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/***************************************************************************
* FragmentHeader.cc -- The FragmentHeader Class represents an IPv6 *
* Hop-by-Hop extension header. *
***********************IMPORTANT NMAP LICENSE TERMS************************
*
* The Nmap Security Scanner is (C) 1996-2023 Nmap Software LLC ("The Nmap
* Project"). Nmap is also a registered trademark of the Nmap Project.
*
* This program is distributed under the terms of the Nmap Public Source
* License (NPSL). The exact license text applying to a particular Nmap
* release or source code control revision is contained in the LICENSE
* file distributed with that version of Nmap or source code control
* revision. More Nmap copyright/legal information is available from
* https://nmap.org/book/man-legal.html, and further information on the
* NPSL license itself can be found at https://nmap.org/npsl/ . This
* header summarizes some key points from the Nmap license, but is no
* substitute for the actual license text.
*
* Nmap is generally free for end users to download and use themselves,
* including commercial use. It is available from https://nmap.org.
*
* The Nmap license generally prohibits companies from using and
* redistributing Nmap in commercial products, but we sell a special Nmap
* OEM Edition with a more permissive license and special features for
* this purpose. See https://nmap.org/oem/
*
* If you have received a written Nmap license agreement or contract
* stating terms other than these (such as an Nmap OEM license), you may
* choose to use and redistribute Nmap under those terms instead.
*
* The official Nmap Windows builds include the Npcap software
* (https://npcap.com) for packet capture and transmission. It is under
* separate license terms which forbid redistribution without special
* permission. So the official Nmap Windows builds may not be redistributed
* without special permission (such as an Nmap OEM license).
*
* Source is provided to this software because we believe users have a
* right to know exactly what a program is going to do before they run it.
* This also allows you to audit the software for security holes.
*
* Source code also allows you to port Nmap to new platforms, fix bugs, and add
* new features. You are highly encouraged to submit your changes as a Github PR
* or by email to the dev@nmap.org mailing list for possible incorporation into
* the main distribution. Unless you specify otherwise, it is understood that
* you are offering us very broad rights to use your submissions as described in
* the Nmap Public Source License Contributor Agreement. This is important
* because we fund the project by selling licenses with various terms, and also
* because the inability to relicense code has caused devastating problems for
* other Free Software projects (such as KDE and NASM).
*
* The free version of Nmap 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. Warranties,
* indemnification and commercial support are all available through the
* Npcap OEM program--see https://nmap.org/oem/
*
***************************************************************************/
/* This code was originally part of the Nping tool. */
#include "FragmentHeader.h"
#include <assert.h>
/******************************************************************************/
/* CONTRUCTORS, DESTRUCTORS AND INITIALIZATION METHODS */
/******************************************************************************/
FragmentHeader::FragmentHeader() {
this->reset();
} /* End of FragmentHeader constructor */
FragmentHeader::~FragmentHeader() {
} /* End of FragmentHeader destructor */
/** Sets every attribute to its default value */
void FragmentHeader::reset(){
memset(&this->h, 0, sizeof(nping_ipv6_ext_fragment_hdr_t));
this->length=8;
} /* End of reset() */
/******************************************************************************/
/* PacketElement:: OVERWRITTEN METHODS */
/******************************************************************************/
/** @warning This method is essential for the superclass getBinaryBuffer()
* method to work. Do NOT change a thing unless you know what you're doing */
u8 *FragmentHeader::getBufferPointer(){
return (u8*)(&this->h);
} /* End of getBufferPointer() */
/** Stores supplied packet in the internal buffer so the information
* can be accessed using the standard get & set methods.
* @warning The FragmentHeader class is able to hold a maximum of
* sizeof(nping_icmpv6_hdr_t) bytes. If the supplied buffer is longer than
* that, only the first 1508 bytes will be stored in the internal buffer.
* @warning Supplied len MUST be at least 8 bytes (min ICMPv6 header length).
* @return OP_SUCCESS on success and OP_FAILURE in case of error */
int FragmentHeader::storeRecvData(const u8 *buf, size_t len){
if(buf==NULL || len<FRAGMENT_HEADER_LEN){
this->length=0;
return OP_FAILURE;
}else{
int stored_len = MIN(FRAGMENT_HEADER_LEN, len);
this->reset(); /* Re-init the object, just in case the caller had used it already */
this->length=stored_len;
memcpy(&(this->h), buf, stored_len);
}
return OP_SUCCESS;
} /* End of storeRecvData() */
/* Returns a protocol identifier. This is used by packet parsing funtions
* that return linked lists of PacketElement objects, to determine the protocol
* the object represents. */
int FragmentHeader::protocol_id() const {
return HEADER_TYPE_IPv6_FRAG;
} /* End of protocol_id() */
/** Determines if the data stored in the object after an storeRecvData() call
* is valid and safe to use. This mainly checks the length of the data but may
* also test the value of certain protocol fields to ensure their correctness.
* @return the length, in bytes, of the header, if its found to be valid or
* OP_FAILURE (-1) otherwise. */
int FragmentHeader::validate(){
/* Check the object's length makes sense*/
if(this->length != FRAGMENT_HEADER_LEN){
return OP_FAILURE;
}
/* There is not much to check for here, since header fields may take any
* value. We could certainly check the NextHeader value, but let's leave
* that for the class user. */
return this->length;
} /* End of validate() */
/** Prints the contents of the header and calls print() on the next protocol
* header in the chain (if there is any).
* @return OP_SUCCESS on success and OP_FAILURE in case of error. */
int FragmentHeader::print(FILE *output, int detail) const {
fprintf(output, "Fragment[%d, %d]", this->h.nh, this->h.id);
// TODO: @todo : Implement this
if(this->next!=NULL){
print_separator(output, detail);
next->print(output, detail);
}
return OP_SUCCESS;
} /* End of print() */
/******************************************************************************/
/* PROTOCOL-SPECIFIC METHODS */
/******************************************************************************/
/** Set Next Header field */
int FragmentHeader::setNextHeader(u8 val){
this->h.nh = val;
return OP_SUCCESS;
} /* End of setNextHeader() */
/** Returns next header id */
u8 FragmentHeader::getNextHeader(){
return this->h.nh;
} /* End of getNextHeader() */
/** Set Offset field */
int FragmentHeader::setOffset(u16 val){
this->h.off_res_flag[0]=(u8)(val >> 8);
this->h.off_res_flag[1]=(u8)((this->h.off_res_flag[1] & 0x7) | (val & ~0x7));
return OP_SUCCESS;
} /* End of setOffset() */
/** Returns fragment offset */
u16 FragmentHeader::getOffset(){
return ((this->h.off_res_flag[0] << 8) + this->h.off_res_flag[1]) & 0xfff8;
} /* End of getOffset() */
/* Sets the "More Fragments" flag. */
int FragmentHeader::setM(bool m_flag){
if(m_flag)
this->h.off_res_flag[1]= (u8)((this->h.off_res_flag[1] & ~0x01) | 0x01);
else
this->h.off_res_flag[1]= (u8)((this->h.off_res_flag[1] & ~0x1));
return OP_SUCCESS;
} /* End of setM() */
/* Returns true if the "More Fragments" flag is set; false otherwise. */
bool FragmentHeader::getM(){
return (this->h.off_res_flag[1] & 0x01);
} /* End of getM() */
/** Set the fragment identifier */
int FragmentHeader::setIdentification(u32 val){
this->h.id=htonl(val);
return OP_SUCCESS;
} /* End of setIdentification() */
/** Returns the fragment identifier*/
u32 FragmentHeader::getIdentification(){
return ntohl(this->h.id);
} /* End of getIdentification.() */
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