usr.sbin/vknetd/vknetd.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 /*
  35  * vknet [-cdU] [-b bridgeN] [-p socket_path] [-t tapN] [address/cidrbits]
  36  *
  37  * Create a named unix-domain socket which userland vkernels can open
  38  * to gain access to a local network.  All connections to the socket
  39  * are bridged together and the local network can also be bridged onto
  40  * a TAP interface by specifying the -t option.
  41  */
  42 #include "vknetd.h"
  43
  44 static ioinfo_t vknet_tap(const char *tapName, const char *bridgeName);
  45 static int vknet_listener(const char *pathName);
  46 static void vknet_acceptor(int net_fd);
  47 static void *vknet_io(void *arg);
  48 static int vknet_connect(const char *pathName);
  49 static void vknet_monitor(int net_fd);
  50 static void usage(void);
  51 static void writepid(void);
  52 static void cleanup(int);
  53
  54 pthread_mutex_t BridgeMutex;
  55
  56 int SecureOpt = 1;
  57 int DebugOpt = 0;
  58 int SetAddrOpt = 0;
  59 const char *pidfile = "/var/run/vknetd.pid";
  60
  61 struct in_addr NetAddress;
  62 struct in_addr NetMask;
  63
  64 int
  65 main(int ac, char **av)
  66 {
  67         const char *pathName = "/var/run/vknet";
  68         const char *tapName = "auto";
  69         const char *bridgeName = NULL;
  70         int net_fd;
  71         int connectOpt = 0;
  72         int c;
  73         ioinfo_t tap_info;
  74         pthread_t dummy_td;
  75
  76         while ((c = getopt(ac, av, "b:cdp:i:t:U")) != -1) {
  77                 switch (c) {
  78                 case 'U':
  79                         SecureOpt = 0;
  80                         break;
  81                 case 'b':
  82                         bridgeName = optarg;
  83                         break;
  84                 case 'd':
  85                         DebugOpt = 1;
  86                         break;
  87                 case 'p':
  88                         pathName = optarg;
  89                         break;
  90                 case 'i':
  91                         pidfile = optarg;
  92                         break;
  93                 case 't':
  94                         tapName = optarg;
  95                         break;
  96                 case 'c':
  97                         connectOpt = 1;
  98                         break;
  99                 default:
 100                         usage();
 101                 }
 102         }
 103         av += optind;
 104         ac -= optind;
 105         if (ac)
 106                 SetAddrOpt = 1;
 107
 108         /*
 109          * Ignore SIGPIPE to prevent write() races against disconnecting
 110          * clients from killing vknetd.  Should be inherited by all I/O
 111          * threads.
 112          */
 113         signal(SIGPIPE, SIG_IGN);
 114
 115         /*
 116          * Special connect/debug mode
 117          */
 118         if (connectOpt) {
 119                 net_fd = vknet_connect(pathName);
 120                 if (net_fd < 0) {
 121                         perror("connect");
 122                         exit(1);
 123                 }
 124                 vknet_monitor(net_fd);
 125                 exit(0);
 126         }
 127
 128         /*
 129          * In secure mode (the default), a network address/mask must be
 130          * specified.  e.g. 10.1.0.0/16.  Any traffic going out the TAP
 131          * interface will be filtered.
 132          *
 133          * If non-secure mode the network address/mask is optional.
 134          */
 135         if (SecureOpt || SetAddrOpt) {
 136                 char *str;
 137                 int masklen;
 138                 u_int32_t mask;
 139
 140                 if (ac == 0 || strchr(av[0], '/') == NULL)
 141                         usage();
 142                 str = strdup(av[0]);
 143                 if (inet_pton(AF_INET, strtok(str, "/"), &NetAddress) <= 0)
 144                         usage();
 145                 masklen = strtoul(strtok(NULL, "/"), NULL, 10);
 146                 mask = (1 << (32 - masklen)) - 1;
 147                 NetMask.s_addr = htonl(~mask);
 148         }
 149
 150         /*
 151          * Normal operation, create the tap/bridge and listener.  This
 152          * part is not threaded.
 153          */
 154         mac_init();
 155
 156         if ((tap_info = vknet_tap(tapName, bridgeName)) == NULL) {
 157                 perror("tap: ");
 158                 exit(1);
 159         }
 160         if ((net_fd = vknet_listener(pathName)) < 0) {
 161                 perror("listener: ");
 162                 exit(1);
 163         }
 164
 165         /*
 166          * Now make us a demon and start the threads going.
 167          */
 168         if (DebugOpt == 0)
 169                 daemon(1, 0);
 170
 171         writepid();
 172
 173         signal(SIGINT, cleanup);
 174         signal(SIGHUP, cleanup);
 175         signal(SIGTERM, cleanup);
 176
 177         pthread_mutex_init(&BridgeMutex, NULL);
 178         pthread_create(&dummy_td, NULL, vknet_io, tap_info);
 179         vknet_acceptor(net_fd);
 180
 181         exit(0);
 182 }
 183
 184 #define TAPDEV_MINOR(x) ((int)((x) & 0xffff00ff))
 185
 186 static ioinfo_t
 187 vknet_tap(const char *tapName, const char *bridgeName)
 188 {
 189         struct ifreq ifr;
 190         struct ifaliasreq ifra;
 191         struct stat st;
 192         char *buf = NULL;
 193         int tap_fd;
 194         int tap_unit;
 195         int i;
 196         int s;
 197         int flags;
 198         ioinfo_t info;
 199
 200         if (strcmp(tapName, "auto") == 0) {
 201                 for (i = 0; ; ++i) {
 202                         asprintf(&buf, "/dev/tap%d", i);
 203                         tap_fd = open(buf, O_RDWR | O_NONBLOCK);
 204                         free(buf);
 205                         if (tap_fd >= 0 || errno == ENOENT)
 206                                 break;
 207                 }
 208         } else if (strncmp(tapName, "tap", 3) == 0) {
 209                 asprintf(&buf, "/dev/%s", tapName);
 210                 tap_fd = open(buf, O_RDWR | O_NONBLOCK);
 211                 free(buf);
 212         } else {
 213                 tap_fd = open(tapName, O_RDWR | O_NONBLOCK);
 214         }
 215         if (tap_fd < 0)
 216                 return(NULL);
 217
 218         /*
 219          * Figure out the tap unit number
 220          */
 221         if (fstat(tap_fd, &st) < 0) {
 222                 close(tap_fd);
 223                 return(NULL);
 224         }
 225         tap_unit = TAPDEV_MINOR(st.st_rdev);
 226
 227         /*
 228          * Setup for ioctls
 229          */
 230         fcntl(tap_fd, F_SETFL, 0);
 231         bzero(&ifr, sizeof(ifr));
 232         bzero(&ifra, sizeof(ifra));
 233         snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "tap%d", tap_unit);
 234         snprintf(ifra.ifra_name, sizeof(ifra.ifra_name), "tap%d", tap_unit);
 235
 236         s = socket(AF_INET, SOCK_DGRAM, 0);
 237
 238         /*
 239          * Set the interface address if in Secure mode.
 240          */
 241         if (SetAddrOpt) {
 242                 struct sockaddr_in *in;
 243
 244                 in = (void *)&ifra.ifra_addr;
 245                 in->sin_family = AF_INET;
 246                 in->sin_len = sizeof(ifra.ifra_addr);
 247                 in->sin_addr = NetAddress;
 248                 in = (void *)&ifra.ifra_mask;
 249                 in->sin_family = AF_INET;
 250                 in->sin_len = sizeof(ifra.ifra_mask);
 251                 in->sin_addr = NetMask;
 252                 if (ioctl(s, SIOCAIFADDR, &ifra) < 0) {
 253                         perror("Unable to set address on tap interface");
 254                         exit(1);
 255                 }
 256         }
 257
 258         /*
 259          * Turn up the interface
 260          */
 261         flags = IFF_UP;
 262         if (ioctl(s, SIOCGIFFLAGS, &ifr) >= 0) {
 263                 bzero(&ifr, sizeof(ifr));
 264                 snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "tap%d", tap_unit);
 265                 ifr.ifr_flags |= flags & 0xFFFF;
 266                 ifr.ifr_flagshigh |= flags >> 16;
 267                 if (ioctl(s, SIOCSIFFLAGS, &ifr) < 0) {
 268                         perror("Unable to set IFF_UP on tap interface");
 269                         exit(1);
 270                 }
 271         }
 272
 273         if (bridgeName) {
 274                 struct ifbreq ifbr;
 275                 struct ifdrv ifd;
 276
 277                 /*
 278                  * Create the bridge if necessary.
 279                  */
 280                 bzero(&ifr, sizeof(ifr));
 281                 snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s", bridgeName);
 282                 if (ioctl(s, SIOCIFCREATE, &ifr) < 0) {
 283                         if (errno != EEXIST) {
 284                                 perror("Unable to create bridge interface");
 285                                 exit(1);
 286                         }
 287                 }
 288
 289
 290                 /*
 291                  * Add the tap interface to the bridge
 292                  */
 293                 bzero(&ifbr, sizeof(ifbr));
 294                 snprintf(ifbr.ifbr_ifsname, sizeof(ifbr.ifbr_ifsname),
 295                          "tap%d", tap_unit);
 296
 297                 bzero(&ifd, sizeof(ifd));
 298                 snprintf(ifd.ifd_name, sizeof(ifd.ifd_name), "%s", bridgeName);
 299                 ifd.ifd_cmd = BRDGADD;
 300                 ifd.ifd_len = sizeof(ifbr);
 301                 ifd.ifd_data = &ifbr;
 302
 303                 if (ioctl(s, SIOCSDRVSPEC, &ifd) < 0) {
 304                         if (errno != EEXIST) {
 305                                 perror("Unable to add tap ifc to bridge!");
 306                                 exit(1);
 307                         }
 308                 }
 309         }
 310
 311         close(s);
 312         info = malloc(sizeof(*info));
 313         bzero(info, sizeof(*info));
 314         info->fd = tap_fd;
 315         info->istap = 1;
 316         return(info);
 317 }
 318
 319 #undef TAPDEV_MINOR
 320
 321 static int
 322 vknet_listener(const char *pathName)
 323 {
 324         struct sockaddr_un sunx;
 325         int net_fd;
 326         int len;
 327         gid_t gid;
 328         struct group *grp;
 329
 330         /*
 331          * Group access to our named unix domain socket.
 332          */
 333         if ((grp = getgrnam("vknet")) == NULL) {
 334                 fprintf(stderr, "The 'vknet' group must exist\n");
 335                 exit(1);
 336         }
 337         gid = grp->gr_gid;
 338         endgrent();
 339
 340         /*
 341          * Socket setup
 342          */
 343         snprintf(sunx.sun_path, sizeof(sunx.sun_path), "%s", pathName);
 344         len = offsetof(struct sockaddr_un, sun_path[strlen(sunx.sun_path)]);
 345         ++len;  /* include nul */
 346         sunx.sun_family = AF_UNIX;
 347         sunx.sun_len = len;
 348
 349         net_fd = socket(AF_UNIX, SOCK_SEQPACKET, 0);
 350         if (net_fd < 0)
 351                 return(-1);
 352         remove(pathName);
 353         if (bind(net_fd, (void *)&sunx, len) < 0) {
 354                 close(net_fd);
 355                 return(-1);
 356         }
 357         if (listen(net_fd, 1024) < 0) {
 358                 close(net_fd);
 359                 return(-1);
 360         }
 361         if (chown(pathName, (uid_t)-1, gid) < 0) {
 362                 close(net_fd);
 363                 return(-1);
 364         }
 365         if (chmod(pathName, 0660) < 0) {
 366                 close(net_fd);
 367                 return(-1);
 368         }
 369         return(net_fd);
 370 }
 371
 372 static
 373 void
 374 vknet_acceptor(int net_fd)
 375 {
 376         struct sockaddr_un sunx;
 377         pthread_t dummy_td;
 378         int sunx_len;
 379         int rfd;
 380         ioinfo_t info;
 381
 382         for (;;) {
 383                 sunx_len = sizeof(sunx);
 384                 rfd = accept(net_fd, (void *)&sunx, &sunx_len);
 385                 if (rfd < 0)
 386                         break;
 387                 info = malloc(sizeof(*info));
 388                 bzero(info, sizeof(*info));
 389                 info->fd = rfd;
 390                 info->istap = 0;
 391                 pthread_create(&dummy_td, NULL, vknet_io, info);
 392         }
 393 }
 394
 395 /*
 396  * This I/O thread implements the core of the bridging code.
 397  */
 398 static
 399 void *
 400 vknet_io(void *arg)
 401 {
 402         ioinfo_t info = arg;
 403         bridge_t bridge;
 404         u_int8_t *pkt;
 405         int bytes;
 406
 407         pthread_detach(pthread_self());
 408
 409         /*
 410          * Assign as a bridge slot using our thread id.
 411          */
 412         pthread_mutex_lock(&BridgeMutex);
 413         bridge = bridge_add(info);
 414         pthread_mutex_unlock(&BridgeMutex);
 415
 416         /*
 417          * Read packet loop.  Writing is handled by the bridge code.
 418          */
 419         pkt = malloc(MAXPKT);
 420         while ((bytes = read(info->fd, pkt, MAXPKT)) > 0) {
 421                 pthread_mutex_lock(&BridgeMutex);
 422                 bridge_packet(bridge, pkt, bytes);
 423                 pthread_mutex_unlock(&BridgeMutex);
 424         }
 425
 426         /*
 427          * Cleanup
 428          */
 429         pthread_mutex_lock(&BridgeMutex);
 430         bridge_del(bridge);
 431         pthread_mutex_unlock(&BridgeMutex);
 432
 433         close(info->fd);
 434         free(pkt);
 435         pthread_exit(NULL);
 436 }
 437
 438 /*
 439  * Debugging
 440  */
 441 static int
 442 vknet_connect(const char *pathName)
 443 {
 444         struct sockaddr_un sunx;
 445         int len;
 446         int net_fd;
 447
 448         snprintf(sunx.sun_path, sizeof(sunx.sun_path), "%s", pathName);
 449         len = offsetof(struct sockaddr_un, sun_path[strlen(sunx.sun_path)]);
 450         ++len;  /* include nul */
 451         sunx.sun_family = AF_UNIX;
 452         sunx.sun_len = len;
 453
 454         net_fd = socket(AF_UNIX, SOCK_SEQPACKET, 0);
 455         if (net_fd < 0)
 456                 return(-1);
 457         if (connect(net_fd, (void *)&sunx, len) < 0) {
 458                 close(net_fd);
 459                 return(-1);
 460         }
 461         return(net_fd);
 462 }
 463
 464 static void
 465 vknet_monitor(int net_fd)
 466 {
 467         u_int8_t *pkt;
 468         int bytes;
 469         int i;
 470
 471         pkt = malloc(MAXPKT);
 472         while ((bytes = read(net_fd, pkt, MAXPKT)) > 0) {
 473                 printf("%02x:%02x:%02x:%02x:%02x:%02x <- "
 474                        "%02x:%02x:%02x:%02x:%02x:%02x",
 475                        pkt[0], pkt[1], pkt[2], pkt[3], pkt[4], pkt[5],
 476                        pkt[6], pkt[7], pkt[8], pkt[9], pkt[10], pkt[11]);
 477                 for (i = 12; i < bytes; ++i) {
 478                         if (((i - 12) & 15) == 0) {
 479                                 printf("\n\t");
 480                         }
 481                         printf(" %02x", pkt[i]);
 482                 }
 483                 printf("\n");
 484         }
 485         free(pkt);
 486 }
 487
 488 /*
 489  * Misc
 490  */
 491 static void
 492 writepid(void)
 493 {
 494         FILE *pf;
 495
 496         if ((pf = fopen(pidfile, "w+")) == NULL)
 497                 errx(1, "Failed to create pidfile %s", pidfile);
 498
 499         if ((fprintf(pf, "%d\n", getpid())) < 1)
 500                 err(1, "fprintf");
 501
 502         fclose(pf);
 503 }
 504
 505 static void
 506 cleanup(int __unused sig)
 507 {
 508         if (pidfile)
 509                 unlink(pidfile);
 510 }
 511
 512 static
 513 void
 514 usage(void)
 515 {
 516         fprintf(stderr, "usage: vknet [-cdU] [-b bridgeN] [-p socket_path] [-i pidfile] [-t tapN] [address/cidrbits]\n");
 517         fprintf(stderr, "address/cidrbits must be specified in default secure mode.\n");
 518         exit(1);
 519 }
 520