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view src/event/ngx_event_pipe.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 adc2414856b1
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_EVENT_PIPE_H_INCLUDED_
#define _NGX_EVENT_PIPE_H_INCLUDED_


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


typedef struct ngx_event_pipe_s  ngx_event_pipe_t;

typedef ngx_int_t (*ngx_event_pipe_input_filter_pt)(ngx_event_pipe_t *p,
                                                    ngx_buf_t *buf);
typedef ngx_int_t (*ngx_event_pipe_output_filter_pt)(void *data,
                                                     ngx_chain_t *chain);


struct ngx_event_pipe_s {
    ngx_connection_t  *upstream;
    ngx_connection_t  *downstream;

    ngx_chain_t       *free_raw_bufs;
    ngx_chain_t       *in;
    ngx_chain_t      **last_in;

    ngx_chain_t       *writing;

    ngx_chain_t       *out;
    ngx_chain_t       *free;
    ngx_chain_t       *busy;

    /*
     * the input filter i.e. that moves HTTP/1.1 chunks
     * from the raw bufs to an incoming chain
     */

    ngx_event_pipe_input_filter_pt    input_filter;
    void                             *input_ctx;

    ngx_event_pipe_output_filter_pt   output_filter;
    void                             *output_ctx;

#if (NGX_THREADS || NGX_COMPAT)
    ngx_int_t                       (*thread_handler)(ngx_thread_task_t *task,
                                                      ngx_file_t *file);
    void                             *thread_ctx;
    ngx_thread_task_t                *thread_task;
#endif

    unsigned           read:1;
    unsigned           cacheable:1;
    unsigned           single_buf:1;
    unsigned           free_bufs:1;
    unsigned           upstream_done:1;
    unsigned           upstream_error:1;
    unsigned           upstream_eof:1;
    unsigned           upstream_blocked:1;
    unsigned           downstream_done:1;
    unsigned           downstream_error:1;
    unsigned           cyclic_temp_file:1;
    unsigned           aio:1;

    ngx_int_t          allocated;
    ngx_bufs_t         bufs;
    ngx_buf_tag_t      tag;

    ssize_t            busy_size;

    off_t              read_length;
    off_t              length;

    off_t              max_temp_file_size;
    ssize_t            temp_file_write_size;

    ngx_msec_t         read_timeout;
    ngx_msec_t         send_timeout;
    ssize_t            send_lowat;

    ngx_pool_t        *pool;
    ngx_log_t         *log;

    ngx_chain_t       *preread_bufs;
    size_t             preread_size;
    ngx_buf_t         *buf_to_file;

    size_t             limit_rate;
    time_t             start_sec;

    ngx_temp_file_t   *temp_file;

    /* STUB */ int     num;
};


ngx_int_t ngx_event_pipe(ngx_event_pipe_t *p, ngx_int_t do_write);
ngx_int_t ngx_event_pipe_copy_input_filter(ngx_event_pipe_t *p, ngx_buf_t *buf);
ngx_int_t ngx_event_pipe_add_free_buf(ngx_event_pipe_t *p, ngx_buf_t *b);


#endif /* _NGX_EVENT_PIPE_H_INCLUDED_ */