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 #include <platform.h>
  27
  28 #include "gnunet-vpn-tun.h"
  29 #include "gnunet_common.h"
  30 #include "gnunet_protocols.h"
  31 #include "gnunet-vpn-helper-p.h"
  32
  33 #ifndef _LINUX_IN6_H
  34 // This is in linux/include/net/ipv6.h.
  35
  36 #define MAX_SIZE (65535 - sizeof(struct GNUNET_MessageHeader))
  37
  38 struct in6_ifreq {
  39     struct in6_addr ifr6_addr;
  40     uint32_t ifr6_prefixlen;
  41     unsigned int ifr6_ifindex;
  42 };
  43
  44 #endif
  45
  46 int running = 1;
  47
  48 void term(int sig) {
  49         fprintf(stderr, "Got SIGTERM...\n");
  50         if (sig == SIGTERM)
  51                 running = 0;
  52 }
  53
  54 static void set_address6(char* dev, char* address, unsigned long prefix_len) { /* {{{ */
  55         int fd = socket(AF_INET6, SOCK_DGRAM, 0);
  56
  57         struct ifreq ifr;
  58         struct in6_ifreq ifr6;
  59
  60         struct sockaddr_in6 sa6;
  61         memset(&sa6, 0, sizeof(struct sockaddr_in6));
  62
  63         sa6.sin6_family = AF_INET6;
  64
  65         /* FIXME */ inet_pton(AF_INET6, address, sa6.sin6_addr.s6_addr);
  66
  67         memcpy((char *) &ifr6.ifr6_addr, (char *) &sa6.sin6_addr, sizeof(struct in6_addr));
  68
  69         strncpy(ifr.ifr_name, dev, IFNAMSIZ);
  70
  71         if (ioctl(fd, SIOGIFINDEX, &ifr) < 0) {
  72                 perror("SIOGIFINDEX");
  73         }
  74
  75         ifr6.ifr6_ifindex = ifr.ifr_ifindex;
  76         ifr6.ifr6_prefixlen = prefix_len;
  77
  78         if (ioctl(fd, SIOCSIFADDR, &ifr6) < 0) {
  79                 perror("SIOCSIFADDR");
  80         }
  81
  82         /* FIXME */ ioctl(fd, SIOCGIFFLAGS, &ifr);
  83         ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
  84         /* FIXME */ ioctl(fd, SIOCSIFFLAGS, &ifr);
  85         close(fd);
  86 } /* }}} */
  87
  88 static void set_address4(char* dev, char* address, char* mask) { /* {{{ */
  89         int fd=0;
  90         struct sockaddr_in* addr;
  91         struct ifreq ifr;
  92
  93         memset(&ifr, 0, sizeof(struct ifreq));
  94         addr = (struct sockaddr_in *)&(ifr.ifr_addr);
  95         memset(addr, 0, sizeof(struct sockaddr_in));
  96         addr->sin_family = AF_INET;
  97         addr->sin_addr.s_addr = inet_addr(address);
  98
  99         /* FIXME */ inet_pton(AF_INET, address, &addr->sin_addr.s_addr);
 100
 101         fd = socket(PF_INET, SOCK_DGRAM, 0);
 102         if(fd < 0) {
 103                 perror("socket()");
 104                 return;
 105         }
 106
 107         strncpy(ifr.ifr_name, dev, IFNAMSIZ);
 108
 109         if(ioctl(fd, SIOCSIFADDR, &ifr) != 0 ) {
 110                 perror("SIOCSIFADDR");
 111                 close(fd);
 112                 return;
 113         }
 114
 115         addr = (struct sockaddr_in*)&(ifr.ifr_netmask);
 116         /* FIXME */ inet_pton(AF_INET, mask, &addr->sin_addr.s_addr);
 117
 118         if(ioctl(fd, SIOCSIFNETMASK, &ifr) != 0 ) {
 119                 perror("SIOCSIFNETMASK");
 120                 close(fd);
 121                 return;
 122         }
 123
 124         /* FIXME */ ioctl(fd, SIOCGIFFLAGS, &ifr);
 125         ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
 126         /* FIXME */ ioctl(fd, SIOCSIFFLAGS, &ifr);
 127         close(fd);
 128 } /* }}} */
 129
 130 void setnonblocking(int fd) {/*{{{*/
 131         int opts;
 132
 133         opts = fcntl(fd,F_GETFL);
 134         if (opts < 0) {
 135                         perror("fcntl(F_GETFL)");
 136         }
 137         opts = (opts | O_NONBLOCK);
 138         if (fcntl(fd,F_SETFL,opts) < 0) {
 139                         perror("fcntl(F_SETFL)");
 140         }
 141         return;
 142 }/*}}}*/
 143
 144 int main(int argc, char** argv) {
 145         unsigned char buf[MAX_SIZE];
 146
 147         char dev[IFNAMSIZ];
 148         memset(dev, 0, IFNAMSIZ);
 149
 150         signal(SIGTERM, &term);
 151
 152         int fd_tun = init_tun(dev);
 153
 154         if (fd_tun < 0) {
 155                 fprintf(stderr, "Could not initialize tun-interface: %s\n", strerror(errno));
 156                 exit(1);
 157         }
 158
 159         {
 160         // TODO: get this out of argv
 161         char address[] = "1234::1";
 162         unsigned long prefix_len = 16;
 163
 164         set_address6(dev, address, prefix_len);
 165         }
 166
 167         {
 168         char address[] = "10.10.10.1";
 169         char mask[] = "255.255.255.252";
 170
 171         set_address4(dev, address, mask);
 172         }
 173
 174         uid_t uid = getuid ();
 175         if (setresuid (uid, uid, uid) != 0 )
 176                 fprintf (stderr, "Failed to setresuid: %s\n", strerror(errno));
 177
 178         setnonblocking(0);
 179         setnonblocking(1);
 180         setnonblocking(fd_tun);
 181
 182         fd_set fds_w;
 183         fd_set fds_r;
 184
 185         int rea = 1;
 186         int wri = 1;
 187
 188         int write_fd_possible = 0;
 189         int write_stdout_possible = 0;
 190 outer:
 191         while((rea == 1 || wri == 1) && running == 1) {
 192                 FD_ZERO(&fds_w);
 193                 FD_ZERO(&fds_r);
 194
 195                 if (rea) {
 196                         FD_SET(fd_tun, &fds_r);
 197                         if (!write_stdout_possible)
 198                                 FD_SET(1, &fds_w);
 199                 }
 200
 201                 if (wri) {
 202                         FD_SET(0, &fds_r);
 203                         if (!write_fd_possible)
 204                                 FD_SET(fd_tun, &fds_w);
 205                 }
 206
 207                 int r = select(fd_tun+1, &fds_r, &fds_w, (fd_set*)0, 0);
 208
 209                 if(r > 0) {
 210                         if (FD_ISSET(fd_tun, &fds_w)) write_fd_possible = 1;
 211                         if (FD_ISSET(1, &fds_w)) write_stdout_possible = 1;
 212
 213                         if (FD_ISSET(0, &fds_r) && write_fd_possible) {
 214                                 write_fd_possible = 0;
 215                                 struct suid_packet *pkt = (struct suid_packet*) buf;
 216                                 r = read(0, buf, sizeof(struct GNUNET_MessageHeader));
 217                                 if (r <= 0) {
 218                                         fprintf(stderr, "read-error: %m\n");
 219                                         shutdown(fd_tun, SHUT_WR);
 220                                         shutdown(0, SHUT_RD);
 221                                         wri=0;
 222                                         goto outer;
 223                                 }
 224                                 if(pkt->hdr.type != ntohs(GNUNET_MESSAGE_TYPE_VPN_HELPER)) abort();
 225                                 while (r < ntohs(pkt->hdr.size)) {
 226                                         int t = read(0, buf + r, ntohs(pkt->hdr.size) - r);
 227                                         if (r < 0) {
 228                                                 fprintf(stderr, "read-error: %m\n");
 229                                                 shutdown(fd_tun, SHUT_WR);
 230                                                 shutdown(0, SHUT_RD);
 231                                                 wri=0;
 232                                                 goto outer;
 233                                         }
 234                                         r += t;
 235                                 }
 236                                 r = 0;
 237                                 while (r < ntohs(pkt->hdr.size) - sizeof(struct GNUNET_MessageHeader)) {
 238                                         int t = write(fd_tun, pkt->data, ntohs(pkt->hdr.size) - sizeof(struct GNUNET_MessageHeader) - r);
 239                                         if (t < 0) {
 240                                                 fprintf(stderr, "write-error 3: %m\n");
 241                                                 shutdown(fd_tun, SHUT_WR);
 242                                                 shutdown(0, SHUT_RD);
 243                                                 wri = 0;
 244                                                 goto outer;
 245                                         }
 246                                         r += t;
 247                                 }
 248                         } else if (write_stdout_possible && FD_ISSET(fd_tun, &fds_r)) {
 249                                 write_stdout_possible = 0;
 250                                 r = read(fd_tun, buf, MAX_SIZE);
 251                                 if (r <= 0) {
 252                                         fprintf(stderr, "read-error: %m\n");
 253                                         shutdown(fd_tun, SHUT_RD);
 254                                         shutdown(1, SHUT_WR);
 255                                         rea = 0;
 256                                         goto outer;
 257                                 }
 258                                 struct GNUNET_MessageHeader hdr = { .size = htons(r + sizeof(struct GNUNET_MessageHeader)), .type = htons(GNUNET_MESSAGE_TYPE_VPN_HELPER) };
 259                                 r = 0;
 260                                 while(r < sizeof(struct GNUNET_MessageHeader)) {
 261                                         int t = write(1, &hdr, sizeof(struct GNUNET_MessageHeader) - r);
 262                                         if (t < 0) {
 263                                                 fprintf(stderr, "write-error 2: %m\n");
 264                                                 shutdown(fd_tun, SHUT_RD);
 265                                                 shutdown(1, SHUT_WR);
 266                                                 rea = 0;
 267                                                 goto outer;
 268                                         }
 269                                         r += t;
 270                                 }
 271                                 while(r < ntohs(hdr.size)) {
 272                                         int t = write(1, buf, ntohs(hdr.size) - r);
 273                                         if (t < 0) {
 274                                                 fprintf(stderr, "write-error 1: %s, written %d/%d\n", strerror(errno), r, ntohs(hdr.size));
 275                                                 shutdown(fd_tun, SHUT_RD);
 276                                                 shutdown(1, SHUT_WR);
 277                                                 rea = 0;
 278                                                 goto outer;
 279                                         }
 280                                         r += t;
 281                                 }
 282                         }
 283                 }
 284         }
 285
 286         close(fd_tun);
 287
 288         return 0;
 289 }