/*
 * libwebsockets - small server side websockets and web server implementation
 *
 * Copyright (C) 2010-2014 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"

int
lws_handshake_client(struct lws *wsi, unsigned char **buf, size_t len)
{
	int m;

	switch (wsi->mode) {
	case LWSCM_WSCL_WAITING_PROXY_REPLY:
	case LWSCM_WSCL_ISSUE_HANDSHAKE:
	case LWSCM_WSCL_WAITING_SERVER_REPLY:
	case LWSCM_WSCL_WAITING_EXTENSION_CONNECT:
	case LWSCM_WS_CLIENT:
		while (len) {
			/*
			 * we were accepting input but now we stopped doing so
			 */
			if (!(wsi->rxflow_change_to & LWS_RXFLOW_ALLOW)) {
				lwsl_debug("%s: caching %d\n", __func__, len);
				lws_rxflow_cache(wsi, *buf, 0, len);
				return 0;
			}
			if (wsi->u.ws.rx_draining_ext) {
				m = lws_rx_sm(wsi, 0);
				if (m < 0)
					return -1;
				continue;
			}
			/* account for what we're using in rxflow buffer */
			if (wsi->rxflow_buffer)
				wsi->rxflow_pos++;

			if (lws_client_rx_sm(wsi, *(*buf)++)) {
				lwsl_debug("client_rx_sm exited\n");
				return -1;
			}
			len--;
		}
		lwsl_debug("%s: finished with %d\n", __func__, len);
		return 0;
	default:
		break;
	}

	return 0;
}

int
lws_client_socket_service(struct lws_context *context, struct lws *wsi,
			  struct lws_pollfd *pollfd)
{
	struct lws_context_per_thread *pt = &context->pt[(int)wsi->tsi];
	char *p = (char *)&pt->serv_buf[0];
	char *sb = p;
	unsigned char c;
	int n, len;

	switch (wsi->mode) {

	case LWSCM_WSCL_WAITING_CONNECT:

		/*
		 * we are under PENDING_TIMEOUT_SENT_CLIENT_HANDSHAKE
		 * timeout protection set in client-handshake.c
		 */

		if (!lws_client_connect_2(wsi)) {
			/* closed */
			lwsl_client("closed\n");
			return -1;
		}

		/* either still pending connection, or changed mode */
		return 0;

	case LWSCM_WSCL_WAITING_PROXY_REPLY:

		/* handle proxy hung up on us */

		if (pollfd->revents & LWS_POLLHUP) {

			lwsl_warn("Proxy connection %p (fd=%d) dead\n",
				  (void *)wsi, pollfd->fd);

			lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS);
			return 0;
		}

		n = recv(wsi->sock, sb, LWS_MAX_SOCKET_IO_BUF, 0);
		if (n < 0) {
			if (LWS_ERRNO == LWS_EAGAIN) {
				lwsl_debug("Proxy read returned EAGAIN... retrying\n");
				return 0;
			}

			lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS);
			lwsl_err("ERROR reading from proxy socket\n");
			return 0;
		}

		pt->serv_buf[13] = '\0';
		if (strcmp(sb, "HTTP/1.0 200 ") &&
		    strcmp(sb, "HTTP/1.1 200 ")) {
			lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS);
			lwsl_err("ERROR proxy: %s\n", sb);
			return 0;
		}

		/* clear his proxy connection timeout */

		lws_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);

		/* fallthru */

	case LWSCM_WSCL_ISSUE_HANDSHAKE:

		/*
		 * we are under PENDING_TIMEOUT_SENT_CLIENT_HANDSHAKE
		 * timeout protection set in client-handshake.c
		 *
		 * take care of our lws_callback_on_writable
		 * happening at a time when there's no real connection yet
		 */
		if (lws_change_pollfd(wsi, LWS_POLLOUT, 0))
			return -1;

#ifdef LWS_OPENSSL_SUPPORT
		/* we can retry this... just cook the SSL BIO the first time */

		if (wsi->use_ssl && !wsi->ssl) {
#if defined(CYASSL_SNI_HOST_NAME) || defined(WOLFSSL_SNI_HOST_NAME) || defined(SSL_CTRL_SET_TLSEXT_HOSTNAME)
			const char *hostname = lws_hdr_simple_ptr(wsi,
						_WSI_TOKEN_CLIENT_HOST);
#endif

			wsi->ssl = SSL_new(context->ssl_client_ctx);
#ifndef USE_WOLFSSL
			SSL_set_mode(wsi->ssl,
					SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
#endif
			/*
			 * use server name indication (SNI), if supported,
			 * when establishing connection
			 */
#ifdef USE_WOLFSSL
#ifdef USE_OLD_CYASSL
#ifdef CYASSL_SNI_HOST_NAME
			CyaSSL_UseSNI(wsi->ssl, CYASSL_SNI_HOST_NAME,
				hostname, strlen(hostname));
#endif
#else
#ifdef WOLFSSL_SNI_HOST_NAME
			wolfSSL_UseSNI(wsi->ssl, WOLFSSL_SNI_HOST_NAME,
				hostname, strlen(hostname));
#endif
#endif
#else
#ifdef SSL_CTRL_SET_TLSEXT_HOSTNAME
			SSL_set_tlsext_host_name(wsi->ssl, hostname);
#endif
#endif

#ifdef USE_WOLFSSL
			/*
			 * wolfSSL/CyaSSL does certificate verification differently
			 * from OpenSSL.
			 * If we should ignore the certificate, we need to set
			 * this before SSL_new and SSL_connect is called.
			 * Otherwise the connect will simply fail with error
			 * code -155
			 */
#ifdef USE_OLD_CYASSL
			if (wsi->use_ssl == 2)
				CyaSSL_set_verify(wsi->ssl,
							SSL_VERIFY_NONE, NULL);
#else
			if (wsi->use_ssl == 2)
				wolfSSL_set_verify(wsi->ssl,
							SSL_VERIFY_NONE, NULL);
#endif
#endif /* USE_WOLFSSL */

			wsi->client_bio =
				BIO_new_socket(wsi->sock, BIO_NOCLOSE);
			SSL_set_bio(wsi->ssl, wsi->client_bio, wsi->client_bio);

#ifdef USE_WOLFSSL
#ifdef USE_OLD_CYASSL
			CyaSSL_set_using_nonblock(wsi->ssl, 1);
#else
			wolfSSL_set_using_nonblock(wsi->ssl, 1);
#endif
#else
			BIO_set_nbio(wsi->client_bio, 1); /* nonblocking */
#endif

			SSL_set_ex_data(wsi->ssl,
					openssl_websocket_private_data_index,
								       context);
		}

		if (wsi->use_ssl) {
			lws_latency_pre(context, wsi);
			n = SSL_connect(wsi->ssl);
			lws_latency(context, wsi,
			  "SSL_connect LWSCM_WSCL_ISSUE_HANDSHAKE", n, n > 0);

			if (n < 0) {
				n = SSL_get_error(wsi->ssl, n);

				if (n == SSL_ERROR_WANT_READ)
					goto some_wait;

				if (n == SSL_ERROR_WANT_WRITE) {
					/*
					 * wants us to retry connect due to
					 * state of the underlying ssl layer...
					 * but since it may be stalled on
					 * blocked write, no incoming data may
					 * arrive to trigger the retry.
					 * Force (possibly many times if the SSL
					 * state persists in returning the
					 * condition code, but other sockets
					 * are getting serviced inbetweentimes)
					 * us to get called back when writable.
					 */
					lwsl_info("%s: WANT_WRITE... retrying\n", __func__);
					lws_callback_on_writable(wsi);
some_wait:
					wsi->mode = LWSCM_WSCL_WAITING_SSL;

					return 0; /* no error */
				}
				n = -1;
			}

			if (n <= 0) {
				/*
				 * retry if new data comes until we
				 * run into the connection timeout or win
				 */
				n = ERR_get_error();
				if (n != SSL_ERROR_NONE) {
					lwsl_err("SSL connect error %lu: %s\n",
						n, ERR_error_string(n, sb));
					return 0;
				}
			}
		} else
			wsi->ssl = NULL;

		/* fallthru */

	case LWSCM_WSCL_WAITING_SSL:

		if (wsi->use_ssl) {
			if (wsi->mode == LWSCM_WSCL_WAITING_SSL) {
				lws_latency_pre(context, wsi);
				n = SSL_connect(wsi->ssl);
				lws_latency(context, wsi,
					    "SSL_connect LWSCM_WSCL_WAITING_SSL",
					    n, n > 0);

				if (n < 0) {
					n = SSL_get_error(wsi->ssl, n);

					if (n == SSL_ERROR_WANT_READ)
						goto some_wait;

					if (n == SSL_ERROR_WANT_WRITE) {
						/*
						 * wants us to retry connect due to
						 * state of the underlying ssl layer...
						 * but since it may be stalled on
						 * blocked write, no incoming data may
						 * arrive to trigger the retry.
						 * Force (possibly many times if the SSL
						 * state persists in returning the
						 * condition code, but other sockets
						 * are getting serviced inbetweentimes)
						 * us to get called back when writable.
						 */
						lwsl_info("SSL_connect WANT_WRITE... retrying\n");
						lws_callback_on_writable(wsi);

						goto some_wait;
					}
					n = -1;
				}

				if (n <= 0) {
					/*
					 * retry if new data comes until we
					 * run into the connection timeout or win
					 */
					n = ERR_get_error();
					if (n != SSL_ERROR_NONE) {
						lwsl_err("SSL connect error %lu: %s\n",
							 n, ERR_error_string(n, sb));
						return 0;
					}
				}
			}

			#ifndef USE_WOLFSSL
			/*
			 * See comment above about wolfSSL certificate
			 * verification
			 */
			lws_latency_pre(context, wsi);
			n = SSL_get_verify_result(wsi->ssl);
			lws_latency(context, wsi,
				"SSL_get_verify_result LWS_CONNMODE..HANDSHAKE",
								      n, n > 0);

			if (n != X509_V_OK) {
				if ((n == X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT ||
				     n == X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN) && wsi->use_ssl == 2) {
					lwsl_notice("accepting self-signed certificate\n");
				} else {
					lwsl_err("server's cert didn't look good, X509_V_ERR = %d: %s\n",
						 n, ERR_error_string(n, sb));
					lws_close_free_wsi(wsi,
						LWS_CLOSE_STATUS_NOSTATUS);
					return 0;
				}
			}
#endif /* USE_WOLFSSL */
		} else
			wsi->ssl = NULL;
#endif

		wsi->mode = LWSCM_WSCL_ISSUE_HANDSHAKE2;
		lws_set_timeout(wsi, PENDING_TIMEOUT_AWAITING_CLIENT_HS_SEND,
				context->timeout_secs);

		/* fallthru */

	case LWSCM_WSCL_ISSUE_HANDSHAKE2:
		p = lws_generate_client_handshake(wsi, p);
		if (p == NULL) {
			lwsl_err("Failed to generate handshake for client\n");
			lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS);
			return 0;
		}

		/* send our request to the server */

		lws_latency_pre(context, wsi);

		n = lws_ssl_capable_write(wsi, (unsigned char *)sb, p - sb);
		lws_latency(context, wsi, "send lws_issue_raw", n,
			    n == p - sb);
		switch (n) {
		case LWS_SSL_CAPABLE_ERROR:
			lwsl_debug("ERROR writing to client socket\n");
			lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS);
			return 0;
		case LWS_SSL_CAPABLE_MORE_SERVICE:
			lws_callback_on_writable(wsi);
			break;
		}

		wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
		wsi->u.hdr.lextable_pos = 0;
		wsi->mode = LWSCM_WSCL_WAITING_SERVER_REPLY;
		lws_set_timeout(wsi, PENDING_TIMEOUT_AWAITING_SERVER_RESPONSE,
				context->timeout_secs);
		break;

	case LWSCM_WSCL_WAITING_SERVER_REPLY:

		/* handle server hung up on us */

		if (pollfd->revents & LWS_POLLHUP) {

			lwsl_debug("Server connection %p (fd=%d) dead\n",
				(void *)wsi, pollfd->fd);

			goto bail3;
		}

		if (!(pollfd->revents & LWS_POLLIN))
			break;

		/* interpret the server response */

		/*
		 *  HTTP/1.1 101 Switching Protocols
		 *  Upgrade: websocket
		 *  Connection: Upgrade
		 *  Sec-WebSocket-Accept: me89jWimTRKTWwrS3aRrL53YZSo=
		 *  Sec-WebSocket-Nonce: AQIDBAUGBwgJCgsMDQ4PEC==
		 *  Sec-WebSocket-Protocol: chat
		 */

		/*
		 * we have to take some care here to only take from the
		 * socket bytewise.  The browser may (and has been seen to
		 * in the case that onopen() performs websocket traffic)
		 * coalesce both handshake response and websocket traffic
		 * in one packet, since at that point the connection is
		 * definitively ready from browser pov.
		 */
		len = 1;
		while (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE &&
		       len > 0) {
			n = lws_ssl_capable_read(wsi, &c, 1);
			lws_latency(context, wsi, "send lws_issue_raw", n,
				    n == 1);
			switch (n) {
			case 0:
			case LWS_SSL_CAPABLE_ERROR:
				goto bail3;
			case LWS_SSL_CAPABLE_MORE_SERVICE:
				return 0;
			}

			if (lws_parse(wsi, c)) {
				lwsl_warn("problems parsing header\n");
				goto bail3;
			}
		}

		/*
		 * hs may also be coming in multiple packets, there is a 5-sec
		 * libwebsocket timeout still active here too, so if parsing did
		 * not complete just wait for next packet coming in this state
		 */

		if (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE)
			break;

		/*
		 * otherwise deal with the handshake.  If there's any
		 * packet traffic already arrived we'll trigger poll() again
		 * right away and deal with it that way
		 */

		return lws_client_interpret_server_handshake(wsi);

bail3:
		lwsl_info("closing conn at LWS_CONNMODE...SERVER_REPLY\n");
		lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS);
		return -1;

	case LWSCM_WSCL_WAITING_EXTENSION_CONNECT:
		lwsl_ext("LWSCM_WSCL_WAITING_EXTENSION_CONNECT\n");
		break;

	case LWSCM_WSCL_PENDING_CANDIDATE_CHILD:
		lwsl_ext("LWSCM_WSCL_PENDING_CANDIDATE_CHILD\n");
		break;
	default:
		break;
	}

	return 0;
}

/*
 * In-place str to lower case
 */

static void
strtolower(char *s)
{
	while (*s) {
		*s = tolower((int)*s);
		s++;
	}
}

int
lws_client_interpret_server_handshake(struct lws *wsi)
{
	int n, len, okay = 0, isErrorCodeReceived = 0, port = 0, ssl = 0;
	struct lws_context *context = wsi->context;
	int close_reason = LWS_CLOSE_STATUS_PROTOCOL_ERR;
	const char *pc, *prot, *ads = NULL, *path;
	char *p;
#ifndef LWS_NO_EXTENSIONS
	struct lws_context_per_thread *pt = &context->pt[(int)wsi->tsi];
	char *sb = (char *)&pt->serv_buf[0];
	const struct lws_ext_options *opts;
	const struct lws_extension *ext;
	char ext_name[128];
	const char *c, *a;
	char ignore;
	int more = 1;
	void *v;
#endif

	/*
	 * well, what the server sent looked reasonable for syntax.
	 * Now let's confirm it sent all the necessary headers
	 */
	p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_HTTP);
	if (!p) {
		lwsl_info("no URI\n");
		goto bail3;
	}
	n = atoi(p);
	if (n == 301 || n == 302 || n == 303 || n == 307 || n == 308) {
		p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_HTTP_LOCATION);
		if (!p)
			goto bail3;

		if (lws_parse_uri(p, &prot, &ads, &port, &path))
			goto bail3;

		if (!strcmp(prot, "wss://") || !strcmp(prot, "https://"))
			ssl = 1;

		if (lws_client_reset(wsi, ssl, ads, port, path, ads)) {
			lwsl_err("Redirect failed\n");
			goto bail3;
		}
		return 0;
	}
	if (lws_hdr_total_length(wsi, WSI_TOKEN_ACCEPT) == 0) {
		lwsl_info("no ACCEPT\n");
		isErrorCodeReceived = 1;
		goto bail3;
	}

	if (p && strncmp(p, "101", 3)) {
		lwsl_warn(
		       "lws_client_handshake: got bad HTTP response '%s'\n", p);
		goto bail3;
	}

	p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_UPGRADE);
	if (!p) {
		lwsl_info("no UPGRADE\n");
		goto bail3;
	}
	strtolower(p);
	if (strcmp(p, "websocket")) {
		lwsl_warn(
		      "lws_client_handshake: got bad Upgrade header '%s'\n", p);
		goto bail3;
	}

	p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_CONNECTION);
	if (!p) {
		lwsl_info("no Connection hdr\n");
		goto bail3;
	}
	strtolower(p);
	if (strcmp(p, "upgrade")) {
		lwsl_warn("lws_client_int_s_hs: bad header %s\n", p);
		goto bail3;
	}

	pc = lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS);
	if (!pc) {
		lwsl_parser("lws_client_int_s_hs: no protocol list\n");
	} else
		lwsl_parser("lws_client_int_s_hs: protocol list '%s'\n", pc);

	/*
	 * confirm the protocol the server wants to talk was in the list
	 * of protocols we offered
	 */

	len = lws_hdr_total_length(wsi, WSI_TOKEN_PROTOCOL);
	if (!len) {
		lwsl_info("lws_client_int_s_hs: WSI_TOKEN_PROTOCOL is null\n");
		/*
		 * no protocol name to work from,
		 * default to first protocol
		 */
		wsi->protocol = &context->protocols[0];
		goto check_extensions;
	}

	p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_PROTOCOL);
	len = strlen(p);

	while (pc && *pc && !okay) {
		if (!strncmp(pc, p, len) &&
		    (pc[len] == ',' || pc[len] == '\0')) {
			okay = 1;
			continue;
		}
		while (*pc && *pc++ != ',')
			;
		while (*pc && *pc == ' ')
			pc++;
	}

	if (!okay) {
		lwsl_err("lws_client_int_s_hs: got bad protocol %s\n", p);
		goto bail2;
	}

	/*
	 * identify the selected protocol struct and set it
	 */
	n = 0;
	wsi->protocol = NULL;
	while (context->protocols[n].callback && !wsi->protocol) {
		if (strcmp(p, context->protocols[n].name) == 0) {
			wsi->protocol = &context->protocols[n];
			break;
		}
		n++;
	}

	if (wsi->protocol == NULL) {
		lwsl_err("lws_client_int_s_hs: fail protocol %s\n", p);
		goto bail2;
	}


check_extensions:
#ifndef LWS_NO_EXTENSIONS
	/* instantiate the accepted extensions */

	if (!lws_hdr_total_length(wsi, WSI_TOKEN_EXTENSIONS)) {
		lwsl_ext("no client extensions allowed by server\n");
		goto check_accept;
	}

	/*
	 * break down the list of server accepted extensions
	 * and go through matching them or identifying bogons
	 */

	if (lws_hdr_copy(wsi, sb, LWS_MAX_SOCKET_IO_BUF, WSI_TOKEN_EXTENSIONS) < 0) {
		lwsl_warn("ext list from server failed to copy\n");
		goto bail2;
	}

	c = sb;
	n = 0;
	ignore = 0;
	a = NULL;
	while (more) {

		if (*c && (*c != ',' && *c != '\t')) {
			if (*c == ';') {
				ignore = 1;
				if (!a)
					a = c + 1;
			}
			if (ignore || *c == ' ') {
				c++;
				continue;
			}

			ext_name[n] = *c++;
			if (n < sizeof(ext_name) - 1)
				n++;
			continue;
		}
		ext_name[n] = '\0';
		ignore = 0;
		if (!*c)
			more = 0;
		else {
			c++;
			if (!n)
				continue;
		}

		/* check we actually support it */

		lwsl_notice("checking client ext %s\n", ext_name);

		n = 0;
		ext = lws_get_context(wsi)->extensions;
		while (ext && ext->callback) {
			if (strcmp(ext_name, ext->name)) {
				ext++;
				continue;
			}

			n = 1;
			lwsl_notice("instantiating client ext %s\n", ext_name);

			/* instantiate the extension on this conn */

			wsi->active_extensions[wsi->count_act_ext] = ext;

			/* allow him to construct his ext instance */

			ext->callback(lws_get_context(wsi), ext, wsi,
				      LWS_EXT_CB_CLIENT_CONSTRUCT,
				      (void *)&wsi->act_ext_user[wsi->count_act_ext],
				      (void *)&opts, 0);

			/*
			 * allow the user code to override ext defaults if it
			 * wants to
			 */
			ext_name[0] = '\0';
			if (user_callback_handle_rxflow(wsi->protocol->callback,
					wsi, LWS_CALLBACK_WS_EXT_DEFAULTS,
					(char *)ext->name, ext_name,
					sizeof(ext_name)))
				goto bail2;

			if (ext_name[0] &&
			    lws_ext_parse_options(ext, wsi, wsi->act_ext_user[
						  wsi->count_act_ext], opts, ext_name,
						  strlen(ext_name))) {
				lwsl_err("%s: unable to parse user defaults '%s'",
					 __func__, ext_name);
				goto bail2;
			}

			/*
			 * give the extension the server options
			 */
			if (a && lws_ext_parse_options(ext, wsi,
					wsi->act_ext_user[wsi->count_act_ext],
					opts, a, c - a)) {
				lwsl_err("%s: unable to parse remote def '%s'",
					 __func__, a);
				goto bail2;
			}

			if (ext->callback(lws_get_context(wsi), ext, wsi,
					LWS_EXT_CB_OPTION_CONFIRM,
				      wsi->act_ext_user[wsi->count_act_ext],
				      NULL, 0)) {
				lwsl_err("%s: ext %s rejects server options %s",
					 ext->name, a);
				goto bail2;
			}

			wsi->count_act_ext++;

			ext++;
		}

		if (n == 0) {
			lwsl_warn("Unknown ext '%s'!\n", ext_name);
			goto bail2;
		}

		a = NULL;
		n = 0;
	}

check_accept:
#endif

	/*
	 * Confirm his accept token is the one we precomputed
	 */

	p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_ACCEPT);
	if (strcmp(p, wsi->u.hdr.ah->initial_handshake_hash_base64)) {
		lwsl_warn("lws_client_int_s_hs: accept '%s' wrong vs '%s'\n", p,
				  wsi->u.hdr.ah->initial_handshake_hash_base64);
		goto bail2;
	}

	/* allocate the per-connection user memory (if any) */
	if (lws_ensure_user_space(wsi)) {
		lwsl_err("Problem allocating wsi user mem\n");
		goto bail2;
	}

	/*
	 * we seem to be good to go, give client last chance to check
	 * headers and OK it
	 */
	if (wsi->protocol->callback(wsi, LWS_CALLBACK_CLIENT_FILTER_PRE_ESTABLISH,
				    wsi->user_space, NULL, 0))
		goto bail2;

	/* clear his proxy connection timeout */
	lws_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);

	/* free up his parsing allocations */
	lws_header_table_detach(wsi);

	lws_union_transition(wsi, LWSCM_WS_CLIENT);
	wsi->state = LWSS_ESTABLISHED;

	wsi->rxflow_change_to = LWS_RXFLOW_ALLOW;

	/*
	 * create the frame buffer for this connection according to the
	 * size mentioned in the protocol definition.  If 0 there, then
	 * use a big default for compatibility
	 */
	n = wsi->protocol->rx_buffer_size;
	if (!n)
		n = LWS_MAX_SOCKET_IO_BUF;
	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);
		goto bail2;
	}
       wsi->u.ws.rx_ubuf_alloc = n;
	lwsl_info("Allocating client RX buffer %d\n", n);

	if (setsockopt(wsi->sock, SOL_SOCKET, SO_SNDBUF, (const char *)&n,
		       sizeof n)) {
		lwsl_warn("Failed to set SNDBUF to %d", n);
		goto bail3;
	}

	lwsl_debug("handshake OK for protocol %s\n", wsi->protocol->name);

	/* call him back to inform him he is up */

	if (wsi->protocol->callback(wsi, LWS_CALLBACK_CLIENT_ESTABLISHED,
				    wsi->user_space, NULL, 0))
		goto bail3;
#ifndef LWS_NO_EXTENSIONS
	/*
	 * inform all extensions, not just active ones since they
	 * already know
	 */
	ext = context->extensions;

	while (ext && ext->callback) {
		v = NULL;
		for (n = 0; n < wsi->count_act_ext; n++)
			if (wsi->active_extensions[n] == ext)
				v = wsi->act_ext_user[n];

		ext->callback(context, ext, wsi,
			  LWS_EXT_CB_ANY_WSI_ESTABLISHED, v, NULL, 0);
		ext++;
	}
#endif

	return 0;

bail3:
	close_reason = LWS_CLOSE_STATUS_NOSTATUS;

bail2:
	if (wsi->protocol && wsi->state == LWSS_ESTABLISHED) {
		if (isErrorCodeReceived && p) {
			wsi->protocol->callback(wsi,
				LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
						wsi->user_space, p,
						(unsigned int)strlen(p));
		} else {
			wsi->protocol->callback(wsi,
				LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
						wsi->user_space, NULL, 0);
		}
	}

	lwsl_info("closing connection due to bail2 connection error\n");

	/* closing will free up his parsing allocations */
	lws_close_free_wsi(wsi, close_reason);

	return 1;
}


char *
lws_generate_client_handshake(struct lws *wsi, char *pkt)
{
	char buf[128], hash[20], key_b64[40], *p = pkt;
	struct lws_context *context = wsi->context;
	int n;
#ifndef LWS_NO_EXTENSIONS
	const struct lws_extension *ext;
	int ext_count = 0;
#endif

	/*
	 * create the random key
	 */
	n = lws_get_random(context, hash, 16);
	if (n != 16) {
		lwsl_err("Unable to read from random dev %s\n",
			 SYSTEM_RANDOM_FILEPATH);
		lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS);
		return NULL;
	}

	lws_b64_encode_string(hash, 16, key_b64, sizeof(key_b64));

	/*
	 * 00 example client handshake
	 *
	 * GET /socket.io/websocket HTTP/1.1
	 * Upgrade: WebSocket
	 * Connection: Upgrade
	 * Host: 127.0.0.1:9999
	 * Origin: http://127.0.0.1
	 * Sec-WebSocket-Key1: 1 0 2#0W 9 89 7  92 ^
	 * Sec-WebSocket-Key2: 7 7Y 4328 B2v[8(z1
	 * Cookie: socketio=websocket
	 *
	 * (Á®Ä0¶†≥
	 *
	 * 04 example client handshake
	 *
	 * GET /chat HTTP/1.1
	 * Host: server.example.com
	 * Upgrade: websocket
	 * Connection: Upgrade
	 * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
	 * Sec-WebSocket-Origin: http://example.com
	 * Sec-WebSocket-Protocol: chat, superchat
	 * Sec-WebSocket-Version: 4
	 */

	p += sprintf(p, "GET %s HTTP/1.1\x0d\x0a",
		     lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_URI));

	p += sprintf(p, "Pragma: no-cache\x0d\x0a"
			"Cache-Control: no-cache\x0d\x0a");

	p += sprintf(p, "Host: %s\x0d\x0a",
		     lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_HOST));
	p += sprintf(p, "Upgrade: websocket\x0d\x0a"
			"Connection: Upgrade\x0d\x0a"
			"Sec-WebSocket-Key: ");
	strcpy(p, key_b64);
	p += strlen(key_b64);
	p += sprintf(p, "\x0d\x0a");
	if (lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_ORIGIN))
		p += sprintf(p, "Origin: http://%s\x0d\x0a",
			     lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_ORIGIN));

	if (lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS))
		p += sprintf(p, "Sec-WebSocket-Protocol: %s\x0d\x0a",
		     lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS));

	/* tell the server what extensions we could support */

	p += sprintf(p, "Sec-WebSocket-Extensions: ");
#ifndef LWS_NO_EXTENSIONS
	ext = context->extensions;
	while (ext && ext->callback) {
		n = lws_ext_cb_all_exts(context, wsi,
			   LWS_EXT_CB_CHECK_OK_TO_PROPOSE_EXTENSION,
			   (char *)ext->name, 0);
		if (n) { /* an extension vetos us */
			lwsl_ext("ext %s vetoed\n", (char *)ext->name);
			ext++;
			continue;
		}
		n = context->protocols[0].callback(wsi,
			LWS_CALLBACK_CLIENT_CONFIRM_EXTENSION_SUPPORTED,
				wsi->user_space, (char *)ext->name, 0);

		/*
		 * zero return from callback means
		 * go ahead and allow the extension,
		 * it's what we get if the callback is
		 * unhandled
		 */

		if (n) {
			ext++;
			continue;
		}

		/* apply it */

		if (ext_count)
			*p++ = ',';
		p += sprintf(p, "%s", ext->client_offer);
		ext_count++;

		ext++;
	}
#endif
	p += sprintf(p, "\x0d\x0a");

	if (wsi->ietf_spec_revision)
		p += sprintf(p, "Sec-WebSocket-Version: %d\x0d\x0a",
			     wsi->ietf_spec_revision);

	/* give userland a chance to append, eg, cookies */

	context->protocols[0].callback(wsi, LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
				       NULL, &p, (pkt + LWS_MAX_SOCKET_IO_BUF) - p - 12);

	p += sprintf(p, "\x0d\x0a");

	/* prepare the expected server accept response */

	key_b64[39] = '\0'; /* enforce composed length below buf sizeof */
	n = sprintf(buf, "%s258EAFA5-E914-47DA-95CA-C5AB0DC85B11", key_b64);

	lws_SHA1((unsigned char *)buf, n, (unsigned char *)hash);

	lws_b64_encode_string(hash, 20,
			      wsi->u.hdr.ah->initial_handshake_hash_base64,
			      sizeof(wsi->u.hdr.ah->initial_handshake_hash_base64));

	return p;
}

