Move transport.[ch] to SP

1 files changed, 196 insertions, 0 deletions

diff --git a/src/sp/transport.h b/src/sp/transport.h
new file mode 100644
index 00000000..b2da2c7a
--- /dev/null
+++ b/src/sp/transport.h
@@ -0,0 +1,196 @@
+//
+// Copyright 2020 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2018 Capitar IT Group BV <info@capitar.com>
+// Copyright 2018 Devolutions <info@devolutions.net>
+//
+// This software is supplied under the terms of the MIT License, a
+// copy of which should be located in the distribution where this
+// file was obtained (LICENSE.txt).  A copy of the license may also be
+// found online at https://opensource.org/licenses/MIT.
+//
+
+#ifndef CORE_TRANSPORT_H
+#define CORE_TRANSPORT_H
+
+#include "core/options.h"
+
+// We quite intentionally use a signature where the upper word is nonzero,
+// which ensures that if we get garbage we will reject it.  This is more
+// likely to mismatch than all zero bytes would.  The actual version is
+// stored in the lower word; this is not semver -- the numbers are just
+// increasing - we doubt it will increase more than a handful of times
+// during the life of the project.  If we add a new version, please keep
+// the old version around -- it may be possible to automatically convert
+// older versions in the future.
+#define NNI_TRANSPORT_V0 0x54520000
+#define NNI_TRANSPORT_V1 0x54520001
+#define NNI_TRANSPORT_V2 0x54520002
+#define NNI_TRANSPORT_V3 0x54520003
+#define NNI_TRANSPORT_V4 0x54520004
+#define NNI_TRANSPORT_V5 0x54520005
+#define NNI_TRANSPORT_V6 0x54220006
+#define NNI_TRANSPORT_V7 0x54220006
+#define NNI_TRANSPORT_VERSION NNI_TRANSPORT_V7
+
+// Endpoint operations are called by the socket in a
+// protocol-independent fashion.  The socket makes individual calls,
+// which are expected to block if appropriate (except for destroy), or
+// run asynchronously if an aio is provided. Endpoints are unable to
+// call back into the socket, to prevent recusive entry and deadlock.
+//
+// For a given endpoint, the framework holds a lock so that each entry
+// point is run exclusively of the others. (Transports must still guard
+// against any asynchronous operations they manage themselves, though.)
+
+struct nni_tran_dialer_ops {
+	// d_init creates a vanilla dialer. The value created is
+	// used for the first argument for all other dialer functions.
+	int (*d_init)(void **, nni_url *, nni_dialer *);
+
+	// d_fini frees the resources associated with the dialer.
+	// The dialer will already have been closed.
+	void (*d_fini)(void *);
+
+	// d_connect establishes a connection.  It can return errors
+	// NNG_EACCESS, NNG_ECONNREFUSED, NNG_EBADADDR,
+	// NNG_ECONNFAILED, NNG_ETIMEDOUT, and NNG_EPROTO.
+	void (*d_connect)(void *, nni_aio *);
+
+	// d_close stops the dialer from operating altogether.  It
+	// does not affect pipes that have already been created.  It is
+	// nonblocking.
+	void (*d_close)(void *);
+
+	// d_getopt is used to obtain an option.
+	int (*d_getopt)(void *, const char *, void *, size_t *, nni_type);
+
+	// d_setopt is used to set or change an option.
+	int (*d_setopt)(void *, const char *, const void *, size_t, nni_type);
+
+	// d_options is an array of dialer options.  The final
+	// element must have a NULL name. If this member is NULL, then
+	// no dialer specific options are available.
+	nni_option *d_options;
+};
+
+struct nni_tran_listener_ops {
+	// l_init creates a vanilla listener. The value created is
+	// used for the first argument for all other listener functions.
+	int (*l_init)(void **, nni_url *, nni_listener *);
+
+	// l_fini frees the resources associated with the listener.
+	// The listener will already have been closed.
+	void (*l_fini)(void *);
+
+	// l_bind just does the bind() and listen() work,
+	// reserving the address but not creating any connections.
+	// It should return NNG_EADDRINUSE if the address is already
+	// taken.  It can also return NNG_EBADADDR for an unsuitable
+	// address, or NNG_EACCESS for permission problems.
+	int (*l_bind)(void *);
+
+	// l_accept accepts an inbound connection.
+	void (*l_accept)(void *, nni_aio *);
+
+	// l_close stops the listener from operating altogether.  It
+	// does not affect pipes that have already been created.  It is
+	// nonblocking.
+	void (*l_close)(void *);
+
+	// l_getopt is used to obtain an option.
+	int (*l_getopt)(void *, const char *, void *, size_t *, nni_type);
+
+	// l_setopt is used to set or change an option.
+	int (*l_setopt)(void *, const char *, const void *, size_t, nni_type);
+
+	// l_options is an array of listener options.  The final
+	// element must have a NULL name. If this member is NULL, then
+	// no dialer specific options are available.
+	nni_option *l_options;
+};
+
+// Pipe operations are entry points called by the socket. These may be
+// called with socket locks held, so it is forbidden for the transport
+// to call back into the socket at this point.  (Which is one reason
+// pointers back to socket or even enclosing pipe state, are not
+// provided.)
+struct nni_tran_pipe_ops {
+	// p_init initializes the pipe data structures.  The main
+	// purpose of this is so that the pipe will see the upper
+	// layer nni_pipe and get a chance to register stats and such.
+	int (*p_init)(void *, nni_pipe *);
+
+	// p_fini destroys the pipe.  This should clean up all local
+	// resources, including closing files and freeing memory, used
+	// by the pipe.  After this call returns, the system will not
+	// make further calls on the same pipe.
+	void (*p_fini)(void *);
+
+	// p_stop stops the pipe, waiting for any callbacks that are
+	// outstanding to complete.  This is done before tearing down
+	// resources with p_fini.
+	void (*p_stop)(void *);
+
+	// p_aio_send queues the message for transmit.  If this fails,
+	// then the caller may try again with the same message (or free
+	// it).  If the call succeeds, then the transport has taken
+	// ownership of the message, and the caller may not use it
+	// again.  The transport will have the responsibility to free
+	// the message (nng_msg_free()) when it is finished with it.
+	void (*p_send)(void *, nni_aio *);
+
+	// p_recv schedules a message receive. This will be performed
+	// even for cases where no data is expected, to allow detection
+	// of a remote disconnect.
+	void (*p_recv)(void *, nni_aio *);
+
+	// p_close closes the pipe.  Further recv or send operations
+	// should return back NNG_ECLOSED.
+	void (*p_close)(void *);
+
+	// p_peer returns the peer protocol. This may arrive in
+	// whatever transport specific manner is appropriate.
+	uint16_t (*p_peer)(void *);
+
+	// p_getopt is used to obtain an option.  Pipes don't implement
+	// option setting.
+	int (*p_getopt)(void *, const char *, void *, size_t *, nni_type);
+};
+
+// Transport implementation details.  Transports must implement the
+// interfaces in this file.
+struct nni_tran {
+	// tran_version is the version of the transport ops that this
+	// transport implements.  We only bother to version the main
+	// ops vector.
+	uint32_t tran_version;
+
+	// tran_scheme is the transport scheme, such as "tcp" or "inproc".
+	const char *tran_scheme;
+
+	// tran_dialer links our dialer-specific operations.
+	const nni_tran_dialer_ops *tran_dialer;
+
+	// tran_listener links our listener-specific operations.
+	const nni_tran_listener_ops *tran_listener;
+
+	// tran_pipe links our pipe-specific operations.
+	const nni_tran_pipe_ops *tran_pipe;
+
+	// tran_init, if not NULL, is called once during library
+	// initialization.
+	int (*tran_init)(void);
+
+	// tran_fini, if not NULL, is called during library deinitialization.
+	// It should release any global resources, close any open files, etc.
+	void (*tran_fini)(void);
+};
+
+// These APIs are used by the framework internally, and not for use by
+// transport implementations.
+extern nni_tran *nni_tran_find(nni_url *);
+extern int       nni_tran_sys_init(void);
+extern void      nni_tran_sys_fini(void);
+extern int       nni_tran_register(const nni_tran *);
+
+#endif // CORE_TRANSPORT_H