Mercurial > hg > nginx
view src/http/modules/ngx_http_upstream_keepalive_module.c @ 9203:0de20f43db25
Fixed request termination with AIO and subrequests (ticket #2555).
When a request was terminated due to an error via ngx_http_terminate_request()
while an AIO operation was running in a subrequest, various issues were
observed. This happened because ngx_http_request_finalizer() was only set
in the subrequest where ngx_http_terminate_request() was called, but not
in the subrequest where the AIO operation was running. After completion
of the AIO operation normal processing of the subrequest was resumed, leading
to issues.
In particular, in case of the upstream module, termination of the request
called upstream cleanup, which closed the upstream connection. Attempts to
further work with the upstream connection after AIO operation completion
resulted in segfaults in ngx_ssl_recv(), "readv() failed (9: Bad file
descriptor) while reading upstream" errors, or socket leaks.
In ticket #2555, issues were observed with the following configuration
with cache background update (with thread writing instrumented to
introduce a delay, when a client closes the connection during an update):
location = /background-and-aio-write {
proxy_pass ...
proxy_cache one;
proxy_cache_valid 200 1s;
proxy_cache_background_update on;
proxy_cache_use_stale updating;
aio threads;
aio_write on;
limit_rate 1000;
}
Similarly, the same issue can be seen with SSI, and can be caused by
errors in subrequests, such as in the following configuration
(where "/proxy" uses AIO, and "/sleep" returns 444 after some delay,
causing request termination):
location = /ssi-active-boom {
ssi on;
ssi_types *;
return 200 '
<!--#include virtual="/proxy" -->
<!--#include virtual="/sleep" -->
';
limit_rate 1000;
}
Or the same with both AIO operation and the error in non-active subrequests
(which needs slightly different handling, see below):
location = /ssi-non-active-boom {
ssi on;
ssi_types *;
return 200 '
<!--#include virtual="/static" -->
<!--#include virtual="/proxy" -->
<!--#include virtual="/sleep" -->
';
limit_rate 1000;
}
Similarly, issues can be observed with just static files. However,
with static files potential impact is limited due to timeout safeguards
in ngx_http_writer(), and the fact that c->error is set during request
termination.
In a simple configuration with an AIO operation in the active subrequest,
such as in the following configuration, the connection is closed right
after completion of the AIO operation anyway, since ngx_http_writer()
tries to write to the connection and fails due to c->error set:
location = /ssi-active-static-boom {
ssi on;
ssi_types *;
return 200 '
<!--#include virtual="/static-aio" -->
<!--#include virtual="/sleep" -->
';
limit_rate 1000;
}
In the following configuration, with an AIO operation in a non-active
subrequest, the connection is closed only after send_timeout expires:
location = /ssi-non-active-static-boom {
ssi on;
ssi_types *;
return 200 '
<!--#include virtual="/static" -->
<!--#include virtual="/static-aio" -->
<!--#include virtual="/sleep" -->
';
limit_rate 1000;
}
Fix is to introduce r->main->terminated flag, which is to be checked
by AIO event handlers when the r->main->blocked counter is decremented.
When the flag is set, handlers are expected to wake up the connection
instead of the subrequest (which might be already cleaned up).
Additionally, now ngx_http_request_finalizer() is always set in the
active subrequest, so waking up the connection properly finalizes the
request even if termination happened in a non-active subrequest.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Tue, 30 Jan 2024 03:20:05 +0300 |
parents | 82e174e47663 |
children |
line wrap: on
line source
/* * Copyright (C) Maxim Dounin * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef struct { ngx_uint_t max_cached; ngx_uint_t requests; ngx_msec_t time; ngx_msec_t timeout; ngx_queue_t cache; ngx_queue_t free; ngx_http_upstream_init_pt original_init_upstream; ngx_http_upstream_init_peer_pt original_init_peer; } ngx_http_upstream_keepalive_srv_conf_t; typedef struct { ngx_http_upstream_keepalive_srv_conf_t *conf; ngx_queue_t queue; ngx_connection_t *connection; socklen_t socklen; ngx_sockaddr_t sockaddr; } ngx_http_upstream_keepalive_cache_t; typedef struct { ngx_http_upstream_keepalive_srv_conf_t *conf; ngx_http_upstream_t *upstream; void *data; ngx_event_get_peer_pt original_get_peer; ngx_event_free_peer_pt original_free_peer; #if (NGX_HTTP_SSL) ngx_event_set_peer_session_pt original_set_session; ngx_event_save_peer_session_pt original_save_session; #endif } ngx_http_upstream_keepalive_peer_data_t; static ngx_int_t ngx_http_upstream_init_keepalive_peer(ngx_http_request_t *r, ngx_http_upstream_srv_conf_t *us); static ngx_int_t ngx_http_upstream_get_keepalive_peer(ngx_peer_connection_t *pc, void *data); static void ngx_http_upstream_free_keepalive_peer(ngx_peer_connection_t *pc, void *data, ngx_uint_t state); static void ngx_http_upstream_keepalive_dummy_handler(ngx_event_t *ev); static void ngx_http_upstream_keepalive_close_handler(ngx_event_t *ev); static void ngx_http_upstream_keepalive_close(ngx_connection_t *c); #if (NGX_HTTP_SSL) static ngx_int_t ngx_http_upstream_keepalive_set_session( ngx_peer_connection_t *pc, void *data); static void ngx_http_upstream_keepalive_save_session(ngx_peer_connection_t *pc, void *data); #endif static void *ngx_http_upstream_keepalive_create_conf(ngx_conf_t *cf); static char *ngx_http_upstream_keepalive(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_command_t ngx_http_upstream_keepalive_commands[] = { { ngx_string("keepalive"), NGX_HTTP_UPS_CONF|NGX_CONF_TAKE1, ngx_http_upstream_keepalive, NGX_HTTP_SRV_CONF_OFFSET, 0, NULL }, { ngx_string("keepalive_time"), NGX_HTTP_UPS_CONF|NGX_CONF_TAKE1, ngx_conf_set_msec_slot, NGX_HTTP_SRV_CONF_OFFSET, offsetof(ngx_http_upstream_keepalive_srv_conf_t, time), NULL }, { ngx_string("keepalive_timeout"), NGX_HTTP_UPS_CONF|NGX_CONF_TAKE1, ngx_conf_set_msec_slot, NGX_HTTP_SRV_CONF_OFFSET, offsetof(ngx_http_upstream_keepalive_srv_conf_t, timeout), NULL }, { ngx_string("keepalive_requests"), NGX_HTTP_UPS_CONF|NGX_CONF_TAKE1, ngx_conf_set_num_slot, NGX_HTTP_SRV_CONF_OFFSET, offsetof(ngx_http_upstream_keepalive_srv_conf_t, requests), NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_upstream_keepalive_module_ctx = { NULL, /* preconfiguration */ NULL, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ ngx_http_upstream_keepalive_create_conf, /* create server configuration */ NULL, /* merge server configuration */ NULL, /* create location configuration */ NULL /* merge location configuration */ }; ngx_module_t ngx_http_upstream_keepalive_module = { NGX_MODULE_V1, &ngx_http_upstream_keepalive_module_ctx, /* module context */ ngx_http_upstream_keepalive_commands, /* module directives */ NGX_HTTP_MODULE, /* module type */ NULL, /* init master */ NULL, /* init module */ NULL, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ NULL, /* exit process */ NULL, /* exit master */ NGX_MODULE_V1_PADDING }; static ngx_int_t ngx_http_upstream_init_keepalive(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us) { ngx_uint_t i; ngx_http_upstream_keepalive_srv_conf_t *kcf; ngx_http_upstream_keepalive_cache_t *cached; ngx_log_debug0(NGX_LOG_DEBUG_HTTP, cf->log, 0, "init keepalive"); kcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_keepalive_module); ngx_conf_init_msec_value(kcf->time, 3600000); ngx_conf_init_msec_value(kcf->timeout, 60000); ngx_conf_init_uint_value(kcf->requests, 1000); if (kcf->original_init_upstream(cf, us) != NGX_OK) { return NGX_ERROR; } kcf->original_init_peer = us->peer.init; us->peer.init = ngx_http_upstream_init_keepalive_peer; /* allocate cache items and add to free queue */ cached = ngx_pcalloc(cf->pool, sizeof(ngx_http_upstream_keepalive_cache_t) * kcf->max_cached); if (cached == NULL) { return NGX_ERROR; } ngx_queue_init(&kcf->cache); ngx_queue_init(&kcf->free); for (i = 0; i < kcf->max_cached; i++) { ngx_queue_insert_head(&kcf->free, &cached[i].queue); cached[i].conf = kcf; } return NGX_OK; } static ngx_int_t ngx_http_upstream_init_keepalive_peer(ngx_http_request_t *r, ngx_http_upstream_srv_conf_t *us) { ngx_http_upstream_keepalive_peer_data_t *kp; ngx_http_upstream_keepalive_srv_conf_t *kcf; ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "init keepalive peer"); kcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_keepalive_module); kp = ngx_palloc(r->pool, sizeof(ngx_http_upstream_keepalive_peer_data_t)); if (kp == NULL) { return NGX_ERROR; } if (kcf->original_init_peer(r, us) != NGX_OK) { return NGX_ERROR; } kp->conf = kcf; kp->upstream = r->upstream; kp->data = r->upstream->peer.data; kp->original_get_peer = r->upstream->peer.get; kp->original_free_peer = r->upstream->peer.free; r->upstream->peer.data = kp; r->upstream->peer.get = ngx_http_upstream_get_keepalive_peer; r->upstream->peer.free = ngx_http_upstream_free_keepalive_peer; #if (NGX_HTTP_SSL) kp->original_set_session = r->upstream->peer.set_session; kp->original_save_session = r->upstream->peer.save_session; r->upstream->peer.set_session = ngx_http_upstream_keepalive_set_session; r->upstream->peer.save_session = ngx_http_upstream_keepalive_save_session; #endif return NGX_OK; } static ngx_int_t ngx_http_upstream_get_keepalive_peer(ngx_peer_connection_t *pc, void *data) { ngx_http_upstream_keepalive_peer_data_t *kp = data; ngx_http_upstream_keepalive_cache_t *item; ngx_int_t rc; ngx_queue_t *q, *cache; ngx_connection_t *c; ngx_log_debug0(NGX_LOG_DEBUG_HTTP, pc->log, 0, "get keepalive peer"); /* ask balancer */ rc = kp->original_get_peer(pc, kp->data); if (rc != NGX_OK) { return rc; } /* search cache for suitable connection */ cache = &kp->conf->cache; for (q = ngx_queue_head(cache); q != ngx_queue_sentinel(cache); q = ngx_queue_next(q)) { item = ngx_queue_data(q, ngx_http_upstream_keepalive_cache_t, queue); c = item->connection; if (ngx_memn2cmp((u_char *) &item->sockaddr, (u_char *) pc->sockaddr, item->socklen, pc->socklen) == 0) { ngx_queue_remove(q); ngx_queue_insert_head(&kp->conf->free, q); goto found; } } return NGX_OK; found: ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0, "get keepalive peer: using connection %p", c); c->idle = 0; c->sent = 0; c->data = NULL; c->log = pc->log; c->read->log = pc->log; c->write->log = pc->log; c->pool->log = pc->log; if (c->read->timer_set) { ngx_del_timer(c->read); } pc->connection = c; pc->cached = 1; return NGX_DONE; } static void ngx_http_upstream_free_keepalive_peer(ngx_peer_connection_t *pc, void *data, ngx_uint_t state) { ngx_http_upstream_keepalive_peer_data_t *kp = data; ngx_http_upstream_keepalive_cache_t *item; ngx_queue_t *q; ngx_connection_t *c; ngx_http_upstream_t *u; ngx_log_debug0(NGX_LOG_DEBUG_HTTP, pc->log, 0, "free keepalive peer"); /* cache valid connections */ u = kp->upstream; c = pc->connection; if (state & NGX_PEER_FAILED || c == NULL || c->read->eof || c->read->error || c->read->timedout || c->write->error || c->write->timedout) { goto invalid; } if (c->requests >= kp->conf->requests) { goto invalid; } if (ngx_current_msec - c->start_time > kp->conf->time) { goto invalid; } if (!u->keepalive) { goto invalid; } if (!u->request_body_sent) { goto invalid; } if (ngx_terminate || ngx_exiting) { goto invalid; } if (ngx_handle_read_event(c->read, 0) != NGX_OK) { goto invalid; } ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0, "free keepalive peer: saving connection %p", c); if (ngx_queue_empty(&kp->conf->free)) { q = ngx_queue_last(&kp->conf->cache); ngx_queue_remove(q); item = ngx_queue_data(q, ngx_http_upstream_keepalive_cache_t, queue); ngx_http_upstream_keepalive_close(item->connection); } else { q = ngx_queue_head(&kp->conf->free); ngx_queue_remove(q); item = ngx_queue_data(q, ngx_http_upstream_keepalive_cache_t, queue); } ngx_queue_insert_head(&kp->conf->cache, q); item->connection = c; pc->connection = NULL; c->read->delayed = 0; ngx_add_timer(c->read, kp->conf->timeout); if (c->write->timer_set) { ngx_del_timer(c->write); } c->write->handler = ngx_http_upstream_keepalive_dummy_handler; c->read->handler = ngx_http_upstream_keepalive_close_handler; c->data = item; c->idle = 1; c->log = ngx_cycle->log; c->read->log = ngx_cycle->log; c->write->log = ngx_cycle->log; c->pool->log = ngx_cycle->log; item->socklen = pc->socklen; ngx_memcpy(&item->sockaddr, pc->sockaddr, pc->socklen); if (c->read->ready) { ngx_http_upstream_keepalive_close_handler(c->read); } invalid: kp->original_free_peer(pc, kp->data, state); } static void ngx_http_upstream_keepalive_dummy_handler(ngx_event_t *ev) { ngx_log_debug0(NGX_LOG_DEBUG_HTTP, ev->log, 0, "keepalive dummy handler"); } static void ngx_http_upstream_keepalive_close_handler(ngx_event_t *ev) { ngx_http_upstream_keepalive_srv_conf_t *conf; ngx_http_upstream_keepalive_cache_t *item; int n; char buf[1]; ngx_connection_t *c; ngx_log_debug0(NGX_LOG_DEBUG_HTTP, ev->log, 0, "keepalive close handler"); c = ev->data; if (c->close || c->read->timedout) { goto close; } n = recv(c->fd, buf, 1, MSG_PEEK); if (n == -1 && ngx_socket_errno == NGX_EAGAIN) { ev->ready = 0; if (ngx_handle_read_event(c->read, 0) != NGX_OK) { goto close; } return; } close: item = c->data; conf = item->conf; ngx_http_upstream_keepalive_close(c); ngx_queue_remove(&item->queue); ngx_queue_insert_head(&conf->free, &item->queue); } static void ngx_http_upstream_keepalive_close(ngx_connection_t *c) { #if (NGX_HTTP_SSL) if (c->ssl) { c->ssl->no_wait_shutdown = 1; c->ssl->no_send_shutdown = 1; if (ngx_ssl_shutdown(c) == NGX_AGAIN) { c->ssl->handler = ngx_http_upstream_keepalive_close; return; } } #endif ngx_destroy_pool(c->pool); ngx_close_connection(c); } #if (NGX_HTTP_SSL) static ngx_int_t ngx_http_upstream_keepalive_set_session(ngx_peer_connection_t *pc, void *data) { ngx_http_upstream_keepalive_peer_data_t *kp = data; return kp->original_set_session(pc, kp->data); } static void ngx_http_upstream_keepalive_save_session(ngx_peer_connection_t *pc, void *data) { ngx_http_upstream_keepalive_peer_data_t *kp = data; kp->original_save_session(pc, kp->data); return; } #endif static void * ngx_http_upstream_keepalive_create_conf(ngx_conf_t *cf) { ngx_http_upstream_keepalive_srv_conf_t *conf; conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_upstream_keepalive_srv_conf_t)); if (conf == NULL) { return NULL; } /* * set by ngx_pcalloc(): * * conf->original_init_upstream = NULL; * conf->original_init_peer = NULL; * conf->max_cached = 0; */ conf->time = NGX_CONF_UNSET_MSEC; conf->timeout = NGX_CONF_UNSET_MSEC; conf->requests = NGX_CONF_UNSET_UINT; return conf; } static char * ngx_http_upstream_keepalive(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_upstream_srv_conf_t *uscf; ngx_http_upstream_keepalive_srv_conf_t *kcf = conf; ngx_int_t n; ngx_str_t *value; if (kcf->max_cached) { return "is duplicate"; } /* read options */ value = cf->args->elts; n = ngx_atoi(value[1].data, value[1].len); if (n == NGX_ERROR || n == 0) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid value \"%V\" in \"%V\" directive", &value[1], &cmd->name); return NGX_CONF_ERROR; } kcf->max_cached = n; /* init upstream handler */ uscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_upstream_module); kcf->original_init_upstream = uscf->peer.init_upstream ? uscf->peer.init_upstream : ngx_http_upstream_init_round_robin; uscf->peer.init_upstream = ngx_http_upstream_init_keepalive; return NGX_CONF_OK; }