Unlike a normal socket path, the tuntap device send path does
not have any accounting.  This means that the user-space sender
may be able to pin down arbitrary amounts of kernel memory by
continuing to send data to an end-point that is congested.

Even when this isn't an issue because of limited queueing at
most end points, this can also be a problem because its only
response to congestion is packet loss.  That is, when those
local queues at the end-point fills up, the tuntap device will
start wasting system time because it will continue to send
data there which simply gets dropped straight away.

Of course one could argue that everybody should do congestion
control end-to-end, unfortunately there are people in this world
still hooked on UDP, and they don't appear to be going away
anywhere fast.  In fact, we've always helped them by performing
accounting in our UDP code, the sole purpose of which is to
provide congestion feedback other than through packet loss.

This patch attempts to apply the same bandaid to the tuntap device.
It creates a pseudo-socket object which is used to account our
packets just as a normal socket does for UDP.  Of course things
are a little complex because we're actually reinjecting traffic
back into the stack rather than out of the stack.

The stack complexities however should have been resolved by preceding
patches.  So this one can simply start using skb_set_owner_w.

For now the accounting is essentially disabled by default for
backwards compatibility.  In particular, we set the cap to INT_MAX.
This is so that existing applications don't get confused by the
sudden arrival EAGAIN errors.

In future we may wish (or be forced to) do this by default.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

The function sock_alloc_send_pskb is completely useless if not
exported since most of the code in it won't be used as is.  In
fact, this code has already been duplicated in the tun driver.

Now that we need accounting in the tun driver, we can in fact
use this function as is.  So this patch marks it for export again.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

As it currently stands, skb destructors are forbidden on the
receive path because the protocol end-points will overwrite
any existing destructor with their own.

This is the reason why we have to call skb_orphan in the loopback
driver before we reinject the packet back into the stack, thus
creating a period during which loopback traffic isn't charged
to any socket.

With virtualisation, we have a similar problem in that traffic
is reinjected into the stack without being associated with any
socket entity, thus providing no natural congestion push-back
for those poor folks still stuck with UDP.

Now had we been consistent in telling them that UDP simply has
no congestion feedback, I could just fob them off.  Unfortunately,
we appear to have gone to some length in catering for this on
the standard UDP path, with skb/socket accounting so that has
created a very unhealthy dependency.

Alas habits are difficult to break out of, so we may just have
to allow skb destructors on the receive path.

It turns out that making skb destructors useable on the receive path
isn't as easy as it seems.  For instance, simply adding skb_orphan
to skb_set_owner_r isn't enough.  This is because we assume all
over the IP stack that skb->sk is an IP socket if present.

The new transparent proxy code goes one step further and assumes
that skb->sk is the receiving socket if present.

Now all of this can be dealt with by adding simple checks such
as only treating skb->sk as an IP socket if skb->sk->sk_family
matches.  However, it turns out that for bridging at least we
don't need to do all of this work.

This is of interest because most virtualisation setups use bridging
so we don't actually go through the IP stack on the host (with
the exception of our old nemesis the bridge netfilter, but that's
easily taken care of).

So this patch simply adds skb_orphan to the point just before we
enter the IP stack, but after we've gone through the bridge on the
receive path.  It also adds an skb_orphan to the one place in
netfilter that touches skb->sk/skb->destructor, that is, tproxy.

One word of caution, because of the internal code structure, anyone
wishing to deploy this must use skb_set_owner_w as opposed to
skb_set_owner_r since many functions that create a new skb from
an existing one will invoke skb_set_owner_w on the new skb.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

Stashing is only supported on the 85xx (e500-based) SoCs.  The 83xx and 86xx
chips don't have a proper cache for this.  U-Boot has been updated to add
stashing properties to the device tree nodes of gianfar devices on 85xx.  So
now we modify Linux to keep stashing off unless those properties are there.
Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The MDIO bus drivers for the UCC and gianfar ethernet controllers are
essentially the same.  There's no reason to duplicate that much code.
Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

SOFT_RESET must be asserted for at least 3 TX clocks in order for it to work
properly.  The syncs in the gfar_write() commands have been hiding this, but
we need to guarantee it.
Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

BD_LENGTH_MASK is supposed to catch the low 16-bits of the status field, not
the low byte.  The old way, we would never be able to clean up tx packets with
sizes divisible by 256.
Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Many physical NICs let the OS re-program the "hardware" MAC
address.  Virtual NICs should allow this too.
Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Acked-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

VLAN filtering allows the hypervisor to drop packets from VLANs
that we're not a part of, further reducing the number of extraneous
packets recieved.  This makes use of the VLAN virtqueue command class.
The CTRL_VLAN feature bit tells us whether the backend supports VLAN
filtering.
Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

Make use of the MAC control virtqueue class to support a MAC
filter table.  The filter table is managed by the hypervisor.
We consider the table to be available if the CTRL_RX feature
bit is set.  We leave it to the hypervisor to manage the table
and enable promiscuous or all-multi mode as necessary depending
on the resources available to it.
Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

Make use of the RX_MODE control virtqueue class to enable the
set_rx_mode netdev interface.  This allows us to selectively
enable/disable promiscuous and allmulti mode so we don't see
packets we don't want.  For now, we automatically enable these
as needed if additional unicast or multicast addresses are
requested.
Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

This will be used for RX mode, MAC filter table, VLAN filtering, etc...

The control transaction consists of one or more "out" sg entries and
one or more "in" sg entries.  The first out entry contains a header
defining the class and command.  Additional out entries may provide
data for the command.  The last in entry provides a status response
back from the command.

Virtqueues typically run asynchronous, running a callback function
when there's data in the channel.  We can't readily make use of this
in the command paths where we need to use this.  Instead, we kick
the virtqueue and spin.  The kick causes an I/O write, triggering an
immediate trap into the hypervisor.
Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

The LRO switch is always set to 1 in the rx processing loop.
It breaks the accelerated iSCSI receive traffic.
Fix its computation.
Signed-off-by: Divy Le Ray <divy@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/blackfin-2.6: (40 commits)
  Blackfin arch: Remove outdated code
  Blackfin arch: Fix udelay implementation
  Blackfin arch: Update Copyright information
  Blackfin arch: Add BF561 PPI POLS, POLC Masks
  Blackfin arch: Update CM-BF527 kernel config
  Blackfin arch: define bfin_memmap as static since it is only used here
  Blackfin arch: cplb mananger: use a do...while loop rather than a for loop
  Blackfin arch: fix bug - traps test case 19 for exception 0x2d fails
  Blackfin arch: add platform device bfin_mii-bus and KSZ8893M switch driver platform resources to board files
  Blackfin arch: build jtag tty driver as a module by default
  Blackfin arch: fix 2 bugs related to debug
  Blackfin arch: Add ANOMALY_05000380 to BF54x to kill the compile warning
  Blackfin arch: Fix bug - 561 SMP kernel can't boot from jffs2
  Blackfin arch: base SIC_IWR# programming on whether the MMR exists
  Blackfin arch: read SYSCR on newer parts that mirror the bits of SWRST in it
  Blackfin arch: fixup board init function name
  Blackfin arch: drop CONFIG_I2C_BOARDINFO ifdefs
  Blackfin arch: bfin_reset->_bfin_reset redirection no longer needed
  Blackfin arch: sync reboot handler with version in u-boot
  Blackfin arch: Faster Implementation of csum_tcpudp_nofold()
  ...

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6:
  sparc64: Kill bogus TPC/address truncation during 32-bit faults.
  sparc: fixup for sparseirq changes
  sparc64: Validate kernel generated fault addresses on sparc64.
  sparc64: On non-Niagara, need to touch NMI watchdog in NOHZ mode.
  sparc64: Implement NMI watchdog on capable cpus.
  sparc: Probe PMU type and record in sparc_pmu_type.
  sparc64: Move generic PCR support code to seperate file.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
  sunrpc: fix rdma dependencies
  e1000: Fix PCI enable to honor the need_ioport flag
  sgi-xp: link XPNET's net_device_ops to its net_device structure
  pcnet_cs: Fix misuse of the equality operator.
  hso: add new device id's
  dca: redesign locks to fix deadlocks
  cassini/sungem: limit reaches -1, but 0 tested
  net: variables reach -1, but 0 tested
  qlge: bugfix: Add missing netif_napi_del call.
  qlge: bugfix: Add flash offset for second port.
  qlge: bugfix: Fix endian issue when reading flash.
  udp: increments sk_drops in __udp_queue_rcv_skb()
  net: Fix userland breakage wrt. linux/if_tunnel.h
  net: packet socket packet_lookup_frame fix

* 'for-linus' of git://git.o-hand.com/linux-mfd:
  mfd: Remove non exported references from pcf50633

The removed version with the loop registers saved on the stack was
originally intended to workaround the missing toolchain support for
LoopReg Clobbers.

Since our toolchain now supports these there is no point in keeping this
workaround. And since we don't touch LoopRegs anymore we're no longer
subject for ANOMALY_05000312.
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

Avoid possible overflow during 32*32->32 multiplies.
Reported-by: Marco Reppenhagen <marco.reppenhagen@auerswald.de>
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

use a do...while loop rather than a for loop to get slightly better
optimization and to avoid gcc "may be used uninitialized" warnings ...
we know that the [id]cplb_nr_bounds variables will never be 0, so this
is OK
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

Enable null pointer checking for ICPLBs. The code was there but for
some reason I had commented it out at some stage during development.

Should restrict this to 1K since atomic ops start there.
Signed-off-by: Bernd Schmidt <bernds_cb1@t-online.de>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

Blackfin arch: add platform device bfin_mii-bus and KSZ8893M switch driver platform resources to board files
Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

 - unable to single step over emuexcpt instruction
 - gdbproxy goes into infinite loop when doing gdb does "next" over
   "emuexcpt"

Don't decrement PC after software breakpoint.
Signed-off-by: Jie Zhang <jie.zhang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

Signed-off-by: Bryan Wu <cooloney@kernel.org>

bss_l2 section is garbage when the data in this section is used by
_bfin_relocate_l1_mem, so move the zero out function ahead.
Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

base SIC_IWR# programming on whether the MMR exists
rather than having to maintain another list of processors
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

Drop CONFIG_I2C_BOARDINFO ifdefs as the common i2c header handles this
already by stubbing things out
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

Avoid conditional branch instructions during carry bit additions.
Special thanks to Bernd.
Simplify: Use ((len + proto) << 8) like every other __LITTLE_ENDIAN__ machine

Cc: Bernd Schmidt <bernds_cb1@t-online.de>
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>