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Diffstat (limited to 'src/peerinfo/peerinfo_api_notify.c')
| -rw-r--r-- | src/peerinfo/peerinfo_api_notify.c | 292 |
1 files changed, 292 insertions, 0 deletions
diff --git a/src/peerinfo/peerinfo_api_notify.c b/src/peerinfo/peerinfo_api_notify.c new file mode 100644 index 0000000..a0588db --- /dev/null +++ b/src/peerinfo/peerinfo_api_notify.c @@ -0,0 +1,292 @@ +/* + This file is part of GNUnet. + (C) 2001, 2002, 2004, 2005, 2007, 2009, 2010 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 3, 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 peerinfo/peerinfo_api_notify.c + * @brief notify API to access peerinfo service + * @author Christian Grothoff + */ +#include "platform.h" +#include "gnunet_client_lib.h" +#include "gnunet_peerinfo_service.h" +#include "gnunet_protocols.h" +#include "gnunet_time_lib.h" +#include "peerinfo.h" + +#define LOG(kind,...) GNUNET_log_from (kind, "nse-api",__VA_ARGS__) + +/** + * Context for the info handler. + */ +struct GNUNET_PEERINFO_NotifyContext +{ + + /** + * Our connection to the PEERINFO service. + */ + struct GNUNET_CLIENT_Connection *client; + + /** + * Function to call with information. + */ + GNUNET_PEERINFO_Processor callback; + + /** + * Closure for callback. + */ + void *callback_cls; + + /** + * Handle to our initial request for message transmission to + * the peerinfo service. + */ + struct GNUNET_CLIENT_TransmitHandle *init; + + /** + * Configuration. + */ + const struct GNUNET_CONFIGURATION_Handle *cfg; + + /** + * Tasked used for delayed re-connection attempt. + */ + GNUNET_SCHEDULER_TaskIdentifier task; + +}; + + +/** + * Send a request to the peerinfo service to start being + * notified about all changes to peer information. + * + * @param nc our context + */ +static void +request_notifications (struct GNUNET_PEERINFO_NotifyContext *nc); + + +/** + * Read notifications from the client handle and pass them + * to the callback. + * + * @param nc our context + */ +static void +receive_notifications (struct GNUNET_PEERINFO_NotifyContext *nc); + + +/** + * Task to re-try connecting to peerinfo. + * + * @param cls the 'struct GNUNET_PEERINFO_NotifyContext' + * @param tc scheduler context + */ +static void +reconnect (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) +{ + struct GNUNET_PEERINFO_NotifyContext *nc = cls; + + nc->task = GNUNET_SCHEDULER_NO_TASK; + nc->client = GNUNET_CLIENT_connect ("peerinfo", nc->cfg); + if (NULL == nc->client) + { + /* ugh */ + nc->task = + GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS, &reconnect, nc); + return; + } + request_notifications (nc); +} + + +/** + * Receive a peerinfo information message, process it and + * go for more. + * + * @param cls closure + * @param msg message received, NULL on timeout or fatal error + */ +static void +process_notification (void *cls, const struct GNUNET_MessageHeader *msg) +{ + struct GNUNET_PEERINFO_NotifyContext *nc = cls; + const struct InfoMessage *im; + const struct GNUNET_HELLO_Message *hello; + uint16_t ms; + + if (msg == NULL) + { + GNUNET_CLIENT_disconnect (nc->client, GNUNET_NO); + reconnect (nc, NULL); + return; + } + ms = ntohs (msg->size); + if ((ms < sizeof (struct InfoMessage)) || + (ntohs (msg->type) != GNUNET_MESSAGE_TYPE_PEERINFO_INFO)) + { + GNUNET_break (0); + GNUNET_CLIENT_disconnect (nc->client, GNUNET_NO); + nc->client = GNUNET_CLIENT_connect ("peerinfo", nc->cfg); + request_notifications (nc); + return; + } + im = (const struct InfoMessage *) msg; + hello = NULL; + if (ms > sizeof (struct InfoMessage) + sizeof (struct GNUNET_MessageHeader)) + { + hello = (const struct GNUNET_HELLO_Message *) &im[1]; + if (ms != sizeof (struct InfoMessage) + GNUNET_HELLO_size (hello)) + { + GNUNET_break (0); + GNUNET_CLIENT_disconnect (nc->client, GNUNET_NO); + nc->client = GNUNET_CLIENT_connect ("peerinfo", nc->cfg); + request_notifications (nc); + return; + } + } +#if DEBUG_PEERINFO + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Received information about peer `%s' from peerinfo database\n", + GNUNET_i2s (&im->peer)); +#endif + nc->callback (nc->callback_cls, &im->peer, hello, NULL); + receive_notifications (nc); +} + + +/** + * Read notifications from the client handle and pass them + * to the callback. + * + * @param nc our context + */ +static void +receive_notifications (struct GNUNET_PEERINFO_NotifyContext *nc) +{ + GNUNET_CLIENT_receive (nc->client, &process_notification, nc, + GNUNET_TIME_UNIT_FOREVER_REL); +} + + +/** + * Transmit our init-notify request, start receiving. + * + * @param cls closure (our 'struct GNUNET_PEERINFO_NotifyContext') + * @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_notify_request (void *cls, size_t size, void *buf) +{ + struct GNUNET_PEERINFO_NotifyContext *nc = cls; + struct GNUNET_MessageHeader hdr; + + nc->init = NULL; + if (buf == NULL) + { + GNUNET_CLIENT_disconnect (nc->client, GNUNET_NO); + nc->client = GNUNET_CLIENT_connect ("peerinfo", nc->cfg); + request_notifications (nc); + return 0; + } + GNUNET_assert (size >= sizeof (struct GNUNET_MessageHeader)); + hdr.size = htons (sizeof (struct GNUNET_MessageHeader)); + hdr.type = htons (GNUNET_MESSAGE_TYPE_PEERINFO_NOTIFY); + memcpy (buf, &hdr, sizeof (struct GNUNET_MessageHeader)); + receive_notifications (nc); + return sizeof (struct GNUNET_MessageHeader); +} + + +/** + * Send a request to the peerinfo service to start being + * notified about all changes to peer information. + * + * @param nc our context + */ +static void +request_notifications (struct GNUNET_PEERINFO_NotifyContext *nc) +{ + GNUNET_assert (NULL == nc->init); + nc->init = + GNUNET_CLIENT_notify_transmit_ready (nc->client, + sizeof (struct GNUNET_MessageHeader), + GNUNET_TIME_UNIT_FOREVER_REL, + GNUNET_YES, &transmit_notify_request, + nc); +} + + +/** + * Call a method whenever our known information about peers + * changes. Initially calls the given function for all known + * peers and then only signals changes. + * + * @param cfg configuration to use + * @param callback the method to call for each peer + * @param callback_cls closure for callback + * @return NULL on error + */ +struct GNUNET_PEERINFO_NotifyContext * +GNUNET_PEERINFO_notify (const struct GNUNET_CONFIGURATION_Handle *cfg, + GNUNET_PEERINFO_Processor callback, void *callback_cls) +{ + struct GNUNET_PEERINFO_NotifyContext *nc; + struct GNUNET_CLIENT_Connection *client; + + client = GNUNET_CLIENT_connect ("peerinfo", cfg); + if (client == NULL) + { + LOG (GNUNET_ERROR_TYPE_WARNING, _("Could not connect to `%s' service.\n"), + "peerinfo"); + return NULL; + } + nc = GNUNET_malloc (sizeof (struct GNUNET_PEERINFO_NotifyContext)); + nc->cfg = cfg; + nc->client = client; + nc->callback = callback; + nc->callback_cls = callback_cls; + request_notifications (nc); + return nc; +} + + +/** + * Stop notifying about changes. + * + * @param nc context to stop notifying + */ +void +GNUNET_PEERINFO_notify_cancel (struct GNUNET_PEERINFO_NotifyContext *nc) +{ + if (NULL != nc->init) + { + GNUNET_CLIENT_notify_transmit_ready_cancel (nc->init); + nc->init = NULL; + } + if (NULL != nc->client) + GNUNET_CLIENT_disconnect (nc->client, GNUNET_NO); + if (GNUNET_SCHEDULER_NO_TASK != nc->task) + GNUNET_SCHEDULER_cancel (nc->task); + GNUNET_free (nc); +} + +/* end of peerinfo_api_notify.c */ |