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