mirror of
https://github.com/nmap/nmap.git
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391 lines
17 KiB
C++
391 lines
17 KiB
C++
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/***************************************************************************
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* HopByHopHeader.cc -- The HopByHopHeader 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) 1996-2020 Insecure.Com 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 header *
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* summarizes some key points from the Nmap license, but is no substitute *
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* 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.org) 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 *
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* redistributed without special permission (such as an Nmap OEM *
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* 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, *
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* and add new features. You are highly encouraged to submit your *
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* changes as a Github PR or by email to the dev@nmap.org mailing list *
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* for possible incorporation into the main distribution. Unless you *
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* specify otherwise, it is understood that you are offering us very *
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* broad rights to use your submissions as described in the Nmap Public *
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* Source License Contributor Agreement. This is important because we *
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* fund the project by selling licenses with various terms, and also *
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* because the inability to relicense code has caused devastating *
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* problems for 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 "HopByHopHeader.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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HopByHopHeader::HopByHopHeader() {
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this->reset();
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} /* End of HopByHopHeader constructor */
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HopByHopHeader::~HopByHopHeader() {
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} /* End of HopByHopHeader destructor */
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/** Sets every attribute to its default value */
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void HopByHopHeader::reset(){
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memset(&this->h, 0, sizeof(nping_ipv6_ext_hopbyhop_hdr_t));
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curr_option=(u8*)this->h.options;
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this->length=2;
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this->addOption(EXTOPT_PADN, 4, (const u8*)"\x00\x00\x00\x00");
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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 *HopByHopHeader::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 HopByHopHeader 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 HopByHopHeader::storeRecvData(const u8 *buf, size_t len){
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if(buf==NULL || len<HOPBYHOP_MIN_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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/* Store the first 4 bytes, so we can access the HdrExtLen field. */
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memcpy(&(this->h), buf, 4);
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/* Check that the HdrExtLen field makes sense:
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* 1) Check that it carries as many octets as it claims
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* 2) Check that we don't exceed our internal storage space. */
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if( ((unsigned int)(this->h.len+1))*8 > len || (this->h.len+1)*8 > HOPBYHOP_MAX_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 mylen=(this->h.len+1)*8;
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this->reset();
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this->length=mylen;
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memcpy(&(this->h), buf, this->length);
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return OP_SUCCESS;
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}
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}
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return OP_FAILURE;
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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 HopByHopHeader::protocol_id() const {
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return HEADER_TYPE_IPv6_HOPOPT;
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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 HopByHopHeader::validate(){
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nping_ipv6_ext_hopbyhop_opt_t *curr_opt=NULL;
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u8 *curr_pnt=(u8 *)this->h.options;
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int bytes_left=this->length-2;
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/* Check the object's length makes sense*/
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if(this->length%8!=0 || this->length < HOPBYHOP_MIN_HEADER_LEN || this->length > HOPBYHOP_MAX_HEADER_LEN){
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return OP_FAILURE;
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}
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/* Check the header's length field. It should match the object's length */
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if( (this->h.len+1)*8 != this->length){
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return OP_FAILURE;
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}
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/* Now validate the TLV-encoded options. */
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while(bytes_left>0){
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/* Use the opts structure as a template to access current option */
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curr_opt=(nping_ipv6_ext_hopbyhop_opt_t *)curr_pnt;
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/* Let's see what we have. */
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switch(curr_opt->type){
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/* Pad1
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+-+-+-+-+-+-+-+-+
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| 0 |
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+-+-+-+-+-+-+-+-+ */
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case EXTOPT_PAD1:
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curr_pnt++; /* Skip one octet */
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bytes_left++;
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break;
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/* PadN
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- - - - - - - - -
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| 1 | Padding Len | Padding
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- - - - - - - - - */
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case EXTOPT_PADN:
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/* Check we have as many octets as the option advertises */
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if(bytes_left<2+curr_opt->len)
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return OP_FAILURE;
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curr_pnt+=2+curr_opt->len;
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bytes_left-=2+curr_opt->len;
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break;
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/* Jumbo Payload Option (RFC 2675).
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Option Type | Opt Data Len |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Jumbo Payload Length |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */
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case EXTOPT_JUMBO:
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/* Jumbo has a fixed length of 4 octets (plus 2). */
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if(curr_opt->len!=4)
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return OP_FAILURE;
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/* Check if we actually have all the octets */
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if(bytes_left<2+4)
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return OP_FAILURE;
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curr_pnt+=6;
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bytes_left-=6;
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break;
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/* Tunnel Encapsulation limit (RFC 2473).
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Option Type | 1 | Tun Encap Lim |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */
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case EXTOPT_TUNENCAPLIM:
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/* This one also has a fixed length. */
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if(curr_opt->len!=1)
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return OP_FAILURE;
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/* Check if we actually have all the octets */
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if(bytes_left<2+1)
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return OP_FAILURE;
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curr_pnt+=3;
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bytes_left-=3;
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break;
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/* Router Alert (RFC 2711).
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Option Type | 2 | Value (2 octets) |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */
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case EXTOPT_ROUTERALERT:
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/* Fixed length (two octets)*/
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if(curr_opt->len!=2)
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return OP_FAILURE;
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/* Check that we actually have all the octets */
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if(bytes_left<2+2)
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return OP_FAILURE;
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curr_pnt+=4;
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bytes_left-=4;
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break;
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/* Quick-Start (RFC 4782).
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Option | Length=6 | Func. | Rate | Not Used |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| QS Nonce | R |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */
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case EXTOPT_QUICKSTART:
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/* Fixed length (two octets)*/
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if(curr_opt->len!=6)
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return OP_FAILURE;
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/* Check that we actually have all the octets */
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if(bytes_left<2+6)
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return OP_FAILURE;
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curr_pnt+=8;
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bytes_left-=8;
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break;
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/* CALIPSO (RFC 5570).
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+----------------------------+
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| Option Type | Option Length|
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+-------------+---------------+-------------+--------------+
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| CALIPSO Domain of Interpretation |
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+-------------+---------------+-------------+--------------+
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| Cmpt Length | Sens Level | Checksum (CRC-16) |
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+-------------+---------------+-------------+--------------+
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| Compartment Bitmap (Optional; variable length) |
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+-------------+---------------+-------------+--------------+ */
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case EXTOPT_CALIPSO:
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/* The length of the CALIPSO option is variable because the
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* Compartment Bitmap is not mandatory. However, the length
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* must be at least 8. */
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if(curr_opt->len<8)
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return OP_FAILURE;
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/* Check that we actually have all the octets */
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if(bytes_left<2+curr_opt->len)
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return OP_FAILURE;
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curr_pnt+=2+curr_opt->len;
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bytes_left-=2+curr_opt->len;
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break;
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/* Home Address (RFC 6275).
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Option Type | Option Length |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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+ +
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+ Home Address +
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+ +
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+*/
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case EXTOPT_HOMEADDR:
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/* Fixed length of 16 */
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if(curr_opt->len!=16)
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return OP_FAILURE;
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/* Check if we actually have all the octets */
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if(bytes_left<2+16)
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return OP_FAILURE;
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curr_pnt+=18;
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bytes_left-=18;
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break;
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/* Option Type Unknown */
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default:
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/* If we don't know the option, we can still try to validate it,
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* checking if the OptionLength contains something reasonable. */
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/* Fixed length of 16 */
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if(bytes_left<2+curr_opt->len)
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return OP_FAILURE;
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curr_pnt+=2+curr_opt->len;
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bytes_left-=2+curr_opt->len;
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break;
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}
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}
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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 HopByHopHeader::print(FILE *output, int detail) const {
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fprintf(output, "HopByHop[%d,%d]", this->h.nh, this->h.len);
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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 HopByHopHeader::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 HopByHopHeader::getNextHeader(){
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return this->h.nh;
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} /* End of getNextHeader() */
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/* Add TLV encoded option */
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int HopByHopHeader::addOption(u8 type, u8 len, const u8 *data){
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/* Make sure we don't screw up due to buffer length issues */
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if(data==NULL)
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return OP_FAILURE;
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if ( (this->length+len+2) > HOPBYHOP_MAX_HEADER_LEN ) /* No space for more */
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return OP_FAILURE;
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/* Store the option */
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curr_option[0]=type;
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curr_option[1]=len;
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memcpy(curr_option+2, data, len);
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/* Update internal option offset and object's length */
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curr_option+=(len+2);
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this->length+=(len+2);
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this->addPadding();
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return OP_SUCCESS;
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} /* End of addOption() */
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/* If the current length of the extension header is not a multiple of 8 octets,
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* this method adds the necessary padding (either PadN or Pad1 options)*/
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int HopByHopHeader::addPadding(){
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u8 zeroes[8]={0,0,0,0,0,0,0,0};
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int required_octets=8-(this->length%8);
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/* Make sure we have enough space for the padding. */
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if ( (this->length+required_octets) > HOPBYHOP_MAX_HEADER_LEN )
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return OP_FAILURE;
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/* Insert Pad1 or PadN to fill the necessary octets */
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if(required_octets>0 && required_octets<8){
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if(required_octets==1){
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curr_option[0]=EXTOPT_PAD1;
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curr_option++;
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this->length++;
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}else{
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this->addOption(EXTOPT_PADN, required_octets-2, zeroes );
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}
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}
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assert(this->length%8==0);
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this->h.len=(this->length/8)-1;
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return OP_SUCCESS;
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} /* End of addPadding() */
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