[nginx] Added "keepalive_min_timeout" directive.
noreply at nginx.com
noreply at nginx.com
Wed Feb 5 10:09:02 UTC 2025
details: https://github.com/nginx/nginx/commit/22a2a225ba87029f0e7bbc09a80ff7cdad23399d
branches: master
commit: 22a2a225ba87029f0e7bbc09a80ff7cdad23399d
user: Roman Arutyunyan <arut at nginx.com>
date: Wed, 15 Jan 2025 12:42:39 +0400
description:
Added "keepalive_min_timeout" directive.
The directive sets a timeout during which a keepalive connection will
not be closed by nginx for connection reuse or graceful shutdown.
The change allows clients that send multiple requests over the same
connection without delay or with a small delay between them, to avoid
receiving a TCP RST in response to one of them. This excludes network
issues and non-graceful shutdown. As a side-effect, it also addresses
the TCP reset problem described in RFC 9112, Section 9.6, when the last
sent HTTP response could be damaged by a followup TCP RST. It is important
for non-idempotent requests, which cannot be retried by client.
It is not recommended to set keepalive_min_timeout to large values as
this can introduce an additional delay during graceful shutdown and may
restrict nginx from effective connection reuse.
---
src/http/ngx_http_core_module.c | 10 +++++++++
src/http/ngx_http_core_module.h | 1 +
src/http/ngx_http_request.c | 50 +++++++++++++++++++++++++++++++++++------
src/http/ngx_http_request.h | 2 ++
4 files changed, 56 insertions(+), 7 deletions(-)
diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
index 033a3bf64..a1540c018 100644
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -509,6 +509,13 @@ static ngx_command_t ngx_http_core_commands[] = {
0,
NULL },
+ { ngx_string("keepalive_min_timeout"),
+ NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+ ngx_conf_set_msec_slot,
+ NGX_HTTP_LOC_CONF_OFFSET,
+ offsetof(ngx_http_core_loc_conf_t, keepalive_min_timeout),
+ NULL },
+
{ ngx_string("keepalive_requests"),
NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
ngx_conf_set_num_slot,
@@ -3606,6 +3613,7 @@ ngx_http_core_create_loc_conf(ngx_conf_t *cf)
clcf->keepalive_time = NGX_CONF_UNSET_MSEC;
clcf->keepalive_timeout = NGX_CONF_UNSET_MSEC;
clcf->keepalive_header = NGX_CONF_UNSET;
+ clcf->keepalive_min_timeout = NGX_CONF_UNSET_MSEC;
clcf->keepalive_requests = NGX_CONF_UNSET_UINT;
clcf->lingering_close = NGX_CONF_UNSET_UINT;
clcf->lingering_time = NGX_CONF_UNSET_MSEC;
@@ -3844,6 +3852,8 @@ ngx_http_core_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
prev->keepalive_timeout, 75000);
ngx_conf_merge_sec_value(conf->keepalive_header,
prev->keepalive_header, 0);
+ ngx_conf_merge_msec_value(conf->keepalive_min_timeout,
+ prev->keepalive_min_timeout, 0);
ngx_conf_merge_uint_value(conf->keepalive_requests,
prev->keepalive_requests, 1000);
ngx_conf_merge_uint_value(conf->lingering_close,
diff --git a/src/http/ngx_http_core_module.h b/src/http/ngx_http_core_module.h
index 765e7ff60..e7e266bf8 100644
--- a/src/http/ngx_http_core_module.h
+++ b/src/http/ngx_http_core_module.h
@@ -370,6 +370,7 @@ struct ngx_http_core_loc_conf_s {
ngx_msec_t send_timeout; /* send_timeout */
ngx_msec_t keepalive_time; /* keepalive_time */
ngx_msec_t keepalive_timeout; /* keepalive_timeout */
+ ngx_msec_t keepalive_min_timeout; /* keepalive_min_timeout */
ngx_msec_t lingering_time; /* lingering_time */
ngx_msec_t lingering_timeout; /* lingering_timeout */
ngx_msec_t resolver_timeout; /* resolver_timeout */
diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
index f44c9e79b..0be9da95e 100644
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -2799,6 +2799,13 @@ ngx_http_finalize_connection(ngx_http_request_t *r)
r->lingering_close = 1;
}
+ if (r->keepalive
+ && clcf->keepalive_min_timeout > 0)
+ {
+ ngx_http_set_keepalive(r);
+ return;
+ }
+
if (!ngx_terminate
&& !ngx_exiting
&& r->keepalive
@@ -3301,10 +3308,22 @@ ngx_http_set_keepalive(ngx_http_request_t *r)
r->http_state = NGX_HTTP_KEEPALIVE_STATE;
#endif
- c->idle = 1;
- ngx_reusable_connection(c, 1);
+ if (clcf->keepalive_min_timeout == 0) {
+ c->idle = 1;
+ ngx_reusable_connection(c, 1);
+ }
+
+ if (clcf->keepalive_min_timeout > 0
+ && clcf->keepalive_timeout > clcf->keepalive_min_timeout)
+ {
+ hc->keepalive_timeout = clcf->keepalive_timeout
+ - clcf->keepalive_min_timeout;
+
+ } else {
+ hc->keepalive_timeout = 0;
+ }
- ngx_add_timer(rev, clcf->keepalive_timeout);
+ ngx_add_timer(rev, clcf->keepalive_timeout - hc->keepalive_timeout);
if (rev->ready) {
ngx_post_event(rev, &ngx_posted_events);
@@ -3315,15 +3334,32 @@ ngx_http_set_keepalive(ngx_http_request_t *r)
static void
ngx_http_keepalive_handler(ngx_event_t *rev)
{
- size_t size;
- ssize_t n;
- ngx_buf_t *b;
- ngx_connection_t *c;
+ size_t size;
+ ssize_t n;
+ ngx_buf_t *b;
+ ngx_connection_t *c;
+ ngx_http_connection_t *hc;
c = rev->data;
+ hc = c->data;
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "http keepalive handler");
+ if (!ngx_terminate
+ && !ngx_exiting
+ && rev->timedout
+ && hc->keepalive_timeout > 0)
+ {
+ c->idle = 1;
+ ngx_reusable_connection(c, 1);
+
+ ngx_add_timer(rev, hc->keepalive_timeout);
+
+ hc->keepalive_timeout = 0;
+ rev->timedout = 0;
+ return;
+ }
+
if (rev->timedout || c->close) {
ngx_http_close_connection(c);
return;
diff --git a/src/http/ngx_http_request.h b/src/http/ngx_http_request.h
index 65c8333f8..9407f46ae 100644
--- a/src/http/ngx_http_request.h
+++ b/src/http/ngx_http_request.h
@@ -329,6 +329,8 @@ typedef struct {
ngx_chain_t *free;
+ ngx_msec_t keepalive_timeout;
+
unsigned ssl:1;
unsigned proxy_protocol:1;
} ngx_http_connection_t;
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