Now that formatting the buffer-stats string is separate from writing
it to disk, we can also decouple the logic to extract stats from
circuits and finally write some unit tests for the history code.
The new rep_hist_format_buffer_stats() generates a buffer-stats string
that rep_hist_buffer_stats_write() writes to disk. All the state
changing (e.g., resetting the buffer-stats history and initializing
the next measurement interval) takes place in
rep_hist_buffer_stats_write(). That allows us to finally test the
buffer-stats code better.
So far, if we didn't see a single circuit, we refrained from
generating a cell-stats string and logged a warning. Nobody will
notice the warning, and people will wonder why there's no cell-stats
string in the extra-info descriptor. The better behavior is to
generate a cell-stats string with all zeros.
Right now, we append statistics to files in the stats/ directory for
half of the statistics, whereas we overwrite these files for the other
half. In particular, we append buffer, dirreq, and entry stats and
overwrite exit, connection, and bridge stats.
Appending to files was useful when we didn't include stats in extra-info
descriptors, because otherwise we'd have to copy them away to prevent
Tor from overwriting them.
But now that we include statistics in extra-info descriptors, it makes
no sense to keep the old statistics forever. We should change the
behavior to overwriting instead of appending for all statistics.
Implements #2930.
Previously we'd just looked at the connection type, but that's
always CONN_TYPE_AP. Instead, we should be looking at the type of
the listener that created the connection.
Spotted by rransom; fixes bug 3636.
We'll still need to tweak it so that it looks for includes and
libraries somewhere more sensible than "where we happened to find
them on Erinn's system"; so that tests and tools get built too;
so that it's a bit documented; and so that we actually try running
the output.
Work done with Erinn Clark.
Previously, if tor_addr_to_str() returned NULL, we would reuse the
last value returned by fmt_addr(). (This could happen if we were
erroneously asked to format an AF_UNSPEC address.) Now instead we
return "???".
The conflicts are with the proposal 171 circuit isolation code, and
they're all trivial: they're just a matter of both branches adding
some unrelated code in the same places.
Conflicts:
src/or/circuituse.c
src/or/connection.c
The problem was that we weren't initializing want_length to 0 before
calling parse_socks() the first time, so it looked like we were
risking an infinite loop when in fact we were safe.
Fixes 3615; bugfix on 0.2.3.2-alpha.
Back when I added this logic in 20c0581a79, the rule was that whenever
a circuit finished building, we cleared its isolation info. I did that
so that we would still use the circuit even if all the streams that
had previously led us to tentatively set its isolation info had closed.
But there were problems with that approach: We could pretty easily get
into a case where S1 had led us to launch C1 and S2 had led us to
launch C2, but when C1 finished, we cleared its isolation and attached
S2 first. Since C2 was still marked in a way that made S1
unattachable to it, we'd then launch another circuit needlessly.
So instead, we try the following approach now: when a circuit is done
building, we try to attach streams to it. If it remains unused after
we try attaching streams, then we clear its isolation info, and try
again to attach streams.
Thanks to Sebastian for helping me figure this out.
One-hop dirconn streams all share a session group, and get the
ISO_SESSIONGRP flag: they may share circuits with each other and
nothing else.
Anonymized dirconn streams get a new internal-use-only ISO_STREAM
flag: they may not share circuits with anything, including each other.
The new candidate rule, which arma suggested and I like, is that
the original address as received from the client connection or as
rewritten by the controller is the address that counts.
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.
