Mercurial > hg > nginx
view src/http/ngx_http_copy_filter_module.c @ 6806:75dbab4ea930
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 | c5f81dcf97a7 |
children | ce37362a7a70 |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef struct { ngx_bufs_t bufs; } ngx_http_copy_filter_conf_t; #if (NGX_HAVE_FILE_AIO) static void ngx_http_copy_aio_handler(ngx_output_chain_ctx_t *ctx, ngx_file_t *file); static void ngx_http_copy_aio_event_handler(ngx_event_t *ev); #if (NGX_HAVE_AIO_SENDFILE) static ssize_t ngx_http_copy_aio_sendfile_preload(ngx_buf_t *file); static void ngx_http_copy_aio_sendfile_event_handler(ngx_event_t *ev); #endif #endif #if (NGX_THREADS) static ngx_int_t ngx_http_copy_thread_handler(ngx_thread_task_t *task, ngx_file_t *file); static void ngx_http_copy_thread_event_handler(ngx_event_t *ev); #endif static void *ngx_http_copy_filter_create_conf(ngx_conf_t *cf); static char *ngx_http_copy_filter_merge_conf(ngx_conf_t *cf, void *parent, void *child); static ngx_int_t ngx_http_copy_filter_init(ngx_conf_t *cf); static ngx_command_t ngx_http_copy_filter_commands[] = { { ngx_string("output_buffers"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2, ngx_conf_set_bufs_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_copy_filter_conf_t, bufs), NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_copy_filter_module_ctx = { NULL, /* preconfiguration */ ngx_http_copy_filter_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_copy_filter_create_conf, /* create location configuration */ ngx_http_copy_filter_merge_conf /* merge location configuration */ }; ngx_module_t ngx_http_copy_filter_module = { NGX_MODULE_V1, &ngx_http_copy_filter_module_ctx, /* module context */ ngx_http_copy_filter_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_http_output_body_filter_pt ngx_http_next_body_filter; static ngx_int_t ngx_http_copy_filter(ngx_http_request_t *r, ngx_chain_t *in) { ngx_int_t rc; ngx_connection_t *c; ngx_output_chain_ctx_t *ctx; ngx_http_core_loc_conf_t *clcf; ngx_http_copy_filter_conf_t *conf; c = r->connection; ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0, "http copy filter: \"%V?%V\"", &r->uri, &r->args); ctx = ngx_http_get_module_ctx(r, ngx_http_copy_filter_module); if (ctx == NULL) { ctx = ngx_pcalloc(r->pool, sizeof(ngx_output_chain_ctx_t)); if (ctx == NULL) { return NGX_ERROR; } ngx_http_set_ctx(r, ctx, ngx_http_copy_filter_module); conf = ngx_http_get_module_loc_conf(r, ngx_http_copy_filter_module); clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module); ctx->sendfile = c->sendfile; ctx->need_in_memory = r->main_filter_need_in_memory || r->filter_need_in_memory; ctx->need_in_temp = r->filter_need_temporary; ctx->alignment = clcf->directio_alignment; ctx->pool = r->pool; ctx->bufs = conf->bufs; ctx->tag = (ngx_buf_tag_t) &ngx_http_copy_filter_module; ctx->output_filter = (ngx_output_chain_filter_pt) ngx_http_next_body_filter; ctx->filter_ctx = r; #if (NGX_HAVE_FILE_AIO) if (ngx_file_aio && clcf->aio == NGX_HTTP_AIO_ON) { ctx->aio_handler = ngx_http_copy_aio_handler; #if (NGX_HAVE_AIO_SENDFILE) ctx->aio_preload = ngx_http_copy_aio_sendfile_preload; #endif } #endif #if (NGX_THREADS) if (clcf->aio == NGX_HTTP_AIO_THREADS) { ctx->thread_handler = ngx_http_copy_thread_handler; } #endif if (in && in->buf && ngx_buf_size(in->buf)) { r->request_output = 1; } } #if (NGX_HAVE_FILE_AIO || NGX_THREADS) ctx->aio = r->aio; #endif rc = ngx_output_chain(ctx, in); if (ctx->in == NULL) { r->buffered &= ~NGX_HTTP_COPY_BUFFERED; } else { r->buffered |= NGX_HTTP_COPY_BUFFERED; } ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0, "http copy filter: %i \"%V?%V\"", rc, &r->uri, &r->args); return rc; } #if (NGX_HAVE_FILE_AIO) static void ngx_http_copy_aio_handler(ngx_output_chain_ctx_t *ctx, ngx_file_t *file) { ngx_http_request_t *r; r = ctx->filter_ctx; file->aio->data = r; file->aio->handler = ngx_http_copy_aio_event_handler; r->main->blocked++; r->aio = 1; ctx->aio = 1; } static void ngx_http_copy_aio_event_handler(ngx_event_t *ev) { ngx_event_aio_t *aio; ngx_http_request_t *r; aio = ev->data; r = aio->data; r->main->blocked--; r->aio = 0; r->connection->write->handler(r->connection->write); } #if (NGX_HAVE_AIO_SENDFILE) static ssize_t ngx_http_copy_aio_sendfile_preload(ngx_buf_t *file) { ssize_t n; static u_char buf[1]; ngx_event_aio_t *aio; ngx_http_request_t *r; ngx_output_chain_ctx_t *ctx; n = ngx_file_aio_read(file->file, buf, 1, file->file_pos, NULL); if (n == NGX_AGAIN) { aio = file->file->aio; aio->handler = ngx_http_copy_aio_sendfile_event_handler; r = aio->data; r->main->blocked++; r->aio = 1; ctx = ngx_http_get_module_ctx(r, ngx_http_copy_filter_module); ctx->aio = 1; } return n; } static void ngx_http_copy_aio_sendfile_event_handler(ngx_event_t *ev) { ngx_event_aio_t *aio; ngx_http_request_t *r; aio = ev->data; r = aio->data; r->main->blocked--; r->aio = 0; ev->complete = 0; r->connection->write->handler(r->connection->write); } #endif #endif #if (NGX_THREADS) static ngx_int_t ngx_http_copy_thread_handler(ngx_thread_task_t *task, ngx_file_t *file) { ngx_str_t name; ngx_thread_pool_t *tp; ngx_http_request_t *r; ngx_output_chain_ctx_t *ctx; ngx_http_core_loc_conf_t *clcf; r = file->thread_ctx; clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module); tp = clcf->thread_pool; if (tp == NULL) { if (ngx_http_complex_value(r, clcf->thread_pool_value, &name) != NGX_OK) { return NGX_ERROR; } tp = ngx_thread_pool_get((ngx_cycle_t *) ngx_cycle, &name); if (tp == NULL) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "thread pool \"%V\" not found", &name); return NGX_ERROR; } } task->event.data = r; task->event.handler = ngx_http_copy_thread_event_handler; if (ngx_thread_task_post(tp, task) != NGX_OK) { return NGX_ERROR; } r->main->blocked++; r->aio = 1; ctx = ngx_http_get_module_ctx(r, ngx_http_copy_filter_module); ctx->aio = 1; return NGX_OK; } static void ngx_http_copy_thread_event_handler(ngx_event_t *ev) { ngx_http_request_t *r; r = ev->data; r->main->blocked--; r->aio = 0; r->connection->write->handler(r->connection->write); } #endif static void * ngx_http_copy_filter_create_conf(ngx_conf_t *cf) { ngx_http_copy_filter_conf_t *conf; conf = ngx_palloc(cf->pool, sizeof(ngx_http_copy_filter_conf_t)); if (conf == NULL) { return NULL; } conf->bufs.num = 0; return conf; } static char * ngx_http_copy_filter_merge_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_copy_filter_conf_t *prev = parent; ngx_http_copy_filter_conf_t *conf = child; ngx_conf_merge_bufs_value(conf->bufs, prev->bufs, 2, 32768); return NULL; } static ngx_int_t ngx_http_copy_filter_init(ngx_conf_t *cf) { ngx_http_next_body_filter = ngx_http_top_body_filter; ngx_http_top_body_filter = ngx_http_copy_filter; return NGX_OK; }