xref: /qemu/tests/vhost-user-bridge.c (revision 3d1ad18c4257471cd5fda8397a46457735027b2c)
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 <sys/socket.h>
34 #include <sys/un.h>
35 #include <sys/unistd.h>
36 #include <sys/eventfd.h>
37 #include <arpa/inet.h>
38 #include <netdb.h>
39 #include <linux/vhost.h>
40 
41 #include "qemu/atomic.h"
42 #include "standard-headers/linux/virtio_net.h"
43 #include "standard-headers/linux/virtio_ring.h"
44 
45 #define VHOST_USER_BRIDGE_DEBUG 1
46 
47 #define DPRINT(...) \
48     do { \
49         if (VHOST_USER_BRIDGE_DEBUG) { \
50             printf(__VA_ARGS__); \
51         } \
52     } while (0)
53 
54 typedef void (*CallbackFunc)(int sock, void *ctx);
55 
56 typedef struct Event {
57     void *ctx;
58     CallbackFunc callback;
59 } Event;
60 
61 typedef struct Dispatcher {
62     int max_sock;
63     fd_set fdset;
64     Event events[FD_SETSIZE];
65 } Dispatcher;
66 
67 static void
68 vubr_die(const char *s)
69 {
70     perror(s);
71     exit(1);
72 }
73 
74 static int
75 dispatcher_init(Dispatcher *dispr)
76 {
77     FD_ZERO(&dispr->fdset);
78     dispr->max_sock = -1;
79     return 0;
80 }
81 
82 static int
83 dispatcher_add(Dispatcher *dispr, int sock, void *ctx, CallbackFunc cb)
84 {
85     if (sock >= FD_SETSIZE) {
86         fprintf(stderr,
87                 "Error: Failed to add new event. sock %d should be less than %d\n",
88                 sock, FD_SETSIZE);
89         return -1;
90     }
91 
92     dispr->events[sock].ctx = ctx;
93     dispr->events[sock].callback = cb;
94 
95     FD_SET(sock, &dispr->fdset);
96     if (sock > dispr->max_sock) {
97         dispr->max_sock = sock;
98     }
99     DPRINT("Added sock %d for watching. max_sock: %d\n",
100            sock, dispr->max_sock);
101     return 0;
102 }
103 
104 static int
105 dispatcher_remove(Dispatcher *dispr, int sock)
106 {
107     if (sock >= FD_SETSIZE) {
108         fprintf(stderr,
109                 "Error: Failed to remove event. sock %d should be less than %d\n",
110                 sock, FD_SETSIZE);
111         return -1;
112     }
113 
114     FD_CLR(sock, &dispr->fdset);
115     DPRINT("Sock %d removed from dispatcher watch.\n", sock);
116     return 0;
117 }
118 
119 /* timeout in us */
120 static int
121 dispatcher_wait(Dispatcher *dispr, uint32_t timeout)
122 {
123     struct timeval tv;
124     tv.tv_sec = timeout / 1000000;
125     tv.tv_usec = timeout % 1000000;
126 
127     fd_set fdset = dispr->fdset;
128 
129     /* wait until some of sockets become readable. */
130     int rc = select(dispr->max_sock + 1, &fdset, 0, 0, &tv);
131 
132     if (rc == -1) {
133         vubr_die("select");
134     }
135 
136     /* Timeout */
137     if (rc == 0) {
138         return 0;
139     }
140 
141     /* Now call callback for every ready socket. */
142 
143     int sock;
144     for (sock = 0; sock < dispr->max_sock + 1; sock++) {
145         /* The callback on a socket can remove other sockets from the
146          * dispatcher, thus we have to check that the socket is
147          * still not removed from dispatcher's list
148          */
149         if (FD_ISSET(sock, &fdset) && FD_ISSET(sock, &dispr->fdset)) {
150             Event *e = &dispr->events[sock];
151             e->callback(sock, e->ctx);
152         }
153     }
154 
155     return 0;
156 }
157 
158 typedef struct VubrVirtq {
159     int call_fd;
160     int kick_fd;
161     uint32_t size;
162     uint16_t last_avail_index;
163     uint16_t last_used_index;
164     struct vring_desc *desc;
165     struct vring_avail *avail;
166     struct vring_used *used;
167     uint64_t log_guest_addr;
168     int enable;
169 } VubrVirtq;
170 
171 /* Based on qemu/hw/virtio/vhost-user.c */
172 
173 #define VHOST_MEMORY_MAX_NREGIONS    8
174 #define VHOST_USER_F_PROTOCOL_FEATURES 30
175 /* v1.0 compliant. */
176 #define VIRTIO_F_VERSION_1		32
177 
178 #define VHOST_LOG_PAGE 4096
179 
180 enum VhostUserProtocolFeature {
181     VHOST_USER_PROTOCOL_F_MQ = 0,
182     VHOST_USER_PROTOCOL_F_LOG_SHMFD = 1,
183     VHOST_USER_PROTOCOL_F_RARP = 2,
184 
185     VHOST_USER_PROTOCOL_F_MAX
186 };
187 
188 #define VHOST_USER_PROTOCOL_FEATURE_MASK ((1 << VHOST_USER_PROTOCOL_F_MAX) - 1)
189 
190 typedef enum VhostUserRequest {
191     VHOST_USER_NONE = 0,
192     VHOST_USER_GET_FEATURES = 1,
193     VHOST_USER_SET_FEATURES = 2,
194     VHOST_USER_SET_OWNER = 3,
195     VHOST_USER_RESET_OWNER = 4,
196     VHOST_USER_SET_MEM_TABLE = 5,
197     VHOST_USER_SET_LOG_BASE = 6,
198     VHOST_USER_SET_LOG_FD = 7,
199     VHOST_USER_SET_VRING_NUM = 8,
200     VHOST_USER_SET_VRING_ADDR = 9,
201     VHOST_USER_SET_VRING_BASE = 10,
202     VHOST_USER_GET_VRING_BASE = 11,
203     VHOST_USER_SET_VRING_KICK = 12,
204     VHOST_USER_SET_VRING_CALL = 13,
205     VHOST_USER_SET_VRING_ERR = 14,
206     VHOST_USER_GET_PROTOCOL_FEATURES = 15,
207     VHOST_USER_SET_PROTOCOL_FEATURES = 16,
208     VHOST_USER_GET_QUEUE_NUM = 17,
209     VHOST_USER_SET_VRING_ENABLE = 18,
210     VHOST_USER_SEND_RARP = 19,
211     VHOST_USER_MAX
212 } VhostUserRequest;
213 
214 typedef struct VhostUserMemoryRegion {
215     uint64_t guest_phys_addr;
216     uint64_t memory_size;
217     uint64_t userspace_addr;
218     uint64_t mmap_offset;
219 } VhostUserMemoryRegion;
220 
221 typedef struct VhostUserMemory {
222     uint32_t nregions;
223     uint32_t padding;
224     VhostUserMemoryRegion regions[VHOST_MEMORY_MAX_NREGIONS];
225 } VhostUserMemory;
226 
227 typedef struct VhostUserLog {
228     uint64_t mmap_size;
229     uint64_t mmap_offset;
230 } VhostUserLog;
231 
232 typedef struct VhostUserMsg {
233     VhostUserRequest request;
234 
235 #define VHOST_USER_VERSION_MASK     (0x3)
236 #define VHOST_USER_REPLY_MASK       (0x1<<2)
237     uint32_t flags;
238     uint32_t size; /* the following payload size */
239     union {
240 #define VHOST_USER_VRING_IDX_MASK   (0xff)
241 #define VHOST_USER_VRING_NOFD_MASK  (0x1<<8)
242         uint64_t u64;
243         struct vhost_vring_state state;
244         struct vhost_vring_addr addr;
245         VhostUserMemory memory;
246         VhostUserLog log;
247     } payload;
248     int fds[VHOST_MEMORY_MAX_NREGIONS];
249     int fd_num;
250 } QEMU_PACKED VhostUserMsg;
251 
252 #define VHOST_USER_HDR_SIZE offsetof(VhostUserMsg, payload.u64)
253 
254 /* The version of the protocol we support */
255 #define VHOST_USER_VERSION    (0x1)
256 
257 #define MAX_NR_VIRTQUEUE (8)
258 
259 typedef struct VubrDevRegion {
260     /* Guest Physical address. */
261     uint64_t gpa;
262     /* Memory region size. */
263     uint64_t size;
264     /* QEMU virtual address (userspace). */
265     uint64_t qva;
266     /* Starting offset in our mmaped space. */
267     uint64_t mmap_offset;
268     /* Start address of mmaped space. */
269     uint64_t mmap_addr;
270 } VubrDevRegion;
271 
272 typedef struct VubrDev {
273     int sock;
274     Dispatcher dispatcher;
275     uint32_t nregions;
276     VubrDevRegion regions[VHOST_MEMORY_MAX_NREGIONS];
277     VubrVirtq vq[MAX_NR_VIRTQUEUE];
278     int log_call_fd;
279     uint64_t log_size;
280     uint8_t *log_table;
281     int backend_udp_sock;
282     struct sockaddr_in backend_udp_dest;
283     int ready;
284     uint64_t features;
285     int hdrlen;
286 } VubrDev;
287 
288 static const char *vubr_request_str[] = {
289     [VHOST_USER_NONE]                   =  "VHOST_USER_NONE",
290     [VHOST_USER_GET_FEATURES]           =  "VHOST_USER_GET_FEATURES",
291     [VHOST_USER_SET_FEATURES]           =  "VHOST_USER_SET_FEATURES",
292     [VHOST_USER_SET_OWNER]              =  "VHOST_USER_SET_OWNER",
293     [VHOST_USER_RESET_OWNER]           =  "VHOST_USER_RESET_OWNER",
294     [VHOST_USER_SET_MEM_TABLE]          =  "VHOST_USER_SET_MEM_TABLE",
295     [VHOST_USER_SET_LOG_BASE]           =  "VHOST_USER_SET_LOG_BASE",
296     [VHOST_USER_SET_LOG_FD]             =  "VHOST_USER_SET_LOG_FD",
297     [VHOST_USER_SET_VRING_NUM]          =  "VHOST_USER_SET_VRING_NUM",
298     [VHOST_USER_SET_VRING_ADDR]         =  "VHOST_USER_SET_VRING_ADDR",
299     [VHOST_USER_SET_VRING_BASE]         =  "VHOST_USER_SET_VRING_BASE",
300     [VHOST_USER_GET_VRING_BASE]         =  "VHOST_USER_GET_VRING_BASE",
301     [VHOST_USER_SET_VRING_KICK]         =  "VHOST_USER_SET_VRING_KICK",
302     [VHOST_USER_SET_VRING_CALL]         =  "VHOST_USER_SET_VRING_CALL",
303     [VHOST_USER_SET_VRING_ERR]          =  "VHOST_USER_SET_VRING_ERR",
304     [VHOST_USER_GET_PROTOCOL_FEATURES]  =  "VHOST_USER_GET_PROTOCOL_FEATURES",
305     [VHOST_USER_SET_PROTOCOL_FEATURES]  =  "VHOST_USER_SET_PROTOCOL_FEATURES",
306     [VHOST_USER_GET_QUEUE_NUM]          =  "VHOST_USER_GET_QUEUE_NUM",
307     [VHOST_USER_SET_VRING_ENABLE]       =  "VHOST_USER_SET_VRING_ENABLE",
308     [VHOST_USER_SEND_RARP]              =  "VHOST_USER_SEND_RARP",
309     [VHOST_USER_MAX]                    =  "VHOST_USER_MAX",
310 };
311 
312 static void
313 print_buffer(uint8_t *buf, size_t len)
314 {
315     int i;
316     printf("Raw buffer:\n");
317     for (i = 0; i < len; i++) {
318         if (i % 16 == 0) {
319             printf("\n");
320         }
321         if (i % 4 == 0) {
322             printf("   ");
323         }
324         printf("%02x ", buf[i]);
325     }
326     printf("\n............................................................\n");
327 }
328 
329 /* Translate guest physical address to our virtual address.  */
330 static uint64_t
331 gpa_to_va(VubrDev *dev, uint64_t guest_addr)
332 {
333     int i;
334 
335     /* Find matching memory region.  */
336     for (i = 0; i < dev->nregions; i++) {
337         VubrDevRegion *r = &dev->regions[i];
338 
339         if ((guest_addr >= r->gpa) && (guest_addr < (r->gpa + r->size))) {
340             return guest_addr - r->gpa + r->mmap_addr + r->mmap_offset;
341         }
342     }
343 
344     assert(!"address not found in regions");
345     return 0;
346 }
347 
348 /* Translate qemu virtual address to our virtual address.  */
349 static uint64_t
350 qva_to_va(VubrDev *dev, uint64_t qemu_addr)
351 {
352     int i;
353 
354     /* Find matching memory region.  */
355     for (i = 0; i < dev->nregions; i++) {
356         VubrDevRegion *r = &dev->regions[i];
357 
358         if ((qemu_addr >= r->qva) && (qemu_addr < (r->qva + r->size))) {
359             return qemu_addr - r->qva + r->mmap_addr + r->mmap_offset;
360         }
361     }
362 
363     assert(!"address not found in regions");
364     return 0;
365 }
366 
367 static void
368 vubr_message_read(int conn_fd, VhostUserMsg *vmsg)
369 {
370     char control[CMSG_SPACE(VHOST_MEMORY_MAX_NREGIONS * sizeof(int))] = { };
371     struct iovec iov = {
372         .iov_base = (char *)vmsg,
373         .iov_len = VHOST_USER_HDR_SIZE,
374     };
375     struct msghdr msg = {
376         .msg_iov = &iov,
377         .msg_iovlen = 1,
378         .msg_control = control,
379         .msg_controllen = sizeof(control),
380     };
381     size_t fd_size;
382     struct cmsghdr *cmsg;
383     int rc;
384 
385     rc = recvmsg(conn_fd, &msg, 0);
386 
387     if (rc == 0) {
388         vubr_die("recvmsg");
389         fprintf(stderr, "Peer disconnected.\n");
390         exit(1);
391     }
392     if (rc < 0) {
393         vubr_die("recvmsg");
394     }
395 
396     vmsg->fd_num = 0;
397     for (cmsg = CMSG_FIRSTHDR(&msg);
398          cmsg != NULL;
399          cmsg = CMSG_NXTHDR(&msg, cmsg))
400     {
401         if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
402             fd_size = cmsg->cmsg_len - CMSG_LEN(0);
403             vmsg->fd_num = fd_size / sizeof(int);
404             memcpy(vmsg->fds, CMSG_DATA(cmsg), fd_size);
405             break;
406         }
407     }
408 
409     if (vmsg->size > sizeof(vmsg->payload)) {
410         fprintf(stderr,
411                 "Error: too big message request: %d, size: vmsg->size: %u, "
412                 "while sizeof(vmsg->payload) = %zu\n",
413                 vmsg->request, vmsg->size, sizeof(vmsg->payload));
414         exit(1);
415     }
416 
417     if (vmsg->size) {
418         rc = read(conn_fd, &vmsg->payload, vmsg->size);
419         if (rc == 0) {
420             vubr_die("recvmsg");
421             fprintf(stderr, "Peer disconnected.\n");
422             exit(1);
423         }
424         if (rc < 0) {
425             vubr_die("recvmsg");
426         }
427 
428         assert(rc == vmsg->size);
429     }
430 }
431 
432 static void
433 vubr_message_write(int conn_fd, VhostUserMsg *vmsg)
434 {
435     int rc;
436 
437     do {
438         rc = write(conn_fd, vmsg, VHOST_USER_HDR_SIZE + vmsg->size);
439     } while (rc < 0 && errno == EINTR);
440 
441     if (rc < 0) {
442         vubr_die("write");
443     }
444 }
445 
446 static void
447 vubr_backend_udp_sendbuf(VubrDev *dev, uint8_t *buf, size_t len)
448 {
449     int slen = sizeof(struct sockaddr_in);
450 
451     if (sendto(dev->backend_udp_sock, buf, len, 0,
452                (struct sockaddr *) &dev->backend_udp_dest, slen) == -1) {
453         vubr_die("sendto()");
454     }
455 }
456 
457 static int
458 vubr_backend_udp_recvbuf(VubrDev *dev, uint8_t *buf, size_t buflen)
459 {
460     int slen = sizeof(struct sockaddr_in);
461     int rc;
462 
463     rc = recvfrom(dev->backend_udp_sock, buf, buflen, 0,
464                   (struct sockaddr *) &dev->backend_udp_dest,
465                   (socklen_t *)&slen);
466     if (rc == -1) {
467         vubr_die("recvfrom()");
468     }
469 
470     return rc;
471 }
472 
473 static void
474 vubr_consume_raw_packet(VubrDev *dev, uint8_t *buf, uint32_t len)
475 {
476     int hdrlen = dev->hdrlen;
477     DPRINT("    hdrlen = %d\n", dev->hdrlen);
478 
479     if (VHOST_USER_BRIDGE_DEBUG) {
480         print_buffer(buf, len);
481     }
482     vubr_backend_udp_sendbuf(dev, buf + hdrlen, len - hdrlen);
483 }
484 
485 /* Kick the log_call_fd if required. */
486 static void
487 vubr_log_kick(VubrDev *dev)
488 {
489     if (dev->log_call_fd != -1) {
490         DPRINT("Kicking the QEMU's log...\n");
491         eventfd_write(dev->log_call_fd, 1);
492     }
493 }
494 
495 /* Kick the guest if necessary. */
496 static void
497 vubr_virtqueue_kick(VubrVirtq *vq)
498 {
499     if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)) {
500         DPRINT("Kicking the guest...\n");
501         eventfd_write(vq->call_fd, 1);
502     }
503 }
504 
505 static void
506 vubr_log_page(uint8_t *log_table, uint64_t page)
507 {
508     DPRINT("Logged dirty guest page: %"PRId64"\n", page);
509     atomic_or(&log_table[page / 8], 1 << (page % 8));
510 }
511 
512 static void
513 vubr_log_write(VubrDev *dev, uint64_t address, uint64_t length)
514 {
515     uint64_t page;
516 
517     if (!(dev->features & (1ULL << VHOST_F_LOG_ALL)) ||
518         !dev->log_table || !length) {
519         return;
520     }
521 
522     assert(dev->log_size > ((address + length - 1) / VHOST_LOG_PAGE / 8));
523 
524     page = address / VHOST_LOG_PAGE;
525     while (page * VHOST_LOG_PAGE < address + length) {
526         vubr_log_page(dev->log_table, page);
527         page += VHOST_LOG_PAGE;
528     }
529     vubr_log_kick(dev);
530 }
531 
532 static void
533 vubr_post_buffer(VubrDev *dev, VubrVirtq *vq, uint8_t *buf, int32_t len)
534 {
535     struct vring_desc *desc = vq->desc;
536     struct vring_avail *avail = vq->avail;
537     struct vring_used *used = vq->used;
538     uint64_t log_guest_addr = vq->log_guest_addr;
539     int32_t remaining_len = len;
540 
541     unsigned int size = vq->size;
542 
543     uint16_t avail_index = atomic_mb_read(&avail->idx);
544 
545     /* We check the available descriptors before posting the
546      * buffer, so here we assume that enough available
547      * descriptors. */
548     assert(vq->last_avail_index != avail_index);
549     uint16_t a_index = vq->last_avail_index % size;
550     uint16_t u_index = vq->last_used_index % size;
551     uint16_t d_index = avail->ring[a_index];
552 
553     int i = d_index;
554     uint32_t written_len = 0;
555 
556     do {
557         DPRINT("Post packet to guest on vq:\n");
558         DPRINT("    size             = %d\n", vq->size);
559         DPRINT("    last_avail_index = %d\n", vq->last_avail_index);
560         DPRINT("    last_used_index  = %d\n", vq->last_used_index);
561         DPRINT("    a_index = %d\n", a_index);
562         DPRINT("    u_index = %d\n", u_index);
563         DPRINT("    d_index = %d\n", d_index);
564         DPRINT("    desc[%d].addr    = 0x%016"PRIx64"\n", i, desc[i].addr);
565         DPRINT("    desc[%d].len     = %d\n", i, desc[i].len);
566         DPRINT("    desc[%d].flags   = %d\n", i, desc[i].flags);
567         DPRINT("    avail->idx = %d\n", avail_index);
568         DPRINT("    used->idx  = %d\n", used->idx);
569 
570         if (!(desc[i].flags & VRING_DESC_F_WRITE)) {
571             /* FIXME: we should find writable descriptor. */
572             fprintf(stderr, "Error: descriptor is not writable. Exiting.\n");
573             exit(1);
574         }
575 
576         void *chunk_start = (void *)(uintptr_t)gpa_to_va(dev, desc[i].addr);
577         uint32_t chunk_len = desc[i].len;
578         uint32_t chunk_write_len = MIN(remaining_len, chunk_len);
579 
580         memcpy(chunk_start, buf + written_len, chunk_write_len);
581         vubr_log_write(dev, desc[i].addr, chunk_write_len);
582         remaining_len -= chunk_write_len;
583         written_len += chunk_write_len;
584 
585         if ((remaining_len == 0) || !(desc[i].flags & VRING_DESC_F_NEXT)) {
586             break;
587         }
588 
589         i = desc[i].next;
590     } while (1);
591 
592     if (remaining_len > 0) {
593             fprintf(stderr,
594                     "Too long packet for RX, remaining_len = %d, Dropping...\n",
595                     remaining_len);
596             return;
597     }
598 
599     /* Add descriptor to the used ring. */
600     used->ring[u_index].id = d_index;
601     used->ring[u_index].len = len;
602     vubr_log_write(dev,
603                    log_guest_addr + offsetof(struct vring_used, ring[u_index]),
604                    sizeof(used->ring[u_index]));
605 
606     vq->last_avail_index++;
607     vq->last_used_index++;
608 
609     atomic_mb_set(&used->idx, vq->last_used_index);
610     vubr_log_write(dev,
611                    log_guest_addr + offsetof(struct vring_used, idx),
612                    sizeof(used->idx));
613 
614     /* Kick the guest if necessary. */
615     vubr_virtqueue_kick(vq);
616 }
617 
618 static int
619 vubr_process_desc(VubrDev *dev, VubrVirtq *vq)
620 {
621     struct vring_desc *desc = vq->desc;
622     struct vring_avail *avail = vq->avail;
623     struct vring_used *used = vq->used;
624     uint64_t log_guest_addr = vq->log_guest_addr;
625 
626     unsigned int size = vq->size;
627 
628     uint16_t a_index = vq->last_avail_index % size;
629     uint16_t u_index = vq->last_used_index % size;
630     uint16_t d_index = avail->ring[a_index];
631 
632     uint32_t i, len = 0;
633     size_t buf_size = 4096;
634     uint8_t buf[4096];
635 
636     DPRINT("Chunks: ");
637     i = d_index;
638     do {
639         void *chunk_start = (void *)(uintptr_t)gpa_to_va(dev, desc[i].addr);
640         uint32_t chunk_len = desc[i].len;
641 
642         assert(!(desc[i].flags & VRING_DESC_F_WRITE));
643 
644         if (len + chunk_len < buf_size) {
645             memcpy(buf + len, chunk_start, chunk_len);
646             DPRINT("%d ", chunk_len);
647         } else {
648             fprintf(stderr, "Error: too long packet. Dropping...\n");
649             break;
650         }
651 
652         len += chunk_len;
653 
654         if (!(desc[i].flags & VRING_DESC_F_NEXT)) {
655             break;
656         }
657 
658         i = desc[i].next;
659     } while (1);
660     DPRINT("\n");
661 
662     if (!len) {
663         return -1;
664     }
665 
666     /* Add descriptor to the used ring. */
667     used->ring[u_index].id = d_index;
668     used->ring[u_index].len = len;
669     vubr_log_write(dev,
670                    log_guest_addr + offsetof(struct vring_used, ring[u_index]),
671                    sizeof(used->ring[u_index]));
672 
673     vubr_consume_raw_packet(dev, buf, len);
674 
675     return 0;
676 }
677 
678 static void
679 vubr_process_avail(VubrDev *dev, VubrVirtq *vq)
680 {
681     struct vring_avail *avail = vq->avail;
682     struct vring_used *used = vq->used;
683     uint64_t log_guest_addr = vq->log_guest_addr;
684 
685     while (vq->last_avail_index != atomic_mb_read(&avail->idx)) {
686         vubr_process_desc(dev, vq);
687         vq->last_avail_index++;
688         vq->last_used_index++;
689     }
690 
691     atomic_mb_set(&used->idx, vq->last_used_index);
692     vubr_log_write(dev,
693                    log_guest_addr + offsetof(struct vring_used, idx),
694                    sizeof(used->idx));
695 }
696 
697 static void
698 vubr_backend_recv_cb(int sock, void *ctx)
699 {
700     VubrDev *dev = (VubrDev *) ctx;
701     VubrVirtq *rx_vq = &dev->vq[0];
702     uint8_t buf[4096];
703     struct virtio_net_hdr_v1 *hdr = (struct virtio_net_hdr_v1 *)buf;
704     int hdrlen = dev->hdrlen;
705     int buflen = sizeof(buf);
706     int len;
707 
708     if (!dev->ready) {
709         return;
710     }
711 
712     DPRINT("\n\n   ***   IN UDP RECEIVE CALLBACK    ***\n\n");
713     DPRINT("    hdrlen = %d\n", hdrlen);
714 
715     uint16_t avail_index = atomic_mb_read(&rx_vq->avail->idx);
716 
717     /* If there is no available descriptors, just do nothing.
718      * The buffer will be handled by next arrived UDP packet,
719      * or next kick on receive virtq. */
720     if (rx_vq->last_avail_index == avail_index) {
721         DPRINT("Got UDP packet, but no available descriptors on RX virtq.\n");
722         return;
723     }
724 
725     memset(buf, 0, hdrlen);
726     /* TODO: support mergeable buffers. */
727     if (hdrlen == 12)
728         hdr->num_buffers = 1;
729     len = vubr_backend_udp_recvbuf(dev, buf + hdrlen, buflen - hdrlen);
730 
731     vubr_post_buffer(dev, rx_vq, buf, len + hdrlen);
732 }
733 
734 static void
735 vubr_kick_cb(int sock, void *ctx)
736 {
737     VubrDev *dev = (VubrDev *) ctx;
738     eventfd_t kick_data;
739     ssize_t rc;
740 
741     rc = eventfd_read(sock, &kick_data);
742     if (rc == -1) {
743         vubr_die("eventfd_read()");
744     } else {
745         DPRINT("Got kick_data: %016"PRIx64"\n", kick_data);
746         vubr_process_avail(dev, &dev->vq[1]);
747     }
748 }
749 
750 static int
751 vubr_none_exec(VubrDev *dev, VhostUserMsg *vmsg)
752 {
753     DPRINT("Function %s() not implemented yet.\n", __func__);
754     return 0;
755 }
756 
757 static int
758 vubr_get_features_exec(VubrDev *dev, VhostUserMsg *vmsg)
759 {
760     vmsg->payload.u64 =
761             ((1ULL << VIRTIO_NET_F_MRG_RXBUF) |
762              (1ULL << VHOST_F_LOG_ALL) |
763              (1ULL << VIRTIO_NET_F_GUEST_ANNOUNCE) |
764              (1ULL << VHOST_USER_F_PROTOCOL_FEATURES));
765 
766     vmsg->size = sizeof(vmsg->payload.u64);
767 
768     DPRINT("Sending back to guest u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
769 
770     /* Reply */
771     return 1;
772 }
773 
774 static int
775 vubr_set_features_exec(VubrDev *dev, VhostUserMsg *vmsg)
776 {
777     DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
778 
779     dev->features = vmsg->payload.u64;
780     if ((dev->features & (1ULL << VIRTIO_F_VERSION_1)) ||
781         (dev->features & (1ULL << VIRTIO_NET_F_MRG_RXBUF))) {
782         dev->hdrlen = 12;
783     } else {
784         dev->hdrlen = 10;
785     }
786 
787     return 0;
788 }
789 
790 static int
791 vubr_set_owner_exec(VubrDev *dev, VhostUserMsg *vmsg)
792 {
793     return 0;
794 }
795 
796 static void
797 vubr_close_log(VubrDev *dev)
798 {
799     if (dev->log_table) {
800         if (munmap(dev->log_table, dev->log_size) != 0) {
801             vubr_die("munmap()");
802         }
803 
804         dev->log_table = 0;
805     }
806     if (dev->log_call_fd != -1) {
807         close(dev->log_call_fd);
808         dev->log_call_fd = -1;
809     }
810 }
811 
812 static int
813 vubr_reset_device_exec(VubrDev *dev, VhostUserMsg *vmsg)
814 {
815     vubr_close_log(dev);
816     dev->ready = 0;
817     dev->features = 0;
818     return 0;
819 }
820 
821 static int
822 vubr_set_mem_table_exec(VubrDev *dev, VhostUserMsg *vmsg)
823 {
824     int i;
825     VhostUserMemory *memory = &vmsg->payload.memory;
826     dev->nregions = memory->nregions;
827 
828     DPRINT("Nregions: %d\n", memory->nregions);
829     for (i = 0; i < dev->nregions; i++) {
830         void *mmap_addr;
831         VhostUserMemoryRegion *msg_region = &memory->regions[i];
832         VubrDevRegion *dev_region = &dev->regions[i];
833 
834         DPRINT("Region %d\n", i);
835         DPRINT("    guest_phys_addr: 0x%016"PRIx64"\n",
836                msg_region->guest_phys_addr);
837         DPRINT("    memory_size:     0x%016"PRIx64"\n",
838                msg_region->memory_size);
839         DPRINT("    userspace_addr   0x%016"PRIx64"\n",
840                msg_region->userspace_addr);
841         DPRINT("    mmap_offset      0x%016"PRIx64"\n",
842                msg_region->mmap_offset);
843 
844         dev_region->gpa = msg_region->guest_phys_addr;
845         dev_region->size = msg_region->memory_size;
846         dev_region->qva = msg_region->userspace_addr;
847         dev_region->mmap_offset = msg_region->mmap_offset;
848 
849         /* We don't use offset argument of mmap() since the
850          * mapped address has to be page aligned, and we use huge
851          * pages.  */
852         mmap_addr = mmap(0, dev_region->size + dev_region->mmap_offset,
853                          PROT_READ | PROT_WRITE, MAP_SHARED,
854                          vmsg->fds[i], 0);
855 
856         if (mmap_addr == MAP_FAILED) {
857             vubr_die("mmap");
858         }
859         dev_region->mmap_addr = (uint64_t)(uintptr_t)mmap_addr;
860         DPRINT("    mmap_addr:       0x%016"PRIx64"\n", dev_region->mmap_addr);
861 
862         close(vmsg->fds[i]);
863     }
864 
865     return 0;
866 }
867 
868 static int
869 vubr_set_log_base_exec(VubrDev *dev, VhostUserMsg *vmsg)
870 {
871     int fd;
872     uint64_t log_mmap_size, log_mmap_offset;
873     void *rc;
874 
875     assert(vmsg->fd_num == 1);
876     fd = vmsg->fds[0];
877 
878     assert(vmsg->size == sizeof(vmsg->payload.log));
879     log_mmap_offset = vmsg->payload.log.mmap_offset;
880     log_mmap_size = vmsg->payload.log.mmap_size;
881     DPRINT("Log mmap_offset: %"PRId64"\n", log_mmap_offset);
882     DPRINT("Log mmap_size:   %"PRId64"\n", log_mmap_size);
883 
884     rc = mmap(0, log_mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd,
885               log_mmap_offset);
886     if (rc == MAP_FAILED) {
887         vubr_die("mmap");
888     }
889     dev->log_table = rc;
890     dev->log_size = log_mmap_size;
891 
892     vmsg->size = sizeof(vmsg->payload.u64);
893     /* Reply */
894     return 1;
895 }
896 
897 static int
898 vubr_set_log_fd_exec(VubrDev *dev, VhostUserMsg *vmsg)
899 {
900     assert(vmsg->fd_num == 1);
901     dev->log_call_fd = vmsg->fds[0];
902     DPRINT("Got log_call_fd: %d\n", vmsg->fds[0]);
903     return 0;
904 }
905 
906 static int
907 vubr_set_vring_num_exec(VubrDev *dev, VhostUserMsg *vmsg)
908 {
909     unsigned int index = vmsg->payload.state.index;
910     unsigned int num = vmsg->payload.state.num;
911 
912     DPRINT("State.index: %d\n", index);
913     DPRINT("State.num:   %d\n", num);
914     dev->vq[index].size = num;
915     return 0;
916 }
917 
918 static int
919 vubr_set_vring_addr_exec(VubrDev *dev, VhostUserMsg *vmsg)
920 {
921     struct vhost_vring_addr *vra = &vmsg->payload.addr;
922     unsigned int index = vra->index;
923     VubrVirtq *vq = &dev->vq[index];
924 
925     DPRINT("vhost_vring_addr:\n");
926     DPRINT("    index:  %d\n", vra->index);
927     DPRINT("    flags:  %d\n", vra->flags);
928     DPRINT("    desc_user_addr:   0x%016llx\n", vra->desc_user_addr);
929     DPRINT("    used_user_addr:   0x%016llx\n", vra->used_user_addr);
930     DPRINT("    avail_user_addr:  0x%016llx\n", vra->avail_user_addr);
931     DPRINT("    log_guest_addr:   0x%016llx\n", vra->log_guest_addr);
932 
933     vq->desc = (struct vring_desc *)(uintptr_t)qva_to_va(dev, vra->desc_user_addr);
934     vq->used = (struct vring_used *)(uintptr_t)qva_to_va(dev, vra->used_user_addr);
935     vq->avail = (struct vring_avail *)(uintptr_t)qva_to_va(dev, vra->avail_user_addr);
936     vq->log_guest_addr = vra->log_guest_addr;
937 
938     DPRINT("Setting virtq addresses:\n");
939     DPRINT("    vring_desc  at %p\n", vq->desc);
940     DPRINT("    vring_used  at %p\n", vq->used);
941     DPRINT("    vring_avail at %p\n", vq->avail);
942 
943     vq->last_used_index = vq->used->idx;
944 
945     if (vq->last_avail_index != vq->used->idx) {
946         DPRINT("Last avail index != used index: %d != %d, resuming",
947                vq->last_avail_index, vq->used->idx);
948         vq->last_avail_index = vq->used->idx;
949     }
950 
951     return 0;
952 }
953 
954 static int
955 vubr_set_vring_base_exec(VubrDev *dev, VhostUserMsg *vmsg)
956 {
957     unsigned int index = vmsg->payload.state.index;
958     unsigned int num = vmsg->payload.state.num;
959 
960     DPRINT("State.index: %d\n", index);
961     DPRINT("State.num:   %d\n", num);
962     dev->vq[index].last_avail_index = num;
963 
964     return 0;
965 }
966 
967 static int
968 vubr_get_vring_base_exec(VubrDev *dev, VhostUserMsg *vmsg)
969 {
970     unsigned int index = vmsg->payload.state.index;
971 
972     DPRINT("State.index: %d\n", index);
973     vmsg->payload.state.num = dev->vq[index].last_avail_index;
974     vmsg->size = sizeof(vmsg->payload.state);
975     /* FIXME: this is a work-around for a bug in QEMU enabling
976      * too early vrings. When protocol features are enabled,
977      * we have to respect * VHOST_USER_SET_VRING_ENABLE request. */
978     dev->ready = 0;
979 
980     if (dev->vq[index].call_fd != -1) {
981         close(dev->vq[index].call_fd);
982         dispatcher_remove(&dev->dispatcher, dev->vq[index].call_fd);
983         dev->vq[index].call_fd = -1;
984     }
985     if (dev->vq[index].kick_fd != -1) {
986         close(dev->vq[index].kick_fd);
987         dispatcher_remove(&dev->dispatcher, dev->vq[index].kick_fd);
988         dev->vq[index].kick_fd = -1;
989     }
990 
991     /* Reply */
992     return 1;
993 }
994 
995 static int
996 vubr_set_vring_kick_exec(VubrDev *dev, VhostUserMsg *vmsg)
997 {
998     uint64_t u64_arg = vmsg->payload.u64;
999     int index = u64_arg & VHOST_USER_VRING_IDX_MASK;
1000 
1001     DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
1002 
1003     assert((u64_arg & VHOST_USER_VRING_NOFD_MASK) == 0);
1004     assert(vmsg->fd_num == 1);
1005 
1006     if (dev->vq[index].kick_fd != -1) {
1007         close(dev->vq[index].kick_fd);
1008         dispatcher_remove(&dev->dispatcher, dev->vq[index].kick_fd);
1009     }
1010     dev->vq[index].kick_fd = vmsg->fds[0];
1011     DPRINT("Got kick_fd: %d for vq: %d\n", vmsg->fds[0], index);
1012 
1013     if (index % 2 == 1) {
1014         /* TX queue. */
1015         dispatcher_add(&dev->dispatcher, dev->vq[index].kick_fd,
1016                        dev, vubr_kick_cb);
1017 
1018         DPRINT("Waiting for kicks on fd: %d for vq: %d\n",
1019                dev->vq[index].kick_fd, index);
1020     }
1021     /* We temporarily use this hack to determine that both TX and RX
1022      * queues are set up and ready for processing.
1023      * FIXME: we need to rely in VHOST_USER_SET_VRING_ENABLE and
1024      * actual kicks. */
1025     if (dev->vq[0].kick_fd != -1 &&
1026         dev->vq[1].kick_fd != -1) {
1027         dev->ready = 1;
1028         DPRINT("vhost-user-bridge is ready for processing queues.\n");
1029     }
1030     return 0;
1031 
1032 }
1033 
1034 static int
1035 vubr_set_vring_call_exec(VubrDev *dev, VhostUserMsg *vmsg)
1036 {
1037     uint64_t u64_arg = vmsg->payload.u64;
1038     int index = u64_arg & VHOST_USER_VRING_IDX_MASK;
1039 
1040     DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
1041     assert((u64_arg & VHOST_USER_VRING_NOFD_MASK) == 0);
1042     assert(vmsg->fd_num == 1);
1043 
1044     if (dev->vq[index].call_fd != -1) {
1045         close(dev->vq[index].call_fd);
1046         dispatcher_remove(&dev->dispatcher, dev->vq[index].call_fd);
1047     }
1048     dev->vq[index].call_fd = vmsg->fds[0];
1049     DPRINT("Got call_fd: %d for vq: %d\n", vmsg->fds[0], index);
1050 
1051     return 0;
1052 }
1053 
1054 static int
1055 vubr_set_vring_err_exec(VubrDev *dev, VhostUserMsg *vmsg)
1056 {
1057     DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
1058     return 0;
1059 }
1060 
1061 static int
1062 vubr_get_protocol_features_exec(VubrDev *dev, VhostUserMsg *vmsg)
1063 {
1064     vmsg->payload.u64 = 1ULL << VHOST_USER_PROTOCOL_F_LOG_SHMFD;
1065     DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
1066     vmsg->size = sizeof(vmsg->payload.u64);
1067 
1068     /* Reply */
1069     return 1;
1070 }
1071 
1072 static int
1073 vubr_set_protocol_features_exec(VubrDev *dev, VhostUserMsg *vmsg)
1074 {
1075     /* FIXME: unimplented */
1076     DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
1077     return 0;
1078 }
1079 
1080 static int
1081 vubr_get_queue_num_exec(VubrDev *dev, VhostUserMsg *vmsg)
1082 {
1083     DPRINT("Function %s() not implemented yet.\n", __func__);
1084     return 0;
1085 }
1086 
1087 static int
1088 vubr_set_vring_enable_exec(VubrDev *dev, VhostUserMsg *vmsg)
1089 {
1090     unsigned int index = vmsg->payload.state.index;
1091     unsigned int enable = vmsg->payload.state.num;
1092 
1093     DPRINT("State.index: %d\n", index);
1094     DPRINT("State.enable:   %d\n", enable);
1095     dev->vq[index].enable = enable;
1096     return 0;
1097 }
1098 
1099 static int
1100 vubr_send_rarp_exec(VubrDev *dev, VhostUserMsg *vmsg)
1101 {
1102     DPRINT("Function %s() not implemented yet.\n", __func__);
1103     return 0;
1104 }
1105 
1106 static int
1107 vubr_execute_request(VubrDev *dev, VhostUserMsg *vmsg)
1108 {
1109     /* Print out generic part of the request. */
1110     DPRINT(
1111            "==================   Vhost user message from QEMU   ==================\n");
1112     DPRINT("Request: %s (%d)\n", vubr_request_str[vmsg->request],
1113            vmsg->request);
1114     DPRINT("Flags:   0x%x\n", vmsg->flags);
1115     DPRINT("Size:    %d\n", vmsg->size);
1116 
1117     if (vmsg->fd_num) {
1118         int i;
1119         DPRINT("Fds:");
1120         for (i = 0; i < vmsg->fd_num; i++) {
1121             DPRINT(" %d", vmsg->fds[i]);
1122         }
1123         DPRINT("\n");
1124     }
1125 
1126     switch (vmsg->request) {
1127     case VHOST_USER_NONE:
1128         return vubr_none_exec(dev, vmsg);
1129     case VHOST_USER_GET_FEATURES:
1130         return vubr_get_features_exec(dev, vmsg);
1131     case VHOST_USER_SET_FEATURES:
1132         return vubr_set_features_exec(dev, vmsg);
1133     case VHOST_USER_SET_OWNER:
1134         return vubr_set_owner_exec(dev, vmsg);
1135     case VHOST_USER_RESET_OWNER:
1136         return vubr_reset_device_exec(dev, vmsg);
1137     case VHOST_USER_SET_MEM_TABLE:
1138         return vubr_set_mem_table_exec(dev, vmsg);
1139     case VHOST_USER_SET_LOG_BASE:
1140         return vubr_set_log_base_exec(dev, vmsg);
1141     case VHOST_USER_SET_LOG_FD:
1142         return vubr_set_log_fd_exec(dev, vmsg);
1143     case VHOST_USER_SET_VRING_NUM:
1144         return vubr_set_vring_num_exec(dev, vmsg);
1145     case VHOST_USER_SET_VRING_ADDR:
1146         return vubr_set_vring_addr_exec(dev, vmsg);
1147     case VHOST_USER_SET_VRING_BASE:
1148         return vubr_set_vring_base_exec(dev, vmsg);
1149     case VHOST_USER_GET_VRING_BASE:
1150         return vubr_get_vring_base_exec(dev, vmsg);
1151     case VHOST_USER_SET_VRING_KICK:
1152         return vubr_set_vring_kick_exec(dev, vmsg);
1153     case VHOST_USER_SET_VRING_CALL:
1154         return vubr_set_vring_call_exec(dev, vmsg);
1155     case VHOST_USER_SET_VRING_ERR:
1156         return vubr_set_vring_err_exec(dev, vmsg);
1157     case VHOST_USER_GET_PROTOCOL_FEATURES:
1158         return vubr_get_protocol_features_exec(dev, vmsg);
1159     case VHOST_USER_SET_PROTOCOL_FEATURES:
1160         return vubr_set_protocol_features_exec(dev, vmsg);
1161     case VHOST_USER_GET_QUEUE_NUM:
1162         return vubr_get_queue_num_exec(dev, vmsg);
1163     case VHOST_USER_SET_VRING_ENABLE:
1164         return vubr_set_vring_enable_exec(dev, vmsg);
1165     case VHOST_USER_SEND_RARP:
1166         return vubr_send_rarp_exec(dev, vmsg);
1167 
1168     case VHOST_USER_MAX:
1169         assert(vmsg->request != VHOST_USER_MAX);
1170     }
1171     return 0;
1172 }
1173 
1174 static void
1175 vubr_receive_cb(int sock, void *ctx)
1176 {
1177     VubrDev *dev = (VubrDev *) ctx;
1178     VhostUserMsg vmsg;
1179     int reply_requested;
1180 
1181     vubr_message_read(sock, &vmsg);
1182     reply_requested = vubr_execute_request(dev, &vmsg);
1183     if (reply_requested) {
1184         /* Set the version in the flags when sending the reply */
1185         vmsg.flags &= ~VHOST_USER_VERSION_MASK;
1186         vmsg.flags |= VHOST_USER_VERSION;
1187         vmsg.flags |= VHOST_USER_REPLY_MASK;
1188         vubr_message_write(sock, &vmsg);
1189     }
1190 }
1191 
1192 static void
1193 vubr_accept_cb(int sock, void *ctx)
1194 {
1195     VubrDev *dev = (VubrDev *)ctx;
1196     int conn_fd;
1197     struct sockaddr_un un;
1198     socklen_t len = sizeof(un);
1199 
1200     conn_fd = accept(sock, (struct sockaddr *) &un, &len);
1201     if (conn_fd == -1) {
1202         vubr_die("accept()");
1203     }
1204     DPRINT("Got connection from remote peer on sock %d\n", conn_fd);
1205     dispatcher_add(&dev->dispatcher, conn_fd, ctx, vubr_receive_cb);
1206 }
1207 
1208 static VubrDev *
1209 vubr_new(const char *path, bool client)
1210 {
1211     VubrDev *dev = (VubrDev *) calloc(1, sizeof(VubrDev));
1212     dev->nregions = 0;
1213     int i;
1214     struct sockaddr_un un;
1215     CallbackFunc cb;
1216     size_t len;
1217 
1218     for (i = 0; i < MAX_NR_VIRTQUEUE; i++) {
1219         dev->vq[i] = (VubrVirtq) {
1220             .call_fd = -1, .kick_fd = -1,
1221             .size = 0,
1222             .last_avail_index = 0, .last_used_index = 0,
1223             .desc = 0, .avail = 0, .used = 0,
1224             .enable = 0,
1225         };
1226     }
1227 
1228     /* Init log */
1229     dev->log_call_fd = -1;
1230     dev->log_size = 0;
1231     dev->log_table = 0;
1232     dev->ready = 0;
1233     dev->features = 0;
1234 
1235     /* Get a UNIX socket. */
1236     dev->sock = socket(AF_UNIX, SOCK_STREAM, 0);
1237     if (dev->sock == -1) {
1238         vubr_die("socket");
1239     }
1240 
1241     un.sun_family = AF_UNIX;
1242     strcpy(un.sun_path, path);
1243     len = sizeof(un.sun_family) + strlen(path);
1244 
1245     if (!client) {
1246         unlink(path);
1247 
1248         if (bind(dev->sock, (struct sockaddr *) &un, len) == -1) {
1249             vubr_die("bind");
1250         }
1251 
1252         if (listen(dev->sock, 1) == -1) {
1253             vubr_die("listen");
1254         }
1255         cb = vubr_accept_cb;
1256 
1257         DPRINT("Waiting for connections on UNIX socket %s ...\n", path);
1258     } else {
1259         if (connect(dev->sock, (struct sockaddr *)&un, len) == -1) {
1260             vubr_die("connect");
1261         }
1262         cb = vubr_receive_cb;
1263     }
1264 
1265     dispatcher_init(&dev->dispatcher);
1266     dispatcher_add(&dev->dispatcher, dev->sock, (void *)dev, cb);
1267 
1268     return dev;
1269 }
1270 
1271 static void
1272 vubr_set_host(struct sockaddr_in *saddr, const char *host)
1273 {
1274     if (isdigit(host[0])) {
1275         if (!inet_aton(host, &saddr->sin_addr)) {
1276             fprintf(stderr, "inet_aton() failed.\n");
1277             exit(1);
1278         }
1279     } else {
1280         struct hostent *he = gethostbyname(host);
1281 
1282         if (!he) {
1283             fprintf(stderr, "gethostbyname() failed.\n");
1284             exit(1);
1285         }
1286         saddr->sin_addr = *(struct in_addr *)he->h_addr;
1287     }
1288 }
1289 
1290 static void
1291 vubr_backend_udp_setup(VubrDev *dev,
1292                        const char *local_host,
1293                        const char *local_port,
1294                        const char *remote_host,
1295                        const char *remote_port)
1296 {
1297     int sock;
1298     const char *r;
1299 
1300     int lport, rport;
1301 
1302     lport = strtol(local_port, (char **)&r, 0);
1303     if (r == local_port) {
1304         fprintf(stderr, "lport parsing failed.\n");
1305         exit(1);
1306     }
1307 
1308     rport = strtol(remote_port, (char **)&r, 0);
1309     if (r == remote_port) {
1310         fprintf(stderr, "rport parsing failed.\n");
1311         exit(1);
1312     }
1313 
1314     struct sockaddr_in si_local = {
1315         .sin_family = AF_INET,
1316         .sin_port = htons(lport),
1317     };
1318 
1319     vubr_set_host(&si_local, local_host);
1320 
1321     /* setup destination for sends */
1322     dev->backend_udp_dest = (struct sockaddr_in) {
1323         .sin_family = AF_INET,
1324         .sin_port = htons(rport),
1325     };
1326     vubr_set_host(&dev->backend_udp_dest, remote_host);
1327 
1328     sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
1329     if (sock == -1) {
1330         vubr_die("socket");
1331     }
1332 
1333     if (bind(sock, (struct sockaddr *)&si_local, sizeof(si_local)) == -1) {
1334         vubr_die("bind");
1335     }
1336 
1337     dev->backend_udp_sock = sock;
1338     dispatcher_add(&dev->dispatcher, sock, dev, vubr_backend_recv_cb);
1339     DPRINT("Waiting for data from udp backend on %s:%d...\n",
1340            local_host, lport);
1341 }
1342 
1343 static void
1344 vubr_run(VubrDev *dev)
1345 {
1346     while (1) {
1347         /* timeout 200ms */
1348         dispatcher_wait(&dev->dispatcher, 200000);
1349         /* Here one can try polling strategy. */
1350     }
1351 }
1352 
1353 static int
1354 vubr_parse_host_port(const char **host, const char **port, const char *buf)
1355 {
1356     char *p = strchr(buf, ':');
1357 
1358     if (!p) {
1359         return -1;
1360     }
1361     *p = '\0';
1362     *host = strdup(buf);
1363     *port = strdup(p + 1);
1364     return 0;
1365 }
1366 
1367 #define DEFAULT_UD_SOCKET "/tmp/vubr.sock"
1368 #define DEFAULT_LHOST "127.0.0.1"
1369 #define DEFAULT_LPORT "4444"
1370 #define DEFAULT_RHOST "127.0.0.1"
1371 #define DEFAULT_RPORT "5555"
1372 
1373 static const char *ud_socket_path = DEFAULT_UD_SOCKET;
1374 static const char *lhost = DEFAULT_LHOST;
1375 static const char *lport = DEFAULT_LPORT;
1376 static const char *rhost = DEFAULT_RHOST;
1377 static const char *rport = DEFAULT_RPORT;
1378 
1379 int
1380 main(int argc, char *argv[])
1381 {
1382     VubrDev *dev;
1383     int opt;
1384     bool client = false;
1385 
1386     while ((opt = getopt(argc, argv, "l:r:u:c")) != -1) {
1387 
1388         switch (opt) {
1389         case 'l':
1390             if (vubr_parse_host_port(&lhost, &lport, optarg) < 0) {
1391                 goto out;
1392             }
1393             break;
1394         case 'r':
1395             if (vubr_parse_host_port(&rhost, &rport, optarg) < 0) {
1396                 goto out;
1397             }
1398             break;
1399         case 'u':
1400             ud_socket_path = strdup(optarg);
1401             break;
1402         case 'c':
1403             client = true;
1404             break;
1405         default:
1406             goto out;
1407         }
1408     }
1409 
1410     DPRINT("ud socket: %s (%s)\n", ud_socket_path,
1411            client ? "client" : "server");
1412     DPRINT("local:     %s:%s\n", lhost, lport);
1413     DPRINT("remote:    %s:%s\n", rhost, rport);
1414 
1415     dev = vubr_new(ud_socket_path, client);
1416     if (!dev) {
1417         return 1;
1418     }
1419 
1420     vubr_backend_udp_setup(dev, lhost, lport, rhost, rport);
1421     vubr_run(dev);
1422     return 0;
1423 
1424 out:
1425     fprintf(stderr, "Usage: %s ", argv[0]);
1426     fprintf(stderr, "[-c] [-u ud_socket_path] [-l lhost:lport] [-r rhost:rport]\n");
1427     fprintf(stderr, "\t-u path to unix doman socket. default: %s\n",
1428             DEFAULT_UD_SOCKET);
1429     fprintf(stderr, "\t-l local host and port. default: %s:%s\n",
1430             DEFAULT_LHOST, DEFAULT_LPORT);
1431     fprintf(stderr, "\t-r remote host and port. default: %s:%s\n",
1432             DEFAULT_RHOST, DEFAULT_RPORT);
1433     fprintf(stderr, "\t-c client mode\n");
1434 
1435     return 1;
1436 }
1437