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315 lines
12 KiB
C++
315 lines
12 KiB
C++
/***************************************************************************
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* RoutingHeader.cc -- The RoutingHeader Class represents an IPv6 Routing *
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* extension header. *
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***********************IMPORTANT NMAP LICENSE TERMS************************
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*
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* The Nmap Security Scanner is (C) 1996-2025 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
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* add new features. You are highly encouraged to submit your changes as a
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* Github PR or by email to the dev@nmap.org mailing list for possible
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* incorporation into the main distribution. Unless you specify otherwise, it
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* is understood that you are offering us very broad rights to use your
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* submissions as described in the Nmap Public Source License Contributor
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* Agreement. This is important because we fund the project by selling licenses
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* with various terms, and also because the inability to relicense code has
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* caused devastating problems for other Free Software projects (such as KDE
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* 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 "RoutingHeader.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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RoutingHeader::RoutingHeader() {
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this->reset();
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} /* End of RoutingHeader constructor */
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RoutingHeader::~RoutingHeader() {
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} /* End of RoutingHeader destructor */
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/** Sets every attribute to its default value */
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void RoutingHeader::reset(){
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memset(&this->h, 0, sizeof(nping_ipv6_ext_routing_hdr_t));
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this->length=ROUTING_HEADER_MIN_LEN;
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this->curr_addr=(u8 *)this->h.data;
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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 *RoutingHeader::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 RoutingHeader 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 RoutingHeader::storeRecvData(const u8 *buf, size_t len){
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if(buf==NULL || len<ROUTING_HEADER_MIN_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 length and routing type */
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memcpy(&(this->h), buf, 4);
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/* Our behaviour is different depending on the routing type. */
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switch(this->h.type){
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// No checks against ROUTING_HEADER_MAX_LEN because h.len cannot get that large:
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// h.len is u8, max value 0xff, so (0xff+1)*8 = 0x800
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// but ROUTING_HEADER_MAX_LEN is 8+256*8 = 0x808
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/* Routing Type 0 (deprecated by RFC 5095)*/
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case 0:
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/* Type 0 has a variable length, but the value of its HdrExtLen
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* field must be even (because it must be a multiple of the
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* IPv6 address size). We also make sure that the received buffer
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* has as many bytes as the HdrExtLen field says it has, and
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* that it doesn't exceed the maximum number of octets we
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* can store in this object. */
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if(this->h.len%2==1 || ((unsigned int)(this->h.len+1))*8 > 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 pkt_len=(this->h.len+1)*8;
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this->reset();
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this->length=pkt_len;
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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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break;
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/* Routing Type 2 (For IPv6 Mobility. See RFC 6275) */
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case 2:
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/* Type 2 has a fixed length. If we have that many octets, store
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* them. We'll perform validation later in validate(). */
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if(len<ROUTING_TYPE_2_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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this->reset();
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memcpy(&(this->h), buf, ROUTING_TYPE_2_HEADER_LEN);
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this->length=ROUTING_TYPE_2_HEADER_LEN;
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return OP_SUCCESS;
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}
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break;
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/* Unknown routing type */
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default:
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/* If this is some routing type that we don't know about, we'll have
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* to store as much data as the header says it has. Obvioulsy, we
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* check that we received as much data as the HdrExtLen advertises,
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* and that we don't exceed our own internal limit. */
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if( ((unsigned int)(this->h.len+1))*8 > len){
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this->length=0;
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return OP_FAILURE;
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}else{
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this->reset();
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this->length=(this->h.len+1)*8;
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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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break;
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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 RoutingHeader::protocol_id() const {
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return HEADER_TYPE_IPv6_ROUTE;
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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 RoutingHeader::validate(){
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/* Check the object's length makes sense*/
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if(this->length < ROUTING_HEADER_MIN_LEN || this->length%8!=0) {
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return OP_FAILURE;
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}
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switch(this->h.type){
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/* Routing Type 0 (deprecated by RFC 5095)*/
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case 0:
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/* Here we check that:
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* 1) The length in HdrExtLen is even.
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* 2) The length in HdrExtLen matches the octects stored in this object.
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* 3) The length in HdrExtLen does not exceed our internal limit. */
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if(this->h.len%2==1 || (this->h.len+1)*8 != this->length){
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return OP_FAILURE;
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}
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/* Also, for Type 0, the value in the SegmentsLeft field should be less
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* than or equal to the number of addresses in the packet. We verify
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* that using the value of the HDrExtLen field which, divided by two,
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* yields the number of addresses in the packet. It certainly doesn't
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* make sense for the packet to say there are 5 hops left when we
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* have less than 5 IPv6 addresses. We allow it to be less than
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* the number of addresses present in the packet because the RFC 2460
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* only talkes about segleft being greater than HDrExtLen/2, not less. */
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if(this->h.segleft > this->h.len/2){
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return OP_FAILURE;
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}
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break;
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/* Routing Type 2 (For IPv6 Mobility. See RFC 6275) */
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case 2:
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/* Check that we have the exact number of octets we expect. */
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if(this->length!= ROUTING_TYPE_2_HEADER_LEN){
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return OP_FAILURE;
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}
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/* Also check that the HdrExtLen and SegmentsLeft fields have the
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* value that RFC 6275 dictates. */
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if(this->h.segleft!=1 || this->h.len!=2){
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return OP_FAILURE;
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}
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break;
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/* Unknown routing type */
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default:
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/* If this is some routing type that we don't know about, we just
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* check that the length makes sense because we cannot make assumptions
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* about the semantics of other fields. */
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if( this->length!=(this->h.len+1)*8){
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return OP_FAILURE;
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}
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break;
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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 RoutingHeader::print(FILE *output, int detail) const {
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fprintf(output, "Routing[nh=%d len=%d type=%d segleft=%d]", this->h.nh, this->h.len, this->h.type, this->h.segleft);
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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 RoutingHeader::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 RoutingHeader::getNextHeader(){
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return this->h.nh;
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} /* End of getNextHeader() */
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/** Set routing type */
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int RoutingHeader::setRoutingType(u8 val){
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this->h.type = val;
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return OP_SUCCESS;
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} /* End of setRoutingType() */
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/** Returns the routing type */
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u8 RoutingHeader::getRoutingType(){
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return this->h.type;
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} /* End of getRoutingType() */
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/** Set number of segments left */
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int RoutingHeader::setSegmentsLeft(u8 val){
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this->h.segleft = val;
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return OP_SUCCESS;
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} /* End of setSegmentsLeft() */
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/** Returns the number of segments left */
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u8 RoutingHeader::getSegmentsLeft(){
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return this->h.segleft;
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} /* End of getSegmentsLeft() */
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/** Set number of segments left */
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int RoutingHeader::addAddress(struct in6_addr val){
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/* Check we don't exceed max length */
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if((this->length + 16)>ROUTING_HEADER_MAX_LEN)
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return OP_FAILURE;
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memcpy(this->curr_addr, val.s6_addr, 16);
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this->curr_addr+=16;
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this->h.len+=2;
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this->length+=16;
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return OP_SUCCESS;
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} /* End of setSegmentsLeft() */
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