2 This file is part of GNUnet.
3 (C) 2009 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 3, or (at your
8 option) any later version.
10 GNUnet is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with GNUnet; see the file COPYING. If not, write to the
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA.
22 * @file vpn/gnunet-service-dns.c
23 * @author Philipp Tölke
26 #include "gnunet_getopt_lib.h"
27 #include "gnunet_service_lib.h"
28 #include "gnunet_network_lib.h"
29 #include "gnunet_os_lib.h"
30 #include "gnunet-service-dns-p.h"
31 #include "gnunet_protocols.h"
32 #include "gnunet-vpn-packet.h"
33 #include "gnunet-vpn-pretty-print.h"
37 struct GNUNET_SCHEDULER_Handle *sched;
39 struct GNUNET_NETWORK_Handle *dnsout;
41 unsigned short dnsoutport;
44 static struct dns_cls mycls;
46 void hijack(unsigned short port) {
49 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Hijacking, port is %d\n", port);
50 snprintf(port_s, 6, "%d", port);
51 GNUNET_OS_start_process(NULL, NULL, "gnunet-helper-hijack-dns", "gnunet-hijack-dns", port_s, NULL);
54 void unhijack(unsigned short port) {
57 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "unHijacking, port is %d\n", port);
58 snprintf(port_s, 6, "%d", port);
59 GNUNET_OS_start_process(NULL, NULL, "gnunet-helper-hijack-dns", "gnunet-hijack-dns", "-d", port_s, NULL);
62 void receive_query(void *cls, struct GNUNET_SERVER_Client *client, const struct GNUNET_MessageHeader *message)
64 struct query_packet* pkt = (struct query_packet*)message;
65 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Received query of length %d\n", ntohs(pkt->hdr.size));
66 struct dns_pkt* dns = (struct dns_pkt*)pkt->data;
68 struct sockaddr_in dest;
69 memset(&dest, 0, sizeof dest);
70 dest.sin_port = htons(53);
71 dest.sin_addr.s_addr = pkt->orig_to;
73 * State merken, damit die Antwort korrekt zurückgeschickt werden kann
76 int r = GNUNET_NETWORK_socket_sendto(mycls.dnsout, dns, ntohs(pkt->hdr.size) - sizeof(struct query_packet) + 1, (struct sockaddr*) &dest, sizeof dest);
77 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "send %d bytes to socket\n", r);
79 GNUNET_SERVER_receive_done(client, GNUNET_OK);
82 static void read_response (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
83 unsigned char buf[65536];
84 struct dns_pkt* dns = (struct dns_pkt*)buf;
86 if (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
90 r = GNUNET_NETWORK_socket_recv(mycls.dnsout, buf, 65536);
94 GNUNET_SCHEDULER_add_read_net(mycls.sched, GNUNET_TIME_UNIT_FOREVER_REL, mycls.dnsout, &read_response, NULL);
99 * Task run during shutdown.
105 cleanup_task (void *cls,
106 const struct GNUNET_SCHEDULER_TaskContext *tc)
108 unhijack(mycls.dnsoutport);
113 * @param sched scheduler to use
114 * @param server the initialized server
115 * @param cfg configuration to use
119 struct GNUNET_SCHEDULER_Handle *sched,
120 struct GNUNET_SERVER_Handle *server,
121 const struct GNUNET_CONFIGURATION_Handle *cfg)
123 static const struct GNUNET_SERVER_MessageHandler handlers[] = {
124 /* callback, cls, type, size */
125 {&receive_query, NULL, GNUNET_MESSAGE_TYPE_LOCAL_QUERY_DNS, 0},
128 struct sockaddr_in addr;
131 mycls.dnsout = GNUNET_NETWORK_socket_create (AF_INET, SOCK_DGRAM, 0);
132 if (mycls.dnsout == NULL)
134 memset(&addr, 0, sizeof(struct sockaddr_in));
136 int err = GNUNET_NETWORK_socket_bind (mycls.dnsout,
137 (struct sockaddr*)&addr,
138 sizeof(struct sockaddr_in));
140 if (err != GNUNET_YES) {
141 GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "Could not bind a port, exiting\n");
144 socklen_t addrlen = sizeof(struct sockaddr_in);
145 err = getsockname(GNUNET_NETWORK_get_fd(mycls.dnsout),
146 (struct sockaddr*) &addr,
149 mycls.dnsoutport = htons(addr.sin_port);
151 hijack(htons(addr.sin_port));
153 GNUNET_SCHEDULER_add_read_net(sched, GNUNET_TIME_UNIT_FOREVER_REL, mycls.dnsout, &read_response, NULL);
155 GNUNET_SERVER_add_handlers (server, handlers);
156 GNUNET_SCHEDULER_add_delayed (sched,
157 GNUNET_TIME_UNIT_FOREVER_REL,
163 * The main function for the dns service.
165 * @param argc number of arguments from the command line
166 * @param argv command line arguments
167 * @return 0 ok, 1 on error
170 main (int argc, char *const *argv)
173 GNUNET_SERVICE_run (argc,
176 GNUNET_SERVICE_OPTION_NONE,
177 &run, NULL)) ? 0 : 1;