2 * libwebsockets - small server side websockets and web server implementation
4 * Copyright (C) 2010 Andy Green <andy@warmcat.com>
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation:
9 * version 2.1 of the License.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
22 #ifndef __LIBWEBSOCKET_H__
23 #define __LIBWEBSOCKET_H__
32 #ifndef WIN32_LEAN_AND_MEAN
33 #define WIN32_LEAN_AND_MEAN
38 #include "../win32port/win32helpers/websock-w32.h"
40 #include "../win32port/win32helpers/gettimeofday.h"
42 #define strcasecmp stricmp
48 #define LWS_EXTERN extern __declspec(dllexport)
50 #define LWS_EXTERN extern __declspec(dllimport)
59 #define LWS_EXTERN extern
62 #define CONTEXT_PORT_NO_LISTEN 0
63 #define MAX_MUX_RECURSION 2
65 enum libwebsocket_context_options {
66 LWS_SERVER_OPTION_DEFEAT_CLIENT_MASK = 1,
67 LWS_SERVER_OPTION_REQUIRE_VALID_OPENSSL_CLIENT_CERT = 2,
68 LWS_SERVER_OPTION_SKIP_SERVER_CANONICAL_NAME = 4,
71 enum libwebsocket_callback_reasons {
72 LWS_CALLBACK_ESTABLISHED,
73 LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
74 LWS_CALLBACK_CLIENT_ESTABLISHED,
77 LWS_CALLBACK_CLIENT_RECEIVE,
78 LWS_CALLBACK_CLIENT_RECEIVE_PONG,
79 LWS_CALLBACK_CLIENT_WRITEABLE,
80 LWS_CALLBACK_SERVER_WRITEABLE,
82 LWS_CALLBACK_BROADCAST,
83 LWS_CALLBACK_FILTER_NETWORK_CONNECTION,
84 LWS_CALLBACK_FILTER_PROTOCOL_CONNECTION,
85 LWS_CALLBACK_OPENSSL_LOAD_EXTRA_CLIENT_VERIFY_CERTS,
86 LWS_CALLBACK_OPENSSL_LOAD_EXTRA_SERVER_VERIFY_CERTS,
87 LWS_CALLBACK_OPENSSL_PERFORM_CLIENT_CERT_VERIFICATION,
88 LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
89 LWS_CALLBACK_CONFIRM_EXTENSION_OKAY,
90 LWS_CALLBACK_CLIENT_CONFIRM_EXTENSION_SUPPORTED,
91 /* external poll() management support */
92 LWS_CALLBACK_ADD_POLL_FD,
93 LWS_CALLBACK_DEL_POLL_FD,
94 LWS_CALLBACK_SET_MODE_POLL_FD,
95 LWS_CALLBACK_CLEAR_MODE_POLL_FD,
98 enum libwebsocket_extension_callback_reasons {
99 LWS_EXT_CALLBACK_SERVER_CONTEXT_CONSTRUCT,
100 LWS_EXT_CALLBACK_CLIENT_CONTEXT_CONSTRUCT,
101 LWS_EXT_CALLBACK_SERVER_CONTEXT_DESTRUCT,
102 LWS_EXT_CALLBACK_CLIENT_CONTEXT_DESTRUCT,
103 LWS_EXT_CALLBACK_CONSTRUCT,
104 LWS_EXT_CALLBACK_CLIENT_CONSTRUCT,
105 LWS_EXT_CALLBACK_CHECK_OK_TO_REALLY_CLOSE,
106 LWS_EXT_CALLBACK_CHECK_OK_TO_PROPOSE_EXTENSION,
107 LWS_EXT_CALLBACK_DESTROY,
108 LWS_EXT_CALLBACK_DESTROY_ANY_WSI_CLOSING,
109 LWS_EXT_CALLBACK_ANY_WSI_ESTABLISHED,
110 LWS_EXT_CALLBACK_PACKET_RX_PREPARSE,
111 LWS_EXT_CALLBACK_PACKET_TX_PRESEND,
112 LWS_EXT_CALLBACK_PACKET_TX_DO_SEND,
113 LWS_EXT_CALLBACK_HANDSHAKE_REPLY_TX,
114 LWS_EXT_CALLBACK_FLUSH_PENDING_TX,
115 LWS_EXT_CALLBACK_EXTENDED_PAYLOAD_RX,
116 LWS_EXT_CALLBACK_CAN_PROXY_CLIENT_CONNECTION,
117 LWS_EXT_CALLBACK_1HZ,
118 LWS_EXT_CALLBACK_REQUEST_ON_WRITEABLE,
119 LWS_EXT_CALLBACK_IS_WRITEABLE,
122 enum libwebsocket_write_protocol {
125 LWS_WRITE_CONTINUATION,
128 /* special 04+ opcodes */
136 LWS_WRITE_NO_FIN = 0x40,
138 * client packet payload goes out on wire unmunged
139 * only useful for security tests since normal servers cannot
140 * decode the content if used
142 LWS_WRITE_CLIENT_IGNORE_XOR_MASK = 0x80
146 * you need these to look at headers that have been parsed if using the
147 * LWS_CALLBACK_FILTER_CONNECTION callback. If a header from the enum
148 * list below is absent, .token = NULL and token_len = 0. Otherwise .token
149 * points to .token_len chars containing that header content.
157 enum lws_token_indexes {
160 WSI_TOKEN_CONNECTION,
175 WSI_TOKEN_EXTENSIONS,
177 /* client receives these */
183 /* always last real token index*/
185 /* parser state additions */
188 WSI_TOKEN_SKIPPING_SAW_CR,
189 WSI_PARSING_COMPLETE,
190 WSI_INIT_TOKEN_MUXURL,
197 1000 indicates a normal closure, meaning that the purpose for
198 which the connection was established has been fulfilled.
202 1001 indicates that an endpoint is "going away", such as a server
203 going down or a browser having navigated away from a page.
207 1002 indicates that an endpoint is terminating the connection due
212 1003 indicates that an endpoint is terminating the connection
213 because it has received a type of data it cannot accept (e.g., an
214 endpoint that understands only text data MAY send this if it
215 receives a binary message).
219 Reserved. The specific meaning might be defined in the future.
223 1005 is a reserved value and MUST NOT be set as a status code in a
224 Close control frame by an endpoint. It is designated for use in
225 applications expecting a status code to indicate that no status
226 code was actually present.
230 1006 is a reserved value and MUST NOT be set as a status code in a
231 Close control frame by an endpoint. It is designated for use in
232 applications expecting a status code to indicate that the
233 connection was closed abnormally, e.g., without sending or
234 receiving a Close control frame.
238 1007 indicates that an endpoint is terminating the connection
239 because it has received data within a message that was not
240 consistent with the type of the message (e.g., non-UTF-8 [RFC3629]
241 data within a text message).
245 1008 indicates that an endpoint is terminating the connection
246 because it has received a message that violates its policy. This
247 is a generic status code that can be returned when there is no
248 other more suitable status code (e.g., 1003 or 1009) or if there
249 is a need to hide specific details about the policy.
253 1009 indicates that an endpoint is terminating the connection
254 because it has received a message that is too big for it to
259 1010 indicates that an endpoint (client) is terminating the
260 connection because it has expected the server to negotiate one or
261 more extension, but the server didn't return them in the response
262 message of the WebSocket handshake. The list of extensions that
263 are needed SHOULD appear in the /reason/ part of the Close frame.
264 Note that this status code is not used by the server, because it
265 can fail the WebSocket handshake instead.
269 1011 indicates that a server is terminating the connection because
270 it encountered an unexpected condition that prevented it from
271 fulfilling the request.
275 1015 is a reserved value and MUST NOT be set as a status code in a
276 Close control frame by an endpoint. It is designated for use in
277 applications expecting a status code to indicate that the
278 connection was closed due to a failure to perform a TLS handshake
279 (e.g., the server certificate can't be verified).
282 enum lws_close_status {
283 LWS_CLOSE_STATUS_NOSTATUS = 0,
284 LWS_CLOSE_STATUS_NORMAL = 1000,
285 LWS_CLOSE_STATUS_GOINGAWAY = 1001,
286 LWS_CLOSE_STATUS_PROTOCOL_ERR = 1002,
287 LWS_CLOSE_STATUS_UNACCEPTABLE_OPCODE = 1003,
288 LWS_CLOSE_STATUS_RESERVED = 1004,
289 LWS_CLOSE_STATUS_NO_STATUS = 1005,
290 LWS_CLOSE_STATUS_ABNORMAL_CLOSE = 1006,
291 LWS_CLOSE_STATUS_INVALID_PAYLOAD = 1007,
292 LWS_CLOSE_STATUS_POLICY_VIOLATION = 1008,
293 LWS_CLOSE_STATUS_MESSAGE_TOO_LARGE = 1009,
294 LWS_CLOSE_STATUS_EXTENSION_REQUIRED = 1010,
295 LWS_CLOSE_STATUS_UNEXPECTED_CONDITION = 1011,
296 LWS_CLOSE_STATUS_TLS_FAILURE = 1015,
300 struct libwebsocket_context;
301 struct libwebsocket_extension;
304 * callback_function() - User server actions
305 * @context: Websockets context
306 * @wsi: Opaque websocket instance pointer
307 * @reason: The reason for the call
308 * @user: Pointer to per-session user data allocated by library
309 * @in: Pointer used for some callback reasons
310 * @len: Length set for some callback reasons
312 * This callback is the way the user controls what is served. All the
313 * protocol detail is hidden and handled by the library.
315 * For each connection / session there is user data allocated that is
316 * pointed to by "user". You set the size of this user data area when
317 * the library is initialized with libwebsocket_create_server.
319 * You get an opportunity to initialize user data when called back with
320 * LWS_CALLBACK_ESTABLISHED reason.
322 * LWS_CALLBACK_ESTABLISHED: after the server completes a handshake with
325 * LWS_CALLBACK_CLIENT_CONNECTION_ERROR: the request client connection has
326 * been unable to complete a handshake with the remote server
328 * LWS_CALLBACK_CLIENT_ESTABLISHED: after your client connection completed
329 * a handshake with the remote server
331 * LWS_CALLBACK_CLOSED: when the websocket session ends
333 * LWS_CALLBACK_BROADCAST: signal to send to client (you would use
334 * libwebsocket_write() taking care about the
335 * special buffer requirements
337 * LWS_CALLBACK_RECEIVE: data has appeared for this server endpoint from a
338 * remote client, it can be found at *in and is
341 * LWS_CALLBACK_CLIENT_RECEIVE_PONG: if you elected to see PONG packets,
342 * they appear with this callback reason. PONG
343 * packets only exist in 04+ protocol
345 * LWS_CALLBACK_CLIENT_RECEIVE: data has appeared from the server for the
346 * client connection, it can be found at *in and
349 * LWS_CALLBACK_HTTP: an http request has come from a client that is not
350 * asking to upgrade the connection to a websocket
351 * one. This is a chance to serve http content,
352 * for example, to send a script to the client
353 * which will then open the websockets connection.
354 * @in points to the URI path requested and
355 * libwebsockets_serve_http_file() makes it very
356 * simple to send back a file to the client.
358 * LWS_CALLBACK_CLIENT_WRITEABLE:
359 * LWS_CALLBACK_SERVER_WRITEABLE: If you call
360 * libwebsocket_callback_on_writable() on a connection, you will
361 * get one of these callbacks coming when the connection socket
362 * is able to accept another write packet without blocking.
363 * If it already was able to take another packet without blocking,
364 * you'll get this callback at the next call to the service loop
365 * function. Notice that CLIENTs get LWS_CALLBACK_CLIENT_WRITEABLE
366 * and servers get LWS_CALLBACK_SERVER_WRITEABLE.
368 * LWS_CALLBACK_FILTER_NETWORK_CONNECTION: called when a client connects to
369 * the server at network level; the connection is accepted but then
370 * passed to this callback to decide whether to hang up immediately
371 * or not, based on the client IP. @user contains the connection
372 * socket's descriptor. Return non-zero to terminate
373 * the connection before sending or receiving anything.
374 * Because this happens immediately after the network connection
375 * from the client, there's no websocket protocol selected yet so
376 * this callback is issued only to protocol 0.
378 * LWS_CALLBACK_FILTER_PROTOCOL_CONNECTION: called when the handshake has
379 * been received and parsed from the client, but the response is
380 * not sent yet. Return non-zero to disallow the connection.
381 * @user is a pointer to an array of struct lws_tokens, you can
382 * use the header enums lws_token_indexes from libwebsockets.h
383 * to check for and read the supported header presence and
384 * content before deciding to allow the handshake to proceed or
385 * to kill the connection.
387 * LWS_CALLBACK_OPENSSL_LOAD_EXTRA_CLIENT_VERIFY_CERTS: if configured for
388 * including OpenSSL support, this callback allows your user code
389 * to perform extra SSL_CTX_load_verify_locations() or similar
390 * calls to direct OpenSSL where to find certificates the client
391 * can use to confirm the remote server identity. @user is the
394 * LWS_CALLBACK_OPENSSL_LOAD_EXTRA_SERVER_VERIFY_CERTS: if configured for
395 * including OpenSSL support, this callback allows your user code
396 * to load extra certifcates into the server which allow it to
397 * verify the validity of certificates returned by clients. @user
398 * is the server's OpenSSL SSL_CTX*
400 * LWS_CALLBACK_OPENSSL_PERFORM_CLIENT_CERT_VERIFICATION: if the
401 * libwebsockets context was created with the option
402 * LWS_SERVER_OPTION_REQUIRE_VALID_OPENSSL_CLIENT_CERT, then this
403 * callback is generated during OpenSSL verification of the cert
404 * sent from the client. It is sent to protocol[0] callback as
405 * no protocol has been negotiated on the connection yet.
406 * Notice that the libwebsockets context and wsi are both NULL
407 * during this callback. See
408 * http://www.openssl.org/docs/ssl/SSL_CTX_set_verify.html
409 * to understand more detail about the OpenSSL callback that
410 * generates this libwebsockets callback and the meanings of the
411 * arguments passed. In this callback, @user is the x509_ctx,
412 * @in is the ssl pointer and @len is preverify_ok
413 * Notice that this callback maintains libwebsocket return
414 * conventions, return 0 to mean the cert is OK or 1 to fail it.
415 * This also means that if you don't handle this callback then
416 * the default callback action of returning 0 allows the client
419 * LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER: this callback happens
420 * when a client handshake is being compiled. @user is NULL,
421 * @in is a char **, it's pointing to a char * which holds the
422 * next location in the header buffer where you can add
423 * headers, and @len is the remaining space in the header buffer,
424 * which is typically some hundreds of bytes. So, to add a canned
425 * cookie, your handler code might look similar to:
427 * char **p = (char **)in;
432 * *p += sprintf(*p, "Cookie: a=b\x0d\x0a");
436 * Notice if you add anything, you just have to take care about
437 * the CRLF on the line you added. Obviously this callback is
438 * optional, if you don't handle it everything is fine.
440 * Notice the callback is coming to protocols[0] all the time,
441 * because there is no specific protocol handshook yet.
443 * LWS_CALLBACK_CONFIRM_EXTENSION_OKAY: When the server handshake code
444 * sees that it does support a requested extension, before
445 * accepting the extension by additing to the list sent back to
446 * the client it gives this callback just to check that it's okay
447 * to use that extension. It calls back to the requested protocol
448 * and with @in being the extension name, @len is 0 and @user is
449 * valid. Note though at this time the ESTABLISHED callback hasn't
450 * happened yet so if you initialize @user content there, @user
451 * content during this callback might not be useful for anything.
452 * Notice this callback comes to protocols[0].
454 * LWS_CALLBACK_CLIENT_CONFIRM_EXTENSION_SUPPORTED: When a client
455 * connection is being prepared to start a handshake to a server,
456 * each supported extension is checked with protocols[0] callback
457 * with this reason, giving the user code a chance to suppress the
458 * claim to support that extension by returning non-zero. If
459 * unhandled, by default 0 will be returned and the extension
460 * support included in the header to the server. Notice this
461 * callback comes to protocols[0].
463 * The next four reasons are optional and only need taking care of if you
464 * will be integrating libwebsockets sockets into an external polling
467 * LWS_CALLBACK_ADD_POLL_FD: libwebsocket deals with its poll() loop
468 * internally, but in the case you are integrating with another
469 * server you will need to have libwebsocket sockets share a
470 * polling array with the other server. This and the other
471 * POLL_FD related callbacks let you put your specialized
472 * poll array interface code in the callback for protocol 0, the
473 * first protocol you support, usually the HTTP protocol in the
474 * serving case. This callback happens when a socket needs to be
475 * added to the polling loop: @user contains the fd, and
476 * @len is the events bitmap (like, POLLIN). If you are using the
477 * internal polling loop (the "service" callback), you can just
478 * ignore these callbacks.
480 * LWS_CALLBACK_DEL_POLL_FD: This callback happens when a socket descriptor
481 * needs to be removed from an external polling array. @user is
482 * the socket desricptor. If you are using the internal polling
483 * loop, you can just ignore it.
485 * LWS_CALLBACK_SET_MODE_POLL_FD: This callback happens when libwebsockets
486 * wants to modify the events for the socket descriptor in @user.
487 * The handler should OR @len on to the events member of the pollfd
488 * struct for this socket descriptor. If you are using the
489 * internal polling loop, you can just ignore it.
491 * LWS_CALLBACK_CLEAR_MODE_POLL_FD: This callback occurs when libwebsockets
492 * wants to modify the events for the socket descriptor in @user.
493 * The handler should AND ~@len on to the events member of the
494 * pollfd struct for this socket descriptor. If you are using the
495 * internal polling loop, you can just ignore it.
497 LWS_EXTERN int callback(struct libwebsocket_context * context,
498 struct libwebsocket *wsi,
499 enum libwebsocket_callback_reasons reason, void *user,
500 void *in, size_t len);
502 typedef int (callback_function)(struct libwebsocket_context * context,
503 struct libwebsocket *wsi,
504 enum libwebsocket_callback_reasons reason, void *user,
505 void *in, size_t len);
509 * extension_callback_function() - Hooks to allow extensions to operate
510 * @context: Websockets context
511 * @ext: This extension
512 * @wsi: Opaque websocket instance pointer
513 * @reason: The reason for the call
514 * @user: Pointer to per-session user data allocated by library
515 * @in: Pointer used for some callback reasons
516 * @len: Length set for some callback reasons
518 * Each extension that is active on a particular connection receives
519 * callbacks during the connection lifetime to allow the extension to
520 * operate on websocket data and manage itself.
522 * Libwebsockets takes care of allocating and freeing "user" memory for
523 * each active extension on each connection. That is what is pointed to
524 * by the @user parameter.
526 * LWS_EXT_CALLBACK_CONSTRUCT: called when the server has decided to
527 * select this extension from the list provided by the client,
528 * just before the server will send back the handshake accepting
529 * the connection with this extension active. This gives the
530 * extension a chance to initialize its connection context found
533 * LWS_EXT_CALLBACK_CLIENT_CONSTRUCT: same as LWS_EXT_CALLBACK_CONSTRUCT
534 * but called when client is instantiating this extension. Some
535 * extensions will work the same on client and server side and then
536 * you can just merge handlers for both CONSTRUCTS.
538 * LWS_EXT_CALLBACK_DESTROY: called when the connection the extension was
539 * being used on is about to be closed and deallocated. It's the
540 * last chance for the extension to deallocate anything it has
541 * allocated in the user data (pointed to by @user) before the
542 * user data is deleted. This same callback is used whether you
543 * are in client or server instantiation context.
545 * LWS_EXT_CALLBACK_PACKET_RX_PREPARSE: when this extension was active on
546 * a connection, and a packet of data arrived at the connection,
547 * it is passed to this callback to give the extension a chance to
548 * change the data, eg, decompress it. @user is pointing to the
549 * extension's private connection context data, @in is pointing
550 * to an lws_tokens struct, it consists of a char * pointer called
551 * token, and an int called token_len. At entry, these are
552 * set to point to the received buffer and set to the content
553 * length. If the extension will grow the content, it should use
554 * a new buffer allocated in its private user context data and
555 * set the pointed-to lws_tokens members to point to its buffer.
557 * LWS_EXT_CALLBACK_PACKET_TX_PRESEND: this works the same way as
558 * LWS_EXT_CALLBACK_PACKET_RX_PREPARSE above, except it gives the
559 * extension a chance to change websocket data just before it will
560 * be sent out. Using the same lws_token pointer scheme in @in,
561 * the extension can change the buffer and the length to be
562 * transmitted how it likes. Again if it wants to grow the
563 * buffer safely, it should copy the data into its own buffer and
564 * set the lws_tokens token pointer to it.
566 LWS_EXTERN int extension_callback(struct libwebsocket_context * context,
567 struct libwebsocket_extension *ext,
568 struct libwebsocket *wsi,
569 enum libwebsocket_extension_callback_reasons reason, void *user,
570 void *in, size_t len);
572 typedef int (extension_callback_function)(struct libwebsocket_context * context,
573 struct libwebsocket_extension *ext,
574 struct libwebsocket *wsi,
575 enum libwebsocket_extension_callback_reasons reason, void *user,
576 void *in, size_t len);
579 * struct libwebsocket_protocols - List of protocols and handlers server
581 * @name: Protocol name that must match the one given in the client
582 * Javascript new WebSocket(url, 'protocol') name
583 * @callback: The service callback used for this protocol. It allows the
584 * service action for an entire protocol to be encapsulated in
585 * the protocol-specific callback
586 * @per_session_data_size: Each new connection using this protocol gets
587 * this much memory allocated on connection establishment and
588 * freed on connection takedown. A pointer to this per-connection
589 * allocation is passed into the callback in the 'user' parameter
590 * @owning_server: the server init call fills in this opaque pointer when
591 * registering this protocol with the server.
592 * @broadcast_socket_port: the server init call fills this in with the
593 * localhost port number used to forward broadcasts for this
595 * @broadcast_socket_user_fd: the server init call fills this in ... the main()
596 * process context can write to this socket to perform broadcasts
597 * (use the libwebsockets_broadcast() api to do this instead,
598 * it works from any process context)
599 * @protocol_index: which protocol we are starting from zero
601 * This structure represents one protocol supported by the server. An
602 * array of these structures is passed to libwebsocket_create_server()
603 * allows as many protocols as you like to be handled by one server.
606 struct libwebsocket_protocols {
608 callback_function *callback;
609 size_t per_session_data_size;
612 * below are filled in on server init and can be left uninitialized,
613 * no need for user to use them directly either
616 struct libwebsocket_context *owning_server;
617 int broadcast_socket_port;
618 int broadcast_socket_user_fd;
623 * struct libwebsocket_extension - An extension we know how to cope with
625 * @name: Formal extension name, eg, "deflate-stream"
626 * @callback: Service callback
627 * @per_session_data_size: Libwebsockets will auto-malloc this much
628 * memory for the use of the extension, a pointer
629 * to it comes in the @user callback parameter
630 * @per_context_private_data: Optional storage for this externsion that
631 * is per-context, so it can track stuff across
632 * all sessions, etc, if it wants
635 struct libwebsocket_extension {
637 extension_callback_function *callback;
638 size_t per_session_data_size;
639 void * per_context_private_data;
644 LWS_EXTERN struct libwebsocket_context *
645 libwebsocket_create_context(int port, const char * interf,
646 struct libwebsocket_protocols *protocols,
647 struct libwebsocket_extension *extensions,
648 const char *ssl_cert_filepath,
649 const char *ssl_private_key_filepath,
650 const char *ssl_ca_filepath,
652 unsigned int options, void *user);
655 libwebsocket_context_destroy(struct libwebsocket_context *context);
658 libwebsockets_fork_service_loop(struct libwebsocket_context *context);
661 libwebsocket_service(struct libwebsocket_context *context, int timeout_ms);
664 libwebsocket_service_fd(struct libwebsocket_context *context,
665 struct pollfd *pollfd);
668 libwebsocket_context_user(struct libwebsocket_context *context);
673 * When sending with websocket protocol (LWS_WRITE_TEXT or LWS_WRITE_BINARY)
674 * the send buffer has to have LWS_SEND_BUFFER_PRE_PADDING bytes valid BEFORE
675 * buf, and LWS_SEND_BUFFER_POST_PADDING bytes valid AFTER (buf + len).
677 * This allows us to add protocol info before and after the data, and send as
678 * one packet on the network without payload copying, for maximum efficiency.
680 * So for example you need this kind of code to use libwebsocket_write with a
683 * char buf[LWS_SEND_BUFFER_PRE_PADDING + 128 + LWS_SEND_BUFFER_POST_PADDING];
685 * // fill your part of the buffer... for example here it's all zeros
686 * memset(&buf[LWS_SEND_BUFFER_PRE_PADDING], 0, 128);
688 * libwebsocket_write(wsi, &buf[LWS_SEND_BUFFER_PRE_PADDING], 128);
690 * When sending LWS_WRITE_HTTP, there is no protocol addition and you can just
691 * use the whole buffer without taking care of the above.
695 * this is the frame nonce plus two header plus 8 length
696 * there's an additional two for mux extension per mux nesting level
697 * 2 byte prepend on close will already fit because control frames cannot use
698 * the big length style
701 #define LWS_SEND_BUFFER_PRE_PADDING (4 + 10 + (2 * MAX_MUX_RECURSION))
702 #define LWS_SEND_BUFFER_POST_PADDING 1
705 libwebsocket_write(struct libwebsocket *wsi, unsigned char *buf, size_t len,
706 enum libwebsocket_write_protocol protocol);
709 libwebsockets_serve_http_file(struct libwebsocket *wsi, const char *file,
710 const char *content_type);
712 /* notice - you need the pre- and post- padding allocation for buf below */
715 libwebsockets_broadcast(const struct libwebsocket_protocols *protocol,
716 unsigned char *buf, size_t len);
718 LWS_EXTERN const struct libwebsocket_protocols *
719 libwebsockets_get_protocol(struct libwebsocket *wsi);
722 libwebsocket_callback_on_writable(struct libwebsocket_context *context,
723 struct libwebsocket *wsi);
726 libwebsocket_callback_on_writable_all_protocol(
727 const struct libwebsocket_protocols *protocol);
730 libwebsocket_get_socket_fd(struct libwebsocket *wsi);
733 libwebsocket_is_final_fragment(struct libwebsocket *wsi);
736 libwebsocket_ensure_user_space(struct libwebsocket *wsi);
739 libwebsocket_rx_flow_control(struct libwebsocket *wsi, int enable);
742 libwebsockets_remaining_packet_payload(struct libwebsocket *wsi);
744 LWS_EXTERN struct libwebsocket *
745 libwebsocket_client_connect(struct libwebsocket_context *clients,
752 const char *protocol,
753 int ietf_version_or_minus_one);
755 LWS_EXTERN struct libwebsocket *
756 libwebsocket_client_connect_extended(struct libwebsocket_context *clients,
763 const char *protocol,
764 int ietf_version_or_minus_one,
767 LWS_EXTERN const char *
768 libwebsocket_canonical_hostname(struct libwebsocket_context *context);
772 libwebsockets_get_peer_addresses(int fd, char *name, int name_len,
773 char *rip, int rip_len);
776 libwebsockets_hangup_on_client(struct libwebsocket_context *context, int fd);
779 libwebsocket_close_and_free_session(struct libwebsocket_context *context,
780 struct libwebsocket *wsi, enum lws_close_status);
783 libwebsockets_get_random(struct libwebsocket_context *context,
787 lws_send_pipe_choked(struct libwebsocket *wsi);
789 LWS_EXTERN unsigned char *
790 libwebsockets_SHA1(const unsigned char *d, size_t n, unsigned char *md);
793 lws_b64_encode_string(const char *in, int in_len, char *out, int out_size);
796 lws_b64_decode_string(const char *in, char *out, int out_size);
798 LWS_EXTERN struct libwebsocket_extension libwebsocket_internal_extensions[];