ostinato/common/pdmlprotocol.cpp
Srivats P dbdeee2a6f Add option to recalculate cksums during pcap import
Recalculate cksum is now the default.

This behaviour change has been done to facilitate rewriting packet
fields post PCAP import using the new Find & Replace feature. Without
this any change in fields may cause incorrect checksums.

The earlier rationale for retaining the checksums in the PCAP file
during import was to ensure replayed packet was same as the one in the
PCAP file.

User now has a choice with this option.
2021-12-11 19:27:44 +05:30

255 lines
7.2 KiB
C++

/*
Copyright (C) 2011 Srivats P.
This file is part of "Ostinato"
This is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
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
along with this program. If not, see <http://www.gnu.org/licenses/>
*/
#include "pdmlprotocol.h"
/*!
\class PdmlProtocol
PdmlProtocol is the base class which provides the interface for all
PDML decode helper protocols
All Pdml helper classes derived from PdmlProtocol MUST register
themselves with PdmlReader. When PdmlReader encounters a 'proto' tag
in the PDML during parsing, it instantiates the corresponding helper
PdmlProtocol class and calls its methods to decode the protocol.
A subclass MUST initialize the following inherited protected variables
in its constructor -
- ostProtoId_
- fieldMap_
A subclass typically needs to reimplement the following methods -
- createInstance()
Depending on certain conditions, subclasses may need to reimplement
the following additional methods -
- unknownFieldHandler()
- preProtocolHandler()
- postProtocolHandler()
See the description of the methods for more information.
Use the SamplePdmlProtocol implementation as boilerplate code and
for guidelines and tips
*/
/*!
Constructs the PdmlProtocol
*/
PdmlProtocol::PdmlProtocol()
{
ostProtoId_ = -1;
}
/*!
Destroys the PdmlProtocol
*/
PdmlProtocol::~PdmlProtocol()
{
}
/*!
Allocates and returns a new instance of the class
Caller is responsible for freeing up after use. Subclasses MUST implement
this function and register it with PdmlReader
*/
PdmlProtocol* PdmlProtocol::createInstance()
{
return new PdmlProtocol();
}
/*!
Returns the protocol's field number as defined in message 'Protocol', enum 'k'
(file: protocol.proto)
*/
int PdmlProtocol::ostProtoId() const
{
return ostProtoId_;
}
/*!
Returns true if name is a 'known' field that can be directly mapped
to the protobuf field
*/
bool PdmlProtocol::hasField(QString name) const
{
return fieldMap_.contains(name);
}
/*!
Returns the protocol's protobuf field number corresponding to name
*/
int PdmlProtocol::fieldId(QString name) const
{
return fieldMap_.value(name);
}
void PdmlProtocol::setRecalculateCksum(bool recalculate)
{
overrideCksum_ = !recalculate;
}
/*!
This method is called by PdmlReader before any fields within the protocol
are processed. All attributes associated with the 'proto' tag in the PDML
are passed to this method
Use this method to do any special handling that may be required for
preprocessing
*/
void PdmlProtocol::preProtocolHandler(QString /*name*/,
const QXmlStreamAttributes& /*attributes*/,
int /*expectedPos*/, OstProto::Protocol* /*pbProto*/,
OstProto::Stream* /*stream*/)
{
return; // do nothing!
}
/*!
This method is called by PdmlReader when it encounters a nested
protocol in the PDML i.e. a protocol within a protocol or a protocol
within a field
This is a notification to the protocol that protocol processing will
be ending prematurely. postProtocolHandler() will still be called in
such cases.
*/
void PdmlProtocol::prematureEndHandler(int /*pos*/,
OstProto::Protocol* /*pbProto*/, OstProto::Stream* /*stream*/)
{
return; // do nothing!
}
/*!
This method is called by PdmlReader after all fields within the protocol
are processed.
Use this method to do any special handling that may be required for
postprocessing
*/
void PdmlProtocol::postProtocolHandler(OstProto::Protocol* /*pbProto*/,
OstProto::Stream* /*stream*/)
{
return; // do nothing!
}
/*!
This method is called by PdmlReader for each field in the protocol
Depending on whether it is a known or unknown field, the virtual methods
knownFieldHandler() and unknownFieldHandler() are invoked
*/
void PdmlProtocol::fieldHandler(QString name,
const QXmlStreamAttributes &attributes,
OstProto::Protocol *pbProto, OstProto::Stream *stream)
{
if (hasField(name))
{
QString valueHexStr = attributes.value("value").toString();
qDebug("\t(KNOWN) fieldName:%s, value:%s",
qPrintable(name),
qPrintable(valueHexStr));
if (!valueHexStr.isEmpty())
knownFieldHandler(name, valueHexStr, pbProto);
}
else
{
int pos = -1;
int size = -1;
if (!attributes.value("pos").isEmpty())
pos = attributes.value("pos").toString().toInt();
if (!attributes.value("size").isEmpty())
size = attributes.value("size").toString().toInt();
qDebug("\t(UNKNOWN) fieldName:%s, pos:%d, size:%d",
qPrintable(name), pos, size);
unknownFieldHandler(name, pos, size, attributes, pbProto, stream);
}
}
/*!
Handles a 'known' field
Uses protobuf reflection interface to set the protobuf field name to
valueHexStr as per the field's datatype
*/
void PdmlProtocol::knownFieldHandler(QString name, QString valueHexStr,
OstProto::Protocol *pbProto)
{
const google::protobuf::Reflection *protoRefl = pbProto->GetReflection();
const google::protobuf::FieldDescriptor *extDesc =
protoRefl->FindKnownExtensionByNumber(ostProtoId());
google::protobuf::Message *msg =
protoRefl->MutableMessage(pbProto,extDesc);
const google::protobuf::Reflection *msgRefl = msg->GetReflection();
const google::protobuf::FieldDescriptor *fieldDesc =
msg->GetDescriptor()->FindFieldByNumber(fieldId(name));
bool isOk;
Q_ASSERT(fieldDesc != NULL);
switch(fieldDesc->cpp_type())
{
case google::protobuf::FieldDescriptor::CPPTYPE_BOOL:
msgRefl->SetBool(msg, fieldDesc, bool(valueHexStr.toUInt(&isOk)));
break;
case google::protobuf::FieldDescriptor::CPPTYPE_ENUM: // TODO
case google::protobuf::FieldDescriptor::CPPTYPE_UINT32:
msgRefl->SetUInt32(msg, fieldDesc,
valueHexStr.toUInt(&isOk, kBaseHex));
break;
case google::protobuf::FieldDescriptor::CPPTYPE_UINT64:
msgRefl->SetUInt64(msg, fieldDesc,
valueHexStr.toULongLong(&isOk, kBaseHex));
break;
case google::protobuf::FieldDescriptor::CPPTYPE_STRING:
{
QByteArray hexVal = QByteArray::fromHex(valueHexStr.toUtf8());
std::string str(hexVal.constData(), hexVal.size());
msgRefl->SetString(msg, fieldDesc, str);
break;
}
default:
qDebug("%s: unhandled cpptype = %d", __FUNCTION__,
fieldDesc->cpp_type());
}
}
/*!
Handles a 'unknown' field
The default implementation does nothing. Subclasses may need to implement
this if the protocol contains 'unknown' fields.
*/
void PdmlProtocol::unknownFieldHandler(QString /*name*/,
int /*pos*/, int /*size*/, const QXmlStreamAttributes& /*attributes*/,
OstProto::Protocol* /*pbProto*/, OstProto::Stream* /*stream*/)
{
return; // do nothing!
}