ee7d245b6f50eb8264e2eba3554980e4deb3fa06
* Copyright (c) 1991 The Regents of the University of California.
* %sccs.include.redist.c%
* @(#)tp_subr.c 7.11 (Berkeley) %G%
/***********************************************************
Copyright IBM Corporation 1987
Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation, and that the name of IBM not be
used in advertising or publicity pertaining to distribution of the
software without specific, written prior permission.
IBM DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
IBM BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
******************************************************************/
* ARGO Project, Computer Sciences Dept., University of Wisconsin - Madison
* $Header: tp_subr.c,v 5.3 88/11/18 17:28:43 nhall Exp $
* $Source: /usr/argo/sys/netiso/RCS/tp_subr.c,v $
* The main work of data transfer is done here.
* These routines are called from tp.trans.
* They include the routines that check the validity of acks and Xacks,
* (tp_goodack() and tp_goodXack() )
* take packets from socket buffers and send them (tp_send()),
* drop the data from the socket buffers (tp_sbdrop()),
* and put incoming packet data into socket buffers (tp_stash()).
#define SMOOTH(newtype, alpha, old, new) \
(newtype) (((new - old)>>alpha) + (old))
(type) (((int)(val)<0)?-(val):(val))
* tp.trans, when an XAK arrives
* FUNCTION and ARGUMENTS:
* Determines if the sequence number (seq) from the XAK
* acks anything new. If so, drop the appropriate tpdu
* from the XPD send queue.
* Returns 1 if it did this, 0 if the ack caused no action.
seq
, tpcb
->tp_Xuna
, tpcb
->tp_Xsndnxt
, tpcb
->tp_sndhiwat
,
if ( seq
== tpcb
->tp_Xuna
) {
tpcb
->tp_Xuna
= tpcb
->tp_Xsndnxt
;
/* DROP 1 packet from the Xsnd socket buf - just so happens
* that only one packet can be there at any time
* so drop the whole thing. If you allow > 1 packet
* the socket buffer, then you'll have to keep
* track of how many characters went w/ each XPD tpdu, so this
dump_mbuf(tpcb
->tp_Xsnd
.sb_mb
,
"tp_goodXack Xsnd before sbdrop");
"goodXack: dropping cc ",
(int)(tpcb
->tp_Xsnd
.sb_cc
),
sbdrop( &tpcb
->tp_Xsnd
, (int)(tpcb
->tp_Xsnd
.sb_cc
));
* FUNCTION and ARGUMENTS:
* smoothed average round trip time (base_rtt)
* roundtrip time variance (base_rtv) - actually deviation, not variance
* given the new value (diff)
tp_rtt_rtv( base_rtt
, base_rtv
, newmeas
)
struct timeval
*base_rtt
, *base_rtv
, *newmeas
;
/* update rt variance (really just the deviation):
* rtv.smooth_ave = SMOOTH( | oldrtt.smooth_avg - rtt.this_instance | )
SMOOTH( long, TP_RTV_ALPHA
, base_rtv
->tv_sec
,
ABS( long, base_rtt
->tv_sec
- newmeas
->tv_sec
));
SMOOTH( long, TP_RTV_ALPHA
, base_rtv
->tv_usec
,
ABS(long, base_rtt
->tv_usec
- newmeas
->tv_usec
));
/* update smoothed average rtt */
SMOOTH( long, TP_RTT_ALPHA
, base_rtt
->tv_sec
, newmeas
->tv_sec
);
SMOOTH( long, TP_RTT_ALPHA
, base_rtt
->tv_usec
, newmeas
->tv_usec
);
* tp.trans when an AK arrives
* FUNCTION and ARGUMENTS:
* Given (cdt), the credit from the AK tpdu, and
* (seq), the sequence number from the AK tpdu,
* tp_goodack() determines if the AK acknowledges something in the send
* window, and if so, drops the appropriate packets from the retransmission
* list, computes the round trip time, and updates the retransmission timer
* based on the new smoothed round trip time.
* EITHER it actually acked something heretofore unacknowledged
* OR no news but the credit should be processed.
* If something heretofore unacked was acked with this sequence number,
* the appropriate tpdus are dropped from the retransmission control list,
* by calling tp_sbdrop().
* No need to see the tpdu itself.
tp_goodack(tpcb
, cdt
, seq
, subseq
)
register struct tp_pcb
*tpcb
;
register SeqNum seq
, subseq
;
int old_fcredit
= tpcb
->tp_fcredit
;
int bang
= 0; /* bang --> ack for something heretofore unacked */
printf("goodack seq 0x%x cdt 0x%x snduna 0x%x sndhiwat 0x%x\n",
seq
, cdt
, tpcb
->tp_snduna
, tpcb
->tp_sndhiwat
);
seq
,cdt
, tpcb
->tp_snduna
,tpcb
->tp_sndhiwat
,subseq
);
tpmeas(tpcb
->tp_lref
, TPtime_ack_rcvd
, (struct timeval
*)0, seq
, 0, 0);
if ( subseq
!= 0 && (subseq
<= tpcb
->tp_r_subseq
) ) {
tptraceTPCB(TPPTmisc
, "goodack discard : subseq tp_r_subseq",
subseq
, tpcb
->tp_r_subseq
, 0, 0);
tpcb
->tp_r_subseq
= subseq
;
if ( IN_SWINDOW(tpcb
, seq
,
tpcb
->tp_snduna
, SEQ(tpcb
, tpcb
->tp_sndhiwat
+1)) ) {
dump_mbuf(tpcb
->tp_sock
->so_snd
.sb_mb
,
"tp_goodack snd before sbdrop");
/* increase congestion window but don't let it get too big */
register int maxcdt
= tpcb
->tp_xtd_format
?0xffff:0xf;
/* Compute smoothed round trip time.
* Only measure rtt for tp_snduna if tp_snduna was among
* the last TP_RTT_NUM seq numbers sent, and if the data
* were not retransmitted.
if (SEQ_GEQ(tpcb
, tpcb
->tp_snduna
,
SEQ(tpcb
, tpcb
->tp_sndhiwat
- TP_RTT_NUM
))
&& SEQ_GT(tpcb
, seq
, SEQ_ADD(tpcb
, tpcb
->tp_retrans_hiwat
, 1))) {
struct timeval
*t
= &tpcb
->tp_rttemit
[tpcb
->tp_snduna
& TP_RTT_NUM
];
tp_rtt_rtv( &(tpcb
->tp_rtt
), &(tpcb
->tp_rtv
), &x
);
{ /* update the global rtt, rtv stats */
(int) tpcb
->tp_flags
& (TPF_PEER_ON_SAMENET
| TPF_NLQOS_PDN
);
tp_rtt_rtv( &(tp_stat
.ts_rtt
[i
]), &(tp_stat
.ts_rtv
[i
]), &x
);
tptraceTPCB(TPPTmisc
, "Global rtt, rtv: i", i
, 0, 0, 0);
"Smoothed rtt: tp_snduna, (time.sec, time.usec), peer_acktime",
tpcb
->tp_snduna
, time
.tv_sec
, time
.tv_usec
,
"(secs): emittime diff(x) rtt, rtv",
"(usecs): emittime diff(x) rtt rtv",
/* Update data retransmission timer based on the smoothed
* round trip time, peer ack time, and the pseudo-arbitrary
* new ticks: avg rtt + 2*dev
* rtt, rtv are in microsecs, and ticks are 500 ms
* so 1 tick = 500*1000 us = 500000 us
* so ticks = (rtt + 2 rtv)/500000
* with ticks no les than peer ack time and no less than 4
int rtt
= tpcb
->tp_rtt
.tv_usec
+
tpcb
->tp_rtt
.tv_sec
*1000000;
int rtv
= tpcb
->tp_rtv
.tv_usec
+
tpcb
->tp_rtv
.tv_sec
*1000000;
tptraceTPCB(TPPTmisc
, "oldticks ,rtv, rtt, newticks",
(rtt
/500000 + (2 * rtv
)/500000));
tpcb
->tp_dt_ticks
= (rtt
+ (2 * rtv
))/500000;
tpcb
->tp_dt_ticks
= MAX( tpcb
->tp_dt_ticks
,
tpcb
->tp_dt_ticks
= MAX( tpcb
->tp_dt_ticks
, 4);
tpcb
->tp_retrans
= tpcb
->tp_Nretrans
; /* CE_BIT */
if( cdt
!= 0 && old_fcredit
== 0 ) {
if( cdt
== 0 && old_fcredit
!= 0 ) {
printf("goodack returning 0x%x, bang 0x%x cdt 0x%x old_fcredit 0x%x\n",
(bang
|| (old_fcredit
< cdt
) ), bang
, cdt
, old_fcredit
);
return (bang
|| (old_fcredit
< cdt
)) ;
* FUNCTION and ARGUMENTS:
* drops everything up TO but not INCLUDING seq # (seq)
* from the retransmission queue.
register struct tp_pcb
*tpcb
;
struct sockbuf
*sb
= &tpcb
->tp_sock
->so_snd
;
register int i
= ((int)seq
)-((int)tpcb
->tp_snduna
);
if (i
< 0) i
+= tpcb
->tp_seqhalf
;
printf("tp_sbdroping %d up through seq 0x%x\n", i
, seq
);
if (SEQ_LT(tpcb
, tpcb
->tp_sndhiwat
, seq
))
* tp.trans on user send request, arrival of AK and arrival of XAK
* FUNCTION and ARGUMENTS:
* Emits tpdus starting at sequence number (lowseq).
* Emits until a) runs out of data, or b) runs into an XPD mark, or
* c) it hits seq number (highseq)
* If you want XPD to buffer > 1 du per socket buffer, you can
* modifiy this to issue XPD tpdus also, but then it'll have
* to take some argument(s) to distinguish between the type of DU to
* When something is sent for the first time, its time-of-send
* is stashed (the last RTT_NUM of them are stashed). When the
* ack arrives, the smoothed round-trip time is figured using this value.
* the highest seq # sent successfully.
register struct tp_pcb
*tpcb
;
register struct mbuf
*m
; /* the one we're inspecting now */
struct mbuf
*mb
;/* beginning of this tpdu */
struct mbuf
*nextrecord
; /* NOT next tpdu but next sb record */
struct sockbuf
*sb
= &tpcb
->tp_sock
->so_snd
;
unsigned int eotsdu_reached
=0;
struct timeval send_start_time
;
GET_CUR_TIME(&send_start_time
);
lowsave
= lowseq
= SEQ(tpcb
, tpcb
->tp_sndhiwat
+ 1);
ASSERT( tpcb
->tp_cong_win
> 0 && tpcb
->tp_cong_win
< 0xffff);
if( tpcb
->tp_rx_strat
& TPRX_USE_CW
) {
/*first hiseq is temp vbl*/
highseq
= MIN(tpcb
->tp_fcredit
, tpcb
->tp_cong_win
);
highseq
= tpcb
->tp_fcredit
;
highseq
= SEQ(tpcb
, tpcb
->tp_snduna
+ highseq
);
"tp_send enter tpcb 0x%x l %d -> h %d\ndump of sb_mb:\n",
dump_mbuf(sb
->sb_mb
, "sb_mb:");
tptraceTPCB( TPPTmisc
, "tp_send lowsave sndhiwat snduna",
lowsave
, tpcb
->tp_sndhiwat
, tpcb
->tp_snduna
, 0);
tptraceTPCB( TPPTmisc
, "tp_send low high fcredit congwin",
lowseq
, highseq
, tpcb
->tp_fcredit
, tpcb
->tp_cong_win
);
if ( SEQ_GT(tpcb
, lowseq
, highseq
) )
return ; /* don't send, don't change hiwat, don't set timers */
ASSERT( SEQ_LEQ(tpcb
, lowseq
, highseq
) );
if (tpcb
->tp_Xsnd
.sb_mb
) {
"tp_send XPD mark low high tpcb.Xuna",
lowseq
, highseq
, tpcb
->tp_Xsnd
.sb_mb
, 0);
/* stop sending here because there are unacked XPD present
IncStat(ts_xpd_intheway
);
tptraceTPCB( TPPTmisc
, "tp_send 2 low high fcredit congwin",
lowseq
, highseq
, tpcb
->tp_fcredit
, tpcb
->tp_cong_win
);
if (m
= tpcb
->tp_sndhiwat_m
)
while ((SEQ_LT(tpcb
, lowseq
, highseq
)) && mb
) {
* In all cases, m points to mbuf containing first octet to be
* sent in the tpdu AFTER the one we're going to send now,
* The chain we're working on now begins at mb and has length <len>.
eotsdu_reached
= (mb
->m_flags
& M_EOR
) != 0;
"tp_send mcopy low high eotsdu_reached len",
lowseq
, highseq
, eotsdu_reached
, len
);
/* make a copy - mb goes into the retransmission list
* while m gets emitted. m_copy won't copy a zero-length mbuf.
m
= m_copy(mb
, 0, M_COPYALL
);
SEQ_INC(tpcb
,lowseq
); /* it was decremented at the beginning */
"tp_send emitting DT lowseq eotsdu_reached len",
lowseq
, eotsdu_reached
, len
, 0);
if (mb
->m_nextpkt
== 0 && tpcb
->tp_oktonagle
) {
SEQ_INC(tpcb
, tpcb
->tp_sndnum
);
/* when headers are precomputed, may need to fill
if (tpcb
->tp_sock
->so_error
=
tp_emit(DT_TPDU_type
, tpcb
, lowseq
, eotsdu_reached
, m
)) {
tpcb
->tp_sndhiwat_m
= mb
;
/* set the transmit-time for computation of round-trip times */
(caddr_t
)&( tpcb
->tp_rttemit
[ lowseq
& TP_RTT_NUM
] ),
struct timeval send_end_time
;
register struct timeval
*t
;
npkts
= SEQ_SUB(tpcb
, npkts
, lowsave
);
GET_TIME_SINCE(&send_start_time
, &send_end_time
);
t
= &(tpcb
->tp_p_meas
->tps_sendtime
[npkts
]);
SMOOTH( long, TP_RTT_ALPHA
, t
->tv_sec
, send_end_time
.tv_sec
);
SMOOTH( long, TP_RTT_ALPHA
, t
->tv_usec
, send_end_time
.tv_usec
);
if ( SEQ_LT(tpcb
, lowseq
, highseq
) ) {
IncPStat(tpcb
, tps_win_lim_by_data
[npkts
] );
IncPStat(tpcb
, tps_win_lim_by_cdt
[npkts
] );
/* not true with congestion-window being used */
TPsbsend
, &send_end_time
, lowsave
, tpcb
->tp_Nwindow
, npkts
);
tpcb
->tp_sndhiwat
= lowseq
;
if ( SEQ_LEQ(tpcb
, lowsave
, tpcb
->tp_sndhiwat
) &&
(tpcb
->tp_class
!= TP_CLASS_0
) )
tp_etimeout(tpcb
->tp_refp
, TM_data_retrans
, lowsave
,
(u_int
)tpcb
->tp_Nretrans
, (int)tpcb
->tp_dt_ticks
);
"tp_send at end: sndhiwat lowseq eotsdu_reached error",
tpcb
->tp_sndhiwat
, lowseq
, eotsdu_reached
, tpcb
->tp_sock
->so_error
);
tp_packetize(tpcb
, m
, eotsdu
)
register struct tp_pcb
*tpcb
;
register struct sockbuf
*sb
= &tpcb
->tp_sock
->so_snd
;
int maxsize
= tpcb
->tp_l_tpdusize
- tp_headersize(DT_TPDU_type
, tpcb
)
- (tpcb
->tp_use_checksum
?4:0) ;
int totlen
= m
->m_pkthdr
.len
;
* Pre-packetize the data in the sockbuf
* according to negotiated mtu. Do it here
* where we can safely wait for mbufs.
* This presumes knowledge of sockbuf conventions.
* TODO: allocate space for header and fill it in (once!).
"SEND BF: maxsize totlen eotsdu",
maxsize
, totlen
, eotsdu
, 0);
if (tpcb
->tp_oktonagle
) {
if ((n
= sb
->sb_mb
) == 0)
SEQ_INC(tpcb
, tpcb
->tp_sndnum
);
if (totlen
+ n
->m_pkthdr
.len
< maxsize
) {
/* There is an unsent packet with space, combine data */
n
->m_pkthdr
.len
+= totlen
;
if ((m
= m_split(n
, maxsize
, M_WAIT
)) == 0)
SEQ_INC(tpcb
, tpcb
->tp_sndnum
);
n
->m_flags
|= M_EOR
; /* XXX belongs at end */
SEQ_DEC(tpcb
, tpcb
->tp_sndnum
);
* tp.trans on arrival of a DT tpdu
* FUNCTION, ARGUMENTS, and RETURN VALUE:
* a) something new arrived and it's got eotsdu_reached bit on,
* b) this arrival was caused other out-of-sequence things to be
* c) this arrival is the highest seq # for which we last gave credit
* (sender just sent a whole window)
* In other words, returns 1 if tp should send an ack immediately, 0 if
* the ack can wait a while.
* Note: this implementation no longer renegs on credit, (except
* when debugging option D_RENEG is on, for the purpose of testing
* ack subsequencing), so we don't need to check for incoming tpdus
* being in a reneged portion of the window.
register struct tp_pcb
*tpcb
;
register struct tp_event
*e
;
register int ack_reason
= tpcb
->tp_ack_strat
& ACK_STRAT_EACH
;
/* 0--> delay acks until full window */
#define E e->ATTR(DT_TPDU)
#define E e->ev_union.EV_DT_TPDU
register struct mbuf
*n
= E
.e_data
;
dump_mbuf(tpcb
->tp_sock
->so_rcv
.sb_mb
,
"stash: so_rcv before appending");
"stash: e_data before appending");
PStat(tpcb
, Nb_from_ll
) += E
.e_datalen
;
tpmeas(tpcb
->tp_lref
, TPtime_from_ll
, &e
->e_time
,
E
.e_seq
, (u_int
)PStat(tpcb
, Nb_from_ll
), (u_int
)E
.e_datalen
);
if( E
.e_seq
== tpcb
->tp_rcvnxt
) {
printf("stash EQ: seq 0x%x datalen 0x%x eot 0x%x\n",
E
.e_seq
, E
.e_datalen
, E
.e_eot
);
tptraceTPCB(TPPTmisc
, "stash EQ: seq len eot",
E
.e_seq
, E
.e_datalen
, E
.e_eot
, 0);
sbappend(&tpcb
->tp_sock
->so_rcv
, E
.e_data
);
SEQ_INC( tpcb
, tpcb
->tp_rcvnxt
);
* move chains from the reassembly queue to the socket buffer
register struct mbuf
**mp
;
mp
= tpcb
->tp_rsyq
+ (tpcb
->tp_rcvnxt
% tpcb
->tp_maxlcredit
);
mplim
= tpcb
->tp_rsyq
+ tpcb
->tp_maxlcredit
;
while (tpcb
->tp_rsycnt
&& *mp
) {
sbappend(&tpcb
->tp_sock
->so_rcv
, *mp
);
SEQ_INC(tpcb
, tpcb
->tp_rcvnxt
);
ack_reason
|= ACK_REORDER
;
dump_mbuf(tpcb
->tp_sock
->so_rcv
.sb_mb
,
"stash: so_rcv after appending");
register struct mbuf
**mp
;
tptraceTPCB(TPPTmisc
, "stash Reseq: seq rcvnxt lcdt",
E
.e_seq
, tpcb
->tp_rcvnxt
, tpcb
->tp_lcredit
, 0);
if (tpcb
->tp_rsyq
== 0 ||
(tpcb
->tp_sbmax
!= tpcb
->tp_sock
->so_rcv
.sb_hiwat
)))
uwe
= SEQ(tpcb
, tpcb
->tp_rcvnxt
+ tpcb
->tp_maxlcredit
);
if (tpcb
->tp_rsyq
== 0 ||
!IN_RWINDOW(tpcb
, E
.e_seq
, tpcb
->tp_rcvnxt
, uwe
)) {
} else if (*(mp
= tpcb
->tp_rsyq
+ (E
.e_seq
% tpcb
->tp_maxlcredit
))) {
printf("tp_stash - drop & ack\n");
/* retransmission - drop it and force an ack */
IncPStat(tpcb
, tps_n_ack_cuz_dup
);
* an ack should be sent when at least one of the
* a) the TPDU that just arrived represents the
* full window last advertised, or
* b) when seq X arrives [ where
* X = last_sent_uwe - 1/2 last_lcredit_sent
* (the packet representing 1/2 the last advertised window) ]
* and lcredit at the time of X arrival > last_lcredit_sent/2
* In other words, if the last ack sent advertised cdt=8 and uwe = 8
* then when seq 4 arrives I'd like to send a new ack
* iff the credit at the time of 4's arrival is > 4.
* The other end thinks it has cdt of 4 so if local cdt
* is still 4 there's no point in sending an ack, but if
* my credit has increased because the receiver has taken
* some data out of the buffer (soreceive doesn't notify
* me until the SYSTEM CALL finishes), I'd like to tell
if ( E
.e_seq
== tpcb
->tp_sent_uwe
)
ack_reason
|= ACK_STRAT_FULLWIN
;
"end of stash, eot, ack_reason, sent_uwe ",
E
.e_eot
, ack_reason
, tpcb
->tp_sent_uwe
, 0);
if ( ack_reason
== ACK_DONT
) {
IncStat( ts_ackreason
[ACK_DONT
] );
if(ack_reason
& ACK_STRAT_EACH
) {
IncPStat(tpcb
, tps_n_ack_cuz_strat
);
} else if(ack_reason
& ACK_STRAT_FULLWIN
) {
IncPStat(tpcb
, tps_n_ack_cuz_fullwin
);
} else if(ack_reason
& ACK_REORDER
) {
IncPStat(tpcb
, tps_n_ack_cuz_reorder
);
tpmeas(tpcb
->tp_lref
, TPtime_ack_sent
, 0,
SEQ_ADD(tpcb
, E
.e_seq
, 1), 0, 0);
/* keep track of all reasons that apply */
for( i
=1; i
<_ACK_NUM_REASONS_
;i
++) {
if( ack_reason
& (1<<i
) )
IncStat( ts_ackreason
[i
] );
* tp_rsyflush - drop all the packets on the reassembly queue.
* Do this when closing the socket, or when somebody has changed
* the space avaible in the receive socket (XXX).
register struct tp_pcb
*tpcb
;
register struct mbuf
*m
, **mp
;
for (mp
== tpcb
->tp_rsyq
+ tpcb
->tp_maxlcredit
;
free((caddr_t
)tpcb
->tp_rsyq
, M_PCB
);
register struct tp_pcb
*tpcb
;
register struct socket
*so
= tpcb
->tp_sock
;
int maxcredit
= tpcb
->tp_xtd_format
? 0xffff : 0xf;
tpcb
->tp_sbmax
= so
->so_rcv
.sb_hiwat
;
tpcb
->tp_maxlcredit
= maxcredit
= min(maxcredit
,
(so
->so_rcv
.sb_hiwat
+ tpcb
->tp_l_tpdusize
)/ tpcb
->tp_l_tpdusize
);
maxcredit
*= sizeof(struct mbuf
*);
if (rsyq
= (caddr_t
)malloc(maxcredit
, M_PCB
, M_NOWAIT
))
tpcb
->tp_rsyq
= (struct mbuf
**)rsyq
;
register struct mbuf
*n
, *m
;
register int len
= 0, mbcnt
= 0, pktlen
;
struct sockbuf
*sb
= &tpcb
->tp_sock
->so_snd
;
for (n
= sb
->sb_mb
; n
; n
= n
->m_nextpkt
) {
if ((n
->m_flags
& M_PKTHDR
) == 0)
panic("tpsbcheck nohdr");
pktlen
= len
+ n
->m_pkthdr
.len
;
for (m
= n
; m
; m
= m
->m_next
) {
mbcnt
+= m
->m_ext
.ext_size
;
printf("test %d; len %d != pktlen %d on mbuf 0x%x\n",
panic("tpsbcheck short");
if (len
!= sb
->sb_cc
|| mbcnt
!= sb
->sb_mbcnt
) {
printf("test %d: cc %d != %d || mbcnt %d != %d\n", i
, len
, sb
->sb_cc
,