2 This file is part of GNUnet.
3 (C) 2009, 2010, 2011 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 3, or (at your
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11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
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17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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22 * @file nse/gnunet-service-nse.c
23 * @brief network size estimation service
24 * @author Nathan Evans
25 * @author Christian Grothoff
27 * The purpose of this service is to estimate the size of the network.
28 * Given a specified interval, each peer hashes the most recent
29 * timestamp which is evenly divisible by that interval. This hash is
30 * compared in distance to the peer identity to choose an offset. The
31 * closer the peer identity to the hashed timestamp, the earlier the
32 * peer sends out a "nearest peer" message. The closest peer's
33 * message should thus be received before any others, which stops
34 * those peer from sending their messages at a later duration. So
35 * every peer should receive the same nearest peer message, and from
36 * this can calculate the expected number of peers in the network.
40 #include "gnunet_util_lib.h"
41 #include "gnunet_constants.h"
42 #include "gnunet_protocols.h"
43 #include "gnunet_signatures.h"
44 #include "gnunet_statistics_service.h"
45 #include "gnunet_core_service.h"
46 #include "gnunet_nse_service.h"
50 * Should messages be delayed randomly? This option should be set to
51 * GNUNET_NO only for experiments, not in production. It should also
52 * be removed once the initial experiments have been completed.
54 #define USE_RANDOM_DELAYS GNUNET_YES
57 * Should we generate a histogram with the time stamps of when we received
58 * NSE messages to disk? (for performance evaluation only, not useful in
59 * production). The associated code should also probably be removed
60 * once we're done with experiments.
62 #define ENABLE_HISTOGRAM GNUNET_YES
65 * Over how many values do we calculate the weighted average?
67 #define HISTORY_SIZE 64
70 * Message priority to use.
72 #define NSE_PRIORITY 5
75 #define log2(a) (log(a)/log(2))
79 * Amount of work required (W-bit collisions) for NSE proofs, in collision-bits.
81 static unsigned long long nse_work_required;
84 * Interval for sending network size estimation flood requests.
86 static struct GNUNET_TIME_Relative gnunet_nse_interval;
89 * Interval between proof find runs.
91 static struct GNUNET_TIME_Relative proof_find_delay;
95 * Handle for writing when we received messages to disk.
97 static struct GNUNET_BIO_WriteHandle *wh;
102 * Per-peer information.
108 * Core handle for sending messages to this peer.
110 struct GNUNET_CORE_TransmitHandle *th;
113 * What is the identity of the peer?
115 struct GNUNET_PeerIdentity id;
118 * Task scheduled to send message to this peer.
120 GNUNET_SCHEDULER_TaskIdentifier transmit_task;
123 * Did we receive or send a message about the previous round
124 * to this peer yet? GNUNET_YES if the previous round has
125 * been taken care of.
132 * Amount of messages received from this peer on this round.
134 unsigned int received_messages;
137 * Amount of messages transmitted to this peer on this round.
139 unsigned int transmitted_messages;
142 * Which size did we tell the peer the network is?
144 unsigned int last_transmitted_size;
151 GNUNET_NETWORK_STRUCT_BEGIN
154 * Network size estimate reply; sent when "this"
155 * peer's timer has run out before receiving a
156 * valid reply from another peer.
158 struct GNUNET_NSE_FloodMessage
161 * Type: GNUNET_MESSAGE_TYPE_NSE_P2P_FLOOD
163 struct GNUNET_MessageHeader header;
166 * Number of hops this message has taken so far.
168 uint32_t hop_count GNUNET_PACKED;
173 struct GNUNET_CRYPTO_RsaSignaturePurpose purpose;
176 * The current timestamp value (which all
177 * peers should agree on).
179 struct GNUNET_TIME_AbsoluteNBO timestamp;
182 * Number of matching bits between the hash
183 * of timestamp and the initiator's public
186 uint32_t matching_bits GNUNET_PACKED;
189 * Public key of the originator.
191 struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded pkey;
194 * Proof of work, causing leading zeros when hashed with pkey.
196 uint64_t proof_of_work GNUNET_PACKED;
199 * Signature (over range specified in purpose).
201 struct GNUNET_CRYPTO_RsaSignature signature;
203 GNUNET_NETWORK_STRUCT_END
206 * Handle to our current configuration.
208 static const struct GNUNET_CONFIGURATION_Handle *cfg;
211 * Handle to the statistics service.
213 static struct GNUNET_STATISTICS_Handle *stats;
216 * Handle to the core service.
218 static struct GNUNET_CORE_Handle *coreAPI;
221 * Map of all connected peers.
223 static struct GNUNET_CONTAINER_MultiHashMap *peers;
226 * The current network size estimate. Number of bits matching on
229 static double current_size_estimate;
232 * The standard deviation of the last HISTORY_SIZE network
235 static double current_std_dev = NAN;
238 * Current hop counter estimate (estimate for network diameter).
240 static uint32_t hop_count_max;
243 * Message for the next round, if we got any.
245 static struct GNUNET_NSE_FloodMessage next_message;
248 * Array of recent size estimate messages.
250 static struct GNUNET_NSE_FloodMessage size_estimate_messages[HISTORY_SIZE];
253 * Index of most recent estimate.
255 static unsigned int estimate_index;
258 * Number of valid entries in the history.
260 static unsigned int estimate_count;
263 * Task scheduled to update our flood message for the next round.
265 static GNUNET_SCHEDULER_TaskIdentifier flood_task;
268 * Task scheduled to compute our proof.
270 static GNUNET_SCHEDULER_TaskIdentifier proof_task;
273 * Notification context, simplifies client broadcasts.
275 static struct GNUNET_SERVER_NotificationContext *nc;
278 * The next major time.
280 static struct GNUNET_TIME_Absolute next_timestamp;
283 * The current major time.
285 static struct GNUNET_TIME_Absolute current_timestamp;
288 * The public key of this peer.
290 static struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded my_public_key;
293 * The private key of this peer.
295 static struct GNUNET_CRYPTO_RsaPrivateKey *my_private_key;
298 * The peer identity of this peer.
300 static struct GNUNET_PeerIdentity my_identity;
303 * Proof of work for this peer.
305 static uint64_t my_proof;
309 * Initialize a message to clients with the current network
312 * @param em message to fill in
315 setup_estimate_message (struct GNUNET_NSE_ClientMessage *em)
327 /* Weighted incremental algorithm for stddev according to West (1979) */
339 for (i = 0; i < estimate_count; i++)
341 j = (estimate_index - i + HISTORY_SIZE) % HISTORY_SIZE;
342 val = htonl (size_estimate_messages[j].matching_bits);
343 weight = estimate_count + 1 - i;
345 temp = weight + sumweight;
347 r = q * weight / temp;
349 sum += sumweight * q * r;
352 if (estimate_count > 0)
353 variance = (sum / sumweight) * estimate_count / (estimate_count - 1.0);
355 /* trivial version for debugging */
358 /* non-weighted trivial version */
364 for (i = 0; i < estimate_count; i++)
366 j = (estimate_index - i + HISTORY_SIZE) % HISTORY_SIZE;
367 val = htonl (size_estimate_messages[j].matching_bits);
371 if (0 != estimate_count)
373 mean = sum / estimate_count;
374 variance = (vsq - mean * sum) / (estimate_count - 1.0); // terrible for numerical stability...
378 std_dev = sqrt (variance);
380 std_dev = variance; /* must be infinity due to estimate_count == 0 */
381 current_std_dev = std_dev;
382 current_size_estimate = mean;
384 em->header.size = htons (sizeof (struct GNUNET_NSE_ClientMessage));
385 em->header.type = htons (GNUNET_MESSAGE_TYPE_NSE_ESTIMATE);
386 em->reserved = htonl (0);
387 em->timestamp = GNUNET_TIME_absolute_hton (GNUNET_TIME_absolute_get ());
388 double se = mean - 0.332747;
389 nsize = log2 (GNUNET_CONTAINER_multihashmap_size (peers) + 1);
390 em->size_estimate = GNUNET_hton_double (GNUNET_MAX (se, nsize));
391 em->std_deviation = GNUNET_hton_double (std_dev);
392 GNUNET_STATISTICS_set (stats, "# nodes in the network (estimate)",
393 (uint64_t) pow (2, mean - 1.0 / 3.0), GNUNET_NO);
398 * Handler for START message from client, triggers an
399 * immediate current network estimate notification.
400 * Also, we remember the client for updates upon future
401 * estimate measurements.
404 * @param client who sent the message
405 * @param message the message received
408 handle_start_message (void *cls, struct GNUNET_SERVER_Client *client,
409 const struct GNUNET_MessageHeader *message)
411 struct GNUNET_NSE_ClientMessage em;
414 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Received START message from client\n");
416 GNUNET_SERVER_notification_context_add (nc, client);
417 setup_estimate_message (&em);
418 GNUNET_SERVER_notification_context_unicast (nc, client, &em.header,
420 GNUNET_SERVER_receive_done (client, GNUNET_OK);
425 * How long should we delay a message to go the given number of
428 * @param matching_bits number of matching bits to consider
431 get_matching_bits_delay (uint32_t matching_bits)
433 /* Calculated as: S + f/2 - (f / pi) * (atan(x - p')) */
434 // S is next_timestamp (ignored in return value)
435 // f is frequency (gnunet_nse_interval)
436 // x is matching_bits
437 // p' is current_size_estimate
438 return ((double) gnunet_nse_interval.rel_value / (double) 2.0) -
439 ((gnunet_nse_interval.rel_value / M_PI) *
440 atan (matching_bits - current_size_estimate));
445 * What delay randomization should we apply for a given number of matching bits?
447 * @param matching_bits number of matching bits
448 * @return random delay to apply
450 static struct GNUNET_TIME_Relative
451 get_delay_randomization (uint32_t matching_bits)
453 #if USE_RANDOM_DELAYS
454 struct GNUNET_TIME_Relative ret;
458 d = get_matching_bits_delay (matching_bits);
459 i = (uint32_t) (d / (double) (hop_count_max + 1));
461 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
462 "Randomizing flood using latencies up to %u ms\n",
465 ret.rel_value = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, i + 1);
468 return GNUNET_TIME_UNIT_ZERO;
474 * Get the number of matching bits that the given timestamp has to the given peer ID.
476 * @param timestamp time to generate key
477 * @param id peer identity to compare with
478 * @return number of matching bits
481 get_matching_bits (struct GNUNET_TIME_Absolute timestamp,
482 const struct GNUNET_PeerIdentity *id)
484 GNUNET_HashCode timestamp_hash;
486 GNUNET_CRYPTO_hash (×tamp.abs_value, sizeof (timestamp.abs_value),
488 return GNUNET_CRYPTO_hash_matching_bits (×tamp_hash, &id->hashPubKey);
493 * Get the transmission delay that should be applied for a
496 * @param round_offset -1 for the previous round (random delay between 0 and 50ms)
497 * 0 for the current round (based on our proximity to time key)
498 * @return delay that should be applied
500 static struct GNUNET_TIME_Relative
501 get_transmit_delay (int round_offset)
503 struct GNUNET_TIME_Relative ret;
504 struct GNUNET_TIME_Absolute tgt;
506 uint32_t matching_bits;
508 switch (round_offset)
511 /* previous round is randomized between 0 and 50 ms */
512 #if USE_RANDOM_DELAYS
513 ret.rel_value = GNUNET_CRYPTO_random_u64 (GNUNET_CRYPTO_QUALITY_WEAK, 50);
515 ret = GNUNET_TIME_UNIT_ZERO;
518 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
519 "Transmitting previous round behind schedule in %llu ms\n",
520 (unsigned long long) ret.rel_value);
524 /* current round is based on best-known matching_bits */
526 ntohl (size_estimate_messages[estimate_index].matching_bits);
527 dist_delay = get_matching_bits_delay (matching_bits);
528 dist_delay += get_delay_randomization (matching_bits).rel_value;
529 ret.rel_value = (uint64_t) dist_delay;
531 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
532 "For round %llu, delay for %u matching bits is %llu ms\n",
533 (unsigned long long) current_timestamp.abs_value,
534 (unsigned int) matching_bits,
535 (unsigned long long) ret.rel_value);
537 /* now consider round start time and add delay to it */
538 tgt = GNUNET_TIME_absolute_add (current_timestamp, ret);
539 return GNUNET_TIME_absolute_get_remaining (tgt);
542 return GNUNET_TIME_UNIT_FOREVER_REL;
547 * Task that triggers a NSE P2P transmission.
549 * @param cls the 'struct NSEPeerEntry'
550 * @param tc scheduler context
553 transmit_task_cb (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc);
557 * Called when core is ready to send a message we asked for
558 * out to the destination.
560 * @param cls closure (NULL)
561 * @param size number of bytes available in buf
562 * @param buf where the callee should write the message
563 * @return number of bytes written to buf
566 transmit_ready (void *cls, size_t size, void *buf)
568 struct NSEPeerEntry *peer_entry = cls;
571 peer_entry->th = NULL;
574 /* client disconnected */
577 GNUNET_assert (size >= sizeof (struct GNUNET_NSE_FloodMessage));
578 idx = estimate_index;
579 if (GNUNET_NO == peer_entry->previous_round)
581 idx = (idx + HISTORY_SIZE - 1) % HISTORY_SIZE;
582 peer_entry->previous_round = GNUNET_YES;
583 peer_entry->transmit_task =
584 GNUNET_SCHEDULER_add_delayed (get_transmit_delay (0), &transmit_task_cb,
587 if ((ntohl (size_estimate_messages[idx].hop_count) == 0) &&
588 (GNUNET_SCHEDULER_NO_TASK != proof_task))
590 GNUNET_STATISTICS_update (stats,
591 "# flood messages not generated (no proof yet)",
595 if (ntohs (size_estimate_messages[idx].header.size) == 0)
597 GNUNET_STATISTICS_update (stats,
598 "# flood messages not generated (lack of history)",
603 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
604 "In round %llu, sending to `%s' estimate with %u bits\n",
606 GNUNET_TIME_absolute_ntoh (size_estimate_messages[idx].
607 timestamp).abs_value,
608 GNUNET_i2s (&peer_entry->id),
609 (unsigned int) ntohl (size_estimate_messages[idx].matching_bits));
611 if (ntohl (size_estimate_messages[idx].hop_count) == 0)
612 GNUNET_STATISTICS_update (stats, "# flood messages started", 1, GNUNET_NO);
613 GNUNET_STATISTICS_update (stats, "# flood messages transmitted", 1,
616 peer_entry->transmitted_messages++;
617 peer_entry->last_transmitted_size =
618 ntohl(size_estimate_messages[idx].matching_bits);
620 memcpy (buf, &size_estimate_messages[idx],
621 sizeof (struct GNUNET_NSE_FloodMessage));
622 return sizeof (struct GNUNET_NSE_FloodMessage);
627 * Task that triggers a NSE P2P transmission.
629 * @param cls the 'struct NSEPeerEntry'
630 * @param tc scheduler context
633 transmit_task_cb (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
635 struct NSEPeerEntry *peer_entry = cls;
637 peer_entry->transmit_task = GNUNET_SCHEDULER_NO_TASK;
639 GNUNET_assert (NULL == peer_entry->th);
641 GNUNET_CORE_notify_transmit_ready (coreAPI, GNUNET_NO, NSE_PRIORITY,
642 GNUNET_TIME_UNIT_FOREVER_REL,
645 GNUNET_NSE_FloodMessage),
646 &transmit_ready, peer_entry);
651 * We've sent on our flood message or one that we received which was
652 * validated and closer than ours. Update the global list of recent
653 * messages and the average. Also re-broadcast the message to any
657 update_network_size_estimate ()
659 struct GNUNET_NSE_ClientMessage em;
661 setup_estimate_message (&em);
662 GNUNET_SERVER_notification_context_broadcast (nc, &em.header, GNUNET_YES);
667 * Setup a flood message in our history array at the given
668 * slot offset for the given timestamp.
670 * @param slot index to use
671 * @param ts timestamp to use
674 setup_flood_message (unsigned int slot, struct GNUNET_TIME_Absolute ts)
676 struct GNUNET_NSE_FloodMessage *fm;
677 uint32_t matching_bits;
679 matching_bits = get_matching_bits (ts, &my_identity);
680 fm = &size_estimate_messages[slot];
681 fm->header.size = htons (sizeof (struct GNUNET_NSE_FloodMessage));
682 fm->header.type = htons (GNUNET_MESSAGE_TYPE_NSE_P2P_FLOOD);
683 fm->hop_count = htonl (0);
684 fm->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_NSE_SEND);
686 htonl (sizeof (struct GNUNET_NSE_FloodMessage) -
687 sizeof (struct GNUNET_MessageHeader) - sizeof (uint32_t) -
688 sizeof (struct GNUNET_CRYPTO_RsaSignature));
689 fm->matching_bits = htonl (matching_bits);
690 fm->timestamp = GNUNET_TIME_absolute_hton (ts);
691 fm->pkey = my_public_key;
692 fm->proof_of_work = my_proof;
693 if (nse_work_required > 0)
694 GNUNET_assert (GNUNET_OK ==
695 GNUNET_CRYPTO_rsa_sign (my_private_key, &fm->purpose,
698 memset (&fm->signature, 0, sizeof (fm->signature));
703 * Schedule transmission for the given peer for the current round based
704 * on what we know about the desired delay.
707 * @param key hash of peer identity
708 * @param value the 'struct NSEPeerEntry'
709 * @return GNUNET_OK (continue to iterate)
712 schedule_current_round (void *cls, const GNUNET_HashCode * key, void *value)
714 struct NSEPeerEntry *peer_entry = value;
715 struct GNUNET_TIME_Relative delay;
717 if (NULL != peer_entry->th)
719 peer_entry->previous_round = GNUNET_NO;
722 if (GNUNET_SCHEDULER_NO_TASK != peer_entry->transmit_task)
724 GNUNET_SCHEDULER_cancel (peer_entry->transmit_task);
725 peer_entry->previous_round = GNUNET_NO;
728 if (peer_entry->received_messages > 1)
729 GNUNET_STATISTICS_update(stats, "# extra messages",
730 peer_entry->received_messages - 1, GNUNET_NO);
731 peer_entry->transmitted_messages = 0;
732 peer_entry->last_transmitted_size = 0;
733 peer_entry->received_messages = 0;
736 get_transmit_delay ((peer_entry->previous_round == GNUNET_NO) ? -1 : 0);
737 peer_entry->transmit_task =
738 GNUNET_SCHEDULER_add_delayed (delay, &transmit_task_cb, peer_entry);
744 * Update our flood message to be sent (and our timestamps).
747 * @param tc context for this message
750 update_flood_message (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
752 struct GNUNET_TIME_Relative offset;
755 flood_task = GNUNET_SCHEDULER_NO_TASK;
756 if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
758 offset = GNUNET_TIME_absolute_get_remaining (next_timestamp);
759 if (0 != offset.rel_value)
761 /* somehow run early, delay more */
763 GNUNET_SCHEDULER_add_delayed (offset, &update_flood_message, NULL);
766 estimate_index = (estimate_index + 1) % HISTORY_SIZE;
767 if (estimate_count < HISTORY_SIZE)
769 current_timestamp = next_timestamp;
771 GNUNET_TIME_absolute_add (current_timestamp, gnunet_nse_interval);
772 if ((current_timestamp.abs_value ==
773 GNUNET_TIME_absolute_ntoh (next_message.timestamp).abs_value) &&
774 (get_matching_bits (current_timestamp, &my_identity) <
775 ntohl(next_message.matching_bits)))
777 /* we received a message for this round way early, use it! */
778 size_estimate_messages[estimate_index] = next_message;
779 size_estimate_messages[estimate_index].hop_count =
780 htonl (1 + ntohl (next_message.hop_count));
783 setup_flood_message (estimate_index, current_timestamp);
784 next_message.matching_bits = htonl (0); /* reset for 'next' round */
786 for (i = 0; i < HISTORY_SIZE; i++)
788 GNUNET_MAX (ntohl (size_estimate_messages[i].hop_count), hop_count_max);
789 GNUNET_CONTAINER_multihashmap_iterate (peers, &schedule_current_round, NULL);
791 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_absolute_get_remaining
792 (next_timestamp), &update_flood_message,
798 * Count the leading zeroes in hash.
801 * @return the number of leading zero bits.
804 count_leading_zeroes (const GNUNET_HashCode * hash)
806 unsigned int hash_count;
809 while ((0 == GNUNET_CRYPTO_hash_get_bit (hash, hash_count)))
816 * Check whether the given public key
817 * and integer are a valid proof of work.
819 * @param pkey the public key
820 * @param val the integer
822 * @return GNUNET_YES if valid, GNUNET_NO if not
825 check_proof_of_work (const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded *pkey,
828 char buf[sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded) +
830 GNUNET_HashCode result;
832 memcpy (buf, &val, sizeof (val));
833 memcpy (&buf[sizeof (val)], pkey,
834 sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded));
835 GNUNET_CRYPTO_hash (buf, sizeof (buf), &result);
836 return (count_leading_zeroes (&result) >=
837 nse_work_required) ? GNUNET_YES : GNUNET_NO;
842 * Write our current proof to disk.
850 GNUNET_CONFIGURATION_get_value_filename (cfg, "NSE", "PROOFFILE", &proof))
852 if (sizeof (my_proof) !=
853 GNUNET_DISK_fn_write (proof, &my_proof, sizeof (my_proof),
854 GNUNET_DISK_PERM_USER_READ |
855 GNUNET_DISK_PERM_USER_WRITE))
856 GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, "write", proof);
863 * Find our proof of work.
865 * @param cls closure (unused)
866 * @param tc task context
869 find_proof (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
871 #define ROUND_SIZE 10
873 char buf[sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded) +
875 GNUNET_HashCode result;
878 proof_task = GNUNET_SCHEDULER_NO_TASK;
879 memcpy (&buf[sizeof (uint64_t)], &my_public_key,
880 sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded));
883 while ((counter != UINT64_MAX) && (i < ROUND_SIZE))
885 memcpy (buf, &counter, sizeof (uint64_t));
886 GNUNET_CRYPTO_hash (buf, sizeof (buf), &result);
887 if (nse_work_required <= count_leading_zeroes (&result))
891 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Proof of work found: %llu!\n",
892 (unsigned long long) GNUNET_ntohll (counter));
895 setup_flood_message (estimate_index, current_timestamp);
901 if (my_proof / (100 * ROUND_SIZE) < counter / (100 * ROUND_SIZE))
904 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Testing proofs currently at %llu\n",
905 (unsigned long long) counter);
907 /* remember progress every 100 rounds */
916 GNUNET_SCHEDULER_add_delayed_with_priority (proof_find_delay,
917 GNUNET_SCHEDULER_PRIORITY_IDLE,
923 * An incoming flood message has been received which claims
924 * to have more bits matching than any we know in this time
925 * period. Verify the signature and/or proof of work.
927 * @param incoming_flood the message to verify
929 * @return GNUNET_YES if the message is verified
930 * GNUNET_NO if the key/signature don't verify
933 verify_message_crypto (const struct GNUNET_NSE_FloodMessage *incoming_flood)
936 check_proof_of_work (&incoming_flood->pkey,
937 incoming_flood->proof_of_work))
939 GNUNET_log (GNUNET_ERROR_TYPE_INFO, _("Proof of work invalid: %llu!\n"),
941 GNUNET_ntohll (incoming_flood->proof_of_work));
945 if ((nse_work_required > 0) &&
947 GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_NSE_SEND,
948 &incoming_flood->purpose,
949 &incoming_flood->signature,
950 &incoming_flood->pkey)))
960 * Update transmissions for the given peer for the current round based
961 * on updated proximity information.
963 * @param cls peer entry to exclude from updates
964 * @param key hash of peer identity
965 * @param value the 'struct NSEPeerEntry'
966 * @return GNUNET_OK (continue to iterate)
969 update_flood_times (void *cls, const GNUNET_HashCode * key, void *value)
971 struct NSEPeerEntry *exclude = cls;
972 struct NSEPeerEntry *peer_entry = value;
973 struct GNUNET_TIME_Relative delay;
975 if (peer_entry->th != NULL)
976 return GNUNET_OK; /* already active */
977 if (peer_entry == exclude)
978 return GNUNET_OK; /* trigger of the update */
979 if (peer_entry->previous_round == GNUNET_NO)
981 /* still stuck in previous round, no point to update, check that
982 * we are active here though... */
983 if (GNUNET_SCHEDULER_NO_TASK == peer_entry->transmit_task &&
984 NULL == peer_entry->th)
990 if (peer_entry->transmit_task != GNUNET_SCHEDULER_NO_TASK)
992 GNUNET_SCHEDULER_cancel (peer_entry->transmit_task);
993 peer_entry->transmit_task = GNUNET_SCHEDULER_NO_TASK;
995 delay = get_transmit_delay (0);
996 peer_entry->transmit_task =
997 GNUNET_SCHEDULER_add_delayed (delay, &transmit_task_cb, peer_entry);
1003 * Core handler for size estimate flooding messages.
1005 * @param cls closure unused
1006 * @param message message
1007 * @param peer peer identity this message is from (ignored)
1008 * @param atsi performance data (ignored)
1009 * @param atsi_count number of records in 'atsi'
1012 handle_p2p_size_estimate (void *cls, const struct GNUNET_PeerIdentity *peer,
1013 const struct GNUNET_MessageHeader *message,
1014 const struct GNUNET_ATS_Information *atsi,
1015 unsigned int atsi_count)
1017 const struct GNUNET_NSE_FloodMessage *incoming_flood;
1018 struct GNUNET_TIME_Absolute ts;
1019 struct NSEPeerEntry *peer_entry;
1020 uint32_t matching_bits;
1023 #if ENABLE_HISTOGRAM
1025 GNUNET_BIO_write_int64 (wh, GNUNET_TIME_absolute_get ().abs_value);
1027 incoming_flood = (const struct GNUNET_NSE_FloodMessage *) message;
1028 GNUNET_STATISTICS_update (stats, "# flood messages received", 1, GNUNET_NO);
1029 matching_bits = ntohl (incoming_flood->matching_bits);
1034 struct GNUNET_PeerIdentity os;
1036 GNUNET_CRYPTO_hash (&incoming_flood->pkey,
1037 sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
1039 GNUNET_snprintf (origin, sizeof (origin), "%s", GNUNET_i2s (&os));
1040 GNUNET_snprintf (pred, sizeof (pred), "%s", GNUNET_i2s (peer));
1041 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1042 "Flood at %llu from `%s' via `%s' at `%s' with bits %u\n",
1043 (unsigned long long)
1044 GNUNET_TIME_absolute_ntoh (incoming_flood->timestamp).abs_value,
1045 origin, pred, GNUNET_i2s (&my_identity),
1046 (unsigned int) matching_bits);
1050 peer_entry = GNUNET_CONTAINER_multihashmap_get (peers, &peer->hashPubKey);
1051 if (NULL == peer_entry)
1056 #if ENABLE_HISTOGRAM
1057 peer_entry->received_messages++;
1058 if (peer_entry->transmitted_messages > 0 &&
1059 peer_entry->last_transmitted_size >= matching_bits)
1060 GNUNET_STATISTICS_update(stats, "# cross messages", 1, GNUNET_NO);
1063 ts = GNUNET_TIME_absolute_ntoh (incoming_flood->timestamp);
1064 if (ts.abs_value == current_timestamp.abs_value)
1065 idx = estimate_index;
1066 else if (ts.abs_value ==
1067 current_timestamp.abs_value - gnunet_nse_interval.rel_value)
1068 idx = (estimate_index + HISTORY_SIZE - 1) % HISTORY_SIZE;
1069 else if (ts.abs_value == next_timestamp.abs_value)
1071 if (matching_bits <= ntohl (next_message.matching_bits))
1072 return GNUNET_OK; /* ignore, simply too early/late */
1073 if (GNUNET_YES != verify_message_crypto (incoming_flood))
1075 GNUNET_break_op (0);
1078 next_message = *incoming_flood;
1083 GNUNET_STATISTICS_update (stats,
1084 "# flood messages discarded (clock skew too large)",
1088 if (0 == (memcmp (peer, &my_identity, sizeof (struct GNUNET_PeerIdentity))))
1090 /* send to self, update our own estimate IF this also comes from us! */
1092 memcmp (&incoming_flood->pkey, &my_public_key, sizeof (my_public_key)))
1093 update_network_size_estimate ();
1096 if (matching_bits == ntohl (size_estimate_messages[idx].matching_bits))
1098 /* Cancel transmission in the other direction, as this peer clearly has
1099 up-to-date information already. Even if we didn't talk to this peer in
1100 the previous round, we should no longer send it stale information as it
1101 told us about the current round! */
1102 peer_entry->previous_round = GNUNET_YES;
1103 if (idx != estimate_index)
1105 /* do not transmit information for the previous round to this peer
1106 anymore (but allow current round) */
1109 /* got up-to-date information for current round, cancel transmission to
1110 * this peer altogether */
1111 if (GNUNET_SCHEDULER_NO_TASK != peer_entry->transmit_task)
1113 GNUNET_SCHEDULER_cancel (peer_entry->transmit_task);
1114 peer_entry->transmit_task = GNUNET_SCHEDULER_NO_TASK;
1116 if (peer_entry->th != NULL)
1118 GNUNET_CORE_notify_transmit_ready_cancel (peer_entry->th);
1119 peer_entry->th = NULL;
1123 if (matching_bits < ntohl (size_estimate_messages[idx].matching_bits))
1125 if ((idx < estimate_index) && (peer_entry->previous_round == GNUNET_YES)) {
1126 peer_entry->previous_round = GNUNET_NO;
1128 /* push back our result now, that peer is spreading bad information... */
1129 if (NULL == peer_entry->th)
1131 if (peer_entry->transmit_task != GNUNET_SCHEDULER_NO_TASK)
1132 GNUNET_SCHEDULER_cancel (peer_entry->transmit_task);
1133 peer_entry->transmit_task =
1134 GNUNET_SCHEDULER_add_now (&transmit_task_cb, peer_entry);
1136 /* Not closer than our most recent message, no need to do work here */
1137 GNUNET_STATISTICS_update (stats,
1138 "# flood messages ignored (had closer already)",
1142 if (GNUNET_YES != verify_message_crypto (incoming_flood))
1144 GNUNET_break_op (0);
1147 GNUNET_assert (matching_bits >
1148 ntohl (size_estimate_messages[idx].matching_bits));
1149 /* cancel transmission from us to this peer for this round */
1150 if (idx == estimate_index)
1152 /* Cancel transmission in the other direction, as this peer clearly has
1153 up-to-date information already. Even if we didn't talk to this peer in
1154 the previous round, we should no longer send it stale information as it
1155 told us about the current round! */
1156 peer_entry->previous_round = GNUNET_YES;
1157 /* cancel any activity for current round */
1158 if (peer_entry->transmit_task != GNUNET_SCHEDULER_NO_TASK)
1160 GNUNET_SCHEDULER_cancel (peer_entry->transmit_task);
1161 peer_entry->transmit_task = GNUNET_SCHEDULER_NO_TASK;
1163 if (peer_entry->th != NULL)
1165 GNUNET_CORE_notify_transmit_ready_cancel (peer_entry->th);
1166 peer_entry->th = NULL;
1171 /* cancel previous round only */
1172 peer_entry->previous_round = GNUNET_YES;
1174 size_estimate_messages[idx] = *incoming_flood;
1175 size_estimate_messages[idx].hop_count =
1176 htonl (ntohl (incoming_flood->hop_count) + 1);
1178 GNUNET_MAX (ntohl (incoming_flood->hop_count) + 1, hop_count_max);
1179 GNUNET_STATISTICS_set (stats,
1180 "# estimated network diameter",
1181 hop_count_max, GNUNET_NO);
1183 /* have a new, better size estimate, inform clients */
1184 update_network_size_estimate ();
1187 GNUNET_CONTAINER_multihashmap_iterate (peers, &update_flood_times,
1195 * Method called whenever a peer connects. Sets up the PeerEntry and
1196 * schedules the initial size info transmission to this peer.
1198 * @param cls closure
1199 * @param peer peer identity this notification is about
1200 * @param atsi performance data
1201 * @param atsi_count number of records in 'atsi'
1204 handle_core_connect (void *cls, const struct GNUNET_PeerIdentity *peer,
1205 const struct GNUNET_ATS_Information *atsi,
1206 unsigned int atsi_count)
1208 struct NSEPeerEntry *peer_entry;
1211 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Peer `%s' connected to us\n",
1214 peer_entry = GNUNET_malloc (sizeof (struct NSEPeerEntry));
1215 peer_entry->id = *peer;
1216 GNUNET_assert (GNUNET_OK ==
1217 GNUNET_CONTAINER_multihashmap_put (peers, &peer->hashPubKey,
1219 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
1220 peer_entry->transmit_task =
1221 GNUNET_SCHEDULER_add_delayed (get_transmit_delay (-1), &transmit_task_cb,
1223 GNUNET_STATISTICS_update (stats, "# peers", 1, GNUNET_NO);
1228 * Method called whenever a peer disconnects. Deletes the PeerEntry and cancels
1229 * any pending transmission requests to that peer.
1231 * @param cls closure
1232 * @param peer peer identity this notification is about
1235 handle_core_disconnect (void *cls, const struct GNUNET_PeerIdentity *peer)
1237 struct NSEPeerEntry *pos;
1240 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Peer `%s' disconnected from us\n",
1243 pos = GNUNET_CONTAINER_multihashmap_get (peers, &peer->hashPubKey);
1249 GNUNET_assert (GNUNET_YES ==
1250 GNUNET_CONTAINER_multihashmap_remove (peers, &peer->hashPubKey,
1252 if (pos->transmit_task != GNUNET_SCHEDULER_NO_TASK) {
1253 GNUNET_SCHEDULER_cancel (pos->transmit_task);
1254 pos->transmit_task = GNUNET_SCHEDULER_NO_TASK;
1256 if (pos->th != NULL)
1258 GNUNET_CORE_notify_transmit_ready_cancel (pos->th);
1262 GNUNET_STATISTICS_update (stats, "# peers", -1, GNUNET_NO);
1267 * Task run during shutdown.
1273 shutdown_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1275 if (flood_task != GNUNET_SCHEDULER_NO_TASK)
1277 GNUNET_SCHEDULER_cancel (flood_task);
1278 flood_task = GNUNET_SCHEDULER_NO_TASK;
1280 if (proof_task != GNUNET_SCHEDULER_NO_TASK)
1282 GNUNET_SCHEDULER_cancel (proof_task);
1283 proof_task = GNUNET_SCHEDULER_NO_TASK;
1284 write_proof (); /* remember progress */
1288 GNUNET_SERVER_notification_context_destroy (nc);
1291 if (coreAPI != NULL)
1293 GNUNET_CORE_disconnect (coreAPI);
1298 GNUNET_STATISTICS_destroy (stats, GNUNET_NO);
1303 GNUNET_CONTAINER_multihashmap_destroy (peers);
1306 if (my_private_key != NULL)
1308 GNUNET_CRYPTO_rsa_key_free (my_private_key);
1309 my_private_key = NULL;
1311 #if ENABLE_HISTOGRAM
1314 GNUNET_BIO_write_close (wh);
1322 * Called on core init/fail.
1324 * @param cls service closure
1325 * @param server handle to the server for this service
1326 * @param identity the public identity of this peer
1329 core_init (void *cls, struct GNUNET_CORE_Handle *server,
1330 const struct GNUNET_PeerIdentity *identity)
1332 struct GNUNET_TIME_Absolute now;
1333 struct GNUNET_TIME_Absolute prev_time;
1337 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Connection to core FAILED!\n");
1338 GNUNET_SCHEDULER_shutdown ();
1342 memcmp (&my_identity, identity,
1343 sizeof (struct GNUNET_PeerIdentity)));
1344 now = GNUNET_TIME_absolute_get ();
1345 current_timestamp.abs_value =
1346 (now.abs_value / gnunet_nse_interval.rel_value) *
1347 gnunet_nse_interval.rel_value;
1349 GNUNET_TIME_absolute_add (current_timestamp, gnunet_nse_interval);
1350 estimate_index = HISTORY_SIZE - 1;
1352 if (GNUNET_YES == check_proof_of_work (&my_public_key, my_proof))
1354 int idx = (estimate_index + HISTORY_SIZE - 1) % HISTORY_SIZE;
1355 prev_time.abs_value =
1356 current_timestamp.abs_value - gnunet_nse_interval.rel_value;
1357 setup_flood_message (idx, prev_time);
1358 setup_flood_message (estimate_index, current_timestamp);
1362 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_absolute_get_remaining
1363 (next_timestamp), &update_flood_message,
1369 * Handle network size estimate clients.
1371 * @param cls closure
1372 * @param server the initialized server
1373 * @param c configuration to use
1376 run (void *cls, struct GNUNET_SERVER_Handle *server,
1377 const struct GNUNET_CONFIGURATION_Handle *c)
1382 static const struct GNUNET_SERVER_MessageHandler handlers[] = {
1383 {&handle_start_message, NULL, GNUNET_MESSAGE_TYPE_NSE_START,
1384 sizeof (struct GNUNET_MessageHeader)},
1387 static const struct GNUNET_CORE_MessageHandler core_handlers[] = {
1388 {&handle_p2p_size_estimate, GNUNET_MESSAGE_TYPE_NSE_P2P_FLOOD,
1389 sizeof (struct GNUNET_NSE_FloodMessage)},
1395 GNUNET_CONFIGURATION_get_value_time (cfg, "NSE", "INTERVAL",
1396 &gnunet_nse_interval)) ||
1398 GNUNET_CONFIGURATION_get_value_time (cfg, "NSE", "WORKDELAY",
1399 &proof_find_delay)) ||
1401 GNUNET_CONFIGURATION_get_value_number (cfg, "NSE", "WORKBITS",
1402 &nse_work_required)))
1404 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1406 ("NSE service is lacking key configuration settings. Exiting.\n"));
1407 GNUNET_SCHEDULER_shutdown ();
1410 if (nse_work_required >= sizeof (GNUNET_HashCode) * 8)
1412 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1413 _("Invalid work requirement for NSE service. Exiting.\n"));
1414 GNUNET_SCHEDULER_shutdown ();
1420 GNUNET_CONFIGURATION_get_value_filename (cfg, "GNUNETD", "HOSTKEY",
1423 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1425 ("NSE service is lacking key configuration settings. Exiting.\n"));
1426 GNUNET_SCHEDULER_shutdown ();
1429 my_private_key = GNUNET_CRYPTO_rsa_key_create_from_file (keyfile);
1430 GNUNET_free (keyfile);
1431 if (my_private_key == NULL)
1433 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1434 _("NSE service could not access hostkey. Exiting.\n"));
1435 GNUNET_SCHEDULER_shutdown ();
1438 GNUNET_CRYPTO_rsa_key_get_public (my_private_key, &my_public_key);
1439 GNUNET_CRYPTO_hash (&my_public_key, sizeof (my_public_key),
1440 &my_identity.hashPubKey);
1442 GNUNET_CONFIGURATION_get_value_filename (cfg, "NSE", "PROOFFILE", &proof))
1444 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1446 ("NSE service is lacking key configuration settings. Exiting.\n"));
1447 if (my_private_key != NULL)
1449 GNUNET_CRYPTO_rsa_key_free (my_private_key);
1450 my_private_key = NULL;
1452 GNUNET_SCHEDULER_shutdown ();
1455 if ((GNUNET_YES != GNUNET_DISK_file_test (proof)) ||
1456 (sizeof (my_proof) !=
1457 GNUNET_DISK_fn_read (proof, &my_proof, sizeof (my_proof))))
1459 GNUNET_free (proof);
1461 GNUNET_SCHEDULER_add_with_priority (GNUNET_SCHEDULER_PRIORITY_IDLE,
1464 peers = GNUNET_CONTAINER_multihashmap_create (128);
1465 GNUNET_SERVER_add_handlers (server, handlers);
1466 nc = GNUNET_SERVER_notification_context_create (server, 1);
1467 /* Connect to core service and register core handlers */
1468 coreAPI = GNUNET_CORE_connect (cfg, /* Main configuration */
1469 1, NULL, /* Closure passed to functions */
1470 &core_init, /* Call core_init once connected */
1471 &handle_core_connect, /* Handle connects */
1472 &handle_core_disconnect, /* Handle disconnects */
1473 NULL, /* Don't want notified about all incoming messages */
1474 GNUNET_NO, /* For header only inbound notification */
1475 NULL, /* Don't want notified about all outbound messages */
1476 GNUNET_NO, /* For header only outbound notification */
1477 core_handlers); /* Register these handlers */
1478 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL, &shutdown_task,
1480 #if ENABLE_HISTOGRAM
1482 GNUNET_CONFIGURATION_get_value_filename (cfg, "NSE", "HISTOGRAM", &proof))
1484 wh = GNUNET_BIO_write_open (proof);
1485 GNUNET_free (proof);
1488 if (coreAPI == NULL)
1490 GNUNET_SCHEDULER_shutdown ();
1493 stats = GNUNET_STATISTICS_create ("nse", cfg);
1498 * The main function for the statistics service.
1500 * @param argc number of arguments from the command line
1501 * @param argv command line arguments
1502 * @return 0 ok, 1 on error
1505 main (int argc, char *const *argv)
1507 return (GNUNET_OK ==
1508 GNUNET_SERVICE_run (argc, argv, "nse", GNUNET_SERVICE_OPTION_NONE,
1509 &run, NULL)) ? 0 : 1;
1512 /* end of gnunet-service-nse.c */