The BPF verifier conflict was some minor contextual issue.
The TUN conflict was less trivial. Cong Wang fixed a memory leak of
tfile->tx_array in 'net'. This is an skb_array. But meanwhile in
net-next tun changed tfile->tx_arry into tfile->tx_ring which is a
ptr_ring.
Signed-off-by: David S. Miller <davem@davemloft.net>
syzbot reported yet another crash [1] that is caused by
insufficient validation of DODGY packets.
Two bugs are happening here to trigger the crash.
1) Flow dissection leaves with incorrect thoff field.
2) skb_probe_transport_header() sets transport header to this invalid
thoff, even if pointing after skb valid data.
3) qdisc_pkt_len_init() reads out-of-bound data because it
trusts tcp_hdrlen(skb)
Possible fixes :
- Full flow dissector validation before injecting bad DODGY packets in
the stack.
This approach was attempted here : https://patchwork.ozlabs.org/patch/
861874/
- Have more robust functions in the core.
This might be needed anyway for stable versions.
This patch fixes the flow dissection issue.
[1]
CPU: 1 PID: 3144 Comm: syzkaller271204 Not tainted 4.15.0-rc4-mm1+ #49
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x194/0x257 lib/dump_stack.c:53
print_address_description+0x73/0x250 mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:355 [inline]
kasan_report+0x23b/0x360 mm/kasan/report.c:413
__asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:432
__tcp_hdrlen include/linux/tcp.h:35 [inline]
tcp_hdrlen include/linux/tcp.h:40 [inline]
qdisc_pkt_len_init net/core/dev.c:3160 [inline]
__dev_queue_xmit+0x20d3/0x2200 net/core/dev.c:3465
dev_queue_xmit+0x17/0x20 net/core/dev.c:3554
packet_snd net/packet/af_packet.c:2943 [inline]
packet_sendmsg+0x3ad5/0x60a0 net/packet/af_packet.c:2968
sock_sendmsg_nosec net/socket.c:628 [inline]
sock_sendmsg+0xca/0x110 net/socket.c:638
sock_write_iter+0x31a/0x5d0 net/socket.c:907
call_write_iter include/linux/fs.h:1776 [inline]
new_sync_write fs/read_write.c:469 [inline]
__vfs_write+0x684/0x970 fs/read_write.c:482
vfs_write+0x189/0x510 fs/read_write.c:544
SYSC_write fs/read_write.c:589 [inline]
SyS_write+0xef/0x220 fs/read_write.c:581
entry_SYSCALL_64_fastpath+0x1f/0x96
Fixes: 34fad54c25 ("net: __skb_flow_dissect() must cap its return value")
Fixes: a6e544b0a8 ("flow_dissector: Jump to exit code in __skb_flow_dissect")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The batman-adv unicast packets contain a full layer 2 frame in encapsulated
form. The flow dissector must therefore be able to parse the batman-adv
unicast header to reach the layer 2+3 information.
+--------------------+
| ip(v6)hdr |
+--------------------+
| inner ethhdr |
+--------------------+
| batadv unicast hdr |
+--------------------+
| outer ethhdr |
+--------------------+
The obtained information from the upper layer can then be used by RPS to
schedule the processing on separate cores. This allows better distribution
of multiple flows from the same neighbor to different cores.
Signed-off-by: Sven Eckelmann <sven.eckelmann@openmesh.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move dissection of tunnel info to outside of the main flow dissection
function, __skb_flow_dissect(). The sole user of this feature, the flower
classifier, is updated to call tunnel info dissection directly, using
skb_flow_dissect_tunnel_info().
This results in a slightly less complex implementation of
__skb_flow_dissect(), in particular removing logic from that call path
which is not used by the majority of users. The expense of this is borne by
the flower classifier which now has to make an extra call for tunnel info
dissection.
This patch should not result in any behavioural change.
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, the TIPC RPS dissector is based only on the incoming packets'
source node address, hence steering all traffic from a node to the same
core. We have seen that this makes the links vulnerable to starvation
and unnecessary resets when we turn down the link tolerance to very low
values.
To reduce the risk of this happening, we exempt probe and probe replies
packets from the convergence to one core per source node. Instead, we do
the opposite, - we try to diverge those packets across as many cores as
possible, by randomizing the flow selector key.
To make such packets identifiable to the dissector, we add a new
'is_keepalive' bit to word 0 of the LINK_PROTOCOL header. This bit is
set both for PROBE and PROBE_REPLY messages, and only for those.
It should be noted that these packets are not part of any flow anyway,
and only constitute a minuscule fraction of all packets sent across a
link. Hence, there is no risk that this will affect overall performance.
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move dissection of tunnel info from the flower classifier to the flow
dissector where all other dissection occurs. This should not have any
behavioural affect on other users of the flow dissector.
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In flow dissector there are no limits to the number of nested
encapsulations or headers that might be dissected which makes for a
nice DOS attack. This patch sets a limit of the number of headers
that flow dissector will parse.
Headers includes network layer headers, transport layer headers, shim
headers for encapsulation, IPv6 extension headers, etc. The limit for
maximum number of headers to parse has be set to fifteen to account for
a reasonable number of encapsulations, extension headers, VLAN,
in a packet. Note that this limit does not supercede the STOP_AT_*
flags which may stop processing before the headers limit is reached.
Reported-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
__skb_flow_dissect is riddled with gotos that make discerning the flow,
debugging, and extending the capability difficult. This patch
reorganizes things so that we only perform goto's after the two main
switch statements (no gotos within the cases now). It also eliminates
several goto labels so that there are only two labels that can be target
for goto.
Reported-by: Alexander Popov <alex.popov@linux.com>
Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
The following error was introduced by
commit 43e665287f ("net-next: dsa: fix flow dissection")
due to a missing #if guard
net/core/flow_dissector.c: In function '__skb_flow_dissect':
net/core/flow_dissector.c:448:18: error: 'struct net_device' has no member named 'dsa_ptr'
ops = skb->dev->dsa_ptr->tag_ops;
^
make[3]: *** [net/core/flow_dissector.o] Error 1
Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
RPS and probably other kernel features are currently broken on some if not
all DSA devices. The root cause of this is that skb_hash will call the
flow_dissector. At this point the skb still contains the magic switch
header and the skb->protocol field is not set up to the correct 802.3
value yet. By the time the tag specific code is called, removing the header
and properly setting the protocol an invalid hash is already set. In the
case of the mt7530 this will result in all flows always having the same
hash.
Signed-off-by: Muciri Gatimu <muciri@openmesh.com>
Signed-off-by: Shashidhar Lakkavalli <shashidhar.lakkavalli@openmesh.com>
Signed-off-by: John Crispin <john@phrozen.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
They are introduced by commit f70ea018da
("net: Add functions to get skb->hash based on flow structures")
but never gets used in tree.
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for dissection of ip tos and ttl and ipv6 traffic-class
and hoplimit. Both are dissected into the same struct.
Uses similar call to ip dissection function as with tcp, arp and others.
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for dissection of tcp flags. Uses similar function call to
tcp dissection function as arp, mpls and others.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for parsing MPLS flows to the flow dissector in preparation for
adding MPLS match support to cls_flower.
Signed-off-by: Benjamin LaHaise <benjamin.lahaise@netronome.com>
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Simon Horman <simon.horman@netronome.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jiri Pirko <jiri@mellanox.com>
Cc: Eric Dumazet <jhs@mojatatu.com>
Cc: Hadar Hen Zion <hadarh@mellanox.com>
Cc: Gao Feng <fgao@ikuai8.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Mostly simple cases of overlapping changes (adding code nearby,
a function whose name changes, for example).
Signed-off-by: David S. Miller <davem@davemloft.net>
The last argument to __skb_header_pointer() should be a buffer large
enough to store struct arphdr. This can be a pointer to a struct arphdr
structure. The code was previously using a pointer to a pointer to
struct arphdr.
By my counting the storage available both before and after is 8 bytes on
x86_64.
Fixes: 55733350e5 ("flow disector: ARP support")
Reported-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make the main flow_dissect function a bit smaller and move the GRE
dissection into a separate function.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Align with "ip_proto_again" label used in the same function and rename
vague "again" to "proto_again".
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now, when an unexpected element in the GRE header appears, we break so
the l4 ports are processed. But since the ports are processed
unconditionally, there will be certainly random values dissected. Fix
this by just bailing out in such situations.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make the main flow_dissect function a bit smaller and move the MPLS
dissection into a separate function. Along with that, do the MPLS header
processing only in case the flow dissection user requires it.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make the main flow_dissect function a bit smaller and move the ARP
dissection into a separate function. Along with that, do the ARP header
processing only in case the flow dissection user requires it.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
arp is being checked instead of arp_eth to see if the call to
__skb_header_pointer failed. Fix this by checking arp_eth is
null instead of arp. Also fix to use length hlen rather than
hlen - sizeof(_arp); thanks to Eric Dumazet for spotting
this latter issue.
CoverityScan CID#1396428 ("Logically dead code") on 2nd
arp comparison (which should be arp_eth instead).
Fixes: commit 55733350e5 ("flow disector: ARP support")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Allow dissection of (R)ARP operation hardware and protocol addresses
for Ethernet hardware and IPv4 protocol addresses.
There are currently no users of FLOW_DISSECTOR_KEY_ARP.
A follow-up patch will allow FLOW_DISSECTOR_KEY_ARP to be used by the
flower classifier.
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Removes following sparse complain :
net/core/flow_dissector.c:70:8: warning: symbol 'skb_flow_get_be16'
was not declared. Should it be static?
Fixes: 972d3876fa ("flow dissector: ICMP support")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Allow dissection of ICMP(V6) type and code. This should only occur
if a packet is ICMP(V6) and the dissector has FLOW_DISSECTOR_KEY_ICMP set.
There are currently no users of FLOW_DISSECTOR_KEY_ICMP.
A follow-up patch will allow FLOW_DISSECTOR_KEY_ICMP to be used by
the flower classifier.
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
udplite conflict is resolved by taking what 'net-next' did
which removed the backlog receive method assignment, since
it is no longer necessary.
Two entries were added to the non-priv ethtool operations
switch statement, one in 'net' and one in 'net-next, so
simple overlapping changes.
Signed-off-by: David S. Miller <davem@davemloft.net>
Andre Noll reported panics after my recent fix (commit 34fad54c25
"net: __skb_flow_dissect() must cap its return value")
After some more headaches, Alexander root caused the problem to
init_default_flow_dissectors() being called too late, in case
a network driver like IGB is not a module and receives DHCP message
very early.
Fix is to call init_default_flow_dissectors() much earlier,
as it is a core infrastructure and does not depend on another
kernel service.
Fixes: 06635a35d1 ("flow_dissect: use programable dissector in skb_flow_dissect and friends")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Andre Noll <maan@tuebingen.mpg.de>
Diagnosed-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After Tom patch, thoff field could point past the end of the buffer,
this could fool some callers.
If an skb was provided, skb->len should be the upper limit.
If not, hlen is supposed to be the upper limit.
Fixes: a6e544b0a8 ("flow_dissector: Jump to exit code in __skb_flow_dissect")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Yibin Yang <yibyang@cisco.com
Acked-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Mostly simple overlapping changes.
For example, David Ahern's adjacency list revamp in 'net-next'
conflicted with an adjacency list traversal bug fix in 'net'.
Signed-off-by: David S. Miller <davem@davemloft.net>
gcc warns about an uninitialized pointer dereference in the vlan
priority handling:
net/core/flow_dissector.c: In function '__skb_flow_dissect':
net/core/flow_dissector.c:281:61: error: 'vlan' may be used uninitialized in this function [-Werror=maybe-uninitialized]
As pointed out by Jiri Pirko, the variable is never actually used
without being initialized first as the only way it end up uninitialized
is with skb_vlan_tag_present(skb)==true, and that means it does not
get accessed.
However, the warning hints at some related issues that I'm addressing
here:
- the second check for the vlan tag is different from the first one
that tests the skb for being NULL first, causing both the warning
and a possible NULL pointer dereference that was not entirely fixed.
- The same patch that introduced the NULL pointer check dropped an
earlier optimization that skipped the repeated check of the
protocol type
- The local '_vlan' variable is referenced through the 'vlan' pointer
but the variable has gone out of scope by the time that it is
accessed, causing undefined behavior
Caching the result of the 'skb && skb_vlan_tag_present(skb)' check
in a local variable allows the compiler to further optimize the
later check. With those changes, the warning also disappears.
Fixes: 3805a938a6 ("flow_dissector: Check skb for VLAN only if skb specified.")
Fixes: d5709f7ab7 ("flow_dissector: For stripped vlan, get vlan info from skb->vlan_tci")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Eric Garver <e@erig.me>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fixes a panic when calling eth_get_headlen(). Noticed on i40e driver.
Fixes: d5709f7ab7 ("flow_dissector: For stripped vlan, get vlan info from skb->vlan_tci")
Signed-off-by: Eric Garver <e@erig.me>
Reviewed-by: Jakub Sitnicki <jkbs@redhat.com>
Acked-by: Amir Vadai <amir@vadai.me>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conflicts:
drivers/net/ethernet/mediatek/mtk_eth_soc.c
drivers/net/ethernet/qlogic/qed/qed_dcbx.c
drivers/net/phy/Kconfig
All conflicts were cases of overlapping commits.
Signed-off-by: David S. Miller <davem@davemloft.net>
The original codes depend on that the function parameters are evaluated from
left to right. But the parameter's evaluation order is not defined in C
standard actually.
When flow_keys_have_l4(&keys) is invoked before ___skb_get_hash(skb, &keys,
hashrnd) with some compilers or environment, the keys passed to
flow_keys_have_l4 is not initialized.
Fixes: 6db61d79c1 ("flow_dissector: Ignore flow dissector return value from ___skb_get_hash")
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add vlan priority check to the flow dissector by adding new flow
dissector struct, flow_dissector_key_vlan which includes vlan tag
fields.
vlan_id and flow_label fields were under the same struct
(flow_dissector_key_tags). It was a convenient setting since struct
flow_dissector_key_tags is used by struct flow_keys and by setting
vlan_id and flow_label under the same struct, we get precisely 24 or 48
bytes in flow_keys from flow_dissector_key_basic.
Now, when adding vlan priority support, the code will be cleaner if
flow_label and vlan tag won't be under the same struct anymore.
Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Early in the datapath skb_vlan_untag function is called, stripped
the vlan from the skb and set skb->vlan_tci and skb->vlan_proto fields.
The current dissection doesn't handle stripped vlan packets correctly.
In some flows, vlan doesn't exist in skb->data anymore when applying
flow dissection on the skb, fix that.
In case vlan info wasn't stripped before applying flow_dissector (RPS
flow for example), or in case of skb with multiple vlans (e.g. 802.1ad),
get the vlan info from skb->data. The flow_dissector correctly skips
any number of vlans and stores only the first level vlan.
Fixes: 0744dd00c1 ('net: introduce skb_flow_dissect()')
Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The PPTP is encapsulated by GRE header with that GRE_VERSION bits
must contain one. But current GRE RPS needs the GRE_VERSION must be
zero. So RPS does not work for PPTP traffic.
In my test environment, there are four MIPS cores, and all traffic
are passed through by PPTP. As a result, only one core is 100% busy
while other three cores are very idle. After this patch, the usage
of four cores are balanced well.
Signed-off-by: Gao Feng <fgao@ikuai8.com>
Reviewed-by: Philip Prindeville <philipp@redfish-solutions.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
People who use PACKET_FANOUT_HASH want a symmetric hash, meaning that
they want packets going in both directions on a flow to hash to the
same bucket.
The core kernel SKB hash became non-symmetric when the ipv6 flow label
and other entities were incorporated into the standard flow hash order
to increase entropy.
But there are no users of PACKET_FANOUT_HASH who want an assymetric
hash, they all want a symmetric one.
Therefore, use the flow dissector to compute a flat symmetric hash
over only the protocol, addresses and ports. This hash does not get
installed into and override the normal skb hash, so this change has
no effect whatsoever on the rest of the stack.
Reported-by: Eric Leblond <eric@regit.org>
Tested-by: Eric Leblond <eric@regit.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Will be used in a following patch to query if a key is being used, and
what it's value in the target object.
Acked-by: John Fastabend <john.r.fastabend@intel.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Amir Vadai <amir@vadai.me>
Signed-off-by: David S. Miller <davem@davemloft.net>
The IPv6 parsing was using a local pointer when it could use the same
pointer as the IPv4 portion of the code since the key_addrs can support
both IPv4 and IPv6 as it is just a pointer.
Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Acked-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The flow dissector bits handling FCoE didn't bother to actually validate
that the space there was enough for the FCoE header. So we need to update
things so that if there is room we add the header and report a good result,
otherwise we do not add the header, and report the bad result.
Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Acked-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It turns out that for IPv4 we were reporting the ip_proto of the fragment,
and for IPv6 we were not. This patch updates that behavior so that we
always report the IP protocol of the fragment. In addition it takes the
steps of updating the payload offset code so that we will determine the
start of the payload not including the L4 header for any fragment after the
first.
Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Acked-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch corrects the logic for the IPv4 parsing so that it is consistent
with how we handle IPv6. Specifically if we do not have the flow key
indicating we want the addresses we still may need to take a look at the IP
fragmentation bits and to see if we should stop after we have recognized
the L3 header.
Fixes: 807e165dc4 ("flow_dissector: Add control/reporting of fragmentation")
Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Acked-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch corrects the unaligned accesses seen on GRE TEB tunnels when
generating hash keys. Specifically what this patch does is make it so that
we force the use of skb_copy_bits when the GRE inner headers will be
unaligned due to NET_IP_ALIGNED being a non-zero value.
Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Acked-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch fixes an issue with unaligned accesses when using
eth_get_headlen on a page that was DMA aligned instead of being IP aligned.
The fact is when trying to check the length we don't need to be looking at
the flow label so we can reorder the checks to first check if we are
supposed to gather the flow label and then make the call to actually get
it.
v2: Updated path so that either STOP_AT_FLOW_LABEL or KEY_FLOW_LABEL can
cause us to check for the flow label.
Reported-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
