Linux now supports Virtual Routing and Forwarding (VRF) as per:
https://www.kernel.org/doc/Documentation/networking/vrf.txt
In order for an application to bind or connect to a socket with an
address in a VRF, they need to first bind the socket to the VRF device:
setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, dev, strlen(dev)+1);
Note "dev" is the VRF device, eg. VRF "blue", rather than an interface
enslaved to the VRF.
Add a new socket option, ZMQ_BINDTODEVICE, to bind a socket to a device.
In general, if a socket is bound to a device, eg. an interface, only
packets received from that particular device are processed by the socket.
If device is a VRF device, then subsequent binds/connects to that socket
use addresses in the VRF routing table.
Solution:
* Document the new behaviour when generating 'ZMQ_POLLOUT' events
for ZMQ_ROUTER sockets with 'ZMQ_ROUTER_MANDATORY' set to `1`
* Add clarifications for 'ZMQ_ROUTER' socket when
'ZMQ_ROUTER_MANDATORY' is set to `1`
Problem: GSSAPI NAMETYPE options were not documented in man
pages for zmq_getsockopt() and zmq_setsockopt().
Solution: add new options to these manual pages.
Problem: the ZMQ_GSSAPI_PRINCIPAL socket option is described
as mandatory in the zmq_gssapi(7) manual page. In fact it
is optional.
Solution: Describe ZMQ_GSSAPI_PRINCIPAL as optional.
If unspecified, default credentials are used.
Solution: add a note pointing out that when new events are added the
ZMQ_EVENT_ALL mask will start returning them, so applications that
can't handle that transparently should not use it and instead pick
only the event types they want.
Creating a new event type and having monitors with ZMQ_EVENT_ALL
return them will not be considered a backward incompatible change
even though the flow of events will change.
Solution: fix it.
The documentation first states that the ZMQ_SNDMORE flag is ignored on
data frames. Then it states that omitting the ZMQ_SNDMORE flag has
consequences. The example HTTP server code further muddies the situation
with a similar comment.
The implementation of ZMQ_STREAM only accepts two-part messages.
The first part is an identity frame while the second and last part is
the data frame.
As with any multipart message, all parts except the last need the
ZMQ_SNDMORE flag. The second and last part would normally omit the
ZMQ_SNDMORE flag to mark the end of the multipart message.
However, the ZMQ_STREAM implementation ignores the ZMQ_SNDMORE flag on
the data frame rather than requiring that it be omitted. The latter
behaviour would have been more consistent with the other ZeroMQ
sockets.
Solution:
- Update formatting and remove redundant parts from ZMQ_PROBE_ROUTER,
ZMQ_USE_FD, ZMQ_TCP_MAXRT, ZMQ_TCP_TOS
- Only cosmetic changes to the content
- These changes already merged on api.zeromq.org by me
Problem: when using ZMQ_REQ_RELAXED + ZMQ_REQ_CORRELATE and two 'send' are
executed in a row and no server is available at the time of the sends,
then the internal request_id used to identify messages gets corrupted and
the two messages end up with the same request_id. The correlation no
longer works in that case and you may end up with the wrong message.
Solution: make a copy of the request_id instance member before sending it
down the pipe.
Solution: add the document files to the MAN_DOC and MAN_HTML targets
in doc/Makefile.am only if BUILD_DOC and INSTALL_MAN are set,
otherwise leave the targets empty to avoid errors in make distcheck.
And I'm on a reasonably sized laptop. I think allocating INT_MAX
memory is dangerous in a test case.
Solution: expose this as a context option. I've used ZMQ_MAX_MSGSZ
and documented it and implemented the API. However I don't know how
to get the parent context for a socket, so the code in zmq.cpp is
still unfinished.
These options are confusing and redundant. Their names suggest
they apply to the tcp:// transport, yet they are used for all
stream protocols. The methods zmq::set_tcp_receive_buffer and
zmq::set_tcp_send_buffer don't use these values at all, they use
ZMQ_SNDBUF and ZMQ_RCVBUF.
Solution: merge these new options into ZMQ_SNDBUF and ZMQ_RCVBUF.
This means defaulting these two options to 8192, and removing the
new options. We now have ZMQ_SNDBUF and ZMQ_RCVBUF being used both
for TCP socket control, and for input/output buffering.
Note: the default for SNDBUF and RCVBUF are otherwise 4096.
This option has a few issues. The name is long and clumsy. The
functonality is not smooth: one must set both this and
ZMQ_XPUB_VERBOSE at the same time, or things will break mysteriously.
Solution: rename to ZMQ_XPUB_VERBOSER and make an atomic option.
That is, implicitly does ZMQ_XPUB_VERBOSE.
Solution: be more explicit in the code, and in the zmq_recv man
page (which is the most unobvious case). Assert if length is not
zero and buffer is nonetheless null.
Solution: add new [set|get]sockopt ZMQ_PRE_ALLOCATED_FD to allow
users to let ZMQ use a pre-allocated file descriptor instead of
allocating a new one. Update [set|get]sockopt documentation and
test accordingly.
The main use case for this feature is a socket-activated systemd
service. For more information about this feature see:
http://0pointer.de/blog/projects/socket-activation.html
These sockets don't handle multipart data, so if callers send it,
they drop frames, and things break silently.
Solution: if the caller tries to use ZMQ_SNDMORE, return -1 and
set errno to EINVAL.
VMCI transport allows fast communication between the Host
and a virtual machine, between virtual machines on the same host,
and within a virtual machine (like IPC).
It requires VMware to be installed on the host and Guest Additions
to be installed on a guest.
