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- /*
- This file is part of GNUnet.
- Copyright (C) 2001-2014 GNUnet e.V.
- GNUnet is free software: you can redistribute it and/or modify it
- under the terms of the GNU Affero General Public License as published
- by the Free Software Foundation, either version 3 of the License,
- 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
- Affero General Public License for more details.
- You should have received a copy of the GNU Affero General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>.
- SPDX-License-Identifier: AGPL3.0-or-later
- */
- /**
- * @file peerinfo/peerinfo_api.c
- * @brief API to access peerinfo service
- * @author Christian Grothoff
- */
- #include "platform.h"
- #include "gnunet_util_lib.h"
- #include "gnunet_protocols.h"
- #include "peerinfo.h"
- #define LOG(kind,...) GNUNET_log_from (kind, "peerinfo-api",__VA_ARGS__)
- /**
- * Context for an iteration request.
- */
- struct GNUNET_PEERINFO_IteratorContext
- {
- /**
- * Kept in a DLL.
- */
- struct GNUNET_PEERINFO_IteratorContext *next;
- /**
- * Kept in a DLL.
- */
- struct GNUNET_PEERINFO_IteratorContext *prev;
- /**
- * Handle to the PEERINFO service.
- */
- struct GNUNET_PEERINFO_Handle *h;
- /**
- * Function to call with the results.
- */
- GNUNET_PEERINFO_Processor callback;
- /**
- * Closure for @e callback.
- */
- void *callback_cls;
- /**
- * Peer we are interested in (only valid if iteration was restricted to one peer).
- */
- struct GNUNET_PeerIdentity peer;
- /**
- * Is @e peer set?
- */
- int have_peer;
- /**
- * Only include friends in reply?
- */
- int include_friend_only;
- };
- /**
- * Handle to the peerinfo service.
- */
- struct GNUNET_PEERINFO_Handle
- {
- /**
- * Our configuration.
- */
- const struct GNUNET_CONFIGURATION_Handle *cfg;
- /**
- * Connection to the service.
- */
- struct GNUNET_MQ_Handle *mq;
- /**
- * Head of iterator DLL.
- */
- struct GNUNET_PEERINFO_IteratorContext *ic_head;
- /**
- * Tail of iterator DLL.
- */
- struct GNUNET_PEERINFO_IteratorContext *ic_tail;
- /**
- * ID for a reconnect task.
- */
- struct GNUNET_SCHEDULER_Task *r_task;
- };
- /**
- * Close the existing connection to PEERINFO and reconnect.
- *
- * @param h handle to the service
- */
- static void
- reconnect (struct GNUNET_PEERINFO_Handle *h);
- /**
- * Connect to the peerinfo service.
- *
- * @param cfg configuration to use
- * @return NULL on error (configuration related, actual connection
- * establishment may happen asynchronously).
- */
- struct GNUNET_PEERINFO_Handle *
- GNUNET_PEERINFO_connect (const struct GNUNET_CONFIGURATION_Handle *cfg)
- {
- struct GNUNET_PEERINFO_Handle *h;
- h = GNUNET_new (struct GNUNET_PEERINFO_Handle);
- h->cfg = cfg;
- reconnect (h);
- if (NULL == h->mq)
- {
- GNUNET_free (h);
- return NULL;
- }
- return h;
- }
- /**
- * Disconnect from the peerinfo service. Note that all iterators must
- * have completed or have been cancelled by the time this function is
- * called (otherwise, calling this function is a serious error).
- * Furthermore, if #GNUNET_PEERINFO_add_peer() operations are still
- * pending, they will be cancelled silently on disconnect.
- *
- * @param h handle to disconnect
- */
- void
- GNUNET_PEERINFO_disconnect (struct GNUNET_PEERINFO_Handle *h)
- {
- struct GNUNET_PEERINFO_IteratorContext *ic;
- while (NULL != (ic = h->ic_head))
- {
- GNUNET_CONTAINER_DLL_remove (h->ic_head,
- h->ic_tail,
- ic);
- GNUNET_free (ic);
- }
- if (NULL != h->mq)
- {
- GNUNET_MQ_destroy (h->mq);
- h->mq = NULL;
- }
- if (NULL != h->r_task)
- {
- GNUNET_SCHEDULER_cancel (h->r_task);
- h->r_task = NULL;
- }
- GNUNET_free (h);
- }
- /**
- * Task scheduled to re-try connecting to the peerinfo service.
- *
- * @param cls the `struct GNUNET_PEERINFO_Handle *`
- */
- static void
- reconnect_task (void *cls)
- {
- struct GNUNET_PEERINFO_Handle *h = cls;
- h->r_task = NULL;
- reconnect (h);
- }
- /**
- * We encountered an error, reconnect to the PEERINFO service.
- *
- * @param h handle to reconnect
- */
- static void
- do_reconnect (struct GNUNET_PEERINFO_Handle *h)
- {
- struct GNUNET_PEERINFO_IteratorContext *ic = h->ic_head;
- GNUNET_MQ_destroy (h->mq);
- h->mq = NULL;
- if (NULL != ic)
- {
- GNUNET_CONTAINER_DLL_remove (h->ic_head,
- h->ic_tail,
- ic);
- if (NULL != ic->callback)
- ic->callback (ic->callback_cls,
- NULL,
- NULL,
- _("Failed to receive response from `PEERINFO' service."));
- GNUNET_free (ic);
- }
- h->r_task = GNUNET_SCHEDULER_add_now (&reconnect_task,
- h);
- }
- /**
- * We got a disconnect after asking regex to do the announcement.
- * Retry.
- *
- * @param cls the `struct GNUNET_PEERINFO_Handle` to retry
- * @param error error code
- */
- static void
- mq_error_handler (void *cls,
- enum GNUNET_MQ_Error error)
- {
- struct GNUNET_PEERINFO_Handle *h = cls;
- do_reconnect (h);
- }
- /**
- * Function called when we receive an info message. Check it is
- * well-formed.
- *
- * @param cls closure
- * @param im message received
- * @return #GNUNET_OK if the message is OK
- */
- static int
- check_info (void *cls,
- const struct InfoMessage *im)
- {
- struct GNUNET_PEERINFO_Handle *h = cls;
- struct GNUNET_PEERINFO_IteratorContext *ic = h->ic_head;
- uint16_t ms = ntohs (im->header.size) - sizeof (*im);
- if (0 != ntohl (im->reserved))
- {
- GNUNET_break (0);
- return GNUNET_SYSERR;
- }
- if (NULL == ic)
- {
- /* didn't expect a response, bad */
- GNUNET_break (0);
- return GNUNET_SYSERR;
- }
- if ( (GNUNET_YES == ic->have_peer) &&
- (0 != memcmp (&ic->peer,
- &im->peer,
- sizeof (struct GNUNET_PeerIdentity))) )
- {
- /* bogus message (from a different iteration call?); out of sequence! */
- LOG (GNUNET_ERROR_TYPE_ERROR,
- "Received HELLO for peer `%s', expected peer `%s'\n",
- GNUNET_i2s (&im->peer),
- GNUNET_i2s (&ic->peer));
- GNUNET_break (0);
- return GNUNET_SYSERR;
- }
- if (ms > sizeof (struct GNUNET_MessageHeader))
- {
- const struct GNUNET_HELLO_Message *hello;
- struct GNUNET_PeerIdentity id;
- hello = (const struct GNUNET_HELLO_Message *) &im[1];
- if (ms != GNUNET_HELLO_size (hello))
- {
- /* malformed message */
- GNUNET_break (0);
- return GNUNET_SYSERR;
- }
- if (GNUNET_OK !=
- GNUNET_HELLO_get_id (hello,
- &id))
- {
- /* malformed message */
- GNUNET_break (0);
- return GNUNET_SYSERR;
- }
- if (0 != memcmp (&im->peer,
- &id,
- sizeof (struct GNUNET_PeerIdentity)))
- {
- /* malformed message */
- GNUNET_break (0);
- return GNUNET_SYSERR;
- }
- }
- else if (0 != ms)
- {
- /* malformed message */
- GNUNET_break (0);
- return GNUNET_SYSERR;
- }
- return GNUNET_OK;
- }
- /**
- * Handle info message.
- *
- * @param cls closure
- * @param im message received
- */
- static void
- handle_info (void *cls,
- const struct InfoMessage *im)
- {
- struct GNUNET_PEERINFO_Handle *h = cls;
- struct GNUNET_PEERINFO_IteratorContext *ic = h->ic_head;
- const struct GNUNET_HELLO_Message *hello = NULL;
- uint16_t ms;
- ms = ntohs (im->header.size);
- if (ms > sizeof (struct InfoMessage))
- hello = (const struct GNUNET_HELLO_Message *) &im[1];
- if (NULL != ic->callback)
- ic->callback (ic->callback_cls,
- &im->peer,
- hello,
- NULL);
- }
- /**
- * Send the next IC request at the head of the queue.
- *
- * @param h handle
- */
- static void
- send_ic_request (struct GNUNET_PEERINFO_Handle *h)
- {
- struct GNUNET_PEERINFO_IteratorContext *ic = h->ic_head;
- struct GNUNET_MQ_Envelope *env;
- struct ListAllPeersMessage *lapm;
- struct ListPeerMessage *lpm;
- if (NULL == ic)
- {
- GNUNET_break (0);
- return;
- }
- if (NULL == h->mq)
- {
- GNUNET_break (0);
- return;
- }
- if (GNUNET_NO == ic->have_peer)
- {
- LOG (GNUNET_ERROR_TYPE_DEBUG,
- "Requesting list of peers from PEERINFO service\n");
- env = GNUNET_MQ_msg (lapm,
- GNUNET_MESSAGE_TYPE_PEERINFO_GET_ALL);
- lapm->include_friend_only = htonl (ic->include_friend_only);
- }
- else
- {
- LOG (GNUNET_ERROR_TYPE_DEBUG,
- "Requesting information on peer `%s' from PEERINFO service\n",
- GNUNET_i2s (&ic->peer));
- env = GNUNET_MQ_msg (lpm,
- GNUNET_MESSAGE_TYPE_PEERINFO_GET);
- lpm->include_friend_only = htonl (ic->include_friend_only);
- lpm->peer = ic->peer;
- }
- GNUNET_MQ_send (h->mq,
- env);
- }
- /**
- * Type of a function to call when we receive a message from the
- * service. Call the iterator with the result and (if applicable)
- * continue to receive more messages or trigger processing the next
- * event (if applicable).
- *
- * @param cls closure
- * @param msg message received, NULL on timeout or fatal error
- */
- static void
- handle_end_iteration (void *cls,
- const struct GNUNET_MessageHeader *msg)
- {
- struct GNUNET_PEERINFO_Handle *h = cls;
- struct GNUNET_PEERINFO_IteratorContext *ic = h->ic_head;
- if (NULL == ic)
- {
- /* didn't expect a response, reconnect */
- GNUNET_break (0);
- reconnect (h);
- return;
- }
- LOG (GNUNET_ERROR_TYPE_DEBUG,
- "Received end of list of peers from PEERINFO service\n");
- GNUNET_CONTAINER_DLL_remove (h->ic_head,
- h->ic_tail,
- ic);
- if (NULL != h->ic_head)
- send_ic_request (h);
- if (NULL != ic->callback)
- ic->callback (ic->callback_cls,
- NULL,
- NULL,
- NULL);
- GNUNET_free (ic);
- }
- /**
- * Close the existing connection to PEERINFO and reconnect.
- *
- * @param h handle to the service
- */
- static void
- reconnect (struct GNUNET_PEERINFO_Handle *h)
- {
- struct GNUNET_MQ_MessageHandler handlers[] = {
- GNUNET_MQ_hd_var_size (info,
- GNUNET_MESSAGE_TYPE_PEERINFO_INFO,
- struct InfoMessage,
- h),
- GNUNET_MQ_hd_fixed_size (end_iteration,
- GNUNET_MESSAGE_TYPE_PEERINFO_INFO_END,
- struct GNUNET_MessageHeader,
- h),
- GNUNET_MQ_handler_end ()
- };
- if (NULL != h->r_task)
- {
- GNUNET_SCHEDULER_cancel (h->r_task);
- h->r_task = NULL;
- }
- if (NULL != h->mq)
- {
- GNUNET_MQ_destroy (h->mq);
- h->mq = NULL;
- }
- h->mq = GNUNET_CLIENT_connect (h->cfg,
- "peerinfo",
- handlers,
- &mq_error_handler,
- h);
- if (NULL != h->ic_head)
- send_ic_request (h);
- }
- /**
- * Call a method for each known matching host. The callback method
- * will be invoked once for each matching host and then finally once
- * with a NULL pointer. After that final invocation, the iterator
- * context must no longer be used.
- *
- * Instead of calling this function with `peer == NULL` it is often
- * better to use #GNUNET_PEERINFO_notify().
- *
- * @param h handle to the peerinfo service
- * @param include_friend_only include HELLO messages for friends only
- * @param peer restrict iteration to this peer only (can be NULL)
- * @param callback the method to call for each peer
- * @param callback_cls closure for @a callback
- * @return iterator context
- */
- struct GNUNET_PEERINFO_IteratorContext *
- GNUNET_PEERINFO_iterate (struct GNUNET_PEERINFO_Handle *h,
- int include_friend_only,
- const struct GNUNET_PeerIdentity *peer,
- GNUNET_PEERINFO_Processor callback,
- void *callback_cls)
- {
- struct GNUNET_PEERINFO_IteratorContext *ic;
- ic = GNUNET_new (struct GNUNET_PEERINFO_IteratorContext);
- ic->h = h;
- ic->include_friend_only = include_friend_only;
- ic->callback = callback;
- ic->callback_cls = callback_cls;
- if (NULL != peer)
- {
- ic->have_peer = GNUNET_YES;
- ic->peer = *peer;
- }
- GNUNET_CONTAINER_DLL_insert_tail (h->ic_head,
- h->ic_tail,
- ic);
- if (h->ic_head == ic)
- send_ic_request (h);
- return ic;
- }
- /**
- * Cancel an iteration over peer information.
- *
- * @param ic context of the iterator to cancel
- */
- void
- GNUNET_PEERINFO_iterate_cancel (struct GNUNET_PEERINFO_IteratorContext *ic)
- {
- struct GNUNET_PEERINFO_Handle *h = ic->h;
- ic->callback = NULL;
- if (ic == h->ic_head)
- return;
- GNUNET_CONTAINER_DLL_remove (h->ic_head,
- h->ic_tail,
- ic);
- GNUNET_free (ic);
- }
- /**
- * Add a host to the persistent list. This method operates in
- * semi-reliable mode: if the transmission is not completed by
- * the time #GNUNET_PEERINFO_disconnect() is called, it will be
- * aborted. Furthermore, if a second HELLO is added for the
- * same peer before the first one was transmitted, PEERINFO may
- * merge the two HELLOs prior to transmission to the service.
- *
- * @param h handle to the peerinfo service
- * @param hello the verified (!) HELLO message
- * @param cont continuation to call when done, NULL is allowed
- * @param cont_cls closure for @a cont
- * @return handle to cancel add operation; all pending
- * 'add' operations will be cancelled automatically
- * on disconnect, so it is not necessary to keep this
- * handle (unless @a cont is NULL and at some point
- * calling @a cont must be prevented)
- */
- struct GNUNET_MQ_Envelope *
- GNUNET_PEERINFO_add_peer (struct GNUNET_PEERINFO_Handle *h,
- const struct GNUNET_HELLO_Message *hello,
- GNUNET_SCHEDULER_TaskCallback cont,
- void *cont_cls)
- {
- struct GNUNET_MQ_Envelope *env;
- struct GNUNET_PeerIdentity peer;
- if (NULL == h->mq)
- return NULL;
- GNUNET_assert (GNUNET_OK ==
- GNUNET_HELLO_get_id (hello,
- &peer));
- LOG (GNUNET_ERROR_TYPE_DEBUG,
- "Adding peer `%s' to PEERINFO database\n",
- GNUNET_i2s (&peer));
- env = GNUNET_MQ_msg_copy ((const struct GNUNET_MessageHeader *) hello);
- if (NULL != cont)
- GNUNET_MQ_notify_sent (env,
- cont,
- cont_cls);
- GNUNET_MQ_send (h->mq,
- env);
- return env;
- }
- /* end of peerinfo_api.c */
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