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 v5 5/7] ipv6: Document defaults for max_{dst|hbh}_opts_number sysctls
Date: Mon, 26 Jan 2026 11:48:24 -0800 [thread overview]
Message-ID: <20260126194826.236075-6-tom@herbertland.com> (raw)
In-Reply-To: <20260126194826.236075-1-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 | 24 +++++++++++++++---------
1 file changed, 15 insertions(+), 9 deletions(-)
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index bc9a01606daf..4f568b0e39d2 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -2475,19 +2475,25 @@ mld_qrv - INTEGER
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.
+ 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
next prev parent reply other threads:[~2026-01-26 19:48 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-26 19:48 [PATCH net-next v5 0/7] ipv6: Address ext hdr DoS vulnerabilities Tom Herbert
2026-01-26 19:48 ` [PATCH net-next v5 1/7] ipv6: Check of max HBH or DestOp sysctl is zero and drop if it is Tom Herbert
2026-01-27 17:49 ` Justin Iurman
2026-01-27 17:50 ` Justin Iurman
2026-01-26 19:48 ` [PATCH net-next v5 2/7] ipv6: Cleanup IPv6 TLV definitions Tom Herbert
2026-01-27 17:51 ` Justin Iurman
2026-01-29 5:30 ` Willem de Bruijn
2026-01-29 18:13 ` Justin Iurman
2026-01-29 19:01 ` Willem de Bruijn
2026-01-30 17:22 ` Tom Herbert
2026-02-01 8:48 ` Justin Iurman
2026-02-02 22:37 ` Tom Herbert
2026-01-26 19:48 ` [PATCH net-next v5 3/7] ipv6: Add case for IPV6_TLV_TNL_ENCAP_LIMIT in EH TLV switch Tom Herbert
2026-01-27 17:52 ` Justin Iurman
2026-01-29 5:31 ` Willem de Bruijn
2026-01-26 19:48 ` [PATCH net-next v5 4/7] ipv6: Set HBH and DestOpt limits to 2 Tom Herbert
2026-01-27 17:55 ` Justin Iurman
2026-01-26 19:48 ` Tom Herbert [this message]
2026-01-27 17:57 ` [PATCH net-next v5 5/7] ipv6: Document defaults for max_{dst|hbh}_opts_number sysctls Justin Iurman
2026-01-26 19:48 ` [PATCH net-next v5 6/7] ipv6: Enforce Extension Header ordering Tom Herbert
2026-01-27 19:48 ` Justin Iurman
2026-01-29 5:18 ` Willem de Bruijn
2026-01-29 18:07 ` Justin Iurman
2026-01-29 19:05 ` Willem de Bruijn
2026-01-29 20:13 ` Justin Iurman
2026-01-30 17:06 ` Tom Herbert
2026-01-31 17:24 ` Willem de Bruijn
2026-02-02 22:21 ` Tom Herbert
2026-01-26 19:48 ` [PATCH net-next v5 7/7] ipv6: Document enforce_ext_hdr_order sysctl Tom Herbert
2026-01-27 18:00 ` Justin Iurman
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