2 This file is part of GNUnet.
3 (C) 2013 Christian Grothoff (and other contributing authors)
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22 * @file scalarproduct/gnunet-service-scalarproduct.c
23 * @brief scalarproduct service implementation
24 * @author Christian M. Fuchs
28 #include "gnunet_util_lib.h"
29 #include "gnunet_core_service.h"
30 #include "gnunet_mesh_service.h"
31 #include "gnunet_applications.h"
32 #include "gnunet_protocols.h"
33 #include "gnunet_scalarproduct_service.h"
34 #include "scalarproduct.h"
36 #define LOG(kind,...) GNUNET_log_from (kind, "scalarproduct", __VA_ARGS__)
38 ///////////////////////////////////////////////////////////////////////////////
39 // Service Structure Definitions
40 ///////////////////////////////////////////////////////////////////////////////
43 * state a session can be in
47 WAITING_FOR_BOBS_CONNECT,
48 MESSAGE_FROM_RESPONDING_CLIENT_RECEIVED,
49 WAITING_FOR_RESPONSE_FROM_SERVICE,
50 REQUEST_FROM_SERVICE_RECEIVED,
55 * role a peer in a session can assume
65 * A scalarproduct session which tracks:
67 * a request form the client to our final response.
69 * a request from a service to us(service).
74 * the role this peer has
79 * session information is kept in a DLL
81 struct ServiceSession *next;
84 * session information is kept in a DLL
86 struct ServiceSession *prev;
89 * (hopefully) unique transaction ID
91 struct GNUNET_HashCode key;
94 * state of the session
96 enum SessionState state;
99 * Alice or Bob's peerID
101 struct GNUNET_PeerIdentity peer;
104 * the client this request is related to
106 struct GNUNET_SERVER_Client * client;
109 * The message to send
111 struct GNUNET_MessageHeader * msg;
114 * how many elements we were supplied with from the client
116 uint16_t element_count;
119 * how many elements actually are used after applying the mask
121 uint16_t used_element_count;
124 * how many bytes the mask is long.
125 * just for convenience so we don't have to re-re-re calculate it each time
127 uint16_t mask_length;
130 * all the vector elements we received
135 * mask of which elements to check
137 unsigned char * mask;
140 * Public key of the remote service, only used by bob
142 gcry_sexp_t remote_pubkey;
145 * E(ai)(Bob) or ai(Alice) after applying the mask
150 * The computed scalar
155 * My transmit handle for the current message to a alice/bob
157 struct GNUNET_MESH_TransmitHandle * service_transmit_handle;
160 * My transmit handle for the current message to the client
162 struct GNUNET_SERVER_TransmitHandle * client_transmit_handle;
165 * tunnel-handle associated with our mesh handle
167 struct GNUNET_MESH_Tunnel * tunnel;
169 GNUNET_SCHEDULER_TaskIdentifier client_notification_task;
171 GNUNET_SCHEDULER_TaskIdentifier service_request_task;
174 ///////////////////////////////////////////////////////////////////////////////
176 ///////////////////////////////////////////////////////////////////////////////
180 * Handle to the core service (NULL until we've connected to it).
182 static struct GNUNET_MESH_Handle *my_mesh;
185 * The identity of this host.
187 static struct GNUNET_PeerIdentity me;
190 * Service's own public key represented as string
192 static unsigned char * my_pubkey_external;
195 * Service's own public key represented as string
197 static uint16_t my_pubkey_external_length = 0;
202 static gcry_mpi_t my_n;
205 * Service's own n^2 (kept for performance)
207 static gcry_mpi_t my_nsquare;
210 * Service's own public exponent
212 static gcry_mpi_t my_g;
215 * Service's own private multiplier
217 static gcry_mpi_t my_mu;
220 * Service's own private exponent
222 static gcry_mpi_t my_lambda;
225 * Service's offset for values that could possibly be negative but are plaintext for encryption.
227 static gcry_mpi_t my_offset;
230 * Head of our double linked list for client-requests sent to us.
231 * for all of these elements we calculate a scalar product with a remote peer
232 * split between service->service and client->service for simplicity
234 static struct ServiceSession * from_client_head;
236 * Tail of our double linked list for client-requests sent to us.
237 * for all of these elements we calculate a scalar product with a remote peer
238 * split between service->service and client->service for simplicity
240 static struct ServiceSession * from_client_tail;
243 * Head of our double linked list for service-requests sent to us.
244 * for all of these elements we help the requesting service in calculating a scalar product
245 * split between service->service and client->service for simplicity
247 static struct ServiceSession * from_service_head;
250 * Tail of our double linked list for service-requests sent to us.
251 * for all of these elements we help the requesting service in calculating a scalar product
252 * split between service->service and client->service for simplicity
254 static struct ServiceSession * from_service_tail;
257 * Certain events (callbacks for server & mesh operations) must not be queued after shutdown.
259 static int do_shutdown;
261 ///////////////////////////////////////////////////////////////////////////////
263 ///////////////////////////////////////////////////////////////////////////////
266 * Generates an Paillier private/public keyset and extracts the values using libgrcypt only
271 gcry_sexp_t gen_parms;
273 gcry_sexp_t tmp_sexp;
282 // we can still use the RSA keygen for generating p,q,n, but using e is pointless.
283 GNUNET_assert (0 == gcry_sexp_build (&gen_parms, &erroff,
284 "(genkey(rsa(nbits %d)(rsa-use-e 3:257)))",
287 GNUNET_assert (0 == gcry_pk_genkey (&key, gen_parms));
288 gcry_sexp_release (gen_parms);
290 // get n and d of our publickey as MPI
291 tmp_sexp = gcry_sexp_find_token (key, "n", 0);
292 GNUNET_assert (tmp_sexp);
293 my_n = gcry_sexp_nth_mpi (tmp_sexp, 1, GCRYMPI_FMT_USG);
294 gcry_sexp_release (tmp_sexp);
295 tmp_sexp = gcry_sexp_find_token (key, "p", 0);
296 GNUNET_assert (tmp_sexp);
297 p = gcry_sexp_nth_mpi (tmp_sexp, 1, GCRYMPI_FMT_USG);
298 gcry_sexp_release (tmp_sexp);
299 tmp_sexp = gcry_sexp_find_token (key, "q", 0);
300 GNUNET_assert (tmp_sexp);
301 q = gcry_sexp_nth_mpi (tmp_sexp, 1, GCRYMPI_FMT_USG);
302 gcry_sexp_release (key);
304 tmp1 = gcry_mpi_new (0);
305 tmp2 = gcry_mpi_new (0);
306 gcd = gcry_mpi_new (0);
307 my_g = gcry_mpi_new (0);
308 my_mu = gcry_mpi_new (0);
309 my_nsquare = gcry_mpi_new (0);
310 my_lambda = gcry_mpi_new (0);
313 // lambda = \frac{(p-1)*(q-1)}{gcd(p-1,q-1)}
314 gcry_mpi_sub_ui (tmp1, p, 1);
315 gcry_mpi_sub_ui (tmp2, q, 1);
316 gcry_mpi_gcd (gcd, tmp1, tmp2);
317 gcry_mpi_set (my_lambda, tmp1);
318 gcry_mpi_mul (my_lambda, my_lambda, tmp2);
319 gcry_mpi_div (my_lambda, NULL, my_lambda, gcd, 0);
322 gcry_mpi_mul (my_nsquare, my_n, my_n);
328 gcry_mpi_randomize (my_g, KEYBITS * 2, GCRY_WEAK_RANDOM);
329 // g must be smaller than n^2
330 if (0 >= gcry_mpi_cmp (my_g, my_nsquare))
333 // g must have gcd == 1 with n^2
334 gcry_mpi_gcd (gcd, my_g, my_nsquare);
336 while (gcry_mpi_cmp_ui (gcd, 1));
338 // is this a valid g?
339 // if so, gcd(((g^lambda mod n^2)-1 )/n, n) = 1
340 gcry_mpi_powm (tmp1, my_g, my_lambda, my_nsquare);
341 gcry_mpi_sub_ui (tmp1, tmp1, 1);
342 gcry_mpi_div (tmp1, NULL, tmp1, my_n, 0);
343 gcry_mpi_gcd (gcd, tmp1, my_n);
345 while (gcry_mpi_cmp_ui (gcd, 1));
347 // calculate our mu based on g and n.
348 // mu = (((g^lambda mod n^2)-1 )/n)^-1 mod n
349 gcry_mpi_invm (my_mu, tmp1, my_n);
351 GNUNET_assert (0 == gcry_sexp_build (&key, &erroff,
352 "(public-key (paillier (n %M)(g %M)))",
355 // get the length of this sexpression
356 my_pubkey_external_length = gcry_sexp_sprint (key,
361 GNUNET_assert (my_pubkey_external_length > 0);
362 my_pubkey_external = GNUNET_malloc (my_pubkey_external_length);
364 // convert the sexpression to canonical format
365 gcry_sexp_sprint (key,
368 my_pubkey_external_length);
370 gcry_sexp_release (key);
372 // offset has to be sufficiently small to allow computation of:
373 // m1+m2 mod n == (S + a) + (S + b) mod n,
374 // if we have more complex operations, this factor needs to be lowered
375 my_offset = gcry_mpi_new(KEYBITS/3);
376 gcry_mpi_set_bit(my_offset, KEYBITS/3);
378 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, _ ("Generated key set with key length %d bits.\n"), KEYBITS);
383 * If target != size, move target bytes to the
384 * end of the size-sized buffer and zero out the
385 * first target-size bytes.
387 * @param buf original buffer
388 * @param size number of bytes in the buffer
389 * @param target target size of the buffer
392 adjust (unsigned char *buf, size_t size, size_t target)
396 memmove (&buf[target - size], buf, size);
397 memset (buf, 0, target - size);
403 * encrypts an element using the paillier crypto system
405 * @param c ciphertext (output)
407 * @param g the public base
408 * @param n the module from which which r is chosen (Z*_n)
409 * @param n_square the module for encryption, for performance reasons.
412 encrypt_element (gcry_mpi_t c, gcry_mpi_t m, gcry_mpi_t g, gcry_mpi_t n, gcry_mpi_t n_square)
416 GNUNET_assert (tmp = gcry_mpi_new (0));
418 while (0 >= gcry_mpi_cmp_ui (tmp, 1))
420 gcry_mpi_randomize (tmp, KEYBITS / 3, GCRY_WEAK_RANDOM);
421 // r must be 1 < r < n
424 gcry_mpi_powm (c, g, m, n_square);
425 gcry_mpi_powm (tmp, tmp, n, n_square);
426 gcry_mpi_mulm (c, tmp, c, n_square);
428 gcry_mpi_release (tmp);
432 * decrypts an element using the paillier crypto system
434 * @param m plaintext (output)
435 * @param c the ciphertext
436 * @param mu the modifier to correct encryption
437 * @param lambda the private exponent
438 * @param n the outer module for decryption
439 * @param n_square the inner module for decryption
442 decrypt_element (gcry_mpi_t m, gcry_mpi_t c, gcry_mpi_t mu, gcry_mpi_t lambda, gcry_mpi_t n, gcry_mpi_t n_square)
444 gcry_mpi_powm (m, c, lambda, n_square);
445 gcry_mpi_sub_ui (m, m, 1);
446 gcry_mpi_div (m, NULL, m, n, 0);
447 gcry_mpi_mulm (m, m, mu, n);
452 * computes the square sum over a vector of a given length.
454 * @param vector the vector to encrypt
455 * @param length the length of the vector
456 * @return an MPI value containing the calculated sum, never NULL
459 compute_square_sum (gcry_mpi_t * vector, uint16_t length)
465 GNUNET_assert (sum = gcry_mpi_new (0));
466 GNUNET_assert (elem = gcry_mpi_new (0));
468 // calculare E(sum (ai ^ 2), publickey)
469 for (i = 0; i < length; i++)
471 gcry_mpi_mul (elem, vector[i], vector[i]);
472 gcry_mpi_add (sum, sum, elem);
474 gcry_mpi_release (elem);
481 * Primitive callback for copying over a message, as they
482 * usually are too complex to be handled in the callback itself.
483 * clears a session-callback, if a session was handed over and the transmit handle was stored
485 * @param cls the message object
486 * @param size the size of the buffer we got
487 * @param buf the buffer to copy the message to
488 * @return 0 if we couldn't copy, else the size copied over
491 do_send_message (void *cls, size_t size, void *buf)
493 struct ServiceSession * session = cls;
498 if (ntohs (session->msg->size) == size)
500 memcpy (buf, session->msg, size);
504 if (GNUNET_MESSAGE_TYPE_SCALARPRODUCT_SERVICE_TO_CLIENT == ntohs(session->msg->type)){
505 session->state = FINALIZED;
506 session->client_transmit_handle = NULL;
509 session->service_transmit_handle = NULL;
511 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
512 "Sent a message of type %hu.\n",
513 ntohs (session->msg->type));
514 GNUNET_free(session->msg);
522 * initializes a new vector with fresh MPI values (=0) of a given length
524 * @param length of the vector to create
525 * @return the initialized vector, never NULL
528 initialize_mpi_vector (uint16_t length)
531 gcry_mpi_t * output = GNUNET_malloc (sizeof (gcry_mpi_t) * length);
533 for (i = 0; i < length; i++)
534 GNUNET_assert (NULL != (output[i] = gcry_mpi_new (0)));
540 * permutes an MPI vector according to the given permutation vector
542 * @param vector the vector to permuted
543 * @param perm the permutation to use
544 * @param length the length of the vectors
545 * @return the permuted vector (same as input), never NULL
548 permute_vector (gcry_mpi_t * vector,
552 gcry_mpi_t tmp[length];
555 GNUNET_assert (length > 0);
558 memcpy (tmp, vector, length * sizeof (gcry_mpi_t));
560 // permute vector according to given
561 for (i = 0; i < length; i++)
562 vector[i] = tmp[perm[i]];
569 * Populate a vector with random integer values and convert them to
571 * @param length the length of the vector we must generate
572 * @return an array of MPI values with random values
575 generate_random_vector (uint16_t length)
577 gcry_mpi_t * random_vector;
581 random_vector = initialize_mpi_vector (length);
582 for (i = 0; i < length; i++)
584 value = (int32_t) GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, UINT32_MAX);
586 // long to gcry_mpi_t
588 gcry_mpi_sub_ui (random_vector[i],
592 random_vector[i] = gcry_mpi_set_ui (random_vector[i], value);
595 return random_vector;
600 * Finds a not terminated client/service session in the
601 * given DLL based on session key, element count and state.
603 * @param tail - the tail of the DLL
604 * @param my - the session to compare it to
605 * @return a pointer to a matching session,
608 static struct ServiceSession *
609 find_matching_session (struct ServiceSession * tail,
610 const struct GNUNET_HashCode * key,
611 uint16_t element_count,
612 enum SessionState * state,
613 const struct GNUNET_PeerIdentity * peerid)
615 struct ServiceSession * curr;
617 for (curr = tail; NULL != curr; curr = curr->prev)
619 // if the key matches, and the element_count is same
620 if ((!memcmp (&curr->key, key, sizeof (struct GNUNET_HashCode)))
621 && (curr->element_count == element_count))
623 // if incoming state is NULL OR is same as state of the queued request
624 if ((NULL == state) || (curr->state == *state))
626 // if peerid is NULL OR same as the peer Id in the queued request
628 || (!memcmp (&curr->peer, peerid, sizeof (struct GNUNET_PeerIdentity))))
629 // matches and is not an already terminated session
640 free_session (struct ServiceSession * session)
646 for (i = 0; i < session->used_element_count; i++)
647 gcry_mpi_release (session->a[i]);
649 GNUNET_free (session->a);
651 if (session->product)
652 gcry_mpi_release (session->product);
654 if (session->remote_pubkey)
655 gcry_sexp_release (session->remote_pubkey);
657 GNUNET_free_non_null (session->vector);
658 GNUNET_free (session);
660 ///////////////////////////////////////////////////////////////////////////////
661 // Event and Message Handlers
662 ///////////////////////////////////////////////////////////////////////////////
665 * A client disconnected.
667 * Remove the associated session(s), release datastructures
668 * and cancel pending outgoing transmissions to the client.
669 * if the session has not yet completed, we also cancel Alice's request to Bob.
671 * @param cls closure, NULL
672 * @param client identification of the client
675 handle_client_disconnect (void *cls,
676 struct GNUNET_SERVER_Client *client)
678 struct ServiceSession *session;
680 session = GNUNET_SERVER_client_get_user_context (client, struct ServiceSession);
683 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
684 _ ("Client (%p) disconnected from us.\n"), client);
685 GNUNET_CONTAINER_DLL_remove (from_client_head, from_client_tail, session);
687 if (!(session->role == BOB && session->state == FINALIZED))
689 //we MUST terminate any client message underway
690 if (session->service_transmit_handle && session->tunnel)
691 GNUNET_MESH_notify_transmit_ready_cancel (session->service_transmit_handle);
692 if (session->tunnel && session->state == WAITING_FOR_RESPONSE_FROM_SERVICE)
693 GNUNET_MESH_tunnel_destroy (session->tunnel);
695 if (GNUNET_SCHEDULER_NO_TASK != session->client_notification_task)
697 GNUNET_SCHEDULER_cancel (session->client_notification_task);
698 session->client_notification_task = GNUNET_SCHEDULER_NO_TASK;
700 if (GNUNET_SCHEDULER_NO_TASK != session->service_request_task)
702 GNUNET_SCHEDULER_cancel (session->service_request_task);
703 session->service_request_task = GNUNET_SCHEDULER_NO_TASK;
705 if (NULL != session->client_transmit_handle)
707 GNUNET_SERVER_notify_transmit_ready_cancel (session->client_transmit_handle);
708 session->client_transmit_handle = NULL;
710 free_session (session);
715 * Notify the client that the session has succeeded or failed completely.
716 * This message gets sent to
717 * * alice's client if bob disconnected or to
718 * * bob's client if the operation completed or alice disconnected
720 * @param client_session the associated client session
721 * @return GNUNET_NO, if we could not notify the client
722 * GNUNET_YES if we notified it.
725 prepare_client_end_notification (void * cls,
726 const struct GNUNET_SCHEDULER_TaskContext * tc)
728 struct ServiceSession * session = cls;
729 struct GNUNET_SCALARPRODUCT_client_response * msg;
731 session->client_notification_task = GNUNET_SCHEDULER_NO_TASK;
733 msg = GNUNET_new (struct GNUNET_SCALARPRODUCT_client_response);
734 msg->header.type = htons (GNUNET_MESSAGE_TYPE_SCALARPRODUCT_SERVICE_TO_CLIENT);
735 memcpy (&msg->key, &session->key, sizeof (struct GNUNET_HashCode));
736 memcpy (&msg->peer, &session->peer, sizeof ( struct GNUNET_PeerIdentity));
737 msg->header.size = htons (sizeof (struct GNUNET_SCALARPRODUCT_client_response));
738 // 0 size and the first char in the product is 0, which should never be zero if encoding is used.
739 msg->product_length = htonl (0);
742 session->msg = &msg->header;
744 //transmit this message to our client
745 session->client_transmit_handle =
746 GNUNET_SERVER_notify_transmit_ready (session->client,
747 sizeof (struct GNUNET_SCALARPRODUCT_client_response),
748 GNUNET_TIME_UNIT_FOREVER_REL,
752 // if we could not even queue our request, something is wrong
753 if ( ! session->client_transmit_handle)
755 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Could not send message to client (%p)! This is OK if it was disconnected beforehand already.\n"), session->client);
756 // usually gets freed by do_send_message
757 GNUNET_free (msg_obj);
761 GNUNET_log (GNUNET_ERROR_TYPE_INFO, _ ("Sending session-end notification to client (%p) for session %s\n"), &session->client, GNUNET_h2s (&session->key));
768 * generates the response message to be sent to alice after computing
769 * the values (1), (2), S and S'
770 * (1)[]: $E_A(a_{pi(i)}) times E_A(- r_{pi(i)} - b_{pi(i)}) &= E_A(a_{pi(i)} - r_{pi(i)} - b_{pi(i)})$
771 * (2)[]: $E_A(a_{pi'(i)}) times E_A(- r_{pi'(i)}) &= E_A(a_{pi'(i)} - r_{pi'(i)})$
772 * S: $S := E_A(sum (r_i + b_i)^2)$
773 * S': $S' := E_A(sum r_i^2)$
775 * @param r (1)[]: $E_A(a_{pi(i)}) times E_A(- r_{pi(i)} - b_{pi(i)}) &= E_A(a_{pi(i)} - r_{pi(i)} - b_{pi(i)})$
776 * @param r_prime (2)[]: $E_A(a_{pi'(i)}) times E_A(- r_{pi'(i)}) &= E_A(a_{pi'(i)} - r_{pi'(i)})$
777 * @param s S: $S := E_A(sum (r_i + b_i)^2)$
778 * @param s_prime S': $S' := E_A(sum r_i^2)$
779 * @param request the associated requesting session with alice
780 * @param response the associated responder session with bob's client
781 * @return GNUNET_SYSERR if the function was called with NULL parameters or if there was an error
782 * GNUNET_NO if we could not send our message
783 * GNUNET_OK if the operation succeeded
786 prepare_service_response (gcry_mpi_t * r,
787 gcry_mpi_t * r_prime,
790 struct ServiceSession * request,
791 struct ServiceSession * response)
793 struct GNUNET_SCALARPRODUCT_service_response * msg;
794 uint16_t msg_length = 0;
795 unsigned char * current = NULL;
796 unsigned char * element_exported = NULL;
797 size_t element_length = 0;
800 msg_length = sizeof (struct GNUNET_SCALARPRODUCT_service_response)
801 + 2 * request->used_element_count * PAILLIER_ELEMENT_LENGTH // kp, kq
802 + 2 * PAILLIER_ELEMENT_LENGTH; // s, stick
804 msg = GNUNET_malloc (msg_length);
806 msg->header.type = htons (GNUNET_MESSAGE_TYPE_SCALARPRODUCT_BOB_TO_ALICE);
807 msg->header.size = htons (msg_length);
808 msg->element_count = htons (request->element_count);
809 msg->used_element_count = htons (request->used_element_count);
810 memcpy (&msg->key, &request->key, sizeof (struct GNUNET_HashCode));
811 current = (unsigned char *) &msg[1];
813 // 4 times the same logics with slight variations.
814 // doesn't really justify having 2 functions for that
815 // so i put it into blocks to enhance readability
818 element_exported = GNUNET_malloc (PAILLIER_ELEMENT_LENGTH);
819 GNUNET_assert (0 == gcry_mpi_print (GCRYMPI_FMT_USG,
820 element_exported, PAILLIER_ELEMENT_LENGTH,
823 adjust (element_exported, element_length, PAILLIER_ELEMENT_LENGTH);
824 memcpy (current, element_exported, PAILLIER_ELEMENT_LENGTH);
825 GNUNET_free (element_exported);
826 current += PAILLIER_ELEMENT_LENGTH;
831 element_exported = GNUNET_malloc (PAILLIER_ELEMENT_LENGTH);
832 GNUNET_assert (0 == gcry_mpi_print (GCRYMPI_FMT_USG,
833 element_exported, PAILLIER_ELEMENT_LENGTH,
836 adjust (element_exported, element_length, PAILLIER_ELEMENT_LENGTH);
837 memcpy (current, element_exported, PAILLIER_ELEMENT_LENGTH);
838 GNUNET_free (element_exported);
839 current += PAILLIER_ELEMENT_LENGTH;
843 for (i = 0; i < request->used_element_count; i++)
845 element_exported = GNUNET_malloc (PAILLIER_ELEMENT_LENGTH);
846 GNUNET_assert (0 == gcry_mpi_print (GCRYMPI_FMT_USG,
847 element_exported, PAILLIER_ELEMENT_LENGTH,
850 adjust (element_exported, element_length, PAILLIER_ELEMENT_LENGTH);
851 memcpy (current, element_exported, PAILLIER_ELEMENT_LENGTH);
852 GNUNET_free (element_exported);
853 current += PAILLIER_ELEMENT_LENGTH;
858 for (i = 0; i < request->used_element_count; i++)
860 element_exported = GNUNET_malloc (PAILLIER_ELEMENT_LENGTH);
861 GNUNET_assert (0 == gcry_mpi_print (GCRYMPI_FMT_USG,
862 element_exported, PAILLIER_ELEMENT_LENGTH,
865 adjust (element_exported, element_length, PAILLIER_ELEMENT_LENGTH);
866 memcpy (current, element_exported, PAILLIER_ELEMENT_LENGTH);
867 GNUNET_free (element_exported);
868 current += PAILLIER_ELEMENT_LENGTH;
871 if (GNUNET_SERVER_MAX_MESSAGE_SIZE >= msg_length)
873 struct MessageObject * msg_obj;
875 msg_obj = GNUNET_new (struct MessageObject);
876 msg_obj->msg = (struct GNUNET_MessageHeader *) msg;
877 msg_obj->transmit_handle = (void *) &request->service_transmit_handle; //and reset the transmit handle
878 request->service_transmit_handle =
879 GNUNET_MESH_notify_transmit_ready (request->tunnel,
881 GNUNET_TIME_UNIT_FOREVER_REL,
885 // we don't care if it could be send or not. either way, the session is over for us.
886 request->state = FINALIZED;
887 response->state = FINALIZED;
891 // TODO FEATURE: fallback to fragmentation, in case the message is too long
892 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Message too large, fragmentation is currently not supported!)\n"));
895 //disconnect our client
896 if ( ! request->service_transmit_handle)
898 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, _ ("Could not send service-response message via mesh!)\n"));
899 GNUNET_CONTAINER_DLL_remove (from_client_head, from_client_tail, response);
901 response->client_notification_task =
902 GNUNET_SCHEDULER_add_now (&prepare_client_end_notification,
913 * (1)[]: $E_A(a_{\pi(i)}) \otimes E_A(- r_{\pi(i)} - b_{\pi(i)}) &= E_A(a_{\pi(i)} - r_{\pi(i)} - b_{\pi(i)})$
914 * (2)[]: $E_A(a_{\pi'(i)}) \otimes E_A(- r_{\pi'(i)}) &= E_A(a_{\pi'(i)} - r_{\pi'(i)})$
915 * S: $S := E_A(\sum (r_i + b_i)^2)$
916 * S': $S' := E_A(\sum r_i^2)$
918 * @param request the requesting session + bob's requesting peer
919 * @param response the responding session + bob's client handle
920 * @return GNUNET_SYSERR if the computation failed
921 * GNUNET_OK if everything went well.
924 compute_service_response (struct ServiceSession * request,
925 struct ServiceSession * response)
929 int ret = GNUNET_SYSERR;
933 gcry_mpi_t * rand = NULL;
934 gcry_mpi_t * r = NULL;
935 gcry_mpi_t * r_prime = NULL;
938 gcry_mpi_t * a_pi_prime;
940 gcry_mpi_t * rand_pi;
941 gcry_mpi_t * rand_pi_prime;
943 gcry_mpi_t s_prime = NULL;
944 gcry_mpi_t remote_n = NULL;
945 gcry_mpi_t remote_nsquare;
946 gcry_mpi_t remote_g = NULL;
950 count = request->used_element_count;
952 b = GNUNET_malloc (sizeof (gcry_mpi_t) * count);
953 a_pi = GNUNET_malloc (sizeof (gcry_mpi_t) * count);
954 b_pi = GNUNET_malloc (sizeof (gcry_mpi_t) * count);
955 a_pi_prime = GNUNET_malloc (sizeof (gcry_mpi_t) * count);
956 rand_pi = GNUNET_malloc (sizeof (gcry_mpi_t) * count);
957 rand_pi_prime = GNUNET_malloc (sizeof (gcry_mpi_t) * count);
959 // convert responder session to from long to mpi
960 for (i = 0, j = 0; i < response->element_count && j < count; i++)
962 if (request->mask[i / 8] & (1 << (i % 8)))
964 value = response->vector[i] >= 0 ? response->vector[i] : -response->vector[i];
965 // long to gcry_mpi_t
966 if (0 > response->vector[i])
968 b[j] = gcry_mpi_new (0);
969 gcry_mpi_sub_ui (b[j], b[j], value);
973 b[j] = gcry_mpi_set_ui (NULL, value);
978 GNUNET_free (response->vector);
979 response->vector = NULL;
981 tmp_exp = gcry_sexp_find_token (request->remote_pubkey, "n", 0);
985 gcry_sexp_release (request->remote_pubkey);
986 request->remote_pubkey = NULL;
989 remote_n = gcry_sexp_nth_mpi (tmp_exp, 1, GCRYMPI_FMT_USG);
993 gcry_sexp_release (tmp_exp);
996 remote_nsquare = gcry_mpi_new (KEYBITS + 1);
997 gcry_mpi_mul (remote_nsquare, remote_n, remote_n);
998 gcry_sexp_release (tmp_exp);
999 tmp_exp = gcry_sexp_find_token (request->remote_pubkey, "g", 0);
1000 gcry_sexp_release (request->remote_pubkey);
1001 request->remote_pubkey = NULL;
1004 GNUNET_break_op (0);
1005 gcry_mpi_release (remote_n);
1008 remote_g = gcry_sexp_nth_mpi (tmp_exp, 1, GCRYMPI_FMT_USG);
1012 gcry_mpi_release (remote_n);
1013 gcry_sexp_release (tmp_exp);
1016 gcry_sexp_release (tmp_exp);
1018 // generate r, p and q
1019 rand = generate_random_vector (count);
1020 p = GNUNET_CRYPTO_random_permute (GNUNET_CRYPTO_QUALITY_WEAK, count);
1021 q = GNUNET_CRYPTO_random_permute (GNUNET_CRYPTO_QUALITY_WEAK, count);
1022 //initialize the result vectors
1023 r = initialize_mpi_vector (count);
1024 r_prime = initialize_mpi_vector (count);
1026 // copy the REFERNCES of a, b and r into aq and bq. we will not change
1027 // those values, thus we can work with the references
1028 memcpy (a_pi, request->a, sizeof (gcry_mpi_t) * count);
1029 memcpy (a_pi_prime, request->a, sizeof (gcry_mpi_t) * count);
1030 memcpy (b_pi, b, sizeof (gcry_mpi_t) * count);
1031 memcpy (rand_pi, rand, sizeof (gcry_mpi_t) * count);
1032 memcpy (rand_pi_prime, rand, sizeof (gcry_mpi_t) * count);
1034 // generate p and q permutations for a, b and r
1035 GNUNET_assert (permute_vector (a_pi, p, count));
1036 GNUNET_assert (permute_vector (b_pi, p, count));
1037 GNUNET_assert (permute_vector (rand_pi, p, count));
1038 GNUNET_assert (permute_vector (a_pi_prime, q, count));
1039 GNUNET_assert (permute_vector (rand_pi_prime, q, count));
1041 // encrypt the element
1042 // for the sake of readability I decided to have dedicated permutation
1043 // vectors, which get rid of all the lookups in p/q.
1044 // however, ap/aq are not absolutely necessary but are just abstraction
1045 // Calculate Kp = E(S + a_pi) (+) E(S - r_pi - b_pi)
1046 for (i = 0; i < count; i++)
1048 // E(S - r_pi - b_pi)
1049 gcry_mpi_sub (r[i], my_offset, rand_pi[i]);
1050 gcry_mpi_sub (r[i], r[i], b_pi[i]);
1051 encrypt_element (r[i], r[i], remote_g, remote_n, remote_nsquare);
1053 // E(S - r_pi - b_pi) * E(S + a_pi) == E(2*S + a - r - b)
1054 gcry_mpi_mulm (r[i], r[i], a_pi[i], remote_nsquare);
1058 GNUNET_free (rand_pi);
1060 // Calculate Kq = E(S + a_qi) (+) E(S - r_qi)
1061 for (i = 0; i < count; i++)
1064 gcry_mpi_sub (r_prime[i], my_offset, rand_pi_prime[i]);
1065 encrypt_element (r_prime[i], r_prime[i], remote_g, remote_n, remote_nsquare);
1067 // E(S - r_qi) * E(S + a_qi) == E(2*S + a_qi - r_qi)
1068 gcry_mpi_mulm (r_prime[i], r_prime[i], a_pi_prime[i], remote_nsquare);
1070 GNUNET_free (a_pi_prime);
1071 GNUNET_free (rand_pi_prime);
1073 // Calculate S' = E(SUM( r_i^2 ))
1074 s_prime = compute_square_sum (rand, count);
1075 encrypt_element (s_prime, s_prime, remote_g, remote_n, remote_nsquare);
1077 // Calculate S = E(SUM( (r_i + b_i)^2 ))
1078 for (i = 0; i < count; i++)
1080 gcry_mpi_add (rand[i], rand[i], b[i]);
1082 s = compute_square_sum (rand, count);
1083 encrypt_element (s, s, remote_g, remote_n, remote_nsquare);
1084 gcry_mpi_release (remote_n);
1085 gcry_mpi_release (remote_g);
1086 gcry_mpi_release (remote_nsquare);
1088 // release r and tmp
1089 for (i = 0; i < count; i++)
1090 // rp, rq, aq, ap, bp, bq are released along with a, r, b respectively, (a and b are handled at except:)
1091 gcry_mpi_release (rand[i]);
1093 // copy the Kp[], Kq[], S and Stick into a new message
1094 if (GNUNET_YES != prepare_service_response (r, r_prime, s, s_prime, request, response))
1095 GNUNET_log (GNUNET_ERROR_TYPE_INFO, _("Failed to communicate with `%s', scalar product calculation aborted.\n"),
1096 GNUNET_i2s (&request->peer));
1100 for (i = 0; i < count; i++)
1102 gcry_mpi_release (r_prime[i]);
1103 gcry_mpi_release (r[i]);
1106 gcry_mpi_release (s);
1107 gcry_mpi_release (s_prime);
1110 for (i = 0; i < count; i++)
1112 gcry_mpi_release (b[i]);
1113 gcry_mpi_release (request->a[i]);
1117 GNUNET_free (request->a);
1125 * Executed by Alice, fills in a service-request message and sends it to the given peer
1127 * @param session the session associated with this request, then also holds the CORE-handle
1128 * @return #GNUNET_SYSERR if we could not send the message
1129 * #GNUNET_NO if the message was too large
1130 * #GNUNET_OK if we sent it
1133 prepare_service_request (void *cls,
1134 const struct GNUNET_SCHEDULER_TaskContext *tc)
1136 struct ServiceSession * session = cls;
1137 unsigned char * current;
1138 struct GNUNET_SCALARPRODUCT_service_request * msg;
1139 struct MessageObject * msg_obj;
1142 uint16_t msg_length;
1143 size_t element_length = 0; //gets initialized by gcry_mpi_print, but the compiler doesn't know that
1147 session->service_request_task = GNUNET_SCHEDULER_NO_TASK;
1149 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, _ ("Successfully created new tunnel to peer (%s)!\n"), GNUNET_i2s (&session->peer));
1151 msg_length = sizeof (struct GNUNET_SCALARPRODUCT_service_request)
1152 + session->used_element_count * PAILLIER_ELEMENT_LENGTH
1153 + session->mask_length
1154 + my_pubkey_external_length;
1156 if (GNUNET_SERVER_MAX_MESSAGE_SIZE < sizeof (struct GNUNET_SCALARPRODUCT_service_request)
1157 + session->used_element_count * PAILLIER_ELEMENT_LENGTH
1158 + session->mask_length
1159 + my_pubkey_external_length)
1161 // TODO FEATURE: fallback to fragmentation, in case the message is too long
1162 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Message too large, fragmentation is currently not supported!\n"));
1163 GNUNET_CONTAINER_DLL_remove (from_client_head, from_client_tail, session);
1165 session->client_notification_task =
1166 GNUNET_SCHEDULER_add_now (&prepare_client_end_notification,
1170 msg = GNUNET_malloc (msg_length);
1172 msg->header.type = htons (GNUNET_MESSAGE_TYPE_SCALARPRODUCT_ALICE_TO_BOB);
1173 memcpy (&msg->key, &session->key, sizeof (struct GNUNET_HashCode));
1174 msg->mask_length = htons (session->mask_length);
1175 msg->pk_length = htons (my_pubkey_external_length);
1176 msg->used_element_count = htons (session->used_element_count);
1177 msg->element_count = htons (session->element_count);
1178 msg->header.size = htons (msg_length);
1180 // fill in the payload
1181 current = (unsigned char *) &msg[1];
1182 // copy over the mask
1183 memcpy (current, session->mask, session->mask_length);
1184 // copy over our public key
1185 current += session->mask_length;
1186 memcpy (current, my_pubkey_external, my_pubkey_external_length);
1187 current += my_pubkey_external_length;
1189 // now copy over the element vector
1190 session->a = GNUNET_malloc (sizeof (gcry_mpi_t) * session->used_element_count);
1191 a = gcry_mpi_new (KEYBITS * 2);
1192 // encrypt our vector and generate string representations
1193 for (i = 0, j = 0; i < session->element_count; i++)
1195 // if this is a used element...
1196 if (session->mask[i / 8] & 1 << (i % 8))
1198 unsigned char * element_exported = GNUNET_malloc (PAILLIER_ELEMENT_LENGTH);
1199 value = session->vector[i] >= 0 ? session->vector[i] : -session->vector[i];
1201 a = gcry_mpi_set_ui (a, 0);
1202 // long to gcry_mpi_t
1203 if (session->vector[i] < 0)
1204 gcry_mpi_sub_ui (a, a, value);
1206 gcry_mpi_add_ui (a, a, value);
1208 session->a[j++] = gcry_mpi_set (NULL, a);
1209 gcry_mpi_add (a, a, my_offset);
1210 encrypt_element (a, a, my_g, my_n, my_nsquare);
1212 // get representation as string
1213 // we always supply some value, so gcry_mpi_print fails only if it can't reserve memory
1214 GNUNET_assert ( ! gcry_mpi_print (GCRYMPI_FMT_USG,
1215 element_exported, PAILLIER_ELEMENT_LENGTH,
1219 // move buffer content to the end of the buffer so it can easily be read by libgcrypt. also this now has fixed size
1220 adjust (element_exported, element_length, PAILLIER_ELEMENT_LENGTH);
1222 // copy over to the message
1223 memcpy (current, element_exported, PAILLIER_ELEMENT_LENGTH);
1224 current += PAILLIER_ELEMENT_LENGTH;
1227 gcry_mpi_release (a);
1229 msg_obj = GNUNET_new (struct MessageObject);
1230 msg_obj->msg = (struct GNUNET_MessageHeader *) msg;
1231 msg_obj->transmit_handle = (void *) &session->service_transmit_handle; //and reset the transmit handle
1232 GNUNET_log (GNUNET_ERROR_TYPE_INFO, _("Transmitting service request.\n"));
1234 //transmit via mesh messaging
1235 session->state = WAITING_FOR_RESPONSE_FROM_SERVICE;
1236 session->service_transmit_handle = GNUNET_MESH_notify_transmit_ready (session->tunnel, GNUNET_YES,
1237 GNUNET_TIME_UNIT_FOREVER_REL,
1241 if ( ! session->service_transmit_handle)
1243 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, _("Could not send mutlicast message to tunnel!\n"));
1244 GNUNET_free (msg_obj);
1246 GNUNET_CONTAINER_DLL_remove (from_client_head, from_client_tail, session);
1248 session->client_notification_task =
1249 GNUNET_SCHEDULER_add_now (&prepare_client_end_notification,
1255 * Handler for a client request message.
1256 * Can either be type A or B
1257 * A: request-initiation to compute a scalar product with a peer
1258 * B: response role, keep the values + session and wait for a matching session or process a waiting request
1260 * @param cls closure
1261 * @param client identification of the client
1262 * @param message the actual message
1265 handle_client_request (void *cls,
1266 struct GNUNET_SERVER_Client *client,
1267 const struct GNUNET_MessageHeader *message)
1269 const struct GNUNET_SCALARPRODUCT_client_request * msg = (const struct GNUNET_SCALARPRODUCT_client_request *) message;
1270 struct ServiceSession * session;
1271 uint16_t element_count;
1272 uint16_t mask_length;
1277 GNUNET_SERVER_client_get_user_context (client, session);
1278 if (NULL != session){
1279 free_session(session);
1280 // FIXME: also terminate active handles and tasks, in it's not finalized
1281 GNUNET_SERVER_client_set_user_context (client, NULL);
1284 //we need at least a peer and one message id to compare
1285 if (sizeof (struct GNUNET_SCALARPRODUCT_client_request) > ntohs (msg->header.size))
1287 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1288 _ ("Too short message received from client!\n"));
1289 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
1293 msg_type = ntohs (msg->header.type);
1294 element_count = ntohs (msg->element_count);
1295 mask_length = ntohs (msg->mask_length);
1297 //sanity check: is the message as long as the message_count fields suggests?
1298 if (( ntohs (msg->header.size) != (sizeof (struct GNUNET_SCALARPRODUCT_client_request) + element_count * sizeof (int32_t) + mask_length))
1299 || (0 == element_count))
1301 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1302 _ ("Invalid message received from client, session information incorrect!\n"));
1303 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
1307 // do we have a duplicate session here already?
1308 if (NULL != find_matching_session (from_client_tail,
1313 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1314 _ ("Duplicate session information received, cannot create new session with key `%s'\n"),
1315 GNUNET_h2s (&msg->key));
1316 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
1320 session = GNUNET_new (struct ServiceSession);
1321 //FIXME: this actually should not happen here!
1322 GNUNET_SERVER_client_set_user_context (client, session);
1323 session->service_request_task = GNUNET_SCHEDULER_NO_TASK;
1324 session->client_notification_task = GNUNET_SCHEDULER_NO_TASK;
1325 session->client = client;
1326 session->element_count = element_count;
1327 session->mask_length = mask_length;
1328 // get our transaction key
1329 memcpy (&session->key, &msg->key, sizeof (struct GNUNET_HashCode));
1330 //allocate memory for vector and encrypted vector
1331 session->vector = GNUNET_malloc (sizeof (int32_t) * element_count);
1332 vector = (int32_t *) & msg[1];
1334 if (GNUNET_MESSAGE_TYPE_SCALARPRODUCT_CLIENT_TO_ALICE == msg_type)
1336 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1337 _ ("Got client-request-session with key %s, preparing tunnel to remote service.\n"),
1338 GNUNET_h2s (&session->key));
1340 session->role = ALICE;
1342 session->mask = GNUNET_malloc (mask_length);
1343 memcpy (session->mask, &vector[element_count], mask_length);
1345 // copy over the elements
1346 session->used_element_count = 0;
1347 for (i = 0; i < element_count; i++)
1349 session->vector[i] = ntohl (vector[i]);
1350 if (session->vector[i] == 0)
1351 session->mask[i / 8] &= ~(1 << (i % 8));
1352 if (session->mask[i / 8] & (1 << (i % 8)))
1353 session->used_element_count++;
1356 if ( ! session->used_element_count)
1358 GNUNET_break_op (0);
1359 GNUNET_free (session->vector);
1360 GNUNET_free (session->a);
1361 GNUNET_free (session);
1362 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
1365 //session with ourself makes no sense!
1366 if ( ! memcmp (&msg->peer, &me, sizeof (struct GNUNET_PeerIdentity)))
1369 GNUNET_free (session->vector);
1370 GNUNET_free (session->a);
1371 GNUNET_free (session);
1372 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
1376 memcpy (&session->peer, &msg->peer, sizeof (struct GNUNET_PeerIdentity));
1377 GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1378 _ ("Creating new tunnel to for session with key %s.\n"),
1379 GNUNET_h2s (&session->key));
1380 GNUNET_CONTAINER_DLL_insert (from_client_head, from_client_tail, session);
1381 session->tunnel = GNUNET_MESH_tunnel_create (my_mesh, session,
1383 GNUNET_APPLICATION_TYPE_SCALARPRODUCT,
1386 //prepare_service_request, tunnel_peer_disconnect_handler,
1387 if ( ! session->tunnel)
1390 GNUNET_free (session->vector);
1391 GNUNET_free (session->a);
1392 GNUNET_free (session);
1393 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
1396 session->state = WAITING_FOR_BOBS_CONNECT;
1398 session->service_request_task =
1399 GNUNET_SCHEDULER_add_now (&prepare_service_request,
1402 GNUNET_SERVER_receive_done (client, GNUNET_YES);
1406 struct ServiceSession * requesting_session;
1407 enum SessionState needed_state = REQUEST_FROM_SERVICE_RECEIVED;
1409 session->role = BOB;
1410 session->mask = NULL;
1411 // copy over the elements
1412 session->used_element_count = element_count;
1413 for (i = 0; i < element_count; i++)
1414 session->vector[i] = ntohl (vector[i]);
1415 session->state = MESSAGE_FROM_RESPONDING_CLIENT_RECEIVED;
1417 GNUNET_CONTAINER_DLL_insert (from_client_head, from_client_tail, session);
1418 GNUNET_SERVER_receive_done (client, GNUNET_YES);
1419 //check if service queue contains a matching request
1420 requesting_session = find_matching_session (from_service_tail,
1422 session->element_count,
1423 &needed_state, NULL);
1424 if (NULL != requesting_session)
1426 GNUNET_log (GNUNET_ERROR_TYPE_INFO, _ ("Got client-responder-session with key %s and a matching service-request-session set, processing.\n"), GNUNET_h2s (&session->key));
1427 if (GNUNET_OK != compute_service_response (requesting_session, session))
1429 GNUNET_CONTAINER_DLL_remove (from_client_head, from_client_tail, session);
1431 session->client_notification_task =
1432 GNUNET_SCHEDULER_add_now (&prepare_client_end_notification,
1437 GNUNET_log (GNUNET_ERROR_TYPE_INFO, _ ("Got client-responder-session with key %s but NO matching service-request-session set, queuing element for later use.\n"), GNUNET_h2s (&session->key));
1438 // no matching session exists yet, store the response
1439 // for later processing by handle_service_request()
1445 * Function called for inbound tunnels.
1447 * @param cls closure
1448 * @param tunnel new handle to the tunnel
1449 * @param initiator peer that started the tunnel
1450 * @param atsi performance information for the tunnel
1451 * @return initial tunnel context for the tunnel
1452 * (can be NULL -- that's not an error)
1455 tunnel_incoming_handler (void *cls,
1456 struct GNUNET_MESH_Tunnel *tunnel,
1457 const struct GNUNET_PeerIdentity *initiator,
1460 struct ServiceSession * c = GNUNET_new (struct ServiceSession);
1462 c->peer = *initiator;
1470 * Function called whenever a tunnel is destroyed. Should clean up
1471 * any associated state.
1473 * It must NOT call GNUNET_MESH_tunnel_destroy on the tunnel.
1475 * @param cls closure (set from GNUNET_MESH_connect)
1476 * @param tunnel connection to the other end (henceforth invalid)
1477 * @param tunnel_ctx place where local state associated
1478 * with the tunnel is stored
1481 tunnel_destruction_handler (void *cls,
1482 const struct GNUNET_MESH_Tunnel *tunnel,
1485 struct ServiceSession * session = tunnel_ctx;
1486 struct ServiceSession * client_session;
1487 struct ServiceSession * curr;
1489 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1490 _("Peer disconnected, terminating session %s with peer (%s)\n"),
1491 GNUNET_h2s (&session->key),
1492 GNUNET_i2s (&session->peer));
1493 if (ALICE == session->role) {
1494 // as we have only one peer connected in each session, just remove the session
1496 if ((FINALIZED != session->state) && (!do_shutdown))
1498 for (curr = from_client_head; NULL != curr; curr = curr->next)
1499 if (curr == session)
1501 GNUNET_CONTAINER_DLL_remove (from_client_head, from_client_tail, session);
1504 session->tunnel = NULL;
1505 // if this happened before we received the answer, we must terminate the session
1506 session->client_notification_task =
1507 GNUNET_SCHEDULER_add_now (&prepare_client_end_notification,
1511 else { //(BOB == session->role) service session
1513 // remove the session, unless it has already been dequeued, but somehow still active
1514 // this could bug without the IF in case the queue is empty and the service session was the only one know to the service
1515 // scenario: disconnect before alice can send her message to bob.
1516 for (curr = from_service_head; NULL != curr; curr = curr->next)
1517 if (curr == session)
1519 GNUNET_CONTAINER_DLL_remove (from_service_head, from_service_tail, curr);
1522 // there is a client waiting for this service session, terminate it, too!
1523 // i assume the tupel of key and element count is unique. if it was not the rest of the code would not work either.
1524 client_session = find_matching_session (from_client_tail,
1526 session->element_count,
1528 free_session (session);
1530 // the client has to check if it was waiting for a result
1531 // or if it was a responder, no point in adding more statefulness
1532 if (client_session && (!do_shutdown))
1534 client_session->client_notification_task =
1535 GNUNET_SCHEDULER_add_now (&prepare_client_end_notification,
1543 * Compute our scalar product, done by Alice
1545 * @param session - the session associated with this computation
1546 * @param kp - (1) from the protocol definition:
1547 * $E_A(a_{\pi(i)}) \otimes E_A(- r_{\pi(i)} - b_{\pi(i)}) &= E_A(a_{\pi(i)} - r_{\pi(i)} - b_{\pi(i)})$
1548 * @param kq - (2) from the protocol definition:
1549 * $E_A(a_{\pi'(i)}) \otimes E_A(- r_{\pi'(i)}) &= E_A(a_{\pi'(i)} - r_{\pi'(i)})$
1550 * @param s - S from the protocol definition:
1551 * $S := E_A(\sum (r_i + b_i)^2)$
1552 * @param stick - S' from the protocol definition:
1553 * $S' := E_A(\sum r_i^2)$
1554 * @return product as MPI, never NULL
1557 compute_scalar_product (struct ServiceSession * session,
1558 gcry_mpi_t * r, gcry_mpi_t * r_prime, gcry_mpi_t s, gcry_mpi_t s_prime)
1569 count = session->used_element_count;
1570 tmp = gcry_mpi_new (KEYBITS);
1571 // due to the introduced static offset S, we now also have to remove this
1572 // from the E(a_pi)(+)E(-b_pi-r_pi) and E(a_qi)(+)E(-r_qi) twice each,
1573 // the result is E((S + a_pi) + (S -b_pi-r_pi)) and E(S + a_qi + S - r_qi)
1574 for (i = 0; i < count; i++)
1576 decrypt_element (r[i], r[i], my_mu, my_lambda, my_n, my_nsquare);
1577 gcry_mpi_sub(r[i],r[i],my_offset);
1578 gcry_mpi_sub(r[i],r[i],my_offset);
1579 decrypt_element (r_prime[i], r_prime[i], my_mu, my_lambda, my_n, my_nsquare);
1580 gcry_mpi_sub(r_prime[i],r_prime[i],my_offset);
1581 gcry_mpi_sub(r_prime[i],r_prime[i],my_offset);
1584 // calculate t = sum(ai)
1585 t = compute_square_sum (session->a, count);
1588 u = gcry_mpi_new (0);
1589 tmp = compute_square_sum (r, count);
1590 gcry_mpi_sub (u, u, tmp);
1591 gcry_mpi_release (tmp);
1594 utick = gcry_mpi_new (0);
1595 tmp = compute_square_sum (r_prime, count);
1596 gcry_mpi_sub (utick, utick, tmp);
1598 GNUNET_assert (p = gcry_mpi_new (0));
1599 GNUNET_assert (ptick = gcry_mpi_new (0));
1602 decrypt_element (s, s, my_mu, my_lambda, my_n, my_nsquare);
1603 decrypt_element (s_prime, s_prime, my_mu, my_lambda, my_n, my_nsquare);
1606 gcry_mpi_add (p, s, t);
1607 gcry_mpi_add (p, p, u);
1610 gcry_mpi_add (ptick, s_prime, t);
1611 gcry_mpi_add (ptick, ptick, utick);
1613 gcry_mpi_release (t);
1614 gcry_mpi_release (u);
1615 gcry_mpi_release (utick);
1618 gcry_mpi_sub (p, p, ptick);
1619 gcry_mpi_release (ptick);
1620 tmp = gcry_mpi_set_ui (tmp, 2);
1621 gcry_mpi_div (p, NULL, p, tmp, 0);
1623 gcry_mpi_release (tmp);
1624 for (i = 0; i < count; i++)
1625 gcry_mpi_release (session->a[i]);
1626 GNUNET_free (session->a);
1634 * prepare the response we will send to alice or bobs' clients.
1635 * in Bobs case the product will be NULL.
1637 * @param session the session associated with our client.
1640 prepare_client_response (void *cls,
1641 const struct GNUNET_SCHEDULER_TaskContext *tc)
1643 struct ServiceSession * session = cls;
1644 struct GNUNET_SCALARPRODUCT_client_response * msg;
1645 unsigned char * product_exported = NULL;
1646 size_t product_length = 0;
1647 uint16_t msg_length = 0;
1648 struct MessageObject * msg_obj;
1653 session->client_notification_task = GNUNET_SCHEDULER_NO_TASK;
1655 if (session->product)
1657 gcry_mpi_t value = gcry_mpi_new(0);
1659 sign = gcry_mpi_cmp_ui(session->product, 0);
1660 // libgcrypt can not handle a print of a negative number
1662 gcry_mpi_sub(value, value, session->product);
1666 gcry_mpi_add(value, value, session->product);
1671 // get representation as string
1672 // unfortunately libgcrypt is too stupid to implement print-support in
1673 // signed GCRYMPI_FMT_STD format, and simply asserts in that case.
1674 // here is the associated sourcecode:
1675 // if (a->sign) return gcry_error (GPG_ERR_INTERNAL); /* Can't handle it yet. */
1677 && (0 != (rc = gcry_mpi_aprint (GCRYMPI_FMT_USG,
1680 session->product)))){
1681 LOG_GCRY(GNUNET_ERROR_TYPE_ERROR, "gcry_mpi_scan", rc);
1683 range = -1; // signal error with product-length = 0 and range = -1
1686 gcry_mpi_release (session->product);
1687 session->product = NULL;
1690 msg_length = sizeof (struct GNUNET_SCALARPRODUCT_client_response) + product_length;
1691 msg = GNUNET_malloc (msg_length);
1692 memcpy (&msg[1], product_exported, product_length);
1693 GNUNET_free_non_null (product_exported);
1694 msg->header.type = htons (GNUNET_MESSAGE_TYPE_SCALARPRODUCT_SERVICE_TO_CLIENT);
1695 msg->header.size = htons (msg_length);
1697 memcpy (&msg->key, &session->key, sizeof (struct GNUNET_HashCode));
1698 memcpy (&msg->peer, &session->peer, sizeof ( struct GNUNET_PeerIdentity));
1699 msg->product_length = htonl (product_length);
1701 msg_obj = GNUNET_new (struct MessageObject);
1702 msg_obj->msg = (struct GNUNET_MessageHeader *) msg;
1703 msg_obj->transmit_handle = NULL; // don't reset the transmit handle
1705 //transmit this message to our client
1706 session->client_transmit_handle =
1707 GNUNET_SERVER_notify_transmit_ready (session->client,
1709 GNUNET_TIME_UNIT_FOREVER_REL,
1712 if ( ! session->client_transmit_handle)
1714 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1715 _ ("Could not send message to client (%p)! This probably is OK if the client disconnected before us.\n"),
1717 session->client = NULL;
1718 // callback was not called!
1719 GNUNET_free (msg_obj);
1723 // gracefully sent message, just terminate session structure
1724 GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1725 _ ("Sent result to client (%p), this session (%s) has ended!\n"),
1727 GNUNET_h2s (&session->key));
1732 * Handle a request from another service to calculate a scalarproduct with us.
1734 * @param cls closure (set from #GNUNET_MESH_connect)
1735 * @param tunnel connection to the other end
1736 * @param tunnel_ctx place to store local state associated with the tunnel
1737 * @param sender who sent the message
1738 * @param message the actual message
1739 * @param atsi performance data for the connection
1740 * @return #GNUNET_OK to keep the connection open,
1741 * #GNUNET_SYSERR to close it (signal serious error)
1744 handle_service_request (void *cls,
1745 struct GNUNET_MESH_Tunnel * tunnel,
1747 const struct GNUNET_MessageHeader * message)
1749 struct ServiceSession * session;
1750 const struct GNUNET_SCALARPRODUCT_service_request * msg = (const struct GNUNET_SCALARPRODUCT_service_request *) message;
1751 uint16_t mask_length;
1753 uint16_t used_elements;
1754 uint16_t element_count;
1755 uint16_t msg_length;
1756 unsigned char * current;
1757 struct ServiceSession * responder_session;
1759 enum SessionState needed_state;
1761 session = (struct ServiceSession *) * tunnel_ctx;
1762 if (BOB != session->role){
1764 return GNUNET_SYSERR;
1766 // is this tunnel already in use?
1767 if ( (session->next) || (from_service_head == session))
1770 return GNUNET_SYSERR;
1772 // Check if message was sent by me, which would be bad!
1773 if ( ! memcmp (&session->peer, &me, sizeof (struct GNUNET_PeerIdentity)))
1776 GNUNET_free (session);
1777 return GNUNET_SYSERR;
1780 //we need at least a peer and one message id to compare
1781 if (ntohs (msg->header.size) < sizeof (struct GNUNET_SCALARPRODUCT_service_request))
1783 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Too short message received from peer!\n"));
1784 GNUNET_free (session);
1785 return GNUNET_SYSERR;
1787 mask_length = ntohs (msg->mask_length);
1788 pk_length = ntohs (msg->pk_length);
1789 used_elements = ntohs (msg->used_element_count);
1790 element_count = ntohs (msg->element_count);
1791 msg_length = sizeof (struct GNUNET_SCALARPRODUCT_service_request)
1792 + mask_length + pk_length + used_elements * PAILLIER_ELEMENT_LENGTH;
1794 //sanity check: is the message as long as the message_count fields suggests?
1795 if ((ntohs (msg->header.size) != msg_length) || (element_count < used_elements)
1796 || (used_elements == 0) || (mask_length != (element_count / 8 + (element_count % 8 ? 1 : 0)))
1799 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Invalid message received from peer, message count does not match message length!\n"));
1800 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Used elements: %hu\nElement Count: %hu\nExpected Mask Length: %hu\nCalculated Masklength: %d\n"), used_elements, element_count, mask_length, (element_count / 8 + (element_count % 8 ? 1 : 0)));
1801 GNUNET_free (session);
1802 return GNUNET_SYSERR;
1804 if (find_matching_session (from_service_tail,
1810 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, _ ("Got message with duplicate session key (`%s'), ignoring service request.\n"), (const char *) &(msg->key));
1811 GNUNET_free (session);
1812 return GNUNET_SYSERR;
1815 memcpy (&session->peer, &session->peer, sizeof (struct GNUNET_PeerIdentity));
1816 session->state = REQUEST_FROM_SERVICE_RECEIVED;
1817 session->element_count = ntohs (msg->element_count);
1818 session->used_element_count = used_elements;
1819 session->tunnel = tunnel;
1822 memcpy (&session->key, &msg->key, sizeof (struct GNUNET_HashCode));
1823 current = (unsigned char *) &msg[1];
1824 //preserve the mask, we will need that later on
1825 session->mask = GNUNET_malloc (mask_length);
1826 memcpy (session->mask, current, mask_length);
1828 current += mask_length;
1830 //convert the publickey to sexp
1831 if (gcry_sexp_new (&session->remote_pubkey, current, pk_length, 1))
1833 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Could not translate remote public key to sexpression!\n"));
1834 GNUNET_free (session->mask);
1835 GNUNET_free (session);
1836 return GNUNET_SYSERR;
1839 current += pk_length;
1841 //check if service queue contains a matching request
1842 needed_state = MESSAGE_FROM_RESPONDING_CLIENT_RECEIVED;
1843 responder_session = find_matching_session (from_client_tail,
1845 session->element_count,
1846 &needed_state, NULL);
1848 session->a = GNUNET_malloc (sizeof (gcry_mpi_t) * used_elements);
1850 if (GNUNET_SERVER_MAX_MESSAGE_SIZE >= sizeof (struct GNUNET_SCALARPRODUCT_service_request)
1853 + used_elements * PAILLIER_ELEMENT_LENGTH)
1855 gcry_error_t ret = 0;
1856 session->a = GNUNET_malloc (sizeof (gcry_mpi_t) * used_elements);
1857 // Convert each vector element to MPI_value
1858 for (i = 0; i < used_elements; i++)
1862 ret = gcry_mpi_scan (&session->a[i],
1864 ¤t[i * PAILLIER_ELEMENT_LENGTH],
1865 PAILLIER_ELEMENT_LENGTH,
1869 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Could not translate E[a%d] to MPI!\n%s/%s\n"),
1870 i, gcry_strsource (ret), gcry_strerror (ret));
1874 GNUNET_CONTAINER_DLL_insert (from_service_head, from_service_tail, session);
1875 if (responder_session)
1877 GNUNET_log (GNUNET_ERROR_TYPE_INFO, _ ("Got session with key %s and a matching element set, processing.\n"), GNUNET_h2s (&session->key));
1878 if (GNUNET_OK != compute_service_response (session, responder_session))
1880 //something went wrong, remove it again...
1881 GNUNET_CONTAINER_DLL_remove (from_service_head, from_service_tail, session);
1886 GNUNET_log (GNUNET_ERROR_TYPE_INFO, _ ("Got session with key %s without a matching element set, queueing.\n"), GNUNET_h2s (&session->key));
1891 // TODO FEATURE: fallback to fragmentation, in case the message is too long
1892 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Message too large, fragmentation is currently not supported!\n"));
1896 for (i = 0; i < used_elements; i++)
1898 gcry_mpi_release (session->a[i]);
1899 gcry_sexp_release (session->remote_pubkey);
1900 session->remote_pubkey = NULL;
1901 GNUNET_free_non_null (session->a);
1903 free_session (session);
1904 // and notify our client-session that we could not complete the session
1905 if (responder_session)
1907 // we just found the responder session in this queue
1908 GNUNET_CONTAINER_DLL_remove (from_client_head, from_client_tail, responder_session);
1909 responder_session->client_notification_task =
1910 GNUNET_SCHEDULER_add_now (&prepare_client_end_notification,
1913 return GNUNET_SYSERR;
1918 * Handle a response we got from another service we wanted to calculate a scalarproduct with.
1920 * @param cls closure (set from #GNUNET_MESH_connect)
1921 * @param tunnel connection to the other end
1922 * @param tunnel_ctx place to store local state associated with the tunnel
1923 * @param sender who sent the message
1924 * @param message the actual message
1925 * @param atsi performance data for the connection
1926 * @return #GNUNET_OK to keep the connection open,
1927 * #GNUNET_SYSERR to close it (we are done)
1930 handle_service_response (void *cls,
1931 struct GNUNET_MESH_Tunnel * tunnel,
1933 const struct GNUNET_MessageHeader * message)
1935 struct ServiceSession * session;
1936 const struct GNUNET_SCALARPRODUCT_service_response * msg = (const struct GNUNET_SCALARPRODUCT_service_response *) message;
1937 unsigned char * current;
1939 gcry_mpi_t s = NULL;
1940 gcry_mpi_t s_prime = NULL;
1943 uint16_t used_element_count;
1945 gcry_mpi_t * r = NULL;
1946 gcry_mpi_t * r_prime = NULL;
1949 GNUNET_assert (NULL != message);
1950 session = (struct ServiceSession *) * tunnel_ctx;
1951 if (ALICE != session->role){
1953 return GNUNET_SYSERR;
1956 count = session->used_element_count;
1957 session->product = NULL;
1959 //we need at least a peer and one message id to compare
1960 if (sizeof (struct GNUNET_SCALARPRODUCT_service_response) > ntohs (msg->header.size))
1962 GNUNET_break_op (0);
1965 used_element_count = ntohs (msg->used_element_count);
1966 msg_size = sizeof (struct GNUNET_SCALARPRODUCT_service_response)
1967 + 2 * used_element_count * PAILLIER_ELEMENT_LENGTH
1968 + 2 * PAILLIER_ELEMENT_LENGTH;
1969 //sanity check: is the message as long as the message_count fields suggests?
1970 if ((ntohs (msg->header.size) != msg_size) || (count != used_element_count))
1972 GNUNET_break_op (0);
1977 current = (unsigned char *) &msg[1];
1978 if (0 != (rc = gcry_mpi_scan (&s, GCRYMPI_FMT_USG, current,
1979 PAILLIER_ELEMENT_LENGTH, &read)))
1981 LOG_GCRY (GNUNET_ERROR_TYPE_DEBUG, "gcry_mpi_scan", rc);
1982 GNUNET_break_op (0);
1985 current += PAILLIER_ELEMENT_LENGTH;
1987 if (0 != (rc = gcry_mpi_scan (&s_prime, GCRYMPI_FMT_USG, current,
1988 PAILLIER_ELEMENT_LENGTH, &read)))
1990 LOG_GCRY (GNUNET_ERROR_TYPE_DEBUG, "gcry_mpi_scan", rc);
1991 GNUNET_break_op (0);
1994 current += PAILLIER_ELEMENT_LENGTH;
1996 r = GNUNET_malloc (sizeof (gcry_mpi_t) * count);
1997 // Convert each kp[] to its MPI_value
1998 for (i = 0; i < count; i++)
2000 if (0 != (rc = gcry_mpi_scan (&r[i], GCRYMPI_FMT_USG, current,
2001 PAILLIER_ELEMENT_LENGTH, &read)))
2003 LOG_GCRY (GNUNET_ERROR_TYPE_DEBUG, "gcry_mpi_scan", rc);
2004 GNUNET_break_op (0);
2007 current += PAILLIER_ELEMENT_LENGTH;
2011 r_prime = GNUNET_malloc (sizeof (gcry_mpi_t) * count);
2012 // Convert each kq[] to its MPI_value
2013 for (i = 0; i < count; i++)
2015 if (0 != (rc = gcry_mpi_scan (&r_prime[i], GCRYMPI_FMT_USG, current,
2016 PAILLIER_ELEMENT_LENGTH, &read)))
2018 LOG_GCRY (GNUNET_ERROR_TYPE_DEBUG, "gcry_mpi_scan", rc);
2019 GNUNET_break_op (0);
2022 current += PAILLIER_ELEMENT_LENGTH;
2025 session->product = compute_scalar_product (session, r, r_prime, s, s_prime);
2029 gcry_mpi_release (s);
2031 gcry_mpi_release (s_prime);
2032 for (i = 0; r && i < count; i++)
2033 if (r[i]) gcry_mpi_release (r[i]);
2034 for (i = 0; r_prime && i < count; i++)
2035 if (r_prime[i]) gcry_mpi_release (r_prime[i]);
2036 GNUNET_free_non_null (r);
2037 GNUNET_free_non_null (r_prime);
2039 session->state = FINALIZED;
2040 // the tunnel has done its job, terminate our connection and the tunnel
2041 // the peer will be notified that the tunnel was destroyed via tunnel_destruction_handler
2042 GNUNET_CONTAINER_DLL_remove (from_client_head, from_client_tail, session);
2043 // send message with product to client
2045 session->client_notification_task =
2046 GNUNET_SCHEDULER_add_now (&prepare_client_response,
2048 // just close the connection.
2049 return GNUNET_SYSERR;
2053 * Task run during shutdown.
2059 shutdown_task (void *cls,
2060 const struct GNUNET_SCHEDULER_TaskContext *tc)
2062 struct ServiceSession * session;
2063 GNUNET_log (GNUNET_ERROR_TYPE_INFO, _ ("Shutting down, initiating cleanup.\n"));
2065 do_shutdown = GNUNET_YES;
2067 // terminate all owned open tunnels.
2068 for (session = from_client_head; NULL != session; session = session->next)
2070 if (FINALIZED != session->state)
2071 GNUNET_MESH_tunnel_destroy (session->tunnel);
2072 if (GNUNET_SCHEDULER_NO_TASK != session->client_notification_task)
2074 GNUNET_SCHEDULER_cancel (session->client_notification_task);
2075 session->client_notification_task = GNUNET_SCHEDULER_NO_TASK;
2077 if (GNUNET_SCHEDULER_NO_TASK != session->service_request_task)
2079 GNUNET_SCHEDULER_cancel (session->service_request_task);
2080 session->service_request_task = GNUNET_SCHEDULER_NO_TASK;
2083 for (session = from_service_head; NULL != session; session = session->next)
2087 GNUNET_MESH_disconnect (my_mesh);
2094 * Initialization of the program and message handlers
2096 * @param cls closure
2097 * @param server the initialized server
2098 * @param c configuration to use
2102 struct GNUNET_SERVER_Handle *server,
2103 const struct GNUNET_CONFIGURATION_Handle *c)
2105 static const struct GNUNET_SERVER_MessageHandler server_handlers[] = {
2106 {&handle_client_request, NULL, GNUNET_MESSAGE_TYPE_SCALARPRODUCT_CLIENT_TO_ALICE, 0},
2107 {&handle_client_request, NULL, GNUNET_MESSAGE_TYPE_SCALARPRODUCT_CLIENT_TO_BOB, 0},
2110 static const struct GNUNET_MESH_MessageHandler mesh_handlers[] = {
2111 { &handle_service_request, GNUNET_MESSAGE_TYPE_SCALARPRODUCT_ALICE_TO_BOB, 0},
2112 { &handle_service_response, GNUNET_MESSAGE_TYPE_SCALARPRODUCT_BOB_TO_ALICE, 0},
2115 static const uint32_t ports[] = {
2116 GNUNET_APPLICATION_TYPE_SCALARPRODUCT,
2119 //generate private/public key set
2120 GNUNET_log (GNUNET_ERROR_TYPE_INFO, _ ("Generating Paillier-Keyset.\n"));
2122 // register server callbacks and disconnect handler
2123 GNUNET_SERVER_add_handlers (server, server_handlers);
2124 GNUNET_SERVER_disconnect_notify (server,
2125 &handle_client_disconnect,
2127 GNUNET_break (GNUNET_OK ==
2128 GNUNET_CRYPTO_get_host_identity (c,
2130 my_mesh = GNUNET_MESH_connect (c, NULL,
2131 &tunnel_incoming_handler,
2132 &tunnel_destruction_handler,
2133 mesh_handlers, ports);
2136 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, _ ("Connect to MESH failed\n"));
2137 GNUNET_SCHEDULER_shutdown ();
2140 GNUNET_log (GNUNET_ERROR_TYPE_INFO, _ ("Mesh initialized\n"));
2141 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
2148 * The main function for the scalarproduct service.
2150 * @param argc number of arguments from the command line
2151 * @param argv command line arguments
2152 * @return 0 ok, 1 on error
2155 main (int argc, char *const *argv)
2157 return (GNUNET_OK ==
2158 GNUNET_SERVICE_run (argc, argv,
2160 GNUNET_SERVICE_OPTION_NONE,
2161 &run, NULL)) ? 0 : 1;
2164 /* end of gnunet-service-ext.c */