2 This file is part of GNUnet.
3 (C) 2010, 2012 Christian Grothoff
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-helper-vpn.c
23 * @brief the helper for the VPN service. Opens a virtual network-interface,
24 * sends data received on the if to stdout, sends data received on stdin to the
26 * @author Philipp Tölke
27 * @author Christian Grothoff
29 * The following list of people have reviewed this code and considered
30 * it safe since the last modification (if you reviewed it, please
31 * have your name added to the list):
36 #include <linux/if_tun.h>
39 * Need 'struct GNUNET_MessageHeader'.
41 #include "gnunet_crypto_lib.h"
42 #include "gnunet_common.h"
45 * Need VPN message types.
47 #include "gnunet_protocols.h"
50 * Should we print (interesting|debug) messages that can happen during
53 #define DEBUG GNUNET_NO
56 * Maximum size of a GNUnet message (GNUNET_SERVER_MAX_MESSAGE_SIZE)
58 #define MAX_SIZE 65536
62 * This is in linux/include/net/ipv6.h, but not always exported...
66 struct in6_addr ifr6_addr;
67 uint32_t ifr6_prefixlen;
68 unsigned int ifr6_ifindex;
74 * Creates a tun-interface called dev;
76 * @param dev is asumed to point to a char[IFNAMSIZ]
77 * if *dev == '\\0', uses the name supplied by the kernel;
78 * @return the fd to the tun or -1 on error
92 if (-1 == (fd = open ("/dev/net/tun", O_RDWR)))
94 fprintf (stderr, "Error opening `%s': %s\n", "/dev/net/tun",
101 fprintf (stderr, "File descriptor to large: %d", fd);
106 memset (&ifr, 0, sizeof (ifr));
107 ifr.ifr_flags = IFF_TUN;
110 strncpy (ifr.ifr_name, dev, IFNAMSIZ);
112 if (-1 == ioctl (fd, TUNSETIFF, (void *) &ifr))
114 fprintf (stderr, "Error with ioctl on `%s': %s\n", "/dev/net/tun",
119 strcpy (dev, ifr.ifr_name);
125 * @brief Sets the IPv6-Address given in address on the interface dev
127 * @param dev the interface to configure
128 * @param address the IPv6-Address
129 * @param prefix_len the length of the network-prefix
132 set_address6 (const char *dev, const char *address, unsigned long prefix_len)
135 struct in6_ifreq ifr6;
136 struct sockaddr_in6 sa6;
140 * parse the new address
142 memset (&sa6, 0, sizeof (struct sockaddr_in6));
143 sa6.sin6_family = AF_INET6;
144 if (1 != inet_pton (AF_INET6, address, sa6.sin6_addr.s6_addr))
146 fprintf (stderr, "Failed to parse address `%s': %s\n", address,
151 if (-1 == (fd = socket (PF_INET6, SOCK_DGRAM, 0)))
153 fprintf (stderr, "Error creating socket: %s\n", strerror (errno));
157 memset (&ifr, 0, sizeof (struct ifreq));
159 * Get the index of the if
161 strncpy (ifr.ifr_name, dev, IFNAMSIZ);
162 if (-1 == ioctl (fd, SIOGIFINDEX, &ifr))
164 fprintf (stderr, "ioctl failed at %d: %s\n", __LINE__, strerror (errno));
169 memset (&ifr6, 0, sizeof (struct in6_ifreq));
170 ifr6.ifr6_addr = sa6.sin6_addr;
171 ifr6.ifr6_ifindex = ifr.ifr_ifindex;
172 ifr6.ifr6_prefixlen = prefix_len;
177 if (-1 == ioctl (fd, SIOCSIFADDR, &ifr6))
179 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
188 if (-1 == ioctl (fd, SIOCGIFFLAGS, &ifr))
190 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
197 * Add the UP and RUNNING flags
199 ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
200 if (-1 == ioctl (fd, SIOCSIFFLAGS, &ifr))
202 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
210 fprintf (stderr, "close failed: %s\n", strerror (errno));
217 * @brief Sets the IPv4-Address given in address on the interface dev
219 * @param dev the interface to configure
220 * @param address the IPv4-Address
221 * @param mask the netmask
224 set_address4 (const char *dev, const char *address, const char *mask)
227 struct sockaddr_in *addr;
230 memset (&ifr, 0, sizeof (struct ifreq));
231 addr = (struct sockaddr_in *) &(ifr.ifr_addr);
232 addr->sin_family = AF_INET;
237 if (1 != inet_pton (AF_INET, address, &addr->sin_addr.s_addr))
239 fprintf (stderr, "Failed to parse address `%s': %s\n", address,
244 if (-1 == (fd = socket (PF_INET, SOCK_DGRAM, 0)))
246 fprintf (stderr, "Error creating socket: %s\n", strerror (errno));
250 strncpy (ifr.ifr_name, dev, IFNAMSIZ);
255 if (-1 == ioctl (fd, SIOCSIFADDR, &ifr))
257 fprintf (stderr, "ioctl failed at %d: %s\n", __LINE__, strerror (errno));
265 addr = (struct sockaddr_in *) &(ifr.ifr_netmask);
266 if (1 != inet_pton (AF_INET, mask, &addr->sin_addr.s_addr))
268 fprintf (stderr, "Failed to parse address `%s': %s\n", mask,
277 if (-1 == ioctl (fd, SIOCSIFNETMASK, &ifr))
279 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
288 if (-1 == ioctl (fd, SIOCGIFFLAGS, &ifr))
290 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
297 * Add the UP and RUNNING flags
299 ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
300 if (-1 == ioctl (fd, SIOCSIFFLAGS, &ifr))
302 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
310 fprintf (stderr, "close failed: %s\n", strerror (errno));
318 * Start forwarding to and from the tunnel.
320 * @param fd_tun tunnel FD
326 * The buffer filled by reading from fd_tun
328 unsigned char buftun[MAX_SIZE];
329 ssize_t buftun_size = 0;
330 unsigned char *buftun_read = NULL;
333 * The buffer filled by reading from stdin
335 unsigned char bufin[MAX_SIZE];
336 ssize_t bufin_size = 0;
337 size_t bufin_rpos = 0;
338 unsigned char *bufin_read = NULL;
343 /* read refers to reading from fd_tun, writing to stdout */
346 /* write refers to reading from stdin, writing to fd_tun */
349 while ((1 == read_open) || (1 == write_open))
355 * We are supposed to read and the buffer is empty
356 * -> select on read from tun
358 if (read_open && (0 == buftun_size))
359 FD_SET (fd_tun, &fds_r);
362 * We are supposed to read and the buffer is not empty
363 * -> select on write to stdout
365 if (read_open && (0 != buftun_size))
369 * We are supposed to write and the buffer is empty
370 * -> select on read from stdin
372 if (write_open && (NULL == bufin_read))
376 * We are supposed to write and the buffer is not empty
377 * -> select on write to tun
379 if (write_open && (NULL != bufin_read))
380 FD_SET (fd_tun, &fds_w);
382 int r = select (fd_tun + 1, &fds_r, &fds_w, NULL, NULL);
388 fprintf (stderr, "select failed: %s\n", strerror (errno));
394 if (FD_ISSET (fd_tun, &fds_r))
397 read (fd_tun, buftun + sizeof (struct GNUNET_MessageHeader),
398 MAX_SIZE - sizeof (struct GNUNET_MessageHeader));
399 if (-1 == buftun_size)
401 fprintf (stderr, "read-error: %s\n", strerror (errno));
402 shutdown (fd_tun, SHUT_RD);
403 shutdown (1, SHUT_WR);
407 else if (0 == buftun_size)
409 fprintf (stderr, "EOF on tun\n");
410 shutdown (fd_tun, SHUT_RD);
411 shutdown (1, SHUT_WR);
417 buftun_read = buftun;
418 struct GNUNET_MessageHeader *hdr =
419 (struct GNUNET_MessageHeader *) buftun;
420 buftun_size += sizeof (struct GNUNET_MessageHeader);
421 hdr->type = htons (GNUNET_MESSAGE_TYPE_VPN_HELPER);
422 hdr->size = htons (buftun_size);
425 else if (FD_ISSET (1, &fds_w))
427 ssize_t written = write (1, buftun_read, buftun_size);
434 fprintf (stderr, "write-error to stdout: %s\n", strerror (errno));
435 shutdown (fd_tun, SHUT_RD);
436 shutdown (1, SHUT_WR);
440 else if (0 == written)
442 fprintf (stderr, "write returned 0!?\n");
447 buftun_size -= written;
448 buftun_read += written;
452 if (FD_ISSET (0, &fds_r))
454 bufin_size = read (0, bufin + bufin_rpos, MAX_SIZE - bufin_rpos);
455 if (-1 == bufin_size)
457 fprintf (stderr, "read-error: %s\n", strerror (errno));
458 shutdown (0, SHUT_RD);
459 shutdown (fd_tun, SHUT_WR);
463 else if (0 == bufin_size)
466 fprintf (stderr, "EOF on stdin\n");
468 shutdown (0, SHUT_RD);
469 shutdown (fd_tun, SHUT_WR);
475 struct GNUNET_MessageHeader *hdr;
478 bufin_rpos += bufin_size;
479 if (bufin_rpos < sizeof (struct GNUNET_MessageHeader))
481 hdr = (struct GNUNET_MessageHeader *) bufin;
482 if (ntohs (hdr->type) != GNUNET_MESSAGE_TYPE_VPN_HELPER)
484 fprintf (stderr, "protocol violation!\n");
487 if (ntohs (hdr->size) > bufin_rpos)
489 bufin_read = bufin + sizeof (struct GNUNET_MessageHeader);
490 bufin_size = ntohs (hdr->size) - sizeof (struct GNUNET_MessageHeader);
491 bufin_rpos -= bufin_size + sizeof (struct GNUNET_MessageHeader);
494 else if (FD_ISSET (fd_tun, &fds_w))
496 ssize_t written = write (fd_tun, bufin_read, bufin_size);
500 fprintf (stderr, "write-error to tun: %s\n", strerror (errno));
501 shutdown (0, SHUT_RD);
502 shutdown (fd_tun, SHUT_WR);
506 else if (0 == written)
508 fprintf (stderr, "write returned 0!?\n");
513 bufin_size -= written;
514 bufin_read += written;
517 memmove (bufin, bufin_read, bufin_rpos);
518 bufin_read = NULL; /* start reading again */
530 * Open VPN tunnel interface.
532 * @param argc must be 6
533 * @param argv 0: binary name (gnunet-helper-vpn)
534 * 1: tunnel interface name (gnunet-vpn)
535 * 2: IPv6 address (::1), "-" to disable
536 * 3: IPv6 netmask length in bits (64), ignored if #2 is "-"
537 * 4: IPv4 address (1.2.3.4), "-" to disable
538 * 5: IPv4 netmask (255.255.0.0), ignored if #4 is "-"
541 main (int argc, char **argv)
549 fprintf (stderr, "Fatal: must supply 5 arguments!\n");
553 strncpy (dev, argv[1], IFNAMSIZ);
554 dev[IFNAMSIZ - 1] = '\0';
556 if (-1 == (fd_tun = init_tun (dev)))
558 fprintf (stderr, "Fatal: could not initialize tun-interface `%s' with IPv6 %s/%s and IPv4 %s/%s\n",
567 if (0 != strcmp (argv[2], "-"))
569 const char *address = argv[2];
570 long prefix_len = atol (argv[3]);
572 if ((prefix_len < 1) || (prefix_len > 127))
574 fprintf (stderr, "Fatal: prefix_len out of range\n");
578 set_address6 (dev, address, prefix_len);
581 if (0 != strcmp (argv[4], "-"))
583 const char *address = argv[4];
584 const char *mask = argv[5];
586 set_address4 (dev, address, mask);
589 uid_t uid = getuid ();
590 #ifdef HAVE_SETRESUID
591 if (0 != setresuid (uid, uid, uid))
593 fprintf (stderr, "Failed to setresuid: %s\n", strerror (errno));
598 if (0 != (setuid (uid) | seteuid (uid)))
600 fprintf (stderr, "Failed to setuid: %s\n", strerror (errno));
606 if (SIG_ERR == signal (SIGPIPE, SIG_IGN))
608 fprintf (stderr, "Failed to protect against SIGPIPE: %s\n",
610 /* no exit, we might as well die with SIGPIPE should it ever happen */