src/connection.c

   1 /* This file is part of Pazpar2.
   2    Copyright (C) 2006-2010 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
  51 /** \brief Represents a physical, reusable  connection to a remote Z39.50 host
  52  */
  53 struct connection {
  54     IOCHAN iochan;
  55     ZOOM_connection link;
  56     struct host *host;
  57     struct client *client;
  58     char *zproxy;
  59     enum {
  60         Conn_Resolving,
  61         Conn_Connecting,
  62         Conn_Open
  63     } state;
  64     int operation_timeout;
  65     int session_timeout;
  66     struct connection *next; // next for same host or next in free list
  67 };
  68
  69 static int connection_connect(struct connection *con, iochan_man_t iochan_man);
  70
  71 static int connection_is_idle(struct connection *co)
  72 {
  73     ZOOM_connection link = co->link;
  74     int event;
  75
  76     if (co->state != Conn_Open || !link)
  77         return 0;
  78
  79     if (!ZOOM_connection_is_idle(link))
  80         return 0;
  81     event = ZOOM_connection_peek_event(link);
  82     if (event == ZOOM_EVENT_NONE || event == ZOOM_EVENT_END)
  83         return 1;
  84     else
  85         return 0;
  86 }
  87
  88 ZOOM_connection connection_get_link(struct connection *co)
  89 {
  90     return co->link;
  91 }
  92
  93 static void remove_connection_from_host(struct connection *con)
  94 {
  95     struct connection **conp = &con->host->connections;
  96     assert(con);
  97     yaz_mutex_enter(con->host->mutex);
  98     while (*conp)
  99     {
 100         if (*conp == con)
 101         {
 102             *conp = (*conp)->next;
 103             break;
 104         }
 105         conp = &(*conp)->next;
 106     }
 107     yaz_mutex_leave(con->host->mutex);
 108 }
 109
 110 // Close connection and recycle structure
 111 void connection_destroy(struct connection *co)
 112 {
 113     if (co->link)
 114     {
 115         ZOOM_connection_destroy(co->link);
 116         iochan_destroy(co->iochan);
 117     }
 118     yaz_log(YLOG_DEBUG, "Connection destroy %s", co->host->hostport);
 119
 120     if (co->client)
 121     {
 122         client_disconnect(co->client);
 123     }
 124
 125     remove_connection_from_host(co);
 126     xfree(co->zproxy);
 127     xfree(co);
 128 }
 129
 130 // Creates a new connection for client, associated with the host of
 131 // client's database
 132 static struct connection *connection_create(struct client *cl,
 133                                             int operation_timeout,
 134                                             int session_timeout,
 135                                             iochan_man_t iochan_man)
 136 {
 137     struct connection *new;
 138     struct host *host = client_get_host(cl);
 139
 140     new = xmalloc(sizeof(*new));
 141     new->host = host;
 142
 143     yaz_mutex_enter(host->mutex);
 144     new->next = new->host->connections;
 145     new->host->connections = new;
 146     yaz_mutex_leave(host->mutex);
 147
 148     new->client = cl;
 149     new->zproxy = 0;
 150     client_set_connection(cl, new);
 151     new->link = 0;
 152     new->state = Conn_Resolving;
 153     new->operation_timeout = operation_timeout;
 154     new->session_timeout = session_timeout;
 155     if (host->ipport)
 156         connection_connect(new, iochan_man);
 157     return new;
 158 }
 159
 160 static void non_block_events(struct connection *co)
 161 {
 162     IOCHAN iochan = co->iochan;
 163     ZOOM_connection link = co->link;
 164     while (1)
 165     {
 166         struct client *cl = co->client;
 167         int ev;
 168         int r = ZOOM_event_nonblock(1, &link);
 169         if (!r)
 170             break;
 171         if (!cl)
 172             continue;
 173         ev = ZOOM_connection_last_event(link);
 174
 175         client_incref(cl);
 176 #if 0
 177         yaz_log(YLOG_LOG, "ZOOM_EVENT_%s", ZOOM_get_event_str(ev));
 178 #endif
 179         switch (ev)
 180         {
 181         case ZOOM_EVENT_END:
 182             {
 183                 const char *error, *addinfo;
 184                 int err;
 185                 if ((err = ZOOM_connection_error(link, &error, &addinfo)))
 186                 {
 187                     yaz_log(YLOG_LOG, "Error %s from %s",
 188                             error, client_get_url(cl));
 189                 }
 190                 iochan_settimeout(iochan, co->session_timeout);
 191                 client_set_diagnostic(cl, err);
 192                 client_set_state(cl, Client_Idle);
 193             }
 194             break;
 195         case ZOOM_EVENT_SEND_DATA:
 196             break;
 197         case ZOOM_EVENT_RECV_DATA:
 198             break;
 199         case ZOOM_EVENT_UNKNOWN:
 200             break;
 201         case ZOOM_EVENT_SEND_APDU:
 202             client_set_state(co->client, Client_Working);
 203             iochan_settimeout(iochan, co->operation_timeout);
 204             break;
 205         case ZOOM_EVENT_RECV_APDU:
 206             break;
 207         case ZOOM_EVENT_CONNECT:
 208             yaz_log(YLOG_LOG, "Connected to %s", client_get_url(cl));
 209             co->state = Conn_Open;
 210             break;
 211         case ZOOM_EVENT_RECV_SEARCH:
 212             client_search_response(cl);
 213             break;
 214         case ZOOM_EVENT_RECV_RECORD:
 215             client_record_response(cl);
 216             break;
 217         default:
 218             yaz_log(YLOG_LOG, "Unhandled event (%d) from %s",
 219                     ev, client_get_url(cl));
 220         }
 221         client_destroy(cl);
 222     }
 223 }
 224
 225 void connection_continue(struct connection *co)
 226 {
 227     non_block_events(co);
 228 }
 229
 230 static void connection_handler(IOCHAN iochan, int event)
 231 {
 232     struct connection *co = iochan_getdata(iochan);
 233     struct client *cl = co->client;
 234
 235     if (!cl)
 236     {
 237         /* no client associated with it.. We are probably getting
 238            a closed connection from the target.. Or, perhaps, an unexpected
 239            package.. We will just close the connection */
 240         connection_destroy(co);
 241         return;
 242     }
 243     if (event & EVENT_TIMEOUT)
 244     {
 245         if (co->state == Conn_Connecting)
 246         {
 247             yaz_log(YLOG_WARN,  "connect timeout %s", client_get_url(cl));
 248             client_fatal(cl);
 249         }
 250         else
 251         {
 252             yaz_log(YLOG_LOG,  "idle timeout %s", client_get_url(cl));
 253             connection_destroy(co);
 254         }
 255     }
 256     else
 257     {
 258         non_block_events(co);
 259
 260         ZOOM_connection_fire_event_socket(co->link, event);
 261
 262         non_block_events(co);
 263     }
 264 }
 265
 266
 267 // Disassociate connection from client
 268 void connection_release(struct connection *co)
 269 {
 270     struct client *cl = co->client;
 271
 272     if (!cl)
 273         return;
 274     client_set_connection(cl, 0);
 275     co->client = 0;
 276 }
 277
 278 void connect_resolver_host(struct host *host, iochan_man_t iochan_man)
 279 {
 280     struct connection *con;
 281
 282 start:
 283     yaz_mutex_enter(host->mutex);
 284     con = host->connections;
 285     while (con)
 286     {
 287         if (con->state == Conn_Resolving)
 288         {
 289             if (!host->ipport) /* unresolved */
 290             {
 291                 yaz_mutex_leave(host->mutex);
 292                 connection_destroy(con);
 293                 goto start;
 294                 /* start all over .. at some point it will be NULL */
 295             }
 296             else if (!con->client)
 297             {
 298                 yaz_mutex_leave(host->mutex);
 299                 connection_destroy(con);
 300                 /* start all over .. at some point it will be NULL */
 301                 goto start;
 302             }
 303             else
 304             {
 305                 yaz_mutex_leave(host->mutex);
 306                 connection_connect(con, iochan_man);
 307                 client_start_search(con->client);
 308                 goto start;
 309             }
 310         }
 311         else
 312         {
 313             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
 314             con = con->next;
 315         }
 316     }
 317     yaz_mutex_leave(host->mutex);
 318 }
 319
 320 static struct host *connection_get_host(struct connection *con)
 321 {
 322     return con->host;
 323 }
 324
 325 // Callback for use by event loop
 326 // We do this because ZOOM connections don't always have (the same) sockets
 327 static int socketfun(IOCHAN c)
 328 {
 329     struct connection *co = iochan_getdata(c);
 330     if (!co->link)
 331         return -1;
 332     return ZOOM_connection_get_socket(co->link);
 333 }
 334
 335 // Because ZOOM always knows what events it is interested in; we may not
 336 static int maskfun(IOCHAN c)
 337 {
 338     struct connection *co = iochan_getdata(c);
 339     if (!co->link)
 340         return 0;
 341
 342     // This is cheating a little, and assuming that eventl mask IDs are always
 343     // the same as ZOOM-C's.
 344     return ZOOM_connection_get_mask(co->link);
 345 }
 346
 347 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 348 {
 349     ZOOM_connection link = 0;
 350     struct host *host = connection_get_host(con);
 351     ZOOM_options zoptions = ZOOM_options_create();
 352     const char *auth;
 353     const char *charset;
 354     const char *sru;
 355     const char *sru_version = 0;
 356
 357     struct session_database *sdb = client_get_database(con->client);
 358     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 359     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 360
 361     assert(host->ipport);
 362     assert(con);
 363
 364     ZOOM_options_set(zoptions, "async", "1");
 365     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
 366     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
 367
 368     if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
 369         ZOOM_options_set(zoptions, "charset", charset);
 370
 371     if (zproxy && *zproxy)
 372     {
 373         con->zproxy = xstrdup(zproxy);
 374         ZOOM_options_set(zoptions, "proxy", zproxy);
 375     }
 376     if (apdulog && *apdulog)
 377         ZOOM_options_set(zoptions, "apdulog", apdulog);
 378
 379     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 380         ZOOM_options_set(zoptions, "user", auth);
 381     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 382         ZOOM_options_set(zoptions, "sru", sru);
 383     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 384         && *sru_version)
 385         ZOOM_options_set(zoptions, "sru_version", sru_version);
 386
 387     if (!(link = ZOOM_connection_create(zoptions)))
 388     {
 389         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 390         ZOOM_options_destroy(zoptions);
 391         return -1;
 392     }
 393
 394     if (sru && *sru)
 395     {
 396         char http_hostport[512];
 397         strcpy(http_hostport, "http://");
 398         strcat(http_hostport, host->hostport);
 399         ZOOM_connection_connect(link, http_hostport, 0);
 400     }
 401     else
 402         ZOOM_connection_connect(link, host->ipport, 0);
 403
 404     con->link = link;
 405     con->iochan = iochan_create(0, connection_handler, 0);
 406     con->state = Conn_Connecting;
 407     iochan_settimeout(con->iochan, con->operation_timeout);
 408     iochan_setdata(con->iochan, con);
 409     iochan_setsocketfun(con->iochan, socketfun);
 410     iochan_setmaskfun(con->iochan, maskfun);
 411     iochan_add(iochan_man, con->iochan);
 412
 413     /* this fragment is bad DRY: from client_prep_connection */
 414     client_set_state(con->client, Client_Connecting);
 415     ZOOM_options_destroy(zoptions);
 416     return 0;
 417 }
 418
 419 const char *connection_get_url(struct connection *co)
 420 {
 421     return client_get_url(co->client);
 422 }
 423
 424 // Ensure that client has a connection associated
 425 int client_prep_connection(struct client *cl,
 426                            int operation_timeout, int session_timeout,
 427                            iochan_man_t iochan_man)
 428 {
 429     struct connection *co;
 430     struct host *host = client_get_host(cl);
 431     struct session_database *sdb = client_get_database(cl);
 432     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 433
 434     if (zproxy && zproxy[0] == '\0')
 435         zproxy = 0;
 436
 437     if (!host)
 438         return 0;
 439
 440     co = client_get_connection(cl);
 441
 442     yaz_log(YLOG_DEBUG, "Client prep %s", client_get_url(cl));
 443
 444     if (!co)
 445     {
 446         // See if someone else has an idle connection
 447         // We should look at timestamps here to select the longest-idle connection
 448         yaz_mutex_enter(host->mutex);
 449         for (co = host->connections; co; co = co->next)
 450             if (connection_is_idle(co) &&
 451                 (!co->client || client_get_state(co->client) == Client_Idle) &&
 452                 !strcmp(ZOOM_connection_option_get(co->link, "user"),
 453                         session_setting_oneval(client_get_database(cl),
 454                                                PZ_AUTHENTICATION)))
 455             {
 456                 if (zproxy == 0 && co->zproxy == 0)
 457                     break;
 458                 if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 459                     break;
 460             }
 461         if (co)
 462         {
 463             connection_release(co);
 464             client_set_connection(cl, co);
 465             co->client = cl;
 466             yaz_mutex_leave(host->mutex);
 467             co->operation_timeout = operation_timeout;
 468             co->session_timeout = session_timeout;
 469             /* tells ZOOM to reconnect if necessary. Disabled becuase
 470                the ZOOM_connection_connect flushes the task queue */
 471             ZOOM_connection_connect(co->link, 0, 0);
 472         }
 473         else
 474         {
 475             yaz_mutex_leave(host->mutex);
 476             co = connection_create(cl, operation_timeout, session_timeout,
 477                                    iochan_man);
 478         }
 479     }
 480
 481     if (co && co->link)
 482         return 1;
 483     else
 484         return 0;
 485 }
 486
 487 /*
 488  * Local variables:
 489  * c-basic-offset: 4
 490  * c-file-style: "Stroustrup"
 491  * indent-tabs-mode: nil
 492  * End:
 493  * vim: shiftwidth=4 tabstop=8 expandtab
 494  */
 495