1 /* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements. See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License. You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 * @file http_protocol.h
19 * @brief HTTP protocol handling
21 * @defgroup APACHE_CORE_PROTO HTTP Protocol Handling
22 * @ingroup APACHE_CORE
26 #ifndef APACHE_HTTP_PROTOCOL_H
27 #define APACHE_HTTP_PROTOCOL_H
30 #include "apr_portable.h"
32 #include "apr_buckets.h"
33 #include "util_filter.h"
40 * This hook allows modules to insert filters for the current error response
41 * @param r the current request
44 AP_DECLARE_HOOK(void,insert_error_filter,(request_rec *r))
46 /** This is an optimization. We keep a record of the filter_rec that
47 * stores the old_write filter, so that we can avoid strcmp's later.
49 AP_DECLARE_DATA extern ap_filter_rec_t *ap_old_write_func;
52 * Prototypes for routines which either talk directly back to the user,
53 * or control the ones that eventually do.
57 * Read an empty request and set reasonable defaults.
58 * @param c The current connection
59 * @return The new request_rec
61 AP_DECLARE(request_rec *) ap_create_request(conn_rec *c);
64 * Read a request and fill in the fields.
65 * @param c The current connection
66 * @return The new request_rec
68 request_rec *ap_read_request(conn_rec *c);
71 * Read the mime-encoded headers.
72 * @param r The current request
74 AP_DECLARE(void) ap_get_mime_headers(request_rec *r);
77 * Optimized version of ap_get_mime_headers() that requires a
78 * temporary brigade to work with
79 * @param r The current request
80 * @param bb temp brigade
82 AP_DECLARE(void) ap_get_mime_headers_core(request_rec *r,
83 apr_bucket_brigade *bb);
85 /* Finish up stuff after a request */
88 * Called at completion of sending the response. It sends the terminating
89 * protocol information.
90 * @param r The current request
92 AP_DECLARE(void) ap_finalize_request_protocol(request_rec *r);
95 * Send error back to client.
96 * @param r The current request
97 * @param recursive_error last arg indicates error status in case we get
98 * an error in the process of trying to deal with an ErrorDocument
99 * to handle some other error. In that case, we print the default
100 * report for the first thing that went wrong, and more briefly report
101 * on the problem with the ErrorDocument.
103 AP_DECLARE(void) ap_send_error_response(request_rec *r, int recursive_error);
105 /* Set last modified header line from the lastmod date of the associated file.
106 * Also, set content length.
108 * May return an error status, typically HTTP_NOT_MODIFIED (that when the
109 * permit_cache argument is set to one).
113 * Set the content length for this request
114 * @param r The current request
115 * @param length The new content length
117 AP_DECLARE(void) ap_set_content_length(request_rec *r, apr_off_t length);
120 * Set the keepalive status for this request
121 * @param r The current request
122 * @return 1 if keepalive can be set, 0 otherwise
124 AP_DECLARE(int) ap_set_keepalive(request_rec *r);
127 * Return the latest rational time from a request/mtime pair. Mtime is
128 * returned unless it's in the future, in which case we return the current time.
129 * @param r The current request
130 * @param mtime The last modified time
131 * @return the latest rational time.
133 AP_DECLARE(apr_time_t) ap_rationalize_mtime(request_rec *r, apr_time_t mtime);
136 * Build the content-type that should be sent to the client from the
137 * content-type specified. The following rules are followed:
138 * - if type is NULL or "", return NULL (do not set content-type).
139 * - if charset adding is disabled, stop processing and return type.
140 * - then, if there are no parameters on type, add the default charset
142 * @param r The current request
143 * @param type The content type
144 * @return The content-type
146 AP_DECLARE(const char *) ap_make_content_type(request_rec *r,
150 * Precompile metadata structures used by ap_make_content_type()
151 * @param pool The pool to use for allocations
153 AP_DECLARE(void) ap_setup_make_content_type(apr_pool_t *pool);
156 * Construct an entity tag from the resource information. If it's a real
157 * file, build in some of the file characteristics.
158 * @param r The current request
159 * @param force_weak Force the entity tag to be weak - it could be modified
160 * again in as short an interval.
161 * @return The entity tag
163 AP_DECLARE(char *) ap_make_etag(request_rec *r, int force_weak);
166 * Set the E-tag outgoing header
167 * @param r The current request
169 AP_DECLARE(void) ap_set_etag(request_rec *r);
172 * Set the last modified time for the file being sent
173 * @param r The current request
175 AP_DECLARE(void) ap_set_last_modified(request_rec *r);
179 AP_CONDITION_NOMATCH,
185 * Tests conditional request rules for the If-Match header.
186 * @param r The current request
187 * @param headers The response headers to check against
188 * @return AP_CONDITION_NONE if the header is missing, AP_CONDITION_NOMATCH
189 * if the header does not match, AP_CONDITION_STRONG for a strong
190 * match. Weak matches are not permitted for the If-Match header.
192 AP_DECLARE(ap_condition_e) ap_condition_if_match(request_rec *r,
193 apr_table_t *headers);
196 * Tests conditional request rules for the If-Unmodified-Since header.
197 * @param r The current request
198 * @param headers The response headers to check against
199 * @return AP_CONDITION_NONE if the header is missing, AP_CONDITION_NOMATCH
200 * if the header does not match, AP_CONDITION_WEAK if a weak match
201 * was present and allowed by RFC2616, AP_CONDITION_STRONG for a
204 AP_DECLARE(ap_condition_e) ap_condition_if_unmodified_since(request_rec *r,
205 apr_table_t *headers);
208 * Tests conditional request rules for the If-None-Match header.
209 * @param r The current request
210 * @param headers The response headers to check against
211 * @return AP_CONDITION_NONE if the header is missing, AP_CONDITION_NOMATCH
212 * if the header does not match, AP_CONDITION_WEAK if a weak match
213 * was present and allowed by RFC2616, AP_CONDITION_STRONG for a
216 AP_DECLARE(ap_condition_e) ap_condition_if_none_match(request_rec *r,
217 apr_table_t *headers);
220 * Tests conditional request rules for the If-Modified-Since header.
221 * @param r The current request
222 * @param headers The response headers to check against
223 * @return AP_CONDITION_NONE if the header is missing, AP_CONDITION_NOMATCH
224 * if the header does not match, AP_CONDITION_WEAK if a weak match
225 * was present and allowed by RFC2616, AP_CONDITION_STRONG for a
228 AP_DECLARE(ap_condition_e) ap_condition_if_modified_since(request_rec *r,
229 apr_table_t *headers);
232 * Tests conditional request rules for the If-Range header.
233 * @param r The current request
234 * @param headers The response headers to check against
235 * @return AP_CONDITION_NONE if either the If-Range or Range header is
236 * missing, AP_CONDITION_NOMATCH if the header does not match,
237 * AP_CONDITION_STRONG for a strong match. Weak matches are not
238 * permitted for the If-Range header.
240 AP_DECLARE(ap_condition_e) ap_condition_if_range(request_rec *r,
241 apr_table_t *headers);
244 * Implements condition GET rules for HTTP/1.1 specification. This function
245 * inspects the client headers and determines if the response fulfills
246 * the requirements specified.
247 * @param r The current request
248 * @return OK if the response fulfills the condition GET rules, some
249 * other status code otherwise
251 AP_DECLARE(int) ap_meets_conditions(request_rec *r);
253 /* Other ways to send stuff at the client. All of these keep track
254 * of bytes_sent automatically. This indirection is intended to make
255 * it a little more painless to slide things like HTTP-NG packetization
256 * underneath the main body of the code later. In the meantime, it lets
257 * us centralize a bit of accounting (bytes_sent).
259 * These also return the number of bytes written by the call.
260 * They should only be called with a timeout registered, for obvious reaasons.
261 * (Ditto the send_header stuff).
265 * Send an entire file to the client, using sendfile if supported by the
267 * @param fd The file to send.
268 * @param r The current request
269 * @param offset Offset into the file to start sending.
270 * @param length Amount of data to send
271 * @param nbytes Amount of data actually sent
273 AP_DECLARE(apr_status_t) ap_send_fd(apr_file_t *fd, request_rec *r, apr_off_t offset,
274 apr_size_t length, apr_size_t *nbytes);
278 * Send an MMAP'ed file to the client
279 * @param mm The MMAP'ed file to send
280 * @param r The current request
281 * @param offset The offset into the MMAP to start sending
282 * @param length The amount of data to send
283 * @return The number of bytes sent
285 AP_DECLARE(apr_size_t) ap_send_mmap(apr_mmap_t *mm,
293 * Register a new request method, and return the offset that will be
294 * associated with that method.
296 * @param p The pool to create registered method numbers from.
297 * @param methname The name of the new method to register.
298 * @return An int value representing an offset into a bitmask.
300 AP_DECLARE(int) ap_method_register(apr_pool_t *p, const char *methname);
303 * Initialize the method_registry and allocate memory for it.
305 * @param p Pool to allocate memory for the registry from.
307 AP_DECLARE(void) ap_method_registry_init(apr_pool_t *p);
310 * This is a convenience macro to ease with checking a mask
311 * against a method name.
313 #define AP_METHOD_CHECK_ALLOWED(mask, methname) \
314 ((mask) & (AP_METHOD_BIT << ap_method_number_of((methname))))
317 * Create a new method list with the specified number of preallocated
318 * slots for extension methods.
320 * @param p Pointer to a pool in which the structure should be
322 * @param nelts Number of preallocated extension slots
323 * @return Pointer to the newly created structure.
325 AP_DECLARE(ap_method_list_t *) ap_make_method_list(apr_pool_t *p, int nelts);
331 * @param dest List to copy to
332 * @param src List to copy from
334 AP_DECLARE(void) ap_copy_method_list(ap_method_list_t *dest,
335 ap_method_list_t *src);
338 * Search for an HTTP method name in an ap_method_list_t structure, and
339 * return true if found.
341 * @param method String containing the name of the method to check.
342 * @param l Pointer to a method list, such as r->allowed_methods.
343 * @return 1 if method is in the list, otherwise 0
345 AP_DECLARE(int) ap_method_in_list(ap_method_list_t *l, const char *method);
348 * Add an HTTP method name to an ap_method_list_t structure if it isn't
351 * @param method String containing the name of the method to check.
352 * @param l Pointer to a method list, such as r->allowed_methods.
355 AP_DECLARE(void) ap_method_list_add(ap_method_list_t *l, const char *method);
358 * Remove an HTTP method name from an ap_method_list_t structure.
360 * @param l Pointer to a method list, such as r->allowed_methods.
361 * @param method String containing the name of the method to remove.
364 AP_DECLARE(void) ap_method_list_remove(ap_method_list_t *l,
368 * Reset a method list to be completely empty.
370 * @param l Pointer to a method list, such as r->allowed_methods.
373 AP_DECLARE(void) ap_clear_method_list(ap_method_list_t *l);
376 * Set the content type for this request (r->content_type).
377 * @param r The current request
378 * @param ct The new content type
379 * @warning This function must be called to set r->content_type in order
380 * for the AddOutputFilterByType directive to work correctly.
382 AP_DECLARE(void) ap_set_content_type(request_rec *r, const char *ct);
385 * Set the Accept-Ranges header for this response
386 * @param r The current request
388 AP_DECLARE(void) ap_set_accept_ranges(request_rec *r);
391 /* Hmmm... could macrofy these for now, and maybe forever, though the
392 * definitions of the macros would get a whole lot hairier.
396 * Output one character for this request
397 * @param c the character to output
398 * @param r the current request
399 * @return The number of bytes sent
401 AP_DECLARE(int) ap_rputc(int c, request_rec *r);
404 * Write a buffer for the current request
405 * @param buf The buffer to write
406 * @param nbyte The number of bytes to send from the buffer
407 * @param r The current request
408 * @return The number of bytes sent
410 AP_DECLARE(int) ap_rwrite(const void *buf, int nbyte, request_rec *r);
413 * Output a string for the current request
414 * @param str The string to output
415 * @param r The current request
416 * @return The number of bytes sent
417 * @note ap_rputs may be implemented as macro or inline function
419 static APR_INLINE int ap_rputs(const char *str, request_rec *r)
421 return ap_rwrite(str, (int)strlen(str), r);
425 * Write an unspecified number of strings to the request
426 * @param r The current request
427 * @param ... The strings to write
428 * @return The number of bytes sent
430 AP_DECLARE_NONSTD(int) ap_rvputs(request_rec *r,...)
434 * Output data to the client in a printf format
435 * @param r The current request
436 * @param fmt The format string
437 * @param vlist The arguments to use to fill out the format string
438 * @return The number of bytes sent
440 AP_DECLARE(int) ap_vrprintf(request_rec *r, const char *fmt, va_list vlist);
443 * Output data to the client in a printf format
444 * @param r The current request
445 * @param fmt The format string
446 * @param ... The arguments to use to fill out the format string
447 * @return The number of bytes sent
449 AP_DECLARE_NONSTD(int) ap_rprintf(request_rec *r, const char *fmt,...)
450 __attribute__((format(printf,2,3)));
453 * Flush all of the data for the current request to the client
454 * @param r The current request
455 * @return 0 on success, -1 if an error occurred
457 AP_DECLARE(int) ap_rflush(request_rec *r);
460 * Index used in custom_responses array for a specific error code
461 * (only use outside protocol.c is in getting them configured).
462 * @param status HTTP status code
463 * @return The index of the response
465 AP_DECLARE(int) ap_index_of_response(int status);
468 * Return the Status-Line for a given status code (excluding the
469 * HTTP-Version field). If an invalid or unknown status code is
470 * passed, "500 Internal Server Error" will be returned.
471 * @param status The HTTP status code
472 * @return The Status-Line
474 AP_DECLARE(const char *) ap_get_status_line(int status);
477 * Return the Status-Line for a given status code (excluding the
478 * HTTP-Version field). If an invalid status code is passed,
479 * "500 Internal Server Error" will be returned, whereas an unknown
480 * status will be returned like "xxx Status xxx".
481 * @param p The pool to allocate from when status is unknown
482 * @param status The HTTP status code
483 * @return The Status-Line
485 AP_DECLARE(const char *) ap_get_status_line_ex(apr_pool_t *p, int status);
487 /* Reading a block of data from the client connection (e.g., POST arg) */
490 * Setup the client to allow Apache to read the request body.
491 * @param r The current request
492 * @param read_policy How the server should interpret a chunked
493 * transfer-encoding. One of: <pre>
494 * REQUEST_NO_BODY Send 413 error if message has any body
495 * REQUEST_CHUNKED_ERROR Send 411 error if body without Content-Length
496 * REQUEST_CHUNKED_DECHUNK If chunked, remove the chunks for me.
498 * @return either OK or an error code
500 AP_DECLARE(int) ap_setup_client_block(request_rec *r, int read_policy);
503 * Determine if the client has sent any data. This also sends a
504 * 100 Continue response to HTTP/1.1 clients, so modules should not be called
505 * until the module is ready to read content.
506 * @warning Never call this function more than once.
507 * @param r The current request
508 * @return 0 if there is no message to read, 1 otherwise
510 AP_DECLARE(int) ap_should_client_block(request_rec *r);
513 * Call this in a loop. It will put data into a buffer and return the length
515 * @param r The current request
516 * @param buffer The buffer in which to store the data
517 * @param bufsiz The size of the buffer
518 * @return Number of bytes inserted into the buffer. When done reading, 0
519 * if EOF, or -1 if there was an error
521 AP_DECLARE(long) ap_get_client_block(request_rec *r, char *buffer, apr_size_t bufsiz);
524 * Map specific APR codes returned by the filter stack to HTTP error
525 * codes, or the default status code provided. Use it as follows:
527 * return ap_map_http_request_error(rv, HTTP_BAD_REQUEST);
529 * If the filter has already handled the error, AP_FILTER_ERROR will
530 * be returned, which is cleanly passed through.
532 * These mappings imply that the filter stack is reading from the
533 * downstream client, the proxy will map these codes differently.
534 * @param rv APR status code
535 * @param status Default HTTP code should the APR code not be recognised
536 * @return Mapped HTTP status code
538 AP_DECLARE(int) ap_map_http_request_error(apr_status_t rv, int status);
541 * In HTTP/1.1, any method can have a body. However, most GET handlers
542 * wouldn't know what to do with a request body if they received one.
543 * This helper routine tests for and reads any message body in the request,
544 * simply discarding whatever it receives. We need to do this because
545 * failing to read the request body would cause it to be interpreted
546 * as the next request on a persistent connection.
547 * @param r The current request
548 * @return error status if request is malformed, OK otherwise
550 AP_DECLARE(int) ap_discard_request_body(request_rec *r);
553 * Setup the output headers so that the client knows how to authenticate
554 * itself the next time, if an authentication request failed.
555 * @param r The current request
557 AP_DECLARE(void) ap_note_auth_failure(request_rec *r);
560 * @deprecated @see ap_note_auth_failure
562 AP_DECLARE(void) ap_note_basic_auth_failure(request_rec *r);
565 * @deprecated @see ap_note_auth_failure
567 AP_DECLARE(void) ap_note_digest_auth_failure(request_rec *r);
570 * This hook allows modules to add support for a specific auth type to
571 * ap_note_auth_failure
572 * @param r the current request
573 * @param auth_type the configured auth_type
574 * @return OK, DECLINED
576 AP_DECLARE_HOOK(int, note_auth_failure, (request_rec *r, const char *auth_type))
579 * Get the password from the request headers. This function has multiple side
580 * effects due to its prior use in the old authentication framework, including
581 * setting r->user (which is supposed to indicate that the user in question has
582 * been authenticated for the current request).
584 * Modules which call ap_get_basic_auth_pw() during the authentication phase
585 * MUST either immediately authenticate the user after the call, or else stop
586 * the request immediately with an error response, to avoid incorrectly
587 * authenticating the current request. (See CVE-2017-3167.) The replacement
588 * ap_get_basic_auth_components() API should be preferred.
590 * @deprecated @see ap_get_basic_auth_components
591 * @param r The current request
592 * @param pw The password as set in the headers
593 * @return 0 (OK) if it set the 'pw' argument (and assured
594 * a correct value in r->user); otherwise it returns
595 * an error code, either HTTP_INTERNAL_SERVER_ERROR if things are
596 * really confused, HTTP_UNAUTHORIZED if no authentication at all
597 * seemed to be in use, or DECLINED if there was authentication but
598 * it wasn't Basic (in which case, the caller should presumably
601 AP_DECLARE(int) ap_get_basic_auth_pw(request_rec *r, const char **pw);
603 #define AP_GET_BASIC_AUTH_PW_NOTE "AP_GET_BASIC_AUTH_PW_NOTE"
606 * Get the username and/or password from the request's Basic authentication
607 * headers. Unlike ap_get_basic_auth_pw(), calling this function has no side
608 * effects on the passed request_rec.
610 * @param r The current request
611 * @param username If not NULL, set to the username sent by the client
612 * @param password If not NULL, set to the password sent by the client
613 * @return APR_SUCCESS if the credentials were successfully parsed and returned;
614 * APR_EINVAL if there was no authentication header sent or if the
615 * client was not using the Basic authentication scheme. username and
616 * password are unchanged on failure.
618 AP_DECLARE(apr_status_t) ap_get_basic_auth_components(const request_rec *r,
619 const char **username,
620 const char **password);
623 * parse_uri: break apart the uri
624 * @warning Side Effects:
625 * @li sets r->args to rest after '?' (or NULL if no '?')
626 * @li sets r->uri to request uri (without r->args part)
627 * @li sets r->hostname (if not set already) from request (scheme://host:port)
628 * @param r The current request
629 * @param uri The uri to break apart
631 AP_CORE_DECLARE(void) ap_parse_uri(request_rec *r, const char *uri);
633 #define AP_GETLINE_FOLD 1 /* Whether to merge continuation lines */
634 #define AP_GETLINE_CRLF 2 /*Whether line ends must be in the form CR LF */
637 * Get the next line of input for the request
638 * @param s The buffer into which to read the line
639 * @param n The size of the buffer
640 * @param r The request
641 * @param flags Bit flag of multiple parsing options
642 * AP_GETLINE_FOLD Whether to merge continuation lines
643 * AP_GETLINE_CRLF Whether line ends must be in the form CR LF
644 * @return The length of the line, if successful
645 * n, if the line is too big to fit in the buffer
646 * -1 for miscellaneous errors
648 AP_DECLARE(int) ap_getline(char *s, int n, request_rec *r, int flags);
651 * Get the next line of input for the request
653 * Note: on ASCII boxes, ap_rgetline is a macro which simply calls
654 * ap_rgetline_core to get the line of input.
656 * on EBCDIC boxes, ap_rgetline is a wrapper function which
657 * translates ASCII protocol lines to the local EBCDIC code page
658 * after getting the line of input.
660 * @param s Pointer to the pointer to the buffer into which the line
661 * should be read; if *s==NULL, a buffer of the necessary size
662 * to hold the data will be allocated from the request pool
663 * @param n The size of the buffer
664 * @param read The length of the line.
665 * @param r The request
666 * @param flags Bit flag of multiple parsing options
667 * AP_GETLINE_FOLD Whether to merge continuation lines
668 * AP_GETLINE_CRLF Whether line ends must be in the form CR LF
669 * @param bb Working brigade to use when reading buckets
670 * @return APR_SUCCESS, if successful
671 * APR_ENOSPC, if the line is too big to fit in the buffer
672 * Other errors where appropriate
674 #if APR_CHARSET_EBCDIC
675 AP_DECLARE(apr_status_t) ap_rgetline(char **s, apr_size_t n,
677 request_rec *r, int flags,
678 apr_bucket_brigade *bb);
679 #else /* ASCII box */
680 #define ap_rgetline(s, n, read, r, fold, bb) \
681 ap_rgetline_core((s), (n), (read), (r), (fold), (bb))
684 /** @see ap_rgetline */
685 AP_DECLARE(apr_status_t) ap_rgetline_core(char **s, apr_size_t n,
687 request_rec *r, int flags,
688 apr_bucket_brigade *bb);
691 * Get the method number associated with the given string, assumed to
692 * contain an HTTP method. Returns M_INVALID if not recognized.
693 * @param method A string containing a valid HTTP method
694 * @return The method number
696 AP_DECLARE(int) ap_method_number_of(const char *method);
699 * Get the method name associated with the given internal method
700 * number. Returns NULL if not recognized.
701 * @param p A pool to use for temporary allocations.
702 * @param methnum An integer value corresponding to an internal method number
703 * @return The name corresponding to the method number
705 AP_DECLARE(const char *) ap_method_name_of(apr_pool_t *p, int methnum);
710 * pre_read_request --- run right before read_request_line(),
711 * and not run during any subrequests.
714 * This hook allows modules to affect the request or connection immediately before
715 * the request has been read, and before any other phases have been processes.
716 * @param r The current request of the soon-to-be-read request
717 * @param c The connection
720 AP_DECLARE_HOOK(void,pre_read_request,(request_rec *r, conn_rec *c))
723 * post_read_request --- run right after read_request or internal_redirect,
724 * and not run during any subrequests.
727 * This hook allows modules to affect the request immediately after the request
728 * has been read, and before any other phases have been processes. This allows
729 * modules to make decisions based upon the input header fields
730 * @param r The current request
731 * @return OK or DECLINED
733 AP_DECLARE_HOOK(int,post_read_request,(request_rec *r))
736 * This hook allows modules to perform any module-specific logging activities
737 * over and above the normal server things.
738 * @param r The current request
739 * @return OK, DECLINED, or HTTP_...
741 AP_DECLARE_HOOK(int,log_transaction,(request_rec *r))
744 * This hook allows modules to retrieve the http scheme for a request. This
745 * allows Apache modules to easily extend the schemes that Apache understands
746 * @param r The current request
747 * @return The http scheme from the request
749 AP_DECLARE_HOOK(const char *,http_scheme,(const request_rec *r))
752 * Return the default port from the current request
753 * @param r The current request
754 * @return The current port
756 AP_DECLARE_HOOK(apr_port_t,default_port,(const request_rec *r))
759 #define AP_PROTOCOL_HTTP1 "http/1.1"
762 * Determine the list of protocols available for a connection/request. This may
763 * be collected with or without any request sent, in which case the request is
764 * NULL. Or it may be triggered by the request received, e.g. through the
767 * This hook will be run whenever protocols are being negotiated (ALPN as
768 * one example). It may also be invoked at other times, e.g. when the server
769 * wants to advertise protocols it is capable of switching to.
771 * The identifiers for protocols are taken from the TLS extension type ALPN:
772 * https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xml
774 * If no protocols are added to the proposals, the server not perform any
775 * switch. If the protocol selected from the proposals is the protocol
776 * already in place, also no protocol switch will be invoked.
778 * The client may already have announced the protocols it is willing to
779 * accept. These will then be listed as offers. This parameter may also
780 * be NULL, indicating that offers from the client are not known and
781 * the hooks should propose all protocols that are valid for the
782 * current connection/request.
784 * All hooks are run, unless one returns an error. Proposals may contain
785 * duplicates. The order in which proposals are added is usually ignored.
787 * @param c The current connection
788 * @param r The current request or NULL
789 * @param s The server/virtual host selected
790 * @param offers A list of protocol identifiers offered by the client or
791 * NULL to indicated that the hooks are free to propose
792 * @param proposals The list of protocol identifiers proposed by the hooks
793 * @return OK or DECLINED
795 AP_DECLARE_HOOK(int,protocol_propose,(conn_rec *c, request_rec *r,
797 const apr_array_header_t *offers,
798 apr_array_header_t *proposals))
801 * Perform a protocol switch on the connection. The exact requirements for
802 * that depend on the protocol in place and the one switched to. The first
803 * protocol module to handle the switch is the last module run.
805 * For a connection level switch (r == NULL), the handler must on return
806 * leave the conn_rec in a state suitable for processing the switched
807 * protocol, e.g. correct filters in place.
809 * For a request triggered switch (r != NULL), the protocol switch is done
810 * before the response is sent out. When switching from "http/1.1" via Upgrade
811 * header, the 101 intermediate response will have been sent. The
812 * hook needs then to process the connection until it can be closed. Which
813 * the server will enforce on hook return.
814 * Any error the hook might encounter must already be sent by the hook itself
815 * to the client in whatever form the new protocol requires.
817 * @param c The current connection
818 * @param r The current request or NULL
819 * @param s The server/virtual host selected
820 * @param choices A list of protocol identifiers, normally the client's wishes
821 * @param proposals the list of protocol identifiers proposed by the hooks
822 * @return OK or DECLINED
824 AP_DECLARE_HOOK(int,protocol_switch,(conn_rec *c, request_rec *r,
826 const char *protocol))
829 * Return the protocol used on the connection. Modules implementing
830 * protocol switching must register here and return the correct protocol
831 * identifier for connections they switched.
833 * To find out the protocol for the current connection, better call
834 * @see ap_get_protocol which internally uses this hook.
836 * @param c The current connection
837 * @return The identifier of the protocol in place or NULL
839 AP_DECLARE_HOOK(const char *,protocol_get,(const conn_rec *c))
842 * Get the protocols that the connection and optional request may
843 * upgrade to - besides the protocol currently active on the connection. These
844 * values may be used to announce to a client what choices it has.
846 * If report_all == 0, only protocols more preferable than the one currently
847 * being used, are reported. Otherwise, all available protocols beside the
848 * current one are being reported.
850 * @param c The current connection
851 * @param r The current request or NULL
852 * @param s The server/virtual host selected or NULL
853 * @param report_all include also protocols less preferred than the current one
854 * @param pupgrades on return, possible protocols to upgrade to in descending order
855 * of preference. Maybe NULL if none are available.
857 AP_DECLARE(apr_status_t) ap_get_protocol_upgrades(conn_rec *c, request_rec *r,
858 server_rec *s, int report_all,
859 const apr_array_header_t **pupgrades);
862 * Select a protocol for the given connection and optional request. Will return
863 * the protocol identifier selected which may be the protocol already in place
864 * on the connection. The selected protocol will be NULL if non of the given
865 * choices could be agreed upon (e.g. no proposal as made).
867 * A special case is where the choices itself is NULL (instead of empty). In
868 * this case there are no restrictions imposed on protocol selection.
870 * @param c The current connection
871 * @param r The current request or NULL
872 * @param s The server/virtual host selected
873 * @param choices A list of protocol identifiers, normally the client's wishes
874 * @return The selected protocol or NULL if no protocol could be agreed upon
876 AP_DECLARE(const char *) ap_select_protocol(conn_rec *c, request_rec *r,
878 const apr_array_header_t *choices);
881 * Perform the actual protocol switch. The protocol given must have been
882 * selected before on the very same connection and request pair.
884 * @param c The current connection
885 * @param r The current request or NULL
886 * @param s The server/virtual host selected
887 * @param protocol the protocol to switch to
888 * @return APR_SUCCESS, if caller may continue processing as usual
889 * APR_EOF, if caller needs to stop processing the connection
890 * APR_EINVAL, if the protocol is already in place
891 * APR_NOTIMPL, if no module performed the switch
892 * Other errors where appropriate
894 AP_DECLARE(apr_status_t) ap_switch_protocol(conn_rec *c, request_rec *r,
896 const char *protocol);
899 * Call the protocol_get hook to determine the protocol currently in use
900 * for the given connection.
902 * Unless another protocol has been switch to, will default to
903 * @see AP_PROTOCOL_HTTP1 and modules implementing a new protocol must
904 * report a switched connection via the protocol_get hook.
906 * @param c The connection to determine the protocol for
907 * @return the protocol in use, never NULL
909 AP_DECLARE(const char *) ap_get_protocol(conn_rec *c);
912 * Check if the given protocol is an allowed choice on the given
913 * combination of connection, request and server.
915 * When server is NULL, it is taken from request_rec, unless
916 * request_rec is NULL. Then it is taken from the connection base
919 * @param c The current connection
920 * @param r The current request or NULL
921 * @param s The server/virtual host selected or NULL
922 * @param protocol the protocol to switch to
923 * @return != 0 iff protocol is allowed
925 AP_DECLARE(int) ap_is_allowed_protocol(conn_rec *c, request_rec *r,
926 server_rec *s, const char *protocol);
928 /** @see ap_bucket_type_error */
929 typedef struct ap_bucket_error ap_bucket_error;
932 * @struct ap_bucket_error
933 * @brief A bucket referring to an HTTP error
935 * This bucket can be passed down the filter stack to indicate that an
936 * HTTP error occurred while running a filter. In order for this bucket
937 * to be used successfully, it MUST be sent as the first bucket in the
938 * first brigade to be sent from a given filter.
940 struct ap_bucket_error {
941 /** Number of buckets using this memory */
942 apr_bucket_refcount refcount;
943 /** The error code */
945 /** The error string */
949 /** @see ap_bucket_type_error */
950 AP_DECLARE_DATA extern const apr_bucket_type_t ap_bucket_type_error;
953 * Determine if a bucket is an error bucket
954 * @param e The bucket to inspect
955 * @return true or false
957 #define AP_BUCKET_IS_ERROR(e) (e->type == &ap_bucket_type_error)
960 * Make the bucket passed in an error bucket
961 * @param b The bucket to make into an error bucket
962 * @param error The HTTP error code to put in the bucket.
963 * @param buf An optional error string to put in the bucket.
964 * @param p A pool to allocate out of.
965 * @return The new bucket, or NULL if allocation failed
967 AP_DECLARE(apr_bucket *) ap_bucket_error_make(apr_bucket *b, int error,
968 const char *buf, apr_pool_t *p);
971 * Create a bucket referring to an HTTP error.
972 * @param error The HTTP error code to put in the bucket.
973 * @param buf An optional error string to put in the bucket.
974 * @param p A pool to allocate the error string out of.
975 * @param list The bucket allocator from which to allocate the bucket
976 * @return The new bucket, or NULL if allocation failed
978 AP_DECLARE(apr_bucket *) ap_bucket_error_create(int error, const char *buf,
980 apr_bucket_alloc_t *list);
982 AP_DECLARE_NONSTD(apr_status_t) ap_byterange_filter(ap_filter_t *f, apr_bucket_brigade *b);
983 AP_DECLARE_NONSTD(apr_status_t) ap_http_header_filter(ap_filter_t *f, apr_bucket_brigade *b);
984 AP_DECLARE_NONSTD(apr_status_t) ap_content_length_filter(ap_filter_t *,
985 apr_bucket_brigade *);
986 AP_DECLARE_NONSTD(apr_status_t) ap_old_write_filter(ap_filter_t *f, apr_bucket_brigade *b);
989 * Sett up the protocol fields for subsidiary requests
990 * @param rnew New Sub Request
991 * @param r current request
993 AP_DECLARE(void) ap_set_sub_req_protocol(request_rec *rnew, const request_rec *r);
996 * A wrapup function to keep the internal accounting straight.
997 * Indicates that there is no more content coming.
998 * @param sub_r Subrequest that is now compete
1000 AP_DECLARE(void) ap_finalize_sub_req_protocol(request_rec *sub_r);
1003 * Send an interim (HTTP 1xx) response immediately.
1004 * @param r The request
1005 * @param send_headers Whether to send&clear headers in r->headers_out
1007 AP_DECLARE(void) ap_send_interim_response(request_rec *r, int send_headers);
1013 #endif /* !APACHE_HTTP_PROTOCOL_H */