src/connection.c

   1 /* $Id: connection.c,v 1.9 2007-07-25 13:27:06 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     enum {
  64         Conn_Resolving,
  65         Conn_Connecting,
  66         Conn_Open,
  67         Conn_Waiting,
  68     } state;
  69     struct connection *next; // next for same host or next in free list
  70 };
  71
  72 static struct connection *connection_freelist = 0;
  73
  74 static void remove_connection_from_host(struct connection *con)
  75 {
  76     struct connection **conp = &con->host->connections;
  77     assert(con);
  78     while (*conp)
  79     {
  80         if (*conp == con)
  81         {
  82             *conp = (*conp)->next;
  83             return;
  84         }
  85         conp = &(*conp)->next;
  86     }
  87     assert(*conp == 0);
  88 }
  89
  90 // Close connection and recycle structure
  91 void connection_destroy(struct connection *co)
  92 {
  93     if (co->link)
  94     {
  95         cs_close(co->link);
  96         iochan_destroy(co->iochan);
  97     }
  98
  99     yaz_log(YLOG_DEBUG, "Connection destroy %s", co->host->hostport);
 100
 101     remove_connection_from_host(co);
 102     if (co->client)
 103     {
 104         client_disconnect(co->client);
 105     }
 106     co->next = connection_freelist;
 107     connection_freelist = co;
 108 }
 109
 110 // Creates a new connection for client, associated with the host of
 111 // client's database
 112 struct connection *connection_create(struct client *cl)
 113 {
 114     struct connection *new;
 115     struct host *host = client_get_host(cl);
 116
 117     if ((new = connection_freelist))
 118         connection_freelist = new->next;
 119     else
 120     {
 121         new = xmalloc(sizeof (struct connection));
 122         new->ibuf = 0;
 123         new->ibufsize = 0;
 124     }
 125     new->host = host;
 126     new->next = new->host->connections;
 127     new->host->connections = new;
 128     new->client = cl;
 129     new->authentication = "";
 130     client_set_connection(cl, new);
 131     new->link = 0;
 132     new->state = Conn_Resolving;
 133     if (host->ipport)
 134         connection_connect(new);
 135     return new;
 136 }
 137
 138 static void connection_handler(IOCHAN i, int event)
 139 {
 140     struct connection *co = iochan_getdata(i);
 141     struct client *cl = co->client;
 142     struct session *se = 0;
 143
 144     if (cl)
 145         se = client_get_session(cl);
 146     else
 147     {
 148         connection_destroy(co);
 149         return;
 150     }
 151
 152     if (event & EVENT_TIMEOUT)
 153     {
 154         if (co->state == Conn_Connecting)
 155         {
 156             yaz_log(YLOG_WARN,  "connect timeout %s", client_get_url(cl));
 157             client_fatal(cl);
 158         }
 159         else
 160         {
 161             yaz_log(YLOG_LOG,  "idle timeout %s", client_get_url(cl));
 162             connection_destroy(co);
 163         }
 164         return;
 165     }
 166     if (co->state == Conn_Connecting && event & EVENT_OUTPUT)
 167     {
 168         int errcode;
 169         socklen_t errlen = sizeof(errcode);
 170
 171         if (getsockopt(cs_fileno(co->link), SOL_SOCKET, SO_ERROR, &errcode,
 172             &errlen) < 0 || errcode != 0)
 173         {
 174             client_fatal(cl);
 175             return;
 176         }
 177         else
 178         {
 179             yaz_log(YLOG_DEBUG, "Connect OK");
 180             co->state = Conn_Open;
 181             if (cl)
 182                 client_set_state(cl, Client_Connected);
 183             iochan_settimeout(i, global_parameters.z3950_session_timeout);
 184         }
 185     }
 186
 187     else if (event & EVENT_INPUT)
 188     {
 189         int len = cs_get(co->link, &co->ibuf, &co->ibufsize);
 190
 191         if (len < 0)
 192         {
 193             yaz_log(YLOG_WARN|YLOG_ERRNO, "Error reading from %s",
 194                     client_get_url(cl));
 195             connection_destroy(co);
 196             return;
 197         }
 198         else if (len == 0)
 199         {
 200             yaz_log(YLOG_WARN, "EOF reading from %s", client_get_url(cl));
 201             connection_destroy(co);
 202             return;
 203         }
 204         else if (len > 1) // We discard input if we have no connection
 205         {
 206             co->state = Conn_Open;
 207
 208             if (client_is_our_response(cl))
 209             {
 210                 Z_APDU *a;
 211                 struct session_database *sdb = client_get_database(cl);
 212                 const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 213
 214                 odr_reset(global_parameters.odr_in);
 215                 odr_setbuf(global_parameters.odr_in, co->ibuf, len, 0);
 216                 if (!z_APDU(global_parameters.odr_in, &a, 0, 0))
 217                 {
 218                     client_fatal(cl);
 219                     return;
 220                 }
 221
 222                 if (apdulog && *apdulog && *apdulog != '0')
 223                 {
 224                     ODR p = odr_createmem(ODR_PRINT);
 225                     yaz_log(YLOG_LOG, "recv APDU %s", client_get_url(cl));
 226
 227                     odr_setprint(p, yaz_log_file());
 228                     z_APDU(p, &a, 0, 0);
 229                     odr_setprint(p, stderr);
 230                     odr_destroy(p);
 231                 }
 232                 switch (a->which)
 233                 {
 234                     case Z_APDU_initResponse:
 235                         client_init_response(cl, a);
 236                         break;
 237                     case Z_APDU_searchResponse:
 238                         client_search_response(cl, a);
 239                         break;
 240                     case Z_APDU_presentResponse:
 241                         client_present_response(cl, a);
 242                         break;
 243                     case Z_APDU_close:
 244                         client_close_response(cl, a);
 245                         break;
 246                     default:
 247                         yaz_log(YLOG_WARN,
 248                                 "Unexpected Z39.50 response from %s",
 249                                 client_get_url(cl));
 250                         client_fatal(cl);
 251                         return;
 252                 }
 253                 // We aren't expecting staggered output from target
 254                 // if (cs_more(t->link))
 255                 //    iochan_setevent(i, EVENT_INPUT);
 256             }
 257             else  // we throw away response and go to idle mode
 258             {
 259                 yaz_log(YLOG_DEBUG, "Ignoring result of expired operation");
 260                 client_set_state(cl, Client_Idle);
 261             }
 262         }
 263         /* if len==1 we do nothing but wait for more input */
 264     }
 265     client_continue(cl);
 266 }
 267
 268 // Disassociate connection from client
 269 void connection_release(struct connection *co)
 270 {
 271     struct client *cl = co->client;
 272
 273     yaz_log(YLOG_DEBUG, "Connection release %s", co->host->hostport);
 274     if (!cl)
 275         return;
 276     client_set_connection(cl, 0);
 277     co->client = 0;
 278 }
 279
 280 void connect_resolver_host(struct host *host)
 281 {
 282     struct connection *con = host->connections;
 283     while (con)
 284     {
 285         if (con->state == Conn_Resolving)
 286         {
 287             if (!host->ipport) /* unresolved */
 288             {
 289                 connection_destroy(con);
 290                 /* start all over .. at some point it will be NULL */
 291                 con = host->connections;
 292                 continue;
 293             }
 294             else if (!con->client)
 295             {
 296                 connection_destroy(con);
 297                 /* start all over .. at some point it will be NULL */
 298                 con = host->connections;
 299                 continue;
 300             }
 301             else
 302             {
 303                 connection_connect(con);
 304             }
 305         }
 306         else
 307         {
 308             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
 309         }
 310         con = con->next;
 311     }
 312 }
 313
 314 int connection_send_apdu(struct connection *co, Z_APDU *a)
 315 {
 316     char *buf;
 317     int len, r;
 318
 319     if (!z_APDU(global_parameters.odr_out, &a, 0, 0))
 320     {
 321         odr_perror(global_parameters.odr_out, "Encoding APDU");
 322         abort();
 323     }
 324     buf = odr_getbuf(global_parameters.odr_out, &len, 0);
 325     r = cs_put(co->link, buf, len);
 326     if (r < 0)
 327     {
 328         yaz_log(YLOG_WARN, "cs_put: %s", cs_errmsg(cs_errno(co->link)));
 329         return -1;
 330     }
 331     else if (r == 1)
 332     {
 333         fprintf(stderr, "cs_put incomplete (ParaZ does not handle that)\n");
 334         exit(1);
 335     }
 336     odr_reset(global_parameters.odr_out); /* release the APDU structure  */
 337     co->state = Conn_Waiting;
 338     iochan_setflags(co->iochan, EVENT_INPUT);
 339     return 0;
 340 }
 341
 342 struct host *connection_get_host(struct connection *con)
 343 {
 344     return con->host;
 345 }
 346
 347 int connection_connect(struct connection *con)
 348 {
 349     COMSTACK link = 0;
 350     struct host *host = connection_get_host(con);
 351     void *addr;
 352     int res;
 353
 354     struct session_database *sdb = client_get_database(con->client);
 355     char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 356
 357     assert(host->ipport);
 358     assert(con);
 359
 360     if (!(link = cs_create(tcpip_type, 0, PROTO_Z3950)))
 361     {
 362         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create comstack");
 363         return -1;
 364     }
 365
 366     if (!zproxy || 0 == strlen(zproxy)){
 367         /* no Z39.50 proxy needed - direct connect */
 368         yaz_log(YLOG_DEBUG, "Connection create %s", connection_get_url(con));
 369
 370         if (!(addr = cs_straddr(link, host->ipport)))
 371         {
 372             yaz_log(YLOG_WARN|YLOG_ERRNO,
 373                     "Lookup of IP address %s failed", host->ipport);
 374             return -1;
 375         }
 376
 377     } else {
 378         /* Z39.50 proxy connect */
 379         yaz_log(YLOG_DEBUG, "Connection create %s proxy %s",
 380                 connection_get_url(con), zproxy);
 381
 382         if (!(addr = cs_straddr(link, zproxy)))
 383         {
 384             yaz_log(YLOG_WARN|YLOG_ERRNO,
 385                     "Lookup of ZProxy IP address %s failed",
 386                     zproxy);
 387             return -1;
 388         }
 389     }
 390
 391     res = cs_connect(link, addr);
 392     if (res < 0)
 393     {
 394         yaz_log(YLOG_WARN|YLOG_ERRNO, "cs_connect %s",
 395                 connection_get_url(con));
 396         return -1;
 397     }
 398     con->link = link;
 399     con->state = Conn_Connecting;
 400     con->iochan = iochan_create(cs_fileno(link), connection_handler, 0);
 401     iochan_settimeout(con->iochan, global_parameters.z3950_connect_timeout);
 402     iochan_setdata(con->iochan, con);
 403     pazpar2_add_channel(con->iochan);
 404
 405     /* this fragment is bad DRY: from client_prep_connection */
 406     client_set_state(con->client, Client_Connecting);
 407     iochan_setflag(con->iochan, EVENT_OUTPUT);
 408     return 0;
 409 }
 410
 411 const char *connection_get_url(struct connection *co)
 412 {
 413     return client_get_url(co->client);
 414 }
 415
 416 void connection_set_authentication(struct connection *co, char *auth)
 417 {
 418     co->authentication = auth;
 419 }
 420
 421 // Ensure that client has a connection associated
 422 int client_prep_connection(struct client *cl)
 423 {
 424     struct connection *co;
 425     struct session *se = client_get_session(cl);
 426     struct host *host = client_get_host(cl);
 427
 428     co = client_get_connection(cl);
 429
 430     yaz_log(YLOG_DEBUG, "Client prep %s", client_get_url(cl));
 431
 432     if (!co)
 433     {
 434         // See if someone else has an idle connection
 435         // We should look at timestamps here to select the longest-idle connection
 436         for (co = host->connections; co; co = co->next)
 437             if (co->state == Conn_Open &&
 438                 (!co->client || client_get_session(co->client) != se) &&
 439                 !strcmp(co->authentication,
 440                     session_setting_oneval(client_get_database(cl),
 441                     PZ_AUTHENTICATION)))
 442                 break;
 443         if (co)
 444         {
 445             connection_release(co);
 446             client_set_connection(cl, co);
 447             co->client = cl;
 448         }
 449         else
 450             co = connection_create(cl);
 451     }
 452     if (co)
 453     {
 454         if (co->state == Conn_Connecting)
 455         {
 456             client_set_state(cl, Client_Connecting);
 457             iochan_setflag(co->iochan, EVENT_OUTPUT);
 458         }
 459         else if (co->state == Conn_Open)
 460         {
 461             if (client_get_state(cl) == Client_Error
 462                 || client_get_state(cl) == Client_Disconnected)
 463                 client_set_state(cl, Client_Idle);
 464             iochan_setflag(co->iochan, EVENT_OUTPUT);
 465         }
 466         return 1;
 467     }
 468     else
 469         return 0;
 470 }
 471
 472
 473
 474 /*
 475  * Local variables:
 476  * c-basic-offset: 4
 477  * indent-tabs-mode: nil
 478  * End:
 479  * vim: shiftwidth=4 tabstop=8 expandtab
 480  */