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| author | Roman Arutyunyan <arut@nginx.com> | 2025-03-10 12:19:25 +0400 |
|---|---|---|
| committer | Roman Arutyunyan <arutyunyan.roman@gmail.com> | 2025-04-15 19:01:36 +0400 |
| commit | 1e883a40db98b70e422ff8e4d1d0e87e3f8ccaa5 (patch) | |
| tree | 2eb1f21e6e3cad971c16534c482b21f0cadc633e | |
| parent | 38236bf74f3e5728eeea488bef381c61842ac1d2 (diff) | |
| download | nginx-1e883a40db98b70e422ff8e4d1d0e87e3f8ccaa5.tar.gz nginx-1e883a40db98b70e422ff8e4d1d0e87e3f8ccaa5.zip | |
QUIC: ngx_msec_t overflow protection.
On some systems the value of ngx_current_msec is derived from monotonic
clock, for which the following is defined by POSIX:
For this clock, the value returned by clock_gettime() represents
the amount of time (in seconds and nanoseconds) since an unspecified
point in the past.
As as result, overflow protection is needed when comparing two ngx_msec_t.
The change adds such protection to the ngx_quic_detect_lost() function.
| -rw-r--r-- | src/event/quic/ngx_event_quic_ack.c | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/src/event/quic/ngx_event_quic_ack.c b/src/event/quic/ngx_event_quic_ack.c index 29c5bfed1..a6f34348b 100644 --- a/src/event/quic/ngx_event_quic_ack.c +++ b/src/event/quic/ngx_event_quic_ack.c @@ -449,9 +449,10 @@ ngx_quic_detect_lost(ngx_connection_t *c, ngx_quic_ack_stat_t *st) now = ngx_current_msec; thr = ngx_quic_lost_threshold(qc); - /* send time of lost packets across all send contexts */ - oldest = NGX_TIMER_INFINITE; - newest = NGX_TIMER_INFINITE; +#if (NGX_SUPPRESS_WARN) + oldest = now; + newest = now; +#endif nlost = 0; @@ -484,13 +485,17 @@ ngx_quic_detect_lost(ngx_connection_t *c, ngx_quic_ack_stat_t *st) break; } - if (start->send_time > qc->first_rtt) { + if ((ngx_msec_int_t) (start->send_time - qc->first_rtt) > 0) { - if (oldest == NGX_TIMER_INFINITE || start->send_time < oldest) { + if (nlost == 0 + || (ngx_msec_int_t) (start->send_time - oldest) < 0) + { oldest = start->send_time; } - if (newest == NGX_TIMER_INFINITE || start->send_time > newest) { + if (nlost == 0 + || (ngx_msec_int_t) (start->send_time - newest) > 0) + { newest = start->send_time; } @@ -511,8 +516,9 @@ ngx_quic_detect_lost(ngx_connection_t *c, ngx_quic_ack_stat_t *st) * latest ACK frame. */ - if (st && nlost >= 2 && (st->newest < oldest || st->oldest > newest)) { - + if (st && nlost >= 2 && ((ngx_msec_int_t) (st->newest - oldest) < 0 + || (ngx_msec_int_t) (st->oldest - newest) > 0)) + { if (newest - oldest > ngx_quic_pcg_duration(c)) { ngx_quic_persistent_congestion(c); } |