TUNSETSNDBUF is only available on linux
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

So I can add a tap-linux.c and use CONFIG_LINUX to pull it in
in Makefile
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Okay, this makes the tap options available on AIX even though there's
no support, but if we want to do it right we should have not compile
the tap code at all on AIX using e.g. CONFIG_TAP.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Also add a new net/checksum.h header
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

[v2: handle building in a separate dir]
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

This reverts commit 6cfa64de.

This breaks the monitor prompt.  Proper fix will come from Amit.
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

If we tell the guest we support UFO and then migrate to host which
doesn't support it, we will find ourselves in grave difficulties.

Prevent this scenario by adding a flag to virtio-net's savevm format
which indicates whether the device requires host UFO support.

[v2:
  - add has_ufo uint8_t field for ease of vmstate conversion
  - use qemu_error()
]
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Enable UFO on the host tap device if supported and allow setting UFO
on virtio-net in the guest.
Signed-off-by: NSridhar Samudrala <sri@us.ibm.com>
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

With the latest GSO/csum offload patches, any guest using an unpatched version
of dhclient (any Ubuntu guest, for instance), will no longer be able to get
a DHCP address.

dhclient is actually at fault here.  It uses AF_PACKET to receive DHCP responses
but does not check auxdata to see if the packet has a valid csum.  This causes
it to throw out the DHCP responses it gets from the virtio interface as there
is not a valid checksum.

Fedora has carried a patch to fix their dhclient (it's needed for Xen too) but
this patch has not made it into a release of dhclient.  AFAIK, the patch is in
the dhclient CVS but I cannot confirm since their CVS is not public.

This patch, suggested by Rusty, looks for UDP packets (of a normal MTU) and
explicitly adds a checksum to them if they are missing one.

This allows unpatched dhclients to continue to work without needing to update
the guest kernels.
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

We query the guest's feature set to see if it supports offload and,
if so, we enable those features on the tap interface.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

This API allows virtio-net to enable various offload features on a
tap interface - e.g. to tell the host kernel it can pass up partial
checksums to userspace.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

With '-netdev tap,id=foo -nic model=virtio,netdev=foo' virtio-net can
detect that its peer (i.e. the tap backend) supports vnet headers
and advertise to the guest that it can send packets with partial
checksums and/or TSO packets.

One complication is that if we're migrating and the source host
supports IFF_VNET_HDR but the destination host doesn't, we can't then
stop the guest from using those features. In this scenario, we just
fail the migration.

[v2:
 - add has_vnet_hdr uint32_t field for ease of vmstate conversion
 - use qemu_error()
]
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

tap_receive_raw() always prepends a vnet header if IFF_VNET_HDR is
enabled.

tap_receive() only prepends when the a header is required but the NIC
doesn't supply one.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Use qemu_send_packet_raw to send gratuitous arp. This will ensure that
vnet header is handled properly.

Also, avoid sending the gratuitous packet to the guest. There doesn't
appear to be any reason for doing that and the code will currently just
crash if the NIC is not associated with a vlan.
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Trivial patch to allow supplying a receive_raw function.

A future cleanup should combine this function pointer parameters into a
table.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

In the case where a NIC and backend agree on a packet header format,
this API allows injecting packets which lack the agreed upon header.

We need this for sending our gratuitous ARP.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

This allows for the addition of a raw flag, and leaves the way open
for other flags too.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

These lamely named functions allow virtio-net to query whether
IFF_VNET_HDR is enabled on a tap interface and inform the tap code
that virtio-net will supply packets with a vnet header.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

This is so as to allow APIs which operate on specific client types
without having to add a function table entry which is only implemented
by a single client type.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

This allows people to disable the IFF_VNET_HDR flag, e.g. for debugging
purposes or if they know they may migrate the guest to a machine without
IFF_VNET_HDR support.

It also allows making the lack of IFF_VNET_HDR support an error
condition, e.g. in the case where a guest is being migrated from a host
which does support it.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Re-factor things so that there is only one call site for
net_tap_fd_init().

Two concerns about the QemuOpts usage here - firstly, we set the script
arguments to their default value and, secondly, we set the ifname value
to the name allocated by the kernel if none is supplied. Are we okay
with such things ending up in writeconfig output?
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

For now, we just add an empty header before writing and strip the header
after reading.

We really only want IFF_VNET_HDR when virtio_net is using it, but it
would significantly complicate matters to try and do that. There should
be little or no performance impact with always adding headers.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

In future we will want to prepend a virtio_net header if the NIC didn't
supply one but IFF_VNET_HDR is enabled on the interface. This is most
easily achived by using writev() in all cases.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Making features dependent on the availability of newer versions if_tun.h
is going to get seriously clumsy, so let's just import the definitions
we need. It's only a small handful.

If and when we're comfortable depending on 2.6.30 headers, we can remove
this again.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Looks like these are just artifacts of vl.c being split up.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

It was merely a workaround and the real fix is done now.
This reverts commit ef845c3b.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Also for Linux AIO, don't call callbacks that don't belong to the active
AsyncContext.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Don't call callbacks that don't belong to the active AsyncContext.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

bdrv_read/write emulation is used as the perfect example why we need something
like AsyncContexts. So maybe they better start using it.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Add the possibility to use AIO and BHs without allowing foreign callbacks to be
run. Basically, you put your own AIOs and BHs in a separate context. For
details see the comments in the source.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Instead of putting more and more stuff into vl.c, let's have the generic
functions that deal with asynchronous callbacks in their own file.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>