From: Tom Herbert <tom@herbertland.com>
To: davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org,
justin.iurman@uliege.be, willemdebruijn.kernel@gmail.com
Cc: Tom Herbert <tom@herbertland.com>,
Justin Iurman <justin.iurman@gmail.com>
Subject: [PATCH net-next v6 05/10] ipv6: Document defaults for max_{dst|hbh}_opts_number sysctls
Date: Mon, 2 Feb 2026 16:48:48 -0800 [thread overview]
Message-ID: <20260203004853.94438-6-tom@herbertland.com> (raw)
In-Reply-To: <20260203004853.94438-1-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>
Reviewed-by: Justin Iurman <justin.iurman@gmail.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
next prev parent reply other threads:[~2026-02-03 0:49 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-03 0:48 [PATCH net-next v6 00/10] ipv6: Address ext hdr DoS vulnerabilities Tom Herbert
2026-02-03 0:48 ` [PATCH net-next v6 01/10] ipv6: Check of max HBH or DestOp sysctl is zero and drop if it is Tom Herbert
2026-02-03 0:48 ` [PATCH net-next v6 02/10] ipv6: Cleanup IPv6 TLV definitions Tom Herbert
2026-02-03 0:48 ` [PATCH net-next v6 03/10] ipv6: Add case for IPV6_TLV_TNL_ENCAP_LIMIT in EH TLV switch Tom Herbert
2026-02-03 0:48 ` [PATCH net-next v6 04/10] ipv6: Set HBH and DestOpt limits to 2 Tom Herbert
2026-02-03 0:48 ` Tom Herbert [this message]
2026-02-03 0:48 ` [PATCH net-next v6 06/10] ipv6: Enforce Extension Header ordering Tom Herbert
2026-02-03 0:48 ` [PATCH net-next v6 07/10] ipv6: Document enforce_ext_hdr_order sysctl Tom Herbert
2026-02-03 0:48 ` [PATCH net-next v6 08/10] test: Add proto_nums.py in networking selftests Tom Herbert
2026-02-03 0:48 ` [PATCH net-next v6 09/10] test: Add ext_hdr.py " Tom Herbert
2026-02-03 0:48 ` [PATCH net-next v6 10/10] test: Add networking sefltest for eh limits Tom Herbert
2026-02-03 10:07 ` Paolo Abeni
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