pt-spec says:
```
If the encoded argument list is less than 255 bytes in
length, the "PLEN" field must be set to "1" and the "PASSWD"
field must contain a single NUL character.
```
This is a very silly thing to say, but some PTs enforce it.
Fixes#676.
This commit makes the `ChanBuilder` type in `tor-chanmgr` usable by
consumers outside of that crate, like the doc comment for
`ChannelFactory` says you need to be able to do in order to turn your
`TransportHelper` into something useful.
As part of doing this, the `event_sender` its constructor takes needed
to be dealt with, since it was a crate-internal type that came from
inside the `ChanMgr`.
Enter `BootstrapReporter`: an opaque wrapper around that sender, now
provided as an additional argument to
`ChannelFactory::connect_via_transport`. You can now construct a
`ChanBuilder` outside this crate, and it'll still be able to report its
bootstrap status by unwrapping this new type that's threaded through
from the `ChanMgr`. (This was a fair deal of manually threading the type
through all the layers in this crate!)
Note that you cannot implement bootstrap updating using something that
isn't `ChanBuilder` yet due to the type being entirely opaque (but, of
course, we can figure out exactly what API the reporter should have
later, and add that capability in).
This commit implements `PtMgr`, a pluggable transport manager
responsible for keeping track of spawned PTs and spawning them to
satisfy client requests on demand.
It does this in two parts: the `PtMgr` type exported to the rest of the
code, and the background `PtReactor` that actually does the spawning;
this design ensures that only one attempt to spawn a PT is active at a
time, and will prove useful later for implementing e.g. timeouts.
A few changes were necessary to the rest of the code in order to make
this all work out. Namely:
- `TransportRegistry`'s API didn't make any sense for two reasons:
- It wasn't feasible for implementors to implement `ChannelFactory`,
since that'd require constructing a `ChanBuilder` (which requires a
bootstrap reporting event sender).
- Treating the PT manager as a registry is over-general; it's only
necessary for it to spawn pluggable transports, so saddling it with
other concerns didn't make any sense.
- (It's possible to get extensibility for arbitrary user customization
by just letting the user swap in a new `ChannelFactory`, anyway.)
- Therefore, the `PtMgr` implements the new `AbstractPtMgr` trait, which
is far more narrowly focused; this only exists to solve a dependency
loop, and is documented as such.
- This provides a `TransportHelper` instead of a `ChannelFactory`.
Enums with variants conditional on cargo features must be
non-exhaustive, because cargo features are supposed to be additive,
meaning that enabling a feature (which might happen due to some random
distant thing) ought not to break things using that enum.
There were surprisingly few places to fix this.
This
1. Makes the errors smaller (in the case of Io's PtTargetAddr;
ChannelBuild's addresses are already indirected in a Vec).
2. Redacts (currently, scrubs) the PtTargetAddr and SocketAddr
when safe logging is enabled
These are the remaining error variants in tor-chanmgr that contain
information that should become sensitive as part of bridge support.
This
1. Makes the errors smaller
2. Redacts (currently, scrubs) the chantarget when safe logging is enabled
This commit doesn't treat other should-be-sensitive inforemation in
errors just yet. That will come in a moment.
We will want the freedom to replace this, so it needs to go behind a
lock. We need to be able to Clone it cheaply now, so we're using an
Arc instead of a Box.
It doesn't make much sense to have the pluggable transport manager be a
registry, so replace its interface with a more narrowly defined, less generic
version.
Other changes:
- instead of returning a &-reference, it returns an owned Arc, which
should make the ptmgr easier to implement while allowing efficient
reuse
- provision for error handling is added, but will probably be revised in
a future commit pending discussion
- tor-ptmgr code that would generate warnings as a result of this change
is temporarily removed
This is a split out version of arti!886, intended so work on arti#659
can proceed.
We're doing this because the type now holds "all the mutable state
in a ChanMgr", not just the map.
This is a pure renaming; no documentation has been updated.
Part of #606.
Nick Mathewson
eta
Emil Engler
Ian Jackson