The existing code was largely set up for SN-to-SN or client-to-SN
communications, where messages can always get to the right place because
we can always send by pubkey.
This doesn't work when we want general communications with a random
remote address.
This commit overhauls the way loki-mq handles communication in a few
important ways:
- Listening instances no longer pass bind addresses into the
constructor; instead they call `listen_curve()` or `listen_plain()`
before invoking `start()`.
- `listen_curve()` is equivalent to the existing bind support: it
listens on a socket and accepts encrypted handshaked connections from
anyone who already knows the server's public key.
- `listen_plain()` is all new: it sets up a plain text listening socket
over which random clients can connect and talk. End-points aren't
verified, and it isn't encrypted, but if you don't know who you are
talking to then encryption isn't doing anything anyway.
- Connecting to a remote now connections in CURVE encryption or NULL
(plain-text) encryption based on whether you provide a remote_pubkey.
For CURVE, the connection will fail if the pubkey does not match.
- `ConnectionID` objects are now returned when connecting to a remote
address; this object is then passed in to send/request/etc. to direct
the message. For SN communication, ConnectionID's can be created
implicitly from SN pubkey strings, so the existing interface of
`lmq.send(pubkey, ...)` will still work in most cases.
- A ConnectionID is now passed to the ConnectSuccess and ConnectFailure
callbacks. This can be used to uniquely identify which connection
succeeded or failed, and can determine whether the remote is a service
node (`.sn()`) and/or the pubkey (`.pubkey()`). (Obviously the service
node status is only available when the client can do service node
lookups, and the pubkey() is only non-empty for encrypted connections).
string_view isn't supposed to be implicitly convertible to std::string
and code would break compiling under c++17 (when our local string_view
is simply a std::string_view typedef).
LMQ_TRACE becomes nothing under a release build, which is good because
many traces are in the proxy hot path.
Also fixes some confusing log level comparison logic by flipping the
order of log levels. Previous trace < debug < info < warn, which was
confusing: now that order is reversed which makes way more sense (i.e.
larger LogLevel means more logging).
Batch jobs scheduled by the proxy thread itself were delayed to the next
poll timeout (because nothing ever gets sent on a socket). Add a
variable to bypass the next poll to handle this case.
This allows making RPC requests with a callback that gets called when
the response comes back. The is essentially a wrapper around doing it
yourself (i.e. by setting up a server-side "request" and client-side
"reply" command where "request" responds with a "reply" command), but
abstracted into lokimq itself as it is likely to be very useful when
integrating client/server connections rather than peer-to-peer
connections.
This overhauls the proposed batch implementation (described in the
README but previously not implemented) and implements it.
Various other minor improvements and code restructuring.
Added a proposed "request" type to the README to be implemented; this is
like a command, but always expects a ["REPLY", TAG, ...] response. The
request invoker provides a callback to invoke when such a REPLY arrives.
This library is adapted from lokid's existing quorumnet code (added in
6.x) used for SN-to-SN communication for quorum voting but generalized
to be usable both there and as a basis for other communication channels
with loki projects (for example: wallet-to-lokid communication; loki-ss
and lokinet internal communication with lokid; loki-ss to loki-ss
communication and message passing; perhaps eventually loki p2p traffic).
This initial release compiles but likely has a few warts and bugs that
need ironing out in the implementation before it is production ready.
Some tests will follow.
Jason Rhinelander