Mercurial > hg > nginx
view src/event/modules/ngx_select_module.c @ 6847:d72b38376092
Resolver: fixed handling of partially resolved SRV.
The resolver handles SRV requests in two stages. In the first
stage it gets all SRV RRs, and in the second stage it resolves
the names from SRV RRs into addresses.
Previously, if a response to an SRV request was cached, the
queries to resolve names were not limited by a timeout. If a
response to any of these queries was not received, the SRV
request could never complete.
If a response to an SRV request was not cached, and some of the
queries to resolve names timed out, NGX_RESOLVE_TIMEDOUT was
returned instead of successfully resolved addresses.
To fix both issues, resolving of names is now always limited by
a timeout.
author | Dmitry Volyntsev <xeioex@nginx.com> |
---|---|
date | Fri, 16 Dec 2016 18:21:55 +0300 |
parents | 8c79c506ea20 |
children | a72886067bbb |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> static ngx_int_t ngx_select_init(ngx_cycle_t *cycle, ngx_msec_t timer); static void ngx_select_done(ngx_cycle_t *cycle); static ngx_int_t ngx_select_add_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags); static ngx_int_t ngx_select_del_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags); static ngx_int_t ngx_select_process_events(ngx_cycle_t *cycle, ngx_msec_t timer, ngx_uint_t flags); static void ngx_select_repair_fd_sets(ngx_cycle_t *cycle); static char *ngx_select_init_conf(ngx_cycle_t *cycle, void *conf); static fd_set master_read_fd_set; static fd_set master_write_fd_set; static fd_set work_read_fd_set; static fd_set work_write_fd_set; static ngx_int_t max_fd; static ngx_uint_t nevents; static ngx_event_t **event_index; static ngx_str_t select_name = ngx_string("select"); ngx_event_module_t ngx_select_module_ctx = { &select_name, NULL, /* create configuration */ ngx_select_init_conf, /* init configuration */ { ngx_select_add_event, /* add an event */ ngx_select_del_event, /* delete an event */ ngx_select_add_event, /* enable an event */ ngx_select_del_event, /* disable an event */ NULL, /* add an connection */ NULL, /* delete an connection */ NULL, /* trigger a notify */ ngx_select_process_events, /* process the events */ ngx_select_init, /* init the events */ ngx_select_done /* done the events */ } }; ngx_module_t ngx_select_module = { NGX_MODULE_V1, &ngx_select_module_ctx, /* module context */ NULL, /* module directives */ NGX_EVENT_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_int_t ngx_select_init(ngx_cycle_t *cycle, ngx_msec_t timer) { ngx_event_t **index; if (event_index == NULL) { FD_ZERO(&master_read_fd_set); FD_ZERO(&master_write_fd_set); nevents = 0; } if (ngx_process >= NGX_PROCESS_WORKER || cycle->old_cycle == NULL || cycle->old_cycle->connection_n < cycle->connection_n) { index = ngx_alloc(sizeof(ngx_event_t *) * 2 * cycle->connection_n, cycle->log); if (index == NULL) { return NGX_ERROR; } if (event_index) { ngx_memcpy(index, event_index, sizeof(ngx_event_t *) * nevents); ngx_free(event_index); } event_index = index; } ngx_io = ngx_os_io; ngx_event_actions = ngx_select_module_ctx.actions; ngx_event_flags = NGX_USE_LEVEL_EVENT; max_fd = -1; return NGX_OK; } static void ngx_select_done(ngx_cycle_t *cycle) { ngx_free(event_index); event_index = NULL; } static ngx_int_t ngx_select_add_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags) { ngx_connection_t *c; c = ev->data; ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0, "select add event fd:%d ev:%i", c->fd, event); if (ev->index != NGX_INVALID_INDEX) { ngx_log_error(NGX_LOG_ALERT, ev->log, 0, "select event fd:%d ev:%i is already set", c->fd, event); return NGX_OK; } if ((event == NGX_READ_EVENT && ev->write) || (event == NGX_WRITE_EVENT && !ev->write)) { ngx_log_error(NGX_LOG_ALERT, ev->log, 0, "invalid select %s event fd:%d ev:%i", ev->write ? "write" : "read", c->fd, event); return NGX_ERROR; } if (event == NGX_READ_EVENT) { FD_SET(c->fd, &master_read_fd_set); } else if (event == NGX_WRITE_EVENT) { FD_SET(c->fd, &master_write_fd_set); } if (max_fd != -1 && max_fd < c->fd) { max_fd = c->fd; } ev->active = 1; event_index[nevents] = ev; ev->index = nevents; nevents++; return NGX_OK; } static ngx_int_t ngx_select_del_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags) { ngx_event_t *e; ngx_connection_t *c; c = ev->data; ev->active = 0; if (ev->index == NGX_INVALID_INDEX) { return NGX_OK; } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0, "select del event fd:%d ev:%i", c->fd, event); if (event == NGX_READ_EVENT) { FD_CLR(c->fd, &master_read_fd_set); } else if (event == NGX_WRITE_EVENT) { FD_CLR(c->fd, &master_write_fd_set); } if (max_fd == c->fd) { max_fd = -1; } if (ev->index < --nevents) { e = event_index[nevents]; event_index[ev->index] = e; e->index = ev->index; } ev->index = NGX_INVALID_INDEX; return NGX_OK; } static ngx_int_t ngx_select_process_events(ngx_cycle_t *cycle, ngx_msec_t timer, ngx_uint_t flags) { int ready, nready; ngx_err_t err; ngx_uint_t i, found; ngx_event_t *ev; ngx_queue_t *queue; struct timeval tv, *tp; ngx_connection_t *c; if (max_fd == -1) { for (i = 0; i < nevents; i++) { c = event_index[i]->data; if (max_fd < c->fd) { max_fd = c->fd; } } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "change max_fd: %i", max_fd); } #if (NGX_DEBUG) if (cycle->log->log_level & NGX_LOG_DEBUG_ALL) { for (i = 0; i < nevents; i++) { ev = event_index[i]; c = ev->data; ngx_log_debug2(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "select event: fd:%d wr:%d", c->fd, ev->write); } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "max_fd: %i", max_fd); } #endif if (timer == NGX_TIMER_INFINITE) { tp = NULL; } else { tv.tv_sec = (long) (timer / 1000); tv.tv_usec = (long) ((timer % 1000) * 1000); tp = &tv; } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "select timer: %M", timer); work_read_fd_set = master_read_fd_set; work_write_fd_set = master_write_fd_set; ready = select(max_fd + 1, &work_read_fd_set, &work_write_fd_set, NULL, tp); err = (ready == -1) ? ngx_errno : 0; if (flags & NGX_UPDATE_TIME || ngx_event_timer_alarm) { ngx_time_update(); } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "select ready %d", ready); if (err) { ngx_uint_t level; if (err == NGX_EINTR) { if (ngx_event_timer_alarm) { ngx_event_timer_alarm = 0; return NGX_OK; } level = NGX_LOG_INFO; } else { level = NGX_LOG_ALERT; } ngx_log_error(level, cycle->log, err, "select() failed"); if (err == NGX_EBADF) { ngx_select_repair_fd_sets(cycle); } return NGX_ERROR; } if (ready == 0) { if (timer != NGX_TIMER_INFINITE) { return NGX_OK; } ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "select() returned no events without timeout"); return NGX_ERROR; } nready = 0; for (i = 0; i < nevents; i++) { ev = event_index[i]; c = ev->data; found = 0; if (ev->write) { if (FD_ISSET(c->fd, &work_write_fd_set)) { found = 1; ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "select write %d", c->fd); } } else { if (FD_ISSET(c->fd, &work_read_fd_set)) { found = 1; ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "select read %d", c->fd); } } if (found) { ev->ready = 1; queue = ev->accept ? &ngx_posted_accept_events : &ngx_posted_events; ngx_post_event(ev, queue); nready++; } } if (ready != nready) { ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "select ready != events: %d:%d", ready, nready); ngx_select_repair_fd_sets(cycle); } return NGX_OK; } static void ngx_select_repair_fd_sets(ngx_cycle_t *cycle) { int n; socklen_t len; ngx_err_t err; ngx_socket_t s; for (s = 0; s <= max_fd; s++) { if (FD_ISSET(s, &master_read_fd_set) == 0) { continue; } len = sizeof(int); if (getsockopt(s, SOL_SOCKET, SO_TYPE, &n, &len) == -1) { err = ngx_socket_errno; ngx_log_error(NGX_LOG_ALERT, cycle->log, err, "invalid descriptor #%d in read fd_set", s); FD_CLR(s, &master_read_fd_set); } } for (s = 0; s <= max_fd; s++) { if (FD_ISSET(s, &master_write_fd_set) == 0) { continue; } len = sizeof(int); if (getsockopt(s, SOL_SOCKET, SO_TYPE, &n, &len) == -1) { err = ngx_socket_errno; ngx_log_error(NGX_LOG_ALERT, cycle->log, err, "invalid descriptor #%d in write fd_set", s); FD_CLR(s, &master_write_fd_set); } } max_fd = -1; } static char * ngx_select_init_conf(ngx_cycle_t *cycle, void *conf) { ngx_event_conf_t *ecf; ecf = ngx_event_get_conf(cycle->conf_ctx, ngx_event_core_module); if (ecf->use != ngx_select_module.ctx_index) { return NGX_CONF_OK; } /* disable warning: the default FD_SETSIZE is 1024U in FreeBSD 5.x */ if (cycle->connection_n > FD_SETSIZE) { ngx_log_error(NGX_LOG_EMERG, cycle->log, 0, "the maximum number of files " "supported by select() is %ud", FD_SETSIZE); return NGX_CONF_ERROR; } return NGX_CONF_OK; }