fixes #523 dialers could support multiple outstanding dial requests

fixes #179 DNS resolution should be done at connect time
fixes #586 Windows IO completion port work could be better
fixes #339 Windows iocp could use synchronous completions
fixes #280 TCP abstraction improvements

This is a rather monstrous set of changes, which refactors TCP, and
the underlying Windows I/O completion path logic, in order to obtain
a cleaner, simpler API, with support for asynchronous DNS lookups performed
on connect rather than initialization time, the ability to have multiple
connects or accepts pending, as well as fewer extraneous function calls.

The Windows code also benefits from greatly reduced context switching,
fewer lock operations performed, and a reduced number of system calls
on the hot code path.  (We use automatic event resetting instead of manual.)

Some dead code was removed as well, and a few potential edge case leaks
on failure paths (in the websocket code) were plugged.

Note that all TCP based transports benefit from this work. The IPC code
on Windows still uses the legacy IOCP for now, as does the UDP code (used
for ZeroTier.)  We will be converting those soon too.

1 files changed, 24 insertions, 0 deletions

diff --git a/src/platform/windows/win_impl.h b/src/platform/windows/win_impl.h
index 263a322b..93e45423 100644
--- a/src/platform/windows/win_impl.h
+++ b/src/platform/windows/win_impl.h
@@ -80,6 +80,17 @@ struct nni_win_event {
 	nni_win_event_ops ops;
 };
 
+typedef struct nni_win_io nni_win_io;
+typedef void (*nni_win_io_cb)(nni_win_io *, int, size_t);
+
+struct nni_win_io {
+	OVERLAPPED    olpd;
+	HANDLE        f;
+	void *        ptr;
+	nni_aio *     aio;
+	nni_win_io_cb cb;
+};
+
 struct nni_plat_flock {
 	HANDLE h;
 };
@@ -94,6 +105,13 @@ extern void nni_win_event_complete(nni_win_event *, int);
 
 extern int nni_win_iocp_register(HANDLE);
 
+extern int  nni_win_tcp_conn_init(nni_tcp_conn **, SOCKET);
+extern void nni_win_tcp_conn_set_addrs(
+    nni_tcp_conn *, const SOCKADDR_STORAGE *, const SOCKADDR_STORAGE *);
+
+extern int  nni_win_io_sysinit(void);
+extern void nni_win_io_sysfini(void);
+
 extern int  nni_win_iocp_sysinit(void);
 extern void nni_win_iocp_sysfini(void);
 
@@ -109,6 +127,12 @@ extern void nni_win_udp_sysfini(void);
 extern int  nni_win_resolv_sysinit(void);
 extern void nni_win_resolv_sysfini(void);
 
+extern int  nni_win_io_init(nni_win_io *, HANDLE, nni_win_io_cb, void *);
+extern void nni_win_io_fini(nni_win_io *);
+extern void nni_win_io_cancel(nni_win_io *);
+
+extern int nni_win_io_register(HANDLE);
+
 extern int nni_win_sockaddr2nn(nni_sockaddr *, const SOCKADDR_STORAGE *);
 extern int nni_win_nn2sockaddr(SOCKADDR_STORAGE *, const nni_sockaddr *);