int tls_construct_finished(SSL *s, const char *sender, int slen)
{
    unsigned char *p;
    int i;
    unsigned long l;

    p = ssl_handshake_start(s);

    i = s->method->ssl3_enc->final_finish_mac(s,
                                              sender, slen,
                                              s->s3->tmp.finish_md);
    if (i <= 0)
        return 0;
    s->s3->tmp.finish_md_len = i;
    memcpy(p, s->s3->tmp.finish_md, i);
    l = i;

    /*
     * Copy the finished so we can use it for renegotiation checks
     */
    if (s->type == SSL_ST_CONNECT) {
        OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
        memcpy(s->s3->previous_client_finished, s->s3->tmp.finish_md, i);
        s->s3->previous_client_finished_len = i;
    } else {
        OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
        memcpy(s->s3->previous_server_finished, s->s3->tmp.finish_md, i);
        s->s3->previous_server_finished_len = i;
    }

    if (!ssl_set_handshake_header(s, SSL3_MT_FINISHED, l)) {
        SSLerr(SSL_F_TLS_CONSTRUCT_FINISHED, ERR_R_INTERNAL_ERROR);
        return 0;
    }

    return 1;
}