[tor-bugs] #30794 [Circumvention/Censorship analysis]: Create lightweight censorship analyser for users

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#30794: Create lightweight censorship analyser for users
-----------------------------------------------+---------------------------
 Reporter:  phw                                |          Owner:  phw
     Type:  project                            |         Status:
                                               |  needs_review
 Priority:  Medium                             |      Milestone:
Component:  Circumvention/Censorship analysis  |        Version:
 Severity:  Normal                             |     Resolution:
 Keywords:  tbb-bridges, s30-o22a2             |  Actual Points:
Parent ID:  #31279                             |         Points:  5
 Reviewer:  cohosh                             |        Sponsor:
                                               |  Sponsor30-can
-----------------------------------------------+---------------------------
Changes (by phw):

 * status:  assigned => needs_review
 * reviewer:   => cohosh


Comment:

 Replying to [comment:3 dcf]:
 >  * If emma.exe is double-clicked on Windows, it may open a terminal
 window, display the output, then close the window again. Perhaps in the
 default configuration, it should append its output (timestamped) to a
 file.
 >  * For reachability tests, it would be good to show an elapsed time, in
 both the reachable and unreachable case.
 >  * For the DNS lookups, it would be nice to see what names were
 resolved. This is in case there are multiple versions of the program
 distributed, so we can tell from the output whether the domains included a
 particular one that we care about.
 [[br]]
 These are great ideas, thanks! I addressed your feedback as follows:
 * By default, the tool now writes its report to a file unless given the
 `-stdout` flag.
 * Each test now shows its execution time.
 * I replaced DNS lookups with HTTPS requests.

 Here's a run from my laptop:
 {{{
 $ ./bin/emma -stdout
 2020/04/24 11:52:47 Starting analysis.
 Time: 2020-04-24 11:52:47.933101623 -0700 PDT m=+0.000827916
 Testing default bridges:
   ✓ 38.229.1.78:80                        71ms
   ✓ 38.229.33.83:80                       49ms
   ✓ 192.95.36.142:443                     74ms
   ✓ 37.218.240.34:40035                  166ms
   ✓ 37.218.245.14:38224                  147ms
   ✓ 85.31.186.98:443                     165ms
   ✓ 85.31.186.26:443                     166ms
   ✓ 144.217.20.138:80                     71ms
   ✓ 193.11.166.194:27015                 165ms
   ✓ 193.11.166.194:27020                 163ms
   ✓ 193.11.166.194:27025                 166ms
   ✓ 209.148.46.65:443                    107ms
   ✗ 146.57.248.225:22                       3s  error: dial tcp
 146.57.248.225:22: i/o timeout
   ✓ 45.145.95.6:27015                    158ms
   ✓ [2a0c:4d80:42:702::1]:27015          154ms
 Testing websites:
   ✓ https://gettor.torproject.org        896ms
   ✓ https://ajax.aspnetcdn.com           489ms
   ✓ https://bridges.torproject.org       521ms
   ✓ https://torproject.org              1.074s
 Testing directory authorities.
   ✓ 128.31.0.39:9131                      75ms
   ✓ [2001:858:2:2:aabb:0:563b:1526]:443  183ms
   ✓ 86.59.21.38:80                       179ms
   ✓ 45.66.33.45:80                       160ms
   ✓ 66.111.2.131:9030                     67ms
   ✓ [2001:638:a000:4140::ffff:189]:443   158ms
   ✓ 131.188.40.189:80                    162ms
   ✓ [2001:678:558:1000::244]:443         157ms
   ✓ 193.23.244.244:80                    157ms
   ✓ [2001:67c:289c::9]:80                161ms
   ✓ 171.25.193.9:443                     173ms
   ✓ 154.35.175.225:80                     49ms
   ✓ 199.58.81.140:80                      80ms
   ✓ [2620:13:4000:6000::1000:118]:443     39ms
   ✓ 204.13.164.118:80                     37ms
 Testing relays.
   ✓ 193.11.166.196:443                   167ms
   ✓ 81.7.18.7:9001                       164ms
   ✓ 91.143.80.147:995                    163ms
   ✗ 162.247.74.7:443                        3s  error: dial tcp
 162.247.74.7:443: i/o timeout
   ✓ 62.102.148.68:443                    163ms
   ✓ 185.220.100.253:9000                 166ms
 2020/04/24 11:53:01 Wrote output to: /dev/stdout
 }}}

 I'm setting this ticket to needs_review because I would like to hear
 cohosh's thoughts on this.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/30794#comment:5>
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