Mercurial > hg > nginx
view src/stream/ngx_stream_handler.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 | 3908156a51fa |
children | 893b3313f53c |
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/* * Copyright (C) Roman Arutyunyan * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> #include <ngx_stream.h> static void ngx_stream_log_session(ngx_stream_session_t *s); static void ngx_stream_close_connection(ngx_connection_t *c); static u_char *ngx_stream_log_error(ngx_log_t *log, u_char *buf, size_t len); static void ngx_stream_proxy_protocol_handler(ngx_event_t *rev); void ngx_stream_init_connection(ngx_connection_t *c) { u_char text[NGX_SOCKADDR_STRLEN]; size_t len; ngx_uint_t i; ngx_time_t *tp; ngx_event_t *rev; struct sockaddr *sa; ngx_stream_port_t *port; struct sockaddr_in *sin; ngx_stream_in_addr_t *addr; ngx_stream_session_t *s; ngx_stream_addr_conf_t *addr_conf; #if (NGX_HAVE_INET6) struct sockaddr_in6 *sin6; ngx_stream_in6_addr_t *addr6; #endif ngx_stream_core_srv_conf_t *cscf; ngx_stream_core_main_conf_t *cmcf; /* find the server configuration for the address:port */ port = c->listening->servers; if (port->naddrs > 1) { /* * There are several addresses on this port and one of them * is the "*:port" wildcard so getsockname() is needed to determine * the server address. * * AcceptEx() and recvmsg() already gave this address. */ if (ngx_connection_local_sockaddr(c, NULL, 0) != NGX_OK) { ngx_stream_close_connection(c); return; } sa = c->local_sockaddr; switch (sa->sa_family) { #if (NGX_HAVE_INET6) case AF_INET6: sin6 = (struct sockaddr_in6 *) sa; addr6 = port->addrs; /* the last address is "*" */ for (i = 0; i < port->naddrs - 1; i++) { if (ngx_memcmp(&addr6[i].addr6, &sin6->sin6_addr, 16) == 0) { break; } } addr_conf = &addr6[i].conf; break; #endif default: /* AF_INET */ sin = (struct sockaddr_in *) sa; addr = port->addrs; /* the last address is "*" */ for (i = 0; i < port->naddrs - 1; i++) { if (addr[i].addr == sin->sin_addr.s_addr) { break; } } addr_conf = &addr[i].conf; break; } } else { switch (c->local_sockaddr->sa_family) { #if (NGX_HAVE_INET6) case AF_INET6: addr6 = port->addrs; addr_conf = &addr6[0].conf; break; #endif default: /* AF_INET */ addr = port->addrs; addr_conf = &addr[0].conf; break; } } s = ngx_pcalloc(c->pool, sizeof(ngx_stream_session_t)); if (s == NULL) { ngx_stream_close_connection(c); return; } s->signature = NGX_STREAM_MODULE; s->main_conf = addr_conf->ctx->main_conf; s->srv_conf = addr_conf->ctx->srv_conf; #if (NGX_STREAM_SSL) s->ssl = addr_conf->ssl; #endif if (c->buffer) { s->received += c->buffer->last - c->buffer->pos; } s->connection = c; c->data = s; cscf = ngx_stream_get_module_srv_conf(s, ngx_stream_core_module); ngx_set_connection_log(c, cscf->error_log); len = ngx_sock_ntop(c->sockaddr, c->socklen, text, NGX_SOCKADDR_STRLEN, 1); ngx_log_error(NGX_LOG_INFO, c->log, 0, "*%uA %sclient %*s connected to %V", c->number, c->type == SOCK_DGRAM ? "udp " : "", len, text, &addr_conf->addr_text); c->log->connection = c->number; c->log->handler = ngx_stream_log_error; c->log->data = s; c->log->action = "initializing session"; c->log_error = NGX_ERROR_INFO; s->ctx = ngx_pcalloc(c->pool, sizeof(void *) * ngx_stream_max_module); if (s->ctx == NULL) { ngx_stream_close_connection(c); return; } cmcf = ngx_stream_get_module_main_conf(s, ngx_stream_core_module); s->variables = ngx_pcalloc(s->connection->pool, cmcf->variables.nelts * sizeof(ngx_stream_variable_value_t)); if (s->variables == NULL) { ngx_stream_close_connection(c); return; } tp = ngx_timeofday(); s->start_sec = tp->sec; s->start_msec = tp->msec; rev = c->read; rev->handler = ngx_stream_session_handler; if (addr_conf->proxy_protocol) { c->log->action = "reading PROXY protocol"; rev->handler = ngx_stream_proxy_protocol_handler; if (!rev->ready) { ngx_add_timer(rev, cscf->proxy_protocol_timeout); if (ngx_handle_read_event(rev, 0) != NGX_OK) { ngx_stream_finalize_session(s, NGX_STREAM_INTERNAL_SERVER_ERROR); } return; } } if (ngx_use_accept_mutex) { ngx_post_event(rev, &ngx_posted_events); return; } rev->handler(rev); } static void ngx_stream_proxy_protocol_handler(ngx_event_t *rev) { u_char *p, buf[NGX_PROXY_PROTOCOL_MAX_HEADER]; size_t size; ssize_t n; ngx_err_t err; ngx_connection_t *c; ngx_stream_session_t *s; ngx_stream_core_srv_conf_t *cscf; c = rev->data; s = c->data; ngx_log_debug0(NGX_LOG_DEBUG_STREAM, c->log, 0, "stream PROXY protocol handler"); if (rev->timedout) { ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out"); ngx_stream_finalize_session(s, NGX_STREAM_OK); return; } n = recv(c->fd, (char *) buf, sizeof(buf), MSG_PEEK); err = ngx_socket_errno; ngx_log_debug1(NGX_LOG_DEBUG_STREAM, c->log, 0, "recv(): %z", n); if (n == -1) { if (err == NGX_EAGAIN) { rev->ready = 0; if (!rev->timer_set) { cscf = ngx_stream_get_module_srv_conf(s, ngx_stream_core_module); ngx_add_timer(rev, cscf->proxy_protocol_timeout); } if (ngx_handle_read_event(rev, 0) != NGX_OK) { ngx_stream_finalize_session(s, NGX_STREAM_INTERNAL_SERVER_ERROR); } return; } ngx_connection_error(c, err, "recv() failed"); ngx_stream_finalize_session(s, NGX_STREAM_OK); return; } if (rev->timer_set) { ngx_del_timer(rev); } p = ngx_proxy_protocol_read(c, buf, buf + n); if (p == NULL) { ngx_stream_finalize_session(s, NGX_STREAM_BAD_REQUEST); return; } size = p - buf; if (c->recv(c, buf, size) != (ssize_t) size) { ngx_stream_finalize_session(s, NGX_STREAM_INTERNAL_SERVER_ERROR); return; } c->log->action = "initializing session"; ngx_stream_session_handler(rev); } void ngx_stream_session_handler(ngx_event_t *rev) { ngx_connection_t *c; ngx_stream_session_t *s; c = rev->data; s = c->data; ngx_stream_core_run_phases(s); } void ngx_stream_finalize_session(ngx_stream_session_t *s, ngx_uint_t rc) { ngx_log_debug1(NGX_LOG_DEBUG_STREAM, s->connection->log, 0, "finalize stream session: %i", rc); s->status = rc; ngx_stream_log_session(s); ngx_stream_close_connection(s->connection); } static void ngx_stream_log_session(ngx_stream_session_t *s) { ngx_uint_t i, n; ngx_stream_handler_pt *log_handler; ngx_stream_core_main_conf_t *cmcf; cmcf = ngx_stream_get_module_main_conf(s, ngx_stream_core_module); log_handler = cmcf->phases[NGX_STREAM_LOG_PHASE].handlers.elts; n = cmcf->phases[NGX_STREAM_LOG_PHASE].handlers.nelts; for (i = 0; i < n; i++) { log_handler[i](s); } } static void ngx_stream_close_connection(ngx_connection_t *c) { ngx_pool_t *pool; ngx_log_debug1(NGX_LOG_DEBUG_STREAM, c->log, 0, "close stream connection: %d", c->fd); #if (NGX_STREAM_SSL) if (c->ssl) { if (ngx_ssl_shutdown(c) == NGX_AGAIN) { c->ssl->handler = ngx_stream_close_connection; return; } } #endif #if (NGX_STAT_STUB) (void) ngx_atomic_fetch_add(ngx_stat_active, -1); #endif pool = c->pool; ngx_close_connection(c); ngx_destroy_pool(pool); } static u_char * ngx_stream_log_error(ngx_log_t *log, u_char *buf, size_t len) { u_char *p; ngx_stream_session_t *s; if (log->action) { p = ngx_snprintf(buf, len, " while %s", log->action); len -= p - buf; buf = p; } s = log->data; p = ngx_snprintf(buf, len, ", %sclient: %V, server: %V", s->connection->type == SOCK_DGRAM ? "udp " : "", &s->connection->addr_text, &s->connection->listening->addr_text); len -= p - buf; buf = p; if (s->log_handler) { p = s->log_handler(log, buf, len); } return p; }