src/transport/tcp_connection_legacy.c

   1 /*
   2      This file is part of GNUnet.
   3      Copyright (C) 2009-2013 GNUnet e.V.
   4
   5      GNUnet is free software: you can redistribute it and/or modify it
   6      under the terms of the GNU Affero General Public License as published
   7      by the Free Software Foundation, either version 3 of the License,
   8      or (at your 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      Affero General Public License for more details.
  14
  15      You should have received a copy of the GNU Affero General Public License
  16      along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19 /**
  20  * @file util/connection.c
  21  * @brief  TCP connection management
  22  * @author Christian Grothoff
  23  *
  24  * This code is rather complex.  Only modify it if you
  25  * 1) Have a NEW testcase showing that the new code
  26  *    is needed and correct
  27  * 2) All EXISTING testcases pass with the new code
  28  * These rules should apply in general, but for this
  29  * module they are VERY, VERY important.
  30  */
  31 #include "platform.h"
  32 #include "gnunet_util_lib.h"
  33 #include "gnunet_resolver_service.h"
  34
  35
  36 /**
  37  * Timeout we use on TCP connect before trying another
  38  * result from the DNS resolver.  Actual value used
  39  * is this value divided by the number of address families.
  40  * Default is 5s.
  41  */
  42 #define CONNECT_RETRY_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5)
  43
  44
  45
  46 #define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "util-connection", syscall)
  47
  48
  49 /**
  50  * Transmission handle.  There can only be one for each connection.
  51  */
  52 struct GNUNET_CONNECTION_TransmitHandle
  53 {
  54
  55   /**
  56    * Function to call if the send buffer has notify_size
  57    * bytes available.
  58    */
  59   GNUNET_CONNECTION_TransmitReadyNotify notify_ready;
  60
  61   /**
  62    * Closure for notify_ready.
  63    */
  64   void *notify_ready_cls;
  65
  66   /**
  67    * Our connection handle.
  68    */
  69   struct GNUNET_CONNECTION_Handle *connection;
  70
  71   /**
  72    * Timeout for receiving (in absolute time).
  73    */
  74   struct GNUNET_TIME_Absolute transmit_timeout;
  75
  76   /**
  77    * Task called on timeout.
  78    */
  79   struct GNUNET_SCHEDULER_Task * timeout_task;
  80
  81   /**
  82    * At what number of bytes available in the
  83    * write buffer should the notify method be called?
  84    */
  85   size_t notify_size;
  86
  87 };
  88
  89
  90 /**
  91  * During connect, we try multiple possible IP addresses
  92  * to find out which one might work.
  93  */
  94 struct AddressProbe
  95 {
  96
  97   /**
  98    * This is a linked list.
  99    */
 100   struct AddressProbe *next;
 101
 102   /**
 103    * This is a doubly-linked list.
 104    */
 105   struct AddressProbe *prev;
 106
 107   /**
 108    * The address; do not free (allocated at the end of this struct).
 109    */
 110   const struct sockaddr *addr;
 111
 112   /**
 113    * Underlying OS's socket.
 114    */
 115   struct GNUNET_NETWORK_Handle *sock;
 116
 117   /**
 118    * Connection for which we are probing.
 119    */
 120   struct GNUNET_CONNECTION_Handle *connection;
 121
 122   /**
 123    * Lenth of addr.
 124    */
 125   socklen_t addrlen;
 126
 127   /**
 128    * Task waiting for the connection to finish connecting.
 129    */
 130   struct GNUNET_SCHEDULER_Task * task;
 131 };
 132
 133
 134 /**
 135  * @brief handle for a network connection
 136  */
 137 struct GNUNET_CONNECTION_Handle
 138 {
 139
 140   /**
 141    * Configuration to use.
 142    */
 143   const struct GNUNET_CONFIGURATION_Handle *cfg;
 144
 145   /**
 146    * Linked list of sockets we are currently trying out
 147    * (during connect).
 148    */
 149   struct AddressProbe *ap_head;
 150
 151   /**
 152    * Linked list of sockets we are currently trying out
 153    * (during connect).
 154    */
 155   struct AddressProbe *ap_tail;
 156
 157   /**
 158    * Network address of the other end-point, may be NULL.
 159    */
 160   struct sockaddr *addr;
 161
 162   /**
 163    * Pointer to the hostname if connection was
 164    * created using DNS lookup, otherwise NULL.
 165    */
 166   char *hostname;
 167
 168   /**
 169    * Underlying OS's socket, set to NULL after fatal errors.
 170    */
 171   struct GNUNET_NETWORK_Handle *sock;
 172
 173   /**
 174    * Function to call on data received, NULL if no receive is pending.
 175    */
 176   GNUNET_CONNECTION_Receiver receiver;
 177
 178   /**
 179    * Closure for @e receiver.
 180    */
 181   void *receiver_cls;
 182
 183   /**
 184    * Pointer to our write buffer.
 185    */
 186   char *write_buffer;
 187
 188   /**
 189    * Current size of our @e write_buffer.
 190    */
 191   size_t write_buffer_size;
 192
 193   /**
 194    * Current write-offset in @e write_buffer (where
 195    * would we write next).
 196    */
 197   size_t write_buffer_off;
 198
 199   /**
 200    * Current read-offset in @e write_buffer (how many
 201    * bytes have already been sent).
 202    */
 203   size_t write_buffer_pos;
 204
 205   /**
 206    * Length of @e addr.
 207    */
 208   socklen_t addrlen;
 209
 210   /**
 211    * Read task that we may need to wait for.
 212    */
 213   struct GNUNET_SCHEDULER_Task *read_task;
 214
 215   /**
 216    * Write task that we may need to wait for.
 217    */
 218   struct GNUNET_SCHEDULER_Task *write_task;
 219
 220   /**
 221    * Handle to a pending DNS lookup request.
 222    */
 223   struct GNUNET_RESOLVER_RequestHandle *dns_active;
 224
 225   /**
 226    * The handle we return for #GNUNET_CONNECTION_notify_transmit_ready().
 227    */
 228   struct GNUNET_CONNECTION_TransmitHandle nth;
 229
 230   /**
 231    * Timeout for receiving (in absolute time).
 232    */
 233   struct GNUNET_TIME_Absolute receive_timeout;
 234
 235   /**
 236    * Maximum number of bytes to read (for receiving).
 237    */
 238   size_t max;
 239
 240   /**
 241    * Port to connect to.
 242    */
 243   uint16_t port;
 244
 245   /**
 246    * When shutdown, do not ever actually close the socket, but
 247    * free resources.  Only should ever be set if using program
 248    * termination as a signal (because only then will the leaked
 249    * socket be freed!)
 250    */
 251   int8_t persist;
 252
 253   /**
 254    * Usually 0.  Set to 1 if this handle is in use, and should
 255    * #GNUNET_CONNECTION_destroy() be called right now, the action needs
 256    * to be deferred by setting it to -1.
 257    */
 258   int8_t destroy_later;
 259
 260   /**
 261    * Handle to subsequent connection after proxy handshake completes,
 262    */
 263   struct GNUNET_CONNECTION_Handle *proxy_handshake;
 264
 265 };
 266
 267
 268 /**
 269  * Set the persist option on this connection handle.  Indicates
 270  * that the underlying socket or fd should never really be closed.
 271  * Used for indicating process death.
 272  *
 273  * @param connection the connection to set persistent
 274  */
 275 void
 276 GNUNET_CONNECTION_persist_ (struct GNUNET_CONNECTION_Handle *connection)
 277 {
 278   connection->persist = GNUNET_YES;
 279 }
 280
 281
 282 /**
 283  * Disable the "CORK" feature for communication with the given connection,
 284  * forcing the OS to immediately flush the buffer on transmission
 285  * instead of potentially buffering multiple messages.  Essentially
 286  * reduces the OS send buffers to zero.
 287  * Used to make sure that the last messages sent through the connection
 288  * reach the other side before the process is terminated.
 289  *
 290  * @param connection the connection to make flushing and blocking
 291  * @return #GNUNET_OK on success
 292  */
 293 int
 294 GNUNET_CONNECTION_disable_corking (struct GNUNET_CONNECTION_Handle *connection)
 295 {
 296   return GNUNET_NETWORK_socket_disable_corking (connection->sock);
 297 }
 298
 299
 300 /**
 301  * Create a connection handle by boxing an existing OS socket.  The OS
 302  * socket should henceforth be no longer used directly.
 303  * #GNUNET_connection_destroy() will close it.
 304  *
 305  * @param osSocket existing socket to box
 306  * @return the boxed connection handle
 307  */
 308 struct GNUNET_CONNECTION_Handle *
 309 GNUNET_CONNECTION_create_from_existing (struct GNUNET_NETWORK_Handle *osSocket)
 310 {
 311   struct GNUNET_CONNECTION_Handle *connection;
 312
 313   connection = GNUNET_new (struct GNUNET_CONNECTION_Handle);
 314   connection->write_buffer_size = GNUNET_MIN_MESSAGE_SIZE;
 315   connection->write_buffer = GNUNET_malloc (connection->write_buffer_size);
 316   connection->sock = osSocket;
 317   return connection;
 318 }
 319
 320
 321 /**
 322  * Create a connection handle by accepting on a listen socket.  This
 323  * function may block if the listen socket has no connection ready.
 324  *
 325  * @param access_cb function to use to check if access is allowed
 326  * @param access_cb_cls closure for @a access_cb
 327  * @param lsock listen socket
 328  * @return the connection handle, NULL on error
 329  */
 330 struct GNUNET_CONNECTION_Handle *
 331 GNUNET_CONNECTION_create_from_accept (GNUNET_CONNECTION_AccessCheck access_cb,
 332                                       void *access_cb_cls,
 333                                       struct GNUNET_NETWORK_Handle *lsock)
 334 {
 335   struct GNUNET_CONNECTION_Handle *connection;
 336   char addr[128];
 337   socklen_t addrlen;
 338   struct GNUNET_NETWORK_Handle *sock;
 339   int aret;
 340   struct sockaddr_in *v4;
 341   struct sockaddr_in6 *v6;
 342   struct sockaddr *sa;
 343   void *uaddr;
 344 #ifdef SO_PEERCRED
 345   struct ucred uc;
 346   socklen_t olen;
 347 #endif
 348   struct GNUNET_CONNECTION_Credentials *gcp;
 349 #if HAVE_GETPEEREID || defined(SO_PEERCRED) || HAVE_GETPEERUCRED
 350   struct GNUNET_CONNECTION_Credentials gc;
 351
 352   gc.uid = 0;
 353   gc.gid = 0;
 354 #endif
 355
 356   addrlen = sizeof (addr);
 357   sock =
 358       GNUNET_NETWORK_socket_accept (lsock,
 359                                     (struct sockaddr *) &addr,
 360                                     &addrlen);
 361   if (NULL == sock)
 362   {
 363     if (EAGAIN != errno)
 364       LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "accept");
 365     return NULL;
 366   }
 367   if ((addrlen > sizeof (addr)) || (addrlen < sizeof (sa_family_t)))
 368   {
 369     GNUNET_break (0);
 370     GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (sock));
 371     return NULL;
 372   }
 373
 374   sa = (struct sockaddr *) addr;
 375   v6 = (struct sockaddr_in6 *) addr;
 376   if ( (AF_INET6 == sa->sa_family) &&
 377        (IN6_IS_ADDR_V4MAPPED (&v6->sin6_addr)) )
 378   {
 379     /* convert to V4 address */
 380     v4 = GNUNET_new (struct sockaddr_in);
 381     memset (v4, 0, sizeof (struct sockaddr_in));
 382     v4->sin_family = AF_INET;
 383 #if HAVE_SOCKADDR_IN_SIN_LEN
 384     v4->sin_len = (u_char) sizeof (struct sockaddr_in);
 385 #endif
 386     GNUNET_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     GNUNET_memcpy (uaddr, addr, addrlen);
 398   }
 399   gcp = NULL;
 400   if (AF_UNIX == sa->sa_family)
 401   {
 402 #if HAVE_GETPEEREID
 403     /* most BSDs */
 404     if (0 == getpeereid (GNUNET_NETWORK_get_fd (sock),
 405                          &gc.uid,
 406                          &gc.gid))
 407       gcp = &gc;
 408 #else
 409 #ifdef SO_PEERCRED
 410     /* largely traditional GNU/Linux */
 411     olen = sizeof (uc);
 412     if ( (0 ==
 413           getsockopt (GNUNET_NETWORK_get_fd (sock),
 414                       SOL_SOCKET,
 415                       SO_PEERCRED,
 416                       &uc,
 417                       &olen)) &&
 418          (olen == sizeof (uc)) )
 419     {
 420       gc.uid = uc.uid;
 421       gc.gid = uc.gid;
 422       gcp = &gc;
 423     }
 424 #else
 425 #if HAVE_GETPEERUCRED
 426     /* this is for Solaris 10 */
 427     ucred_t *uc;
 428
 429     uc = NULL;
 430     if (0 == getpeerucred (GNUNET_NETWORK_get_fd (sock), &uc))
 431     {
 432       gc.uid = ucred_geteuid (uc);
 433       gc.gid = ucred_getegid (uc);
 434       gcp = &gc;
 435     }
 436     ucred_free (uc);
 437 #endif
 438 #endif
 439 #endif
 440   }
 441
 442   if ( (NULL != access_cb) &&
 443        (GNUNET_YES != (aret = access_cb (access_cb_cls,
 444                                          gcp,
 445                                          uaddr,
 446                                          addrlen))) )
 447   {
 448     if (GNUNET_NO == aret)
 449       LOG (GNUNET_ERROR_TYPE_INFO,
 450            _("Access denied to `%s'\n"),
 451            GNUNET_a2s (uaddr,
 452                        addrlen));
 453     GNUNET_break (GNUNET_OK ==
 454                   GNUNET_NETWORK_socket_shutdown (sock,
 455                                                   SHUT_RDWR));
 456     GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (sock));
 457     GNUNET_free (uaddr);
 458     return NULL;
 459   }
 460   connection = GNUNET_new (struct GNUNET_CONNECTION_Handle);
 461   connection->write_buffer_size = GNUNET_MIN_MESSAGE_SIZE;
 462   connection->write_buffer = GNUNET_malloc (connection->write_buffer_size);
 463   connection->addr = uaddr;
 464   connection->addrlen = addrlen;
 465   connection->sock = sock;
 466   LOG (GNUNET_ERROR_TYPE_INFO,
 467        _("Accepting connection from `%s': %p\n"),
 468        GNUNET_a2s (uaddr,
 469                    addrlen),
 470        connection);
 471   return connection;
 472 }
 473
 474
 475 /**
 476  * Obtain the network address of the other party.
 477  *
 478  * @param connection the client to get the address for
 479  * @param addr where to store the address
 480  * @param addrlen where to store the length of the @a addr
 481  * @return #GNUNET_OK on success
 482  */
 483 int
 484 GNUNET_CONNECTION_get_address (struct GNUNET_CONNECTION_Handle *connection,
 485                                void **addr,
 486                                size_t *addrlen)
 487 {
 488   if ((NULL == connection->addr) || (0 == connection->addrlen))
 489     return GNUNET_NO;
 490   *addr = GNUNET_malloc (connection->addrlen);
 491   GNUNET_memcpy (*addr, connection->addr, connection->addrlen);
 492   *addrlen = connection->addrlen;
 493   return GNUNET_OK;
 494 }
 495
 496
 497 /**
 498  * Tell the receiver callback that we had an IO error.
 499  *
 500  * @param connection connection to signal error
 501  * @param errcode error code to send
 502  */
 503 static void
 504 signal_receive_error (struct GNUNET_CONNECTION_Handle *connection,
 505                       int errcode)
 506 {
 507   GNUNET_CONNECTION_Receiver receiver;
 508
 509   LOG (GNUNET_ERROR_TYPE_DEBUG,
 510        "Receive encounters error (%s), connection closed (%p)\n",
 511        STRERROR (errcode),
 512        connection);
 513   GNUNET_assert (NULL != (receiver = connection->receiver));
 514   connection->receiver = NULL;
 515   receiver (connection->receiver_cls,
 516             NULL,
 517             0,
 518             connection->addr,
 519             connection->addrlen,
 520             errcode);
 521 }
 522
 523
 524 /**
 525  * Tell the receiver callback that a timeout was reached.
 526  *
 527  * @param connection connection to signal for
 528  */
 529 static void
 530 signal_receive_timeout (struct GNUNET_CONNECTION_Handle *connection)
 531 {
 532   GNUNET_CONNECTION_Receiver receiver;
 533
 534   LOG (GNUNET_ERROR_TYPE_DEBUG,
 535        "Connection signals timeout to receiver (%p)!\n",
 536        connection);
 537   GNUNET_assert (NULL != (receiver = connection->receiver));
 538   connection->receiver = NULL;
 539   receiver (connection->receiver_cls, NULL, 0, NULL, 0, 0);
 540 }
 541
 542
 543 /**
 544  * We failed to transmit data to the service, signal the error.
 545  *
 546  * @param connection handle that had trouble
 547  * @param ecode error code (errno)
 548  */
 549 static void
 550 signal_transmit_error (struct GNUNET_CONNECTION_Handle *connection,
 551                        int ecode)
 552 {
 553   GNUNET_CONNECTION_TransmitReadyNotify notify;
 554
 555   LOG (GNUNET_ERROR_TYPE_DEBUG,
 556        "Transmission encounterd error (%s), connection closed (%p)\n",
 557        STRERROR (ecode),
 558        connection);
 559   if (NULL != connection->sock)
 560   {
 561     (void) GNUNET_NETWORK_socket_shutdown (connection->sock,
 562                                            SHUT_RDWR);
 563     GNUNET_break (GNUNET_OK ==
 564                   GNUNET_NETWORK_socket_close (connection->sock));
 565     connection->sock = NULL;
 566     GNUNET_assert (NULL == connection->write_task);
 567   }
 568   if (NULL != connection->read_task)
 569   {
 570     /* send errors trigger read errors... */
 571     GNUNET_SCHEDULER_cancel (connection->read_task);
 572     connection->read_task = NULL;
 573     signal_receive_timeout (connection);
 574     return;
 575   }
 576   if (NULL == connection->nth.notify_ready)
 577     return;                     /* nobody to tell about it */
 578   notify = connection->nth.notify_ready;
 579   connection->nth.notify_ready = NULL;
 580   notify (connection->nth.notify_ready_cls,
 581           0,
 582           NULL);
 583 }
 584
 585
 586 /**
 587  * We've failed for good to establish a connection (timeout or
 588  * no more addresses to try).
 589  *
 590  * @param connection the connection we tried to establish
 591  */
 592 static void
 593 connect_fail_continuation (struct GNUNET_CONNECTION_Handle *connection)
 594 {
 595   LOG (GNUNET_ERROR_TYPE_INFO,
 596        "Failed to establish TCP connection to `%s:%u', no further addresses to try.\n",
 597        connection->hostname,
 598     connection->port);
 599   GNUNET_break (NULL == connection->ap_head);
 600   GNUNET_break (NULL == connection->ap_tail);
 601   GNUNET_break (GNUNET_NO == connection->dns_active);
 602   GNUNET_break (NULL == connection->sock);
 603   GNUNET_assert (NULL == connection->write_task);
 604   GNUNET_assert (NULL == connection->proxy_handshake);
 605
 606   /* signal errors for jobs that used to wait on the connection */
 607   connection->destroy_later = 1;
 608   if (NULL != connection->receiver)
 609     signal_receive_error (connection,
 610                           ECONNREFUSED);
 611   if (NULL != connection->nth.notify_ready)
 612   {
 613     GNUNET_assert (NULL != connection->nth.timeout_task);
 614     GNUNET_SCHEDULER_cancel (connection->nth.timeout_task);
 615     connection->nth.timeout_task = NULL;
 616     signal_transmit_error (connection,
 617                            ECONNREFUSED);
 618   }
 619   if (-1 == connection->destroy_later)
 620   {
 621     /* do it now */
 622     connection->destroy_later = 0;
 623     GNUNET_CONNECTION_destroy (connection);
 624     return;
 625   }
 626   connection->destroy_later = 0;
 627 }
 628
 629
 630 /**
 631  * We are ready to transmit (or got a timeout).
 632  *
 633  * @param cls our connection handle
 634  */
 635 static void
 636 transmit_ready (void *cls);
 637
 638
 639 /**
 640  * This function is called once we either timeout or have data ready
 641  * to read.
 642  *
 643  * @param cls connection to read from
 644  */
 645 static void
 646 receive_ready (void *cls);
 647
 648
 649 /**
 650  * We've succeeded in establishing a connection.
 651  *
 652  * @param connection the connection we tried to establish
 653  */
 654 static void
 655 connect_success_continuation (struct GNUNET_CONNECTION_Handle *connection)
 656 {
 657   LOG (GNUNET_ERROR_TYPE_DEBUG,
 658        "Connection to `%s' succeeded! (%p)\n",
 659        GNUNET_a2s (connection->addr,
 660                    connection->addrlen),
 661        connection);
 662   /* trigger jobs that waited for the connection */
 663   if (NULL != connection->receiver)
 664   {
 665     LOG (GNUNET_ERROR_TYPE_DEBUG,
 666          "Connection succeeded, starting with receiving data (%p)\n",
 667          connection);
 668     GNUNET_assert (NULL == connection->read_task);
 669     connection->read_task =
 670       GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_absolute_get_remaining
 671                                      (connection->receive_timeout),
 672                                      connection->sock,
 673                                      &receive_ready, connection);
 674   }
 675   if (NULL != connection->nth.notify_ready)
 676   {
 677     LOG (GNUNET_ERROR_TYPE_DEBUG,
 678          "Connection succeeded, starting with sending data (%p)\n",
 679          connection);
 680     GNUNET_assert (connection->nth.timeout_task != NULL);
 681     GNUNET_SCHEDULER_cancel (connection->nth.timeout_task);
 682     connection->nth.timeout_task = NULL;
 683     GNUNET_assert (connection->write_task == NULL);
 684     connection->write_task =
 685         GNUNET_SCHEDULER_add_write_net (GNUNET_TIME_absolute_get_remaining
 686                                         (connection->nth.transmit_timeout), connection->sock,
 687                                         &transmit_ready, connection);
 688   }
 689 }
 690
 691
 692 /**
 693  * Scheduler let us know that we're either ready to write on the
 694  * socket OR connect timed out.  Do the right thing.
 695  *
 696  * @param cls the `struct AddressProbe *` with the address that we are probing
 697  */
 698 static void
 699 connect_probe_continuation (void *cls)
 700 {
 701   struct AddressProbe *ap = cls;
 702   struct GNUNET_CONNECTION_Handle *connection = ap->connection;
 703   const struct GNUNET_SCHEDULER_TaskContext *tc;
 704   struct AddressProbe *pos;
 705   int error;
 706   socklen_t len;
 707
 708   GNUNET_assert (NULL != ap->sock);
 709   GNUNET_CONTAINER_DLL_remove (connection->ap_head,
 710                                connection->ap_tail,
 711                                ap);
 712   len = sizeof (error);
 713   errno = 0;
 714   error = 0;
 715   tc = GNUNET_SCHEDULER_get_task_context ();
 716   if ( (0 == (tc->reason & GNUNET_SCHEDULER_REASON_WRITE_READY)) ||
 717        (GNUNET_OK !=
 718         GNUNET_NETWORK_socket_getsockopt (ap->sock,
 719                                           SOL_SOCKET,
 720                                           SO_ERROR,
 721                                           &error,
 722                                           &len)) ||
 723        (0 != error) )
 724   {
 725     GNUNET_break (GNUNET_OK ==
 726                   GNUNET_NETWORK_socket_close (ap->sock));
 727     GNUNET_free (ap);
 728     if ( (NULL == connection->ap_head) &&
 729          (GNUNET_NO == connection->dns_active) &&
 730          (NULL == connection->proxy_handshake) )
 731       connect_fail_continuation (connection);
 732     return;
 733   }
 734   GNUNET_assert (NULL == connection->sock);
 735   connection->sock = ap->sock;
 736   GNUNET_assert (NULL == connection->addr);
 737   connection->addr = GNUNET_malloc (ap->addrlen);
 738   GNUNET_memcpy (connection->addr, ap->addr, ap->addrlen);
 739   connection->addrlen = ap->addrlen;
 740   GNUNET_free (ap);
 741   /* cancel all other attempts */
 742   while (NULL != (pos = connection->ap_head))
 743   {
 744     GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (pos->sock));
 745     GNUNET_SCHEDULER_cancel (pos->task);
 746     GNUNET_CONTAINER_DLL_remove (connection->ap_head,
 747                                  connection->ap_tail,
 748                                  pos);
 749     GNUNET_free (pos);
 750   }
 751   connect_success_continuation (connection);
 752 }
 753
 754
 755 /**
 756  * Try to establish a connection given the specified address.
 757  * This function is called by the resolver once we have a DNS reply.
 758  *
 759  * @param cls our `struct GNUNET_CONNECTION_Handle *`
 760  * @param addr address to try, NULL for "last call"
 761  * @param addrlen length of @a addr
 762  */
 763 static void
 764 try_connect_using_address (void *cls,
 765                            const struct sockaddr *addr,
 766                            socklen_t addrlen)
 767 {
 768   struct GNUNET_CONNECTION_Handle *connection = cls;
 769   struct AddressProbe *ap;
 770   struct GNUNET_TIME_Relative delay;
 771
 772   if (NULL == addr)
 773   {
 774     connection->dns_active = NULL;
 775     if ((NULL == connection->ap_head) &&
 776         (NULL == connection->sock) &&
 777         (NULL == connection->proxy_handshake))
 778       connect_fail_continuation (connection);
 779     return;
 780   }
 781   if (NULL != connection->sock)
 782     return;                     /* already connected */
 783   GNUNET_assert (NULL == connection->addr);
 784   /* try to connect */
 785   LOG (GNUNET_ERROR_TYPE_DEBUG,
 786        "Trying to connect using address `%s:%u/%s:%u'\n",
 787        connection->hostname,
 788        connection->port,
 789        GNUNET_a2s (addr, addrlen),
 790        connection->port);
 791   ap = GNUNET_malloc (sizeof (struct AddressProbe) + addrlen);
 792   ap->addr = (const struct sockaddr *) &ap[1];
 793   GNUNET_memcpy (&ap[1], addr, addrlen);
 794   ap->addrlen = addrlen;
 795   ap->connection = connection;
 796
 797   switch (ap->addr->sa_family)
 798   {
 799   case AF_INET:
 800     ((struct sockaddr_in *) ap->addr)->sin_port = htons (connection->port);
 801     break;
 802   case AF_INET6:
 803     ((struct sockaddr_in6 *) ap->addr)->sin6_port = htons (connection->port);
 804     break;
 805   default:
 806     GNUNET_break (0);
 807     GNUNET_free (ap);
 808     return;                     /* not supported by us */
 809   }
 810   ap->sock = GNUNET_NETWORK_socket_create (ap->addr->sa_family,
 811                                            SOCK_STREAM, 0);
 812   if (NULL == ap->sock)
 813   {
 814     GNUNET_free (ap);
 815     return;                     /* not supported by OS */
 816   }
 817   LOG (GNUNET_ERROR_TYPE_INFO,
 818        "Trying to connect to `%s' (%p)\n",
 819        GNUNET_a2s (ap->addr, ap->addrlen),
 820        connection);
 821   if ((GNUNET_OK !=
 822        GNUNET_NETWORK_socket_connect (ap->sock,
 823                                       ap->addr,
 824                                       ap->addrlen)) &&
 825       (EINPROGRESS != errno))
 826   {
 827     /* maybe refused / unsupported address, try next */
 828     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 (connection->ap_head, connection->ap_tail, ap);
 834   delay = CONNECT_RETRY_TIMEOUT;
 835   if (NULL != connection->nth.notify_ready)
 836     delay = GNUNET_TIME_relative_min (delay,
 837                                       GNUNET_TIME_absolute_get_remaining (connection->nth.transmit_timeout));
 838   if (NULL != connection->receiver)
 839     delay = GNUNET_TIME_relative_min (delay,
 840                                       GNUNET_TIME_absolute_get_remaining (connection->receive_timeout));
 841   ap->task = GNUNET_SCHEDULER_add_write_net (delay,
 842                                              ap->sock,
 843                                              &connect_probe_continuation,
 844                                              ap);
 845 }
 846
 847
 848 /**
 849  * Create a connection handle by (asynchronously) connecting to a host.
 850  * This function returns immediately, even if the connection has not
 851  * yet been established.  This function only creates TCP connections.
 852  *
 853  * @param cfg configuration to use
 854  * @param hostname name of the host to connect to
 855  * @param port port to connect to
 856  * @return the connection handle
 857  */
 858 struct GNUNET_CONNECTION_Handle *
 859 GNUNET_CONNECTION_create_from_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
 860                                        const char *hostname,
 861                                        uint16_t port)
 862 {
 863   struct GNUNET_CONNECTION_Handle *connection;
 864
 865   GNUNET_assert (0 < strlen (hostname));        /* sanity check */
 866   connection = GNUNET_new (struct GNUNET_CONNECTION_Handle);
 867   connection->cfg = cfg;
 868   connection->write_buffer_size = GNUNET_MIN_MESSAGE_SIZE;
 869   connection->write_buffer = GNUNET_malloc (connection->write_buffer_size);
 870   connection->port = port;
 871   connection->hostname = GNUNET_strdup (hostname);
 872   connection->dns_active =
 873       GNUNET_RESOLVER_ip_get (connection->hostname,
 874                               AF_UNSPEC,
 875                               CONNECT_RETRY_TIMEOUT,
 876                               &try_connect_using_address,
 877                               connection);
 878   return connection;
 879 }
 880
 881
 882 /**
 883  * Create a connection handle by connecting to a UNIX domain service.
 884  * This function returns immediately, even if the connection has not
 885  * yet been established.  This function only creates UNIX connections.
 886  *
 887  * @param cfg configuration to use
 888  * @param unixpath path to connect to
 889  * @return the connection handle, NULL on systems without UNIX support
 890  */
 891 struct GNUNET_CONNECTION_Handle *
 892 GNUNET_CONNECTION_create_from_connect_to_unixpath (const struct GNUNET_CONFIGURATION_Handle *cfg,
 893                                                    const char *unixpath)
 894 {
 895 #ifdef AF_UNIX
 896   struct GNUNET_CONNECTION_Handle *connection;
 897   struct sockaddr_un *un;
 898
 899   GNUNET_assert (0 < strlen (unixpath));        /* sanity check */
 900   un = GNUNET_new (struct sockaddr_un);
 901   un->sun_family = AF_UNIX;
 902   strncpy (un->sun_path, unixpath, sizeof (un->sun_path) - 1);
 903 #ifdef LINUX
 904   {
 905     int abstract;
 906
 907     abstract = GNUNET_CONFIGURATION_get_value_yesno (cfg,
 908                                                      "TESTING",
 909                                                      "USE_ABSTRACT_SOCKETS");
 910     if (GNUNET_YES == abstract)
 911       un->sun_path[0] = '\0';
 912   }
 913 #endif
 914 #if HAVE_SOCKADDR_UN_SUN_LEN
 915   un->sun_len = (u_char) sizeof (struct sockaddr_un);
 916 #endif
 917   connection = GNUNET_new (struct GNUNET_CONNECTION_Handle);
 918   connection->cfg = cfg;
 919   connection->write_buffer_size = GNUNET_MIN_MESSAGE_SIZE;
 920   connection->write_buffer = GNUNET_malloc (connection->write_buffer_size);
 921   connection->port = 0;
 922   connection->hostname = NULL;
 923   connection->addr = (struct sockaddr *) un;
 924   connection->addrlen = sizeof (struct sockaddr_un);
 925   connection->sock = GNUNET_NETWORK_socket_create (AF_UNIX,
 926                                                    SOCK_STREAM,
 927                                                    0);
 928   if (NULL == connection->sock)
 929   {
 930     GNUNET_free (connection->addr);
 931     GNUNET_free (connection->write_buffer);
 932     GNUNET_free (connection);
 933     return NULL;
 934   }
 935   if ( (GNUNET_OK !=
 936         GNUNET_NETWORK_socket_connect (connection->sock,
 937                                        connection->addr,
 938                                        connection->addrlen)) &&
 939        (EINPROGRESS != errno) )
 940   {
 941     /* Just return; we expect everything to work eventually so don't fail HARD */
 942     GNUNET_break (GNUNET_OK ==
 943                   GNUNET_NETWORK_socket_close (connection->sock));
 944     connection->sock = NULL;
 945     return connection;
 946   }
 947   connect_success_continuation (connection);
 948   return connection;
 949 #else
 950   return NULL;
 951 #endif
 952 }
 953
 954
 955 /**
 956  * Create a connection handle by (asynchronously) connecting to a host.
 957  * This function returns immediately, even if the connection has not
 958  * yet been established.  This function only creates TCP connections.
 959  *
 960  * @param s socket to connect
 961  * @param serv_addr server address
 962  * @param addrlen length of @a serv_addr
 963  * @return the connection handle
 964  */
 965 struct GNUNET_CONNECTION_Handle *
 966 GNUNET_CONNECTION_connect_socket (struct GNUNET_NETWORK_Handle *s,
 967                                   const struct sockaddr *serv_addr,
 968                                   socklen_t addrlen)
 969 {
 970   struct GNUNET_CONNECTION_Handle *connection;
 971
 972   if ( (GNUNET_OK !=
 973         GNUNET_NETWORK_socket_connect (s, serv_addr, addrlen)) &&
 974        (EINPROGRESS != errno) )
 975   {
 976     /* maybe refused / unsupported address, try next */
 977     LOG_STRERROR (GNUNET_ERROR_TYPE_DEBUG,
 978                   "connect");
 979     LOG (GNUNET_ERROR_TYPE_DEBUG,
 980          "Attempt to connect to `%s' failed\n",
 981          GNUNET_a2s (serv_addr,
 982                      addrlen));
 983     GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (s));
 984     return NULL;
 985   }
 986   connection = GNUNET_CONNECTION_create_from_existing (s);
 987   connection->addr = GNUNET_malloc (addrlen);
 988   GNUNET_memcpy (connection->addr, serv_addr, addrlen);
 989   connection->addrlen = addrlen;
 990   LOG (GNUNET_ERROR_TYPE_INFO,
 991        "Trying to connect to `%s' (%p)\n",
 992        GNUNET_a2s (serv_addr, addrlen),
 993        connection);
 994   return connection;
 995 }
 996
 997
 998 /**
 999  * Create a connection handle by creating a socket and
1000  * (asynchronously) connecting to a host.  This function returns
1001  * immediately, even if the connection has not yet been established.
1002  * This function only creates TCP connections.
1003  *
1004  * @param af_family address family to use
1005  * @param serv_addr server address
1006  * @param addrlen length of @a serv_addr
1007  * @return the connection handle
1008  */
1009 struct GNUNET_CONNECTION_Handle *
1010 GNUNET_CONNECTION_create_from_sockaddr (int af_family,
1011                                         const struct sockaddr *serv_addr,
1012                                         socklen_t addrlen)
1013 {
1014   struct GNUNET_NETWORK_Handle *s;
1015
1016   s = GNUNET_NETWORK_socket_create (af_family, SOCK_STREAM, 0);
1017   if (NULL == s)
1018   {
1019     LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING | GNUNET_ERROR_TYPE_BULK,
1020                   "socket");
1021     return NULL;
1022   }
1023   return GNUNET_CONNECTION_connect_socket (s,
1024                                            serv_addr,
1025                                            addrlen);
1026 }
1027
1028
1029 /**
1030  * Check if connection is valid (no fatal errors have happened so far).
1031  * Note that a connection that is still trying to connect is considered
1032  * valid.
1033  *
1034  * @param connection connection to check
1035  * @return #GNUNET_YES if valid, #GNUNET_NO otherwise
1036  */
1037 int
1038 GNUNET_CONNECTION_check (struct GNUNET_CONNECTION_Handle *connection)
1039 {
1040   if ((NULL != connection->ap_head) ||
1041       (NULL != connection->dns_active) ||
1042       (NULL != connection->proxy_handshake))
1043     return GNUNET_YES;          /* still trying to connect */
1044   if ( (0 != connection->destroy_later) ||
1045        (NULL == connection->sock) )
1046     return GNUNET_NO;
1047   return GNUNET_YES;
1048 }
1049
1050
1051 /**
1052  * Close the connection and free associated resources.  There must
1053  * not be any pending requests for reading or writing to the
1054  * connection at this time.
1055  *
1056  * @param connection connection to destroy
1057  */
1058 void
1059 GNUNET_CONNECTION_destroy (struct GNUNET_CONNECTION_Handle *connection)
1060 {
1061   struct AddressProbe *pos;
1062
1063   if (0 != connection->destroy_later)
1064   {
1065     connection->destroy_later = -1;
1066     return;
1067   }
1068   LOG (GNUNET_ERROR_TYPE_DEBUG,
1069        "Shutting down connection (%p)\n",
1070        connection);
1071   GNUNET_assert (NULL == connection->nth.notify_ready);
1072   GNUNET_assert (NULL == connection->receiver);
1073   if (NULL != connection->write_task)
1074   {
1075     GNUNET_SCHEDULER_cancel (connection->write_task);
1076     connection->write_task = NULL;
1077     connection->write_buffer_off = 0;
1078   }
1079   if (NULL != connection->read_task)
1080   {
1081     GNUNET_SCHEDULER_cancel (connection->read_task);
1082     connection->read_task = NULL;
1083   }
1084   if (NULL != connection->nth.timeout_task)
1085   {
1086     GNUNET_SCHEDULER_cancel (connection->nth.timeout_task);
1087     connection->nth.timeout_task = NULL;
1088   }
1089   connection->nth.notify_ready = NULL;
1090   if (NULL != connection->dns_active)
1091   {
1092     GNUNET_RESOLVER_request_cancel (connection->dns_active);
1093     connection->dns_active = NULL;
1094   }
1095   if (NULL != connection->proxy_handshake)
1096   {
1097     /* GNUNET_CONNECTION_destroy (connection->proxy_handshake); */
1098     connection->proxy_handshake->destroy_later = -1;
1099     connection->proxy_handshake = NULL;  /* Not leaked ??? */
1100   }
1101   while (NULL != (pos = connection->ap_head))
1102   {
1103     GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (pos->sock));
1104     GNUNET_SCHEDULER_cancel (pos->task);
1105     GNUNET_CONTAINER_DLL_remove (connection->ap_head,
1106                                  connection->ap_tail,
1107                                  pos);
1108     GNUNET_free (pos);
1109   }
1110   if ( (NULL != connection->sock) &&
1111        (GNUNET_YES != connection->persist) )
1112   {
1113     if ((GNUNET_OK !=
1114          GNUNET_NETWORK_socket_shutdown (connection->sock,
1115                                          SHUT_RDWR)) &&
1116         (ENOTCONN != errno) &&
1117         (ECONNRESET != errno) )
1118       LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING,
1119                     "shutdown");
1120   }
1121   if (NULL != connection->sock)
1122   {
1123     if (GNUNET_YES != connection->persist)
1124     {
1125       GNUNET_break (GNUNET_OK ==
1126                     GNUNET_NETWORK_socket_close (connection->sock));
1127     }
1128     else
1129     {
1130       GNUNET_NETWORK_socket_free_memory_only_ (connection->sock); /* at least no memory leak (we deliberately
1131                                                                    * leak the socket in this special case) ... */
1132     }
1133   }
1134   GNUNET_free_non_null (connection->addr);
1135   GNUNET_free_non_null (connection->hostname);
1136   GNUNET_free (connection->write_buffer);
1137   GNUNET_free (connection);
1138 }
1139
1140
1141 /**
1142  * This function is called once we either timeout
1143  * or have data ready to read.
1144  *
1145  * @param cls connection to read from
1146  */
1147 static void
1148 receive_ready (void *cls)
1149 {
1150   struct GNUNET_CONNECTION_Handle *connection = cls;
1151   const struct GNUNET_SCHEDULER_TaskContext *tc;
1152   char buffer[connection->max];
1153   ssize_t ret;
1154   GNUNET_CONNECTION_Receiver receiver;
1155
1156   connection->read_task = NULL;
1157   tc = GNUNET_SCHEDULER_get_task_context ();
1158   if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_TIMEOUT))
1159   {
1160     LOG (GNUNET_ERROR_TYPE_DEBUG,
1161          "Receive from `%s' encounters error: timeout (%s, %p)\n",
1162          GNUNET_a2s (connection->addr,
1163                      connection->addrlen),
1164          GNUNET_STRINGS_relative_time_to_string (GNUNET_TIME_absolute_get_duration (connection->receive_timeout),
1165                                                  GNUNET_YES),
1166          connection);
1167     signal_receive_timeout (connection);
1168     return;
1169   }
1170   if (NULL == connection->sock)
1171   {
1172     /* connect failed for good */
1173     signal_receive_error (connection, ECONNREFUSED);
1174     return;
1175   }
1176   GNUNET_assert (GNUNET_NETWORK_fdset_isset (tc->read_ready,
1177                                              connection->sock));
1178 RETRY:
1179   ret = GNUNET_NETWORK_socket_recv (connection->sock,
1180                                     buffer,
1181                                     connection->max);
1182   if (-1 == ret)
1183   {
1184     if (EINTR == errno)
1185       goto RETRY;
1186     signal_receive_error (connection, errno);
1187     return;
1188   }
1189   LOG (GNUNET_ERROR_TYPE_DEBUG,
1190        "receive_ready read %u/%u bytes from `%s' (%p)!\n",
1191        (unsigned int) ret,
1192        connection->max,
1193        GNUNET_a2s (connection->addr,
1194                    connection->addrlen),
1195        connection);
1196   GNUNET_assert (NULL != (receiver = connection->receiver));
1197   connection->receiver = NULL;
1198   receiver (connection->receiver_cls,
1199             buffer,
1200             ret,
1201             connection->addr,
1202             connection->addrlen,
1203             0);
1204 }
1205
1206
1207 /**
1208  * Receive data from the given connection.  Note that this function
1209  * will call @a receiver asynchronously using the scheduler.  It will
1210  * "immediately" return.  Note that there MUST only be one active
1211  * receive call per connection at any given point in time (so do not
1212  * call receive again until the receiver callback has been invoked).
1213  *
1214  * @param connection connection handle
1215  * @param max maximum number of bytes to read
1216  * @param timeout maximum amount of time to wait
1217  * @param receiver function to call with received data
1218  * @param receiver_cls closure for @a receiver
1219  * @return #GNUNET_SYSERR if @a connection died (receiver was
1220  *          called with error)
1221  */
1222 int
1223 GNUNET_CONNECTION_receive (struct GNUNET_CONNECTION_Handle *connection,
1224                            size_t max,
1225                            struct GNUNET_TIME_Relative timeout,
1226                            GNUNET_CONNECTION_Receiver receiver,
1227                            void *receiver_cls)
1228 {
1229   GNUNET_assert ((NULL == connection->read_task) &&
1230                  (NULL == connection->receiver));
1231   GNUNET_assert (NULL != receiver);
1232   connection->receiver = receiver;
1233   connection->receiver_cls = receiver_cls;
1234   connection->receive_timeout = GNUNET_TIME_relative_to_absolute (timeout);
1235   connection->max = max;
1236   if (NULL != connection->sock)
1237   {
1238     connection->read_task =
1239       GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_absolute_get_remaining
1240                                      (connection->receive_timeout),
1241                                      connection->sock,
1242                                      &receive_ready,
1243                                      connection);
1244     return GNUNET_OK;
1245   }
1246   if ((NULL == connection->dns_active) &&
1247       (NULL == connection->ap_head) &&
1248       (NULL == connection->proxy_handshake))
1249   {
1250     connection->receiver = NULL;
1251     receiver (receiver_cls,
1252               NULL, 0,
1253               NULL, 0,
1254               ETIMEDOUT);
1255     return GNUNET_SYSERR;
1256   }
1257   return GNUNET_OK;
1258 }
1259
1260
1261 /**
1262  * Cancel receive job on the given connection.  Note that the
1263  * receiver callback must not have been called yet in order
1264  * for the cancellation to be valid.
1265  *
1266  * @param connection connection handle
1267  * @return closure of the original receiver callback closure
1268  */
1269 void *
1270 GNUNET_CONNECTION_receive_cancel (struct GNUNET_CONNECTION_Handle *connection)
1271 {
1272   if (NULL != connection->read_task)
1273   {
1274     GNUNET_assert (connection ==
1275                    GNUNET_SCHEDULER_cancel (connection->read_task));
1276     connection->read_task = NULL;
1277   }
1278   connection->receiver = NULL;
1279   return connection->receiver_cls;
1280 }
1281
1282
1283 /**
1284  * Try to call the transmit notify method (check if we do
1285  * have enough space available first)!
1286  *
1287  * @param connection connection for which we should do this processing
1288  * @return #GNUNET_YES if we were able to call notify
1289  */
1290 static int
1291 process_notify (struct GNUNET_CONNECTION_Handle *connection)
1292 {
1293   size_t used;
1294   size_t avail;
1295   size_t size;
1296   GNUNET_CONNECTION_TransmitReadyNotify notify;
1297
1298   LOG (GNUNET_ERROR_TYPE_DEBUG,
1299        "process_notify is running\n");
1300   GNUNET_assert (NULL == connection->write_task);
1301   if (NULL == (notify = connection->nth.notify_ready))
1302   {
1303     LOG (GNUNET_ERROR_TYPE_DEBUG,
1304          "No one to notify\n");
1305     return GNUNET_NO;
1306   }
1307   used = connection->write_buffer_off - connection->write_buffer_pos;
1308   avail = connection->write_buffer_size - used;
1309   size = connection->nth.notify_size;
1310   if (size > avail)
1311   {
1312     LOG (GNUNET_ERROR_TYPE_DEBUG,
1313          "Not enough buffer\n");
1314     return GNUNET_NO;
1315   }
1316   connection->nth.notify_ready = NULL;
1317   if (connection->write_buffer_size - connection->write_buffer_off < size)
1318   {
1319     /* need to compact */
1320     memmove (connection->write_buffer,
1321              &connection->write_buffer[connection->write_buffer_pos],
1322              used);
1323     connection->write_buffer_off -= connection->write_buffer_pos;
1324     connection->write_buffer_pos = 0;
1325   }
1326   avail = connection->write_buffer_size - connection->write_buffer_off;
1327   GNUNET_assert (avail >= size);
1328   size =
1329       notify (connection->nth.notify_ready_cls, avail,
1330               &connection->write_buffer[connection->write_buffer_off]);
1331   GNUNET_assert (size <= avail);
1332   if (0 != size)
1333     connection->write_buffer_off += size;
1334   return GNUNET_YES;
1335 }
1336
1337
1338 /**
1339  * Task invoked by the scheduler when a call to transmit
1340  * is timing out (we never got enough buffer space to call
1341  * the callback function before the specified timeout
1342  * expired).
1343  *
1344  * This task notifies the client about the timeout.
1345  *
1346  * @param cls the `struct GNUNET_CONNECTION_Handle`
1347  */
1348 static void
1349 transmit_timeout (void *cls)
1350 {
1351   struct GNUNET_CONNECTION_Handle *connection = cls;
1352   GNUNET_CONNECTION_TransmitReadyNotify notify;
1353
1354   connection->nth.timeout_task = NULL;
1355   LOG (GNUNET_ERROR_TYPE_DEBUG,
1356        "Transmit to `%s:%u/%s' fails, time out reached (%p).\n",
1357        connection->hostname,
1358        connection->port,
1359        GNUNET_a2s (connection->addr,
1360                    connection->addrlen),
1361        connection);
1362   notify = connection->nth.notify_ready;
1363   GNUNET_assert (NULL != notify);
1364   connection->nth.notify_ready = NULL;
1365   notify (connection->nth.notify_ready_cls,
1366           0,
1367           NULL);
1368 }
1369
1370
1371 /**
1372  * Task invoked by the scheduler when we failed to connect
1373  * at the time of being asked to transmit.
1374  *
1375  * This task notifies the client about the error.
1376  *
1377  * @param cls the `struct GNUNET_CONNECTION_Handle`
1378  */
1379 static void
1380 connect_error (void *cls)
1381 {
1382   struct GNUNET_CONNECTION_Handle *connection = cls;
1383   GNUNET_CONNECTION_TransmitReadyNotify notify;
1384
1385   LOG (GNUNET_ERROR_TYPE_DEBUG,
1386        "Transmission request of size %u fails (%s/%u), connection failed (%p).\n",
1387        connection->nth.notify_size,
1388        connection->hostname,
1389        connection->port,
1390        connection);
1391   connection->write_task = NULL;
1392   notify = connection->nth.notify_ready;
1393   connection->nth.notify_ready = NULL;
1394   notify (connection->nth.notify_ready_cls,
1395           0,
1396           NULL);
1397 }
1398
1399
1400 /**
1401  * We are ready to transmit (or got a timeout).
1402  *
1403  * @param cls our connection handle
1404  */
1405 static void
1406 transmit_ready (void *cls)
1407 {
1408   struct GNUNET_CONNECTION_Handle *connection = cls;
1409   GNUNET_CONNECTION_TransmitReadyNotify notify;
1410   const struct GNUNET_SCHEDULER_TaskContext *tc;
1411   ssize_t ret;
1412   size_t have;
1413
1414   LOG (GNUNET_ERROR_TYPE_DEBUG,
1415        "transmit_ready running (%p).\n",
1416        connection);
1417   GNUNET_assert (NULL != connection->write_task);
1418   connection->write_task = NULL;
1419   GNUNET_assert (NULL == connection->nth.timeout_task);
1420   tc = GNUNET_SCHEDULER_get_task_context ();
1421   if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_TIMEOUT))
1422   {
1423     LOG (GNUNET_ERROR_TYPE_DEBUG,
1424          "Transmit to `%s' fails, time out reached (%p).\n",
1425          GNUNET_a2s (connection->addr,
1426                      connection->addrlen),
1427          connection);
1428     notify = connection->nth.notify_ready;
1429     GNUNET_assert (NULL != notify);
1430     connection->nth.notify_ready = NULL;
1431     notify (connection->nth.notify_ready_cls, 0, NULL);
1432     return;
1433   }
1434   GNUNET_assert (NULL != connection->sock);
1435   if (NULL == tc->write_ready)
1436   {
1437     /* special circumstances (in particular, PREREQ_DONE after
1438      * connect): not yet ready to write, but no "fatal" error either.
1439      * Hence retry.  */
1440     goto SCHEDULE_WRITE;
1441   }
1442   if (! GNUNET_NETWORK_fdset_isset (tc->write_ready,
1443                                     connection->sock))
1444   {
1445     GNUNET_assert (NULL == connection->write_task);
1446     /* special circumstances (in particular, shutdown): not yet ready
1447      * to write, but no "fatal" error either.  Hence retry.  */
1448     goto SCHEDULE_WRITE;
1449   }
1450   GNUNET_assert (connection->write_buffer_off >= connection->write_buffer_pos);
1451   if ((NULL != connection->nth.notify_ready) &&
1452       (connection->write_buffer_size < connection->nth.notify_size))
1453   {
1454     connection->write_buffer =
1455         GNUNET_realloc (connection->write_buffer, connection->nth.notify_size);
1456     connection->write_buffer_size = connection->nth.notify_size;
1457   }
1458   process_notify (connection);
1459   have = connection->write_buffer_off - connection->write_buffer_pos;
1460   if (0 == have)
1461   {
1462     /* no data ready for writing, terminate write loop */
1463     return;
1464   }
1465   GNUNET_assert (have <= connection->write_buffer_size);
1466   GNUNET_assert (have + connection->write_buffer_pos <= connection->write_buffer_size);
1467   GNUNET_assert (connection->write_buffer_pos <= connection->write_buffer_size);
1468 RETRY:
1469   ret =
1470       GNUNET_NETWORK_socket_send (connection->sock,
1471                                   &connection->write_buffer[connection->write_buffer_pos],
1472                                   have);
1473   if (-1 == ret)
1474   {
1475     if (EINTR == errno)
1476       goto RETRY;
1477     if (NULL != connection->write_task)
1478     {
1479       GNUNET_SCHEDULER_cancel (connection->write_task);
1480       connection->write_task = NULL;
1481     }
1482     signal_transmit_error (connection, errno);
1483     return;
1484   }
1485   LOG (GNUNET_ERROR_TYPE_DEBUG,
1486        "Connection transmitted %u/%u bytes to `%s' (%p)\n",
1487        (unsigned int) ret,
1488        have,
1489        GNUNET_a2s (connection->addr,
1490                    connection->addrlen),
1491        connection);
1492   connection->write_buffer_pos += ret;
1493   if (connection->write_buffer_pos == connection->write_buffer_off)
1494   {
1495     /* transmitted all pending data */
1496     connection->write_buffer_pos = 0;
1497     connection->write_buffer_off = 0;
1498   }
1499   if ( (0 == connection->write_buffer_off) &&
1500        (NULL == connection->nth.notify_ready) )
1501     return;                     /* all data sent! */
1502   /* not done writing, schedule more */
1503 SCHEDULE_WRITE:
1504   LOG (GNUNET_ERROR_TYPE_DEBUG,
1505        "Re-scheduling transmit_ready (more to do) (%p).\n",
1506        connection);
1507   have = connection->write_buffer_off - connection->write_buffer_pos;
1508   GNUNET_assert ( (NULL != connection->nth.notify_ready) ||
1509                   (have > 0) );
1510   if (NULL == connection->write_task)
1511     connection->write_task =
1512         GNUNET_SCHEDULER_add_write_net ((connection->nth.notify_ready ==
1513                                          NULL) ? GNUNET_TIME_UNIT_FOREVER_REL :
1514                                         GNUNET_TIME_absolute_get_remaining
1515                                         (connection->nth.transmit_timeout),
1516                                         connection->sock,
1517                                         &transmit_ready, connection);
1518 }
1519
1520
1521 /**
1522  * Ask the connection to call us once the specified number of bytes
1523  * are free in the transmission buffer.  Will never call the @a notify
1524  * callback in this task, but always first go into the scheduler.
1525  *
1526  * @param connection connection
1527  * @param size number of bytes to send
1528  * @param timeout after how long should we give up (and call
1529  *        @a notify with buf NULL and size 0)?
1530  * @param notify function to call
1531  * @param notify_cls closure for @a notify
1532  * @return non-NULL if the notify callback was queued,
1533  *         NULL if we are already going to notify someone else (busy)
1534  */
1535 struct GNUNET_CONNECTION_TransmitHandle *
1536 GNUNET_CONNECTION_notify_transmit_ready (struct GNUNET_CONNECTION_Handle *connection,
1537                                          size_t size,
1538                                          struct GNUNET_TIME_Relative timeout,
1539                                          GNUNET_CONNECTION_TransmitReadyNotify notify,
1540                                          void *notify_cls)
1541 {
1542   if (NULL != connection->nth.notify_ready)
1543   {
1544     GNUNET_assert (0);
1545     return NULL;
1546   }
1547   GNUNET_assert (NULL != notify);
1548   GNUNET_assert (size < GNUNET_MAX_MESSAGE_SIZE);
1549   GNUNET_assert (connection->write_buffer_off <= connection->write_buffer_size);
1550   GNUNET_assert (connection->write_buffer_pos <= connection->write_buffer_size);
1551   GNUNET_assert (connection->write_buffer_pos <= connection->write_buffer_off);
1552   connection->nth.notify_ready = notify;
1553   connection->nth.notify_ready_cls = notify_cls;
1554   connection->nth.connection = connection;
1555   connection->nth.notify_size = size;
1556   connection->nth.transmit_timeout = GNUNET_TIME_relative_to_absolute (timeout);
1557   GNUNET_assert (NULL == connection->nth.timeout_task);
1558   if ((NULL == connection->sock) &&
1559       (NULL == connection->ap_head) &&
1560       (NULL == connection->dns_active) &&
1561       (NULL == connection->proxy_handshake))
1562   {
1563     if (NULL != connection->write_task)
1564       GNUNET_SCHEDULER_cancel (connection->write_task);
1565     connection->write_task = GNUNET_SCHEDULER_add_now (&connect_error,
1566                                                        connection);
1567     return &connection->nth;
1568   }
1569   if (NULL != connection->write_task)
1570     return &connection->nth; /* previous transmission still in progress */
1571   if (NULL != connection->sock)
1572   {
1573     /* connected, try to transmit now */
1574     LOG (GNUNET_ERROR_TYPE_DEBUG,
1575          "Scheduling transmission (%p).\n",
1576          connection);
1577     connection->write_task =
1578         GNUNET_SCHEDULER_add_write_net (GNUNET_TIME_absolute_get_remaining
1579                                         (connection->nth.transmit_timeout),
1580                                         connection->sock,
1581                                         &transmit_ready, connection);
1582     return &connection->nth;
1583   }
1584   /* not yet connected, wait for connection */
1585   LOG (GNUNET_ERROR_TYPE_DEBUG,
1586        "Need to wait to schedule transmission for connection, adding timeout task (%p).\n",
1587        connection);
1588   connection->nth.timeout_task =
1589     GNUNET_SCHEDULER_add_delayed (timeout,
1590                                   &transmit_timeout,
1591                                   connection);
1592   return &connection->nth;
1593 }
1594
1595
1596 /**
1597  * Cancel the specified transmission-ready notification.
1598  *
1599  * @param th notification to cancel
1600  */
1601 void
1602 GNUNET_CONNECTION_notify_transmit_ready_cancel (struct GNUNET_CONNECTION_TransmitHandle *th)
1603 {
1604   GNUNET_assert (NULL != th->notify_ready);
1605   th->notify_ready = NULL;
1606   if (NULL != th->timeout_task)
1607   {
1608     GNUNET_SCHEDULER_cancel (th->timeout_task);
1609     th->timeout_task = NULL;
1610   }
1611   if (NULL != th->connection->write_task)
1612   {
1613     GNUNET_SCHEDULER_cancel (th->connection->write_task);
1614     th->connection->write_task = NULL;
1615   }
1616 }
1617
1618
1619 /**
1620  * Create a connection to be proxied using a given connection.
1621  *
1622  * @param cph connection to proxy server
1623  * @return connection to be proxied
1624  */
1625 struct GNUNET_CONNECTION_Handle *
1626 GNUNET_CONNECTION_create_proxied_from_handshake (struct GNUNET_CONNECTION_Handle *cph)
1627 {
1628   struct GNUNET_CONNECTION_Handle *proxied = GNUNET_CONNECTION_create_from_existing (NULL);
1629
1630   proxied->proxy_handshake = cph;
1631   return proxied;
1632 }
1633
1634
1635 /**
1636  * Activate proxied connection and destroy initial proxy handshake connection.
1637  * There must not be any pending requests for reading or writing to the
1638  * proxy hadshake connection at this time.
1639  *
1640  * @param proxied connection connection to proxy server
1641  */
1642 void
1643 GNUNET_CONNECTION_acivate_proxied (struct GNUNET_CONNECTION_Handle *proxied)
1644 {
1645   struct GNUNET_CONNECTION_Handle *cph = proxied->proxy_handshake;
1646
1647   GNUNET_assert (NULL != cph);
1648   GNUNET_assert (NULL == proxied->sock);
1649   GNUNET_assert (NULL != cph->sock);
1650   proxied->sock = cph->sock;
1651   cph->sock = NULL;
1652   GNUNET_CONNECTION_destroy (cph);
1653   connect_success_continuation (proxied);
1654 }
1655
1656
1657 /* end of connection.c */