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authorArun Ajith S <aajith@arista.com>2022-04-15 11:34:02 +0300
committerDavid S. Miller <davem@davemloft.net>2022-04-17 15:23:49 +0300
commitf9a2fb73318eb4dbf8cd84866b8b0dd012d8b116 (patch)
tree1441aad939fad8f1112d3bfb24eec862e472f0ee /Documentation/networking
parent0339d25a2807d913f5645b8d5e485640915f9702 (diff)
downloadlinux-f9a2fb73318eb4dbf8cd84866b8b0dd012d8b116.tar.xz
net/ipv6: Introduce accept_unsolicited_na knob to implement router-side changes for RFC9131
Add a new neighbour cache entry in STALE state for routers on receiving an unsolicited (gratuitous) neighbour advertisement with target link-layer-address option specified. This is similar to the arp_accept configuration for IPv4. A new sysctl endpoint is created to turn on this behaviour: /proc/sys/net/ipv6/conf/interface/accept_unsolicited_na. Signed-off-by: Arun Ajith S <aajith@arista.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation/networking')
-rw-r--r--Documentation/networking/ip-sysctl.rst27
1 files changed, 27 insertions, 0 deletions
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index b0024aa7b051..433f2e4a5fed 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -2467,6 +2467,33 @@ drop_unsolicited_na - BOOLEAN
By default this is turned off.
+accept_unsolicited_na - BOOLEAN
+ Add a new neighbour cache entry in STALE state for routers on receiving an
+ unsolicited neighbour advertisement with target link-layer address option
+ specified. This is as per router-side behavior documented in RFC9131.
+ This has lower precedence than drop_unsolicited_na.
+
+ ==== ====== ====== ==============================================
+ drop accept fwding behaviour
+ ---- ------ ------ ----------------------------------------------
+ 1 X X Drop NA packet and don't pass up the stack
+ 0 0 X Pass NA packet up the stack, don't update NC
+ 0 1 0 Pass NA packet up the stack, don't update NC
+ 0 1 1 Pass NA packet up the stack, and add a STALE
+ NC entry
+ ==== ====== ====== ==============================================
+
+ This will optimize the return path for the initial off-link communication
+ that is initiated by a directly connected host, by ensuring that
+ the first-hop router which turns on this setting doesn't have to
+ buffer the initial return packets to do neighbour-solicitation.
+ The prerequisite is that the host is configured to send
+ unsolicited neighbour advertisements on interface bringup.
+ This setting should be used in conjunction with the ndisc_notify setting
+ on the host to satisfy this prerequisite.
+
+ By default this is turned off.
+
enhanced_dad - BOOLEAN
Include a nonce option in the IPv6 neighbor solicitation messages used for
duplicate address detection per RFC7527. A received DAD NS will only signal