[tor-bugs] #18749 [Core Tor/Tor]: Consider only including one fallback per operator

[Tor Bug Tracker & Wiki]

#18749: Consider only including one fallback per operator
---------------------------------------------+-----------------------------
 Reporter:  teor                             |          Owner:
     Type:  enhancement                      |         Status:
 Priority:  Medium                           |  needs_review
Component:  Core Tor/Tor                     |      Milestone:  Tor:
 Severity:  Normal                           |  0.2.???
 Keywords:  029-proposed, TorCoreTeam201604  |        Version:
Parent ID:  #17158                           |     Resolution:
 Reviewer:                                   |  Actual Points:  8 hours
                                             |         Points:  small
                                             |        Sponsor:
---------------------------------------------+-----------------------------

Comment (by teor):

 One operator withdrew a fallback that was on the hard-coded fallback list.
 I have pushed a fixup after rebuilding the list. 11 fallbacks on the list
 changed (another turns up in the diff, but is just a reordering). It's
 good to see the list is stable, even though I changed 14
 whitelist/blacklist entries.

 Here is the updated analysis:

 '''One Per Operator'''

 * 100 fallbacks were selected
 * all 100 fallbacks passed the 15s consensus download check
 * 78 more are available from distinct operators
 * 102 were eliminated due to the "one per operator" restriction (family,
 contact, IP)

 '''Bandwidth'''

 The range of bandwidths selected is 6.0 - 67.2 MB/s.

 '''Network Diversity'''

 Here is the updated network diversity analysis:

 {{{
 27/100 = 27% of fallbacks are on IPv6

 There are 4/100 = 4% fallbacks in the IPv4 /16 containing 37.187.7.74
 32/100 = 32% of fallbacks are in an IPv4 /16 with other fallbacks
 There are 2/100 = 2% fallbacks in the IPv4 /24 containing 91.219.237.244
 2/100 = 2% of fallbacks are in an IPv4 /24 with other fallbacks

 There are 5/27 = 19% fallbacks in the IPv6 /32 containing
 [2001:41d0:e:f67::114]
 16/27 = 59% of fallbacks are in an IPv6 /32 with other fallbacks
 There are 3/27 = 11% fallbacks in the IPv6 /48 containing
 [2001:41d0:a:74a::1]
 5/27 = 19% of fallbacks are in an IPv6 /48 with other fallbacks
 There are 2/27 = 7% fallbacks in the IPv6 /64 containing
 [2a03:b0c0:3:d0::208:5001]
 2/27 = 7% of fallbacks are in an IPv6 /64 with other fallbacks

 40/100 = 40% of fallbacks are on IPv4 ORPort 443
 42/100 = 42% of fallbacks are on IPv4 ORPort 9001
 18/100 = 18% of fallbacks are on other IPv4 ORPorts

 10/27 = 37% of IPv6 fallbacks are on IPv6 ORPort 443
 7/27 = 26% of IPv6 fallbacks are on IPv6 ORPort 9001
 10/27 = 37% of IPv6 fallbacks are on other IPv6 ORPorts

 38/100 = 38% of fallbacks are on DirPort 80
 44/100 = 44% of fallbacks are on DirPort 9030
 18/100 = 18% of fallbacks are on other DirPorts

 22/100 = 22% of fallbacks have the Exit flag
 }}}

 This isn't a significant change from the previous list.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/18749#comment:12>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online