ecostestdownloadfilter.cpp

基于ecos的redboot

            switch (buf[i] & 0xff)
            {
            case '$':
            case '#':
            case 0x7d:
                /* These must be escaped */
                escaped++;
                *p++ = 0x7d;
                *p++ = (unsigned char) ((buf[i] & 0xff) ^ 0x20);
                break;
            default:
                *p++ = (unsigned char) (buf[i] & 0xff);
                break;
            }
        }

        if (i < todo)
        {
            /* Escape chars have filled up the buffer prematurely, 
               and we have actually sent fewer bytes than planned.
               Fix-up the length field of the packet.  */
        
            /* FIXME: will fail if new len is a shorter string than 
               old len.  */
            
            plen += hexnumstr (plen, i);
            *plen++ = ':';
        }

        // Calculate checksum
        p2 = (unsigned char*)buf2.Data();
        p2++; // skip $
        csum = 0;
        while (p2 < p)
            csum = (unsigned char)(csum + *p2++);
        *p++ = '#';
        *p++ = (unsigned char) tohex ((csum >> 4) & 0xf);
        *p++ = (unsigned char) tohex (csum & 0xf);

        /* Send it over and over until we get a positive ack.  */

        int resend = 1;
        const unsigned char* write_ptr = (const unsigned char*) buf2.Data();
        int write_len = (int)p-(int)buf2.Data();
        while (resend)
        {
            unsigned int __written;

            Trace("Sending bytes for %p-%p\n", dl_address, dl_address+i);
            TargetWrite(serial, write_ptr, write_len);

            /* read until either a timeout occurs (-2) or '+' is read */
            for(;;)
            {
                unsigned int __read;
                serial.Read(&ch, 1, __read);
                
                if (0 == __read) {
                    tcount ++;
                    if (tcount > 3) {
                        Trace("Timeout in putpkt_binary\n");
                        return 0;
                    }
                    break;		/* Retransmit buffer */
                }
                
                switch (ch)
                {
                case '+':
                    // Now expect OK packet from target
                    unsigned char ok_msg[6];// $OK#9a
                    serial.Read(ok_msg, 6, __read);
                    
                    // Reply with ACK
                    serial.Write((void*)"+", 1, __written);
                    
                    // And process next packet.
                    resend = 0;
                    break;

                case '-':
                    // Bad packet CRC. Retransmit.
                    Trace ("Bad CRC\n");
                    break;
                    
                default:
                    Trace("Got junk..%02x\n", ch);
                    continue;           // keep reading
                }
                break;		/* Here to retransmit */
            }
        }

        len -= i;
        dl_address += i;
        buf += i;
    }

    return 1;
}    

bool CALLBACK
DownloadFilterFunction(void*& pBuf,
                       unsigned int& nRead,
                       CeCosSerial& serial,
                       CeCosSocket& socket,
                       void* pParem)
{
    CeCosTestDownloadFilter* p = (CeCosTestDownloadFilter*) pParem;
    bool res = false;

    try {
        res = p->FilterFunctionProper(pBuf, nRead, serial, socket);
    } 
    catch (LPCTSTR s) {
        TRACE(_T("Download filter caught string: %s\n"), s);
    }
    catch (...) {
        TRACE(_T("Download filter caught unknown exception\n"));
    }

    return res;
}

bool
CeCosTestDownloadFilter::FilterFunctionProper(void*& pBuf,
                                              unsigned int& nRead,
                                              CeCosSerial& serial,
                                              CeCosSocket& socket)
{
    char* buffer = (char*) pBuf;

    // Assume the worst - don't allow session to continue until a successful
    // download.
    m_bContinueSession = false;

    // Output the serial data if option enabled
    if (m_bOptSerDebug)
        PrintHex((unsigned char*) buffer, nRead);

    // Stop here if in NULL-filter mode
    if (m_bNullFilter)
        return true;

    // Command handling.
    // Be strict here; very first byte we see must be the start marker,
    // else go into NULL-filter mode
    unsigned int i = 0;
    if (!m_bCmdFlag) {
        if ('@' != buffer[i]) {
            m_bNullFilter = true;
            return true;
        }
        m_bCmdFlag = true;
    }

    // If reading a command, look for the end marker.
    if (m_bCmdFlag) {
        char c = 0;
        while (i < nRead && m_nCmdIndex < MAX_CMD_LEN) {
            c = buffer[i++];
            m_aCmd[m_nCmdIndex++] = c;
            if ('!' == c) {
                if (i != nRead) {
                    throw _T("Extra bytes after command packet!?!");
                }
            }
        }

        if (MAX_CMD_LEN == m_nCmdIndex) {
            Trace("Received too long command. Ignoring it!\n");
            m_nCmdIndex = 0;
            m_bCmdFlag = false;
        } else if ('!' == c) {
            // Was the command completed?
            m_aCmd[m_nCmdIndex - 1] = 0;// terminate cmd
            m_nCmdIndex = 0;
            m_bCmdFlag = false;
            // command now in m_aCmd[]

            Trace("Got command %s\n", m_aCmd);

            // After this, never interfere.
            m_bNullFilter = true;

            // Get arguments: @<length>:<dl_address>:<start_address>!
            int length, packet_size;
            unsigned long dl_addr, start_addr;
            INIT_VALUE(&m_aCmd[1]);
            SET_VALUE(int, length);
            SET_VALUE(unsigned long, dl_addr);
            SET_VALUE(unsigned long, start_addr);
            SET_VALUE(int, packet_size);

            Trace("len %d, dl %08x, start %08x, packet_size %d\n", 
                  length, dl_addr, start_addr, packet_size);

            // Reply so host will send file.
            socket.send("@", 1);

            // Read file from host
            Buffer buf(length);
            if (socket.recv(buf.Data(), length)) {
            
                // Remember old blocking state, and set serial to
                // blocking reads.
                bool __blocking = serial.GetBlockingReads();
                serial.SetBlockingReads(true);
                serial.Flush();

                // Send + to target, acking whatever packet was pending
                unsigned int __written = 0;
                serial.Write((void*)"+", 1, __written);
                
                // Convert to packets and transfer to target.
                if (put_binary((unsigned char*) buf.Data(), 
                               length, dl_addr, packet_size, serial)) {
                    // Send detach signal to target
                    unsigned char ch;
                    unsigned int __read;
                    serial.Write((void*)"$D#44", 5, __written);
                    serial.Read(&ch, 1, __read);
                    
                    // Reply to host marking end of download
                    socket.send("+", 1);

                    // Let server know it's OK to accept another connection
                    // in this session.
                    m_bContinueSession = true;
                } else {
                    // Reply to host marking failed download
                    socket.send("-", 1);
                }

                // Reset previous blocking mode
                serial.SetBlockingReads(__blocking);

            } else {
                // Reply to host marking failed file transfer
                socket.send("?", 1);
            }
        }
        nRead = 0;                      // Never leave anything for caller
                                        // This is a violation of the intended
                                        // filter function behavior.
    }
    return true;
}