src/connection.c

   1 /* This file is part of Pazpar2.
   2    Copyright (C) 2006-2008 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 #if HAVE_SYS_SOCKET_H
  38 #include <sys/socket.h>
  39 #endif
  40 #ifdef WIN32
  41 #include <winsock.h>
  42 typedef int socklen_t;
  43 #endif
  44 #if HAVE_NETDB_H
  45 #include <netdb.h>
  46 #endif
  47
  48 #include <signal.h>
  49 #include <ctype.h>
  50 #include <assert.h>
  51
  52 #include <yaz/log.h>
  53 #include <yaz/comstack.h>
  54 #include <yaz/tcpip.h>
  55 #include "connection.h"
  56 #include "eventl.h"
  57 #include "pazpar2.h"
  58 #include "host.h"
  59 #include "client.h"
  60 #include "settings.h"
  61 #include "parameters.h"
  62
  63
  64 /** \brief Represents a physical, reusable  connection to a remote Z39.50 host
  65  */
  66 struct connection {
  67     IOCHAN iochan;
  68     COMSTACK link;
  69     struct host *host;
  70     struct client *client;
  71     char *ibuf;
  72     int ibufsize;
  73     char *authentication; // Empty string or authentication string if set
  74     char *zproxy;
  75     enum {
  76         Conn_Resolving,
  77         Conn_Connecting,
  78         Conn_Open,
  79         Conn_Waiting,
  80     } state;
  81     struct connection *next; // next for same host or next in free list
  82 };
  83
  84 static struct connection *connection_freelist = 0;
  85
  86 static void remove_connection_from_host(struct connection *con)
  87 {
  88     struct connection **conp = &con->host->connections;
  89     assert(con);
  90     while (*conp)
  91     {
  92         if (*conp == con)
  93         {
  94             *conp = (*conp)->next;
  95             return;
  96         }
  97         conp = &(*conp)->next;
  98     }
  99     assert(*conp == 0);
 100 }
 101
 102 // Close connection and recycle structure
 103 void connection_destroy(struct connection *co)
 104 {
 105     if (co->link)
 106     {
 107         cs_close(co->link);
 108         iochan_destroy(co->iochan);
 109     }
 110
 111     yaz_log(YLOG_DEBUG, "Connection destroy %s", co->host->hostport);
 112
 113     remove_connection_from_host(co);
 114     if (co->client)
 115     {
 116         client_disconnect(co->client);
 117     }
 118     xfree(co->zproxy);
 119     co->zproxy = 0;
 120     co->next = connection_freelist;
 121     connection_freelist = co;
 122 }
 123
 124 // Creates a new connection for client, associated with the host of
 125 // client's database
 126 struct connection *connection_create(struct client *cl)
 127 {
 128     struct connection *new;
 129     struct host *host = client_get_host(cl);
 130
 131     if ((new = connection_freelist))
 132         connection_freelist = new->next;
 133     else
 134     {
 135         new = xmalloc(sizeof (struct connection));
 136         new->ibuf = 0;
 137         new->ibufsize = 0;
 138     }
 139     new->host = host;
 140     new->next = new->host->connections;
 141     new->host->connections = new;
 142     new->client = cl;
 143     new->authentication = "";
 144     new->zproxy = 0;
 145     client_set_connection(cl, new);
 146     new->link = 0;
 147     new->state = Conn_Resolving;
 148     if (host->ipport)
 149         connection_connect(new);
 150     return new;
 151 }
 152
 153 static void connection_handler(IOCHAN i, int event)
 154 {
 155     struct connection *co = iochan_getdata(i);
 156     struct client *cl = co->client;
 157     struct session *se = 0;
 158
 159     if (cl)
 160         se = client_get_session(cl);
 161     else
 162     {
 163         connection_destroy(co);
 164         return;
 165     }
 166
 167     if (event & EVENT_TIMEOUT)
 168     {
 169         if (co->state == Conn_Connecting)
 170         {
 171             yaz_log(YLOG_WARN,  "connect timeout %s", client_get_url(cl));
 172             client_fatal(cl);
 173         }
 174         else
 175         {
 176             yaz_log(YLOG_LOG,  "idle timeout %s", client_get_url(cl));
 177             connection_destroy(co);
 178         }
 179         return;
 180     }
 181     if (co->state == Conn_Connecting && event & EVENT_OUTPUT)
 182     {
 183         int errcode;
 184         socklen_t errlen = sizeof(errcode);
 185
 186         if (getsockopt(cs_fileno(co->link), SOL_SOCKET, SO_ERROR, (char*) &errcode,
 187             &errlen) < 0 || errcode != 0)
 188         {
 189             client_fatal(cl);
 190             return;
 191         }
 192         else
 193         {
 194             yaz_log(YLOG_DEBUG, "Connect OK");
 195             co->state = Conn_Open;
 196             if (cl)
 197                 client_set_state(cl, Client_Connected);
 198             iochan_settimeout(i, global_parameters.z3950_session_timeout);
 199         }
 200     }
 201
 202     else if (event & EVENT_INPUT)
 203     {
 204         int len = cs_get(co->link, &co->ibuf, &co->ibufsize);
 205
 206         if (len < 0)
 207         {
 208             yaz_log(YLOG_WARN|YLOG_ERRNO, "Error reading from %s",
 209                     client_get_url(cl));
 210             connection_destroy(co);
 211             return;
 212         }
 213         else if (len == 0)
 214         {
 215             yaz_log(YLOG_WARN, "EOF reading from %s", client_get_url(cl));
 216             connection_destroy(co);
 217             return;
 218         }
 219         else if (len > 1) // We discard input if we have no connection
 220         {
 221             co->state = Conn_Open;
 222
 223             if (client_is_our_response(cl))
 224             {
 225                 Z_APDU *a;
 226                 struct session_database *sdb = client_get_database(cl);
 227                 const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 228
 229                 odr_reset(global_parameters.odr_in);
 230                 odr_setbuf(global_parameters.odr_in, co->ibuf, len, 0);
 231                 if (!z_APDU(global_parameters.odr_in, &a, 0, 0))
 232                 {
 233                     client_fatal(cl);
 234                     return;
 235                 }
 236
 237                 if (apdulog && *apdulog && *apdulog != '0')
 238                 {
 239                     ODR p = odr_createmem(ODR_PRINT);
 240                     yaz_log(YLOG_LOG, "recv APDU %s", client_get_url(cl));
 241
 242                     odr_setprint(p, yaz_log_file());
 243                     z_APDU(p, &a, 0, 0);
 244                     odr_setprint(p, stderr);
 245                     odr_destroy(p);
 246                 }
 247                 switch (a->which)
 248                 {
 249                     case Z_APDU_initResponse:
 250                         client_init_response(cl, a);
 251                         break;
 252                     case Z_APDU_searchResponse:
 253                         client_search_response(cl, a);
 254                         break;
 255                     case Z_APDU_presentResponse:
 256                         client_present_response(cl, a);
 257                         break;
 258                     case Z_APDU_close:
 259                         client_close_response(cl, a);
 260                         break;
 261                     default:
 262                         yaz_log(YLOG_WARN,
 263                                 "Unexpected Z39.50 response from %s",
 264                                 client_get_url(cl));
 265                         client_fatal(cl);
 266                         return;
 267                 }
 268                 // We aren't expecting staggered output from target
 269                 // if (cs_more(t->link))
 270                 //    iochan_setevent(i, EVENT_INPUT);
 271             }
 272             else  // we throw away response and go to idle mode
 273             {
 274                 yaz_log(YLOG_DEBUG, "Ignoring result of expired operation");
 275                 client_set_state(cl, Client_Continue);
 276             }
 277         }
 278         /* if len==1 we do nothing but wait for more input */
 279     }
 280     client_continue(cl);
 281 }
 282
 283 // Disassociate connection from client
 284 void connection_release(struct connection *co)
 285 {
 286     struct client *cl = co->client;
 287
 288     yaz_log(YLOG_DEBUG, "Connection release %s", co->host->hostport);
 289     if (!cl)
 290         return;
 291     client_set_connection(cl, 0);
 292     co->client = 0;
 293 }
 294
 295 void connect_resolver_host(struct host *host)
 296 {
 297     struct connection *con = host->connections;
 298     while (con)
 299     {
 300         if (con->state == Conn_Resolving)
 301         {
 302             if (!host->ipport) /* unresolved */
 303             {
 304                 connection_destroy(con);
 305                 /* start all over .. at some point it will be NULL */
 306                 con = host->connections;
 307                 continue;
 308             }
 309             else if (!con->client)
 310             {
 311                 connection_destroy(con);
 312                 /* start all over .. at some point it will be NULL */
 313                 con = host->connections;
 314                 continue;
 315             }
 316             else
 317             {
 318                 connection_connect(con);
 319             }
 320         }
 321         else
 322         {
 323             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
 324         }
 325         con = con->next;
 326     }
 327 }
 328
 329 int connection_send_apdu(struct connection *co, Z_APDU *a)
 330 {
 331     char *buf;
 332     int len, r;
 333
 334     if (!z_APDU(global_parameters.odr_out, &a, 0, 0))
 335     {
 336         odr_perror(global_parameters.odr_out, "Encoding APDU");
 337         abort();
 338     }
 339     buf = odr_getbuf(global_parameters.odr_out, &len, 0);
 340     r = cs_put(co->link, buf, len);
 341     if (r < 0)
 342     {
 343         yaz_log(YLOG_WARN, "cs_put: %s", cs_errmsg(cs_errno(co->link)));
 344         return -1;
 345     }
 346     else if (r == 1)
 347     {
 348         fprintf(stderr, "cs_put incomplete (ParaZ does not handle that)\n");
 349         return -1;;
 350     }
 351     odr_reset(global_parameters.odr_out); /* release the APDU structure  */
 352     co->state = Conn_Waiting;
 353     iochan_setflags(co->iochan, EVENT_INPUT);
 354     return 0;
 355 }
 356
 357 struct host *connection_get_host(struct connection *con)
 358 {
 359     return con->host;
 360 }
 361
 362 int connection_connect(struct connection *con)
 363 {
 364     COMSTACK link = 0;
 365     struct host *host = connection_get_host(con);
 366     void *addr;
 367     int res;
 368
 369     struct session_database *sdb = client_get_database(con->client);
 370     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 371
 372     assert(host->ipport);
 373     assert(con);
 374
 375     if (!(link = cs_create(tcpip_type, 0, PROTO_Z3950)))
 376     {
 377         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create comstack");
 378         return -1;
 379     }
 380
 381     if (zproxy && *zproxy)
 382         con->zproxy = xstrdup(zproxy);
 383
 384     if (!con->zproxy)
 385     {
 386         /* no Z39.50 proxy needed - direct connect */
 387         yaz_log(YLOG_DEBUG, "Connection create %s", connection_get_url(con));
 388
 389         if (!(addr = cs_straddr(link, host->ipport)))
 390         {
 391             yaz_log(YLOG_WARN|YLOG_ERRNO,
 392                     "Lookup of IP address %s failed", host->ipport);
 393             return -1;
 394         }
 395
 396     } else {
 397         /* Z39.50 proxy connect */
 398         yaz_log(YLOG_DEBUG, "Connection create %s proxy %s",
 399                 connection_get_url(con), con->zproxy);
 400
 401         if (!(addr = cs_straddr(link, con->zproxy)))
 402         {
 403             yaz_log(YLOG_WARN|YLOG_ERRNO,
 404                     "Lookup of ZProxy IP address %s failed",
 405                     con->zproxy);
 406             return -1;
 407         }
 408     }
 409
 410     res = cs_connect(link, addr);
 411     if (res < 0)
 412     {
 413         yaz_log(YLOG_WARN|YLOG_ERRNO, "cs_connect %s",
 414                 connection_get_url(con));
 415         return -1;
 416     }
 417     con->link = link;
 418     con->state = Conn_Connecting;
 419     con->iochan = iochan_create(cs_fileno(link), connection_handler, 0);
 420     iochan_settimeout(con->iochan, global_parameters.z3950_connect_timeout);
 421     iochan_setdata(con->iochan, con);
 422     pazpar2_add_channel(con->iochan);
 423
 424     /* this fragment is bad DRY: from client_prep_connection */
 425     client_set_state(con->client, Client_Connecting);
 426     iochan_setflag(con->iochan, EVENT_OUTPUT);
 427     return 0;
 428 }
 429
 430 const char *connection_get_url(struct connection *co)
 431 {
 432     return client_get_url(co->client);
 433 }
 434
 435 void connection_set_authentication(struct connection *co, char *auth)
 436 {
 437     co->authentication = auth;
 438 }
 439
 440 // Ensure that client has a connection associated
 441 int client_prep_connection(struct client *cl)
 442 {
 443     struct connection *co;
 444     struct session *se = client_get_session(cl);
 445     struct host *host = client_get_host(cl);
 446     struct session_database *sdb = client_get_database(cl);
 447     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 448
 449     if (zproxy && zproxy[0] == '\0')
 450         zproxy = 0;
 451
 452     co = client_get_connection(cl);
 453
 454     yaz_log(YLOG_DEBUG, "Client prep %s", client_get_url(cl));
 455
 456     if (!co)
 457     {
 458         // See if someone else has an idle connection
 459         // We should look at timestamps here to select the longest-idle connection
 460         for (co = host->connections; co; co = co->next)
 461             if (co->state == Conn_Open &&
 462                 (!co->client || client_get_session(co->client) != se) &&
 463                 !strcmp(co->authentication,
 464                     session_setting_oneval(client_get_database(cl),
 465                     PZ_AUTHENTICATION)))
 466             {
 467                 if (zproxy == 0 && co->zproxy == 0)
 468                     break;
 469                 if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 470                     break;
 471             }
 472         if (co)
 473         {
 474             connection_release(co);
 475             client_set_connection(cl, co);
 476             co->client = cl;
 477         }
 478         else
 479             co = connection_create(cl);
 480     }
 481     if (co)
 482     {
 483         if (co->state == Conn_Connecting)
 484         {
 485             client_set_state(cl, Client_Connecting);
 486             iochan_setflag(co->iochan, EVENT_OUTPUT);
 487         }
 488         else if (co->state == Conn_Open)
 489         {
 490             if (client_get_state(cl) == Client_Error
 491                 || client_get_state(cl) == Client_Disconnected
 492                 || client_get_state(cl) == Client_Idle)
 493                 client_set_state(cl, Client_Continue);
 494             iochan_setflag(co->iochan, EVENT_OUTPUT);
 495         }
 496         return 1;
 497     }
 498     else
 499         return 0;
 500 }
 501
 502
 503
 504 /*
 505  * Local variables:
 506  * c-basic-offset: 4
 507  * indent-tabs-mode: nil
 508  * End:
 509  * vim: shiftwidth=4 tabstop=8 expandtab
 510  */