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 "net/vhost_net.h"
  46
  47 typedef struct TAPState {
  48     NetClientState nc;
  49     int fd;
  50     char down_script[1024];
  51     char down_script_arg[128];
  52     uint8_t buf[NET_BUFSIZE];
  53     bool read_poll;
  54     bool write_poll;
  55     bool using_vnet_hdr;
  56     bool has_ufo;
  57     bool enabled;
  58     VHostNetState *vhost_net;
  59     unsigned host_vnet_hdr_len;
  60 } TAPState;
  61
  62 static void launch_script(const char *setup_script, const char *ifname,
  63                           int fd, Error **errp);
  64
  65 static int tap_can_send(void *opaque);
  66 static void tap_send(void *opaque);
  67 static void tap_writable(void *opaque);
  68
  69 static void tap_update_fd_handler(TAPState *s)
  70 {
  71     qemu_set_fd_handler2(s->fd,
  72                          s->read_poll && s->enabled ? tap_can_send : NULL,
  73                          s->read_poll && s->enabled ? tap_send     : NULL,
  74                          s->write_poll && s->enabled ? tap_writable : NULL,
  75                          s);
  76 }
  77
  78 static void tap_read_poll(TAPState *s, bool enable)
  79 {
  80     s->read_poll = enable;
  81     tap_update_fd_handler(s);
  82 }
  83
  84 static void tap_write_poll(TAPState *s, bool enable)
  85 {
  86     s->write_poll = enable;
  87     tap_update_fd_handler(s);
  88 }
  89
  90 static void tap_writable(void *opaque)
  91 {
  92     TAPState *s = opaque;
  93
  94     tap_write_poll(s, false);
  95
  96     qemu_flush_queued_packets(&s->nc);
  97 }
  98
  99 static ssize_t tap_write_packet(TAPState *s, const struct iovec *iov, int iovcnt)
 100 {
 101     ssize_t len;
 102
 103     do {
 104         len = writev(s->fd, iov, iovcnt);
 105     } while (len == -1 && errno == EINTR);
 106
 107     if (len == -1 && errno == EAGAIN) {
 108         tap_write_poll(s, true);
 109         return 0;
 110     }
 111
 112     return len;
 113 }
 114
 115 static ssize_t tap_receive_iov(NetClientState *nc, const struct iovec *iov,
 116                                int iovcnt)
 117 {
 118     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 119     const struct iovec *iovp = iov;
 120     struct iovec iov_copy[iovcnt + 1];
 121     struct virtio_net_hdr_mrg_rxbuf hdr = { };
 122
 123     if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
 124         iov_copy[0].iov_base = &hdr;
 125         iov_copy[0].iov_len =  s->host_vnet_hdr_len;
 126         memcpy(&iov_copy[1], iov, iovcnt * sizeof(*iov));
 127         iovp = iov_copy;
 128         iovcnt++;
 129     }
 130
 131     return tap_write_packet(s, iovp, iovcnt);
 132 }
 133
 134 static ssize_t tap_receive_raw(NetClientState *nc, const uint8_t *buf, size_t size)
 135 {
 136     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 137     struct iovec iov[2];
 138     int iovcnt = 0;
 139     struct virtio_net_hdr_mrg_rxbuf hdr = { };
 140
 141     if (s->host_vnet_hdr_len) {
 142         iov[iovcnt].iov_base = &hdr;
 143         iov[iovcnt].iov_len  = s->host_vnet_hdr_len;
 144         iovcnt++;
 145     }
 146
 147     iov[iovcnt].iov_base = (char *)buf;
 148     iov[iovcnt].iov_len  = size;
 149     iovcnt++;
 150
 151     return tap_write_packet(s, iov, iovcnt);
 152 }
 153
 154 static ssize_t tap_receive(NetClientState *nc, const uint8_t *buf, size_t size)
 155 {
 156     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 157     struct iovec iov[1];
 158
 159     if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
 160         return tap_receive_raw(nc, buf, size);
 161     }
 162
 163     iov[0].iov_base = (char *)buf;
 164     iov[0].iov_len  = size;
 165
 166     return tap_write_packet(s, iov, 1);
 167 }
 168
 169 static int tap_can_send(void *opaque)
 170 {
 171     TAPState *s = opaque;
 172
 173     return qemu_can_send_packet(&s->nc);
 174 }
 175
 176 #ifndef __sun__
 177 ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen)
 178 {
 179     return read(tapfd, buf, maxlen);
 180 }
 181 #endif
 182
 183 static void tap_send_completed(NetClientState *nc, ssize_t len)
 184 {
 185     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 186     tap_read_poll(s, true);
 187 }
 188
 189 static void tap_send(void *opaque)
 190 {
 191     TAPState *s = opaque;
 192     int size;
 193     int packets = 0;
 194
 195     while (qemu_can_send_packet(&s->nc)) {
 196         uint8_t *buf = s->buf;
 197
 198         size = tap_read_packet(s->fd, s->buf, sizeof(s->buf));
 199         if (size <= 0) {
 200             break;
 201         }
 202
 203         if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
 204             buf  += s->host_vnet_hdr_len;
 205             size -= s->host_vnet_hdr_len;
 206         }
 207
 208         size = qemu_send_packet_async(&s->nc, buf, size, tap_send_completed);
 209         if (size == 0) {
 210             tap_read_poll(s, false);
 211             break;
 212         } else if (size < 0) {
 213             break;
 214         }
 215
 216         /*
 217          * When the host keeps receiving more packets while tap_send() is
 218          * running we can hog the QEMU global mutex.  Limit the number of
 219          * packets that are processed per tap_send() callback to prevent
 220          * stalling the guest.
 221          */
 222         packets++;
 223         if (packets >= 50) {
 224             break;
 225         }
 226     }
 227 }
 228
 229 static bool tap_has_ufo(NetClientState *nc)
 230 {
 231     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 232
 233     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP);
 234
 235     return s->has_ufo;
 236 }
 237
 238 static bool tap_has_vnet_hdr(NetClientState *nc)
 239 {
 240     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 241
 242     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP);
 243
 244     return !!s->host_vnet_hdr_len;
 245 }
 246
 247 static bool tap_has_vnet_hdr_len(NetClientState *nc, int len)
 248 {
 249     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 250
 251     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP);
 252
 253     return !!tap_probe_vnet_hdr_len(s->fd, len);
 254 }
 255
 256 static void tap_set_vnet_hdr_len(NetClientState *nc, int len)
 257 {
 258     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 259
 260     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP);
 261     assert(len == sizeof(struct virtio_net_hdr_mrg_rxbuf) ||
 262            len == sizeof(struct virtio_net_hdr));
 263
 264     tap_fd_set_vnet_hdr_len(s->fd, len);
 265     s->host_vnet_hdr_len = len;
 266 }
 267
 268 static void tap_using_vnet_hdr(NetClientState *nc, bool using_vnet_hdr)
 269 {
 270     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 271
 272     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP);
 273     assert(!!s->host_vnet_hdr_len == using_vnet_hdr);
 274
 275     s->using_vnet_hdr = using_vnet_hdr;
 276 }
 277
 278 static void tap_set_offload(NetClientState *nc, int csum, int tso4,
 279                      int tso6, int ecn, int ufo)
 280 {
 281     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 282     if (s->fd < 0) {
 283         return;
 284     }
 285
 286     tap_fd_set_offload(s->fd, csum, tso4, tso6, ecn, ufo);
 287 }
 288
 289 static void tap_cleanup(NetClientState *nc)
 290 {
 291     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 292     Error *err = NULL;
 293
 294     if (s->vhost_net) {
 295         vhost_net_cleanup(s->vhost_net);
 296         s->vhost_net = NULL;
 297     }
 298
 299     qemu_purge_queued_packets(nc);
 300
 301     if (s->down_script[0]) {
 302         launch_script(s->down_script, s->down_script_arg, s->fd, &err);
 303         if (err) {
 304             error_report_err(err);
 305         }
 306     }
 307
 308     tap_read_poll(s, false);
 309     tap_write_poll(s, false);
 310     close(s->fd);
 311     s->fd = -1;
 312 }
 313
 314 static void tap_poll(NetClientState *nc, bool enable)
 315 {
 316     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 317     tap_read_poll(s, enable);
 318     tap_write_poll(s, enable);
 319 }
 320
 321 int tap_get_fd(NetClientState *nc)
 322 {
 323     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 324     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP);
 325     return s->fd;
 326 }
 327
 328 /* fd support */
 329
 330 static NetClientInfo net_tap_info = {
 331     .type = NET_CLIENT_OPTIONS_KIND_TAP,
 332     .size = sizeof(TAPState),
 333     .receive = tap_receive,
 334     .receive_raw = tap_receive_raw,
 335     .receive_iov = tap_receive_iov,
 336     .poll = tap_poll,
 337     .cleanup = tap_cleanup,
 338     .has_ufo = tap_has_ufo,
 339     .has_vnet_hdr = tap_has_vnet_hdr,
 340     .has_vnet_hdr_len = tap_has_vnet_hdr_len,
 341     .using_vnet_hdr = tap_using_vnet_hdr,
 342     .set_offload = tap_set_offload,
 343     .set_vnet_hdr_len = tap_set_vnet_hdr_len,
 344 };
 345
 346 static TAPState *net_tap_fd_init(NetClientState *peer,
 347                                  const char *model,
 348                                  const char *name,
 349                                  int fd,
 350                                  int vnet_hdr)
 351 {
 352     NetClientState *nc;
 353     TAPState *s;
 354
 355     nc = qemu_new_net_client(&net_tap_info, peer, model, name);
 356
 357     s = DO_UPCAST(TAPState, nc, nc);
 358
 359     s->fd = fd;
 360     s->host_vnet_hdr_len = vnet_hdr ? sizeof(struct virtio_net_hdr) : 0;
 361     s->using_vnet_hdr = false;
 362     s->has_ufo = tap_probe_has_ufo(s->fd);
 363     s->enabled = true;
 364     tap_set_offload(&s->nc, 0, 0, 0, 0, 0);
 365     /*
 366      * Make sure host header length is set correctly in tap:
 367      * it might have been modified by another instance of qemu.
 368      */
 369     if (tap_probe_vnet_hdr_len(s->fd, s->host_vnet_hdr_len)) {
 370         tap_fd_set_vnet_hdr_len(s->fd, s->host_vnet_hdr_len);
 371     }
 372     tap_read_poll(s, true);
 373     s->vhost_net = NULL;
 374     return s;
 375 }
 376
 377 static void launch_script(const char *setup_script, const char *ifname,
 378                           int fd, Error **errp)
 379 {
 380     int pid, status;
 381     char *args[3];
 382     char **parg;
 383
 384     /* try to launch network script */
 385     pid = fork();
 386     if (pid < 0) {
 387         error_setg_errno(errp, errno, "could not launch network script %s",
 388                          setup_script);
 389         return;
 390     }
 391     if (pid == 0) {
 392         int open_max = sysconf(_SC_OPEN_MAX), i;
 393
 394         for (i = 3; i < open_max; i++) {
 395             if (i != fd) {
 396                 close(i);
 397             }
 398         }
 399         parg = args;
 400         *parg++ = (char *)setup_script;
 401         *parg++ = (char *)ifname;
 402         *parg = NULL;
 403         execv(setup_script, args);
 404         _exit(1);
 405     } else {
 406         while (waitpid(pid, &status, 0) != pid) {
 407             /* loop */
 408         }
 409
 410         if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
 411             return;
 412         }
 413         error_setg(errp, "network script %s failed with status %d",
 414                    setup_script, status);
 415     }
 416 }
 417
 418 static int recv_fd(int c)
 419 {
 420     int fd;
 421     uint8_t msgbuf[CMSG_SPACE(sizeof(fd))];
 422     struct msghdr msg = {
 423         .msg_control = msgbuf,
 424         .msg_controllen = sizeof(msgbuf),
 425     };
 426     struct cmsghdr *cmsg;
 427     struct iovec iov;
 428     uint8_t req[1];
 429     ssize_t len;
 430
 431     cmsg = CMSG_FIRSTHDR(&msg);
 432     cmsg->cmsg_level = SOL_SOCKET;
 433     cmsg->cmsg_type = SCM_RIGHTS;
 434     cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
 435     msg.msg_controllen = cmsg->cmsg_len;
 436
 437     iov.iov_base = req;
 438     iov.iov_len = sizeof(req);
 439
 440     msg.msg_iov = &iov;
 441     msg.msg_iovlen = 1;
 442
 443     len = recvmsg(c, &msg, 0);
 444     if (len > 0) {
 445         memcpy(&fd, CMSG_DATA(cmsg), sizeof(fd));
 446         return fd;
 447     }
 448
 449     return len;
 450 }
 451
 452 static int net_bridge_run_helper(const char *helper, const char *bridge,
 453                                  Error **errp)
 454 {
 455     sigset_t oldmask, mask;
 456     int pid, status;
 457     char *args[5];
 458     char **parg;
 459     int sv[2];
 460
 461     sigemptyset(&mask);
 462     sigaddset(&mask, SIGCHLD);
 463     sigprocmask(SIG_BLOCK, &mask, &oldmask);
 464
 465     if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) == -1) {
 466         error_setg_errno(errp, errno, "socketpair() failed");
 467         return -1;
 468     }
 469
 470     /* try to launch bridge helper */
 471     pid = fork();
 472     if (pid < 0) {
 473         error_setg_errno(errp, errno, "Can't fork bridge helper");
 474         return -1;
 475     }
 476     if (pid == 0) {
 477         int open_max = sysconf(_SC_OPEN_MAX), i;
 478         char fd_buf[6+10];
 479         char br_buf[6+IFNAMSIZ] = {0};
 480         char helper_cmd[PATH_MAX + sizeof(fd_buf) + sizeof(br_buf) + 15];
 481
 482         for (i = 3; i < open_max; i++) {
 483             if (i != sv[1]) {
 484                 close(i);
 485             }
 486         }
 487
 488         snprintf(fd_buf, sizeof(fd_buf), "%s%d", "--fd=", sv[1]);
 489
 490         if (strrchr(helper, ' ') || strrchr(helper, '\t')) {
 491             /* assume helper is a command */
 492
 493             if (strstr(helper, "--br=") == NULL) {
 494                 snprintf(br_buf, sizeof(br_buf), "%s%s", "--br=", bridge);
 495             }
 496
 497             snprintf(helper_cmd, sizeof(helper_cmd), "%s %s %s %s",
 498                      helper, "--use-vnet", fd_buf, br_buf);
 499
 500             parg = args;
 501             *parg++ = (char *)"sh";
 502             *parg++ = (char *)"-c";
 503             *parg++ = helper_cmd;
 504             *parg++ = NULL;
 505
 506             execv("/bin/sh", args);
 507         } else {
 508             /* assume helper is just the executable path name */
 509
 510             snprintf(br_buf, sizeof(br_buf), "%s%s", "--br=", bridge);
 511
 512             parg = args;
 513             *parg++ = (char *)helper;
 514             *parg++ = (char *)"--use-vnet";
 515             *parg++ = fd_buf;
 516             *parg++ = br_buf;
 517             *parg++ = NULL;
 518
 519             execv(helper, args);
 520         }
 521         _exit(1);
 522
 523     } else {
 524         int fd;
 525         int saved_errno;
 526
 527         close(sv[1]);
 528
 529         do {
 530             fd = recv_fd(sv[0]);
 531         } while (fd == -1 && errno == EINTR);
 532         saved_errno = errno;
 533
 534         close(sv[0]);
 535
 536         while (waitpid(pid, &status, 0) != pid) {
 537             /* loop */
 538         }
 539         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 540         if (fd < 0) {
 541             error_setg_errno(errp, saved_errno,
 542                              "failed to recv file descriptor");
 543             return -1;
 544         }
 545         if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 546             error_setg(errp, "bridge helper failed");
 547             return -1;
 548         }
 549         return fd;
 550     }
 551 }
 552
 553 int net_init_bridge(const NetClientOptions *opts, const char *name,
 554                     NetClientState *peer, Error **errp)
 555 {
 556     const NetdevBridgeOptions *bridge;
 557     const char *helper, *br;
 558     TAPState *s;
 559     int fd, vnet_hdr;
 560
 561     assert(opts->kind == NET_CLIENT_OPTIONS_KIND_BRIDGE);
 562     bridge = opts->bridge;
 563
 564     helper = bridge->has_helper ? bridge->helper : DEFAULT_BRIDGE_HELPER;
 565     br     = bridge->has_br     ? bridge->br     : DEFAULT_BRIDGE_INTERFACE;
 566
 567     fd = net_bridge_run_helper(helper, br, errp);
 568     if (fd == -1) {
 569         return -1;
 570     }
 571
 572     fcntl(fd, F_SETFL, O_NONBLOCK);
 573     vnet_hdr = tap_probe_vnet_hdr(fd);
 574     s = net_tap_fd_init(peer, "bridge", name, fd, vnet_hdr);
 575
 576     snprintf(s->nc.info_str, sizeof(s->nc.info_str), "helper=%s,br=%s", helper,
 577              br);
 578
 579     return 0;
 580 }
 581
 582 static int net_tap_init(const NetdevTapOptions *tap, int *vnet_hdr,
 583                         const char *setup_script, char *ifname,
 584                         size_t ifname_sz, int mq_required, Error **errp)
 585 {
 586     Error *err = NULL;
 587     int fd, vnet_hdr_required;
 588
 589     if (tap->has_vnet_hdr) {
 590         *vnet_hdr = tap->vnet_hdr;
 591         vnet_hdr_required = *vnet_hdr;
 592     } else {
 593         *vnet_hdr = 1;
 594         vnet_hdr_required = 0;
 595     }
 596
 597     TFR(fd = tap_open(ifname, ifname_sz, vnet_hdr, vnet_hdr_required,
 598                       mq_required, errp));
 599     if (fd < 0) {
 600         /* FIXME drop when all tap_open() store an Error */
 601         if (errp && !*errp) {
 602             error_setg(errp, "can't open tap device");
 603         }
 604         return -1;
 605     }
 606
 607     if (setup_script &&
 608         setup_script[0] != '\0' &&
 609         strcmp(setup_script, "no") != 0) {
 610         launch_script(setup_script, ifname, fd, &err);
 611         if (err) {
 612             error_propagate(errp, err);
 613             close(fd);
 614             return -1;
 615         }
 616     }
 617
 618     return fd;
 619 }
 620
 621 #define MAX_TAP_QUEUES 1024
 622
 623 static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
 624                              const char *model, const char *name,
 625                              const char *ifname, const char *script,
 626                              const char *downscript, const char *vhostfdname,
 627                              int vnet_hdr, int fd, Error **errp)
 628 {
 629     Error *err = NULL;
 630     TAPState *s = net_tap_fd_init(peer, model, name, fd, vnet_hdr);
 631     int vhostfd;
 632
 633     tap_set_sndbuf(s->fd, tap, &err);
 634     if (err) {
 635         error_propagate(errp, err);
 636         return;
 637     }
 638
 639     if (tap->has_fd || tap->has_fds) {
 640         snprintf(s->nc.info_str, sizeof(s->nc.info_str), "fd=%d", fd);
 641     } else if (tap->has_helper) {
 642         snprintf(s->nc.info_str, sizeof(s->nc.info_str), "helper=%s",
 643                  tap->helper);
 644     } else {
 645         snprintf(s->nc.info_str, sizeof(s->nc.info_str),
 646                  "ifname=%s,script=%s,downscript=%s", ifname, script,
 647                  downscript);
 648
 649         if (strcmp(downscript, "no") != 0) {
 650             snprintf(s->down_script, sizeof(s->down_script), "%s", downscript);
 651             snprintf(s->down_script_arg, sizeof(s->down_script_arg),
 652                      "%s", ifname);
 653         }
 654     }
 655
 656     if (tap->has_vhost ? tap->vhost :
 657         vhostfdname || (tap->has_vhostforce && tap->vhostforce)) {
 658         VhostNetOptions options;
 659
 660         options.backend_type = VHOST_BACKEND_TYPE_KERNEL;
 661         options.net_backend = &s->nc;
 662         options.force = tap->has_vhostforce && tap->vhostforce;
 663
 664         if (tap->has_vhostfd || tap->has_vhostfds) {
 665             vhostfd = monitor_fd_param(cur_mon, vhostfdname, &err);
 666             if (vhostfd == -1) {
 667                 error_propagate(errp, err);
 668                 return;
 669             }
 670         } else {
 671             vhostfd = open("/dev/vhost-net", O_RDWR);
 672             if (vhostfd < 0) {
 673                 error_setg_errno(errp, errno,
 674                                  "tap: open vhost char device failed");
 675                 return;
 676             }
 677         }
 678         options.opaque = (void *)(uintptr_t)vhostfd;
 679
 680         s->vhost_net = vhost_net_init(&options);
 681         if (!s->vhost_net) {
 682             error_setg(errp,
 683                        "vhost-net requested but could not be initialized");
 684             return;
 685         }
 686     } else if (tap->has_vhostfd || tap->has_vhostfds) {
 687         error_setg(errp, "vhostfd= is not valid without vhost");
 688     }
 689 }
 690
 691 static int get_fds(char *str, char *fds[], int max)
 692 {
 693     char *ptr = str, *this;
 694     size_t len = strlen(str);
 695     int i = 0;
 696
 697     while (i < max && ptr < str + len) {
 698         this = strchr(ptr, ':');
 699
 700         if (this == NULL) {
 701             fds[i] = g_strdup(ptr);
 702         } else {
 703             fds[i] = g_strndup(ptr, this - ptr);
 704         }
 705
 706         i++;
 707         if (this == NULL) {
 708             break;
 709         } else {
 710             ptr = this + 1;
 711         }
 712     }
 713
 714     return i;
 715 }
 716
 717 int net_init_tap(const NetClientOptions *opts, const char *name,
 718                  NetClientState *peer, Error **errp)
 719 {
 720     /* FIXME error_setg(errp, ...) on failure */
 721     const NetdevTapOptions *tap;
 722     int fd, vnet_hdr = 0, i = 0, queues;
 723     /* for the no-fd, no-helper case */
 724     const char *script = NULL; /* suppress wrong "uninit'd use" gcc warning */
 725     const char *downscript = NULL;
 726     Error *err = NULL;
 727     const char *vhostfdname;
 728     char ifname[128];
 729
 730     assert(opts->kind == NET_CLIENT_OPTIONS_KIND_TAP);
 731     tap = opts->tap;
 732     queues = tap->has_queues ? tap->queues : 1;
 733     vhostfdname = tap->has_vhostfd ? tap->vhostfd : NULL;
 734
 735     /* QEMU vlans does not support multiqueue tap, in this case peer is set.
 736      * For -netdev, peer is always NULL. */
 737     if (peer && (tap->has_queues || tap->has_fds || tap->has_vhostfds)) {
 738         error_report("Multiqueue tap cannot be used with QEMU vlans");
 739         return -1;
 740     }
 741
 742     if (tap->has_fd) {
 743         if (tap->has_ifname || tap->has_script || tap->has_downscript ||
 744             tap->has_vnet_hdr || tap->has_helper || tap->has_queues ||
 745             tap->has_fds || tap->has_vhostfds) {
 746             error_report("ifname=, script=, downscript=, vnet_hdr=, "
 747                          "helper=, queues=, fds=, and vhostfds= "
 748                          "are invalid with fd=");
 749             return -1;
 750         }
 751
 752         fd = monitor_fd_param(cur_mon, tap->fd, &err);
 753         if (fd == -1) {
 754             error_report_err(err);
 755             return -1;
 756         }
 757
 758         fcntl(fd, F_SETFL, O_NONBLOCK);
 759
 760         vnet_hdr = tap_probe_vnet_hdr(fd);
 761
 762         net_init_tap_one(tap, peer, "tap", name, NULL,
 763                          script, downscript,
 764                          vhostfdname, vnet_hdr, fd, &err);
 765         if (err) {
 766             error_report_err(err);
 767             return -1;
 768         }
 769     } else if (tap->has_fds) {
 770         char *fds[MAX_TAP_QUEUES];
 771         char *vhost_fds[MAX_TAP_QUEUES];
 772         int nfds, nvhosts;
 773
 774         if (tap->has_ifname || tap->has_script || tap->has_downscript ||
 775             tap->has_vnet_hdr || tap->has_helper || tap->has_queues ||
 776             tap->has_vhostfd) {
 777             error_report("ifname=, script=, downscript=, vnet_hdr=, "
 778                          "helper=, queues=, and vhostfd= "
 779                          "are invalid with fds=");
 780             return -1;
 781         }
 782
 783         nfds = get_fds(tap->fds, fds, MAX_TAP_QUEUES);
 784         if (tap->has_vhostfds) {
 785             nvhosts = get_fds(tap->vhostfds, vhost_fds, MAX_TAP_QUEUES);
 786             if (nfds != nvhosts) {
 787                 error_report("The number of fds passed does not match the "
 788                              "number of vhostfds passed");
 789                 return -1;
 790             }
 791         }
 792
 793         for (i = 0; i < nfds; i++) {
 794             fd = monitor_fd_param(cur_mon, fds[i], &err);
 795             if (fd == -1) {
 796                 error_report_err(err);
 797                 return -1;
 798             }
 799
 800             fcntl(fd, F_SETFL, O_NONBLOCK);
 801
 802             if (i == 0) {
 803                 vnet_hdr = tap_probe_vnet_hdr(fd);
 804             } else if (vnet_hdr != tap_probe_vnet_hdr(fd)) {
 805                 error_report("vnet_hdr not consistent across given tap fds");
 806                 return -1;
 807             }
 808
 809             net_init_tap_one(tap, peer, "tap", name, ifname,
 810                              script, downscript,
 811                              tap->has_vhostfds ? vhost_fds[i] : NULL,
 812                              vnet_hdr, fd, &err);
 813             if (err) {
 814                 error_report_err(err);
 815                 return -1;
 816             }
 817         }
 818     } else if (tap->has_helper) {
 819         if (tap->has_ifname || tap->has_script || tap->has_downscript ||
 820             tap->has_vnet_hdr || tap->has_queues || tap->has_vhostfds) {
 821             error_report("ifname=, script=, downscript=, and vnet_hdr= "
 822                          "queues=, and vhostfds= are invalid with helper=");
 823             return -1;
 824         }
 825
 826         fd = net_bridge_run_helper(tap->helper, DEFAULT_BRIDGE_INTERFACE,
 827                                    errp);
 828         if (fd == -1) {
 829             return -1;
 830         }
 831
 832         fcntl(fd, F_SETFL, O_NONBLOCK);
 833         vnet_hdr = tap_probe_vnet_hdr(fd);
 834
 835         net_init_tap_one(tap, peer, "bridge", name, ifname,
 836                          script, downscript, vhostfdname,
 837                          vnet_hdr, fd, &err);
 838         if (err) {
 839             error_report_err(err);
 840             close(fd);
 841             return -1;
 842         }
 843     } else {
 844         if (tap->has_vhostfds) {
 845             error_report("vhostfds= is invalid if fds= wasn't specified");
 846             return -1;
 847         }
 848         script = tap->has_script ? tap->script : DEFAULT_NETWORK_SCRIPT;
 849         downscript = tap->has_downscript ? tap->downscript :
 850             DEFAULT_NETWORK_DOWN_SCRIPT;
 851
 852         if (tap->has_ifname) {
 853             pstrcpy(ifname, sizeof ifname, tap->ifname);
 854         } else {
 855             ifname[0] = '\0';
 856         }
 857
 858         for (i = 0; i < queues; i++) {
 859             fd = net_tap_init(tap, &vnet_hdr, i >= 1 ? "no" : script,
 860                               ifname, sizeof ifname, queues > 1, &err);
 861             if (fd == -1) {
 862                 error_report_err(err);
 863                 return -1;
 864             }
 865
 866             if (queues > 1 && i == 0 && !tap->has_ifname) {
 867                 if (tap_fd_get_ifname(fd, ifname)) {
 868                     error_report("Fail to get ifname");
 869                     close(fd);
 870                     return -1;
 871                 }
 872             }
 873
 874             net_init_tap_one(tap, peer, "tap", name, ifname,
 875                              i >= 1 ? "no" : script,
 876                              i >= 1 ? "no" : downscript,
 877                              vhostfdname, vnet_hdr, fd, &err);
 878             if (err) {
 879                 error_report_err(err);
 880                 close(fd);
 881                 return -1;
 882             }
 883         }
 884     }
 885
 886     return 0;
 887 }
 888
 889 VHostNetState *tap_get_vhost_net(NetClientState *nc)
 890 {
 891     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 892     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP);
 893     return s->vhost_net;
 894 }
 895
 896 int tap_enable(NetClientState *nc)
 897 {
 898     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 899     int ret;
 900
 901     if (s->enabled) {
 902         return 0;
 903     } else {
 904         ret = tap_fd_enable(s->fd);
 905         if (ret == 0) {
 906             s->enabled = true;
 907             tap_update_fd_handler(s);
 908         }
 909         return ret;
 910     }
 911 }
 912
 913 int tap_disable(NetClientState *nc)
 914 {
 915     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 916     int ret;
 917
 918     if (s->enabled == 0) {
 919         return 0;
 920     } else {
 921         ret = tap_fd_disable(s->fd);
 922         if (ret == 0) {
 923             qemu_purge_queued_packets(nc);
 924             s->enabled = false;
 925             tap_update_fd_handler(s);
 926         }
 927         return ret;
 928     }
 929 }