xref: /openbmc/qemu/tests/vhost-user-bridge.c (revision e6e03dcf)
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 "contrib/libvhost-user/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                  vubr_set_watch,
524                  vubr_remove_watch,
525                  &vuiface)) {
526         fprintf(stderr, "Failed to initialize libvhost-user\n");
527         exit(1);
528     }
529 
530     dispatcher_add(&dev->dispatcher, conn_fd, ctx, vubr_receive_cb);
531     dispatcher_remove(&dev->dispatcher, sock);
532 }
533 
534 static VubrDev *
535 vubr_new(const char *path, bool client)
536 {
537     VubrDev *dev = (VubrDev *) calloc(1, sizeof(VubrDev));
538     struct sockaddr_un un;
539     CallbackFunc cb;
540     size_t len;
541 
542     /* Get a UNIX socket. */
543     dev->sock = socket(AF_UNIX, SOCK_STREAM, 0);
544     if (dev->sock == -1) {
545         vubr_die("socket");
546     }
547 
548     dev->notifier.fd = -1;
549 
550     un.sun_family = AF_UNIX;
551     strcpy(un.sun_path, path);
552     len = sizeof(un.sun_family) + strlen(path);
553 
554     if (!client) {
555         unlink(path);
556 
557         if (bind(dev->sock, (struct sockaddr *) &un, len) == -1) {
558             vubr_die("bind");
559         }
560 
561         if (listen(dev->sock, 1) == -1) {
562             vubr_die("listen");
563         }
564         cb = vubr_accept_cb;
565 
566         DPRINT("Waiting for connections on UNIX socket %s ...\n", path);
567     } else {
568         if (connect(dev->sock, (struct sockaddr *)&un, len) == -1) {
569             vubr_die("connect");
570         }
571 
572         if (!vu_init(&dev->vudev,
573                      VHOST_USER_BRIDGE_MAX_QUEUES,
574                      dev->sock,
575                      vubr_panic,
576                      vubr_set_watch,
577                      vubr_remove_watch,
578                      &vuiface)) {
579             fprintf(stderr, "Failed to initialize libvhost-user\n");
580             exit(1);
581         }
582 
583         cb = vubr_receive_cb;
584     }
585 
586     dispatcher_init(&dev->dispatcher);
587 
588     dispatcher_add(&dev->dispatcher, dev->sock, (void *)dev, cb);
589 
590     return dev;
591 }
592 
593 static void *notifier_thread(void *arg)
594 {
595     VuDev *dev = (VuDev *)arg;
596     VubrDev *vubr = container_of(dev, VubrDev, vudev);
597     int pagesize = qemu_real_host_page_size;
598     int qidx;
599 
600     while (true) {
601         for (qidx = 0; qidx < VHOST_USER_BRIDGE_MAX_QUEUES; qidx++) {
602             uint16_t *n = vubr->notifier.addr + pagesize * qidx;
603 
604             if (*n == qidx) {
605                 *n = 0xffff;
606                 /* We won't miss notifications if we reset
607                  * the memory first. */
608                 smp_mb();
609 
610                 DPRINT("Got a notification for queue%d via host notifier.\n",
611                        qidx);
612 
613                 if (qidx % 2 == 1) {
614                     vubr_handle_tx(dev, qidx);
615                 }
616             }
617             usleep(1000);
618         }
619     }
620 
621     return NULL;
622 }
623 
624 static void
625 vubr_host_notifier_setup(VubrDev *dev)
626 {
627     char template[] = "/tmp/vubr-XXXXXX";
628     pthread_t thread;
629     size_t length;
630     void *addr;
631     int fd;
632 
633     length = qemu_real_host_page_size * VHOST_USER_BRIDGE_MAX_QUEUES;
634 
635     fd = mkstemp(template);
636     if (fd < 0) {
637         vubr_die("mkstemp()");
638     }
639 
640     if (posix_fallocate(fd, 0, length) != 0) {
641         vubr_die("posix_fallocate()");
642     }
643 
644     addr = mmap(NULL, length, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
645     if (addr == MAP_FAILED) {
646         vubr_die("mmap()");
647     }
648 
649     memset(addr, 0xff, length);
650 
651     if (pthread_create(&thread, NULL, notifier_thread, &dev->vudev) != 0) {
652         vubr_die("pthread_create()");
653     }
654 
655     dev->notifier.fd = fd;
656     dev->notifier.addr = addr;
657     dev->notifier.thread = thread;
658 }
659 
660 static void
661 vubr_set_host(struct sockaddr_in *saddr, const char *host)
662 {
663     if (qemu_isdigit(host[0])) {
664         if (!inet_aton(host, &saddr->sin_addr)) {
665             fprintf(stderr, "inet_aton() failed.\n");
666             exit(1);
667         }
668     } else {
669         struct hostent *he = gethostbyname(host);
670 
671         if (!he) {
672             fprintf(stderr, "gethostbyname() failed.\n");
673             exit(1);
674         }
675         saddr->sin_addr = *(struct in_addr *)he->h_addr;
676     }
677 }
678 
679 static void
680 vubr_backend_udp_setup(VubrDev *dev,
681                        const char *local_host,
682                        const char *local_port,
683                        const char *remote_host,
684                        const char *remote_port)
685 {
686     int sock;
687     const char *r;
688 
689     int lport, rport;
690 
691     lport = strtol(local_port, (char **)&r, 0);
692     if (r == local_port) {
693         fprintf(stderr, "lport parsing failed.\n");
694         exit(1);
695     }
696 
697     rport = strtol(remote_port, (char **)&r, 0);
698     if (r == remote_port) {
699         fprintf(stderr, "rport parsing failed.\n");
700         exit(1);
701     }
702 
703     struct sockaddr_in si_local = {
704         .sin_family = AF_INET,
705         .sin_port = htons(lport),
706     };
707 
708     vubr_set_host(&si_local, local_host);
709 
710     /* setup destination for sends */
711     dev->backend_udp_dest = (struct sockaddr_in) {
712         .sin_family = AF_INET,
713         .sin_port = htons(rport),
714     };
715     vubr_set_host(&dev->backend_udp_dest, remote_host);
716 
717     sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
718     if (sock == -1) {
719         vubr_die("socket");
720     }
721 
722     if (bind(sock, (struct sockaddr *)&si_local, sizeof(si_local)) == -1) {
723         vubr_die("bind");
724     }
725 
726     dev->backend_udp_sock = sock;
727     dispatcher_add(&dev->dispatcher, sock, dev, vubr_backend_recv_cb);
728     DPRINT("Waiting for data from udp backend on %s:%d...\n",
729            local_host, lport);
730 }
731 
732 static void
733 vubr_run(VubrDev *dev)
734 {
735     while (!dev->quit) {
736         /* timeout 200ms */
737         dispatcher_wait(&dev->dispatcher, 200000);
738         /* Here one can try polling strategy. */
739     }
740 }
741 
742 static int
743 vubr_parse_host_port(const char **host, const char **port, const char *buf)
744 {
745     char *p = strchr(buf, ':');
746 
747     if (!p) {
748         return -1;
749     }
750     *p = '\0';
751     *host = strdup(buf);
752     *port = strdup(p + 1);
753     return 0;
754 }
755 
756 #define DEFAULT_UD_SOCKET "/tmp/vubr.sock"
757 #define DEFAULT_LHOST "127.0.0.1"
758 #define DEFAULT_LPORT "4444"
759 #define DEFAULT_RHOST "127.0.0.1"
760 #define DEFAULT_RPORT "5555"
761 
762 static const char *ud_socket_path = DEFAULT_UD_SOCKET;
763 static const char *lhost = DEFAULT_LHOST;
764 static const char *lport = DEFAULT_LPORT;
765 static const char *rhost = DEFAULT_RHOST;
766 static const char *rport = DEFAULT_RPORT;
767 
768 int
769 main(int argc, char *argv[])
770 {
771     VubrDev *dev;
772     int opt;
773     bool client = false;
774     bool host_notifier = false;
775 
776     while ((opt = getopt(argc, argv, "l:r:u:cH")) != -1) {
777 
778         switch (opt) {
779         case 'l':
780             if (vubr_parse_host_port(&lhost, &lport, optarg) < 0) {
781                 goto out;
782             }
783             break;
784         case 'r':
785             if (vubr_parse_host_port(&rhost, &rport, optarg) < 0) {
786                 goto out;
787             }
788             break;
789         case 'u':
790             ud_socket_path = strdup(optarg);
791             break;
792         case 'c':
793             client = true;
794             break;
795         case 'H':
796             host_notifier = true;
797             break;
798         default:
799             goto out;
800         }
801     }
802 
803     DPRINT("ud socket: %s (%s)\n", ud_socket_path,
804            client ? "client" : "server");
805     DPRINT("local:     %s:%s\n", lhost, lport);
806     DPRINT("remote:    %s:%s\n", rhost, rport);
807 
808     dev = vubr_new(ud_socket_path, client);
809     if (!dev) {
810         return 1;
811     }
812 
813     if (host_notifier) {
814         vubr_host_notifier_setup(dev);
815     }
816 
817     vubr_backend_udp_setup(dev, lhost, lport, rhost, rport);
818     vubr_run(dev);
819 
820     vu_deinit(&dev->vudev);
821 
822     return 0;
823 
824 out:
825     fprintf(stderr, "Usage: %s ", argv[0]);
826     fprintf(stderr, "[-c] [-H] [-u ud_socket_path] [-l lhost:lport] [-r rhost:rport]\n");
827     fprintf(stderr, "\t-u path to unix doman socket. default: %s\n",
828             DEFAULT_UD_SOCKET);
829     fprintf(stderr, "\t-l local host and port. default: %s:%s\n",
830             DEFAULT_LHOST, DEFAULT_LPORT);
831     fprintf(stderr, "\t-r remote host and port. default: %s:%s\n",
832             DEFAULT_RHOST, DEFAULT_RPORT);
833     fprintf(stderr, "\t-c client mode\n");
834     fprintf(stderr, "\t-H use host notifier\n");
835 
836     return 1;
837 }
838