/* 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 "httpd.h"

#include "http_core.h"

#include "util_filter.h"

#include "http_log.h"

#include "http_config.h"

#include "http_request.h"

#include "http_protocol.h"

#include "ap_mpm.h"

module AP_MODULE_DECLARE_DATA dialup_module;

typedef struct dialup_dcfg_t {

    apr_size_t bytes_per_second;

} dialup_dcfg_t;

typedef struct dialup_baton_t {

    apr_size_t bytes_per_second;

    request_rec *r;

    apr_file_t *fd;

    apr_bucket_brigade *bb;

    apr_bucket_brigade *tmpbb;

} dialup_baton_t;

static int

dialup_send_pulse(dialup_baton_t *db)

{

    int status;

    apr_off_t len = 0;

    apr_size_t bytes_sent = 0;

    while (!APR_BRIGADE_EMPTY(db->bb) && bytes_sent < db->bytes_per_second) {

        apr_bucket *e;

        if (db->r->connection->aborted) {

            return HTTP_INTERNAL_SERVER_ERROR;

        }

        status = apr_brigade_partition(db->bb, db->bytes_per_second, &e);

        if (status != APR_SUCCESS && status != APR_INCOMPLETE) {

            /* XXXXXX: Log me. */

            return HTTP_INTERNAL_SERVER_ERROR;

        }

        if (e != APR_BRIGADE_SENTINEL(db->bb)) {

            apr_bucket *f;

            apr_bucket *b = APR_BUCKET_PREV(e);

            f = APR_RING_FIRST(&db->bb->list);

            APR_RING_UNSPLICE(f, b, link);

            APR_RING_SPLICE_HEAD(&db->tmpbb->list, f, b, apr_bucket, link);

        }

        else {

            APR_BRIGADE_CONCAT(db->tmpbb, db->bb);

        }

        e = apr_bucket_flush_create(db->r->connection->bucket_alloc);

        APR_BRIGADE_INSERT_TAIL(db->tmpbb, e);

        apr_brigade_length(db->tmpbb, 1, &len;;

        bytes_sent += len;

        status = ap_pass_brigade(db->r->output_filters, db->tmpbb);

        apr_brigade_cleanup(db->tmpbb);

        if (status != APR_SUCCESS) {

            ap_log_rerror(APLOG_MARK, APLOG_ERR, status, db->r, APLOGNO(01867)

                          "dialup: pulse: ap_pass_brigade failed:");

            return AP_FILTER_ERROR;

        }

    }

    if (APR_BRIGADE_EMPTY(db->bb)) {

        return DONE;

    }

    else {

        return SUSPENDED;

    }

}

static void

dialup_callback(void *baton)

{

    int status;

    dialup_baton_t *db = (dialup_baton_t *)baton;

    apr_thread_mutex_lock(db->r->invoke_mtx);

    status = dialup_send_pulse(db);

    if (status == SUSPENDED) {

        ap_mpm_register_timed_callback(apr_time_from_sec(1), dialup_callback, baton);

    }

    else if (status == DONE) {

        apr_thread_mutex_unlock(db->r->invoke_mtx);

        ap_finalize_request_protocol(db->r);

        ap_process_request_after_handler(db->r);

        return;

    }

    else {

        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, db->r, APLOGNO(01868)

                      "dialup: pulse returned: %d", status);

        db->r->status = HTTP_OK;

        ap_die(status, db->r);

    }

    apr_thread_mutex_unlock(db->r->invoke_mtx);

}

static int

dialup_handler(request_rec *r)

{

    int status;

    apr_status_t rv;

    dialup_dcfg_t *dcfg;

    core_dir_config *ccfg;

    apr_file_t *fd;

    dialup_baton_t *db;

    apr_bucket *e;

    /* See core.c, default handler for all of the cases we just decline. */

    if (r->method_number != M_GET ||

        r->finfo.filetype == APR_NOFILE ||

        r->finfo.filetype == APR_DIR) {

        return DECLINED;

    }

    dcfg = ap_get_module_config(r->per_dir_config,

                                &dialup_module);

    if (dcfg->bytes_per_second == 0) {

        return DECLINED;

    }

    ccfg = ap_get_core_module_config(r->per_dir_config);

    rv = apr_file_open(&fd, r->filename, APR_READ | APR_BINARY

#if APR_HAS_SENDFILE

                           | AP_SENDFILE_ENABLED(ccfg->enable_sendfile)

#endif

                       , 0, r->pool);

    if (rv) {

        return DECLINED;

    }

    /* copied from default handler: */

    ap_update_mtime(r, r->finfo.mtime);

    ap_set_last_modified(r);

    ap_set_etag(r);

    ap_set_accept_ranges(r);

    ap_set_content_length(r, r->finfo.size);

    status = ap_meets_conditions(r);

    if (status != OK) {

        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01869)

                      "dialup: declined, meets conditions, good luck core handler");

        return DECLINED;

    }

    db = apr_palloc(r->pool, sizeof(dialup_baton_t));

    db->bb = apr_brigade_create(r->pool, r->connection->bucket_alloc);

    db->tmpbb = apr_brigade_create(r->pool, r->connection->bucket_alloc);

    e = apr_brigade_insert_file(db->bb, fd, 0, r->finfo.size, r->pool);

#if APR_HAS_MMAP

    if (ccfg->enable_mmap == ENABLE_MMAP_OFF) {

        apr_bucket_file_enable_mmap(e, 0);

    }

#endif

    db->bytes_per_second = dcfg->bytes_per_second;

    db->r = r;

    db->fd = fd;

    e = apr_bucket_eos_create(r->connection->bucket_alloc);

    APR_BRIGADE_INSERT_TAIL(db->bb, e);

    status = dialup_send_pulse(db);

    if (status != SUSPENDED && status != DONE) {

        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01870)

                      "dialup: failed, send pulse");

        return status;

    }

    ap_mpm_register_timed_callback(apr_time_from_sec(1), dialup_callback, db);

    return SUSPENDED;

}

#ifndef APR_HOOK_ALMOST_LAST

#define APR_HOOK_ALMOST_LAST (APR_HOOK_REALLY_LAST - 1)

#endif

static void

dialup_register_hooks(apr_pool_t *p)

{

    ap_hook_handler(dialup_handler, NULL, NULL, APR_HOOK_ALMOST_LAST);

}

typedef struct modem_speed_t {

    const char *name;

    apr_size_t bytes_per_second;

} modem_speed_t;

#ifndef BITRATE_TO_BYTES

#define BITRATE_TO_BYTES(x) ((1000 * x)/8)

#endif

static const modem_speed_t modem_bitrates[] =

{

    {"V.21",    BITRATE_TO_BYTES(0.1)},

    {"V.26bis", BITRATE_TO_BYTES(2.4)},

    {"V.32",    BITRATE_TO_BYTES(9.6)},

    {"V.34",    BITRATE_TO_BYTES(28.8)},

    {"V.92",    BITRATE_TO_BYTES(56.0)},

    {"i-was-rich-and-got-a-leased-line", BITRATE_TO_BYTES(1500)},

    {NULL, 0}

};

static const char *

cmd_modem_standard(cmd_parms *cmd,

             void *dconf,

             const char *input)

{

    const modem_speed_t *standard;

    int i = 0;

    dialup_dcfg_t *dcfg = (dialup_dcfg_t*)dconf;

    dcfg->bytes_per_second = 0;

    while (modem_bitrates[i].name != NULL) {

        standard = &modem_bitrates[i];

        if (strcasecmp(standard->name, input) == 0) {

            dcfg->bytes_per_second = standard->bytes_per_second;

            break;

        }

        i++;

    }

    if (dcfg->bytes_per_second == 0) {

        return "mod_diaulup: Unkonwn Modem Standard specified.";

    }

    return NULL;

}

static void *

dialup_dcfg_create(apr_pool_t *p, char *dummy)

{

    dialup_dcfg_t *cfg = apr_palloc(p, sizeof(dialup_dcfg_t));

    cfg->bytes_per_second = 0;

    return cfg;

}

static const command_rec dialup_cmds[] =

{

    AP_INIT_TAKE1("ModemStandard", cmd_modem_standard, NULL, ACCESS_CONF,

                  "Modem Standard to.. simulate. "

                  "Must be one of: 'V.21', 'V.26bis', 'V.32', 'V.34', or 'V.92'"),

    {NULL}

};

AP_DECLARE_MODULE(dialup) =

{

    STANDARD20_MODULE_STUFF,

    dialup_dcfg_create,

    NULL,

    NULL,

    NULL,

    dialup_cmds,

    dialup_register_hooks

};