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- /*
- This file is part of GNUnet.
- Copyright (C) 2011-2018 GNUnet e.V.
- GNUnet is free software: you can redistribute it and/or modify it
- under the terms of the GNU Affero General Public License as published
- by the Free Software Foundation, either version 3 of the License,
- 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
- Affero General Public License for more details.
- You should have received a copy of the GNU Affero General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>.
- SPDX-License-Identifier: AGPL3.0-or-later
- */
- /**
- * @file gns/gnunet-service-gns.c
- * @brief GNU Name System (main service)
- * @author Martin Schanzenbach
- * @author Christian Grothoff
- */
- #include "platform.h"
- #include "gnunet_util_lib.h"
- #include "gnunet_dns_service.h"
- #include "gnunet_dnsparser_lib.h"
- #include "gnunet_dht_service.h"
- #include "gnunet_namecache_service.h"
- #include "gnunet_gnsrecord_lib.h"
- #include "gnunet_gns_service.h"
- #include "gnunet_statistics_service.h"
- #include "gns.h"
- #include "gnunet-service-gns_resolver.h"
- #include "gnunet-service-gns_interceptor.h"
- #include "gnunet_protocols.h"
- /**
- * GnsClient prototype
- */
- struct GnsClient;
- /**
- * Handle to a lookup operation from client via API.
- */
- struct ClientLookupHandle
- {
- /**
- * We keep these in a DLL.
- */
- struct ClientLookupHandle *next;
- /**
- * We keep these in a DLL.
- */
- struct ClientLookupHandle *prev;
- /**
- * Client handle
- */
- struct GnsClient *gc;
- /**
- * Active handle for the lookup.
- */
- struct GNS_ResolverHandle *lookup;
- /**
- * request id
- */
- uint32_t request_id;
- };
- /**
- * Information we track per connected client.
- */
- struct GnsClient
- {
- /**
- * The client
- */
- struct GNUNET_SERVICE_Client *client;
- /**
- * The MQ
- */
- struct GNUNET_MQ_Handle *mq;
- /**
- * Head of the DLL.
- */
- struct ClientLookupHandle *clh_head;
- /**
- * Tail of the DLL.
- */
- struct ClientLookupHandle *clh_tail;
- };
- /**
- * Representation of a TLD, mapping the respective TLD string
- * (i.e. ".gnu") to the respective public key of the zone.
- */
- struct GNS_TopLevelDomain
- {
- /**
- * Kept in a DLL, as there are unlikely enough of these to
- * warrant a hash map.
- */
- struct GNS_TopLevelDomain *next;
- /**
- * Kept in a DLL, as there are unlikely enough of these to
- * warrant a hash map.
- */
- struct GNS_TopLevelDomain *prev;
- /**
- * Public key associated with the @a tld.
- */
- struct GNUNET_CRYPTO_EcdsaPublicKey pkey;
- /**
- * Top-level domain as a string, including leading ".".
- */
- char *tld;
- };
- /**
- * Our handle to the DHT
- */
- static struct GNUNET_DHT_Handle *dht_handle;
- /**
- * Our handle to the namecache service
- */
- static struct GNUNET_NAMECACHE_Handle *namecache_handle;
- /**
- * #GNUNET_YES if ipv6 is supported
- */
- static int v6_enabled;
- /**
- * #GNUNET_YES if ipv4 is supported
- */
- static int v4_enabled;
- /**
- * Handle to the statistics service
- */
- static struct GNUNET_STATISTICS_Handle *statistics;
- /**
- * Head of DLL of TLDs we map to GNS zones.
- */
- static struct GNS_TopLevelDomain *tld_head;
- /**
- * Tail of DLL of TLDs we map to GNS zones.
- */
- static struct GNS_TopLevelDomain *tld_tail;
- /**
- * Find GNS zone belonging to TLD @a tld.
- *
- * @param tld_str top-level domain to look up
- * @param[out] pkey public key to set
- * @return #GNUNET_YES if @a tld was found #GNUNET_NO if not
- */
- int
- GNS_find_tld (const char *tld_str,
- struct GNUNET_CRYPTO_EcdsaPublicKey *pkey)
- {
- if ('\0' == *tld_str)
- return GNUNET_NO;
- for (struct GNS_TopLevelDomain *tld = tld_head;
- NULL != tld;
- tld = tld->next)
- {
- if (0 == strcasecmp (tld_str,
- tld->tld))
- {
- *pkey = tld->pkey;
- return GNUNET_YES;
- }
- }
- if (GNUNET_OK ==
- GNUNET_GNSRECORD_zkey_to_pkey (tld_str + 1,
- pkey))
- return GNUNET_YES; /* TLD string *was* the public key */
- return GNUNET_NO;
- }
- /**
- * Obtain the TLD of the given @a name.
- *
- * @param name a name
- * @return the part of @a name after the last ".",
- * or @a name if @a name does not contain a "."
- */
- const char *
- GNS_get_tld (const char *name)
- {
- const char *tld;
- tld = strrchr (name,
- (unsigned char) '.');
- if (NULL == tld)
- tld = name;
- else
- tld++; /* skip the '.' */
- return tld;
- }
- /**
- * Task run during shutdown.
- *
- * @param cls unused, NULL
- */
- static void
- shutdown_task (void *cls)
- {
- struct GNS_TopLevelDomain *tld;
- (void) cls;
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Shutting down!\n");
- GNS_interceptor_done ();
- GNS_resolver_done ();
- if (NULL != statistics)
- {
- GNUNET_STATISTICS_destroy (statistics,
- GNUNET_NO);
- statistics = NULL;
- }
- if (NULL != namecache_handle)
- {
- GNUNET_NAMECACHE_disconnect (namecache_handle);
- namecache_handle = NULL;
- }
- if (NULL != dht_handle)
- {
- GNUNET_DHT_disconnect (dht_handle);
- dht_handle = NULL;
- }
- while (NULL != (tld = tld_head))
- {
- GNUNET_CONTAINER_DLL_remove (tld_head,
- tld_tail,
- tld);
- GNUNET_free (tld->tld);
- GNUNET_free (tld);
- }
- }
- /**
- * Called whenever a client is disconnected.
- *
- * @param cls closure
- * @param client identification of the client
- * @param app_ctx @a client
- */
- static void
- client_disconnect_cb (void *cls,
- struct GNUNET_SERVICE_Client *client,
- void *app_ctx)
- {
- struct ClientLookupHandle *clh;
- struct GnsClient *gc = app_ctx;
- (void) cls;
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Client %p disconnected\n",
- client);
- while (NULL != (clh = gc->clh_head))
- {
- if (NULL != clh->lookup)
- GNS_resolver_lookup_cancel (clh->lookup);
- GNUNET_CONTAINER_DLL_remove (gc->clh_head,
- gc->clh_tail,
- clh);
- GNUNET_free (clh);
- }
- GNUNET_free (gc);
- }
- /**
- * Add a client to our list of active clients.
- *
- * @param cls NULL
- * @param client client to add
- * @param mq message queue for @a client
- * @return internal namestore client structure for this client
- */
- static void *
- client_connect_cb (void *cls,
- struct GNUNET_SERVICE_Client *client,
- struct GNUNET_MQ_Handle *mq)
- {
- struct GnsClient *gc;
- (void) cls;
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Client %p connected\n",
- client);
- gc = GNUNET_new (struct GnsClient);
- gc->client = client;
- gc->mq = mq;
- return gc;
- }
- /**
- * Reply to client with the result from our lookup.
- *
- * @param cls the closure (our client lookup handle)
- * @param rd_count the number of records in @a rd
- * @param rd the record data
- */
- static void
- send_lookup_response (void *cls,
- uint32_t rd_count,
- const struct GNUNET_GNSRECORD_Data *rd)
- {
- struct ClientLookupHandle *clh = cls;
- struct GnsClient *gc = clh->gc;
- struct GNUNET_MQ_Envelope *env;
- struct LookupResultMessage *rmsg;
- ssize_t len;
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Sending LOOKUP_RESULT message with %u results\n",
- (unsigned int) rd_count);
- len = GNUNET_GNSRECORD_records_get_size (rd_count,
- rd);
- if (len < 0)
- {
- GNUNET_break (0);
- GNUNET_SERVICE_client_drop (gc->client);
- return;
- }
- if (len > UINT16_MAX - sizeof(*rmsg))
- {
- GNUNET_break (0);
- GNUNET_SERVICE_client_drop (gc->client);
- return;
- }
- env = GNUNET_MQ_msg_extra (rmsg,
- len,
- GNUNET_MESSAGE_TYPE_GNS_LOOKUP_RESULT);
- rmsg->id = clh->request_id;
- rmsg->rd_count = htonl (rd_count);
- GNUNET_assert (len ==
- GNUNET_GNSRECORD_records_serialize (rd_count,
- rd,
- len,
- (char*) &rmsg[1]));
- GNUNET_MQ_send (GNUNET_SERVICE_client_get_mq (gc->client),
- env);
- GNUNET_CONTAINER_DLL_remove (gc->clh_head,
- gc->clh_tail,
- clh);
- GNUNET_free (clh);
- GNUNET_STATISTICS_update (statistics,
- "Completed lookups", 1,
- GNUNET_NO);
- GNUNET_STATISTICS_update (statistics,
- "Records resolved",
- rd_count,
- GNUNET_NO);
- }
- /**
- * Checks a #GNUNET_MESSAGE_TYPE_GNS_LOOKUP message
- *
- * @param cls client sending the message
- * @param l_msg message of type `struct LookupMessage`
- * @return #GNUNET_OK if @a l_msg is well-formed
- */
- static int
- check_lookup (void *cls,
- const struct LookupMessage *l_msg)
- {
- size_t nlen;
- (void) cls;
- GNUNET_MQ_check_zero_termination (l_msg);
- nlen = ntohs (l_msg->header.size) - sizeof(struct LookupMessage);
- if (nlen > GNUNET_DNSPARSER_MAX_NAME_LENGTH)
- {
- GNUNET_break (0);
- return GNUNET_SYSERR;
- }
- return GNUNET_OK;
- }
- /**
- * Handle lookup requests from client
- *
- * @param cls the closure
- * @param client the client
- * @param message the message
- */
- static void
- handle_lookup (void *cls,
- const struct LookupMessage *sh_msg)
- {
- struct GnsClient *gc = cls;
- char name[GNUNET_DNSPARSER_MAX_NAME_LENGTH + 1];
- struct ClientLookupHandle *clh;
- char *nameptr = name;
- const char *utf_in;
- GNUNET_SERVICE_client_continue (gc->client);
- utf_in = (const char *) &sh_msg[1];
- GNUNET_STRINGS_utf8_tolower (utf_in,
- nameptr);
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Received LOOKUP `%s' message\n",
- name);
- clh = GNUNET_new (struct ClientLookupHandle);
- GNUNET_CONTAINER_DLL_insert (gc->clh_head,
- gc->clh_tail,
- clh);
- clh->gc = gc;
- clh->request_id = sh_msg->id;
- if ((GNUNET_DNSPARSER_TYPE_A == ntohl (sh_msg->type)) &&
- (GNUNET_OK != v4_enabled))
- {
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "LOOKUP: Query for A record but AF_INET not supported!");
- send_lookup_response (clh,
- 0,
- NULL);
- return;
- }
- if ((GNUNET_DNSPARSER_TYPE_AAAA == ntohl (sh_msg->type)) &&
- (GNUNET_OK != v6_enabled))
- {
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "LOOKUP: Query for AAAA record but AF_INET6 not supported!");
- send_lookup_response (clh,
- 0,
- NULL);
- return;
- }
- clh->lookup = GNS_resolver_lookup (&sh_msg->zone,
- ntohl (sh_msg->type),
- name,
- (enum GNUNET_GNS_LocalOptions) ntohs (
- sh_msg->options),
- &send_lookup_response, clh);
- GNUNET_STATISTICS_update (statistics,
- "Lookup attempts",
- 1, GNUNET_NO);
- }
- /**
- * Reads the configuration and populates TLDs
- *
- * @param cls unused
- * @param section name of section in config, always "gns"
- * @param option name of the option, TLDs start with "."
- * @param value value for the option, public key for TLDs
- */
- static void
- read_service_conf (void *cls,
- const char *section,
- const char *option,
- const char *value)
- {
- struct GNUNET_CRYPTO_EcdsaPublicKey pk;
- struct GNS_TopLevelDomain *tld;
- (void) cls;
- (void) section;
- if (option[0] != '.')
- return;
- if (GNUNET_OK !=
- GNUNET_STRINGS_string_to_data (value,
- strlen (value),
- &pk,
- sizeof(pk)))
- {
- GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
- section,
- option,
- _ (
- "Properly base32-encoded public key required"));
- return;
- }
- tld = GNUNET_new (struct GNS_TopLevelDomain);
- tld->tld = GNUNET_strdup (&option[1]);
- tld->pkey = pk;
- GNUNET_CONTAINER_DLL_insert (tld_head,
- tld_tail,
- tld);
- }
- /**
- * Process GNS requests.
- *
- * @param cls closure
- * @param server the initialized server
- * @param c configuration to use
- */
- static void
- run (void *cls,
- const struct GNUNET_CONFIGURATION_Handle *c,
- struct GNUNET_SERVICE_Handle *service)
- {
- unsigned long long max_parallel_bg_queries = 16;
- GNUNET_CONFIGURATION_iterate_section_values (c,
- "gns",
- &read_service_conf,
- NULL);
- v6_enabled = GNUNET_NETWORK_test_pf (PF_INET6);
- v4_enabled = GNUNET_NETWORK_test_pf (PF_INET);
- namecache_handle = GNUNET_NAMECACHE_connect (c);
- if (NULL == namecache_handle)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
- _ ("Failed to connect to the namecache!\n"));
- GNUNET_SCHEDULER_shutdown ();
- return;
- }
- if (GNUNET_OK ==
- GNUNET_CONFIGURATION_get_value_number (c,
- "gns",
- "MAX_PARALLEL_BACKGROUND_QUERIES",
- &max_parallel_bg_queries))
- {
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Number of allowed parallel background queries: %llu\n",
- max_parallel_bg_queries);
- }
- dht_handle = GNUNET_DHT_connect (c,
- (unsigned int) max_parallel_bg_queries);
- if (NULL == dht_handle)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
- _ ("Could not connect to DHT!\n"));
- GNUNET_SCHEDULER_add_now (&shutdown_task,
- NULL);
- return;
- }
- GNS_resolver_init (namecache_handle,
- dht_handle,
- c,
- max_parallel_bg_queries);
- if ((GNUNET_YES ==
- GNUNET_CONFIGURATION_get_value_yesno (c,
- "gns",
- "INTERCEPT_DNS")) &&
- (GNUNET_SYSERR ==
- GNS_interceptor_init (c)))
- {
- GNUNET_break (0);
- GNUNET_SCHEDULER_add_now (&shutdown_task,
- NULL);
- return;
- }
- statistics = GNUNET_STATISTICS_create ("gns",
- c);
- GNUNET_SCHEDULER_add_shutdown (&shutdown_task,
- NULL);
- }
- /**
- * Define "main" method using service macro.
- */
- GNUNET_SERVICE_MAIN
- ("gns",
- GNUNET_SERVICE_OPTION_NONE,
- &run,
- &client_connect_cb,
- &client_disconnect_cb,
- NULL,
- GNUNET_MQ_hd_var_size (lookup,
- GNUNET_MESSAGE_TYPE_GNS_LOOKUP,
- struct LookupMessage,
- NULL),
- GNUNET_MQ_handler_end ());
- /* end of gnunet-service-gns.c */
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