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->write_buffer);
 560   GNUNET_free (sock);
 561 }
 562
 563
 564
 565 /**
 566  * See if we are now connected.  If not, wait longer for
 567  * connect to succeed.  If connected, we should be able
 568  * to write now as well, unless we timed out.
 569  *
 570  * @param cls our connection handle
 571  * @param tc task context describing why we are here
 572  */
 573 static void
 574 transmit_ready (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc);
 575
 576
 577 /**
 578  * We've failed for good to establish a connection.
 579  *
 580  * @param h the connection we tried to establish
 581  */
 582 static void
 583 connect_fail_continuation (struct GNUNET_CONNECTION_Handle *h)
 584 {
 585 #if DEBUG_CONNECTION
 586   GNUNET_log ((0 != strncmp (h->hostname,
 587                              "localhost:",
 588                              10))
 589               ? GNUNET_ERROR_TYPE_INFO
 590               : GNUNET_ERROR_TYPE_WARNING,
 591               _("Failed to establish TCP connection to `%s:%u', no further addresses to try.\n"),
 592               h->hostname, h->port);
 593 #endif
 594   /* connect failed / timed out */
 595   GNUNET_break (h->ap_head == NULL);
 596   GNUNET_break (h->ap_tail == NULL);
 597   GNUNET_break (h->dns_active == GNUNET_NO);
 598   GNUNET_break (h->sock == NULL);
 599
 600   /* trigger jobs that used to wait on "connect_task" */
 601   if (0 != (h->ccs & COCO_RECEIVE_AGAIN))
 602     {
 603 #if DEBUG_CONNECTION
 604       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 605                   "connect_fail_continuation triggers receive_again (%p)\n",
 606                   h);
 607 #endif
 608       h->ccs -= COCO_RECEIVE_AGAIN;
 609       h->read_task = GNUNET_SCHEDULER_add_after (h->sched,
 610                                                  GNUNET_SCHEDULER_NO_TASK,
 611                                                  &receive_again, h);
 612     }
 613   if (0 != (h->ccs & COCO_TRANSMIT_READY))
 614     {
 615 #if DEBUG_CONNECTION
 616       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 617                   "connect_fail_continuation cancels timeout_task, triggers transmit_ready (%p)\n",
 618                   h);
 619 #endif
 620       GNUNET_assert (h->nth.timeout_task != GNUNET_SCHEDULER_NO_TASK);
 621       GNUNET_SCHEDULER_cancel (h->sched, h->nth.timeout_task);
 622       h->nth.timeout_task = GNUNET_SCHEDULER_NO_TASK;
 623       h->ccs -= COCO_TRANSMIT_READY;
 624       GNUNET_assert (h->write_task == GNUNET_SCHEDULER_NO_TASK);
 625       h->write_task = GNUNET_SCHEDULER_add_after (h->sched,
 626                                                   GNUNET_SCHEDULER_NO_TASK,
 627                                                   &transmit_ready, h);
 628     }
 629   if (0 != (h->ccs & COCO_DESTROY_CONTINUATION))
 630     {
 631 #if DEBUG_CONNECTION
 632       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 633                   "connect_fail_continuation runs destroy_continuation (%p)\n",
 634                   h);
 635 #endif
 636       h->ccs -= COCO_DESTROY_CONTINUATION;
 637       GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == h->destroy_task);
 638       h->destroy_task
 639         = GNUNET_SCHEDULER_add_now (h->sched,
 640                                     &destroy_continuation,
 641                                     h);
 642     }
 643 }
 644
 645
 646 /**
 647  * We've succeeded in establishing a connection.
 648  *
 649  * @param h the connection we tried to establish
 650  */
 651 static void
 652 connect_success_continuation (struct GNUNET_CONNECTION_Handle *h)
 653 {
 654 #if DEBUG_CONNECTION
 655   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 656               "Connection to `%s' succeeded! (%p)\n",
 657               GNUNET_a2s (h->addr, h->addrlen), h);
 658 #endif
 659   /* trigger jobs that waited for the connection */
 660   if (0 != (h->ccs & COCO_RECEIVE_AGAIN))
 661     {
 662 #if DEBUG_CONNECTION
 663       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 664                   "connect_success_continuation runs receive_again (%p)\n",
 665                   h);
 666 #endif
 667       h->ccs -= COCO_RECEIVE_AGAIN;
 668       h->read_task = GNUNET_SCHEDULER_add_after (h->sched,
 669                                                  GNUNET_SCHEDULER_NO_TASK,
 670                                                  &receive_again, h);
 671     }
 672   if (0 != (h->ccs & COCO_TRANSMIT_READY))
 673     {
 674 #if DEBUG_CONNECTION
 675       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 676                   "connect_success_continuation runs transmit_ready, cancels timeout_task (%p)\n",
 677                   h);
 678 #endif
 679       GNUNET_assert (h->nth.timeout_task != GNUNET_SCHEDULER_NO_TASK);
 680       GNUNET_SCHEDULER_cancel (h->sched, h->nth.timeout_task);
 681       h->nth.timeout_task = GNUNET_SCHEDULER_NO_TASK;
 682       h->ccs -= COCO_TRANSMIT_READY;
 683       GNUNET_assert (h->write_task == GNUNET_SCHEDULER_NO_TASK);
 684       h->write_task =
 685         GNUNET_SCHEDULER_add_write_net (h->sched,
 686                                         GNUNET_TIME_absolute_get_remaining
 687                                         (h->nth.transmit_timeout), h->sock,
 688                                         &transmit_ready, h);
 689     }
 690   if (0 != (h->ccs & COCO_DESTROY_CONTINUATION))
 691     {
 692 #if DEBUG_CONNECTION
 693       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 694                   "connect_success_continuation runs destroy_continuation (%p)\n",
 695                   h);
 696 #endif
 697       h->ccs -= COCO_DESTROY_CONTINUATION;
 698       GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == h->destroy_task);
 699       h->destroy_task
 700         = GNUNET_SCHEDULER_add_now (h->sched,
 701                                     &destroy_continuation,
 702                                     h);
 703     }
 704 }
 705
 706
 707 /**
 708  * Scheduler let us know that we're either ready to write on the
 709  * socket OR connect timed out.  Do the right thing.
 710  *
 711  * @param cls the "struct AddressProbe*" with the address that we are probing
 712  * @param tc success or failure info about the connect attempt.
 713  */
 714 static void
 715 connect_probe_continuation (void *cls,
 716                             const struct GNUNET_SCHEDULER_TaskContext *tc)
 717 {
 718   struct AddressProbe *ap = cls;
 719   struct GNUNET_CONNECTION_Handle *h = ap->h;
 720   struct AddressProbe *pos;
 721   int error;
 722   unsigned int len;
 723
 724   GNUNET_assert (ap->sock != NULL);
 725   GNUNET_CONTAINER_DLL_remove (h->ap_head, h->ap_tail, ap);
 726   len = sizeof (error);
 727   errno = 0;
 728   error = 0;
 729   if ( (0 == (tc->reason & GNUNET_SCHEDULER_REASON_WRITE_READY)) ||
 730        (GNUNET_OK !=
 731         GNUNET_NETWORK_socket_getsockopt (ap->sock, SOL_SOCKET, SO_ERROR,
 732                                           &error, &len)) ||
 733        (error != 0) )
 734     {
 735       GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (ap->sock));
 736       GNUNET_free (ap);
 737       if ((NULL == h->ap_head) && (h->dns_active == GNUNET_NO))
 738         connect_fail_continuation (h);
 739       return;
 740     }
 741   GNUNET_assert (h->sock == NULL);
 742   h->sock = ap->sock;
 743   GNUNET_assert (h->addr == NULL);
 744   h->addr = GNUNET_malloc (ap->addrlen);
 745   memcpy (h->addr, ap->addr, ap->addrlen);
 746   h->addrlen = ap->addrlen;
 747   GNUNET_free (ap);
 748   /* cancel all other attempts */
 749   while (NULL != (pos = h->ap_head))
 750     {
 751       GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (pos->sock));
 752       GNUNET_SCHEDULER_cancel (h->sched, pos->task);
 753       GNUNET_CONTAINER_DLL_remove (h->ap_head, h->ap_tail, pos);
 754       GNUNET_free (pos);
 755     }
 756   connect_success_continuation (h);
 757 }
 758
 759
 760 /**
 761  * Try to establish a socket connection given the specified address.
 762  * This function is called by the resolver once we have a DNS reply.
 763  *
 764  * @param cls our "struct GNUNET_CONNECTION_Handle *"
 765  * @param addr address to try, NULL for "last call"
 766  * @param addrlen length of addr
 767  */
 768 static void
 769 try_connect_using_address (void *cls,
 770                            const struct sockaddr *addr, socklen_t addrlen)
 771 {
 772   struct GNUNET_CONNECTION_Handle *h = cls;
 773   struct AddressProbe *ap;
 774   struct GNUNET_TIME_Relative delay;
 775
 776   if (addr == NULL)
 777     {
 778       h->dns_active = NULL;
 779       if (NULL == h->ap_head)
 780         connect_fail_continuation (h);
 781       return;
 782     }
 783   if (h->sock != NULL)
 784     return;                     /* already connected */
 785   GNUNET_assert (h->addr == NULL);
 786   /* try to connect */
 787 #if DEBUG_CONNECTION
 788   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 789               "Trying to connect using address `%s:%u/%s:%u'\n",
 790               h->hostname, h->port, GNUNET_a2s (addr, addrlen), h->port);
 791 #endif
 792   ap = GNUNET_malloc (sizeof (struct AddressProbe) + addrlen);
 793   ap->addr = (const struct sockaddr *) &ap[1];
 794   memcpy (&ap[1], addr, addrlen);
 795   ap->addrlen = addrlen;
 796   ap->h = h;
 797
 798   switch (ap->addr->sa_family)
 799     {
 800     case AF_INET:
 801       ((struct sockaddr_in *) ap->addr)->sin_port = htons (h->port);
 802       break;
 803     case AF_INET6:
 804       ((struct sockaddr_in6 *) ap->addr)->sin6_port = htons (h->port);
 805       break;
 806     default:
 807       GNUNET_break (0);
 808       GNUNET_free (ap);
 809       return;                   /* not supported by us */
 810     }
 811   ap->sock =
 812     GNUNET_NETWORK_socket_create (ap->addr->sa_family, SOCK_STREAM, 0);
 813   if (ap->sock == NULL)
 814     {
 815       GNUNET_free (ap);
 816       return;                   /* not supported by OS */
 817     }
 818 #if DEBUG_CONNECTION
 819   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 820               _("Trying to connect to `%s' (%p)\n"),
 821               GNUNET_a2s (ap->addr, ap->addrlen), h);
 822 #endif
 823   if ((GNUNET_OK != GNUNET_NETWORK_socket_connect (ap->sock,
 824                                                    ap->addr,
 825                                                    ap->addrlen)) &&
 826       (errno != EINPROGRESS))
 827     {
 828       /* maybe refused / unsupported address, try next */
 829       GNUNET_log_strerror (GNUNET_ERROR_TYPE_INFO, "connect");
 830       GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (ap->sock));
 831       GNUNET_free (ap);
 832       return;
 833     }
 834   GNUNET_CONTAINER_DLL_insert (h->ap_head, h->ap_tail, ap);
 835   delay = GNUNET_CONNECTION_CONNECT_RETRY_TIMEOUT;
 836   if (h->nth.notify_ready != NULL)
 837     delay = GNUNET_TIME_relative_min (delay,
 838                                       GNUNET_TIME_absolute_get_remaining
 839                                       (h->nth.transmit_timeout));
 840   if (h->receiver != NULL)
 841     delay = GNUNET_TIME_relative_min (delay,
 842                                       GNUNET_TIME_absolute_get_remaining
 843                                       (h->receive_timeout));
 844   ap->task =
 845     GNUNET_SCHEDULER_add_write_net (h->sched, delay, ap->sock,
 846                                     &connect_probe_continuation, ap);
 847 }
 848
 849
 850 /**
 851  * Create a socket handle by (asynchronously) connecting to a host.
 852  * This function returns immediately, even if the connection has not
 853  * yet been established.  This function only creates TCP connections.
 854  *
 855  * @param sched scheduler to use
 856  * @param cfg configuration to use
 857  * @param hostname name of the host to connect to
 858  * @param port port to connect to
 859  * @return the socket handle
 860  */
 861 struct GNUNET_CONNECTION_Handle *
 862 GNUNET_CONNECTION_create_from_connect (struct GNUNET_SCHEDULER_Handle *sched,
 863                                        const struct
 864                                        GNUNET_CONFIGURATION_Handle *cfg,
 865                                        const char *hostname, uint16_t port)
 866 {
 867   struct GNUNET_CONNECTION_Handle *ret;
 868
 869   GNUNET_assert (0 < strlen (hostname));        /* sanity check */
 870   ret = GNUNET_malloc (sizeof (struct GNUNET_CONNECTION_Handle));
 871   ret->cfg = cfg;
 872   ret->sched = sched;
 873   ret->write_buffer_size = GNUNET_SERVER_MIN_BUFFER_SIZE;
 874   ret->write_buffer = GNUNET_malloc(ret->write_buffer_size);
 875   ret->port = port;
 876   ret->hostname = GNUNET_strdup (hostname);
 877   ret->dns_active = GNUNET_RESOLVER_ip_get (sched,
 878                                             cfg,
 879                                             ret->hostname,
 880                                             AF_UNSPEC,
 881                                             GNUNET_CONNECTION_CONNECT_RETRY_TIMEOUT,
 882                                             &try_connect_using_address, ret);
 883   return ret;
 884 }
 885
 886
 887 /**
 888  * Create a socket handle by connecting to a UNIX domain service.
 889  * This function returns immediately, even if the connection has not
 890  * yet been established.  This function only creates UNIX connections.
 891  *
 892  * @param sched scheduler to use
 893  * @param cfg configuration to use
 894  * @param unixpath path to connect to
 895  * @return the socket handle, NULL on systems without UNIX support
 896  */
 897 struct GNUNET_CONNECTION_Handle *
 898 GNUNET_CONNECTION_create_from_connect_to_unixpath (struct GNUNET_SCHEDULER_Handle *sched,
 899                                                    const struct
 900                                                    GNUNET_CONFIGURATION_Handle *cfg,
 901                                                    const char *unixpath)
 902 {
 903 #ifdef AF_UNIX
 904   struct GNUNET_CONNECTION_Handle *ret;
 905   struct sockaddr_un *un;
 906   size_t slen;
 907
 908   GNUNET_assert (0 < strlen (unixpath));        /* sanity check */
 909   un = GNUNET_malloc (sizeof (struct sockaddr_un));
 910   un->sun_family = AF_UNIX;
 911   slen = strlen (unixpath) + 1;
 912   if (slen >= sizeof (un->sun_path))
 913     slen = sizeof (un->sun_path) - 1;
 914   memcpy (un->sun_path,
 915           unixpath,
 916           slen);
 917   un->sun_path[slen] = '\0';
 918   slen += sizeof (sa_family_t);
 919 #if LINUX
 920   un->sun_path[0] = '\0';
 921   slen = sizeof (struct sockaddr_un);
 922 #endif
 923   ret = GNUNET_malloc (sizeof (struct GNUNET_CONNECTION_Handle));
 924   ret->cfg = cfg;
 925   ret->sched = sched;
 926   ret->write_buffer_size = GNUNET_SERVER_MIN_BUFFER_SIZE;
 927   ret->write_buffer = GNUNET_malloc(ret->write_buffer_size);
 928   ret->port = 0;
 929   ret->hostname = NULL;
 930   ret->addr = (struct sockaddr*) un;
 931   ret->addrlen = slen;
 932   ret->sock = GNUNET_NETWORK_socket_create (AF_UNIX, SOCK_STREAM, 0);
 933   if (NULL == ret->sock)
 934     {
 935       GNUNET_free (ret->addr);
 936       GNUNET_free (ret->write_buffer);
 937       GNUNET_free (ret);
 938       return NULL;
 939     }
 940   if (GNUNET_OK != GNUNET_NETWORK_socket_connect (ret->sock,
 941                                                   ret->addr,
 942                                                   ret->addrlen))
 943     {
 944       GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (ret->sock));
 945       GNUNET_free (ret->addr);
 946       GNUNET_free (ret->write_buffer);
 947       GNUNET_free (ret);
 948       return NULL;
 949     }
 950   connect_success_continuation (ret);
 951   return ret;
 952 #else
 953   return NULL;
 954 #endif
 955 }
 956
 957
 958 /**
 959  * Create a socket handle by (asynchronously) connecting to a host.
 960  * This function returns immediately, even if the connection has not
 961  * yet been established.  This function only creates TCP connections.
 962  *
 963  * @param sched scheduler to use
 964  * @param af_family address family to use
 965  * @param serv_addr server address
 966  * @param addrlen length of server address
 967  * @return the socket handle
 968  */
 969 struct GNUNET_CONNECTION_Handle *
 970 GNUNET_CONNECTION_create_from_sockaddr (struct GNUNET_SCHEDULER_Handle
 971                                         *sched, int af_family,
 972                                         const struct sockaddr *serv_addr,
 973                                         socklen_t addrlen)
 974 {
 975   struct GNUNET_NETWORK_Handle *s;
 976   struct GNUNET_CONNECTION_Handle *ret;
 977
 978   s = GNUNET_NETWORK_socket_create (af_family, SOCK_STREAM, 0);
 979   if (s == NULL)
 980     {
 981       GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING |
 982                            GNUNET_ERROR_TYPE_BULK, "socket");
 983       return NULL;
 984     }
 985   if ((GNUNET_OK != GNUNET_NETWORK_socket_connect (s, serv_addr, addrlen))
 986       && (errno != EINPROGRESS))
 987     {
 988       /* maybe refused / unsupported address, try next */
 989       GNUNET_log_strerror (GNUNET_ERROR_TYPE_INFO, "connect");
 990       GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (s));
 991       return NULL;
 992     }
 993   ret = GNUNET_CONNECTION_create_from_existing (sched, s);
 994   ret->addr = GNUNET_malloc (addrlen);
 995   memcpy (ret->addr, serv_addr, addrlen);
 996   ret->addrlen = addrlen;
 997 #if DEBUG_CONNECTION
 998   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
 999               _("Trying to connect to `%s' (%p)\n"),
1000               GNUNET_a2s (serv_addr, addrlen), ret);
1001 #endif
1002   return ret;
1003 }
1004
1005
1006 /**
1007  * Check if socket is valid (no fatal errors have happened so far).
1008  * Note that a socket that is still trying to connect is considered
1009  * valid.
1010  *
1011  * @param sock socket to check
1012  * @return GNUNET_YES if valid, GNUNET_NO otherwise
1013  */
1014 int
1015 GNUNET_CONNECTION_check (struct GNUNET_CONNECTION_Handle *sock)
1016 {
1017   if ((sock->ap_head != NULL) || (sock->dns_active != NULL))
1018     return GNUNET_YES;          /* still trying to connect */
1019   return (sock->sock == NULL) ? GNUNET_NO : GNUNET_YES;
1020 }
1021
1022
1023 /**
1024  * Close the socket and free associated resources. Pending
1025  * transmissions may be completed or dropped depending on the
1026  * arguments.   If a receive call is pending and should
1027  * NOT be completed, 'GNUNET_CONNECTION_receive_cancel'
1028  * should be called explicitly first.
1029  *
1030  * @param sock socket to destroy
1031  * @param finish_pending_write should pending writes be completed or aborted?
1032  *        (this applies to transmissions where the data has already been
1033  *        read from the application; all other transmissions should be
1034  *        aborted using 'GNUNET_CONNECTION_notify_transmit_ready_cancel').
1035  */
1036 void
1037 GNUNET_CONNECTION_destroy (struct GNUNET_CONNECTION_Handle *sock,
1038                            int finish_pending_write)
1039 {
1040   if (GNUNET_NO == finish_pending_write)
1041     {
1042       if (sock->write_task != GNUNET_SCHEDULER_NO_TASK)
1043         {
1044           GNUNET_SCHEDULER_cancel (sock->sched,
1045                                    sock->write_task);
1046           sock->write_task = GNUNET_SCHEDULER_NO_TASK;
1047           sock->write_buffer_off = 0;
1048         }
1049     }
1050   if ((sock->write_buffer_off == 0) && (sock->dns_active != NULL))
1051     {
1052       GNUNET_RESOLVER_request_cancel (sock->dns_active);
1053       sock->dns_active = NULL;
1054     }
1055   GNUNET_assert (sock->sched != NULL);
1056   GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == sock->destroy_task);
1057   sock->destroy_task
1058     = GNUNET_SCHEDULER_add_now (sock->sched,
1059                                 &destroy_continuation, sock);
1060 }
1061
1062
1063 /**
1064  * Tell the receiver callback that a timeout was reached.
1065  */
1066 static void
1067 signal_timeout (struct GNUNET_CONNECTION_Handle *sh)
1068 {
1069   GNUNET_CONNECTION_Receiver receiver;
1070
1071 #if DEBUG_CONNECTION
1072   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1073               "Network signals time out to receiver (%p)!\n", sh);
1074 #endif
1075   GNUNET_assert (NULL != (receiver = sh->receiver));
1076   sh->receiver = NULL;
1077   receiver (sh->receiver_cls, NULL, 0, NULL, 0, 0);
1078 }
1079
1080
1081 /**
1082  * Tell the receiver callback that we had an IO error.
1083  */
1084 static void
1085 signal_error (struct GNUNET_CONNECTION_Handle *sh, int errcode)
1086 {
1087   GNUNET_CONNECTION_Receiver receiver;
1088   GNUNET_assert (NULL != (receiver = sh->receiver));
1089   sh->receiver = NULL;
1090   receiver (sh->receiver_cls, NULL, 0, sh->addr, sh->addrlen, errcode);
1091 }
1092
1093
1094 /**
1095  * This function is called once we either timeout
1096  * or have data ready to read.
1097  */
1098 static void
1099 receive_ready (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1100 {
1101   struct GNUNET_CONNECTION_Handle *sh = cls;
1102   struct GNUNET_TIME_Absolute now;
1103   char buffer[sh->max];
1104   ssize_t ret;
1105   GNUNET_CONNECTION_Receiver receiver;
1106
1107   sh->read_task = GNUNET_SCHEDULER_NO_TASK;
1108   if ( (GNUNET_YES == sh->ignore_shutdown) &&
1109        (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)))
1110     {
1111       /* ignore shutdown request, go again immediately */
1112 #if DEBUG_CONNECTION
1113       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1114                   "Ignoring shutdown signal per configuration\n");
1115 #endif
1116       sh->read_task = GNUNET_SCHEDULER_add_read_net (tc->sched,
1117                                                      GNUNET_TIME_absolute_get_remaining
1118                                                      (sh->receive_timeout),
1119                                                      sh->sock,
1120                                                      &receive_ready, sh);
1121       return;
1122     }
1123   now = GNUNET_TIME_absolute_get ();
1124   if ((now.value > sh->receive_timeout.value) ||
1125       (0 != (tc->reason & GNUNET_SCHEDULER_REASON_TIMEOUT)) ||
1126       (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)))
1127     {
1128 #if DEBUG_CONNECTION
1129       if (0 == (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
1130         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1131                     "Receive from `%s' encounters error: time out by %llums... (%p)\n",
1132                     GNUNET_a2s (sh->addr, sh->addrlen),
1133                     GNUNET_TIME_absolute_get_duration (sh->receive_timeout).
1134                     value, sh);
1135 #endif
1136       signal_timeout (sh);
1137       return;
1138     }
1139   if (sh->sock == NULL)
1140     {
1141       /* connect failed for good */
1142 #if DEBUG_CONNECTION
1143       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1144                   "Receive encounters error, socket closed... (%p)\n", sh);
1145 #endif
1146       signal_error (sh, ECONNREFUSED);
1147       return;
1148     }
1149   GNUNET_assert (GNUNET_NETWORK_fdset_isset (tc->read_ready, sh->sock));
1150 RETRY:
1151   ret = GNUNET_NETWORK_socket_recv (sh->sock, buffer, sh->max);
1152   if (ret == -1)
1153     {
1154       if (errno == EINTR)
1155         goto RETRY;
1156 #if DEBUG_CONNECTION
1157       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1158                   "Error receiving: %s\n", STRERROR (errno));
1159 #endif
1160       signal_error (sh, errno);
1161       return;
1162     }
1163 #if DEBUG_CONNECTION
1164   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1165               "receive_ready read %u/%u bytes from `%s' (%p)!\n",
1166               (unsigned int) ret,
1167               sh->max, GNUNET_a2s (sh->addr, sh->addrlen), sh);
1168 #endif
1169   GNUNET_assert (NULL != (receiver = sh->receiver));
1170   sh->receiver = NULL;
1171   receiver (sh->receiver_cls, buffer, ret, sh->addr, sh->addrlen, 0);
1172 }
1173
1174
1175 /**
1176  * This function is called after establishing a connection either has
1177  * succeeded or timed out.  Note that it is possible that the attempt
1178  * timed out and that we're immediately retrying.  If we are retrying,
1179  * we need to wait again (or timeout); if we succeeded, we need to
1180  * wait for data (or timeout).
1181  *
1182  * @param cls our connection handle
1183  * @param tc task context describing why we are here
1184  */
1185 static void
1186 receive_again (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1187 {
1188   struct GNUNET_CONNECTION_Handle *sh = cls;
1189   struct GNUNET_TIME_Absolute now;
1190
1191   sh->read_task = GNUNET_SCHEDULER_NO_TASK;
1192   if (sh->sock == NULL)
1193     {
1194       /* not connected and no longer trying */
1195 #if DEBUG_CONNECTION
1196       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1197                   "Receive encounters error, socket closed (%p)...\n", sh);
1198 #endif
1199       signal_error (sh, ECONNREFUSED);
1200       return;
1201     }
1202   now = GNUNET_TIME_absolute_get ();
1203   if ((now.value > sh->receive_timeout.value) ||
1204       (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)))
1205     {
1206 #if DEBUG_CONNECTION
1207       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1208                   "Receive encounters error: time out (%p)...\n", sh);
1209 #endif
1210       signal_timeout (sh);
1211       return;
1212     }
1213   GNUNET_assert (sh->sock != NULL);
1214   /* connect succeeded, wait for data! */
1215   sh->read_task = GNUNET_SCHEDULER_add_read_net (tc->sched,
1216                                                  GNUNET_TIME_absolute_get_remaining
1217                                                  (sh->receive_timeout),
1218                                                  sh->sock,
1219                                                  &receive_ready, sh);
1220 }
1221
1222
1223 /**
1224  * Receive data from the given socket.  Note that this function will
1225  * call "receiver" asynchronously using the scheduler.  It will
1226  * "immediately" return.  Note that there MUST only be one active
1227  * receive call per socket at any given point in time (so do not
1228  * call receive again until the receiver callback has been invoked).
1229  *
1230  * @param sock socket handle
1231  * @param max maximum number of bytes to read
1232  * @param timeout maximum amount of time to wait (use -1 for "forever")
1233  * @param receiver function to call with received data
1234  * @param receiver_cls closure for receiver
1235  */
1236 void
1237 GNUNET_CONNECTION_receive (struct GNUNET_CONNECTION_Handle *sock,
1238                            size_t max,
1239                            struct GNUNET_TIME_Relative timeout,
1240                            GNUNET_CONNECTION_Receiver receiver,
1241                            void *receiver_cls)
1242 {
1243   struct GNUNET_SCHEDULER_TaskContext tc;
1244
1245   GNUNET_assert ((sock->read_task == GNUNET_SCHEDULER_NO_TASK) &&
1246                  (0 == (sock->ccs & COCO_RECEIVE_AGAIN)) &&
1247                  (sock->receiver == NULL));
1248   sock->receiver = receiver;
1249   sock->receiver_cls = receiver_cls;
1250   sock->receive_timeout = GNUNET_TIME_relative_to_absolute (timeout);
1251   sock->max = max;
1252   if (sock->sock != NULL)
1253     {
1254       memset (&tc, 0, sizeof (tc));
1255       tc.sched = sock->sched;
1256       tc.reason = GNUNET_SCHEDULER_REASON_PREREQ_DONE;
1257       receive_again (sock, &tc);
1258       return;
1259     }
1260   if ((sock->dns_active == NULL) && (sock->ap_head == NULL))
1261     {
1262       receiver (receiver_cls, NULL, 0, NULL, 0, ETIMEDOUT);
1263       return;
1264     }
1265   sock->ccs += COCO_RECEIVE_AGAIN;
1266 }
1267
1268
1269 /**
1270  * Configure this connection to ignore shutdown signals.
1271  *
1272  * @param sock socket handle
1273  * @param do_ignore GNUNET_YES to ignore, GNUNET_NO to restore default
1274  */
1275 void
1276 GNUNET_CONNECTION_ignore_shutdown (struct GNUNET_CONNECTION_Handle *sock,
1277                                    int do_ignore)
1278 {
1279   sock->ignore_shutdown = do_ignore;
1280 }
1281
1282
1283 /**
1284  * Cancel receive job on the given socket.  Note that the
1285  * receiver callback must not have been called yet in order
1286  * for the cancellation to be valid.
1287  *
1288  * @param sock socket handle
1289  * @return closure of the original receiver callback closure
1290  */
1291 void *
1292 GNUNET_CONNECTION_receive_cancel (struct GNUNET_CONNECTION_Handle *sock)
1293 {
1294   if (sock->read_task != GNUNET_SCHEDULER_NO_TASK)
1295     {
1296       GNUNET_assert (sock == GNUNET_SCHEDULER_cancel (sock->sched,
1297                                                       sock->read_task));
1298       sock->read_task = GNUNET_SCHEDULER_NO_TASK;
1299     }
1300   else
1301     {
1302       GNUNET_assert (0 != (sock->ccs & COCO_RECEIVE_AGAIN));
1303       sock->ccs -= COCO_RECEIVE_AGAIN;
1304     }
1305   sock->receiver = NULL;
1306   return sock->receiver_cls;
1307 }
1308
1309
1310 /**
1311  * Try to call the transmit notify method (check if we do
1312  * have enough space available first)!
1313  *
1314  * @param sock socket for which we should do this processing
1315  * @return GNUNET_YES if we were able to call notify
1316  */
1317 static int
1318 process_notify (struct GNUNET_CONNECTION_Handle *sock)
1319 {
1320   size_t used;
1321   size_t avail;
1322   size_t size;
1323   GNUNET_CONNECTION_TransmitReadyNotify notify;
1324
1325   GNUNET_assert (sock->write_task == GNUNET_SCHEDULER_NO_TASK);
1326   if (NULL == (notify = sock->nth.notify_ready))
1327     return GNUNET_NO;
1328   used = sock->write_buffer_off - sock->write_buffer_pos;
1329   avail = sock->write_buffer_size - used;
1330   size = sock->nth.notify_size;
1331   if (size > avail)
1332     return GNUNET_NO;
1333   sock->nth.notify_ready = NULL;
1334   if (sock->write_buffer_size - sock->write_buffer_off < size)
1335     {
1336       /* need to compact */
1337       memmove (sock->write_buffer,
1338                &sock->write_buffer[sock->write_buffer_pos], used);
1339       sock->write_buffer_off -= sock->write_buffer_pos;
1340       sock->write_buffer_pos = 0;
1341     }
1342   avail = sock->write_buffer_size - sock->write_buffer_off;
1343   GNUNET_assert (avail >= size);
1344   size = notify (sock->nth.notify_ready_cls,
1345                  avail,
1346                  &sock->write_buffer[sock->write_buffer_off]);
1347   GNUNET_assert (size <= avail);
1348   sock->write_buffer_off += size;
1349   return GNUNET_YES;
1350 }
1351
1352
1353 /**
1354  * Task invoked by the scheduler when a call to transmit
1355  * is timing out (we never got enough buffer space to call
1356  * the callback function before the specified timeout
1357  * expired).
1358  *
1359  * This task notifies the client about the timeout.
1360  */
1361 static void
1362 transmit_timeout (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1363 {
1364   struct GNUNET_CONNECTION_Handle *sock = cls;
1365   GNUNET_CONNECTION_TransmitReadyNotify notify;
1366
1367 #if DEBUG_CONNECTION
1368   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1369               "transmit_timeout running (%p)\n", sock);
1370 #endif
1371   sock->nth.timeout_task = GNUNET_SCHEDULER_NO_TASK;
1372 #if DEBUG_CONNECTION
1373   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1374               "Transmit to `%s:%u/%s' fails, time out reached (%p).\n",
1375               sock->hostname,
1376               sock->port, GNUNET_a2s (sock->addr, sock->addrlen), sock);
1377 #endif
1378   GNUNET_assert (0 != (sock->ccs & COCO_TRANSMIT_READY));
1379   sock->ccs -= COCO_TRANSMIT_READY;     /* remove request */
1380   notify = sock->nth.notify_ready;
1381   sock->nth.notify_ready = NULL;
1382   notify (sock->nth.notify_ready_cls, 0, NULL);
1383 }
1384
1385
1386 /**
1387  * Task invoked by the scheduler when we failed to connect
1388  * at the time of being asked to transmit.
1389  *
1390  * This task notifies the client about the error.
1391  */
1392 static void
1393 connect_error (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1394 {
1395   struct GNUNET_CONNECTION_Handle *sock = cls;
1396   GNUNET_CONNECTION_TransmitReadyNotify notify;
1397
1398 #if DEBUG_CONNECTION
1399   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1400               "Transmission request of size %u fails, connection failed (%p).\n",
1401               sock->nth.notify_size, sock);
1402 #endif
1403   sock->write_task = GNUNET_SCHEDULER_NO_TASK;
1404   notify = sock->nth.notify_ready;
1405   sock->nth.notify_ready = NULL;
1406   notify (sock->nth.notify_ready_cls, 0, NULL);
1407 }
1408
1409
1410 static void
1411 transmit_error (struct GNUNET_CONNECTION_Handle *sock)
1412 {
1413   GNUNET_CONNECTION_TransmitReadyNotify notify;
1414
1415   if (NULL != sock->sock)
1416     {
1417       GNUNET_NETWORK_socket_shutdown (sock->sock, SHUT_RDWR);
1418       GNUNET_break (GNUNET_OK ==
1419                     GNUNET_NETWORK_socket_close (sock->sock));
1420       sock->sock = NULL;
1421     }
1422   if (sock->read_task != GNUNET_SCHEDULER_NO_TASK)
1423     {
1424       GNUNET_SCHEDULER_cancel (sock->sched,
1425                                sock->read_task);
1426       sock->read_task = GNUNET_SCHEDULER_NO_TASK;
1427       signal_timeout (sock);
1428       return;
1429     }
1430   if (sock->nth.notify_ready == NULL)
1431     return;                     /* nobody to tell about it */
1432   notify = sock->nth.notify_ready;
1433   sock->nth.notify_ready = NULL;
1434   notify (sock->nth.notify_ready_cls, 0, NULL);
1435 }
1436
1437
1438 /**
1439  * See if we are now connected.  If not, wait longer for
1440  * connect to succeed.  If connected, we should be able
1441  * to write now as well, unless we timed out.
1442  *
1443  * @param cls our connection handle
1444  * @param tc task context describing why we are here
1445  */
1446 static void
1447 transmit_ready (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1448 {
1449   struct GNUNET_CONNECTION_Handle *sock = cls;
1450   GNUNET_CONNECTION_TransmitReadyNotify notify;
1451   ssize_t ret;
1452   size_t have;
1453
1454 #if DEBUG_CONNECTION
1455   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1456               "transmit_ready running (%p).\n", sock);
1457 #endif
1458   GNUNET_assert (sock->write_task != GNUNET_SCHEDULER_NO_TASK);
1459   sock->write_task = GNUNET_SCHEDULER_NO_TASK;
1460   GNUNET_assert (sock->nth.timeout_task == GNUNET_SCHEDULER_NO_TASK);
1461   if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
1462     {
1463       if (sock->ignore_shutdown == GNUNET_YES)
1464         goto SCHEDULE_WRITE;    /* ignore shutdown, go again immediately */
1465 #if DEBUG_CONNECTION
1466       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1467                   "Transmit to `%s' fails, shutdown happened (%p).\n",
1468                   GNUNET_a2s (sock->addr, sock->addrlen), sock);
1469 #endif
1470       notify = sock->nth.notify_ready;
1471       sock->nth.notify_ready = NULL;
1472       notify (sock->nth.notify_ready_cls, 0, NULL);
1473       return;
1474     }
1475   if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_TIMEOUT))
1476     {
1477 #if DEBUG_CONNECTION
1478       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1479                   "Transmit to `%s' fails, time out reached (%p).\n",
1480                   GNUNET_a2s (sock->addr, sock->addrlen), sock);
1481 #endif
1482       notify = sock->nth.notify_ready;
1483       sock->nth.notify_ready = NULL;
1484       notify (sock->nth.notify_ready_cls, 0, NULL);
1485       return;
1486     }
1487   GNUNET_assert (NULL != sock->sock);
1488   if (tc->write_ready == NULL)
1489     {
1490       /* special circumstances (in particular,
1491          PREREQ_DONE after connect): not yet ready to write,
1492          but no "fatal" error either.  Hence retry.  */
1493       goto SCHEDULE_WRITE;
1494     }
1495   if (!GNUNET_NETWORK_fdset_isset (tc->write_ready, sock->sock))
1496     {
1497 #if DEBUG_CONNECTION
1498       GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1499                   _
1500                   ("Could not satisfy pending transmission request, socket closed or connect failed (%p).\n"),
1501                   sock);
1502 #endif
1503       transmit_error (sock);
1504       return;                   /* connect failed for good, we're finished */
1505     }
1506   GNUNET_assert (sock->write_buffer_off >= sock->write_buffer_pos);
1507   if ( (sock->nth.notify_ready != NULL) &&
1508        (sock->write_buffer_size < sock->nth.notify_size) )
1509     {
1510       sock->write_buffer = GNUNET_realloc(sock->write_buffer,
1511                                           sock->nth.notify_size);
1512       sock->write_buffer_size = sock->nth.notify_size;
1513     }
1514   process_notify (sock);
1515   have = sock->write_buffer_off - sock->write_buffer_pos;
1516   if (have == 0)
1517     {
1518       /* no data ready for writing, terminate write loop */
1519       return;
1520     }
1521   GNUNET_assert (have <= sock->write_buffer_size);
1522   GNUNET_assert (have + sock->write_buffer_pos <= sock->write_buffer_size);
1523   GNUNET_assert (sock->write_buffer_pos <= sock->write_buffer_size);
1524 RETRY:
1525   ret = GNUNET_NETWORK_socket_send (sock->sock,
1526                                     &sock->write_buffer[sock->
1527                                                         write_buffer_pos],
1528                                     have);
1529   if (ret == -1)
1530     {
1531       if (errno == EINTR)
1532         goto RETRY;
1533 #if 0
1534       int en = errno;
1535       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1536                   _("Failed to send to `%s': %s\n"),
1537                   GNUNET_a2s (sock->addr,
1538                               sock->addrlen),
1539                   STRERROR (en));
1540 #endif
1541 #if DEBUG_CONNECTION
1542       GNUNET_log_strerror (GNUNET_ERROR_TYPE_DEBUG, "send");
1543 #endif
1544       transmit_error (sock);
1545       return;
1546     }
1547 #if DEBUG_CONNECTION
1548   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1549               "transmit_ready transmitted %u/%u bytes to `%s' (%p)\n",
1550               (unsigned int) ret,
1551               have, GNUNET_a2s (sock->addr, sock->addrlen), sock);
1552 #endif
1553   sock->write_buffer_pos += ret;
1554   if (sock->write_buffer_pos == sock->write_buffer_off)
1555     {
1556       /* transmitted all pending data */
1557       sock->write_buffer_pos = 0;
1558       sock->write_buffer_off = 0;
1559     }
1560   if ((sock->write_buffer_off == 0) && (NULL == sock->nth.notify_ready))
1561     return;                     /* all data sent! */
1562   /* not done writing, schedule more */
1563 SCHEDULE_WRITE:
1564 #if DEBUG_CONNECTION
1565   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1566               "Re-scheduling transmit_ready (more to do) (%p).\n", sock);
1567 #endif
1568   if (sock->write_task == GNUNET_SCHEDULER_NO_TASK)
1569     sock->write_task =
1570       GNUNET_SCHEDULER_add_write_net (tc->sched,
1571                                       GNUNET_TIME_absolute_get_remaining
1572                                       (sock->nth.transmit_timeout),
1573                                       sock->sock, &transmit_ready, sock);
1574 }
1575
1576
1577 /**
1578  * Ask the socket to call us once the specified number of bytes
1579  * are free in the transmission buffer.  May call the notify
1580  * method immediately if enough space is available.
1581  *
1582  * @param sock socket
1583  * @param size number of bytes to send
1584  * @param timeout after how long should we give up (and call
1585  *        notify with buf NULL and size 0)?
1586  * @param notify function to call
1587  * @param notify_cls closure for notify
1588  * @return non-NULL if the notify callback was queued,
1589  *         NULL if we are already going to notify someone else (busy)
1590  */
1591 struct GNUNET_CONNECTION_TransmitHandle *
1592 GNUNET_CONNECTION_notify_transmit_ready (struct GNUNET_CONNECTION_Handle
1593                                          *sock, size_t size,
1594                                          struct GNUNET_TIME_Relative timeout,
1595                                          GNUNET_CONNECTION_TransmitReadyNotify
1596                                          notify, void *notify_cls)
1597 {
1598   if (sock->nth.notify_ready != NULL)
1599     return NULL;
1600   GNUNET_assert (notify != NULL);
1601   GNUNET_assert (size < GNUNET_SERVER_MAX_MESSAGE_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 */