r0 = socket$inet6_udp(0xa, 0x2, 0x0)
ioctl$sock_ipv6_tunnel_SIOCGETTUNNEL(r0, 0x89f0, &(0x7f0000000140)={'sit0\x00', &(0x7f0000008900)={'ip6gre0\x00', 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, @private2, @ipv4={'\x00', '\xff\xff', @loopback}}})