From 5b441ac8784c1e7f3c619f14da4c3f52e87348d5 Mon Sep 17 00:00:00 2001 From: Robert Shearman Date: Fri, 10 Mar 2017 20:43:24 +0000 Subject: mpls: allow TTL propagation to IP packets to be configured Provide the ability to control on a per-route basis whether the TTL value from an MPLS packet is propagated to an IPv4/IPv6 packet when the last label is popped as per the theoretical model in RFC 3443 through a new route attribute, RTA_TTL_PROPAGATE which can be 0 to mean disable propagation and 1 to mean enable propagation. In order to provide the ability to change the behaviour for packets arriving with IPv4/IPv6 Explicit Null labels and to provide an easy way for a user to change the behaviour for all existing routes without having to reprogram them, a global knob is provided. This is done through the addition of a new per-namespace sysctl, "net.mpls.ip_ttl_propagate", which defaults to enabled. If the per-route attribute is set (either enabled or disabled) then it overrides the global configuration. Signed-off-by: Robert Shearman Acked-by: David Ahern Tested-by: David Ahern Signed-off-by: David S. Miller --- Documentation/networking/mpls-sysctl.txt | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'Documentation/networking') diff --git a/Documentation/networking/mpls-sysctl.txt b/Documentation/networking/mpls-sysctl.txt index 15d8d16934fd..9badd1d6685f 100644 --- a/Documentation/networking/mpls-sysctl.txt +++ b/Documentation/networking/mpls-sysctl.txt @@ -19,6 +19,17 @@ platform_labels - INTEGER Possible values: 0 - 1048575 Default: 0 +ip_ttl_propagate - BOOL + Control whether TTL is propagated from the IPv4/IPv6 header to + the MPLS header on imposing labels and propagated from the + MPLS header to the IPv4/IPv6 header on popping the last label. + + If disabled, the MPLS transport network will appear as a + single hop to transit traffic. + + 0 - disabled / RFC 3443 [Short] Pipe Model + 1 - enabled / RFC 3443 Uniform Model (default) + conf//input - BOOL Control whether packets can be input on this interface. -- cgit v1.2.3