fixes #1345 Restructure the source tree

This is not quite complete, but it sets the stage for other
protocols (such as zmq or mqtt) to be added to the project.

1 files changed, 705 insertions, 0 deletions

diff --git a/src/sp/protocol/reqrep0/rep.c b/src/sp/protocol/reqrep0/rep.c
new file mode 100644
index 00000000..aa32d249
--- /dev/null
+++ b/src/sp/protocol/reqrep0/rep.c
@@ -0,0 +1,705 @@
+//
+// Copyright 2020 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2018 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 <string.h>
+
+#include "core/nng_impl.h"
+#include "nng/protocol/reqrep0/rep.h"
+
+// Response protocol.  The REP protocol is the "reply" side of a
+// request-reply pair.  This is useful for building RPC servers, for
+// example.
+
+typedef struct rep0_pipe rep0_pipe;
+typedef struct rep0_sock rep0_sock;
+typedef struct rep0_ctx  rep0_ctx;
+
+static void rep0_pipe_send_cb(void *);
+static void rep0_pipe_recv_cb(void *);
+static void rep0_pipe_fini(void *);
+
+struct rep0_ctx {
+	rep0_sock *   sock;
+	uint32_t      pipe_id;
+	rep0_pipe *   spipe; // send pipe
+	nni_aio *     saio;  // send aio
+	nni_aio *     raio;  // recv aio
+	nni_list_node sqnode;
+	nni_list_node rqnode;
+	size_t        btrace_len;
+	uint32_t      btrace[NNI_MAX_MAX_TTL + 1];
+};
+
+// rep0_sock is our per-socket protocol private structure.
+struct rep0_sock {
+	nni_mtx        lk;
+	nni_atomic_int ttl;
+	nni_id_map     pipes;
+	nni_list       recvpipes; // list of pipes with data to receive
+	nni_list       recvq;
+	rep0_ctx       ctx;
+	nni_pollable   readable;
+	nni_pollable   writable;
+};
+
+// rep0_pipe is our per-pipe protocol private structure.
+struct rep0_pipe {
+	nni_pipe *    pipe;
+	rep0_sock *   rep;
+	uint32_t      id;
+	nni_aio       aio_send;
+	nni_aio       aio_recv;
+	nni_list_node rnode; // receivable list linkage
+	nni_list      sendq; // contexts waiting to send
+	bool          busy;
+	bool          closed;
+};
+
+static void
+rep0_ctx_close(void *arg)
+{
+	rep0_ctx * ctx = arg;
+	rep0_sock *s   = ctx->sock;
+	nni_aio *  aio;
+
+	nni_mtx_lock(&s->lk);
+	if ((aio = ctx->saio) != NULL) {
+		rep0_pipe *pipe = ctx->spipe;
+		ctx->saio       = NULL;
+		ctx->spipe      = NULL;
+		nni_list_remove(&pipe->sendq, ctx);
+		nni_aio_finish_error(aio, NNG_ECLOSED);
+	}
+	if ((aio = ctx->raio) != NULL) {
+		nni_list_remove(&s->recvq, ctx);
+		ctx->raio = NULL;
+		nni_aio_finish_error(aio, NNG_ECLOSED);
+	}
+	nni_mtx_unlock(&s->lk);
+}
+
+static void
+rep0_ctx_fini(void *arg)
+{
+	rep0_ctx *ctx = arg;
+
+	rep0_ctx_close(ctx);
+}
+
+static int
+rep0_ctx_init(void *carg, void *sarg)
+{
+	rep0_sock *s   = sarg;
+	rep0_ctx * ctx = carg;
+
+	NNI_LIST_NODE_INIT(&ctx->sqnode);
+	NNI_LIST_NODE_INIT(&ctx->rqnode);
+	ctx->btrace_len = 0;
+	ctx->sock       = s;
+	ctx->pipe_id    = 0;
+
+	return (0);
+}
+
+static void
+rep0_ctx_cancel_send(nni_aio *aio, void *arg, int rv)
+{
+	rep0_ctx * ctx = arg;
+	rep0_sock *s   = ctx->sock;
+
+	nni_mtx_lock(&s->lk);
+	if (ctx->saio != aio) {
+		nni_mtx_unlock(&s->lk);
+		return;
+	}
+	nni_list_node_remove(&ctx->sqnode);
+	ctx->saio = NULL;
+	nni_mtx_unlock(&s->lk);
+
+	nni_msg_header_clear(nni_aio_get_msg(aio)); // reset the headers
+	nni_aio_finish_error(aio, rv);
+}
+
+static void
+rep0_ctx_send(void *arg, nni_aio *aio)
+{
+	rep0_ctx * ctx = arg;
+	rep0_sock *s   = ctx->sock;
+	rep0_pipe *p;
+	nni_msg *  msg;
+	int        rv;
+	size_t     len;
+	uint32_t   p_id; // pipe id
+
+	msg = nni_aio_get_msg(aio);
+	nni_msg_header_clear(msg);
+
+	if (nni_aio_begin(aio) != 0) {
+		return;
+	}
+
+	nni_mtx_lock(&s->lk);
+	len  = ctx->btrace_len;
+	p_id = ctx->pipe_id;
+
+	// Assert "completion" of the previous req request.  This ensures
+	// exactly one send for one receive ordering.
+	ctx->btrace_len = 0;
+	ctx->pipe_id    = 0;
+
+	if (ctx == &s->ctx) {
+		// No matter how this goes, we will no longer be able
+		// to send on the socket (root context).  That's because
+		// we will have finished (successfully or otherwise) the
+		// reply for the single request we got.
+		nni_pollable_clear(&s->writable);
+	}
+	if (len == 0) {
+		nni_mtx_unlock(&s->lk);
+		nni_aio_finish_error(aio, NNG_ESTATE);
+		return;
+	}
+	if ((rv = nni_msg_header_append(msg, ctx->btrace, len)) != 0) {
+		nni_mtx_unlock(&s->lk);
+		nni_aio_finish_error(aio, rv);
+		return;
+	}
+	if ((p = nni_id_get(&s->pipes, p_id)) == NULL) {
+		// Pipe is gone.  Make this look like a good send to avoid
+		// disrupting the state machine.  We don't care if the peer
+		// lost interest in our reply.
+		nni_mtx_unlock(&s->lk);
+		nni_aio_set_msg(aio, NULL);
+		nni_aio_finish(aio, 0, nni_msg_len(msg));
+		nni_msg_free(msg);
+		return;
+	}
+	if (!p->busy) {
+		p->busy = true;
+		len     = nni_msg_len(msg);
+		nni_aio_set_msg(&p->aio_send, msg);
+		nni_pipe_send(p->pipe, &p->aio_send);
+		nni_mtx_unlock(&s->lk);
+
+		nni_aio_set_msg(aio, NULL);
+		nni_aio_finish(aio, 0, len);
+		return;
+	}
+
+	if ((rv = nni_aio_schedule(aio, rep0_ctx_cancel_send, ctx)) != 0) {
+		nni_mtx_unlock(&s->lk);
+		nni_aio_finish_error(aio, rv);
+		return;
+	}
+
+	ctx->saio  = aio;
+	ctx->spipe = p;
+	nni_list_append(&p->sendq, ctx);
+	nni_mtx_unlock(&s->lk);
+}
+
+static void
+rep0_sock_fini(void *arg)
+{
+	rep0_sock *s = arg;
+
+	nni_id_map_fini(&s->pipes);
+	rep0_ctx_fini(&s->ctx);
+	nni_pollable_fini(&s->writable);
+	nni_pollable_fini(&s->readable);
+	nni_mtx_fini(&s->lk);
+}
+
+static int
+rep0_sock_init(void *arg, nni_sock *sock)
+{
+	rep0_sock *s = arg;
+
+	NNI_ARG_UNUSED(sock);
+
+	nni_mtx_init(&s->lk);
+	nni_id_map_init(&s->pipes, 0, 0, false);
+	NNI_LIST_INIT(&s->recvq, rep0_ctx, rqnode);
+	NNI_LIST_INIT(&s->recvpipes, rep0_pipe, rnode);
+	nni_atomic_init(&s->ttl);
+	nni_atomic_set(&s->ttl, 8);
+
+	(void) rep0_ctx_init(&s->ctx, s);
+
+	// We start off without being either readable or writable.
+	// Readability comes when there is something on the socket.
+	nni_pollable_init(&s->writable);
+	nni_pollable_init(&s->readable);
+
+	return (0);
+}
+
+static void
+rep0_sock_open(void *arg)
+{
+	NNI_ARG_UNUSED(arg);
+}
+
+static void
+rep0_sock_close(void *arg)
+{
+	rep0_sock *s = arg;
+
+	rep0_ctx_close(&s->ctx);
+}
+
+static void
+rep0_pipe_stop(void *arg)
+{
+	rep0_pipe *p = arg;
+
+	nni_aio_stop(&p->aio_send);
+	nni_aio_stop(&p->aio_recv);
+}
+
+static void
+rep0_pipe_fini(void *arg)
+{
+	rep0_pipe *p = arg;
+	nng_msg *  msg;
+
+	if ((msg = nni_aio_get_msg(&p->aio_recv)) != NULL) {
+		nni_aio_set_msg(&p->aio_recv, NULL);
+		nni_msg_free(msg);
+	}
+
+	nni_aio_fini(&p->aio_send);
+	nni_aio_fini(&p->aio_recv);
+}
+
+static int
+rep0_pipe_init(void *arg, nni_pipe *pipe, void *s)
+{
+	rep0_pipe *p = arg;
+
+	nni_aio_init(&p->aio_send, rep0_pipe_send_cb, p);
+	nni_aio_init(&p->aio_recv, rep0_pipe_recv_cb, p);
+
+	NNI_LIST_INIT(&p->sendq, rep0_ctx, sqnode);
+
+	p->id   = nni_pipe_id(pipe);
+	p->pipe = pipe;
+	p->rep  = s;
+	return (0);
+}
+
+static int
+rep0_pipe_start(void *arg)
+{
+	rep0_pipe *p = arg;
+	rep0_sock *s = p->rep;
+	int        rv;
+
+	if (nni_pipe_peer(p->pipe) != NNG_REP0_PEER) {
+		// Peer protocol mismatch.
+		return (NNG_EPROTO);
+	}
+
+	nni_mtx_lock(&s->lk);
+	rv = nni_id_set(&s->pipes, nni_pipe_id(p->pipe), p);
+	nni_mtx_unlock(&s->lk);
+	if (rv != 0) {
+		return (rv);
+	}
+	// By definition, we have not received a request yet on this pipe,
+	// so it cannot cause us to become writable.
+	nni_pipe_recv(p->pipe, &p->aio_recv);
+	return (0);
+}
+
+static void
+rep0_pipe_close(void *arg)
+{
+	rep0_pipe *p = arg;
+	rep0_sock *s = p->rep;
+	rep0_ctx * ctx;
+
+	nni_aio_close(&p->aio_send);
+	nni_aio_close(&p->aio_recv);
+
+	nni_mtx_lock(&s->lk);
+	p->closed = true;
+	if (nni_list_active(&s->recvpipes, p)) {
+		// We are no longer "receivable".
+		nni_list_remove(&s->recvpipes, p);
+	}
+	while ((ctx = nni_list_first(&p->sendq)) != NULL) {
+		nni_aio *aio;
+		nni_msg *msg;
+		// Pipe was closed.  To avoid pushing an error back to the
+		// entire socket, we pretend we completed this successfully.
+		nni_list_remove(&p->sendq, ctx);
+		aio       = ctx->saio;
+		ctx->saio = NULL;
+		msg       = nni_aio_get_msg(aio);
+		nni_aio_set_msg(aio, NULL);
+		nni_aio_finish(aio, 0, nni_msg_len(msg));
+		nni_msg_free(msg);
+	}
+	if (p->id == s->ctx.pipe_id) {
+		// We "can" send.  (Well, not really, but we will happily
+		// accept a message and discard it.)
+		nni_pollable_raise(&s->writable);
+	}
+	nni_id_remove(&s->pipes, nni_pipe_id(p->pipe));
+	nni_mtx_unlock(&s->lk);
+}
+
+static void
+rep0_pipe_send_cb(void *arg)
+{
+	rep0_pipe *p = arg;
+	rep0_sock *s = p->rep;
+	rep0_ctx * ctx;
+	nni_aio *  aio;
+	nni_msg *  msg;
+	size_t     len;
+
+	if (nni_aio_result(&p->aio_send) != 0) {
+		nni_msg_free(nni_aio_get_msg(&p->aio_send));
+		nni_aio_set_msg(&p->aio_send, NULL);
+		nni_pipe_close(p->pipe);
+		return;
+	}
+	nni_mtx_lock(&s->lk);
+	p->busy = false;
+	if ((ctx = nni_list_first(&p->sendq)) == NULL) {
+		// Nothing else to send.
+		if (p->id == s->ctx.pipe_id) {
+			// Mark us ready for the other side to send!
+			nni_pollable_raise(&s->writable);
+		}
+		nni_mtx_unlock(&s->lk);
+		return;
+	}
+
+	nni_list_remove(&p->sendq, ctx);
+	aio        = ctx->saio;
+	ctx->saio  = NULL;
+	ctx->spipe = NULL;
+	p->busy    = true;
+	msg        = nni_aio_get_msg(aio);
+	len        = nni_msg_len(msg);
+	nni_aio_set_msg(aio, NULL);
+	nni_aio_set_msg(&p->aio_send, msg);
+	nni_pipe_send(p->pipe, &p->aio_send);
+
+	nni_mtx_unlock(&s->lk);
+
+	nni_aio_finish_sync(aio, 0, len);
+}
+
+static void
+rep0_cancel_recv(nni_aio *aio, void *arg, int rv)
+{
+	rep0_ctx * ctx = arg;
+	rep0_sock *s   = ctx->sock;
+
+	nni_mtx_lock(&s->lk);
+	if (ctx->raio == aio) {
+		nni_list_remove(&s->recvq, ctx);
+		ctx->raio = NULL;
+		nni_aio_finish_error(aio, rv);
+	}
+	nni_mtx_unlock(&s->lk);
+}
+
+static void
+rep0_ctx_recv(void *arg, nni_aio *aio)
+{
+	rep0_ctx * ctx = arg;
+	rep0_sock *s   = ctx->sock;
+	rep0_pipe *p;
+	size_t     len;
+	nni_msg *  msg;
+
+	if (nni_aio_begin(aio) != 0) {
+		return;
+	}
+	nni_mtx_lock(&s->lk);
+	if ((p = nni_list_first(&s->recvpipes)) == NULL) {
+		int rv;
+		if ((rv = nni_aio_schedule(aio, rep0_cancel_recv, ctx)) != 0) {
+			nni_mtx_unlock(&s->lk);
+			nni_aio_finish_error(aio, rv);
+			return;
+		}
+		if (ctx->raio != NULL) {
+			// Cannot have a second receive operation pending.
+			// This could be ESTATE, or we could cancel the first
+			// with ECANCELED.  We elect the former.
+			nni_mtx_unlock(&s->lk);
+			nni_aio_finish_error(aio, NNG_ESTATE);
+			return;
+		}
+		ctx->raio = aio;
+		nni_list_append(&s->recvq, ctx);
+		nni_mtx_unlock(&s->lk);
+		return;
+	}
+	msg = nni_aio_get_msg(&p->aio_recv);
+	nni_aio_set_msg(&p->aio_recv, NULL);
+	nni_list_remove(&s->recvpipes, p);
+	if (nni_list_empty(&s->recvpipes)) {
+		nni_pollable_clear(&s->readable);
+	}
+	nni_pipe_recv(p->pipe, &p->aio_recv);
+	if ((ctx == &s->ctx) && !p->busy) {
+		nni_pollable_raise(&s->writable);
+	}
+
+	len = nni_msg_header_len(msg);
+	memcpy(ctx->btrace, nni_msg_header(msg), len);
+	ctx->btrace_len = len;
+	ctx->pipe_id    = nni_pipe_id(p->pipe);
+	nni_mtx_unlock(&s->lk);
+
+	nni_msg_header_clear(msg);
+	nni_aio_set_msg(aio, msg);
+	nni_aio_finish(aio, 0, nni_msg_len(msg));
+}
+
+static void
+rep0_pipe_recv_cb(void *arg)
+{
+	rep0_pipe *p = arg;
+	rep0_sock *s = p->rep;
+	rep0_ctx * ctx;
+	nni_msg *  msg;
+	uint8_t *  body;
+	nni_aio *  aio;
+	size_t     len;
+	int        hops;
+	int        ttl;
+
+	if (nni_aio_result(&p->aio_recv) != 0) {
+		nni_pipe_close(p->pipe);
+		return;
+	}
+
+	msg = nni_aio_get_msg(&p->aio_recv);
+	ttl = nni_atomic_get(&s->ttl);
+
+	nni_msg_set_pipe(msg, p->id);
+
+	// Move backtrace from body to header
+	hops = 1;
+	for (;;) {
+		bool end;
+
+		if (hops > ttl) {
+			// This isn't malformed, but it has gone
+			// through too many hops.  Do not disconnect,
+			// because we can legitimately receive messages
+			// with too many hops from devices, etc.
+			goto drop;
+		}
+		hops++;
+		if (nni_msg_len(msg) < 4) {
+			// Peer is speaking garbage. Kick it.
+			nni_msg_free(msg);
+			nni_aio_set_msg(&p->aio_recv, NULL);
+			nni_pipe_close(p->pipe);
+			return;
+		}
+		body = nni_msg_body(msg);
+		end  = ((body[0] & 0x80u) != 0);
+		if (nni_msg_header_append(msg, body, 4) != 0) {
+			// Out of memory, so drop it.
+			goto drop;
+		}
+		nni_msg_trim(msg, 4);
+		if (end) {
+			break;
+		}
+	}
+
+	len = nni_msg_header_len(msg);
+
+	nni_mtx_lock(&s->lk);
+
+	if (p->closed) {
+		// If we are closed, then we can't return data.
+		nni_aio_set_msg(&p->aio_recv, NULL);
+		nni_mtx_unlock(&s->lk);
+		nni_msg_free(msg);
+		return;
+	}
+
+	if ((ctx = nni_list_first(&s->recvq)) == NULL) {
+		// No one waiting to receive yet, holding pattern.
+		nni_list_append(&s->recvpipes, p);
+		nni_pollable_raise(&s->readable);
+		nni_mtx_unlock(&s->lk);
+		return;
+	}
+
+	nni_list_remove(&s->recvq, ctx);
+	aio       = ctx->raio;
+	ctx->raio = NULL;
+	nni_aio_set_msg(&p->aio_recv, NULL);
+	if ((ctx == &s->ctx) && !p->busy) {
+		nni_pollable_raise(&s->writable);
+	}
+
+	// schedule another receive
+	nni_pipe_recv(p->pipe, &p->aio_recv);
+
+	ctx->btrace_len = len;
+	memcpy(ctx->btrace, nni_msg_header(msg), len);
+	nni_msg_header_clear(msg);
+	ctx->pipe_id = p->id;
+
+	nni_mtx_unlock(&s->lk);
+
+	nni_aio_set_msg(aio, msg);
+	nni_aio_finish_sync(aio, 0, nni_msg_len(msg));
+	return;
+
+drop:
+	nni_msg_free(msg);
+	nni_aio_set_msg(&p->aio_recv, NULL);
+	nni_pipe_recv(p->pipe, &p->aio_recv);
+}
+
+static int
+rep0_sock_set_max_ttl(void *arg, const void *buf, size_t sz, nni_opt_type t)
+{
+	rep0_sock *s = arg;
+	int        ttl;
+	int        rv;
+
+	if ((rv = nni_copyin_int(&ttl, buf, sz, 1, NNI_MAX_MAX_TTL, t)) == 0) {
+		nni_atomic_set(&s->ttl, ttl);
+	}
+	return (rv);
+}
+
+static int
+rep0_sock_get_max_ttl(void *arg, void *buf, size_t *szp, nni_opt_type t)
+{
+	rep0_sock *s = arg;
+
+	return (nni_copyout_int(nni_atomic_get(&s->ttl), buf, szp, t));
+}
+
+static int
+rep0_sock_get_sendfd(void *arg, void *buf, size_t *szp, nni_opt_type t)
+{
+	rep0_sock *s = arg;
+	int        rv;
+	int        fd;
+
+	if ((rv = nni_pollable_getfd(&s->writable, &fd)) != 0) {
+		return (rv);
+	}
+	return (nni_copyout_int(fd, buf, szp, t));
+}
+
+static int
+rep0_sock_get_recvfd(void *arg, void *buf, size_t *szp, nni_opt_type t)
+{
+	rep0_sock *s = arg;
+	int        rv;
+	int        fd;
+
+	if ((rv = nni_pollable_getfd(&s->readable, &fd)) != 0) {
+		return (rv);
+	}
+
+	return (nni_copyout_int(fd, buf, szp, t));
+}
+
+static void
+rep0_sock_send(void *arg, nni_aio *aio)
+{
+	rep0_sock *s = arg;
+
+	rep0_ctx_send(&s->ctx, aio);
+}
+
+static void
+rep0_sock_recv(void *arg, nni_aio *aio)
+{
+	rep0_sock *s = arg;
+
+	rep0_ctx_recv(&s->ctx, aio);
+}
+
+// This is the global protocol structure -- our linkage to the core.
+// This should be the only global non-static symbol in this file.
+static nni_proto_pipe_ops rep0_pipe_ops = {
+	.pipe_size  = sizeof(rep0_pipe),
+	.pipe_init  = rep0_pipe_init,
+	.pipe_fini  = rep0_pipe_fini,
+	.pipe_start = rep0_pipe_start,
+	.pipe_close = rep0_pipe_close,
+	.pipe_stop  = rep0_pipe_stop,
+};
+
+static nni_proto_ctx_ops rep0_ctx_ops = {
+	.ctx_size = sizeof(rep0_ctx),
+	.ctx_init = rep0_ctx_init,
+	.ctx_fini = rep0_ctx_fini,
+	.ctx_send = rep0_ctx_send,
+	.ctx_recv = rep0_ctx_recv,
+};
+
+static nni_option rep0_sock_options[] = {
+	{
+	    .o_name = NNG_OPT_MAXTTL,
+	    .o_get  = rep0_sock_get_max_ttl,
+	    .o_set  = rep0_sock_set_max_ttl,
+	},
+	{
+	    .o_name = NNG_OPT_RECVFD,
+	    .o_get  = rep0_sock_get_recvfd,
+	},
+	{
+	    .o_name = NNG_OPT_SENDFD,
+	    .o_get  = rep0_sock_get_sendfd,
+	},
+	// terminate list
+	{
+	    .o_name = NULL,
+	},
+};
+
+static nni_proto_sock_ops rep0_sock_ops = {
+	.sock_size    = sizeof(rep0_sock),
+	.sock_init    = rep0_sock_init,
+	.sock_fini    = rep0_sock_fini,
+	.sock_open    = rep0_sock_open,
+	.sock_close   = rep0_sock_close,
+	.sock_options = rep0_sock_options,
+	.sock_send    = rep0_sock_send,
+	.sock_recv    = rep0_sock_recv,
+};
+
+static nni_proto rep0_proto = {
+	.proto_version  = NNI_PROTOCOL_VERSION,
+	.proto_self     = { NNG_REP0_SELF, NNG_REP0_SELF_NAME },
+	.proto_peer     = { NNG_REP0_PEER, NNG_REP0_PEER_NAME },
+	.proto_flags    = NNI_PROTO_FLAG_SNDRCV,
+	.proto_sock_ops = &rep0_sock_ops,
+	.proto_pipe_ops = &rep0_pipe_ops,
+	.proto_ctx_ops  = &rep0_ctx_ops,
+};
+
+int
+nng_rep0_open(nng_socket *sidp)
+{
+	return (nni_proto_open(sidp, &rep0_proto));
+}