linux-stable.git/drivers/net/tun.c, branch linux-3.14.y

tun: Fix csum_start with VLAN acceleration

2014-11-21T17:23:01+00:00

commit a8f9bfdf982e2b1fb9f094e4de9ab08c57f3d2fd upstream.

When VLAN acceleration is in use on the xmit path, we end up
setting csum_start to the wrong place.  The result is that the
whoever ends up doing the checksum setting will corrupt the packet
instead of writing the checksum to the expected location, usually
this means writing the checksum with an offset of -4.

This patch fixes this by adjusting csum_start when VLAN acceleration
is detected.

Fixes: 6680ec68eff4 ("tuntap: hardware vlan tx support")
Signed-off-by: Herbert Xu 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

Revert "drivers/net: Disable UFO through virtio"

2014-11-21T17:22:59+00:00

This reverts commit 2b52d6c6beda6308ba95024a1eba1dfc9515ba32 which was
commit 3d0ad09412ffe00c9afa201d01effdb6023d09b4 upstream.

Ben writes:

	Please drop this patch for 3.14 and 3.17.  It causes problems
	for migration of VMs and we're probably going to revert part of
	this.  The following patch ("drivers/net, ipv6: Select IPv6
	fragment idents for virtio UFO packets") might no longer apply,
	in which case you can drop that as well until we have this
	sorted out upstream.

Cc: Ben Hutchings 
Cc: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

drivers/net, ipv6: Select IPv6 fragment idents for virtio UFO packets

2014-11-14T16:59:44+00:00

[ Upstream commit 5188cd44c55db3e92cd9e77a40b5baa7ed4340f7 ]

UFO is now disabled on all drivers that work with virtio net headers,
but userland may try to send UFO/IPv6 packets anyway.  Instead of
sending with ID=0, we should select identifiers on their behalf (as we
used to).

Signed-off-by: Ben Hutchings 
Fixes: 916e4cf46d02 ("ipv6: reuse ip6_frag_id from ip6_ufo_append_data")
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

drivers/net: Disable UFO through virtio

2014-11-14T16:59:44+00:00

[ Upstream commit 3d0ad09412ffe00c9afa201d01effdb6023d09b4 ]

IPv6 does not allow fragmentation by routers, so there is no
fragmentation ID in the fixed header.  UFO for IPv6 requires the ID to
be passed separately, but there is no provision for this in the virtio
net protocol.

Until recently our software implementation of UFO/IPv6 generated a new
ID, but this was a bug.  Now we will use ID=0 for any UFO/IPv6 packet
passed through a tap, which is even worse.

Unfortunately there is no distinction between UFO/IPv4 and v6
features, so disable UFO on taps and virtio_net completely until we
have a proper solution.

We cannot depend on VM managers respecting the tap feature flags, so
keep accepting UFO packets but log a warning the first time we do
this.

Signed-off-by: Ben Hutchings 
Fixes: 916e4cf46d02 ("ipv6: reuse ip6_frag_id from ip6_ufo_append_data")
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tun: remove bogus hardware vlan acceleration flags from vlan_features

2014-02-20T07:15:38+00:00

Even though only the outer vlan tag can be HW accelerated in the transmission
path, in the TUN/TAP driver vlan_features mirrors hw_features, which happens
to have the NETIF_F_HW_VLAN_?TAG_TX flags set. Because of this, during packet
tranmisssion through a stacked vlan device dev_hard_start_xmit, (incorrectly)
assuming that the vlan device supports hardware vlan acceleration, does not
add the vlan header to the skb payload and the inner vlan tags are lost
(vlan_tci contains the outer vlan tag when userspace reads the packet from
the tap device).

Signed-off-by: Fernando Luis Vazquez Cao 
Signed-off-by: Toshiaki Makita 
Signed-off-by: David S. Miller

netdevice: add queue selection fallback handler for ndo_select_queue

2014-02-17T05:36:34+00:00

Add a new argument for ndo_select_queue() callback that passes a
fallback handler. This gets invoked through netdev_pick_tx();
fallback handler is currently __netdev_pick_tx() as most drivers
invoke this function within their customized implementation in
case for skbs that don't need any special handling. This fallback
handler can then be replaced on other call-sites with different
queue selection methods (e.g. in packet sockets, pktgen etc).

This also has the nice side-effect that __netdev_pick_tx() is
then only invoked from netdev_pick_tx() and export of that
function to modules can be undone.

Suggested-by: David S. Miller 
Signed-off-by: Daniel Borkmann 
Signed-off-by: David S. Miller

tun: add device name(iff) field to proc fdinfo entry

2014-01-29T07:46:56+00:00

A file descriptor opened for /dev/net/tun and a tun device are
connected with ioctl.  Though understanding the connection is
important for trouble shooting, no way is given to a user to know
the connected device for a given file descriptor at userland.

This patch adds a new fdinfo field for the device name connected to
a file descriptor opened for /dev/net/tun.

Here is an example of the field:

    # lsof | grep tun
    qemu-syst 4565         qemu   25u      CHR             10,200       0t138      12921 /dev/net/tun
    ...

    # cat /proc/4565/fdinfo/25
    pos:	138
    flags:	0104002
    iff:	vnet0

    # ip link show dev vnet0
    8: vnet0:  mtu 1500 ...

changelog:

    v2: indent iff just like the other fdinfo fields are.
    v3: remove unused variable.
        Both are suggested by David Miller .

Signed-off-by: Masatake YAMATO 
Signed-off-by: David S. Miller

tuntap: Fix for a race in accessing numqueues

2014-01-23T05:32:56+00:00

A patch for fixing a race between queue selection and changing queues
was introduced in commit 92bb73ea2("tuntap: fix a possible race between
queue selection and changing queues").

The fix was to prevent the driver from re-reading the tun->numqueues
more than once within tun_select_queue() using ACCESS_ONCE().

We have been experiancing 'Divide-by-zero' errors in tun_net_xmit()
since we moved from 3.6 to 3.10, and believe that they come from a
simular source where the value of tun->numqueues changes to zero
between the first and a subsequent read of tun->numqueues.

The fix is a simular use of ACCESS_ONCE(), as well as a multiply
instead of a divide in the if statement.

Signed-off-by: Dominic Curran 
Cc: Jason Wang 
Cc: Maxim Krasnyansky 
Acked-by: Jason Wang 
Acked-by: Max Krasnyansky 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2014-01-14T22:42:42+00:00

net: core: explicitly select a txq before doing l2 forwarding

2014-01-10T18:23:08+00:00

Currently, the tx queue were selected implicitly in ndo_dfwd_start_xmit(). The
will cause several issues:

- NETIF_F_LLTX were removed for macvlan, so txq lock were done for macvlan
  instead of lower device which misses the necessary txq synchronization for
  lower device such as txq stopping or frozen required by dev watchdog or
  control path.
- dev_hard_start_xmit() was called with NULL txq which bypasses the net device
  watchdog.
- dev_hard_start_xmit() does not check txq everywhere which will lead a crash
  when tso is disabled for lower device.

Fix this by explicitly introducing a new param for .ndo_select_queue() for just
selecting queues in the case of l2 forwarding offload. netdev_pick_tx() was also
extended to accept this parameter and dev_queue_xmit_accel() was used to do l2
forwarding transmission.

With this fixes, NETIF_F_LLTX could be preserved for macvlan and there's no need
to check txq against NULL in dev_hard_start_xmit(). Also there's no need to keep
a dedicated ndo_dfwd_start_xmit() and we can just reuse the code of
dev_queue_xmit() to do the transmission.

In the future, it was also required for macvtap l2 forwarding support since it
provides a necessary synchronization method.

Cc: John Fastabend 
Cc: Neil Horman 
Cc: e1000-devel@lists.sourceforge.net
Signed-off-by: Jason Wang 
Acked-by: Neil Horman 
Acked-by: John Fastabend 
Signed-off-by: David S. Miller