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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>
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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>
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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>
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Set elements are the last object type not supporting transaction support.
Implement similar to the existing rule transactions:
The global transaction counter keeps track of two generations, current
and next. Each element contains a bitmask specifying in which generations
it is inactive.
New elements start out as inactive in the current generation and active
in the next. On commit, the previous next generation becomes the current
generation and the element becomes active. The bitmask is then cleared
to indicate that the element is active in all future generations. If the
transaction is aborted, the element is removed from the set before it
becomes active.
When removing an element, it gets marked as inactive in the next generation.
On commit the next generation becomes active and the therefor the element
inactive. It is then taken out of then set and released. On abort, the
element is marked as active for the next generation again.
Lookups ignore elements not active in the current generation.
The current set types (hash/rbtree) both use a field in the extension area
to store the generation mask. This (currently) does not require any
additional memory since we have some free space in there.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Return the extension area from the ->lookup() function to allow to
consolidate common actions.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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With the conversion to set extensions, it is now possible to consolidate
the different set element destruction functions.
The set implementations' ->remove() functions are changed to only take
the element out of their internal data structures. Elements will be freed
in a batched fashion after the global transaction's completion RCU grace
period.
This reduces the amount of grace periods required for nft_hash from N
to zero additional ones, additionally this guarantees that the set
elements' extensions of all implementations can be used under RCU
protection.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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The set implementations' private struct will only contain the elements
needed to maintain the search structure, all other elements are moved
to the set extensions.
Element allocation and initialization is performed centrally by
nf_tables_api instead of by the different set implementations'
->insert() functions. A new "elemsize" member in the set ops specifies
the amount of memory to reserve for internal usage. Destruction
will also be moved out of the set implementations by a following patch.
Except for element allocation, the patch is a simple conversion to
using data from the extension area.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Fix a race condition and unnecessary locking:
* the root rb_node must only be accessed under the lock in nft_rbtree_lookup()
* the lock is not needed in lookup functions in netlink context
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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The sets are released from the rcu callback, after the rule is removed
from the chain list, which implies that nfnetlink cannot update the
rbtree and no packets are walking on the set anymore. Thus, we can get
rid of the spinlock in the set destroy path there.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Reviewied-by: Thomas Graf <tgraf@suug.ch>
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There's no rbtree rcu version yet, so let's fall back on the spinlock
to protect the concurrent access of this structure both from user
(to update the set content) and kernel-space (in the packet path).
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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The current set selection simply choses the first set type that provides
the requested features, which always results in the rbtree being chosen
by virtue of being the first set in the list.
What we actually want to do is choose the implementation that can provide
the requested features and is optimal from either a performance or memory
perspective depending on the characteristics of the elements and the
preferences specified by the user.
The elements are not known when creating a set. Even if we would provide
them for anonymous (literal) sets, we'd still have standalone sets where
the elements are not known in advance. We therefore need an abstract
description of the data charcteristics.
The kernel already knows the size of the key, this patch starts by
introducing a nested set description which so far contains only the maximum
amount of elements. Based on this the set implementations are changed to
provide an estimate of the required amount of memory and the lookup
complexity class.
The set ops have a new callback ->estimate() that is invoked during set
selection. It receives a structure containing the attributes known to the
kernel and is supposed to populate a struct nft_set_estimate with the
complexity class and, in case the size is known, the complete amount of
memory required, or the amount of memory required per element otherwise.
Based on the policy specified by the user (performance/memory, defaulting
to performance) the kernel will then select the best suited implementation.
Even if the set implementation would allow to add more than the specified
maximum amount of elements, they are enforced since new implementations
might not be able to add more than maximum based on which they were
selected.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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This patch fixes several things which related to the handling of
end interval elements:
* Chain use underflow with intervals and map: If you add a rule
using intervals+map that introduces a loop, the error path of the
rbtree set decrements the chain refcount for each side of the
interval, leading to a chain use counter underflow.
* Don't copy the data part of the end interval element since, this
area is uninitialized and this confuses the loop detection code.
* Don't allocate room for the data part of end interval elements
since this is unused.
So, after this patch the idea is that end interval elements don't
have a data part.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Patrick McHardy <kaber@trash.net>
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This patch adds the new netlink API for maintaining nf_tables sets
independently of the ruleset. The API supports the following operations:
- creation of sets
- deletion of sets
- querying of specific sets
- dumping of all sets
- addition of set elements
- removal of set elements
- dumping of all set elements
Sets are identified by name, each table defines an individual namespace.
The name of a set may be allocated automatically, this is mostly useful
in combination with the NFT_SET_ANONYMOUS flag, which destroys a set
automatically once the last reference has been released.
Sets can be marked constant, meaning they're not allowed to change while
linked to a rule. This allows to perform lockless operation for set
types that would otherwise require locking.
Additionally, if the implementation supports it, sets can (as before) be
used as maps, associating a data value with each key (or range), by
specifying the NFT_SET_MAP flag and can be used for interval queries by
specifying the NFT_SET_INTERVAL flag.
Set elements are added and removed incrementally. All element operations
support batching, reducing netlink message and set lookup overhead.
The old "set" and "hash" expressions are replaced by a generic "lookup"
expression, which binds to the specified set. Userspace is not aware
of the actual set implementation used by the kernel anymore, all
configuration options are generic.
Currently the implementation selection logic is largely missing and the
kernel will simply use the first registered implementation supporting the
requested operation. Eventually, the plan is to have userspace supply a
description of the data characteristics and select the implementation
based on expected performance and memory use.
This patch includes the new 'lookup' expression to look up for element
matching in the set.
This patch includes kernel-doc descriptions for this set API and it
also includes the following fixes.
From Patrick McHardy:
* netfilter: nf_tables: fix set element data type in dumps
* netfilter: nf_tables: fix indentation of struct nft_set_elem comments
* netfilter: nf_tables: fix oops in nft_validate_data_load()
* netfilter: nf_tables: fix oops while listing sets of built-in tables
* netfilter: nf_tables: destroy anonymous sets immediately if binding fails
* netfilter: nf_tables: propagate context to set iter callback
* netfilter: nf_tables: add loop detection
From Pablo Neira Ayuso:
* netfilter: nf_tables: allow to dump all existing sets
* netfilter: nf_tables: fix wrong type for flags variable in newelem
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Patrick McHardy
Pablo Neira Ayuso