Several of the GRE functions defined in net/ipv4/ip_gre.c are usable
for IPv6 GRE implementation (that is they are protocol agnostic).
These include:
- GRE flag handling functions are move to gre.h
- GRE build_header is moved to gre.h and renamed gre_build_header
- parse_gre_header is moved to gre_demux.c and renamed gre_parse_header
- iptunnel_pull_header is taken out of gre_parse_header. This is now
done by caller. The header length is returned from gre_parse_header
in an int* argument.
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Some basic changes to make IPv6 tunnel receive path look more like
IPv4 path:
- Make ip6_tnl_rcv non-static so that GREv6 and others can call it
- Make ip6_tnl_rcv look like ip_tunnel_rcv
- Switch to gro_cells_receive
- Make ip6_tnl_rcv non-static and export it
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Large sendmsg()/write() hold socket lock for the duration of the call,
unless sk->sk_sndbuf limit is hit. This is bad because incoming packets
are parked into socket backlog for a long time.
Critical decisions like fast retransmit might be delayed.
Receivers have to maintain a big out of order queue with additional cpu
overhead, and also possible stalls in TX once windows are full.
Bidirectional flows are particularly hurt since the backlog can become
quite big if the copy from user space triggers IO (page faults)
Some applications learnt to use sendmsg() (or sendmmsg()) with small
chunks to avoid this issue.
Kernel should know better, right ?
Add a generic sk_flush_backlog() helper and use it right
before a new skb is allocated. Typically we put 64KB of payload
per skb (unless MSG_EOR is requested) and checking socket backlog
every 64KB gives good results.
As a matter of fact, tests with TSO/GSO disabled give very nice
results, as we manage to keep a small write queue and smaller
perceived rtt.
Note that sk_flush_backlog() maintains socket ownership,
so is not equivalent to a {release_sock(sk); lock_sock(sk);},
to ensure implicit atomicity rules that sendmsg() was
giving to (possibly buggy) applications.
In this simple implementation, I chose to not call tcp_release_cb(),
but we might consider this later.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Socket backlog processing is a major latency source.
With current TCP socket sk_rcvbuf limits, I have sampled __release_sock()
holding cpu for more than 5 ms, and packets being dropped by the NIC
once ring buffer is filled.
All users are now ready to be called from process context,
we can unblock BH and let interrupts be serviced faster.
cond_resched_softirq() could be removed, as it has no more user.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
sctp_inq_push() will soon be called without BH being blocked
when generic socket code flushes the socket backlog.
It is very possible SCTP can be converted to not rely on BH,
but this needs to be done by SCTP experts.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
UDP uses the generic socket backlog code, and this will soon
be changed to not disable BH when protocol is called back.
We need to use appropriate SNMP accessors.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
DCCP uses the generic backlog code, and this will soon
be changed to not disable BH when protocol is called back.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
AFAIK, nothing in current TCP stack absolutely wants BH
being disabled once socket is owned by a thread running in
process context.
As mentioned in my prior patch ("tcp: give prequeue mode some care"),
processing a batch of packets might take time, better not block BH
at all.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
We want to to make TCP stack preemptible, as draining prequeue
and backlog queues can take lot of time.
Many SNMP updates were assuming that BH (and preemption) was disabled.
Need to convert some __NET_INC_STATS() calls to NET_INC_STATS()
and some __TCP_INC_STATS() to TCP_INC_STATS()
Before using this_cpu_ptr(net->ipv4.tcp_sk) in tcp_v4_send_reset()
and tcp_v4_send_ack(), we add an explicit preempt disabled section.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Dave Miller pointed out that fb586f25300f ("sctp: delay calls to
sk_data_ready() as much as possible") may insert latency specially if
the receiving application is running on another CPU and that it would be
better if we signalled as early as possible.
This patch thus basically inverts the logic on fb586f25300f and signals
it as early as possible, similar to what we had before.
Fixes: fb586f25300f ("sctp: delay calls to sk_data_ready() as much as possible")
Reported-by: Dave Miller <davem@davemloft.net>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When we are displaying statistics for the first link established between
two peers, it will always be presented as STANDBY although it in reality
is ACTIVE.
This happens because we forget to set the 'active' flag in the link
instance at the moment it is established. Although this is a bug, it only
has impact on the presentation view of the link, not on its actual
functionality.
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
is_skb_forwardable is not supposed to change anything so constify its
arguments
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch overloads the DSA master netdev, aka CPU Ethernet MAC to also
include switch-side statistics, which is useful for debugging purposes,
when the switch is not properly connected to the Ethernet MAC (duplex
mismatch, (RG)MII electrical issues etc.).
We accomplish this by retaining the original copy of the master netdev's
ethtool_ops, and just overload the 3 operations we care about:
get_sset_count, get_strings and get_ethtool_stats so as to intercept
these calls and call into the original master_netdev ethtool_ops, plus
our own.
We take this approach as opposed to providing a set of DSA helper
functions that would retrive the CPU port's statistics, because the
entire purpose of DSA is to allow unmodified Ethernet MAC drivers to be
used as CPU conduit interfaces, therefore, statistics overlay in such
drivers would simply not scale.
The new ethtool -S <iface> output would therefore look like this now:
<iface> statistics
p<2 digits cpu port number>_<switch MIB counter names>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
TCP prequeue goal is to defer processing of incoming packets
to user space thread currently blocked in a recvmsg() system call.
Intent is to spend less time processing these packets on behalf
of softirq handler, as softirq handler is unfair to normal process
scheduler decisions, as it might interrupt threads that do not
even use networking.
Current prequeue implementation has following issues :
1) It only checks size of the prequeue against sk_rcvbuf
It was fine 15 years ago when sk_rcvbuf was in the 64KB vicinity.
But we now have ~8MB values to cope with modern networking needs.
We have to add sk_rmem_alloc in the equation, since out of order
packets can definitely use up to sk_rcvbuf memory themselves.
2) Even with a fixed memory truesize check, prequeue can be filled
by thousands of packets. When prequeue needs to be flushed, either
from sofirq context (in tcp_prequeue() or timer code), or process
context (in tcp_prequeue_process()), this adds a latency spike
which is often not desirable.
I added a fixed limit of 32 packets, as this translated to a max
flush time of 60 us on my test hosts.
Also note that all packets in prequeue are not accounted for tcp_mem,
since they are not charged against sk_forward_alloc at this point.
This is probably not a big deal.
Note that this might increase LINUX_MIB_TCPPREQUEUEDROPPED counts,
which is misnamed, as packets are not dropped at all, but rather pushed
to the stack (where they can be either consumed or dropped)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is never called with a NULL "buf" and anyway, we dereference 's' on
the lines before so it would Oops before we reach the check.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There's no need to calculate rps hash if it was not enabled. So this
patch export rps_needed and check it before trying to get rps
hash. Tests (using pktgen to inject packets to guest) shows this can
improve pps about 13% (when rps is disabled).
Before:
~1150000 pps
After:
~1300000 pps
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
----
Changes from V1:
- Fix build when CONFIG_RPS is not set
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds an eor bit to the TCP_SKB_CB. When MSG_EOR
is passed to tcp_sendmsg, the eor bit will be set at the skb
containing the last byte of the userland's msg. The eor bit
will prevent data from appending to that skb in the future.
The change in do_tcp_sendpages is to honor the eor set
during the previous tcp_sendmsg(MSG_EOR) call.
This patch handles the tcp_sendmsg case. The followup patches
will handle other skb coalescing and fragment cases.
One potential use case is to use MSG_EOR with
SOF_TIMESTAMPING_TX_ACK to get a more accurate
TCP ack timestamping on application protocol with
multiple outgoing response messages (e.g. HTTP2).
Packetdrill script for testing:
~~~~~~
+0 `sysctl -q -w net.ipv4.tcp_min_tso_segs=10`
+0 `sysctl -q -w net.ipv4.tcp_no_metrics_save=1`
+0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
+0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
+0 bind(3, ..., ...) = 0
+0 listen(3, 1) = 0
0.100 < S 0:0(0) win 32792 <mss 1460,sackOK,nop,nop,nop,wscale 7>
0.100 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 7>
0.200 < . 1:1(0) ack 1 win 257
0.200 accept(3, ..., ...) = 4
+0 setsockopt(4, SOL_TCP, TCP_NODELAY, [1], 4) = 0
0.200 write(4, ..., 14600) = 14600
0.200 sendto(4, ..., 730, MSG_EOR, ..., ...) = 730
0.200 sendto(4, ..., 730, MSG_EOR, ..., ...) = 730
0.200 > . 1:7301(7300) ack 1
0.200 > P. 7301:14601(7300) ack 1
0.300 < . 1:1(0) ack 14601 win 257
0.300 > P. 14601:15331(730) ack 1
0.300 > P. 15331:16061(730) ack 1
0.400 < . 1:1(0) ack 16061 win 257
0.400 close(4) = 0
0.400 > F. 16061:16061(0) ack 1
0.400 < F. 1:1(0) ack 16062 win 257
0.400 > . 16062:16062(0) ack 2
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Suggested-by: Eric Dumazet <edumazet@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The SKBTX_ACK_TSTAMP flag is set in skb_shinfo->tx_flags when
the timestamp of the TCP acknowledgement should be reported on
error queue. Since accessing skb_shinfo is likely to incur a
cache-line miss at the time of receiving the ack, the
txstamp_ack bit was added in tcp_skb_cb, which is set iff
the SKBTX_ACK_TSTAMP flag is set for an skb. This makes
SKBTX_ACK_TSTAMP flag redundant.
Remove the SKBTX_ACK_TSTAMP and instead use the txstamp_ack bit
everywhere.
Note that this frees one bit in shinfo->tx_flags.
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Suggested-by: Willem de Bruijn <willemb@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Remove the redundant check for sk->sk_tsflags in tcp_tx_timestamp.
tcp_tx_timestamp() receives the tsflags as a parameter. As a
result the "sk->sk_tsflags || tsflags" is redundant, since
tsflags already includes sk->sk_tsflags plus overrides from
control messages.
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is nothing related to BH in SNMP counters anymore,
since linux-3.0.
Rename helpers to use __ prefix instead of _BH prefix,
for contexts where preemption is disabled.
This more closely matches convention used to update
percpu variables.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rename IP6_UPD_PO_STATS_BH() to __IP6_UPD_PO_STATS()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rename IP6_INC_STATS_BH() to __IP6_INC_STATS()
and IP6_ADD_STATS_BH() to __IP6_ADD_STATS()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rename NET_INC_STATS_BH() to __NET_INC_STATS()
and NET_ADD_STATS_BH() to __NET_ADD_STATS()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rename IP_UPD_PO_STATS_BH() to __IP_UPD_PO_STATS()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rename ICMP6_INC_STATS_BH() to __ICMP6_INC_STATS()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rename IP_INC_STATS_BH() to __IP_INC_STATS(), to
better express this is used in non preemptible context.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rename SCTP_INC_STATS_BH() to __SCTP_INC_STATS()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rename UDP_INC_STATS_BH() to __UDP_INC_STATS(),
and UDP6_INC_STATS_BH() to __UDP6_INC_STATS()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rename ICMP_INC_STATS_BH() to __ICMP_INC_STATS()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rename DCCP_INC_STATS_BH() to __DCCP_INC_STATS()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In the old days (before linux-3.0), SNMP counters were duplicated,
one for user context, and one for BH context.
After commit 8f0ea0fe3a03 ("snmp: reduce percpu needs by 50%")
we have a single copy, and what really matters is preemption being
enabled or disabled, since we use this_cpu_inc() or __this_cpu_inc()
respectively.
We therefore kill SNMP_INC_STATS_USER(), SNMP_ADD_STATS_USER(),
NET_INC_STATS_USER(), NET_ADD_STATS_USER(), SCTP_INC_STATS_USER(),
SNMP_INC_STATS64_USER(), SNMP_ADD_STATS64_USER(), TCP_ADD_STATS_USER(),
UDP_INC_STATS_USER(), UDP6_INC_STATS_USER(), and XFRM_INC_STATS_USER()
Following patches will rename __BH helpers to make clear their
usage is not tied to BH being disabled.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Minor overlapping changes in the conflicts.
In the macsec case, the change of the default ID macro
name overlapped with the 64-bit netlink attribute alignment
fixes in net-next.
Signed-off-by: David S. Miller <davem@davemloft.net>
Similar to 3bfd847203c6 ("net: Use passed in table for nexthop lookups")
for IPv4, if the route spec contains a table id use that to lookup the
next hop first and fall back to a full lookup if it fails (per the fix
4c9bcd117918b ("net: Fix nexthop lookups")).
Example:
root@kenny:~# ip -6 ro ls table red
local 2100:1::1 dev lo proto none metric 0 pref medium
2100:1::/120 dev eth1 proto kernel metric 256 pref medium
local 2100:2::1 dev lo proto none metric 0 pref medium
2100:2::/120 dev eth2 proto kernel metric 256 pref medium
local fe80::e0:f9ff:fe09:3cac dev lo proto none metric 0 pref medium
local fe80::e0:f9ff:fe1c:b974 dev lo proto none metric 0 pref medium
fe80::/64 dev eth1 proto kernel metric 256 pref medium
fe80::/64 dev eth2 proto kernel metric 256 pref medium
ff00::/8 dev red metric 256 pref medium
ff00::/8 dev eth1 metric 256 pref medium
ff00::/8 dev eth2 metric 256 pref medium
unreachable default dev lo metric 240 error -113 pref medium
root@kenny:~# ip -6 ro add table red 2100:3::/64 via 2100:1::64
RTNETLINK answers: No route to host
Route add fails even though 2100:1::64 is a reachable next hop:
root@kenny:~# ping6 -I red 2100:1::64
ping6: Warning: source address might be selected on device other than red.
PING 2100:1::64(2100:1::64) from 2100:1::1 red: 56 data bytes
64 bytes from 2100:1::64: icmp_seq=1 ttl=64 time=1.33 ms
With this patch:
root@kenny:~# ip -6 ro add table red 2100:3::/64 via 2100:1::64
root@kenny:~# ip -6 ro ls table red
local 2100:1::1 dev lo proto none metric 0 pref medium
2100:1::/120 dev eth1 proto kernel metric 256 pref medium
local 2100:2::1 dev lo proto none metric 0 pref medium
2100:2::/120 dev eth2 proto kernel metric 256 pref medium
2100:3::/64 via 2100:1::64 dev eth1 metric 1024 pref medium
local fe80::e0:f9ff:fe09:3cac dev lo proto none metric 0 pref medium
local fe80::e0:f9ff:fe1c:b974 dev lo proto none metric 0 pref medium
fe80::/64 dev eth1 proto kernel metric 256 pref medium
fe80::/64 dev eth2 proto kernel metric 256 pref medium
ff00::/8 dev red metric 256 pref medium
ff00::/8 dev eth1 metric 256 pref medium
ff00::/8 dev eth2 metric 256 pref medium
unreachable default dev lo metric 240 error -113 pref medium
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
No more users in the tree, remove NETDEV_TX_LOCKED support.
Adds another hole in softnet_stats struct, but better than keeping
the unused collision counter around.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
For sctp assoc, when rcvbuf_policy is set, it will has it's own
rmem_alloc, when we dump asoc info in sctp_diag, we should use that
value on RMEM_ALLOC as well, just like WMEM_ALLOC.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Johan Hedberg says:
====================
pull request: bluetooth-next 2016-04-26
Here's another set of Bluetooth & 802.15.4 patches for the 4.7 kernel:
- Cleanups & refactoring of ieee802154 & 6lowpan code
- Security related additions to ieee802154 and mrf24j40 driver
- Memory corruption fix to Bluetooth 6lowpan code
- Race condition fix in vhci driver
- Enhancements to the atusb 802.15.4 driver
Please let me know if there are any issues pulling. Thanks.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
I also fix commit 8b32ab9e6ef1: use nla_total_size_64bit() for
OVS_FLOW_ATTR_USED in ovs_flow_cmd_msg_size().
Fixes: 8b32ab9e6ef1 ("ovs: use nla_put_u64_64bit()")
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
I also fix the value of INET_DIAG_MAX. It's wrong since commit 8f840e47f190
which is only in net-next right now, thus I didn't make a separate patch.
Fixes: 8f840e47f190 ("sctp: add the sctp_diag.c file")
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It was a simple idea -- save IPv6 configured addresses on a link down
so that IPv6 behaves similar to IPv4. As always the devil is in the
details and the IPv6 stack as too many behavioral differences from IPv4
making the simple idea more complicated than it needs to be.
The current implementation for keeping IPv6 addresses can panic or spit
out a warning in one of many paths:
1. IPv6 route gets an IPv4 route as its 'next' which causes a panic in
rt6_fill_node while handling a route dump request.
2. rt->dst.obsolete is set to DST_OBSOLETE_DEAD hitting the WARN_ON in
fib6_del
3. Panic in fib6_purge_rt because rt6i_ref count is not 1.
The root cause of all these is references related to the host route for
an address that is retained.
So, this patch deletes the host route every time the ifdown loop runs.
Since the host route is deleted and will be re-generated an up there is
no longer a need for the l3mdev fix up. On the 'admin up' side move
addrconf_permanent_addr into the NETDEV_UP event handling so that it
runs only once versus on UP and CHANGE events.
All of the current panics and warnings appear to be related to
addresses on the loopback device, but given the catastrophic nature when
a bug is triggered this patch takes the conservative approach and evicts
all host routes rather than trying to determine when it can be re-used
and when it can not. That can be a later optimizaton if desired.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts commit 841645b5f2dfceac69b78fcd0c9050868d41ea61.
Ok, this puts the feature back. I've decided to apply David A.'s
bug fix and run with that rather than make everyone wait another
whole release for this feature.
Signed-off-by: David S. Miller <davem@davemloft.net>
Support checksum neutral ILA as described in the ILA draft. The low
order 16 bits of the identifier are used to contain the checksum
adjustment value.
The csum-mode parameter is added to described checksum processing. There
are three values:
- adjust transport checksum (previous behavior)
- do checksum neutral mapping
- do nothing
On output the csum-mode in the ila_params is checked and acted on. If
mode is checksum neutral mapping then to mapping and set C-bit.
On input, C-bit is checked. If it is set checksum-netural mapping is
done (regardless of csum-mode in ila params) and C-bit will be cleared.
If it is not set then action in csum-mode is taken.
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
