On 2/23/13 11:20 PM, Rob Jansen wrote:
On Feb 23, 2013 4:22 PM, "Karsten Loesing" karsten@torproject.org wrote:
Your understanding of n_circ_id and p_circ_id matches mine, but are you sure there's a UID for circuits other than origin circuits? I think you mean origin_circuit_t->global_identifier. But there's no such field for or_circuit_t or circuit_t. Or do you mean something else?
Ok. Though I thought my original patch moved the global Id to the base circuit struct. Perhaps I didn't. Anyway, I'm not sure it matters...
Your original patch did move the ID to circuit_t, but I thought we wanted to avoid numbering non-origin circuits (mostly because that affects relays in non-TestingTorNetwork mode and could lead to busy relays running out of IDs at some point), which is why I took this change out.
Also, even if we moved the field to circuit_t, the new CELL_STATS events would be the only ones using these UIDs, because all other events are for origin circuits only. I don't see how these IDs would help us. We never learn what UID the next or previous node in a circuit picks for a given circuit.
tl;dr: I _think_ it's possible to reconstruct circuits from ORCONN and CELL_STATS events as they are currently specified in proposal 218.
Great, but do we really expect every Tor controller parser to get this right? It seems complicated enough that there should be an easier way. Maybe it's just wishful thinking on my part.
I agree that reconstructing circuits from ORCONN and CELL_STATS events is far from trivial. I don't really see how to make it simpler though.
From an earlier mail in this thread:
Finally, Rob, should I look into CIRC_BW events you suggested a while ago? If yes, what did you have in mind how that event would look like, and when/by whom would it be emitted?
If we want to do this, it would likely be an aggregation of all STREAM_BW events for a circuit, but only during the time when those streams belonged to that circuit. I don't think it makes sense to emit it for every STREAM_BW event though, so what if we aggregate and emit it once per second? A format similar to the STREAM_BW format should work fine.
Done. I specified and implemented such a CIRC_BW event.
Here's the updated proposal 218 (Nick, please don't merge this yet):
https://gitweb.torproject.org/user/karsten/torspec.git/blob/refs/heads/propo...
Here's the tor branch:
https://gitweb.torproject.org/karsten/tor.git/shortlog/refs/heads/morestats3
Here's a Shadow log file containing all new events:
https://people.torproject.org/~karsten/volatile/scallion.log.gz
Here's the Java program that I used to parse the Shadow log file:
https://people.torproject.org/~karsten/volatile/ParseProposal218Events.java
And finally, here's the output, which should be easier to understand now:
https://people.torproject.org/~karsten/volatile/scallion.txt
Search for "Circuit [fileclient-60.1.0.0]:14" to find the circuit I mentioned earlier in this thread.
Can you review the proposal changes and tell me if they make sense to you?
Best, Karsten
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Karsten Loesing