tor/src/ext

OpenBSD_malloc_Linux.c:

The OpenBSD malloc implementation, ported to Linux. Used only when
--enable-openbsd-malloc is passed to the configure script.

strlcat.c
strlcpy.c

Implementations of strlcat and strlcpy, the more sane replacements
for strcat and strcpy. These are nonstandard, and some libc
implementations refuse to add them for religious reasons.

eventdns.[ch]

A fork of Libevent's DNS implementation, used by Tor when Libevent
2.0 or later is not available. Once Libevent 2.0 is required, we
should throw this away; it has diverged from evdns.[ch], and is
no longer easily mergeable.

ht.h

An implementation of a hash table in the style of Niels Provos's
tree.h. Shared with Libevent.

tinytest.[ch]
tinytest_demos.c
tinytest_macros.h

A unit testing framework. https://github.com/nmathewson/tinytest

tor_queue.h

A copy of sys/queue.h from OpenBSD. We keep our own copy rather
than using sys/queue.h, since some platforms don't have a
sys/queue.h, and the ones that do have diverged in incompatible
ways. (CIRCLEQ or no CIRCLEQ? SIMPLQ or STAILQ?) We also rename
the identifiers with a TOR_ prefix to avoid conflicts with
the system headers.

curve25519_donna/*.c

A copy of Adam Langley's curve25519-donna mostly-portable
implementations of curve25519.

csiphash.c
siphash.h

Marek Majkowski's implementation of siphash 2-4, a secure keyed
hash algorithm to avoid collision-based DoS attacks against hash
tables.