This patch fixes an uninitialised return value error in
ila_xlat_nl_cmd_flush.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 6c4128f658 ("rhashtable: Remove obsolete...")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
The rhashtable_walk_init function has been obsolete for more than
two years. This patch finally converts its last users over to
rhashtable_walk_enter and removes it.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Add ILA_CMD_FLUSH netlink command to clear the ILA translation table.
Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Create a main ila file that contains the module initialization functions
as well as netlink definitions. Previously these were defined in
ila_xlat and ila_common. This approach allows better extensibility.
Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
To allocate the array of bucket locks for the hash table we now
call library function alloc_bucket_spinlocks.
Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Perform better EAGAIN handling, handle case where ila_dump_info
fails and we missed objects in the dump, and add a skip index
to skip over ila entires in a list on a rhashtable node that have
already been visited (by a previous call to ila_nl_dump).
Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Most callers of rhashtable_walk_start don't care about a resize event
which is indicated by a return value of -EAGAIN. So calls to
rhashtable_walk_start are wrapped wih code to ignore -EAGAIN. Something
like this is common:
ret = rhashtable_walk_start(rhiter);
if (ret && ret != -EAGAIN)
goto out;
Since zero and -EAGAIN are the only possible return values from the
function this check is pointless. The condition never evaluates to true.
This patch changes rhashtable_walk_start to return void. This simplifies
code for the callers that ignore -EAGAIN. For the few cases where the
caller cares about the resize event, particularly where the table can be
walked in mulitple parts for netlink or seq file dump, the function
rhashtable_walk_start_check has been added that returns -EAGAIN on a
resize event.
Signed-off-by: Tom Herbert <tom@quantonium.net>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
In LWT tunnels both an input and output route method is defined.
If both of these are executed in the same path then double translation
happens and the effect is not correct.
This patch adds a new attribute that indicates the hook type. Two
values are defined for route output and route output. ILA
translation is only done for the one that is set. The default is
to enable ILA on route output.
Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Allow identifier to be explicitly configured for a mapping.
This can either be one of the identifier types specified in the
ILA draft or a value of ILA_ATYPE_USE_FORMAT which means the
identifier type is inferred from the identifier type field.
If a value other than ILA_ATYPE_USE_FORMAT is set for a
mapping then it is assumed that the identifier type field is
not present in an identifier.
Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add checksum neutral auto that performs checksum neutral mapping
without using the C-bit. This is enabled by configuration of
a mapping.
The checksum neutral function has been split into
ila_csum_do_neutral_fmt and ila_csum_do_neutral_nofmt. The former
handles the C-bit and includes it in the adjustment value. The latter
just sets the adjustment value on the locator diff only.
Added configuration for checksum neutral map aut in ila_lwt
and ila_xlat.
Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Consolidate computing checksum diff into one function.
Add get_csum_diff_iaddr that computes the checksum diff between
an address argument and locator being written. get_csum_diff
calls this using the destination address in the IP header as
the argument.
Also moved ila_init_saved_csum to be close to the checksum
diff functions.
Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We no longer place these on a list so they can be const.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
While discussing the possible merits of clang warning about unused initialized
functions, I found one function that was clearly meant to be called but
never actually is.
__ila_hash_secret_init() initializes the hash value for the ila locator,
apparently this is intended to prevent hash collision attacks, but this ends
up being a read-only zero constant since there is no caller. I could find
no indication of why it was never called, the earliest patch submission
for the module already was like this. If my interpretation is right, we
certainly want to backport the patch to stable kernels as well.
I considered adding it to the ila_xlat_init callback, but for best effect
the random data is read as late as possible, just before it is first used.
The underlying net_get_random_once() is already highly optimized to avoid
overhead when called frequently.
Fixes: 7f00feaf10 ("ila: Add generic ILA translation facility")
Cc: stable@vger.kernel.org
Link: https://www.spinics.net/lists/kernel/msg2527243.html
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pass extack arg down to lwtunnel_build_state and the build_state callbacks.
Add messages for failures in lwtunnel_build_state, and add the extarg to
nla_parse where possible in the build_state callbacks.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This warning:
net/ipv6/ila/ila_lwt.c: In function ‘ila_output’:
net/ipv6/ila/ila_lwt.c:42:6: warning: variable ‘err’ set but not used [-Wunused-but-set-variable]
It looks like the code attempts to set propagate different error
values, but always returned -EINVAL.
Compile tested only. Needs review by original author.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
alloc_ila_locks seemed to c&p from alloc_bucket_locks allocation pattern
which is quite unusual. The default allocation size is 320 *
sizeof(spinlock_t) which is sub page unless lockdep is enabled when the
performance benefit is really questionable and not worth the subtle code
IMHO. Also note that the context when we call ila_init_net (modprobe or
a task creating a net namespace) has to be properly configured.
Let's just simplify the code and use kvmalloc helper which is a
transparent way to use kmalloc with vmalloc fallback.
Link: http://lkml.kernel.org/r/20170306103032.2540-5-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Tom Herbert <tom@herbertland.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pass the new extended ACK reporting struct to all of the generic
netlink parsing functions. For now, pass NULL in almost all callers
(except for some in the core.)
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Nothing about lwt state requires a device reference, so remove the
input argument.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Modules implementing lwtunnel ops should not be allowed to unload
while there is state alive using those ops, so specify the owning
module for all lwtunnel ops.
Signed-off-by: Robert Shearman <rshearma@brocade.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
commit ca26893f05 ("rhashtable: Add rhlist interface")
added a field to rhashtable_iter so that length became 56 bytes
and would exceed the size of args in netlink_callback (which is
48 bytes). The netlink diag dump function already has been
allocating a iter structure and storing the pointed to that
in the args of netlink_callback. ila_xlat also uses
rhahstable_iter but is still putting that directly in
the arg block. Now since rhashtable_iter size is increased
we are overwriting beyond the structure. The next field
happens to be cb_mutex pointer in netlink_sock and hence the crash.
Fix is to alloc the rhashtable_iter and save it as pointer
in arg.
Tested:
modprobe ila
./ip ila add loc 3333:0:0:0 loc_match 2222:0:0:1,
./ip ila list # NO crash now
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now genl_register_family() is the only thing (other than the
users themselves, perhaps, but I didn't find any doing that)
writing to the family struct.
In all families that I found, genl_register_family() is only
called from __init functions (some indirectly, in which case
I've add __init annotations to clarifly things), so all can
actually be marked __ro_after_init.
This protects the data structure from accidental corruption.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Instead of providing macros/inline functions to initialize
the families, make all users initialize them statically and
get rid of the macros.
This reduces the kernel code size by about 1.6k on x86-64
(with allyesconfig).
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Static family IDs have never really been used, the only
use case was the workaround I introduced for those users
that assumed their family ID was also their multicast
group ID.
Additionally, because static family IDs would never be
reserved by the generic netlink code, using a relatively
low ID would only work for built-in families that can be
registered immediately after generic netlink is started,
which is basically only the control family (apart from
the workaround code, which I also had to add code for so
it would reserve those IDs)
Thus, anything other than GENL_ID_GENERATE is flawed and
luckily not used except in the cases I mentioned. Move
those workarounds into a few lines of code, and then get
rid of GENL_ID_GENERATE entirely, making it more robust.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The field is initialized by ILA and MPLS but never used. Remove it.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Tailroom is supposed to be of length sizeof(struct ila_lwt) but
sizeof(struct ila_params) is currently allocated.
This leads to the dst_cache and connected member of ila_lwt being
referenced out of bounds.
struct ila_lwt {
struct ila_params p;
struct dst_cache dst_cache;
u32 connected : 1;
};
Fixes: 65d7ab8de5 ("net: Identifier Locator Addressing module")
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
If the gateway is set on an ILA route we don't need to bother with using
the destination cache in the ILA route. Translation does not change the
routing in this case so we can stick with orig_output in the lwstate
output function.
Tested: Ran netperf with and without gateway for LWT route.
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a dst_cache to ila_lwt structure. This holds a cached route for the
translated address. In ila_output we now perform a route lookup after
translation and if possible (destination in original route is full 128
bits) we set the dst_cache. Subsequent calls to ila_output can then use
the cache to avoid the route lookup.
This eliminates the need to set the gateway on ILA routes as previously
was being done. Now we can do something like:
./ip route add 3333::2000:0:0:2/128 encap ila 2222:0:0:2 \
csum-mode neutral-map dev eth0 ## No via needed!
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Adapt KCM to use the stream parser. This mostly involves removing
the RX handling and setting up the strparser using the interface.
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The algorithm for checksum neutral mapping is incorrect. This problem
was being hidden since we were previously always performing checksum
offload on the translated addresses and only with IPv6 HW csum.
Enabling an ILA router shows the issue.
Corrected algorithm:
old_loc is the original locator in the packet, new_loc is the value
to overwrite with and is found in the lookup table. old_flag is
the old flag value (zero of CSUM_NEUTRAL_FLAG) and new_flag is
then (old_flag ^ CSUM_NEUTRAL_FLAG) & CSUM_NEUTRAL_FLAG.
Need SUM(new_id + new_flag + diff) == SUM(old_id + old_flag) for
checksum neutral translation.
Solving for diff gives:
diff = (old_id - new_id) + (old_flag - new_flag)
compute_csum_diff8(new_id, old_id) gives old_id - new_id
If old_flag is set
old_flag - new_flag = old_flag = CSUM_NEUTRAL_FLAG
Else
old_flag - new_flag = -new_flag = ~CSUM_NEUTRAL_FLAG
Tested:
- Implemented a user space program that creates random addresses
and random locators to overwrite. Compares the checksum over
the address before and after translation (must always be equal)
- Enabled ILA router and showed proper operation.
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When setting up ILA in a router we noticed that the the encapsulation
is invoked twice: once in the route input path and again upon route
output. To resolve this we add a flag set_csum_neutral for the
ila_update_ipv6_locator. If this flag is set and the checksum
neutral bit is also set we assume that checksum-neutral translation
has already been performed and take no further action. The
flag is set only in ila_output path. The flag is not set for ila_input and
ila_xlat.
Tested:
Used 3 netns to set to emulate a router and two hosts. The router
translates SIR addresses between the two destinations in other two netns.
Verified ping and netperf are functional.
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The handler 'ila_fill_encap_info' adds two attributes: ILA_ATTR_LOCATOR
and ILA_ATTR_CSUM_MODE.
nla_total_size_64bit() must be use for ILA_ATTR_LOCATOR.
Also, do nla_put_u8 instead of nla_put_u64 for ILA_ATTR_CSUM_MODE.
Fixes: f13a82d87b ("ipv6: use nla_put_u64_64bit()")
Fixes: 90bfe662db ("ila: add checksum neutral ILA translations")
Reported-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conflicts:
net/ipv4/ip_gre.c
Minor conflicts between tunnel bug fixes in net and
ipv6 tunnel cleanups in net-next.
Signed-off-by: David S. Miller <davem@davemloft.net>
The handler 'ila_fill_encap_info' adds one attribute: ILA_ATTR_LOCATOR.
Fixes: 65d7ab8de5 ("net: Identifier Locator Addressing module")
CC: Tom Herbert <tom@herbertland.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
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>
Change model of xlat to be used only for input where lookup is done on
the locator part of an address (comparing to locator_match as key
in rhashtable). This is needed for checksum neutral translation
which obfuscates the low order 16 bits of the identifier. It also
permits hosts to be in muliple ILA domains (each locator can map
to a different SIR address). A check is also added to disallow
translating non-ILA addresses (check of type in identifier).
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add structures for identifiers, locators, and an ila address which
is composed of a locator and identifier and in6_addr can be cast to
it. This includes a three bit type field and enums for the types defined
in ILA I-D.
In ILA lwt don't allow user to set a translation for a non-ILA
address (type of identifier is zero meaning it is an IID). This also
requires that the destination prefix is at least 65 bytes (64
bit locator and first byte of identifier).
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In certain cases, the 802.11 mesh pathtable code wants to
iterate over all of the entries in the forwarding table from
the receive path, which is inside an RCU read-side critical
section. Enable walks inside atomic sections by allowing
GFP_ATOMIC allocations for the walker state.
Change all existing callsites to pass in GFP_KERNEL.
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Bob Copeland <me@bobcopeland.com>
[also adjust gfs2/glock.c and rhashtable tests]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Avoid users having to manually load the module by adding a module
alias allowing it to be autoloaded by the lwt infra.
Signed-off-by: Robert Shearman <rshearma@brocade.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch implements an ILA tanslation table. This table can be
configured with identifier to locator mappings, and can be be queried
to resolve a mapping. Queries can be parameterized based on interface,
direction (incoming or outoing), and matching locator. The table is
implemented using rhashtable and is configured via netlink (through
"ip ila .." in iproute).
The table may be used as alternative means to do do ILA tanslations
other than the lw tunnels
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Create ila directory in preparation for supporting other hooks in the
kernel than LWT for doing ILA. This includes:
- Moving ila.c to ila/ila_lwt.c
- Splitting out some common functions into ila_common.c
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
