src/uml_device.c

   1 /*
   2     device.c -- UML network socket
   3     Copyright (C) 2002-2005 Ivo Timmermans,
   4                   2002-2013 Guus Sliepen <guus@tinc-vpn.org>
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License along
  17     with this program; if not, write to the Free Software Foundation, Inc.,
  18     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19 */
  20
  21 #include "system.h"
  22
  23 #include <sys/un.h>
  24
  25 #include "conf.h"
  26 #include "device.h"
  27 #include "names.h"
  28 #include "net.h"
  29 #include "logger.h"
  30 #include "utils.h"
  31 #include "route.h"
  32 #include "xalloc.h"
  33
  34 static int listen_fd = -1;
  35 static int request_fd = -1;
  36 static int data_fd = -1;
  37 static int write_fd = -1;
  38 static int state = 0;
  39 static char *device_info;
  40
  41 enum request_type { REQ_NEW_CONTROL };
  42
  43 static struct request {
  44   uint32_t magic;
  45   uint32_t version;
  46   enum request_type type;
  47   struct sockaddr_un sock;
  48 } request;
  49
  50 static struct sockaddr_un data_sun;
  51
  52 static bool setup_device(void) {
  53         struct sockaddr_un listen_sun;
  54         static const int one = 1;
  55         struct {
  56                 char zero;
  57                 int pid;
  58                 int usecs;
  59         } name;
  60         struct timeval tv;
  61
  62         if(!get_config_string(lookup_config(config_tree, "Device"), &device))
  63                 xasprintf(&device, LOCALSTATEDIR "/run/%s.umlsocket", identname);
  64
  65         get_config_string(lookup_config(config_tree, "Interface"), &iface);
  66
  67         device_info = "UML network socket";
  68
  69         if((write_fd = socket(PF_UNIX, SOCK_DGRAM, 0)) < 0) {
  70                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not open write %s: %s", device_info, strerror(errno));
  71                 event_exit();
  72                 return false;
  73         }
  74
  75 #ifdef FD_CLOEXEC
  76         fcntl(write_fd, F_SETFD, FD_CLOEXEC);
  77 #endif
  78
  79         setsockopt(write_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof one);
  80
  81         if(fcntl(write_fd, F_SETFL, O_NONBLOCK) < 0) {
  82                 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "fcntl", strerror(errno));
  83                 event_exit();
  84                 return false;
  85         }
  86
  87         if((data_fd = socket(PF_UNIX, SOCK_DGRAM, 0)) < 0) {
  88                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not open data %s: %s", device_info, strerror(errno));
  89                 event_exit();
  90                 return false;
  91         }
  92
  93 #ifdef FD_CLOEXEC
  94         fcntl(data_fd, F_SETFD, FD_CLOEXEC);
  95 #endif
  96
  97         setsockopt(data_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof one);
  98
  99         if(fcntl(data_fd, F_SETFL, O_NONBLOCK) < 0) {
 100                 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "fcntl", strerror(errno));
 101                 event_exit();
 102                 return false;
 103         }
 104
 105         name.zero = 0;
 106         name.pid = getpid();
 107         gettimeofday(&tv, NULL);
 108         name.usecs = tv.tv_usec;
 109         data_sun.sun_family = AF_UNIX;
 110         memcpy(&data_sun.sun_path, &name, sizeof name);
 111
 112         if(bind(data_fd, (struct sockaddr *)&data_sun, sizeof data_sun) < 0) {
 113                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not bind data %s: %s", device_info, strerror(errno));
 114                 event_exit();
 115                 return false;
 116         }
 117
 118         if((listen_fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 119                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not open %s: %s", device_info,
 120                            strerror(errno));
 121                 return false;
 122         }
 123
 124 #ifdef FD_CLOEXEC
 125         fcntl(device_fd, F_SETFD, FD_CLOEXEC);
 126 #endif
 127
 128         setsockopt(listen_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof one);
 129
 130         if(fcntl(listen_fd, F_SETFL, O_NONBLOCK) < 0) {
 131                 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "fcntl", strerror(errno));
 132                 return false;
 133         }
 134
 135         listen_sun.sun_family = AF_UNIX;
 136         strncpy(listen_sun.sun_path, device, sizeof listen_sun.sun_path);
 137         if(bind(listen_fd, (struct sockaddr *)&listen_sun, sizeof listen_sun) < 0) {
 138                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not bind %s to %s: %s", device_info, device, strerror(errno));
 139                 return false;
 140         }
 141
 142         if(listen(listen_fd, 1) < 0) {
 143                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not listen on %s %s: %s", device_info, device, strerror(errno));
 144                 return false;
 145         }
 146
 147         device_fd = listen_fd;
 148         state = 0;
 149
 150         logger(DEBUG_ALWAYS, LOG_INFO, "%s is a %s", device, device_info);
 151
 152         if(routing_mode == RMODE_ROUTER)
 153                 overwrite_mac = true;
 154
 155         return true;
 156 }
 157
 158 void close_device(void) {
 159         if(listen_fd >= 0)
 160                 close(listen_fd);
 161
 162         if(request_fd >= 0)
 163                 close(request_fd);
 164
 165         if(data_fd >= 0)
 166                 close(data_fd);
 167
 168         if(write_fd >= 0)
 169                 close(write_fd);
 170
 171         unlink(device);
 172
 173         free(device);
 174         if(iface) free(iface);
 175 }
 176
 177 static bool read_packet(vpn_packet_t *packet) {
 178         int inlen;
 179
 180         switch(state) {
 181                 case 0: {
 182                         struct sockaddr sa;
 183                         socklen_t salen = sizeof sa;
 184
 185                         request_fd = accept(listen_fd, &sa, &salen);
 186                         if(request_fd < 0) {
 187                                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not accept connection to %s %s: %s", device_info, device, strerror(errno));
 188                                 return false;
 189                         }
 190
 191 #ifdef FD_CLOEXEC
 192                         fcntl(request_fd, F_SETFD, FD_CLOEXEC);
 193 #endif
 194
 195                         if(fcntl(listen_fd, F_SETFL, O_NONBLOCK) < 0) {
 196                                 logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "fcntl", strerror(errno));
 197                                 event_exit();
 198                                 return false;
 199                         }
 200
 201                         close(listen_fd);
 202                         listen_fd = -1;
 203                         device_fd = request_fd;
 204                         state = 1;
 205
 206                         return false;
 207                 }
 208
 209                 case 1: {
 210                         if((inlen = read(request_fd, &request, sizeof request)) != sizeof request) {
 211                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading request from %s %s: %s", device_info,
 212                                            device, strerror(errno));
 213                                 event_exit();
 214                                 return false;
 215                         }
 216
 217                         if(request.magic != 0xfeedface || request.version != 3 || request.type != REQ_NEW_CONTROL) {
 218                                 logger(DEBUG_ALWAYS, LOG_ERR, "Unknown magic %x, version %d, request type %d from %s %s",
 219                                                 request.magic, request.version, request.type, device_info, device);
 220                                 event_exit();
 221                                 return false;
 222                         }
 223
 224                         if(connect(write_fd, &request.sock, sizeof request.sock) < 0) {
 225                                 logger(DEBUG_ALWAYS, LOG_ERR, "Could not bind write %s: %s", device_info, strerror(errno));
 226                                 event_exit();
 227                                 return false;
 228                         }
 229
 230                         write(request_fd, &data_sun, sizeof data_sun);
 231                         device_fd = data_fd;
 232
 233                         logger(DEBUG_ALWAYS, LOG_INFO, "Connection with UML established");
 234
 235                         state = 2;
 236                         return false;
 237                 }
 238
 239                 case 2: {
 240                         if((inlen = read(data_fd, packet->data, MTU)) <= 0) {
 241                                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading from %s %s: %s", device_info,
 242                                            device, strerror(errno));
 243                                 event_exit();
 244                                 return false;
 245                         }
 246
 247                         packet->len = inlen;
 248
 249                         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Read packet of %d bytes from %s", packet->len,
 250                                            device_info);
 251
 252                         return true;
 253                 }
 254
 255                 default:
 256                         logger(DEBUG_ALWAYS, LOG_ERR, "Invalid value for state variable in " __FILE__);
 257                         abort();
 258         }
 259 }
 260
 261 static bool write_packet(vpn_packet_t *packet) {
 262         if(state != 2) {
 263                 logger(DEBUG_TRAFFIC, LOG_DEBUG, "Dropping packet of %d bytes to %s: not connected to UML yet",
 264                                 packet->len, device_info);
 265                 return false;
 266         }
 267
 268         logger(DEBUG_TRAFFIC, LOG_DEBUG, "Writing packet of %d bytes to %s",
 269                            packet->len, device_info);
 270
 271         if(write(write_fd, packet->data, packet->len) < 0) {
 272                 if(errno != EINTR && errno != EAGAIN) {
 273                         logger(DEBUG_ALWAYS, LOG_ERR, "Can't write to %s %s: %s", device_info, device, strerror(errno));
 274                         event_exit();
 275                 }
 276
 277                 return false;
 278         }
 279
 280         return true;
 281 }
 282
 283 const devops_t uml_devops = {
 284         .setup = setup_device,
 285         .close = close_device,
 286         .read = read_packet,
 287         .write = write_packet,
 288 };