src/vpn/gnunet-vpn-helper.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-helper-p.h"
  44 #include "gnunet-vpn-tun.h"
  45
  46 #ifndef _LINUX_IN6_H
  47 // This is in linux/include/net/ipv6.h.
  48
  49 struct in6_ifreq {
  50     struct in6_addr ifr6_addr;
  51     __u32 ifr6_prefixlen;
  52     unsigned int ifr6_ifindex;
  53 };
  54
  55 #endif
  56
  57 int running = 1;
  58
  59 void term(int sig) {
  60         fprintf(stderr, "Got SIGTERM...\n");
  61         if (sig == SIGTERM)
  62                 running = 0;
  63 }
  64
  65 static void set_address(char* dev, char* address, unsigned long prefix_len) { /* {{{ */
  66         int fd = socket(AF_INET6, SOCK_DGRAM, 0);
  67
  68         struct ifreq ifr;
  69         struct in6_ifreq ifr6;
  70
  71         struct sockaddr_in6 sa6;
  72         memset(&sa6, 0, sizeof(struct sockaddr_in6));
  73
  74         sa6.sin6_family = AF_INET6;
  75
  76         /* FIXME */ inet_pton(AF_INET6, address, sa6.sin6_addr.s6_addr);
  77
  78         memcpy((char *) &ifr6.ifr6_addr, (char *) &sa6.sin6_addr, sizeof(struct in6_addr));
  79
  80         strncpy(ifr.ifr_name, dev, IFNAMSIZ);
  81
  82         if (ioctl(fd, SIOGIFINDEX, &ifr) < 0) {
  83                 perror("SIOGIFINDEX");
  84         }
  85
  86         ifr6.ifr6_ifindex = ifr.ifr_ifindex;
  87         ifr6.ifr6_prefixlen = prefix_len;
  88
  89         if (ioctl(fd, SIOCSIFADDR, &ifr6) < 0) {
  90                 perror("SIOCSIFADDR");
  91         }
  92
  93         /* FIXME */ ioctl(fd, SIOCGIFFLAGS, &ifr);
  94         ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
  95         /* FIXME */ ioctl(fd, SIOCSIFFLAGS, &ifr);
  96 } /* }}} */
  97
  98 void setnonblocking(int fd) {/*{{{*/
  99         int opts;
 100
 101         opts = fcntl(fd,F_GETFL);
 102         if (opts < 0) {
 103                         perror("fcntl(F_GETFL)");
 104         }
 105         opts = (opts | O_NONBLOCK);
 106         if (fcntl(fd,F_SETFL,opts) < 0) {
 107                         perror("fcntl(F_SETFL)");
 108         }
 109         return;
 110 }/*}}}*/
 111
 112 int main(int argc, char** argv) {
 113         unsigned char buf[65600]; // 64k + 64;
 114
 115         char dev[IFNAMSIZ];
 116         memset(dev, 0, IFNAMSIZ);
 117
 118         signal(SIGTERM, &term);
 119
 120         int fd_tun = init_tun(dev);
 121         fprintf(stderr, "Initialized the interface %s as %d.\n", dev, fd_tun);
 122
 123         // TODO: get this out of argv
 124         char address[] = "1234::1";
 125         unsigned long prefix_len = 16;
 126
 127         set_address(dev, address, prefix_len);
 128
 129         uid_t uid = getuid ();
 130         if (setresuid (uid, uid, uid) != 0 )
 131                 fprintf (stderr, "Failed to setresuid: %m\n");
 132
 133         setnonblocking(0);
 134         setnonblocking(1);
 135         setnonblocking(fd_tun);
 136
 137         fd_set fds_w;
 138         fd_set fds_r;
 139
 140         int rea = 1;
 141         int wri = 1;
 142
 143         int write_fd_possible = 0;
 144         int write_stdout_possible = 0;
 145 outer:
 146         while((rea == 1 || wri == 1) && running == 1) {
 147                 FD_ZERO(&fds_w);
 148                 FD_ZERO(&fds_r);
 149
 150                 if (rea) {
 151                         FD_SET(fd_tun, &fds_r);
 152                         if (!write_stdout_possible)
 153                                 FD_SET(1, &fds_w);
 154                 }
 155
 156                 if (wri) {
 157                         FD_SET(0, &fds_r);
 158                         if (!write_fd_possible)
 159                                 FD_SET(fd_tun, &fds_w);
 160                 }
 161
 162                 int r = select(fd_tun+1, &fds_r, &fds_w, (fd_set*)0, 0);
 163
 164                 if(r > 0) {
 165                         if (FD_ISSET(fd_tun, &fds_w)) write_fd_possible = 1;
 166                         if (FD_ISSET(1, &fds_w)) write_stdout_possible = 1;
 167
 168                         if (FD_ISSET(0, &fds_r) && write_fd_possible) {
 169                                 write_fd_possible = 0;
 170                                 struct suid_packet *pkt = (struct suid_packet*) buf;
 171                                 r = read(0, buf, sizeof(struct suid_packet_header));
 172                                 if (r <= 0) {
 173                                         fprintf(stderr, "read-error: %m\n");
 174                                         shutdown(fd_tun, SHUT_WR);
 175                                         shutdown(0, SHUT_RD);
 176                                         wri=0;
 177                                         goto outer;
 178                                 }
 179                                 while (r < ntohl(pkt->hdr.size)) {
 180                                         int t = read(0, buf + r, ntohl(pkt->hdr.size) - r);
 181                                         if (r < 0) {
 182                                                 fprintf(stderr, "read-error: %m\n");
 183                                                 shutdown(fd_tun, SHUT_WR);
 184                                                 shutdown(0, SHUT_RD);
 185                                                 wri=0;
 186                                                 goto outer;
 187                                         }
 188                                         r += t;
 189                                 }
 190                                 r = 0;
 191                                 while (r < ntohl(pkt->hdr.size) - sizeof(struct suid_packet_header)) {
 192                                         int t = write(fd_tun, pkt->data, ntohl(pkt->hdr.size) - sizeof(struct suid_packet_header) - r);
 193                                         if (t < 0) {
 194                                                 fprintf(stderr, "write-error 3: %m\n");
 195                                                 shutdown(fd_tun, SHUT_WR);
 196                                                 shutdown(0, SHUT_RD);
 197                                                 wri = 0;
 198                                                 goto outer;
 199                                         }
 200                                         r += t;
 201                                 }
 202                         } else if (write_stdout_possible && FD_ISSET(fd_tun, &fds_r)) {
 203                                 write_stdout_possible = 0;
 204                                 r = read(fd_tun, buf, 65600);
 205                                 if (r <= 0) {
 206                                         fprintf(stderr, "read-error: %m\n");
 207                                         shutdown(fd_tun, SHUT_RD);
 208                                         shutdown(1, SHUT_WR);
 209                                         rea = 0;
 210                                         goto outer;
 211                                 }
 212                                 struct suid_packet_header hdr = { .size = htonl(r + sizeof(struct suid_packet_header))};
 213                                 r = 0;
 214                                 while(r < sizeof(struct suid_packet_header)) {
 215                                         int t = write(1, &hdr, sizeof(struct suid_packet_header) - r);
 216                                         if (t < 0) {
 217                                                 fprintf(stderr, "write-error 2: %m\n");
 218                                                 shutdown(fd_tun, SHUT_RD);
 219                                                 shutdown(1, SHUT_WR);
 220                                                 rea = 0;
 221                                                 goto outer;
 222                                         }
 223                                         r += t;
 224                                 }
 225                                 while(r < ntohl(hdr.size)) {
 226                                         int t = write(1, buf, ntohl(hdr.size) - r);
 227                                         if (t < 0) {
 228                                                 fprintf(stderr, "write-error 1: %m, written %d/%d\n", r, ntohl(hdr.size));
 229                                                 shutdown(fd_tun, SHUT_RD);
 230                                                 shutdown(1, SHUT_WR);
 231                                                 rea = 0;
 232                                                 goto outer;
 233                                         }
 234                                         r += t;
 235                                 }
 236                         }
 237                 }
 238         }
 239         fprintf(stderr, "Quitting!\n");
 240
 241         return 0;
 242 }