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3 (C) 2009, 2010, 2011 Christian Grothoff (and other contributing authors)
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22 * @file core/gnunet-service-core_sessions.c
23 * @brief code for managing of 'encrypted' sessions (key exchange done)
24 * @author Christian Grothoff
27 #include "gnunet-service-core.h"
28 #include "gnunet-service-core_neighbours.h"
29 #include "gnunet-service-core_kx.h"
30 #include "gnunet-service-core_typemap.h"
31 #include "gnunet-service-core_sessions.h"
32 #include "gnunet-service-core_clients.h"
33 #include "gnunet_constants.h"
36 * How often do we transmit our typemap?
38 #define TYPEMAP_FREQUENCY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 5)
42 * Message ready for encryption. This struct is followed by the
43 * actual content of the message.
45 struct SessionMessageEntry
49 * We keep messages in a doubly linked list.
51 struct SessionMessageEntry *next;
54 * We keep messages in a doubly linked list.
56 struct SessionMessageEntry *prev;
59 * Deadline for transmission, 1s after we received it (if we
60 * are not corking), otherwise "now". Note that this message
61 * does NOT expire past its deadline.
63 struct GNUNET_TIME_Absolute deadline;
66 * How long is the message? (number of bytes following the "struct
67 * MessageEntry", but not including the size of "struct
68 * MessageEntry" itself!)
76 * Data kept per session.
81 * Identity of the other peer.
83 struct GNUNET_PeerIdentity peer;
86 * Head of list of requests from clients for transmission to
89 struct GSC_ClientActiveRequest *active_client_request_head;
92 * Tail of list of requests from clients for transmission to
95 struct GSC_ClientActiveRequest *active_client_request_tail;
98 * Head of list of messages ready for encryption.
100 struct SessionMessageEntry *sme_head;
103 * Tail of list of messages ready for encryption.
105 struct SessionMessageEntry *sme_tail;
108 * Information about the key exchange with the other peer.
110 struct GSC_KeyExchangeInfo *kxinfo;
113 * Current type map for this peer.
115 struct GSC_TypeMap *tmap;
118 * At what time did we initially establish this session?
119 * (currently unused, should be integrated with ATS in the
122 struct GNUNET_TIME_Absolute time_established;
125 * Task to transmit corked messages with a delay.
127 GNUNET_SCHEDULER_TaskIdentifier cork_task;
130 * Task to transmit our type map.
132 GNUNET_SCHEDULER_TaskIdentifier typemap_task;
135 * Is the neighbour queue empty and thus ready for us
136 * to transmit an encrypted message?
138 int ready_to_transmit;
144 * Map of peer identities to 'struct Session'.
146 static struct GNUNET_CONTAINER_MultiHashMap *sessions;
150 * Find the session for the given peer.
152 * @param peer identity of the peer
153 * @return NULL if we are not connected, otherwise the
156 static struct Session *
157 find_session (const struct GNUNET_PeerIdentity *peer)
159 return GNUNET_CONTAINER_multihashmap_get (sessions, &peer->hashPubKey);
164 * End the session with the given peer (we are no longer
167 * @param pid identity of peer to kill session with
170 GSC_SESSIONS_end (const struct GNUNET_PeerIdentity *pid)
172 struct Session *session;
173 struct GSC_ClientActiveRequest *car;
174 struct SessionMessageEntry *sme;
176 session = find_session (pid);
180 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Destroying session for peer `%4s'\n",
181 GNUNET_i2s (&session->peer));
183 if (GNUNET_SCHEDULER_NO_TASK != session->cork_task)
185 GNUNET_SCHEDULER_cancel (session->cork_task);
186 session->cork_task = GNUNET_SCHEDULER_NO_TASK;
188 while (NULL != (car = session->active_client_request_head))
190 GNUNET_CONTAINER_DLL_remove (session->active_client_request_head,
191 session->active_client_request_tail, car);
192 GSC_CLIENTS_reject_request (car);
194 while (NULL != (sme = session->sme_head))
196 GNUNET_CONTAINER_DLL_remove (session->sme_head,
201 GNUNET_SCHEDULER_cancel (session->typemap_task);
202 GSC_CLIENTS_notify_clients_about_neighbour (&session->peer, NULL,
203 0 /* FIXME: ATSI */ ,
204 session->tmap, NULL);
205 GNUNET_assert (GNUNET_YES ==
206 GNUNET_CONTAINER_multihashmap_remove (sessions,
210 GNUNET_STATISTICS_set (GSC_stats, gettext_noop ("# entries in session map"),
211 GNUNET_CONTAINER_multihashmap_size (sessions),
213 GSC_TYPEMAP_destroy (session->tmap);
214 session->tmap = NULL;
215 GNUNET_free (session);
220 * Transmit our current typemap message to the other peer.
221 * (Done periodically in case an update got lost).
223 * @param cls the 'struct Session*'
227 transmit_typemap_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
229 struct Session *session = cls;
230 struct GNUNET_MessageHeader *hdr;
231 struct GNUNET_TIME_Relative delay;
233 delay = TYPEMAP_FREQUENCY;
234 /* randomize a bit to avoid spont. sync */
236 GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, 1000);
237 session->typemap_task =
238 GNUNET_SCHEDULER_add_delayed (delay, &transmit_typemap_task, session);
239 GNUNET_STATISTICS_update (GSC_stats,
240 gettext_noop ("# type map refreshes sent"), 1,
242 hdr = GSC_TYPEMAP_compute_type_map_message ();
243 GSC_KX_encrypt_and_transmit (session->kxinfo, hdr, ntohs (hdr->size));
249 * Create a session, a key exchange was just completed.
251 * @param peer peer that is now connected
252 * @param kx key exchange that completed
255 GSC_SESSIONS_create (const struct GNUNET_PeerIdentity *peer,
256 struct GSC_KeyExchangeInfo *kx)
258 struct Session *session;
261 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Creating session for peer `%4s'\n",
264 session = GNUNET_malloc (sizeof (struct Session));
265 session->tmap = GSC_TYPEMAP_create ();
266 session->peer = *peer;
267 session->kxinfo = kx;
268 session->time_established = GNUNET_TIME_absolute_get ();
269 session->typemap_task =
270 GNUNET_SCHEDULER_add_now (&transmit_typemap_task, session);
271 GNUNET_assert (GNUNET_OK ==
272 GNUNET_CONTAINER_multihashmap_put (sessions, &peer->hashPubKey,
274 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
275 GNUNET_STATISTICS_set (GSC_stats, gettext_noop ("# entries in session map"),
276 GNUNET_CONTAINER_multihashmap_size (sessions),
278 GSC_CLIENTS_notify_clients_about_neighbour (peer, NULL, 0 /* FIXME: ATSI */ ,
279 NULL, session->tmap);
284 * Notify the given client about the session (client is new).
286 * @param cls the 'struct GSC_Client'
287 * @param key peer identity
288 * @param value the 'struct Session'
289 * @return GNUNET_OK (continue to iterate)
292 notify_client_about_session (void *cls, const GNUNET_HashCode * key,
295 struct GSC_Client *client = cls;
296 struct Session *session = value;
298 GSC_CLIENTS_notify_client_about_neighbour (client, &session->peer, NULL, 0, /* FIXME: ATS!? */
299 NULL, /* old TMAP: none */
306 * We have a new client, notify it about all current sessions.
308 * @param client the new client
311 GSC_SESSIONS_notify_client_about_sessions (struct GSC_Client *client)
313 /* notify new client about existing sessions */
314 GNUNET_CONTAINER_multihashmap_iterate (sessions, ¬ify_client_about_session,
320 * Try to perform a transmission on the given session. Will solicit
321 * additional messages if the 'sme' queue is not full enough.
323 * @param session session to transmit messages from
326 try_transmission (struct Session *session);
330 * Queue a request from a client for transmission to a particular peer.
332 * @param car request to queue; this handle is then shared between
333 * the caller (CLIENTS subsystem) and SESSIONS and must not
334 * be released by either until either 'GNUNET_SESSIONS_dequeue',
335 * 'GNUNET_SESSIONS_transmit' or 'GNUNET_CLIENTS_failed'
336 * have been invoked on it
339 GSC_SESSIONS_queue_request (struct GSC_ClientActiveRequest *car)
341 struct Session *session;
343 session = find_session (&car->target);
347 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
348 "Dropped client request for transmission (am disconnected)\n");
350 GNUNET_break (0); /* should have been rejected earlier */
351 GSC_CLIENTS_reject_request (car);
354 if (car->msize > GNUNET_CONSTANTS_MAX_ENCRYPTED_MESSAGE_SIZE)
357 GSC_CLIENTS_reject_request (car);
361 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
362 "Received client transmission request. queueing\n");
364 GNUNET_CONTAINER_DLL_insert (session->active_client_request_head,
365 session->active_client_request_tail, car);
366 try_transmission (session);
371 * Dequeue a request from a client from transmission to a particular peer.
373 * @param car request to dequeue; this handle will then be 'owned' by
374 * the caller (CLIENTS sysbsystem)
377 GSC_SESSIONS_dequeue_request (struct GSC_ClientActiveRequest *car)
382 memcmp (&car->target, &GSC_my_identity,
383 sizeof (struct GNUNET_PeerIdentity)))
385 s = find_session (&car->target);
386 GNUNET_assert (NULL != s);
387 GNUNET_CONTAINER_DLL_remove (s->active_client_request_head,
388 s->active_client_request_tail, car);
393 * Discard all expired active transmission requests from clients.
395 * @param session session to clean up
398 discard_expired_requests (struct Session *session)
400 struct GSC_ClientActiveRequest *pos;
401 struct GSC_ClientActiveRequest *nxt;
402 struct GNUNET_TIME_Absolute now;
404 now = GNUNET_TIME_absolute_get ();
406 nxt = session->active_client_request_head;
411 if ((pos->deadline.abs_value < now.abs_value) &&
412 (GNUNET_YES != pos->was_solicited))
414 GNUNET_STATISTICS_update (GSC_stats,
416 ("# messages discarded (expired prior to transmission)"),
418 GNUNET_CONTAINER_DLL_remove (session->active_client_request_head,
419 session->active_client_request_tail, pos);
420 GSC_CLIENTS_reject_request (pos);
427 * Solicit messages for transmission.
429 * @param session session to solict messages for
432 solicit_messages (struct Session *session)
434 struct GSC_ClientActiveRequest *car;
435 struct GSC_ClientActiveRequest *nxt;
438 discard_expired_requests (session);
440 nxt = session->active_client_request_head;
441 while (NULL != (car = nxt) )
444 if (so_size + car->msize > GNUNET_CONSTANTS_MAX_ENCRYPTED_MESSAGE_SIZE)
446 so_size += car->msize;
447 if (car->was_solicited == GNUNET_YES)
449 car->was_solicited = GNUNET_YES;
450 GSC_CLIENTS_solicit_request (car);
456 * Some messages were delayed (corked), but the timeout has now expired.
459 * @param cls 'struct Session' with the messages to transmit now
460 * @param tc scheduler context (unused)
463 pop_cork_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
465 struct Session *session = cls;
467 session->cork_task = GNUNET_SCHEDULER_NO_TASK;
468 try_transmission (session);
473 * Try to perform a transmission on the given session. Will solicit
474 * additional messages if the 'sme' queue is not full enough.
476 * @param session session to transmit messages from
479 try_transmission (struct Session *session)
481 struct SessionMessageEntry *pos;
483 struct GNUNET_TIME_Absolute now;
484 struct GNUNET_TIME_Absolute min_deadline;
486 if (GNUNET_YES != session->ready_to_transmit)
489 min_deadline = GNUNET_TIME_UNIT_FOREVER_ABS;
490 /* check 'ready' messages */
491 pos = session->sme_head;
492 while ((NULL != pos) &&
493 (msize + pos->size <= GNUNET_CONSTANTS_MAX_ENCRYPTED_MESSAGE_SIZE))
495 GNUNET_assert (pos->size < GNUNET_CONSTANTS_MAX_ENCRYPTED_MESSAGE_SIZE);
497 min_deadline = GNUNET_TIME_absolute_min (min_deadline, pos->deadline);
500 now = GNUNET_TIME_absolute_get ();
502 ((msize < GNUNET_CONSTANTS_MAX_ENCRYPTED_MESSAGE_SIZE / 2) &&
503 (min_deadline.abs_value > now.abs_value)))
505 /* not enough ready yet, try to solicit more */
506 solicit_messages (session);
509 /* if there is data to send, just not yet, make sure we do transmit
510 * it once the deadline is reached */
511 if (session->cork_task != GNUNET_SCHEDULER_NO_TASK)
512 GNUNET_SCHEDULER_cancel (session->cork_task);
514 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_absolute_get_remaining
515 (min_deadline), &pop_cork_task,
520 /* create plaintext buffer of all messages, encrypt and transmit */
522 static unsigned long long total_bytes;
523 static unsigned int total_msgs;
524 char pbuf[msize]; /* plaintext */
528 while ((NULL != (pos = session->sme_head)) && (used + pos->size <= msize))
530 memcpy (&pbuf[used], &pos[1], pos->size);
532 GNUNET_CONTAINER_DLL_remove (session->sme_head, session->sme_tail, pos);
535 /* compute average payload size */
540 /* 2^32 messages, wrap around... */
544 GNUNET_STATISTICS_set (GSC_stats, "# avg payload per encrypted message",
545 total_bytes / total_msgs, GNUNET_NO);
546 /* now actually transmit... */
547 session->ready_to_transmit = GNUNET_NO;
548 GSC_KX_encrypt_and_transmit (session->kxinfo, pbuf, used);
554 * Send a message to the neighbour now.
556 * @param cls the message
557 * @param key neighbour's identity
558 * @param value 'struct Neighbour' of the target
559 * @return always GNUNET_OK
562 do_send_message (void *cls, const GNUNET_HashCode * key, void *value)
564 const struct GNUNET_MessageHeader *hdr = cls;
565 struct Session *session = value;
566 struct SessionMessageEntry *m;
569 size = ntohs (hdr->size);
570 m = GNUNET_malloc (sizeof (struct SessionMessageEntry) + size);
571 memcpy (&m[1], hdr, size);
573 GNUNET_CONTAINER_DLL_insert (session->sme_head, session->sme_tail, m);
574 try_transmission (session);
580 * Broadcast a message to all neighbours.
582 * @param msg message to transmit
585 GSC_SESSIONS_broadcast (const struct GNUNET_MessageHeader *msg)
587 if (NULL == sessions)
589 GNUNET_CONTAINER_multihashmap_iterate (sessions, &do_send_message,
595 * Traffic is being solicited for the given peer. This means that the
596 * message queue on the transport-level (NEIGHBOURS subsystem) is now
597 * empty and it is now OK to transmit another (non-control) message.
599 * @param pid identity of peer ready to receive data
602 GSC_SESSIONS_solicit (const struct GNUNET_PeerIdentity *pid)
604 struct Session *session;
606 session = find_session (pid);
609 session->ready_to_transmit = GNUNET_YES;
610 try_transmission (session);
615 * Transmit a message to a particular peer.
617 * @param car original request that was queued and then solicited;
618 * this handle will now be 'owned' by the SESSIONS subsystem
619 * @param msg message to transmit
620 * @param cork is corking allowed?
623 GSC_SESSIONS_transmit (struct GSC_ClientActiveRequest *car,
624 const struct GNUNET_MessageHeader *msg, int cork)
626 struct Session *session;
627 struct SessionMessageEntry *sme;
630 session = find_session (&car->target);
633 msize = ntohs (msg->size);
634 sme = GNUNET_malloc (sizeof (struct SessionMessageEntry) + msize);
635 memcpy (&sme[1], msg, msize);
637 if (GNUNET_YES == cork)
639 GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_MAX_CORK_DELAY);
640 GNUNET_CONTAINER_DLL_insert_tail (session->sme_head, session->sme_tail, sme);
641 try_transmission (session);
646 * Helper function for GSC_SESSIONS_handle_client_iterate_peers.
648 * @param cls the 'struct GNUNET_SERVER_TransmitContext' to queue replies
649 * @param key identity of the connected peer
650 * @param value the 'struct Neighbour' for the peer
651 * @return GNUNET_OK (continue to iterate)
655 queue_connect_message (void *cls, const GNUNET_HashCode * key, void *value)
657 struct GNUNET_SERVER_TransmitContext *tc = cls;
658 struct Session *session = value;
659 struct ConnectNotifyMessage cnm;
661 /* FIXME: code duplication with clients... */
662 cnm.header.size = htons (sizeof (struct ConnectNotifyMessage));
663 cnm.header.type = htons (GNUNET_MESSAGE_TYPE_CORE_NOTIFY_CONNECT);
664 // FIXME: full ats...
665 cnm.ats_count = htonl (0);
666 cnm.peer = session->peer;
667 GNUNET_SERVER_transmit_context_append_message (tc, &cnm.header);
673 * Handle CORE_ITERATE_PEERS request. For this request type, the client
674 * does not have to have transmitted an INIT request. All current peers
675 * are returned, regardless of which message types they accept.
678 * @param client client sending the iteration request
679 * @param message iteration request message
682 GSC_SESSIONS_handle_client_iterate_peers (void *cls,
683 struct GNUNET_SERVER_Client *client,
684 const struct GNUNET_MessageHeader
687 struct GNUNET_MessageHeader done_msg;
688 struct GNUNET_SERVER_TransmitContext *tc;
690 tc = GNUNET_SERVER_transmit_context_create (client);
691 GNUNET_CONTAINER_multihashmap_iterate (sessions, &queue_connect_message, tc);
692 done_msg.size = htons (sizeof (struct GNUNET_MessageHeader));
693 done_msg.type = htons (GNUNET_MESSAGE_TYPE_CORE_ITERATE_PEERS_END);
694 GNUNET_SERVER_transmit_context_append_message (tc, &done_msg);
695 GNUNET_SERVER_transmit_context_run (tc, GNUNET_TIME_UNIT_FOREVER_REL);
700 * Handle CORE_PEER_CONNECTED request. Notify client about connection
701 * to the given neighbour. For this request type, the client does not
702 * have to have transmitted an INIT request. All current peers are
703 * returned, regardless of which message types they accept.
706 * @param client client sending the iteration request
707 * @param message iteration request message
710 GSC_SESSIONS_handle_client_have_peer (void *cls,
711 struct GNUNET_SERVER_Client *client,
712 const struct GNUNET_MessageHeader
715 struct GNUNET_MessageHeader done_msg;
716 struct GNUNET_SERVER_TransmitContext *tc;
717 const struct GNUNET_PeerIdentity *peer;
719 peer = (const struct GNUNET_PeerIdentity *) &message[1]; // YUCK!
720 tc = GNUNET_SERVER_transmit_context_create (client);
721 GNUNET_CONTAINER_multihashmap_get_multiple (sessions, &peer->hashPubKey,
722 &queue_connect_message, tc);
723 done_msg.size = htons (sizeof (struct GNUNET_MessageHeader));
724 done_msg.type = htons (GNUNET_MESSAGE_TYPE_CORE_ITERATE_PEERS_END);
725 GNUNET_SERVER_transmit_context_append_message (tc, &done_msg);
726 GNUNET_SERVER_transmit_context_run (tc, GNUNET_TIME_UNIT_FOREVER_REL);
731 * We've received a typemap message from a peer, update ours.
732 * Notifies clients about the session.
734 * @param peer peer this is about
735 * @param msg typemap update message
738 GSC_SESSIONS_set_typemap (const struct GNUNET_PeerIdentity *peer,
739 const struct GNUNET_MessageHeader *msg)
741 struct Session *session;
742 struct GSC_TypeMap *nmap;
744 nmap = GSC_TYPEMAP_get_from_message (msg);
746 return; /* malformed */
747 session = find_session (peer);
753 GSC_CLIENTS_notify_clients_about_neighbour (peer, NULL, 0, /* FIXME: ATS */
754 session->tmap, nmap);
755 GSC_TYPEMAP_destroy (session->tmap);
756 session->tmap = nmap;
761 * The given peer send a message of the specified type. Make sure the
762 * respective bit is set in its type-map and that clients are notified
765 * @param peer peer this is about
766 * @param type type of the message
769 GSC_SESSIONS_add_to_typemap (const struct GNUNET_PeerIdentity *peer,
772 struct Session *session;
773 struct GSC_TypeMap *nmap;
775 if (0 == memcmp (peer, &GSC_my_identity, sizeof (struct GNUNET_PeerIdentity)))
777 session = find_session (peer);
778 GNUNET_assert (NULL != session);
779 if (GNUNET_YES == GSC_TYPEMAP_test_match (session->tmap, &type, 1))
780 return; /* already in it */
781 nmap = GSC_TYPEMAP_extend (session->tmap, &type, 1);
782 GSC_CLIENTS_notify_clients_about_neighbour (peer, NULL, 0, /* FIXME: ATS */
783 session->tmap, nmap);
784 GSC_TYPEMAP_destroy (session->tmap);
785 session->tmap = nmap;
790 * Initialize sessions subsystem.
795 sessions = GNUNET_CONTAINER_multihashmap_create (128);
800 * Helper function for GSC_SESSIONS_handle_client_iterate_peers.
803 * @param key identity of the connected peer
804 * @param value the 'struct Session' for the peer
805 * @return GNUNET_OK (continue to iterate)
808 free_session_helper (void *cls, const GNUNET_HashCode * key, void *value)
810 struct Session *session = value;
812 GSC_SESSIONS_end (&session->peer);
818 * Shutdown sessions subsystem.
823 GNUNET_CONTAINER_multihashmap_iterate (sessions, &free_session_helper, NULL);
824 GNUNET_CONTAINER_multihashmap_destroy (sessions);
828 /* end of gnunet-service-core_sessions.c */