Mercurial > hg > nginx-quic
view src/event/modules/ngx_select_module.c @ 8895:457afc332c67
Stream: don't flush empty buffers created for read errors.
When we generate the last_buf buffer for an UDP upstream recv error, it does
not contain any data from the wire. ngx_stream_write_filter attempts to forward
it anyways, which is incorrect (e.g., UDP upstream ECONNREFUSED will be
translated to an empty packet).
This happens because we mark the buffer as both 'flush' and 'last_buf', and
ngx_stream_write_filter has special handling for flush with certain types of
connections (see d127837c714f, 32b0ba4855a6). The flags are meant to be
mutually exclusive, so the fix is to ensure that flush and last_buf are not set
at the same time.
Reproduction:
stream {
upstream unreachable {
server 127.0.0.1:8880;
}
server {
listen 127.0.0.1:8998 udp;
proxy_pass unreachable;
}
}
1 0.000000000 127.0.0.1 → 127.0.0.1 UDP 47 45588 → 8998 Len=5
2 0.000166300 127.0.0.1 → 127.0.0.1 UDP 47 51149 → 8880 Len=5
3 0.000172600 127.0.0.1 → 127.0.0.1 ICMP 75 Destination unreachable (Port
unreachable)
4 0.000202400 127.0.0.1 → 127.0.0.1 UDP 42 8998 → 45588 Len=0
Fixes d127837c714f.
author | Aleksei Bavshin <a.bavshin@f5.com> |
---|---|
date | Mon, 23 May 2022 11:29:44 -0700 |
parents | efd71d49bde0 |
children |
line wrap: on
line source
/* * 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"); static 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; ev->available = -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; }