net/tap.c

   1 /*
   2  * QEMU System Emulator
   3  *
   4  * Copyright (c) 2003-2008 Fabrice Bellard
   5  * Copyright (c) 2009 Red Hat, Inc.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  */
  25
  26 #include "qemu/osdep.h"
  27 #include "tap_int.h"
  28
  29
  30 #include <sys/ioctl.h>
  31 #include <sys/wait.h>
  32 #include <sys/socket.h>
  33 #include <net/if.h>
  34
  35 #include "net/eth.h"
  36 #include "net/net.h"
  37 #include "clients.h"
  38 #include "monitor/monitor.h"
  39 #include "sysemu/sysemu.h"
  40 #include "qapi/error.h"
  41 #include "qemu/cutils.h"
  42 #include "qemu/error-report.h"
  43 #include "qemu/main-loop.h"
  44 #include "qemu/sockets.h"
  45
  46 #include "net/tap.h"
  47
  48 #include "net/vhost_net.h"
  49
  50 typedef struct TAPState {
  51     NetClientState nc;
  52     int fd;
  53     char down_script[1024];
  54     char down_script_arg[128];
  55     uint8_t buf[NET_BUFSIZE];
  56     bool read_poll;
  57     bool write_poll;
  58     bool using_vnet_hdr;
  59     bool has_ufo;
  60     bool enabled;
  61     VHostNetState *vhost_net;
  62     unsigned host_vnet_hdr_len;
  63     Notifier exit;
  64 } TAPState;
  65
  66 static void launch_script(const char *setup_script, const char *ifname,
  67                           int fd, Error **errp);
  68
  69 static void tap_send(void *opaque);
  70 static void tap_writable(void *opaque);
  71
  72 static void tap_update_fd_handler(TAPState *s)
  73 {
  74     qemu_set_fd_handler(s->fd,
  75                         s->read_poll && s->enabled ? tap_send : NULL,
  76                         s->write_poll && s->enabled ? tap_writable : NULL,
  77                         s);
  78 }
  79
  80 static void tap_read_poll(TAPState *s, bool enable)
  81 {
  82     s->read_poll = enable;
  83     tap_update_fd_handler(s);
  84 }
  85
  86 static void tap_write_poll(TAPState *s, bool enable)
  87 {
  88     s->write_poll = enable;
  89     tap_update_fd_handler(s);
  90 }
  91
  92 static void tap_writable(void *opaque)
  93 {
  94     TAPState *s = opaque;
  95
  96     tap_write_poll(s, false);
  97
  98     qemu_flush_queued_packets(&s->nc);
  99 }
 100
 101 static ssize_t tap_write_packet(TAPState *s, const struct iovec *iov, int iovcnt)
 102 {
 103     ssize_t len;
 104
 105     len = RETRY_ON_EINTR(writev(s->fd, iov, iovcnt));
 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         uint8_t min_pkt[ETH_ZLEN];
 191         size_t min_pktsz = sizeof(min_pkt);
 192
 193         size = tap_read_packet(s->fd, s->buf, sizeof(s->buf));
 194         if (size <= 0) {
 195             break;
 196         }
 197
 198         if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
 199             buf  += s->host_vnet_hdr_len;
 200             size -= s->host_vnet_hdr_len;
 201         }
 202
 203         if (net_peer_needs_padding(&s->nc)) {
 204             if (eth_pad_short_frame(min_pkt, &min_pktsz, buf, size)) {
 205                 buf = min_pkt;
 206                 size = min_pktsz;
 207             }
 208         }
 209
 210         size = qemu_send_packet_async(&s->nc, buf, size, tap_send_completed);
 211         if (size == 0) {
 212             tap_read_poll(s, false);
 213             break;
 214         } else if (size < 0) {
 215             break;
 216         }
 217
 218         /*
 219          * When the host keeps receiving more packets while tap_send() is
 220          * running we can hog the QEMU global mutex.  Limit the number of
 221          * packets that are processed per tap_send() callback to prevent
 222          * stalling the guest.
 223          */
 224         packets++;
 225         if (packets >= 50) {
 226             break;
 227         }
 228     }
 229 }
 230
 231 static bool tap_has_ufo(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->has_ufo;
 238 }
 239
 240 static bool tap_has_vnet_hdr(NetClientState *nc)
 241 {
 242     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 243
 244     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 245
 246     return !!s->host_vnet_hdr_len;
 247 }
 248
 249 static bool tap_has_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
 255     return !!tap_probe_vnet_hdr_len(s->fd, len);
 256 }
 257
 258 static void tap_set_vnet_hdr_len(NetClientState *nc, int len)
 259 {
 260     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 261
 262     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 263     assert(len == sizeof(struct virtio_net_hdr_mrg_rxbuf) ||
 264            len == sizeof(struct virtio_net_hdr) ||
 265            len == sizeof(struct virtio_net_hdr_v1_hash));
 266
 267     tap_fd_set_vnet_hdr_len(s->fd, len);
 268     s->host_vnet_hdr_len = len;
 269 }
 270
 271 static void tap_using_vnet_hdr(NetClientState *nc, bool using_vnet_hdr)
 272 {
 273     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 274
 275     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 276     assert(!!s->host_vnet_hdr_len == using_vnet_hdr);
 277
 278     s->using_vnet_hdr = using_vnet_hdr;
 279 }
 280
 281 static int tap_set_vnet_le(NetClientState *nc, bool is_le)
 282 {
 283     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 284
 285     return tap_fd_set_vnet_le(s->fd, is_le);
 286 }
 287
 288 static int tap_set_vnet_be(NetClientState *nc, bool is_be)
 289 {
 290     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 291
 292     return tap_fd_set_vnet_be(s->fd, is_be);
 293 }
 294
 295 static void tap_set_offload(NetClientState *nc, int csum, int tso4,
 296                      int tso6, int ecn, int ufo)
 297 {
 298     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 299     if (s->fd < 0) {
 300         return;
 301     }
 302
 303     tap_fd_set_offload(s->fd, csum, tso4, tso6, ecn, ufo);
 304 }
 305
 306 static void tap_exit_notify(Notifier *notifier, void *data)
 307 {
 308     TAPState *s = container_of(notifier, TAPState, exit);
 309     Error *err = NULL;
 310
 311     if (s->down_script[0]) {
 312         launch_script(s->down_script, s->down_script_arg, s->fd, &err);
 313         if (err) {
 314             error_report_err(err);
 315         }
 316     }
 317 }
 318
 319 static void tap_cleanup(NetClientState *nc)
 320 {
 321     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 322
 323     if (s->vhost_net) {
 324         vhost_net_cleanup(s->vhost_net);
 325         g_free(s->vhost_net);
 326         s->vhost_net = NULL;
 327     }
 328
 329     qemu_purge_queued_packets(nc);
 330
 331     tap_exit_notify(&s->exit, NULL);
 332     qemu_remove_exit_notifier(&s->exit);
 333
 334     tap_read_poll(s, false);
 335     tap_write_poll(s, false);
 336     close(s->fd);
 337     s->fd = -1;
 338 }
 339
 340 static void tap_poll(NetClientState *nc, bool enable)
 341 {
 342     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 343     tap_read_poll(s, enable);
 344     tap_write_poll(s, enable);
 345 }
 346
 347 static bool tap_set_steering_ebpf(NetClientState *nc, int prog_fd)
 348 {
 349     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 350     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 351
 352     return tap_fd_set_steering_ebpf(s->fd, prog_fd) == 0;
 353 }
 354
 355 int tap_get_fd(NetClientState *nc)
 356 {
 357     TAPState *s = DO_UPCAST(TAPState, nc, nc);
 358     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 359     return s->fd;
 360 }
 361
 362 /* fd support */
 363
 364 static NetClientInfo net_tap_info = {
 365     .type = NET_CLIENT_DRIVER_TAP,
 366     .size = sizeof(TAPState),
 367     .receive = tap_receive,
 368     .receive_raw = tap_receive_raw,
 369     .receive_iov = tap_receive_iov,
 370     .poll = tap_poll,
 371     .cleanup = tap_cleanup,
 372     .has_ufo = tap_has_ufo,
 373     .has_vnet_hdr = tap_has_vnet_hdr,
 374     .has_vnet_hdr_len = tap_has_vnet_hdr_len,
 375     .using_vnet_hdr = tap_using_vnet_hdr,
 376     .set_offload = tap_set_offload,
 377     .set_vnet_hdr_len = tap_set_vnet_hdr_len,
 378     .set_vnet_le = tap_set_vnet_le,
 379     .set_vnet_be = tap_set_vnet_be,
 380     .set_steering_ebpf = tap_set_steering_ebpf,
 381 };
 382
 383 static TAPState *net_tap_fd_init(NetClientState *peer,
 384                                  const char *model,
 385                                  const char *name,
 386                                  int fd,
 387                                  int vnet_hdr)
 388 {
 389     NetClientState *nc;
 390     TAPState *s;
 391
 392     nc = qemu_new_net_client(&net_tap_info, peer, model, name);
 393
 394     s = DO_UPCAST(TAPState, nc, nc);
 395
 396     s->fd = fd;
 397     s->host_vnet_hdr_len = vnet_hdr ? sizeof(struct virtio_net_hdr) : 0;
 398     s->using_vnet_hdr = false;
 399     s->has_ufo = tap_probe_has_ufo(s->fd);
 400     s->enabled = true;
 401     tap_set_offload(&s->nc, 0, 0, 0, 0, 0);
 402     /*
 403      * Make sure host header length is set correctly in tap:
 404      * it might have been modified by another instance of qemu.
 405      */
 406     if (tap_probe_vnet_hdr_len(s->fd, s->host_vnet_hdr_len)) {
 407         tap_fd_set_vnet_hdr_len(s->fd, s->host_vnet_hdr_len);
 408     }
 409     tap_read_poll(s, true);
 410     s->vhost_net = NULL;
 411
 412     s->exit.notify = tap_exit_notify;
 413     qemu_add_exit_notifier(&s->exit);
 414
 415     return s;
 416 }
 417
 418 static void launch_script(const char *setup_script, const char *ifname,
 419                           int fd, Error **errp)
 420 {
 421     int pid, status;
 422     char *args[3];
 423     char **parg;
 424
 425     /* try to launch network script */
 426     pid = fork();
 427     if (pid < 0) {
 428         error_setg_errno(errp, errno, "could not launch network script %s",
 429                          setup_script);
 430         return;
 431     }
 432     if (pid == 0) {
 433         int open_max = sysconf(_SC_OPEN_MAX), i;
 434
 435         for (i = 3; i < open_max; i++) {
 436             if (i != fd) {
 437                 close(i);
 438             }
 439         }
 440         parg = args;
 441         *parg++ = (char *)setup_script;
 442         *parg++ = (char *)ifname;
 443         *parg = NULL;
 444         execv(setup_script, args);
 445         _exit(1);
 446     } else {
 447         while (waitpid(pid, &status, 0) != pid) {
 448             /* loop */
 449         }
 450
 451         if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
 452             return;
 453         }
 454         error_setg(errp, "network script %s failed with status %d",
 455                    setup_script, status);
 456     }
 457 }
 458
 459 static int recv_fd(int c)
 460 {
 461     int fd;
 462     uint8_t msgbuf[CMSG_SPACE(sizeof(fd))];
 463     struct msghdr msg = {
 464         .msg_control = msgbuf,
 465         .msg_controllen = sizeof(msgbuf),
 466     };
 467     struct cmsghdr *cmsg;
 468     struct iovec iov;
 469     uint8_t req[1];
 470     ssize_t len;
 471
 472     cmsg = CMSG_FIRSTHDR(&msg);
 473     cmsg->cmsg_level = SOL_SOCKET;
 474     cmsg->cmsg_type = SCM_RIGHTS;
 475     cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
 476     msg.msg_controllen = cmsg->cmsg_len;
 477
 478     iov.iov_base = req;
 479     iov.iov_len = sizeof(req);
 480
 481     msg.msg_iov = &iov;
 482     msg.msg_iovlen = 1;
 483
 484     len = recvmsg(c, &msg, 0);
 485     if (len > 0) {
 486         memcpy(&fd, CMSG_DATA(cmsg), sizeof(fd));
 487         return fd;
 488     }
 489
 490     return len;
 491 }
 492
 493 static int net_bridge_run_helper(const char *helper, const char *bridge,
 494                                  Error **errp)
 495 {
 496     sigset_t oldmask, mask;
 497     g_autofree char *default_helper = NULL;
 498     int pid, status;
 499     char *args[5];
 500     char **parg;
 501     int sv[2];
 502
 503     sigemptyset(&mask);
 504     sigaddset(&mask, SIGCHLD);
 505     sigprocmask(SIG_BLOCK, &mask, &oldmask);
 506
 507     if (!helper) {
 508         helper = default_helper = get_relocated_path(DEFAULT_BRIDGE_HELPER);
 509     }
 510
 511     if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) == -1) {
 512         error_setg_errno(errp, errno, "socketpair() failed");
 513         return -1;
 514     }
 515
 516     /* try to launch bridge helper */
 517     pid = fork();
 518     if (pid < 0) {
 519         error_setg_errno(errp, errno, "Can't fork bridge helper");
 520         return -1;
 521     }
 522     if (pid == 0) {
 523         int open_max = sysconf(_SC_OPEN_MAX), i;
 524         char *fd_buf = NULL;
 525         char *br_buf = NULL;
 526         char *helper_cmd = NULL;
 527
 528         for (i = 3; i < open_max; i++) {
 529             if (i != sv[1]) {
 530                 close(i);
 531             }
 532         }
 533
 534         fd_buf = g_strdup_printf("%s%d", "--fd=", sv[1]);
 535
 536         if (strrchr(helper, ' ') || strrchr(helper, '\t')) {
 537             /* assume helper is a command */
 538
 539             if (strstr(helper, "--br=") == NULL) {
 540                 br_buf = g_strdup_printf("%s%s", "--br=", bridge);
 541             }
 542
 543             helper_cmd = g_strdup_printf("%s %s %s %s", helper,
 544                             "--use-vnet", fd_buf, br_buf ? br_buf : "");
 545
 546             parg = args;
 547             *parg++ = (char *)"sh";
 548             *parg++ = (char *)"-c";
 549             *parg++ = helper_cmd;
 550             *parg++ = NULL;
 551
 552             execv("/bin/sh", args);
 553             g_free(helper_cmd);
 554         } else {
 555             /* assume helper is just the executable path name */
 556
 557             br_buf = g_strdup_printf("%s%s", "--br=", bridge);
 558
 559             parg = args;
 560             *parg++ = (char *)helper;
 561             *parg++ = (char *)"--use-vnet";
 562             *parg++ = fd_buf;
 563             *parg++ = br_buf;
 564             *parg++ = NULL;
 565
 566             execv(helper, args);
 567         }
 568         g_free(fd_buf);
 569         g_free(br_buf);
 570         _exit(1);
 571
 572     } else {
 573         int fd;
 574         int saved_errno;
 575
 576         close(sv[1]);
 577
 578         fd = RETRY_ON_EINTR(recv_fd(sv[0]));
 579         saved_errno = errno;
 580
 581         close(sv[0]);
 582
 583         while (waitpid(pid, &status, 0) != pid) {
 584             /* loop */
 585         }
 586         sigprocmask(SIG_SETMASK, &oldmask, NULL);
 587         if (fd < 0) {
 588             error_setg_errno(errp, saved_errno,
 589                              "failed to recv file descriptor");
 590             return -1;
 591         }
 592         if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 593             error_setg(errp, "bridge helper failed");
 594             return -1;
 595         }
 596         return fd;
 597     }
 598 }
 599
 600 int net_init_bridge(const Netdev *netdev, const char *name,
 601                     NetClientState *peer, Error **errp)
 602 {
 603     const NetdevBridgeOptions *bridge;
 604     const char *helper, *br;
 605     TAPState *s;
 606     int fd, vnet_hdr;
 607
 608     assert(netdev->type == NET_CLIENT_DRIVER_BRIDGE);
 609     bridge = &netdev->u.bridge;
 610     helper = bridge->helper;
 611     br     = bridge->br ?: DEFAULT_BRIDGE_INTERFACE;
 612
 613     fd = net_bridge_run_helper(helper, br, errp);
 614     if (fd == -1) {
 615         return -1;
 616     }
 617
 618     if (!g_unix_set_fd_nonblocking(fd, true, NULL)) {
 619         error_setg_errno(errp, errno, "Failed to set FD nonblocking");
 620         return -1;
 621     }
 622     vnet_hdr = tap_probe_vnet_hdr(fd, errp);
 623     if (vnet_hdr < 0) {
 624         close(fd);
 625         return -1;
 626     }
 627     s = net_tap_fd_init(peer, "bridge", name, fd, vnet_hdr);
 628
 629     qemu_set_info_str(&s->nc, "helper=%s,br=%s", helper, br);
 630
 631     return 0;
 632 }
 633
 634 static int net_tap_init(const NetdevTapOptions *tap, int *vnet_hdr,
 635                         const char *setup_script, char *ifname,
 636                         size_t ifname_sz, int mq_required, Error **errp)
 637 {
 638     Error *err = NULL;
 639     int fd, vnet_hdr_required;
 640
 641     if (tap->has_vnet_hdr) {
 642         *vnet_hdr = tap->vnet_hdr;
 643         vnet_hdr_required = *vnet_hdr;
 644     } else {
 645         *vnet_hdr = 1;
 646         vnet_hdr_required = 0;
 647     }
 648
 649     fd = RETRY_ON_EINTR(tap_open(ifname, ifname_sz, vnet_hdr, vnet_hdr_required,
 650                       mq_required, errp));
 651     if (fd < 0) {
 652         return -1;
 653     }
 654
 655     if (setup_script &&
 656         setup_script[0] != '\0' &&
 657         strcmp(setup_script, "no") != 0) {
 658         launch_script(setup_script, ifname, fd, &err);
 659         if (err) {
 660             error_propagate(errp, err);
 661             close(fd);
 662             return -1;
 663         }
 664     }
 665
 666     return fd;
 667 }
 668
 669 #define MAX_TAP_QUEUES 1024
 670
 671 static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
 672                              const char *model, const char *name,
 673                              const char *ifname, const char *script,
 674                              const char *downscript, const char *vhostfdname,
 675                              int vnet_hdr, int fd, Error **errp)
 676 {
 677     Error *err = NULL;
 678     TAPState *s = net_tap_fd_init(peer, model, name, fd, vnet_hdr);
 679     int vhostfd;
 680
 681     tap_set_sndbuf(s->fd, tap, &err);
 682     if (err) {
 683         error_propagate(errp, err);
 684         goto failed;
 685     }
 686
 687     if (tap->fd || tap->fds) {
 688         qemu_set_info_str(&s->nc, "fd=%d", fd);
 689     } else if (tap->helper) {
 690         qemu_set_info_str(&s->nc, "helper=%s", tap->helper);
 691     } else {
 692         qemu_set_info_str(&s->nc, "ifname=%s,script=%s,downscript=%s", ifname,
 693                           script, downscript);
 694
 695         if (strcmp(downscript, "no") != 0) {
 696             snprintf(s->down_script, sizeof(s->down_script), "%s", downscript);
 697             snprintf(s->down_script_arg, sizeof(s->down_script_arg),
 698                      "%s", ifname);
 699         }
 700     }
 701
 702     if (tap->has_vhost ? tap->vhost :
 703         vhostfdname || (tap->has_vhostforce && tap->vhostforce)) {
 704         VhostNetOptions options;
 705
 706         options.backend_type = VHOST_BACKEND_TYPE_KERNEL;
 707         options.net_backend = &s->nc;
 708         if (tap->has_poll_us) {
 709             options.busyloop_timeout = tap->poll_us;
 710         } else {
 711             options.busyloop_timeout = 0;
 712         }
 713
 714         if (vhostfdname) {
 715             vhostfd = monitor_fd_param(monitor_cur(), vhostfdname, &err);
 716             if (vhostfd == -1) {
 717                 if (tap->has_vhostforce && tap->vhostforce) {
 718                     error_propagate(errp, err);
 719                 } else {
 720                     warn_report_err(err);
 721                 }
 722                 goto failed;
 723             }
 724             if (!g_unix_set_fd_nonblocking(vhostfd, true, NULL)) {
 725                 error_setg_errno(errp, errno, "%s: Can't use file descriptor %d",
 726                                  name, fd);
 727                 goto failed;
 728             }
 729         } else {
 730             vhostfd = open("/dev/vhost-net", O_RDWR);
 731             if (vhostfd < 0) {
 732                 if (tap->has_vhostforce && tap->vhostforce) {
 733                     error_setg_errno(errp, errno,
 734                                      "tap: open vhost char device failed");
 735                 } else {
 736                     warn_report("tap: open vhost char device failed: %s",
 737                                 strerror(errno));
 738                 }
 739                 goto failed;
 740             }
 741             if (!g_unix_set_fd_nonblocking(vhostfd, true, NULL)) {
 742                 error_setg_errno(errp, errno, "Failed to set FD nonblocking");
 743                 goto failed;
 744             }
 745         }
 746         options.opaque = (void *)(uintptr_t)vhostfd;
 747         options.nvqs = 2;
 748
 749         s->vhost_net = vhost_net_init(&options);
 750         if (!s->vhost_net) {
 751             if (tap->has_vhostforce && tap->vhostforce) {
 752                 error_setg(errp, VHOST_NET_INIT_FAILED);
 753             } else {
 754                 warn_report(VHOST_NET_INIT_FAILED);
 755             }
 756             goto failed;
 757         }
 758     } else if (vhostfdname) {
 759         error_setg(errp, "vhostfd(s)= is not valid without vhost");
 760         goto failed;
 761     }
 762
 763     return;
 764
 765 failed:
 766     qemu_del_net_client(&s->nc);
 767 }
 768
 769 static int get_fds(char *str, char *fds[], int max)
 770 {
 771     char *ptr = str, *this;
 772     size_t len = strlen(str);
 773     int i = 0;
 774
 775     while (i < max && ptr < str + len) {
 776         this = strchr(ptr, ':');
 777
 778         if (this == NULL) {
 779             fds[i] = g_strdup(ptr);
 780         } else {
 781             fds[i] = g_strndup(ptr, this - ptr);
 782         }
 783
 784         i++;
 785         if (this == NULL) {
 786             break;
 787         } else {
 788             ptr = this + 1;
 789         }
 790     }
 791
 792     return i;
 793 }
 794
 795 int net_init_tap(const Netdev *netdev, const char *name,
 796                  NetClientState *peer, Error **errp)
 797 {
 798     const NetdevTapOptions *tap;
 799     int fd, vnet_hdr = 0, i = 0, queues;
 800     /* for the no-fd, no-helper case */
 801     const char *script;
 802     const char *downscript;
 803     Error *err = NULL;
 804     const char *vhostfdname;
 805     char ifname[128];
 806     int ret = 0;
 807
 808     assert(netdev->type == NET_CLIENT_DRIVER_TAP);
 809     tap = &netdev->u.tap;
 810     queues = tap->has_queues ? tap->queues : 1;
 811     vhostfdname = tap->vhostfd;
 812     script = tap->script;
 813     downscript = tap->downscript;
 814
 815     /* QEMU hubs do not support multiqueue tap, in this case peer is set.
 816      * For -netdev, peer is always NULL. */
 817     if (peer && (tap->has_queues || tap->fds || tap->vhostfds)) {
 818         error_setg(errp, "Multiqueue tap cannot be used with hubs");
 819         return -1;
 820     }
 821
 822     if (tap->fd) {
 823         if (tap->ifname || tap->script || tap->downscript ||
 824             tap->has_vnet_hdr || tap->helper || tap->has_queues ||
 825             tap->fds || tap->vhostfds) {
 826             error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
 827                        "helper=, queues=, fds=, and vhostfds= "
 828                        "are invalid with fd=");
 829             return -1;
 830         }
 831
 832         fd = monitor_fd_param(monitor_cur(), tap->fd, errp);
 833         if (fd == -1) {
 834             return -1;
 835         }
 836
 837         if (!g_unix_set_fd_nonblocking(fd, true, NULL)) {
 838             error_setg_errno(errp, errno, "%s: Can't use file descriptor %d",
 839                              name, fd);
 840             close(fd);
 841             return -1;
 842         }
 843
 844         vnet_hdr = tap_probe_vnet_hdr(fd, errp);
 845         if (vnet_hdr < 0) {
 846             close(fd);
 847             return -1;
 848         }
 849
 850         net_init_tap_one(tap, peer, "tap", name, NULL,
 851                          script, downscript,
 852                          vhostfdname, vnet_hdr, fd, &err);
 853         if (err) {
 854             error_propagate(errp, err);
 855             close(fd);
 856             return -1;
 857         }
 858     } else if (tap->fds) {
 859         char **fds;
 860         char **vhost_fds;
 861         int nfds = 0, nvhosts = 0;
 862
 863         if (tap->ifname || tap->script || tap->downscript ||
 864             tap->has_vnet_hdr || tap->helper || tap->has_queues ||
 865             tap->vhostfd) {
 866             error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
 867                        "helper=, queues=, and vhostfd= "
 868                        "are invalid with fds=");
 869             return -1;
 870         }
 871
 872         fds = g_new0(char *, MAX_TAP_QUEUES);
 873         vhost_fds = g_new0(char *, MAX_TAP_QUEUES);
 874
 875         nfds = get_fds(tap->fds, fds, MAX_TAP_QUEUES);
 876         if (tap->vhostfds) {
 877             nvhosts = get_fds(tap->vhostfds, vhost_fds, MAX_TAP_QUEUES);
 878             if (nfds != nvhosts) {
 879                 error_setg(errp, "The number of fds passed does not match "
 880                            "the number of vhostfds passed");
 881                 ret = -1;
 882                 goto free_fail;
 883             }
 884         }
 885
 886         for (i = 0; i < nfds; i++) {
 887             fd = monitor_fd_param(monitor_cur(), fds[i], errp);
 888             if (fd == -1) {
 889                 ret = -1;
 890                 goto free_fail;
 891             }
 892
 893             ret = g_unix_set_fd_nonblocking(fd, true, NULL);
 894             if (!ret) {
 895                 error_setg_errno(errp, errno, "%s: Can't use file descriptor %d",
 896                                  name, fd);
 897                 goto free_fail;
 898             }
 899
 900             if (i == 0) {
 901                 vnet_hdr = tap_probe_vnet_hdr(fd, errp);
 902                 if (vnet_hdr < 0) {
 903                     ret = -1;
 904                     goto free_fail;
 905                 }
 906             } else if (vnet_hdr != tap_probe_vnet_hdr(fd, NULL)) {
 907                 error_setg(errp,
 908                            "vnet_hdr not consistent across given tap fds");
 909                 ret = -1;
 910                 goto free_fail;
 911             }
 912
 913             net_init_tap_one(tap, peer, "tap", name, ifname,
 914                              script, downscript,
 915                              tap->vhostfds ? vhost_fds[i] : NULL,
 916                              vnet_hdr, fd, &err);
 917             if (err) {
 918                 error_propagate(errp, err);
 919                 ret = -1;
 920                 goto free_fail;
 921             }
 922         }
 923
 924 free_fail:
 925         for (i = 0; i < nvhosts; i++) {
 926             g_free(vhost_fds[i]);
 927         }
 928         for (i = 0; i < nfds; i++) {
 929             g_free(fds[i]);
 930         }
 931         g_free(fds);
 932         g_free(vhost_fds);
 933         return ret;
 934     } else if (tap->helper) {
 935         if (tap->ifname || tap->script || tap->downscript ||
 936             tap->has_vnet_hdr || tap->has_queues || tap->vhostfds) {
 937             error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
 938                        "queues=, and vhostfds= are invalid with helper=");
 939             return -1;
 940         }
 941
 942         fd = net_bridge_run_helper(tap->helper,
 943                                    tap->br ?: DEFAULT_BRIDGE_INTERFACE,
 944                                    errp);
 945         if (fd == -1) {
 946             return -1;
 947         }
 948
 949         if (!g_unix_set_fd_nonblocking(fd, true, NULL)) {
 950             error_setg_errno(errp, errno, "Failed to set FD nonblocking");
 951             return -1;
 952         }
 953         vnet_hdr = tap_probe_vnet_hdr(fd, errp);
 954         if (vnet_hdr < 0) {
 955             close(fd);
 956             return -1;
 957         }
 958
 959         net_init_tap_one(tap, peer, "bridge", name, ifname,
 960                          script, downscript, vhostfdname,
 961                          vnet_hdr, fd, &err);
 962         if (err) {
 963             error_propagate(errp, err);
 964             close(fd);
 965             return -1;
 966         }
 967     } else {
 968         g_autofree char *default_script = NULL;
 969         g_autofree char *default_downscript = NULL;
 970         if (tap->vhostfds) {
 971             error_setg(errp, "vhostfds= is invalid if fds= wasn't specified");
 972             return -1;
 973         }
 974
 975         if (!script) {
 976             script = default_script = get_relocated_path(DEFAULT_NETWORK_SCRIPT);
 977         }
 978         if (!downscript) {
 979             downscript = default_downscript =
 980                                  get_relocated_path(DEFAULT_NETWORK_DOWN_SCRIPT);
 981         }
 982
 983         if (tap->ifname) {
 984             pstrcpy(ifname, sizeof ifname, tap->ifname);
 985         } else {
 986             ifname[0] = '\0';
 987         }
 988
 989         for (i = 0; i < queues; i++) {
 990             fd = net_tap_init(tap, &vnet_hdr, i >= 1 ? "no" : script,
 991                               ifname, sizeof ifname, queues > 1, errp);
 992             if (fd == -1) {
 993                 return -1;
 994             }
 995
 996             if (queues > 1 && i == 0 && !tap->ifname) {
 997                 if (tap_fd_get_ifname(fd, ifname)) {
 998                     error_setg(errp, "Fail to get ifname");
 999                     close(fd);
1000                     return -1;
1001                 }
1002             }
1003
1004             net_init_tap_one(tap, peer, "tap", name, ifname,
1005                              i >= 1 ? "no" : script,
1006                              i >= 1 ? "no" : downscript,
1007                              vhostfdname, vnet_hdr, fd, &err);
1008             if (err) {
1009                 error_propagate(errp, err);
1010                 close(fd);
1011                 return -1;
1012             }
1013         }
1014     }
1015
1016     return 0;
1017 }
1018
1019 VHostNetState *tap_get_vhost_net(NetClientState *nc)
1020 {
1021     TAPState *s = DO_UPCAST(TAPState, nc, nc);
1022     assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
1023     return s->vhost_net;
1024 }
1025
1026 int tap_enable(NetClientState *nc)
1027 {
1028     TAPState *s = DO_UPCAST(TAPState, nc, nc);
1029     int ret;
1030
1031     if (s->enabled) {
1032         return 0;
1033     } else {
1034         ret = tap_fd_enable(s->fd);
1035         if (ret == 0) {
1036             s->enabled = true;
1037             tap_update_fd_handler(s);
1038         }
1039         return ret;
1040     }
1041 }
1042
1043 int tap_disable(NetClientState *nc)
1044 {
1045     TAPState *s = DO_UPCAST(TAPState, nc, nc);
1046     int ret;
1047
1048     if (s->enabled == 0) {
1049         return 0;
1050     } else {
1051         ret = tap_fd_disable(s->fd);
1052         if (ret == 0) {
1053             qemu_purge_queued_packets(nc);
1054             s->enabled = false;
1055             tap_update_fd_handler(s);
1056         }
1057         return ret;
1058     }
1059 }