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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-daemon-vpn-dns.h"
#include "gnunet-daemon-vpn.h"
#include "gnunet-daemon-vpn-helper.h"
#include "gnunet-service-dns-p.h"
#include "gnunet-vpn-packet.h"
/**
* Callback called by notify_transmit_ready; sends dns-queries or rehijack-messages
* to the service-dns
* {{{
*/
size_t
send_query(void* cls, size_t size, void* buf) {
size_t len;
/*
* Send the rehijack-message
*/
if (restart_hijack == 1)
{
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 (head != NULL)
{
struct query_packet_list* query = head;
len = ntohs(query->pkt.hdr.size);
GNUNET_assert(len <= size);
memcpy(buf, &query->pkt.hdr, len);
GNUNET_CONTAINER_DLL_remove (head, tail, query);
GNUNET_free(query);
}
else
{
GNUNET_break(0);
len = 0;
}
/*
* Check whether more data is to be sent
*/
if (head != NULL)
{
GNUNET_CLIENT_notify_transmit_ready(dns_connection, ntohs(head->pkt.hdr.size), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES, &send_query, NULL);
}
else if (restart_hijack == 1)
{
GNUNET_CLIENT_notify_transmit_ready(dns_connection, sizeof(struct GNUNET_MessageHeader), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES, &send_query, NULL);
}
return len;
}
/* }}} */
/**
* Connect to the service-dns
*/
void
connect_to_service_dns (void *cls,
const struct GNUNET_SCHEDULER_TaskContext *tc) {
if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
return;
GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Connecting to service-dns\n");
GNUNET_assert (dns_connection == NULL);
dns_connection = GNUNET_CLIENT_connect ("dns", cfg);
/* This would most likely be a misconfiguration */
GNUNET_assert(dns_connection != NULL);
GNUNET_CLIENT_receive(dns_connection, &dns_answer_handler, NULL, GNUNET_TIME_UNIT_FOREVER_REL);
/* If a packet is already in the list, schedule to send it */
if (head != NULL)
GNUNET_CLIENT_notify_transmit_ready(dns_connection,
ntohs(head->pkt.hdr.size),
GNUNET_TIME_UNIT_FOREVER_REL,
GNUNET_YES,
&send_query,
NULL);
else if (restart_hijack == 1)
{
GNUNET_CLIENT_notify_transmit_ready(dns_connection, sizeof(struct GNUNET_MessageHeader), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES, &send_query, NULL);
}
}
/**
* This receives packets from the service-dns and schedules process_answer to
* handle it
*/
void
dns_answer_handler(void* cls, const struct GNUNET_MessageHeader *msg) {
/* the service disconnected, reconnect after short wait */
if (msg == NULL)
{
GNUNET_CLIENT_disconnect(dns_connection, GNUNET_NO);
dns_connection = NULL;
GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS,
&connect_to_service_dns,
NULL);
return;
}
/* the service did something strange, reconnect immediately */
if (msg->type != htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS))
{
GNUNET_break (0);
GNUNET_CLIENT_disconnect(dns_connection, GNUNET_NO);
dns_connection = NULL;
GNUNET_SCHEDULER_add_now (&connect_to_service_dns,
NULL);
return;
}
void *pkt = GNUNET_malloc(ntohs(msg->size));
memcpy(pkt, msg, ntohs(msg->size));
GNUNET_SCHEDULER_add_now(process_answer, pkt);
GNUNET_CLIENT_receive(dns_connection, &dns_answer_handler, NULL, GNUNET_TIME_UNIT_FOREVER_REL);
}
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