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 #include "apr_date.h"
  26
  27 module AP_MODULE_DECLARE_DATA proxy_balancer_module;
  28
  29 static char balancer_nonce[APR_UUID_FORMATTED_LENGTH + 1];
  30
  31 #if 0
  32 extern void proxy_update_members(proxy_balancer **balancer, request_rec *r,
  33                                   proxy_server_conf *conf);
  34 #endif
  35
  36 static int proxy_balancer_canon(request_rec *r, char *url)
  37 {
  38     char *host, *path;
  39     char *search = NULL;
  40     const char *err;
  41     apr_port_t port = 0;
  42
  43     if (strncasecmp(url, "balancer:", 9) == 0) {
  44         url += 9;
  45     }
  46     else {
  47         return DECLINED;
  48     }
  49
  50     ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, r->server,
  51              "proxy: BALANCER: canonicalising URL %s", url);
  52
  53     /* do syntatic check.
  54      * We break the URL into host, port, path, search
  55      */
  56     err = ap_proxy_canon_netloc(r->pool, &url, NULL, NULL, &host, &port);
  57     if (err) {
  58         ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
  59                       "error parsing URL %s: %s",
  60                       url, err);
  61         return HTTP_BAD_REQUEST;
  62     }
  63     /*
  64      * now parse path/search args, according to rfc1738:
  65      * process the path. With proxy-noncanon set (by
  66      * mod_proxy) we use the raw, unparsed uri
  67      */
  68     if (apr_table_get(r->notes, "proxy-nocanon")) {
  69         path = url;   /* this is the raw path */
  70     }
  71     else {
  72         path = ap_proxy_canonenc(r->pool, url, strlen(url), enc_path, 0,
  73                                  r->proxyreq);
  74         search = r->args;
  75     }
  76     if (path == NULL)
  77         return HTTP_BAD_REQUEST;
  78
  79     r->filename = apr_pstrcat(r->pool, "proxy:balancer://", host,
  80             "/", path, (search) ? "?" : "", (search) ? search : "", NULL);
  81
  82     r->path_info = apr_pstrcat(r->pool, "/", path, NULL);
  83
  84     return OK;
  85 }
  86
  87 static int init_balancer_members(proxy_server_conf *conf, server_rec *s,
  88                                  proxy_balancer *balancer)
  89 {
  90     int i;
  91     proxy_worker **workers;
  92
  93     workers = (proxy_worker **)balancer->workers->elts;
  94
  95     for (i = 0; i < balancer->workers->nelts; i++) {
  96         int worker_is_initialized;
  97         worker_is_initialized = PROXY_WORKER_IS_INITIALIZED(*workers);
  98         if (!worker_is_initialized) {
  99             proxy_worker_stat *slot;
 100             /*
 101              * If the worker is not initialized check whether its scoreboard
 102              * slot is already initialized.
 103              */
 104             slot = (proxy_worker_stat *) ap_get_scoreboard_lb((*workers)->id);
 105             if (slot) {
 106                 worker_is_initialized = slot->status & PROXY_WORKER_INITIALIZED;
 107             }
 108             else {
 109                 worker_is_initialized = 0;
 110             }
 111         }
 112         ap_proxy_initialize_worker_share(conf, *workers, s);
 113         ap_proxy_initialize_worker(*workers, s, conf->pool);
 114         if (!worker_is_initialized) {
 115             /* Set to the original configuration */
 116             (*workers)->s->lbstatus = (*workers)->s->lbfactor =
 117             ((*workers)->lbfactor ? (*workers)->lbfactor : 1);
 118             (*workers)->s->lbset = (*workers)->lbset;
 119         }
 120         ++workers;
 121     }
 122
 123     /* Set default number of attempts to the number of
 124      * workers.
 125      */
 126     if (!balancer->max_attempts_set && balancer->workers->nelts > 1) {
 127         balancer->max_attempts = balancer->workers->nelts - 1;
 128         balancer->max_attempts_set = 1;
 129     }
 130     return 0;
 131 }
 132
 133 /* Retrieve the parameter with the given name
 134  * Something like 'JSESSIONID=12345...N'
 135  */
 136 static char *get_path_param(apr_pool_t *pool, char *url,
 137                             const char *name, int scolon_sep)
 138 {
 139     char *path = NULL;
 140     char *pathdelims = "?&";
 141
 142     if (scolon_sep) {
 143         pathdelims = ";?&";
 144     }
 145     for (path = strstr(url, name); path; path = strstr(path + 1, name)) {
 146         path += strlen(name);
 147         if (*path == '=') {
 148             /*
 149              * Session path was found, get it's value
 150              */
 151             ++path;
 152             if (*path) {
 153                 char *q;
 154                 path = apr_strtok(apr_pstrdup(pool, path), pathdelims, &q);
 155                 return path;
 156             }
 157         }
 158     }
 159     return NULL;
 160 }
 161
 162 static char *get_cookie_param(request_rec *r, const char *name)
 163 {
 164     const char *cookies;
 165     const char *start_cookie;
 166
 167     if ((cookies = apr_table_get(r->headers_in, "Cookie"))) {
 168         for (start_cookie = ap_strstr_c(cookies, name); start_cookie;
 169              start_cookie = ap_strstr_c(start_cookie + 1, name)) {
 170             if (start_cookie == cookies ||
 171                 start_cookie[-1] == ';' ||
 172                 start_cookie[-1] == ',' ||
 173                 isspace(start_cookie[-1])) {
 174
 175                 start_cookie += strlen(name);
 176                 while(*start_cookie && isspace(*start_cookie))
 177                     ++start_cookie;
 178                 if (*start_cookie == '=' && start_cookie[1]) {
 179                     /*
 180                      * Session cookie was found, get it's value
 181                      */
 182                     char *end_cookie, *cookie;
 183                     ++start_cookie;
 184                     cookie = apr_pstrdup(r->pool, start_cookie);
 185                     if ((end_cookie = strchr(cookie, ';')) != NULL)
 186                         *end_cookie = '\0';
 187                     if((end_cookie = strchr(cookie, ',')) != NULL)
 188                         *end_cookie = '\0';
 189                     return cookie;
 190                 }
 191             }
 192         }
 193     }
 194     return NULL;
 195 }
 196
 197 /* Find the worker that has the 'route' defined
 198  */
 199 static proxy_worker *find_route_worker(proxy_balancer *balancer,
 200                                        const char *route, request_rec *r)
 201 {
 202     int i;
 203     int checking_standby;
 204     int checked_standby;
 205
 206     proxy_worker **workers;
 207     proxy_worker *worker;
 208
 209     checking_standby = checked_standby = 0;
 210     while (!checked_standby) {
 211         workers = (proxy_worker **)balancer->workers->elts;
 212         for (i = 0; i < balancer->workers->nelts; i++, workers++) {
 213             worker = *workers;
 214             if ( (checking_standby ? !PROXY_WORKER_IS_STANDBY(worker) : PROXY_WORKER_IS_STANDBY(worker)) )
 215                 continue;
 216             if (*(worker->s->route) && strcmp(worker->s->route, route) == 0) {
 217                 if (worker && PROXY_WORKER_IS_USABLE(worker)) {
 218                     return worker;
 219                 } else {
 220                     /*
 221                      * If the worker is in error state run
 222                      * retry on that worker. It will be marked as
 223                      * operational if the retry timeout is elapsed.
 224                      * The worker might still be unusable, but we try
 225                      * anyway.
 226                      */
 227                     ap_proxy_retry_worker("BALANCER", worker, r->server);
 228                     if (PROXY_WORKER_IS_USABLE(worker)) {
 229                             return worker;
 230                     } else {
 231                         /*
 232                          * We have a worker that is unusable.
 233                          * It can be in error or disabled, but in case
 234                          * it has a redirection set use that redirection worker.
 235                          * This enables to safely remove the member from the
 236                          * balancer. Of course you will need some kind of
 237                          * session replication between those two remote.
 238                          */
 239                         if (*worker->s->redirect) {
 240                             proxy_worker *rworker = NULL;
 241                             rworker = find_route_worker(balancer, worker->s->redirect, r);
 242                             /* Check if the redirect worker is usable */
 243                             if (rworker && !PROXY_WORKER_IS_USABLE(rworker)) {
 244                                 /*
 245                                  * If the worker is in error state run
 246                                  * retry on that worker. It will be marked as
 247                                  * operational if the retry timeout is elapsed.
 248                                  * The worker might still be unusable, but we try
 249                                  * anyway.
 250                                  */
 251                                 ap_proxy_retry_worker("BALANCER", rworker, r->server);
 252                             }
 253                             if (rworker && PROXY_WORKER_IS_USABLE(rworker))
 254                                 return rworker;
 255                         }
 256                     }
 257                 }
 258             }
 259         }
 260         checked_standby = checking_standby++;
 261     }
 262     return NULL;
 263 }
 264
 265 static proxy_worker *find_session_route(proxy_balancer *balancer,
 266                                         request_rec *r,
 267                                         char **route,
 268                                         const char **sticky_used,
 269                                         char **url)
 270 {
 271     proxy_worker *worker = NULL;
 272
 273     if (!balancer->sticky)
 274         return NULL;
 275     /* Try to find the sticky route inside url */
 276     *route = get_path_param(r->pool, *url, balancer->sticky_path, balancer->scolonsep);
 277     if (*route) {
 278         ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 279                      "proxy: BALANCER: Found value %s for "
 280                      "stickysession %s", *route, balancer->sticky_path);
 281         *sticky_used =  balancer->sticky_path;
 282     }
 283     else {
 284         *route = get_cookie_param(r, balancer->sticky);
 285         if (*route) {
 286             *sticky_used =  balancer->sticky;
 287             ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 288                          "proxy: BALANCER: Found value %s for "
 289                          "stickysession %s", *route, balancer->sticky);
 290         }
 291     }
 292     /*
 293      * If we found a value for sticksession, find the first '.' within.
 294      * Everything after '.' (if present) is our route.
 295      */
 296     if ((*route) && ((*route = strchr(*route, '.')) != NULL ))
 297         (*route)++;
 298     if ((*route) && (**route)) {
 299         ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 300                                   "proxy: BALANCER: Found route %s", *route);
 301         /* We have a route in path or in cookie
 302          * Find the worker that has this route defined.
 303          */
 304         worker = find_route_worker(balancer, *route, r);
 305         if (worker && strcmp(*route, worker->s->route)) {
 306             /*
 307              * Notice that the route of the worker chosen is different from
 308              * the route supplied by the client.
 309              */
 310             apr_table_setn(r->subprocess_env, "BALANCER_ROUTE_CHANGED", "1");
 311             ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 312                          "proxy: BALANCER: Route changed from %s to %s",
 313                          *route, worker->s->route);
 314         }
 315         return worker;
 316     }
 317     else
 318         return NULL;
 319 }
 320
 321 static proxy_worker *find_best_worker(proxy_balancer *balancer,
 322                                       request_rec *r)
 323 {
 324     proxy_worker *candidate = NULL;
 325     apr_status_t rv;
 326
 327     if ((rv = PROXY_THREAD_LOCK(balancer)) != APR_SUCCESS) {
 328         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 329         "proxy: BALANCER: (%s). Lock failed for find_best_worker()", balancer->name);
 330         return NULL;
 331     }
 332
 333     candidate = (*balancer->lbmethod->finder)(balancer, r);
 334
 335     if (candidate)
 336         candidate->s->elected++;
 337
 338 /*
 339         PROXY_THREAD_UNLOCK(balancer);
 340         return NULL;
 341 */
 342
 343     if ((rv = PROXY_THREAD_UNLOCK(balancer)) != APR_SUCCESS) {
 344         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 345         "proxy: BALANCER: (%s). Unlock failed for find_best_worker()", balancer->name);
 346     }
 347
 348     if (candidate == NULL) {
 349         /* All the workers are in error state or disabled.
 350          * If the balancer has a timeout sleep for a while
 351          * and try again to find the worker. The chances are
 352          * that some other thread will release a connection.
 353          * By default the timeout is not set, and the server
 354          * returns SERVER_BUSY.
 355          */
 356 #if APR_HAS_THREADS
 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 #endif
 381     }
 382
 383     return candidate;
 384
 385 }
 386
 387 static int rewrite_url(request_rec *r, proxy_worker *worker,
 388                         char **url)
 389 {
 390     const char *scheme = strstr(*url, "://");
 391     const char *path = NULL;
 392
 393     if (scheme)
 394         path = ap_strchr_c(scheme + 3, '/');
 395
 396     /* we break the URL into host, port, uri */
 397     if (!worker) {
 398         return ap_proxyerror(r, HTTP_BAD_REQUEST, apr_pstrcat(r->pool,
 399                              "missing worker. URI cannot be parsed: ", *url,
 400                              NULL));
 401     }
 402
 403     *url = apr_pstrcat(r->pool, worker->name, path, NULL);
 404
 405     return OK;
 406 }
 407
 408 static void force_recovery(proxy_balancer *balancer, server_rec *s)
 409 {
 410     int i;
 411     int ok = 0;
 412     proxy_worker **worker;
 413
 414     worker = (proxy_worker **)balancer->workers->elts;
 415     for (i = 0; i < balancer->workers->nelts; i++, worker++) {
 416         if (!((*worker)->s->status & PROXY_WORKER_IN_ERROR)) {
 417             ok = 1;
 418             break;
 419         }
 420         else {
 421             /* Try if we can recover */
 422             ap_proxy_retry_worker("BALANCER", *worker, s);
 423             if (!((*worker)->s->status & PROXY_WORKER_IN_ERROR)) {
 424                 ok = 1;
 425                 break;
 426             }
 427         }
 428     }
 429     if (!ok) {
 430         /* If all workers are in error state force the recovery.
 431          */
 432         worker = (proxy_worker **)balancer->workers->elts;
 433         for (i = 0; i < balancer->workers->nelts; i++, worker++) {
 434             ++(*worker)->s->retries;
 435             (*worker)->s->status &= ~PROXY_WORKER_IN_ERROR;
 436             ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
 437                          "proxy: BALANCER: (%s). Forcing recovery for worker (%s)",
 438                          balancer->name, (*worker)->hostname);
 439         }
 440     }
 441 }
 442
 443 static int proxy_balancer_pre_request(proxy_worker **worker,
 444                                       proxy_balancer **balancer,
 445                                       request_rec *r,
 446                                       proxy_server_conf *conf, char **url)
 447 {
 448     int access_status;
 449     proxy_worker *runtime;
 450     char *route = NULL;
 451     const char *sticky = NULL;
 452     apr_status_t rv;
 453
 454     *worker = NULL;
 455     /* Step 1: check if the url is for us
 456      * The url we can handle starts with 'balancer://'
 457      * If balancer is already provided skip the search
 458      * for balancer, because this is failover attempt.
 459      */
 460     if (!*balancer &&
 461         !(*balancer = ap_proxy_get_balancer(r->pool, conf, *url)))
 462         return DECLINED;
 463
 464     /* Step 2: Lock the LoadBalancer
 465      * XXX: perhaps we need the process lock here
 466      */
 467     if ((rv = PROXY_THREAD_LOCK(*balancer)) != APR_SUCCESS) {
 468         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 469                      "proxy: BALANCER: (%s). Lock failed for pre_request",
 470                      (*balancer)->name);
 471         return DECLINED;
 472     }
 473
 474     /* Step 3: force recovery */
 475     force_recovery(*balancer, r->server);
 476
 477     /* Step 3.5: Update member list for the balancer */
 478     /* TODO: Implement as provider! */
 479     /* proxy_update_members(balancer, r, conf); */
 480
 481     /* Step 4: find the session route */
 482     runtime = find_session_route(*balancer, r, &route, &sticky, url);
 483     if (runtime) {
 484         if ((*balancer)->lbmethod && (*balancer)->lbmethod->updatelbstatus) {
 485             /* Call the LB implementation */
 486             (*balancer)->lbmethod->updatelbstatus(*balancer, runtime, r->server);
 487         }
 488         else { /* Use the default one */
 489             int i, total_factor = 0;
 490             proxy_worker **workers;
 491             /* We have a sticky load balancer
 492              * Update the workers status
 493              * so that even session routes get
 494              * into account.
 495              */
 496             workers = (proxy_worker **)(*balancer)->workers->elts;
 497             for (i = 0; i < (*balancer)->workers->nelts; i++) {
 498                 /* Take into calculation only the workers that are
 499                  * not in error state or not disabled.
 500                  */
 501                 if (PROXY_WORKER_IS_USABLE(*workers)) {
 502                     (*workers)->s->lbstatus += (*workers)->s->lbfactor;
 503                     total_factor += (*workers)->s->lbfactor;
 504                 }
 505                 workers++;
 506             }
 507             runtime->s->lbstatus -= total_factor;
 508         }
 509         runtime->s->elected++;
 510
 511         *worker = runtime;
 512     }
 513     else if (route && (*balancer)->sticky_force) {
 514         int i, member_of = 0;
 515         proxy_worker **workers;
 516         /*
 517          * We have a route provided that doesn't match the
 518          * balancer name. See if the provider route is the
 519          * member of the same balancer in which case return 503
 520          */
 521         workers = (proxy_worker **)(*balancer)->workers->elts;
 522         for (i = 0; i < (*balancer)->workers->nelts; i++) {
 523             if (*((*workers)->s->route) && strcmp((*workers)->s->route, route) == 0) {
 524                 member_of = 1;
 525                 break;
 526             }
 527             workers++;
 528         }
 529         if (member_of) {
 530             ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
 531                          "proxy: BALANCER: (%s). All workers are in error state for route (%s)",
 532                          (*balancer)->name, route);
 533             if ((rv = PROXY_THREAD_UNLOCK(*balancer)) != APR_SUCCESS) {
 534                 ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 535                              "proxy: BALANCER: (%s). Unlock failed for pre_request",
 536                              (*balancer)->name);
 537             }
 538             return HTTP_SERVICE_UNAVAILABLE;
 539         }
 540     }
 541
 542     if ((rv = PROXY_THREAD_UNLOCK(*balancer)) != APR_SUCCESS) {
 543         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 544                      "proxy: BALANCER: (%s). Unlock failed for pre_request",
 545                      (*balancer)->name);
 546     }
 547     if (!*worker) {
 548         runtime = find_best_worker(*balancer, r);
 549         if (!runtime) {
 550             if ((*balancer)->workers->nelts) {
 551                 ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
 552                             "proxy: BALANCER: (%s). All workers are in error state",
 553                             (*balancer)->name);
 554             } else {
 555                 ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
 556                             "proxy: BALANCER: (%s). No workers in balancer",
 557                             (*balancer)->name);
 558             }
 559
 560             return HTTP_SERVICE_UNAVAILABLE;
 561         }
 562         if ((*balancer)->sticky && runtime) {
 563             /*
 564              * This balancer has sticky sessions and the client either has not
 565              * supplied any routing information or all workers for this route
 566              * including possible redirect and hotstandby workers are in error
 567              * state, but we have found another working worker for this
 568              * balancer where we can send the request. Thus notice that we have
 569              * changed the route to the backend.
 570              */
 571             apr_table_setn(r->subprocess_env, "BALANCER_ROUTE_CHANGED", "1");
 572         }
 573         *worker = runtime;
 574     }
 575
 576     (*worker)->s->busy++;
 577
 578     /* Add balancer/worker info to env. */
 579     apr_table_setn(r->subprocess_env,
 580                    "BALANCER_NAME", (*balancer)->name);
 581     apr_table_setn(r->subprocess_env,
 582                    "BALANCER_WORKER_NAME", (*worker)->name);
 583     apr_table_setn(r->subprocess_env,
 584                    "BALANCER_WORKER_ROUTE", (*worker)->s->route);
 585
 586     /* Rewrite the url from 'balancer://url'
 587      * to the 'worker_scheme://worker_hostname[:worker_port]/url'
 588      * This replaces the balancers fictional name with the
 589      * real hostname of the elected worker.
 590      */
 591     access_status = rewrite_url(r, *worker, url);
 592     /* Add the session route to request notes if present */
 593     if (route) {
 594         apr_table_setn(r->notes, "session-sticky", sticky);
 595         apr_table_setn(r->notes, "session-route", route);
 596
 597         /* Add session info to env. */
 598         apr_table_setn(r->subprocess_env,
 599                        "BALANCER_SESSION_STICKY", sticky);
 600         apr_table_setn(r->subprocess_env,
 601                        "BALANCER_SESSION_ROUTE", route);
 602     }
 603     ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 604                  "proxy: BALANCER (%s) worker (%s) rewritten to %s",
 605                  (*balancer)->name, (*worker)->name, *url);
 606
 607     return access_status;
 608 }
 609
 610 static int proxy_balancer_post_request(proxy_worker *worker,
 611                                        proxy_balancer *balancer,
 612                                        request_rec *r,
 613                                        proxy_server_conf *conf)
 614 {
 615
 616     apr_status_t rv;
 617
 618     if ((rv = PROXY_THREAD_LOCK(balancer)) != APR_SUCCESS) {
 619         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 620             "proxy: BALANCER: (%s). Lock failed for post_request",
 621             balancer->name);
 622         return HTTP_INTERNAL_SERVER_ERROR;
 623     }
 624
 625     if (!apr_is_empty_array(balancer->errstatuses)) {
 626         int i;
 627         for (i = 0; i < balancer->errstatuses->nelts; i++) {
 628             int val = ((int *)balancer->errstatuses->elts)[i];
 629             if (r->status == val) {
 630                 ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 631                              "proxy: BALANCER: (%s).  Forcing recovery for worker (%s), failonstatus %d",
 632                              balancer->name, worker->name, val);
 633                 worker->s->status |= PROXY_WORKER_IN_ERROR;
 634                 worker->s->error_time = apr_time_now();
 635                 break;
 636             }
 637         }
 638     }
 639
 640     if ((rv = PROXY_THREAD_UNLOCK(balancer)) != APR_SUCCESS) {
 641         ap_log_error(APLOG_MARK, APLOG_ERR, rv, r->server,
 642             "proxy: BALANCER: (%s). Unlock failed for post_request",
 643             balancer->name);
 644     }
 645     ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
 646                  "proxy_balancer_post_request for (%s)", balancer->name);
 647
 648     if (worker && worker->s->busy)
 649         worker->s->busy--;
 650
 651     return OK;
 652
 653 }
 654
 655 static void recalc_factors(proxy_balancer *balancer)
 656 {
 657     int i;
 658     proxy_worker **workers;
 659
 660
 661     /* Recalculate lbfactors */
 662     workers = (proxy_worker **)balancer->workers->elts;
 663     /* Special case if there is only one worker it's
 664      * load factor will always be 1
 665      */
 666     if (balancer->workers->nelts == 1) {
 667         (*workers)->s->lbstatus = (*workers)->s->lbfactor = 1;
 668         return;
 669     }
 670     for (i = 0; i < balancer->workers->nelts; i++) {
 671         /* Update the status entries */
 672         workers[i]->s->lbstatus = workers[i]->s->lbfactor;
 673     }
 674 }
 675
 676 /* post_config hook: */
 677 static int balancer_init(apr_pool_t *p, apr_pool_t *plog,
 678                          apr_pool_t *ptemp, server_rec *s)
 679 {
 680     apr_uuid_t uuid;
 681     void *data;
 682     const char *userdata_key = "mod_proxy_balancer_init";
 683
 684     /* balancer_init() will be called twice during startup.  So, only
 685      * set up the static data the 1st time through. */
 686     apr_pool_userdata_get(&data, userdata_key, s->process->pool);
 687     if (!data) {
 688         /* Retrieve a UUID and store the nonce for the lifetime of
 689          * the process. */
 690         apr_uuid_get(&uuid);
 691         apr_uuid_format(balancer_nonce, &uuid);
 692         apr_pool_userdata_set((const void *)1, userdata_key,
 693                                apr_pool_cleanup_null, s->process->pool);
 694     }
 695     return OK;
 696 }
 697
 698 /* Manages the loadfactors and member status
 699  */
 700 static int balancer_handler(request_rec *r)
 701 {
 702     void *sconf = r->server->module_config;
 703     proxy_server_conf *conf = (proxy_server_conf *)
 704         ap_get_module_config(sconf, &proxy_module);
 705     proxy_balancer *balancer, *bsel = NULL;
 706     proxy_worker *worker, *wsel = NULL;
 707     proxy_worker **workers = NULL;
 708     apr_table_t *params = apr_table_make(r->pool, 10);
 709     int access_status;
 710     int i, n;
 711     const char *name;
 712
 713     /* is this for us? */
 714     if (strcmp(r->handler, "balancer-manager"))
 715         return DECLINED;
 716     r->allowed = (AP_METHOD_BIT << M_GET);
 717     if (r->method_number != M_GET)
 718         return DECLINED;
 719
 720     if (r->args) {
 721         char *args = apr_pstrdup(r->pool, r->args);
 722         char *tok, *val;
 723         while (args && *args) {
 724             if ((val = ap_strchr(args, '='))) {
 725                 *val++ = '\0';
 726                 if ((tok = ap_strchr(val, '&')))
 727                     *tok++ = '\0';
 728                 /*
 729                  * Special case: workers are allowed path information
 730                  */
 731                 if ((access_status = ap_unescape_url(val)) != OK)
 732                     if (strcmp(args, "w") || (access_status !=  HTTP_NOT_FOUND))
 733                         return access_status;
 734                 apr_table_setn(params, args, val);
 735                 args = tok;
 736             }
 737             else
 738                 return HTTP_BAD_REQUEST;
 739         }
 740     }
 741
 742     /* Check that the supplied nonce matches this server's nonce;
 743      * otherwise ignore all parameters, to prevent a CSRF attack. */
 744     if (*balancer_nonce &&
 745         ((name = apr_table_get(params, "nonce")) == NULL
 746         || strcmp(balancer_nonce, name) != 0)) {
 747         apr_table_clear(params);
 748     }
 749
 750     if ((name = apr_table_get(params, "b")))
 751         bsel = ap_proxy_get_balancer(r->pool, conf,
 752             apr_pstrcat(r->pool, "balancer://", name, NULL));
 753     if ((name = apr_table_get(params, "w"))) {
 754         proxy_worker *ws;
 755
 756         ws = ap_proxy_get_worker(r->pool, conf, name);
 757         if (bsel && ws) {
 758             workers = (proxy_worker **)bsel->workers->elts;
 759             for (n = 0; n < bsel->workers->nelts; n++) {
 760                 worker = *workers;
 761                 if (strcasecmp(worker->name, ws->name) == 0) {
 762                     wsel = worker;
 763                     break;
 764                 }
 765                 ++workers;
 766             }
 767         }
 768     }
 769     /* First set the params */
 770     /*
 771      * Note that it is not possible set the proxy_balancer because it is not
 772      * in shared memory.
 773      */
 774     if (wsel) {
 775         const char *val;
 776         if ((val = apr_table_get(params, "lf"))) {
 777             int ival = atoi(val);
 778             if (ival >= 1 && ival <= 100) {
 779                 wsel->s->lbfactor = ival;
 780                 if (bsel)
 781                     recalc_factors(bsel);
 782             }
 783         }
 784         if ((val = apr_table_get(params, "wr"))) {
 785             if (strlen(val) && strlen(val) < PROXY_WORKER_MAX_ROUTE_SIZ)
 786                 strcpy(wsel->s->route, val);
 787             else
 788                 *wsel->s->route = '\0';
 789         }
 790         if ((val = apr_table_get(params, "rr"))) {
 791             if (strlen(val) && strlen(val) < PROXY_WORKER_MAX_ROUTE_SIZ)
 792                 strcpy(wsel->s->redirect, val);
 793             else
 794                 *wsel->s->redirect = '\0';
 795         }
 796         if ((val = apr_table_get(params, "dw"))) {
 797             if (!strcasecmp(val, "Disable"))
 798                 wsel->s->status |= PROXY_WORKER_DISABLED;
 799             else if (!strcasecmp(val, "Enable"))
 800                 wsel->s->status &= ~PROXY_WORKER_DISABLED;
 801         }
 802         if ((val = apr_table_get(params, "ls"))) {
 803             int ival = atoi(val);
 804             if (ival >= 0 && ival <= 99) {
 805                 wsel->s->lbset = ival;
 806              }
 807         }
 808
 809     }
 810     if (apr_table_get(params, "xml")) {
 811         ap_set_content_type(r, "text/xml");
 812         ap_rputs("<?xml version=\"1.0\" encoding=\"UTF-8\" ?>\n", r);
 813         ap_rputs("<httpd:manager xmlns:httpd=\"http://httpd.apache.org\">\n", r);
 814         ap_rputs("  <httpd:balancers>\n", r);
 815         balancer = (proxy_balancer *)conf->balancers->elts;
 816         for (i = 0; i < conf->balancers->nelts; i++) {
 817             ap_rputs("    <httpd:balancer>\n", r);
 818             ap_rvputs(r, "      <httpd:name>", balancer->name, "</httpd:name>\n", NULL);
 819             ap_rputs("      <httpd:workers>\n", r);
 820             workers = (proxy_worker **)balancer->workers->elts;
 821             for (n = 0; n < balancer->workers->nelts; n++) {
 822                 worker = *workers;
 823                 ap_rputs("        <httpd:worker>\n", r);
 824                 ap_rvputs(r, "          <httpd:scheme>", worker->scheme,
 825                           "</httpd:scheme>\n", NULL);
 826                 ap_rvputs(r, "          <httpd:hostname>", worker->hostname,
 827                           "</httpd:hostname>\n", NULL);
 828                ap_rprintf(r, "          <httpd:loadfactor>%d</httpd:loadfactor>\n",
 829                           worker->s->lbfactor);
 830                 ap_rputs("        </httpd:worker>\n", r);
 831                 ++workers;
 832             }
 833             ap_rputs("      </httpd:workers>\n", r);
 834             ap_rputs("    </httpd:balancer>\n", r);
 835             ++balancer;
 836         }
 837         ap_rputs("  </httpd:balancers>\n", r);
 838         ap_rputs("</httpd:manager>", r);
 839     }
 840     else {
 841         ap_set_content_type(r, "text/html; charset=ISO-8859-1");
 842         ap_rputs(DOCTYPE_HTML_3_2
 843                  "<html><head><title>Balancer Manager</title></head>\n", r);
 844         ap_rputs("<body><h1>Load Balancer Manager for ", r);
 845         ap_rvputs(r, ap_get_server_name(r), "</h1>\n\n", NULL);
 846         ap_rvputs(r, "<dl><dt>Server Version: ",
 847                   ap_get_server_description(), "</dt>\n", NULL);
 848         ap_rvputs(r, "<dt>Server Built: ",
 849                   ap_get_server_built(), "\n</dt></dl>\n", NULL);
 850         balancer = (proxy_balancer *)conf->balancers->elts;
 851         for (i = 0; i < conf->balancers->nelts; i++) {
 852
 853             ap_rputs("<hr />\n<h3>LoadBalancer Status for ", r);
 854             ap_rvputs(r, balancer->name, "</h3>\n\n", NULL);
 855             ap_rputs("\n\n<table border=\"0\" style=\"text-align: left;\"><tr>"
 856                 "<th>StickySession</th><th>Timeout</th><th>FailoverAttempts</th><th>Method</th>"
 857                 "</tr>\n<tr>", r);
 858             if (balancer->sticky) {
 859                 if (strcmp(balancer->sticky, balancer->sticky_path)) {
 860                     ap_rvputs(r, "<td>", balancer->sticky, " | ",
 861                               balancer->sticky_path, NULL);
 862                 }
 863                 else {
 864                     ap_rvputs(r, "<td>", balancer->sticky, NULL);
 865                 }
 866             }
 867             else {
 868                 ap_rputs("<td> - ", r);
 869             }
 870             ap_rprintf(r, "</td><td>%" APR_TIME_T_FMT "</td>",
 871                 apr_time_sec(balancer->timeout));
 872             ap_rprintf(r, "<td>%d</td>\n", balancer->max_attempts);
 873             ap_rprintf(r, "<td>%s</td>\n",
 874                        balancer->lbmethod->name);
 875             ap_rputs("</table>\n<br />", r);
 876             ap_rputs("\n\n<table border=\"0\" style=\"text-align: left;\"><tr>"
 877                 "<th>Worker URL</th>"
 878                 "<th>Route</th><th>RouteRedir</th>"
 879                 "<th>Factor</th><th>Set</th><th>Status</th>"
 880                 "<th>Elected</th><th>To</th><th>From</th>"
 881                 "</tr>\n", r);
 882
 883             workers = (proxy_worker **)balancer->workers->elts;
 884             for (n = 0; n < balancer->workers->nelts; n++) {
 885                 char fbuf[50];
 886                 worker = *workers;
 887                 ap_rvputs(r, "<tr>\n<td><a href=\"", r->uri, "?b=",
 888                           balancer->name + sizeof("balancer://") - 1, "&w=",
 889                           ap_escape_uri(r->pool, worker->name),
 890                           "&nonce=", balancer_nonce,
 891                           "\">", NULL);
 892                 ap_rvputs(r, worker->name, "</a></td>", NULL);
 893                 ap_rvputs(r, "<td>", ap_escape_html(r->pool, worker->s->route),
 894                           NULL);
 895                 ap_rvputs(r, "</td><td>",
 896                           ap_escape_html(r->pool, worker->s->redirect), NULL);
 897                 ap_rprintf(r, "</td><td>%d</td>", worker->s->lbfactor);
 898                 ap_rprintf(r, "<td>%d</td><td>", worker->s->lbset);
 899                 if (worker->s->status & PROXY_WORKER_DISABLED)
 900                    ap_rputs("Dis ", r);
 901                 if (worker->s->status & PROXY_WORKER_IN_ERROR)
 902                    ap_rputs("Err ", r);
 903                 if (worker->s->status & PROXY_WORKER_STOPPED)
 904                    ap_rputs("Stop ", r);
 905                 if (worker->s->status & PROXY_WORKER_HOT_STANDBY)
 906                    ap_rputs("Stby ", r);
 907                 if (PROXY_WORKER_IS_USABLE(worker))
 908                     ap_rputs("Ok", r);
 909                 if (!PROXY_WORKER_IS_INITIALIZED(worker))
 910                     ap_rputs("-", r);
 911                 ap_rputs("</td>", r);
 912                 ap_rprintf(r, "<td>%" APR_SIZE_T_FMT "</td><td>", worker->s->elected);
 913                 ap_rputs(apr_strfsize(worker->s->transferred, fbuf), r);
 914                 ap_rputs("</td><td>", r);
 915                 ap_rputs(apr_strfsize(worker->s->read, fbuf), r);
 916                 ap_rputs("</td></tr>\n", r);
 917
 918                 ++workers;
 919             }
 920             ap_rputs("</table>\n", r);
 921             ++balancer;
 922         }
 923         ap_rputs("<hr />\n", r);
 924         if (wsel && bsel) {
 925             ap_rputs("<h3>Edit worker settings for ", r);
 926             ap_rvputs(r, wsel->name, "</h3>\n", NULL);
 927             ap_rvputs(r, "<form method=\"GET\" action=\"", NULL);
 928             ap_rvputs(r, r->uri, "\">\n<dl>", NULL);
 929             ap_rputs("<table><tr><td>Load factor:</td><td><input name=\"lf\" type=text ", r);
 930             ap_rprintf(r, "value=\"%d\"></td></tr>\n", wsel->s->lbfactor);
 931             ap_rputs("<tr><td>LB Set:</td><td><input name=\"ls\" type=text ", r);
 932             ap_rprintf(r, "value=\"%d\"></td></tr>\n", wsel->s->lbset);
 933             ap_rputs("<tr><td>Route:</td><td><input name=\"wr\" type=text ", r);
 934             ap_rvputs(r, "value=\"", ap_escape_html(r->pool, wsel->s->route),
 935                       NULL);
 936             ap_rputs("\"></td></tr>\n", r);
 937             ap_rputs("<tr><td>Route Redirect:</td><td><input name=\"rr\" type=text ", r);
 938             ap_rvputs(r, "value=\"", ap_escape_html(r->pool, wsel->s->redirect),
 939                       NULL);
 940             ap_rputs("\"></td></tr>\n", r);
 941             ap_rputs("<tr><td>Status:</td><td>Disabled: <input name=\"dw\" value=\"Disable\" type=radio", r);
 942             if (wsel->s->status & PROXY_WORKER_DISABLED)
 943                 ap_rputs(" checked", r);
 944             ap_rputs("> | Enabled: <input name=\"dw\" value=\"Enable\" type=radio", r);
 945             if (!(wsel->s->status & PROXY_WORKER_DISABLED))
 946                 ap_rputs(" checked", r);
 947             ap_rputs("></td></tr>\n", r);
 948             ap_rputs("<tr><td colspan=2><input type=submit value=\"Submit\"></td></tr>\n", r);
 949             ap_rvputs(r, "</table>\n<input type=hidden name=\"w\" ",  NULL);
 950             ap_rvputs(r, "value=\"", ap_escape_uri(r->pool, wsel->name), "\">\n", NULL);
 951             ap_rvputs(r, "<input type=hidden name=\"b\" ", NULL);
 952             ap_rvputs(r, "value=\"", bsel->name + sizeof("balancer://") - 1,
 953                       "\">\n", NULL);
 954             ap_rvputs(r, "<input type=hidden name=\"nonce\" value=\"",
 955                       balancer_nonce, "\">\n", NULL);
 956             ap_rvputs(r, "</form>\n", NULL);
 957             ap_rputs("<hr />\n", r);
 958         }
 959         ap_rputs(ap_psignature("",r), r);
 960         ap_rputs("</body></html>\n", r);
 961     }
 962     return OK;
 963 }
 964
 965 static void child_init(apr_pool_t *p, server_rec *s)
 966 {
 967     while (s) {
 968         void *sconf = s->module_config;
 969         proxy_server_conf *conf;
 970         proxy_balancer *balancer;
 971         int i;
 972         conf = (proxy_server_conf *)ap_get_module_config(sconf, &proxy_module);
 973
 974         /* Initialize shared scoreboard data */
 975         balancer = (proxy_balancer *)conf->balancers->elts;
 976         for (i = 0; i < conf->balancers->nelts; i++) {
 977             if (balancer->lbmethod && balancer->lbmethod->reset)
 978                balancer->lbmethod->reset(balancer, s);
 979             init_balancer_members(conf, s, balancer);
 980             balancer++;
 981         }
 982         s = s->next;
 983     }
 984
 985 }
 986
 987 static const char *set_balancer_nonce (cmd_parms *cmd, void *dummy, const char *arg,
 988                                        const char *val)
 989 {
 990     const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
 991     if (err != NULL) {
 992         return err;
 993     }
 994
 995     if (!strcasecmp(arg, "None")) {
 996         *balancer_nonce = '\0';
 997     } else if (!strcasecmp(arg, "Set")) {
 998         if (val) {
 999             apr_cpystrn(balancer_nonce, val, sizeof(balancer_nonce));
1000         } else {
1001             return "BalancerNonce Set requires an argument";
1002         }
1003     } else if (strcasecmp(arg, "Default")) {
1004         return "Bad argument for BalancerNonce: Must be 'Set', 'None' or 'Default'";
1005     }
1006     return NULL;
1007 }
1008
1009 static const command_rec balancer_cmds[] =
1010 {
1011     AP_INIT_TAKE12("BalancerNonce", set_balancer_nonce, NULL,
1012        RSRC_CONF, "Set value for balancer-manager nonce"),
1013     {NULL}
1014 };
1015
1016 static void ap_proxy_balancer_register_hook(apr_pool_t *p)
1017 {
1018     /* Only the mpm_winnt has child init hook handler.
1019      * make sure that we are called after the mpm
1020      * initializes
1021      */
1022     static const char *const aszPred[] = { "mpm_winnt.c", NULL};
1023      /* manager handler */
1024     ap_hook_post_config(balancer_init, NULL, NULL, APR_HOOK_MIDDLE);
1025     ap_hook_handler(balancer_handler, NULL, NULL, APR_HOOK_FIRST);
1026     ap_hook_child_init(child_init, aszPred, NULL, APR_HOOK_MIDDLE);
1027     proxy_hook_pre_request(proxy_balancer_pre_request, NULL, NULL, APR_HOOK_FIRST);
1028     proxy_hook_post_request(proxy_balancer_post_request, NULL, NULL, APR_HOOK_FIRST);
1029     proxy_hook_canon_handler(proxy_balancer_canon, NULL, NULL, APR_HOOK_FIRST);
1030 }
1031
1032 AP_DECLARE_MODULE(proxy_balancer) = {
1033     STANDARD20_MODULE_STUFF,
1034     NULL,       /* create per-directory config structure */
1035     NULL,       /* merge per-directory config structures */
1036     NULL,       /* create per-server config structure */
1037     NULL,       /* merge per-server config structures */
1038     balancer_cmds,       /* command apr_table_t */
1039     ap_proxy_balancer_register_hook /* register hooks */
1040 };