fixes #2 Websocket transport

This is a rather large changeset -- it fundamentally adds websocket
transport, but as part of this changeset we added a generic framework
for both HTTP and websocket.  We also made some supporting changes to
the core, such as changing the way timeouts work for AIOs and adding
additional state keeping for AIOs, and adding a common framework for
deferred finalization (to avoid certain kinds of circular deadlocks
during resource cleanup).  We also invented a new initialization framework
so that we can avoid wiring in knowledge about them into the master
initialization framework.

The HTTP framework is not yet complete, but it is good enough for simple
static serving and building additional services on top of -- including
websocket.  We expect both websocket and HTTP support to evolve
considerably, and so these are not part of the public API yet.

Property support for the websocket transport (in particular address
properties) is still missing, as is support for TLS.

The websocket transport here is a bit more robust than the original
nanomsg implementation, as it supports multiple sockets listening at
the same port sharing the same HTTP server instance, discriminating
between them based on URI (and possibly the virtual host).

Websocket is enabled by default at present, and work to conditionalize
HTTP and websocket further (to minimize bloat) is still pending.

1 files changed, 63 insertions, 0 deletions

diff --git a/src/supplemental/websocket/websocket.h b/src/supplemental/websocket/websocket.h
new file mode 100644
index 00000000..25add55e
--- /dev/null
+++ b/src/supplemental/websocket/websocket.h
@@ -0,0 +1,63 @@
+//
+// Copyright 2017 Staysail Systems, Inc. <info@staysail.tech>
+// 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_SUPPLEMENTAL_WEBSOCKET_WEBSOCKET_H
+#define NNG_SUPPLEMENTAL_WEBSOCKET_WEBSOCKET_H
+
+// Pre-defined types for some prototypes.  These are from other subsystems.
+typedef struct nni_tls_config nni_tls_config;
+typedef struct nni_http_req   nni_http_req;
+typedef struct nni_http_res   nni_http_res;
+
+typedef struct nni_ws          nni_ws;
+typedef struct nni_ws_listener nni_ws_listener;
+typedef struct nni_ws_dialer   nni_ws_dialer;
+
+typedef int (*nni_ws_listen_hook)(void *, nni_http_req *, nni_http_res *);
+
+// Specify URL as ws://[<host>][:port][/path]
+// If host is missing, INADDR_ANY is assumed.  If port is missing,
+// then either 80 or 443 are assumed.  Note that ws:// means listen
+// on INADDR_ANY port 80, with path "/".  For connect side, INADDR_ANY
+// makes no sense.  (TBD: return NNG_EADDRINVAL, or try loopback?)
+
+extern int  nni_ws_listener_init(nni_ws_listener **, const char *);
+extern void nni_ws_listener_fini(nni_ws_listener *);
+extern void nni_ws_listener_close(nni_ws_listener *);
+extern int  nni_ws_listener_proto(nni_ws_listener *, const char *);
+extern int  nni_ws_listener_listen(nni_ws_listener *);
+extern void nni_ws_listener_accept(nni_ws_listener *, nni_aio *);
+extern void nni_ws_listener_hook(
+    nni_ws_listener *, nni_ws_listen_hook, void *);
+extern void nni_ws_listener_tls(nni_ws_listener *, nni_tls_config *);
+
+extern int  nni_ws_dialer_init(nni_ws_dialer **, const char *);
+extern void nni_ws_dialer_fini(nni_ws_dialer *);
+extern void nni_ws_dialer_close(nni_ws_dialer *);
+extern int  nni_ws_dialer_proto(nni_ws_dialer *, const char *);
+extern int  nni_ws_dialer_header(nni_ws_dialer *, const char *, const char *);
+extern void nni_ws_dialer_dial(nni_ws_dialer *, nni_aio *);
+
+// Dialer does not get a hook chance, as it can examine the request and reply
+// after dial is done; this is not a 3-way handshake, so the dialer does
+// not confirm the server's response at the HTTP level.  (It can still issue
+// a websocket close).
+
+extern void          nni_ws_send_msg(nni_ws *, nni_aio *);
+extern void          nni_ws_recv_msg(nni_ws *, nni_aio *);
+extern nni_http_res *nni_ws_response(nni_ws *);
+extern nni_http_req *nni_ws_request(nni_ws *);
+extern void          nni_ws_close(nni_ws *);
+extern void          nni_ws_close_error(nni_ws *, uint16_t);
+extern void          nni_ws_fini(nni_ws *);
+
+// The implementation will send periodic PINGs, and respond with PONGs.
+
+#endif // NNG_SUPPLEMENTAL_WEBSOCKET_WEBSOCKET_H
\ No newline at end of file