/* Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (the "License"); you may not use this file except in compliance with

 * the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

/**

 * @file  util_fcgi.h

 * @brief FastCGI protocol defitions and support routines

 *

 * @defgroup APACHE_CORE_FASTCGI FastCGI Tools

 * @ingroup  APACHE_CORE

 * @{

 */

#ifndef APACHE_UTIL_FCGI_H

#define APACHE_UTIL_FCGI_H

#ifdef __cplusplus

extern "C" {

#endif

#include "httpd.h"

/**

 * @brief A structure that represents the fixed header fields

 * at the beginning of a "FastCGI record" (i.e., the data prior

 * to content data and padding).

 */

typedef struct {

    /** See values for version, below */

    unsigned char version;

    /** See values for type, below */

    unsigned char type;

    /** request id, in two parts */

    unsigned char requestIdB1;

    unsigned char requestIdB0;

    /** content length, in two parts */

    unsigned char contentLengthB1;

    unsigned char contentLengthB0;

    /** padding length */

    unsigned char paddingLength;

    /** 8-bit reserved field */

    unsigned char reserved;

} ap_fcgi_header;

/*

 * Number of bytes in the header portion of a FastCGI record

 * (i.e., ap_fcgi_header structure).  Future versions of the

 * protocol may increase the size.

 */

#define AP_FCGI_HEADER_LEN  8

/*

 * Maximum number of bytes in the content portion of a FastCGI record.

 */

#define AP_FCGI_MAX_CONTENT_LEN 65535

/**

 * Possible values for the version field of ap_fcgi_header

 */

#define AP_FCGI_VERSION_1 1

/**

 * Possible values for the type field of ap_fcgi_header

 */

#define AP_FCGI_BEGIN_REQUEST       1

#define AP_FCGI_ABORT_REQUEST       2

#define AP_FCGI_END_REQUEST         3

#define AP_FCGI_PARAMS              4

#define AP_FCGI_STDIN               5

#define AP_FCGI_STDOUT              6

#define AP_FCGI_STDERR              7

#define AP_FCGI_DATA                8

#define AP_FCGI_GET_VALUES          9

#define AP_FCGI_GET_VALUES_RESULT  10

#define AP_FCGI_UNKNOWN_TYPE       11

#define AP_FCGI_MAXTYPE (AP_FCGI_UNKNOWN_TYPE)

/**

 * Offsets of the various fields of ap_fcgi_header

 */

#define AP_FCGI_HDR_VERSION_OFFSET         0

#define AP_FCGI_HDR_TYPE_OFFSET            1

#define AP_FCGI_HDR_REQUEST_ID_B1_OFFSET   2

#define AP_FCGI_HDR_REQUEST_ID_B0_OFFSET   3

#define AP_FCGI_HDR_CONTENT_LEN_B1_OFFSET  4

#define AP_FCGI_HDR_CONTENT_LEN_B0_OFFSET  5

#define AP_FCGI_HDR_PADDING_LEN_OFFSET     6

#define AP_FCGI_HDR_RESERVED_OFFSET        7

/**

 * @brief This represents the content data of the FastCGI record when

 * the type is AP_FCGI_BEGIN_REQUEST.

 */

typedef struct {

    /**

     * role, in two parts

     * See values for role, below

     */

    unsigned char roleB1;

    unsigned char roleB0;

    /**

     * flags

     * See values for flags bits, below

     */

    unsigned char flags;

    /** reserved */

    unsigned char reserved[5];

} ap_fcgi_begin_request_body;

/*

 * Values for role component of ap_fcgi_begin_request_body

 */

#define AP_FCGI_RESPONDER  1

#define AP_FCGI_AUTHORIZER 2

#define AP_FCGI_FILTER     3

/*

 * Values for flags bits of ap_fcgi_begin_request_body

 */

#define AP_FCGI_KEEP_CONN  1  /* otherwise the application closes */

/**

 * Offsets of the various fields of ap_fcgi_begin_request_body

 */

#define AP_FCGI_BRB_ROLEB1_OFFSET       0

#define AP_FCGI_BRB_ROLEB0_OFFSET       1

#define AP_FCGI_BRB_FLAGS_OFFSET        2

#define AP_FCGI_BRB_RESERVED0_OFFSET    3

#define AP_FCGI_BRB_RESERVED1_OFFSET    4

#define AP_FCGI_BRB_RESERVED2_OFFSET    5

#define AP_FCGI_BRB_RESERVED3_OFFSET    6

#define AP_FCGI_BRB_RESERVED4_OFFSET    7

/**

 * Pack ap_fcgi_header

 * @param h The header to read from

 * @param a The array to write to, of size AP_FCGI_HEADER_LEN

 */

AP_DECLARE(void) ap_fcgi_header_to_array(ap_fcgi_header *h,

                                         unsigned char a[]);

/**

 * Unpack header of FastCGI record into ap_fcgi_header

 * @param h The header to write to

 * @param a The array to read from, of size AP_FCGI_HEADER_LEN

 */

AP_DECLARE(void) ap_fcgi_header_from_array(ap_fcgi_header *h,

                                           unsigned char a[]);

/**

 * Unpack header of FastCGI record into individual fields

 * @param version The version, on output

 * @param type The type, on output

 * @param request_id The request id, on output

 * @param content_len The content length, on output

 * @param padding_len The amount of padding following the content, on output

 * @param a The array to read from, of size AP_FCGI_HEADER_LEN

 */

AP_DECLARE(void) ap_fcgi_header_fields_from_array(unsigned char *version,

                                                  unsigned char *type,

                                                  apr_uint16_t *request_id,

                                                  apr_uint16_t *content_len,

                                                  unsigned char *padding_len,

                                                  unsigned char a[]);

/**

 * Pack ap_fcgi_begin_request_body

 * @param h The begin-request body to read from

 * @param a The array to write to, of size AP_FCGI_HEADER_LEN

 */

AP_DECLARE(void) ap_fcgi_begin_request_body_to_array(ap_fcgi_begin_request_body *h,

                                                     unsigned char a[]);

/**

 * Fill in a FastCGI request header with the required field values.

 * @param header The header to fill in

 * @param type The type of record

 * @param request_id The request id

 * @param content_len The amount of content which follows the header

 * @param padding_len The amount of padding which follows the content

 *

 * The header array must be at least AP_FCGI_HEADER_LEN bytes long.

 */

AP_DECLARE(void) ap_fcgi_fill_in_header(ap_fcgi_header *header,

                                        unsigned char type,

                                        apr_uint16_t request_id,

                                        apr_uint16_t content_len,

                                        unsigned char padding_len);

/**

 * Fill in a FastCGI begin request body with the required field values.

 * @param brb The begin-request-body to fill in

 * @param role AP_FCGI_RESPONDER or other roles

 * @param flags 0 or a combination of flags like AP_FCGI_KEEP_CONN

 */

AP_DECLARE(void) ap_fcgi_fill_in_request_body(ap_fcgi_begin_request_body *brb,

                                              int role,

                                              unsigned char flags);

/**

 * Compute the buffer size needed to encode the next portion of

 * the provided environment table.

 * @param env The environment table

 * @param maxlen The maximum buffer size allowable, capped at 

 * AP_FCGI_MAX_CONTENT_LEN.

 * @param starting_elem On input, the next element of the table array

 * to process in this FastCGI record.  On output, the next element to

 * process on the *next* FastCGI record.

 * @return Size of buffer needed to encode the next part, or 0

 * if no more can be encoded.  When 0 is returned: If starting_elem

 * has reached the end of the table array, all has been encoded;

 * otherwise, the next envvar can't be encoded within the specified

 * limit.

 * @note If an envvar can't be encoded within the specified limit,

 * the caller can log a warning and increment starting_elem and try 

 * again or increase the limit or fail, as appropriate for the module.

 */

AP_DECLARE(apr_size_t) ap_fcgi_encoded_env_len(apr_table_t *env,

                                               apr_size_t maxlen,

                                               int *starting_elem);

/**

 * Encode the next portion of the provided environment table using

 * a buffer previously allocated.

 * @param r The request, for logging

 * @param env The environment table

 * @param buffer A buffer to contain the encoded environment table

 * @param buflen The length of the buffer, previously computed by

 * ap_fcgi_encoded_env_len().

 * @param starting_elem On input, the next element of the table array

 * to process in this FastCGI record.  On output, the next element to

 * process on the *next* FastCGI record.

 * @return APR_SUCCESS if a section could be encoded or APR_ENOSPC

 * otherwise.

 * @note The output starting_elem from ap_fcgi_encoded_env_len

 * shouldn't be used as input to ap_fcgi_encode_env when building the

 * same FastCGI record.

 */

AP_DECLARE(apr_status_t) ap_fcgi_encode_env(request_rec *r,

                                            apr_table_t *env,

                                            void *buffer,

                                            apr_size_t buflen,

                                            int *starting_elem);

/**

 * String forms for the value of the FCGI_ROLE envvar

 */

#define AP_FCGI_RESPONDER_STR   "RESPONDER"

#define AP_FCGI_AUTHORIZER_STR  "AUTHORIZER"

#define AP_FCGI_FILTER_STR      "FILTER"

/**

 * FastCGI implementations that implement the AUTHORIZER role

 * for Apache httpd and allow the application to participate in

 * any of the Apache httpd AAA phases typically set the variable

 * FCGI_APACHE_ROLE to one of these strings to indicate the

 * specific AAA phase.

 */

#define AP_FCGI_APACHE_ROLE_AUTHENTICATOR_STR  "AUTHENTICATOR"

#define AP_FCGI_APACHE_ROLE_AUTHORIZER_STR     "AUTHORIZER"

#define AP_FCGI_APACHE_ROLE_ACCESS_CHECKER_STR "ACCESS_CHECKER"

#ifdef __cplusplus

}

#endif

#endif  /* !APACHE_UTIL_FCGI_H */

/** @} */