[tor-bugs] #33818 [Core Tor/Tor]: Add options for clients and relays to enable IPv6 extends
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Sun Apr 5 13:38:05 UTC 2020
#33818: Add options for clients and relays to enable IPv6 extends
---------------------------+------------------------------------
Reporter: teor | Owner: teor
Type: task | Status: assigned
Priority: Medium | Milestone: Tor: 0.4.4.x-final
Component: Core Tor/Tor | Version:
Severity: Normal | Resolution:
Keywords: ipv6, prop311 | Actual Points:
Parent ID: #33220 | Points: 1
Reviewer: | Sponsor: Sponsor55-must
---------------------------+------------------------------------
Old description:
> To help with testing and future network upgrades, we want to add options
> that:
> * make clients and relays send IPv6 addresses in extend cells, and
> * make relays perform extends over IPv6.
>
> **General Options**
>
> ExtendByIPv6ORPort (like ExtendByEd25519ID):
>
> If this option is set to 1, Tor tries to include a relay’s IPv6 ORPort
> when telling the preceding relay in a circuit to extend to it. If this
> option is set to 0, Tor never includes an IPv6 ORPort when extending
> circuits. (And Tor relays disable IPv6 reachability self-tests.) If the
> option is set to "auto", Tor obeys a parameter in the consensus document.
> If the consensus parameter is not set:
> * relays include IPv6 ORPorts in extend cells, but
> * clients and bridges do not include IPv6 ORPort in extend cells.
> (Default: auto)
>
> **Relay and Bridge Options**
>
> ExtendAllowIPv6Addresses (like ExtendAllowPrivateAddresses):
>
> Relays and bridges only. When this option is set to 1, Tor will connect
> to relays on IPv6 addresses. In particular, Tor relays and bridges will
> allow EXTEND requests to IPv6 addresses.
>
> This option does not apply to clients, or direct OR connections initiated
> by relays or bridges. Use ClientUseIPv6 and ClientPreferIPv6ORPort to
> enable direct IPv6 connections.
>
> If this option is set to 0, Tor will not connect to IPv6 ORPorts when
> extending circuits. If the option is set to "auto", Tor obeys a parameter
> in the consensus document. If the consensus parameter is not set:
> * relays allow IPv6 extends, but
> * bridges do not allow IPv6 extends. (Default: auto)
>
> **Proposal Notes**
>
> The design and option names are changed from section 4.4.4 of proposal
> 311, for the following reasons:
> * consistent design:
> * simpler code: decide based on public_server_mode(), rather than
> circuit purpose
> * relay reachability and other cells can't be distinguished
> * relays include IPv6 first, because they don't require anonymity
> * clients don't include IPv6 (until there are more IPv6 relays)
> * bridges match clients
> * consistency with existing options
>
> See:
> https://github.com/torproject/torspec/blob/master/proposals/311-relay-
> ipv6-reachability.txt#L535
New description:
To help with testing and future network upgrades, we want to add options
that:
* make clients and relays send IPv6 addresses in extend cells, and
* make relays perform extends over IPv6.
**General Options**
ExtendByIPv6ORPort (like ExtendByEd25519ID):
If this option is set to 1, Tor tries to include a relay’s IPv6 ORPort
when telling the preceding relay in a circuit to extend to it. When IPv6
extends are enabled, relays and bridges use them to perform IPv6
reachability self-tests. Once these tests succeed, they publish their
descriptors. (See AssumeReachable for more details.)
If this option is set to 0, Tor never includes an IPv6 ORPort when
extending circuits. Tor relays and bridges are unable to perform IPv6
reachability self-tests.
If the option is set to "auto", Tor obeys a parameter in the consensus
document. If the consensus parameter is not set:
* relays include IPv6 ORPorts in extend cells,
* bridges only include IPv6 ORPorts in the final extend in reachability
self-test circuits,
* clients do not include IPv6 ORPorts in extend cells.
(Default: auto)
**Relay and Bridge Options**
ExtendAllowIPv6Addresses (like ExtendAllowPrivateAddresses):
Relays and bridges only.
When this option is set to 1, Tor relays and bridges allow EXTEND requests
to IPv6 addresses. When IPv6 extends are enabled in their own
configurations, relays and bridges assume that other relays in the network
will also allow IPv6 extends. So they perform IPv6 reachability self-
tests, before publishing their descriptors. (See AssumeReachable for more
details.)
This option does not apply to clients, or direct OR connections initiated
by relays or bridges. Use ClientUseIPv6 and ClientPreferIPv6ORPort to
enable direct IPv6 OR connections.
If this option is set to 0, Tor relays and bridges do not connect to IPv6
ORPorts when extending circuits. When IPv6 extends are disabled, relays
and bridges assume that other relays in the network may also refuse IPv6
extends. So they continue to perform IPv6 reachability self-tests, but
consider them unreliable. They publish their descriptors, regardless of
the outcome of the tests.
If the option is set to "auto", Tor obeys a parameter in the consensus
document. If the consensus parameter is not set:
* relays allow IPv6 extends,
* bridges do not allow IPv6 extends, and
* relays and bridges perform IPv6 reachability self-tests, before
publishing their descriptors.
(Default: auto)
**Proposal Notes**
The design and option names are changed from section 4.4.4 of proposal
311, for the following reasons:
* consistent design:
* simpler code: decide based on public_server_mode(), rather than
circuit purpose
* relay reachability and other cells can't be distinguished
* relays include IPv6 first, because they don't require anonymity
* clients don't include IPv6 (until there are more IPv6 relays)
* bridges match clients
* consistency with existing options
* AssumeIPv6Reachable is no longer required, it is obsoleted by:
* AssumeReachable 1 (skip IPv4 and IPv6 reachability)
* ExtendByIPv6ORPort 0 (skip IPv6 reachability)
* ExtendAllowIPv6Addresses 0 (only log IPv6 reachability)
See:
https://github.com/torproject/torspec/blob/master/proposals/311-relay-
ipv6-reachability.txt#L535
--
Comment (by teor):
Describe options and reachability behaviour.
--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/33818#comment:1>
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