[PATCH net-next v10 07/10] ipv6: Document enforce_ext_hdr_order sysctl

Tom Herbert
2026-05-04T18:53:02Z

Document the enforce_ext_hdr_order sysctl that controls whether
Extension Header order is enforced on receive.

Signed-off-by: Tom Herbert <tom@herbertland.com>
---
Documentation/networking/ip-sysctl.rst | 30 ++++++++++++++++++++++++++
1 file changed, 30 insertions(+)

diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index 453643c70c8d..fa0ed1936f59 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -2617,6 +2617,36 @@ ioam6_id_wide - LONG INTEGER

Default: 0xFFFFFFFFFFFFFF

+enforce_ext_hdr_order - BOOLEAN
+ Enforce recommended Extension Header ordering in RFC8200.
+ If the sysctl is set to 1 then the ordering is enforced in
+ received packets and each Extension Header may be present
+ at most once per packet (except for Destination Options that
+ may occur twice). If the sysctl is set to 0 then ordering is
+ not enforced and Extension Headers may be present in any
+ order and have any number of occurrences per packet (except
+ for Hop-by-Hop Options that must always be the first Extension
+ Header and occur at most once in a packet)).
+
+ The Extension Header order is:
+
+ IPv6 header
+ Hop-by-Hop Options header
+ Destination Options before the Routing header
+ Routing header
+ Fragment header
+ Authentication header
+ Encapsulating Security Payload header
+ Destination Options header
+ Upper-Layer header
+
+ Possible values:
+
+ - 0 (disabled)
+ - 1 (enabled)
+
+ Default: 1 (enabled)
+
IPv6 Fragmentation:

ip6frag_high_thresh - INTEGER
--
2.43.0