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>

On win64 the size of file descriptor is not the same as size of int.
The bug in PGM transport caused a runtime error because of this.
The problem is fixed now.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

Removal of ZMQ_IDENTITY resulted in various session classes doing
almost the same thing. This patch merges the classes into a single
class.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

As PGM is not capable of passing subscriptions upstream,
subscriptions are ignored at sub side and engine subscribes
for all messages on pub side.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

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

There was an error in pgm_receiver wrt strict aliasing.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

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

The new option allows user to guard against peers sending
oversized messages. Connection to peer sending oversized message
is dropped.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

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

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

Otherwise the timer event can raise an input event
causing assertion on unprocessed data.
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>

Signed-off-by: Steven McCoy <steven.mccoy@miru.hk>

 * Assertion to check that pgm_getaddrinfo is actually returning something.
 * Missing pgm_connect call.
 * Typo on TOS causing immediate abort.
 * Placeholder calls for timeouts whilst continuing spin loop functionality.
 * OpenPGM v5 now supports reference counting so remove init checks.
 * Duplicate UDP unicast port setting, requires one unicast and one multicast.
 * Incorrectly set socket rcvbuf size with sndbuf.
 * Replace std::lexicographical_compare of TSI's with long word integer comparisons.
 * pgm_socket_t::receive returns -1 on no data.

This commit introduces the necessary changes necessary
for implementing flow control. None of the socket types
implements the flow control yet. The code will crash when
the flow control is enabled and the thw lwm is reached.

The following commits will add flow-control support for
individual socket types.

zmq_encoder/decoder are able to add/trim prefixes from messages; fair queueing and load balancing algorithms factorised into separate classes