Mercurial > hg > nginx
view auto/cc/ccc @ 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 | d620f497c50f |
children |
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# Copyright (C) Igor Sysoev # Copyright (C) Nginx, Inc. # Compaq C V6.5-207 ngx_include_opt="-I" # warnings CFLAGS="$CFLAGS -msg_enable level6 -msg_fatal level6" CFLAGS="$CFLAGS -msg_disable unknownmacro" CFLAGS="$CFLAGS -msg_disable unusedincl" CFLAGS="$CFLAGS -msg_disable unnecincl" CFLAGS="$CFLAGS -msg_disable nestincl" CFLAGS="$CFLAGS -msg_disable strctpadding" CFLAGS="$CFLAGS -msg_disable ansialiascast" CFLAGS="$CFLAGS -msg_disable inlinestoclsmod" CFLAGS="$CFLAGS -msg_disable cxxkeyword" CFLAGS="$CFLAGS -msg_disable longlongsufx" CFLAGS="$CFLAGS -msg_disable valuepres" # STUB CFLAGS="$CFLAGS -msg_disable truncintcast" CFLAGS="$CFLAGS -msg_disable trunclongcast" CFLAGS="$CFLAGS -msg_disable truncintasn" CFLAGS="$CFLAGS -msg_disable trunclongint" CFLAGS="$CFLAGS -msg_disable intconcastsgn" CFLAGS="$CFLAGS -msg_disable intconstsign" CFLAGS="$CFLAGS -msg_disable switchlong" CFLAGS="$CFLAGS -msg_disable subscrbounds2" CFLAGS="$CFLAGS -msg_disable hexoctunsign" CFLAGS="$CFLAGS -msg_disable ignorecallval" CFLAGS="$CFLAGS -msg_disable nonstandcast" CFLAGS="$CFLAGS -msg_disable embedcomment" CFLAGS="$CFLAGS -msg_disable unreachcode" CFLAGS="$CFLAGS -msg_disable questcompare2" CFLAGS="$CFLAGS -msg_disable unusedtop" CFLAGS="$CFLAGS -msg_disable unrefdecl" CFLAGS="$CFLAGS -msg_disable bitnotint"