qemu/net/tap.c

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/*
* 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>
net: Pad short frames to minimum size before sending from SLiRP/TAP The minimum Ethernet frame length is 60 bytes. For short frames with smaller length like ARP packets (only 42 bytes), on a real world NIC it can choose either padding its length to the minimum required 60 bytes, or sending it out directly to the wire. Such behavior can be hardcoded or controled by a register bit. Similarly on the receive path, NICs can choose either dropping such short frames directly or handing them over to software to handle. On the other hand, for the network backends like SLiRP/TAP, they don't expose a way to control the short frame behavior. As of today they just send/receive data from/to the other end connected to them, which means any sized packet is acceptable. So they can send and receive short frames without any problem. It is observed that ARP packets sent from SLiRP/TAP are 42 bytes, and SLiRP/TAP just send these ARP packets to the other end which might be a NIC model that does not allow short frames to pass through. To provide better compatibility, for packets sent from QEMU network backends like SLiRP/TAP, we change to pad short frames before sending it out to the other end, if the other end does not forbid it via the nc->do_not_pad flag. This ensures a backend as an Ethernet sender does not violate the spec. But with this change, the behavior of dropping short frames from SLiRP/TAP interfaces in the NIC model cannot be emulated because it always receives a packet that is spec complaint. The capability of sending short frames from NIC models is still supported and short frames can still pass through SLiRP/TAP. This commit should be able to fix the issue as reported with some NIC models before, that ARP requests get dropped, preventing the guest from becoming visible on the network. It was workarounded in these NIC models on the receive path, that when a short frame is received, it is padded up to 60 bytes. The following 2 commits seem to be the one to workaround this issue in e1000 and vmxenet3 before, and should probably be reverted. commit 78aeb23eded2 ("e1000: Pad short frames to minimum size (60 bytes)") commit 40a87c6c9b11 ("vmxnet3: Pad short frames to minimum size (60 bytes)") Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
2021-03-17 06:26:29 +00:00
#include "net/eth.h"
#include "net/net.h"
#include "clients.h"
#include "monitor/monitor.h"
#include "sysemu/sysemu.h"
2016-03-14 08:01:28 +00:00
#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;
net: Pad short frames to minimum size before sending from SLiRP/TAP The minimum Ethernet frame length is 60 bytes. For short frames with smaller length like ARP packets (only 42 bytes), on a real world NIC it can choose either padding its length to the minimum required 60 bytes, or sending it out directly to the wire. Such behavior can be hardcoded or controled by a register bit. Similarly on the receive path, NICs can choose either dropping such short frames directly or handing them over to software to handle. On the other hand, for the network backends like SLiRP/TAP, they don't expose a way to control the short frame behavior. As of today they just send/receive data from/to the other end connected to them, which means any sized packet is acceptable. So they can send and receive short frames without any problem. It is observed that ARP packets sent from SLiRP/TAP are 42 bytes, and SLiRP/TAP just send these ARP packets to the other end which might be a NIC model that does not allow short frames to pass through. To provide better compatibility, for packets sent from QEMU network backends like SLiRP/TAP, we change to pad short frames before sending it out to the other end, if the other end does not forbid it via the nc->do_not_pad flag. This ensures a backend as an Ethernet sender does not violate the spec. But with this change, the behavior of dropping short frames from SLiRP/TAP interfaces in the NIC model cannot be emulated because it always receives a packet that is spec complaint. The capability of sending short frames from NIC models is still supported and short frames can still pass through SLiRP/TAP. This commit should be able to fix the issue as reported with some NIC models before, that ARP requests get dropped, preventing the guest from becoming visible on the network. It was workarounded in these NIC models on the receive path, that when a short frame is received, it is padded up to 60 bytes. The following 2 commits seem to be the one to workaround this issue in e1000 and vmxenet3 before, and should probably be reverted. commit 78aeb23eded2 ("e1000: Pad short frames to minimum size (60 bytes)") commit 40a87c6c9b11 ("vmxnet3: Pad short frames to minimum size (60 bytes)") Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
2021-03-17 06:26:29 +00:00
uint8_t min_pkt[ETH_ZLEN];
size_t min_pktsz = sizeof(min_pkt);
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;
}
if (net_peer_needs_padding(&s->nc)) {
net: Pad short frames to minimum size before sending from SLiRP/TAP The minimum Ethernet frame length is 60 bytes. For short frames with smaller length like ARP packets (only 42 bytes), on a real world NIC it can choose either padding its length to the minimum required 60 bytes, or sending it out directly to the wire. Such behavior can be hardcoded or controled by a register bit. Similarly on the receive path, NICs can choose either dropping such short frames directly or handing them over to software to handle. On the other hand, for the network backends like SLiRP/TAP, they don't expose a way to control the short frame behavior. As of today they just send/receive data from/to the other end connected to them, which means any sized packet is acceptable. So they can send and receive short frames without any problem. It is observed that ARP packets sent from SLiRP/TAP are 42 bytes, and SLiRP/TAP just send these ARP packets to the other end which might be a NIC model that does not allow short frames to pass through. To provide better compatibility, for packets sent from QEMU network backends like SLiRP/TAP, we change to pad short frames before sending it out to the other end, if the other end does not forbid it via the nc->do_not_pad flag. This ensures a backend as an Ethernet sender does not violate the spec. But with this change, the behavior of dropping short frames from SLiRP/TAP interfaces in the NIC model cannot be emulated because it always receives a packet that is spec complaint. The capability of sending short frames from NIC models is still supported and short frames can still pass through SLiRP/TAP. This commit should be able to fix the issue as reported with some NIC models before, that ARP requests get dropped, preventing the guest from becoming visible on the network. It was workarounded in these NIC models on the receive path, that when a short frame is received, it is padded up to 60 bytes. The following 2 commits seem to be the one to workaround this issue in e1000 and vmxenet3 before, and should probably be reverted. commit 78aeb23eded2 ("e1000: Pad short frames to minimum size (60 bytes)") commit 40a87c6c9b11 ("vmxnet3: Pad short frames to minimum size (60 bytes)") Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
2021-03-17 06:26:29 +00:00
if (eth_pad_short_frame(min_pkt, &min_pktsz, buf, size)) {
buf = min_pkt;
size = min_pktsz;
}
}
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);
qapi: Change Netdev into a flat union This is a mostly-mechanical conversion that creates a new flat union 'Netdev' QAPI type that covers all the branches of the former 'NetClientOptions' simple union, where the branches are now listed in a new 'NetClientDriver' enum rather than generated from the simple union. The existence of a flat union has no change to the command line syntax accepted for new code, and will make it possible for a future patch to switch the QMP command to parse a boxed union for no change to valid QMP; but it does have some ripple effect on the C code when dealing with the new types. While making the conversion, note that the 'NetLegacy' type remains unchanged: it applies only to legacy command line options, and will not be ported to QMP, so it should remain a wrapper around a simple union; to avoid confusion, the type named 'NetClientOptions' is now gone, and we introduce 'NetLegacyOptions' in its place. Then, in the C code, we convert from NetLegacy to Netdev as soon as possible, so that the bulk of the net stack only has to deal with one QAPI type, not two. Note that since the old legacy code always rejected 'hubport', we can just omit that branch from the new 'NetLegacyOptions' simple union. Based on an idea originally by Zoltán Kővágó <DirtY.iCE.hu@gmail.com>: Message-Id: <01a527fbf1a5de880091f98cf011616a78adeeee.1441627176.git.DirtY.iCE.hu@gmail.com> although the sed script in that patch no longer applies due to other changes in the tree since then, and I also did some manual cleanups (such as fixing whitespace to keep checkpatch happy). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1468468228-27827-13-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Fixup from Eric squashed in] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-14 03:50:23 +00:00
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);
qapi: Change Netdev into a flat union This is a mostly-mechanical conversion that creates a new flat union 'Netdev' QAPI type that covers all the branches of the former 'NetClientOptions' simple union, where the branches are now listed in a new 'NetClientDriver' enum rather than generated from the simple union. The existence of a flat union has no change to the command line syntax accepted for new code, and will make it possible for a future patch to switch the QMP command to parse a boxed union for no change to valid QMP; but it does have some ripple effect on the C code when dealing with the new types. While making the conversion, note that the 'NetLegacy' type remains unchanged: it applies only to legacy command line options, and will not be ported to QMP, so it should remain a wrapper around a simple union; to avoid confusion, the type named 'NetClientOptions' is now gone, and we introduce 'NetLegacyOptions' in its place. Then, in the C code, we convert from NetLegacy to Netdev as soon as possible, so that the bulk of the net stack only has to deal with one QAPI type, not two. Note that since the old legacy code always rejected 'hubport', we can just omit that branch from the new 'NetLegacyOptions' simple union. Based on an idea originally by Zoltán Kővágó <DirtY.iCE.hu@gmail.com>: Message-Id: <01a527fbf1a5de880091f98cf011616a78adeeee.1441627176.git.DirtY.iCE.hu@gmail.com> although the sed script in that patch no longer applies due to other changes in the tree since then, and I also did some manual cleanups (such as fixing whitespace to keep checkpatch happy). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1468468228-27827-13-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Fixup from Eric squashed in] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-14 03:50:23 +00:00
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);
qapi: Change Netdev into a flat union This is a mostly-mechanical conversion that creates a new flat union 'Netdev' QAPI type that covers all the branches of the former 'NetClientOptions' simple union, where the branches are now listed in a new 'NetClientDriver' enum rather than generated from the simple union. The existence of a flat union has no change to the command line syntax accepted for new code, and will make it possible for a future patch to switch the QMP command to parse a boxed union for no change to valid QMP; but it does have some ripple effect on the C code when dealing with the new types. While making the conversion, note that the 'NetLegacy' type remains unchanged: it applies only to legacy command line options, and will not be ported to QMP, so it should remain a wrapper around a simple union; to avoid confusion, the type named 'NetClientOptions' is now gone, and we introduce 'NetLegacyOptions' in its place. Then, in the C code, we convert from NetLegacy to Netdev as soon as possible, so that the bulk of the net stack only has to deal with one QAPI type, not two. Note that since the old legacy code always rejected 'hubport', we can just omit that branch from the new 'NetLegacyOptions' simple union. Based on an idea originally by Zoltán Kővágó <DirtY.iCE.hu@gmail.com>: Message-Id: <01a527fbf1a5de880091f98cf011616a78adeeee.1441627176.git.DirtY.iCE.hu@gmail.com> although the sed script in that patch no longer applies due to other changes in the tree since then, and I also did some manual cleanups (such as fixing whitespace to keep checkpatch happy). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1468468228-27827-13-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Fixup from Eric squashed in] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-14 03:50:23 +00:00
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);
qapi: Change Netdev into a flat union This is a mostly-mechanical conversion that creates a new flat union 'Netdev' QAPI type that covers all the branches of the former 'NetClientOptions' simple union, where the branches are now listed in a new 'NetClientDriver' enum rather than generated from the simple union. The existence of a flat union has no change to the command line syntax accepted for new code, and will make it possible for a future patch to switch the QMP command to parse a boxed union for no change to valid QMP; but it does have some ripple effect on the C code when dealing with the new types. While making the conversion, note that the 'NetLegacy' type remains unchanged: it applies only to legacy command line options, and will not be ported to QMP, so it should remain a wrapper around a simple union; to avoid confusion, the type named 'NetClientOptions' is now gone, and we introduce 'NetLegacyOptions' in its place. Then, in the C code, we convert from NetLegacy to Netdev as soon as possible, so that the bulk of the net stack only has to deal with one QAPI type, not two. Note that since the old legacy code always rejected 'hubport', we can just omit that branch from the new 'NetLegacyOptions' simple union. Based on an idea originally by Zoltán Kővágó <DirtY.iCE.hu@gmail.com>: Message-Id: <01a527fbf1a5de880091f98cf011616a78adeeee.1441627176.git.DirtY.iCE.hu@gmail.com> although the sed script in that patch no longer applies due to other changes in the tree since then, and I also did some manual cleanups (such as fixing whitespace to keep checkpatch happy). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1468468228-27827-13-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Fixup from Eric squashed in] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-14 03:50:23 +00:00
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);
qapi: Change Netdev into a flat union This is a mostly-mechanical conversion that creates a new flat union 'Netdev' QAPI type that covers all the branches of the former 'NetClientOptions' simple union, where the branches are now listed in a new 'NetClientDriver' enum rather than generated from the simple union. The existence of a flat union has no change to the command line syntax accepted for new code, and will make it possible for a future patch to switch the QMP command to parse a boxed union for no change to valid QMP; but it does have some ripple effect on the C code when dealing with the new types. While making the conversion, note that the 'NetLegacy' type remains unchanged: it applies only to legacy command line options, and will not be ported to QMP, so it should remain a wrapper around a simple union; to avoid confusion, the type named 'NetClientOptions' is now gone, and we introduce 'NetLegacyOptions' in its place. Then, in the C code, we convert from NetLegacy to Netdev as soon as possible, so that the bulk of the net stack only has to deal with one QAPI type, not two. Note that since the old legacy code always rejected 'hubport', we can just omit that branch from the new 'NetLegacyOptions' simple union. Based on an idea originally by Zoltán Kővágó <DirtY.iCE.hu@gmail.com>: Message-Id: <01a527fbf1a5de880091f98cf011616a78adeeee.1441627176.git.DirtY.iCE.hu@gmail.com> although the sed script in that patch no longer applies due to other changes in the tree since then, and I also did some manual cleanups (such as fixing whitespace to keep checkpatch happy). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1468468228-27827-13-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Fixup from Eric squashed in] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-14 03:50:23 +00:00
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);
}
static bool tap_set_steering_ebpf(NetClientState *nc, int prog_fd)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
return tap_fd_set_steering_ebpf(s->fd, prog_fd) == 0;
}
int tap_get_fd(NetClientState *nc)
{
TAPState *s = DO_UPCAST(TAPState, nc, nc);
qapi: Change Netdev into a flat union This is a mostly-mechanical conversion that creates a new flat union 'Netdev' QAPI type that covers all the branches of the former 'NetClientOptions' simple union, where the branches are now listed in a new 'NetClientDriver' enum rather than generated from the simple union. The existence of a flat union has no change to the command line syntax accepted for new code, and will make it possible for a future patch to switch the QMP command to parse a boxed union for no change to valid QMP; but it does have some ripple effect on the C code when dealing with the new types. While making the conversion, note that the 'NetLegacy' type remains unchanged: it applies only to legacy command line options, and will not be ported to QMP, so it should remain a wrapper around a simple union; to avoid confusion, the type named 'NetClientOptions' is now gone, and we introduce 'NetLegacyOptions' in its place. Then, in the C code, we convert from NetLegacy to Netdev as soon as possible, so that the bulk of the net stack only has to deal with one QAPI type, not two. Note that since the old legacy code always rejected 'hubport', we can just omit that branch from the new 'NetLegacyOptions' simple union. Based on an idea originally by Zoltán Kővágó <DirtY.iCE.hu@gmail.com>: Message-Id: <01a527fbf1a5de880091f98cf011616a78adeeee.1441627176.git.DirtY.iCE.hu@gmail.com> although the sed script in that patch no longer applies due to other changes in the tree since then, and I also did some manual cleanups (such as fixing whitespace to keep checkpatch happy). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1468468228-27827-13-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Fixup from Eric squashed in] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-14 03:50:23 +00:00
assert(nc->info->type == NET_CLIENT_DRIVER_TAP);
return s->fd;
}
/* fd support */
static NetClientInfo net_tap_info = {
qapi: Change Netdev into a flat union This is a mostly-mechanical conversion that creates a new flat union 'Netdev' QAPI type that covers all the branches of the former 'NetClientOptions' simple union, where the branches are now listed in a new 'NetClientDriver' enum rather than generated from the simple union. The existence of a flat union has no change to the command line syntax accepted for new code, and will make it possible for a future patch to switch the QMP command to parse a boxed union for no change to valid QMP; but it does have some ripple effect on the C code when dealing with the new types. While making the conversion, note that the 'NetLegacy' type remains unchanged: it applies only to legacy command line options, and will not be ported to QMP, so it should remain a wrapper around a simple union; to avoid confusion, the type named 'NetClientOptions' is now gone, and we introduce 'NetLegacyOptions' in its place. Then, in the C code, we convert from NetLegacy to Netdev as soon as possible, so that the bulk of the net stack only has to deal with one QAPI type, not two. Note that since the old legacy code always rejected 'hubport', we can just omit that branch from the new 'NetLegacyOptions' simple union. Based on an idea originally by Zoltán Kővágó <DirtY.iCE.hu@gmail.com>: Message-Id: <01a527fbf1a5de880091f98cf011616a78adeeee.1441627176.git.DirtY.iCE.hu@gmail.com> although the sed script in that patch no longer applies due to other changes in the tree since then, and I also did some manual cleanups (such as fixing whitespace to keep checkpatch happy). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1468468228-27827-13-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Fixup from Eric squashed in] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-14 03:50:23 +00:00
.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,
.set_steering_ebpf = tap_set_steering_ebpf,
};
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);
}
}
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
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)
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
{
sigset_t oldmask, mask;
g_autofree char *default_helper = NULL;
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
int pid, status;
char *args[5];
char **parg;
int sv[2];
sigemptyset(&mask);
sigaddset(&mask, SIGCHLD);
sigprocmask(SIG_BLOCK, &mask, &oldmask);
if (!helper) {
helper = default_helper = get_relocated_path(DEFAULT_BRIDGE_HELPER);
}
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) == -1) {
error_setg_errno(errp, errno, "socketpair() failed");
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
return -1;
}
/* try to launch bridge helper */
pid = fork();
if (pid < 0) {
error_setg_errno(errp, errno, "Can't fork bridge helper");
return -1;
}
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
if (pid == 0) {
int open_max = sysconf(_SC_OPEN_MAX), i;
char *fd_buf = NULL;
char *br_buf = NULL;
char *helper_cmd = NULL;
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
for (i = 3; i < open_max; i++) {
if (i != sv[1]) {
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
close(i);
}
}
fd_buf = g_strdup_printf("%s%d", "--fd=", sv[1]);
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
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);
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
}
helper_cmd = g_strdup_printf("%s %s %s %s", helper,
"--use-vnet", fd_buf, br_buf ? br_buf : "");
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
parg = args;
*parg++ = (char *)"sh";
*parg++ = (char *)"-c";
*parg++ = helper_cmd;
*parg++ = NULL;
execv("/bin/sh", args);
g_free(helper_cmd);
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
} else {
/* assume helper is just the executable path name */
br_buf = g_strdup_printf("%s%s", "--br=", bridge);
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
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);
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
_exit(1);
} else {
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
int fd;
int saved_errno;
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
close(sv[1]);
do {
fd = recv_fd(sv[0]);
} while (fd == -1 && errno == EINTR);
saved_errno = errno;
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
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");
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
return -1;
}
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
error_setg(errp, "bridge helper failed");
return -1;
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
}
return fd;
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
}
}
int net_init_bridge(const Netdev *netdev, const char *name,
NetClientState *peer, Error **errp)
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
{
const NetdevBridgeOptions *bridge;
const char *helper, *br;
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
TAPState *s;
int fd, vnet_hdr;
qapi: Change Netdev into a flat union This is a mostly-mechanical conversion that creates a new flat union 'Netdev' QAPI type that covers all the branches of the former 'NetClientOptions' simple union, where the branches are now listed in a new 'NetClientDriver' enum rather than generated from the simple union. The existence of a flat union has no change to the command line syntax accepted for new code, and will make it possible for a future patch to switch the QMP command to parse a boxed union for no change to valid QMP; but it does have some ripple effect on the C code when dealing with the new types. While making the conversion, note that the 'NetLegacy' type remains unchanged: it applies only to legacy command line options, and will not be ported to QMP, so it should remain a wrapper around a simple union; to avoid confusion, the type named 'NetClientOptions' is now gone, and we introduce 'NetLegacyOptions' in its place. Then, in the C code, we convert from NetLegacy to Netdev as soon as possible, so that the bulk of the net stack only has to deal with one QAPI type, not two. Note that since the old legacy code always rejected 'hubport', we can just omit that branch from the new 'NetLegacyOptions' simple union. Based on an idea originally by Zoltán Kővágó <DirtY.iCE.hu@gmail.com>: Message-Id: <01a527fbf1a5de880091f98cf011616a78adeeee.1441627176.git.DirtY.iCE.hu@gmail.com> although the sed script in that patch no longer applies due to other changes in the tree since then, and I also did some manual cleanups (such as fixing whitespace to keep checkpatch happy). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1468468228-27827-13-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Fixup from Eric squashed in] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-14 03:50:23 +00:00
assert(netdev->type == NET_CLIENT_DRIVER_BRIDGE);
bridge = &netdev->u.bridge;
helper = bridge->has_helper ? bridge->helper : NULL;
br = bridge->has_br ? bridge->br : DEFAULT_BRIDGE_INTERFACE;
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
fd = net_bridge_run_helper(helper, br, errp);
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
if (fd == -1) {
return -1;
}
qemu_set_nonblock(fd);
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>
2020-07-07 18:45:15 +00:00
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);
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
snprintf(s->nc.info_str, sizeof(s->nc.info_str), "helper=%s,br=%s", helper,
br);
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
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) {
net: check if the file descriptor is valid before using it qemu_set_nonblock() checks that the file descriptor can be used and, if not, crashes QEMU. An assert() is used for that. The use of assert() is used to detect programming error and the coredump will allow to debug the problem. But in the case of the tap device, this assert() can be triggered by a misconfiguration by the user. At startup, it's not a real problem, but it can also happen during the hot-plug of a new device, and here it's a problem because we can crash a perfectly healthy system. For instance: # ip link add link virbr0 name macvtap0 type macvtap mode bridge # ip link set macvtap0 up # TAP=/dev/tap$(ip -o link show macvtap0 | cut -d: -f1) # qemu-system-x86_64 -machine q35 -device pcie-root-port,id=pcie-root-port-0 -monitor stdio 9<> $TAP (qemu) netdev_add type=tap,id=hostnet0,vhost=on,fd=9 (qemu) device_add driver=virtio-net-pci,netdev=hostnet0,id=net0,bus=pcie-root-port-0 (qemu) device_del net0 (qemu) netdev_del hostnet0 (qemu) netdev_add type=tap,id=hostnet1,vhost=on,fd=9 qemu-system-x86_64: .../util/oslib-posix.c:247: qemu_set_nonblock: Assertion `f != -1' failed. Aborted (core dumped) To avoid that, add a function, qemu_try_set_nonblock(), that allows to report the problem without crashing. In the same way, we also update the function for vhostfd in net_init_tap_one() and for fd in net_init_socket() (both descriptors are provided by the user and can be wrong). Signed-off-by: Laurent Vivier <lvivier@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
2020-07-07 18:45:14 +00:00
int ret;
vhostfd = monitor_fd_param(monitor_cur(), vhostfdname, &err);
if (vhostfd == -1) {
if (tap->has_vhostforce && tap->vhostforce) {
error_propagate(errp, err);
} else {
warn_report_err(err);
}
return;
}
net: check if the file descriptor is valid before using it qemu_set_nonblock() checks that the file descriptor can be used and, if not, crashes QEMU. An assert() is used for that. The use of assert() is used to detect programming error and the coredump will allow to debug the problem. But in the case of the tap device, this assert() can be triggered by a misconfiguration by the user. At startup, it's not a real problem, but it can also happen during the hot-plug of a new device, and here it's a problem because we can crash a perfectly healthy system. For instance: # ip link add link virbr0 name macvtap0 type macvtap mode bridge # ip link set macvtap0 up # TAP=/dev/tap$(ip -o link show macvtap0 | cut -d: -f1) # qemu-system-x86_64 -machine q35 -device pcie-root-port,id=pcie-root-port-0 -monitor stdio 9<> $TAP (qemu) netdev_add type=tap,id=hostnet0,vhost=on,fd=9 (qemu) device_add driver=virtio-net-pci,netdev=hostnet0,id=net0,bus=pcie-root-port-0 (qemu) device_del net0 (qemu) netdev_del hostnet0 (qemu) netdev_add type=tap,id=hostnet1,vhost=on,fd=9 qemu-system-x86_64: .../util/oslib-posix.c:247: qemu_set_nonblock: Assertion `f != -1' failed. Aborted (core dumped) To avoid that, add a function, qemu_try_set_nonblock(), that allows to report the problem without crashing. In the same way, we also update the function for vhostfd in net_init_tap_one() and for fd in net_init_socket() (both descriptors are provided by the user and can be wrong). Signed-off-by: Laurent Vivier <lvivier@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
2020-07-07 18:45:14 +00:00
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;
options.nvqs = 2;
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;
const char *downscript;
Error *err = NULL;
const char *vhostfdname;
char ifname[128];
net: check if the file descriptor is valid before using it qemu_set_nonblock() checks that the file descriptor can be used and, if not, crashes QEMU. An assert() is used for that. The use of assert() is used to detect programming error and the coredump will allow to debug the problem. But in the case of the tap device, this assert() can be triggered by a misconfiguration by the user. At startup, it's not a real problem, but it can also happen during the hot-plug of a new device, and here it's a problem because we can crash a perfectly healthy system. For instance: # ip link add link virbr0 name macvtap0 type macvtap mode bridge # ip link set macvtap0 up # TAP=/dev/tap$(ip -o link show macvtap0 | cut -d: -f1) # qemu-system-x86_64 -machine q35 -device pcie-root-port,id=pcie-root-port-0 -monitor stdio 9<> $TAP (qemu) netdev_add type=tap,id=hostnet0,vhost=on,fd=9 (qemu) device_add driver=virtio-net-pci,netdev=hostnet0,id=net0,bus=pcie-root-port-0 (qemu) device_del net0 (qemu) netdev_del hostnet0 (qemu) netdev_add type=tap,id=hostnet1,vhost=on,fd=9 qemu-system-x86_64: .../util/oslib-posix.c:247: qemu_set_nonblock: Assertion `f != -1' failed. Aborted (core dumped) To avoid that, add a function, qemu_try_set_nonblock(), that allows to report the problem without crashing. In the same way, we also update the function for vhostfd in net_init_tap_one() and for fd in net_init_socket() (both descriptors are provided by the user and can be wrong). Signed-off-by: Laurent Vivier <lvivier@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
2020-07-07 18:45:14 +00:00
int ret = 0;
qapi: Change Netdev into a flat union This is a mostly-mechanical conversion that creates a new flat union 'Netdev' QAPI type that covers all the branches of the former 'NetClientOptions' simple union, where the branches are now listed in a new 'NetClientDriver' enum rather than generated from the simple union. The existence of a flat union has no change to the command line syntax accepted for new code, and will make it possible for a future patch to switch the QMP command to parse a boxed union for no change to valid QMP; but it does have some ripple effect on the C code when dealing with the new types. While making the conversion, note that the 'NetLegacy' type remains unchanged: it applies only to legacy command line options, and will not be ported to QMP, so it should remain a wrapper around a simple union; to avoid confusion, the type named 'NetClientOptions' is now gone, and we introduce 'NetLegacyOptions' in its place. Then, in the C code, we convert from NetLegacy to Netdev as soon as possible, so that the bulk of the net stack only has to deal with one QAPI type, not two. Note that since the old legacy code always rejected 'hubport', we can just omit that branch from the new 'NetLegacyOptions' simple union. Based on an idea originally by Zoltán Kővágó <DirtY.iCE.hu@gmail.com>: Message-Id: <01a527fbf1a5de880091f98cf011616a78adeeee.1441627176.git.DirtY.iCE.hu@gmail.com> although the sed script in that patch no longer applies due to other changes in the tree since then, and I also did some manual cleanups (such as fixing whitespace to keep checkpatch happy). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1468468228-27827-13-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Fixup from Eric squashed in] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-14 03:50:23 +00:00
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;
script = tap->has_script ? tap->script : NULL;
downscript = tap->has_downscript ? tap->downscript : 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(monitor_cur(), tap->fd, errp);
if (fd == -1) {
return -1;
}
net: check if the file descriptor is valid before using it qemu_set_nonblock() checks that the file descriptor can be used and, if not, crashes QEMU. An assert() is used for that. The use of assert() is used to detect programming error and the coredump will allow to debug the problem. But in the case of the tap device, this assert() can be triggered by a misconfiguration by the user. At startup, it's not a real problem, but it can also happen during the hot-plug of a new device, and here it's a problem because we can crash a perfectly healthy system. For instance: # ip link add link virbr0 name macvtap0 type macvtap mode bridge # ip link set macvtap0 up # TAP=/dev/tap$(ip -o link show macvtap0 | cut -d: -f1) # qemu-system-x86_64 -machine q35 -device pcie-root-port,id=pcie-root-port-0 -monitor stdio 9<> $TAP (qemu) netdev_add type=tap,id=hostnet0,vhost=on,fd=9 (qemu) device_add driver=virtio-net-pci,netdev=hostnet0,id=net0,bus=pcie-root-port-0 (qemu) device_del net0 (qemu) netdev_del hostnet0 (qemu) netdev_add type=tap,id=hostnet1,vhost=on,fd=9 qemu-system-x86_64: .../util/oslib-posix.c:247: qemu_set_nonblock: Assertion `f != -1' failed. Aborted (core dumped) To avoid that, add a function, qemu_try_set_nonblock(), that allows to report the problem without crashing. In the same way, we also update the function for vhostfd in net_init_tap_one() and for fd in net_init_socket() (both descriptors are provided by the user and can be wrong). Signed-off-by: Laurent Vivier <lvivier@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
2020-07-07 18:45:14 +00:00
ret = qemu_try_set_nonblock(fd);
if (ret < 0) {
error_setg_errno(errp, -ret, "%s: Can't use file descriptor %d",
name, fd);
close(fd);
net: check if the file descriptor is valid before using it qemu_set_nonblock() checks that the file descriptor can be used and, if not, crashes QEMU. An assert() is used for that. The use of assert() is used to detect programming error and the coredump will allow to debug the problem. But in the case of the tap device, this assert() can be triggered by a misconfiguration by the user. At startup, it's not a real problem, but it can also happen during the hot-plug of a new device, and here it's a problem because we can crash a perfectly healthy system. For instance: # ip link add link virbr0 name macvtap0 type macvtap mode bridge # ip link set macvtap0 up # TAP=/dev/tap$(ip -o link show macvtap0 | cut -d: -f1) # qemu-system-x86_64 -machine q35 -device pcie-root-port,id=pcie-root-port-0 -monitor stdio 9<> $TAP (qemu) netdev_add type=tap,id=hostnet0,vhost=on,fd=9 (qemu) device_add driver=virtio-net-pci,netdev=hostnet0,id=net0,bus=pcie-root-port-0 (qemu) device_del net0 (qemu) netdev_del hostnet0 (qemu) netdev_add type=tap,id=hostnet1,vhost=on,fd=9 qemu-system-x86_64: .../util/oslib-posix.c:247: qemu_set_nonblock: Assertion `f != -1' failed. Aborted (core dumped) To avoid that, add a function, qemu_try_set_nonblock(), that allows to report the problem without crashing. In the same way, we also update the function for vhostfd in net_init_tap_one() and for fd in net_init_socket() (both descriptors are provided by the user and can be wrong). Signed-off-by: Laurent Vivier <lvivier@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
2020-07-07 18:45:14 +00:00
return -1;
}
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>
2020-07-07 18:45:15 +00:00
vnet_hdr = tap_probe_vnet_hdr(fd, errp);
if (vnet_hdr < 0) {
close(fd);
return -1;
}
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
net_init_tap_one(tap, peer, "tap", name, NULL,
script, downscript,
vhostfdname, vnet_hdr, fd, &err);
if (err) {
error_propagate(errp, err);
close(fd);
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(monitor_cur(), fds[i], errp);
if (fd == -1) {
ret = -1;
goto free_fail;
}
net: check if the file descriptor is valid before using it qemu_set_nonblock() checks that the file descriptor can be used and, if not, crashes QEMU. An assert() is used for that. The use of assert() is used to detect programming error and the coredump will allow to debug the problem. But in the case of the tap device, this assert() can be triggered by a misconfiguration by the user. At startup, it's not a real problem, but it can also happen during the hot-plug of a new device, and here it's a problem because we can crash a perfectly healthy system. For instance: # ip link add link virbr0 name macvtap0 type macvtap mode bridge # ip link set macvtap0 up # TAP=/dev/tap$(ip -o link show macvtap0 | cut -d: -f1) # qemu-system-x86_64 -machine q35 -device pcie-root-port,id=pcie-root-port-0 -monitor stdio 9<> $TAP (qemu) netdev_add type=tap,id=hostnet0,vhost=on,fd=9 (qemu) device_add driver=virtio-net-pci,netdev=hostnet0,id=net0,bus=pcie-root-port-0 (qemu) device_del net0 (qemu) netdev_del hostnet0 (qemu) netdev_add type=tap,id=hostnet1,vhost=on,fd=9 qemu-system-x86_64: .../util/oslib-posix.c:247: qemu_set_nonblock: Assertion `f != -1' failed. Aborted (core dumped) To avoid that, add a function, qemu_try_set_nonblock(), that allows to report the problem without crashing. In the same way, we also update the function for vhostfd in net_init_tap_one() and for fd in net_init_socket() (both descriptors are provided by the user and can be wrong). Signed-off-by: Laurent Vivier <lvivier@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
2020-07-07 18:45:14 +00:00
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;
}
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
if (i == 0) {
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>
2020-07-07 18:45:15 +00:00
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=");
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
return -1;
}
fd = net_bridge_run_helper(tap->helper,
tap->has_br ?
tap->br : DEFAULT_BRIDGE_INTERFACE,
errp);
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
if (fd == -1) {
return -1;
}
qemu_set_nonblock(fd);
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>
2020-07-07 18:45:15 +00:00
vnet_hdr = tap_probe_vnet_hdr(fd, errp);
if (vnet_hdr < 0) {
close(fd);
return -1;
}
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
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 {
g_autofree char *default_script = NULL;
g_autofree char *default_downscript = NULL;
if (tap->has_vhostfds) {
error_setg(errp, "vhostfds= is invalid if fds= wasn't specified");
return -1;
}
if (!script) {
script = default_script = get_relocated_path(DEFAULT_NETWORK_SCRIPT);
}
if (!downscript) {
downscript = default_downscript =
get_relocated_path(DEFAULT_NETWORK_DOWN_SCRIPT);
}
if (tap->has_ifname) {
pstrcpy(ifname, sizeof ifname, tap->ifname);
} else {
ifname[0] = '\0';
}
Add support for net bridge The most common use of -net tap is to connect a tap device to a bridge. This requires the use of a script and running qemu as root in order to allocate a tap device to pass to the script. This model is great for portability and flexibility but it's incredibly difficult to eliminate the need to run qemu as root. The only really viable mechanism is to use tunctl to create a tap device, attach it to a bridge as root, and then hand that tap device to qemu. The problem with this mechanism is that it requires administrator intervention whenever a user wants to create a guest. By essentially writing a helper that implements the most common qemu-ifup script that can be safely given cap_net_admin, we can dramatically simplify things for non-privileged users. We still support existing -net tap options as a mechanism for advanced users and backwards compatibility. Currently, this is very Linux centric but there's really no reason why it couldn't be extended for other Unixes. A typical invocation would be similar to one of the following: qemu linux.img -net bridge -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper" -net nic,model=virtio qemu linux.img -netdev bridge,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 The default bridge that we attach to is br0. The thinking is that a distro could preconfigure such an interface to allow out-of-the-box bridged networking. Alternatively, if a user wants to use a different bridge, a typical invocation would be simliar to one of the following: qemu linux.img -net bridge,br=qemubr0 -net nic,model=virtio qemu linux.img -net tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0" -net nic,model=virtio qemu linux.img -netdev bridge,br=qemubr0,id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 qemu linux.img -netdev tap,helper="/usr/local/libexec/qemu-bridge-helper --br=qemubr0",id=hn0 -device virtio-net-pci,netdev=hn0,id=nic1 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Richa Marwaha <rmarwah@linux.vnet.ibm.com> Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-01-26 14:42:27 +00:00
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);
qapi: Change Netdev into a flat union This is a mostly-mechanical conversion that creates a new flat union 'Netdev' QAPI type that covers all the branches of the former 'NetClientOptions' simple union, where the branches are now listed in a new 'NetClientDriver' enum rather than generated from the simple union. The existence of a flat union has no change to the command line syntax accepted for new code, and will make it possible for a future patch to switch the QMP command to parse a boxed union for no change to valid QMP; but it does have some ripple effect on the C code when dealing with the new types. While making the conversion, note that the 'NetLegacy' type remains unchanged: it applies only to legacy command line options, and will not be ported to QMP, so it should remain a wrapper around a simple union; to avoid confusion, the type named 'NetClientOptions' is now gone, and we introduce 'NetLegacyOptions' in its place. Then, in the C code, we convert from NetLegacy to Netdev as soon as possible, so that the bulk of the net stack only has to deal with one QAPI type, not two. Note that since the old legacy code always rejected 'hubport', we can just omit that branch from the new 'NetLegacyOptions' simple union. Based on an idea originally by Zoltán Kővágó <DirtY.iCE.hu@gmail.com>: Message-Id: <01a527fbf1a5de880091f98cf011616a78adeeee.1441627176.git.DirtY.iCE.hu@gmail.com> although the sed script in that patch no longer applies due to other changes in the tree since then, and I also did some manual cleanups (such as fixing whitespace to keep checkpatch happy). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1468468228-27827-13-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Fixup from Eric squashed in] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-14 03:50:23 +00:00
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;
}
}