Tor Ipv6-Patch

Marcus Wolschon marcus at
Tue Dec 4 13:18:02 UTC 2007

Hash: SHA1

Michael G. Reed schrieb:
> On Tue, 4 Dec 2007, Nick Mathewson wrote:
> |>  - You're right that the preferred way to store addresses that could be
> |>    either IPv4 or IPv6 is indeed with tor_addr_t.  (Thanks for the
> |>    reminder, BTW: I fixed tor_addr_t to be a tagged union of in_addr and
> |>    in6_addr, not of sockaddr_in and sockaddr_in6.)
> Not sure if it applies in this case or not (I'm looking at this
> comment from 50,000 feet, not having looked at the actual usage/code),
> but an in6_addr is insufficient to fully specify all IPv6 addresses
> (it is fine for global-scope addresses, but cannot handle
> link/site-scoped addresses -

Hello Michael,

inside tor we only deal with addresses we are listening on and
the addresses of target-hosts and tor-servers.
I am aware of the scope-field but do not think there is need for
this in tor. Routing is done by the underlying operating-system
and as far as I could see we never deal with nexthops or the
local default-router but instead only with global scoped addresses
and ::1 .
Is anyone aware of a place in tor where this may be an issue?

The only place I could imaging is some user manually binding
tor to a fe80:... but this will fail as soon as privacy-enhancements
are enabled as the link-local-address changes and does not reveal
the mac-address. (As far as I understood that feature.)
If that host has no global ipv6-address at all, it cannot have a route
to the outside world (no NAT in ipv6 on purpose) thus a tor-node with
no global-scoped address would be useless.

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