Mercurial > hg > nginx
view src/event/ngx_event_timer.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 | 3efdd7788bb0 |
children | 3069dd358ba2 |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> ngx_rbtree_t ngx_event_timer_rbtree; static ngx_rbtree_node_t ngx_event_timer_sentinel; /* * the event timer rbtree may contain the duplicate keys, however, * it should not be a problem, because we use the rbtree to find * a minimum timer value only */ ngx_int_t ngx_event_timer_init(ngx_log_t *log) { ngx_rbtree_init(&ngx_event_timer_rbtree, &ngx_event_timer_sentinel, ngx_rbtree_insert_timer_value); return NGX_OK; } ngx_msec_t ngx_event_find_timer(void) { ngx_msec_int_t timer; ngx_rbtree_node_t *node, *root, *sentinel; if (ngx_event_timer_rbtree.root == &ngx_event_timer_sentinel) { return NGX_TIMER_INFINITE; } root = ngx_event_timer_rbtree.root; sentinel = ngx_event_timer_rbtree.sentinel; node = ngx_rbtree_min(root, sentinel); timer = (ngx_msec_int_t) (node->key - ngx_current_msec); return (ngx_msec_t) (timer > 0 ? timer : 0); } void ngx_event_expire_timers(void) { ngx_event_t *ev; ngx_rbtree_node_t *node, *root, *sentinel; sentinel = ngx_event_timer_rbtree.sentinel; for ( ;; ) { root = ngx_event_timer_rbtree.root; if (root == sentinel) { return; } node = ngx_rbtree_min(root, sentinel); /* node->key > ngx_current_time */ if ((ngx_msec_int_t) (node->key - ngx_current_msec) > 0) { return; } ev = (ngx_event_t *) ((char *) node - offsetof(ngx_event_t, timer)); ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0, "event timer del: %d: %M", ngx_event_ident(ev->data), ev->timer.key); ngx_rbtree_delete(&ngx_event_timer_rbtree, &ev->timer); #if (NGX_DEBUG) ev->timer.left = NULL; ev->timer.right = NULL; ev->timer.parent = NULL; #endif ev->timer_set = 0; ev->timedout = 1; ev->handler(ev); } } void ngx_event_cancel_timers(void) { ngx_event_t *ev; ngx_rbtree_node_t *node, *root, *sentinel; sentinel = ngx_event_timer_rbtree.sentinel; for ( ;; ) { root = ngx_event_timer_rbtree.root; if (root == sentinel) { return; } node = ngx_rbtree_min(root, sentinel); ev = (ngx_event_t *) ((char *) node - offsetof(ngx_event_t, timer)); if (!ev->cancelable) { return; } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0, "event timer cancel: %d: %M", ngx_event_ident(ev->data), ev->timer.key); ngx_rbtree_delete(&ngx_event_timer_rbtree, &ev->timer); #if (NGX_DEBUG) ev->timer.left = NULL; ev->timer.right = NULL; ev->timer.parent = NULL; #endif ev->timer_set = 0; ev->handler(ev); } }