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app-layer-enip-common.c
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app-layer-enip-common.c
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/* Copyright (C) 2015 Open Information Security Foundation
*
* You can copy, redistribute or modify this Program under the terms of
* the GNU General Public License version 2 as published by the Free
* Software Foundation.
*
* This program 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
* version 2 along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
/**
* \file
*
* \author Kevin Wong <[email protected]>
*
* App-layer parser for ENIP protocol common code
*
*/
#include "suricata-common.h"
#include "util-unittest.h"
#include "util-unittest-helper.h"
#include "detect-parse.h"
#include "detect-engine.h"
#include "util-byte.h"
#include "pkt-var.h"
#include "util-profiling.h"
#include "app-layer-enip-common.h"
/**
* \brief Extract 8 bits and move up the offset
* @param res
* @param input
* @param offset
*/
int ENIPExtractUint8(uint8_t *res, uint8_t *input, uint16_t *offset, uint32_t input_len)
{
if (*offset > (input_len - sizeof(uint8_t)))
{
SCLogDebug("ENIPExtractUint8: Parsing beyond payload length");
return 0;
}
*res = *(input + *offset);
*offset += sizeof(uint8_t);
return 1;
}
/**
* \brief Extract 16 bits and move up the offset
* @param res
* @param input
* @param offset
*/
int ENIPExtractUint16(uint16_t *res, uint8_t *input, uint16_t *offset, uint32_t input_len)
{
if (*offset > (input_len - sizeof(uint16_t)))
{
SCLogDebug("ENIPExtractUint16: Parsing beyond payload length");
return 0;
}
ByteExtractUint16(res, BYTE_LITTLE_ENDIAN, sizeof(uint16_t),
(const uint8_t *) (input + *offset));
*offset += sizeof(uint16_t);
return 1;
}
/**
* \brief Extract 32 bits and move up the offset
* @param res
* @param input
* @param offset
*/
int ENIPExtractUint32(uint32_t *res, uint8_t *input, uint16_t *offset, uint32_t input_len)
{
if (*offset > (input_len - sizeof(uint32_t)))
{
SCLogDebug("ENIPExtractUint32: Parsing beyond payload length");
return 0;
}
ByteExtractUint32(res, BYTE_LITTLE_ENDIAN, sizeof(uint32_t),
(const uint8_t *) (input + *offset));
*offset += sizeof(uint32_t);
return 1;
}
/**
* \brief Extract 64 bits and move up the offset
* @param res
* @param input
* @param offset
*/
int ENIPExtractUint64(uint64_t *res, uint8_t *input, uint16_t *offset, uint32_t input_len)
{
if (*offset > (input_len - sizeof(uint64_t)))
{
SCLogDebug("ENIPExtractUint64: Parsing beyond payload length");
return 0;
}
ByteExtractUint64(res, BYTE_LITTLE_ENDIAN, sizeof(uint64_t),
(const uint8_t *) (input + *offset));
*offset += sizeof(uint64_t);
return 1;
}
/**
* \brief Create service entry, add to transaction
* @param tx Transaction
* @return service entry
*/
static CIPServiceEntry *CIPServiceAlloc(ENIPTransaction *tx)
{
CIPServiceEntry *svc = (CIPServiceEntry *) SCCalloc(1,
sizeof(CIPServiceEntry));
if (unlikely(svc == NULL))
return NULL;
memset(svc, 0x00, sizeof(CIPServiceEntry));
TAILQ_INIT(&svc->segment_list);
TAILQ_INIT(&svc->attrib_list);
TAILQ_INSERT_TAIL(&tx->service_list, svc, next);
tx->service_count++;
return svc;
}
/**
* \brief Delete service entry
*/
void CIPServiceFree(void *s)
{
SCEnter();
if (s)
{
CIPServiceEntry *svc = (CIPServiceEntry *) s;
SegmentEntry *seg = NULL;
while ((seg = TAILQ_FIRST(&svc->segment_list)))
{
TAILQ_REMOVE(&svc->segment_list, seg, next);
SCFree(seg);
}
AttributeEntry *attr = NULL;
while ((attr = TAILQ_FIRST(&svc->attrib_list)))
{
TAILQ_REMOVE(&svc->attrib_list, attr, next);
SCFree(attr);
}
SCFree(s);
}
SCReturn;
}
/**
* \brief Decode ENIP Encapsulation Header
* @param input, input_len data stream
* @param enip_data stores data from Packet
* @return 1 Packet ok
* @return 0 Packet has errors
*/
int DecodeENIPPDU(uint8_t *input, uint32_t input_len,
ENIPTransaction *enip_data)
{
int ret = 1;
uint16_t offset = 0; //byte offset
//Decode Encapsulation Header
uint16_t cmd;
uint16_t len;
uint32_t session;
uint32_t status;
uint64_t context;
uint32_t option;
if (ENIPExtractUint16(&cmd, input, &offset, input_len) != 1)
{
return 0;
}
if (ENIPExtractUint16(&len, input, &offset, input_len) != 1)
{
return 0;
}
if (ENIPExtractUint32(&session, input, &offset, input_len) != 1)
{
return 0;
}
if (ENIPExtractUint32(&status, input, &offset, input_len) != 1)
{
return 0;
}
if (ENIPExtractUint64(&context, input, &offset, input_len) != 1)
{
return 0;
}
if (ENIPExtractUint32(&option, input, &offset, input_len) != 1)
{
return 0;
}
enip_data->header.command = cmd;
enip_data->header.length = len;
enip_data->header.session = session;
enip_data->header.status = status;
enip_data->header.context = context;
enip_data->header.option = option;
switch (enip_data->header.command)
{
case NOP:
SCLogDebug("DecodeENIP - NOP");
break;
case LIST_SERVICES:
SCLogDebug("DecodeENIP - LIST_SERVICES");
break;
case LIST_IDENTITY:
SCLogDebug("DecodeENIP - LIST_IDENTITY");
break;
case LIST_INTERFACES:
SCLogDebug("DecodeENIP - LIST_INTERFACES");
break;
case REGISTER_SESSION:
SCLogDebug("DecodeENIP - REGISTER_SESSION");
break;
case UNREGISTER_SESSION:
SCLogDebug("DecodeENIP - UNREGISTER_SESSION");
break;
case SEND_RR_DATA:
SCLogDebug(
"DecodeENIP - SEND_RR_DATA - parse Common Packet Format");
ret = DecodeCommonPacketFormatPDU(input, input_len, enip_data,
offset);
break;
case SEND_UNIT_DATA:
SCLogDebug(
"DecodeENIP - SEND UNIT DATA - parse Common Packet Format");
ret = DecodeCommonPacketFormatPDU(input, input_len, enip_data,
offset);
break;
case INDICATE_STATUS:
SCLogDebug("DecodeENIP - INDICATE_STATUS");
break;
case CANCEL:
SCLogDebug("DecodeENIP - CANCEL");
break;
default:
SCLogDebug("DecodeENIP - UNSUPPORTED COMMAND 0x%x",
enip_data->header.command);
}
return ret;
}
/**
* \brief Decode Common Packet Format
* @param input, input_len data stream
* @param enip_data stores data from Packet
* @param offset current point in the packet
* @return 1 Packet ok
* @return 0 Packet has errors
*/
int DecodeCommonPacketFormatPDU(uint8_t *input, uint32_t input_len,
ENIPTransaction *enip_data, uint16_t offset)
{
if (enip_data->header.length < sizeof(ENIPEncapDataHdr))
{
SCLogDebug("DecodeCommonPacketFormat: Malformed ENIP packet");
return 0;
}
uint32_t handle;
uint16_t timeout;
uint16_t count;
if (ENIPExtractUint32(&handle, input, &offset, input_len) != 1)
{
return 0;
}
if (ENIPExtractUint16(&timeout, input, &offset, input_len) != 1)
{
return 0;
}
if (ENIPExtractUint16(&count, input, &offset, input_len) != 1)
{
return 0;
}
enip_data->encap_data_header.interface_handle = handle;
enip_data->encap_data_header.timeout = timeout;
enip_data->encap_data_header.item_count = count;
uint16_t address_type;
uint16_t address_length; //length of connection id in bytes
uint32_t address_connectionid = 0;
uint32_t address_sequence = 0;
if (ENIPExtractUint16(&address_type, input, &offset, input_len) != 1)
{
return 0;
}
if (ENIPExtractUint16(&address_length, input, &offset, input_len) != 1)
{
return 0;
}
//depending on addr type, get connection id, sequence if needed. Can also use addr length too?
if (address_type == CONNECTION_BASED)
{ //get 4 byte connection id
if (ENIPExtractUint32(&address_connectionid, input, &offset, input_len) != 1)
{
return 0;
}
} else if (address_type == SEQUENCE_ADDR_ITEM)
{ // get 4 byte connection id and 4 byte sequence
if (ENIPExtractUint32(&address_connectionid, input, &offset, input_len) != 1)
{
return 0;
}
if (ENIPExtractUint32(&address_sequence, input, &offset, input_len) != 1)
{
return 0;
}
}
enip_data->encap_addr_item.type = address_type;
enip_data->encap_addr_item.length = address_length;
enip_data->encap_addr_item.conn_id = address_connectionid;
enip_data->encap_addr_item.sequence_num = address_sequence;
uint16_t data_type;
uint16_t data_length; //length of data in bytes
uint16_t data_sequence_count;
if (ENIPExtractUint16(&data_type, input, &offset, input_len) != 1)
{
return 0;
}
if (ENIPExtractUint16(&data_length, input, &offset, input_len) != 1)
{
return 0;
}
enip_data->encap_data_item.type = data_type;
enip_data->encap_data_item.length = data_length;
if (enip_data->encap_data_item.type == CONNECTED_DATA_ITEM)
{ //connected data items have seq number
if (ENIPExtractUint16(&data_sequence_count, input, &offset, input_len) != 1)
{
return 0;
}
enip_data->encap_data_item.sequence_count = data_sequence_count;
}
switch (enip_data->encap_data_item.type)
{
case CONNECTED_DATA_ITEM:
SCLogDebug(
"DecodeCommonPacketFormat - CONNECTED DATA ITEM - parse CIP");
DecodeCIPPDU(input, input_len, enip_data, offset);
break;
case UNCONNECTED_DATA_ITEM:
SCLogDebug("DecodeCommonPacketFormat - UNCONNECTED DATA ITEM");
DecodeCIPPDU(input, input_len, enip_data, offset);
break;
default:
SCLogDebug("DecodeCommonPacketFormat - UNKNOWN TYPE 0x%x",
enip_data->encap_data_item.type);
return 0;
}
return 1;
}
/**
* \brief Decode CIP packet
* @param input, input_len data stream
* @param enip_data stores data from Packet
* @param offset current point in the packet
* @return 1 Packet ok
* @return 0 Packet has errors
*/
int DecodeCIPPDU(uint8_t *input, uint32_t input_len,
ENIPTransaction *enip_data, uint16_t offset)
{
int ret = 1;
if (enip_data->encap_data_item.length == 0)
{
SCLogDebug("DecodeCIP: No CIP Data");
return 0;
}
if (offset > (input_len - sizeof(uint8_t)))
{
SCLogDebug("DecodeCIP: Parsing beyond payload length");
return 0;
}
uint8_t service = 0;
service = *(input + offset);
//SCLogDebug("CIP Service 0x%x", service);
//use service code first bit to determine request/response, no need to save or push offset
if (service >> 7)
{
ret = DecodeCIPResponsePDU(input, input_len, enip_data, offset);
} else
{
ret = DecodeCIPRequestPDU(input, input_len, enip_data, offset);
}
return ret;
}
/**
* \brief Decode CIP Request
* @param input, input_len data stream
* @param enip_data stores data from Packet
* @param offset current point in the packet
* @return 1 Packet ok
* @return 0 Packet has errors
*/
int DecodeCIPRequestPDU(uint8_t *input, uint32_t input_len,
ENIPTransaction *enip_data, uint16_t offset)
{
int ret = 1;
if (enip_data->encap_data_item.length < sizeof(CIPReqHdr))
{
SCLogDebug("DecodeCIPRequest - Malformed CIP Data");
return 0;
}
uint8_t service; //<-----CIP SERVICE
uint8_t path_size;
if (ENIPExtractUint8(&service, input, &offset, input_len) != 1)
{
return 0;
}
if (ENIPExtractUint8(&path_size, input, &offset, input_len) != 1)
{
return 0;
}
if (service > MAX_CIP_SERVICE)
{ // service codes of value 0x80 or greater are not permitted because in the CIP protocol the highest order bit is used to flag request(0)/response(1)
SCLogDebug("DecodeCIPRequest - INVALID CIP SERVICE 0x%x", service);
return 0;
}
//reached maximum number of services
if (enip_data->service_count > 32)
{
SCLogDebug("DecodeCIPRequest: Maximum services reached");
return 0;
}
//save CIP data
CIPServiceEntry *node = CIPServiceAlloc(enip_data);
if (node == NULL)
{
SCLogDebug("DecodeCIPRequest: Unable to create CIP service");
return 0;
}
node->direction = 0;
node->service = service;
node->request.path_size = path_size;
node->request.path_offset = offset;
// SCLogDebug("DecodeCIPRequestPDU: service 0x%x size %d", node->service,
// node->request.path_size);
DecodeCIPRequestPathPDU(input, input_len, node, offset);
offset += path_size * sizeof(uint16_t); //move offset past pathsize
//list of CIP services is large and can be vendor specific, store CIP service anyways and let the rule decide the action
switch (service)
{
case CIP_RESERVED:
SCLogDebug("DecodeCIPRequest - CIP_RESERVED");
break;
case CIP_GET_ATTR_ALL:
SCLogDebug("DecodeCIPRequest - CIP_GET_ATTR_ALL");
break;
case CIP_GET_ATTR_LIST:
SCLogDebug("DecodeCIPRequest - CIP_GET_ATTR_LIST");
break;
case CIP_SET_ATTR_LIST:
SCLogDebug("DecodeCIPRequest - CIP_SET_ATTR_LIST");
break;
case CIP_RESET:
SCLogDebug("DecodeCIPRequest - CIP_RESET");
break;
case CIP_START:
SCLogDebug("DecodeCIPRequest - CIP_START");
break;
case CIP_STOP:
SCLogDebug("DecodeCIPRequest - CIP_STOP");
break;
case CIP_CREATE:
SCLogDebug("DecodeCIPRequest - CIP_CREATE");
break;
case CIP_DELETE:
SCLogDebug("DecodeCIPRequest - CIP_DELETE");
break;
case CIP_MSP:
SCLogDebug("DecodeCIPRequest - CIP_MSP");
DecodeCIPRequestMSPPDU(input, input_len, enip_data, offset);
break;
case CIP_APPLY_ATTR:
SCLogDebug("DecodeCIPRequest - CIP_APPLY_ATTR");
break;
case CIP_KICK_TIMER:
SCLogDebug("DecodeCIPRequest - CIP_KICK_TIMER");
break;
case CIP_OPEN_CONNECTION:
SCLogDebug("DecodeCIPRequest - CIP_OPEN_CONNECTION");
break;
case CIP_CHANGE_START:
SCLogDebug("DecodeCIPRequest - CIP_CHANGE_START");
break;
case CIP_GET_STATUS:
SCLogDebug("DecodeCIPRequest - CIP_GET_STATUS");
break;
default:
SCLogDebug("DecodeCIPRequest - CIP SERVICE 0x%x", service);
}
return ret;
}
/**
* \brief Deocde CIP Request Path
* @param input, input_len data stream
* @param enip_data stores data from Packet
* @param offset current point in the packet
* @param cipserviced the cip service rule
* @return 1 Packet matches
* @return 0 Packet not match
*/
int DecodeCIPRequestPathPDU(uint8_t *input, uint32_t input_len,
CIPServiceEntry *node, uint16_t offset)
{
//SCLogDebug("DecodeCIPRequestPath: service 0x%x size %d length %d",
// node->service, node->request.path_size, input_len);
if (node->request.path_size < 1)
{
//SCLogDebug("DecodeCIPRequestPath: empty path or CIP Response");
return 0;
}
int bytes_remain = node->request.path_size;
uint8_t segment;
uint8_t reserved; //unused byte reserved by ODVA
//8 bit fields
uint8_t req_path_class8;
uint8_t req_path_instance8;
uint8_t req_path_attr8;
//16 bit fields
uint16_t req_path_class16;
uint16_t req_path_instance16;
uint16_t class = 0;
SegmentEntry *seg = NULL;
while (bytes_remain > 0)
{
if (ENIPExtractUint8(&segment, input, &offset, input_len) != 1)
{
return 0;
}
switch (segment)
{ //assume order is class then instance. Can have multiple
case PATH_CLASS_8BIT:
if (ENIPExtractUint8(&req_path_class8, input, &offset, input_len) != 1)
{
return 0;
}
class = (uint16_t) req_path_class8;
SCLogDebug("DecodeCIPRequestPathPDU: 8bit class 0x%x", class);
seg = SCMalloc(sizeof(SegmentEntry));
if (unlikely(seg == NULL))
return 0;
seg->segment = segment;
seg->value = class;
TAILQ_INSERT_TAIL(&node->segment_list, seg, next);
bytes_remain--;
break;
case PATH_INSTANCE_8BIT:
if (ENIPExtractUint8(&req_path_instance8, input, &offset, input_len) != 1)
{
return 0;
}
//skip instance, don't need to store
bytes_remain--;
break;
case PATH_ATTR_8BIT: //single attribute
if (ENIPExtractUint8(&req_path_attr8, input, &offset, input_len) != 1)
{
return 0;
}
//uint16_t attrib = (uint16_t) req_path_attr8;
//SCLogDebug("DecodeCIPRequestPath: 8bit attr 0x%x", attrib);
seg = SCMalloc(sizeof(SegmentEntry));
if (unlikely(seg == NULL))
return 0;
seg->segment = segment;
seg->value = class;
TAILQ_INSERT_TAIL(&node->segment_list, seg, next);
bytes_remain--;
break;
case PATH_CLASS_16BIT:
if (ENIPExtractUint8(&reserved, input, &offset, input_len) != 1) //skip reserved
{
return 0;
}
if (ENIPExtractUint16(&req_path_class16, input, &offset, input_len) != 1)
{
return 0;
}
class = req_path_class16;
SCLogDebug("DecodeCIPRequestPath: 16bit class 0x%x", class);
seg = SCMalloc(sizeof(SegmentEntry));
if (unlikely(seg == NULL))
return 0;
seg->segment = segment;
seg->value = class;
TAILQ_INSERT_TAIL(&node->segment_list, seg, next);
if (bytes_remain >= 2)
{
bytes_remain = bytes_remain - 2;
} else
{
bytes_remain = 0;
}
break;
case PATH_INSTANCE_16BIT:
if (ENIPExtractUint8(&reserved, input, &offset, input_len) != 1) // skip reserved
{
return 0;
}
if (ENIPExtractUint16(&req_path_instance16, input, &offset, input_len) != 1)
{
return 0;
}
//skip instance, don't need to store
if (bytes_remain >= 2)
{
bytes_remain = bytes_remain - 2;
} else
{
bytes_remain = 0;
}
break;
default:
SCLogDebug(
"DecodeCIPRequestPath: UNKNOWN SEGMENT 0x%x service 0x%x",
segment, node->service);
return 0;
}
}
if ((node->service == CIP_SET_ATTR_LIST) || (node->service
== CIP_GET_ATTR_LIST))
{
uint16_t attr_list_count;
uint16_t attribute;
//parse get/set attribute list
if (ENIPExtractUint16(&attr_list_count, input, &offset, input_len) != 1)
{
return 0;
}
SCLogDebug("DecodeCIPRequestPathPDU: attribute list count %d",
attr_list_count);
for (int i = 0; i < attr_list_count; i++)
{
if (ENIPExtractUint16(&attribute, input, &offset, input_len) != 1)
{
return 0;
}
SCLogDebug("DecodeCIPRequestPathPDU: attribute %d", attribute);
//save attrs
AttributeEntry *attr = SCMalloc(sizeof(AttributeEntry));
if (unlikely(attr == NULL))
return 0;
attr->attribute = attribute;
TAILQ_INSERT_TAIL(&node->attrib_list, attr, next);
}
}
return 1;
}
/**
* \brief Decode CIP Response
* @param input, input_len data stream
* @param enip_data stores data from Packet
* @param offset current point in the packet
* @return 1 Packet ok
* @return 0 Packet has errors
*/
int DecodeCIPResponsePDU(uint8_t *input, uint32_t input_len,
ENIPTransaction *enip_data, uint16_t offset)
{
int ret = 1;
if (enip_data->encap_data_item.length < sizeof(CIPRespHdr))
{
SCLogDebug("DecodeCIPResponse - Malformed CIP Data");
return 0;
}
uint8_t service; //<----CIP SERVICE
uint8_t reserved; //unused byte reserved by ODVA
uint16_t status;
if (ENIPExtractUint8(&service, input, &offset, input_len) != 1)
{
return 0;
}
if (ENIPExtractUint8(&reserved, input, &offset, input_len) != 1)
{
return 0;
}
if (ENIPExtractUint16(&status, input, &offset, input_len) != 1)
{
return 0;
}
//SCLogDebug("DecodeCIPResponse: service 0x%x",service);
service &= 0x7f; //strip off top bit to get service code. Responses have first bit as 1
SCLogDebug("CIP service 0x%x status 0x%x", service, status);
//reached maximum number of services
if (enip_data->service_count > 32)
{
SCLogDebug("DecodeCIPRequest: Maximum services reached");
return 0;
}
//save CIP data
CIPServiceEntry *node = CIPServiceAlloc(enip_data);
if (node == NULL)
{
SCLogDebug("DecodeCIPRequest: Unable to create CIP service");
return 0;
}
node->direction = 1;
node->service = service;
node->response.status = status;
SCLogDebug("DecodeCIPResponsePDU: service 0x%x size %d", node->service,
node->request.path_size);
//list of CIP services is large and can be vendor specific, store CIP service anyways and let the rule decide the action
switch (service)
{
case CIP_RESERVED:
SCLogDebug("DecodeCIPResponse - CIP_RESERVED");
break;
case CIP_GET_ATTR_ALL:
SCLogDebug("DecodeCIPResponse - CIP_GET_ATTR_ALL");
break;
case CIP_GET_ATTR_LIST:
SCLogDebug("DecodeCIPResponse - CIP_GET_ATTR_LIST");
break;
case CIP_SET_ATTR_LIST:
SCLogDebug("DecodeCIPResponse - CIP_SET_ATTR_LIST");
break;
case CIP_RESET:
SCLogDebug("DecodeCIPResponse - CIP_RESET");
break;
case CIP_START:
SCLogDebug("DecodeCIPResponse - CIP_START");
break;
case CIP_STOP:
SCLogDebug("DecodeCIPResponse - CIP_STOP");
break;
case CIP_CREATE:
SCLogDebug("DecodeCIPResponse - CIP_CREATE");
break;
case CIP_DELETE:
SCLogDebug("DecodeCIPResponse - CIP_DELETE");
break;
case CIP_MSP:
SCLogDebug("DecodeCIPResponse - CIP_MSP");
DecodeCIPResponseMSPPDU(input, input_len, enip_data, offset);
break;
case CIP_APPLY_ATTR:
SCLogDebug("DecodeCIPResponse - CIP_APPLY_ATTR");
break;
case CIP_KICK_TIMER:
SCLogDebug("DecodeCIPResponse - CIP_KICK_TIMER");
break;
case CIP_OPEN_CONNECTION:
SCLogDebug("DecodeCIPResponse - CIP_OPEN_CONNECTION");
break;
case CIP_CHANGE_START:
SCLogDebug("DecodeCIPResponse - CIP_CHANGE_START");
break;
case CIP_GET_STATUS:
SCLogDebug("DecodeCIPResponse - CIP_GET_STATUS");
break;
default:
SCLogDebug("DecodeCIPResponse - CIP SERVICE 0x%x", service);
}
return ret;
}
/**
* \brief Decode CIP Request Multi Service Packet
* @param input, input_len data stream
* @param enip_data stores data from Packet
* @param offset current point in the packet
* @return 1 Packet ok
* @return 0 Packet has errors
*/
int DecodeCIPRequestMSPPDU(uint8_t *input, uint32_t input_len,
ENIPTransaction *enip_data, uint16_t offset)
{
int ret = 1;
if (offset >= (input_len - sizeof(uint16_t)))
{
SCLogDebug("DecodeCIPRequestMSPPDU: Parsing beyond payload length");
return 0;
}
//use temp_offset just to grab the service offset, don't want to use and push offset
uint16_t temp_offset = offset;
uint16_t num_services;
ByteExtractUint16(&num_services, BYTE_LITTLE_ENDIAN, sizeof(uint16_t),
(const uint8_t *) (input + temp_offset));
temp_offset += sizeof(uint16_t);
//SCLogDebug("DecodeCIPRequestMSP number of services %d",num_services);
for (int svc = 1; svc < num_services + 1; svc++)
{
if (temp_offset >= (input_len - sizeof(uint16_t)))
{
SCLogDebug("DecodeCIPRequestMSPPDU: Parsing beyond payload length");
return 0;
}
uint16_t svc_offset; //read set of service offsets
ByteExtractUint16(&svc_offset, BYTE_LITTLE_ENDIAN, sizeof(uint16_t),
(const uint8_t *) (input + temp_offset));
temp_offset += sizeof(uint16_t);
//SCLogDebug("parseCIPRequestMSP service %d offset %d",svc, svc_offset);
DecodeCIPPDU(input, input_len, enip_data, offset + svc_offset); //parse CIP at found offset
}
return ret;
}
/**
* \brief Decode CIP Response MultiService Packet.
* @param input, input_len data stream
* @param enip_data stores data from Packet
* @param offset current point in the packet
* @return 1 Packet ok
* @return 0 Packet has errors
*/
int DecodeCIPResponseMSPPDU(uint8_t *input, uint32_t input_len,
ENIPTransaction *enip_data, uint16_t offset)
{
int ret = 1;
if (offset >= (input_len - sizeof(uint16_t)))
{
SCLogDebug("DecodeCIPResponseMSPPDU: Parsing beyond payload length");
return 0;
}
//use temp_offset just to grab the service offset, don't want to use and push offset
uint16_t temp_offset = offset;
uint16_t num_services;
ByteExtractUint16(&num_services, BYTE_LITTLE_ENDIAN, sizeof(uint16_t),
(const uint8_t *) (input + temp_offset));
temp_offset += sizeof(uint16_t);
//SCLogDebug("DecodeCIPResponseMSP number of services %d", num_services);
for (int svc = 0; svc < num_services; svc++)
{
if (temp_offset >= (input_len - sizeof(uint16_t)))
{
SCLogDebug("DecodeCIPResponseMSP: Parsing beyond payload length");
return 0;
}
uint16_t svc_offset; //read set of service offsets
ByteExtractUint16(&svc_offset, BYTE_LITTLE_ENDIAN, sizeof(uint16_t),
(const uint8_t *) (input + temp_offset));
temp_offset += sizeof(uint16_t);
//SCLogDebug("parseCIPResponseMSP service %d offset %d", svc, svc_offset);
DecodeCIPPDU(input, input_len, enip_data, offset + svc_offset); //parse CIP at found offset
}
return ret;
}