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 --- include/uapi/linux/rtnetlink.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h index 75fcf5eff093..3dd72aee4d32 100644 --- a/include/uapi/linux/rtnetlink.h +++ b/include/uapi/linux/rtnetlink.h @@ -319,6 +319,7 @@ enum rtattr_type_t { RTA_EXPIRES, RTA_PAD, RTA_UID, + RTA_TTL_PROPAGATE, __RTA_MAX }; -- cgit v1.2.3 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 --- include/uapi/linux/mpls_iptunnel.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/mpls_iptunnel.h b/include/uapi/linux/mpls_iptunnel.h index d80a0498f77e..f5e45095b0bb 100644 --- a/include/uapi/linux/mpls_iptunnel.h +++ b/include/uapi/linux/mpls_iptunnel.h @@ -16,11 +16,13 @@ /* MPLS tunnel attributes * [RTA_ENCAP] = { * [MPLS_IPTUNNEL_DST] + * [MPLS_IPTUNNEL_TTL] * } */ enum { MPLS_IPTUNNEL_UNSPEC, MPLS_IPTUNNEL_DST, + MPLS_IPTUNNEL_TTL, __MPLS_IPTUNNEL_MAX, }; #define MPLS_IPTUNNEL_MAX (__MPLS_IPTUNNEL_MAX - 1) -- cgit v1.2.3