Add new PAIR_V1 protocol.

The PAIR_V1 protocol supports both raw and cooked modes, and has loop
prevention included.  It also has a polyamorous mode, wherein it allows
multiple connections to be established.  In polyamorous mode (set by
an option), the sender requests a paritcular pipe by setting it on the
message.

We default to PAIR_V1 now.

1 files changed, 297 insertions, 0 deletions

diff --git a/src/protocol/pair/pair_v0.c b/src/protocol/pair/pair_v0.c
new file mode 100644
index 00000000..a0e907f2
--- /dev/null
+++ b/src/protocol/pair/pair_v0.c
@@ -0,0 +1,297 @@
+//
+// 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"
+
+// Pair protocol.  The PAIR protocol is a simple 1:1 messaging pattern.
+// While a peer is connected to the server, all other peer connection
+// attempts are discarded.
+
+typedef struct pair0_pipe pair0_pipe;
+typedef struct pair0_sock pair0_sock;
+
+static void pair0_send_cb(void *);
+static void pair0_recv_cb(void *);
+static void pair0_getq_cb(void *);
+static void pair0_putq_cb(void *);
+static void pair0_pipe_fini(void *);
+
+// pair0_sock is our per-socket protocol private structure.
+struct pair0_sock {
+	nni_sock *  nsock;
+	pair0_pipe *ppipe;
+	nni_msgq *  uwq;
+	nni_msgq *  urq;
+	int         raw;
+	nni_mtx     mtx;
+};
+
+// An pair0_pipe is our per-pipe protocol private structure.  We keep
+// one of these even though in theory we'd only have a single underlying
+// pipe.  The separate data structure is more like other protocols that do
+// manage multiple pipes.
+struct pair0_pipe {
+	nni_pipe *  npipe;
+	pair0_sock *psock;
+	nni_aio     aio_send;
+	nni_aio     aio_recv;
+	nni_aio     aio_getq;
+	nni_aio     aio_putq;
+};
+
+static int
+pair0_sock_init(void **sp, nni_sock *nsock)
+{
+	pair0_sock *s;
+	int         rv;
+
+	if ((s = NNI_ALLOC_STRUCT(s)) == NULL) {
+		return (NNG_ENOMEM);
+	}
+	if ((rv = nni_mtx_init(&s->mtx)) != 0) {
+		NNI_FREE_STRUCT(s);
+		return (rv);
+	}
+	s->nsock = nsock;
+	s->ppipe = NULL;
+	s->raw   = 0;
+	s->uwq   = nni_sock_sendq(nsock);
+	s->urq   = nni_sock_recvq(nsock);
+	*sp      = s;
+	return (0);
+}
+
+static void
+pair0_sock_fini(void *arg)
+{
+	pair0_sock *s = arg;
+
+	nni_mtx_fini(&s->mtx);
+	NNI_FREE_STRUCT(s);
+}
+
+static int
+pair0_pipe_init(void **pp, nni_pipe *npipe, void *psock)
+{
+	pair0_pipe *p;
+	int         rv;
+
+	if ((p = NNI_ALLOC_STRUCT(p)) == NULL) {
+		return (NNG_ENOMEM);
+	}
+	if (((rv = nni_aio_init(&p->aio_send, pair0_send_cb, p)) != 0) ||
+	    ((rv = nni_aio_init(&p->aio_recv, pair0_recv_cb, p)) != 0) ||
+	    ((rv = nni_aio_init(&p->aio_getq, pair0_getq_cb, p)) != 0) ||
+	    ((rv = nni_aio_init(&p->aio_putq, pair0_putq_cb, p)) != 0)) {
+		pair0_pipe_fini(p);
+	} else {
+		p->npipe = npipe;
+		p->psock = psock;
+		*pp      = p;
+	}
+	return (rv);
+}
+
+static void
+pair0_pipe_fini(void *arg)
+{
+	pair0_pipe *p = arg;
+
+	nni_aio_fini(&p->aio_send);
+	nni_aio_fini(&p->aio_recv);
+	nni_aio_fini(&p->aio_putq);
+	nni_aio_fini(&p->aio_getq);
+	NNI_FREE_STRUCT(p);
+}
+
+static int
+pair0_pipe_start(void *arg)
+{
+	pair0_pipe *p = arg;
+	pair0_sock *s = p->psock;
+
+	nni_mtx_lock(&s->mtx);
+	if (s->ppipe != NULL) {
+		nni_mtx_unlock(&s->mtx);
+		return (NNG_EBUSY); // Already have a peer, denied.
+	}
+	s->ppipe = p;
+	nni_mtx_unlock(&s->mtx);
+
+	// Schedule a getq on the upper, and a read from the pipe.
+	// Each of these also sets up another hold on the pipe itself.
+	nni_msgq_aio_get(s->uwq, &p->aio_getq);
+	nni_pipe_recv(p->npipe, &p->aio_recv);
+
+	return (0);
+}
+
+static void
+pair0_pipe_stop(void *arg)
+{
+	pair0_pipe *p = arg;
+	pair0_sock *s = p->psock;
+
+	nni_aio_cancel(&p->aio_send, NNG_ECANCELED);
+	nni_aio_cancel(&p->aio_recv, NNG_ECANCELED);
+	nni_aio_cancel(&p->aio_putq, NNG_ECANCELED);
+	nni_aio_cancel(&p->aio_getq, NNG_ECANCELED);
+
+	nni_mtx_lock(&s->mtx);
+	if (s->ppipe == p) {
+		s->ppipe = NULL;
+	}
+	nni_mtx_unlock(&s->mtx);
+}
+
+static void
+pair0_recv_cb(void *arg)
+{
+	pair0_pipe *p = arg;
+	pair0_sock *s = p->psock;
+	nni_msg *   msg;
+
+	if (nni_aio_result(&p->aio_recv) != 0) {
+		nni_pipe_stop(p->npipe);
+		return;
+	}
+
+	msg               = p->aio_recv.a_msg;
+	p->aio_putq.a_msg = msg;
+	p->aio_recv.a_msg = NULL;
+
+	nni_msg_set_pipe(msg, nni_pipe_id(p->npipe));
+	nni_msgq_aio_put(s->urq, &p->aio_putq);
+}
+
+static void
+pair0_putq_cb(void *arg)
+{
+	pair0_pipe *p = arg;
+
+	if (nni_aio_result(&p->aio_putq) != 0) {
+		nni_msg_free(p->aio_putq.a_msg);
+		p->aio_putq.a_msg = NULL;
+		nni_pipe_stop(p->npipe);
+		return;
+	}
+	nni_pipe_recv(p->npipe, &p->aio_recv);
+}
+
+static void
+pair0_getq_cb(void *arg)
+{
+	pair0_pipe *p = arg;
+	pair0_sock *s = p->psock;
+
+	if (nni_aio_result(&p->aio_getq) != 0) {
+		nni_pipe_stop(p->npipe);
+		return;
+	}
+
+	p->aio_send.a_msg = p->aio_getq.a_msg;
+	p->aio_getq.a_msg = NULL;
+	nni_pipe_send(p->npipe, &p->aio_send);
+}
+
+static void
+pair0_send_cb(void *arg)
+{
+	pair0_pipe *p = arg;
+	pair0_sock *s = p->psock;
+
+	if (nni_aio_result(&p->aio_send) != 0) {
+		nni_msg_free(p->aio_send.a_msg);
+		p->aio_send.a_msg = NULL;
+		nni_pipe_stop(p->npipe);
+		return;
+	}
+
+	nni_msgq_aio_get(s->uwq, &p->aio_getq);
+}
+
+static void
+pair0_sock_open(void *arg)
+{
+	NNI_ARG_UNUSED(arg);
+}
+
+static void
+pair0_sock_close(void *arg)
+{
+	NNI_ARG_UNUSED(arg);
+}
+
+static int
+pair0_sock_setopt(void *arg, int opt, const void *buf, size_t sz)
+{
+	pair0_sock *s = arg;
+	int         rv;
+
+	switch (opt) {
+	case NNG_OPT_RAW:
+		rv = nni_setopt_int(&s->raw, buf, sz, 0, 1);
+		break;
+	default:
+		rv = NNG_ENOTSUP;
+	}
+	return (rv);
+}
+
+static int
+pair0_sock_getopt(void *arg, int opt, void *buf, size_t *szp)
+{
+	pair0_sock *s = arg;
+	int         rv;
+
+	switch (opt) {
+	case NNG_OPT_RAW:
+		rv = nni_getopt_int(&s->raw, buf, szp);
+		break;
+	default:
+		rv = NNG_ENOTSUP;
+	}
+	return (rv);
+}
+
+static nni_proto_pipe_ops pair0_pipe_ops = {
+	.pipe_init  = pair0_pipe_init,
+	.pipe_fini  = pair0_pipe_fini,
+	.pipe_start = pair0_pipe_start,
+	.pipe_stop  = pair0_pipe_stop,
+};
+
+static nni_proto_sock_ops pair0_sock_ops = {
+	.sock_init   = pair0_sock_init,
+	.sock_fini   = pair0_sock_fini,
+	.sock_open   = pair0_sock_open,
+	.sock_close  = pair0_sock_close,
+	.sock_setopt = pair0_sock_setopt,
+	.sock_getopt = pair0_sock_getopt,
+};
+
+// Legacy protocol (v0)
+static nni_proto pair0_proto = {
+	.proto_version  = NNI_PROTOCOL_VERSION,
+	.proto_self     = { NNG_PROTO_PAIR_V0, "pair" },
+	.proto_peer     = { NNG_PROTO_PAIR_V0, "pair" },
+	.proto_flags    = NNI_PROTO_FLAG_SNDRCV,
+	.proto_sock_ops = &pair0_sock_ops,
+	.proto_pipe_ops = &pair0_pipe_ops,
+};
+
+int
+nng_pair0_open(nng_socket *sidp)
+{
+	return (nni_proto_open(sidp, &pair0_proto));
+}