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 "qemu/osdep.h"
  27 #include "tap_int.h"
  28
  29
  30 #include <sys/ioctl.h>
  31 #include <sys/wait.h>
  32 #include <sys/socket.h>
  33 #include <net/if.h>
  34
  35 #include "net/eth.h"
  36 #include "net/net.h"
  37 #include "clients.h"
  38 #include "monitor/monitor.h"
  39 #include "sysemu/sysemu.h"
  40 #include "qapi/error.h"
  41 #include "qemu/cutils.h"
  42 #include "qemu/error-report.h"
  43 #include "qemu/main-loop.h"
  44 #include "qemu/sockets.h"
  45
  46 #include "net/tap.h"
  47
  48 #include "net/vhost_net.h"
  49
  50 typedef struct TAPState {
  51     NetClientState nc;
  52     int fd;
  53     char down_script[1024];
  54     char down_script_arg[128];
  55     uint8_t buf[NET_BUFSIZE];
  56     bool read_poll;
  57     bool write_poll;
  58     bool using_vnet_hdr;
  59     bool has_ufo;
  60     bool has_uso;
  61     bool enabled;
  62     VHostNetState *vhost_net;
  63     unsigned host_vnet_hdr_len;
  64     Notifier exit;
  65 } TAPState;
  66
  67 static void launch_script(const char *setup_script, const char *ifname,
  68                           int fd, Error **errp);
  69
  70 static void tap_send(void *opaque);
  71 static void tap_writable(void *opaque);
  72
  73 static void tap_update_fd_handler(TAPState *s)
  74 {
  75     qemu_set_fd_handler(s->fd,
  76                         s->read_poll && s->enabled ? tap_send : NULL,
  77                         s->write_poll && s->enabled ? tap_writable : NULL,
  78                         s);
  79 }
  80
  81 static void tap_read_poll(TAPState *s, bool enable)
  82 {
  83     s->read_poll = enable;
  84     tap_update_fd_handler(s);
  85 }
  86
  87 static void tap_write_poll(TAPState *s, bool 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, false);
  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     len = RETRY_ON_EINTR(writev(s->fd, iov, iovcnt));
 107
 108     if (len == -1 && errno == EAGAIN) {
 109         tap_write_poll(s, true);
 110         return 0;
 111     }
 112
 113     return len;
 114 }
 115
 116 static ssize_t tap_receive_iov(NetClientState *nc, const struct iovec *iov,
 117                                int iovcnt)
 118 {
 119     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 120     const struct iovec *iovp = iov;
 121     g_autofree struct iovec *iov_copy = NULL;
 122     struct virtio_net_hdr_mrg_rxbuf hdr = { };
 123
 124     if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
 125         iov_copy = g_new(struct iovec, iovcnt + 1);
 126         iov_copy[0].iov_base = &hdr;
 127         iov_copy[0].iov_len =  s->host_vnet_hdr_len;
 128         memcpy(&iov_copy[1], iov, iovcnt * sizeof(*iov));
 129         iovp = iov_copy;
 130         iovcnt++;
 131     }
 132
 133     return tap_write_packet(s, iovp, iovcnt);
 134 }
 135
 136 static ssize_t tap_receive_raw(NetClientState *nc, const uint8_t *buf, size_t size)
 137 {
 138     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 139     struct iovec iov[2];
 140     int iovcnt = 0;
 141     struct virtio_net_hdr_mrg_rxbuf hdr = { };
 142
 143     if (s->host_vnet_hdr_len) {
 144         iov[iovcnt].iov_base = &hdr;
 145         iov[iovcnt].iov_len  = s->host_vnet_hdr_len;
 146         iovcnt++;
 147     }
 148
 149     iov[iovcnt].iov_base = (char *)buf;
 150     iov[iovcnt].iov_len  = size;
 151     iovcnt++;
 152
 153     return tap_write_packet(s, iov, iovcnt);
 154 }
 155
 156 static ssize_t tap_receive(NetClientState *nc, const uint8_t *buf, size_t size)
 157 {
 158     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 159     struct iovec iov[1];
 160
 161     if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
 162         return tap_receive_raw(nc, buf, size);
 163     }
 164
 165     iov[0].iov_base = (char *)buf;
 166     iov[0].iov_len  = size;
 167
 168     return tap_write_packet(s, iov, 1);
 169 }
 170
 171 #ifndef __sun__
 172 ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen)
 173 {
 174     return read(tapfd, buf, maxlen);
 175 }
 176 #endif
 177
 178 static void tap_send_completed(NetClientState *nc, ssize_t len)
 179 {
 180     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 181     tap_read_poll(s, true);
 182 }
 183
 184 static void tap_send(void *opaque)
 185 {
 186     TAPState *s = opaque;
 187     int size;
 188     int packets = 0;
 189
 190     while (true) {
 191         uint8_t *buf = s->buf;
 192         uint8_t min_pkt[ETH_ZLEN];
 193         size_t min_pktsz = sizeof(min_pkt);
 194
 195         size = tap_read_packet(s->fd, s->buf, sizeof(s->buf));
 196         if (size <= 0) {
 197             break;
 198         }
 199
 200         if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
 201             buf  += s->host_vnet_hdr_len;
 202             size -= s->host_vnet_hdr_len;
 203         }
 204
 205         if (net_peer_needs_padding(&s->nc)) {
 206             if (eth_pad_short_frame(min_pkt, &min_pktsz, buf, size)) {
 207                 buf = min_pkt;
 208                 size = min_pktsz;
 209             }
 210         }
 211
 212         size = qemu_send_packet_async(&s->nc, buf, size, tap_send_completed);
 213         if (size == 0) {
 214             tap_read_poll(s, false);
 215             break;
 216         } else if (size < 0) {
 217             break;
 218         }
 219
 220         /*
 221          * When the host keeps receiving more packets while tap_send() is
 222          * running we can hog the BQL.  Limit the number of
 223          * packets that are processed per tap_send() callback to prevent
 224          * stalling the guest.
 225          */
 226         packets++;
 227         if (packets >= 50) {
 228             break;
 229         }
 230     }
 231 }
 232
 233 static bool tap_has_ufo(NetClientState *nc)
 234 {
 235     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 236
 237     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 238
 239     return s->has_ufo;
 240 }
 241
 242 static bool tap_has_uso(NetClientState *nc)
 243 {
 244     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 245
 246     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 247
 248     return s->has_uso;
 249 }
 250
 251 static bool tap_has_vnet_hdr(NetClientState *nc)
 252 {
 253     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 254
 255     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 256
 257     return !!s->host_vnet_hdr_len;
 258 }
 259
 260 static bool tap_has_vnet_hdr_len(NetClientState *nc, int len)
 261 {
 262     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 263
 264     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 265
 266     return !!tap_probe_vnet_hdr_len(s->fd, len);
 267 }
 268
 269 static int tap_get_vnet_hdr_len(NetClientState *nc)
 270 {
 271     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 272
 273     return s->host_vnet_hdr_len;
 274 }
 275
 276 static void tap_set_vnet_hdr_len(NetClientState *nc, int len)
 277 {
 278     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 279
 280     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 281     assert(len == sizeof(struct virtio_net_hdr_mrg_rxbuf) ||
 282            len == sizeof(struct virtio_net_hdr) ||
 283            len == sizeof(struct virtio_net_hdr_v1_hash));
 284
 285     tap_fd_set_vnet_hdr_len(s->fd, len);
 286     s->host_vnet_hdr_len = len;
 287 }
 288
 289 static bool tap_get_using_vnet_hdr(NetClientState *nc)
 290 {
 291     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 292
 293     return s->using_vnet_hdr;
 294 }
 295
 296 static void tap_using_vnet_hdr(NetClientState *nc, bool using_vnet_hdr)
 297 {
 298     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 299
 300     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 301     assert(!!s->host_vnet_hdr_len == using_vnet_hdr);
 302
 303     s->using_vnet_hdr = using_vnet_hdr;
 304 }
 305
 306 static int tap_set_vnet_le(NetClientState *nc, bool is_le)
 307 {
 308     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 309
 310     return tap_fd_set_vnet_le(s->fd, is_le);
 311 }
 312
 313 static int tap_set_vnet_be(NetClientState *nc, bool is_be)
 314 {
 315     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 316
 317     return tap_fd_set_vnet_be(s->fd, is_be);
 318 }
 319
 320 static void tap_set_offload(NetClientState *nc, int csum, int tso4,
 321                      int tso6, int ecn, int ufo, int uso4, int uso6)
 322 {
 323     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 324     if (s->fd < 0) {
 325         return;
 326     }
 327
 328     tap_fd_set_offload(s->fd, csum, tso4, tso6, ecn, ufo, uso4, uso6);
 329 }
 330
 331 static void tap_exit_notify(Notifier *notifier, void *data)
 332 {
 333     TAPState *s = container_of(notifier, TAPState, exit);
 334     Error *err = NULL;
 335
 336     if (s->down_script[0]) {
 337         launch_script(s->down_script, s->down_script_arg, s->fd, &err);
 338         if (err) {
 339             error_report_err(err);
 340         }
 341     }
 342 }
 343
 344 static void tap_cleanup(NetClientState *nc)
 345 {
 346     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 347
 348     if (s->vhost_net) {
 349         vhost_net_cleanup(s->vhost_net);
 350         g_free(s->vhost_net);
 351         s->vhost_net = NULL;
 352     }
 353
 354     qemu_purge_queued_packets(nc);
 355
 356     tap_exit_notify(&s->exit, NULL);
 357     qemu_remove_exit_notifier(&s->exit);
 358
 359     tap_read_poll(s, false);
 360     tap_write_poll(s, false);
 361     close(s->fd);
 362     s->fd = -1;
 363 }
 364
 365 static void tap_poll(NetClientState *nc, bool enable)
 366 {
 367     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 368     tap_read_poll(s, enable);
 369     tap_write_poll(s, enable);
 370 }
 371
 372 static bool tap_set_steering_ebpf(NetClientState *nc, int prog_fd)
 373 {
 374     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 375     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 376
 377     return tap_fd_set_steering_ebpf(s->fd, prog_fd) == 0;
 378 }
 379
 380 int tap_get_fd(NetClientState *nc)
 381 {
 382     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 383     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 384     return s->fd;
 385 }
 386
 387 /* fd support */
 388
 389 static NetClientInfo net_tap_info = {
 390     .type = NET_CLIENT_DRIVER_TAP,
 391     .size = sizeof(TAPState),
 392     .receive = tap_receive,
 393     .receive_raw = tap_receive_raw,
 394     .receive_iov = tap_receive_iov,
 395     .poll = tap_poll,
 396     .cleanup = tap_cleanup,
 397     .has_ufo = tap_has_ufo,
 398     .has_uso = tap_has_uso,
 399     .has_vnet_hdr = tap_has_vnet_hdr,
 400     .has_vnet_hdr_len = tap_has_vnet_hdr_len,
 401     .get_using_vnet_hdr = tap_get_using_vnet_hdr,
 402     .using_vnet_hdr = tap_using_vnet_hdr,
 403     .set_offload = tap_set_offload,
 404     .get_vnet_hdr_len = tap_get_vnet_hdr_len,
 405     .set_vnet_hdr_len = tap_set_vnet_hdr_len,
 406     .set_vnet_le = tap_set_vnet_le,
 407     .set_vnet_be = tap_set_vnet_be,
 408     .set_steering_ebpf = tap_set_steering_ebpf,
 409 };
 410
 411 static TAPState *net_tap_fd_init(NetClientState *peer,
 412                                  const char *model,
 413                                  const char *name,
 414                                  int fd,
 415                                  int vnet_hdr)
 416 {
 417     NetClientState *nc;
 418     TAPState *s;
 419
 420     nc = qemu_new_net_client(&net_tap_info, peer, model, name);
 421
 422     s = DO_UPCAST(TAPState, nc, nc);
 423
 424     s->fd = fd;
 425     s->host_vnet_hdr_len = vnet_hdr ? sizeof(struct virtio_net_hdr) : 0;
 426     s->using_vnet_hdr = false;
 427     s->has_ufo = tap_probe_has_ufo(s->fd);
 428     s->has_uso = tap_probe_has_uso(s->fd);
 429     s->enabled = true;
 430     tap_set_offload(&s->nc, 0, 0, 0, 0, 0, 0, 0);
 431     /*
 432      * Make sure host header length is set correctly in tap:
 433      * it might have been modified by another instance of qemu.
 434      */
 435     if (tap_probe_vnet_hdr_len(s->fd, s->host_vnet_hdr_len)) {
 436         tap_fd_set_vnet_hdr_len(s->fd, s->host_vnet_hdr_len);
 437     }
 438     tap_read_poll(s, true);
 439     s->vhost_net = NULL;
 440
 441     s->exit.notify = tap_exit_notify;
 442     qemu_add_exit_notifier(&s->exit);
 443
 444     return s;
 445 }
 446
 447 static void launch_script(const char *setup_script, const char *ifname,
 448                           int fd, Error **errp)
 449 {
 450     int pid, status;
 451     char *args[3];
 452     char **parg;
 453
 454     /* try to launch network script */
 455     pid = fork();
 456     if (pid < 0) {
 457         error_setg_errno(errp, errno, "could not launch network script %s",
 458                          setup_script);
 459         return;
 460     }
 461     if (pid == 0) {
 462         int open_max = sysconf(_SC_OPEN_MAX), i;
 463
 464         for (i = 3; i < open_max; i++) {
 465             if (i != fd) {
 466                 close(i);
 467             }
 468         }
 469         parg = args;
 470         *parg++ = (char *)setup_script;
 471         *parg++ = (char *)ifname;
 472         *parg = NULL;
 473         execv(setup_script, args);
 474         _exit(1);
 475     } else {
 476         while (waitpid(pid, &status, 0) != pid) {
 477             /* loop */
 478         }
 479
 480         if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
 481             return;
 482         }
 483         error_setg(errp, "network script %s failed with status %d",
 484                    setup_script, status);
 485     }
 486 }
 487
 488 static int recv_fd(int c)
 489 {
 490     int fd;
 491     uint8_t msgbuf[CMSG_SPACE(sizeof(fd))];
 492     struct msghdr msg = {
 493         .msg_control = msgbuf,
 494         .msg_controllen = sizeof(msgbuf),
 495     };
 496     struct cmsghdr *cmsg;
 497     struct iovec iov;
 498     uint8_t req[1];
 499     ssize_t len;
 500
 501     cmsg = CMSG_FIRSTHDR(&msg);
 502     cmsg->cmsg_level = SOL_SOCKET;
 503     cmsg->cmsg_type = SCM_RIGHTS;
 504     cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
 505     msg.msg_controllen = cmsg->cmsg_len;
 506
 507     iov.iov_base = req;
 508     iov.iov_len = sizeof(req);
 509
 510     msg.msg_iov = &iov;
 511     msg.msg_iovlen = 1;
 512
 513     len = recvmsg(c, &msg, 0);
 514     if (len > 0) {
 515         memcpy(&fd, CMSG_DATA(cmsg), sizeof(fd));
 516         return fd;
 517     }
 518
 519     return len;
 520 }
 521
 522 static int net_bridge_run_helper(const char *helper, const char *bridge,
 523                                  Error **errp)
 524 {
 525     sigset_t oldmask, mask;
 526     g_autofree char *default_helper = NULL;
 527     int pid, status;
 528     char *args[5];
 529     char **parg;
 530     int sv[2];
 531
 532     sigemptyset(&mask);
 533     sigaddset(&mask, SIGCHLD);
 534     sigprocmask(SIG_BLOCK, &mask, &oldmask);
 535
 536     if (!helper) {
 537         helper = default_helper = get_relocated_path(DEFAULT_BRIDGE_HELPER);
 538     }
 539
 540     if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) == -1) {
 541         error_setg_errno(errp, errno, "socketpair() failed");
 542         return -1;
 543     }
 544
 545     /* try to launch bridge helper */
 546     pid = fork();
 547     if (pid < 0) {
 548         error_setg_errno(errp, errno, "Can't fork bridge helper");
 549         return -1;
 550     }
 551     if (pid == 0) {
 552         int open_max = sysconf(_SC_OPEN_MAX), i;
 553         char *fd_buf = NULL;
 554         char *br_buf = NULL;
 555         char *helper_cmd = NULL;
 556
 557         for (i = 3; i < open_max; i++) {
 558             if (i != sv[1]) {
 559                 close(i);
 560             }
 561         }
 562
 563         fd_buf = g_strdup_printf("%s%d", "--fd=", sv[1]);
 564
 565         if (strrchr(helper, ' ') || strrchr(helper, '\t')) {
 566             /* assume helper is a command */
 567
 568             if (strstr(helper, "--br=") == NULL) {
 569                 br_buf = g_strdup_printf("%s%s", "--br=", bridge);
 570             }
 571
 572             helper_cmd = g_strdup_printf("%s %s %s %s", helper,
 573                             "--use-vnet", fd_buf, br_buf ? br_buf : "");
 574
 575             parg = args;
 576             *parg++ = (char *)"sh";
 577             *parg++ = (char *)"-c";
 578             *parg++ = helper_cmd;
 579             *parg++ = NULL;
 580
 581             execv("/bin/sh", args);
 582             g_free(helper_cmd);
 583         } else {
 584             /* assume helper is just the executable path name */
 585
 586             br_buf = g_strdup_printf("%s%s", "--br=", bridge);
 587
 588             parg = args;
 589             *parg++ = (char *)helper;
 590             *parg++ = (char *)"--use-vnet";
 591             *parg++ = fd_buf;
 592             *parg++ = br_buf;
 593             *parg++ = NULL;
 594
 595             execv(helper, args);
 596         }
 597         g_free(fd_buf);
 598         g_free(br_buf);
 599         _exit(1);
 600
 601     } else {
 602         int fd;
 603         int saved_errno;
 604
 605         close(sv[1]);
 606
 607         fd = RETRY_ON_EINTR(recv_fd(sv[0]));
 608         saved_errno = errno;
 609
 610         close(sv[0]);
 611
 612         while (waitpid(pid, &status, 0) != pid) {
 613             /* loop */
 614         }
 615         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 616         if (fd < 0) {
 617             error_setg_errno(errp, saved_errno,
 618                              "failed to recv file descriptor");
 619             return -1;
 620         }
 621         if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 622             error_setg(errp, "bridge helper failed");
 623             return -1;
 624         }
 625         return fd;
 626     }
 627 }
 628
 629 int net_init_bridge(const Netdev *netdev, const char *name,
 630                     NetClientState *peer, Error **errp)
 631 {
 632     const NetdevBridgeOptions *bridge;
 633     const char *helper, *br;
 634     TAPState *s;
 635     int fd, vnet_hdr;
 636
 637     assert(netdev->type == NET_CLIENT_DRIVER_BRIDGE);
 638     bridge = &netdev->u.bridge;
 639     helper = bridge->helper;
 640     br     = bridge->br ?: DEFAULT_BRIDGE_INTERFACE;
 641
 642     fd = net_bridge_run_helper(helper, br, errp);
 643     if (fd == -1) {
 644         return -1;
 645     }
 646
 647     if (!g_unix_set_fd_nonblocking(fd, true, NULL)) {
 648         error_setg_errno(errp, errno, "Failed to set FD nonblocking");
 649         return -1;
 650     }
 651     vnet_hdr = tap_probe_vnet_hdr(fd, errp);
 652     if (vnet_hdr < 0) {
 653         close(fd);
 654         return -1;
 655     }
 656     s = net_tap_fd_init(peer, "bridge", name, fd, vnet_hdr);
 657
 658     qemu_set_info_str(&s->nc, "helper=%s,br=%s", helper, br);
 659
 660     return 0;
 661 }
 662
 663 static int net_tap_init(const NetdevTapOptions *tap, int *vnet_hdr,
 664                         const char *setup_script, char *ifname,
 665                         size_t ifname_sz, int mq_required, Error **errp)
 666 {
 667     Error *err = NULL;
 668     int fd, vnet_hdr_required;
 669
 670     if (tap->has_vnet_hdr) {
 671         *vnet_hdr = tap->vnet_hdr;
 672         vnet_hdr_required = *vnet_hdr;
 673     } else {
 674         *vnet_hdr = 1;
 675         vnet_hdr_required = 0;
 676     }
 677
 678     fd = RETRY_ON_EINTR(tap_open(ifname, ifname_sz, vnet_hdr, vnet_hdr_required,
 679                       mq_required, errp));
 680     if (fd < 0) {
 681         return -1;
 682     }
 683
 684     if (setup_script &&
 685         setup_script[0] != '\0' &&
 686         strcmp(setup_script, "no") != 0) {
 687         launch_script(setup_script, ifname, fd, &err);
 688         if (err) {
 689             error_propagate(errp, err);
 690             close(fd);
 691             return -1;
 692         }
 693     }
 694
 695     return fd;
 696 }
 697
 698 #define MAX_TAP_QUEUES 1024
 699
 700 static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
 701                              const char *model, const char *name,
 702                              const char *ifname, const char *script,
 703                              const char *downscript, const char *vhostfdname,
 704                              int vnet_hdr, int fd, Error **errp)
 705 {
 706     Error *err = NULL;
 707     TAPState *s = net_tap_fd_init(peer, model, name, fd, vnet_hdr);
 708     int vhostfd;
 709
 710     tap_set_sndbuf(s->fd, tap, &err);
 711     if (err) {
 712         error_propagate(errp, err);
 713         goto failed;
 714     }
 715
 716     if (tap->fd || tap->fds) {
 717         qemu_set_info_str(&s->nc, "fd=%d", fd);
 718     } else if (tap->helper) {
 719         qemu_set_info_str(&s->nc, "helper=%s", tap->helper);
 720     } else {
 721         qemu_set_info_str(&s->nc, "ifname=%s,script=%s,downscript=%s", ifname,
 722                           script, downscript);
 723
 724         if (strcmp(downscript, "no") != 0) {
 725             snprintf(s->down_script, sizeof(s->down_script), "%s", downscript);
 726             snprintf(s->down_script_arg, sizeof(s->down_script_arg),
 727                      "%s", ifname);
 728         }
 729     }
 730
 731     if (tap->has_vhost ? tap->vhost :
 732         vhostfdname || (tap->has_vhostforce && tap->vhostforce)) {
 733         VhostNetOptions options;
 734
 735         options.backend_type = VHOST_BACKEND_TYPE_KERNEL;
 736         options.net_backend = &s->nc;
 737         if (tap->has_poll_us) {
 738             options.busyloop_timeout = tap->poll_us;
 739         } else {
 740             options.busyloop_timeout = 0;
 741         }
 742
 743         if (vhostfdname) {
 744             vhostfd = monitor_fd_param(monitor_cur(), vhostfdname, &err);
 745             if (vhostfd == -1) {
 746                 error_propagate(errp, err);
 747                 goto failed;
 748             }
 749             if (!g_unix_set_fd_nonblocking(vhostfd, true, NULL)) {
 750                 error_setg_errno(errp, errno, "%s: Can't use file descriptor %d",
 751                                  name, fd);
 752                 goto failed;
 753             }
 754         } else {
 755             vhostfd = open("/dev/vhost-net", O_RDWR);
 756             if (vhostfd < 0) {
 757                 error_setg_errno(errp, errno,
 758                                  "tap: open vhost char device failed");
 759                 goto failed;
 760             }
 761             if (!g_unix_set_fd_nonblocking(vhostfd, true, NULL)) {
 762                 error_setg_errno(errp, errno, "Failed to set FD nonblocking");
 763                 goto failed;
 764             }
 765         }
 766         options.opaque = (void *)(uintptr_t)vhostfd;
 767         options.nvqs = 2;
 768
 769         s->vhost_net = vhost_net_init(&options);
 770         if (!s->vhost_net) {
 771             error_setg(errp,
 772                        "vhost-net requested but could not be initialized");
 773             goto failed;
 774         }
 775     } else if (vhostfdname) {
 776         error_setg(errp, "vhostfd(s)= is not valid without vhost");
 777         goto failed;
 778     }
 779
 780     return;
 781
 782 failed:
 783     qemu_del_net_client(&s->nc);
 784 }
 785
 786 static int get_fds(char *str, char *fds[], int max)
 787 {
 788     char *ptr = str, *this;
 789     size_t len = strlen(str);
 790     int i = 0;
 791
 792     while (i < max && ptr < str + len) {
 793         this = strchr(ptr, ':');
 794
 795         if (this == NULL) {
 796             fds[i] = g_strdup(ptr);
 797         } else {
 798             fds[i] = g_strndup(ptr, this - ptr);
 799         }
 800
 801         i++;
 802         if (this == NULL) {
 803             break;
 804         } else {
 805             ptr = this + 1;
 806         }
 807     }
 808
 809     return i;
 810 }
 811
 812 int net_init_tap(const Netdev *netdev, const char *name,
 813                  NetClientState *peer, Error **errp)
 814 {
 815     const NetdevTapOptions *tap;
 816     int fd, vnet_hdr = 0, i = 0, queues;
 817     /* for the no-fd, no-helper case */
 818     const char *script;
 819     const char *downscript;
 820     Error *err = NULL;
 821     const char *vhostfdname;
 822     char ifname[128];
 823     int ret = 0;
 824
 825     assert(netdev->type == NET_CLIENT_DRIVER_TAP);
 826     tap = &netdev->u.tap;
 827     queues = tap->has_queues ? tap->queues : 1;
 828     vhostfdname = tap->vhostfd;
 829     script = tap->script;
 830     downscript = tap->downscript;
 831
 832     /* QEMU hubs do not support multiqueue tap, in this case peer is set.
 833      * For -netdev, peer is always NULL. */
 834     if (peer && (tap->has_queues || tap->fds || tap->vhostfds)) {
 835         error_setg(errp, "Multiqueue tap cannot be used with hubs");
 836         return -1;
 837     }
 838
 839     if (tap->fd) {
 840         if (tap->ifname || tap->script || tap->downscript ||
 841             tap->has_vnet_hdr || tap->helper || tap->has_queues ||
 842             tap->fds || tap->vhostfds) {
 843             error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
 844                        "helper=, queues=, fds=, and vhostfds= "
 845                        "are invalid with fd=");
 846             return -1;
 847         }
 848
 849         fd = monitor_fd_param(monitor_cur(), tap->fd, errp);
 850         if (fd == -1) {
 851             return -1;
 852         }
 853
 854         if (!g_unix_set_fd_nonblocking(fd, true, NULL)) {
 855             error_setg_errno(errp, errno, "%s: Can't use file descriptor %d",
 856                              name, fd);
 857             close(fd);
 858             return -1;
 859         }
 860
 861         vnet_hdr = tap_probe_vnet_hdr(fd, errp);
 862         if (vnet_hdr < 0) {
 863             close(fd);
 864             return -1;
 865         }
 866
 867         net_init_tap_one(tap, peer, "tap", name, NULL,
 868                          script, downscript,
 869                          vhostfdname, vnet_hdr, fd, &err);
 870         if (err) {
 871             error_propagate(errp, err);
 872             close(fd);
 873             return -1;
 874         }
 875     } else if (tap->fds) {
 876         char **fds;
 877         char **vhost_fds;
 878         int nfds = 0, nvhosts = 0;
 879
 880         if (tap->ifname || tap->script || tap->downscript ||
 881             tap->has_vnet_hdr || tap->helper || tap->has_queues ||
 882             tap->vhostfd) {
 883             error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
 884                        "helper=, queues=, and vhostfd= "
 885                        "are invalid with fds=");
 886             return -1;
 887         }
 888
 889         fds = g_new0(char *, MAX_TAP_QUEUES);
 890         vhost_fds = g_new0(char *, MAX_TAP_QUEUES);
 891
 892         nfds = get_fds(tap->fds, fds, MAX_TAP_QUEUES);
 893         if (tap->vhostfds) {
 894             nvhosts = get_fds(tap->vhostfds, vhost_fds, MAX_TAP_QUEUES);
 895             if (nfds != nvhosts) {
 896                 error_setg(errp, "The number of fds passed does not match "
 897                            "the number of vhostfds passed");
 898                 ret = -1;
 899                 goto free_fail;
 900             }
 901         }
 902
 903         for (i = 0; i < nfds; i++) {
 904             fd = monitor_fd_param(monitor_cur(), fds[i], errp);
 905             if (fd == -1) {
 906                 ret = -1;
 907                 goto free_fail;
 908             }
 909
 910             ret = g_unix_set_fd_nonblocking(fd, true, NULL);
 911             if (!ret) {
 912                 error_setg_errno(errp, errno, "%s: Can't use file descriptor %d",
 913                                  name, fd);
 914                 goto free_fail;
 915             }
 916
 917             if (i == 0) {
 918                 vnet_hdr = tap_probe_vnet_hdr(fd, errp);
 919                 if (vnet_hdr < 0) {
 920                     ret = -1;
 921                     goto free_fail;
 922                 }
 923             } else if (vnet_hdr != tap_probe_vnet_hdr(fd, NULL)) {
 924                 error_setg(errp,
 925                            "vnet_hdr not consistent across given tap fds");
 926                 ret = -1;
 927                 goto free_fail;
 928             }
 929
 930             net_init_tap_one(tap, peer, "tap", name, ifname,
 931                              script, downscript,
 932                              tap->vhostfds ? vhost_fds[i] : NULL,
 933                              vnet_hdr, fd, &err);
 934             if (err) {
 935                 error_propagate(errp, err);
 936                 ret = -1;
 937                 goto free_fail;
 938             }
 939         }
 940
 941 free_fail:
 942         for (i = 0; i < nvhosts; i++) {
 943             g_free(vhost_fds[i]);
 944         }
 945         for (i = 0; i < nfds; i++) {
 946             g_free(fds[i]);
 947         }
 948         g_free(fds);
 949         g_free(vhost_fds);
 950         return ret;
 951     } else if (tap->helper) {
 952         if (tap->ifname || tap->script || tap->downscript ||
 953             tap->has_vnet_hdr || tap->has_queues || tap->vhostfds) {
 954             error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
 955                        "queues=, and vhostfds= are invalid with helper=");
 956             return -1;
 957         }
 958
 959         fd = net_bridge_run_helper(tap->helper,
 960                                    tap->br ?: DEFAULT_BRIDGE_INTERFACE,
 961                                    errp);
 962         if (fd == -1) {
 963             return -1;
 964         }
 965
 966         if (!g_unix_set_fd_nonblocking(fd, true, NULL)) {
 967             error_setg_errno(errp, errno, "Failed to set FD nonblocking");
 968             return -1;
 969         }
 970         vnet_hdr = tap_probe_vnet_hdr(fd, errp);
 971         if (vnet_hdr < 0) {
 972             close(fd);
 973             return -1;
 974         }
 975
 976         net_init_tap_one(tap, peer, "bridge", name, ifname,
 977                          script, downscript, vhostfdname,
 978                          vnet_hdr, fd, &err);
 979         if (err) {
 980             error_propagate(errp, err);
 981             close(fd);
 982             return -1;
 983         }
 984     } else {
 985         g_autofree char *default_script = NULL;
 986         g_autofree char *default_downscript = NULL;
 987         if (tap->vhostfds) {
 988             error_setg(errp, "vhostfds= is invalid if fds= wasn't specified");
 989             return -1;
 990         }
 991
 992         if (!script) {
 993             script = default_script = get_relocated_path(DEFAULT_NETWORK_SCRIPT);
 994         }
 995         if (!downscript) {
 996             downscript = default_downscript =
 997                                  get_relocated_path(DEFAULT_NETWORK_DOWN_SCRIPT);
 998         }
 999
1000         if (tap->ifname) {
1001             pstrcpy(ifname, sizeof ifname, tap->ifname);
1002         } else {
1003             ifname[0] = '\0';
1004         }
1005
1006         for (i = 0; i < queues; i++) {
1007             fd = net_tap_init(tap, &vnet_hdr, i >= 1 ? "no" : script,
1008                               ifname, sizeof ifname, queues > 1, errp);
1009             if (fd == -1) {
1010                 return -1;
1011             }
1012
1013             if (queues > 1 && i == 0 && !tap->ifname) {
1014                 if (tap_fd_get_ifname(fd, ifname)) {
1015                     error_setg(errp, "Fail to get ifname");
1016                     close(fd);
1017                     return -1;
1018                 }
1019             }
1020
1021             net_init_tap_one(tap, peer, "tap", name, ifname,
1022                              i >= 1 ? "no" : script,
1023                              i >= 1 ? "no" : downscript,
1024                              vhostfdname, vnet_hdr, fd, &err);
1025             if (err) {
1026                 error_propagate(errp, err);
1027                 close(fd);
1028                 return -1;
1029             }
1030         }
1031     }
1032
1033     return 0;
1034 }
1035
1036 VHostNetState *tap_get_vhost_net(NetClientState *nc)
1037 {
1038     TAPState *s = DO_UPCAST(TAPState, nc, nc);
1039     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
1040     return s->vhost_net;
1041 }
1042
1043 int tap_enable(NetClientState *nc)
1044 {
1045     TAPState *s = DO_UPCAST(TAPState, nc, nc);
1046     int ret;
1047
1048     if (s->enabled) {
1049         return 0;
1050     } else {
1051         ret = tap_fd_enable(s->fd);
1052         if (ret == 0) {
1053             s->enabled = true;
1054             tap_update_fd_handler(s);
1055         }
1056         return ret;
1057     }
1058 }
1059
1060 int tap_disable(NetClientState *nc)
1061 {
1062     TAPState *s = DO_UPCAST(TAPState, nc, nc);
1063     int ret;
1064
1065     if (s->enabled == 0) {
1066         return 0;
1067     } else {
1068         ret = tap_fd_disable(s->fd);
1069         if (ret == 0) {
1070             qemu_purge_queued_packets(nc);
1071             s->enabled = false;
1072             tap_update_fd_handler(s);
1073         }
1074         return ret;
1075     }
1076 }