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      SPDX-License-Identifier: AGPL3.0-or-later
  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 #include "platform.h"
  34 #include "gnunet_util_lib.h"
  35 #include "gnunet_resolver_service.h"
  36
  37
  38 /**
  39  * Timeout we use on TCP connect before trying another
  40  * result from the DNS resolver.  Actual value used
  41  * is this value divided by the number of address families.
  42  * Default is 5s.
  43  */
  44 #define CONNECT_RETRY_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5)
  45
  46
  47
  48 #define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "util-connection", syscall)
  49
  50
  51 /**
  52  * Transmission handle.  There can only be one for each connection.
  53  */
  54 struct GNUNET_CONNECTION_TransmitHandle
  55 {
  56
  57   /**
  58    * Function to call if the send buffer has notify_size
  59    * bytes available.
  60    */
  61   GNUNET_CONNECTION_TransmitReadyNotify notify_ready;
  62
  63   /**
  64    * Closure for notify_ready.
  65    */
  66   void *notify_ready_cls;
  67
  68   /**
  69    * Our connection handle.
  70    */
  71   struct GNUNET_CONNECTION_Handle *connection;
  72
  73   /**
  74    * Timeout for receiving (in absolute time).
  75    */
  76   struct GNUNET_TIME_Absolute transmit_timeout;
  77
  78   /**
  79    * Task called on timeout.
  80    */
  81   struct GNUNET_SCHEDULER_Task * timeout_task;
  82
  83   /**
  84    * At what number of bytes available in the
  85    * write buffer should the notify method be called?
  86    */
  87   size_t notify_size;
  88
  89 };
  90
  91
  92 /**
  93  * During connect, we try multiple possible IP addresses
  94  * to find out which one might work.
  95  */
  96 struct AddressProbe
  97 {
  98
  99   /**
 100    * This is a linked list.
 101    */
 102   struct AddressProbe *next;
 103
 104   /**
 105    * This is a doubly-linked list.
 106    */
 107   struct AddressProbe *prev;
 108
 109   /**
 110    * The address; do not free (allocated at the end of this struct).
 111    */
 112   const struct sockaddr *addr;
 113
 114   /**
 115    * Underlying OS's socket.
 116    */
 117   struct GNUNET_NETWORK_Handle *sock;
 118
 119   /**
 120    * Connection for which we are probing.
 121    */
 122   struct GNUNET_CONNECTION_Handle *connection;
 123
 124   /**
 125    * Lenth of addr.
 126    */
 127   socklen_t addrlen;
 128
 129   /**
 130    * Task waiting for the connection to finish connecting.
 131    */
 132   struct GNUNET_SCHEDULER_Task * task;
 133 };
 134
 135
 136 /**
 137  * @brief handle for a network connection
 138  */
 139 struct GNUNET_CONNECTION_Handle
 140 {
 141
 142   /**
 143    * Configuration to use.
 144    */
 145   const struct GNUNET_CONFIGURATION_Handle *cfg;
 146
 147   /**
 148    * Linked list of sockets we are currently trying out
 149    * (during connect).
 150    */
 151   struct AddressProbe *ap_head;
 152
 153   /**
 154    * Linked list of sockets we are currently trying out
 155    * (during connect).
 156    */
 157   struct AddressProbe *ap_tail;
 158
 159   /**
 160    * Network address of the other end-point, may be NULL.
 161    */
 162   struct sockaddr *addr;
 163
 164   /**
 165    * Pointer to the hostname if connection was
 166    * created using DNS lookup, otherwise NULL.
 167    */
 168   char *hostname;
 169
 170   /**
 171    * Underlying OS's socket, set to NULL after fatal errors.
 172    */
 173   struct GNUNET_NETWORK_Handle *sock;
 174
 175   /**
 176    * Function to call on data received, NULL if no receive is pending.
 177    */
 178   GNUNET_CONNECTION_Receiver receiver;
 179
 180   /**
 181    * Closure for @e receiver.
 182    */
 183   void *receiver_cls;
 184
 185   /**
 186    * Pointer to our write buffer.
 187    */
 188   char *write_buffer;
 189
 190   /**
 191    * Current size of our @e write_buffer.
 192    */
 193   size_t write_buffer_size;
 194
 195   /**
 196    * Current write-offset in @e write_buffer (where
 197    * would we write next).
 198    */
 199   size_t write_buffer_off;
 200
 201   /**
 202    * Current read-offset in @e write_buffer (how many
 203    * bytes have already been sent).
 204    */
 205   size_t write_buffer_pos;
 206
 207   /**
 208    * Length of @e addr.
 209    */
 210   socklen_t addrlen;
 211
 212   /**
 213    * Read task that we may need to wait for.
 214    */
 215   struct GNUNET_SCHEDULER_Task *read_task;
 216
 217   /**
 218    * Write task that we may need to wait for.
 219    */
 220   struct GNUNET_SCHEDULER_Task *write_task;
 221
 222   /**
 223    * Handle to a pending DNS lookup request.
 224    */
 225   struct GNUNET_RESOLVER_RequestHandle *dns_active;
 226
 227   /**
 228    * The handle we return for #GNUNET_CONNECTION_notify_transmit_ready().
 229    */
 230   struct GNUNET_CONNECTION_TransmitHandle nth;
 231
 232   /**
 233    * Timeout for receiving (in absolute time).
 234    */
 235   struct GNUNET_TIME_Absolute receive_timeout;
 236
 237   /**
 238    * Maximum number of bytes to read (for receiving).
 239    */
 240   size_t max;
 241
 242   /**
 243    * Port to connect to.
 244    */
 245   uint16_t port;
 246
 247   /**
 248    * When shutdown, do not ever actually close the socket, but
 249    * free resources.  Only should ever be set if using program
 250    * termination as a signal (because only then will the leaked
 251    * socket be freed!)
 252    */
 253   int8_t persist;
 254
 255   /**
 256    * Usually 0.  Set to 1 if this handle is in use, and should
 257    * #GNUNET_CONNECTION_destroy() be called right now, the action needs
 258    * to be deferred by setting it to -1.
 259    */
 260   int8_t destroy_later;
 261
 262   /**
 263    * Handle to subsequent connection after proxy handshake completes,
 264    */
 265   struct GNUNET_CONNECTION_Handle *proxy_handshake;
 266
 267 };
 268
 269
 270 /**
 271  * Set the persist option on this connection handle.  Indicates
 272  * that the underlying socket or fd should never really be closed.
 273  * Used for indicating process death.
 274  *
 275  * @param connection the connection to set persistent
 276  */
 277 void
 278 GNUNET_CONNECTION_persist_ (struct GNUNET_CONNECTION_Handle *connection)
 279 {
 280   connection->persist = GNUNET_YES;
 281 }
 282
 283
 284 /**
 285  * Disable the "CORK" feature for communication with the given connection,
 286  * forcing the OS to immediately flush the buffer on transmission
 287  * instead of potentially buffering multiple messages.  Essentially
 288  * reduces the OS send buffers to zero.
 289  * Used to make sure that the last messages sent through the connection
 290  * reach the other side before the process is terminated.
 291  *
 292  * @param connection the connection to make flushing and blocking
 293  * @return #GNUNET_OK on success
 294  */
 295 int
 296 GNUNET_CONNECTION_disable_corking (struct GNUNET_CONNECTION_Handle *connection)
 297 {
 298   return GNUNET_NETWORK_socket_disable_corking (connection->sock);
 299 }
 300
 301
 302 /**
 303  * Create a connection handle by boxing an existing OS socket.  The OS
 304  * socket should henceforth be no longer used directly.
 305  * #GNUNET_connection_destroy() will close it.
 306  *
 307  * @param osSocket existing socket to box
 308  * @return the boxed connection handle
 309  */
 310 struct GNUNET_CONNECTION_Handle *
 311 GNUNET_CONNECTION_create_from_existing (struct GNUNET_NETWORK_Handle *osSocket)
 312 {
 313   struct GNUNET_CONNECTION_Handle *connection;
 314
 315   connection = GNUNET_new (struct GNUNET_CONNECTION_Handle);
 316   connection->write_buffer_size = GNUNET_MIN_MESSAGE_SIZE;
 317   connection->write_buffer = GNUNET_malloc (connection->write_buffer_size);
 318   connection->sock = osSocket;
 319   return connection;
 320 }
 321
 322
 323 /**
 324  * Create a connection handle by accepting on a listen socket.  This
 325  * function may block if the listen socket has no connection ready.
 326  *
 327  * @param access_cb function to use to check if access is allowed
 328  * @param access_cb_cls closure for @a access_cb
 329  * @param lsock listen socket
 330  * @return the connection handle, NULL on error
 331  */
 332 struct GNUNET_CONNECTION_Handle *
 333 GNUNET_CONNECTION_create_from_accept (GNUNET_CONNECTION_AccessCheck access_cb,
 334                                       void *access_cb_cls,
 335                                       struct GNUNET_NETWORK_Handle *lsock)
 336 {
 337   struct GNUNET_CONNECTION_Handle *connection;
 338   char addr[128];
 339   socklen_t addrlen;
 340   struct GNUNET_NETWORK_Handle *sock;
 341   int aret;
 342   struct sockaddr_in *v4;
 343   struct sockaddr_in6 *v6;
 344   struct sockaddr *sa;
 345   void *uaddr;
 346 #ifdef SO_PEERCRED
 347   struct ucred uc;
 348   socklen_t olen;
 349 #endif
 350   struct GNUNET_CONNECTION_Credentials *gcp;
 351 #if HAVE_GETPEEREID || defined(SO_PEERCRED) || HAVE_GETPEERUCRED
 352   struct GNUNET_CONNECTION_Credentials gc;
 353
 354   gc.uid = 0;
 355   gc.gid = 0;
 356 #endif
 357
 358   addrlen = sizeof (addr);
 359   sock =
 360       GNUNET_NETWORK_socket_accept (lsock,
 361                                     (struct sockaddr *) &addr,
 362                                     &addrlen);
 363   if (NULL == sock)
 364   {
 365     if (EAGAIN != errno)
 366       LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "accept");
 367     return NULL;
 368   }
 369   if ((addrlen > sizeof (addr)) || (addrlen < sizeof (sa_family_t)))
 370   {
 371     GNUNET_break (0);
 372     GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (sock));
 373     return NULL;
 374   }
 375
 376   sa = (struct sockaddr *) addr;
 377   v6 = (struct sockaddr_in6 *) addr;
 378   if ( (AF_INET6 == sa->sa_family) &&
 379        (IN6_IS_ADDR_V4MAPPED (&v6->sin6_addr)) )
 380   {
 381     /* convert to V4 address */
 382     v4 = GNUNET_new (struct sockaddr_in);
 383     memset (v4, 0, sizeof (struct sockaddr_in));
 384     v4->sin_family = AF_INET;
 385 #if HAVE_SOCKADDR_IN_SIN_LEN
 386     v4->sin_len = (u_char) sizeof (struct sockaddr_in);
 387 #endif
 388     GNUNET_memcpy (&v4->sin_addr,
 389             &((char *) &v6->sin6_addr)[sizeof (struct in6_addr) -
 390                                        sizeof (struct in_addr)],
 391             sizeof (struct in_addr));
 392     v4->sin_port = v6->sin6_port;
 393     uaddr = v4;
 394     addrlen = sizeof (struct sockaddr_in);
 395   }
 396   else
 397   {
 398     uaddr = GNUNET_malloc (addrlen);
 399     GNUNET_memcpy (uaddr, addr, addrlen);
 400   }
 401   gcp = NULL;
 402   if (AF_UNIX == sa->sa_family)
 403   {
 404 #if HAVE_GETPEEREID
 405     /* most BSDs */
 406     if (0 == getpeereid (GNUNET_NETWORK_get_fd (sock),
 407                          &gc.uid,
 408                          &gc.gid))
 409       gcp = &gc;
 410 #else
 411 #ifdef SO_PEERCRED
 412     /* largely traditional GNU/Linux */
 413     olen = sizeof (uc);
 414     if ( (0 ==
 415           getsockopt (GNUNET_NETWORK_get_fd (sock),
 416                       SOL_SOCKET,
 417                       SO_PEERCRED,
 418                       &uc,
 419                       &olen)) &&
 420          (olen == sizeof (uc)) )
 421     {
 422       gc.uid = uc.uid;
 423       gc.gid = uc.gid;
 424       gcp = &gc;
 425     }
 426 #else
 427 #if HAVE_GETPEERUCRED
 428     /* this is for Solaris 10 */
 429     ucred_t *uc;
 430
 431     uc = NULL;
 432     if (0 == getpeerucred (GNUNET_NETWORK_get_fd (sock), &uc))
 433     {
 434       gc.uid = ucred_geteuid (uc);
 435       gc.gid = ucred_getegid (uc);
 436       gcp = &gc;
 437     }
 438     ucred_free (uc);
 439 #endif
 440 #endif
 441 #endif
 442   }
 443
 444   if ( (NULL != access_cb) &&
 445        (GNUNET_YES != (aret = access_cb (access_cb_cls,
 446                                          gcp,
 447                                          uaddr,
 448                                          addrlen))) )
 449   {
 450     if (GNUNET_NO == aret)
 451       LOG (GNUNET_ERROR_TYPE_INFO,
 452            _("Access denied to `%s'\n"),
 453            GNUNET_a2s (uaddr,
 454                        addrlen));
 455     GNUNET_break (GNUNET_OK ==
 456                   GNUNET_NETWORK_socket_shutdown (sock,
 457                                                   SHUT_RDWR));
 458     GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (sock));
 459     GNUNET_free (uaddr);
 460     return NULL;
 461   }
 462   connection = GNUNET_new (struct GNUNET_CONNECTION_Handle);
 463   connection->write_buffer_size = GNUNET_MIN_MESSAGE_SIZE;
 464   connection->write_buffer = GNUNET_malloc (connection->write_buffer_size);
 465   connection->addr = uaddr;
 466   connection->addrlen = addrlen;
 467   connection->sock = sock;
 468   LOG (GNUNET_ERROR_TYPE_INFO,
 469        _("Accepting connection from `%s': %p\n"),
 470        GNUNET_a2s (uaddr,
 471                    addrlen),
 472        connection);
 473   return connection;
 474 }
 475
 476
 477 /**
 478  * Obtain the network address of the other party.
 479  *
 480  * @param connection the client to get the address for
 481  * @param addr where to store the address
 482  * @param addrlen where to store the length of the @a addr
 483  * @return #GNUNET_OK on success
 484  */
 485 int
 486 GNUNET_CONNECTION_get_address (struct GNUNET_CONNECTION_Handle *connection,
 487                                void **addr,
 488                                size_t *addrlen)
 489 {
 490   if ((NULL == connection->addr) || (0 == connection->addrlen))
 491     return GNUNET_NO;
 492   *addr = GNUNET_malloc (connection->addrlen);
 493   GNUNET_memcpy (*addr, connection->addr, connection->addrlen);
 494   *addrlen = connection->addrlen;
 495   return GNUNET_OK;
 496 }
 497
 498
 499 /**
 500  * Tell the receiver callback that we had an IO error.
 501  *
 502  * @param connection connection to signal error
 503  * @param errcode error code to send
 504  */
 505 static void
 506 signal_receive_error (struct GNUNET_CONNECTION_Handle *connection,
 507                       int errcode)
 508 {
 509   GNUNET_CONNECTION_Receiver receiver;
 510
 511   LOG (GNUNET_ERROR_TYPE_DEBUG,
 512        "Receive encounters error (%s), connection closed (%p)\n",
 513        STRERROR (errcode),
 514        connection);
 515   GNUNET_assert (NULL != (receiver = connection->receiver));
 516   connection->receiver = NULL;
 517   receiver (connection->receiver_cls,
 518             NULL,
 519             0,
 520             connection->addr,
 521             connection->addrlen,
 522             errcode);
 523 }
 524
 525
 526 /**
 527  * Tell the receiver callback that a timeout was reached.
 528  *
 529  * @param connection connection to signal for
 530  */
 531 static void
 532 signal_receive_timeout (struct GNUNET_CONNECTION_Handle *connection)
 533 {
 534   GNUNET_CONNECTION_Receiver receiver;
 535
 536   LOG (GNUNET_ERROR_TYPE_DEBUG,
 537        "Connection signals timeout to receiver (%p)!\n",
 538        connection);
 539   GNUNET_assert (NULL != (receiver = connection->receiver));
 540   connection->receiver = NULL;
 541   receiver (connection->receiver_cls, NULL, 0, NULL, 0, 0);
 542 }
 543
 544
 545 /**
 546  * We failed to transmit data to the service, signal the error.
 547  *
 548  * @param connection handle that had trouble
 549  * @param ecode error code (errno)
 550  */
 551 static void
 552 signal_transmit_error (struct GNUNET_CONNECTION_Handle *connection,
 553                        int ecode)
 554 {
 555   GNUNET_CONNECTION_TransmitReadyNotify notify;
 556
 557   LOG (GNUNET_ERROR_TYPE_DEBUG,
 558        "Transmission encounterd error (%s), connection closed (%p)\n",
 559        STRERROR (ecode),
 560        connection);
 561   if (NULL != connection->sock)
 562   {
 563     (void) GNUNET_NETWORK_socket_shutdown (connection->sock,
 564                                            SHUT_RDWR);
 565     GNUNET_break (GNUNET_OK ==
 566                   GNUNET_NETWORK_socket_close (connection->sock));
 567     connection->sock = NULL;
 568     GNUNET_assert (NULL == connection->write_task);
 569   }
 570   if (NULL != connection->read_task)
 571   {
 572     /* send errors trigger read errors... */
 573     GNUNET_SCHEDULER_cancel (connection->read_task);
 574     connection->read_task = NULL;
 575     signal_receive_timeout (connection);
 576     return;
 577   }
 578   if (NULL == connection->nth.notify_ready)
 579     return;                     /* nobody to tell about it */
 580   notify = connection->nth.notify_ready;
 581   connection->nth.notify_ready = NULL;
 582   notify (connection->nth.notify_ready_cls,
 583           0,
 584           NULL);
 585 }
 586
 587
 588 /**
 589  * We've failed for good to establish a connection (timeout or
 590  * no more addresses to try).
 591  *
 592  * @param connection the connection we tried to establish
 593  */
 594 static void
 595 connect_fail_continuation (struct GNUNET_CONNECTION_Handle *connection)
 596 {
 597   LOG (GNUNET_ERROR_TYPE_INFO,
 598        "Failed to establish TCP connection to `%s:%u', no further addresses to try.\n",
 599        connection->hostname,
 600     connection->port);
 601   GNUNET_break (NULL == connection->ap_head);
 602   GNUNET_break (NULL == connection->ap_tail);
 603   GNUNET_break (GNUNET_NO == connection->dns_active);
 604   GNUNET_break (NULL == connection->sock);
 605   GNUNET_assert (NULL == connection->write_task);
 606   GNUNET_assert (NULL == connection->proxy_handshake);
 607
 608   /* signal errors for jobs that used to wait on the connection */
 609   connection->destroy_later = 1;
 610   if (NULL != connection->receiver)
 611     signal_receive_error (connection,
 612                           ECONNREFUSED);
 613   if (NULL != connection->nth.notify_ready)
 614   {
 615     GNUNET_assert (NULL != connection->nth.timeout_task);
 616     GNUNET_SCHEDULER_cancel (connection->nth.timeout_task);
 617     connection->nth.timeout_task = NULL;
 618     signal_transmit_error (connection,
 619                            ECONNREFUSED);
 620   }
 621   if (-1 == connection->destroy_later)
 622   {
 623     /* do it now */
 624     connection->destroy_later = 0;
 625     GNUNET_CONNECTION_destroy (connection);
 626     return;
 627   }
 628   connection->destroy_later = 0;
 629 }
 630
 631
 632 /**
 633  * We are ready to transmit (or got a timeout).
 634  *
 635  * @param cls our connection handle
 636  */
 637 static void
 638 transmit_ready (void *cls);
 639
 640
 641 /**
 642  * This function is called once we either timeout or have data ready
 643  * to read.
 644  *
 645  * @param cls connection to read from
 646  */
 647 static void
 648 receive_ready (void *cls);
 649
 650
 651 /**
 652  * We've succeeded in establishing a connection.
 653  *
 654  * @param connection the connection we tried to establish
 655  */
 656 static void
 657 connect_success_continuation (struct GNUNET_CONNECTION_Handle *connection)
 658 {
 659   LOG (GNUNET_ERROR_TYPE_DEBUG,
 660        "Connection to `%s' succeeded! (%p)\n",
 661        GNUNET_a2s (connection->addr,
 662                    connection->addrlen),
 663        connection);
 664   /* trigger jobs that waited for the connection */
 665   if (NULL != connection->receiver)
 666   {
 667     LOG (GNUNET_ERROR_TYPE_DEBUG,
 668          "Connection succeeded, starting with receiving data (%p)\n",
 669          connection);
 670     GNUNET_assert (NULL == connection->read_task);
 671     connection->read_task =
 672       GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_absolute_get_remaining
 673                                      (connection->receive_timeout),
 674                                      connection->sock,
 675                                      &receive_ready, connection);
 676   }
 677   if (NULL != connection->nth.notify_ready)
 678   {
 679     LOG (GNUNET_ERROR_TYPE_DEBUG,
 680          "Connection succeeded, starting with sending data (%p)\n",
 681          connection);
 682     GNUNET_assert (connection->nth.timeout_task != NULL);
 683     GNUNET_SCHEDULER_cancel (connection->nth.timeout_task);
 684     connection->nth.timeout_task = NULL;
 685     GNUNET_assert (connection->write_task == NULL);
 686     connection->write_task =
 687         GNUNET_SCHEDULER_add_write_net (GNUNET_TIME_absolute_get_remaining
 688                                         (connection->nth.transmit_timeout), connection->sock,
 689                                         &transmit_ready, connection);
 690   }
 691 }
 692
 693
 694 /**
 695  * Scheduler let us know that we're either ready to write on the
 696  * socket OR connect timed out.  Do the right thing.
 697  *
 698  * @param cls the `struct AddressProbe *` with the address that we are probing
 699  */
 700 static void
 701 connect_probe_continuation (void *cls)
 702 {
 703   struct AddressProbe *ap = cls;
 704   struct GNUNET_CONNECTION_Handle *connection = ap->connection;
 705   const struct GNUNET_SCHEDULER_TaskContext *tc;
 706   struct AddressProbe *pos;
 707   int error;
 708   socklen_t len;
 709
 710   GNUNET_assert (NULL != ap->sock);
 711   GNUNET_CONTAINER_DLL_remove (connection->ap_head,
 712                                connection->ap_tail,
 713                                ap);
 714   len = sizeof (error);
 715   errno = 0;
 716   error = 0;
 717   tc = GNUNET_SCHEDULER_get_task_context ();
 718   if ( (0 == (tc->reason & GNUNET_SCHEDULER_REASON_WRITE_READY)) ||
 719        (GNUNET_OK !=
 720         GNUNET_NETWORK_socket_getsockopt (ap->sock,
 721                                           SOL_SOCKET,
 722                                           SO_ERROR,
 723                                           &error,
 724                                           &len)) ||
 725        (0 != error) )
 726   {
 727     GNUNET_break (GNUNET_OK ==
 728                   GNUNET_NETWORK_socket_close (ap->sock));
 729     GNUNET_free (ap);
 730     if ( (NULL == connection->ap_head) &&
 731          (GNUNET_NO == connection->dns_active) &&
 732          (NULL == connection->proxy_handshake) )
 733       connect_fail_continuation (connection);
 734     return;
 735   }
 736   GNUNET_assert (NULL == connection->sock);
 737   connection->sock = ap->sock;
 738   GNUNET_assert (NULL == connection->addr);
 739   connection->addr = GNUNET_malloc (ap->addrlen);
 740   GNUNET_memcpy (connection->addr, ap->addr, ap->addrlen);
 741   connection->addrlen = ap->addrlen;
 742   GNUNET_free (ap);
 743   /* cancel all other attempts */
 744   while (NULL != (pos = connection->ap_head))
 745   {
 746     GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (pos->sock));
 747     GNUNET_SCHEDULER_cancel (pos->task);
 748     GNUNET_CONTAINER_DLL_remove (connection->ap_head,
 749                                  connection->ap_tail,
 750                                  pos);
 751     GNUNET_free (pos);
 752   }
 753   connect_success_continuation (connection);
 754 }
 755
 756
 757 /**
 758  * Try to establish a connection given the specified address.
 759  * This function is called by the resolver once we have a DNS reply.
 760  *
 761  * @param cls our `struct GNUNET_CONNECTION_Handle *`
 762  * @param addr address to try, NULL for "last call"
 763  * @param addrlen length of @a addr
 764  */
 765 static void
 766 try_connect_using_address (void *cls,
 767                            const struct sockaddr *addr,
 768                            socklen_t addrlen)
 769 {
 770   struct GNUNET_CONNECTION_Handle *connection = cls;
 771   struct AddressProbe *ap;
 772   struct GNUNET_TIME_Relative delay;
 773
 774   if (NULL == addr)
 775   {
 776     connection->dns_active = NULL;
 777     if ((NULL == connection->ap_head) &&
 778         (NULL == connection->sock) &&
 779         (NULL == connection->proxy_handshake))
 780       connect_fail_continuation (connection);
 781     return;
 782   }
 783   if (NULL != connection->sock)
 784     return;                     /* already connected */
 785   GNUNET_assert (NULL == connection->addr);
 786   /* try to connect */
 787   LOG (GNUNET_ERROR_TYPE_DEBUG,
 788        "Trying to connect using address `%s:%u/%s:%u'\n",
 789        connection->hostname,
 790        connection->port,
 791        GNUNET_a2s (addr, addrlen),
 792        connection->port);
 793   ap = GNUNET_malloc (sizeof (struct AddressProbe) + addrlen);
 794   ap->addr = (const struct sockaddr *) &ap[1];
 795   GNUNET_memcpy (&ap[1], addr, addrlen);
 796   ap->addrlen = addrlen;
 797   ap->connection = connection;
 798
 799   switch (ap->addr->sa_family)
 800   {
 801   case AF_INET:
 802     ((struct sockaddr_in *) ap->addr)->sin_port = htons (connection->port);
 803     break;
 804   case AF_INET6:
 805     ((struct sockaddr_in6 *) ap->addr)->sin6_port = htons (connection->port);
 806     break;
 807   default:
 808     GNUNET_break (0);
 809     GNUNET_free (ap);
 810     return;                     /* not supported by us */
 811   }
 812   ap->sock = GNUNET_NETWORK_socket_create (ap->addr->sa_family,
 813                                            SOCK_STREAM, 0);
 814   if (NULL == ap->sock)
 815   {
 816     GNUNET_free (ap);
 817     return;                     /* not supported by OS */
 818   }
 819   LOG (GNUNET_ERROR_TYPE_INFO,
 820        "Trying to connect to `%s' (%p)\n",
 821        GNUNET_a2s (ap->addr, ap->addrlen),
 822        connection);
 823   if ((GNUNET_OK !=
 824        GNUNET_NETWORK_socket_connect (ap->sock,
 825                                       ap->addr,
 826                                       ap->addrlen)) &&
 827       (EINPROGRESS != errno))
 828   {
 829     /* maybe refused / unsupported address, try next */
 830     LOG_STRERROR (GNUNET_ERROR_TYPE_INFO, "connect");
 831     GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (ap->sock));
 832     GNUNET_free (ap);
 833     return;
 834   }
 835   GNUNET_CONTAINER_DLL_insert (connection->ap_head, connection->ap_tail, ap);
 836   delay = CONNECT_RETRY_TIMEOUT;
 837   if (NULL != connection->nth.notify_ready)
 838     delay = GNUNET_TIME_relative_min (delay,
 839                                       GNUNET_TIME_absolute_get_remaining (connection->nth.transmit_timeout));
 840   if (NULL != connection->receiver)
 841     delay = GNUNET_TIME_relative_min (delay,
 842                                       GNUNET_TIME_absolute_get_remaining (connection->receive_timeout));
 843   ap->task = GNUNET_SCHEDULER_add_write_net (delay,
 844                                              ap->sock,
 845                                              &connect_probe_continuation,
 846                                              ap);
 847 }
 848
 849
 850 /**
 851  * Create a connection 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 cfg configuration to use
 856  * @param hostname name of the host to connect to
 857  * @param port port to connect to
 858  * @return the connection handle
 859  */
 860 struct GNUNET_CONNECTION_Handle *
 861 GNUNET_CONNECTION_create_from_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
 862                                        const char *hostname,
 863                                        uint16_t port)
 864 {
 865   struct GNUNET_CONNECTION_Handle *connection;
 866
 867   GNUNET_assert (0 < strlen (hostname));        /* sanity check */
 868   connection = GNUNET_new (struct GNUNET_CONNECTION_Handle);
 869   connection->cfg = cfg;
 870   connection->write_buffer_size = GNUNET_MIN_MESSAGE_SIZE;
 871   connection->write_buffer = GNUNET_malloc (connection->write_buffer_size);
 872   connection->port = port;
 873   connection->hostname = GNUNET_strdup (hostname);
 874   connection->dns_active =
 875       GNUNET_RESOLVER_ip_get (connection->hostname,
 876                               AF_UNSPEC,
 877                               CONNECT_RETRY_TIMEOUT,
 878                               &try_connect_using_address,
 879                               connection);
 880   return connection;
 881 }
 882
 883
 884 /**
 885  * Create a connection handle by connecting to a UNIX domain service.
 886  * This function returns immediately, even if the connection has not
 887  * yet been established.  This function only creates UNIX connections.
 888  *
 889  * @param cfg configuration to use
 890  * @param unixpath path to connect to
 891  * @return the connection handle, NULL on systems without UNIX support
 892  */
 893 struct GNUNET_CONNECTION_Handle *
 894 GNUNET_CONNECTION_create_from_connect_to_unixpath (const struct GNUNET_CONFIGURATION_Handle *cfg,
 895                                                    const char *unixpath)
 896 {
 897 #ifdef AF_UNIX
 898   struct GNUNET_CONNECTION_Handle *connection;
 899   struct sockaddr_un *un;
 900
 901   GNUNET_assert (0 < strlen (unixpath));        /* sanity check */
 902   un = GNUNET_new (struct sockaddr_un);
 903   un->sun_family = AF_UNIX;
 904   strncpy (un->sun_path, unixpath, sizeof (un->sun_path) - 1);
 905 #ifdef LINUX
 906   {
 907     int abstract;
 908
 909     abstract = GNUNET_CONFIGURATION_get_value_yesno (cfg,
 910                                                      "TESTING",
 911                                                      "USE_ABSTRACT_SOCKETS");
 912     if (GNUNET_YES == abstract)
 913       un->sun_path[0] = '\0';
 914   }
 915 #endif
 916 #if HAVE_SOCKADDR_UN_SUN_LEN
 917   un->sun_len = (u_char) sizeof (struct sockaddr_un);
 918 #endif
 919   connection = GNUNET_new (struct GNUNET_CONNECTION_Handle);
 920   connection->cfg = cfg;
 921   connection->write_buffer_size = GNUNET_MIN_MESSAGE_SIZE;
 922   connection->write_buffer = GNUNET_malloc (connection->write_buffer_size);
 923   connection->port = 0;
 924   connection->hostname = NULL;
 925   connection->addr = (struct sockaddr *) un;
 926   connection->addrlen = sizeof (struct sockaddr_un);
 927   connection->sock = GNUNET_NETWORK_socket_create (AF_UNIX,
 928                                                    SOCK_STREAM,
 929                                                    0);
 930   if (NULL == connection->sock)
 931   {
 932     GNUNET_free (connection->addr);
 933     GNUNET_free (connection->write_buffer);
 934     GNUNET_free (connection);
 935     return NULL;
 936   }
 937   if ( (GNUNET_OK !=
 938         GNUNET_NETWORK_socket_connect (connection->sock,
 939                                        connection->addr,
 940                                        connection->addrlen)) &&
 941        (EINPROGRESS != errno) )
 942   {
 943     /* Just return; we expect everything to work eventually so don't fail HARD */
 944     GNUNET_break (GNUNET_OK ==
 945                   GNUNET_NETWORK_socket_close (connection->sock));
 946     connection->sock = NULL;
 947     return connection;
 948   }
 949   connect_success_continuation (connection);
 950   return connection;
 951 #else
 952   return NULL;
 953 #endif
 954 }
 955
 956
 957 /**
 958  * Create a connection handle by (asynchronously) connecting to a host.
 959  * This function returns immediately, even if the connection has not
 960  * yet been established.  This function only creates TCP connections.
 961  *
 962  * @param s socket to connect
 963  * @param serv_addr server address
 964  * @param addrlen length of @a serv_addr
 965  * @return the connection handle
 966  */
 967 struct GNUNET_CONNECTION_Handle *
 968 GNUNET_CONNECTION_connect_socket (struct GNUNET_NETWORK_Handle *s,
 969                                   const struct sockaddr *serv_addr,
 970                                   socklen_t addrlen)
 971 {
 972   struct GNUNET_CONNECTION_Handle *connection;
 973
 974   if ( (GNUNET_OK !=
 975         GNUNET_NETWORK_socket_connect (s, serv_addr, addrlen)) &&
 976        (EINPROGRESS != errno) )
 977   {
 978     /* maybe refused / unsupported address, try next */
 979     LOG_STRERROR (GNUNET_ERROR_TYPE_DEBUG,
 980                   "connect");
 981     LOG (GNUNET_ERROR_TYPE_DEBUG,
 982          "Attempt to connect to `%s' failed\n",
 983          GNUNET_a2s (serv_addr,
 984                      addrlen));
 985     GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (s));
 986     return NULL;
 987   }
 988   connection = GNUNET_CONNECTION_create_from_existing (s);
 989   connection->addr = GNUNET_malloc (addrlen);
 990   GNUNET_memcpy (connection->addr, serv_addr, addrlen);
 991   connection->addrlen = addrlen;
 992   LOG (GNUNET_ERROR_TYPE_INFO,
 993        "Trying to connect to `%s' (%p)\n",
 994        GNUNET_a2s (serv_addr, addrlen),
 995        connection);
 996   return connection;
 997 }
 998
 999
1000 /**
1001  * Create a connection handle by creating a socket and
1002  * (asynchronously) connecting to a host.  This function returns
1003  * immediately, even if the connection has not yet been established.
1004  * This function only creates TCP connections.
1005  *
1006  * @param af_family address family to use
1007  * @param serv_addr server address
1008  * @param addrlen length of @a serv_addr
1009  * @return the connection handle
1010  */
1011 struct GNUNET_CONNECTION_Handle *
1012 GNUNET_CONNECTION_create_from_sockaddr (int af_family,
1013                                         const struct sockaddr *serv_addr,
1014                                         socklen_t addrlen)
1015 {
1016   struct GNUNET_NETWORK_Handle *s;
1017
1018   s = GNUNET_NETWORK_socket_create (af_family, SOCK_STREAM, 0);
1019   if (NULL == s)
1020   {
1021     LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING | GNUNET_ERROR_TYPE_BULK,
1022                   "socket");
1023     return NULL;
1024   }
1025   return GNUNET_CONNECTION_connect_socket (s,
1026                                            serv_addr,
1027                                            addrlen);
1028 }
1029
1030
1031 /**
1032  * Check if connection is valid (no fatal errors have happened so far).
1033  * Note that a connection that is still trying to connect is considered
1034  * valid.
1035  *
1036  * @param connection connection to check
1037  * @return #GNUNET_YES if valid, #GNUNET_NO otherwise
1038  */
1039 int
1040 GNUNET_CONNECTION_check (struct GNUNET_CONNECTION_Handle *connection)
1041 {
1042   if ((NULL != connection->ap_head) ||
1043       (NULL != connection->dns_active) ||
1044       (NULL != connection->proxy_handshake))
1045     return GNUNET_YES;          /* still trying to connect */
1046   if ( (0 != connection->destroy_later) ||
1047        (NULL == connection->sock) )
1048     return GNUNET_NO;
1049   return GNUNET_YES;
1050 }
1051
1052
1053 /**
1054  * Close the connection and free associated resources.  There must
1055  * not be any pending requests for reading or writing to the
1056  * connection at this time.
1057  *
1058  * @param connection connection to destroy
1059  */
1060 void
1061 GNUNET_CONNECTION_destroy (struct GNUNET_CONNECTION_Handle *connection)
1062 {
1063   struct AddressProbe *pos;
1064
1065   if (0 != connection->destroy_later)
1066   {
1067     connection->destroy_later = -1;
1068     return;
1069   }
1070   LOG (GNUNET_ERROR_TYPE_DEBUG,
1071        "Shutting down connection (%p)\n",
1072        connection);
1073   GNUNET_assert (NULL == connection->nth.notify_ready);
1074   GNUNET_assert (NULL == connection->receiver);
1075   if (NULL != connection->write_task)
1076   {
1077     GNUNET_SCHEDULER_cancel (connection->write_task);
1078     connection->write_task = NULL;
1079     connection->write_buffer_off = 0;
1080   }
1081   if (NULL != connection->read_task)
1082   {
1083     GNUNET_SCHEDULER_cancel (connection->read_task);
1084     connection->read_task = NULL;
1085   }
1086   if (NULL != connection->nth.timeout_task)
1087   {
1088     GNUNET_SCHEDULER_cancel (connection->nth.timeout_task);
1089     connection->nth.timeout_task = NULL;
1090   }
1091   connection->nth.notify_ready = NULL;
1092   if (NULL != connection->dns_active)
1093   {
1094     GNUNET_RESOLVER_request_cancel (connection->dns_active);
1095     connection->dns_active = NULL;
1096   }
1097   if (NULL != connection->proxy_handshake)
1098   {
1099     /* GNUNET_CONNECTION_destroy (connection->proxy_handshake); */
1100     connection->proxy_handshake->destroy_later = -1;
1101     connection->proxy_handshake = NULL;  /* Not leaked ??? */
1102   }
1103   while (NULL != (pos = connection->ap_head))
1104   {
1105     GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (pos->sock));
1106     GNUNET_SCHEDULER_cancel (pos->task);
1107     GNUNET_CONTAINER_DLL_remove (connection->ap_head,
1108                                  connection->ap_tail,
1109                                  pos);
1110     GNUNET_free (pos);
1111   }
1112   if ( (NULL != connection->sock) &&
1113        (GNUNET_YES != connection->persist) )
1114   {
1115     if ((GNUNET_OK !=
1116          GNUNET_NETWORK_socket_shutdown (connection->sock,
1117                                          SHUT_RDWR)) &&
1118         (ENOTCONN != errno) &&
1119         (ECONNRESET != errno) )
1120       LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING,
1121                     "shutdown");
1122   }
1123   if (NULL != connection->sock)
1124   {
1125     if (GNUNET_YES != connection->persist)
1126     {
1127       GNUNET_break (GNUNET_OK ==
1128                     GNUNET_NETWORK_socket_close (connection->sock));
1129     }
1130     else
1131     {
1132       GNUNET_NETWORK_socket_free_memory_only_ (connection->sock); /* at least no memory leak (we deliberately
1133                                                                    * leak the socket in this special case) ... */
1134     }
1135   }
1136   GNUNET_free_non_null (connection->addr);
1137   GNUNET_free_non_null (connection->hostname);
1138   GNUNET_free (connection->write_buffer);
1139   GNUNET_free (connection);
1140 }
1141
1142
1143 /**
1144  * This function is called once we either timeout
1145  * or have data ready to read.
1146  *
1147  * @param cls connection to read from
1148  */
1149 static void
1150 receive_ready (void *cls)
1151 {
1152   struct GNUNET_CONNECTION_Handle *connection = cls;
1153   const struct GNUNET_SCHEDULER_TaskContext *tc;
1154   char buffer[connection->max];
1155   ssize_t ret;
1156   GNUNET_CONNECTION_Receiver receiver;
1157
1158   connection->read_task = NULL;
1159   tc = GNUNET_SCHEDULER_get_task_context ();
1160   if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_TIMEOUT))
1161   {
1162     LOG (GNUNET_ERROR_TYPE_DEBUG,
1163          "Receive from `%s' encounters error: timeout (%s, %p)\n",
1164          GNUNET_a2s (connection->addr,
1165                      connection->addrlen),
1166          GNUNET_STRINGS_relative_time_to_string (GNUNET_TIME_absolute_get_duration (connection->receive_timeout),
1167                                                  GNUNET_YES),
1168          connection);
1169     signal_receive_timeout (connection);
1170     return;
1171   }
1172   if (NULL == connection->sock)
1173   {
1174     /* connect failed for good */
1175     signal_receive_error (connection, ECONNREFUSED);
1176     return;
1177   }
1178   GNUNET_assert (GNUNET_NETWORK_fdset_isset (tc->read_ready,
1179                                              connection->sock));
1180 RETRY:
1181   ret = GNUNET_NETWORK_socket_recv (connection->sock,
1182                                     buffer,
1183                                     connection->max);
1184   if (-1 == ret)
1185   {
1186     if (EINTR == errno)
1187       goto RETRY;
1188     signal_receive_error (connection, errno);
1189     return;
1190   }
1191   LOG (GNUNET_ERROR_TYPE_DEBUG,
1192        "receive_ready read %u/%u bytes from `%s' (%p)!\n",
1193        (unsigned int) ret,
1194        connection->max,
1195        GNUNET_a2s (connection->addr,
1196                    connection->addrlen),
1197        connection);
1198   GNUNET_assert (NULL != (receiver = connection->receiver));
1199   connection->receiver = NULL;
1200   receiver (connection->receiver_cls,
1201             buffer,
1202             ret,
1203             connection->addr,
1204             connection->addrlen,
1205             0);
1206 }
1207
1208
1209 /**
1210  * Receive data from the given connection.  Note that this function
1211  * will call @a receiver asynchronously using the scheduler.  It will
1212  * "immediately" return.  Note that there MUST only be one active
1213  * receive call per connection at any given point in time (so do not
1214  * call receive again until the receiver callback has been invoked).
1215  *
1216  * @param connection connection handle
1217  * @param max maximum number of bytes to read
1218  * @param timeout maximum amount of time to wait
1219  * @param receiver function to call with received data
1220  * @param receiver_cls closure for @a receiver
1221  * @return #GNUNET_SYSERR if @a connection died (receiver was
1222  *          called with error)
1223  */
1224 int
1225 GNUNET_CONNECTION_receive (struct GNUNET_CONNECTION_Handle *connection,
1226                            size_t max,
1227                            struct GNUNET_TIME_Relative timeout,
1228                            GNUNET_CONNECTION_Receiver receiver,
1229                            void *receiver_cls)
1230 {
1231   GNUNET_assert ((NULL == connection->read_task) &&
1232                  (NULL == connection->receiver));
1233   GNUNET_assert (NULL != receiver);
1234   connection->receiver = receiver;
1235   connection->receiver_cls = receiver_cls;
1236   connection->receive_timeout = GNUNET_TIME_relative_to_absolute (timeout);
1237   connection->max = max;
1238   if (NULL != connection->sock)
1239   {
1240     connection->read_task =
1241       GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_absolute_get_remaining
1242                                      (connection->receive_timeout),
1243                                      connection->sock,
1244                                      &receive_ready,
1245                                      connection);
1246     return GNUNET_OK;
1247   }
1248   if ((NULL == connection->dns_active) &&
1249       (NULL == connection->ap_head) &&
1250       (NULL == connection->proxy_handshake))
1251   {
1252     connection->receiver = NULL;
1253     receiver (receiver_cls,
1254               NULL, 0,
1255               NULL, 0,
1256               ETIMEDOUT);
1257     return GNUNET_SYSERR;
1258   }
1259   return GNUNET_OK;
1260 }
1261
1262
1263 /**
1264  * Cancel receive job on the given connection.  Note that the
1265  * receiver callback must not have been called yet in order
1266  * for the cancellation to be valid.
1267  *
1268  * @param connection connection handle
1269  * @return closure of the original receiver callback closure
1270  */
1271 void *
1272 GNUNET_CONNECTION_receive_cancel (struct GNUNET_CONNECTION_Handle *connection)
1273 {
1274   if (NULL != connection->read_task)
1275   {
1276     GNUNET_assert (connection ==
1277                    GNUNET_SCHEDULER_cancel (connection->read_task));
1278     connection->read_task = NULL;
1279   }
1280   connection->receiver = NULL;
1281   return connection->receiver_cls;
1282 }
1283
1284
1285 /**
1286  * Try to call the transmit notify method (check if we do
1287  * have enough space available first)!
1288  *
1289  * @param connection connection for which we should do this processing
1290  * @return #GNUNET_YES if we were able to call notify
1291  */
1292 static int
1293 process_notify (struct GNUNET_CONNECTION_Handle *connection)
1294 {
1295   size_t used;
1296   size_t avail;
1297   size_t size;
1298   GNUNET_CONNECTION_TransmitReadyNotify notify;
1299
1300   LOG (GNUNET_ERROR_TYPE_DEBUG,
1301        "process_notify is running\n");
1302   GNUNET_assert (NULL == connection->write_task);
1303   if (NULL == (notify = connection->nth.notify_ready))
1304   {
1305     LOG (GNUNET_ERROR_TYPE_DEBUG,
1306          "No one to notify\n");
1307     return GNUNET_NO;
1308   }
1309   used = connection->write_buffer_off - connection->write_buffer_pos;
1310   avail = connection->write_buffer_size - used;
1311   size = connection->nth.notify_size;
1312   if (size > avail)
1313   {
1314     LOG (GNUNET_ERROR_TYPE_DEBUG,
1315          "Not enough buffer\n");
1316     return GNUNET_NO;
1317   }
1318   connection->nth.notify_ready = NULL;
1319   if (connection->write_buffer_size - connection->write_buffer_off < size)
1320   {
1321     /* need to compact */
1322     memmove (connection->write_buffer,
1323              &connection->write_buffer[connection->write_buffer_pos],
1324              used);
1325     connection->write_buffer_off -= connection->write_buffer_pos;
1326     connection->write_buffer_pos = 0;
1327   }
1328   avail = connection->write_buffer_size - connection->write_buffer_off;
1329   GNUNET_assert (avail >= size);
1330   size =
1331       notify (connection->nth.notify_ready_cls, avail,
1332               &connection->write_buffer[connection->write_buffer_off]);
1333   GNUNET_assert (size <= avail);
1334   if (0 != size)
1335     connection->write_buffer_off += size;
1336   return GNUNET_YES;
1337 }
1338
1339
1340 /**
1341  * Task invoked by the scheduler when a call to transmit
1342  * is timing out (we never got enough buffer space to call
1343  * the callback function before the specified timeout
1344  * expired).
1345  *
1346  * This task notifies the client about the timeout.
1347  *
1348  * @param cls the `struct GNUNET_CONNECTION_Handle`
1349  */
1350 static void
1351 transmit_timeout (void *cls)
1352 {
1353   struct GNUNET_CONNECTION_Handle *connection = cls;
1354   GNUNET_CONNECTION_TransmitReadyNotify notify;
1355
1356   connection->nth.timeout_task = NULL;
1357   LOG (GNUNET_ERROR_TYPE_DEBUG,
1358        "Transmit to `%s:%u/%s' fails, time out reached (%p).\n",
1359        connection->hostname,
1360        connection->port,
1361        GNUNET_a2s (connection->addr,
1362                    connection->addrlen),
1363        connection);
1364   notify = connection->nth.notify_ready;
1365   GNUNET_assert (NULL != notify);
1366   connection->nth.notify_ready = NULL;
1367   notify (connection->nth.notify_ready_cls,
1368           0,
1369           NULL);
1370 }
1371
1372
1373 /**
1374  * Task invoked by the scheduler when we failed to connect
1375  * at the time of being asked to transmit.
1376  *
1377  * This task notifies the client about the error.
1378  *
1379  * @param cls the `struct GNUNET_CONNECTION_Handle`
1380  */
1381 static void
1382 connect_error (void *cls)
1383 {
1384   struct GNUNET_CONNECTION_Handle *connection = cls;
1385   GNUNET_CONNECTION_TransmitReadyNotify notify;
1386
1387   LOG (GNUNET_ERROR_TYPE_DEBUG,
1388        "Transmission request of size %u fails (%s/%u), connection failed (%p).\n",
1389        connection->nth.notify_size,
1390        connection->hostname,
1391        connection->port,
1392        connection);
1393   connection->write_task = NULL;
1394   notify = connection->nth.notify_ready;
1395   connection->nth.notify_ready = NULL;
1396   notify (connection->nth.notify_ready_cls,
1397           0,
1398           NULL);
1399 }
1400
1401
1402 /**
1403  * We are ready to transmit (or got a timeout).
1404  *
1405  * @param cls our connection handle
1406  */
1407 static void
1408 transmit_ready (void *cls)
1409 {
1410   struct GNUNET_CONNECTION_Handle *connection = cls;
1411   GNUNET_CONNECTION_TransmitReadyNotify notify;
1412   const struct GNUNET_SCHEDULER_TaskContext *tc;
1413   ssize_t ret;
1414   size_t have;
1415
1416   LOG (GNUNET_ERROR_TYPE_DEBUG,
1417        "transmit_ready running (%p).\n",
1418        connection);
1419   GNUNET_assert (NULL != connection->write_task);
1420   connection->write_task = NULL;
1421   GNUNET_assert (NULL == connection->nth.timeout_task);
1422   tc = GNUNET_SCHEDULER_get_task_context ();
1423   if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_TIMEOUT))
1424   {
1425     LOG (GNUNET_ERROR_TYPE_DEBUG,
1426          "Transmit to `%s' fails, time out reached (%p).\n",
1427          GNUNET_a2s (connection->addr,
1428                      connection->addrlen),
1429          connection);
1430     notify = connection->nth.notify_ready;
1431     GNUNET_assert (NULL != notify);
1432     connection->nth.notify_ready = NULL;
1433     notify (connection->nth.notify_ready_cls, 0, NULL);
1434     return;
1435   }
1436   GNUNET_assert (NULL != connection->sock);
1437   if (NULL == tc->write_ready)
1438   {
1439     /* special circumstances (in particular, PREREQ_DONE after
1440      * connect): not yet ready to write, but no "fatal" error either.
1441      * Hence retry.  */
1442     goto SCHEDULE_WRITE;
1443   }
1444   if (! GNUNET_NETWORK_fdset_isset (tc->write_ready,
1445                                     connection->sock))
1446   {
1447     GNUNET_assert (NULL == connection->write_task);
1448     /* special circumstances (in particular, shutdown): not yet ready
1449      * to write, but no "fatal" error either.  Hence retry.  */
1450     goto SCHEDULE_WRITE;
1451   }
1452   GNUNET_assert (connection->write_buffer_off >= connection->write_buffer_pos);
1453   if ((NULL != connection->nth.notify_ready) &&
1454       (connection->write_buffer_size < connection->nth.notify_size))
1455   {
1456     connection->write_buffer =
1457         GNUNET_realloc (connection->write_buffer, connection->nth.notify_size);
1458     connection->write_buffer_size = connection->nth.notify_size;
1459   }
1460   process_notify (connection);
1461   have = connection->write_buffer_off - connection->write_buffer_pos;
1462   if (0 == have)
1463   {
1464     /* no data ready for writing, terminate write loop */
1465     return;
1466   }
1467   GNUNET_assert (have <= connection->write_buffer_size);
1468   GNUNET_assert (have + connection->write_buffer_pos <= connection->write_buffer_size);
1469   GNUNET_assert (connection->write_buffer_pos <= connection->write_buffer_size);
1470 RETRY:
1471   ret =
1472       GNUNET_NETWORK_socket_send (connection->sock,
1473                                   &connection->write_buffer[connection->write_buffer_pos],
1474                                   have);
1475   if (-1 == ret)
1476   {
1477     if (EINTR == errno)
1478       goto RETRY;
1479     if (NULL != connection->write_task)
1480     {
1481       GNUNET_SCHEDULER_cancel (connection->write_task);
1482       connection->write_task = NULL;
1483     }
1484     signal_transmit_error (connection, errno);
1485     return;
1486   }
1487   LOG (GNUNET_ERROR_TYPE_DEBUG,
1488        "Connection transmitted %u/%u bytes to `%s' (%p)\n",
1489        (unsigned int) ret,
1490        have,
1491        GNUNET_a2s (connection->addr,
1492                    connection->addrlen),
1493        connection);
1494   connection->write_buffer_pos += ret;
1495   if (connection->write_buffer_pos == connection->write_buffer_off)
1496   {
1497     /* transmitted all pending data */
1498     connection->write_buffer_pos = 0;
1499     connection->write_buffer_off = 0;
1500   }
1501   if ( (0 == connection->write_buffer_off) &&
1502        (NULL == connection->nth.notify_ready) )
1503     return;                     /* all data sent! */
1504   /* not done writing, schedule more */
1505 SCHEDULE_WRITE:
1506   LOG (GNUNET_ERROR_TYPE_DEBUG,
1507        "Re-scheduling transmit_ready (more to do) (%p).\n",
1508        connection);
1509   have = connection->write_buffer_off - connection->write_buffer_pos;
1510   GNUNET_assert ( (NULL != connection->nth.notify_ready) ||
1511                   (have > 0) );
1512   if (NULL == connection->write_task)
1513     connection->write_task =
1514         GNUNET_SCHEDULER_add_write_net ((connection->nth.notify_ready ==
1515                                          NULL) ? GNUNET_TIME_UNIT_FOREVER_REL :
1516                                         GNUNET_TIME_absolute_get_remaining
1517                                         (connection->nth.transmit_timeout),
1518                                         connection->sock,
1519                                         &transmit_ready, connection);
1520 }
1521
1522
1523 /**
1524  * Ask the connection to call us once the specified number of bytes
1525  * are free in the transmission buffer.  Will never call the @a notify
1526  * callback in this task, but always first go into the scheduler.
1527  *
1528  * @param connection connection
1529  * @param size number of bytes to send
1530  * @param timeout after how long should we give up (and call
1531  *        @a notify with buf NULL and size 0)?
1532  * @param notify function to call
1533  * @param notify_cls closure for @a notify
1534  * @return non-NULL if the notify callback was queued,
1535  *         NULL if we are already going to notify someone else (busy)
1536  */
1537 struct GNUNET_CONNECTION_TransmitHandle *
1538 GNUNET_CONNECTION_notify_transmit_ready (struct GNUNET_CONNECTION_Handle *connection,
1539                                          size_t size,
1540                                          struct GNUNET_TIME_Relative timeout,
1541                                          GNUNET_CONNECTION_TransmitReadyNotify notify,
1542                                          void *notify_cls)
1543 {
1544   if (NULL != connection->nth.notify_ready)
1545   {
1546     GNUNET_assert (0);
1547     return NULL;
1548   }
1549   GNUNET_assert (NULL != notify);
1550   GNUNET_assert (size < GNUNET_MAX_MESSAGE_SIZE);
1551   GNUNET_assert (connection->write_buffer_off <= connection->write_buffer_size);
1552   GNUNET_assert (connection->write_buffer_pos <= connection->write_buffer_size);
1553   GNUNET_assert (connection->write_buffer_pos <= connection->write_buffer_off);
1554   connection->nth.notify_ready = notify;
1555   connection->nth.notify_ready_cls = notify_cls;
1556   connection->nth.connection = connection;
1557   connection->nth.notify_size = size;
1558   connection->nth.transmit_timeout = GNUNET_TIME_relative_to_absolute (timeout);
1559   GNUNET_assert (NULL == connection->nth.timeout_task);
1560   if ((NULL == connection->sock) &&
1561       (NULL == connection->ap_head) &&
1562       (NULL == connection->dns_active) &&
1563       (NULL == connection->proxy_handshake))
1564   {
1565     if (NULL != connection->write_task)
1566       GNUNET_SCHEDULER_cancel (connection->write_task);
1567     connection->write_task = GNUNET_SCHEDULER_add_now (&connect_error,
1568                                                        connection);
1569     return &connection->nth;
1570   }
1571   if (NULL != connection->write_task)
1572     return &connection->nth; /* previous transmission still in progress */
1573   if (NULL != connection->sock)
1574   {
1575     /* connected, try to transmit now */
1576     LOG (GNUNET_ERROR_TYPE_DEBUG,
1577          "Scheduling transmission (%p).\n",
1578          connection);
1579     connection->write_task =
1580         GNUNET_SCHEDULER_add_write_net (GNUNET_TIME_absolute_get_remaining
1581                                         (connection->nth.transmit_timeout),
1582                                         connection->sock,
1583                                         &transmit_ready, connection);
1584     return &connection->nth;
1585   }
1586   /* not yet connected, wait for connection */
1587   LOG (GNUNET_ERROR_TYPE_DEBUG,
1588        "Need to wait to schedule transmission for connection, adding timeout task (%p).\n",
1589        connection);
1590   connection->nth.timeout_task =
1591     GNUNET_SCHEDULER_add_delayed (timeout,
1592                                   &transmit_timeout,
1593                                   connection);
1594   return &connection->nth;
1595 }
1596
1597
1598 /**
1599  * Cancel the specified transmission-ready notification.
1600  *
1601  * @param th notification to cancel
1602  */
1603 void
1604 GNUNET_CONNECTION_notify_transmit_ready_cancel (struct GNUNET_CONNECTION_TransmitHandle *th)
1605 {
1606   GNUNET_assert (NULL != th->notify_ready);
1607   th->notify_ready = NULL;
1608   if (NULL != th->timeout_task)
1609   {
1610     GNUNET_SCHEDULER_cancel (th->timeout_task);
1611     th->timeout_task = NULL;
1612   }
1613   if (NULL != th->connection->write_task)
1614   {
1615     GNUNET_SCHEDULER_cancel (th->connection->write_task);
1616     th->connection->write_task = NULL;
1617   }
1618 }
1619
1620
1621 /**
1622  * Create a connection to be proxied using a given connection.
1623  *
1624  * @param cph connection to proxy server
1625  * @return connection to be proxied
1626  */
1627 struct GNUNET_CONNECTION_Handle *
1628 GNUNET_CONNECTION_create_proxied_from_handshake (struct GNUNET_CONNECTION_Handle *cph)
1629 {
1630   struct GNUNET_CONNECTION_Handle *proxied = GNUNET_CONNECTION_create_from_existing (NULL);
1631
1632   proxied->proxy_handshake = cph;
1633   return proxied;
1634 }
1635
1636
1637 /**
1638  * Activate proxied connection and destroy initial proxy handshake connection.
1639  * There must not be any pending requests for reading or writing to the
1640  * proxy hadshake connection at this time.
1641  *
1642  * @param proxied connection connection to proxy server
1643  */
1644 void
1645 GNUNET_CONNECTION_acivate_proxied (struct GNUNET_CONNECTION_Handle *proxied)
1646 {
1647   struct GNUNET_CONNECTION_Handle *cph = proxied->proxy_handshake;
1648
1649   GNUNET_assert (NULL != cph);
1650   GNUNET_assert (NULL == proxied->sock);
1651   GNUNET_assert (NULL != cph->sock);
1652   proxied->sock = cph->sock;
1653   cph->sock = NULL;
1654   GNUNET_CONNECTION_destroy (cph);
1655   connect_success_continuation (proxied);
1656 }
1657
1658
1659 /* end of connection.c */