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