2 This file is part of GNUnet.
3 (C) 2013 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 3, or (at your
8 option) any later version.
10 GNUnet is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with GNUnet; see the file COPYING. If not, write to the
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA.
23 #include "gnunet_util_lib.h"
25 #include "gnunet_statistics_service.h"
28 #include "mesh_protocol.h"
30 #include "gnunet-service-mesh_channel.h"
31 #include "gnunet-service-mesh_local.h"
32 #include "gnunet-service-mesh_tunnel.h"
33 #include "gnunet-service-mesh_peer.h"
35 #define LOG(level, ...) GNUNET_log_from(level,"mesh-chn",__VA_ARGS__)
37 #define MESH_RETRANSMIT_TIME GNUNET_TIME_UNIT_SECONDS
38 #define MESH_RETRANSMIT_MARGIN 4
42 * All the states a connection can be in.
47 * Uninitialized status, should never appear in operation.
52 * Connection create message sent, waiting for ACK.
57 * Connection confirmed, ready to carry traffic.
65 * Info needed to retry a message in case it gets lost.
67 struct MeshReliableMessage
70 * Double linked list, FIFO style
72 struct MeshReliableMessage *next;
73 struct MeshReliableMessage *prev;
76 * Type of message (payload, channel management).
81 * Tunnel Reliability queue this message is in.
83 struct MeshChannelReliability *rel;
86 * ID of the message (ACK needed to free)
93 struct MeshTunnel3Queue *q;
96 * When was this message issued (to calculate ACK delay)
98 struct GNUNET_TIME_Absolute timestamp;
100 /* struct GNUNET_MESH_Data with payload */
105 * Info about the traffic state for a client in a channel.
107 struct MeshChannelReliability
110 * Channel this is about.
112 struct MeshChannel *ch;
115 * DLL of messages sent and not yet ACK'd.
117 struct MeshReliableMessage *head_sent;
118 struct MeshReliableMessage *tail_sent;
121 * DLL of messages received out of order.
123 struct MeshReliableMessage *head_recv;
124 struct MeshReliableMessage *tail_recv;
132 * Next MID to use for outgoing traffic.
137 * Next MID expected for incoming traffic.
142 * Can we send data to the client?
147 * Can the client send data to us?
152 * Task to resend/poll in case no ACK is received.
154 GNUNET_SCHEDULER_TaskIdentifier retry_task;
157 * Counter for exponential backoff.
159 struct GNUNET_TIME_Relative retry_timer;
162 * How long does it usually take to get an ACK.
164 struct GNUNET_TIME_Relative expected_delay;
169 * Struct containing all information regarding a channel to a remote client.
174 * Tunnel this channel is in.
176 struct MeshTunnel3 *t;
179 * Destination port of the channel.
184 * Global channel number ( < GNUNET_MESH_LOCAL_CHANNEL_ID_CLI)
186 MESH_ChannelNumber gid;
189 * Local tunnel number for root (owner) client.
190 * ( >= GNUNET_MESH_LOCAL_CHANNEL_ID_CLI or 0 )
192 MESH_ChannelNumber lid_root;
195 * Local tunnel number for local destination clients (incoming number)
196 * ( >= GNUNET_MESH_LOCAL_CHANNEL_ID_SERV or 0).
198 MESH_ChannelNumber lid_dest;
203 enum MeshChannelState state;
206 * Is the tunnel bufferless (minimum latency)?
211 * Is the tunnel reliable?
216 * Last time the channel was used
218 struct GNUNET_TIME_Absolute timestamp;
221 * Client owner of the tunnel, if any
223 struct MeshClient *root;
226 * Client destination of the tunnel, if any.
228 struct MeshClient *dest;
231 * Flag to signal the destruction of the channel.
232 * If this is set GNUNET_YES the channel will be destroyed
233 * when the queue is empty.
238 * Total messages pending for this channel, payload or not.
240 unsigned int pending_messages;
244 * Only present (non-NULL) at the owner of a tunnel.
246 struct MeshChannelReliability *root_rel;
250 * Only present (non-NULL) at the destination of a tunnel.
252 struct MeshChannelReliability *dest_rel;
257 /******************************************************************************/
258 /******************************* GLOBALS ***********************************/
259 /******************************************************************************/
262 * Global handle to the statistics service.
264 extern struct GNUNET_STATISTICS_Handle *stats;
267 * Local peer own ID (memory efficient handle).
269 extern GNUNET_PEER_Id myid;
272 /******************************************************************************/
273 /******************************** STATIC ***********************************/
274 /******************************************************************************/
277 * Destroy a reliable message after it has been acknowledged, either by
278 * direct mid ACK or bitfield. Updates the appropriate data structures and
279 * timers and frees all memory.
281 * @param copy Message that is no longer needed: remote peer got it.
282 * @param update_time Is the timing information relevant?
283 * If this message is ACK in a batch the timing information
284 * is skewed by the retransmission, count only for the
285 * retransmitted message.
288 rel_message_free (struct MeshReliableMessage *copy, int update_time);
291 * We have received a message out of order, or the client is not ready.
292 * Buffer it until we receive an ACK from the client or the missing
293 * message from the channel.
295 * @param msg Message to buffer (MUST be of type MESH_DATA).
296 * @param rel Reliability data to the corresponding direction.
299 add_buffered_data (const struct GNUNET_MESH_Data *msg,
300 struct MeshChannelReliability *rel)
302 struct MeshReliableMessage *copy;
303 struct MeshReliableMessage *prev;
307 size = ntohs (msg->header.size);
308 mid = ntohl (msg->mid);
310 LOG (GNUNET_ERROR_TYPE_DEBUG, "add_buffered_data %u\n", mid);
312 copy = GNUNET_malloc (sizeof (*copy) + size);
315 copy->type = GNUNET_MESSAGE_TYPE_MESH_DATA;
316 memcpy (©[1], msg, size);
320 // FIXME do something better than O(n), although n < 64...
321 // FIXME start from the end (most messages are the latest ones)
322 for (prev = rel->head_recv; NULL != prev; prev = prev->next)
324 LOG (GNUNET_ERROR_TYPE_DEBUG, " prev %u\n", prev->mid);
325 if (GMC_is_pid_bigger (prev->mid, mid))
327 LOG (GNUNET_ERROR_TYPE_DEBUG, " bingo!\n");
328 GNUNET_CONTAINER_DLL_insert_before (rel->head_recv, rel->tail_recv,
333 LOG (GNUNET_ERROR_TYPE_DEBUG, " insert at tail!\n");
334 GNUNET_CONTAINER_DLL_insert_tail (rel->head_recv, rel->tail_recv, copy);
335 LOG (GNUNET_ERROR_TYPE_DEBUG, "add_buffered_data END\n");
339 * Add a destination client to a channel, initializing all data structures
340 * in the channel and the client.
342 * @param ch Channel to which add the destination.
343 * @param c Client which to add to the channel.
346 add_destination (struct MeshChannel *ch, struct MeshClient *c)
348 if (NULL != ch->dest)
354 /* Assign local id as destination */
355 ch->lid_dest = GML_get_next_chid (c);
357 /* Store in client's hashmap */
358 GML_channel_add (c, ch->lid_dest, ch);
360 GNUNET_break (NULL == ch->dest_rel);
361 ch->dest_rel = GNUNET_new (struct MeshChannelReliability);
362 ch->dest_rel->ch = ch;
363 ch->dest_rel->expected_delay = MESH_RETRANSMIT_TIME;
370 * Send data to a client.
372 * If the client is ready, send directly, otherwise buffer while listening
376 * @param msg Message.
377 * @param fwd Is this a fwd (root->dest) message?
380 send_client_data (struct MeshChannel *ch,
381 const struct GNUNET_MESH_Data *msg,
386 if (ch->dest_rel->client_ready)
387 GML_send_data (ch->dest, msg, ch->lid_dest);
389 add_buffered_data (msg, ch->dest_rel);
393 if (ch->root_rel->client_ready)
394 GML_send_data (ch->root, msg, ch->lid_root);
396 add_buffered_data (msg, ch->root_rel);
402 * Send a buffered message to the client, for in order delivery or
403 * as result of client ACK.
405 * @param ch Channel on which to empty the message buffer.
406 * @param c Client to send to.
407 * @param fwd Is this to send FWD data?.
410 send_client_buffered_data (struct MeshChannel *ch,
411 struct MeshClient *c,
414 struct MeshReliableMessage *copy;
415 struct MeshChannelReliability *rel;
417 LOG (GNUNET_ERROR_TYPE_DEBUG, "send_buffered_data\n");
418 rel = fwd ? ch->dest_rel : ch->root_rel;
419 if (GNUNET_NO == rel->client_ready)
421 LOG (GNUNET_ERROR_TYPE_DEBUG, "client not ready\n");
425 copy = rel->head_recv;
426 /* We never buffer channel management messages */
429 if (copy->mid == rel->mid_recv || GNUNET_NO == ch->reliable)
431 struct GNUNET_MESH_Data *msg = (struct GNUNET_MESH_Data *) ©[1];
433 LOG (GNUNET_ERROR_TYPE_DEBUG,
434 " have %u! now expecting %u\n",
435 copy->mid, rel->mid_recv + 1);
436 send_client_data (ch, msg, fwd);
439 GNUNET_CONTAINER_DLL_remove (rel->head_recv, rel->tail_recv, copy);
444 LOG (GNUNET_ERROR_TYPE_DEBUG,
445 " reliable && don't have %u, next is %u\n",
451 LOG (GNUNET_ERROR_TYPE_DEBUG, "send_buffered_data END\n");
456 * Allow a client to send more data.
458 * In case the client was already allowed to send data, do nothing.
461 * @param fwd Is this a FWD ACK? (FWD ACKs are sent to root)
464 send_client_ack (struct MeshChannel *ch, int fwd)
466 struct MeshChannelReliability *rel = fwd ? ch->root_rel : ch->dest_rel;
468 LOG (GNUNET_ERROR_TYPE_DEBUG,
469 " sending %s ack to client on channel %s\n",
470 fwd ? "FWD" : "BCK", GMCH_2s (ch));
478 if (GNUNET_YES == rel->client_allowed)
480 LOG (GNUNET_ERROR_TYPE_DEBUG, " already allowed\n");
483 rel->client_allowed = GNUNET_YES;
485 GML_send_ack (fwd ? ch->root : ch->dest, fwd ? ch->lid_root : ch->lid_dest);
490 * Notify the root that the destination rejected the channel.
492 * @param ch Rejected channel.
495 send_client_nack (struct MeshChannel *ch)
497 if (NULL == ch->root)
502 GML_send_nack (ch->root, ch->lid_root);
507 * Destroy all reliable messages queued for a channel,
508 * during a channel destruction.
509 * Frees the reliability structure itself.
511 * @param rel Reliability data for a channel.
514 channel_rel_free_all (struct MeshChannelReliability *rel)
516 struct MeshReliableMessage *copy;
517 struct MeshReliableMessage *next;
522 for (copy = rel->head_recv; NULL != copy; copy = next)
525 GNUNET_CONTAINER_DLL_remove (rel->head_recv, rel->tail_recv, copy);
528 for (copy = rel->head_sent; NULL != copy; copy = next)
531 GNUNET_CONTAINER_DLL_remove (rel->head_sent, rel->tail_sent, copy);
534 if (GNUNET_SCHEDULER_NO_TASK != rel->retry_task)
535 GNUNET_SCHEDULER_cancel (rel->retry_task);
541 * Mark future messages as ACK'd.
543 * @param rel Reliability data.
544 * @param msg DataACK message with a bitfield of future ACK'd messages.
547 channel_rel_free_sent (struct MeshChannelReliability *rel,
548 const struct GNUNET_MESH_DataACK *msg)
550 struct MeshReliableMessage *copy;
551 struct MeshReliableMessage *next;
558 bitfield = msg->futures;
559 mid = ntohl (msg->mid);
560 LOG (GNUNET_ERROR_TYPE_DEBUG,
561 "!!! free_sent_reliable %u %llX\n",
563 LOG (GNUNET_ERROR_TYPE_DEBUG,
564 " rel %p, head %p\n",
565 rel, rel->head_sent);
566 for (i = 0, copy = rel->head_sent;
567 i < 64 && NULL != copy && 0 != bitfield;
570 LOG (GNUNET_ERROR_TYPE_DEBUG,
571 " trying bit %u (mid %u)\n",
574 if (0 == (bitfield & mask))
577 LOG (GNUNET_ERROR_TYPE_DEBUG, " set!\n");
578 /* Bit was set, clear the bit from the bitfield */
581 /* The i-th bit was set. Do we have that copy? */
582 /* Skip copies with mid < target */
583 target = mid + i + 1;
584 LOG (GNUNET_ERROR_TYPE_DEBUG, " target %u\n", target);
585 while (NULL != copy && GMC_is_pid_bigger (target, copy->mid))
588 /* Did we run out of copies? (previously freed, it's ok) */
591 LOG (GNUNET_ERROR_TYPE_DEBUG, "run out of copies...\n");
595 /* Did we overshoot the target? (previously freed, it's ok) */
596 if (GMC_is_pid_bigger (copy->mid, target))
598 LOG (GNUNET_ERROR_TYPE_DEBUG, " next copy %u\n", copy->mid);
602 /* Now copy->mid == target, free it */
604 rel_message_free (copy, GNUNET_YES);
607 LOG (GNUNET_ERROR_TYPE_DEBUG, "free_sent_reliable END\n");
612 * We haven't received an ACK after a certain time: restransmit the message.
614 * @param cls Closure (MeshReliableMessage with the message to restransmit)
615 * @param tc TaskContext.
618 channel_retransmit_message (void *cls,
619 const struct GNUNET_SCHEDULER_TaskContext *tc)
621 struct MeshChannelReliability *rel = cls;
622 struct MeshReliableMessage *copy;
623 struct MeshChannel *ch;
624 struct GNUNET_MESH_Data *payload;
627 rel->retry_task = GNUNET_SCHEDULER_NO_TASK;
628 if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
632 copy = rel->head_sent;
639 payload = (struct GNUNET_MESH_Data *) ©[1];
640 fwd = (rel == ch->root_rel);
642 /* Message not found in the queue that we are going to use. */
643 LOG (GNUNET_ERROR_TYPE_DEBUG, "!!! RETRANSMIT %u\n", copy->mid);
645 GMCH_send_prebuilt_message (&payload->header, ch, fwd, GNUNET_YES);
646 GNUNET_STATISTICS_update (stats, "# data retransmitted", 1, GNUNET_NO);
648 copy->timestamp = GNUNET_TIME_absolute_get();
649 rel->retry_timer = GNUNET_TIME_STD_BACKOFF (rel->retry_timer);
650 rel->retry_task = GNUNET_SCHEDULER_add_delayed (rel->retry_timer,
651 &channel_retransmit_message,
657 * Destroy a reliable message after it has been acknowledged, either by
658 * direct mid ACK or bitfield. Updates the appropriate data structures and
659 * timers and frees all memory.
661 * @param copy Message that is no longer needed: remote peer got it.
662 * @param update_time Is the timing information relevant?
663 * If this message is ACK in a batch the timing information
664 * is skewed by the retransmission, count only for the
665 * retransmitted message.
668 rel_message_free (struct MeshReliableMessage *copy, int update_time)
670 struct MeshChannelReliability *rel;
671 struct GNUNET_TIME_Relative time;
674 LOG (GNUNET_ERROR_TYPE_DEBUG, "!!! Freeing %u\n", copy->mid);
677 time = GNUNET_TIME_absolute_get_duration (copy->timestamp);
678 rel->expected_delay.rel_value_us *= 7;
679 rel->expected_delay.rel_value_us += time.rel_value_us;
680 rel->expected_delay.rel_value_us /= 8;
681 LOG (GNUNET_ERROR_TYPE_DEBUG, "!!! took %s\n",
682 GNUNET_STRINGS_relative_time_to_string (time, GNUNET_NO));
683 LOG (GNUNET_ERROR_TYPE_DEBUG, "!!! new expected delay %s\n",
684 GNUNET_STRINGS_relative_time_to_string (rel->expected_delay,
686 rel->retry_timer = rel->expected_delay;
690 LOG (GNUNET_ERROR_TYPE_DEBUG, "!!! batch free, ignoring timing\n");
692 GNUNET_CONTAINER_DLL_remove (rel->head_sent, rel->tail_sent, copy);
698 * Confirm we got a channel create.
700 * @param ch The channel to confirm.
701 * @param fwd Should we send a FWD ACK? (going dest->root)
704 channel_send_ack (struct MeshChannel *ch, int fwd)
706 struct GNUNET_MESH_ChannelManage msg;
708 msg.header.size = htons (sizeof (msg));
709 msg.header.type = htons (GNUNET_MESSAGE_TYPE_MESH_CHANNEL_ACK);
710 LOG (GNUNET_ERROR_TYPE_DEBUG,
711 " sending channel %s ack for channel %s\n",
712 fwd ? "FWD" : "BCK", GMCH_2s (ch));
714 msg.chid = htonl (ch->gid);
715 GMCH_send_prebuilt_message (&msg.header, ch, !fwd, GNUNET_NO);
720 * Notify that a channel create didn't succeed.
722 * @param ch The channel to reject.
725 channel_send_nack (struct MeshChannel *ch)
727 struct GNUNET_MESH_ChannelManage msg;
729 msg.header.size = htons (sizeof (msg));
730 msg.header.type = htons (GNUNET_MESSAGE_TYPE_MESH_CHANNEL_NACK);
731 LOG (GNUNET_ERROR_TYPE_DEBUG,
732 " sending channel NACK for channel %s\n",
735 msg.chid = htonl (ch->gid);
736 GMCH_send_prebuilt_message (&msg.header, ch, GNUNET_NO, GNUNET_NO);
741 * Channel was ACK'd by remote peer, mark as ready and cancel retransmission.
743 * @param ch Channel to mark as ready.
744 * @param fwd Was the ACK message a FWD ACK? (dest->root, SYNACK)
747 channel_confirm (struct MeshChannel *ch, int fwd)
749 struct MeshChannelReliability *rel;
750 struct MeshReliableMessage *copy;
751 struct MeshReliableMessage *next;
753 LOG (GNUNET_ERROR_TYPE_DEBUG,
754 " channel confirm %s %s:%X\n",
755 fwd ? "FWD" : "BCK", GMT_2s (ch->t), ch->gid);
756 ch->state = MESH_CHANNEL_READY;
758 rel = fwd ? ch->root_rel : ch->dest_rel;
759 rel->client_ready = GNUNET_YES;
760 for (copy = rel->head_sent; NULL != copy; copy = next)
762 struct GNUNET_MessageHeader *msg;
765 msg = (struct GNUNET_MessageHeader *) ©[1];
766 if (ntohs (msg->type) == GNUNET_MESSAGE_TYPE_MESH_CHANNEL_CREATE)
768 rel_message_free (copy, GNUNET_YES);
772 send_client_ack (ch, fwd);
774 /* In case of a FWD ACK (SYNACK) send a BCK ACK (ACK). */
776 channel_send_ack (ch, !fwd);
781 * Message has been sent: start retransmission timer.
783 * @param cls Closure (copy sent).
785 * @param q Queue handler (no longer valid).
786 * @param type Type of message.
787 * @param size Size of the message.
790 message_sent (void *cls,
791 struct MeshTunnel3 *t,
792 struct MeshTunnel3Queue *q,
793 uint16_t type, size_t size)
795 struct MeshReliableMessage *copy = cls;
796 struct MeshChannelReliability *rel = copy->rel;
798 copy->timestamp = GNUNET_TIME_absolute_get ();
799 if (GNUNET_SCHEDULER_NO_TASK == rel->retry_task)
802 GNUNET_TIME_relative_multiply (rel->expected_delay,
803 MESH_RETRANSMIT_MARGIN);
805 GNUNET_SCHEDULER_add_delayed (rel->retry_timer,
806 &channel_retransmit_message,
813 * Save a copy to retransmit in case it gets lost.
815 * Initializes all needed callbacks and timers.
817 * @param ch Channel this message goes on.
818 * @param msg Message to copy.
819 * @param fwd Is this fwd traffic?
821 static struct MeshReliableMessage *
822 channel_save_copy (struct MeshChannel *ch,
823 const struct GNUNET_MessageHeader *msg,
826 struct MeshChannelReliability *rel;
827 struct MeshReliableMessage *copy;
832 rel = fwd ? ch->root_rel : ch->dest_rel;
833 mid = rel->mid_send - 1;
834 type = ntohs (msg->type);
835 size = ntohs (msg->size);
837 LOG (GNUNET_ERROR_TYPE_DEBUG, "!!! SAVE %u %s\n",
838 mid, GNUNET_MESH_DEBUG_M2S (type));
839 copy = GNUNET_malloc (sizeof (struct MeshReliableMessage) + size);
843 memcpy (©[1], msg, size);
844 GNUNET_CONTAINER_DLL_insert_tail (rel->head_sent, rel->tail_sent, copy);
851 * Create a new channel.
853 * @param t Tunnel this channel is in.
854 * @param owner Client that owns the channel, NULL for foreign channels.
855 * @param lid_root Local ID for root client.
857 * @return A new initialized channel. NULL on error.
859 static struct MeshChannel *
860 channel_new (struct MeshTunnel3 *t,
861 struct MeshClient *owner,
862 MESH_ChannelNumber lid_root)
864 struct MeshChannel *ch;
866 ch = GNUNET_new (struct MeshChannel);
868 ch->lid_root = lid_root;
871 GNUNET_STATISTICS_update (stats, "# channels", 1, GNUNET_NO);
875 ch->gid = GMT_get_next_chid (t);
876 GML_channel_add (owner, lid_root, ch);
878 GMT_add_channel (t, ch);
885 * Set options in a channel, extracted from a bit flag field
887 * @param ch Channel to set options to.
888 * @param options Bit array in host byte order.
891 channel_set_options (struct MeshChannel *ch, uint32_t options)
893 ch->nobuffer = (options & GNUNET_MESH_OPTION_NOBUFFER) != 0 ?
894 GNUNET_YES : GNUNET_NO;
895 ch->reliable = (options & GNUNET_MESH_OPTION_RELIABLE) != 0 ?
896 GNUNET_YES : GNUNET_NO;
900 is_loopback (const struct MeshChannel *ch)
903 return GMT_is_loopback (ch->t);
905 return (NULL != ch->root && NULL != ch->dest);
910 * Handle a loopback message: call the appropriate handler for the message type.
912 * @param ch Channel this message is on.
913 * @param msgh Message header.
914 * @param fwd Is this FWD traffic?
917 handle_loopback (struct MeshChannel *ch,
918 const struct GNUNET_MessageHeader *msgh,
923 type = ntohs (msgh->type);
924 LOG (GNUNET_ERROR_TYPE_DEBUG,
925 "Loopback %s %s message!\n",
926 fwd ? "FWD" : "BCK", GNUNET_MESH_DEBUG_M2S (type));
930 case GNUNET_MESSAGE_TYPE_MESH_DATA:
931 /* Don't send hop ACK, wait for client to ACK */
932 GMCH_handle_data (ch, (struct GNUNET_MESH_Data *) msgh, fwd);
935 case GNUNET_MESSAGE_TYPE_MESH_DATA_ACK:
936 GMCH_handle_data_ack (ch, (struct GNUNET_MESH_DataACK *) msgh, fwd);
939 case GNUNET_MESSAGE_TYPE_MESH_CHANNEL_CREATE:
940 GMCH_handle_create (ch->t,
941 (struct GNUNET_MESH_ChannelCreate *) msgh);
944 case GNUNET_MESSAGE_TYPE_MESH_CHANNEL_ACK:
946 (struct GNUNET_MESH_ChannelManage *) msgh,
950 case GNUNET_MESSAGE_TYPE_MESH_CHANNEL_NACK:
951 GMCH_handle_nack (ch);
954 case GNUNET_MESSAGE_TYPE_MESH_CHANNEL_DESTROY:
955 GMCH_handle_destroy (ch,
956 (struct GNUNET_MESH_ChannelManage *) msgh,
962 LOG (GNUNET_ERROR_TYPE_DEBUG,
963 "end-to-end message not known (%u)\n",
970 /******************************************************************************/
971 /******************************** API ***********************************/
972 /******************************************************************************/
975 * Destroy a channel and free all resources.
977 * @param ch Channel to destroy.
980 GMCH_destroy (struct MeshChannel *ch)
982 struct MeshClient *c;
987 LOG (GNUNET_ERROR_TYPE_DEBUG, "destroying channel %s:%u\n",
988 GMT_2s (ch->t), ch->gid);
994 GML_channel_remove (c, ch->lid_root, ch);
1000 GML_channel_remove (c, ch->lid_dest, ch);
1003 channel_rel_free_all (ch->root_rel);
1004 channel_rel_free_all (ch->dest_rel);
1006 GMT_remove_channel (ch->t, ch);
1007 GNUNET_STATISTICS_update (stats, "# channels", -1, GNUNET_NO);
1016 * @param ch Channel.
1021 GMCH_get_id (const struct MeshChannel *ch)
1028 * Get the channel tunnel.
1030 * @param ch Channel to get the tunnel from.
1032 * @return tunnel of the channel.
1034 struct MeshTunnel3 *
1035 GMCH_get_tunnel (const struct MeshChannel *ch)
1042 * Get free buffer space towards the client on a specific channel.
1044 * @param ch Channel.
1045 * @param fwd Is query about FWD traffic?
1047 * @return Free buffer space [0 - 64]
1050 GMCH_get_buffer (struct MeshChannel *ch, int fwd)
1052 struct MeshChannelReliability *rel;
1054 rel = fwd ? ch->dest_rel : ch->root_rel;
1056 /* If rel is NULL it means that the end is not yet created,
1057 * most probably is a loopback channel at the point of sending
1058 * the ChannelCreate to itself.
1063 return (64 - rel->n_recv);
1068 * Get flow control status of end point: is client allow to send?
1070 * @param ch Channel.
1071 * @param fwd Is query about FWD traffic? (Request root status).
1073 * @return #GNUNET_YES if client is allowed to send us data.
1076 GMCH_get_allowed (struct MeshChannel *ch, int fwd)
1078 struct MeshChannelReliability *rel;
1080 rel = fwd ? ch->root_rel : ch->dest_rel;
1082 return rel->client_allowed;
1087 * Is the root client for this channel on this peer?
1089 * @param ch Channel.
1090 * @param fwd Is this for fwd traffic?
1092 * @return #GNUNET_YES in case it is.
1095 GMCH_is_origin (struct MeshChannel *ch, int fwd)
1097 struct MeshClient *c;
1099 c = fwd ? ch->root : ch->dest;
1105 * Is the destination client for this channel on this peer?
1107 * @param ch Channel.
1108 * @param fwd Is this for fwd traffic?
1110 * @return #GNUNET_YES in case it is.
1113 GMCH_is_terminal (struct MeshChannel *ch, int fwd)
1115 struct MeshClient *c;
1117 c = fwd ? ch->dest : ch->root;
1123 * Notify the destination client that a new incoming channel was created.
1125 * @param ch Channel that was created.
1128 GMCH_send_create (struct MeshChannel *ch)
1132 if (NULL == ch->dest)
1136 opt |= GNUNET_YES == ch->reliable ? GNUNET_MESH_OPTION_RELIABLE : 0;
1137 opt |= GNUNET_YES == ch->nobuffer ? GNUNET_MESH_OPTION_NOBUFFER : 0;
1138 GML_send_channel_create (ch->dest, ch->lid_dest, ch->port, opt,
1139 GMT_get_destination (ch->t));
1144 * Notify a client that the channel is no longer valid.
1146 * @param ch Channel that is destroyed.
1149 GMCH_send_destroy (struct MeshChannel *ch)
1151 struct GNUNET_MESH_ChannelManage msg;
1153 msg.header.type = htons (GNUNET_MESSAGE_TYPE_MESH_CHANNEL_DESTROY);
1154 msg.header.size = htons (sizeof (msg));
1155 msg.chid = htonl (ch->gid);
1157 /* If root is not NULL, notify.
1158 * If it's NULL, check lid_root. When a local destroy comes in, root
1159 * is set to NULL but lid_root is left untouched. In this case, do nothing,
1160 * the client is the one who reuqested the channel to be destroyed.
1162 if (NULL != ch->root)
1163 GML_send_channel_destroy (ch->root, ch->lid_root);
1164 else if (0 == ch->lid_root)
1165 GMCH_send_prebuilt_message (&msg.header, ch, GNUNET_NO, GNUNET_NO);
1167 if (NULL != ch->dest)
1168 GML_send_channel_destroy (ch->dest, ch->lid_dest);
1169 else if (0 == ch->lid_dest)
1170 GMCH_send_prebuilt_message (&msg.header, ch, GNUNET_YES, GNUNET_NO);
1175 * Send an end-to-end ACK message for the most recent in-sequence payload.
1177 * If channel is not reliable, do nothing.
1179 * @param ch Channel this is about.
1180 * @param fwd Is for FWD traffic? (ACK dest->owner)
1183 GMCH_send_data_ack (struct MeshChannel *ch, int fwd)
1185 struct GNUNET_MESH_DataACK msg;
1186 struct MeshChannelReliability *rel;
1187 struct MeshReliableMessage *copy;
1192 if (GNUNET_NO == ch->reliable)
1196 rel = fwd ? ch->dest_rel : ch->root_rel;
1197 ack = rel->mid_recv - 1;
1198 LOG (GNUNET_ERROR_TYPE_DEBUG,
1199 " !! Send DATA_ACK for %u\n",
1202 msg.header.type = htons (GNUNET_MESSAGE_TYPE_MESH_DATA_ACK);
1203 msg.header.size = htons (sizeof (msg));
1204 msg.chid = htonl (ch->gid);
1206 for (copy = rel->head_recv; NULL != copy; copy = copy->next)
1208 if (copy->type != GNUNET_MESSAGE_TYPE_MESH_DATA)
1210 LOG (GNUNET_ERROR_TYPE_DEBUG,
1211 "!! Type %s, expected DATA\n",
1212 GNUNET_MESH_DEBUG_M2S (copy->type));
1215 if (copy->mid == ack + 1)
1220 delta = copy->mid - (ack + 1);
1223 mask = 0x1LL << delta;
1224 msg.futures |= mask;
1225 LOG (GNUNET_ERROR_TYPE_DEBUG,
1226 " !! setting bit for %u (delta %u) (%llX) -> %llX\n",
1227 copy->mid, delta, mask, msg.futures);
1229 msg.mid = htonl (ack);
1230 LOG (GNUNET_ERROR_TYPE_DEBUG,
1231 "!!! ACK for %u, futures %llX\n",
1234 GMCH_send_prebuilt_message (&msg.header, ch, !fwd, GNUNET_NO);
1235 LOG (GNUNET_ERROR_TYPE_DEBUG, "send_data_ack END\n");
1240 * Allow a client to send us more data, in case it was choked.
1242 * @param ch Channel.
1243 * @param fwd Is this about FWD traffic? (Root client).
1246 GMCH_allow_client (struct MeshChannel *ch, int fwd)
1248 struct MeshChannelReliability *rel;
1249 unsigned int buffer;
1251 LOG (GNUNET_ERROR_TYPE_DEBUG, "GMCH allow\n");
1253 if (MESH_CHANNEL_READY != ch->state)
1255 LOG (GNUNET_ERROR_TYPE_DEBUG, " channel not ready yet!\n");
1259 if (GNUNET_YES == ch->reliable)
1261 rel = fwd ? ch->root_rel : ch->dest_rel;
1267 if (NULL != rel->head_sent && 64 <= rel->mid_send - rel->head_sent->mid)
1269 LOG (GNUNET_ERROR_TYPE_DEBUG, " too big MID gap! Wait for ACK.\n");
1274 if (is_loopback (ch))
1275 buffer = GMCH_get_buffer (ch, fwd);
1277 buffer = GMT_get_connections_buffer (ch->t);
1281 LOG (GNUNET_ERROR_TYPE_DEBUG, " no buffer space.\n");
1285 LOG (GNUNET_ERROR_TYPE_DEBUG, " buffer space %u, allowing\n", buffer);
1286 send_client_ack (ch, fwd);
1293 * @param ch Channel.
1296 GMCH_debug (struct MeshChannel *ch)
1300 LOG (GNUNET_ERROR_TYPE_DEBUG, "*** DEBUG NULL CHANNEL ***\n");
1303 LOG (GNUNET_ERROR_TYPE_DEBUG, "Channel %s:%X (%p)\n",
1304 GMT_2s (ch->t), ch->gid, ch);
1305 LOG (GNUNET_ERROR_TYPE_DEBUG, " root %p/%p\n",
1306 ch->root, ch->root_rel);
1307 if (NULL != ch->root)
1309 LOG (GNUNET_ERROR_TYPE_DEBUG, " cli %s\n", GML_2s (ch->root));
1310 LOG (GNUNET_ERROR_TYPE_DEBUG, " ready %s\n",
1311 ch->root_rel->client_ready ? "YES" : "NO");
1312 LOG (GNUNET_ERROR_TYPE_DEBUG, " id %X\n", ch->lid_root);
1314 LOG (GNUNET_ERROR_TYPE_DEBUG, " dest %p/%p\n",
1315 ch->dest, ch->dest_rel);
1316 if (NULL != ch->dest)
1318 LOG (GNUNET_ERROR_TYPE_DEBUG, " cli %s\n", GML_2s (ch->dest));
1319 LOG (GNUNET_ERROR_TYPE_DEBUG, " ready %s\n",
1320 ch->dest_rel->client_ready ? "YES" : "NO");
1321 LOG (GNUNET_ERROR_TYPE_DEBUG, " id %X\n", ch->lid_dest);
1327 * Handle an ACK given by a client.
1329 * Mark client as ready and send him any buffered data we could have for him.
1331 * @param ch Channel.
1332 * @param fwd Is this a "FWD ACK"? (FWD ACKs are sent by dest and go BCK)
1335 GMCH_handle_local_ack (struct MeshChannel *ch, int fwd)
1337 struct MeshChannelReliability *rel;
1338 struct MeshClient *c;
1340 rel = fwd ? ch->dest_rel : ch->root_rel;
1341 c = fwd ? ch->dest : ch->root;
1343 rel->client_ready = GNUNET_YES;
1344 send_client_buffered_data (ch, c, fwd);
1345 if (is_loopback (ch))
1347 unsigned int buffer;
1349 buffer = GMCH_get_buffer (ch, fwd);
1351 GMCH_allow_client (ch, fwd);
1355 GMT_send_connection_acks (ch->t);
1360 * Handle data given by a client.
1362 * Check whether the client is allowed to send in this tunnel, save if channel
1363 * is reliable and send an ACK to the client if there is still buffer space
1366 * @param ch Channel.
1367 * @param c Client which sent the data.
1368 * @param message Message.
1369 * @param fwd Is this a FWD data?
1371 * @return GNUNET_OK if everything goes well, GNUNET_SYSERR in case of en error.
1374 GMCH_handle_local_data (struct MeshChannel *ch,
1375 struct MeshClient *c,
1376 struct GNUNET_MessageHeader *message,
1379 struct MeshChannelReliability *rel;
1380 struct GNUNET_MESH_Data *payload;
1381 size_t size = ntohs (message->size);
1382 uint16_t p2p_size = sizeof(struct GNUNET_MESH_Data) + size;
1383 unsigned char cbuf[p2p_size];
1385 /* Is the client in the channel? */
1392 GNUNET_break_op (0);
1393 return GNUNET_SYSERR;
1396 rel = fwd ? ch->root_rel : ch->dest_rel;
1398 if (GNUNET_NO == rel->client_allowed)
1400 GNUNET_break_op (0);
1401 return GNUNET_SYSERR;
1404 rel->client_allowed = GNUNET_NO;
1406 /* Ok, everything is correct, send the message. */
1407 payload = (struct GNUNET_MESH_Data *) cbuf;
1408 payload->mid = htonl (rel->mid_send);
1410 memcpy (&payload[1], message, size);
1411 payload->header.size = htons (p2p_size);
1412 payload->header.type = htons (GNUNET_MESSAGE_TYPE_MESH_DATA);
1413 payload->chid = htonl (ch->gid);
1414 LOG (GNUNET_ERROR_TYPE_DEBUG, " sending on channel...\n");
1415 GMCH_send_prebuilt_message (&payload->header, ch, fwd, GNUNET_NO);
1417 if (is_loopback (ch))
1419 if (GMCH_get_buffer (ch, fwd) > 0)
1420 send_client_ack (ch, fwd);
1425 if (GMT_get_connections_buffer (ch->t) > 0)
1427 send_client_ack (ch, fwd);
1435 * Handle a channel destroy requested by a client.
1437 * Destroy the channel and the tunnel in case this was the last channel.
1439 * @param ch Channel.
1440 * @param c Client that requested the destruction (to avoid notifying him).
1443 GMCH_handle_local_destroy (struct MeshChannel *ch,
1444 struct MeshClient *c)
1446 struct MeshTunnel3 *t;
1448 /* Cleanup after the tunnel */
1451 LOG (GNUNET_ERROR_TYPE_DEBUG, " Client %s is destination.\n", GML_2s (c));
1452 GML_client_delete_channel (c, ch, ch->lid_dest);
1457 LOG (GNUNET_ERROR_TYPE_DEBUG, " Client %s is owner.\n", GML_2s (c));
1458 GML_client_delete_channel (c, ch, ch->lid_root);
1463 GMCH_send_destroy (ch);
1465 GMT_destroy_if_empty (t);
1470 * Handle a channel create requested by a client.
1472 * Create the channel and the tunnel in case this was the first0 channel.
1474 * @param c Client that requested the creation (will be the root).
1475 * @param msg Create Channel message.
1477 * @return GNUNET_OK if everything went fine, GNUNET_SYSERR otherwise.
1480 GMCH_handle_local_create (struct MeshClient *c,
1481 struct GNUNET_MESH_ChannelMessage *msg)
1483 struct MeshChannel *ch;
1484 struct MeshTunnel3 *t;
1485 struct MeshPeer *peer;
1486 MESH_ChannelNumber chid;
1488 LOG (GNUNET_ERROR_TYPE_DEBUG, " towards %s:%u\n",
1489 GNUNET_i2s (&msg->peer), ntohl (msg->port));
1490 chid = ntohl (msg->channel_id);
1492 /* Sanity check for duplicate channel IDs */
1493 if (NULL != GML_channel_get (c, chid))
1496 return GNUNET_SYSERR;
1499 peer = GMP_get (&msg->peer);
1500 GMP_add_tunnel (peer);
1501 t = GMP_get_tunnel (peer);
1503 if (GMP_get_short_id (peer) == myid)
1505 GMT_change_state (t, MESH_TUNNEL3_READY);
1512 /* Create channel */
1513 ch = channel_new (t, c, chid);
1517 return GNUNET_SYSERR;
1519 ch->port = ntohl (msg->port);
1520 channel_set_options (ch, ntohl (msg->opt));
1522 /* In unreliable channels, we'll use the DLL to buffer BCK data */
1523 ch->root_rel = GNUNET_new (struct MeshChannelReliability);
1524 ch->root_rel->ch = ch;
1525 ch->root_rel->expected_delay = MESH_RETRANSMIT_TIME;
1527 LOG (GNUNET_ERROR_TYPE_DEBUG, "CREATED CHANNEL %s\n", GMCH_2s (ch));
1529 /* Send create channel */
1531 struct GNUNET_MESH_ChannelCreate msgcc;
1533 msgcc.header.size = htons (sizeof (msgcc));
1534 msgcc.header.type = htons (GNUNET_MESSAGE_TYPE_MESH_CHANNEL_CREATE);
1535 msgcc.chid = htonl (ch->gid);
1536 msgcc.port = msg->port;
1537 msgcc.opt = msg->opt;
1539 GMT_send_prebuilt_message (&msgcc.header, t, ch, GNUNET_YES, NULL, NULL);
1546 * Handler for mesh network payload traffic.
1548 * @param ch Channel for the message.
1549 * @param msg Unencryted data message.
1550 * @param fwd Is this message fwd? This only is meaningful in loopback channels.
1551 * #GNUNET_YES if message is FWD on the respective channel (loopback)
1552 * #GNUNET_NO if message is BCK on the respective channel (loopback)
1553 * #GNUNET_SYSERR if message on a one-ended channel (remote)
1556 GMCH_handle_data (struct MeshChannel *ch,
1557 const struct GNUNET_MESH_Data *msg,
1560 struct MeshChannelReliability *rel;
1561 struct MeshClient *c;
1564 /* If this is a remote (non-loopback) channel, find 'fwd'. */
1565 if (GNUNET_SYSERR == fwd)
1567 if (is_loopback (ch))
1569 /* It is a loopback channel after all... */
1573 fwd = (NULL != ch->dest) ? GNUNET_YES : GNUNET_NO;
1576 /* Initialize FWD/BCK data */
1577 c = fwd ? ch->dest : ch->root;
1578 rel = fwd ? ch->dest_rel : ch->root_rel;
1586 GNUNET_STATISTICS_update (stats, "# data received", 1, GNUNET_NO);
1588 mid = ntohl (msg->mid);
1589 LOG (GNUNET_ERROR_TYPE_DEBUG, "!! got mid %u\n", mid);
1591 if (GNUNET_NO == ch->reliable ||
1592 ( !GMC_is_pid_bigger (rel->mid_recv, mid) &&
1593 GMC_is_pid_bigger (rel->mid_recv + 64, mid) ) )
1595 LOG (GNUNET_ERROR_TYPE_DEBUG, "!!! RECV %u\n", mid);
1596 if (GNUNET_YES == ch->reliable)
1598 /* Is this the exact next expected messasge? */
1599 if (mid == rel->mid_recv)
1601 LOG (GNUNET_ERROR_TYPE_DEBUG, "as expected\n");
1603 send_client_data (ch, msg, fwd);
1607 LOG (GNUNET_ERROR_TYPE_DEBUG, "save for later\n");
1608 add_buffered_data (msg, rel);
1613 /* Tunnel is unreliable: send to clients directly */
1614 /* FIXME: accept Out Of Order traffic */
1615 rel->mid_recv = mid + 1;
1616 send_client_data (ch, msg, fwd);
1621 GNUNET_break_op (0);
1622 LOG (GNUNET_ERROR_TYPE_DEBUG,
1623 " MID %u not expected (%u - %u), dropping!\n",
1624 mid, rel->mid_recv, rel->mid_recv + 63);
1627 GMCH_send_data_ack (ch, fwd);
1632 * Handler for mesh network traffic end-to-end ACKs.
1634 * @param ch Channel on which we got this message.
1635 * @param msg Data message.
1636 * @param fwd Is this message fwd? This only is meaningful in loopback channels.
1637 * #GNUNET_YES if message is FWD on the respective channel (loopback)
1638 * #GNUNET_NO if message is BCK on the respective channel (loopback)
1639 * #GNUNET_SYSERR if message on a one-ended channel (remote)
1642 GMCH_handle_data_ack (struct MeshChannel *ch,
1643 const struct GNUNET_MESH_DataACK *msg,
1646 struct MeshChannelReliability *rel;
1647 struct MeshReliableMessage *copy;
1648 struct MeshReliableMessage *next;
1652 /* If this is a remote (non-loopback) channel, find 'fwd'. */
1653 if (GNUNET_SYSERR == fwd)
1655 if (is_loopback (ch))
1657 /* It is a loopback channel after all... */
1661 /* Inverted: if message came 'FWD' is a 'BCK ACK'. */
1662 fwd = (NULL != ch->dest) ? GNUNET_NO : GNUNET_YES;
1665 ack = ntohl (msg->mid);
1666 LOG (GNUNET_ERROR_TYPE_DEBUG, "!!! %s ACK %u\n",
1667 (GNUNET_YES == fwd) ? "FWD" : "BCK", ack);
1669 if (GNUNET_YES == fwd)
1679 GNUNET_break_op (0);
1683 /* Free ACK'd copies: no need to retransmit those anymore */
1684 for (work = GNUNET_NO, copy = rel->head_sent; copy != NULL; copy = next)
1686 if (GMC_is_pid_bigger (copy->mid, ack))
1688 LOG (GNUNET_ERROR_TYPE_DEBUG, "!!! head %u, out!\n", copy->mid);
1689 channel_rel_free_sent (rel, msg);
1693 LOG (GNUNET_ERROR_TYPE_DEBUG, " !! id %u\n", copy->mid);
1695 rel_message_free (copy, GNUNET_YES);
1698 /* ACK client if needed */
1699 GMCH_allow_client (ch, fwd);
1701 /* If some message was free'd, update the retransmission delay */
1702 if (GNUNET_YES == work)
1704 if (GNUNET_SCHEDULER_NO_TASK != rel->retry_task)
1706 GNUNET_SCHEDULER_cancel (rel->retry_task);
1707 if (NULL == rel->head_sent)
1709 rel->retry_task = GNUNET_SCHEDULER_NO_TASK;
1713 struct GNUNET_TIME_Absolute new_target;
1714 struct GNUNET_TIME_Relative delay;
1716 delay = GNUNET_TIME_relative_multiply (rel->retry_timer,
1717 MESH_RETRANSMIT_MARGIN);
1718 new_target = GNUNET_TIME_absolute_add (rel->head_sent->timestamp,
1720 delay = GNUNET_TIME_absolute_get_remaining (new_target);
1722 GNUNET_SCHEDULER_add_delayed (delay,
1723 &channel_retransmit_message,
1734 * Handler for channel create messages.
1736 * Does not have fwd parameter because it's always 'FWD': channel is incoming.
1738 * @param t Tunnel this channel will be in.
1739 * @param msg Channel crate message.
1741 struct MeshChannel *
1742 GMCH_handle_create (struct MeshTunnel3 *t,
1743 const struct GNUNET_MESH_ChannelCreate *msg)
1745 MESH_ChannelNumber chid;
1746 struct MeshChannel *ch;
1747 struct MeshClient *c;
1750 chid = ntohl (msg->chid);
1752 ch = GMT_get_channel (t, chid);
1755 /* Create channel */
1756 ch = channel_new (t, NULL, 0);
1759 channel_set_options (ch, ntohl (msg->opt));
1761 /* Find a destination client */
1762 port = ntohl (msg->port);
1763 LOG (GNUNET_ERROR_TYPE_DEBUG, " port %u\n", port);
1764 c = GML_client_get_by_port (port);
1767 /* TODO send reject */
1768 LOG (GNUNET_ERROR_TYPE_DEBUG, " no client has port registered\n");
1769 if (is_loopback (ch))
1771 LOG (GNUNET_ERROR_TYPE_DEBUG, " loopback: destroy on handler\n");
1772 channel_send_nack (ch);
1776 LOG (GNUNET_ERROR_TYPE_DEBUG, " not loopback: destroy now\n");
1777 channel_send_nack (ch);
1784 LOG (GNUNET_ERROR_TYPE_DEBUG, " client %p has port registered\n", c);
1787 add_destination (ch, c);
1788 if (GNUNET_YES == ch->reliable)
1789 LOG (GNUNET_ERROR_TYPE_DEBUG, "!!! Reliable\n");
1791 LOG (GNUNET_ERROR_TYPE_DEBUG, "!!! Not Reliable\n");
1793 GMCH_send_create (ch);
1794 channel_send_ack (ch, GNUNET_YES);
1801 * Handler for channel NACK messages.
1803 * NACK messages always go dest -> root, no need for 'fwd' or 'msg' parameter.
1805 * @param ch Channel.
1808 GMCH_handle_nack (struct MeshChannel *ch)
1810 send_client_nack (ch);
1816 * Handler for channel ack messages.
1818 * @param ch Channel.
1819 * @param msg Message.
1820 * @param fwd Is this message fwd? This only is meaningful in loopback channels.
1821 * #GNUNET_YES if message is FWD on the respective channel (loopback)
1822 * #GNUNET_NO if message is BCK on the respective channel (loopback)
1823 * #GNUNET_SYSERR if message on a one-ended channel (remote)
1826 GMCH_handle_ack (struct MeshChannel *ch,
1827 const struct GNUNET_MESH_ChannelManage *msg,
1830 /* If this is a remote (non-loopback) channel, find 'fwd'. */
1831 if (GNUNET_SYSERR == fwd)
1833 if (is_loopback (ch))
1835 /* It is a loopback channel after all... */
1839 fwd = (NULL != ch->dest) ? GNUNET_YES : GNUNET_NO;
1842 channel_confirm (ch, !fwd);
1847 * Handler for channel destroy messages.
1849 * @param ch Channel to be destroyed of.
1850 * @param msg Message.
1851 * @param fwd Is this message fwd? This only is meaningful in loopback channels.
1852 * #GNUNET_YES if message is FWD on the respective channel (loopback)
1853 * #GNUNET_NO if message is BCK on the respective channel (loopback)
1854 * #GNUNET_SYSERR if message on a one-ended channel (remote)
1857 GMCH_handle_destroy (struct MeshChannel *ch,
1858 const struct GNUNET_MESH_ChannelManage *msg,
1861 struct MeshTunnel3 *t;
1863 /* If this is a remote (non-loopback) channel, find 'fwd'. */
1864 if (GNUNET_SYSERR == fwd)
1866 if (is_loopback (ch))
1868 /* It is a loopback channel after all... */
1872 fwd = (NULL != ch->dest) ? GNUNET_YES : GNUNET_NO;
1876 if ( (fwd && NULL == ch->dest) || (!fwd && NULL == ch->root) )
1878 /* Not for us (don't destroy twice a half-open loopback channel) */
1883 GMCH_send_destroy (ch);
1885 GMT_destroy_if_empty (t);
1890 * Sends an already built message on a channel.
1892 * If the channel is on a loopback tunnel, notifies the appropriate destination
1895 * On a normal channel passes the message to the tunnel for encryption and
1896 * sending on a connection.
1898 * This function DOES NOT save the message for retransmission.
1900 * @param message Message to send. Function makes a copy of it.
1901 * @param ch Channel on which this message is transmitted.
1902 * @param fwd Is this a fwd message?
1903 * @param retransmission Is this a retransmission? (Don't save a copy)
1906 GMCH_send_prebuilt_message (const struct GNUNET_MessageHeader *message,
1907 struct MeshChannel *ch, int fwd,
1910 LOG (GNUNET_ERROR_TYPE_DEBUG, "GMCH Send %s %s on channel %s\n",
1911 fwd ? "FWD" : "BCK", GNUNET_MESH_DEBUG_M2S (ntohs (message->type)),
1914 if (GMT_is_loopback (ch->t))
1916 handle_loopback (ch, message, fwd);
1920 if (GNUNET_YES == ch->reliable && GNUNET_NO == retransmission
1921 && ntohs (message->type) == GNUNET_MESSAGE_TYPE_MESH_DATA)
1923 struct MeshReliableMessage *copy;
1925 copy = channel_save_copy (ch, message, fwd);
1926 copy->q = GMT_send_prebuilt_message (message, ch->t, ch, fwd,
1927 &message_sent, copy);
1930 GMT_send_prebuilt_message (message, ch->t, ch, fwd, NULL, NULL);
1935 * Get the static string for identification of the channel.
1937 * @param ch Channel.
1939 * @return Static string with the channel IDs.
1942 GMCH_2s (const struct MeshChannel *ch)
1944 static char buf[64];
1947 return "(NULL Channel)";
1949 sprintf (buf, "%s:%X (%X / %X)",
1950 GMT_2s (ch->t), ch->gid, ch->lid_root, ch->lid_dest);