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Mon, 04 May 2026 11:52:57 -0700 (PDT) From: Tom Herbert X-Google-Original-From: Tom Herbert To: davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org, justin.iurman@uliege.be, willemdebruijn.kernel@gmail.com, pabeni@redhat.com, horms@kernel.org Cc: Tom Herbert , Justin Iurman Subject: [PATCH net-next v10 05/10] ipv6: Document defaults for max_{dst|hbh}_opts_number sysctls Date: Mon, 4 May 2026 11:51:17 -0700 Message-ID: <20260504185122.50642-6-tom@xdpnet.ai> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260504185122.50642-1-tom@xdpnet.ai> References: <20260504185122.50642-1-tom@xdpnet.ai> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Tom Herbert 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 Reviewed-by: Justin Iurman --- Documentation/networking/ip-sysctl.rst | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index 2e3a746fcc6d..453643c70c8d 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -2511,19 +2511,25 @@ 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. + 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: 8 + Default: 2 max_dst_opts_length - INTEGER Maximum length allowed for a Destination options extension -- 2.43.0