usr.bin/vknet/vknet.c

   1 /*
   2  * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * $DragonFly: src/usr.bin/vknet/vknet.c,v 1.1 2008/05/27 23:26:38 dillon Exp $
  35  */
  36 /*
  37  * vknet [-C] [-b local-bridge] [-B remote-bridge] [-r delay[:retries]]
  38  *       local-spec [user@]remote[:remote-spec]
  39  * vknet -S [-b local-bridge] local-spec        (server mode)
  40  *
  41  * Connect a SOCK_SEQPACKET socket or TUN device on the local host with
  42  * a SOCK_SEQPACKET socket or TUN device on the remote host through a SSH
  43  * connection.  When a TUN device is specified it may be optionally bridged.
  44  *
  45  * This program expects packetized reads and writes on the local and remote
  46  * sides and will re-block them over the SSH stream.
  47  */
  48
  49 #include "vknet.h"
  50
  51 static void vknet_blastaway(ioinfo_t ios, ioinfo_t iod);
  52 static void *vknet_stream(void *arg);
  53 static void vknet_connect(ioinfo_t ios,
  54                           const char *localSide, const char *localBridge);
  55 static void vknet_execssh(int fdin, int fdout, int compressOpt,
  56                           const char *remoteSide, const char *remoteBridge);
  57 static void usage(void);
  58
  59 pthread_mutex_t MasterLock;
  60
  61 int
  62 main(int ac, char **av)
  63 {
  64         int compressOpt = 0;
  65         int remoteOpt = 0;
  66         const char *localBridge = NULL;
  67         const char *remoteBridge = NULL;
  68         const char *localSide;
  69         const char *remoteSide;
  70         char *ptr;
  71         int c;
  72         int retriesOpt = -1;
  73         int timeoutOpt = -1;
  74         struct ioinfo ios;
  75         struct ioinfo iod;
  76
  77         while ((c = getopt(ac, av, "b:B:r:CS")) != -1) {
  78                 switch (c) {
  79                 case 'b':
  80                         localBridge = optarg;
  81                         break;
  82                 case 'B':
  83                         remoteBridge = optarg;
  84                         break;
  85                 case 'r':
  86                         timeoutOpt = strtol(optarg, &ptr, 0);
  87                         if (ptr && *ptr == ':')
  88                                 retriesOpt = strtol(ptr + 1, NULL, 0);
  89                         break;
  90                 case 'S':
  91                         remoteOpt = 1;
  92                         break;
  93                 case 'C':
  94                         compressOpt = 1;
  95                         break;
  96                 default:
  97                         usage();
  98                 }
  99         }
 100         av += optind;
 101         ac -= optind;
 102
 103         /*
 104          * Local and remote arguments.
 105          */
 106         if (remoteOpt) {
 107                 if (ac != 1)
 108                         usage();
 109                 localSide = av[0];
 110                 remoteSide = NULL;
 111         } else {
 112                 if (ac != 2)
 113                         usage();
 114                 localSide = av[0];
 115                 remoteSide = av[1];
 116         }
 117
 118         pthread_mutex_init(&MasterLock, NULL);
 119
 120 retry:
 121         /*
 122          * Setup connections
 123          */
 124         vknet_connect(&ios, localSide, localBridge);
 125         if (remoteOpt) {
 126                 iod.fdin = 0;
 127                 iod.fdout = 1;
 128         } else {
 129                 int fds[2];
 130
 131                 if (pipe(fds) < 0) {
 132                         perror("pipe");
 133                         exit(1);
 134                 }
 135                 vknet_execssh(fds[1], fds[1], compressOpt,
 136                               remoteSide, remoteBridge);
 137                 close(fds[1]);
 138                 iod.fdin = fds[0];
 139                 iod.fdout = fds[0];
 140         }
 141
 142         /*
 143          * Blast away, timeout/retry on failure
 144          */
 145         vknet_blastaway(&ios, &iod);
 146
 147         /*
 148          * Handle timeout/retries
 149          */
 150         if (timeoutOpt >= 0 && retriesOpt != 0) {
 151                 printf("timeout %d retries %d\n", timeoutOpt, retriesOpt);
 152                 if (timeoutOpt > 0)
 153                         sleep(timeoutOpt);
 154                 if (retriesOpt > 0)
 155                         --retriesOpt;
 156                 goto retry;
 157         }
 158         exit(0);
 159 }
 160
 161 static void
 162 vknet_blastaway(ioinfo_t ios, ioinfo_t iod)
 163 {
 164         struct streaminfo stream1;
 165         struct streaminfo stream2;
 166
 167         pthread_mutex_lock(&MasterLock);
 168         stream1.fdin = ios->fdin;
 169         stream1.fdout = iod->fdout;
 170         stream1.flags = REBLOCK_OUT;
 171         stream1.other = &stream2;
 172         stream2.fdin = iod->fdin;
 173         stream2.fdout = ios->fdout;
 174         stream2.flags = REBLOCK_IN;
 175         stream2.other = &stream1;
 176         pthread_create(&stream1.thread, NULL, vknet_stream, &stream1);
 177         pthread_create(&stream2.thread, NULL, vknet_stream, &stream2);
 178         pthread_mutex_unlock(&MasterLock);
 179         pthread_join(stream1.thread, NULL);
 180         pthread_join(stream2.thread, NULL);
 181 }
 182
 183 /*
 184  * Transfer packets between two descriptors
 185  */
 186 static
 187 void *
 188 vknet_stream(void *arg)
 189 {
 190         streaminfo_t stream = arg;
 191         struct blkhead head;
 192         u_int8_t *pkt;
 193         int bytes;
 194         int n;
 195         int r;
 196
 197         /*
 198          * Synchronize with master thread, then loop
 199          */
 200         pthread_mutex_lock(&MasterLock);
 201         pthread_mutex_unlock(&MasterLock);
 202
 203         pkt = malloc(MAXPKT);
 204
 205         for (;;) {
 206                 /*
 207                  * Input side
 208                  */
 209                 if (stream->flags & REBLOCK_IN) {
 210                         bytes = sizeof(head);
 211                         for (n = 0; n < bytes; n += r) {
 212                                 r = read(stream->fdin, (char *)&head + n,
 213                                          bytes - n);
 214                                 if (r <= 0)
 215                                         break;
 216                         }
 217                         if (n != bytes)
 218                                 break;
 219                         if (le32toh(head.magic) != MAGIC)
 220                                 break;
 221                         bytes = le32toh(head.bytes);
 222                         if (bytes <= 0 || bytes > MAXPKT)
 223                                 break;
 224                         for (n = 0; n < bytes; n += r) {
 225                                 r = read(stream->fdin, pkt + n, bytes - n);
 226                                 if (r <= 0)
 227                                         break;
 228                         }
 229                         if (n != bytes)
 230                                 break;
 231                 } else {
 232                         bytes = read(stream->fdin, pkt, MAXPKT);
 233                         if (bytes <= 0)
 234                                 break;
 235                 }
 236
 237                 /*
 238                  * Output side
 239                  */
 240                 if (stream->flags & REBLOCK_OUT) {
 241                         head.magic = htole32(MAGIC);
 242                         head.bytes = htole32(bytes);
 243                         if (write(stream->fdout, &head, sizeof(head)) != sizeof(head))
 244                                 break;
 245                         if (write(stream->fdout, pkt, bytes) != bytes)
 246                                 break;
 247                 } else {
 248                         if (write(stream->fdout, pkt, bytes) != bytes)
 249                                 break;
 250                 }
 251         }
 252         free(pkt);
 253         close(stream->fdin);
 254         close(stream->fdout);
 255         pthread_cancel(stream->other->thread);
 256         pthread_exit(NULL);
 257 }
 258
 259 /*
 260  * vknet_connect() - Connect to local side, optionally find or bridge the tap
 261  *                   interface.
 262  */
 263 static void
 264 vknet_connect(ioinfo_t io, const char *localSide, const char *localBridge)
 265 {
 266         struct ifreq ifr;
 267         struct ifaliasreq ifra;
 268         char *buf = NULL;
 269         int tap_fd;
 270         int tap_unit;
 271         int i;
 272         int s;
 273         int flags;
 274
 275         tap_unit = -1;
 276         tap_fd = -1;
 277
 278         if (strcmp(localSide, "auto") == 0) {
 279                 for (i = 0; ; ++i) {
 280                         asprintf(&buf, "/dev/tap%d", i);
 281                         tap_fd = open(buf, O_RDWR | O_NONBLOCK);
 282                         free(buf);
 283                         if (tap_fd >= 0 || errno == ENOENT) {
 284                                 tap_unit = i;
 285                                 break;
 286                         }
 287                 }
 288         } else if (strncmp(localSide, "tap", 3) == 0) {
 289                 asprintf(&buf, "/dev/%s", localSide);
 290                 tap_fd = open(buf, O_RDWR | O_NONBLOCK);
 291                 tap_unit = strtol(localSide + 3, NULL, 10);
 292                 free(buf);
 293         } else if ((tap_fd = open(localSide, O_RDWR | O_NONBLOCK)) >= 0) {
 294                 const char *ptr = localSide + strlen(localSide);
 295                 while (ptr > localSide && ptr[-1] >= '0' && ptr[-1] <= '9')
 296                         --ptr;
 297                 tap_unit = strtol(ptr, NULL, 10);
 298         } else {
 299                 struct sockaddr_un sunx;
 300                 int len;
 301
 302                 snprintf(sunx.sun_path, sizeof(sunx.sun_path), "%s", localSide);
 303                 len = offsetof(struct sockaddr_un,
 304                                sun_path[strlen(sunx.sun_path)]);
 305                 ++len;  /* include nul */
 306                 sunx.sun_family = AF_UNIX;
 307                 sunx.sun_len = len;
 308
 309                 tap_fd = socket(AF_UNIX, SOCK_SEQPACKET, 0);
 310                 if (tap_fd >= 0)         {
 311                         if (connect(tap_fd, (void *)&sunx, len) < 0) {
 312                                 close(tap_fd);
 313                                 tap_fd = -1;
 314                         }
 315                 }
 316         }
 317
 318         if (tap_fd < 0) {
 319                 err(1, "Unable to connect to %s", localSide);
 320                 /* NOT REACHED */
 321         }
 322
 323         fcntl(tap_fd, F_SETFL, 0);
 324         io->fdin = tap_fd;
 325         io->fdout = tap_fd;
 326
 327         /*
 328          * If this isn't a TAP device we are done.
 329          */
 330         if (tap_unit < 0)
 331                 return;
 332
 333         /*
 334          * Bring up the TAP interface
 335          */
 336         bzero(&ifr, sizeof(ifr));
 337         bzero(&ifra, sizeof(ifra));
 338         snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "tap%d", tap_unit);
 339         snprintf(ifra.ifra_name, sizeof(ifra.ifra_name), "tap%d", tap_unit);
 340
 341         s = socket(AF_INET, SOCK_DGRAM, 0);
 342
 343 #if 0
 344         /*
 345          * Set the interface address if in Secure mode.
 346          */
 347         if (SecureOpt) {
 348                 struct sockaddr_in *in;
 349
 350                 in = (void *)&ifra.ifra_addr;
 351                 in->sin_family = AF_INET;
 352                 in->sin_len = sizeof(ifra.ifra_addr);
 353                 in->sin_addr = NetAddress;
 354                 in = (void *)&ifra.ifra_mask;
 355                 in->sin_family = AF_INET;
 356                 in->sin_len = sizeof(ifra.ifra_mask);
 357                 in->sin_addr = NetMask;
 358                 if (ioctl(s, SIOCAIFADDR, &ifra) < 0) {
 359                         perror("Unable to set address on tap interface");
 360                         exit(1);
 361                 }
 362         }
 363 #endif
 364
 365         /*
 366          * Turn up the interface
 367          */
 368         flags = IFF_UP;
 369         if (ioctl(s, SIOCGIFFLAGS, &ifr) >= 0) {
 370                 bzero(&ifr, sizeof(ifr));
 371                 snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "tap%d", tap_unit);
 372                 ifr.ifr_flags |= flags & 0xFFFF;
 373                 ifr.ifr_flagshigh |= flags >> 16;
 374                 if (ioctl(s, SIOCSIFFLAGS, &ifr) < 0) {
 375                         perror("Unable to set IFF_UP on tap interface");
 376                         exit(1);
 377                 }
 378         }
 379
 380         /*
 381          * If a bridge was specified associate the tap interface with the
 382          * bridge.
 383          */
 384         if (localBridge) {
 385                 struct ifbreq ifbr;
 386                 struct ifdrv ifd;
 387
 388                 /*
 389                  * Create the bridge if necessary.
 390                  */
 391                 bzero(&ifr, sizeof(ifr));
 392                 snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s", localBridge);
 393                 if (ioctl(s, SIOCIFCREATE, &ifr) < 0) {
 394                         if (errno != EEXIST) {
 395                                 perror("Unable to create bridge interface");
 396                                 exit(1);
 397                         }
 398                 }
 399
 400
 401                 /*
 402                  * Add the tap interface to the bridge
 403                  */
 404                 bzero(&ifbr, sizeof(ifbr));
 405                 snprintf(ifbr.ifbr_ifsname, sizeof(ifbr.ifbr_ifsname),
 406                          "tap%d", tap_unit);
 407
 408                 bzero(&ifd, sizeof(ifd));
 409                 snprintf(ifd.ifd_name, sizeof(ifd.ifd_name), "%s", localBridge);
 410                 ifd.ifd_cmd = BRDGADD;
 411                 ifd.ifd_len = sizeof(ifbr);
 412                 ifd.ifd_data = &ifbr;
 413
 414                 if (ioctl(s, SIOCSDRVSPEC, &ifd) < 0) {
 415                         if (errno != EEXIST) {
 416                                 perror("Unable to add tap ifc to bridge!");
 417                                 exit(1);
 418                         }
 419                 }
 420         }
 421         close(s);
 422 }
 423
 424 /*
 425  * Connect to the remote machine with ssh and set up a stream
 426  */
 427 static void
 428 vknet_execssh(int fdin, int fdout, int compressOpt,
 429               const char *remoteSide, const char *remoteBridge)
 430 {
 431         char *remoteHost;
 432         char *remotePath;
 433         const char *av[24];
 434         int ac;
 435         pid_t pid;
 436
 437         /*
 438          * Fork / parent returns.
 439          */
 440         if ((pid = fork()) > 0)
 441                 return;
 442         if (pid < 0) {
 443                 perror("fork");
 444                 exit(1);
 445         }
 446
 447         /*
 448          * Setup stdin, stdout
 449          */
 450         assert(fdin > 2);
 451         assert(fdout > 2);
 452         dup2(fdin, 0);
 453         dup2(fdout, 1);
 454         close(fdin);
 455         close(fdout);
 456
 457         /*
 458          * Set up arguments
 459          */
 460         remoteHost = strdup(remoteSide);
 461         if ((remotePath = strchr(remoteHost, ':')) != NULL) {
 462                 *remotePath++ = 0;
 463         } else {
 464                 remotePath = strdup("/var/run/vknet");
 465         }
 466         ac = 0;
 467         av[ac++] = "ssh";
 468         if (compressOpt)
 469                 av[ac++] = "-C";
 470         av[ac++] = "-x";
 471         av[ac++] = "-T";
 472         av[ac++] = "-e";
 473         av[ac++] = "none";
 474         av[ac++] = remoteHost;
 475         av[ac++] = "exec";
 476         av[ac++] = "vknet";
 477         av[ac++] = "-S";
 478         if (remoteBridge) {
 479                 av[ac++] = "-b";
 480                 av[ac++] = remoteBridge;
 481         }
 482         av[ac++] = remotePath;
 483         av[ac++] = NULL;
 484         execv("/usr/bin/ssh", (void *)av);
 485 }
 486
 487 /*
 488  * Misc
 489  */
 490 static
 491 void
 492 usage(void)
 493 {
 494         fprintf(stderr,
 495                 "vknet [-C] [-b local-bridge] [-B remote-bridge] [-r delay[:retries]]\n"
 496                 "      local-spec [user@]remote[:remote-spec]\n"
 497                 "vknet -S [-b local-bridge] local-spec\n"
 498         );
 499         exit(1);
 500 }
 501