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-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 struct in6_ifreq {
  52     struct in6_addr ifr6_addr;
  53     __u32 ifr6_prefixlen;
  54     unsigned int ifr6_ifindex;
  55 };
  56
  57 #endif
  58
  59 int running = 1;
  60
  61 void term(int sig) {
  62         fprintf(stderr, "Got SIGTERM...\n");
  63         if (sig == SIGTERM)
  64                 running = 0;
  65 }
  66
  67 static void set_address(char* dev, char* address, unsigned long prefix_len) { /* {{{ */
  68         int fd = socket(AF_INET6, SOCK_DGRAM, 0);
  69
  70         struct ifreq ifr;
  71         struct in6_ifreq ifr6;
  72
  73         struct sockaddr_in6 sa6;
  74         memset(&sa6, 0, sizeof(struct sockaddr_in6));
  75
  76         sa6.sin6_family = AF_INET6;
  77
  78         /* FIXME */ inet_pton(AF_INET6, address, sa6.sin6_addr.s6_addr);
  79
  80         memcpy((char *) &ifr6.ifr6_addr, (char *) &sa6.sin6_addr, sizeof(struct in6_addr));
  81
  82         strncpy(ifr.ifr_name, dev, IFNAMSIZ);
  83
  84         if (ioctl(fd, SIOGIFINDEX, &ifr) < 0) {
  85                 perror("SIOGIFINDEX");
  86         }
  87
  88         ifr6.ifr6_ifindex = ifr.ifr_ifindex;
  89         ifr6.ifr6_prefixlen = prefix_len;
  90
  91         if (ioctl(fd, SIOCSIFADDR, &ifr6) < 0) {
  92                 perror("SIOCSIFADDR");
  93         }
  94
  95         /* FIXME */ ioctl(fd, SIOCGIFFLAGS, &ifr);
  96         ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
  97         /* FIXME */ ioctl(fd, SIOCSIFFLAGS, &ifr);
  98 } /* }}} */
  99
 100 void setnonblocking(int fd) {/*{{{*/
 101         int opts;
 102
 103         opts = fcntl(fd,F_GETFL);
 104         if (opts < 0) {
 105                         perror("fcntl(F_GETFL)");
 106         }
 107         opts = (opts | O_NONBLOCK);
 108         if (fcntl(fd,F_SETFL,opts) < 0) {
 109                         perror("fcntl(F_SETFL)");
 110         }
 111         return;
 112 }/*}}}*/
 113
 114 int main(int argc, char** argv) {
 115         unsigned char buf[65600]; // 64k + 64;
 116
 117         char dev[IFNAMSIZ];
 118         memset(dev, 0, IFNAMSIZ);
 119
 120         signal(SIGTERM, &term);
 121
 122         int fd_tun = init_tun(dev);
 123         fprintf(stderr, "Initialized the interface %s as %d.\n", dev, fd_tun);
 124
 125         // TODO: get this out of argv
 126         char address[] = "1234::1";
 127         unsigned long prefix_len = 16;
 128
 129         set_address(dev, address, prefix_len);
 130
 131         uid_t uid = getuid ();
 132         if (setresuid (uid, uid, uid) != 0 )
 133                 fprintf (stderr, "Failed to setresuid: %m\n");
 134
 135         setnonblocking(0);
 136         setnonblocking(1);
 137         setnonblocking(fd_tun);
 138
 139         fd_set fds_w;
 140         fd_set fds_r;
 141
 142         int rea = 1;
 143         int wri = 1;
 144
 145         int write_fd_possible = 0;
 146         int write_stdout_possible = 0;
 147 outer:
 148         while((rea == 1 || wri == 1) && running == 1) {
 149                 FD_ZERO(&fds_w);
 150                 FD_ZERO(&fds_r);
 151
 152                 if (rea) {
 153                         FD_SET(fd_tun, &fds_r);
 154                         if (!write_stdout_possible)
 155                                 FD_SET(1, &fds_w);
 156                 }
 157
 158                 if (wri) {
 159                         FD_SET(0, &fds_r);
 160                         if (!write_fd_possible)
 161                                 FD_SET(fd_tun, &fds_w);
 162                 }
 163
 164                 int r = select(fd_tun+1, &fds_r, &fds_w, (fd_set*)0, 0);
 165
 166                 if(r > 0) {
 167                         if (FD_ISSET(fd_tun, &fds_w)) write_fd_possible = 1;
 168                         if (FD_ISSET(1, &fds_w)) write_stdout_possible = 1;
 169
 170                         if (FD_ISSET(0, &fds_r) && write_fd_possible) {
 171                                 write_fd_possible = 0;
 172                                 struct suid_packet *pkt = (struct suid_packet*) buf;
 173                                 r = read(0, buf, sizeof(struct GNUNET_MessageHeader));
 174                                 if (r <= 0) {
 175                                         fprintf(stderr, "read-error: %m\n");
 176                                         shutdown(fd_tun, SHUT_WR);
 177                                         shutdown(0, SHUT_RD);
 178                                         wri=0;
 179                                         goto outer;
 180                                 }
 181                                 while (r < ntohs(pkt->hdr.size)) {
 182                                         int t = read(0, buf + r, ntohs(pkt->hdr.size) - r);
 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                                         r += t;
 191                                 }
 192                                 r = 0;
 193                                 while (r < ntohs(pkt->hdr.size) - sizeof(struct GNUNET_MessageHeader)) {
 194                                         int t = write(fd_tun, pkt->data, ntohs(pkt->hdr.size) - sizeof(struct GNUNET_MessageHeader) - r);
 195                                         if (t < 0) {
 196                                                 fprintf(stderr, "write-error 3: %m\n");
 197                                                 shutdown(fd_tun, SHUT_WR);
 198                                                 shutdown(0, SHUT_RD);
 199                                                 wri = 0;
 200                                                 goto outer;
 201                                         }
 202                                         r += t;
 203                                 }
 204                         } else if (write_stdout_possible && FD_ISSET(fd_tun, &fds_r)) {
 205                                 write_stdout_possible = 0;
 206                                 r = read(fd_tun, buf, 65600);
 207                                 if (r <= 0) {
 208                                         fprintf(stderr, "read-error: %m\n");
 209                                         shutdown(fd_tun, SHUT_RD);
 210                                         shutdown(1, SHUT_WR);
 211                                         rea = 0;
 212                                         goto outer;
 213                                 }
 214                                 struct GNUNET_MessageHeader hdr = { .size = htons(r + sizeof(struct GNUNET_MessageHeader)), .type = htons(GNUNET_MESSAGE_TYPE_VPN_HELPER) };
 215                                 r = 0;
 216                                 while(r < sizeof(struct GNUNET_MessageHeader)) {
 217                                         int t = write(1, &hdr, sizeof(struct GNUNET_MessageHeader) - r);
 218                                         if (t < 0) {
 219                                                 fprintf(stderr, "write-error 2: %m\n");
 220                                                 shutdown(fd_tun, SHUT_RD);
 221                                                 shutdown(1, SHUT_WR);
 222                                                 rea = 0;
 223                                                 goto outer;
 224                                         }
 225                                         r += t;
 226                                 }
 227                                 while(r < ntohs(hdr.size)) {
 228                                         int t = write(1, buf, ntohs(hdr.size) - r);
 229                                         if (t < 0) {
 230                                                 fprintf(stderr, "write-error 1: %m, written %d/%d\n", r, ntohs(hdr.size));
 231                                                 shutdown(fd_tun, SHUT_RD);
 232                                                 shutdown(1, SHUT_WR);
 233                                                 rea = 0;
 234                                                 goto outer;
 235                                         }
 236                                         r += t;
 237                                 }
 238                         }
 239                 }
 240         }
 241         fprintf(stderr, "Quitting!\n");
 242
 243         return 0;
 244 }