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authorNathan S. Evans <evans@in.tum.de>2010-08-18 15:37:41 +0000
committerNathan S. Evans <evans@in.tum.de>2010-08-18 15:37:41 +0000
commit192a6a6663b55a491987f8423c22527f12d1f46b (patch)
tree3f515f5ab1ee7e7fca2374931fef262b4577e8ff /src/transport/gnunet-nat-client-windows.c
parent78f94904007317852f6a2016f9afe7483a22f4cd (diff)
downloadgnunet-192a6a6663b55a491987f8423c22527f12d1f46b.tar.gz
gnunet-192a6a6663b55a491987f8423c22527f12d1f46b.zip
windoze suckssss
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-rw-r--r--src/transport/gnunet-nat-client-windows.c457
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diff --git a/src/transport/gnunet-nat-client-windows.c b/src/transport/gnunet-nat-client-windows.c
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1/*
2 This file is part of GNUnet.
3 (C) 2010 Christian Grothoff (and other contributing authors)
4
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.
9
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.
14
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.
19*/
20
21/**
22 * @file src/transport/gnunet-nat-client-windows.c
23 * @brief Tool to help bypass NATs using ICMP method; must run as
24 * root (SUID will do) or administrator on W32
25 * This code will work under GNU/Linux or W32.
26 * @author Nathan Evans
27 *
28 * This program will send ONE ICMP message using RAW sockets
29 * to the IP address specified as the second argument. Since
30 * it uses RAW sockets, it must be installed SUID or run as 'root'.
31 * In order to keep the security risk of the resulting SUID binary
32 * minimal, the program ONLY opens the RAW socket with root
33 * privileges, then drops them and only then starts to process
34 * command line arguments. The code also does not link against
35 * any shared libraries (except libc) and is strictly minimal
36 * (except for checking for errors). The following list of people
37 * have reviewed this code and considered it safe since the last
38 * modification (if you reviewed it, please have your name added
39 * to the list):
40 *
41 * - Christian Grothoff
42 * - Nathan Evans
43 */
44#define _GNU_SOURCE
45#ifdef WIN32
46#include <winsock2.h>
47#else
48#include <sys/types.h>
49#include <sys/socket.h>
50#include <arpa/inet.h>
51#include <sys/select.h>
52#include <netinet/ip.h>
53#include <netinet/ip_icmp.h>
54#include <netinet/in.h>
55#endif
56#include <sys/time.h>
57#include <sys/types.h>
58#include <unistd.h>
59#include <stdio.h>
60#include <string.h>
61#include <errno.h>
62#include <stdlib.h>
63#include <stdint.h>
64#include <time.h>
65
66
67#ifdef WIN32
68typedef unsigned int uid_t;
69typedef SOCKET Socket;
70typedef unsigned short ushort;
71#define ICMP_ECHO 8
72#define IPDEFTTL 64 /* default ttl, from RFC 1340 */
73#define ICMP_TIME_EXCEEDED 11 /* Time Exceeded */
74#define IP_HDRINCL 3 /* int; Header is included with data. */
75#else
76typedef int Socket;
77#endif
78
79/**
80 * Must match IP given in the server.
81 */
82#define DUMMY_IP "192.0.2.86"
83
84#define NAT_TRAV_PORT 22225
85
86struct ip_packet
87{
88 uint8_t vers_ihl;
89 uint8_t tos;
90 uint16_t pkt_len;
91 uint16_t id;
92 uint16_t flags_frag_offset;
93 uint8_t ttl;
94 uint8_t proto;
95 uint16_t checksum;
96 uint32_t src_ip;
97 uint32_t dst_ip;
98};
99
100struct icmp_packet
101{
102 uint8_t type;
103 uint8_t code;
104 uint16_t checksum;
105 uint32_t reserved;
106
107};
108
109struct icmp_echo_packet
110{
111 uint8_t type;
112 uint8_t code;
113 uint16_t checksum;
114 uint32_t reserved;
115 uint32_t data;
116};
117
118struct udp_packet
119{
120 uint16_t src_port;
121
122 uint16_t dst_port;
123
124 uint32_t length;
125};
126
127static Socket rawsock;
128
129static struct in_addr dummy;
130
131static uint32_t port;
132
133#if WIN32
134/**
135 * @param af address family
136 * @param cp the address to print
137 * @param buf where to write the address result
138 */
139static int inet_pton (int af, char *cp, struct in_addr *buf)
140{
141 //ret = WSAStringToAddress (cp, af, NULL, (LPSOCKADDR)buf, &ssize);
142 buf->s_addr = inet_addr(cp);
143 if (buf->s_addr == INADDR_NONE)
144 {
145 fprintf(stderr, "Error %d handling address %s", WSAGetLastError(), cp);
146 return 0;
147 }
148 else
149 return 1;
150}
151#endif
152
153static uint16_t
154calc_checksum(const uint16_t *data,
155 unsigned int bytes)
156{
157 uint32_t sum;
158 unsigned int i;
159
160 sum = 0;
161 for (i=0;i<bytes/2;i++)
162 sum += data[i];
163 sum = (sum & 0xffff) + (sum >> 16);
164 sum = htons(0xffff - sum);
165 return sum;
166}
167
168
169static void
170make_echo (const struct in_addr *src_ip,
171 struct icmp_echo_packet *echo, uint32_t num)
172{
173 memset(echo, 0, sizeof(struct icmp_echo_packet));
174 echo->type = ICMP_ECHO;
175 echo->code = 0;
176 echo->reserved = 0;
177 echo->checksum = 0;
178 echo->data = htons(num);
179 echo->checksum = htons(calc_checksum((uint16_t*)echo,
180 sizeof (struct icmp_echo_packet)));
181}
182
183
184/**
185 * Send an ICMP message to the target.
186 *
187 * @param my_ip source address
188 * @param other target address
189 */
190static void
191send_icmp_udp (const struct in_addr *my_ip,
192 const struct in_addr *other)
193{
194 struct ip_packet ip_pkt;
195 struct icmp_packet icmp_pkt;
196 struct udp_packet udp_pkt;
197
198 struct sockaddr_in dst;
199 char packet[sizeof(ip_pkt) * 2 + sizeof(icmp_pkt) * 2 + sizeof(uint32_t)];
200
201 size_t off;
202 int err;
203
204 /* ip header: send to (known) ip address */
205 off = 0;
206 memset(&ip_pkt, 0, sizeof(ip_pkt));
207 ip_pkt.vers_ihl = 0x45;
208 ip_pkt.tos = 0;
209 ip_pkt.pkt_len = htons(sizeof (packet));
210 ip_pkt.id = htons(256);
211 ip_pkt.flags_frag_offset = 0;
212 ip_pkt.ttl = 128;
213 ip_pkt.proto = IPPROTO_ICMP;
214 ip_pkt.checksum = 0;
215 ip_pkt.src_ip = my_ip->s_addr;
216 ip_pkt.dst_ip = other->s_addr;
217 ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt, sizeof (ip_pkt)));
218 memcpy(&packet[off], &ip_pkt, sizeof(ip_pkt));
219 off += sizeof(ip_pkt);
220
221 /* ip header of the presumably 'lost' udp packet */
222 ip_pkt.vers_ihl = 0x45;
223 ip_pkt.tos = 0;
224 ip_pkt.pkt_len = (sizeof (struct ip_packet) + sizeof (struct icmp_echo_packet));
225
226 icmp_pkt.type = 11; /* TTL exceeded */
227 icmp_pkt.code = 0;
228 icmp_pkt.checksum = 0;
229 icmp_pkt.reserved = 0;
230 memcpy(&packet[off], &icmp_pkt, sizeof(icmp_pkt));
231 off += sizeof(icmp_pkt);
232
233 /* build inner IP header */
234 memset(&ip_pkt, 0, sizeof(ip_pkt));
235 ip_pkt.vers_ihl = 0x45;
236 ip_pkt.tos = 0;
237 ip_pkt.pkt_len = htons(sizeof (ip_pkt) + sizeof(udp_pkt));
238 ip_pkt.id = htons(0);
239 ip_pkt.flags_frag_offset = 0;
240 ip_pkt.ttl = 128;
241 ip_pkt.proto = IPPROTO_UDP;
242 ip_pkt.checksum = 0;
243 ip_pkt.src_ip = other->s_addr;
244 ip_pkt.dst_ip = dummy.s_addr;
245 ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt, sizeof (ip_pkt)));
246 memcpy(&packet[off], &ip_pkt, sizeof(ip_pkt));
247 off += sizeof(ip_pkt);
248
249 /* build UDP header */
250 udp_pkt.src_port = htons(NAT_TRAV_PORT); /* FIXME: does this port matter? */
251 udp_pkt.dst_port = htons(NAT_TRAV_PORT);
252
253 memset(&udp_pkt.length, 0, sizeof(uint32_t));
254 udp_pkt.length = htonl(port);
255 memcpy(&packet[off], &udp_pkt, sizeof(udp_pkt));
256 off += sizeof(udp_pkt);
257
258 /* set ICMP checksum */
259 icmp_pkt.checksum = htons(calc_checksum((uint16_t*)&packet[sizeof(ip_pkt)],
260 sizeof (icmp_pkt) + sizeof(ip_pkt) + sizeof(udp_pkt)));
261 memcpy (&packet[sizeof(ip_pkt)], &icmp_pkt, sizeof (icmp_pkt));
262
263
264 memset (&dst, 0, sizeof (dst));
265 dst.sin_family = AF_INET;
266 dst.sin_addr = *other;
267 err = sendto(rawsock,
268 packet,
269 off, 0,
270 (struct sockaddr*)&dst,
271 sizeof(dst));
272
273 if (err < 0)
274 {
275 fprintf(stderr,
276 "sendto failed: %s\n", strerror(errno));
277 }
278 else if (err != off)
279 {
280 fprintf(stderr,
281 "Error: partial send of ICMP message\n");
282 }
283}
284
285
286/**
287 * Send an ICMP message to the target.
288 *
289 * @param my_ip source address
290 * @param other target address
291 */
292static void
293send_icmp (const struct in_addr *my_ip,
294 const struct in_addr *other)
295{
296 struct ip_packet ip_pkt;
297 struct icmp_packet *icmp_pkt;
298 struct icmp_echo_packet icmp_echo;
299 struct sockaddr_in dst;
300 char packet[sizeof (struct ip_packet)*2 + sizeof (struct icmp_packet) + sizeof(struct icmp_echo_packet)];
301
302 size_t off;
303 int err;
304
305 /* ip header: send to (known) ip address */
306 off = 0;
307 memset(&ip_pkt, 0, sizeof(ip_pkt));
308 ip_pkt.vers_ihl = 0x45;
309 ip_pkt.tos = 0;
310 ip_pkt.pkt_len = sizeof (packet); /* huh? */
311 ip_pkt.id = 1;
312 ip_pkt.flags_frag_offset = 0;
313 ip_pkt.ttl = IPDEFTTL;
314 ip_pkt.proto = IPPROTO_ICMP;
315 ip_pkt.checksum = 0;
316 ip_pkt.src_ip = my_ip->s_addr;
317 ip_pkt.dst_ip = other->s_addr;
318 ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt, sizeof (struct ip_packet)));
319 memcpy (packet, &ip_pkt, sizeof (struct ip_packet));
320 off += sizeof (ip_pkt);
321 /* icmp reply: time exceeded */
322 icmp_pkt = (struct icmp_packet*) &packet[off];
323 memset(icmp_pkt, 0, sizeof(struct icmp_packet));
324 icmp_pkt->type = ICMP_TIME_EXCEEDED;
325 icmp_pkt->code = 0;
326 icmp_pkt->reserved = 0;
327 icmp_pkt->checksum = 0;
328
329 off += sizeof (struct icmp_packet);
330
331 /* ip header of the presumably 'lost' udp packet */
332 ip_pkt.vers_ihl = 0x45;
333 ip_pkt.tos = 0;
334 ip_pkt.pkt_len = (sizeof (struct ip_packet) + sizeof (struct icmp_echo_packet));
335
336 ip_pkt.id = 1;
337 ip_pkt.flags_frag_offset = 0;
338 ip_pkt.ttl = 1; /* real TTL would be 1 on a time exceeded packet */
339 ip_pkt.proto = IPPROTO_ICMP;
340 ip_pkt.src_ip = other->s_addr;
341 ip_pkt.dst_ip = dummy.s_addr;
342 ip_pkt.checksum = 0;
343 ip_pkt.checksum = htons(calc_checksum((uint16_t*)&ip_pkt, sizeof (struct ip_packet)));
344 memcpy (&packet[off], &ip_pkt, sizeof (struct ip_packet));
345 off += sizeof (struct ip_packet);
346
347 make_echo (other, &icmp_echo, port);
348 memcpy (&packet[off], &icmp_echo, sizeof(struct icmp_echo_packet));
349 off += sizeof (struct icmp_echo_packet);
350
351 icmp_pkt->checksum = htons(calc_checksum((uint16_t*)icmp_pkt,
352 sizeof (struct icmp_packet) + sizeof(struct ip_packet) + sizeof(struct icmp_echo_packet)));
353
354 memset (&dst, 0, sizeof (dst));
355 dst.sin_family = AF_INET;
356 dst.sin_addr = *other;
357 err = sendto(rawsock,
358 packet,
359 off, 0,
360 (struct sockaddr*)&dst,
361 sizeof(dst)); /* or sizeof 'struct sockaddr'? */
362 if (err < 0)
363 {
364 fprintf(stderr,
365 "sendto failed: %s\n", strerror(errno));
366 }
367 else if (err != off)
368 {
369 fprintf(stderr,
370 "Error: partial send of ICMP message\n");
371 }
372}
373
374
375static Socket
376make_raw_socket ()
377{
378 const int one = 1;
379 int ret;
380
381 ret = socket (AF_INET, SOCK_RAW, IPPROTO_RAW);
382 if (-1 == ret)
383 {
384 fprintf (stderr,
385 "Error opening RAW socket: %s\n",
386 strerror (errno));
387 return -1;
388 }
389 if (setsockopt(ret, SOL_SOCKET, SO_BROADCAST,
390 (char *)&one, sizeof(one)) == -1)
391 fprintf(stderr,
392 "setsockopt failed: %s\n",
393 strerror (errno));
394 if (setsockopt(ret, IPPROTO_IP, IP_HDRINCL,
395 (char *)&one, sizeof(one)) == -1)
396 fprintf(stderr,
397 "setsockopt failed: %s\n",
398 strerror (errno));
399 return ret;
400}
401
402
403int
404main (int argc, char *const *argv)
405{
406 struct in_addr external;
407 struct in_addr target;
408#ifndef WIN32
409 uid_t uid;
410#endif
411
412#ifdef WIN32
413 // WSA startup
414 WSADATA wsaData;
415 if (WSAStartup (MAKEWORD (2, 1), &wsaData) != 0)
416 {
417 fprintf (stderr, "Failed to find Winsock 2.1 or better.\n");
418 return 4; // ERROR
419 }
420#endif
421
422 if (-1 == (rawsock = make_raw_socket()))
423 return 1;
424
425#ifndef WIN32
426 uid = getuid ();
427 if (0 != setresuid (uid, uid, uid))
428 fprintf (stderr,
429 "Failed to setresuid: %s\n",
430 strerror (errno));
431#endif
432 if (argc != 4)
433 {
434 fprintf (stderr,
435 "This program must be started with our IP, the targets external IP, and our port as arguments.\n");
436 return 1;
437 }
438 port = atoi(argv[3]);
439
440 if ( (1 != inet_pton (AF_INET, argv[1], &external)) ||
441 (1 != inet_pton (AF_INET, argv[2], &target)) )
442 {
443 fprintf (stderr,
444 "Error parsing IPv4 address: %s\n",
445 strerror (errno));
446 return 1;
447 }
448 if (1 != inet_pton (AF_INET, DUMMY_IP, &dummy)) abort ();
449 send_icmp (&external,
450 &target);
451 send_icmp_udp (&external,
452 &target);
453 close (rawsock);
454 return 0;
455}
456
457/* end of gnunet-nat-client.c */