src/vpn/gnunet-helper-vpn.c

   1 /*
   2      This file is part of GNUnet.
   3      (C) 2010 Christian Grothoff
   4
   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.
   9
  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.
  14
  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.
  19 */
  20
  21 /**
  22  * @file vpn/gnunet-daemon-vpn.c
  23  * @brief
  24  * @author Philipp Tölke
  25  */
  26 #define _GNU_SOURCE
  27 #include <arpa/inet.h>
  28 #include <linux/if.h>
  29 #include <unistd.h>
  30 #include <stdlib.h>
  31 #include <fcntl.h>
  32
  33 #include <sys/types.h>
  34 #include <sys/socket.h>
  35 #include <sys/ioctl.h>
  36
  37 #include <string.h>
  38
  39 #include <signal.h>
  40
  41 #include <stdio.h>
  42 #include <unistd.h>
  43
  44 #include "gnunet-vpn-tun.h"
  45 #include "gnunet_common.h"
  46 #include "gnunet_protocols.h"
  47 #include "gnunet-vpn-helper-p.h"
  48
  49 #ifndef _LINUX_IN6_H
  50 // This is in linux/include/net/ipv6.h.
  51
  52 #define MAX_SIZE (65535 - sizeof(struct GNUNET_MessageHeader))
  53
  54 struct in6_ifreq {
  55     struct in6_addr ifr6_addr;
  56     __u32 ifr6_prefixlen;
  57     unsigned int ifr6_ifindex;
  58 };
  59
  60 #endif
  61
  62 int running = 1;
  63
  64 void term(int sig) {
  65         fprintf(stderr, "Got SIGTERM...\n");
  66         if (sig == SIGTERM)
  67                 running = 0;
  68 }
  69
  70 static void set_address(char* dev, char* address, unsigned long prefix_len) { /* {{{ */
  71         int fd = socket(AF_INET6, SOCK_DGRAM, 0);
  72
  73         struct ifreq ifr;
  74         struct in6_ifreq ifr6;
  75
  76         struct sockaddr_in6 sa6;
  77         memset(&sa6, 0, sizeof(struct sockaddr_in6));
  78
  79         sa6.sin6_family = AF_INET6;
  80
  81         /* FIXME */ inet_pton(AF_INET6, address, sa6.sin6_addr.s6_addr);
  82
  83         memcpy((char *) &ifr6.ifr6_addr, (char *) &sa6.sin6_addr, sizeof(struct in6_addr));
  84
  85         strncpy(ifr.ifr_name, dev, IFNAMSIZ);
  86
  87         if (ioctl(fd, SIOGIFINDEX, &ifr) < 0) {
  88                 perror("SIOGIFINDEX");
  89         }
  90
  91         ifr6.ifr6_ifindex = ifr.ifr_ifindex;
  92         ifr6.ifr6_prefixlen = prefix_len;
  93
  94         if (ioctl(fd, SIOCSIFADDR, &ifr6) < 0) {
  95                 perror("SIOCSIFADDR");
  96         }
  97
  98         /* FIXME */ ioctl(fd, SIOCGIFFLAGS, &ifr);
  99         ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
 100         /* FIXME */ ioctl(fd, SIOCSIFFLAGS, &ifr);
 101 } /* }}} */
 102
 103 void setnonblocking(int fd) {/*{{{*/
 104         int opts;
 105
 106         opts = fcntl(fd,F_GETFL);
 107         if (opts < 0) {
 108                         perror("fcntl(F_GETFL)");
 109         }
 110         opts = (opts | O_NONBLOCK);
 111         if (fcntl(fd,F_SETFL,opts) < 0) {
 112                         perror("fcntl(F_SETFL)");
 113         }
 114         return;
 115 }/*}}}*/
 116
 117 int main(int argc, char** argv) {
 118         unsigned char buf[MAX_SIZE];
 119
 120         char dev[IFNAMSIZ];
 121         memset(dev, 0, IFNAMSIZ);
 122
 123         signal(SIGTERM, &term);
 124
 125         int fd_tun = init_tun(dev);
 126
 127         if (fd_tun < 0) {
 128                 fprintf(stderr, "Could not initialize tun-interface: %m\n");
 129                 exit(1);
 130         }
 131
 132         fprintf(stderr, "Initialized the interface %s as %d.\n", dev, fd_tun);
 133
 134         // TODO: get this out of argv
 135         char address[] = "1234::1";
 136         unsigned long prefix_len = 16;
 137
 138         set_address(dev, address, prefix_len);
 139
 140         uid_t uid = getuid ();
 141         if (setresuid (uid, uid, uid) != 0 )
 142                 fprintf (stderr, "Failed to setresuid: %m\n");
 143
 144         setnonblocking(0);
 145         setnonblocking(1);
 146         setnonblocking(fd_tun);
 147
 148         fd_set fds_w;
 149         fd_set fds_r;
 150
 151         int rea = 1;
 152         int wri = 1;
 153
 154         int write_fd_possible = 0;
 155         int write_stdout_possible = 0;
 156 outer:
 157         while((rea == 1 || wri == 1) && running == 1) {
 158                 FD_ZERO(&fds_w);
 159                 FD_ZERO(&fds_r);
 160
 161                 if (rea) {
 162                         FD_SET(fd_tun, &fds_r);
 163                         if (!write_stdout_possible)
 164                                 FD_SET(1, &fds_w);
 165                 }
 166
 167                 if (wri) {
 168                         FD_SET(0, &fds_r);
 169                         if (!write_fd_possible)
 170                                 FD_SET(fd_tun, &fds_w);
 171                 }
 172
 173                 int r = select(fd_tun+1, &fds_r, &fds_w, (fd_set*)0, 0);
 174
 175                 if(r > 0) {
 176                         if (FD_ISSET(fd_tun, &fds_w)) write_fd_possible = 1;
 177                         if (FD_ISSET(1, &fds_w)) write_stdout_possible = 1;
 178
 179                         if (FD_ISSET(0, &fds_r) && write_fd_possible) {
 180                                 write_fd_possible = 0;
 181                                 struct suid_packet *pkt = (struct suid_packet*) buf;
 182                                 r = read(0, buf, sizeof(struct GNUNET_MessageHeader));
 183                                 if (r <= 0) {
 184                                         fprintf(stderr, "read-error: %m\n");
 185                                         shutdown(fd_tun, SHUT_WR);
 186                                         shutdown(0, SHUT_RD);
 187                                         wri=0;
 188                                         goto outer;
 189                                 }
 190                                 while (r < ntohs(pkt->hdr.size)) {
 191                                         int t = read(0, buf + r, ntohs(pkt->hdr.size) - r);
 192                                         if (r < 0) {
 193                                                 fprintf(stderr, "read-error: %m\n");
 194                                                 shutdown(fd_tun, SHUT_WR);
 195                                                 shutdown(0, SHUT_RD);
 196                                                 wri=0;
 197                                                 goto outer;
 198                                         }
 199                                         r += t;
 200                                 }
 201                                 r = 0;
 202                                 while (r < ntohs(pkt->hdr.size) - sizeof(struct GNUNET_MessageHeader)) {
 203                                         int t = write(fd_tun, pkt->data, ntohs(pkt->hdr.size) - sizeof(struct GNUNET_MessageHeader) - r);
 204                                         if (t < 0) {
 205                                                 fprintf(stderr, "write-error 3: %m\n");
 206                                                 shutdown(fd_tun, SHUT_WR);
 207                                                 shutdown(0, SHUT_RD);
 208                                                 wri = 0;
 209                                                 goto outer;
 210                                         }
 211                                         r += t;
 212                                 }
 213                         } else if (write_stdout_possible && FD_ISSET(fd_tun, &fds_r)) {
 214                                 write_stdout_possible = 0;
 215                                 r = read(fd_tun, buf, MAX_SIZE);
 216                                 if (r <= 0) {
 217                                         fprintf(stderr, "read-error: %m\n");
 218                                         shutdown(fd_tun, SHUT_RD);
 219                                         shutdown(1, SHUT_WR);
 220                                         rea = 0;
 221                                         goto outer;
 222                                 }
 223                                 struct GNUNET_MessageHeader hdr = { .size = htons(r + sizeof(struct GNUNET_MessageHeader)), .type = htons(GNUNET_MESSAGE_TYPE_VPN_HELPER) };
 224                                 r = 0;
 225                                 while(r < sizeof(struct GNUNET_MessageHeader)) {
 226                                         int t = write(1, &hdr, sizeof(struct GNUNET_MessageHeader) - r);
 227                                         if (t < 0) {
 228                                                 fprintf(stderr, "write-error 2: %m\n");
 229                                                 shutdown(fd_tun, SHUT_RD);
 230                                                 shutdown(1, SHUT_WR);
 231                                                 rea = 0;
 232                                                 goto outer;
 233                                         }
 234                                         r += t;
 235                                 }
 236                                 while(r < ntohs(hdr.size)) {
 237                                         int t = write(1, buf, ntohs(hdr.size) - r);
 238                                         if (t < 0) {
 239                                                 fprintf(stderr, "write-error 1: %m, written %d/%d\n", r, ntohs(hdr.size));
 240                                                 shutdown(fd_tun, SHUT_RD);
 241                                                 shutdown(1, SHUT_WR);
 242                                                 rea = 0;
 243                                                 goto outer;
 244                                         }
 245                                         r += t;
 246                                 }
 247                         }
 248                 }
 249         }
 250         fprintf(stderr, "Quitting!\n");
 251
 252         return 0;
 253 }