/* This file is part of GNUnet. (C) 2007, 2008, 2009, 2010 Christian Grothoff (and other contributing authors) GNUnet is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. GNUnet is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNUnet; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /** * @file topology/gnunet-daemon-topology.c * @brief code for maintaining the mesh topology * @author Christian Grothoff */ #include "platform.h" #include "gnunet_constants.h" #include "gnunet_core_service.h" #include "gnunet_protocols.h" #include "gnunet_peerinfo_service.h" #include "gnunet_statistics_service.h" #include "gnunet_transport_service.h" #include "gnunet_util_lib.h" /** * For how long do we blacklist a peer after a failed connection * attempt? This is the baseline factor which is then multiplied by * two to the power of the number of failed attempts. */ #define GREYLIST_AFTER_ATTEMPT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 1) /** * For how long do we blacklist a friend after a failed connection * attempt? This is the baseline factor which is then multiplied by * two to the power of the number of failed attempts. */ #define GREYLIST_AFTER_ATTEMPT_FRIEND GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 2) /** * For how long do we blacklist anyone under any cirumstances at least after a failed connection * attempt? This is the absolute minimum, regardless of what the calculation based on * exponential backoff returns. */ #define GREYLIST_AFTER_ATTEMPT_MIN GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5) /** * For how long do we blacklist anyone under any cirumstances at most after a failed connection * attempt? This is the absolute maximum, regardless of what the calculation based on * exponential back-off returns. */ #define GREYLIST_AFTER_ATTEMPT_MAX GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_HOURS, 1) /** * At what frequency do we sent HELLOs to a peer? */ #define HELLO_ADVERTISEMENT_MIN_FREQUENCY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 5) /** * After what time period do we expire the HELLO Bloom filter? */ #define HELLO_ADVERTISEMENT_MIN_REPEAT_FREQUENCY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_HOURS, 4) /** * Record for neighbours, friends and blacklisted peers. */ struct Peer { /** * Which peer is this entry about? */ struct GNUNET_PeerIdentity pid; /** * Our handle for the request to transmit HELLOs to this peer; NULL * if no such request is pending. */ struct GNUNET_CORE_TransmitHandle *hello_req; /** * Pointer to the HELLO message of this peer; can be NULL. */ struct GNUNET_HELLO_Message *hello; /** * Bloom filter used to mark which peers already got the HELLO * from this peer. */ struct GNUNET_CONTAINER_BloomFilter *filter; /** * Until what time should we not try to connect again * to this peer? */ struct GNUNET_TIME_Absolute greylisted_until; /** * Next time we are allowed to transmit a HELLO to this peer? */ struct GNUNET_TIME_Absolute next_hello_allowed; /** * When should we reset the bloom filter of this entry? */ struct GNUNET_TIME_Absolute filter_expiration; /** * ID of task we use to wait for the time to send the next HELLO * to this peer. */ GNUNET_SCHEDULER_TaskIdentifier hello_delay_task; /** * ID of task we use to clear peers from the greylist. */ GNUNET_SCHEDULER_TaskIdentifier greylist_clean_task; /** * How often have we tried so far? */ unsigned int connect_attempts; /** * Is this peer listed here because he is a friend? */ int is_friend; /** * Are we connected to this peer right now? */ int is_connected; }; /** * Our peerinfo notification context. We use notification * to instantly learn about new peers as they are discovered. */ static struct GNUNET_PEERINFO_NotifyContext *peerinfo_notify; /** * Our configuration. */ static const struct GNUNET_CONFIGURATION_Handle *cfg; /** * Handle to the core API. */ static struct GNUNET_CORE_Handle *handle; /** * Handle to the transport API. */ static struct GNUNET_TRANSPORT_Handle *transport; /** * Identity of this peer. */ static struct GNUNET_PeerIdentity my_identity; /** * All of our friends, all of our current neighbours and all peers for * which we have HELLOs. So pretty much everyone. Maps peer identities * to 'struct Peer *' values. */ static struct GNUNET_CONTAINER_MultiHashMap *peers; /** * Handle for reporting statistics. */ static struct GNUNET_STATISTICS_Handle *stats; /** * Blacklist (NULL if we have none). */ static struct GNUNET_TRANSPORT_Blacklist *blacklist; /** * Task scheduled to try to add peers. */ static GNUNET_SCHEDULER_TaskIdentifier add_task; /** * Flag to disallow non-friend connections (pure F2F mode). */ static int friends_only; /** * Minimum number of friends to have in the * connection set before we allow non-friends. */ static unsigned int minimum_friend_count; /** * Number of peers (friends and others) that we are currently connected to. */ static unsigned int connection_count; /** * Target number of connections. */ static unsigned int target_connection_count; /** * Number of friends that we are currently connected to. */ static unsigned int friend_count; /** * Should the topology daemon try to establish connections? */ static int autoconnect; /** * Function that decides if a connection is acceptable or not. * If we have a blacklist, only friends are allowed, so the check * is rather simple. * * @param cls closure * @param pid peer to approve or disapproave * @return GNUNET_OK if the connection is allowed */ static int blacklist_check (void *cls, const struct GNUNET_PeerIdentity *pid) { struct Peer *pos; pos = GNUNET_CONTAINER_multihashmap_get (peers, &pid->hashPubKey); if ((pos != NULL) && (pos->is_friend == GNUNET_YES)) return GNUNET_OK; GNUNET_STATISTICS_update (stats, gettext_noop ("# peers blacklisted"), 1, GNUNET_NO); return GNUNET_SYSERR; } /** * Whitelist all peers that we blacklisted; we've passed * the minimum number of friends. */ static void whitelist_peers () { if (blacklist != NULL) { GNUNET_TRANSPORT_blacklist_cancel (blacklist); blacklist = NULL; } } /** * Check if an additional connection from the given peer is allowed. * * @param peer connection to check * @return GNUNET_OK if the connection is allowed */ static int is_connection_allowed (struct Peer *peer) { if (0 == memcmp (&my_identity, &peer->pid, sizeof (struct GNUNET_PeerIdentity))) return GNUNET_SYSERR; /* disallow connections to self */ if (peer->is_friend) return GNUNET_OK; if (GNUNET_YES == friends_only) { GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Determined that `%s' is not allowed to connect (not a friend)\n", GNUNET_i2s (&peer->pid)); return GNUNET_SYSERR; } if (friend_count >= minimum_friend_count) return GNUNET_OK; GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Determined that `%s' is not allowed to connect (not enough connected friends)\n", GNUNET_i2s (&peer->pid)); return GNUNET_SYSERR; } /** * Free all resources associated with the given peer. * * @param cls closure (not used) * @param pid identity of the peer * @param value peer to free * @return GNUNET_YES (always: continue to iterate) */ static int free_peer (void *cls, const GNUNET_HashCode * pid, void *value) { struct Peer *pos = value; GNUNET_break (GNUNET_NO == pos->is_connected); GNUNET_break (GNUNET_OK == GNUNET_CONTAINER_multihashmap_remove (peers, pid, pos)); if (pos->hello_req != NULL) GNUNET_CORE_notify_transmit_ready_cancel (pos->hello_req); if (pos->hello_delay_task != GNUNET_SCHEDULER_NO_TASK) GNUNET_SCHEDULER_cancel (pos->hello_delay_task); if (pos->greylist_clean_task != GNUNET_SCHEDULER_NO_TASK) GNUNET_SCHEDULER_cancel (pos->greylist_clean_task); GNUNET_free_non_null (pos->hello); if (pos->filter != NULL) GNUNET_CONTAINER_bloomfilter_free (pos->filter); GNUNET_free (pos); return GNUNET_YES; } /** * Discard peer entries for greylisted peers * where the greylisting has expired. * * @param cls 'struct Peer' to greylist * @param tc scheduler context */ static void remove_from_greylist (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc); /** * Try to connect to the specified peer. * * @param pos peer to connect to */ static void attempt_connect (struct Peer *pos) { struct GNUNET_TIME_Relative rem; if ((connection_count >= target_connection_count) && (friend_count >= minimum_friend_count)) return; if (GNUNET_YES == pos->is_connected) return; if (GNUNET_OK != is_connection_allowed (pos)) return; if (GNUNET_TIME_absolute_get_remaining (pos->greylisted_until).rel_value > 0) return; if (GNUNET_YES == pos->is_friend) rem = GREYLIST_AFTER_ATTEMPT_FRIEND; else rem = GREYLIST_AFTER_ATTEMPT; rem = GNUNET_TIME_relative_multiply (rem, connection_count); rem = GNUNET_TIME_relative_divide (rem, target_connection_count); if (pos->connect_attempts > 30) pos->connect_attempts = 30; rem = GNUNET_TIME_relative_multiply (rem, 1 << (++pos->connect_attempts)); rem = GNUNET_TIME_relative_max (rem, GREYLIST_AFTER_ATTEMPT_MIN); rem = GNUNET_TIME_relative_min (rem, GREYLIST_AFTER_ATTEMPT_MAX); pos->greylisted_until = GNUNET_TIME_relative_to_absolute (rem); if (pos->greylist_clean_task != GNUNET_SCHEDULER_NO_TASK) GNUNET_SCHEDULER_cancel (pos->greylist_clean_task); pos->greylist_clean_task = GNUNET_SCHEDULER_add_delayed (rem, &remove_from_greylist, pos); GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Asking to connect to `%s'\n", GNUNET_i2s (&pos->pid)); GNUNET_STATISTICS_update (stats, gettext_noop ("# connect requests issued to transport"), 1, GNUNET_NO); GNUNET_TRANSPORT_try_connect (transport, &pos->pid); } /** * Discard peer entries for greylisted peers * where the greylisting has expired. * * @param cls 'struct Peer' to greylist * @param tc scheduler context */ static void remove_from_greylist (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct Peer *pos = cls; struct GNUNET_TIME_Relative rem; pos->greylist_clean_task = GNUNET_SCHEDULER_NO_TASK; rem = GNUNET_TIME_absolute_get_remaining (pos->greylisted_until); if (rem.rel_value == 0) { attempt_connect (pos); } else { pos->greylist_clean_task = GNUNET_SCHEDULER_add_delayed (rem, &remove_from_greylist, pos); } if ((GNUNET_NO == pos->is_friend) && (GNUNET_NO == pos->is_connected) && (NULL == pos->hello)) { free_peer (NULL, &pos->pid.hashPubKey, pos); return; } } /** * Create a new entry in the peer list. * * @param peer identity of the new entry * @param hello hello message, can be NULL * @param is_friend is the new entry for a friend? * @return the new entry */ static struct Peer * make_peer (const struct GNUNET_PeerIdentity *peer, const struct GNUNET_HELLO_Message *hello, int is_friend) { struct Peer *ret; ret = GNUNET_malloc (sizeof (struct Peer)); ret->pid = *peer; ret->is_friend = is_friend; if (hello != NULL) { ret->hello = GNUNET_malloc (GNUNET_HELLO_size (hello)); memcpy (ret->hello, hello, GNUNET_HELLO_size (hello)); } GNUNET_break (GNUNET_OK == GNUNET_CONTAINER_multihashmap_put (peers, &peer->hashPubKey, ret, GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY)); return ret; } /** * Setup bloom filter for the given peer entry. * * @param peer entry to initialize */ static void setup_filter (struct Peer *peer) { /* 2^{-5} chance of not sending a HELLO to a peer is * acceptably small (if the filter is 50% full); * 64 bytes of memory are small compared to the rest * of the data structure and would only really become * "useless" once a HELLO has been passed on to ~100 * other peers, which is likely more than enough in * any case; hence 64, 5 as bloomfilter parameters. */ peer->filter = GNUNET_CONTAINER_bloomfilter_init (NULL, 64, 5); peer->filter_expiration = GNUNET_TIME_relative_to_absolute (HELLO_ADVERTISEMENT_MIN_REPEAT_FREQUENCY); /* never send a peer its own HELLO */ GNUNET_CONTAINER_bloomfilter_add (peer->filter, &peer->pid.hashPubKey); } /** * Function to fill send buffer with HELLO. * * @param cls 'struct Peer' of the target peer * @param size number of bytes available in buf * @param buf where the callee should write the message * @return number of bytes written to buf */ static size_t hello_advertising_ready (void *cls, size_t size, void *buf); /** * Closure for 'find_advertisable_hello'. */ struct FindAdvHelloContext { /** * Peer we want to advertise to. */ struct Peer *peer; /** * Where to store the result (peer selected for advertising). */ struct Peer *result; /** * Maximum HELLO size we can use right now. */ size_t max_size; struct GNUNET_TIME_Relative next_adv; }; /** * Find a peer that would be reasonable for advertising. * * @param cls closure * @param pid identity of a peer * @param value 'struct Peer*' for the peer we are considering * @return GNUNET_YES (continue iteration) */ static int find_advertisable_hello (void *cls, const GNUNET_HashCode * pid, void *value) { struct FindAdvHelloContext *fah = cls; struct Peer *pos = value; struct GNUNET_TIME_Relative rst_time; size_t hs; if (pos == fah->peer) return GNUNET_YES; if (pos->hello == NULL) return GNUNET_YES; rst_time = GNUNET_TIME_absolute_get_remaining (pos->filter_expiration); if (0 == rst_time.rel_value) { /* time to discard... */ GNUNET_CONTAINER_bloomfilter_free (pos->filter); setup_filter (pos); } fah->next_adv = GNUNET_TIME_relative_min (rst_time, fah->next_adv); hs = GNUNET_HELLO_size (pos->hello); if (hs > fah->max_size) return GNUNET_YES; if (GNUNET_NO == GNUNET_CONTAINER_bloomfilter_test (pos->filter, &fah->peer->pid.hashPubKey)) fah->result = pos; return GNUNET_YES; } /** * Calculate when we would like to send the next HELLO to this * peer and ask for it. * * @param cls for which peer to schedule the HELLO * @param tc task context */ static void schedule_next_hello (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct Peer *pl = cls; struct FindAdvHelloContext fah; size_t next_want; struct GNUNET_TIME_Relative delay; pl->hello_delay_task = GNUNET_SCHEDULER_NO_TASK; GNUNET_assert (GNUNET_YES == pl->is_connected); if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)) return; /* we're out of here */ if (pl->hello_req != NULL) return; /* did not finish sending the previous one */ /* find applicable HELLOs */ fah.peer = pl; fah.result = NULL; fah.max_size = GNUNET_SERVER_MAX_MESSAGE_SIZE - 1; fah.next_adv = GNUNET_TIME_UNIT_FOREVER_REL; GNUNET_CONTAINER_multihashmap_iterate (peers, &find_advertisable_hello, &fah); pl->hello_delay_task = GNUNET_SCHEDULER_add_delayed (fah.next_adv, &schedule_next_hello, pl); if (fah.result == NULL) return; next_want = GNUNET_HELLO_size (fah.result->hello); delay = GNUNET_TIME_absolute_get_remaining (pl->next_hello_allowed); if (delay.rel_value == 0) { /* now! */ pl->hello_req = GNUNET_CORE_notify_transmit_ready (handle, GNUNET_YES, 0, GNUNET_CONSTANTS_SERVICE_TIMEOUT, &pl->pid, next_want, &hello_advertising_ready, pl); } } /** * Cancel existing requests for sending HELLOs to this peer * and recalculate when we should send HELLOs to it based * on our current state (something changed!). * * @param cls closure, 'struct Peer' to skip, or NULL * @param pid identity of a peer * @param value 'struct Peer*' for the peer * @return GNUNET_YES (always) */ static int reschedule_hellos (void *cls, const GNUNET_HashCode * pid, void *value) { struct Peer *peer = value; struct Peer *skip = cls; if (skip == peer) return GNUNET_YES; if (!peer->is_connected) return GNUNET_YES; if (peer->hello_req != NULL) { GNUNET_CORE_notify_transmit_ready_cancel (peer->hello_req); peer->hello_req = NULL; } if (peer->hello_delay_task != GNUNET_SCHEDULER_NO_TASK) { GNUNET_SCHEDULER_cancel (peer->hello_delay_task); peer->hello_delay_task = GNUNET_SCHEDULER_NO_TASK; } peer->hello_delay_task = GNUNET_SCHEDULER_add_now (&schedule_next_hello, peer); return GNUNET_YES; } /** * Method called whenever a peer connects. * * @param cls closure * @param peer peer identity this notification is about * @param atsi performance data * @param atsi_count number of records in 'atsi' */ static void connect_notify (void *cls, const struct GNUNET_PeerIdentity *peer, const struct GNUNET_ATS_Information *atsi, unsigned int atsi_count) { struct Peer *pos; GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Core told us that we are connecting to `%s'\n", GNUNET_i2s (peer)); if (0 == memcmp (&my_identity, peer, sizeof (struct GNUNET_PeerIdentity))) return; connection_count++; GNUNET_STATISTICS_set (stats, gettext_noop ("# peers connected"), connection_count, GNUNET_NO); pos = GNUNET_CONTAINER_multihashmap_get (peers, &peer->hashPubKey); if (NULL == pos) { pos = make_peer (peer, NULL, GNUNET_NO); GNUNET_break (GNUNET_OK == is_connection_allowed (pos)); } else { GNUNET_assert (GNUNET_NO == pos->is_connected); pos->greylisted_until.abs_value = 0; /* remove greylisting */ } pos->is_connected = GNUNET_YES; pos->connect_attempts = 0; /* re-set back-off factor */ if (pos->is_friend) { if ((friend_count == minimum_friend_count - 1) && (GNUNET_YES != friends_only)) whitelist_peers (); friend_count++; GNUNET_STATISTICS_set (stats, gettext_noop ("# friends connected"), friend_count, GNUNET_NO); } reschedule_hellos (NULL, &peer->hashPubKey, pos); } /** * Try to add more peers to our connection set. * * @param cls closure, not used * @param pid identity of a peer * @param value 'struct Peer*' for the peer * @return GNUNET_YES (continue to iterate) */ static int try_add_peers (void *cls, const GNUNET_HashCode * pid, void *value) { struct Peer *pos = value; attempt_connect (pos); return GNUNET_YES; } /** * Last task run during shutdown. Disconnects us from * the transport and core. * * @param cls unused, NULL * @param tc scheduler context */ static void add_peer_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { add_task = GNUNET_SCHEDULER_NO_TASK; GNUNET_CONTAINER_multihashmap_iterate (peers, &try_add_peers, NULL); } /** * Method called whenever a peer disconnects. * * @param cls closure * @param peer peer identity this notification is about */ static void disconnect_notify (void *cls, const struct GNUNET_PeerIdentity *peer) { struct Peer *pos; if (0 == memcmp (&my_identity, peer, sizeof (struct GNUNET_PeerIdentity))) return; GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Core told us that we disconnected from `%s'\n", GNUNET_i2s (peer)); pos = GNUNET_CONTAINER_multihashmap_get (peers, &peer->hashPubKey); if (NULL == pos) { GNUNET_break (0); return; } if (pos->is_connected != GNUNET_YES) { GNUNET_break (0); return; } pos->is_connected = GNUNET_NO; connection_count--; if (NULL != pos->hello_req) { GNUNET_CORE_notify_transmit_ready_cancel (pos->hello_req); pos->hello_req = NULL; } if (GNUNET_SCHEDULER_NO_TASK != pos->hello_delay_task) { GNUNET_SCHEDULER_cancel (pos->hello_delay_task); pos->hello_delay_task = GNUNET_SCHEDULER_NO_TASK; } GNUNET_STATISTICS_set (stats, gettext_noop ("# peers connected"), connection_count, GNUNET_NO); if (pos->is_friend) { friend_count--; GNUNET_STATISTICS_set (stats, gettext_noop ("# friends connected"), friend_count, GNUNET_NO); } if (((connection_count < target_connection_count) || (friend_count < minimum_friend_count)) && (GNUNET_SCHEDULER_NO_TASK == add_task)) add_task = GNUNET_SCHEDULER_add_now (&add_peer_task, NULL); if ((friend_count < minimum_friend_count) && (blacklist == NULL)) blacklist = GNUNET_TRANSPORT_blacklist (cfg, &blacklist_check, NULL); } /** * Iterator called on each address. * * @param cls flag that we will set if we see any addresses * @param address the address of the peer * @param expiration when will the given address expire * @return GNUNET_SYSERR always, to terminate iteration */ static int address_iterator (void *cls, const struct GNUNET_HELLO_Address *address, struct GNUNET_TIME_Absolute expiration) { int *flag = cls; *flag = GNUNET_YES; return GNUNET_SYSERR; } /** * We've gotten a HELLO from another peer. Consider it for * advertising. * * @param hello the HELLO we got */ static void consider_for_advertising (const struct GNUNET_HELLO_Message *hello) { int have_address; struct GNUNET_PeerIdentity pid; struct GNUNET_TIME_Absolute dt; struct GNUNET_HELLO_Message *nh; struct Peer *peer; uint16_t size; if (GNUNET_OK != GNUNET_HELLO_get_id (hello, &pid)) { GNUNET_break (0); return; } if (0 == memcmp (&pid, &my_identity, sizeof (struct GNUNET_PeerIdentity))) return; /* that's me! */ have_address = GNUNET_NO; GNUNET_HELLO_iterate_addresses (hello, GNUNET_NO, &address_iterator, &have_address); if (GNUNET_NO == have_address) return; /* no point in advertising this one... */ peer = GNUNET_CONTAINER_multihashmap_get (peers, &pid.hashPubKey); if (NULL == peer) { peer = make_peer (&pid, hello, GNUNET_NO); } else if (peer->hello != NULL) { dt = GNUNET_HELLO_equals (peer->hello, hello, GNUNET_TIME_absolute_get ()); if (dt.abs_value == GNUNET_TIME_UNIT_FOREVER_ABS.abs_value) return; /* nothing new here */ } GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Found `%s' from peer `%s' for advertising\n", "HELLO", GNUNET_i2s (&pid)); if (peer->hello != NULL) { nh = GNUNET_HELLO_merge (peer->hello, hello); GNUNET_free (peer->hello); peer->hello = nh; } else { size = GNUNET_HELLO_size (hello); peer->hello = GNUNET_malloc (size); memcpy (peer->hello, hello, size); } if (peer->filter != NULL) GNUNET_CONTAINER_bloomfilter_free (peer->filter); setup_filter (peer); /* since we have a new HELLO to pick from, re-schedule all * HELLO requests that are not bound by the HELLO send rate! */ GNUNET_CONTAINER_multihashmap_iterate (peers, &reschedule_hellos, peer); } /** * PEERINFO calls this function to let us know about a possible peer * that we might want to connect to. * * @param cls closure (not used) * @param peer potential peer to connect to * @param hello HELLO for this peer (or NULL) * @param err_msg NULL if successful, otherwise contains error message */ static void process_peer (void *cls, const struct GNUNET_PeerIdentity *peer, const struct GNUNET_HELLO_Message *hello, const char *err_msg) { struct Peer *pos; if (err_msg != NULL) { GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, _("Error in communication with PEERINFO service: %s\n"), err_msg); GNUNET_PEERINFO_notify_cancel (peerinfo_notify); peerinfo_notify = GNUNET_PEERINFO_notify (cfg, &process_peer, NULL); return; } GNUNET_assert (peer != NULL); if (0 == memcmp (&my_identity, peer, sizeof (struct GNUNET_PeerIdentity))) return; /* that's me! */ if (hello == NULL) { /* free existing HELLO, if any */ pos = GNUNET_CONTAINER_multihashmap_get (peers, &peer->hashPubKey); if (NULL != pos) { GNUNET_free_non_null (pos->hello); pos->hello = NULL; if (pos->filter != NULL) { GNUNET_CONTAINER_bloomfilter_free (pos->filter); pos->filter = NULL; } if ((GNUNET_NO == pos->is_connected) && (GNUNET_NO == pos->is_friend) && (0 == GNUNET_TIME_absolute_get_remaining (pos-> greylisted_until).rel_value)) free_peer (NULL, &pos->pid.hashPubKey, pos); } return; } consider_for_advertising (hello); pos = GNUNET_CONTAINER_multihashmap_get (peers, &peer->hashPubKey); if (pos == NULL) pos = make_peer (peer, hello, GNUNET_NO); GNUNET_assert (NULL != pos); if (GNUNET_YES == pos->is_connected) { GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Already connected to peer `%s'\n", GNUNET_i2s (peer)); return; } if (GNUNET_TIME_absolute_get_remaining (pos->greylisted_until).rel_value > 0) { GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Already tried peer `%s' recently\n", GNUNET_i2s (peer)); return; /* peer still greylisted */ } GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Considering connecting to peer `%s'\n", GNUNET_i2s (peer)); attempt_connect (pos); } /** * Function called after GNUNET_CORE_connect has succeeded * (or failed for good). * * @param cls closure * @param server handle to the server, NULL if we failed * @param my_id ID of this peer, NULL if we failed */ static void core_init (void *cls, struct GNUNET_CORE_Handle *server, const struct GNUNET_PeerIdentity *my_id) { if (server == NULL) { GNUNET_log (GNUNET_ERROR_TYPE_ERROR, _ ("Failed to connect to core service, can not manage topology!\n")); GNUNET_SCHEDULER_shutdown (); return; } handle = server; my_identity = *my_id; GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "I am peer `%s'\n", GNUNET_i2s (my_id)); peerinfo_notify = GNUNET_PEERINFO_notify (cfg, &process_peer, NULL); } /** * Read the friends file. */ static void read_friends_file (const struct GNUNET_CONFIGURATION_Handle *cfg) { char *fn; char *data; size_t pos; struct GNUNET_PeerIdentity pid; uint64_t fsize; struct GNUNET_CRYPTO_HashAsciiEncoded enc; unsigned int entries_found; struct Peer *fl; if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_filename (cfg, "TOPOLOGY", "FRIENDS", &fn)) { GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _("Option `%s' in section `%s' not specified!\n"), "FRIENDS", "TOPOLOGY"); return; } if (GNUNET_OK != GNUNET_DISK_file_test (fn)) GNUNET_DISK_fn_write (fn, NULL, 0, GNUNET_DISK_PERM_USER_READ | GNUNET_DISK_PERM_USER_WRITE); if (GNUNET_OK != GNUNET_DISK_file_size (fn, &fsize, GNUNET_NO, GNUNET_YES)) { if ((friends_only) || (minimum_friend_count > 0)) GNUNET_log (GNUNET_ERROR_TYPE_ERROR, _("Could not read friends list `%s'\n"), fn); GNUNET_free (fn); return; } if (fsize == 0) { GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _("Friends file `%s' is empty.\n"), fn); GNUNET_free (fn); return; } data = GNUNET_malloc_large (fsize); if (data == NULL) { GNUNET_log (GNUNET_ERROR_TYPE_ERROR, _("Failed to read friends list from `%s': out of memory\n"), fn); GNUNET_free (fn); return; } if (fsize != GNUNET_DISK_fn_read (fn, data, fsize)) { GNUNET_log (GNUNET_ERROR_TYPE_ERROR, _("Failed to read friends list from `%s'\n"), fn); GNUNET_free (fn); GNUNET_free (data); return; } entries_found = 0; pos = 0; while ((pos < fsize) && isspace ((unsigned char) data[pos])) pos++; while ((fsize >= sizeof (struct GNUNET_CRYPTO_HashAsciiEncoded)) && (pos <= fsize - sizeof (struct GNUNET_CRYPTO_HashAsciiEncoded))) { memcpy (&enc, &data[pos], sizeof (struct GNUNET_CRYPTO_HashAsciiEncoded)); if (!isspace ((unsigned char) enc.encoding[sizeof (struct GNUNET_CRYPTO_HashAsciiEncoded) - 1])) { GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Syntax error in topology specification at offset %llu, skipping bytes.\n"), (unsigned long long) pos); pos++; while ((pos < fsize) && (!isspace ((unsigned char) data[pos]))) pos++; continue; } enc.encoding[sizeof (struct GNUNET_CRYPTO_HashAsciiEncoded) - 1] = '\0'; if (GNUNET_OK != GNUNET_CRYPTO_hash_from_string ((char *) &enc, &pid.hashPubKey)) { GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Syntax error in topology specification at offset %llu, skipping bytes `%s'.\n"), (unsigned long long) pos, &enc); } else { if (0 != memcmp (&pid, &my_identity, sizeof (struct GNUNET_PeerIdentity))) { entries_found++; fl = make_peer (&pid, NULL, GNUNET_YES); GNUNET_log (GNUNET_ERROR_TYPE_INFO, _("Found friend `%s' in configuration\n"), GNUNET_i2s (&fl->pid)); } else { GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _("Found myself `%s' in friend list (useless, ignored)\n"), GNUNET_i2s (&pid)); } } pos = pos + sizeof (struct GNUNET_CRYPTO_HashAsciiEncoded); while ((pos < fsize) && isspace ((unsigned char) data[pos])) pos++; } GNUNET_free (data); GNUNET_free (fn); GNUNET_STATISTICS_update (stats, gettext_noop ("# friends in configuration"), entries_found, GNUNET_NO); if ((minimum_friend_count > entries_found) && (friends_only == GNUNET_NO)) { GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Fewer friends specified than required by minimum friend count. Will only connect to friends.\n")); } if ((minimum_friend_count > target_connection_count) && (friends_only == GNUNET_NO)) { GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("More friendly connections required than target total number of connections.\n")); } } /** * This function is called whenever an encrypted HELLO message is * received. * * @param cls closure * @param other the other peer involved (sender or receiver, NULL * for loopback messages where we are both sender and receiver) * @param message the actual HELLO message * @param atsi performance data * @param atsi_count number of records in 'atsi' * @return GNUNET_OK to keep the connection open, * GNUNET_SYSERR to close it (signal serious error) */ static int handle_encrypted_hello (void *cls, const struct GNUNET_PeerIdentity *other, const struct GNUNET_MessageHeader *message, const struct GNUNET_ATS_Information *atsi, unsigned int atsi_count) { struct Peer *peer; struct GNUNET_PeerIdentity pid; GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Received encrypted `%s' from peer `%s'", "HELLO", GNUNET_i2s (other)); if (GNUNET_OK != GNUNET_HELLO_get_id ((const struct GNUNET_HELLO_Message *) message, &pid)) { GNUNET_break_op (0); return GNUNET_SYSERR; } GNUNET_STATISTICS_update (stats, gettext_noop ("# HELLO messages received"), 1, GNUNET_NO); peer = GNUNET_CONTAINER_multihashmap_get (peers, &pid.hashPubKey); if (NULL == peer) { if ((GNUNET_YES == friends_only) || (friend_count < minimum_friend_count)) return GNUNET_OK; } else { if ((GNUNET_YES != peer->is_friend) && (GNUNET_YES == friends_only)) return GNUNET_OK; if ((GNUNET_YES != peer->is_friend) && (friend_count < minimum_friend_count)) return GNUNET_OK; } if (transport != NULL) GNUNET_TRANSPORT_offer_hello (transport, message, NULL, NULL); return GNUNET_OK; } /** * Function to fill send buffer with HELLO. * * @param cls 'struct Peer' of the target peer * @param size number of bytes available in buf * @param buf where the callee should write the message * @return number of bytes written to buf */ static size_t hello_advertising_ready (void *cls, size_t size, void *buf) { struct Peer *pl = cls; struct FindAdvHelloContext fah; size_t want; pl->hello_req = NULL; GNUNET_assert (GNUNET_YES == pl->is_connected); /* find applicable HELLOs */ fah.peer = pl; fah.result = NULL; fah.max_size = size; fah.next_adv = GNUNET_TIME_UNIT_FOREVER_REL; GNUNET_CONTAINER_multihashmap_iterate (peers, &find_advertisable_hello, &fah); want = 0; if (fah.result != NULL) { want = GNUNET_HELLO_size (fah.result->hello); GNUNET_assert (want <= size); memcpy (buf, fah.result->hello, want); GNUNET_CONTAINER_bloomfilter_add (fah.result->filter, &pl->pid.hashPubKey); GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Sending `%s' with %u bytes", "HELLO", (unsigned int) want); GNUNET_STATISTICS_update (stats, gettext_noop ("# HELLO messages gossipped"), 1, GNUNET_NO); } if (pl->hello_delay_task != GNUNET_SCHEDULER_NO_TASK) GNUNET_SCHEDULER_cancel (pl->hello_delay_task); pl->next_hello_allowed = GNUNET_TIME_relative_to_absolute (HELLO_ADVERTISEMENT_MIN_FREQUENCY); pl->hello_delay_task = GNUNET_SCHEDULER_add_now (&schedule_next_hello, pl); return want; } /** * Last task run during shutdown. Disconnects us from * the transport and core. * * @param cls unused, NULL * @param tc scheduler context */ static void cleaning_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { if (NULL != peerinfo_notify) { GNUNET_PEERINFO_notify_cancel (peerinfo_notify); peerinfo_notify = NULL; } GNUNET_TRANSPORT_disconnect (transport); transport = NULL; if (handle != NULL) { GNUNET_CORE_disconnect (handle); handle = NULL; } whitelist_peers (); if (GNUNET_SCHEDULER_NO_TASK != add_task) { GNUNET_SCHEDULER_cancel (add_task); add_task = GNUNET_SCHEDULER_NO_TASK; } GNUNET_CONTAINER_multihashmap_iterate (peers, &free_peer, NULL); GNUNET_CONTAINER_multihashmap_destroy (peers); peers = NULL; if (stats != NULL) { GNUNET_STATISTICS_destroy (stats, GNUNET_NO); stats = NULL; } } /** * Main function that will be run. * * @param cls closure * @param args remaining command-line arguments * @param cfgfile name of the configuration file used (for saving, can be NULL!) * @param c configuration */ static void run (void *cls, char *const *args, const char *cfgfile, const struct GNUNET_CONFIGURATION_Handle *c) { static struct GNUNET_CORE_MessageHandler handlers[] = { {&handle_encrypted_hello, GNUNET_MESSAGE_TYPE_HELLO, 0}, {NULL, 0, 0} }; unsigned long long opt; cfg = c; stats = GNUNET_STATISTICS_create ("topology", cfg); autoconnect = GNUNET_CONFIGURATION_get_value_yesno (cfg, "TOPOLOGY", "AUTOCONNECT"); friends_only = GNUNET_CONFIGURATION_get_value_yesno (cfg, "TOPOLOGY", "FRIENDS-ONLY"); if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_number (cfg, "TOPOLOGY", "MINIMUM-FRIENDS", &opt)) opt = 0; minimum_friend_count = (unsigned int) opt; if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_number (cfg, "TOPOLOGY", "TARGET-CONNECTION-COUNT", &opt)) opt = 16; target_connection_count = (unsigned int) opt; peers = GNUNET_CONTAINER_multihashmap_create (target_connection_count * 2); if ((friends_only == GNUNET_YES) || (minimum_friend_count > 0)) read_friends_file (cfg); GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Topology would like %u connections with at least %u friends (%s)\n", target_connection_count, minimum_friend_count, autoconnect ? "autoconnect enabled" : "autoconnect disabled"); if ((friend_count < minimum_friend_count) && (blacklist == NULL)) blacklist = GNUNET_TRANSPORT_blacklist (cfg, &blacklist_check, NULL); transport = GNUNET_TRANSPORT_connect (cfg, NULL, NULL, NULL, NULL, NULL); handle = GNUNET_CORE_connect (cfg, 1, NULL, &core_init, &connect_notify, &disconnect_notify, NULL, GNUNET_NO, NULL, GNUNET_NO, handlers); GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL, &cleaning_task, NULL); if (NULL == transport) { GNUNET_log (GNUNET_ERROR_TYPE_ERROR, _("Failed to connect to `%s' service.\n"), "transport"); GNUNET_SCHEDULER_shutdown (); return; } if (NULL == handle) { GNUNET_log (GNUNET_ERROR_TYPE_ERROR, _("Failed to connect to `%s' service.\n"), "core"); GNUNET_SCHEDULER_shutdown (); return; } } /** * The main function for the topology daemon. * * @param argc number of arguments from the command line * @param argv command line arguments * @return 0 ok, 1 on error */ int main (int argc, char *const *argv) { static const struct GNUNET_GETOPT_CommandLineOption options[] = { GNUNET_GETOPT_OPTION_END }; int ret; ret = (GNUNET_OK == GNUNET_PROGRAM_run (argc, argv, "gnunet-daemon-topology", _ ("GNUnet topology control (maintaining P2P mesh and F2F constraints)"), options, &run, NULL)) ? 0 : 1; return ret; } /* end of gnunet-daemon-topology.c */