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_date.h"
  25
  26 static const char *balancer_mutex_type = "proxy-balancer-shm";
  27 ap_slotmem_provider_t *storage = NULL;
  28
  29 module AP_MODULE_DECLARE_DATA proxy_balancer_module;
  30
  31 /*
  32  * Register our mutex type before the config is read so we
  33  * can adjust the mutex settings using the Mutex directive.
  34  */
  35 static int balancer_pre_config(apr_pool_t *pconf, apr_pool_t *plog,
  36                                apr_pool_t *ptemp)
  37 {
  38
  39     apr_status_t rv;
  40
  41     rv = ap_mutex_register(pconf, balancer_mutex_type, NULL,
  42                                APR_LOCK_DEFAULT, 0);
  43     if (rv != APR_SUCCESS) {
  44         return rv;
  45     }
  46
  47     return OK;
  48 }
  49
  50 #if 0
  51 extern void proxy_update_members(proxy_balancer **balancer, request_rec *r,
  52                                  proxy_server_conf *conf);
  53 #endif
  54
  55 static int proxy_balancer_canon(request_rec *r, char *url)
  56 {
  57     char *host, *path;
  58     char *search = NULL;
  59     const char *err;
  60     apr_port_t port = 0;
  61
  62     /* TODO: offset of BALANCER_PREFIX ?? */
  63     if (strncasecmp(url, "balancer:", 9) == 0) {
  64         url += 9;
  65     }
  66     else {
  67         return DECLINED;
  68     }
  69
  70     ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, r->server,
  71              "proxy: BALANCER: canonicalising URL %s", url);
  72
  73     /* do syntatic check.
  74      * We break the URL into host, port, path, search
  75      */
  76     err = ap_proxy_canon_netloc(r->pool, &url, NULL, NULL, &host, &port);
  77     if (err) {
  78         ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
  79                       "error parsing URL %s: %s",
  80                       url, err);
  81         return HTTP_BAD_REQUEST;
  82     }
  83     /*
  84      * now parse path/search args, according to rfc1738:
  85      * process the path. With proxy-noncanon set (by
  86      * mod_proxy) we use the raw, unparsed uri
  87      */
  88     if (apr_table_get(r->notes, "proxy-nocanon")) {
  89         path = url;   /* this is the raw path */
  90     }
  91     else {
  92         path = ap_proxy_canonenc(r->pool, url, strlen(url), enc_path, 0,
  93                                  r->proxyreq);
  94         search = r->args;
  95     }
  96     if (path == NULL)
  97         return HTTP_BAD_REQUEST;
  98
  99     r->filename = apr_pstrcat(r->pool, "proxy:", BALANCER_PREFIX, host,
 100             "/", path, (search) ? "?" : "", (search) ? search : "", NULL);
 101
 102     r->path_info = apr_pstrcat(r->pool, "/", path, NULL);
 103
 104     return OK;
 105 }
 106
 107 static void init_balancer_members(proxy_server_conf *conf, server_rec *s,
 108                                  proxy_balancer *balancer)
 109 {
 110     int i;
 111     proxy_worker **workers;
 112
 113     workers = (proxy_worker **)balancer->workers->elts;
 114
 115     for (i = 0; i < balancer->workers->nelts; i++) {
 116         int worker_is_initialized;
 117         proxy_worker *worker = *workers;
 118         ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
 119                      "Looking at %s -> %s initialized?", balancer->name, worker->s->name);
 120         worker_is_initialized = PROXY_WORKER_IS_INITIALIZED(worker);
 121         if (!worker_is_initialized) {
 122             ap_proxy_initialize_worker(worker, s, conf->pool);
 123         }
 124         ++workers;
 125     }
 126
 127     /* Set default number of attempts to the number of
 128      * workers.
 129      */
 130     if (!balancer->max_attempts_set && balancer->workers->nelts > 1) {
 131         balancer->max_attempts = balancer->workers->nelts - 1;
 132         balancer->max_attempts_set = 1;
 133     }
 134 }
 135
 136 /* Retrieve the parameter with the given name
 137  * Something like 'JSESSIONID=12345...N'
 138  */
 139 static char *get_path_param(apr_pool_t *pool, char *url,
 140                             const char *name, int scolon_sep)
 141 {
 142     char *path = NULL;
 143     char *pathdelims = "?&";
 144
 145     if (scolon_sep) {
 146         pathdelims = ";?&";
 147     }
 148     for (path = strstr(url, name); path; path = strstr(path + 1, name)) {
 149         path += strlen(name);
 150         if (*path == '=') {
 151             /*
 152              * Session path was found, get it's value
 153              */
 154             ++path;
 155             if (*path) {
 156                 char *q;
 157                 path = apr_strtok(apr_pstrdup(pool, path), pathdelims, &q);
 158                 return path;
 159             }
 160         }
 161     }
 162     return NULL;
 163 }
 164
 165 static char *get_cookie_param(request_rec *r, const char *name)
 166 {
 167     const char *cookies;
 168     const char *start_cookie;
 169
 170     if ((cookies = apr_table_get(r->headers_in, "Cookie"))) {
 171         for (start_cookie = ap_strstr_c(cookies, name); start_cookie;
 172              start_cookie = ap_strstr_c(start_cookie + 1, name)) {
 173             if (start_cookie == cookies ||
 174                 start_cookie[-1] == ';' ||
 175                 start_cookie[-1] == ',' ||
 176                 isspace(start_cookie[-1])) {
 177
 178                 start_cookie += strlen(name);
 179                 while(*start_cookie && isspace(*start_cookie))
 180                     ++start_cookie;
 181                 if (*start_cookie++ == '=' && *start_cookie) {
 182                     /*
 183                      * Session cookie was found, get it's value
 184                      */
 185                     char *end_cookie, *cookie;
 186                     cookie = apr_pstrdup(r->pool, start_cookie);
 187                     if ((end_cookie = strchr(cookie, ';')) != NULL)
 188                         *end_cookie = '\0';
 189                     if((end_cookie = strchr(cookie, ',')) != NULL)
 190                         *end_cookie = '\0';
 191                     return cookie;
 192                 }
 193             }
 194         }
 195     }
 196     return NULL;
 197 }
 198
 199 /* Find the worker that has the 'route' defined
 200  */
 201 static proxy_worker *find_route_worker(proxy_balancer *balancer,
 202                                        const char *route, request_rec *r)
 203 {
 204     int i;
 205     int checking_standby;
 206     int checked_standby;
 207
 208     proxy_worker **workers;
 209
 210     checking_standby = checked_standby = 0;
 211     while (!checked_standby) {
 212         workers = (proxy_worker **)balancer->workers->elts;
 213         for (i = 0; i < balancer->workers->nelts; i++, workers++) {
 214             proxy_worker *worker = *workers;
 215             if ( (checking_standby ? !PROXY_WORKER_IS_STANDBY(worker) : PROXY_WORKER_IS_STANDBY(worker)) )
 216                 continue;
 217             if (*(worker->s->route) && strcmp(worker->s->route, route) == 0) {
 218                 if (worker && PROXY_WORKER_IS_USABLE(worker)) {
 219                     return worker;
 220                 } else {
 221                     /*
 222                      * If the worker is in error state run
 223                      * retry on that worker. It will be marked as
 224                      * operational if the retry timeout is elapsed.
 225                      * The worker might still be unusable, but we try
 226                      * anyway.
 227                      */
 228                     ap_proxy_retry_worker("BALANCER", worker, r->server);
 229                     if (PROXY_WORKER_IS_USABLE(worker)) {
 230                             return worker;
 231                     } else {
 232                         /*
 233                          * We have a worker that is unusable.
 234                          * It can be in error or disabled, but in case
 235                          * it has a redirection set use that redirection worker.
 236                          * This enables to safely remove the member from the
 237                          * balancer. Of course you will need some kind of
 238                          * session replication between those two remote.
 239                          */
 240                         if (*worker->s->redirect) {
 241                             proxy_worker *rworker = NULL;
 242                             rworker = find_route_worker(balancer, worker->s->redirect, r);
 243                             /* Check if the redirect worker is usable */
 244                             if (rworker && !PROXY_WORKER_IS_USABLE(rworker)) {
 245                                 /*
 246                                  * If the worker is in error state run
 247                                  * retry on that worker. It will be marked as
 248                                  * operational if the retry timeout is elapsed.
 249                                  * The worker might still be unusable, but we try
 250                                  * anyway.
 251                                  */
 252                                 ap_proxy_retry_worker("BALANCER", rworker, r->server);
 253                             }
 254                             if (rworker && PROXY_WORKER_IS_USABLE(rworker))
 255                                 return rworker;
 256                         }
 257                     }
 258                 }
 259             }
 260         }
 261         checked_standby = checking_standby++;
 262     }
 263     return NULL;
 264 }
 265
 266 static proxy_worker *find_session_route(proxy_balancer *balancer,
 267                                         request_rec *r,
 268                                         char **route,
 269                                         const char **sticky_used,
 270                                         char **url)
 271 {
 272     proxy_worker *worker = NULL;
 273
 274     if (!balancer->sticky)
 275         return NULL;
 276     /* Try to find the sticky route inside url */
 277     *route = get_path_param(r->pool, *url, balancer->sticky_path, balancer->scolonsep);
 278     if (*route) {
 279         ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 280                      "proxy: BALANCER: Found value %s for "
 281                      "stickysession %s", *route, balancer->sticky_path);
 282         *sticky_used =  balancer->sticky_path;
 283     }
 284     else {
 285         *route = get_cookie_param(r, balancer->sticky);
 286         if (*route) {
 287             *sticky_used =  balancer->sticky;
 288             ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 289                          "proxy: BALANCER: Found value %s for "
 290                          "stickysession %s", *route, balancer->sticky);
 291         }
 292     }
 293     /*
 294      * If we found a value for sticksession, find the first '.' within.
 295      * Everything after '.' (if present) is our route.
 296      */
 297     if ((*route) && ((*route = strchr(*route, '.')) != NULL ))
 298         (*route)++;
 299     if ((*route) && (**route)) {
 300         ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 301                                   "proxy: BALANCER: Found route %s", *route);
 302         /* We have a route in path or in cookie
 303          * Find the worker that has this route defined.
 304          */
 305         worker = find_route_worker(balancer, *route, r);
 306         if (worker && strcmp(*route, worker->s->route)) {
 307             /*
 308              * Notice that the route of the worker chosen is different from
 309              * the route supplied by the client.
 310              */
 311             apr_table_setn(r->subprocess_env, "BALANCER_ROUTE_CHANGED", "1");
 312             ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 313                          "proxy: BALANCER: Route changed from %s to %s",
 314                          *route, worker->s->route);
 315         }
 316         return worker;
 317     }
 318     else
 319         return NULL;
 320 }
 321
 322 static proxy_worker *find_best_worker(proxy_balancer *balancer,
 323                                       request_rec *r)
 324 {
 325     proxy_worker *candidate = NULL;
 326     apr_status_t rv;
 327
 328     if ((rv = PROXY_GLOBAL_LOCK(balancer)) != APR_SUCCESS) {
 329         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 330         "proxy: BALANCER: (%s). Lock failed for find_best_worker()", balancer->name);
 331         return NULL;
 332     }
 333
 334     candidate = (*balancer->lbmethod->finder)(balancer, r);
 335
 336     if (candidate)
 337         candidate->s->elected++;
 338
 339 /*
 340         PROXY_GLOBAL_UNLOCK(conf);
 341         return NULL;
 342 */
 343
 344     if ((rv = PROXY_GLOBAL_UNLOCK(balancer)) != APR_SUCCESS) {
 345         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 346         "proxy: BALANCER: (%s). Unlock failed for find_best_worker()", balancer->name);
 347     }
 348
 349     if (candidate == NULL) {
 350         /* All the workers are in error state or disabled.
 351          * If the balancer has a timeout sleep for a while
 352          * and try again to find the worker. The chances are
 353          * that some other thread will release a connection.
 354          * By default the timeout is not set, and the server
 355          * returns SERVER_BUSY.
 356          */
 357         if (balancer->timeout) {
 358             /* XXX: This can perhaps be build using some
 359              * smarter mechanism, like tread_cond.
 360              * But since the statuses can came from
 361              * different childs, use the provided algo.
 362              */
 363             apr_interval_time_t timeout = balancer->timeout;
 364             apr_interval_time_t step, tval = 0;
 365             /* Set the timeout to 0 so that we don't
 366              * end in infinite loop
 367              */
 368             balancer->timeout = 0;
 369             step = timeout / 100;
 370             while (tval < timeout) {
 371                 apr_sleep(step);
 372                 /* Try again */
 373                 if ((candidate = find_best_worker(balancer, r)))
 374                     break;
 375                 tval += step;
 376             }
 377             /* restore the timeout */
 378             balancer->timeout = timeout;
 379         }
 380     }
 381
 382     return candidate;
 383
 384 }
 385
 386 static int rewrite_url(request_rec *r, proxy_worker *worker,
 387                         char **url)
 388 {
 389     const char *scheme = strstr(*url, "://");
 390     const char *path = NULL;
 391
 392     if (scheme)
 393         path = ap_strchr_c(scheme + 3, '/');
 394
 395     /* we break the URL into host, port, uri */
 396     if (!worker) {
 397         return ap_proxyerror(r, HTTP_BAD_REQUEST, apr_pstrcat(r->pool,
 398                              "missing worker. URI cannot be parsed: ", *url,
 399                              NULL));
 400     }
 401
 402     *url = apr_pstrcat(r->pool, worker->s->name, path, NULL);
 403
 404     return OK;
 405 }
 406
 407 static void force_recovery(proxy_balancer *balancer, server_rec *s)
 408 {
 409     int i;
 410     int ok = 0;
 411     proxy_worker **worker;
 412
 413     worker = (proxy_worker **)balancer->workers->elts;
 414     for (i = 0; i < balancer->workers->nelts; i++, worker++) {
 415         if (!((*worker)->s->status & PROXY_WORKER_IN_ERROR)) {
 416             ok = 1;
 417             break;
 418         }
 419         else {
 420             /* Try if we can recover */
 421             ap_proxy_retry_worker("BALANCER", *worker, s);
 422             if (!((*worker)->s->status & PROXY_WORKER_IN_ERROR)) {
 423                 ok = 1;
 424                 break;
 425             }
 426         }
 427     }
 428     if (!ok) {
 429         /* If all workers are in error state force the recovery.
 430          */
 431         worker = (proxy_worker **)balancer->workers->elts;
 432         for (i = 0; i < balancer->workers->nelts; i++, worker++) {
 433             ++(*worker)->s->retries;
 434             (*worker)->s->status &= ~PROXY_WORKER_IN_ERROR;
 435             ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
 436                          "proxy: BALANCER: (%s). Forcing recovery for worker (%s)",
 437                          balancer->name, (*worker)->s->hostname);
 438         }
 439     }
 440 }
 441
 442 static int proxy_balancer_pre_request(proxy_worker **worker,
 443                                       proxy_balancer **balancer,
 444                                       request_rec *r,
 445                                       proxy_server_conf *conf, char **url)
 446 {
 447     int access_status;
 448     proxy_worker *runtime;
 449     char *route = NULL;
 450     const char *sticky = NULL;
 451     apr_status_t rv;
 452
 453     *worker = NULL;
 454     /* Step 1: check if the url is for us
 455      * The url we can handle starts with 'balancer://'
 456      * If balancer is already provided skip the search
 457      * for balancer, because this is failover attempt.
 458      */
 459     if (!*balancer &&
 460         !(*balancer = ap_proxy_get_balancer(r->pool, conf, *url)))
 461         return DECLINED;
 462
 463     /* Step 2: Lock the LoadBalancer
 464      * XXX: perhaps we need the process lock here
 465      */
 466     if ((rv = PROXY_GLOBAL_LOCK(*balancer)) != APR_SUCCESS) {
 467         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 468                      "proxy: BALANCER: (%s). Lock failed for pre_request",
 469                      (*balancer)->name);
 470         return DECLINED;
 471     }
 472
 473     /* Step 3: force recovery */
 474     force_recovery(*balancer, r->server);
 475
 476     /* Step 3.5: Update member list for the balancer */
 477     /* TODO: Implement as provider! */
 478     /* proxy_update_members(balancer, r, conf); */
 479
 480     /* Step 4: find the session route */
 481     runtime = find_session_route(*balancer, r, &route, &sticky, url);
 482     if (runtime) {
 483         if ((*balancer)->lbmethod && (*balancer)->lbmethod->updatelbstatus) {
 484             /* Call the LB implementation */
 485             (*balancer)->lbmethod->updatelbstatus(*balancer, runtime, r->server);
 486         }
 487         else { /* Use the default one */
 488             int i, total_factor = 0;
 489             proxy_worker **workers;
 490             /* We have a sticky load balancer
 491              * Update the workers status
 492              * so that even session routes get
 493              * into account.
 494              */
 495             workers = (proxy_worker **)(*balancer)->workers->elts;
 496             for (i = 0; i < (*balancer)->workers->nelts; i++) {
 497                 /* Take into calculation only the workers that are
 498                  * not in error state or not disabled.
 499                  */
 500                 if (PROXY_WORKER_IS_USABLE(*workers)) {
 501                     (*workers)->s->lbstatus += (*workers)->s->lbfactor;
 502                     total_factor += (*workers)->s->lbfactor;
 503                 }
 504                 workers++;
 505             }
 506             runtime->s->lbstatus -= total_factor;
 507         }
 508         runtime->s->elected++;
 509
 510         *worker = runtime;
 511     }
 512     else if (route && (*balancer)->sticky_force) {
 513         int i, member_of = 0;
 514         proxy_worker **workers;
 515         /*
 516          * We have a route provided that doesn't match the
 517          * balancer name. See if the provider route is the
 518          * member of the same balancer in which case return 503
 519          */
 520         workers = (proxy_worker **)(*balancer)->workers->elts;
 521         for (i = 0; i < (*balancer)->workers->nelts; i++) {
 522             if (*((*workers)->s->route) && strcmp((*workers)->s->route, route) == 0) {
 523                 member_of = 1;
 524                 break;
 525             }
 526             workers++;
 527         }
 528         if (member_of) {
 529             ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
 530                          "proxy: BALANCER: (%s). All workers are in error state for route (%s)",
 531                          (*balancer)->name, route);
 532             if ((rv = PROXY_GLOBAL_UNLOCK(*balancer)) != APR_SUCCESS) {
 533                 ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 534                              "proxy: BALANCER: (%s). Unlock failed for pre_request",
 535                              (*balancer)->name);
 536             }
 537             return HTTP_SERVICE_UNAVAILABLE;
 538         }
 539     }
 540
 541     if ((rv = PROXY_GLOBAL_UNLOCK(*balancer)) != APR_SUCCESS) {
 542         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 543                      "proxy: BALANCER: (%s). Unlock failed for pre_request",
 544                      (*balancer)->name);
 545     }
 546     if (!*worker) {
 547         runtime = find_best_worker(*balancer, r);
 548         if (!runtime) {
 549             if ((*balancer)->workers->nelts) {
 550                 ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
 551                             "proxy: BALANCER: (%s). All workers are in error state",
 552                             (*balancer)->name);
 553             } else {
 554                 ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
 555                             "proxy: BALANCER: (%s). No workers in balancer",
 556                             (*balancer)->name);
 557             }
 558
 559             return HTTP_SERVICE_UNAVAILABLE;
 560         }
 561         if ((*balancer)->sticky && runtime) {
 562             /*
 563              * This balancer has sticky sessions and the client either has not
 564              * supplied any routing information or all workers for this route
 565              * including possible redirect and hotstandby workers are in error
 566              * state, but we have found another working worker for this
 567              * balancer where we can send the request. Thus notice that we have
 568              * changed the route to the backend.
 569              */
 570             apr_table_setn(r->subprocess_env, "BALANCER_ROUTE_CHANGED", "1");
 571         }
 572         *worker = runtime;
 573     }
 574
 575     (*worker)->s->busy++;
 576
 577     /* Add balancer/worker info to env. */
 578     apr_table_setn(r->subprocess_env,
 579                    "BALANCER_NAME", (*balancer)->name);
 580     apr_table_setn(r->subprocess_env,
 581                    "BALANCER_WORKER_NAME", (*worker)->s->name);
 582     apr_table_setn(r->subprocess_env,
 583                    "BALANCER_WORKER_ROUTE", (*worker)->s->route);
 584
 585     /* Rewrite the url from 'balancer://url'
 586      * to the 'worker_scheme://worker_hostname[:worker_port]/url'
 587      * This replaces the balancers fictional name with the
 588      * real hostname of the elected worker.
 589      */
 590     access_status = rewrite_url(r, *worker, url);
 591     /* Add the session route to request notes if present */
 592     if (route) {
 593         apr_table_setn(r->notes, "session-sticky", sticky);
 594         apr_table_setn(r->notes, "session-route", route);
 595
 596         /* Add session info to env. */
 597         apr_table_setn(r->subprocess_env,
 598                        "BALANCER_SESSION_STICKY", sticky);
 599         apr_table_setn(r->subprocess_env,
 600                        "BALANCER_SESSION_ROUTE", route);
 601     }
 602     ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 603                  "proxy: BALANCER (%s) worker (%s) rewritten to %s",
 604                  (*balancer)->name, (*worker)->s->name, *url);
 605
 606     return access_status;
 607 }
 608
 609 static int proxy_balancer_post_request(proxy_worker *worker,
 610                                        proxy_balancer *balancer,
 611                                        request_rec *r,
 612                                        proxy_server_conf *conf)
 613 {
 614
 615     apr_status_t rv;
 616
 617     if ((rv = PROXY_GLOBAL_LOCK(balancer)) != APR_SUCCESS) {
 618         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 619             "proxy: BALANCER: (%s). Lock failed for post_request",
 620             balancer->name);
 621         return HTTP_INTERNAL_SERVER_ERROR;
 622     }
 623
 624     if (!apr_is_empty_array(balancer->errstatuses)) {
 625         int i;
 626         for (i = 0; i < balancer->errstatuses->nelts; i++) {
 627             int val = ((int *)balancer->errstatuses->elts)[i];
 628             if (r->status == val) {
 629                 ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 630                              "proxy: BALANCER: (%s).  Forcing recovery for worker (%s), failonstatus %d",
 631                              balancer->name, worker->s->name, val);
 632                 worker->s->status |= PROXY_WORKER_IN_ERROR;
 633                 worker->s->error_time = apr_time_now();
 634                 break;
 635             }
 636         }
 637     }
 638
 639     if ((rv = PROXY_GLOBAL_UNLOCK(balancer)) != APR_SUCCESS) {
 640         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 641             "proxy: BALANCER: (%s). Unlock failed for post_request",
 642             balancer->name);
 643     }
 644     ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 645                  "proxy_balancer_post_request for (%s)", balancer->name);
 646
 647     if (worker && worker->s->busy)
 648         worker->s->busy--;
 649
 650     return OK;
 651
 652 }
 653
 654 static void recalc_factors(proxy_balancer *balancer)
 655 {
 656     int i;
 657     proxy_worker **workers;
 658
 659
 660     /* Recalculate lbfactors */
 661     workers = (proxy_worker **)balancer->workers->elts;
 662     /* Special case if there is only one worker it's
 663      * load factor will always be 1
 664      */
 665     if (balancer->workers->nelts == 1) {
 666         (*workers)->s->lbstatus = (*workers)->s->lbfactor = 1;
 667         return;
 668     }
 669     for (i = 0; i < balancer->workers->nelts; i++) {
 670         /* Update the status entries */
 671         workers[i]->s->lbstatus = workers[i]->s->lbfactor;
 672     }
 673 }
 674
 675 static apr_status_t lock_remove(void *data)
 676 {
 677     int i;
 678     proxy_balancer *balancer;
 679     server_rec *s = data;
 680     void *sconf = s->module_config;
 681     proxy_server_conf *conf = (proxy_server_conf *) ap_get_module_config(sconf, &proxy_module);
 682
 683     balancer = (proxy_balancer *)conf->balancers->elts;
 684     for (i = 0; i < conf->balancers->nelts; i++, balancer++) {
 685         if (balancer->mutex) {
 686             apr_global_mutex_destroy(balancer->mutex);
 687             balancer->mutex = NULL;
 688         }
 689     }
 690     return(0);
 691 }
 692
 693 /* post_config hook: */
 694 static int balancer_post_config(apr_pool_t *pconf, apr_pool_t *plog,
 695                          apr_pool_t *ptemp, server_rec *s)
 696 {
 697     void *data;
 698     void *sconf = s->module_config;
 699     proxy_server_conf *conf = (proxy_server_conf *) ap_get_module_config(sconf, &proxy_module);
 700     const char *userdata_key = "mod_proxy_balancer_init";
 701
 702     /* balancer_post_config() will be called twice during startup.  So, only
 703      * set up the static data the 1st time through. */
 704     apr_pool_userdata_get(&data, userdata_key, s->process->pool);
 705     if (!data) {
 706         apr_pool_userdata_set((const void *)1, userdata_key,
 707                                apr_pool_cleanup_null, s->process->pool);
 708         return OK;
 709     }
 710
 711     /*
 712      * Get worker slotmem setup
 713      */
 714     storage = ap_lookup_provider(AP_SLOTMEM_PROVIDER_GROUP, "shared", "0");
 715     if (!storage) {
 716         ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_EMERG, 0, s,
 717                      "ap_lookup_provider %s failed", AP_SLOTMEM_PROVIDER_GROUP);
 718         return !OK;
 719     }
 720     /*
 721      * Go thru each Vhost and create the shared mem slotmem for
 722      * each balancer's workers
 723      */
 724     while (s) {
 725         int i,j;
 726         apr_status_t rv;
 727         proxy_balancer *balancer;
 728         sconf = s->module_config;
 729         conf = (proxy_server_conf *)ap_get_module_config(sconf, &proxy_module);
 730
 731         /* Initialize shared scoreboard data */
 732         balancer = (proxy_balancer *)conf->balancers->elts;
 733         for (i = 0; i < conf->balancers->nelts; i++, balancer++) {
 734             proxy_worker **workers;
 735             proxy_worker *worker;
 736             ap_slotmem_instance_t *new = NULL;
 737
 738             balancer->max_workers = balancer->workers->nelts + balancer->growth;
 739             balancer->sname = ap_md5(pconf, (const unsigned char *)balancer->name);
 740
 741             /* Create global mutex */
 742             rv = ap_global_mutex_create(&(balancer->mutex), NULL, balancer_mutex_type,
 743                                         balancer->sname, s, pconf, 0);
 744             if (rv != APR_SUCCESS || !balancer->mutex) {
 745                 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s,
 746                              "mutex creation of %s : %s failed", balancer_mutex_type,
 747                              balancer->sname);
 748                 return HTTP_INTERNAL_SERVER_ERROR;
 749             }
 750
 751             apr_pool_cleanup_register(pconf, (void *)s, lock_remove,
 752                                       apr_pool_cleanup_null);
 753
 754             ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, "Doing create: %s (%s), %d, %d",
 755                          balancer->name, balancer->sname,
 756                          (int)ALIGNED_PROXY_WORKER_SHARED_SIZE,
 757                          (int)balancer->max_workers);
 758
 759             rv = storage->create(&new, balancer->sname,
 760                                  ALIGNED_PROXY_WORKER_SHARED_SIZE,
 761                                  balancer->max_workers, AP_SLOTMEM_TYPE_PREGRAB, pconf);
 762             if (rv != APR_SUCCESS) {
 763                 ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, "slotmem_create failed");
 764                 return !OK;
 765             }
 766             balancer->slot = new;
 767
 768             workers = (proxy_worker **)balancer->workers->elts;
 769             for (j = 0; j < balancer->workers->nelts; j++, workers++) {
 770                 proxy_worker_shared *shm;
 771                 unsigned int index;
 772
 773                 worker = *workers;
 774                 if ((rv = storage->grab(balancer->slot, &index)) != APR_SUCCESS) {
 775                     ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, "slotmem_grab failed");
 776                     return !OK;
 777
 778                 }
 779                 if ((rv = storage->dptr(balancer->slot, index, (void *)&shm)) != APR_SUCCESS) {
 780                     ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, "slotmem_dptr failed");
 781                     return !OK;
 782                 }
 783                 if ((rv = ap_proxy_share_worker(worker, shm, index)) != APR_SUCCESS) {
 784                     ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, "Cannot share worker");
 785                     return !OK;
 786                 }
 787             }
 788         }
 789         s = s->next;
 790     }
 791
 792     return OK;
 793 }
 794
 795 /* Manages the loadfactors and member status
 796  */
 797 static int balancer_handler(request_rec *r)
 798 {
 799     void *sconf;
 800     proxy_server_conf *conf;
 801     proxy_balancer *balancer, *bsel = NULL;
 802     proxy_worker *worker, *wsel = NULL;
 803     proxy_worker **workers = NULL;
 804     apr_table_t *params;
 805     int access_status;
 806     int i, n;
 807     const char *name;
 808
 809     /* is this for us? */
 810     if (strcmp(r->handler, "balancer-manager")) {
 811         return DECLINED;
 812     }
 813
 814     r->allowed = (AP_METHOD_BIT << M_GET);
 815     if (r->method_number != M_GET) {
 816         return DECLINED;
 817     }
 818
 819     sconf = r->server->module_config;
 820     conf = (proxy_server_conf *) ap_get_module_config(sconf, &proxy_module);
 821     params = apr_table_make(r->pool, 10);
 822
 823     if (r->args) {
 824         char *args = apr_pstrdup(r->pool, r->args);
 825         char *tok, *val;
 826         while (args && *args) {
 827             if ((val = ap_strchr(args, '='))) {
 828                 *val++ = '\0';
 829                 if ((tok = ap_strchr(val, '&')))
 830                     *tok++ = '\0';
 831                 /*
 832                  * Special case: workers are allowed path information
 833                  */
 834                 if ((access_status = ap_unescape_url(val)) != OK)
 835                     if (strcmp(args, "w") || (access_status !=  HTTP_NOT_FOUND))
 836                         return access_status;
 837                 apr_table_setn(params, args, val);
 838                 args = tok;
 839             }
 840             else
 841                 return HTTP_BAD_REQUEST;
 842         }
 843     }
 844
 845     if ((name = apr_table_get(params, "b")))
 846         bsel = ap_proxy_get_balancer(r->pool, conf,
 847             apr_pstrcat(r->pool, BALANCER_PREFIX, name, NULL));
 848
 849     if ((name = apr_table_get(params, "w"))) {
 850         wsel = ap_proxy_get_worker(r->pool, bsel, conf, name);
 851     }
 852
 853
 854     /* Check that the supplied nonce matches this server's nonce;
 855      * otherwise ignore all parameters, to prevent a CSRF attack. */
 856     if (!bsel ||
 857         (*bsel->nonce &&
 858          (
 859           (name = apr_table_get(params, "nonce")) == NULL ||
 860           strcmp(bsel->nonce, name) != 0
 861          )
 862         )
 863        ) {
 864         apr_table_clear(params);
 865     }
 866
 867     /* First set the params */
 868     /*
 869      * Note that it is not possible set the proxy_balancer because it is not
 870      * in shared memory.
 871      */
 872     if (wsel) {
 873         const char *val;
 874         if ((val = apr_table_get(params, "lf"))) {
 875             int ival = atoi(val);
 876             if (ival >= 1 && ival <= 100) {
 877                 wsel->s->lbfactor = ival;
 878                 if (bsel)
 879                     recalc_factors(bsel);
 880             }
 881         }
 882         if ((val = apr_table_get(params, "wr"))) {
 883             if (strlen(val) && strlen(val) < sizeof(wsel->s->route))
 884                 strcpy(wsel->s->route, val);
 885             else
 886                 *wsel->s->route = '\0';
 887         }
 888         if ((val = apr_table_get(params, "rr"))) {
 889             if (strlen(val) && strlen(val) < sizeof(wsel->s->redirect))
 890                 strcpy(wsel->s->redirect, val);
 891             else
 892                 *wsel->s->redirect = '\0';
 893         }
 894         if ((val = apr_table_get(params, "dw"))) {
 895             if (!strcasecmp(val, "Disable"))
 896                 wsel->s->status |= PROXY_WORKER_DISABLED;
 897             else if (!strcasecmp(val, "Enable"))
 898                 wsel->s->status &= ~PROXY_WORKER_DISABLED;
 899         }
 900         if ((val = apr_table_get(params, "ls"))) {
 901             int ival = atoi(val);
 902             if (ival >= 0 && ival <= 99) {
 903                 wsel->s->lbset = ival;
 904              }
 905         }
 906
 907     }
 908     if (apr_table_get(params, "xml")) {
 909         ap_set_content_type(r, "text/xml");
 910         ap_rputs("<?xml version=\"1.0\" encoding=\"UTF-8\" ?>\n", r);
 911         ap_rputs("<httpd:manager xmlns:httpd=\"http://httpd.apache.org\">\n", r);
 912         ap_rputs("  <httpd:balancers>\n", r);
 913         balancer = (proxy_balancer *)conf->balancers->elts;
 914         for (i = 0; i < conf->balancers->nelts; i++) {
 915             ap_rputs("    <httpd:balancer>\n", r);
 916             ap_rvputs(r, "      <httpd:name>", balancer->name, "</httpd:name>\n", NULL);
 917             ap_rputs("      <httpd:workers>\n", r);
 918             workers = (proxy_worker **)balancer->workers->elts;
 919             for (n = 0; n < balancer->workers->nelts; n++) {
 920                 worker = *workers;
 921                 ap_rputs("        <httpd:worker>\n", r);
 922                 ap_rvputs(r, "          <httpd:scheme>", worker->s->scheme,
 923                           "</httpd:scheme>\n", NULL);
 924                 ap_rvputs(r, "          <httpd:hostname>", worker->s->hostname,
 925                           "</httpd:hostname>\n", NULL);
 926                 ap_rprintf(r, "          <httpd:loadfactor>%d</httpd:loadfactor>\n",
 927                           worker->s->lbfactor);
 928                 ap_rputs("        </httpd:worker>\n", r);
 929                 ++workers;
 930             }
 931             ap_rputs("      </httpd:workers>\n", r);
 932             ap_rputs("    </httpd:balancer>\n", r);
 933             ++balancer;
 934         }
 935         ap_rputs("  </httpd:balancers>\n", r);
 936         ap_rputs("</httpd:manager>", r);
 937     }
 938     else {
 939         ap_set_content_type(r, "text/html; charset=ISO-8859-1");
 940         ap_rputs(DOCTYPE_HTML_3_2
 941                  "<html><head><title>Balancer Manager</title></head>\n", r);
 942         ap_rputs("<body><h1>Load Balancer Manager for ", r);
 943         ap_rvputs(r, ap_get_server_name(r), "</h1>\n\n", NULL);
 944         ap_rvputs(r, "<dl><dt>Server Version: ",
 945                   ap_get_server_description(), "</dt>\n", NULL);
 946         ap_rvputs(r, "<dt>Server Built: ",
 947                   ap_get_server_built(), "\n</dt></dl>\n", NULL);
 948         balancer = (proxy_balancer *)conf->balancers->elts;
 949         for (i = 0; i < conf->balancers->nelts; i++) {
 950
 951             ap_rputs("<hr />\n<h3>LoadBalancer Status for ", r);
 952             ap_rvputs(r, balancer->name, "</h3>\n\n", NULL);
 953             ap_rputs("\n\n<table border=\"0\" style=\"text-align: left;\"><tr>"
 954                 "<th>MaxMembers</th><th>StickySession</th><th>Timeout</th><th>FailoverAttempts</th><th>Method</th>"
 955                 "</tr>\n<tr>", r);
 956             ap_rprintf(r, "<td align=\"center\">%d</td>\n", balancer->max_workers);
 957             if (balancer->sticky) {
 958                 if (strcmp(balancer->sticky, balancer->sticky_path)) {
 959                     ap_rvputs(r, "<td align=\"center\">", balancer->sticky, " | ",
 960                               balancer->sticky_path, NULL);
 961                 }
 962                 else {
 963                     ap_rvputs(r, "<td align=\"center\">", balancer->sticky, NULL);
 964                 }
 965             }
 966             else {
 967                 ap_rputs("<td align=\"center\"> - ", r);
 968             }
 969             ap_rprintf(r, "</td><td align=\"center\">%" APR_TIME_T_FMT "</td>",
 970                 apr_time_sec(balancer->timeout));
 971             ap_rprintf(r, "<td align=\"center\">%d</td>\n", balancer->max_attempts);
 972             ap_rprintf(r, "<td align=\"center\">%s</td>\n",
 973                        balancer->lbmethod->name);
 974             ap_rputs("</table>\n<br />", r);
 975             ap_rputs("\n\n<table border=\"0\" style=\"text-align: left;\"><tr>"
 976                 "<th>Worker URL</th>"
 977                 "<th>Route</th><th>RouteRedir</th>"
 978                 "<th>Factor</th><th>Set</th><th>Status</th>"
 979                 "<th>Elected</th><th>To</th><th>From</th>"
 980                 "</tr>\n", r);
 981
 982             workers = (proxy_worker **)balancer->workers->elts;
 983             for (n = 0; n < balancer->workers->nelts; n++) {
 984                 char fbuf[50];
 985                 worker = *workers;
 986                 ap_rvputs(r, "<tr>\n<td><a href=\"", r->uri, "?b=",
 987                           balancer->name + sizeof(BALANCER_PREFIX) - 1, "&w=",
 988                           ap_escape_uri(r->pool, worker->s->name),
 989                           "&nonce=", balancer->nonce,
 990                           "\">", NULL);
 991                 ap_rvputs(r, worker->s->name, "</a></td>", NULL);
 992                 ap_rvputs(r, "<td align=\"center\">", ap_escape_html(r->pool, worker->s->route),
 993                           NULL);
 994                 ap_rvputs(r, "</td><td align=\"center\">",
 995                           ap_escape_html(r->pool, worker->s->redirect), NULL);
 996                 ap_rprintf(r, "</td><td align=\"center\">%d</td>", worker->s->lbfactor);
 997                 ap_rprintf(r, "<td align=\"center\">%d</td><td align=\"center\">", worker->s->lbset);
 998                 if (worker->s->status & PROXY_WORKER_DISABLED)
 999                    ap_rputs("Dis ", r);
1000                 if (worker->s->status & PROXY_WORKER_IN_ERROR)
1001                    ap_rputs("Err ", r);
1002                 if (worker->s->status & PROXY_WORKER_STOPPED)
1003                    ap_rputs("Stop ", r);
1004                 if (worker->s->status & PROXY_WORKER_HOT_STANDBY)
1005                    ap_rputs("Stby ", r);
1006                 if (PROXY_WORKER_IS_USABLE(worker))
1007                     ap_rputs("Ok", r);
1008                 if (!PROXY_WORKER_IS_INITIALIZED(worker))
1009                     ap_rputs("-", r);
1010                 ap_rputs("</td>", r);
1011                 ap_rprintf(r, "<td align=\"center\">%" APR_SIZE_T_FMT "</td><td align=\"center\">", worker->s->elected);
1012                 ap_rputs(apr_strfsize(worker->s->transferred, fbuf), r);
1013                 ap_rputs("</td><td align=\"center\">", r);
1014                 ap_rputs(apr_strfsize(worker->s->read, fbuf), r);
1015                 ap_rputs("</td></tr>\n", r);
1016
1017                 ++workers;
1018             }
1019             ap_rputs("</table>\n", r);
1020             ++balancer;
1021         }
1022         ap_rputs("<hr />\n", r);
1023         if (wsel && bsel) {
1024             ap_rputs("<h3>Edit worker settings for ", r);
1025             ap_rvputs(r, wsel->s->name, "</h3>\n", NULL);
1026             ap_rvputs(r, "<form method=\"GET\" action=\"", NULL);
1027             ap_rvputs(r, r->uri, "\">\n<dl>", NULL);
1028             ap_rputs("<table><tr><td>Load factor:</td><td><input name=\"lf\" type=text ", r);
1029             ap_rprintf(r, "value=\"%d\"></td></tr>\n", wsel->s->lbfactor);
1030             ap_rputs("<tr><td>LB Set:</td><td><input name=\"ls\" type=text ", r);
1031             ap_rprintf(r, "value=\"%d\"></td></tr>\n", wsel->s->lbset);
1032             ap_rputs("<tr><td>Route:</td><td><input name=\"wr\" type=text ", r);
1033             ap_rvputs(r, "value=\"", ap_escape_html(r->pool, wsel->s->route),
1034                       NULL);
1035             ap_rputs("\"></td></tr>\n", r);
1036             ap_rputs("<tr><td>Route Redirect:</td><td><input name=\"rr\" type=text ", r);
1037             ap_rvputs(r, "value=\"", ap_escape_html(r->pool, wsel->s->redirect),
1038                       NULL);
1039             ap_rputs("\"></td></tr>\n", r);
1040             ap_rputs("<tr><td>Status:</td><td>Disabled: <input name=\"dw\" value=\"Disable\" type=radio", r);
1041             if (wsel->s->status & PROXY_WORKER_DISABLED)
1042                 ap_rputs(" checked", r);
1043             ap_rputs("> | Enabled: <input name=\"dw\" value=\"Enable\" type=radio", r);
1044             if (!(wsel->s->status & PROXY_WORKER_DISABLED))
1045                 ap_rputs(" checked", r);
1046             ap_rputs("></td></tr>\n", r);
1047             ap_rputs("<tr><td colspan=2><input type=submit value=\"Submit\"></td></tr>\n", r);
1048             ap_rvputs(r, "</table>\n<input type=hidden name=\"w\" ",  NULL);
1049             ap_rvputs(r, "value=\"", ap_escape_uri(r->pool, wsel->s->name), "\">\n", NULL);
1050             ap_rvputs(r, "<input type=hidden name=\"b\" ", NULL);
1051             ap_rvputs(r, "value=\"", bsel->name + sizeof(BALANCER_PREFIX) - 1,
1052                       "\">\n", NULL);
1053             ap_rvputs(r, "<input type=hidden name=\"nonce\" value=\"",
1054                       bsel->nonce, "\">\n", NULL);
1055             ap_rvputs(r, "</form>\n", NULL);
1056             ap_rputs("<hr />\n", r);
1057         }
1058         ap_rputs(ap_psignature("",r), r);
1059         ap_rputs("</body></html>\n", r);
1060     }
1061     return OK;
1062 }
1063
1064 static void balancer_child_init(apr_pool_t *p, server_rec *s)
1065 {
1066     while (s) {
1067         proxy_balancer *balancer;
1068         int i;
1069         void *sconf = s->module_config;
1070         proxy_server_conf *conf = (proxy_server_conf *)ap_get_module_config(sconf, &proxy_module);
1071         apr_status_t rv;
1072
1073         balancer = (proxy_balancer *)conf->balancers->elts;
1074         for (i = 0; i < conf->balancers->nelts; i++) {
1075             apr_size_t size;
1076             unsigned int num;
1077
1078             /*
1079              * for each balancer we need to init the global
1080              * mutex and then attach to the shared worker shm
1081              */
1082             if (!balancer->mutex) {
1083                 ap_log_error(APLOG_MARK, APLOG_INFO, 0, s,
1084                              "no mutex %s: %s", balancer->name,
1085                              balancer_mutex_type);
1086                 return;
1087             }
1088
1089             /* Re-open the mutex for the child. */
1090             rv = apr_global_mutex_child_init(&(balancer->mutex),
1091                                              apr_global_mutex_lockfile(balancer->mutex),
1092                                              p);
1093             if (rv != APR_SUCCESS) {
1094                 ap_log_error(APLOG_MARK, APLOG_CRIT, rv, s,
1095                              "Failed to reopen mutex %s: %s in child",
1096                              balancer->name, balancer_mutex_type);
1097                 exit(1); /* Ugly, but what else? */
1098             }
1099
1100             /* now attach */
1101             storage->attach(&(balancer->slot), balancer->sname, &size, &num, p);
1102             if (!balancer->slot) {
1103                 ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_EMERG, 0, s, "slotmem_attach failed");
1104                 exit(1); /* Ugly, but what else? */
1105             }
1106             if (balancer->lbmethod && balancer->lbmethod->reset)
1107                balancer->lbmethod->reset(balancer, s);
1108             init_balancer_members(conf, s, balancer);
1109             balancer++;
1110         }
1111         s = s->next;
1112     }
1113
1114 }
1115
1116 static void ap_proxy_balancer_register_hook(apr_pool_t *p)
1117 {
1118     /* Only the mpm_winnt has child init hook handler.
1119      * make sure that we are called after the mpm
1120      * initializes
1121      */
1122     static const char *const aszPred[] = { "mpm_winnt.c", "mod_slotmem_shm.c", NULL};
1123      /* manager handler */
1124     ap_hook_post_config(balancer_post_config, NULL, NULL, APR_HOOK_MIDDLE);
1125     ap_hook_pre_config(balancer_pre_config, NULL, NULL, APR_HOOK_MIDDLE);
1126     ap_hook_handler(balancer_handler, NULL, NULL, APR_HOOK_FIRST);
1127     ap_hook_child_init(balancer_child_init, aszPred, NULL, APR_HOOK_MIDDLE);
1128     proxy_hook_pre_request(proxy_balancer_pre_request, NULL, NULL, APR_HOOK_FIRST);
1129     proxy_hook_post_request(proxy_balancer_post_request, NULL, NULL, APR_HOOK_FIRST);
1130     proxy_hook_canon_handler(proxy_balancer_canon, NULL, NULL, APR_HOOK_FIRST);
1131 }
1132
1133 AP_DECLARE_MODULE(proxy_balancer) = {
1134     STANDARD20_MODULE_STUFF,
1135     NULL,       /* create per-directory config structure */
1136     NULL,       /* merge per-directory config structures */
1137     NULL,       /* create per-server config structure */
1138     NULL,       /* merge per-server config structures */
1139     NULL,       /* command apr_table_t */
1140     ap_proxy_balancer_register_hook /* register hooks */
1141 };