Using a combination of connected and un-connected sockets, Dmitry
was able to trigger soft lockups with his fuzzer.
The problem is that sockets in the SO_REUSEPORT array might have
different scores.
Right after sk2=socket(), setsockopt(sk2,...,SO_REUSEPORT, on) and
bind(sk2, ...), but _before_ the connect(sk2) is done, sk2 is added into
the soreuseport array, with a score which is smaller than the score of
first socket sk1 found in hash table (I am speaking of the regular UDP
hash table), if sk1 had the connect() done, giving a +8 to its score.
hash bucket [X] -> sk1 -> sk2 -> NULL
sk1 score = 14 (because it did a connect())
sk2 score = 6
SO_REUSEPORT fast selection is an optimization. If it turns out the
score of the selected socket does not match score of first socket, just
fallback to old SO_REUSEPORT logic instead of trying to be too smart.
Normal SO_REUSEPORT users do not mix different kind of sockets, as this
mechanism is used for load balance traffic.
Fixes: e32ea7e747 ("soreuseport: fast reuseport UDP socket selection")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Craig Gallek <kraigatgoog@gmail.com>
Acked-by: Craig Gallek <kraig@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This socket-lookup path did not pass along the skb in question
in my original BPF-based socket selection patch. The skb in the
udpN_lib_lookup2 path can be used for BPF-based socket selection just
like it is in the 'traditional' udpN_lib_lookup path.
udpN_lib_lookup2 kicks in when there are greater than 10 sockets in
the same hlist slot. Coincidentally, I chose 10 sockets per
reuseport group in my functional test, so the lookup2 path was not
excersised. This adds an additional set of tests with 20 sockets.
Fixes: 538950a1b7 ("soreuseport: setsockopt SO_ATTACH_REUSEPORT_[CE]BPF")
Fixes: 3ca8e40299 ("soreuseport: BPF selection functional test")
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Craig Gallek <kraig@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Expose socket options for setting a classic or extended BPF program
for use when selecting sockets in an SO_REUSEPORT group. These options
can be used on the first socket to belong to a group before bind or
on any socket in the group after bind.
This change includes refactoring of the existing sk_filter code to
allow reuse of the existing BPF filter validation checks.
Signed-off-by: Craig Gallek <kraig@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Include a struct sock_reuseport instance when a UDP socket binds to
a specific address for the first time with the reuseport flag set.
When selecting a socket for an incoming UDP packet, use the information
available in sock_reuseport if present.
This required adding an additional field to the UDP source address
equality function to differentiate between exact and wildcard matches.
The original use case allowed wildcard matches when checking for
existing port uses during bind. The new use case of adding a socket
to a reuseport group requires exact address matching.
Performance test (using a machine with 2 CPU sockets and a total of
48 cores): Create reuseport groups of varying size. Use one socket
from this group per user thread (pinning each thread to a different
core) calling recvmmsg in a tight loop. Record number of messages
received per second while saturating a 10G link.
10 sockets: 18% increase (~2.8M -> 3.3M pkts/s)
20 sockets: 14% increase (~2.9M -> 3.3M pkts/s)
40 sockets: 13% increase (~3.0M -> 3.4M pkts/s)
This work is based off a similar implementation written by
Ying Cai <ycai@google.com> for implementing policy-based reuseport
selection.
Signed-off-by: Craig Gallek <kraig@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Backport of this upstream commit into stable kernels :
89c22d8c3b ("net: Fix skb csum races when peeking")
exposed a bug in udp stack vs MSG_PEEK support, when user provides
a buffer smaller than skb payload.
In this case,
skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr),
msg->msg_iov);
returns -EFAULT.
This bug does not happen in upstream kernels since Al Viro did a great
job to replace this into :
skb_copy_and_csum_datagram_msg(skb, sizeof(struct udphdr), msg);
This variant is safe vs short buffers.
For the time being, instead reverting Herbert Xu patch and add back
skb->ip_summed invalid changes, simply store the result of
udp_lib_checksum_complete() so that we avoid computing the checksum a
second time, and avoid the problematic
skb_copy_and_csum_datagram_iovec() call.
This patch can be applied on recent kernels as it avoids a double
checksumming, then backported to stable kernels as a bug fix.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch addresses multiple problems :
UDP/RAW sendmsg() need to get a stable struct ipv6_txoptions
while socket is not locked : Other threads can change np->opt
concurrently. Dmitry posted a syzkaller
(http://github.com/google/syzkaller) program desmonstrating
use-after-free.
Starting with TCP/DCCP lockless listeners, tcp_v6_syn_recv_sock()
and dccp_v6_request_recv_sock() also need to use RCU protection
to dereference np->opt once (before calling ipv6_dup_options())
This patch adds full RCU protection to np->opt
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
SO_INCOMING_CPU as added in commit 2c8c56e15d was a getsockopt() command
to fetch incoming cpu handling a particular TCP flow after accept()
This commits adds setsockopt() support and extends SO_REUSEPORT selection
logic : If a TCP listener or UDP socket has this option set, a packet is
delivered to this socket only if CPU handling the packet matches the specified
one.
This allows to build very efficient TCP servers, using one listener per
RX queue, as the associated TCP listener should only accept flows handled
in softirq by the same cpu.
This provides optimal NUMA behavior and keep cpu caches hot.
Note that __inet_lookup_listener() still has to iterate over the list of
all listeners. Following patch puts sk_refcnt in a different cache line
to let this iteration hit only shared and read mostly cache lines.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Change brace placement to be in line with coding standards
Signed-off-by: Ian Morris <ipm@chirality.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
We have two problems in UDP stack related to bogus checksums :
1) We return -EAGAIN to application even if receive queue is not empty.
This breaks applications using edge trigger epoll()
2) Under UDP flood, we can loop forever without yielding to other
processes, potentially hanging the host, especially on non SMP.
This patch is an attempt to make things better.
We might in the future add extra support for rt applications
wanting to better control time spent doing a recv() in a hostile
environment. For example we could validate checksums before queuing
packets in socket receive queue.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit <5cf3d46192fc> ("udp: Simplify__udp*_lib_mcast_deliver")
simplified the filter for incoming IPv6 multicast but removed
the check of the local socket address and the UDP destination
address.
This patch restores the filter to prevent sockets bound to a IPv6
multicast IP to receive other UDP traffic link unicast.
Signed-off-by: Henning Rogge <hrogge@gmail.com>
Fixes: 5cf3d46192 ("udp: Simplify__udp*_lib_mcast_deliver")
Cc: "David S. Miller" <davem@davemloft.net>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The ipv6 code uses a mixture of coding styles. In some instances check for NULL
pointer is done as x != NULL and sometimes as x. x is preferred according to
checkpatch and this patch makes the code consistent by adopting the latter
form.
No changes detected by objdiff.
Signed-off-by: Ian Morris <ipm@chirality.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
The ipv6 code uses a mixture of coding styles. In some instances check for NULL
pointer is done as x == NULL and sometimes as !x. !x is preferred according to
checkpatch and this patch makes the code consistent by adopting the latter
form.
No changes detected by objdiff.
Signed-off-by: Ian Morris <ipm@chirality.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
const qualifiers ease code review by making clear
which objects are not written in a function.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After TIPC doesn't depend on iocb argument in its internal
implementations of sendmsg() and recvmsg() hooks defined in proto
structure, no any user is using iocb argument in them at all now.
Then we can drop the redundant iocb argument completely from kinds of
implementations of both sendmsg() and recvmsg() in the entire
networking stack.
Cc: Christoph Hellwig <hch@lst.de>
Suggested-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit adds the same functionaliy to IPv6 that
commit 903ab86d19
Author: Herbert Xu <herbert@gondor.apana.org.au>
Date: Tue Mar 1 02:36:48 2011 +0000
udp: Add lockless transmit path
added to IPv4.
UDP transmit path can now run without a socket lock,
thus allowing multiple threads to send to a single socket
more efficiently.
This is only used when corking/MSG_MORE is not used.
Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that we can individually construct IPv6 skbs to send, add a
udpv6_send_skb() function to populate the udp header and send the
skb. This allows udp_v6_push_pending_frames() to re-use this
function as well as enables us to add lockless sendmsg() support.
Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move convert_csum from udp_sock to inet_sock. This allows the
possibility that we can use convert checksum for different types
of sockets and also allows convert checksum to be enabled from
inet layer (what we'll want to do when enabling IP_CHECKSUM cmsg).
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The compute_score functions are a bit difficult to read.
Neaten them a bit to reduce object sizes and make them a
bit more intelligible.
Return early to avoid indentation and avoid unnecessary
initializations.
(allyesconfig, but w/ -O2 and no profiling)
$ size net/ipv[46]/udp.o.*
text data bss dec hex filename
28680 1184 25 29889 74c1 net/ipv4/udp.o.new
28756 1184 25 29965 750d net/ipv4/udp.o.old
17600 1010 2 18612 48b4 net/ipv6/udp.o.new
17632 1010 2 18644 48d4 net/ipv6/udp.o.old
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This change has no functional impact and simply addresses some coding
style issues detected by checkpatch. Specifically this change
adjusts "if" statements which also include the assignment of a
variable.
No changes to the resultant object files result as determined by objdiff.
Signed-off-by: Ian Morris <ipm@chirality.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use the more common dynamic_debug capable net_dbg_ratelimited
and remove the LIMIT_NETDEBUG macro.
All messages are still ratelimited.
Some KERN_<LEVEL> uses are changed to KERN_DEBUG.
This may have some negative impact on messages that were
emitted at KERN_INFO that are not not enabled at all unless
DEBUG is defined or dynamic_debug is enabled. Even so,
these messages are now _not_ emitted by default.
This also eliminates the use of the net_msg_warn sysctl
"/proc/sys/net/core/warnings". For backward compatibility,
the sysctl is not removed, but it has no function. The extern
declaration of net_msg_warn is removed from sock.h and made
static in net/core/sysctl_net_core.c
Miscellanea:
o Update the sysctl documentation
o Remove the embedded uses of pr_fmt
o Coalesce format fragments
o Realign arguments
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Alternative to RPS/RFS is to use hardware support for multiple
queues.
Then split a set of million of sockets into worker threads, each
one using epoll() to manage events on its own socket pool.
Ideally, we want one thread per RX/TX queue/cpu, but we have no way to
know after accept() or connect() on which queue/cpu a socket is managed.
We normally use one cpu per RX queue (IRQ smp_affinity being properly
set), so remembering on socket structure which cpu delivered last packet
is enough to solve the problem.
After accept(), connect(), or even file descriptor passing around
processes, applications can use :
int cpu;
socklen_t len = sizeof(cpu);
getsockopt(fd, SOL_SOCKET, SO_INCOMING_CPU, &cpu, &len);
And use this information to put the socket into the right silo
for optimal performance, as all networking stack should run
on the appropriate cpu, without need to send IPI (RPS/RFS).
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As NIC multicast filtering isn't perfect, and some platforms are
quite content to spew broadcasts, we should not trigger an event
for skb:kfree_skb when we do not have a match for such an incoming
datagram. We do though want to avoid sweeping the matter under the
rug entirely, so increment a suitable statistic.
This incorporates feedback from David L. Stevens, Karl Neiss and Eric
Dumazet.
V3 - use bool per David Miller
Signed-off-by: Rick Jones <rick.jones2@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This encapsulates all of the skb_copy_datagram_iovec() callers
with call argument signature "skb, offset, msghdr->msg_iov, length".
When we move to iov_iters in the networking, the iov_iter object will
sit in the msghdr.
Having a helper like this means there will be less places to touch
during that transformation.
Based upon descriptions and patch from Al Viro.
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for doing CHECKSUM_UNNECESSARY to CHECKSUM_COMPLETE
conversion in UDP tunneling path.
In the normal UDP path, we call skb_checksum_try_convert after locating
the UDP socket. The check is that checksum conversion is enabled for
the socket (new flag in UDP socket) and that checksum field is
non-zero.
In the UDP GRO path, we call skb_gro_checksum_try_convert after
checksum is validated and checksum field is non-zero. Since this is
already in GRO we assume that checksum conversion is always wanted.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch makes no changes to the logic of the code but simply addresses
coding style issues as detected by checkpatch.
Both objdump and diff -w show no differences.
A number of items are addressed in this patch:
* Multiple spaces converted to tabs
* Spaces before tabs removed.
* Spaces in pointer typing cleansed (char *)foo etc.
* Remove space after sizeof
* Ensure spacing around comparators such as if statements.
Signed-off-by: Ian Morris <ipm@chirality.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Replace open codings of (((u64) <x> * <y>) >> 32) with reciprocal_scale().
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
When dealing with ICMPv[46] Error Message, function icmp_socket_deliver()
and icmpv6_notify() do some valid checks on packet's length, but then some
protocols check packet's length redaudantly. So remove those duplicated
statements, and increase counter ICMP_MIB_INERRORS/ICMP6_MIB_INERRORS in
function icmp_socket_deliver() and icmpv6_notify() respectively.
In addition, add missed counter in udp6/udplite6 when socket is NULL.
Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
It hasn't been used since commit 0fd7bac(net: relax rcvbuf limits).
Signed-off-by: Sorin Dumitru <sorin@returnze.ro>
Signed-off-by: David S. Miller <davem@davemloft.net>
Many multicast sources can have the same port which can result in a very
large list when hashing by port only. Hash by address and port instead
if this is the case. This makes multicast more similar to unicast.
On a 24-core machine receiving from 500 multicast sockets on the same
port, before this patch 80% of system CPU was used up by spin locking
and only ~25% of packets were successfully delivered.
With this patch, all packets are delivered and kernel overhead is ~8%
system CPU on spinlocks.
Signed-off-by: David Held <drheld@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Switch to using sk_nulls_for_each which shortens the code and makes it
easier to update.
Signed-off-by: David Held <drheld@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When an UDP application switches from AF_INET to AF_INET6 sockets, we
have a small performance degradation for IPv4 communications because of
extra cache line misses to access ipv6only information.
This can also be noticed for TCP listeners, as ipv6_only_sock() is also
used from __inet_lookup_listener()->compute_score()
This is magnified when SO_REUSEPORT is used.
Move ipv6only into struct sock_common so that it is available at
no extra cost in lookups.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add MIB counters for rcvbuferrors in UDP to help diagnose problems.
Signed-off-by: James M Leddy <james.leddy@redhat.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
To avoid the confusion of having two variables, shrink the function to
only use the parameter variable for looping.
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conflicts:
drivers/net/xen-netback/netback.c
net/core/filter.c
A filter bug fix overlapped some cleanups and a conversion
over to some new insn generation macros.
A xen-netback bug fix overlapped the addition of multi-queue
support.
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit efe4208 ("ipv6: make lookups simpler and faster") introduced a
regression in udp_v6_mcast_next(), resulting in multicast packets not
reaching the destination sockets under certain conditions.
The packet's IPv6 addresses are wrongly compared to the IPv6 addresses
from the function's socket argument, which indicates the starting point
for looping, instead of the loop variable. If the addresses from the
first socket do not match the packet's addresses, no socket in the list
will match.
Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
RFC 6935 permits zero checksums to be used in IPv6 however this is
recommended only for certain tunnel protocols, it does not make
checksums completely optional like they are in IPv4.
This patch restricts the use of IPv6 zero checksums that was previously
intoduced. no_check6_tx and no_check6_rx have been added to control
the use of checksums in UDP6 RX and TX path. The normal
sk_no_check_{rx,tx} settings are not used (this avoids ambiguity when
dealing with a dual stack socket).
A helper function has been added (udp_set_no_check6) which can be
called by tunnel impelmentations to all zero checksums (send on the
socket, and accept them as valid).
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Define separate fields in the sock structure for configuring disabling
checksums in both TX and RX-- sk_no_check_tx and sk_no_check_rx.
The SO_NO_CHECK socket option only affects sk_no_check_tx. Also,
removed UDP_CSUM_* defines since they are no longer necessary.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It doesn't seem like an protocols are setting anything other
than the default, and allowing to arbitrarily disable checksums
for a whole protocol seems dangerous. This can be done on a per
socket basis.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Moving validation of UDP checksum to be done in UDP not encap layer.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 4068579e1e ("net: Implmement
RFC 6936 (zero RX csums for UDP/IPv6)") introduced zero checksums
being allowed for IPv6, but in the case that a socket disallows a
zero checksum on RX we need to sock_put.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
RFC 6936 relaxes the requirement of RFC 2460 that UDP/IPv6 packets which
are received with a zero UDP checksum value must be dropped. RFC 6936
allows zero checksums to support tunnels over UDP.
When sk_no_check is set we allow on a socket we allow a zero IPv6
UDP checksum. This is for both sending zero checksum and accepting
a zero checksum on receive.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This replaces 6 identical code snippets with a call to a new
static inline function.
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We currently don't report IPV6_RECVPKTINFO in cmsg access ancillary data
for IPv4 datagrams on IPv6 sockets.
This patch splits the ip6_datagram_recv_ctl into two functions, one
which handles both protocol families, AF_INET and AF_INET6, while the
ip6_datagram_recv_specific_ctl only handles IPv6 cmsg data.
ip6_datagram_recv_*_ctl never reported back any errors, so we can make
them return void. Also provide a helper for protocols which don't offer dual
personality to further use ip6_datagram_recv_ctl, which is exported to
modules.
I needed to shuffle the code for ping around a bit to make it easier to
implement dual personality for ping ipv6 sockets in future.
Reported-by: Gert Doering <gert@space.net>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is a follow-up patch to f3d3342602 ("net: rework recvmsg
handler msg_name and msg_namelen logic").
DECLARE_SOCKADDR validates that the structure we use for writing the
name information to is not larger than the buffer which is reserved
for msg->msg_name (which is 128 bytes). Also use DECLARE_SOCKADDR
consistently in sendmsg code paths.
Signed-off-by: Steffen Hurrle <steffen@hurrle.net>
Suggested-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Steffen Klassert says:
====================
pull request (net-next): ipsec-next 2013-12-19
1) Use the user supplied policy index instead of a generated one
if present. From Fan Du.
2) Make xfrm migration namespace aware. From Fan Du.
3) Make the xfrm state and policy locks namespace aware. From Fan Du.
4) Remove ancient sleeping when the SA is in acquire state,
we now queue packets to the policy instead. This replaces the
sleeping code.
5) Remove FLOWI_FLAG_CAN_SLEEP. This was used to notify xfrm about the
posibility to sleep. The sleeping code is gone, so remove it.
6) Check user specified spi for IPComp. Thr spi for IPcomp is only
16 bit wide, so check for a valid value. From Fan Du.
7) Export verify_userspi_info to check for valid user supplied spi ranges
with pfkey and netlink. From Fan Du.
8) RFC3173 states that if the total size of a compressed payload and the IPComp
header is not smaller than the size of the original payload, the IP datagram
must be sent in the original non-compressed form. These packets are dropped
by the inbound policy check because they are not transformed. Document the need
to set 'level use' for IPcomp to receive such packets anyway. From Fan Du.
Please pull or let me know if there are problems.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Eric Dumazet