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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.
*/
/**
* @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)
{
GNUNET_break (0);
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 */
|