2 This file is part of GNUnet.
3 (C) 2009, 2010, 2011, 2012, 2013 Christian Grothoff (and other contributing authors)
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6 it under the terms of the GNU General Public License as published
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13 General Public License for more details.
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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"
47 #if ENABLE_NSE_HISTOGRAM
48 #include "gnunet_testbed_logger_service.h"
55 * Should messages be delayed randomly? This option should be set to
56 * GNUNET_NO only for experiments, not in production. It should also
57 * be removed once the initial experiments have been completed.
59 #define USE_RANDOM_DELAYS GNUNET_YES
62 * Generate extensive debug-level log messages?
64 #define DEBUG_NSE GNUNET_NO
67 * Over how many values do we calculate the weighted average?
69 #define HISTORY_SIZE 64
72 * Message priority to use.
74 #define NSE_PRIORITY 5
77 #define log2(a) (log(a)/log(2))
81 * Amount of work required (W-bit collisions) for NSE proofs, in collision-bits.
83 static unsigned long long nse_work_required;
86 * Interval for sending network size estimation flood requests.
88 static struct GNUNET_TIME_Relative gnunet_nse_interval;
91 * Interval between proof find runs.
93 static struct GNUNET_TIME_Relative proof_find_delay;
95 #if ENABLE_NSE_HISTOGRAM
97 * Handle for writing when we received messages to disk.
99 static struct GNUNET_TESTBED_LOGGER_Handle *lh;
104 * Per-peer information.
110 * Core handle for sending messages to this peer.
112 struct GNUNET_CORE_TransmitHandle *th;
115 * What is the identity of the peer?
117 struct GNUNET_PeerIdentity id;
120 * Task scheduled to send message to this peer.
122 GNUNET_SCHEDULER_TaskIdentifier transmit_task;
125 * Did we receive or send a message about the previous round
126 * to this peer yet? GNUNET_YES if the previous round has
127 * been taken care of.
131 #if ENABLE_NSE_HISTOGRAM
134 * Amount of messages received from this peer on this round.
136 unsigned int received_messages;
139 * Amount of messages transmitted to this peer on this round.
141 unsigned int transmitted_messages;
144 * Which size did we tell the peer the network is?
146 unsigned int last_transmitted_size;
153 GNUNET_NETWORK_STRUCT_BEGIN
156 * Network size estimate reply; sent when "this"
157 * peer's timer has run out before receiving a
158 * valid reply from another peer.
160 struct GNUNET_NSE_FloodMessage
163 * Type: GNUNET_MESSAGE_TYPE_NSE_P2P_FLOOD
165 struct GNUNET_MessageHeader header;
168 * Number of hops this message has taken so far.
170 uint32_t hop_count GNUNET_PACKED;
175 struct GNUNET_CRYPTO_EccSignaturePurpose purpose;
178 * The current timestamp value (which all
179 * peers should agree on).
181 struct GNUNET_TIME_AbsoluteNBO timestamp;
184 * Number of matching bits between the hash
185 * of timestamp and the initiator's public
188 uint32_t matching_bits GNUNET_PACKED;
191 * Public key of the originator.
193 struct GNUNET_CRYPTO_EccPublicKey pkey;
196 * Proof of work, causing leading zeros when hashed with pkey.
198 uint64_t proof_of_work GNUNET_PACKED;
201 * Signature (over range specified in purpose).
203 struct GNUNET_CRYPTO_EccSignature signature;
205 GNUNET_NETWORK_STRUCT_END
208 * Handle to our current configuration.
210 static const struct GNUNET_CONFIGURATION_Handle *cfg;
213 * Handle to the statistics service.
215 static struct GNUNET_STATISTICS_Handle *stats;
218 * Handle to the core service.
220 static struct GNUNET_CORE_Handle *coreAPI;
223 * Map of all connected peers.
225 static struct GNUNET_CONTAINER_MultiHashMap *peers;
228 * The current network size estimate. Number of bits matching on
231 static double current_size_estimate;
234 * The standard deviation of the last HISTORY_SIZE network
237 static double current_std_dev = NAN;
240 * Current hop counter estimate (estimate for network diameter).
242 static uint32_t hop_count_max;
245 * Message for the next round, if we got any.
247 static struct GNUNET_NSE_FloodMessage next_message;
250 * Array of recent size estimate messages.
252 static struct GNUNET_NSE_FloodMessage size_estimate_messages[HISTORY_SIZE];
255 * Index of most recent estimate.
257 static unsigned int estimate_index;
260 * Number of valid entries in the history.
262 static unsigned int estimate_count;
265 * Task scheduled to update our flood message for the next round.
267 static GNUNET_SCHEDULER_TaskIdentifier flood_task;
270 * Task scheduled to compute our proof.
272 static GNUNET_SCHEDULER_TaskIdentifier proof_task;
275 * Notification context, simplifies client broadcasts.
277 static struct GNUNET_SERVER_NotificationContext *nc;
280 * The next major time.
282 static struct GNUNET_TIME_Absolute next_timestamp;
285 * The current major time.
287 static struct GNUNET_TIME_Absolute current_timestamp;
290 * The public key of this peer.
292 static struct GNUNET_CRYPTO_EccPublicKey my_public_key;
295 * The private key of this peer.
297 static struct GNUNET_CRYPTO_EccPrivateKey *my_private_key;
300 * The peer identity of this peer.
302 static struct GNUNET_PeerIdentity my_identity;
305 * Proof of work for this peer.
307 static uint64_t my_proof;
310 * Handle to this serivce's server.
312 static struct GNUNET_SERVER_Handle *srv;
316 * Initialize a message to clients with the current network
319 * @param em message to fill in
322 setup_estimate_message (struct GNUNET_NSE_ClientMessage *em)
334 /* Weighted incremental algorithm for stddev according to West (1979) */
346 for (i = 0; i < estimate_count; i++)
348 j = (estimate_index - i + HISTORY_SIZE) % HISTORY_SIZE;
349 val = htonl (size_estimate_messages[j].matching_bits);
350 weight = estimate_count + 1 - i;
352 temp = weight + sumweight;
354 r = q * weight / temp;
356 sum += sumweight * q * r;
359 if (estimate_count > 0)
360 variance = (sum / sumweight) * estimate_count / (estimate_count - 1.0);
362 /* trivial version for debugging */
365 /* non-weighted trivial version */
371 for (i = 0; i < estimate_count; i++)
373 j = (estimate_index - i + HISTORY_SIZE) % HISTORY_SIZE;
374 val = htonl (size_estimate_messages[j].matching_bits);
378 if (0 != estimate_count)
380 mean = sum / estimate_count;
381 variance = (vsq - mean * sum) / (estimate_count - 1.0); // terrible for numerical stability...
385 std_dev = sqrt (variance);
387 std_dev = variance; /* must be infinity due to estimate_count == 0 */
388 current_std_dev = std_dev;
389 current_size_estimate = mean;
391 em->header.size = htons (sizeof (struct GNUNET_NSE_ClientMessage));
392 em->header.type = htons (GNUNET_MESSAGE_TYPE_NSE_ESTIMATE);
393 em->reserved = htonl (0);
394 em->timestamp = GNUNET_TIME_absolute_hton (GNUNET_TIME_absolute_get ());
395 double se = mean - 0.332747;
396 nsize = log2 (GNUNET_CONTAINER_multihashmap_size (peers) + 1);
397 em->size_estimate = GNUNET_hton_double (GNUNET_MAX (se, nsize));
398 em->std_deviation = GNUNET_hton_double (std_dev);
399 GNUNET_STATISTICS_set (stats, "# nodes in the network (estimate)",
400 (uint64_t) pow (2, mean - 1.0 / 3.0), GNUNET_NO);
405 * Handler for START message from client, triggers an
406 * immediate current network estimate notification.
407 * Also, we remember the client for updates upon future
408 * estimate measurements.
411 * @param client who sent the message
412 * @param message the message received
415 handle_start_message (void *cls, struct GNUNET_SERVER_Client *client,
416 const struct GNUNET_MessageHeader *message)
418 struct GNUNET_NSE_ClientMessage em;
420 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Received START message from client\n");
421 GNUNET_SERVER_notification_context_add (nc, client);
422 setup_estimate_message (&em);
423 GNUNET_SERVER_notification_context_unicast (nc, client, &em.header,
425 GNUNET_SERVER_receive_done (client, GNUNET_OK);
430 * How long should we delay a message to go the given number of
433 * @param matching_bits number of matching bits to consider
436 get_matching_bits_delay (uint32_t matching_bits)
438 /* Calculated as: S + f/2 - (f / pi) * (atan(x - p')) */
439 // S is next_timestamp (ignored in return value)
440 // f is frequency (gnunet_nse_interval)
441 // x is matching_bits
442 // p' is current_size_estimate
443 return ((double) gnunet_nse_interval.rel_value_us / (double) 2.0) -
444 ((gnunet_nse_interval.rel_value_us / M_PI) *
445 atan (matching_bits - current_size_estimate));
450 * What delay randomization should we apply for a given number of matching bits?
452 * @param matching_bits number of matching bits
453 * @return random delay to apply
455 static struct GNUNET_TIME_Relative
456 get_delay_randomization (uint32_t matching_bits)
458 #if USE_RANDOM_DELAYS
459 struct GNUNET_TIME_Relative ret;
463 d = get_matching_bits_delay (matching_bits);
464 i = (uint32_t) (d / (double) (hop_count_max + 1));
465 ret.rel_value_us = i;
466 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
467 "Randomizing flood using latencies up to %s\n",
468 GNUNET_STRINGS_relative_time_to_string (ret,
470 ret.rel_value_us = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, i + 1);
473 return GNUNET_TIME_UNIT_ZERO;
479 * Calculate the 'proof-of-work' hash (an expensive hash).
481 * @param buf data to hash
482 * @param buf_len number of bytes in 'buf'
483 * @param result where to write the resulting hash
486 pow_hash (const void *buf,
488 struct GNUNET_HashCode *result)
491 gcry_kdf_derive (buf, buf_len,
494 "gnunet-proof-of-work", strlen ("gnunet-proof-of-work"),
495 2 /* iterations; keep cost of individual op small */,
496 sizeof (struct GNUNET_HashCode), result));
501 * Get the number of matching bits that the given timestamp has to the given peer ID.
503 * @param timestamp time to generate key
504 * @param id peer identity to compare with
505 * @return number of matching bits
508 get_matching_bits (struct GNUNET_TIME_Absolute timestamp,
509 const struct GNUNET_PeerIdentity *id)
511 struct GNUNET_HashCode timestamp_hash;
513 GNUNET_CRYPTO_hash (×tamp.abs_value_us, sizeof (timestamp.abs_value_us),
515 return GNUNET_CRYPTO_hash_matching_bits (×tamp_hash, &id->hashPubKey);
520 * Get the transmission delay that should be applied for a
523 * @param round_offset -1 for the previous round (random delay between 0 and 50ms)
524 * 0 for the current round (based on our proximity to time key)
525 * @return delay that should be applied
527 static struct GNUNET_TIME_Relative
528 get_transmit_delay (int round_offset)
530 struct GNUNET_TIME_Relative ret;
531 struct GNUNET_TIME_Absolute tgt;
533 uint32_t matching_bits;
535 switch (round_offset)
538 /* previous round is randomized between 0 and 50 ms */
539 #if USE_RANDOM_DELAYS
540 ret.rel_value_us = GNUNET_CRYPTO_random_u64 (GNUNET_CRYPTO_QUALITY_WEAK, 50);
542 ret = GNUNET_TIME_UNIT_ZERO;
544 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
545 "Transmitting previous round behind schedule in %s\n",
546 GNUNET_STRINGS_relative_time_to_string (ret, GNUNET_YES));
549 /* current round is based on best-known matching_bits */
551 ntohl (size_estimate_messages[estimate_index].matching_bits);
552 dist_delay = get_matching_bits_delay (matching_bits);
553 dist_delay += get_delay_randomization (matching_bits).rel_value_us;
554 ret.rel_value_us = (uint64_t) dist_delay;
555 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
556 "For round %s, delay for %u matching bits is %s\n",
557 GNUNET_STRINGS_absolute_time_to_string (current_timestamp),
558 (unsigned int) matching_bits,
559 GNUNET_STRINGS_relative_time_to_string (ret,
561 /* now consider round start time and add delay to it */
562 tgt = GNUNET_TIME_absolute_add (current_timestamp, ret);
563 return GNUNET_TIME_absolute_get_remaining (tgt);
566 return GNUNET_TIME_UNIT_FOREVER_REL;
571 * Task that triggers a NSE P2P transmission.
573 * @param cls the 'struct NSEPeerEntry'
574 * @param tc scheduler context
577 transmit_task_cb (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc);
581 * Called when core is ready to send a message we asked for
582 * out to the destination.
584 * @param cls closure (NULL)
585 * @param size number of bytes available in buf
586 * @param buf where the callee should write the message
587 * @return number of bytes written to buf
590 transmit_ready (void *cls, size_t size, void *buf)
592 struct NSEPeerEntry *peer_entry = cls;
595 peer_entry->th = NULL;
598 /* client disconnected */
601 GNUNET_assert (size >= sizeof (struct GNUNET_NSE_FloodMessage));
602 idx = estimate_index;
603 if (GNUNET_NO == peer_entry->previous_round)
605 idx = (idx + HISTORY_SIZE - 1) % HISTORY_SIZE;
606 peer_entry->previous_round = GNUNET_YES;
607 peer_entry->transmit_task =
608 GNUNET_SCHEDULER_add_delayed (get_transmit_delay (0), &transmit_task_cb,
611 if ((0 == ntohl (size_estimate_messages[idx].hop_count)) &&
612 (GNUNET_SCHEDULER_NO_TASK != proof_task))
614 GNUNET_STATISTICS_update (stats,
615 "# flood messages not generated (no proof yet)",
619 if (0 == ntohs (size_estimate_messages[idx].header.size))
621 GNUNET_STATISTICS_update (stats,
622 "# flood messages not generated (lack of history)",
626 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
627 "In round s, sending to `%s' estimate with %u bits\n",
628 GNUNET_STRINGS_absolute_time_to_string (GNUNET_TIME_absolute_ntoh (size_estimate_messages[idx].timestamp)),
629 GNUNET_i2s (&peer_entry->id),
630 (unsigned int) ntohl (size_estimate_messages[idx].matching_bits));
631 if (ntohl (size_estimate_messages[idx].hop_count) == 0)
632 GNUNET_STATISTICS_update (stats, "# flood messages started", 1, GNUNET_NO);
633 GNUNET_STATISTICS_update (stats, "# flood messages transmitted", 1,
635 #if ENABLE_NSE_HISTOGRAM
636 peer_entry->transmitted_messages++;
637 peer_entry->last_transmitted_size =
638 ntohl(size_estimate_messages[idx].matching_bits);
640 memcpy (buf, &size_estimate_messages[idx],
641 sizeof (struct GNUNET_NSE_FloodMessage));
642 return sizeof (struct GNUNET_NSE_FloodMessage);
647 * Task that triggers a NSE P2P transmission.
649 * @param cls the 'struct NSEPeerEntry'
650 * @param tc scheduler context
653 transmit_task_cb (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
655 struct NSEPeerEntry *peer_entry = cls;
657 peer_entry->transmit_task = GNUNET_SCHEDULER_NO_TASK;
659 GNUNET_assert (NULL == peer_entry->th);
661 GNUNET_CORE_notify_transmit_ready (coreAPI, GNUNET_NO, NSE_PRIORITY,
662 GNUNET_TIME_UNIT_FOREVER_REL,
665 GNUNET_NSE_FloodMessage),
666 &transmit_ready, peer_entry);
671 * We've sent on our flood message or one that we received which was
672 * validated and closer than ours. Update the global list of recent
673 * messages and the average. Also re-broadcast the message to any
677 update_network_size_estimate ()
679 struct GNUNET_NSE_ClientMessage em;
681 setup_estimate_message (&em);
682 GNUNET_SERVER_notification_context_broadcast (nc, &em.header, GNUNET_YES);
687 * Setup a flood message in our history array at the given
688 * slot offset for the given timestamp.
690 * @param slot index to use
691 * @param ts timestamp to use
694 setup_flood_message (unsigned int slot,
695 struct GNUNET_TIME_Absolute ts)
697 struct GNUNET_NSE_FloodMessage *fm;
698 uint32_t matching_bits;
700 matching_bits = get_matching_bits (ts, &my_identity);
701 fm = &size_estimate_messages[slot];
702 fm->header.size = htons (sizeof (struct GNUNET_NSE_FloodMessage));
703 fm->header.type = htons (GNUNET_MESSAGE_TYPE_NSE_P2P_FLOOD);
704 fm->hop_count = htonl (0);
705 fm->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_NSE_SEND);
707 htonl (sizeof (struct GNUNET_NSE_FloodMessage) -
708 sizeof (struct GNUNET_MessageHeader) - sizeof (uint32_t) -
709 sizeof (struct GNUNET_CRYPTO_EccSignature));
710 fm->matching_bits = htonl (matching_bits);
711 fm->timestamp = GNUNET_TIME_absolute_hton (ts);
712 fm->pkey = my_public_key;
713 fm->proof_of_work = my_proof;
714 if (nse_work_required > 0)
715 GNUNET_assert (GNUNET_OK ==
716 GNUNET_CRYPTO_ecc_sign (my_private_key, &fm->purpose,
719 memset (&fm->signature, 0, sizeof (fm->signature));
724 * Schedule transmission for the given peer for the current round based
725 * on what we know about the desired delay.
728 * @param key hash of peer identity
729 * @param value the 'struct NSEPeerEntry'
730 * @return GNUNET_OK (continue to iterate)
733 schedule_current_round (void *cls,
734 const struct GNUNET_HashCode * key,
737 struct NSEPeerEntry *peer_entry = value;
738 struct GNUNET_TIME_Relative delay;
740 if (NULL != peer_entry->th)
742 peer_entry->previous_round = GNUNET_NO;
745 if (GNUNET_SCHEDULER_NO_TASK != peer_entry->transmit_task)
747 GNUNET_SCHEDULER_cancel (peer_entry->transmit_task);
748 peer_entry->previous_round = GNUNET_NO;
750 #if ENABLE_NSE_HISTOGRAM
751 if (peer_entry->received_messages > 1)
752 GNUNET_STATISTICS_update(stats, "# extra messages",
753 peer_entry->received_messages - 1, GNUNET_NO);
754 peer_entry->transmitted_messages = 0;
755 peer_entry->last_transmitted_size = 0;
756 peer_entry->received_messages = 0;
759 get_transmit_delay ((peer_entry->previous_round == GNUNET_NO) ? -1 : 0);
760 peer_entry->transmit_task =
761 GNUNET_SCHEDULER_add_delayed (delay, &transmit_task_cb, peer_entry);
767 * Update our flood message to be sent (and our timestamps).
770 * @param tc context for this message
773 update_flood_message (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
775 struct GNUNET_TIME_Relative offset;
778 flood_task = GNUNET_SCHEDULER_NO_TASK;
779 if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
781 offset = GNUNET_TIME_absolute_get_remaining (next_timestamp);
782 if (0 != offset.rel_value_us)
784 /* somehow run early, delay more */
786 GNUNET_SCHEDULER_add_delayed (offset, &update_flood_message, NULL);
789 estimate_index = (estimate_index + 1) % HISTORY_SIZE;
790 if (estimate_count < HISTORY_SIZE)
792 current_timestamp = next_timestamp;
794 GNUNET_TIME_absolute_add (current_timestamp, gnunet_nse_interval);
795 if ((current_timestamp.abs_value_us ==
796 GNUNET_TIME_absolute_ntoh (next_message.timestamp).abs_value_us) &&
797 (get_matching_bits (current_timestamp, &my_identity) <
798 ntohl(next_message.matching_bits)))
800 /* we received a message for this round way early, use it! */
801 size_estimate_messages[estimate_index] = next_message;
802 size_estimate_messages[estimate_index].hop_count =
803 htonl (1 + ntohl (next_message.hop_count));
806 setup_flood_message (estimate_index, current_timestamp);
807 next_message.matching_bits = htonl (0); /* reset for 'next' round */
809 for (i = 0; i < HISTORY_SIZE; i++)
811 GNUNET_MAX (ntohl (size_estimate_messages[i].hop_count), hop_count_max);
812 GNUNET_CONTAINER_multihashmap_iterate (peers, &schedule_current_round, NULL);
814 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_absolute_get_remaining
815 (next_timestamp), &update_flood_message,
821 * Count the leading zeroes in hash.
824 * @return the number of leading zero bits.
827 count_leading_zeroes (const struct GNUNET_HashCode * hash)
829 unsigned int hash_count;
832 while ((0 == GNUNET_CRYPTO_hash_get_bit (hash, hash_count)))
839 * Check whether the given public key
840 * and integer are a valid proof of work.
842 * @param pkey the public key
843 * @param val the integer
845 * @return GNUNET_YES if valid, GNUNET_NO if not
848 check_proof_of_work (const struct GNUNET_CRYPTO_EccPublicKey *pkey,
851 char buf[sizeof (struct GNUNET_CRYPTO_EccPublicKey) +
852 sizeof (val)] GNUNET_ALIGN;
853 struct GNUNET_HashCode result;
855 memcpy (buf, &val, sizeof (val));
856 memcpy (&buf[sizeof (val)], pkey,
857 sizeof (struct GNUNET_CRYPTO_EccPublicKey));
858 pow_hash (buf, sizeof (buf), &result);
859 return (count_leading_zeroes (&result) >=
860 nse_work_required) ? GNUNET_YES : GNUNET_NO;
865 * Write our current proof to disk.
873 GNUNET_CONFIGURATION_get_value_filename (cfg, "NSE", "PROOFFILE", &proof))
875 if (sizeof (my_proof) !=
876 GNUNET_DISK_fn_write (proof, &my_proof, sizeof (my_proof),
877 GNUNET_DISK_PERM_USER_READ |
878 GNUNET_DISK_PERM_USER_WRITE))
879 GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, "write", proof);
886 * Find our proof of work.
888 * @param cls closure (unused)
889 * @param tc task context
892 find_proof (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
894 #define ROUND_SIZE 10
896 char buf[sizeof (struct GNUNET_CRYPTO_EccPublicKey) +
897 sizeof (uint64_t)] GNUNET_ALIGN;
898 struct GNUNET_HashCode result;
901 proof_task = GNUNET_SCHEDULER_NO_TASK;
902 memcpy (&buf[sizeof (uint64_t)], &my_public_key,
903 sizeof (struct GNUNET_CRYPTO_EccPublicKey));
906 while ((counter != UINT64_MAX) && (i < ROUND_SIZE))
908 memcpy (buf, &counter, sizeof (uint64_t));
909 pow_hash (buf, sizeof (buf), &result);
910 if (nse_work_required <= count_leading_zeroes (&result))
913 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Proof of work found: %llu!\n",
914 (unsigned long long) GNUNET_ntohll (counter));
916 setup_flood_message (estimate_index, current_timestamp);
922 if (my_proof / (100 * ROUND_SIZE) < counter / (100 * ROUND_SIZE))
924 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Testing proofs currently at %llu\n",
925 (unsigned long long) counter);
926 /* remember progress every 100 rounds */
935 GNUNET_SCHEDULER_add_delayed_with_priority (proof_find_delay,
936 GNUNET_SCHEDULER_PRIORITY_IDLE,
942 * An incoming flood message has been received which claims
943 * to have more bits matching than any we know in this time
944 * period. Verify the signature and/or proof of work.
946 * @param incoming_flood the message to verify
948 * @return GNUNET_YES if the message is verified
949 * GNUNET_NO if the key/signature don't verify
952 verify_message_crypto (const struct GNUNET_NSE_FloodMessage *incoming_flood)
955 check_proof_of_work (&incoming_flood->pkey,
956 incoming_flood->proof_of_work))
958 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Proof of work invalid: %llu!\n",
960 GNUNET_ntohll (incoming_flood->proof_of_work));
964 if ((nse_work_required > 0) &&
966 GNUNET_CRYPTO_ecc_verify (GNUNET_SIGNATURE_PURPOSE_NSE_SEND,
967 &incoming_flood->purpose,
968 &incoming_flood->signature,
969 &incoming_flood->pkey)))
979 * Update transmissions for the given peer for the current round based
980 * on updated proximity information.
982 * @param cls peer entry to exclude from updates
983 * @param key hash of peer identity
984 * @param value the 'struct NSEPeerEntry'
985 * @return GNUNET_OK (continue to iterate)
988 update_flood_times (void *cls, const struct GNUNET_HashCode * key, void *value)
990 struct NSEPeerEntry *exclude = cls;
991 struct NSEPeerEntry *peer_entry = value;
992 struct GNUNET_TIME_Relative delay;
994 if (NULL != peer_entry->th)
995 return GNUNET_OK; /* already active */
996 if (peer_entry == exclude)
997 return GNUNET_OK; /* trigger of the update */
998 if (peer_entry->previous_round == GNUNET_NO)
1000 /* still stuck in previous round, no point to update, check that
1001 * we are active here though... */
1002 if ( (GNUNET_SCHEDULER_NO_TASK == peer_entry->transmit_task) &&
1003 (NULL == peer_entry->th) )
1009 if (GNUNET_SCHEDULER_NO_TASK != peer_entry->transmit_task)
1011 GNUNET_SCHEDULER_cancel (peer_entry->transmit_task);
1012 peer_entry->transmit_task = GNUNET_SCHEDULER_NO_TASK;
1014 delay = get_transmit_delay (0);
1015 peer_entry->transmit_task =
1016 GNUNET_SCHEDULER_add_delayed (delay, &transmit_task_cb, peer_entry);
1022 * Core handler for size estimate flooding messages.
1024 * @param cls closure unused
1025 * @param message message
1026 * @param peer peer identity this message is from (ignored)
1029 handle_p2p_size_estimate (void *cls, const struct GNUNET_PeerIdentity *peer,
1030 const struct GNUNET_MessageHeader *message)
1032 const struct GNUNET_NSE_FloodMessage *incoming_flood;
1033 struct GNUNET_TIME_Absolute ts;
1034 struct NSEPeerEntry *peer_entry;
1035 uint32_t matching_bits;
1038 #if ENABLE_NSE_HISTOGRAM
1042 t = GNUNET_TIME_absolute_get().abs_value_us;
1043 GNUNET_TESTBED_LOGGER_write (lh, &t, sizeof (uint64_t));
1046 incoming_flood = (const struct GNUNET_NSE_FloodMessage *) message;
1047 GNUNET_STATISTICS_update (stats, "# flood messages received", 1, GNUNET_NO);
1048 matching_bits = ntohl (incoming_flood->matching_bits);
1053 struct GNUNET_PeerIdentity os;
1055 GNUNET_CRYPTO_hash (&incoming_flood->pkey,
1056 sizeof (struct GNUNET_CRYPTO_EccPublicKey),
1058 GNUNET_snprintf (origin, sizeof (origin), "%s", GNUNET_i2s (&os));
1059 GNUNET_snprintf (pred, sizeof (pred), "%s", GNUNET_i2s (peer));
1060 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1061 "Flood at %s from `%s' via `%s' at `%s' with bits %u\n",
1062 GNUNET_STRINGS_absolute_time_to_string (GNUNET_TIME_absolute_ntoh (incoming_flood->timestamp)),
1063 origin, pred, GNUNET_i2s (&my_identity),
1064 (unsigned int) matching_bits);
1068 peer_entry = GNUNET_CONTAINER_multihashmap_get (peers, &peer->hashPubKey);
1069 if (NULL == peer_entry)
1074 #if ENABLE_NSE_HISTOGRAM
1075 peer_entry->received_messages++;
1076 if (peer_entry->transmitted_messages > 0 &&
1077 peer_entry->last_transmitted_size >= matching_bits)
1078 GNUNET_STATISTICS_update(stats, "# cross messages", 1, GNUNET_NO);
1081 ts = GNUNET_TIME_absolute_ntoh (incoming_flood->timestamp);
1082 if (ts.abs_value_us == current_timestamp.abs_value_us)
1083 idx = estimate_index;
1084 else if (ts.abs_value_us ==
1085 current_timestamp.abs_value_us - gnunet_nse_interval.rel_value_us)
1086 idx = (estimate_index + HISTORY_SIZE - 1) % HISTORY_SIZE;
1087 else if (ts.abs_value_us == next_timestamp.abs_value_us)
1089 if (matching_bits <= ntohl (next_message.matching_bits))
1090 return GNUNET_OK; /* ignore, simply too early/late */
1091 if (GNUNET_YES != verify_message_crypto (incoming_flood))
1093 GNUNET_break_op (0);
1096 next_message = *incoming_flood;
1101 GNUNET_STATISTICS_update (stats,
1102 "# flood messages discarded (clock skew too large)",
1106 if (0 == (memcmp (peer, &my_identity, sizeof (struct GNUNET_PeerIdentity))))
1108 /* send to self, update our own estimate IF this also comes from us! */
1110 memcmp (&incoming_flood->pkey, &my_public_key, sizeof (my_public_key)))
1111 update_network_size_estimate ();
1114 if (matching_bits == ntohl (size_estimate_messages[idx].matching_bits))
1116 /* Cancel transmission in the other direction, as this peer clearly has
1117 up-to-date information already. Even if we didn't talk to this peer in
1118 the previous round, we should no longer send it stale information as it
1119 told us about the current round! */
1120 peer_entry->previous_round = GNUNET_YES;
1121 if (idx != estimate_index)
1123 /* do not transmit information for the previous round to this peer
1124 anymore (but allow current round) */
1127 /* got up-to-date information for current round, cancel transmission to
1128 * this peer altogether */
1129 if (GNUNET_SCHEDULER_NO_TASK != peer_entry->transmit_task)
1131 GNUNET_SCHEDULER_cancel (peer_entry->transmit_task);
1132 peer_entry->transmit_task = GNUNET_SCHEDULER_NO_TASK;
1134 if (NULL != peer_entry->th)
1136 GNUNET_CORE_notify_transmit_ready_cancel (peer_entry->th);
1137 peer_entry->th = NULL;
1141 if (matching_bits < ntohl (size_estimate_messages[idx].matching_bits))
1143 if ((idx < estimate_index) && (peer_entry->previous_round == GNUNET_YES)) {
1144 peer_entry->previous_round = GNUNET_NO;
1146 /* push back our result now, that peer is spreading bad information... */
1147 if (NULL == peer_entry->th)
1149 if (peer_entry->transmit_task != GNUNET_SCHEDULER_NO_TASK)
1150 GNUNET_SCHEDULER_cancel (peer_entry->transmit_task);
1151 peer_entry->transmit_task =
1152 GNUNET_SCHEDULER_add_now (&transmit_task_cb, peer_entry);
1154 /* Not closer than our most recent message, no need to do work here */
1155 GNUNET_STATISTICS_update (stats,
1156 "# flood messages ignored (had closer already)",
1160 if (GNUNET_YES != verify_message_crypto (incoming_flood))
1162 GNUNET_break_op (0);
1165 GNUNET_assert (matching_bits >
1166 ntohl (size_estimate_messages[idx].matching_bits));
1167 /* Cancel transmission in the other direction, as this peer clearly has
1168 * up-to-date information already.
1170 peer_entry->previous_round = GNUNET_YES;
1171 if (idx == estimate_index)
1173 /* cancel any activity for current round */
1174 if (peer_entry->transmit_task != GNUNET_SCHEDULER_NO_TASK)
1176 GNUNET_SCHEDULER_cancel (peer_entry->transmit_task);
1177 peer_entry->transmit_task = GNUNET_SCHEDULER_NO_TASK;
1179 if (peer_entry->th != NULL)
1181 GNUNET_CORE_notify_transmit_ready_cancel (peer_entry->th);
1182 peer_entry->th = NULL;
1185 size_estimate_messages[idx] = *incoming_flood;
1186 size_estimate_messages[idx].hop_count =
1187 htonl (ntohl (incoming_flood->hop_count) + 1);
1189 GNUNET_MAX (ntohl (incoming_flood->hop_count) + 1, hop_count_max);
1190 GNUNET_STATISTICS_set (stats,
1191 "# estimated network diameter",
1192 hop_count_max, GNUNET_NO);
1194 /* have a new, better size estimate, inform clients */
1195 update_network_size_estimate ();
1198 GNUNET_CONTAINER_multihashmap_iterate (peers, &update_flood_times,
1206 * Method called whenever a peer connects. Sets up the PeerEntry and
1207 * schedules the initial size info transmission to this peer.
1209 * @param cls closure
1210 * @param peer peer identity this notification is about
1213 handle_core_connect (void *cls, const struct GNUNET_PeerIdentity *peer)
1215 struct NSEPeerEntry *peer_entry;
1217 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Peer `%s' connected to us\n",
1219 peer_entry = GNUNET_malloc (sizeof (struct NSEPeerEntry));
1220 peer_entry->id = *peer;
1221 GNUNET_assert (GNUNET_OK ==
1222 GNUNET_CONTAINER_multihashmap_put (peers, &peer->hashPubKey,
1224 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
1225 peer_entry->transmit_task =
1226 GNUNET_SCHEDULER_add_delayed (get_transmit_delay (-1), &transmit_task_cb,
1228 GNUNET_STATISTICS_update (stats, "# peers connected", 1, GNUNET_NO);
1233 * Method called whenever a peer disconnects. Deletes the PeerEntry and cancels
1234 * any pending transmission requests to that peer.
1236 * @param cls closure
1237 * @param peer peer identity this notification is about
1240 handle_core_disconnect (void *cls, const struct GNUNET_PeerIdentity *peer)
1242 struct NSEPeerEntry *pos;
1244 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Peer `%s' disconnected from us\n",
1246 pos = GNUNET_CONTAINER_multihashmap_get (peers, &peer->hashPubKey);
1252 GNUNET_assert (GNUNET_YES ==
1253 GNUNET_CONTAINER_multihashmap_remove (peers, &peer->hashPubKey,
1255 if (pos->transmit_task != GNUNET_SCHEDULER_NO_TASK) {
1256 GNUNET_SCHEDULER_cancel (pos->transmit_task);
1257 pos->transmit_task = GNUNET_SCHEDULER_NO_TASK;
1259 if (NULL != pos->th)
1261 GNUNET_CORE_notify_transmit_ready_cancel (pos->th);
1265 GNUNET_STATISTICS_update (stats, "# peers connected", -1, GNUNET_NO);
1269 #if ENABLE_NSE_HISTOGRAM
1271 * Functions of this type are called to notify a successful transmission of the
1272 * message to the logger service
1275 * @param size the amount of data sent
1278 flush_comp_cb (void *cls, size_t size)
1280 GNUNET_TESTBED_LOGGER_disconnect (lh);
1287 * Task run during shutdown.
1293 shutdown_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
1295 if (GNUNET_SCHEDULER_NO_TASK != flood_task)
1297 GNUNET_SCHEDULER_cancel (flood_task);
1298 flood_task = GNUNET_SCHEDULER_NO_TASK;
1300 if (GNUNET_SCHEDULER_NO_TASK != proof_task)
1302 GNUNET_SCHEDULER_cancel (proof_task);
1303 proof_task = GNUNET_SCHEDULER_NO_TASK;
1304 write_proof (); /* remember progress */
1308 GNUNET_SERVER_notification_context_destroy (nc);
1311 if (NULL != coreAPI)
1313 GNUNET_CORE_disconnect (coreAPI);
1318 GNUNET_STATISTICS_destroy (stats, GNUNET_NO);
1323 GNUNET_CONTAINER_multihashmap_destroy (peers);
1326 if (NULL != my_private_key)
1328 GNUNET_free (my_private_key);
1329 my_private_key = NULL;
1331 #if ENABLE_NSE_HISTOGRAM
1332 struct GNUNET_TIME_Relative timeout;
1333 timeout = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 30);
1334 GNUNET_TESTBED_LOGGER_flush (lh, timeout, &flush_comp_cb, NULL);
1340 * Called on core init/fail.
1342 * @param cls service closure
1343 * @param identity the public identity of this peer
1346 core_init (void *cls,
1347 const struct GNUNET_PeerIdentity *identity)
1349 struct GNUNET_TIME_Absolute now;
1350 struct GNUNET_TIME_Absolute prev_time;
1352 if (NULL == identity)
1354 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Connection to core FAILED!\n");
1355 GNUNET_SCHEDULER_shutdown ();
1359 memcmp (&my_identity, identity,
1360 sizeof (struct GNUNET_PeerIdentity)));
1361 now = GNUNET_TIME_absolute_get ();
1362 current_timestamp.abs_value_us =
1363 (now.abs_value_us / gnunet_nse_interval.rel_value_us) *
1364 gnunet_nse_interval.rel_value_us;
1366 GNUNET_TIME_absolute_add (current_timestamp, gnunet_nse_interval);
1367 estimate_index = HISTORY_SIZE - 1;
1369 if (GNUNET_YES == check_proof_of_work (&my_public_key, my_proof))
1371 int idx = (estimate_index + HISTORY_SIZE - 1) % HISTORY_SIZE;
1372 prev_time.abs_value_us =
1373 current_timestamp.abs_value_us - gnunet_nse_interval.rel_value_us;
1374 setup_flood_message (idx, prev_time);
1375 setup_flood_message (estimate_index, current_timestamp);
1379 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_absolute_get_remaining
1380 (next_timestamp), &update_flood_message,
1386 * Handle network size estimate clients.
1388 * @param cls closure
1389 * @param server the initialized server
1390 * @param c configuration to use
1394 struct GNUNET_SERVER_Handle *server,
1395 const struct GNUNET_CONFIGURATION_Handle *c)
1397 static const struct GNUNET_SERVER_MessageHandler handlers[] = {
1398 {&handle_start_message, NULL, GNUNET_MESSAGE_TYPE_NSE_START,
1399 sizeof (struct GNUNET_MessageHeader)},
1402 static const struct GNUNET_CORE_MessageHandler core_handlers[] = {
1403 {&handle_p2p_size_estimate, GNUNET_MESSAGE_TYPE_NSE_P2P_FLOOD,
1404 sizeof (struct GNUNET_NSE_FloodMessage)},
1409 struct GNUNET_CRYPTO_EccPrivateKey *pk;
1414 GNUNET_CONFIGURATION_get_value_time (cfg, "NSE", "INTERVAL",
1415 &gnunet_nse_interval)) ||
1417 GNUNET_CONFIGURATION_get_value_time (cfg, "NSE", "WORKDELAY",
1418 &proof_find_delay)) ||
1420 GNUNET_CONFIGURATION_get_value_number (cfg, "NSE", "WORKBITS",
1421 &nse_work_required)))
1423 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1425 ("%s service is lacking key configuration settings (%s). Exiting.\n"),
1426 "NSE", "interval/workdelay/workbits");
1427 GNUNET_SCHEDULER_shutdown ();
1430 if (nse_work_required >= sizeof (struct GNUNET_HashCode) * 8)
1432 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1433 _("Invalid work requirement for NSE service. Exiting.\n"));
1434 GNUNET_SCHEDULER_shutdown ();
1438 GNUNET_CONFIGURATION_get_value_filename (c, "PEER", "PRIVATE_KEY",
1441 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1443 ("%s service is lacking key configuration settings (%s). Exiting.\n"),
1444 "NSE", "peer/privatekey");
1445 GNUNET_SCHEDULER_shutdown ();
1448 #if ENABLE_NSE_HISTOGRAM
1449 if (NULL == (lh = GNUNET_TESTBED_LOGGER_connect (cfg)))
1451 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1452 "Cannot connect to the testbed logger. Exiting.\n");
1453 GNUNET_SCHEDULER_shutdown ();
1458 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL, &shutdown_task,
1460 pk = GNUNET_CRYPTO_ecc_key_create_from_file (keyfile);
1461 GNUNET_free (keyfile);
1462 GNUNET_assert (NULL != pk);
1463 my_private_key = pk;
1464 GNUNET_CRYPTO_ecc_key_get_public (my_private_key, &my_public_key);
1465 GNUNET_CRYPTO_hash (&my_public_key, sizeof (my_public_key),
1466 &my_identity.hashPubKey);
1468 GNUNET_CONFIGURATION_get_value_filename (cfg, "NSE", "PROOFFILE", &proof))
1470 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1472 ("NSE service is lacking key configuration settings. Exiting.\n"));
1473 GNUNET_free (my_private_key);
1474 my_private_key = NULL;
1475 GNUNET_SCHEDULER_shutdown ();
1478 if ((GNUNET_YES != GNUNET_DISK_file_test (proof)) ||
1479 (sizeof (my_proof) !=
1480 GNUNET_DISK_fn_read (proof, &my_proof, sizeof (my_proof))))
1482 GNUNET_free (proof);
1484 GNUNET_SCHEDULER_add_with_priority (GNUNET_SCHEDULER_PRIORITY_IDLE,
1487 peers = GNUNET_CONTAINER_multihashmap_create (128, GNUNET_NO);
1488 GNUNET_SERVER_add_handlers (srv, handlers);
1489 nc = GNUNET_SERVER_notification_context_create (srv, 1);
1490 /* Connect to core service and register core handlers */
1491 coreAPI = GNUNET_CORE_connect (cfg, /* Main configuration */
1492 NULL, /* Closure passed to functions */
1493 &core_init, /* Call core_init once connected */
1494 &handle_core_connect, /* Handle connects */
1495 &handle_core_disconnect, /* Handle disconnects */
1496 NULL, /* Don't want notified about all incoming messages */
1497 GNUNET_NO, /* For header only inbound notification */
1498 NULL, /* Don't want notified about all outbound messages */
1499 GNUNET_NO, /* For header only outbound notification */
1500 core_handlers); /* Register these handlers */
1501 if (NULL == coreAPI)
1503 GNUNET_SCHEDULER_shutdown ();
1506 stats = GNUNET_STATISTICS_create ("nse", cfg);
1511 * The main function for the network size estimation service.
1513 * @param argc number of arguments from the command line
1514 * @param argv command line arguments
1515 * @return 0 ok, 1 on error
1518 main (int argc, char *const *argv)
1520 return (GNUNET_OK ==
1521 GNUNET_SERVICE_run (argc, argv, "nse", GNUNET_SERVICE_OPTION_NONE,
1522 &run, NULL)) ? 0 : 1;
1530 * MINIMIZE heap size (way below 128k) since this process doesn't need much.
1532 void __attribute__ ((constructor)) GNUNET_ARM_memory_init ()
1534 mallopt (M_TRIM_THRESHOLD, 4 * 1024);
1535 mallopt (M_TOP_PAD, 1 * 1024);
1542 /* end of gnunet-service-nse.c */