For that, I suggest you look at this application,isatapd (requires root).
It seems to match your description;
ISATAP is a IPv6 in IPv4 tunnel mechanism that allows clients to get a
global routeable IPv6 address over an IPv4 only network. The isatapd
tool for Linux helps with the automatic configuration of the tunnel
and the client endpoint and is shipped in this app and run as root.
Alternatively the same developer has a similar app IPv6Config (root required). From description;
IPv6Config allows to configure some of the IPv6 kernel settings.
Currently, it allows to automatically enable the "Privacy Extensions
for Stateless Address Autoconfiguration in IPv6" as specified in IETF
RFC4941 and implemented by the standard Linux kernel and to establish
6to4 tunnels for IPv6 connectivity with providers that only provide
IPv4 addresses so far.
Hope this helps