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+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "apr.h"
+#include "apr_strings.h"
+
+#include "ap_config.h"
+#include "httpd.h"
+#include "http_connection.h"
+#include "http_request.h"
+#include "http_protocol.h"
+#include "ap_mpm.h"
+#include "http_config.h"
+#include "http_core.h"
+#include "http_vhost.h"
+#include "scoreboard.h"
+#include "http_log.h"
+#include "util_filter.h"
+
+APR_HOOK_STRUCT(
+ APR_HOOK_LINK(create_connection)
+ APR_HOOK_LINK(process_connection)
+ APR_HOOK_LINK(pre_connection)
+ APR_HOOK_LINK(pre_close_connection)
+)
+AP_IMPLEMENT_HOOK_RUN_FIRST(conn_rec *,create_connection,
+ (apr_pool_t *p, server_rec *server, apr_socket_t *csd, long conn_id, void *sbh, apr_bucket_alloc_t *alloc),
+ (p, server, csd, conn_id, sbh, alloc), NULL)
+AP_IMPLEMENT_HOOK_RUN_FIRST(int,process_connection,(conn_rec *c),(c),DECLINED)
+AP_IMPLEMENT_HOOK_RUN_ALL(int,pre_connection,(conn_rec *c, void *csd),(c, csd),OK,DECLINED)
+AP_IMPLEMENT_HOOK_RUN_ALL(int,pre_close_connection,(conn_rec *c),(c),OK,DECLINED)
+
+/*
+ * More machine-dependent networking gooo... on some systems,
+ * you've got to be *really* sure that all the packets are acknowledged
+ * before closing the connection, since the client will not be able
+ * to see the last response if their TCP buffer is flushed by a RST
+ * packet from us, which is what the server's TCP stack will send
+ * if it receives any request data after closing the connection.
+ *
+ * In an ideal world, this function would be accomplished by simply
+ * setting the socket option SO_LINGER and handling it within the
+ * server's TCP stack while the process continues on to the next request.
+ * Unfortunately, it seems that most (if not all) operating systems
+ * block the server process on close() when SO_LINGER is used.
+ * For those that don't, see USE_SO_LINGER below. For the rest,
+ * we have created a home-brew lingering_close.
+ *
+ * Many operating systems tend to block, puke, or otherwise mishandle
+ * calls to shutdown only half of the connection. You should define
+ * NO_LINGCLOSE in ap_config.h if such is the case for your system.
+ */
+#ifndef MAX_SECS_TO_LINGER
+#define MAX_SECS_TO_LINGER 30
+#endif
+
+AP_CORE_DECLARE(apr_status_t) ap_shutdown_conn(conn_rec *c, int flush)
+{
+ apr_status_t rv;
+ apr_bucket_brigade *bb;
+ apr_bucket *b;
+
+ bb = apr_brigade_create(c->pool, c->bucket_alloc);
+
+ if (flush) {
+ /* FLUSH bucket */
+ b = apr_bucket_flush_create(c->bucket_alloc);
+ APR_BRIGADE_INSERT_TAIL(bb, b);
+ }
+
+ /* End Of Connection bucket */
+ b = ap_bucket_eoc_create(c->bucket_alloc);
+ APR_BRIGADE_INSERT_TAIL(bb, b);
+
+ rv = ap_pass_brigade(c->output_filters, bb);
+ apr_brigade_destroy(bb);
+ return rv;
+}
+
+AP_CORE_DECLARE(void) ap_flush_conn(conn_rec *c)
+{
+ (void)ap_shutdown_conn(c, 1);
+}
+
+AP_DECLARE(int) ap_prep_lingering_close(conn_rec *c)
+{
+ /* Give protocol handlers one last chance to raise their voice */
+ ap_run_pre_close_connection(c);
+
+ if (c->sbh) {
+ ap_update_child_status(c->sbh, SERVER_CLOSING, NULL);
+ }
+ return 0;
+}
+
+/* we now proceed to read from the client until we get EOF, or until
+ * MAX_SECS_TO_LINGER has passed. The reasons for doing this are
+ * documented in a draft:
+ *
+ * http://tools.ietf.org/html/draft-ietf-http-connection-00.txt
+ *
+ * in a nutshell -- if we don't make this effort we risk causing
+ * TCP RST packets to be sent which can tear down a connection before
+ * all the response data has been sent to the client.
+ */
+#define SECONDS_TO_LINGER 2
+
+AP_DECLARE(int) ap_start_lingering_close(conn_rec *c)
+{
+ apr_socket_t *csd = ap_get_conn_socket(c);
+
+ ap_assert(csd != NULL);
+
+ if (ap_prep_lingering_close(c)) {
+ return 1;
+ }
+
+ /* Close the connection, being careful to send out whatever is still
+ * in our buffers. If possible, try to avoid a hard close until the
+ * client has ACKed our FIN and/or has stopped sending us data.
+ */
+
+ /* Send any leftover data to the client, but never try to again */
+ ap_flush_conn(c);
+
+#ifdef NO_LINGCLOSE
+ return 1;
+#else
+ /* Shut down the socket for write, which will send a FIN
+ * to the peer.
+ */
+ return (c->aborted || apr_socket_shutdown(csd, APR_SHUTDOWN_WRITE));
+#endif
+}
+
+AP_DECLARE(void) ap_lingering_close(conn_rec *c)
+{
+ char dummybuf[512];
+ apr_size_t nbytes;
+ apr_time_t now, timeup = 0;
+ apr_socket_t *csd = ap_get_conn_socket(c);
+
+ if (!csd) {
+ /* Be safe with third-party modules that:
+ * ap_set_core_module_config(c->conn_config, NULL)
+ * to no-op ap_lingering_close().
+ */
+ c->aborted = 1;
+ return;
+ }
+
+ if (ap_start_lingering_close(c)) {
+ apr_socket_close(csd);
+ return;
+ }
+
+ /* Read available data from the client whilst it continues sending
+ * it, for a maximum time of MAX_SECS_TO_LINGER. If the client
+ * does not send any data within 2 seconds (a value pulled from
+ * Apache 1.3 which seems to work well), give up.
+ */
+ apr_socket_timeout_set(csd, apr_time_from_sec(SECONDS_TO_LINGER));
+ apr_socket_opt_set(csd, APR_INCOMPLETE_READ, 1);
+
+ /* The common path here is that the initial apr_socket_recv() call
+ * will return 0 bytes read; so that case must avoid the expensive
+ * apr_time_now() call and time arithmetic. */
+
+ do {
+ nbytes = sizeof(dummybuf);
+ if (apr_socket_recv(csd, dummybuf, &nbytes) || nbytes == 0)
+ break;
+
+ now = apr_time_now();
+ if (timeup == 0) {
+ /*
+ * First time through;
+ * calculate now + 30 seconds (MAX_SECS_TO_LINGER).
+ *
+ * If some module requested a shortened waiting period, only wait for
+ * 2s (SECONDS_TO_LINGER). This is useful for mitigating certain
+ * DoS attacks.
+ */
+ if (apr_table_get(c->notes, "short-lingering-close")) {
+ timeup = now + apr_time_from_sec(SECONDS_TO_LINGER);
+ }
+ else {
+ timeup = now + apr_time_from_sec(MAX_SECS_TO_LINGER);
+ }
+ continue;
+ }
+ } while (now < timeup);
+
+ apr_socket_close(csd);
+}
+
+AP_CORE_DECLARE(void) ap_process_connection(conn_rec *c, void *csd)
+{
+ ap_update_vhost_given_ip(c);
+
+ ap_pre_connection(c, csd);
+
+ if (!c->aborted) {
+ ap_run_process_connection(c);
+ }
+}