When a ZMQ_STREAM socket connection is broken (intentionally, via `shutdown()`
or accidentally via client crash or network failure), there is no way for the
application to dertermine that it should drop per-connection data (such as
buffers).
This contribution makes sure the application receives a 0-length message to
notify it that the connection has been broken. This is symmetric with the
process of closing the connection from within the application (where the
application sends a 0-length message to tell ZeroMQ to close the connection).
Conflicts:
CMakeLists.txt
- This seems redundant; is there a use case for NOT providing
the IPC credentials to the ZAP authenticator?
- More, why is IPC authentication done via libzmq instead of ZAP?
Is it because we're missing the transport type on the ZAP request?
Another take on LIBZMQ-568 to allow filtering IPC connections, this time
using ZAP. This change is backward compatible. If the
ZMQ_ZAP_IPC_CREDS option is set, the user, group, and process IDs of the
peer process are appended to the address (separated by colons) of a ZAP
request; otherwise, nothing changes. See LIBZMQ-568 and zmq_setsockopt
documentation for more information.
Documentation examples for zmq_msg_get and zmq_msg_more functions have an
incorrect call to zmq_msg_close function - with 'zmq_msg_t' as a parameter
despite 'zmq_msg_t *' is required, so it is impossible to compile these
examples properly.
Also for zmq_msg_get example - declaration of zmq_msg_t variable is added
(like it is done in other examples).
* ZMQ_REQ_STRICT was negative option (default 1) which goes against
the standard, where defaults are zero. I renamed this to
ZMQ_REQ_RELAXED.
* ZMQ_REQ_REQUEST_IDS felt clumsy and describes the technical solution
rather than the problem/requirement. I changed to ZMQ_REQ_CORRELATE
which seems more explicit.
* Removed redundant Z85 code and include files from project
* Simplified use of headers in test cases (now they all just use testutil.hpp)
* Export zmq_z85_encode() and zmq_z85_decode() in API
* Added man pages for these two functions
On ZMQ_CURVE_xxxKEY fetches, would return 41 bytes into caller's 40-byte
buffer. Now these fetches only return 41 bytes if the caller explicitly
provides a 41-byte buffer (i.e. the option size is 41).
* This is passed to the ZAP handler in the 'domain' field
* If not set, or empty, then NULL security does not call the ZAP handler
* This resolves the phantom ZAP request syndrome seen with sockets where
security was never intended (e.g. in test cases)
* This means if you install a ZAP handler, it will not get any requests
for new connections until you take some explicit action, which can be
setting a username/password for PLAIN, a key for CURVE, or the domain
for NULL.
This allows making a new request on a REQ socket by sending a new
message. Without the option set, calling send() after the first message
is done will continue to return an EFSM error.
It's useful for when a REQ is not getting a response. Previously that
meant creating a new socket or switching to DEALER.
* Documentation:
The default behavior of REQ sockets is to rely on the ordering of messages
to match requests and responses and that is usually sufficient. When this option
is set to 1, the REQ socket will prefix outgoing messages with an extra frame
containing a request id. That means the full message is (request id, 0,
user frames...). The REQ socket will discard all incoming messages that don't
begin with these two frames.
* Behavior change: When a REQ socket gets an invalid reply, it used to
discard the message and return EAGAIN. REQ sockets still discard
invalid messages, but keep looking at the next one automatically
until a good one is found or there are no more messages.
* Add test_req_request_ids.
The use of binary for CURVE keys is painful; you cannot easily copy
these in e.g. email, or use them directly in source code. There are
various encoding possibilities. Base16 and Base64 are not optimal.
Ascii85 is not safe for source (it generates quotes and escapes).
So, I've designed a new Base85 encoding, Z85, which is safe to use
in code and elsewhere, and I've modified libzmq to use this where
it also uses binary keys (in get/setsockopt).
Very simply, if you use a 32-byte value, it's Base256 (binary),
and if you use a 40-byte value, it's Base85 (Z85).
I've put the Z85 codec into z85_codec.hpp, it's not elegant C++
but it is minimal and it works. Feel free to rewrap as a real class
if this annoys you.
