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)))
85 "Error opening `%s': %s\n", "/dev/net/tun", strerror (errno));
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))
104 "Error with ioctl on `%s': %s\n",
105 "/dev/net/tun", strerror (errno));
109 strcpy (dev, ifr.ifr_name);
115 * @brief Sets the IPv6-Address given in address on the interface dev
117 * @param dev the interface to configure
118 * @param address the IPv6-Address
119 * @param prefix_len the length of the network-prefix
122 set_address6 (const char *dev,
124 unsigned long prefix_len)
127 struct in6_ifreq ifr6;
128 struct sockaddr_in6 sa6;
132 * parse the new address
134 memset (&sa6, 0, sizeof (struct sockaddr_in6));
135 if (1 != inet_pton (AF_INET6, address, sa6.sin6_addr.s6_addr))
138 "Failed to parse address `%s': %s\n",
139 address, strerror (errno));
143 if (-1 == (fd = socket (PF_INET6, SOCK_DGRAM, 0)))
146 "Error creating socket: %s\n",
151 sa6.sin6_family = AF_INET6;
152 memcpy (&ifr6.ifr6_addr,
154 sizeof (struct in6_addr));
158 * Get the index of the if
160 strncpy (ifr.ifr_name, dev, IFNAMSIZ);
161 if (-1 == ioctl (fd, SIOGIFINDEX, &ifr))
164 "ioctl failed at %d: %s\n",
169 ifr6.ifr6_ifindex = ifr.ifr_ifindex;
171 ifr6.ifr6_prefixlen = prefix_len;
176 if (-1 == ioctl (fd, SIOCSIFADDR, &ifr6))
179 "ioctl failed at line %d: %s\n", __LINE__, strerror (errno));
186 if (-1 == ioctl (fd, SIOCGIFFLAGS, &ifr))
189 "ioctl failed at line %d: %s\n", __LINE__, strerror (errno));
194 * Add the UP and RUNNING flags
196 ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
197 if (-1 == ioctl (fd, SIOCSIFFLAGS, &ifr))
200 "ioctl failed at line %d: %s\n", __LINE__, strerror (errno));
206 fprintf (stderr, "close failed: %s\n", strerror (errno));
213 * @brief Sets the IPv4-Address given in address on the interface dev
215 * @param dev the interface to configure
216 * @param address the IPv4-Address
217 * @param mask the netmask
220 set_address4 (const char *dev,
225 struct sockaddr_in *addr;
228 memset (&ifr, 0, sizeof (struct ifreq));
229 addr = (struct sockaddr_in *) &(ifr.ifr_addr);
230 memset (addr, 0, sizeof (struct sockaddr_in));
231 addr->sin_family = AF_INET;
232 addr->sin_addr.s_addr = inet_addr (address);
237 if (1 != inet_pton (AF_INET, address, &addr->sin_addr.s_addr))
240 "Failed to parse address `%s': %s\n",
241 address, strerror (errno));
246 if (-1 == (fd = socket (PF_INET, SOCK_DGRAM, 0)))
249 "Error creating socket: %s\n",
254 strncpy (ifr.ifr_name, dev, IFNAMSIZ);
259 if (-1 == ioctl (fd, SIOCSIFADDR, &ifr))
262 "ioctl failed at %d: %s\n",
271 addr = (struct sockaddr_in *) &(ifr.ifr_netmask);
272 if (1 != inet_pton (AF_INET, mask, &addr->sin_addr.s_addr))
275 "Failed to parse address `%s': %s\n",
284 if (-1 == ioctl (fd, SIOCSIFNETMASK, &ifr))
287 "ioctl failed at line %d: %s\n", __LINE__, strerror (errno));
294 if (-1 == ioctl (fd, SIOCGIFFLAGS, &ifr))
297 "ioctl failed at line %d: %s\n", __LINE__, strerror (errno));
302 * Add the UP and RUNNING flags
304 ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
305 if (-1 == ioctl (fd, SIOCSIFFLAGS, &ifr))
308 "ioctl failed at line %d: %s\n", __LINE__, strerror (errno));
314 fprintf (stderr, "close failed: %s\n", strerror (errno));
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;
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 */
343 /* write refers to reading from stdin, writing to fd_tun */
346 while ((1 == read_open) || (1 == write_open))
352 * We are supposed to read and the buffer is empty
353 * -> select on read from tun
355 if (read_open && (0 == buftun_size))
356 FD_SET (fd_tun, &fds_r);
359 * We are supposed to read and the buffer is not empty
360 * -> select on write to stdout
362 if (read_open && (0 != buftun_size))
366 * We are supposed to write and the buffer is empty
367 * -> select on read from stdin
369 if (write_open && (NULL == bufin_read))
373 * We are supposed to write and the buffer is not empty
374 * -> select on write to tun
376 if (write_open && (NULL != bufin_read))
377 FD_SET (fd_tun, &fds_w);
379 int r = select (fd_tun + 1, &fds_r, &fds_w, NULL, NULL);
384 fprintf (stderr, "select failed: %s\n", strerror (errno));
390 if (FD_ISSET (fd_tun, &fds_r))
393 read (fd_tun, buftun + sizeof (struct GNUNET_MessageHeader),
394 MAX_SIZE - sizeof (struct GNUNET_MessageHeader));
395 if (-1 == buftun_size)
397 fprintf (stderr, "read-error: %s\n", strerror (errno));
398 shutdown (fd_tun, SHUT_RD);
399 shutdown (1, SHUT_WR);
403 else if (0 == buftun_size)
405 fprintf (stderr, "EOF on tun\n");
406 shutdown (fd_tun, SHUT_RD);
407 shutdown (1, SHUT_WR);
413 buftun_read = buftun;
414 struct GNUNET_MessageHeader *hdr =
415 (struct GNUNET_MessageHeader *) buftun;
416 buftun_size += sizeof (struct GNUNET_MessageHeader);
417 hdr->type = htons (GNUNET_MESSAGE_TYPE_VPN_HELPER);
418 hdr->size = htons (buftun_size);
421 else if (FD_ISSET (1, &fds_w))
423 ssize_t written = write (1, buftun_read, buftun_size);
427 "write-error to stdout: %s\n",
429 shutdown (fd_tun, SHUT_RD);
430 shutdown (1, SHUT_WR);
434 else if (0 == written)
437 "write returned 0!?\n");
442 buftun_size -= written;
443 buftun_read += written;
447 if (FD_ISSET (0, &fds_r))
449 bufin_size = read (0, bufin + bufin_rpos, MAX_SIZE - bufin_rpos);
450 if (-1 == bufin_size)
455 shutdown (0, SHUT_RD);
456 shutdown (fd_tun, SHUT_WR);
460 else if (0 == bufin_size)
464 shutdown (0, SHUT_RD);
465 shutdown (fd_tun, SHUT_WR);
471 struct GNUNET_MessageHeader *hdr;
474 bufin_rpos += bufin_size;
475 if (bufin_rpos < sizeof (struct GNUNET_MessageHeader))
477 hdr = (struct GNUNET_MessageHeader *) bufin;
478 if (ntohs (hdr->type) != GNUNET_MESSAGE_TYPE_VPN_HELPER)
480 fprintf (stderr, "protocol violation!\n");
483 if (ntohs (hdr->size) > bufin_rpos)
485 bufin_read = bufin + sizeof (struct GNUNET_MessageHeader);
486 bufin_size = ntohs (hdr->size) - sizeof (struct GNUNET_MessageHeader);
487 bufin_rpos -= bufin_size + sizeof (struct GNUNET_MessageHeader);
490 else if (FD_ISSET (fd_tun, &fds_w))
492 ssize_t written = write (fd_tun, bufin_read, bufin_size);
495 fprintf (stderr, "write-error to tun: %s\n",
497 shutdown (0, SHUT_RD);
498 shutdown (fd_tun, SHUT_WR);
502 else if (0 == written)
505 "write returned 0!?\n");
510 bufin_size -= written;
511 bufin_read += written;
517 bufin_read = NULL; /* start reading again */
529 main (int argc, char **argv)
537 "Fatal: must supply 5 arguments!\n");
541 strncpy(dev, argv[1], IFNAMSIZ);
542 dev[IFNAMSIZ - 1] = '\0';
544 if (-1 == (fd_tun = init_tun (dev)))
547 "Fatal: could not initialize tun-interface\n");
552 const char *address = argv[2];
553 long prefix_len = atol(argv[3]);
555 if ( (prefix_len < 1) || (prefix_len > 127) )
557 fprintf(stderr, "Fatal: prefix_len out of range\n");
561 set_address6 (dev, address, prefix_len);
565 const char *address = argv[4];
566 const char *mask = argv[5];
568 set_address4 (dev, address, mask);
571 uid_t uid = getuid ();
572 if (0 != setresuid (uid, uid, uid))
574 "Failed to setresuid: %s\n",
576 if (SIG_ERR == signal (SIGPIPE, SIG_IGN))
578 "Failed to protect against SIGPIPE: %s\n",