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Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,252 @@ | ||
What we do now: | ||
We use a static record size of 4K. This gives a good balance of latency and | ||
throughput. | ||
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Optimize latency: | ||
By initialy sending small (1 TCP segment) sized records, we are able to avoid | ||
HoL blocking of the first byte. This means TTFB is sometime lower by a whole | ||
RTT. | ||
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Optimizing throughput: | ||
By sending increasingly larger records later in the connection, when HoL is not | ||
a problem, we reduce the overhead of TLS record (29 bytes per record with | ||
GCM/CHACHA-POLY). | ||
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Logic: | ||
Start each connection with small records (1369 byte default, change with | ||
ssl_dyn_rec_size_lo). After a given number of records (40, change with | ||
ssl_dyn_rec_threshold) start sending larger records (4229, ssl_dyn_rec_size_hi). | ||
Eventually after the same number of records, start sending the largest records | ||
(ssl_buffer_size). | ||
In case the connection idles for a given amount of time (1s, | ||
ssl_dyn_rec_timeout), the process repeats itself (i.e. begin sending small | ||
records again). | ||
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Upstream source: | ||
https://github.com/cloudflare/sslconfig/blob/master/patches/nginx__dynamic_tls_records.patch | ||
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--- a/src/event/ngx_event_openssl.c | ||
+++ b/src/event/ngx_event_openssl.c | ||
@@ -1131,6 +1131,7 @@ | ||
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sc->buffer = ((flags & NGX_SSL_BUFFER) != 0); | ||
sc->buffer_size = ssl->buffer_size; | ||
+ sc->dyn_rec = ssl->dyn_rec; | ||
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sc->session_ctx = ssl->ctx; | ||
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@@ -1669,6 +1670,41 @@ | ||
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for ( ;; ) { | ||
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+ /* Dynamic record resizing: | ||
+ We want the initial records to fit into one TCP segment | ||
+ so we don't get TCP HoL blocking due to TCP Slow Start. | ||
+ A connection always starts with small records, but after | ||
+ a given amount of records sent, we make the records larger | ||
+ to reduce header overhead. | ||
+ After a connection has idled for a given timeout, begin | ||
+ the process from the start. The actual parameters are | ||
+ configurable. If dyn_rec_timeout is 0, we assume dyn_rec is off. */ | ||
+ | ||
+ if (c->ssl->dyn_rec.timeout > 0 ) { | ||
+ | ||
+ if (ngx_current_msec - c->ssl->dyn_rec_last_write > | ||
+ c->ssl->dyn_rec.timeout) | ||
+ { | ||
+ buf->end = buf->start + c->ssl->dyn_rec.size_lo; | ||
+ c->ssl->dyn_rec_records_sent = 0; | ||
+ | ||
+ } else { | ||
+ if (c->ssl->dyn_rec_records_sent > | ||
+ c->ssl->dyn_rec.threshold * 2) | ||
+ { | ||
+ buf->end = buf->start + c->ssl->buffer_size; | ||
+ | ||
+ } else if (c->ssl->dyn_rec_records_sent > | ||
+ c->ssl->dyn_rec.threshold) | ||
+ { | ||
+ buf->end = buf->start + c->ssl->dyn_rec.size_hi; | ||
+ | ||
+ } else { | ||
+ buf->end = buf->start + c->ssl->dyn_rec.size_lo; | ||
+ } | ||
+ } | ||
+ } | ||
+ | ||
while (in && buf->last < buf->end && send < limit) { | ||
if (in->buf->last_buf || in->buf->flush) { | ||
flush = 1; | ||
@@ -1770,6 +1806,9 @@ | ||
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if (n > 0) { | ||
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+ c->ssl->dyn_rec_records_sent++; | ||
+ c->ssl->dyn_rec_last_write = ngx_current_msec; | ||
+ | ||
if (c->ssl->saved_read_handler) { | ||
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c->read->handler = c->ssl->saved_read_handler; | ||
--- a/src/event/ngx_event_openssl.h | ||
+++ b/src/event/ngx_event_openssl.h | ||
@@ -54,10 +54,19 @@ | ||
#endif | ||
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+typedef struct { | ||
+ ngx_msec_t timeout; | ||
+ ngx_uint_t threshold; | ||
+ size_t size_lo; | ||
+ size_t size_hi; | ||
+} ngx_ssl_dyn_rec_t; | ||
+ | ||
+ | ||
struct ngx_ssl_s { | ||
SSL_CTX *ctx; | ||
ngx_log_t *log; | ||
size_t buffer_size; | ||
+ ngx_ssl_dyn_rec_t dyn_rec; | ||
}; | ||
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@@ -80,6 +89,10 @@ | ||
unsigned no_wait_shutdown:1; | ||
unsigned no_send_shutdown:1; | ||
unsigned handshake_buffer_set:1; | ||
+ | ||
+ ngx_ssl_dyn_rec_t dyn_rec; | ||
+ ngx_msec_t dyn_rec_last_write; | ||
+ ngx_uint_t dyn_rec_records_sent; | ||
}; | ||
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@@ -89,7 +102,7 @@ | ||
#define NGX_SSL_DFLT_BUILTIN_SCACHE -5 | ||
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-#define NGX_SSL_MAX_SESSION_SIZE 4096 | ||
+#define NGX_SSL_MAX_SESSION_SIZE 16384 | ||
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typedef struct ngx_ssl_sess_id_s ngx_ssl_sess_id_t; | ||
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--- a/src/http/modules/ngx_http_ssl_module.c | ||
+++ b/src/http/modules/ngx_http_ssl_module.c | ||
@@ -233,6 +233,41 @@ | ||
offsetof(ngx_http_ssl_srv_conf_t, stapling_verify), | ||
NULL }, | ||
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+ { ngx_string("ssl_dyn_rec_enable"), | ||
+ NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_FLAG, | ||
+ ngx_conf_set_flag_slot, | ||
+ NGX_HTTP_SRV_CONF_OFFSET, | ||
+ offsetof(ngx_http_ssl_srv_conf_t, dyn_rec_enable), | ||
+ NULL }, | ||
+ | ||
+ { ngx_string("ssl_dyn_rec_timeout"), | ||
+ NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_FLAG, | ||
+ ngx_conf_set_msec_slot, | ||
+ NGX_HTTP_SRV_CONF_OFFSET, | ||
+ offsetof(ngx_http_ssl_srv_conf_t, dyn_rec_timeout), | ||
+ NULL }, | ||
+ | ||
+ { ngx_string("ssl_dyn_rec_size_lo"), | ||
+ NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_FLAG, | ||
+ ngx_conf_set_size_slot, | ||
+ NGX_HTTP_SRV_CONF_OFFSET, | ||
+ offsetof(ngx_http_ssl_srv_conf_t, dyn_rec_size_lo), | ||
+ NULL }, | ||
+ | ||
+ { ngx_string("ssl_dyn_rec_size_hi"), | ||
+ NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_FLAG, | ||
+ ngx_conf_set_size_slot, | ||
+ NGX_HTTP_SRV_CONF_OFFSET, | ||
+ offsetof(ngx_http_ssl_srv_conf_t, dyn_rec_size_hi), | ||
+ NULL }, | ||
+ | ||
+ { ngx_string("ssl_dyn_rec_threshold"), | ||
+ NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_FLAG, | ||
+ ngx_conf_set_num_slot, | ||
+ NGX_HTTP_SRV_CONF_OFFSET, | ||
+ offsetof(ngx_http_ssl_srv_conf_t, dyn_rec_threshold), | ||
+ NULL }, | ||
+ | ||
ngx_null_command | ||
}; | ||
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@@ -533,6 +568,11 @@ | ||
sscf->session_ticket_keys = NGX_CONF_UNSET_PTR; | ||
sscf->stapling = NGX_CONF_UNSET; | ||
sscf->stapling_verify = NGX_CONF_UNSET; | ||
+ sscf->dyn_rec_enable = NGX_CONF_UNSET; | ||
+ sscf->dyn_rec_timeout = NGX_CONF_UNSET_MSEC; | ||
+ sscf->dyn_rec_size_lo = NGX_CONF_UNSET_SIZE; | ||
+ sscf->dyn_rec_size_hi = NGX_CONF_UNSET_SIZE; | ||
+ sscf->dyn_rec_threshold = NGX_CONF_UNSET_UINT; | ||
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return sscf; | ||
} | ||
@@ -598,6 +638,20 @@ | ||
ngx_conf_merge_str_value(conf->stapling_responder, | ||
prev->stapling_responder, ""); | ||
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+ ngx_conf_merge_value(conf->dyn_rec_enable, prev->dyn_rec_enable, 0); | ||
+ ngx_conf_merge_msec_value(conf->dyn_rec_timeout, prev->dyn_rec_timeout, | ||
+ 1000); | ||
+ /* Default sizes for the dynamic record sizes are defined to fit maximal | ||
+ TLS + IPv6 overhead in a single TCP segment for lo and 3 segments for hi: | ||
+ 1369 = 1500 - 40 (IP) - 20 (TCP) - 10 (Time) - 61 (Max TLS overhead) */ | ||
+ ngx_conf_merge_size_value(conf->dyn_rec_size_lo, prev->dyn_rec_size_lo, | ||
+ 1369); | ||
+ /* 4229 = (1500 - 40 - 20 - 10) * 3 - 61 */ | ||
+ ngx_conf_merge_size_value(conf->dyn_rec_size_hi, prev->dyn_rec_size_hi, | ||
+ 4229); | ||
+ ngx_conf_merge_uint_value(conf->dyn_rec_threshold, prev->dyn_rec_threshold, | ||
+ 40); | ||
+ | ||
conf->ssl.log = cf->log; | ||
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if (conf->enable) { | ||
@@ -778,6 +832,28 @@ | ||
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} | ||
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+ if (conf->dyn_rec_enable) { | ||
+ conf->ssl.dyn_rec.timeout = conf->dyn_rec_timeout; | ||
+ conf->ssl.dyn_rec.threshold = conf->dyn_rec_threshold; | ||
+ | ||
+ if (conf->buffer_size > conf->dyn_rec_size_lo) { | ||
+ conf->ssl.dyn_rec.size_lo = conf->dyn_rec_size_lo; | ||
+ | ||
+ } else { | ||
+ conf->ssl.dyn_rec.size_lo = conf->buffer_size; | ||
+ } | ||
+ | ||
+ if (conf->buffer_size > conf->dyn_rec_size_hi) { | ||
+ conf->ssl.dyn_rec.size_hi = conf->dyn_rec_size_hi; | ||
+ | ||
+ } else { | ||
+ conf->ssl.dyn_rec.size_hi = conf->buffer_size; | ||
+ } | ||
+ | ||
+ } else { | ||
+ conf->ssl.dyn_rec.timeout = 0; | ||
+ } | ||
+ | ||
return NGX_CONF_OK; | ||
} | ||
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--- a/src/http/modules/ngx_http_ssl_module.h | ||
+++ b/src/http/modules/ngx_http_ssl_module.h | ||
@@ -57,6 +57,12 @@ | ||
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u_char *file; | ||
ngx_uint_t line; | ||
+ | ||
+ ngx_flag_t dyn_rec_enable; | ||
+ ngx_msec_t dyn_rec_timeout; | ||
+ size_t dyn_rec_size_lo; | ||
+ size_t dyn_rec_size_hi; | ||
+ ngx_uint_t dyn_rec_threshold; | ||
} ngx_http_ssl_srv_conf_t; | ||
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