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 **workers;
 201     proxy_worker *worker;
 202
 203     checking_standby = checked_standby = 0;
 204     while (!checked_standby) {
 205         workers = (proxy_worker **)balancer->workers->elts;
 206         for (i = 0; i < balancer->workers->nelts; i++, workers++) {
 207             worker = *workers;
 208             if ( (checking_standby ? !PROXY_WORKER_IS_STANDBY(worker) : PROXY_WORKER_IS_STANDBY(worker)) )
 209                 continue;
 210             if (*(worker->s->route) && strcmp(worker->s->route, route) == 0) {
 211                 if (worker && PROXY_WORKER_IS_USABLE(worker)) {
 212                     return worker;
 213                 } else {
 214                     /*
 215                      * If the worker is in error state run
 216                      * retry on that worker. It will be marked as
 217                      * operational if the retry timeout is elapsed.
 218                      * The worker might still be unusable, but we try
 219                      * anyway.
 220                      */
 221                     ap_proxy_retry_worker("BALANCER", worker, r->server);
 222                     if (PROXY_WORKER_IS_USABLE(worker)) {
 223                             return worker;
 224                     } else {
 225                         /*
 226                          * We have a worker that is unusable.
 227                          * It can be in error or disabled, but in case
 228                          * it has a redirection set use that redirection worker.
 229                          * This enables to safely remove the member from the
 230                          * balancer. Of course you will need some kind of
 231                          * session replication between those two remote.
 232                          */
 233                         if (*worker->s->redirect) {
 234                             proxy_worker *rworker = NULL;
 235                             rworker = find_route_worker(balancer, worker->s->redirect, r);
 236                             /* Check if the redirect worker is usable */
 237                             if (rworker && !PROXY_WORKER_IS_USABLE(rworker)) {
 238                                 /*
 239                                  * If the worker is in error state run
 240                                  * retry on that worker. It will be marked as
 241                                  * operational if the retry timeout is elapsed.
 242                                  * The worker might still be unusable, but we try
 243                                  * anyway.
 244                                  */
 245                                 ap_proxy_retry_worker("BALANCER", rworker, r->server);
 246                             }
 247                             if (rworker && PROXY_WORKER_IS_USABLE(rworker))
 248                                 return rworker;
 249                         }
 250                     }
 251                 }
 252             }
 253         }
 254         checked_standby = checking_standby++;
 255     }
 256     return NULL;
 257 }
 258
 259 static proxy_worker *find_session_route(proxy_balancer *balancer,
 260                                         request_rec *r,
 261                                         char **route,
 262                                         const char **sticky_used,
 263                                         char **url)
 264 {
 265     proxy_worker *worker = NULL;
 266
 267     if (!balancer->sticky)
 268         return NULL;
 269     /* Try to find the sticky route inside url */
 270     *route = get_path_param(r->pool, *url, balancer->sticky_path, balancer->scolonsep);
 271     if (*route) {
 272         ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 273                      "proxy: BALANCER: Found value %s for "
 274                      "stickysession %s", *route, balancer->sticky_path);
 275         *sticky_used =  balancer->sticky_path;
 276     }
 277     else {
 278         *route = get_cookie_param(r, balancer->sticky);
 279         if (*route) {
 280             *sticky_used =  balancer->sticky;
 281             ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 282                          "proxy: BALANCER: Found value %s for "
 283                          "stickysession %s", *route, balancer->sticky);
 284         }
 285     }
 286     /*
 287      * If we found a value for sticksession, find the first '.' within.
 288      * Everything after '.' (if present) is our route.
 289      */
 290     if ((*route) && ((*route = strchr(*route, '.')) != NULL ))
 291         (*route)++;
 292     if ((*route) && (**route)) {
 293         ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 294                                   "proxy: BALANCER: Found route %s", *route);
 295         /* We have a route in path or in cookie
 296          * Find the worker that has this route defined.
 297          */
 298         worker = find_route_worker(balancer, *route, r);
 299         if (worker && strcmp(*route, worker->s->route)) {
 300             /*
 301              * Notice that the route of the worker chosen is different from
 302              * the route supplied by the client.
 303              */
 304             apr_table_setn(r->subprocess_env, "BALANCER_ROUTE_CHANGED", "1");
 305             ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 306                          "proxy: BALANCER: Route changed from %s to %s",
 307                          *route, worker->s->route);
 308         }
 309         return worker;
 310     }
 311     else
 312         return NULL;
 313 }
 314
 315 static proxy_worker *find_best_worker(proxy_balancer *balancer,
 316                                       request_rec *r)
 317 {
 318     proxy_worker *candidate = NULL;
 319     apr_status_t rv;
 320
 321     if ((rv = PROXY_THREAD_LOCK(balancer)) != APR_SUCCESS) {
 322         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 323         "proxy: BALANCER: (%s). Lock failed for find_best_worker()", balancer->name);
 324         return NULL;
 325     }
 326
 327     candidate = (*balancer->lbmethod->finder)(balancer, r);
 328
 329     if (candidate)
 330         candidate->s->elected++;
 331
 332 /*
 333         PROXY_THREAD_UNLOCK(balancer);
 334         return NULL;
 335 */
 336
 337     if ((rv = PROXY_THREAD_UNLOCK(balancer)) != APR_SUCCESS) {
 338         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 339         "proxy: BALANCER: (%s). Unlock failed for find_best_worker()", balancer->name);
 340     }
 341
 342     if (candidate == NULL) {
 343         /* All the workers are in error state or disabled.
 344          * If the balancer has a timeout sleep for a while
 345          * and try again to find the worker. The chances are
 346          * that some other thread will release a connection.
 347          * By default the timeout is not set, and the server
 348          * returns SERVER_BUSY.
 349          */
 350 #if APR_HAS_THREADS
 351         if (balancer->timeout) {
 352             /* XXX: This can perhaps be build using some
 353              * smarter mechanism, like tread_cond.
 354              * But since the statuses can came from
 355              * different childs, use the provided algo.
 356              */
 357             apr_interval_time_t timeout = balancer->timeout;
 358             apr_interval_time_t step, tval = 0;
 359             /* Set the timeout to 0 so that we don't
 360              * end in infinite loop
 361              */
 362             balancer->timeout = 0;
 363             step = timeout / 100;
 364             while (tval < timeout) {
 365                 apr_sleep(step);
 366                 /* Try again */
 367                 if ((candidate = find_best_worker(balancer, r)))
 368                     break;
 369                 tval += step;
 370             }
 371             /* restore the timeout */
 372             balancer->timeout = timeout;
 373         }
 374 #endif
 375     }
 376
 377     return candidate;
 378
 379 }
 380
 381 static int rewrite_url(request_rec *r, proxy_worker *worker,
 382                         char **url)
 383 {
 384     const char *scheme = strstr(*url, "://");
 385     const char *path = NULL;
 386
 387     if (scheme)
 388         path = ap_strchr_c(scheme + 3, '/');
 389
 390     /* we break the URL into host, port, uri */
 391     if (!worker) {
 392         return ap_proxyerror(r, HTTP_BAD_REQUEST, apr_pstrcat(r->pool,
 393                              "missing worker. URI cannot be parsed: ", *url,
 394                              NULL));
 395     }
 396
 397     *url = apr_pstrcat(r->pool, worker->name, path, NULL);
 398
 399     return OK;
 400 }
 401
 402 static void force_recovery(proxy_balancer *balancer, server_rec *s)
 403 {
 404     int i;
 405     int ok = 0;
 406     proxy_worker **worker;
 407
 408     worker = (proxy_worker **)balancer->workers->elts;
 409     for (i = 0; i < balancer->workers->nelts; i++, worker++) {
 410         if (!((*worker)->s->status & PROXY_WORKER_IN_ERROR)) {
 411             ok = 1;
 412             break;
 413         }
 414         else {
 415             /* Try if we can recover */
 416             ap_proxy_retry_worker("BALANCER", *worker, s);
 417             if (!((*worker)->s->status & PROXY_WORKER_IN_ERROR)) {
 418                 ok = 1;
 419                 break;
 420             }
 421         }
 422     }
 423     if (!ok) {
 424         /* If all workers are in error state force the recovery.
 425          */
 426         worker = (proxy_worker **)balancer->workers->elts;
 427         for (i = 0; i < balancer->workers->nelts; i++, worker++) {
 428             ++(*worker)->s->retries;
 429             (*worker)->s->status &= ~PROXY_WORKER_IN_ERROR;
 430             ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
 431                          "proxy: BALANCER: (%s). Forcing recovery for worker (%s)",
 432                          balancer->name, (*worker)->hostname);
 433         }
 434     }
 435 }
 436
 437 static int proxy_balancer_pre_request(proxy_worker **worker,
 438                                       proxy_balancer **balancer,
 439                                       request_rec *r,
 440                                       proxy_server_conf *conf, char **url)
 441 {
 442     int access_status;
 443     proxy_worker *runtime;
 444     char *route = NULL;
 445     const char *sticky = NULL;
 446     apr_status_t rv;
 447
 448     *worker = NULL;
 449     /* Step 1: check if the url is for us
 450      * The url we can handle starts with 'balancer://'
 451      * If balancer is already provided skip the search
 452      * for balancer, because this is failover attempt.
 453      */
 454     if (!*balancer &&
 455         !(*balancer = ap_proxy_get_balancer(r->pool, conf, *url)))
 456         return DECLINED;
 457
 458     /* Step 2: Lock the LoadBalancer
 459      * XXX: perhaps we need the process lock here
 460      */
 461     if ((rv = PROXY_THREAD_LOCK(*balancer)) != APR_SUCCESS) {
 462         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 463                      "proxy: BALANCER: (%s). Lock failed for pre_request",
 464                      (*balancer)->name);
 465         return DECLINED;
 466     }
 467
 468     /* Step 3: force recovery */
 469     force_recovery(*balancer, r->server);
 470
 471     /* Step 4: find the session route */
 472     runtime = find_session_route(*balancer, r, &route, &sticky, url);
 473     if (runtime) {
 474         int i, total_factor = 0;
 475         proxy_worker **workers;
 476         /* We have a sticky load balancer
 477          * Update the workers status
 478          * so that even session routes get
 479          * into account.
 480          */
 481         workers = (proxy_worker **)(*balancer)->workers->elts;
 482         for (i = 0; i < (*balancer)->workers->nelts; i++) {
 483             /* Take into calculation only the workers that are
 484              * not in error state or not disabled.
 485              *
 486              * TODO: Abstract the below, since this is dependent
 487              *       on the LB implementation
 488              */
 489             if (PROXY_WORKER_IS_USABLE(*workers)) {
 490                 (*workers)->s->lbstatus += (*workers)->s->lbfactor;
 491                 total_factor += (*workers)->s->lbfactor;
 492             }
 493             workers++;
 494         }
 495         runtime->s->lbstatus -= total_factor;
 496         runtime->s->elected++;
 497
 498         *worker = runtime;
 499     }
 500     else if (route && (*balancer)->sticky_force) {
 501         int i, member_of = 0;
 502         proxy_worker **workers;
 503         /*
 504          * We have a route provided that doesn't match the
 505          * balancer name. See if the provider route is the
 506          * member of the same balancer in which case return 503
 507          */
 508         workers = (proxy_worker **)(*balancer)->workers->elts;
 509         for (i = 0; i < (*balancer)->workers->nelts; i++) {
 510             if (*((*workers)->s->route) && strcmp((*workers)->s->route, route) == 0) {
 511                 member_of = 1;
 512                 break;
 513             }
 514             workers++;
 515         }
 516         if (member_of) {
 517             ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
 518                          "proxy: BALANCER: (%s). All workers are in error state for route (%s)",
 519                          (*balancer)->name, route);
 520             if ((rv = PROXY_THREAD_UNLOCK(*balancer)) != APR_SUCCESS) {
 521                 ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 522                              "proxy: BALANCER: (%s). Unlock failed for pre_request",
 523                              (*balancer)->name);
 524             }
 525             return HTTP_SERVICE_UNAVAILABLE;
 526         }
 527     }
 528
 529     if ((rv = PROXY_THREAD_UNLOCK(*balancer)) != APR_SUCCESS) {
 530         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 531                      "proxy: BALANCER: (%s). Unlock failed for pre_request",
 532                      (*balancer)->name);
 533     }
 534     if (!*worker) {
 535         runtime = find_best_worker(*balancer, r);
 536         if (!runtime) {
 537             if ((*balancer)->workers->nelts) {
 538                 ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
 539                             "proxy: BALANCER: (%s). All workers are in error state",
 540                             (*balancer)->name);
 541             } else {
 542                 ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
 543                             "proxy: BALANCER: (%s). No workers in balancer",
 544                             (*balancer)->name);
 545             }
 546
 547             return HTTP_SERVICE_UNAVAILABLE;
 548         }
 549         if ((*balancer)->sticky && runtime) {
 550             /*
 551              * This balancer has sticky sessions and the client either has not
 552              * supplied any routing information or all workers for this route
 553              * including possible redirect and hotstandby workers are in error
 554              * state, but we have found another working worker for this
 555              * balancer where we can send the request. Thus notice that we have
 556              * changed the route to the backend.
 557              */
 558             apr_table_setn(r->subprocess_env, "BALANCER_ROUTE_CHANGED", "1");
 559         }
 560         *worker = runtime;
 561     }
 562
 563     (*worker)->s->busy++;
 564
 565     /* Add balancer/worker info to env. */
 566     apr_table_setn(r->subprocess_env,
 567                    "BALANCER_NAME", (*balancer)->name);
 568     apr_table_setn(r->subprocess_env,
 569                    "BALANCER_WORKER_NAME", (*worker)->name);
 570     apr_table_setn(r->subprocess_env,
 571                    "BALANCER_WORKER_ROUTE", (*worker)->s->route);
 572
 573     /* Rewrite the url from 'balancer://url'
 574      * to the 'worker_scheme://worker_hostname[:worker_port]/url'
 575      * This replaces the balancers fictional name with the
 576      * real hostname of the elected worker.
 577      */
 578     access_status = rewrite_url(r, *worker, url);
 579     /* Add the session route to request notes if present */
 580     if (route) {
 581         apr_table_setn(r->notes, "session-sticky", sticky);
 582         apr_table_setn(r->notes, "session-route", route);
 583
 584         /* Add session info to env. */
 585         apr_table_setn(r->subprocess_env,
 586                        "BALANCER_SESSION_STICKY", sticky);
 587         apr_table_setn(r->subprocess_env,
 588                        "BALANCER_SESSION_ROUTE", route);
 589     }
 590     ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 591                  "proxy: BALANCER (%s) worker (%s) rewritten to %s",
 592                  (*balancer)->name, (*worker)->name, *url);
 593
 594     return access_status;
 595 }
 596
 597 static int proxy_balancer_post_request(proxy_worker *worker,
 598                                        proxy_balancer *balancer,
 599                                        request_rec *r,
 600                                        proxy_server_conf *conf)
 601 {
 602
 603     apr_status_t rv;
 604
 605     if ((rv = PROXY_THREAD_LOCK(balancer)) != APR_SUCCESS) {
 606         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 607             "proxy: BALANCER: (%s). Lock failed for post_request",
 608             balancer->name);
 609         return HTTP_INTERNAL_SERVER_ERROR;
 610     }
 611
 612     if (!apr_is_empty_array(balancer->errstatuses)) {
 613         int i;
 614         for (i = 0; i < balancer->errstatuses->nelts; i++) {
 615             int val = ((int *)balancer->errstatuses->elts)[i];
 616             if (r->status == val) {
 617                 ap_log_error(APLOG_MARK, APLOG_NOTICE, rv, r->server,
 618                     "Detected ErrorOnState (%d) for member (%s). Forcing worker into error state.", val, worker->name);
 619                 worker->s->status |= PROXY_WORKER_IN_ERROR;
 620                 worker->s->error_time = apr_time_now();
 621                 break;
 622             }
 623         }
 624     }
 625
 626     if ((rv = PROXY_THREAD_UNLOCK(balancer)) != APR_SUCCESS) {
 627         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 628             "proxy: BALANCER: (%s). Unlock failed for post_request",
 629             balancer->name);
 630     }
 631     ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 632                  "proxy_balancer_post_request for (%s)", balancer->name);
 633
 634     if (worker && worker->s->busy)
 635         worker->s->busy--;
 636
 637     return OK;
 638
 639 }
 640
 641 static void recalc_factors(proxy_balancer *balancer)
 642 {
 643     int i;
 644     proxy_worker **workers;
 645
 646
 647     /* Recalculate lbfactors */
 648     workers = (proxy_worker **)balancer->workers->elts;
 649     /* Special case if there is only one worker it's
 650      * load factor will always be 1
 651      */
 652     if (balancer->workers->nelts == 1) {
 653         (*workers)->s->lbstatus = (*workers)->s->lbfactor = 1;
 654         return;
 655     }
 656     for (i = 0; i < balancer->workers->nelts; i++) {
 657         /* Update the status entries */
 658         workers[i]->s->lbstatus = workers[i]->s->lbfactor;
 659     }
 660 }
 661
 662 /* pre_config hook: */
 663 static int balancer_init(apr_pool_t *pconf, apr_pool_t *plog,
 664                          apr_pool_t *ptemp)
 665 {
 666     apr_uuid_t uuid;
 667
 668     /* Retrieve a UUID and store the nonce for the lifetime of
 669      * the process. */
 670     apr_uuid_get(&uuid);
 671     apr_uuid_format(balancer_nonce, &uuid);
 672
 673     return OK;
 674 }
 675
 676 /* Manages the loadfactors and member status
 677  */
 678 static int balancer_handler(request_rec *r)
 679 {
 680     void *sconf = r->server->module_config;
 681     proxy_server_conf *conf = (proxy_server_conf *)
 682         ap_get_module_config(sconf, &proxy_module);
 683     proxy_balancer *balancer, *bsel = NULL;
 684     proxy_worker *worker, *wsel = NULL;
 685     proxy_worker **workers = NULL;
 686     apr_table_t *params = apr_table_make(r->pool, 10);
 687     int access_status;
 688     int i, n;
 689     const char *name;
 690
 691     /* is this for us? */
 692     if (strcmp(r->handler, "balancer-manager"))
 693         return DECLINED;
 694     r->allowed = (AP_METHOD_BIT << M_GET);
 695     if (r->method_number != M_GET)
 696         return DECLINED;
 697
 698     if (r->args) {
 699         char *args = apr_pstrdup(r->pool, r->args);
 700         char *tok, *val;
 701         while (args && *args) {
 702             if ((val = ap_strchr(args, '='))) {
 703                 *val++ = '\0';
 704                 if ((tok = ap_strchr(val, '&')))
 705                     *tok++ = '\0';
 706                 /*
 707                  * Special case: workers are allowed path information
 708                  */
 709                 if ((access_status = ap_unescape_url(val)) != OK)
 710                     if (strcmp(args, "w") || (access_status !=  HTTP_NOT_FOUND))
 711                         return access_status;
 712                 apr_table_setn(params, args, val);
 713                 args = tok;
 714             }
 715             else
 716                 return HTTP_BAD_REQUEST;
 717         }
 718     }
 719
 720     /* Check that the supplied nonce matches this server's nonce;
 721      * otherwise ignore all parameters, to prevent a CSRF attack. */
 722     if (*balancer_nonce &&
 723         ((name = apr_table_get(params, "nonce")) == NULL
 724         || strcmp(balancer_nonce, name) != 0)) {
 725         apr_table_clear(params);
 726     }
 727
 728     if ((name = apr_table_get(params, "b")))
 729         bsel = ap_proxy_get_balancer(r->pool, conf,
 730             apr_pstrcat(r->pool, "balancer://", name, NULL));
 731     if ((name = apr_table_get(params, "w"))) {
 732         proxy_worker *ws;
 733
 734         ws = ap_proxy_get_worker(r->pool, conf, name);
 735         if (bsel && ws) {
 736             workers = (proxy_worker **)bsel->workers->elts;
 737             for (n = 0; n < bsel->workers->nelts; n++) {
 738                 worker = *workers;
 739                 if (strcasecmp(worker->name, ws->name) == 0) {
 740                     wsel = worker;
 741                     break;
 742                 }
 743                 ++workers;
 744             }
 745         }
 746     }
 747     /* First set the params */
 748     /*
 749      * Note that it is not possible set the proxy_balancer because it is not
 750      * in shared memory.
 751      */
 752     if (wsel) {
 753         const char *val;
 754         if ((val = apr_table_get(params, "lf"))) {
 755             int ival = atoi(val);
 756             if (ival >= 1 && ival <= 100) {
 757                 wsel->s->lbfactor = ival;
 758                 if (bsel)
 759                     recalc_factors(bsel);
 760             }
 761         }
 762         if ((val = apr_table_get(params, "wr"))) {
 763             if (strlen(val) && strlen(val) < PROXY_WORKER_MAX_ROUTE_SIZ)
 764                 strcpy(wsel->s->route, val);
 765             else
 766                 *wsel->s->route = '\0';
 767         }
 768         if ((val = apr_table_get(params, "rr"))) {
 769             if (strlen(val) && strlen(val) < PROXY_WORKER_MAX_ROUTE_SIZ)
 770                 strcpy(wsel->s->redirect, val);
 771             else
 772                 *wsel->s->redirect = '\0';
 773         }
 774         if ((val = apr_table_get(params, "dw"))) {
 775             if (!strcasecmp(val, "Disable"))
 776                 wsel->s->status |= PROXY_WORKER_DISABLED;
 777             else if (!strcasecmp(val, "Enable"))
 778                 wsel->s->status &= ~PROXY_WORKER_DISABLED;
 779         }
 780         if ((val = apr_table_get(params, "ls"))) {
 781             int ival = atoi(val);
 782             if (ival >= 0 && ival <= 99) {
 783                 wsel->s->lbset = ival;
 784              }
 785         }
 786
 787     }
 788     if (apr_table_get(params, "xml")) {
 789         ap_set_content_type(r, "text/xml");
 790         ap_rputs("<?xml version=\"1.0\" encoding=\"UTF-8\" ?>\n", r);
 791         ap_rputs("<httpd:manager xmlns:httpd=\"http://httpd.apache.org\">\n", r);
 792         ap_rputs("  <httpd:balancers>\n", r);
 793         balancer = (proxy_balancer *)conf->balancers->elts;
 794         for (i = 0; i < conf->balancers->nelts; i++) {
 795             ap_rputs("    <httpd:balancer>\n", r);
 796             ap_rvputs(r, "      <httpd:name>", balancer->name, "</httpd:name>\n", NULL);
 797             ap_rputs("      <httpd:workers>\n", r);
 798             workers = (proxy_worker **)balancer->workers->elts;
 799             for (n = 0; n < balancer->workers->nelts; n++) {
 800                 worker = *workers;
 801                 ap_rputs("        <httpd:worker>\n", r);
 802                 ap_rvputs(r, "          <httpd:scheme>", worker->scheme,
 803                           "</httpd:scheme>\n", NULL);
 804                 ap_rvputs(r, "          <httpd:hostname>", worker->hostname,
 805                           "</httpd:hostname>\n", NULL);
 806                ap_rprintf(r, "          <httpd:loadfactor>%d</httpd:loadfactor>\n",
 807                           worker->s->lbfactor);
 808                 ap_rputs("        </httpd:worker>\n", r);
 809                 ++workers;
 810             }
 811             ap_rputs("      </httpd:workers>\n", r);
 812             ap_rputs("    </httpd:balancer>\n", r);
 813             ++balancer;
 814         }
 815         ap_rputs("  </httpd:balancers>\n", r);
 816         ap_rputs("</httpd:manager>", r);
 817     }
 818     else {
 819         ap_set_content_type(r, "text/html; charset=ISO-8859-1");
 820         ap_rputs(DOCTYPE_HTML_3_2
 821                  "<html><head><title>Balancer Manager</title></head>\n", r);
 822         ap_rputs("<body><h1>Load Balancer Manager for ", r);
 823         ap_rvputs(r, ap_get_server_name(r), "</h1>\n\n", NULL);
 824         ap_rvputs(r, "<dl><dt>Server Version: ",
 825                   ap_get_server_description(), "</dt>\n", NULL);
 826         ap_rvputs(r, "<dt>Server Built: ",
 827                   ap_get_server_built(), "\n</dt></dl>\n", NULL);
 828         balancer = (proxy_balancer *)conf->balancers->elts;
 829         for (i = 0; i < conf->balancers->nelts; i++) {
 830
 831             ap_rputs("<hr />\n<h3>LoadBalancer Status for ", r);
 832             ap_rvputs(r, balancer->name, "</h3>\n\n", NULL);
 833             ap_rputs("\n\n<table border=\"0\" style=\"text-align: left;\"><tr>"
 834                 "<th>StickySession</th><th>Timeout</th><th>FailoverAttempts</th><th>Method</th>"
 835                 "</tr>\n<tr>", r);
 836             if (balancer->sticky) {
 837                 if (strcmp(balancer->sticky, balancer->sticky_path)) {
 838                     ap_rvputs(r, "<td>", balancer->sticky, " | ",
 839                               balancer->sticky_path, NULL);
 840                 }
 841                 else {
 842                     ap_rvputs(r, "<td>", balancer->sticky, NULL);
 843                 }
 844             }
 845             else {
 846                 ap_rputs("<td> - ", r);
 847             }
 848             ap_rprintf(r, "</td><td>%" APR_TIME_T_FMT "</td>",
 849                 apr_time_sec(balancer->timeout));
 850             ap_rprintf(r, "<td>%d</td>\n", balancer->max_attempts);
 851             ap_rprintf(r, "<td>%s</td>\n",
 852                        balancer->lbmethod->name);
 853             ap_rputs("</table>\n<br />", r);
 854             ap_rputs("\n\n<table border=\"0\" style=\"text-align: left;\"><tr>"
 855                 "<th>Worker URL</th>"
 856                 "<th>Route</th><th>RouteRedir</th>"
 857                 "<th>Factor</th><th>Set</th><th>Status</th>"
 858                 "<th>Elected</th><th>To</th><th>From</th>"
 859                 "</tr>\n", r);
 860
 861             workers = (proxy_worker **)balancer->workers->elts;
 862             for (n = 0; n < balancer->workers->nelts; n++) {
 863                 char fbuf[50];
 864                 worker = *workers;
 865                 ap_rvputs(r, "<tr>\n<td><a href=\"", r->uri, "?b=",
 866                           balancer->name + sizeof("balancer://") - 1, "&w=",
 867                           ap_escape_uri(r->pool, worker->name),
 868                           "&nonce=", balancer_nonce,
 869                           "\">", NULL);
 870                 ap_rvputs(r, worker->name, "</a></td>", NULL);
 871                 ap_rvputs(r, "<td>", ap_escape_html(r->pool, worker->s->route),
 872                           NULL);
 873                 ap_rvputs(r, "</td><td>",
 874                           ap_escape_html(r->pool, worker->s->redirect), NULL);
 875                 ap_rprintf(r, "</td><td>%d</td>", worker->s->lbfactor);
 876                 ap_rprintf(r, "<td>%d</td><td>", worker->s->lbset);
 877                 if (worker->s->status & PROXY_WORKER_DISABLED)
 878                    ap_rputs("Dis ", r);
 879                 if (worker->s->status & PROXY_WORKER_IN_ERROR)
 880                    ap_rputs("Err ", r);
 881                 if (worker->s->status & PROXY_WORKER_STOPPED)
 882                    ap_rputs("Stop ", r);
 883                 if (worker->s->status & PROXY_WORKER_HOT_STANDBY)
 884                    ap_rputs("Stby ", r);
 885                 if (PROXY_WORKER_IS_USABLE(worker))
 886                     ap_rputs("Ok", r);
 887                 if (!PROXY_WORKER_IS_INITIALIZED(worker))
 888                     ap_rputs("-", r);
 889                 ap_rputs("</td>", r);
 890                 ap_rprintf(r, "<td>%" APR_SIZE_T_FMT "</td><td>", worker->s->elected);
 891                 ap_rputs(apr_strfsize(worker->s->transferred, fbuf), r);
 892                 ap_rputs("</td><td>", r);
 893                 ap_rputs(apr_strfsize(worker->s->read, fbuf), r);
 894                 ap_rputs("</td></tr>\n", r);
 895
 896                 ++workers;
 897             }
 898             ap_rputs("</table>\n", r);
 899             ++balancer;
 900         }
 901         ap_rputs("<hr />\n", r);
 902         if (wsel && bsel) {
 903             ap_rputs("<h3>Edit worker settings for ", r);
 904             ap_rvputs(r, wsel->name, "</h3>\n", NULL);
 905             ap_rvputs(r, "<form method=\"GET\" action=\"", NULL);
 906             ap_rvputs(r, r->uri, "\">\n<dl>", NULL);
 907             ap_rputs("<table><tr><td>Load factor:</td><td><input name=\"lf\" type=text ", r);
 908             ap_rprintf(r, "value=\"%d\"></td></tr>\n", wsel->s->lbfactor);
 909             ap_rputs("<tr><td>LB Set:</td><td><input name=\"ls\" type=text ", r);
 910             ap_rprintf(r, "value=\"%d\"></td></tr>\n", wsel->s->lbset);
 911             ap_rputs("<tr><td>Route:</td><td><input name=\"wr\" type=text ", r);
 912             ap_rvputs(r, "value=\"", ap_escape_html(r->pool, wsel->s->route),
 913                       NULL);
 914             ap_rputs("\"></td></tr>\n", r);
 915             ap_rputs("<tr><td>Route Redirect:</td><td><input name=\"rr\" type=text ", r);
 916             ap_rvputs(r, "value=\"", ap_escape_html(r->pool, wsel->s->redirect),
 917                       NULL);
 918             ap_rputs("\"></td></tr>\n", r);
 919             ap_rputs("<tr><td>Status:</td><td>Disabled: <input name=\"dw\" value=\"Disable\" type=radio", r);
 920             if (wsel->s->status & PROXY_WORKER_DISABLED)
 921                 ap_rputs(" checked", r);
 922             ap_rputs("> | Enabled: <input name=\"dw\" value=\"Enable\" type=radio", r);
 923             if (!(wsel->s->status & PROXY_WORKER_DISABLED))
 924                 ap_rputs(" checked", r);
 925             ap_rputs("></td></tr>\n", r);
 926             ap_rputs("<tr><td colspan=2><input type=submit value=\"Submit\"></td></tr>\n", r);
 927             ap_rvputs(r, "</table>\n<input type=hidden name=\"w\" ",  NULL);
 928             ap_rvputs(r, "value=\"", ap_escape_uri(r->pool, wsel->name), "\">\n", NULL);
 929             ap_rvputs(r, "<input type=hidden name=\"b\" ", NULL);
 930             ap_rvputs(r, "value=\"", bsel->name + sizeof("balancer://") - 1,
 931                       "\">\n", NULL);
 932             ap_rvputs(r, "<input type=hidden name=\"nonce\" value=\"",
 933                       balancer_nonce, "\">\n", NULL);
 934             ap_rvputs(r, "</form>\n", NULL);
 935             ap_rputs("<hr />\n", r);
 936         }
 937         ap_rputs(ap_psignature("",r), r);
 938         ap_rputs("</body></html>\n", r);
 939     }
 940     return OK;
 941 }
 942
 943 static void child_init(apr_pool_t *p, server_rec *s)
 944 {
 945     while (s) {
 946         void *sconf = s->module_config;
 947         proxy_server_conf *conf;
 948         proxy_balancer *balancer;
 949         int i;
 950         conf = (proxy_server_conf *)ap_get_module_config(sconf, &proxy_module);
 951
 952         /* Initialize shared scoreboard data */
 953         balancer = (proxy_balancer *)conf->balancers->elts;
 954         for (i = 0; i < conf->balancers->nelts; i++) {
 955             if (balancer->lbmethod && balancer->lbmethod->reset)
 956                balancer->lbmethod->reset(balancer, s);
 957             init_balancer_members(conf, s, balancer);
 958             balancer++;
 959         }
 960         s = s->next;
 961     }
 962
 963 }
 964
 965 static const char *set_balancer_nonce (cmd_parms *cmd, void *dummy, const char *arg,
 966                                        const char *val)
 967 {
 968     const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
 969     if (err != NULL) {
 970         return err;
 971     }
 972
 973     if (!strcasecmp(arg, "None")) {
 974         *balancer_nonce = '\0';
 975     } else if (!strcasecmp(arg, "Set")) {
 976         if (val) {
 977             apr_cpystrn(balancer_nonce, val, sizeof(balancer_nonce));
 978         } else {
 979             return "BalancerNonce Set requires an argument";
 980         }
 981     } else if (strcasecmp(arg, "Default")) {
 982         return "Bad argument for BalancerNonce: Must be 'Set', 'None' or 'Default'";
 983     }
 984     return NULL;
 985 }
 986
 987 static const command_rec balancer_cmds[] =
 988 {
 989     AP_INIT_TAKE12("BalancerNonce", set_balancer_nonce, NULL,
 990        RSRC_CONF, "Set value for balancer-manager nonce"),
 991     {NULL}
 992 };
 993
 994 static void ap_proxy_balancer_register_hook(apr_pool_t *p)
 995 {
 996     /* Only the mpm_winnt has child init hook handler.
 997      * make sure that we are called after the mpm
 998      * initializes
 999      */
1000     static const char *const aszPred[] = { "mpm_winnt.c", NULL};
1001      /* manager handler */
1002     ap_hook_pre_config(balancer_init, NULL, NULL, APR_HOOK_MIDDLE);
1003     ap_hook_handler(balancer_handler, NULL, NULL, APR_HOOK_FIRST);
1004     ap_hook_child_init(child_init, aszPred, NULL, APR_HOOK_MIDDLE);
1005     proxy_hook_pre_request(proxy_balancer_pre_request, NULL, NULL, APR_HOOK_FIRST);
1006     proxy_hook_post_request(proxy_balancer_post_request, NULL, NULL, APR_HOOK_FIRST);
1007     proxy_hook_canon_handler(proxy_balancer_canon, NULL, NULL, APR_HOOK_FIRST);
1008 }
1009
1010 module AP_MODULE_DECLARE_DATA proxy_balancer_module = {
1011     STANDARD20_MODULE_STUFF,
1012     NULL,       /* create per-directory config structure */
1013     NULL,       /* merge per-directory config structures */
1014     NULL,       /* create per-server config structure */
1015     NULL,       /* merge per-server config structures */
1016     balancer_cmds,       /* command apr_table_t */
1017     ap_proxy_balancer_register_hook /* register hooks */
1018 };