PLCReadParameterBlock.c
Author: cmaier@cmassoc.net

    /*====================================================================*
     *
     *   Copyright (c) 2013 Qualcomm Atheros, Inc.
     *
     *   All rights reserved.
     *
     *   Redistribution and use in source and binary forms, with or
     *   without modification, are permitted (subject to the limitations
     *   in the disclaimer below) provided that the following conditions
     *   are met:
     *
     *   * Redistributions of source code must retain the above copyright
     *     notice, this list of conditions and the following disclaimer.
     *
     *   * Redistributions in binary form must reproduce the above
     *     copyright notice, this list of conditions and the following
     *     disclaimer in the documentation and/or other materials
     *     provided with the distribution.
     *
     *   * Neither the name of Qualcomm Atheros nor the names of
     *     its contributors may be used to endorse or promote products
     *     derived from this software without specific prior written
     *     permission.
     *
     *   NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE
     *   GRANTED BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE
     *   COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
     *   IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     *   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     *   PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
     *   OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     *   NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     *   LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     *   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     *   CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
     *   OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     *   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     *
     *--------------------------------------------------------------------*/

    /*====================================================================*
     *
     *   signed PLCReadParameterBlock (struct channel * channel, struct message * message, void * memory, size_t extent);
     *
     *   plc.h
     *
     *   Read the PIB Image from an INT6000 using as many VS_RD_MOD
     *   messages as needed; Write image blocks to file as they are
     *   read;
     *
     *   the objective here is to read the PIB module in 1024 byte blocks
     *   until the module offset equals or exceeds the PIB actual; we do
     *   not know the PIB actual until we have read the header contained
     *   in the first block read from OFFSET 0;
     *
     *   MOFFSET and MLENGTH fields occupy different offsets in REQ and CNF
     *   messages; we exploit that by initializing them using CNF message
     *   offsets then copying values into REQ message offsets before each
     *   read; this works because confirmation messages always return all
     *   the data we request or nothing at all;
     *
     *   Contributor(s):
     *      Charles Maier <cmaier@qca.qualcomm.com>
     *      Nathaniel Houghton <nhoughto@qca.qualcomm.com>
     *
     *--------------------------------------------------------------------*/

    #ifndef READPARAMETERBLOCK_SOURCE
    #define READPARAMETERBLOCK_SOURCE

    #include <stdint.h>
    #include <unistd.h>
    #include <memory.h>

    #include "../tools/error.h"
    #include "../tools/files.h"
    #include "../pib/pib.h"
    #include "../plc/plc.h"

    signed PLCReadParameterBlock (struct channel * channel, struct message * message, void * memory, size_t extent)

    {
    	uint8_t * buffer = (uint8_t *)(memory);

    #ifndef __GNUC__
    #pragma pack (push,1)
    #endif

    	struct __packed vs_rd_mod_request
    	{
    		struct ethernet_hdr ethernet;
    		struct qualcomm_hdr qualcomm;
    		uint8_t MODULEID;
    		uint8_t MACCESS;
    		uint16_t MLENGTH;
    		uint32_t MOFFSET;
    		uint8_t MSECRET [16];
    	}
    	* request = (struct vs_rd_mod_request *) (message);
    	struct __packed vs_rd_mod_confirm
    	{
    		struct ethernet_hdr ethernet;
    		struct qualcomm_hdr qualcomm;
    		uint8_t MSTATUS;
    		uint8_t RESERVED1 [3];
    		uint8_t MODULEID;
    		uint8_t RESERVED;
    		uint16_t MLENGTH;
    		uint32_t MOFFSET;
    		uint32_t CHKSUM;
    		uint8_t BUFFER [PLC_RECORD_SIZE];
    	}
    	* confirm = (struct vs_rd_mod_confirm *) (message);

    #ifndef __GNUC__
    #pragma pack (pop)
    #endif

    	uint16_t length = 0;
    	uint32_t offset = 0;
    	signed actual = PLC_RECORD_SIZE;
    	do
    	{
    		memset (message, 0, sizeof (* message));
    		EthernetHeader (&request->ethernet, channel->peer, channel->host, channel->type);
    		QualcommHeader (&request->qualcomm, 0, (VS_RD_MOD | MMTYPE_REQ));
    		request->MODULEID = VS_MODULE_PIB;
    		request->MLENGTH = HTOLE16 (actual);
    		request->MOFFSET = HTOLE32 (offset);
    		if (sendpacket (channel, message, (ETHER_MIN_LEN - ETHER_CRC_LEN)) <= 0)
    		{
    			error (1, errno, CHANNEL_CANTSEND);
    		}
    		if (readpacket (channel, message, sizeof (* message)) <= 0)
    		{
    			error (1, errno, CHANNEL_CANTREAD);
    		}
    		if (UnwantedMessage (message, sizeof (* confirm), 0, (VS_RD_MOD | MMTYPE_CNF)))
    		{
    			actual = PLC_RECORD_SIZE;
    			offset = 0;
    			continue;
    		}
    		if (confirm->MSTATUS)
    		{
    			error (1, ECANCELED, PLC_WONTDOIT);
    		}
    		if (LE16TOH (confirm->MLENGTH) != actual)
    		{
    			error (1, ECANCELED, PLC_ERR_LENGTH);
    		}
    		if (LE32TOH (confirm->MOFFSET) != offset)
    		{
    			error (1, ECANCELED, PLC_ERR_OFFSET);
    		}
    		actual = LE16TOH (confirm->MLENGTH);
    		offset = LE32TOH (confirm->MOFFSET);
    		if (checksum32 (confirm->BUFFER, actual, confirm->CHKSUM))
    		{
    			error (1, ECANCELED, "Bad Packet Checksum");
    		}
    		if (offset == length)
    		{
    			struct pib_header * pib_header = (struct pib_header *) (confirm->BUFFER);
    			length = LE16TOH (pib_header->PIBLENGTH);
    		}
    		if ((offset + actual) > length)
    		{
    			actual = length - offset;
    		}
    		memcpy (buffer + offset, confirm->BUFFER, actual);
    		offset += actual;
    		extent -= actual;
    	}
    	while (offset < length);
    	return (offset);
    }

    #endif

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