Mercurial > hg > nginx
view src/event/ngx_event_udp.c @ 9300:5be23505292b
SSI: fixed incorrect or duplicate stub output.
Following 3518:eb3aaf8bd2a9 (0.8.37), r->request_output is only set
if there are data in the first buffer sent in the subrequest. As a
result, following the change mentioned this flag cannot be used to
prevent duplicate ngx_http_ssi_stub_output() calls, since it is not
set if there was already some output, but the first buffer was empty.
Still, when there are multiple subrequests, even an empty subrequest
response might be delayed by the postpone filter, leading to a second
call of ngx_http_ssi_stub_output() during finalization from
ngx_http_writer() the subreqest buffers are released by the postpone
filter. Since r->request_output is not set after the first call, this
resulted in duplicate stub output.
Additionally, checking only the first buffer might be wrong in some
unusual cases. For example, the first buffer might be empty if
$r->flush() is called before printing any data in the embedded Perl
module.
Depending on the postpone_output value and corresponding sizes, this
issue can result in either duplicate or unexpected stub output, or
"zero size buf in writer" alerts.
Following 8124:f5515e727656 (1.23.4), it became slightly easier to
reproduce the issue, as empty static files and empty cache items now
result in a response with an empty buffer. Before the change, an empty
proxied response can be used to reproduce the issue.
Fix is check all buffers and set r->request_output if any non-empty
buffers are sent. This ensures that all unusual cases of non-empty
responses are covered, and also that r->request_output will be set
after the first stub output, preventing duplicate output.
Reported by Jan Gassen.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Thu, 04 Jul 2024 17:41:28 +0300 |
parents | adcc6d8acfd4 |
children |
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/* * Copyright (C) Roman Arutyunyan * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> #if !(NGX_WIN32) static void ngx_close_accepted_udp_connection(ngx_connection_t *c); static ssize_t ngx_udp_shared_recv(ngx_connection_t *c, u_char *buf, size_t size); static ngx_int_t ngx_insert_udp_connection(ngx_connection_t *c); static ngx_connection_t *ngx_lookup_udp_connection(ngx_listening_t *ls, struct sockaddr *sockaddr, socklen_t socklen, struct sockaddr *local_sockaddr, socklen_t local_socklen); void ngx_event_recvmsg(ngx_event_t *ev) { ssize_t n; ngx_buf_t buf; ngx_log_t *log; ngx_err_t err; socklen_t socklen, local_socklen; ngx_event_t *rev, *wev; struct iovec iov[1]; struct msghdr msg; ngx_sockaddr_t sa, lsa; struct sockaddr *sockaddr, *local_sockaddr; ngx_listening_t *ls; ngx_event_conf_t *ecf; ngx_connection_t *c, *lc; static u_char buffer[65535]; #if (NGX_HAVE_ADDRINFO_CMSG) u_char msg_control[CMSG_SPACE(sizeof(ngx_addrinfo_t))]; #endif if (ev->timedout) { if (ngx_enable_accept_events((ngx_cycle_t *) ngx_cycle) != NGX_OK) { return; } ev->timedout = 0; } ecf = ngx_event_get_conf(ngx_cycle->conf_ctx, ngx_event_core_module); if (!(ngx_event_flags & NGX_USE_KQUEUE_EVENT)) { ev->available = ecf->multi_accept; } lc = ev->data; ls = lc->listening; ev->ready = 0; ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0, "recvmsg on %V, ready: %d", &ls->addr_text, ev->available); do { ngx_memzero(&msg, sizeof(struct msghdr)); iov[0].iov_base = (void *) buffer; iov[0].iov_len = sizeof(buffer); msg.msg_name = &sa; msg.msg_namelen = sizeof(ngx_sockaddr_t); msg.msg_iov = iov; msg.msg_iovlen = 1; #if (NGX_HAVE_ADDRINFO_CMSG) if (ls->wildcard) { msg.msg_control = &msg_control; msg.msg_controllen = sizeof(msg_control); ngx_memzero(&msg_control, sizeof(msg_control)); } #endif n = recvmsg(lc->fd, &msg, 0); if (n == -1) { err = ngx_socket_errno; if (err == NGX_EAGAIN) { ngx_log_debug0(NGX_LOG_DEBUG_EVENT, ev->log, err, "recvmsg() not ready"); return; } ngx_log_error(NGX_LOG_ALERT, ev->log, err, "recvmsg() failed"); return; } #if (NGX_HAVE_ADDRINFO_CMSG) if (msg.msg_flags & (MSG_TRUNC|MSG_CTRUNC)) { ngx_log_error(NGX_LOG_ALERT, ev->log, 0, "recvmsg() truncated data"); continue; } #endif sockaddr = msg.msg_name; socklen = msg.msg_namelen; if (socklen > (socklen_t) sizeof(ngx_sockaddr_t)) { socklen = sizeof(ngx_sockaddr_t); } if (socklen == 0) { /* * on Linux recvmsg() returns zero msg_namelen * when receiving packets from unbound AF_UNIX sockets */ socklen = sizeof(struct sockaddr); ngx_memzero(&sa, sizeof(struct sockaddr)); sa.sockaddr.sa_family = ls->sockaddr->sa_family; } local_sockaddr = ls->sockaddr; local_socklen = ls->socklen; #if (NGX_HAVE_ADDRINFO_CMSG) if (ls->wildcard) { struct cmsghdr *cmsg; ngx_memcpy(&lsa, local_sockaddr, local_socklen); local_sockaddr = &lsa.sockaddr; for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) { if (ngx_get_srcaddr_cmsg(cmsg, local_sockaddr) == NGX_OK) { break; } } } #endif c = ngx_lookup_udp_connection(ls, sockaddr, socklen, local_sockaddr, local_socklen); if (c) { #if (NGX_DEBUG) if (c->log->log_level & NGX_LOG_DEBUG_EVENT) { ngx_log_handler_pt handler; handler = c->log->handler; c->log->handler = NULL; ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0, "recvmsg: fd:%d n:%z", c->fd, n); c->log->handler = handler; } #endif ngx_memzero(&buf, sizeof(ngx_buf_t)); buf.pos = buffer; buf.last = buffer + n; rev = c->read; c->udp->buffer = &buf; rev->ready = 1; rev->active = 0; rev->handler(rev); if (c->udp) { c->udp->buffer = NULL; } rev->ready = 0; rev->active = 1; goto next; } #if (NGX_STAT_STUB) (void) ngx_atomic_fetch_add(ngx_stat_accepted, 1); #endif ngx_accept_disabled = ngx_cycle->connection_n / 8 - ngx_cycle->free_connection_n; c = ngx_get_connection(lc->fd, ev->log); if (c == NULL) { return; } c->shared = 1; c->type = SOCK_DGRAM; c->socklen = socklen; #if (NGX_STAT_STUB) (void) ngx_atomic_fetch_add(ngx_stat_active, 1); #endif c->pool = ngx_create_pool(ls->pool_size, ev->log); if (c->pool == NULL) { ngx_close_accepted_udp_connection(c); return; } c->sockaddr = ngx_palloc(c->pool, socklen); if (c->sockaddr == NULL) { ngx_close_accepted_udp_connection(c); return; } ngx_memcpy(c->sockaddr, sockaddr, socklen); log = ngx_palloc(c->pool, sizeof(ngx_log_t)); if (log == NULL) { ngx_close_accepted_udp_connection(c); return; } *log = ls->log; c->recv = ngx_udp_shared_recv; c->send = ngx_udp_send; c->send_chain = ngx_udp_send_chain; c->need_flush_buf = 1; c->log = log; c->pool->log = log; c->listening = ls; if (local_sockaddr == &lsa.sockaddr) { local_sockaddr = ngx_palloc(c->pool, local_socklen); if (local_sockaddr == NULL) { ngx_close_accepted_udp_connection(c); return; } ngx_memcpy(local_sockaddr, &lsa, local_socklen); } c->local_sockaddr = local_sockaddr; c->local_socklen = local_socklen; c->buffer = ngx_create_temp_buf(c->pool, n); if (c->buffer == NULL) { ngx_close_accepted_udp_connection(c); return; } c->buffer->last = ngx_cpymem(c->buffer->last, buffer, n); rev = c->read; wev = c->write; rev->active = 1; wev->ready = 1; rev->log = log; wev->log = log; /* * TODO: MT: - ngx_atomic_fetch_add() * or protection by critical section or light mutex * * TODO: MP: - allocated in a shared memory * - ngx_atomic_fetch_add() * or protection by critical section or light mutex */ c->number = ngx_atomic_fetch_add(ngx_connection_counter, 1); c->start_time = ngx_current_msec; #if (NGX_STAT_STUB) (void) ngx_atomic_fetch_add(ngx_stat_handled, 1); #endif if (ls->addr_ntop) { c->addr_text.data = ngx_pnalloc(c->pool, ls->addr_text_max_len); if (c->addr_text.data == NULL) { ngx_close_accepted_udp_connection(c); return; } c->addr_text.len = ngx_sock_ntop(c->sockaddr, c->socklen, c->addr_text.data, ls->addr_text_max_len, 0); if (c->addr_text.len == 0) { ngx_close_accepted_udp_connection(c); return; } } #if (NGX_DEBUG) { ngx_str_t addr; u_char text[NGX_SOCKADDR_STRLEN]; ngx_debug_accepted_connection(ecf, c); if (log->log_level & NGX_LOG_DEBUG_EVENT) { addr.data = text; addr.len = ngx_sock_ntop(c->sockaddr, c->socklen, text, NGX_SOCKADDR_STRLEN, 1); ngx_log_debug4(NGX_LOG_DEBUG_EVENT, log, 0, "*%uA recvmsg: %V fd:%d n:%z", c->number, &addr, c->fd, n); } } #endif if (ngx_insert_udp_connection(c) != NGX_OK) { ngx_close_accepted_udp_connection(c); return; } log->data = NULL; log->handler = NULL; ls->handler(c); next: if (ngx_event_flags & NGX_USE_KQUEUE_EVENT) { ev->available -= n; } } while (ev->available); } static void ngx_close_accepted_udp_connection(ngx_connection_t *c) { ngx_free_connection(c); c->fd = (ngx_socket_t) -1; if (c->pool) { ngx_destroy_pool(c->pool); } #if (NGX_STAT_STUB) (void) ngx_atomic_fetch_add(ngx_stat_active, -1); #endif } static ssize_t ngx_udp_shared_recv(ngx_connection_t *c, u_char *buf, size_t size) { ssize_t n; ngx_buf_t *b; if (c->udp == NULL || c->udp->buffer == NULL) { return NGX_AGAIN; } b = c->udp->buffer; n = ngx_min(b->last - b->pos, (ssize_t) size); ngx_memcpy(buf, b->pos, n); c->udp->buffer = NULL; c->read->ready = 0; c->read->active = 1; return n; } void ngx_udp_rbtree_insert_value(ngx_rbtree_node_t *temp, ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel) { ngx_int_t rc; ngx_connection_t *c, *ct; ngx_rbtree_node_t **p; ngx_udp_connection_t *udp, *udpt; for ( ;; ) { if (node->key < temp->key) { p = &temp->left; } else if (node->key > temp->key) { p = &temp->right; } else { /* node->key == temp->key */ udp = (ngx_udp_connection_t *) node; c = udp->connection; udpt = (ngx_udp_connection_t *) temp; ct = udpt->connection; rc = ngx_memn2cmp(udp->key.data, udpt->key.data, udp->key.len, udpt->key.len); if (rc == 0 && c->listening->wildcard) { rc = ngx_cmp_sockaddr(c->local_sockaddr, c->local_socklen, ct->local_sockaddr, ct->local_socklen, 1); } p = (rc < 0) ? &temp->left : &temp->right; } if (*p == sentinel) { break; } temp = *p; } *p = node; node->parent = temp; node->left = sentinel; node->right = sentinel; ngx_rbt_red(node); } static ngx_int_t ngx_insert_udp_connection(ngx_connection_t *c) { uint32_t hash; ngx_pool_cleanup_t *cln; ngx_udp_connection_t *udp; if (c->udp) { return NGX_OK; } udp = ngx_pcalloc(c->pool, sizeof(ngx_udp_connection_t)); if (udp == NULL) { return NGX_ERROR; } udp->connection = c; ngx_crc32_init(hash); ngx_crc32_update(&hash, (u_char *) c->sockaddr, c->socklen); if (c->listening->wildcard) { ngx_crc32_update(&hash, (u_char *) c->local_sockaddr, c->local_socklen); } ngx_crc32_final(hash); udp->node.key = hash; udp->key.data = (u_char *) c->sockaddr; udp->key.len = c->socklen; cln = ngx_pool_cleanup_add(c->pool, 0); if (cln == NULL) { return NGX_ERROR; } cln->data = c; cln->handler = ngx_delete_udp_connection; ngx_rbtree_insert(&c->listening->rbtree, &udp->node); c->udp = udp; return NGX_OK; } void ngx_delete_udp_connection(void *data) { ngx_connection_t *c = data; if (c->udp == NULL) { return; } ngx_rbtree_delete(&c->listening->rbtree, &c->udp->node); c->udp = NULL; } static ngx_connection_t * ngx_lookup_udp_connection(ngx_listening_t *ls, struct sockaddr *sockaddr, socklen_t socklen, struct sockaddr *local_sockaddr, socklen_t local_socklen) { uint32_t hash; ngx_int_t rc; ngx_connection_t *c; ngx_rbtree_node_t *node, *sentinel; ngx_udp_connection_t *udp; #if (NGX_HAVE_UNIX_DOMAIN) if (sockaddr->sa_family == AF_UNIX) { struct sockaddr_un *saun = (struct sockaddr_un *) sockaddr; if (socklen <= (socklen_t) offsetof(struct sockaddr_un, sun_path) || saun->sun_path[0] == '\0') { ngx_log_debug0(NGX_LOG_DEBUG_EVENT, ngx_cycle->log, 0, "unbound unix socket"); return NULL; } } #endif node = ls->rbtree.root; sentinel = ls->rbtree.sentinel; ngx_crc32_init(hash); ngx_crc32_update(&hash, (u_char *) sockaddr, socklen); if (ls->wildcard) { ngx_crc32_update(&hash, (u_char *) local_sockaddr, local_socklen); } ngx_crc32_final(hash); while (node != sentinel) { if (hash < node->key) { node = node->left; continue; } if (hash > node->key) { node = node->right; continue; } /* hash == node->key */ udp = (ngx_udp_connection_t *) node; c = udp->connection; rc = ngx_cmp_sockaddr(sockaddr, socklen, c->sockaddr, c->socklen, 1); if (rc == 0 && ls->wildcard) { rc = ngx_cmp_sockaddr(local_sockaddr, local_socklen, c->local_sockaddr, c->local_socklen, 1); } if (rc == 0) { return c; } node = (rc < 0) ? node->left : node->right; } return NULL; } #else void ngx_delete_udp_connection(void *data) { return; } #endif