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sctp: improve handling of stale cookie error causes

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* If a measure of staleness of 0 is reported, use the RTT instead.
* Ensure that we always send a cookie preservative parameter by
  rounding up during the calculation.
* If allowed, perform a round trip time measurement.
* Clear the overall error counter, since the error cause also
  acts like an ACK.

MFC after:	1 week
This commit is contained in:
Michael Tuexen 2023-04-30 11:39:32 +02:00
parent 2e7797cd9b
commit 1f0e13449b
1 changed files with 31 additions and 10 deletions
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41
sys/netinet/sctp_input.c
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@ -1133,26 +1133,47 @@ sctp_handle_error(struct sctp_chunkhdr *ch,
*/
if ((cause_length >= sizeof(struct sctp_error_stale_cookie)) &&
(SCTP_GET_STATE(stcb) == SCTP_STATE_COOKIE_ECHOED)) {
struct timeval now;
struct sctp_error_stale_cookie *stale_cookie;
uint64_t stale_time;
stale_cookie = (struct sctp_error_stale_cookie *)cause;
/* stable_time is in usec, convert to msec. */
asoc->cookie_preserve_req = ntohl(stale_cookie->stale_time) / 1000;
/* Double it to be more robust on RTX. */
asoc->cookie_preserve_req *= 2;
asoc->stale_cookie_count++;
if (asoc->stale_cookie_count >
asoc->max_init_times) {
if (asoc->stale_cookie_count > asoc->max_init_times) {
sctp_abort_notification(stcb, false, true, 0, NULL, SCTP_SO_NOT_LOCKED);
/* now free the asoc */
(void)sctp_free_assoc(stcb->sctp_ep, stcb, SCTP_NORMAL_PROC,
SCTP_FROM_SCTP_INPUT + SCTP_LOC_12);
return (-1);
}
/* blast back to INIT state */
stale_cookie = (struct sctp_error_stale_cookie *)cause;
stale_time = ntohl(stale_cookie->stale_time);
if (stale_time == 0) {
/* Use an RTT as an approximation. */
(void)SCTP_GETTIME_TIMEVAL(&now);
timevalsub(&now, &asoc->time_entered);
stale_time = (uint64_t)1000000 * (uint64_t)now.tv_sec + (uint64_t)now.tv_usec;
if (stale_time == 0) {
stale_time = 1;
}
}
/*
* stale_time is in usec, convert it to
* msec. Round upwards, to ensure that it is
* non-zero.
*/
stale_time = (stale_time + 999) / 1000;
/* Double it, to be more robust on RTX. */
stale_time = 2 * stale_time;
asoc->cookie_preserve_req = (uint32_t)stale_time;
if (asoc->overall_error_count == 0) {
sctp_calculate_rto(stcb, asoc, net, &asoc->time_entered,
SCTP_RTT_FROM_NON_DATA);
}
asoc->overall_error_count = 0;
/* Blast back to INIT state */
sctp_toss_old_cookies(stcb, &stcb->asoc);
SCTP_SET_STATE(stcb, SCTP_STATE_COOKIE_WAIT);
sctp_stop_all_cookie_timers(stcb);
SCTP_SET_STATE(stcb, SCTP_STATE_COOKIE_WAIT);
(void)SCTP_GETTIME_TIMEVAL(&asoc->time_entered);
sctp_send_initiate(stcb->sctp_ep, stcb, SCTP_SO_NOT_LOCKED);
}
break;