public inbox for netdev@vger.kernel.org
 help / color / mirror / Atom feed
From: Tom Herbert <tom@herbertland.com>
To: davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org,
	justin.iurman@uliege.be
Cc: Tom Herbert <tom@herbertland.com>
Subject: [PATCH net-next v4 5/7] ipv6: Document defaults for max_{dst|hbh}_opts_number sysctls
Date: Wed, 21 Jan 2026 13:49:23 -0800	[thread overview]
Message-ID: <20260121214925.112604-6-tom@herbertland.com> (raw)
In-Reply-To: <20260121214925.112604-1-tom@herbertland.com>

In the descriptions of max_dst_opts_number and max_hbh_opts_number
sysctls add text about how a zero setting means that a packet with
any Destination or Hop-by-Hop options is dropped.

Report the defaults for max_dst_opts_number and max_hbh_opts_number
are 2 which means up to two options may be accepted.

Signed-off-by: Tom Herbert <tom@herbertland.com>
---
 Documentation/networking/ip-sysctl.rst | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index bc9a01606daf..5051fe653c96 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -2474,20 +2474,26 @@ mld_qrv - INTEGER
 	Minimum: 1 (as specified by RFC6636 4.5)
 
 max_dst_opts_number - INTEGER
-	Maximum number of non-padding TLVs allowed in a Destination
-	options extension header. If this value is less than zero
-	then unknown options are disallowed and the number of known
-	TLVs allowed is the absolute value of this number.
+        Maximum number of non-padding TLVs allowed in a Destination
+        options extension header. If this value is zero then receive
+        Destination Options processing is disabled in which case packets
+        with the Destination Options extension header are dropped. If
+        this value is less than zero then unknown options are disallowed
+        and the number of known TLVs allowed is the absolute value of
+        this number.
 
-	Default: 8
+        Default: 2
 
 max_hbh_opts_number - INTEGER
 	Maximum number of non-padding TLVs allowed in a Hop-by-Hop
-	options extension header. If this value is less than zero
-	then unknown options are disallowed and the number of known
-	TLVs allowed is the absolute value of this number.
-
-	Default: 8
+	options extension header. If this value is zero then receive
+        Hop-by-Hop Options processing is disabled in which case packets
+        with the Hop-by-Hop Options extension header are dropped.
+        If this value is less than zero then unknown options are disallowed
+        and the number of known TLVs allowed is the absolute value of this
+        number.
+
+        Default: 2
 
 max_dst_opts_length - INTEGER
 	Maximum length allowed for a Destination options extension
-- 
2.43.0


  parent reply	other threads:[~2026-01-21 21:49 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-01-21 21:49 [PATCH net-next v4 0/7] ipv6: Address ext hdr DoS vulnerabilities Tom Herbert
2026-01-21 21:49 ` [PATCH net-next v4 1/7] ipv6: Check of max HBH or DestOp sysctl is zero and drop if it is Tom Herbert
2026-01-23 21:16   ` Justin Iurman
2026-01-21 21:49 ` [PATCH net-next v4 2/7] ipv6: Cleanup IPv6 TLV definitions Tom Herbert
2026-01-23 21:19   ` Justin Iurman
2026-01-21 21:49 ` [PATCH net-next v4 3/7] ipv6: Add case for IPV6_TLV_TNL_ENCAP_LIMIT in EH TLV switch Tom Herbert
2026-01-21 21:49 ` [PATCH net-next v4 4/7] ipv6: Set HBH and DestOpt limits to 2 Tom Herbert
2026-01-21 21:49 ` Tom Herbert [this message]
2026-01-21 21:49 ` [PATCH net-next v4 6/7] ipv6: Enforce Extension Header ordering Tom Herbert
2026-01-23 21:35   ` Justin Iurman
2026-01-26 16:56     ` Tom Herbert
2026-01-26 19:23       ` Justin Iurman
2026-01-26 19:38         ` Tom Herbert
2026-01-21 21:49 ` [PATCH net-next v4 7/7] ipv6: Document enforce_ext_hdr_order sysctl Tom Herbert

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20260121214925.112604-6-tom@herbertland.com \
    --to=tom@herbertland.com \
    --cc=davem@davemloft.net \
    --cc=justin.iurman@uliege.be \
    --cc=kuba@kernel.org \
    --cc=netdev@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox