The window scale option carried in SYN segment is computed from socket's
receive buffer size. So we need to set this buffer size before calling
connect or bind.

- we need to switch to PLAIN according to options.mechanism
- we need to catch case when both peers are as-server (or neither is)
- and to use username/password from options, for client

This implements protocol handshake.
We still need to design and implement 1) API changes so a user
can set username and password, and 2) a mechanism for engine
to authenticate users.

Copyrights had become ads for Sustrik's corporate sponsors, going against the original
agreement to share copyrights with the community (that agreement was: one line stating
iMatix copyright + one reference to AUTHORS file). The proliferation of corporate ads
is also unfair to the many individual authors. I've removed ALL corporate title from
the source files so the copyright statements can now be centralized in AUTHORS and
source files can be properly updated on an annual basis.

Copy monitor specific event endpoints to event messages as the engine etc. can be released at anytime

Significantly reworked the monitoring infrastructure with a more granular per socket API and to play well with monitoring endpoints in application threads

This also fixes a bug in tcp_connecter and tcp_listener, which
generated the event not when they failed to close the socket but
when the succeed to close it.

Calling close () when the underlying socket is invalid
triggers an assertion failure.

Make start_connecting () to have singe exit point.

The patch is meant to make the code easier to understand.
The 'wait' attribute is replaced by 'delayed_start'
and 'timer_started' attributes. The former is constant and
is initialized in the constructor. The latter is a flag
reflecting whether a timer has been started and changes during
the lifetime of the object.

This reverts commit 029d3dfa.

This reverts commit dde69fb9.

This reverts commit 33459029, reversing
changes made to 889b0e6f.

This reverts commit 7b105865, reversing
changes made to 33459029.

Once the object has been terminated, it is unsafe for this object
to refer to its parent.

The bug was responsible for occasional
test_shutdown_stress failures.

The TCP keepalive tuning code has been moved into the newly added
files; this also allows future TCP-specific code to be added into
these files, without bloating the IP level code and establishes a
known file structure for other IP-based transports.

Remember: this is a no-op change, hence no API or functionality
was changed as part of this commit.

Patch from Mato that fixes a subtle connect bug: EAGAIN was being used as a translation value for EINPROGRESS, thus
shadowing a real EAGAIN return value from the OS.  This caused later
assertions of "Invalid argument" in stream_engine.cpp when it attempted to
use a socket which was not connected.

I also add EINTR to mean EINPROGRESS, as per the POSIX and FreeBSD
documentation which specifies that a connect() call interrupted due to a
signal will complete asynchronously.
Signed-off-by: Martin Lucina <martin@lucina.net>

currently not fully cross-platform
work on linux
possibly work in *bsd
and could be enhanced to work on windows

This allows us to actually report an error to the caller on resolve
failure, rather than asserting later on in the io thread.
Signed-off-by: Staffan Gimåker <staffan@spotify.com>

Signed-off-by: Ivo Danihelka <ivo@danihelka.net>

failed: s == retired_fd (ipc_connecter.cpp:174), as reported in LIBZMQ-294.

This patch fixes the bug, and also an identical problem in tcp_connecter
which has not hit people since TCP connect() usually completes via the
asynchronous code path (poll, out_event).
Signed-off-by: Martin Lucina <martin@lucina.net>

A synchronous connect() failure in ipc_connecter can result in Assertion
failed: s == retired_fd (ipc_connecter.cpp:174), as reported in LIBZMQ-294.

This patch fixes the bug, and also an identical problem in tcp_connecter
which has not hit people since TCP connect() usually completes via the
asynchronous code path (poll, out_event).
Signed-off-by: Martin Lucina <martin@lucina.net>

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

This is a preliminary patch allowing for socket-type-specific
functionality in the I/O thread. For example, message format
can be checked asynchronously and misbehaved connections dropped
straight away.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

When exec is executed to start a different process image old
0MQ file descriptors could stay open, thus blocking TCP ports
and alike. This patch should solve the problem.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

The engine was not used exclusively for TCP connections.
Rather it was used to handle any socket with SOCK_STREAM
semantics. The class was renamed to reflect its true function.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

Signed-off-by: Steven McCoy <steven.mccoy@miru.hk>
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>