Pablo Neira Ayuso says:
====================
Netfilter fixes for net
The following patchset contains Netfilter fixes for your net tree,
they are:
1) Fix a crash in nf_tables when dictionaries are used from the ruleset,
due to memory corruption, from Florian Westphal.
2) Fix another crash in nf_queue when used with br_netfilter. Also from
Florian.
Both fixes are related to new stuff that got in 4.0-rc.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
This fixes:
====================
net/netfilter/nft_reject.c: In function ‘nft_reject_dump’:
net/netfilter/nft_reject.c:61:2: warning: enumeration value ‘NFT_REJECT_TCP_RST’ not handled in switch [-Wswitch]
switch (priv->type) {
^
net/netfilter/nft_reject.c:61:2: warning: enumeration value ‘NFT_REJECT_ICMPX_UNREACH’ not handled in switch [-Wswi\
tch]
net/netfilter/nft_reject_inet.c: In function ‘nft_reject_inet_dump’:
net/netfilter/nft_reject_inet.c:105:2: warning: enumeration value ‘NFT_REJECT_TCP_RST’ not handled in switch [-Wswi\
tch]
switch (priv->type) {
^
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
NFT_JUMP/GOTO erronously sets length to sizeof(void *).
We then allocate insufficient memory when such element is added to a vmap.
Suggested-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Pablo Neira Ayuso says:
====================
Netfilter updates for net-next
A final pull request, I know it's very late but this time I think it's worth a
bit of rush.
The following patchset contains Netfilter/nf_tables updates for net-next, more
specifically concatenation support and dynamic stateful expression
instantiation.
This also comes with a couple of small patches. One to fix the ebtables.h
userspace header and another to get rid of an obsolete example file in tree
that describes a nf_tables expression.
This time, I decided to paste the original descriptions. This will result in a
rather large commit description, but I think these bytes to keep.
Patrick McHardy says:
====================
netfilter: nf_tables: concatenation support
The following patches add support for concatenations, which allow multi
dimensional exact matches in O(1).
The basic idea is to split the data registers, currently consisting of
4 registers of 16 bytes each, into smaller units, 16 registers of 4
bytes each, and making sure each register store always leaves the
full 32 bit in a well defined state, meaning smaller stores will
zero the remaining bits.
Based on that, we can load multiple adjacent registers with different
values, thereby building a concatenated bigger value, and use that
value for set lookups.
Sets are changed to use variable sized extensions for their key and
data values, removing the fixed limit of 16 bytes while saving memory
if less space is needed.
As a side effect, these patches will allow some nice optimizations in
the future, like using jhash2 in nft_hash, removing the masking in
nft_cmp_fast, optimized data comparison using 32 bit word size etc.
These are not done so far however.
The patches are split up as follows:
* the first five patches add length validation to register loads and
stores to make sure we stay within bounds and prepare the validation
functions for the new addressing mode
* the next patches prepare for changing to 32 bit addressing by
introducing a struct nft_regs, which holds the verdict register as
well as the data registers. The verdict members are moved to a new
struct nft_verdict to allow to pull struct nft_data out of the stack.
* the next patches contain preparatory conversions of expressions and
sets to use 32 bit addressing
* the next patch introduces so far unused register conversion helpers
for parsing and dumping register numbers over netlink
* following is the real conversion to 32 bit addressing, consisting of
replacing struct nft_data in struct nft_regs by an array of u32s and
actually translating and validating the new register numbers.
* the final two patches add support for variable sized data items and
variable sized keys / data in set elements
The patches have been verified to work correctly with nft binaries using
both old and new addressing.
====================
Patrick McHardy says:
====================
netfilter: nf_tables: dynamic stateful expression instantiation
The following patches are the grand finale of my nf_tables set work,
using all the building blocks put in place by the previous patches
to support something like iptables hashlimit, but a lot more powerful.
Sets are extended to allow attaching expressions to set elements.
The dynset expression dynamically instantiates these expressions
based on a template when creating new set elements and evaluates
them for all new or updated set members.
In combination with concatenations this effectively creates state
tables for arbitrary combinations of keys, using the existing
expression types to maintain that state. Regular set GC takes care
of purging expired states.
We currently support two different stateful expressions, counter
and limit. Using limit as a template we can express the functionality
of hashlimit, but completely unrestricted in the combination of keys.
Using counter we can perform accounting for arbitrary flows.
The following examples from patch 5/5 show some possibilities.
Userspace syntax is still WIP, especially the listing of state
tables will most likely be seperated from normal set listings
and use a more structured format:
1. Limit the rate of new SSH connections per host, similar to iptables
hashlimit:
flow ip saddr timeout 60s \
limit 10/second \
accept
2. Account network traffic between each set of /24 networks:
flow ip saddr & 255.255.255.0 . ip daddr & 255.255.255.0 \
counter
3. Account traffic to each host per user:
flow skuid . ip daddr \
counter
4. Account traffic for each combination of source address and TCP flags:
flow ip saddr . tcp flags \
counter
The resulting set content after a Xmas-scan look like this:
{
192.168.122.1 . fin | psh | urg : counter packets 1001 bytes 40040,
192.168.122.1 . ack : counter packets 74 bytes 3848,
192.168.122.1 . psh | ack : counter packets 35 bytes 3144
}
In the future the "expressions attached to elements" will be extended
to also support user created non-stateful expressions to allow to
efficiently select beween a set of parameter sets, f.i. a set of log
statements with different prefixes based on the interface, which currently
require one rule each. This will most likely have to wait until the next
kernel version though.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Using a timer wheel for timewait sockets was nice ~15 years ago when
memory was expensive and machines had a single processor.
This does not scale, code is ugly and source of huge latencies
(Typically 30 ms have been seen, cpus spinning on death_lock spinlock.)
We can afford to use an extra 64 bytes per timewait sock and spread
timewait load to all cpus to have better behavior.
Tested:
On following test, /proc/sys/net/ipv4/tcp_tw_recycle is set to 1
on the target (lpaa24)
Before patch :
lpaa23:~# ./super_netperf 200 -H lpaa24 -t TCP_CC -l 60 -- -p0,0
419594
lpaa23:~# ./super_netperf 200 -H lpaa24 -t TCP_CC -l 60 -- -p0,0
437171
While test is running, we can observe 25 or even 33 ms latencies.
lpaa24:~# ping -c 1000 -i 0.02 -qn lpaa23
...
1000 packets transmitted, 1000 received, 0% packet loss, time 20601ms
rtt min/avg/max/mdev = 0.020/0.217/25.771/1.535 ms, pipe 2
lpaa24:~# ping -c 1000 -i 0.02 -qn lpaa23
...
1000 packets transmitted, 1000 received, 0% packet loss, time 20702ms
rtt min/avg/max/mdev = 0.019/0.183/33.761/1.441 ms, pipe 2
After patch :
About 90% increase of throughput :
lpaa23:~# ./super_netperf 200 -H lpaa24 -t TCP_CC -l 60 -- -p0,0
810442
lpaa23:~# ./super_netperf 200 -H lpaa24 -t TCP_CC -l 60 -- -p0,0
800992
And latencies are kept to minimal values during this load, even
if network utilization is 90% higher :
lpaa24:~# ping -c 1000 -i 0.02 -qn lpaa23
...
1000 packets transmitted, 1000 received, 0% packet loss, time 19991ms
rtt min/avg/max/mdev = 0.023/0.064/0.360/0.042 ms
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The printed values are all of type unsigned integer, therefore use
%u instead of %d. Otherwise an user can face negative values.
Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The printed values are all of type unsigned integer, therefore use
%u instead of %d. Otherwise an user can face negative values.
Fixes:
$ cat /proc/net/netfilter/nfnetlink_queue
0 29508 278 2 65531 0 2004213241 -2129885586 1
1 -27747 0 2 65531 0 0 0 1
2 -27748 0 2 65531 0 0 0 1
Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The netlink portid is an unsigned integer, use this type
also in netfilter.
Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
There's an example net/netfilter/nft_expr_template.c example file in tree that
got out of sync along time, remove it.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Patrick McHardy <kaber@trash.net>
Support instantiating stateful expressions based on a template that
are associated with dynamically created set entries. The expressions
are evaluated when adding or updating the set element.
This allows to maintain per flow state using the existing set
infrastructure and expression types, with arbitrary definitions of
a flow.
Usage is currently restricted to anonymous sets, meaning only a single
binding can exist, since the desired semantics of multiple independant
bindings haven't been defined so far.
Examples (userspace syntax is still WIP):
1. Limit the rate of new SSH connections per host, similar to iptables
hashlimit:
flow ip saddr timeout 60s \
limit 10/second \
accept
2. Account network traffic between each set of /24 networks:
flow ip saddr & 255.255.255.0 . ip daddr & 255.255.255.0 \
counter
3. Account traffic to each host per user:
flow skuid . ip daddr \
counter
4. Account traffic for each combination of source address and TCP flags:
flow ip saddr . tcp flags \
counter
The resulting set content after a Xmas-scan look like this:
{
192.168.122.1 . fin | psh | urg : counter packets 1001 bytes 40040,
192.168.122.1 . ack : counter packets 74 bytes 3848,
192.168.122.1 . psh | ack : counter packets 35 bytes 3144
}
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add a set flag to indicate that the set is used as a state table and
contains expressions for evaluation. This operation is mutually
exclusive with the mapping operation, so sets specifying both are
rejected. The lookup expression also rejects binding to state tables
since it only deals with loopup and map operations.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add a flag to mark stateful expressions.
This is used for dynamic expression instanstiation to limit the usable
expressions. Strictly speaking only the dynset expression can not be
used in order to avoid recursion, but since dynamically instantiating
non-stateful expressions will simply create an identical copy, which
behaves no differently than the original, this limits to expressions
where it actually makes sense to dynamically instantiate them.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Preparation to attach expressions to set elements: add a set extension
type to hold an expression and dump the expression information with the
set element.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add helper functions for initializing, cloning, dumping and destroying
a single expression that is not part of a rule.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch changes sets to support variable sized set element keys / data
up to 64 bytes each by using variable sized set extensions. This allows
to use concatenations with bigger data items suchs as IPv6 addresses.
As a side effect, small keys/data now don't require the full 16 bytes
of struct nft_data anymore but just the space they need.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add a size argument to nft_data_init() and pass in the available space.
This will be used by the following patches to support variable sized
set element data.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Switch the nf_tables registers from 128 bit addressing to 32 bit
addressing to support so called concatenations, where multiple values
can be concatenated over multiple registers for O(1) exact matches of
multiple dimensions using sets.
The old register values are mapped to areas of 128 bits for compatibility.
When dumping register numbers, values are expressed using the old values
if they refer to the beginning of a 128 bit area for compatibility.
To support concatenations, register loads of less than a full 32 bit
value need to be padded. This mainly affects the payload and exthdr
expressions, which both unconditionally zero the last word before
copying the data.
Userspace fully passes the testsuite using both old and new register
addressing.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add helper functions to parse and dump register values in netlink attributes.
These helpers will later be changed to take care of translation between the
old 128 bit and the new 32 bit register numbers.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Simple conversion to use u32 pointers to the beginning of the data
area to keep follow up patches smaller.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Only needlessly complicates things due to requiring specific argument
types. Use memcmp directly.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Simple conversion to use u32 pointers to the beginning of the registers
to keep follow up patches smaller.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Replace the array of registers passed to expressions by a struct nft_regs,
containing the verdict as a seperate member, which aliases to the
NFT_REG_VERDICT register.
This is needed to seperate the verdict from the data registers completely,
so their size can be changed.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Change nft_validate_input_register() to not only validate the input
register number, but also the length of the load, and rename it to
nft_validate_register_load() to reflect that change.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
All users of nft_validate_register_store() first invoke
nft_validate_output_register(). There is in fact no use for using it
on its own, so simplify the code by folding the functionality into
nft_validate_register_store() and kill it.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
In preparation of validating the length of a register store, use
nft_validate_register_store() in nft_lookup instead of open coding the
validation.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The existing name is ambiguous, data is loaded as well when we read from
a register. Rename to nft_validate_register_store() for clarity and
consistency with the upcoming patch to introduce its counterpart,
nft_validate_register_load().
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
For values spanning multiple registers, we need to validate that enough
space is available from the destination register onwards. Add a len
argument to nft_validate_data_load() and consolidate the existing length
validations in preparation of that.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Pablo Neira Ayuso says:
====================
Netfilter updates for net-next
The following patchset contains Netfilter updates for your net-next tree.
They are:
* nf_tables set timeout infrastructure from Patrick Mchardy.
1) Add support for set timeout support.
2) Add support for set element timeouts using the new set extension
infrastructure.
4) Add garbage collection helper functions to get rid of stale elements.
Elements are accumulated in a batch that are asynchronously released
via RCU when the batch is full.
5) Add garbage collection synchronization helpers. This introduces a new
element busy bit to address concurrent access from the netlink API and the
garbage collector.
5) Add timeout support for the nft_hash set implementation. The garbage
collector peridically checks for stale elements from the workqueue.
* iptables/nftables cgroup fixes:
6) Ignore non full-socket objects from the input path, otherwise cgroup
match may crash, from Daniel Borkmann.
7) Fix cgroup in nf_tables.
8) Save some cycles from xt_socket by skipping packet header parsing when
skb->sk is already set because of early demux. Also from Daniel.
* br_netfilter updates from Florian Westphal.
9) Save frag_max_size and restore it from the forward path too.
10) Use a per-cpu area to restore the original source MAC address when traffic
is DNAT'ed.
11) Add helper functions to access physical devices.
12) Use these new physdev helper function from xt_physdev.
13) Add another nf_bridge_info_get() helper function to fetch the br_netfilter
state information.
14) Annotate original layer 2 protocol number in nf_bridge info, instead of
using kludgy flags.
15) Also annotate the pkttype mangling when the packet travels back and forth
from the IP to the bridge layer, instead of using a flag.
* More nf_tables set enhancement from Patrick:
16) Fix possible usage of set variant that doesn't support timeouts.
17) Avoid spurious "set is full" errors from Netlink API when there are pending
stale elements scheduled to be released.
18) Restrict loop checks to set maps.
19) Add support for dynamic set updates from the packet path.
20) Add support to store optional user data (eg. comments) per set element.
BTW, I have also pulled net-next into nf-next to anticipate the conflict
resolution between your okfn() signature changes and Florian's br_netfilter
updates.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
More recent GCC warns about two kinds of switch statement uses:
1) Switching on an enumeration, but not having an explicit case
statement for all members of the enumeration. To show the
compiler this is intentional, we simply add a default case
with nothing more than a break statement.
2) Switching on a boolean value. I think this warning is dumb
but nevertheless you get it wholesale with -Wswitch.
This patch cures all such warnings in netfilter.
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add an userdata set extension and allow the user to attach arbitrary
data to set elements. This is intended to hold TLV encoded data like
comments or DNS annotations that have no meaning to the kernel.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add a new "dynset" expression for dynamic set updates.
A new set op ->update() is added which, for non existant elements,
invokes an initialization callback and inserts the new element.
For both new or existing elements the extenstion pointer is returned
to the caller to optionally perform timer updates or other actions.
Element removal is not supported so far, however that seems to be a
rather exotic need and can be added later on.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Currently a set binding is assumed to be related to a lookup and, in
case of maps, a data load.
In order to use bindings for set updates, the loop detection checks
must be restricted to map operations only. Add a flags member to the
binding struct to hold the set "action" flags such as NFT_SET_MAP,
and perform loop detection based on these.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Use atomic operations for the element count to avoid races with async
updates.
To properly handle the transactional semantics during netlink updates,
deleted but not yet committed elements are accounted for seperately and
are treated as being already removed. This means for the duration of
a netlink transaction, the limit might be exceeded by the amount of
elements deleted. Set implementations must be prepared to handle this.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The NFT_SET_TIMEOUT flag is ignore in nft_select_set_ops, which may
lead to selection of a set implementation that doesn't actually
support timeouts.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
right now we store this in the nf_bridge_info struct, accessible
via skb->nf_bridge. This patch prepares removal of this pointer from skb:
Instead of using skb->nf_bridge->x, we use helpers to obtain the in/out
device (or ifindexes).
Followup patches to netfilter will then allow nf_bridge_info to be
obtained by a call into the br_netfilter core, rather than keeping a
pointer to it in sk_buff.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Currently in xt_socket, we take advantage of early demuxed sockets
since commit 00028aa370 ("netfilter: xt_socket: use IP early demux")
in order to avoid a second socket lookup in the fast path, but we
only make partial use of this:
We still unnecessarily parse headers, extract proto, {s,d}addr and
{s,d}ports from the skb data, accessing possible conntrack information,
etc even though we were not even calling into the socket lookup via
xt_socket_get_sock_{v4,v6}() due to skb->sk hit, meaning those cycles
can be spared.
After this patch, we only proceed the slower, manual lookup path
when we have a skb->sk miss, thus time to match verdict for early
demuxed sockets will improve further, which might be i.e. interesting
for use cases such as mentioned in 681f130f39 ("netfilter: xt_socket:
add XT_SOCKET_NOWILDCARD flag").
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
On the output paths in particular, we have to sometimes deal with two
socket contexts. First, and usually skb->sk, is the local socket that
generated the frame.
And second, is potentially the socket used to control a tunneling
socket, such as one the encapsulates using UDP.
We do not want to disassociate skb->sk when encapsulating in order
to fix this, because that would break socket memory accounting.
The most extreme case where this can cause huge problems is an
AF_PACKET socket transmitting over a vxlan device. We hit code
paths doing checks that assume they are dealing with an ipv4
socket, but are actually operating upon the AF_PACKET one.
Signed-off-by: David S. Miller <davem@davemloft.net>
It is currently always set to NULL, but nf_queue is adjusted to be
prepared for it being set to a real socket by taking and releasing a
reference to that socket when necessary.
Signed-off-by: David S. Miller <davem@davemloft.net>
That way we don't have to reinstantiate another nf_hook_state
on the stack of the nf_reinject() path.
Signed-off-by: David S. Miller <davem@davemloft.net>
Instead of passing a large number of arguments down into the nf_hook()
entry points, create a structure which carries this state down through
the hook processing layers.
This makes is so that if we want to change the types or signatures of
any of these pieces of state, there are less places that need to be
changed.
Signed-off-by: David S. Miller <davem@davemloft.net>
We have to stop iterating on the rule expressions if the cgroup
mismatches. Moreover, make sure a non-full socket from the input path
leads us to a crash.
Fixes: ce67417 ("netfilter: nft_meta: add cgroup support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
While originally only being intended for outgoing traffic, commit
a00e76349f ("netfilter: x_tables: allow to use cgroup match for
LOCAL_IN nf hooks") enabled xt_cgroups for the NF_INET_LOCAL_IN hook
as well, in order to allow for nfacct accounting.
Besides being currently limited to early demuxes only, commit
a00e76349f forgot to add a check if we deal with full sockets,
i.e. in this case not with time wait sockets. TCP time wait sockets
do not have the same memory layout as full sockets, a lower memory
footprint and consequently also don't have a sk_classid member;
probing for sk_classid member there could potentially lead to a
crash.
Fixes: a00e76349f ("netfilter: x_tables: allow to use cgroup match for LOCAL_IN nf hooks")
Cc: Alexey Perevalov <a.perevalov@samsung.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add support for element timeouts to nft_hash. The lookup and walking
functions are changed to ignore timed out elements, a periodic garbage
collection task cleans out expired entries.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
GC is expected to happen asynchrously to the netlink interface. In the
netlink path, both insertion and removal of elements consist of two
steps, insertion followed by activation or deactivation followed by
removal, during which the element must not be freed by GC.
The synchronization helpers use an unused bit in the genmask field to
atomically mark an element as "busy", meaning it is either currently
being handled through the netlink API or by GC.
Elements being processed by GC will never survive, netlink will simply
ignore them. Elements being currently processed through netlink will be
skipped by GC and reprocessed during the next run.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add helpers for GC batch destruction: since element destruction needs
a RCU grace period for all set implementations, add some helper functions
for asynchronous batch destruction. Elements are collected in a batch
structure, which is asynchronously released using RCU once its full.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add API support for set element timeouts. Elements can have a individual
timeout value specified, overriding the sets' default.
Two new extension types are used for timeouts - the timeout value and
the expiration time. The timeout value only exists if it differs from
the default value.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
