int ssl3_read_bytes(SSL *s, int type, unsigned char *buf, int len, int peek)
{
    int al, i, j, ret;
    unsigned int n;
    SSL3_RECORD *rr;
    void (*cb) (const SSL *ssl, int type2, int val) = NULL;

    if (s->s3->rbuf.buf == NULL) /* Not initialized yet */
        if (!ssl3_setup_read_buffer(s))
            return (-1);

    if ((type && (type != SSL3_RT_APPLICATION_DATA)
         && (type != SSL3_RT_HANDSHAKE)) || (peek
                                             && (type !=
                                                 SSL3_RT_APPLICATION_DATA))) {
        SSLerr(SSL_F_SSL3_READ_BYTES, ERR_R_INTERNAL_ERROR);
        return -1;
    }

    if ((type == SSL3_RT_HANDSHAKE) && (s->s3->handshake_fragment_len > 0))
        /* (partially) satisfy request from storage */
    {
        unsigned char *src = s->s3->handshake_fragment;
        unsigned char *dst = buf;
        unsigned int k;

        /* peek == 0 */
        n = 0;
        while ((len > 0) && (s->s3->handshake_fragment_len > 0)) {
            *dst++ = *src++;
            len--;
            s->s3->handshake_fragment_len--;
            n++;
        }
        /* move any remaining fragment bytes: */
        for (k = 0; k < s->s3->handshake_fragment_len; k++)
            s->s3->handshake_fragment[k] = *src++;
        return n;
    }

    /*
     * Now s->s3->handshake_fragment_len == 0 if type == SSL3_RT_HANDSHAKE.
     */

    if (!s->in_handshake && SSL_in_init(s)) {
        /* type == SSL3_RT_APPLICATION_DATA */
        i = s->handshake_func(s);
        if (i < 0)
            return (i);
        if (i == 0) {
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_SSL_HANDSHAKE_FAILURE);
            return (-1);
        }
    }
 start:
    s->rwstate = SSL_NOTHING;

    /*-
     * s->s3->rrec.type         - is the type of record
     * s->s3->rrec.data,    - data
     * s->s3->rrec.off,     - offset into 'data' for next read
     * s->s3->rrec.length,  - number of bytes.
     */
    rr = &(s->s3->rrec);

    /* get new packet if necessary */
    if ((rr->length == 0) || (s->rstate == SSL_ST_READ_BODY)) {
        ret = ssl3_get_record(s);
        if (ret <= 0)
            return (ret);
    }

    /*
     * Reset the count of consecutive warning alerts if we've got a non-empty
     * record that isn't an alert.
     */
    if (rr->type != SSL3_RT_ALERT && rr->length != 0)
        s->cert->alert_count = 0;

    /* we now have a packet which can be read and processed */

    if (s->s3->change_cipher_spec /* set when we receive ChangeCipherSpec,
                                   * reset by ssl3_get_finished */
        && (rr->type != SSL3_RT_HANDSHAKE)) {
        al = SSL_AD_UNEXPECTED_MESSAGE;
        SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_DATA_BETWEEN_CCS_AND_FINISHED);
        goto f_err;
    }

    /*
     * If the other end has shut down, throw anything we read away (even in
     * 'peek' mode)
     */
    if (s->shutdown & SSL_RECEIVED_SHUTDOWN) {
        rr->length = 0;
        s->rwstate = SSL_NOTHING;
        return (0);
    }

    if (type == rr->type) {     /* SSL3_RT_APPLICATION_DATA or
                                 * SSL3_RT_HANDSHAKE */
        /*
         * make sure that we are not getting application data when we are
         * doing a handshake for the first time
         */
        if (SSL_in_init(s) && (type == SSL3_RT_APPLICATION_DATA) &&
            (s->enc_read_ctx == NULL)) {
            al = SSL_AD_UNEXPECTED_MESSAGE;
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_APP_DATA_IN_HANDSHAKE);
            goto f_err;
        }

        if (len <= 0)
            return (len);

        if ((unsigned int)len > rr->length)
            n = rr->length;
        else
            n = (unsigned int)len;

        memcpy(buf, &(rr->data[rr->off]), n);
        if (!peek) {
            rr->length -= n;
            rr->off += n;
            if (rr->length == 0) {
                s->rstate = SSL_ST_READ_HEADER;
                rr->off = 0;
                if (s->mode & SSL_MODE_RELEASE_BUFFERS
                    && s->s3->rbuf.left == 0)
                    ssl3_release_read_buffer(s);
            }
        }
        return (n);
    }

    /*
     * If we get here, then type != rr->type; if we have a handshake message,
     * then it was unexpected (Hello Request or Client Hello).
     */

    /*
     * In case of record types for which we have 'fragment' storage, fill
     * that so that we can process the data at a fixed place.
     */
    {
        unsigned int dest_maxlen = 0;
        unsigned char *dest = NULL;
        unsigned int *dest_len = NULL;

        if (rr->type == SSL3_RT_HANDSHAKE) {
            dest_maxlen = sizeof(s->s3->handshake_fragment);
            dest = s->s3->handshake_fragment;
            dest_len = &s->s3->handshake_fragment_len;
        } else if (rr->type == SSL3_RT_ALERT) {
            dest_maxlen = sizeof(s->s3->alert_fragment);
            dest = s->s3->alert_fragment;
            dest_len = &s->s3->alert_fragment_len;
        }
#ifndef OPENSSL_NO_HEARTBEATS
        else if (rr->type == TLS1_RT_HEARTBEAT) {
            i = tls1_process_heartbeat(s);

            if (i < 0)
                return i;

            rr->length = 0;
            if (s->mode & SSL_MODE_AUTO_RETRY)
                goto start;

            /* Exit and notify application to read again */
            s->rwstate = SSL_READING;
            BIO_clear_retry_flags(SSL_get_rbio(s));
            BIO_set_retry_read(SSL_get_rbio(s));
            return (-1);
        }
#endif

        if (dest_maxlen > 0) {
            n = dest_maxlen - *dest_len; /* available space in 'dest' */
            if (rr->length < n)
                n = rr->length; /* available bytes */

            /* now move 'n' bytes: */
            while (n-- > 0) {
                dest[(*dest_len)++] = rr->data[rr->off++];
                rr->length--;
            }

            if (*dest_len < dest_maxlen)
                goto start;     /* fragment was too small */
        }
    }

    /*-
     * s->s3->handshake_fragment_len == 4  iff  rr->type == SSL3_RT_HANDSHAKE;
     * s->s3->alert_fragment_len == 2      iff  rr->type == SSL3_RT_ALERT.
     * (Possibly rr is 'empty' now, i.e. rr->length may be 0.)
     */

    /* If we are a client, check for an incoming 'Hello Request': */
    if ((!s->server) &&
        (s->s3->handshake_fragment_len >= 4) &&
        (s->s3->handshake_fragment[0] == SSL3_MT_HELLO_REQUEST) &&
        (s->session != NULL) && (s->session->cipher != NULL)) {
        s->s3->handshake_fragment_len = 0;

        if ((s->s3->handshake_fragment[1] != 0) ||
            (s->s3->handshake_fragment[2] != 0) ||
            (s->s3->handshake_fragment[3] != 0)) {
            al = SSL_AD_DECODE_ERROR;
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_BAD_HELLO_REQUEST);
            goto f_err;
        }

        if (s->msg_callback)
            s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
                            s->s3->handshake_fragment, 4, s,
                            s->msg_callback_arg);

        if (SSL_is_init_finished(s) &&
            !(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) &&
            !s->s3->renegotiate) {
            ssl3_renegotiate(s);
            if (ssl3_renegotiate_check(s)) {
                i = s->handshake_func(s);
                if (i < 0)
                    return (i);
                if (i == 0) {
                    SSLerr(SSL_F_SSL3_READ_BYTES,
                           SSL_R_SSL_HANDSHAKE_FAILURE);
                    return (-1);
                }

                if (!(s->mode & SSL_MODE_AUTO_RETRY)) {
                    if (s->s3->rbuf.left == 0) { /* no read-ahead left? */
                        BIO *bio;
                        /*
                         * In the case where we try to read application data,
                         * but we trigger an SSL handshake, we return -1 with
                         * the retry option set.  Otherwise renegotiation may
                         * cause nasty problems in the blocking world
                         */
                        s->rwstate = SSL_READING;
                        bio = SSL_get_rbio(s);
                        BIO_clear_retry_flags(bio);
                        BIO_set_retry_read(bio);
                        return (-1);
                    }
                }
            }
        }
        /*
         * we either finished a handshake or ignored the request, now try
         * again to obtain the (application) data we were asked for
         */
        goto start;
    }

    /*
     * If we are a server and get a client hello when renegotiation isn't
     * allowed send back a no renegotiation alert and carry on.
     */
    if (s->server
            && SSL_is_init_finished(s)
            && !s->s3->send_connection_binding
            && s->version > SSL3_VERSION
            && s->s3->handshake_fragment_len >= SSL3_HM_HEADER_LENGTH
            && s->s3->handshake_fragment[0] == SSL3_MT_CLIENT_HELLO
            && s->s3->previous_client_finished_len != 0
            && (s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION) == 0) {
        s->s3->handshake_fragment_len = 0;
        rr->length = 0;
        ssl3_send_alert(s, SSL3_AL_WARNING, SSL_AD_NO_RENEGOTIATION);
        goto start;
    }

    if (s->s3->alert_fragment_len >= 2) {
        int alert_level = s->s3->alert_fragment[0];
        int alert_descr = s->s3->alert_fragment[1];

        s->s3->alert_fragment_len = 0;

        if (s->msg_callback)
            s->msg_callback(0, s->version, SSL3_RT_ALERT,
                            s->s3->alert_fragment, 2, s, s->msg_callback_arg);

        if (s->info_callback != NULL)
            cb = s->info_callback;
        else if (s->ctx->info_callback != NULL)
            cb = s->ctx->info_callback;

        if (cb != NULL) {
            j = (alert_level << 8) | alert_descr;
            cb(s, SSL_CB_READ_ALERT, j);
        }

        if (alert_level == SSL3_AL_WARNING) {
            s->s3->warn_alert = alert_descr;

            s->cert->alert_count++;
            if (s->cert->alert_count == MAX_WARN_ALERT_COUNT) {
                al = SSL_AD_UNEXPECTED_MESSAGE;
                SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_TOO_MANY_WARN_ALERTS);
                goto f_err;
            }

            if (alert_descr == SSL_AD_CLOSE_NOTIFY) {
                s->shutdown |= SSL_RECEIVED_SHUTDOWN;
                return (0);
            }
            /*
             * This is a warning but we receive it if we requested
             * renegotiation and the peer denied it. Terminate with a fatal
             * alert because if application tried to renegotiatie it
             * presumably had a good reason and expects it to succeed. In
             * future we might have a renegotiation where we don't care if
             * the peer refused it where we carry on.
             */
            else if (alert_descr == SSL_AD_NO_RENEGOTIATION) {
                al = SSL_AD_HANDSHAKE_FAILURE;
                SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_NO_RENEGOTIATION);
                goto f_err;
            }
#ifdef SSL_AD_MISSING_SRP_USERNAME
            else if (alert_descr == SSL_AD_MISSING_SRP_USERNAME)
                return (0);
#endif
        } else if (alert_level == SSL3_AL_FATAL) {
            char tmp[16];

            s->rwstate = SSL_NOTHING;
            s->s3->fatal_alert = alert_descr;
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_AD_REASON_OFFSET + alert_descr);
            BIO_snprintf(tmp, sizeof(tmp), "%d", alert_descr);
            ERR_add_error_data(2, "SSL alert number ", tmp);
            s->shutdown |= SSL_RECEIVED_SHUTDOWN;
            SSL_CTX_remove_session(s->session_ctx, s->session);
            return (0);
        } else {
            al = SSL_AD_ILLEGAL_PARAMETER;
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_UNKNOWN_ALERT_TYPE);
            goto f_err;
        }

        goto start;
    }

    if (s->shutdown & SSL_SENT_SHUTDOWN) { /* but we have not received a
                                            * shutdown */
        s->rwstate = SSL_NOTHING;
        rr->length = 0;
        return (0);
    }

    if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC) {
        /*
         * 'Change Cipher Spec' is just a single byte, so we know exactly
         * what the record payload has to look like
         */
        if ((rr->length != 1) || (rr->off != 0) ||
            (rr->data[0] != SSL3_MT_CCS)) {
            al = SSL_AD_ILLEGAL_PARAMETER;
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_BAD_CHANGE_CIPHER_SPEC);
            goto f_err;
        }

        /* Check we have a cipher to change to */
        if (s->s3->tmp.new_cipher == NULL) {
            al = SSL_AD_UNEXPECTED_MESSAGE;
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_CCS_RECEIVED_EARLY);
            goto f_err;
        }

        if (!(s->s3->flags & SSL3_FLAGS_CCS_OK)) {
            al = SSL_AD_UNEXPECTED_MESSAGE;
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_CCS_RECEIVED_EARLY);
            goto f_err;
        }

        s->s3->flags &= ~SSL3_FLAGS_CCS_OK;

        rr->length = 0;

        if (s->msg_callback)
            s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC,
                            rr->data, 1, s, s->msg_callback_arg);

        s->s3->change_cipher_spec = 1;
        if (!ssl3_do_change_cipher_spec(s))
            goto err;
        else
            goto start;
    }

    /*
     * Unexpected handshake message (Client Hello, or protocol violation)
     */
    if ((s->s3->handshake_fragment_len >= 4) && !s->in_handshake) {
        if (((s->state & SSL_ST_MASK) == SSL_ST_OK) &&
            !(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS)) {
#if 0                           /* worked only because C operator preferences
                                 * are not as expected (and because this is
                                 * not really needed for clients except for
                                 * detecting protocol violations): */
            s->state = SSL_ST_BEFORE | (s->server)
                ? SSL_ST_ACCEPT : SSL_ST_CONNECT;
#else
            s->state = s->server ? SSL_ST_ACCEPT : SSL_ST_CONNECT;
#endif
            s->renegotiate = 1;
            s->new_session = 1;
        }
        i = s->handshake_func(s);
        if (i < 0)
            return (i);
        if (i == 0) {
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_SSL_HANDSHAKE_FAILURE);
            return (-1);
        }

        if (!(s->mode & SSL_MODE_AUTO_RETRY)) {
            if (s->s3->rbuf.left == 0) { /* no read-ahead left? */
                BIO *bio;
                /*
                 * In the case where we try to read application data, but we
                 * trigger an SSL handshake, we return -1 with the retry
                 * option set.  Otherwise renegotiation may cause nasty
                 * problems in the blocking world
                 */
                s->rwstate = SSL_READING;
                bio = SSL_get_rbio(s);
                BIO_clear_retry_flags(bio);
                BIO_set_retry_read(bio);
                return (-1);
            }
        }
        goto start;
    }

    switch (rr->type) {
    default:
        /*
         * TLS 1.0 and 1.1 say you SHOULD ignore unrecognised record types, but
         * TLS 1.2 says you MUST send an unexpected message alert. We use the
         * TLS 1.2 behaviour for all protocol versions to prevent issues where
         * no progress is being made and the peer continually sends unrecognised
         * record types, using up resources processing them.
         */
        al = SSL_AD_UNEXPECTED_MESSAGE;
        SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_UNEXPECTED_RECORD);
        goto f_err;
    case SSL3_RT_CHANGE_CIPHER_SPEC:
    case SSL3_RT_ALERT:
    case SSL3_RT_HANDSHAKE:
        /*
         * we already handled all of these, with the possible exception of
         * SSL3_RT_HANDSHAKE when s->in_handshake is set, but that should not
         * happen when type != rr->type
         */
        al = SSL_AD_UNEXPECTED_MESSAGE;
        SSLerr(SSL_F_SSL3_READ_BYTES, ERR_R_INTERNAL_ERROR);
        goto f_err;
    case SSL3_RT_APPLICATION_DATA:
        /*
         * At this point, we were expecting handshake data, but have
         * application data.  If the library was running inside ssl3_read()
         * (i.e. in_read_app_data is set) and it makes sense to read
         * application data at this point (session renegotiation not yet
         * started), we will indulge it.
         */
        if (s->s3->in_read_app_data &&
            (s->s3->total_renegotiations != 0) &&
            (((s->state & SSL_ST_CONNECT) &&
              (s->state >= SSL3_ST_CW_CLNT_HELLO_A) &&
              (s->state <= SSL3_ST_CR_SRVR_HELLO_A)
             ) || ((s->state & SSL_ST_ACCEPT) &&
                   (s->state <= SSL3_ST_SW_HELLO_REQ_A) &&
                   (s->state >= SSL3_ST_SR_CLNT_HELLO_A)
             )
            )) {
            s->s3->in_read_app_data = 2;
            return (-1);
        } else {
            al = SSL_AD_UNEXPECTED_MESSAGE;
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_UNEXPECTED_RECORD);
            goto f_err;
        }
    }
    /* not reached */

 f_err:
    ssl3_send_alert(s, SSL3_AL_FATAL, al);
 err:
    return (-1);
}