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/net.h"
  36 #include "clients.h"
  37 #include "monitor/monitor.h"
  38 #include "sysemu/sysemu.h"
  39 #include "qapi/error.h"
  40 #include "qemu-common.h"
  41 #include "qemu/cutils.h"
  42 #include "qemu/error-report.h"
  43
  44 #include "net/tap.h"
  45
  46 #include "net/vhost_net.h"
  47
  48 typedef struct TAPState {
  49     NetClientState nc;
  50     int fd;
  51     char down_script[1024];
  52     char down_script_arg[128];
  53     uint8_t buf[NET_BUFSIZE];
  54     bool read_poll;
  55     bool write_poll;
  56     bool using_vnet_hdr;
  57     bool has_ufo;
  58     bool enabled;
  59     VHostNetState *vhost_net;
  60     unsigned host_vnet_hdr_len;
  61     Notifier exit;
  62 } TAPState;
  63
  64 static void launch_script(const char *setup_script, const char *ifname,
  65                           int fd, Error **errp);
  66
  67 static void tap_send(void *opaque);
  68 static void tap_writable(void *opaque);
  69
  70 static void tap_update_fd_handler(TAPState *s)
  71 {
  72     qemu_set_fd_handler(s->fd,
  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 #ifndef __sun__
 170 ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen)
 171 {
 172     return read(tapfd, buf, maxlen);
 173 }
 174 #endif
 175
 176 static void tap_send_completed(NetClientState *nc, ssize_t len)
 177 {
 178     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 179     tap_read_poll(s, true);
 180 }
 181
 182 static void tap_send(void *opaque)
 183 {
 184     TAPState *s = opaque;
 185     int size;
 186     int packets = 0;
 187
 188     while (true) {
 189         uint8_t *buf = s->buf;
 190
 191         size = tap_read_packet(s->fd, s->buf, sizeof(s->buf));
 192         if (size <= 0) {
 193             break;
 194         }
 195
 196         if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
 197             buf  += s->host_vnet_hdr_len;
 198             size -= s->host_vnet_hdr_len;
 199         }
 200
 201         size = qemu_send_packet_async(&s->nc, buf, size, tap_send_completed);
 202         if (size == 0) {
 203             tap_read_poll(s, false);
 204             break;
 205         } else if (size < 0) {
 206             break;
 207         }
 208
 209         /*
 210          * When the host keeps receiving more packets while tap_send() is
 211          * running we can hog the QEMU global mutex.  Limit the number of
 212          * packets that are processed per tap_send() callback to prevent
 213          * stalling the guest.
 214          */
 215         packets++;
 216         if (packets >= 50) {
 217             break;
 218         }
 219     }
 220 }
 221
 222 static bool tap_has_ufo(NetClientState *nc)
 223 {
 224     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 225
 226     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 227
 228     return s->has_ufo;
 229 }
 230
 231 static bool tap_has_vnet_hdr(NetClientState *nc)
 232 {
 233     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 234
 235     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 236
 237     return !!s->host_vnet_hdr_len;
 238 }
 239
 240 static bool tap_has_vnet_hdr_len(NetClientState *nc, int len)
 241 {
 242     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 243
 244     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 245
 246     return !!tap_probe_vnet_hdr_len(s->fd, len);
 247 }
 248
 249 static void tap_set_vnet_hdr_len(NetClientState *nc, int len)
 250 {
 251     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 252
 253     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 254     assert(len == sizeof(struct virtio_net_hdr_mrg_rxbuf) ||
 255            len == sizeof(struct virtio_net_hdr));
 256
 257     tap_fd_set_vnet_hdr_len(s->fd, len);
 258     s->host_vnet_hdr_len = len;
 259 }
 260
 261 static void tap_using_vnet_hdr(NetClientState *nc, bool using_vnet_hdr)
 262 {
 263     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 264
 265     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 266     assert(!!s->host_vnet_hdr_len == using_vnet_hdr);
 267
 268     s->using_vnet_hdr = using_vnet_hdr;
 269 }
 270
 271 static int tap_set_vnet_le(NetClientState *nc, bool is_le)
 272 {
 273     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 274
 275     return tap_fd_set_vnet_le(s->fd, is_le);
 276 }
 277
 278 static int tap_set_vnet_be(NetClientState *nc, bool is_be)
 279 {
 280     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 281
 282     return tap_fd_set_vnet_be(s->fd, is_be);
 283 }
 284
 285 static void tap_set_offload(NetClientState *nc, int csum, int tso4,
 286                      int tso6, int ecn, int ufo)
 287 {
 288     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 289     if (s->fd < 0) {
 290         return;
 291     }
 292
 293     tap_fd_set_offload(s->fd, csum, tso4, tso6, ecn, ufo);
 294 }
 295
 296 static void tap_exit_notify(Notifier *notifier, void *data)
 297 {
 298     TAPState *s = container_of(notifier, TAPState, exit);
 299     Error *err = NULL;
 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
 309 static void tap_cleanup(NetClientState *nc)
 310 {
 311     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 312
 313     if (s->vhost_net) {
 314         vhost_net_cleanup(s->vhost_net);
 315         g_free(s->vhost_net);
 316         s->vhost_net = NULL;
 317     }
 318
 319     qemu_purge_queued_packets(nc);
 320
 321     tap_exit_notify(&s->exit, NULL);
 322     qemu_remove_exit_notifier(&s->exit);
 323
 324     tap_read_poll(s, false);
 325     tap_write_poll(s, false);
 326     close(s->fd);
 327     s->fd = -1;
 328 }
 329
 330 static void tap_poll(NetClientState *nc, bool enable)
 331 {
 332     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 333     tap_read_poll(s, enable);
 334     tap_write_poll(s, enable);
 335 }
 336
 337 int tap_get_fd(NetClientState *nc)
 338 {
 339     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 340     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 341     return s->fd;
 342 }
 343
 344 /* fd support */
 345
 346 static NetClientInfo net_tap_info = {
 347     .type = NET_CLIENT_DRIVER_TAP,
 348     .size = sizeof(TAPState),
 349     .receive = tap_receive,
 350     .receive_raw = tap_receive_raw,
 351     .receive_iov = tap_receive_iov,
 352     .poll = tap_poll,
 353     .cleanup = tap_cleanup,
 354     .has_ufo = tap_has_ufo,
 355     .has_vnet_hdr = tap_has_vnet_hdr,
 356     .has_vnet_hdr_len = tap_has_vnet_hdr_len,
 357     .using_vnet_hdr = tap_using_vnet_hdr,
 358     .set_offload = tap_set_offload,
 359     .set_vnet_hdr_len = tap_set_vnet_hdr_len,
 360     .set_vnet_le = tap_set_vnet_le,
 361     .set_vnet_be = tap_set_vnet_be,
 362 };
 363
 364 static TAPState *net_tap_fd_init(NetClientState *peer,
 365                                  const char *model,
 366                                  const char *name,
 367                                  int fd,
 368                                  int vnet_hdr)
 369 {
 370     NetClientState *nc;
 371     TAPState *s;
 372
 373     nc = qemu_new_net_client(&net_tap_info, peer, model, name);
 374
 375     s = DO_UPCAST(TAPState, nc, nc);
 376
 377     s->fd = fd;
 378     s->host_vnet_hdr_len = vnet_hdr ? sizeof(struct virtio_net_hdr) : 0;
 379     s->using_vnet_hdr = false;
 380     s->has_ufo = tap_probe_has_ufo(s->fd);
 381     s->enabled = true;
 382     tap_set_offload(&s->nc, 0, 0, 0, 0, 0);
 383     /*
 384      * Make sure host header length is set correctly in tap:
 385      * it might have been modified by another instance of qemu.
 386      */
 387     if (tap_probe_vnet_hdr_len(s->fd, s->host_vnet_hdr_len)) {
 388         tap_fd_set_vnet_hdr_len(s->fd, s->host_vnet_hdr_len);
 389     }
 390     tap_read_poll(s, true);
 391     s->vhost_net = NULL;
 392
 393     s->exit.notify = tap_exit_notify;
 394     qemu_add_exit_notifier(&s->exit);
 395
 396     return s;
 397 }
 398
 399 static void launch_script(const char *setup_script, const char *ifname,
 400                           int fd, Error **errp)
 401 {
 402     int pid, status;
 403     char *args[3];
 404     char **parg;
 405
 406     /* try to launch network script */
 407     pid = fork();
 408     if (pid < 0) {
 409         error_setg_errno(errp, errno, "could not launch network script %s",
 410                          setup_script);
 411         return;
 412     }
 413     if (pid == 0) {
 414         int open_max = sysconf(_SC_OPEN_MAX), i;
 415
 416         for (i = 3; i < open_max; i++) {
 417             if (i != fd) {
 418                 close(i);
 419             }
 420         }
 421         parg = args;
 422         *parg++ = (char *)setup_script;
 423         *parg++ = (char *)ifname;
 424         *parg = NULL;
 425         execv(setup_script, args);
 426         _exit(1);
 427     } else {
 428         while (waitpid(pid, &status, 0) != pid) {
 429             /* loop */
 430         }
 431
 432         if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
 433             return;
 434         }
 435         error_setg(errp, "network script %s failed with status %d",
 436                    setup_script, status);
 437     }
 438 }
 439
 440 static int recv_fd(int c)
 441 {
 442     int fd;
 443     uint8_t msgbuf[CMSG_SPACE(sizeof(fd))];
 444     struct msghdr msg = {
 445         .msg_control = msgbuf,
 446         .msg_controllen = sizeof(msgbuf),
 447     };
 448     struct cmsghdr *cmsg;
 449     struct iovec iov;
 450     uint8_t req[1];
 451     ssize_t len;
 452
 453     cmsg = CMSG_FIRSTHDR(&msg);
 454     cmsg->cmsg_level = SOL_SOCKET;
 455     cmsg->cmsg_type = SCM_RIGHTS;
 456     cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
 457     msg.msg_controllen = cmsg->cmsg_len;
 458
 459     iov.iov_base = req;
 460     iov.iov_len = sizeof(req);
 461
 462     msg.msg_iov = &iov;
 463     msg.msg_iovlen = 1;
 464
 465     len = recvmsg(c, &msg, 0);
 466     if (len > 0) {
 467         memcpy(&fd, CMSG_DATA(cmsg), sizeof(fd));
 468         return fd;
 469     }
 470
 471     return len;
 472 }
 473
 474 static int net_bridge_run_helper(const char *helper, const char *bridge,
 475                                  Error **errp)
 476 {
 477     sigset_t oldmask, mask;
 478     int pid, status;
 479     char *args[5];
 480     char **parg;
 481     int sv[2];
 482
 483     sigemptyset(&mask);
 484     sigaddset(&mask, SIGCHLD);
 485     sigprocmask(SIG_BLOCK, &mask, &oldmask);
 486
 487     if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) == -1) {
 488         error_setg_errno(errp, errno, "socketpair() failed");
 489         return -1;
 490     }
 491
 492     /* try to launch bridge helper */
 493     pid = fork();
 494     if (pid < 0) {
 495         error_setg_errno(errp, errno, "Can't fork bridge helper");
 496         return -1;
 497     }
 498     if (pid == 0) {
 499         int open_max = sysconf(_SC_OPEN_MAX), i;
 500         char fd_buf[6+10];
 501         char br_buf[6+IFNAMSIZ] = {0};
 502         char helper_cmd[PATH_MAX + sizeof(fd_buf) + sizeof(br_buf) + 15];
 503
 504         for (i = 3; i < open_max; i++) {
 505             if (i != sv[1]) {
 506                 close(i);
 507             }
 508         }
 509
 510         snprintf(fd_buf, sizeof(fd_buf), "%s%d", "--fd=", sv[1]);
 511
 512         if (strrchr(helper, ' ') || strrchr(helper, '\t')) {
 513             /* assume helper is a command */
 514
 515             if (strstr(helper, "--br=") == NULL) {
 516                 snprintf(br_buf, sizeof(br_buf), "%s%s", "--br=", bridge);
 517             }
 518
 519             snprintf(helper_cmd, sizeof(helper_cmd), "%s %s %s %s",
 520                      helper, "--use-vnet", fd_buf, br_buf);
 521
 522             parg = args;
 523             *parg++ = (char *)"sh";
 524             *parg++ = (char *)"-c";
 525             *parg++ = helper_cmd;
 526             *parg++ = NULL;
 527
 528             execv("/bin/sh", args);
 529         } else {
 530             /* assume helper is just the executable path name */
 531
 532             snprintf(br_buf, sizeof(br_buf), "%s%s", "--br=", bridge);
 533
 534             parg = args;
 535             *parg++ = (char *)helper;
 536             *parg++ = (char *)"--use-vnet";
 537             *parg++ = fd_buf;
 538             *parg++ = br_buf;
 539             *parg++ = NULL;
 540
 541             execv(helper, args);
 542         }
 543         _exit(1);
 544
 545     } else {
 546         int fd;
 547         int saved_errno;
 548
 549         close(sv[1]);
 550
 551         do {
 552             fd = recv_fd(sv[0]);
 553         } while (fd == -1 && errno == EINTR);
 554         saved_errno = errno;
 555
 556         close(sv[0]);
 557
 558         while (waitpid(pid, &status, 0) != pid) {
 559             /* loop */
 560         }
 561         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 562         if (fd < 0) {
 563             error_setg_errno(errp, saved_errno,
 564                              "failed to recv file descriptor");
 565             return -1;
 566         }
 567         if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 568             error_setg(errp, "bridge helper failed");
 569             return -1;
 570         }
 571         return fd;
 572     }
 573 }
 574
 575 int net_init_bridge(const Netdev *netdev, const char *name,
 576                     NetClientState *peer, Error **errp)
 577 {
 578     const NetdevBridgeOptions *bridge;
 579     const char *helper, *br;
 580     TAPState *s;
 581     int fd, vnet_hdr;
 582
 583     assert(netdev->type == NET_CLIENT_DRIVER_BRIDGE);
 584     bridge = &netdev->u.bridge;
 585
 586     helper = bridge->has_helper ? bridge->helper : DEFAULT_BRIDGE_HELPER;
 587     br     = bridge->has_br     ? bridge->br     : DEFAULT_BRIDGE_INTERFACE;
 588
 589     fd = net_bridge_run_helper(helper, br, errp);
 590     if (fd == -1) {
 591         return -1;
 592     }
 593
 594     fcntl(fd, F_SETFL, O_NONBLOCK);
 595     vnet_hdr = tap_probe_vnet_hdr(fd);
 596     s = net_tap_fd_init(peer, "bridge", name, fd, vnet_hdr);
 597
 598     snprintf(s->nc.info_str, sizeof(s->nc.info_str), "helper=%s,br=%s", helper,
 599              br);
 600
 601     return 0;
 602 }
 603
 604 static int net_tap_init(const NetdevTapOptions *tap, int *vnet_hdr,
 605                         const char *setup_script, char *ifname,
 606                         size_t ifname_sz, int mq_required, Error **errp)
 607 {
 608     Error *err = NULL;
 609     int fd, vnet_hdr_required;
 610
 611     if (tap->has_vnet_hdr) {
 612         *vnet_hdr = tap->vnet_hdr;
 613         vnet_hdr_required = *vnet_hdr;
 614     } else {
 615         *vnet_hdr = 1;
 616         vnet_hdr_required = 0;
 617     }
 618
 619     TFR(fd = tap_open(ifname, ifname_sz, vnet_hdr, vnet_hdr_required,
 620                       mq_required, errp));
 621     if (fd < 0) {
 622         return -1;
 623     }
 624
 625     if (setup_script &&
 626         setup_script[0] != '\0' &&
 627         strcmp(setup_script, "no") != 0) {
 628         launch_script(setup_script, ifname, fd, &err);
 629         if (err) {
 630             error_propagate(errp, err);
 631             close(fd);
 632             return -1;
 633         }
 634     }
 635
 636     return fd;
 637 }
 638
 639 #define MAX_TAP_QUEUES 1024
 640
 641 static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
 642                              const char *model, const char *name,
 643                              const char *ifname, const char *script,
 644                              const char *downscript, const char *vhostfdname,
 645                              int vnet_hdr, int fd, Error **errp)
 646 {
 647     Error *err = NULL;
 648     TAPState *s = net_tap_fd_init(peer, model, name, fd, vnet_hdr);
 649     int vhostfd;
 650
 651     tap_set_sndbuf(s->fd, tap, &err);
 652     if (err) {
 653         error_propagate(errp, err);
 654         return;
 655     }
 656
 657     if (tap->has_fd || tap->has_fds) {
 658         snprintf(s->nc.info_str, sizeof(s->nc.info_str), "fd=%d", fd);
 659     } else if (tap->has_helper) {
 660         snprintf(s->nc.info_str, sizeof(s->nc.info_str), "helper=%s",
 661                  tap->helper);
 662     } else {
 663         snprintf(s->nc.info_str, sizeof(s->nc.info_str),
 664                  "ifname=%s,script=%s,downscript=%s", ifname, script,
 665                  downscript);
 666
 667         if (strcmp(downscript, "no") != 0) {
 668             snprintf(s->down_script, sizeof(s->down_script), "%s", downscript);
 669             snprintf(s->down_script_arg, sizeof(s->down_script_arg),
 670                      "%s", ifname);
 671         }
 672     }
 673
 674     if (tap->has_vhost ? tap->vhost :
 675         vhostfdname || (tap->has_vhostforce && tap->vhostforce)) {
 676         VhostNetOptions options;
 677
 678         options.backend_type = VHOST_BACKEND_TYPE_KERNEL;
 679         options.net_backend = &s->nc;
 680         if (tap->has_poll_us) {
 681             options.busyloop_timeout = tap->poll_us;
 682         } else {
 683             options.busyloop_timeout = 0;
 684         }
 685
 686         if (vhostfdname) {
 687             vhostfd = monitor_fd_param(cur_mon, vhostfdname, &err);
 688             if (vhostfd == -1) {
 689                 error_propagate(errp, err);
 690                 return;
 691             }
 692         } else {
 693             vhostfd = open("/dev/vhost-net", O_RDWR);
 694             if (vhostfd < 0) {
 695                 error_setg_errno(errp, errno,
 696                                  "tap: open vhost char device failed");
 697                 return;
 698             }
 699             fcntl(vhostfd, F_SETFL, O_NONBLOCK);
 700         }
 701         options.opaque = (void *)(uintptr_t)vhostfd;
 702
 703         s->vhost_net = vhost_net_init(&options);
 704         if (!s->vhost_net) {
 705             error_setg(errp,
 706                        "vhost-net requested but could not be initialized");
 707             return;
 708         }
 709     } else if (vhostfdname) {
 710         error_setg(errp, "vhostfd(s)= is not valid without vhost");
 711     }
 712 }
 713
 714 static int get_fds(char *str, char *fds[], int max)
 715 {
 716     char *ptr = str, *this;
 717     size_t len = strlen(str);
 718     int i = 0;
 719
 720     while (i < max && ptr < str + len) {
 721         this = strchr(ptr, ':');
 722
 723         if (this == NULL) {
 724             fds[i] = g_strdup(ptr);
 725         } else {
 726             fds[i] = g_strndup(ptr, this - ptr);
 727         }
 728
 729         i++;
 730         if (this == NULL) {
 731             break;
 732         } else {
 733             ptr = this + 1;
 734         }
 735     }
 736
 737     return i;
 738 }
 739
 740 int net_init_tap(const Netdev *netdev, const char *name,
 741                  NetClientState *peer, Error **errp)
 742 {
 743     const NetdevTapOptions *tap;
 744     int fd, vnet_hdr = 0, i = 0, queues;
 745     /* for the no-fd, no-helper case */
 746     const char *script = NULL; /* suppress wrong "uninit'd use" gcc warning */
 747     const char *downscript = NULL;
 748     Error *err = NULL;
 749     const char *vhostfdname;
 750     char ifname[128];
 751
 752     assert(netdev->type == NET_CLIENT_DRIVER_TAP);
 753     tap = &netdev->u.tap;
 754     queues = tap->has_queues ? tap->queues : 1;
 755     vhostfdname = tap->has_vhostfd ? tap->vhostfd : NULL;
 756
 757     /* QEMU vlans does not support multiqueue tap, in this case peer is set.
 758      * For -netdev, peer is always NULL. */
 759     if (peer && (tap->has_queues || tap->has_fds || tap->has_vhostfds)) {
 760         error_setg(errp, "Multiqueue tap cannot be used with QEMU vlans");
 761         return -1;
 762     }
 763
 764     if (tap->has_fd) {
 765         if (tap->has_ifname || tap->has_script || tap->has_downscript ||
 766             tap->has_vnet_hdr || tap->has_helper || tap->has_queues ||
 767             tap->has_fds || tap->has_vhostfds) {
 768             error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
 769                        "helper=, queues=, fds=, and vhostfds= "
 770                        "are invalid with fd=");
 771             return -1;
 772         }
 773
 774         fd = monitor_fd_param(cur_mon, tap->fd, &err);
 775         if (fd == -1) {
 776             error_propagate(errp, err);
 777             return -1;
 778         }
 779
 780         fcntl(fd, F_SETFL, O_NONBLOCK);
 781
 782         vnet_hdr = tap_probe_vnet_hdr(fd);
 783
 784         net_init_tap_one(tap, peer, "tap", name, NULL,
 785                          script, downscript,
 786                          vhostfdname, vnet_hdr, fd, &err);
 787         if (err) {
 788             error_propagate(errp, err);
 789             return -1;
 790         }
 791     } else if (tap->has_fds) {
 792         char **fds;
 793         char **vhost_fds;
 794         int nfds, nvhosts;
 795
 796         if (tap->has_ifname || tap->has_script || tap->has_downscript ||
 797             tap->has_vnet_hdr || tap->has_helper || tap->has_queues ||
 798             tap->has_vhostfd) {
 799             error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
 800                        "helper=, queues=, and vhostfd= "
 801                        "are invalid with fds=");
 802             return -1;
 803         }
 804
 805         fds = g_new0(char *, MAX_TAP_QUEUES);
 806         vhost_fds = g_new0(char *, MAX_TAP_QUEUES);
 807
 808         nfds = get_fds(tap->fds, fds, MAX_TAP_QUEUES);
 809         if (tap->has_vhostfds) {
 810             nvhosts = get_fds(tap->vhostfds, vhost_fds, MAX_TAP_QUEUES);
 811             if (nfds != nvhosts) {
 812                 error_setg(errp, "The number of fds passed does not match "
 813                            "the number of vhostfds passed");
 814                 goto free_fail;
 815             }
 816         }
 817
 818         for (i = 0; i < nfds; i++) {
 819             fd = monitor_fd_param(cur_mon, fds[i], &err);
 820             if (fd == -1) {
 821                 error_propagate(errp, err);
 822                 goto free_fail;
 823             }
 824
 825             fcntl(fd, F_SETFL, O_NONBLOCK);
 826
 827             if (i == 0) {
 828                 vnet_hdr = tap_probe_vnet_hdr(fd);
 829             } else if (vnet_hdr != tap_probe_vnet_hdr(fd)) {
 830                 error_setg(errp,
 831                            "vnet_hdr not consistent across given tap fds");
 832                 goto free_fail;
 833             }
 834
 835             net_init_tap_one(tap, peer, "tap", name, ifname,
 836                              script, downscript,
 837                              tap->has_vhostfds ? vhost_fds[i] : NULL,
 838                              vnet_hdr, fd, &err);
 839             if (err) {
 840                 error_propagate(errp, err);
 841                 goto free_fail;
 842             }
 843         }
 844         g_free(fds);
 845         g_free(vhost_fds);
 846         return 0;
 847
 848 free_fail:
 849         for (i = 0; i < nfds; i++) {
 850             g_free(fds[i]);
 851             g_free(vhost_fds[i]);
 852         }
 853         g_free(fds);
 854         g_free(vhost_fds);
 855         return -1;
 856     } else if (tap->has_helper) {
 857         if (tap->has_ifname || tap->has_script || tap->has_downscript ||
 858             tap->has_vnet_hdr || tap->has_queues || tap->has_vhostfds) {
 859             error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
 860                        "queues=, and vhostfds= are invalid with helper=");
 861             return -1;
 862         }
 863
 864         fd = net_bridge_run_helper(tap->helper,
 865                                    tap->has_br ?
 866                                    tap->br : DEFAULT_BRIDGE_INTERFACE,
 867                                    errp);
 868         if (fd == -1) {
 869             return -1;
 870         }
 871
 872         fcntl(fd, F_SETFL, O_NONBLOCK);
 873         vnet_hdr = tap_probe_vnet_hdr(fd);
 874
 875         net_init_tap_one(tap, peer, "bridge", name, ifname,
 876                          script, downscript, vhostfdname,
 877                          vnet_hdr, fd, &err);
 878         if (err) {
 879             error_propagate(errp, err);
 880             close(fd);
 881             return -1;
 882         }
 883     } else {
 884         if (tap->has_vhostfds) {
 885             error_setg(errp, "vhostfds= is invalid if fds= wasn't specified");
 886             return -1;
 887         }
 888         script = tap->has_script ? tap->script : DEFAULT_NETWORK_SCRIPT;
 889         downscript = tap->has_downscript ? tap->downscript :
 890             DEFAULT_NETWORK_DOWN_SCRIPT;
 891
 892         if (tap->has_ifname) {
 893             pstrcpy(ifname, sizeof ifname, tap->ifname);
 894         } else {
 895             ifname[0] = '\0';
 896         }
 897
 898         for (i = 0; i < queues; i++) {
 899             fd = net_tap_init(tap, &vnet_hdr, i >= 1 ? "no" : script,
 900                               ifname, sizeof ifname, queues > 1, errp);
 901             if (fd == -1) {
 902                 return -1;
 903             }
 904
 905             if (queues > 1 && i == 0 && !tap->has_ifname) {
 906                 if (tap_fd_get_ifname(fd, ifname)) {
 907                     error_setg(errp, "Fail to get ifname");
 908                     close(fd);
 909                     return -1;
 910                 }
 911             }
 912
 913             net_init_tap_one(tap, peer, "tap", name, ifname,
 914                              i >= 1 ? "no" : script,
 915                              i >= 1 ? "no" : downscript,
 916                              vhostfdname, vnet_hdr, fd, &err);
 917             if (err) {
 918                 error_propagate(errp, err);
 919                 close(fd);
 920                 return -1;
 921             }
 922         }
 923     }
 924
 925     return 0;
 926 }
 927
 928 VHostNetState *tap_get_vhost_net(NetClientState *nc)
 929 {
 930     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 931     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 932     return s->vhost_net;
 933 }
 934
 935 int tap_enable(NetClientState *nc)
 936 {
 937     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 938     int ret;
 939
 940     if (s->enabled) {
 941         return 0;
 942     } else {
 943         ret = tap_fd_enable(s->fd);
 944         if (ret == 0) {
 945             s->enabled = true;
 946             tap_update_fd_handler(s);
 947         }
 948         return ret;
 949     }
 950 }
 951
 952 int tap_disable(NetClientState *nc)
 953 {
 954     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 955     int ret;
 956
 957     if (s->enabled == 0) {
 958         return 0;
 959     } else {
 960         ret = tap_fd_disable(s->fd);
 961         if (ret == 0) {
 962             qemu_purge_queued_packets(nc);
 963             s->enabled = false;
 964             tap_update_fd_handler(s);
 965         }
 966         return ret;
 967     }
 968 }