tests/vhost-user-bridge.c

   1 /*
   2  * Vhost User Bridge
   3  *
   4  * Copyright (c) 2015 Red Hat, Inc.
   5  *
   6  * Authors:
   7  *  Victor Kaplansky <victork@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or
  10  * later.  See the COPYING file in the top-level directory.
  11  */
  12
  13 /*
  14  * TODO:
  15  *     - main should get parameters from the command line.
  16  *     - implement all request handlers. Still not implemented:
  17  *          vubr_get_queue_num_exec()
  18  *          vubr_send_rarp_exec()
  19  *     - test for broken requests and virtqueue.
  20  *     - implement features defined by Virtio 1.0 spec.
  21  *     - support mergeable buffers and indirect descriptors.
  22  *     - implement clean shutdown.
  23  *     - implement non-blocking writes to UDP backend.
  24  *     - implement polling strategy.
  25  *     - implement clean starting/stopping of vq processing
  26  *     - implement clean starting/stopping of used and buffers
  27  *       dirty page logging.
  28  */
  29
  30 #define _FILE_OFFSET_BITS 64
  31
  32 #include "qemu/osdep.h"
  33 #include "qemu/atomic.h"
  34 #include "qemu/ctype.h"
  35 #include "qemu/iov.h"
  36 #include "standard-headers/linux/virtio_net.h"
  37 #include "libvhost-user.h"
  38
  39 #define VHOST_USER_BRIDGE_DEBUG 1
  40
  41 #define DPRINT(...) \
  42     do { \
  43         if (VHOST_USER_BRIDGE_DEBUG) { \
  44             printf(__VA_ARGS__); \
  45         } \
  46     } while (0)
  47
  48 enum {
  49     VHOST_USER_BRIDGE_MAX_QUEUES = 8,
  50 };
  51
  52 typedef void (*CallbackFunc)(int sock, void *ctx);
  53
  54 typedef struct Event {
  55     void *ctx;
  56     CallbackFunc callback;
  57 } Event;
  58
  59 typedef struct Dispatcher {
  60     int max_sock;
  61     fd_set fdset;
  62     Event events[FD_SETSIZE];
  63 } Dispatcher;
  64
  65 typedef struct VubrDev {
  66     VuDev vudev;
  67     Dispatcher dispatcher;
  68     int backend_udp_sock;
  69     struct sockaddr_in backend_udp_dest;
  70     int hdrlen;
  71     int sock;
  72     int ready;
  73     int quit;
  74     struct {
  75         int fd;
  76         void *addr;
  77         pthread_t thread;
  78     } notifier;
  79 } VubrDev;
  80
  81 static void
  82 vubr_die(const char *s)
  83 {
  84     perror(s);
  85     exit(1);
  86 }
  87
  88 static int
  89 dispatcher_init(Dispatcher *dispr)
  90 {
  91     FD_ZERO(&dispr->fdset);
  92     dispr->max_sock = -1;
  93     return 0;
  94 }
  95
  96 static int
  97 dispatcher_add(Dispatcher *dispr, int sock, void *ctx, CallbackFunc cb)
  98 {
  99     if (sock >= FD_SETSIZE) {
 100         fprintf(stderr,
 101                 "Error: Failed to add new event. sock %d should be less than %d\n",
 102                 sock, FD_SETSIZE);
 103         return -1;
 104     }
 105
 106     dispr->events[sock].ctx = ctx;
 107     dispr->events[sock].callback = cb;
 108
 109     FD_SET(sock, &dispr->fdset);
 110     if (sock > dispr->max_sock) {
 111         dispr->max_sock = sock;
 112     }
 113     DPRINT("Added sock %d for watching. max_sock: %d\n",
 114            sock, dispr->max_sock);
 115     return 0;
 116 }
 117
 118 static int
 119 dispatcher_remove(Dispatcher *dispr, int sock)
 120 {
 121     if (sock >= FD_SETSIZE) {
 122         fprintf(stderr,
 123                 "Error: Failed to remove event. sock %d should be less than %d\n",
 124                 sock, FD_SETSIZE);
 125         return -1;
 126     }
 127
 128     FD_CLR(sock, &dispr->fdset);
 129     DPRINT("Sock %d removed from dispatcher watch.\n", sock);
 130     return 0;
 131 }
 132
 133 /* timeout in us */
 134 static int
 135 dispatcher_wait(Dispatcher *dispr, uint32_t timeout)
 136 {
 137     struct timeval tv;
 138     tv.tv_sec = timeout / 1000000;
 139     tv.tv_usec = timeout % 1000000;
 140
 141     fd_set fdset = dispr->fdset;
 142
 143     /* wait until some of sockets become readable. */
 144     int rc = select(dispr->max_sock + 1, &fdset, 0, 0, &tv);
 145
 146     if (rc == -1) {
 147         vubr_die("select");
 148     }
 149
 150     /* Timeout */
 151     if (rc == 0) {
 152         return 0;
 153     }
 154
 155     /* Now call callback for every ready socket. */
 156
 157     int sock;
 158     for (sock = 0; sock < dispr->max_sock + 1; sock++) {
 159         /* The callback on a socket can remove other sockets from the
 160          * dispatcher, thus we have to check that the socket is
 161          * still not removed from dispatcher's list
 162          */
 163         if (FD_ISSET(sock, &fdset) && FD_ISSET(sock, &dispr->fdset)) {
 164             Event *e = &dispr->events[sock];
 165             e->callback(sock, e->ctx);
 166         }
 167     }
 168
 169     return 0;
 170 }
 171
 172 static void
 173 vubr_handle_tx(VuDev *dev, int qidx)
 174 {
 175     VuVirtq *vq = vu_get_queue(dev, qidx);
 176     VubrDev *vubr = container_of(dev, VubrDev, vudev);
 177     int hdrlen = vubr->hdrlen;
 178     VuVirtqElement *elem = NULL;
 179
 180     assert(qidx % 2);
 181
 182     for (;;) {
 183         ssize_t ret;
 184         unsigned int out_num;
 185         struct iovec sg[VIRTQUEUE_MAX_SIZE], *out_sg;
 186
 187         elem = vu_queue_pop(dev, vq, sizeof(VuVirtqElement));
 188         if (!elem) {
 189             break;
 190         }
 191
 192         out_num = elem->out_num;
 193         out_sg = elem->out_sg;
 194         if (out_num < 1) {
 195             fprintf(stderr, "virtio-net header not in first element\n");
 196             break;
 197         }
 198         if (VHOST_USER_BRIDGE_DEBUG) {
 199             iov_hexdump(out_sg, out_num, stderr, "TX:", 1024);
 200         }
 201
 202         if (hdrlen) {
 203             unsigned sg_num = iov_copy(sg, ARRAY_SIZE(sg),
 204                                        out_sg, out_num,
 205                                        hdrlen, -1);
 206             out_num = sg_num;
 207             out_sg = sg;
 208         }
 209
 210         struct msghdr msg = {
 211             .msg_name = (struct sockaddr *) &vubr->backend_udp_dest,
 212             .msg_namelen = sizeof(struct sockaddr_in),
 213             .msg_iov = out_sg,
 214             .msg_iovlen = out_num,
 215         };
 216         do {
 217             ret = sendmsg(vubr->backend_udp_sock, &msg, 0);
 218         } while (ret == -1 && (errno == EAGAIN || errno == EINTR));
 219
 220         if (ret == -1) {
 221             vubr_die("sendmsg()");
 222         }
 223
 224         vu_queue_push(dev, vq, elem, 0);
 225         vu_queue_notify(dev, vq);
 226
 227         free(elem);
 228         elem = NULL;
 229     }
 230
 231     free(elem);
 232 }
 233
 234
 235 /* this function reverse the effect of iov_discard_front() it must be
 236  * called with 'front' being the original struct iovec and 'bytes'
 237  * being the number of bytes you shaved off
 238  */
 239 static void
 240 iov_restore_front(struct iovec *front, struct iovec *iov, size_t bytes)
 241 {
 242     struct iovec *cur;
 243
 244     for (cur = front; cur != iov; cur++) {
 245         assert(bytes >= cur->iov_len);
 246         bytes -= cur->iov_len;
 247     }
 248
 249     cur->iov_base -= bytes;
 250     cur->iov_len += bytes;
 251 }
 252
 253 static void
 254 iov_truncate(struct iovec *iov, unsigned iovc, size_t bytes)
 255 {
 256     unsigned i;
 257
 258     for (i = 0; i < iovc; i++, iov++) {
 259         if (bytes < iov->iov_len) {
 260             iov->iov_len = bytes;
 261             return;
 262         }
 263
 264         bytes -= iov->iov_len;
 265     }
 266
 267     assert(!"couldn't truncate iov");
 268 }
 269
 270 static void
 271 vubr_backend_recv_cb(int sock, void *ctx)
 272 {
 273     VubrDev *vubr = (VubrDev *) ctx;
 274     VuDev *dev = &vubr->vudev;
 275     VuVirtq *vq = vu_get_queue(dev, 0);
 276     VuVirtqElement *elem = NULL;
 277     struct iovec mhdr_sg[VIRTQUEUE_MAX_SIZE];
 278     struct virtio_net_hdr_mrg_rxbuf mhdr;
 279     unsigned mhdr_cnt = 0;
 280     int hdrlen = vubr->hdrlen;
 281     int i = 0;
 282     struct virtio_net_hdr hdr = {
 283         .flags = 0,
 284         .gso_type = VIRTIO_NET_HDR_GSO_NONE
 285     };
 286
 287     DPRINT("\n\n   ***   IN UDP RECEIVE CALLBACK    ***\n\n");
 288     DPRINT("    hdrlen = %d\n", hdrlen);
 289
 290     if (!vu_queue_enabled(dev, vq) ||
 291         !vu_queue_started(dev, vq) ||
 292         !vu_queue_avail_bytes(dev, vq, hdrlen, 0)) {
 293         DPRINT("Got UDP packet, but no available descriptors on RX virtq.\n");
 294         return;
 295     }
 296
 297     while (1) {
 298         struct iovec *sg;
 299         ssize_t ret, total = 0;
 300         unsigned int num;
 301
 302         elem = vu_queue_pop(dev, vq, sizeof(VuVirtqElement));
 303         if (!elem) {
 304             break;
 305         }
 306
 307         if (elem->in_num < 1) {
 308             fprintf(stderr, "virtio-net contains no in buffers\n");
 309             break;
 310         }
 311
 312         sg = elem->in_sg;
 313         num = elem->in_num;
 314         if (i == 0) {
 315             if (hdrlen == 12) {
 316                 mhdr_cnt = iov_copy(mhdr_sg, ARRAY_SIZE(mhdr_sg),
 317                                     sg, elem->in_num,
 318                                     offsetof(typeof(mhdr), num_buffers),
 319                                     sizeof(mhdr.num_buffers));
 320             }
 321             iov_from_buf(sg, elem->in_num, 0, &hdr, sizeof hdr);
 322             total += hdrlen;
 323             ret = iov_discard_front(&sg, &num, hdrlen);
 324             assert(ret == hdrlen);
 325         }
 326
 327         struct msghdr msg = {
 328             .msg_name = (struct sockaddr *) &vubr->backend_udp_dest,
 329             .msg_namelen = sizeof(struct sockaddr_in),
 330             .msg_iov = sg,
 331             .msg_iovlen = num,
 332             .msg_flags = MSG_DONTWAIT,
 333         };
 334         do {
 335             ret = recvmsg(vubr->backend_udp_sock, &msg, 0);
 336         } while (ret == -1 && (errno == EINTR));
 337
 338         if (i == 0) {
 339             iov_restore_front(elem->in_sg, sg, hdrlen);
 340         }
 341
 342         if (ret == -1) {
 343             if (errno == EWOULDBLOCK) {
 344                 vu_queue_rewind(dev, vq, 1);
 345                 break;
 346             }
 347
 348             vubr_die("recvmsg()");
 349         }
 350
 351         total += ret;
 352         iov_truncate(elem->in_sg, elem->in_num, total);
 353         vu_queue_fill(dev, vq, elem, total, i++);
 354
 355         free(elem);
 356         elem = NULL;
 357
 358         break;        /* could loop if DONTWAIT worked? */
 359     }
 360
 361     if (mhdr_cnt) {
 362         mhdr.num_buffers = i;
 363         iov_from_buf(mhdr_sg, mhdr_cnt,
 364                      0,
 365                      &mhdr.num_buffers, sizeof mhdr.num_buffers);
 366     }
 367
 368     vu_queue_flush(dev, vq, i);
 369     vu_queue_notify(dev, vq);
 370
 371     free(elem);
 372 }
 373
 374 static void
 375 vubr_receive_cb(int sock, void *ctx)
 376 {
 377     VubrDev *vubr = (VubrDev *)ctx;
 378
 379     if (!vu_dispatch(&vubr->vudev)) {
 380         fprintf(stderr, "Error while dispatching\n");
 381     }
 382 }
 383
 384 typedef struct WatchData {
 385     VuDev *dev;
 386     vu_watch_cb cb;
 387     void *data;
 388 } WatchData;
 389
 390 static void
 391 watch_cb(int sock, void *ctx)
 392 {
 393     struct WatchData *wd = ctx;
 394
 395     wd->cb(wd->dev, VU_WATCH_IN, wd->data);
 396 }
 397
 398 static void
 399 vubr_set_watch(VuDev *dev, int fd, int condition,
 400                vu_watch_cb cb, void *data)
 401 {
 402     VubrDev *vubr = container_of(dev, VubrDev, vudev);
 403     static WatchData watches[FD_SETSIZE];
 404     struct WatchData *wd = &watches[fd];
 405
 406     wd->cb = cb;
 407     wd->data = data;
 408     wd->dev = dev;
 409     dispatcher_add(&vubr->dispatcher, fd, wd, watch_cb);
 410 }
 411
 412 static void
 413 vubr_remove_watch(VuDev *dev, int fd)
 414 {
 415     VubrDev *vubr = container_of(dev, VubrDev, vudev);
 416
 417     dispatcher_remove(&vubr->dispatcher, fd);
 418 }
 419
 420 static int
 421 vubr_send_rarp_exec(VuDev *dev, VhostUserMsg *vmsg)
 422 {
 423     DPRINT("Function %s() not implemented yet.\n", __func__);
 424     return 0;
 425 }
 426
 427 static int
 428 vubr_process_msg(VuDev *dev, VhostUserMsg *vmsg, int *do_reply)
 429 {
 430     switch (vmsg->request) {
 431     case VHOST_USER_SEND_RARP:
 432         *do_reply = vubr_send_rarp_exec(dev, vmsg);
 433         return 1;
 434     default:
 435         /* let the library handle the rest */
 436         return 0;
 437     }
 438
 439     return 0;
 440 }
 441
 442 static void
 443 vubr_set_features(VuDev *dev, uint64_t features)
 444 {
 445     VubrDev *vubr = container_of(dev, VubrDev, vudev);
 446
 447     if ((features & (1ULL << VIRTIO_F_VERSION_1)) ||
 448         (features & (1ULL << VIRTIO_NET_F_MRG_RXBUF))) {
 449         vubr->hdrlen = 12;
 450     } else {
 451         vubr->hdrlen = 10;
 452     }
 453 }
 454
 455 static uint64_t
 456 vubr_get_features(VuDev *dev)
 457 {
 458     return 1ULL << VIRTIO_NET_F_GUEST_ANNOUNCE |
 459         1ULL << VIRTIO_NET_F_MRG_RXBUF |
 460         1ULL << VIRTIO_F_VERSION_1;
 461 }
 462
 463 static void
 464 vubr_queue_set_started(VuDev *dev, int qidx, bool started)
 465 {
 466     VubrDev *vubr = container_of(dev, VubrDev, vudev);
 467     VuVirtq *vq = vu_get_queue(dev, qidx);
 468
 469     if (started && vubr->notifier.fd >= 0) {
 470         vu_set_queue_host_notifier(dev, vq, vubr->notifier.fd,
 471                                    qemu_real_host_page_size,
 472                                    qidx * qemu_real_host_page_size);
 473     }
 474
 475     if (qidx % 2 == 1) {
 476         vu_set_queue_handler(dev, vq, started ? vubr_handle_tx : NULL);
 477     }
 478 }
 479
 480 static void
 481 vubr_panic(VuDev *dev, const char *msg)
 482 {
 483     VubrDev *vubr = container_of(dev, VubrDev, vudev);
 484
 485     fprintf(stderr, "PANIC: %s\n", msg);
 486
 487     dispatcher_remove(&vubr->dispatcher, dev->sock);
 488     vubr->quit = 1;
 489 }
 490
 491 static bool
 492 vubr_queue_is_processed_in_order(VuDev *dev, int qidx)
 493 {
 494     return true;
 495 }
 496
 497 static const VuDevIface vuiface = {
 498     .get_features = vubr_get_features,
 499     .set_features = vubr_set_features,
 500     .process_msg = vubr_process_msg,
 501     .queue_set_started = vubr_queue_set_started,
 502     .queue_is_processed_in_order = vubr_queue_is_processed_in_order,
 503 };
 504
 505 static void
 506 vubr_accept_cb(int sock, void *ctx)
 507 {
 508     VubrDev *dev = (VubrDev *)ctx;
 509     int conn_fd;
 510     struct sockaddr_un un;
 511     socklen_t len = sizeof(un);
 512
 513     conn_fd = accept(sock, (struct sockaddr *) &un, &len);
 514     if (conn_fd == -1) {
 515         vubr_die("accept()");
 516     }
 517     DPRINT("Got connection from remote peer on sock %d\n", conn_fd);
 518
 519     if (!vu_init(&dev->vudev,
 520                  VHOST_USER_BRIDGE_MAX_QUEUES,
 521                  conn_fd,
 522                  vubr_panic,
 523                  NULL,
 524                  vubr_set_watch,
 525                  vubr_remove_watch,
 526                  &vuiface)) {
 527         fprintf(stderr, "Failed to initialize libvhost-user\n");
 528         exit(1);
 529     }
 530
 531     dispatcher_add(&dev->dispatcher, conn_fd, ctx, vubr_receive_cb);
 532     dispatcher_remove(&dev->dispatcher, sock);
 533 }
 534
 535 static VubrDev *
 536 vubr_new(const char *path, bool client)
 537 {
 538     VubrDev *dev = (VubrDev *) calloc(1, sizeof(VubrDev));
 539     struct sockaddr_un un;
 540     CallbackFunc cb;
 541     size_t len;
 542
 543     /* Get a UNIX socket. */
 544     dev->sock = socket(AF_UNIX, SOCK_STREAM, 0);
 545     if (dev->sock == -1) {
 546         vubr_die("socket");
 547     }
 548
 549     dev->notifier.fd = -1;
 550
 551     un.sun_family = AF_UNIX;
 552     strcpy(un.sun_path, path);
 553     len = sizeof(un.sun_family) + strlen(path);
 554
 555     if (!client) {
 556         unlink(path);
 557
 558         if (bind(dev->sock, (struct sockaddr *) &un, len) == -1) {
 559             vubr_die("bind");
 560         }
 561
 562         if (listen(dev->sock, 1) == -1) {
 563             vubr_die("listen");
 564         }
 565         cb = vubr_accept_cb;
 566
 567         DPRINT("Waiting for connections on UNIX socket %s ...\n", path);
 568     } else {
 569         if (connect(dev->sock, (struct sockaddr *)&un, len) == -1) {
 570             vubr_die("connect");
 571         }
 572
 573         if (!vu_init(&dev->vudev,
 574                      VHOST_USER_BRIDGE_MAX_QUEUES,
 575                      dev->sock,
 576                      vubr_panic,
 577                      NULL,
 578                      vubr_set_watch,
 579                      vubr_remove_watch,
 580                      &vuiface)) {
 581             fprintf(stderr, "Failed to initialize libvhost-user\n");
 582             exit(1);
 583         }
 584
 585         cb = vubr_receive_cb;
 586     }
 587
 588     dispatcher_init(&dev->dispatcher);
 589
 590     dispatcher_add(&dev->dispatcher, dev->sock, (void *)dev, cb);
 591
 592     return dev;
 593 }
 594
 595 static void *notifier_thread(void *arg)
 596 {
 597     VuDev *dev = (VuDev *)arg;
 598     VubrDev *vubr = container_of(dev, VubrDev, vudev);
 599     int pagesize = qemu_real_host_page_size;
 600     int qidx;
 601
 602     while (true) {
 603         for (qidx = 0; qidx < VHOST_USER_BRIDGE_MAX_QUEUES; qidx++) {
 604             uint16_t *n = vubr->notifier.addr + pagesize * qidx;
 605
 606             if (*n == qidx) {
 607                 *n = 0xffff;
 608                 /* We won't miss notifications if we reset
 609                  * the memory first. */
 610                 smp_mb();
 611
 612                 DPRINT("Got a notification for queue%d via host notifier.\n",
 613                        qidx);
 614
 615                 if (qidx % 2 == 1) {
 616                     vubr_handle_tx(dev, qidx);
 617                 }
 618             }
 619             usleep(1000);
 620         }
 621     }
 622
 623     return NULL;
 624 }
 625
 626 static void
 627 vubr_host_notifier_setup(VubrDev *dev)
 628 {
 629     char template[] = "/tmp/vubr-XXXXXX";
 630     pthread_t thread;
 631     size_t length;
 632     void *addr;
 633     int fd;
 634
 635     length = qemu_real_host_page_size * VHOST_USER_BRIDGE_MAX_QUEUES;
 636
 637     fd = mkstemp(template);
 638     if (fd < 0) {
 639         vubr_die("mkstemp()");
 640     }
 641
 642     if (posix_fallocate(fd, 0, length) != 0) {
 643         vubr_die("posix_fallocate()");
 644     }
 645
 646     addr = mmap(NULL, length, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
 647     if (addr == MAP_FAILED) {
 648         vubr_die("mmap()");
 649     }
 650
 651     memset(addr, 0xff, length);
 652
 653     if (pthread_create(&thread, NULL, notifier_thread, &dev->vudev) != 0) {
 654         vubr_die("pthread_create()");
 655     }
 656
 657     dev->notifier.fd = fd;
 658     dev->notifier.addr = addr;
 659     dev->notifier.thread = thread;
 660 }
 661
 662 static void
 663 vubr_set_host(struct sockaddr_in *saddr, const char *host)
 664 {
 665     if (qemu_isdigit(host[0])) {
 666         if (!inet_aton(host, &saddr->sin_addr)) {
 667             fprintf(stderr, "inet_aton() failed.\n");
 668             exit(1);
 669         }
 670     } else {
 671         struct hostent *he = gethostbyname(host);
 672
 673         if (!he) {
 674             fprintf(stderr, "gethostbyname() failed.\n");
 675             exit(1);
 676         }
 677         saddr->sin_addr = *(struct in_addr *)he->h_addr;
 678     }
 679 }
 680
 681 static void
 682 vubr_backend_udp_setup(VubrDev *dev,
 683                        const char *local_host,
 684                        const char *local_port,
 685                        const char *remote_host,
 686                        const char *remote_port)
 687 {
 688     int sock;
 689     const char *r;
 690
 691     int lport, rport;
 692
 693     lport = strtol(local_port, (char **)&r, 0);
 694     if (r == local_port) {
 695         fprintf(stderr, "lport parsing failed.\n");
 696         exit(1);
 697     }
 698
 699     rport = strtol(remote_port, (char **)&r, 0);
 700     if (r == remote_port) {
 701         fprintf(stderr, "rport parsing failed.\n");
 702         exit(1);
 703     }
 704
 705     struct sockaddr_in si_local = {
 706         .sin_family = AF_INET,
 707         .sin_port = htons(lport),
 708     };
 709
 710     vubr_set_host(&si_local, local_host);
 711
 712     /* setup destination for sends */
 713     dev->backend_udp_dest = (struct sockaddr_in) {
 714         .sin_family = AF_INET,
 715         .sin_port = htons(rport),
 716     };
 717     vubr_set_host(&dev->backend_udp_dest, remote_host);
 718
 719     sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
 720     if (sock == -1) {
 721         vubr_die("socket");
 722     }
 723
 724     if (bind(sock, (struct sockaddr *)&si_local, sizeof(si_local)) == -1) {
 725         vubr_die("bind");
 726     }
 727
 728     dev->backend_udp_sock = sock;
 729     dispatcher_add(&dev->dispatcher, sock, dev, vubr_backend_recv_cb);
 730     DPRINT("Waiting for data from udp backend on %s:%d...\n",
 731            local_host, lport);
 732 }
 733
 734 static void
 735 vubr_run(VubrDev *dev)
 736 {
 737     while (!dev->quit) {
 738         /* timeout 200ms */
 739         dispatcher_wait(&dev->dispatcher, 200000);
 740         /* Here one can try polling strategy. */
 741     }
 742 }
 743
 744 static int
 745 vubr_parse_host_port(const char **host, const char **port, const char *buf)
 746 {
 747     char *p = strchr(buf, ':');
 748
 749     if (!p) {
 750         return -1;
 751     }
 752     *p = '\0';
 753     *host = strdup(buf);
 754     *port = strdup(p + 1);
 755     return 0;
 756 }
 757
 758 #define DEFAULT_UD_SOCKET "/tmp/vubr.sock"
 759 #define DEFAULT_LHOST "127.0.0.1"
 760 #define DEFAULT_LPORT "4444"
 761 #define DEFAULT_RHOST "127.0.0.1"
 762 #define DEFAULT_RPORT "5555"
 763
 764 static const char *ud_socket_path = DEFAULT_UD_SOCKET;
 765 static const char *lhost = DEFAULT_LHOST;
 766 static const char *lport = DEFAULT_LPORT;
 767 static const char *rhost = DEFAULT_RHOST;
 768 static const char *rport = DEFAULT_RPORT;
 769
 770 int
 771 main(int argc, char *argv[])
 772 {
 773     VubrDev *dev;
 774     int opt;
 775     bool client = false;
 776     bool host_notifier = false;
 777
 778     while ((opt = getopt(argc, argv, "l:r:u:cH")) != -1) {
 779
 780         switch (opt) {
 781         case 'l':
 782             if (vubr_parse_host_port(&lhost, &lport, optarg) < 0) {
 783                 goto out;
 784             }
 785             break;
 786         case 'r':
 787             if (vubr_parse_host_port(&rhost, &rport, optarg) < 0) {
 788                 goto out;
 789             }
 790             break;
 791         case 'u':
 792             ud_socket_path = strdup(optarg);
 793             break;
 794         case 'c':
 795             client = true;
 796             break;
 797         case 'H':
 798             host_notifier = true;
 799             break;
 800         default:
 801             goto out;
 802         }
 803     }
 804
 805     DPRINT("ud socket: %s (%s)\n", ud_socket_path,
 806            client ? "client" : "server");
 807     DPRINT("local:     %s:%s\n", lhost, lport);
 808     DPRINT("remote:    %s:%s\n", rhost, rport);
 809
 810     dev = vubr_new(ud_socket_path, client);
 811     if (!dev) {
 812         return 1;
 813     }
 814
 815     if (host_notifier) {
 816         vubr_host_notifier_setup(dev);
 817     }
 818
 819     vubr_backend_udp_setup(dev, lhost, lport, rhost, rport);
 820     vubr_run(dev);
 821
 822     vu_deinit(&dev->vudev);
 823
 824     return 0;
 825
 826 out:
 827     fprintf(stderr, "Usage: %s ", argv[0]);
 828     fprintf(stderr, "[-c] [-H] [-u ud_socket_path] [-l lhost:lport] [-r rhost:rport]\n");
 829     fprintf(stderr, "\t-u path to unix doman socket. default: %s\n",
 830             DEFAULT_UD_SOCKET);
 831     fprintf(stderr, "\t-l local host and port. default: %s:%s\n",
 832             DEFAULT_LHOST, DEFAULT_LPORT);
 833     fprintf(stderr, "\t-r remote host and port. default: %s:%s\n",
 834             DEFAULT_RHOST, DEFAULT_RPORT);
 835     fprintf(stderr, "\t-c client mode\n");
 836     fprintf(stderr, "\t-H use host notifier\n");
 837
 838     return 1;
 839 }