view src/event/ngx_event_connect.h @ 7969:84c60a3cd12a stable-1.20

Changed ngx_chain_update_chains() to test tag first (ticket #2248). Without this change, aio used with HTTP/2 can result in connection hang, as observed with "aio threads; aio_write on;" and proxying (ticket #2248). The problem is that HTTP/2 updates buffers outside of the output filters (notably, marks them as sent), and then posts a write event to call output filters. If a filter does not call the next one for some reason (for example, because of an AIO operation in progress), this might result in a state when the owner of a buffer already called ngx_chain_update_chains() and can reuse the buffer, while the same buffer is still sitting in the busy chain of some other filter. In the particular case a buffer was sitting in output chain's ctx->busy, and was reused by event pipe. Output chain's ctx->busy was permanently blocked by it, and this resulted in connection hang. Fix is to change ngx_chain_update_chains() to skip buffers from other modules unconditionally, without trying to wait for these buffers to become empty.
author Maxim Dounin <mdounin@mdounin.ru>
date Sat, 30 Oct 2021 02:39:19 +0300
parents 570d8c626eea
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_EVENT_CONNECT_H_INCLUDED_
#define _NGX_EVENT_CONNECT_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>


#define NGX_PEER_KEEPALIVE           1
#define NGX_PEER_NEXT                2
#define NGX_PEER_FAILED              4


typedef struct ngx_peer_connection_s  ngx_peer_connection_t;

typedef ngx_int_t (*ngx_event_get_peer_pt)(ngx_peer_connection_t *pc,
    void *data);
typedef void (*ngx_event_free_peer_pt)(ngx_peer_connection_t *pc, void *data,
    ngx_uint_t state);
typedef void (*ngx_event_notify_peer_pt)(ngx_peer_connection_t *pc,
    void *data, ngx_uint_t type);
typedef ngx_int_t (*ngx_event_set_peer_session_pt)(ngx_peer_connection_t *pc,
    void *data);
typedef void (*ngx_event_save_peer_session_pt)(ngx_peer_connection_t *pc,
    void *data);


struct ngx_peer_connection_s {
    ngx_connection_t                *connection;

    struct sockaddr                 *sockaddr;
    socklen_t                        socklen;
    ngx_str_t                       *name;

    ngx_uint_t                       tries;
    ngx_msec_t                       start_time;

    ngx_event_get_peer_pt            get;
    ngx_event_free_peer_pt           free;
    ngx_event_notify_peer_pt         notify;
    void                            *data;

#if (NGX_SSL || NGX_COMPAT)
    ngx_event_set_peer_session_pt    set_session;
    ngx_event_save_peer_session_pt   save_session;
#endif

    ngx_addr_t                      *local;

    int                              type;
    int                              rcvbuf;

    ngx_log_t                       *log;

    unsigned                         cached:1;
    unsigned                         transparent:1;
    unsigned                         so_keepalive:1;
    unsigned                         down:1;

                                     /* ngx_connection_log_error_e */
    unsigned                         log_error:2;

    NGX_COMPAT_BEGIN(2)
    NGX_COMPAT_END
};


ngx_int_t ngx_event_connect_peer(ngx_peer_connection_t *pc);
ngx_int_t ngx_event_get_peer(ngx_peer_connection_t *pc, void *data);


#endif /* _NGX_EVENT_CONNECT_H_INCLUDED_ */