Fix typos and add the following to the scripts/spelling.txt:
aligment||alignment
I did not touch the "N_BYTE_ALIGMENT" macro in
drivers/net/wireless/realtek/rtlwifi/wifi.h to avoid unpredictable
impact.
I fixed "_aligment_handler" in arch/openrisc/kernel/entry.S because
it is surrounded by #if 0 ... #endif. It is surely safe and I
confirmed "_alignment_handler" is correct.
I also fixed the "controler" I found in the same hunk in
arch/openrisc/kernel/head.S.
Link: http://lkml.kernel.org/r/1481573103-11329-8-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix typos and add the following to the scripts/spelling.txt:
an user||a user
an userspace||a userspace
I also added "userspace" to the list since it is a common word in Linux.
I found some instances for "an userfaultfd", but I did not add it to the
list. I felt it is endless to find words that start with "user" such as
"userland" etc., so must draw a line somewhere.
Link: http://lkml.kernel.org/r/1481573103-11329-4-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pablo Neira Ayuso says:
====================
Netfilter fixes for net
The following patchset contains Netfilter fixes for your net tree,
they are:
1) Revisit warning logic when not applying default helper assignment.
Jiri Kosina considers we are breaking existing setups and not warning
our users accordinly now that automatic helper assignment has been
turned off by default. So let's make him happy by spotting the warning
by when we find a helper but we cannot attach, instead of warning on the
former deprecated behaviour. Patch from Jiri Kosina.
2) Two patches to fix regression in ctnetlink interfaces with
nfnetlink_queue. Specifically, perform more relaxed in CTA_STATUS
and do not bail out if CTA_HELP indicates the same helper that we
already have. Patches from Kevin Cernekee.
3) A couple of bugfixes for ipset via Jozsef Kadlecsik. Due to wrong
index logic in hash set types and null pointer exception in the
list:set type.
4) hashlimit bails out with correct userspace parameters due to wrong
arithmetics in the code that avoids "divide by zero" when
transforming the userspace timing in milliseconds to token credits.
Patch from Alban Browaeys.
5) Fix incorrect NFQA_VLAN_MAX definition, patch from
Ken-ichirou MATSUZAWA.
6) Don't not declare nfnetlink batch error list as static, since this
may be used by several subsystems at the same time. Patch from
Liping Zhang.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Jozsef Kadlecsik says:
====================
ipset patches for nf
Please apply the next patches for ipset in your nf branch.
Both patches should go into the stable kernel branches as well,
because these are important bugfixes:
* Sometimes valid entries in hash:* types of sets were evicted
due to a typo in an index. The wrong evictions happen when
entries are deleted from the set and the bucket is shrinked.
Bug was reported by Eric Ewanco and the patch fixes
netfilter bugzilla id #1119.
* Fixing of a null pointer exception when someone wants to add an
entry to an empty list type of set and specifies an add before/after
option. The fix is from Vishwanath Pai.
====================
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Otherwise, different subsys will race to access the err_list, with holding
the different nfnl_lock(subsys_id).
But this will not happen now, since ->call_batch is only implemented by
nftables, so the err_list is protected by nfnl_lock(NFNL_SUBSYS_NFTABLES).
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diving the divider by the multiplier before applying to the input.
When this would "divide by zero", divide the multiplier by the divider
first then multiply the input by this value.
Currently user2creds outputs zero when input value is bigger than the
number of slices and lower than scale.
This as then user input is applied an integer divide operation to
a number greater than itself (scale).
That rounds up to zero, then we multiply zero by the credits slice size.
iptables -t filter -I INPUT --protocol tcp --match hashlimit
--hashlimit 40/second --hashlimit-burst 20 --hashlimit-mode srcip
--hashlimit-name syn-flood --jump RETURN
thus trigger the overflow detection code:
xt_hashlimit: overflow, try lower: 25000/20
(25000 as hashlimit avg and 20 the burst)
Here:
134217 slices of (HZ * CREDITS_PER_JIFFY) size.
500000 is user input value
1000000 is XT_HASHLIMIT_SCALE_v2
gives: 0 as user2creds output
Setting burst to "1" typically solve the issue ...
but setting it to "40" does too !
This is on 32bit arch calling into revision 2 of hashlimit.
Signed-off-by: Alban Browaeys <alban.browaeys@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
If we use before/after to add an element to an empty list it will cause
a kernel panic.
$> cat crash.restore
create a hash:ip
create b hash:ip
create test list:set timeout 5 size 4
add test b before a
$> ipset -R < crash.restore
Executing the above will crash the kernel.
Signed-off-by: Vishwanath Pai <vpai@akamai.com>
Reviewed-by: Josh Hunt <johunt@akamai.com>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Wrong index was used and therefore when shrinking a hash bucket at
deleting an entry, valid entries could be evicted as well.
Thanks to Eric Ewanco for the thorough bugreport.
Fixes netfilter bugzilla #1119
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
This new attribute allows us to uniquely identify a rule in transaction.
Robots may trigger an insertion followed by deletion in a batch, in that
scenario we still don't have a public rule handle that we can use to
delete the rule. This is similar to the NFTA_SET_ID attribute that
allows us to refer to an anonymous set from a batch.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch implements the check generation id as provided by nfnetlink.
This allows us to reject ruleset updates against stale baseline, so
userspace can retry update with a fresh ruleset cache.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch allows userspace to specify the generation ID that has been
used to build an incremental batch update.
If userspace specifies the generation ID in the batch message as
attribute, then nfnetlink compares it to the current generation ID so
you make sure that you work against the right baseline. Otherwise, bail
out with ERESTART so userspace knows that its changeset is stale and
needs to respin. Userspace can do this transparently at the cost of
taking slightly more time to refresh caches and rework the changeset.
This check is optional, if there is no NFNL_BATCH_GENID attribute in the
batch begin message, then no check is performed.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Because nf_ct_expect_insert() always succeeds now, its return value can
be just void instead of int. And remove code that checks for its return
value.
Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
timer_del() followed by timer_add() can be replaced by
mod_timer_pending().
Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch implements the kernel side of the TCP option patch.
Signed-off-by: Manuel Messner <mm@skelett.io>
Reviewed-by: Florian Westphal <fw@strlen.de>
Acked-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
zones allow tracking multiple connections sharing identical tuples,
this is needed e.g. when tracking distinct vlans with overlapping ip
addresses (conntrack is l2 agnostic).
Thus the zone has to be set before the packet is picked up by the
connection tracker. This is done by means of 'conntrack templates' which
are conntrack structures used solely to pass this info from one netfilter
hook to the next.
The iptables CT target instantiates these connection tracking templates
once per rule, i.e. the template is fixed/tied to particular zone, can
be read-only and therefore be re-used by as many skbs simultaneously as
needed.
We can't follow this model because we want to take the zone id from
an sreg at rule eval time so we could e.g. fill in the zone id from
the packets vlan id or a e.g. nftables key : value maps.
To avoid cost of per packet alloc/free of the template, use a percpu
template 'scratch' object and use the refcount to detect the (unlikely)
case where the template is still attached to another skb (i.e., previous
skb was nfqueued ...).
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Next patch will add ZONE_ID set support which will need similar
error unwind (put operation) as conntrack labels.
Prepare for this: remove the 'label_got' boolean in favor
of a switch statement that can be extended in next patch.
As we already have that in the set_destroy function place that in
a separate function and call it from the set init function.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Just like with counters the direction attribute is optional.
We set priv->dir to MAX unconditionally to avoid duplicating the assignment
for all keys with optional direction.
For keys where direction is mandatory, existing code already returns
an error.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This patch adds a new bitmap set type. This bitmap uses two bits to
represent one element. These two bits determine the element state in the
current and the future generation that fits into the nf_tables commit
protocol. When dumping elements back to userspace, the two bits are
expanded into a struct nft_set_ext object.
If no NFTA_SET_DESC_SIZE is specified, the existing automatic set
backend selection prefers bitmap over hash in case of keys whose size is
<= 16 bit. If the set size is know, the bitmap set type is selected if
with 16 bit kets and more than 390 elements in the set, otherwise the
hash table set implementation is used.
For 8 bit keys, the bitmap consumes 66 bytes. For 16 bit keys, the
bitmap takes 16388 bytes.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The space notation allows us to classify the set backend implementation
based on the amount of required memory. This provides an order of the
set representation scalability in terms of memory. The size field is
still left in place so use this if the userspace provides no explicit
number of elements, so we cannot calculate the real memory that this set
needs. This also helps us break ties in the set backend selection
routine, eg. two backend implementations provide the same performance.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Use lookup as field name instead, to prepare the introduction of the
memory class in a follow up patch.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This provides context to walk callback iterator, thus, we know if the
walk happens from the set flush path. This is required by the new bitmap
set type coming in a follow up patch which has no real struct
nft_set_ext, so it has to allocate it based on the two bit compact
element representation.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Although semantics are similar to deactivate() with no implicit element
lookup, this is only called from the set flush path, so better rename
this to flush().
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
If NFT_EXTHDR_F_PRESENT is set, exthdr will not copy any header field
data into *dest, but instead set it to 1 if the header is found and 0
otherwise.
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Prior to Linux 4.4, it was usually harmless to send a CTA_HELP attribute
containing the name of the current helper. That is no longer the case:
as of Linux 4.4, if ctnetlink_change_helper() returns an error from
the ct->master check, processing of the request will fail, skipping the
NFQA_EXP attribute (if present).
This patch changes the behavior to improve compatibility with user
programs that expect the kernel interface to work the way it did prior
to Linux 4.4. If a user program specifies CTA_HELP but the argument
matches the current conntrack helper name, ignore it instead of generating
an error.
Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The libnetfilter_conntrack userland library always sets IPS_CONFIRMED
when building a CTA_STATUS attribute. If this toggles the bit from
0->1, the parser will return an error. On Linux 4.4+ this will cause any
NFQA_EXP attribute in the packet to be ignored. This breaks conntrackd's
userland helpers because they operate on unconfirmed connections.
Instead of returning -EBUSY if the user program asks to modify an
unchangeable bit, simply ignore the change.
Also, fix the logic so that user programs are allowed to clear
the bits that they are allowed to change.
Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Commit 3bb398d925 ("netfilter: nf_ct_helper: disable automatic helper
assignment") is causing behavior regressions in firewalls, as traffic
handled by conntrack helpers is now by default not passed through even
though it was before due to missing CT targets (which were not necessary
before this commit).
The default had to be switched off due to security reasons [1] [2] and
therefore should stay the way it is, but let's be friendly to firewall
admins and issue a warning the first time we're in situation where packet
would be likely passed through with the old default but we're likely going
to drop it on the floor now.
Rewrite the code a little bit as suggested by Linus, so that we avoid
spaghettiing the code even more -- namely the whole decision making
process regarding helper selection (either automatic or not) is being
separated, so that the whole logic can be simplified and code (condition)
duplication reduced.
[1] https://cansecwest.com/csw12/conntrack-attack.pdf
[2] https://home.regit.org/netfilter-en/secure-use-of-helpers/
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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:
1) Stash ctinfo 3-bit field into pointer to nf_conntrack object from
sk_buff so we only access one single cacheline in the conntrack
hotpath. Patchset from Florian Westphal.
2) Don't leak pointer to internal structures when exporting x_tables
ruleset back to userspace, from Willem DeBruijn. This includes new
helper functions to copy data to userspace such as xt_data_to_user()
as well as conversions of our ip_tables, ip6_tables and arp_tables
clients to use it. Not surprinsingly, ebtables requires an ad-hoc
update. There is also a new field in x_tables extensions to indicate
the amount of bytes that we copy to userspace.
3) Add nf_log_all_netns sysctl: This new knob allows you to enable
logging via nf_log infrastructure for all existing netnamespaces.
Given the effort to provide pernet syslog has been discontinued,
let's provide a way to restore logging using netfilter kernel logging
facilities in trusted environments. Patch from Michal Kubecek.
4) Validate SCTP checksum from conntrack helper, from Davide Caratti.
5) Merge UDPlite conntrack and NAT helpers into UDP, this was mostly
a copy&paste from the original helper, from Florian Westphal.
6) Reset netfilter state when duplicating packets, also from Florian.
7) Remove unnecessary check for broadcast in IPv6 in pkttype match and
nft_meta, from Liping Zhang.
8) Add missing code to deal with loopback packets from nft_meta when
used by the netdev family, also from Liping.
9) Several cleanups on nf_tables, one to remove unnecessary check from
the netlink control plane path to add table, set and stateful objects
and code consolidation when unregister chain hooks, from Gao Feng.
10) Fix harmless reference counter underflow in IPVS that, however,
results in problems with the introduction of the new refcount_t
type, from David Windsor.
11) Enable LIBCRC32C from nf_ct_sctp instead of nf_nat_sctp,
from Davide Caratti.
12) Missing documentation on nf_tables uapi header, from Liping Zhang.
13) Use rb_entry() helper in xt_connlimit, from Geliang Tang.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 69b34fb996 ("netfilter: xt_LOG: add net namespace support for
xt_LOG") disabled logging packets using the LOG target from non-init
namespaces. The motivation was to prevent containers from flooding
kernel log of the host. The plan was to keep it that way until syslog
namespace implementation allows containers to log in a safe way.
However, the work on syslog namespace seems to have hit a dead end
somewhere in 2013 and there are users who want to use xt_LOG in all
network namespaces. This patch allows to do so by setting
/proc/sys/net/netfilter/nf_log_all_netns
to a nonzero value. This sysctl is only accessible from init_net so that
one cannot switch the behaviour from inside a container.
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Currently, the ip_vs_dest cache frees ip_vs_dest objects when their
reference count becomes < 0. Aside from not being semantically sound,
this is problematic for the new type refcount_t, which will be introduced
shortly in a separate patch. refcount_t is the new kernel type for
holding reference counts, and provides overflow protection and a
constrained interface relative to atomic_t (the type currently being
used for kernel reference counts).
Per Julian Anastasov: "The problem is that dest_trash currently holds
deleted dests (unlinked from RCU lists) with refcnt=0." Changing
dest_trash to hold dest with refcnt=1 will allow us to free ip_vs_dest
structs when their refcnt=0, in ip_vs_dest_put_and_free().
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
After this change conntrack operations (lookup, creation, matching from
ruleset) only access one instead of two sk_buff cache lines.
This works for normal conntracks because those are allocated from a slab
that guarantees hw cacheline or 8byte alignment (whatever is larger)
so the 3 bits needed for ctinfo won't overlap with nf_conn addresses.
Template allocation now does manual address alignment (see previous change)
on arches that don't have sufficent kmalloc min alignment.
Some spots intentionally use skb->_nfct instead of skb_nfct() helpers,
this is to avoid undoing the skb_nfct() use when we remove untracked
conntrack object in the future.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The next change will merge skb->nfct pointer and skb->nfctinfo
status bits into single skb->_nfct (unsigned long) area.
For this to work nf_conn addresses must always be aligned at least on
an 8 byte boundary since we will need the lower 3bits to store nfctinfo.
Conntrack templates are allocated via kmalloc.
kbuild test robot reported
BUILD_BUG_ON failed: NFCT_INFOMASK >= ARCH_KMALLOC_MINALIGN
on v1 of this patchset, so not all platforms meet this requirement.
Do manual alignment if needed, the alignment offset is stored in the
nf_conn entry protocol area. This works because templates are not
handed off to L4 protocol trackers.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add a helper to assign a nf_conn entry and the ctinfo bits to an sk_buff.
This avoids changing code in followup patch that merges skb->nfct and
skb->nfctinfo into skb->_nfct.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Followup patch renames skb->nfct and changes its type so add a helper to
avoid intrusive rename change later.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Next patch makes direct skb->nfct access illegal, reduce noise
in next patch by using accessors we already have.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
It is never accessed for reading and the only places that write to it
are the icmp(6) handlers, which also set skb->nfct (and skb->nfctinfo).
The conntrack core specifically checks for attached skb->nfct after
->error() invocation and returns early in this case.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
If something fails in nf_tables_table_enable(), it unregisters the
chains. But the rollback code is the same as nf_tables_table_disable()
almostly, except there is one counter check. Now create one wrapper
function to eliminate the duplicated codes.
Signed-off-by: Feng <fgao@ikuai8.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add missing set->ndeact update on each deactivated element from the set
flush path. Otherwise, sets with fixed size break after flush since
accounting breaks.
# nft add set x y { type ipv4_addr\; size 2\; }
# nft add element x y { 1.1.1.1 }
# nft add element x y { 1.1.1.2 }
# nft flush set x y
# nft add element x y { 1.1.1.1 }
<cmdline>:1:1-28: Error: Could not process rule: Too many open files in system
Fixes: 8411b6442e ("netfilter: nf_tables: support for set flushing")
Reported-by: Elise Lennion <elise.lennion@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
If the element exists and no NLM_F_EXCL is specified, do not bump
set->nelems, otherwise we leak one set element slot. This problem
amplifies if the set is full since the abort path always decrements the
counter for the -ENFILE case too, giving one spare extra slot.
Fix this by moving set->nelems update to nft_add_set_elem() after
successful element insertion. Moreover, remove the element if the set is
full so there is no need to rely on the abort path to undo things
anymore.
Fixes: c016c7e45d ("netfilter: nf_tables: honor NLM_F_EXCL flag in set element insertion")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
First, log prefix will be truncated to NF_LOG_PREFIXLEN-1, i.e. 127,
at nf_log_packet(), so the extra part is useless.
Second, after adding a log rule with a very very long prefix, we will
fail to dump the nft rules after this _special_ one, but acctually,
they do exist. For example:
# name_65000=$(printf "%0.sQ" {1..65000})
# nft add rule filter output log prefix "$name_65000"
# nft add rule filter output counter
# nft add rule filter output counter
# nft list chain filter output
table ip filter {
chain output {
type filter hook output priority 0; policy accept;
}
}
So now, restrict the log prefix length to NF_LOG_PREFIXLEN-1.
Fixes: 96518518cc ("netfilter: add nftables")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add net.ipv4.ip_unprivileged_port_start, which is a per namespace sysctl
that denotes the first unprivileged inet port in the namespace. To
disable all privileged ports set this to zero. It also checks for
overlap with the local port range. The privileged and local range may
not overlap.
The use case for this change is to allow containerized processes to bind
to priviliged ports, but prevent them from ever being allowed to modify
their container's network configuration. The latter is accomplished by
ensuring that the network namespace is not a child of the user
namespace. This modification was needed to allow the container manager
to disable a namespace's priviliged port restrictions without exposing
control of the network namespace to processes in the user namespace.
Signed-off-by: Krister Johansen <kjlx@templeofstupid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, if the user add a stateful object with the name size exceed
NFT_OBJ_MAXNAMELEN - 1 (i.e. 31), we truncate it down to 31 silently.
This is not friendly, furthermore, this will cause duplicated stateful
objects when the first 31 characters of the name is same. So limit the
stateful object's name size to NFT_OBJ_MAXNAMELEN - 1.
After apply this patch, error message will be printed out like this:
# name_32=$(printf "%0.sQ" {1..32})
# nft add counter filter $name_32
<cmdline>:1:1-52: Error: Could not process rule: Numerical result out
of range
add counter filter QQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQ
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Also this patch cleans up the codes which missing the name size limit
validation in nftables.
Fixes: e50092404c ("netfilter: nf_tables: add stateful objects")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This further refines the changes made to conntrack gc_worker in
commit e0df8cae6c ("netfilter: conntrack: refine gc worker heuristics").
The main idea of that change was to reduce the scan interval when evictions
take place.
However, on the reporters' setup, there are 1-2 million conntrack entries
in total and roughly 8k new (and closing) connections per second.
In this case we'll always evict at least one entry per gc cycle and scan
interval is always at 1 jiffy because of this test:
} else if (expired_count) {
gc_work->next_gc_run /= 2U;
next_run = msecs_to_jiffies(1);
being true almost all the time.
Given we scan ~10k entries per run its clearly wrong to reduce interval
based on nonzero eviction count, it will only waste cpu cycles since a vast
majorities of conntracks are not timed out.
Thus only look at the ratio (scanned entries vs. evicted entries) to make
a decision on whether to reduce or not.
Because evictor is supposed to only kick in when system turns idle after
a busy period, pick a high ratio -- this makes it 50%. We thus keep
the idea of increasing scan rate when its likely that table contains many
expired entries.
In order to not let timed-out entries hang around for too long
(important when using event logging, in which case we want to timely
destroy events), we now scan the full table within at most
GC_MAX_SCAN_JIFFIES (16 seconds) even in worst-case scenario where all
timed-out entries sit in same slot.
I tested this with a vm under synflood (with
sysctl net.netfilter.nf_conntrack_tcp_timeout_syn_recv=3).
While flood is ongoing, interval now stays at its max rate
(GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV -> 125ms).
With feedback from Nicolas Dichtel.
Reported-by: Denys Fedoryshchenko <nuclearcat@nuclearcat.com>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Fixes: b87a2f9199 ("netfilter: conntrack: add gc worker to remove timed-out entries")
Signed-off-by: Florian Westphal <fw@strlen.de>
Tested-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Tested-by: Denys Fedoryshchenko <nuclearcat@nuclearcat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Instead of breaking loop and instant resched, don't bother checking
this in first place (the loop calls cond_resched for every bucket anyway).
Suggested-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
