- Created a new option ZMQ_ROUTER_RAW_SOCK
    - Added new raw_encoder and raw_decoder to receive and send messages in raw form to remote client
    - Added test case file tests/test_raw_sock.cpp

    o To create a raw router sock set the ZMQ_ROUTER_RAW_SOCK option
    o ZMQ_MSGMORE flag is ignored for non-id messages
    o To terminate a remote connection send id message followed by zero length data message

Fixes #415.

This patch, salvaged from a trainwreck accidental merge earlier, adds a
new sockopt, ZMQ_DELAY_ATTACH_ON_CONNECT which prevents a end point
being available to push messages to until it has fully connected, making
connect work more like bind. This also applies to reconnecting sockets,
which may cause message loss of in-queue messages, so it is sensible to
use this in conjunction with a low HWM and potentially an alternative
acknowledgement path.

Notes on most of the individual commits can be found the repository log.

Revert "After speaking with Ben Gray and the discussion on the mailing list, this is an attempt to create a sockopt to allow connecting pipes to not immediately be available for traffic. The problem is in a PUSH to many PULL situation, where there is a connect to a PULL which is not there. This connect will immediately create a pipe (unlike bind), and traffic will be load balanced to that pipe. This means if there is a persistently unavailable end point then the traffic will queue until HWM is hit, and older messages will be lost."

This reverts commit fe3fb419.

After speaking with Ben Gray and the discussion on the mailing list, this is an attempt to create a sockopt to allow connecting pipes to not immediately be available for traffic. The problem is in a PUSH to many PULL situation, where there is a connect to a PULL which is not there. This connect will immediately create a pipe (unlike bind), and traffic will be load balanced to that pipe. This means if there is a persistently unavailable end point then the traffic will queue until HWM is hit, and older messages will be lost.

This patch adds a sockopt ZMQ_DELAY_ATTACH_ON_CONNECT, which if set to 1 will attempt to preempt this behavior. It does this by extending the use of the session_base to include in the outbound as well as the inbound pipe, and only associates the pipe with the socket once it receives the connected callback via a process_attach message. This works, and a test has been added to show so, but may introduce unexpected complications. The shutdown logic in this class has become marginally more awkward because of this, requiring the session to serve as the sink for both pipes if shutdown occurs with a still-connecting pipe in place. It is also possible there could be issues around flushing the messages, but as I could not directly think how to create such an issue I have not written any code with regards to that.

The documentation has been updated to reflect the change, but please do check over the code and test and review.

Rename type zmq_monitor_fn -> zmq_monitor for a more natural callback definition API (zmq_monitor type, monitor.function callback)

Assign arbitrary number of filters that will be applied for each new TCP transport
connection on a listening socket.
If no filters applied, then TCP transport allows connections from any ip.
If at least one filter is applied then new connection source ip should be matched.
To clear all filters call zmq_setsockopt(socket, ZMQ_TCP_ACCEPT_FILTER, NULL, 0).
Filter is a null-terminated string with ipv6 or ipv4 CIDR.

For example:
localhost
127.0.0.1
mail.ru/24
::1
::1/128
3ffe:1::
3ffe:1::/56

Returns -1 if the filter couldn't be assigned(format error or ipv6 filter with ZMQ_IPV4ONLY set)

P.S.
The only thing that worries me is that I had to re-enable 'default assign by reference constructor/operator'
for 'tcp_address_t' (and for my inherited class tcp_address_mask_t) to store it in std::vector in 'options_t'...

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

* Implemented new ctx API (_new, _destroy, _get, _set)
* Removed 'typesafe' macros from zmq.h
* Added support for MAX_SOCKETS (was tied into change for #337)
* Created new man pages

However, the "durable socket" behaviour wasn't re-added.
Identities are used solely for routing in REQ/REP pattern.
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: Martin Sustrik <sustrik@250bpm.com>

At this point option exists, is documented and can be set,
however, it has no effect.
Signed-off-by: Steven McCoy <steven.mccoy@miru.hk>
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

This patch simplifies the whole codebase significantly,
including dropping depedency on libuuid.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

It was used only by ROUTER socket. After its removal it became
obsolete.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

The filtering is now done depending on the socket type. SUB socket
filters the messages (end-to-end filtering) while XSUB relies
on upstream nodes to do (imprefect) filtering.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

So far the requests in req/rep pattern were delivered to and processed
by worker even though the original requester was dead. Thus,
the worker processing replies with noone to deliver results to.
This optimisation drops requests in two situations:

1. Queued inbound requests in XREP socket when peer disconnects.
2. Queued outbound requests in XREQ when socket is closed.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

- Add doc and tests
- Add options and setup
- Wait using poll/select
Signed-off-by: Fabien Ninoles <fabien@tzone.org>
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

This option is a performance tweak. In devices XSUB socket filters
the messages just to send them to XPUB socket which filters them
once more. Setting ZMQ_FILTER option to 0 allows to switch the
filtering in XSUB socket off.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

So far, there was a pair of unidirectional pipes between a socket
and a session (or an inproc peer). This resulted in complex
problems with half-closed states and tracking which inpipe
corresponds to which outpipe.

This patch doesn't add any functionality in itself, but is
essential for further work on features like subscription
forwarding.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

Sets the time-to-live field in every multicast packet sent from the socket.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

These new options allow to control the maximum size of the
inbound and outbound message pipe separately.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

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

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

This mimics POSIX specification.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

There's only one option now -- ZMQ_RECOVRY_IVL --
and it's measured in milliseconds.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

On-disk storage should be implemented in devices rather than
in 0MQ core. 0MQ is a networking library and there's no point
in storing network buffers on disk.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

Multicast loopback is not a real multicast, rather a kernel-space
simulation. Moreover, it tends to be rather unreliable and lossy.
Removing the option will force users to use transports better
suited for the job, such as inproc or ipc.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

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