/* 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_strings.h"

#include "apr_thread_proc.h"    /* for RLIMIT stuff */

#define APR_WANT_STRFUNC

#include "apr_want.h"

#include "httpd.h"

#include "http_config.h"

#include "http_connection.h"

#include "http_core.h"

#include "http_protocol.h"   /* For index_of_response().  Grump. */

#include "http_request.h"

#include "util_filter.h"

#include "util_ebcdic.h"

#include "ap_mpm.h"

#include "scoreboard.h"

#include "mod_core.h"

/* Handles for core filters */

AP_DECLARE_DATA ap_filter_rec_t *ap_http_input_filter_handle;

AP_DECLARE_DATA ap_filter_rec_t *ap_http_header_filter_handle;

AP_DECLARE_DATA ap_filter_rec_t *ap_chunk_filter_handle;

AP_DECLARE_DATA ap_filter_rec_t *ap_http_outerror_filter_handle;

AP_DECLARE_DATA ap_filter_rec_t *ap_byterange_filter_handle;

AP_DECLARE_DATA const char *ap_multipart_boundary;

/* If we are using an MPM That Supports Async Connections,

 * use a different processing function

 */

static int async_mpm = 0;

static const char *set_keep_alive_timeout(cmd_parms *cmd, void *dummy,

                                          const char *arg)

{

    apr_interval_time_t timeout;

    const char *err = ap_check_cmd_context(cmd, NOT_IN_DIR_CONTEXT);

    if (err != NULL) {

        return err;

    }

    /* Stolen from mod_proxy.c */

    if (ap_timeout_parameter_parse(arg, &timeout, "s") != APR_SUCCESS)

        return "KeepAliveTimeout has wrong format";

    cmd->server->keep_alive_timeout = timeout;

    /* We don't want to take into account whether or not KeepAliveTimeout is

     * set for the main server, because if no http_module directive is used

     * for a vhost, it will inherit the http_srv_cfg from the main server.

     * However keep_alive_timeout_set helps determine whether the vhost should

     * use its own configured timeout or the one from the vhost declared first

     * on the same IP:port (ie. c->base_server, and the legacy behaviour).

     */

    if (cmd->server->is_virtual) {

        cmd->server->keep_alive_timeout_set = 1;

    }

    return NULL;

}

static const char *set_keep_alive(cmd_parms *cmd, void *dummy,

                                  int arg)

{

    const char *err = ap_check_cmd_context(cmd, NOT_IN_DIR_CONTEXT);

    if (err != NULL) {

        return err;

    }

    cmd->server->keep_alive = arg;

    return NULL;

}

static const char *set_keep_alive_max(cmd_parms *cmd, void *dummy,

                                      const char *arg)

{

    const char *err = ap_check_cmd_context(cmd, NOT_IN_DIR_CONTEXT);

    if (err != NULL) {

        return err;

    }

    cmd->server->keep_alive_max = atoi(arg);

    return NULL;

}

static const command_rec http_cmds[] = {

    AP_INIT_TAKE1("KeepAliveTimeout", set_keep_alive_timeout, NULL, RSRC_CONF,

                  "Keep-Alive timeout duration (sec)"),

    AP_INIT_TAKE1("MaxKeepAliveRequests", set_keep_alive_max, NULL, RSRC_CONF,

                  "Maximum number of Keep-Alive requests per connection, "

                  "or 0 for infinite"),

    AP_INIT_FLAG("KeepAlive", set_keep_alive, NULL, RSRC_CONF,

                  "Whether persistent connections should be On or Off"),

    { NULL }

};

static const char *http_scheme(const request_rec *r)

{

    /*

     * The http module shouldn't return anything other than

     * "http" (the default) or "https".

     */

    if (r->server->server_scheme &&

        (strcmp(r->server->server_scheme, "https") == 0))

        return "https";

    return "http";

}

static apr_port_t http_port(const request_rec *r)

{

    if (r->server->server_scheme &&

        (strcmp(r->server->server_scheme, "https") == 0))

        return DEFAULT_HTTPS_PORT;

    return DEFAULT_HTTP_PORT;

}

static int ap_process_http_async_connection(conn_rec *c)

{

    request_rec *r = NULL;

    conn_state_t *cs = c->cs;

    AP_DEBUG_ASSERT(cs != NULL);

    AP_DEBUG_ASSERT(cs->state == CONN_STATE_READ_REQUEST_LINE);

    while (cs->state == CONN_STATE_READ_REQUEST_LINE) {

        ap_update_child_status_from_conn(c->sbh, SERVER_BUSY_READ, c);

        if ((r = ap_read_request(c))) {

            c->keepalive = AP_CONN_UNKNOWN;

            /* process the request if it was read without error */

            if (r->status == HTTP_OK) {

                cs->state = CONN_STATE_HANDLER;

                ap_update_child_status(c->sbh, SERVER_BUSY_WRITE, r);

                ap_process_async_request(r);

                /* After the call to ap_process_request, the

                 * request pool may have been deleted.  We set

                 * r=NULL here to ensure that any dereference

                 * of r that might be added later in this function

                 * will result in a segfault immediately instead

                 * of nondeterministic failures later.

                 */

                r = NULL;

            }

            if (cs->state != CONN_STATE_WRITE_COMPLETION &&

                cs->state != CONN_STATE_SUSPENDED) {

                /* Something went wrong; close the connection */

                cs->state = CONN_STATE_LINGER;

            }

        }

        else {   /* ap_read_request failed - client may have closed */

            cs->state = CONN_STATE_LINGER;

        }

    }

    return OK;

}

static int ap_process_http_sync_connection(conn_rec *c)

{

    request_rec *r;

    conn_state_t *cs = c->cs;

    apr_socket_t *csd = NULL;

    int mpm_state = 0;

    /*

     * Read and process each request found on our connection

     * until no requests are left or we decide to close.

     */

    ap_update_child_status_from_conn(c->sbh, SERVER_BUSY_READ, c);

    while ((r = ap_read_request(c)) != NULL) {

        apr_interval_time_t keep_alive_timeout = r->server->keep_alive_timeout;

        /* To preserve legacy behaviour, use the keepalive timeout from the

         * base server (first on this IP:port) when none is explicitly

         * configured on this server.

         */

        if (!r->server->keep_alive_timeout_set) {

            keep_alive_timeout = c->base_server->keep_alive_timeout;

        }

        c->keepalive = AP_CONN_UNKNOWN;

        /* process the request if it was read without error */

        if (r->status == HTTP_OK) {

            if (cs)

                cs->state = CONN_STATE_HANDLER;

            ap_update_child_status(c->sbh, SERVER_BUSY_WRITE, r);

            ap_process_request(r);

            /* After the call to ap_process_request, the

             * request pool will have been deleted.  We set

             * r=NULL here to ensure that any dereference

             * of r that might be added later in this function

             * will result in a segfault immediately instead

             * of nondeterministic failures later.

             */

            r = NULL;

        }

        if (c->keepalive != AP_CONN_KEEPALIVE || c->aborted)

            break;

        ap_update_child_status(c->sbh, SERVER_BUSY_KEEPALIVE, NULL);

        if (ap_mpm_query(AP_MPMQ_MPM_STATE, &mpm_state)) {

            break;

        }

        if (mpm_state == AP_MPMQ_STOPPING) {

          break;

        }

        if (!csd) {

            csd = ap_get_conn_socket(c);

        }

        apr_socket_opt_set(csd, APR_INCOMPLETE_READ, 1);

        apr_socket_timeout_set(csd, keep_alive_timeout);

        /* Go straight to select() to wait for the next request */

    }

    return OK;

}

static int ap_process_http_connection(conn_rec *c)

{

    if (async_mpm && !c->clogging_input_filters) {

        return ap_process_http_async_connection(c);

    }

    else {

        return ap_process_http_sync_connection(c);

    }

}

static int http_create_request(request_rec *r)

{

    if (!r->main && !r->prev) {

        ap_add_output_filter_handle(ap_byterange_filter_handle,

                                    NULL, r, r->connection);

        ap_add_output_filter_handle(ap_content_length_filter_handle,

                                    NULL, r, r->connection);

        ap_add_output_filter_handle(ap_http_header_filter_handle,

                                    NULL, r, r->connection);

        ap_add_output_filter_handle(ap_http_outerror_filter_handle,

                                    NULL, r, r->connection);

    }

    return OK;

}

static int http_send_options(request_rec *r)

{

    if ((r->method_number == M_OPTIONS) && r->uri && (r->uri[0] == '*') &&

         (r->uri[1] == '\0')) {

        return DONE;           /* Send HTTP pong, without Allow header */

    }

    return DECLINED;

}

static int http_post_config(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp, server_rec *s)

{

    apr_uint64_t val;

    if (ap_mpm_query(AP_MPMQ_IS_ASYNC, &async_mpm) != APR_SUCCESS) {

        async_mpm = 0;

    }

    ap_random_insecure_bytes(&val, sizeof(val));

    ap_multipart_boundary = apr_psprintf(p, "%0" APR_UINT64_T_HEX_FMT, val);

    return OK;

}

static void register_hooks(apr_pool_t *p)

{

    ap_hook_post_config(http_post_config, NULL, NULL, APR_HOOK_MIDDLE);

    ap_hook_process_connection(ap_process_http_connection, NULL, NULL,

                               APR_HOOK_REALLY_LAST);

    ap_hook_map_to_storage(ap_send_http_trace,NULL,NULL,APR_HOOK_MIDDLE);

    ap_hook_map_to_storage(http_send_options,NULL,NULL,APR_HOOK_MIDDLE);

    ap_hook_http_scheme(http_scheme,NULL,NULL,APR_HOOK_REALLY_LAST);

    ap_hook_default_port(http_port,NULL,NULL,APR_HOOK_REALLY_LAST);

    ap_hook_create_request(http_create_request, NULL, NULL, APR_HOOK_REALLY_LAST);

    ap_http_input_filter_handle =

        ap_register_input_filter("HTTP_IN", ap_http_filter,

                                 NULL, AP_FTYPE_PROTOCOL);

    ap_http_header_filter_handle =

        ap_register_output_filter("HTTP_HEADER", ap_http_header_filter,

                                  NULL, AP_FTYPE_PROTOCOL);

    ap_chunk_filter_handle =

        ap_register_output_filter("CHUNK", ap_http_chunk_filter,

                                  NULL, AP_FTYPE_TRANSCODE);

    ap_http_outerror_filter_handle =

        ap_register_output_filter("HTTP_OUTERROR", ap_http_outerror_filter,

                                  NULL, AP_FTYPE_PROTOCOL);

    ap_byterange_filter_handle =

        ap_register_output_filter("BYTERANGE", ap_byterange_filter,

                                  NULL, AP_FTYPE_PROTOCOL);

    ap_method_registry_init(p);

}

AP_DECLARE_MODULE(http) = {

    STANDARD20_MODULE_STUFF,

    NULL,              /* create per-directory config structure */

    NULL,              /* merge per-directory config structures */

    NULL,              /* create per-server config structure */

    NULL,              /* merge per-server config structures */

    http_cmds,         /* command apr_table_t */

    register_hooks     /* register hooks */

};