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/*
This file is part of GNUnet.
(C) 2010 Christian Grothoff
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 vpn/gnunet-daemon-vpn-dns.c
* @brief
* @author Philipp Toelke
*/
#include <platform.h>
#include <gnunet_common.h>
#include <gnunet_client_lib.h>
#include <gnunet_os_lib.h>
#include <gnunet_mesh_service.h>
#include <gnunet_protocols.h>
#include <gnunet_server_lib.h>
#include <gnunet_container_lib.h>
#include <block_dns.h>
#include "gnunet_dns_service.h"
struct GNUNET_DNS_Handle
{
struct query_packet_list *head;
struct query_packet_list *tail;
struct GNUNET_CLIENT_Connection *dns_connection;
unsigned char restart_hijack;
struct GNUNET_CLIENT_TransmitHandle *dns_transmit_handle;
const struct GNUNET_CONFIGURATION_Handle *cfg;
GNUNET_SCHEDULER_Task process_answer_cb;
void *process_answer_cb_cls;
};
/**
* Callback called by notify_transmit_ready; sends dns-queries or rehijack-messages
* to the service-dns
* {{{
*/
size_t
send_query (void *cls GNUNET_UNUSED, size_t size, void *buf)
{
struct GNUNET_DNS_Handle *h = cls;
size_t len;
h->dns_transmit_handle = NULL;
/*
* Send the rehijack-message
*/
if (h->restart_hijack == 1)
{
h->restart_hijack = 0;
/*
* The message is just a header
*/
GNUNET_assert (sizeof (struct GNUNET_MessageHeader) <= size);
struct GNUNET_MessageHeader *hdr = buf;
len = sizeof (struct GNUNET_MessageHeader);
hdr->size = htons (len);
hdr->type = htons (GNUNET_MESSAGE_TYPE_REHIJACK);
}
else if (h->head != NULL)
{
struct query_packet_list *query = h->head;
len = ntohs (query->pkt.hdr.size);
GNUNET_assert (len <= size);
memcpy (buf, &query->pkt.hdr, len);
GNUNET_CONTAINER_DLL_remove (h->head, h->tail, query);
GNUNET_free (query);
}
else
{
GNUNET_break (0);
len = 0;
}
/*
* Check whether more data is to be sent
*/
if (h->head != NULL)
{
h->dns_transmit_handle =
GNUNET_CLIENT_notify_transmit_ready (h->dns_connection,
ntohs (h->head->pkt.hdr.size),
GNUNET_TIME_UNIT_FOREVER_REL,
GNUNET_YES, &send_query, h);
}
else if (h->restart_hijack == 1)
{
h->dns_transmit_handle =
GNUNET_CLIENT_notify_transmit_ready (h->dns_connection,
sizeof (struct
GNUNET_MessageHeader),
GNUNET_TIME_UNIT_FOREVER_REL,
GNUNET_YES, &send_query, h);
}
return len;
}
/* }}} */
/**
* This receives packets from the service-dns and schedules process_answer to
* handle it
*/
static void
dns_answer_handler (void *cls,
const struct GNUNET_MessageHeader *msg)
{
struct GNUNET_DNS_Handle *h = cls;
/* the service disconnected, reconnect after short wait */
if (msg == NULL)
{
if (h->dns_transmit_handle != NULL)
GNUNET_CLIENT_notify_transmit_ready_cancel (h->dns_transmit_handle);
h->dns_transmit_handle = NULL;
GNUNET_CLIENT_disconnect (h->dns_connection, GNUNET_NO);
h->dns_connection = NULL;
#if 0
h->conn_task =
GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS,
&connect_to_service_dns, h);
#endif
return;
}
/* the service did something strange, reconnect immediately */
if (msg->type != htons (GNUNET_MESSAGE_TYPE_VPN_DNS_LOCAL_RESPONSE_DNS))
{
GNUNET_break (0);
GNUNET_CLIENT_disconnect (h->dns_connection, GNUNET_NO);
h->dns_connection = NULL;
#if 0
conn_task = GNUNET_SCHEDULER_add_now (&connect_to_service_dns, NULL);
#endif
return;
}
void *pkt = GNUNET_malloc (ntohs (msg->size));
memcpy (pkt, msg, ntohs (msg->size));
GNUNET_SCHEDULER_add_now (h->process_answer_cb, pkt);
GNUNET_CLIENT_receive (h->dns_connection, &dns_answer_handler, h,
GNUNET_TIME_UNIT_FOREVER_REL);
}
/**
* Connect to the service-dns
*/
struct GNUNET_DNS_Handle *
GNUNET_DNS_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
GNUNET_SCHEDULER_Task cb,
void *cb_cls)
{
struct GNUNET_DNS_Handle *h;
h = GNUNET_malloc (sizeof (struct GNUNET_DNS_Handle));
h->cfg = cfg;
h->process_answer_cb = cb;
h->process_answer_cb_cls = cb_cls;
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Connecting to service-dns\n");
h->dns_connection = GNUNET_CLIENT_connect ("dns", h->cfg);
/* This would most likely be a misconfiguration */
GNUNET_assert (NULL != h->dns_connection);
GNUNET_CLIENT_receive (h->dns_connection,
&dns_answer_handler, NULL,
GNUNET_TIME_UNIT_FOREVER_REL);
/* If a packet is already in the list, schedule to send it */
if (h->dns_transmit_handle == NULL && h->head != NULL)
h->dns_transmit_handle =
GNUNET_CLIENT_notify_transmit_ready (h->dns_connection,
ntohs (h->head->pkt.hdr.size),
GNUNET_TIME_UNIT_FOREVER_REL,
GNUNET_YES, &send_query, h);
else if (h->dns_transmit_handle == NULL && h->restart_hijack == 1)
{
h->dns_transmit_handle =
GNUNET_CLIENT_notify_transmit_ready (h->dns_connection,
sizeof (struct
GNUNET_MessageHeader),
GNUNET_TIME_UNIT_FOREVER_REL,
GNUNET_YES, &send_query, NULL);
}
return h;
}
void
GNUNET_DNS_restart_hijack (struct GNUNET_DNS_Handle *h)
{
h->restart_hijack = 1;
if (NULL != h->dns_connection && h->dns_transmit_handle == NULL)
h->dns_transmit_handle =
GNUNET_CLIENT_notify_transmit_ready (h->dns_connection,
sizeof (struct
GNUNET_MessageHeader),
GNUNET_TIME_UNIT_FOREVER_REL,
GNUNET_YES, &send_query, h);
}
/**
* FIXME: we should not expost our internal structures like this.
* Just a quick initial hack.
*/
void
GNUNET_DNS_queue_request (struct GNUNET_DNS_Handle *h,
struct query_packet_list *q)
{
GNUNET_CONTAINER_DLL_insert_tail (h->head, h->tail, q);
if (h->dns_connection != NULL && h->dns_transmit_handle == NULL)
h->dns_transmit_handle =
GNUNET_CLIENT_notify_transmit_ready (h->dns_connection, ntohs(q->pkt.hdr.size),
GNUNET_TIME_UNIT_FOREVER_REL,
GNUNET_YES, &send_query,
h);
}
void
GNUNET_DNS_disconnect (struct GNUNET_DNS_Handle *h)
{
if (h->dns_connection != NULL)
{
GNUNET_CLIENT_disconnect (h->dns_connection, GNUNET_NO);
h->dns_connection = NULL;
}
GNUNET_free (h);
}
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