linux-toradex.git/Documentation/networking/ip-sysctl.rst, branch v6.17

docs: Fix name for net.ipv4.udp_child_hash_entries

2025-08-12T11:03:13+00:00

udp_child_ehash_entries -> udp_child_hash_entries

Fixes: 9804985bf27f ("udp: Introduce optional per-netns hash table.")
Signed-off-by: Jordan Rife 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20250808185800.1189042-1-jordan@jrife.io
Signed-off-by: Paolo Abeni

ipv6: add `force_forwarding` sysctl to enable per-interface forwarding

2025-07-25T20:06:19+00:00

It is currently impossible to enable ipv6 forwarding on a per-interface
basis like in ipv4. To enable forwarding on an ipv6 interface we need to
enable it on all interfaces and disable it on the other interfaces using
a netfilter rule. This is especially cumbersome if you have lots of
interfaces and only want to enable forwarding on a few. According to the
sysctl docs [0] the `net.ipv6.conf.all.forwarding` enables forwarding
for all interfaces, while the interface-specific
`net.ipv6.conf..forwarding` configures the interface
Host/Router configuration.

Introduce a new sysctl flag `force_forwarding`, which can be set on every
interface. The ip6_forwarding function will then check if the global
forwarding flag OR the force_forwarding flag is active and forward the
packet.

To preserve backwards-compatibility reset the flag (on all interfaces)
to 0 if the net.ipv6.conf.all.forwarding flag is set to 0.

Add a short selftest that checks if a packet gets forwarded with and
without `force_forwarding`.

[0]: https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt

Acked-by: Nicolas Dichtel 
Signed-off-by: Gabriel Goller 
Link: https://patch.msgid.link/20250722081847.132632-1-g.goller@proxmox.com
Signed-off-by: Jakub Kicinski

tcp: update the outdated ref draft-ietf-tcpm-rack

2025-07-08T16:01:52+00:00

As RACK-TLP was published as a standards-track RFC8985,
so the outdated ref draft-ietf-tcpm-rack need to be updated.

Signed-off-by: Xin Guo 
Reviewed-by: Neal Cardwell 
Link: https://patch.msgid.link/20250705163647.301231-1-guoxin0309@gmail.com
Signed-off-by: Jakub Kicinski

net: ip-sysctl: Add link to SCTP IPv4 scoping draft

2025-07-03T13:51:45+00:00

addr_scope_policy description contains pointer to SCTP IPv4 scoping
draft but not its IETF Datatracker link. Add it.

Signed-off-by: Bagas Sanjaya 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20250701031300.19088-6-bagasdotme@gmail.com
Signed-off-by: Paolo Abeni

net: ip-sysctl: Format SCTP-related memory parameters description as bullet list

2025-07-03T13:51:45+00:00

The description for vector elements of SCTP-related memory usage
parameters (sctp{r,w,}mem) is formatted as normal paragraphs rather than
bullet list. Convert the description to the latter.

Signed-off-by: Bagas Sanjaya 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20250701031300.19088-5-bagasdotme@gmail.com
Signed-off-by: Paolo Abeni

net: ip-sysctl: Format pf_{enable,expose} boolean lists as bullet lists

2025-07-03T13:51:45+00:00

These lists' items were separated by newlines but without bullet list
marker. Turn the lists into proper bullet list.

While at it, also reword values description for pf_expose to not repeat
mentioning SCTP_PEER_ADDR_CHANGE and SCTP_GET_PEER_ADDR_INFO sockopt.

Signed-off-by: Bagas Sanjaya 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20250701031300.19088-4-bagasdotme@gmail.com
Signed-off-by: Paolo Abeni

net: ip-sysctl: Format possible value range of ioam6_id{,_wide} as bullet list

2025-07-03T13:51:44+00:00

Format possible value range bounds of ioam6_id and ioam6_id_wide as
bullet list instead of running paragraph.

Signed-off-by: Bagas Sanjaya 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20250701031300.19088-3-bagasdotme@gmail.com
Signed-off-by: Paolo Abeni

net: ip-sysctl: Format Private VLAN proxy arp aliases as bullet list

2025-07-03T13:51:44+00:00

Alias names list for private VLAN proxy arp technology is formatted as
indented paragraph instead. Make it bullet list as it is better fit for
this purpose.

Signed-off-by: Bagas Sanjaya 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20250701031300.19088-2-bagasdotme@gmail.com
Signed-off-by: Paolo Abeni

docs: net: sysctl documentation cleanup

2025-06-26T13:02:00+00:00

Add missing default values for networking sysctl parameters and
standardize documentation:
- Use "0 (disabled)" / "1 (enabled)" format consistently
- Fix cipso_rbm_struct_valid -> cipso_rbm_strictvalid typo
- Convert fwmark_reflect description to enabled/disabled terminology
- Document possible values for tcp_autocorking

Also addresses formatting inconsistencies in touched parameters.

Signed-off-by: Abdelrahman Fekry 
Reviewed-by: Bagas Sanjaya 
Link: https://patch.msgid.link/20250624150923.40590-1-abdelrahmanfekry375@gmail.com
Signed-off-by: Paolo Abeni

tcp: remove obsolete and unused RFC3517/RFC6675 loss recovery code

2025-06-17T23:18:48+00:00

RACK-TLP loss detection has been enabled as the default loss detection
algorithm for Linux TCP since 2018, in:

 commit b38a51fec1c1 ("tcp: disable RFC6675 loss detection")

In case users ran into unexpected bugs or performance regressions,
that commit allowed Linux system administrators to revert to using
RFC3517/RFC6675 loss recovery by setting net.ipv4.tcp_recovery to 0.

In the seven years since 2018, our team has not heard reports of
anyone reverting Linux TCP to use RFC3517/RFC6675 loss recovery, and
we can't find any record in web searches of such a revert.

RACK-TLP was published as a standards-track RFC, RFC8985, in February
2021.

Several other major TCP implementations have default-enabled RACK-TLP
at this point as well.

RACK-TLP offers several significant performance advantages over
RFC3517/RFC6675 loss recovery, including much better performance in
the common cases of tail drops, lost retransmissions, and reordering.

It is now time to remove the obsolete and unused RFC3517/RFC6675 loss
recovery code. This will allow a substantial simplification of the
Linux TCP code base, and removes 12 bytes of state in every tcp_sock
for 64-bit machines (8 bytes on 32-bit machines).

To arrange the commits in reasonable sizes, this patch series is split
into 3 commits. The following 2 commits remove bookkeeping state and
code that is no longer needed after this removal of RFC3517/RFC6675
loss recovery.

Suggested-by: Yuchung Cheng 
Signed-off-by: Neal Cardwell 
Reviewed-by: Yuchung Cheng 
Reviewed-by: Eric Dumazet 
Link: https://patch.msgid.link/20250615001435.2390793-2-ncardwell.sw@gmail.com
Signed-off-by: Jakub Kicinski