linux-toradex.git/include/linux/skbuff.h, branch v3.14.24

net: Always untag vlan-tagged traffic on input.

2014-10-15T06:36:40+00:00

[ Upstream commit 0d5501c1c828fb97d02af50aa9d2b1a5498b94e4 ]

Currently the functionality to untag traffic on input resides
as part of the vlan module and is build only when VLAN support
is enabled in the kernel.  When VLAN is disabled, the function
vlan_untag() turns into a stub and doesn't really untag the
packets.  This seems to create an interesting interaction
between VMs supporting checksum offloading and some network drivers.

There are some drivers that do not allow the user to change
tx-vlan-offload feature of the driver.  These drivers also seem
to assume that any VLAN-tagged traffic they transmit will
have the vlan information in the vlan_tci and not in the vlan
header already in the skb.  When transmitting skbs that already
have tagged data with partial checksum set, the checksum doesn't
appear to be updated correctly by the card thus resulting in a
failure to establish TCP connections.

The following is a packet trace taken on the receiver where a
sender is a VM with a VLAN configued.  The host VM is running on
doest not have VLAN support and the outging interface on the
host is tg3:
10:12:43.503055 52:54:00:ae:42:3f > 28:d2:44:7d:c2:de, ethertype 802.1Q
(0x8100), length 78: vlan 100, p 0, ethertype IPv4, (tos 0x0, ttl 64, id 27243,
offset 0, flags [DF], proto TCP (6), length 60)
    10.0.100.1.58545 > 10.0.100.10.ircu-2: Flags [S], cksum 0xdc39 (incorrect
-> 0x48d9), seq 1069378582, win 29200, options [mss 1460,sackOK,TS val
4294837885 ecr 0,nop,wscale 7], length 0
10:12:44.505556 52:54:00:ae:42:3f > 28:d2:44:7d:c2:de, ethertype 802.1Q
(0x8100), length 78: vlan 100, p 0, ethertype IPv4, (tos 0x0, ttl 64, id 27244,
offset 0, flags [DF], proto TCP (6), length 60)
    10.0.100.1.58545 > 10.0.100.10.ircu-2: Flags [S], cksum 0xdc39 (incorrect
-> 0x44ee), seq 1069378582, win 29200, options [mss 1460,sackOK,TS val
4294838888 ecr 0,nop,wscale 7], length 0

This connection finally times out.

I've only access to the TG3 hardware in this configuration thus have
only tested this with TG3 driver.  There are a lot of other drivers
that do not permit user changes to vlan acceleration features, and
I don't know if they all suffere from a similar issue.

The patch attempt to fix this another way.  It moves the vlan header
stipping code out of the vlan module and always builds it into the
kernel network core.  This way, even if vlan is not supported on
a virtualizatoin host, the virtual machines running on top of such
host will still work with VLANs enabled.

CC: Patrick McHardy 
CC: Nithin Nayak Sujir 
CC: Michael Chan 
CC: Jiri Pirko 
Signed-off-by: Vladislav Yasevich 
Acked-by: Jiri Pirko 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

core, nfqueue, openvswitch: Orphan frags in skb_zerocopy and handle errors

2014-03-27T19:29:38+00:00

skb_zerocopy can copy elements of the frags array between skbs, but it doesn't
orphan them. Also, it doesn't handle errors, so this patch takes care of that
as well, and modify the callers accordingly. skb_tx_error() is also added to
the callers so they will signal the failed delivery towards the creator of the
skb.

Signed-off-by: Zoltan Kiss 
Signed-off-by: David S. Miller

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf

2014-02-19T18:12:53+00:00

Pablo Neira Ayuso says:

====================
Netfilter fixes for net

The following patchset contains Netfilter fixes for your net tree,
they are:

* Fix nf_trace in nftables if XT_TRACE=n, from Florian Westphal.

* Don't use the fast payload operation in nf_tables if the length is
  not power of 2 or it is not aligned, from Nikolay Aleksandrov.

* Fix missing break statement the inet flavour of nft_reject, which
  results in evaluating IPv4 packets with the IPv6 evaluation routine,
  from Patrick McHardy.

* Fix wrong kconfig symbol in nft_meta to match the routing realm,
  from Paul Bolle.

* Allocate the NAT null binding when creating new conntracks via
  ctnetlink to avoid that several packets race at initializing the
  the conntrack NAT extension, original patch from Florian Westphal,
  revisited version from me.

* Fix DNAT handling in the snmp NAT helper, the same handling was being
  done for SNAT and DNAT and 2.4 already contains that fix, from
  Francois-Xavier Le Bail.
====================

Signed-off-by: David S. Miller

netfilter: nf_tables: fix nf_trace always-on with XT_TRACE=n

2014-02-17T10:20:12+00:00

When using nftables with CONFIG_NETFILTER_XT_TARGET_TRACE=n, we get
lots of "TRACE: filter:output:policy:1 IN=..." warnings as several
places will leave skb->nf_trace uninitialised.

Unlike iptables tracing functionality is not conditional in nftables,
so always copy/zero nf_trace setting when nftables is enabled.

Move this into __nf_copy() helper.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

net: ip, ipv6: handle gso skbs in forwarding path

2014-02-13T22:17:02+00:00

Marcelo Ricardo Leitner reported problems when the forwarding link path
has a lower mtu than the incoming one if the inbound interface supports GRO.

Given:
Host  R1  R2

Host sends tcp stream which is routed via R1 and R2.  R1 performs GRO.

In this case, the kernel will fail to send ICMP fragmentation needed
messages (or pkt too big for ipv6), as GSO packets currently bypass dstmtu
checks in forward path. Instead, Linux tries to send out packets exceeding
the mtu.

When locking route MTU on Host (i.e., no ipv4 DF bit set), R1 does
not fragment the packets when forwarding, and again tries to send out
packets exceeding R1-R2 link mtu.

This alters the forwarding dstmtu checks to take the individual gso
segment lengths into account.

For ipv6, we send out pkt too big error for gso if the individual
segments are too big.

For ipv4, we either send icmp fragmentation needed, or, if the DF bit
is not set, perform software segmentation and let the output path
create fragments when the packet is leaving the machine.
It is not 100% correct as the error message will contain the headers of
the GRO skb instead of the original/segmented one, but it seems to
work fine in my (limited) tests.

Eric Dumazet suggested to simply shrink mss via ->gso_size to avoid
sofware segmentation.

However it turns out that skb_segment() assumes skb nr_frags is related
to mss size so we would BUG there.  I don't want to mess with it considering
Herbert and Eric disagree on what the correct behavior should be.

Hannes Frederic Sowa notes that when we would shrink gso_size
skb_segment would then also need to deal with the case where
SKB_MAX_FRAGS would be exceeded.

This uses sofware segmentation in the forward path when we hit ipv4
non-DF packets and the outgoing link mtu is too small.  Its not perfect,
but given the lack of bug reports wrt. GRO fwd being broken this is a
rare case anyway.  Also its not like this could not be improved later
once the dust settles.

Acked-by: Herbert Xu 
Reported-by: Marcelo Ricardo Leitner 
Signed-off-by: Florian Westphal 
Signed-off-by: David S. Miller

net: add and use skb_gso_transport_seglen()

2014-01-27T06:38:23+00:00

This moves part of Eric Dumazets skb_gso_seglen helper from tbf sched to
skbuff core so it may be reused by upcoming ip forwarding path patch.

Signed-off-by: Florian Westphal 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: Add skb_get_hash_raw

2014-01-17T00:22:54+00:00

Function to just return skb->rxhash without checking to see if it needs
to be recomputed.

Signed-off-by: Tom Herbert 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: add skb_checksum_setup

2014-01-14T22:24:19+00:00

This patch adds a function to set up the partial checksum offset for IP
packets (and optionally re-calculate the pseudo-header checksum) into the
core network code.
The implementation was previously private and duplicated between xen-netback
and xen-netfront, however it is not xen-specific and is potentially useful
to any network driver.

Signed-off-by: Paul Durrant 
Cc: David Miller 
Cc: Eric Dumazet 
Cc: Veaceslav Falico 
Cc: Alexander Duyck 
Cc: Nicolas Dichtel 
Signed-off-by: David S. Miller

net: skbuff: const-ify casts in skb_queue_* functions

2014-01-07T23:34:00+00:00

We should const-ify comparisons on skb_queue_* inline helper
functions as their parameters are const as well, so lets not
drop that.

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

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/jesse/openvswitch

2014-01-07T00:48:38+00:00

Jesse Gross says:

====================
[GIT net-next] Open vSwitch

Open vSwitch changes for net-next/3.14. Highlights are:
 * Performance improvements in the mechanism to get packets to userspace
   using memory mapped netlink and skb zero copy where appropriate.
 * Per-cpu flow stats in situations where flows are likely to be shared
   across CPUs. Standard flow stats are used in other situations to save
   memory and allocation time.
 * A handful of code cleanups and rationalization.
====================

Signed-off-by: David S. Miller