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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, session->sme_tail, sme);
199 GNUNET_SCHEDULER_cancel (session->typemap_task);
200 GSC_CLIENTS_notify_clients_about_neighbour (&session->peer, NULL,
201 0 /* FIXME: ATSI */ ,
202 session->tmap, NULL);
203 GNUNET_assert (GNUNET_YES ==
204 GNUNET_CONTAINER_multihashmap_remove (sessions,
208 GNUNET_STATISTICS_set (GSC_stats, gettext_noop ("# entries in session map"),
209 GNUNET_CONTAINER_multihashmap_size (sessions),
211 GSC_TYPEMAP_destroy (session->tmap);
212 session->tmap = NULL;
213 GNUNET_free (session);
218 * Transmit our current typemap message to the other peer.
219 * (Done periodically in case an update got lost).
221 * @param cls the 'struct Session*'
225 transmit_typemap_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
227 struct Session *session = cls;
228 struct GNUNET_MessageHeader *hdr;
229 struct GNUNET_TIME_Relative delay;
231 delay = TYPEMAP_FREQUENCY;
232 /* randomize a bit to avoid spont. sync */
234 GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, 1000);
235 session->typemap_task =
236 GNUNET_SCHEDULER_add_delayed (delay, &transmit_typemap_task, session);
237 GNUNET_STATISTICS_update (GSC_stats,
238 gettext_noop ("# type map refreshes sent"), 1,
240 hdr = GSC_TYPEMAP_compute_type_map_message ();
241 GSC_KX_encrypt_and_transmit (session->kxinfo, hdr, ntohs (hdr->size));
247 * Create a session, a key exchange was just completed.
249 * @param peer peer that is now connected
250 * @param kx key exchange that completed
253 GSC_SESSIONS_create (const struct GNUNET_PeerIdentity *peer,
254 struct GSC_KeyExchangeInfo *kx)
256 struct Session *session;
259 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Creating session for peer `%4s'\n",
262 session = GNUNET_malloc (sizeof (struct Session));
263 session->tmap = GSC_TYPEMAP_create ();
264 session->peer = *peer;
265 session->kxinfo = kx;
266 session->time_established = GNUNET_TIME_absolute_get ();
267 session->typemap_task =
268 GNUNET_SCHEDULER_add_now (&transmit_typemap_task, session);
269 GNUNET_assert (GNUNET_OK ==
270 GNUNET_CONTAINER_multihashmap_put (sessions, &peer->hashPubKey,
272 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
273 GNUNET_STATISTICS_set (GSC_stats, gettext_noop ("# entries in session map"),
274 GNUNET_CONTAINER_multihashmap_size (sessions),
276 GSC_CLIENTS_notify_clients_about_neighbour (peer, NULL, 0 /* FIXME: ATSI */ ,
277 NULL, session->tmap);
282 * Notify the given client about the session (client is new).
284 * @param cls the 'struct GSC_Client'
285 * @param key peer identity
286 * @param value the 'struct Session'
287 * @return GNUNET_OK (continue to iterate)
290 notify_client_about_session (void *cls, const GNUNET_HashCode * key,
293 struct GSC_Client *client = cls;
294 struct Session *session = value;
296 GSC_CLIENTS_notify_client_about_neighbour (client, &session->peer, NULL, 0, /* FIXME: ATS!? */
297 NULL, /* old TMAP: none */
304 * We have a new client, notify it about all current sessions.
306 * @param client the new client
309 GSC_SESSIONS_notify_client_about_sessions (struct GSC_Client *client)
311 /* notify new client about existing sessions */
312 GNUNET_CONTAINER_multihashmap_iterate (sessions, ¬ify_client_about_session,
318 * Try to perform a transmission on the given session. Will solicit
319 * additional messages if the 'sme' queue is not full enough.
321 * @param session session to transmit messages from
324 try_transmission (struct Session *session);
328 * Queue a request from a client for transmission to a particular peer.
330 * @param car request to queue; this handle is then shared between
331 * the caller (CLIENTS subsystem) and SESSIONS and must not
332 * be released by either until either 'GNUNET_SESSIONS_dequeue',
333 * 'GNUNET_SESSIONS_transmit' or 'GNUNET_CLIENTS_failed'
334 * have been invoked on it
337 GSC_SESSIONS_queue_request (struct GSC_ClientActiveRequest *car)
339 struct Session *session;
341 session = find_session (&car->target);
345 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
346 "Dropped client request for transmission (am disconnected)\n");
348 GNUNET_break (0); /* should have been rejected earlier */
349 GSC_CLIENTS_reject_request (car);
352 if (car->msize > GNUNET_CONSTANTS_MAX_ENCRYPTED_MESSAGE_SIZE)
355 GSC_CLIENTS_reject_request (car);
359 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
360 "Received client transmission request. queueing\n");
362 GNUNET_CONTAINER_DLL_insert (session->active_client_request_head,
363 session->active_client_request_tail, car);
364 try_transmission (session);
369 * Dequeue a request from a client from transmission to a particular peer.
371 * @param car request to dequeue; this handle will then be 'owned' by
372 * the caller (CLIENTS sysbsystem)
375 GSC_SESSIONS_dequeue_request (struct GSC_ClientActiveRequest *car)
380 memcmp (&car->target, &GSC_my_identity,
381 sizeof (struct GNUNET_PeerIdentity)))
383 s = find_session (&car->target);
384 GNUNET_assert (NULL != s);
385 GNUNET_CONTAINER_DLL_remove (s->active_client_request_head,
386 s->active_client_request_tail, car);
391 * Discard all expired active transmission requests from clients.
393 * @param session session to clean up
396 discard_expired_requests (struct Session *session)
398 struct GSC_ClientActiveRequest *pos;
399 struct GSC_ClientActiveRequest *nxt;
400 struct GNUNET_TIME_Absolute now;
402 now = GNUNET_TIME_absolute_get ();
404 nxt = session->active_client_request_head;
409 if ((pos->deadline.abs_value < now.abs_value) &&
410 (GNUNET_YES != pos->was_solicited))
412 GNUNET_STATISTICS_update (GSC_stats,
414 ("# messages discarded (expired prior to transmission)"),
416 GNUNET_CONTAINER_DLL_remove (session->active_client_request_head,
417 session->active_client_request_tail, pos);
418 GSC_CLIENTS_reject_request (pos);
425 * Solicit messages for transmission.
427 * @param session session to solict messages for
430 solicit_messages (struct Session *session)
432 struct GSC_ClientActiveRequest *car;
433 struct GSC_ClientActiveRequest *nxt;
436 discard_expired_requests (session);
438 nxt = session->active_client_request_head;
439 while (NULL != (car = nxt))
442 if (so_size + car->msize > GNUNET_CONSTANTS_MAX_ENCRYPTED_MESSAGE_SIZE)
444 so_size += car->msize;
445 if (car->was_solicited == GNUNET_YES)
447 car->was_solicited = GNUNET_YES;
448 GSC_CLIENTS_solicit_request (car);
454 * Some messages were delayed (corked), but the timeout has now expired.
457 * @param cls 'struct Session' with the messages to transmit now
458 * @param tc scheduler context (unused)
461 pop_cork_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
463 struct Session *session = cls;
465 session->cork_task = GNUNET_SCHEDULER_NO_TASK;
466 try_transmission (session);
471 * Try to perform a transmission on the given session. Will solicit
472 * additional messages if the 'sme' queue is not full enough.
474 * @param session session to transmit messages from
477 try_transmission (struct Session *session)
479 struct SessionMessageEntry *pos;
481 struct GNUNET_TIME_Absolute now;
482 struct GNUNET_TIME_Absolute min_deadline;
484 if (GNUNET_YES != session->ready_to_transmit)
487 min_deadline = GNUNET_TIME_UNIT_FOREVER_ABS;
488 /* check 'ready' messages */
489 pos = session->sme_head;
490 while ((NULL != pos) &&
491 (msize + pos->size <= GNUNET_CONSTANTS_MAX_ENCRYPTED_MESSAGE_SIZE))
493 GNUNET_assert (pos->size < GNUNET_CONSTANTS_MAX_ENCRYPTED_MESSAGE_SIZE);
495 min_deadline = GNUNET_TIME_absolute_min (min_deadline, pos->deadline);
498 now = GNUNET_TIME_absolute_get ();
500 ((msize < GNUNET_CONSTANTS_MAX_ENCRYPTED_MESSAGE_SIZE / 2) &&
501 (min_deadline.abs_value > now.abs_value)))
503 /* not enough ready yet, try to solicit more */
504 solicit_messages (session);
507 /* if there is data to send, just not yet, make sure we do transmit
508 * it once the deadline is reached */
509 if (session->cork_task != GNUNET_SCHEDULER_NO_TASK)
510 GNUNET_SCHEDULER_cancel (session->cork_task);
512 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_absolute_get_remaining
513 (min_deadline), &pop_cork_task,
518 /* create plaintext buffer of all messages, encrypt and transmit */
520 static unsigned long long total_bytes;
521 static unsigned int total_msgs;
522 char pbuf[msize]; /* plaintext */
526 while ((NULL != (pos = session->sme_head)) && (used + pos->size <= msize))
528 memcpy (&pbuf[used], &pos[1], pos->size);
530 GNUNET_CONTAINER_DLL_remove (session->sme_head, session->sme_tail, pos);
533 /* compute average payload size */
538 /* 2^32 messages, wrap around... */
542 GNUNET_STATISTICS_set (GSC_stats, "# avg payload per encrypted message",
543 total_bytes / total_msgs, GNUNET_NO);
544 /* now actually transmit... */
545 session->ready_to_transmit = GNUNET_NO;
546 GSC_KX_encrypt_and_transmit (session->kxinfo, pbuf, used);
552 * Send a message to the neighbour now.
554 * @param cls the message
555 * @param key neighbour's identity
556 * @param value 'struct Neighbour' of the target
557 * @return always GNUNET_OK
560 do_send_message (void *cls, const GNUNET_HashCode * key, void *value)
562 const struct GNUNET_MessageHeader *hdr = cls;
563 struct Session *session = value;
564 struct SessionMessageEntry *m;
567 size = ntohs (hdr->size);
568 m = GNUNET_malloc (sizeof (struct SessionMessageEntry) + size);
569 memcpy (&m[1], hdr, size);
571 GNUNET_CONTAINER_DLL_insert (session->sme_head, session->sme_tail, m);
572 try_transmission (session);
578 * Broadcast a message to all neighbours.
580 * @param msg message to transmit
583 GSC_SESSIONS_broadcast (const struct GNUNET_MessageHeader *msg)
585 if (NULL == sessions)
587 GNUNET_CONTAINER_multihashmap_iterate (sessions, &do_send_message,
593 * Traffic is being solicited for the given peer. This means that the
594 * message queue on the transport-level (NEIGHBOURS subsystem) is now
595 * empty and it is now OK to transmit another (non-control) message.
597 * @param pid identity of peer ready to receive data
600 GSC_SESSIONS_solicit (const struct GNUNET_PeerIdentity *pid)
602 struct Session *session;
604 session = find_session (pid);
607 session->ready_to_transmit = GNUNET_YES;
608 try_transmission (session);
613 * Transmit a message to a particular peer.
615 * @param car original request that was queued and then solicited;
616 * this handle will now be 'owned' by the SESSIONS subsystem
617 * @param msg message to transmit
618 * @param cork is corking allowed?
621 GSC_SESSIONS_transmit (struct GSC_ClientActiveRequest *car,
622 const struct GNUNET_MessageHeader *msg, int cork)
624 struct Session *session;
625 struct SessionMessageEntry *sme;
628 session = find_session (&car->target);
631 msize = ntohs (msg->size);
632 sme = GNUNET_malloc (sizeof (struct SessionMessageEntry) + msize);
633 memcpy (&sme[1], msg, msize);
635 if (GNUNET_YES == cork)
637 GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_MAX_CORK_DELAY);
638 GNUNET_CONTAINER_DLL_insert_tail (session->sme_head, session->sme_tail, sme);
639 try_transmission (session);
644 * Helper function for GSC_SESSIONS_handle_client_iterate_peers.
646 * @param cls the 'struct GNUNET_SERVER_TransmitContext' to queue replies
647 * @param key identity of the connected peer
648 * @param value the 'struct Neighbour' for the peer
649 * @return GNUNET_OK (continue to iterate)
653 queue_connect_message (void *cls, const GNUNET_HashCode * key, void *value)
655 struct GNUNET_SERVER_TransmitContext *tc = cls;
656 struct Session *session = value;
657 struct ConnectNotifyMessage cnm;
659 /* FIXME: code duplication with clients... */
660 cnm.header.size = htons (sizeof (struct ConnectNotifyMessage));
661 cnm.header.type = htons (GNUNET_MESSAGE_TYPE_CORE_NOTIFY_CONNECT);
662 // FIXME: full ats...
663 cnm.ats_count = htonl (0);
664 cnm.peer = session->peer;
665 GNUNET_SERVER_transmit_context_append_message (tc, &cnm.header);
671 * Handle CORE_ITERATE_PEERS request. For this request type, the client
672 * does not have to have transmitted an INIT request. All current peers
673 * are returned, regardless of which message types they accept.
676 * @param client client sending the iteration request
677 * @param message iteration request message
680 GSC_SESSIONS_handle_client_iterate_peers (void *cls,
681 struct GNUNET_SERVER_Client *client,
682 const struct GNUNET_MessageHeader
685 struct GNUNET_MessageHeader done_msg;
686 struct GNUNET_SERVER_TransmitContext *tc;
688 tc = GNUNET_SERVER_transmit_context_create (client);
689 GNUNET_CONTAINER_multihashmap_iterate (sessions, &queue_connect_message, tc);
690 done_msg.size = htons (sizeof (struct GNUNET_MessageHeader));
691 done_msg.type = htons (GNUNET_MESSAGE_TYPE_CORE_ITERATE_PEERS_END);
692 GNUNET_SERVER_transmit_context_append_message (tc, &done_msg);
693 GNUNET_SERVER_transmit_context_run (tc, GNUNET_TIME_UNIT_FOREVER_REL);
698 * Handle CORE_PEER_CONNECTED request. Notify client about connection
699 * to the given neighbour. For this request type, the client does not
700 * have to have transmitted an INIT request. All current peers are
701 * returned, regardless of which message types they accept.
704 * @param client client sending the iteration request
705 * @param message iteration request message
708 GSC_SESSIONS_handle_client_have_peer (void *cls,
709 struct GNUNET_SERVER_Client *client,
710 const struct GNUNET_MessageHeader
713 struct GNUNET_MessageHeader done_msg;
714 struct GNUNET_SERVER_TransmitContext *tc;
715 const struct GNUNET_PeerIdentity *peer;
717 peer = (const struct GNUNET_PeerIdentity *) &message[1]; // YUCK!
718 tc = GNUNET_SERVER_transmit_context_create (client);
719 GNUNET_CONTAINER_multihashmap_get_multiple (sessions, &peer->hashPubKey,
720 &queue_connect_message, tc);
721 done_msg.size = htons (sizeof (struct GNUNET_MessageHeader));
722 done_msg.type = htons (GNUNET_MESSAGE_TYPE_CORE_ITERATE_PEERS_END);
723 GNUNET_SERVER_transmit_context_append_message (tc, &done_msg);
724 GNUNET_SERVER_transmit_context_run (tc, GNUNET_TIME_UNIT_FOREVER_REL);
729 * We've received a typemap message from a peer, update ours.
730 * Notifies clients about the session.
732 * @param peer peer this is about
733 * @param msg typemap update message
736 GSC_SESSIONS_set_typemap (const struct GNUNET_PeerIdentity *peer,
737 const struct GNUNET_MessageHeader *msg)
739 struct Session *session;
740 struct GSC_TypeMap *nmap;
742 nmap = GSC_TYPEMAP_get_from_message (msg);
744 return; /* malformed */
745 session = find_session (peer);
751 GSC_CLIENTS_notify_clients_about_neighbour (peer, NULL, 0, /* FIXME: ATS */
752 session->tmap, nmap);
753 GSC_TYPEMAP_destroy (session->tmap);
754 session->tmap = nmap;
759 * The given peer send a message of the specified type. Make sure the
760 * respective bit is set in its type-map and that clients are notified
763 * @param peer peer this is about
764 * @param type type of the message
767 GSC_SESSIONS_add_to_typemap (const struct GNUNET_PeerIdentity *peer,
770 struct Session *session;
771 struct GSC_TypeMap *nmap;
773 if (0 == memcmp (peer, &GSC_my_identity, sizeof (struct GNUNET_PeerIdentity)))
775 session = find_session (peer);
776 GNUNET_assert (NULL != session);
777 if (GNUNET_YES == GSC_TYPEMAP_test_match (session->tmap, &type, 1))
778 return; /* already in it */
779 nmap = GSC_TYPEMAP_extend (session->tmap, &type, 1);
780 GSC_CLIENTS_notify_clients_about_neighbour (peer, NULL, 0, /* FIXME: ATS */
781 session->tmap, nmap);
782 GSC_TYPEMAP_destroy (session->tmap);
783 session->tmap = nmap;
788 * Initialize sessions subsystem.
793 sessions = GNUNET_CONTAINER_multihashmap_create (128);
798 * Helper function for GSC_SESSIONS_handle_client_iterate_peers.
801 * @param key identity of the connected peer
802 * @param value the 'struct Session' for the peer
803 * @return GNUNET_OK (continue to iterate)
806 free_session_helper (void *cls, const GNUNET_HashCode * key, void *value)
808 struct Session *session = value;
810 GSC_SESSIONS_end (&session->peer);
816 * Shutdown sessions subsystem.
821 GNUNET_CONTAINER_multihashmap_iterate (sessions, &free_session_helper, NULL);
822 GNUNET_CONTAINER_multihashmap_destroy (sessions);
826 /* end of gnunet-service-core_sessions.c */