fixes #595 mutex leak and other minor errors in TCP

fixes #596 POSIX IPC should move away from pipedesc/epdesc
fixes #598 TLS and TCP listeners could support NNG_OPT_LOCADDR
fixes #594 Windows IPC should use "new style" win_io code.
fixes #597 macOS could support PEER PID

This large change set cleans up the IPC support on Windows and
POSIX.  This has the beneficial impact of significantly reducing
the complexity of the code, reducing locking, increasing
concurrency (multiple dial and accepts can be outstanding now),
reducing context switches (we complete thins synchronously now).

While here we have added some missing option support, and fixed a
few more bugs that we found in the TCP code changes from last week.

1 files changed, 82 insertions, 61 deletions

diff --git a/src/core/platform.h b/src/core/platform.h
index 5045b172..2ae0fd0b 100644
--- a/src/core/platform.h
+++ b/src/core/platform.h
@@ -215,7 +215,7 @@ typedef struct nni_tcp_listener nni_tcp_listener;
 
 extern void nni_tcp_conn_fini(nni_tcp_conn *);
 
-// nni_tcp_dialer_close closes the dialer, which might actually be
+// nni_tcp_conn_close closes the connection, which might actually be
 // implemented as a shutdown() call.
 // Further operations on it should return NNG_ECLOSED.
 extern void nni_tcp_conn_close(nni_tcp_conn *);
@@ -248,7 +248,7 @@ extern int nni_tcp_conn_set_nodelay(nni_tcp_conn *, bool);
 // keepalive probes.  Tuning of these keepalives is current unsupported.
 extern int nni_tcp_conn_set_keepalive(nni_tcp_conn *, bool);
 
-// nni_tcp_listener_init creates a new dialer object.
+// nni_tcp_dialer_init creates a new dialer object.
 extern int nni_tcp_dialer_init(nni_tcp_dialer **);
 
 // nni_tcp_dialer_fini finalizes the dialer, closing it and freeing
@@ -311,81 +311,102 @@ extern void nni_udp_resolv(const char *, const char *, int, int, nni_aio *);
 // IPC (UNIX Domain Sockets & Named Pipes) Support.
 //
 
-typedef struct nni_plat_ipc_ep   nni_plat_ipc_ep;
-typedef struct nni_plat_ipc_pipe nni_plat_ipc_pipe;
+typedef struct nni_ipc_conn     nni_ipc_conn;
+typedef struct nni_ipc_dialer   nni_ipc_dialer;
+typedef struct nni_ipc_listener nni_ipc_listener;
 
-// nni_plat_ipc_ep_init creates a new endpoint associated with the url.
-// The final field is the mode, either for dialing (NNI_EP_MODE_DIAL) or
-// listening (NNI_EP_MODE_LISTEN).
-extern int nni_plat_ipc_ep_init(nni_plat_ipc_ep **, const nni_sockaddr *, int);
+// nni_ipc_conn_fini disposes of the connection.
+extern void nni_ipc_conn_fini(nni_ipc_conn *);
 
-// nni_plat_ipc_ep_fini closes the endpoint and releases resources.
-extern void nni_plat_ipc_ep_fini(nni_plat_ipc_ep *);
+// nni_ipc_conn_close closes the connection, which might actually be
+// implemented as a shutdown() call.
+// Further operations on it should return NNG_ECLOSED.
+extern void nni_ipc_conn_close(nni_ipc_conn *);
 
-// nni_plat_ipc_ep_close closes the endpoint; this might not close the
-// actual underlying socket, but it should call shutdown on it.
-// Further operations on the pipe should return NNG_ECLOSED.
-extern void nni_plat_ipc_ep_close(nni_plat_ipc_ep *);
+// nni_ipc_conn_send sends data in the iov buffers to the peer.
+// The platform may modify the iovs.
+extern void nni_ipc_conn_send(nni_ipc_conn *, nni_aio *);
 
-// nni_plat_ipc_listen creates an IPC socket in listening mode, bound
-// to the specified path.
-extern int nni_plat_ipc_ep_listen(nni_plat_ipc_ep *);
+// nni_ipc_conn_recv receives data into the buffers provided by the
+// I/O vector (iovs).  The platform should attempt to scatter the received
+// data into the iovs if possible.
+//
+// It is possible for the reader to return less data than is requested,
+// in which case the caller is responsible for resubmitting.  The platform
+// must not return "zero" data however.  (It is an error to attempt to
+// receive zero bytes.)  The platform may modify the iovs.
+extern void nni_ipc_conn_recv(nni_ipc_conn *, nni_aio *);
 
-// nni_plat_ipc_ep_accept starts an accept to receive an incoming connection.
-// An accepted connection will be passed back in the a_pipe member.
-extern void nni_plat_ipc_ep_accept(nni_plat_ipc_ep *, nni_aio *);
+// nni_ipc_conn_get_peer_uid obtains the peer user id, if possible.
+// NB: Only POSIX systems support user IDs.
+extern int nni_ipc_conn_get_peer_uid(nni_ipc_conn *, uint64_t *);
 
-// nni_plat_ipc_connect is the client side.
-// An accepted connection will be passed back in the a_pipe member.
-extern void nni_plat_ipc_ep_connect(nni_plat_ipc_ep *, nni_aio *);
+// nni_ipc_conn_get_peer_gid obtains the peer group id, if possible.
+// NB: Only POSIX systems support group IDs.
+extern int nni_ipc_conn_get_peer_gid(nni_ipc_conn *, uint64_t *);
 
-// nni_plat_ipc_ep_set_security_descriptor sets the Windows security
-// descriptor. This is *only* supported for Windows platforms.  All
-// others return NNG_ENOTSUP.  The void argument is a pointer to
-// a SECURITY_DESCRIPTOR object, and must be valid.
-extern int nni_plat_ipc_ep_set_security_descriptor(nni_plat_ipc_ep *, void *);
+// nni_ipc_conn_get_peer_pid obtains the peer process id, if possible.
+extern int nni_ipc_conn_get_peer_pid(nni_ipc_conn *, uint64_t *);
 
-// nni_plat_ipc_ep_set_permissions sets UNIX style permissions
-// on the named pipes.  This basically just does a chmod() on the
-// named pipe, and is only supported o the server side, and only on
-// systems that support this (POSIX, not Windows).  Note that changing
-// ownership is not supported at this time.  Most systems use only
-// 16-bits, the lower 12 of which are user, group, and other, e.g.
-// 0640 gives read/write access to user, read to group, and prevents
-// any other user from accessing it.  This option only has meaning
-// for listeners, on dialers it is ignored.
-extern int nni_plat_ipc_ep_set_permissions(nni_plat_ipc_ep *, uint32_t);
+// nni_ipc_conn_get_peer_zoneid obtains the peer zone id, if possible.
+// NB: Only illumos & SunOS systems have the notion of "zones".
+extern int nni_ipc_conn_get_peer_zoneid(nni_ipc_conn *, uint64_t *);
+
+// nni_ipc_dialer_init creates a new dialer object.
+extern int nni_ipc_dialer_init(nni_ipc_dialer **);
 
-// nni_plat_ipc_pipe_fini closes the pipe, and releases all resources
-// associated with it.
-extern void nni_plat_ipc_pipe_fini(nni_plat_ipc_pipe *);
+// nni_ipc_dialer_fini finalizes the dialer, closing it and freeing
+// all resources.
+extern void nni_ipc_dialer_fini(nni_ipc_dialer *);
 
-// nni_plat_ipc_pipe_close closes the socket, or at least shuts it down.
-// Further operations on the pipe should return NNG_ECLOSED.
-extern void nni_plat_ipc_pipe_close(nni_plat_ipc_pipe *);
+// nni_ipc_dialer_close closes the dialer.
+// Further operations on it should return NNG_ECLOSED.  Any in-progress
+// connection will be aborted.
+extern void nni_ipc_dialer_close(nni_ipc_dialer *);
 
-// nni_plat_ipc_pipe_send sends data in the iov buffers to the peer.
-// The platform may modify the iovs.
-extern void nni_plat_ipc_pipe_send(nni_plat_ipc_pipe *, nni_aio *);
+// nni_ipc_dialer_dial attempts to create an outgoing connection,
+// asynchronously, to the address specified. On success, the first (and only)
+// output will be an nni_ipc_conn * associated with the remote server.
+extern void nni_ipc_dialer_dial(
+    nni_ipc_dialer *, const nni_sockaddr *, nni_aio *);
 
-// nni_plat_ipc_pipe_recv recvs data into the buffers provided by the iovs.
-// The platform may modify the iovs.
-extern void nni_plat_ipc_pipe_recv(nni_plat_ipc_pipe *, nni_aio *);
+// nni_ipc_listener_init creates a new listener object, unbound.
+extern int nni_ipc_listener_init(nni_ipc_listener **);
 
-// nni_plat_ipc_pipe_get_peer_uid obtains the peer user id, if possible.
-// NB: Only POSIX systems support user IDs.
-extern int nni_plat_ipc_pipe_get_peer_uid(nni_plat_ipc_pipe *, uint64_t *);
+// nni_ipc_listener_fini frees the listener and all associated resources.
+// It implictly closes the listener as well.
+extern void nni_ipc_listener_fini(nni_ipc_listener *);
 
-// nni_plat_ipc_pipe_get_peer_gid obtains the peer group id, if possible.
-// NB: Only POSIX systems support group IDs.
-extern int nni_plat_ipc_pipe_get_peer_gid(nni_plat_ipc_pipe *, uint64_t *);
+// nni_ipc_listener_close closes the listener.  This will unbind
+// any bound socket, and further operations will result in NNG_ECLOSED.
+extern void nni_ipc_listener_close(nni_ipc_listener *);
 
-// nni_plat_ipc_pipe_get_peer_pid obtains the peer process id, if possible.
-extern int nni_plat_ipc_pipe_get_peer_pid(nni_plat_ipc_pipe *, uint64_t *);
+// nni_ipc_listener_listen creates the socket in listening mode, bound
+// to the specified address.  Unlike TCP, this address does not change.
+extern int nni_ipc_listener_listen(nni_ipc_listener *, const nni_sockaddr *);
 
-// nni_plat_ipc_pipe_get_peer_zoneid obtains the peer zone id, if possible.
-// NB: Only illumos & SunOS systems have the notion of "zones".
-extern int nni_plat_ipc_pipe_get_peer_zoneid(nni_plat_ipc_pipe *, uint64_t *);
+// nni_ipc_listener_accept accepts in incoming connect, asynchronously.
+// On success, the first (and only) output will be an nni_ipc_conn *
+// associated with the remote peer.
+extern void nni_ipc_listener_accept(nni_ipc_listener *, nni_aio *);
+
+// nni_ipc_listener_set_permissions sets UNIX style permissions
+// on the named pipes.  This basically just does a chmod() on the
+// named pipe, and is only supported o the server side, and only on
+// systems that support this (POSIX, not Windows).  Note that changing
+// ownership is not supported at this time.  Most systems use only
+// 16-bits, the lower 12 of which are user, group, and other, e.g.
+// 0640 gives read/write access to user, read to group, and prevents
+// any other user from accessing it.  On platforms without this support,
+// ENOTSUP is returned.
+extern int nni_ipc_listener_set_permissions(nni_ipc_listener *, int);
+
+// nni_ipc_listener_set_security_descriptor sets the Windows security
+// descriptor. This is *only* supported for Windows platforms.  All
+// others return NNG_ENOTSUP.  The void argument is a pointer to
+// a SECURITY_DESCRIPTOR object, and must be valid.
+extern int nni_ipc_listener_set_security_descriptor(
+    nni_ipc_listener *, void *);
 
 //
 // UDP support. UDP is not connection oriented, and only has the notion