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;
65 * Creates a tun-interface called dev;
66 * @param dev is asumed to point to a char[IFNAMSIZ]
67 * if *dev == '\\0', uses the name supplied by the kernel
68 * @return the fd to the tun or -1 on error
82 if (-1 == (fd = open ("/dev/net/tun", O_RDWR)))
84 fprintf (stderr, "Error opening `%s': %s\n", "/dev/net/tun",
91 fprintf (stderr, "File descriptor to large: %d", fd);
95 memset (&ifr, 0, sizeof (ifr));
96 ifr.ifr_flags = IFF_TUN;
99 strncpy (ifr.ifr_name, dev, IFNAMSIZ);
101 if (-1 == ioctl (fd, TUNSETIFF, (void *) &ifr))
103 fprintf (stderr, "Error with ioctl on `%s': %s\n", "/dev/net/tun",
108 strcpy (dev, ifr.ifr_name);
114 * @brief Sets the IPv6-Address given in address on the interface dev
116 * @param dev the interface to configure
117 * @param address the IPv6-Address
118 * @param prefix_len the length of the network-prefix
121 set_address6 (const char *dev, const char *address, unsigned long prefix_len)
124 struct in6_ifreq ifr6;
125 struct sockaddr_in6 sa6;
129 * parse the new address
131 memset (&sa6, 0, sizeof (struct sockaddr_in6));
132 if (1 != inet_pton (AF_INET6, address, sa6.sin6_addr.s6_addr))
134 fprintf (stderr, "Failed to parse address `%s': %s\n", address,
139 if (-1 == (fd = socket (PF_INET6, SOCK_DGRAM, 0)))
141 fprintf (stderr, "Error creating socket: %s\n", strerror (errno));
145 sa6.sin6_family = AF_INET6;
146 memcpy (&ifr6.ifr6_addr, &sa6.sin6_addr, sizeof (struct in6_addr));
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));
158 ifr6.ifr6_ifindex = ifr.ifr_ifindex;
160 ifr6.ifr6_prefixlen = prefix_len;
165 if (-1 == ioctl (fd, SIOCSIFADDR, &ifr6))
167 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
175 if (-1 == ioctl (fd, SIOCGIFFLAGS, &ifr))
177 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
183 * Add the UP and RUNNING flags
185 ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
186 if (-1 == ioctl (fd, SIOCSIFFLAGS, &ifr))
188 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
195 fprintf (stderr, "close failed: %s\n", strerror (errno));
202 * @brief Sets the IPv4-Address given in address on the interface dev
204 * @param dev the interface to configure
205 * @param address the IPv4-Address
206 * @param mask the netmask
209 set_address4 (const char *dev, const char *address, const char *mask)
212 struct sockaddr_in *addr;
215 memset (&ifr, 0, sizeof (struct ifreq));
216 addr = (struct sockaddr_in *) &(ifr.ifr_addr);
217 memset (addr, 0, sizeof (struct sockaddr_in));
218 addr->sin_family = AF_INET;
219 addr->sin_addr.s_addr = inet_addr (address);
224 if (1 != inet_pton (AF_INET, address, &addr->sin_addr.s_addr))
226 fprintf (stderr, "Failed to parse address `%s': %s\n", address,
232 if (-1 == (fd = socket (PF_INET, SOCK_DGRAM, 0)))
234 fprintf (stderr, "Error creating socket: %s\n", strerror (errno));
238 strncpy (ifr.ifr_name, dev, IFNAMSIZ);
243 if (-1 == ioctl (fd, SIOCSIFADDR, &ifr))
245 fprintf (stderr, "ioctl failed at %d: %s\n", __LINE__, strerror (errno));
252 addr = (struct sockaddr_in *) &(ifr.ifr_netmask);
253 if (1 != inet_pton (AF_INET, mask, &addr->sin_addr.s_addr))
255 fprintf (stderr, "Failed to parse address `%s': %s\n", mask,
263 if (-1 == ioctl (fd, SIOCSIFNETMASK, &ifr))
265 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
273 if (-1 == ioctl (fd, SIOCGIFFLAGS, &ifr))
275 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
281 * Add the UP and RUNNING flags
283 ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
284 if (-1 == ioctl (fd, SIOCSIFFLAGS, &ifr))
286 fprintf (stderr, "ioctl failed at line %d: %s\n", __LINE__,
293 fprintf (stderr, "close failed: %s\n", strerror (errno));
303 * The buffer filled by reading from fd_tun
305 unsigned char buftun[MAX_SIZE];
306 ssize_t buftun_size = 0;
307 unsigned char *buftun_read;
310 * The buffer filled by reading from stdin
312 unsigned char bufin[MAX_SIZE];
313 ssize_t bufin_size = 0;
314 size_t bufin_rpos = 0;
315 unsigned char *bufin_read = NULL;
320 /* read refers to reading from fd_tun, writing to stdout */
323 /* write refers to reading from stdin, writing to fd_tun */
326 while ((1 == read_open) || (1 == write_open))
332 * We are supposed to read and the buffer is empty
333 * -> select on read from tun
335 if (read_open && (0 == buftun_size))
336 FD_SET (fd_tun, &fds_r);
339 * We are supposed to read and the buffer is not empty
340 * -> select on write to stdout
342 if (read_open && (0 != buftun_size))
346 * We are supposed to write and the buffer is empty
347 * -> select on read from stdin
349 if (write_open && (NULL == bufin_read))
353 * We are supposed to write and the buffer is not empty
354 * -> select on write to tun
356 if (write_open && (NULL != bufin_read))
357 FD_SET (fd_tun, &fds_w);
359 int r = select (fd_tun + 1, &fds_r, &fds_w, NULL, NULL);
365 fprintf (stderr, "select failed: %s\n", strerror (errno));
371 if (FD_ISSET (fd_tun, &fds_r))
374 read (fd_tun, buftun + sizeof (struct GNUNET_MessageHeader),
375 MAX_SIZE - sizeof (struct GNUNET_MessageHeader));
376 if (-1 == buftun_size)
378 fprintf (stderr, "read-error: %s\n", strerror (errno));
379 shutdown (fd_tun, SHUT_RD);
380 shutdown (1, SHUT_WR);
384 else if (0 == buftun_size)
386 fprintf (stderr, "EOF on tun\n");
387 shutdown (fd_tun, SHUT_RD);
388 shutdown (1, SHUT_WR);
394 buftun_read = buftun;
395 struct GNUNET_MessageHeader *hdr =
396 (struct GNUNET_MessageHeader *) buftun;
397 buftun_size += sizeof (struct GNUNET_MessageHeader);
398 hdr->type = htons (GNUNET_MESSAGE_TYPE_VPN_HELPER);
399 hdr->size = htons (buftun_size);
402 else if (FD_ISSET (1, &fds_w))
404 ssize_t written = write (1, buftun_read, buftun_size);
408 fprintf (stderr, "write-error to stdout: %s\n", strerror (errno));
409 shutdown (fd_tun, SHUT_RD);
410 shutdown (1, SHUT_WR);
414 else if (0 == written)
416 fprintf (stderr, "write returned 0!?\n");
421 buftun_size -= written;
422 buftun_read += written;
426 if (FD_ISSET (0, &fds_r))
428 bufin_size = read (0, bufin + bufin_rpos, MAX_SIZE - bufin_rpos);
429 if (-1 == bufin_size)
431 fprintf (stderr, "read-error: %s\n", strerror (errno));
432 shutdown (0, SHUT_RD);
433 shutdown (fd_tun, SHUT_WR);
437 else if (0 == bufin_size)
439 fprintf (stderr, "EOF on stdin\n");
440 shutdown (0, SHUT_RD);
441 shutdown (fd_tun, SHUT_WR);
447 struct GNUNET_MessageHeader *hdr;
450 bufin_rpos += bufin_size;
451 if (bufin_rpos < sizeof (struct GNUNET_MessageHeader))
453 hdr = (struct GNUNET_MessageHeader *) bufin;
454 if (ntohs (hdr->type) != GNUNET_MESSAGE_TYPE_VPN_HELPER)
456 fprintf (stderr, "protocol violation!\n");
459 if (ntohs (hdr->size) > bufin_rpos)
461 bufin_read = bufin + sizeof (struct GNUNET_MessageHeader);
462 bufin_size = ntohs (hdr->size) - sizeof (struct GNUNET_MessageHeader);
463 bufin_rpos -= bufin_size + sizeof (struct GNUNET_MessageHeader);
466 else if (FD_ISSET (fd_tun, &fds_w))
468 ssize_t written = write (fd_tun, bufin_read, bufin_size);
472 fprintf (stderr, "write-error to tun: %s\n", strerror (errno));
473 shutdown (0, SHUT_RD);
474 shutdown (fd_tun, SHUT_WR);
478 else if (0 == written)
480 fprintf (stderr, "write returned 0!?\n");
485 bufin_size -= written;
486 bufin_read += written;
489 memmove (bufin, bufin_read, bufin_rpos);
490 bufin_read = NULL; /* start reading again */
502 main (int argc, char **argv)
509 fprintf (stderr, "Fatal: must supply 5 arguments!\n");
513 strncpy (dev, argv[1], IFNAMSIZ);
514 dev[IFNAMSIZ - 1] = '\0';
516 if (-1 == (fd_tun = init_tun (dev)))
518 fprintf (stderr, "Fatal: could not initialize tun-interface\n");
523 const char *address = argv[2];
524 long prefix_len = atol (argv[3]);
526 if ((prefix_len < 1) || (prefix_len > 127))
528 fprintf (stderr, "Fatal: prefix_len out of range\n");
532 set_address6 (dev, address, prefix_len);
536 const char *address = argv[4];
537 const char *mask = argv[5];
539 set_address4 (dev, address, mask);
542 uid_t uid = getuid ();
544 if (0 != setresuid (uid, uid, uid))
545 fprintf (stderr, "Failed to setresuid: %s\n", strerror (errno));
546 if (SIG_ERR == signal (SIGPIPE, SIG_IGN))
547 fprintf (stderr, "Failed to protect against SIGPIPE: %s\n",