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