When I merged the fix for #7351, and implemented proposal 214 (4-byte
circuit IDs), I forgot to add a changes file.  Later, we never noticed
that it didn't have one.

Resolves ticket #11555.  Thanks to cypherpunks for noticing this was
missing.

This is a cherry-pick of 75e10f58 into
the master branch.

Also, add a script to do this, since doing it manually with fmt sucks.

Conflicts:
	src/or/main.c

That is, GETINFO limits/max-mem-in-queues

If we can't detect the physical memory, the new default is 8 GB on
64-bit architectures, and 1 GB on 32-bit architectures.

If we *can* detect the physical memory, the new default is
  CLAMP(256 MB, phys_mem * 0.75, MAX_DFLT)
where MAX_DFLT is 8 GB on 64-bit architectures and 2 GB on 32-bit
architectures.

You can still override the default by hand.  The logic here is simply
trying to choose a lower default value on systems with less than 12 GB
of physical RAM.

Conflicts:
	src/or/circuitbuild.c

Use a per-channel ratelim_t to control the rate at which we report
failures for each channel.

Explain why I picked N=32.

Never return a zero circID.

Thanks to Andrea and to cypherpunks.

George Kadianakis authored 10 years ago and Nick Mathewson committed 10 years ago

Make it clear that a SIGHUP is not the only action that can cause a
config re-read.

George Kadianakis authored 10 years ago and Nick Mathewson committed 10 years ago

Since we need to toggle that element in non-SIGHUP situations too where
the config was re-read (like in SETCONF or RESETCONF).

George Kadianakis authored 10 years ago and Nick Mathewson committed 10 years ago

Instead, figure out if we should restart PT proxies _immediately_ after
we re-read the config file.

This is an "ours" merge, to avoid taking the 0.2.4 version of the

Conflicts:
	src/or/entrynodes.c

The memarea_strndup() function would have hit undefined behavior by
creating an 'end' pointer off the end of a string if it had ever been
given an 'n' argument bigger than the length of the memory ares that
it's scanning.  Fortunately, we never did that except in the unit
tests.  But it's not a safe behavior to leave lying around.

If we had an address of the form "1.2.3.4" and we tried to pass it to
tor_inet_pton with AF_INET6, it was possible for our 'eow' pointer to
briefly move backwards to the point before the start of the string,
before we moved it right back to the start of the string.  C doesn't
allow that, and though we haven't yet hit a compiler that decided to
nuke us in response, it's best to fix.

So, be more explicit about requiring there to be a : before any IPv4
address part of the IPv6 address.  We would have rejected addresses
without a : for not being IPv6 later on anyway.

Instead of taking the length of a buffer, we were taking the length of
a pointer, so that our debugging log would cover only the first
sizeof(void*) bytes of the client nonce.

We meant to using random bytes to fill a buffer, up to 3000 at a
time. Instead we were taking them sizeof(void*) at a time.

This is harmless, since tor-gencert exits right afterwards, but it's
best to clean up after ourselves.

scan-build didn't like the unlimited version since we might need to
overflow size_t to hexify a string that took up half our address
space. (!)

scan-build recognizes that in theory there could be a numeric overflow
here.

This can't numeric overflow can't trigger IRL, since in order to fill a
hash table with more than P=402653189 buckets with a reasonable load
factor of 0.5, we'd first have P/2 malloced objects to put in it--- and
each of those would have to take take at least sizeof(void*) worth of
malloc overhead plus sizeof(void*) content, which would run you out of
address space anyway on a 32-bit system.

If 'intro' is NULL in these functions, I'm pretty sure that the
error message must be set before we hit the end.  But scan-build
doesn't notice that, and is worried that we'll do a null-pointer
dereference in the last-chance errormsg generation.

As it stands, it relies on the fact that onion_queue_entry_remove
will magically remove each onionskin from the right list.  This
patch changes the logic to be more resilient to possible bugs in
onion_queue_entry_remove, and less confusing to static analysis tools.

scan-build doesn't realize that a request can't be timed at the end
unless it's timed at the start, and so it's not possible for us to
be subtracting start from end without start being set.
Nevertheless, let's not confuse it.

When get_proxy_addrport returned PROXY_NONE, it would leave
addr/port unset. This is inconsistent, and could (if we used the
function in a stupid way) lead to undefined behavior. Bugfix on
5b050a9b, though I don't think it affects tor-as-it-is.

Throughout circuituse, when we log about a circuit, we log its
desired path length from build_state. scan-build is irrationally
concerned that build_state might be NULL.

In circuitmux_detach_all_circuits, we check whether an HT iterator
gives us NULL.  That should be impossible for an HT iterator.  But
our checking it has confused scan-build (justly) into thinking that
our later use of HT_NEXT_RMV might not be kosher.  I'm taking the
coward's route here and strengthening the check.  Bugfix on
fd31dd44. (Not a real bug though)