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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;
175 session = find_session (pid);
179 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Destroying session for peer `%4s'\n",
180 GNUNET_i2s (&session->peer));
182 if (GNUNET_SCHEDULER_NO_TASK != session->cork_task)
184 GNUNET_SCHEDULER_cancel (session->cork_task);
185 session->cork_task = GNUNET_SCHEDULER_NO_TASK;
187 while (NULL != (car = session->active_client_request_head))
189 GNUNET_CONTAINER_DLL_remove (session->active_client_request_head,
190 session->active_client_request_tail, car);
191 GSC_CLIENTS_reject_request (car);
193 GNUNET_SCHEDULER_cancel (session->typemap_task);
194 GSC_CLIENTS_notify_clients_about_neighbour (&session->peer, NULL,
195 0 /* FIXME: ATSI */ ,
196 session->tmap, NULL);
197 GNUNET_assert (GNUNET_YES ==
198 GNUNET_CONTAINER_multihashmap_remove (sessions,
202 GNUNET_STATISTICS_set (GSC_stats, gettext_noop ("# entries in session map"),
203 GNUNET_CONTAINER_multihashmap_size (sessions),
205 GSC_TYPEMAP_destroy (session->tmap);
206 session->tmap = NULL;
207 GNUNET_free (session);
212 * Transmit our current typemap message to the other peer.
213 * (Done periodically in case an update got lost).
215 * @param cls the 'struct Session*'
219 transmit_typemap_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
221 struct Session *session = cls;
222 struct GNUNET_MessageHeader *hdr;
223 struct GNUNET_TIME_Relative delay;
225 delay = TYPEMAP_FREQUENCY;
226 /* randomize a bit to avoid spont. sync */
228 GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, 1000);
229 session->typemap_task =
230 GNUNET_SCHEDULER_add_delayed (delay, &transmit_typemap_task, session);
231 GNUNET_STATISTICS_update (GSC_stats,
232 gettext_noop ("# type map refreshes sent"), 1,
234 hdr = GSC_TYPEMAP_compute_type_map_message ();
235 GSC_KX_encrypt_and_transmit (session->kxinfo, hdr, ntohs (hdr->size));
241 * Create a session, a key exchange was just completed.
243 * @param peer peer that is now connected
244 * @param kx key exchange that completed
247 GSC_SESSIONS_create (const struct GNUNET_PeerIdentity *peer,
248 struct GSC_KeyExchangeInfo *kx)
250 struct Session *session;
253 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Creating session for peer `%4s'\n",
256 session = GNUNET_malloc (sizeof (struct Session));
257 session->tmap = GSC_TYPEMAP_create ();
258 session->peer = *peer;
259 session->kxinfo = kx;
260 session->time_established = GNUNET_TIME_absolute_get ();
261 session->typemap_task =
262 GNUNET_SCHEDULER_add_now (&transmit_typemap_task, session);
263 GNUNET_assert (GNUNET_OK ==
264 GNUNET_CONTAINER_multihashmap_put (sessions, &peer->hashPubKey,
266 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
267 GNUNET_STATISTICS_set (GSC_stats, gettext_noop ("# entries in session map"),
268 GNUNET_CONTAINER_multihashmap_size (sessions),
270 GSC_CLIENTS_notify_clients_about_neighbour (peer, NULL, 0 /* FIXME: ATSI */ ,
271 NULL, session->tmap);
276 * Notify the given client about the session (client is new).
278 * @param cls the 'struct GSC_Client'
279 * @param key peer identity
280 * @param value the 'struct Session'
281 * @return GNUNET_OK (continue to iterate)
284 notify_client_about_session (void *cls, const GNUNET_HashCode * key,
287 struct GSC_Client *client = cls;
288 struct Session *session = value;
290 GSC_CLIENTS_notify_client_about_neighbour (client, &session->peer, NULL, 0, /* FIXME: ATS!? */
291 NULL, /* old TMAP: none */
298 * We have a new client, notify it about all current sessions.
300 * @param client the new client
303 GSC_SESSIONS_notify_client_about_sessions (struct GSC_Client *client)
305 /* notify new client about existing sessions */
306 GNUNET_CONTAINER_multihashmap_iterate (sessions, ¬ify_client_about_session,
312 * Try to perform a transmission on the given session. Will solicit
313 * additional messages if the 'sme' queue is not full enough.
315 * @param session session to transmit messages from
318 try_transmission (struct Session *session);
322 * Queue a request from a client for transmission to a particular peer.
324 * @param car request to queue; this handle is then shared between
325 * the caller (CLIENTS subsystem) and SESSIONS and must not
326 * be released by either until either 'GNUNET_SESSIONS_dequeue',
327 * 'GNUNET_SESSIONS_transmit' or 'GNUNET_CLIENTS_failed'
328 * have been invoked on it
331 GSC_SESSIONS_queue_request (struct GSC_ClientActiveRequest *car)
333 struct Session *session;
335 session = find_session (&car->target);
339 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
340 "Dropped client request for transmission (am disconnected)\n");
342 GNUNET_break (0); /* should have been rejected earlier */
343 GSC_CLIENTS_reject_request (car);
346 if (car->msize > GNUNET_CONSTANTS_MAX_ENCRYPTED_MESSAGE_SIZE)
349 GSC_CLIENTS_reject_request (car);
353 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
354 "Received client transmission request. queueing\n");
356 GNUNET_CONTAINER_DLL_insert (session->active_client_request_head,
357 session->active_client_request_tail, car);
358 try_transmission (session);
363 * Dequeue a request from a client from transmission to a particular peer.
365 * @param car request to dequeue; this handle will then be 'owned' by
366 * the caller (CLIENTS sysbsystem)
369 GSC_SESSIONS_dequeue_request (struct GSC_ClientActiveRequest *car)
374 memcmp (&car->target, &GSC_my_identity,
375 sizeof (struct GNUNET_PeerIdentity)))
377 s = find_session (&car->target);
378 GNUNET_assert (NULL != s);
379 GNUNET_CONTAINER_DLL_remove (s->active_client_request_head,
380 s->active_client_request_tail, car);
385 * Discard all expired active transmission requests from clients.
387 * @param session session to clean up
390 discard_expired_requests (struct Session *session)
392 struct GSC_ClientActiveRequest *pos;
393 struct GSC_ClientActiveRequest *nxt;
394 struct GNUNET_TIME_Absolute now;
396 now = GNUNET_TIME_absolute_get ();
398 nxt = session->active_client_request_head;
403 if ((pos->deadline.abs_value < now.abs_value) &&
404 (GNUNET_YES != pos->was_solicited))
406 GNUNET_STATISTICS_update (GSC_stats,
408 ("# messages discarded (expired prior to transmission)"),
410 GNUNET_CONTAINER_DLL_remove (session->active_client_request_head,
411 session->active_client_request_tail, pos);
412 GSC_CLIENTS_reject_request (pos);
419 * Solicit messages for transmission.
421 * @param session session to solict messages for
424 solicit_messages (struct Session *session)
426 struct GSC_ClientActiveRequest *car;
429 discard_expired_requests (session);
431 for (car = session->active_client_request_head; NULL != car; car = car->next)
433 if (so_size + car->msize > GNUNET_CONSTANTS_MAX_ENCRYPTED_MESSAGE_SIZE)
435 so_size += car->msize;
436 if (car->was_solicited == GNUNET_YES)
438 car->was_solicited = GNUNET_YES;
439 GSC_CLIENTS_solicit_request (car);
445 * Some messages were delayed (corked), but the timeout has now expired.
448 * @param cls 'struct Session' with the messages to transmit now
449 * @param tc scheduler context (unused)
452 pop_cork_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
454 struct Session *session = cls;
456 session->cork_task = GNUNET_SCHEDULER_NO_TASK;
457 try_transmission (session);
462 * Try to perform a transmission on the given session. Will solicit
463 * additional messages if the 'sme' queue is not full enough.
465 * @param session session to transmit messages from
468 try_transmission (struct Session *session)
470 struct SessionMessageEntry *pos;
472 struct GNUNET_TIME_Absolute now;
473 struct GNUNET_TIME_Absolute min_deadline;
475 if (GNUNET_YES != session->ready_to_transmit)
478 min_deadline = GNUNET_TIME_UNIT_FOREVER_ABS;
479 /* check 'ready' messages */
480 pos = session->sme_head;
481 while ((NULL != pos) &&
482 (msize + pos->size <= GNUNET_CONSTANTS_MAX_ENCRYPTED_MESSAGE_SIZE))
484 GNUNET_assert (pos->size < GNUNET_CONSTANTS_MAX_ENCRYPTED_MESSAGE_SIZE);
486 min_deadline = GNUNET_TIME_absolute_min (min_deadline, pos->deadline);
489 now = GNUNET_TIME_absolute_get ();
491 ((msize < GNUNET_CONSTANTS_MAX_ENCRYPTED_MESSAGE_SIZE / 2) &&
492 (min_deadline.abs_value > now.abs_value)))
494 /* not enough ready yet, try to solicit more */
495 solicit_messages (session);
498 /* if there is data to send, just not yet, make sure we do transmit
499 * it once the deadline is reached */
500 if (session->cork_task != GNUNET_SCHEDULER_NO_TASK)
501 GNUNET_SCHEDULER_cancel (session->cork_task);
503 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_absolute_get_remaining
504 (min_deadline), &pop_cork_task,
509 /* create plaintext buffer of all messages, encrypt and transmit */
511 static unsigned long long total_bytes;
512 static unsigned int total_msgs;
513 char pbuf[msize]; /* plaintext */
517 while ((NULL != (pos = session->sme_head)) && (used + pos->size <= msize))
519 memcpy (&pbuf[used], &pos[1], pos->size);
521 GNUNET_CONTAINER_DLL_remove (session->sme_head, session->sme_tail, pos);
524 /* compute average payload size */
529 /* 2^32 messages, wrap around... */
533 GNUNET_STATISTICS_set (GSC_stats, "# avg payload per encrypted message",
534 total_bytes / total_msgs, GNUNET_NO);
535 /* now actually transmit... */
536 session->ready_to_transmit = GNUNET_NO;
537 GSC_KX_encrypt_and_transmit (session->kxinfo, pbuf, used);
543 * Send a message to the neighbour now.
545 * @param cls the message
546 * @param key neighbour's identity
547 * @param value 'struct Neighbour' of the target
548 * @return always GNUNET_OK
551 do_send_message (void *cls, const GNUNET_HashCode * key, void *value)
553 const struct GNUNET_MessageHeader *hdr = cls;
554 struct Session *session = value;
555 struct SessionMessageEntry *m;
558 size = ntohs (hdr->size);
559 m = GNUNET_malloc (sizeof (struct SessionMessageEntry) + size);
560 memcpy (&m[1], hdr, size);
562 GNUNET_CONTAINER_DLL_insert (session->sme_head, session->sme_tail, m);
563 try_transmission (session);
569 * Broadcast a message to all neighbours.
571 * @param msg message to transmit
574 GSC_SESSIONS_broadcast (const struct GNUNET_MessageHeader *msg)
576 if (NULL == sessions)
578 GNUNET_CONTAINER_multihashmap_iterate (sessions, &do_send_message,
584 * Traffic is being solicited for the given peer. This means that the
585 * message queue on the transport-level (NEIGHBOURS subsystem) is now
586 * empty and it is now OK to transmit another (non-control) message.
588 * @param pid identity of peer ready to receive data
591 GSC_SESSIONS_solicit (const struct GNUNET_PeerIdentity *pid)
593 struct Session *session;
595 session = find_session (pid);
598 session->ready_to_transmit = GNUNET_YES;
599 try_transmission (session);
604 * Transmit a message to a particular peer.
606 * @param car original request that was queued and then solicited;
607 * this handle will now be 'owned' by the SESSIONS subsystem
608 * @param msg message to transmit
609 * @param cork is corking allowed?
612 GSC_SESSIONS_transmit (struct GSC_ClientActiveRequest *car,
613 const struct GNUNET_MessageHeader *msg, int cork)
615 struct Session *session;
616 struct SessionMessageEntry *sme;
619 session = find_session (&car->target);
622 msize = ntohs (msg->size);
623 sme = GNUNET_malloc (sizeof (struct SessionMessageEntry) + msize);
624 memcpy (&sme[1], msg, msize);
626 if (GNUNET_YES == cork)
628 GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_MAX_CORK_DELAY);
629 GNUNET_CONTAINER_DLL_insert_tail (session->sme_head, session->sme_tail, sme);
630 try_transmission (session);
635 * Helper function for GSC_SESSIONS_handle_client_iterate_peers.
637 * @param cls the 'struct GNUNET_SERVER_TransmitContext' to queue replies
638 * @param key identity of the connected peer
639 * @param value the 'struct Neighbour' for the peer
640 * @return GNUNET_OK (continue to iterate)
644 queue_connect_message (void *cls, const GNUNET_HashCode * key, void *value)
646 struct GNUNET_SERVER_TransmitContext *tc = cls;
647 struct Session *session = value;
648 struct ConnectNotifyMessage cnm;
650 /* FIXME: code duplication with clients... */
651 cnm.header.size = htons (sizeof (struct ConnectNotifyMessage));
652 cnm.header.type = htons (GNUNET_MESSAGE_TYPE_CORE_NOTIFY_CONNECT);
653 // FIXME: full ats...
654 cnm.ats_count = htonl (0);
655 cnm.peer = session->peer;
656 GNUNET_SERVER_transmit_context_append_message (tc, &cnm.header);
662 * Handle CORE_ITERATE_PEERS request. For this request type, the client
663 * does not have to have transmitted an INIT request. All current peers
664 * are returned, regardless of which message types they accept.
667 * @param client client sending the iteration request
668 * @param message iteration request message
671 GSC_SESSIONS_handle_client_iterate_peers (void *cls,
672 struct GNUNET_SERVER_Client *client,
673 const struct GNUNET_MessageHeader
676 struct GNUNET_MessageHeader done_msg;
677 struct GNUNET_SERVER_TransmitContext *tc;
679 tc = GNUNET_SERVER_transmit_context_create (client);
680 GNUNET_CONTAINER_multihashmap_iterate (sessions, &queue_connect_message, tc);
681 done_msg.size = htons (sizeof (struct GNUNET_MessageHeader));
682 done_msg.type = htons (GNUNET_MESSAGE_TYPE_CORE_ITERATE_PEERS_END);
683 GNUNET_SERVER_transmit_context_append_message (tc, &done_msg);
684 GNUNET_SERVER_transmit_context_run (tc, GNUNET_TIME_UNIT_FOREVER_REL);
689 * Handle CORE_PEER_CONNECTED request. Notify client about connection
690 * to the given neighbour. For this request type, the client does not
691 * have to have transmitted an INIT request. All current peers are
692 * returned, regardless of which message types they accept.
695 * @param client client sending the iteration request
696 * @param message iteration request message
699 GSC_SESSIONS_handle_client_have_peer (void *cls,
700 struct GNUNET_SERVER_Client *client,
701 const struct GNUNET_MessageHeader
704 struct GNUNET_MessageHeader done_msg;
705 struct GNUNET_SERVER_TransmitContext *tc;
706 const struct GNUNET_PeerIdentity *peer;
708 peer = (const struct GNUNET_PeerIdentity *) &message[1]; // YUCK!
709 tc = GNUNET_SERVER_transmit_context_create (client);
710 GNUNET_CONTAINER_multihashmap_get_multiple (sessions, &peer->hashPubKey,
711 &queue_connect_message, tc);
712 done_msg.size = htons (sizeof (struct GNUNET_MessageHeader));
713 done_msg.type = htons (GNUNET_MESSAGE_TYPE_CORE_ITERATE_PEERS_END);
714 GNUNET_SERVER_transmit_context_append_message (tc, &done_msg);
715 GNUNET_SERVER_transmit_context_run (tc, GNUNET_TIME_UNIT_FOREVER_REL);
720 * We've received a typemap message from a peer, update ours.
721 * Notifies clients about the session.
723 * @param peer peer this is about
724 * @param msg typemap update message
727 GSC_SESSIONS_set_typemap (const struct GNUNET_PeerIdentity *peer,
728 const struct GNUNET_MessageHeader *msg)
730 struct Session *session;
731 struct GSC_TypeMap *nmap;
733 nmap = GSC_TYPEMAP_get_from_message (msg);
735 return; /* malformed */
736 session = find_session (peer);
742 GSC_CLIENTS_notify_clients_about_neighbour (peer, NULL, 0, /* FIXME: ATS */
743 session->tmap, nmap);
744 GSC_TYPEMAP_destroy (session->tmap);
745 session->tmap = nmap;
750 * The given peer send a message of the specified type. Make sure the
751 * respective bit is set in its type-map and that clients are notified
754 * @param peer peer this is about
755 * @param type type of the message
758 GSC_SESSIONS_add_to_typemap (const struct GNUNET_PeerIdentity *peer,
761 struct Session *session;
762 struct GSC_TypeMap *nmap;
764 if (0 == memcmp (peer, &GSC_my_identity, sizeof (struct GNUNET_PeerIdentity)))
766 session = find_session (peer);
767 GNUNET_assert (NULL != session);
768 if (GNUNET_YES == GSC_TYPEMAP_test_match (session->tmap, &type, 1))
769 return; /* already in it */
770 nmap = GSC_TYPEMAP_extend (session->tmap, &type, 1);
771 GSC_CLIENTS_notify_clients_about_neighbour (peer, NULL, 0, /* FIXME: ATS */
772 session->tmap, nmap);
773 GSC_TYPEMAP_destroy (session->tmap);
774 session->tmap = nmap;
779 * Initialize sessions subsystem.
784 sessions = GNUNET_CONTAINER_multihashmap_create (128);
789 * Helper function for GSC_SESSIONS_handle_client_iterate_peers.
792 * @param key identity of the connected peer
793 * @param value the 'struct Session' for the peer
794 * @return GNUNET_OK (continue to iterate)
797 free_session_helper (void *cls, const GNUNET_HashCode * key, void *value)
799 struct Session *session = value;
801 GSC_SESSIONS_end (&session->peer);
807 * Shutdown sessions subsystem.
812 GNUNET_CONTAINER_multihashmap_iterate (sessions, &free_session_helper, NULL);
813 GNUNET_CONTAINER_multihashmap_destroy (sessions);
817 /* end of gnunet-service-core_sessions.c */