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1 #ifndef HEADER_CURL_CFILTERS_H
2 #define HEADER_CURL_CFILTERS_H
3 /***************************************************************************
4  *                                  _   _ ____  _
5  *  Project                     ___| | | |  _ \| |
6  *                             / __| | | | |_) | |
7  *                            | (__| |_| |  _ <| |___
8  *                             \___|\___/|_| \_\_____|
9  *
10  * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
11  *
12  * This software is licensed as described in the file COPYING, which
13  * you should have received as part of this distribution. The terms
14  * are also available at https://curl.se/docs/copyright.html.
15  *
16  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
17  * copies of the Software, and permit persons to whom the Software is
18  * furnished to do so, under the terms of the COPYING file.
19  *
20  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
21  * KIND, either express or implied.
22  *
23  * SPDX-License-Identifier: curl
24  *
25  ***************************************************************************/
26 
27 #include "timediff.h"
28 
29 struct Curl_cfilter;
30 struct Curl_easy;
31 struct Curl_dns_entry;
32 struct connectdata;
33 struct ip_quadruple;
34 
35 /* Callback to destroy resources held by this filter instance.
36  * Implementations MUST NOT chain calls to cf->next.
37  */
38 typedef void     Curl_cft_destroy_this(struct Curl_cfilter *cf,
39                                        struct Curl_easy *data);
40 
41 /* Callback to close the connection immediately. */
42 typedef void     Curl_cft_close(struct Curl_cfilter *cf,
43                                 struct Curl_easy *data);
44 
45 /* Callback to close the connection filter gracefully, non-blocking.
46  * Implementations MUST NOT chain calls to cf->next.
47  */
48 typedef CURLcode Curl_cft_shutdown(struct Curl_cfilter *cf,
49                                    struct Curl_easy *data,
50                                    bool *done);
51 
52 typedef CURLcode Curl_cft_connect(struct Curl_cfilter *cf,
53                                   struct Curl_easy *data,
54                                   bool blocking, bool *done);
55 
56 /* Return the hostname and port the connection goes to.
57  * This may change with the connection state of filters when tunneling
58  * is involved.
59  * @param cf     the filter to ask
60  * @param data   the easy handle currently active
61  * @param phost  on return, points to the relevant, real hostname.
62  *               this is owned by the connection.
63  * @param pdisplay_host  on return, points to the printable hostname.
64  *               this is owned by the connection.
65  * @param pport  on return, contains the port number
66  */
67 typedef void     Curl_cft_get_host(struct Curl_cfilter *cf,
68                                   struct Curl_easy *data,
69                                   const char **phost,
70                                   const char **pdisplay_host,
71                                   int *pport);
72 
73 struct easy_pollset;
74 
75 /* Passing in an easy_pollset for monitoring of sockets, let
76  * filters add or remove sockets actions (CURL_POLL_OUT, CURL_POLL_IN).
77  * This may add a socket or, in case no actions remain, remove
78  * a socket from the set.
79  *
80  * Filter implementations need to call filters "below" *after* they have
81  * made their adjustments. This allows lower filters to override "upper"
82  * actions. If a "lower" filter is unable to write, it needs to be able
83  * to disallow POLL_OUT.
84  *
85  * A filter without own restrictions/preferences should not modify
86  * the pollset. Filters, whose filter "below" is not connected, should
87  * also do no adjustments.
88  *
89  * Examples: a TLS handshake, while ongoing, might remove POLL_IN when it
90  * needs to write, or vice versa. An HTTP/2 filter might remove POLL_OUT when
91  * a stream window is exhausted and a WINDOW_UPDATE needs to be received first
92  * and add instead POLL_IN.
93  *
94  * @param cf     the filter to ask
95  * @param data   the easy handle the pollset is about
96  * @param ps     the pollset (inout) for the easy handle
97  */
98 typedef void     Curl_cft_adjust_pollset(struct Curl_cfilter *cf,
99                                           struct Curl_easy *data,
100                                           struct easy_pollset *ps);
101 
102 typedef bool     Curl_cft_data_pending(struct Curl_cfilter *cf,
103                                        const struct Curl_easy *data);
104 
105 typedef ssize_t  Curl_cft_send(struct Curl_cfilter *cf,
106                                struct Curl_easy *data, /* transfer */
107                                const void *buf,        /* data to write */
108                                size_t len,             /* amount to write */
109                                bool eos,               /* last chunk */
110                                CURLcode *err);         /* error to return */
111 
112 typedef ssize_t  Curl_cft_recv(struct Curl_cfilter *cf,
113                                struct Curl_easy *data, /* transfer */
114                                char *buf,              /* store data here */
115                                size_t len,             /* amount to read */
116                                CURLcode *err);         /* error to return */
117 
118 typedef bool     Curl_cft_conn_is_alive(struct Curl_cfilter *cf,
119                                         struct Curl_easy *data,
120                                         bool *input_pending);
121 
122 typedef CURLcode Curl_cft_conn_keep_alive(struct Curl_cfilter *cf,
123                                           struct Curl_easy *data);
124 
125 /**
126  * Events/controls for connection filters, their arguments and
127  * return code handling. Filter callbacks are invoked "top down".
128  * Return code handling:
129  * "first fail" meaning that the first filter returning != CURLE_OK, will
130  *              abort further event distribution and determine the result.
131  * "ignored" meaning return values are ignored and the event is distributed
132  *           to all filters in the chain. Overall result is always CURLE_OK.
133  */
134 /*      data event                          arg1       arg2     return */
135 #define CF_CTRL_DATA_SETUP            4  /* 0          NULL     first fail */
136 #define CF_CTRL_DATA_IDLE             5  /* 0          NULL     first fail */
137 #define CF_CTRL_DATA_PAUSE            6  /* on/off     NULL     first fail */
138 #define CF_CTRL_DATA_DONE             7  /* premature  NULL     ignored */
139 #define CF_CTRL_DATA_DONE_SEND        8  /* 0          NULL     ignored */
140 /* update conn info at connection and data */
141 #define CF_CTRL_CONN_INFO_UPDATE (256+0) /* 0          NULL     ignored */
142 #define CF_CTRL_FORGET_SOCKET    (256+1) /* 0          NULL     ignored */
143 #define CF_CTRL_FLUSH            (256+2) /* 0          NULL     first fail */
144 
145 /**
146  * Handle event/control for the filter.
147  * Implementations MUST NOT chain calls to cf->next.
148  */
149 typedef CURLcode Curl_cft_cntrl(struct Curl_cfilter *cf,
150                                 struct Curl_easy *data,
151                                 int event, int arg1, void *arg2);
152 
153 
154 /**
155  * Queries to ask via a `Curl_cft_query *query` method on a cfilter chain.
156  * - MAX_CONCURRENT: the maximum number of parallel transfers the filter
157  *                   chain expects to handle at the same time.
158  *                   default: 1 if no filter overrides.
159  * - CONNECT_REPLY_MS: milliseconds until the first indication of a server
160  *                   response was received on a connect. For TCP, this
161  *                   reflects the time until the socket connected. On UDP
162  *                   this gives the time the first bytes from the server
163  *                   were received.
164  *                   -1 if not determined yet.
165  * - CF_QUERY_SOCKET: the socket used by the filter chain
166  * - CF_QUERY_NEED_FLUSH: TRUE iff any of the filters have unsent data
167  * - CF_QUERY_IP_INFO: res1 says if connection used IPv6, res2 is the
168  *                   ip quadruple
169  */
170 /*      query                             res1       res2     */
171 #define CF_QUERY_MAX_CONCURRENT     1  /* number     -        */
172 #define CF_QUERY_CONNECT_REPLY_MS   2  /* number     -        */
173 #define CF_QUERY_SOCKET             3  /* -          curl_socket_t */
174 #define CF_QUERY_TIMER_CONNECT      4  /* -          struct curltime */
175 #define CF_QUERY_TIMER_APPCONNECT   5  /* -          struct curltime */
176 #define CF_QUERY_STREAM_ERROR       6  /* error code - */
177 #define CF_QUERY_NEED_FLUSH         7  /* TRUE/FALSE - */
178 #define CF_QUERY_IP_INFO            8  /* TRUE/FALSE struct ip_quadruple */
179 #define CF_QUERY_HTTP_VERSION       9  /* number (10/11/20/30)   -  */
180 
181 /**
182  * Query the cfilter for properties. Filters ignorant of a query will
183  * pass it "down" the filter chain.
184  */
185 typedef CURLcode Curl_cft_query(struct Curl_cfilter *cf,
186                                 struct Curl_easy *data,
187                                 int query, int *pres1, void *pres2);
188 
189 /**
190  * Type flags for connection filters. A filter can have none, one or
191  * many of those. Use to evaluate state/capabilities of a filter chain.
192  *
193  * CF_TYPE_IP_CONNECT: provides an IP connection or sth equivalent, like
194  *                     a CONNECT tunnel, a UNIX domain socket, a QUIC
195  *                     connection, etc.
196  * CF_TYPE_SSL:        provide SSL/TLS
197  * CF_TYPE_MULTIPLEX:  provides multiplexing of easy handles
198  * CF_TYPE_PROXY       provides proxying
199  * CF_TYPE_HTTP        implement a version of the HTTP protocol
200  */
201 #define CF_TYPE_IP_CONNECT  (1 << 0)
202 #define CF_TYPE_SSL         (1 << 1)
203 #define CF_TYPE_MULTIPLEX   (1 << 2)
204 #define CF_TYPE_PROXY       (1 << 3)
205 #define CF_TYPE_HTTP        (1 << 4)
206 
207 /* A connection filter type, e.g. specific implementation. */
208 struct Curl_cftype {
209   const char *name;                       /* name of the filter type */
210   int flags;                              /* flags of filter type */
211   int log_level;                          /* log level for such filters */
212   Curl_cft_destroy_this *destroy;         /* destroy resources of this cf */
213   Curl_cft_connect *do_connect;           /* establish connection */
214   Curl_cft_close *do_close;               /* close conn */
215   Curl_cft_shutdown *do_shutdown;         /* shutdown conn */
216   Curl_cft_get_host *get_host;            /* host filter talks to */
217   Curl_cft_adjust_pollset *adjust_pollset; /* adjust transfer poll set */
218   Curl_cft_data_pending *has_data_pending;/* conn has data pending */
219   Curl_cft_send *do_send;                 /* send data */
220   Curl_cft_recv *do_recv;                 /* receive data */
221   Curl_cft_cntrl *cntrl;                  /* events/control */
222   Curl_cft_conn_is_alive *is_alive;       /* FALSE if conn is dead, Jim! */
223   Curl_cft_conn_keep_alive *keep_alive;   /* try to keep it alive */
224   Curl_cft_query *query;                  /* query filter chain */
225 };
226 
227 /* A connection filter instance, e.g. registered at a connection */
228 struct Curl_cfilter {
229   const struct Curl_cftype *cft; /* the type providing implementation */
230   struct Curl_cfilter *next;     /* next filter in chain */
231   void *ctx;                     /* filter type specific settings */
232   struct connectdata *conn;      /* the connection this filter belongs to */
233   int sockindex;                 /* the index the filter is installed at */
234   BIT(connected);                /* != 0 iff this filter is connected */
235   BIT(shutdown);                 /* != 0 iff this filter has shut down */
236 };
237 
238 /* Default implementations for the type functions, implementing nop. */
239 void Curl_cf_def_destroy_this(struct Curl_cfilter *cf,
240                               struct Curl_easy *data);
241 
242 /* Default implementations for the type functions, implementing pass-through
243  * the filter chain. */
244 void     Curl_cf_def_get_host(struct Curl_cfilter *cf, struct Curl_easy *data,
245                               const char **phost, const char **pdisplay_host,
246                               int *pport);
247 void     Curl_cf_def_adjust_pollset(struct Curl_cfilter *cf,
248                                      struct Curl_easy *data,
249                                      struct easy_pollset *ps);
250 bool     Curl_cf_def_data_pending(struct Curl_cfilter *cf,
251                                   const struct Curl_easy *data);
252 ssize_t  Curl_cf_def_send(struct Curl_cfilter *cf, struct Curl_easy *data,
253                           const void *buf, size_t len, bool eos,
254                           CURLcode *err);
255 ssize_t  Curl_cf_def_recv(struct Curl_cfilter *cf, struct Curl_easy *data,
256                           char *buf, size_t len, CURLcode *err);
257 CURLcode Curl_cf_def_cntrl(struct Curl_cfilter *cf,
258                                 struct Curl_easy *data,
259                                 int event, int arg1, void *arg2);
260 bool     Curl_cf_def_conn_is_alive(struct Curl_cfilter *cf,
261                                    struct Curl_easy *data,
262                                    bool *input_pending);
263 CURLcode Curl_cf_def_conn_keep_alive(struct Curl_cfilter *cf,
264                                      struct Curl_easy *data);
265 CURLcode Curl_cf_def_query(struct Curl_cfilter *cf,
266                            struct Curl_easy *data,
267                            int query, int *pres1, void *pres2);
268 CURLcode Curl_cf_def_shutdown(struct Curl_cfilter *cf,
269                               struct Curl_easy *data, bool *done);
270 
271 /**
272  * Create a new filter instance, unattached to the filter chain.
273  * Use Curl_conn_cf_add() to add it to the chain.
274  * @param pcf  on success holds the created instance
275  * @param cft   the filter type
276  * @param ctx  the type specific context to use
277  */
278 CURLcode Curl_cf_create(struct Curl_cfilter **pcf,
279                         const struct Curl_cftype *cft,
280                         void *ctx);
281 
282 /**
283  * Add a filter instance to the `sockindex` filter chain at connection
284  * `conn`. The filter must not already be attached. It is inserted at
285  * the start of the chain (top).
286  */
287 void Curl_conn_cf_add(struct Curl_easy *data,
288                       struct connectdata *conn,
289                       int sockindex,
290                       struct Curl_cfilter *cf);
291 
292 /**
293  * Insert a filter (chain) after `cf_at`.
294  * `cf_new` must not already be attached.
295  */
296 void Curl_conn_cf_insert_after(struct Curl_cfilter *cf_at,
297                                struct Curl_cfilter *cf_new);
298 
299 /**
300  * Discard, e.g. remove and destroy `discard` iff
301  * it still is in the filter chain below `cf`. If `discard`
302  * is no longer found beneath `cf` return FALSE.
303  * if `destroy_always` is TRUE, will call `discard`s destroy
304  * function and free it even if not found in the subchain.
305  */
306 bool Curl_conn_cf_discard_sub(struct Curl_cfilter *cf,
307                               struct Curl_cfilter *discard,
308                               struct Curl_easy *data,
309                               bool destroy_always);
310 
311 /**
312  * Discard all cfilters starting with `*pcf` and clearing it afterwards.
313  */
314 void Curl_conn_cf_discard_chain(struct Curl_cfilter **pcf,
315                                 struct Curl_easy *data);
316 
317 /**
318  * Remove and destroy all filters at chain `sockindex` on connection `conn`.
319  */
320 void Curl_conn_cf_discard_all(struct Curl_easy *data,
321                               struct connectdata *conn,
322                               int sockindex);
323 
324 
325 CURLcode Curl_conn_cf_connect(struct Curl_cfilter *cf,
326                               struct Curl_easy *data,
327                               bool blocking, bool *done);
328 void Curl_conn_cf_close(struct Curl_cfilter *cf, struct Curl_easy *data);
329 ssize_t Curl_conn_cf_send(struct Curl_cfilter *cf, struct Curl_easy *data,
330                           const void *buf, size_t len, bool eos,
331                           CURLcode *err);
332 ssize_t Curl_conn_cf_recv(struct Curl_cfilter *cf, struct Curl_easy *data,
333                           char *buf, size_t len, CURLcode *err);
334 CURLcode Curl_conn_cf_cntrl(struct Curl_cfilter *cf,
335                             struct Curl_easy *data,
336                             bool ignore_result,
337                             int event, int arg1, void *arg2);
338 
339 /**
340  * Determine if the connection filter chain is using SSL to the remote host
341  * (or will be once connected).
342  */
343 bool Curl_conn_cf_is_ssl(struct Curl_cfilter *cf);
344 
345 /**
346  * Get the socket used by the filter chain starting at `cf`.
347  * Returns CURL_SOCKET_BAD if not available.
348  */
349 curl_socket_t Curl_conn_cf_get_socket(struct Curl_cfilter *cf,
350                                       struct Curl_easy *data);
351 
352 CURLcode Curl_conn_cf_get_ip_info(struct Curl_cfilter *cf,
353                                   struct Curl_easy *data,
354                                   int *is_ipv6, struct ip_quadruple *ipquad);
355 
356 bool Curl_conn_cf_needs_flush(struct Curl_cfilter *cf,
357                               struct Curl_easy *data);
358 
359 #define CURL_CF_SSL_DEFAULT  -1
360 #define CURL_CF_SSL_DISABLE  0
361 #define CURL_CF_SSL_ENABLE   1
362 
363 /**
364  * Bring the filter chain at `sockindex` for connection `data->conn` into
365  * connected state. Which will set `*done` to TRUE.
366  * This can be called on an already connected chain with no side effects.
367  * When not `blocking`, calls may return without error and `*done != TRUE`,
368  * while the individual filters negotiated the connection.
369  */
370 CURLcode Curl_conn_connect(struct Curl_easy *data, int sockindex,
371                            bool blocking, bool *done);
372 
373 /**
374  * Check if the filter chain at `sockindex` for connection `conn` is
375  * completely connected.
376  */
377 bool Curl_conn_is_connected(struct connectdata *conn, int sockindex);
378 
379 /**
380  * Determine if we have reached the remote host on IP level, e.g.
381  * have a TCP connection. This turns TRUE before a possible SSL
382  * handshake has been started/done.
383  */
384 bool Curl_conn_is_ip_connected(struct Curl_easy *data, int sockindex);
385 
386 /**
387  * Determine if the connection is using SSL to the remote host
388  * (or will be once connected). This will return FALSE, if SSL
389  * is only used in proxying and not for the tunnel itself.
390  */
391 bool Curl_conn_is_ssl(struct connectdata *conn, int sockindex);
392 
393 /**
394  * Connection provides multiplexing of easy handles at `socketindex`.
395  */
396 bool Curl_conn_is_multiplex(struct connectdata *conn, int sockindex);
397 
398 /**
399  * Return the HTTP version used on the FIRSTSOCKET connection filters
400  * or 0 if unknown. Value otherwise is 09, 10, 11, etc.
401  */
402 unsigned char Curl_conn_http_version(struct Curl_easy *data);
403 
404 /**
405  * Close the filter chain at `sockindex` for connection `data->conn`.
406   * Filters remain in place and may be connected again afterwards.
407  */
408 void Curl_conn_close(struct Curl_easy *data, int sockindex);
409 
410 /**
411  * Shutdown the connection at `sockindex` non-blocking, using timeout
412  * from `data->set.shutdowntimeout`, default DEFAULT_SHUTDOWN_TIMEOUT_MS.
413  * Will return CURLE_OK and *done == FALSE if not finished.
414  */
415 CURLcode Curl_conn_shutdown(struct Curl_easy *data, int sockindex, bool *done);
416 
417 /**
418  * Return if data is pending in some connection filter at chain
419  * `sockindex` for connection `data->conn`.
420  */
421 bool Curl_conn_data_pending(struct Curl_easy *data,
422                             int sockindex);
423 
424 /**
425  * Return TRUE if any of the connection filters at chain `sockindex`
426  * have data still to send.
427  */
428 bool Curl_conn_needs_flush(struct Curl_easy *data, int sockindex);
429 
430 /**
431  * Flush any pending data on the connection filters at chain `sockindex`.
432  */
433 CURLcode Curl_conn_flush(struct Curl_easy *data, int sockindex);
434 
435 /**
436  * Return the socket used on data's connection for the index.
437  * Returns CURL_SOCKET_BAD if not available.
438  */
439 curl_socket_t Curl_conn_get_socket(struct Curl_easy *data, int sockindex);
440 
441 /**
442  * Tell filters to forget about the socket at sockindex.
443  */
444 void Curl_conn_forget_socket(struct Curl_easy *data, int sockindex);
445 
446 /**
447  * Adjust the pollset for the filter chain startgin at `cf`.
448  */
449 void Curl_conn_cf_adjust_pollset(struct Curl_cfilter *cf,
450                                  struct Curl_easy *data,
451                                  struct easy_pollset *ps);
452 
453 /**
454  * Adjust pollset from filters installed at transfer's connection.
455  */
456 void Curl_conn_adjust_pollset(struct Curl_easy *data,
457                                struct easy_pollset *ps);
458 
459 /**
460  * Curl_poll() the filter chain at `cf` with timeout `timeout_ms`.
461  * Returns 0 on timeout, negative on error or number of sockets
462  * with requested poll events.
463  */
464 int Curl_conn_cf_poll(struct Curl_cfilter *cf,
465                       struct Curl_easy *data,
466                       timediff_t timeout_ms);
467 
468 /**
469  * Receive data through the filter chain at `sockindex` for connection
470  * `data->conn`. Copy at most `len` bytes into `buf`. Return the
471  * actual number of bytes copied or a negative value on error.
472  * The error code is placed into `*code`.
473  */
474 ssize_t Curl_cf_recv(struct Curl_easy *data, int sockindex, char *buf,
475                      size_t len, CURLcode *code);
476 
477 /**
478  * Send `len` bytes of data from `buf` through the filter chain `sockindex`
479  * at connection `data->conn`. Return the actual number of bytes written
480  * or a negative value on error.
481  * The error code is placed into `*code`.
482  */
483 ssize_t Curl_cf_send(struct Curl_easy *data, int sockindex,
484                      const void *buf, size_t len, bool eos, CURLcode *code);
485 
486 /**
487  * Notify connection filters that they need to setup data for
488  * a transfer.
489  */
490 CURLcode Curl_conn_ev_data_setup(struct Curl_easy *data);
491 
492 /**
493  * Notify connection filters that now would be a good time to
494  * perform any idle, e.g. time related, actions.
495  */
496 CURLcode Curl_conn_ev_data_idle(struct Curl_easy *data);
497 
498 /**
499  * Notify connection filters that the transfer represented by `data`
500  * is done with sending data (e.g. has uploaded everything).
501  */
502 void Curl_conn_ev_data_done_send(struct Curl_easy *data);
503 
504 /**
505  * Notify connection filters that the transfer represented by `data`
506  * is finished - eventually premature, e.g. before being complete.
507  */
508 void Curl_conn_ev_data_done(struct Curl_easy *data, bool premature);
509 
510 /**
511  * Notify connection filters that the transfer of data is paused/unpaused.
512  */
513 CURLcode Curl_conn_ev_data_pause(struct Curl_easy *data, bool do_pause);
514 
515 /**
516  * Check if FIRSTSOCKET's cfilter chain deems connection alive.
517  */
518 bool Curl_conn_is_alive(struct Curl_easy *data, struct connectdata *conn,
519                         bool *input_pending);
520 
521 /**
522  * Try to upkeep the connection filters at sockindex.
523  */
524 CURLcode Curl_conn_keep_alive(struct Curl_easy *data,
525                               struct connectdata *conn,
526                               int sockindex);
527 
528 #ifdef UNITTESTS
529 void Curl_cf_def_close(struct Curl_cfilter *cf, struct Curl_easy *data);
530 #endif
531 void Curl_conn_get_host(struct Curl_easy *data, int sockindex,
532                         const char **phost, const char **pdisplay_host,
533                         int *pport);
534 
535 /**
536  * Get the maximum number of parallel transfers the connection
537  * expects to be able to handle at `sockindex`.
538  */
539 size_t Curl_conn_get_max_concurrent(struct Curl_easy *data,
540                                     struct connectdata *conn,
541                                     int sockindex);
542 
543 /**
544  * Get the underlying error code for a transfer stream or 0 if not known.
545  */
546 int Curl_conn_get_stream_error(struct Curl_easy *data,
547                                struct connectdata *conn,
548                                int sockindex);
549 
550 /**
551  * Get the index of the given socket in the connection's sockets.
552  * Useful in calling `Curl_conn_send()/Curl_conn_recv()` with the
553  * correct socket index.
554  */
555 int Curl_conn_sockindex(struct Curl_easy *data, curl_socket_t sockfd);
556 
557 /*
558  * Receive data on the connection, using FIRSTSOCKET/SECONDARYSOCKET.
559  * Will return CURLE_AGAIN iff blocked on receiving.
560  */
561 CURLcode Curl_conn_recv(struct Curl_easy *data, int sockindex,
562                         char *buf, size_t buffersize,
563                         ssize_t *pnread);
564 
565 /*
566  * Send data on the connection, using FIRSTSOCKET/SECONDARYSOCKET.
567  * Will return CURLE_AGAIN iff blocked on sending.
568  */
569 CURLcode Curl_conn_send(struct Curl_easy *data, int sockindex,
570                         const void *buf, size_t blen, bool eos,
571                         size_t *pnwritten);
572 
573 
574 void Curl_pollset_reset(struct Curl_easy *data,
575                         struct easy_pollset *ps);
576 
577 /* Change the poll flags (CURL_POLL_IN/CURL_POLL_OUT) to the poll set for
578  * socket `sock`. If the socket is not already part of the poll set, it
579  * will be added.
580  * If the socket is present and all poll flags are cleared, it will be removed.
581  */
582 void Curl_pollset_change(struct Curl_easy *data,
583                          struct easy_pollset *ps, curl_socket_t sock,
584                          int add_flags, int remove_flags);
585 
586 void Curl_pollset_set(struct Curl_easy *data,
587                       struct easy_pollset *ps, curl_socket_t sock,
588                       bool do_in, bool do_out);
589 
590 #define Curl_pollset_add_in(data, ps, sock) \
591           Curl_pollset_change((data), (ps), (sock), CURL_POLL_IN, 0)
592 #define Curl_pollset_add_out(data, ps, sock) \
593           Curl_pollset_change((data), (ps), (sock), CURL_POLL_OUT, 0)
594 #define Curl_pollset_add_inout(data, ps, sock) \
595           Curl_pollset_change((data), (ps), (sock), \
596                                CURL_POLL_IN|CURL_POLL_OUT, 0)
597 #define Curl_pollset_set_in_only(data, ps, sock) \
598           Curl_pollset_change((data), (ps), (sock), \
599                                CURL_POLL_IN, CURL_POLL_OUT)
600 #define Curl_pollset_set_out_only(data, ps, sock) \
601           Curl_pollset_change((data), (ps), (sock), \
602                                CURL_POLL_OUT, CURL_POLL_IN)
603 
604 void Curl_pollset_add_socks(struct Curl_easy *data,
605                             struct easy_pollset *ps,
606                             int (*get_socks_cb)(struct Curl_easy *data,
607                                                 curl_socket_t *socks));
608 
609 /**
610  * Check if the pollset, as is, wants to read and/or write regarding
611  * the given socket.
612  */
613 void Curl_pollset_check(struct Curl_easy *data,
614                         struct easy_pollset *ps, curl_socket_t sock,
615                         bool *pwant_read, bool *pwant_write);
616 
617 /**
618  * Types and macros used to keep the current easy handle in filter calls,
619  * allowing for nested invocations. See #10336.
620  *
621  * `cf_call_data` is intended to be a member of the cfilter's `ctx` type.
622  * A filter defines the macro `CF_CTX_CALL_DATA` to give access to that.
623  *
624  * With all values 0, the default, this indicates that there is no cfilter
625  * call with `data` ongoing.
626  * Macro `CF_DATA_SAVE` preserves the current `cf_call_data` in a local
627  * variable and sets the `data` given, incrementing the `depth` counter.
628  *
629  * Macro `CF_DATA_RESTORE` restores the old values from the local variable,
630  * while checking that `depth` values are as expected (debug build), catching
631  * cases where a "lower" RESTORE was not called.
632  *
633  * Finally, macro `CF_DATA_CURRENT` gives the easy handle of the current
634  * invocation.
635  */
636 struct cf_call_data {
637   struct Curl_easy *data;
638 #ifdef DEBUGBUILD
639   int depth;
640 #endif
641 };
642 
643 /**
644  * define to access the `struct cf_call_data for a cfilter. Normally
645  * a member in the cfilter's `ctx`.
646  *
647  * #define CF_CTX_CALL_DATA(cf)   -> struct cf_call_data instance
648 */
649 
650 #ifdef DEBUGBUILD
651 
652 #define CF_DATA_SAVE(save, cf, data) \
653   do { \
654     (save) = CF_CTX_CALL_DATA(cf); \
655     DEBUGASSERT((save).data == NULL || (save).depth > 0); \
656     CF_CTX_CALL_DATA(cf).depth++;  \
657     CF_CTX_CALL_DATA(cf).data = (struct Curl_easy *)data; \
658   } while(0)
659 
660 #define CF_DATA_RESTORE(cf, save) \
661   do { \
662     DEBUGASSERT(CF_CTX_CALL_DATA(cf).depth == (save).depth + 1); \
663     DEBUGASSERT((save).data == NULL || (save).depth > 0); \
664     CF_CTX_CALL_DATA(cf) = (save); \
665   } while(0)
666 
667 #else /* DEBUGBUILD */
668 
669 #define CF_DATA_SAVE(save, cf, data) \
670   do { \
671     (save) = CF_CTX_CALL_DATA(cf); \
672     CF_CTX_CALL_DATA(cf).data = (struct Curl_easy *)data; \
673   } while(0)
674 
675 #define CF_DATA_RESTORE(cf, save) \
676   do { \
677     CF_CTX_CALL_DATA(cf) = (save); \
678   } while(0)
679 
680 #endif /* !DEBUGBUILD */
681 
682 #define CF_DATA_CURRENT(cf) \
683   ((cf)? (CF_CTX_CALL_DATA(cf).data) : NULL)
684 
685 #endif /* HEADER_CURL_CFILTERS_H */
686