/proc/sys/net/conf/<iface>/seg6_* variables:

seg6_enabled - BOOL
	Accept or drop SR-enabled IPv6 packets on this interface.

	Relevant packets are those with SRH present and DA = local.

	0 - disabled (default)
	not 0 - enabled

seg6_require_hmac - INTEGER
	Define HMAC policy for ingress SR-enabled packets on this interface.

	-1 - Ignore HMAC field
	0 - Accept SR packets without HMAC, validate SR packets with HMAC
	1 - Drop SR packets without HMAC, validate SR packets with HMAC

	Default is 0.