1/*
2 * libwebsockets - small server side websockets and web server implementation
3 *
4 * Copyright (C) 2010 - 2021 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
25/*! \defgroup client Client related functions
26 * ##Client releated functions
27 * \ingroup lwsapi
28 *
29 * */
30///@{
31
32/** enum lws_client_connect_ssl_connection_flags - flags that may be used
33 * with struct lws_client_connect_info ssl_connection member to control if
34 * and how SSL checks apply to the client connection being created
35 */
36
37enum lws_client_connect_ssl_connection_flags {
38 LCCSCF_USE_SSL = (1 << 0),
39 LCCSCF_ALLOW_SELFSIGNED = (1 << 1),
40 LCCSCF_SKIP_SERVER_CERT_HOSTNAME_CHECK = (1 << 2),
41 LCCSCF_ALLOW_EXPIRED = (1 << 3),
42 LCCSCF_ALLOW_INSECURE = (1 << 4),
43 LCCSCF_H2_QUIRK_NGHTTP2_END_STREAM = (1 << 5),
44 LCCSCF_H2_QUIRK_OVERFLOWS_TXCR = (1 << 6),
45 LCCSCF_H2_AUTH_BEARER = (1 << 7),
46 LCCSCF_H2_HEXIFY_AUTH_TOKEN = (1 << 8),
47 LCCSCF_H2_MANUAL_RXFLOW = (1 << 9),
48 LCCSCF_HTTP_MULTIPART_MIME = (1 << 10),
49 LCCSCF_HTTP_X_WWW_FORM_URLENCODED = (1 << 11),
50 LCCSCF_HTTP_NO_FOLLOW_REDIRECT = (1 << 12),
51
52 LCCSCF_PIPELINE = (1 << 16),
53 /**< Serialize / pipeline multiple client connections
54 * on a single connection where possible.
55 *
56 * HTTP/1.0: possible if Keep-Alive: yes sent by server
57 * HTTP/1.1: always possible... uses pipelining
58 * HTTP/2: always possible... uses parallel streams
59 */
60 LCCSCF_MUXABLE_STREAM = (1 << 17),
61 LCCSCF_H2_PRIOR_KNOWLEDGE = (1 << 18),
62 LCCSCF_WAKE_SUSPEND__VALIDITY = (1 << 19),
63 /* our validity checks are important enough to wake from suspend */
64 LCCSCF_PRIORITIZE_READS = (1 << 20),
65 /**<
66 * Normally lws balances reads and writes on all connections, so both
67 * are possible even on busy connections, and we go around the event
68 * loop more often to facilitate that, even if there is pending data.
69 *
70 * This flag indicates that you want to handle any pending reads on this
71 * connection without yielding the service loop for anything else. This
72 * means you may block other connection processing in favour of incoming
73 * data processing on this one if it receives back to back incoming rx.
74 */
75 LCCSCF_SECSTREAM_CLIENT = (1 << 21),
76 /**< used to mark client wsi as bound to secure stream */
77 LCCSCF_SECSTREAM_PROXY_LINK = (1 << 22),
78 /**< client is a link between SS client and SS proxy */
79 LCCSCF_SECSTREAM_PROXY_ONWARD = (1 << 23),
80 /**< client the SS proxy's onward connection */
81
82 LCCSCF_IP_LOW_LATENCY = (1 << 24),
83 /**< set the "low delay" bit on the IP packets of this connection */
84 LCCSCF_IP_HIGH_THROUGHPUT = (1 << 25),
85 /**< set the "high throughput" bit on the IP packets of this
86 * connection */
87 LCCSCF_IP_HIGH_RELIABILITY = (1 << 26),
88 /**< set the "high reliability" bit on the IP packets of this
89 * connection */
90 LCCSCF_IP_LOW_COST = (1 << 27),
91 /**< set the "minimize monetary cost" bit on the IP packets of this
92 * connection */
93 LCCSCF_CONMON = (1 << 28),
94 /**< If LWS_WITH_CONMON enabled for build, keeps a copy of the
95 * getaddrinfo results so they can be queried subsequently */
96 LCCSCF_ACCEPT_TLS_DOWNGRADE_REDIRECTS = (1 << 29),
97 /**< By default lws rejects https redirecting to http. Set this
98 * flag on the client connection to allow it. */
99 LCCSCF_CACHE_COOKIES = (1 << 30),
100 /**< If built with -DLWS_WITH_CACHE_NSCOOKIEJAR, store and reapply
101 * http cookies in a Netscape Cookie Jar on this connection */
102};
103
104/** struct lws_client_connect_info - parameters to connect with when using
105 * lws_client_connect_via_info() */
106
107struct lws_client_connect_info {
108 struct lws_context *context;
109 /**< lws context to create connection in */
110 const char *address;
111 /**< remote address to connect to */
112 int port;
113 /**< remote port to connect to */
114 int ssl_connection;
115 /**< 0, or a combination of LCCSCF_ flags */
116 const char *path;
117 /**< URI path. Prefix with + for a UNIX socket. (+@ for
118 * a Linux abstract-namespace socket) */
119 const char *host;
120 /**< content of host header */
121 const char *origin;
122 /**< content of origin header */
123 const char *protocol;
124 /**< list of ws protocols we could accept */
125 int ietf_version_or_minus_one;
126 /**< deprecated: currently leave at 0 or -1 */
127 void *userdata;
128 /**< if non-NULL, use this as wsi user_data instead of malloc it */
129 const void *client_exts;
130 /**< UNUSED... provide in info.extensions at context creation time */
131 const char *method;
132 /**< if non-NULL, do this http method instead of ws[s] upgrade.
133 * use "GET" to be a simple http client connection. "RAW" gets
134 * you a connected socket that lws itself will leave alone once
135 * connected. */
136 struct lws *parent_wsi;
137 /**< if another wsi is responsible for this connection, give it here.
138 * this is used to make sure if the parent closes so do any
139 * child connections first. */
140 const char *uri_replace_from;
141 /**< if non-NULL, when this string is found in URIs in
142 * text/html content-encoding, it's replaced with uri_replace_to */
143 const char *uri_replace_to;
144 /**< see uri_replace_from */
145 struct lws_vhost *vhost;
146 /**< vhost to bind to (used to determine related SSL_CTX) */
147 struct lws **pwsi;
148 /**< if not NULL, store the new wsi here early in the connection
149 * process. Although we return the new wsi, the call to create the
150 * client connection does progress the connection somewhat and may
151 * meet an error that will result in the connection being scrubbed and
152 * NULL returned. While the wsi exists though, he may process a
153 * callback like CLIENT_CONNECTION_ERROR with his wsi: this gives the
154 * user callback a way to identify which wsi it is that faced the error
155 * even before the new wsi is returned and even if ultimately no wsi
156 * is returned.
157 */
158 const char *iface;
159 /**< NULL to allow routing on any interface, or interface name or IP
160 * to bind the socket to */
161 const char *local_protocol_name;
162 /**< NULL: .protocol is used both to select the local protocol handler
163 * to bind to and as the list of remote ws protocols we could
164 * accept.
165 * non-NULL: this protocol name is used to bind the connection to
166 * the local protocol handler. .protocol is used for the
167 * list of remote ws protocols we could accept */
168 const char *alpn;
169 /**< NULL: allow lws default ALPN list, from vhost if present or from
170 * list of roles built into lws
171 * non-NULL: require one from provided comma-separated list of alpn
172 * tokens
173 */
174
175 struct lws_sequencer *seq;
176 /**< NULL, or an lws_seq_t that wants to be given messages about
177 * this wsi's lifecycle as it connects, errors or closes.
178 */
179
180 void *opaque_user_data;
181 /**< This data has no meaning to lws but is applied to the client wsi
182 * and can be retrieved by user code with lws_get_opaque_user_data().
183 * It's also provided with sequencer messages if the wsi is bound to
184 * an lws_seq_t.
185 */
186
187 const lws_retry_bo_t *retry_and_idle_policy;
188 /**< optional retry and idle policy to apply to this connection.
189 * Currently only the idle parts are applied to the connection.
190 */
191
192 int manual_initial_tx_credit;
193 /**< if LCCSCF_H2_MANUAL_REFLOW is set, this becomes the initial tx
194 * credit for the stream.
195 */
196
197 uint8_t sys_tls_client_cert;
198 /**< 0 means no client cert. 1+ means apply lws_system client cert 0+
199 * to the client connection.
200 */
201
202 uint8_t priority;
203 /**< 0 means normal priority... otherwise sets the IP priority on
204 * packets coming from this connection, from 1 - 7. Setting 7
205 * (network management priority) requires CAP_NET_ADMIN capability but
206 * the others can be set by anyone.
207 */
208
209#if defined(LWS_ROLE_MQTT)
210 const lws_mqtt_client_connect_param_t *mqtt_cp;
211#else
212 void *mqtt_cp;
213#endif
214
215#if defined(LWS_WITH_SYS_FAULT_INJECTION)
216 lws_fi_ctx_t fic;
217 /**< Attach external Fault Injection context to the client wsi,
218 * hierarchy is wsi -> vhost -> context */
219#endif
220 /* for convenience, available when FI disabled in build */
221 const char *fi_wsi_name;
222 /**< specific Fault Injection namespace name for wsi created for this
223 * connection, allows targeting by "wsi=XXX/..." if you give XXX here.
224 */
225
226 uint16_t keep_warm_secs;
227 /**< 0 means 5s. If the client connection to the endpoint becomes idle,
228 * defer closing it for this many seconds in case another outgoing
229 * connection to the same endpoint turns up.
230 */
231
232 lws_log_cx_t *log_cx;
233 /**< NULL to use lws_context log context, else a pointer to a log
234 * context template to take a copy of for this wsi. Used to isolate
235 * wsi-specific logs into their own stream or file.
236 */
237
238 /* Add new things just above here ---^
239 * This is part of the ABI, don't needlessly break compatibility
240 *
241 * The below is to ensure later library versions with new
242 * members added above will see 0 (default) even if the app
243 * was not built against the newer headers.
244 */
245
246 void *_unused[4]; /**< dummy */
247};
248
249/**
250 * lws_client_connect_via_info() - Connect to another websocket server
251 * \param ccinfo: pointer to lws_client_connect_info struct
252 *
253 * This function creates a connection to a remote server using the
254 * information provided in ccinfo.
255 */
256LWS_VISIBLE LWS_EXTERN struct lws *
257lws_client_connect_via_info(const struct lws_client_connect_info *ccinfo);
258
259/**
260 * lws_init_vhost_client_ssl() - also enable client SSL on an existing vhost
261 *
262 * \param info: client ssl related info
263 * \param vhost: which vhost to initialize client ssl operations on
264 *
265 * You only need to call this if you plan on using SSL client connections on
266 * the vhost. For non-SSL client connections, it's not necessary to call this.
267 *
268 * The following members of info are used during the call
269 *
270 * - options must have LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT set,
271 * otherwise the call does nothing
272 * - provided_client_ssl_ctx must be NULL to get a generated client
273 * ssl context, otherwise you can pass a prepared one in by setting it
274 * - ssl_cipher_list may be NULL or set to the client valid cipher list
275 * - ssl_ca_filepath may be NULL or client cert filepath
276 * - ssl_cert_filepath may be NULL or client cert filepath
277 * - ssl_private_key_filepath may be NULL or client cert private key
278 *
279 * You must create your vhost explicitly if you want to use this, so you have
280 * a pointer to the vhost. Create the context first with the option flag
281 * LWS_SERVER_OPTION_EXPLICIT_VHOSTS and then call lws_create_vhost() with
282 * the same info struct.
283 */
284LWS_VISIBLE LWS_EXTERN int
285lws_init_vhost_client_ssl(const struct lws_context_creation_info *info,
286 struct lws_vhost *vhost);
287/**
288 * lws_http_client_read() - consume waiting received http client data
289 *
290 * \param wsi: client connection
291 * \param buf: pointer to buffer pointer - fill with pointer to your buffer
292 * \param len: pointer to chunk length - fill with max length of buffer
293 *
294 * This is called when the user code is notified client http data has arrived.
295 * The user code may choose to delay calling it to consume the data, for example
296 * waiting until an onward connection is writeable.
297 *
298 * For non-chunked connections, up to len bytes of buf are filled with the
299 * received content. len is set to the actual amount filled before return.
300 *
301 * For chunked connections, the linear buffer content contains the chunking
302 * headers and it cannot be passed in one lump. Instead, this function will
303 * call back LWS_CALLBACK_RECEIVE_CLIENT_HTTP_READ with in pointing to the
304 * chunk start and len set to the chunk length. There will be as many calls
305 * as there are chunks or partial chunks in the buffer.
306 */
307LWS_VISIBLE LWS_EXTERN int
308lws_http_client_read(struct lws *wsi, char **buf, int *len);
309
310/**
311 * lws_http_client_http_response() - get last HTTP response code
312 *
313 * \param wsi: client connection
314 *
315 * Returns the last server response code, eg, 200 for client http connections.
316 * If there is no valid response, it will return 0.
317 *
318 * You should capture this during the LWS_CALLBACK_ESTABLISHED_CLIENT_HTTP
319 * callback, because after that the memory reserved for storing the related
320 * headers is freed and this value is lost.
321 */
322LWS_VISIBLE LWS_EXTERN unsigned int
323lws_http_client_http_response(struct lws *wsi);
324
325/**
326 * lws_tls_client_vhost_extra_cert_mem() - add more certs to vh client tls ctx
327 *
328 * \param vh: the vhost to give more client certs to
329 * \param der: pointer to der format additional cert
330 * \param der_len: size in bytes of der
331 *
332 * After the vhost is created with one cert for client verification, you
333 * can add additional, eg, intermediate, certs to the client tls context
334 * of the vhost, for use with validating the incoming server cert(s).
335 */
336LWS_VISIBLE LWS_EXTERN int
337lws_tls_client_vhost_extra_cert_mem(struct lws_vhost *vh,
338 const uint8_t *der, size_t der_len);
339
340/**
341 * lws_client_http_body_pending() - control if client connection needs to send body
342 *
343 * \param wsi: client connection
344 * \param something_left_to_send: nonzero if need to send more body, 0 (default)
345 * if nothing more to send
346 *
347 * If you will send payload data with your HTTP client connection, eg, for POST,
348 * when you set the related http headers in
349 * LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER callback you should also call
350 * this API with something_left_to_send nonzero, and call
351 * lws_callback_on_writable(wsi);
352 *
353 * After sending the headers, lws will call your callback with
354 * LWS_CALLBACK_CLIENT_HTTP_WRITEABLE reason when writable. You can send the
355 * next part of the http body payload, calling lws_callback_on_writable(wsi);
356 * if there is more to come, or lws_client_http_body_pending(wsi, 0); to
357 * let lws know the last part is sent and the connection can move on.
358 */
359LWS_VISIBLE LWS_EXTERN void
360lws_client_http_body_pending(struct lws *wsi, int something_left_to_send);
361
362/**
363 * lws_client_http_multipart() - issue appropriate multipart header or trailer
364 *
365 * \param wsi: client connection
366 * \param name: multipart header name field, or NULL if end of multipart
367 * \param filename: multipart header filename field, or NULL if none
368 * \param content_type: multipart header content-type part, or NULL if none
369 * \param p: pointer to position in buffer
370 * \param end: end of buffer
371 *
372 * This issues a multipart mime boundary, or terminator if name = NULL.
373 *
374 * Returns 0 if OK or nonzero if couldn't fit in buffer
375 */
376LWS_VISIBLE LWS_EXTERN int
377lws_client_http_multipart(struct lws *wsi, const char *name,
378 const char *filename, const char *content_type,
379 char **p, char *end);
380
381/**
382 * lws_http_basic_auth_gen() - helper to encode client basic auth string
383 *
384 * \param user: user name
385 * \param pw: password
386 * \param buf: where to store base64 result
387 * \param len: max usable size of buf
388 *
389 * Encodes a username and password in Basic Auth format for use with the
390 * Authorization header. On return, buf is filled with something like
391 * "Basic QWxhZGRpbjpPcGVuU2VzYW1l".
392 */
393LWS_VISIBLE LWS_EXTERN int
394lws_http_basic_auth_gen(const char *user, const char *pw, char *buf, size_t len);
395
396/**
397 * lws_tls_session_is_reused() - returns nonzero if tls session was cached
398 *
399 * \param wsi: the wsi
400 *
401 * Returns zero if the tls session is fresh, else nonzero if the tls session was
402 * taken from the cache. If lws is built with LWS_WITH_TLS_SESSIONS and the vhost
403 * was created with the option LWS_SERVER_OPTION_ENABLE_TLS_SESSION_CACHE, then
404 * on full tls session establishment of a client connection, the session is added
405 * to the tls cache.
406 *
407 * This lets you find out if your session was new (0) or from the cache (nonzero),
408 * it'a mainly useful for stats and testing.
409 */
410LWS_VISIBLE LWS_EXTERN int
411lws_tls_session_is_reused(struct lws *wsi);
412
413///@}
414