/* ssl.cpp                                
 *
 * Copyright (C) 2003 Sawtooth Consulting Ltd.
 *
 * This file is part of yaSSL.
 *
 * yaSSL is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * yaSSL is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */

/*  SSL source implements all openssl compatibility API functions
 *
 *  TODO: notes are mostly api additions to allow compilation with mysql
 *  they don't affect normal modes but should be provided for completeness

 *  stunnel functions at end of file
 */




/*  see man pages for function descriptions */

#include "runtime.hpp"
#include "openssl/ssl.h"
#include "handshake.hpp"
#include "yassl_int.hpp"
#include "md5.hpp"              // for TaoCrypt MD5 size assert
#include <stdio.h>

#ifdef _WIN32
    #include <windows.h>    // FindFirstFile etc..
#else
    #include <sys/types.h>  // file helper
    #include <sys/stat.h>   // stat
    #include <dirent.h>     // opendir
#endif


namespace yaSSL {

using mySTL::min;


int read_file(SSL_CTX* ctx, const char* file, int format, CertType type)
{
    if (format != SSL_FILETYPE_ASN1 && format != SSL_FILETYPE_PEM)
        return SSL_BAD_FILETYPE;

    FILE* input = fopen(file, "rb");
    if (!input)
        return SSL_BAD_FILE;

    if (type == CA) {
        x509* ptr = PemToDer(file, Cert);
        if (!ptr) {
            fclose(input);
            return SSL_BAD_FILE;
        }
        ctx->AddCA(ptr);  // takes ownership
    }
    else {
        x509*& x = (type == Cert) ? ctx->certificate_ : ctx->privateKey_;

        if (format == SSL_FILETYPE_ASN1) {
            fseek(input, 0, SEEK_END);
            long sz = ftell(input);
            rewind(input);
            x = NEW_YS x509(sz); // takes ownership
            size_t bytes = fread(x->use_buffer(), sz, 1, input);
            if (bytes != 1) {
                fclose(input);
                return SSL_BAD_FILE;
            }
        }
        else {
            x = PemToDer(file, type);
            if (!x) {
                fclose(input);
                return SSL_BAD_FILE;
            }
        }
    }
    fclose(input);
    return SSL_SUCCESS;
}


extern "C" {


SSL_METHOD* SSLv3_method()
{
    return SSLv3_client_method();
}


SSL_METHOD* SSLv3_server_method()
{
    return NEW_YS SSL_METHOD(server_end, ProtocolVersion(3,0));
}


SSL_METHOD* SSLv3_client_method()
{
    return NEW_YS SSL_METHOD(client_end, ProtocolVersion(3,0));
}


SSL_METHOD* TLSv1_server_method()
{
    return NEW_YS SSL_METHOD(server_end, ProtocolVersion(3,1));
}


SSL_METHOD* TLSv1_client_method()
{
    return NEW_YS SSL_METHOD(client_end, ProtocolVersion(3,1));
}


SSL_METHOD* SSLv23_server_method()
{
    // compatibility only, no version 2 support
    return SSLv3_server_method();
}


SSL_CTX* SSL_CTX_new(SSL_METHOD* method)
{
    return NEW_YS SSL_CTX(method);
}


void SSL_CTX_free(SSL_CTX* ctx)
{
    ysDelete(ctx);
}


SSL* SSL_new(SSL_CTX* ctx)
{
    return NEW_YS SSL(ctx);
}


void SSL_free(SSL* ssl)
{
    ysDelete(ssl);
}


int SSL_set_fd(SSL* ssl, int fd)
{
    ssl->useSocket().set_fd(fd);
    return SSL_SUCCESS;
}


int SSL_connect(SSL* ssl)
{
    sendClientHello(*ssl);
    ClientState neededState = ssl->getSecurity().get_resuming() ?
        serverFinishedComplete : serverHelloDoneComplete;
    while (ssl->getStates().getClient() < neededState) {
        if (ssl->GetError()) break;
    processReply(*ssl);
    }

    if(ssl->getCrypto().get_certManager().sendVerify())
        sendCertificate(*ssl);

    if (!ssl->getSecurity().get_resuming())
        sendClientKeyExchange(*ssl);

    if(ssl->getCrypto().get_certManager().sendVerify())
        sendCertificateVerify(*ssl);

    sendChangeCipher(*ssl);
    sendFinished(*ssl, client_end);
    ssl->flushBuffer();
    if (!ssl->getSecurity().get_resuming())
        while (ssl->getStates().getClient() < serverFinishedComplete) {
            if (ssl->GetError()) break;
        processReply(*ssl);
        }

    ssl->verifyState(serverFinishedComplete);
    ssl->useLog().ShowTCP(ssl->getSocket().get_fd());

    if (ssl->GetError())
        return SSL_FATAL_ERROR;
    return SSL_SUCCESS;
}


int SSL_write(SSL* ssl, const void* buffer, int sz)
{
    return sendData(*ssl, buffer, sz);
}


int SSL_read(SSL* ssl, void* buffer, int sz)
{
    Data data(min(sz, MAX_RECORD_SIZE), static_cast<opaque*>(buffer));
    return receiveData(*ssl, data);
}


int SSL_accept(SSL* ssl)
{
    processReply(*ssl);
    sendServerHello(*ssl);

    if (!ssl->getSecurity().get_resuming()) {
        sendCertificate(*ssl);

        if (ssl->getSecurity().get_connection().send_server_key_)
            sendServerKeyExchange(*ssl);

        if(ssl->getCrypto().get_certManager().verifyPeer())
            sendCertificateRequest(*ssl);

        sendServerHelloDone(*ssl);
        ssl->flushBuffer();

        while (ssl->getStates().getServer() < clientFinishedComplete) {
            if (ssl->GetError()) break;
            processReply(*ssl);
        }
    }
    sendChangeCipher(*ssl);
    sendFinished(*ssl, server_end);
    ssl->flushBuffer();
    if (ssl->getSecurity().get_resuming()) {
        while (ssl->getStates().getServer() < clientFinishedComplete) {
          if (ssl->GetError()) break;
          processReply(*ssl);
      }
    }

    ssl->useLog().ShowTCP(ssl->getSocket().get_fd());

    if (ssl->GetError())
        return SSL_FATAL_ERROR;
    return SSL_SUCCESS;
}


int SSL_do_handshake(SSL* ssl)
{
    if (ssl->getSecurity().get_parms().entity_ == client_end)
        return SSL_connect(ssl);
    else
        return SSL_accept(ssl);
}


int SSL_clear(SSL* ssl)
{
    ssl->useSocket().closeSocket();
    return SSL_SUCCESS;
}


int SSL_shutdown(SSL* ssl)
{
    Alert alert(warning, close_notify);
    sendAlert(*ssl, alert);
    ssl->useLog().ShowTCP(ssl->getSocket().get_fd(), true);
    ssl->useSocket().closeSocket();

    return SSL_SUCCESS;
}


SSL_SESSION* SSL_get_session(SSL* ssl)
{
    return GetSessions().lookup(
        ssl->getSecurity().get_connection().sessionID_);
}


int SSL_set_session(SSL* ssl, SSL_SESSION* session)
{
    ssl->set_session(session);
    return SSL_SUCCESS;
}


int SSL_session_reused(SSL* ssl)
{
    return ssl->getSecurity().get_resuming();
}


long SSL_SESSION_set_timeout(SSL_SESSION* sess, long t)
{
    if (!sess)
        return SSL_ERROR_NONE;

    sess->SetTimeOut(t);
    return SSL_SUCCESS;
}


long SSL_get_default_timeout(SSL* /*ssl*/)
{
    return DEFAULT_TIMEOUT;
}


const char* SSL_get_cipher_name(SSL* ssl)
{ 
    return SSL_get_cipher(ssl); 
}


const char* SSL_get_cipher(SSL* ssl)
{
    return ssl->getSecurity().get_parms().cipher_name_;
}


// SSLv2 only, not implemented
char* SSL_get_shared_ciphers(SSL* /*ssl*/, char* buf, int len)
{
    return strncpy(buf, "Not Implemented, SSLv2 only", len);
}


const char* SSL_get_cipher_list(SSL* ssl, int priority)
{
    if (priority < 0 || priority >= MAX_CIPHERS)
        return 0;

    if (ssl->getSecurity().get_parms().cipher_list_[priority][0])
        return ssl->getSecurity().get_parms().cipher_list_[priority];

    return 0;
}


int SSL_CTX_set_cipher_list(SSL_CTX* ctx, const char* list)
{
    if (ctx->SetCipherList(list))
        return SSL_SUCCESS;
    else
        return SSL_FAILURE;
}


const char* SSL_get_version(SSL* ssl)
{
    static const char* version3 =  "SSLv3";
    static const char* version31 = "TLSv1";

    return ssl->isTLS() ? version31 : version3;
}

const char* SSLeay_version(int)
{
    static const char* version = "SSLeay yaSSL compatibility";
    return version;
}


int SSL_get_error(SSL* ssl, int /*previous*/)
{
    return ssl->getStates().What();
}


X509* SSL_get_peer_certificate(SSL* ssl)
{
    return ssl->getCrypto().get_certManager().get_peerX509();
}


void X509_free(X509* /*x*/)
{
    // peer cert set for deletion during destruction
    // no need to delete now
}


X509* X509_STORE_CTX_get_current_cert(X509_STORE_CTX* ctx)
{
    return ctx->current_cert;
}


int X509_STORE_CTX_get_error(X509_STORE_CTX* ctx)
{
    return ctx->error;
}


int X509_STORE_CTX_get_error_depth(X509_STORE_CTX* ctx)
{
    return ctx->error_depth;
}


// copy name into buffer, at most sz bytes, if buffer is null
// will malloc buffer, caller responsible for freeing
char* X509_NAME_oneline(X509_NAME* name, char* buffer, int sz)
{
    if (!name->GetName()) return buffer;

    int len    = strlen(name->GetName()) + 1;
    int copySz = min(len, sz);

    if (!buffer) {
        buffer = (char*)malloc(len);
        if (!buffer) return buffer;
        copySz = len;
    }

    if (copySz == 0)
        return buffer;

    memcpy(buffer, name->GetName(), copySz - 1);
    buffer[copySz - 1] = 0;

    return buffer;
}


X509_NAME* X509_get_issuer_name(X509* x)
{
    return  x->GetIssuer();
}


X509_NAME* X509_get_subject_name(X509* x)
{
    return x->GetSubject();
}


void SSL_load_error_strings()   // compatibility only 
{}


void SSL_set_connect_state(SSL*)
{
    // already a client by default
}


void SSL_set_accept_state(SSL* ssl)
{
    ssl->useSecurity().use_parms().entity_ = server_end;
}


long SSL_get_verify_result(SSL*)
{
    // won't get here if not OK
    return X509_V_OK;
}


long SSL_CTX_sess_set_cache_size(SSL_CTX* /*ctx*/, long /*sz*/)
{
    // unlimited size, can't set for now
    return 0;
}


long SSL_CTX_get_session_cache_mode(SSL_CTX*)
{
    // always 0, unlimited size for now
    return 0;
}


long SSL_CTX_set_tmp_dh(SSL_CTX* ctx, DH* dh)
{
    if (ctx->SetDH(*dh))
        return SSL_SUCCESS;
    else
        return SSL_FAILURE;
}


int SSL_CTX_use_certificate_file(SSL_CTX* ctx, const char* file, int format)
{
    return read_file(ctx, file, format, Cert);
}


int SSL_CTX_use_PrivateKey_file(SSL_CTX* ctx, const char* file, int format)
{
    return read_file(ctx, file, format, PrivateKey);
}


void SSL_CTX_set_verify(SSL_CTX* ctx, int mode, VerifyCallback /*vc*/)
{
    if (mode & SSL_VERIFY_PEER)
        ctx->setVerifyPeer();

    if (mode == SSL_VERIFY_NONE)
        ctx->setVerifyNone();

    if (mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)
        ctx->setFailNoCert();
}


int SSL_CTX_load_verify_locations(SSL_CTX* ctx, const char* file,
                                  const char* path)
{
    int       ret = SSL_SUCCESS;
    const int HALF_PATH = 128;

    if (file) ret = read_file(ctx, file, SSL_FILETYPE_PEM, CA);

    if (ret == SSL_SUCCESS && path) {
        // call read_file for each reqular file in path
#ifdef _WIN32

        WIN32_FIND_DATA FindFileData;
        HANDLE hFind;

        char name[MAX_PATH + 1];  // directory specification
        strncpy(name, path, MAX_PATH - 3);
        strncat(name, "\\*", 3);

        hFind = FindFirstFile(name, &FindFileData);
        if (hFind == INVALID_HANDLE_VALUE) return SSL_BAD_PATH;

        do {
            if (FindFileData.dwFileAttributes != FILE_ATTRIBUTE_DIRECTORY) {
                strncpy(name, path, MAX_PATH - 2 - HALF_PATH);
                strncat(name, "\\", 2);
                strncat(name, FindFileData.cFileName, HALF_PATH);
                ret = read_file(ctx, name, SSL_FILETYPE_PEM, CA);
            }
        } while (ret == SSL_SUCCESS && FindNextFile(hFind, &FindFileData));

        FindClose(hFind);

#else   // _WIN32

        const int MAX_PATH = 260;

        DIR* dir = opendir(path);
        if (!dir) return SSL_BAD_PATH;

        struct dirent* entry;
        struct stat    buf;
        char           name[MAX_PATH + 1];

        while (ret == SSL_SUCCESS && (entry = readdir(dir))) {
            strncpy(name, path, MAX_PATH - 1 - HALF_PATH);
            strncat(name, "/", 1);
            strncat(name, entry->d_name, HALF_PATH);
            if (stat(name, &buf) < 0) return SSL_BAD_STAT;
     
            if (S_ISREG(buf.st_mode))
                ret = read_file(ctx, name, SSL_FILETYPE_PEM, CA);
        }

        closedir(dir);

#endif
    }

    return ret;
}


int SSL_CTX_set_default_verify_paths(SSL_CTX* /*ctx*/)
{
    // TODO: figure out way to set/store default path, then call load_verify
    return SSL_NOT_IMPLEMENTED;
}


int SSL_CTX_set_session_id_context(SSL_CTX*, const unsigned char*,
                                    unsigned int)
{
    // No application specific context needed for yaSSL
    return SSL_SUCCESS;
}


int SSL_CTX_check_private_key(SSL_CTX* /*ctx*/)
{
    // TODO: check private against public for RSA match
    return SSL_NOT_IMPLEMENTED;
}


// TODO: all session stats
long SSL_CTX_sess_accept(SSL_CTX* ctx)
{
    return ctx->GetStats().accept_;
}


long SSL_CTX_sess_connect(SSL_CTX* ctx)
{
    return ctx->GetStats().connect_;
}


long SSL_CTX_sess_accept_good(SSL_CTX* ctx)
{
    return ctx->GetStats().acceptGood_;
}


long SSL_CTX_sess_connect_good(SSL_CTX* ctx)
{
    return ctx->GetStats().connectGood_;
}


long SSL_CTX_sess_accept_renegotiate(SSL_CTX* ctx)
{
    return ctx->GetStats().acceptRenegotiate_;
}


long SSL_CTX_sess_connect_renegotiate(SSL_CTX* ctx)
{
    return ctx->GetStats().connectRenegotiate_;
}


long SSL_CTX_sess_hits(SSL_CTX* ctx)
{
    return ctx->GetStats().hits_;
}


long SSL_CTX_sess_cb_hits(SSL_CTX* ctx)
{
    return ctx->GetStats().cbHits_;
}


long SSL_CTX_sess_cache_full(SSL_CTX* ctx)
{
    return ctx->GetStats().cacheFull_;
}


long SSL_CTX_sess_misses(SSL_CTX* ctx)
{
    return ctx->GetStats().misses_;
}


long SSL_CTX_sess_timeouts(SSL_CTX* ctx)
{
    return ctx->GetStats().timeouts_;
}


long SSL_CTX_sess_number(SSL_CTX* ctx)
{
    return ctx->GetStats().number_;
}


long SSL_CTX_sess_get_cache_size(SSL_CTX* ctx)
{
    return ctx->GetStats().getCacheSize_;
}
// end session stats TODO:


int SSL_CTX_get_verify_mode(SSL_CTX* ctx)
{
    return ctx->GetStats().verifyMode_;
}


int SSL_get_verify_mode(SSL* ssl)
{
    return ssl->getSecurity().GetContext()->GetStats().verifyMode_;
}


int SSL_CTX_get_verify_depth(SSL_CTX* ctx)
{
    return ctx->GetStats().verifyDepth_;
}


int SSL_get_verify_depth(SSL* ssl)
{
    return ssl->getSecurity().GetContext()->GetStats().verifyDepth_;
}


long SSL_CTX_set_options(SSL_CTX*, long)
{
    // TDOD:
    return SSL_SUCCESS;
}


void SSL_CTX_set_info_callback(SSL_CTX*, void (*)())
{
    // TDOD:
}


void OpenSSL_add_all_algorithms()  // compatibility only
{}


int SSL_library_init()  // compatiblity only
{
    return 1;
}


DH* DH_new(void)
{
    DH* dh = NEW_YS DH;
    if (dh)
        dh->p = dh->g = 0;
    return dh;
}


void DH_free(DH* dh)
{
    ysDelete(dh->g);
    ysDelete(dh->p);
    ysDelete(dh);
}


// convert positive big-endian num of length sz into retVal, which may need to 
// be created
BIGNUM* BN_bin2bn(const unsigned char* num, int sz, BIGNUM* retVal)
{
    using mySTL::auto_ptr;
    bool created = false;
    auto_ptr<BIGNUM> bn(ysDelete);

    if (!retVal) {
        created = true;
        bn.reset(NEW_YS BIGNUM);
        retVal = bn.get();
    }

    retVal->assign(num, sz);

    if (created)
        return bn.release();
    else
        return retVal;
}


unsigned long ERR_get_error_line_data(const char**, int*, const char**, int *)
{
    //return SSL_NOT_IMPLEMENTED;
    return 0;
}


void ERR_print_errors_fp(FILE* /*fp*/)
{
    // need ssl access to implement TODO:
    //fprintf(fp, "%s", ssl.get_states().errorString_.c_str());
}


char* ERR_error_string(unsigned long errNumber, char* buffer)
{
    static char* msg = "Please supply a buffer for error string";

    if (buffer) {
        SetErrorString(YasslError(errNumber), buffer);
        return buffer;
    }

    return msg;
}


const char* X509_verify_cert_error_string(long /* error */)
{
    // TODO:
    static const char* msg = "Not Implemented";
    return msg;
}


const EVP_MD* EVP_md5(void)
{
    return GetCryptProvider().NewMd5();
}


const EVP_CIPHER* EVP_des_ede3_cbc(void)
{
    return GetCryptProvider().NewDesEde();
}


int EVP_BytesToKey(const EVP_CIPHER* type, const EVP_MD* md, const byte* salt,
                   const byte* data, int sz, int count, byte* key, byte* iv)
{
    EVP_MD* myMD = const_cast<EVP_MD*>(md);
    uint digestSz = myMD->get_digestSize();
    byte digest[SHA_LEN];                   // max size

    int keyLen    = type->get_keySize();
    int ivLen     = type->get_ivSize();
    int keyLeft   = keyLen;
    int ivLeft    = ivLen;
    int keyOutput = 0;

    while (keyOutput < (keyLen + ivLen)) {
        int digestLeft = digestSz;
        // D_(i - 1)
        if (keyOutput)                      // first time D_0 is empty
            myMD->update(digest, digestSz);
        // data
        myMD->update(data, sz);
        // salt
        if (salt)
            myMD->update(salt, EVP_SALT_SZ);
        myMD->get_digest(digest);
        // count
        for (int j = 1; j < count; j++) {
            myMD->update(digest, digestSz);
            myMD->get_digest(digest);
        }

        if (keyLeft) {
            int store = min(keyLeft, static_cast<int>(digestSz));
            memcpy(&key[keyLen - keyLeft], digest, store);

            keyOutput  += store;
            keyLeft    -= store;
            digestLeft -= store;
        }

        if (ivLeft && digestLeft) {
            int store = min(ivLeft, digestLeft);
            memcpy(&iv[ivLen - ivLeft], digest, store);

            keyOutput += store;
            ivLeft    -= store;
        }
    }
    assert(keyOutput == (keyLen + ivLen));
    return keyOutput;
}



void DES_set_key_unchecked(const_DES_cblock* key, DES_key_schedule* schedule)
{
    memcpy(schedule, key, sizeof(const_DES_cblock));
}


void DES_ede3_cbc_encrypt(const byte* input, byte* output, long sz,
                          DES_key_schedule* ks1, DES_key_schedule* ks2,
                          DES_key_schedule* ks3, DES_cblock* ivec, int enc)
{
    DES_EDE des;
    byte key[DES_EDE_KEY_SZ];

    memcpy(key, *ks1, DES_BLOCK);
    memcpy(&key[DES_BLOCK], *ks2, DES_BLOCK);
    memcpy(&key[DES_BLOCK * 2], *ks3, DES_BLOCK);

    if (enc) {
        des.set_encryptKey(key, *ivec);
        des.encrypt(output, input, sz);
    }
    else {
        des.set_decryptKey(key, *ivec);
        des.decrypt(output, input, sz);
    }
}


// functions for libcurl
int RAND_status()
{
    return 1;  /* TaoCrypt provides enough seed */
}


int DES_set_key(const_DES_cblock* key, DES_key_schedule* schedule)
{
    memcpy(schedule, key, sizeof(const_DES_cblock));
    return 1;
}


void DES_set_odd_parity(DES_cblock* key)
{
    // not needed now for TaoCrypt
}


void DES_ecb_encrypt(DES_cblock* input, DES_cblock* output,
                     DES_key_schedule* key, int enc)
{
    DES  des;

    if (enc) {
        des.set_encryptKey(*key, 0);
        des.encrypt(*output, *input, DES_BLOCK);
    }
    else {
        des.set_decryptKey(*key, 0);
        des.decrypt(*output, *input, DES_BLOCK);
    }
}


void SSL_CTX_set_default_passwd_cb_userdata(SSL_CTX*, void* userdata)
{
    // yaSSL doesn't support yet, unencrypt your PEM file with userdata
    // before handing off to yaSSL
}


X509* SSL_get_certificate(SSL* ssl)
{
    // only used to pass to get_privatekey which isn't used
    return 0;
}


EVP_PKEY* SSL_get_privatekey(SSL* ssl)
{
    // only called, not used
    return 0;
}


void SSL_SESSION_free(SSL_SESSION* session)
{
    // managed by singleton
}



EVP_PKEY* X509_get_pubkey(X509* x)
{
    // called, not used though
    return 0;
}


int EVP_PKEY_copy_parameters(EVP_PKEY* to, const EVP_PKEY* from)
{
    // called, not used though
    return 0;
}


void EVP_PKEY_free(EVP_PKEY* pkey)
{
    // never allocated from above
}


void ERR_error_string_n(unsigned long e, char *buf, size_t len)
{
    if (len) ERR_error_string(e, buf);
}


void ERR_free_strings(void)
{
    // handled internally
}


void EVP_cleanup(void)
{
    // nothing to do yet
}


ASN1_TIME* X509_get_notBefore(X509* x)
{
    if (x) return x->GetBefore();
    return 0;
}


ASN1_TIME* X509_get_notAfter(X509* x)
{
    if (x) return x->GetAfter();
    return 0;
}


SSL_METHOD* SSLv23_client_method(void)  /* doesn't actually roll back */
{
    return SSLv3_client_method();
}


SSL_METHOD* SSLv2_client_method(void)   /* will never work, no v 2    */
{
    return 0;
}


SSL_SESSION* SSL_get1_session(SSL* ssl)  /* what's ref count */
{
    return SSL_get_session(ssl);
}


void GENERAL_NAMES_free(STACK_OF(GENERAL_NAME) *x)
{
    // no extension names supported yet
}


int sk_GENERAL_NAME_num(STACK_OF(GENERAL_NAME) *x)
{
    // no extension names supported yet
    return 0;
}


GENERAL_NAME* sk_GENERAL_NAME_value(STACK_OF(GENERAL_NAME) *x, int i)
{
    // no extension names supported yet
    return 0;
}


unsigned char* ASN1_STRING_data(ASN1_STRING* x)
{
    if (x) return x->data;
    return 0;
}


int ASN1_STRING_length(ASN1_STRING* x)
{
    if (x) return x->length;
    return 0;
}


int ASN1_STRING_type(ASN1_STRING *x)
{
    if (x) return x->type;
    return 0;
}


int X509_NAME_get_index_by_NID(X509_NAME* name,int nid, int lastpos)
{
    int idx = -1;  // not found
    const char* start = &name->GetName()[lastpos + 1];

    switch (nid) {
    case NID_commonName:
        const char* found = strstr(start, "/CN=");
        if (found) {
            found += 4;  // advance to str
            idx = found - start + lastpos + 1;
        }
        break;
    }

    return idx;
}


ASN1_STRING* X509_NAME_ENTRY_get_data(X509_NAME_ENTRY* ne)
{
    // the same in yaSSL
    return ne;
}


X509_NAME_ENTRY* X509_NAME_get_entry(X509_NAME* name, int loc)
{
    return name->GetEntry(loc);
}


// already formatted, caller responsible for freeing *out
int ASN1_STRING_to_UTF8(unsigned char** out, ASN1_STRING* in)
{
    if (!in) return 0;

    *out = (unsigned char*)malloc(in->length + 1);
    if (*out) {
        memcpy(*out, in->data, in->length);
        (*out)[in->length] = 0;
    }
    return in->length;
}


void* X509_get_ext_d2i(X509* x, int nid, int* crit, int* idx)
{
    // no extensions supported yet
    return 0;
}


void MD4_Init(MD4_CTX* md4)
{
    assert(0);  // not yet supported, build compat. only
}


void MD4_Update(MD4_CTX* md4, const void* data, unsigned long sz)
{
}


void MD4_Final(unsigned char* hash, MD4_CTX* md4)
{
}


void MD5_Init(MD5_CTX* md5)
{
    // make sure we have a big enough buffer
    typedef char ok[sizeof(md5->buffer) >= sizeof(TaoCrypt::MD5) ? 1 : -1];
    (void) sizeof(ok);

    // using TaoCrypt since no dynamic memory allocated
    // and no destructor will be called
    new (reinterpret_cast<yassl_pointer>(md5->buffer)) TaoCrypt::MD5();
}


void MD5_Update(MD5_CTX* md5, const void* data, unsigned long sz)
{
    reinterpret_cast<TaoCrypt::MD5*>(md5->buffer)->Update(
                static_cast<const byte*>(data), static_cast<unsigned int>(sz));
}


void MD5_Final(unsigned char* hash, MD5_CTX* md5)
{
    reinterpret_cast<TaoCrypt::MD5*>(md5->buffer)->Final(hash);
}


    // functions for stunnel

    void RAND_screen()
    {
        // TODO:
    }


    const char* RAND_file_name(char*, size_t)
    {
        // TODO:
        return 0;
    }


    int RAND_write_file(const char*)
    {
        // TODO:
        return 0;
    }


    int RAND_load_file(const char*, long)
    {
        // TODO:
        return 0;
    }


    void RSA_free(RSA*)
    {
        // TODO:
    }


    RSA* RSA_generate_key(int, unsigned long, void(*)(int, int, void*), void*)
    {
        //  TODO:
        return 0;
    }


    int X509_LOOKUP_add_dir(X509_LOOKUP*, const char*, long)
    {
        // TODO:
        return SSL_SUCCESS;
    }


    int X509_LOOKUP_load_file(X509_LOOKUP*, const char*, long)
    {
        // TODO:
        return SSL_SUCCESS;
    }


    X509_LOOKUP_METHOD* X509_LOOKUP_hash_dir(void)
    {
        // TODO:
        return 0;
    }


    X509_LOOKUP_METHOD* X509_LOOKUP_file(void)
    {
        // TODO:
        return 0;
    }


    X509_LOOKUP* X509_STORE_add_lookup(X509_STORE*, X509_LOOKUP_METHOD*)
    {
        // TODO:
        return 0;
    }


    int X509_STORE_get_by_subject(X509_STORE_CTX*, int, X509_NAME*, X509_OBJECT*)
    {
        // TODO:
        return SSL_SUCCESS;
    }


    X509_STORE* X509_STORE_new(void)
    {
        // TODO:
        return 0;
    }

    char* SSL_alert_type_string_long(int)
    {
        // TODO:
        return 0;
    }


    char* SSL_alert_desc_string_long(int)
    {
        // TODO:
        return 0;
    }


    char* SSL_state_string_long(SSL*)
    {
        // TODO:
        return 0;
    }


    void SSL_CTX_set_tmp_rsa_callback(SSL_CTX*, RSA*(*)(SSL*, int, int))
    {
        // TDOD:
    }


    long SSL_CTX_set_session_cache_mode(SSL_CTX*, long)
    {
        // TDOD:
        return SSL_SUCCESS;
    }


    long SSL_CTX_set_timeout(SSL_CTX*, long)
    {
        // TDOD:
        return SSL_SUCCESS;
    }


    int SSL_CTX_use_certificate_chain_file(SSL_CTX*, const char*)
    {
        // TDOD:
        return SSL_SUCCESS;
    }


    void SSL_CTX_set_default_passwd_cb(SSL_CTX*, pem_password_cb)
    {
        // TDOD:
    }


    int SSL_CTX_use_RSAPrivateKey_file(SSL_CTX*, const char*, int)
    {
        // TDOD:
        return SSL_SUCCESS;
    }


    int SSL_set_rfd(SSL*, int)
    {
        return SSL_SUCCESS; // TODO:
    }


    int SSL_set_wfd(SSL*, int)
    {
        return SSL_SUCCESS; // TODO:
    }


    int SSL_pending(SSL*)
    {
        return SSL_SUCCESS; // TODO:
    }


    int SSL_want_read(SSL*)
    {
        return 0; // TODO:
    }


    int SSL_want_write(SSL*)
    {
        return 0; // TODO:
    }


    void SSL_set_shutdown(SSL*, int)
    {
        // TODO:
    }


    SSL_CIPHER* SSL_get_current_cipher(SSL*)
    {
        // TODO:
        return 0;
    }


    char* SSL_CIPHER_description(SSL_CIPHER*, char*, int)
    {
        // TODO:
        return 0;
    }


    int SSLeay_add_ssl_algorithms()  // compatibility only
    {
        return 1;
    }


    void ERR_remove_state(unsigned long)
    {
        // TODO:
    }


    int ERR_GET_REASON(int l)
    {
        return l & 0xfff;
    }


    unsigned long ERR_peek_error()
    {
        return 0;  // TODO:
    }


    unsigned long ERR_get_error()
    {
        return ERR_peek_error();
    }


    // end stunnel needs


} // extern "C"
} // namespace