This is safe, because no entry_guard_t ever outlives its
guard_selection_t.
I want this because now that multiple guard selections can be active
during one tor session, we should make sure that any information we
register about guards is with respect to the selection that they came
from.
Currently, this code doesn't actually have the contexts behave
differently, (except for the legacy context), but it does switch
back and forth between them nicely.
If a guard becomes primary as a result of confirming it, consider
the circuit through that guard as a primary circuit.
Also, note open questions on behavior when confirming nonprimary guards
Some of these will get torrc options to override them too; this
is just the mechanical conversion.
Also, add documentation for a couple of undocumented (but now used)
parameters.
Act I.
" But that I am forbid
To tell the secrets of my prison-house,
I could a tale unfold..."
Here's the bug: sometimes, rend_cache/store_v2_desc_as_client would
say:
"Dec 15 08:31:26.147 [warn] rend_cache_store_v2_desc_as_client():
Bug: Couldn't decode base32 [scrubbed] for descriptor id. (on Tor
0.3.0.0-alpha-dev 4098bfa260)"
When we merged ade5005853 back in 0.2.8.1-alpha, we added that
test: it mangles the hidden service ID for a hidden service, and
ensures that when the descriptor ID doesn't match the descriptor's
key, we don't store the descriptor.
How did it mangle the descriptor ID? By doing
desc_id_base32[0]++;
So, if the hidden service ID started with z or 7, we'd wind up with an
invalid base32 string, and get the warning. And if it started with
any other character, we wouldn't.
That there is part 1 of the bug: in 2/32 cases, we'd get a BUG
warning. But we wouldn't display it, since warnings weren't shown
from the unit tests.
Act II.
"Our indiscretion sometime serves us well,
When our deep plots do pall"
Part two: in 0.2.9.3-alpha, for part of #19999, we turned on BUG
warnings in the unit tests, so that we'd actually start seeing them.
At this point we also began to consider each BUG warning that made
it through the unit tests to be an actual bug. So before this
point, we wouldn't actually notice anything happening in those 2/32
cases.
So, at this point it was a nice random _visible_ bug.
Act III.
"Our thoughts are ours, their ends none of our own"
In acbb60cd63, which was part of my prop220 work, I
changed how RSA key generation worked in the unit tests. While
previously we'd use pre-made RSA keys in some cases, this change
made us use a set of pregenerated RSA keys for _all_ 1024 or 2048
keys, and to return them in a rotation when Tor tried to generate a
key.
And now we had the heisenbug: anything that affected the number of
pregenerated keys that we had yielded before reaching
rend_cache/store_v2_desc_as_client would make us return a different
key, which would give us a different base32 ID, which would make the
bug occur, or not. So as we added or removed test cases, the bug
might or might not happen.
So yeah. Don't mangle a base32 ID like that. Do it this way instead.
The new HS circuitmap API replaces old public functions as follows:
circuit_clear_rend_token -> hs_circuitmap_remove_circuit
circuit_get_rendezvous -> hs_circuitmap_get_rend_circ
circuit_get_intro_point -> hs_circuitmap_get_intro_circ_v2
circuit_set_rendezvous_cookie -> hs_circuitmap_register_rend_circ
circuit_set_intro_point_digest -> hs_circuitmap_register_intro_circ_v2
This commit also removes the old rendinfo code that is now unused.
It also fixes the broken rendinfo unittests.
The HS circuitmap is a hash table that maps introduction and rendezvous
tokens to specific circuits such that given a token it's easy to find
the corresponding circuit. It supports rend circuits and v2/v3 intro
circuits.
It will be used by the prop224 ESTABLISH_INTRO code to register and
lookup v3 introduction circuits.
The next commit after this removes the old code and fixes the unittests.
Please consult both commits while reviewing functionality differences
between the old and new code. Let me know if you want this rebased
differently :)
WRT architectural differences, this commit removes the rendinfo pointer
from or_circuit_t. It then adds an hs_token_t pointer and a hashtable
node for the HS circuitmap. IIUC, this adds another pointer to the
weight of or_circuit_t. Let me know if you don't like this, or if you
have suggestions on improving it.
