Add some clarifications to the async documentation. Also changed
ASYNC_pause_job() so that it returns success if you are not within the
context of a job. This is so that engines can be used either asynchronously
or synchronously and can treat an error from ASYNC_pause_job() as a real
error.

Reviewed-by: Rich Salz <rsalz@openssl.org>

Tidy up the libssl async calls and make sure all IO functions are covered.

Reviewed-by: Rich Salz <rsalz@openssl.org>

Reviewed-by: Rich Salz <rsalz@openssl.org>

Add ASYNCerr support to give some meaningful error message in the event of
a failure.

Reviewed-by: Rich Salz <rsalz@openssl.org>

Add a CHANGES entry for the new async code.

Reviewed-by: Rich Salz <rsalz@openssl.org>

s_server already had the ability to wait on an async file descriptor. This
adds it to s_client too.

Reviewed-by: Rich Salz <rsalz@openssl.org>

0 is a valid file descriptor so SSL_get_async_wait_fd should instead return
-1 on error.

Reviewed-by: Rich Salz <rsalz@openssl.org>

Document the libssl and command line application aspects of async.

Reviewed-by: Rich Salz <rsalz@openssl.org>

Tidied up the naming of functions and structures to be consistent

Reviewed-by: Rich Salz <rsalz@openssl.org>

Fix some warnings in the async code when compiling on windows.

Reviewed-by: Rich Salz <rsalz@openssl.org>

Don't recreate a new ASYNC_CTX every time we call ASYNC_start_job() - the
same one can be used for the life of the thread. Instead we only free it
up when we call ASYNC_free_pool().

Reviewed-by: Rich Salz <rsalz@openssl.org>

The ASYNC null implementation has not kept pace with the rest of the async
development and so was failing to compile.

Reviewed-by: Rich Salz <rsalz@openssl.org>

Add a suite of tests for the ASYNC_* functions

Reviewed-by: Rich Salz <rsalz@openssl.org>

The ASYNC_in_job() function is redundant. The same effect can be achieved by
using ASYNC_get_current_job().

Reviewed-by: Rich Salz <rsalz@openssl.org>

Reviewed-by: Rich Salz <rsalz@openssl.org>

Reviewed-by: Rich Salz <rsalz@openssl.org>

Port the async pool and notify code to windows.

Reviewed-by: Rich Salz <rsalz@openssl.org>

s_client was not freeing up the async pool if async mode was enabled.

Reviewed-by: Rich Salz <rsalz@openssl.org>

If an async event occurs during a renegotiation in SSL_read then s_server
was looping around, detecting we were in init and calling
init_ssl_connection instead of re-calling SSL_read.

Reviewed-by: Rich Salz <rsalz@openssl.org>

Implement the ASYNC_JOB as a local thread pool. Remove the API support
for global pools.

Reviewed-by: Rich Salz <rsalz@openssl.org>

Initial API implemented for notifying applications that an ASYNC_JOB
has completed. Currently only s_server is using this. The Dummy Async
engine "cheats" in that it notifies that it has completed *before* it
pauses the job. A normal async engine would not do that.

Only the posix version of this has been implemented so far, so it will
probably fail to compile on Windows at the moment.

Reviewed-by: Rich Salz <rsalz@openssl.org>

It is expensive to create the ASYNC_JOB objects due to the "makecontext"
call. This change adds support for pools of ASYNC_JOB objects so that we
don't have to create a new ASYNC_JOB every time we want to use one.

Reviewed-by: Rich Salz <rsalz@openssl.org>

Where we can we should use longjmp and setjmp in preference to swapcontext/
setcontext as they seem to be more performant.

Reviewed-by: Rich Salz <rsalz@openssl.org>

The s_server option -WWW was not async aware, and therefore was not
handling SSL_ERROR_WANT_ASYNC conditions. This commit fixes that.

Reviewed-by: Rich Salz <rsalz@openssl.org>

Removed the function ASYNC_job_is_waiting() as it was redundant. The only
time user code has a handle on a job is when one is waiting, so all they
need to do is check whether the job is NULL. Also did some cleanups to
make sure the job really is NULL after it has been freed!

Reviewed-by: Rich Salz <rsalz@openssl.org>

Some assembler code puts a lot of stuff on the stack, so up the stack size.

Reviewed-by: Rich Salz <rsalz@openssl.org>

Create a "null" async implementation for platforms that lack support. This
just does nothing when called and therefore performs synchronously.

Reviewed-by: Rich Salz <rsalz@openssl.org>

Reviewed-by: Rich Salz <rsalz@openssl.org>

Reviewed-by: Rich Salz <rsalz@openssl.org>

A new -async option is added which activates SSL_MODE_ASYNC. Also
SSL_WANT_ASYNC errors are handled appropriately.

Reviewed-by: Rich Salz <rsalz@openssl.org>

The following entry points have been made async aware:
SSL_accept
SSL_read
SSL_write

Also added is a new mode - SSL_MODE_ASYNC. Calling the above functions with
the async mode enabled will initiate a new async job. If an async pause is
encountered whilst executing the job (such as for example if using SHA1/RSA
with the Dummy Async engine), then the above functions return with
SSL_WANT_ASYNC. Calling the functions again (with exactly the same args
as per non-blocking IO), will resume the job where it left off.

Reviewed-by: Rich Salz <rsalz@openssl.org>

This engine is for developers of async aware applications. It simulates
asynchronous activity with external hardware. This initial version supports
SHA1 and RSA. Certain operations using those algorithms have async job
"pauses" in them - using the new libcrypto async capability.

Reviewed-by: Rich Salz <rsalz@openssl.org>

Provides support for running asynchronous jobs. Currently this is completely
stand alone. Future commits will integrate this into libssl and s_server/
s_client. An asynchronous capable engine will be required to see any benefit
from this capability.

Reviewed-by: Rich Salz <rsalz@openssl.org>

The forthcoming async code needs to use pthread thread local variables. This
updates the various Configurations to add the necessary flags. In many cases
this is an educated guess as I don't have access to most of these
environments! There is likely to be some tweaking needed.

Reviewed-by: Kurt Roeckx <kurt@openssl.org>

The al variable could be uninitialised in an error path.

Reviewed-by: Rich Salz <rsalz@openssl.org>

Reviewed-by: Rich Salz <rsalz@akamai.com>

RT #4100, MR #1264

Signed-off-by: Kurt Roeckx <kurt@roeckx.be>
Reviewed-by: Rich Salz <rsalz@akamai.com>

RT #4100, MR #1264

Reviewed-by: Matt Caswell <matt@openssl.org>

There are lots of calls to EVP functions from within libssl There were
various places where we should probably check the return value but don't.
This adds these checks.

Reviewed-by: Richard Levitte <levitte@openssl.org>

Use SHA256 for TSA and setted permitted digests to a sensible value.

Based on PR#4141

Reviewed-by: Matt Caswell <matt@openssl.org>