[tor-bugs] #33157 [Circumvention/Snowflake]: Client generates SDP with "IN IP4 0.0.0.0", causing proxy to send "client_ip=0.0.0.0" and bridge to send "USERADDR 0.0.0.0:1"
Tor Bug Tracker & Wiki
blackhole at torproject.org
Wed Mar 25 17:59:12 UTC 2020
#33157: Client generates SDP with "IN IP4 0.0.0.0", causing proxy to send
"client_ip=0.0.0.0" and bridge to send "USERADDR 0.0.0.0:1"
-------------------------------------+------------------------
Reporter: dcf | Owner: (none)
Type: defect | Status: new
Priority: Medium | Milestone:
Component: Circumvention/Snowflake | Version:
Severity: Normal | Resolution:
Keywords: | Actual Points:
Parent ID: | Points:
Reviewer: | Sponsor:
-------------------------------------+------------------------
Comment (by dcf):
Since the fix in #33385 on 2020-02-20, only about 20–30% of connections at
the bridge have a meaningful `client_ip`. I believe this is causing us to
undercount clients and/or bandwidth, even though we no longer set
`USERADDR` for those 0.0.0.0 connections. In the absence of `USERADDR`,
tor will use a 127.0.0.1 address, which like 0.0.0.0 is ignored for the
purpose of bandwidth accounting. For instance,
[https://gitweb.torproject.org/tor.git/tree/src/core/mainloop/connection.c?h=tor-0.4.2.7#n3239
record_num_bytes_transferred_impl] calls
[https://gitweb.torproject.org/tor.git/tree/src/core/mainloop/connection.c?h=tor-0.4.2.7#n3039
connection_is_rate_limited] which calls
[https://gitweb.torproject.org/tor.git/tree/src/lib/net/address.c?h=tor-0.4.2.7#n240
tor_addr_is_internal] which returns false for both 0.0.0.0/8 and
127.0.0.0/8. (This is similar to #33693, but on the server, not on the
client.)
Related metrics-team thread: https://lists.torproject.org/pipermail
/metrics-team/2020-March/001139.html
{{{
# zgrep -h client_ip /var/log/tor/snowflake-server.log* | sort
2020/02/20 18:03:47 in the past 86400 s, 476/476 connections had client_ip
2020/02/21 18:03:47 in the past 86400 s, 523/523 connections had client_ip
2020/02/23 23:49:59 in the past 86400 s, 87/330 connections had client_ip
2020/02/24 23:49:59 in the past 86400 s, 128/577 connections had client_ip
2020/02/25 23:49:59 in the past 86400 s, 153/663 connections had client_ip
2020/02/26 23:49:59 in the past 86400 s, 42/239 connections had client_ip
2020/02/27 23:49:59 in the past 86400 s, 158/510 connections had client_ip
2020/02/28 23:49:59 in the past 86400 s, 123/467 connections had client_ip
2020/02/29 23:49:59 in the past 86400 s, 97/451 connections had client_ip
2020/03/01 23:49:59 in the past 86400 s, 117/565 connections had client_ip
2020/03/02 23:49:59 in the past 86400 s, 161/584 connections had client_ip
2020/03/03 23:49:59 in the past 86400 s, 82/325 connections had client_ip
2020/03/04 23:49:59 in the past 86400 s, 111/467 connections had client_ip
2020/03/05 23:49:59 in the past 86400 s, 150/518 connections had client_ip
2020/03/06 23:49:59 in the past 86400 s, 204/768 connections had client_ip
2020/03/07 23:49:59 in the past 86400 s, 175/668 connections had client_ip
2020/03/08 23:49:59 in the past 86400 s, 135/643 connections had client_ip
2020/03/09 23:49:59 in the past 86400 s, 159/634 connections had client_ip
2020/03/10 23:49:59 in the past 86400 s, 198/863 connections had client_ip
2020/03/11 23:49:59 in the past 86400 s, 284/1327 connections had
client_ip
2020/03/12 23:49:59 in the past 86400 s, 117/511 connections had client_ip
2020/03/13 23:49:59 in the past 86400 s, 145/638 connections had client_ip
2020/03/14 23:49:59 in the past 86400 s, 177/808 connections had client_ip
2020/03/15 23:49:59 in the past 86400 s, 349/1470 connections had
client_ip
2020/03/16 23:49:59 in the past 86400 s, 404/1965 connections had
client_ip
2020/03/17 23:49:59 in the past 86400 s, 264/1286 connections had
client_ip
2020/03/18 23:49:59 in the past 86400 s, 279/1155 connections had
client_ip
2020/03/19 23:49:59 in the past 86400 s, 296/1265 connections had
client_ip
2020/03/20 23:49:59 in the past 86400 s, 314/1392 connections had
client_ip
2020/03/21 23:49:59 in the past 86400 s, 290/1025 connections had
client_ip
2020/03/22 23:49:59 in the past 86400 s, 236/637 connections had client_ip
2020/03/23 23:49:59 in the past 86400 s, 199/671 connections had client_ip
2020/03/25 01:37:46 in the past 86400 s, 164/543 connections had client_ip
}}}
{{{
date n d percent
1 2020-02-20 18:03:47 476 476 100.0
2 2020-02-21 18:03:47 523 523 100.0
3 2020-02-23 23:49:59 87 330 26.4
4 2020-02-24 23:49:59 128 577 22.2
5 2020-02-25 23:49:59 153 663 23.1
6 2020-02-26 23:49:59 42 239 17.6
7 2020-02-27 23:49:59 158 510 31.0
8 2020-02-28 23:49:59 123 467 26.3
9 2020-02-29 23:49:59 97 451 21.5
10 2020-03-01 23:49:59 117 565 20.7
11 2020-03-02 23:49:59 161 584 27.6
12 2020-03-03 23:49:59 82 325 25.2
13 2020-03-04 23:49:59 111 467 23.8
14 2020-03-05 23:49:59 150 518 29.0
15 2020-03-06 23:49:59 204 768 26.6
16 2020-03-07 23:49:59 175 668 26.2
17 2020-03-08 23:49:59 135 643 21.0
18 2020-03-09 23:49:59 159 634 25.1
19 2020-03-10 23:49:59 198 863 22.9
20 2020-03-11 23:49:59 284 1327 21.4
21 2020-03-12 23:49:59 117 511 22.9
22 2020-03-13 23:49:59 145 638 22.7
23 2020-03-14 23:49:59 177 808 21.9
24 2020-03-15 23:49:59 349 1470 23.7
25 2020-03-16 23:49:59 404 1965 20.6
26 2020-03-17 23:49:59 264 1286 20.5
27 2020-03-18 23:49:59 279 1155 24.2
28 2020-03-19 23:49:59 296 1265 23.4
29 2020-03-20 23:49:59 314 1392 22.6
30 2020-03-21 23:49:59 290 1025 28.3
31 2020-03-22 23:49:59 236 637 37.0
32 2020-03-23 23:49:59 199 671 29.7
33 2020-03-25 01:37:46 164 543 30.2
}}}
--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/33157#comment:10>
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