lws-meta

CMakeLists.txt

@@ -1443,6 +1443,8 @@ if (NOT LWS_WITHOUT_TESTAPPS)
 		endmacro()
 		
 
+		create_plugin(protocol_lws_meta
+			      "plugins/protocol_lws_meta.c" "" "")
 		create_plugin(protocol_dumb_increment
 			      "plugins/protocol_dumb_increment.c" "" "")
 		create_plugin(protocol_lws_mirror

README.lws-meta.md

@@ -0,0 +1,192 @@
+# lws-meta protocol
+
+lws-meta is a lightweight ws subprotocol that accepts other ws connections
+to the same server inside it and multiplexes their access to the connection.
+
+```
+  Client                                                    Server
+ 
+  conn1: \                                                / :conn1
+  conn2:  =   mux ------ lws-meta ws protocol ----- mux  =  :conn2
+  conn3: /                                                \ :conn3
+```
+
+You may have n client ws connections back to the server, but you now
+only have one tcp connection (and one SSL wrapper if using SSL) instead
+of n of those.
+
+If you currently make multiple ws connections back to the server, so you
+can have different protocols active in one webpage, this if for you.
+
+ - The subprotocol code for the connections inside a lws-meta connection
+   need zero changes from being a normal ws connection.  It is unaware
+   it is inside an lws-meta parent connection.
+
+ - The traffic on the lws-meta connection is indistinguishable from
+   standard ws traffic, so intermediaries won't object to it
+
+ - The multiplexing is done in the protocol, **not by an extension**.  So
+   it's compatible with all browsers.
+
+ - Javascript helper code is provided to very simply use lws-meta
+   protocol instead of direct connections.  The lws test server has
+   been converted to use this by default.
+
+# Converting your server
+
+1) include the provided lws-meta plugin (plugins/protocl_lws_meta.c) as an
+active protocol for your server.  You can do that using runtime plugins, or
+include the plugin sources into your server at build-time.  The lws test
+server uses the latter approach.
+
+That's all you need to do on the server side.
+
+# Converting your browser JS
+
+1) import lws-common.js
+
+2) Instantiate a parent lws-meta connection object
+
+```
+var lws_meta = new lws_meta_ws();
+```
+
+3) Connect the lws-meta object to your server
+
+```
+lws_meta.new_parent(get_appropriate_ws_url("?mirror=" + mirror_name));
+```
+
+4) Convert your actual ws connections to go via the lws_meta object
+
+```
+var my_ws = lws_meta.new_ws("", "dumb-increment-protocol");
+```
+
+The first arg is the URL path, the second arg is the ws protocol you want.
+
+That's it.  my_ws will get `onopen()`, `onmessage()` etc calls as before.
+
+# lws-meta wire protocol
+
+lws-meta works by adding some bytes at the start of a message indicating
+which channel the message applies to.
+
+Channel messages are atomic on the wire.  The reason is if we tried to
+intersperse other channel fragments between one channels message fragments,
+an intermediary would observe violations of the ws framing rule about
+having to start a message with TEXT or BINARY, and use only CONTINUATION
+for the subsequent fragments.  Eg
+
+```
+  [ ch1 TEXT NOFIN ] [ ch2 BINARY FIN ] [ ch1 CONTINUATION FIN ]
+```
+
+is illegal to an observer that doesn't understand lws-meta headers in the
+packet payloads.  So to avoid this situation, only complete messages may
+be sent from one subchannel in each direction at a time.
+
+Consequently, only the first fragment of each message is modified to
+have the extra two bytes identifying the subchannel it is aimed at, since
+the rest of the message from the same subchannel is defined to follow.
+
+If it makes latencies, modify the protocol sending large messages to
+send smaller messages, so the transmission of messages from other channels
+can be sent inbetween the smaller messages.
+
+## lws-meta commands
+
+1) CSTRING indicates a string terminated by 0x00 byte
+
+2) Channel IDs are sent with 0x20 added to them, to guarantee valid UTF-8
+
+### 0x41: RX: LWS_META_CMD_OPEN_SUBCHANNEL
+
+   - CSTRING: protocol name
+   - CSTRING: url
+   - CSTRING: cookie (7 bytes max)
+
+Client is requesting to open a new channel with the given protocol name,
+at the given url.  The cookie (eg, channel name) is only used in
+LWS_META_CMD_OPEN_RESULT, when the channel id is assigned, so it is
+applied to the right channel.
+
+### 0x42: TX: LWS_META_CMD_OPEN_RESULT
+
+   - CSTRING cookie
+   - BYTE channel id (0 indicates failed)
+   - CSTRING: selected protocol name
+
+The server is informing the client of the results of a previous
+open request.  The cookie the client sent to identify the request
+is returned along with a channel id to be used subsequently.  If
+the channel ID is 0 (after subtracting the transport offset of
+0x20) then the open request has failed.
+
+### 0x43: TX: LWS_META_CMD_CLOSE_NOTIFY
+
+   - BYTE channel id
+   - BYTE: payload length + 0x20
+   - BYTE: close code MSB
+   - BYTE: close code LSB
+   - PAYLOAD: payload (< 123 bytes)
+
+Server notifies the client that a child has closed, for whatever reason.
+
+### 0x44: RX: LWS_META_CMD_CLOSE_RQ
+   - BYTE: channel id
+   - BYTE: payload length + 0x20
+   - BYTE: close code MSB
+   - BYTE: close code LSB
+   - PAYLOAD: payload (< 123 bytes)
+
+The client requests to close a child connection
+
+### 0x45: TX: LWS_META_CMD_WRITE
+
+   - BYTE: channel id
+
+Normal write of payload n from lws-meta perspective is actually
+LWS_META_CMD_WRITE, channel id, then (n - 2) bytes of payload
+
+The command only appears at the start of a message, continuations do
+not have the command.
+
+## Protocol Notes
+
+ - Once the subchannel is up, overhead is only +2 bytes per message
+
+ - Close reasons are supported in both directions
+
+ - Ping and Pong are only supported at the lws-meta level, using normal ws ping and pong packets.
+
+ - Only the final close of the tcp lws-meta connection itself goes out as
+   a normal ws close frame.  Subchannels close is done in a normal TEXT
+   message using LWS_META_CMD_CLOSE_RQ and then the close packet payload.
+   This is so intermediaries do not mistake subchannel closures for the
+   tcp / ws link going down.
+
+   Messages that start with LWS_META_CMD_OPEN_SUBCHANNEL only contain those
+   commands but may contain any number of them for the whole duration of the
+   message.  The lws-meta js support collects child open requests made before
+   the parent lws-meta connection is open, and dumps them all in a single
+   message when it does open.
+
+   Messages that start with LWS_META_CMD_OPEN_RESULT or LWS_META_CMD_CLOSE_NOTIFY
+   only contain those two commands, but they may contain any number of them
+   for the whole duration of the message.
+
+
+# Current Implemention Limitations
+
+ - only server side is supported in lws.  The client side JS for
+   a browser is supported.
+
+ - max number of child connections per parent at the moment is 8
+
+ - child connection URL paramter when opening the connection is
+   ignored
+
+ - there is no ah attached when the child connections are
+   established inside the lws-meta parent.  So header access
+   functions will fail.

lib/libwebsockets.c

@@ -116,6 +116,13 @@ lws_set_timeout(struct lws *wsi, enum pending_timeout reason, int secs)
 	struct lws_context_per_thread *pt = &wsi->context->pt[(int)wsi->tsi];
 	time_t now;
 
+	if (secs == LWS_TO_KILL_SYNC) {
+		lws_remove_from_timeout_list(wsi);
+		lwsl_debug("synchronously killing %p\n", wsi);
+		lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS);
+		return;
+	}
+
 	lws_pt_lock(pt);
 
 	time(&now);
@@ -157,6 +164,12 @@ lws_remove_child_from_any_parent(struct lws *wsi)
 		if (*pwsi == wsi) {
 			lwsl_info("%s: detach %p from parent %p\n",
 					__func__, wsi, wsi->parent);
+
+			if (wsi->parent->protocol)
+				wsi->parent->protocol->callback(wsi,
+						LWS_CALLBACK_CHILD_CLOSING,
+					       wsi->parent->user_space, wsi, 0);
+
 			*pwsi = wsi->sibling_list;
 			seen = 1;
 			break;
@@ -228,6 +241,8 @@ lws_close_free_wsi(struct lws *wsi, enum lws_close_status reason)
 	struct lws_tokens eff_buf;
 	int n, m, ret;
 
+	lwsl_debug("%s: %p\n", __func__, wsi);
+
 	if (!wsi)
 		return;
 
@@ -568,6 +583,8 @@ just_kill_connection:
 	/* checking return redundant since we anyway close */
 	if (wsi->desc.sockfd != LWS_SOCK_INVALID)
 		remove_wsi_socket_from_fds(wsi);
+	else
+		lws_same_vh_protocol_remove(wsi);
 
 #if defined(LWS_WITH_ESP8266)
 	espconn_disconnect(wsi->desc.sockfd);
@@ -670,17 +687,18 @@ async_close:
 	wsi->socket_is_permanently_unusable = 1;
 
 #ifdef LWS_USE_LIBUV
-	if (LWS_LIBUV_ENABLED(context)) {
-		if (wsi->listener) {
-			lwsl_debug("%s: stopping listner libuv poll\n", __func__);
-			uv_poll_stop(&wsi->w_read.uv_watcher);
-		}
-		lwsl_debug("%s: lws_libuv_closehandle: wsi %p\n", __func__, wsi);
-		/* libuv has to do his own close handle processing asynchronously */
-		lws_libuv_closehandle(wsi);
+	if (!wsi->parent_carries_io)
+		if (LWS_LIBUV_ENABLED(context)) {
+			if (wsi->listener) {
+				lwsl_debug("%s: stopping listner libuv poll\n", __func__);
+				uv_poll_stop(&wsi->w_read.uv_watcher);
+			}
+			lwsl_debug("%s: lws_libuv_closehandle: wsi %p\n", __func__, wsi);
+			/* libuv has to do his own close handle processing asynchronously */
+			lws_libuv_closehandle(wsi);
 
-		return;
-	}
+			return;
+		}
 #endif
 
 	lws_close_free_wsi_final(wsi);
@@ -856,6 +874,9 @@ lws_get_peer_simple(struct lws *wsi, char *name, int namelen)
 	int af = AF_INET;
 	void *p, *q;
 
+	if (wsi->parent_carries_io)
+		wsi = wsi->parent;
+
 #ifdef LWS_USE_IPV6
 	if (LWS_IPV6_ENABLED(wsi->vhost)) {
 		len = sizeof(sin6);
@@ -1407,6 +1428,12 @@ lws_is_final_fragment(struct lws *wsi)
 	return wsi->u.ws.final && !wsi->u.ws.rx_packet_length && !wsi->u.ws.rx_draining_ext;
 }
 
+LWS_VISIBLE int
+lws_is_first_fragment(struct lws *wsi)
+{
+	return wsi->u.ws.first_fragment;
+}
+
 LWS_VISIBLE unsigned char
 lws_get_reserved_bits(struct lws *wsi)
 {
@@ -1650,6 +1677,48 @@ lws_get_child(const struct lws *wsi)
 	return wsi->child_list;
 }
 
+LWS_VISIBLE LWS_EXTERN void
+lws_set_parent_carries_io(struct lws *wsi)
+{
+	wsi->parent_carries_io = 1;
+}
+
+LWS_VISIBLE LWS_EXTERN void *
+lws_get_opaque_parent_data(const struct lws *wsi)
+{
+	return wsi->opaque_parent_data;
+}
+
+LWS_VISIBLE LWS_EXTERN void
+lws_set_opaque_parent_data(struct lws *wsi, void *data)
+{
+	wsi->opaque_parent_data = data;
+}
+
+LWS_VISIBLE LWS_EXTERN int
+lws_get_child_pending_on_writable(const struct lws *wsi)
+{
+	return wsi->parent_pending_cb_on_writable;
+}
+
+LWS_VISIBLE LWS_EXTERN void
+lws_clear_child_pending_on_writable(struct lws *wsi)
+{
+	wsi->parent_pending_cb_on_writable = 0;
+}
+
+LWS_VISIBLE LWS_EXTERN int
+lws_get_close_length(struct lws *wsi)
+{
+	return wsi->u.ws.close_in_ping_buffer_len;
+}
+
+LWS_VISIBLE LWS_EXTERN unsigned char *
+lws_get_close_payload(struct lws *wsi)
+{
+	return &wsi->u.ws.ping_payload_buf[LWS_PRE];
+}
+
 LWS_VISIBLE LWS_EXTERN void
 lws_close_reason(struct lws *wsi, enum lws_close_status status,
 		 unsigned char *buf, size_t len)

lib/libwebsockets.h

@@ -823,6 +823,38 @@ struct lws_context;
 /* needed even with extensions disabled for create context */
 struct lws_extension;
 
+/*! \defgroup lwsmeta lws-meta
+ *
+ * ##lws-meta protocol
+ *
+ * The protocol wraps other muxed connections inside one tcp connection.
+ *
+ * Commands are assigned from 0x41 up (so they are valid unicode)
+ */
+///@{
+
+enum lws_meta_commands {
+	LWS_META_CMD_OPEN_SUBCHANNEL = 'A',
+	/**< Client requests to open new subchannel
+	 */
+	LWS_META_CMD_OPEN_RESULT,
+	/**< Result of client request to open new subchannel */
+	LWS_META_CMD_CLOSE_NOTIFY,
+	/**< Notification of subchannel closure */
+	LWS_META_CMD_CLOSE_RQ,
+	/**< client requests to close a subchannel */
+	LWS_META_CMD_WRITE,
+	/**< connection writes something to specific channel index */
+
+	/****** add new things just above ---^ ******/
+};
+
+/* channel numbers are transported offset by 0x20 so they are valid unicode */
+
+#define LWS_META_CHANNEL_OFFSET_TRANSPORT 0x20
+
+///@}
+
 /*! \defgroup usercb User Callback
  *
  * ##User protocol callback
@@ -1252,6 +1284,16 @@ enum lws_callback_reasons {
 	 * using the vhost.  @in is a pointer to a
 	 * struct lws_ssl_info containing information about the
 	 * event*/
+	LWS_CALLBACK_CHILD_WRITE_VIA_PARENT			= 68,
+	/**< Child has been marked with parent_carries_io attribute, so
+	 * lws_write directs the to this callback at the parent,
+	 * @in is a struct lws_write_passthru containing the args
+	 * the lws_write() was called with.
+	 */
+	LWS_CALLBACK_CHILD_CLOSING				= 69,
+	/**< Sent to parent to notify them a child is closing / being
+	 * destroyed.  @in is the child wsi.
+	 */
 
 	/****** add new things just above ---^ ******/
 
@@ -2783,6 +2825,9 @@ lws_service_adjust_timeout(struct lws_context *context, int timeout_ms, int tsi)
 /* Backwards compatibility */
 #define lws_plat_service_tsi lws_service_tsi
 
+LWS_VISIBLE LWS_EXTERN int
+lws_handle_POLLOUT_event(struct lws *wsi, struct lws_pollfd *pollfd);
+
 ///@}
 
 /*! \defgroup http HTTP
@@ -3625,6 +3670,19 @@ enum pending_timeout {
 	/****** add new things just above ---^ ******/
 };
 
+#define LWS_TO_KILL_ASYNC -1
+/**< If LWS_TO_KILL_ASYNC is given as the timeout sec in a lws_set_timeout()
+ * call, then the connection is marked to be killed at the next timeout
+ * check.  This is how you should force-close the wsi being serviced if
+ * you are doing it outside the callback (where you should close by nonzero
+ * return).
+ */
+#define LWS_TO_KILL_SYNC -2
+/**< If LWS_TO_KILL_SYNC is given as the timeout sec in a lws_set_timeout()
+ * call, then the connection is closed before returning (which may delete
+ * the wsi).  This should only be used where the wsi being closed is not the
+ * wsi currently being serviced.
+ */
 /**
  * lws_set_timeout() - marks the wsi as subject to a timeout
  *
@@ -3632,7 +3690,10 @@ enum pending_timeout {
  *
  * \param wsi:	Websocket connection instance
  * \param reason:	timeout reason
- * \param secs:	how many seconds
+ * \param secs:	how many seconds.  You may set to LWS_TO_KILL_ASYNC to
+ *		force the connection to timeout at the next opportunity, or
+ *		LWS_TO_KILL_SYNC to close it synchronously if you know the
+ *		wsi is not the one currently being serviced.
  */
 LWS_VISIBLE LWS_EXTERN void
 lws_set_timeout(struct lws *wsi, enum pending_timeout reason, int secs);
@@ -3657,7 +3718,8 @@ lws_set_timeout(struct lws *wsi, enum pending_timeout reason, int secs);
 #endif
 #define _LWS_PAD(n) (((n) % _LWS_PAD_SIZE) ? \
 		((n) + (_LWS_PAD_SIZE - ((n) % _LWS_PAD_SIZE))) : (n))
-#define LWS_PRE _LWS_PAD(4 + 10)
+/* last 2 is for lws-meta */
+#define LWS_PRE _LWS_PAD(4 + 10 + 2)
 /* used prior to 1.7 and retained for backward compatibility */
 #define LWS_SEND_BUFFER_PRE_PADDING LWS_PRE
 #define LWS_SEND_BUFFER_POST_PADDING 0
@@ -3709,6 +3771,15 @@ enum lws_write_protocol {
 	 * decode the content if used */
 };
 
+/* used with LWS_CALLBACK_CHILD_WRITE_VIA_PARENT */
+
+struct lws_write_passthru {
+	struct lws *wsi;
+	unsigned char *buf;
+	size_t len;
+	enum lws_write_protocol wp;
+};
+
 
 /**
  * lws_write() - Apply protocol then write data to client
@@ -4053,7 +4124,11 @@ typedef enum {
 	LWS_ADOPT_RAW_FILE_DESC = 0,	/* convenience constant */
 	LWS_ADOPT_HTTP = 1,		/* flag: absent implies RAW */
 	LWS_ADOPT_SOCKET = 2,		/* flag: absent implies file descr */
-	LWS_ADOPT_ALLOW_SSL = 4		/* flag: if set requires LWS_ADOPT_SOCKET */
+	LWS_ADOPT_ALLOW_SSL = 4,	/* flag: if set requires LWS_ADOPT_SOCKET */
+	LWS_ADOPT_WS_PARENTIO = 8,	/* flag: ws mode parent handles IO
+					 *   if given must be only flag
+					 *   wsi put directly into ws mode
+					 */
 } lws_adoption_type;
 
 typedef union {
@@ -4411,6 +4486,32 @@ lws_get_parent(const struct lws *wsi);
 LWS_VISIBLE LWS_EXTERN struct lws * LWS_WARN_UNUSED_RESULT
 lws_get_child(const struct lws *wsi);
 
+/**
+ * lws_parent_carries_io() - mark wsi as needing to send messages via parent
+ *
+ * \param wsi: child lws connection
+ */
+
+LWS_VISIBLE LWS_EXTERN void
+lws_set_parent_carries_io(struct lws *wsi);
+
+LWS_VISIBLE LWS_EXTERN void *
+lws_get_opaque_parent_data(const struct lws *wsi);
+
+LWS_VISIBLE LWS_EXTERN void
+lws_set_opaque_parent_data(struct lws *wsi, void *data);
+
+LWS_VISIBLE LWS_EXTERN int
+lws_get_child_pending_on_writable(const struct lws *wsi);
+
+LWS_VISIBLE LWS_EXTERN void
+lws_clear_child_pending_on_writable(struct lws *wsi);
+
+LWS_VISIBLE LWS_EXTERN int
+lws_get_close_length(struct lws *wsi);
+
+LWS_VISIBLE LWS_EXTERN unsigned char *
+lws_get_close_payload(struct lws *wsi);
 
 /*
  * \deprecated DEPRECATED Note: this is not normally needed as a user api.
@@ -4448,11 +4549,20 @@ lws_send_pipe_choked(struct lws *wsi);
 
 /**
  * lws_is_final_fragment() - tests if last part of ws message
+ *
  * \param wsi: lws connection
  */
 LWS_VISIBLE LWS_EXTERN int
 lws_is_final_fragment(struct lws *wsi);
 
+/**
+ * lws_is_first_fragment() - tests if first part of ws message
+ *
+ * \param wsi: lws connection
+ */
+LWS_VISIBLE LWS_EXTERN int
+lws_is_first_fragment(struct lws *wsi);
+
 /**
  * lws_get_reserved_bits() - access reserved bits of ws frame
  * \param wsi: lws connection

lib/output.c

@@ -250,6 +250,23 @@ LWS_VISIBLE int lws_write(struct lws *wsi, unsigned char *buf, size_t len,
 	int pre = 0, n;
 	size_t orig_len = len;
 
+	if (wsi->parent_carries_io) {
+		struct lws_write_passthru pas;
+
+		pas.buf = buf;
+		pas.len = len;
+		pas.wp = wp;
+		pas.wsi = wsi;
+
+		if (wsi->parent->protocol->callback(wsi->parent,
+				LWS_CALLBACK_CHILD_WRITE_VIA_PARENT,
+				wsi->parent->user_space,
+				(void *)&pas, 0))
+			return 1;
+
+		return len;
+	}
+
 	lws_stats_atomic_bump(wsi->context, pt, LWSSTATS_C_API_LWS_WRITE, 1);
 
 	if ((int)len < 0) {

lib/parsers.c

@@ -385,6 +385,9 @@ lws_hdr_fragment_length(struct lws *wsi, enum lws_token_indexes h, int frag_idx)
 {
 	int n;
 
+	if (!wsi->u.hdr.ah)
+		return 0;
+
 	n = wsi->u.hdr.ah->frag_index[h];
 	if (!n)
 		return 0;
@@ -402,6 +405,9 @@ LWS_VISIBLE int lws_hdr_total_length(struct lws *wsi, enum lws_token_indexes h)
 	int n;
 	int len = 0;
 
+	if (!wsi->u.hdr.ah)
+		return 0;
+
 	n = wsi->u.hdr.ah->frag_index[h];
 	if (!n)
 		return 0;
@@ -417,7 +423,12 @@ LWS_VISIBLE int lws_hdr_copy_fragment(struct lws *wsi, char *dst, int len,
 				      enum lws_token_indexes h, int frag_idx)
 {
 	int n = 0;
-	int f = wsi->u.hdr.ah->frag_index[h];
+	int f;
+
+	if (!wsi->u.hdr.ah)
+		return -1;
+
+	f = wsi->u.hdr.ah->frag_index[h];
 
 	if (!f)
 		return -1;
@@ -448,6 +459,9 @@ LWS_VISIBLE int lws_hdr_copy(struct lws *wsi, char *dst, int len,
 	if (toklen >= len)
 		return -1;
 
+	if (!wsi->u.hdr.ah)
+		return -1;
+
 	n = wsi->u.hdr.ah->frag_index[h];
 	if (!n)
 		return 0;
@@ -1145,6 +1159,7 @@ handle_first:
 			wsi->u.ws.rsv_first_msg = (c & 0x70);
 			wsi->u.ws.frame_is_binary =
 			     wsi->u.ws.opcode == LWSWSOPC_BINARY_FRAME;
+			wsi->u.ws.first_fragment = 1;
 			break;
 		case 3:
 		case 4:
@@ -1492,6 +1507,7 @@ drain_extension:
 		/* eff_buf may be pointing somewhere completely different now,
 		 * it's the output
 		 */
+		wsi->u.ws.first_fragment = 0;
 		if (n < 0) {
 			/*
 			 * we may rely on this to get RX, just drop connection

lib/pollfd.c

@@ -236,6 +236,11 @@ remove_wsi_socket_from_fds(struct lws *wsi)
 #endif
 	int m, ret = 0;
 
+	if (wsi->parent_carries_io) {
+		lws_same_vh_protocol_remove(wsi);
+		return 0;
+	}
+
 #if !defined(_WIN32) && !defined(LWS_WITH_ESP8266)
 	if (wsi->desc.sockfd > context->max_fds) {
 		lwsl_err("fd %d too high (%d)\n", wsi->desc.sockfd, context->max_fds);
@@ -348,6 +353,16 @@ lws_callback_on_writable(struct lws *wsi)
 	if (wsi->socket_is_permanently_unusable)
 		return 0;
 
+	if (wsi->parent_carries_io) {
+		int n = lws_callback_on_writable(wsi->parent);
+
+		if (n < 0)
+			return n;
+
+		wsi->parent_pending_cb_on_writable = 1;
+		return 1;
+	}
+
 	pt = &wsi->context->pt[(int)wsi->tsi];
 	lws_stats_atomic_bump(wsi->context, pt, LWSSTATS_C_WRITEABLE_CB_REQ, 1);
 #if defined(LWS_WITH_STATS)

lib/private-libwebsockets.h

@@ -1484,6 +1484,7 @@ struct _lws_websocket_related {
 	unsigned int rx_draining_ext:1;
 	unsigned int tx_draining_ext:1;
 	unsigned int send_check_ping:1;
+	unsigned int first_fragment:1;
 };
 
 #ifdef LWS_WITH_CGI
@@ -1588,6 +1589,7 @@ struct lws {
 	struct lws_access_log access_log;
 #endif
 	void *user_space;
+	void *opaque_parent_data;
 	/* rxflow handling */
 	unsigned char *rxflow_buffer;
 	/* truncated send handling */
@@ -1651,6 +1653,8 @@ struct lws {
 	unsigned int told_user_closed:1;
 	unsigned int waiting_to_send_close_frame:1;
 	unsigned int ipv6:1;
+	unsigned int parent_carries_io:1;
+	unsigned int parent_pending_cb_on_writable:1;
 
 #if defined(LWS_WITH_ESP8266)
 	unsigned int pending_send_completion:3;

lib/server.c

@@ -1284,6 +1284,57 @@ transaction_result_n:
 #endif
 }
 
+static int
+lws_server_init_wsi_for_ws(struct lws *wsi)
+{
+	int n;
+
+	wsi->state = LWSS_ESTABLISHED;
+	lws_restart_ws_ping_pong_timer(wsi);
+
+	/*
+	 * create the frame buffer for this connection according to the
+	 * size mentioned in the protocol definition.  If 0 there, use
+	 * a big default for compatibility
+	 */
+
+	n = wsi->protocol->rx_buffer_size;
+	if (!n)
+		n = wsi->context->pt_serv_buf_size;
+	n += LWS_PRE;
+	wsi->u.ws.rx_ubuf = lws_malloc(n + 4 /* 0x0000ffff zlib */);
+	if (!wsi->u.ws.rx_ubuf) {
+		lwsl_err("Out of Mem allocating rx buffer %d\n", n);
+		return 1;
+	}
+	wsi->u.ws.rx_ubuf_alloc = n;
+	lwsl_debug("Allocating RX buffer %d\n", n);
+
+#if LWS_POSIX && !defined(LWS_WITH_ESP32)
+	if (!wsi->parent_carries_io)
+		if (setsockopt(wsi->desc.sockfd, SOL_SOCKET, SO_SNDBUF,
+		       (const char *)&n, sizeof n)) {
+			lwsl_warn("Failed to set SNDBUF to %d", n);
+			return 1;
+		}
+#endif
+
+	/* notify user code that we're ready to roll */
+
+	if (wsi->protocol->callback)
+		if (wsi->protocol->callback(wsi, LWS_CALLBACK_ESTABLISHED,
+					    wsi->user_space,
+#ifdef LWS_OPENSSL_SUPPORT
+					    wsi->ssl,
+#else
+					    NULL,
+#endif
+					    0))
+			return 1;
+
+	return 0;
+}
+
 int
 lws_handshake_server(struct lws *wsi, unsigned char **buf, size_t len)
 {
@@ -1652,49 +1703,10 @@ upgrade_ws:
 		wsi->u.hdr = hdr;
 		lws_pt_unlock(pt);
 
-		lws_restart_ws_ping_pong_timer(wsi);
-
-		/*
-		 * create the frame buffer for this connection according to the
-		 * size mentioned in the protocol definition.  If 0 there, use
-		 * a big default for compatibility
-		 */
-
-		n = wsi->protocol->rx_buffer_size;
-		if (!n)
-			n = context->pt_serv_buf_size;
-		n += LWS_PRE;
-		wsi->u.ws.rx_ubuf = lws_malloc(n + 4 /* 0x0000ffff zlib */);
-		if (!wsi->u.ws.rx_ubuf) {
-			lwsl_err("Out of Mem allocating rx buffer %d\n", n);
-			return 1;
-		}
-		wsi->u.ws.rx_ubuf_alloc = n;
-		lwsl_debug("Allocating RX buffer %d\n", n);
-#if LWS_POSIX && !defined(LWS_WITH_ESP32)
-		if (setsockopt(wsi->desc.sockfd, SOL_SOCKET, SO_SNDBUF,
-			       (const char *)&n, sizeof n)) {
-			lwsl_warn("Failed to set SNDBUF to %d", n);
-			return 1;
-		}
-#endif
-
+		lws_server_init_wsi_for_ws(wsi);
 		lwsl_parser("accepted v%02d connection\n",
 			    wsi->ietf_spec_revision);
 
-		/* notify user code that we're ready to roll */
-
-		if (wsi->protocol->callback)
-			if (wsi->protocol->callback(wsi, LWS_CALLBACK_ESTABLISHED,
-						    wsi->user_space,
-#ifdef LWS_OPENSSL_SUPPORT
-						    wsi->ssl,
-#else
-						    NULL,
-#endif
-						    0))
-				return 1;
-
 		/* !!! drop ah unreservedly after ESTABLISHED */
 		if (!wsi->more_rx_waiting) {
 			lws_header_table_force_to_detachable_state(wsi);
@@ -1782,6 +1794,8 @@ lws_create_new_server_wsi(struct lws_vhost *vhost)
 	new_wsi->user_space = NULL;
 	new_wsi->ietf_spec_revision = 0;
 	new_wsi->desc.sockfd = LWS_SOCK_INVALID;
+	new_wsi->position_in_fds_table = -1;
+
 	vhost->context->count_wsi_allocated++;
 
 	/*
@@ -1889,7 +1903,7 @@ lws_adopt_descriptor_vhost(struct lws_vhost *vh, lws_adoption_type type,
 	int n, ssl = 0;
 
 	if (!new_wsi) {
-		if (type & LWS_ADOPT_SOCKET)
+		if (type & LWS_ADOPT_SOCKET && !(type & LWS_ADOPT_WS_PARENTIO))
 			compatible_close(fd.sockfd);
 		return NULL;
 	}
@@ -1900,6 +1914,9 @@ lws_adopt_descriptor_vhost(struct lws_vhost *vh, lws_adoption_type type,
 		new_wsi->parent = parent;
 		new_wsi->sibling_list = parent->child_list;
 		parent->child_list = new_wsi;
+
+		if (type & LWS_ADOPT_WS_PARENTIO)
+			new_wsi->parent_carries_io = 1;
 	}
 
 	new_wsi->desc = fd;
@@ -1916,6 +1933,15 @@ lws_adopt_descriptor_vhost(struct lws_vhost *vh, lws_adoption_type type,
                        lwsl_notice("OOM trying to get user_space\n");
 			goto bail;
                }
+               if (type & LWS_ADOPT_WS_PARENTIO) {
+			new_wsi->desc.sockfd = LWS_SOCK_INVALID;
+			lwsl_debug("binding to %s\n", new_wsi->protocol->name);
+			lws_bind_protocol(new_wsi, new_wsi->protocol);
+			lws_union_transition(new_wsi, LWSCM_WS_SERVING);
+			lws_server_init_wsi_for_ws(new_wsi);
+
+			return new_wsi;
+               }
 	} else
 		if (type & LWS_ADOPT_HTTP) /* he will transition later */
 			new_wsi->protocol =

lib/service.c

@@ -329,6 +329,13 @@ lws_handle_POLLOUT_event(struct lws *wsi, struct lws_pollfd *pollfd)
 user_service:
 	/* one shot */
 
+	if (wsi->parent_carries_io) {
+		wsi->handling_pollout = 0;
+		wsi->leave_pollout_active = 0;
+
+		return lws_calllback_as_writeable(wsi);
+	}
+
 	if (pollfd) {
 		int eff = wsi->leave_pollout_active;
 

lwsws/etc-lwsws-conf.d-localhost-EXAMPLE

@@ -32,6 +32,9 @@
      # vhost-specific config options for the protocol
      #
      "ws-protocols": [{
+       "lws-meta": {
+         "status": "ok"
+       },
        "dumb-increment-protocol": {
          "status": "ok"
        },

plugins/protocol_lws_meta.c

@@ -0,0 +1,613 @@
+/*
+ * lws meta protocol handler
+ *
+ * Copyright (C) 2017 Andy Green <andy@warmcat.com>
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation:
+ *  version 2.1 of the License.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ *  MA  02110-1301  USA*
+ *
+ */
+
+#if !defined (LWS_PLUGIN_STATIC)
+#define LWS_DLL
+#define LWS_INTERNAL
+#include "../lib/libwebsockets.h"
+#endif
+
+#include <string.h>
+#include <stdlib.h>
+
+#define MAX_SUBCHANNELS 8
+
+enum lws_meta_parser_state {
+	MP_IDLE, /* in body of message */
+
+	MP_CMD, /* await cmd */
+
+	MP_OPEN_SUBCHANNEL_PROTOCOL,
+	MP_OPEN_SUBCHANNEL_URL,
+	MP_OPEN_SUBCHANNEL_COOKIE,
+
+	MP_CLOSE_CHID,
+	MP_CLOSE_LEN,
+	MP_CLOSE_CODEM,
+	MP_CLOSE_CODEL,
+	MP_CLOSE_PAYLOAD,
+
+	MP_WRITE_CHID,
+};
+
+enum {
+	PENDING_TYPE_OPEN_RESULT = 0,
+	PENDING_TYPE_CHILD_CLOSE
+};
+
+/*
+ * while we haven't reported the result yet, we keep a linked-list of
+ * connection opens and their result.
+ */
+
+struct pending_conn {
+	struct pending_conn *next;
+	char protocol[123];
+	char cookie[8];
+	int ch;
+	int len;
+
+	unsigned char type;
+};
+
+/* the parent, lws-meta connection */
+
+struct per_session_data__lws_meta {
+	struct lws *wsi[MAX_SUBCHANNELS + 1];
+	char told_closing[MAX_SUBCHANNELS + 1];
+	struct pending_conn *first;
+	struct pending_conn *pend;
+	char suburl[64];
+	unsigned char close[126];
+	int active_subchannel_tx, active_subchannel_rx;
+	enum lws_meta_parser_state state;
+	int pos;
+	int count_pending;
+	int round_robin;
+	int close_status_16;
+	int close_len;
+	int which_close;
+	int ch;
+};
+
+static int
+lws_find_free_channel(struct per_session_data__lws_meta *pss)
+{
+	int n;
+
+	for (n = 1; n <= MAX_SUBCHANNELS; n++)
+		if (pss->wsi[n] == NULL)
+			return n;
+
+	return 0; /* none free */
+}
+
+static struct lws *
+lws_get_channel_wsi(struct per_session_data__lws_meta *pss, int ch)
+{
+	if (!ch)
+		return 0;
+	return pss->wsi[ch];
+}
+
+static int
+lws_get_channel_id(struct lws *wsi)
+{
+	return (lws_intptr_t)lws_get_opaque_parent_data(wsi);
+}
+
+static void
+lws_set_channel_id(struct lws *wsi, int id)
+{
+	lws_set_opaque_parent_data(wsi, (void *)(lws_intptr_t)id);
+}
+
+static struct pending_conn *
+new_pending(struct per_session_data__lws_meta *pss)
+{
+	struct pending_conn *pend;
+
+	if (pss->count_pending >= MAX_SUBCHANNELS * 2) {
+		lwsl_notice("too many pending open subchannel\n");
+		return NULL;
+	}
+
+	pss->count_pending++;
+
+	pend = malloc(sizeof(*pend));
+	if (!pend) {
+		lwsl_notice("OOM\n");
+		return NULL;
+	}
+
+	memset(pend, 0, sizeof(*pend));
+
+	return pend;
+}
+
+
+static int
+callback_lws_meta(struct lws *wsi, enum lws_callback_reasons reason,
+		    void *user, void *in, size_t len)
+{
+	struct per_session_data__lws_meta *pss =
+			(struct per_session_data__lws_meta *)user;
+	struct lws_write_passthru *pas;
+	struct pending_conn *pend, *pend1;
+	struct lws *cwsi;
+	lws_sock_file_fd_type fd;
+	unsigned char *bin, buf[LWS_PRE + 512], *start = &buf[LWS_PRE],
+			*end = &buf[sizeof(buf) - 1], *p = start;
+	int n, m;
+
+	switch (reason) {
+
+	case LWS_CALLBACK_ESTABLISHED:
+		lwsl_info("%s: LWS_CALLBACK_ESTABLISHED\n", __func__);
+		pss->state = MP_CMD;
+		pss->pos = 0;
+		break;
+
+	case LWS_CALLBACK_CLOSED:
+		break;
+
+	case LWS_CALLBACK_CHILD_CLOSING:
+		cwsi = (struct lws *)in;
+
+		/* remove it from our tracking */
+		pss->wsi[lws_get_channel_id(cwsi)] = NULL;
+
+		if (pss->told_closing[lws_get_channel_id(cwsi)]) {
+			pss->told_closing[lws_get_channel_id(cwsi)] = 0;
+			break;
+		}
+
+		pend = new_pending(pss);
+		if (!pend)
+			return -1;
+
+		/* note which channel id */
+		pend->ch = lws_get_channel_id(cwsi);
+
+
+		if (lws_get_close_length(cwsi)) {
+			pend->len = lws_get_close_length(cwsi);
+			memcpy(pend->protocol, lws_get_close_payload(cwsi),
+					pend->len);
+		}
+
+		pend->type = PENDING_TYPE_CHILD_CLOSE;
+		pend->next = pss->first;
+		pss->first = pend;
+
+		/*
+		 * nothing else will complete from this wsi, so abandon
+		 * tracking in-process messages from this wsi.
+		 */
+
+		if (pss->active_subchannel_tx == pend->ch)
+			pss->active_subchannel_tx = 0;
+
+		if (pss->active_subchannel_rx == pend->ch)
+			pss->active_subchannel_rx = 0;
+		break;
+
+	case LWS_CALLBACK_SERVER_WRITEABLE:
+
+		if (!pss->active_subchannel_tx) {
+
+			/* not in the middle of a message...
+			 *
+			 * PRIORITY 1: pending open and close notifications
+			 */
+
+			pend = pss->first;
+			while (pend && p < end - 128) {
+				switch (pend->type) {
+				case PENDING_TYPE_OPEN_RESULT:
+					lwsl_debug("open result %s %s\n", pend->cookie, pend->protocol);
+					*p++ = LWS_META_CMD_OPEN_RESULT;
+					memcpy(p, pend->cookie,
+					       strlen(pend->cookie) + 1);
+					p += strlen(pend->cookie) + 1;
+					*p++ = LWS_META_CHANNEL_OFFSET_TRANSPORT + pend->ch;
+					memcpy(p, pend->protocol,
+					       strlen(pend->protocol) + 1);
+					p += strlen(pend->protocol) + 1;
+					break;
+				case PENDING_TYPE_CHILD_CLOSE:
+					*p++ = LWS_META_CMD_CLOSE_NOTIFY;
+					*p++ = LWS_META_CHANNEL_OFFSET_TRANSPORT + pend->ch;
+					for (n = 0; n < pend->len; n++)
+						*p++ = pend->protocol[n];
+					break;
+				}
+
+				pss->count_pending--;
+				pend1 = pend;
+				pend = pend->next;
+				free(pend1);
+				pss->first = pend;
+			}
+
+			if (p != start) {
+				if (lws_write(wsi, start, p - start, LWS_WRITE_BINARY) < 0)
+					return 1;
+				if (pend) /* still more */
+					lws_callback_on_writable(wsi);
+				break;
+			}
+
+			/* PRIORITY 2: pick a child to get the writable callback */
+
+			cwsi = NULL;
+			for (n = 0; n < MAX_SUBCHANNELS; n++) {
+				m = ((pss->round_robin + n) % MAX_SUBCHANNELS) + 1;
+				if (pss->wsi[m] &&
+				    lws_get_child_pending_on_writable(pss->wsi[m])) {
+					pss->round_robin = m;
+					cwsi = pss->wsi[m];
+					break;
+				}
+			}
+
+		} else
+			/* one child is in middle of message, stay with it */
+			cwsi = pss->wsi[pss->active_subchannel_tx];
+
+		if (!cwsi)
+			break;
+
+		lws_clear_child_pending_on_writable(cwsi);
+		if (lws_handle_POLLOUT_event(cwsi, NULL))
+			return -1;
+		break;
+
+	case LWS_CALLBACK_RECEIVE:
+		bin = (unsigned char *)in;
+
+		/*
+		 * at the start of a message, we may have one or more
+		 * lws_meta command blocks.
+		 */
+
+		while (pss->state != MP_IDLE &&
+		       (unsigned int)(bin - (unsigned char *)in) < len) {
+
+			switch (pss->state) {
+			case MP_IDLE: /* in body of message */
+
+				if (!lws_is_first_fragment(wsi))
+					break;
+
+				pss->state = MP_CMD;
+
+				/* fallthru */
+
+			case MP_CMD: /* await cmd */
+
+				pss->pos = 0;
+
+				switch (*bin++) {
+				case LWS_META_CMD_OPEN_SUBCHANNEL:
+
+					pss->pend = new_pending(pss);
+					if (!pss->pend)
+						return -1;
+
+					pss->state = MP_OPEN_SUBCHANNEL_PROTOCOL;
+
+					break;
+				case LWS_META_CMD_CLOSE_NOTIFY:
+				case LWS_META_CMD_CLOSE_RQ:
+					pss->which_close = bin[-1];
+					pss->state = MP_CLOSE_CHID;
+					break;
+				case LWS_META_CMD_WRITE:
+					pss->state = MP_WRITE_CHID;
+					break;
+
+				// open result is also illegal to receive
+				default:
+					lwsl_notice("illegal lws_meta cmd 0x%x\n", bin[-1]);
+
+					return -1;
+				}
+
+				break;
+
+			case MP_OPEN_SUBCHANNEL_PROTOCOL:
+				pss->pend->protocol[pss->pos++] = *bin++;
+				if (pss->pos == sizeof(pss->pend->protocol) - 1) {
+					lwsl_notice("protocol name too long\n");
+					return -1;
+				}
+
+				if (bin[-1] != '\0')
+					break;
+
+				pss->state = MP_OPEN_SUBCHANNEL_URL;
+				pss->pos = 0;
+				break;
+
+			case MP_OPEN_SUBCHANNEL_URL:
+				pss->suburl[pss->pos++] = *bin++;
+				if (pss->pos == sizeof(pss->suburl) - 1) {
+					lwsl_notice("suburl too long\n");
+					return -1;
+				}
+
+				if (bin[-1] != '\0')
+					break;
+
+				pss->state = MP_OPEN_SUBCHANNEL_COOKIE;
+				pss->pos = 0;
+				break;
+
+			case MP_OPEN_SUBCHANNEL_COOKIE:
+				pss->pend->cookie[pss->pos++] = *bin++;
+				if (pss->pos == sizeof(pss->pend->cookie) - 1) {
+					lwsl_notice("cookie too long\n");
+					return -1;
+				}
+
+				if (bin[-1] != '\0')
+					break;
+
+				lwsl_debug("%s: %s / %s / %s\n", __func__,
+					    pss->pend->protocol,
+					    pss->suburl,
+					    pss->pend->cookie);
+
+				pss->pend->ch = lws_find_free_channel(pss);
+				if (pss->pend->ch) {
+
+					fd.sockfd = 0; // not going to be used
+
+					cwsi = lws_adopt_descriptor_vhost(
+							lws_get_vhost(wsi),
+							LWS_ADOPT_WS_PARENTIO,
+							fd, pss->pend->protocol,
+							wsi);
+
+					if (!cwsi) {
+						lwsl_notice("open failed\n");
+						pss->pend->ch = 0;
+					} else {
+						pss->wsi[pss->pend->ch] = cwsi;
+						lws_set_channel_id(cwsi,
+								pss->pend->ch);
+						lwsl_debug("cwsi %p on parent %p open OK %s\n",
+							cwsi, wsi, pss->pend->protocol);
+					}
+
+				} else
+					lwsl_notice("no free subchannels\n");
+
+				pss->pend->type = PENDING_TYPE_OPEN_RESULT;
+				pss->pend->next = pss->first;
+				pss->first = pss->pend;
+
+				lws_callback_on_writable(wsi);
+
+				pss->state = MP_CMD;
+				pss->pos = 0;
+				break;
+
+			case MP_CLOSE_CHID:
+				pss->ch = (*bin++) - LWS_META_CHANNEL_OFFSET_TRANSPORT;
+				pss->state = MP_CLOSE_LEN;
+				pss->pos = 0;
+				break;
+			case MP_CLOSE_LEN:
+				pss->close_len = (*bin++) - LWS_META_CHANNEL_OFFSET_TRANSPORT;
+				lwsl_debug("close len %d\n", pss->close_len);
+				pss->state = MP_CLOSE_CODEM;
+				pss->pos = 0;
+				break;
+			case MP_CLOSE_CODEM:
+				pss->close[pss->pos++] = *bin;
+				pss->close_status_16 = (*bin++) * 256;
+				pss->state = MP_CLOSE_CODEL;
+				break;
+			case MP_CLOSE_CODEL:
+				pss->close[pss->pos++] = *bin;
+				pss->close_status_16 |= *bin++;
+				pss->state = MP_CLOSE_PAYLOAD;
+				break;
+			case MP_CLOSE_PAYLOAD:
+				pss->close[pss->pos++] = *bin++;
+				if (pss->pos == sizeof(pss->close) - 1) {
+					lwsl_notice("close payload too long\n");
+					return -1;
+				}
+				if (--pss->close_len)
+					break;
+
+				cwsi = lws_get_channel_wsi(pss, pss->ch);
+				if (!cwsi)
+					lwsl_notice("received close (%d) for unknown ch %d\n", pss->which_close, pss->ch);
+				else {
+
+					if (pss->which_close == LWS_META_CMD_CLOSE_RQ) {
+
+						if (lws_get_protocol(cwsi)->callback(cwsi,
+						    LWS_CALLBACK_WS_PEER_INITIATED_CLOSE,
+						    lws_wsi_user(cwsi),
+						    &pss->close, pss->pos))
+							return -1;
+
+						/*
+						 * we need to echo back the close payload
+						 * when we send the close notification
+						 */
+
+						lws_close_reason(cwsi,
+								 pss->close_status_16,
+								 &pss->close[2], pss->pos - 2);
+					}
+
+					/* so force him closed */
+
+					lws_set_timeout(cwsi,
+						PENDING_TIMEOUT_KILLED_BY_PARENT,
+						LWS_TO_KILL_SYNC);
+				}
+
+				pss->state = MP_CMD;
+				break;
+
+			case MP_WRITE_CHID:
+				pss->active_subchannel_rx = (*bin++) -
+					LWS_META_CHANNEL_OFFSET_TRANSPORT;
+				pss->state = MP_IDLE;
+				break;
+			}
+
+		}
+
+		len -= bin - (unsigned char *)in;
+
+		if (!len)
+			break;
+
+		cwsi = lws_get_channel_wsi(pss, pss->active_subchannel_rx);
+		if (!cwsi) {
+			lwsl_notice("invalid ch %d\n", pss->active_subchannel_rx);
+
+			return -1;
+		}
+
+		lwsl_debug("%s: RX len %d\n", __func__, (int)len);
+
+		if (lws_get_protocol(cwsi)->callback(
+				cwsi,
+				LWS_CALLBACK_RECEIVE,
+				lws_wsi_user(cwsi),
+				bin, len)) {
+			lws_set_timeout(cwsi,
+				PENDING_TIMEOUT_KILLED_BY_PARENT,
+				LWS_TO_KILL_SYNC);
+		}
+
+		if (lws_is_final_fragment(wsi)) {
+			pss->active_subchannel_rx = 0;
+			pss->state = MP_CMD;
+		}
+		break;
+
+	/*
+	 * child wrote something via lws_write.... which passed it up to us to
+	 * deal with, because we are the parent.  Prepend two bytes for
+	 * lws-meta command and channel index, and send it out on parent
+	 */
+	case LWS_CALLBACK_CHILD_WRITE_VIA_PARENT:
+		pas = in;
+		bin = ((unsigned char *)pas->buf);
+
+		if ((pas->wp & 7) == 4 /*LWS_WRITE_CLOSE */) {
+			*p++ = LWS_META_CMD_CLOSE_NOTIFY;
+			*p++ = LWS_META_CHANNEL_OFFSET_TRANSPORT +
+					lws_get_channel_id(pas->wsi);
+			*p++ = pas->len - 2 + LWS_META_CHANNEL_OFFSET_TRANSPORT;
+			*p++ = *bin++;
+			*p++ = *bin++;
+			for (n = 0; n < (int)pas->len - 2; n++)
+				*p++ = bin[n];
+
+			if (lws_write(wsi, start, p - start, LWS_WRITE_BINARY) < 0)
+				return 1;
+
+			pss->told_closing[lws_get_channel_id(pas->wsi)] = 1;
+			break;
+		}
+
+		if ((pas->wp & 7) == LWS_WRITE_TEXT ||
+		    (pas->wp & 7) == LWS_WRITE_BINARY) {
+
+			if (pas->wp & LWS_WRITE_NO_FIN)
+				pss->active_subchannel_tx =
+						lws_get_channel_id(pas->wsi);
+
+			/* start of message, prepend the subchannel id */
+
+			bin -= 2;
+			bin[0] = LWS_META_CMD_WRITE;
+			bin[1] = lws_get_channel_id(pas->wsi) +
+					LWS_META_CHANNEL_OFFSET_TRANSPORT;
+			if (lws_write(wsi, bin, pas->len + 2, pas->wp) < 0)
+				return 1;
+
+		} else
+			if (lws_write(wsi, bin, pas->len, pas->wp) < 0)
+				return 1;
+
+		/* track EOM */
+
+		if (!(pas->wp & LWS_WRITE_NO_FIN))
+			pss->active_subchannel_tx = 0;
+		break;
+
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+#define LWS_PLUGIN_PROTOCOL_LWS_META { \
+		"lws-meta", \
+		callback_lws_meta, \
+		sizeof(struct per_session_data__lws_meta), \
+		1024, /* rx buf size must be >= permessage-deflate rx size */ \
+	}
+
+#if !defined (LWS_PLUGIN_STATIC)
+
+static const struct lws_protocols protocols[] = {
+	LWS_PLUGIN_PROTOCOL_LWS_META
+};
+
+LWS_EXTERN LWS_VISIBLE int
+init_protocol_lws_meta(struct lws_context *context,
+			     struct lws_plugin_capability *c)
+{
+	if (c->api_magic != LWS_PLUGIN_API_MAGIC) {
+		lwsl_err("Plugin API %d, library API %d", LWS_PLUGIN_API_MAGIC,
+			 c->api_magic);
+		return 1;
+	}
+
+	c->protocols = protocols;
+	c->count_protocols = ARRAY_SIZE(protocols);
+	c->extensions = NULL;
+	c->count_extensions = 0;
+
+	return 0;
+}
+
+LWS_EXTERN LWS_VISIBLE int
+destroy_protocol_lws_meta(struct lws_context *context)
+{
+	return 0;
+}
+#endif

test-server/lws-common.js

@@ -108,6 +108,285 @@ function removeEvent( obj, type, fn ) {
  * end of grayOut related stuff
  */
  
+/*
+ * lws-meta helpers
+ */
+
+var lws_meta_cmd = {
+	OPEN_SUBCHANNEL: 0x41,
+	/**< Client requests to open new subchannel
+	 */
+	OPEN_RESULT: 0x42,
+	/**< Result of client request to open new subchannel */
+	CLOSE_NOT: 0x43,
+	CLOSE_RQ: 0x44,
+	/**< client requests to close a subchannel */
+	WRITE: 0x45,
+	/**< connection writes something to specific channel index */
+	RX: 0x46,
+};
+
+function new_ws(urlpath, protocol)
+{
+	if (typeof MozWebSocket != "undefined")
+		return new MozWebSocket(urlpath, protocol);
+
+	return new WebSocket(urlpath, protocol);
+}
+
+function lws_meta_ws() {
+	var real;
+	
+	var channel_id_to_child;
+	var pending_children;
+	var active_children;
+}
+
+function lws_meta_ws_child() {
+	var onopen;
+	var onmessage;
+	var onclose;
+	
+	var channel_id;
+	
+	var subprotocol;
+	var suburl;
+	var cookie;
+	
+	var extensions;
+	
+	var parent;
+}
+
+lws_meta_ws_child.prototype.send = function(data)
+{
+
+	if (typeof data == "string") {
+		data = String.fromCharCode(lws_meta_cmd.WRITE) +
+			String.fromCharCode(this.channel_id) +
+			data;
+		
+		return this.parent.real.send(data);
+	}
+	
+	{
+
+		var ab = new Uint8Array(data.length + 2);
+
+		ab[0] = lws_meta_cmd.WRITE;
+		ab[1] = this.channel_id;
+		ab.set(data, 2);
+	
+		return this.parent.real.send(ab);
+	}
+}
+
+lws_meta_ws_child.prototype.close = function(close_code, close_string)
+{
+	var pkt = new Uint8Array(129), m = 0, pkt1;
+	
+	pkt[m++] = lws_meta_cmd.CLOSE_RQ;
+	pkt[m++] = this.channel_id;
+	
+	pkt[m++] = close_string.length + 0x20;
+	
+	pkt[m++] = close_code / 256;
+	pkt[m++] = close_code % 256;
+	
+	for (i = 0; i < close_string.length; i++)
+		pkt[m++] = close_string.charCodeAt(i);
+	
+	pkt1 = new Uint8Array(m);
+	for (n = 0; n < m; n++)
+		pkt1[n] = pkt[n];
+		
+	this.parent.real.send(pkt1.buffer);
+}
+
+/* make a real ws connection using lws_meta*/
+lws_meta_ws.prototype.new_parent = function(urlpath)
+{
+	var n, i, m = 0, pkt1;
+	
+	this.ordinal = 1;
+	this.pending_children = [];
+	this.active_children = [];
+	this.real = new_ws(urlpath, "lws-meta");
+	
+	this.real.binaryType = 'arraybuffer';
+	this.real.myparent = this;
+
+	this.real.onopen = function() {
+		pkt = new Uint8Array(1024);
+			var n, i, m = 0, pkt1;
+		console.log("real open - pending children " + this.myparent.pending_children.length);
+		for (n = 0; n < this.myparent.pending_children.length; n++) {
+		
+			var p = this.myparent.pending_children[n];
+		
+			pkt[m++] = lws_meta_cmd.OPEN_SUBCHANNEL;
+			for (i = 0; i < p.subprotocol.length; i++)
+				pkt[m++] = p.subprotocol.charCodeAt(i);
+			pkt[m++] = 0;
+			for (i = 0; i < p.suburl.length; i++)
+				pkt[m++] = p.suburl.charCodeAt(i);
+			pkt[m++] = 0;
+			for (i = 0; i < p.cookie.length; i++)
+				pkt[m++] = p.cookie.charCodeAt(i);
+			pkt[m++] = 0;
+		}
+		
+		pkt1 = new Uint8Array(m);
+		for (n = 0; n < m; n++)
+			pkt1[n] = pkt[n];
+		
+		console.log(this.myparent.pending_children[0].subprotocol);
+		console.log(pkt1);
+		
+		this.send(pkt1.buffer);
+	}
+
+
+	this.real.onmessage = function(msg) {
+	
+		if (typeof msg.data != "string") {
+			var ba = new Uint8Array(msg.data), n = 0;
+			
+			while (n < ba.length) {
+
+				switch (ba[n++]) {
+				case lws_meta_cmd.OPEN_RESULT:
+				{
+					var m = 0, cookie = "", protocol = "", ch = 0;
+					var ws = this.myparent;
+					/* cookie NUL
+					 * channel index + 0x20
+					 * protocol NUL
+					 */
+					 while (ba[n])
+					 	cookie = cookie + String.fromCharCode(ba[n++]);
+					 n++;
+					 ch = ba[n++];
+					 
+					 while (ba[n])
+					 	protocol = protocol + String.fromCharCode(ba[n++]);
+					 	
+					console.log("open result " + cookie + " " + protocol + " " + ch + " pending len " + ws.pending_children.length);
+					
+					for (m = 0; m < ws.pending_children.length; m++) {
+						if (ws.pending_children[m].cookie == cookie) {
+							var newchild = ws.pending_children[m];
+			
+							/* found it */
+							ws.pending_children[m].channel_id = ch;
+							/* add to active children array */
+							ws.active_children.push(ws.pending_children[m]);
+							/* remove from pending children array */
+							ws.pending_children.splice(m, 1);
+							
+							newchild.parent = ws;
+							newchild.extensions = this.extensions;
+							
+							newchild.onopen();
+							
+							console.log("made active " + cookie);
+							break;
+						}
+					}
+					break;
+				}
+	
+				case lws_meta_cmd.CLOSE_NOT:
+				{
+					var code = 0, str = "", ch = 0, m, le;
+					var ba = new Uint8Array(msg.data);
+					/*
+					 * BYTE: channel
+					 * BYTE: MSB status code
+					 * BYTE: LSB status code
+					 * BYTES: rest of message is close status string
+					 */
+					 
+					 ch = ba[n++];
+					 le = ba[n++] - 0x20;
+					 code = ba[n++] * 256;
+					 code += ba[n++];
+					 
+					 while (le--)
+					 	str += String.fromCharCode(ba[n++]);
+					 	
+					console.log("channel id " + ch + " code " + code + " str " + str + " len " + str.length);
+					 	
+					for (m = 0; m < this.myparent.active_children.length; m++)
+						if (this.myparent.active_children[m].channel_id == ch) {
+							var child = this.myparent.active_children[m];
+							var ms = new CloseEvent("close", { code:code, reason:str } );
+							
+							/* reply with close ack */
+							this.send(msg.data);
+							
+							if (child.onclose)
+								child.onclose(ms);
+							
+							this.myparent.active_children.splice(m, 1);
+							break;
+						}
+
+				}
+				} // switch
+			}
+		} else {
+			if (msg.data.charCodeAt(0) == lws_meta_cmd.WRITE ) {
+				var ch = msg.data.charCodeAt(1), m, ms;
+				var ws = this.myparent, ms;
+								
+				for (m = 0; m < ws.active_children.length; m++) {
+					if (ws.active_children[m].channel_id == ch) {
+						ms = new MessageEvent("WebSocket", { data: msg.data.substr(2, msg.data.length - 2) } );
+						if (ws.active_children[m].onmessage)
+							ws.active_children[m].onmessage(ms);
+						break;
+					}
+				}
+			}
+		}
+	}
+	this.real.onclose = function() {
+		var ws = this.myparent, m;
+		for (m = 0; m < ws.active_children.length; m++) {
+			var child = ws.active_children[m];
+			var ms = new CloseEvent("close", { code:1000, reason:"parent closed" } );
+			
+			if (child.onclose)
+				child.onclose(ms);
+		}
+	}
+
+}
+
+
+
+/* make a child connection using existing lws_meta real ws connection */
+lws_meta_ws.prototype.new_ws = function(suburl, protocol)
+{
+	var ch = new lws_meta_ws_child();
+	
+	ch.suburl = suburl;
+	ch.subprotocol = protocol;
+	ch.cookie = "C" + this.ordinal++;
+	
+	this.pending_children.push(ch);
+	
+	if (this.real.readyState == 1)
+		this.real.onopen();
+	
+	return ch;
+}
+
+
+/*
+ * end of lws-meta helpers
+ */
  
 function lws_san(s)
 {

test-server/test-server-v2.0.c

@@ -226,8 +226,15 @@ static const struct lws_protocol_vhost_options pvo_opt4 = {
  * linked-list.  We can also give the plugin per-vhost options here.
  */
 
-static const struct lws_protocol_vhost_options pvo_4 = {
+static const struct lws_protocol_vhost_options pvo_5 = {
 	NULL,
+	NULL,
+	"lws-meta",
+	"" /* ignored, just matches the protocol name above */
+};
+
+static const struct lws_protocol_vhost_options pvo_4 = {
+	&pvo_5,
 	&pvo_opt4, /* set us as the protocol who gets raw connections */
 	"protocol-lws-raw-test",
 	"" /* ignored, just matches the protocol name above */

test-server/test-server.c

@@ -68,6 +68,7 @@ char crl_path[1024] = "";
 #define LWS_PLUGIN_STATIC
 #include "../plugins/protocol_lws_mirror.c"
 #include "../plugins/protocol_lws_status.c"
+#include "../plugins/protocol_lws_meta.c"
 
 /* singlethreaded version --> no locks */
 
@@ -104,6 +105,8 @@ enum demo_protocols {
 	PROTOCOL_LWS_MIRROR,
 	PROTOCOL_LWS_STATUS,
 
+	PROTOCOL_LWS_META,
+
 	/* always last */
 	DEMO_PROTOCOL_COUNT
 };
@@ -130,6 +133,8 @@ static struct lws_protocols protocols[] = {
 	},
 	LWS_PLUGIN_PROTOCOL_MIRROR,
 	LWS_PLUGIN_PROTOCOL_LWS_STATUS,
+
+	LWS_PLUGIN_PROTOCOL_LWS_META,
 	{ NULL, NULL, 0, 0 } /* terminator */
 };
 

test-server/test.html

@@ -533,21 +533,31 @@ if (params.mirror)
 	mirror_name = params.mirror;
 
 	console.log(mirror_name);
+	
 
-function new_ws(urlpath, protocol)
-{
-	if (typeof MozWebSocket != "undefined")
-		return new MozWebSocket(urlpath, protocol);
+/*
+ * if using lws-meta to carry the other ws connections, declare the
+ * parent connection object and start its connection to the server.
+ *
+ * These helpers are defined in lws-common.js
+ */
 
-	return new WebSocket(get_appropriate_ws_url(urlpath), protocol);
-}
+
+var lws_meta = new lws_meta_ws();
+lws_meta.new_parent(get_appropriate_ws_url("?mirror=" + mirror_name));
 
 
 document.getElementById("number").textContent = get_appropriate_ws_url(mirror_name);
 
 /* dumb increment protocol */
+
+	/*
+	 * to connect via an lws-meta connection, start the connection using
+	 * lws_meta.new_ws().  To connect by independent connection, start
+	 * the connection using just new_ws()
+	 */
 	
-	var socket_di = new_ws("", "dumb-increment-protocol");
+	var socket_di = lws_meta.new_ws("", "dumb-increment-protocol");
 
 	try {
 		socket_di.onopen = function() {
@@ -571,8 +581,8 @@ document.getElementById("number").textContent = get_appropriate_ws_url(mirror_na
 	
 	var socket_status, jso, s;
 
-	socket_status = new_ws(get_appropriate_ws_url(""), "lws-status");
 
+	socket_status = lws_meta.new_ws(get_appropriate_ws_url(""), "lws-status");
 
 	try {
 		socket_status.onopen = function() {
@@ -585,6 +595,8 @@ document.getElementById("number").textContent = get_appropriate_ws_url(mirror_na
 		socket_status.onmessage =function got_packet(msg) {
 			var s;
 			
+			console.log(msg.data);
+			
 			jso = JSON.parse(msg.data);
 			
 			document.getElementById("servinfo").innerHTML = 
@@ -637,7 +649,9 @@ var socket_ot;
 
 function ot_open() {
 
-	socket_ot = new_ws(get_appropriate_ws_url(""), "dumb-increment-protocol");
+	socket_ot = lws_meta.new_ws(get_appropriate_ws_url(""), "dumb-increment-protocol");
+
+	console.log("ot_open");
 
 	try {
 		socket_ot.onopen = function() {
@@ -646,6 +660,7 @@ function ot_open() {
 			document.getElementById("ot_open_btn").disabled = true;
 			document.getElementById("ot_close_btn").disabled = false;
 			document.getElementById("ot_req_close_btn").disabled = false;
+			console.log("ot_open.onopen");
 		} 
 
 		socket_ot.onclose = function(e){
@@ -680,7 +695,7 @@ function ot_req_close() {
 	var socket_lm;
 	var color = "#000000";
 
-	socket_lm = new_ws(get_appropriate_ws_url("?mirror=" + mirror_name),
+	socket_lm = lws_meta.new_ws(get_appropriate_ws_url("?mirror=" + mirror_name),
 			"lws-mirror-protocol");
 
 	try {