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 * Maximum size of a GNUnet message (GNUNET_SERVER_MAX_MESSAGE_SIZE)
50 #define MAX_SIZE 65536
54 * This is in linux/include/net/ipv6.h, but not always exported...
58 struct in6_addr ifr6_addr;
59 uint32_t ifr6_prefixlen;
60 unsigned int ifr6_ifindex;
66 * Creates a tun-interface called dev;
68 * @param dev is asumed to point to a char[IFNAMSIZ]
69 * if *dev == '\\0', uses the name supplied by the kernel;
70 * @return the fd to the tun or -1 on error
84 if (-1 == (fd = open ("/dev/net/tun", O_RDWR)))
86 fprintf (stderr, "Error opening `%s': %s\n", "/dev/net/tun",
93 fprintf (stderr, "File descriptor to large: %d", fd);
97 memset (&ifr, 0, sizeof (ifr));
98 ifr.ifr_flags = IFF_TUN;
101 strncpy (ifr.ifr_name, dev, IFNAMSIZ);
103 if (-1 == ioctl (fd, TUNSETIFF, (void *) &ifr))
105 fprintf (stderr, "Error with ioctl on `%s': %s\n", "/dev/net/tun",
110 strcpy (dev, ifr.ifr_name);
116 * @brief Sets the IPv6-Address given in address on the interface dev
118 * @param dev the interface to configure
119 * @param address the IPv6-Address
120 * @param prefix_len the length of the network-prefix
123 set_address6 (const char *dev, const char *address, unsigned long prefix_len)
126 struct in6_ifreq ifr6;
127 struct sockaddr_in6 sa6;
131 * parse the new address
133 memset (&sa6, 0, sizeof (struct sockaddr_in6));
134 sa6.sin6_family = AF_INET6;
135 if (1 != inet_pton (AF_INET6, address, sa6.sin6_addr.s6_addr))
137 fprintf (stderr, "Failed to parse address `%s': %s\n", address,
142 if (-1 == (fd = socket (PF_INET6, SOCK_DGRAM, 0)))
144 fprintf (stderr, "Error creating socket: %s\n", strerror (errno));
148 memset (&ifr, 0, sizeof (struct ifreq));
150 * Get the index of the if
152 strncpy (ifr.ifr_name, dev, IFNAMSIZ);
153 if (-1 == ioctl (fd, SIOGIFINDEX, &ifr))
155 fprintf (stderr, "ioctl failed at %d: %s\n", __LINE__, strerror (errno));
160 memset (&ifr6, 0, sizeof (struct in6_ifreq));
161 ifr6.ifr6_addr = sa6.sin6_addr;
162 ifr6.ifr6_ifindex = ifr.ifr_ifindex;
163 ifr6.ifr6_prefixlen = prefix_len;
168 if (-1 == ioctl (fd, SIOCSIFADDR, &ifr6))
170 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
179 if (-1 == ioctl (fd, SIOCGIFFLAGS, &ifr))
181 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
188 * Add the UP and RUNNING flags
190 ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
191 if (-1 == ioctl (fd, SIOCSIFFLAGS, &ifr))
193 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
201 fprintf (stderr, "close failed: %s\n", strerror (errno));
208 * @brief Sets the IPv4-Address given in address on the interface dev
210 * @param dev the interface to configure
211 * @param address the IPv4-Address
212 * @param mask the netmask
215 set_address4 (const char *dev, const char *address, const char *mask)
218 struct sockaddr_in *addr;
221 memset (&ifr, 0, sizeof (struct ifreq));
222 addr = (struct sockaddr_in *) &(ifr.ifr_addr);
223 addr->sin_family = AF_INET;
228 if (1 != inet_pton (AF_INET, address, &addr->sin_addr.s_addr))
230 fprintf (stderr, "Failed to parse address `%s': %s\n", address,
235 if (-1 == (fd = socket (PF_INET, SOCK_DGRAM, 0)))
237 fprintf (stderr, "Error creating socket: %s\n", strerror (errno));
241 strncpy (ifr.ifr_name, dev, IFNAMSIZ);
246 if (-1 == ioctl (fd, SIOCSIFADDR, &ifr))
248 fprintf (stderr, "ioctl failed at %d: %s\n", __LINE__, strerror (errno));
256 addr = (struct sockaddr_in *) &(ifr.ifr_netmask);
257 if (1 != inet_pton (AF_INET, mask, &addr->sin_addr.s_addr))
259 fprintf (stderr, "Failed to parse address `%s': %s\n", mask,
268 if (-1 == ioctl (fd, SIOCSIFNETMASK, &ifr))
270 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
279 if (-1 == ioctl (fd, SIOCGIFFLAGS, &ifr))
281 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
288 * Add the UP and RUNNING flags
290 ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
291 if (-1 == ioctl (fd, SIOCSIFFLAGS, &ifr))
293 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
301 fprintf (stderr, "close failed: %s\n", strerror (errno));
309 * Start forwarding to and from the tunnel.
311 * @param fd_tun tunnel FD
317 * The buffer filled by reading from fd_tun
319 unsigned char buftun[MAX_SIZE];
320 ssize_t buftun_size = 0;
321 unsigned char *buftun_read = NULL;
324 * The buffer filled by reading from stdin
326 unsigned char bufin[MAX_SIZE];
327 ssize_t bufin_size = 0;
328 size_t bufin_rpos = 0;
329 unsigned char *bufin_read = NULL;
334 /* read refers to reading from fd_tun, writing to stdout */
337 /* write refers to reading from stdin, writing to fd_tun */
340 while ((1 == read_open) || (1 == write_open))
346 * We are supposed to read and the buffer is empty
347 * -> select on read from tun
349 if (read_open && (0 == buftun_size))
350 FD_SET (fd_tun, &fds_r);
353 * We are supposed to read and the buffer is not empty
354 * -> select on write to stdout
356 if (read_open && (0 != buftun_size))
360 * We are supposed to write and the buffer is empty
361 * -> select on read from stdin
363 if (write_open && (NULL == bufin_read))
367 * We are supposed to write and the buffer is not empty
368 * -> select on write to tun
370 if (write_open && (NULL != bufin_read))
371 FD_SET (fd_tun, &fds_w);
373 int r = select (fd_tun + 1, &fds_r, &fds_w, NULL, NULL);
379 fprintf (stderr, "select failed: %s\n", strerror (errno));
385 if (FD_ISSET (fd_tun, &fds_r))
388 read (fd_tun, buftun + sizeof (struct GNUNET_MessageHeader),
389 MAX_SIZE - sizeof (struct GNUNET_MessageHeader));
390 if (-1 == buftun_size)
392 fprintf (stderr, "read-error: %s\n", strerror (errno));
393 shutdown (fd_tun, SHUT_RD);
394 shutdown (1, SHUT_WR);
398 else if (0 == buftun_size)
400 fprintf (stderr, "EOF on tun\n");
401 shutdown (fd_tun, SHUT_RD);
402 shutdown (1, SHUT_WR);
408 buftun_read = buftun;
409 struct GNUNET_MessageHeader *hdr =
410 (struct GNUNET_MessageHeader *) buftun;
411 buftun_size += sizeof (struct GNUNET_MessageHeader);
412 hdr->type = htons (GNUNET_MESSAGE_TYPE_VPN_HELPER);
413 hdr->size = htons (buftun_size);
416 else if (FD_ISSET (1, &fds_w))
418 ssize_t written = write (1, buftun_read, buftun_size);
422 fprintf (stderr, "write-error to stdout: %s\n", strerror (errno));
423 shutdown (fd_tun, SHUT_RD);
424 shutdown (1, SHUT_WR);
428 else if (0 == written)
430 fprintf (stderr, "write returned 0!?\n");
435 buftun_size -= written;
436 buftun_read += written;
440 if (FD_ISSET (0, &fds_r))
442 bufin_size = read (0, bufin + bufin_rpos, MAX_SIZE - bufin_rpos);
443 if (-1 == bufin_size)
445 fprintf (stderr, "read-error: %s\n", strerror (errno));
446 shutdown (0, SHUT_RD);
447 shutdown (fd_tun, SHUT_WR);
451 else if (0 == bufin_size)
453 fprintf (stderr, "EOF on stdin\n");
454 shutdown (0, SHUT_RD);
455 shutdown (fd_tun, SHUT_WR);
461 struct GNUNET_MessageHeader *hdr;
464 bufin_rpos += bufin_size;
465 if (bufin_rpos < sizeof (struct GNUNET_MessageHeader))
467 hdr = (struct GNUNET_MessageHeader *) bufin;
468 if (ntohs (hdr->type) != GNUNET_MESSAGE_TYPE_VPN_HELPER)
470 fprintf (stderr, "protocol violation!\n");
473 if (ntohs (hdr->size) > bufin_rpos)
475 bufin_read = bufin + sizeof (struct GNUNET_MessageHeader);
476 bufin_size = ntohs (hdr->size) - sizeof (struct GNUNET_MessageHeader);
477 bufin_rpos -= bufin_size + sizeof (struct GNUNET_MessageHeader);
480 else if (FD_ISSET (fd_tun, &fds_w))
482 ssize_t written = write (fd_tun, bufin_read, bufin_size);
486 fprintf (stderr, "write-error to tun: %s\n", strerror (errno));
487 shutdown (0, SHUT_RD);
488 shutdown (fd_tun, SHUT_WR);
492 else if (0 == written)
494 fprintf (stderr, "write returned 0!?\n");
499 bufin_size -= written;
500 bufin_read += written;
503 memmove (bufin, bufin_read, bufin_rpos);
504 bufin_read = NULL; /* start reading again */
516 * Open VPN tunnel interface.
518 * @param argc must be 6
519 * @param argv 0: binary name (gnunet-helper-vpn)
520 * 1: tunnel interface name (gnunet-vpn)
521 * 2: IPv6 address (::1)
522 * 3: IPv6 netmask length in bits (64)
523 * 4: IPv4 address (1.2.3.4)
524 * 5: IPv4 netmask (255.255.0.0)
527 main (int argc, char **argv)
535 fprintf (stderr, "Fatal: must supply 5 arguments!\n");
539 strncpy (dev, argv[1], IFNAMSIZ);
540 dev[IFNAMSIZ - 1] = '\0';
542 if (-1 == (fd_tun = init_tun (dev)))
544 fprintf (stderr, "Fatal: could not initialize tun-interface\n");
549 const char *address = argv[2];
550 long prefix_len = atol (argv[3]);
552 if ((prefix_len < 1) || (prefix_len > 127))
554 fprintf (stderr, "Fatal: prefix_len out of range\n");
558 set_address6 (dev, address, prefix_len);
562 const char *address = argv[4];
563 const char *mask = argv[5];
565 set_address4 (dev, address, mask);
568 uid_t uid = getuid ();
569 #ifdef HAVE_SETRESUID
570 if (0 != setresuid (uid, uid, uid))
572 fprintf (stderr, "Failed to setresuid: %s\n", strerror (errno));
577 if (0 != (setuid (uid) | seteuid (uid)))
579 fprintf (stderr, "Failed to setuid: %s\n", strerror (errno));
585 if (SIG_ERR == signal (SIGPIPE, SIG_IGN))
587 fprintf (stderr, "Failed to protect against SIGPIPE: %s\n",
589 /* no exit, we might as well die with SIGPIPE should it ever happen */