qemu/net/tap.c
Daniel P. Berrange e7b347d0bf net: detect errors from probing vnet hdr flag for TAP devices
When QEMU sets up a tap based network device backend, it mostly ignores errors
reported from various ioctl() calls it makes, assuming the TAP file descriptor
is valid. This assumption can easily be violated when the user is passing in a
pre-opened file descriptor. At best, the ioctls may fail with a -EBADF, but if
the user passes in a bogus FD number that happens to clash with a FD number that
QEMU has opened internally for another reason, a wide variety of errnos may
result, as the TUNGETIFF ioctl number may map to a completely different command
on a different type of file.

By ignoring all these errors, QEMU sets up a zombie network backend that will
never pass any data. Even worse, when QEMU shuts down, or that network backend
is hot-removed, it will close this bogus file descriptor, which could belong to
another QEMU device backend.

There's no obvious guaranteed reliable way to detect that a FD genuinely is a
TAP device, as opposed to a UNIX socket, or pipe, or something else. Checking
the errno from probing vnet hdr flag though, does catch the big common cases.
ie calling TUNGETIFF will return EBADF for an invalid FD, and ENOTTY when FD is
a UNIX socket, or pipe which catches accidental collisions with FDs used for
stdio, or monitor socket.

Previously the example below where bogus fd 9 collides with the FD used for the
chardev saw:

$ ./x86_64-softmmu/qemu-system-x86_64 -netdev tap,id=hostnet0,fd=9 \
  -chardev socket,id=charchannel0,path=/tmp/qga,server,nowait \
  -monitor stdio -vnc :0
qemu-system-x86_64: -netdev tap,id=hostnet0,fd=9: TUNGETIFF ioctl() failed: Inappropriate ioctl for device
TUNSETOFFLOAD ioctl() failed: Bad address
QEMU 2.9.1 monitor - type 'help' for more information
(qemu) Warning: netdev hostnet0 has no peer

which gives a running QEMU with a zombie network backend.

With this change applied we get an error message and QEMU immediately exits
before carrying on and making a bigger disaster:

$ ./x86_64-softmmu/qemu-system-x86_64 -netdev tap,id=hostnet0,fd=9 \
  -chardev socket,id=charchannel0,path=/tmp/qga,server,nowait \
  -monitor stdio -vnc :0
qemu-system-x86_64: -netdev tap,id=hostnet0,vhost=on,fd=9: Unable to query TUNGETIFF on FD 9: Inappropriate ioctl for device

Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Tested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-id: 20171027085548.3472-1-berrange@redhat.com
[lv: to simplify, don't check on EINVAL with TUNGETIFF as it exists since v2.6.27]
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
2020-07-15 21:00:13 +08:00

1022 lines
28 KiB
C

/*
* QEMU System Emulator
*
* Copyright (c) 2003-2008 Fabrice Bellard
* Copyright (c) 2009 Red Hat, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "tap_int.h"
#include <sys/ioctl.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <net/if.h>
#include "net/net.h"
#include "clients.h"
#include "monitor/monitor.h"
#include "sysemu/sysemu.h"
#include "qapi/error.h"
#include "qemu-common.h"
#include "qemu/cutils.h"
#include "qemu/error-report.h"
#include "qemu/main-loop.h"
#include "qemu/sockets.h"
#include "net/tap.h"
#include "net/vhost_net.h"
typedef struct TAPState {
NetClientState nc;
int fd;
char down_script[1024];
char down_script_arg[128];
uint8_t buf[NET_BUFSIZE];
bool read_poll;
bool write_poll;
bool using_vnet_hdr;
bool has_ufo;
bool enabled;
VHostNetState *vhost_net;
unsigned host_vnet_hdr_len;
Notifier exit;
} TAPState;
static void launch_script(const char *setup_script, const char *ifname,
int fd, Error **errp);
static void tap_send(void *opaque);
static void tap_writable(void *opaque);
static void tap_update_fd_handler(TAPState *s)
{
qemu_set_fd_handler(s->fd,
s->read_poll && s->enabled ? tap_send : NULL,
s->write_poll && s->enabled ? tap_writable : NULL,
s);
}
static void tap_read_poll(TAPState *s, bool enable)
{
s->read_poll = enable;
tap_update_fd_handler(s);
}
static void tap_write_poll(TAPState *s, bool enable)
{
s->write_poll = enable;
tap_update_fd_handler(s);
}
static void tap_writable(void *opaque)
{
TAPState *s = opaque;
tap_write_poll(s, false);
qemu_flush_queued_packets(&s->nc);
}
static ssize_t tap_write_packet(TAPState *s, const struct iovec *iov, int iovcnt)
{
ssize_t len;
do {
len = writev(s->fd, iov, iovcnt);
} while (len == -1 && errno == EINTR);
if (len == -1 && errno == EAGAIN) {
tap_write_poll(s, true);
return 0;
}
return len;
}
static ssize_t tap_receive_iov(NetClientState *nc, const struct iovec *iov,
int iovcnt)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
const struct iovec *iovp = iov;
struct iovec iov_copy[iovcnt + 1];
struct virtio_net_hdr_mrg_rxbuf hdr = { };
if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
iov_copy[0].iov_base = &hdr;
iov_copy[0].iov_len = s->host_vnet_hdr_len;
memcpy(&iov_copy[1], iov, iovcnt * sizeof(*iov));
iovp = iov_copy;
iovcnt++;
}
return tap_write_packet(s, iovp, iovcnt);
}
static ssize_t tap_receive_raw(NetClientState *nc, const uint8_t *buf, size_t size)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
struct iovec iov[2];
int iovcnt = 0;
struct virtio_net_hdr_mrg_rxbuf hdr = { };
if (s->host_vnet_hdr_len) {
iov[iovcnt].iov_base = &hdr;
iov[iovcnt].iov_len = s->host_vnet_hdr_len;
iovcnt++;
}
iov[iovcnt].iov_base = (char *)buf;
iov[iovcnt].iov_len = size;
iovcnt++;
return tap_write_packet(s, iov, iovcnt);
}
static ssize_t tap_receive(NetClientState *nc, const uint8_t *buf, size_t size)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
struct iovec iov[1];
if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
return tap_receive_raw(nc, buf, size);
}
iov[0].iov_base = (char *)buf;
iov[0].iov_len = size;
return tap_write_packet(s, iov, 1);
}
#ifndef __sun__
ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen)
{
return read(tapfd, buf, maxlen);
}
#endif
static void tap_send_completed(NetClientState *nc, ssize_t len)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
tap_read_poll(s, true);
}
static void tap_send(void *opaque)
{
TAPState *s = opaque;
int size;
int packets = 0;
while (true) {
uint8_t *buf = s->buf;
size = tap_read_packet(s->fd, s->buf, sizeof(s->buf));
if (size <= 0) {
break;
}
if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
buf += s->host_vnet_hdr_len;
size -= s->host_vnet_hdr_len;
}
size = qemu_send_packet_async(&s->nc, buf, size, tap_send_completed);
if (size == 0) {
tap_read_poll(s, false);
break;
} else if (size < 0) {
break;
}
/*
* When the host keeps receiving more packets while tap_send() is
* running we can hog the QEMU global mutex. Limit the number of
* packets that are processed per tap_send() callback to prevent
* stalling the guest.
*/
packets++;
if (packets >= 50) {
break;
}
}
}
static bool tap_has_ufo(NetClientState *nc)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
return s->has_ufo;
}
static bool tap_has_vnet_hdr(NetClientState *nc)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
return !!s->host_vnet_hdr_len;
}
static bool tap_has_vnet_hdr_len(NetClientState *nc, int len)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
return !!tap_probe_vnet_hdr_len(s->fd, len);
}
static void tap_set_vnet_hdr_len(NetClientState *nc, int len)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
assert(len == sizeof(struct virtio_net_hdr_mrg_rxbuf) ||
len == sizeof(struct virtio_net_hdr) ||
len == sizeof(struct virtio_net_hdr_v1_hash));
tap_fd_set_vnet_hdr_len(s->fd, len);
s->host_vnet_hdr_len = len;
}
static void tap_using_vnet_hdr(NetClientState *nc, bool using_vnet_hdr)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
assert(!!s->host_vnet_hdr_len == using_vnet_hdr);
s->using_vnet_hdr = using_vnet_hdr;
}
static int tap_set_vnet_le(NetClientState *nc, bool is_le)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
return tap_fd_set_vnet_le(s->fd, is_le);
}
static int tap_set_vnet_be(NetClientState *nc, bool is_be)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
return tap_fd_set_vnet_be(s->fd, is_be);
}
static void tap_set_offload(NetClientState *nc, int csum, int tso4,
int tso6, int ecn, int ufo)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
if (s->fd < 0) {
return;
}
tap_fd_set_offload(s->fd, csum, tso4, tso6, ecn, ufo);
}
static void tap_exit_notify(Notifier *notifier, void *data)
{
TAPState *s = container_of(notifier, TAPState, exit);
Error *err = NULL;
if (s->down_script[0]) {
launch_script(s->down_script, s->down_script_arg, s->fd, &err);
if (err) {
error_report_err(err);
}
}
}
static void tap_cleanup(NetClientState *nc)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
if (s->vhost_net) {
vhost_net_cleanup(s->vhost_net);
g_free(s->vhost_net);
s->vhost_net = NULL;
}
qemu_purge_queued_packets(nc);
tap_exit_notify(&s->exit, NULL);
qemu_remove_exit_notifier(&s->exit);
tap_read_poll(s, false);
tap_write_poll(s, false);
close(s->fd);
s->fd = -1;
}
static void tap_poll(NetClientState *nc, bool enable)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
tap_read_poll(s, enable);
tap_write_poll(s, enable);
}
int tap_get_fd(NetClientState *nc)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
return s->fd;
}
/* fd support */
static NetClientInfo net_tap_info = {
.type = NET_CLIENT_DRIVER_TAP,
.size = sizeof(TAPState),
.receive = tap_receive,
.receive_raw = tap_receive_raw,
.receive_iov = tap_receive_iov,
.poll = tap_poll,
.cleanup = tap_cleanup,
.has_ufo = tap_has_ufo,
.has_vnet_hdr = tap_has_vnet_hdr,
.has_vnet_hdr_len = tap_has_vnet_hdr_len,
.using_vnet_hdr = tap_using_vnet_hdr,
.set_offload = tap_set_offload,
.set_vnet_hdr_len = tap_set_vnet_hdr_len,
.set_vnet_le = tap_set_vnet_le,
.set_vnet_be = tap_set_vnet_be,
};
static TAPState *net_tap_fd_init(NetClientState *peer,
const char *model,
const char *name,
int fd,
int vnet_hdr)
{
NetClientState *nc;
TAPState *s;
nc = qemu_new_net_client(&net_tap_info, peer, model, name);
s = DO_UPCAST(TAPState, nc, nc);
s->fd = fd;
s->host_vnet_hdr_len = vnet_hdr ? sizeof(struct virtio_net_hdr) : 0;
s->using_vnet_hdr = false;
s->has_ufo = tap_probe_has_ufo(s->fd);
s->enabled = true;
tap_set_offload(&s->nc, 0, 0, 0, 0, 0);
/*
* Make sure host header length is set correctly in tap:
* it might have been modified by another instance of qemu.
*/
if (tap_probe_vnet_hdr_len(s->fd, s->host_vnet_hdr_len)) {
tap_fd_set_vnet_hdr_len(s->fd, s->host_vnet_hdr_len);
}
tap_read_poll(s, true);
s->vhost_net = NULL;
s->exit.notify = tap_exit_notify;
qemu_add_exit_notifier(&s->exit);
return s;
}
static void launch_script(const char *setup_script, const char *ifname,
int fd, Error **errp)
{
int pid, status;
char *args[3];
char **parg;
/* try to launch network script */
pid = fork();
if (pid < 0) {
error_setg_errno(errp, errno, "could not launch network script %s",
setup_script);
return;
}
if (pid == 0) {
int open_max = sysconf(_SC_OPEN_MAX), i;
for (i = 3; i < open_max; i++) {
if (i != fd) {
close(i);
}
}
parg = args;
*parg++ = (char *)setup_script;
*parg++ = (char *)ifname;
*parg = NULL;
execv(setup_script, args);
_exit(1);
} else {
while (waitpid(pid, &status, 0) != pid) {
/* loop */
}
if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
return;
}
error_setg(errp, "network script %s failed with status %d",
setup_script, status);
}
}
static int recv_fd(int c)
{
int fd;
uint8_t msgbuf[CMSG_SPACE(sizeof(fd))];
struct msghdr msg = {
.msg_control = msgbuf,
.msg_controllen = sizeof(msgbuf),
};
struct cmsghdr *cmsg;
struct iovec iov;
uint8_t req[1];
ssize_t len;
cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
msg.msg_controllen = cmsg->cmsg_len;
iov.iov_base = req;
iov.iov_len = sizeof(req);
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
len = recvmsg(c, &msg, 0);
if (len > 0) {
memcpy(&fd, CMSG_DATA(cmsg), sizeof(fd));
return fd;
}
return len;
}
static int net_bridge_run_helper(const char *helper, const char *bridge,
Error **errp)
{
sigset_t oldmask, mask;
int pid, status;
char *args[5];
char **parg;
int sv[2];
sigemptyset(&mask);
sigaddset(&mask, SIGCHLD);
sigprocmask(SIG_BLOCK, &mask, &oldmask);
if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) == -1) {
error_setg_errno(errp, errno, "socketpair() failed");
return -1;
}
/* try to launch bridge helper */
pid = fork();
if (pid < 0) {
error_setg_errno(errp, errno, "Can't fork bridge helper");
return -1;
}
if (pid == 0) {
int open_max = sysconf(_SC_OPEN_MAX), i;
char *fd_buf = NULL;
char *br_buf = NULL;
char *helper_cmd = NULL;
for (i = 3; i < open_max; i++) {
if (i != sv[1]) {
close(i);
}
}
fd_buf = g_strdup_printf("%s%d", "--fd=", sv[1]);
if (strrchr(helper, ' ') || strrchr(helper, '\t')) {
/* assume helper is a command */
if (strstr(helper, "--br=") == NULL) {
br_buf = g_strdup_printf("%s%s", "--br=", bridge);
}
helper_cmd = g_strdup_printf("%s %s %s %s", helper,
"--use-vnet", fd_buf, br_buf ? br_buf : "");
parg = args;
*parg++ = (char *)"sh";
*parg++ = (char *)"-c";
*parg++ = helper_cmd;
*parg++ = NULL;
execv("/bin/sh", args);
g_free(helper_cmd);
} else {
/* assume helper is just the executable path name */
br_buf = g_strdup_printf("%s%s", "--br=", bridge);
parg = args;
*parg++ = (char *)helper;
*parg++ = (char *)"--use-vnet";
*parg++ = fd_buf;
*parg++ = br_buf;
*parg++ = NULL;
execv(helper, args);
}
g_free(fd_buf);
g_free(br_buf);
_exit(1);
} else {
int fd;
int saved_errno;
close(sv[1]);
do {
fd = recv_fd(sv[0]);
} while (fd == -1 && errno == EINTR);
saved_errno = errno;
close(sv[0]);
while (waitpid(pid, &status, 0) != pid) {
/* loop */
}
sigprocmask(SIG_SETMASK, &oldmask, NULL);
if (fd < 0) {
error_setg_errno(errp, saved_errno,
"failed to recv file descriptor");
return -1;
}
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
error_setg(errp, "bridge helper failed");
return -1;
}
return fd;
}
}
int net_init_bridge(const Netdev *netdev, const char *name,
NetClientState *peer, Error **errp)
{
const NetdevBridgeOptions *bridge;
const char *helper, *br;
TAPState *s;
int fd, vnet_hdr;
assert(netdev->type == NET_CLIENT_DRIVER_BRIDGE);
bridge = &netdev->u.bridge;
helper = bridge->has_helper ? bridge->helper : DEFAULT_BRIDGE_HELPER;
br = bridge->has_br ? bridge->br : DEFAULT_BRIDGE_INTERFACE;
fd = net_bridge_run_helper(helper, br, errp);
if (fd == -1) {
return -1;
}
qemu_set_nonblock(fd);
vnet_hdr = tap_probe_vnet_hdr(fd, errp);
if (vnet_hdr < 0) {
close(fd);
return -1;
}
s = net_tap_fd_init(peer, "bridge", name, fd, vnet_hdr);
snprintf(s->nc.info_str, sizeof(s->nc.info_str), "helper=%s,br=%s", helper,
br);
return 0;
}
static int net_tap_init(const NetdevTapOptions *tap, int *vnet_hdr,
const char *setup_script, char *ifname,
size_t ifname_sz, int mq_required, Error **errp)
{
Error *err = NULL;
int fd, vnet_hdr_required;
if (tap->has_vnet_hdr) {
*vnet_hdr = tap->vnet_hdr;
vnet_hdr_required = *vnet_hdr;
} else {
*vnet_hdr = 1;
vnet_hdr_required = 0;
}
TFR(fd = tap_open(ifname, ifname_sz, vnet_hdr, vnet_hdr_required,
mq_required, errp));
if (fd < 0) {
return -1;
}
if (setup_script &&
setup_script[0] != '\0' &&
strcmp(setup_script, "no") != 0) {
launch_script(setup_script, ifname, fd, &err);
if (err) {
error_propagate(errp, err);
close(fd);
return -1;
}
}
return fd;
}
#define MAX_TAP_QUEUES 1024
static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
const char *model, const char *name,
const char *ifname, const char *script,
const char *downscript, const char *vhostfdname,
int vnet_hdr, int fd, Error **errp)
{
Error *err = NULL;
TAPState *s = net_tap_fd_init(peer, model, name, fd, vnet_hdr);
int vhostfd;
tap_set_sndbuf(s->fd, tap, &err);
if (err) {
error_propagate(errp, err);
return;
}
if (tap->has_fd || tap->has_fds) {
snprintf(s->nc.info_str, sizeof(s->nc.info_str), "fd=%d", fd);
} else if (tap->has_helper) {
snprintf(s->nc.info_str, sizeof(s->nc.info_str), "helper=%s",
tap->helper);
} else {
snprintf(s->nc.info_str, sizeof(s->nc.info_str),
"ifname=%s,script=%s,downscript=%s", ifname, script,
downscript);
if (strcmp(downscript, "no") != 0) {
snprintf(s->down_script, sizeof(s->down_script), "%s", downscript);
snprintf(s->down_script_arg, sizeof(s->down_script_arg),
"%s", ifname);
}
}
if (tap->has_vhost ? tap->vhost :
vhostfdname || (tap->has_vhostforce && tap->vhostforce)) {
VhostNetOptions options;
options.backend_type = VHOST_BACKEND_TYPE_KERNEL;
options.net_backend = &s->nc;
if (tap->has_poll_us) {
options.busyloop_timeout = tap->poll_us;
} else {
options.busyloop_timeout = 0;
}
if (vhostfdname) {
int ret;
vhostfd = monitor_fd_param(cur_mon, vhostfdname, &err);
if (vhostfd == -1) {
if (tap->has_vhostforce && tap->vhostforce) {
error_propagate(errp, err);
} else {
warn_report_err(err);
}
return;
}
ret = qemu_try_set_nonblock(vhostfd);
if (ret < 0) {
error_setg_errno(errp, -ret, "%s: Can't use file descriptor %d",
name, fd);
return;
}
} else {
vhostfd = open("/dev/vhost-net", O_RDWR);
if (vhostfd < 0) {
if (tap->has_vhostforce && tap->vhostforce) {
error_setg_errno(errp, errno,
"tap: open vhost char device failed");
} else {
warn_report("tap: open vhost char device failed: %s",
strerror(errno));
}
return;
}
qemu_set_nonblock(vhostfd);
}
options.opaque = (void *)(uintptr_t)vhostfd;
s->vhost_net = vhost_net_init(&options);
if (!s->vhost_net) {
if (tap->has_vhostforce && tap->vhostforce) {
error_setg(errp, VHOST_NET_INIT_FAILED);
} else {
warn_report(VHOST_NET_INIT_FAILED);
}
return;
}
} else if (vhostfdname) {
error_setg(errp, "vhostfd(s)= is not valid without vhost");
}
}
static int get_fds(char *str, char *fds[], int max)
{
char *ptr = str, *this;
size_t len = strlen(str);
int i = 0;
while (i < max && ptr < str + len) {
this = strchr(ptr, ':');
if (this == NULL) {
fds[i] = g_strdup(ptr);
} else {
fds[i] = g_strndup(ptr, this - ptr);
}
i++;
if (this == NULL) {
break;
} else {
ptr = this + 1;
}
}
return i;
}
int net_init_tap(const Netdev *netdev, const char *name,
NetClientState *peer, Error **errp)
{
const NetdevTapOptions *tap;
int fd, vnet_hdr = 0, i = 0, queues;
/* for the no-fd, no-helper case */
const char *script = NULL; /* suppress wrong "uninit'd use" gcc warning */
const char *downscript = NULL;
Error *err = NULL;
const char *vhostfdname;
char ifname[128];
int ret = 0;
assert(netdev->type == NET_CLIENT_DRIVER_TAP);
tap = &netdev->u.tap;
queues = tap->has_queues ? tap->queues : 1;
vhostfdname = tap->has_vhostfd ? tap->vhostfd : NULL;
/* QEMU hubs do not support multiqueue tap, in this case peer is set.
* For -netdev, peer is always NULL. */
if (peer && (tap->has_queues || tap->has_fds || tap->has_vhostfds)) {
error_setg(errp, "Multiqueue tap cannot be used with hubs");
return -1;
}
if (tap->has_fd) {
if (tap->has_ifname || tap->has_script || tap->has_downscript ||
tap->has_vnet_hdr || tap->has_helper || tap->has_queues ||
tap->has_fds || tap->has_vhostfds) {
error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
"helper=, queues=, fds=, and vhostfds= "
"are invalid with fd=");
return -1;
}
fd = monitor_fd_param(cur_mon, tap->fd, errp);
if (fd == -1) {
return -1;
}
ret = qemu_try_set_nonblock(fd);
if (ret < 0) {
error_setg_errno(errp, -ret, "%s: Can't use file descriptor %d",
name, fd);
return -1;
}
vnet_hdr = tap_probe_vnet_hdr(fd, errp);
if (vnet_hdr < 0) {
close(fd);
return -1;
}
net_init_tap_one(tap, peer, "tap", name, NULL,
script, downscript,
vhostfdname, vnet_hdr, fd, &err);
if (err) {
error_propagate(errp, err);
return -1;
}
} else if (tap->has_fds) {
char **fds;
char **vhost_fds;
int nfds = 0, nvhosts = 0;
if (tap->has_ifname || tap->has_script || tap->has_downscript ||
tap->has_vnet_hdr || tap->has_helper || tap->has_queues ||
tap->has_vhostfd) {
error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
"helper=, queues=, and vhostfd= "
"are invalid with fds=");
return -1;
}
fds = g_new0(char *, MAX_TAP_QUEUES);
vhost_fds = g_new0(char *, MAX_TAP_QUEUES);
nfds = get_fds(tap->fds, fds, MAX_TAP_QUEUES);
if (tap->has_vhostfds) {
nvhosts = get_fds(tap->vhostfds, vhost_fds, MAX_TAP_QUEUES);
if (nfds != nvhosts) {
error_setg(errp, "The number of fds passed does not match "
"the number of vhostfds passed");
ret = -1;
goto free_fail;
}
}
for (i = 0; i < nfds; i++) {
fd = monitor_fd_param(cur_mon, fds[i], errp);
if (fd == -1) {
ret = -1;
goto free_fail;
}
ret = qemu_try_set_nonblock(fd);
if (ret < 0) {
error_setg_errno(errp, -ret, "%s: Can't use file descriptor %d",
name, fd);
goto free_fail;
}
if (i == 0) {
vnet_hdr = tap_probe_vnet_hdr(fd, errp);
if (vnet_hdr < 0) {
goto free_fail;
}
} else if (vnet_hdr != tap_probe_vnet_hdr(fd, NULL)) {
error_setg(errp,
"vnet_hdr not consistent across given tap fds");
ret = -1;
goto free_fail;
}
net_init_tap_one(tap, peer, "tap", name, ifname,
script, downscript,
tap->has_vhostfds ? vhost_fds[i] : NULL,
vnet_hdr, fd, &err);
if (err) {
error_propagate(errp, err);
ret = -1;
goto free_fail;
}
}
free_fail:
for (i = 0; i < nvhosts; i++) {
g_free(vhost_fds[i]);
}
for (i = 0; i < nfds; i++) {
g_free(fds[i]);
}
g_free(fds);
g_free(vhost_fds);
return ret;
} else if (tap->has_helper) {
if (tap->has_ifname || tap->has_script || tap->has_downscript ||
tap->has_vnet_hdr || tap->has_queues || tap->has_vhostfds) {
error_setg(errp, "ifname=, script=, downscript=, vnet_hdr=, "
"queues=, and vhostfds= are invalid with helper=");
return -1;
}
fd = net_bridge_run_helper(tap->helper,
tap->has_br ?
tap->br : DEFAULT_BRIDGE_INTERFACE,
errp);
if (fd == -1) {
return -1;
}
qemu_set_nonblock(fd);
vnet_hdr = tap_probe_vnet_hdr(fd, errp);
if (vnet_hdr < 0) {
close(fd);
return -1;
}
net_init_tap_one(tap, peer, "bridge", name, ifname,
script, downscript, vhostfdname,
vnet_hdr, fd, &err);
if (err) {
error_propagate(errp, err);
close(fd);
return -1;
}
} else {
if (tap->has_vhostfds) {
error_setg(errp, "vhostfds= is invalid if fds= wasn't specified");
return -1;
}
script = tap->has_script ? tap->script : DEFAULT_NETWORK_SCRIPT;
downscript = tap->has_downscript ? tap->downscript :
DEFAULT_NETWORK_DOWN_SCRIPT;
if (tap->has_ifname) {
pstrcpy(ifname, sizeof ifname, tap->ifname);
} else {
ifname[0] = '\0';
}
for (i = 0; i < queues; i++) {
fd = net_tap_init(tap, &vnet_hdr, i >= 1 ? "no" : script,
ifname, sizeof ifname, queues > 1, errp);
if (fd == -1) {
return -1;
}
if (queues > 1 && i == 0 && !tap->has_ifname) {
if (tap_fd_get_ifname(fd, ifname)) {
error_setg(errp, "Fail to get ifname");
close(fd);
return -1;
}
}
net_init_tap_one(tap, peer, "tap", name, ifname,
i >= 1 ? "no" : script,
i >= 1 ? "no" : downscript,
vhostfdname, vnet_hdr, fd, &err);
if (err) {
error_propagate(errp, err);
close(fd);
return -1;
}
}
}
return 0;
}
VHostNetState *tap_get_vhost_net(NetClientState *nc)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
return s->vhost_net;
}
int tap_enable(NetClientState *nc)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
int ret;
if (s->enabled) {
return 0;
} else {
ret = tap_fd_enable(s->fd);
if (ret == 0) {
s->enabled = true;
tap_update_fd_handler(s);
}
return ret;
}
}
int tap_disable(NetClientState *nc)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
int ret;
if (s->enabled == 0) {
return 0;
} else {
ret = tap_fd_disable(s->fd);
if (ret == 0) {
qemu_purge_queued_packets(nc);
s->enabled = false;
tap_update_fd_handler(s);
}
return ret;
}
}