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1 /*
2  * libwebsockets - small server side websockets and web server implementation
3  *
4  * Copyright (C) 2019 - 2020 Andy Green <andy@warmcat.com>
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to
8  * deal in the Software without restriction, including without limitation the
9  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10  * sell copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22  * IN THE SOFTWARE.
23  *
24  * included from libwebsockets.h
25  *
26  *
27  * Secure Streams is a *payload-only* client communication channel where all the
28  * details about the connection are held in a systemwide policy database and
29  * are keyed by the streamtype field... the user of the communication channel
30  * does not know or manage the choice of endpoint, tls CA, or even wire
31  * protocol.  The advantage is he then does not have any dependency on any of
32  * those and they can be changed just by changing the policy database without
33  * touching the code using the stream.
34  *
35  * There are two ways secure streams interfaces to user code:
36  *
37  * 1) [Linux / RTOS] the natural, smallest interface is to call back to user
38  *    code that only operates directly from the lws event loop thread context
39  *    (direct callbacks from lws_ss_t)
40  *
41  *    lws_thread( [user code] ---- lws )
42  *
43  * 2) [Linux] where the user code is in a different process and communicates
44  *    asynchronously via a proxy socket
45  *
46  *    user_process{ [user code] | shim | socket-}------ lws_process{ lws }
47  *
48  * In the second, IPC, case, all packets are prepended by one or more bytes
49  * indicating the packet type and serializing any associated data, known as
50  * Serialized Secure Streams or SSS.
51  *
52  * Serialized Secure Streams
53  * -------------------------
54  *
55  * On the transport, adjacent packets may be coalesced, that is, the original
56  * packet sizes are lost and two or more packets are combined.  For that reason
57  * the serialization format always contains a 1-byte type and then a 2-byte
58  * frame length.
59  *
60  * Client to proxy
61  *
62  * - Proxied connection setup
63  *
64  *   -  0: LWSSS_SER_TXPRE_STREAMTYPE
65  *   -  1: 2-byte MSB-first rest-of-frame length
66  *   -  3: 1-byte Client SSS protocol version (introduced in SSSv1)
67  *   -  4: 4-byte Client PID (introduced in SSSv1)
68  *   -  8: 4-byte MSB-first initial tx credit
69  *   - 12: the streamtype name with no NUL
70  *
71  * - Proxied tx
72  *
73  *   -  0: LWSSS_SER_TXPRE_TX_PAYLOAD
74  *   -  1: 2 byte MSB-first rest-of-frame length
75  *   -  3: 4-byte MSB-first flags
76  *   -  7: 4-byte MSB-first us between client requested write and wrote to proxy
77  *   - 11: 8-byte MSB-first us resolution unix time client wrote to proxy
78  *   - 19: payload
79  *
80  * - Proxied secure stream destroy
81  *
82  *   -  0: LWSSS_SER_TXPRE_DESTROYING
83  *   -  1: 00, 00
84  *
85  * - Proxied metadata - sent when one metadata item set clientside
86  *
87  *   -  0: LWSSS_SER_TXPRE_METADATA
88  *   -  1: 2-byte MSB-first rest-of-frame length
89  *   -  3: 1-byte metadata name length
90  *   -  4: metadata name
91  *   -  ...: metadata value (for rest of packet)
92  *
93  * - TX credit management - sent when using tx credit apis, cf METADATA
94  *
95  *   - 0: LWSSS_SER_TXPRE_TXCR_UPDATE
96  *   - 1: 2-byte MSB-first rest-of-frame length 00, 04
97  *   - 3: 4-byte additional tx credit adjust value
98  *
99  * - Stream timeout management - forwarded when user applying or cancelling t.o.
100  *
101  *   -  0: LWSSS_SER_TXPRE_TIMEOUT_UPDATE
102  *   -  1: 2-byte MSB-first rest-of-frame length 00, 04
103  *   -  3: 4-byte MSB-first unsigned 32-bit timeout, 0 = use policy, -1 = cancel
104  *
105  * - Passing up payload length hint
106  *
107  *   -  0: LWSSS_SER_TXPRE_PAYLOAD_LENGTH_HINT
108  *   -  1: 2-byte MSB-first rest-of-frame length 00, 04
109  *   -  3: 4-byte MSB-first unsigned 32-bit payload length hint
110  *
111  * Proxy to client
112  *
113  * - Proxied connection setup result
114  *
115  *   -  0: LWSSS_SER_RXPRE_CREATE_RESULT
116  *   -  1: 2 byte MSB-first rest-of-frame length (usually 00, 03)
117  *   -  3: 1 byte result, 0 = success.  On failure, proxy will close connection.
118  *   -  4: 4 byte client dsh allocation recommended for stream type, from policy
119  *         (introduced in SSSv1)
120  *   -  8: 2 byte MSB-first initial tx credit
121  *   - 10: if present, comma-sep list of rideshare types from policy
122  *
123  * - Proxied rx
124  *
125  *   -  0: LWSSS_SER_RXPRE_RX_PAYLOAD
126  *   -  1: 2 byte MSB-first rest-of-frame length
127  *   -  3: 4-byte MSB-first flags
128  *   -  7: 4-byte MSB-first us between inbound read and wrote to client
129  *   - 11: 8-byte MSB-first us resolution unix time proxy wrote to client
130  *   - 17: (rideshare name len + rideshare name if flags & LWSSS_FLAG_RIDESHARE)
131  *          payload
132  *
133  * - Proxied tx credit
134  *
135  *   -  0: LWSSS_SER_RXPRE_TXCR_UPDATE
136  *   -  1: 00, 04
137  *   -  3: 4-byte MSB-first addition tx credit bytes
138  *
139  * - Proxied rx metadata
140  *
141  *   -  0: LWSSS_SER_RXPRE_METADATA
142  *   -  1: 2-byte MSB-first rest-of-frame length
143  *   -  3: 1-byte metadata name length
144  *   -  4: metadata name
145  *   -  ...: metadata value (for rest of packet)
146  *
147  * - Proxied state (8 or 11 byte packet)
148  *
149  *   -  0: LWSSS_SER_RXPRE_CONNSTATE
150  *   -  1: 00, 05 if state < 256, else 00, 08
151  *   -  3: 1 byte state index if state < 256, else 4-byte MSB-first state index
152  *   -  4 or 7: 4-byte MSB-first ordinal
153  *
154  * - Proxied performance information
155  *
156  *   -  0: LWSSS_SER_RXPRE_PERF
157  *   -  1: 2-byte MSB-first rest-of-frame length
158  *   -  3: ... performance JSON (for rest of packet)
159  *
160  * Proxied tx may be read by the proxy but rejected due to lack of buffer space
161  * at the proxy.  For that reason, tx must be held at the sender until it has
162  * been acknowledged or denied.
163  *
164  * Sinks
165  * -----
166  *
167  * Sinks are logical "servers", you can register as a sink for a particular
168  * streamtype by using the lws_ss_create() api with ssi->register_sink set to 1.
169  *
170  * For directly fulfilled Secure Streams, new streams of that streamtype bind
171  * to the rx, tx and state handlers given when it was registered.
172  *
173  *  - When new streams are created the registered sink handler for (*state) is
174  *    called with event LWSSSCS_SINK_JOIN and the new client stream handle in
175  *    the h_src parameter.
176  *
177  *  - When the client stream sends something to the sink, it calls the sink's
178  *    (*rx) with the client stream's
179  */
180 
181 /** \defgroup secstr Secure Streams
182 * ##Secure Streams
183 *
184 * Secure Streams related apis
185 */
186 ///@{
187 
188 #define LWS_SS_MTU 1540
189 
190 struct lws_ss_handle;
191 typedef uint32_t lws_ss_tx_ordinal_t;
192 
193 /*
194  * connection state events
195  *
196  * If you add states, take care about the state names and state transition
197  * validity enforcement tables too
198  */
199 typedef enum {
200 	/* zero means unset */
201 	LWSSSCS_CREATING		= 1,
202 	LWSSSCS_DISCONNECTED,
203 	LWSSSCS_UNREACHABLE,		/* oridinal arg = 1 = caused by dns
204 					 * server reachability failure */
205 	LWSSSCS_AUTH_FAILED,
206 	LWSSSCS_CONNECTED,
207 	LWSSSCS_CONNECTING,
208 	LWSSSCS_DESTROYING,
209 	LWSSSCS_POLL,
210 	LWSSSCS_ALL_RETRIES_FAILED,	/* all retries in bo policy failed */
211 	LWSSSCS_QOS_ACK_REMOTE,		/* remote peer received and acked tx */
212 	LWSSSCS_QOS_NACK_REMOTE,
213 	LWSSSCS_QOS_ACK_LOCAL,		/* local proxy accepted our tx */
214 	LWSSSCS_QOS_NACK_LOCAL,		/* local proxy refused our tx */
215 	LWSSSCS_TIMEOUT,		/* optional timeout timer fired */
216 
217 	LWSSSCS_SERVER_TXN,
218 	LWSSSCS_SERVER_UPGRADE,		/* the server protocol upgraded */
219 
220 	LWSSSCS_EVENT_WAIT_CANCELLED, /* somebody called lws_cancel_service */
221 
222 	LWSSSCS_UPSTREAM_LINK_RETRY,	/* if we are being proxied over some
223 					 * intermediate link, this transient
224 					 * state may be sent to indicate we are
225 					 * waiting to establish that link before
226 					 * creation can proceed.. ack is the
227 					 * number of ms we have been trying */
228 
229 	LWSSSCS_SINK_JOIN,		/* sinks get this when a new source
230 					 * stream joins the sink */
231 	LWSSSCS_SINK_PART,		/* sinks get this when a new source
232 					 * stream leaves the sink */
233 
234 	LWSSSCS_USER_BASE = 1000
235 } lws_ss_constate_t;
236 
237 enum {
238 	LWSSS_FLAG_SOM						= (1 << 0),
239 	/* payload contains the start of new message */
240 	LWSSS_FLAG_EOM						= (1 << 1),
241 	/* payload contains the end of message */
242 	LWSSS_FLAG_POLL						= (1 << 2),
243 	/* Not a real transmit... poll for rx if protocol needs it */
244 	LWSSS_FLAG_RELATED_START				= (1 << 3),
245 	/* Appears in a zero-length message indicating a message group of zero
246 	 * or more messages is now starting. */
247 	LWSSS_FLAG_RELATED_END					= (1 << 4),
248 	/* Appears in a zero-length message indicating a message group of zero
249 	 * or more messages has now finished. */
250 	LWSSS_FLAG_RIDESHARE					= (1 << 5),
251 	/* Serialized payload starts with non-default rideshare name length and
252 	 * name string without NUL, then payload */
253 	LWSSS_FLAG_PERF_JSON					= (1 << 6),
254 	/* This RX is JSON performance data, only on streams with "perf" flag
255 	 * set */
256 
257 	/*
258 	 * In the case the secure stream is proxied across a process or thread
259 	 * boundary, eg by proxying through a socket for IPC, metadata must be
260 	 * carried in-band.  A byte is prepended to each rx payload to
261 	 * differentiate what it is.
262 	 *
263 	 * Secure streams where the user is called back directly does not need
264 	 * any of this and only pure payloads are passed.
265 	 *
266 	 * rx (received by client) prepends for proxied connections
267 	 */
268 
269 	LWSSS_SER_RXPRE_RX_PAYLOAD				= 0x55,
270 	LWSSS_SER_RXPRE_CREATE_RESULT,
271 	LWSSS_SER_RXPRE_CONNSTATE,
272 	LWSSS_SER_RXPRE_TXCR_UPDATE,
273 	LWSSS_SER_RXPRE_METADATA,
274 	LWSSS_SER_RXPRE_TLSNEG_ENCLAVE_SIGN,
275 	LWSSS_SER_RXPRE_PERF,
276 
277 	/* tx (send by client) prepends for proxied connections */
278 
279 	LWSSS_SER_TXPRE_STREAMTYPE				= 0xaa,
280 	LWSSS_SER_TXPRE_ONWARD_CONNECT,
281 	LWSSS_SER_TXPRE_DESTROYING,
282 	LWSSS_SER_TXPRE_TX_PAYLOAD,
283 	LWSSS_SER_TXPRE_METADATA,
284 	LWSSS_SER_TXPRE_TXCR_UPDATE,
285 	LWSSS_SER_TXPRE_TIMEOUT_UPDATE,
286 	LWSSS_SER_TXPRE_PAYLOAD_LENGTH_HINT,
287 	LWSSS_SER_TXPRE_TLSNEG_ENCLAVE_SIGNED,
288 };
289 
290 typedef enum {
291 	LPCSPROX_WAIT_INITIAL_TX = 1, /* after connect, must send streamtype */
292 	LPCSPROX_REPORTING_FAIL, /* stream creation failed, wait to to tell */
293 	LPCSPROX_REPORTING_OK, /* stream creation succeeded, wait to to tell */
294 	LPCSPROX_OPERATIONAL, /* ready for payloads */
295 	LPCSPROX_DESTROYED,
296 
297 	LPCSCLI_SENDING_INITIAL_TX,  /* after connect, must send streamtype */
298 	LPCSCLI_WAITING_CREATE_RESULT,   /* wait to hear if proxy ss create OK */
299 	LPCSCLI_LOCAL_CONNECTED,	      /* we are in touch with the proxy */
300 	LPCSCLI_ONWARD_CONNECT,	      /* request onward ss connection */
301 	LPCSCLI_OPERATIONAL, /* ready for payloads */
302 
303 } lws_ss_conn_states_t;
304 
305 /*
306  * Returns from state() callback can tell the caller what the user code
307  * wants to do
308  */
309 
310 typedef enum lws_ss_state_return {
311 	LWSSSSRET_TX_DONT_SEND		=  1, /* (*tx) only, or failure */
312 
313 	LWSSSSRET_OK			=  0, /* no error */
314 	LWSSSSRET_DISCONNECT_ME		= -1, /* caller should disconnect us */
315 	LWSSSSRET_DESTROY_ME		= -2, /* caller should destroy us */
316 } lws_ss_state_return_t;
317 
318 /**
319  * lws_ss_info_t: information about stream to be created
320  *
321  * Prepare this struct with information about what the stream type is and how
322  * the stream should interface with your code, and pass it to lws_ss_create()
323  * to create the requested stream.
324  */
325 
326 enum {
327 	LWSSSINFLAGS_REGISTER_SINK			=	(1 << 0),
328 	/**< If set, we're not creating a specific stream, but registering
329 	 * ourselves as the "sink" for .streamtype.  It's analogous to saying
330 	 * we want to be the many-to-one "server" for .streamtype; when other
331 	 * streams are created with that streamtype, they should be forwarded
332 	 * to this stream owner, where they join and part from the sink via
333 	 * (*state) LWSSSCS_SINK_JOIN / _PART events, the new client handle
334 	 * being provided in the h_src parameter.
335 	 */
336 	LWSSSINFLAGS_PROXIED				=	(1 << 1),
337 	/**< Set if the stream is being created as a stand-in at the proxy */
338 	LWSSSINFLAGS_SERVER				=	(1 << 2),
339 	/**< Set on the server object copy of the ssi / info to indicate that
340 	 * stream creation using this ssi is for Accepted connections belonging
341 	 * to a server */
342 	LWSSSINFLAGS_ACCEPTED				=	(1 << 3),
343 	/**< Set on the accepted object copy of the ssi / info to indicate that
344 	 * we are an accepted connection from a server's listening socket */
345 };
346 
347 typedef lws_ss_state_return_t (*lws_sscb_rx)(void *userobj, const uint8_t *buf,
348 					     size_t len, int flags);
349 typedef lws_ss_state_return_t (*lws_sscb_tx)(void *userobj,
350 					     lws_ss_tx_ordinal_t ord,
351 					     uint8_t *buf, size_t *len,
352 					     int *flags);
353 typedef lws_ss_state_return_t (*lws_sscb_state)(void *userobj, void *h_src,
354 						lws_ss_constate_t state,
355 						lws_ss_tx_ordinal_t ack);
356 
357 #if defined(LWS_WITH_SECURE_STREAMS_BUFFER_DUMP)
358 typedef void (*lws_ss_buffer_dump_cb)(void *userobj, const uint8_t *buf,
359 		size_t len, int done);
360 #endif
361 
362 struct lws_ss_policy;
363 
364 typedef struct lws_ss_info {
365 	const char *streamtype; /**< type of stream we want to create */
366 	size_t	    user_alloc; /**< size of user allocation */
367 	size_t	    handle_offset; /**< offset of handle stg in user_alloc type,
368 				    set to offsetof(mytype, my_handle_member) */
369 	size_t	    opaque_user_data_offset;
370 	/**< offset of opaque user data ptr in user_alloc type, set to
371 	     offsetof(mytype, opaque_ud_member) */
372 
373 #if defined(LWS_WITH_SECURE_STREAMS_CPP)
374 	const struct lws_ss_policy	*policy;
375 	/**< Normally NULL, or a locally-generated policy to apply to this
376 	 * connection instead of a named streamtype */
377 #endif
378 
379 #if defined(LWS_WITH_SYS_FAULT_INJECTION)
380 	lws_fi_ctx_t				fic;
381 	/**< Attach external Fault Injection context to the stream, hierarchy
382 	 * is ss->context */
383 #endif
384 
385 	lws_sscb_rx rx;
386 	/**< callback with rx payload for this stream */
387 	lws_sscb_tx tx;
388 	/**< callback to send payload on this stream... 0 = send as set in
389 	 * len and flags, 1 = do not send anything (ie, not even 0 len frame) */
390 	lws_sscb_state state;
391 	/**< advisory cb about state of stream and QoS status if applicable...
392 	 * h_src is only used with sinks and LWSSSCS_SINK_JOIN/_PART events.
393 	 * Return nonzero to indicate you want to destroy the stream. */
394 #if defined(LWS_WITH_SECURE_STREAMS_BUFFER_DUMP)
395 	lws_ss_buffer_dump_cb dump;
396 	/**< cb to record needed protocol buffer data*/
397 #endif
398 	int	    manual_initial_tx_credit;
399 	/**< 0 = manage any tx credit automatically, nonzero explicitly sets the
400 	 * peer stream to have the given amount of tx credit, if the protocol
401 	 * can support it.
402 	 *
403 	 * In the special case of _lws_smd streamtype, this is used to indicate
404 	 * the connection's rx class mask.
405 	 * */
406 	uint32_t	client_pid;
407 	/**< used in proxy / serialization case to hold the client pid this
408 	 * proxied connection is to be tagged with
409 	 */
410 	uint8_t		flags;
411 	uint8_t		sss_protocol_version;
412 	/**< used in proxy / serialization case to hold the SS serialization
413 	 * protocol level to use with this peer... clients automatically request
414 	 * the most recent version they were built with
415 	 * (LWS_SSS_CLIENT_PROTOCOL_VERSION) and the proxy stores the requested
416 	 * version in here
417 	 */
418 
419 } lws_ss_info_t;
420 
421 /**
422  * lws_ss_create() - Create secure stream
423  *
424  * \param context: the lws context to create this inside
425  * \param tsi: service thread index to create on (normally 0)
426  * \param ssi: pointer to lws_ss_info_t filled in with info about desired stream
427  * \param opaque_user_data: opaque data to set in the stream's user object
428  * \param ppss: pointer to secure stream handle pointer set on exit
429  * \param ppayload_fmt: NULL or pointer to a string ptr to take payload format
430  *			name from the policy
431  *
432  * Requests a new secure stream described by \p ssi be created.  If successful,
433  * the stream is created, its state callback called with LWSSSCS_CREATING, \p *ppss
434  * is set to point to the handle, and it returns 0.  If it failed, it returns
435  * nonzero.
436  *
437  * Along with the opaque stream object, streams overallocate
438  *
439  * 1) a user data struct whose size is set in ssi
440  * 2) nauth plugin instantiation data (size set in the plugin struct)
441  * 3) sauth plugin instantiation data (size set in the plugin struct)
442  * 4) space for a copy of the stream type name
443  *
444  * The user data struct is initialized to all zeros, then the .handle_offset and
445  * .opaque_user_data_offset fields of the ssi are used to prepare the user data
446  * struct with the ss handle that was created, and a copy of the
447  * opaque_user_data pointer given as an argument.
448  *
449  * If you want to set up the stream with specific information, point to it in
450  * opaque_user_data and use the copy of that pointer in your user data member
451  * for it starting from the LWSSSCS_CREATING state call.
452  *
453  * Since different endpoints chosen by the policy may require different payload
454  * formats, \p ppayload_fmt is set to point to the name of the needed payload
455  * format from the policy database if non-NULL.
456  */
457 LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT
458 lws_ss_create(struct lws_context *context, int tsi, const lws_ss_info_t *ssi,
459 	      void *opaque_user_data, struct lws_ss_handle **ppss,
460 	      struct lws_sequencer *seq_owner, const char **ppayload_fmt);
461 
462 /**
463  * lws_ss_destroy() - Destroy secure stream
464  *
465  * \param ppss: pointer to lws_ss_t pointer to be destroyed
466  *
467  * Destroys the lws_ss_t pointed to by \p *ppss, and sets \p *ppss to NULL.
468  */
469 LWS_VISIBLE LWS_EXTERN void
470 lws_ss_destroy(struct lws_ss_handle **ppss);
471 
472 /**
473  * lws_ss_request_tx() - Schedule stream for tx
474  *
475  * \param pss: pointer to lws_ss_t representing stream that wants to transmit
476  *
477  * Schedules a write on the stream represented by \p pss.  When it's possible to
478  * write on this stream, the \p *tx callback will occur with an empty buffer for
479  * the stream owner to fill in.
480  *
481  * Returns 0 or LWSSSSRET_DESTROY_ME
482  */
483 LWS_VISIBLE LWS_EXTERN lws_ss_state_return_t LWS_WARN_UNUSED_RESULT
484 lws_ss_request_tx(struct lws_ss_handle *pss);
485 
486 /**
487  * lws_ss_request_tx() - Schedule stream for tx
488  *
489  * \param pss: pointer to lws_ss_t representing stream that wants to transmit
490  * \param len: the length of the write in bytes
491  *
492  * Schedules a write on the stream represented by \p pss.  When it's possible to
493  * write on this stream, the \p *tx callback will occur with an empty buffer for
494  * the stream owner to fill in.
495  *
496  * This api variant should be used when it's possible the payload will go out
497  * over h1 with x-web-form-urlencoded or similar Content-Type.
498  */
499 LWS_VISIBLE LWS_EXTERN lws_ss_state_return_t LWS_WARN_UNUSED_RESULT
500 lws_ss_request_tx_len(struct lws_ss_handle *pss, unsigned long len);
501 
502 /**
503  * lws_ss_client_connect() - Attempt the client connect
504  *
505  * \param h: secure streams handle
506  *
507  * Starts the connection process for the secure stream.
508  *
509  * Can return any of the lws_ss_state_return_t values depending on user
510  * state callback returns.
511  *
512  * LWSSSSRET_OK means the connection is ongoing.
513  *
514  */
515 LWS_VISIBLE LWS_EXTERN lws_ss_state_return_t LWS_WARN_UNUSED_RESULT
516 lws_ss_client_connect(struct lws_ss_handle *h);
517 
518 /**
519  * lws_ss_get_sequencer() - Return parent sequencer pointer if any
520  *
521  * \param h: secure streams handle
522  *
523  * Returns NULL if the secure stream is not associated with a sequencer.
524  * Otherwise returns a pointer to the owning sequencer.  You can use this to
525  * identify which sequencer to direct messages to, from the secure stream
526  * callback.
527  */
528 LWS_VISIBLE LWS_EXTERN struct lws_sequencer *
529 lws_ss_get_sequencer(struct lws_ss_handle *h);
530 
531 /**
532  * lws_ss_proxy_create() - Start a unix domain socket proxy for Secure Streams
533  *
534  * \param context: lws_context
535  * \param bind: if port is 0, unix domain path with leading @ for abstract.
536  *		if port nonzero, NULL, or network interface to bind listen to
537  * \param port: tcp port to listen on
538  *
539  * Creates a vhost that listens either on an abstract namespace unix domain
540  * socket (port = 0) or a tcp listen socket (port nonzero).  If bind is NULL
541  * and port is 0, the abstract unix domain socket defaults to "proxy.ss.lws".
542  *
543  * Client connections to this proxy to Secure Streams are fulfilled using the
544  * policy local to the proxy and the data passed between the client and the
545  * proxy using serialized Secure Streams protocol.
546  */
547 LWS_VISIBLE LWS_EXTERN int
548 lws_ss_proxy_create(struct lws_context *context, const char *bind, int port);
549 
550 /**
551  * lws_ss_state_name() - convenience helper to get a printable conn state name
552  *
553  * \param state: the connection state index
554  *
555  * Returns a printable name for the connection state index passed in.
556  */
557 LWS_VISIBLE LWS_EXTERN const char *
558 lws_ss_state_name(int state);
559 
560 /**
561  * lws_ss_get_context() - convenience helper to recover the lws context
562  *
563  * \param h: secure streams handle
564  *
565  * Returns the lws context.  Dispenses with the need to pass a copy of it into
566  * your secure streams handler.
567  */
568 LWS_VISIBLE LWS_EXTERN struct lws_context *
569 lws_ss_get_context(struct lws_ss_handle *h);
570 
571 #define LWSSS_TIMEOUT_FROM_POLICY				0
572 
573 /**
574  * lws_ss_start_timeout() - start or restart the timeout on the stream
575  *
576  * \param h: secure streams handle
577  * \param timeout_ms: LWSSS_TIMEOUT_FROM_POLICY for policy value, else use timeout_ms
578  *
579  * Starts or restarts the stream's own timeout timer.  If the specified time
580  * passes without lws_ss_cancel_timeout() being called on the stream, then the
581  * stream state callback receives LWSSSCS_TIMEOUT
582  *
583  * The process being protected by the timeout is up to the user code, it may be
584  * arbitrarily long and cross multiple protocol transactions or involve other
585  * streams.  It's up to the user to decide when to start and when / if to cancel
586  * the stream timeout.
587  */
588 LWS_VISIBLE LWS_EXTERN void
589 lws_ss_start_timeout(struct lws_ss_handle *h, unsigned int timeout_ms);
590 
591 /**
592  * lws_ss_cancel_timeout() - remove any timeout on the stream
593  *
594  * \param h: secure streams handle
595  *
596  * Disable any timeout that was applied to the stream by lws_ss_start_timeout().
597  */
598 LWS_VISIBLE LWS_EXTERN void
599 lws_ss_cancel_timeout(struct lws_ss_handle *h);
600 
601 /**
602  * lws_ss_to_user_object() - convenience helper to get user object from handle
603  *
604  * \param h: secure streams handle
605  *
606  * Returns the user allocation related to the handle.  Normally you won't need
607  * this since it's available in the rx, tx and state callbacks as "userdata"
608  * already.
609  */
610 LWS_VISIBLE LWS_EXTERN void *
611 lws_ss_to_user_object(struct lws_ss_handle *h);
612 
613 /**
614  * lws_ss_rideshare() - find the current streamtype when types rideshare
615  *
616  * \param h: the stream handle
617  *
618  * Under some conditions, the payloads may be structured using protocol-
619  * specific formatting, eg, http multipart mime.  It's possible to map the
620  * logical partitions in the payload to different stream types using
621  * the policy "rideshare" feature.
622  *
623  * This api lets the callback code find out which rideshare stream type the
624  * current payload chunk belongs to.
625  */
626 LWS_VISIBLE LWS_EXTERN const char *
627 lws_ss_rideshare(struct lws_ss_handle *h);
628 
629 
630 /**
631  * lws_ss_set_metadata() - allow user to bind external data to defined ss metadata
632  *
633  * \param h: secure streams handle
634  * \param name: metadata name from the policy
635  * \param value: pointer to user-managed data to bind to name
636  * \param len: length of the user-managed data in value
637  *
638  * Binds user-managed data to the named metadata item from the ss policy.
639  * If present, the metadata item is handled in a protocol-specific way using
640  * the associated policy information.  For example, in the policy
641  *
642  *  	"\"metadata\":"		"["
643  *		"{\"uptag\":"  "\"X-Upload-Tag:\"},"
644  *		"{\"ctype\":"  "\"Content-Type:\"},"
645  *		"{\"xctype\":" "\"\"}"
646  *	"],"
647  *
648  * when the policy is using h1 is interpreted to add h1 headers of the given
649  * name with the value of the metadata on the left.
650  *
651  * Return 0 if OK or nonzero if, eg, metadata name does not exist on the
652  * streamtype.  You must check the result of this, eg, transient OOM can cause
653  * these to fail and you should retry later.
654  */
655 LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT
656 lws_ss_set_metadata(struct lws_ss_handle *h, const char *name,
657 		    const void *value, size_t len);
658 
659 /**
660  * lws_ss_alloc_set_metadata() - copy data and bind to ss metadata
661  *
662  * \param h: secure streams handle
663  * \param name: metadata name from the policy
664  * \param value: pointer to user-managed data to bind to name
665  * \param len: length of the user-managed data in value
666  *
667  * Same as lws_ss_set_metadata(), but allocates a heap buffer for the data
668  * first and takes a copy of it, so the original can go out of scope
669  * immediately after.
670  */
671 LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT
672 lws_ss_alloc_set_metadata(struct lws_ss_handle *h, const char *name,
673 			  const void *value, size_t len);
674 
675 /**
676  * lws_ss_get_metadata() - get current value of stream metadata item
677  *
678  * \param h: secure streams handle
679  * \param name: metadata name from the policy
680  * \param value: pointer to pointer to be set to point at the value
681  * \param len: pointer to size_t to set to the length of the value
682  *
683  * Binds user-managed data to the named metadata item from the ss policy.
684  * If present, the metadata item is handled in a protocol-specific way using
685  * the associated policy information.  For example, in the policy
686  *
687  *  	"\"metadata\":"		"["
688  *		"{\"uptag\":"  "\"X-Upload-Tag:\"},"
689  *		"{\"ctype\":"  "\"Content-Type:\"},"
690  *		"{\"xctype\":" "\"\"}"
691  *	"],"
692  *
693  * when the policy is using h1 is interpreted to add h1 headers of the given
694  * name with the value of the metadata on the left.
695  *
696  * Return 0 if \p *value and \p *len set OK, or nonzero if, eg, metadata \p name does
697  * not exist on the streamtype.
698  *
699  * The pointed-to values may only exist until the next time around the event
700  * loop.
701  */
702 LWS_VISIBLE LWS_EXTERN int
703 lws_ss_get_metadata(struct lws_ss_handle *h, const char *name,
704 		    const void **value, size_t *len);
705 
706 /**
707  * lws_ss_server_ack() - indicate how we feel about what the server has sent
708  *
709  * \param h: ss handle of accepted connection
710  * \param nack: 0 means we are OK with it, else some problem
711  *
712  * For SERVER secure streams
713  *
714  * Depending on the protocol, the server sending us something may be
715  * transactional, ie, built into it sending something is the idea we will
716  * respond somehow out-of-band; HTTP is like this with, eg, 200 response code.
717  *
718  * Calling this with nack=0 indicates that when we later respond, we want to
719  * acknowledge the transaction (eg, it means a 200 if http underneath), if
720  * nonzero that the transaction should act like it failed.
721  *
722  * If the underlying protocol doesn't understand transactions (eg, ws) then this
723  * has no effect either way.
724  */
725 LWS_VISIBLE LWS_EXTERN void
726 lws_ss_server_ack(struct lws_ss_handle *h, int nack);
727 
728 typedef void (*lws_sssfec_cb)(struct lws_ss_handle *h, void *arg);
729 
730 /**
731  * lws_ss_server_foreach_client() - callback for each live client connected to server
732  *
733  * \param h: server ss handle
734  * \param cb: the callback
735  * \param arg: arg passed to callback
736  *
737  * For SERVER secure streams
738  *
739  * Call the callback \p cb once for each client ss connected to the server,
740  * passing \p arg as an additional callback argument each time.
741  */
742 LWS_VISIBLE LWS_EXTERN void
743 lws_ss_server_foreach_client(struct lws_ss_handle *h, lws_sssfec_cb cb,
744 			     void *arg);
745 
746 /**
747  * lws_ss_change_handlers() - helper for dynamically changing stream handlers
748  *
749  * \param h: ss handle
750  * \param rx: the new RX handler
751  * \param tx: the new TX handler
752  * \param state: the new state handler
753  *
754  * Handlers set to NULL are left unchanged.
755  *
756  * This works on any handle, client or server and takes effect immediately.
757  *
758  * Depending on circumstances this may be helpful when
759  *
760  * a) a server stream undergoes an LWSSSCS_SERVER_UPGRADE (as in http -> ws) and
761  * the payloads in the new protocol have a different purpose that is best
762  * handled in their own rx and tx callbacks, and
763  *
764  * b) you may want to serve several different, possibly large things based on
765  * what was requested.  Setting a customized handler allows clean encapsulation
766  * of the different serving strategies.
767  *
768  * If the stream is long-lived, like ws, you should set the changed handler back
769  * to the default when the transaction wanting it is completed.
770  */
771 LWS_VISIBLE LWS_EXTERN void
772 lws_ss_change_handlers(struct lws_ss_handle *h, lws_sscb_rx rx, lws_sscb_tx tx,
773 		       lws_sscb_state state);
774 
775 /**
776  * lws_ss_add_peer_tx_credit() - allow peer to transmit more to us
777  *
778  * \param h: secure streams handle
779  * \param add: additional tx credit (signed)
780  *
781  * Indicate to remote peer that we can accept \p add bytes more payload being
782  * sent to us.
783  */
784 LWS_VISIBLE LWS_EXTERN int
785 lws_ss_add_peer_tx_credit(struct lws_ss_handle *h, int32_t add);
786 
787 /**
788  * lws_ss_get_est_peer_tx_credit() - get our current estimate of peer's tx credit
789  *
790  * \param h: secure streams handle
791  *
792  * Based on what credit we gave it, and what we have received, report our
793  * estimate of peer's tx credit usable to transmit to us.  This may be outdated
794  * in that some or all of its credit may already have been expended by sending
795  * stuff to us that is in flight already.
796  */
797 LWS_VISIBLE LWS_EXTERN int
798 lws_ss_get_est_peer_tx_credit(struct lws_ss_handle *h);
799 
800 LWS_VISIBLE LWS_EXTERN const char *
801 lws_ss_tag(struct lws_ss_handle *h);
802 
803 
804 #if defined(LWS_WITH_SECURE_STREAMS_AUTH_SIGV4)
805 /**
806  * lws_ss_sigv4_set_aws_key() - set aws credential into system blob
807  *
808  * \param context: lws_context
809  * \param idx:     the system blob index specified in the policy, currently
810  *                  up to 4 blobs.
811  * \param keyid:   aws access keyid
812  * \param key:     aws access key
813  *
814  * Return 0 if OK or nonzero if e.g. idx is invalid; system blob heap appending
815  * fails.
816  */
817 
818 LWS_VISIBLE LWS_EXTERN int
819 lws_ss_sigv4_set_aws_key(struct lws_context* context, uint8_t idx,
820 		                const char * keyid, const char * key);
821 
822 /**
823  * lws_aws_filesystem_credentials_helper() - read aws credentials from file
824  *
825  * \param path: path to read, ~ at start is converted to $HOME contents if any
826  * \param kid: eg, "aws_access_key_id"
827  * \param ak: eg, "aws_secret_access_key"
828  * \param aws_keyid: pointer to pointer for allocated keyid from credentials file
829  * \param aws_key: pointer to pointer for allocated key from credentials file
830  *
831  * Return 0 if both *aws_keyid and *aws_key allocated from the config file, else
832  * nonzero, and neither *aws_keyid or *aws_key are allocated.
833  *
834  * If *aws_keyid and *aws_key are set, it's the user's responsibility to
835  * free() them when they are no longer needed.
836  */
837 
838 LWS_VISIBLE LWS_EXTERN int
839 lws_aws_filesystem_credentials_helper(const char *path, const char *kid,
840 				      const char *ak, char **aws_keyid,
841 				      char **aws_key);
842 
843 #endif
844 
845 ///@}
846 
847