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Diffstat (limited to 'src/util/resolver_api.c')
| -rw-r--r-- | src/util/resolver_api.c | 972 |
1 files changed, 972 insertions, 0 deletions
diff --git a/src/util/resolver_api.c b/src/util/resolver_api.c new file mode 100644 index 0000000..9d5ae6c --- /dev/null +++ b/src/util/resolver_api.c @@ -0,0 +1,972 @@ +/* + This file is part of GNUnet. + (C) 2009, 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 2, 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 util/resolver_api.c + * @brief resolver for writing a tool + * @author Christian Grothoff + */ +#include "platform.h" +#include "gnunet_getopt_lib.h" +#include "gnunet_os_lib.h" +#include "gnunet_client_lib.h" +#include "gnunet_container_lib.h" +#include "gnunet_protocols.h" +#include "gnunet_resolver_service.h" +#include "gnunet_server_lib.h" +#include "resolver.h" + +#define LOG(kind,...) GNUNET_log_from (kind, "resolver-api", __VA_ARGS__) + +#define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "resolver-api", syscall) + +/** + * Maximum supported length for a hostname + */ +#define MAX_HOSTNAME 1024 + + +/** + * Possible hostnames for "loopback". + */ +static const char *loopback[] = { + "localhost", + "ip6-localnet", + NULL +}; + + +/** + * Configuration. + */ +static const struct GNUNET_CONFIGURATION_Handle *resolver_cfg; + +/** + * Our connection to the resolver service, created on-demand, but then + * persists until error or shutdown. + */ +static struct GNUNET_CLIENT_Connection *client; + +/** + * Head of DLL of requests. + */ +static struct GNUNET_RESOLVER_RequestHandle *req_head; + +/** + * Tail of DLL of requests. + */ +static struct GNUNET_RESOLVER_RequestHandle *req_tail; + +/** + * How long should we wait to reconnect? + */ +static struct GNUNET_TIME_Relative backoff; + +/** + * Task for reconnecting. + */ +static GNUNET_SCHEDULER_TaskIdentifier r_task; + +/** + * Task ID of shutdown task; only present while we have a + * connection to the resolver service. + */ +static GNUNET_SCHEDULER_TaskIdentifier s_task; + + +/** + * Handle to a request given to the resolver. Can be used to cancel + * the request prior to the timeout or successful execution. Also + * used to track our internal state for the request. + */ +struct GNUNET_RESOLVER_RequestHandle +{ + + /** + * Next entry in DLL of requests. + */ + struct GNUNET_RESOLVER_RequestHandle *next; + + /** + * Previous entry in DLL of requests. + */ + struct GNUNET_RESOLVER_RequestHandle *prev; + + /** + * Callback if this is an name resolution request, + * otherwise NULL. + */ + GNUNET_RESOLVER_AddressCallback addr_callback; + + /** + * Callback if this is a reverse lookup request, + * otherwise NULL. + */ + GNUNET_RESOLVER_HostnameCallback name_callback; + + /** + * Closure for the respective "callback". + */ + void *cls; + + /** + * When should this request time out? + */ + struct GNUNET_TIME_Absolute timeout; + + /** + * Task handle for numeric lookups. + */ + GNUNET_SCHEDULER_TaskIdentifier task; + + /** + * Desired address family. + */ + int af; + + /** + * Has this request been transmitted to the service? + * GNUNET_YES if transmitted + * GNUNET_YES if not transmitted + * GNUNET_SYSERR when request was canceled + */ + int was_transmitted; + + /** + * Did we add this request to the queue? + */ + int was_queued; + + /** + * Desired direction (IP to name or name to IP) + */ + int direction; + + /** + * GNUNET_YES if a response was received + */ + int received_response; + + /** + * Length of the data that follows this struct. + */ + size_t data_len; +}; + + +/** + * Check that the resolver service runs on localhost + * (or equivalent). + */ +static void +check_config () +{ + char *hostname; + unsigned int i; + struct sockaddr_in v4; + struct sockaddr_in6 v6; + + memset (&v4, 0, sizeof (v4)); + v4.sin_addr.s_addr = htonl (INADDR_LOOPBACK); + v4.sin_family = AF_INET; +#if HAVE_SOCKADDR_IN_SIN_LEN + v4.sin_len = sizeof (v4); +#endif + memset (&v6, 0, sizeof (v6)); + v6.sin6_family = AF_INET6; +#if HAVE_SOCKADDR_IN_SIN_LEN + v6.sin6_len = sizeof (v6); +#endif + if (GNUNET_OK != + GNUNET_CONFIGURATION_get_value_string (resolver_cfg, "resolver", + "HOSTNAME", &hostname)) + { + LOG (GNUNET_ERROR_TYPE_ERROR, + _("Must specify `%s' for `%s' in configuration!\n"), "HOSTNAME", + "resolver"); + GNUNET_assert (0); + } + if ((1 != inet_pton (AF_INET, hostname, &v4)) || + (1 != inet_pton (AF_INET6, hostname, &v6))) + { + GNUNET_free (hostname); + return; + } + i = 0; + while (loopback[i] != NULL) + if (0 == strcasecmp (loopback[i++], hostname)) + { + GNUNET_free (hostname); + return; + } + LOG (GNUNET_ERROR_TYPE_ERROR, + _ + ("Must specify `%s' or numeric IP address for `%s' of `%s' in configuration!\n"), + "localhost", "HOSTNAME", "resolver"); + GNUNET_free (hostname); + GNUNET_assert (0); +} + + +/** + * Create the connection to the resolver service. + * + * @param cfg configuration to use + */ +void +GNUNET_RESOLVER_connect (const struct GNUNET_CONFIGURATION_Handle *cfg) +{ + GNUNET_assert (NULL != cfg); + backoff = GNUNET_TIME_UNIT_MILLISECONDS; + resolver_cfg = cfg; + check_config (); +} + + +/** + * Destroy the connection to the resolver service. + */ +void +GNUNET_RESOLVER_disconnect () +{ + GNUNET_assert (NULL == req_head); + GNUNET_assert (NULL == req_tail); + if (NULL != client) + { +#if DEBUG_RESOLVER + LOG (GNUNET_ERROR_TYPE_DEBUG, "Disconnecting from DNS service\n"); +#endif + GNUNET_CLIENT_disconnect (client, GNUNET_NO); + client = NULL; + } + if (r_task != GNUNET_SCHEDULER_NO_TASK) + { + GNUNET_SCHEDULER_cancel (r_task); + r_task = GNUNET_SCHEDULER_NO_TASK; + } + if (s_task != GNUNET_SCHEDULER_NO_TASK) + { + GNUNET_SCHEDULER_cancel (s_task); + s_task = GNUNET_SCHEDULER_NO_TASK; + } +} + + +/** + * Convert IP address to string without DNS resolution. + * + * @param af address family + * @param ip the address + * @param ip_len number of bytes in ip + * @return address as a string, NULL on error + */ +static char * +no_resolve (int af, + const void *ip, socklen_t ip_len) +{ + char buf[INET6_ADDRSTRLEN]; + + switch (af) + { + case AF_INET: + if (ip_len != sizeof (struct in_addr)) + return NULL; + if (NULL == + inet_ntop (AF_INET, ip, buf, sizeof (buf))) + { + LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "inet_ntop"); + return NULL; + } + break; + case AF_INET6: + if (ip_len != sizeof (struct in6_addr)) + return NULL; + if (NULL == + inet_ntop (AF_INET6, ip, buf, sizeof (buf))) + { + LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "inet_ntop"); + return NULL; + } + break; + default: + GNUNET_break (0); + return NULL; + } + return GNUNET_strdup (buf); +} + + +/** + * Adjust exponential back-off and reconnect to the service. + */ +static void +reconnect (); + + +/** + * Process pending requests to the resolver. + */ +static void +process_requests (); + + +/** + * Process response with a hostname for a DNS lookup. + * + * @param cls our "struct GNUNET_RESOLVER_RequestHandle" context + * @param msg message with the hostname, NULL on error + */ +static void +handle_response (void *cls, const struct GNUNET_MessageHeader *msg) +{ + struct GNUNET_RESOLVER_RequestHandle *rh = cls; + uint16_t size; + +#if DEBUG_RESOLVER + LOG (GNUNET_ERROR_TYPE_DEBUG, "Receiving response from DNS service\n"); +#endif + if (msg == NULL) + { + char buf[INET6_ADDRSTRLEN]; + + if (NULL != rh->name_callback) + LOG (GNUNET_ERROR_TYPE_INFO, + _("Timeout trying to resolve IP address `%s'.\n"), + inet_ntop (rh->af, (const void *) &rh[1], buf, sizeof(buf))); + else + LOG (GNUNET_ERROR_TYPE_INFO, + _("Timeout trying to resolve hostname `%s'.\n"), + (const char *) &rh[1]); + /* check if request was canceled */ + if (rh->was_transmitted != GNUNET_SYSERR) + { + if (NULL != rh->name_callback) + { + /* no reverse lookup was successful, return ip as string */ + if (rh->received_response == GNUNET_NO) + rh->name_callback (rh->cls, + no_resolve (rh->af, + &rh[1], + rh->data_len)); + /* at least one reverse lookup was successful */ + else + rh->name_callback (rh->cls, NULL); + } + if (NULL != rh->addr_callback) + rh->addr_callback (rh->cls, NULL, 0); + } + GNUNET_CONTAINER_DLL_remove (req_head, req_tail, rh); + GNUNET_free (rh); + GNUNET_CLIENT_disconnect (client, GNUNET_NO); + client = NULL; + reconnect (); + return; + } + if (GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE != ntohs (msg->type)) + { + GNUNET_break (0); + GNUNET_CLIENT_disconnect (client, GNUNET_NO); + client = NULL; + reconnect (); + return; + } + size = ntohs (msg->size); + /* message contains not data, just header */ + if (size == sizeof (struct GNUNET_MessageHeader)) + { + /* check if request was canceled */ + if (rh->was_transmitted != GNUNET_SYSERR) + { + if (NULL != rh->name_callback) + rh->name_callback (rh->cls, NULL); + if (NULL != rh->addr_callback) + rh->addr_callback (rh->cls, NULL, 0); + } + GNUNET_CONTAINER_DLL_remove (req_head, req_tail, rh); + GNUNET_free (rh); + process_requests (); + return; + } + /* return reverse lookup results to caller */ + if (NULL != rh->name_callback) + { + const char *hostname; + + hostname = (const char *) &msg[1]; + if (hostname[size - sizeof (struct GNUNET_MessageHeader) - 1] != '\0') + { + GNUNET_break (0); + if (rh->was_transmitted != GNUNET_SYSERR) + rh->name_callback (rh->cls, NULL); + GNUNET_CONTAINER_DLL_remove (req_head, req_tail, rh); + GNUNET_free (rh); + GNUNET_CLIENT_disconnect (client, GNUNET_NO); + client = NULL; + reconnect (); + return; + } +#if DEBUG_RESOLVER + LOG (GNUNET_ERROR_TYPE_DEBUG, _("Resolver returns `%s' for IP `%s'.\n"), + hostname, GNUNET_a2s ((const void *) &rh[1], rh->data_len)); +#endif + if (rh->was_transmitted != GNUNET_SYSERR) + rh->name_callback (rh->cls, hostname); + rh->received_response = GNUNET_YES; + GNUNET_CLIENT_receive (client, &handle_response, rh, + GNUNET_TIME_absolute_get_remaining (rh->timeout)); + } + /* return lookup results to caller */ + if (NULL != rh->addr_callback) + { + struct sockaddr_in v4; + struct sockaddr_in6 v6; + const struct sockaddr *sa; + socklen_t salen; + const void *ip; + size_t ip_len; + + ip = &msg[1]; + ip_len = size - sizeof (struct GNUNET_MessageHeader); + if (ip_len == sizeof (struct in_addr)) + { + memset (&v4, 0, sizeof (v4)); + v4.sin_family = AF_INET; + v4.sin_addr = *(struct in_addr*) ip; +#if HAVE_SOCKADDR_IN_SIN_LEN + v4.sin_len = sizeof (v4); +#endif + salen = sizeof (v4); + sa = (const struct sockaddr *) &v4; + } + else if (ip_len == sizeof (struct in6_addr)) + { + memset (&v6, 0, sizeof (v6)); + v6.sin6_family = AF_INET6; + v6.sin6_addr = *(struct in6_addr*) ip; +#if HAVE_SOCKADDR_IN_SIN_LEN + v6.sin6_len = sizeof (v6); +#endif + salen = sizeof (v6); + sa = (const struct sockaddr *) &v6; + } + else + { + GNUNET_break (0); + if (rh->was_transmitted != GNUNET_SYSERR) + rh->addr_callback (rh->cls, NULL, 0); + GNUNET_CONTAINER_DLL_remove (req_head, req_tail, rh); + GNUNET_free (rh); + GNUNET_CLIENT_disconnect (client, GNUNET_NO); + client = NULL; + reconnect (); + return; + } + rh->addr_callback (rh->cls, sa, salen); + GNUNET_CLIENT_receive (client, &handle_response, rh, + GNUNET_TIME_absolute_get_remaining (rh->timeout)); + } +} + + +/** + * We've been asked to lookup the address for a hostname and were + * given a valid numeric string. Perform the callbacks for the + * numeric addresses. + * + * @param cls struct GNUNET_RESOLVER_RequestHandle for the request + * @param tc unused scheduler context + */ +static void +numeric_resolution (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) +{ + struct GNUNET_RESOLVER_RequestHandle *rh = cls; + struct sockaddr_in v4; + struct sockaddr_in6 v6; + const char *hostname; + + memset (&v4, 0, sizeof (v4)); + v4.sin_family = AF_INET; +#if HAVE_SOCKADDR_IN_SIN_LEN + v4.sin_len = sizeof (v4); +#endif + memset (&v6, 0, sizeof (v6)); + v6.sin6_family = AF_INET6; +#if HAVE_SOCKADDR_IN_SIN_LEN + v6.sin6_len = sizeof (v6); +#endif + hostname = (const char *) &rh[1]; + if (((rh->af == AF_UNSPEC) || (rh->af == AF_INET)) && + (1 == inet_pton (AF_INET, hostname, &v4.sin_addr))) + { + rh->addr_callback (rh->cls, (const struct sockaddr *) &v4, sizeof (v4)); + if ((rh->af == AF_UNSPEC) && + (1 == inet_pton (AF_INET6, hostname, &v6.sin6_addr))) + { + /* this can happen on some systems IF "hostname" is "localhost" */ + rh->addr_callback (rh->cls, (const struct sockaddr *) &v6, sizeof (v6)); + } + rh->addr_callback (rh->cls, NULL, 0); + GNUNET_free (rh); + return; + } + if (((rh->af == AF_UNSPEC) || (rh->af == AF_INET6)) && + (1 == inet_pton (AF_INET6, hostname, &v6.sin6_addr))) + { + rh->addr_callback (rh->cls, (const struct sockaddr *) &v6, sizeof (v6)); + rh->addr_callback (rh->cls, NULL, 0); + GNUNET_free (rh); + return; + } + /* why are we here? this task should not have been scheduled! */ + GNUNET_assert (0); + GNUNET_free (rh); +} + + +/** + * We've been asked to lookup the address for a hostname and were + * given a variant of "loopback". Perform the callbacks for the + * respective loopback numeric addresses. + * + * @param cls struct GNUNET_RESOLVER_RequestHandle for the request + * @param tc unused scheduler context + */ +static void +loopback_resolution (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) +{ + struct GNUNET_RESOLVER_RequestHandle *rh = cls; + struct sockaddr_in v4; + struct sockaddr_in6 v6; + + memset (&v4, 0, sizeof (v4)); + v4.sin_addr.s_addr = htonl (INADDR_LOOPBACK); + v4.sin_family = AF_INET; +#if HAVE_SOCKADDR_IN_SIN_LEN + v4.sin_len = sizeof (v4); +#endif + memset (&v6, 0, sizeof (v6)); + v6.sin6_family = AF_INET6; +#if HAVE_SOCKADDR_IN_SIN_LEN + v6.sin6_len = sizeof (v6); +#endif + v6.sin6_addr = in6addr_loopback; + switch (rh->af) + { + case AF_INET: + rh->addr_callback (rh->cls, (const struct sockaddr *) &v4, sizeof (v4)); + break; + case AF_INET6: + rh->addr_callback (rh->cls, (const struct sockaddr *) &v6, sizeof (v6)); + break; + case AF_UNSPEC: + rh->addr_callback (rh->cls, (const struct sockaddr *) &v6, sizeof (v6)); + rh->addr_callback (rh->cls, (const struct sockaddr *) &v4, sizeof (v4)); + break; + default: + GNUNET_break (0); + break; + } + rh->addr_callback (rh->cls, NULL, 0); + GNUNET_free (rh); +} + + +/** + * Task executed on system shutdown. + */ +static void +shutdown_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) +{ + s_task = GNUNET_SCHEDULER_NO_TASK; + GNUNET_RESOLVER_disconnect (); +} + + +/** + * Process pending requests to the resolver. + */ +static void +process_requests () +{ + struct GNUNET_RESOLVER_GetMessage *msg; + char buf[GNUNET_SERVER_MAX_MESSAGE_SIZE - 1]; + struct GNUNET_RESOLVER_RequestHandle *rh; + + if (NULL == client) + { + reconnect (); + return; + } + rh = req_head; + if (NULL == rh) + { + /* nothing to do, release socket really soon if there is nothing + * else happening... */ + s_task = + GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MILLISECONDS, + &shutdown_task, NULL); + return; + } + if (GNUNET_YES == rh->was_transmitted) + return; /* waiting for reply */ + msg = (struct GNUNET_RESOLVER_GetMessage *) buf; + msg->header.size = + htons (sizeof (struct GNUNET_RESOLVER_GetMessage) + rh->data_len); + msg->header.type = htons (GNUNET_MESSAGE_TYPE_RESOLVER_REQUEST); + msg->direction = htonl (rh->direction); + msg->af = htonl (rh->af); + memcpy (&msg[1], &rh[1], rh->data_len); +#if DEBUG_RESOLVER + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Transmitting DNS resolution request to DNS service\n"); +#endif + if (GNUNET_OK != + GNUNET_CLIENT_transmit_and_get_response (client, &msg->header, + GNUNET_TIME_absolute_get_remaining + (rh->timeout), GNUNET_YES, + &handle_response, rh)) + { + GNUNET_CLIENT_disconnect (client, GNUNET_NO); + client = NULL; + reconnect (); + return; + } + rh->was_transmitted = GNUNET_YES; +} + + +/** + * Now try to reconnect to the resolver service. + * + * @param cls NULL + * @param tc scheduler context + */ +static void +reconnect_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) +{ + r_task = GNUNET_SCHEDULER_NO_TASK; + if (NULL == req_head) + return; /* no work pending */ + if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)) + return; +#if DEBUG_RESOLVER + LOG (GNUNET_ERROR_TYPE_DEBUG, "Trying to connect to DNS service\n"); +#endif + client = GNUNET_CLIENT_connect ("resolver", resolver_cfg); + if (NULL == client) + { + LOG (GNUNET_ERROR_TYPE_DEBUG, "Failed to connect, will try again later\n"); + reconnect (); + return; + } + process_requests (); +} + + +/** + * Adjust exponential back-off and reconnect to the service. + */ +static void +reconnect () +{ + struct GNUNET_RESOLVER_RequestHandle *rh; + + if (GNUNET_SCHEDULER_NO_TASK != r_task) + return; + GNUNET_assert (NULL == client); + if (NULL != (rh = req_head)) + { + switch (rh->was_transmitted) + { + case GNUNET_NO: + /* nothing more to do */ + break; + case GNUNET_YES: + /* disconnected, transmit again! */ + rh->was_transmitted = GNUNET_NO; + break; + case GNUNET_SYSERR: + /* request was cancelled, remove entirely */ + GNUNET_CONTAINER_DLL_remove (req_head, req_tail, rh); + GNUNET_free (rh); + break; + default: + GNUNET_assert (0); + break; + } + } +#if DEBUG_RESOLVER + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Will try to connect to DNS service in %llu ms\n", + (unsigned long long) backoff.rel_value); +#endif + GNUNET_assert (NULL != resolver_cfg); + r_task = GNUNET_SCHEDULER_add_delayed (backoff, &reconnect_task, NULL); + backoff = GNUNET_TIME_relative_multiply (backoff, 2); +} + + +/** + * Convert a string to one or more IP addresses. + * + * @param hostname the hostname to resolve + * @param af AF_INET or AF_INET6; use AF_UNSPEC for "any" + * @param callback function to call with addresses + * @param callback_cls closure for callback + * @param timeout how long to try resolving + * @return handle that can be used to cancel the request, NULL on error + */ +struct GNUNET_RESOLVER_RequestHandle * +GNUNET_RESOLVER_ip_get (const char *hostname, int af, + struct GNUNET_TIME_Relative timeout, + GNUNET_RESOLVER_AddressCallback callback, + void *callback_cls) +{ + struct GNUNET_RESOLVER_RequestHandle *rh; + size_t slen; + unsigned int i; + struct in_addr v4; + struct in6_addr v6; + + slen = strlen (hostname) + 1; + if (slen + sizeof (struct GNUNET_RESOLVER_GetMessage) >= + GNUNET_SERVER_MAX_MESSAGE_SIZE) + { + GNUNET_break (0); + return NULL; + } + rh = GNUNET_malloc (sizeof (struct GNUNET_RESOLVER_RequestHandle) + slen); + rh->af = af; + rh->addr_callback = callback; + rh->cls = callback_cls; + memcpy (&rh[1], hostname, slen); + rh->data_len = slen; + rh->timeout = GNUNET_TIME_relative_to_absolute (timeout); + rh->direction = GNUNET_NO; + /* first, check if this is a numeric address */ + if (((1 == inet_pton (AF_INET, hostname, &v4)) && + ((af == AF_INET) || (af == AF_UNSPEC))) || + ((1 == inet_pton (AF_INET6, hostname, &v6)) && + ((af == AF_INET6) || (af == AF_UNSPEC)))) + { + rh->task = GNUNET_SCHEDULER_add_now (&numeric_resolution, rh); + return rh; + } + /* then, check if this is a loopback address */ + i = 0; + while (loopback[i] != NULL) + if (0 == strcasecmp (loopback[i++], hostname)) + { + rh->task = GNUNET_SCHEDULER_add_now (&loopback_resolution, rh); + return rh; + } + GNUNET_CONTAINER_DLL_insert_tail (req_head, req_tail, rh); + rh->was_queued = GNUNET_YES; + if (s_task != GNUNET_SCHEDULER_NO_TASK) + { + GNUNET_SCHEDULER_cancel (s_task); + s_task = GNUNET_SCHEDULER_NO_TASK; + } + process_requests (); + return rh; +} + + +/** + * We've been asked to convert an address to a string without + * a reverse lookup. Do it. + * + * @param cls struct GNUNET_RESOLVER_RequestHandle for the request + * @param tc unused scheduler context + */ +static void +numeric_reverse (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) +{ + struct GNUNET_RESOLVER_RequestHandle *rh = cls; + char *result; + + result = no_resolve (rh->af, &rh[1], rh->data_len); +#if DEBUG_RESOLVER + LOG (GNUNET_ERROR_TYPE_DEBUG, _("Resolver returns `%s'.\n"), result); +#endif + if (result != NULL) + { + rh->name_callback (rh->cls, result); + GNUNET_free (result); + } + rh->name_callback (rh->cls, NULL); + GNUNET_free (rh); +} + + +/** + * Get an IP address as a string. + * + * @param sa host address + * @param salen length of host address + * @param do_resolve use GNUNET_NO to return numeric hostname + * @param timeout how long to try resolving + * @param callback function to call with hostnames + * last callback is NULL when finished + * @param cls closure for callback + * @return handle that can be used to cancel the request + */ +struct GNUNET_RESOLVER_RequestHandle * +GNUNET_RESOLVER_hostname_get (const struct sockaddr *sa, socklen_t salen, + int do_resolve, + struct GNUNET_TIME_Relative timeout, + GNUNET_RESOLVER_HostnameCallback callback, + void *cls) +{ + struct GNUNET_RESOLVER_RequestHandle *rh; + size_t ip_len; + const void *ip; + + check_config (); + switch (sa->sa_family) + { + case AF_INET: + ip_len = sizeof (struct in_addr); + ip = &((const struct sockaddr_in*)sa)->sin_addr; + break; + case AF_INET6: + ip_len = sizeof (struct in6_addr); + ip = &((const struct sockaddr_in6*)sa)->sin6_addr; + break; + default: + GNUNET_break (0); + return NULL; + } + rh = GNUNET_malloc (sizeof (struct GNUNET_RESOLVER_RequestHandle) + salen); + rh->name_callback = callback; + rh->cls = cls; + rh->af = sa->sa_family; + rh->timeout = GNUNET_TIME_relative_to_absolute (timeout); + memcpy (&rh[1], ip, ip_len); + rh->data_len = ip_len; + rh->direction = GNUNET_YES; + rh->received_response = GNUNET_NO; + if (GNUNET_NO == do_resolve) + { + rh->task = GNUNET_SCHEDULER_add_now (&numeric_reverse, rh); + return rh; + } + GNUNET_CONTAINER_DLL_insert_tail (req_head, req_tail, rh); + rh->was_queued = GNUNET_YES; + if (s_task != GNUNET_SCHEDULER_NO_TASK) + { + GNUNET_SCHEDULER_cancel (s_task); + s_task = GNUNET_SCHEDULER_NO_TASK; + } + process_requests (); + return rh; +} + + +/** + * Get local fully qualified af name + * + * @return fqdn + */ +char * +GNUNET_RESOLVER_local_fqdn_get () +{ + struct hostent *host; + char hostname[GNUNET_OS_get_hostname_max_length () + 1]; + + if (0 != gethostname (hostname, sizeof (hostname) - 1)) + { + LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK, + "gethostname"); + return NULL; + } +#if DEBUG_RESOLVER + LOG (GNUNET_ERROR_TYPE_DEBUG, _("Resolving our FQDN `%s'\n"), hostname); +#endif + host = gethostbyname (hostname); + if (NULL == host) + { + LOG (GNUNET_ERROR_TYPE_ERROR, _("Could not resolve our FQDN : %s\n"), + hstrerror (h_errno)); + return NULL; + } + return GNUNET_strdup (host->h_name); +} + + +/** + * Looking our own hostname. + * + * @param af AF_INET or AF_INET6; use AF_UNSPEC for "any" + * @param callback function to call with addresses + * @param cls closure for callback + * @param timeout how long to try resolving + * @return handle that can be used to cancel the request, NULL on error + */ +struct GNUNET_RESOLVER_RequestHandle * +GNUNET_RESOLVER_hostname_resolve (int af, + struct GNUNET_TIME_Relative timeout, + GNUNET_RESOLVER_AddressCallback callback, + void *cls) +{ + char hostname[GNUNET_OS_get_hostname_max_length () + 1]; + + if (0 != gethostname (hostname, sizeof (hostname) - 1)) + { + LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK, + "gethostname"); + return NULL; + } +#if DEBUG_RESOLVER + LOG (GNUNET_ERROR_TYPE_DEBUG, _("Resolving our hostname `%s'\n"), hostname); +#endif + return GNUNET_RESOLVER_ip_get (hostname, af, timeout, callback, cls); +} + + +/** + * Cancel a request that is still pending with the resolver. + * Note that a client MUST NOT cancel a request that has + * been completed (i.e, the callback has been called to + * signal timeout or the final result). + * + * @param rh handle of request to cancel + */ +void +GNUNET_RESOLVER_request_cancel (struct GNUNET_RESOLVER_RequestHandle *rh) +{ + if (rh->task != GNUNET_SCHEDULER_NO_TASK) + { + GNUNET_SCHEDULER_cancel (rh->task); + rh->task = GNUNET_SCHEDULER_NO_TASK; + } + if (rh->was_transmitted == GNUNET_NO) + { + if (rh->was_queued == GNUNET_YES) + GNUNET_CONTAINER_DLL_remove (req_head, req_tail, rh); + GNUNET_free (rh); + return; + } + GNUNET_assert (rh->was_transmitted == GNUNET_YES); + rh->was_transmitted = GNUNET_SYSERR; /* mark as cancelled */ +} + + +/* end of resolver_api.c */ |