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view src/stream/ngx_stream_upstream.h @ 6806:75dbab4ea930

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Events: improved error event handling for UDP sockets. Normally, the epoll module calls the read and write handlers depending on whether EPOLLIN and EPOLLOUT are reported by epoll_wait(). No error processing is done in the module, the handlers are expected to get an error when doing I/O. If an error event is reported without EPOLLIN and EPOLLOUT, the module set both EPOLLIN and EPOLLOUT to ensure the error event is handled at least in one active handler. This works well unless the error is delivered along with only one of EPOLLIN or EPOLLOUT, and the corresponding handler does not do any I/O. For example, it happened when getting EPOLLERR|EPOLLOUT from epoll_wait() upon receiving "ICMP port unreachable" while proxying UDP. As the write handler had nothing to send it was not able to detect and log an error, and did not switch to the next upstream. The fix is to unconditionally set EPOLLIN and EPOLLOUT in case of an error event. In the aforementioned case, this causes the read handler to be called which does recv() and detects an error. In addition to the epoll module, analogous changes were made in devpoll/eventport/poll.
author Dmitry Volyntsev <xeioex@nginx.com>
date Mon, 21 Nov 2016 16:03:42 +0300
parents d1d0dd69a419
children 54cf51c4f07a
line wrap: on
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_STREAM_UPSTREAM_H_INCLUDED_
#define _NGX_STREAM_UPSTREAM_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_stream.h>
#include <ngx_event_connect.h>


#define NGX_STREAM_UPSTREAM_CREATE        0x0001
#define NGX_STREAM_UPSTREAM_WEIGHT        0x0002
#define NGX_STREAM_UPSTREAM_MAX_FAILS     0x0004
#define NGX_STREAM_UPSTREAM_FAIL_TIMEOUT  0x0008
#define NGX_STREAM_UPSTREAM_DOWN          0x0010
#define NGX_STREAM_UPSTREAM_BACKUP        0x0020
#define NGX_STREAM_UPSTREAM_MAX_CONNS     0x0100


typedef struct {
    ngx_array_t                        upstreams;
                                           /* ngx_stream_upstream_srv_conf_t */
} ngx_stream_upstream_main_conf_t;


typedef struct ngx_stream_upstream_srv_conf_s  ngx_stream_upstream_srv_conf_t;


typedef ngx_int_t (*ngx_stream_upstream_init_pt)(ngx_conf_t *cf,
    ngx_stream_upstream_srv_conf_t *us);
typedef ngx_int_t (*ngx_stream_upstream_init_peer_pt)(ngx_stream_session_t *s,
    ngx_stream_upstream_srv_conf_t *us);


typedef struct {
    ngx_stream_upstream_init_pt        init_upstream;
    ngx_stream_upstream_init_peer_pt   init;
    void                              *data;
} ngx_stream_upstream_peer_t;


typedef struct {
    ngx_str_t                          name;
    ngx_addr_t                        *addrs;
    ngx_uint_t                         naddrs;
    ngx_uint_t                         weight;
    ngx_uint_t                         max_conns;
    ngx_uint_t                         max_fails;
    time_t                             fail_timeout;
    ngx_msec_t                         slow_start;

    unsigned                           down:1;
    unsigned                           backup:1;

    NGX_COMPAT_BEGIN(4)
    NGX_COMPAT_END
} ngx_stream_upstream_server_t;


struct ngx_stream_upstream_srv_conf_s {
    ngx_stream_upstream_peer_t         peer;
    void                             **srv_conf;

    ngx_array_t                       *servers;
                                              /* ngx_stream_upstream_server_t */

    ngx_uint_t                         flags;
    ngx_str_t                          host;
    u_char                            *file_name;
    ngx_uint_t                         line;
    in_port_t                          port;
    ngx_uint_t                         no_port;  /* unsigned no_port:1 */

#if (NGX_STREAM_UPSTREAM_ZONE)
    ngx_shm_zone_t                    *shm_zone;
#endif
};


typedef struct {
    ngx_msec_t                         response_time;
    ngx_msec_t                         connect_time;
    ngx_msec_t                         first_byte_time;
    off_t                              bytes_sent;
    off_t                              bytes_received;

    ngx_str_t                         *peer;
} ngx_stream_upstream_state_t;


typedef struct {
    ngx_str_t                          host;
    in_port_t                          port;
    ngx_uint_t                         no_port; /* unsigned no_port:1 */

    ngx_uint_t                         naddrs;
    ngx_resolver_addr_t               *addrs;

    struct sockaddr                   *sockaddr;
    socklen_t                          socklen;
    ngx_str_t                          name;

    ngx_resolver_ctx_t                *ctx;
} ngx_stream_upstream_resolved_t;


typedef struct {
    ngx_peer_connection_t              peer;

    ngx_buf_t                          downstream_buf;
    ngx_buf_t                          upstream_buf;

    ngx_chain_t                       *free;
    ngx_chain_t                       *upstream_out;
    ngx_chain_t                       *upstream_busy;
    ngx_chain_t                       *downstream_out;
    ngx_chain_t                       *downstream_busy;

    off_t                              received;
    time_t                             start_sec;
    ngx_uint_t                         responses;

    ngx_str_t                          ssl_name;

    ngx_stream_upstream_srv_conf_t    *upstream;
    ngx_stream_upstream_resolved_t    *resolved;
    ngx_stream_upstream_state_t       *state;
    unsigned                           connected:1;
    unsigned                           proxy_protocol:1;
} ngx_stream_upstream_t;


ngx_stream_upstream_srv_conf_t *ngx_stream_upstream_add(ngx_conf_t *cf,
    ngx_url_t *u, ngx_uint_t flags);


#define ngx_stream_conf_upstream_srv_conf(uscf, module)                       \
    uscf->srv_conf[module.ctx_index]


extern ngx_module_t  ngx_stream_upstream_module;


#endif /* _NGX_STREAM_UPSTREAM_H_INCLUDED_ */