This is a big-ish patch, but it's very straightforward.  Under this
clang warning, we're not actually allowed to have a global variable
without a previous extern declaration for it.  The cases where we
violated this rule fall into three roughly equal groups:
  * Stuff that should have been static.
  * Stuff that was global but where the extern was local to some
    other C file.
  * Stuff that was only global when built for the unit tests, that
    needed a conditional extern in the headers.

The first two were IMO genuine problems; the last is a wart of how
we build tests.

Closes ticket 15212

George Kadianakis authored Dec 02, 2014 and Nick Mathewson committed Dec 19, 2014

The two statistics are:
 1. number of RELAY cells observed on successfully established
    rendezvous circuits; and
 2. number of .onion addresses observed as hidden-service
    directory.

Both statistics are accumulated over 24 hours, obfuscated by rounding
up to the next multiple of a given number and adding random noise,
and written to local file stats/hidserv-stats.

Notably, no statistics will be gathered on clients or services, but
only on relays.

Because in 95 years, we or our successors will surely care about
enforcing the BSD license terms on this code.  Right?

The /tor/dbg-stability.txt URL was meant to help debug WFU and MTBF
calculations, but nobody was using it.

Fixes #11742.

This improves the accuracy of the function/variable names.

we skip onionskins that came from non-relays, so we're less likely to
run into privacy troubles.

starts to implement ticket 9658.

This prevents bug 8147, where such nodes would accrue points towards
Guard, Fast, HSDir, and so on.

Fixes bug 8147.

In C, we technically aren't supposed to define our own things that
start with an underscore.

This is a purely machine-generated commit.  First, I ran this script
on all the headers in src/{common,or,test,tools/*}/*.h :
==============================

use strict;

my %macros = ();
my %skipped = ();
FILE: for my $fn (@ARGV) {
    my $f = $fn;
    if ($fn !~ /^\.\//) {
	$f = "./$fn";
    }
    $skipped{$fn} = 0;
    open(F, $fn);
    while (<F>) {
	if (/^#ifndef ([A-Za-z0-9_]+)/) {
	    $macros{$fn} = $1;
	    next FILE;
	}
    }
}

print "#!/usr/bin/perl -w -i -p\n\n";
for my $fn (@ARGV) {
    if (! exists $macros{$fn}) {
	print "# No macro known for $fn!\n" if (!$skipped{$fn});
	next;
    }
    if ($macros{$fn} !~ /_H_?$/) {
	print "# Weird macro for $fn...\n";
    }
    my $goodmacro = uc $fn;
    $goodmacro =~ s#.*/##;
    $goodmacro =~ s#[\/\-\.]#_#g;
    print "s/(?<![A-Za-z0-9_])$macros{$fn}(?![A-Za-z0-9_])/TOR_${goodmacro}/g;\n"
}
==============================

It produced the following output, which I then re-ran on those same files:

==============================

s/(?<![A-Za-z0-9_])_TOR_ADDRESS_H(?![A-Za-z0-9_])/TOR_ADDRESS_H/g;
s/(?<![A-Za-z0-9_])_TOR_AES_H(?![A-Za-z0-9_])/TOR_AES_H/g;
s/(?<![A-Za-z0-9_])_TOR_COMPAT_H(?![A-Za-z0-9_])/TOR_COMPAT_H/g;
s/(?<![A-Za-z0-9_])_TOR_COMPAT_LIBEVENT_H(?![A-Za-z0-9_])/TOR_COMPAT_LIBEVENT_H/g;
s/(?<![A-Za-z0-9_])_TOR_CONTAINER_H(?![A-Za-z0-9_])/TOR_CONTAINER_H/g;
s/(?<![A-Za-z0-9_])_TOR_CRYPTO_H(?![A-Za-z0-9_])/TOR_CRYPTO_H/g;
s/(?<![A-Za-z0-9_])TOR_DI_OPS_H(?![A-Za-z0-9_])/TOR_DI_OPS_H/g;
s/(?<![A-Za-z0-9_])_TOR_MEMAREA_H(?![A-Za-z0-9_])/TOR_MEMAREA_H/g;
s/(?<![A-Za-z0-9_])_TOR_MEMPOOL_H(?![A-Za-z0-9_])/TOR_MEMPOOL_H/g;
s/(?<![A-Za-z0-9_])TOR_PROCMON_H(?![A-Za-z0-9_])/TOR_PROCMON_H/g;
s/(?<![A-Za-z0-9_])_TOR_TORGZIP_H(?![A-Za-z0-9_])/TOR_TORGZIP_H/g;
s/(?<![A-Za-z0-9_])_TOR_TORINT_H(?![A-Za-z0-9_])/TOR_TORINT_H/g;
s/(?<![A-Za-z0-9_])_TOR_LOG_H(?![A-Za-z0-9_])/TOR_TORLOG_H/g;
s/(?<![A-Za-z0-9_])_TOR_TORTLS_H(?![A-Za-z0-9_])/TOR_TORTLS_H/g;
s/(?<![A-Za-z0-9_])_TOR_UTIL_H(?![A-Za-z0-9_])/TOR_UTIL_H/g;
s/(?<![A-Za-z0-9_])_TOR_BUFFERS_H(?![A-Za-z0-9_])/TOR_BUFFERS_H/g;
s/(?<![A-Za-z0-9_])_TOR_CHANNEL_H(?![A-Za-z0-9_])/TOR_CHANNEL_H/g;
s/(?<![A-Za-z0-9_])_TOR_CHANNEL_TLS_H(?![A-Za-z0-9_])/TOR_CHANNELTLS_H/g;
s/(?<![A-Za-z0-9_])_TOR_CIRCUITBUILD_H(?![A-Za-z0-9_])/TOR_CIRCUITBUILD_H/g;
s/(?<![A-Za-z0-9_])_TOR_CIRCUITLIST_H(?![A-Za-z0-9_])/TOR_CIRCUITLIST_H/g;
s/(?<![A-Za-z0-9_])_TOR_CIRCUITMUX_EWMA_H(?![A-Za-z0-9_])/TOR_CIRCUITMUX_EWMA_H/g;
s/(?<![A-Za-z0-9_])_TOR_CIRCUITMUX_H(?![A-Za-z0-9_])/TOR_CIRCUITMUX_H/g;
s/(?<![A-Za-z0-9_])_TOR_CIRCUITUSE_H(?![A-Za-z0-9_])/TOR_CIRCUITUSE_H/g;
s/(?<![A-Za-z0-9_])_TOR_COMMAND_H(?![A-Za-z0-9_])/TOR_COMMAND_H/g;
s/(?<![A-Za-z0-9_])_TOR_CONFIG_H(?![A-Za-z0-9_])/TOR_CONFIG_H/g;
s/(?<![A-Za-z0-9_])TOR_CONFPARSE_H(?![A-Za-z0-9_])/TOR_CONFPARSE_H/g;
s/(?<![A-Za-z0-9_])_TOR_CONNECTION_EDGE_H(?![A-Za-z0-9_])/TOR_CONNECTION_EDGE_H/g;
s/(?<![A-Za-z0-9_])_TOR_CONNECTION_H(?![A-Za-z0-9_])/TOR_CONNECTION_H/g;
s/(?<![A-Za-z0-9_])_TOR_CONNECTION_OR_H(?![A-Za-z0-9_])/TOR_CONNECTION_OR_H/g;
s/(?<![A-Za-z0-9_])_TOR_CONTROL_H(?![A-Za-z0-9_])/TOR_CONTROL_H/g;
s/(?<![A-Za-z0-9_])_TOR_CPUWORKER_H(?![A-Za-z0-9_])/TOR_CPUWORKER_H/g;
s/(?<![A-Za-z0-9_])_TOR_DIRECTORY_H(?![A-Za-z0-9_])/TOR_DIRECTORY_H/g;
s/(?<![A-Za-z0-9_])_TOR_DIRSERV_H(?![A-Za-z0-9_])/TOR_DIRSERV_H/g;
s/(?<![A-Za-z0-9_])_TOR_DIRVOTE_H(?![A-Za-z0-9_])/TOR_DIRVOTE_H/g;
s/(?<![A-Za-z0-9_])_TOR_DNS_H(?![A-Za-z0-9_])/TOR_DNS_H/g;
s/(?<![A-Za-z0-9_])_TOR_DNSSERV_H(?![A-Za-z0-9_])/TOR_DNSSERV_H/g;
s/(?<![A-Za-z0-9_])TOR_EVENTDNS_TOR_H(?![A-Za-z0-9_])/TOR_EVENTDNS_TOR_H/g;
s/(?<![A-Za-z0-9_])_TOR_GEOIP_H(?![A-Za-z0-9_])/TOR_GEOIP_H/g;
s/(?<![A-Za-z0-9_])_TOR_HIBERNATE_H(?![A-Za-z0-9_])/TOR_HIBERNATE_H/g;
s/(?<![A-Za-z0-9_])_TOR_MAIN_H(?![A-Za-z0-9_])/TOR_MAIN_H/g;
s/(?<![A-Za-z0-9_])_TOR_MICRODESC_H(?![A-Za-z0-9_])/TOR_MICRODESC_H/g;
s/(?<![A-Za-z0-9_])_TOR_NETWORKSTATUS_H(?![A-Za-z0-9_])/TOR_NETWORKSTATUS_H/g;
s/(?<![A-Za-z0-9_])_TOR_NODELIST_H(?![A-Za-z0-9_])/TOR_NODELIST_H/g;
s/(?<![A-Za-z0-9_])_TOR_NTMAIN_H(?![A-Za-z0-9_])/TOR_NTMAIN_H/g;
s/(?<![A-Za-z0-9_])_TOR_ONION_H(?![A-Za-z0-9_])/TOR_ONION_H/g;
s/(?<![A-Za-z0-9_])_TOR_OR_H(?![A-Za-z0-9_])/TOR_OR_H/g;
s/(?<![A-Za-z0-9_])_TOR_POLICIES_H(?![A-Za-z0-9_])/TOR_POLICIES_H/g;
s/(?<![A-Za-z0-9_])_TOR_REASONS_H(?![A-Za-z0-9_])/TOR_REASONS_H/g;
s/(?<![A-Za-z0-9_])_TOR_RELAY_H(?![A-Za-z0-9_])/TOR_RELAY_H/g;
s/(?<![A-Za-z0-9_])_TOR_RENDCLIENT_H(?![A-Za-z0-9_])/TOR_RENDCLIENT_H/g;
s/(?<![A-Za-z0-9_])_TOR_RENDCOMMON_H(?![A-Za-z0-9_])/TOR_RENDCOMMON_H/g;
s/(?<![A-Za-z0-9_])_TOR_RENDMID_H(?![A-Za-z0-9_])/TOR_RENDMID_H/g;
s/(?<![A-Za-z0-9_])_TOR_RENDSERVICE_H(?![A-Za-z0-9_])/TOR_RENDSERVICE_H/g;
s/(?<![A-Za-z0-9_])_TOR_REPHIST_H(?![A-Za-z0-9_])/TOR_REPHIST_H/g;
s/(?<![A-Za-z0-9_])_TOR_REPLAYCACHE_H(?![A-Za-z0-9_])/TOR_REPLAYCACHE_H/g;
s/(?<![A-Za-z0-9_])_TOR_ROUTER_H(?![A-Za-z0-9_])/TOR_ROUTER_H/g;
s/(?<![A-Za-z0-9_])_TOR_ROUTERLIST_H(?![A-Za-z0-9_])/TOR_ROUTERLIST_H/g;
s/(?<![A-Za-z0-9_])_TOR_ROUTERPARSE_H(?![A-Za-z0-9_])/TOR_ROUTERPARSE_H/g;
s/(?<![A-Za-z0-9_])TOR_ROUTERSET_H(?![A-Za-z0-9_])/TOR_ROUTERSET_H/g;
s/(?<![A-Za-z0-9_])TOR_STATEFILE_H(?![A-Za-z0-9_])/TOR_STATEFILE_H/g;
s/(?<![A-Za-z0-9_])_TOR_STATUS_H(?![A-Za-z0-9_])/TOR_STATUS_H/g;
s/(?<![A-Za-z0-9_])TOR_TRANSPORTS_H(?![A-Za-z0-9_])/TOR_TRANSPORTS_H/g;
s/(?<![A-Za-z0-9_])_TOR_TEST_H(?![A-Za-z0-9_])/TOR_TEST_H/g;
s/(?<![A-Za-z0-9_])_TOR_FW_HELPER_H(?![A-Za-z0-9_])/TOR_TOR_FW_HELPER_H/g;
s/(?<![A-Za-z0-9_])_TOR_FW_HELPER_NATPMP_H(?![A-Za-z0-9_])/TOR_TOR_FW_HELPER_NATPMP_H/g;
s/(?<![A-Za-z0-9_])_TOR_FW_HELPER_UPNP_H(?![A-Za-z0-9_])/TOR_TOR_FW_HELPER_UPNP_H/g;
==============================

MSVC warns if you declare a function as having a "int foo" argument
and then implement it with a "const int foo" argument, even though
the latter "const" is not a part of the function's interface.

Fix for bug 3296.

Sebastian Hahn authored Oct 07, 2011 and Nick Mathewson committed Oct 21, 2011

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.

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.

It is important to verify the uptime claim of a relay instead of just
trusting it, otherwise it becomes too easy to blackhole a specific
hidden service. rephist already has data available that we can use here.

Bugfix on 0.2.0.10-alpha.

rransom noticed that a change of ORPort is just as bad as a change of IP
address from a client's perspective, because both mean that the relay is
not available to them while the new information hasn't propagated.
Change the bug1035 fix accordingly.

Also make sure we don't log a bridge's IP address (which might happen
when we are the bridge authority).

calculation purposes.

Our checks that we don't exceed the 50 KB size limit of extra-info
descriptors apparently failed. This patch fixes these checks and reserves
another 250 bytes for appending the signature. Fixes bug 2183.

Also remove some #if 0'd code from the unit tests for buffers. The
code was killed in e6794e58 (5 years
ago), and is now broken anyways.

With this patch we stop scheduling when we should write statistics using a
single timestamp in run_scheduled_events(). Instead, we remember when a
statistics interval starts separately for each statistic type in geoip.c
and rephist.c. Every time run_scheduled_events() tries to write stats to
disk, it learns when it should schedule the next such attempt.

This patch also enables all statistics to be stopped and restarted at a
later time.

This patch comes with a few refactorings, some of which were not easily
doable without the patch.