[tor-relays] is it possible to relay using ipv6?

[Zack Weinberg]

On Sun, Nov 27, 2016 at 6:01 PM, teor <teor2345 at gmail.com> wrote:
>
> If IPv6 penetration among Tor relay ISPs/ASs is as high as you say, why
> do only:
>
> 7.6% (541/7145) of relays have an IPv6 OR address
> 17.3% (7972687/45960632) of relay bandwidth has an IPv6 OR address
>
> With IPv6 relay bandwidth this low, we can't even have clients try IPv6
> by default - there are too few relays to meet Tor's existing 60% path
> threshold in get_frac_paths_needed_for_circs().

I want to add something to these figures: (modified code at end)

7.5% (535/7171) of relays have an IPv6 OR address
16.8% (7800233/46493235) of relay bandwidth has an IPv6 OR address

16.9% (343/2034) of guard relays have an IPv6 OR address
23.3% (7364620/31664680) of guard relay bandwidth has an IPv6 OR address

9.8% (89/908) of exit relays have an IPv6 OR address
18.2% (1954308/10754720) of exit relay bandwidth has an IPv6 OR address

This is better than I expected -- I thought IPv6-capable exit relays
in particular would be few and far between.  Still, I worry that we
might hit a ceiling on IPv6 adoption by exits, because exit-friendly
connectivity tends to come from places where keeping up with the
bleeding edge in network gear isn't the top priority, like libraries
and universities.  Despite how many network researchers we have here,
CMU (and therefore my exit node) doesn't have IPv6; campus IT tells me
that it's on their list but there are several higher-priority hardware
upgrades that need to happen first, and the ETA has been "three to
five years from now" for my entire time here.

zw

#! /usr/bin/python3
import stem.descriptor.remote
from stem import Flag

consensus = stem.descriptor.remote.DescriptorDownloader().get_consensus()
total_count = total_bw = 0
total_guard_count = total_guard_bw = 0
total_exit_count = total_exit_bw = 0
ipv6_count = ipv6_bw = 0
ipv6_guard_count = ipv6_guard_bw = 0
ipv6_exit_count = ipv6_exit_bw = 0

for relay in consensus:
    is_guard = Flag.GUARD in relay.flags
    is_exit  = Flag.EXIT in relay.flags
    for address in relay.or_addresses:
        if address[2]: # is_ipv6
            has_ipv6 = True
            break
    else:
        has_ipv6 = False

    if has_ipv6:
        ipv6_count += 1
        ipv6_bw += relay.bandwidth
        if is_guard:
            ipv6_guard_count += 1
            ipv6_guard_bw += relay.bandwidth
        if is_exit:
            ipv6_exit_count += 1
            ipv6_exit_bw += relay.bandwidth

    total_count += 1
    total_bw += relay.bandwidth
    if is_exit:
        total_exit_count += 1
        total_exit_bw += relay.bandwidth
    # Relays with both EXIT and GUARD are, IIUC, used only as exits.
    elif is_guard:
        total_guard_count += 1
        total_guard_bw += relay.bandwidth

print("%.1f%% (%d/%d) of relays have an IPv6 OR address" %
      (ipv6_count*100.0/total_count, ipv6_count, total_count))
print("%.1f%% (%d/%d) of relay bandwidth has an IPv6 OR address" %
      (ipv6_bw*100.0/total_bw, ipv6_bw, total_bw))
print()
print("%.1f%% (%d/%d) of guard relays have an IPv6 OR address" %
      (ipv6_guard_count*100.0/total_guard_count,
       ipv6_guard_count, total_guard_count))
print("%.1f%% (%d/%d) of guard relay bandwidth has an IPv6 OR address" %
      (ipv6_guard_bw*100.0/total_guard_bw, ipv6_guard_bw, total_guard_bw))
print()
print("%.1f%% (%d/%d) of exit relays have an IPv6 OR address" %
      (ipv6_exit_count*100.0/total_exit_count,
       ipv6_exit_count, total_exit_count))
print("%.1f%% (%d/%d) of exit relay bandwidth has an IPv6 OR address" %
      (ipv6_exit_bw*100.0/total_exit_bw, ipv6_exit_bw, total_exit_bw))