keepalive: switch from thread to threading module The thread module in py3 is renamed to _thread, but we can use the high level threading module instead.

py3: conditionalize httplib import The httplib library is renamed to http.client in python 3. So the import is conditionalized and a test is added in check-code to warn to use util.httplib

Added signature for changeset 26a5d605b868

Added tag 3.8.4 for changeset 26a5d605b868

sslutil: synchronize hostname matching logic with CPython sslutil contains its own hostname matching logic. CPython has code for the same intent. However, it is only available to Python 2.7.9+ (or distributions that have backported 2.7.9's ssl module improvements). This patch effectively imports CPython's hostname matching code from its ssl.py into sslutil.py. The hostname matching code itself is pretty similar. However, the DNS name matching code is much more robust and spec conformant. As the test changes show, this changes some behavior around wildcard handling and IDNA matching. The new behavior allows wildcards in the middle of words (e.g. 'f*.com' matches 'foo.com') This is spec compliant according to RFC 6125 Section 6.5.3 item 3. There is one test where the matcher is more strict. Before, '*.a.com' matched '.a.com'. Now it doesn't match. Strictly speaking this is a security vulnerability.

tests: import CPython's hostname matching tests CPython has a more comprehensive test suite for it's built-in hostname matching functionality. This patch adds its tests so we can improve our hostname matching functionality. Many of the tests have different results from CPython. These will be addressed in a subsequent commit.