[tor-dev] PT bridge reporting significant numbers of <OR> IP addresses after upgrade to 0.4.8.6; Conflux related?

[David Fifield]

The Snowflake bridges do not expose their plain ORPort (they have
`ORPort 127.0.0.1:auto` in torrc), and consequently they have always
reported ≈0 <OR> IP addresses in the bridge-ip-transports line of
bridge-extra-info descriptors, with virtually all connecting IP
addresses being instead attributed to the snowflake transport. (The <OR>
count is low but nonzero, which I have rationalized as tor making some
small number of internal connections, or something.)

I upgraded one of the two Snowflake bridges from 0.4.7.13 to 0.4.8.6 on
2023-09-24. Since then, the number of <OR> IP addresses has been roughly
equal to the number of snowflake IP addresses. The ORPort is still not
exposed; these are not external vanilla bridge users. Did something
change between these versions that might cause PT connections to be
double-counted, once for the transport and once for <OR>?

Here are excerpted bridge-extra-info descriptors from before and after
the version upgrade. Note the bridge-ip-transports lines.

```
@type bridge-extra-info 1.3
extra-info crusty5 91DA221A149007D0FD9E5515F5786C3DD07E4BB0
master-key-ed25519 1y9CAtinlbrhDuYBSOBNiCU9Ck1lcY7LErxnzhtxVks
published 2023-09-19 10:46:08
transport snowflake
bridge-ip-versions v4=13528,v6=1384
bridge-ip-transports <OR>=8,snowflake=14912
```

```
@type bridge-extra-info 1.3
extra-info crusty5 91DA221A149007D0FD9E5515F5786C3DD07E4BB0
master-key-ed25519 1y9CAtinlbrhDuYBSOBNiCU9Ck1lcY7LErxnzhtxVks
published 2023-09-29 17:33:20
transport snowflake
bridge-ip-versions v4=2880,v6=336
bridge-ip-transports <OR>=1632,snowflake=1592
```

Below is a time series for a whole month.
The thing to notice is not the overall decrease in users on 2023-09-20;
that's due to
https://forum.torproject.org/t/problems-with-snowflake-since-2023-09-20-broker-failure-unexpected-error-no-answer/9346.
Rather, the thing to notice is that before 2023-09-24, <OR> ≈ 0; and
after, <OR> ≈ snowflake.

date        <OR> snowflake
2023-08-30     4     45240  ← running 0.4.7.13 here
2023-08-31    21    193412
2023-09-01    30    195647
2023-09-02    40    200405
2023-09-03    40    201730
2023-09-04    42    195097
2023-09-05    35    190842
2023-09-06    30    189694
2023-09-07    26    191524
2023-09-08    35    195833
2023-09-09    32    196244
2023-09-10    27    146972
2023-09-11     6     55491
2023-09-12    18    182519
2023-09-13    17    173536
2023-09-14    21    161396
2023-09-15    21    166379
2023-09-16    16    174350
2023-09-17    17    165063
2023-09-18    23    164734
2023-09-19    32    164075
2023-09-20    23    121623
2023-09-21     2     25268
2023-09-22     0      4314
2023-09-23     0       746
2023-09-24   239       606  ← upgrade to 0.4.8.6 on this day
2023-09-25  1919      1900
2023-09-26  3533      3470
2023-09-27 11919     11687
2023-09-28 20242     19890
2023-09-29 26583     26100
2023-09-30 25929     25400