xref: /openbmc/qemu/tests/vhost-user-bridge.c (revision 9543fdaf)
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/atomic.h"
33 #include "qemu/osdep.h"
34 #include "qemu/iov.h"
35 #include "standard-headers/linux/virtio_net.h"
36 #include "contrib/libvhost-user/libvhost-user.h"
37 
38 #define VHOST_USER_BRIDGE_DEBUG 1
39 
40 #define DPRINT(...) \
41     do { \
42         if (VHOST_USER_BRIDGE_DEBUG) { \
43             printf(__VA_ARGS__); \
44         } \
45     } while (0)
46 
47 typedef void (*CallbackFunc)(int sock, void *ctx);
48 
49 typedef struct Event {
50     void *ctx;
51     CallbackFunc callback;
52 } Event;
53 
54 typedef struct Dispatcher {
55     int max_sock;
56     fd_set fdset;
57     Event events[FD_SETSIZE];
58 } Dispatcher;
59 
60 typedef struct VubrDev {
61     VuDev vudev;
62     Dispatcher dispatcher;
63     int backend_udp_sock;
64     struct sockaddr_in backend_udp_dest;
65     int hdrlen;
66     int sock;
67     int ready;
68     int quit;
69     struct {
70         int fd;
71         void *addr;
72         pthread_t thread;
73     } notifier;
74 } VubrDev;
75 
76 static void
77 vubr_die(const char *s)
78 {
79     perror(s);
80     exit(1);
81 }
82 
83 static int
84 dispatcher_init(Dispatcher *dispr)
85 {
86     FD_ZERO(&dispr->fdset);
87     dispr->max_sock = -1;
88     return 0;
89 }
90 
91 static int
92 dispatcher_add(Dispatcher *dispr, int sock, void *ctx, CallbackFunc cb)
93 {
94     if (sock >= FD_SETSIZE) {
95         fprintf(stderr,
96                 "Error: Failed to add new event. sock %d should be less than %d\n",
97                 sock, FD_SETSIZE);
98         return -1;
99     }
100 
101     dispr->events[sock].ctx = ctx;
102     dispr->events[sock].callback = cb;
103 
104     FD_SET(sock, &dispr->fdset);
105     if (sock > dispr->max_sock) {
106         dispr->max_sock = sock;
107     }
108     DPRINT("Added sock %d for watching. max_sock: %d\n",
109            sock, dispr->max_sock);
110     return 0;
111 }
112 
113 static int
114 dispatcher_remove(Dispatcher *dispr, int sock)
115 {
116     if (sock >= FD_SETSIZE) {
117         fprintf(stderr,
118                 "Error: Failed to remove event. sock %d should be less than %d\n",
119                 sock, FD_SETSIZE);
120         return -1;
121     }
122 
123     FD_CLR(sock, &dispr->fdset);
124     DPRINT("Sock %d removed from dispatcher watch.\n", sock);
125     return 0;
126 }
127 
128 /* timeout in us */
129 static int
130 dispatcher_wait(Dispatcher *dispr, uint32_t timeout)
131 {
132     struct timeval tv;
133     tv.tv_sec = timeout / 1000000;
134     tv.tv_usec = timeout % 1000000;
135 
136     fd_set fdset = dispr->fdset;
137 
138     /* wait until some of sockets become readable. */
139     int rc = select(dispr->max_sock + 1, &fdset, 0, 0, &tv);
140 
141     if (rc == -1) {
142         vubr_die("select");
143     }
144 
145     /* Timeout */
146     if (rc == 0) {
147         return 0;
148     }
149 
150     /* Now call callback for every ready socket. */
151 
152     int sock;
153     for (sock = 0; sock < dispr->max_sock + 1; sock++) {
154         /* The callback on a socket can remove other sockets from the
155          * dispatcher, thus we have to check that the socket is
156          * still not removed from dispatcher's list
157          */
158         if (FD_ISSET(sock, &fdset) && FD_ISSET(sock, &dispr->fdset)) {
159             Event *e = &dispr->events[sock];
160             e->callback(sock, e->ctx);
161         }
162     }
163 
164     return 0;
165 }
166 
167 static void
168 vubr_handle_tx(VuDev *dev, int qidx)
169 {
170     VuVirtq *vq = vu_get_queue(dev, qidx);
171     VubrDev *vubr = container_of(dev, VubrDev, vudev);
172     int hdrlen = vubr->hdrlen;
173     VuVirtqElement *elem = NULL;
174 
175     assert(qidx % 2);
176 
177     for (;;) {
178         ssize_t ret;
179         unsigned int out_num;
180         struct iovec sg[VIRTQUEUE_MAX_SIZE], *out_sg;
181 
182         elem = vu_queue_pop(dev, vq, sizeof(VuVirtqElement));
183         if (!elem) {
184             break;
185         }
186 
187         out_num = elem->out_num;
188         out_sg = elem->out_sg;
189         if (out_num < 1) {
190             fprintf(stderr, "virtio-net header not in first element\n");
191             break;
192         }
193         if (VHOST_USER_BRIDGE_DEBUG) {
194             iov_hexdump(out_sg, out_num, stderr, "TX:", 1024);
195         }
196 
197         if (hdrlen) {
198             unsigned sg_num = iov_copy(sg, ARRAY_SIZE(sg),
199                                        out_sg, out_num,
200                                        hdrlen, -1);
201             out_num = sg_num;
202             out_sg = sg;
203         }
204 
205         struct msghdr msg = {
206             .msg_name = (struct sockaddr *) &vubr->backend_udp_dest,
207             .msg_namelen = sizeof(struct sockaddr_in),
208             .msg_iov = out_sg,
209             .msg_iovlen = out_num,
210         };
211         do {
212             ret = sendmsg(vubr->backend_udp_sock, &msg, 0);
213         } while (ret == -1 && (errno == EAGAIN || errno == EINTR));
214 
215         if (ret == -1) {
216             vubr_die("sendmsg()");
217         }
218 
219         vu_queue_push(dev, vq, elem, 0);
220         vu_queue_notify(dev, vq);
221 
222         free(elem);
223         elem = NULL;
224     }
225 
226     free(elem);
227 }
228 
229 
230 /* this function reverse the effect of iov_discard_front() it must be
231  * called with 'front' being the original struct iovec and 'bytes'
232  * being the number of bytes you shaved off
233  */
234 static void
235 iov_restore_front(struct iovec *front, struct iovec *iov, size_t bytes)
236 {
237     struct iovec *cur;
238 
239     for (cur = front; cur != iov; cur++) {
240         assert(bytes >= cur->iov_len);
241         bytes -= cur->iov_len;
242     }
243 
244     cur->iov_base -= bytes;
245     cur->iov_len += bytes;
246 }
247 
248 static void
249 iov_truncate(struct iovec *iov, unsigned iovc, size_t bytes)
250 {
251     unsigned i;
252 
253     for (i = 0; i < iovc; i++, iov++) {
254         if (bytes < iov->iov_len) {
255             iov->iov_len = bytes;
256             return;
257         }
258 
259         bytes -= iov->iov_len;
260     }
261 
262     assert(!"couldn't truncate iov");
263 }
264 
265 static void
266 vubr_backend_recv_cb(int sock, void *ctx)
267 {
268     VubrDev *vubr = (VubrDev *) ctx;
269     VuDev *dev = &vubr->vudev;
270     VuVirtq *vq = vu_get_queue(dev, 0);
271     VuVirtqElement *elem = NULL;
272     struct iovec mhdr_sg[VIRTQUEUE_MAX_SIZE];
273     struct virtio_net_hdr_mrg_rxbuf mhdr;
274     unsigned mhdr_cnt = 0;
275     int hdrlen = vubr->hdrlen;
276     int i = 0;
277     struct virtio_net_hdr hdr = {
278         .flags = 0,
279         .gso_type = VIRTIO_NET_HDR_GSO_NONE
280     };
281 
282     DPRINT("\n\n   ***   IN UDP RECEIVE CALLBACK    ***\n\n");
283     DPRINT("    hdrlen = %d\n", hdrlen);
284 
285     if (!vu_queue_enabled(dev, vq) ||
286         !vu_queue_started(dev, vq) ||
287         !vu_queue_avail_bytes(dev, vq, hdrlen, 0)) {
288         DPRINT("Got UDP packet, but no available descriptors on RX virtq.\n");
289         return;
290     }
291 
292     while (1) {
293         struct iovec *sg;
294         ssize_t ret, total = 0;
295         unsigned int num;
296 
297         elem = vu_queue_pop(dev, vq, sizeof(VuVirtqElement));
298         if (!elem) {
299             break;
300         }
301 
302         if (elem->in_num < 1) {
303             fprintf(stderr, "virtio-net contains no in buffers\n");
304             break;
305         }
306 
307         sg = elem->in_sg;
308         num = elem->in_num;
309         if (i == 0) {
310             if (hdrlen == 12) {
311                 mhdr_cnt = iov_copy(mhdr_sg, ARRAY_SIZE(mhdr_sg),
312                                     sg, elem->in_num,
313                                     offsetof(typeof(mhdr), num_buffers),
314                                     sizeof(mhdr.num_buffers));
315             }
316             iov_from_buf(sg, elem->in_num, 0, &hdr, sizeof hdr);
317             total += hdrlen;
318             ret = iov_discard_front(&sg, &num, hdrlen);
319             assert(ret == hdrlen);
320         }
321 
322         struct msghdr msg = {
323             .msg_name = (struct sockaddr *) &vubr->backend_udp_dest,
324             .msg_namelen = sizeof(struct sockaddr_in),
325             .msg_iov = sg,
326             .msg_iovlen = num,
327             .msg_flags = MSG_DONTWAIT,
328         };
329         do {
330             ret = recvmsg(vubr->backend_udp_sock, &msg, 0);
331         } while (ret == -1 && (errno == EINTR));
332 
333         if (i == 0) {
334             iov_restore_front(elem->in_sg, sg, hdrlen);
335         }
336 
337         if (ret == -1) {
338             if (errno == EWOULDBLOCK) {
339                 vu_queue_rewind(dev, vq, 1);
340                 break;
341             }
342 
343             vubr_die("recvmsg()");
344         }
345 
346         total += ret;
347         iov_truncate(elem->in_sg, elem->in_num, total);
348         vu_queue_fill(dev, vq, elem, total, i++);
349 
350         free(elem);
351         elem = NULL;
352 
353         break;        /* could loop if DONTWAIT worked? */
354     }
355 
356     if (mhdr_cnt) {
357         mhdr.num_buffers = i;
358         iov_from_buf(mhdr_sg, mhdr_cnt,
359                      0,
360                      &mhdr.num_buffers, sizeof mhdr.num_buffers);
361     }
362 
363     vu_queue_flush(dev, vq, i);
364     vu_queue_notify(dev, vq);
365 
366     free(elem);
367 }
368 
369 static void
370 vubr_receive_cb(int sock, void *ctx)
371 {
372     VubrDev *vubr = (VubrDev *)ctx;
373 
374     if (!vu_dispatch(&vubr->vudev)) {
375         fprintf(stderr, "Error while dispatching\n");
376     }
377 }
378 
379 typedef struct WatchData {
380     VuDev *dev;
381     vu_watch_cb cb;
382     void *data;
383 } WatchData;
384 
385 static void
386 watch_cb(int sock, void *ctx)
387 {
388     struct WatchData *wd = ctx;
389 
390     wd->cb(wd->dev, VU_WATCH_IN, wd->data);
391 }
392 
393 static void
394 vubr_set_watch(VuDev *dev, int fd, int condition,
395                vu_watch_cb cb, void *data)
396 {
397     VubrDev *vubr = container_of(dev, VubrDev, vudev);
398     static WatchData watches[FD_SETSIZE];
399     struct WatchData *wd = &watches[fd];
400 
401     wd->cb = cb;
402     wd->data = data;
403     wd->dev = dev;
404     dispatcher_add(&vubr->dispatcher, fd, wd, watch_cb);
405 }
406 
407 static void
408 vubr_remove_watch(VuDev *dev, int fd)
409 {
410     VubrDev *vubr = container_of(dev, VubrDev, vudev);
411 
412     dispatcher_remove(&vubr->dispatcher, fd);
413 }
414 
415 static int
416 vubr_send_rarp_exec(VuDev *dev, VhostUserMsg *vmsg)
417 {
418     DPRINT("Function %s() not implemented yet.\n", __func__);
419     return 0;
420 }
421 
422 static int
423 vubr_process_msg(VuDev *dev, VhostUserMsg *vmsg, int *do_reply)
424 {
425     switch (vmsg->request) {
426     case VHOST_USER_SEND_RARP:
427         *do_reply = vubr_send_rarp_exec(dev, vmsg);
428         return 1;
429     default:
430         /* let the library handle the rest */
431         return 0;
432     }
433 
434     return 0;
435 }
436 
437 static void
438 vubr_set_features(VuDev *dev, uint64_t features)
439 {
440     VubrDev *vubr = container_of(dev, VubrDev, vudev);
441 
442     if ((features & (1ULL << VIRTIO_F_VERSION_1)) ||
443         (features & (1ULL << VIRTIO_NET_F_MRG_RXBUF))) {
444         vubr->hdrlen = 12;
445     } else {
446         vubr->hdrlen = 10;
447     }
448 }
449 
450 static uint64_t
451 vubr_get_features(VuDev *dev)
452 {
453     return 1ULL << VIRTIO_NET_F_GUEST_ANNOUNCE |
454         1ULL << VIRTIO_NET_F_MRG_RXBUF |
455         1ULL << VIRTIO_F_VERSION_1;
456 }
457 
458 static void
459 vubr_queue_set_started(VuDev *dev, int qidx, bool started)
460 {
461     VubrDev *vubr = container_of(dev, VubrDev, vudev);
462     VuVirtq *vq = vu_get_queue(dev, qidx);
463 
464     if (started && vubr->notifier.fd >= 0) {
465         vu_set_queue_host_notifier(dev, vq, vubr->notifier.fd,
466                                    getpagesize(),
467                                    qidx * getpagesize());
468     }
469 
470     if (qidx % 2 == 1) {
471         vu_set_queue_handler(dev, vq, started ? vubr_handle_tx : NULL);
472     }
473 }
474 
475 static void
476 vubr_panic(VuDev *dev, const char *msg)
477 {
478     VubrDev *vubr = container_of(dev, VubrDev, vudev);
479 
480     fprintf(stderr, "PANIC: %s\n", msg);
481 
482     dispatcher_remove(&vubr->dispatcher, dev->sock);
483     vubr->quit = 1;
484 }
485 
486 static bool
487 vubr_queue_is_processed_in_order(VuDev *dev, int qidx)
488 {
489     return true;
490 }
491 
492 static const VuDevIface vuiface = {
493     .get_features = vubr_get_features,
494     .set_features = vubr_set_features,
495     .process_msg = vubr_process_msg,
496     .queue_set_started = vubr_queue_set_started,
497     .queue_is_processed_in_order = vubr_queue_is_processed_in_order,
498 };
499 
500 static void
501 vubr_accept_cb(int sock, void *ctx)
502 {
503     VubrDev *dev = (VubrDev *)ctx;
504     int conn_fd;
505     struct sockaddr_un un;
506     socklen_t len = sizeof(un);
507 
508     conn_fd = accept(sock, (struct sockaddr *) &un, &len);
509     if (conn_fd == -1) {
510         vubr_die("accept()");
511     }
512     DPRINT("Got connection from remote peer on sock %d\n", conn_fd);
513 
514     vu_init(&dev->vudev,
515             conn_fd,
516             vubr_panic,
517             vubr_set_watch,
518             vubr_remove_watch,
519             &vuiface);
520 
521     dispatcher_add(&dev->dispatcher, conn_fd, ctx, vubr_receive_cb);
522     dispatcher_remove(&dev->dispatcher, sock);
523 }
524 
525 static VubrDev *
526 vubr_new(const char *path, bool client)
527 {
528     VubrDev *dev = (VubrDev *) calloc(1, sizeof(VubrDev));
529     struct sockaddr_un un;
530     CallbackFunc cb;
531     size_t len;
532 
533     /* Get a UNIX socket. */
534     dev->sock = socket(AF_UNIX, SOCK_STREAM, 0);
535     if (dev->sock == -1) {
536         vubr_die("socket");
537     }
538 
539     dev->notifier.fd = -1;
540 
541     un.sun_family = AF_UNIX;
542     strcpy(un.sun_path, path);
543     len = sizeof(un.sun_family) + strlen(path);
544 
545     if (!client) {
546         unlink(path);
547 
548         if (bind(dev->sock, (struct sockaddr *) &un, len) == -1) {
549             vubr_die("bind");
550         }
551 
552         if (listen(dev->sock, 1) == -1) {
553             vubr_die("listen");
554         }
555         cb = vubr_accept_cb;
556 
557         DPRINT("Waiting for connections on UNIX socket %s ...\n", path);
558     } else {
559         if (connect(dev->sock, (struct sockaddr *)&un, len) == -1) {
560             vubr_die("connect");
561         }
562         vu_init(&dev->vudev,
563                 dev->sock,
564                 vubr_panic,
565                 vubr_set_watch,
566                 vubr_remove_watch,
567                 &vuiface);
568         cb = vubr_receive_cb;
569     }
570 
571     dispatcher_init(&dev->dispatcher);
572 
573     dispatcher_add(&dev->dispatcher, dev->sock, (void *)dev, cb);
574 
575     return dev;
576 }
577 
578 static void *notifier_thread(void *arg)
579 {
580     VuDev *dev = (VuDev *)arg;
581     VubrDev *vubr = container_of(dev, VubrDev, vudev);
582     int pagesize = getpagesize();
583     int qidx;
584 
585     while (true) {
586         for (qidx = 0; qidx < VHOST_MAX_NR_VIRTQUEUE; qidx++) {
587             uint16_t *n = vubr->notifier.addr + pagesize * qidx;
588 
589             if (*n == qidx) {
590                 *n = 0xffff;
591                 /* We won't miss notifications if we reset
592                  * the memory first. */
593                 smp_mb();
594 
595                 DPRINT("Got a notification for queue%d via host notifier.\n",
596                        qidx);
597 
598                 if (qidx % 2 == 1) {
599                     vubr_handle_tx(dev, qidx);
600                 }
601             }
602             usleep(1000);
603         }
604     }
605 
606     return NULL;
607 }
608 
609 static void
610 vubr_host_notifier_setup(VubrDev *dev)
611 {
612     char template[] = "/tmp/vubr-XXXXXX";
613     pthread_t thread;
614     size_t length;
615     void *addr;
616     int fd;
617 
618     length = getpagesize() * VHOST_MAX_NR_VIRTQUEUE;
619 
620     fd = mkstemp(template);
621     if (fd < 0) {
622         vubr_die("mkstemp()");
623     }
624 
625     if (posix_fallocate(fd, 0, length) != 0) {
626         vubr_die("posix_fallocate()");
627     }
628 
629     addr = mmap(NULL, length, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
630     if (addr == MAP_FAILED) {
631         vubr_die("mmap()");
632     }
633 
634     memset(addr, 0xff, length);
635 
636     if (pthread_create(&thread, NULL, notifier_thread, &dev->vudev) != 0) {
637         vubr_die("pthread_create()");
638     }
639 
640     dev->notifier.fd = fd;
641     dev->notifier.addr = addr;
642     dev->notifier.thread = thread;
643 }
644 
645 static void
646 vubr_set_host(struct sockaddr_in *saddr, const char *host)
647 {
648     if (isdigit(host[0])) {
649         if (!inet_aton(host, &saddr->sin_addr)) {
650             fprintf(stderr, "inet_aton() failed.\n");
651             exit(1);
652         }
653     } else {
654         struct hostent *he = gethostbyname(host);
655 
656         if (!he) {
657             fprintf(stderr, "gethostbyname() failed.\n");
658             exit(1);
659         }
660         saddr->sin_addr = *(struct in_addr *)he->h_addr;
661     }
662 }
663 
664 static void
665 vubr_backend_udp_setup(VubrDev *dev,
666                        const char *local_host,
667                        const char *local_port,
668                        const char *remote_host,
669                        const char *remote_port)
670 {
671     int sock;
672     const char *r;
673 
674     int lport, rport;
675 
676     lport = strtol(local_port, (char **)&r, 0);
677     if (r == local_port) {
678         fprintf(stderr, "lport parsing failed.\n");
679         exit(1);
680     }
681 
682     rport = strtol(remote_port, (char **)&r, 0);
683     if (r == remote_port) {
684         fprintf(stderr, "rport parsing failed.\n");
685         exit(1);
686     }
687 
688     struct sockaddr_in si_local = {
689         .sin_family = AF_INET,
690         .sin_port = htons(lport),
691     };
692 
693     vubr_set_host(&si_local, local_host);
694 
695     /* setup destination for sends */
696     dev->backend_udp_dest = (struct sockaddr_in) {
697         .sin_family = AF_INET,
698         .sin_port = htons(rport),
699     };
700     vubr_set_host(&dev->backend_udp_dest, remote_host);
701 
702     sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
703     if (sock == -1) {
704         vubr_die("socket");
705     }
706 
707     if (bind(sock, (struct sockaddr *)&si_local, sizeof(si_local)) == -1) {
708         vubr_die("bind");
709     }
710 
711     dev->backend_udp_sock = sock;
712     dispatcher_add(&dev->dispatcher, sock, dev, vubr_backend_recv_cb);
713     DPRINT("Waiting for data from udp backend on %s:%d...\n",
714            local_host, lport);
715 }
716 
717 static void
718 vubr_run(VubrDev *dev)
719 {
720     while (!dev->quit) {
721         /* timeout 200ms */
722         dispatcher_wait(&dev->dispatcher, 200000);
723         /* Here one can try polling strategy. */
724     }
725 }
726 
727 static int
728 vubr_parse_host_port(const char **host, const char **port, const char *buf)
729 {
730     char *p = strchr(buf, ':');
731 
732     if (!p) {
733         return -1;
734     }
735     *p = '\0';
736     *host = strdup(buf);
737     *port = strdup(p + 1);
738     return 0;
739 }
740 
741 #define DEFAULT_UD_SOCKET "/tmp/vubr.sock"
742 #define DEFAULT_LHOST "127.0.0.1"
743 #define DEFAULT_LPORT "4444"
744 #define DEFAULT_RHOST "127.0.0.1"
745 #define DEFAULT_RPORT "5555"
746 
747 static const char *ud_socket_path = DEFAULT_UD_SOCKET;
748 static const char *lhost = DEFAULT_LHOST;
749 static const char *lport = DEFAULT_LPORT;
750 static const char *rhost = DEFAULT_RHOST;
751 static const char *rport = DEFAULT_RPORT;
752 
753 int
754 main(int argc, char *argv[])
755 {
756     VubrDev *dev;
757     int opt;
758     bool client = false;
759     bool host_notifier = false;
760 
761     while ((opt = getopt(argc, argv, "l:r:u:cH")) != -1) {
762 
763         switch (opt) {
764         case 'l':
765             if (vubr_parse_host_port(&lhost, &lport, optarg) < 0) {
766                 goto out;
767             }
768             break;
769         case 'r':
770             if (vubr_parse_host_port(&rhost, &rport, optarg) < 0) {
771                 goto out;
772             }
773             break;
774         case 'u':
775             ud_socket_path = strdup(optarg);
776             break;
777         case 'c':
778             client = true;
779             break;
780         case 'H':
781             host_notifier = true;
782             break;
783         default:
784             goto out;
785         }
786     }
787 
788     DPRINT("ud socket: %s (%s)\n", ud_socket_path,
789            client ? "client" : "server");
790     DPRINT("local:     %s:%s\n", lhost, lport);
791     DPRINT("remote:    %s:%s\n", rhost, rport);
792 
793     dev = vubr_new(ud_socket_path, client);
794     if (!dev) {
795         return 1;
796     }
797 
798     if (host_notifier) {
799         vubr_host_notifier_setup(dev);
800     }
801 
802     vubr_backend_udp_setup(dev, lhost, lport, rhost, rport);
803     vubr_run(dev);
804 
805     vu_deinit(&dev->vudev);
806 
807     return 0;
808 
809 out:
810     fprintf(stderr, "Usage: %s ", argv[0]);
811     fprintf(stderr, "[-c] [-H] [-u ud_socket_path] [-l lhost:lport] [-r rhost:rport]\n");
812     fprintf(stderr, "\t-u path to unix doman socket. default: %s\n",
813             DEFAULT_UD_SOCKET);
814     fprintf(stderr, "\t-l local host and port. default: %s:%s\n",
815             DEFAULT_LHOST, DEFAULT_LPORT);
816     fprintf(stderr, "\t-r remote host and port. default: %s:%s\n",
817             DEFAULT_RHOST, DEFAULT_RPORT);
818     fprintf(stderr, "\t-c client mode\n");
819     fprintf(stderr, "\t-H use host notifier\n");
820 
821     return 1;
822 }
823