X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=src%2Futil%2Fresolver_api.c;h=4261f495c2a72e7aff2ca3a2225829ffd730d94a;hb=8a3016481ba6aeb36de3950a56e641dda53ca544;hp=cbd8392bfff8b212061ed54ff745752c96b808e0;hpb=dedd5548c1fa90f04080389d0826e0e8d3c0ad8c;p=oweals%2Fgnunet.git diff --git a/src/util/resolver_api.c b/src/util/resolver_api.c index cbd8392bf..4261f495c 100644 --- a/src/util/resolver_api.c +++ b/src/util/resolver_api.c @@ -25,53 +25,137 @@ */ #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" +/** + * 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 *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; /** - * FIXME. + * Tail of DLL of requests. + */ +static struct GNUNET_RESOLVER_RequestHandle *req_tail; + +/** + * How long should we wait to reconnect? */ -struct GetAddressContext +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 { /** - * FIXME. + * Next entry in DLL of requests. */ - GNUNET_RESOLVER_AddressCallback callback; + struct GNUNET_RESOLVER_RequestHandle *next; /** - * Closure for "callback". + * Previous entry in DLL of requests. */ - void *cls; + struct GNUNET_RESOLVER_RequestHandle *prev; /** - * FIXME. + * Callback if this is an name resolution request, + * otherwise NULL. */ - struct GNUNET_RESOLVER_GetMessage *msg; + GNUNET_RESOLVER_AddressCallback addr_callback; /** - * FIXME. + * Callback if this is a reverse lookup request, + * otherwise NULL. */ - struct GNUNET_CLIENT_Connection *client; + GNUNET_RESOLVER_HostnameCallback name_callback; /** - * FIXME. + * 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; -/** - * Possible hostnames for "loopback". - */ -static const char *loopback[] = { - "localhost", - "ip6-localnet", - NULL + /** + * Desired address family. + */ + int domain; + + /** + * Has this request been transmitted to the service? + */ + 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; + + /** + * Length of the data that follows this struct. + */ + size_t data_len; }; @@ -84,44 +168,93 @@ check_config (const struct GNUNET_CONFIGURATION_Handle *cfg) { char *hostname; unsigned int i; - struct in_addr v4; - struct in6_addr v6; + 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 (cfg, - "resolver", - "HOSTNAME", - &hostname)) + "resolver", + "HOSTNAME", &hostname)) { GNUNET_log (GNUNET_ERROR_TYPE_ERROR, - _("Must specify `%s' for `%s' in configuration!\n"), - "HOSTNAME", - "resolver"); + _("Must specify `%s' for `%s' in configuration!\n"), + "HOSTNAME", "resolver"); GNUNET_assert (0); } - if ( (0 == inet_pton (AF_INET, - hostname, - &v4)) || - (0 == inet_pton (AF_INET6, - hostname, - &v6)) ) + 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 == strcmp (loopback[i++], hostname)) + if (0 == strcasecmp (loopback[i++], hostname)) { - GNUNET_free (hostname); - return; + GNUNET_free (hostname); + return; } GNUNET_log (GNUNET_ERROR_TYPE_ERROR, - _("Must specify `%s' for `%s' in configuration!\n"), - "localhost", - "resolver"); - GNUNET_free (hostname); - GNUNET_assert (0); + _ + ("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 c configuration to use + */ +void +GNUNET_RESOLVER_connect (const struct GNUNET_CONFIGURATION_Handle *c) +{ + check_config (c); + cfg = c; +} + + +/** + * 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 + GNUNET_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; + } } @@ -146,17 +279,27 @@ no_resolve (const struct sockaddr *sa, socklen_t salen) case AF_INET: if (salen != sizeof (struct sockaddr_in)) return NULL; - inet_ntop (AF_INET, - &((struct sockaddr_in *) sa)->sin_addr, - inet4, INET_ADDRSTRLEN); + if (NULL == + inet_ntop (AF_INET, + &((struct sockaddr_in *) sa)->sin_addr, + inet4, INET_ADDRSTRLEN)) + { + GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "inet_ntop"); + return NULL; + } 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); + if (NULL == + inet_ntop (AF_INET6, + &((struct sockaddr_in6 *) sa)->sin6_addr, + inet6, INET6_ADDRSTRLEN)) + { + GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "inet_ntop"); + return NULL; + } ret = GNUNET_strdup (inet6); break; default: @@ -168,520 +311,656 @@ no_resolve (const struct sockaddr *sa, socklen_t salen) /** - * FIXME + * Adjust exponential back-off and reconnect to the service. + */ +static void +reconnect (); + + +/** + * Process pending requests to the resolver. * - * @param cls FIXME - * @param msg FIXME + * @param h handle to the resolver */ static void -handle_address_response (void *cls, const struct GNUNET_MessageHeader *msg) +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 GetAddressContext *gac = cls; + struct GNUNET_RESOLVER_RequestHandle *rh = cls; uint16_t size; + const char *hostname; const struct sockaddr *sa; socklen_t salen; - +#if DEBUG_RESOLVER + GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, + "Receiving response from DNS service\n"); +#endif if (msg == NULL) { - GNUNET_log (GNUNET_ERROR_TYPE_INFO, - _("Timeout trying to resolve hostname.\n")); - gac->callback (gac->cls, NULL, 0); - GNUNET_CLIENT_disconnect (gac->client); - GNUNET_free (gac); + if (NULL != rh->name_callback) + GNUNET_log (GNUNET_ERROR_TYPE_INFO, + _("Timeout trying to resolve IP address `%s'.\n"), + GNUNET_a2s ((const void*) &rh[1], rh->data_len)); + else + GNUNET_log (GNUNET_ERROR_TYPE_INFO, + _("Timeout trying to resolve hostname `%s'.\n"), + (const char *) &rh[1]); + 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); + GNUNET_CLIENT_disconnect (client, GNUNET_NO); + client = NULL; + reconnect (); return; } if (GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE != ntohs (msg->type)) { GNUNET_break (0); - gac->callback (gac->cls, NULL, 0); - GNUNET_CLIENT_disconnect (gac->client); - GNUNET_free (gac); + GNUNET_CLIENT_disconnect (client, GNUNET_NO); + client = NULL; + reconnect (); return; } - size = ntohs (msg->size); if (size == sizeof (struct GNUNET_MessageHeader)) { + 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; + } + if (NULL != rh->name_callback) + { + 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 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, - _("Received end message resolving hostname.\n")); + _("Resolver returns `%s' for IP `%s'.\n"), + hostname, + GNUNET_a2s ((const void*) &rh[1], rh->data_len)); #endif - gac->callback (gac->cls, NULL, 0); - GNUNET_CLIENT_disconnect (gac->client); - GNUNET_free (gac); - return; + if (rh->was_transmitted != GNUNET_SYSERR) + rh->name_callback (rh->cls, hostname); + GNUNET_CLIENT_receive (client, + &handle_response, + rh, + GNUNET_TIME_absolute_get_remaining (rh->timeout)); } - sa = (const struct sockaddr *) &msg[1]; - salen = size - sizeof (struct GNUNET_MessageHeader); - if (salen < sizeof (struct sockaddr)) + if (NULL != rh->addr_callback) { - GNUNET_break (0); - gac->callback (gac->cls, NULL, 0); - GNUNET_CLIENT_disconnect (gac->client); - GNUNET_free (gac); - return; - } + sa = (const struct sockaddr *) &msg[1]; + salen = size - sizeof (struct GNUNET_MessageHeader); + if (salen < sizeof (struct sockaddr)) + { + 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; + } #if DEBUG_RESOLVER - { - char *ips = no_resolve (sa, salen); - GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, _("Resolver returns `%s'.\n"), ips); - GNUNET_free (ips); - } + { + char *ips = no_resolve (sa, salen); + GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, + "Resolver returns `%s' for `%s'.\n", + ips, + (const char*) &rh[1]); + GNUNET_free (ips); + } #endif - gac->callback (gac->cls, sa, salen); - GNUNET_CLIENT_receive (gac->client, - &handle_address_response, - gac, - GNUNET_TIME_absolute_get_remaining (gac->timeout)); + rh->addr_callback (rh->cls, sa, salen); + GNUNET_CLIENT_receive (client, + &handle_response, + rh, + GNUNET_TIME_absolute_get_remaining (rh->timeout)); + } } /** - * FIXME + * 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 FIXME - * @param size number of bytes available in buf - * @param buf target buffer, NULL on error - * @return number of bytes written to buf + * @param cls struct GNUNET_RESOLVER_RequestHandle for the request + * @param tc unused scheduler context */ -static size_t -transmit_get_ip (void *cls, size_t size, void *buf) +static void +numeric_resolution (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { - struct GetAddressContext *actx = cls; - uint16_t ms; + struct GNUNET_RESOLVER_RequestHandle *rh = cls; + struct sockaddr_in v4; + struct sockaddr_in6 v6; + const char *hostname; - if (buf == NULL) + 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->domain == AF_UNSPEC) || (rh->domain == AF_INET)) && + (1 == inet_pton (AF_INET, hostname, &v4.sin_addr))) + { + rh->addr_callback (rh->cls, (const struct sockaddr *) &v4, sizeof (v4)); + if ((rh->domain == 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->domain == AF_UNSPEC) || (rh->domain == AF_INET6)) && + (1 == inet_pton (AF_INET6, hostname, &v6.sin6_addr))) { - /* timeout / error */ - GNUNET_free (actx->msg); - actx->callback (actx->cls, NULL, 0); - GNUNET_CLIENT_disconnect (actx->client); - GNUNET_free (actx); - return 0; + rh->addr_callback (rh->cls, (const struct sockaddr *) &v6, sizeof (v6)); + rh->addr_callback (rh->cls, NULL, 0); + GNUNET_free (rh); + return; } - ms = ntohs (actx->msg->header.size); - GNUNET_assert (size >= ms); - memcpy (buf, actx->msg, ms); - GNUNET_free (actx->msg); - actx->msg = NULL; - GNUNET_CLIENT_receive (actx->client, - &handle_address_response, - actx, - GNUNET_TIME_absolute_get_remaining (actx->timeout)); - return ms; + /* why are we here? this task should not have been scheduled! */ + GNUNET_assert (0); + GNUNET_free (rh); } - /** - * Convert a string to one or more IP addresses. + * 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 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 callback function to call with addresses - * @param callback_cls closure for callback - * @param timeout how long to try resolving + * @param cls struct GNUNET_RESOLVER_RequestHandle for the request + * @param tc unused scheduler context */ -void -GNUNET_RESOLVER_ip_get (struct GNUNET_SCHEDULER_Handle *sched, - const struct GNUNET_CONFIGURATION_Handle *cfg, - const char *hostname, - int domain, - struct GNUNET_TIME_Relative timeout, - GNUNET_RESOLVER_AddressCallback callback, - void *callback_cls) +static void +loopback_resolution (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { - struct GNUNET_CLIENT_Connection *client; - struct GNUNET_RESOLVER_GetMessage *msg; - struct GetAddressContext *actx; - size_t slen; - unsigned int i; + 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); + 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 - /* first, check if this is a numeric address */ - if ( ( (domain == AF_UNSPEC) || (domain == AF_INET) ) && - (0 == inet_pton (AF_INET, - hostname, - &v4.sin_addr)) ) + v6.sin6_addr = in6addr_loopback; + switch (rh->domain) { - callback (callback_cls, - (const struct sockaddr*) &v4, - sizeof(v4)); - if ( (domain == AF_UNSPEC) && - (0 == inet_pton (AF_INET6, - hostname, - &v6.sin6_addr)) ) - { - /* this can happen on some systems IF "hostname" is "localhost" */ - callback (callback_cls, - (const struct sockaddr*) &v6, - sizeof(v6)); - } - callback (callback_cls, NULL, 0); - return; + 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; } - if ( ( (domain == AF_UNSPEC) ||(domain == AF_INET) ) && - (0 == inet_pton (AF_INET6, - hostname, - &v6.sin6_addr)) ) + 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. + * + * @param h handle 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) { - callback (callback_cls, - (const struct sockaddr*) &v6, - sizeof(v6)); - callback (callback_cls, NULL, 0); + reconnect (); return; } - check_config (cfg); - /* then, check if this is a loopback address */ - i = 0; - while (loopback[i] != NULL) - if (0 == strcmp (loopback[i++], hostname)) - { - v4.sin_addr.s_addr = htonl (INADDR_LOOPBACK); - v6.sin6_addr = in6addr_loopback; - switch (domain) - { - case AF_INET: - callback (callback_cls, - (const struct sockaddr*) &v4, - sizeof(v4)); - break; - case AF_INET6: - callback (callback_cls, - (const struct sockaddr*) &v6, - sizeof(v6)); - break; - case AF_UNSPEC: - callback (callback_cls, - (const struct sockaddr*) &v6, - sizeof(v6)); - callback (callback_cls, - (const struct sockaddr*) &v4, - sizeof(v4)); - break; - } - callback (callback_cls, NULL, 0); - return; - } - slen = strlen (hostname) + 1; - if (slen + sizeof (struct GNUNET_RESOLVER_GetMessage) > - GNUNET_SERVER_MAX_MESSAGE_SIZE) + rh = req_head; + if (NULL == rh) { - GNUNET_break (0); - callback (callback_cls, NULL, 0); - return; + /* 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; } - client = GNUNET_CLIENT_connect (sched, "resolver", cfg); - if (client == NULL) + 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->domain = htonl (rh->domain); + memcpy (&msg[1], &rh[1], rh->data_len); +#if DEBUG_RESOLVER + GNUNET_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)) { - callback (callback_cls, NULL, 0); + GNUNET_CLIENT_disconnect (client, GNUNET_NO); + client = NULL; + reconnect (); return; } - msg = GNUNET_malloc (sizeof (struct GNUNET_RESOLVER_GetMessage) + slen); - 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); - actx = GNUNET_malloc (sizeof (struct GetAddressContext)); - actx->callback = callback; - actx->cls = callback_cls; - actx->client = client; - actx->timeout = GNUNET_TIME_relative_to_absolute (timeout); - actx->msg = msg; + 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 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, - _("Resolver requests DNS resolution of hostname `%s'.\n"), - hostname); + "Trying to connect to DNS service\n"); #endif - if (NULL == - GNUNET_CLIENT_notify_transmit_ready (client, - slen + - sizeof (struct - GNUNET_RESOLVER_GetMessage), - timeout, &transmit_get_ip, actx)) + client = GNUNET_CLIENT_connect ("resolver", cfg); + if (NULL == client) { - GNUNET_free (msg); - GNUNET_free (actx); - callback (callback_cls, NULL, 0); - GNUNET_CLIENT_disconnect (client); + GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, + "Failed to connect, will try again later\n"); + reconnect (); return; } + process_requests (); } /** - * FIXME. + * Adjust exponential back-off and reconnect to the service. */ -struct GetHostnameContext +static void +reconnect () { + struct GNUNET_RESOLVER_RequestHandle *rh; - /** - * FIXME. - */ - GNUNET_RESOLVER_HostnameCallback callback; - - /** - * FIXME. - */ - void *cls; - - /** - * FIXME. - */ - struct GNUNET_RESOLVER_GetMessage *msg; - - /** - * FIXME. - */ - struct GNUNET_CLIENT_Connection *client; - - /** - * FIXME. - */ - struct GNUNET_TIME_Absolute timeout; -}; + 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 + GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, + "Will try to connect to DNS service in %llu ms\n", + (unsigned long long) backoff.rel_value); +#endif + r_task = GNUNET_SCHEDULER_add_delayed (backoff, + &reconnect_task, + NULL); + backoff = GNUNET_TIME_relative_max (GNUNET_TIME_UNIT_SECONDS, + GNUNET_TIME_relative_multiply (backoff, 2)); +} /** - * FIXME. + * Convert a string to one or more IP addresses. * - * @param cls FIXME - * @param msg FIXME + * @param hostname the hostname to resolve + * @param domain 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 */ -static void -handle_hostname_response (void *cls, const struct GNUNET_MessageHeader *msg) +struct GNUNET_RESOLVER_RequestHandle * +GNUNET_RESOLVER_ip_get (const char *hostname, + int domain, + struct GNUNET_TIME_Relative timeout, + GNUNET_RESOLVER_AddressCallback callback, + void *callback_cls) { - struct GetHostnameContext *ghc = cls; - uint16_t size; - const char *hostname; + struct GNUNET_RESOLVER_RequestHandle *rh; + size_t slen; + unsigned int i; + struct in_addr v4; + struct in6_addr v6; - if (msg == NULL) + slen = strlen (hostname) + 1; + if (slen + sizeof (struct GNUNET_RESOLVER_GetMessage) >= GNUNET_SERVER_MAX_MESSAGE_SIZE) { - GNUNET_log (GNUNET_ERROR_TYPE_INFO, - _("Timeout trying to resolve IP address.\n")); - ghc->callback (ghc->cls, NULL); - GNUNET_CLIENT_disconnect (ghc->client); - GNUNET_free (ghc); - return; + GNUNET_break (0); + return NULL; } - size = ntohs (msg->size); - if (size == sizeof (struct GNUNET_MessageHeader)) + rh = GNUNET_malloc (sizeof (struct GNUNET_RESOLVER_RequestHandle) + slen); + rh->domain = domain; + 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)) && + ((domain == AF_INET) || (domain == AF_UNSPEC))) || + ((1 == inet_pton (AF_INET6, + hostname, + &v6)) && + ((domain == AF_INET6) || (domain == AF_UNSPEC)))) { -#if DEBUG_RESOLVER - GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, - _("Received end message resolving IP address.\n")); -#endif - ghc->callback (ghc->cls, NULL); - GNUNET_CLIENT_disconnect (ghc->client); - GNUNET_free (ghc); - return; + rh->task = GNUNET_SCHEDULER_add_now (&numeric_resolution, rh); + return rh; } - hostname = (const char *) &msg[1]; - if (hostname[size - sizeof (struct GNUNET_MessageHeader) - 1] != '\0') + /* 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_break (0); - ghc->callback (ghc->cls, NULL); - GNUNET_CLIENT_disconnect (ghc->client); - GNUNET_free (ghc); - return; + GNUNET_SCHEDULER_cancel (s_task); + s_task = GNUNET_SCHEDULER_NO_TASK; } -#if DEBUG_RESOLVER - GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, - _("Resolver returns `%s'.\n"), hostname); -#endif - ghc->callback (ghc->cls, hostname); - GNUNET_CLIENT_receive (ghc->client, - &handle_hostname_response, - ghc, - GNUNET_TIME_absolute_get_remaining (ghc->timeout)); + process_requests (); + return rh; } /** - * FIXME + * We've been asked to convert an address to a string without + * a reverse lookup. Do it. * - * @param cls FIXME - * @param size number of bytes available in buf - * @param buf target buffer, NULL on error - * @return number of bytes written to buf + * @param cls struct GNUNET_RESOLVER_RequestHandle for the request + * @param tc unused scheduler context */ -static size_t -transmit_get_hostname (void *cls, size_t size, void *buf) +static void +numeric_reverse (void *cls, + const struct GNUNET_SCHEDULER_TaskContext *tc) { - struct GetHostnameContext *hctx = cls; - uint16_t msize; + struct GNUNET_RESOLVER_RequestHandle *rh = cls; + char *result; - if (buf == NULL) + result = no_resolve ((const struct sockaddr *) &rh[1], rh->data_len); +#if DEBUG_RESOLVER + GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, _("Resolver returns `%s'.\n"), result); +#endif + if (result != NULL) { - GNUNET_free (hctx->msg); - hctx->callback (hctx->cls, NULL); - GNUNET_CLIENT_disconnect (hctx->client); - GNUNET_free (hctx); - return 0; + rh->name_callback (rh->cls, result); + GNUNET_free (result); } - msize = ntohs (hctx->msg->header.size); - GNUNET_assert (size >= msize); - memcpy (buf, hctx->msg, msize); - GNUNET_free (hctx->msg); - hctx->msg = NULL; - GNUNET_CLIENT_receive (hctx->client, - &handle_hostname_response, - hctx, - GNUNET_TIME_absolute_get_remaining (hctx->timeout)); - return msize; + rh->name_callback (rh->cls, 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 timeout how long to try resolving * @param callback function to call with hostnames * @param cls closure for callback + * @return handle that can be used to cancel the request */ -void -GNUNET_RESOLVER_hostname_get (struct GNUNET_SCHEDULER_Handle *sched, - const struct GNUNET_CONFIGURATION_Handle *cfg, - const struct sockaddr *sa, +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) { - char *result; - struct GNUNET_CLIENT_Connection *client; - struct GNUNET_RESOLVER_GetMessage *msg; - struct GetHostnameContext *hctx; + struct GNUNET_RESOLVER_RequestHandle *rh; check_config (cfg); + rh = GNUNET_malloc (sizeof (struct GNUNET_RESOLVER_RequestHandle) + salen); + rh->name_callback = callback; + rh->cls = cls; + rh->timeout = GNUNET_TIME_relative_to_absolute (timeout); + memcpy (&rh[1], sa, salen); + rh->data_len = salen; + rh->direction = GNUNET_YES; if (GNUNET_NO == do_resolve) { - result = no_resolve (sa, salen); -#if DEBUG_RESOLVER - GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, - _("Resolver returns `%s'.\n"), result); -#endif - callback (cls, result); - if (result != NULL) - { - GNUNET_free (result); - callback (cls, NULL); - } - return; + rh->task = GNUNET_SCHEDULER_add_now (&numeric_reverse, rh); + return rh; } - if (salen + sizeof (struct GNUNET_RESOLVER_GetMessage) > - GNUNET_SERVER_MAX_MESSAGE_SIZE) + if (salen + sizeof (struct GNUNET_RESOLVER_GetMessage) >= GNUNET_SERVER_MAX_MESSAGE_SIZE) { GNUNET_break (0); - callback (cls, NULL); - return; + GNUNET_free (rh); + return NULL; } - client = GNUNET_CLIENT_connect (sched, "resolver", cfg); - if (client == NULL) + GNUNET_CONTAINER_DLL_insert_tail (req_head, + req_tail, + rh); + rh->was_queued = GNUNET_YES; + if (s_task != GNUNET_SCHEDULER_NO_TASK) { - callback (cls, NULL); - return; + GNUNET_SCHEDULER_cancel (s_task); + s_task = GNUNET_SCHEDULER_NO_TASK; + } + process_requests (); + return rh; +} + + +/** + * Get local fully qualified domain 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)) + { + GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR | + GNUNET_ERROR_TYPE_BULK, "gethostname"); + return NULL; } - msg = GNUNET_malloc (sizeof (struct GNUNET_RESOLVER_GetMessage) + salen); - 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")); + _("Resolving our FQDN `%s'\n"), hostname); #endif - hctx = GNUNET_malloc (sizeof (struct GetHostnameContext)); - hctx->callback = callback; - hctx->cls = cls; - hctx->client = client; - hctx->timeout = GNUNET_TIME_relative_to_absolute (timeout); - hctx->msg = msg; - if (NULL == - GNUNET_CLIENT_notify_transmit_ready (client, - sizeof (struct - GNUNET_RESOLVER_GetMessage) - + salen, timeout, - &transmit_get_hostname, hctx)) + host = gethostbyname (hostname); + if (NULL == host) { - GNUNET_free (msg); - callback (cls, NULL); - GNUNET_CLIENT_disconnect (client); - GNUNET_free (hctx); + GNUNET_log (GNUNET_ERROR_TYPE_ERROR, + _("Could not resolve our FQDN : %s\n"), + hstrerror (h_errno)); + return NULL; } + return GNUNET_strdup (host->h_name); } -/** - * Maximum supported length of hostname - */ -#define MAX_HOSTNAME 1024 - /** - * Resolve our hostname to an IP address. + * 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 timeout how long to try resolving + * @return handle that can be used to cancel the request, NULL on error */ -void -GNUNET_RESOLVER_hostname_resolve (struct GNUNET_SCHEDULER_Handle *sched, - const struct GNUNET_CONFIGURATION_Handle *cfg, - int domain, +struct GNUNET_RESOLVER_RequestHandle * +GNUNET_RESOLVER_hostname_resolve (int domain, 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"); - callback (cls, NULL, 0); - return; + return NULL; } #if DEBUG_RESOLVER GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, _("Resolving our hostname `%s'\n"), hostname); #endif - GNUNET_RESOLVER_ip_get (sched, - cfg, hostname, domain, timeout, callback, cls); + return GNUNET_RESOLVER_ip_get (hostname, + domain, + 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 */