/* 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 mod_ssl.h
 * @brief SSL extension module for Apache
 *
 * @defgroup MOD_SSL mod_ssl
 * @ingroup  APACHE_MODS
 * @{
 */

#ifndef __MOD_SSL_H__
#define __MOD_SSL_H__

#include "httpd.h"
#include "apr_optional.h"

/* Create a set of SSL_DECLARE(type), SSL_DECLARE_NONSTD(type) and
 * SSL_DECLARE_DATA with appropriate export and import tags for the platform
 */
#if !defined(WIN32)
#define SSL_DECLARE(type)            type
#define SSL_DECLARE_NONSTD(type)     type
#define SSL_DECLARE_DATA
#elif defined(SSL_DECLARE_STATIC)
#define SSL_DECLARE(type)            type __stdcall
#define SSL_DECLARE_NONSTD(type)     type
#define SSL_DECLARE_DATA
#elif defined(SSL_DECLARE_EXPORT)
#define SSL_DECLARE(type)            __declspec(dllexport) type __stdcall
#define SSL_DECLARE_NONSTD(type)     __declspec(dllexport) type
#define SSL_DECLARE_DATA             __declspec(dllexport)
#else
#define SSL_DECLARE(type)            __declspec(dllimport) type __stdcall
#define SSL_DECLARE_NONSTD(type)     __declspec(dllimport) type
#define SSL_DECLARE_DATA             __declspec(dllimport)
#endif

/** The ssl_var_lookup() optional function retrieves SSL environment
 * variables. */
APR_DECLARE_OPTIONAL_FN(char *, ssl_var_lookup,
                        (apr_pool_t *, server_rec *,
                         conn_rec *, request_rec *,
                         char *));

/** The ssl_ext_list() optional function attempts to build an array
 * of all the values contained in the named X.509 extension. The
 * returned array will be created in the supplied pool.
 * The client certificate is used if peer is non-zero; the server
 * certificate is used otherwise.
 * Extension specifies the extensions to use as a string. This can be
 * one of the "known" long or short names, or a numeric OID,
 * e.g. "1.2.3.4", 'nsComment' and 'DN' are all valid.
 * A pointer to an apr_array_header_t structure is returned if at
 * least one matching extension is found, NULL otherwise.
 */
APR_DECLARE_OPTIONAL_FN(apr_array_header_t *, ssl_ext_list,
                        (apr_pool_t *p, conn_rec *c, int peer,
                         const char *extension));

/** An optional function which returns non-zero if the given connection
 * is using SSL/TLS. */
APR_DECLARE_OPTIONAL_FN(int, ssl_is_https, (conn_rec *));

/** A function that returns the TLS channel binding data as per
 * RFC5929.  A buffer containing the Channel Binding Token for the
 * given type will be allocated from the pool and returned to the
 * caller, along with the size.  Returns APR_SUCCESS on success; buf
 * and size are not adjusted on error. */
APR_DECLARE_OPTIONAL_FN(apr_status_t, ssl_get_tls_cb,
                        (apr_pool_t *p, conn_rec *c, const char *type,
                         unsigned char **buf, apr_size_t *size));

/** The ssl_proxy_enable() and ssl_engine_disable() optional functions
 * are used by mod_proxy to enable use of SSL for outgoing
 * connections. */

APR_DECLARE_OPTIONAL_FN(int, ssl_proxy_enable, (conn_rec *));

APR_DECLARE_OPTIONAL_FN(int, ssl_engine_disable, (conn_rec *));

/** The npn_advertise_protos callback allows another modules to add
 * entries to the list of protocol names advertised by the server
 * during the Next Protocol Negotiation (NPN) portion of the SSL
 * handshake.  The callback is given the connection and an APR array;
 * it should push one or more char*'s pointing to NUL-terminated
 * strings (such as "http/1.1" or "spdy/2") onto the array and return
 * OK.  To prevent further processing of (other modules') callbacks,
 * return DONE. */
typedef int (*ssl_npn_advertise_protos)(conn_rec *connection, 
                                        apr_array_header_t *protos);

/** The npn_proto_negotiated callback allows other modules to discover
 * the name of the protocol that was chosen during the Next Protocol
 * Negotiation (NPN) portion of the SSL handshake.  Note that this may
 * be the empty string (in which case modules should probably assume
 * HTTP), or it may be a protocol that was never even advertised by
 * the server.  The callback is given the connection, a
 * non-NUL-terminated string containing the protocol name, and the
 * length of the string; it should do something appropriate
 * (i.e. insert or remove filters) and return OK.  To prevent further
 * processing of (other modules') callbacks, return DONE. */
typedef int (*ssl_npn_proto_negotiated)(conn_rec *connection, 
                                        const char *proto_name,
                                        apr_size_t proto_name_len);

/* An optional function which can be used to register a pair of
 * callbacks for NPN handling.  This optional function should be
 * invoked from a pre_connection hook which runs *after* mod_ssl.c's
 * pre_connection hook.  The function returns OK if the callbacks are
 * register, or DECLINED otherwise (for example if mod_ssl does not
 * support NPN).  */
APR_DECLARE_OPTIONAL_FN(int, modssl_register_npn, (conn_rec *conn, 
                                                   ssl_npn_advertise_protos advertisefn,
                                                   ssl_npn_proto_negotiated negotiatedfn));

#endif /* __MOD_SSL_H__ */
/** @} */
