Opened 12 months ago

Last modified 2 months ago

#22489 needs_information defect

Bridge oftenly reports Failed to find node for hop 0 of our path. Discarding this circuit.

Reported by: s7r Owned by:
Priority: Medium Milestone: Tor: 0.3.4.x-final
Component: Core Tor/Tor Version: Tor: 0.3.1.2-alpha
Severity: Normal Keywords: tor-client, tor-bridge, 034-triage-20180328
Cc: gk Actual Points:
Parent ID: Points:
Reviewer: Sponsor:

Description

I have just setup an obfs4 bridge on 0.3.1.2-alpha-dev (git-1763aa058b08a1c5) on FreeBSD. I am using it as a client from another computer and it works well, except I see this warn in the log files of the bridge relay instance:

Jun 03 21:54:41.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 21:58:08.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 22:01:30.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 22:04:37.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 22:07:45.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 22:11:27.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 23:03:04.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 23:06:14.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 23:09:49.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 23:13:19.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 23:16:08.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 23:19:41.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 23:23:48.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 23:27:13.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 23:30:52.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 23:34:55.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 23:38:13.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 23:41:54.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 23:45:18.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 23:48:39.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 23:52:21.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 03 23:55:56.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.

There are a lot of similar messages, no sense to provide all of them since they're all the same.

Child Tickets

Change History (11)

comment:1 Changed 11 months ago by nickm

Keywords: tor-client tor-bridge 030-backport added

comment:2 Changed 11 months ago by gk

Cc: gk added

comment:3 Changed 11 months ago by isis

Status: newneeds_information

You're seeing this in the logs of the bridge relay? Or the client?

That log message is in onion_extend_cpath(origin_circuit_t *circ), which should really only ever be called by a client (or I think also onion services). (Or a bridge which uses #7144, but it's not merged yet.)

comment:4 Changed 11 months ago by s7r

It was logged on the bridge relay. There was no hidden service hosted on the bridge relay instance, just a regular bridge relay setup with obfs4 transport. The odd thing is that no warning / error was logged on the client instance, and the client instance was working with this bridge while the bridge instance was reporting the quoted warnings in log.

comment:5 Changed 11 months ago by arma

Everything is a client. So it sounds like those log lines were referring to the bridge's own circuits that it was making for itself.

comment:6 Changed 11 months ago by s7r

I hit it again few days ago, on the same bridge, 4 times at few minutes interval:

Jun 30 12:28:51.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 30 12:32:27.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 30 12:39:09.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 30 12:42:44.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.
Jun 30 12:46:57.000 [warn] Failed to find node for hop 0 of our path. Discarding this circuit.

The bridge runs in an AS that hosts some other relays. They are in the same /24, but part of the same family. Could the bridge try to pick one of those relays for its own circuits?

comment:7 Changed 9 months ago by s7r

Today (same Tor instance) this changed to:

[warn] Failed to find node for hop #1 of our path. Discarding this circuit.

I am on git master 0.3.2.0-alpha-dev (git-257f50b22fbaf9c9).

comment:8 Changed 8 months ago by s7r

On a more recent master 0.3.2.0-alpha-dev (git-209bfe715cc8c1c5):

Oct 04 11:17:27.000 [notice] Heartbeat: Tor's uptime is 32 days 11:59 hours, with 18 circuits open. I've sent 31.64 GB and received 31.90 GB.
Oct 04 11:17:27.000 [notice] Heartbeat: In the last 6 hours, I have seen 11 unique clients.
Oct 04 17:13:29.000 [warn] Failed to find node for hop #1 of our path. Discarding this circuit.
Oct 04 17:17:27.000 [notice] Heartbeat: Tor's uptime is 32 days 17:59 hours, with 14 circuits open. I've sent 31.78 GB and received 32.05 GB.
Oct 04 17:17:27.000 [notice] Heartbeat: In the last 6 hours, I have seen 11 unique clients.
Oct 04 17:20:24.000 [warn] Failed to find node for hop #1 of our path. Discarding this circuit.
Oct 04 17:28:25.000 [warn] Failed to find node for hop #1 of our path. Discarding this circuit.
Oct 04 17:34:29.000 [warn] Failed to find node for hop #1 of our path. Discarding this circuit.
Oct 04 17:38:36.000 [warn] Failed to find node for hop #1 of our path. Discarding this circuit.
Oct 04 17:45:23.000 [warn] Failed to find node for hop #1 of our path. Discarding this circuit.
Oct 04 17:50:04.000 [warn] Failed to find node for hop #1 of our path. Discarding this circuit.
Oct 04 17:54:06.000 [warn] Failed to find node for hop #1 of our path. Discarding this circuit.
Oct 04 17:58:18.000 [warn] Failed to find node for hop #1 of our path. Discarding this circuit.
Oct 04 18:03:28.000 [warn] Failed to find node for hop #1 of our path. Discarding this circuit.
Oct 04 18:07:39.000 [warn] Failed to find node for hop #1 of our path. Discarding this circuit.
Oct 04 18:11:44.000 [warn] Failed to find node for hop #1 of our path. Discarding this circuit.
Oct 04 20:12:42.000 [warn] Failed to find node for hop #1 of our path. Discarding this circuit.

Again the client that uses this bridge to enter the Tor network didn't notice anything when this occured nor logged anything strange, so can confirm arma's comment:5 - we are looking at bridge's own circuits that it was making for itself.

As I can see this also appears in #8185 - I'll keep an eye out for this after upgrading to latest git master.

comment:9 Changed 4 months ago by nickm

Keywords: 030-backport removed

Remove 030-backport from all open tickets that have it: 0.3.0 is now deprecated.

comment:10 Changed 3 months ago by teor

Milestone: Tor: 0.3.1.x-finalTor: 0.3.4.x-final

These feature and bugfix tickets have no patches. The earliest they will get done is 0.3.4.

comment:11 Changed 2 months ago by nickm

Keywords: 034-triage-20180328 added
Note: See TracTickets for help on using tickets.