modules/proxy/mod_proxy_balancer.c

	mod_proxy_balancer.c revision de446ce1c5cc5df1bb4e530c7e4495b56c7572fc
0734f81384d5f2528bb119f89d135043a280d5b2minfrin/* Licensed to the Apache Software Foundation (ASF) under one or more
0734f81384d5f2528bb119f89d135043a280d5b2minfrin * contributor license agreements.  See the NOTICE file distributed with
0734f81384d5f2528bb119f89d135043a280d5b2minfrin * this work for additional information regarding copyright ownership.
d96cf063f04828102edbb0b4987c34b490e2731cnd * The ASF licenses this file to You under the Apache License, Version 2.0
0734f81384d5f2528bb119f89d135043a280d5b2minfrin * (the "License"); you may not use this file except in compliance with
0734f81384d5f2528bb119f89d135043a280d5b2minfrin * the License.  You may obtain a copy of the License at
0734f81384d5f2528bb119f89d135043a280d5b2minfrin *
0734f81384d5f2528bb119f89d135043a280d5b2minfrin *     http://www.apache.org/licenses/LICENSE-2.0
0734f81384d5f2528bb119f89d135043a280d5b2minfrin *
0734f81384d5f2528bb119f89d135043a280d5b2minfrin * Unless required by applicable law or agreed to in writing, software
0734f81384d5f2528bb119f89d135043a280d5b2minfrin * distributed under the License is distributed on an "AS IS" BASIS,
0734f81384d5f2528bb119f89d135043a280d5b2minfrin * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
0734f81384d5f2528bb119f89d135043a280d5b2minfrin * See the License for the specific language governing permissions and
0734f81384d5f2528bb119f89d135043a280d5b2minfrin * limitations under the License.
0734f81384d5f2528bb119f89d135043a280d5b2minfrin */
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrin/* Load balancer module for Apache proxy */
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrin#include "mod_proxy.h"
0734f81384d5f2528bb119f89d135043a280d5b2minfrin#include "scoreboard.h"
0734f81384d5f2528bb119f89d135043a280d5b2minfrin#include "ap_mpm.h"
0734f81384d5f2528bb119f89d135043a280d5b2minfrin#include "apr_version.h"
0734f81384d5f2528bb119f89d135043a280d5b2minfrin#include "apr_hooks.h"
0734f81384d5f2528bb119f89d135043a280d5b2minfrin#include "apr_date.h"
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrinstatic const char *balancer_mutex_type = "proxy-balancer-shm";
0734f81384d5f2528bb119f89d135043a280d5b2minfrinap_slotmem_provider_t *storage = NULL;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrinmodule AP_MODULE_DECLARE_DATA proxy_balancer_module;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrin/*
0734f81384d5f2528bb119f89d135043a280d5b2minfrin * Register our mutex type before the config is read so we
0734f81384d5f2528bb119f89d135043a280d5b2minfrin * can adjust the mutex settings using the Mutex directive.
0734f81384d5f2528bb119f89d135043a280d5b2minfrin */
0734f81384d5f2528bb119f89d135043a280d5b2minfrinstatic int balancer_pre_config(apr_pool_t *pconf, apr_pool_t *plog,
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                               apr_pool_t *ptemp)
0734f81384d5f2528bb119f89d135043a280d5b2minfrin{
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    apr_status_t rv;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    rv = ap_mutex_register(pconf, balancer_mutex_type, NULL,
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                               APR_LOCK_DEFAULT, 0);
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    if (rv != APR_SUCCESS) {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        return rv;
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh    }
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh    return OK;
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh}
1f1b6bf13313fdd14a45e52e553d3ff28689b717coar
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh#if 0
d84dc356814b255affe3abe2ad93ce17f98e632chumbedoohextern void proxy_update_members(proxy_balancer **balancer, request_rec *r,
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh                                 proxy_server_conf *conf);
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh#endif
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh
d84dc356814b255affe3abe2ad93ce17f98e632chumbedoohstatic int proxy_balancer_canon(request_rec *r, char *url)
1f1b6bf13313fdd14a45e52e553d3ff28689b717coar{
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh    char *host, *path;
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh    char *search = NULL;
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh    const char *err;
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh    apr_port_t port = 0;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    /* TODO: offset of BALANCER_PREFIX ?? */
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    if (strncasecmp(url, "balancer:", 9) == 0) {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        url += 9;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    }
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    else {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        return DECLINED;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    }
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, r->server,
0734f81384d5f2528bb119f89d135043a280d5b2minfrin             "proxy: BALANCER: canonicalising URL %s", url);
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    /* do syntatic check.
04e37a05e8fe2c057cfcc546f382d99fa79894c0gryzor     * We break the URL into host, port, path, search
0734f81384d5f2528bb119f89d135043a280d5b2minfrin     */
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    err = ap_proxy_canon_netloc(r->pool, &url, NULL, NULL, &host, &port);
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    if (err) {
9da97ff0bac3a0ff56a9cdebe6e5ab563636aa86jailletc        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                      "error parsing URL %s: %s",
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                      url, err);
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        return HTTP_BAD_REQUEST;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    }
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    /*
0734f81384d5f2528bb119f89d135043a280d5b2minfrin     * now parse path/search args, according to rfc1738:
0734f81384d5f2528bb119f89d135043a280d5b2minfrin     * process the path. With proxy-noncanon set (by
0734f81384d5f2528bb119f89d135043a280d5b2minfrin     * mod_proxy) we use the raw, unparsed uri
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh     */
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    if (apr_table_get(r->notes, "proxy-nocanon")) {
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh        path = url;   /* this is the raw path */
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    }
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    else {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        path = ap_proxy_canonenc(r->pool, url, strlen(url), enc_path, 0,
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                                 r->proxyreq);
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        search = r->args;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    }
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    if (path == NULL)
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        return HTTP_BAD_REQUEST;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    r->filename = apr_pstrcat(r->pool, "proxy:", BALANCER_PREFIX, host,
0734f81384d5f2528bb119f89d135043a280d5b2minfrin            "/", path, (search) ? "?" : "", (search) ? search : "", NULL);
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    r->path_info = apr_pstrcat(r->pool, "/", path, NULL);
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
9da97ff0bac3a0ff56a9cdebe6e5ab563636aa86jailletc    return OK;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin}
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrinstatic void init_balancer_members(apr_pool_t *p, server_rec *s,
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                                 proxy_balancer *balancer)
0734f81384d5f2528bb119f89d135043a280d5b2minfrin{
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    int i;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    proxy_worker **workers;
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    workers = (proxy_worker **)balancer->workers->elts;
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    for (i = 0; i < balancer->workers->nelts; i++) {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        int worker_is_initialized;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        proxy_worker *worker = *workers;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                     "Looking at %s -> %s initialized?", balancer->name, worker->s->name);
f8080c631d40d9f23da18c91116ca59d8d5468f6covener        worker_is_initialized = PROXY_WORKER_IS_INITIALIZED(worker);
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        if (!worker_is_initialized) {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin            ap_proxy_initialize_worker(worker, s, p);
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        }
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        ++workers;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    }
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    /* Set default number of attempts to the number of
0734f81384d5f2528bb119f89d135043a280d5b2minfrin     * workers.
9da97ff0bac3a0ff56a9cdebe6e5ab563636aa86jailletc     */
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    if (!balancer->s->max_attempts_set && balancer->workers->nelts > 1) {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        balancer->s->max_attempts = balancer->workers->nelts - 1;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        balancer->s->max_attempts_set = 1;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    }
0734f81384d5f2528bb119f89d135043a280d5b2minfrin}
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrin/* Retrieve the parameter with the given name
0734f81384d5f2528bb119f89d135043a280d5b2minfrin * Something like 'JSESSIONID=12345...N'
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh */
0734f81384d5f2528bb119f89d135043a280d5b2minfrinstatic char *get_path_param(apr_pool_t *pool, char *url,
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh                            const char *name, int scolon_sep)
0734f81384d5f2528bb119f89d135043a280d5b2minfrin{
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    char *path = NULL;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    char *pathdelims = "?&";
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    if (scolon_sep) {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        pathdelims = ";?&";
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    }
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    for (path = strstr(url, name); path; path = strstr(path + 1, name)) {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        path += strlen(name);
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        if (*path == '=') {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin            /*
0734f81384d5f2528bb119f89d135043a280d5b2minfrin             * Session path was found, get it's value
0734f81384d5f2528bb119f89d135043a280d5b2minfrin             */
0734f81384d5f2528bb119f89d135043a280d5b2minfrin            ++path;
9da97ff0bac3a0ff56a9cdebe6e5ab563636aa86jailletc            if (*path) {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                char *q;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                path = apr_strtok(apr_pstrdup(pool, path), pathdelims, &q);
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                return path;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin            }
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        }
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    }
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    return NULL;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin}
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrinstatic char *get_cookie_param(request_rec *r, const char *name)
0734f81384d5f2528bb119f89d135043a280d5b2minfrin{
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    const char *cookies;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    const char *start_cookie;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh    if ((cookies = apr_table_get(r->headers_in, "Cookie"))) {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        for (start_cookie = ap_strstr_c(cookies, name); start_cookie;
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh             start_cookie = ap_strstr_c(start_cookie + 1, name)) {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin            if (start_cookie == cookies ||
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                start_cookie[-1] == ';' ||
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                start_cookie[-1] == ',' ||
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                isspace(start_cookie[-1])) {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                start_cookie += strlen(name);
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                while(*start_cookie && isspace(*start_cookie))
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                    ++start_cookie;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                if (*start_cookie++ == '=' && *start_cookie) {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                    /*
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                     * Session cookie was found, get it's value
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                     */
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                    char *end_cookie, *cookie;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                    cookie = apr_pstrdup(r->pool, start_cookie);
9da97ff0bac3a0ff56a9cdebe6e5ab563636aa86jailletc                    if ((end_cookie = strchr(cookie, ';')) != NULL)
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                        *end_cookie = '\0';
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                    if((end_cookie = strchr(cookie, ',')) != NULL)
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                        *end_cookie = '\0';
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                    return cookie;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                }
0734f81384d5f2528bb119f89d135043a280d5b2minfrin            }
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        }
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    }
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    return NULL;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin}
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrin/* Find the worker that has the 'route' defined
0734f81384d5f2528bb119f89d135043a280d5b2minfrin */
d84dc356814b255affe3abe2ad93ce17f98e632chumbedoohstatic proxy_worker *find_route_worker(proxy_balancer *balancer,
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                                       const char *route, request_rec *r)
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh{
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    int i;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    int checking_standby;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    int checked_standby;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    proxy_worker **workers;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    checking_standby = checked_standby = 0;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin    while (!checked_standby) {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        workers = (proxy_worker **)balancer->workers->elts;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin        for (i = 0; i < balancer->workers->nelts; i++, workers++) {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin            proxy_worker *worker = *workers;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin            if ( (checking_standby ? !PROXY_WORKER_IS_STANDBY(worker) : PROXY_WORKER_IS_STANDBY(worker)) )
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                continue;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin            if (*(worker->s->route) && strcmp(worker->s->route, route) == 0) {
9da97ff0bac3a0ff56a9cdebe6e5ab563636aa86jailletc                if (worker && PROXY_WORKER_IS_USABLE(worker)) {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                    return worker;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                } else {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                    /*
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                     * If the worker is in error state run
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                     * retry on that worker. It will be marked as
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                     * operational if the retry timeout is elapsed.
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                     * The worker might still be unusable, but we try
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                     * anyway.
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                     */
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                    ap_proxy_retry_worker("BALANCER", worker, r->server);
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                    if (PROXY_WORKER_IS_USABLE(worker)) {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                            return worker;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                    } else {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                        /*
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                         * We have a worker that is unusable.
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                         * It can be in error or disabled, but in case
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                         * it has a redirection set use that redirection worker.
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh                         * This enables to safely remove the member from the
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                         * balancer. Of course you will need some kind of
d84dc356814b255affe3abe2ad93ce17f98e632chumbedooh                         * session replication between those two remote.
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                         */
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                        if (*worker->s->redirect) {
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                            proxy_worker *rworker = NULL;
0734f81384d5f2528bb119f89d135043a280d5b2minfrin                            rworker = find_route_worker(balancer, worker->s->redirect, r);
                            /* Check if the redirect worker is usable */
                            if (rworker && !PROXY_WORKER_IS_USABLE(rworker)) {
                                /*
                                 * If the worker is in error state run
                                 * retry on that worker. It will be marked as
                                 * operational if the retry timeout is elapsed.
                                 * The worker might still be unusable, but we try
                                 * anyway.
                                 */
                                ap_proxy_retry_worker("BALANCER", rworker, r->server);
                            }
                            if (rworker && PROXY_WORKER_IS_USABLE(rworker))
                                return rworker;
                        }
                    }
                }
            }
        }
        checked_standby = checking_standby++;
    }
    return NULL;
}

static proxy_worker *find_session_route(proxy_balancer *balancer,
                                        request_rec *r,
                                        char **route,
                                        const char **sticky_used,
                                        char **url)
{
    proxy_worker *worker = NULL;

    if (!*balancer->s->sticky)
        return NULL;
    /* Try to find the sticky route inside url */
    *route = get_path_param(r->pool, *url, balancer->s->sticky_path, balancer->s->scolonsep);
    if (*route) {
        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                     "proxy: BALANCER: Found value %s for "
                     "stickysession %s", *route, balancer->s->sticky_path);
        *sticky_used =  balancer->s->sticky_path;
    }
    else {
        *route = get_cookie_param(r, balancer->s->sticky);
        if (*route) {
            *sticky_used =  balancer->s->sticky;
            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                         "proxy: BALANCER: Found value %s for "
                         "stickysession %s", *route, balancer->s->sticky);
        }
    }
    /*
     * If we found a value for sticksession, find the first '.' within.
     * Everything after '.' (if present) is our route.
     */
    if ((*route) && ((*route = strchr(*route, '.')) != NULL ))
        (*route)++;
    if ((*route) && (**route)) {
        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                                  "proxy: BALANCER: Found route %s", *route);
        /* We have a route in path or in cookie
         * Find the worker that has this route defined.
         */
        worker = find_route_worker(balancer, *route, r);
        if (worker && strcmp(*route, worker->s->route)) {
            /*
             * Notice that the route of the worker chosen is different from
             * the route supplied by the client.
             */
            apr_table_setn(r->subprocess_env, "BALANCER_ROUTE_CHANGED", "1");
            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                         "proxy: BALANCER: Route changed from %s to %s",
                         *route, worker->s->route);
        }
        return worker;
    }
    else
        return NULL;
}

static proxy_worker *find_best_worker(proxy_balancer *balancer,
                                      request_rec *r)
{
    proxy_worker *candidate = NULL;
    apr_status_t rv;

    if ((rv = PROXY_THREAD_LOCK(balancer)) != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
        "proxy: BALANCER: (%s). Lock failed for find_best_worker()", balancer->name);
        return NULL;
    }

    candidate = (*balancer->lbmethod->finder)(balancer, r);

    if (candidate)
        candidate->s->elected++;

    if ((rv = PROXY_THREAD_UNLOCK(balancer)) != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
        "proxy: BALANCER: (%s). Unlock failed for find_best_worker()", balancer->name);
    }

    if (candidate == NULL) {
        /* All the workers are in error state or disabled.
         * If the balancer has a timeout sleep for a while
         * and try again to find the worker. The chances are
         * that some other thread will release a connection.
         * By default the timeout is not set, and the server
         * returns SERVER_BUSY.
         */
        if (balancer->s->timeout) {
            /* XXX: This can perhaps be build using some
             * smarter mechanism, like tread_cond.
             * But since the statuses can came from
             * different childs, use the provided algo.
             */
            apr_interval_time_t timeout = balancer->s->timeout;
            apr_interval_time_t step, tval = 0;
            /* Set the timeout to 0 so that we don't
             * end in infinite loop
             */
            balancer->s->timeout = 0;
            step = timeout / 100;
            while (tval < timeout) {
                apr_sleep(step);
                /* Try again */
                if ((candidate = find_best_worker(balancer, r)))
                    break;
                tval += step;
            }
            /* restore the timeout */
            balancer->s->timeout = timeout;
        }
    }

    return candidate;

}

static int rewrite_url(request_rec *r, proxy_worker *worker,
                        char **url)
{
    const char *scheme = strstr(*url, "://");
    const char *path = NULL;

    if (scheme)
        path = ap_strchr_c(scheme + 3, '/');

    /* we break the URL into host, port, uri */
    if (!worker) {
        return ap_proxyerror(r, HTTP_BAD_REQUEST, apr_pstrcat(r->pool,
                             "missing worker. URI cannot be parsed: ", *url,
                             NULL));
    }

    *url = apr_pstrcat(r->pool, worker->s->name, path, NULL);

    return OK;
}

static void force_recovery(proxy_balancer *balancer, server_rec *s)
{
    int i;
    int ok = 0;
    proxy_worker **worker;

    worker = (proxy_worker **)balancer->workers->elts;
    for (i = 0; i < balancer->workers->nelts; i++, worker++) {
        if (!((*worker)->s->status & PROXY_WORKER_IN_ERROR)) {
            ok = 1;
            break;
        }
        else {
            /* Try if we can recover */
            ap_proxy_retry_worker("BALANCER", *worker, s);
            if (!((*worker)->s->status & PROXY_WORKER_IN_ERROR)) {
                ok = 1;
                break;
            }
        }
    }
    if (!ok) {
        /* If all workers are in error state force the recovery.
         */
        worker = (proxy_worker **)balancer->workers->elts;
        for (i = 0; i < balancer->workers->nelts; i++, worker++) {
            ++(*worker)->s->retries;
            (*worker)->s->status &= ~PROXY_WORKER_IN_ERROR;
            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
                         "proxy: BALANCER: (%s). Forcing recovery for worker (%s)",
                         balancer->name, (*worker)->s->hostname);
        }
    }
}

static int proxy_balancer_pre_request(proxy_worker **worker,
                                      proxy_balancer **balancer,
                                      request_rec *r,
                                      proxy_server_conf *conf, char **url)
{
    int access_status;
    proxy_worker *runtime;
    char *route = NULL;
    const char *sticky = NULL;
    apr_status_t rv;

    *worker = NULL;
    /* Step 1: check if the url is for us
     * The url we can handle starts with 'balancer://'
     * If balancer is already provided skip the search
     * for balancer, because this is failover attempt.
     */
    if (!*balancer &&
        !(*balancer = ap_proxy_get_balancer(r->pool, conf, *url)))
        return DECLINED;

    /* Step 2: Lock the LoadBalancer
     * XXX: perhaps we need the process lock here
     */
    if ((rv = PROXY_THREAD_LOCK(*balancer)) != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
                     "proxy: BALANCER: (%s). Lock failed for pre_request",
                     (*balancer)->name);
        return DECLINED;
    }

    /* Step 3: force recovery */
    force_recovery(*balancer, r->server);

    /* Step 3.5: Update member list for the balancer */
    /* TODO: Implement as provider! */
    ap_proxy_sync_balancer(*balancer, r->server, conf);

    /* Step 4: find the session route */
    runtime = find_session_route(*balancer, r, &route, &sticky, url);
    if (runtime) {
        if ((*balancer)->lbmethod && (*balancer)->lbmethod->updatelbstatus) {
            /* Call the LB implementation */
            (*balancer)->lbmethod->updatelbstatus(*balancer, runtime, r->server);
        }
        else { /* Use the default one */
            int i, total_factor = 0;
            proxy_worker **workers;
            /* We have a sticky load balancer
             * Update the workers status
             * so that even session routes get
             * into account.
             */
            workers = (proxy_worker **)(*balancer)->workers->elts;
            for (i = 0; i < (*balancer)->workers->nelts; i++) {
                /* Take into calculation only the workers that are
                 * not in error state or not disabled.
                 */
                if (PROXY_WORKER_IS_USABLE(*workers)) {
                    (*workers)->s->lbstatus += (*workers)->s->lbfactor;
                    total_factor += (*workers)->s->lbfactor;
                }
                workers++;
            }
            runtime->s->lbstatus -= total_factor;
        }
        runtime->s->elected++;

        *worker = runtime;
    }
    else if (route && (*balancer)->s->sticky_force) {
        int i, member_of = 0;
        proxy_worker **workers;
        /*
         * We have a route provided that doesn't match the
         * balancer name. See if the provider route is the
         * member of the same balancer in which case return 503
         */
        workers = (proxy_worker **)(*balancer)->workers->elts;
        for (i = 0; i < (*balancer)->workers->nelts; i++) {
            if (*((*workers)->s->route) && strcmp((*workers)->s->route, route) == 0) {
                member_of = 1;
                break;
            }
            workers++;
        }
        if (member_of) {
            ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
                         "proxy: BALANCER: (%s). All workers are in error state for route (%s)",
                         (*balancer)->name, route);
            if ((rv = PROXY_THREAD_UNLOCK(*balancer)) != APR_SUCCESS) {
                ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
                             "proxy: BALANCER: (%s). Unlock failed for pre_request",
                             (*balancer)->name);
            }
            return HTTP_SERVICE_UNAVAILABLE;
        }
    }

    if ((rv = PROXY_THREAD_UNLOCK(*balancer)) != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
                     "proxy: BALANCER: (%s). Unlock failed for pre_request",
                     (*balancer)->name);
    }
    if (!*worker) {
        runtime = find_best_worker(*balancer, r);
        if (!runtime) {
            if ((*balancer)->workers->nelts) {
                ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
                            "proxy: BALANCER: (%s). All workers are in error state",
                            (*balancer)->name);
            } else {
                ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
                            "proxy: BALANCER: (%s). No workers in balancer",
                            (*balancer)->name);
            }

            return HTTP_SERVICE_UNAVAILABLE;
        }
        if (*(*balancer)->s->sticky && runtime) {
            /*
             * This balancer has sticky sessions and the client either has not
             * supplied any routing information or all workers for this route
             * including possible redirect and hotstandby workers are in error
             * state, but we have found another working worker for this
             * balancer where we can send the request. Thus notice that we have
             * changed the route to the backend.
             */
            apr_table_setn(r->subprocess_env, "BALANCER_ROUTE_CHANGED", "1");
        }
        *worker = runtime;
    }

    (*worker)->s->busy++;

    /* Add balancer/worker info to env. */
    apr_table_setn(r->subprocess_env,
                   "BALANCER_NAME", (*balancer)->name);
    apr_table_setn(r->subprocess_env,
                   "BALANCER_WORKER_NAME", (*worker)->s->name);
    apr_table_setn(r->subprocess_env,
                   "BALANCER_WORKER_ROUTE", (*worker)->s->route);

    /* Rewrite the url from 'balancer://url'
     * to the 'worker_scheme://worker_hostname[:worker_port]/url'
     * This replaces the balancers fictional name with the
     * real hostname of the elected worker.
     */
    access_status = rewrite_url(r, *worker, url);
    /* Add the session route to request notes if present */
    if (route) {
        apr_table_setn(r->notes, "session-sticky", sticky);
        apr_table_setn(r->notes, "session-route", route);

        /* Add session info to env. */
        apr_table_setn(r->subprocess_env,
                       "BALANCER_SESSION_STICKY", sticky);
        apr_table_setn(r->subprocess_env,
                       "BALANCER_SESSION_ROUTE", route);
    }
    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                 "proxy: BALANCER (%s) worker (%s) rewritten to %s",
                 (*balancer)->name, (*worker)->s->name, *url);

    return access_status;
}

static int proxy_balancer_post_request(proxy_worker *worker,
                                       proxy_balancer *balancer,
                                       request_rec *r,
                                       proxy_server_conf *conf)
{

    apr_status_t rv;

    if ((rv = PROXY_THREAD_LOCK(balancer)) != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
            "proxy: BALANCER: (%s). Lock failed for post_request",
            balancer->name);
        return HTTP_INTERNAL_SERVER_ERROR;
    }

    if (!apr_is_empty_array(balancer->errstatuses)) {
        int i;
        for (i = 0; i < balancer->errstatuses->nelts; i++) {
            int val = ((int *)balancer->errstatuses->elts)[i];
            if (r->status == val) {
                ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
                             "proxy: BALANCER: (%s).  Forcing recovery for worker (%s), failonstatus %d",
                             balancer->name, worker->s->name, val);
                worker->s->status |= PROXY_WORKER_IN_ERROR;
                worker->s->error_time = apr_time_now();
                break;
            }
        }
    }

    if ((rv = PROXY_THREAD_UNLOCK(balancer)) != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
            "proxy: BALANCER: (%s). Unlock failed for post_request",
            balancer->name);
    }
    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                 "proxy_balancer_post_request for (%s)", balancer->name);

    if (worker && worker->s->busy)
        worker->s->busy--;

    return OK;

}

static void recalc_factors(proxy_balancer *balancer)
{
    int i;
    proxy_worker **workers;


    /* Recalculate lbfactors */
    workers = (proxy_worker **)balancer->workers->elts;
    /* Special case if there is only one worker it's
     * load factor will always be 1
     */
    if (balancer->workers->nelts == 1) {
        (*workers)->s->lbstatus = (*workers)->s->lbfactor = 1;
        return;
    }
    for (i = 0; i < balancer->workers->nelts; i++) {
        /* Update the status entries */
        workers[i]->s->lbstatus = workers[i]->s->lbfactor;
    }
}

static apr_status_t lock_remove(void *data)
{
    int i;
    proxy_balancer *balancer;
    server_rec *s = data;
    void *sconf = s->module_config;
    proxy_server_conf *conf = (proxy_server_conf *) ap_get_module_config(sconf, &proxy_module);

    balancer = (proxy_balancer *)conf->balancers->elts;
    for (i = 0; i < conf->balancers->nelts; i++, balancer++) {
        if (balancer->gmutex) {
            apr_global_mutex_destroy(balancer->gmutex);
            balancer->gmutex = NULL;
        }
    }
    return(0);
}

/* post_config hook: */
static int balancer_post_config(apr_pool_t *pconf, apr_pool_t *plog,
                         apr_pool_t *ptemp, server_rec *s)
{
    apr_status_t rv;
    void *sconf = s->module_config;
    proxy_server_conf *conf = (proxy_server_conf *) ap_get_module_config(sconf, &proxy_module);
    ap_slotmem_instance_t *new = NULL;
    apr_time_t tstamp;

    /* balancer_post_config() will be called twice during startup.  So, don't
     * set up the static data the 1st time through. */
    if (ap_state_query(AP_SQ_MAIN_STATE) == AP_SQ_MS_CREATE_PRE_CONFIG)
        return OK;

    /*
     * Get slotmem setups
     */
    storage = ap_lookup_provider(AP_SLOTMEM_PROVIDER_GROUP, "shared", "0");
    if (!storage) {
        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_EMERG, 0, s,
                     "ap_lookup_provider %s failed", AP_SLOTMEM_PROVIDER_GROUP);
        return !OK;
    }

    tstamp = apr_time_now();
    /*
     * Go thru each Vhost and create the shared mem slotmem for
     * each balancer's workers
     */
    while (s) {
        int i,j;
        proxy_balancer *balancer;
        sconf = s->module_config;
        conf = (proxy_server_conf *)ap_get_module_config(sconf, &proxy_module);

        if (conf->balancers->nelts) {
            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, "Doing balancers create: %d, %d",
                         (int)ALIGNED_PROXY_BALANCER_SHARED_SIZE,
                         (int)conf->balancers->nelts);

            rv = storage->create(&new, conf->id,
                                 ALIGNED_PROXY_BALANCER_SHARED_SIZE,
                                 conf->balancers->nelts, AP_SLOTMEM_TYPE_PREGRAB, pconf);
            if (rv != APR_SUCCESS) {
                ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, "balancer slotmem_create failed");
                return !OK;
            }
            conf->slot = new;
        }
        conf->storage = storage;

        /* Initialize shared scoreboard data */
        balancer = (proxy_balancer *)conf->balancers->elts;
        for (i = 0; i < conf->balancers->nelts; i++, balancer++) {
            proxy_worker **workers;
            proxy_worker *worker;
            proxy_balancer_shared *bshm;
            unsigned int index;

            balancer->max_workers = balancer->workers->nelts + balancer->growth;
            /* no need for the 'balancer://' prefix */
            ap_pstr2_alnum(pconf, balancer->name + sizeof(BALANCER_PREFIX) - 1,
                           &balancer->sname);
            balancer->sname = apr_pstrcat(pconf, conf->id, "_", balancer->sname, NULL);

            /* Create global mutex */
            rv = ap_global_mutex_create(&(balancer->gmutex), NULL, balancer_mutex_type,
                                        balancer->sname, s, pconf, 0);
            if (rv != APR_SUCCESS || !balancer->gmutex) {
                ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s,
                             "mutex creation of %s : %s failed", balancer_mutex_type,
                             balancer->sname);
                return HTTP_INTERNAL_SERVER_ERROR;
            }

            apr_pool_cleanup_register(pconf, (void *)s, lock_remove,
                                      apr_pool_cleanup_null);

            /* setup shm for balancers */
            if ((rv = storage->grab(conf->slot, &index)) != APR_SUCCESS) {
                ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, "balancer slotmem_grab failed");
                return !OK;

            }
            if ((rv = storage->dptr(conf->slot, index, (void *)&bshm)) != APR_SUCCESS) {
                ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, "balancer slotmem_dptr failed");
                return !OK;
            }
            if ((rv = ap_proxy_share_balancer(balancer, bshm, index)) != APR_SUCCESS) {
                ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, "Cannot share balancer");
                return !OK;
            }

            /* create slotmem slots for workers */
            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, "Doing workers create: %s (%s), %d, %d",
                         balancer->name, balancer->sname,
                         (int)ALIGNED_PROXY_WORKER_SHARED_SIZE,
                         (int)balancer->max_workers);

            rv = storage->create(&new, balancer->sname,
                                 ALIGNED_PROXY_WORKER_SHARED_SIZE,
                                 balancer->max_workers, AP_SLOTMEM_TYPE_PREGRAB, pconf);
            if (rv != APR_SUCCESS) {
                ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, "worker slotmem_create failed");
                return !OK;
            }
            balancer->slot = new;
            balancer->storage = storage;

            /* sync all timestamps */
            balancer->wupdated = balancer->s->wupdated = tstamp;

            /* now go thru each worker */
            workers = (proxy_worker **)balancer->workers->elts;
            for (j = 0; j < balancer->workers->nelts; j++, workers++) {
                proxy_worker_shared *shm;

                worker = *workers;
                if ((rv = storage->grab(balancer->slot, &index)) != APR_SUCCESS) {
                    ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, "worker slotmem_grab failed");
                    return !OK;

                }
                if ((rv = storage->dptr(balancer->slot, index, (void *)&shm)) != APR_SUCCESS) {
                    ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, "worker slotmem_dptr failed");
                    return !OK;
                }
                if ((rv = ap_proxy_share_worker(worker, shm, index)) != APR_SUCCESS) {
                    ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, "Cannot share worker");
                    return !OK;
                }
                worker->s->updated = tstamp;
            }
        }
        s = s->next;
    }

    return OK;
}

static void create_radio(const char *name, unsigned int flag, request_rec *r)
{
    ap_rvputs(r, "<td>On <input name='", name, "' id='", name, "' value='1' type=radio", NULL);
    if (flag)
        ap_rputs(" checked", r);
    ap_rvputs(r, "> <br/> Off <input name='", name, "' id='", name, "' value='0' type=radio", NULL);
    if (!flag)
        ap_rputs(" checked", r);
    ap_rputs("></td>\n", r);
}

static void push2table(const char *input, apr_table_t *params,
                       const char *allowed[], apr_pool_t *p)
{
    char *args;
    char *tok, *val;
    char *key;

    if (input == NULL) {
        return;
    }
    args = apr_pstrdup(p, input);

    key = apr_strtok(args, "&", &tok);
    while (key) {
        val = strchr(key, '=');
        if (val) {
            *val++ = '\0';
        }
        else {
            val = "";
        }
        ap_unescape_url(key);
        ap_unescape_url(val);
        if (allowed == NULL) { /* allow all */
            apr_table_set(params, key, val);
        }
        else {
            const char *ok = *allowed;
            while (ok) {
                if (strcmp(ok, key) == 0) {
                    apr_table_set(params, key, val);
                    break;
                }
                ok++;
            }
        }
        key = apr_strtok(NULL, "&", &tok);
    }
}

/* Manages the loadfactors and member status
 *   The balancer, worker and nonce are obtained from
 *   the request args (?b=...&w=...&nonce=....).
 *   All other params are pulled from any POST
 *   data that exists.
 * TODO:
 *   /.../<whatever>/balancer/worker/nonce
 */
static int balancer_handler(request_rec *r)
{
    void *sconf;
    proxy_server_conf *conf;
    proxy_balancer *balancer, *bsel = NULL;
    proxy_worker *worker, *wsel = NULL;
    proxy_worker **workers = NULL;
    apr_table_t *params;
    int i, n;
    int ok2change = 1;
    const char *name;
    const char *action;
    apr_status_t rv;

    /* is this for us? */
    if (strcmp(r->handler, "balancer-manager")) {
        return DECLINED;
    }

    r->allowed = 0
    | (AP_METHOD_BIT << M_GET)
    | (AP_METHOD_BIT << M_POST);
    if ((r->method_number != M_GET) && (r->method_number != M_POST)) {
        return DECLINED;
    }

    sconf = r->server->module_config;
    conf = (proxy_server_conf *) ap_get_module_config(sconf, &proxy_module);
    params = apr_table_make(r->pool, 10);

    balancer = (proxy_balancer *)conf->balancers->elts;
    for (i = 0; i < conf->balancers->nelts; i++, balancer++) {
        if ((rv = PROXY_THREAD_LOCK(balancer)) != APR_SUCCESS) {
            ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
                         "proxy: BALANCER: (%s). Lock failed for balancer_handler",
                         balancer->name);
        }
        ap_proxy_sync_balancer(balancer, r->server, conf);
        if ((rv = PROXY_THREAD_UNLOCK(balancer)) != APR_SUCCESS) {
            ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
                         "proxy: BALANCER: (%s). Unlock failed for balancer_handler",
                         balancer->name);
        }
    }

    if (r->args && (r->method_number == M_GET)) {
        const char *allowed[] = { "w", "b", "nonce", NULL };
        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, "parsing r->args");

        push2table(r->args, params, allowed, r->pool);
    }
    if (r->method_number == M_POST) {
        apr_bucket_brigade *ib;
        apr_size_t len = 1024;
        char *buf = apr_pcalloc(r->pool, len+1);

        ib = apr_brigade_create(r->connection->pool, r->connection->bucket_alloc);
        rv = ap_get_brigade(r->input_filters, ib, AP_MODE_READBYTES,
                                APR_BLOCK_READ, len);
        if (rv != APR_SUCCESS) {
            return HTTP_INTERNAL_SERVER_ERROR;
        }
        apr_brigade_flatten(ib, buf, &len);
        buf[len] = '\0';
        push2table(buf, params, NULL, r->pool);
    }
    if ((name = apr_table_get(params, "b")))
        bsel = ap_proxy_get_balancer(r->pool, conf,
            apr_pstrcat(r->pool, BALANCER_PREFIX, name, NULL));

    if ((name = apr_table_get(params, "w"))) {
        wsel = ap_proxy_get_worker(r->pool, bsel, conf, name);
    }


    /* Check that the supplied nonce matches this server's nonce;
     * otherwise ignore all parameters, to prevent a CSRF attack. */
    if (!bsel ||
        (*bsel->s->nonce &&
         (
          (name = apr_table_get(params, "nonce")) == NULL ||
          strcmp(bsel->s->nonce, name) != 0
         )
        )
       ) {
        apr_table_clear(params);
        ok2change = 0;
    }

    /* First set the params */
    if (wsel && ok2change) {
        const char *val;
        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, "settings worker params");

        if ((val = apr_table_get(params, "w_lf"))) {
            int ival = atoi(val);
            if (ival >= 1 && ival <= 100) {
                wsel->s->lbfactor = ival;
                if (bsel)
                    recalc_factors(bsel);
            }
        }
        if ((val = apr_table_get(params, "w_wr"))) {
            if (strlen(val) && strlen(val) < sizeof(wsel->s->route))
                strcpy(wsel->s->route, val);
            else
                *wsel->s->route = '\0';
        }
        if ((val = apr_table_get(params, "w_rr"))) {
            if (strlen(val) && strlen(val) < sizeof(wsel->s->redirect))
                strcpy(wsel->s->redirect, val);
            else
                *wsel->s->redirect = '\0';
        }
        if ((val = apr_table_get(params, "w_status_I"))) {
            ap_proxy_set_wstatus('I', atoi(val), wsel);
        }
        if ((val = apr_table_get(params, "w_status_N"))) {
            ap_proxy_set_wstatus('N', atoi(val), wsel);
        }
        if ((val = apr_table_get(params, "w_status_D"))) {
            ap_proxy_set_wstatus('D', atoi(val), wsel);
        }
        if ((val = apr_table_get(params, "w_status_H"))) {
            ap_proxy_set_wstatus('H', atoi(val), wsel);
        }
        if ((val = apr_table_get(params, "w_ls"))) {
            int ival = atoi(val);
            if (ival >= 0 && ival <= 99) {
                wsel->s->lbset = ival;
             }
        }

    }

    if (bsel && ok2change) {
        const char *val;
        int ival;
        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, "settings balancer params");
        if ((val = apr_table_get(params, "b_lbm"))) {
            if (strlen(val) < (sizeof(bsel->s->lbpname)-1)) {
                proxy_balancer_method *lbmethod;
                lbmethod = ap_lookup_provider(PROXY_LBMETHOD, bsel->s->lbpname, "0");
                if (lbmethod) {
                    PROXY_STRNCPY(bsel->s->lbpname, val);
                    bsel->lbmethod = lbmethod;
                    bsel->s->wupdated = apr_time_now();
                }
            }
        }
        if ((val = apr_table_get(params, "b_tmo"))) {
            ival = atoi(val);
            if (ival >= 0 && ival <= 7200) { /* 2 hrs enuff? */
                bsel->s->timeout = apr_time_from_sec(ival);
            }
        }
        if ((val = apr_table_get(params, "b_max"))) {
            ival = atoi(val);
            if (ival >= 0 && ival <= 99) {
                bsel->s->max_attempts = ival;
            }
        }
        if ((val = apr_table_get(params, "b_sforce"))) {
            ival = atoi(val);
            bsel->s->sticky_force = (ival != 0);
        }
        if ((val = apr_table_get(params, "b_ss")) && *val) {
            if (strlen(val) < (sizeof(bsel->s->sticky_path)-1)) {
                if (*val == '-' && *(val+1) == '\0')
                    *bsel->s->sticky_path = *bsel->s->sticky = '\0';
                else {
                    char *path;
                    PROXY_STRNCPY(bsel->s->sticky_path, val);
                    PROXY_STRNCPY(bsel->s->sticky, val);

                    if ((path = strchr((char *)bsel->s->sticky, '|'))) {
                        *path++ = '\0';
                        PROXY_STRNCPY(bsel->s->sticky_path, path);
                    }
                }
            }
        }
        if ((val = apr_table_get(params, "b_wyes")) &&
            (*val == '1' && *(val+1) == '\0') &&
            (val = apr_table_get(params, "b_nwrkr"))) {
            char *ret;
            proxy_worker *nworker;
            nworker = ap_proxy_get_worker(conf->pool, bsel, conf, val);
            if (!nworker && storage->num_free_slots(bsel->slot)) {
                if ((rv = PROXY_GLOBAL_LOCK(bsel)) != APR_SUCCESS) {
                    ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
                                 "proxy: BALANCER: (%s). Lock failed for adding worker",
                                 bsel->name);
                }
                ret = ap_proxy_define_worker(conf->pool, &nworker, bsel, conf, val, 0);
                if (!ret) {
                    unsigned int index;
                    proxy_worker_shared *shm;
                    PROXY_COPY_CONF_PARAMS(nworker, conf);
                    if ((rv = storage->grab(bsel->slot, &index)) != APR_SUCCESS) {
                        ap_log_error(APLOG_MARK, APLOG_EMERG, rv, r->server, "worker slotmem_grab failed");
                        if ((rv = PROXY_GLOBAL_UNLOCK(bsel)) != APR_SUCCESS) {
                            ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
                                         "proxy: BALANCER: (%s). Unlock failed for adding worker",
                                         bsel->name);
                        }
                        return HTTP_BAD_REQUEST;
                    }
                    if ((rv = storage->dptr(bsel->slot, index, (void *)&shm)) != APR_SUCCESS) {
                        ap_log_error(APLOG_MARK, APLOG_EMERG, rv, r->server, "worker slotmem_dptr failed");
                        if ((rv = PROXY_GLOBAL_UNLOCK(bsel)) != APR_SUCCESS) {
                            ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
                                         "proxy: BALANCER: (%s). Unlock failed for adding worker",
                                         bsel->name);
                        }
                        return HTTP_BAD_REQUEST;
                    }
                    if ((rv = ap_proxy_share_worker(nworker, shm, index)) != APR_SUCCESS) {
                        ap_log_error(APLOG_MARK, APLOG_EMERG, rv, r->server, "Cannot share worker");
                        if ((rv = PROXY_GLOBAL_UNLOCK(bsel)) != APR_SUCCESS) {
                            ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
                                         "proxy: BALANCER: (%s). Unlock failed for adding worker",
                                         bsel->name);
                        }
                        return HTTP_BAD_REQUEST;
                    }
                    if ((rv = ap_proxy_initialize_worker(nworker, r->server, conf->pool)) != APR_SUCCESS) {
                        ap_log_error(APLOG_MARK, APLOG_EMERG, rv, r->server, "Cannot init worker");
                        if ((rv = PROXY_GLOBAL_UNLOCK(bsel)) != APR_SUCCESS) {
                            ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
                                         "proxy: BALANCER: (%s). Unlock failed for adding worker",
                                         bsel->name);
                        }
                        return HTTP_BAD_REQUEST;
                    }
                    /* sync all timestamps */
                    bsel->wupdated = bsel->s->wupdated = nworker->s->updated = apr_time_now();
                    /* by default, all new workers are disabled */
                    ap_proxy_set_wstatus('D', 1, nworker);
                }
                if ((rv = PROXY_GLOBAL_UNLOCK(bsel)) != APR_SUCCESS) {
                    ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
                                 "proxy: BALANCER: (%s). Unlock failed for adding worker",
                                 bsel->name);
                }
            }

        }

    }

    action = ap_construct_url(r->pool, r->uri, r);
    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server, "genning page");

    if (apr_table_get(params, "xml")) {
        ap_set_content_type(r, "text/xml");
        ap_rputs("<?xml version='1.0' encoding='UTF-8' ?>\n", r);
        ap_rputs("<httpd:manager xmlns:httpd='http://httpd.apache.org'>\n", r);
        ap_rputs("  <httpd:balancers>\n", r);
        balancer = (proxy_balancer *)conf->balancers->elts;
        for (i = 0; i < conf->balancers->nelts; i++) {
            ap_rputs("    <httpd:balancer>\n", r);
            ap_rvputs(r, "      <httpd:name>", balancer->name, "</httpd:name>\n", NULL);
            ap_rputs("      <httpd:workers>\n", r);
            workers = (proxy_worker **)balancer->workers->elts;
            for (n = 0; n < balancer->workers->nelts; n++) {
                worker = *workers;
                ap_rputs("        <httpd:worker>\n", r);
                ap_rvputs(r, "          <httpd:scheme>", worker->s->scheme,
                          "</httpd:scheme>\n", NULL);
                ap_rvputs(r, "          <httpd:hostname>", worker->s->hostname,
                          "</httpd:hostname>\n", NULL);
                ap_rprintf(r, "          <httpd:loadfactor>%d</httpd:loadfactor>\n",
                          worker->s->lbfactor);
                ap_rputs("        </httpd:worker>\n", r);
                ++workers;
            }
            ap_rputs("      </httpd:workers>\n", r);
            ap_rputs("    </httpd:balancer>\n", r);
            ++balancer;
        }
        ap_rputs("  </httpd:balancers>\n", r);
        ap_rputs("</httpd:manager>", r);
    }
    else {
        ap_set_content_type(r, "text/html; charset=ISO-8859-1");
        ap_rputs(DOCTYPE_HTML_3_2
                 "<html><head><title>Balancer Manager</title></head>\n", r);
        ap_rputs("<body><h1>Load Balancer Manager for ", r);
        ap_rvputs(r, ap_get_server_name(r), "</h1>\n\n", NULL);
        ap_rvputs(r, "<dl><dt>Server Version: ",
                  ap_get_server_description(), "</dt>\n", NULL);
        ap_rvputs(r, "<dt>Server Built: ",
                  ap_get_server_built(), "\n</dt></dl>\n", NULL);
        balancer = (proxy_balancer *)conf->balancers->elts;
        for (i = 0; i < conf->balancers->nelts; i++) {

            ap_rputs("<hr />\n<h3>LoadBalancer Status for ", r);
            ap_rvputs(r, "<a href='", r->uri, "?b=",
                      balancer->name + sizeof(BALANCER_PREFIX) - 1,
                      "&nonce=", balancer->s->nonce,
                      "'>", NULL);
            ap_rvputs(r, balancer->name, "</a></h3>\n\n", NULL);
            ap_rputs("\n\n<table border='0' style='text-align: left;'><tr>"
                "<th>MaxMembers</th><th>StickySession</th><th>DisableFailover</th><th>Timeout</th><th>FailoverAttempts</th><th>Method</th>"
                "</tr>\n<tr>", r);
            /* the below is a safe cast, since the number of slots total will
             * never be more than max_workers, which is restricted to int */
            ap_rprintf(r, "<td align='center'>%d [%d Used]</td>\n", balancer->max_workers,
                       balancer->max_workers - (int)storage->num_free_slots(balancer->slot));
            if (*balancer->s->sticky) {
                if (strcmp(balancer->s->sticky, balancer->s->sticky_path)) {
                    ap_rvputs(r, "<td align='center'>", balancer->s->sticky, " | ",
                              balancer->s->sticky_path, NULL);
                }
                else {
                    ap_rvputs(r, "<td align='center'>", balancer->s->sticky, NULL);
                }
            }
            else {
                ap_rputs("<td align='center'> (None) ", r);
            }
            ap_rprintf(r, "<td align='center'>%s</td>\n",
                       balancer->s->sticky_force ? "On" : "Off");
            ap_rprintf(r, "</td><td align='center'>%" APR_TIME_T_FMT "</td>",
                apr_time_sec(balancer->s->timeout));
            ap_rprintf(r, "<td align='center'>%d</td>\n", balancer->s->max_attempts);
            ap_rprintf(r, "<td align='center'>%s</td>\n",
                       balancer->s->lbpname);
            ap_rputs("</table>\n<br />", r);
            ap_rputs("\n\n<table border='0' style='text-align: left;'><tr>"
                "<th>Worker URL</th>"
                "<th>Route</th><th>RouteRedir</th>"
                "<th>Factor</th><th>Set</th><th align='center'>Status</th>"
                "<th>Elected</th><th>To</th><th>From</th>"
                "</tr>\n", r);

            workers = (proxy_worker **)balancer->workers->elts;
            for (n = 0; n < balancer->workers->nelts; n++) {
                char fbuf[50];
                worker = *workers;
                ap_rvputs(r, "<tr>\n<td><a href='", r->uri, "?b=",
                          balancer->name + sizeof(BALANCER_PREFIX) - 1, "&w=",
                          ap_escape_uri(r->pool, worker->s->name),
                          "&nonce=", balancer->s->nonce,
                          "'>", NULL);
                ap_rvputs(r, worker->s->name, "</a></td>", NULL);
                ap_rvputs(r, "<td align='center'>", ap_escape_html(r->pool, worker->s->route),
                          NULL);
                ap_rvputs(r, "</td><td align='center'>",
                          ap_escape_html(r->pool, worker->s->redirect), NULL);
                ap_rprintf(r, "</td><td align='center'>%d</td>", worker->s->lbfactor);
                ap_rprintf(r, "<td align='center'>%d</td><td align='center'>", worker->s->lbset);
                ap_rvputs(r, ap_proxy_parse_wstatus(r->pool, worker), NULL);
                ap_rputs("</td>", r);
                ap_rprintf(r, "<td align='center'>%" APR_SIZE_T_FMT "</td><td align='center'>", worker->s->elected);
                ap_rputs(apr_strfsize(worker->s->transferred, fbuf), r);
                ap_rputs("</td><td align='center'>", r);
                ap_rputs(apr_strfsize(worker->s->read, fbuf), r);
                ap_rputs("</td></tr>\n", r);

                ++workers;
            }
            ap_rputs("</table>\n", r);
            ++balancer;
        }
        ap_rputs("<hr />\n", r);
        if (wsel && bsel) {
            ap_rputs("<h3>Edit worker settings for ", r);
            ap_rvputs(r, wsel->s->name, "</h3>\n", NULL);
            ap_rputs("<form method='POST' enctype='application/x-www-form-urlencoded' action='", r);
            ap_rvputs(r, action, "'>\n", NULL);
            ap_rputs("<dl>\n<table><tr><td>Load factor:</td><td><input name='w_lf' id='w_lf' type=text ", r);
            ap_rprintf(r, "value='%d'></td></tr>\n", wsel->s->lbfactor);
            ap_rputs("<tr><td>LB Set:</td><td><input name='w_ls' id='w_ls' type=text ", r);
            ap_rprintf(r, "value='%d'></td></tr>\n", wsel->s->lbset);
            ap_rputs("<tr><td>Route:</td><td><input name='w_wr' id='w_wr' type=text ", r);
            ap_rvputs(r, "value='", ap_escape_html(r->pool, wsel->s->route),
                      NULL);
            ap_rputs("'></td></tr>\n", r);
            ap_rputs("<tr><td>Route Redirect:</td><td><input name='w_rr' id='w_rr' type=text ", r);
            ap_rvputs(r, "value='", ap_escape_html(r->pool, wsel->s->redirect),
                      NULL);
            ap_rputs("'></td></tr>\n", r);
            ap_rputs("<tr><td>Status:</td>", r);
            ap_rputs("<td><table border='1'><tr><th>Ign</th><th>Drn</th><th>Dis</th><th>Stby</th></tr>\n<tr>", r);
            create_radio("w_status_I", (PROXY_WORKER_IGNORE_ERRORS & wsel->s->status), r);
            create_radio("w_status_N", (PROXY_WORKER_DRAIN & wsel->s->status), r);
            create_radio("w_status_D", (PROXY_WORKER_DISABLED & wsel->s->status), r);
            create_radio("w_status_H", (PROXY_WORKER_HOT_STANDBY & wsel->s->status), r);
            ap_rputs("</tr></table>\n", r);
            ap_rputs("<tr><td colspan=2><input type=submit value='Submit'></td></tr>\n", r);
            ap_rvputs(r, "</table>\n<input type=hidden name='w' id='w' ",  NULL);
            ap_rvputs(r, "value='", ap_escape_uri(r->pool, wsel->s->name), "'>\n", NULL);
            ap_rvputs(r, "<input type=hidden name='b' id='b' ", NULL);
            ap_rvputs(r, "value='", bsel->name + sizeof(BALANCER_PREFIX) - 1,
                      "'>\n", NULL);
            ap_rvputs(r, "<input type=hidden name='nonce' id='nonce' value='",
                      bsel->s->nonce, "'>\n", NULL);
            ap_rvputs(r, "</form>\n", NULL);
            ap_rputs("<hr />\n", r);
        } else if (bsel) {
            const apr_array_header_t *provs;
            const ap_list_provider_names_t *pname;
            int i;
            ap_rputs("<h3>Edit balancer settings for ", r);
            ap_rvputs(r, bsel->name, "</h3>\n", NULL);
            ap_rputs("<form method='POST' enctype='application/x-www-form-urlencoded' action='", r);
            ap_rvputs(r, action, "'>\n", NULL);
            ap_rputs("<dl>\n<table>\n", r);
            provs = ap_list_provider_names(r->pool, PROXY_LBMETHOD, "0");
            if (provs) {
                ap_rputs("<tr><td>LBmethod:</td>", r);
                ap_rputs("<td>\n<select name='b_lbm' id='b_lbm'>", r);
                pname = (ap_list_provider_names_t *)provs->elts;
                for (i = 0; i < provs->nelts; i++, pname++) {
                    ap_rvputs(r,"<option value='", pname->provider_name, "'", NULL);
                    if (strcmp(pname->provider_name, bsel->s->lbpname) == 0)
                        ap_rputs(" selected ", r);
                    ap_rvputs(r, ">", pname->provider_name, "\n", NULL);
                }
                ap_rputs("</select>\n</td></tr>\n", r);
            }
            ap_rputs("<tr><td>Timeout:</td><td><input name='b_tmo' id='b_tmo' type=text ", r);
            ap_rprintf(r, "value='%" APR_TIME_T_FMT "'></td></tr>\n", apr_time_sec(bsel->s->timeout));
            ap_rputs("<tr><td>Failover Attempts:</td><td><input name='b_max' id='b_max' type=text ", r);
            ap_rprintf(r, "value='%d'></td></tr>\n", bsel->s->max_attempts);
            ap_rputs("<tr><td>Disable Failover:</td>", r);
            create_radio("b_sforce", bsel->s->sticky_force, r);
            ap_rputs("<tr><td>Sticky Session:</td><td><input name='b_ss' id='b_ss' size=64 type=text ", r);
            if (strcmp(bsel->s->sticky, bsel->s->sticky_path)) {
                ap_rvputs(r, "value ='", bsel->s->sticky, " | ",
                          bsel->s->sticky_path, NULL);
            }
            else {
                ap_rvputs(r, "value ='", bsel->s->sticky, NULL);
            }
            ap_rputs("'>&nbsp;&nbsp;&nbsp;&nbsp;(Use '-' to delete)</td></tr>\n", r);
            if (storage->num_free_slots(bsel->slot) != 0) {
                ap_rputs("<tr><td>Add New Worker:</td><td><input name='b_nwrkr' id='b_nwrkr' size=32 type=text>"
                         "&nbsp;&nbsp;&nbsp;&nbsp;Are you sure? <input name='b_wyes' id='b_wyes' type=checkbox value='1'>"
                         "</td></tr>", r);
            }
            ap_rputs("<tr><td colspan=2><input type=submit value='Submit'></td></tr>\n", r);
            ap_rvputs(r, "</table>\n<input type=hidden name='b' id='b' ", NULL);
            ap_rvputs(r, "value='", bsel->name + sizeof(BALANCER_PREFIX) - 1,
                      "'>\n", NULL);
            ap_rvputs(r, "<input type=hidden name='nonce' id='nonce' value='",
                      bsel->s->nonce, "'>\n", NULL);
            ap_rvputs(r, "</form>\n", NULL);
            ap_rputs("<hr />\n", r);
        }
        ap_rputs(ap_psignature("",r), r);
        ap_rputs("</body></html>\n", r);
        ap_rflush(r);
    }
    return DONE;
}

static void balancer_child_init(apr_pool_t *p, server_rec *s)
{
    while (s) {
        proxy_balancer *balancer;
        int i;
        void *sconf = s->module_config;
        proxy_server_conf *conf = (proxy_server_conf *)ap_get_module_config(sconf, &proxy_module);
        apr_status_t rv;

        if (conf->balancers->nelts) {
            apr_size_t size;
            unsigned int num;
            storage->attach(&(conf->slot), conf->id, &size, &num, p);
            if (!conf->slot) {
                ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_EMERG, 0, s, "slotmem_attach failed");
                exit(1); /* Ugly, but what else? */
            }
        }

        balancer = (proxy_balancer *)conf->balancers->elts;
        for (i = 0; i < conf->balancers->nelts; i++, balancer++) {
            rv = ap_proxy_initialize_balancer(balancer, s, p);

            if (rv != APR_SUCCESS) {
                ap_log_error(APLOG_MARK, APLOG_CRIT, rv, s,
                             "Failed to init balancer %s in child",
                             balancer->name);
                exit(1); /* Ugly, but what else? */
            }
            init_balancer_members(conf->pool, s, balancer);
        }
        s = s->next;
    }

}

static void ap_proxy_balancer_register_hook(apr_pool_t *p)
{
    /* Only the mpm_winnt has child init hook handler.
     * make sure that we are called after the mpm
     * initializes
     */
    static const char *const aszPred[] = { "mpm_winnt.c", "mod_slotmem_shm.c", NULL};
     /* manager handler */
    ap_hook_post_config(balancer_post_config, NULL, NULL, APR_HOOK_MIDDLE);
    ap_hook_pre_config(balancer_pre_config, NULL, NULL, APR_HOOK_MIDDLE);
    ap_hook_handler(balancer_handler, NULL, NULL, APR_HOOK_FIRST);
    ap_hook_child_init(balancer_child_init, aszPred, NULL, APR_HOOK_MIDDLE);
    proxy_hook_pre_request(proxy_balancer_pre_request, NULL, NULL, APR_HOOK_FIRST);
    proxy_hook_post_request(proxy_balancer_post_request, NULL, NULL, APR_HOOK_FIRST);
    proxy_hook_canon_handler(proxy_balancer_canon, NULL, NULL, APR_HOOK_FIRST);
}

AP_DECLARE_MODULE(proxy_balancer) = {
    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 */
    NULL,       /* command apr_table_t */
    ap_proxy_balancer_register_hook /* register hooks */
};