qemu/net/tap.c
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   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#include "qemu/sockets.h"
  44
  45#include "net/tap.h"
  46
  47#include "net/vhost_net.h"
  48
  49typedef struct TAPState {
  50    NetClientState nc;
  51    int fd;
  52    char down_script[1024];
  53    char down_script_arg[128];
  54    uint8_t buf[NET_BUFSIZE];
  55    bool read_poll;
  56    bool write_poll;
  57    bool using_vnet_hdr;
  58    bool has_ufo;
  59    bool enabled;
  60    VHostNetState *vhost_net;
  61    unsigned host_vnet_hdr_len;
  62    Notifier exit;
  63} TAPState;
  64
  65static void launch_script(const char *setup_script, const char *ifname,
  66                          int fd, Error **errp);
  67
  68static void tap_send(void *opaque);
  69static void tap_writable(void *opaque);
  70
  71static void tap_update_fd_handler(TAPState *s)
  72{
  73    qemu_set_fd_handler(s->fd,
  74                        s->read_poll && s->enabled ? tap_send : NULL,
  75                        s->write_poll && s->enabled ? tap_writable : NULL,
  76                        s);
  77}
  78
  79static void tap_read_poll(TAPState *s, bool enable)
  80{
  81    s->read_poll = enable;
  82    tap_update_fd_handler(s);
  83}
  84
  85static void tap_write_poll(TAPState *s, bool enable)
  86{
  87    s->write_poll = enable;
  88    tap_update_fd_handler(s);
  89}
  90
  91static void tap_writable(void *opaque)
  92{
  93    TAPState *s = opaque;
  94
  95    tap_write_poll(s, false);
  96
  97    qemu_flush_queued_packets(&s->nc);
  98}
  99
 100static ssize_t tap_write_packet(TAPState *s, const struct iovec *iov, int iovcnt)
 101{
 102    ssize_t len;
 103
 104    do {
 105        len = writev(s->fd, iov, iovcnt);
 106    } while (len == -1 && errno == EINTR);
 107
 108    if (len == -1 && errno == EAGAIN) {
 109        tap_write_poll(s, true);
 110        return 0;
 111    }
 112
 113    return len;
 114}
 115
 116static ssize_t tap_receive_iov(NetClientState *nc, const struct iovec *iov,
 117                               int iovcnt)
 118{
 119    TAPState *s = DO_UPCAST(TAPState, nc, nc);
 120    const struct iovec *iovp = iov;
 121    struct iovec iov_copy[iovcnt + 1];
 122    struct virtio_net_hdr_mrg_rxbuf hdr = { };
 123
 124    if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
 125        iov_copy[0].iov_base = &hdr;
 126        iov_copy[0].iov_len =  s->host_vnet_hdr_len;
 127        memcpy(&iov_copy[1], iov, iovcnt * sizeof(*iov));
 128        iovp = iov_copy;
 129        iovcnt++;
 130    }
 131
 132    return tap_write_packet(s, iovp, iovcnt);
 133}
 134
 135static ssize_t tap_receive_raw(NetClientState *nc, const uint8_t *buf, size_t size)
 136{
 137    TAPState *s = DO_UPCAST(TAPState, nc, nc);
 138    struct iovec iov[2];
 139    int iovcnt = 0;
 140    struct virtio_net_hdr_mrg_rxbuf hdr = { };
 141
 142    if (s->host_vnet_hdr_len) {
 143        iov[iovcnt].iov_base = &hdr;
 144        iov[iovcnt].iov_len  = s->host_vnet_hdr_len;
 145        iovcnt++;
 146    }
 147
 148    iov[iovcnt].iov_base = (char *)buf;
 149    iov[iovcnt].iov_len  = size;
 150    iovcnt++;
 151
 152    return tap_write_packet(s, iov, iovcnt);
 153}
 154
 155static ssize_t tap_receive(NetClientState *nc, const uint8_t *buf, size_t size)
 156{
 157    TAPState *s = DO_UPCAST(TAPState, nc, nc);
 158    struct iovec iov[1];
 159
 160    if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
 161        return tap_receive_raw(nc, buf, size);
 162    }
 163
 164    iov[0].iov_base = (char *)buf;
 165    iov[0].iov_len  = size;
 166
 167    return tap_write_packet(s, iov, 1);
 168}
 169
 170#ifndef __sun__
 171ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen)
 172{
 173    return read(tapfd, buf, maxlen);
 174}
 175#endif
 176
 177static void tap_send_completed(NetClientState *nc, ssize_t len)
 178{
 179    TAPState *s = DO_UPCAST(TAPState, nc, nc);
 180    tap_read_poll(s, true);
 181}
 182
 183static void tap_send(void *opaque)
 184{
 185    TAPState *s = opaque;
 186    int size;
 187    int packets = 0;
 188
 189    while (true) {
 190        uint8_t *buf = s->buf;
 191
 192        size = tap_read_packet(s->fd, s->buf, sizeof(s->buf));
 193        if (size <= 0) {
 194            break;
 195        }
 196
 197        if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
 198            buf  += s->host_vnet_hdr_len;
 199            size -= s->host_vnet_hdr_len;
 200        }
 201
 202        size = qemu_send_packet_async(&s->nc, buf, size, tap_send_completed);
 203        if (size == 0) {
 204            tap_read_poll(s, false);
 205            break;
 206        } else if (size < 0) {
 207            break;
 208        }
 209
 210        /*
 211         * When the host keeps receiving more packets while tap_send() is
 212         * running we can hog the QEMU global mutex.  Limit the number of
 213         * packets that are processed per tap_send() callback to prevent
 214         * stalling the guest.
 215         */
 216        packets++;
 217        if (packets >= 50) {
 218            break;
 219        }
 220    }
 221}
 222
 223static bool tap_has_ufo(NetClientState *nc)
 224{
 225    TAPState *s = DO_UPCAST(TAPState, nc, nc);
 226
 227    assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 228
 229    return s->has_ufo;
 230}
 231
 232static bool tap_has_vnet_hdr(NetClientState *nc)
 233{
 234    TAPState *s = DO_UPCAST(TAPState, nc, nc);
 235
 236    assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 237
 238    return !!s->host_vnet_hdr_len;
 239}
 240
 241static bool tap_has_vnet_hdr_len(NetClientState *nc, int len)
 242{
 243    TAPState *s = DO_UPCAST(TAPState, nc, nc);
 244
 245    assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 246
 247    return !!tap_probe_vnet_hdr_len(s->fd, len);
 248}
 249
 250static void tap_set_vnet_hdr_len(NetClientState *nc, int len)
 251{
 252    TAPState *s = DO_UPCAST(TAPState, nc, nc);
 253
 254    assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 255    assert(len == sizeof(struct virtio_net_hdr_mrg_rxbuf) ||
 256           len == sizeof(struct virtio_net_hdr));
 257
 258    tap_fd_set_vnet_hdr_len(s->fd, len);
 259    s->host_vnet_hdr_len = len;
 260}
 261
 262static void tap_using_vnet_hdr(NetClientState *nc, bool using_vnet_hdr)
 263{
 264    TAPState *s = DO_UPCAST(TAPState, nc, nc);
 265
 266    assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 267    assert(!!s->host_vnet_hdr_len == using_vnet_hdr);
 268
 269    s->using_vnet_hdr = using_vnet_hdr;
 270}
 271
 272static int tap_set_vnet_le(NetClientState *nc, bool is_le)
 273{
 274    TAPState *s = DO_UPCAST(TAPState, nc, nc);
 275
 276    return tap_fd_set_vnet_le(s->fd, is_le);
 277}
 278
 279static int tap_set_vnet_be(NetClientState *nc, bool is_be)
 280{
 281    TAPState *s = DO_UPCAST(TAPState, nc, nc);
 282
 283    return tap_fd_set_vnet_be(s->fd, is_be);
 284}
 285
 286static void tap_set_offload(NetClientState *nc, int csum, int tso4,
 287                     int tso6, int ecn, int ufo)
 288{
 289    TAPState *s = DO_UPCAST(TAPState, nc, nc);
 290    if (s->fd < 0) {
 291        return;
 292    }
 293
 294    tap_fd_set_offload(s->fd, csum, tso4, tso6, ecn, ufo);
 295}
 296
 297static void tap_exit_notify(Notifier *notifier, void *data)
 298{
 299    TAPState *s = container_of(notifier, TAPState, exit);
 300    Error *err = NULL;
 301
 302    if (s->down_script[0]) {
 303        launch_script(s->down_script, s->down_script_arg, s->fd, &err);
 304        if (err) {
 305            error_report_err(err);
 306        }
 307    }
 308}
 309
 310static void tap_cleanup(NetClientState *nc)
 311{
 312    TAPState *s = DO_UPCAST(TAPState, nc, nc);
 313
 314    if (s->vhost_net) {
 315        vhost_net_cleanup(s->vhost_net);
 316        g_free(s->vhost_net);
 317        s->vhost_net = NULL;
 318    }
 319
 320    qemu_purge_queued_packets(nc);
 321
 322    tap_exit_notify(&s->exit, NULL);
 323    qemu_remove_exit_notifier(&s->exit);
 324
 325    tap_read_poll(s, false);
 326    tap_write_poll(s, false);
 327    close(s->fd);
 328    s->fd = -1;
 329}
 330
 331static void tap_poll(NetClientState *nc, bool enable)
 332{
 333    TAPState *s = DO_UPCAST(TAPState, nc, nc);
 334    tap_read_poll(s, enable);
 335    tap_write_poll(s, enable);
 336}
 337
 338int tap_get_fd(NetClientState *nc)
 339{
 340    TAPState *s = DO_UPCAST(TAPState, nc, nc);
 341    assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 342    return s->fd;
 343}
 344
 345/* fd support */
 346
 347static NetClientInfo net_tap_info = {
 348    .type = NET_CLIENT_DRIVER_TAP,
 349    .size = sizeof(TAPState),
 350    .receive = tap_receive,
 351    .receive_raw = tap_receive_raw,
 352    .receive_iov = tap_receive_iov,
 353    .poll = tap_poll,
 354    .cleanup = tap_cleanup,
 355    .has_ufo = tap_has_ufo,
 356    .has_vnet_hdr = tap_has_vnet_hdr,
 357    .has_vnet_hdr_len = tap_has_vnet_hdr_len,
 358    .using_vnet_hdr = tap_using_vnet_hdr,
 359    .set_offload = tap_set_offload,
 360    .set_vnet_hdr_len = tap_set_vnet_hdr_len,
 361    .set_vnet_le = tap_set_vnet_le,
 362    .set_vnet_be = tap_set_vnet_be,
 363};
 364
 365static TAPState *net_tap_fd_init(NetClientState *peer,
 366                                 const char *model,
 367                                 const char *name,
 368                                 int fd,
 369                                 int vnet_hdr)
 370{
 371    NetClientState *nc;
 372    TAPState *s;
 373
 374    nc = qemu_new_net_client(&net_tap_info, peer, model, name);
 375
 376    s = DO_UPCAST(TAPState, nc, nc);
 377
 378    s->fd = fd;
 379    s->host_vnet_hdr_len = vnet_hdr ? sizeof(struct virtio_net_hdr) : 0;
 380    s->using_vnet_hdr = false;
 381    s->has_ufo = tap_probe_has_ufo(s->fd);
 382    s->enabled = true;
 383    tap_set_offload(&s->nc, 0, 0, 0, 0, 0);
 384    /*
 385     * Make sure host header length is set correctly in tap:
 386     * it might have been modified by another instance of qemu.
 387     */
 388    if (tap_probe_vnet_hdr_len(s->fd, s->host_vnet_hdr_len)) {
 389        tap_fd_set_vnet_hdr_len(s->fd, s->host_vnet_hdr_len);
 390    }
 391    tap_read_poll(s, true);
 392    s->vhost_net = NULL;
 393
 394    s->exit.notify = tap_exit_notify;
 395    qemu_add_exit_notifier(&s->exit);
 396
 397    return s;
 398}
 399
 400static void launch_script(const char *setup_script, const char *ifname,
 401                          int fd, Error **errp)
 402{
 403    int pid, status;
 404    char *args[3];
 405    char **parg;
 406
 407    /* try to launch network script */
 408    pid = fork();
 409    if (pid < 0) {
 410        error_setg_errno(errp, errno, "could not launch network script %s",
 411                         setup_script);
 412        return;
 413    }
 414    if (pid == 0) {
 415        int open_max = sysconf(_SC_OPEN_MAX), i;
 416
 417        for (i = 3; i < open_max; i++) {
 418            if (i != fd) {
 419                close(i);
 420            }
 421        }
 422        parg = args;
 423        *parg++ = (char *)setup_script;
 424        *parg++ = (char *)ifname;
 425        *parg = NULL;
 426        execv(setup_script, args);
 427        _exit(1);
 428    } else {
 429        while (waitpid(pid, &status, 0) != pid) {
 430            /* loop */
 431        }
 432
 433        if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
 434            return;
 435        }
 436        error_setg(errp, "network script %s failed with status %d",
 437                   setup_script, status);
 438    }
 439}
 440
 441static int recv_fd(int c)
 442{
 443    int fd;
 444    uint8_t msgbuf[CMSG_SPACE(sizeof(fd))];
 445    struct msghdr msg = {
 446        .msg_control = msgbuf,
 447        .msg_controllen = sizeof(msgbuf),
 448    };
 449    struct cmsghdr *cmsg;
 450    struct iovec iov;
 451    uint8_t req[1];
 452    ssize_t len;
 453
 454    cmsg = CMSG_FIRSTHDR(&msg);
 455    cmsg->cmsg_level = SOL_SOCKET;
 456    cmsg->cmsg_type = SCM_RIGHTS;
 457    cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
 458    msg.msg_controllen = cmsg->cmsg_len;
 459
 460    iov.iov_base = req;
 461    iov.iov_len = sizeof(req);
 462
 463    msg.msg_iov = &iov;
 464    msg.msg_iovlen = 1;
 465
 466    len = recvmsg(c, &msg, 0);
 467    if (len > 0) {
 468        memcpy(&fd, CMSG_DATA(cmsg), sizeof(fd));
 469        return fd;
 470    }
 471
 472    return len;
 473}
 474
 475static int net_bridge_run_helper(const char *helper, const char *bridge,
 476                                 Error **errp)
 477{
 478    sigset_t oldmask, mask;
 479    int pid, status;
 480    char *args[5];
 481    char **parg;
 482    int sv[2];
 483
 484    sigemptyset(&mask);
 485    sigaddset(&mask, SIGCHLD);
 486    sigprocmask(SIG_BLOCK, &mask, &oldmask);
 487
 488    if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) == -1) {
 489        error_setg_errno(errp, errno, "socketpair() failed");
 490        return -1;
 491    }
 492
 493    /* try to launch bridge helper */
 494    pid = fork();
 495    if (pid < 0) {
 496        error_setg_errno(errp, errno, "Can't fork bridge helper");
 497        return -1;
 498    }
 499    if (pid == 0) {
 500        int open_max = sysconf(_SC_OPEN_MAX), i;
 501        char fd_buf[6+10];
 502        char br_buf[6+IFNAMSIZ] = {0};
 503        char helper_cmd[PATH_MAX + sizeof(fd_buf) + sizeof(br_buf) + 15];
 504
 505        for (i = 3; i < open_max; i++) {
 506            if (i != sv[1]) {
 507                close(i);
 508            }
 509        }
 510
 511        snprintf(fd_buf, sizeof(fd_buf), "%s%d", "--fd=", sv[1]);
 512
 513        if (strrchr(helper, ' ') || strrchr(helper, '\t')) {
 514            /* assume helper is a command */
 515
 516            if (strstr(helper, "--br=") == NULL) {
 517                snprintf(br_buf, sizeof(br_buf), "%s%s", "--br=", bridge);
 518            }
 519
 520            snprintf(helper_cmd, sizeof(helper_cmd), "%s %s %s %s",
 521                     helper, "--use-vnet", fd_buf, br_buf);
 522
 523            parg = args;
 524            *parg++ = (char *)"sh";
 525            *parg++ = (char *)"-c";
 526            *parg++ = helper_cmd;
 527            *parg++ = NULL;
 528
 529            execv("/bin/sh", args);
 530        } else {
 531            /* assume helper is just the executable path name */
 532
 533            snprintf(br_buf, sizeof(br_buf), "%s%s", "--br=", bridge);
 534
 535            parg = args;
 536            *parg++ = (char *)helper;
 537            *parg++ = (char *)"--use-vnet";
 538            *parg++ = fd_buf;
 539            *parg++ = br_buf;
 540            *parg++ = NULL;
 541
 542            execv(helper, args);
 543        }
 544        _exit(1);
 545
 546    } else {
 547        int fd;
 548        int saved_errno;
 549
 550        close(sv[1]);
 551
 552        do {
 553            fd = recv_fd(sv[0]);
 554        } while (fd == -1 && errno == EINTR);
 555        saved_errno = errno;
 556
 557        close(sv[0]);
 558
 559        while (waitpid(pid, &status, 0) != pid) {
 560            /* loop */
 561        }
 562        sigprocmask(SIG_SETMASK, &oldmask, NULL);
 563        if (fd < 0) {
 564            error_setg_errno(errp, saved_errno,
 565                             "failed to recv file descriptor");
 566            return -1;
 567        }
 568        if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 569            error_setg(errp, "bridge helper failed");
 570            return -1;
 571        }
 572        return fd;
 573    }
 574}
 575
 576int net_init_bridge(const Netdev *netdev, const char *name,
 577                    NetClientState *peer, Error **errp)
 578{
 579    const NetdevBridgeOptions *bridge;
 580    const char *helper, *br;
 581    TAPState *s;
 582    int fd, vnet_hdr;
 583
 584    assert(netdev->type == NET_CLIENT_DRIVER_BRIDGE);
 585    bridge = &netdev->u.bridge;
 586
 587    helper = bridge->has_helper ? bridge->helper : DEFAULT_BRIDGE_HELPER;
 588    br     = bridge->has_br     ? bridge->br     : DEFAULT_BRIDGE_INTERFACE;
 589
 590    fd = net_bridge_run_helper(helper, br, errp);
 591    if (fd == -1) {
 592        return -1;
 593    }
 594
 595    fcntl(fd, F_SETFL, O_NONBLOCK);
 596    vnet_hdr = tap_probe_vnet_hdr(fd);
 597    s = net_tap_fd_init(peer, "bridge", name, fd, vnet_hdr);
 598
 599    snprintf(s->nc.info_str, sizeof(s->nc.info_str), "helper=%s,br=%s", helper,
 600             br);
 601
 602    return 0;
 603}
 604
 605static int net_tap_init(const NetdevTapOptions *tap, int *vnet_hdr,
 606                        const char *setup_script, char *ifname,
 607                        size_t ifname_sz, int mq_required, Error **errp)
 608{
 609    Error *err = NULL;
 610    int fd, vnet_hdr_required;
 611
 612    if (tap->has_vnet_hdr) {
 613        *vnet_hdr = tap->vnet_hdr;
 614        vnet_hdr_required = *vnet_hdr;
 615    } else {
 616        *vnet_hdr = 1;
 617        vnet_hdr_required = 0;
 618    }
 619
 620    TFR(fd = tap_open(ifname, ifname_sz, vnet_hdr, vnet_hdr_required,
 621                      mq_required, errp));
 622    if (fd < 0) {
 623        return -1;
 624    }
 625
 626    if (setup_script &&
 627        setup_script[0] != '\0' &&
 628        strcmp(setup_script, "no") != 0) {
 629        launch_script(setup_script, ifname, fd, &err);
 630        if (err) {
 631            error_propagate(errp, err);
 632            close(fd);
 633            return -1;
 634        }
 635    }
 636
 637    return fd;
 638}
 639
 640#define MAX_TAP_QUEUES 1024
 641
 642static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
 643                             const char *model, const char *name,
 644                             const char *ifname, const char *script,
 645                             const char *downscript, const char *vhostfdname,
 646                             int vnet_hdr, int fd, Error **errp)
 647{
 648    Error *err = NULL;
 649    TAPState *s = net_tap_fd_init(peer, model, name, fd, vnet_hdr);
 650    int vhostfd;
 651
 652    tap_set_sndbuf(s->fd, tap, &err);
 653    if (err) {
 654        error_propagate(errp, err);
 655        return;
 656    }
 657
 658    if (tap->has_fd || tap->has_fds) {
 659        snprintf(s->nc.info_str, sizeof(s->nc.info_str), "fd=%d", fd);
 660    } else if (tap->has_helper) {
 661        snprintf(s->nc.info_str, sizeof(s->nc.info_str), "helper=%s",
 662                 tap->helper);
 663    } else {
 664        snprintf(s->nc.info_str, sizeof(s->nc.info_str),
 665                 "ifname=%s,script=%s,downscript=%s", ifname, script,
 666                 downscript);
 667
 668        if (strcmp(downscript, "no") != 0) {
 669            snprintf(s->down_script, sizeof(s->down_script), "%s", downscript);
 670            snprintf(s->down_script_arg, sizeof(s->down_script_arg),
 671                     "%s", ifname);
 672        }
 673    }
 674
 675    if (tap->has_vhost ? tap->vhost :
 676        vhostfdname || (tap->has_vhostforce && tap->vhostforce)) {
 677        VhostNetOptions options;
 678
 679        options.backend_type = VHOST_BACKEND_TYPE_KERNEL;
 680        options.net_backend = &s->nc;
 681        if (tap->has_poll_us) {
 682            options.busyloop_timeout = tap->poll_us;
 683        } else {
 684            options.busyloop_timeout = 0;
 685        }
 686
 687        if (vhostfdname) {
 688            vhostfd = monitor_fd_param(cur_mon, vhostfdname, &err);
 689            if (vhostfd == -1) {
 690                if (tap->has_vhostforce && tap->vhostforce) {
 691                    error_propagate(errp, err);
 692                } else {
 693                    warn_report_err(err);
 694                }
 695                return;
 696            }
 697            qemu_set_nonblock(vhostfd);
 698        } else {
 699            vhostfd = open("/dev/vhost-net", O_RDWR);
 700            if (vhostfd < 0) {
 701                if (tap->has_vhostforce && tap->vhostforce) {
 702                    error_setg_errno(errp, errno,
 703                                     "tap: open vhost char device failed");
 704                } else {
 705                    warn_report("tap: open vhost char device failed: %s",
 706                                strerror(errno));
 707                }
 708                return;
 709            }
 710            fcntl(vhostfd, F_SETFL, O_NONBLOCK);
 711        }
 712        options.opaque = (void *)(uintptr_t)vhostfd;
 713
 714        s->vhost_net = vhost_net_init(&options);
 715        if (!s->vhost_net) {
 716            if (tap->has_vhostforce && tap->vhostforce) {
 717                error_setg(errp, VHOST_NET_INIT_FAILED);
 718            } else {
 719                warn_report(VHOST_NET_INIT_FAILED);
 720            }
 721            return;
 722        }
 723    } else if (vhostfdname) {
 724        error_setg(errp, "vhostfd(s)= is not valid without vhost");
 725    }
 726}
 727
 728static int get_fds(char *str, char *fds[], int max)
 729{
 730    char *ptr = str, *this;
 731    size_t len = strlen(str);
 732    int i = 0;
 733
 734    while (i < max && ptr < str + len) {
 735        this = strchr(ptr, ':');
 736
 737        if (this == NULL) {
 738            fds[i] = g_strdup(ptr);
 739        } else {
 740            fds[i] = g_strndup(ptr, this - ptr);
 741        }
 742
 743        i++;
 744        if (this == NULL) {
 745            break;
 746        } else {
 747            ptr = this + 1;
 748        }
 749    }
 750
 751    return i;
 752}
 753
 754int net_init_tap(const Netdev *netdev, const char *name,
 755                 NetClientState *peer, Error **errp)
 756{
 757    const NetdevTapOptions *tap;
 758    int fd, vnet_hdr = 0, i = 0, queues;
 759    /* for the no-fd, no-helper case */
 760    const char *script = NULL; /* suppress wrong "uninit'd use" gcc warning */
 761    const char *downscript = NULL;
 762    Error *err = NULL;
 763    const char *vhostfdname;
 764    char ifname[128];
 765
 766    assert(netdev->type == NET_CLIENT_DRIVER_TAP);
 767    tap = &netdev->u.tap;
 768    queues = tap->has_queues ? tap->queues : 1;
 769    vhostfdname = tap->has_vhostfd ? tap->vhostfd : NULL;
 770
 771    /* QEMU hubs do not support multiqueue tap, in this case peer is set.
 772     * For -netdev, peer is always NULL. */
 773    if (peer && (tap->has_queues || tap->has_fds || tap->has_vhostfds)) {
 774        error_setg(errp, "Multiqueue tap cannot be used with hubs");
 775        return -1;
 776    }
 777
 778    if (tap->has_fd) {
 779        if (tap->has_ifname || tap->has_script || tap->has_downscript ||
 780            tap->has_vnet_hdr || tap->has_helper || tap->has_queues ||
 781            tap->has_fds || tap->has_vhostfds) {
 782            error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
 783                       "helper=, queues=, fds=, and vhostfds= "
 784                       "are invalid with fd=");
 785            return -1;
 786        }
 787
 788        fd = monitor_fd_param(cur_mon, tap->fd, &err);
 789        if (fd == -1) {
 790            error_propagate(errp, err);
 791            return -1;
 792        }
 793
 794        fcntl(fd, F_SETFL, O_NONBLOCK);
 795
 796        vnet_hdr = tap_probe_vnet_hdr(fd);
 797
 798        net_init_tap_one(tap, peer, "tap", name, NULL,
 799                         script, downscript,
 800                         vhostfdname, vnet_hdr, fd, &err);
 801        if (err) {
 802            error_propagate(errp, err);
 803            return -1;
 804        }
 805    } else if (tap->has_fds) {
 806        char **fds;
 807        char **vhost_fds;
 808        int nfds = 0, nvhosts = 0;
 809        int ret = 0;
 810
 811        if (tap->has_ifname || tap->has_script || tap->has_downscript ||
 812            tap->has_vnet_hdr || tap->has_helper || tap->has_queues ||
 813            tap->has_vhostfd) {
 814            error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
 815                       "helper=, queues=, and vhostfd= "
 816                       "are invalid with fds=");
 817            return -1;
 818        }
 819
 820        fds = g_new0(char *, MAX_TAP_QUEUES);
 821        vhost_fds = g_new0(char *, MAX_TAP_QUEUES);
 822
 823        nfds = get_fds(tap->fds, fds, MAX_TAP_QUEUES);
 824        if (tap->has_vhostfds) {
 825            nvhosts = get_fds(tap->vhostfds, vhost_fds, MAX_TAP_QUEUES);
 826            if (nfds != nvhosts) {
 827                error_setg(errp, "The number of fds passed does not match "
 828                           "the number of vhostfds passed");
 829                ret = -1;
 830                goto free_fail;
 831            }
 832        }
 833
 834        for (i = 0; i < nfds; i++) {
 835            fd = monitor_fd_param(cur_mon, fds[i], &err);
 836            if (fd == -1) {
 837                error_propagate(errp, err);
 838                ret = -1;
 839                goto free_fail;
 840            }
 841
 842            fcntl(fd, F_SETFL, O_NONBLOCK);
 843
 844            if (i == 0) {
 845                vnet_hdr = tap_probe_vnet_hdr(fd);
 846            } else if (vnet_hdr != tap_probe_vnet_hdr(fd)) {
 847                error_setg(errp,
 848                           "vnet_hdr not consistent across given tap fds");
 849                ret = -1;
 850                goto free_fail;
 851            }
 852
 853            net_init_tap_one(tap, peer, "tap", name, ifname,
 854                             script, downscript,
 855                             tap->has_vhostfds ? vhost_fds[i] : NULL,
 856                             vnet_hdr, fd, &err);
 857            if (err) {
 858                error_propagate(errp, err);
 859                ret = -1;
 860                goto free_fail;
 861            }
 862        }
 863
 864free_fail:
 865        for (i = 0; i < nvhosts; i++) {
 866            g_free(vhost_fds[i]);
 867        }
 868        for (i = 0; i < nfds; i++) {
 869            g_free(fds[i]);
 870        }
 871        g_free(fds);
 872        g_free(vhost_fds);
 873        return ret;
 874    } else if (tap->has_helper) {
 875        if (tap->has_ifname || tap->has_script || tap->has_downscript ||
 876            tap->has_vnet_hdr || tap->has_queues || tap->has_vhostfds) {
 877            error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
 878                       "queues=, and vhostfds= are invalid with helper=");
 879            return -1;
 880        }
 881
 882        fd = net_bridge_run_helper(tap->helper,
 883                                   tap->has_br ?
 884                                   tap->br : DEFAULT_BRIDGE_INTERFACE,
 885                                   errp);
 886        if (fd == -1) {
 887            return -1;
 888        }
 889
 890        fcntl(fd, F_SETFL, O_NONBLOCK);
 891        vnet_hdr = tap_probe_vnet_hdr(fd);
 892
 893        net_init_tap_one(tap, peer, "bridge", name, ifname,
 894                         script, downscript, vhostfdname,
 895                         vnet_hdr, fd, &err);
 896        if (err) {
 897            error_propagate(errp, err);
 898            close(fd);
 899            return -1;
 900        }
 901    } else {
 902        if (tap->has_vhostfds) {
 903            error_setg(errp, "vhostfds= is invalid if fds= wasn't specified");
 904            return -1;
 905        }
 906        script = tap->has_script ? tap->script : DEFAULT_NETWORK_SCRIPT;
 907        downscript = tap->has_downscript ? tap->downscript :
 908            DEFAULT_NETWORK_DOWN_SCRIPT;
 909
 910        if (tap->has_ifname) {
 911            pstrcpy(ifname, sizeof ifname, tap->ifname);
 912        } else {
 913            ifname[0] = '\0';
 914        }
 915
 916        for (i = 0; i < queues; i++) {
 917            fd = net_tap_init(tap, &vnet_hdr, i >= 1 ? "no" : script,
 918                              ifname, sizeof ifname, queues > 1, errp);
 919            if (fd == -1) {
 920                return -1;
 921            }
 922
 923            if (queues > 1 && i == 0 && !tap->has_ifname) {
 924                if (tap_fd_get_ifname(fd, ifname)) {
 925                    error_setg(errp, "Fail to get ifname");
 926                    close(fd);
 927                    return -1;
 928                }
 929            }
 930
 931            net_init_tap_one(tap, peer, "tap", name, ifname,
 932                             i >= 1 ? "no" : script,
 933                             i >= 1 ? "no" : downscript,
 934                             vhostfdname, vnet_hdr, fd, &err);
 935            if (err) {
 936                error_propagate(errp, err);
 937                close(fd);
 938                return -1;
 939            }
 940        }
 941    }
 942
 943    return 0;
 944}
 945
 946VHostNetState *tap_get_vhost_net(NetClientState *nc)
 947{
 948    TAPState *s = DO_UPCAST(TAPState, nc, nc);
 949    assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
 950    return s->vhost_net;
 951}
 952
 953int tap_enable(NetClientState *nc)
 954{
 955    TAPState *s = DO_UPCAST(TAPState, nc, nc);
 956    int ret;
 957
 958    if (s->enabled) {
 959        return 0;
 960    } else {
 961        ret = tap_fd_enable(s->fd);
 962        if (ret == 0) {
 963            s->enabled = true;
 964            tap_update_fd_handler(s);
 965        }
 966        return ret;
 967    }
 968}
 969
 970int tap_disable(NetClientState *nc)
 971{
 972    TAPState *s = DO_UPCAST(TAPState, nc, nc);
 973    int ret;
 974
 975    if (s->enabled == 0) {
 976        return 0;
 977    } else {
 978        ret = tap_fd_disable(s->fd);
 979        if (ret == 0) {
 980            qemu_purge_queued_packets(nc);
 981            s->enabled = false;
 982            tap_update_fd_handler(s);
 983        }
 984        return ret;
 985    }
 986}
 987