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Diffstat (limited to 'src/util/client.c')
| -rw-r--r-- | src/util/client.c | 1216 |
1 files changed, 1216 insertions, 0 deletions
diff --git a/src/util/client.c b/src/util/client.c new file mode 100644 index 0000000..2f09a90 --- /dev/null +++ b/src/util/client.c @@ -0,0 +1,1216 @@ +/* + This file is part of GNUnet. + (C) 2001, 2002, 2006, 2008, 2009 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/client.c + * @brief code for access to services + * @author Christian Grothoff + * + * Generic TCP code for reliable, record-oriented TCP + * connections between clients and service providers. + */ + +#include "platform.h" +#include "gnunet_common.h" +#include "gnunet_client_lib.h" +#include "gnunet_protocols.h" +#include "gnunet_server_lib.h" +#include "gnunet_scheduler_lib.h" + +#define DEBUG_CLIENT GNUNET_EXTRA_LOGGING + +/** + * How often do we re-try tranmsitting requests before giving up? + * Note that if we succeeded transmitting a request but failed to read + * a response, we do NOT re-try. + */ +#define MAX_ATTEMPTS 50 + +#define LOG(kind,...) GNUNET_log_from (kind, "util",__VA_ARGS__) + +/** + * Handle for a transmission request. + */ +struct GNUNET_CLIENT_TransmitHandle +{ + /** + * Connection state. + */ + struct GNUNET_CLIENT_Connection *sock; + + /** + * Function to call to get the data for transmission. + */ + GNUNET_CONNECTION_TransmitReadyNotify notify; + + /** + * Closure for notify. + */ + void *notify_cls; + + /** + * Handle to the transmission with the underlying + * connection. + */ + struct GNUNET_CONNECTION_TransmitHandle *th; + + /** + * If we are re-trying and are delaying to do so, + * handle to the scheduled task managing the delay. + */ + GNUNET_SCHEDULER_TaskIdentifier reconnect_task; + + /** + * Timeout for the operation overall. + */ + struct GNUNET_TIME_Absolute timeout; + + /** + * Number of bytes requested. + */ + size_t size; + + /** + * Are we allowed to re-try to connect without telling + * the user (of this API) about the connection troubles? + */ + int auto_retry; + + /** + * Number of attempts left for transmitting the request. We may + * fail the first time (say because the service is not yet up), in + * which case (if auto_retry is set) we wait a bit and re-try + * (timeout permitting). + */ + unsigned int attempts_left; + +}; + + +/** + * Context for processing + * "GNUNET_CLIENT_transmit_and_get_response" requests. + */ +struct TransmitGetResponseContext +{ + /** + * Client handle. + */ + struct GNUNET_CLIENT_Connection *sock; + + /** + * Message to transmit; do not free, allocated + * right after this struct. + */ + const struct GNUNET_MessageHeader *hdr; + + /** + * Timeout to use. + */ + struct GNUNET_TIME_Absolute timeout; + + /** + * Function to call when done. + */ + GNUNET_CLIENT_MessageHandler rn; + + /** + * Closure for "rn". + */ + void *rn_cls; +}; + +/** + * Struct to refer to a GNUnet TCP connection. + * This is more than just a socket because if the server + * drops the connection, the client automatically tries + * to reconnect (and for that needs connection information). + */ +struct GNUNET_CLIENT_Connection +{ + + /** + * the socket handle, NULL if not live + */ + struct GNUNET_CONNECTION_Handle *sock; + + /** + * Our configuration. + */ + const struct GNUNET_CONFIGURATION_Handle *cfg; + + /** + * Name of the service we interact with. + */ + char *service_name; + + /** + * Context of a transmit_and_get_response operation, NULL + * if no such operation is pending. + */ + struct TransmitGetResponseContext *tag; + + /** + * Handler for current receiver task. + */ + GNUNET_CLIENT_MessageHandler receiver_handler; + + /** + * Closure for receiver_handler. + */ + void *receiver_handler_cls; + + /** + * Handle for a pending transmission request, NULL if there is + * none pending. + */ + struct GNUNET_CLIENT_TransmitHandle *th; + + /** + * Handler for service test completion (NULL unless in service_test) + */ + GNUNET_SCHEDULER_Task test_cb; + + /** + * Deadline for calling 'test_cb'. + */ + struct GNUNET_TIME_Absolute test_deadline; + + /** + * If we are re-trying and are delaying to do so, + * handle to the scheduled task managing the delay. + */ + GNUNET_SCHEDULER_TaskIdentifier receive_task; + + /** + * Closure for test_cb (NULL unless in service_test) + */ + void *test_cb_cls; + + /** + * Buffer for received message. + */ + char *received_buf; + + /** + * Timeout for receiving a response (absolute time). + */ + struct GNUNET_TIME_Absolute receive_timeout; + + /** + * Current value for our incremental back-off (for + * connect re-tries). + */ + struct GNUNET_TIME_Relative back_off; + + /** + * Number of bytes in received_buf that are valid. + */ + size_t received_pos; + + /** + * Size of received_buf. + */ + unsigned int received_size; + + /** + * Do we have a complete response in received_buf? + */ + int msg_complete; + + /** + * Are we currently busy doing receive-processing? + * GNUNET_YES if so, GNUNET_NO if not. + */ + int in_receive; + + /** + * How often have we tried to connect? + */ + unsigned int attempts; + +}; + + +/** + * Try to connect to the service. + * + * @param service_name name of service to connect to + * @param cfg configuration to use + * @param attempt counter used to alternate between IP and UNIX domain sockets + * @return NULL on error + */ +static struct GNUNET_CONNECTION_Handle * +do_connect (const char *service_name, + const struct GNUNET_CONFIGURATION_Handle *cfg, unsigned int attempt) +{ + struct GNUNET_CONNECTION_Handle *sock; + char *hostname; + char *unixpath; + unsigned long long port; + + sock = NULL; +#if AF_UNIX + if (0 == (attempt % 2)) + { + /* on even rounds, try UNIX */ + unixpath = NULL; + if ((GNUNET_OK == GNUNET_CONFIGURATION_get_value_string (cfg, service_name, "UNIXPATH", &unixpath)) && (0 < strlen (unixpath))) /* We have a non-NULL unixpath, does that mean it's valid? */ + { + sock = GNUNET_CONNECTION_create_from_connect_to_unixpath (cfg, unixpath); + if (sock != NULL) + { +#if DEBUG_CLIENT + LOG (GNUNET_ERROR_TYPE_DEBUG, "Connected to unixpath `%s'!\n", + unixpath); +#endif + GNUNET_free (unixpath); + return sock; + } + } + GNUNET_free_non_null (unixpath); + } +#endif + + if (GNUNET_YES == + GNUNET_CONFIGURATION_have_value (cfg, service_name, "PORT")) + { + if ((GNUNET_OK != + GNUNET_CONFIGURATION_get_value_number (cfg, service_name, "PORT", &port)) + || (port > 65535) || + (GNUNET_OK != + GNUNET_CONFIGURATION_get_value_string (cfg, service_name, "HOSTNAME", + &hostname))) + { + LOG (GNUNET_ERROR_TYPE_WARNING, + _ + ("Could not determine valid hostname and port for service `%s' from configuration.\n"), + service_name); + return NULL; + } + if (0 == strlen (hostname)) + { + GNUNET_free (hostname); + LOG (GNUNET_ERROR_TYPE_WARNING, + _("Need a non-empty hostname for service `%s'.\n"), service_name); + return NULL; + } + } + else + { + /* unspecified means 0 (disabled) */ + port = 0; + hostname = NULL; + } + if (port == 0) + { +#if AF_UNIX + if (0 != (attempt % 2)) + { + /* try UNIX */ + unixpath = NULL; + if ((GNUNET_OK == + GNUNET_CONFIGURATION_get_value_string (cfg, service_name, "UNIXPATH", + &unixpath)) && + (0 < strlen (unixpath))) + { + sock = + GNUNET_CONNECTION_create_from_connect_to_unixpath (cfg, unixpath); + if (sock != NULL) + { + GNUNET_free (unixpath); + GNUNET_free_non_null (hostname); + return sock; + } + } + GNUNET_free_non_null (unixpath); + } +#endif +#if DEBUG_CLIENT + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Port is 0 for service `%s', UNIXPATH did not work, returning NULL!\n", + service_name); +#endif + GNUNET_free_non_null (hostname); + return NULL; + } + + sock = GNUNET_CONNECTION_create_from_connect (cfg, hostname, port); + GNUNET_free (hostname); + return sock; +} + + +/** + * Get a connection with a service. + * + * @param service_name name of the service + * @param cfg configuration to use + * @return NULL on error (service unknown to configuration) + */ +struct GNUNET_CLIENT_Connection * +GNUNET_CLIENT_connect (const char *service_name, + const struct GNUNET_CONFIGURATION_Handle *cfg) +{ + struct GNUNET_CLIENT_Connection *ret; + struct GNUNET_CONNECTION_Handle *sock; + + sock = do_connect (service_name, cfg, 0); + ret = GNUNET_malloc (sizeof (struct GNUNET_CLIENT_Connection)); + ret->attempts = 1; + ret->sock = sock; + ret->service_name = GNUNET_strdup (service_name); + ret->cfg = cfg; + ret->back_off = GNUNET_TIME_UNIT_MILLISECONDS; + return ret; +} + + +/** + * Destroy connection with the service. This will automatically + * cancel any pending "receive" request (however, the handler will + * *NOT* be called, not even with a NULL message). Any pending + * transmission request will also be cancelled UNLESS the callback for + * the transmission request has already been called, in which case the + * transmission 'finish_pending_write' argument determines whether or + * not the write is guaranteed to complete before the socket is fully + * destroyed (unless, of course, there is an error with the server in + * which case the message may still be lost). + * + * @param finish_pending_write should a transmission already passed to the + * handle be completed? + * @param sock handle to the service connection + */ +void +GNUNET_CLIENT_disconnect (struct GNUNET_CLIENT_Connection *sock, + int finish_pending_write) +{ + if (sock->in_receive == GNUNET_YES) + { + GNUNET_CONNECTION_receive_cancel (sock->sock); + sock->in_receive = GNUNET_NO; + } + if (sock->th != NULL) + { + GNUNET_CLIENT_notify_transmit_ready_cancel (sock->th); + sock->th = NULL; + } + if (NULL != sock->sock) + { + GNUNET_CONNECTION_destroy (sock->sock, finish_pending_write); + sock->sock = NULL; + } + if (sock->receive_task != GNUNET_SCHEDULER_NO_TASK) + { + GNUNET_SCHEDULER_cancel (sock->receive_task); + sock->receive_task = GNUNET_SCHEDULER_NO_TASK; + } + if (sock->tag != NULL) + { + GNUNET_free (sock->tag); + sock->tag = NULL; + } + sock->receiver_handler = NULL; + GNUNET_array_grow (sock->received_buf, sock->received_size, 0); + GNUNET_free (sock->service_name); + GNUNET_free (sock); +} + + +/** + * Check if message is complete + */ +static void +check_complete (struct GNUNET_CLIENT_Connection *conn) +{ + if ((conn->received_pos >= sizeof (struct GNUNET_MessageHeader)) && + (conn->received_pos >= + ntohs (((const struct GNUNET_MessageHeader *) conn->received_buf)-> + size))) + conn->msg_complete = GNUNET_YES; +} + + +/** + * Callback function for data received from the network. Note that + * both "available" and "errCode" would be 0 if the read simply timed out. + * + * @param cls closure + * @param buf pointer to received data + * @param available number of bytes availabe in "buf", + * possibly 0 (on errors) + * @param addr address of the sender + * @param addrlen size of addr + * @param errCode value of errno (on errors receiving) + */ +static void +receive_helper (void *cls, const void *buf, size_t available, + const struct sockaddr *addr, socklen_t addrlen, int errCode) +{ + struct GNUNET_CLIENT_Connection *conn = cls; + struct GNUNET_TIME_Relative remaining; + GNUNET_CLIENT_MessageHandler receive_handler; + void *receive_handler_cls; + + GNUNET_assert (conn->msg_complete == GNUNET_NO); + conn->in_receive = GNUNET_NO; + if ((available == 0) || (conn->sock == NULL) || (errCode != 0)) + { + /* signal timeout! */ +#if DEBUG_CLIENT + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Timeout in receive_helper, available %u, conn->sock %s, errCode `%s'\n", + (unsigned int) available, conn->sock == NULL ? "NULL" : "non-NULL", + STRERROR (errCode)); +#endif + if (NULL != (receive_handler = conn->receiver_handler)) + { + receive_handler_cls = conn->receiver_handler_cls; + conn->receiver_handler = NULL; + receive_handler (receive_handler_cls, NULL); + } + return; + } + + /* FIXME: optimize for common fast case where buf contains the + * entire message and we need no copying... */ + + + /* slow path: append to array */ + if (conn->received_size < conn->received_pos + available) + GNUNET_array_grow (conn->received_buf, conn->received_size, + conn->received_pos + available); + memcpy (&conn->received_buf[conn->received_pos], buf, available); + conn->received_pos += available; + check_complete (conn); + /* check for timeout */ + remaining = GNUNET_TIME_absolute_get_remaining (conn->receive_timeout); + if (remaining.rel_value == 0) + { + /* signal timeout! */ + if (NULL != conn->receiver_handler) + conn->receiver_handler (conn->receiver_handler_cls, NULL); + return; + } + /* back to receive -- either for more data or to call callback! */ + GNUNET_CLIENT_receive (conn, conn->receiver_handler, + conn->receiver_handler_cls, remaining); +} + + +/** + * Continuation to call the receive callback. + * + * @param cls our handle to the client connection + * @param tc scheduler context + */ +static void +receive_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) +{ + struct GNUNET_CLIENT_Connection *sock = cls; + GNUNET_CLIENT_MessageHandler handler = sock->receiver_handler; + const struct GNUNET_MessageHeader *cmsg = + (const struct GNUNET_MessageHeader *) sock->received_buf; + void *handler_cls = sock->receiver_handler_cls; + uint16_t msize = ntohs (cmsg->size); + char mbuf[msize]; + struct GNUNET_MessageHeader *msg = (struct GNUNET_MessageHeader *) mbuf; + +#if DEBUG_CLIENT + LOG (GNUNET_ERROR_TYPE_DEBUG, "Received message of type %u and size %u\n", + ntohs (cmsg->type), msize); +#endif + sock->receive_task = GNUNET_SCHEDULER_NO_TASK; + GNUNET_assert (GNUNET_YES == sock->msg_complete); + GNUNET_assert (sock->received_pos >= msize); + memcpy (msg, cmsg, msize); + memmove (sock->received_buf, &sock->received_buf[msize], + sock->received_pos - msize); + sock->received_pos -= msize; + sock->msg_complete = GNUNET_NO; + sock->receiver_handler = NULL; + check_complete (sock); + if (handler != NULL) + handler (handler_cls, msg); +} + + +/** + * Read from the service. + * + * @param sock the service + * @param handler function to call with the message + * @param handler_cls closure for handler + * @param timeout how long to wait until timing out + */ +void +GNUNET_CLIENT_receive (struct GNUNET_CLIENT_Connection *sock, + GNUNET_CLIENT_MessageHandler handler, void *handler_cls, + struct GNUNET_TIME_Relative timeout) +{ + if (sock->sock == NULL) + { + /* already disconnected, fail instantly! */ + GNUNET_break (0); /* this should not happen in well-written code! */ + if (NULL != handler) + handler (handler_cls, NULL); + return; + } + sock->receiver_handler = handler; + sock->receiver_handler_cls = handler_cls; + sock->receive_timeout = GNUNET_TIME_relative_to_absolute (timeout); + if (GNUNET_YES == sock->msg_complete) + { + GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == sock->receive_task); + sock->receive_task = GNUNET_SCHEDULER_add_now (&receive_task, sock); + } + else + { + GNUNET_assert (sock->in_receive == GNUNET_NO); + sock->in_receive = GNUNET_YES; +#if DEBUG_CLIENT + LOG (GNUNET_ERROR_TYPE_DEBUG, "calling GNUNET_CONNECTION_receive\n"); +#endif + GNUNET_CONNECTION_receive (sock->sock, GNUNET_SERVER_MAX_MESSAGE_SIZE - 1, + timeout, &receive_helper, sock); + } +} + + +/** + * Report service unavailable. + */ +static void +service_test_error (GNUNET_SCHEDULER_Task task, void *task_cls) +{ + GNUNET_SCHEDULER_add_continuation (task, task_cls, + GNUNET_SCHEDULER_REASON_TIMEOUT); +} + + +/** + * Receive confirmation from test, service is up. + * + * @param cls closure + * @param msg message received, NULL on timeout or fatal error + */ +static void +confirm_handler (void *cls, const struct GNUNET_MessageHeader *msg) +{ + struct GNUNET_CLIENT_Connection *conn = cls; + + /* We may want to consider looking at the reply in more + * detail in the future, for example, is this the + * correct service? FIXME! */ + if (msg != NULL) + { +#if DEBUG_CLIENT + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Received confirmation that service is running.\n"); +#endif + GNUNET_SCHEDULER_add_continuation (conn->test_cb, conn->test_cb_cls, + GNUNET_SCHEDULER_REASON_PREREQ_DONE); + } + else + { + service_test_error (conn->test_cb, conn->test_cb_cls); + } + GNUNET_CLIENT_disconnect (conn, GNUNET_NO); +} + + +/** + * Send the 'TEST' message to the service. If successful, prepare to + * receive the reply. + * + * @param cls the 'struct GNUNET_CLIENT_Connection' of the connection to test + * @param size number of bytes available in buf + * @param buf where to write the message + * @return number of bytes written to buf + */ +static size_t +write_test (void *cls, size_t size, void *buf) +{ + struct GNUNET_CLIENT_Connection *conn = cls; + struct GNUNET_MessageHeader *msg; + + if (size < sizeof (struct GNUNET_MessageHeader)) + { +#if DEBUG_CLIENT + LOG (GNUNET_ERROR_TYPE_DEBUG, _("Failure to transmit TEST request.\n")); +#endif + service_test_error (conn->test_cb, conn->test_cb_cls); + GNUNET_CLIENT_disconnect (conn, GNUNET_NO); + return 0; /* client disconnected */ + } +#if DEBUG_CLIENT + LOG (GNUNET_ERROR_TYPE_DEBUG, "Transmitting `%s' request.\n", "TEST"); +#endif + msg = (struct GNUNET_MessageHeader *) buf; + msg->type = htons (GNUNET_MESSAGE_TYPE_TEST); + msg->size = htons (sizeof (struct GNUNET_MessageHeader)); + GNUNET_CLIENT_receive (conn, &confirm_handler, conn, + GNUNET_TIME_absolute_get_remaining + (conn->test_deadline)); + return sizeof (struct GNUNET_MessageHeader); +} + + +/** + * Test if the service is running. If we are given a UNIXPATH or a local address, + * we do this NOT by trying to connect to the service, but by trying to BIND to + * the same port. If the BIND fails, we know the service is running. + * + * @param service name of the service to wait for + * @param cfg configuration to use + * @param timeout how long to wait at most + * @param task task to run if service is running + * (reason will be "PREREQ_DONE" (service running) + * or "TIMEOUT" (service not known to be running)) + * @param task_cls closure for task + */ +void +GNUNET_CLIENT_service_test (const char *service, + const struct GNUNET_CONFIGURATION_Handle *cfg, + struct GNUNET_TIME_Relative timeout, + GNUNET_SCHEDULER_Task task, void *task_cls) +{ + char *hostname; + unsigned long long port; + struct GNUNET_NETWORK_Handle *sock; + struct GNUNET_CLIENT_Connection *conn; + +#if DEBUG_CLIENT + LOG (GNUNET_ERROR_TYPE_DEBUG, "Testing if service `%s' is running.\n", + service); +#endif +#ifdef AF_UNIX + { + /* probe UNIX support */ + struct sockaddr_un s_un; + size_t slen; + char *unixpath; + + unixpath = NULL; + if ((GNUNET_OK == GNUNET_CONFIGURATION_get_value_string (cfg, service, "UNIXPATH", &unixpath)) && (0 < strlen (unixpath))) /* We have a non-NULL unixpath, does that mean it's valid? */ + { + if (strlen (unixpath) >= sizeof (s_un.sun_path)) + { + LOG (GNUNET_ERROR_TYPE_WARNING, + _("UNIXPATH `%s' too long, maximum length is %llu\n"), unixpath, + sizeof (s_un.sun_path)); + } + else + { + sock = GNUNET_NETWORK_socket_create (PF_UNIX, SOCK_STREAM, 0); + if (sock != NULL) + { + memset (&s_un, 0, sizeof (s_un)); + s_un.sun_family = AF_UNIX; + slen = strlen (unixpath) + 1; + if (slen >= sizeof (s_un.sun_path)) + slen = sizeof (s_un.sun_path) - 1; + memcpy (s_un.sun_path, unixpath, slen); + s_un.sun_path[slen] = '\0'; + slen = sizeof (struct sockaddr_un); +#if LINUX + s_un.sun_path[0] = '\0'; +#endif +#if HAVE_SOCKADDR_IN_SIN_LEN + s_un.sun_len = (u_char) slen; +#endif + if (GNUNET_OK != + GNUNET_NETWORK_socket_bind (sock, (const struct sockaddr *) &s_un, + slen)) + { + /* failed to bind => service must be running */ + GNUNET_free (unixpath); + (void) GNUNET_NETWORK_socket_close (sock); + GNUNET_SCHEDULER_add_continuation (task, task_cls, + GNUNET_SCHEDULER_REASON_PREREQ_DONE); + return; + } + (void) GNUNET_NETWORK_socket_close (sock); + } + /* let's try IP */ + } + } + GNUNET_free_non_null (unixpath); + } +#endif + + hostname = NULL; + if ((GNUNET_OK != + GNUNET_CONFIGURATION_get_value_number (cfg, service, "PORT", &port)) || + (port > 65535) || + (GNUNET_OK != + GNUNET_CONFIGURATION_get_value_string (cfg, service, "HOSTNAME", + &hostname))) + { + /* UNIXPATH failed (if possible) AND IP failed => error */ + service_test_error (task, task_cls); + return; + } + + if (0 == strcmp ("localhost", hostname) +#if !LINUX + && 0 +#endif + ) + { + /* can test using 'bind' */ + struct sockaddr_in s_in; + + memset (&s_in, 0, sizeof (s_in)); +#if HAVE_SOCKADDR_IN_SIN_LEN + s_in.sin_len = sizeof (struct sockaddr_in); +#endif + s_in.sin_family = AF_INET; + s_in.sin_port = htons (port); + + sock = GNUNET_NETWORK_socket_create (AF_INET, SOCK_STREAM, 0); + if (sock != NULL) + { + if (GNUNET_OK != + GNUNET_NETWORK_socket_bind (sock, (const struct sockaddr *) &s_in, + sizeof (s_in))) + { + /* failed to bind => service must be running */ + GNUNET_free (hostname); + (void) GNUNET_NETWORK_socket_close (sock); + GNUNET_SCHEDULER_add_continuation (task, task_cls, + GNUNET_SCHEDULER_REASON_PREREQ_DONE); + return; + } + (void) GNUNET_NETWORK_socket_close (sock); + } + } + + if (0 == strcmp ("ip6-localhost", hostname) +#if !LINUX + && 0 +#endif + ) + { + /* can test using 'bind' */ + struct sockaddr_in6 s_in6; + + memset (&s_in6, 0, sizeof (s_in6)); +#if HAVE_SOCKADDR_IN_SIN_LEN + s_in6.sin6_len = sizeof (struct sockaddr_in6); +#endif + s_in6.sin6_family = AF_INET6; + s_in6.sin6_port = htons (port); + + sock = GNUNET_NETWORK_socket_create (AF_INET6, SOCK_STREAM, 0); + if (sock != NULL) + { + if (GNUNET_OK != + GNUNET_NETWORK_socket_bind (sock, (const struct sockaddr *) &s_in6, + sizeof (s_in6))) + { + /* failed to bind => service must be running */ + GNUNET_free (hostname); + (void) GNUNET_NETWORK_socket_close (sock); + GNUNET_SCHEDULER_add_continuation (task, task_cls, + GNUNET_SCHEDULER_REASON_PREREQ_DONE); + return; + } + (void) GNUNET_NETWORK_socket_close (sock); + } + } + + if (((0 == strcmp ("localhost", hostname)) || + (0 == strcmp ("ip6-localhost", hostname))) +#if !LINUX + && 0 +#endif + ) + { + /* all binds succeeded => claim service not running right now */ + GNUNET_free_non_null (hostname); + service_test_error (task, task_cls); + return; + } + GNUNET_free_non_null (hostname); + + /* non-localhost, try 'connect' method */ + conn = GNUNET_CLIENT_connect (service, cfg); + if (conn == NULL) + { + LOG (GNUNET_ERROR_TYPE_INFO, + _("Could not connect to service `%s', must not be running.\n"), + service); + service_test_error (task, task_cls); + return; + } + conn->test_cb = task; + conn->test_cb_cls = task_cls; + conn->test_deadline = GNUNET_TIME_relative_to_absolute (timeout); + + if (NULL == + GNUNET_CLIENT_notify_transmit_ready (conn, + sizeof (struct GNUNET_MessageHeader), + timeout, GNUNET_YES, &write_test, + conn)) + { + LOG (GNUNET_ERROR_TYPE_WARNING, + _("Failure to transmit request to service `%s'\n"), service); + service_test_error (task, task_cls); + GNUNET_CLIENT_disconnect (conn, GNUNET_NO); + return; + } +} + + +/** + * Connection notifies us about failure or success of + * a transmission request. Either pass it on to our + * user or, if possible, retry. + * + * @param cls our "struct GNUNET_CLIENT_TransmissionHandle" + * @param size number of bytes available for transmission + * @param buf where to write them + * @return number of bytes written to buf + */ +static size_t +client_notify (void *cls, size_t size, void *buf); + + +/** + * This task is run if we should re-try connection to the + * service after a while. + * + * @param cls our "struct GNUNET_CLIENT_TransmitHandle" of the request + * @param tc unused + */ +static void +client_delayed_retry (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) +{ + struct GNUNET_CLIENT_TransmitHandle *th = cls; + struct GNUNET_TIME_Relative delay; + + th->reconnect_task = GNUNET_SCHEDULER_NO_TASK; + if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)) + { +#if DEBUG_CLIENT + LOG (GNUNET_ERROR_TYPE_DEBUG, "Transmission failed due to shutdown.\n"); +#endif + th->sock->th = NULL; + th->notify (th->notify_cls, 0, NULL); + GNUNET_free (th); + return; + } + th->sock->sock = + do_connect (th->sock->service_name, th->sock->cfg, th->sock->attempts++); + if (NULL == th->sock->sock) + { + /* could happen if we're out of sockets */ + delay = + GNUNET_TIME_relative_min (GNUNET_TIME_absolute_get_remaining + (th->timeout), th->sock->back_off); + th->sock->back_off = + GNUNET_TIME_relative_min (GNUNET_TIME_relative_multiply + (th->sock->back_off, 2), + GNUNET_TIME_UNIT_SECONDS); +#if DEBUG_CLIENT + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Transmission failed %u times, trying again in %llums.\n", + MAX_ATTEMPTS - th->attempts_left, + (unsigned long long) delay.rel_value); +#endif + th->reconnect_task = + GNUNET_SCHEDULER_add_delayed (delay, &client_delayed_retry, th); + return; + } + th->th = + GNUNET_CONNECTION_notify_transmit_ready (th->sock->sock, th->size, + GNUNET_TIME_absolute_get_remaining + (th->timeout), &client_notify, + th); + if (th->th == NULL) + { + GNUNET_break (0); + th->sock->th = NULL; + th->notify (th->notify_cls, 0, NULL); + GNUNET_free (th); + return; + } +} + + +/** + * Connection notifies us about failure or success of a transmission + * request. Either pass it on to our user or, if possible, retry. + * + * @param cls our "struct GNUNET_CLIENT_TransmissionHandle" + * @param size number of bytes available for transmission + * @param buf where to write them + * @return number of bytes written to buf + */ +static size_t +client_notify (void *cls, size_t size, void *buf) +{ + struct GNUNET_CLIENT_TransmitHandle *th = cls; + size_t ret; + struct GNUNET_TIME_Relative delay; + + th->th = NULL; + th->sock->th = NULL; + if (buf == NULL) + { + delay = GNUNET_TIME_absolute_get_remaining (th->timeout); + delay.rel_value /= 2; + if ((0 != + (GNUNET_SCHEDULER_REASON_SHUTDOWN & GNUNET_SCHEDULER_get_reason ())) || + (GNUNET_YES != th->auto_retry) || (0 == --th->attempts_left) || + (delay.rel_value < 1)) + { +#if DEBUG_CLIENT + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Transmission failed %u times, giving up.\n", + MAX_ATTEMPTS - th->attempts_left); +#endif + GNUNET_break (0 == th->notify (th->notify_cls, 0, NULL)); + GNUNET_free (th); + return 0; + } + /* auto-retry */ +#if DEBUG_CLIENT + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Failed to connect to `%s', automatically trying again.\n", + th->sock->service_name); +#endif + GNUNET_CONNECTION_destroy (th->sock->sock, GNUNET_NO); + th->sock->sock = NULL; + delay = GNUNET_TIME_relative_min (delay, th->sock->back_off); + th->sock->back_off = + GNUNET_TIME_relative_min (GNUNET_TIME_relative_multiply + (th->sock->back_off, 2), + GNUNET_TIME_UNIT_SECONDS); +#if DEBUG_CLIENT + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Transmission failed %u times, trying again in %llums.\n", + MAX_ATTEMPTS - th->attempts_left, + (unsigned long long) delay.rel_value); +#endif + th->sock->th = th; + th->reconnect_task = + GNUNET_SCHEDULER_add_delayed (delay, &client_delayed_retry, th); + return 0; + } + GNUNET_assert (size >= th->size); + ret = th->notify (th->notify_cls, size, buf); + GNUNET_free (th); + return ret; +} + + +/** + * Ask the client to call us once the specified number of bytes + * are free in the transmission buffer. May call the notify + * method immediately if enough space is available. + * + * @param sock connection to the service + * @param size number of bytes to send + * @param timeout after how long should we give up (and call + * notify with buf NULL and size 0)? + * @param auto_retry if the connection to the service dies, should we + * automatically re-connect and retry (within the timeout period) + * or should we immediately fail in this case? Pass GNUNET_YES + * if the caller does not care about temporary connection errors, + * for example because the protocol is stateless + * @param notify function to call + * @param notify_cls closure for notify + * @return NULL if our buffer will never hold size bytes, + * a handle if the notify callback was queued (can be used to cancel) + */ +struct GNUNET_CLIENT_TransmitHandle * +GNUNET_CLIENT_notify_transmit_ready (struct GNUNET_CLIENT_Connection *sock, + size_t size, + struct GNUNET_TIME_Relative timeout, + int auto_retry, + GNUNET_CONNECTION_TransmitReadyNotify + notify, void *notify_cls) +{ + struct GNUNET_CLIENT_TransmitHandle *th; + + if (NULL != sock->th) + { + /* If this breaks, you most likley called this function twice without waiting + * for completion or canceling the request */ + GNUNET_break (0); + return NULL; + } + th = GNUNET_malloc (sizeof (struct GNUNET_CLIENT_TransmitHandle)); + th->sock = sock; + th->size = size; + th->timeout = GNUNET_TIME_relative_to_absolute (timeout); + th->auto_retry = auto_retry; + th->notify = notify; + th->notify_cls = notify_cls; + th->attempts_left = MAX_ATTEMPTS; + sock->th = th; + if (sock->sock == NULL) + { + th->reconnect_task = + GNUNET_SCHEDULER_add_delayed (sock->back_off, &client_delayed_retry, + th); + + } + else + { + th->th = + GNUNET_CONNECTION_notify_transmit_ready (sock->sock, size, timeout, + &client_notify, th); + if (NULL == th->th) + { + GNUNET_break (0); + GNUNET_free (th); + sock->th = NULL; + return NULL; + } + } + return th; +} + + +/** + * Cancel a request for notification. + * + * @param th handle from the original request. + */ +void +GNUNET_CLIENT_notify_transmit_ready_cancel (struct GNUNET_CLIENT_TransmitHandle + *th) +{ + if (th->reconnect_task != GNUNET_SCHEDULER_NO_TASK) + { + GNUNET_assert (NULL == th->th); + GNUNET_SCHEDULER_cancel (th->reconnect_task); + th->reconnect_task = GNUNET_SCHEDULER_NO_TASK; + } + else + { + GNUNET_assert (NULL != th->th); + GNUNET_CONNECTION_notify_transmit_ready_cancel (th->th); + } + th->sock->th = NULL; + GNUNET_free (th); +} + + +/** + * Function called to notify a client about the socket + * begin ready to queue the message. "buf" will be + * NULL and "size" zero if the socket was closed for + * writing in the meantime. + * + * @param cls closure of type "struct TransmitGetResponseContext*" + * @param size number of bytes available in buf + * @param buf where the callee should write the message + * @return number of bytes written to buf + */ +static size_t +transmit_for_response (void *cls, size_t size, void *buf) +{ + struct TransmitGetResponseContext *tc = cls; + uint16_t msize; + + tc->sock->tag = NULL; + msize = ntohs (tc->hdr->size); + if (NULL == buf) + { +#if DEBUG_CLIENT + LOG (GNUNET_ERROR_TYPE_DEBUG, + _("Could not submit request, not expecting to receive a response.\n")); +#endif + if (NULL != tc->rn) + tc->rn (tc->rn_cls, NULL); + GNUNET_free (tc); + return 0; + } + GNUNET_assert (size >= msize); + memcpy (buf, tc->hdr, msize); + GNUNET_CLIENT_receive (tc->sock, tc->rn, tc->rn_cls, + GNUNET_TIME_absolute_get_remaining (tc->timeout)); + GNUNET_free (tc); + return msize; +} + + +/** + * Convenience API that combines sending a request + * to the service and waiting for a response. + * If either operation times out, the callback + * will be called with a "NULL" response (in which + * case the connection should probably be destroyed). + * + * @param sock connection to use + * @param hdr message to transmit + * @param timeout when to give up (for both transmission + * and for waiting for a response) + * @param auto_retry if the connection to the service dies, should we + * automatically re-connect and retry (within the timeout period) + * or should we immediately fail in this case? Pass GNUNET_YES + * if the caller does not care about temporary connection errors, + * for example because the protocol is stateless + * @param rn function to call with the response + * @param rn_cls closure for rn + * @return GNUNET_OK on success, GNUNET_SYSERR if a request + * is already pending + */ +int +GNUNET_CLIENT_transmit_and_get_response (struct GNUNET_CLIENT_Connection *sock, + const struct GNUNET_MessageHeader *hdr, + struct GNUNET_TIME_Relative timeout, + int auto_retry, + GNUNET_CLIENT_MessageHandler rn, + void *rn_cls) +{ + struct TransmitGetResponseContext *tc; + uint16_t msize; + + if (NULL != sock->th) + return GNUNET_SYSERR; + GNUNET_assert (sock->tag == NULL); + msize = ntohs (hdr->size); + tc = GNUNET_malloc (sizeof (struct TransmitGetResponseContext) + msize); + tc->sock = sock; + tc->hdr = (const struct GNUNET_MessageHeader *) &tc[1]; + memcpy (&tc[1], hdr, msize); + tc->timeout = GNUNET_TIME_relative_to_absolute (timeout); + tc->rn = rn; + tc->rn_cls = rn_cls; + if (NULL == + GNUNET_CLIENT_notify_transmit_ready (sock, msize, timeout, auto_retry, + &transmit_for_response, tc)) + { + GNUNET_break (0); + GNUNET_free (tc); + return GNUNET_SYSERR; + } + sock->tag = tc; + return GNUNET_OK; +} + + + +/* end of client.c */ |