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-common.h"
  42 #include "qemu/cutils.h"
  43 #include "qemu/error-report.h"
  44 #include "qemu/main-loop.h"
  45 #include "qemu/sockets.h"
  46
  47 #include "net/tap.h"
  48
  49 #include "net/vhost_net.h"
  50
  51 typedef struct TAPState {
  52     NetClientState nc;
  53     int fd;
  54     char down_script[1024];
  55     char down_script_arg[128];
  56     uint8_t buf[NET_BUFSIZE];
  57     bool read_poll;
  58     bool write_poll;
  59     bool using_vnet_hdr;
  60     bool has_ufo;
  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     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, true);
 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 #ifndef __sun__
 173 ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen)
 174 {
 175     return read(tapfd, buf, maxlen);
 176 }
 177 #endif
 178
 179 static void tap_send_completed(NetClientState *nc, ssize_t len)
 180 {
 181     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 182     tap_read_poll(s, true);
 183 }
 184
 185 static void tap_send(void *opaque)
 186 {
 187     TAPState *s = opaque;
 188     int size;
 189     int packets = 0;
 190
 191     while (true) {
 192         uint8_t *buf = s->buf;
 193         uint8_t min_pkt[ETH_ZLEN];
 194         size_t min_pktsz = sizeof(min_pkt);
 195
 196         size = tap_read_packet(s->fd, s->buf, sizeof(s->buf));
 197         if (size <= 0) {
 198             break;
 199         }
 200
 201         if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
 202             buf  += s->host_vnet_hdr_len;
 203             size -= s->host_vnet_hdr_len;
 204         }
 205
 206         if (!s->nc.peer->do_not_pad) {
 207             if (eth_pad_short_frame(min_pkt, &min_pktsz, buf, size)) {
 208                 buf = min_pkt;
 209                 size = min_pktsz;
 210             }
 211         }
 212
 213         size = qemu_send_packet_async(&s->nc, buf, size, tap_send_completed);
 214         if (size == 0) {
 215             tap_read_poll(s, false);
 216             break;
 217         } else if (size < 0) {
 218             break;
 219         }
 220
 221         /*
 222          * When the host keeps receiving more packets while tap_send() is
 223          * running we can hog the QEMU global mutex.  Limit the number of
 224          * packets that are processed per tap_send() callback to prevent
 225          * stalling the guest.
 226          */
 227         packets++;
 228         if (packets >= 50) {
 229             break;
 230         }
 231     }
 232 }
 233
 234 static bool tap_has_ufo(NetClientState *nc)
 235 {
 236     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 237
 238     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 239
 240     return s->has_ufo;
 241 }
 242
 243 static bool tap_has_vnet_hdr(NetClientState *nc)
 244 {
 245     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 246
 247     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 248
 249     return !!s->host_vnet_hdr_len;
 250 }
 251
 252 static bool tap_has_vnet_hdr_len(NetClientState *nc, int len)
 253 {
 254     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 255
 256     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 257
 258     return !!tap_probe_vnet_hdr_len(s->fd, len);
 259 }
 260
 261 static void tap_set_vnet_hdr_len(NetClientState *nc, int len)
 262 {
 263     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 264
 265     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 266     assert(len == sizeof(struct virtio_net_hdr_mrg_rxbuf) ||
 267            len == sizeof(struct virtio_net_hdr) ||
 268            len == sizeof(struct virtio_net_hdr_v1_hash));
 269
 270     tap_fd_set_vnet_hdr_len(s->fd, len);
 271     s->host_vnet_hdr_len = len;
 272 }
 273
 274 static void tap_using_vnet_hdr(NetClientState *nc, bool using_vnet_hdr)
 275 {
 276     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 277
 278     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 279     assert(!!s->host_vnet_hdr_len == using_vnet_hdr);
 280
 281     s->using_vnet_hdr = using_vnet_hdr;
 282 }
 283
 284 static int tap_set_vnet_le(NetClientState *nc, bool is_le)
 285 {
 286     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 287
 288     return tap_fd_set_vnet_le(s->fd, is_le);
 289 }
 290
 291 static int tap_set_vnet_be(NetClientState *nc, bool is_be)
 292 {
 293     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 294
 295     return tap_fd_set_vnet_be(s->fd, is_be);
 296 }
 297
 298 static void tap_set_offload(NetClientState *nc, int csum, int tso4,
 299                      int tso6, int ecn, int ufo)
 300 {
 301     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 302     if (s->fd < 0) {
 303         return;
 304     }
 305
 306     tap_fd_set_offload(s->fd, csum, tso4, tso6, ecn, ufo);
 307 }
 308
 309 static void tap_exit_notify(Notifier *notifier, void *data)
 310 {
 311     TAPState *s = container_of(notifier, TAPState, exit);
 312     Error *err = NULL;
 313
 314     if (s->down_script[0]) {
 315         launch_script(s->down_script, s->down_script_arg, s->fd, &err);
 316         if (err) {
 317             error_report_err(err);
 318         }
 319     }
 320 }
 321
 322 static void tap_cleanup(NetClientState *nc)
 323 {
 324     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 325
 326     if (s->vhost_net) {
 327         vhost_net_cleanup(s->vhost_net);
 328         g_free(s->vhost_net);
 329         s->vhost_net = NULL;
 330     }
 331
 332     qemu_purge_queued_packets(nc);
 333
 334     tap_exit_notify(&s->exit, NULL);
 335     qemu_remove_exit_notifier(&s->exit);
 336
 337     tap_read_poll(s, false);
 338     tap_write_poll(s, false);
 339     close(s->fd);
 340     s->fd = -1;
 341 }
 342
 343 static void tap_poll(NetClientState *nc, bool enable)
 344 {
 345     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 346     tap_read_poll(s, enable);
 347     tap_write_poll(s, enable);
 348 }
 349
 350 int tap_get_fd(NetClientState *nc)
 351 {
 352     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 353     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 354     return s->fd;
 355 }
 356
 357 /* fd support */
 358
 359 static NetClientInfo net_tap_info = {
 360     .type = NET_CLIENT_DRIVER_TAP,
 361     .size = sizeof(TAPState),
 362     .receive = tap_receive,
 363     .receive_raw = tap_receive_raw,
 364     .receive_iov = tap_receive_iov,
 365     .poll = tap_poll,
 366     .cleanup = tap_cleanup,
 367     .has_ufo = tap_has_ufo,
 368     .has_vnet_hdr = tap_has_vnet_hdr,
 369     .has_vnet_hdr_len = tap_has_vnet_hdr_len,
 370     .using_vnet_hdr = tap_using_vnet_hdr,
 371     .set_offload = tap_set_offload,
 372     .set_vnet_hdr_len = tap_set_vnet_hdr_len,
 373     .set_vnet_le = tap_set_vnet_le,
 374     .set_vnet_be = tap_set_vnet_be,
 375 };
 376
 377 static TAPState *net_tap_fd_init(NetClientState *peer,
 378                                  const char *model,
 379                                  const char *name,
 380                                  int fd,
 381                                  int vnet_hdr)
 382 {
 383     NetClientState *nc;
 384     TAPState *s;
 385
 386     nc = qemu_new_net_client(&net_tap_info, peer, model, name);
 387
 388     s = DO_UPCAST(TAPState, nc, nc);
 389
 390     s->fd = fd;
 391     s->host_vnet_hdr_len = vnet_hdr ? sizeof(struct virtio_net_hdr) : 0;
 392     s->using_vnet_hdr = false;
 393     s->has_ufo = tap_probe_has_ufo(s->fd);
 394     s->enabled = true;
 395     tap_set_offload(&s->nc, 0, 0, 0, 0, 0);
 396     /*
 397      * Make sure host header length is set correctly in tap:
 398      * it might have been modified by another instance of qemu.
 399      */
 400     if (tap_probe_vnet_hdr_len(s->fd, s->host_vnet_hdr_len)) {
 401         tap_fd_set_vnet_hdr_len(s->fd, s->host_vnet_hdr_len);
 402     }
 403     tap_read_poll(s, true);
 404     s->vhost_net = NULL;
 405
 406     s->exit.notify = tap_exit_notify;
 407     qemu_add_exit_notifier(&s->exit);
 408
 409     return s;
 410 }
 411
 412 static void launch_script(const char *setup_script, const char *ifname,
 413                           int fd, Error **errp)
 414 {
 415     int pid, status;
 416     char *args[3];
 417     char **parg;
 418
 419     /* try to launch network script */
 420     pid = fork();
 421     if (pid < 0) {
 422         error_setg_errno(errp, errno, "could not launch network script %s",
 423                          setup_script);
 424         return;
 425     }
 426     if (pid == 0) {
 427         int open_max = sysconf(_SC_OPEN_MAX), i;
 428
 429         for (i = 3; i < open_max; i++) {
 430             if (i != fd) {
 431                 close(i);
 432             }
 433         }
 434         parg = args;
 435         *parg++ = (char *)setup_script;
 436         *parg++ = (char *)ifname;
 437         *parg = NULL;
 438         execv(setup_script, args);
 439         _exit(1);
 440     } else {
 441         while (waitpid(pid, &status, 0) != pid) {
 442             /* loop */
 443         }
 444
 445         if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
 446             return;
 447         }
 448         error_setg(errp, "network script %s failed with status %d",
 449                    setup_script, status);
 450     }
 451 }
 452
 453 static int recv_fd(int c)
 454 {
 455     int fd;
 456     uint8_t msgbuf[CMSG_SPACE(sizeof(fd))];
 457     struct msghdr msg = {
 458         .msg_control = msgbuf,
 459         .msg_controllen = sizeof(msgbuf),
 460     };
 461     struct cmsghdr *cmsg;
 462     struct iovec iov;
 463     uint8_t req[1];
 464     ssize_t len;
 465
 466     cmsg = CMSG_FIRSTHDR(&msg);
 467     cmsg->cmsg_level = SOL_SOCKET;
 468     cmsg->cmsg_type = SCM_RIGHTS;
 469     cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
 470     msg.msg_controllen = cmsg->cmsg_len;
 471
 472     iov.iov_base = req;
 473     iov.iov_len = sizeof(req);
 474
 475     msg.msg_iov = &iov;
 476     msg.msg_iovlen = 1;
 477
 478     len = recvmsg(c, &msg, 0);
 479     if (len > 0) {
 480         memcpy(&fd, CMSG_DATA(cmsg), sizeof(fd));
 481         return fd;
 482     }
 483
 484     return len;
 485 }
 486
 487 static int net_bridge_run_helper(const char *helper, const char *bridge,
 488                                  Error **errp)
 489 {
 490     sigset_t oldmask, mask;
 491     g_autofree char *default_helper = NULL;
 492     int pid, status;
 493     char *args[5];
 494     char **parg;
 495     int sv[2];
 496
 497     sigemptyset(&mask);
 498     sigaddset(&mask, SIGCHLD);
 499     sigprocmask(SIG_BLOCK, &mask, &oldmask);
 500
 501     if (!helper) {
 502         helper = default_helper = get_relocated_path(DEFAULT_BRIDGE_HELPER);
 503     }
 504
 505     if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) == -1) {
 506         error_setg_errno(errp, errno, "socketpair() failed");
 507         return -1;
 508     }
 509
 510     /* try to launch bridge helper */
 511     pid = fork();
 512     if (pid < 0) {
 513         error_setg_errno(errp, errno, "Can't fork bridge helper");
 514         return -1;
 515     }
 516     if (pid == 0) {
 517         int open_max = sysconf(_SC_OPEN_MAX), i;
 518         char *fd_buf = NULL;
 519         char *br_buf = NULL;
 520         char *helper_cmd = NULL;
 521
 522         for (i = 3; i < open_max; i++) {
 523             if (i != sv[1]) {
 524                 close(i);
 525             }
 526         }
 527
 528         fd_buf = g_strdup_printf("%s%d", "--fd=", sv[1]);
 529
 530         if (strrchr(helper, ' ') || strrchr(helper, '\t')) {
 531             /* assume helper is a command */
 532
 533             if (strstr(helper, "--br=") == NULL) {
 534                 br_buf = g_strdup_printf("%s%s", "--br=", bridge);
 535             }
 536
 537             helper_cmd = g_strdup_printf("%s %s %s %s", helper,
 538                             "--use-vnet", fd_buf, br_buf ? br_buf : "");
 539
 540             parg = args;
 541             *parg++ = (char *)"sh";
 542             *parg++ = (char *)"-c";
 543             *parg++ = helper_cmd;
 544             *parg++ = NULL;
 545
 546             execv("/bin/sh", args);
 547             g_free(helper_cmd);
 548         } else {
 549             /* assume helper is just the executable path name */
 550
 551             br_buf = g_strdup_printf("%s%s", "--br=", bridge);
 552
 553             parg = args;
 554             *parg++ = (char *)helper;
 555             *parg++ = (char *)"--use-vnet";
 556             *parg++ = fd_buf;
 557             *parg++ = br_buf;
 558             *parg++ = NULL;
 559
 560             execv(helper, args);
 561         }
 562         g_free(fd_buf);
 563         g_free(br_buf);
 564         _exit(1);
 565
 566     } else {
 567         int fd;
 568         int saved_errno;
 569
 570         close(sv[1]);
 571
 572         do {
 573             fd = recv_fd(sv[0]);
 574         } while (fd == -1 && errno == EINTR);
 575         saved_errno = errno;
 576
 577         close(sv[0]);
 578
 579         while (waitpid(pid, &status, 0) != pid) {
 580             /* loop */
 581         }
 582         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 583         if (fd < 0) {
 584             error_setg_errno(errp, saved_errno,
 585                              "failed to recv file descriptor");
 586             return -1;
 587         }
 588         if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 589             error_setg(errp, "bridge helper failed");
 590             return -1;
 591         }
 592         return fd;
 593     }
 594 }
 595
 596 int net_init_bridge(const Netdev *netdev, const char *name,
 597                     NetClientState *peer, Error **errp)
 598 {
 599     const NetdevBridgeOptions *bridge;
 600     const char *helper, *br;
 601     TAPState *s;
 602     int fd, vnet_hdr;
 603     NetdevBridgeOptions *stored;
 604
 605     assert(netdev->type == NET_CLIENT_DRIVER_BRIDGE);
 606     bridge = &netdev->u.bridge;
 607     helper = bridge->has_helper ? bridge->helper : NULL;
 608     br     = bridge->has_br     ? bridge->br     : DEFAULT_BRIDGE_INTERFACE;
 609
 610     fd = net_bridge_run_helper(helper, br, errp);
 611     if (fd == -1) {
 612         return -1;
 613     }
 614
 615     qemu_set_nonblock(fd);
 616     vnet_hdr = tap_probe_vnet_hdr(fd, errp);
 617     if (vnet_hdr < 0) {
 618         close(fd);
 619         return -1;
 620     }
 621     s = net_tap_fd_init(peer, "bridge", name, fd, vnet_hdr);
 622
 623     /* Store startup parameters */
 624     s->nc.stored_config = g_new0(NetdevInfo, 1);
 625     s->nc.stored_config->type = NET_BACKEND_BRIDGE;
 626     stored = &s->nc.stored_config->u.bridge;
 627
 628     if (br) {
 629         stored->has_br = true;
 630         stored->br = g_strdup(br);
 631     }
 632
 633     if (helper) {
 634         stored->has_helper = true;
 635         stored->helper = g_strdup(helper);
 636     }
 637
 638     return 0;
 639 }
 640
 641 static int net_tap_init(const NetdevTapOptions *tap, int *vnet_hdr,
 642                         const char *setup_script, char *ifname,
 643                         size_t ifname_sz, int mq_required, Error **errp)
 644 {
 645     Error *err = NULL;
 646     int fd, vnet_hdr_required;
 647
 648     if (tap->has_vnet_hdr) {
 649         *vnet_hdr = tap->vnet_hdr;
 650         vnet_hdr_required = *vnet_hdr;
 651     } else {
 652         *vnet_hdr = 1;
 653         vnet_hdr_required = 0;
 654     }
 655
 656     TFR(fd = tap_open(ifname, ifname_sz, vnet_hdr, vnet_hdr_required,
 657                       mq_required, errp));
 658     if (fd < 0) {
 659         return -1;
 660     }
 661
 662     if (setup_script &&
 663         setup_script[0] != '\0' &&
 664         strcmp(setup_script, "no") != 0) {
 665         launch_script(setup_script, ifname, fd, &err);
 666         if (err) {
 667             error_propagate(errp, err);
 668             close(fd);
 669             return -1;
 670         }
 671     }
 672
 673     return fd;
 674 }
 675
 676 #define MAX_TAP_QUEUES 1024
 677
 678 static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
 679                              const char *model, const char *name,
 680                              const char *ifname, const char *script,
 681                              const char *downscript, const char *vhostfdname,
 682                              int vnet_hdr, int fd, NetdevInfo **common_stored,
 683                              Error **errp)
 684 {
 685     Error *err = NULL;
 686     TAPState *s = net_tap_fd_init(peer, model, name, fd, vnet_hdr);
 687     int vhostfd;
 688     NetdevTapOptions *stored;
 689
 690     tap_set_sndbuf(s->fd, tap, &err);
 691     if (err) {
 692         error_propagate(errp, err);
 693         return;
 694     }
 695
 696     /* Store startup parameters */
 697     if (!*common_stored) {
 698         *common_stored = g_new0(NetdevInfo, 1);
 699         (*common_stored)->type = NET_BACKEND_TAP;
 700         s->nc.stored_config = *common_stored;
 701     }
 702     stored = &(*common_stored)->u.tap;
 703
 704     if (tap->has_sndbuf && !stored->has_sndbuf) {
 705         stored->has_sndbuf = true;
 706         stored->sndbuf = tap->sndbuf;
 707     }
 708
 709     if (vnet_hdr && !stored->has_vnet_hdr) {
 710         stored->has_vnet_hdr = true;
 711         stored->vnet_hdr = true;
 712     }
 713
 714     if (tap->has_fd || tap->has_fds) {
 715         if (!stored->has_fds) {
 716             stored->has_fds = true;
 717             stored->fds = g_strdup_printf("%d", fd);
 718         } else {
 719             char *tmp_s = stored->fds;
 720             stored->fds = g_strdup_printf("%s:%d", stored->fds, fd);
 721             g_free(tmp_s);
 722         }
 723     } else if (tap->has_helper) {
 724         if (!stored->has_helper) {
 725             stored->has_helper = true;
 726             stored->helper = g_strdup(tap->helper);
 727         }
 728
 729         if (!stored->has_br) {
 730             stored->has_br = true;
 731             stored->br = tap->has_br ? g_strdup(tap->br) :
 732                                        g_strdup(DEFAULT_BRIDGE_INTERFACE);
 733         }
 734     } else {
 735         if (ifname && !stored->has_ifname) {
 736             stored->has_ifname = true;
 737             stored->ifname = g_strdup(ifname);
 738         }
 739
 740         if (script && !stored->has_script) {
 741             stored->has_script = true;
 742             stored->script = g_strdup(script);
 743         }
 744
 745         if (downscript && !stored->has_downscript) {
 746             stored->has_downscript = true;
 747             stored->downscript = g_strdup(downscript);
 748         }
 749
 750         if (strcmp(downscript, "no") != 0) {
 751             snprintf(s->down_script, sizeof(s->down_script), "%s", downscript);
 752             snprintf(s->down_script_arg, sizeof(s->down_script_arg),
 753                      "%s", ifname);
 754         }
 755     }
 756
 757     if (tap->has_vhost ? tap->vhost :
 758         vhostfdname || (tap->has_vhostforce && tap->vhostforce)) {
 759         VhostNetOptions options;
 760
 761         stored->has_vhost = true;
 762         stored->vhost = true;
 763
 764         if (tap->has_vhostforce && tap->vhostforce) {
 765             stored->has_vhostforce = true;
 766             stored->vhostforce = true;
 767         }
 768
 769         options.backend_type = VHOST_BACKEND_TYPE_KERNEL;
 770         options.net_backend = &s->nc;
 771         if (tap->has_poll_us) {
 772             stored->has_poll_us = true;
 773             stored->poll_us = tap->poll_us;
 774
 775             options.busyloop_timeout = tap->poll_us;
 776         } else {
 777             options.busyloop_timeout = 0;
 778         }
 779
 780         if (vhostfdname) {
 781             int ret;
 782
 783             vhostfd = monitor_fd_param(monitor_cur(), vhostfdname, &err);
 784             if (vhostfd == -1) {
 785                 if (tap->has_vhostforce && tap->vhostforce) {
 786                     error_propagate(errp, err);
 787                 } else {
 788                     warn_report_err(err);
 789                 }
 790                 return;
 791             }
 792             ret = qemu_try_set_nonblock(vhostfd);
 793             if (ret < 0) {
 794                 error_setg_errno(errp, -ret, "%s: Can't use file descriptor %d",
 795                                  name, fd);
 796                 return;
 797             }
 798         } else {
 799             vhostfd = open("/dev/vhost-net", O_RDWR);
 800             if (vhostfd < 0) {
 801                 if (tap->has_vhostforce && tap->vhostforce) {
 802                     error_setg_errno(errp, errno,
 803                                      "tap: open vhost char device failed");
 804                 } else {
 805                     warn_report("tap: open vhost char device failed: %s",
 806                                 strerror(errno));
 807                 }
 808                 return;
 809             }
 810             qemu_set_nonblock(vhostfd);
 811         }
 812         options.opaque = (void *)(uintptr_t)vhostfd;
 813
 814         if (!stored->has_vhostfds) {
 815             stored->has_vhostfds = true;
 816             stored->vhostfds = g_strdup_printf("%d", vhostfd);
 817         } else {
 818             char *tmp_s = stored->vhostfds;
 819             stored->vhostfds = g_strdup_printf("%s:%d", stored->fds, vhostfd);
 820             g_free(tmp_s);
 821         }
 822
 823         s->vhost_net = vhost_net_init(&options);
 824         if (!s->vhost_net) {
 825             if (tap->has_vhostforce && tap->vhostforce) {
 826                 error_setg(errp, VHOST_NET_INIT_FAILED);
 827             } else {
 828                 warn_report(VHOST_NET_INIT_FAILED);
 829             }
 830             return;
 831         }
 832     } else if (vhostfdname) {
 833         error_setg(errp, "vhostfd(s)= is not valid without vhost");
 834     }
 835 }
 836
 837 static int get_fds(char *str, char *fds[], int max)
 838 {
 839     char *ptr = str, *this;
 840     size_t len = strlen(str);
 841     int i = 0;
 842
 843     while (i < max && ptr < str + len) {
 844         this = strchr(ptr, ':');
 845
 846         if (this == NULL) {
 847             fds[i] = g_strdup(ptr);
 848         } else {
 849             fds[i] = g_strndup(ptr, this - ptr);
 850         }
 851
 852         i++;
 853         if (this == NULL) {
 854             break;
 855         } else {
 856             ptr = this + 1;
 857         }
 858     }
 859
 860     return i;
 861 }
 862
 863 int net_init_tap(const Netdev *netdev, const char *name,
 864                  NetClientState *peer, Error **errp)
 865 {
 866     const NetdevTapOptions *tap;
 867     int fd, vnet_hdr = 0, i = 0, queues;
 868     /* for the no-fd, no-helper case */
 869     const char *script;
 870     const char *downscript;
 871     Error *err = NULL;
 872     const char *vhostfdname;
 873     char ifname[128];
 874     int ret = 0;
 875     NetdevInfo *common_stored = NULL; /* will store configuration */
 876
 877     assert(netdev->type == NET_CLIENT_DRIVER_TAP);
 878     tap = &netdev->u.tap;
 879     queues = tap->has_queues ? tap->queues : 1;
 880     vhostfdname = tap->has_vhostfd ? tap->vhostfd : NULL;
 881     script = tap->has_script ? tap->script : NULL;
 882     downscript = tap->has_downscript ? tap->downscript : NULL;
 883
 884     /* QEMU hubs do not support multiqueue tap, in this case peer is set.
 885      * For -netdev, peer is always NULL. */
 886     if (peer && (tap->has_queues || tap->has_fds || tap->has_vhostfds)) {
 887         error_setg(errp, "Multiqueue tap cannot be used with hubs");
 888         return -1;
 889     }
 890
 891     if (tap->has_fd) {
 892         if (tap->has_ifname || tap->has_script || tap->has_downscript ||
 893             tap->has_vnet_hdr || tap->has_helper || tap->has_queues ||
 894             tap->has_fds || tap->has_vhostfds) {
 895             error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
 896                        "helper=, queues=, fds=, and vhostfds= "
 897                        "are invalid with fd=");
 898             return -1;
 899         }
 900
 901         fd = monitor_fd_param(monitor_cur(), tap->fd, errp);
 902         if (fd == -1) {
 903             return -1;
 904         }
 905
 906         ret = qemu_try_set_nonblock(fd);
 907         if (ret < 0) {
 908             error_setg_errno(errp, -ret, "%s: Can't use file descriptor %d",
 909                              name, fd);
 910             close(fd);
 911             return -1;
 912         }
 913
 914         vnet_hdr = tap_probe_vnet_hdr(fd, errp);
 915         if (vnet_hdr < 0) {
 916             close(fd);
 917             return -1;
 918         }
 919
 920         net_init_tap_one(tap, peer, "tap", name, NULL,
 921                          script, downscript,
 922                          vhostfdname, vnet_hdr, fd, &common_stored, &err);
 923         if (err) {
 924             error_propagate(errp, err);
 925             close(fd);
 926             return -1;
 927         }
 928     } else if (tap->has_fds) {
 929         char **fds;
 930         char **vhost_fds;
 931         int nfds = 0, nvhosts = 0;
 932
 933         if (tap->has_ifname || tap->has_script || tap->has_downscript ||
 934             tap->has_vnet_hdr || tap->has_helper || tap->has_queues ||
 935             tap->has_vhostfd) {
 936             error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
 937                        "helper=, queues=, and vhostfd= "
 938                        "are invalid with fds=");
 939             return -1;
 940         }
 941
 942         fds = g_new0(char *, MAX_TAP_QUEUES);
 943         vhost_fds = g_new0(char *, MAX_TAP_QUEUES);
 944
 945         nfds = get_fds(tap->fds, fds, MAX_TAP_QUEUES);
 946         if (tap->has_vhostfds) {
 947             nvhosts = get_fds(tap->vhostfds, vhost_fds, MAX_TAP_QUEUES);
 948             if (nfds != nvhosts) {
 949                 error_setg(errp, "The number of fds passed does not match "
 950                            "the number of vhostfds passed");
 951                 ret = -1;
 952                 goto free_fail;
 953             }
 954         }
 955
 956         for (i = 0; i < nfds; i++) {
 957             fd = monitor_fd_param(monitor_cur(), fds[i], errp);
 958             if (fd == -1) {
 959                 ret = -1;
 960                 goto free_fail;
 961             }
 962
 963             ret = qemu_try_set_nonblock(fd);
 964             if (ret < 0) {
 965                 error_setg_errno(errp, -ret, "%s: Can't use file descriptor %d",
 966                                  name, fd);
 967                 goto free_fail;
 968             }
 969
 970             if (i == 0) {
 971                 vnet_hdr = tap_probe_vnet_hdr(fd, errp);
 972                 if (vnet_hdr < 0) {
 973                     goto free_fail;
 974                 }
 975             } else if (vnet_hdr != tap_probe_vnet_hdr(fd, NULL)) {
 976                 error_setg(errp,
 977                            "vnet_hdr not consistent across given tap fds");
 978                 ret = -1;
 979                 goto free_fail;
 980             }
 981
 982             net_init_tap_one(tap, peer, "tap", name, ifname,
 983                              script, downscript,
 984                              tap->has_vhostfds ? vhost_fds[i] : NULL,
 985                              vnet_hdr, fd, &common_stored, &err);
 986             if (err) {
 987                 error_propagate(errp, err);
 988                 ret = -1;
 989                 goto free_fail;
 990             }
 991         }
 992
 993 free_fail:
 994         for (i = 0; i < nvhosts; i++) {
 995             g_free(vhost_fds[i]);
 996         }
 997         for (i = 0; i < nfds; i++) {
 998             g_free(fds[i]);
 999         }
1000         g_free(fds);
1001         g_free(vhost_fds);
1002         return ret;
1003     } else if (tap->has_helper) {
1004         if (tap->has_ifname || tap->has_script || tap->has_downscript ||
1005             tap->has_vnet_hdr || tap->has_queues || tap->has_vhostfds) {
1006             error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
1007                        "queues=, and vhostfds= are invalid with helper=");
1008             return -1;
1009         }
1010
1011         fd = net_bridge_run_helper(tap->helper,
1012                                    tap->has_br ?
1013                                    tap->br : DEFAULT_BRIDGE_INTERFACE,
1014                                    errp);
1015         if (fd == -1) {
1016             return -1;
1017         }
1018
1019         qemu_set_nonblock(fd);
1020         vnet_hdr = tap_probe_vnet_hdr(fd, errp);
1021         if (vnet_hdr < 0) {
1022             close(fd);
1023             return -1;
1024         }
1025
1026         net_init_tap_one(tap, peer, "bridge", name, ifname,
1027                          script, downscript, vhostfdname,
1028                          vnet_hdr, fd, &common_stored, &err);
1029         if (err) {
1030             error_propagate(errp, err);
1031             close(fd);
1032             return -1;
1033         }
1034     } else {
1035         g_autofree char *default_script = NULL;
1036         g_autofree char *default_downscript = NULL;
1037         if (tap->has_vhostfds) {
1038             error_setg(errp, "vhostfds= is invalid if fds= wasn't specified");
1039             return -1;
1040         }
1041
1042         if (!script) {
1043             script = default_script = get_relocated_path(DEFAULT_NETWORK_SCRIPT);
1044         }
1045         if (!downscript) {
1046             downscript = default_downscript =
1047                                  get_relocated_path(DEFAULT_NETWORK_DOWN_SCRIPT);
1048         }
1049
1050         if (tap->has_ifname) {
1051             pstrcpy(ifname, sizeof ifname, tap->ifname);
1052         } else {
1053             ifname[0] = '\0';
1054         }
1055
1056         for (i = 0; i < queues; i++) {
1057             fd = net_tap_init(tap, &vnet_hdr, i >= 1 ? "no" : script,
1058                               ifname, sizeof ifname, queues > 1, errp);
1059             if (fd == -1) {
1060                 return -1;
1061             }
1062
1063             if (queues > 1 && i == 0 && !tap->has_ifname) {
1064                 if (tap_fd_get_ifname(fd, ifname)) {
1065                     error_setg(errp, "Fail to get ifname");
1066                     close(fd);
1067                     return -1;
1068                 }
1069             }
1070
1071             net_init_tap_one(tap, peer, "tap", name, ifname,
1072                              i >= 1 ? "no" : script,
1073                              i >= 1 ? "no" : downscript,
1074                              vhostfdname, vnet_hdr, fd,
1075                              &common_stored, &err);
1076             if (err) {
1077                 error_propagate(errp, err);
1078                 close(fd);
1079                 return -1;
1080             }
1081         }
1082     }
1083
1084     return 0;
1085 }
1086
1087 VHostNetState *tap_get_vhost_net(NetClientState *nc)
1088 {
1089     TAPState *s = DO_UPCAST(TAPState, nc, nc);
1090     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
1091     return s->vhost_net;
1092 }
1093
1094 int tap_enable(NetClientState *nc)
1095 {
1096     TAPState *s = DO_UPCAST(TAPState, nc, nc);
1097     int ret;
1098
1099     if (s->enabled) {
1100         return 0;
1101     } else {
1102         ret = tap_fd_enable(s->fd);
1103         if (ret == 0) {
1104             s->enabled = true;
1105             tap_update_fd_handler(s);
1106         }
1107         return ret;
1108     }
1109 }
1110
1111 int tap_disable(NetClientState *nc)
1112 {
1113     TAPState *s = DO_UPCAST(TAPState, nc, nc);
1114     int ret;
1115
1116     if (s->enabled == 0) {
1117         return 0;
1118     } else {
1119         ret = tap_fd_disable(s->fd);
1120         if (ret == 0) {
1121             qemu_purge_queued_packets(nc);
1122             s->enabled = false;
1123             tap_update_fd_handler(s);
1124         }
1125         return ret;
1126     }
1127 }