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This cleans up the timer code in TCP and also makes it so we do not

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take the INFO lock *unless* we are really going to delete the TCB.

Differential Revision:	D7136
This commit is contained in:
Randall Stewart 2016-08-16 12:40:56 +00:00
parent 0295d98c14
commit b07fef500b
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=304218
2 changed files with 93 additions and 98 deletions
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188
sys/netinet/tcp_timer.c
View File

@ -294,11 +294,6 @@ tcp_timer_delack(void *xtp)
CURVNET_RESTORE();
return;
}
KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0,
("%s: tp %p tcpcb can't be stopped here", __func__, tp));
KASSERT((tp->t_timers->tt_flags & TT_DELACK) != 0,
("%s: tp %p delack callout should be running", __func__, tp));
tp->t_flags |= TF_ACKNOW;
TCPSTAT_INC(tcps_delack);
(void) tp->t_fb->tfb_tcp_output(tp);
@ -306,6 +301,39 @@ tcp_timer_delack(void *xtp)
CURVNET_RESTORE();
}
int
tcp_inpinfo_lock_add(struct inpcb *inp)
{
in_pcbref(inp);
INP_WUNLOCK(inp);
INP_INFO_RLOCK(&V_tcbinfo);
INP_WLOCK(inp);
if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
return(1);
}
return(0);
}
void
tcp_inpinfo_lock_del(struct inpcb *inp, struct tcpcb *tp)
{
INP_INFO_RUNLOCK(&V_tcbinfo);
if (inp && (tp == NULL)) {
/*
* If tcp_close/drop() gets called and tp
* returns NULL, then the function dropped
* the inp lock, we hold a reference keeping
* this around, so we must re-aquire the
* INP_WLOCK() in order to proceed with
* our dropping the inp reference.
*/
INP_WLOCK(inp);
}
if (inp && in_pcbrele_wlocked(inp) == 0)
INP_WUNLOCK(inp);
}
void
tcp_timer_2msl(void *xtp)
{
@ -317,7 +345,6 @@ tcp_timer_2msl(void *xtp)
ostate = tp->t_state;
#endif
INP_INFO_RLOCK(&V_tcbinfo);
inp = tp->t_inpcb;
KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
INP_WLOCK(inp);
@ -325,21 +352,17 @@ tcp_timer_2msl(void *xtp)
if (callout_pending(&tp->t_timers->tt_2msl) ||
!callout_active(&tp->t_timers->tt_2msl)) {
INP_WUNLOCK(tp->t_inpcb);
INP_INFO_RUNLOCK(&V_tcbinfo);
CURVNET_RESTORE();
return;
}
callout_deactivate(&tp->t_timers->tt_2msl);
if ((inp->inp_flags & INP_DROPPED) != 0) {
INP_WUNLOCK(inp);
INP_INFO_RUNLOCK(&V_tcbinfo);
CURVNET_RESTORE();
return;
}
KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0,
("%s: tp %p tcpcb can't be stopped here", __func__, tp));
KASSERT((tp->t_timers->tt_flags & TT_2MSL) != 0,
("%s: tp %p 2msl callout should be running", __func__, tp));
/*
* 2 MSL timeout in shutdown went off. If we're closed but
* still waiting for peer to close and connection has been idle
@ -355,7 +378,6 @@ tcp_timer_2msl(void *xtp)
*/
if ((inp->inp_flags & INP_TIMEWAIT) != 0) {
INP_WUNLOCK(inp);
INP_INFO_RUNLOCK(&V_tcbinfo);
CURVNET_RESTORE();
return;
}
@ -363,15 +385,26 @@ tcp_timer_2msl(void *xtp)
tp->t_inpcb && tp->t_inpcb->inp_socket &&
(tp->t_inpcb->inp_socket->so_rcv.sb_state & SBS_CANTRCVMORE)) {
TCPSTAT_INC(tcps_finwait2_drops);
if (tcp_inpinfo_lock_add(inp)) {
tcp_inpinfo_lock_del(inp, tp);
goto out;
}
tp = tcp_close(tp);
tcp_inpinfo_lock_del(inp, tp);
goto out;
} else {
if (ticks - tp->t_rcvtime <= TP_MAXIDLE(tp)) {
if (!callout_reset(&tp->t_timers->tt_2msl,
TP_KEEPINTVL(tp), tcp_timer_2msl, tp)) {
tp->t_timers->tt_flags &= ~TT_2MSL_RST;
callout_reset(&tp->t_timers->tt_2msl,
TP_KEEPINTVL(tp), tcp_timer_2msl, tp);
} else {
if (tcp_inpinfo_lock_add(inp)) {
tcp_inpinfo_lock_del(inp, tp);
goto out;
}
} else
tp = tcp_close(tp);
tp = tcp_close(tp);
tcp_inpinfo_lock_del(inp, tp);
goto out;
}
}
#ifdef TCPDEBUG
@ -383,7 +416,7 @@ tcp_timer_2msl(void *xtp)
if (tp != NULL)
INP_WUNLOCK(inp);
INP_INFO_RUNLOCK(&V_tcbinfo);
out:
CURVNET_RESTORE();
}
@ -399,28 +432,23 @@ tcp_timer_keep(void *xtp)
ostate = tp->t_state;
#endif
INP_INFO_RLOCK(&V_tcbinfo);
inp = tp->t_inpcb;
KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
INP_WLOCK(inp);
if (callout_pending(&tp->t_timers->tt_keep) ||
!callout_active(&tp->t_timers->tt_keep)) {
INP_WUNLOCK(inp);
INP_INFO_RUNLOCK(&V_tcbinfo);
CURVNET_RESTORE();
return;
}
callout_deactivate(&tp->t_timers->tt_keep);
if ((inp->inp_flags & INP_DROPPED) != 0) {
INP_WUNLOCK(inp);
INP_INFO_RUNLOCK(&V_tcbinfo);
CURVNET_RESTORE();
return;
}
KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0,
("%s: tp %p tcpcb can't be stopped here", __func__, tp));
KASSERT((tp->t_timers->tt_flags & TT_KEEP) != 0,
("%s: tp %p keep callout should be running", __func__, tp));
/*
* Keep-alive timer went off; send something
* or drop connection if idle for too long.
@ -452,14 +480,11 @@ tcp_timer_keep(void *xtp)
tp->rcv_nxt, tp->snd_una - 1, 0);
free(t_template, M_TEMP);
}
if (!callout_reset(&tp->t_timers->tt_keep, TP_KEEPINTVL(tp),
tcp_timer_keep, tp)) {
tp->t_timers->tt_flags &= ~TT_KEEP_RST;
}
} else if (!callout_reset(&tp->t_timers->tt_keep, TP_KEEPIDLE(tp),
tcp_timer_keep, tp)) {
tp->t_timers->tt_flags &= ~TT_KEEP_RST;
}
callout_reset(&tp->t_timers->tt_keep, TP_KEEPINTVL(tp),
tcp_timer_keep, tp);
} else
callout_reset(&tp->t_timers->tt_keep, TP_KEEPIDLE(tp),
tcp_timer_keep, tp);
#ifdef TCPDEBUG
if (inp->inp_socket->so_options & SO_DEBUG)
@ -468,12 +493,16 @@ tcp_timer_keep(void *xtp)
#endif
TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO);
INP_WUNLOCK(inp);
INP_INFO_RUNLOCK(&V_tcbinfo);
CURVNET_RESTORE();
return;
dropit:
TCPSTAT_INC(tcps_keepdrops);
if (tcp_inpinfo_lock_add(inp)) {
tcp_inpinfo_lock_del(inp, tp);
goto out;
}
tp = tcp_drop(tp, ETIMEDOUT);
#ifdef TCPDEBUG
@ -482,9 +511,8 @@ tcp_timer_keep(void *xtp)
PRU_SLOWTIMO);
#endif
TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO);
if (tp != NULL)
INP_WUNLOCK(tp->t_inpcb);
INP_INFO_RUNLOCK(&V_tcbinfo);
tcp_inpinfo_lock_del(inp, tp);
out:
CURVNET_RESTORE();
}
@ -499,28 +527,23 @@ tcp_timer_persist(void *xtp)
ostate = tp->t_state;
#endif
INP_INFO_RLOCK(&V_tcbinfo);
inp = tp->t_inpcb;
KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
INP_WLOCK(inp);
if (callout_pending(&tp->t_timers->tt_persist) ||
!callout_active(&tp->t_timers->tt_persist)) {
INP_WUNLOCK(inp);
INP_INFO_RUNLOCK(&V_tcbinfo);
CURVNET_RESTORE();
return;
}
callout_deactivate(&tp->t_timers->tt_persist);
if ((inp->inp_flags & INP_DROPPED) != 0) {
INP_WUNLOCK(inp);
INP_INFO_RUNLOCK(&V_tcbinfo);
CURVNET_RESTORE();
return;
}
KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0,
("%s: tp %p tcpcb can't be stopped here", __func__, tp));
KASSERT((tp->t_timers->tt_flags & TT_PERSIST) != 0,
("%s: tp %p persist callout should be running", __func__, tp));
/*
* Persistence timer into zero window.
* Force a byte to be output, if possible.
@ -537,7 +560,12 @@ tcp_timer_persist(void *xtp)
(ticks - tp->t_rcvtime >= tcp_maxpersistidle ||
ticks - tp->t_rcvtime >= TCP_REXMTVAL(tp) * tcp_totbackoff)) {
TCPSTAT_INC(tcps_persistdrop);
if (tcp_inpinfo_lock_add(inp)) {
tcp_inpinfo_lock_del(inp, tp);
goto out;
}
tp = tcp_drop(tp, ETIMEDOUT);
tcp_inpinfo_lock_del(inp, tp);
goto out;
}
/*
@ -547,7 +575,12 @@ tcp_timer_persist(void *xtp)
if (tp->t_state > TCPS_CLOSE_WAIT &&
(ticks - tp->t_rcvtime) >= TCPTV_PERSMAX) {
TCPSTAT_INC(tcps_persistdrop);
if (tcp_inpinfo_lock_add(inp)) {
tcp_inpinfo_lock_del(inp, tp);
goto out;
}
tp = tcp_drop(tp, ETIMEDOUT);
tcp_inpinfo_lock_del(inp, tp);
goto out;
}
tcp_setpersist(tp);
@ -555,15 +588,13 @@ tcp_timer_persist(void *xtp)
(void) tp->t_fb->tfb_tcp_output(tp);
tp->t_flags &= ~TF_FORCEDATA;
out:
#ifdef TCPDEBUG
if (tp != NULL && tp->t_inpcb->inp_socket->so_options & SO_DEBUG)
tcp_trace(TA_USER, ostate, tp, NULL, NULL, PRU_SLOWTIMO);
#endif
TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO);
if (tp != NULL)
INP_WUNLOCK(inp);
INP_INFO_RUNLOCK(&V_tcbinfo);
INP_WUNLOCK(inp);
out:
CURVNET_RESTORE();
}
@ -573,36 +604,29 @@ tcp_timer_rexmt(void * xtp)
struct tcpcb *tp = xtp;
CURVNET_SET(tp->t_vnet);
int rexmt;
int headlocked;
struct inpcb *inp;
#ifdef TCPDEBUG
int ostate;
ostate = tp->t_state;
#endif
INP_INFO_RLOCK(&V_tcbinfo);
inp = tp->t_inpcb;
KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp));
INP_WLOCK(inp);
if (callout_pending(&tp->t_timers->tt_rexmt) ||
!callout_active(&tp->t_timers->tt_rexmt)) {
INP_WUNLOCK(inp);
INP_INFO_RUNLOCK(&V_tcbinfo);
CURVNET_RESTORE();
return;
}
callout_deactivate(&tp->t_timers->tt_rexmt);
if ((inp->inp_flags & INP_DROPPED) != 0) {
INP_WUNLOCK(inp);
INP_INFO_RUNLOCK(&V_tcbinfo);
CURVNET_RESTORE();
return;
}
KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0,
("%s: tp %p tcpcb can't be stopped here", __func__, tp));
KASSERT((tp->t_timers->tt_flags & TT_REXMT) != 0,
("%s: tp %p rexmt callout should be running", __func__, tp));
tcp_free_sackholes(tp);
if (tp->t_fb->tfb_tcp_rexmit_tmr) {
/* The stack has a timer action too. */
@ -616,14 +640,15 @@ tcp_timer_rexmt(void * xtp)
if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) {
tp->t_rxtshift = TCP_MAXRXTSHIFT;
TCPSTAT_INC(tcps_timeoutdrop);
if (tcp_inpinfo_lock_add(inp)) {
tcp_inpinfo_lock_del(inp, tp);
goto out;
}
tp = tcp_drop(tp, tp->t_softerror ?
tp->t_softerror : ETIMEDOUT);
headlocked = 1;
tcp_inpinfo_lock_del(inp, tp);
goto out;
}
INP_INFO_RUNLOCK(&V_tcbinfo);
headlocked = 0;
if (tp->t_state == TCPS_SYN_SENT) {
/*
* If the SYN was retransmitted, indicate CWND to be
@ -811,17 +836,14 @@ tcp_timer_rexmt(void * xtp)
(void) tp->t_fb->tfb_tcp_output(tp);
out:
#ifdef TCPDEBUG
if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
PRU_SLOWTIMO);
#endif
TCP_PROBE2(debug__user, tp, PRU_SLOWTIMO);
if (tp != NULL)
INP_WUNLOCK(inp);
if (headlocked)
INP_INFO_RUNLOCK(&V_tcbinfo);
INP_WUNLOCK(inp);
out:
CURVNET_RESTORE();
}
@ -832,7 +854,6 @@ tcp_timer_activate(struct tcpcb *tp, uint32_t timer_type, u_int delta)
timeout_t *f_callout;
struct inpcb *inp = tp->t_inpcb;
int cpu = inp_to_cpuid(inp);
uint32_t f_reset;
#ifdef TCP_OFFLOAD
if (tp->t_flags & TF_TOE)
@ -846,27 +867,22 @@ tcp_timer_activate(struct tcpcb *tp, uint32_t timer_type, u_int delta)
case TT_DELACK:
t_callout = &tp->t_timers->tt_delack;
f_callout = tcp_timer_delack;
f_reset = TT_DELACK_RST;
break;
case TT_REXMT:
t_callout = &tp->t_timers->tt_rexmt;
f_callout = tcp_timer_rexmt;
f_reset = TT_REXMT_RST;
break;
case TT_PERSIST:
t_callout = &tp->t_timers->tt_persist;
f_callout = tcp_timer_persist;
f_reset = TT_PERSIST_RST;
break;
case TT_KEEP:
t_callout = &tp->t_timers->tt_keep;
f_callout = tcp_timer_keep;
f_reset = TT_KEEP_RST;
break;
case TT_2MSL:
t_callout = &tp->t_timers->tt_2msl;
f_callout = tcp_timer_2msl;
f_reset = TT_2MSL_RST;
break;
default:
if (tp->t_fb->tfb_tcp_timer_activate) {
@ -876,24 +892,9 @@ tcp_timer_activate(struct tcpcb *tp, uint32_t timer_type, u_int delta)
panic("tp %p bad timer_type %#x", tp, timer_type);
}
if (delta == 0) {
if ((tp->t_timers->tt_flags & timer_type) &&
(callout_stop(t_callout) > 0) &&
(tp->t_timers->tt_flags & f_reset)) {
tp->t_timers->tt_flags &= ~(timer_type | f_reset);
}
callout_stop(t_callout);
} else {
if ((tp->t_timers->tt_flags & timer_type) == 0) {
tp->t_timers->tt_flags |= (timer_type | f_reset);
callout_reset_on(t_callout, delta, f_callout, tp, cpu);
} else {
/* Reset already running callout on the same CPU. */
if (!callout_reset(t_callout, delta, f_callout, tp)) {
/*
* Callout not cancelled, consider it as not
* properly restarted. */
tp->t_timers->tt_flags &= ~f_reset;
}
}
callout_reset_on(t_callout, delta, f_callout, tp, cpu);
}
}
@ -931,30 +932,23 @@ void
tcp_timer_stop(struct tcpcb *tp, uint32_t timer_type)
{
struct callout *t_callout;
uint32_t f_reset;
tp->t_timers->tt_flags |= TT_STOPPED;
switch (timer_type) {
case TT_DELACK:
t_callout = &tp->t_timers->tt_delack;
f_reset = TT_DELACK_RST;
break;
case TT_REXMT:
t_callout = &tp->t_timers->tt_rexmt;
f_reset = TT_REXMT_RST;
break;
case TT_PERSIST:
t_callout = &tp->t_timers->tt_persist;
f_reset = TT_PERSIST_RST;
break;
case TT_KEEP:
t_callout = &tp->t_timers->tt_keep;
f_reset = TT_KEEP_RST;
break;
case TT_2MSL:
t_callout = &tp->t_timers->tt_2msl;
f_reset = TT_2MSL_RST;
break;
default:
if (tp->t_fb->tfb_tcp_timer_stop) {
@ -968,15 +962,13 @@ tcp_timer_stop(struct tcpcb *tp, uint32_t timer_type)
panic("tp %p bad timer_type %#x", tp, timer_type);
}
if (tp->t_timers->tt_flags & timer_type) {
if (callout_async_drain(t_callout, tcp_timer_discard) == 0) {
/*
* Can't stop the callout, defer tcpcb actual deletion
* to the last one. We do this using the async drain
* function and incrementing the count in
*/
tp->t_timers->tt_draincnt++;
}
if (callout_async_drain(t_callout, tcp_timer_discard) == 0) {
/*
* Can't stop the callout, defer tcpcb actual deletion
* to the last one. We do this using the async drain
* function and incrementing the count in
*/
tp->t_timers->tt_draincnt++;
}
}

3
sys/netinet/tcp_timer.h
View File

@ -191,6 +191,9 @@ extern int tcp_syn_backoff[];
extern int tcp_finwait2_timeout;
extern int tcp_fast_finwait2_recycle;
int tcp_inpinfo_lock_add(struct inpcb *inp);
void tcp_inpinfo_lock_del(struct inpcb *inp, struct tcpcb *tp);
void tcp_timer_init(void);
void tcp_timer_2msl(void *xtp);
void tcp_timer_discard(void *);