There is a bug causing busy loops in Libevent and infinite loops in
the Shadow simulator. A connection that is marked for close, wants
to flush, is held open to flush, but is rate limited (the token
bucket is empty) triggers the bug.
This commit fixes the bug. Details are below.
This currently happens on read and write callbacks when the active
socket is marked for close. In this case, Tor doesn't actually try
to complete the read or write (it returns from those methods when
marked), but instead tries to clear the connection with
conn_close_if_marked(). Tor will not close a marked connection that
contains data: it must be flushed first. The bug occurs when this
flush operation on the marked connection can not occur because the
connection is rate-limited (its write token bucket is empty).
The fix is to detect when rate limiting is preventing a marked
connection from properly flushing. In this case, it should be
flagged as read/write_blocked_on_bandwidth and the read/write events
de-registered from Libevent. When the token bucket gets refilled, it
will check the associated read/write_blocked_on_bandwidth flag, and
add the read/write event back to Libevent, which will cause it to
fire. This time, it will be properly flushed and closed.
The reason that both read and write events are both de-registered
when the marked connection can not flush is because both result in
the same behavior. Both read/write events on marked connections will
never again do any actual reads/writes, and are only useful to
trigger the flush and close the connection. By setting the
associated read/write_blocked_on_bandwidth flag, we ensure that the
event will get added back to Libevent, properly flushed, and closed.
Why is this important? Every Shadow event occurs at a discrete time
instant. If Tor does not properly deregister Libevent events that
fire but result in Tor essentially doing nothing, Libevent will
repeatedly fire the event. In Shadow this means infinite loop,
outside of Shadow this means wasted CPU cycles.
Also, try to resolve some doxygen issues. First, define a magic
"This is doxygen!" macro so that we take the correct branch in
various #if/#else/#endifs in order to get the right documentation.
Second, add in a few grouping @{ and @} entries in order to get some
variables and fields to get grouped together.
Previously, we skipped everything that got invoked from
options_init_from_torrc. But some of the stuff in
options_act_reversible and options_act is actually important, like
reopening the logs.
Now, a SIGHUP always makes the effects of an options_set() happen,
even though the options haven't changed.
Fix for bug 5095; bugfix on 0.2.1.9-alpha, which introduced
__ReloadTorrcOnSIGHUP.
This commit is completely mechanical; I used this perl script to make it:
#!/usr/bin/perl -w -i.bak -p
if (/^\s*\#/) {
s/MS_WINDOWS/_WIN32/g;
s/\bWIN32\b/_WIN32/g;
}
Preprocessor directives should not be put inside the arguments
of a macro. This is not supported on older GCC releases (< 3.3)
thus broke compilation on Haiku (running gcc2).
This code handles the new ORPort options, and incidentally makes all
remaining port types use the new port configuration systems.
There are some rough edges! It doesn't do well in the case where your
Address says one thing but you say to Advertise another ORPort. It
doesn't handle AllAddrs. It doesn't actually advertise anything besides
the first listed advertised IPv4 ORPort and DirPort. It doesn't do
port forwarding to them either.
It's not tested either, it needs more documentation, and it probably
forgets to put the milk back in the refrigerator.
Some controllers want this so they can mess with Tor's configuration
for a while via the control port before actually letting Tor out of
the house.
We do this with a new DisableNetwork option, that prevents Tor from
making any outbound connections or binding any non-control
listeners. Additionally, it shuts down the same functionality as
shuts down when we are hibernating, plus the code that launches
directory downloads.
To make sure I didn't miss anything, I added a clause straight to
connection_connect, so that we won't even try to open an outbound
socket when the network is disabled. In my testing, I made this an
assert, but since I probably missed something, I've turned it into a
BUG warning for testing.
We used to do init_keys() if DynamicDHGroups changed after a HUP, so
that the dynamic DH modulus was stored on the disk. Since we are now
doing dynamic DH modulus storing in crypto.c, we can simply initialize
the TLS context and be good with it.
Introduce a new function router_initialize_tls_context() which
initializes the TLS context and use it appropriately.
When running with IOCP, we are in theory able to use userspace-
allocated buffers to avoid filling up the stingy amount of kernel
space allocated for sockets buffers.
The bufferevent_async implementation in Libevent provides this
ability, in theory. (There are likely to be remaining bugs). This
patch adds a new option that, when using IOCP bufferevents, sets
each socket's send and receive buffers to 0, so that we should use
this ability.
When all the bugs are worked out here, if we are right about bug 98,
this might solve or mitigate bug 98.
This option is experimental and will likely require lots of testing
and debugging.
This is used for the bridge authority currently, to get a better
intuition on how many descriptors are actually fetched from it and how
many fetches happen in total.
Implements ticket 4200.
With managed proxies you would always get the error message:
"You have a Bridge line using the X pluggable transport, but there
doesn't seem to be a corresponding ClientTransportPlugin line."
because the check happened directly after parse_client_transport_line()
when managed proxies were not fully configured and their transports
were not registered.
The fix is to move the validation to run_scheduled_events() and make
sure that all managed proxies are configured first.
Right now we only force a new descriptor upload every 18 hours.
This can make servers become unlisted if they upload a descriptor at
time T which the authorities reject as being "too similar" to one
they uploaded before. Nothing will actually make the server upload a
new descriptor later on, until another 18 hours have passed.
This patch changes the upload behavior so that the 18 hour interval
applies only when we're listed in a live consensus with a descriptor
published within the last 18 hours. Otherwise--if we're not listed
in the live consensus, or if we're listed with a publication time
over 18 hours in the past--we upload a new descriptor every 90
minutes.
This is an attempted bugfix for #3327. If we merge it, it should
obsolete #535.
Conflicts:
src/or/connection.c
src/or/connection_edge.c
src/or/connection_edge.h
src/or/dnsserv.c
Some of these were a little tricky, since they touched code that
changed because of the prop171 fixes.
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.
* Add some utility transport functions in circuitbuild.[ch] so that we
can use them from pt.c.
* Make the accounting system consider traffic coming from proxies.
* Make sure that we only fetch bridge descriptors when all the
transports are configured.
This lets us make a lot of other stuff const, allows the compiler to
generate (slightly) better code, and will make me get slightly fewer
patches from folks who stick mutable stuff into or_options_t.
const: because not every input is an output!
