* * This message is followed by our transport address that the PING tried * to confirm (if we liked it). The address can be empty (zero bytes) * if the PING had not address either (and we received the request via * a connection that we initiated). */ struct TransportPongMessage { /** * Type will be #GNUNET_MESSAGE_TYPE_TRANSPORT_PONG */ struct GNUNET_MessageHeader header; /** * Challenge code from PING (showing freshness). Not part of what * is signed so that we can re-use signatures. */ uint32_t challenge GNUNET_PACKED; /** * Signature. */ struct GNUNET_CRYPTO_EddsaSignature signature; /** * #GNUNET_SIGNATURE_PURPOSE_TRANSPORT_PONG_OWN to confirm that this is a * plausible address for the signing peer. */ struct GNUNET_CRYPTO_EccSignaturePurpose purpose; /** * When does this signature expire? */ struct GNUNET_TIME_AbsoluteNBO expiration; /** * Size of address appended to this message (part of what is * being signed, hence not redundant). */ uint32_t addrlen GNUNET_PACKED; }; GNUNET_NETWORK_STRUCT_END /** * Information about an address under validation */ struct ValidationEntry { /** * The address. */ struct GNUNET_HELLO_Address *address; /** * Handle to the blacklist check (if we're currently in it). */ struct GST_BlacklistCheck *bc; /** * Cached PONG signature */ struct GNUNET_CRYPTO_EddsaSignature pong_sig_cache; /** * ID of task that will clean up this entry if nothing happens. */ struct GNUNET_SCHEDULER_Task *timeout_task; /** * ID of task that will trigger address revalidation. */ struct GNUNET_SCHEDULER_Task *revalidation_task; /** * At what time did we send the latest validation request (PING)? */ struct GNUNET_TIME_Absolute send_time; /** * At what time do we send the next validation request (PING)? */ struct GNUNET_TIME_Absolute next_validation; /** * Until when is this address valid? * ZERO if it is not currently considered valid. */ struct GNUNET_TIME_Absolute valid_until; /** * Until when is the cached PONG signature valid? * ZERO if it is not currently considered valid. */ struct GNUNET_TIME_Absolute pong_sig_valid_until; /** * How long until we can try to validate this address again? * FOREVER if the address is for an unsupported plugin (from PEERINFO) * ZERO if the address is considered valid (no validation needed) * otherwise a time in the future if we're currently denying re-validation */ struct GNUNET_TIME_Absolute revalidation_block; /** * Last observed latency for this address (round-trip), delay between * last PING sent and PONG received; FOREVER if we never got a PONG. */ struct GNUNET_TIME_Relative latency; /** * Current state of this validation entry */ enum GNUNET_TRANSPORT_ValidationState state; /** * Challenge number we used. */ uint32_t challenge; /** * When passing the address in #add_valid_peer_address(), did we * copy the address to the HELLO yet? */ int copied; /** * Are we currently using this address for a connection? */ int in_use; /** * Are we expecting a PONG message for this validation entry? */ int expecting_pong; /** * Is this address known to ATS as valid right now? */ int known_to_ats; /** * Which network type does our address belong to? */ enum GNUNET_ATS_Network_Type network; }; /** * Map of PeerIdentities to 'struct ValidationEntry*'s (addresses * of the given peer that we are currently validating, have validated * or are blocked from re-validation for a while). */ static struct GNUNET_CONTAINER_MultiPeerMap *validation_map; /** * Context for peerinfo iteration. */ static struct GNUNET_PEERINFO_NotifyContext *pnc; /** * Minimum delay between to validations */ static struct GNUNET_TIME_Relative validation_delay; /** * Number of validations running; any PING that was not yet * matched by a PONG and for which we have not yet hit the * timeout is considered a running 'validation'. */ static unsigned int validations_running; /** * Validition fast start threshold */ static unsigned int validations_fast_start_threshold; /** * When is next validation allowed */ static struct GNUNET_TIME_Absolute validation_next; /** * Context for the validation entry match function. */ struct ValidationEntryMatchContext { /** * Where to store the result? */ struct ValidationEntry *ve; /** * Address we're interested in. */ const struct GNUNET_HELLO_Address *address; }; /** * Provide an update on the `validation_map` map size to statistics. * This function should be called whenever the `validation_map` * is changed. */ static void publish_ve_stat_update () { GNUNET_STATISTICS_set (GST_stats, gettext_noop ("# Addresses in validation map"), GNUNET_CONTAINER_multipeermap_size (validation_map), GNUNET_NO); } /** * Iterate over validation entries until a matching one is found. * * @param cls the `struct ValidationEntryMatchContext *` * @param key peer identity (unused) * @param value a `struct ValidationEntry *` to match * @return #GNUNET_YES if the entry does not match, * #GNUNET_NO if the entry does match */ static int validation_entry_match (void *cls, const struct GNUNET_PeerIdentity *key, void *value) { struct ValidationEntryMatchContext *vemc = cls; struct ValidationEntry *ve = value; if (0 == GNUNET_HELLO_address_cmp (ve->address, vemc->address)) { vemc->ve = ve; return GNUNET_NO; } return GNUNET_YES; } /** * A validation entry changed. Update the state and notify * monitors. * * @param ve validation entry that changed * @param state new state */ static void validation_entry_changed (struct ValidationEntry *ve, enum GNUNET_TRANSPORT_ValidationState state) { ve->state = state; } /** * Iterate over validation entries and free them. * * @param cls (unused) * @param key peer identity (unused) * @param value a `struct ValidationEntry *` to clean up * @return #GNUNET_YES (continue to iterate) */ static int cleanup_validation_entry (void *cls, const struct GNUNET_PeerIdentity *key, void *value) { struct ValidationEntry *ve = value; ve->next_validation = GNUNET_TIME_UNIT_ZERO_ABS; ve->valid_until = GNUNET_TIME_UNIT_ZERO_ABS; /* Notify about deleted entry */ validation_entry_changed (ve, GNUNET_TRANSPORT_VS_REMOVE); if (NULL != ve->bc) { GST_blacklist_test_cancel (ve->bc); ve->bc = NULL; } GNUNET_break (GNUNET_OK == GNUNET_CONTAINER_multipeermap_remove (validation_map, &ve->address->peer, ve)); publish_ve_stat_update (); if (GNUNET_YES == ve->known_to_ats) { GST_ats_expire_address (ve->address); GNUNET_assert (GNUNET_NO == GST_ats_is_known_no_session (ve->address)); ve->known_to_ats = GNUNET_NO; } GNUNET_HELLO_address_free (ve->address); if (NULL != ve->timeout_task) { GNUNET_SCHEDULER_cancel (ve->timeout_task); ve->timeout_task = NULL; } if (NULL != ve->revalidation_task) { GNUNET_SCHEDULER_cancel (ve->revalidation_task); ve->revalidation_task = NULL; } if ( (GNUNET_YES == ve->expecting_pong) && (validations_running > 0) ) { validations_running--; GNUNET_STATISTICS_set (GST_stats, gettext_noop ("# validations running"), validations_running, GNUNET_NO); } GNUNET_free (ve); return GNUNET_OK; } /** * Address validation cleanup task. Assesses if the record is no * longer valid and then possibly triggers its removal. * * @param cls the `struct ValidationEntry` */ static void timeout_hello_validation (void *cls) { struct ValidationEntry *ve = cls; struct GNUNET_TIME_Absolute max; struct GNUNET_TIME_Relative left; ve->timeout_task = NULL; /* For valid addresses, we want to wait until the expire; for addresses under PING validation, we want to wait until we give up on the PING */ max = GNUNET_TIME_absolute_max (ve->valid_until, ve->revalidation_block); left = GNUNET_TIME_absolute_get_remaining (max); if (left.rel_value_us > 0) { /* We should wait a bit longer. This happens when address lifetimes are extended due to successful validations. */ ve->timeout_task = GNUNET_SCHEDULER_add_delayed (left, &timeout_hello_validation, ve); return; } GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# address records discarded (timeout)"), 1, GNUNET_NO); cleanup_validation_entry (NULL, &ve->address->peer, ve); } /** * Function called with the result from blacklisting. * Send a PING to the other peer if a communication is allowed. * * @param cls our `struct ValidationEntry` * @param pid identity of the other peer * @param address_null address associated with the request, always NULL * @param session_null session associated with the request, always NULL * @param result #GNUNET_OK if the connection is allowed, * #GNUNET_NO if not, * #GNUNET_SYSERR if operation was aborted */ static void transmit_ping_if_allowed (void *cls, const struct GNUNET_PeerIdentity *pid, const struct GNUNET_HELLO_Address *address_null, struct GNUNET_ATS_Session *session_null, int result) { struct ValidationEntry *ve = cls; struct TransportPingMessage ping; struct GNUNET_TRANSPORT_PluginFunctions *papi; struct GNUNET_TIME_Absolute next; const struct GNUNET_MessageHeader *hello; ssize_t ret; size_t tsize; size_t slen; uint16_t hsize; struct GNUNET_ATS_Session *session; ve->bc = NULL; if (GNUNET_OK != result) { GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Blacklist denies sending PING to `%s' `%s' `%s'\n", GNUNET_i2s (pid), GST_plugins_a2s (ve->address), ve->address->transport_name); GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# address records discarded (blacklist)"), 1, GNUNET_NO); cleanup_validation_entry (NULL, pid, ve); return; } hello = GST_hello_get (); GNUNET_assert (NULL != hello); slen = strlen (ve->address->transport_name) + 1; hsize = ntohs (hello->size); tsize = sizeof (struct TransportPingMessage) + ve->address->address_length + slen + hsize; ping.header.size = htons (sizeof (struct TransportPingMessage) + ve->address->address_length + slen); ping.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_PING); ping.challenge = htonl (ve->challenge); ping.target = *pid; if (tsize >= GNUNET_MAX_MESSAGE_SIZE) { GNUNET_break (0); hsize = 0; tsize = sizeof (struct TransportPingMessage) + ve->address->address_length + slen + hsize; } { char message_buf[tsize] GNUNET_ALIGN; GNUNET_memcpy (message_buf, hello, hsize); GNUNET_memcpy (&message_buf[hsize], &ping, sizeof (struct TransportPingMessage)); GNUNET_memcpy (&message_buf[sizeof (struct TransportPingMessage) + hsize], ve->address->transport_name, slen); GNUNET_memcpy (&message_buf[sizeof (struct TransportPingMessage) + slen + hsize], ve->address->address, ve->address->address_length); papi = GST_plugins_find (ve->address->transport_name); GNUNET_assert (NULL != papi); session = papi->get_session (papi->cls, ve->address); if (NULL == session) { /* Could not get a valid session */ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Failed to get session to send PING to `%s' at `%s'\n", GNUNET_i2s (pid), GST_plugins_a2s (ve->address)); return; } ret = papi->send (papi->cls, session, message_buf, tsize, PING_PRIORITY, ACCEPTABLE_PING_DELAY, NULL, NULL); if (-1 == ret) { GNUNET_log (GNUNET_ERROR_TYPE_INFO, "Failed to send PING to `%s' at `%s'\n", GNUNET_i2s (pid), GST_plugins_a2s (ve->address)); return; } GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Transmitted plain PING to `%s' `%s' `%s'\n", GNUNET_i2s (pid), GST_plugins_a2s (ve->address), ve->address->transport_name); ve->network = papi->get_network (papi->cls, session); GNUNET_break (GNUNET_ATS_NET_UNSPECIFIED != ve->network); GST_neighbours_notify_data_sent (ve->address, session, tsize); next = GNUNET_TIME_relative_to_absolute (validation_delay); validation_next = GNUNET_TIME_absolute_max (next, validation_next); ve->send_time = GNUNET_TIME_absolute_get (); GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# PINGs for address validation sent"), 1, GNUNET_NO); ve->expecting_pong = GNUNET_YES; validations_running++; GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Validation started, %u validation processes running\n", validations_running); GNUNET_STATISTICS_set (GST_stats, gettext_noop ("# validations running"), validations_running, GNUNET_NO); /* Notify about PING sent */ validation_entry_changed (ve, GNUNET_TRANSPORT_VS_UPDATE); } } /** * Do address validation again to keep address valid. * * @param cls the `struct ValidationEntry` */ static void revalidate_address (void *cls) { struct ValidationEntry *ve = cls; struct GNUNET_TIME_Relative canonical_delay; struct GNUNET_TIME_Relative delay; struct GNUNET_TIME_Relative blocked_for; struct GST_BlacklistCheck *bc; uint32_t rdelay; ve->revalidation_task = NULL; delay = GNUNET_TIME_absolute_get_remaining (ve->revalidation_block); /* Considering current connectivity situation, what is the maximum block period permitted? */ if (GNUNET_YES == ve->in_use) canonical_delay = CONNECTED_PING_FREQUENCY; else if (GNUNET_TIME_absolute_get_remaining (ve->valid_until).rel_value_us > 0) canonical_delay = VALIDATED_PING_FREQUENCY; else canonical_delay = UNVALIDATED_PING_KEEPALIVE; /* Use delay that is MIN of original delay and possibly adjusted new maximum delay (which may be lower); the real delay is originally randomized between "canonical_delay" and "2 * canonical_delay", so continue to permit that window for the operation. */ delay = GNUNET_TIME_relative_min (delay, GNUNET_TIME_relative_multiply (canonical_delay, 2)); ve->revalidation_block = GNUNET_TIME_relative_to_absolute (delay); if (delay.rel_value_us > 0) { /* should wait a bit longer */ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Waiting for %s longer before (re)validating address `%s'\n", GNUNET_STRINGS_relative_time_to_string (delay, GNUNET_YES), GST_plugins_a2s (ve->address)); ve->revalidation_task = GNUNET_SCHEDULER_add_delayed (delay, &revalidate_address, ve); ve->next_validation = GNUNET_TIME_relative_to_absolute (delay); return; } /* check if globally we have too many active validations at a too high rate, if so, delay ours */ blocked_for = GNUNET_TIME_absolute_get_remaining (validation_next); if ( (validations_running > validations_fast_start_threshold) && (blocked_for.rel_value_us > 0) ) { /* Validations are blocked, have to wait for blocked_for time */ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Validations blocked for another %s, delaying validating address `%s'\n", GNUNET_STRINGS_relative_time_to_string (blocked_for, GNUNET_YES), GST_plugins_a2s (ve->address)); GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# validations delayed by global throttle"), 1, GNUNET_NO); ve->revalidation_task = GNUNET_SCHEDULER_add_delayed (blocked_for, &revalidate_address, ve); ve->next_validation = GNUNET_TIME_relative_to_absolute (blocked_for); return; } /* We are good to go; remember to not go again for `canonical_delay` time; add up to `canonical_delay` to randomize start time */ ve->revalidation_block = GNUNET_TIME_relative_to_absolute (canonical_delay); /* schedule next PINGing with some extra random delay to avoid synchronous re-validations */ rdelay = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, canonical_delay.rel_value_us); delay = GNUNET_TIME_relative_add (canonical_delay, GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MICROSECONDS, rdelay)); GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Validating now, next scheduled for %s, now validating address `%s'\n", GNUNET_STRINGS_relative_time_to_string (blocked_for, GNUNET_YES), GST_plugins_a2s (ve->address)); ve->revalidation_task = GNUNET_SCHEDULER_add_delayed (delay, &revalidate_address, ve); ve->next_validation = GNUNET_TIME_relative_to_absolute (delay); /* start PINGing by checking blacklist */ GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# address revalidations started"), 1, GNUNET_NO); if (NULL != ve->bc) { GST_blacklist_test_cancel (ve->bc); ve->bc = NULL; } bc = GST_blacklist_test_allowed (&ve->address->peer, ve->address->transport_name, &transmit_ping_if_allowed, ve, NULL, NULL); if (NULL != bc) { /* If transmit_ping_if_allowed was already called it may have freed ve, * so only set ve->bc if it has not been called. */ ve->bc = bc; } } /** * Find a ValidationEntry entry for the given neighbour that matches * the given address and transport. If none exists, create one (but * without starting any validation). * * @param address address to find * @return validation entry matching the given specifications, NULL * if we don't have an existing entry and no public key was given */ static struct ValidationEntry * find_validation_entry (const struct GNUNET_HELLO_Address *address) { struct ValidationEntryMatchContext vemc; struct ValidationEntry *ve; vemc.ve = NULL; vemc.address = address; GNUNET_CONTAINER_multipeermap_get_multiple (validation_map, &address->peer, &validation_entry_match, &vemc); if (NULL != (ve = vemc.ve)) return ve; GNUNET_assert (GNUNET_NO == GST_ats_is_known_no_session (address)); ve = GNUNET_new (struct ValidationEntry); ve->in_use = GNUNET_SYSERR; /* not defined */ ve->address = GNUNET_HELLO_address_copy (address); ve->pong_sig_valid_until = GNUNET_TIME_UNIT_ZERO_ABS; memset (&ve->pong_sig_cache, '\0', sizeof (struct GNUNET_CRYPTO_EddsaSignature)); ve->latency = GNUNET_TIME_UNIT_FOREVER_REL; ve->challenge = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX); ve->timeout_task = GNUNET_SCHEDULER_add_delayed (UNVALIDATED_PING_KEEPALIVE, &timeout_hello_validation, ve); GNUNET_CONTAINER_multipeermap_put (validation_map, &address->peer, ve, GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE); publish_ve_stat_update (); validation_entry_changed (ve, GNUNET_TRANSPORT_VS_NEW); return ve; } /** * Iterator which adds the given address to the set of validated * addresses. * * @param cls original HELLO message * @param address the address * @param expiration expiration time * @return #GNUNET_OK (keep the address), could return * #GNUNET_NO (delete address, but this is ignored); * #GNUNET_SYSERR would abort iteration (but we always iterate all) */ static int add_valid_address (void *cls, const struct GNUNET_HELLO_Address *address, struct GNUNET_TIME_Absolute expiration) { const struct GNUNET_HELLO_Message *hello = cls; struct ValidationEntry *ve; struct GNUNET_PeerIdentity pid; struct GNUNET_ATS_Properties prop; struct GNUNET_TRANSPORT_PluginFunctions *papi; if (0 == GNUNET_TIME_absolute_get_remaining (expiration).rel_value_us) return GNUNET_OK; /* expired */ if (GNUNET_OK != GNUNET_HELLO_get_id (hello, &pid)) { GNUNET_break (0); return GNUNET_OK; /* invalid HELLO !? */ } if (NULL == (papi = GST_plugins_find (address->transport_name))) { /* might have been valid in the past, but we don't have that plugin loaded right now */ return GNUNET_OK; } if (NULL == papi->address_to_string (papi->cls, address->address, address->address_length)) { /* Why do we try to add an ill-formed address? */ GNUNET_break (0); GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Address with %u bytes for plugin %s and peer %s is malformed\n", (unsigned int) address->address_length, address->transport_name, GNUNET_i2s (&pid)); return GNUNET_OK; } ve = find_validation_entry (address); ve->network = papi->get_network_for_address (papi->cls, address); GNUNET_break (GNUNET_ATS_NET_UNSPECIFIED != ve->network); ve->valid_until = GNUNET_TIME_absolute_max (ve->valid_until, expiration); if (NULL == ve->revalidation_task) { GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Starting revalidations for valid address `%s'\n", GST_plugins_a2s (ve->address)); ve->next_validation = GNUNET_TIME_absolute_get(); ve->revalidation_task = GNUNET_SCHEDULER_add_now (&revalidate_address, ve); } validation_entry_changed (ve, GNUNET_TRANSPORT_VS_UPDATE); memset (&prop, 0, sizeof (prop)); prop.scope = ve->network; prop.delay = GNUNET_TIME_relative_divide (ve->latency, 2); if (GNUNET_YES != ve->known_to_ats) { ve->known_to_ats = GNUNET_YES; GST_ats_add_address (address, &prop); GNUNET_assert (GNUNET_YES == GST_ats_is_known_no_session (ve->address)); } return GNUNET_OK; } /** * Function called for any HELLO known to PEERINFO. * * @param cls unused (NULL) * @param peer id of the peer, NULL for last call (during iteration, * as we are monitoring, this should never happen) * @param hello hello message for the peer (can be NULL) * @param err_msg error message */ static void process_peerinfo_hello (void *cls, const struct GNUNET_PeerIdentity *peer, const struct GNUNET_HELLO_Message *hello, const char *err_msg) { GNUNET_assert (NULL != peer); if (NULL == hello) return; if (0 == memcmp (&GST_my_identity, peer, sizeof (struct GNUNET_PeerIdentity))) { /* Peerinfo returned own identity, skip validation */ return; } GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Handling HELLO for peer `%s'\n", GNUNET_i2s (peer)); GNUNET_assert (NULL == GNUNET_HELLO_iterate_addresses (hello, GNUNET_NO, &add_valid_address, (void *) hello)); } /** * Start the validation subsystem. * * @param max_fds maximum number of fds to use */ void GST_validation_start (unsigned int max_fds) { /** * Initialization for validation throttling * * We have a maximum number max_fds of connections we can use for validation * We monitor the number of validations in parallel and start to throttle it * when doing to many validations in parallel: * if (running validations < (max_fds / 2)) * - "fast start": run validation immediately * - have delay of (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT.rel_value_us) / (max_fds / 2) * (300 sec / ~150 == ~2 sec.) between two validations */ validation_next = GNUNET_TIME_absolute_get(); validation_delay.rel_value_us = (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT.rel_value_us) / (max_fds / 2); validations_fast_start_threshold = (max_fds / 2); validations_running = 0; GNUNET_STATISTICS_set (GST_stats, gettext_noop ("# validations running"), validations_running, GNUNET_NO); GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Validation uses a fast start threshold of %u connections and a delay of %s\n", validations_fast_start_threshold, GNUNET_STRINGS_relative_time_to_string (validation_delay, GNUNET_YES)); validation_map = GNUNET_CONTAINER_multipeermap_create (VALIDATION_MAP_SIZE, GNUNET_NO); pnc = GNUNET_PEERINFO_notify (GST_cfg, GNUNET_YES, &process_peerinfo_hello, NULL); } /** * Stop the validation subsystem. */ void GST_validation_stop () { GNUNET_CONTAINER_multipeermap_iterate (validation_map, &cleanup_validation_entry, NULL); GNUNET_CONTAINER_multipeermap_destroy (validation_map); validation_map = NULL; GNUNET_PEERINFO_notify_cancel (pnc); } /** * Send the given PONG to the given address. * * @param cls the PONG message * @param valid_until is ZERO if we never validated the address, * otherwise a time up to when we consider it (or was) valid * @param validation_block is FOREVER if the address is for an unsupported plugin (from PEERINFO) * is ZERO if the address is considered valid (no validation needed) * otherwise a time in the future if we're currently denying re-validation * @param address target address */ static void multicast_pong (void *cls, struct GNUNET_TIME_Absolute valid_until, struct GNUNET_TIME_Absolute validation_block, const struct GNUNET_HELLO_Address *address) { struct TransportPongMessage *pong = cls; struct GNUNET_TRANSPORT_PluginFunctions *papi; struct GNUNET_ATS_Session *session; papi = GST_plugins_find (address->transport_name); if (NULL == papi) { GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Plugin %s not supported, cannot send PONG\n", address->transport_name); return; } GNUNET_assert (NULL != papi->send); GNUNET_assert (NULL != papi->get_session); session = papi->get_session(papi->cls, address); if (NULL == session) { GNUNET_break (0); return; } GST_ats_new_session (address, session); papi->send (papi->cls, session, (const char *) pong, ntohs (pong->header.size), PONG_PRIORITY, ACCEPTABLE_PING_DELAY, NULL, NULL); GST_neighbours_notify_data_sent (address, session, pong->header.size); } /** * We've received a PING. If appropriate, generate a PONG. * * @param sender peer sending the PING * @param hdr the PING * @param sender_address the sender address as we got it * @param session session we got the PING from * @return #GNUNET_OK if the message was fine, #GNUNET_SYSERR on serious error */ int GST_validation_handle_ping (const struct GNUNET_PeerIdentity *sender, const struct GNUNET_MessageHeader *hdr, const struct GNUNET_HELLO_Address *sender_address, struct GNUNET_ATS_Session *session) { const struct TransportPingMessage *ping; struct TransportPongMessage *pong; struct GNUNET_TRANSPORT_PluginFunctions *papi; struct GNUNET_CRYPTO_EddsaSignature *sig_cache; struct GNUNET_TIME_Absolute *sig_cache_exp; const char *addr; const char *addrend; char *plugin_name; char *pos; size_t len_address; size_t len_plugin; ssize_t ret; struct GNUNET_HELLO_Address address; if (0 == memcmp (&GST_my_identity, sender, sizeof (struct GNUNET_PeerIdentity))) return GNUNET_OK; /* our own, ignore! */ if (ntohs (hdr->size) < sizeof (struct TransportPingMessage)) { GNUNET_break_op (0); return GNUNET_SYSERR; } ping = (const struct TransportPingMessage *) hdr; if (0 != memcmp (&ping->target, &GST_my_identity, sizeof (struct GNUNET_PeerIdentity))) { GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# PING message for different peer received"), 1, GNUNET_NO); return GNUNET_SYSERR; } GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# PING messages received"), 1, GNUNET_NO); addr = (const char *) &ping[1]; len_address = ntohs (hdr->size) - sizeof (struct TransportPingMessage); /* peer wants to confirm that this is one of our addresses, this is what is * used for address validation */ sig_cache = NULL; sig_cache_exp = NULL; papi = NULL; if (len_address > 0) { addrend = memchr (addr, '\0', len_address); if (NULL == addrend) { GNUNET_break_op (0); return GNUNET_SYSERR; } addrend++; len_plugin = strlen (addr) + 1; len_address -= len_plugin; address.local_info = GNUNET_HELLO_ADDRESS_INFO_NONE; address.address = addrend; address.address_length = len_address; address.transport_name = addr; address.peer = GST_my_identity; if (NULL == address.transport_name) { GNUNET_break (0); } if (0 != strstr (address.transport_name, "_client")) { plugin_name = GNUNET_strdup (address.transport_name); pos = strstr (plugin_name, "_client"); GNUNET_assert (NULL != pos); GNUNET_snprintf (pos, strlen ("_server") + 1, "%s", "_server"); } else plugin_name = GNUNET_strdup (address.transport_name); if (NULL == (papi = GST_plugins_find (plugin_name))) { /* we don't have the plugin for this address */ GNUNET_log (GNUNET_ERROR_TYPE_INFO, _("Plugin `%s' not available, cannot confirm having this address\n"), plugin_name); GNUNET_free (plugin_name); return GNUNET_SYSERR; } GNUNET_free (plugin_name); if (GNUNET_OK != papi->check_address (papi->cls, addrend, len_address)) { GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# failed address checks during validation"), 1, GNUNET_NO); GNUNET_log (GNUNET_ERROR_TYPE_INFO, _("Address `%s' is not one of my addresses, not confirming PING\n"), GST_plugins_a2s (&address)); return GNUNET_SYSERR; } else { GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# successful address checks during validation"), 1, GNUNET_NO); GNUNET_log (GNUNET_ERROR_TYPE_INFO, "Address `%s' is one of my addresses, confirming PING\n", GST_plugins_a2s (&address)); } if (GNUNET_YES != GST_hello_test_address (&address, &sig_cache, &sig_cache_exp)) { GNUNET_log (GNUNET_ERROR_TYPE_INFO, _("Not confirming PING from peer `%s' with address `%s' since I cannot confirm having this address.\n"), GNUNET_i2s (sender), GST_plugins_a2s (&address)); return GNUNET_SYSERR; } } else { addrend = NULL; /* make gcc happy */ len_plugin = 0; static struct GNUNET_CRYPTO_EddsaSignature no_address_signature; static struct GNUNET_TIME_Absolute no_address_signature_expiration; sig_cache = &no_address_signature; sig_cache_exp = &no_address_signature_expiration; } GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "I am `%s', sending PONG to peer `%s'\n", GNUNET_i2s_full (&GST_my_identity), GNUNET_i2s (sender)); /* message with structure: * [TransportPongMessage][Transport name][Address] */ pong = GNUNET_malloc (sizeof (struct TransportPongMessage) + len_address + len_plugin); pong->header.size = htons (sizeof (struct TransportPongMessage) + len_address + len_plugin); pong->header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_PONG); pong->purpose.size = htonl (sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose) + sizeof (uint32_t) + sizeof (struct GNUNET_TIME_AbsoluteNBO) + len_address + len_plugin); pong->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_TRANSPORT_PONG_OWN); GNUNET_memcpy (&pong->challenge, &ping->challenge, sizeof (ping->challenge)); pong->addrlen = htonl (len_address + len_plugin); GNUNET_memcpy (&pong[1], addr, len_plugin); /* Copy transport plugin */ if (len_address > 0) { GNUNET_assert (NULL != addrend); GNUNET_memcpy (&((char *) &pong[1])[len_plugin], addrend, len_address); } if (GNUNET_TIME_absolute_get_remaining (*sig_cache_exp).rel_value_us < PONG_SIGNATURE_LIFETIME.rel_value_us / 4) { /* create / update cached sig */ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Creating PONG signature to indicate ownership.\n"); *sig_cache_exp = GNUNET_TIME_relative_to_absolute (PONG_SIGNATURE_LIFETIME); pong->expiration = GNUNET_TIME_absolute_hton (*sig_cache_exp); if (GNUNET_OK != GNUNET_CRYPTO_eddsa_sign (GST_my_private_key, &pong->purpose, sig_cache)) { GNUNET_log (GNUNET_ERROR_TYPE_ERROR, _("Failed to create PONG signature for peer `%s'\n"), GNUNET_i2s (sender)); } } else { pong->expiration = GNUNET_TIME_absolute_hton (*sig_cache_exp); } pong->signature = *sig_cache; GNUNET_assert (NULL != sender_address); /* first see if the session we got this PING from can be used to transmit * a response reliably */ if (NULL == papi) { ret = -1; } else { GNUNET_assert (NULL != papi->send); GNUNET_assert (NULL != papi->get_session); if (NULL == session) { session = papi->get_session (papi->cls, sender_address); } if (NULL == session) { GNUNET_break (0); ret = -1; } else { ret = papi->send (papi->cls, session, (const char *) pong, ntohs (pong->header.size), PONG_PRIORITY, ACCEPTABLE_PING_DELAY, NULL, NULL); if (-1 != ret) GST_neighbours_notify_data_sent (sender_address, session, pong->header.size); } } if (-1 != ret) { GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Transmitted PONG to `%s' via reliable mechanism\n", GNUNET_i2s (sender)); /* done! */ GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# PONGs unicast via reliable transport"), 1, GNUNET_NO); GNUNET_free (pong); return GNUNET_OK; } /* no reliable method found, try transmission via all known addresses */ GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# PONGs multicast to all available addresses"), 1, GNUNET_NO); GST_validation_get_addresses (sender, &multicast_pong, pong); GNUNET_free (pong); return GNUNET_OK; } /** * Validate an individual address. * * @param address address we should try to validate */ void GST_validation_handle_address (const struct GNUNET_HELLO_Address *address) { struct GNUNET_TRANSPORT_PluginFunctions *papi; struct ValidationEntry *ve; papi = GST_plugins_find (address->transport_name); if (NULL == papi) { /* This plugin is currently unvailable ... ignore */ GNUNET_log (GNUNET_ERROR_TYPE_INFO, "No plugin available for %s\n", address->transport_name); return; } ve = find_validation_entry (address); if (NULL == ve->revalidation_task) { GNUNET_log (GNUNET_ERROR_TYPE_INFO, "Validation process started for fresh address `%s' of %s\n", GST_plugins_a2s (ve->address), GNUNET_i2s (&ve->address->peer)); ve->revalidation_task = GNUNET_SCHEDULER_add_now (&revalidate_address, ve); } else { GNUNET_log (GNUNET_ERROR_TYPE_INFO, "Validation already running for address `%s' of %s\n", GST_plugins_a2s (ve->address), GNUNET_i2s (&ve->address->peer)); } } /** * Iterator callback to go over all addresses and try to validate them * (unless blocked or already validated). * * @param cls NULL * @param address the address * @param expiration expiration time * @return #GNUNET_OK (keep the address) */ static int validate_address_iterator (void *cls, const struct GNUNET_HELLO_Address *address, struct GNUNET_TIME_Absolute expiration) { if (0 == GNUNET_TIME_absolute_get_remaining (expiration).rel_value_us) { GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Skipping expired address from HELLO\n"); return GNUNET_OK; /* expired */ } GST_validation_handle_address (address); return GNUNET_OK; } /** * Add the validated peer address to the HELLO. * * @param cls the `struct ValidationEntry *` with the validated address * @param max space in @a buf * @param buf where to add the address * @return number of bytes written, #GNUNET_SYSERR to signal the * end of the iteration. */ static ssize_t add_valid_peer_address (void *cls, size_t max, void *buf) { struct ValidationEntry *ve = cls; if (GNUNET_YES == ve->copied) return GNUNET_SYSERR; /* Done */ ve->copied = GNUNET_YES; return GNUNET_HELLO_add_address (ve->address, ve->valid_until, buf, max); } /** * We've received a PONG. Check if it matches a pending PING and * mark the respective address as confirmed. * * @param sender peer sending the PONG * @param hdr the PONG * @return #GNUNET_OK if the message was fine, #GNUNET_SYSERR on serious error */ int GST_validation_handle_pong (const struct GNUNET_PeerIdentity *sender, const struct GNUNET_MessageHeader *hdr) { const struct TransportPongMessage *pong; struct ValidationEntry *ve; const char *tname; const char *addr; size_t addrlen; size_t slen; size_t size; struct GNUNET_HELLO_Message *hello; struct GNUNET_HELLO_Address address; int sig_res; int do_verify; if (0 == memcmp (&GST_my_identity, sender, sizeof (struct GNUNET_PeerIdentity))) return GNUNET_OK; /* our own, ignore! */ if (ntohs (hdr->size) < sizeof (struct TransportPongMessage)) { GNUNET_break_op (0); return GNUNET_SYSERR; } GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# PONG messages received"), 1, GNUNET_NO); /* message with structure: * [TransportPongMessage][Transport name][Address] */ pong = (const struct TransportPongMessage *) hdr; tname = (const char *) &pong[1]; size = ntohs (hdr->size) - sizeof (struct TransportPongMessage); addr = memchr (tname, '\0', size); if (NULL == addr) { GNUNET_break_op (0); return GNUNET_SYSERR; } addr++; slen = strlen (tname) + 1; addrlen = size - slen; if (NULL == GST_plugins_find (tname)) { /* we got the PONG, but the transport plugin specified in it is not supported by this peer, so this cannot be a good PONG for us. */ GNUNET_break_op (0); return GNUNET_OK; } address.peer = *sender; address.address = addr; address.address_length = addrlen; address.transport_name = tname; address.local_info = GNUNET_HELLO_ADDRESS_INFO_NONE; ve = find_validation_entry (&address); if ((NULL == ve) || (GNUNET_NO == ve->expecting_pong)) { GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# PONGs dropped, no matching pending validation"), 1, GNUNET_NO); return GNUNET_OK; } /* now check that PONG is well-formed */ if (0 != memcmp (&ve->address->peer, sender, sizeof (struct GNUNET_PeerIdentity))) { GNUNET_break_op (0); return GNUNET_SYSERR; } if (0 == GNUNET_TIME_absolute_get_remaining (GNUNET_TIME_absolute_ntoh (pong->expiration)).rel_value_us) { GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# PONGs dropped, signature expired"), 1, GNUNET_NO); return GNUNET_SYSERR; } sig_res = GNUNET_SYSERR; do_verify = GNUNET_YES; if (0 != GNUNET_TIME_absolute_get_remaining (ve->pong_sig_valid_until).rel_value_us) { /* We have a cached and valid signature for this peer, * try to compare instead of verify */ if (0 == memcmp (&ve->pong_sig_cache, &pong->signature, sizeof (struct GNUNET_CRYPTO_EddsaSignature))) { /* signatures are identical, we can skip verification */ sig_res = GNUNET_OK; do_verify = GNUNET_NO; } else { sig_res = GNUNET_SYSERR; /* signatures do not match, we have to verify */ } } if (GNUNET_YES == do_verify) { /* Do expensive verification */ sig_res = GNUNET_CRYPTO_eddsa_verify (GNUNET_SIGNATURE_PURPOSE_TRANSPORT_PONG_OWN, &pong->purpose, &pong->signature, &ve->address->peer.public_key); if (sig_res == GNUNET_SYSERR) { GNUNET_break_op (0); GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "Failed to verify: invalid signature on address `%s':%s from peer `%s'\n", tname, GST_plugins_a2s (ve->address), GNUNET_i2s (sender)); } } if (sig_res == GNUNET_SYSERR) { GNUNET_break_op (0); return GNUNET_SYSERR; } GNUNET_log (GNUNET_ERROR_TYPE_INFO, "Validation process successful for peer `%s' with plugin `%s' address `%s'\n", GNUNET_i2s (sender), tname, GST_plugins_a2s (ve->address)); GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# validations succeeded"), 1, GNUNET_NO); /* validity achieved, remember it! */ ve->expecting_pong = GNUNET_NO; ve->valid_until = GNUNET_TIME_relative_to_absolute (HELLO_ADDRESS_EXPIRATION); ve->pong_sig_cache = pong->signature; ve->pong_sig_valid_until = GNUNET_TIME_absolute_ntoh (pong->expiration); ve->latency = GNUNET_TIME_absolute_get_duration (ve->send_time); { if (GNUNET_YES == ve->known_to_ats) { GNUNET_assert (GNUNET_YES == GST_ats_is_known_no_session (ve->address)); GST_ats_update_delay (ve->address, GNUNET_TIME_relative_divide (ve->latency, 2)); } else { struct GNUNET_ATS_Properties prop; memset (&prop, 0, sizeof (prop)); GNUNET_break (GNUNET_ATS_NET_UNSPECIFIED != ve->network); prop.scope = ve->network; prop.delay = GNUNET_TIME_relative_divide (ve->latency, 2); GNUNET_assert (GNUNET_NO == GST_ats_is_known_no_session (ve->address)); ve->known_to_ats = GNUNET_YES; GST_ats_add_address (ve->address, &prop); GNUNET_assert (GNUNET_YES == GST_ats_is_known_no_session (ve->address)); } } if (validations_running > 0) { validations_running--; GNUNET_STATISTICS_set (GST_stats, gettext_noop ("# validations running"), validations_running, GNUNET_NO); GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Validation finished, %u validation processes running\n", validations_running); } else { GNUNET_break (0); } /* Notify about new validity */ validation_entry_changed (ve, GNUNET_TRANSPORT_VS_UPDATE); /* build HELLO to store in PEERINFO */ GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# HELLOs given to peerinfo"), 1, GNUNET_NO); ve->copied = GNUNET_NO; hello = GNUNET_HELLO_create (&ve->address->peer.public_key, &add_valid_peer_address, ve, GNUNET_NO); GNUNET_break (NULL != GNUNET_PEERINFO_add_peer (GST_peerinfo, hello, NULL, NULL)); GNUNET_free (hello); return GNUNET_OK; } /** * We've received a HELLO, check which addresses are new and trigger * validation. * * @param hello the HELLO we received * @return #GNUNET_OK if the message was fine, #GNUNET_SYSERR on serious error */ int GST_validation_handle_hello (const struct GNUNET_MessageHeader *hello) { const struct GNUNET_HELLO_Message *hm = (const struct GNUNET_HELLO_Message *) hello; struct GNUNET_PeerIdentity pid; int friend; friend = GNUNET_HELLO_is_friend_only (hm); if ( ( (GNUNET_YES != friend) && (GNUNET_NO != friend) ) || (GNUNET_OK != GNUNET_HELLO_get_id (hm, &pid)) ) { /* malformed HELLO */ GNUNET_break_op (0); return GNUNET_SYSERR; } if (0 == memcmp (&GST_my_identity, &pid, sizeof (struct GNUNET_PeerIdentity))) { /* got our own HELLO, how boring */ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Validation received our own HELLO (%s), ignoring\n", GNUNET_i2s (&pid)); return GNUNET_OK; } GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Validation received HELLO message for peer `%s' with size %u, checking for new addresses\n", GNUNET_i2s (&pid), ntohs (hello->size)); GNUNET_assert (NULL == GNUNET_HELLO_iterate_addresses (hm, GNUNET_NO, &validate_address_iterator, NULL)); return GNUNET_OK; } /** * Closure for #iterate_addresses(). */ struct IteratorContext { /** * Function to call on each address. */ GST_ValidationAddressCallback cb; /** * Closure for @e cb. */ void *cb_cls; }; /** * Call the callback in the closure for each validation entry. * * @param cls the `struct IteratorContext` * @param key the peer's identity * @param value the `struct ValidationEntry` * @return #GNUNET_OK (continue to iterate) */ static int iterate_addresses (void *cls, const struct GNUNET_PeerIdentity *key, void *value) { struct IteratorContext *ic = cls; struct ValidationEntry *ve = value; ic->cb (ic->cb_cls, ve->valid_until, ve->revalidation_block, ve->address); return GNUNET_OK; } /** * Call the given function for each address for the given target. * Can either give a snapshot (synchronous API) or be continuous. * * @param target peer information is requested for * @param cb function to call; will not be called after this function returns * @param cb_cls closure for @a cb */ void GST_validation_get_addresses (const struct GNUNET_PeerIdentity *target, GST_ValidationAddressCallback cb, void *cb_cls) { struct IteratorContext ic; ic.cb = cb; ic.cb_cls = cb_cls; GNUNET_CONTAINER_multipeermap_get_multiple (validation_map, target, &iterate_addresses, &ic); } /** * Update if we are using an address for a connection actively right now. * Based on this, the validation module will measure latency for the * address more or less often. * * @param address the address that we are now using (or not) * @param in_use #GNUNET_YES if we are now using the address for a connection, * #GNUNET_NO if we are no longer using the address for a connection */ void GST_validation_set_address_use (const struct GNUNET_HELLO_Address *address, int in_use) { struct ValidationEntry *ve; if (GNUNET_HELLO_address_check_option (address, GNUNET_HELLO_ADDRESS_INFO_INBOUND)) return; /* ignore inbound for validation */ if (NULL == GST_plugins_find (address->transport_name)) { /* How can we use an address for which we don't have the plugin? */ GNUNET_break (0); return; } ve = find_validation_entry (address); if (NULL == ve) { GNUNET_break (0); return; } if (in_use == ve->in_use) return; ve->in_use = in_use; if (GNUNET_YES == in_use) { /* from now on, higher frequeny, so reschedule now */ if (NULL != ve->revalidation_task) GNUNET_SCHEDULER_cancel (ve->revalidation_task); ve->revalidation_task = GNUNET_SCHEDULER_add_now (&revalidate_address, ve); } } /* end of file gnunet-service-transport_validation.c */