linux-toradex.git/Documentation/networking/nf_conntrack-sysctl.rst, branch v5.18-rc5

Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf

2021-09-03T23:20:37+00:00

Pablo Neira Ayuso says:

====================
Netfilter fixes for net

1) Protect nft_ct template with global mutex, from Pavel Skripkin.

2) Two recent commits switched inet rt and nexthop exception hashes
   from jhash to siphash. If those two spots are problematic then
   conntrack is affected as well, so switch voer to siphash too.
   While at it, add a hard upper limit on chain lengths and reject
   insertion if this is hit. Patches from Florian Westphal.

3) Fix use-after-scope in nf_socket_ipv6 reported by KASAN,
   from Benjamin Hesmans.

* git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf:
  netfilter: socket: icmp6: fix use-after-scope
  netfilter: refuse insertion if chain has grown too large
  netfilter: conntrack: switch to siphash
  netfilter: conntrack: sanitize table size default settings
  netfilter: nft_ct: protect nft_ct_pcpu_template_refcnt with mutex
====================

Link: https://lore.kernel.org/r/20210903163020.13741-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski

netfilter: conntrack: sanitize table size default settings

2021-08-30T09:49:54+00:00

conntrack has two distinct table size settings:
nf_conntrack_max and nf_conntrack_buckets.

The former limits how many conntrack objects are allowed to exist
in each namespace.

The second sets the size of the hashtable.

As all entries are inserted twice (once for original direction, once for
reply), there should be at least twice as many buckets in the table than
the maximum number of conntrack objects that can exist at the same time.

Change the default multiplier to 1 and increase the chosen bucket sizes.
This results in the same nf_conntrack_max settings as before but reduces
the average bucket list length.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: add netfilter hooks to SRv6 data plane

2021-08-29T23:51:36+00:00

This patch introduces netfilter hooks for solving the problem that
conntrack couldn't record both inner flows and outer flows.

This patch also introduces a new sysctl toggle for enabling lightweight
tunnel netfilter hooks.

Signed-off-by: Ryoga Saito 
Signed-off-by: Pablo Neira Ayuso

netfilter: conntrack: remove offload_pickup sysctl again

2021-08-06T15:07:41+00:00

These two sysctls were added because the hardcoded defaults (2 minutes,
tcp, 30 seconds, udp) turned out to be too low for some setups.

They appeared in 5.14-rc1 so it should be fine to remove it again.

Marcelo convinced me that there should be no difference between a flow
that was offloaded vs. a flow that was not wrt. timeout handling.
Thus the default is changed to those for TCP established and UDP stream,
5 days and 120 seconds, respectively.

Marcelo also suggested to account for the timeout value used for the
offloading, this avoids increase beyond the value in the conntrack-sysctl
and will also instantly expire the conntrack entry with altered sysctls.

Example:
   nf_conntrack_udp_timeout_stream=60
   nf_flowtable_udp_timeout=60

This will remove offloaded udp flows after one minute, rather than two.

An earlier version of this patch also cleared the ASSURED bit to
allow nf_conntrack to evict the entry via early_drop (i.e., table full).
However, it looks like we can safely assume that connection timed out
via HW is still in established state, so this isn't needed.

Quoting Oz:
 [..] the hardware sends all packets with a set FIN flags to sw.
 [..] Connections that are aged in hardware are expected to be in the
 established state.

In case it turns out that back-to-sw-path transition can occur for
'dodgy' connections too (e.g., one side disappeared while software-path
would have been in RETRANS timeout), we can adjust this later.

Cc: Oz Shlomo 
Cc: Paul Blakey 
Suggested-by: Marcelo Ricardo Leitner 
Signed-off-by: Florian Westphal 
Reviewed-by: Marcelo Ricardo Leitner 
Reviewed-by: Oz Shlomo 
Signed-off-by: Pablo Neira Ayuso

netfilter: conntrack: add new sysctl to disable RST check

2021-07-06T12:15:12+00:00

This patch adds a new sysctl tcp_ignore_invalid_rst to disable marking
out of segments RSTs as INVALID.

Signed-off-by: Ali Abdallah 
Acked-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

docs: networking: Update connection tracking offload sysctl parameters

2021-06-18T22:00:17+00:00

Document the following connection offload configuration parameters:
- nf_flowtable_tcp_timeout
- nf_flowtable_tcp_pickup
- nf_flowtable_udp_timeout
- nf_flowtable_udp_pickup

Signed-off-by: Oz Shlomo 
Signed-off-by: Pablo Neira Ayuso

docs: networking: convert nf_conntrack-sysctl.txt to ReST

2020-04-30T19:56:36+00:00

- add SPDX header;
- add a document title;
- mark lists as such;
- add to networking/index.rst.

Signed-off-by: Mauro Carvalho Chehab 
Signed-off-by: David S. Miller