From a59166e470868d92f0813977817e99e699398af5 Mon Sep 17 00:00:00 2001 From: Robert Shearman Date: Fri, 10 Mar 2017 20:43:25 +0000 Subject: mpls: allow TTL propagation from IP packets to be configured Allow TTL propagation from IP packets to MPLS packets to be configured. Add a new optional LWT attribute, MPLS_IPTUNNEL_TTL, which allows the TTL to be set in the resulting MPLS packet, with the value of 0 having the semantics of enabling propagation of the TTL from the IP header (i.e. non-zero values disable propagation). Also allow the configuration to be overridden globally by reusing the same sysctl to control whether the TTL is propagated from IP packets into the MPLS header. If the per-LWT attribute is set then it overrides the global configuration. If the TTL isn't propagated then a default TTL value is used which can be configured via a new sysctl, "net.mpls.default_ttl". This is kept separate from the configuration of whether IP TTL propagation is enabled as it can be used in the future when non-IP payloads are supported (i.e. where there is no payload TTL that can be propagated). Signed-off-by: Robert Shearman Acked-by: David Ahern Tested-by: David Ahern Signed-off-by: David S. Miller --- Documentation/networking/mpls-sysctl.txt | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'Documentation') diff --git a/Documentation/networking/mpls-sysctl.txt b/Documentation/networking/mpls-sysctl.txt index 9badd1d6685f..2f24a1912a48 100644 --- a/Documentation/networking/mpls-sysctl.txt +++ b/Documentation/networking/mpls-sysctl.txt @@ -30,6 +30,14 @@ ip_ttl_propagate - BOOL 0 - disabled / RFC 3443 [Short] Pipe Model 1 - enabled / RFC 3443 Uniform Model (default) +default_ttl - BOOL + Default TTL value to use for MPLS packets where it cannot be + propagated from an IP header, either because one isn't present + or ip_ttl_propagate has been disabled. + + Possible values: 1 - 255 + Default: 255 + conf//input - BOOL Control whether packets can be input on this interface. -- cgit v1.2.3-59-g8ed1b