src/util/connection.c

   1 /*
   2      This file is part of GNUnet.
   3      (C) 2009 Christian Grothoff (and other contributing authors)
   4
   5      GNUnet is free software; you can redistribute it and/or modify
   6      it under the terms of the GNU General Public License as published
   7      by the Free Software Foundation; either version 2, or (at your
   8      option) any later version.
   9
  10      GNUnet is distributed in the hope that it will be useful, but
  11      WITHOUT ANY WARRANTY; without even the implied warranty of
  12      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13      General Public License for more details.
  14
  15      You should have received a copy of the GNU General Public License
  16      along with GNUnet; see the file COPYING.  If not, write to the
  17      Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18      Boston, MA 02111-1307, USA.
  19 */
  20
  21 /**
  22  * @file util/connection.c
  23  * @brief  TCP connection management
  24  * @author Christian Grothoff
  25  *
  26  * This code is rather complex.  Only modify it if you
  27  * 1) Have a NEW testcase showing that the new code
  28  *    is needed and correct
  29  * 2) All EXISTING testcases pass with the new code
  30  * These rules should apply in general, but for this
  31  * module they are VERY, VERY important.
  32  */
  33
  34 #include "platform.h"
  35 #include "gnunet_common.h"
  36 #include "gnunet_connection_lib.h"
  37 #include "gnunet_container_lib.h"
  38 #include "gnunet_resolver_service.h"
  39 #include "gnunet_scheduler_lib.h"
  40 #include "gnunet_server_lib.h"
  41
  42 #define DEBUG_CONNECTION GNUNET_NO
  43
  44
  45 /**
  46  * Possible functions to call after connect failed or succeeded.
  47  */
  48 enum ConnectContinuations
  49 {
  50     /**
  51      * Call nothing.
  52      */
  53   COCO_NONE = 0,
  54
  55     /**
  56      * Call "receive_again".
  57      */
  58   COCO_RECEIVE_AGAIN = 1,
  59
  60     /**
  61      * Call "transmit_ready".
  62      */
  63   COCO_TRANSMIT_READY = 2,
  64
  65     /**
  66      * Call "destroy_continuation".
  67      */
  68   COCO_DESTROY_CONTINUATION = 4
  69 };
  70
  71
  72 /**
  73  * Transmission handle.  There can only be one for each connection.
  74  */
  75 struct GNUNET_CONNECTION_TransmitHandle
  76 {
  77
  78   /**
  79    * Function to call if the send buffer has notify_size
  80    * bytes available.
  81    */
  82   GNUNET_CONNECTION_TransmitReadyNotify notify_ready;
  83
  84   /**
  85    * Closure for notify_ready.
  86    */
  87   void *notify_ready_cls;
  88
  89   /**
  90    * Our socket handle.
  91    */
  92   struct GNUNET_CONNECTION_Handle *sh;
  93
  94   /**
  95    * Timeout for receiving (in absolute time).
  96    */
  97   struct GNUNET_TIME_Absolute transmit_timeout;
  98
  99   /**
 100    * Task called on timeout.
 101    */
 102   GNUNET_SCHEDULER_TaskIdentifier timeout_task;
 103
 104   /**
 105    * At what number of bytes available in the
 106    * write buffer should the notify method be called?
 107    */
 108   size_t notify_size;
 109
 110 };
 111
 112
 113 /**
 114  * During connect, we try multiple possible IP addresses
 115  * to find out which one might work.
 116  */
 117 struct AddressProbe
 118 {
 119
 120   /**
 121    * This is a linked list.
 122    */
 123   struct AddressProbe *next;
 124
 125   /**
 126    * This is a doubly-linked list.
 127    */
 128   struct AddressProbe *prev;
 129
 130   /**
 131    * The address; do not free (allocated at the end of this struct).
 132    */
 133   const struct sockaddr *addr;
 134
 135   /**
 136    * Underlying OS's socket.
 137    */
 138   struct GNUNET_NETWORK_Handle *sock;
 139
 140   /**
 141    * Connection for which we are probing.
 142    */
 143   struct GNUNET_CONNECTION_Handle *h;
 144
 145   /**
 146    * Lenth of addr.
 147    */
 148   socklen_t addrlen;
 149
 150   /**
 151    * Task waiting for the socket to finish connecting.
 152    */
 153   GNUNET_SCHEDULER_TaskIdentifier task;
 154 };
 155
 156
 157 /**
 158  * @brief handle for a network socket
 159  */
 160 struct GNUNET_CONNECTION_Handle
 161 {
 162
 163   /**
 164    * Scheduler that was used for the connect task.
 165    */
 166   struct GNUNET_SCHEDULER_Handle *sched;
 167
 168   /**
 169    * Configuration to use.
 170    */
 171   const struct GNUNET_CONFIGURATION_Handle *cfg;
 172
 173   /**
 174    * Linked list of sockets we are currently trying out
 175    * (during connect).
 176    */
 177   struct AddressProbe *ap_head;
 178
 179   /**
 180    * Linked list of sockets we are currently trying out
 181    * (during connect).
 182    */
 183   struct AddressProbe *ap_tail;
 184
 185   /**
 186    * Network address of the other end-point, may be NULL.
 187    */
 188   struct sockaddr *addr;
 189
 190   /**
 191    * Pointer to the hostname if socket was
 192    * created using DNS lookup, otherwise NULL.
 193    */
 194   char *hostname;
 195
 196   /**
 197    * Underlying OS's socket, set to NULL after fatal errors.
 198    */
 199   struct GNUNET_NETWORK_Handle *sock;
 200
 201   /**
 202    * Function to call on data received, NULL if no receive is pending.
 203    */
 204   GNUNET_CONNECTION_Receiver receiver;
 205
 206   /**
 207    * Closure for receiver.
 208    */
 209   void *receiver_cls;
 210
 211   /**
 212    * Pointer to our write buffer.
 213    */
 214   char *write_buffer;
 215
 216   /**
 217    * Current size of our write buffer.
 218    */
 219   size_t write_buffer_size;
 220
 221   /**
 222    * Current write-offset in write buffer (where
 223    * would we write next).
 224    */
 225   size_t write_buffer_off;
 226
 227   /**
 228    * Current read-offset in write buffer (how many
 229    * bytes have already been sent).
 230    */
 231   size_t write_buffer_pos;
 232
 233   /**
 234    * Length of addr.
 235    */
 236   socklen_t addrlen;
 237
 238   /**
 239    * Read task that we may need to wait for.
 240    */
 241   GNUNET_SCHEDULER_TaskIdentifier read_task;
 242
 243   /**
 244    * Write task that we may need to wait for.
 245    */
 246   GNUNET_SCHEDULER_TaskIdentifier write_task;
 247
 248   /**
 249    * Destroy task (if already scheduled).
 250    */
 251   GNUNET_SCHEDULER_TaskIdentifier destroy_task;
 252
 253   /**
 254    * Handle to a pending DNS lookup request.
 255    */
 256   struct GNUNET_RESOLVER_RequestHandle *dns_active;
 257
 258   /**
 259    * The handle we return for GNUNET_CONNECTION_notify_transmit_ready.
 260    */
 261   struct GNUNET_CONNECTION_TransmitHandle nth;
 262
 263   /**
 264    * Timeout for receiving (in absolute time).
 265    */
 266   struct GNUNET_TIME_Absolute receive_timeout;
 267
 268   /**
 269    * Functions to call after connect failed or succeeded.
 270    */
 271   enum ConnectContinuations ccs;
 272
 273   /**
 274    * Maximum number of bytes to read (for receiving).
 275    */
 276   size_t max;
 277
 278   /**
 279    * Ignore GNUNET_SCHEDULER_REASON_SHUTDOWN for this socket.
 280    */
 281   int ignore_shutdown;
 282
 283   /**
 284    * Port to connect to.
 285    */
 286   uint16_t port;
 287
 288   /**
 289    * When shutdown, do not ever actually close the socket, but
 290    * free resources.  Only should ever be set if using program
 291    * termination as a signal (because only then will the leaked
 292    * socket be freed!)
 293    */
 294   int16_t persist;
 295
 296 };
 297
 298 /**
 299  * Set the persist option on this connection handle.  Indicates
 300  * that the underlying socket or fd should never really be closed.
 301  * Used for indicating process death.
 302  *
 303  * @param sock the connection to set persistent
 304  */
 305 void GNUNET_CONNECTION_persist_(struct GNUNET_CONNECTION_Handle *sock)
 306 {
 307   sock->persist = GNUNET_YES;
 308 }
 309
 310 /**
 311  * Create a socket handle by boxing an existing OS socket.  The OS
 312  * socket should henceforth be no longer used directly.
 313  * GNUNET_socket_destroy will close it.
 314  *
 315  * @param sched scheduler to use
 316  * @param osSocket existing socket to box
 317  * @return the boxed socket handle
 318  */
 319 struct GNUNET_CONNECTION_Handle *
 320 GNUNET_CONNECTION_create_from_existing (struct GNUNET_SCHEDULER_Handle
 321                                         *sched,
 322                                         struct GNUNET_NETWORK_Handle
 323                                         *osSocket)
 324 {
 325   struct GNUNET_CONNECTION_Handle *ret;
 326   ret = GNUNET_malloc (sizeof (struct GNUNET_CONNECTION_Handle));
 327   ret->write_buffer_size = GNUNET_SERVER_MIN_BUFFER_SIZE;
 328   ret->write_buffer = GNUNET_malloc(ret->write_buffer_size);
 329   ret->sock = osSocket;
 330   ret->sched = sched;
 331   return ret;
 332 }
 333
 334
 335 /**
 336  * Create a socket handle by accepting on a listen socket.  This
 337  * function may block if the listen socket has no connection ready.
 338  *
 339  * @param sched scheduler to use
 340  * @param access function to use to check if access is allowed
 341  * @param access_cls closure for access
 342  * @param lsock listen socket
 343  * @return the socket handle, NULL on error
 344  */
 345 struct GNUNET_CONNECTION_Handle *
 346 GNUNET_CONNECTION_create_from_accept (struct GNUNET_SCHEDULER_Handle
 347                                       *sched,
 348                                       GNUNET_CONNECTION_AccessCheck access,
 349                                       void *access_cls,
 350                                       struct GNUNET_NETWORK_Handle *lsock)
 351 {
 352   struct GNUNET_CONNECTION_Handle *ret;
 353   char addr[128];
 354   socklen_t addrlen;
 355   struct GNUNET_NETWORK_Handle *sock;
 356   int aret;
 357   struct sockaddr_in *v4;
 358   struct sockaddr_in6 *v6;
 359   struct sockaddr *sa;
 360   void *uaddr;
 361
 362   addrlen = sizeof (addr);
 363   sock =
 364     GNUNET_NETWORK_socket_accept (lsock, (struct sockaddr *) &addr, &addrlen);
 365   if (NULL == sock)
 366     {
 367       GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "accept");
 368       return NULL;
 369     }
 370   if ( (addrlen > sizeof (addr)) ||
 371        (addrlen < sizeof (sa_family_t)) )
 372     {
 373       GNUNET_break (0);
 374       GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (sock));
 375       return NULL;
 376     }
 377
 378   sa = (struct sockaddr *) addr;
 379   v6 = (struct sockaddr_in6 *) addr;
 380   if ((sa->sa_family == AF_INET6) && (IN6_IS_ADDR_V4MAPPED (&v6->sin6_addr)))
 381     {
 382       /* convert to V4 address */
 383       v4 = GNUNET_malloc (sizeof (struct sockaddr_in));
 384       memset (v4, 0, sizeof (struct sockaddr_in));
 385       v4->sin_family = AF_INET;
 386       memcpy (&v4->sin_addr,
 387               &((char *) &v6->sin6_addr)[sizeof (struct in6_addr) -
 388                                          sizeof (struct in_addr)],
 389               sizeof (struct in_addr));
 390       v4->sin_port = v6->sin6_port;
 391       uaddr = v4;
 392       addrlen = sizeof (struct sockaddr_in);
 393     }
 394   else
 395     {
 396       uaddr = GNUNET_malloc (addrlen);
 397       memcpy (uaddr, addr, addrlen);
 398     }
 399
 400   if ((access != NULL) &&
 401       (GNUNET_YES != (aret = access (access_cls, uaddr, addrlen))))
 402     {
 403       if (aret == GNUNET_NO)
 404         GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 405                     _("Access denied to `%s'\n"),
 406                     GNUNET_a2s (uaddr, addrlen));
 407       GNUNET_break (GNUNET_OK ==
 408                     GNUNET_NETWORK_socket_shutdown (sock, SHUT_RDWR));
 409       GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (sock));
 410       GNUNET_free (uaddr);
 411       return NULL;
 412     }
 413   ret = GNUNET_malloc (sizeof (struct GNUNET_CONNECTION_Handle));
 414   ret->write_buffer_size = GNUNET_SERVER_MIN_BUFFER_SIZE;
 415   ret->write_buffer = GNUNET_malloc(ret->write_buffer_size);
 416   ret->addr = uaddr;
 417   ret->addrlen = addrlen;
 418   ret->sock = sock;
 419   ret->sched = sched;
 420 #if DEBUG_CONNECTION
 421   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 422               _("Accepting connection from `%s': %p\n"),
 423               GNUNET_a2s (uaddr, addrlen), ret);
 424 #endif
 425   return ret;
 426 }
 427
 428 /**
 429  * Obtain the network address of the other party.
 430  *
 431  * @param sock the client to get the address for
 432  * @param addr where to store the address
 433  * @param addrlen where to store the length of the address
 434  * @return GNUNET_OK on success
 435  */
 436 int
 437 GNUNET_CONNECTION_get_address (struct GNUNET_CONNECTION_Handle *sock,
 438                                void **addr, size_t * addrlen)
 439 {
 440   if ((sock->addr == NULL) || (sock->addrlen == 0))
 441     return GNUNET_NO;
 442   *addr = GNUNET_malloc (sock->addrlen);
 443   memcpy (*addr, sock->addr, sock->addrlen);
 444   *addrlen = sock->addrlen;
 445   return GNUNET_OK;
 446 }
 447
 448
 449 /**
 450  * This function is called after establishing a connection either has
 451  * succeeded or timed out.  Note that it is possible that the attempt
 452  * timed out and that we're immediately retrying.  If we are retrying,
 453  * we need to wait again (or timeout); if we succeeded, we need to
 454  * wait for data (or timeout).
 455  *
 456  * @param cls our connection handle
 457  * @param tc task context describing why we are here
 458  */
 459 static void
 460 receive_again (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc);
 461
 462
 463 /**
 464  * Scheduler let us know that the connect task is finished (or was
 465  * cancelled due to shutdown).  Now really clean up.
 466  *
 467  * @param cls our "struct GNUNET_CONNECTION_Handle *"
 468  * @param tc unused
 469  */
 470 static void
 471 destroy_continuation (void *cls,
 472                       const struct GNUNET_SCHEDULER_TaskContext *tc)
 473 {
 474   struct GNUNET_CONNECTION_Handle *sock = cls;
 475   GNUNET_CONNECTION_TransmitReadyNotify notify;
 476   struct AddressProbe *pos;
 477
 478   sock->destroy_task = GNUNET_SCHEDULER_NO_TASK;
 479   GNUNET_assert (sock->dns_active == NULL);
 480   if (0 != (sock->ccs & COCO_TRANSMIT_READY))
 481     {
 482 #if DEBUG_CONNECTION
 483       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 484                   "Destroy waits for CCS-TR to be done (%p)\n", sock);
 485 #endif
 486       sock->ccs |= COCO_DESTROY_CONTINUATION;
 487       return;
 488     }
 489   if (sock->write_task != GNUNET_SCHEDULER_NO_TASK)
 490     {
 491 #if DEBUG_CONNECTION
 492       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 493                   "Destroy waits for write_task to be done (%p)\n", sock);
 494 #endif
 495       GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == sock->destroy_task);
 496       sock->destroy_task
 497         = GNUNET_SCHEDULER_add_after (sock->sched,
 498                                       sock->write_task,
 499                                       &destroy_continuation, sock);
 500       return;
 501     }
 502   if (0 != (sock->ccs & COCO_RECEIVE_AGAIN))
 503     {
 504       sock->ccs |= COCO_DESTROY_CONTINUATION;
 505       return;
 506     }
 507   if (sock->sock != NULL)
 508     {
 509 #if DEBUG_CONNECTION
 510       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 511                   "Shutting down socket (%p)\n", sock);
 512 #endif
 513       if (sock->persist != GNUNET_YES)
 514         GNUNET_NETWORK_socket_shutdown (sock->sock, SHUT_RDWR);
 515     }
 516   if (sock->read_task != GNUNET_SCHEDULER_NO_TASK)
 517     {
 518       GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == sock->destroy_task);
 519       sock->destroy_task
 520         = GNUNET_SCHEDULER_add_after (sock->sched,
 521                                       sock->read_task,
 522                                       &destroy_continuation, sock);
 523       return;
 524     }
 525 #if DEBUG_CONNECTION
 526   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 527               "Destroy actually runs (%p)!\n", sock);
 528 #endif
 529   while (NULL != (pos = sock->ap_head))
 530     {
 531       GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (pos->sock));
 532       GNUNET_SCHEDULER_cancel (sock->sched, pos->task);
 533       GNUNET_CONTAINER_DLL_remove (sock->ap_head, sock->ap_tail, pos);
 534       GNUNET_free (pos);
 535     }
 536   GNUNET_assert (sock->nth.timeout_task == GNUNET_SCHEDULER_NO_TASK);
 537   GNUNET_assert (sock->ccs == COCO_NONE);
 538   if (NULL != (notify = sock->nth.notify_ready))
 539     {
 540       sock->nth.notify_ready = NULL;
 541       notify (sock->nth.notify_ready_cls, 0, NULL);
 542     }
 543
 544   if (sock->sock != NULL)
 545     {
 546       if (sock->persist != GNUNET_YES)
 547         GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (sock->sock));
 548       else
 549         GNUNET_free (sock->sock); /* at least no memory leak (we deliberately
 550                                      leak the socket in this special case) ... */
 551     }
 552   GNUNET_free_non_null (sock->addr);
 553   GNUNET_free_non_null (sock->hostname);
 554   GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == sock->destroy_task);
 555 #if DEBUG_CONNECTION
 556   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 557               "Freeing memory of connection %p.\n", sock);
 558 #endif
 559   GNUNET_free (sock);
 560 }
 561
 562
 563
 564 /**
 565  * See if we are now connected.  If not, wait longer for
 566  * connect to succeed.  If connected, we should be able
 567  * to write now as well, unless we timed out.
 568  *
 569  * @param cls our connection handle
 570  * @param tc task context describing why we are here
 571  */
 572 static void
 573 transmit_ready (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc);
 574
 575
 576 /**
 577  * We've failed for good to establish a connection.
 578  *
 579  * @param h the connection we tried to establish
 580  */
 581 static void
 582 connect_fail_continuation (struct GNUNET_CONNECTION_Handle *h)
 583 {
 584 #if DEBUG_CONNECTION
 585   GNUNET_log ((0 != strncmp (h->hostname,
 586                              "localhost:",
 587                              10))
 588               ? GNUNET_ERROR_TYPE_INFO
 589               : GNUNET_ERROR_TYPE_WARNING,
 590               _("Failed to establish TCP connection to `%s:%u', no further addresses to try.\n"),
 591               h->hostname, h->port);
 592 #endif
 593   /* connect failed / timed out */
 594   GNUNET_break (h->ap_head == NULL);
 595   GNUNET_break (h->ap_tail == NULL);
 596   GNUNET_break (h->dns_active == GNUNET_NO);
 597   GNUNET_break (h->sock == NULL);
 598
 599   /* trigger jobs that used to wait on "connect_task" */
 600   if (0 != (h->ccs & COCO_RECEIVE_AGAIN))
 601     {
 602 #if DEBUG_CONNECTION
 603       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 604                   "connect_fail_continuation triggers receive_again (%p)\n",
 605                   h);
 606 #endif
 607       h->ccs -= COCO_RECEIVE_AGAIN;
 608       h->read_task = GNUNET_SCHEDULER_add_after (h->sched,
 609                                                  GNUNET_SCHEDULER_NO_TASK,
 610                                                  &receive_again, h);
 611     }
 612   if (0 != (h->ccs & COCO_TRANSMIT_READY))
 613     {
 614 #if DEBUG_CONNECTION
 615       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 616                   "connect_fail_continuation cancels timeout_task, triggers transmit_ready (%p)\n",
 617                   h);
 618 #endif
 619       GNUNET_assert (h->nth.timeout_task != GNUNET_SCHEDULER_NO_TASK);
 620       GNUNET_SCHEDULER_cancel (h->sched, h->nth.timeout_task);
 621       h->nth.timeout_task = GNUNET_SCHEDULER_NO_TASK;
 622       h->ccs -= COCO_TRANSMIT_READY;
 623       GNUNET_assert (h->write_task == GNUNET_SCHEDULER_NO_TASK);
 624       h->write_task = GNUNET_SCHEDULER_add_after (h->sched,
 625                                                   GNUNET_SCHEDULER_NO_TASK,
 626                                                   &transmit_ready, h);
 627     }
 628   if (0 != (h->ccs & COCO_DESTROY_CONTINUATION))
 629     {
 630 #if DEBUG_CONNECTION
 631       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 632                   "connect_fail_continuation runs destroy_continuation (%p)\n",
 633                   h);
 634 #endif
 635       h->ccs -= COCO_DESTROY_CONTINUATION;
 636       GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == h->destroy_task);
 637       h->destroy_task
 638         = GNUNET_SCHEDULER_add_now (h->sched,
 639                                     &destroy_continuation,
 640                                     h);
 641     }
 642 }
 643
 644
 645 /**
 646  * We've succeeded in establishing a connection.
 647  *
 648  * @param h the connection we tried to establish
 649  */
 650 static void
 651 connect_success_continuation (struct GNUNET_CONNECTION_Handle *h)
 652 {
 653 #if DEBUG_CONNECTION
 654   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 655               "Connection to `%s' succeeded! (%p)\n",
 656               GNUNET_a2s (h->addr, h->addrlen), h);
 657 #endif
 658   /* trigger jobs that waited for the connection */
 659   if (0 != (h->ccs & COCO_RECEIVE_AGAIN))
 660     {
 661 #if DEBUG_CONNECTION
 662       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 663                   "connect_success_continuation runs receive_again (%p)\n",
 664                   h);
 665 #endif
 666       h->ccs -= COCO_RECEIVE_AGAIN;
 667       h->read_task = GNUNET_SCHEDULER_add_after (h->sched,
 668                                                  GNUNET_SCHEDULER_NO_TASK,
 669                                                  &receive_again, h);
 670     }
 671   if (0 != (h->ccs & COCO_TRANSMIT_READY))
 672     {
 673 #if DEBUG_CONNECTION
 674       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 675                   "connect_success_continuation runs transmit_ready, cancels timeout_task (%p)\n",
 676                   h);
 677 #endif
 678       GNUNET_assert (h->nth.timeout_task != GNUNET_SCHEDULER_NO_TASK);
 679       GNUNET_SCHEDULER_cancel (h->sched, h->nth.timeout_task);
 680       h->nth.timeout_task = GNUNET_SCHEDULER_NO_TASK;
 681       h->ccs -= COCO_TRANSMIT_READY;
 682       GNUNET_assert (h->write_task == GNUNET_SCHEDULER_NO_TASK);
 683       h->write_task =
 684         GNUNET_SCHEDULER_add_write_net (h->sched,
 685                                         GNUNET_TIME_absolute_get_remaining
 686                                         (h->nth.transmit_timeout), h->sock,
 687                                         &transmit_ready, h);
 688     }
 689   if (0 != (h->ccs & COCO_DESTROY_CONTINUATION))
 690     {
 691 #if DEBUG_CONNECTION
 692       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 693                   "connect_success_continuation runs destroy_continuation (%p)\n",
 694                   h);
 695 #endif
 696       h->ccs -= COCO_DESTROY_CONTINUATION;
 697       GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == h->destroy_task);
 698       h->destroy_task
 699         = GNUNET_SCHEDULER_add_now (h->sched,
 700                                     &destroy_continuation,
 701                                     h);
 702     }
 703 }
 704
 705
 706 /**
 707  * Scheduler let us know that we're either ready to write on the
 708  * socket OR connect timed out.  Do the right thing.
 709  *
 710  * @param cls the "struct AddressProbe*" with the address that we are probing
 711  * @param tc success or failure info about the connect attempt.
 712  */
 713 static void
 714 connect_probe_continuation (void *cls,
 715                             const struct GNUNET_SCHEDULER_TaskContext *tc)
 716 {
 717   struct AddressProbe *ap = cls;
 718   struct GNUNET_CONNECTION_Handle *h = ap->h;
 719   struct AddressProbe *pos;
 720   int error;
 721   unsigned int len;
 722
 723   GNUNET_CONTAINER_DLL_remove (h->ap_head, h->ap_tail, ap);
 724   len = sizeof (error);
 725   errno = 0;
 726   error = 0;
 727   if ( (0 == (tc->reason & GNUNET_SCHEDULER_REASON_WRITE_READY)) ||
 728        (GNUNET_OK !=
 729         GNUNET_NETWORK_socket_getsockopt (ap->sock, SOL_SOCKET, SO_ERROR,
 730                                           &error, &len)) ||
 731        (error != 0) )
 732     {
 733       GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (ap->sock));
 734       GNUNET_free (ap);
 735       if ((NULL == h->ap_head) && (h->dns_active == GNUNET_NO))
 736         connect_fail_continuation (h);
 737       return;
 738     }
 739   GNUNET_assert (h->sock == NULL);
 740   GNUNET_assert (ap->sock != NULL);
 741   h->sock = ap->sock;
 742   GNUNET_assert (h->addr == NULL);
 743   h->addr = GNUNET_malloc (ap->addrlen);
 744   memcpy (h->addr, ap->addr, ap->addrlen);
 745   h->addrlen = ap->addrlen;
 746   GNUNET_free (ap);
 747   /* cancel all other attempts */
 748   while (NULL != (pos = h->ap_head))
 749     {
 750       GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (pos->sock));
 751       GNUNET_SCHEDULER_cancel (h->sched, pos->task);
 752       GNUNET_CONTAINER_DLL_remove (h->ap_head, h->ap_tail, pos);
 753       GNUNET_free (pos);
 754     }
 755   connect_success_continuation (h);
 756 }
 757
 758
 759 /**
 760  * Try to establish a socket connection given the specified address.
 761  * This function is called by the resolver once we have a DNS reply.
 762  *
 763  * @param cls our "struct GNUNET_CONNECTION_Handle *"
 764  * @param addr address to try, NULL for "last call"
 765  * @param addrlen length of addr
 766  */
 767 static void
 768 try_connect_using_address (void *cls,
 769                            const struct sockaddr *addr, socklen_t addrlen)
 770 {
 771   struct GNUNET_CONNECTION_Handle *h = cls;
 772   struct AddressProbe *ap;
 773   struct GNUNET_TIME_Relative delay;
 774
 775   if (addr == NULL)
 776     {
 777       h->dns_active = NULL;
 778       if (NULL == h->ap_head)
 779         connect_fail_continuation (h);
 780       return;
 781     }
 782   if (h->sock != NULL)
 783     return;                     /* already connected */
 784   GNUNET_assert (h->addr == NULL);
 785   /* try to connect */
 786 #if DEBUG_CONNECTION
 787   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 788               "Trying to connect using address `%s:%u/%s:%u'\n",
 789               h->hostname, h->port, GNUNET_a2s (addr, addrlen), h->port);
 790 #endif
 791   ap = GNUNET_malloc (sizeof (struct AddressProbe) + addrlen);
 792   ap->addr = (const struct sockaddr *) &ap[1];
 793   memcpy (&ap[1], addr, addrlen);
 794   ap->addrlen = addrlen;
 795   ap->h = h;
 796
 797   switch (ap->addr->sa_family)
 798     {
 799     case AF_INET:
 800       ((struct sockaddr_in *) ap->addr)->sin_port = htons (h->port);
 801       break;
 802     case AF_INET6:
 803       ((struct sockaddr_in6 *) ap->addr)->sin6_port = htons (h->port);
 804       break;
 805     default:
 806       GNUNET_break (0);
 807       GNUNET_free (ap);
 808       return;                   /* not supported by us */
 809     }
 810   ap->sock =
 811     GNUNET_NETWORK_socket_create (ap->addr->sa_family, SOCK_STREAM, 0);
 812   if (ap->sock == NULL)
 813     {
 814       GNUNET_free (ap);
 815       return;                   /* not supported by OS */
 816     }
 817 #if DEBUG_CONNECTION
 818   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 819               _("Trying to connect to `%s' (%p)\n"),
 820               GNUNET_a2s (ap->addr, ap->addrlen), h);
 821 #endif
 822   if ((GNUNET_OK != GNUNET_NETWORK_socket_connect (ap->sock,
 823                                                    ap->addr,
 824                                                    ap->addrlen)) &&
 825       (errno != EINPROGRESS))
 826     {
 827       /* maybe refused / unsupported address, try next */
 828       GNUNET_log_strerror (GNUNET_ERROR_TYPE_INFO, "connect");
 829       GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (ap->sock));
 830       GNUNET_free (ap);
 831       return;
 832     }
 833   GNUNET_CONTAINER_DLL_insert (h->ap_head, h->ap_tail, ap);
 834   delay = GNUNET_CONNECTION_CONNECT_RETRY_TIMEOUT;
 835   if (h->nth.notify_ready != NULL)
 836     delay = GNUNET_TIME_relative_min (delay,
 837                                       GNUNET_TIME_absolute_get_remaining
 838                                       (h->nth.transmit_timeout));
 839   if (h->receiver != NULL)
 840     delay = GNUNET_TIME_relative_min (delay,
 841                                       GNUNET_TIME_absolute_get_remaining
 842                                       (h->receive_timeout));
 843   ap->task =
 844     GNUNET_SCHEDULER_add_write_net (h->sched, delay, ap->sock,
 845                                     &connect_probe_continuation, ap);
 846 }
 847
 848
 849 /**
 850  * Create a socket handle by (asynchronously) connecting to a host.
 851  * This function returns immediately, even if the connection has not
 852  * yet been established.  This function only creates TCP connections.
 853  *
 854  * @param sched scheduler to use
 855  * @param cfg configuration to use
 856  * @param hostname name of the host to connect to
 857  * @param port port to connect to
 858  * @return the socket handle
 859  */
 860 struct GNUNET_CONNECTION_Handle *
 861 GNUNET_CONNECTION_create_from_connect (struct GNUNET_SCHEDULER_Handle *sched,
 862                                        const struct
 863                                        GNUNET_CONFIGURATION_Handle *cfg,
 864                                        const char *hostname, uint16_t port)
 865 {
 866   struct GNUNET_CONNECTION_Handle *ret;
 867
 868   GNUNET_assert (0 < strlen (hostname));        /* sanity check */
 869   ret = GNUNET_malloc (sizeof (struct GNUNET_CONNECTION_Handle));
 870   ret->cfg = cfg;
 871   ret->sched = sched;
 872   ret->write_buffer_size = GNUNET_SERVER_MIN_BUFFER_SIZE;
 873   ret->write_buffer = GNUNET_malloc(ret->write_buffer_size);
 874   ret->port = port;
 875   ret->hostname = GNUNET_strdup (hostname);
 876   ret->dns_active = GNUNET_RESOLVER_ip_get (sched,
 877                                             cfg,
 878                                             ret->hostname,
 879                                             AF_UNSPEC,
 880                                             GNUNET_CONNECTION_CONNECT_RETRY_TIMEOUT,
 881                                             &try_connect_using_address, ret);
 882   return ret;
 883 }
 884
 885
 886 /**
 887  * Create a socket handle by connecting to a UNIX domain service.
 888  * This function returns immediately, even if the connection has not
 889  * yet been established.  This function only creates UNIX connections.
 890  *
 891  * @param sched scheduler to use
 892  * @param cfg configuration to use
 893  * @param unixpath path to connect to
 894  * @return the socket handle, NULL on systems without UNIX support
 895  */
 896 struct GNUNET_CONNECTION_Handle *
 897 GNUNET_CONNECTION_create_from_connect_to_unixpath (struct GNUNET_SCHEDULER_Handle *sched,
 898                                                    const struct
 899                                                    GNUNET_CONFIGURATION_Handle *cfg,
 900                                                    const char *unixpath)
 901 {
 902 #ifdef AF_UNIX
 903   struct GNUNET_CONNECTION_Handle *ret;
 904   struct sockaddr_un *un;
 905   size_t slen;
 906
 907   GNUNET_assert (0 < strlen (unixpath));        /* sanity check */
 908   un = GNUNET_malloc (sizeof (struct sockaddr_un));
 909   un->sun_family = AF_UNIX;
 910   slen = strlen (unixpath) + 1;
 911   if (slen >= sizeof (un->sun_path))
 912     slen = sizeof (un->sun_path) - 1;
 913   memcpy (un->sun_path,
 914           unixpath,
 915           slen);
 916   un->sun_path[slen] = '\0';
 917   slen += sizeof (sa_family_t);
 918 #if LINUX
 919   un->sun_path[0] = '\0';
 920   slen = sizeof (struct sockaddr_un);
 921 #endif
 922   ret = GNUNET_malloc (sizeof (struct GNUNET_CONNECTION_Handle));
 923   ret->cfg = cfg;
 924   ret->sched = sched;
 925   ret->write_buffer_size = GNUNET_SERVER_MIN_BUFFER_SIZE;
 926   ret->write_buffer = GNUNET_malloc(ret->write_buffer_size);
 927   ret->port = 0;
 928   ret->hostname = NULL;
 929   ret->addr = (struct sockaddr*) un;
 930   ret->addrlen = slen;
 931   ret->sock = GNUNET_NETWORK_socket_create (AF_UNIX, SOCK_STREAM, 0);
 932   if (NULL == ret->sock)
 933     {
 934       GNUNET_free (ret->addr);
 935       GNUNET_free (ret->write_buffer);
 936       GNUNET_free (ret);
 937       return NULL;
 938     }
 939   if (GNUNET_OK != GNUNET_NETWORK_socket_connect (ret->sock,
 940                                                   ret->addr,
 941                                                   ret->addrlen))
 942     {
 943       GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (ret->sock));
 944       GNUNET_free (ret->addr);
 945       GNUNET_free (ret->write_buffer);
 946       GNUNET_free (ret);
 947       return NULL;
 948     }
 949   connect_success_continuation (ret);
 950   return ret;
 951 #else
 952   return NULL;
 953 #endif
 954 }
 955
 956
 957 /**
 958  * Create a socket handle by (asynchronously) connecting to a host.
 959  * This function returns immediately, even if the connection has not
 960  * yet been established.  This function only creates TCP connections.
 961  *
 962  * @param sched scheduler to use
 963  * @param af_family address family to use
 964  * @param serv_addr server address
 965  * @param addrlen length of server address
 966  * @return the socket handle
 967  */
 968 struct GNUNET_CONNECTION_Handle *
 969 GNUNET_CONNECTION_create_from_sockaddr (struct GNUNET_SCHEDULER_Handle
 970                                         *sched, int af_family,
 971                                         const struct sockaddr *serv_addr,
 972                                         socklen_t addrlen)
 973 {
 974   struct GNUNET_NETWORK_Handle *s;
 975   struct GNUNET_CONNECTION_Handle *ret;
 976
 977   s = GNUNET_NETWORK_socket_create (af_family, SOCK_STREAM, 0);
 978   if (s == NULL)
 979     {
 980       GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING |
 981                            GNUNET_ERROR_TYPE_BULK, "socket");
 982       return NULL;
 983     }
 984   if ((GNUNET_OK != GNUNET_NETWORK_socket_connect (s, serv_addr, addrlen))
 985       && (errno != EINPROGRESS))
 986     {
 987       /* maybe refused / unsupported address, try next */
 988       GNUNET_log_strerror (GNUNET_ERROR_TYPE_INFO, "connect");
 989       GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (s));
 990       return NULL;
 991     }
 992   ret = GNUNET_CONNECTION_create_from_existing (sched, s);
 993   ret->addr = GNUNET_malloc (addrlen);
 994   memcpy (ret->addr, serv_addr, addrlen);
 995   ret->addrlen = addrlen;
 996 #if DEBUG_CONNECTION
 997   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 998               _("Trying to connect to `%s' (%p)\n"),
 999               GNUNET_a2s (serv_addr, addrlen), ret);
1000 #endif
1001   return ret;
1002 }
1003
1004
1005 /**
1006  * Check if socket is valid (no fatal errors have happened so far).
1007  * Note that a socket that is still trying to connect is considered
1008  * valid.
1009  *
1010  * @param sock socket to check
1011  * @return GNUNET_YES if valid, GNUNET_NO otherwise
1012  */
1013 int
1014 GNUNET_CONNECTION_check (struct GNUNET_CONNECTION_Handle *sock)
1015 {
1016   if ((sock->ap_head != NULL) || (sock->dns_active != NULL))
1017     return GNUNET_YES;          /* still trying to connect */
1018   return (sock->sock == NULL) ? GNUNET_NO : GNUNET_YES;
1019 }
1020
1021
1022 /**
1023  * Close the socket and free associated resources. Pending
1024  * transmissions may be completed or dropped depending on the
1025  * arguments.   If a receive call is pending and should
1026  * NOT be completed, 'GNUNET_CONNECTION_receive_cancel'
1027  * should be called explicitly first.
1028  *
1029  * @param sock socket to destroy
1030  * @param finish_pending_write should pending writes be completed or aborted?
1031  *        (this applies to transmissions where the data has already been
1032  *        read from the application; all other transmissions should be
1033  *        aborted using 'GNUNET_CONNECTION_notify_transmit_ready_cancel').
1034  */
1035 void
1036 GNUNET_CONNECTION_destroy (struct GNUNET_CONNECTION_Handle *sock,
1037                            int finish_pending_write)
1038 {
1039   if (GNUNET_NO == finish_pending_write)
1040     {
1041       if (sock->write_task != GNUNET_SCHEDULER_NO_TASK)
1042         {
1043           GNUNET_SCHEDULER_cancel (sock->sched,
1044                                    sock->write_task);
1045           sock->write_task = GNUNET_SCHEDULER_NO_TASK;
1046           sock->write_buffer_off = 0;
1047         }
1048     }
1049   if ((sock->write_buffer_off == 0) && (sock->dns_active != NULL))
1050     {
1051       GNUNET_RESOLVER_request_cancel (sock->dns_active);
1052       sock->dns_active = NULL;
1053     }
1054   GNUNET_assert (sock->sched != NULL);
1055   GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == sock->destroy_task);
1056   sock->destroy_task
1057     = GNUNET_SCHEDULER_add_now (sock->sched,
1058                                 &destroy_continuation, sock);
1059 }
1060
1061
1062 /**
1063  * Tell the receiver callback that a timeout was reached.
1064  */
1065 static void
1066 signal_timeout (struct GNUNET_CONNECTION_Handle *sh)
1067 {
1068   GNUNET_CONNECTION_Receiver receiver;
1069
1070 #if DEBUG_CONNECTION
1071   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1072               "Network signals time out to receiver (%p)!\n", sh);
1073 #endif
1074   GNUNET_assert (NULL != (receiver = sh->receiver));
1075   sh->receiver = NULL;
1076   receiver (sh->receiver_cls, NULL, 0, NULL, 0, 0);
1077 }
1078
1079
1080 /**
1081  * Tell the receiver callback that we had an IO error.
1082  */
1083 static void
1084 signal_error (struct GNUNET_CONNECTION_Handle *sh, int errcode)
1085 {
1086   GNUNET_CONNECTION_Receiver receiver;
1087   GNUNET_assert (NULL != (receiver = sh->receiver));
1088   sh->receiver = NULL;
1089   receiver (sh->receiver_cls, NULL, 0, sh->addr, sh->addrlen, errcode);
1090 }
1091
1092
1093 /**
1094  * This function is called once we either timeout
1095  * or have data ready to read.
1096  */
1097 static void
1098 receive_ready (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1099 {
1100   struct GNUNET_CONNECTION_Handle *sh = cls;
1101   struct GNUNET_TIME_Absolute now;
1102   char buffer[sh->max];
1103   ssize_t ret;
1104   GNUNET_CONNECTION_Receiver receiver;
1105
1106   sh->read_task = GNUNET_SCHEDULER_NO_TASK;
1107   if ( (GNUNET_YES == sh->ignore_shutdown) &&
1108        (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)))
1109     {
1110       /* ignore shutdown request, go again immediately */
1111 #if DEBUG_CONNECTION
1112       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1113                   "Ignoring shutdown signal per configuration\n");
1114 #endif
1115       sh->read_task = GNUNET_SCHEDULER_add_read_net (tc->sched,
1116                                                      GNUNET_TIME_absolute_get_remaining
1117                                                      (sh->receive_timeout),
1118                                                      sh->sock,
1119                                                      &receive_ready, sh);
1120       return;
1121     }
1122   now = GNUNET_TIME_absolute_get ();
1123   if ((now.value > sh->receive_timeout.value) ||
1124       (0 != (tc->reason & GNUNET_SCHEDULER_REASON_TIMEOUT)) ||
1125       (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)))
1126     {
1127 #if DEBUG_CONNECTION
1128       if (0 == (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
1129         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1130                     "Receive from `%s' encounters error: time out by %llums... (%p)\n",
1131                     GNUNET_a2s (sh->addr, sh->addrlen),
1132                     GNUNET_TIME_absolute_get_duration (sh->receive_timeout).
1133                     value, sh);
1134 #endif
1135       signal_timeout (sh);
1136       return;
1137     }
1138   if (sh->sock == NULL)
1139     {
1140       /* connect failed for good */
1141 #if DEBUG_CONNECTION
1142       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1143                   "Receive encounters error, socket closed... (%p)\n", sh);
1144 #endif
1145       signal_error (sh, ECONNREFUSED);
1146       return;
1147     }
1148   GNUNET_assert (GNUNET_NETWORK_fdset_isset (tc->read_ready, sh->sock));
1149 RETRY:
1150   ret = GNUNET_NETWORK_socket_recv (sh->sock, buffer, sh->max);
1151   if (ret == -1)
1152     {
1153       if (errno == EINTR)
1154         goto RETRY;
1155 #if DEBUG_CONNECTION
1156       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1157                   "Error receiving: %s\n", STRERROR (errno));
1158 #endif
1159       signal_error (sh, errno);
1160       return;
1161     }
1162 #if DEBUG_CONNECTION
1163   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1164               "receive_ready read %u/%u bytes from `%s' (%p)!\n",
1165               (unsigned int) ret,
1166               sh->max, GNUNET_a2s (sh->addr, sh->addrlen), sh);
1167 #endif
1168   GNUNET_assert (NULL != (receiver = sh->receiver));
1169   sh->receiver = NULL;
1170   receiver (sh->receiver_cls, buffer, ret, sh->addr, sh->addrlen, 0);
1171 }
1172
1173
1174 /**
1175  * This function is called after establishing a connection either has
1176  * succeeded or timed out.  Note that it is possible that the attempt
1177  * timed out and that we're immediately retrying.  If we are retrying,
1178  * we need to wait again (or timeout); if we succeeded, we need to
1179  * wait for data (or timeout).
1180  *
1181  * @param cls our connection handle
1182  * @param tc task context describing why we are here
1183  */
1184 static void
1185 receive_again (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1186 {
1187   struct GNUNET_CONNECTION_Handle *sh = cls;
1188   struct GNUNET_TIME_Absolute now;
1189
1190   sh->read_task = GNUNET_SCHEDULER_NO_TASK;
1191   if (sh->sock == NULL)
1192     {
1193       /* not connected and no longer trying */
1194 #if DEBUG_CONNECTION
1195       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1196                   "Receive encounters error, socket closed (%p)...\n", sh);
1197 #endif
1198       signal_error (sh, ECONNREFUSED);
1199       return;
1200     }
1201   now = GNUNET_TIME_absolute_get ();
1202   if ((now.value > sh->receive_timeout.value) ||
1203       (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)))
1204     {
1205 #if DEBUG_CONNECTION
1206       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1207                   "Receive encounters error: time out (%p)...\n", sh);
1208 #endif
1209       signal_timeout (sh);
1210       return;
1211     }
1212   GNUNET_assert (sh->sock != NULL);
1213   /* connect succeeded, wait for data! */
1214   sh->read_task = GNUNET_SCHEDULER_add_read_net (tc->sched,
1215                                                  GNUNET_TIME_absolute_get_remaining
1216                                                  (sh->receive_timeout),
1217                                                  sh->sock,
1218                                                  &receive_ready, sh);
1219 }
1220
1221
1222 /**
1223  * Receive data from the given socket.  Note that this function will
1224  * call "receiver" asynchronously using the scheduler.  It will
1225  * "immediately" return.  Note that there MUST only be one active
1226  * receive call per socket at any given point in time (so do not
1227  * call receive again until the receiver callback has been invoked).
1228  *
1229  * @param sock socket handle
1230  * @param max maximum number of bytes to read
1231  * @param timeout maximum amount of time to wait (use -1 for "forever")
1232  * @param receiver function to call with received data
1233  * @param receiver_cls closure for receiver
1234  */
1235 void
1236 GNUNET_CONNECTION_receive (struct GNUNET_CONNECTION_Handle *sock,
1237                            size_t max,
1238                            struct GNUNET_TIME_Relative timeout,
1239                            GNUNET_CONNECTION_Receiver receiver,
1240                            void *receiver_cls)
1241 {
1242   struct GNUNET_SCHEDULER_TaskContext tc;
1243
1244   GNUNET_assert ((sock->read_task == GNUNET_SCHEDULER_NO_TASK) &&
1245                  (0 == (sock->ccs & COCO_RECEIVE_AGAIN)) &&
1246                  (sock->receiver == NULL));
1247   sock->receiver = receiver;
1248   sock->receiver_cls = receiver_cls;
1249   sock->receive_timeout = GNUNET_TIME_relative_to_absolute (timeout);
1250   sock->max = max;
1251   if (sock->sock != NULL)
1252     {
1253       memset (&tc, 0, sizeof (tc));
1254       tc.sched = sock->sched;
1255       tc.reason = GNUNET_SCHEDULER_REASON_PREREQ_DONE;
1256       receive_again (sock, &tc);
1257       return;
1258     }
1259   if ((sock->dns_active == NULL) && (sock->ap_head == NULL))
1260     {
1261       receiver (receiver_cls, NULL, 0, NULL, 0, ETIMEDOUT);
1262       return;
1263     }
1264   sock->ccs += COCO_RECEIVE_AGAIN;
1265 }
1266
1267
1268 /**
1269  * Configure this connection to ignore shutdown signals.
1270  *
1271  * @param sock socket handle
1272  * @param do_ignore GNUNET_YES to ignore, GNUNET_NO to restore default
1273  */
1274 void
1275 GNUNET_CONNECTION_ignore_shutdown (struct GNUNET_CONNECTION_Handle *sock,
1276                                    int do_ignore)
1277 {
1278   sock->ignore_shutdown = do_ignore;
1279 }
1280
1281
1282 /**
1283  * Cancel receive job on the given socket.  Note that the
1284  * receiver callback must not have been called yet in order
1285  * for the cancellation to be valid.
1286  *
1287  * @param sock socket handle
1288  * @return closure of the original receiver callback closure
1289  */
1290 void *
1291 GNUNET_CONNECTION_receive_cancel (struct GNUNET_CONNECTION_Handle *sock)
1292 {
1293   if (sock->read_task != GNUNET_SCHEDULER_NO_TASK)
1294     {
1295       GNUNET_assert (sock == GNUNET_SCHEDULER_cancel (sock->sched,
1296                                                       sock->read_task));
1297       sock->read_task = GNUNET_SCHEDULER_NO_TASK;
1298     }
1299   else
1300     {
1301       GNUNET_assert (0 != (sock->ccs & COCO_RECEIVE_AGAIN));
1302       sock->ccs -= COCO_RECEIVE_AGAIN;
1303     }
1304   sock->receiver = NULL;
1305   return sock->receiver_cls;
1306 }
1307
1308
1309 /**
1310  * Try to call the transmit notify method (check if we do
1311  * have enough space available first)!
1312  *
1313  * @param sock socket for which we should do this processing
1314  * @return GNUNET_YES if we were able to call notify
1315  */
1316 static int
1317 process_notify (struct GNUNET_CONNECTION_Handle *sock)
1318 {
1319   size_t used;
1320   size_t avail;
1321   size_t size;
1322   GNUNET_CONNECTION_TransmitReadyNotify notify;
1323
1324   GNUNET_assert (sock->write_task == GNUNET_SCHEDULER_NO_TASK);
1325   if (NULL == (notify = sock->nth.notify_ready))
1326     return GNUNET_NO;
1327   used = sock->write_buffer_off - sock->write_buffer_pos;
1328   avail = sock->write_buffer_size - used;
1329   size = sock->nth.notify_size;
1330   if (sock->nth.notify_size > avail)
1331     return GNUNET_NO;
1332   sock->nth.notify_ready = NULL;
1333   if (sock->write_buffer_size - sock->write_buffer_off < size)
1334     {
1335       /* need to compact */
1336       memmove (sock->write_buffer,
1337                &sock->write_buffer[sock->write_buffer_pos], used);
1338       sock->write_buffer_off -= sock->write_buffer_pos;
1339       sock->write_buffer_pos = 0;
1340     }
1341   GNUNET_assert (sock->write_buffer_size - sock->write_buffer_off >= size);
1342   size = notify (sock->nth.notify_ready_cls,
1343                  sock->write_buffer_size - sock->write_buffer_off,
1344                  &sock->write_buffer[sock->write_buffer_off]);
1345   sock->write_buffer_off += size;
1346   return GNUNET_YES;
1347 }
1348
1349
1350 /**
1351  * Task invoked by the scheduler when a call to transmit
1352  * is timing out (we never got enough buffer space to call
1353  * the callback function before the specified timeout
1354  * expired).
1355  *
1356  * This task notifies the client about the timeout.
1357  */
1358 static void
1359 transmit_timeout (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1360 {
1361   struct GNUNET_CONNECTION_Handle *sock = cls;
1362   GNUNET_CONNECTION_TransmitReadyNotify notify;
1363
1364 #if DEBUG_CONNECTION
1365   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1366               "transmit_timeout running (%p)\n", sock);
1367 #endif
1368   sock->nth.timeout_task = GNUNET_SCHEDULER_NO_TASK;
1369 #if DEBUG_CONNECTION
1370   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1371               "Transmit to `%s:%u/%s' fails, time out reached (%p).\n",
1372               sock->hostname,
1373               sock->port, GNUNET_a2s (sock->addr, sock->addrlen), sock);
1374 #endif
1375   GNUNET_assert (0 != (sock->ccs & COCO_TRANSMIT_READY));
1376   sock->ccs -= COCO_TRANSMIT_READY;     /* remove request */
1377   notify = sock->nth.notify_ready;
1378   sock->nth.notify_ready = NULL;
1379   notify (sock->nth.notify_ready_cls, 0, NULL);
1380 }
1381
1382
1383 /**
1384  * Task invoked by the scheduler when we failed to connect
1385  * at the time of being asked to transmit.
1386  *
1387  * This task notifies the client about the error.
1388  */
1389 static void
1390 connect_error (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1391 {
1392   struct GNUNET_CONNECTION_Handle *sock = cls;
1393   GNUNET_CONNECTION_TransmitReadyNotify notify;
1394
1395 #if DEBUG_CONNECTION
1396   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1397               "Transmission request of size %u fails, connection failed (%p).\n",
1398               sock->nth.notify_size, sock);
1399 #endif
1400   sock->write_task = GNUNET_SCHEDULER_NO_TASK;
1401   notify = sock->nth.notify_ready;
1402   sock->nth.notify_ready = NULL;
1403   notify (sock->nth.notify_ready_cls, 0, NULL);
1404 }
1405
1406
1407 static void
1408 transmit_error (struct GNUNET_CONNECTION_Handle *sock)
1409 {
1410   GNUNET_CONNECTION_TransmitReadyNotify notify;
1411
1412   if (NULL != sock->sock)
1413     {
1414       GNUNET_NETWORK_socket_shutdown (sock->sock, SHUT_RDWR);
1415       GNUNET_break (GNUNET_OK ==
1416                     GNUNET_NETWORK_socket_close (sock->sock));
1417       sock->sock = NULL;
1418     }
1419   if (sock->read_task != GNUNET_SCHEDULER_NO_TASK)
1420     {
1421       GNUNET_SCHEDULER_cancel (sock->sched,
1422                                sock->read_task);
1423       sock->read_task = GNUNET_SCHEDULER_NO_TASK;
1424       signal_timeout (sock);
1425       return;
1426     }
1427   if (sock->nth.notify_ready == NULL)
1428     return;                     /* nobody to tell about it */
1429   notify = sock->nth.notify_ready;
1430   sock->nth.notify_ready = NULL;
1431   notify (sock->nth.notify_ready_cls, 0, NULL);
1432 }
1433
1434
1435 /**
1436  * See if we are now connected.  If not, wait longer for
1437  * connect to succeed.  If connected, we should be able
1438  * to write now as well, unless we timed out.
1439  *
1440  * @param cls our connection handle
1441  * @param tc task context describing why we are here
1442  */
1443 static void
1444 transmit_ready (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1445 {
1446   struct GNUNET_CONNECTION_Handle *sock = cls;
1447   GNUNET_CONNECTION_TransmitReadyNotify notify;
1448   ssize_t ret;
1449   size_t have;
1450
1451 #if DEBUG_CONNECTION
1452   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1453               "transmit_ready running (%p).\n", sock);
1454 #endif
1455   GNUNET_assert (sock->write_task != GNUNET_SCHEDULER_NO_TASK);
1456   sock->write_task = GNUNET_SCHEDULER_NO_TASK;
1457   GNUNET_assert (sock->nth.timeout_task == GNUNET_SCHEDULER_NO_TASK);
1458   if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
1459     {
1460       if (sock->ignore_shutdown == GNUNET_YES)
1461         goto SCHEDULE_WRITE;    /* ignore shutdown, go again immediately */
1462 #if DEBUG_CONNECTION
1463       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1464                   "Transmit to `%s' fails, shutdown happened (%p).\n",
1465                   GNUNET_a2s (sock->addr, sock->addrlen), sock);
1466 #endif
1467       notify = sock->nth.notify_ready;
1468       sock->nth.notify_ready = NULL;
1469       notify (sock->nth.notify_ready_cls, 0, NULL);
1470       return;
1471     }
1472   if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_TIMEOUT))
1473     {
1474 #if DEBUG_CONNECTION
1475       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1476                   "Transmit to `%s' fails, time out reached (%p).\n",
1477                   GNUNET_a2s (sock->addr, sock->addrlen), sock);
1478 #endif
1479       notify = sock->nth.notify_ready;
1480       sock->nth.notify_ready = NULL;
1481       notify (sock->nth.notify_ready_cls, 0, NULL);
1482       return;
1483     }
1484   GNUNET_assert (NULL != sock->sock);
1485   if (tc->write_ready == NULL)
1486     {
1487       /* special circumstances (in particular,
1488          PREREQ_DONE after connect): not yet ready to write,
1489          but no "fatal" error either.  Hence retry.  */
1490       goto SCHEDULE_WRITE;
1491     }
1492   if (!GNUNET_NETWORK_fdset_isset (tc->write_ready, sock->sock))
1493     {
1494 #if DEBUG_CONNECTION
1495       GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1496                   _
1497                   ("Could not satisfy pending transmission request, socket closed or connect failed (%p).\n"),
1498                   sock);
1499 #endif
1500       transmit_error (sock);
1501       return;                   /* connect failed for good, we're finished */
1502     }
1503   GNUNET_assert (sock->write_buffer_off >= sock->write_buffer_pos);
1504   process_notify (sock);
1505   have = sock->write_buffer_off - sock->write_buffer_pos;
1506   if (have == 0)
1507     {
1508       /* no data ready for writing, terminate write loop */
1509       return;
1510     }
1511   GNUNET_assert (have <= sock->write_buffer_size);
1512   GNUNET_assert (have + sock->write_buffer_pos <= sock->write_buffer_size);
1513   GNUNET_assert (sock->write_buffer_pos <= sock->write_buffer_size);
1514 RETRY:
1515   ret = GNUNET_NETWORK_socket_send (sock->sock,
1516                                     &sock->write_buffer[sock->
1517                                                         write_buffer_pos],
1518                                     have);
1519   if (ret == -1)
1520     {
1521       if (errno == EINTR)
1522         goto RETRY;
1523 #if 0
1524       int en = errno;
1525       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1526                   _("Failed to send to `%s': %s\n"),
1527                   GNUNET_a2s (sock->addr,
1528                               sock->addrlen),
1529                   STRERROR (en));
1530 #endif
1531 #if DEBUG_CONNECTION
1532       GNUNET_log_strerror (GNUNET_ERROR_TYPE_DEBUG, "send");
1533 #endif
1534       transmit_error (sock);
1535       return;
1536     }
1537 #if DEBUG_CONNECTION
1538   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1539               "transmit_ready transmitted %u/%u bytes to `%s' (%p)\n",
1540               (unsigned int) ret,
1541               have, GNUNET_a2s (sock->addr, sock->addrlen), sock);
1542 #endif
1543   sock->write_buffer_pos += ret;
1544   if (sock->write_buffer_pos == sock->write_buffer_off)
1545     {
1546       /* transmitted all pending data */
1547       sock->write_buffer_pos = 0;
1548       sock->write_buffer_off = 0;
1549     }
1550   if ((sock->write_buffer_off == 0) && (NULL == sock->nth.notify_ready))
1551     return;                     /* all data sent! */
1552   /* not done writing, schedule more */
1553 SCHEDULE_WRITE:
1554 #if DEBUG_CONNECTION
1555   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1556               "Re-scheduling transmit_ready (more to do) (%p).\n", sock);
1557 #endif
1558   if (sock->write_task == GNUNET_SCHEDULER_NO_TASK)
1559     sock->write_task =
1560       GNUNET_SCHEDULER_add_write_net (tc->sched,
1561                                       GNUNET_TIME_absolute_get_remaining
1562                                       (sock->nth.transmit_timeout),
1563                                       sock->sock, &transmit_ready, sock);
1564 }
1565
1566
1567 /**
1568  * Ask the socket to call us once the specified number of bytes
1569  * are free in the transmission buffer.  May call the notify
1570  * method immediately if enough space is available.
1571  *
1572  * @param sock socket
1573  * @param size number of bytes to send
1574  * @param timeout after how long should we give up (and call
1575  *        notify with buf NULL and size 0)?
1576  * @param notify function to call
1577  * @param notify_cls closure for notify
1578  * @return non-NULL if the notify callback was queued,
1579  *         NULL if we are already going to notify someone else (busy)
1580  */
1581 struct GNUNET_CONNECTION_TransmitHandle *
1582 GNUNET_CONNECTION_notify_transmit_ready (struct GNUNET_CONNECTION_Handle
1583                                          *sock, size_t size,
1584                                          struct GNUNET_TIME_Relative timeout,
1585                                          GNUNET_CONNECTION_TransmitReadyNotify
1586                                          notify, void *notify_cls)
1587 {
1588   size_t temp_size;
1589   if (sock->nth.notify_ready != NULL)
1590     return NULL;
1591   GNUNET_assert (notify != NULL);
1592   if ((sock->write_buffer_size < size) && (size < GNUNET_SERVER_MAX_MESSAGE_SIZE))
1593     {
1594       temp_size = sock->write_buffer_size + size;
1595       if (temp_size >= GNUNET_SERVER_MAX_MESSAGE_SIZE)
1596         temp_size = GNUNET_SERVER_MAX_MESSAGE_SIZE;
1597
1598       sock->write_buffer = GNUNET_realloc(sock->write_buffer, temp_size);
1599       sock->write_buffer_size = temp_size;
1600     }
1601   GNUNET_assert (sock->write_buffer_size >= size);
1602   GNUNET_assert (sock->write_buffer_off <= sock->write_buffer_size);
1603   GNUNET_assert (sock->write_buffer_pos <= sock->write_buffer_size);
1604   GNUNET_assert (sock->write_buffer_pos <= sock->write_buffer_off);
1605   sock->nth.notify_ready = notify;
1606   sock->nth.notify_ready_cls = notify_cls;
1607   sock->nth.sh = sock;
1608   sock->nth.notify_size = size;
1609   sock->nth.transmit_timeout = GNUNET_TIME_relative_to_absolute (timeout);
1610   GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == sock->nth.timeout_task);
1611   if ((sock->sock == NULL) &&
1612       (sock->ap_head == NULL) && (sock->dns_active == NULL))
1613     {
1614       if (sock->write_task != GNUNET_SCHEDULER_NO_TASK)
1615         GNUNET_SCHEDULER_cancel (sock->sched,
1616                                  sock->write_task);
1617       sock->write_task = GNUNET_SCHEDULER_add_now (sock->sched,
1618                                                    &connect_error, sock);
1619       return &sock->nth;
1620     }
1621   if (GNUNET_SCHEDULER_NO_TASK != sock->write_task)
1622     return &sock->nth;
1623   if (sock->sock != NULL)
1624     {
1625 #if DEBUG_CONNECTION
1626       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1627                   "Scheduling transmit_ready (%p).\n", sock);
1628 #endif
1629       sock->write_task = GNUNET_SCHEDULER_add_write_net (sock->sched,
1630                                                          GNUNET_TIME_absolute_get_remaining
1631                                                          (sock->nth.
1632                                                           transmit_timeout),
1633                                                          sock->sock,
1634                                                          &transmit_ready,
1635                                                          sock);
1636     }
1637   else
1638     {
1639 #if DEBUG_CONNECTION
1640       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1641                   "CCS-Scheduling transmit_ready, adding timeout task (%p).\n",
1642                   sock);
1643 #endif
1644       sock->ccs |= COCO_TRANSMIT_READY;
1645       sock->nth.timeout_task = GNUNET_SCHEDULER_add_delayed (sock->sched,
1646                                                              timeout,
1647                                                              &transmit_timeout,
1648                                                              sock);
1649     }
1650   return &sock->nth;
1651 }
1652
1653
1654 /**
1655  * Cancel the specified transmission-ready
1656  * notification.
1657  */
1658 void
1659 GNUNET_CONNECTION_notify_transmit_ready_cancel (struct
1660                                                 GNUNET_CONNECTION_TransmitHandle
1661                                                 *h)
1662 {
1663   GNUNET_assert (h->notify_ready != NULL);
1664   if (0 != (h->sh->ccs & COCO_TRANSMIT_READY))
1665     {
1666 #if DEBUG_CONNECTION
1667       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1668                   "notify_transmit_ready_cancel cancels timeout_task (%p)\n",
1669                   h);
1670 #endif
1671       GNUNET_SCHEDULER_cancel (h->sh->sched, h->timeout_task);
1672       h->timeout_task = GNUNET_SCHEDULER_NO_TASK;
1673       h->sh->ccs -= COCO_TRANSMIT_READY;
1674     }
1675   else
1676     {
1677       if (h->sh->write_task != GNUNET_SCHEDULER_NO_TASK)
1678         {
1679           GNUNET_SCHEDULER_cancel (h->sh->sched, h->sh->write_task);
1680           h->sh->write_task = GNUNET_SCHEDULER_NO_TASK;
1681         }
1682     }
1683   h->notify_ready = NULL;
1684 }
1685
1686 /* end of connection.c */