This is mainly meant as a way to keep clients from accidentally
DOSing themselves by (e.g.) enabling IsolateDestAddr or
IsolateDestPort on a port that they use for HTTP.
Our old "do we need to launch a circuit for stream S" logic was,
more or less, that if we had a pending circuit that could handle S,
we didn't need to launch a new one.
But now that we have streams isolated from one another, we need
something stronger here: It's possible that some pending C can
handle either S1 or S2, but not both.
This patch reuses the existing isolation logic for a simple
solution: when we decide during circuit launching that some pending
C would satisfy stream S1, we "hypothetically" mark C as though S1
had been connected to it. Now if S2 is incompatible with S1, it
won't be something that can attach to C, and so we'll launch a new
stream.
When the circuit becomes OPEN for the first time (with no streams
attached to it), we reset the circuit's isolation status. I'm not
too sure about this part: I wanted some way to be sure that, if all
streams that would have used a circuit die before the circuit is
done, the circuit can still get used. But I worry that this
approach could also lead to us launching too many circuits. Careful
thought needed here.
This is the meat of proposal 171: we change circuit_is_acceptable()
to require that the connection is compatible with every connection
that has been linked to the circuit; we update circuit_is_better to
prefer attaching streams to circuits in the way that decreases the
circuits' usefulness the least; and we update link_apconn_to_circ()
to do the appropriate bookkeeping.
The "nym epoch" of a stream is defined as the number of times that
NEWNYM had been called before the stream was opened. All streams
are isolated by nym epoch.
This feature should be redundant with existing signewnym stuff, but
it provides a good belt-and-suspenders way for us to avoid ever
letting any circuit type bypass signewnym.
This patch adds fields to track how streams should be isolated, and
ensures that those fields are set correctly. It also adds fields to
track what streams can go on a circuit, and adds functions to see
whether a streams can go on a circuit and update the circuit
accordingly. Those functions aren't yet called.
Proposal 171 gives us a new syntax for parsing client port options.
You can now have as many FooPort options as you want (for Foo in
Socks, Trans, DNS, NATD), and they can have address:port arguments,
and you can specify the level of isolation on those ports.
Additionally, this patch refactors the client port parsing logic to
use a new type, port_cfg_t. Previously, ports to be bound were
half-parsed in config.c, and later re-parsed in connection.c when
we're about to bind them. Now, parsing a port means converting it
into a port_cfg_t, and binding it uses only a port_cfg_t, without
needing to parse the user-provided strings at all.
We should do a related refactoring on other port types. For
control ports, that'll be easy enough. For ORPort and DirPort,
we'll want to do this when we solve proposal 118 (letting servers
bind to and advertise multiple ports).
This implements tickets 3514 and 3515.
This adds a little code complexity: we need to remember for each
node whether it supports the right feature, and then check for each
connection whether it's exiting at such a node. We store this in a
flag in the edge_connection_t, and set that flag at link time.
- Conform to make check-spaces
- Build without warnings from passing size_t to %d
- Use connection_get_inbuf_len(), not buf_datalen (otherwise bufferevents
won't work).
- Don't log that we're using this feature at warn.
Previously we were using router_get_by_id(foo) to test "do we have a
descriptor that will let us make an anonymous circuit to foo". But
that isn't right for microdescs: we should have been using node_t.
Fixes bug 3601; bugfix on 0.2.3.1-alpha.
Instead, use compare_tor_addr_to_node_policy everywhere.
One advantage of this is that compare_tor_addr_to_node_policy can
better distinguish 0.0.0.0 from "unknown", which caused a nasty bug
with microdesc users.
Previously, we had an issue where we'd treat an unknown address as
0, which turned into "0.0.0.0", which looked like a rejected
address. This meant in practice that as soon as we started doing
comparisons of unknown uint32 addresses to short policies, we'd get
'rejected' right away. Because of the circumstances under which
this would be called, it would only happen when we had local DNS
cached entries and we were looking to launch new circuits.
Rationale: right now there seems to be no way for our bootstrap
status to dip under 100% once it has reached 100%. Thus, recording
broken connections after that point is useless, and wastes memory.
If at some point in the future we allow our bootstrap level to go
backwards, then we should change this rule so that we disable
recording broken connection states _as long as_ the bootstrap status
is 100%.
- We were reporting the _bottom_ N failing states, not the top N.
- With bufferevents enabled, we logged all TLS states as being "in
bufferevent", which isn't actually informative.
- When we had nothing to report, we reported nothing too loudly.
- Also, we needed documentation.
