lib/http2.c - platform/external/libwebsockets - Gitiles

 /*
  * libwebsockets - small server side websockets and web server implementation
  *
  * Copyright (C) 2010-2013 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
  */


 #include "private-libwebsockets.h"

 const struct http2_settings lws_http2_default_settings = { {
 	0,
 	/* LWS_HTTP2_SETTINGS__HEADER_TABLE_SIZE */		4096,
 	/* LWS_HTTP2_SETTINGS__ENABLE_PUSH */			   1,
 	/* LWS_HTTP2_SETTINGS__MAX_CONCURRENT_STREAMS */	 100,
 	/* LWS_HTTP2_SETTINGS__INITIAL_WINDOW_SIZE */	       65535,
 	/* LWS_HTTP2_SETTINGS__MAX_FRAME_SIZE */	       16384,
 	/* LWS_HTTP2_SETTINGS__MAX_HEADER_LIST_SIZE */		  ~0,
 }};


 void lws_http2_init(struct http2_settings *settings)
 {
 	memcpy(settings, lws_http2_default_settings.setting, sizeof(*settings));
 }

 struct lws *
 lws_http2_wsi_from_id(struct lws *wsi, unsigned int sid)
 {
 	do {
 		if (wsi->u.http2.my_stream_id == sid)
 			return wsi;

 		wsi = wsi->u.http2.next_child_wsi;
 	} while (wsi);

 	return NULL;
 }

 struct lws *
 lws_create_server_child_wsi(struct lws_context *context, struct lws *parent_wsi, unsigned int sid)
 {
 	struct lws *wsi = lws_create_new_server_wsi(context);

 	if (!wsi)
 		return NULL;

 	/* no more children allowed by parent */
 	if (parent_wsi->u.http2.child_count + 1 == parent_wsi->u.http2.peer_settings.setting[LWS_HTTP2_SETTINGS__MAX_CONCURRENT_STREAMS])
 		return NULL;

 	lws_http2_init(&wsi->u.http2.peer_settings);
 	lws_http2_init(&wsi->u.http2.my_settings);
 	wsi->u.http2.stream_id = sid;
 	wsi->u.http2.my_stream_id = sid;

 	wsi->u.http2.parent_wsi = parent_wsi;
 	wsi->u.http2.next_child_wsi = parent_wsi->u.http2.next_child_wsi;
 	parent_wsi->u.http2.next_child_wsi = wsi;
 	parent_wsi->u.http2.child_count++;

 	wsi->u.http2.my_priority = 16;
 	wsi->u.http2.tx_credit = 65535;

 	wsi->state = WSI_STATE_HTTP2_ESTABLISHED;
 	wsi->mode = parent_wsi->mode;

 	wsi->protocol = &context->protocols[0];
 	lws_ensure_user_space(wsi);

 	lwsl_info("%s: %p new child %p, sid %d, user_space=%p\n", __func__, parent_wsi, wsi, sid, wsi->user_space);

 	return wsi;
 }

 int lws_remove_server_child_wsi(struct lws_context *context, struct lws *wsi)
 {
 	struct lws **w = &wsi->u.http2.parent_wsi;
 	do {
 		if (*w == wsi) {
 			*w = wsi->u.http2.next_child_wsi;
 			(wsi->u.http2.parent_wsi)->u.http2.child_count--;
 			return 0;
 		}

 		w = &((*w)->u.http2.next_child_wsi);
 	} while (*w);

 	lwsl_err("%s: can't find %p\n", __func__, wsi);
 	return 1;
 }

 int
 lws_http2_interpret_settings_payload(struct http2_settings *settings, unsigned char *buf, int len)
 {
 	unsigned int a, b;

 	if (!len)
 		return 0;

 	if (len < LWS_HTTP2_SETTINGS_LENGTH)
 		return 1;

 	while (len >= LWS_HTTP2_SETTINGS_LENGTH) {
 		a = (buf[0] << 8) | buf[1];
 		if (a < LWS_HTTP2_SETTINGS__COUNT) {
 			b = buf[2] << 24 | buf[3] << 16 | buf[4] << 8 | buf[5];
 			settings->setting[a] = b;
 			lwsl_info("http2 settings %d <- 0x%x\n", a, b);
 		}
 		len -= LWS_HTTP2_SETTINGS_LENGTH;
 		buf += LWS_HTTP2_SETTINGS_LENGTH;
 	}

 	if (len)
 		return 1;

 	return 0;
 }

 struct lws *lws_http2_get_network_wsi(struct lws *wsi)
 {
 	while (wsi->u.http2.parent_wsi)
 		wsi = wsi->u.http2.parent_wsi;

 	return wsi;
 }

 int lws_http2_frame_write(struct lws *wsi, int type, int flags, unsigned int sid, unsigned int len, unsigned char *buf)
 {
 	struct lws *wsi_eff = lws_http2_get_network_wsi(wsi);
 	unsigned char *p = &buf[-LWS_HTTP2_FRAME_HEADER_LENGTH];
 	int n;

 	*p++ = len >> 16;
 	*p++ = len >> 8;
 	*p++ = len;
 	*p++ = type;
 	*p++ = flags;
 	*p++ = sid >> 24;
 	*p++ = sid >> 16;
 	*p++ = sid >> 8;
 	*p++ = sid;

 	lwsl_info("%s: %p (eff %p). type %d, flags 0x%x, sid=%d, len=%d\n",
 		  __func__, wsi, wsi_eff, type, flags, sid, len, wsi->u.http2.tx_credit);

 	if (type == LWS_HTTP2_FRAME_TYPE_DATA) {
 		if (wsi->u.http2.tx_credit < len)
 			lwsl_err("%s: %p: sending payload len %d but tx_credit only %d!\n", len, wsi->u.http2.tx_credit);
 		wsi->u.http2.tx_credit -= len;
 	}

 	n = lws_issue_raw(wsi_eff, &buf[-LWS_HTTP2_FRAME_HEADER_LENGTH], len + LWS_HTTP2_FRAME_HEADER_LENGTH);
 	if (n >= LWS_HTTP2_FRAME_HEADER_LENGTH)
 		return n - LWS_HTTP2_FRAME_HEADER_LENGTH;

 	return n;
 }

 static void lws_http2_settings_write(struct lws *wsi, int n, unsigned char *buf)
 {
 	*buf++ = n >> 8;
 	*buf++ = n;
 	*buf++ = wsi->u.http2.my_settings.setting[n] >> 24;
 	*buf++ = wsi->u.http2.my_settings.setting[n] >> 16;
 	*buf++ = wsi->u.http2.my_settings.setting[n] >> 8;
 	*buf = wsi->u.http2.my_settings.setting[n];
 }

 static const char * https_client_preface =
 	"PRI * HTTP/2.0\x0d\x0a\x0d\x0aSM\x0d\x0a\x0d\x0a";

 int
 lws_http2_parser(struct lws_context *context,
 		     struct lws *wsi, unsigned char c)
 {
 	struct lws *swsi;
 	int n;
 	//dstruct lws *wsi_new;

 	switch (wsi->state) {
 	case WSI_STATE_HTTP2_AWAIT_CLIENT_PREFACE:
 		if (https_client_preface[wsi->u.http2.count++] != c)
 			return 1;

 		if (!https_client_preface[wsi->u.http2.count]) {
 			lwsl_info("http2: %p: established\n", wsi);
 			wsi->state = WSI_STATE_HTTP2_ESTABLISHED_PRE_SETTINGS;
 			wsi->u.http2.count = 0;
 			wsi->u.http2.tx_credit = 65535;

 			/*
 			 * we must send a settings frame -- empty one is OK...
 			 * that must be the first thing sent by server
 			 * and the peer must send a SETTINGS with ACK flag...
 			 */

 			lws_set_protocol_write_pending(context, wsi, LWS_PPS_HTTP2_MY_SETTINGS);
 		}
 		break;

 	case WSI_STATE_HTTP2_ESTABLISHED_PRE_SETTINGS:
 	case WSI_STATE_HTTP2_ESTABLISHED:
 		if (wsi->u.http2.frame_state == LWS_HTTP2_FRAME_HEADER_LENGTH) { // payload
 			wsi->u.http2.count++;
 			wsi->u.http2.stream_wsi->u.http2.count = wsi->u.http2.count;
 			/* applies to wsi->u.http2.stream_wsi which may be wsi*/
 			switch(wsi->u.http2.type) {
 			case LWS_HTTP2_FRAME_TYPE_SETTINGS:
 				wsi->u.http2.stream_wsi->u.http2.one_setting[wsi->u.http2.count % LWS_HTTP2_SETTINGS_LENGTH] = c;
 				if (wsi->u.http2.count % LWS_HTTP2_SETTINGS_LENGTH == LWS_HTTP2_SETTINGS_LENGTH - 1)
 					if (lws_http2_interpret_settings_payload(
 					     &wsi->u.http2.stream_wsi->u.http2.peer_settings,
 					     wsi->u.http2.one_setting,
 					     LWS_HTTP2_SETTINGS_LENGTH))
 						return 1;
 				break;
 			case LWS_HTTP2_FRAME_TYPE_CONTINUATION:
 			case LWS_HTTP2_FRAME_TYPE_HEADERS:
 				lwsl_info(" %02X\n", c);
 				if (lws_hpack_interpret(context, wsi->u.http2.stream_wsi, c))
 					return 1;
 				break;
 			case LWS_HTTP2_FRAME_TYPE_GOAWAY:
 				if (wsi->u.http2.count >= 5 && wsi->u.http2.count <= 8) {
 					wsi->u.http2.hpack_e_dep <<= 8;
 					wsi->u.http2.hpack_e_dep |= c;
 					if (wsi->u.http2.count == 8) {
 						lwsl_info("goaway err 0x%x\n", wsi->u.http2.hpack_e_dep);
 					}
 				}
 				wsi->u.http2.GOING_AWAY = 1;
 				break;
 			case LWS_HTTP2_FRAME_TYPE_DATA:
 				break;
 			case LWS_HTTP2_FRAME_TYPE_PRIORITY:
 				break;
 			case LWS_HTTP2_FRAME_TYPE_RST_STREAM:
 				break;
 			case LWS_HTTP2_FRAME_TYPE_PUSH_PROMISE:
 				break;
 			case LWS_HTTP2_FRAME_TYPE_PING:
 				if (wsi->u.http2.flags & LWS_HTTP2_FLAG_SETTINGS_ACK) { // ack
 				} else { /* they're sending us a ping request */
 					if (wsi->u.http2.count > 8)
 						return 1;
 					wsi->u.http2.ping_payload[wsi->u.http2.count - 1] = c;
 				}
 				break;
 			case LWS_HTTP2_FRAME_TYPE_WINDOW_UPDATE:
 				wsi->u.http2.hpack_e_dep <<= 8;
 				wsi->u.http2.hpack_e_dep |= c;
 				break;
 			}
 			if (wsi->u.http2.count != wsi->u.http2.length)
 				break;

 			/* end of frame */

 			wsi->u.http2.frame_state = 0;
 			wsi->u.http2.count = 0;
 			swsi = wsi->u.http2.stream_wsi;
 			/* set our initial window size */
 			if (!wsi->u.http2.initialized) {
 				wsi->u.http2.tx_credit = wsi->u.http2.peer_settings.setting[LWS_HTTP2_SETTINGS__INITIAL_WINDOW_SIZE];
 				lwsl_info("initial tx credit on master conn %p: %d\n", wsi, wsi->u.http2.tx_credit);
 				wsi->u.http2.initialized = 1;
 			}
 			switch (wsi->u.http2.type) {
 			case LWS_HTTP2_FRAME_TYPE_HEADERS:
 				/* service the http request itself */
 				lwsl_info("servicing initial http request, wsi=%p, stream wsi=%p\n", wsi, wsi->u.http2.stream_wsi);
 				n = lws_http_action(context, swsi);
 				(void)n;
 				lwsl_info("  action result %d\n", n);
 				break;
 			case LWS_HTTP2_FRAME_TYPE_PING:
 				if (wsi->u.http2.flags & LWS_HTTP2_FLAG_SETTINGS_ACK) { // ack
 				} else { /* they're sending us a ping request */
 					lws_set_protocol_write_pending(context, wsi, LWS_PPS_HTTP2_PONG);
 				}
 				break;
 			case LWS_HTTP2_FRAME_TYPE_WINDOW_UPDATE:
 				wsi->u.http2.hpack_e_dep &= ~(1 << 31);
 				if ((long long)swsi->u.http2.tx_credit + (unsigned long long)wsi->u.http2.hpack_e_dep > (~(1 << 31)))
 					return 1; /* actually need to close swsi not the whole show */
 				swsi->u.http2.tx_credit += wsi->u.http2.hpack_e_dep;
 				if (swsi->u.http2.waiting_tx_credit && swsi->u.http2.tx_credit > 0) {
 					lwsl_info("%s: %p: waiting_tx_credit -> wait on writeable\n", __func__, wsi);
 					swsi->u.http2.waiting_tx_credit = 0;
 					lws_callback_on_writable(context, swsi);
 				}
 				break;
 			}
 			break;
 		}
 		switch (wsi->u.http2.frame_state++) {
 		case 0:
 			wsi->u.http2.length = c;
 			break;
 		case 1:
 		case 2:
 			wsi->u.http2.length <<= 8;
 			wsi->u.http2.length |= c;
 			break;
 		case 3:
 			wsi->u.http2.type = c;
 			break;
 		case 4:
 			wsi->u.http2.flags = c;
 			break;
 		case 5:
 		case 6:
 		case 7:
 		case 8:
 			wsi->u.http2.stream_id <<= 8;
 			wsi->u.http2.stream_id |= c;
 			break;
 		}
 		if (wsi->u.http2.frame_state == LWS_HTTP2_FRAME_HEADER_LENGTH) { /* frame header complete */
 			lwsl_info("frame: type 0x%x, flags 0x%x, sid 0x%x, len 0x%x\n",
 				  wsi->u.http2.type, wsi->u.http2.flags, wsi->u.http2.stream_id, wsi->u.http2.length);
 			wsi->u.http2.count = 0;

 			wsi->u.http2.stream_wsi = wsi;
 			if (wsi->u.http2.stream_id)
 				wsi->u.http2.stream_wsi = lws_http2_wsi_from_id(wsi, wsi->u.http2.stream_id);

 			switch (wsi->u.http2.type) {
 			case LWS_HTTP2_FRAME_TYPE_SETTINGS:
 				/* nonzero sid on settings is illegal */
 				if (wsi->u.http2.stream_id)
 					return 1;

 				if (wsi->u.http2.flags & LWS_HTTP2_FLAG_SETTINGS_ACK) { // ack
 				} else
 					/* non-ACK coming in means we must ACK it */
 					lws_set_protocol_write_pending(context, wsi, LWS_PPS_HTTP2_ACK_SETTINGS);
 				break;
 			case LWS_HTTP2_FRAME_TYPE_PING:
 				if (wsi->u.http2.stream_id)
 					return 1;
 				if (wsi->u.http2.length != 8)
 					return 1;
 				break;
 			case LWS_HTTP2_FRAME_TYPE_CONTINUATION:
 				if (wsi->u.http2.END_HEADERS)
 					return 1;
 				goto update_end_headers;

 			case LWS_HTTP2_FRAME_TYPE_HEADERS:
 				lwsl_info("LWS_HTTP2_FRAME_TYPE_HEADERS: stream_id = %d\n", wsi->u.http2.stream_id);
 				if (!wsi->u.http2.stream_id)
 					return 1;
 				if (!wsi->u.http2.stream_wsi)
 					wsi->u.http2.stream_wsi = lws_create_server_child_wsi(context, wsi, wsi->u.http2.stream_id);

 				/* END_STREAM means after servicing this, close the stream */
 				wsi->u.http2.END_STREAM = !!(wsi->u.http2.flags & LWS_HTTP2_FLAG_END_STREAM);
 				lwsl_info("%s: headers END_STREAM = %d\n",__func__, wsi->u.http2.END_STREAM);
 update_end_headers:
 				/* no END_HEADERS means CONTINUATION must come */
 				wsi->u.http2.END_HEADERS = !!(wsi->u.http2.flags & LWS_HTTP2_FLAG_END_HEADERS);

 				swsi = wsi->u.http2.stream_wsi;
 				if (!swsi)
 					return 1;


 				/* prepare the hpack parser at the right start */

 				swsi->u.http2.flags = wsi->u.http2.flags;
 				swsi->u.http2.length = wsi->u.http2.length;
 				swsi->u.http2.END_STREAM = wsi->u.http2.END_STREAM;

 				if (swsi->u.http2.flags & LWS_HTTP2_FLAG_PADDED)
 					swsi->u.http2.hpack = HPKS_OPT_PADDING;
 				else
 					if (swsi->u.http2.flags & LWS_HTTP2_FLAG_PRIORITY) {
 						swsi->u.http2.hpack = HKPS_OPT_E_DEPENDENCY;
 						swsi->u.http2.hpack_m = 4;
 					} else
 						swsi->u.http2.hpack = HPKS_TYPE;
 				lwsl_info("initial hpack state %d\n", swsi->u.http2.hpack);
 				break;
 			case LWS_HTTP2_FRAME_TYPE_WINDOW_UPDATE:
 				if (wsi->u.http2.length != 4)
 					return 1;
 				break;
 			}
 			if (wsi->u.http2.length == 0)
 				wsi->u.http2.frame_state = 0;

 		}
 		break;
 	}

 	return 0;
 }

 int lws_http2_do_pps_send(struct lws_context *context, struct lws *wsi)
 {
 	unsigned char settings[LWS_SEND_BUFFER_PRE_PADDING + 6 * LWS_HTTP2_SETTINGS__COUNT];
 	struct lws *swsi;
 	int n, m = 0;

 	lwsl_debug("%s: %p: %d\n", __func__, wsi, wsi->pps);

 	switch (wsi->pps) {
 	case LWS_PPS_HTTP2_MY_SETTINGS:
 		for (n = 1; n < LWS_HTTP2_SETTINGS__COUNT; n++)
 			if (wsi->u.http2.my_settings.setting[n] != lws_http2_default_settings.setting[n]) {
 				lws_http2_settings_write(wsi, n,
 							 &settings[LWS_SEND_BUFFER_PRE_PADDING + m]);
 				m += sizeof(wsi->u.http2.one_setting);
 			}
 		n = lws_http2_frame_write(wsi, LWS_HTTP2_FRAME_TYPE_SETTINGS,
 		     			  0, LWS_HTTP2_STREAM_ID_MASTER, m,
 		     			  &settings[LWS_SEND_BUFFER_PRE_PADDING]);
 		if (n != m) {
 			lwsl_info("send %d %d\n", n, m);
 			return 1;
 		}
 		break;
 	case LWS_PPS_HTTP2_ACK_SETTINGS:
 		/* send ack ... always empty */
 		n = lws_http2_frame_write(wsi, LWS_HTTP2_FRAME_TYPE_SETTINGS,
 			1, LWS_HTTP2_STREAM_ID_MASTER, 0,
 			&settings[LWS_SEND_BUFFER_PRE_PADDING]);
 		if (n) {
 			lwsl_err("ack tells %d\n", n);
 			return 1;
 		}
 		/* this is the end of the preface dance then? */
 		if (wsi->state == WSI_STATE_HTTP2_ESTABLISHED_PRE_SETTINGS) {
 			wsi->state = WSI_STATE_HTTP2_ESTABLISHED;

 			wsi->u.http.fd = LWS_INVALID_FILE;

 			if (lws_is_ssl(lws_http2_get_network_wsi(wsi))) {
 				lwsl_info("skipping nonexistant ssl upgrade headers\n");
 				break;
 			}

 			/*
 			 * we need to treat the headers from this upgrade
 			 * as the first job.  These need to get
 			 * shifted to stream ID 1
 			 */
 			lwsl_info("%s: setting up sid 1\n", __func__);

 			swsi = wsi->u.http2.stream_wsi = lws_create_server_child_wsi(context, wsi, 1);
 			/* pass on the initial headers to SID 1 */
 			swsi->u.http.ah = wsi->u.http.ah;
 			wsi->u.http.ah = NULL;

 			lwsl_info("%s: inherited headers %p\n", __func__, swsi->u.http.ah);
 			swsi->u.http2.tx_credit = wsi->u.http2.peer_settings.setting[LWS_HTTP2_SETTINGS__INITIAL_WINDOW_SIZE];
 			lwsl_info("initial tx credit on conn %p: %d\n", swsi, swsi->u.http2.tx_credit);
 			swsi->u.http2.initialized = 1;
 			/* demanded by HTTP2 */
 			swsi->u.http2.END_STREAM = 1;
 			lwsl_info("servicing initial http request\n");
 			return lws_http_action(context, swsi);
 		}
 		break;
 	case LWS_PPS_HTTP2_PONG:
 		memcpy(&settings[LWS_SEND_BUFFER_PRE_PADDING], wsi->u.http2.ping_payload, 8);
 		n = lws_http2_frame_write(wsi, LWS_HTTP2_FRAME_TYPE_PING,
 		     			  LWS_HTTP2_FLAG_SETTINGS_ACK,
 			    		  LWS_HTTP2_STREAM_ID_MASTER, 8,
 		     			  &settings[LWS_SEND_BUFFER_PRE_PADDING]);
 		if (n != 8) {
 			lwsl_info("send %d %d\n", n, m);
 			return 1;
 		}
 		break;
 	default:
 		break;
 	}

 	return 0;
 }

 struct lws * lws_http2_get_nth_child(struct lws *wsi, int n)
 {
 	do {
 		wsi = wsi->u.http2.next_child_wsi;
 		if (!wsi)
 			return NULL;
 	} while (n--);

 	return wsi;
 }
	/*
	* libwebsockets - small server side websockets and web server implementation
	*
	* Copyright (C) 2010-2013 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
	*/


	#include "private-libwebsockets.h"

	const struct http2_settings lws_http2_default_settings = { {
	0,
	/* LWS_HTTP2_SETTINGS__HEADER_TABLE_SIZE */ 4096,
	/* LWS_HTTP2_SETTINGS__ENABLE_PUSH */ 1,
	/* LWS_HTTP2_SETTINGS__MAX_CONCURRENT_STREAMS */ 100,
	/* LWS_HTTP2_SETTINGS__INITIAL_WINDOW_SIZE */ 65535,
	/* LWS_HTTP2_SETTINGS__MAX_FRAME_SIZE */ 16384,
	/* LWS_HTTP2_SETTINGS__MAX_HEADER_LIST_SIZE */ ~0,
	}};


	void lws_http2_init(struct http2_settings *settings)
	{
	memcpy(settings, lws_http2_default_settings.setting, sizeof(*settings));
	}

	struct lws *
	lws_http2_wsi_from_id(struct lws *wsi, unsigned int sid)
	{
	do {
	if (wsi->u.http2.my_stream_id == sid)
	return wsi;

	wsi = wsi->u.http2.next_child_wsi;
	} while (wsi);

	return NULL;
	}

	struct lws *
	lws_create_server_child_wsi(struct lws_context context, struct lws parent_wsi, unsigned int sid)
	{
	struct lws *wsi = lws_create_new_server_wsi(context);

	if (!wsi)
	return NULL;

	/* no more children allowed by parent */
	if (parent_wsi->u.http2.child_count + 1 == parent_wsi->u.http2.peer_settings.setting[LWS_HTTP2_SETTINGS__MAX_CONCURRENT_STREAMS])
	return NULL;

	lws_http2_init(&wsi->u.http2.peer_settings);
	lws_http2_init(&wsi->u.http2.my_settings);
	wsi->u.http2.stream_id = sid;
	wsi->u.http2.my_stream_id = sid;

	wsi->u.http2.parent_wsi = parent_wsi;
	wsi->u.http2.next_child_wsi = parent_wsi->u.http2.next_child_wsi;
	parent_wsi->u.http2.next_child_wsi = wsi;
	parent_wsi->u.http2.child_count++;

	wsi->u.http2.my_priority = 16;
	wsi->u.http2.tx_credit = 65535;

	wsi->state = WSI_STATE_HTTP2_ESTABLISHED;
	wsi->mode = parent_wsi->mode;

	wsi->protocol = &context->protocols[0];
	lws_ensure_user_space(wsi);

	lwsl_info("%s: %p new child %p, sid %d, user_space=%p\n", __func__, parent_wsi, wsi, sid, wsi->user_space);

	return wsi;
	}

	int lws_remove_server_child_wsi(struct lws_context context, struct lws wsi)
	{
	struct lws **w = &wsi->u.http2.parent_wsi;
	do {
	if (*w == wsi) {
	*w = wsi->u.http2.next_child_wsi;
	(wsi->u.http2.parent_wsi)->u.http2.child_count--;
	return 0;
	}

	w = &((*w)->u.http2.next_child_wsi);
	} while (*w);

	lwsl_err("%s: can't find %p\n", __func__, wsi);
	return 1;
	}

	int
	lws_http2_interpret_settings_payload(struct http2_settings settings, unsigned char buf, int len)
	{
	unsigned int a, b;

	if (!len)
	return 0;

	if (len < LWS_HTTP2_SETTINGS_LENGTH)
	return 1;

	while (len >= LWS_HTTP2_SETTINGS_LENGTH) {
	a = (buf[0] << 8) \| buf[1];
	if (a < LWS_HTTP2_SETTINGS__COUNT) {
	b = buf[2] << 24 \| buf[3] << 16 \| buf[4] << 8 \| buf[5];
	settings->setting[a] = b;
	lwsl_info("http2 settings %d <- 0x%x\n", a, b);
	}
	len -= LWS_HTTP2_SETTINGS_LENGTH;
	buf += LWS_HTTP2_SETTINGS_LENGTH;
	}

	if (len)
	return 1;

	return 0;
	}

	struct lws lws_http2_get_network_wsi(struct lws wsi)
	{
	while (wsi->u.http2.parent_wsi)
	wsi = wsi->u.http2.parent_wsi;

	return wsi;
	}

	int lws_http2_frame_write(struct lws wsi, int type, int flags, unsigned int sid, unsigned int len, unsigned char buf)
	{
	struct lws *wsi_eff = lws_http2_get_network_wsi(wsi);
	unsigned char *p = &buf[-LWS_HTTP2_FRAME_HEADER_LENGTH];
	int n;

	*p++ = len >> 16;
	*p++ = len >> 8;
	*p++ = len;
	*p++ = type;
	*p++ = flags;
	*p++ = sid >> 24;
	*p++ = sid >> 16;
	*p++ = sid >> 8;
	*p++ = sid;

	lwsl_info("%s: %p (eff %p). type %d, flags 0x%x, sid=%d, len=%d\n",
	__func__, wsi, wsi_eff, type, flags, sid, len, wsi->u.http2.tx_credit);

	if (type == LWS_HTTP2_FRAME_TYPE_DATA) {
	if (wsi->u.http2.tx_credit < len)
	lwsl_err("%s: %p: sending payload len %d but tx_credit only %d!\n", len, wsi->u.http2.tx_credit);
	wsi->u.http2.tx_credit -= len;
	}

	n = lws_issue_raw(wsi_eff, &buf[-LWS_HTTP2_FRAME_HEADER_LENGTH], len + LWS_HTTP2_FRAME_HEADER_LENGTH);
	if (n >= LWS_HTTP2_FRAME_HEADER_LENGTH)
	return n - LWS_HTTP2_FRAME_HEADER_LENGTH;

	return n;
	}

	static void lws_http2_settings_write(struct lws wsi, int n, unsigned char buf)
	{
	*buf++ = n >> 8;
	*buf++ = n;
	*buf++ = wsi->u.http2.my_settings.setting[n] >> 24;
	*buf++ = wsi->u.http2.my_settings.setting[n] >> 16;
	*buf++ = wsi->u.http2.my_settings.setting[n] >> 8;
	*buf = wsi->u.http2.my_settings.setting[n];
	}

	static const char * https_client_preface =
	"PRI * HTTP/2.0\x0d\x0a\x0d\x0aSM\x0d\x0a\x0d\x0a";

	int
	lws_http2_parser(struct lws_context *context,
	struct lws *wsi, unsigned char c)
	{
	struct lws *swsi;
	int n;
	//dstruct lws *wsi_new;

	switch (wsi->state) {
	case WSI_STATE_HTTP2_AWAIT_CLIENT_PREFACE:
	if (https_client_preface[wsi->u.http2.count++] != c)
	return 1;

	if (!https_client_preface[wsi->u.http2.count]) {
	lwsl_info("http2: %p: established\n", wsi);
	wsi->state = WSI_STATE_HTTP2_ESTABLISHED_PRE_SETTINGS;
	wsi->u.http2.count = 0;
	wsi->u.http2.tx_credit = 65535;

	/*
	* we must send a settings frame -- empty one is OK...
	* that must be the first thing sent by server
	* and the peer must send a SETTINGS with ACK flag...
	*/

	lws_set_protocol_write_pending(context, wsi, LWS_PPS_HTTP2_MY_SETTINGS);
	}
	break;

	case WSI_STATE_HTTP2_ESTABLISHED_PRE_SETTINGS:
	case WSI_STATE_HTTP2_ESTABLISHED:
	if (wsi->u.http2.frame_state == LWS_HTTP2_FRAME_HEADER_LENGTH) { // payload
	wsi->u.http2.count++;
	wsi->u.http2.stream_wsi->u.http2.count = wsi->u.http2.count;
	/* applies to wsi->u.http2.stream_wsi which may be wsi*/
	switch(wsi->u.http2.type) {
	case LWS_HTTP2_FRAME_TYPE_SETTINGS:
	wsi->u.http2.stream_wsi->u.http2.one_setting[wsi->u.http2.count % LWS_HTTP2_SETTINGS_LENGTH] = c;
	if (wsi->u.http2.count % LWS_HTTP2_SETTINGS_LENGTH == LWS_HTTP2_SETTINGS_LENGTH - 1)
	if (lws_http2_interpret_settings_payload(
	&wsi->u.http2.stream_wsi->u.http2.peer_settings,
	wsi->u.http2.one_setting,
	LWS_HTTP2_SETTINGS_LENGTH))
	return 1;
	break;
	case LWS_HTTP2_FRAME_TYPE_CONTINUATION:
	case LWS_HTTP2_FRAME_TYPE_HEADERS:
	lwsl_info(" %02X\n", c);
	if (lws_hpack_interpret(context, wsi->u.http2.stream_wsi, c))
	return 1;
	break;
	case LWS_HTTP2_FRAME_TYPE_GOAWAY:
	if (wsi->u.http2.count >= 5 && wsi->u.http2.count <= 8) {
	wsi->u.http2.hpack_e_dep <<= 8;
	wsi->u.http2.hpack_e_dep \|= c;
	if (wsi->u.http2.count == 8) {
	lwsl_info("goaway err 0x%x\n", wsi->u.http2.hpack_e_dep);
	}
	}
	wsi->u.http2.GOING_AWAY = 1;
	break;
	case LWS_HTTP2_FRAME_TYPE_DATA:
	break;
	case LWS_HTTP2_FRAME_TYPE_PRIORITY:
	break;
	case LWS_HTTP2_FRAME_TYPE_RST_STREAM:
	break;
	case LWS_HTTP2_FRAME_TYPE_PUSH_PROMISE:
	break;
	case LWS_HTTP2_FRAME_TYPE_PING:
	if (wsi->u.http2.flags & LWS_HTTP2_FLAG_SETTINGS_ACK) { // ack
	} else { /* they're sending us a ping request */
	if (wsi->u.http2.count > 8)
	return 1;
	wsi->u.http2.ping_payload[wsi->u.http2.count - 1] = c;
	}
	break;
	case LWS_HTTP2_FRAME_TYPE_WINDOW_UPDATE:
	wsi->u.http2.hpack_e_dep <<= 8;
	wsi->u.http2.hpack_e_dep \|= c;
	break;
	}
	if (wsi->u.http2.count != wsi->u.http2.length)
	break;

	/* end of frame */

	wsi->u.http2.frame_state = 0;
	wsi->u.http2.count = 0;
	swsi = wsi->u.http2.stream_wsi;
	/* set our initial window size */
	if (!wsi->u.http2.initialized) {
	wsi->u.http2.tx_credit = wsi->u.http2.peer_settings.setting[LWS_HTTP2_SETTINGS__INITIAL_WINDOW_SIZE];
	lwsl_info("initial tx credit on master conn %p: %d\n", wsi, wsi->u.http2.tx_credit);
	wsi->u.http2.initialized = 1;
	}
	switch (wsi->u.http2.type) {
	case LWS_HTTP2_FRAME_TYPE_HEADERS:
	/* service the http request itself */
	lwsl_info("servicing initial http request, wsi=%p, stream wsi=%p\n", wsi, wsi->u.http2.stream_wsi);
	n = lws_http_action(context, swsi);
	(void)n;
	lwsl_info(" action result %d\n", n);
	break;
	case LWS_HTTP2_FRAME_TYPE_PING:
	if (wsi->u.http2.flags & LWS_HTTP2_FLAG_SETTINGS_ACK) { // ack
	} else { /* they're sending us a ping request */
	lws_set_protocol_write_pending(context, wsi, LWS_PPS_HTTP2_PONG);
	}
	break;
	case LWS_HTTP2_FRAME_TYPE_WINDOW_UPDATE:
	wsi->u.http2.hpack_e_dep &= ~(1 << 31);
	if ((long long)swsi->u.http2.tx_credit + (unsigned long long)wsi->u.http2.hpack_e_dep > (~(1 << 31)))
	return 1; /* actually need to close swsi not the whole show */
	swsi->u.http2.tx_credit += wsi->u.http2.hpack_e_dep;
	if (swsi->u.http2.waiting_tx_credit && swsi->u.http2.tx_credit > 0) {
	lwsl_info("%s: %p: waiting_tx_credit -> wait on writeable\n", __func__, wsi);
	swsi->u.http2.waiting_tx_credit = 0;
	lws_callback_on_writable(context, swsi);
	}
	break;
	}
	break;
	}
	switch (wsi->u.http2.frame_state++) {
	case 0:
	wsi->u.http2.length = c;
	break;
	case 1:
	case 2:
	wsi->u.http2.length <<= 8;
	wsi->u.http2.length \|= c;
	break;
	case 3:
	wsi->u.http2.type = c;
	break;
	case 4:
	wsi->u.http2.flags = c;
	break;
	case 5:
	case 6:
	case 7:
	case 8:
	wsi->u.http2.stream_id <<= 8;
	wsi->u.http2.stream_id \|= c;
	break;
	}
	if (wsi->u.http2.frame_state == LWS_HTTP2_FRAME_HEADER_LENGTH) { /* frame header complete */
	lwsl_info("frame: type 0x%x, flags 0x%x, sid 0x%x, len 0x%x\n",
	wsi->u.http2.type, wsi->u.http2.flags, wsi->u.http2.stream_id, wsi->u.http2.length);
	wsi->u.http2.count = 0;

	wsi->u.http2.stream_wsi = wsi;
	if (wsi->u.http2.stream_id)
	wsi->u.http2.stream_wsi = lws_http2_wsi_from_id(wsi, wsi->u.http2.stream_id);

	switch (wsi->u.http2.type) {
	case LWS_HTTP2_FRAME_TYPE_SETTINGS:
	/* nonzero sid on settings is illegal */
	if (wsi->u.http2.stream_id)
	return 1;

	if (wsi->u.http2.flags & LWS_HTTP2_FLAG_SETTINGS_ACK) { // ack
	} else
	/* non-ACK coming in means we must ACK it */
	lws_set_protocol_write_pending(context, wsi, LWS_PPS_HTTP2_ACK_SETTINGS);
	break;
	case LWS_HTTP2_FRAME_TYPE_PING:
	if (wsi->u.http2.stream_id)
	return 1;
	if (wsi->u.http2.length != 8)
	return 1;
	break;
	case LWS_HTTP2_FRAME_TYPE_CONTINUATION:
	if (wsi->u.http2.END_HEADERS)
	return 1;
	goto update_end_headers;

	case LWS_HTTP2_FRAME_TYPE_HEADERS:
	lwsl_info("LWS_HTTP2_FRAME_TYPE_HEADERS: stream_id = %d\n", wsi->u.http2.stream_id);
	if (!wsi->u.http2.stream_id)
	return 1;
	if (!wsi->u.http2.stream_wsi)
	wsi->u.http2.stream_wsi = lws_create_server_child_wsi(context, wsi, wsi->u.http2.stream_id);

	/* END_STREAM means after servicing this, close the stream */
	wsi->u.http2.END_STREAM = !!(wsi->u.http2.flags & LWS_HTTP2_FLAG_END_STREAM);
	lwsl_info("%s: headers END_STREAM = %d\n",__func__, wsi->u.http2.END_STREAM);
	update_end_headers:
	/* no END_HEADERS means CONTINUATION must come */
	wsi->u.http2.END_HEADERS = !!(wsi->u.http2.flags & LWS_HTTP2_FLAG_END_HEADERS);

	swsi = wsi->u.http2.stream_wsi;
	if (!swsi)
	return 1;


	/* prepare the hpack parser at the right start */

	swsi->u.http2.flags = wsi->u.http2.flags;
	swsi->u.http2.length = wsi->u.http2.length;
	swsi->u.http2.END_STREAM = wsi->u.http2.END_STREAM;

	if (swsi->u.http2.flags & LWS_HTTP2_FLAG_PADDED)
	swsi->u.http2.hpack = HPKS_OPT_PADDING;
	else
	if (swsi->u.http2.flags & LWS_HTTP2_FLAG_PRIORITY) {
	swsi->u.http2.hpack = HKPS_OPT_E_DEPENDENCY;
	swsi->u.http2.hpack_m = 4;
	} else
	swsi->u.http2.hpack = HPKS_TYPE;
	lwsl_info("initial hpack state %d\n", swsi->u.http2.hpack);
	break;
	case LWS_HTTP2_FRAME_TYPE_WINDOW_UPDATE:
	if (wsi->u.http2.length != 4)
	return 1;
	break;
	}
	if (wsi->u.http2.length == 0)
	wsi->u.http2.frame_state = 0;

	}
	break;
	}

	return 0;
	}

	int lws_http2_do_pps_send(struct lws_context context, struct lws wsi)
	{
	unsigned char settings[LWS_SEND_BUFFER_PRE_PADDING + 6 * LWS_HTTP2_SETTINGS__COUNT];
	struct lws *swsi;
	int n, m = 0;

	lwsl_debug("%s: %p: %d\n", __func__, wsi, wsi->pps);

	switch (wsi->pps) {
	case LWS_PPS_HTTP2_MY_SETTINGS:
	for (n = 1; n < LWS_HTTP2_SETTINGS__COUNT; n++)
	if (wsi->u.http2.my_settings.setting[n] != lws_http2_default_settings.setting[n]) {
	lws_http2_settings_write(wsi, n,
	&settings[LWS_SEND_BUFFER_PRE_PADDING + m]);
	m += sizeof(wsi->u.http2.one_setting);
	}
	n = lws_http2_frame_write(wsi, LWS_HTTP2_FRAME_TYPE_SETTINGS,
	0, LWS_HTTP2_STREAM_ID_MASTER, m,
	&settings[LWS_SEND_BUFFER_PRE_PADDING]);
	if (n != m) {
	lwsl_info("send %d %d\n", n, m);
	return 1;
	}
	break;
	case LWS_PPS_HTTP2_ACK_SETTINGS:
	/* send ack ... always empty */
	n = lws_http2_frame_write(wsi, LWS_HTTP2_FRAME_TYPE_SETTINGS,
	1, LWS_HTTP2_STREAM_ID_MASTER, 0,
	&settings[LWS_SEND_BUFFER_PRE_PADDING]);
	if (n) {
	lwsl_err("ack tells %d\n", n);
	return 1;
	}
	/* this is the end of the preface dance then? */
	if (wsi->state == WSI_STATE_HTTP2_ESTABLISHED_PRE_SETTINGS) {
	wsi->state = WSI_STATE_HTTP2_ESTABLISHED;

	wsi->u.http.fd = LWS_INVALID_FILE;

	if (lws_is_ssl(lws_http2_get_network_wsi(wsi))) {
	lwsl_info("skipping nonexistant ssl upgrade headers\n");
	break;
	}

	/*
	* we need to treat the headers from this upgrade
	* as the first job. These need to get
	* shifted to stream ID 1
	*/
	lwsl_info("%s: setting up sid 1\n", __func__);

	swsi = wsi->u.http2.stream_wsi = lws_create_server_child_wsi(context, wsi, 1);
	/* pass on the initial headers to SID 1 */
	swsi->u.http.ah = wsi->u.http.ah;
	wsi->u.http.ah = NULL;

	lwsl_info("%s: inherited headers %p\n", __func__, swsi->u.http.ah);
	swsi->u.http2.tx_credit = wsi->u.http2.peer_settings.setting[LWS_HTTP2_SETTINGS__INITIAL_WINDOW_SIZE];
	lwsl_info("initial tx credit on conn %p: %d\n", swsi, swsi->u.http2.tx_credit);
	swsi->u.http2.initialized = 1;
	/* demanded by HTTP2 */
	swsi->u.http2.END_STREAM = 1;
	lwsl_info("servicing initial http request\n");
	return lws_http_action(context, swsi);
	}
	break;
	case LWS_PPS_HTTP2_PONG:
	memcpy(&settings[LWS_SEND_BUFFER_PRE_PADDING], wsi->u.http2.ping_payload, 8);
	n = lws_http2_frame_write(wsi, LWS_HTTP2_FRAME_TYPE_PING,
	LWS_HTTP2_FLAG_SETTINGS_ACK,
	LWS_HTTP2_STREAM_ID_MASTER, 8,
	&settings[LWS_SEND_BUFFER_PRE_PADDING]);
	if (n != 8) {
	lwsl_info("send %d %d\n", n, m);
	return 1;
	}
	break;
	default:
	break;
	}

	return 0;
	}

	struct lws * lws_http2_get_nth_child(struct lws *wsi, int n)
	{
	do {
	wsi = wsi->u.http2.next_child_wsi;
	if (!wsi)
	return NULL;
	} while (n--);

	return wsi;
	}