Mercurial > hg > nginx-quic
view src/core/ngx_times.c @ 9067:f68fdb017141 quic
QUIC: optimized sending stream response.
When a stream is created by client, it's often the case that nginx will send
immediate response on that stream. An example is HTTP/3 request stream, which
in most cases quickly replies with at least HTTP headers.
QUIC stream init handlers are called from a posted event. Output QUIC
frames are also sent to client from a posted event, called the push event.
If the push event is posted before the stream init event, then output produced
by stream may trigger sending an extra UDP datagram. To address this, push
event is now re-posted when a new stream init event is posted.
An example is handling 0-RTT packets. Client typically sends an init packet
coalesced with a 0-RTT packet. Previously, nginx replied with a padded CRYPTO
datagram, followed by a 1-RTT stream reply datagram. Now CRYPTO and STREAM
packets are coalesced in one reply datagram, which saves bandwidth.
Other examples include coalescing 1-RTT first stream response, and
MAX_STREAMS/STREAM sent in response to ACK/STREAM.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Mon, 03 Apr 2023 16:17:12 +0400 |
parents | 9e7de0547f09 |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> static ngx_msec_t ngx_monotonic_time(time_t sec, ngx_uint_t msec); /* * The time may be updated by signal handler or by several threads. * The time update operations are rare and require to hold the ngx_time_lock. * The time read operations are frequent, so they are lock-free and get time * values and strings from the current slot. Thus thread may get the corrupted * values only if it is preempted while copying and then it is not scheduled * to run more than NGX_TIME_SLOTS seconds. */ #define NGX_TIME_SLOTS 64 static ngx_uint_t slot; static ngx_atomic_t ngx_time_lock; volatile ngx_msec_t ngx_current_msec; volatile ngx_time_t *ngx_cached_time; volatile ngx_str_t ngx_cached_err_log_time; volatile ngx_str_t ngx_cached_http_time; volatile ngx_str_t ngx_cached_http_log_time; volatile ngx_str_t ngx_cached_http_log_iso8601; volatile ngx_str_t ngx_cached_syslog_time; #if !(NGX_WIN32) /* * localtime() and localtime_r() are not Async-Signal-Safe functions, therefore, * they must not be called by a signal handler, so we use the cached * GMT offset value. Fortunately the value is changed only two times a year. */ static ngx_int_t cached_gmtoff; #endif static ngx_time_t cached_time[NGX_TIME_SLOTS]; static u_char cached_err_log_time[NGX_TIME_SLOTS] [sizeof("1970/09/28 12:00:00")]; static u_char cached_http_time[NGX_TIME_SLOTS] [sizeof("Mon, 28 Sep 1970 06:00:00 GMT")]; static u_char cached_http_log_time[NGX_TIME_SLOTS] [sizeof("28/Sep/1970:12:00:00 +0600")]; static u_char cached_http_log_iso8601[NGX_TIME_SLOTS] [sizeof("1970-09-28T12:00:00+06:00")]; static u_char cached_syslog_time[NGX_TIME_SLOTS] [sizeof("Sep 28 12:00:00")]; static char *week[] = { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" }; static char *months[] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" }; void ngx_time_init(void) { ngx_cached_err_log_time.len = sizeof("1970/09/28 12:00:00") - 1; ngx_cached_http_time.len = sizeof("Mon, 28 Sep 1970 06:00:00 GMT") - 1; ngx_cached_http_log_time.len = sizeof("28/Sep/1970:12:00:00 +0600") - 1; ngx_cached_http_log_iso8601.len = sizeof("1970-09-28T12:00:00+06:00") - 1; ngx_cached_syslog_time.len = sizeof("Sep 28 12:00:00") - 1; ngx_cached_time = &cached_time[0]; ngx_time_update(); } void ngx_time_update(void) { u_char *p0, *p1, *p2, *p3, *p4; ngx_tm_t tm, gmt; time_t sec; ngx_uint_t msec; ngx_time_t *tp; struct timeval tv; if (!ngx_trylock(&ngx_time_lock)) { return; } ngx_gettimeofday(&tv); sec = tv.tv_sec; msec = tv.tv_usec / 1000; ngx_current_msec = ngx_monotonic_time(sec, msec); tp = &cached_time[slot]; if (tp->sec == sec) { tp->msec = msec; ngx_unlock(&ngx_time_lock); return; } if (slot == NGX_TIME_SLOTS - 1) { slot = 0; } else { slot++; } tp = &cached_time[slot]; tp->sec = sec; tp->msec = msec; ngx_gmtime(sec, &gmt); p0 = &cached_http_time[slot][0]; (void) ngx_sprintf(p0, "%s, %02d %s %4d %02d:%02d:%02d GMT", week[gmt.ngx_tm_wday], gmt.ngx_tm_mday, months[gmt.ngx_tm_mon - 1], gmt.ngx_tm_year, gmt.ngx_tm_hour, gmt.ngx_tm_min, gmt.ngx_tm_sec); #if (NGX_HAVE_GETTIMEZONE) tp->gmtoff = ngx_gettimezone(); ngx_gmtime(sec + tp->gmtoff * 60, &tm); #elif (NGX_HAVE_GMTOFF) ngx_localtime(sec, &tm); cached_gmtoff = (ngx_int_t) (tm.ngx_tm_gmtoff / 60); tp->gmtoff = cached_gmtoff; #else ngx_localtime(sec, &tm); cached_gmtoff = ngx_timezone(tm.ngx_tm_isdst); tp->gmtoff = cached_gmtoff; #endif p1 = &cached_err_log_time[slot][0]; (void) ngx_sprintf(p1, "%4d/%02d/%02d %02d:%02d:%02d", tm.ngx_tm_year, tm.ngx_tm_mon, tm.ngx_tm_mday, tm.ngx_tm_hour, tm.ngx_tm_min, tm.ngx_tm_sec); p2 = &cached_http_log_time[slot][0]; (void) ngx_sprintf(p2, "%02d/%s/%d:%02d:%02d:%02d %c%02i%02i", tm.ngx_tm_mday, months[tm.ngx_tm_mon - 1], tm.ngx_tm_year, tm.ngx_tm_hour, tm.ngx_tm_min, tm.ngx_tm_sec, tp->gmtoff < 0 ? '-' : '+', ngx_abs(tp->gmtoff / 60), ngx_abs(tp->gmtoff % 60)); p3 = &cached_http_log_iso8601[slot][0]; (void) ngx_sprintf(p3, "%4d-%02d-%02dT%02d:%02d:%02d%c%02i:%02i", tm.ngx_tm_year, tm.ngx_tm_mon, tm.ngx_tm_mday, tm.ngx_tm_hour, tm.ngx_tm_min, tm.ngx_tm_sec, tp->gmtoff < 0 ? '-' : '+', ngx_abs(tp->gmtoff / 60), ngx_abs(tp->gmtoff % 60)); p4 = &cached_syslog_time[slot][0]; (void) ngx_sprintf(p4, "%s %2d %02d:%02d:%02d", months[tm.ngx_tm_mon - 1], tm.ngx_tm_mday, tm.ngx_tm_hour, tm.ngx_tm_min, tm.ngx_tm_sec); ngx_memory_barrier(); ngx_cached_time = tp; ngx_cached_http_time.data = p0; ngx_cached_err_log_time.data = p1; ngx_cached_http_log_time.data = p2; ngx_cached_http_log_iso8601.data = p3; ngx_cached_syslog_time.data = p4; ngx_unlock(&ngx_time_lock); } static ngx_msec_t ngx_monotonic_time(time_t sec, ngx_uint_t msec) { #if (NGX_HAVE_CLOCK_MONOTONIC) struct timespec ts; #if defined(CLOCK_MONOTONIC_FAST) clock_gettime(CLOCK_MONOTONIC_FAST, &ts); #else clock_gettime(CLOCK_MONOTONIC, &ts); #endif sec = ts.tv_sec; msec = ts.tv_nsec / 1000000; #endif return (ngx_msec_t) sec * 1000 + msec; } #if !(NGX_WIN32) void ngx_time_sigsafe_update(void) { u_char *p, *p2; ngx_tm_t tm; time_t sec; ngx_time_t *tp; struct timeval tv; if (!ngx_trylock(&ngx_time_lock)) { return; } ngx_gettimeofday(&tv); sec = tv.tv_sec; tp = &cached_time[slot]; if (tp->sec == sec) { ngx_unlock(&ngx_time_lock); return; } if (slot == NGX_TIME_SLOTS - 1) { slot = 0; } else { slot++; } tp = &cached_time[slot]; tp->sec = 0; ngx_gmtime(sec + cached_gmtoff * 60, &tm); p = &cached_err_log_time[slot][0]; (void) ngx_sprintf(p, "%4d/%02d/%02d %02d:%02d:%02d", tm.ngx_tm_year, tm.ngx_tm_mon, tm.ngx_tm_mday, tm.ngx_tm_hour, tm.ngx_tm_min, tm.ngx_tm_sec); p2 = &cached_syslog_time[slot][0]; (void) ngx_sprintf(p2, "%s %2d %02d:%02d:%02d", months[tm.ngx_tm_mon - 1], tm.ngx_tm_mday, tm.ngx_tm_hour, tm.ngx_tm_min, tm.ngx_tm_sec); ngx_memory_barrier(); ngx_cached_err_log_time.data = p; ngx_cached_syslog_time.data = p2; ngx_unlock(&ngx_time_lock); } #endif u_char * ngx_http_time(u_char *buf, time_t t) { ngx_tm_t tm; ngx_gmtime(t, &tm); return ngx_sprintf(buf, "%s, %02d %s %4d %02d:%02d:%02d GMT", week[tm.ngx_tm_wday], tm.ngx_tm_mday, months[tm.ngx_tm_mon - 1], tm.ngx_tm_year, tm.ngx_tm_hour, tm.ngx_tm_min, tm.ngx_tm_sec); } u_char * ngx_http_cookie_time(u_char *buf, time_t t) { ngx_tm_t tm; ngx_gmtime(t, &tm); /* * Netscape 3.x does not understand 4-digit years at all and * 2-digit years more than "37" */ return ngx_sprintf(buf, (tm.ngx_tm_year > 2037) ? "%s, %02d-%s-%d %02d:%02d:%02d GMT": "%s, %02d-%s-%02d %02d:%02d:%02d GMT", week[tm.ngx_tm_wday], tm.ngx_tm_mday, months[tm.ngx_tm_mon - 1], (tm.ngx_tm_year > 2037) ? tm.ngx_tm_year: tm.ngx_tm_year % 100, tm.ngx_tm_hour, tm.ngx_tm_min, tm.ngx_tm_sec); } void ngx_gmtime(time_t t, ngx_tm_t *tp) { ngx_int_t yday; ngx_uint_t sec, min, hour, mday, mon, year, wday, days, leap; /* the calculation is valid for positive time_t only */ if (t < 0) { t = 0; } days = t / 86400; sec = t % 86400; /* * no more than 4 year digits supported, * truncate to December 31, 9999, 23:59:59 */ if (days > 2932896) { days = 2932896; sec = 86399; } /* January 1, 1970 was Thursday */ wday = (4 + days) % 7; hour = sec / 3600; sec %= 3600; min = sec / 60; sec %= 60; /* * the algorithm based on Gauss' formula, * see src/core/ngx_parse_time.c */ /* days since March 1, 1 BC */ days = days - (31 + 28) + 719527; /* * The "days" should be adjusted to 1 only, however, some March 1st's go * to previous year, so we adjust them to 2. This causes also shift of the * last February days to next year, but we catch the case when "yday" * becomes negative. */ year = (days + 2) * 400 / (365 * 400 + 100 - 4 + 1); yday = days - (365 * year + year / 4 - year / 100 + year / 400); if (yday < 0) { leap = (year % 4 == 0) && (year % 100 || (year % 400 == 0)); yday = 365 + leap + yday; year--; } /* * The empirical formula that maps "yday" to month. * There are at least 10 variants, some of them are: * mon = (yday + 31) * 15 / 459 * mon = (yday + 31) * 17 / 520 * mon = (yday + 31) * 20 / 612 */ mon = (yday + 31) * 10 / 306; /* the Gauss' formula that evaluates days before the month */ mday = yday - (367 * mon / 12 - 30) + 1; if (yday >= 306) { year++; mon -= 10; /* * there is no "yday" in Win32 SYSTEMTIME * * yday -= 306; */ } else { mon += 2; /* * there is no "yday" in Win32 SYSTEMTIME * * yday += 31 + 28 + leap; */ } tp->ngx_tm_sec = (ngx_tm_sec_t) sec; tp->ngx_tm_min = (ngx_tm_min_t) min; tp->ngx_tm_hour = (ngx_tm_hour_t) hour; tp->ngx_tm_mday = (ngx_tm_mday_t) mday; tp->ngx_tm_mon = (ngx_tm_mon_t) mon; tp->ngx_tm_year = (ngx_tm_year_t) year; tp->ngx_tm_wday = (ngx_tm_wday_t) wday; } time_t ngx_next_time(time_t when) { time_t now, next; struct tm tm; now = ngx_time(); ngx_libc_localtime(now, &tm); tm.tm_hour = (int) (when / 3600); when %= 3600; tm.tm_min = (int) (when / 60); tm.tm_sec = (int) (when % 60); next = mktime(&tm); if (next == -1) { return -1; } if (next - now > 0) { return next; } tm.tm_mday++; /* mktime() should normalize a date (Jan 32, etc) */ next = mktime(&tm); if (next != -1) { return next; } return -1; }