd_bandwidth; /* calculated bandwidth or 0 */
tcp_seq snd_recover; /* for use in NewReno Fast Recovery */
tcp_seq snd_high; /* for use in NewReno Fast Recovery */
u_int t_maxopd; /* mss plus options */
@ -175,11 +176,15 @@ struct tcpcb {
/* experimental */
u_long snd_cwnd_prev; /* cwnd prior to retransmit */
u_long snd_ssthresh_prev; /* ssthresh prior to retransmit */
tcp_seq snd_high_prev; /* snd_high prior to retransmit */
tcp_seq snd_recover_prev; /* snd_recover prior to retransmit */
u_long t_badrxtwin; /* window for retransmit recovery */
u_char snd_limited; /* segments limited transmitted */
};
#define IN_FASTRECOVERY(tp) (tp->t_flags & TF_FASTRECOVERY)
#define ENTER_FASTRECOVERY(tp) tp->t_flags |= TF_FASTRECOVERY
#define EXIT_FASTRECOVERY(tp) tp->t_flags &= ~TF_FASTRECOVERY
/*
* Structure to hold TCP options that are only used during segment
* processing (in tcp_input), but not held in the tcpcb.