src/connection.c

   1 /* This file is part of Pazpar2.
   2    Copyright (C) Index Data
   3
   4 Pazpar2 is free software; you can redistribute it and/or modify it under
   5 the terms of the GNU General Public License as published by the Free
   6 Software Foundation; either version 2, or (at your option) any later
   7 version.
   8
   9 Pazpar2 is distributed in the hope that it will be useful, but WITHOUT ANY
  10 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12 for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with this program; if not, write to the Free Software
  16 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17
  18 */
  19
  20 /** \file connection.c
  21     \brief Z39.50 connection (low-level client)
  22 */
  23
  24 #if HAVE_CONFIG_H
  25 #include <config.h>
  26 #endif
  27
  28 #include <stdlib.h>
  29 #include <stdio.h>
  30 #include <string.h>
  31 #if HAVE_SYS_TIME_H
  32 #include <sys/time.h>
  33 #endif
  34 #if HAVE_UNISTD_H
  35 #include <unistd.h>
  36 #endif
  37
  38 #include <signal.h>
  39 #include <assert.h>
  40
  41 #include <yaz/log.h>
  42 #include <yaz/comstack.h>
  43 #include <yaz/tcpip.h>
  44 #include "connection.h"
  45 #include "session.h"
  46 #include "host.h"
  47 #include "client.h"
  48 #include "settings.h"
  49
  50 /* connection counting (1) , disable connection counting (0) */
  51 #if 1
  52 static YAZ_MUTEX g_mutex = 0;
  53 static int no_connections = 0;
  54 static int total_no_connections = 0;
  55
  56 static int connection_use(int delta)
  57 {
  58     int result;
  59     if (!g_mutex)
  60         yaz_mutex_create(&g_mutex);
  61     yaz_mutex_enter(g_mutex);
  62     no_connections += delta;
  63     result = no_connections;
  64     if (delta > 0)
  65         total_no_connections += delta;
  66     yaz_mutex_leave(g_mutex);
  67     if (delta == 0)
  68             return result;
  69     yaz_log(YLOG_LOG, "%s connections=%d", delta > 0 ? "INC" : "DEC",
  70             no_connections);
  71     return result;
  72 }
  73
  74 int connections_count(void)
  75 {
  76     return connection_use(0);
  77 }
  78
  79
  80 #else
  81 #define connection_use(x)
  82 #define connections_count(x) 0
  83 #define connections_count_total(x) 0
  84 #endif
  85
  86
  87 /** \brief Represents a physical, reusable  connection to a remote Z39.50 host
  88  */
  89 struct connection {
  90     IOCHAN iochan;
  91     ZOOM_connection link;
  92     struct host *host;
  93     struct client *client;
  94     char *zproxy;
  95     char *url;
  96     enum {
  97         Conn_Closed,
  98         Conn_Connecting,
  99         Conn_Open
 100     } state;
 101     int operation_timeout;
 102     int session_timeout;
 103     struct connection *next; // next for same host or next in free list
 104 };
 105
 106 static int connection_connect(struct connection *con, iochan_man_t iochan_man);
 107
 108 static int connection_is_idle(struct connection *co)
 109 {
 110     ZOOM_connection link = co->link;
 111     int event;
 112
 113     if (co->state != Conn_Open || !link)
 114         return 0;
 115
 116     if (!ZOOM_connection_is_idle(link))
 117         return 0;
 118     event = ZOOM_connection_peek_event(link);
 119     if (event == ZOOM_EVENT_NONE)
 120         return 1;
 121     else
 122         return 0;
 123 }
 124
 125 ZOOM_connection connection_get_link(struct connection *co)
 126 {
 127     return co->link;
 128 }
 129
 130 static void remove_connection_from_host(struct connection *con)
 131 {
 132     struct connection **conp = &con->host->connections;
 133     assert(con);
 134     while (*conp)
 135     {
 136         if (*conp == con)
 137         {
 138             *conp = (*conp)->next;
 139             break;
 140         }
 141         conp = &(*conp)->next;
 142     }
 143     yaz_cond_broadcast(con->host->cond_ready);
 144 }
 145
 146 // Close connection and recycle structure
 147 static void connection_destroy(struct connection *co)
 148 {
 149     if (co->link)
 150     {
 151         ZOOM_connection_destroy(co->link);
 152         iochan_destroy(co->iochan);
 153     }
 154     yaz_log(YLOG_DEBUG, "%p Connection destroy %s", co, co->url);
 155
 156     if (co->client)
 157     {
 158         client_disconnect(co->client);
 159     }
 160
 161     xfree(co->zproxy);
 162     xfree(co->url);
 163     xfree(co);
 164     connection_use(-1);
 165 }
 166
 167 // Creates a new connection for client, associated with the host of
 168 // client's database
 169 static struct connection *connection_create(struct client *cl,
 170                                             const char *url,
 171                                             struct host *host,
 172                                             int operation_timeout,
 173                                             int session_timeout,
 174                                             iochan_man_t iochan_man)
 175 {
 176     struct connection *co;
 177
 178     co = xmalloc(sizeof(*co));
 179     co->host = host;
 180
 181     co->client = cl;
 182     co->url = xstrdup(url);
 183     co->zproxy = 0;
 184     client_set_connection(cl, co);
 185     co->link = 0;
 186     co->state = Conn_Closed;
 187     co->operation_timeout = operation_timeout;
 188     co->session_timeout = session_timeout;
 189
 190     if (host->ipport)
 191         connection_connect(co, iochan_man);
 192
 193     yaz_mutex_enter(host->mutex);
 194     co->next = co->host->connections;
 195     co->host->connections = co;
 196     yaz_mutex_leave(host->mutex);
 197
 198     connection_use(1);
 199     return co;
 200 }
 201
 202 static void non_block_events(struct connection *co)
 203 {
 204     int got_records = 0;
 205     IOCHAN iochan = co->iochan;
 206     ZOOM_connection link = co->link;
 207     while (1)
 208     {
 209         struct client *cl = co->client;
 210         int ev;
 211         int r = ZOOM_event_nonblock(1, &link);
 212         if (!r)
 213             break;
 214         if (!cl)
 215             continue;
 216         ev = ZOOM_connection_last_event(link);
 217
 218 #if 1
 219         yaz_log(YLOG_DEBUG, "%p Connection ZOOM_EVENT_%s", co, ZOOM_get_event_str(ev));
 220 #endif
 221         switch (ev)
 222         {
 223         case ZOOM_EVENT_TIMEOUT:
 224             break;
 225         case ZOOM_EVENT_END:
 226             {
 227                 const char *error, *addinfo;
 228                 int err;
 229                 if ((err = ZOOM_connection_error(link, &error, &addinfo)))
 230                 {
 231                     struct session *se = client_get_session(cl);
 232
 233                     session_log(se, YLOG_WARN, "%s: Error %s (%s)",
 234                                 client_get_id(cl), error, addinfo);
 235                     client_set_diagnostic(cl, err, error, addinfo);
 236                     client_set_state(cl, Client_Error);
 237                 }
 238                 else
 239                 {
 240                     iochan_settimeout(iochan, co->session_timeout);
 241                     client_set_state(cl, Client_Idle);
 242                 }
 243                 yaz_cond_broadcast(co->host->cond_ready);
 244             }
 245             break;
 246         case ZOOM_EVENT_SEND_DATA:
 247             break;
 248         case ZOOM_EVENT_RECV_DATA:
 249             break;
 250         case ZOOM_EVENT_UNKNOWN:
 251             break;
 252         case ZOOM_EVENT_SEND_APDU:
 253             client_set_state(co->client, Client_Working);
 254             iochan_settimeout(iochan, co->operation_timeout);
 255             break;
 256         case ZOOM_EVENT_RECV_APDU:
 257             break;
 258         case ZOOM_EVENT_CONNECT:
 259             co->state = Conn_Open;
 260             break;
 261         case ZOOM_EVENT_RECV_SEARCH:
 262             client_search_response(cl);
 263             break;
 264         case ZOOM_EVENT_RECV_RECORD:
 265             client_record_response(cl, &got_records);
 266             break;
 267         default:
 268             yaz_log(YLOG_LOG, "Unhandled event (%d) from %s",
 269                     ev, client_get_id(cl));
 270             break;
 271         }
 272     }
 273     if (got_records)
 274     {
 275         struct client *cl = co->client;
 276         if (cl)
 277         {
 278             client_check_preferred_watch(cl);
 279             client_got_records(cl);
 280         }
 281     }
 282 }
 283
 284 void connection_continue(struct connection *co)
 285 {
 286     int r = ZOOM_connection_exec_task(co->link);
 287     if (!r)
 288     {
 289         struct client *cl = co->client;
 290
 291         client_lock(cl);
 292         non_block_events(co);
 293         client_unlock(cl);
 294     }
 295     else
 296     {
 297         iochan_setflags(co->iochan, ZOOM_connection_get_mask(co->link));
 298         iochan_setfd(co->iochan, ZOOM_connection_get_socket(co->link));
 299     }
 300 }
 301
 302 static void connection_handler(IOCHAN iochan, int event)
 303 {
 304     struct connection *co = iochan_getdata(iochan);
 305     struct client *cl;
 306     struct host *host = co->host;
 307
 308     yaz_mutex_enter(host->mutex);
 309     cl = co->client;
 310     if (!cl)
 311     {
 312         /* no client associated with it.. We are probably getting
 313            a closed connection from the target.. Or, perhaps, an unexpected
 314            package.. We will just close the connection */
 315         yaz_log(YLOG_LOG, "timeout connection %p event=%d", co, event);
 316         remove_connection_from_host(co);
 317         yaz_mutex_leave(host->mutex);
 318         connection_destroy(co);
 319     }
 320     else if (event & EVENT_TIMEOUT)
 321     {
 322         ZOOM_connection_fire_event_timeout(co->link);
 323         client_lock(cl);
 324         non_block_events(co);
 325         client_unlock(cl);
 326
 327         remove_connection_from_host(co);
 328         yaz_mutex_leave(host->mutex);
 329         connection_destroy(co);
 330     }
 331     else
 332     {
 333         yaz_mutex_leave(host->mutex);
 334
 335         client_lock(cl);
 336         non_block_events(co);
 337
 338         ZOOM_connection_fire_event_socket(co->link, event);
 339
 340         non_block_events(co);
 341         client_unlock(cl);
 342
 343         if (co->link)
 344         {
 345             iochan_setflags(iochan, ZOOM_connection_get_mask(co->link));
 346             iochan_setfd(iochan, ZOOM_connection_get_socket(co->link));
 347         }
 348     }
 349 }
 350
 351
 352 // Disassociate connection from client
 353 static void connection_release(struct connection *co)
 354 {
 355     struct client *cl = co->client;
 356
 357     if (!cl)
 358         return;
 359     client_set_connection(cl, 0);
 360     co->client = 0;
 361 }
 362
 363 void connect_resolver_host(struct host *host, iochan_man_t iochan_man)
 364 {
 365     struct connection *con;
 366
 367     yaz_mutex_enter(host->mutex);
 368     con = host->connections;
 369     while (con)
 370     {
 371         if (con->state == Conn_Closed)
 372         {
 373             struct client *cl = con->client;
 374             if (!host->ipport || !cl) /* unresolved or no client */
 375             {
 376                 remove_connection_from_host(con);
 377                 yaz_mutex_leave(host->mutex);
 378                 connection_destroy(con);
 379             }
 380             else
 381             {
 382                 struct session_database *sdb = client_get_database(cl);
 383                 struct session *se = client_get_session(cl);
 384                 if (sdb && se)
 385                 {
 386                     yaz_mutex_leave(host->mutex);
 387                     client_start_search(cl);
 388                 }
 389                 else
 390                 {
 391                     remove_connection_from_host(con);
 392                     yaz_mutex_leave(host->mutex);
 393                     connection_destroy(con);
 394                 }
 395             }
 396             /* start all over .. at some point it will be NULL */
 397             yaz_mutex_enter(host->mutex);
 398             con = host->connections;
 399         }
 400         else
 401         {
 402             con = con->next;
 403         }
 404     }
 405     yaz_mutex_leave(host->mutex);
 406 }
 407
 408 static struct host *connection_get_host(struct connection *con)
 409 {
 410     return con->host;
 411 }
 412
 413 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 414 {
 415     struct host *host = connection_get_host(con);
 416     ZOOM_options zoptions = ZOOM_options_create();
 417     const char *auth;
 418     const char *charset;
 419     const char *sru;
 420     const char *sru_version = 0;
 421     const char *value;
 422     WRBUF w;
 423
 424     struct session_database *sdb = client_get_database(con->client);
 425     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 426     const char *memcached = session_setting_oneval(sdb, PZ_MEMCACHED);
 427     const char *redis = session_setting_oneval(sdb, PZ_REDIS);
 428
 429     assert(con);
 430
 431     ZOOM_options_set(zoptions, "async", "1");
 432     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
 433     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
 434
 435     if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
 436         ZOOM_options_set(zoptions, "charset", charset);
 437     if (memcached && *memcached)
 438         ZOOM_options_set(zoptions, "memcached", memcached);
 439     if (redis && *redis)
 440         ZOOM_options_set(zoptions, "redis", redis);
 441
 442     assert(host->ipport);
 443     if (host->proxy)
 444     {
 445         yaz_log(YLOG_LOG, "proxy=%s", host->ipport);
 446         ZOOM_options_set(zoptions, "proxy", host->ipport);
 447     }
 448     else
 449     {
 450         assert(host->tproxy);
 451         yaz_log(YLOG_LOG, "tproxy=%s", host->ipport);
 452         ZOOM_options_set(zoptions, "tproxy", host->ipport);
 453     }
 454
 455     if (apdulog && *apdulog)
 456         ZOOM_options_set(zoptions, "apdulog", apdulog);
 457
 458
 459     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 460         ZOOM_options_set(zoptions, "sru", sru);
 461     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 462         && *sru_version)
 463         ZOOM_options_set(zoptions, "sru_version", sru_version);
 464
 465     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 466     {
 467         /* allow splitting user and reset with a blank always */
 468         const char *cp1 = strchr(auth, ' ');
 469         if (!cp1 && sru && *sru)
 470             cp1 =  strchr(auth, '/');
 471         if (!cp1)
 472         {
 473             /* Z39.50 user/password style, or no password for SRU */
 474             ZOOM_options_set(zoptions, "user", auth);
 475         }
 476         else
 477         {
 478             /* now consider group as well */
 479             const char *cp2 = strchr(cp1 + 1, ' ');
 480
 481             ZOOM_options_setl(zoptions, "user", auth, cp1 - auth);
 482             if (!cp2)
 483                 ZOOM_options_set(zoptions, "password", cp1 + 1);
 484             else
 485             {
 486                 ZOOM_options_setl(zoptions, "group", cp1 + 1, cp2 - cp1 - 1);
 487                 ZOOM_options_set(zoptions, "password", cp2 + 1);
 488             }
 489         }
 490     }
 491
 492     value = session_setting_oneval(sdb, PZ_AUTHENTICATION_MODE);
 493     if (value && *value)
 494         ZOOM_options_set(zoptions, "authenticationMode", value);
 495
 496     if (!(con->link = ZOOM_connection_create(zoptions)))
 497     {
 498         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 499         ZOOM_options_destroy(zoptions);
 500         return -1;
 501     }
 502
 503     w = wrbuf_alloc();
 504     if (sru && *sru && !strstr(con->url, "://"))
 505         wrbuf_puts(w, "http://");
 506     if (strchr(con->url, '#'))
 507     {
 508         const char *cp = strchr(con->url, '#');
 509         wrbuf_write(w, con->url, cp - con->url);
 510     }
 511     else
 512         wrbuf_puts(w, con->url);
 513
 514     ZOOM_connection_connect(con->link, wrbuf_cstr(w), 0);
 515
 516     con->iochan = iochan_create(-1, connection_handler, 0, "connection_socket");
 517     con->state = Conn_Connecting;
 518     iochan_settimeout(con->iochan, con->operation_timeout);
 519     iochan_setdata(con->iochan, con);
 520     iochan_add(iochan_man, con->iochan);
 521
 522     client_set_state(con->client, Client_Connecting);
 523     ZOOM_options_destroy(zoptions);
 524     wrbuf_destroy(w);
 525     return 0;
 526 }
 527
 528 // Ensure that client has a connection associated
 529 int client_prep_connection(struct client *cl,
 530                            int operation_timeout, int session_timeout,
 531                            iochan_man_t iochan_man,
 532                            const struct timeval *abstime)
 533 {
 534     struct connection *co;
 535     struct session_database *sdb = client_get_database(cl);
 536     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 537     const char *url = session_setting_oneval(sdb, PZ_URL);
 538     const char *sru = session_setting_oneval(sdb, PZ_SRU);
 539     struct host *host = 0;
 540     int default_port = *sru ? 80 : 210;
 541
 542     if (zproxy && zproxy[0] == '\0')
 543         zproxy = 0;
 544
 545     if (!url || !*url)
 546         url = sdb->database->id;
 547
 548     host = find_host(client_get_session(cl)->service->server->database_hosts,
 549                      url, zproxy, default_port, iochan_man);
 550
 551     yaz_log(YLOG_DEBUG, "client_prep_connection: target=%s url=%s",
 552             client_get_id(cl), url);
 553     if (!host)
 554         return 0;
 555
 556     co = client_get_connection(cl);
 557     if (co)
 558     {
 559         assert(co->host);
 560         if (co->host == host && client_get_state(cl) == Client_Idle)
 561         {
 562             return 2;
 563         }
 564         connection_release(co);
 565         co = 0;
 566     }
 567     if (!co)
 568     {
 569         int max_connections = 0;
 570         int reuse_connections = 1;
 571         const char *v = session_setting_oneval(client_get_database(cl),
 572                                                PZ_MAX_CONNECTIONS);
 573         if (v && *v)
 574             max_connections = atoi(v);
 575
 576         v = session_setting_oneval(client_get_database(cl),
 577                 PZ_REUSE_CONNECTIONS);
 578         if (v && *v)
 579             reuse_connections = atoi(v);
 580
 581         // See if someone else has an idle connection
 582         // We should look at timestamps here to select the longest-idle connection
 583         yaz_mutex_enter(host->mutex);
 584         while (1)
 585         {
 586             int num_connections = 0;
 587             for (co = host->connections; co; co = co->next)
 588                 num_connections++;
 589             if (reuse_connections)
 590             {
 591                 for (co = host->connections; co; co = co->next)
 592                 {
 593                     if (connection_is_idle(co) &&
 594                         !strcmp(url, co->url) &&
 595                         (!co->client || client_get_state(co->client) == Client_Idle) &&
 596                         !strcmp(ZOOM_connection_option_get(co->link, "user"),
 597                                 session_setting_oneval(client_get_database(cl),
 598                                                        PZ_AUTHENTICATION)))
 599                     {
 600                         if (zproxy == 0 && co->zproxy == 0)
 601                             break;
 602                         if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 603                             break;
 604                     }
 605                 }
 606                 if (co)
 607                 {
 608                     yaz_log(YLOG_LOG, "num_connections = %d (reusing)", num_connections);
 609                     break;
 610                 }
 611             }
 612             if (max_connections <= 0 || num_connections < max_connections)
 613             {
 614                 yaz_log(YLOG_LOG, "num_connections = %d (new); max = %d",
 615                         num_connections, max_connections);
 616                 break;
 617             }
 618             yaz_log(YLOG_LOG, "num_connections = %d (waiting) max = %d",
 619                     num_connections, max_connections);
 620             if (yaz_cond_wait(host->cond_ready, host->mutex, abstime))
 621             {
 622                 yaz_log(YLOG_LOG, "out of connections %s", client_get_id(cl));
 623                 client_set_state(cl, Client_Error);
 624                 yaz_mutex_leave(host->mutex);
 625                 return 0;
 626             }
 627         }
 628         if (co)
 629         {
 630             yaz_log(YLOG_LOG,  "%p Connection reuse. state: %d", co, co->state);
 631             connection_release(co);
 632             client_set_connection(cl, co);
 633             co->client = cl;
 634             /* ensure that connection is only assigned to this client
 635                by marking the client non Idle */
 636             client_set_state(cl, Client_Working);
 637             yaz_mutex_leave(host->mutex);
 638             co->operation_timeout = operation_timeout;
 639             co->session_timeout = session_timeout;
 640             /* tells ZOOM to reconnect if necessary. Disabled becuase
 641                the ZOOM_connection_connect flushes the task queue */
 642             ZOOM_connection_connect(co->link, 0, 0);
 643         }
 644         else
 645         {
 646             yaz_mutex_leave(host->mutex);
 647             co = connection_create(cl, url, host,
 648                                    operation_timeout, session_timeout,
 649                                    iochan_man);
 650         }
 651         assert(co->host);
 652     }
 653
 654     if (co && co->link)
 655         return 1;
 656     else
 657         return 0;
 658 }
 659
 660 /*
 661  * Local variables:
 662  * c-basic-offset: 4
 663  * c-file-style: "Stroustrup"
 664  * indent-tabs-mode: nil
 665  * End:
 666  * vim: shiftwidth=4 tabstop=8 expandtab
 667  */
 668