prevent segfault for unknown protocol in test app

Tweaks to ssl hostname verification

This patch updates the source code to not seg fault when an unknown
protocol is specified on the command line in the test app: paho_cs_sub

Previously the output would be:
```
./paho_cs_pub my/topic --host bad://test.mosquitto.org --port 8081
Using topic my/topic
Connecting
Segmentation fault (core dumped)
```

After this patch the output is:
```
./paho_cs_pub my/topic --host bad://test.mosquitto.org --port 8081
Using topic my/topic
Connecting
Failed to connect
```
Signed-off-by: Keith Holman <keith.holman@windriver.com>

Return SSL_FATAL, not SOCKET_ERROR so that connecting fails with a host we can't verify.
Also return an error for OpenSSL internal errors.
Free peername to avoid a memory leak.
Signed-off-by: Jasper Wallace <jasper@arcolaenergy.com>

fix memory out of bound access and stack overflow in UTF8_validate

Fix directory location mismatches

Fix typo in printf format string

Signed-off-by: Dominik Thalhammer <dominik@thalhammer.it>

This patch contains some fixes to work with the paho test suite.
Signed-off-by: Keith Holman <keith.holman@windriver.com>

This patch fixes various warnings produced during the build the most
common warning, is the truncation of "size_t" (usually unsigned long) to
(int).  This patch explicitly casts the result to "int" in these cases
to supress the warning.  Additionally, this patch includes a fix to an
internal library load function to take a "const char *" parameter
instead of a "char *" parameter.
Signed-off-by: Keith Holman <keith.holman@windriver.com>

This patch adds a simple sha1 test program to the compilation for
testing the algorithm.  The sha1 algorithm is used for the initial
WebSocket handshake.
Signed-off-by: Keith Holman <keith.holman@windriver.com>

This patch adds a simple base64 test program to the compilation for
testing the algorithm.  The base64 algorithm is used for the initial
WebSocket handshake.
Signed-off-by: Keith Holman <keith.holman@windriver.com>

closes: #166

This patch provides an initial implementation for websocket support for
paho. For the websocket specification see RFC 6455.  The purpose of this
patch is to allow connnecting to an MQTT broker listening on a websocket
port (typically 80 [HTTP] or 443 [HTTPS]) to be able to communicate with
a client using the paho library.  Using websockets to communicate increases
the packet overhead both sending and receiving as well as additional setup
and ping packets.  However, using websockets allows for communications on
standard HTTP/HTTPS ports which are generally already configured by
firewalls to allow outside communications.

To use websockets, prefix the connection URI with either: "ws://" or
"wss://" for either websockets or secure websockets, repectfully.
Signed-off-by: Keith Holman <keith.holman@windriver.com>

To help understand the various connecting states this patch introduces
defines with the various states.  This helps make the code a bit easier
to understand.
Signed-off-by: Keith Holman <keith.holman@windriver.com>

Signed-off-by: Otavio Rodolfo Piske <opiske@redhat.com>

Returns a human-redable error string.
Signed-off-by: David Wagner <david.wagner@easymile.com>

Secure environment variables are not available in PR builds

cf. https://docs.travis-ci.com/user/pull-requests/#Pull-Requests-and-Security-Restrictions

Therefore, only use them in official builds.
Signed-off-by: David Wagner <david.wagner@easymile.com>