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view src/http/ngx_http_upstream_round_robin.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 e38e9c50a40e
children 90cc7194e993
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_HTTP_UPSTREAM_ROUND_ROBIN_H_INCLUDED_
#define _NGX_HTTP_UPSTREAM_ROUND_ROBIN_H_INCLUDED_


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


typedef struct ngx_http_upstream_rr_peer_s   ngx_http_upstream_rr_peer_t;

struct ngx_http_upstream_rr_peer_s {
    struct sockaddr                *sockaddr;
    socklen_t                       socklen;
    ngx_str_t                       name;
    ngx_str_t                       server;

    ngx_int_t                       current_weight;
    ngx_int_t                       effective_weight;
    ngx_int_t                       weight;

    ngx_uint_t                      conns;
    ngx_uint_t                      max_conns;

    ngx_uint_t                      fails;
    time_t                          accessed;
    time_t                          checked;

    ngx_uint_t                      max_fails;
    time_t                          fail_timeout;
    ngx_msec_t                      slow_start;
    ngx_msec_t                      start_time;

    ngx_uint_t                      down;

#if (NGX_HTTP_SSL || NGX_COMPAT)
    void                           *ssl_session;
    int                             ssl_session_len;
#endif

#if (NGX_HTTP_UPSTREAM_ZONE)
    ngx_atomic_t                    lock;
#endif

    ngx_http_upstream_rr_peer_t    *next;

    NGX_COMPAT_BEGIN(32)
    NGX_COMPAT_END
};


typedef struct ngx_http_upstream_rr_peers_s  ngx_http_upstream_rr_peers_t;

struct ngx_http_upstream_rr_peers_s {
    ngx_uint_t                      number;

#if (NGX_HTTP_UPSTREAM_ZONE)
    ngx_slab_pool_t                *shpool;
    ngx_atomic_t                    rwlock;
    ngx_http_upstream_rr_peers_t   *zone_next;
#endif

    ngx_uint_t                      total_weight;

    unsigned                        single:1;
    unsigned                        weighted:1;

    ngx_str_t                      *name;

    ngx_http_upstream_rr_peers_t   *next;

    ngx_http_upstream_rr_peer_t    *peer;
};


#if (NGX_HTTP_UPSTREAM_ZONE)

#define ngx_http_upstream_rr_peers_rlock(peers)                               \
                                                                              \
    if (peers->shpool) {                                                      \
        ngx_rwlock_rlock(&peers->rwlock);                                     \
    }

#define ngx_http_upstream_rr_peers_wlock(peers)                               \
                                                                              \
    if (peers->shpool) {                                                      \
        ngx_rwlock_wlock(&peers->rwlock);                                     \
    }

#define ngx_http_upstream_rr_peers_unlock(peers)                              \
                                                                              \
    if (peers->shpool) {                                                      \
        ngx_rwlock_unlock(&peers->rwlock);                                    \
    }


#define ngx_http_upstream_rr_peer_lock(peers, peer)                           \
                                                                              \
    if (peers->shpool) {                                                      \
        ngx_rwlock_wlock(&peer->lock);                                        \
    }

#define ngx_http_upstream_rr_peer_unlock(peers, peer)                         \
                                                                              \
    if (peers->shpool) {                                                      \
        ngx_rwlock_unlock(&peer->lock);                                       \
    }

#else

#define ngx_http_upstream_rr_peers_rlock(peers)
#define ngx_http_upstream_rr_peers_wlock(peers)
#define ngx_http_upstream_rr_peers_unlock(peers)
#define ngx_http_upstream_rr_peer_lock(peers, peer)
#define ngx_http_upstream_rr_peer_unlock(peers, peer)

#endif


typedef struct {
    ngx_uint_t                      config;
    ngx_http_upstream_rr_peers_t   *peers;
    ngx_http_upstream_rr_peer_t    *current;
    uintptr_t                      *tried;
    uintptr_t                       data;
} ngx_http_upstream_rr_peer_data_t;


ngx_int_t ngx_http_upstream_init_round_robin(ngx_conf_t *cf,
    ngx_http_upstream_srv_conf_t *us);
ngx_int_t ngx_http_upstream_init_round_robin_peer(ngx_http_request_t *r,
    ngx_http_upstream_srv_conf_t *us);
ngx_int_t ngx_http_upstream_create_round_robin_peer(ngx_http_request_t *r,
    ngx_http_upstream_resolved_t *ur);
ngx_int_t ngx_http_upstream_get_round_robin_peer(ngx_peer_connection_t *pc,
    void *data);
void ngx_http_upstream_free_round_robin_peer(ngx_peer_connection_t *pc,
    void *data, ngx_uint_t state);

#if (NGX_HTTP_SSL)
ngx_int_t
    ngx_http_upstream_set_round_robin_peer_session(ngx_peer_connection_t *pc,
    void *data);
void ngx_http_upstream_save_round_robin_peer_session(ngx_peer_connection_t *pc,
    void *data);
#endif


#endif /* _NGX_HTTP_UPSTREAM_ROUND_ROBIN_H_INCLUDED_ */