xref: /openbmc/qemu/tests/vhost-user-bridge.c (revision f4152040)
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         ret = RETRY_ON_EINTR(recvmsg(vubr->backend_udp_sock, &msg, 0));
335 
336         if (i == 0) {
337             iov_restore_front(elem->in_sg, sg, hdrlen);
338         }
339 
340         if (ret == -1) {
341             if (errno == EWOULDBLOCK) {
342                 vu_queue_rewind(dev, vq, 1);
343                 break;
344             }
345 
346             vubr_die("recvmsg()");
347         }
348 
349         total += ret;
350         iov_truncate(elem->in_sg, elem->in_num, total);
351         vu_queue_fill(dev, vq, elem, total, i++);
352 
353         free(elem);
354         elem = NULL;
355 
356         break;        /* could loop if DONTWAIT worked? */
357     }
358 
359     if (mhdr_cnt) {
360         mhdr.num_buffers = i;
361         iov_from_buf(mhdr_sg, mhdr_cnt,
362                      0,
363                      &mhdr.num_buffers, sizeof mhdr.num_buffers);
364     }
365 
366     vu_queue_flush(dev, vq, i);
367     vu_queue_notify(dev, vq);
368 
369     free(elem);
370 }
371 
372 static void
373 vubr_receive_cb(int sock, void *ctx)
374 {
375     VubrDev *vubr = (VubrDev *)ctx;
376 
377     if (!vu_dispatch(&vubr->vudev)) {
378         fprintf(stderr, "Error while dispatching\n");
379     }
380 }
381 
382 typedef struct WatchData {
383     VuDev *dev;
384     vu_watch_cb cb;
385     void *data;
386 } WatchData;
387 
388 static void
389 watch_cb(int sock, void *ctx)
390 {
391     struct WatchData *wd = ctx;
392 
393     wd->cb(wd->dev, VU_WATCH_IN, wd->data);
394 }
395 
396 static void
397 vubr_set_watch(VuDev *dev, int fd, int condition,
398                vu_watch_cb cb, void *data)
399 {
400     VubrDev *vubr = container_of(dev, VubrDev, vudev);
401     static WatchData watches[FD_SETSIZE];
402     struct WatchData *wd = &watches[fd];
403 
404     wd->cb = cb;
405     wd->data = data;
406     wd->dev = dev;
407     dispatcher_add(&vubr->dispatcher, fd, wd, watch_cb);
408 }
409 
410 static void
411 vubr_remove_watch(VuDev *dev, int fd)
412 {
413     VubrDev *vubr = container_of(dev, VubrDev, vudev);
414 
415     dispatcher_remove(&vubr->dispatcher, fd);
416 }
417 
418 static int
419 vubr_send_rarp_exec(VuDev *dev, VhostUserMsg *vmsg)
420 {
421     DPRINT("Function %s() not implemented yet.\n", __func__);
422     return 0;
423 }
424 
425 static int
426 vubr_process_msg(VuDev *dev, VhostUserMsg *vmsg, int *do_reply)
427 {
428     switch (vmsg->request) {
429     case VHOST_USER_SEND_RARP:
430         *do_reply = vubr_send_rarp_exec(dev, vmsg);
431         return 1;
432     default:
433         /* let the library handle the rest */
434         return 0;
435     }
436 
437     return 0;
438 }
439 
440 static void
441 vubr_set_features(VuDev *dev, uint64_t features)
442 {
443     VubrDev *vubr = container_of(dev, VubrDev, vudev);
444 
445     if ((features & (1ULL << VIRTIO_F_VERSION_1)) ||
446         (features & (1ULL << VIRTIO_NET_F_MRG_RXBUF))) {
447         vubr->hdrlen = 12;
448     } else {
449         vubr->hdrlen = 10;
450     }
451 }
452 
453 static uint64_t
454 vubr_get_features(VuDev *dev)
455 {
456     return 1ULL << VIRTIO_NET_F_GUEST_ANNOUNCE |
457         1ULL << VIRTIO_NET_F_MRG_RXBUF |
458         1ULL << VIRTIO_F_VERSION_1;
459 }
460 
461 static void
462 vubr_queue_set_started(VuDev *dev, int qidx, bool started)
463 {
464     VubrDev *vubr = container_of(dev, VubrDev, vudev);
465     VuVirtq *vq = vu_get_queue(dev, qidx);
466 
467     if (started && vubr->notifier.fd >= 0) {
468         vu_set_queue_host_notifier(dev, vq, vubr->notifier.fd,
469                                    qemu_real_host_page_size(),
470                                    qidx * qemu_real_host_page_size());
471     }
472 
473     if (qidx % 2 == 1) {
474         vu_set_queue_handler(dev, vq, started ? vubr_handle_tx : NULL);
475     }
476 }
477 
478 static void
479 vubr_panic(VuDev *dev, const char *msg)
480 {
481     VubrDev *vubr = container_of(dev, VubrDev, vudev);
482 
483     fprintf(stderr, "PANIC: %s\n", msg);
484 
485     dispatcher_remove(&vubr->dispatcher, dev->sock);
486     vubr->quit = 1;
487 }
488 
489 static bool
490 vubr_queue_is_processed_in_order(VuDev *dev, int qidx)
491 {
492     return true;
493 }
494 
495 static const VuDevIface vuiface = {
496     .get_features = vubr_get_features,
497     .set_features = vubr_set_features,
498     .process_msg = vubr_process_msg,
499     .queue_set_started = vubr_queue_set_started,
500     .queue_is_processed_in_order = vubr_queue_is_processed_in_order,
501 };
502 
503 static void
504 vubr_accept_cb(int sock, void *ctx)
505 {
506     VubrDev *dev = (VubrDev *)ctx;
507     int conn_fd;
508     struct sockaddr_un un;
509     socklen_t len = sizeof(un);
510 
511     conn_fd = accept(sock, (struct sockaddr *) &un, &len);
512     if (conn_fd == -1) {
513         vubr_die("accept()");
514     }
515     DPRINT("Got connection from remote peer on sock %d\n", conn_fd);
516 
517     if (!vu_init(&dev->vudev,
518                  VHOST_USER_BRIDGE_MAX_QUEUES,
519                  conn_fd,
520                  vubr_panic,
521                  NULL,
522                  vubr_set_watch,
523                  vubr_remove_watch,
524                  &vuiface)) {
525         fprintf(stderr, "Failed to initialize libvhost-user\n");
526         exit(1);
527     }
528 
529     dispatcher_add(&dev->dispatcher, conn_fd, ctx, vubr_receive_cb);
530     dispatcher_remove(&dev->dispatcher, sock);
531 }
532 
533 static VubrDev *
534 vubr_new(const char *path, bool client)
535 {
536     VubrDev *dev = (VubrDev *) calloc(1, sizeof(VubrDev));
537     struct sockaddr_un un;
538     CallbackFunc cb;
539     size_t len;
540 
541     if (strlen(path) >= sizeof(un.sun_path)) {
542         fprintf(stderr, "unix domain socket path '%s' is too long\n", path);
543         exit(1);
544     }
545 
546     /* Get a UNIX socket. */
547     dev->sock = socket(AF_UNIX, SOCK_STREAM, 0);
548     if (dev->sock == -1) {
549         vubr_die("socket");
550     }
551 
552     dev->notifier.fd = -1;
553 
554     un.sun_family = AF_UNIX;
555     strcpy(un.sun_path, path);
556     len = sizeof(un.sun_family) + strlen(path);
557 
558     if (!client) {
559         unlink(path);
560 
561         if (bind(dev->sock, (struct sockaddr *) &un, len) == -1) {
562             vubr_die("bind");
563         }
564 
565         if (listen(dev->sock, 1) == -1) {
566             vubr_die("listen");
567         }
568         cb = vubr_accept_cb;
569 
570         DPRINT("Waiting for connections on UNIX socket %s ...\n", path);
571     } else {
572         if (connect(dev->sock, (struct sockaddr *)&un, len) == -1) {
573             vubr_die("connect");
574         }
575 
576         if (!vu_init(&dev->vudev,
577                      VHOST_USER_BRIDGE_MAX_QUEUES,
578                      dev->sock,
579                      vubr_panic,
580                      NULL,
581                      vubr_set_watch,
582                      vubr_remove_watch,
583                      &vuiface)) {
584             fprintf(stderr, "Failed to initialize libvhost-user\n");
585             exit(1);
586         }
587 
588         cb = vubr_receive_cb;
589     }
590 
591     dispatcher_init(&dev->dispatcher);
592 
593     dispatcher_add(&dev->dispatcher, dev->sock, (void *)dev, cb);
594 
595     return dev;
596 }
597 
598 static void *notifier_thread(void *arg)
599 {
600     VuDev *dev = (VuDev *)arg;
601     VubrDev *vubr = container_of(dev, VubrDev, vudev);
602     int pagesize = qemu_real_host_page_size();
603     int qidx;
604 
605     while (true) {
606         for (qidx = 0; qidx < VHOST_USER_BRIDGE_MAX_QUEUES; qidx++) {
607             uint16_t *n = vubr->notifier.addr + pagesize * qidx;
608 
609             if (*n == qidx) {
610                 *n = 0xffff;
611                 /* We won't miss notifications if we reset
612                  * the memory first. */
613                 smp_mb();
614 
615                 DPRINT("Got a notification for queue%d via host notifier.\n",
616                        qidx);
617 
618                 if (qidx % 2 == 1) {
619                     vubr_handle_tx(dev, qidx);
620                 }
621             }
622             usleep(1000);
623         }
624     }
625 
626     return NULL;
627 }
628 
629 static void
630 vubr_host_notifier_setup(VubrDev *dev)
631 {
632     pthread_t thread;
633     size_t length;
634     void *addr;
635     int fd;
636 
637     length = qemu_real_host_page_size() * VHOST_USER_BRIDGE_MAX_QUEUES;
638 
639     fd = g_file_open_tmp("vubr-XXXXXX", NULL, NULL);
640     if (fd < 0) {
641         vubr_die("mkstemp()");
642     }
643 
644     if (posix_fallocate(fd, 0, length) != 0) {
645         vubr_die("posix_fallocate()");
646     }
647 
648     addr = mmap(NULL, length, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
649     if (addr == MAP_FAILED) {
650         vubr_die("mmap()");
651     }
652 
653     memset(addr, 0xff, length);
654 
655     if (pthread_create(&thread, NULL, notifier_thread, &dev->vudev) != 0) {
656         vubr_die("pthread_create()");
657     }
658 
659     dev->notifier.fd = fd;
660     dev->notifier.addr = addr;
661     dev->notifier.thread = thread;
662 }
663 
664 static void
665 vubr_set_host(struct sockaddr_in *saddr, const char *host)
666 {
667     if (qemu_isdigit(host[0])) {
668         if (!inet_aton(host, &saddr->sin_addr)) {
669             fprintf(stderr, "inet_aton() failed.\n");
670             exit(1);
671         }
672     } else {
673         struct hostent *he = gethostbyname(host);
674 
675         if (!he) {
676             fprintf(stderr, "gethostbyname() failed.\n");
677             exit(1);
678         }
679         saddr->sin_addr = *(struct in_addr *)he->h_addr;
680     }
681 }
682 
683 static void
684 vubr_backend_udp_setup(VubrDev *dev,
685                        const char *local_host,
686                        const char *local_port,
687                        const char *remote_host,
688                        const char *remote_port)
689 {
690     int sock;
691     const char *r;
692 
693     int lport, rport;
694 
695     lport = strtol(local_port, (char **)&r, 0);
696     if (r == local_port) {
697         fprintf(stderr, "lport parsing failed.\n");
698         exit(1);
699     }
700 
701     rport = strtol(remote_port, (char **)&r, 0);
702     if (r == remote_port) {
703         fprintf(stderr, "rport parsing failed.\n");
704         exit(1);
705     }
706 
707     struct sockaddr_in si_local = {
708         .sin_family = AF_INET,
709         .sin_port = htons(lport),
710     };
711 
712     vubr_set_host(&si_local, local_host);
713 
714     /* setup destination for sends */
715     dev->backend_udp_dest = (struct sockaddr_in) {
716         .sin_family = AF_INET,
717         .sin_port = htons(rport),
718     };
719     vubr_set_host(&dev->backend_udp_dest, remote_host);
720 
721     sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
722     if (sock == -1) {
723         vubr_die("socket");
724     }
725 
726     if (bind(sock, (struct sockaddr *)&si_local, sizeof(si_local)) == -1) {
727         vubr_die("bind");
728     }
729 
730     dev->backend_udp_sock = sock;
731     dispatcher_add(&dev->dispatcher, sock, dev, vubr_backend_recv_cb);
732     DPRINT("Waiting for data from udp backend on %s:%d...\n",
733            local_host, lport);
734 }
735 
736 static void
737 vubr_run(VubrDev *dev)
738 {
739     while (!dev->quit) {
740         /* timeout 200ms */
741         dispatcher_wait(&dev->dispatcher, 200000);
742         /* Here one can try polling strategy. */
743     }
744 }
745 
746 static int
747 vubr_parse_host_port(const char **host, const char **port, const char *buf)
748 {
749     char *p = strchr(buf, ':');
750 
751     if (!p) {
752         return -1;
753     }
754     *p = '\0';
755     *host = strdup(buf);
756     *port = strdup(p + 1);
757     return 0;
758 }
759 
760 #define DEFAULT_UD_SOCKET "/tmp/vubr.sock"
761 #define DEFAULT_LHOST "127.0.0.1"
762 #define DEFAULT_LPORT "4444"
763 #define DEFAULT_RHOST "127.0.0.1"
764 #define DEFAULT_RPORT "5555"
765 
766 static const char *ud_socket_path = DEFAULT_UD_SOCKET;
767 static const char *lhost = DEFAULT_LHOST;
768 static const char *lport = DEFAULT_LPORT;
769 static const char *rhost = DEFAULT_RHOST;
770 static const char *rport = DEFAULT_RPORT;
771 
772 int
773 main(int argc, char *argv[])
774 {
775     VubrDev *dev;
776     int opt;
777     bool client = false;
778     bool host_notifier = false;
779 
780     while ((opt = getopt(argc, argv, "l:r:u:cH")) != -1) {
781 
782         switch (opt) {
783         case 'l':
784             if (vubr_parse_host_port(&lhost, &lport, optarg) < 0) {
785                 goto out;
786             }
787             break;
788         case 'r':
789             if (vubr_parse_host_port(&rhost, &rport, optarg) < 0) {
790                 goto out;
791             }
792             break;
793         case 'u':
794             ud_socket_path = strdup(optarg);
795             break;
796         case 'c':
797             client = true;
798             break;
799         case 'H':
800             host_notifier = true;
801             break;
802         default:
803             goto out;
804         }
805     }
806 
807     DPRINT("ud socket: %s (%s)\n", ud_socket_path,
808            client ? "client" : "server");
809     DPRINT("local:     %s:%s\n", lhost, lport);
810     DPRINT("remote:    %s:%s\n", rhost, rport);
811 
812     dev = vubr_new(ud_socket_path, client);
813     if (!dev) {
814         return 1;
815     }
816 
817     if (host_notifier) {
818         vubr_host_notifier_setup(dev);
819     }
820 
821     vubr_backend_udp_setup(dev, lhost, lport, rhost, rport);
822     vubr_run(dev);
823 
824     vu_deinit(&dev->vudev);
825 
826     return 0;
827 
828 out:
829     fprintf(stderr, "Usage: %s ", argv[0]);
830     fprintf(stderr, "[-c] [-H] [-u ud_socket_path] [-l lhost:lport] [-r rhost:rport]\n");
831     fprintf(stderr, "\t-u path to unix domain socket. default: %s\n",
832             DEFAULT_UD_SOCKET);
833     fprintf(stderr, "\t-l local host and port. default: %s:%s\n",
834             DEFAULT_LHOST, DEFAULT_LPORT);
835     fprintf(stderr, "\t-r remote host and port. default: %s:%s\n",
836             DEFAULT_RHOST, DEFAULT_RPORT);
837     fprintf(stderr, "\t-c client mode\n");
838     fprintf(stderr, "\t-H use host notifier\n");
839 
840     return 1;
841 }
842