2 This file is part of GNUnet.
3 (C) 2010 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-daemon-vpn.c
23 * @brief the helper for various vpn-daemons. 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
28 * The following list of people have reviewed this code and considered
29 * it safe since the last modification (if you reviewed it, please
30 * have your name added to the list):
35 #include <linux/if_tun.h>
38 * Need 'struct GNUNET_MessageHeader'.
40 #include "gnunet_common.h"
43 * Need VPN message types.
45 #include "gnunet_protocols.h"
48 * Should we print (interesting|debug) messages that can happen during
51 #define DEBUG GNUNET_NO
54 * Maximum size of a GNUnet message (GNUNET_SERVER_MAX_MESSAGE_SIZE)
56 #define MAX_SIZE 65536
60 * This is in linux/include/net/ipv6.h, but not always exported...
64 struct in6_addr ifr6_addr;
65 uint32_t ifr6_prefixlen;
66 unsigned int ifr6_ifindex;
72 * Creates a tun-interface called dev;
74 * @param dev is asumed to point to a char[IFNAMSIZ]
75 * if *dev == '\\0', uses the name supplied by the kernel;
76 * @return the fd to the tun or -1 on error
90 if (-1 == (fd = open ("/dev/net/tun", O_RDWR)))
92 fprintf (stderr, "Error opening `%s': %s\n", "/dev/net/tun",
99 fprintf (stderr, "File descriptor to large: %d", fd);
104 memset (&ifr, 0, sizeof (ifr));
105 ifr.ifr_flags = IFF_TUN;
108 strncpy (ifr.ifr_name, dev, IFNAMSIZ);
110 if (-1 == ioctl (fd, TUNSETIFF, (void *) &ifr))
112 fprintf (stderr, "Error with ioctl on `%s': %s\n", "/dev/net/tun",
117 strcpy (dev, ifr.ifr_name);
123 * @brief Sets the IPv6-Address given in address on the interface dev
125 * @param dev the interface to configure
126 * @param address the IPv6-Address
127 * @param prefix_len the length of the network-prefix
130 set_address6 (const char *dev, const char *address, unsigned long prefix_len)
133 struct in6_ifreq ifr6;
134 struct sockaddr_in6 sa6;
138 * parse the new address
140 memset (&sa6, 0, sizeof (struct sockaddr_in6));
141 sa6.sin6_family = AF_INET6;
142 if (1 != inet_pton (AF_INET6, address, sa6.sin6_addr.s6_addr))
144 fprintf (stderr, "Failed to parse address `%s': %s\n", address,
149 if (-1 == (fd = socket (PF_INET6, SOCK_DGRAM, 0)))
151 fprintf (stderr, "Error creating socket: %s\n", strerror (errno));
155 memset (&ifr, 0, sizeof (struct ifreq));
157 * Get the index of the if
159 strncpy (ifr.ifr_name, dev, IFNAMSIZ);
160 if (-1 == ioctl (fd, SIOGIFINDEX, &ifr))
162 fprintf (stderr, "ioctl failed at %d: %s\n", __LINE__, strerror (errno));
167 memset (&ifr6, 0, sizeof (struct in6_ifreq));
168 ifr6.ifr6_addr = sa6.sin6_addr;
169 ifr6.ifr6_ifindex = ifr.ifr_ifindex;
170 ifr6.ifr6_prefixlen = prefix_len;
175 if (-1 == ioctl (fd, SIOCSIFADDR, &ifr6))
177 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
186 if (-1 == ioctl (fd, SIOCGIFFLAGS, &ifr))
188 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
195 * Add the UP and RUNNING flags
197 ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
198 if (-1 == ioctl (fd, SIOCSIFFLAGS, &ifr))
200 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
208 fprintf (stderr, "close failed: %s\n", strerror (errno));
215 * @brief Sets the IPv4-Address given in address on the interface dev
217 * @param dev the interface to configure
218 * @param address the IPv4-Address
219 * @param mask the netmask
222 set_address4 (const char *dev, const char *address, const char *mask)
225 struct sockaddr_in *addr;
228 memset (&ifr, 0, sizeof (struct ifreq));
229 addr = (struct sockaddr_in *) &(ifr.ifr_addr);
230 addr->sin_family = AF_INET;
235 if (1 != inet_pton (AF_INET, address, &addr->sin_addr.s_addr))
237 fprintf (stderr, "Failed to parse address `%s': %s\n", address,
242 if (-1 == (fd = socket (PF_INET, SOCK_DGRAM, 0)))
244 fprintf (stderr, "Error creating socket: %s\n", strerror (errno));
248 strncpy (ifr.ifr_name, dev, IFNAMSIZ);
253 if (-1 == ioctl (fd, SIOCSIFADDR, &ifr))
255 fprintf (stderr, "ioctl failed at %d: %s\n", __LINE__, strerror (errno));
263 addr = (struct sockaddr_in *) &(ifr.ifr_netmask);
264 if (1 != inet_pton (AF_INET, mask, &addr->sin_addr.s_addr))
266 fprintf (stderr, "Failed to parse address `%s': %s\n", mask,
275 if (-1 == ioctl (fd, SIOCSIFNETMASK, &ifr))
277 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
286 if (-1 == ioctl (fd, SIOCGIFFLAGS, &ifr))
288 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
295 * Add the UP and RUNNING flags
297 ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
298 if (-1 == ioctl (fd, SIOCSIFFLAGS, &ifr))
300 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
308 fprintf (stderr, "close failed: %s\n", strerror (errno));
316 * Start forwarding to and from the tunnel.
318 * @param fd_tun tunnel FD
324 * The buffer filled by reading from fd_tun
326 unsigned char buftun[MAX_SIZE];
327 ssize_t buftun_size = 0;
328 unsigned char *buftun_read = NULL;
331 * The buffer filled by reading from stdin
333 unsigned char bufin[MAX_SIZE];
334 ssize_t bufin_size = 0;
335 size_t bufin_rpos = 0;
336 unsigned char *bufin_read = NULL;
341 /* read refers to reading from fd_tun, writing to stdout */
344 /* write refers to reading from stdin, writing to fd_tun */
347 while ((1 == read_open) || (1 == write_open))
353 * We are supposed to read and the buffer is empty
354 * -> select on read from tun
356 if (read_open && (0 == buftun_size))
357 FD_SET (fd_tun, &fds_r);
360 * We are supposed to read and the buffer is not empty
361 * -> select on write to stdout
363 if (read_open && (0 != buftun_size))
367 * We are supposed to write and the buffer is empty
368 * -> select on read from stdin
370 if (write_open && (NULL == bufin_read))
374 * We are supposed to write and the buffer is not empty
375 * -> select on write to tun
377 if (write_open && (NULL != bufin_read))
378 FD_SET (fd_tun, &fds_w);
380 int r = select (fd_tun + 1, &fds_r, &fds_w, NULL, NULL);
386 fprintf (stderr, "select failed: %s\n", strerror (errno));
392 if (FD_ISSET (fd_tun, &fds_r))
395 read (fd_tun, buftun + sizeof (struct GNUNET_MessageHeader),
396 MAX_SIZE - sizeof (struct GNUNET_MessageHeader));
397 if (-1 == buftun_size)
399 fprintf (stderr, "read-error: %s\n", strerror (errno));
400 shutdown (fd_tun, SHUT_RD);
401 shutdown (1, SHUT_WR);
405 else if (0 == buftun_size)
407 fprintf (stderr, "EOF on tun\n");
408 shutdown (fd_tun, SHUT_RD);
409 shutdown (1, SHUT_WR);
415 buftun_read = buftun;
416 struct GNUNET_MessageHeader *hdr =
417 (struct GNUNET_MessageHeader *) buftun;
418 buftun_size += sizeof (struct GNUNET_MessageHeader);
419 hdr->type = htons (GNUNET_MESSAGE_TYPE_VPN_HELPER);
420 hdr->size = htons (buftun_size);
423 else if (FD_ISSET (1, &fds_w))
425 ssize_t written = write (1, buftun_read, buftun_size);
432 fprintf (stderr, "write-error to stdout: %s\n", strerror (errno));
433 shutdown (fd_tun, SHUT_RD);
434 shutdown (1, SHUT_WR);
438 else if (0 == written)
440 fprintf (stderr, "write returned 0!?\n");
445 buftun_size -= written;
446 buftun_read += written;
450 if (FD_ISSET (0, &fds_r))
452 bufin_size = read (0, bufin + bufin_rpos, MAX_SIZE - bufin_rpos);
453 if (-1 == bufin_size)
455 fprintf (stderr, "read-error: %s\n", strerror (errno));
456 shutdown (0, SHUT_RD);
457 shutdown (fd_tun, SHUT_WR);
461 else if (0 == bufin_size)
464 fprintf (stderr, "EOF on stdin\n");
466 shutdown (0, SHUT_RD);
467 shutdown (fd_tun, SHUT_WR);
473 struct GNUNET_MessageHeader *hdr;
476 bufin_rpos += bufin_size;
477 if (bufin_rpos < sizeof (struct GNUNET_MessageHeader))
479 hdr = (struct GNUNET_MessageHeader *) bufin;
480 if (ntohs (hdr->type) != GNUNET_MESSAGE_TYPE_VPN_HELPER)
482 fprintf (stderr, "protocol violation!\n");
485 if (ntohs (hdr->size) > bufin_rpos)
487 bufin_read = bufin + sizeof (struct GNUNET_MessageHeader);
488 bufin_size = ntohs (hdr->size) - sizeof (struct GNUNET_MessageHeader);
489 bufin_rpos -= bufin_size + sizeof (struct GNUNET_MessageHeader);
492 else if (FD_ISSET (fd_tun, &fds_w))
494 ssize_t written = write (fd_tun, bufin_read, bufin_size);
498 fprintf (stderr, "write-error to tun: %s\n", strerror (errno));
499 shutdown (0, SHUT_RD);
500 shutdown (fd_tun, SHUT_WR);
504 else if (0 == written)
506 fprintf (stderr, "write returned 0!?\n");
511 bufin_size -= written;
512 bufin_read += written;
515 memmove (bufin, bufin_read, bufin_rpos);
516 bufin_read = NULL; /* start reading again */
528 * Open VPN tunnel interface.
530 * @param argc must be 6
531 * @param argv 0: binary name (gnunet-helper-vpn)
532 * 1: tunnel interface name (gnunet-vpn)
533 * 2: IPv6 address (::1), "-" to disable
534 * 3: IPv6 netmask length in bits (64), ignored if #2 is "-"
535 * 4: IPv4 address (1.2.3.4), "-" to disable
536 * 5: IPv4 netmask (255.255.0.0), ignored if #4 is "-"
539 main (int argc, char **argv)
547 fprintf (stderr, "Fatal: must supply 5 arguments!\n");
551 strncpy (dev, argv[1], IFNAMSIZ);
552 dev[IFNAMSIZ - 1] = '\0';
554 if (-1 == (fd_tun = init_tun (dev)))
556 fprintf (stderr, "Fatal: could not initialize tun-interface `%s' with IPv6 %s/%s and IPv4 %s/%s\n",
565 if (0 != strcmp (argv[2], "-"))
567 const char *address = argv[2];
568 long prefix_len = atol (argv[3]);
570 if ((prefix_len < 1) || (prefix_len > 127))
572 fprintf (stderr, "Fatal: prefix_len out of range\n");
576 set_address6 (dev, address, prefix_len);
579 if (0 != strcmp (argv[4], "-"))
581 const char *address = argv[4];
582 const char *mask = argv[5];
584 set_address4 (dev, address, mask);
587 uid_t uid = getuid ();
588 #ifdef HAVE_SETRESUID
589 if (0 != setresuid (uid, uid, uid))
591 fprintf (stderr, "Failed to setresuid: %s\n", strerror (errno));
596 if (0 != (setuid (uid) | seteuid (uid)))
598 fprintf (stderr, "Failed to setuid: %s\n", strerror (errno));
604 if (SIG_ERR == signal (SIGPIPE, SIG_IGN))
606 fprintf (stderr, "Failed to protect against SIGPIPE: %s\n",
608 /* no exit, we might as well die with SIGPIPE should it ever happen */