/***************************************************************************
* PacketElement.h -- The PacketElement Class is a generic class that *
* represents a protocol header or a part of a network packet. Many other *
* classes inherit from it (NetworkLayerElement, TransportLayerElement, *
* etc). *
* *
***********************IMPORTANT NMAP LICENSE TERMS************************
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***************************************************************************/
#ifndef PACKETELEMENT_H
#define PACKETELEMENT_H 1
#include "nping.h"
#include "nbase.h"
#include "output.h"
class PacketElement {
protected:
int length;
PacketElement *next; /**< Next PacketElement (next proto header) */
PacketElement *prev; /**< Prev PacketElement (previous proto header) */
public:
PacketElement();
~PacketElement();
/** This function MUST be overwritten on ANY class that inherits from
* this one. Otherwise getBinaryBuffer will fail */
virtual u8 * getBufferPointer(){
outFatal(VB_1,"getBufferPointer(): Attempting to use superclass PacketElement method.\n");
return NULL;
} /* End of getBufferPointer() */
/** Returns a buffer that contains the header of the packet + all the
* lower level headers and payload. Returned buffer should be ok to be
* passes to a send() call to be transferred trough a socket.
* @return a pointer to a free()able buffer that contains packet's binary
* data.
* @warning If there are linked elements, their getBinaryBuffer() method
* will be called recursively and the buffers that they return WILL be
* free()d as soon as we copy the data in our own allocated buffer.
* @warning Calls to this method may not ve very efficient since they
* always involved a few malloc()s and free()s. If you want efficiency
* use dumpToBinaryBuffer(); */
virtual u8 * getBinaryBuffer(){
u8 *ourbuff=NULL;
u8 *othersbuff=NULL;
u8 *totalbuff=NULL;
long otherslen=0;
/* Get our own buffer address */
if ( (ourbuff=getBufferPointer()) == NULL ){
outFatal(VB_1,"getBinaryBuffer(): Couldn't get own data pointer\n");
}
if( next != NULL ){ /* There is some other packet element */
othersbuff = next->getBinaryBuffer();
otherslen=next->getLen();
totalbuff=(u8 *)safe_zalloc(otherslen + length);
memcpy(totalbuff, ourbuff, length);
memcpy(totalbuff+length, othersbuff, otherslen);
free(othersbuff);
}else{
totalbuff=(u8 *)safe_zalloc(length);
memcpy(totalbuff, ourbuff, length);
}
return totalbuff;
} /* End of getBinaryBuffer() */
virtual int dumpToBinaryBuffer(u8* dst, int maxlen){
u8 *ourbuff=NULL;
long ourlength=0;
/* Get our own buffer address and length */
if ( (ourbuff=getBufferPointer()) == NULL || (ourlength=this->length) < 0 )
outFatal(VB_1,"getBinaryBuffer(): Couldn't get own data pointer\n");
/* Copy our part of the buffer */
if ( maxlen < ourlength )
outFatal(VB_1,"getBinaryBuffer(): Packet exceeds maximum length %d\n", maxlen);
memcpy( dst, ourbuff, ourlength);
/* If there are more elements, tell them to copy their part */
if( next!= NULL ){
next->dumpToBinaryBuffer(dst+ourlength, maxlen-ourlength);
}
return this->getLen();
} /* End of dumpToBinaryBuffer() */
/** Does the same as the previous one but it stores the length of the
* return buffer on the memory pointed by the supplied int pointer. */
virtual u8 * getBinaryBuffer(int *len){
u8 *buff = getBinaryBuffer();
if( len != NULL )
*len = getLen();
return buff;
} /* End of getBinaryBuffer() */
/** Returns the lenght of this PacketElement + the length of all the
* PacketElements that are next to it (are linked trough the "next"
* attribute). So for example, if we have IPv4Header p1, linked to
* a TCPHeader p2, representing a simple TCP SYN with no options,
* a call to p1.getLen() will return 20 (IP header with no options) + 20
* (TCP header with no options) = 40 bytes. */
virtual int getLen(){
/* If we have some other packet element linked, get its length */
if (next!=NULL)
return length + next->getLen();
else
return length;
} /* End of getLen() */
/** Returns the address of the next PacketElement that is linked to this */
virtual PacketElement *getNextElement(){
return next;
} /* End of getNextElement() */
/** Sets attribute next with the supplied pointer value.
* @warning Supplied pointer must point to a PacketElement object or
* an object that inherits from it. */
virtual int setNextElement(PacketElement *n){
next=n;
return OP_SUCCESS;
} /* End of setNextElement() */
/** Returns the address of the previous PacketElement that is linked to
* this one.
* @warning In many cases this function will return NULL since there is
* a high probability that the user of this class does not link
* PacketElements in both directions. Normally one would set attribute
* "next" of an IPHeader object to the TCPHeader that follows it, but
* not the other way around. */
virtual PacketElement *getPrevElement(){
return prev;
} /* End of getPrevElement() */
};
#endif