granicus.if.org Git - apache/blob - modules/proxy/mod_proxy_balancer.c

   1 /* Licensed to the Apache Software Foundation (ASF) under one or more
   2  * contributor license agreements.  See the NOTICE file distributed with
   3  * this work for additional information regarding copyright ownership.
   4  * The ASF licenses this file to You under the Apache License, Version 2.0
   5  * (the "License"); you may not use this file except in compliance with
   6  * the License.  You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 /* Load balancer module for Apache proxy */
  18
  19 #include "mod_proxy.h"
  20 #include "scoreboard.h"
  21 #include "ap_mpm.h"
  22 #include "apr_version.h"
  23 #include "apr_hooks.h"
  24 #include "apr_uuid.h"
  25
  26 module AP_MODULE_DECLARE_DATA proxy_balancer_module;
  27
  28 static char balancer_nonce[APR_UUID_FORMATTED_LENGTH + 1];
  29
  30 static int proxy_balancer_canon(request_rec *r, char *url)
  31 {
  32     char *host, *path;
  33     char *search = NULL;
  34     const char *err;
  35     apr_port_t port = 0;
  36
  37     if (strncasecmp(url, "balancer:", 9) == 0) {
  38         url += 9;
  39     }
  40     else {
  41         return DECLINED;
  42     }
  43
  44     ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
  45              "proxy: BALANCER: canonicalising URL %s", url);
  46
  47     /* do syntatic check.
  48      * We break the URL into host, port, path, search
  49      */
  50     err = ap_proxy_canon_netloc(r->pool, &url, NULL, NULL, &host, &port);
  51     if (err) {
  52         ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
  53                       "error parsing URL %s: %s",
  54                       url, err);
  55         return HTTP_BAD_REQUEST;
  56     }
  57     /*
  58      * now parse path/search args, according to rfc1738:
  59      * process the path. With proxy-noncanon set (by
  60      * mod_proxy) we use the raw, unparsed uri
  61      */
  62     if (apr_table_get(r->notes, "proxy-nocanon")) {
  63         path = url;   /* this is the raw path */
  64     }
  65     else {
  66         path = ap_proxy_canonenc(r->pool, url, strlen(url), enc_path, 0,
  67                                  r->proxyreq);
  68         search = r->args;
  69     }
  70     if (path == NULL)
  71         return HTTP_BAD_REQUEST;
  72
  73     r->filename = apr_pstrcat(r->pool, "proxy:balancer://", host,
  74             "/", path, (search) ? "?" : "", (search) ? search : "", NULL);
  75
  76     r->path_info = apr_pstrcat(r->pool, "/", path, NULL);
  77
  78     return OK;
  79 }
  80
  81 static int init_balancer_members(proxy_server_conf *conf, server_rec *s,
  82                                  proxy_balancer *balancer)
  83 {
  84     int i;
  85     proxy_worker **workers;
  86
  87     workers = (proxy_worker **)balancer->workers->elts;
  88
  89     for (i = 0; i < balancer->workers->nelts; i++) {
  90         int worker_is_initialized;
  91         worker_is_initialized = PROXY_WORKER_IS_INITIALIZED(*workers);
  92         if (!worker_is_initialized) {
  93             proxy_worker_stat *slot;
  94             /*
  95              * If the worker is not initialized check whether its scoreboard
  96              * slot is already initialized.
  97              */
  98             slot = (proxy_worker_stat *) ap_get_scoreboard_lb((*workers)->id);
  99             if (slot) {
 100                 worker_is_initialized = slot->status & PROXY_WORKER_INITIALIZED;
 101             }
 102             else {
 103                 worker_is_initialized = 0;
 104             }
 105         }
 106         ap_proxy_initialize_worker_share(conf, *workers, s);
 107         ap_proxy_initialize_worker(*workers, s, conf->pool);
 108         if (!worker_is_initialized) {
 109             /* Set to the original configuration */
 110             (*workers)->s->lbstatus = (*workers)->s->lbfactor =
 111             ((*workers)->lbfactor ? (*workers)->lbfactor : 1);
 112             (*workers)->s->lbset = (*workers)->lbset;
 113         }
 114         ++workers;
 115     }
 116
 117     /* Set default number of attempts to the number of
 118      * workers.
 119      */
 120     if (!balancer->max_attempts_set && balancer->workers->nelts > 1) {
 121         balancer->max_attempts = balancer->workers->nelts - 1;
 122         balancer->max_attempts_set = 1;
 123     }
 124     return 0;
 125 }
 126
 127 /* Retrieve the parameter with the given name
 128  * Something like 'JSESSIONID=12345...N'
 129  */
 130 static char *get_path_param(apr_pool_t *pool, char *url,
 131                             const char *name, int scolon_sep)
 132 {
 133     char *path = NULL;
 134     char *pathdelims = "?&";
 135
 136     if (scolon_sep) {
 137         pathdelims = ";?&";
 138     }
 139     for (path = strstr(url, name); path; path = strstr(path + 1, name)) {
 140         path += strlen(name);
 141         if (*path == '=') {
 142             /*
 143              * Session path was found, get it's value
 144              */
 145             ++path;
 146             if (strlen(path)) {
 147                 char *q;
 148                 path = apr_strtok(apr_pstrdup(pool, path), pathdelims, &q);
 149                 return path;
 150             }
 151         }
 152     }
 153     return NULL;
 154 }
 155
 156 static char *get_cookie_param(request_rec *r, const char *name)
 157 {
 158     const char *cookies;
 159     const char *start_cookie;
 160
 161     if ((cookies = apr_table_get(r->headers_in, "Cookie"))) {
 162         for (start_cookie = ap_strstr_c(cookies, name); start_cookie;
 163              start_cookie = ap_strstr_c(start_cookie + 1, name)) {
 164             if (start_cookie == cookies ||
 165                 start_cookie[-1] == ';' ||
 166                 start_cookie[-1] == ',' ||
 167                 isspace(start_cookie[-1])) {
 168
 169                 start_cookie += strlen(name);
 170                 while(*start_cookie && isspace(*start_cookie))
 171                     ++start_cookie;
 172                 if (*start_cookie == '=' && start_cookie[1]) {
 173                     /*
 174                      * Session cookie was found, get it's value
 175                      */
 176                     char *end_cookie, *cookie;
 177                     ++start_cookie;
 178                     cookie = apr_pstrdup(r->pool, start_cookie);
 179                     if ((end_cookie = strchr(cookie, ';')) != NULL)
 180                         *end_cookie = '\0';
 181                     if((end_cookie = strchr(cookie, ',')) != NULL)
 182                         *end_cookie = '\0';
 183                     return cookie;
 184                 }
 185             }
 186         }
 187     }
 188     return NULL;
 189 }
 190
 191 /* Find the worker that has the 'route' defined
 192  */
 193 static proxy_worker *find_route_worker(proxy_balancer *balancer,
 194                                        const char *route, request_rec *r)
 195 {
 196     int i;
 197     int checking_standby;
 198     int checked_standby;
 199
 200     proxy_worker *worker;
 201
 202     checking_standby = checked_standby = 0;
 203     while (!checked_standby) {
 204         worker = (proxy_worker *)balancer->workers->elts;
 205         for (i = 0; i < balancer->workers->nelts; i++, worker++) {
 206             if ( (checking_standby ? !PROXY_WORKER_IS_STANDBY(worker) : PROXY_WORKER_IS_STANDBY(worker)) )
 207                 continue;
 208             if (*(worker->s->route) && strcmp(worker->s->route, route) == 0) {
 209                 if (worker && PROXY_WORKER_IS_USABLE(worker)) {
 210                     return worker;
 211                 } else {
 212                     /*
 213                      * If the worker is in error state run
 214                      * retry on that worker. It will be marked as
 215                      * operational if the retry timeout is elapsed.
 216                      * The worker might still be unusable, but we try
 217                      * anyway.
 218                      */
 219                     ap_proxy_retry_worker("BALANCER", worker, r->server);
 220                     if (PROXY_WORKER_IS_USABLE(worker)) {
 221                             return worker;
 222                     } else {
 223                         /*
 224                          * We have a worker that is unusable.
 225                          * It can be in error or disabled, but in case
 226                          * it has a redirection set use that redirection worker.
 227                          * This enables to safely remove the member from the
 228                          * balancer. Of course you will need some kind of
 229                          * session replication between those two remote.
 230                          */
 231                         if (*worker->s->redirect) {
 232                             proxy_worker *rworker = NULL;
 233                             rworker = find_route_worker(balancer, worker->s->redirect, r);
 234                             /* Check if the redirect worker is usable */
 235                             if (rworker && !PROXY_WORKER_IS_USABLE(rworker)) {
 236                                 /*
 237                                  * If the worker is in error state run
 238                                  * retry on that worker. It will be marked as
 239                                  * operational if the retry timeout is elapsed.
 240                                  * The worker might still be unusable, but we try
 241                                  * anyway.
 242                                  */
 243                                 ap_proxy_retry_worker("BALANCER", rworker, r->server);
 244                             }
 245                             if (rworker && PROXY_WORKER_IS_USABLE(rworker))
 246                                 return rworker;
 247                         }
 248                     }
 249                 }
 250             }
 251         }
 252         checked_standby = checking_standby++;
 253     }
 254     return NULL;
 255 }
 256
 257 static proxy_worker *find_session_route(proxy_balancer *balancer,
 258                                         request_rec *r,
 259                                         char **route,
 260                                         const char **sticky_used,
 261                                         char **url)
 262 {
 263     proxy_worker *worker = NULL;
 264
 265     if (!balancer->sticky)
 266         return NULL;
 267     /* Try to find the sticky route inside url */
 268     *route = get_path_param(r->pool, *url, balancer->sticky_path, balancer->scolonsep);
 269     if (*route) {
 270         ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 271                      "proxy: BALANCER: Found value %s for "
 272                      "stickysession %s", *route, balancer->sticky_path);
 273         *sticky_used =  balancer->sticky_path;
 274     }
 275     else {
 276         *route = get_cookie_param(r, balancer->sticky);
 277         if (*route) {
 278             *sticky_used =  balancer->sticky;
 279             ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 280                          "proxy: BALANCER: Found value %s for "
 281                          "stickysession %s", *route, balancer->sticky);
 282         }
 283     }
 284     /*
 285      * If we found a value for sticksession, find the first '.' within.
 286      * Everything after '.' (if present) is our route.
 287      */
 288     if ((*route) && ((*route = strchr(*route, '.')) != NULL ))
 289         (*route)++;
 290     if ((*route) && (**route)) {
 291         ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 292                                   "proxy: BALANCER: Found route %s", *route);
 293         /* We have a route in path or in cookie
 294          * Find the worker that has this route defined.
 295          */
 296         worker = find_route_worker(balancer, *route, r);
 297         if (worker && strcmp(*route, worker->s->route)) {
 298             /*
 299              * Notice that the route of the worker chosen is different from
 300              * the route supplied by the client.
 301              */
 302             apr_table_setn(r->subprocess_env, "BALANCER_ROUTE_CHANGED", "1");
 303             ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 304                          "proxy: BALANCER: Route changed from %s to %s",
 305                          *route, worker->s->route);
 306         }
 307         return worker;
 308     }
 309     else
 310         return NULL;
 311 }
 312
 313 static proxy_worker *find_best_worker(proxy_balancer *balancer,
 314                                       request_rec *r)
 315 {
 316     proxy_worker *candidate = NULL;
 317     apr_status_t rv;
 318
 319     if ((rv = PROXY_THREAD_LOCK(balancer)) != APR_SUCCESS) {
 320         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 321         "proxy: BALANCER: (%s). Lock failed for find_best_worker()", balancer->name);
 322         return NULL;
 323     }
 324
 325     candidate = (*balancer->lbmethod->finder)(balancer, r);
 326
 327     if (candidate)
 328         candidate->s->elected++;
 329
 330 /*
 331         PROXY_THREAD_UNLOCK(balancer);
 332         return NULL;
 333 */
 334
 335     if ((rv = PROXY_THREAD_UNLOCK(balancer)) != APR_SUCCESS) {
 336         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 337         "proxy: BALANCER: (%s). Unlock failed for find_best_worker()", balancer->name);
 338     }
 339
 340     if (candidate == NULL) {
 341         /* All the workers are in error state or disabled.
 342          * If the balancer has a timeout sleep for a while
 343          * and try again to find the worker. The chances are
 344          * that some other thread will release a connection.
 345          * By default the timeout is not set, and the server
 346          * returns SERVER_BUSY.
 347          */
 348 #if APR_HAS_THREADS
 349         if (balancer->timeout) {
 350             /* XXX: This can perhaps be build using some
 351              * smarter mechanism, like tread_cond.
 352              * But since the statuses can came from
 353              * different childs, use the provided algo.
 354              */
 355             apr_interval_time_t timeout = balancer->timeout;
 356             apr_interval_time_t step, tval = 0;
 357             /* Set the timeout to 0 so that we don't
 358              * end in infinite loop
 359              */
 360             balancer->timeout = 0;
 361             step = timeout / 100;
 362             while (tval < timeout) {
 363                 apr_sleep(step);
 364                 /* Try again */
 365                 if ((candidate = find_best_worker(balancer, r)))
 366                     break;
 367                 tval += step;
 368             }
 369             /* restore the timeout */
 370             balancer->timeout = timeout;
 371         }
 372 #endif
 373     }
 374
 375     return candidate;
 376
 377 }
 378
 379 static int rewrite_url(request_rec *r, proxy_worker *worker,
 380                         char **url)
 381 {
 382     const char *scheme = strstr(*url, "://");
 383     const char *path = NULL;
 384
 385     if (scheme)
 386         path = ap_strchr_c(scheme + 3, '/');
 387
 388     /* we break the URL into host, port, uri */
 389     if (!worker) {
 390         return ap_proxyerror(r, HTTP_BAD_REQUEST, apr_pstrcat(r->pool,
 391                              "missing worker. URI cannot be parsed: ", *url,
 392                              NULL));
 393     }
 394
 395     *url = apr_pstrcat(r->pool, worker->name, path, NULL);
 396
 397     return OK;
 398 }
 399
 400 static void force_recovery(proxy_balancer *balancer, server_rec *s)
 401 {
 402     int i;
 403     int ok = 0;
 404     proxy_worker **worker;
 405
 406     worker = (proxy_worker **)balancer->workers->elts;
 407     for (i = 0; i < balancer->workers->nelts; i++, worker++) {
 408         if (!((*worker)->s->status & PROXY_WORKER_IN_ERROR)) {
 409             ok = 1;
 410             break;
 411         }
 412         else {
 413             /* Try if we can recover */
 414             ap_proxy_retry_worker("BALANCER", *worker, s);
 415             if (!((*worker)->s->status & PROXY_WORKER_IN_ERROR)) {
 416                 ok = 1;
 417                 break;
 418             }
 419         }
 420     }
 421     if (!ok) {
 422         /* If all workers are in error state force the recovery.
 423          */
 424         worker = (proxy_worker **)balancer->workers->elts;
 425         for (i = 0; i < balancer->workers->nelts; i++, worker++) {
 426             ++(*worker)->s->retries;
 427             (*worker)->s->status &= ~PROXY_WORKER_IN_ERROR;
 428             ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
 429                          "proxy: BALANCER: (%s). Forcing recovery for worker (%s)",
 430                          balancer->name, (*worker)->hostname);
 431         }
 432     }
 433 }
 434
 435 static int proxy_balancer_pre_request(proxy_worker **worker,
 436                                       proxy_balancer **balancer,
 437                                       request_rec *r,
 438                                       proxy_server_conf *conf, char **url)
 439 {
 440     int access_status;
 441     proxy_worker *runtime;
 442     char *route = NULL;
 443     const char *sticky = NULL;
 444     apr_status_t rv;
 445
 446     *worker = NULL;
 447     /* Step 1: check if the url is for us
 448      * The url we can handle starts with 'balancer://'
 449      * If balancer is already provided skip the search
 450      * for balancer, because this is failover attempt.
 451      */
 452     if (!*balancer &&
 453         !(*balancer = ap_proxy_get_balancer(r->pool, conf, *url)))
 454         return DECLINED;
 455
 456     /* Step 2: Lock the LoadBalancer
 457      * XXX: perhaps we need the process lock here
 458      */
 459     if ((rv = PROXY_THREAD_LOCK(*balancer)) != APR_SUCCESS) {
 460         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 461                      "proxy: BALANCER: (%s). Lock failed for pre_request",
 462                      (*balancer)->name);
 463         return DECLINED;
 464     }
 465
 466     /* Step 3: force recovery */
 467     force_recovery(*balancer, r->server);
 468
 469     /* Step 4: find the session route */
 470     runtime = find_session_route(*balancer, r, &route, &sticky, url);
 471     if (runtime) {
 472         int i, total_factor = 0;
 473         proxy_worker *workers;
 474         /* We have a sticky load balancer
 475          * Update the workers status
 476          * so that even session routes get
 477          * into account.
 478          */
 479         workers = (proxy_worker *)(*balancer)->workers->elts;
 480         for (i = 0; i < (*balancer)->workers->nelts; i++) {
 481             /* Take into calculation only the workers that are
 482              * not in error state or not disabled.
 483              *
 484              * TODO: Abstract the below, since this is dependent
 485              *       on the LB implementation
 486              */
 487             if (PROXY_WORKER_IS_USABLE(workers)) {
 488                 workers->s->lbstatus += workers->s->lbfactor;
 489                 total_factor += workers->s->lbfactor;
 490             }
 491             workers++;
 492         }
 493         runtime->s->lbstatus -= total_factor;
 494         runtime->s->elected++;
 495
 496         *worker = runtime;
 497     }
 498     else if (route && (*balancer)->sticky_force) {
 499         int i, member_of = 0;
 500         proxy_worker *workers;
 501         /*
 502          * We have a route provided that doesn't match the
 503          * balancer name. See if the provider route is the
 504          * member of the same balancer in which case return 503
 505          */
 506         workers = (proxy_worker *)(*balancer)->workers->elts;
 507         for (i = 0; i < (*balancer)->workers->nelts; i++) {
 508             if (*(workers->s->route) && strcmp(workers->s->route, route) == 0) {
 509                 member_of = 1;
 510                 break;
 511             }
 512             workers++;
 513         }
 514         if (member_of) {
 515             ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
 516                          "proxy: BALANCER: (%s). All workers are in error state for route (%s)",
 517                          (*balancer)->name, route);
 518             if ((rv = PROXY_THREAD_UNLOCK(*balancer)) != APR_SUCCESS) {
 519                 ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 520                              "proxy: BALANCER: (%s). Unlock failed for pre_request",
 521                              (*balancer)->name);
 522             }
 523             return HTTP_SERVICE_UNAVAILABLE;
 524         }
 525     }
 526
 527     if ((rv = PROXY_THREAD_UNLOCK(*balancer)) != APR_SUCCESS) {
 528         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 529                      "proxy: BALANCER: (%s). Unlock failed for pre_request",
 530                      (*balancer)->name);
 531     }
 532     if (!*worker) {
 533         runtime = find_best_worker(*balancer, r);
 534         if (!runtime) {
 535             ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
 536                          "proxy: BALANCER: (%s). All workers are in error state",
 537                          (*balancer)->name);
 538
 539             return HTTP_SERVICE_UNAVAILABLE;
 540         }
 541         if ((*balancer)->sticky && runtime) {
 542             /*
 543              * This balancer has sticky sessions and the client either has not
 544              * supplied any routing information or all workers for this route
 545              * including possible redirect and hotstandby workers are in error
 546              * state, but we have found another working worker for this
 547              * balancer where we can send the request. Thus notice that we have
 548              * changed the route to the backend.
 549              */
 550             apr_table_setn(r->subprocess_env, "BALANCER_ROUTE_CHANGED", "1");
 551         }
 552         *worker = runtime;
 553     }
 554
 555     (*worker)->s->busy++;
 556
 557     /* Add balancer/worker info to env. */
 558     apr_table_setn(r->subprocess_env,
 559                    "BALANCER_NAME", (*balancer)->name);
 560     apr_table_setn(r->subprocess_env,
 561                    "BALANCER_WORKER_NAME", (*worker)->name);
 562     apr_table_setn(r->subprocess_env,
 563                    "BALANCER_WORKER_ROUTE", (*worker)->s->route);
 564
 565     /* Rewrite the url from 'balancer://url'
 566      * to the 'worker_scheme://worker_hostname[:worker_port]/url'
 567      * This replaces the balancers fictional name with the
 568      * real hostname of the elected worker.
 569      */
 570     access_status = rewrite_url(r, *worker, url);
 571     /* Add the session route to request notes if present */
 572     if (route) {
 573         apr_table_setn(r->notes, "session-sticky", sticky);
 574         apr_table_setn(r->notes, "session-route", route);
 575
 576         /* Add session info to env. */
 577         apr_table_setn(r->subprocess_env,
 578                        "BALANCER_SESSION_STICKY", sticky);
 579         apr_table_setn(r->subprocess_env,
 580                        "BALANCER_SESSION_ROUTE", route);
 581     }
 582     ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 583                  "proxy: BALANCER (%s) worker (%s) rewritten to %s",
 584                  (*balancer)->name, (*worker)->name, *url);
 585
 586     return access_status;
 587 }
 588
 589 static int proxy_balancer_post_request(proxy_worker *worker,
 590                                        proxy_balancer *balancer,
 591                                        request_rec *r,
 592                                        proxy_server_conf *conf)
 593 {
 594
 595 #if 0
 596     apr_status_t rv;
 597
 598     if ((rv = PROXY_THREAD_LOCK(balancer)) != APR_SUCCESS) {
 599         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 600             "proxy: BALANCER: (%s). Lock failed for post_request",
 601             balancer->name);
 602         return HTTP_INTERNAL_SERVER_ERROR;
 603     }
 604     /* TODO: placeholder for post_request actions
 605      */
 606
 607     if ((rv = PROXY_THREAD_UNLOCK(balancer)) != APR_SUCCESS) {
 608         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 609             "proxy: BALANCER: (%s). Unlock failed for post_request",
 610             balancer->name);
 611     }
 612     ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 613                  "proxy_balancer_post_request for (%s)", balancer->name);
 614
 615 #endif
 616
 617     if (worker && worker->s->busy)
 618         worker->s->busy--;
 619
 620     return OK;
 621
 622 }
 623
 624 static void recalc_factors(proxy_balancer *balancer)
 625 {
 626     int i;
 627     proxy_worker *workers;
 628
 629
 630     /* Recalculate lbfactors */
 631     workers = (proxy_worker *)balancer->workers->elts;
 632     /* Special case if there is only one worker it's
 633      * load factor will always be 1
 634      */
 635     if (balancer->workers->nelts == 1) {
 636         workers->s->lbstatus = workers->s->lbfactor = 1;
 637         return;
 638     }
 639     for (i = 0; i < balancer->workers->nelts; i++) {
 640         /* Update the status entries */
 641         workers[i].s->lbstatus = workers[i].s->lbfactor;
 642     }
 643 }
 644
 645 /* post_config hook: */
 646 static int balancer_init(apr_pool_t *p, apr_pool_t *plog,
 647                          apr_pool_t *ptemp, server_rec *s)
 648 {
 649     void *data;
 650     const char *userdata_key = "mod_proxy_balancer_init";
 651     apr_uuid_t uuid;
 652
 653     /* balancer_init() will be called twice during startup.  So, only
 654      * set up the static data the second time through. */
 655     apr_pool_userdata_get(&data, userdata_key, s->process->pool);
 656     if (!data) {
 657         apr_pool_userdata_set((const void *)1, userdata_key,
 658                                apr_pool_cleanup_null, s->process->pool);
 659         return OK;
 660     }
 661
 662     /* Retrieve a UUID and store the nonce for the lifetime of
 663      * the process. */
 664     apr_uuid_get(&uuid);
 665     apr_uuid_format(balancer_nonce, &uuid);
 666
 667     return OK;
 668 }
 669
 670 /* Manages the loadfactors and member status
 671  */
 672 static int balancer_handler(request_rec *r)
 673 {
 674     void *sconf = r->server->module_config;
 675     proxy_server_conf *conf = (proxy_server_conf *)
 676         ap_get_module_config(sconf, &proxy_module);
 677     proxy_balancer *balancer, *bsel = NULL;
 678     proxy_worker *worker, *wsel = NULL;
 679     apr_table_t *params = apr_table_make(r->pool, 10);
 680     int access_status;
 681     int i, n;
 682     const char *name;
 683
 684     /* is this for us? */
 685     if (strcmp(r->handler, "balancer-manager"))
 686         return DECLINED;
 687     r->allowed = (AP_METHOD_BIT << M_GET);
 688     if (r->method_number != M_GET)
 689         return DECLINED;
 690
 691     if (r->args) {
 692         char *args = apr_pstrdup(r->pool, r->args);
 693         char *tok, *val;
 694         while (args && *args) {
 695             if ((val = ap_strchr(args, '='))) {
 696                 *val++ = '\0';
 697                 if ((tok = ap_strchr(val, '&')))
 698                     *tok++ = '\0';
 699                 /*
 700                  * Special case: workers are allowed path information
 701                  */
 702                 if ((access_status = ap_unescape_url(val)) != OK)
 703                     if (strcmp(args, "w") || (access_status !=  HTTP_NOT_FOUND))
 704                         return access_status;
 705                 apr_table_setn(params, args, val);
 706                 args = tok;
 707             }
 708             else
 709                 return HTTP_BAD_REQUEST;
 710         }
 711     }
 712
 713     /* Check that the supplied nonce matches this server's nonce;
 714      * otherwise ignore all parameters, to prevent a CSRF attack. */
 715     if ((name = apr_table_get(params, "nonce")) == NULL
 716         || strcmp(balancer_nonce, name) != 0) {
 717         apr_table_clear(params);
 718     }
 719
 720     if ((name = apr_table_get(params, "b")))
 721         bsel = ap_proxy_get_balancer(r->pool, conf,
 722             apr_pstrcat(r->pool, "balancer://", name, NULL));
 723     if ((name = apr_table_get(params, "w"))) {
 724         proxy_worker *ws;
 725
 726         ws = ap_proxy_get_worker(r->pool, conf, name);
 727         if (bsel && ws) {
 728             worker = (proxy_worker *)bsel->workers->elts;
 729             for (n = 0; n < bsel->workers->nelts; n++) {
 730                 if (strcasecmp(worker->name, ws->name) == 0) {
 731                     wsel = worker;
 732                     break;
 733                 }
 734                 ++worker;
 735             }
 736         }
 737     }
 738     /* First set the params */
 739     /*
 740      * Note that it is not possible set the proxy_balancer because it is not
 741      * in shared memory.
 742      */
 743     if (wsel) {
 744         const char *val;
 745         if ((val = apr_table_get(params, "lf"))) {
 746             int ival = atoi(val);
 747             if (ival >= 1 && ival <= 100) {
 748                 wsel->s->lbfactor = ival;
 749                 if (bsel)
 750                     recalc_factors(bsel);
 751             }
 752         }
 753         if ((val = apr_table_get(params, "wr"))) {
 754             if (strlen(val) && strlen(val) < PROXY_WORKER_MAX_ROUTE_SIZ)
 755                 strcpy(wsel->s->route, val);
 756             else
 757                 *wsel->s->route = '\0';
 758         }
 759         if ((val = apr_table_get(params, "rr"))) {
 760             if (strlen(val) && strlen(val) < PROXY_WORKER_MAX_ROUTE_SIZ)
 761                 strcpy(wsel->s->redirect, val);
 762             else
 763                 *wsel->s->redirect = '\0';
 764         }
 765         if ((val = apr_table_get(params, "dw"))) {
 766             if (!strcasecmp(val, "Disable"))
 767                 wsel->s->status |= PROXY_WORKER_DISABLED;
 768             else if (!strcasecmp(val, "Enable"))
 769                 wsel->s->status &= ~PROXY_WORKER_DISABLED;
 770         }
 771         if ((val = apr_table_get(params, "ls"))) {
 772             int ival = atoi(val);
 773             if (ival >= 0 && ival <= 99) {
 774                 wsel->s->lbset = ival;
 775              }
 776         }
 777
 778     }
 779     if (apr_table_get(params, "xml")) {
 780         ap_set_content_type(r, "text/xml");
 781         ap_rputs("<?xml version=\"1.0\" encoding=\"UTF-8\" ?>\n", r);
 782         ap_rputs("<httpd:manager xmlns:httpd=\"http://httpd.apache.org\">\n", r);
 783         ap_rputs("  <httpd:balancers>\n", r);
 784         balancer = (proxy_balancer *)conf->balancers->elts;
 785         for (i = 0; i < conf->balancers->nelts; i++) {
 786             ap_rputs("    <httpd:balancer>\n", r);
 787             ap_rvputs(r, "      <httpd:name>", balancer->name, "</httpd:name>\n", NULL);
 788             ap_rputs("      <httpd:workers>\n", r);
 789             worker = (proxy_worker *)balancer->workers->elts;
 790             for (n = 0; n < balancer->workers->nelts; n++) {
 791                 ap_rputs("        <httpd:worker>\n", r);
 792                 ap_rvputs(r, "          <httpd:scheme>", worker->scheme,
 793                           "</httpd:scheme>\n", NULL);
 794                 ap_rvputs(r, "          <httpd:hostname>", worker->hostname,
 795                           "</httpd:hostname>\n", NULL);
 796                ap_rprintf(r, "          <httpd:loadfactor>%d</httpd:loadfactor>\n",
 797                           worker->s->lbfactor);
 798                 ap_rputs("        </httpd:worker>\n", r);
 799                 ++worker;
 800             }
 801             ap_rputs("      </httpd:workers>\n", r);
 802             ap_rputs("    </httpd:balancer>\n", r);
 803             ++balancer;
 804         }
 805         ap_rputs("  </httpd:balancers>\n", r);
 806         ap_rputs("</httpd:manager>", r);
 807     }
 808     else {
 809         ap_set_content_type(r, "text/html; charset=ISO-8859-1");
 810         ap_rputs(DOCTYPE_HTML_3_2
 811                  "<html><head><title>Balancer Manager</title></head>\n", r);
 812         ap_rputs("<body><h1>Load Balancer Manager for ", r);
 813         ap_rvputs(r, ap_get_server_name(r), "</h1>\n\n", NULL);
 814         ap_rvputs(r, "<dl><dt>Server Version: ",
 815                   ap_get_server_description(), "</dt>\n", NULL);
 816         ap_rvputs(r, "<dt>Server Built: ",
 817                   ap_get_server_built(), "\n</dt></dl>\n", NULL);
 818         balancer = (proxy_balancer *)conf->balancers->elts;
 819         for (i = 0; i < conf->balancers->nelts; i++) {
 820
 821             ap_rputs("<hr />\n<h3>LoadBalancer Status for ", r);
 822             ap_rvputs(r, balancer->name, "</h3>\n\n", NULL);
 823             ap_rputs("\n\n<table border=\"0\" style=\"text-align: left;\"><tr>"
 824                 "<th>StickySession</th><th>Timeout</th><th>FailoverAttempts</th><th>Method</th>"
 825                 "</tr>\n<tr>", r);
 826             if (balancer->sticky) {
 827                 if (strcmp(balancer->sticky, balancer->sticky_path)) {
 828                     ap_rvputs(r, "<td>", balancer->sticky, " | ",
 829                               balancer->sticky_path, NULL);
 830                 }
 831                 else {
 832                     ap_rvputs(r, "<td>", balancer->sticky, NULL);
 833                 }
 834             }
 835             else {
 836                 ap_rputs("<td> - ", r);
 837             }
 838             ap_rprintf(r, "</td><td>%" APR_TIME_T_FMT "</td>",
 839                 apr_time_sec(balancer->timeout));
 840             ap_rprintf(r, "<td>%d</td>\n", balancer->max_attempts);
 841             ap_rprintf(r, "<td>%s</td>\n",
 842                        balancer->lbmethod->name);
 843             ap_rputs("</table>\n<br />", r);
 844             ap_rputs("\n\n<table border=\"0\" style=\"text-align: left;\"><tr>"
 845                 "<th>Worker URL</th>"
 846                 "<th>Route</th><th>RouteRedir</th>"
 847                 "<th>Factor</th><th>Set</th><th>Status</th>"
 848                 "<th>Elected</th><th>To</th><th>From</th>"
 849                 "</tr>\n", r);
 850
 851             worker = (proxy_worker *)balancer->workers->elts;
 852             for (n = 0; n < balancer->workers->nelts; n++) {
 853                 char fbuf[50];
 854                 ap_rvputs(r, "<tr>\n<td><a href=\"", r->uri, "?b=",
 855                           balancer->name + sizeof("balancer://") - 1, "&w=",
 856                           ap_escape_uri(r->pool, worker->name),
 857                           "&nonce=", balancer_nonce,
 858                           "\">", NULL);
 859                 ap_rvputs(r, worker->name, "</a></td>", NULL);
 860                 ap_rvputs(r, "<td>", ap_escape_html(r->pool, worker->s->route),
 861                           NULL);
 862                 ap_rvputs(r, "</td><td>",
 863                           ap_escape_html(r->pool, worker->s->redirect), NULL);
 864                 ap_rprintf(r, "</td><td>%d</td>", worker->s->lbfactor);
 865                 ap_rprintf(r, "<td>%d</td><td>", worker->s->lbset);
 866                 if (worker->s->status & PROXY_WORKER_DISABLED)
 867                    ap_rputs("Dis ", r);
 868                 if (worker->s->status & PROXY_WORKER_IN_ERROR)
 869                    ap_rputs("Err ", r);
 870                 if (worker->s->status & PROXY_WORKER_STOPPED)
 871                    ap_rputs("Stop ", r);
 872                 if (worker->s->status & PROXY_WORKER_HOT_STANDBY)
 873                    ap_rputs("Stby ", r);
 874                 if (PROXY_WORKER_IS_USABLE(worker))
 875                     ap_rputs("Ok", r);
 876                 if (!PROXY_WORKER_IS_INITIALIZED(worker))
 877                     ap_rputs("-", r);
 878                 ap_rputs("</td>", r);
 879                 ap_rprintf(r, "<td>%" APR_SIZE_T_FMT "</td><td>", worker->s->elected);
 880                 ap_rputs(apr_strfsize(worker->s->transferred, fbuf), r);
 881                 ap_rputs("</td><td>", r);
 882                 ap_rputs(apr_strfsize(worker->s->read, fbuf), r);
 883                 ap_rputs("</td></tr>\n", r);
 884
 885                 ++worker;
 886             }
 887             ap_rputs("</table>\n", r);
 888             ++balancer;
 889         }
 890         ap_rputs("<hr />\n", r);
 891         if (wsel && bsel) {
 892             ap_rputs("<h3>Edit worker settings for ", r);
 893             ap_rvputs(r, wsel->name, "</h3>\n", NULL);
 894             ap_rvputs(r, "<form method=\"GET\" action=\"", NULL);
 895             ap_rvputs(r, r->uri, "\">\n<dl>", NULL);
 896             ap_rputs("<table><tr><td>Load factor:</td><td><input name=\"lf\" type=text ", r);
 897             ap_rprintf(r, "value=\"%d\"></td></tr>\n", wsel->s->lbfactor);
 898             ap_rputs("<tr><td>LB Set:</td><td><input name=\"ls\" type=text ", r);
 899             ap_rprintf(r, "value=\"%d\"></td></tr>\n", wsel->s->lbset);
 900             ap_rputs("<tr><td>Route:</td><td><input name=\"wr\" type=text ", r);
 901             ap_rvputs(r, "value=\"", ap_escape_html(r->pool, wsel->s->route),
 902                       NULL);
 903             ap_rputs("\"></td></tr>\n", r);
 904             ap_rputs("<tr><td>Route Redirect:</td><td><input name=\"rr\" type=text ", r);
 905             ap_rvputs(r, "value=\"", ap_escape_html(r->pool, wsel->s->redirect),
 906                       NULL);
 907             ap_rputs("\"></td></tr>\n", r);
 908             ap_rputs("<tr><td>Status:</td><td>Disabled: <input name=\"dw\" value=\"Disable\" type=radio", r);
 909             if (wsel->s->status & PROXY_WORKER_DISABLED)
 910                 ap_rputs(" checked", r);
 911             ap_rputs("> | Enabled: <input name=\"dw\" value=\"Enable\" type=radio", r);
 912             if (!(wsel->s->status & PROXY_WORKER_DISABLED))
 913                 ap_rputs(" checked", r);
 914             ap_rputs("></td></tr>\n", r);
 915             ap_rputs("<tr><td colspan=2><input type=submit value=\"Submit\"></td></tr>\n", r);
 916             ap_rvputs(r, "</table>\n<input type=hidden name=\"w\" ",  NULL);
 917             ap_rvputs(r, "value=\"", ap_escape_uri(r->pool, wsel->name), "\">\n", NULL);
 918             ap_rvputs(r, "<input type=hidden name=\"b\" ", NULL);
 919             ap_rvputs(r, "value=\"", bsel->name + sizeof("balancer://") - 1,
 920                       "\">\n", NULL);
 921             ap_rvputs(r, "<input type=hidden name=\"nonce\" value=\"",
 922                       balancer_nonce, "\">\n", NULL);
 923             ap_rvputs(r, "</form>\n", NULL);
 924             ap_rputs("<hr />\n", r);
 925         }
 926         ap_rputs(ap_psignature("",r), r);
 927         ap_rputs("</body></html>\n", r);
 928     }
 929     return OK;
 930 }
 931
 932 static void child_init(apr_pool_t *p, server_rec *s)
 933 {
 934     while (s) {
 935         void *sconf = s->module_config;
 936         proxy_server_conf *conf;
 937         proxy_balancer *balancer;
 938         int i;
 939         conf = (proxy_server_conf *)ap_get_module_config(sconf, &proxy_module);
 940
 941         /* Initialize shared scoreboard data */
 942         balancer = (proxy_balancer *)conf->balancers->elts;
 943         for (i = 0; i < conf->balancers->nelts; i++) {
 944             proxy_balancer_method *lbmethod = balancer->lbmethod;
 945             if (balancer->lbmethod!=NULL && balancer->lbmethod->reset != NULL)
 946                balancer->lbmethod->reset(balancer, s);
 947             init_balancer_members(conf, s, balancer);
 948             balancer++;
 949         }
 950         s = s->next;
 951     }
 952
 953 }
 954
 955 static void ap_proxy_balancer_register_hook(apr_pool_t *p)
 956 {
 957     /* Only the mpm_winnt has child init hook handler.
 958      * make sure that we are called after the mpm
 959      * initializes
 960      */
 961     static const char *const aszPred[] = { "mpm_winnt.c", NULL};
 962      /* manager handler */
 963     ap_hook_post_config(balancer_init, NULL, NULL, APR_HOOK_MIDDLE);
 964     ap_hook_handler(balancer_handler, NULL, NULL, APR_HOOK_FIRST);
 965     ap_hook_child_init(child_init, aszPred, NULL, APR_HOOK_MIDDLE);
 966     proxy_hook_pre_request(proxy_balancer_pre_request, NULL, NULL, APR_HOOK_FIRST);
 967     proxy_hook_post_request(proxy_balancer_post_request, NULL, NULL, APR_HOOK_FIRST);
 968     proxy_hook_canon_handler(proxy_balancer_canon, NULL, NULL, APR_HOOK_FIRST);
 969 }
 970
 971 module AP_MODULE_DECLARE_DATA proxy_balancer_module = {
 972     STANDARD20_MODULE_STUFF,
 973     NULL,       /* create per-directory config structure */
 974     NULL,       /* merge per-directory config structures */
 975     NULL,       /* create per-server config structure */
 976     NULL,       /* merge per-server config structures */
 977     NULL,       /* command apr_table_t */
 978     ap_proxy_balancer_register_hook /* register hooks */
 979 };