/* An implementation of the nsd interface for OpenSSL.
 *
 * Copyright 2018-2021 Adiscon GmbH.
 * Author: Andre Lorbach
 *
 * This file is part of the rsyslog runtime library.
 *
 * Licensed 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
 *       -or-
 *       see COPYING.ASL20 in the source distribution
 *
 * 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.
 */

#ifndef INCLUDED_NSD_OSSL_H
#define INCLUDED_NSD_OSSL_H

#include "nsd.h"

#define NSD_OSSL_MAX_RCVBUF 16 * 1024 + 1/* TLS RFC 8449: max size of buffer for message reception */

typedef enum {
	osslRtry_None = 0,	/**< no call needs to be retried */
	osslRtry_handshake = 1,
	osslRtry_recv = 2
} osslRtryCall_t;		/**< IDs of calls that needs to be retried */

typedef enum {
	osslServer = 0,		/**< Server SSL Object */
	osslClient = 1		/**< Client SSL Object */
} osslSslState_t;


typedef nsd_if_t nsd_ossl_if_t; /* we just *implement* this interface */

/* the nsd_ossl object */
struct nsd_ossl_s {
	BEGINobjInstance;	/* Data to implement generic object - MUST be the first data element! */
	nsd_t *pTcp;		/**< our aggregated nsd_ptcp data */
	uchar *pszConnectHost;	/**< hostname used for connect - may be used to
					authenticate peer if no other name given */
	int iMode;		/* 0 - plain tcp, 1 - TLS */
	int bAbortConn;		/* if set, abort conncection (fatal error had happened) */
	const uchar *pszCAFile;
	const uchar *pszKeyFile;
	const uchar *pszCertFile;
	enum {
		OSSL_AUTH_CERTNAME = 0,
		OSSL_AUTH_CERTFINGERPRINT = 1,
		OSSL_AUTH_CERTVALID = 2,
		OSSL_AUTH_CERTANON = 3
	} authMode;
	enum {
		OSSL_EXPIRED_PERMIT = 0,
		OSSL_EXPIRED_DENY = 1,
		OSSL_EXPIRED_WARN = 2
	} permitExpiredCerts;
	osslRtryCall_t rtryCall;/**< what must we retry? */
	int rtryOsslErr;	/**< store ssl error code into like SSL_ERROR_WANT_READ or SSL_ERROR_WANT_WRITE */
	int bIsInitiator;	/**< 0 if socket is the server end (listener), 1 if it is the initiator */
	int bHaveSess;		/* as we don't know exactly which gnutls_session values
					are invalid, we use this one to flag whether or
					not we are in a session (same as -1 for a socket
					meaning no sess) */
	int bReportAuthErr;	/* only the first auth error is to be reported, this var triggers it. Initially, it is
				 * set to 1 and changed to 0 after the first report. It is changed back to 1 after
				 * one successful authentication. */
	permittedPeers_t *pPermPeers; /* permitted peers */
	uchar *gnutlsPriorityString;	/* gnutls priority string */
	int DrvrVerifyDepth;		/* Verify Depth for certificate chains */
	short	bOurCertIsInit;	/**< 1 if our certificate is initialized and must be deinit on destruction */
	short	bOurKeyIsInit;	/**< 1 if our private key is initialized and must be deinit on destruction */
	char *pszRcvBuf;
	int lenRcvBuf;
	/**< -1: empty, 0: connection closed, 1..NSD_OSSL_MAX_RCVBUF-1: data of that size present */
	int ptrRcvBuf;		/**< offset for next recv operation if 0 < lenRcvBuf < NSD_OSSL_MAX_RCVBUF */

	/* Open SSL objects */
//	BIO *acc;		/* OpenSSL main BIO obj */
	int bAnonInit; // TODO: do we really need this? rger, 2021-07-07
	int ctx_is_copy;
	SSL_CTX *ctx;		/* credentials, ciphers, ... */
	SSL *ssl;		/* OpenSSL main SSL obj */
	osslSslState_t sslState;/**< what must we retry? */
};

/* interface is defined in nsd.h, we just implement it! */
#define nsd_osslCURR_IF_VERSION nsdCURR_IF_VERSION

/* prototypes */
PROTOTYPEObj(nsd_ossl);

/* some prototypes for things used by our nsdsel_ossl helper class */
uchar *osslStrerror(int error);
rsRetVal osslChkPeerAuth(nsd_ossl_t *pThis);
rsRetVal osslRecordRecv(nsd_ossl_t *pThis);
rsRetVal osslHandshakeCheck(nsd_ossl_t *pNsd);

/* some more prototypes to avoid warnings ... */
void osslLastSSLErrorMsg(int ret, SSL *ssl, int severity, const char* pszCallSource);
int verify_callback(int status, X509_STORE_CTX *store);
rsRetVal osslPostHandshakeCheck(nsd_ossl_t *pNsd);

int opensslh_THREAD_setup(void);
int opensslh_THREAD_cleanup(void);

/*-----------------------------------------------------------------------------*/
#define MUTEX_TYPE       pthread_mutex_t
#define MUTEX_SETUP(x)   pthread_mutex_init(&(x), NULL)
#define MUTEX_CLEANUP(x) pthread_mutex_destroy(&(x))
#define MUTEX_LOCK(x)    pthread_mutex_lock(&(x))
#define MUTEX_UNLOCK(x)  pthread_mutex_unlock(&(x))
#define THREAD_ID        pthread_self()

/* This array will store all of the mutexes available to OpenSSL. */
struct CRYPTO_dynlock_value
{
	MUTEX_TYPE mutex;
};

void dyn_destroy_function(struct CRYPTO_dynlock_value *l,
	__attribute__((unused)) const char *file, __attribute__((unused)) int line);
void dyn_lock_function(int mode, struct CRYPTO_dynlock_value *l,
	__attribute__((unused)) const char *file, __attribute__((unused)) int line);
struct CRYPTO_dynlock_value * dyn_create_function(
	__attribute__((unused)) const char *file, __attribute__((unused)) int line);
unsigned long id_function(void);
void locking_function(int mode, int n,
	__attribute__((unused)) const char * file, __attribute__((unused)) int line);
/*-----------------------------------------------------------------------------*/

/* the name of our library binary */
#define LM_NSD_OSSL_FILENAME "lmnsd_ossl"

#endif /* #ifndef INCLUDED_NSD_OSSL_H */
