Mercurial > hg > nginx
view src/stream/ngx_stream_upstream_zone_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 | 8ed51b02f655 |
children | 1eb753aa8e5e |
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/* * Copyright (C) Ruslan Ermilov * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_stream.h> static char *ngx_stream_upstream_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_int_t ngx_stream_upstream_init_zone(ngx_shm_zone_t *shm_zone, void *data); static ngx_stream_upstream_rr_peers_t *ngx_stream_upstream_zone_copy_peers( ngx_slab_pool_t *shpool, ngx_stream_upstream_srv_conf_t *uscf); static ngx_command_t ngx_stream_upstream_zone_commands[] = { { ngx_string("zone"), NGX_STREAM_UPS_CONF|NGX_CONF_TAKE12, ngx_stream_upstream_zone, 0, 0, NULL }, ngx_null_command }; static ngx_stream_module_t ngx_stream_upstream_zone_module_ctx = { NULL, /* preconfiguration */ NULL, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL /* merge server configuration */ }; ngx_module_t ngx_stream_upstream_zone_module = { NGX_MODULE_V1, &ngx_stream_upstream_zone_module_ctx, /* module context */ ngx_stream_upstream_zone_commands, /* module directives */ NGX_STREAM_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 char * ngx_stream_upstream_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ssize_t size; ngx_str_t *value; ngx_stream_upstream_srv_conf_t *uscf; ngx_stream_upstream_main_conf_t *umcf; uscf = ngx_stream_conf_get_module_srv_conf(cf, ngx_stream_upstream_module); umcf = ngx_stream_conf_get_module_main_conf(cf, ngx_stream_upstream_module); value = cf->args->elts; if (!value[1].len) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid zone name \"%V\"", &value[1]); return NGX_CONF_ERROR; } if (cf->args->nelts == 3) { size = ngx_parse_size(&value[2]); if (size == NGX_ERROR) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid zone size \"%V\"", &value[2]); return NGX_CONF_ERROR; } if (size < (ssize_t) (8 * ngx_pagesize)) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "zone \"%V\" is too small", &value[1]); return NGX_CONF_ERROR; } } else { size = 0; } uscf->shm_zone = ngx_shared_memory_add(cf, &value[1], size, &ngx_stream_upstream_module); if (uscf->shm_zone == NULL) { return NGX_CONF_ERROR; } uscf->shm_zone->init = ngx_stream_upstream_init_zone; uscf->shm_zone->data = umcf; uscf->shm_zone->noreuse = 1; return NGX_CONF_OK; } static ngx_int_t ngx_stream_upstream_init_zone(ngx_shm_zone_t *shm_zone, void *data) { size_t len; ngx_uint_t i; ngx_slab_pool_t *shpool; ngx_stream_upstream_rr_peers_t *peers, **peersp; ngx_stream_upstream_srv_conf_t *uscf, **uscfp; ngx_stream_upstream_main_conf_t *umcf; shpool = (ngx_slab_pool_t *) shm_zone->shm.addr; umcf = shm_zone->data; uscfp = umcf->upstreams.elts; if (shm_zone->shm.exists) { peers = shpool->data; for (i = 0; i < umcf->upstreams.nelts; i++) { uscf = uscfp[i]; if (uscf->shm_zone != shm_zone) { continue; } uscf->peer.data = peers; peers = peers->zone_next; } return NGX_OK; } len = sizeof(" in upstream zone \"\"") + shm_zone->shm.name.len; shpool->log_ctx = ngx_slab_alloc(shpool, len); if (shpool->log_ctx == NULL) { return NGX_ERROR; } ngx_sprintf(shpool->log_ctx, " in upstream zone \"%V\"%Z", &shm_zone->shm.name); /* copy peers to shared memory */ peersp = (ngx_stream_upstream_rr_peers_t **) (void *) &shpool->data; for (i = 0; i < umcf->upstreams.nelts; i++) { uscf = uscfp[i]; if (uscf->shm_zone != shm_zone) { continue; } peers = ngx_stream_upstream_zone_copy_peers(shpool, uscf); if (peers == NULL) { return NGX_ERROR; } *peersp = peers; peersp = &peers->zone_next; } return NGX_OK; } static ngx_stream_upstream_rr_peers_t * ngx_stream_upstream_zone_copy_peers(ngx_slab_pool_t *shpool, ngx_stream_upstream_srv_conf_t *uscf) { ngx_stream_upstream_rr_peer_t *peer, **peerp; ngx_stream_upstream_rr_peers_t *peers, *backup; peers = ngx_slab_alloc(shpool, sizeof(ngx_stream_upstream_rr_peers_t)); if (peers == NULL) { return NULL; } ngx_memcpy(peers, uscf->peer.data, sizeof(ngx_stream_upstream_rr_peers_t)); peers->shpool = shpool; for (peerp = &peers->peer; *peerp; peerp = &peer->next) { /* pool is unlocked */ peer = ngx_slab_calloc_locked(shpool, sizeof(ngx_stream_upstream_rr_peer_t)); if (peer == NULL) { return NULL; } ngx_memcpy(peer, *peerp, sizeof(ngx_stream_upstream_rr_peer_t)); *peerp = peer; } if (peers->next == NULL) { goto done; } backup = ngx_slab_alloc(shpool, sizeof(ngx_stream_upstream_rr_peers_t)); if (backup == NULL) { return NULL; } ngx_memcpy(backup, peers->next, sizeof(ngx_stream_upstream_rr_peers_t)); backup->shpool = shpool; for (peerp = &backup->peer; *peerp; peerp = &peer->next) { /* pool is unlocked */ peer = ngx_slab_calloc_locked(shpool, sizeof(ngx_stream_upstream_rr_peer_t)); if (peer == NULL) { return NULL; } ngx_memcpy(peer, *peerp, sizeof(ngx_stream_upstream_rr_peer_t)); *peerp = peer; } peers->next = backup; done: uscf->peer.data = peers; return peers; }