fixes #143 Protocols and transports should be "configurable"

This makes all the protocols and transports optional.  All
of them except ZeroTier are enabled by default, but you can
now disable them (remove from the build) with cmake options.

The test suite is modified so that tests still run as much
as they can, but skip over things caused by missing functionality
from the library (due to configuration).

Further, the constant definitions and prototypes for functions
that are specific to transports or protocols are moved into
appropriate headers, which should be included directly by
applications wishing to use these.

We have also added and improved documentation -- all of the
transports are documented, and several more man pages for
protocols have been added.  (Req/Rep and Surveyor are still
missing.)

3 files changed, 452 insertions, 0 deletions

diff --git a/src/protocol/bus0/CMakeLists.txt b/src/protocol/bus0/CMakeLists.txt
new file mode 100644
index 00000000..5071054a
--- /dev/null
+++ b/src/protocol/bus0/CMakeLists.txt
@@ -0,0 +1,18 @@
+#
+# Copyright 2017 Garrett D'Amore <garrett@damore.org>
+# Copyright 2017 Capitar IT Group BV <info@capitar.com>
+#
+# 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.
+#
+
+#  Bus protocol
+
+if (NNG_PROTO_BUS0)
+    set(BUS0_SOURCES protocol/bus0/bus.c protocol/bus0/bus.h)
+    install(FILES bus.h DESTINATION include/nng/protocol/bus0)
+endif()
+
+set(NNG_SOURCES ${NNG_SOURCES} ${BUS0_SOURCES} PARENT_SCOPE)
diff --git a/src/protocol/bus0/bus.c b/src/protocol/bus0/bus.c
new file mode 100644
index 00000000..3e15000b
--- /dev/null
+++ b/src/protocol/bus0/bus.c
@@ -0,0 +1,406 @@
+//
+// Copyright 2017 Garrett D'Amore <garrett@damore.org>
+// Copyright 2017 Capitar IT Group BV <info@capitar.com>
+//
+// 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.
+//
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "core/nng_impl.h"
+#include "protocol/bus0/bus.h"
+
+// Bus protocol.  The BUS protocol, each peer sends a message to its peers.
+// However, bus protocols do not "forward" (absent a device).  So in order
+// for each participant to receive the message, each sender must be connected
+// to every other node in the network (full mesh).
+
+#ifndef NNI_PROTO_BUS_V0
+#define NNI_PROTO_BUS_V0 NNI_PROTO(7, 0)
+#endif
+
+typedef struct bus0_pipe bus0_pipe;
+typedef struct bus0_sock bus0_sock;
+
+static void bus0_sock_getq(bus0_sock *);
+static void bus0_sock_send(void *, nni_aio *);
+static void bus0_sock_recv(void *, nni_aio *);
+
+static void bus0_pipe_getq(bus0_pipe *);
+static void bus0_pipe_send(bus0_pipe *);
+static void bus0_pipe_recv(bus0_pipe *);
+
+static void bus0_sock_getq_cb(void *);
+static void bus0_pipe_getq_cb(void *);
+static void bus0_pipe_send_cb(void *);
+static void bus0_pipe_recv_cb(void *);
+static void bus0_pipe_putq_cb(void *);
+
+// bus0_sock is our per-socket protocol private structure.
+struct bus0_sock {
+	int       raw;
+	nni_aio * aio_getq;
+	nni_list  pipes;
+	nni_mtx   mtx;
+	nni_msgq *uwq;
+	nni_msgq *urq;
+};
+
+// bus0_pipe is our per-pipe protocol private structure.
+struct bus0_pipe {
+	nni_pipe *    npipe;
+	bus0_sock *   psock;
+	nni_msgq *    sendq;
+	nni_list_node node;
+	nni_aio *     aio_getq;
+	nni_aio *     aio_recv;
+	nni_aio *     aio_send;
+	nni_aio *     aio_putq;
+	nni_mtx       mtx;
+};
+
+static void
+bus0_sock_fini(void *arg)
+{
+	bus0_sock *s = arg;
+
+	nni_aio_stop(s->aio_getq);
+	nni_aio_fini(s->aio_getq);
+	nni_mtx_fini(&s->mtx);
+	NNI_FREE_STRUCT(s);
+}
+
+static int
+bus0_sock_init(void **sp, nni_sock *nsock)
+{
+	bus0_sock *s;
+	int        rv;
+
+	if ((s = NNI_ALLOC_STRUCT(s)) == NULL) {
+		return (NNG_ENOMEM);
+	}
+	NNI_LIST_INIT(&s->pipes, bus0_pipe, node);
+	nni_mtx_init(&s->mtx);
+	if ((rv = nni_aio_init(&s->aio_getq, bus0_sock_getq_cb, s)) != 0) {
+		bus0_sock_fini(s);
+		return (rv);
+	}
+	s->raw = 0;
+	s->uwq = nni_sock_sendq(nsock);
+	s->urq = nni_sock_recvq(nsock);
+
+	*sp = s;
+	return (0);
+}
+
+static void
+bus0_sock_open(void *arg)
+{
+	bus0_sock *s = arg;
+
+	bus0_sock_getq(s);
+}
+
+static void
+bus0_sock_close(void *arg)
+{
+	bus0_sock *s = arg;
+
+	nni_aio_cancel(s->aio_getq, NNG_ECLOSED);
+}
+
+static void
+bus0_pipe_fini(void *arg)
+{
+	bus0_pipe *p = arg;
+
+	nni_aio_fini(p->aio_getq);
+	nni_aio_fini(p->aio_send);
+	nni_aio_fini(p->aio_recv);
+	nni_aio_fini(p->aio_putq);
+	nni_msgq_fini(p->sendq);
+	nni_mtx_fini(&p->mtx);
+	NNI_FREE_STRUCT(p);
+}
+
+static int
+bus0_pipe_init(void **pp, nni_pipe *npipe, void *s)
+{
+	bus0_pipe *p;
+	int        rv;
+
+	if ((p = NNI_ALLOC_STRUCT(p)) == NULL) {
+		return (NNG_ENOMEM);
+	}
+	NNI_LIST_NODE_INIT(&p->node);
+	nni_mtx_init(&p->mtx);
+	if (((rv = nni_msgq_init(&p->sendq, 16)) != 0) ||
+	    ((rv = nni_aio_init(&p->aio_getq, bus0_pipe_getq_cb, p)) != 0) ||
+	    ((rv = nni_aio_init(&p->aio_send, bus0_pipe_send_cb, p)) != 0) ||
+	    ((rv = nni_aio_init(&p->aio_recv, bus0_pipe_recv_cb, p)) != 0) ||
+	    ((rv = nni_aio_init(&p->aio_putq, bus0_pipe_putq_cb, p)) != 0)) {
+		bus0_pipe_fini(p);
+		return (rv);
+	}
+
+	p->npipe = npipe;
+	p->psock = s;
+	*pp      = p;
+	return (0);
+}
+
+static int
+bus0_pipe_start(void *arg)
+{
+	bus0_pipe *p = arg;
+	bus0_sock *s = p->psock;
+
+	nni_mtx_lock(&s->mtx);
+	nni_list_append(&s->pipes, p);
+	nni_mtx_unlock(&s->mtx);
+
+	bus0_pipe_recv(p);
+	bus0_pipe_getq(p);
+
+	return (0);
+}
+
+static void
+bus0_pipe_stop(void *arg)
+{
+	bus0_pipe *p = arg;
+	bus0_sock *s = p->psock;
+
+	nni_msgq_close(p->sendq);
+
+	nni_aio_stop(p->aio_getq);
+	nni_aio_stop(p->aio_send);
+	nni_aio_stop(p->aio_recv);
+	nni_aio_stop(p->aio_putq);
+
+	nni_mtx_lock(&s->mtx);
+	if (nni_list_active(&s->pipes, p)) {
+		nni_list_remove(&s->pipes, p);
+	}
+	nni_mtx_unlock(&s->mtx);
+}
+
+static void
+bus0_pipe_getq_cb(void *arg)
+{
+	bus0_pipe *p = arg;
+
+	if (nni_aio_result(p->aio_getq) != 0) {
+		// closed?
+		nni_pipe_stop(p->npipe);
+		return;
+	}
+	nni_aio_set_msg(p->aio_send, nni_aio_get_msg(p->aio_getq));
+	nni_aio_set_msg(p->aio_getq, NULL);
+
+	nni_pipe_send(p->npipe, p->aio_send);
+}
+
+static void
+bus0_pipe_send_cb(void *arg)
+{
+	bus0_pipe *p = arg;
+
+	if (nni_aio_result(p->aio_send) != 0) {
+		// closed?
+		nni_msg_free(nni_aio_get_msg(p->aio_send));
+		nni_aio_set_msg(p->aio_send, NULL);
+		nni_pipe_stop(p->npipe);
+		return;
+	}
+
+	bus0_pipe_getq(p);
+}
+
+static void
+bus0_pipe_recv_cb(void *arg)
+{
+	bus0_pipe *p = arg;
+	bus0_sock *s = p->psock;
+	nni_msg *  msg;
+
+	if (nni_aio_result(p->aio_recv) != 0) {
+		nni_pipe_stop(p->npipe);
+		return;
+	}
+	msg = nni_aio_get_msg(p->aio_recv);
+
+	if (nni_msg_header_insert_u32(msg, nni_pipe_id(p->npipe)) != 0) {
+		// XXX: bump a nomemory stat
+		nni_msg_free(msg);
+		nni_aio_set_msg(p->aio_recv, NULL);
+		nni_pipe_stop(p->npipe);
+		return;
+	}
+
+	nni_aio_set_msg(p->aio_putq, msg);
+	nni_aio_set_msg(p->aio_recv, NULL);
+	nni_msgq_aio_put(s->urq, p->aio_putq);
+}
+
+static void
+bus0_pipe_putq_cb(void *arg)
+{
+	bus0_pipe *p = arg;
+
+	if (nni_aio_result(p->aio_putq) != 0) {
+		nni_msg_free(nni_aio_get_msg(p->aio_putq));
+		nni_aio_set_msg(p->aio_putq, NULL);
+		nni_pipe_stop(p->npipe);
+		return;
+	}
+
+	// Wait for another recv.
+	bus0_pipe_recv(p);
+}
+
+static void
+bus0_sock_getq_cb(void *arg)
+{
+	bus0_sock *s = arg;
+	bus0_pipe *p;
+	bus0_pipe *lastp;
+	nni_msg *  msg;
+	nni_msg *  dup;
+	uint32_t   sender;
+
+	if (nni_aio_result(s->aio_getq) != 0) {
+		return;
+	}
+
+	msg = nni_aio_get_msg(s->aio_getq);
+
+	// The header being present indicates that the message
+	// was received locally and we are rebroadcasting. (Device
+	// is doing this probably.)  In this case grab the pipe
+	// ID from the header, so we can exclude it.
+	if (nni_msg_header_len(msg) >= 4) {
+		sender = nni_msg_header_trim_u32(msg);
+	} else {
+		sender = 0;
+	}
+
+	nni_mtx_lock(&s->mtx);
+	lastp = nni_list_last(&s->pipes);
+	NNI_LIST_FOREACH (&s->pipes, p) {
+		if (nni_pipe_id(p->npipe) == sender) {
+			continue;
+		}
+		if (p != lastp) {
+			if (nni_msg_dup(&dup, msg) != 0) {
+				continue;
+			}
+		} else {
+			dup = msg;
+		}
+		if (nni_msgq_tryput(p->sendq, dup) != 0) {
+			nni_msg_free(dup);
+		}
+	}
+	nni_mtx_unlock(&s->mtx);
+
+	if (lastp == NULL) {
+		nni_msg_free(msg);
+	}
+
+	bus0_sock_getq(s);
+}
+
+static void
+bus0_sock_getq(bus0_sock *s)
+{
+	nni_msgq_aio_get(s->uwq, s->aio_getq);
+}
+
+static void
+bus0_pipe_getq(bus0_pipe *p)
+{
+	nni_msgq_aio_get(p->sendq, p->aio_getq);
+}
+
+static void
+bus0_pipe_recv(bus0_pipe *p)
+{
+	nni_pipe_recv(p->npipe, p->aio_recv);
+}
+
+static int
+bus0_sock_setopt_raw(void *arg, const void *buf, size_t sz)
+{
+	bus0_sock *s = arg;
+	return (nni_setopt_int(&s->raw, buf, sz, 0, 1));
+}
+
+static int
+bus0_sock_getopt_raw(void *arg, void *buf, size_t *szp)
+{
+	bus0_sock *s = arg;
+	return (nni_getopt_int(s->raw, buf, szp));
+}
+
+static void
+bus0_sock_send(void *arg, nni_aio *aio)
+{
+	bus0_sock *s = arg;
+
+	nni_msgq_aio_put(s->uwq, aio);
+}
+
+static void
+bus0_sock_recv(void *arg, nni_aio *aio)
+{
+	bus0_sock *s = arg;
+
+	nni_msgq_aio_get(s->urq, aio);
+}
+
+static nni_proto_pipe_ops bus0_pipe_ops = {
+	.pipe_init  = bus0_pipe_init,
+	.pipe_fini  = bus0_pipe_fini,
+	.pipe_start = bus0_pipe_start,
+	.pipe_stop  = bus0_pipe_stop,
+};
+
+static nni_proto_sock_option bus0_sock_options[] = {
+	{
+	    .pso_name   = NNG_OPT_RAW,
+	    .pso_getopt = bus0_sock_getopt_raw,
+	    .pso_setopt = bus0_sock_setopt_raw,
+	},
+	// terminate list
+	{ NULL, NULL, NULL },
+};
+
+static nni_proto_sock_ops bus0_sock_ops = {
+	.sock_init    = bus0_sock_init,
+	.sock_fini    = bus0_sock_fini,
+	.sock_open    = bus0_sock_open,
+	.sock_close   = bus0_sock_close,
+	.sock_send    = bus0_sock_send,
+	.sock_recv    = bus0_sock_recv,
+	.sock_options = bus0_sock_options,
+};
+
+static nni_proto bus0_proto = {
+	.proto_version  = NNI_PROTOCOL_VERSION,
+	.proto_self     = { NNI_PROTO_BUS_V0, "bus" },
+	.proto_peer     = { NNI_PROTO_BUS_V0, "bus" },
+	.proto_flags    = NNI_PROTO_FLAG_SNDRCV,
+	.proto_sock_ops = &bus0_sock_ops,
+	.proto_pipe_ops = &bus0_pipe_ops,
+};
+
+int
+nng_bus0_open(nng_socket *sidp)
+{
+	return (nni_proto_open(sidp, &bus0_proto));
+}
diff --git a/src/protocol/bus0/bus.h b/src/protocol/bus0/bus.h
new file mode 100644
index 00000000..0ef3d391
--- /dev/null
+++ b/src/protocol/bus0/bus.h
@@ -0,0 +1,28 @@
+//
+// Copyright 2017 Garrett D'Amore <garrett@damore.org>
+// Copyright 2017 Capitar IT Group BV <info@capitar.com>
+//
+// 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 NNG_PROTOCOL_BUS0_BUS_H
+#define NNG_PROTOCOL_BUS0_BUS_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+NNG_DECL int nng_bus0_open(nng_socket *);
+
+#ifndef nng_bus_open
+#define nng_bus_open nng_bus0_open
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // NNG_PROTOCOL_BUS0_BUS_H