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Differential D49414 Diff 152467 sys/netinet/tcp_input.c

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sys/netinet/tcp_input.c

Show First 20 Lines • Show All 1,629 Lines • ▼ Show 20 Lines#endif
* fall back to non RFC1323 RTT calculation. Normalize * fall back to non RFC1323 RTT calculation. Normalize
* timestamp if syncookies were used when this connection * timestamp if syncookies were used when this connection
* was established. * was established.
*/ */
if ((to.to_flags & TOF_TS) && (to.to_tsecr != 0)) { if ((to.to_flags & TOF_TS) && (to.to_tsecr != 0)) {
to.to_tsecr -= tp->ts_offset; to.to_tsecr -= tp->ts_offset;
if (TSTMP_GT(to.to_tsecr, tcp_ts_getticks())) { if (TSTMP_GT(to.to_tsecr, tcp_ts_getticks())) {
to.to_tsecr = 0; to.to_tsecr = 0;
} else if (tp->t_rxtshift == 1 &&
tp->t_flags & TF_PREVVALID &&
tp->t_badrxtwin != 0 &&
TSTMP_LT(to.to_tsecr, tp->t_badrxtwin)) {
cc_cong_signal(tp, th, CC_RTO_ERR);
} }
} }
/* /*
* Process options only when we get SYN/ACK back. The SYN case * Process options only when we get SYN/ACK back. The SYN case
* for incoming connections is handled in tcp_syncache. * for incoming connections is handled in tcp_syncache.
* According to RFC1323 the window field in a SYN (i.e., a <SYN> * According to RFC1323 the window field in a SYN (i.e., a <SYN>
* or <SYN,ACK>) segment itself is never scaled. * or <SYN,ACK>) segment itself is never scaled.
* XXX this is traditional behavior, may need to be cleaned up. * XXX this is traditional behavior, may need to be cleaned up.
▲ Show 20 Lines • Show All 136 Lines • ▼ Show 20 Lines if (tlen == 0) {
(to.to_flags & TOF_SACK) == 0 && (to.to_flags & TOF_SACK) == 0 &&
TAILQ_EMPTY(&tp->snd_holes)) { TAILQ_EMPTY(&tp->snd_holes)) {
/* /*
* This is a pure ack for outstanding data. * This is a pure ack for outstanding data.
*/ */
TCPSTAT_INC(tcps_predack); TCPSTAT_INC(tcps_predack);
/* /*
* "bad retransmit" recovery without timestamps. * "bad retransmit" recovery.
*/ */
if ((to.to_flags & TOF_TS) == 0 && if (tp->t_rxtshift == 1 &&
tp->t_rxtshift == 1 &&
tp->t_flags & TF_PREVVALID && tp->t_flags & TF_PREVVALID &&
tp->t_badrxtwin != 0 && tp->t_badrxtwin != 0 &&
TSTMP_LT(ticks, tp->t_badrxtwin)) { (((to.to_flags & TOF_TS) != 0 &&
to.to_tsecr != 0 &&
TSTMP_LT(to.to_tsecr, tp->t_badrxtwin)) ||
((to.to_flags & TOF_TS) == 0 &&
TSTMP_LT(ticks, tp->t_badrxtwin))))
cc_cong_signal(tp, th, CC_RTO_ERR); cc_cong_signal(tp, th, CC_RTO_ERR);
}
/* /*
* Recalculate the transmit timer / rtt. * Recalculate the transmit timer / rtt.
* *
* Some boxes send broken timestamp replies * Some boxes send broken timestamp replies
rscheffUnsubmitted
Done
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Any specific reason to write the or statement as two separate if clauses?

I believe in other parts we do it ((true & x & y & z) | (false & a & b &c )) - as multiline checks;

I don't like them both get executed "always", so at the very least, an "else" just before the 2nd if would be good.

The logic looks ok to me.

rscheff: Any specific reason to write the or statement as two separate if clauses? I believe in other…
glebiusUnsubmitted
Done
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I agree with Richard, better one complex if clause. The two clauses are mutually exclusive as one wants TOF_TS and other !TOF_TS, so cc_cong_signal() can be executed only once. My first reading was that it is intentionally written this way cause we may want two calls into cc_cong_singal(), so it was a misleading reading.

Oh, the upper level embracing if can also be merged into one big clause:

if ((tp->t_rxtshift == 1 &&
    tp->t_flags & TF_PREVVALID &&
    tp->t_badrxtwin != 0) &&
    (((to.to_flags & TOF_TS) != 0 &&
    (to.to_tsecr != 0) &&
    TSTMP_LT(to.to_tsecr, tp->t_badrxtwin)) ||
    ((to.to_flags & TOF_TS) == 0 &&
    TSTMP_LT(ticks, tp->t_badrxtwin))))
        cc_cong_signal(tp, th, CC_RTO_ERR);

This will also fix lines longer than 79 chars. IMHO, we may slightly violate style(9) and add single space indentation to highlight our three main large blocks (a && (b || c)).

glebius: I agree with Richard, better one complex if clause. The two clauses are mutually exclusive as…
tuexenAuthorUnsubmitted
Done
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Now using one and two spaces of indentation to make the expression more readable.

tuexen: Now using one and two spaces of indentation to make the expression more readable.
tuexenAuthorUnsubmitted
Done
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It was a try to break things up for improved readability by humans.

tuexen: It was a try to break things up for improved readability by humans.
* during the SYN+ACK phase, ignore * during the SYN+ACK phase, ignore
* timestamps of 0 or we could calculate a * timestamps of 0 or we could calculate a
* huge RTT and blow up the retransmit timer. * huge RTT and blow up the retransmit timer.
*/ */
if ((to.to_flags & TOF_TS) != 0 && if ((to.to_flags & TOF_TS) != 0 &&
to.to_tsecr) { to.to_tsecr) {
uint32_t t; uint32_t t;
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