net/tap.c

   1 /*
   2  * QEMU System Emulator
   3  *
   4  * Copyright (c) 2003-2008 Fabrice Bellard
   5  * Copyright (c) 2009 Red Hat, Inc.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  */
  25
  26 #include "tap_int.h"
  27
  28 #include "config-host.h"
  29
  30 #include <sys/ioctl.h>
  31 #include <sys/stat.h>
  32 #include <sys/wait.h>
  33 #include <sys/socket.h>
  34 #include <net/if.h>
  35
  36 #include "net/net.h"
  37 #include "clients.h"
  38 #include "monitor/monitor.h"
  39 #include "sysemu/sysemu.h"
  40 #include "qemu-common.h"
  41 #include "qemu/error-report.h"
  42
  43 #include "net/tap.h"
  44
  45 #include "hw/vhost_net.h"
  46
  47 /* Maximum GSO packet size (64k) plus plenty of room for
  48  * the ethernet and virtio_net headers
  49  */
  50 #define TAP_BUFSIZE (4096 + 65536)
  51
  52 typedef struct TAPState {
  53     NetClientState nc;
  54     int fd;
  55     char down_script[1024];
  56     char down_script_arg[128];
  57     uint8_t buf[TAP_BUFSIZE];
  58     unsigned int read_poll : 1;
  59     unsigned int write_poll : 1;
  60     unsigned int using_vnet_hdr : 1;
  61     unsigned int has_ufo: 1;
  62     VHostNetState *vhost_net;
  63     unsigned host_vnet_hdr_len;
  64 } TAPState;
  65
  66 static int launch_script(const char *setup_script, const char *ifname, int fd);
  67
  68 static int tap_can_send(void *opaque);
  69 static void tap_send(void *opaque);
  70 static void tap_writable(void *opaque);
  71
  72 static void tap_update_fd_handler(TAPState *s)
  73 {
  74     qemu_set_fd_handler2(s->fd,
  75                          s->read_poll  ? tap_can_send : NULL,
  76                          s->read_poll  ? tap_send     : NULL,
  77                          s->write_poll ? tap_writable : NULL,
  78                          s);
  79 }
  80
  81 static void tap_read_poll(TAPState *s, int enable)
  82 {
  83     s->read_poll = !!enable;
  84     tap_update_fd_handler(s);
  85 }
  86
  87 static void tap_write_poll(TAPState *s, int enable)
  88 {
  89     s->write_poll = !!enable;
  90     tap_update_fd_handler(s);
  91 }
  92
  93 static void tap_writable(void *opaque)
  94 {
  95     TAPState *s = opaque;
  96
  97     tap_write_poll(s, 0);
  98
  99     qemu_flush_queued_packets(&s->nc);
 100 }
 101
 102 static ssize_t tap_write_packet(TAPState *s, const struct iovec *iov, int iovcnt)
 103 {
 104     ssize_t len;
 105
 106     do {
 107         len = writev(s->fd, iov, iovcnt);
 108     } while (len == -1 && errno == EINTR);
 109
 110     if (len == -1 && errno == EAGAIN) {
 111         tap_write_poll(s, 1);
 112         return 0;
 113     }
 114
 115     return len;
 116 }
 117
 118 static ssize_t tap_receive_iov(NetClientState *nc, const struct iovec *iov,
 119                                int iovcnt)
 120 {
 121     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 122     const struct iovec *iovp = iov;
 123     struct iovec iov_copy[iovcnt + 1];
 124     struct virtio_net_hdr_mrg_rxbuf hdr = { };
 125
 126     if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
 127         iov_copy[0].iov_base = &hdr;
 128         iov_copy[0].iov_len =  s->host_vnet_hdr_len;
 129         memcpy(&iov_copy[1], iov, iovcnt * sizeof(*iov));
 130         iovp = iov_copy;
 131         iovcnt++;
 132     }
 133
 134     return tap_write_packet(s, iovp, iovcnt);
 135 }
 136
 137 static ssize_t tap_receive_raw(NetClientState *nc, const uint8_t *buf, size_t size)
 138 {
 139     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 140     struct iovec iov[2];
 141     int iovcnt = 0;
 142     struct virtio_net_hdr_mrg_rxbuf hdr = { };
 143
 144     if (s->host_vnet_hdr_len) {
 145         iov[iovcnt].iov_base = &hdr;
 146         iov[iovcnt].iov_len  = s->host_vnet_hdr_len;
 147         iovcnt++;
 148     }
 149
 150     iov[iovcnt].iov_base = (char *)buf;
 151     iov[iovcnt].iov_len  = size;
 152     iovcnt++;
 153
 154     return tap_write_packet(s, iov, iovcnt);
 155 }
 156
 157 static ssize_t tap_receive(NetClientState *nc, const uint8_t *buf, size_t size)
 158 {
 159     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 160     struct iovec iov[1];
 161
 162     if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
 163         return tap_receive_raw(nc, buf, size);
 164     }
 165
 166     iov[0].iov_base = (char *)buf;
 167     iov[0].iov_len  = size;
 168
 169     return tap_write_packet(s, iov, 1);
 170 }
 171
 172 static int tap_can_send(void *opaque)
 173 {
 174     TAPState *s = opaque;
 175
 176     return qemu_can_send_packet(&s->nc);
 177 }
 178
 179 #ifndef __sun__
 180 ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen)
 181 {
 182     return read(tapfd, buf, maxlen);
 183 }
 184 #endif
 185
 186 static void tap_send_completed(NetClientState *nc, ssize_t len)
 187 {
 188     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 189     tap_read_poll(s, 1);
 190 }
 191
 192 static void tap_send(void *opaque)
 193 {
 194     TAPState *s = opaque;
 195     int size;
 196
 197     do {
 198         uint8_t *buf = s->buf;
 199
 200         size = tap_read_packet(s->fd, s->buf, sizeof(s->buf));
 201         if (size <= 0) {
 202             break;
 203         }
 204
 205         if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
 206             buf  += s->host_vnet_hdr_len;
 207             size -= s->host_vnet_hdr_len;
 208         }
 209
 210         size = qemu_send_packet_async(&s->nc, buf, size, tap_send_completed);
 211         if (size == 0) {
 212             tap_read_poll(s, 0);
 213         }
 214     } while (size > 0 && qemu_can_send_packet(&s->nc));
 215 }
 216
 217 int tap_has_ufo(NetClientState *nc)
 218 {
 219     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 220
 221     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP);
 222
 223     return s->has_ufo;
 224 }
 225
 226 int tap_has_vnet_hdr(NetClientState *nc)
 227 {
 228     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 229
 230     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP);
 231
 232     return !!s->host_vnet_hdr_len;
 233 }
 234
 235 int tap_has_vnet_hdr_len(NetClientState *nc, int len)
 236 {
 237     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 238
 239     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP);
 240
 241     return tap_probe_vnet_hdr_len(s->fd, len);
 242 }
 243
 244 void tap_set_vnet_hdr_len(NetClientState *nc, int len)
 245 {
 246     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 247
 248     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP);
 249     assert(len == sizeof(struct virtio_net_hdr_mrg_rxbuf) ||
 250            len == sizeof(struct virtio_net_hdr));
 251
 252     tap_fd_set_vnet_hdr_len(s->fd, len);
 253     s->host_vnet_hdr_len = len;
 254 }
 255
 256 void tap_using_vnet_hdr(NetClientState *nc, int using_vnet_hdr)
 257 {
 258     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 259
 260     using_vnet_hdr = using_vnet_hdr != 0;
 261
 262     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP);
 263     assert(!!s->host_vnet_hdr_len == using_vnet_hdr);
 264
 265     s->using_vnet_hdr = using_vnet_hdr;
 266 }
 267
 268 void tap_set_offload(NetClientState *nc, int csum, int tso4,
 269                      int tso6, int ecn, int ufo)
 270 {
 271     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 272     if (s->fd < 0) {
 273         return;
 274     }
 275
 276     tap_fd_set_offload(s->fd, csum, tso4, tso6, ecn, ufo);
 277 }
 278
 279 static void tap_cleanup(NetClientState *nc)
 280 {
 281     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 282
 283     if (s->vhost_net) {
 284         vhost_net_cleanup(s->vhost_net);
 285         s->vhost_net = NULL;
 286     }
 287
 288     qemu_purge_queued_packets(nc);
 289
 290     if (s->down_script[0])
 291         launch_script(s->down_script, s->down_script_arg, s->fd);
 292
 293     tap_read_poll(s, 0);
 294     tap_write_poll(s, 0);
 295     close(s->fd);
 296     s->fd = -1;
 297 }
 298
 299 static void tap_poll(NetClientState *nc, bool enable)
 300 {
 301     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 302     tap_read_poll(s, enable);
 303     tap_write_poll(s, enable);
 304 }
 305
 306 int tap_get_fd(NetClientState *nc)
 307 {
 308     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 309     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP);
 310     return s->fd;
 311 }
 312
 313 /* fd support */
 314
 315 static NetClientInfo net_tap_info = {
 316     .type = NET_CLIENT_OPTIONS_KIND_TAP,
 317     .size = sizeof(TAPState),
 318     .receive = tap_receive,
 319     .receive_raw = tap_receive_raw,
 320     .receive_iov = tap_receive_iov,
 321     .poll = tap_poll,
 322     .cleanup = tap_cleanup,
 323 };
 324
 325 static TAPState *net_tap_fd_init(NetClientState *peer,
 326                                  const char *model,
 327                                  const char *name,
 328                                  int fd,
 329                                  int vnet_hdr)
 330 {
 331     NetClientState *nc;
 332     TAPState *s;
 333
 334     nc = qemu_new_net_client(&net_tap_info, peer, model, name);
 335
 336     s = DO_UPCAST(TAPState, nc, nc);
 337
 338     s->fd = fd;
 339     s->host_vnet_hdr_len = vnet_hdr ? sizeof(struct virtio_net_hdr) : 0;
 340     s->using_vnet_hdr = 0;
 341     s->has_ufo = tap_probe_has_ufo(s->fd);
 342     tap_set_offload(&s->nc, 0, 0, 0, 0, 0);
 343     /*
 344      * Make sure host header length is set correctly in tap:
 345      * it might have been modified by another instance of qemu.
 346      */
 347     if (tap_probe_vnet_hdr_len(s->fd, s->host_vnet_hdr_len)) {
 348         tap_fd_set_vnet_hdr_len(s->fd, s->host_vnet_hdr_len);
 349     }
 350     tap_read_poll(s, 1);
 351     s->vhost_net = NULL;
 352     return s;
 353 }
 354
 355 static int launch_script(const char *setup_script, const char *ifname, int fd)
 356 {
 357     int pid, status;
 358     char *args[3];
 359     char **parg;
 360
 361     /* try to launch network script */
 362     pid = fork();
 363     if (pid == 0) {
 364         int open_max = sysconf(_SC_OPEN_MAX), i;
 365
 366         for (i = 0; i < open_max; i++) {
 367             if (i != STDIN_FILENO &&
 368                 i != STDOUT_FILENO &&
 369                 i != STDERR_FILENO &&
 370                 i != fd) {
 371                 close(i);
 372             }
 373         }
 374         parg = args;
 375         *parg++ = (char *)setup_script;
 376         *parg++ = (char *)ifname;
 377         *parg = NULL;
 378         execv(setup_script, args);
 379         _exit(1);
 380     } else if (pid > 0) {
 381         while (waitpid(pid, &status, 0) != pid) {
 382             /* loop */
 383         }
 384
 385         if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
 386             return 0;
 387         }
 388     }
 389     fprintf(stderr, "%s: could not launch network script\n", setup_script);
 390     return -1;
 391 }
 392
 393 static int recv_fd(int c)
 394 {
 395     int fd;
 396     uint8_t msgbuf[CMSG_SPACE(sizeof(fd))];
 397     struct msghdr msg = {
 398         .msg_control = msgbuf,
 399         .msg_controllen = sizeof(msgbuf),
 400     };
 401     struct cmsghdr *cmsg;
 402     struct iovec iov;
 403     uint8_t req[1];
 404     ssize_t len;
 405
 406     cmsg = CMSG_FIRSTHDR(&msg);
 407     cmsg->cmsg_level = SOL_SOCKET;
 408     cmsg->cmsg_type = SCM_RIGHTS;
 409     cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
 410     msg.msg_controllen = cmsg->cmsg_len;
 411
 412     iov.iov_base = req;
 413     iov.iov_len = sizeof(req);
 414
 415     msg.msg_iov = &iov;
 416     msg.msg_iovlen = 1;
 417
 418     len = recvmsg(c, &msg, 0);
 419     if (len > 0) {
 420         memcpy(&fd, CMSG_DATA(cmsg), sizeof(fd));
 421         return fd;
 422     }
 423
 424     return len;
 425 }
 426
 427 static int net_bridge_run_helper(const char *helper, const char *bridge)
 428 {
 429     sigset_t oldmask, mask;
 430     int pid, status;
 431     char *args[5];
 432     char **parg;
 433     int sv[2];
 434
 435     sigemptyset(&mask);
 436     sigaddset(&mask, SIGCHLD);
 437     sigprocmask(SIG_BLOCK, &mask, &oldmask);
 438
 439     if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) == -1) {
 440         return -1;
 441     }
 442
 443     /* try to launch bridge helper */
 444     pid = fork();
 445     if (pid == 0) {
 446         int open_max = sysconf(_SC_OPEN_MAX), i;
 447         char fd_buf[6+10];
 448         char br_buf[6+IFNAMSIZ] = {0};
 449         char helper_cmd[PATH_MAX + sizeof(fd_buf) + sizeof(br_buf) + 15];
 450
 451         for (i = 0; i < open_max; i++) {
 452             if (i != STDIN_FILENO &&
 453                 i != STDOUT_FILENO &&
 454                 i != STDERR_FILENO &&
 455                 i != sv[1]) {
 456                 close(i);
 457             }
 458         }
 459
 460         snprintf(fd_buf, sizeof(fd_buf), "%s%d", "--fd=", sv[1]);
 461
 462         if (strrchr(helper, ' ') || strrchr(helper, '\t')) {
 463             /* assume helper is a command */
 464
 465             if (strstr(helper, "--br=") == NULL) {
 466                 snprintf(br_buf, sizeof(br_buf), "%s%s", "--br=", bridge);
 467             }
 468
 469             snprintf(helper_cmd, sizeof(helper_cmd), "%s %s %s %s",
 470                      helper, "--use-vnet", fd_buf, br_buf);
 471
 472             parg = args;
 473             *parg++ = (char *)"sh";
 474             *parg++ = (char *)"-c";
 475             *parg++ = helper_cmd;
 476             *parg++ = NULL;
 477
 478             execv("/bin/sh", args);
 479         } else {
 480             /* assume helper is just the executable path name */
 481
 482             snprintf(br_buf, sizeof(br_buf), "%s%s", "--br=", bridge);
 483
 484             parg = args;
 485             *parg++ = (char *)helper;
 486             *parg++ = (char *)"--use-vnet";
 487             *parg++ = fd_buf;
 488             *parg++ = br_buf;
 489             *parg++ = NULL;
 490
 491             execv(helper, args);
 492         }
 493         _exit(1);
 494
 495     } else if (pid > 0) {
 496         int fd;
 497
 498         close(sv[1]);
 499
 500         do {
 501             fd = recv_fd(sv[0]);
 502         } while (fd == -1 && errno == EINTR);
 503
 504         close(sv[0]);
 505
 506         while (waitpid(pid, &status, 0) != pid) {
 507             /* loop */
 508         }
 509         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 510         if (fd < 0) {
 511             fprintf(stderr, "failed to recv file descriptor\n");
 512             return -1;
 513         }
 514
 515         if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
 516             return fd;
 517         }
 518     }
 519     fprintf(stderr, "failed to launch bridge helper\n");
 520     return -1;
 521 }
 522
 523 int net_init_bridge(const NetClientOptions *opts, const char *name,
 524                     NetClientState *peer)
 525 {
 526     const NetdevBridgeOptions *bridge;
 527     const char *helper, *br;
 528
 529     TAPState *s;
 530     int fd, vnet_hdr;
 531
 532     assert(opts->kind == NET_CLIENT_OPTIONS_KIND_BRIDGE);
 533     bridge = opts->bridge;
 534
 535     helper = bridge->has_helper ? bridge->helper : DEFAULT_BRIDGE_HELPER;
 536     br     = bridge->has_br     ? bridge->br     : DEFAULT_BRIDGE_INTERFACE;
 537
 538     fd = net_bridge_run_helper(helper, br);
 539     if (fd == -1) {
 540         return -1;
 541     }
 542
 543     fcntl(fd, F_SETFL, O_NONBLOCK);
 544
 545     vnet_hdr = tap_probe_vnet_hdr(fd);
 546
 547     s = net_tap_fd_init(peer, "bridge", name, fd, vnet_hdr);
 548     if (!s) {
 549         close(fd);
 550         return -1;
 551     }
 552
 553     snprintf(s->nc.info_str, sizeof(s->nc.info_str), "helper=%s,br=%s", helper,
 554              br);
 555
 556     return 0;
 557 }
 558
 559 static int net_tap_init(const NetdevTapOptions *tap, int *vnet_hdr,
 560                         const char *setup_script, char *ifname,
 561                         size_t ifname_sz)
 562 {
 563     int fd, vnet_hdr_required;
 564
 565     if (tap->has_ifname) {
 566         pstrcpy(ifname, ifname_sz, tap->ifname);
 567     } else {
 568         assert(ifname_sz > 0);
 569         ifname[0] = '\0';
 570     }
 571
 572     if (tap->has_vnet_hdr) {
 573         *vnet_hdr = tap->vnet_hdr;
 574         vnet_hdr_required = *vnet_hdr;
 575     } else {
 576         *vnet_hdr = 1;
 577         vnet_hdr_required = 0;
 578     }
 579
 580     TFR(fd = tap_open(ifname, ifname_sz, vnet_hdr, vnet_hdr_required));
 581     if (fd < 0) {
 582         return -1;
 583     }
 584
 585     if (setup_script &&
 586         setup_script[0] != '\0' &&
 587         strcmp(setup_script, "no") != 0 &&
 588         launch_script(setup_script, ifname, fd)) {
 589         close(fd);
 590         return -1;
 591     }
 592
 593     return fd;
 594 }
 595
 596 int net_init_tap(const NetClientOptions *opts, const char *name,
 597                  NetClientState *peer)
 598 {
 599     const NetdevTapOptions *tap;
 600
 601     int fd, vnet_hdr = 0;
 602     const char *model;
 603     TAPState *s;
 604
 605     /* for the no-fd, no-helper case */
 606     const char *script = NULL; /* suppress wrong "uninit'd use" gcc warning */
 607     char ifname[128];
 608
 609     assert(opts->kind == NET_CLIENT_OPTIONS_KIND_TAP);
 610     tap = opts->tap;
 611
 612     if (tap->has_fd) {
 613         if (tap->has_ifname || tap->has_script || tap->has_downscript ||
 614             tap->has_vnet_hdr || tap->has_helper) {
 615             error_report("ifname=, script=, downscript=, vnet_hdr=, "
 616                          "and helper= are invalid with fd=");
 617             return -1;
 618         }
 619
 620         fd = monitor_handle_fd_param(cur_mon, tap->fd);
 621         if (fd == -1) {
 622             return -1;
 623         }
 624
 625         fcntl(fd, F_SETFL, O_NONBLOCK);
 626
 627         vnet_hdr = tap_probe_vnet_hdr(fd);
 628
 629         model = "tap";
 630
 631     } else if (tap->has_helper) {
 632         if (tap->has_ifname || tap->has_script || tap->has_downscript ||
 633             tap->has_vnet_hdr) {
 634             error_report("ifname=, script=, downscript=, and vnet_hdr= "
 635                          "are invalid with helper=");
 636             return -1;
 637         }
 638
 639         fd = net_bridge_run_helper(tap->helper, DEFAULT_BRIDGE_INTERFACE);
 640         if (fd == -1) {
 641             return -1;
 642         }
 643
 644         fcntl(fd, F_SETFL, O_NONBLOCK);
 645
 646         vnet_hdr = tap_probe_vnet_hdr(fd);
 647
 648         model = "bridge";
 649
 650     } else {
 651         script = tap->has_script ? tap->script : DEFAULT_NETWORK_SCRIPT;
 652         fd = net_tap_init(tap, &vnet_hdr, script, ifname, sizeof ifname);
 653         if (fd == -1) {
 654             return -1;
 655         }
 656
 657         model = "tap";
 658     }
 659
 660     s = net_tap_fd_init(peer, model, name, fd, vnet_hdr);
 661     if (!s) {
 662         close(fd);
 663         return -1;
 664     }
 665
 666     if (tap_set_sndbuf(s->fd, tap) < 0) {
 667         return -1;
 668     }
 669
 670     if (tap->has_fd) {
 671         snprintf(s->nc.info_str, sizeof(s->nc.info_str), "fd=%d", fd);
 672     } else if (tap->has_helper) {
 673         snprintf(s->nc.info_str, sizeof(s->nc.info_str), "helper=%s",
 674                  tap->helper);
 675     } else {
 676         const char *downscript;
 677
 678         downscript = tap->has_downscript ? tap->downscript :
 679                                            DEFAULT_NETWORK_DOWN_SCRIPT;
 680
 681         snprintf(s->nc.info_str, sizeof(s->nc.info_str),
 682                  "ifname=%s,script=%s,downscript=%s", ifname, script,
 683                  downscript);
 684
 685         if (strcmp(downscript, "no") != 0) {
 686             snprintf(s->down_script, sizeof(s->down_script), "%s", downscript);
 687             snprintf(s->down_script_arg, sizeof(s->down_script_arg), "%s", ifname);
 688         }
 689     }
 690
 691     if (tap->has_vhost ? tap->vhost :
 692         tap->has_vhostfd || (tap->has_vhostforce && tap->vhostforce)) {
 693         int vhostfd;
 694
 695         if (tap->has_vhostfd) {
 696             vhostfd = monitor_handle_fd_param(cur_mon, tap->vhostfd);
 697             if (vhostfd == -1) {
 698                 return -1;
 699             }
 700         } else {
 701             vhostfd = -1;
 702         }
 703
 704         s->vhost_net = vhost_net_init(&s->nc, vhostfd,
 705                                       tap->has_vhostforce && tap->vhostforce);
 706         if (!s->vhost_net) {
 707             error_report("vhost-net requested but could not be initialized");
 708             return -1;
 709         }
 710     } else if (tap->has_vhostfd) {
 711         error_report("vhostfd= is not valid without vhost");
 712         return -1;
 713     }
 714
 715     return 0;
 716 }
 717
 718 VHostNetState *tap_get_vhost_net(NetClientState *nc)
 719 {
 720     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 721     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP);
 722     return s->vhost_net;
 723 }