X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=src%2Futil%2Fresolver_api.c;h=f33c31f1c8ccedf328f4526ba6096088b004a594;hb=f2d1b4fa8a76b1fdf9830b2e61d18b8c92e3eb88;hp=c32fc58facf0216089bb20b5f6cc53116f2babc1;hpb=cb6282d675457b7e3ac12c2615789f125b61e2b2;p=oweals%2Fgnunet.git diff --git a/src/util/resolver_api.c b/src/util/resolver_api.c index c32fc58fa..f33c31f1c 100644 --- a/src/util/resolver_api.c +++ b/src/util/resolver_api.c @@ -1,10 +1,10 @@ /* This file is part of GNUnet. - (C) 2009 Christian Grothoff (and other contributing authors) + Copyright (C) 2009-2016 GNUnet e.V. 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 + 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 @@ -14,8 +14,8 @@ 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. + Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, + Boston, MA 02110-1301, USA. */ /** @@ -24,13 +24,14 @@ * @author Christian Grothoff */ #include "platform.h" -#include "gnunet_getopt_lib.h" -#include "gnunet_client_lib.h" +#include "gnunet_util_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, "util-resolver-api", __VA_ARGS__) + +#define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "util-resolver-api", syscall) /** * Maximum supported length for a hostname @@ -48,6 +49,44 @@ static const char *loopback[] = { }; +/** + * 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_MQ_Handle *mq; + +/** + * 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 struct GNUNET_SCHEDULER_Task *r_task; + +/** + * Task ID of shutdown task; only present while we have a + * connection to the resolver service. + */ +static struct GNUNET_SCHEDULER_Task *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 @@ -56,6 +95,16 @@ static const char *loopback[] = { 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. @@ -69,680 +118,1050 @@ struct GNUNET_RESOLVER_RequestHandle GNUNET_RESOLVER_HostnameCallback name_callback; /** - * Closure for the respective "callback". + * Closure for the callbacks. */ void *cls; /** - * Our connection to the resolver service. + * When should this request time out? */ - struct GNUNET_CLIENT_Connection *client; + struct GNUNET_TIME_Absolute timeout; /** - * Our scheduler. + * Task handle for making reply callbacks in numeric lookups + * asynchronous, and for timeout handling. */ - struct GNUNET_SCHEDULER_Handle *sched; + struct GNUNET_SCHEDULER_Task *task; /** - * Name of the host that we are resolving. + * Desired address family. */ - const char *hostname; + int af; /** - * When should this request time out? + * Has this request been transmitted to the service? + * #GNUNET_YES if transmitted + * #GNUNET_YES if not transmitted + * #GNUNET_SYSERR when request was canceled */ - struct GNUNET_TIME_Absolute timeout; + int was_transmitted; /** - * Task handle for numeric lookups. + * Did we add this request to the queue? */ - GNUNET_SCHEDULER_TaskIdentifier task; + int was_queued; /** - * Desired address family. - */ - int domain; + * Desired direction (IP to name or name to IP) + */ + int direction; /** - * Length of the "struct sockaddr" that follows this - * struct (only for reverse lookup). + * #GNUNET_YES if a response was received */ - socklen_t salen; + 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). + * + * @return #GNUNET_OK if the resolver is properly configured, + * #GNUNET_SYSERR otherwise. */ -static void -check_config (const struct GNUNET_CONFIGURATION_Handle *cfg) +static int +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); + 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); + v4.sin_len = sizeof (v4); #endif - memset (&v6, 0, sizeof(v6)); + memset (&v6, 0, sizeof (v6)); v6.sin6_family = AF_INET6; #if HAVE_SOCKADDR_IN_SIN_LEN - v6.sin6_len = sizeof(v6); + v6.sin6_len = sizeof (v6); #endif if (GNUNET_OK != - GNUNET_CONFIGURATION_get_value_string (cfg, - "resolver", - "HOSTNAME", - &hostname)) - { - GNUNET_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_CONFIGURATION_get_value_string (resolver_cfg, + "resolver", + "HOSTNAME", + &hostname)) + { + LOG (GNUNET_ERROR_TYPE_INFO, + _("Missing `%s' for `%s' in configuration, DNS resolution will be unavailable.\n"), + "HOSTNAME", + "resolver"); + return GNUNET_SYSERR; + } + if ((1 == inet_pton (AF_INET, hostname, &v4)) || + (1 == inet_pton (AF_INET6, hostname, &v6))) + { + GNUNET_free (hostname); + return GNUNET_OK; + } + i = 0; + while (NULL != loopback[i]) + if (0 == strcasecmp (loopback[i++], hostname)) { GNUNET_free (hostname); - return; + return GNUNET_OK; } - i = 0; - while (loopback[i] != NULL) - if (0 == strcasecmp (loopback[i++], hostname)) - { - GNUNET_free (hostname); - return; - } - GNUNET_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); + LOG (GNUNET_ERROR_TYPE_INFO, + _("Missing `%s' or numeric IP address for `%s' of `%s' in configuration, DNS resolution will be unavailable.\n"), + "localhost", + "HOSTNAME", + "resolver"); + GNUNET_free (hostname); + return GNUNET_SYSERR; +} + + +/** + * 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; +} + + +/** + * Destroy the connection to the resolver service. + */ +void +GNUNET_RESOLVER_disconnect () +{ + struct GNUNET_RESOLVER_RequestHandle *rh; + + while (NULL != (rh = req_head)) + { + GNUNET_assert (GNUNET_SYSERR == rh->was_transmitted); + GNUNET_CONTAINER_DLL_remove (req_head, + req_tail, + rh); + GNUNET_free (rh); + } + if (NULL != mq) + { + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Disconnecting from DNS service\n"); + GNUNET_MQ_destroy (mq); + mq = NULL; + } + if (NULL != r_task) + { + GNUNET_SCHEDULER_cancel (r_task); + r_task = NULL; + } + if (NULL != s_task) + { + GNUNET_SCHEDULER_cancel (s_task); + s_task = NULL; + } +} + + +/** + * Task executed on system shutdown. + */ +static void +shutdown_task (void *cls) +{ + s_task = NULL; + GNUNET_RESOLVER_disconnect (); + backoff = GNUNET_TIME_UNIT_MILLISECONDS; +} + + +/** + * Consider disconnecting if we have no further requests pending. + */ +static void +check_disconnect () +{ + struct GNUNET_RESOLVER_RequestHandle *rh; + + for (rh = req_head; NULL != rh; rh = rh->next) + if (GNUNET_SYSERR != rh->was_transmitted) + return; + if (NULL != r_task) + { + GNUNET_SCHEDULER_cancel (r_task); + r_task = NULL; + } + if (NULL != s_task) + return; + s_task = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MILLISECONDS, + &shutdown_task, + NULL); } /** * Convert IP address to string without DNS resolution. * - * @param sa the address - * @param salen number of bytes in sa + * @param af address family + * @param ip the address + * @param ip_len number of bytes in @a ip * @return address as a string, NULL on error */ static char * -no_resolve (const struct sockaddr *sa, socklen_t salen) +no_resolve (int af, + const void *ip, + socklen_t ip_len) { - char *ret; - char inet4[INET_ADDRSTRLEN]; - char inet6[INET6_ADDRSTRLEN]; + char buf[INET6_ADDRSTRLEN]; - if (salen < sizeof (struct sockaddr)) - return NULL; - switch (sa->sa_family) + switch (af) + { + case AF_INET: + if (ip_len != sizeof (struct in_addr)) + return NULL; + if (NULL == + inet_ntop (AF_INET, ip, buf, sizeof (buf))) { - case AF_INET: - if (salen != sizeof (struct sockaddr_in)) - return NULL; - inet_ntop (AF_INET, - &((struct sockaddr_in *) sa)->sin_addr, - inet4, INET_ADDRSTRLEN); - ret = GNUNET_strdup (inet4); - break; - case AF_INET6: - if (salen != sizeof (struct sockaddr_in6)) - return NULL; - inet_ntop (AF_INET6, - &((struct sockaddr_in6 *) sa)->sin6_addr, - inet6, INET6_ADDRSTRLEN); - ret = GNUNET_strdup (inet6); - break; - default: - ret = NULL; - break; + 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; } - return ret; + break; + default: + GNUNET_break (0); + return NULL; + } + return GNUNET_strdup (buf); } /** - * Process the reply from the resolver (which is presumably - * the numeric IP address for a name resolution request). + * Adjust exponential back-off and reconnect to the service. + */ +static void +reconnect (void); + + +/** + * Generic error handler, called with the appropriate error code and + * the same closure specified at the creation of the message queue. + * Not every message queue implementation supports an error handler. * - * @param cls the "GNUNET_RESOLVER_RequestHandle" for which this is a reply - * @param msg reply from the resolver or NULL on error + * @param cls NULL + * @param error error code */ static void -handle_address_response (void *cls, const struct GNUNET_MessageHeader *msg) +mq_error_handler (void *cls, + enum GNUNET_MQ_Error error) { - struct GNUNET_RESOLVER_RequestHandle *rh = cls; - uint16_t size; - const struct sockaddr *sa; - socklen_t salen; + GNUNET_MQ_destroy (mq); + mq = NULL; + LOG (GNUNET_ERROR_TYPE_DEBUG, + "MQ error, reconnecting\n"); + reconnect (); +} + + +/** + * Process pending requests to the resolver. + */ +static void +process_requests () +{ + struct GNUNET_RESOLVER_GetMessage *msg; + struct GNUNET_MQ_Envelope *env; + struct GNUNET_RESOLVER_RequestHandle *rh = req_head; + + if (NULL == mq) + { + reconnect (); + return; + } + 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_NO != rh->was_transmitted) + return; /* waiting for reply */ + env = GNUNET_MQ_msg_extra (msg, + rh->data_len, + GNUNET_MESSAGE_TYPE_RESOLVER_REQUEST); + msg->direction = htonl (rh->direction); + msg->af = htonl (rh->af); + GNUNET_memcpy (&msg[1], + &rh[1], + rh->data_len); + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Transmitting DNS resolution request to DNS service\n"); + GNUNET_MQ_send (mq, + env); + rh->was_transmitted = GNUNET_YES; +} + + +/** + * Check validity of response with a hostname for a DNS lookup. + * + * @param cls NULL + * @param msg message with the hostname + */ +static int +check_response (void *cls, + const struct GNUNET_MessageHeader *msg) +{ + /* implemented in #handle_response() for now */ + return GNUNET_OK; +} - if (msg == NULL) +/** + * Check validity of response with a hostname for a DNS lookup. + * NOTE: right now rather messy, might want to use different + * message types for different response formats in the future. + * + * @param cls NULL + * @param msg message with the response + */ +static void +handle_response (void *cls, + const struct GNUNET_MessageHeader *msg) +{ + struct GNUNET_RESOLVER_RequestHandle *rh = req_head; + uint16_t size; + char *nret; + + size = ntohs (msg->size); + if (size == sizeof (struct GNUNET_MessageHeader)) + { + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Received empty response from DNS service\n"); + /* message contains not data, just header; end of replies */ + /* check if request was canceled */ + if (GNUNET_SYSERR != rh->was_transmitted) { - GNUNET_log (GNUNET_ERROR_TYPE_INFO, - _("Timeout trying to resolve hostname.\n")); - rh->addr_callback (rh->cls, NULL, 0); - GNUNET_CLIENT_disconnect (rh->client); - GNUNET_free (rh); - return; + /* no reverse lookup was successful, return IP as string */ + if (NULL != rh->name_callback) + { + if (GNUNET_NO == rh->received_response) + { + nret = no_resolve (rh->af, + &rh[1], + rh->data_len); + rh->name_callback (rh->cls, nret); + GNUNET_free (nret); + } + /* finally, make termination call */ + rh->name_callback (rh->cls, + NULL); + } + if (NULL != rh->addr_callback) + rh->addr_callback (rh->cls, + NULL, + 0); } - if (GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE != ntohs (msg->type)) + rh->was_transmitted = GNUNET_NO; + GNUNET_RESOLVER_request_cancel (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); - rh->addr_callback (rh->cls, NULL, 0); - GNUNET_CLIENT_disconnect (rh->client); - GNUNET_free (rh); + if (GNUNET_SYSERR != rh->was_transmitted) + rh->name_callback (rh->cls, + NULL); + rh->was_transmitted = GNUNET_NO; + GNUNET_RESOLVER_request_cancel (rh); + GNUNET_MQ_destroy (mq); + mq = NULL; + reconnect (); return; } - - size = ntohs (msg->size); - if (size == sizeof (struct GNUNET_MessageHeader)) + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Resolver returns `%s' for IP `%s'.\n", + hostname, + GNUNET_a2s ((const void *) &rh[1], + rh->data_len)); + if (rh->was_transmitted != GNUNET_SYSERR) + rh->name_callback (rh->cls, + hostname); + rh->received_response = GNUNET_YES; + } + /* 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)) { -#if DEBUG_RESOLVER - GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, - _("Received end message resolving hostname.\n")); + 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 - rh->addr_callback (rh->cls, NULL, 0); - GNUNET_CLIENT_disconnect (rh->client); - GNUNET_free (rh); - return; + 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; } - sa = (const struct sockaddr *) &msg[1]; - salen = size - sizeof (struct GNUNET_MessageHeader); - if (salen < sizeof (struct sockaddr)) + else { GNUNET_break (0); - rh->addr_callback (rh->cls, NULL, 0); - GNUNET_CLIENT_disconnect (rh->client); - GNUNET_free (rh); + if (GNUNET_SYSERR != rh->was_transmitted) + rh->addr_callback (rh->cls, + NULL, + 0); + rh->was_transmitted = GNUNET_NO; + GNUNET_RESOLVER_request_cancel (rh); + GNUNET_MQ_destroy (mq); + mq = NULL; + reconnect (); return; } -#if DEBUG_RESOLVER - { - char *ips = no_resolve (sa, salen); - GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, - "Resolver returns `%s'.\n", - ips); - GNUNET_free (ips); + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Received IP from DNS service\n"); + if (GNUNET_SYSERR != rh->was_transmitted) + rh->addr_callback (rh->cls, + sa, + salen); } -#endif - rh->addr_callback (rh->cls, sa, salen); - GNUNET_CLIENT_receive (rh->client, - &handle_address_response, - rh, - GNUNET_TIME_absolute_get_remaining (rh->timeout)); } /** - * We've been asked to lookup the address for a hostname and were + * 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 + * @param cls `struct GNUNET_RESOLVER_RequestHandle` for the request */ static void -numeric_resolution (void *cls, - const struct GNUNET_SCHEDULER_TaskContext *tc) +numeric_resolution (void *cls) { struct GNUNET_RESOLVER_RequestHandle *rh = cls; struct sockaddr_in v4; struct sockaddr_in6 v6; + const char *hostname; - memset (&v4, 0, sizeof(v4)); + rh->task = NULL; + memset (&v4, 0, sizeof (v4)); v4.sin_family = AF_INET; #if HAVE_SOCKADDR_IN_SIN_LEN - v4.sin_len = sizeof(v4); + v4.sin_len = sizeof (v4); #endif - memset (&v6, 0, sizeof(v6)); + memset (&v6, 0, sizeof (v6)); v6.sin6_family = AF_INET6; #if HAVE_SOCKADDR_IN_SIN_LEN - v6.sin6_len = sizeof(v6); + v6.sin6_len = sizeof (v6); #endif - - if ( ( (rh->domain == AF_UNSPEC) || (rh->domain == AF_INET) ) && - (1 == inet_pton (AF_INET, - rh->hostname, - &v4.sin_addr)) ) + 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*) &v4, - sizeof(v4)); - if ( (rh->domain == AF_UNSPEC) && - (1 == inet_pton (AF_INET6, - rh->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; + (const struct sockaddr *) &v6, + sizeof (v6)); } - if ( ( (rh->domain == AF_UNSPEC) || (rh->domain == AF_INET6) ) && + 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, - rh->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; - } + 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 + * 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 + * @param cls `struct GNUNET_RESOLVER_RequestHandle` for the request */ static void -loopback_resolution (void *cls, - const struct GNUNET_SCHEDULER_TaskContext *tc) +loopback_resolution (void *cls) { 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); + rh->task = NULL; + 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); + v4.sin_len = sizeof (v4); #endif - memset (&v6, 0, sizeof(v6)); + memset (&v6, 0, sizeof (v6)); v6.sin6_family = AF_INET6; #if HAVE_SOCKADDR_IN_SIN_LEN - v6.sin6_len = sizeof(v6); + v6.sin6_len = sizeof (v6); #endif v6.sin6_addr = in6addr_loopback; - switch (rh->domain) + 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); + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Finished resolving hostname `%s'.\n", + (const char *) &rh[1]); + GNUNET_free (rh); +} + + +/** + * Now try to reconnect to the resolver service. + * + * @param cls NULL + */ +static void +reconnect_task (void *cls) +{ + struct GNUNET_MQ_MessageHandler handlers[] = { + GNUNET_MQ_hd_var_size (response, + GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE, + struct GNUNET_MessageHeader, + NULL), + GNUNET_MQ_handler_end () + }; + + r_task = NULL; + if (NULL == req_head) + return; /* no work pending */ + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Trying to connect to DNS service\n"); + mq = GNUNET_CLIENT_connect (resolver_cfg, + "resolver", + handlers, + &mq_error_handler, + NULL); + if (NULL == mq) + { + 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 (NULL != r_task) + return; + GNUNET_assert (NULL == mq); + if (NULL != (rh = req_head)) + { + switch (rh->was_transmitted) { - case AF_INET: - rh->addr_callback (rh->cls, - (const struct sockaddr*) &v4, - sizeof(v4)); + case GNUNET_NO: + /* nothing more to do */ break; - case AF_INET6: - rh->addr_callback (rh->cls, - (const struct sockaddr*) &v6, - sizeof(v6)); + case GNUNET_YES: + /* disconnected, transmit again! */ + rh->was_transmitted = GNUNET_NO; 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)); + case GNUNET_SYSERR: + /* request was cancelled, remove entirely */ + GNUNET_CONTAINER_DLL_remove (req_head, + req_tail, + rh); + GNUNET_free (rh); + check_disconnect (); break; default: - GNUNET_break (0); + GNUNET_assert (0); break; } - rh->addr_callback (rh->cls, NULL, 0); - GNUNET_free (rh); + } + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Will try to connect to DNS service in %s\n", + GNUNET_STRINGS_relative_time_to_string (backoff, + GNUNET_YES)); + GNUNET_assert (NULL != resolver_cfg); + r_task = GNUNET_SCHEDULER_add_delayed (backoff, + &reconnect_task, + NULL); + backoff = GNUNET_TIME_STD_BACKOFF (backoff); +} + + +/** + * A DNS resolution timed out. Notify the application. + * + * @param cls the `struct GNUNET_RESOLVER_RequestHandle *` + */ +static void +handle_lookup_timeout (void *cls) +{ + struct GNUNET_RESOLVER_RequestHandle *rh = cls; + + rh->task = NULL; + if (GNUNET_NO == rh->direction) + { + LOG (GNUNET_ERROR_TYPE_INFO, + _("Timeout trying to resolve hostname `%s'.\n"), + (const char *) &rh[1]); + if (NULL != rh->addr_callback) + rh->addr_callback (rh->cls, + NULL, + 0); + } + else + { + char buf[INET6_ADDRSTRLEN]; + + LOG (GNUNET_ERROR_TYPE_INFO, + _("Timeout trying to resolve IP address `%s'.\n"), + inet_ntop (rh->af, + (const void *) &rh[1], + buf, + sizeof(buf))); + if (GNUNET_NO == rh->received_response) + { + char *nret; + + nret = no_resolve (rh->af, + &rh[1], + rh->data_len); + if (NULL != rh->name_callback) + rh->name_callback (rh->cls, nret); + GNUNET_free (nret); + } + /* finally, make termination call */ + if (NULL != rh->name_callback) + rh->name_callback (rh->cls, + NULL); + } + rh->was_transmitted = GNUNET_NO; + GNUNET_RESOLVER_request_cancel (rh); + process_requests (); } /** * Convert a string to one or more IP addresses. * - * @param sched scheduler to use - * @param cfg configuration to use * @param hostname the hostname to resolve - * @param domain AF_INET or AF_INET6; use AF_UNSPEC for "any" + * @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 callback_cls closure for @a 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 (struct GNUNET_SCHEDULER_Handle *sched, - const struct GNUNET_CONFIGURATION_Handle *cfg, - const char *hostname, - int domain, +GNUNET_RESOLVER_ip_get (const char *hostname, + int af, struct GNUNET_TIME_Relative timeout, - GNUNET_RESOLVER_AddressCallback callback, - void *callback_cls) + GNUNET_RESOLVER_AddressCallback callback, + void *callback_cls) { - struct GNUNET_CLIENT_Connection *client; - struct GNUNET_RESOLVER_GetMessage *msg; struct GNUNET_RESOLVER_RequestHandle *rh; size_t slen; unsigned int i; struct in_addr v4; struct in6_addr v6; - char buf[GNUNET_SERVER_MAX_MESSAGE_SIZE]; - check_config (cfg); slen = strlen (hostname) + 1; - if (slen + sizeof (struct GNUNET_RESOLVER_GetMessage) > + 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->sched = sched; - rh->domain = domain; + { + GNUNET_break (0); + return NULL; + } + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Trying to resolve hostname `%s'.\n", + hostname); + 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->hostname = (const char*) &rh[1]; + GNUNET_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)) && - ( (domain == AF_INET) || (domain == AF_UNSPEC)) ) || - ( (1 == inet_pton (AF_INET6, - hostname, - &v6)) && - ( (domain == AF_INET6) || (domain == AF_UNSPEC)) ) ) - { - rh->task = GNUNET_SCHEDULER_add_delayed (sched, - GNUNET_NO, - GNUNET_SCHEDULER_PRIORITY_KEEP, - GNUNET_SCHEDULER_NO_TASK, - GNUNET_TIME_UNIT_ZERO, - &numeric_resolution, - rh); - return rh; - } + 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_delayed (sched, - GNUNET_NO, - GNUNET_SCHEDULER_PRIORITY_KEEP, - GNUNET_SCHEDULER_NO_TASK, - GNUNET_TIME_UNIT_ZERO, - &loopback_resolution, - rh); - return rh; - } - - client = GNUNET_CLIENT_connect (sched, "resolver", cfg); - if (client == NULL) - { - GNUNET_free (rh); - return NULL; - } - rh->client = client; - - msg = (struct GNUNET_RESOLVER_GetMessage*) buf; - msg->header.size = - htons (sizeof (struct GNUNET_RESOLVER_GetMessage) + slen); - msg->header.type = htons (GNUNET_MESSAGE_TYPE_RESOLVER_REQUEST); - msg->direction = htonl (GNUNET_NO); - msg->domain = htonl (domain); - memcpy (&msg[1], hostname, slen); - -#if DEBUG_RESOLVER - GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, - _("Resolver requests DNS resolution of hostname `%s'.\n"), - hostname); -#endif - if (GNUNET_OK != - GNUNET_CLIENT_transmit_and_get_response (client, - &msg->header, - timeout, - GNUNET_YES, - &handle_address_response, - rh)) + while (NULL != loopback[i]) + if (0 == strcasecmp (loopback[i++], + hostname)) { - GNUNET_free (rh); - GNUNET_CLIENT_disconnect (client); - return NULL; + rh->task = GNUNET_SCHEDULER_add_now (&loopback_resolution, + rh); + return rh; } + if (GNUNET_OK != check_config ()) + { + GNUNET_free (rh); + return NULL; + } + rh->task = GNUNET_SCHEDULER_add_delayed (timeout, + &handle_lookup_timeout, + rh); + GNUNET_CONTAINER_DLL_insert_tail (req_head, + req_tail, + rh); + rh->was_queued = GNUNET_YES; + if (NULL != s_task) + { + GNUNET_SCHEDULER_cancel (s_task); + s_task = NULL; + } + process_requests (); return rh; } -/** - * Process response with a hostname for a reverse DNS lookup. - * - * @param cls our "struct GNUNET_RESOLVER_RequestHandle" context - * @param msg message with the hostname, NULL on error - */ -static void -handle_hostname_response (void *cls, - const struct GNUNET_MessageHeader *msg) -{ - struct GNUNET_RESOLVER_RequestHandle *rh = cls; - uint16_t size; - const char *hostname; - - if (msg == NULL) - { - GNUNET_log (GNUNET_ERROR_TYPE_INFO, - _("Timeout trying to resolve IP address.\n")); - rh->name_callback (rh->cls, NULL); - GNUNET_CLIENT_disconnect (rh->client); - GNUNET_free (rh); - return; - } - size = ntohs (msg->size); - if (size == sizeof (struct GNUNET_MessageHeader)) - { -#if DEBUG_RESOLVER - GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, - _("Received end message resolving IP address.\n")); -#endif - rh->name_callback (rh->cls, NULL); - GNUNET_CLIENT_disconnect (rh->client); - GNUNET_free (rh); - return; - } - hostname = (const char *) &msg[1]; - if (hostname[size - sizeof (struct GNUNET_MessageHeader) - 1] != '\0') - { - GNUNET_break (0); - rh->name_callback (rh->cls, NULL); - GNUNET_CLIENT_disconnect (rh->client); - GNUNET_free (rh); - return; - } -#if DEBUG_RESOLVER - GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, - _("Resolver returns `%s'.\n"), hostname); -#endif - rh->name_callback (rh->cls, hostname); - GNUNET_CLIENT_receive (rh->client, - &handle_hostname_response, - rh, - GNUNET_TIME_absolute_get_remaining (rh->timeout)); -} - - - /** * We've been asked to convert an address to a string without - * a reverse lookup. Do it. + * a reverse lookup, either because the client asked for it + * or because the DNS lookup hit a timeout. Do the numeric + * conversion and invoke the callback. * - * @param cls struct GNUNET_RESOLVER_RequestHandle for the request - * @param tc unused scheduler context + * @param cls `struct GNUNET_RESOLVER_RequestHandle` for the request */ static void -numeric_reverse (void *cls, - const struct GNUNET_SCHEDULER_TaskContext *tc) +numeric_reverse (void *cls) { struct GNUNET_RESOLVER_RequestHandle *rh = cls; char *result; - result = no_resolve ((const struct sockaddr*) &rh[1], - rh->salen); -#if DEBUG_RESOLVER - GNUNET_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); + rh->task = NULL; + result = no_resolve (rh->af, + &rh[1], + rh->data_len); + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Resolver returns `%s'.\n", + result); + if (NULL != result) + { + rh->name_callback (rh->cls, + result); + GNUNET_free (result); + } + rh->name_callback (rh->cls, + NULL); + if (NULL != rh->task) + { + GNUNET_SCHEDULER_cancel (rh->task); + rh->task = NULL; + } GNUNET_free (rh); } - /** * Get an IP address as a string. * - * @param sched scheduler to use - * @param cfg configuration to use * @param sa host address - * @param salen length of host address - * @param do_resolve use GNUNET_NO to return numeric hostname + * @param salen length of host address in @a sa + * @param do_resolve use #GNUNET_NO to return numeric hostname * @param timeout how long to try resolving * @param callback function to call with hostnames - * @param cls closure for callback + * last callback is NULL when finished + * @param cls closure for @a callback * @return handle that can be used to cancel the request */ struct GNUNET_RESOLVER_RequestHandle * -GNUNET_RESOLVER_hostname_get (struct GNUNET_SCHEDULER_Handle *sched, - const struct GNUNET_CONFIGURATION_Handle *cfg, - const struct sockaddr *sa, +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_CLIENT_Connection *client; - struct GNUNET_RESOLVER_GetMessage *msg; struct GNUNET_RESOLVER_RequestHandle *rh; - char buf[GNUNET_SERVER_MAX_MESSAGE_SIZE]; + size_t ip_len; + const void *ip; - check_config (cfg); + if (GNUNET_OK != check_config ()) + { + LOG (GNUNET_ERROR_TYPE_ERROR, + _("Resolver not configured correctly.\n")); + return NULL; + } + + switch (sa->sa_family) + { + case AF_INET: + GNUNET_assert (salen == sizeof (struct sockaddr_in)); + ip_len = sizeof (struct in_addr); + ip = &((const struct sockaddr_in*)sa)->sin_addr; + break; + case AF_INET6: + GNUNET_assert (salen == sizeof (struct sockaddr_in6)); + 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); - rh->sched = sched; - rh->salen = salen; - memcpy (&rh[1], sa, salen); - + GNUNET_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; + } + rh->task = GNUNET_SCHEDULER_add_delayed (timeout, + &handle_lookup_timeout, + rh); + GNUNET_CONTAINER_DLL_insert_tail (req_head, + req_tail, + rh); + rh->was_queued = GNUNET_YES; + if (NULL != s_task) + { + GNUNET_SCHEDULER_cancel (s_task); + s_task = NULL; + } + process_requests (); + return rh; +} + + +/** + * Get local fully qualified af name + * + * @return fqdn + */ +char * +GNUNET_RESOLVER_local_fqdn_get () +{ + 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; + } + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Resolving our FQDN `%s'\n", + hostname); +#if HAVE_GETADDRINFO + { + struct addrinfo *ai; + int ret; + char *rval; + + if (0 != (ret = getaddrinfo (hostname, NULL, NULL, &ai))) { - rh->task = GNUNET_SCHEDULER_add_delayed (sched, - GNUNET_NO, - GNUNET_SCHEDULER_PRIORITY_KEEP, - GNUNET_SCHEDULER_NO_TASK, - GNUNET_TIME_UNIT_ZERO, - &numeric_reverse, - rh); - return rh; - } - if (salen + sizeof (struct GNUNET_RESOLVER_GetMessage) > - GNUNET_SERVER_MAX_MESSAGE_SIZE) - { - GNUNET_break (0); - GNUNET_free (rh); - return NULL; - } - client = GNUNET_CLIENT_connect (sched, "resolver", cfg); - if (client == NULL) - { - GNUNET_free (rh); + LOG (GNUNET_ERROR_TYPE_ERROR, + _("Could not resolve our FQDN: %s\n"), + gai_strerror (ret)); return NULL; } - rh->client = client; - - msg = (struct GNUNET_RESOLVER_GetMessage*) buf; - msg->header.size = - htons (sizeof (struct GNUNET_RESOLVER_GetMessage) + salen); - msg->header.type = htons (GNUNET_MESSAGE_TYPE_RESOLVER_REQUEST); - msg->direction = htonl (GNUNET_YES); - msg->domain = htonl (sa->sa_family); - memcpy (&msg[1], sa, salen); -#if DEBUG_RESOLVER - GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, - _("Resolver requests DNS resolution of IP address.\n")); + if (NULL != ai->ai_canonname) + rval = GNUNET_strdup (ai->ai_canonname); + else + rval = GNUNET_strdup (hostname); + freeaddrinfo (ai); + return rval; + } +#elif HAVE_GETHOSTBYNAME2 + { + struct hostent *host; + + host = gethostbyname2 (hostname, AF_INET); + if (NULL == host) + host = gethostbyname2 (hostname, AF_INET6); + 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); + } +#elif HAVE_GETHOSTBYNAME + { + struct hostent *host; + + 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); + } +#else + /* fallback: just hope name is already FQDN */ + return GNUNET_strdup (hostname); #endif - if (GNUNET_OK != - GNUNET_CLIENT_transmit_and_get_response (client, - &msg->header, - timeout, - GNUNET_YES, - &handle_hostname_response, - rh)) - { - GNUNET_CLIENT_disconnect (client); - GNUNET_free (rh); - return NULL; - } - return rh; } /** - * Perform a reverse DNS lookup. + * Looking our own hostname. * - * @param sched scheduler to use - * @param cfg configuration to use - * @param domain AF_INET or AF_INET6; use AF_UNSPEC for "any" - * @param callback function to call with addresses - * @param cls closure for callback + * @param af AF_INET or AF_INET6; use AF_UNSPEC for "any" * @param timeout how long to try resolving + * @param callback function to call with addresses + * @param cls closure for @a callback * @return handle that can be used to cancel the request, NULL on error */ struct GNUNET_RESOLVER_RequestHandle * -GNUNET_RESOLVER_hostname_resolve (struct GNUNET_SCHEDULER_Handle *sched, - const struct GNUNET_CONFIGURATION_Handle *cfg, - int domain, +GNUNET_RESOLVER_hostname_resolve (int af, struct GNUNET_TIME_Relative timeout, GNUNET_RESOLVER_AddressCallback callback, void *cls) { - char hostname[MAX_HOSTNAME]; + char hostname[GNUNET_OS_get_hostname_max_length () + 1]; - check_config (cfg); if (0 != gethostname (hostname, sizeof (hostname) - 1)) - { - GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR | - GNUNET_ERROR_TYPE_BULK, "gethostname"); - return NULL; - } -#if DEBUG_RESOLVER - GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, - _("Resolving our hostname `%s'\n"), hostname); -#endif - return GNUNET_RESOLVER_ip_get (sched, - cfg, hostname, domain, timeout, callback, cls); + { + LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK, + "gethostname"); + return NULL; + } + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Resolving our hostname `%s'\n", + hostname); + return GNUNET_RESOLVER_ip_get (hostname, + af, + timeout, + callback, + cls); } @@ -752,19 +1171,34 @@ GNUNET_RESOLVER_hostname_resolve (struct GNUNET_SCHEDULER_Handle *sched, * been completed (i.e, the callback has been called to * signal timeout or the final result). * - * @param h handle of request to cancel + * @param rh handle of request to cancel */ void -GNUNET_RESOLVER_request_cancel (struct GNUNET_RESOLVER_RequestHandle *h) +GNUNET_RESOLVER_request_cancel (struct GNUNET_RESOLVER_RequestHandle *rh) { - if (h->client != NULL) - GNUNET_CLIENT_disconnect (h->client); - if (h->task != GNUNET_SCHEDULER_NO_TASK) - GNUNET_SCHEDULER_cancel (h->sched, - h->task); - GNUNET_free (h); + if (GNUNET_NO == rh->direction) + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Asked to cancel request to resolve hostname `%s'.\n", + (const char *) &rh[1]); + if (NULL != rh->task) + { + GNUNET_SCHEDULER_cancel (rh->task); + rh->task = NULL; + } + if (GNUNET_NO == rh->was_transmitted) + { + if (GNUNET_YES == rh->was_queued) + GNUNET_CONTAINER_DLL_remove (req_head, + req_tail, + rh); + GNUNET_free (rh); + check_disconnect (); + return; + } + GNUNET_assert (GNUNET_YES == rh->was_transmitted); + rh->was_transmitted = GNUNET_SYSERR; /* mark as cancelled */ + check_disconnect (); } - /* end of resolver_api.c */