src/connection.c

   1 /* $Id: connection.c,v 1.12 2007-09-20 08:13:27 adam Exp $
   2    Copyright (c) 2006-2007, Index Data.
   3
   4 This file is part of Pazpar2.
   5
   6 Pazpar2 is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 2, or (at your option) any later
   9 version.
  10
  11 Pazpar2 is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with Pazpar2; see the file LICENSE.  If not, write to the
  18 Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  19 02111-1307, USA.
  20  */
  21
  22 /** \file connection.c
  23     \brief Z39.50 connection (low-level client)
  24 */
  25
  26 #include <stdlib.h>
  27 #include <stdio.h>
  28 #include <string.h>
  29 #include <sys/time.h>
  30 #include <unistd.h>
  31 #include <sys/socket.h>
  32 #include <netdb.h>
  33 #include <signal.h>
  34 #include <ctype.h>
  35 #include <assert.h>
  36
  37 #if HAVE_CONFIG_H
  38 #include "cconfig.h"
  39 #endif
  40
  41 #include <yaz/log.h>
  42 #include <yaz/comstack.h>
  43 #include <yaz/tcpip.h>
  44 #include "connection.h"
  45 #include "eventl.h"
  46 #include "pazpar2.h"
  47 #include "host.h"
  48 #include "client.h"
  49 #include "settings.h"
  50 #include "parameters.h"
  51
  52
  53 /** \brief Represents a physical, reusable  connection to a remote Z39.50 host
  54  */
  55 struct connection {
  56     IOCHAN iochan;
  57     COMSTACK link;
  58     struct host *host;
  59     struct client *client;
  60     char *ibuf;
  61     int ibufsize;
  62     char *authentication; // Empty string or authentication string if set
  63     char *zproxy;
  64     enum {
  65         Conn_Resolving,
  66         Conn_Connecting,
  67         Conn_Open,
  68         Conn_Waiting,
  69     } state;
  70     struct connection *next; // next for same host or next in free list
  71 };
  72
  73 static struct connection *connection_freelist = 0;
  74
  75 static void remove_connection_from_host(struct connection *con)
  76 {
  77     struct connection **conp = &con->host->connections;
  78     assert(con);
  79     while (*conp)
  80     {
  81         if (*conp == con)
  82         {
  83             *conp = (*conp)->next;
  84             return;
  85         }
  86         conp = &(*conp)->next;
  87     }
  88     assert(*conp == 0);
  89 }
  90
  91 // Close connection and recycle structure
  92 void connection_destroy(struct connection *co)
  93 {
  94     if (co->link)
  95     {
  96         cs_close(co->link);
  97         iochan_destroy(co->iochan);
  98     }
  99
 100     yaz_log(YLOG_DEBUG, "Connection destroy %s", co->host->hostport);
 101
 102     remove_connection_from_host(co);
 103     if (co->client)
 104     {
 105         client_disconnect(co->client);
 106     }
 107     xfree(co->zproxy);
 108     co->zproxy = 0;
 109     co->next = connection_freelist;
 110     connection_freelist = co;
 111 }
 112
 113 // Creates a new connection for client, associated with the host of
 114 // client's database
 115 struct connection *connection_create(struct client *cl)
 116 {
 117     struct connection *new;
 118     struct host *host = client_get_host(cl);
 119
 120     if ((new = connection_freelist))
 121         connection_freelist = new->next;
 122     else
 123     {
 124         new = xmalloc(sizeof (struct connection));
 125         new->ibuf = 0;
 126         new->ibufsize = 0;
 127     }
 128     new->host = host;
 129     new->next = new->host->connections;
 130     new->host->connections = new;
 131     new->client = cl;
 132     new->authentication = "";
 133     new->zproxy = 0;
 134     client_set_connection(cl, new);
 135     new->link = 0;
 136     new->state = Conn_Resolving;
 137     if (host->ipport)
 138         connection_connect(new);
 139     return new;
 140 }
 141
 142 static void connection_handler(IOCHAN i, int event)
 143 {
 144     struct connection *co = iochan_getdata(i);
 145     struct client *cl = co->client;
 146     struct session *se = 0;
 147
 148     if (cl)
 149         se = client_get_session(cl);
 150     else
 151     {
 152         connection_destroy(co);
 153         return;
 154     }
 155
 156     if (event & EVENT_TIMEOUT)
 157     {
 158         if (co->state == Conn_Connecting)
 159         {
 160             yaz_log(YLOG_WARN,  "connect timeout %s", client_get_url(cl));
 161             client_fatal(cl);
 162         }
 163         else
 164         {
 165             yaz_log(YLOG_LOG,  "idle timeout %s", client_get_url(cl));
 166             connection_destroy(co);
 167         }
 168         return;
 169     }
 170     if (co->state == Conn_Connecting && event & EVENT_OUTPUT)
 171     {
 172         int errcode;
 173         socklen_t errlen = sizeof(errcode);
 174
 175         if (getsockopt(cs_fileno(co->link), SOL_SOCKET, SO_ERROR, &errcode,
 176             &errlen) < 0 || errcode != 0)
 177         {
 178             client_fatal(cl);
 179             return;
 180         }
 181         else
 182         {
 183             yaz_log(YLOG_DEBUG, "Connect OK");
 184             co->state = Conn_Open;
 185             if (cl)
 186                 client_set_state(cl, Client_Connected);
 187             iochan_settimeout(i, global_parameters.z3950_session_timeout);
 188         }
 189     }
 190
 191     else if (event & EVENT_INPUT)
 192     {
 193         int len = cs_get(co->link, &co->ibuf, &co->ibufsize);
 194
 195         if (len < 0)
 196         {
 197             yaz_log(YLOG_WARN|YLOG_ERRNO, "Error reading from %s",
 198                     client_get_url(cl));
 199             connection_destroy(co);
 200             return;
 201         }
 202         else if (len == 0)
 203         {
 204             yaz_log(YLOG_WARN, "EOF reading from %s", client_get_url(cl));
 205             connection_destroy(co);
 206             return;
 207         }
 208         else if (len > 1) // We discard input if we have no connection
 209         {
 210             co->state = Conn_Open;
 211
 212             if (client_is_our_response(cl))
 213             {
 214                 Z_APDU *a;
 215                 struct session_database *sdb = client_get_database(cl);
 216                 const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 217
 218                 odr_reset(global_parameters.odr_in);
 219                 odr_setbuf(global_parameters.odr_in, co->ibuf, len, 0);
 220                 if (!z_APDU(global_parameters.odr_in, &a, 0, 0))
 221                 {
 222                     client_fatal(cl);
 223                     return;
 224                 }
 225
 226                 if (apdulog && *apdulog && *apdulog != '0')
 227                 {
 228                     ODR p = odr_createmem(ODR_PRINT);
 229                     yaz_log(YLOG_LOG, "recv APDU %s", client_get_url(cl));
 230
 231                     odr_setprint(p, yaz_log_file());
 232                     z_APDU(p, &a, 0, 0);
 233                     odr_setprint(p, stderr);
 234                     odr_destroy(p);
 235                 }
 236                 switch (a->which)
 237                 {
 238                     case Z_APDU_initResponse:
 239                         client_init_response(cl, a);
 240                         break;
 241                     case Z_APDU_searchResponse:
 242                         client_search_response(cl, a);
 243                         break;
 244                     case Z_APDU_presentResponse:
 245                         client_present_response(cl, a);
 246                         break;
 247                     case Z_APDU_close:
 248                         client_close_response(cl, a);
 249                         break;
 250                     default:
 251                         yaz_log(YLOG_WARN,
 252                                 "Unexpected Z39.50 response from %s",
 253                                 client_get_url(cl));
 254                         client_fatal(cl);
 255                         return;
 256                 }
 257                 // We aren't expecting staggered output from target
 258                 // if (cs_more(t->link))
 259                 //    iochan_setevent(i, EVENT_INPUT);
 260             }
 261             else  // we throw away response and go to idle mode
 262             {
 263                 yaz_log(YLOG_DEBUG, "Ignoring result of expired operation");
 264                 client_set_state(cl, Client_Continue);
 265             }
 266         }
 267         /* if len==1 we do nothing but wait for more input */
 268     }
 269     client_continue(cl);
 270 }
 271
 272 // Disassociate connection from client
 273 void connection_release(struct connection *co)
 274 {
 275     struct client *cl = co->client;
 276
 277     yaz_log(YLOG_DEBUG, "Connection release %s", co->host->hostport);
 278     if (!cl)
 279         return;
 280     client_set_connection(cl, 0);
 281     co->client = 0;
 282 }
 283
 284 void connect_resolver_host(struct host *host)
 285 {
 286     struct connection *con = host->connections;
 287     while (con)
 288     {
 289         if (con->state == Conn_Resolving)
 290         {
 291             if (!host->ipport) /* unresolved */
 292             {
 293                 connection_destroy(con);
 294                 /* start all over .. at some point it will be NULL */
 295                 con = host->connections;
 296                 continue;
 297             }
 298             else if (!con->client)
 299             {
 300                 connection_destroy(con);
 301                 /* start all over .. at some point it will be NULL */
 302                 con = host->connections;
 303                 continue;
 304             }
 305             else
 306             {
 307                 connection_connect(con);
 308             }
 309         }
 310         else
 311         {
 312             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
 313         }
 314         con = con->next;
 315     }
 316 }
 317
 318 int connection_send_apdu(struct connection *co, Z_APDU *a)
 319 {
 320     char *buf;
 321     int len, r;
 322
 323     if (!z_APDU(global_parameters.odr_out, &a, 0, 0))
 324     {
 325         odr_perror(global_parameters.odr_out, "Encoding APDU");
 326         abort();
 327     }
 328     buf = odr_getbuf(global_parameters.odr_out, &len, 0);
 329     r = cs_put(co->link, buf, len);
 330     if (r < 0)
 331     {
 332         yaz_log(YLOG_WARN, "cs_put: %s", cs_errmsg(cs_errno(co->link)));
 333         return -1;
 334     }
 335     else if (r == 1)
 336     {
 337         fprintf(stderr, "cs_put incomplete (ParaZ does not handle that)\n");
 338         return -1;;
 339     }
 340     odr_reset(global_parameters.odr_out); /* release the APDU structure  */
 341     co->state = Conn_Waiting;
 342     iochan_setflags(co->iochan, EVENT_INPUT);
 343     return 0;
 344 }
 345
 346 struct host *connection_get_host(struct connection *con)
 347 {
 348     return con->host;
 349 }
 350
 351 int connection_connect(struct connection *con)
 352 {
 353     COMSTACK link = 0;
 354     struct host *host = connection_get_host(con);
 355     void *addr;
 356     int res;
 357
 358     struct session_database *sdb = client_get_database(con->client);
 359     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 360
 361     assert(host->ipport);
 362     assert(con);
 363
 364     if (!(link = cs_create(tcpip_type, 0, PROTO_Z3950)))
 365     {
 366         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create comstack");
 367         return -1;
 368     }
 369
 370     if (zproxy && *zproxy)
 371         con->zproxy = xstrdup(zproxy);
 372
 373     if (!con->zproxy)
 374     {
 375         /* no Z39.50 proxy needed - direct connect */
 376         yaz_log(YLOG_DEBUG, "Connection create %s", connection_get_url(con));
 377
 378         if (!(addr = cs_straddr(link, host->ipport)))
 379         {
 380             yaz_log(YLOG_WARN|YLOG_ERRNO,
 381                     "Lookup of IP address %s failed", host->ipport);
 382             return -1;
 383         }
 384
 385     } else {
 386         /* Z39.50 proxy connect */
 387         yaz_log(YLOG_DEBUG, "Connection create %s proxy %s",
 388                 connection_get_url(con), con->zproxy);
 389
 390         if (!(addr = cs_straddr(link, con->zproxy)))
 391         {
 392             yaz_log(YLOG_WARN|YLOG_ERRNO,
 393                     "Lookup of ZProxy IP address %s failed",
 394                     con->zproxy);
 395             return -1;
 396         }
 397     }
 398
 399     res = cs_connect(link, addr);
 400     if (res < 0)
 401     {
 402         yaz_log(YLOG_WARN|YLOG_ERRNO, "cs_connect %s",
 403                 connection_get_url(con));
 404         return -1;
 405     }
 406     con->link = link;
 407     con->state = Conn_Connecting;
 408     con->iochan = iochan_create(cs_fileno(link), connection_handler, 0);
 409     iochan_settimeout(con->iochan, global_parameters.z3950_connect_timeout);
 410     iochan_setdata(con->iochan, con);
 411     pazpar2_add_channel(con->iochan);
 412
 413     /* this fragment is bad DRY: from client_prep_connection */
 414     client_set_state(con->client, Client_Connecting);
 415     iochan_setflag(con->iochan, EVENT_OUTPUT);
 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 void connection_set_authentication(struct connection *co, char *auth)
 425 {
 426     co->authentication = auth;
 427 }
 428
 429 // Ensure that client has a connection associated
 430 int client_prep_connection(struct client *cl)
 431 {
 432     struct connection *co;
 433     struct session *se = client_get_session(cl);
 434     struct host *host = client_get_host(cl);
 435     struct session_database *sdb = client_get_database(cl);
 436     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 437
 438     if (zproxy && zproxy[0] == '\0')
 439         zproxy = 0;
 440
 441     co = client_get_connection(cl);
 442
 443     yaz_log(YLOG_DEBUG, "Client prep %s", client_get_url(cl));
 444
 445     if (!co)
 446     {
 447         // See if someone else has an idle connection
 448         // We should look at timestamps here to select the longest-idle connection
 449         for (co = host->connections; co; co = co->next)
 450             if (co->state == Conn_Open &&
 451                 (!co->client || client_get_session(co->client) != se) &&
 452                 !strcmp(co->authentication,
 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         }
 467         else
 468             co = connection_create(cl);
 469     }
 470     if (co)
 471     {
 472         if (co->state == Conn_Connecting)
 473         {
 474             client_set_state(cl, Client_Connecting);
 475             iochan_setflag(co->iochan, EVENT_OUTPUT);
 476         }
 477         else if (co->state == Conn_Open)
 478         {
 479             if (client_get_state(cl) == Client_Error
 480                 || client_get_state(cl) == Client_Disconnected
 481                 || client_get_state(cl) == Client_Idle)
 482                 client_set_state(cl, Client_Continue);
 483             iochan_setflag(co->iochan, EVENT_OUTPUT);
 484         }
 485         return 1;
 486     }
 487     else
 488         return 0;
 489 }
 490
 491
 492
 493 /*
 494  * Local variables:
 495  * c-basic-offset: 4
 496  * indent-tabs-mode: nil
 497  * End:
 498  * vim: shiftwidth=4 tabstop=8 expandtab
 499  */