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