SSL standard library module wire-in

A patch implementation is provided, which augments and alters the Python
standard library's ssl module to support passing of datagram sockets, in which
case this package's DTLS protocol support will be activated. The ssl module's
interface is intended to operate identically regardless of whether the DTLS
protocol or another protocol is chosen.

The following features of the ssl module are explicitly supported with
datagram sockets:

    * socket wrapping, unwrapping, and re-wrapping
    * threaded UDP servers
    * asynchronous UDP servers (asyncore integration)
    * socket servers (SocketServer integration)

The following modules have been added:

    * dtls.patch: standard library module patching code and substitution
                  functions and methods
    * unit.py:    this is a port of the standard library's testing module
                  test_ssl.py for datagram sockets; all tests pass at this time;
                  a couple of inapplicable tests have been dropped; a few other
                  tests have been added

Also note that the err module's exception raising mechanism has been
augmented so as to raise exceptions of type ssl.SSLError (as opposed to
dtls.err.SSLError) when instructed to do so through activation of the patching
mechanism. This allows code written against the standard library module's
interface to remain unchanged. In some cases, types derived from
ssl.SSLError are raised.

dtls/test/certs/badcert.pem

@@ -0,0 +1,36 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIICXwIBAAKBgQC8ddrhm+LutBvjYcQlnH21PPIseJ1JVG2HMmN2CmZk2YukO+9L
+opdJhTvbGfEj0DQs1IE8M+kTUyOmuKfVrFMKwtVeCJphrAnhoz7TYOuLBSqt7lVH
+fhi/VwovESJlaBOp+WMnfhcduPEYHYx/6cnVapIkZnLt30zu2um+DzA9jQIDAQAB
+AoGBAK0FZpaKj6WnJZN0RqhhK+ggtBWwBnc0U/ozgKz2j1s3fsShYeiGtW6CK5nU
+D1dZ5wzhbGThI7LiOXDvRucc9n7vUgi0alqPQ/PFodPxAN/eEYkmXQ7W2k7zwsDA
+IUK0KUhktQbLu8qF/m8qM86ba9y9/9YkXuQbZ3COl5ahTZrhAkEA301P08RKv3KM
+oXnGU2UHTuJ1MAD2hOrPxjD4/wxA/39EWG9bZczbJyggB4RHu0I3NOSFjAm3HQm0
+ANOu5QK9owJBANgOeLfNNcF4pp+UikRFqxk5hULqRAWzVxVrWe85FlPm0VVmHbb/
+loif7mqjU8o1jTd/LM7RD9f2usZyE2psaw8CQQCNLhkpX3KO5kKJmS9N7JMZSc4j
+oog58yeYO8BBqKKzpug0LXuQultYv2K4veaIO04iL9VLe5z9S/Q1jaCHBBuXAkEA
+z8gjGoi1AOp6PBBLZNsncCvcV/0aC+1se4HxTNo2+duKSDnbq+ljqOM+E7odU+Nq
+ewvIWOG//e8fssd0mq3HywJBAJ8l/c8GVmrpFTx8r/nZ2Pyyjt3dH1widooDXYSV
+q6Gbf41Llo5sYAtmxdndTLASuHKecacTgZVhy0FryZpLKrU=
+-----END RSA PRIVATE KEY-----
+-----BEGIN CERTIFICATE-----
+Just bad cert data
+-----END CERTIFICATE-----
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
+-----BEGIN CERTIFICATE-----
+Just bad cert data
+-----END CERTIFICATE-----

dtls/test/certs/badkey.pem

@@ -0,0 +1,40 @@
+-----BEGIN RSA PRIVATE KEY-----
+Bad Key, though the cert should be OK
+-----END RSA PRIVATE KEY-----
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+-----BEGIN RSA PRIVATE KEY-----
+Bad Key, though the cert should be OK
+-----END RSA PRIVATE KEY-----
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

dtls/test/certs/keycert.pem

@@ -0,0 +1,21 @@
+-----BEGIN PRIVATE KEY-----
+MIIBVAIBADANBgkqhkiG9w0BAQEFAASCAT4wggE6AgEAAkEAuPd3JmydJfXhyii0
+agsVgRMOUcOyuldbaf/Lu4bZ+U0zH0OSoYkv0Ahbz7ehK+oGMeUy/SuGVAn7JLyj
+zlYi8QIDAQABAkAygtnV82lC2Y/Mbis+nkJEGlkZuRCQ1JRRMRqI3n2eF6CviqF3
+PiBXIEEExzKihC9bvbHKTAkYDLr+/4YpbiQBAiEA7JLS5Lp7KI/ayWwEzl2r5XXu
+k/cbH++A4zZz6A9XIsECIQDIJ8ciDa5/VGyQnYMzBNgKnwaFDDBOiEUFDaU/9ZN8
+MQIgCG3Gw819G9ncQrbtiOi/eiJ0iKMSPVYMMow7HvaE9UECIQCLyQwPwlJd5s4z
+aW4ZkYZ4VHuvK8YI8q6RSuhf9Nhd4QIgFbRNdEeehgrzGzGug2yVCMzVzS3MQNBJ
+6LqBZaPlFsM=
+-----END PRIVATE KEY-----
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

dtls/test/certs/wrongcert.pem

@@ -0,0 +1,32 @@
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

dtls/test/echo_seq.py

@@ -45,7 +45,7 @@ def main():
             break
 
     print "Accepting..."
-    conn = scn.accept()
+    conn = scn.accept()[0]
     sck.settimeout(5)
     conn.get_socket(True).settimeout(5)
 
@@ -59,7 +59,7 @@ def main():
         try:
             conn.do_handshake()
         except SSLError as err:
-            if err.args[0] == SSL_ERROR_WANT_READ:
+            if len(err.args) > 1 and err.args[1].args[0] == SSL_ERROR_WANT_READ:
                 continue
             raise
         print "Completed handshaking with peer"