/* This file is part of GNUnet. (C) 2010,2011 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 transport/gnunet-service-transport_validation.c * @brief address validation subsystem * @author Christian Grothoff */ #include "platform.h" #include "gnunet-service-transport_validation.h" #include "gnunet-service-transport_plugins.h" #include "gnunet-service-transport_hello.h" #include "gnunet-service-transport_blacklist.h" #include "gnunet-service-transport.h" #include "gnunet_hello_lib.h" #include "gnunet_ats_service.h" #include "gnunet_peerinfo_service.h" #include "gnunet_signatures.h" /** * How long is a PONG signature valid? We'll recycle a signature until * 1/4 of this time is remaining. PONGs should expire so that if our * external addresses change an adversary cannot replay them indefinitely. * OTOH, we don't want to spend too much time generating PONG signatures, * so they must have some lifetime to reduce our CPU usage. */ #define PONG_SIGNATURE_LIFETIME GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_HOURS, 1) /** * After how long do we expire an address in a HELLO that we just * validated? This value is also used for our own addresses when we * create a HELLO. */ #define HELLO_ADDRESS_EXPIRATION GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_HOURS, 12) /** * How often do we allow PINGing an address that we have not yet * validated? This also determines how long we track an address that * we cannot validate (because after this time we can destroy the * validation record). */ #define UNVALIDATED_PING_KEEPALIVE GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 5) /** * How often do we PING an address that we have successfully validated * in the past but are not actively using? Should be (significantly) * smaller than HELLO_ADDRESS_EXPIRATION. */ #define VALIDATED_PING_FREQUENCY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 15) /** * How often do we PING an address that we are currently using? */ #define CONNECTED_PING_FREQUENCY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 2) /** * How much delay is acceptable for sending the PING or PONG? */ #define ACCEPTABLE_PING_DELAY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 1) /** * Size of the validation map hashmap. */ #define VALIDATION_MAP_SIZE 256 /** * Priority to use for PINGs */ #define PING_PRIORITY 2 /** * Priority to use for PONGs */ #define PONG_PRIORITY 4 GNUNET_NETWORK_STRUCT_BEGIN /** * Message used to ask a peer to validate receipt (to check an address * from a HELLO). Followed by the address we are trying to validate, * or an empty address if we are just sending a PING to confirm that a * connection which the receiver (of the PING) initiated is still valid. */ struct TransportPingMessage { /** * Type will be GNUNET_MESSAGE_TYPE_TRANSPORT_PING */ struct GNUNET_MessageHeader header; /** * Challenge code (to ensure fresh reply). */ uint32_t challenge GNUNET_PACKED; /** * Who is the intended recipient? */ struct GNUNET_PeerIdentity target; }; /** * Message used to validate a HELLO. The challenge is included in the * confirmation to make matching of replies to requests possible. The * signature signs our public key, an expiration time and our address.

* * 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_RsaSignature signature; /** * GNUNET_SIGNATURE_PURPOSE_TRANSPORT_PONG_OWN to confirm that this is a * plausible address for the signing peer. */ struct GNUNET_CRYPTO_RsaSignaturePurpose 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; /** * Public key of the peer. */ struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded public_key; /** * The identity of the peer. FIXME: duplicated (also in 'address') */ struct GNUNET_PeerIdentity pid; /** * ID of task that will clean up this entry if nothing happens. */ GNUNET_SCHEDULER_TaskIdentifier timeout_task; /** * ID of task that will trigger address revalidation. */ GNUNET_SCHEDULER_TaskIdentifier revalidation_task; /** * At what time did we send the latest validation request (PING)? */ struct GNUNET_TIME_Absolute send_time; /** * Until when is this address valid? * ZERO if it is not currently considered valid. */ struct GNUNET_TIME_Absolute 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; /** * 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; /* FIXME: DEBUGGING */ int last_line_set_to_no; int last_line_set_to_yes; }; /** * Context of currently active requests to peerinfo * for validation of HELLOs. */ struct CheckHelloValidatedContext { /** * This is a doubly-linked list. */ struct CheckHelloValidatedContext *next; /** * This is a doubly-linked list. */ struct CheckHelloValidatedContext *prev; /** * Hello that we are validating. */ const struct GNUNET_HELLO_Message *hello; }; /** * Head of linked list of HELLOs awaiting validation. */ static struct CheckHelloValidatedContext *chvc_head; /** * Tail of linked list of HELLOs awaiting validation */ static struct CheckHelloValidatedContext *chvc_tail; /** * 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_MultiHashMap *validation_map; /** * Context for peerinfo iteration. */ static struct GNUNET_PEERINFO_NotifyContext *pnc; /** * 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; }; /** * 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 GNUNET_HashCode * 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; } /** * 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 GNUNET_HashCode * key, void *value) { struct ValidationEntry *ve = value; if (NULL != ve->bc) { GST_blacklist_test_cancel (ve->bc); ve->bc = NULL; } GNUNET_break (GNUNET_OK == GNUNET_CONTAINER_multihashmap_remove (validation_map, &ve->pid.hashPubKey, ve)); GNUNET_HELLO_address_free (ve->address); if (GNUNET_SCHEDULER_NO_TASK != ve->timeout_task) { GNUNET_SCHEDULER_cancel (ve->timeout_task); ve->timeout_task = GNUNET_SCHEDULER_NO_TASK; } if (GNUNET_SCHEDULER_NO_TASK != ve->revalidation_task) { GNUNET_SCHEDULER_cancel (ve->revalidation_task); ve->revalidation_task = GNUNET_SCHEDULER_NO_TASK; } 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' * @param tc scheduler context (unused) */ static void timeout_hello_validation (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct ValidationEntry *ve = cls; struct GNUNET_TIME_Absolute max; struct GNUNET_TIME_Relative left; ve->timeout_task = GNUNET_SCHEDULER_NO_TASK; max = GNUNET_TIME_absolute_max (ve->valid_until, ve->revalidation_block); left = GNUNET_TIME_absolute_get_remaining (max); if (left.rel_value > 0) { /* should wait a bit longer */ ve->timeout_task = GNUNET_SCHEDULER_add_delayed (left, &timeout_hello_validation, ve); return; } GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# address records discarded"), 1, GNUNET_NO); cleanup_validation_entry (NULL, &ve->pid.hashPubKey, 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 result GNUNET_OK if the connection is allowed, GNUNET_NO if not */ static void transmit_ping_if_allowed (void *cls, const struct GNUNET_PeerIdentity *pid, int result) { struct ValidationEntry *ve = cls; struct TransportPingMessage ping; struct GNUNET_TRANSPORT_PluginFunctions *papi; const struct GNUNET_MessageHeader *hello; ssize_t ret; size_t tsize; size_t slen; uint16_t hsize; ve->bc = NULL; GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Transmitting plain PING to `%s' %s\n", GNUNET_i2s (pid), GST_plugins_a2s (ve->address)); slen = strlen (ve->address->transport_name) + 1; hello = GST_hello_get (); 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_SERVER_MAX_MESSAGE_SIZE) { GNUNET_log (GNUNET_ERROR_TYPE_ERROR, _ ("Not transmitting `%s' with `%s', message too big (%u bytes!). This should not happen.\n"), "HELLO", "PING", (unsigned int) tsize); /* message too big (!?), get rid of HELLO */ hsize = 0; tsize = sizeof (struct TransportPingMessage) + ve->address->address_length + slen + hsize; } { char message_buf[tsize]; /* build message with structure: * [HELLO][TransportPingMessage][Transport name][Address] */ memcpy (message_buf, hello, hsize); memcpy (&message_buf[hsize], &ping, sizeof (struct TransportPingMessage)); memcpy (&message_buf[sizeof (struct TransportPingMessage) + hsize], ve->address->transport_name, slen); memcpy (&message_buf[sizeof (struct TransportPingMessage) + slen + hsize], ve->address, ve->address->address_length); papi = GST_plugins_find (ve->address->transport_name); if (papi == NULL) ret = -1; else { GNUNET_assert (papi->send != NULL); GNUNET_assert (papi->get_session != NULL); struct Session * session = papi->get_session(papi->cls, ve->address); if (session != NULL) { ret = papi->send (papi->cls, session, message_buf, tsize, PING_PRIORITY, ACCEPTABLE_PING_DELAY, NULL, NULL); } else { /* Could not get a valid session */ GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Could not get a valid session for `%s' %s\n", GNUNET_i2s (pid), GST_plugins_a2s (ve->address)); ret = -1; } } } if (-1 != ret) { ve->send_time = GNUNET_TIME_absolute_get (); GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# PING without HELLO messages sent"), 1, GNUNET_NO); ve->expecting_pong = GNUNET_YES; } } /** * Do address validation again to keep address valid. * * @param cls the 'struct ValidationEntry' * @param tc scheduler context (unused) */ static void revalidate_address (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct ValidationEntry *ve = cls; struct GNUNET_TIME_Relative canonical_delay; struct GNUNET_TIME_Relative delay; struct GST_BlacklistCheck *bc; uint32_t rdelay; ve->revalidation_task = GNUNET_SCHEDULER_NO_TASK; delay = GNUNET_TIME_absolute_get_remaining (ve->revalidation_block); /* How long until we can possibly permit the next PING? */ canonical_delay = (ve->in_use == GNUNET_YES) ? CONNECTED_PING_FREQUENCY : ((GNUNET_TIME_absolute_get_remaining (ve->valid_until).rel_value > 0) ? VALIDATED_PING_FREQUENCY : UNVALIDATED_PING_KEEPALIVE); if (delay.rel_value > canonical_delay.rel_value * 2) { /* situation changed, recalculate delay */ delay = canonical_delay; ve->revalidation_block = GNUNET_TIME_relative_to_absolute (delay); } if (delay.rel_value > 0) { /* should wait a bit longer */ ve->revalidation_task = GNUNET_SCHEDULER_add_delayed (delay, &revalidate_address, ve); return; } 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); delay = GNUNET_TIME_relative_add (canonical_delay, GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, rdelay)); ve->revalidation_task = GNUNET_SCHEDULER_add_delayed (delay, &revalidate_address, ve); /* start PINGing by checking blacklist */ GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# address revalidations started"), 1, GNUNET_NO); bc = GST_blacklist_test_allowed (&ve->pid, ve->address->transport_name, &transmit_ping_if_allowed, ve); if (NULL != bc) ve->bc = bc; /* only set 'bc' if 'transmit_ping_if_allowed' was not already * called... */ } /** * 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 public_key public key of the peer, NULL for unknown * @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_CRYPTO_RsaPublicKeyBinaryEncoded *public_key, const struct GNUNET_HELLO_Address *address) { struct ValidationEntryMatchContext vemc; struct ValidationEntry *ve; vemc.ve = NULL; vemc.address = address; GNUNET_CONTAINER_multihashmap_get_multiple (validation_map, &address->peer.hashPubKey, &validation_entry_match, &vemc); if (NULL != (ve = vemc.ve)) return ve; if (public_key == NULL) return NULL; ve = GNUNET_malloc (sizeof (struct ValidationEntry)); ve->in_use = GNUNET_SYSERR; /* not defined */ ve->last_line_set_to_no = 0; ve->last_line_set_to_yes = 0; ve->address = GNUNET_HELLO_address_copy (address); ve->public_key = *public_key; ve->pid = address->peer; 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_multihashmap_put (validation_map, &address->peer.hashPubKey, ve, GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE); ve->expecting_pong = GNUNET_NO; 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) */ 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_CRYPTO_RsaPublicKeyBinaryEncoded public_key; if (GNUNET_TIME_absolute_get_remaining (expiration).rel_value == 0) return GNUNET_OK; /* expired */ if ((GNUNET_OK != GNUNET_HELLO_get_id (hello, &pid)) || (GNUNET_OK != GNUNET_HELLO_get_key (hello, &public_key))) { GNUNET_break (0); return GNUNET_OK; /* invalid HELLO !? */ } if (0 == memcmp (&GST_my_identity, &pid, sizeof (struct GNUNET_PeerIdentity))) { /* Peerinfo returned own identity, skip validation */ return GNUNET_OK; } ve = find_validation_entry (&public_key, address); ve->valid_until = GNUNET_TIME_absolute_max (ve->valid_until, expiration); if (GNUNET_SCHEDULER_NO_TASK == ve->revalidation_task) ve->revalidation_task = GNUNET_SCHEDULER_add_now (&revalidate_address, ve); GNUNET_ATS_address_update (GST_ats, address, NULL, NULL, 0); return GNUNET_OK; } /** * Function called for any HELLO known to PEERINFO. * * @param cls unused * @param peer id of the peer, NULL for last call * @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; GNUNET_assert (NULL == GNUNET_HELLO_iterate_addresses (hello, GNUNET_NO, &add_valid_address, (void *) hello)); } /** * Start the validation subsystem. */ void GST_validation_start () { validation_map = GNUNET_CONTAINER_multihashmap_create (VALIDATION_MAP_SIZE); pnc = GNUNET_PEERINFO_notify (GST_cfg, &process_peerinfo_hello, NULL); } /** * Stop the validation subsystem. */ void GST_validation_stop () { struct CheckHelloValidatedContext *chvc; GNUNET_CONTAINER_multihashmap_iterate (validation_map, &cleanup_validation_entry, NULL); GNUNET_CONTAINER_multihashmap_destroy (validation_map); validation_map = NULL; while (NULL != (chvc = chvc_head)) { GNUNET_CONTAINER_DLL_remove (chvc_head, chvc_tail, chvc); GNUNET_free (chvc); } GNUNET_PEERINFO_notify_cancel (pnc); } /** * Send the given PONG to the given address. * * @param cls the PONG message * @param public_key public key for the peer, never NULL * @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, const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded *public_key, 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; papi = GST_plugins_find (address->transport_name); if (papi == NULL) return; GNUNET_assert (papi->send != NULL); GNUNET_assert (papi->get_session != NULL); struct Session * session = papi->get_session(papi->cls, address); if (session == NULL) { GNUNET_break (0); return; } papi->send (papi->cls, session, (const char *) pong, ntohs (pong->header.size), PONG_PRIORITY, ACCEPTABLE_PING_DELAY, NULL, NULL); } /** * 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 */ void GST_validation_handle_ping (const struct GNUNET_PeerIdentity *sender, const struct GNUNET_MessageHeader *hdr, const struct GNUNET_HELLO_Address *sender_address, struct Session *session) { const struct TransportPingMessage *ping; struct TransportPongMessage *pong; struct GNUNET_TRANSPORT_PluginFunctions *papi; struct GNUNET_CRYPTO_RsaSignature *sig_cache; struct GNUNET_TIME_Absolute *sig_cache_exp; const char *addr; const char *addrend; size_t alen; size_t slen; ssize_t ret; struct GNUNET_HELLO_Address address; if (ntohs (hdr->size) < sizeof (struct TransportPingMessage)) { GNUNET_break_op (0); return; } 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_STATISTICS_update (GST_stats, gettext_noop ("# PING messages received"), 1, GNUNET_NO); addr = (const char *) &ping[1]; alen = 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; if (0 < alen) { addrend = memchr (addr, '\0', alen); if (NULL == addrend) { GNUNET_break_op (0); return; } addrend++; slen = strlen (addr) + 1; alen -= slen; address.address = addrend; address.address_length = alen; address.transport_name = addr; address.peer = *sender; if (GNUNET_YES != GST_hello_test_address (&address, &sig_cache, &sig_cache_exp)) { GNUNET_log (GNUNET_ERROR_TYPE_INFO, _ ("Not confirming PING with address `%s' since I cannot confirm having this address.\n"), GST_plugins_a2s (&address)); return; } } else { addrend = NULL; /* make gcc happy */ slen = 0; static struct GNUNET_CRYPTO_RsaSignature no_address_signature; static struct GNUNET_TIME_Absolute no_address_signature_expiration; sig_cache = &no_address_signature; sig_cache_exp = &no_address_signature_expiration; } pong = GNUNET_malloc (sizeof (struct TransportPongMessage) + alen + slen); pong->header.size = htons (sizeof (struct TransportPongMessage) + alen + slen); pong->header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_PONG); pong->purpose.size = htonl (sizeof (struct GNUNET_CRYPTO_RsaSignaturePurpose) + sizeof (uint32_t) + sizeof (struct GNUNET_TIME_AbsoluteNBO) + alen + slen); pong->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_TRANSPORT_PONG_OWN); pong->challenge = ping->challenge; pong->addrlen = htonl (alen + slen); memcpy (&pong[1], addr, slen); memcpy (&((char *) &pong[1])[slen], addrend, alen); if (GNUNET_TIME_absolute_get_remaining (*sig_cache_exp).rel_value < PONG_SIGNATURE_LIFETIME.rel_value / 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); GNUNET_assert (GNUNET_OK == GNUNET_CRYPTO_rsa_sign (GST_my_private_key, &pong->purpose, sig_cache)); } else { pong->expiration = GNUNET_TIME_absolute_hton (*sig_cache_exp); } pong->signature = *sig_cache; GNUNET_assert (sender_address != NULL); /* first see if the session we got this PING from can be used to transmit * a response reliably */ papi = GST_plugins_find (sender_address->transport_name); if (papi == NULL) ret = -1; else { GNUNET_assert (papi->send != NULL); GNUNET_assert (papi->get_session != NULL); if (session == NULL) { session = papi->get_session (papi->cls, sender_address); } if (session == NULL) { 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 (ret != -1) { 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; } /* 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); } /** * Context for the 'validate_address' function */ struct ValidateAddressContext { /** * Hash of the public key of the peer whose address is being validated. */ struct GNUNET_PeerIdentity pid; /** * Public key of the peer whose address is being validated. */ struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded public_key; }; /** * Iterator callback to go over all addresses and try to validate them * (unless blocked or already validated). * * @param cls pointer to a 'struct ValidateAddressContext' * @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) { const struct ValidateAddressContext *vac = cls; struct ValidationEntry *ve; if (GNUNET_TIME_absolute_get_remaining (expiration).rel_value == 0) return GNUNET_OK; /* expired */ ve = find_validation_entry (&vac->public_key, address); if (GNUNET_SCHEDULER_NO_TASK == ve->revalidation_task) ve->revalidation_task = GNUNET_SCHEDULER_add_now (&revalidate_address, ve); return GNUNET_OK; } /** * Add the validated peer address to the HELLO. * * @param cls the 'struct ValidationEntry' with the validated address * @param max space in buf * @param buf where to add the address * @return number of bytes written, 0 to signal the * end of the iteration. */ static size_t add_valid_peer_address (void *cls, size_t max, void *buf) { struct ValidationEntry *ve = cls; if (GNUNET_YES == ve->copied) return 0; /* terminate */ 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 */ void 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; if (ntohs (hdr->size) < sizeof (struct TransportPongMessage)) { GNUNET_break_op (0); return; } GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# PONG messages received"), 1, GNUNET_NO); 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; } addr++; slen = strlen (tname) + 1; addrlen = size - slen; address.peer = *sender; address.address = addr; address.address_length = addrlen; address.transport_name = tname; ve = find_validation_entry (NULL, &address); if ((NULL == ve) || (ve->expecting_pong == GNUNET_NO)) { GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# PONGs dropped, no matching pending validation"), 1, GNUNET_NO); return; } /* now check that PONG is well-formed */ if (0 != memcmp (&ve->pid, sender, sizeof (struct GNUNET_PeerIdentity))) { GNUNET_break_op (0); return; } if (GNUNET_OK != GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_TRANSPORT_PONG_OWN, &pong->purpose, &pong->signature, &ve->public_key)) { GNUNET_break_op (0); return; } if (GNUNET_TIME_absolute_get_remaining (GNUNET_TIME_absolute_ntoh (pong->expiration)).rel_value == 0) { GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# PONGs dropped, signature expired"), 1, GNUNET_NO); return; } GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Address validated for peer `%s' with plugin `%s': `%s'\n", GNUNET_i2s (sender), tname, GST_plugins_a2s (ve->address)); /* validity achieved, remember it! */ ve->expecting_pong = GNUNET_NO; ve->valid_until = GNUNET_TIME_relative_to_absolute (HELLO_ADDRESS_EXPIRATION); ve->latency = GNUNET_TIME_absolute_get_duration (ve->send_time); { struct GNUNET_ATS_Information ats; ats.type = htonl (GNUNET_ATS_QUALITY_NET_DELAY); ats.value = htonl ((uint32_t) ve->latency.rel_value); GNUNET_ATS_address_update (GST_ats, ve->address, NULL, &ats, 1); } /* build HELLO to store in PEERINFO */ ve->copied = GNUNET_NO; hello = GNUNET_HELLO_create (&ve->public_key, &add_valid_peer_address, ve); GNUNET_PEERINFO_add_peer (GST_peerinfo, hello, NULL, NULL); GNUNET_free (hello); } /** * We've received a HELLO, check which addresses are new and trigger * validation. * * @param hello the HELLO we received */ void GST_validation_handle_hello (const struct GNUNET_MessageHeader *hello) { const struct GNUNET_HELLO_Message *hm = (const struct GNUNET_HELLO_Message *) hello; struct ValidateAddressContext vac; struct GNUNET_HELLO_Message *h; if ((GNUNET_OK != GNUNET_HELLO_get_id (hm, &vac.pid)) || (GNUNET_OK != GNUNET_HELLO_get_key (hm, &vac.public_key))) { /* malformed HELLO */ GNUNET_break (0); return; } if (0 == memcmp (&GST_my_identity, &vac.pid, sizeof (struct GNUNET_PeerIdentity))) return; /* Add peer identity without addresses to peerinfo service */ h = GNUNET_HELLO_create (&vac.public_key, NULL, NULL); GNUNET_PEERINFO_add_peer (GST_peerinfo, h, NULL, NULL); #if VERBOSE_VALIDATION GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, _("Adding `%s' without addresses for peer `%s'\n"), "HELLO", GNUNET_i2s (&vac.pid)); #endif GNUNET_free (h); GNUNET_assert (NULL == GNUNET_HELLO_iterate_addresses (hm, GNUNET_NO, &validate_address_iterator, &vac)); } /** * Closure for 'iterate_addresses' */ struct IteratorContext { /** * Function to call on each address. */ GST_ValidationAddressCallback cb; /** * Closure for 'cb'. */ void *cb_cls; }; /** * Call the callback in the closure for each validation entry. * * @param cls the 'struct GST_ValidationIteratorContext' * @param key the peer's identity * @param value the 'struct ValidationEntry' * @return GNUNET_OK (continue to iterate) */ static int iterate_addresses (void *cls, const GNUNET_HashCode * key, void *value) { struct IteratorContext *ic = cls; struct ValidationEntry *ve = value; ic->cb (ic->cb_cls, &ve->public_key, 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 '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_multihashmap_get_multiple (validation_map, &target->hashPubKey, &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 * @param session the session * @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 * @param line line of caller just for DEBUGGING! */ void GST_validation_set_address_use (const struct GNUNET_HELLO_Address *address, struct Session *session, int in_use, int line) { struct ValidationEntry *ve; if (NULL != address) ve = find_validation_entry (NULL, address); else ve = NULL; /* FIXME: lookup based on session... */ if (NULL == ve) { /* this can happen for inbound connections (sender_address_len == 0); */ return; } if (ve->in_use == in_use) { if (GNUNET_YES == in_use) { GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Error setting address in use for peer `%s' `%s' to USED: set last time by %i, called now by %i\n", GNUNET_i2s (&address->peer), GST_plugins_a2s (address), ve->last_line_set_to_yes, line); } if (GNUNET_NO == in_use) { GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Error setting address in use for peer `%s' `%s' to NOT_USED: set last time by %i, called now by %i\n", GNUNET_i2s (&address->peer), GST_plugins_a2s (address), ve->last_line_set_to_no, line); } } if (GNUNET_YES == in_use) { ve->last_line_set_to_yes = line; } if (GNUNET_NO == in_use) { ve->last_line_set_to_no = line; } GNUNET_break (ve->in_use != in_use); /* should be different... */ ve->in_use = in_use; if (in_use == GNUNET_YES) { /* from now on, higher frequeny, so reschedule now */ GNUNET_SCHEDULER_cancel (ve->revalidation_task); ve->revalidation_task = GNUNET_SCHEDULER_add_now (&revalidate_address, ve); } } /** * Query validation about the latest observed latency on a given * address. * * @param sender peer * @param address the address * @param session session * @return observed latency of the address, FOREVER if the address was * never successfully validated */ struct GNUNET_TIME_Relative GST_validation_get_address_latency (const struct GNUNET_PeerIdentity *sender, const struct GNUNET_HELLO_Address *address, struct Session *session) { struct ValidationEntry *ve; if (NULL == address) { GNUNET_break (0); // FIXME: support having latency only with session... return GNUNET_TIME_UNIT_FOREVER_REL; } ve = find_validation_entry (NULL, address); if (NULL == ve) return GNUNET_TIME_UNIT_FOREVER_REL; return ve->latency; } /* end of file gnunet-service-transport_validation.c */